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Sample records for elevating intracranial pressure

  1. Wavelet entropy characterization of elevated intracranial pressure.

    Science.gov (United States)

    Xu, Peng; Scalzo, Fabien; Bergsneider, Marvin; Vespa, Paul; Chad, Miller; Hu, Xiao

    2008-01-01

    Intracranial Hypertension (ICH) often occurs for those patients with traumatic brain injury (TBI), stroke, tumor, etc. Pathology of ICH is still controversial. In this work, we used wavelet entropy and relative wavelet entropy to study the difference existed between normal and hypertension states of ICP for the first time. The wavelet entropy revealed the similar findings as the approximation entropy that entropy during ICH state is smaller than that in normal state. Moreover, with wavelet entropy, we can see that ICH state has the more focused energy in the low wavelet frequency band (0-3.1 Hz) than the normal state. The relative wavelet entropy shows that the energy distribution in the wavelet bands between these two states is actually different. Based on these results, we suggest that ICH may be formed by the re-allocation of oscillation energy within brain.

  2. Biomarkers Prognostic for Elevated Intracranial Pressure

    Science.gov (United States)

    2016-03-01

    Orthopedic injury (n=20) iii) Exclusion of patients with polytrauma . It has been reported that serum ceruloplasmin (as well as copper) levels...inclusion of polytrauma patients in our results. We therefore identified the TBI patients with isolated head trauma, and compared the recorded...ceruloplasmin values between those with elevated ICP and those without. Figure 13 shows that when the patients with polytrauma were excluded from the

  3. Intracranial Pressure

    DEFF Research Database (Denmark)

    Hvedstrup, Jeppe; Radojicic, Aleksandra; Moudrous, Walid

    2018-01-01

    OBJECTIVE: To compare a new method of noninvasive intracranial pressure (nICP) measurement with conventional lumbar puncture (LP) opening pressure. METHODS: In a prospective multicenter study, patients undergoing LP for diagnostic purposes underwent intracranial pressure measurements with HeadSen...

  4. Intracranial hemorrhage in normotensive and hypertensive patients receiving streptokinase after decreasing elevated blood pressure

    Directory of Open Access Journals (Sweden)

    H Shemirani

    2005-09-01

    Full Text Available Background: Many patients with suspected acute myocardial infarction (AMI and eligible for thrombolytic therapy may not be treated because of association between hemorrhagic complications especially intracranial hemorrhage (ICH, and severe hypertension (HTN at presentation. Unfortunately, this leads to under use or delay in thrombolytic therapy. We assessed effect of decreasing elevated blood pressure before thrombolytic therapy in order to reduce the incidence of ICH without increasing mortality rate. Methods: This observational and analytical cohort study enrolled 293 patients (215males and 78 female with STsegment elevation (AMI that were hospitalized in emergency department of Noor hospital, Isfahan, Iran. Severe hypertension (blood pressure ≥180/110mmHg was diagnosed in 132 patients. All of them received 1.5 million units streptokinase within one hour intravenously. In the hypertensive group, elevated blood pressure was lowered to less than180/110mmhg before thrombolysis and they were observed to detect development of symptomatic ICH and they underwent Brain CT scan, if required. Results: The incidence of total stroke, ICH and death were 1.4%, 0.7% and 4.8%, respectively. The incidence of death and ICH in patients with severe hypertension was less than control group (P value=0.13 and 0.59, respectively Conclusion: Although we did not find any increase in ICH incidence in severe hypertensive patients treated be streptokinase due to AMI, but we recommend a multi-centric study with more cases and varied thrombolytic protocols. Key words: Acute myocardial infarction, Intracranial hemorrhage, Thrombolytic therapy

  5. Serum IL-6: a candidate biomarker for intracranial pressure elevation following isolated traumatic brain injury

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    Ward Norman H

    2010-03-01

    Full Text Available Abstract Background Increased intracranial pressure (ICP is a serious, life-threatening, secondary event following traumatic brain injury (TBI. In many cases, ICP rises in a delayed fashion, reaching a maximal level 48-96 hours after the initial insult. While pressure catheters can be implanted to monitor ICP, there is no clinically proven method for determining a patient's risk for developing this pathology. Methods In the present study, we employed antibody array and Luminex-based screening methods to interrogate the levels of inflammatory cytokines in the serum of healthy volunteers and in severe TBI patients (GCS≤8 with or without incidence of elevated intracranial pressure (ICP. De-identified samples and ELISAs were used to confirm the sensitivity and specificity of IL-6 as a prognostic marker of elevated ICP in both isolated TBI patients, and polytrauma patients with TBI. Results Consistent with previous reports, we observed sustained increases in IL-6 levels in TBI patients irrespective of their ICP status. However, the group of patients who subsequently experienced ICP ≥ 25 mm Hg had significantly higher IL-6 levels within the first 17 hours of injury as compared to the patients whose ICP remained ≤20 mm Hg. When blinded samples (n = 22 were assessed, a serum IL-6 cut-off of 128 pg/ml correctly identified 85% of isolated TBI patients who subsequently developed elevated ICP, and values between these cut-off values correctly identified 75% of all patients whose ICP remained ≤20 mm Hg throughout the study period. In contrast, the marker had no prognostic value in predicting elevated ICP in polytrauma patients with TBI. When the levels of serum IL-6 were assessed in patients with orthopedic injury (n = 7 in the absence of TBI, a significant increase was found in these patients compared to healthy volunteers, albeit lower than that observed in TBI patients. Conclusions Our results suggest that serum IL-6 can be used for the

  6. Elevated intracranial pressure and reversible eye-tracking changes detected while viewing a film clip.

    Science.gov (United States)

    Kolecki, Radek; Dammavalam, Vikalpa; Bin Zahid, Abdullah; Hubbard, Molly; Choudhry, Osamah; Reyes, Marleen; Han, ByoungJun; Wang, Tom; Papas, Paraskevi Vivian; Adem, Aylin; North, Emily; Gilbertson, David T; Kondziolka, Douglas; Huang, Jason H; Huang, Paul P; Samadani, Uzma

    2018-03-01

    OBJECTIVE The precise threshold differentiating normal and elevated intracranial pressure (ICP) is variable among individuals. In the context of several pathophysiological conditions, elevated ICP leads to abnormalities in global cerebral functioning and impacts the function of cranial nerves (CNs), either or both of which may contribute to ocular dysmotility. The purpose of this study was to assess the impact of elevated ICP on eye-tracking performed while patients were watching a short film clip. METHODS Awake patients requiring placement of an ICP monitor for clinical purposes underwent eye tracking while watching a 220-second continuously playing video moving around the perimeter of a viewing monitor. Pupil position was recorded at 500 Hz and metrics associated with each eye individually and both eyes together were calculated. Linear regression with generalized estimating equations was performed to test the association of eye-tracking metrics with changes in ICP. RESULTS Eye tracking was performed at ICP levels ranging from -3 to 30 mm Hg in 23 patients (12 women, 11 men, mean age 46.8 years) on 55 separate occasions. Eye-tracking measures correlating with CN function linearly decreased with increasing ICP (p short film clip. These results suggest that eye tracking may be used as a noninvasive, automatable means to quantitate the physiological impact of elevated ICP, which has clinical application for assessment of shunt malfunction, pseudotumor cerebri, concussion, and prevention of second-impact syndrome.

  7. Risk of Microgravity-Induced Visual Impairment and Elevated Intracranial Pressure (VIIP)

    Science.gov (United States)

    Otto, Christian

    2011-01-01

    Eight cases identified, represent 23.5% of the 34 crewmembers flown on the ISS, with inflight visual changes and pre-to-postflight refractive changes. In some cases, the changes were transient while in others they are persistent with varying degrees of visual impairment. (1) Decreased intraocular pressure (IOP) postflight was observed in 3 cases. (2) Fundoscopic exams revealed postflight findings of choroidal folds in 4 cases, optic disc edema in 5 cases and presence of cotton wool spots in 3 cases. (3) Optical coherence tomography (OCT) confirmed findings of choroidal folds and disc edema and documented retinal nerve fiber layer thickening (4 cases). (4) Findings from MRI examinations showed posterior globe flattening (5 cases) and optic nerve sheath distension (6 cases). (5) Opening cerebrospinal fluid (CSF) pressure was elevated in 4 cases postflight reflecting raised intracranial pressure. While the etiology remains unknown, hypotheses speculate that venous insufficiency or hypertension in the brain caused by cephalad fluid shifts during spaceflight are possible mechanisms for ocular changes in astronauts.

  8. Increased intracranial pressure

    Science.gov (United States)

    ... the membranes covering the brain and spinal cord) Subdural hematoma (bleeding between the covering of the brain and ... intracranial pressure Patient Instructions Ventriculoperitoneal shunt - discharge Images Subdural hematoma Central nervous system and peripheral nervous system References ...

  9. Raised intracranial pressure

    African Journals Online (AJOL)

    is article presents an approach to raised intracranial pressure (ICP) constructed in a question-answer fashion. ..... Given that raised ICP is a serious and potentially life-threatening emergency, fast and reliable referral and transfer mechanisms should be established to ensure patients with this condition are effectively treated.

  10. Intracranial Pressure Monitoring

    DEFF Research Database (Denmark)

    Raboel, P H; Bartek, J; Andresen, M

    2012-01-01

    Monitoring of intracranial pressure (ICP) has been used for decades in the fields of neurosurgery and neurology. There are multiple techniques: invasive as well as noninvasive. This paper aims to provide an overview of the advantages and disadvantages of the most common and well-known methods...

  11. Monitoring of Intracranial Pressure During Intracranial Endoscopy

    Directory of Open Access Journals (Sweden)

    Rajeev Kumar

    2013-08-01

    Full Text Available Background: Intracranial endoscopy is a minimum invasive procedure, which reduces trauma to the brain, is cost-effective, and carries a shortened hospital stay with an improved postoperative outcome. Objective: To monitor intracranial pressure changes during intracranial endoscopy among children and adults under general anesthesia/sedation, and to compare the intracranial pressure changes between children and adults receiving general anesthesia and among adults receiving general anesthesia and sedation. Methods: The present cross-sectional study was conducted in one of the tertiary care hospitals of Lucknow. This was carried out in the department of neurosurgery from January 2008 to December 2008. Patients who were not fit for general anesthesia received local anesthesia under sedation. Patients participating in the study were divided into three groups. Intracranial pressure was recorded at specific intervals. Parametric data were subjected to statistical analysis using a student\\s t test. Result: A total of 70 patients were undergoing intracranial endoscopy under general anesthesia during the study period. In both groups A and B, intracranial pressure increases the maximum during inflation of the balloon. In group C, all the variations in ICP were found to be statistically significant. In the comparison of intracranial pressure changes between groups A and B, no significant difference was found. All correlations in the comparison of groups B and C were found to be statistically significant (p< 0.001. Conclusion: There is a need for continuous intraoperative monitoring of ICP intracranial endoscopy, because ICP increases in various stages of the procedure, which can be detrimental to the perfusion of the brain. [Arch Clin Exp Surg 2013; 2(4.000: 240-245

  12. The Cushing Reflex: Oliguria as a Reflection of an Elevated Intracranial Pressure

    Directory of Open Access Journals (Sweden)

    K. Leyssens

    2017-01-01

    Full Text Available Oliguria is one of the clinical hallmarks of renal failure. The broad differential diagnosis is well known, but a rare cause of oliguria is intracranial hypertension (ICH. The actual knowledge to explain this relationship is scarce. Almost all literature is about animals where authors describe the Cushing reflex in response to ICH. We hypothesize that the Cushing reflex is translated towards the sympathetic nervous system and renin-angiotensin-aldosterone system with a subsequent reduction in medullary blood flow and oliguria. Recently, we were confronted with a patient who had complicated pituitary surgery and displayed multiple times an oliguria while he developed ICH.

  13. Cerebral blood flow changes in response to elevated intracranial pressure in rabbits and bluefish: a comparative study.

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    Beiner, J M; Olgivy, C S; DuBois, A B

    1997-03-01

    In mammals, the cerebrovascular response to increases in intracranial pressure may take the form of the Cushing response, which includes increased mean systemic arterial pressure, bradycardia and diminished respirations. The mechanism, effect and value of these responses are debated. Using laser-Doppler flowmetry to measure cerebral blood flow, we analyzed the cardiovascular responses to intracranial pressure raised by epidural infusion of mock cerebrospinal fluid in the bluefish and in the rabbit, and compare the results. A decline in cerebral blood flow preceding a rise in mean systemic arterial pressure was observed in both species. Unlike bluefish, rabbits exhibit a threshold of intracranial pressure below which cerebral blood flow was maintained and no cardiovascular changes were observed. The difference in response between the two species was due to the presence of an active autoregulatory system in the cerebral tissue of rabbits and its absence in bluefish. For both species studied, the stimulus for the Cushing response seems to be a decrement in cerebral blood flow. The resulting increase in the mean systemic arterial pressure restores cerebral blood flow to levels approaching controls.

  14. Intracranial Pressure Elevation 24 Hours after Ischemic Stroke in Aged Rats is Prevented by Early, Short Hypothermia Treatment

    Directory of Open Access Journals (Sweden)

    Lucy Anne Murtha

    2016-05-01

    Full Text Available Stroke is predominantly a senescent disease, yet most preclinical studies investigate treatment in young animals. We recently demonstrated that short-duration hypothermia-treatment completely prevented the dramatic intracranial pressure (ICP rise seen post-stroke in young rats. Here, our aim was to investigate whether a similar ICP rise occurs in aged rats and to determine whether short-duration hypothermia is an effective treatment in aged animals. Experimental Middle Cerebral Artery occlusion (MCAo - 3 hour occlusion was performed on male Wistar rats aged 19-20 months. At one hour after stroke-onset, rats were randomized to 2.5 hours hypothermia-treatment (32.5 °C or normothermia (37 °C. ICP was monitored at baseline, for 3.5 hours post-occlusion, and at 24 hours post-stroke. Infarct and edema volumes were calculated from histology. Baseline pre-stroke ICP was 11.2 ± 3.3 mmHg across all animals. Twenty-four hours post-stroke, ICP was significantly higher in normothermic animals compared to hypothermia-treated animals (27.4 ± 18.2 mmHg vs. 8.0 ± 5.0 mmHg, p = 0.03. Infarct and edema volumes were not significantly different between groups. These data demonstrate ICP may also increase 24 hours post-stroke in aged rats, and that short-duration hypothermia treatment has a profound and sustained preventative effect. These findings may have important implications for the use of hypothermia in clinical trials of aged stroke patients.

  15. Effect of Elevated Intracranial Pressure on Amplitudes and Frequency Tuning of Ocular Vestibular Evoked Myogenic Potentials Elicited by Bone-Conducted Vibration.

    Science.gov (United States)

    Gürkov, Robert; Speierer, Guillaume; Wittwer, Luis; Kalla, Roger

    Recently, it could be demonstrated that an increased intracranial pressure causes a modulation of the air conducted sound evoked ocular vestibular evoked myogenic potential (oVEMP). The mechanism for this modulation is not resolved and may depend on a change of either receptor excitability or sound energy transmission. oVEMPs were elicited in 18 healthy subjects with a minishaker delivering 500 and 1000 Hz tone bursts, in supine and tilted positions. The study could confirm the frequency tuning of oVEMP. However, at neither stimulus frequency could a modulating effect of increased intracranial pressure be observed. These data suggest that the observed modulation of the oVEMP response by an increased intracranial pressure is primarily due to the effect of an increased intralabyrinthine pressure onto the stiffness of the inner ear contents and the middle ear-inner ear junction. Future studies on the effect of intracranial pressure on oVEMP should use air-conducted sound and not bone-conducted vibration.

  16. Microoptomechanical sensor for intracranial pressure monitoring

    International Nuclear Information System (INIS)

    Andreeva, A V; Luchinin, V V; Lutetskiy, N A; Sergushichev, A N

    2014-01-01

    The main idea of this research is the development of microoptomechanical sensor for intracranial pressure monitoring. Currently, the authors studied the scientific and technical knowledge in this field, as well as develop and test a prototype of microoptomechanical sensor for intracranial pressure (ICP) monitoring

  17. Increased Intracranial Pressure in the Setting of Enterovirus and Other Viral Meningitides

    Directory of Open Access Journals (Sweden)

    Jules C. Beal

    2017-01-01

    Full Text Available Increased intracranial pressure due to viral meningitis has not been widely discussed in the literature, although associations with Varicella and rarely Enterovirus have been described. Patients with increased intracranial pressure and cerebrospinal fluid analysis suggestive of a viral process are sometimes classified as having atypical idiopathic intracranial hypertension (IIH. However, a diagnosis of IIH requires normal cerebrospinal fluid, and therefore in these cases an infection with secondary intracranial hypertension may be a more likely diagnosis. Here seven patients are presented with elevated intracranial pressure and cerebrospinal fluid suggestive of viral or aseptic meningitis. Of these, 1 had Enterovirus and the remainder were diagnosed with nonspecific viral meningitis. These data suggest that viral meningitis may be associated with elevated intracranial pressure more often than is commonly recognized. Enterovirus has previously been associated with increased intracranial pressure only in rare case reports.

  18. Increased intracranial pressure: evaluation by computerized tomography

    International Nuclear Information System (INIS)

    Lightfoote, W.E.; Pressman, B.D.

    1975-01-01

    Computerized tomography is clearly very useful in the evaluation of patients with increased intracranial pressure and suspected pseudotumor cerebri. It provides an index of ventricular size and configuration and has the capability of demonstrating intracranial lesions. Moreover, this new technique is rapid and non-invasive, and is without attendant risks. Examinations may be performed serially as the clinical process evolves, thereby giving roentgenographic correlation to the clinical features. (U.S.)

  19. Use of intracranial pressure monitoring in bacterial meningitis

    DEFF Research Database (Denmark)

    Larsen, Lykke; Rom Poulsen, Frantz; Nielsen, Troels H

    2017-01-01

    BACKGROUND: The aim of this study was to evaluate the clinical outcome of patients with severe bacterial meningitis where intracranial pressure (ICP) monitoring has been performed. METHODS: A retrospective observational study including patients admitted 1st(.) January 2005 to 31st(.) December 2014...... CT scans with signs of elevated ICP. CONCLUSIONS: Patients with severe meningitis should be admitted to intensive care units and evaluated for ICP monitoring regardless of head CT findings....

  20. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    International Nuclear Information System (INIS)

    Liu Xiong; Yao Yan; Ma Jiahao; Zhang Zhaohua; Zhang Yanhang; Wang Qian; Ren Tianling

    2015-01-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm 2 . It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm 2 . In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm 2 . Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10 −2 mV/kPa. (paper)

  1. Cerebrospinal Fluid Corticosteroid Levels and Cortisol Metabolism in Patients with Idiopathic Intracranial Hypertension : A Link between 11 beta-HSD1 and Intracranial Pressure Regulation?

    NARCIS (Netherlands)

    Sinclair, Alexandra J.; Walker, Elizabeth A.; Burdon, Michael A.; van Beek, Andre P.; Kema, Ido P.; Hughes, Beverly A.; Murray, Philip I.; Nightingale, Peter G.; Stewart, Paul M.; Rauz, Saaeha; Tomlinson, Jeremy W.

    2010-01-01

    Context: The etiology of idiopathic intracranial hypertension (IIH) is unknown. We hypothesized that obesity and elevated intracranial pressure may be linked through increased 11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) activity. Objective: The aim was to characterize 11 beta-HSD1 in

  2. PATHOGENESIS OF OPTIC DISC EDEMA IN RAISED INTRACRANIAL PRESSURE

    Science.gov (United States)

    Hayreh, Sohan Singh

    2015-01-01

    Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with

  3. Intracranial Pressure Monitoring—Review and Avenues for Development

    Directory of Open Access Journals (Sweden)

    Maya Harary

    2018-02-01

    Full Text Available Intracranial pressure (ICP monitoring is a staple of neurocritical care. The most commonly used current methods of monitoring in the acute setting include fluid-based systems, implantable transducers and Doppler ultrasonography. It is well established that management of elevated ICP is critical for clinical outcomes. However, numerous studies show that current methods of ICP monitoring cannot reliably define the limit of the brain’s intrinsic compensatory capacity to manage increases in pressure, which would allow for proactive ICP management. Current work in the field hopes to address this gap by harnessing live-streaming ICP pressure-wave data and a multimodal integration with other physiologic measures. Additionally, there is continued development of non-invasive ICP monitoring methods for use in specific clinical scenarios.

  4. Robust Peak Recognition in Intracranial Pressure Signals

    Directory of Open Access Journals (Sweden)

    Bergsneider Marvin

    2010-10-01

    Full Text Available Abstract Background The waveform morphology of intracranial pressure pulses (ICP is an essential indicator for monitoring, and forecasting critical intracranial and cerebrovascular pathophysiological variations. While current ICP pulse analysis frameworks offer satisfying results on most of the pulses, we observed that the performance of several of them deteriorates significantly on abnormal, or simply more challenging pulses. Methods This paper provides two contributions to this problem. First, it introduces MOCAIP++, a generic ICP pulse processing framework that generalizes MOCAIP (Morphological Clustering and Analysis of ICP Pulse. Its strength is to integrate several peak recognition methods to describe ICP morphology, and to exploit different ICP features to improve peak recognition. Second, it investigates the effect of incorporating, automatically identified, challenging pulses into the training set of peak recognition models. Results Experiments on a large dataset of ICP signals, as well as on a representative collection of sampled challenging ICP pulses, demonstrate that both contributions are complementary and significantly improve peak recognition performance in clinical conditions. Conclusion The proposed framework allows to extract more reliable statistics about the ICP waveform morphology on challenging pulses to investigate the predictive power of these pulses on the condition of the patient.

  5. Blood Pressure Is the Determinant for the Increased Risk for Intracranial Arterial Stenosis in Subjects with Elevated Glycated Hemoglobin Levels: The Kangbuk Samsung Health Study.

    Science.gov (United States)

    Oh, Hyung-Geun; Rhee, Eun-Jung

    2016-11-01

    Ischemic stroke is known to be an important vascular complication of diabetes. Intracranial arterial stenosis (ICAS) is considered as an important cause of stroke in Asians. We aimed to analyze the risk for ICAS assessed by transcranial Doppler (TCD) ultrasonography in different groups of young Korean subjects divided by glycated hemoglobin (HbA1c) levels. This study included 10,437 participants without history of cardiovascular diseases (81.3% men, mean age 43 years) from a health screening program, in whom TCD ultrasonography was used to detect greater than 50% ICAS based on criteria modified from the SONIA (Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis) trial. The subjects were divided into 3 groups according to HbA1c levels: HbA1c < 5.7%, 5.7 ≤ HbA1c < 6.5%, and HbA1c ≥ 6.5% or under medication for diabetes. Among the participants, 3.0% of the subjects had ICAS. The subjects with ICAS tended to have higher mean HbA1c level compared with those without ICAS (5.8 ± .8 versus 5.7 ± .6, P = .063). The proportion of subjects with ICAS significantly increased as the HbA1c increased from the first to the third group (2.8%, 3.0%, 4.6%, P for linear trend = .022). In logistic regression analysis with ICAS as the dependent variable, the group with HbA1c ≥ 6.5% showed significantly increased odds ratio for ICAS with subjects with HbA1c < 5.7% as the reference after adjustment for confounding variables (1.575, 95% confidence interval 1.056-2.347). However, this significance disappeared with inclusion of presence of hypertension in the model. The risk for ICAS assessed by TCD was increased in young Korean subjects with HbA1c ≥ 6.5%. However, this significance was attenuated after adjustment for presence of hypertension, suggesting the importance of hypertension in ICAS. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  6. Organic electronics based pressure sensor towards intracranial pressure monitoring

    Science.gov (United States)

    Rai, Pratyush; Varadan, Vijay K.

    2010-04-01

    The intra-cranial space, which houses the brain, contains cerebrospinal fluid (CSF) that acts as a fluid suspension medium for the brain. The CSF is always in circulation, is secreted in the cranium and is drained out through ducts called epidural veins. The venous drainage system has inherent resistance to the flow. Pressure is developed inside the cranium, which is similar to a rigid compartment. Normally a pressure of 5-15 mm Hg, in excess of atmospheric pressure, is observed at different locations inside the cranium. Increase in Intra-Cranial Pressure (ICP) can be caused by change in CSF volume caused by cerebral tumors, meningitis, by edema of a head injury or diseases related to cerebral atrophy. Hence, efficient ways of monitoring ICP need to be developed. A sensor system and monitoring scheme has been discussed here. The system architecture consists of a membrane less piezoelectric pressure sensitive element, organic thin film transistor (OTFT) based signal transduction, and signal telemetry. The components were fabricated on flexible substrate and have been assembled using flip-chip packaging technology. Material science and fabrication processes, subjective to the device performance, have been discussed. Capability of the device in detecting pressure variation, within the ICP pressure range, is investigated and applicability of measurement scheme to medical conditions has been argued for. Also, applications of such a sensor-OTFT assembly for logic sensor switching and patient specific-secure monitoring system have been discussed.

  7. Visual Impairment/Intracranial Pressure Risk Assessment

    Science.gov (United States)

    Fogarty, Jennifer A.; Durham, T.; Otto, C.; Grounds, D.; Davis, J. R.

    2010-01-01

    Since 2006 there have been 6 reported cases of altered visual acuity and intracranial pressure (ICP) in long duration astronauts. In order to document this risk and develop an integrated approach to its mitigation, the NASA Space Life Sciences Directorate (SLSD) and Human Research Program (HRP) have chosen to use the Human System Risk Board (HSRB) and the risk management analysis tool (RMAT). The HSRB is the venue in which the stakeholders and customers discuss and vet the evidence and the RMAT is the tool that facilitates documentation and comparison of the evidence across mission profiles as well as identification of risk factors, and documentation of mitigation strategies. This process allows for information to be brought forward and dispositioned so that it may be properly incorporated into the RMAT and contribute to the design of the research and mitigation plans. The evidence thus far has resulted in the identification of a visual impairment/intracranial pressure (VIIP) project team, updating of both short and long duration medical requirements designed to assess visual acuity, and a research plan to characterize this issue further. In order to understand this issue more completely, a plan to develop an Accelerated Research Collaboration (ARC) has been approved by the HSRB. The ARC is a novel research model pioneered by the Myelin Repair Foundation. It is a patient centered research model that brings together researchers and clinicians, under the guidance of a scientific advisory panel, to collaborate and produce results much quickly than accomplished through traditional research models. The data and evidence from the updated medical requirements and the VIIP ARC will be reviewed at the HSRB on a regular basis. Each review package presented to the HSRB will include an assessment and recommendation with respect to continuation of research, countermeasure development, occupational surveillance modalities, selection criteria, etc. This process will determine the

  8. Quantifying response to intracranial pressure normalization in idiopathic intracranial hypertension via dynamic neuroimaging.

    Science.gov (United States)

    Lublinsky, Svetlana; Kesler, Anat; Friedman, Alon; Horev, Anat; Shelef, Ilan

    2018-04-01

    Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure without a clear cause. To investigate dynamic imaging findings in IIH and their relation to mechanisms underlying intracranial pressure normalization. Prospective. Eighteen IIH patients and 30 healthy controls. T 1 -weighted, venography, fluid attenuation inversion recovery, and apparent diffusion coefficients were acquired on 1.5T scanner. The dural sinus was measured before and after lumbar puncture (LP). The degree of sinus occlusion was evaluated, based on 95% confidence intervals of controls. We studied a number of neuroimaging biomarkers associated with IIH (sinus occlusion; optic nerve; distribution of cerebrospinal fluid into the subarachnoid space, sulci and lateral ventricles (LVs); Meckel's caves; arachnoid granulation; pituitary and choroid plexus), before and after LP, using a set of specially developed quantification techniques. Relationships among various biomarkers were investigated (Pearson correlation coefficient) and linked to long-term disease outcomes (logistic regression). The t-test and the Wilcoxon rank test were used to compare between controls and before and after LP data. As a result of LP, the following were found to be in good accordance with the opening pressure: relative compression of cerebrospinal fluid (R = -0.857, P < 0.001) and brain volumes (R = -0.576, P = 0.012), LV expansion (R = 0.772, P < 0.001) and venous volume (R = 0.696, P = 0.001), enlargement of the pituitary (R = 0.640, P = 0.023), and shrinkage of subarachnoid space (R = -0.887, P < 0.001). The only parameter that had an impact on long-term prognosis was cross-sectional size of supplemental drainage veins after LP (sensitivity of 92%, specificity of 20%, and area under the curve of 0.845, P < 0.001). We present an approach for quantitative characterization of the intracranial venous system and its implementation as a diagnostic assistance

  9. Diagnostic value of optical coherence tomography for intracranial pressure in idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Skau, M; Yri, H; Sander, B

    2013-01-01

    BACKGROUND: Idiopathic intracranial hypertension (IIH) is a condition of raised intracranial pressure (ICP) in the absence of space-occupying lesions or other known etiology. It primarily affects young obese females, and potentially causes permanent visual loss due to papilledema and secondary...... optic atrophy. The aim of this study was to evaluate the diagnostic value of optical coherence tomography (OCT) as a marker for CSF opening pressure in patients with idiopathic intracranial hypertension (IIH). METHODS: We conducted a case-control study of 20 newly diagnosed, 21 long-term IIH patients...

  10. Probabilistic Modeling of Intracranial Pressure Effects on Optic Nerve Biomechanics

    Science.gov (United States)

    Ethier, C. R.; Feola, Andrew J.; Raykin, Julia; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.

    2016-01-01

    Altered intracranial pressure (ICP) is involved/implicated in several ocular conditions: papilledema, glaucoma and Visual Impairment and Intracranial Pressure (VIIP) syndrome. The biomechanical effects of altered ICP on optic nerve head (ONH) tissues in these conditions are uncertain but likely important. We have quantified ICP-induced deformations of ONH tissues, using finite element (FE) and probabilistic modeling (Latin Hypercube Simulations (LHS)) to consider a range of tissue properties and relevant pressures.

  11. Monitoring of Intracranial Pressure in Meningitis.

    Science.gov (United States)

    Depreitere, Bart; Bruyninckx, Dominike; Güiza, Fabian

    2016-01-01

    The literature on intracranial pressure (ICP) monitoring in meningitis is limited to case reports and a handful of descriptive series. The aim of this study is to investigate relationships among ICP, cerebral perfusion pressure (CPP), and outcome in meningitis and to identify whether ICP affected clinical decisions. Between 1999 and 2011, a total of 17 patients with meningitis underwent ICP monitoring at the University Hospitals Leuven. Charts were reviewed for clinical history, ICP/CPP data, imaging findings, and Glasgow Outcome Scale score. Univariate correlations were computed for outcome and ICP/CPP variables, computed tomography characteristics, and Corticosteroid Randomization After Significant Head Injury outcome model variables. Treatment decisions were assessed regarding whether or not they were based on ICP. At drain placement, Glasgow Coma Scale scores showed a median of 8 (range 3-12). Six of 17 patients had either one or two nonreactive pupils. Significant correlations with outcome were found for the highest documented ICP value (r = -0.70), the number of episodes when CPP meningitis high ICP and low CPP represent secondary insults. The poor condition of the patients illustrates that the level of suspicion for increased ICP in meningitis may not be high enough.

  12. A whole-body mathematical model for intracranial pressure dynamics.

    Science.gov (United States)

    Lakin, William D; Stevens, Scott A; Tranmer, Bruce I; Penar, Paul L

    2003-04-01

    Most attempts to study intracranial pressure using lumped-parameter models have adopted the classical "Kellie-Monro Doctrine," which considers the intracranial space to be a closed system that is confined within the nearly-rigid skull, conserves mass, and has equal inflow and outflow. The present work revokes this Doctrine and develops a mathematical model for the dynamics of intracranial pressures, volumes, and flows that embeds the intracranial system in extensive whole-body physiology. The new model consistently introduces compartments representing the tissues and vasculature of the extradural portions of the body, including both the thoracic region and the lower extremities. In addition to vascular connections, a spinal-subarachnoid cerebrospinal fluid (CSF) compartment bridges intracranial and extracranial physiology allowing explict buffering of intracranial pressure fluctuations by the spinal theca. The model contains cerebrovascular autoregulation, regulation of systemic vascular pressures by the sympathetic nervous system, regulation of CSF production in the choroid plexus, a lymphatic system, colloid osmotic pressure effects, and realistic descriptions of cardiac output. To validate the model in situations involving normal physiology, the model's response to a realistic pulsatile cardiac output is examined. A well-known experimentally-derived intracranial pressure-volume relationship is recovered by using the model to simulate CSF infusion tests, and the effect on cerebral blood flow of a change in body position is also examined. Cardiac arrest and hemorrhagic shock are simulated to demonstrate the predictive capabilities of the model in pathological conditions.

  13. Cerebral Pulsatility Index Is Elevated in Patients with Elevated Right Atrial Pressure.

    Science.gov (United States)

    Lahiri, Shouri; Schlick, Konrad H; Padrick, Matthew M; Rinsky, Brenda; Gonzalez, Nestor; Jones, Heather; Mayer, Stephan A; Lyden, Patrick D

    2018-01-01

    Extracerebral venous congestion can precipitate intracranial hypertension due to obstruction of cerebral blood outflow. Conditions that increase right atrial pressure, such as hypervolemia, are thought to increase resistance to jugular venous outflow and contribute to cerebro-venous congestion. Cerebral pulsatility index (CPI) is considered a surrogate marker of distal cerebrovascular resistance and is elevated with intracranial hypertension. Thus, we sought to test the hypothesis that elevated right atrial pressure is associated with increased CPI compared to normal right atrial pressure. We retrospectively reviewed 61 consecutive patients with subarachnoid hemorrhage. We calculated CPI from transcranial Doppler studies and correlated these with echocardiographic measures of right atrial pressure. CPIs were compared from patients with elevated and normal right atrial pressure. There was a significant difference between CPI obtained from all patients with elevated right atrial pressure compared to those with normal right atrial pressure (P right and left hemispheric CPI from patients with both elevated and normal right atrial pressure. Patients with elevated right atrial pressure had significantly higher CPI compared to patients with normal right atrial pressure. These findings suggest that cerebro-venous congestion due to impaired jugular venous outflow may increase distal cerebrovascular resistance as measured by CPI. Since elevated CPI is associated with poor outcome in numerous neurological conditions, future studies are needed to elucidate the significance of these results in other populations. Copyright © 2017 by the American Society of Neuroimaging.

  14. Intracranial Pressure during HighVolume Hemofiltration in Severe Sepsis

    Directory of Open Access Journals (Sweden)

    A. P. Berdnikov

    2014-01-01

    Full Text Available Objective: to define the prognostic value of intracranial pressure (ICP changes in highvolume hemofiltration (HVHF in patients with severe sepsis and normal preperfusion ICP.Subjects and methods. A retrospective study was conducted in 50 patients (a total of 134 sessions with severe sepsis and normal baseline ICP who received ther apy using HVHF for extrarenal indications. Based on ICP changes before and after HVHF, the investigators identified 2 groups: 1 no ICP changes (n=81; 2 elevated ICP (n=53.Conclusion. HVHF is ineffective when the normal preperfusion ICP is increased in patients with severe sepsis who have a concurrence of an arteriovenous carbon dioxide difference of more than 8 mm Hg and a Glasgow coma score of less than 10.

  15. Routine intracranial pressure monitoring in acute coma.

    Science.gov (United States)

    Forsyth, Rob J; Raper, Joseph; Todhunter, Emma

    2015-11-02

    We know that the brain damage resulting from traumatic and other insults is not due solely to the direct consequences of the primary injury. A significant and potentially preventable contribution to the overall morbidity arises from secondary hypoxic-ischaemic damage. Brain swelling accompanied by raised intracranial pressure (ICP) prevents adequate cerebral perfusion with well-oxygenated blood.Detection of raised ICP could be useful in alerting clinicians to the need to improve cerebral perfusion, with consequent reductions in brain injury. To determine whether routine ICP monitoring in severe coma of any cause reduces the risk of all-cause mortality or severe disability at final follow-up. We searched the Cochrane Injuries Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL Plus, ISI Web of Science (SCI-EXPANDED & CPCI-S), clinical trials registries and reference lists. We ran the most recent search on 22 May 2015. All randomised controlled studies of real-time ICP monitoring by invasive or semi-invasive means in acute coma (traumatic or non-traumatic aetiology) versus clinical care without ICP monitoring (that is, guided only by clinical or radiological inference of the presence of raised ICP). Two authors (ET and RF) worked independently to identify the one study that met inclusion criteria. JR and RF independently extracted data and assessed risk of bias. We contacted study authors for additional information, including details of methods and outcome data. One randomized controlled trial (RCT) meeting the selection criteria has been identified to date.The included study had 324 participants. We judged risk of bias to be low for all categories except blinding of participants and personnel, which is not feasible for this intervention. There were few missing data, and we analysed all on an intention-to-treat basis.Participants could be 13 years of age or older (mean age of sample 29

  16. Non-Invasive Measurement of Pulsatile Intracranial Pressures Using Ultrasound

    Science.gov (United States)

    Ueno, Toshiaki; Ballard, Richard E.; Shuer, Lawrence M.; Cantrell, John H.; Cantrell, John H.; Hargens, Alan R.

    1997-01-01

    Early detection of elevated intracranial pressure (ICP) will aid clinical decision-making for head trauma, brain tumor and other cerebrovascular diseases. Conventional methods, however, require surgical procedures which take time and are accompanied by increased risk of infection. Accordingly we have developed and refined a new ultrasound device to measure skull movements which are known to occur in conjunction with altered ICP. The principle of this device is based upon pulse phase locked loop (PPLL), which enables us to detect changes in distance on the order of microns between an ultrasound transducer on one side of the skull and the opposite inner surface of the cranium. The present study was designed to verify this measurement technique in cadavera. Transcranial distance was increased in steps of 10 mmHg from zero to 50 mmHg by saline infusion into the lateral ventricle of two cadavera. In separate experiments, pulsations of ICP with the amplitudes of zero to 2 mmHg were generated by rhythmic injections of saline using a syringe. When the ICP was stepwise increased from zero to 50 mmHg, transcranial distance increased in proportion with the ICP increase (y=12 x - 76, r=0.938), where y is changes in transcranial distance in microns and x is ICP in mmHg. In the data recorded while ICP pulsations were generated, fast Fourier transform analysis demonstrated that cranial pulsations were clearly associated with ICP pulsations. The results indicate that changes in transcranial distance is linearly correlated with those in ICP, and also that the PPLL device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. By analyzing the magnitude of cranial pulsations, we may be able to estimate the pressure-volume index in the cranium. As a result, estimates of intracranial compliance may be possible by using the PPLL device. Further studies are necessary in normal subjects and patients.

  17. Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

    Science.gov (United States)

    Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

    1997-01-01

    Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

  18. Negative-Pressure Hydrocephalus: A Case Report on Successful Treatment Under Intracranial Pressure Monitoring with Bilateral Ventriculoperitoneal Shunts.

    Science.gov (United States)

    Pandey, Sajan; Jin, Yi; Gao, Liang; Zhou, Cheng Cheng; Cui, Da Ming

    2017-03-01

    Negative-pressure hydrocephalus (NegPH), a very rare condition of unknown etiology and optimal treatment, usually presents postneurosurgery with clinical and imaging features of hydrocephalus, but with negative cerebrospinal fluid pressure. We describe a NegPH case of -3 mm Hg intracranial pressure that was successfully treated to achieve 5 mm Hg under continuous intracranial pressure monitoring with horizontal positioning, head down and legs elevated to 10°-15°, neck wrapping for controlled venous drainage, chest and abdomen bandages, infusion of 5% dextrose fluid to lower plasma osmolarity (Na + , 130-135 mmol/L), daily cerebrospinal fluid drainage >200 mL, and arterial blood gas partial pressure of carbon dioxide >40 mm Hg. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Disappearance of Intracranial Extradural Hematomas: Role of Diastatic Cranial Fracture and Intracranial Pressure - An Institutional Experience

    Science.gov (United States)

    Bhat, Abdul Rashid; Kirmani, Altaf Rehman; Wani, Mohammed Afzal

    2018-01-01

    Context: The intracranial extradural hematoma (EDH) occupies space and creates a mass effect on the brain but the tenacious-adhesions of dura to the inner table of skull counters this effect. The intracranial pressure also pushes the hematoma back while it is held by dural tensile-force. Aims: The exploitation of a diastatic fracture, overlying an EDH, by the intracranial pressures to decompress a hematoma out of extradural space into subgaleal/subperiosteal space without surgical intervention. Settings and Design: In a period of 15 years, a group of 11 patients among 729 EDHs were managed conservatively. Materials and Methods: The retrospective study of 11 EDH patients was conducted in the Department of Neurosurgery from January 2000 to December 2014 in 15 years. Statistical Analysis Used: The statistical law of variance was used as applicable. Results: Analysis of spontaneous disappearance of intracranial EDH among 11 patients revealed that only 1.5% (11/729) EDHs resolved conservatively. The most cases (63.6%) were children and the youngest being 9 months old. All the patients had a diastatic fracture overlying-EDH and were fully conscious. The cause of head injury in most was the fall from height. The hospital stay ranged from 2 to 4 days. All the patients had a good recovery at the time of discharging. Conclusion: The trial of the conservative or spontaneous disappearance of an EDH through a diastatic fracture into the subgaleal space is similar to burr-hole drainage without surgical intervention but depends upon the neurological status, the intracranial pressure of the patient, and the availability of all the modern neurosurgical gadgets. PMID:29682037

  20. Model-Based, Noninvasive Monitoring of Intracranial Pressure

    Science.gov (United States)

    2013-07-01

    vasoactive medication drip rates and ventilator settings, nursing progress notes, discharge summaries, radiology reports, provider order entry data...the interaction of intracranial pressure and cerebral hemodynamics . Journal of Applied Physiology 82(4):1256-1269, 1997. [5] M Saeed, M Villarroel, AT

  1. The Visual Impairment Intracranial Pressure Syndrome in Long Duration NASA Astronauts: An Integrated Approach

    Science.gov (United States)

    Otto, C. A.; Norsk, P.; Shelhamer, M. J.; Davis, J. R.

    2015-01-01

    The Visual Impairment Intracranial Pressure (VIIP) syndrome is currently NASA's number one human space flight risk. The syndrome, which is related to microgravity exposure, manifests with changes in visual acuity (hyperopic shifts, scotomas), changes in eye structure (optic disc edema, choroidal folds, cotton wool spots, globe flattening, and distended optic nerve sheaths). In some cases, elevated cerebrospinal fluid pressure has been documented postflight reflecting increased intracranial pressure (ICP). While the eye appears to be the main affected end organ of this syndrome, the ocular affects are thought to be related to the effect of cephalad fluid shift on the vascular system and the central nervous system. The leading hypotheses for the development of VIIP involve microgravity induced head-ward fluid shifts along with a loss of gravity-assisted drainage of venous blood from the brain, both leading to cephalic congestion and increased ICP. Although not all crewmembers have manifested clinical signs or symptoms of the VIIP syndrome, it is assumed that all astronauts exposed to microgravity have some degree of ICP elevation in-flight. Prolonged elevations of ICP can cause long-term reduced visual acuity and loss of peripheral visual fields, and has been reported to cause mild cognitive impairment in the analog terrestrial population of Idiopathic Intracranial Hypertension (IIH). These potentially irreversible health consequences underscore the importance of identifying the factors that lead to this syndrome and mitigating them.

  2. Poor correlation between intracranial pressure and intraocular pressure by hand-held tonometry

    Directory of Open Access Journals (Sweden)

    Golan S

    2013-06-01

    Full Text Available Shani Golan,1 Shimon Kurtz,1 Daphna Mezad-Koursh,1 Michael Waisbourd,1 Anat Kesler,1 Pinchas Halpern2 1Departments of Ophthalmology, Tel Aviv Sourasky Medical Center, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 2Emergency Medicine, Tel Aviv Sourasky Medical Center, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Purpose: The aim of this study is to provide data on the controversial issue of whether handheld measurements of intraocular pressure (IOP are capable of accurately predicting elevated intracranial pressure (ICP in patients undergoing lumbar puncture (LP. Methods: All patients over the age of 18 years who underwent an LP in the emergency or neurological departments at the Tel Aviv Medical center for any reason between October 2007 and July 2010 were eligible to participate in this prospective observational pilot study. IOP was measured with the Tono-Pen XL while patients were in the supine position before undergoing LP. ICP was measured in the lateral recumbent position. ICP and bilateral IOP were measured, and the mean and maximum values of IOP were calculated. The association between ICP and each one of the four IOP measures was evaluated by the Pearson correlation coefficient. Results: Twenty-four patients (mean age 37.8 ± 15.8 years, ten males and 14 females were enrolled. The reasons for their requiring an LP were headache (19/24 patients, evaluation for hemiparesis (2/24, cognitive deterioration (1/24, and seizures (2/24. Nine had elevated mean opening pressure (>20 cm H2O, six had an elevated mean IOP (>20 mmHg, and four of these six also had an elevated opening pressure. There was no significant correlation between the ICP measurements and any of the IOP measurements. Conclusion: Handheld ocular tonometry has poor sensitivity and specificity for the prediction of increased ICP and is not an effective tool for screening for ICP in the ED or in the

  3. Chronic fatigue syndrome and idiopathic intracranial hypertension: Different manifestations of the same disorder of intracranial pressure?

    Science.gov (United States)

    Higgins, J Nicholas P; Pickard, John D; Lever, Andrew M L

    2017-08-01

    Though not discussed in the medical literature or considered in clinical practice, there are similarities between chronic fatigue syndrome and idiopathic intracranial hypertension (IIH) which ought to encourage exploration of a link between them. The cardinal symptoms of each - fatigue and headache - are common in the other and their multiple other symptoms are frequently seen in both. The single discriminating factor is raised intracranial pressure, evidenced in IIH usually by the sign of papilloedema, regarded as responsible for the visual symptoms which can lead to blindness. Some patients with IIH, however, do not have papilloedema and these patients may be clinically indistinguishable from patients with chronic fatigue syndrome. Yet IIH is rare, IIH without papilloedema (IIHWOP) seems rarer still, while chronic fatigue syndrome is common. So are the clinical parallels spurious or is there a way to reconcile these conflicting observations? We suggest that it is a quirk of clinical measurement that has created this discrepancy. Specifically, that the criteria put in place to define IIH have led to a failure to appreciate the existence, clinical significance or numerical importance of patients with lower level disturbances of intracranial pressure. We argue that this has led to a grossly implausible distortion of the epidemiology of IIH such that the milder form of the illness (IIHWOP) is seen as less common than the more severe and that this would be resolved by recognising a connection with chronic fatigue syndrome. We hypothesise, therefore, that IIH, IIHWOP, lesser forms of IIH and an undetermined proportion of chronic fatigue cases are all manifestations of the same disorder of intracranial pressure across a spectrum of disease severity, in which this subset of chronic fatigue syndrome would represent the most common and least severe and IIH the least common and most extreme. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Vasomotor origin of intracranial pressure waves in hydrocephalic infants

    Energy Technology Data Exchange (ETDEWEB)

    Barritault, L; Rimbert, J N; Hirsch, J F; Pierr-Kahn, A; Lacombe, J; Zouaoui, A; Mises, J; Gabersek, V

    1980-12-01

    By measuring cerebral blood volume (CBV) and intracranial pressure (ICP) variations at the same running time during sleep, it has been demonstrated that the ICP wave which appears during the REM sleep in hydrocephalic infants is produced by intracerebral vaso-dilatation. Nine infants with stabilized hydrocephalus were investigated by non-invasive means: REM phases were distinguished with the usual polysomnographic electrodes. Intracranial pressure was measured with a fontanel palpation transducer and CBV variations were obtained by recording /sup 99/sup(m)Tc activity at the head level after in vivo labelling of red cells with /sup 99/sup(m)Tc-pertechnetate. The time activity curves, obtained from regions of interest and selected on the sequential radioisotope images, show that an increased ICP wave, occurring during the REM period, is related to a simultaneous increase in the blood volume, limited to the cerebral sector and not to the area of the external carotid artery.

  5. Dynamics of inner ear pressure change caused by intracranial pressure manipulation in the guinea pig

    NARCIS (Netherlands)

    Thalen, EO; Wit, HP; Segenhout, JM; Albers, FWJ

    Previous studies have shown that pressure changes in the cerebrospinal fluid compartment are transmitted to the inner ear. The main route for pressure transfer is the cochlear aqueduct, about which little is known with regard to its dynamic properties. In the present study, sudden intracranial

  6. Visual Impairment/Increased Intracranial Pressure (VIIP): Layman's Summary

    Science.gov (United States)

    Fogarty, Jennifer

    2011-01-01

    To date NASA has documented that seven long duration astronauts have experienced in-flight and post-flight changes in vision and eye anatomy including degraded distant vision, swelling of the back of the eye, and changes in the shape of the globe. We have also documented in a few of these astronauts post-flight, increases in the pressure of the fluid that surrounds the brain and spinal cord. This is referred to as increased intracranial pressure (ICP). The functional and anatomical changes have varied in severity and duration. In the post-flight time period, some individuals have experienced a return to a pre-flight level of visual function while others have experienced changes that remain significantly altered compared to pre-flight. In addition, the increased ICP also persists in the post-flight time period. Currently, the underlying cause or causes of these changes is/are unknown but the spaceflight community at NASA suspects that the shift of blood toward the head and the changes in physiology that accompany it, such as increased intracranial pressure, play a significant role.

  7. MRI evidence for preserved regulation of intracranial pressure in patients with cerebral arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Meinel, Felix G.; Fischer, Judith; Pomschar, Andreas; Wöhrle, Natalie; Koerte, Inga K.; Steffinger, Denise [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr. 15, 81377 Munich (Germany); Laubender, Rüdiger P. [Institute of Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Muacevic, Alexander [European Cyberknife Center Munich, 81377 Munich (Germany); Reiser, Maximilian F. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr. 15, 81377 Munich (Germany); Alperin, Noam [Department of Radiology, Miller School of Medicine, University of Miami, Miami, FL 33136 (United States); Ertl-Wagner, Birgit, E-mail: birgit.ertl-wagner@med.uni-muenchen.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr. 15, 81377 Munich (Germany)

    2014-08-15

    Purpose: The purpose of this study was to investigate intracranial pressure and associated hemo- and hydrodynamic parameters in patients with cerebral arteriovenous malformations AVMs. Methods: Thirty consecutive patients with arteriovenous malformations (median age 38.7 years, 27/30 previously treated with radiosurgery) and 30 age- and gender-matched healthy controls were investigated on a 3.0 T MR scanner. Nidus volume was quantified on dynamic MR angiography. Total arterial cerebral blood flow (tCBF), venous outflow as well as aqueductal and craniospinal stroke volumes were obtained using velocity-encoded cine-phase contrast MRI. Intracranial volume change during the cardiac cycle was calculated and intracranial pressure (ICP) was derived from systolic intracranial volume change (ICVC) and pulse pressure gradient. Results: TCBF was significantly higher in AVM patients as compared to healthy controls (median 799 vs. 692 mL/min, p = 0.007). There was a trend for venous flow to be increased in both the ipsilateral internal jugular vein (IJV, 282 vs. 225 mL/min, p = 0.16), and in the contralateral IJV (322 vs. 285 mL/min, p = 0.09), but not in secondary veins. There was no significant difference in median ICP between AVM patients and control subjects (6.9 vs. 8.6 mmHg, p = 0.30) and ICP did not correlate with nidus volume in AVM patients (ρ = −0.06, p = 0.74). There was a significant positive correlation between tCBF and craniospinal CSF stroke volume (ρ = 0.69, p = 0.02). Conclusions: The elevated cerebral blood flow in patients with AVMs is drained through an increased flow in IJVs but not secondary veins. ICP is maintained within ranges of normal and does not correlate with nidus volume.

  8. Single pulse analysis of intracranial pressure for a hydrocephalus implant.

    Science.gov (United States)

    Elixmann, I M; Hansinger, J; Goffin, C; Antes, S; Radermacher, K; Leonhardt, S

    2012-01-01

    The intracranial pressure (ICP) waveform contains important diagnostic information. Changes in ICP are associated with changes of the pulse waveform. This change has explicitly been observed in 13 infusion tests by analyzing 100 Hz ICP data. An algorithm is proposed which automatically extracts the pulse waves and categorizes them into predefined patterns. A developed algorithm determined 88 %±8 % (mean ±SD) of all classified pulse waves correctly on predefined patterns. This algorithm has low computational cost and is independent of a pressure drift in the sensor by using only the relationship between special waveform characteristics. Hence, it could be implemented on a microcontroller of a future electromechanic hydrocephalus shunt system to control the drainage of cerebrospinal fluid (CSF).

  9. Non-invasive assessment of pulsatile intracranial pressure with phase-contrast magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Geir Ringstad

    Full Text Available Invasive monitoring of pulsatile intracranial pressure can accurately predict shunt response in patients with idiopathic normal pressure hydrocephalus, but may potentially cause complications such as bleeding and infection. We tested how a proposed surrogate parameter for pulsatile intracranial pressure, the phase-contrast magnetic resonance imaging derived pulse pressure gradient, compared with its invasive counterpart. In 22 patients with suspected idiopathic normal pressure hydrocephalus, preceding invasive intracranial pressure monitoring, and any surgical shunt procedure, we calculated the pulse pressure gradient from phase-contrast magnetic resonance imaging derived cerebrospinal fluid flow velocities obtained at the upper cervical spinal canal using a simplified Navier-Stokes equation. Repeated measurements of the pulse pressure gradient were also undertaken in four healthy controls. Of 17 shunted patients, 16 responded, indicating high proportion of "true" normal pressure hydrocephalus in the patient cohort. However, there was no correlation between the magnetic resonance imaging derived pulse pressure gradient and pulsatile intracranial pressure (R = -.18, P = .43. Pulse pressure gradients were also similar in patients and healthy controls (P = .26, and did not differ between individuals with pulsatile intracranial pressure above or below established thresholds for shunt treatment (P = .97. Assessment of pulse pressure gradient at level C2 was therefore not found feasible to replace invasive monitoring of pulsatile intracranial pressure in selection of patients with idiopathic normal pressure hydrocephalus for surgical shunting. Unlike invasive, overnight monitoring, the pulse pressure gradient from magnetic resonance imaging comprises short-term pressure fluctuations only. Moreover, complexity of cervical cerebrospinal fluid flow and -pulsatility at the upper cervical spinal canal may render the pulse pressure gradient a poor surrogate

  10. Biotelemetric Wireless Intracranial Pressure Monitoring: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Mohammad H. Behfar

    2015-01-01

    Full Text Available Assessment of intracranial pressure (ICP is of great importance in management of traumatic brain injuries (TBIs. The existing clinically established ICP measurement methods require catheter insertion in the cranial cavity. This increases the risk of infection and hemorrhage. Thus, noninvasive but accurate techniques are attractive. In this paper, we present two wireless, batteryless, and minimally invasive implantable sensors for continuous ICP monitoring. The implants comprise ultrathin (50 μm flexible spiral coils connected in parallel to a capacitive microelectromechanical systems (MEMS pressure sensor. The implantable sensors are inductively coupled to an external on-body reader antenna. The ICP variation can be detected wirelessly through measuring the reader antenna’s input impedance. This paper also proposes novel implant placement to improve the efficiency of the inductive link. In this study, the performance of the proposed telemetry system was evaluated in a hydrostatic pressure measurement setup. The impact of the human tissues on the inductive link was simulated using a 5 mm layer of pig skin. The results from the in vitro measurement proved the capability of our developed sensors to detect ICP variations ranging from 0 to 70 mmHg at 2.5 mmHg intervals.

  11. Cerebral blood volume changes in cats with acute increased intracranial pressure

    International Nuclear Information System (INIS)

    Kondo, Takashi; Kano, Mitsumasa; Ikeda, Takuya.

    1984-01-01

    We measured the changes in cerebral blood volume in cats with increased intracranial pressure with a high-speed CT scanner, employing contrast effects by the iodine agent. In acute increased intracranial pressure caused by raising the extradural pressure by 20 mmHg, cerebral blood volume showed a significant decrease by 32% in comparison with that at normal intracranial pressure. There was also a tendency that a decline of iodine was delayed with time at increased intracranial pressure than that at normal pressure. This was supposed to be a delay of cerebral circulation due to venous congestion. This experimental model and measuring method provide the changes in CBV in the same individual without any tedious procedure, and therefore this is a reliable method with respect to precision. (author)

  12. Intracranial Pressure Is a Determinant of Sympathetic Activity

    Directory of Open Access Journals (Sweden)

    Eric A. Schmidt

    2018-02-01

    Full Text Available Intracranial pressure (ICP is the pressure within the cranium. ICP rise compresses brain vessels and reduces cerebral blood delivery. Massive ICP rise leads to cerebral ischemia, but it is also known to produce hypertension, bradycardia and respiratory irregularities due to a sympatho-adrenal mechanism termed Cushing response. One still unresolved question is whether the Cushing response is a non-synaptic acute brainstem ischemic mechanism or part of a larger physiological reflex for arterial blood pressure control and homeostasis regulation. We hypothesize that changes in ICP modulates sympathetic activity. Thus, modest ICP increase and decrease were achieved in mice and patients with respectively intra-ventricular and lumbar fluid infusion. Sympathetic activity was gauged directly by microneurography, recording renal sympathetic nerve activity in mice and muscle sympathetic nerve activity in patients, and gauged indirectly in both species by heart-rate variability analysis. In mice (n = 15, renal sympathetic activity increased from 29.9 ± 4.0 bursts.s−1 (baseline ICP 6.6 ± 0.7 mmHg to 45.7 ± 6.4 bursts.s−1 (plateau ICP 38.6 ± 1.0 mmHg and decreased to 34.8 ± 5.6 bursts.s−1 (post-infusion ICP 9.1 ± 0.8 mmHg. In patients (n = 10, muscle sympathetic activity increased from 51.2 ± 2.5 bursts.min−1 (baseline ICP 8.3 ± 1.0 mmHg to 66.7 ± 2.9 bursts.min−1 (plateau ICP 25 ± 0.3 mmHg and decreased to 58.8 ± 2.6 bursts.min−1 (post-infusion ICP 14.8 ± 0.9 mmHg. In patients 7 mmHg ICP rise significantly increases sympathetic activity by 17%. Heart-rate variability analysis demonstrated a significant vagal withdrawal during the ICP rise, in accordance with the microneurography findings. Mice and human results are alike. We demonstrate in animal and human that ICP is a reversible determinant of efferent sympathetic outflow, even at relatively low ICP levels. ICP is a biophysical stress related to the forces within the brain. But ICP

  13. Quantification of abnormal intracranial pressure waves and isotope cisternography for diagnosis of occult communicating hydrocephalus

    International Nuclear Information System (INIS)

    Cardoso, E.R.; Piatek, D.; Del Bigio, M.R.; Stambrook, M.; Sutherland, J.B.

    1989-01-01

    Nineteen consecutive patients with suspected occult communicating hydrocephalus were investigated by means of clinical evaluation, neuropsychological testing, isotope cisternography, computed tomography scanning, and continuous intracranial pressure monitoring. Semi-quantitative grading systems were used in the evaluation of the clinical, neuropsychological, and cisternographic assessments. Clinical examination, neuropsychological testing, and computed tomography scanning were repeated 3 months after ventriculoperitoneal shunting. All patients showed abnormal intracranial pressure waves and all improved after shunting. There was close correlation between number, peak, and pulse pressures of B waves and the mean intracranial pressure. However, quantification of B waves by means of number, frequency, and amplitude did not help in predicting the degree of clinical improvement postshunting. The most sensitive predictor of favorable response to shunting was enlargement of the temporal horns on computed tomography scan. Furthermore, the size of temporal horns correlated with mean intracranial pressure. There was no correlation between abnormalities on isotope cisternography and clinical improvement

  14. Raised intracranial pressure: What it is and how to recognise it

    African Journals Online (AJOL)

    This article presents an approach to raised intracranial pressure (ICP) constructed in a question-answer fashion. ... involves shifts of CSF and venous blood out .... by changes in posture, position and .... ICP can be measured by a number of.

  15. MRI measurements of intracranial pressure in the upright posture: The effect of the hydrostatic pressure gradient.

    Science.gov (United States)

    Alperin, Noam; Lee, Sang H; Bagci, Ahmet M

    2015-10-01

    To add the hydrostatic component of the cerebrospinal fluid (CSF) pressure to magnetic resonance imaging (MRI)-derived intracranial pressure (ICP) measurements in the upright posture for derivation of pressure value in a central cranial location often used in invasive ICP measurements. Additional analyses were performed using data previously collected from 10 healthy subjects scanned in supine and sitting positions with a 0.5T vertical gap MRI scanner (GE Medical). Pulsatile blood and CSF flows to and from the brain were quantified using cine phase-contrast. Intracranial compliance and pressure were calculated using a previously described method. The vertical distance between the location of the CSF flow measurement and a central cranial location was measured manually in the mid-sagittal T1 -weighted image obtained in the upright posture. The hydrostatic pressure gradient of a CSF column with similar height was then added to the MR-ICP value. After adjustment for the hydrostatic component, the mean ICP value was reduced by 7.6 mmHg. Mean ICP referenced to the central cranial level was -3.4 ± 1.7 mmHg compared to the unadjusted value of +4.3 ± 1.8 mmHg. In the upright posture, the hydrostatic pressure component needs to be added to the MRI-derived ICP values for compatibility with invasive ICP at a central cranial location. © 2015 Wiley Periodicals, Inc.

  16. Clinical evaluation of a new intracranial pressure monitoring device.

    Science.gov (United States)

    Stendel, R; Heidenreich, J; Schilling, A; Akhavan-Sigari, R; Kurth, R; Picht, T; Pietilä, T; Suess, O; Kern, C; Meisel, J; Brock, M

    2003-03-01

    Continuous monitoring of intracranial pressure (ICP) still plays a key role in the management of patients at risk from intracranial hypertension. Numerous ICP-measuring devices are available. The aim of the present study was to investigate the clinical characteristics and the magnetic resonance imaging (MRI) compatibility of the recently developed Neurovent-P(REHAU AG+CO, REHAU, Germany) ICP monitoring device. In a prospective two-center study, a total of 98 patients with severe head injury, subarachnoid haemorrhage, intracerebral haemorrhage, and non-traumatic brain edema underwent intraparenchymal monitoring of ICP using the Neurovent-P. A control group comprising 50 patients underwent implantation of the Camino-OLM-110-4B ICP monitor. The zero drift of the probes was determined before and after the ICP recording period. Technical and medical complications were documented. The MRI compatibility of the Neurovent-P ICP probe was investigated by evaluating artifacts caused by the probe, probe function and temperature changes during MRI, and probe movement caused by the magnetic field. The mean zero drift was 0.2+/-0.41 mmHg (maximum 3 mmHg) for the Neurovent-P ICP probes and 0.4+/-0.57 mmHg (maximum 12 mmHg) for the Camino-OLM-110-4B ICP probes. No significant correlation was identified between the extent of zero drift following the removal of the probes and the length of monitoring. Intraparenchymal haemorrhage spatially related to the probe occurred in 1 out of 50 (2%) patients with a Camino-OLM-110-4B probe and in 1 out of 98 (1%) with a Neurovent-P. Damage of the probe due to kinking or overextension of the cable or glass fiber occurred in 4 of the 50 (8%) Camino-OLM-110-4B ICP probes and in 5 of the 98 (5%) Neurovent-P probes. On T2-weighted MR images, the Neurovent-P ICP probe induced only small artifacts with very good discrimination of the surrounding tissue. On T1-weighted MR images, there was a good imaging quality but artifact-related local disturbances

  17. Non-Invasive Ultrasonic Diagnosing and Monitoring of Intracranial Pressure/Volume

    Science.gov (United States)

    2001-10-01

    Libraria, Padoue (Italia) 53 37. Guinduiz G, Viernstein LW (1979). Intracranial pressure in the normal monkey while awake and asleep. J Neurosurg 51, 206...cerebral microcirculation of awake rabbits. Heart Circ Physiol 23, H67-H71 46. Hyndman BW, Kitney RI, Sayers BM (1971). Spontaneous rhythms in...intracranial pressure monitoring. Exclusion criteria: patients with wounds, scars or a craniotomy overlying the optimal window for transintracranial

  18. Intracranial subdural hematomas with elevated rivaroxaban concentration and subsequently detected spinal subdural hematoma: A case report.

    Science.gov (United States)

    Yamaguchi, Yoshitaka; Koga, Masatoshi; Matsuki, Takayuki; Hino, Tenyu; Yokota, Chiaki; Toyoda, Kazunori

    2016-07-01

    A 79-year-old lean man with a height of 157cm and weight of 42kg (body mass index, 17.2kg/m(2)) receiving rivaroxaban developed an intracranial subdural hematoma and was treated conservatively. Because he had a reduced creatinine clearance of 44mL/min, his dosage of rivaroxaban was reduced from 15 to 10mg daily according to official Japanese prescribing information. However, he developed bilateral intracranial subdural hematomas 2weeks later. Plasma rivaroxaban concentration on anti-factor Xa chromogenic assay was elevated at 301ng/mL, suggesting excessive accumulation. He underwent burr hole drainage and resumed anticoagulation with warfarin. Subsequently, he developed a lumbosacral hematoma. He was treated conservatively and discharged without neurological sequelae. The main cause of the increased concentration of rivaroxaban was believed to be his older age and low body weight. The etiology of the spinal hematoma was suspected to be the migration of intracranial hematoma to the spinal subdural space. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Telemetric intra-cranial pressure monitoring: clinical and financial considerations.

    Science.gov (United States)

    Barber, James M; Pringle, Catherine J; Raffalli-Ebezant, Helen; Pathmanaban, Omar; Ramirez, Roberto; Kamaly-Asl, Ian D

    2017-06-01

    Intracranial pressure (ICP) measurement is an important diagnostic tool in Neurosurgery. Until relatively recently, conventional monitoring has required that subjects be admitted to a hospital bed and the device is only able to be left in-situ for limited periods of time. We have evaluated a Telemetric ICP monitoring system that has been proven, by several other groups worldwide, to permit rapid, repeated and prolonged ICP measurement, in multiple environments. In our unit, 4 patients have been implanted to-date, between the ages of 4 and 16, manifesting a wide range of complex neurosurgical conditions. The sensors have been left in-situ for between 460 and 632 days. There have been no clinical complications and the system has been universally well tolerated. Clinical events, costs and patient experience were all assessed prior to and following implantation. Overall, there was a significant reduction in associated admissions (44.3%), imaging requirements (72.5%) and costs (50.0%). Subjective feedback from both the patients (where possible) and their families was overwhelmingly positive, partly due to (a) the system's ease of use, (b) its ability to reduce the number of admissions/tests required and (c) the facility for rapid measurement of ICP that permitted on-the-spot reassurance of concerns. Additionally, the ability to monitor ICP at home and/or whilst ambulant, has provided measurements that were hitherto inaccessible to our team, facilitating all the potential benefits that analysis of such information would provide. Indeed, we have seen the resultant management in each case has been completely altered by the availability of this data, reaffirming that the importance of being able to obtain it should not be underestimated. The combination of both this and the ability to markedly improve patient experience, along with generating significant cost-savings, lead the authors to suggest that the implantation of this system should be strongly considered in selected

  20. Intracranial pressure following complete removal of a small demarcated brain tumor

    DEFF Research Database (Denmark)

    Andresen, Morten; Juhler, Marianne

    2014-01-01

    OBJECTIVES: Current published normal values for intracranial pressure (ICP) are extrapolated from lumbar CSF pressure measurements and ICP measurements in patients treated for CSF pressure disorders. There is an emerging agreement that true normal ICP values are needed for diagnostic and therapeu...... and the ICP target range in hydrocephalus treatment....

  1. Headaches caused by decreased intracranial pressure: diagnosis and management.

    Science.gov (United States)

    Mokri, Bahram

    2003-06-01

    More patients with spontaneous intracranial hypotension are now being diagnosed, and it is realized that most cases result from spontaneous cerebrospinal fluid leaks. A broader clinical and imaging spectrum of the disorder is recognized. This paper reviews new insights into the variability of clinical manifestations, imaging features, etiological factors, anatomy of leaks, and implications of these in patient management. Spontaneous intracranial hypotension should not be equated with post-lumbar puncture headaches. In a substantial minority of patients, headaches are not orthostatic and may mimic other types of headache. Additional diverse neurological manifestations may dominate the clinical picture and patients may occasionally have no headache at all. Reports on unusual presentations of the disorder continue to appear in the literature. Furthermore, additional imaging features of cerebrospinal fluid leaks are recognized. High-flow and slow-flow leaks may present diagnostic challenges, and require modification of diagnostic studies aimed at locating the site of the leak. Stigmata of connective tissue abnormality, especially abnormalities of fibrillin and elastin, are seen in a notable minority of patients, pointing to weakness of the dural sac as one of the etiological factors. After treatment of spontaneous intracranial hypotension, surgically or by epidural blood patch, a rebound and self-limiting intracranial hypertension may sometimes develop. In the past decade, interest in spontaneous intracranial hypotension has been rekindled, with a substantial growth of knowledge on various aspects of the disorder. We are in the learning phase, and new information will probably appear in the future, with notable diagnostic and therapeutic implications.

  2. Increased Intracranial Pressure in a Boy with Gorham-Stout Disease

    Directory of Open Access Journals (Sweden)

    Manisha K. Patel

    2016-04-01

    Full Text Available Gorham-Stout disease (GSD, also known as vanishing bone disease, is a rare disorder, which most commonly presents in children and young adults and is characterized by an excessive proliferation of lymphangiomatous tissue within the bones. This lymphangiomatous proliferation often affects the cranium and, due to the proximate location to the dura surrounding cerebrospinal fluid (CSF spaces, can result in CSF leaks manifesting as intracranial hypotension with clinical symptoms to include orthostatic headache, nausea, and vertigo. We present the case of a boy with GSD and a known history of migraine headaches who presented with persistent headaches due to increased intracranial pressure. Although migraine had initially been suspected, he was eventually diagnosed with intracranial hypertension after developing ophthalmoplegia and papilledema. We describe the first known instance of successful medical treatment of increased intracranial pressure in a patient with GSD.

  3. Ophthalmic changes and increased intracranial pressure associated with long duration spaceflight: An emerging understanding

    Science.gov (United States)

    Marshall-Bowman, Karina; Barratt, Michael R.; Gibson, C. Robert

    2013-06-01

    For many years, there have been anecdotal reports of vision changes by astronauts following short and long-duration spaceflight. Much of this was attributed to hyperopic shifts related to the age of the flying population. However, it has recently been recognized that vision changes are actually quite common in astronauts and are associated with a constellation of findings including elevated intracranial pressure, optic disc edema, globe flattening, optic nerve sheath thickening, hyperopic shifts and retinal changes. With advanced imaging modalities available on the ground along with the fidelity of in-flight diagnostic capabilities previously unavailable, information on this newly recognized syndrome is accumulating. As of this writing, 11 cases of visual impairment experienced by astronauts during missions on-board the International Space Station (ISS) have been documented and studied. Although the exact mechanisms of the vision changes are unknown, it is hypothesized that increased intracranial pressure (ICP) is a contributing factor. Microgravity is the dominant cause of many physiological changes during spaceflight and is thought to contribute significantly to the observed ophthalmic changes. However, several secondary factors that could contribute to increased ICP and vision changes in spaceflight have been proposed. Possible contributors include microgravity-induced cephalad fluid shift, venous obstruction due to microgravity-induced anatomical shifts, high levels of spacecraft cabin carbon dioxide, heavy resistive exercise, and high sodium diet. Individual susceptibility to visual impairment is not fully understood, though a demographic of affected astronauts is emerging. This paper describes the current understanding of this newly recognized syndrome, presents data from 11 individual cases, and discusses details of potential contributing factors. The occurrence of visual changes in long duration missions in microgravity is one of the most significant

  4. CT changes in children with drained hydrocephalus and intermittently raised intracranial pressure

    International Nuclear Information System (INIS)

    Schmidt, H.; Korinthenberg, R.; Erlemann, R.; Lengerke, H.J. von; Muenster Univ.

    1987-01-01

    Seven children with drained hydrocephalus are described who showed increasingly severe and frequent episodes of intermittently raised intracranial pressure. CT examinations during symptom-free intervals, or after conservative treatment, showed collapsed slit-like ventricles. Examination during attacks of raised pressure showed relative dilatation of the ventricles as compared with earlier examinations. Children with ventricular shunts of long duration may develop a shunt-dependent syndrome; CT may show normal or narrow ventricles and this does not exclude the possibility of a rise of intracranial pressure. These findings may help in making the diagnosis by means of CT without any further invasive procedure. (orig.) [de

  5. Telemetric implantable pressure sensor for short- and long-term monitoring of intracranial pressure.

    Science.gov (United States)

    Frischholz, M; Sarmento, L; Wenzel, M; Aquilina, K; Edwards, R; Coakham, H B

    2007-01-01

    Patients with hydrocephalus, idiopathic intracranial hypertension and head injury frequently require monitoring of intracranial pressure (ICP) and may need repeated episodes of monitoring months or years apart. The gold standard for measurement of ICP remains the external ventricular catheter. This is a fluid-filled catheter transducer system that allows regular recalibration and correction of zero drift by its position relative to a fixed anatomical reference. It also allows drainage of cerebrospinal fluid (CSF), providing a means of lowering the ICP. Several catheter tip transducer systems are currently in clinical use, including using strain gauges or fiber-optical pressure sensing techniques. In these devices, zero drift and calibration cannot be checked in vivo. All the ICP monitoring devices in current clinical use require a physical connection between the brain and the external environment. This is a source of infection and limits the duration of monitoring. A number of telemetric monitoring devices, in which data is in some way transmitted transcutaneously, have been developed over the last twenty years, but significant technical problems have precluded their use in routine clinical practice. All current ICP monitors are temporary percutaneous implanted devices. Placement of these devices carries significant morbidity, particularly infection. Patients undergoing repeated monitoring require multiple surgical procedures. Apart from decreasing the risk of infection in patients with severe head injury, the clinical value of an accurate telemetric ICP monitoring system which maintains its reliability over a long period of implantation is high.

  6. The baseline pressure of intracranial pressure (ICP) sensors can be altered by electrostatic discharges.

    Science.gov (United States)

    Eide, Per K; Bakken, André

    2011-08-22

    The monitoring of intracranial pressure (ICP) has a crucial role in the surveillance of patients with brain injury. During long-term monitoring of ICP, we have seen spontaneous shifts in baseline pressure (ICP sensor zero point), which are of technical and not physiological origin. The aim of the present study was to explore whether or not baseline pressures of ICP sensors can be affected by electrostatics discharges (ESD's), when ESD's are delivered at clinically relevant magnitudes. We performed bench-testing of a set of commercial ICP sensors. In our experimental setup, the ICP sensor was placed in a container with 0.9% NaCl solution. A test person was charged 0.5-10 kV, and then delivered ESD's to the sensor by touching a metal rod that was located in the container. The continuous pressure signals were recorded continuously before/after the ESD's, and the pressure readings were stored digitally using a computerized system A total of 57 sensors were tested, including 25 Codman ICP sensors and 32 Raumedic sensors. When charging the test person in the range 0.5-10 kV, typically ESD's in the range 0.5-5 kV peak pulse were delivered to the ICP sensor. Alterations in baseline pressure ≥ 2 mmHg was seen in 24 of 25 (96%) Codman sensors and in 17 of 32 (53%) Raumedic sensors. Lasting changes in baseline pressure > 10 mmHg that in the clinical setting would affect patient management, were seen frequently for both sensor types. The changes in baseline pressure were either characterized by sudden shifts or gradual drifts in baseline pressure. The baseline pressures of commercial solid ICP sensors can be altered by ESD's at discharge magnitudes that are clinically relevant. Shifts in baseline pressure change the ICP levels visualised to the physician on the monitor screen, and thereby reveal wrong ICP values, which likely represent a severe risk to the patient.

  7. Inner ear pressure changes following square wave intracranial or ear canal pressure manipulation in the same guinea pig

    NARCIS (Netherlands)

    Thalen, E; Wit, H; Segenhout, H; Albers, F

    Inner ear pressure was measured in scala tympani with a micropipette during square wave pressure manipulation of the intracranial compartment and, subsequently, of the external ear canal (EEC) in the same guinea pig. As expected, the combination of the cochlear aqueduct and the inner ear behaves as

  8. Visual evoked potentials show strong positive association with intracranial pressure in patients with cryptococcal meningitis

    Directory of Open Access Journals (Sweden)

    Marcelo Adriano da Cunha Silva Vieira

    2015-04-01

    Full Text Available Objective : To verify the relationship between intracranial pressure and flash visual evoked potentials (F-VEP in patients with cryptococcal meningitis. Method The sample included adults diagnosed with cryptococcal meningitis admitted at a reference hospital for infectious diseases. The patients were subjected to F-VEP tests shortly before lumbar puncture. The Pearson’s linear correlation coefficient was calculated and the linear regression analysis was performed. Results : Eighteen individuals were subjected to a total of 69 lumbar punctures preceded by F-VEP tests. At the first lumbar puncture performed in each patient, N2 latency exhibited a strong positive correlation with intracranial pressure (r = 0.83; CI = 0.60 - 0.94; p < 0.0001. The direction of this relationship was maintained in subsequent punctures. Conclusion : The intracranial pressure measured by spinal tap manometry showed strong positive association with the N2 latency F-VEP in patients with cryptococcal meningitis.

  9. Continuous monitoring of intracranial pressure after endoscopic third ventriculostomy in the management of CSF shunt failure.

    Science.gov (United States)

    Elgamal, E A

    2010-04-01

    The effectiveness of continuous intracranial pressure (ICP) monitoring in the adaptation period, after endoscopic third ventriculostomy (ETV), and removal of the failed shunt in the management of CSF shunt failure is assessed. Nine patients with active hydrocephalus presenting with CSF shunt obstruction or infection were managed by ETV, removal of the shunt and insertion of an external ventricular drain (EVD) containing an ICP sensor for the purpose of postoperative monitoring of the ICP, and intermittent drainage of CSF. Patient ages ranged from 8 months to 24 years, and six of them were females. Hydrocephalus was obstructive in seven patients, and multiloculated in two. Six patients had an ventriculoperitoneal shunt (VPS), one with a bilateral VPS, one patient had a ventriculoatrial shunt, and one had a VPS and cystoperitoneal shunt (CPS). Shunt failure was caused by obstruction in six patients and infection in three. The post-operative ICP monitoring period ranged from 1-7 days. Intracranial hypertension was persistent in the first day after ETV in 3 patients, and up to 110 mL of CSF were drained to improve its symptoms. ETV was successful in six patients and 3 had permanent VPS. Post-operative continuous ICP monitoring and EVD insertion were very useful in the treatment of CSF shunt failure with ETV. This procedure allowed intermittent CSF drainage, relieving symptoms of elevated ICP, and provided accurate assessment of the success of the ETV and patency of the stoma in the early postoperative days by CT ventriculography and can also be used to install antibiotics in cases of infection.

  10. Increased Intracranial Pressure and Visual Impairment Associated with Long-Duration Spaceflight

    Science.gov (United States)

    Marshall-Bowman, Karina

    2011-01-01

    Although humans have been flying in space since the 1960s, more recent missions have revealed a new suite of physiological adaptations and consequences of space flight. Notably, 60% of long-duration crewmembers (ISS/MIR) and >25% of short-duration (Shuttle) crewmembers have reported subjective degradation in vision (based on debrief comments) (Gibson 2011). Decreased near-visual acuity was demonstrated in 46% of ISS/Mir and 21% of Shuttle crewmembers, resulting in a shift of up to 1-2 diopters in their refractive correction. It is likely that the recently revealed ophthalmic changes have been present since the first days of human space flight, but have been overlooked or attributed to other causations. The reported changes in vision have occurred at various time points throughout missions, with ranging degrees of visual degradation. Although some cases resolved upon return to Earth, several astronauts have not regained preflight visual acuity, indicating that the damage may be permanent. While observing these changes over the years, without other overt symptomology and with the given age range of the flying population, this has largely been attributed to an expected hyperopic shift due to aging. However, the availability of onboard analysis techniques, including visual acuity assessments, retinal imagery, and ultrasounds of the eye and optic nerve tracts, along with more detailed post-flight techniques, has led to the recent recognition of a wider syndrome. Along with vision changes, findings include flattening of the globe, swelling of the optic disc (papilledema), choroidal folds in the retina, swelling of the optic nerve sheath, and visual field defects. It is widely hypothesized that this constellation of findings may be explained by an elevation of intracranial pressure (ICP). Out of the 60% of long-duration astronauts that have reported a subjective degradation in vision, a subset (currently 10 astronauts) have developed this syndrome. The National

  11. Syphilis mimicking idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Yri, Hanne; Wegener, Marianne; Jensen, Rigmor

    2011-01-01

    Idiopathic intracranial hypertension (IIH) is a condition of yet unknown aetiology affecting predominantly obese females of childbearing age. IIH is a diagnosis of exclusion as raised cerebrospinal fluid pressure may occur secondary to numerous other medical conditions. An atypical phenotype or a...... antibiotic treatment, signs and symptoms of elevated intracranial pressure resolved completely. Syphilis is a rare, but very important, differential diagnosis that in this case was clinically indistinguishable from IIH....

  12. Cerebrospinal fluid corticosteroid levels and cortisol metabolism in patients with idiopathic intracranial hypertension: a link between 11beta-HSD1 and intracranial pressure regulation?

    Science.gov (United States)

    Sinclair, Alexandra J; Walker, Elizabeth A; Burdon, Michael A; van Beek, Andre P; Kema, Ido P; Hughes, Beverly A; Murray, Philip I; Nightingale, Peter G; Stewart, Paul M; Rauz, Saaeha; Tomlinson, Jeremy W

    2010-12-01

    The etiology of idiopathic intracranial hypertension (IIH) is unknown. We hypothesized that obesity and elevated intracranial pressure may be linked through increased 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. The aim was to characterize 11β-HSD1 in human cerebrospinal fluid (CSF) secretory [choroid plexus (CP)] and drainage [arachnoid granulation tissue (AGT)] structures, and to evaluate 11β-HSD1 activity after therapeutic weight loss in IIH. We conducted in vitro analysis of CP and AGT and a prospective in vivo cohort study set in two tertiary care centers. Twenty-five obese adult female patients with active IIH were studied, and 22 completed the study. Fasted serum, CSF, and 24-h urine samples were collected at baseline, after 3-month observation, and after a 3-month diet. Changes in urine, serum, and CSF glucocorticoids (measured by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry) after weight loss were measured. 11β-HSD1 and key elements of the glucocorticoid signaling pathway were expressed in CP and AGT. After weight loss (14.2±7.8 kg; Plevels correlated with weight loss (r=-0.512; P=0.018). Therapeutic weight loss in IIH is associated with a reduction in global 11β-HSD1 activity. Elevated 11β-HSD1 may represent a pathogenic mechanism in IIH, potentially via manipulation of CSF dynamics at the CP and AGT. Although further clarification of the functional role of 11β-HSD1 in IIH is needed, our results suggest that 11β-HSD1 inhibition may have therapeutic potential in IIH.

  13. The effects of indomethacin on intracranial pressure and cerebral haemodynamics in patients undergoing craniotomy

    DEFF Research Database (Denmark)

    Rasmussen, Mads; Tankisi, A; Cold, G E

    2004-01-01

    We compared the effects of indomethacin (bolus of 0.2 mg.kg-1 followed by an infusion of 0.2 mg.kg-1.h-1) and placebo on intracranial pressure and cerebral haemodynamics in 30 patients undergoing craniotomy for supratentorial brain tumours under propofol and fentanyl anaesthesia. Indomethacin...

  14. Visual Impairment/Intracranial Pressure Research Clinical Advisory Panel (RCAP) Meeting. [Summary Report

    Science.gov (United States)

    Villarreal, Jennifer

    2014-01-01

    The Visual Impairment/Intracranial Pressure (VIIP) Research and Clinical Advisory Panel convened on December 1, 2014 at the ISS Conference Facility in Houston. The panel members were provided updates to the current clinical cases and treatment plans along with the latest research activities (http://humanresearchroadmap.nasa.gov/Risks/?i=105) and preliminary study results. The following is a summary of this meeting.

  15. Clinical experience with telemetric intracranial pressure monitoring in a Danish neurosurgical center

    DEFF Research Database (Denmark)

    Lilja, Alexander; Andresen, Morten; Hadi, Amer

    2014-01-01

    kinds of hydrocephalus, seven patients had idiopathic intracranial hypertension (IIH) and three patients had normal pressure hydrocephalus (NPH). Fifteen patients had a shunt prior to implantation. Median duration of implantation was 248 (49-666) days and median duration from implantation to last...

  16. The Course of Intracranial Pressure in Traumatic Brain Injury : Relation with Outcome and CT-characteristics

    NARCIS (Netherlands)

    Bremmer, Rosette; de Jong, Bauke M.; Wagemakers, Michiel; Regtien, Joost G.; van der Naalt, Joukje

    One of the predictive factors of outcome in traumatic brain injury is high intracranial pressure (ICP). Recently, the time course of ICP has been described but few data are available on the relation of these ICP profiles and outcome. The aim of this study is to investigate the relation of the time

  17. The Relationship Between Intracranial Pressure and Age-Chasing Age-Related Reference Values

    DEFF Research Database (Denmark)

    Pedersen, Sarah Hornshøj; Lilja-Cyron, Alexander; Andresen, Morten

    2018-01-01

    Background: No true reference values for intracranial pressure (ICP) in humans exist; current values are estimated from measurements in adults who undergo treatment in order to correct ICP. We report ICP values in a "pseudonormal" group of children and adults to examine if age affects ICP. Method...

  18. Evaluation of Intracranial Pressure in Different Body Postures and Disease Entities

    DEFF Research Database (Denmark)

    Andresen, Morten; Hadi, Amer; Juhler, Marianne

    2016-01-01

    We currently do not have sufficient knowledge regarding appropriate boundaries between "normal" and "abnormal" intracranial pressure (ICP) in humans. Our objective in this study was to quantify the effects of postural changes on ICP in normal and ill subjects. As a model for normal patients, we i...

  19. Plateau Waves of Intracranial Pressure and Partial Pressure of Cerebral Oxygen.

    Science.gov (United States)

    Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

    2016-01-01

    This study investigates 55 intracranial pressure (ICP) plateau waves recorded in 20 patients after severe traumatic brain injury (TBI) with a focus on a moving correlation coefficient between mean arterial pressure (ABP) and ICP, called PRx, which serves as a marker of cerebrovascular reactivity, and a moving correlation coefficient between ABP and cerebral partial pressure of oxygen (pbtO2), called ORx, which serves as a marker for cerebral oxygen reactivity. ICP and ICPamplitude increased significantly during the plateau waves, whereas CPP and pbtO2 decreased significantly. ABP, ABP amplitude, and heart rate remained unchanged. In 73 % of plateau waves PRx increased during the wave. ORx showed an increase during and a decrease after the plateau waves, which was not statistically significant. Our data show profound cerebral vasoparalysis on top of the wave and, to a lesser extent, impairment of cerebral oxygen reactivity. The different behavior of the indices may be due to the different latencies of the cerebral blood flow and oxygen level control mechanisms. While cerebrovascular reactivity is a rapidly reacting mechanism, cerebral oxygen reactivity is slower.

  20. Non-invasive estimation of intracranial pressure. MR-based evaluation in children with hydrocephalus

    International Nuclear Information System (INIS)

    Muehlmann, M.; Steffinger, D.; Ertl-Wagner, B.; Koerte, I.K.; Peraud, A.; Lehner, M.; Heinen, F.; Alperin, N.

    2012-01-01

    The intracranial pressure (ICP) is a crucially important parameter for diagnostic and therapeutic decision-making in patients with hydrocephalus. So far there is no standard method to non-invasively assess the ICP. Various approaches to obtain the ICP semi-invasively or non-invasively are discussed and the clinical application of a magnetic resonance imaging (MRI)-based method to estimate ICP (MR-ICP) is demonstrated in a group of pediatric patients with hydrocephalus. Arterial inflow, venous drainage and craniospinal cerebrospinal fluid (CSF) flow were quantified using phase-contrast imaging to derive the MR-ICP. A total of 15 patients with hydrocephalus (n=9 treated with shunt placement or ventriculostomy) underwent MRI on a 3 T scanner applying retrospectively-gated cine phase contrast sequences. Of the patients six had clinical symptoms indicating increased ICP (age 2.5-14.61 years, mean 7.4 years) and nine patients had no clinical signs of elevated ICP (age 2.1-15.9 years; mean 9.8 years; all treated with shunt or ventriculostomy). Median MR-ICP in symptomatic patients was 24.5 mmHg (25th percentile 20.4 mmHg; 75th percentile 44.6 mmHg). Median MR-ICP in patients without acute signs of increased ICP was 9.8 mmHg (25th percentile 8.6 mmHg; 75th percentile 11.4 mmHg). Group differences were significant (p [de

  1. Changes in Cerebral Partial Oxygen Pressure and Cerebrovascular Reactivity During Intracranial Pressure Plateau Waves.

    Science.gov (United States)

    Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

    2015-08-01

    Plateau waves in intracranial pressure (ICP) are frequently recorded in neuro intensive care and are not yet fully understood. To further investigate this phenomenon, we analyzed partial pressure of cerebral oxygen (pbtO2) and a moving correlation coefficient between ICP and mean arterial blood pressure (ABP), called PRx, along with the cerebral oxygen reactivity index (ORx), which is a moving correlation coefficient between cerebral perfusion pressure (CPP) and pbtO2 in an observational study. We analyzed 55 plateau waves in 20 patients after severe traumatic brain injury. We calculated ABP, ABP pulse amplitude (ampABP), ICP, CPP, pbtO2, heart rate (HR), ICP pulse amplitude (ampICP), PRx, and ORx, before, during, and after each plateau wave. The analysis of variance with Bonferroni post hoc test was used to compare the differences in the variables before, during, and after the plateau wave. We considered all plateau waves, even in the same patient, independent because they are separated by long intervals. We found increases for ICP and ampICP according to our operational definitions for plateau waves. PRx increased significantly (p = 0.00026), CPP (p pressure remains stable in ICP plateau waves, while cerebral autoregulatory indices show distinct changes, which indicate cerebrovascular reactivity impairment at the top of the wave. PbtO2 decreases during the waves and may show a slight overshoot after normalization. We assume that this might be due to different latencies of the cerebral blood flow and oxygen level control mechanisms. Other factors may include baseline conditions, such as pre-plateau wave cerebrovascular reactivity or pbtO2 levels, which differ between studies.

  2. Elevated preoperative blood pressures in adult surgical patients are highly predictive of elevated home blood pressures.

    Science.gov (United States)

    Schonberger, Robert B; Nwozuzu, Adambeke; Zafar, Jill; Chen, Eric; Kigwana, Simon; Monteiro, Miriam M; Charchaflieh, Jean; Sophanphattana, Sophisa; Dai, Feng; Burg, Matthew M

    2018-04-01

    Blood pressure (BP) measurement during the presurgical assessment has been suggested as a way to improve longitudinal detection and treatment of hypertension. The relationship between BP measured during this assessment and home blood pressure (HBP), a better indicator of hypertension, is unknown. The purpose of the present study was to determine the positive predictive value of presurgical BP for predicting elevated HBP. We prospectively enrolled 200 patients at a presurgical evaluation clinic with clinic blood pressures (CBPs) ≥130/85 mm Hg, as measured using a previously validated automated upper-arm device (Welch Allyn Vital Sign Monitor 6000 Series), to undergo daily HBP monitoring (Omron Model BP742N) between the index clinic visit and their day of surgery. Elevated HBP was defined, per American Heart Association guidelines, as mean systolic HBP ≥135 mm Hg or mean diastolic HBP ≥85 mm Hg. Of the 200 participants, 188 (94%) returned their home blood pressure monitors with valid data. The median number of HBP recordings was 10 (interquartile range, 7-14). Presurgical CBP thresholds of 140/90, 150/95, and 160/100 mm Hg yielded positive predictive values (95% confidence interval) for elevated HBP of 84.1% (0.78-0.89), 87.5% (0.81-0.92), and 94.6% (0.87-0.99), respectively. In contrast, self-reported BP control, antihypertensive treatment, availability of primary care, and preoperative pain scores demonstrated poor agreement with elevated HBP. Elevated preoperative CBP is highly predictive of longitudinally elevated HBP. BP measurement during presurgical assessment may provide a way to improve longitudinal detection and treatment of hypertension. Copyright © 2018 American Heart Association. Published by Elsevier Inc. All rights reserved.

  3. A glucagon-like peptide-1 receptor agonist reduces intracranial pressure in a rat model of hydrocephalus

    DEFF Research Database (Denmark)

    Botfield, Hannah F; Uldall, Maria S; Westgate, Connar S J

    2017-01-01

    Current therapies for reducing raised intracranial pressure (ICP) under conditions such as idiopathic intracranial hypertension or hydrocephalus have limited efficacy and tolerability. Thus, there is a pressing need to identify alternative drugs. Glucagon-like peptide-1 receptor (GLP-1R) agonists...

  4. Blood pressure modifies retinal susceptibility to intraocular pressure elevation.

    Directory of Open Access Journals (Sweden)

    Zheng He

    Full Text Available Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP. An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion, moderate (∼100 mmHg, saline, or high levels (∼160 mmHg, angiotensin II of mean arterial pressure (MAP, n = 5-10 per group were subjected to IOP challenge (10-120 mmHg, 5 mmHg steps every 3 minutes. Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave and inner retinal function (scotopic threshold response or STR. Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow.

  5. Relationship between intracranial pressure and antifungal agents levels in the CSF of patients with cryptococcal meningitis.

    Science.gov (United States)

    Wirth, Fernanda; de Azevedo, Maria Isabel; Pilla, Carmen; Aquino, Valério Rodrigues; Neto, Gustavo Wissmann; Goldani, Luciano Zubaran

    2018-04-01

    The purpose of this study was to evaluate the influence of intracranial hypertension in the cerebrospinal fluid (CSF) levels of amphotericin B and fluconazole levels of patients with cryptococcal meningitis. CSF samples and intracranial pressure were obtained by means of routine punctures performed at days 1, 7, and 14 of therapy, respectively. Amphotericin B and fluconazole CSF levels were measured by HPLC method as previously described. The minimum inhibitory concentration for amphotericin B, fluconazole, 5΄flucytosine, and voriconazole of each Cryptococcus isolate was performed according to CLSI. The predominant Cryptococcus species found was C. neoformans, and the major underlying condition was AIDS. Only one CSF sample had a detectable level for amphotericin B during the 14 days of therapy. Fluconazole CSF levels progressively increased from day 1 to day 14 of therapy for most cases. Fluconazole levels in the CSF were above the minimum inhibitory concentrations (MICs) for Cryptococcus during the initial 14 days of antifungal therapy. Variations of intracranial pressure did not affect amphotericin B and fluconazole levels in the CSF. The generalized estimating correlation (GEE) and Spearman correlation test (SCT) showed no significant correlation between the amphotericin B or fluconazole concentrations in the CSF and intracranial pressure (P = .953 and P = .093, respectively for GEE test and P = .477 and P = .847, respectively, for SCT). Combination therapy of amphotericin B with fluconazole was effective in 60% of the patients considering CSF cultures were negative in 9 of 15 patients after 14 days of therapy. Further studies are necessary to evaluate the role of intracranial hypertension on the therapeutic efficacy of different antifungal agents in patients with cryptococcal meningitis.

  6. Intraoperative intracranial pressure and cerebral perfusion pressure for predicting surgical outcome in severe traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Tai-Hsin Tsai

    2013-10-01

    Full Text Available Intraoperative intracranial pressure (ICP and cerebral perfusion pressure (CPP were evaluated for use as prognostic indicators after surgery for severe traumatic brain injury (TBI, and threshold ICP and CPP values were determined to provide guidelines for patient management. This retrospective study reviewed data for 66 patients (20 females and 46 males aged 13–83 years (average age, 48 years who had received decompressive craniectomy and hematoma evacuation for severe TBI. The analysis of clinical characteristics included Glascow Coma Scale score, trauma mechanism, trauma severity, cerebral hemorrhage type, hematoma thickness observed on computed tomography scan, Glasgow Outcome Scale score, and mortality. Patients whose treatment included ICP monitoring had significantly better prognosis (p < 0.001 and significantly lower mortality (p = 0.016 compared to those who did not receive ICP monitoring. At all three major steps of the procedure, i.e., creation of the burr hole, evacuation of the hematoma, and closing of the wound, intraoperative ICP and CPP values significantly differed. The ICP and CPP values were also significantly associated with surgical outcome in the severe TBI patients. Between hematoma evacuation and wound closure, ICP and CPP values differed by 6.8 ± 4.5 and 6.5 ± 4.6 mmHg, respectively (mean difference, 6 mmHg. Intraoperative thresholds were 14 mmHg for ICP and 56mmH for CPP. Monitoring ICP and CPP during surgery improves management of severe TBI patients and provides an early prognostic indicator. During surgery for severe TBI, early detection of increased ICP is also crucial for enabling sufficiently early treatment to improve surgical outcome. However, further study is needed to determine the optimal intraoperative ICP and CPP thresholds before their use as subjective guidelines for managing severe TBI patients.

  7. Proteomic Assessment of Fluid Shifts and Association with Visual Impairment and Intracranial Pressure in Twin Astronauts

    Science.gov (United States)

    Rana, Brinda K.; Stenger, Michael B.; Lee, Stuart M. C.; Macias, Brandon R.; Siamwala, Jamila; Piening, Brian Donald; Hook, Vivian; Ebert, Doug; Patel, Hemal; Smith, Scott; hide

    2016-01-01

    BACKGROUND: Astronauts participating in long duration space missions are at an increased risk of physiological disruptions. The development of visual impairment and intracranial pressure (VIIP) syndrome is one of the leading health concerns for crew members on long-duration space missions; microgravity-induced fluid shifts and chronic elevated cabin CO2 may be contributing factors. By studying physiological and molecular changes in one identical twin during his 1-year ISS mission and his ground-based co-twin, this work extends a current NASA-funded investigation to assess space flight induced "Fluid Shifts" in association with the development of VIIP. This twin study uniquely integrates physiological and -omic signatures to further our understanding of the molecular mechanisms underlying space flight-induced VIIP. We are: (i) conducting longitudinal proteomic assessments of plasma to identify fluid regulation-related molecular pathways altered by long-term space flight; and (ii) integrating physiological and proteomic data with genomic data to understand the genomic mechanism by which these proteomic signatures are regulated. PURPOSE: We are exploring proteomic signatures and genomic mechanisms underlying space flight-induced VIIP symptoms with the future goal of developing early biomarkers to detect and monitor the progression of VIIP. This study is first to employ a male monozygous twin pair to systematically determine the impact of fluid distribution in microgravity, integrating a comprehensive set of structural and functional measures with proteomic, metabolomic and genomic data. This project has a broader impact on Earth-based clinical areas, such as traumatic brain injury-induced elevations of intracranial pressure, hydrocephalus, and glaucoma. HYPOTHESIS: We predict that the space-flown twin will experience a space flight-induced alteration in proteins and peptides related to fluid balance, fluid control and brain injury as compared to his pre-flight protein

  8. Effects of hyperbaric treatment in cerebral air embolism on intracranial pressure, brain oxygenation, and brain glucose metabolism in the pig

    NARCIS (Netherlands)

    van Hulst, Robert A.; Drenthen, Judith; Haitsma, Jack J.; Lameris, Thomas W.; Visser, Gerhard H.; Klein, Jan; Lachmann, Burkhard

    2005-01-01

    OBJECTIVE: To evaluate the effects of hyperbaric oxygen treatment after cerebral air embolism on intracranial pressure, brain oxygenation, brain glucose/lactate metabolism, and electroencephalograph. DESIGN: Prospective animal study. SETTING: Hyperbaric chamber. SUBJECTS: Eleven Landrace/Yorkshire

  9. Effects of dexamethasone and cox inhibitors on intracranial pressure and cerebral perfusion in the lipopolysaccharide treated rats with hyperammonemia

    DEFF Research Database (Denmark)

    Rohde, Johan; Pedersen, Hans; Bjerring, Peter N

    2015-01-01

    INTRODUCTION: Systemic inflammation may affect the brain by aggravating the stage of encephalopathy and increasing intracranial pressure (ICP) especially if liver insufficiency with hyperammonemia is present. The aim of this study was to determine if the influence of concomitant hyperammonemia...

  10. Intracranial pressure-induced optic nerve sheath response as a predictive biomarker for optic disc edema in astronauts

    NARCIS (Netherlands)

    Wostyn, Peter; De Deyn, Peter Paul

    2017-01-01

    A significant proportion of the astronauts who spend extended periods in microgravity develop ophthalmic abnormalities. Understanding this syndrome, called visual impairment and intracranial pressure (VIIP), has become a high priority for National Aeronautics and Space Administration, especially in

  11. Mannitol-induced rebleeding from intracranial aneurysm. Case report

    DEFF Research Database (Denmark)

    Rosenørn, J; Westergaard, L; Hansen, P H

    1983-01-01

    A case is presented in which rebleeding from an intracranial saccular aneurysm occurred a few minutes after intravenous administration of mannitol during surgery. The relationship between the reducing effect of mannitol on elevated intracranial pressure and the increased pressure gradient across...

  12. Mannitol-induced rebleeding from intracranial aneurysm. Case report

    DEFF Research Database (Denmark)

    Rosenørn, J; Westergaard, L; Hansen, P H

    1983-01-01

    A case is presented in which rebleeding from an intracranial saccular aneurysm occurred a few minutes after intravenous administration of mannitol during surgery. The relationship between the reducing effect of mannitol on elevated intracranial pressure and the increased pressure gradient across ...

  13. Risk for intracranial pressure increase related to enclosed air in post-craniotomy patients during air ambulance transport: a retrospective cohort study with simulation.

    Science.gov (United States)

    Brändström, Helge; Sundelin, Anna; Hoseason, Daniela; Sundström, Nina; Birgander, Richard; Johansson, Göran; Winsö, Ola; Koskinen, Lars-Owe; Haney, Michael

    2017-05-12

    Post-craniotomy intracranial air can be present in patients scheduled for air ambulance transport to their home hospital. We aimed to assess risk for in-flight intracranial pressure (ICP) increases related to observed intracranial air volumes, hypothetical sea level pre-transport ICP, and different potential flight levels and cabin pressures. A cohort of consecutive subdural hematoma evacuation patients from one University Medical Centre was assessed with post-operative intracranial air volume measurements by computed tomography. Intracranial pressure changes related to estimated intracranial air volume effects of changing atmospheric pressure (simulating flight and cabin pressure changes up to 8000 ft) were simulated using an established model for intracranial pressure and volume relations. Approximately one third of the cohort had post-operative intracranial air. Of these, approximately one third had intracranial air volumes less than 11 ml. The simulation estimated that the expected changes in intracranial pressure during 'flight' would not result in intracranial hypertension. For intracranial air volumes above 11 ml, the simulation suggested that it was possible that intracranial hypertension could develop 'inflight' related to cabin pressure drop. Depending on the pre-flight intracranial pressure and air volume, this could occur quite early during the assent phase in the flight profile. DISCUSSION: These findings support the idea that there should be radiographic verification of the presence or absence of intracranial air after craniotomy for patients planned for long distance air transport. Very small amounts of air are clinically inconsequential. Otherwise, air transport with maintained ground-level cabin pressure should be a priority for these patients.

  14. Bernoulli's Principle Applied to Brain Fluids: Intracranial Pressure Does Not Drive Cerebral Perfusion or CSF Flow.

    Science.gov (United States)

    Schmidt, Eric; Ros, Maxime; Moyse, Emmanuel; Lorthois, Sylvie; Swider, Pascal

    2016-01-01

    In line with the first law of thermodynamics, Bernoulli's principle states that the total energy in a fluid is the same at all points. We applied Bernoulli's principle to understand the relationship between intracranial pressure (ICP) and intracranial fluids. We analyzed simple fluid physics along a tube to describe the interplay between pressure and velocity. Bernoulli's equation demonstrates that a fluid does not flow along a gradient of pressure or velocity; a fluid flows along a gradient of energy from a high-energy region to a low-energy region. A fluid can even flow against a pressure gradient or a velocity gradient. Pressure and velocity represent part of the total energy. Cerebral blood perfusion is not driven by pressure but by energy: the blood flows from high-energy to lower-energy regions. Hydrocephalus is related to increased cerebrospinal fluid (CSF) resistance (i.e., energy transfer) at various points. Identification of the energy transfer within the CSF circuit is important in understanding and treating CSF-related disorders. Bernoulli's principle is not an abstract concept far from clinical practice. We should be aware that pressure is easy to measure, but it does not induce resumption of fluid flow. Even at the bedside, energy is the key to understanding ICP and fluid dynamics.

  15. Noninvasive Intracranial Pressure and Tissue Oxygen Measurements for Space and Earth

    Science.gov (United States)

    Hargens, A. R.; Ballard, R. E.; Murthy, G.; Watenpaugh, D. E.

    1994-01-01

    The paper discusses the following: Increasing intracranial pressure in humans during simulated microgravity. and near-infrared monitoring of model chronic compartment syndrome in exercising skeletal muscle. Compared to upright-seated posture, 0 deg. supine, 6 deg. HDT, and 15 deg. HDT produced TMD changes of 317 +/- 112, 403 +/- 114, and 474 +/- 112 n1 (means +/- S.E.), respectively. Furthermore, postural transitions from 0 deg. supine to 6 deg. HDT and from 6 deg. to 15 deg. HDT generated significant TMD changes (p less than 0.05). There was no hysteresis when postural transitions to HDT were compared to reciprocal transitions toward upright seated posture. Currently, diagnosis of chronic compartment syndrome (CCS) depends on measurement of intramuscular pressure by invasive catheterization. We hypothesized that this syndrome can be detected noninvasively by near-infrared (NIR) spectroscopy, which tracks variations in muscle hemoglobin/myoglobin oxygen saturation. CCS was simulated in the tibialis anterior muscle of 7 male and 3 female subjects by gradual inflation of a cuff placed around the leg to 40 mmHg during 14 minutes of cyclic isokinetic dorsiflexion exercise. On a separate day, subjects underwent the identical exercise protocol with no external compression. In both cases, tissue oxygenation (T(sub O2) was measured in the tibialis anterior by NIR spectroscopy and normalized to a percentage scale between baseline and a T(sub O2) nadir reached during exercise to ischemic exhaustion. Over the course of exercise, T(sub O2) declined at a rate of 1.4 +/- 0.3% per minute with model CCS, yet did not decrease during control exercise. Post-exercise recovery of T(sub O2) was slower with model CCS (2.5 +/- 0.6 min) than in control (1.3 +/- 0.2 min). These results demonstrate that NIR spectroscopy can detect muscle deoxygenation caused by pathologically elevated intramuscular pressure in exercising skeletal muscle. Consequently, this technique shows promise as a

  16. Abnormalities of Microcirculation and Intracranial and Cerebral Perfusion Pressures in Severe Brain Injury

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2008-01-01

    Full Text Available Objective: to evaluate the states of microcirculation, cerebral perfusion intracranial pressures in patients with isolated severe brain injury (SBI and to determine their possible relationships. Subjects and methods. 148 studies were performed in 16 victims with SBI. According to the outcome of brain traumatic disease, the patients were divided into two groups: 1 those who had a good outcome (n=8 and 2 those who had a fatal outcome (n=8. Microcirculation was examined by skin laser Doppler flowmetry using a LAKK-01 capillary blood flow laser analyzer (LAZMA Research-and-Production Association, Russian Federation. All the victims underwent surgical interventions to remove epi-, subdural, and intracerebral hematomas. A Codman subdural/intraparenchymatous intracranial pressure (ICD sensor (Johnson & Johnson, United Kingdom was intraoperatively inserted in the victims. Cerebral perfusion pressure (CPP was calculated using the generally accepted formula: CPP = MBP (mean blood pressure — ICD. ICD, CPP, and microcirculation were studied on postoperative days 1, 3, 5, and 7. Their values were recorded simultaneously. Ninety and 58 studies were conducted in the group of patients with good and fatal outcomes, respectively. Results. No correlation between the changes in MBP, ICD, and microcirculatory parameters suggested that the value of ICD was determined by the nature of brain damage and it was the leading and determining indicator in the diagnosis and treatment of secondary cerebral lesions. The amplitude of low-frequency fluctuations directly correlated with ICD, which indicated that they might be used to evaluate cerebral perfusion and impaired cerebral circulation indirectly in victims with severe brain injury. Conclusion. The laser Doppler flowmetric technique makes it possible not only to qualitatively, but also quantitatively determine changes in the tissue blood flow system in severe brain injury. With this technique, both the local and central

  17. Occipital Intraosseous Hemangioma over Torcula: Unusual Presentation with Raised Intracranial Pressure.

    Science.gov (United States)

    Rao, K V L N; Beniwal, Manish; Vazhayil, Vikas; Somanna, Sampath; Yasha, T C

    2017-12-01

    Hemangiomas of the bone are benign, uncommon, slow-growing lesions accounting for occipital hemangiomas are rare, and occipital hemangiomas presenting with features of raised intracranial tension are, with only 2 cases reported to date. In this case report, we describe the unique case of a 30-year-old male patient presenting with raised intracranial pressure due to venous obstruction at the torcula. The patient underwent excision of the lesion and became symptom free. Although these are benign lesions, they can have a varied clinical presentation. An understanding of the different clinical presentations and surgical nuances in excising such tumors can lead to early diagnosis and good patient outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Time Course of Changes in Extravascular Lung Water Index, Intracranial and Cerebral Perfusion Pressures in Acute Cerebral Circulatory Disorders

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2009-01-01

    Full Text Available Objective: to study the time course of changes in extravascular lung water index (ELWI and intracranial and cerebral perfusion pressures (ICP and CPP and to determine their possible relationships in acute cerebral circulatory disorders (ACCD. Subject and methods. ELWI, pulmonary vascular permeability index (PVPI, ICP, CPP, and central hemodynamics were studied by transpulmonary thermodilution and current X-ray studies were conducted in 18 patients on days 1, 3, 5, and 7 of ACCD. Results. Examinations revealed a supratentorial dislocation of the brain in 6 persons; its subtento-rial dislocation was found in 1 case; supra- and subtentorial dislocations were seen in 6. In patients, ELWI and PVPI increased from days 1 and 5, respectively. The high baseline ICP increased over time. CPP remained unchanged. Preserved left ventricular contractility, enhanced myocardial one, a significant direct correlation between ELWI and PVPI, as well as their increase confirmed that the noncardiogenic genesis was responsible for increased ELWI. A direct significant correlation was found between ICP and ELWI, ICP and PVPI. Against this background, acute respiratory distress syndrome developed in 14 patients with pneumonia evolving in its presence in 7 patients. Conclusion. In ACCD, ELWI increases in the first 24 hours of the acute period. One of its causes is, along with others, primary and/or secondary damage to the brainstem structures with elevated ICP and progressive brain dislocation. The determination of ICP, unlike CPP, is crucial in the diagnosis and treatment of primary/secondary brain injuries and in prognosis. Key words: acute cerebral circulatory disorder, extravascular lung fluid, pulmonary vascular permeability, intracranial pressure, cerebral perfusion pressure, acute respiratory distress syndrome.

  19. A Quad-Cantilevered Plate micro-sensor for intracranial pressure measurement.

    Science.gov (United States)

    Lalkov, Vasko; Qasaimeh, Mohammad A

    2017-07-01

    This paper proposes a new design for pressure-sensing micro-plate platform to bring higher sensitivity to a pressure sensor based on piezoresistive MEMS sensing mechanism. The proposed design is composed of a suspended plate having four stepped cantilever beams connected to its corners, and thus defined as Quad-Cantilevered Plate (QCP). Finite element analysis was performed to determine the optimal design for sensitivity and structural stability under a range of applied forces. Furthermore, a piezoresistive analysis was performed to calculate sensor sensitivity. Both the maximum stress and the change in resistance of the piezoresistor associated with the QCP were found to be higher compared to previously published designs, and linearly related to the applied pressure as desired. Therefore, the QCP demonstrates greater sensitivity, and could be potentially used as an efficient pressure sensor for intracranial pressure measurement.

  20. Postural influence on intracranial and cerebral perfusion pressure in ambulatory neurosurgical patients

    DEFF Research Database (Denmark)

    Petersen, Lonnie Grove; Petersen, Johan Casper Grove; Andresen, Morten

    2016-01-01

    .4±4.2 mmHg when standing up (Phydrostatic pressure gradient with reference just below the heart, likely reflecting the venous hydrostatic...... indifference point. When upright, the decrease in ICP was attenuated, corresponding to formation of a separate hydrostatic gradient with reference to the base of the skull, likely reflecting the site of venous collapse. ICP therefore seems to be governed by pressure in the draining veins and collapse of neck......We evaluated postural effects on intracranial pressure (ICP) and cerebral perfusion pressure (CPP: mean arterial pressure (MAP) - ICP) in neurosurgical patients undergoing 24-hour ICP monitoring as part of their diagnostic workup. We identified 9 patients (5 women, age 44±20 yrs.; mean±SD) who were...

  1. The hidden magnitude of raised blood pressure and elevated blood ...

    African Journals Online (AJOL)

    Conclusions: The prevalence of undiagnosed raised blood pressure and elevated blood sugar was high in Ethiopia and only very small percentage of people had been aware of their high blood pressure and elevated blood sugar. Policy makers in the health sector including other health development partners need to ...

  2. [Special artificial respiration procedures and intracranial pressure. Animal experiment studies, development and use of a new pressure measuring technic, clinical aspects].

    Science.gov (United States)

    Schedl, R

    1985-01-01

    We investigated the influence of Forced Diffusion Ventilation (FDV), a special form of High Frequency Ventilation (HFV), on elevated intracranial pressure (ICP) in 5 dogs. Elevation of ICP was standardized by inflation of an epidural balloon. A typical finding with FDV is a reduced intrapleural pressure and therefore one could expect a better cerebrovenous drainage influencing ICP. Nevertheless, we found no changes in mean ICP under conditions of FDV compared with IPPV. Respirator-synchronous fluctuations of ICP, cisternal cerebrospinal fluid pressure and intrapleural pressure were drastically reduced with FDV. This phenomenon has been already reported by other groups as a typical effect of HFV with rates of 100/min. One can speculate, that this immediate impact of HFV on ICP-curves might be of some advantage in patients with critically reduced intracranial compliance requiring long-term artificial ventilation, because peaks and amplitudes of ICP are reduced. Our clinical experience with High Frequency Pulsation (HFP) includes 11 patients with severe brain trauma. In clinical routine this method of HFV is more facile to applicate than FDV, because there is no need of a special endotracheal tube and sufficient CO2-elimination is not strongly dependent on precise position of the tube. But HFP, as FDV, includes all advantages of respiratory systems, that are open against atmosphere (coughing and simultaneous breathing, without drastically increasing airway pressure, suction during respiration, etc.). However, we could find no special advantages or disadvantages in ICP-course during long-term application of HFP (up to 10 days). Because application of HFV is dependent on special technical equipment, we investigated in 6 patients the influence of respiratory frequency, tidal volume and inspiratory flow on ICP-fluctuations using conventional ventilators. ICP was recorded by a new, self constructed pneumatic epidural pressure sensor. Ventilator-related ICP

  3. Electrostatic discharges and their effect on the validity of registered values in intracranial pressure monitors

    DEFF Research Database (Denmark)

    Andresen, Morten; Thomsen, Ole Cornelius; Juhler, Marianne

    2013-01-01

    Object Intracranial pressure (ICP) monitoring is used extensively in clinical practice, and as such, the accuracy of registered ICP values is paramount. Clinical observations of nonphysiological changes in ICP have called into question the accuracy of registered ICP values. Subsequently, the auth......Object Intracranial pressure (ICP) monitoring is used extensively in clinical practice, and as such, the accuracy of registered ICP values is paramount. Clinical observations of nonphysiological changes in ICP have called into question the accuracy of registered ICP values. Subsequently......, the authors have tried to determine if the ICP monitors from major manufacturers were affected by electrostatic discharges (ESDs), if the changes were permanent or transient in nature, and if the changes were modified by the addition of different electrical appliances normally used in the neurointensive care....... Results Five pressure monitors from 4 manufacturers were evaluated. Three monitors containing electrical circuitry at the tip of the transducer were all affected by ESDs. Clinically significant permanent changes in the reported ICP values for 1 pressure monitor were observed, as well as temporary...

  4. Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury

    Directory of Open Access Journals (Sweden)

    Anton Lund

    2017-01-01

    Full Text Available Dialysis disequilibrium syndrome (DDS is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered.

  5. Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury.

    Science.gov (United States)

    Lund, Anton; Damholt, Mette B; Strange, Ditte G; Kelsen, Jesper; Møller-Sørensen, Hasse; Møller, Kirsten

    2017-01-01

    Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT) revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP) monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT) was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered.

  6. Assessment of the usability of a digital learning technology prototype for monitoring intracranial pressure

    Directory of Open Access Journals (Sweden)

    Lilian Regina de Carvalho

    Full Text Available ABSTRACT Objective: to assess the usability of a digital learning technology prototype as a new method for minimally invasive monitoring of intracranial pressure. Method: descriptive study using a quantitative approach on assessing the usability of a prototype based on Nielsen's ten heuristics. Four experts in the area of Human-Computer interaction participated in the study. Results: the evaluation delivered eight violated heuristics and 31 usability problems in the 32 screens of the prototype. Conclusion: the suggestions of the evaluators were critical for developing an intuitive, user-friendly interface and will be included in the final version of the digital learning technology.

  7. Isoflurane rescue therapy for bronchospasm reduces intracranial pressure in a patient with traumatic brain injury.

    Science.gov (United States)

    Gradisek, Primoz; Dolenc, Simon

    2016-01-01

    To assess the unusual use of a volatile anaesthetic for treatment of life-threatening bronchospasm in a patient with traumatic brain injury (TBI). Case report. This study presents a previously healthy 30-year-old man with severe TBI and bronchospasm-induced acute hypercapnia. He was treated with inhaled isoflurane in combination with monitoring of intracranial pressure (ICP) and regional cerebral blood flow (rCBF). Three-day-long isoflurane treatment resolved drug-refractory bronchospasm, decreased airway pressure and improved gas exchange, even at a low end-tidal concentration (0.3-0.5 vol%). Although rCBF was increased by 18 ml min(-1) 100 g(-1) during isoflurane treatment, there was a significant decrease in ICP (21 (SD = 3) mmHg, 9 (SD = 5) mmHg, 2 (SD = 3) mmHg; during pre-treatment, treatment and post-treatment, respectively; p < 0.001). Improved autoregulation due to lower partial pressure of carbon dioxide, restoration of carbon dioxide reactivity, isoflurane-induced regional differences in rCBF and improved microcirculation may have been responsible for the prompt and long-lasting normalization of ICP. The patient had no TBI-related disability at 6 months post-injury. Isoflurane at a low dose can be an effective and safe treatment option for drug-refractory bronchospasm in a patient with traumatic intracranial hypertension, provided that multimodality neuromonitoring is used.

  8. EFFECTS OF L-LYSINE AESCINAT ON INTRACRANIAL PRESSURE IN CRITICALLY ILL PATIENTS WITH SEVERE TRAUMATIC BRAIN INJURY

    Directory of Open Access Journals (Sweden)

    S. S. Petrikov

    2016-01-01

    Full Text Available Abstract. Increased intracranial pressure results in cerebral blood flow decrease and cerebral edema formation. Correction of intracranial hypertension is one of the most important goals of intensive care in patients with severe traumatic brain injury. Objectives To determine the effects of L-lysine aescinat on ICP in patients with severe TBI.Material and methods. Twenty patients with TBI and Glasgow coma scale below 9 enrolled in the study. All patients were operated: 6 patients underwent craniotomy and intracranial hematoma removing; 11 — decompressive craniotomy and intracranial hematoma removing. In 3 patients only ICP-sensor was implanted. ICP-monitoring was used in all patients. Ten patients were randomized to L-lysine aescinat treatment (daily dose of 20 ml for 7 days after surgery (study group, 10 — to standard therapy (control group. We perfomed a comparative analysis of the mean ICP and the incidence of ICH within 7 days after surgery in the study and control groups.Results. The length of ICP monitoring was 6.4±3.7 days: in the control group — 7.6±4.9 days, in the study group — 5.2±1.4 days. Mean intracranial pressure was less in the study group as compared to patients in the control group. The number of intracranial hypertension episodes was higher in the control group compared with patients who received L-lysine aescinat.Conclusion. L-lysine aescinat treatment in patients with severe traumatic brain injury is accompanied by reduction of mean intracranial pressure and the number of intracranial hypertension episodes.

  9. Frank-ter Haar syndrome associated with sagittal craniosynostosis and raised intracranial pressure.

    Science.gov (United States)

    Bendon, Charlotte L; Fenwick, Aimée L; Hurst, Jane A; Nürnberg, Gudrun; Nürnberg, Peter; Wall, Steven A; Wilkie, Andrew O M; Johnson, David

    2012-11-09

    Frank-ter Haar syndrome is a rare disorder associated with skeletal, cardiac, ocular and craniofacial features including hypertelorism and brachycephaly. The most common underlying genetic defect in Frank-ter Haar syndrome appears to be a mutation in the SH3PXD2B gene on chromosome 5q35.1. Craniosynostosis, or premature fusion of the calvarial sutures, has not previously been described in Frank-ter Haar syndrome. We present a family of three affected siblings born to consanguineous parents with clinical features in keeping with a diagnosis of Frank-ter Haar syndrome. All three siblings have a novel mutation caused by the deletion of exon 13 of the SH3PXD2B gene. Two of the three siblings also have non-scaphocephalic sagittal synostosis associated with raised intracranial pressure. The clinical features of craniosynostosis and raised intracranial pressure in this family with a confirmed diagnosis of Frank-ter Haar syndrome expand the clinical spectrum of the disease. The abnormal cranial proportions in a mouse model of the disease suggests that the association is not coincidental. The possibility of craniosynostosis should be considered in individuals with a suspected diagnosis of Frank-ter Haar syndrome.

  10. Microbiological methane production at elevated pressure

    International Nuclear Information System (INIS)

    Friedmann, H.; Maerkl, H.

    1994-01-01

    Taking the fermentation of waste water from the production of baker's yest as an example, experimental and theoretical examinations of a qualitative and quantitative listing of the effects of pressure on the microbiological methane production are presented. As the waste water used for the experiments was very rich in sulphates, the influence of the hydrogen sulphide constituted from those played a particularly important role. Experiments showed that the essential influence of pressure is constituted by the increased solubility of the produced gases. The increased quantities of dissolved carbon dioxide in particular result in a lowering of the pH-value with increasing pressure. The gas composition changes at the same time. The higher the pressure the higher also the portion of methane contained in the biogas but the lower the portions of carbon dioxide and hydrogen sulphide. Experimental findings could be represented comparatively well by a mathematical model. This points at the fact that the physical and chemical working mechanisms were grasped correctly by the model. The mathematical description helped much to increase the understanding of the physical and chemical working mechanisms in biogas reactors. This understanding makes it possible for the developer as well as for the operator of biogas installations to control the process by constructive measures and mearuses concerning operation technology. (orig.) [de

  11. Comparison of the sagittal sinus cross-sectional area between patients with multiple sclerosis, hydrocephalus, intracranial hypertension and spontaneous intracranial hypotension: a surrogate marker of venous transmural pressure?

    Science.gov (United States)

    Bateman, Grant A; Lechner-Scott, Jeannette; Copping, Ross; Moeskops, Christopher; Yap, Swee Leong

    2017-07-06

    There is evidence that patients with multiple sclerosis (MS) and hydrocephalus share some common pathophysiological mechanisms. Alterations in CSF pressure are known to affect cerebral venous sinus geometry. To further explore these mechanisms, we measured the superior sagittal sinus (SSS) cross-sectional area 3 cm above the torcular using T2 images in 20 MS, 10 spontaneous intracranial hypotension (SIH), 21 hydrocephalus and 20 idiopathic intracranial hypertension (IIH) patients and compared with 20 matched controls. The SSS area was reduced by 25% in hydrocephalus (p = 0.0008), increased by 22% (p = 0.037) in SIH and unchanged in IIH compared to matched controls. In MS there was a 16% increase in SSS area (p = 0.01).The findings suggest that changes in SSS cross-sectional are common between MS and SIH patients, while in hydrocephalus and IIH these are different.

  12. Haemodynamic patterns in ST-elevation myocardial infarction : incidence and correlates of elevated filling pressures

    NARCIS (Netherlands)

    Bergstra, A.; Svilaas, T.; van Veldhuisen, D. J.; van den Heuvel, A. F. M.; van der Horst, I. C. C.; Zijlstra, F.

    Objectives. We sought to study the incidence and clinical correlates of elevated filling pressures in ST-elevation myocardial infarction (STEMI) patients, without physical signs of heart failure and treated with primary coronary angioplasty. Background. Haemodynamic data, as measured with a

  13. A preliminary study for investigating idiopatic normal pressure hydrocephalus by means of statistical parameters classification of intracranial pressure recordings.

    Science.gov (United States)

    Calisto, A; Bramanti, A; Galeano, M; Angileri, F; Campobello, G; Serrano, S; Azzerboni, B

    2009-01-01

    The objective of this study is to investigate Id-iopatic Normal Pressure Hydrocephalus (INPH) through a multidimensional and multiparameter analysis of statistical data obtained from accurate analysis of Intracranial Pressure (ICP) recordings. Such a study could permit to detect new factors, correlated with therapeutic response, which are able to validate a predicting significance for infusion test. The algorithm developed by the authors computes 13 ICP parameter trends on each of the recording, afterward 9 statistical information from each trend is determined. All data are transferred to the datamining software WEKA. According to the exploited feature-selection techniques, the WEKA has revealed that the most significant statistical parameter is the maximum of Single-Wave-Amplitude: setting a 27 mmHg threshold leads to over 90% of correct classification.

  14. An investigation into the regulation of intra-cranial pressure and its influence upon the surrounding cranial bones.

    Science.gov (United States)

    Gard, Graham

    2009-07-01

    The aim of this study is to present a rational coherent hypothesis to explain the palpable involuntary movements of the cranium. The arterial and venous anatomy inside and around the skull and spinal column presents a complete vascular system with the capacity to regulate intra-cranial pressure to a level of equilibrium slightly higher than atmospheric pressure. Variations in cerebrospinal fluid (csf) pressure control the volume of blood draining through the cavernous sinus and hence into the inter-vertebral venous plexus in relation to the jugular vein. Stable intra-cranial pressure is maintained by a controlled release of venous blood through the inter-vertebral venous plexus (slow) and the jugular vein (fast) in the cavernous sinus. Any distortion of the skull from its healthy state will lead to reduced intra-cranial volume. The process of release from the state of compression has been interpreted as "cranial rhythm" but may be a mechanical adjustment increasing the internal volume of the skull, aided by the continual maintenance of stable intracranial pressure. This involuntary movement is capable of being assisted manually.

  15. Understanding idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Markey, Keira A; Mollan, Susan P; Jensen, Rigmor H

    2016-01-01

    Idiopathic intracranial hypertension is a disorder characterised by raised intracranial pressure that predominantly affects young, obese women. Pathogenesis has not been fully elucidated, but several causal factors have been proposed. Symptoms can include headaches, visual loss, pulsatile tinnitus...

  16. Blood Pressure and Intracranial Aneurysms in Autosomal Dominant Polycystic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Mariusz Niemczyk

    2014-12-01

    Full Text Available Background/Aims: Autosomal dominant polycystic kidney disease (ADPKD is correlated with an increased frequency of both intracranial aneurysms (ICANs, and arterial hypertension (AH. The aim of our study was to search for the association between blood pressure (BP and ICANs in ADPKD patients. Methods: Sixty-eight adult, pre-dialysis phase ADPKD patients underwent both screening for ICANs with magnetic resonance angiography of the brain, and ambulatory blood pressure monitoring (ABPM. Results: ICANs were diagnosed in 10 patients (ICAN(+ group, while in 58 were not (ICAN(- group. The nighttime maximum diastolic blood pressure (DBP, maximum increase in DBP from measurement to measurement (positive delta of DBP at night, and the standard deviation of the daytime mean arterial pressure were significantly higher in ICAN(+ compared to ICAN(- patients. Additionally, in a subgroup of patients after 45 years-of-age, ICAN(+ patients had significantly higher maximum 24-hour and daytime systolic blood pressure, maximum 24-hour, daytime, nighttime DBP, maximum daytime and nighttime positive delta of DBP compared to ICAN(- cases. Conclusions: Development of ICANs in hypertensive ADPKD patients is accompanied with higher values of some BP parameters measured by ABPM. Hypertensive ADPKD patients with substantial fluctuations in BP assessed by ABPM, especially those after 45 years-of-age, should become candidates for screening for ICANs.

  17. Fluid Shifts Before, During and After Prolonged Space Flight and Their Association with Intracranial Pressure and Visual Impairment

    Science.gov (United States)

    Stenger, Michael; Hargens, Alan; Dulchavsky, Scott

    2014-01-01

    Future human space travel will primarily consist of long duration missions onboard the International Space Station or exploration class missions to Mars, its moons, or nearby asteroids. Current evidence suggests that long duration missions might increase risk of permanent ocular structural and functional changes, possibly due to increased intracranial pressure resulting from a spaceflight-induced cephalad (headward) fluid shift.

  18. Automated intracranial pressure-controlled cerebrospinal fluid external drainage with LiquoGuard.

    Science.gov (United States)

    Linsler, Stefan; Schmidtke, Mareike; Steudel, Wolf Ingo; Kiefer, Michael; Oertel, Joachim

    2013-08-01

    LiquoGuard is a new device for intracranial pressure (ICP)-controlled drainage of cerebrospinal fluid (CSF). This present study evaluates the accuracy of ICP measurement via the LiquoGuard device in comparison with Spiegelberg. Thus, we compared data ascertained from simultaneous measurement of ICP using tip-transducer and tip-sensor devices. A total of 1,764 monitoring hours in 15 patients (range, 52-219 h) were analysed. All patients received an intraventricular Spiegelberg III probe with the drainage catheter connected to the LiquoGuard system. ICP reading of both devices was performed on an hourly basis. Statistical analysis was done by applying Pearson correlation and Wilcoxon-matched pair test (p drainage. However, LiquoGuard tends to provide misleading results in slit ventricles. Thus, before these drawbacks are further analysed, the authors recommend additional ICP measurement with internal tip-sensor devices to avoid dangerous erroneous interpretation of ICP data.

  19. Research on simulation and experiment of noninvasive intracranial pressure monitoring based on acoustoelasticity effects

    Directory of Open Access Journals (Sweden)

    Wu J

    2013-08-01

    Full Text Available Jun Wu1, Wei He2, Wei-min Chen1, Lian Zhu21Key Laboratory of Optoelectronic Technology and Systems, 2State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, People’s Republic of ChinaAbstract: The real-time monitoring of intracranial pressure (ICP is very important for craniocerebrally critically ill patients, but it is very difficult to realize long-time monitoring for the traditional invasive method, which very easily infects patients. Many noninvasive methods have emerged, but these have not been able to monitor ICP for long periods in real time, and they are not ready for clinical application. In order to realize long-time, online, real-time, noninvasive monitoring for ICP, a new method based on acoustoelasticity of ultrasound is herein proposed. Experimental models were devised to research the new method for experiment and simulation. Polymethyl methacrylate and hydrogel were adopted for the experiment, and their mechanical properties were very close to the real brain. A numerical solution for acoustoelasticity theory was acquired by simulating calculation based on a finite-element method. This was compared to the experimental value. The results showed a consistent match between theoretical solution and experimental value, with maximum error at most 5%. Thus, the effectiveness of the new method was verified. Theoretical and practical foundation is provided for this new method, and it could be used for animal experimentation or clinical testing in further research.Keywords: medical instruments, noninvasive, intracranial pressure, ultrasonic, acoustoelasticity, biomechanics

  20. Feasibility of Telemetric Intracranial Pressure Monitoring in the Neuro Intensive Care Unit.

    Science.gov (United States)

    Lilja-Cyron, Alexander; Kelsen, Jesper; Andresen, Morten; Fugleholm, Kåre; Juhler, Marianne

    2018-05-03

    Intracranial pressure (ICP) monitoring is crucial in the management of acute neurosurgical conditions such as traumatic brain injury (TBI). However, pathological ICP may persist beyond the admission to the neuro intensive care unit (NICU). We investigated the feasibility of telemetric ICP monitoring in the NICU, as this technology provides the possibility of long-term ICP assessment beyond NICU discharge. In this prospective investigation, we implanted telemetric ICP sensors (Raumedic Neurovent-P-tel) instead of conventional, cabled ICP sensors in patients undergoing decompressive craniectomy. We recorded ICP curves, duration of ICP monitoring, signal quality, and complications. Seventeen patients were included (median age 55 years) and diagnoses were: severe TBI (8), malignant middle cerebral artery infarction (8), and spontaneous intracerebral hemorrhage (1). In total, 3015 h of ICP monitoring were performed, and the median duration of ICP monitoring was 188 h (interquartile range [IQR] 54-259). The ICP signal was lost 613 times (displacement of the reader unit on the skin) for a median of 1.5 min, corresponding to 0.8% of the total monitoring period. When the signal was lost, it could always be restored by realignment of the reader unit on the skin above the telemetric sensor. Sixteen of 17 patients survived the NICU admission, and ICP gradually decreased from 10.7 mm Hg (IQR 7.5-13.6) during the first postoperative day to 6.3 mm Hg (IQR 4.0-8.3) after 1 week in the NICU. All 17 implanted telemetric sensors functioned throughout the NICU admission, and no wound infections were observed. Therefore, telemetric ICP monitoring in an acute neurosurgical setting is feasible. Signal quality and stability are sufficient for clinical decision making based on mean ICP. The low sampling frequency (5 Hz) does not permit analysis of intracranial pulse wave morphology, but resolution is sufficient for calculation of derived indices such as the pressure reactivity

  1. Th1, Th17, CXCL16 and homocysteine elevated after intracranial and cervical stent implantation.

    Science.gov (United States)

    Tang, Yanyan; Wei, Yunfei; Ye, Ziming; Qin, Chao

    2017-08-01

    The presence of Th1 and Th17 cells has been observed as major inducers in inflammation and immune responses associated stenting. However, there is rare data on the impact of Th1, Th17, CXCL16 and homocysteine after cerebral stent implantation. Here, we performed the statistical analysis to first evaluate the variation of the Th17and Th1 cells and their related cytokines, CXCL16 and homocysteine in the peripheral blood of patients with cerebral stenting. The flow cytometry was used to detect the proportion of Th1 and Th17 cells in peripheral blood mononuclear cells (PBMCs). The enzyme-linked immunosorbent assay was used to measure the serum concentrations of IFN-γ, IL-17 and CXCL16. Plasma homocysteine was examined by immunoturbidimetry. The level of Th1, CXCL16 and homocysteine showed an increase at 3 d, followed by the continuous decrease at 7 d and 3 months. The frequency of Th17 cells increased to a peak at three days, and subsequently decreased with a higher level than baseline. Our data revealed that the variation in Th1, Th17, CXCL16 and homocysteine in peripheral blood of patients with stenting may be implicated in inflammation after intracranial and cervical stent implantation. A better understanding of these factors will provide help for further drug design and clinical therapy.

  2. Investigations of Sooting Laminar Coflow Diffusion Flames at Elevated Pressures

    KAUST Repository

    Steinmetz, Scott A.

    2016-12-01

    Soot is a common byproduct of hydrocarbon based combustion systems. It poses a risk to human and environmental health, and can negatively or positively affect combustor performance. As a result, there is significant interest in understanding soot formation in order to better control it. More recently, the need to study soot formation in engine relevant conditions has become apparent. One engine relevant parameter that has had little focus is the ambient pressure. This body of work focuses on the formation of soot in elevated pressure environments, and a number of investigations are carried out with this purpose. Laminar coflow diffusion flames are used as steady, simple soot producers. First, a commonly studied flame configuration is further characterized. Coflow flames are frequently used for fundamental flame studies, particularly at elevated pressures. However, they are more susceptible to buoyancy induced instabilities at elevated pressures. The velocity of the coflow is known to have an effect on flame stability and soot formation, though these have not been characterized at elevated pressures. A series of flames are investigated covering a range of flowrates, pressures, and nozzle diameters. The stability limits of coflow flames in this range is investigated. Additionally, an alternative strategy for scaling these flames to elevated pressures is proposed. Finally, the effect of coflow rate on soot formation is evaluated. Identification of fundamental flames for coordinated research can facilitate our understanding of soot formation. The next study of this work focuses on adding soot concentration and particle size information to an existing fundamental flame dataset for the purpose of numerical model validation. Soot volume fraction and average particle diameters are successfully measured in nitrogen-diluted ethylene-air laminar coflow flames at pressures of 4, 8, 12, and 16 atm. An increase in particle size with pressure is found up to 12 atm, where particle

  3. Patterns of care and persistence after incident elevated blood pressure.

    Science.gov (United States)

    Daley, Matthew F; Sinaiko, Alan R; Reifler, Liza M; Tavel, Heather M; Glanz, Jason M; Margolis, Karen L; Parker, Emily; Trower, Nicole K; Chandra, Malini; Sherwood, Nancy E; Adams, Kenneth; Kharbanda, Elyse O; Greenspan, Louise C; Lo, Joan C; O'Connor, Patrick J; Magid, David J

    2013-08-01

    Screening for hypertension in children occurs during routine care. When blood pressure (BP) is elevated in the hypertensive range, a repeat measurement within 1 to 2 weeks is recommended. The objective was to assess patterns of care after an incident elevated BP, including timing of repeat BP measurement and likelihood of persistently elevated BP. This retrospective study was conducted in 3 health care organizations. All children aged 3 through 17 years with an incident elevated BP at an outpatient visit during 2007 through 2010 were identified. Within this group, we assessed the proportion who had a repeat BP measured within 1 month of their incident elevated BP and the proportion who subsequently met the definition of hypertension. Multivariate analyses were used to identify factors associated with follow-up BP within 1 month of initial elevated BP. Among 72,625 children and adolescents in the population, 6108 (8.4%) had an incident elevated BP during the study period. Among 6108 with an incident elevated BP, 20.9% had a repeat BP measured within 1 month. In multivariate analyses, having a follow-up BP within 1 month was not significantly more likely among individuals with obesity or stage 2 systolic elevation. Among 6108 individuals with an incident elevated BP, 84 (1.4%) had a second and third consecutive elevated BP within 12 months. Whereas >8% of children and adolescents had an incident elevated BP, the great majority of BPs were not repeated within 1 month. However, relatively few individuals subsequently met the definition of hypertension.

  4. Elevated arterial blood pressure after superior cavo-pulmonary anastomosis is associated with elevated pulmonary artery pressure and cerebrovascular dysautoregulation.

    Science.gov (United States)

    Cabrera, Antonio G; Kibler, Kathleen K; Blaine Easley, R; Goldsworthy, Michelle; Shekerdemian, Lara S; Andropoulos, Dean B; Heinle, Jeffrey; Gottlieb, Erin A; Vu, Eric; Brady, Ken M

    2018-04-18

    BackgroundElevated arterial blood pressure (ABP) is common after superior bidirectional cavopulmonary anastomosis (BCPA). The effects of elevated ABP after BCPA on cerebrovascular hemodynamics are unknown. We sought to determine the relationship between elevated ABP and cerebrovascular autoregulation after BCPA.MethodsProspective, observational study on infants with single-ventricle physiology after BCPA surgery. Continuous recordings of mean ABP, mean cavopulmonary artery pressure (PAP), near-infrared spectroscopy measures of cerebral oximetry (regional cerebral oxygen saturation (rSO 2 )), and relative cerebral blood volume index were obtained from admission to extubation. Autoregulation was measured as hemoglobin volume index (HVx). Physiologic variables, including the HVx, were tested for variance across ABP.ResultsSixteen subjects were included in the study. Elevated ABP post-BCPA was associated with both, elevated PAP (PABP and alterations in rSO 2 . Using piecewise regression, the relationship of PAP to ABP demonstrated a breakpoint at 68 mm Hg (interquartile range (IQR) 62-70 mm Hg). Curve fit of HVx as a function of ABP identified optimal ABP supporting robust autoregulation at a median ABP of 55 mm Hg (IQR 51-64 mm Hg).ConclusionsElevated ABP post-BCPA is associated with cerebrovascular dysautoregulation, and elevated PAP. The effects, of prolonged dysautoregulation within this population, require further study.Pediatric Research advance online publication, 18 April 2018; doi:10.1038/pr.2018.31.

  5. Miniature Coplanar Implantable Antenna on Thin and Flexible Platform for Fully Wireless Intracranial Pressure Monitoring System

    Directory of Open Access Journals (Sweden)

    M. Waqas A. Khan

    2017-01-01

    Full Text Available Minimally invasive approach to intracranial pressure monitoring is desired for long-term diagnostics. The monitored pressure is transmitted outside the skull through an implant antenna. We present a new miniature (6 mm × 5 mm coplanar implant antenna and its integration on a sensor platform to establish a far-field data link for the sensor readout at distances of 0.5 to 1 meter. The implant antenna was developed using full-wave electromagnetic simulator and measured in a liquid phantom mimicking the dielectric properties of the human head. It achieved impedance reflection coefficient better than −10 dB from 2.38 GHz to 2.54 GHz which covers the targeted industrial, scientific, and medical band. Experiments resulted in an acceptable peak gain of approximately −23 dBi. The implant antenna was submerged in the liquid phantom and interfaced to a 0.5 mW voltage controlled oscillator. To verify the implant antenna performance as a part of the ICP monitoring system, we recorded the radiated signal strength using a spectrum analyzer. Using a half-wavelength dipole as the receiving antenna, we captured approximately −58.7 dBm signal at a distance of 1 m from the implant antenna which is well above for the reader with sensitivity of −80 dBm.

  6. An Embedded Device for Real-Time Noninvasive Intracranial Pressure Estimation.

    Science.gov (United States)

    Matthews, Jonathan M; Fanelli, Andrea; Heldt, Thomas

    2018-01-01

    The monitoring of intracranial pressure (ICP) is indicated for diagnosing and guiding therapy in many neurological conditions. Current monitoring methods, however, are highly invasive, limiting their use to the most critically ill patients only. Our goal is to develop and test an embedded device that performs all necessary mathematical operations in real-time for noninvasive ICP (nICP) estimation based on a previously developed model-based approach that uses cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) waveforms. The nICP estimation algorithm along with the required preprocessing steps were implemented on an NXP LPC4337 microcontroller unit (MCU). A prototype device using the MCU was also developed, complete with display, recording functionality, and peripheral interfaces for ABP and CBFV monitoring hardware. The device produces an estimate of mean ICP once per minute and performs the necessary computations in 410 ms, on average. Real-time nICP estimates differed from the original batch-mode MATLAB implementation of theestimation algorithm by 0.63 mmHg (root-mean-square error). We have demonstrated that real-time nICP estimation is possible on a microprocessor platform, which offers the advantages of low cost, small size, and product modularity over a general-purpose computer. These attributes take a step toward the goal of real-time nICP estimation at the patient's bedside in a variety of clinical settings.

  7. A Novel Intracranial Pressure Readout Circuit for Passive Wireless LC Sensor.

    Science.gov (United States)

    Wang, Fa; Zhang, Xuan; Shokoueinejad, Mehdi; Iskandar, Bermans J; Medow, Joshua E; Webster, John G

    2017-10-01

    We present a wide frequency range, low cost, wireless intracranial pressure monitoring system, which includes an implantable passive sensor and an external reader. The passive sensor consists of two spiral coils and transduces the pressure change to a resonant frequency shift. The external portable reader reads out the sensor's resonant frequency over a wide frequency range (35 MHz-2.7 GHz). We propose a novel circuit topology, which tracks the system's impedance and phase change at a high frequency with low-cost components. This circuit is very simple and reliable. A prototype has been developed, and measurement results demonstrate that the device achieves a suitable measurement distance (>2 cm), sufficient sample frequency (>6 Hz), fine resolution, and good measurement accuracy for medical practice. Responsivity of this prototype is 0.92 MHz/mmHg and resolution is 0.028 mmHg. COMSOL specific absorption rate simulation proves that this system is safe. Considerations to improve the device performance have been discussed, which include the size of antenna, the power radiation, the Analog-to-digital converter (ADC) choice, and the signal processing algorithm.

  8. Measurement of rock properties at elevated pressures and temperatures

    International Nuclear Information System (INIS)

    Pincus, H.J.; Hoskins, E.R.

    1985-01-01

    The papers in this volume were presented at an ASTM symposium held on 20 June 1983 in conjunction with the 24th Annual Rock Mechanics Symposium at Texas A and M University, College Station, TX. The purpose of these papers is to present recent developments in the measurement of rock properties at elevated pressures and temperatures, and to examine and interpret the data produced by such measurement. The need for measuring rock properties at elevated pressures and temperatures has become increasingly important in recent years. Location and design of nuclear waste repositories, development of geothermal energy sites, and design and construction of deep excavations for civil, military, and mining engineering require significantly improved capabilities for measuring rock properties under conditions substantially different from those prevailing in most laboratory and in situ work. The development of high-pressure, high-temperature capabilities is also significant for the analysis of tectonic processes

  9. Reciprocal Influence of Slow Waves Extracted in Intracranial Pressure, Arterial Pressure and Cerebral Blood Velocity Signals

    National Research Council Canada - National Science Library

    Cervenansky, F

    2001-01-01

    ...), and arterial blood pressure (ABP). To clarify the links, we compared two frequency methods based on coherence function to estimate the influence of ICP, ABP, and CBV on couples, respectively CBV-ABP, ICP-CBV and ICP-ABP, of slow waves...

  10. Investigating Soot Morphology in Counterflow Flames at Elevated Pressures

    KAUST Repository

    Amin, Hafiz Muhammad Fahid

    2018-01-01

    Practical combustion devices such as gas turbines and diesel engines operate at high pressures to increase their efficiency. Pressure significantly increases the overall soot yield. Morphology of these ultra-fine particles determines their airborne lifetime and their interaction with the human respiratory system. Therefore, investigating soot morphology at high pressure is of practical relevance. In this work, a novel experimental setup has been designed and built to study the soot morphology at elevated pressures. The experimental setup consists of a pressure vessel, which can provide optical access from 10° to 165° for multi-angle light scattering, and a counterflow burner which produces laminar flames at elevated pressures. In the first part of the study, N2-diluted ethylene/air and ethane air counterflow flames are stabilized from 2 to 5 atm. Two-angle light scattering and extinction technique have been used to study the effects of pressure on soot parameters. Path averaged soot volume fraction is found to be very sensitive to pressure and increased significantly from 2 to 5 atm. Primary particle size and aggregate size also increased with pressure. Multi-angle light scattering is also performed and flames are investigated from 3 to 5 atm. Scattering to absorption ratio is calculated from multi-angle light scattering and extinction data. Scattering to absorption ratio increased with pressure whereas the number of primary particles in an aggregate decreased with increasing pressure. In the next part of the study, Thermophoretic Sampling of soot is performed, in counterflow flames from 3 to 10 atm, followed by transmission electron microscopy. Mean primary particle size increased with pressure and these trends are consistent withour light scattering measurements. Fractal properties of soot aggregates are found to be insensitive to pressure. 2D diffused light line of sight attenuation (LOSA) and Laser Induced Incandescence (LII) are used to measure local soot

  11. Intracranial pressure-induced optic nerve sheath response as a predictive biomarker for optic disc edema in astronauts.

    Science.gov (United States)

    Wostyn, Peter; De Deyn, Peter Paul

    2017-11-01

    A significant proportion of the astronauts who spend extended periods in microgravity develop ophthalmic abnormalities. Understanding this syndrome, called visual impairment and intracranial pressure (VIIP), has become a high priority for National Aeronautics and Space Administration, especially in view of future long-duration missions (e.g., Mars missions). Moreover, to ensure selection of astronaut candidates who will be able to complete long-duration missions with low risk of the VIIP syndrome, it is imperative to identify biomarkers for VIIP risk prediction. Here, we hypothesize that the optic nerve sheath response to alterations in intracranial pressure may be a potential predictive biomarker for optic disc edema in astronauts. If confirmed, this biomarker could be used for preflight identification of astronauts at risk for developing VIIP-associated optic disc edema.

  12. Intracranial hypertension prediction using extremely randomized decision trees.

    Science.gov (United States)

    Scalzo, Fabien; Hamilton, Robert; Asgari, Shadnaz; Kim, Sunghan; Hu, Xiao

    2012-10-01

    Intracranial pressure (ICP) elevation (intracranial hypertension, IH) in neurocritical care is typically treated in a reactive fashion; it is only delivered after bedside clinicians notice prolonged ICP elevation. A proactive solution is desirable to improve the treatment of intracranial hypertension. Several studies have shown that the waveform morphology of the intracranial pressure pulse holds predictors about future intracranial hypertension and could therefore be used to alert the bedside clinician of a likely occurrence of the elevation in the immediate future. In this paper, a computational framework is proposed to predict prolonged intracranial hypertension based on morphological waveform features computed from the ICP. A key contribution of this work is to exploit an ensemble classifier method based on extremely randomized decision trees (Extra-Trees). Experiments on a representative set of 30 patients admitted for various intracranial pressure related conditions demonstrate the effectiveness of the predicting framework on ICP pulses acquired under clinical conditions and the superior results of the proposed approach in comparison to linear and AdaBoost classifiers. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  13. Intracranial Pressure-Guided Shunt Valve Adjustments with the Miethke Sensor Reservoir.

    Science.gov (United States)

    Antes, Sebastian; Stadie, Axel; Müller, Simon; Linsler, Stefan; Breuskin, David; Oertel, Joachim

    2018-01-01

    Telemetric intracranial pressure (ICP) monitoring seems to be a promising therapy-supporting option in shunt-treated patients. Benefits become obvious when headaches are unspecific and clinical symptoms cannot be related to possible overdrainage or underdrainage. In this study, we evaluated a new telemetric device to individually adjust shunt valves according to ICP measurements. Between December 2015 and November 2016, 25 patients with suspected suboptimal shunt valve settings underwent insertion of a telemetric ICP sensor (Sensor Reservoir; Christoph Miethke, Potsdam, Germany). Over a 1-year period, a total of 183 telemetric ICP measurements and 85 shunt valve adjustments were carried out. Retrospective statistic analyses focused on valve adjustments, ICP values, and clinical outcomes. ICP-guided valve adjustments positively changed the clinical state in 18 out of 25 patients. Clinical improvement over time was associated with significant changes of the valve settings and ICP values. Interestingly, a therapeutically normalized ICP profile was not automatically associated with clinical improvement. The Sensor Reservoir is an important and valuable tool for shunt-treated patients suffering from drainage-related problems. The possibility to simultaneously recognize and solve shunt problems represents the decisive advantage. Nevertheless, measurements with the Sensor Reservoir did not allow for the determination of default valve settings or universal target ICP values. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. [Intracranial pressure monitoring and CSF dynamics in patients with neurological disorders: indications and practical considerations].

    Science.gov (United States)

    Poca, M; Sahuquillo, J

    2001-01-01

    The study of cerebrospinal fluid (CSF) dynamics is central to the diagnosis of adult chronic hydrocephalus (ACH). At present, many neurology and neurosurgery departments use one or more tests to guide diagnosis of this syndrome and to predict patient response to shunting. In specialised centres, the study of CSF dynamics is combined with continuous intracranial pressure (ICP) monitoring. Determination of several variables of CSF dynamics and definitions of qualitative and quantitative characteristics of ICP can be used to establish whether the hydrocephalus is active, compensated or arrested. CSF dynamics and ICP monitoring can also be used to check the correct functioning of the shunt and can be of use in the clinical management of patients with pseudotumor cerebri. Moreover, ICP monitoring is used to guide the treatment of several acute neurological processes. The aim of this review is to describe the fundamentals of CSF dynamics studies and the bases of continuous ICP monitoring. The advantages and disadvantages of several hydrodynamic tests that can be performed by lumbar puncture, as well as the normal and abnormal characteristics of an ICP recording, are discussed.

  15. NASA's Current Evidence and Hypothesis for the Visual Impairment and Intracranial Pressure Risk

    Science.gov (United States)

    Otto, Christian A.; Norsk, Peter; Oubre, Cherie M.; Pass, Anastas F.; Tarver, William

    2012-01-01

    While 40 years of human spaceflight exploration has reported visual decrement to a certain extent in a subgroup of astronauts, recent data suggests that there is indeed a subset of crewmembers that experience refraction changes (hyperoptic shift), cotton wool spot formation, choroidal fold development, papilledema, optic nerve sheath distention and/or posterior globe flattening with varying degrees of severity and permanence. Pre and postflight ocular measures have identified a potential risk of permanent visual changes as a result of microgravity exposure, which has been defined as the Visual Impairment and Intracranial Pressure risk (VIIP). The combination of symptoms are referred to as the VIIP syndrome. It is thought that the ocular structural and optic nerve changes are caused by events precipitated by the cephalad fluid shift crewmembers experience during long-duration spaceflight. Three important systems, ocular, cardiovascular, and central nervous, seem to be involved in the development of symptoms, but the etiology is still under speculation. It is believed that some crewmembers are more susceptible to these changes due to genetic/anatomical predisposition or lifestyle (fitness) related factors. Future research will focus on determining the etiology of the VIIP syndrome and development of mechanisms to mitigate the spaceflight risk.

  16. The effect of head-down tilt and water immersion on intracranial pressure in nonhuman primates

    Science.gov (United States)

    Keil, Lanny C.; Mckeever, Kenneth H.; Skidmore, Michael G.; Hines, John; Severs, Walter B.

    1992-01-01

    Intracranial pressure (ICP) is investigated in primates during and after -6-deg head-down tilt (HDT) and immersion in water to examine the effects of the headward fluid shift related to spaceflight. Following the HDT the primates are subjected to head-out thermoneutral water immersion, and the ICP is subsequently measured. ICP is found to increase from 3.8 +/- 1.1 to 5.3 +/- 1.3 mm Hg during the horizontal control period. ICP stabilizes at -6.3 +/- 1.3 mm Hg and then increases to -2.2 +/- 1.9 mm Hg during partial immersion, and ICP subsequently returns to preimmersion levels after immersion. These data indicate that exposure to HDT or water immersion lead to an early sharp increase in ICP, and water immersion alone leads to higher ICP levels. A significant conclusion of the work is that the ICP did not approach pathological levels, and this finding is relevant to human spaceflight research.

  17. Intracranial pressure monitoring in severe blunt head trauma: does the type of monitoring device matter?

    Science.gov (United States)

    Aiolfi, Alberto; Khor, Desmond; Cho, Jayun; Benjamin, Elizabeth; Inaba, Kenji; Demetriades, Demetrios

    2018-03-01

    OBJECTIVE Intracranial pressure (ICP) monitoring has become the standard of care in the management of severe head trauma. Intraventricular devices (IVDs) and intraparenchymal devices (IPDs) are the 2 most commonly used techniques for ICP monitoring. Despite the widespread use of these devices, very few studies have investigated the effect of device type on outcomes. The purpose of the present study was to compare outcomes between 2 types of ICP monitoring devices in patients with isolated severe blunt head trauma. METHODS This retrospective observational study was based on the American College of Surgeons Trauma Quality Improvement Program database, which was searched for all patients with isolated severe blunt head injury who had an ICP monitor placed in the 2-year period from 2013 to 2014. Extracted variables included demographics, comorbidities, mechanisms of injury, head injury specifics (epidural, subdural, subarachnoid, intracranial hemorrhage, and diffuse axonal injury), Abbreviated Injury Scale (AIS) score for each body area, Injury Severity Score (ISS), vital signs in the emergency department, and craniectomy. Outcomes included 30-day mortality, complications, number of ventilation days, intensive care unit and hospital lengths of stay, and functional independence. RESULTS During the study period, 105,721 patients had isolated severe traumatic brain injury (head AIS score ≥ 3). Overall, an ICP monitoring device was placed in 2562 patients (2.4%): 1358 (53%) had an IVD and 1204 (47%) had an IPD. The severity of the head AIS score did not affect the type of ICP monitoring selected. There was no difference in the median ISS; ISS > 15; head AIS Score 3, 4, or 5; or the need for craniectomy between the 2 device groups. Unadjusted 30-day mortality was significantly higher in the group with IVDs (29% vs 25.5%, p = 0.046); however, stepwise logistic regression analysis showed that the type of ICP monitoring was not an independent risk factor for death

  18. Quantitative relations between the eyeball, the optic nerve, and the optic canal important for intracranial pressure monitoring.

    Science.gov (United States)

    Vaiman, Michael; Gottlieb, Paul; Bekerman, Inessa

    2014-08-17

    To find correlations between diameters of the optic nerve sheath (ONSD), the eyeball, and the optic canal that might be important for intracranial pressure monitoring. In a prospective cohort study, the CT data of consecutive 400 adults (18+) with healthy eyes and optic nerves and absence of neurological diseases were collected and analyzed. When the CT scans were obtained, the diameters of the optic nerve sheath, the eyeball, and the optic canal were measured and statistically analyzed. The data obtained from the left and from the right eyeballs and optic nerves were compared. The correlation analysis was performed within these variables, with the gender, and the age. In healthy persons, the ONSD varies from 3.65 mm to 5.17 mm in different locations within the intraorbital space with no significant difference between sexes and age groups. There is a strong correlation between the eyeball transverse diameter (ETD) and ONSD that can be presented as ONSD/ETD index. In healthy subjects, the ONSD/ETD index equals 0.19. The calculation of an index when ONSD is divided by the ETD of the eyeball presents precise normative database for ONSD intracranial pressure measurement technique. When the ONSD is measured for intracranial pressure monitoring, the most stable results can be obtained if the diameter is measured 10 mm from the globe. These data might serve as a normative database at emergency departments and in general neurological practice.

  19. On Boiling of Crude Oil under Elevated Pressure

    Science.gov (United States)

    Pimenova, Anastasiya V.; Goldobin, Denis S.

    2016-02-01

    We construct a thermodynamic model for theoretical calculation of the boiling process of multicomponent mixtures of hydrocarbons (e.g., crude oil). The model governs kinetics of the mixture composition in the course of the distillation process along with the boiling temperature increase. The model heavily relies on the theory of dilute solutions of gases in liquids. Importantly, our results are applicable for modelling the process under elevated pressure (while the empiric models for oil cracking are not scalable to the case of extreme pressure), such as in an oil field heated by lava intrusions.

  20. Can sonographic measurement of optic nerve sheath diameter be used to detect raised intracranial pressure in patients with tuberculous meningitis? A prospective observational study

    International Nuclear Information System (INIS)

    Sangani, Shruti V; Parikh, Samira

    2015-01-01

    CNS Tuberculosis can manifest as meningitis, arachnoiditis and a tuberculoma. The rupture of a tubercle into the subarachnoid space leads to Tuberculosis Meningitis (TBME); the resulting hypersensitivity reaction can lead to an elevation of the intracranial pressure and hydrocephalus. While bedside optic nerve sheath diameter (ONSD) ultrasonography (USG) can be a sensitive screening test for elevated intracranial pressure in adult head injury, little is known regarding ONSD measurements in Tuberculosis Meningitis. The aim of this study was to determine whether patients with TBME had dilation of the optic nerve sheath, as detected by ocular USG performed in the emergency department (ED). We conducted a prospective, observational study on adult ED patients with suspected TBME. Patients underwent USG measurements of the optic nerve followed by MRI. The ONSD was measured 3 mm behind the globe in each eye. MRI evidence of basilar meningeal enhancement and any degree of hydrocephalus was suggestive of TBME. Those patients without evidence of hydrocephalus subsequently underwent a lumbar puncture to confirm the diagnosis. Exclusion criteria were age less than 18 and obvious ocular pathology. In total, the optic nerve sheath diameters of 25 adults with confirmed TBME were measured. These measurements were compared with 120 control patients. The upper limit of normal ONSD was 4.37 mm in control group. Those patients with TBME had a mean ONSD of 5.81 mm (SD 0.42). These results confirm that patients with tuberculosis meningitis have an ONSD in excess of the control data (P < 0.001). The evaluation of the ONSD is a simple non-invasive and potentially useful tool in the assessment of adults suspected of having TBME

  1. Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods.

    Science.gov (United States)

    Cardim, Danilo; Robba, Chiara; Donnelly, Joseph; Bohdanowicz, Michal; Schmidt, Bernhard; Damian, Maxwell; Varsos, Georgios V; Liu, Xiuyun; Cabeleira, Manuel; Frigieri, Gustavo; Cabella, Brenno; Smielewski, Peter; Mascarenhas, Sergio; Czosnyka, Marek

    2016-04-15

    Elevation of intracranial pressure (ICP) may occur in many diseases, and therefore the ability to measure it noninvasively would be useful. Flow velocity signals from transcranial Doppler (TCD) have been used to estimate ICP; however, the relative accuracy of these methods is unclear. This study aimed to compare four previously described TCD-based methods with directly measured ICP in a prospective cohort of traumatic brain-injured patients. Noninvasive ICP (nICP) was obtained using the following methods: 1) a mathematical "black-box" model based on interaction between TCD and arterial blood pressure (nICP_BB); 2) based on diastolic flow velocity (nICP_FVd); 3) based on critical closing pressure (nICP_CrCP); and 4) based on TCD-derived pulsatility index (nICP_PI). In time domain, for recordings including spontaneous changes in ICP greater than 7 mm Hg, nICP_PI showed the best correlation with measured ICP (R = 0.61). Considering every TCD recording as an independent event, nICP_BB generally showed to be the best estimator of measured ICP (R = 0.39; p area under the curve [AUC] = 0.66; p AUC (0.70; p AUC = 0.64; p > 0.05). nICP_PI was not related to measured ICP using any of the above statistical indicators. We also introduced a new estimator (nICP_Av) based on the average of three methods (nICP_BB, nICP_FVd, and nICP_CrCP), which overall presented improved statistical indicators (R = 0.47; p AUC = 0.73; p < 0.05). nICP_PI appeared to reflect changes in ICP in time most accurately. nICP_BB was the best estimator for ICP "as a number." nICP_Av demonstrated to improve the accuracy of measured ICP estimation.

  2. System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure.

    Directory of Open Access Journals (Sweden)

    Max A Stockslager

    Full Text Available Pathologic changes in intracranial pressure (ICP are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation.

  3. Semi-supervised detection of intracranial pressure alarms using waveform dynamics

    International Nuclear Information System (INIS)

    Scalzo, Fabien; Hu, Xiao

    2013-01-01

    Patient monitoring systems in intensive care units (ICU) are usually set to trigger alarms when abnormal values are detected. Alarms are generated by threshold-crossing rules that lead to high false alarm rates. This is a recognized issue that causes alarm fatigue, waste of human resources, and increased patient risks. Recently developed smart alarm models require alarms to be validated by experts during the training phase. The manual annotation process involved is time-consuming and virtually impossible to achieve for the thousands of alarms recorded in the ICU every week. To tackle this problem, we investigate in this study if the use of semi-supervised learning methods, that can naturally integrate unlabeled data samples in the model, can be used to improve the accuracy of the alarm detection. As a proof of concept, the detection system is evaluated on intracranial pressure (ICP) signal alarms. Specific morphological and trending features are extracted from the ICP signal waveform to capture the dynamic of the signal prior to alarms. This study is based on a comprehensive dataset of 4791 manually labeled alarms recorded from 108 neurosurgical patients. A comparative analysis is provided between kernel spectral regression (SR-KDA) and support vector machine (SVM) both modified for the semi-supervised setting. Results obtained during the experimental evaluations indicate that the two models can significantly reduce false alarms using unlabeled samples; especially in the presence of a restrained number of labeled examples. At a true alarm recognition rate of 99%, the false alarm reduction rates improved from 9% (supervised) to 27% (semi-supervised) for SR-KDA, and from 3% (supervised) to 16% (semi-supervised) for SVM. (paper)

  4. Optic nerve sheath diameter on fat-saturated T2-weighted orbital MR imaging reflects intracranial pressure

    International Nuclear Information System (INIS)

    Watanabe, Arata; Kinouchi, Hiroyuki; Horikoshi, Toru; Uchida, Mikito; Sakatsume, Satoshi

    2009-01-01

    Although dilated optic nerve sheath (ONS) is observed in the setting of increased intracranial pressure (ICP) such as idiopathic intracranial hypertension or hydrocephalus, the relationship between ONS diameter and ICP is unclear. We analyzed the relationship between subdural pressure measured during surgery in patients with chronic subdural fluid collections and ONS diameter measured on MR images. Orbital thin slice fat-saturated MR images were obtained within 24 hours before surgery and ONS diameters were measured just behind the optic globe. Subdural pressure was measured using a manometer before opening the dura mater during surgery. Significant correlation was found between the ONS diameter and subdural pressure (y=0.0618x+4.8219. y: ONS diameter (mm), x: subdural pressure (cmH 2 O), correlation coefficient: 0.505). The ONS diameter before surgery (6.1±0.7 mm) was significantly reduced after surgery (4.8±0.9 mm, p=0.003). Increased ONS diameter on MR images is a strong indicator of increased ICP we propose 6 mm as the normal limit of diameter just behind the eyeball because this value corresponds to the upper normal limit of ICP of around 20 cmH 2 O with above mentioned approximate curve. (author)

  5. Intracranial Monitoring after Severe Traumatic Brain Injury

    OpenAIRE

    Donnelly, Joseph

    2018-01-01

    Intracranial monitoring after severe traumatic brain injury offers the possibility for early detection and amelioration of physiological insults. In this thesis, I explore cerebral insults due raised intracranial pressure, decreased cerebral perfusion pressure and impaired cerebral pressure reactivity after traumatic brain injury. In chapter 2, the importance of intracranial pressure, cerebral perfusion pressure and pressure reactivity in regulating the cerebral circulation is elucidated ...

  6. Elevated cerebrospinal fluid pressure in patients with Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Fellmann Jere

    2006-05-01

    Full Text Available Abstract Background Abnormalities in cerebrospinal fluid (CSF production and turnover, seen in normal pressure hydrocephalus (NPH and in Alzheimer's disease (AD, may be an important cause of amyloid retention in the brain and may relate the two diseases. There is a high incidence of AD pathology in patients being shunted for NPH, the AD-NPH syndrome. We now report elevated CSF pressure (CSFP, consistent with very early hydrocephalus, in a subset of AD patients enrolled in a clinical trial of chronic low-flow CSF drainage. Our objective was to determine the frequency of elevated CSFP in subjects meeting National Institutes of Neurological and Communicative Diseases and Stroke – Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA criteria for AD, excluding those with signs of concomitant NPH. Methods AD subjects by NINCDS-ADRDA criteria (n = 222, were screened by history, neurological examination, and radiographic imaging to exclude those with clinical or radiographic signs of NPH. As part of this exclusion process, opening CSFP was measured supine under general anesthesia during device implantation surgery at a controlled pCO2 of 40 Torr (40 mmHg. Results Of the 222 AD subjects 181 had pressure measurements recorded. Seven subjects (3.9% enrolled in the study had CSFP of 220 mmH20 or greater, mean 249 ± 20 mmH20 which was significantly higher than 103 ± 47 mmH2O for the AD-only group. AD-NPH patients were significantly younger and significantly less demented on the Mattis Dementia Rating Scale (MDRS. Conclusion Of the AD subjects who were carefully screened to exclude those with clinical NPH, 4% had elevated CSFP. These subjects were presumed to have the AD-NPH syndrome and were withdrawn from the remainder of the study.

  7. A fluid-structure interaction model of the internal carotid and ophthalmic arteries for the noninvasive intracranial pressure measurement method.

    Science.gov (United States)

    Misiulis, Edgaras; Džiugys, Algis; Navakas, Robertas; Striūgas, Nerijus

    2017-05-01

    Accurate and clinically safe measurements of intracranial pressure (ICP) are crucial for secondary brain damage prevention. There are two methods of ICP measurement: invasive and noninvasive. Invasive methods are clinically unsafe; therefore, safer noninvasive methods are being developed. One of the noninvasive ICP measurement methods implements the balance principle, which assumes that if the velocity of blood flow in both ophthalmic artery segments - the intracranial (IOA) and extracranial (EOA) - is equal, then the acting ICP on the IOA and the external pressure (Pe) on the EOA are also equal. To investigate the assumption of the balance principle, a generalized computational model incorporating a fluid-structure interaction (FSI) module was created and used to simulate noninvasive ICP measurement by accounting for the time-dependent behavior of the elastic internal carotid (ICA) and ophthalmic (OA) arteries and their interaction with pulsatile blood flow. It was found that the extra balance pressure term, which incorporates the hydrodynamic pressure drop between measurement points, must be added into the balance equation, and the corrections on a difference between the velocity of blood flow in the IOA and EOA must be made, due to a difference in the blood flow rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. The effect of acetazolamide on cerebral blood volume and intracranial pressure in patients with hydrocephalus. Theoretical background of the acetazolamide challenge test

    International Nuclear Information System (INIS)

    Ogawa, Daiji

    2000-01-01

    The acetazolamide challenge test is one of the useful tests for diagnosing normal pressure hydrocephalus (NPH). It has the advantage of being less invasive than other tests. However, the manner of increment in cerebral blood volume (CBV) has not been well clarified. Therefore, the theoretical background of the test is also unclear. The aims of this study were to evaluate the effect of acetazolamide on CBV and intracranial pressure (ICP) and elucidate the theoretical background of the test. Thirteen patients with NPH were studied. CBV and ICP were measured before and after the intravenous injection of acetazolamide (1000 mg). CBV was evaluated by means of cerebral pool SPECT; ICP was evaluated by OSAKA telesensor or a pressure transducer via ventricular catheter. Immediately after the injection, CBV increased rapidly, reaching its maximum (15% increase) at 6 minutes. Then CBV gradually decreased. ICP also elevated rapidly, reaching its maximum (12.6 mmHg elevation) at 4 minutes. A gradual decrement ICP was observed, and 26 minutes after injection, the ICP became lower than the pre-injection level. The rapid increase in CBV caused the ICP elevation, and the increment ratio reflected the cerebral compliance. Therefore, we concluded that the acetazolamide challenge test is based on the alteration of cerebral compliance seen in NPH patients. The decrement ratio of ICP is affected not only by the resistance cerebrospinal fluid (CSF) absorption but also by decrease in the CBV and CSF production induced by acetazolamide. Consequently, it is difficult to evaluate the resistance of CSF absorption by this test. Because CBV increased in all cases, it is assumed that acetazolamide administration can be used to reliably load the volume. (author)

  9. Intracranial Hemorrhage

    Science.gov (United States)

    2011-01-01

    Intracranial hemorrhage is a life-threatening condition, the outcome of which can be improved by intensive care. Intracranial hemorrhage may be spontaneous, precipitated by an underlying vascular malformation, induced by trauma, or related to therapeutic anticoagulation. The goals of critical care are to assess the proximate cause, minimize the risks of hemorrhage expansion through blood pressure control and correction of coagulopathy, and obliterate vascular lesions with a high risk of acute rebleeding. Simple bedside scales and interpretation of computed tomography scans assess the severity of neurological injury. Myocardial stunning and pulmonary edema related to neurological injury should be anticipated, and can usually be managed. Fever (often not from infection) is common and can be effectively treated, although therapeutic cooling has not been shown to improve outcomes after intracranial hemorrhage. Most functional and cognitive recovery takes place weeks to months after discharge; expected levels of functional independence (no disability, disability but independence with a device, dependence) may guide conversations with patient representatives. Goals of care impact mortality, with do-not-resuscitate status increasing the predicted mortality for any level of severity of intraparenchymal hemorrhage. Future directions include refining the use of bedside neuromonitoring (electroencephalogram, invasive monitors), novel approaches to reduce intracranial hemorrhage expansion, minimizing vasospasm, and refining the assessment of quality of life to guide rehabilitation and therapy. PMID:22167847

  10. Diffusion tensor imaging detects early brain microstructure changes before and after ventriculoperitoneal shunt in children with high intracranial pressure hydrocephalus

    Science.gov (United States)

    Zhao, Cailei; Li, Yongxin; Cao, Weiguo; Xiang, Kui; Zhang, Heye; Yang, Jian; Gan, Yungen

    2016-01-01

    Abstract To explore the use of diffusion tensor imaging (DTI) parameters in the quantitative assessment of early brain microstructure changes before and after ventriculoperitoneal shunt in children with high intracranial pressure hydrocephalus. Ten patients with communicating hydrocephalus (age: 2–36 months) and 14 age-/gender-matched controls (age: 2–36 months) were enrolled in this study. All patients underwent the ventriculoperitoneal shunt procedure. The imaging data were collected before and 3 months after the operation. Regions of interests (ROIs) included the white matter near the frontal horn of the lateral ventricles (FHLV), the occipital horn of the lateral ventricles (OHLV), occipital subcortical (OS) area, frontal subcortical (FS) area, and thalamus. Fractional anisotropies (FA) and apparent diffusion coefficients (ADC) of the ROIs before and after ventriculoperitoneal shunt were compared between the patients and the controls. Three months after surgery, the patients recovered from the surgery with ameliorated intracranial pressure and slight improvement of clinical intelligence scale and motor scale. Before ventriculoperitoneal shunt, the FA values (except the right FHLV) were significantly decreased and the ADC values were significantly increased in the patients with hydrocephalus, compared with the controls. After the ventriculoperitoneal shunt, the FA values in the FHLV and OHLV of the patients were similar to the controls, but the FA values in other ROIs were still significantly lower than controls. The ADC values in the FS and OS white matter areas of the patients were similar to the controls; however, the ADC values in other ROIs were still significantly higher in patients. The increase of FA and the reduction in ADC in the ROIs preceded the clinical function improvement in patients with high intracranial pressure hydrocephalus and reflected the early changes in brain tissue microstructure, such as the compression of the white matter areas in

  11. Intracranial Pressure Response to Non-Penetrating Ballistic Impact: An Experimental Study Using a Pig Physical Head Model and Live Pigs

    Science.gov (United States)

    Liu, Hai; Kang, Jianyi; Chen, Jing; Li, Guanhua; Li, Xiaoxia; Wang, Jianmin

    2012-01-01

    This study was conducted to characterize the intracranial pressure response to non-penetrating ballistic impact using a "scalp-skull-brain" pig physical head model and live pigs. Forty-eight ballistic tests targeting the physical head model and anesthetized pigs protected by aramid plates were conducted with standard 9 mm bullets at low (279-297 m/s), moderate (350-372 m/s), and high (409-436 m/s) velocities. Intracranial pressure responses were recorded with pressure sensors embedded in similar brain locations in the physical head model and the anesthetized pigs. Three parameters of intracranial pressure were determined from the measured data: intracranial maximum pressure (Pmax), intracranial maximum pressure impulse (PImax), and the duration of the first positive phase (PPD). The intracranial pressure waves exhibited blast-like characteristics for both the physical model and l live pigs. Of all three parameters, Pmax is most sensitive to impact velocity, with means of 126 kPa (219 kPa), 178 kPa (474 kPa), and 241 kPa (751 kPa) for the physical model (live pigs) for low, moderate, and high impact velocities, respectively. The mean PPD becomes increasingly short as the impact velocity increases, whereas PImax shows the opposite trend. Although the pressure parameters of the physical model were much lower than those of the live pigs, good correlations between the physical model and the live pigs for the three pressure parameters, especially Pmax, were found using linear regression. This investigation suggests that Pmax is a preferred parameter for predicting the severity of the brain injury resulting from behind armor blunt trauma (BABT). PMID:23055817

  12. Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury

    DEFF Research Database (Denmark)

    Lund, Anton; Damholt, Mette B; Strange, Ditte G

    2017-01-01

    Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strateg...

  13. Assessment of the usability of a digital learning technology prototype for monitoring intracranial pressure.

    Science.gov (United States)

    Carvalho, Lilian Regina de; Évora, Yolanda Dora Martinez; Zem-Mascarenhas, Silvia Helena

    2016-08-29

    to assess the usability of a digital learning technology prototype as a new method for minimally invasive monitoring of intracranial pressure. descriptive study using a quantitative approach on assessing the usability of a prototype based on Nielsen's ten heuristics. Four experts in the area of Human-Computer interaction participated in the study. the evaluation delivered eight violated heuristics and 31 usability problems in the 32 screens of the prototype. the suggestions of the evaluators were critical for developing an intuitive, user-friendly interface and will be included in the final version of the digital learning technology. avaliar a usabilidade de um protótipo educacional digital sobre um novo método para monitoração da pressão intracraniana de forma minimamente invasivo para enfermeiros e médicos. estudo descritivo com abordagem quantitativa sobre a avaliação de usabilidade de um protótipo com base nas dez Heurísticas de Nielsen. Participaram quatro especialistas da área de Interação Humano Computador. a avaliação resultou em oito heurísticas violadas e 31 problemas de usabilidade nas 32 telas do protótipo. as sugestões dos avaliadores foram cruciais para o desenvolvimento de uma interface amigável e intuitiva e serão consideradas na versão final da tecnologia educacional digital. evaluar la usabilidad de un prototipo educacional digital sobre un nuevo método para monitorización de la presión intracraneal, de manera mínimamente invasiva. estudio descriptivo con abordaje cuantitativo sobre la evaluación de usabilidad de un prototipo con base en las diez reglas Heurísticas de Nielsen. Participaron cuatro especialistas del área de Interacción Humana Computador. la evaluación resultó en ocho reglas heurísticas violadas y 31 problemas de usabilidad en las 32 pantallas del prototipo. las sugestiones de los evaluadores fueron cruciales para el desarrollo de una interfaz amigable e intuitiva y éstas serán consideradas en la

  14. Burst pressure of super duplex stainless steel pipes subject to combined axial tension, internal pressure and elevated temperature

    International Nuclear Information System (INIS)

    Lasebikan, B.A.; Akisanya, A.R.

    2014-01-01

    The burst pressure of super duplex stainless steel pipe is measured under combined internal pressure, external axial tension and elevated temperature up to 160 °C. The experimental results are compared with existing burst pressure prediction models. Existing models are found to provide reasonable estimate of the burst pressure at room temperature but significantly over estimate the burst pressure at elevated temperature. Increasing externally applied axial stress and elevated temperature reduces the pressure capacity. - Highlights: • The burst pressure of super duplex steel is measured under combined loading. • Effect of elevated temperature on burst pressure is determined. • Burst pressure decreases with increasing temperature. • Existing models are reliable at room temperature. • Burst strength at elevated temperature is lower than predictions

  15. Evaluation Of Liner Back-pressure Due To Concrete Pore Pressure At Elevated Temperatures

    International Nuclear Information System (INIS)

    James, R.J.; Rashid, Y.R.; Liu, A.S.; Gou, B.

    2006-01-01

    GE's latest evolution of the boiling water reactor, the ESBWR, has innovative passive design features that reduce the number and complexity of active systems, which in turn provide economic advantages while also increasing safety. These passive systems used for emergency cooling also mean that the primary containment system will experience elevated temperatures with longer durations than conventional plants in the event of design basis accidents. During a Loss of Coolant Accident (LOCA), the drywell in the primary containment structure for the ESBWR will be exposed to saturated steam conditions for up to 72 hours following the accident. A containment spray system may be activated that sprays the drywell area with water to condense the steam as part of the recovery operations. The liner back-pressure will build up gradually over the 72 hours as the concrete temperatures increase, and a sudden cool down could cause excessive differential pressure on the liner to develop. For this analysis, it is assumed that the containment spray is activated at the end of the 72-hour period. A back-pressure, acting between the liner and the concrete wall of the containment, can occur as a result of elevated temperatures in the concrete causing steam and saturated vapor pressures to develop from the free water remaining in the pores of the concrete. Additional pore pressure also develops under the elevated temperatures from the non-condensable gases trapped in the concrete pores during the concrete curing process. Any buildup of this pore pressure next to the liner, in excess of the drywell internal pressure, will act to push the liner away from the concrete with a potential for tearing at the liner anchorages. This paper describes the methods and analyses used to quantify this liner back-pressure so that appropriate measures are included in the design of the liner and anchorage system. A pore pressure model is developed that calculates the pressure distribution across the concrete

  16. Reactor pressure elevation preventing device upon interruption of load

    International Nuclear Information System (INIS)

    Ota, Yasuo; Okukawa, Ryutaro.

    1996-01-01

    In a power load imbalance circuit of a steam turbine control device, a power load imbalance occurrence signal is outputted for a predetermined period of time upon occurrence of load interruption. A function for suppressing increase of number of rotation of a turbine due to load interruption is not disturbed, and the power load imbalance circuit is not operated at least after a primary peak where the number of rotation of the turbine is increased. Since a steam control valve flow rate demand signal and a turbine bypass valve flow rate demand signals are corporated subsequently to control the opening degree of the steam control valve and the turbine bypass valve, elevation of reactor pressure is always suppressed and maintained constant, as well as abrupt opening of the steam control valve due to cancel of the power load imbalance circuit when steam control valve opening demand is outputted can be prevented. (N.H.)

  17. Transethmoidal encephalocele after reduction of high intracranial pressure in aqueductal stenosis.

    Science.gov (United States)

    Sharifi, Guive; Alavi, Ehsan; Jalessi, Maryam; Haddadian, Karim; Faramarzi, Faezeh

    2014-01-01

    Acquired non-traumatic transethmoidal encephaloceles are very infrequent lesions that are generally caused by a tumor or hydrocephalus. As far as we know, there is no reported case of encephalocele after CSF diversion in the literature. We present a 25-year-old woman with hydrocephalus due to aquiductal stenosis who was treated with endoscopic third ventriculostomy. Nine months later, she had developed rhinorrhea and on imaging she had a transethmoidal encephalocele. She underwent endonasal endoscopic repair of the defect and removal of herniated parenchyma. CSF diversion to parasellar cisterns is not a known iatrogenic cause of basal encephalocele and is not noted elsewhere as a complication of third ventriculostomy. However, as third ventriculostomy is performed usually for intracranial hypertension treatment and intracranial hypertension itself is a known but rare cause of lacunar skull defect and encephalocele, this co-incidence may occur.

  18. Soot particle size measurements in ethylene diffusion flames at elevated pressures

    KAUST Repository

    Steinmetz, Scott; Fang, Tiegang; Roberts, William L.

    2016-01-01

    for the first time at elevated pressures. Soot volume fraction dependence on pressure is consistent with the observations of similar studies, scaling approximately with the square of pressure. Scattering intensity is analyzed through Rayleigh and Rayleigh

  19. Left ventricular filling under elevated left atrial pressure

    Science.gov (United States)

    Gaddam, Manikantam; Samaee, Milad; Santhanakrishnan, Arvind

    2017-11-01

    Left atrial pressure (LAP) is elevated in diastolic dysfunction, where left ventricular (LV) filling is impaired due to increase in ventricular stiffness. The impact of increasing LAP and LV stiffness on intraventricular filling hemodynamics remains unclear. We conducted particle image velocimetry and hemodynamics measurements in a left heart simulator (LHS) under increasing LAP and LV stiffness at a heart rate of 70 bpm. The LHS consisted of a flexible-walled LV physical model fitted within a fluid-filled chamber. LV wall motion was generated by a piston pump that imparted pressure fluctuations in the chamber. Resistance and compliance elements in the flow loop were adjusted to obtain bulk physiological hemodynamics in the least stiff LV model. Two LV models of increasing stiffness were subsequently tested under unchanged loop settings. LAP was varied between 5-20 mm Hg for each LV model, by adjusting fluid level in a reservoir upstream of the LV. For constant LV stiffness, increasing LAP lowered cardiac output (CO), while ejection fraction (EF) and E/A ratio were increased. For constant LAP, increasing LV stiffness lowered CO and EF, and increased E/A ratio. The implications of these altered hemodynamics on intraventricular filling vortex characteristics will be presented.

  20. Rotating disk electrode system for elevated pressures and temperatures.

    Science.gov (United States)

    Fleige, M J; Wiberg, G K H; Arenz, M

    2015-06-01

    We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H2SO4, the setup can easily be operated in a pressure range of 1-101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells.

  1. Rotating disk electrode system for elevated pressures and temperatures

    International Nuclear Information System (INIS)

    Fleige, M. J.; Wiberg, G. K. H.; Arenz, M.

    2015-01-01

    We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H 2 SO 4 , the setup can easily be operated in a pressure range of 1–101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells

  2. Rotating disk electrode system for elevated pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fleige, M. J.; Wiberg, G. K. H.; Arenz, M. [Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Ø Copenhagen (Denmark)

    2015-06-15

    We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H{sub 2}SO{sub 4}, the setup can easily be operated in a pressure range of 1–101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells.

  3. Rotating disk electrode system for elevated pressures and temperatures

    Science.gov (United States)

    Fleige, M. J.; Wiberg, G. K. H.; Arenz, M.

    2015-06-01

    We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H2SO4, the setup can easily be operated in a pressure range of 1-101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells.

  4. Proximal Limb Weakness Reverting After CSF Diversion In Intracranial Hypertension

    Directory of Open Access Journals (Sweden)

    Sinha S

    2005-01-01

    Full Text Available We report about two young girls who developed progressive visual failure secondary to increased intracranial pressure and had significant proximal muscle weakness of limbs. Patients with elevated intracranial pressure (ICP may present with "false localizing signs", besides having headache, vomiting and papilledema. Radicular pain as a manifestation of raised ICP is rare and motor weakness attributable to polyradiculopathy is exceptional. Two patients with increased intracranial pressure without lateralizing signs′ had singnificant muscle weakness. Clinical evaluation and laboratory tests did not disclose any other cause for weakness. Following theco-peritoneal shunt, in both patients, there was variable recovery of vision but the proximal weakness and symptoms of elevated ICP improved rapidly. Recognition of this uncommon manifestation of raised ICP may obviate the need for unnecessary investigation and reduce morbidity due to weakness by CSF diversion procedure.

  5. Temperature variability in the day-night cycle is associated with further intracranial pressure during therapeutic hypothermia.

    Science.gov (United States)

    Nogueira, Adriano Barreto; Annen, Eva; Boss, Oliver; Farokhzad, Faraneh; Sikorski, Christopher; Keller, Emanuela

    2017-08-03

    To assess whether circadian patterns of temperature correlate with further values of intracranial pressure (ICP) in severe brain injury treated with hypothermia. We retrospectively analyzed temperature values in subarachnoid hemorrhage patients treated with hypothermia by endovascular cooling. The circadian patterns of temperature were correlated with the mean ICP across the following day (ICP 24 ). We analyzed data from 17 days of monitoring of three subarachnoid hemorrhage patients that underwent aneurysm coiling, sedation and hypothermia due to refractory intracranial hypertension and/or cerebral vasospasm. ICP 24 ranged from 11.5 ± 3.1 to 24.2 ± 6.2 mmHg. The ratio between the coefficient of variation of temperature during the nocturnal period (18:00-6:00) and the preceding diurnal period (6:00-18:00) [temperature variability (TV)] ranged from 0.274 to 1.97. Regression analysis showed that TV correlated with ICP 24 (Pearson correlation = -0.861, adjusted R square = 0.725, p TV) mmHg or, for 80% prediction interval, [Formula: see text] mmHg. The results indicate that the occurrence of ICP 24 higher than 20 mmHg is unlikely after a day with TV ≥1.0. TV correlates with further ICP during hypothermia regardless the strict range that temperature is maintained. Further studies with larger series could clarify whether intracranial hypertension in severe brain injury can be predicted by analysis of oscillation patterns of autonomic parameters across a period of 24 h or its harmonics.

  6. A quantitative index of intracranial cerebrospinal fluid distribution in normal pressure hydrocephalus using an MRI-based processing technique.

    Science.gov (United States)

    Tsunoda, A; Mitsuoka, H; Sato, K; Kanayama, S

    2000-06-01

    Our purpose was to quantify the intracranial cerebrospinal fluid (CSF) volume components using an original MRI-based segmentation technique and to investigate whether a CSF volume index is useful for diagnosis of normal pressure hydrocephalus (NPH). We studied 59 subjects: 16 patients with NPH, 14 young and 13 elderly normal volunteers, and 16 patients with cerebrovascular disease. Images were acquired on a 1.5-T system, using a 3D-fast asymmetrical spin-echo (FASE) method. A region-growing method (RGM) was used to extract the CSF spaces from the FASE images. Ventricular volume (VV) and intracranial CSF volume (ICV) were measured, and a VV/ICV ratio was calculated. Mean VV and VV/ICV ratio were higher in the NPH group than in the other groups, and the differences were statistically significant, whereas the mean ICV value in the NPH group was not significantly increased. Of the 16 patients in the NPH group, 13 had VV/ICV ratios above 30%. In contrast, no subject in the other groups had a VV/ICV ratios higher than 30%. We conclude that these CSF volume parameters, especially the VV/ICV ratio, are useful for the diagnosis of NPH.

  7. A quantitative index of intracranial cerebrospinal fluid distribution in normal pressure hydrocephalus using an MRI-based processing technique

    International Nuclear Information System (INIS)

    Tsunoda, A.; Mitsuoka, H.; Sato, K.; Kanayama, S.

    2000-01-01

    Our purpose was to quantify the intracranial cerebrospinal fluid (CSF) volume components using an original MRI-based segmentation technique and to investigate whether a CSF volume index is useful for diagnosis of normal pressure hydrocephalus (NPH). We studied 59 subjects: 16 patients with NPH, 14 young and 13 elderly normal volunteers, and 16 patients with cerebrovascular disease. Images were acquired on a 1.5-T system, using a 3D-fast asymmetrical spin- echo (FASE) method. A region-growing method (RGM) was used to extract the CSF spaces from the FASE images. Ventricular volume (VV) and intracranial CSF volume (ICV) were measured, and a VV/ICV ratio was calculated. Mean VV and VV/ICV ratio were higher in the NPH group than in the other groups, and the differences were statistically significant, whereas the mean ICV value in the NPH group was not significantly increased. Of the 16 patients in the NPH group, 13 had VV/ICV ratios above 30%. In contrast, no subject in the other groups had a VV/ICV ratios higher than 30%. We conclude that these CSF volume parameters, especially the VV/ICV ratio, are useful for the diagnosis of NPH. (orig.)

  8. A quantitative index of intracranial cerebrospinal fluid distribution in normal pressure hydrocephalus using an MRI-based processing technique

    Energy Technology Data Exchange (ETDEWEB)

    Tsunoda, A. [Department of Neurosurgery, Koshigaya Municipal Hospital, 10-47-1 Higashikoshigaya, Koshigaya City, Saitama 343-0023 (Japan); Mitsuoka, H.; Sato, K. [Department of Neurosurgery, Juntendo University (Japan); Kanayama, S. [Research and Development Centre, Toshiba Corporation (Japan)

    2000-06-01

    Our purpose was to quantify the intracranial cerebrospinal fluid (CSF) volume components using an original MRI-based segmentation technique and to investigate whether a CSF volume index is useful for diagnosis of normal pressure hydrocephalus (NPH). We studied 59 subjects: 16 patients with NPH, 14 young and 13 elderly normal volunteers, and 16 patients with cerebrovascular disease. Images were acquired on a 1.5-T system, using a 3D-fast asymmetrical spin- echo (FASE) method. A region-growing method (RGM) was used to extract the CSF spaces from the FASE images. Ventricular volume (VV) and intracranial CSF volume (ICV) were measured, and a VV/ICV ratio was calculated. Mean VV and VV/ICV ratio were higher in the NPH group than in the other groups, and the differences were statistically significant, whereas the mean ICV value in the NPH group was not significantly increased. Of the 16 patients in the NPH group, 13 had VV/ICV ratios above 30%. In contrast, no subject in the other groups had a VV/ICV ratios higher than 30%. We conclude that these CSF volume parameters, especially the VV/ICV ratio, are useful for the diagnosis of NPH. (orig.)

  9. Creep of Posidonia Shale at Elevated Pressure and Temperature

    Science.gov (United States)

    Rybacki, E.; Herrmann, J.; Wirth, R.; Dresen, G.

    2017-12-01

    The economic production of gas and oil from shales requires repeated hydraulic fracturing operations to stimulate these tight reservoir rocks. Besides simple depletion, the often observed decay of production rate with time may arise from creep-induced fracture closure. We examined experimentally the creep behavior of an immature carbonate-rich Posidonia shale, subjected to constant stress conditions at temperatures between 50 and 200 °C and confining pressures of 50-200 MPa, simulating elevated in situ depth conditions. Samples showed transient creep in the semibrittle regime with high deformation rates at high differential stress, high temperature and low confinement. Strain was mainly accommodated by deformation of the weak organic matter and phyllosilicates and by pore space reduction. The primary decelerating creep phase observed at relatively low stress can be described by an empirical power law relation between strain and time, where the fitted parameters vary with temperature, pressure and stress. Our results suggest that healing of hydraulic fractures at low stresses by creep-induced proppant embedment is unlikely within a creep period of several years. At higher differential stress, as may be expected in situ at contact areas due to stress concentrations, the shale showed secondary creep, followed by tertiary creep until failure. In this regime, microcrack propagation and coalescence may be assisted by stress corrosion. Secondary creep rates were also described by a power law, predicting faster fracture closure rates than for primary creep, likely contributing to production rate decline. Comparison of our data with published primary creep data on other shales suggests that the long-term creep behavior of shales can be correlated with their brittleness estimated from composition. Low creep strain is supported by a high fraction of strong minerals that can build up a load-bearing framework.

  10. Dust acoustic waves in complex plasmas at elevated pressure

    International Nuclear Information System (INIS)

    Filippov, A.V.; Starostin, A.N.; Tkachenko, I.M.; Fortov, V.E.

    2011-01-01

    The bi-Yukawa effective interaction potential with different screening constants is employed to calculate dust static correlation functions in the hyper-netted chain approximation and to generalize the theory of dust acoustic waves within the non-perturbative moment approach complemented by hydrodynamic considerations. For the bi-Yukawa interaction potential the sound speed becomes significantly wavenumber-dependent, an additional soft diffusion-like mode is predicted, and the static dielectric function is shown to take negative values. The results can be applied to non-equilibrium dusty plasmas at elevated pressure. -- Highlights: ► Bi-Yukawa interaction potential of dust particles with different screening lengths. ► Dust static correlation functions in the hyper-netted chain approximation. ► The moment and hydrodynamic approaches are in a good agreement at weak non-ideality. ► The dust acoustic wave phase and group velocities depend on the wavenumber. ► The moment approach hints the appearance of the diffusion-like soft mode.

  11. Post Traumatic Cerebral Oedema in Severe Head Injury is Related to Intracranial Pressure and Cerebral Perfusion Pressure but not to Cerebral Compliance

    Directory of Open Access Journals (Sweden)

    U Nujaimin

    2009-07-01

    Full Text Available This was a prospective cohort study, carried out in the Neuro Intensive Care Unit, Department of Neurosciences, Hospital Universiti Sains Malaysia, Kubang Kerian Kelantan. The study was approved by the local ethics committee and was conducted between November 2005 and September 2007 with a total of 30 patients included in the study. In our study, univariate analysis showed a statistically significant relationship between mean intracranial pressure (ICP as well as cerebral perfusion pressure (CPP with both states of basal cistern and the degree of diffuse injury and oedema based on the Marshall classification system. The ICP was higher while CPP and compliance were lower whenever the basal cisterns were effaced in cases of cerebral oedema with Marshall III and IV. In comparison, the study revealed lower ICP, higher mean CPP and better mean cerebral compliance if the basal cisterns were opened or the post operative CT brain scan showed Marshall I and II. These findings suggested the surgical evacuation of clots to reduce the mass volume and restoration of brain anatomy may reduce vascular engorgement and cerebral oedema, therefore preventing intracranial hypertension, and improving cerebral perfusion pressure and cerebral compliance. Nevertheless the study did not find any significant relationship between midline shifts and mean ICP, CPP or cerebral compliance even though lower ICP, higher CPP and compliance were frequently observed when the midline shift was less than 0.5 cm. As the majority of our patients had multiple and diffuse brain injuries, the absence of midline shift did not necessarily mean lower ICP as the pathology was bilateral and even when after excluding the multiple lesions, the result remained insignificant. We assumed that the CT brain scan obtained after evacuation of the mass lesion to assess the state basal cistern and classify the diffuse oedema may prognosticate the intracranial pressure and cerebral perfusion pressure

  12. Equal contribution of increased intracranial pressure and subarachnoid blood to cerebral blood flow reduction and receptor upregulation after subarachnoid hemorrhage. Laboratory investigation

    DEFF Research Database (Denmark)

    Ansar, Saema; Edvinsson, Lars

    2009-01-01

    OBJECT: Cerebral ischemia remains the key cause of disability and death in the late phase after subarachnoid hemorrhage (SAH), and its pathogenesis is still poorly understood. The purpose of this study was to examine whether the change in intracranial pressure or the extravasated blood causes the...

  13. Fifty shades of gradients: does the pressure gradient in venous sinus stenting for idiopathic intracranial hypertension matter? A systematic review.

    Science.gov (United States)

    McDougall, Cameron M; Ban, Vin Shen; Beecher, Jeffrey; Pride, Lee; Welch, Babu G

    2018-03-02

    OBJECTIVE The role of venous sinus stenting (VSS) for idiopathic intracranial hypertension (IIH) is not well understood. The aim of this systematic review is to attempt to identify subsets of patients with IIH who will benefit from VSS based on the pressure gradients of their venous sinus stenosis. METHODS MEDLINE/PubMed was searched for studies reporting venous pressure gradients across the stenotic segment of the venous sinus, pre- and post-stent pressure gradients, and clinical outcomes after VSS. Findings are reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS From 32 eligible studies, a total of 186 patients were included in the analysis. Patients who had favorable outcomes had higher mean pressure gradients (22.8 ± 11.5 mm Hg vs 17.4 ± 8.0 mm Hg, p = 0.033) and higher changes in pressure gradients after stent placement (19.4 ± 10.0 mm Hg vs 12.0 ± 6.0 mm Hg, p = 0.006) compared with those with unfavorable outcomes. The post-stent pressure gradients between the 2 groups were not significantly different (2.8 ± 4.0 mm Hg vs 2.7 ± 2.0 mm Hg, p = 0.934). In a multivariate stepwise logistic regression controlling for age, sex, body mass index, CSF opening pressure, pre-stent pressure gradient, and post-stent pressure gradient, the change in pressure gradient with stent placement was found to be an independent predictor of favorable outcome (p = 0.028). Using a pressure gradient of 21 as a cutoff, 81/86 (94.2%) of patients with a gradient > 21 achieved favorable outcomes, compared with 82/100 (82.0%) of patients with a gradient ≤ 21 (p = 0.022). CONCLUSIONS There appears to be a relationship between the pressure gradient of venous sinus stenosis and the success of VSS in IIH. A randomized controlled trial would help elucidate this relationship and potentially guide patient selection.

  14. Analysis of multi-factors affecting symptomatic intracranial hemorrhage in intraarterial thrombolysis with urokinase for acute ischemic stroke

    International Nuclear Information System (INIS)

    Qiao Qianlin; Zhou Shi; Wang Xuejian; Wu Qinghua; Song Jie

    2005-01-01

    Objective: To explore the causes and preventive measures of symptomatic intracranial hemorrhage in 217 patients with acute cerebral ischemic stroke treated with local intra-arterial urokinase. Methods: From February 1999 to June 2004, 217 patients were treated for acute ischemic stroke with local intra-arterial urokinase in our hospital. Factors associated with symptomatic intracranial hemorrhage of intra-arterial thrombolysis were analyzed by Stepwise logistic regression to identify some factors relating the prediction symptomatic intracranial hemorrhage. Results: Symptomatic intracranial hemorrhage occurred in 8 cases (3.7%). Predictors of the symptomatic intracranial hemorrhage were the elevated systolic blood pressure before therapy (odds ratio, 1.096; 95% CI, 1.006 to 1.194) and urokinase (UK) treatment (odds ratio, 1.068 ; 95% CL, 1.053 to 1.247). Risk of secondary symptomatic intracranial hemorrhage was increased with elevated systolic blood pressure. Other factors like age, initial treating time, NIHSS, diabetes and collateral circulation did not predict the symptomatic intracranial hemorrhage respectively. Conclusions: Predictors of symptomatic intracranial hemorrhage after local intra-arterial infusion of urokinase for acute ischemic stroke were the elevated systolic blood pressure before therapy and urokinase (UK) treatment. (authors)

  15. Investigating Soot Morphology in Counterflow Flames at Elevated Pressures

    KAUST Repository

    Amin, Hafiz Muhammad Fahid

    2018-01-01

    Practical combustion devices such as gas turbines and diesel engines operate at high pressures to increase their efficiency. Pressure significantly increases the overall soot yield. Morphology of these ultra-fine particles determines their airborne

  16. An evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury.

    Science.gov (United States)

    Vender, John; Waller, Jennifer; Dhandapani, Krishnan; McDonnell, Dennis

    2011-08-01

    Intracranial pressure measurements have become one of the mainstays of traumatic brain injury management. Various technologies exist to monitor intracranial pressure from a variety of locations. Transducers are usually placed to assess pressure in the brain parenchyma and the intra-ventricular fluid, which are the two most widely accepted compartmental monitoring sites. The individual reliability and inter-reliability of these devices with and without cerebrospinal fluid diversion is not clear. The predictive capability of monitors in both of these sites to local, regional, and global changes also needs further clarification. The technique of monitoring intraventricular pressure with a fluid-coupled transducer system is also reviewed. There has been little investigation into the relationship among pressure measurements obtained from these two sources using these three techniques. Eleven consecutive patients with severe, closed traumatic brain injury not requiring intracranial mass lesion evacuation were admitted into this prospective study. Each patient underwent placement of a parenchymal and intraventricular pressure monitor. The ventricular catheter tubing was also connected to a sensor for fluid-coupled measurement. Pressure from all three sources was measured hourly with and without ventricular drainage. Statistically significant correlation within each monitoring site was seen. No monitoring location was more predictive of global pressure changes or more responsive to pressure changes related to patient stimulation. However, the intraventricular pressure measurements were not reliable in the presence of cerebrospinal fluid drainage whereas the parenchymal measurements remained unaffected. Intraparenchymal pressure monitoring provides equivalent, statistically similar pressure measurements when compared to intraventricular monitors in all care and clinical settings. This is particularly valuable when uninterrupted cerebrospinal fluid drainage is desirable.

  17. Breakdown pressures and characteristic flaw sizes during fluid injection experiments in shale at elevated confining pressures.

    Science.gov (United States)

    Chandler, M.; Mecklenburgh, J.; Rutter, E. H.; Taylor, R.; Fauchille, A. L.; Ma, L.; Lee, P. D.

    2017-12-01

    Fracture propagation trajectories in gas-bearing shales depend on the interaction between the anisotropic mechanical properties of the shale and the anisotropic in-situ stress field. However, there is a general paucity of available experimental data on their anisotropic mechanical, physical and fluid-flow properties, especially at elevated confining pressures. A suite of mechanical, flow and elastic measurements have been made on two shale materials, the Whitby mudrock and the Mancos shale (an interbedded silt and mudstone), as well as Pennant sandstone, an isotropic baseline and tight-gas sandstone analogue. Mechanical characterization includes standard triaxial experiments, pressure-dependent permeability, brazilian disk tensile strength, and fracture toughness determined using double-torsion experiments. Elastic characterisation was performed through ultrasonic velocities determined using a cross-correlation method. Additionally, we report the results of laboratory-scale fluid injection experiments for the same materials. Injection experiments involved the pressurisation of a blind-ending central hole in a dry cylindrical sample. Pressurisation is conducted under constant volume-rate control, using silicon oils of varying viscosities. Breakdown pressure is not seen to exhibit a strong dependence on rock type or orientation, and increases linearly with confining pressure. In most experiments, a small drop in the injection pressure record is observed at what is taken to be fracture initiation, and in the Pennant sandstone this is accompanied by a small burst of acoustic energy. The shale materials were acoustically quiet. Breakdown is found to be rapid and uncontrollable after initiation if injection is continued. A simplified 2-dimensional model for explaining this is presented in terms of the stress intensities at the tip of a pressurised crack, and is used alongside the triaxial data to derive a characteristic flaw size from which the fractures have initiated

  18. Complications corner: Anterior thoracic disc surgery with dural tear/CSF fistula and low-pressure pleural drain led to severe intracranial hypotension.

    Science.gov (United States)

    Oudeman, Eline A; Nandoe Tewarie, Rishi D S; Jöbsis, G Joost; Arts, Mark P; Kruyt, Nyika D

    2015-01-01

    Thoracic disc surgery can lead to a life-threatening complication: intracranial hypotension due to a subarachnoid-pleural fistula. We report a 63-year-old male with paraparesis due to multiple herniated thoracic discs, with compressive myelopathy. The patient required a circumferential procedure including a laminectomy/fusion followed by an anterior thoracic decompression to address both diffuse idiopathic skeletal hyperostosis (DISH) anteriorly and posterior stenosis. The postoperative course was complicated by severe intracranial hypotension attributed to the erroneous placement of a low-pressure drain placed in the pleural cavity instead of a lumbar drain; this resulted in subdural hematoma's necessitating subsequent surgery. Severe neurological deterioration occurring after thoracic decompressive surgery may rarely be attributed to intracranial hypotension due to a subarachnoid-pleural fistula. Patients should be treated with external lumbar drainage of cerebrospinal fluid for 3-5 days rather than a low-pressure pleural drain to avoid the onset of intracranial hypotension leading to symptomatic subdural hematomas.

  19. Intracranial pressure monitoring in pediatric and adult patients with hydrocephalus and tentative shunt failure: a single-center experience over 10 years in 146 patients.

    Science.gov (United States)

    Sæhle, Terje; Eide, Per Kristian

    2015-05-01

    OBJECT In patients with hydrocephalus and shunts, lasting symptoms such as headache and dizziness may be indicative of shunt failure, which may necessitate shunt revision. In cases of doubt, the authors monitor intracranial pressure (ICP) to determine the presence of over- or underdrainage of CSF to tailor management. In this study, the authors reviewed their experience of ICP monitoring in shunt failure. The aims of the study were to identify the complications and impact of ICP monitoring, as well as to determine the mean ICP and characteristics of the cardiac-induced ICP waves in pediatric versus adult over- and underdrainage. METHODS The study population included all pediatric and adult patients with hydrocephalus and shunts undergoing diagnostic ICP monitoring for tentative shunt failure during the 10-year period from 2002 to 2011. The patients were allocated into 3 groups depending on how they were managed following ICP monitoring: no drainage failure, overdrainage, or underdrainage. While patients with no drainage failure were managed conservatively without further actions, over- or underdrainage cases were managed with shunt revision or shunt valve adjustment. The ICP and ICP wave scores were determined from the continuous ICP waveforms. RESULTS The study population included 71 pediatric and 75 adult patients. There were no major complications related to ICP monitoring, but 1 patient was treated for a postoperative superficial wound infection and another experienced a minor bleed at the tip of the ICP sensor. Following ICP monitoring, shunt revision was performed in 74 (51%) of 146 patients, while valve adjustment was conducted in 17 (12%) and conservative measures without any actions in 55 (38%). Overdrainage was characterized by a higher percentage of episodes with negative mean ICP less than -5 to -10 mm Hg. The ICP wave scores, in particular the mean ICP wave amplitude (MWA), best differentiated underdrainage. Neither mean ICP nor MWA levels showed any

  20. Development of a real-time monitoring system for intra-fractional motion in intracranial treatment using pressure sensors.

    Science.gov (United States)

    Inata, Hiroki; Araki, Fujio; Kuribayashi, Yuta; Hamamoto, Yasushi; Nakayama, Shigeki; Sodeoka, Noritaka; Kiriyama, Tetsukazu; Nishizaki, Osamu

    2015-09-21

    This study developed a dedicated real-time monitoring system to detect intra-fractional head motion in intracranial radiotherapy using pressure sensors. The dedicated real-time monitoring system consists of pressure sensors with a thickness of 0.6 mm and a radius of 9.1 mm, a thermoplastic mask, a vacuum pillow, and a baseplate. The four sensors were positioned at superior-inferior and right-left sides under the occipital area. The sampling rate of pressure sensors was set to 5 Hz. First, we confirmed that the relationship between the force and the displacement of the vacuum pillow follows Hook's law. Next, the spring constant for the vacuum pillow was determined from the relationship between the force given to the vacuum pillow and the displacement of the head, detected by Cyberknife target locating system (TLS) acquisitions in clinical application. Finally, the accuracy of our system was evaluated by using the 2  ×  2 confusion matrix. The regression lines between the force, y, and the displacement, x, of the vacuum pillow were given by y = 3.8x, y = 4.4x, and y = 5.0x when the degree of inner pressure was  -12 kPa,-20 kPa, and  -27 kPa, respectively. The spring constant of the vacuum pillow was 1.6 N mm(-1) from the 6D positioning data of a total of 2999 TLS acquisitions in 19 patients. Head motions of 1 mm, 1.5 mm, and 2 mm were detected in real-time with the accuracies of 67%, 84%, and 89%, respectively. Our system can detect displacement of the head continuously during every interval of TLS with a resolution of 1-2 mm without any radiation exposure.

  1. Increased intracranial pressure in a case of spinal cervical glioblastoma multiforme: analysis of these two rare conditions

    Directory of Open Access Journals (Sweden)

    C.M. de Castro-Costa

    1994-03-01

    Full Text Available The authors describe a rare case of increased intracranial hypertension consequent to a spinal cervical glioblastoma multiforme in a young patient. They analyse the physiopathology of intracranial hypertension in spinal tumors and the rarity of such kind of tumor in this location, and its clinico-pathological aspects.

  2. Investigations of Sooting Laminar Coflow Diffusion Flames at Elevated Pressures

    KAUST Repository

    Steinmetz, Scott

    2016-01-01

    diameters are successfully measured in nitrogen-diluted ethylene-air laminar coflow flames at pressures of 4, 8, 12, and 16 atm. An increase in particle size with pressure is found up to 12 atm, where particle sizes plateau. Particle size in the annulus

  3. Low-pressure balloon angioplasty with adjuvant pharmacological therapy in patients with acute ischemic stroke caused by intracranial arterial occlusions

    International Nuclear Information System (INIS)

    Nogueira, Raul G.; Schwamm, Lee H.; Buonanno, Ferdinando S.; Koroshetz, Walter J.; Yoo, Albert J.; Rabinov, James D.; Pryor, Johnny C.; Hirsch, Joshua A.

    2008-01-01

    The use of coronary balloons in the cerebral vasculature is limited due to their poor trackability and increased risk of vessel injury. We report our experience using more compliant elastomer balloons for thrombus resistant to intraarterial (IA) pharmacological and mechanical thrombolysis in acute stroke. We retrospectively analyzed 12 consecutive patients with an occluded intracranial artery treated with angioplasty using a low-pressure elastomer balloon. Angiograms were graded according to the Thrombolysis in Cerebral Infarction (TICI) and Qureshi grading systems. Outcomes were categorized as independent (modified Rankin scale, mRS, score ≤2), dependent (mRS score 3-5), or dead (mRS score 6). Included in the study were 12 patients (mean age 66±17 years, range 31-88 years; mean baseline National Institutes of Health stroke scale score 17±3, range 12-23). The occlusion sites were: internal carotid artery (ICA) terminus (five patients, including two concomitant cervical ICA occlusions), M1 segment (two patients), and basilar artery (two patients). Pharmacological treatment included intravenous (IV) t-PA only (two patients), IA urokinase only (nine patients), both IV t-PA and IA urokinase (one patient), and IV and/or IA eptifibatide (eight patients). Mean time to treatment was 5.9±3.9 h (anterior circulation) and 11.0±7.2 h (posterior circulation). Overall recanalization rate (TICI grade 2/3) was 91.6%. Procedure-related morbidity occurred in one patient (distal posterior inferior cerebellar artery embolus). There were no symptomatic hemorrhages. Outcomes at 90 days were independent (five patients), dependent (three patients) and dead (four patients, all due to progression of stroke with withdrawal of care). Angioplasty of acutely occluded intracranial arteries with low-pressure elastomer balloons results in high recanalization rates with an acceptable degree of safety. Prior use of thrombolytics may increase the chances of recanalization, and glycoprotein IIb

  4. A pitfall in the measurement of arterial blood pressure in the ischaemic limb during elevation

    DEFF Research Database (Denmark)

    Bülow, J; Jelnes, Rolf

    1987-01-01

    In order to evaluate if elevation of the ischaemic limb above heart level is an alternative to the conventionally applied method with external counterpressure for estimation of skin perfusion pressure, femoral and popliteal artery pressures were measured directly in eight patients with occlusion...... of the superficial femoral artery. The measurements were done in the horizontal position and during elevation of the calf above heart level. During elevation relative blood flow, measured by arterio-venous oxygen saturation differences, decreased compared with the horizontal position. In contrast the popliteal...... arterial pressure decreased only by 20% of the value expected from the degree of elevation of the calf above the level of the heart. Thus, it could be calculated that calf vascular resistance increased two- to three-fold on average during elevation. Four patients were reexamined with the venous pressure...

  5. IDIOPATHIC INTRACRANIAL HYPERTENSION IN A WOMAN WITH SCHIZOPHRENIA

    Directory of Open Access Journals (Sweden)

    Ivan N. Dimitrov

    2012-02-01

    Full Text Available Idiopathic intracranial hypertension (IIH or benign intracranial hypertension is a neurological syndrome characterized by elevated intracranial pressure. This uncommon disorder occurs primarily in obese women aged 10 to 50 years, sometimes in association with endocrine and metabolic dysfunction, with systemic diseases or when treated with multiple medications. We describe a case of IIH in a 43-year-old woman with schizophrenia treated with risperidone, demonstrating a typical clinical picture of benign intracranial hypertension. For the 5 years of treatment with risperidone she put on 35 kg in total (BMI> 35; for the last 2-3 months she began to complain of visual obscurations, nausea with vomiting. Ophthalmoscopy revealed bilateral asymmetric papilledema (OD>OS. Magnetic resonance imaging was normal, intracranial pressure was elevated IIH was diagnosed. Risperidone was discontinued and replaced with Seroquel 200 mg daily. Treatment with furosemide and mannitol 10 % was initiated. Papilledema resolved completely over the next 2 months. The patient was followed-up for four years after risperidone withdrawal. Weight loss of 28 kg was noted for four years. There were no relapses of headache, nausea, visual obscuration. Ophthalmologic examination revealed no papilledema.We suggest that prolonged use of antipsychotics, such as risperidone, should require proper surveillance for possible development of IIH and routine ophthalmologic examinations should be performed.

  6. A novel method for long-term monitoring of intracranial pressure in rats

    DEFF Research Database (Denmark)

    Uldall, Maria; Juhler, Marianne; Skjolding, Anders Daehli

    2014-01-01

    and in the epidural space. The two pressures were recorded twice a week for 59 days and the correlation was studied. RESULTS: The two pressure recordings correlated exceptionally well and the R(2) values on each recording day ranged between 0.99 and 1.00. However, the ventricular probes caused a number...... of complications including loss of patency and tissue damage probably due to cerebral infection, whereas the epidural probes were safe and reliable throughout the entire study. COMPARISON WITH EXISTING METHODS: Epidural probes are much easier to implant than ventricular probes. In addition, these new probes...

  7. The conundrum of arterial stiffness, elevated blood pressure, and aging.

    Science.gov (United States)

    AlGhatrif, Majd; Lakatta, Edward G

    2015-02-01

    Isolated systolic hypertension is a major health burden that is expanding with the aging of our population. There is evidence that central arterial stiffness contributes to the rise in systolic blood pressure (SBP); at the same time, central arterial stiffening is accelerated in patients with increased SBP. This bidirectional relationship created a controversy in the field on whether arterial stiffness leads to hypertension or vice versa. Given the profound interdependency of arterial stiffness and blood pressure, this question seems intrinsically challenging, or probably naïve. The aorta's function of dampening the pulsatile flow generated by the left ventricle is optimal within a physiological range of distending pressure that secures the required distal flow, keeps the aorta in an optimal mechanical conformation, and minimizes cardiac work. This homeostasis is disturbed by age-associated, minute alterations in aortic hemodynamic and mechanical properties that induce short- and long-term alterations in each other. Hence, it is impossible to detect an "initial insult" at an epidemiological level. Earlier manifestations of these alterations are observed in young adulthood with a sharp decline in aortic strain and distensibility accompanied by an increase in diastolic blood pressure. Subsequently, aortic mechanical reserve is exhausted, and aortic remodeling with wall stiffening and dilatation ensue. These two phenomena affect pulse pressure in opposite directions and different magnitudes. With early remodeling, there is an increase in pulse pressure, due to the dominance of arterial wall stiffness, which in turn accelerates aortic wall stiffness and dilation. With advanced remodeling, which appears to be greater in men, the effect of diameter becomes more pronounced and partially offsets the effect of wall stiffness leading to plateauing in pulse pressure in men and slower increase in pulse pressure (PP) than that of wall stiffness in women. The complex nature of

  8. Ultrasonographic Optic Nerve Sheath Diameter as a Surrogate Measure of Raised Intracranial Pressure in Severe Pregnancy-induced Hypertension Patients.

    Science.gov (United States)

    Singh, Shiv Kumar; Bhatia, Kiran

    2018-01-01

    It is a well-known fact that severe pregnancy-induced hypertension (PIH) can be disastrous at times as it can cause a lot of complications to both pregnant women and her baby. Hence, it is always desirable to know the extent of severity by a real-time and easily accessible modality like ultrasound. The aim of the study was to evaluate the incidence of raised intracranial pressure (ICP) in severe preeclampsia and eclampsia patients using ocular ultrasonography with optic nerve sheath diameter (ONSD) measurement. This study design was a prospective and clinically controlled blinded observational study. After taking necessary permissions from the Institution Ethical Committee, 75 patients were enrolled for the study. However, finally, 25 patients in severe preeclampsia and 24 in eclampsia group were compared with 25 normal term antenatal women. Demographic profiles, hemodynamic parameters, laboratory markers for severity of PIH, and ultrasonographic OSND were measured. They were statistically analyzed and compared using one-way ANOVA and Tukey's test. Value of P surrogate marker for raised ICP in severe PIH patients. It is a rapid, bedside, noninvasive, and readily accessible tool and could be a part of a holistic approach for managing such patients.

  9. Association of Inter-arm Blood Pressure Difference with Asymptomatic Intracranial and Extracranial Arterial Stenosis in Hypertension Patients.

    Science.gov (United States)

    Wang, Yan; Zhang, Jin; Qian, Yuesheng; Tang, Xiaofeng; Ling, Huawei; Chen, Kemin; Li, Yan; Gao, Pingjin; Zhu, Dingliang

    2016-07-14

    Inter-arm blood pressure (BP) difference has been associated with ischemic stroke. Local atherosclerosis of stroke differ among vulnerable individuals, whereas intracranial arterial stenosis (ICAS) is more frequently affected Asians, and extracranial arterial stenosis (ECAS) is more prevalent among whites. We hereby sought to explore the association of inter-arm BP difference with ICAS and ECAS in stroke-free hypertensive patients in Chinese population. All the 885 subjects were evaluated of ICAS and ECAS through computerized tomographic angiography. Both arm BP was measured simultaneously by Vascular Profiler-1000 device. In the continuous study, ICAS was significantly associated with age, male, average brachial SBP, diabetes, anti-hypertensive treatment and inter-arm DBP difference. ECAS was associated with age, inter-arm SBP and LDL. In the categorical study, subjects with the top quartile of inter-arm DBP difference (≥4 mmHg) showed significantly higher risk of ICAS (OR = 2.109; 95% CI, 1.24-3.587). And the participants with the top quartile of inter-arm SBP difference (≥6 mmHg) showed significantly higher risk of ECAS (OR = 2.288; 95% CI, 1.309-3.998). In conclusion, we reported a diverse association of inter-arm SBP/DBP difference with the ICAS/ECAS. Inter-arm DBP difference might be the early symbol of ICAS in Chinese population, which need further verification in long-term cohort study.

  10. Involvement of Smad3 pathway in atrial fibrosis induced by elevated hydrostatic pressure.

    Science.gov (United States)

    Wei, Wei; Rao, Fang; Liu, Fangzhou; Xue, Yumei; Deng, Chunyu; Wang, Zhaoyu; Zhu, Jiening; Yang, Hui; Li, Xin; Zhang, Mengzhen; Fu, Yongheng; Zhu, Wensi; Shan, Zhixin; Wu, Shulin

    2018-06-01

    Hypertension is a main risk factor for atrial fibrillation, but the direct effects of hydrostatic pressure on the atrial fibrosis are still unknown. The present study investigated whether hydrostatic pressure is responsible for atrial fibrosis, and addressed a potential role of the Smad pathway in this pathology. Biochemical assays were used to study regulation and expression of fibrotic factors in spontaneously hypertensive rats (SHRs) and Wistar rats, and in cardiac fibroblasts (CFs) cultured under standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure. Levels of atrial fibrosis and protein expression of fibrotic factors Col-1A1/-3A1, TGF-β1, and MMP-2 in SHRs' left atrial tissues were higher than those in Wistar rats. Exposure to elevated pressure was associated with the proliferation of CFs. The protein expression of Col-1A1/-3A1, TGF-β1, and MMP-2 in CFs was also up-regulated in a pressure-dependent manner. The proliferation of CFs and increased expressions of fibrotic markers induced by elevated hydrostatic pressure could be reversed by the Smad3 inhibitor naringenin. The activation of Smad3 pathway was also stimulated by elevated hydrostatic pressure. These results demonstrate that CF secretory function and proliferation can be up-regulated by exposure to elevated pressure, and that Smad3 may modulate CF activation induced by high hydrostatic pressure. © 2017 Wiley Periodicals, Inc.

  11. Laser ignition of liquid petroleum gas at elevated pressures

    Science.gov (United States)

    Loktionov, E.; Pasechnikov, N.; Telekh, V.

    2017-11-01

    Recent development of laser spark plugs for internal combustion engines have shown lack of data on laser ignition of fuel mixtures at multi-bar pressures needed for laser pulse energy and focusing optimisation. Methane and hydrogen based mixtures are comparatively well investigated, but propane and butane based ones (LPG), which are widely used in vehicles, are still almost unstudied. Optical breakdown thresholds in gases decrease with pressure increase up to ca. 100 bar, but breakdown is not a sufficient condition for combustion ignition. So minimum ignition energy (MIE) becomes more important for combustion core onset, and its dependency on mixture composition and pressure has several important features. For example, unlike breakdown threshold, is poorly dependent on laser pulse length, at least in pico- and to microsecond range. We have defined experimentally the dependencies of minimum picosecond laser pulse energies (MIE related value) needed for ignition of LPG based mixtures of 1.0 to 1.6 equivalence ratios and pressure of 1.0 to 3.5 bar. In addition to expected values decrease, low-energy flammability range broadening has been found at pressure increase. Laser ignition of LPG in Wankel rotary engine is reported for the first time.

  12. Comparative Autoignition Trends in Butanol Isomers at Elevated Pressure

    KAUST Repository

    Weber, Bryan W.

    2013-03-21

    Autoignition experiments of stoichiometric mixtures of s-, t-, and i-butanol in air have been performed using a heated rapid compression machine (RCM). At compressed pressures of 15 and 30 bar and for compressed temperatures in the range 715-910 K, no evidence of a negative temperature coefficient region in terms of ignition delay response is found. The present experimental results are also compared with previously reported RCM data of n-butanol in air. The order of reactivity of the butanols is n-butanol > s-butanol ≈ i-butanol > t-butanol at the lower pressure but changes to n-butanol > t-butanol > s-butanol > i-butanol at higher pressure. In addition, t-butanol shows preignition heat release behavior, which is especially evident at higher pressures. To help identify the controlling chemistry leading to this preignition heat release, off-stoichiometric experiments are further performed at 30 bar compressed pressure, for t-butanol at φ = 0.5 and φ = 2.0 in air. For these experiments, higher fuel loading (i.e., φ = 2.0) causes greater preignition heat release (as indicated by greater pressure rise) than the stoichiometric or φ = 0.5 cases. Comparison of the experimental ignition delays with the simulated results using two literature kinetic mechanisms shows generally good agreement, and one mechanism is further used to explore and compare the fuel decomposition pathways of butanol isomers. Using this mechanism, the importance of peroxy chemistry in the autoignition of the butanol isomers is highlighted and discussed. © 2013 American Chemical Society.

  13. Prevalence of obesity and elevated blood pressure among bankers ...

    African Journals Online (AJOL)

    The aim of this study was to determine the prevalence of obesity and hypertension among bankers in Lagos State, Nigeria. Methods: Blood pressure, body mass index (BMI) and waist circumference were measured in 260 professional bankers from 56 bank branches in Lagos. Results: The mean age of the respondents was ...

  14. Measurements and modeling of VLLE at elevated pressures

    DEFF Research Database (Denmark)

    Laursen, Torben

    and pure component calibration. Samples from the different liquid phases in the high-pressure cell is taken using a moveable needle. The systems investigated have been a combination of the components: CO2, N2, di-methyl ether (DME), water, methanol, ethanol and 1-propanol. 41 isotherms have been measured...

  15. Headache attributed to intracranial pressure alterations: applicability of the International Classification of Headache Disorders ICHD-3 beta version versus ICHD-2.

    Science.gov (United States)

    Curone, M; Peccarisi, C; Bussone, G

    2015-05-01

    The association between headache and changes in intracranial pressure is strong in clinical practice. Syndromes associated with abnormalities of cerebrospinal fluid (CSF) pressure include spontaneous intracranial hypotension (SIH) and idiopathic intracranial hypertension (IIH). In 2013, the Headache Classification Committee of the International Headache Society (IHS) published the third International Classification of Headache Disorders (ICHD-3 beta version). The aim of this study was to investigate applicability of the new ICHD-3 versus ICHD-2 criteria in a clinical sample of patients with intracranial pressure (ICP) alterations. Patients admitted at our Headache Center for headache evaluation in whom a diagnosis of ICP alterations was performed were reviewed. 71 consecutive patients were studied. 40 patients (Group A) were diagnosed as IIH, 22 (Group B) as SIH, 7 (Group C) and 2 (Group D), respectively, as symptomatic intracranial hypertension and symptomatic intracranial hypotension. Main headache features were: in Group A, daily or nearly-daily headache (100 %) with diffuse/non-pulsating pain (73 %), aggravated by coughing/straining (54 %) and migrainous-associated symptoms (43 %). In Group B, an orthostatic headache (100 %) with nausea (29 %), vomiting (24 %), hearing disturbance (33 %), neck pain (48 %), hypacusia (24 %), photophobia (22 %) was reported. In Group C, a diffuse non-pulsating headache was present in 95 % with vomiting (25 %), sixth nerve palsy (14 %) and tinnitus (29 %). In Group D, an orthostatic headache with neck stiffness was reported by 100 %. Regarding applicability of ICHD-2 criteria in Group A, 73 % of the patients fitted criterion A; 100 %, criterion B; 100 %, criterion C; and 75 %, criterion D; while applying ICHD-3 beta version criteria, 100 % fitted criterion A; 97.5 %, criterion B; 100 %, criterion C; and 100 %, criterion D. In Group B, application of ICHD-2 showed 91 % patients fitting criterion A; 100 %, criterion B; 100

  16. Elevated blood pressure among primary school children in Dar es salaam, Tanzania: prevalence and risk factors.

    Science.gov (United States)

    Muhihi, Alfa J; Njelekela, Marina A; Mpembeni, Rose N M; Muhihi, Bikolimana G; Anaeli, Amani; Chillo, Omary; Kubhoja, Sulende; Lujani, Benjamin; Maghembe, Mwanamkuu; Ngarashi, Davis

    2018-02-13

    Whilst the burden of non-communicable diseases is increasing in developing countries, little data is available on blood pressure among Tanzanian children. This study aimed at determining the blood pressure profiles and risk factors associated with elevated blood pressure among primary school children in Dar es Salaam, Tanzania. We conducted a cross sectional survey among 446 children aged 6-17 years from 9 randomly selected primary schools in Dar es Salaam. We measured blood pressure using a standardized digital blood pressure measuring machine (Omron Digital HEM-907, Tokyo, Japan). We used an average of the three blood pressure readings for analysis. Elevated blood pressure was defined as average systolic or diastolic blood pressure ≥ 90th percentile for age, gender and height. The proportion of children with elevated blood pressure was 15.2% (pre-hypertension 4.4% and hypertension 10.8%). No significant gender differences were observed in the prevalence of elevated BP. Increasing age and overweight/obese children were significantly associated with elevated BP (p = 0.0029 and p < 0.0001) respectively. Similar associations were observed for age and overweight/obesity with hypertension. (p = 0.0506 and p < 0.0001) respectively. In multivariate analysis, age above 10 years (adjusted RR = 3.63, 95% CI = 1.03-7.82) was significantly and independently associated with elevated BP in this population of school age children. We observed a higher proportion of elevated BP in this population of school age children. Older age and overweight/obesity were associated with elevated BP. Assessment of BP and BMI should be incorporated in school health program in Tanzania to identify those at risk so that appropriate interventions can be instituted before development of associated complications.

  17. Measurement of local void fraction at elevated temperature and pressure

    International Nuclear Information System (INIS)

    Duncan, D.; Trabold, T.A.

    1993-03-01

    Significant advances have recently been made in analytical and computational methods for the prediction of local thermal-hydraulic conditions in gas/liquid two-phase flows. There is, however, a need for extensive experimental data, for the dual purposes of constitutive relation development and code qualification. There is especially true of systems involving complicated geometries and/or extreme flow conditions for which little, if any, applicable information exists in the open literature. For the tests described in the present paper, a novel electrical probe has been applied to measure the void fraction in atmospheric pressure air/water flows, and steam/water mixtures at high temperature and pressure. The data acquired in the latter experiments are compared with the results of a one-dimensional two-fluid computational analysis

  18. Intraparenchymal intracranial pressure monitoring in patients with acute liver failure Monitoreo intraparenquimatoso de presión intracraneana en pacientes con falla hepática aguda

    Directory of Open Access Journals (Sweden)

    Alejandra T. Rabadán

    2008-06-01

    Full Text Available BACKGROUND: Elevated intracranial pressure (ICP is a common cause of death in acute liver failure (ALF and is determinant for decision-making regarding the timing of liver transplantation. The recommended type ICP monitoring device is controversial in ALF patients. Epidural devices had less risk of hemorrhagic complications, but they are less reliable than intraparenchymal ones. METHOD: Twenty-three patients with ALF were treated, and 19 of them received a liver transplant. Seventeen patients had ICP monitoring because of grade III-IV encephalopathy. All patients received fresh plasma (2-3 units before and during placing the intraparenchymal device. RESULTS: Eleven cases (64.7% had elevated ICP, and 6 patients (35.2% had normal values. One patient (5.9% had an asymptomatic small intraparenchymal haemorrhage ANTECEDENTES: La presión intracraneana elevada (PIC es una causa frecuente de muerte en la falla hepática aguda (FHA y es determinante para la toma de decisiones respecto del momento del transplante hepático. El tipo de dispositivo para el monitoreo de OIC es controversial em los pacientes em FHA. Los dispositivos epidurales tienen menos riesgo de complicaciones hemorrágicas, pero son menos confiables que los intraparenquimatosos. MÉTODO: Veintitrés pacientes con FHA fueron tratados, y 19 de ellos recibieron un transplante hepático. diecisiete pacientes tuvieron monitoreo de PIC debido a encefalopatía grado III-IV. Todos los pacientes recibieron plasma fresco (2-3 unidades antes y durante la colocación de la fibra intraparenquimatosa. RESULTADOS: Once casos (64.7% tuvieron PIC elevada, y 6 pacientes (35.2% tuvieron valores normales. Un paciente (5.9% tuvo una pequeña hemorragia intraparenquimatosa asintomática <1cm³ en TAC, la cual no impidió el transplante hepático. CONCLUSIÓN: En nuestra experiencia, el monitoreo intraparenquimatoso de presión intracraneana en pacientes con FHA parece ser un método preciso y con bajo riesgo

  19. Non-invasive estimation of intracranial pressure. MR-based evaluation in children with hydrocephalus; Nichtinvasive Bestimmung des intrakraniellen Drucks. MR-basierte Untersuchung bei Kindern mit Hydrozephalus

    Energy Technology Data Exchange (ETDEWEB)

    Muehlmann, M.; Steffinger, D.; Ertl-Wagner, B.; Koerte, I.K. [Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Klinische Radiologie, Muenchen (Germany); Peraud, A. [Ludwig-Maximilians-Universitaet Muenchen, Abteilung fuer Neurochirurgie, Muenchen (Germany); Lehner, M. [Dr. von Haunersches Kinderspital, Ludwig-Maximilians-Universitaet Muenchen, Abteilung fuer Kinderchirurgie, Muenchen (Germany); Heinen, F.; Alperin, N. [University Miami, Department of Radiology, Miller School of Medicine, Miami (United States)

    2012-09-15

    The intracranial pressure (ICP) is a crucially important parameter for diagnostic and therapeutic decision-making in patients with hydrocephalus. So far there is no standard method to non-invasively assess the ICP. Various approaches to obtain the ICP semi-invasively or non-invasively are discussed and the clinical application of a magnetic resonance imaging (MRI)-based method to estimate ICP (MR-ICP) is demonstrated in a group of pediatric patients with hydrocephalus. Arterial inflow, venous drainage and craniospinal cerebrospinal fluid (CSF) flow were quantified using phase-contrast imaging to derive the MR-ICP. A total of 15 patients with hydrocephalus (n=9 treated with shunt placement or ventriculostomy) underwent MRI on a 3 T scanner applying retrospectively-gated cine phase contrast sequences. Of the patients six had clinical symptoms indicating increased ICP (age 2.5-14.61 years, mean 7.4 years) and nine patients had no clinical signs of elevated ICP (age 2.1-15.9 years; mean 9.8 years; all treated with shunt or ventriculostomy). Median MR-ICP in symptomatic patients was 24.5 mmHg (25th percentile 20.4 mmHg; 75th percentile 44.6 mmHg). Median MR-ICP in patients without acute signs of increased ICP was 9.8 mmHg (25th percentile 8.6 mmHg; 75th percentile 11.4 mmHg). Group differences were significant (p < 0.001; Mann-Whitney U-test). The MR-ICP technique is a promising non-invasive tool for estimating ICP. Further studies in larger patient cohorts are warranted to investigate its application in children with hydrocephalus. (orig.) [German] Der intrakranielle Druck (''intracranial pressure'' - ICP) ist ein entscheidender Parameter bei der Diagnostik, Therapie und Verlaufsbeurteilung von Patienten mit Hydrozephalus. Derzeit gibt es keine radiologische Standardmethode, um den intrakraniellen Druck quantitativ zu bestimmen. Methoden zur invasiven und nichtinvasiven Einschaetzung des ICP werden diskutiert und die Anwendung eines MR

  20. Método para registro continuo da pressão intracraniana A method for continuous monitoring of the intracranial pressure

    Directory of Open Access Journals (Sweden)

    Henrique S. Ivamoto

    1975-06-01

    Full Text Available Pacientes com hipertensão intracraniana aguda podem ser melhor manipulados se a pressão intracraniana for constantemente medida. Uma série de 91 pacientes com traumatismos cranio-encefálicos agudos, hemorragia subaracnóidea, encefalite, hemorragia intracerebral, ou intoxicação por monóxido de carbono foi acompanhada usando o interruptor a pressão de Numoto por um método aqui descrito. O principal benefício tem sido o conhecimento do valor da pressão intracraniana a todo momento e a detecção rápida de elevações da pressão. Complicações se limitaram a 3 casos de infecção. Dois deles foram pequenas coleções purulentas no ponto de saída do tubo no couro cabeludo. Um paciente com uma fratura craniana exposta, laceração cerebral e hematoma intracerebral desenvolveu uma infecção da ferida operatoria e abscesso cerebral que requereu drenagem.Patients suffering acute intracranial pressure increases can be more advantageously handled if the intracranial pressure is constantly monitored. 91 patients with acute head injuries, hydrocephalus, cerebral infarction, subarachnoid hemorrhage, encephalitis, intracerebral hemorrhage, or carbon monoxide intoxication have been so monitored by using the Numoto pressure switch by a method herein described. The main advantage has been the knowledge of the level of intracranial pressure at any given time and the early detection of a rising pressure when this phenomenon occurred. There were no complications except for 3 cases of infection. Two of these cases were minor purulent collections only at the site of exit of the tube in the scalp. One patient with a compound wound, cerebral laceration, and intracerebral hematoma developed a wound infection and brain abscess which required drainage.

  1. Terson syndrome in aneurysmal subarachnoid hemorrhage-its relation to intracranial pressure, admission factors, and clinical outcome.

    Science.gov (United States)

    Joswig, Holger; Epprecht, Lorenz; Valmaggia, Christophe; Leschka, Sebastian; Hildebrandt, Gerhard; Fournier, Jean-Yves; Stienen, Martin Nikolaus

    2016-06-01

    A large number of reports have not been able to clarify the pathophysiology of Terson syndrome (TS) in aneurysmal subarachnoid hemorrhage (aSAH). Prospective single-center study on aSAH patients. Fundoscopic and radiological signs of TS were assessed. The opening intracranial pressure (ICP) in patients who required a ventriculostomy was recorded with a manometer. Six out of 36 included patients had TS (16.7 %), which was associated with unfavorable admission scores. Twenty-nine patients (80.5 %) required ventriculostomy; TS was associated with higher ICP (median, 40 vs. 15 cm cmH2O, p = .003); all patients with TS had pathological ICP values of >20 cmH2O. Patients with a ruptured aneurysm of the anterior cerebral artery complex were ten times as likely to suffer from TS (OR 10.0, 95 % CI 1.03-97.50). Detection of TS on CT had a sensitivity of 50 %, a specificity of 98.4 %, a positive predictive value of 83.3 %, and a negative predictive value of 92.4 %. Mortality was 45 times as high in patients with TS (OR 45.0, 95 % CI 3.86-524.7) and neurologic morbidity up until 3 months post-aSAH was significantly higher in patients with TS (mRS 4-6; 100 vs. 17 %; p = .001). Our findings demonstrate an association between raised ICP and the incidence of TS. TS should be ruled out in aSAH patients presenting comatose or with raised ICP to ensure upfront ophthalmological follow-up. In alert patients without visual complaints and a TS-negative CT scan, the likelihood for the presence of TS is very low.

  2. Hydrodynamics in a cocurrent gas-liquid trickle bed at elevated pressures

    NARCIS (Netherlands)

    Wammes, W.J.A.; Middelkamp, J.; Huisman, W.J.; Huisman, W.J.; de Baas, C.M.; de Baas, C.M.; Westerterp, K.R.

    1991-01-01

    Data on design and operation of trickle beds at elevated pressures are scarce. In this study the influence of the gas density on the liquid holdup, the pressure drop, and the transition between trickle and pulse flow has been investigated in a tricklebed reactor operating up to 7.5 MPa and with

  3. Using Smartphone Pressure Sensors to Measure Vertical Velocities of Elevators, Stairways, and Drones

    Science.gov (United States)

    Monteiro, Martín; Martí, Arturo C.

    2017-01-01

    We measure the vertical velocities of elevators, pedestrians climbing stairs, and drones (flying unmanned aerial vehicles), by means of smartphone pressure sensors. The barometric pressure obtained with the smartphone is related to the altitude of the device via the hydrostatic approximation. From the altitude values, vertical velocities are…

  4. Elevated temperature and high pressure large helium gas loop

    International Nuclear Information System (INIS)

    Sakasai, Minoru; Midoriyama, Shigeru; Miyata, Toyohiko; Nakase, Tsuyoshi; Izaki, Makoto

    1979-01-01

    The development of high temperature gas-cooled reactors especially aiming at the multi-purpose utilization of nuclear heat energy is carried out actively in Japan and West Germany. In Japan, the experimental HTGR of 50 MWt and 1000 deg C outlet temperature is being developed by Japan Atomic Energy Research Institute and others since 1969, and the development of direct iron-making technology utilizing high temperature reducing gas was started in 1973 as the large project of Ministry of Internalional Trade and Industry. Kawasaki Heavy Industries, Ltd., Has taken part in these development projects, and has developed many softwares for nuclear heat design, system design and safety design of nuclear reactor system and heat utilization system. In hardwares also, efforts have been exerted to develop the technologies of design and manufacture of high temperature machinery and equipments. The high temperature, high pressure, large helium gas loop is under construction in the technical research institute of the company, and it is expected to be completed in December, 1979. The tests planned are that of proving the dynamic performances of the loop and its machinery and equipments and the verification of analysis codes. The loop is composed of the main circulation system, the objects of testing, the helium gas purifying system, the helium supplying and evacuating system, instruments and others. (Kako, I.)

  5. Solubility of krypton in hydrofracture grout at elevated pressures

    International Nuclear Information System (INIS)

    Fitzgerald, C.L.; Mailen, J.C.

    1982-01-01

    The solubilities of krypton in water, simulated waste solution, and simulated grout at about 25 0 C and to pressures of 150 atm have been determined. The results of these studies show that preliminary calculations of krypton solubility based on the aqueous component of the hydrofracture grout were overly pessimistic. The volume of noble gas generated annually by the reference reprocessing plant would be soluble in the annual hydrofracture grout injection at ORNL at about 10 atm. The amount of krypton in the gas phase would depend on the amount of air in the hydrofracture grout mixture. At 34 atm, and with a small air volume relative to the injected krypton, the krypton would constitute about 30% of the gas bubbles. The disposal of krypton via injection with hydrofracture grout seems to be a viable process. The next logical steps would be to determine the krypton diffusion rate at injection conditions, and possibly to perform a test injection. At present, the schedule for future work is uncertain since funds for this project have been reduced significantly

  6. Selective loss of orientation column maps in visual cortex during brief elevation of intraocular pressure.

    Science.gov (United States)

    Chen, Xin; Sun, Chao; Huang, Luoxiu; Shou, Tiande

    2003-01-01

    To compare the orientation column maps elicited by different spatial frequency gratings in cortical area 17 of cats before and during brief elevation of intraocular pressure (IOP). IOP was elevated by injecting saline into the anterior chamber of a cat's eye through a syringe needle. The IOP was elevated enough to cause a retinal perfusion pressure (arterial pressure minus IOP) of approximately 30 mm Hg during a brief elevation of IOP. The visual stimulus gratings were varied in spatial frequency, whereas other parameters were kept constant. The orientation column maps of the cortical area 17 were monocularly elicited by drifting gratings of different spatial frequencies and revealed by a brain intrinsic signal optical imaging system. These maps were compared before and during short-term elevation of IOP. The response amplitude of the orientation maps in area 17 decreased during a brief elevation of IOP. This decrease was dependent on the retinal perfusion pressure but not on the absolute IOP. The location of the most visible maps was spatial-frequency dependent. The blurring or loss of the pattern of the orientation maps was most severe when high-spatial-frequency gratings were used and appeared most significantly on the posterior part of the exposed cortex while IOP was elevated. However, the basic patterns of the maps remained unchanged. Changes in cortical signal were not due to changes in the optics of the eye with elevation of IOP. A stable normal IOP is essential for maintaining normal visual cortical functions. During a brief and high elevation of IOP, the cortical processing of high-spatial-frequency visual information was diminished because of a selectively functional decline of the retinogeniculocortical X pathway by a mechanism of retinal circulation origin.

  7. Pressure buffering by the tympanic membrane. In vivo measurements of middle ear pressure fluctuations during elevator motion.

    Science.gov (United States)

    Padurariu, Simona; de Greef, Daniël; Jacobsen, Henrik; Nlandu Kamavuako, Ernest; Dirckx, Joris J; Gaihede, Michael

    2016-10-01

    The tympanic membrane (TM) represents a pressure buffer, which contributes to the overall pressure regulation of the middle ear (ME). This buffer capacity is based on its viscoelastic properties combined with those of the attached ossicular chain, muscles and ligaments. The current work presents a set of in vivo recordings of the ME pressure variations normally occurring in common life: elevator motion. This is defined as a situation of smooth ambient pressure increase or decrease on a limited range and at a low rate of pressure change. Based on these recordings, the purpose was a quantitative analysis of the TM buffer capacity including the TM compliance. The pressure changes in seven normal adult ME's with intact TM's were continuously recorded directly inside the ME cavity during four different elevator trips using a high precision instrument. The TM buffer capacity was determined by the ratio between the changes in ME and the ambient pressure. Further, the ME volumes were calculated by Boyle's Law from pressure recordings during inflation-deflation tests; subsequently the TM compliance could also be calculated. Finally, the correlation between the ME volume and buffer function was determined. Twenty-one elevator trips could be used for the analysis. The overall mean TM pressure buffering capacity was 23.3% (SEM = 3.4), whereas the mean overall compliance was 28.9 × 10 -3  μL/Pa (SEM = 4.8). A strong negative linear correlation was found between the TM buffer capacity and the ME volumes (R 2  = 0.92). These results were in fair agreement with the literature obtained in clinical as well as temporal bone experiments, and they provide an in vivo reference for the normal ME function as well as for ME modeling. The TM buffer capacity was found more efficient in smaller mastoids. Possible clinical implications are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Analysis and evaluation system for elevated temperature design of pressure vessels

    International Nuclear Information System (INIS)

    Hayakawa, Teiji; Sayawaki, Masaaki; Nishitani, Masahiro; Mii, Tatsuo; Murasawa, Kanji

    1977-01-01

    In pressure vessel technology, intensive efforts have recently been made to develop the elevated temperature design methods. Much of the impetus of these efforts has been provided mainly by the results of the Liquid Metal Fast Breeder Reactor (LMFBR) and more recently, of the High Temperature Gas-cooled Reactor (HTGR) Programs. The pressure vessels and associated components in these new type nuclear power plants must operate for long periods at elevated temperature where creep effects are significant and then must be designed by rigorous analysis for high reliability and safety. To carry out such an elevated temperature designing, numbers of highly developed analysis and evaluation techniques, which are so complicated as to be impossible by manual work, are indispensable. Under these circumstances, the authors have made the following approaches in the study: (1) Study into basic concepts and the associated techniques in elevated temperature design. (2) Systematization (Analysis System) of the procedure for loads and stress analyses. (3) Development of post-processor, ''POST-1592'', for strength evaluation based on ASME Code Case 1592-7. By linking the POST-1592 together with the Analysis System, an analysis and evaluation system is developed for an elevated temperature design of pressure vessels. Consequently, designing of elevated temperature vessels by detailed analysis and evaluation has easily and effectively become feasible by applying this software system. (auth.)

  9. The difference in endolymphatic hydrostatic pressure elevation induced by isoproterenol between the ampulla and the cochlea.

    Science.gov (United States)

    Inamoto, Ryuhei; Miyashita, Takenori; Matsubara, Ai; Hoshikawa, Hiroshi; Mori, Nozomu

    2017-06-01

    The purpose of the study was to investigate the difference in the responses of endolymphatic hydrostatic pressure to isoproterenol, β-adrenergic receptor agonist, between pars superior and pars inferior. The hydrostatic pressure of endolymph and perilymph and endolymphatic potential in the ampulla and the cochlea during the intravenous administration of isoproterenol were recorded using a servo-null system in guinea pigs. The hydrostatic pressure of endolymph and perilymph in the ampulla and cochlea was similar in magnitude. Isoproterenol significantly increased hydrostatic pressure of ampullar and cochlear endolymph and perilymph with no change in the ampullar endolymphatic potential and endocochlear potential, respectively. The isoproterenol-induced maximum change of endolymphatic hydrostatic pressure in ampulla was significantly (phydrostatic pressure in the ampulla disappeared like that in the cochlea. Isoproterenol elevates endolymphatic hydrostatic pressure in different manner between the vestibule and the cochlea. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Idiopathic intracranial hypertension: case report

    Directory of Open Access Journals (Sweden)

    Iacob G.

    2015-12-01

    Full Text Available Idiopathic intracranial hypertension - IIH (synonymous old terms: benign intracranial hypertension - BIH, pseudotumor-cerebri - PTC it’s a syndrome, related to elevated intracranial pressure, of unknown cause, sometimes cerebral emergency, occuring in all age groups, especially in children and young obese womans, in the absence of an underlying expansive intracranial lesion, despite extensive investigations. Although initial symptoms can resolve, IIH displays a high risk of recurrence several months or years later, even if initial symptoms resolved. Results: A 20-year-old male, obese since two years (body mass index 30, 9, was admitted for three months intense headache, vomiting, diplopia, progressive visual acuity loss. Neurologic examination confirmed diplopia by left abducens nerve palsy, papilledema right > left. At admission, cerebral CT scan and cerebral MRI with angio MRI 3DTOF and 2D venous TOF was normal. Despite treatment with acetazolamide (Diamox, corticosteroid, antidepressants (Amitriptyline, anticonvulsivants (Topiramate three weeks later headache, diplopia persist and vision become worse, confirmed by visual field assessment, visual evoked potential (VEP. A cerebral arteriography demonstrate filling defect of the superior sagittal sinus in the 1/3 proximal part and very week filling of the transverse right sinus on venous time. Trombophylic profile has revealed a heterozygote V factor Leyden mutation, a homozygote MTHFR and PAI mutation justifying an anticoagulant treatment initiated to the patient. The MRI showed a superior sagittal sinus, right transverse and sigmoid sinus thrombosis, dilatation and buckling of the optic nerve sheaths with increased perineural fluid especially retrobulbar, discrete flattening of the posterior segment of the eyeballs, spinal MRI showed posterior epidural space with dilated venous branches, with mass effect on the spinal cord, that occurs pushed anterior on sagittal T1/T2 sequences cervical and

  11. Traffic congestion and blood pressure elevation: A comparative cross-sectional study in Lebanon.

    Science.gov (United States)

    Bou Samra, Patrick; El Tomb, Paul; Hosni, Mohammad; Kassem, Ahmad; Rizk, Robin; Shayya, Sami; Assaad, Sarah

    2017-12-01

    This comparative cross-sectional study examines the association between traffic congestion and elevation of systolic and/or diastolic blood pressure levels among a convenience sample of 310 drivers. Data collection took place during a gas station pause at a fixed time of day. Higher average systolic (142 vs 123 mm Hg) and diastolic (87 vs 78 mm Hg) blood pressures were detected among drivers exposed to traffic congestion compared with those who were not exposed (P<.001), while controlling for body mass index, age, sex, pack-year smoking, driving hours per week, and occupational driving. Moreover, among persons exposed to traffic congestion, longer exposure time was associated with higher systolic and diastolic blood pressures. Further studies are needed to better understand the mechanisms of the significant association between elevated blood pressure and traffic congestion. ©2017 Wiley Periodicals, Inc.

  12. Location of the internal carotid artery and ophthalmic artery segments for non-invasive intracranial pressure measurement by multi-depth TCD.

    Science.gov (United States)

    Hamarat, Yasin; Deimantavicius, Mantas; Kalvaitis, Evaldas; Siaudvytyte, Lina; Januleviciene, Ingrida; Zakelis, Rolandas; Bartusis, Laimonas

    2017-12-01

    The aim of the present study was to locate the ophthalmic artery by using the edge of the internal carotid artery (ICA) as the reference depth to perform a reliable non-invasive intracranial pressure measurement via a multi-depth transcranial Doppler device and to then determine the positions and angles of an ultrasonic transducer (UT) on the closed eyelid in the case of located segments. High tension glaucoma (HTG) patients and healthy volunteers (HVs) undergoing non-invasive intracranial pressure measurement were selected for this prospective study. The depth of the edge of the ICA was identified, followed by a selection of the depths of the IOA and EOA segments. The positions and angles of the UT on the closed eyelid were measured. The mean depth of the identified ICA edge for HTG patients was 64.3 mm and was 63.0 mm for HVs (p = 0.21). The mean depth of the selected IOA segment for HTG patients was 59.2 mm and 59.3 mm for HVs (p = 0.91). The mean depth of the selected EOA segment for HTG patients was 48.5 mm and 49.8 mm for HVs (p = 0.14). The difference in the located depths of the segments between groups was not statistically significant. The results showed a significant difference in the measured UT angles in the case of the identified edge of the ICA and selected ophthalmic artery segments (p = 0.0002). We demonstrated that locating the IOA and EOA segments can be achieved using the edge of the ICA as a reference point. OA: ophthalmic artery; IOA: intracranial segments of the ophthalmic artery; EOA: extracranial segments of the ophthalmic artery; ICA: internal carotid artery; UT: ultrasonic transducer; HTG: high tension glaucoma; SD: standard deviation; ICP: intracranial pressure; TCD: transcranial Doppler.

  13. Serum Endoglin Levels in Patients Suffering from Systemic Sclerosis and Elevated Systolic Pulmonary Arterial Pressure

    Directory of Open Access Journals (Sweden)

    Paola Ximena Coral-Alvarado

    2010-01-01

    Full Text Available Background. Pulmonary arterial hypertension (PAH is the main cause of morbimortality in systemic sclerosis (SSc. Increased Eng expression has been demonstrated in SSc patients. Objective. Ascertaining serum levels of Eng in SSc patients with and without elevated systolic pulmonary arterial pressure (sPAP and comparing them with that of healthy volunteers. Methods. A cross-sectional study was carried out. A commercial ELISA kit was used for measuring serum concentrations of Eng in 60 subjects: 40 patients with SSc with and without elevated sPAP, compared to 20 healthy control subjects. Elevated sPAP was detected by echocardiogram. Results. No association between positive Eng and elevated sPAP was found when compared to the SSc without elevated sPAP group (OR=2.85; 0.65–12.88 95% CI; P=.11; however, an association was found between positive Eng and elevated sPAP compared to healthy controls (OR=23.22; 2.46–1050.33 95% CI; P=.001, and weak association was found between the positive Eng with SSc without elevated sPAP group compared to healthy controls (OR=8.14, 0.8–393.74 95% CI; P=.046. Conclusion. Raised serum levels of Eng in SSc patients compared to healthy controls were found, suggesting a role for Eng in SSc vasculopathy and not just in elevated sPAP. However, prospective studies are needed to verify such observations.

  14. Experimental and modelling study of the effect of elevated pressure on ethane and propane flames

    NARCIS (Netherlands)

    Goswami, M.; Bastiaans, R.J.M.; de Goey, L.P.H.; Konnov, A.A.

    2016-01-01

    Laminar burning velocities, SL, of ethane + air and propane + air flames within an equivalence ratio range between 0.8 and 1.3 were determined at atmospheric and elevated pressures up to 4 atm. Measurements were performed in non-stretched flames, stabilized on a perforated plate burner at adiabatic

  15. Full characterization of multiphase, multimorphological kinetics in flow-induced crystallization of IPP at elevated pressure

    NARCIS (Netherlands)

    Troisi, E.M.; Caelers, H.J.M.; Peters, G.W.M.

    2017-01-01

    Understanding the complex crystallization behavior of isotactic polypropylene (iPP) in conditions comparable to those found in polymer processing, where the polymer melt experiences a combination of high shear rates and elevated pressures, is key for modeling and therefore predicting the final

  16. Acetone photophysics at 282 nm excitation at elevated pressure and temperature. II: Fluorescence modeling

    Science.gov (United States)

    Hartwig, Jason; Raju, Mandhapati; Sung, Chih-Jen

    2017-07-01

    This is the second in a series of two papers that presents an updated fluorescence model and compares with the new experimental data reported in the first paper, as well as the available literature data, to extend the range of acetone photophysics to elevated pressure and temperature conditions. This work elucidates the complete acetone photophysical model in terms of each and every competing radiative and non-radiative rate. The acetone fluorescence model is then thoroughly examined and optimized based on disparity with recently conducted elevated pressure and temperature photophysical calibration experiments. The current work offers insight into the competition between non-radiative and vibrational energy decay rates at elevated temperature and pressure and proposes a global optimization of model parameters from the photophysical model developed by Thurber (Acetone Laser-Induced Fluorescence for Temperature and Multiparameter Imaging in Gaseous Flows. PhD thesis, Stanford University Mechanical Engineering Department, 1999). The collisional constants of proportionality, which govern vibrational relaxation, are shown to be temperature dependent at elevated pressures. A new oxygen quenching rate is proposed which takes into account collisions with oxygen as well as the oxygen-assisted intersystem crossing component. Additionally, global trends in ketone photophysics are presented and discussed.

  17. Time-Resolved WAXD and SAXS Investigations on Butyl Branched Alkane at Elevated Pressures

    NARCIS (Netherlands)

    Rastogi, A.; Hobbs, J.K.; Rastogi, S.

    2002-01-01

    The crystallization behavior and the morphological aspect of the butyl branched alkane C96H193CH(C4H9)C94H189 have been investigated using time-resolved wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) at atmospheric and elevated pressures. The solution crystallized sample

  18. The role of hypertension in bromocriptine-related puerperal intracranial hemorrhage

    International Nuclear Information System (INIS)

    Kirsch, C.; Iffy, L.; Zito, G.E.; McArdle, J.J.

    2001-01-01

    The spate of medicolegal inquiries following the disqualification of Parlodel (bromocriptine mesylate) by the Food and Drug Administration for postpartum ablactation, uncovered previously unreported side effects associated with its postpartum administration. In 1994, bromocriptine mesylate was withdrawn from the market as a milk suppressant. Since this time, over a dozen cases of postpartum intracranial hemorrhages associated with its use have been reported. We describe three additional cases of postpartum intracranial hemorrhage related to bromocriptine usage. One patient, previously normotensive, developed hypertension and a headache; initial CT was normal, but CT 24 h later demonstrated intracranial hemorrhage. This suggests that the blood-pressure elevation was drug-induced and was the cause, rather than the consequence, of bromocriptine-related intracranial hemorrhage. (orig.)

  19. The role of hypertension in bromocriptine-related puerperal intracranial hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Kirsch, C. [Dept. of Radiology, University Hospital, Newark, NJ (United States); Iffy, L. [Dept. of Obstetrics, Gynecology and Womens Health, University Hospital, Newark, NJ (United States); Zito, G.E. [Dept. of Neurology, University Hospital, Newark, NJ (United States); McArdle, J.J. [Dept. of Pharmacology, University Hospital, Newark, NJ (United States)

    2001-04-01

    The spate of medicolegal inquiries following the disqualification of Parlodel (bromocriptine mesylate) by the Food and Drug Administration for postpartum ablactation, uncovered previously unreported side effects associated with its postpartum administration. In 1994, bromocriptine mesylate was withdrawn from the market as a milk suppressant. Since this time, over a dozen cases of postpartum intracranial hemorrhages associated with its use have been reported. We describe three additional cases of postpartum intracranial hemorrhage related to bromocriptine usage. One patient, previously normotensive, developed hypertension and a headache; initial CT was normal, but CT 24 h later demonstrated intracranial hemorrhage. This suggests that the blood-pressure elevation was drug-induced and was the cause, rather than the consequence, of bromocriptine-related intracranial hemorrhage. (orig.)

  20. Standardized Application of Laxatives and Physical Measures in Neurosurgical Intensive Care Patients Improves Defecation Pattern but Is Not Associated with Lower Intracranial Pressure

    Directory of Open Access Journals (Sweden)

    Martin Kieninger

    2014-01-01

    Full Text Available Background. Inadequate bowel movements might be associated with an increase in intracranial pressure in neurosurgical patients. In this study we investigated the influence of a structured application of laxatives and physical measures following a strict standard operating procedure (SOP on bowel movement, intracranial pressure (ICP, and length of hospital stay in patients with a serious acute cerebral disorder. Methods. After the implementation of the SOP patients suffering from a neurosurgical disorder received pharmacological and nonpharmacological measures to improve bowel movements in a standardized manner within the first 5 days after admission to the intensive care unit (ICU starting on day of admission. We compared mean ICP levels, length of ICU stay, and mechanical ventilation to a historical control group. Results. Patients of the intervention group showed an adequate defecation pattern significantly more often than the patients of the control group. However, this was not associated with lower ICP values, fewer days of mechanical ventilation, or earlier discharge from ICU. Conclusions. The implementation of a SOP for bowel movement increases the frequency of adequate bowel movements in neurosurgical critical care patients. However, this seems not to be associated with reduced ICP values.

  1. Standardized application of laxatives and physical measures in neurosurgical intensive care patients improves defecation pattern but is not associated with lower intracranial pressure.

    Science.gov (United States)

    Kieninger, Martin; Sinner, Barbara; Graf, Bernhard; Grassold, Astrid; Bele, Sylvia; Seemann, Milena; Künzig, Holger; Zech, Nina

    2014-01-01

    Background. Inadequate bowel movements might be associated with an increase in intracranial pressure in neurosurgical patients. In this study we investigated the influence of a structured application of laxatives and physical measures following a strict standard operating procedure (SOP) on bowel movement, intracranial pressure (ICP), and length of hospital stay in patients with a serious acute cerebral disorder. Methods. After the implementation of the SOP patients suffering from a neurosurgical disorder received pharmacological and nonpharmacological measures to improve bowel movements in a standardized manner within the first 5 days after admission to the intensive care unit (ICU) starting on day of admission. We compared mean ICP levels, length of ICU stay, and mechanical ventilation to a historical control group. Results. Patients of the intervention group showed an adequate defecation pattern significantly more often than the patients of the control group. However, this was not associated with lower ICP values, fewer days of mechanical ventilation, or earlier discharge from ICU. Conclusions. The implementation of a SOP for bowel movement increases the frequency of adequate bowel movements in neurosurgical critical care patients. However, this seems not to be associated with reduced ICP values.

  2. Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat-stressed humans

    Science.gov (United States)

    Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

    2002-01-01

    To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat-stressed humans, blood pressure was elevated via steady-state infusion of three doses of phenylephrine HCl in 10 healthy subjects in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature by 0.5 degrees C, muscle sympathetic nerve activity (MSNA), heart rate, and cardiac output and decreased total peripheral vascular resistance (TPR; all P blood pressure (MAP; P > 0.05). At the highest dose of phenylephrine, the increase in MAP and TPR from predrug baselines was significantly attenuated during the heat stress [DeltaMAP 8.4 +/- 1.2 mmHg; DeltaTPR 0.96 +/- 0.85 peripheral resistance units (PRU)] compared with normothermia (DeltaMAP 15.4 +/- 1.4 mmHg, DeltaTPR 7.13 +/- 1.18 PRU; all P blood pressure, as well as the slope of the relationship between heart rate and systolic blood pressure, respectively, was similar between thermal conditions (each P > 0.05). These data suggest that phenylephrine-induced elevations in MAP are attenuated in heat-stressed humans without affecting baroreflex control of MSNA or heart rate.

  3. Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures

    Science.gov (United States)

    Ohtsuka, Masaya; Yoshida, Shohei; Hirata, Yoshitaka; Kobayashi, Nariyoshi

    Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ˜100Hz and ˜350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ˜80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.

  4. Frequency of diarrhoea as a predictor of elevated blood pressure in children

    Science.gov (United States)

    Miranda, Juan Jaime; Davies, Alisha R.; Smith, George Davey; Smeeth, Liam; Cabrera, Lilia; Gilman, Robert H.; García, Héctor H.; Ortega, Ynes R.; Cama, Vitaliano A.

    2009-01-01

    Background Diarrhoeal illness is a major public health problem for children worldwide, particularly among developing countries, and is a proxy condition for severe dehydration. It has been hypothesized that severe dehydration in the first 6 months of life could be associated with increased blood pressure later in life. This study aimed to explore whether frequency of diarrhoea is associated with elevated blood pressure in children in a setting with a high incidence of diarrhoeal disease. Methods The present study is a cross-sectional study of blood pressure among children from a longitudinal child diarrhoeal disease cohort in Lima, Peru. From 2001 to 2006, daily diarrhoeal surveillance was made. Children were revisited in 2006 and blood pressure was measured. Diarrhoeal exposures were evaluated in terms of total number of diarrhoea days, number of episodes of diarrhoea, persistent diarrhoeal episodes and by the quartiles of daily incidence and episode incidence of diarrhoea. Results The overall incidence of diarrhoeal episodes at age under 1 year was 4.35 (95% confidence interval: 3.79-4.98) and under 5 years was 2.80 (95% confidence interval: 2.69-2.92). No association was observed between the total number of diarrhoeal days, diarrhoeal episodes or diarrhoeal incidence rates with childhood blood pressure. There was weak evidence that hospital admission due to severe dehydration in the first year of life showed a gradient towards an increase in both, systolic and diastolic blood pressure. Conclusion In the first study to date to examine the association in a setting with a high incidence of diarrhoeal disease, diarrhoeal frequency did not show an association with increased blood pressure. Our observations of elevated levels of blood pressure among those admitted into hospitals in the first year of life are in line with the original hypothesis of dehydration in early infancy and high blood pressure. However, the effect of episodes of severe dehydration on later blood

  5. The relationship between elevated interstitial fluid pressure and blood flow in tumors: a bioengineering analysis

    International Nuclear Information System (INIS)

    Milosevic, Michael F.; Fyles, Anthony W.; Hill, Richard P.

    1999-01-01

    Purpose: To examine the hypothesis that elevated interstitial fluid pressure (IFP) is a cause of reduced blood flow in tumors. Materials and Methods: A physiologic model of tumor blood flow was developed based on a semipermeable, compliant capillary in the center of a spherical tumor. The model incorporates the interaction between the tumor vasculature and the interstitium, as mediated by IFP. It also incorporates the dynamic behavior of the capillary wall in response to changes in transmural pressure, and the effect of viscosity on blood flow. Results: The model predicted elevated tumor IFP in the range of 0 to 56 mmHg. The capillary diameter in the setting of elevated IFP was greatest at the arterial end, and constricted to between 3.2 and 4.4 μm at the venous end. This corresponded to a 2.4- to 3.5-fold reduction in diameter along the length of the capillary. The IFP exceeded the intravascular pressure distally in the capillary, but vascular collapse did not occur. Capillary diameter constriction resulted in a 2.3- to 9.1-fold steady-state reduction in tumor blood flow relative to a state of near-zero IFP. Conclusion: The results suggest that steady-state vascular constriction occurs in the setting of elevated IFP, and leads to reduced tumor blood flow. This may in turn contribute to the development of hypoxia, which is an important cause of radiation treatment failure in many tumors

  6. Evaulation of Incidence and Risk Factors for Intraocular Pressure Elevation After Intravitreal Triamcinolone Acetonide Injection

    Directory of Open Access Journals (Sweden)

    Didar Uçar

    2015-05-01

    Full Text Available Objectives: To investigate the effect of intravitreal triamcinolone acetonide (IVTA used for the macular edema on intraocular pressure (IOP and to determine the risk factors for IOP elevation. Materials and Methods: This retrospective study included 93 eyes of 85 patients who had 4 mg intravitreal triamcinolone injection. Of the 85 patients, 56 (65.8% had diabetic macular edema, 22 (25.8% had branch retinal, and 7 (8.2% had central retinal vein occlusion. IOP changes after injection as well as the relation between IOP elevation and age, sex, lens status, etiology of macular edema, baseline IOP were evaluated. Results: Fourty-six male and 39 female patients with mean age 61.58±9.5 years were evaluated. IOP was recorded to be >24 mmHg in 30 eyes (32.2% at follow-up visit after an average of 7.5 weeks. Normalization of IOP with medication was achieved in all IOP elevated eyes. Fifteen of 29 eyes (51.7% with vein occlusion and 15 of 64 eyes (23.3% with diabetic macula edema had IOP elevation (p=0.01. Twenty-six of 73 phakic (35.6% and 4 of 20 pseudophakic eyes (20% had IOP >24 mmHg (p=0.16. There was no association between IOP elevation and sex (p=0.33. Baseline IOP was 16.47±2.8 mmHg in eyes which had elevated IOP and 14.78±2.4 mmHg in the remaining. There was significant relation between IOP elevation and baseline IOP level (p=0.01. Conclusion: Elevated IOP is common side effect after IVTA, but normalization is usually achieved by topical medication. Patients with baseline IOP ≥15 mmHg and vein occlusion have higher risk for IOP elevation. (Turk J Ophthalmol 2015; 45: 86-91

  7. Desirability of oysters treated by high pressure processing at different temperatures and elevated pressures

    Science.gov (United States)

    Organoleptic changes in sterile triploid oysters (Crassostrea virginica) induced by high pressure processing (HPP) were investigated using a volunteer panel. Using a 1-7 hedonic scale, where seven is “like very much”, and one is “dislike very much”, oysters were evaluated organoleptically for flavo...

  8. Intracranial sarcoidosis

    International Nuclear Information System (INIS)

    Seltzer, S.; Mark, A.S.; Atlas, S.W.

    1989-01-01

    The appearance of intracranial sarcoidosis on Gd-DTPA-enhanced MR imaging has not been previously reported. The authors have studied five patients with T1-and T2-weighted pre-GD and T1-weighted post-GD sequences. Images showed diffuse meningeal involvement suspected on the unenhanced scans in only one patient, enhancing extraaxial masses mimicking meningiomas, and enhancing and nonenhancing intraaxial lesions. In four of five patients, the diagnosis of intracranial sarcoidosis was suggested only after Gd-DTPA administration. The addition of Gd-DTPA greatly enhanced the sensitivity of MR imaging to the extraaxial and meningeal manifestations of central nervous system sarcoidosis

  9. Associations between adiposity indicators and elevated blood pressure among Chinese children and adolescents.

    Science.gov (United States)

    Dong, B; Wang, Z; Wang, H-J; Ma, J

    2015-04-01

    Adiposity is closely related to elevated blood pressure (BP); however, which adiposity indicator is the best predictor of elevated BP among children and adolescents is unclear. To clarify this, 99,366 participants aged 7-17 years from the Chinese National Survey on Students' Constitution and Health in 2010 were included in this study. The adiposity indicators, including weight, body mass index (BMI), waist circumference, waist-to-height ratio (WHtR), hip circumference, body adiposity index (BAI), waist-to-hip ratio (WHR) and skinfold thickness, were converted into z-scores before use. The associations between elevated BP and adiposity indicators z-scores were assessed by using logistic regression model and area under the receiver operating characteristic curve (AUC). In general, BAI, BMI and WHtR z-scores were superior for predicting elevated BP compared with weight, waist circumference, hip circumference, WHR and skinfold thickness z-scores. In both sexes, BMI z-score revealed slightly higher AUCs than other indicators. Our findings suggest that general adiposity indicators were equivalent, if not superior, to abdominal adiposity indicators to predict elevated BP. BMI could be a better predictor of elevated BP than other studied adiposity indicators in children.

  10. Elevated intrabolus pressure identifies obstructive processes when integrated relaxation pressure is normal on esophageal high-resolution manometry.

    Science.gov (United States)

    Quader, Farhan; Reddy, Chanakyaram; Patel, Amit; Gyawali, C Prakash

    2017-07-01

    Elevated integrated relaxation pressure (IRP) on esophageal high-resolution manometry (HRM) identifies obstructive processes at the esophagogastric junction (EGJ). Our aim was to determine whether intrabolus pressure (IBP) can identify structural EGJ processes when IRP is normal. In this observational cohort study, adult patients with dysphagia and undergoing HRM were evaluated for endoscopic evidence of structural EGJ processes (strictures, rings, hiatus hernia) in the setting of normal IRP. HRM metrics [IRP, distal contractile integral (DCI), distal latency (DL), IBP, and EGJ contractile integral (EGJ-CI)] were compared among 74 patients with structural EGJ findings (62.8 ± 1.6 yr, 67.6% women), 27 patients with normal EGD (52.9 ± 3.2 yr, 70.3% women), and 21 healthy controls (27.6 ± 0.6 yr, 52.4% women). Findings were validated in 85 consecutive symptomatic patients to address clinical utility. In the primary cohort, mean IBP (18.4 ± 0.9 mmHg) was higher with structural EGJ findings compared with dysphagia with normal EGD (13.5 ± 1.1 mmHg, P = 0.002) and healthy controls (10.9 ± 0.9 mmHg, P 0.05 for each comparison). During multiple rapid swallows, IBP remained higher in the structural findings group compared with controls ( P = 0.02). Similar analysis of the prospective validation cohort confirmed IBP elevation in structural EGJ processes, but correlation with dysphagia could not be demonstrated. We conclude that elevated IBP predicts the presence of structural EGJ processes even when IRP is normal, but correlation with dysphagia is suboptimal. NEW & NOTEWORTHY Integrated relaxation pressure (IRP) above the upper limit of normal defines esophageal outflow obstruction using high-resolution manometry. In patients with normal IRP, elevated intrabolus pressure (IBP) can be a surrogate marker for a structural restrictive or obstructive process at the esophagogastric junction (EGJ). This has the potential to augment the clinical value of

  11. Idiopathic intracranial hypertension, hormones, and 11β-hydroxysteroid dehydrogenases

    DEFF Research Database (Denmark)

    Markey, Keira A; Uldall, Maria; Botfield, Hannah

    2016-01-01

    Idiopathic intracranial hypertension (IIH) results in raised intracranial pressure (ICP) leading to papilledema, visual dysfunction, and headaches. Obese females of reproductive age are predominantly affected, but the underlying pathological mechanisms behind IIH remain unknown. This review provi...

  12. Association of benign intracranial hypertension and spontaneous encephalocele with cerebrospinal fluid leak.

    Science.gov (United States)

    Brainard, Laura; Chen, Douglas A; Aziz, Khaled M; Hillman, Todd A

    2012-12-01

    To determine the incidence of intracranial hypertension in patients with spontaneous encephalocele with cerebrospinal fluid (CSF) leak. Retrospective case review. Tertiary care neurotology practice. Patients presenting between 2008 and 2011 with spontaneous encephalocele and CSF leak in the temporal bone. Lumbar puncture with opening pressure measurement after encephalocele repair. Patient age, sex, postoperative course, body mass index, and postoperative intracranial pressure. Of the 26 patients identified with spontaneous encephalocele with CSF leak, 9 patients had postoperative lumbar puncture data. Of those 9, 89% were female subjects, and 11% were male, with a mean age of 57 and a mean BMI of 41 kg/m (morbidly obese). The mean opening pressure was 24.5 cm H(2)O. Approximately 33% had normal intracranial pressure (mean, 15 cm H(2)O; range, 10-17 cm H(2)O); 67% had elevated intracranial pressure (mean, 29 cm H(2)O; range, 23.5-40 cm H(2)O). The incidence of BIH in the general population is 0.001%. Of the 6 with intracranial hypertension, 3 (50%) were placed on acetazolamide for fundoscopic findings, postoperative headache, and/or visual changes. Mean time to LP after repair of encephalocele was 13 months (range, 4 days to 75 months). This study shows that benign intracranial hypertension is prevalent in a significant number of patients presenting with spontaneous encephalocele with CSF otorrhea at a rate much higher than is found in the general population. This finding has direct clinical implications and suggests that all patients with spontaneous encephalocele/CSF leak warrant evaluation for benign intracranial hypertension.

  13. Integration optimisation of elevated pressure air separation unit with gas turbine in an IGCC power plant

    International Nuclear Information System (INIS)

    Han, Long; Deng, Guangyi; Li, Zheng; Wang, Qinhui; Ileleji, Klein E.

    2017-01-01

    Highlights: • IGCC thermodynamic model was setup carefully. • Simulations focus on integration between an elevated pressure ASU with gas turbine. • Different recommended solutions from those of low pressure ASUs are figured out. • Full N 2 injection and 80% air extraction was suggested as the optimum integration. - Abstract: The integration optimisation between an elevated pressure air separation unit (EP-ASU) and gas turbine is beneficial to promote net efficiency of an integrated gasification combined cycle (IGCC) power plant. This study sets up the thermodynamic model for a 400 MW plant specially coupled with an EP-ASU, aiming to examine system performances under different integrations and acquire the optimum solution. Influences of air extraction rate at conditions of without, partial and full N 2 injection, as well as the effects of N 2 injection rate when adopting separate ASU, partial and full integrated ASU were both analysed. Special attention has been paid to performance differences between utilising an EP-ASU and a low pressure unit. Results indicated that integration solution with a separate EP-ASU or without N 2 injection would not be reasonable. Among various recommended solutions for different integration conditions, N 2 injection rate increased with the growth of air extraction rate. The integration with an air extraction rate of 80% and full N 2 injection was suggested as the optimum solution. It is concluded that the optimum integration solution when adopting an EP-ASU is different from that using a low pressure one.

  14. Hydrodynamics in a cocurrent gas-liquid trickle bed at elevated pressures

    OpenAIRE

    Wammes, W.J.A.; Middelkamp, J.; Huisman, W.J.; Huisman, W.J.; de Baas, C.M.; de Baas, C.M.; Westerterp, K.R.

    1991-01-01

    Data on design and operation of trickle beds at elevated pressures are scarce. In this study the influence of the gas density on the liquid holdup, the pressure drop, and the transition between trickle and pulse flow has been investigated in a tricklebed reactor operating up to 7.5 MPa and with nitrogen or helium as the gas phase. Gas-liquid interfacial areas have been determined up to 5.0 MPa by means of CO2 absorption from CO2/N2 gas mixtures into amine solutions. A comparison of the result...

  15. Calpain: a molecule to induce AIF-mediated necroptosis in RGC-5 following elevated hydrostatic pressure

    Science.gov (United States)

    2014-01-01

    Background RIP3 (Receptor-interacting protein 3) pathway was mainly described as the molecular mechanism of necroptosis (programmed necrosis). But recently, non-RIP3 pathways were found to mediate necroptosis. We deliberate to investigate the effect of calpain, a molecule to induce necroptosis as reported (Cell Death Differ 19:245–256, 2012), in RGC-5 following elevated hydrostatic pressure. Results First, we identified the existence of necroptosis of RGC-5 after insult by using necrostatin-1 (Nec-1, necroptosis inhibitor) detected by flow cytometry. Immunofluorescence staining and western blot were used to detect the expression of calpain. Western blot analysis was carried out to describe the truncated AIF (tAIF) expression with or without pretreatment of ALLN (calpain activity inhibitor). Following elevated hydrostatic pressure, necroptotic cells pretreated with or without ALLN was stained by Annexin V/PI, The activity of calpain was also examined to confirm the inhibition effect of ALLN. The results showed that after cell injury there was an upregulation of calpain expression. Upon adding ALLN, the calpain activity was inhibited, and tAIF production was reduced upon injury along with the decreased number of necroptosis cells. Conclusion Our study found that calpain may induce necroptosis via tAIF-modulation in RGC-5 following elevated hydrostatic pressure. PMID:24884644

  16. Soot particle size measurements in ethylene diffusion flames at elevated pressures

    KAUST Repository

    Steinmetz, Scott

    2016-05-07

    Soot particle size is investigated in laminar nitrogen-diluted ethylene coflow diffusion flames at 4, 8, 12 and 16 atm. Line of sight attenuation and scattering are used to measure two-dimensional soot volume fraction and particle size fields for the first time at elevated pressures. Soot volume fraction dependence on pressure is consistent with the observations of similar studies, scaling approximately with the square of pressure. Scattering intensity is analyzed through Rayleigh and Rayleigh-Debye-Gans polydisperse fractal aggregate theories to provide two estimates of particle size. An increase in overall particle sizes with pressure is found, consistent with similar one-dimensional studies. Particle diameters in the annulus of the flame increase faster with pressure than those on centerline. Contrary to previous studies, the dependence of particle size on pressure was found to taper off between 8 and 12 atm, with little observed growth beyond 12 atm. The measurements provide additional data for one of the International Sooting Flame (ISF) workshop\\'s target pressurized flames.

  17. Effects of Simulation With Problem-Based Learning Program on Metacognition, Team Efficacy, and Learning Attitude in Nursing Students: Nursing Care With Increased Intracranial Pressure Patient.

    Science.gov (United States)

    Lee, Myung-Nam; Nam, Kyung-Dong; Kim, Hyeon-Young

    2017-03-01

    Nursing care for patients with central nervous system problems requires advanced professional knowledge and care skills. Nursing students are more likely to have difficulty in dealing with adult patients who have severe neurological problems in clinical practice. This study investigated the effect on the metacognition, team efficacy, and learning attitude of nursing students after an integrated simulation and problem-based learning program. A real scenario of a patient with increased intracranial pressure was simulated for the students. The results showed that this method was effective in improving the metacognitive ability of the students. Furthermore, we used this comprehensive model of simulation with problem-based learning in order to assess the consequences of student satisfaction with the nursing major, interpersonal relationships, and importance of simulation-based education in relation to the effectiveness of the integrated simulation with problem-based learning. The results can be used to improve the design of clinical practicum and nursing education.

  18. Elevated plasma endothelin-1 and pulmonary arterial pressure in children exposed to air pollution.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J; Reed, William

    2007-08-01

    Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O(3) that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. We conducted a study of 81 children, 7.9 +/- 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O(3) levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 mum in aerodynamic diameter (PM(2.5)) before endothelin-1 measurement (p = 0.03). Chronic exposure of children to PM(2.5) is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure.

  19. Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J.; Reed, William

    2007-01-01

    Background Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. Objectives The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. Methods We conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Results Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03). Conclusions Chronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure. PMID:17687455

  20. What Is IH (Intracranial Hypertension)?

    Science.gov (United States)

    ... Store What is IH? What is IH? Intracranial hypertension literally means that the pressure of cerebrospinal fluid ( ... is too high. “Intracranial” means “within the skull.” “Hypertension” means “high fluid pressure.” To understand how this ...

  1. Elevated pulse pressure is associated with hemolysis, proteinuria and chronic kidney disease in sickle cell disease.

    Directory of Open Access Journals (Sweden)

    Enrico M Novelli

    Full Text Available A seeming paradox of sickle cell disease is that patients do not suffer from a high prevalence of systemic hypertension in spite of endothelial dysfunction, chronic inflammation and vasculopathy. However, some patients do develop systolic hypertension and increased pulse pressure, an increasingly recognized major cardiovascular risk factor in other populations. Hence, we hypothesized that pulse pressure, unlike other blood pressure parameters, is independently associated with markers of hemolytic anemia and cardiovascular risk in sickle cell disease. We analyzed the correlates of pulse pressure in patients (n  =  661 enrolled in a multicenter international sickle cell trial. Markers of hemolysis were analyzed as independent variables and as a previously validated hemolytic index that includes multiple variables. We found that pulse pressure, not systolic, diastolic or mean arterial pressure, independently correlated with high reticulocyte count (beta  =  2.37, p  =  0.02 and high hemolytic index (beta  =  1.53, p = 0.002 in patients with homozygous sickle cell disease in two multiple linear regression models which include the markers of hemolysis as independent variables or the hemolytic index, respectively. Pulse pressure was also independently associated with elevated serum creatinine (beta  =  3.21, p  =  0.02, and with proteinuria (beta  =  2.52, p  =  0.04. These results from the largest sickle cell disease cohort to date since the Cooperative Study of Sickle Cell Disease show that pulse pressure is independently associated with hemolysis, proteinuria and chronic kidney disease. We propose that high pulse pressure may be a risk factor for clinical complications of vascular dysfunction in sickle cell disease. Longitudinal and mechanistic studies should be conducted to confirm these hypotheses.

  2. Osmolality of Cerebrospinal Fluid from Patients with Idiopathic Intracranial Hypertension (IIH)

    DEFF Research Database (Denmark)

    Wibroe, Elisabeth A; Yri, Hanne M; Jensen, Rigmor H

    2016-01-01

    INTRODUCTION: Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial fluid pressure (ICP) of unknown etiology. This study aims to investigate osmolality of cerebrospinal fluid (CSF) from patients with IIH. METHODS: We prospectively collected CSF from individuals referred...... significantly from patients with moderately elevated ICP from 26-45 cmH2O (n = 21) (p = 0.86) and patients with high ICP from 46-70 cmH2O (n = 4) (p = 0.32), respectively. There was no correlation between osmolality and ICP, BMI, age and body height, respectively. Mean CSF osmolality was 270 mmol/kg (± 1 SE, 95...

  3. Density and Viscosity Measurement of Diesel Fuels at Combined High Pressure and Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Carl Schaschke

    2013-07-01

    Full Text Available We report the measurement of the viscosity and density of various diesel fuels, obtained from British refineries, at elevated pressures up to 500 MPa and temperatures in the range 298 K to 373 K. The measurement and prediction procedures of fluid properties under high pressure conditions is of increasing interest in many processes and systems including enhanced oil recovery, automotive engine fuel injection, braking, and hydraulic systems. Accurate data and understanding of the fluid characteristic in terms of pressure, volume and temperature is required particularly where the fluid is composed of a complex mixture or blend of aliphatic or aromatic hydrocarbons. In this study, high pressure viscosity data was obtained using a thermostatically-controlled falling sinker-type high pressure viscometer to provide reproducible and reliable viscosity data based on terminal velocity sinker fall times. This was supported with density measurements using a micro-pVT device. Both high-pressure devices were additionally capable of illustrating the freezing points of the hydrocarbon mixtures. This work has, thus, provided data that can extend the application of mixtures of commercially available fuels and to test the validity of available predictive density and viscosity models. This included a Tait-style equation for fluid compressibility prediction. For complex diesel fuel compositions, which have many unidentified components, the approach illustrates the need to apply appropriate correlations, which require accurate knowledge or prediction of thermodynamic properties.

  4. Myocardial Ischaemia, Coronary Atherosclerosis and Pulmonary Pressure Elevation in Antiphospholipid Syndrome Patients.

    Science.gov (United States)

    Padjas, Agnieszka; Płazak, Wojciech; Celińska-Lowenhoff, Magdalena; Mazurek, Adam; Perricone, Carlo; Podolec, Piotr; Musiał, Jacek

    2016-01-01

    Thrombotic events in antiphospholipid syndrome (APS) involve venous and arterial circulation with the possible involvement of coronary or pulmonary microcirculation. To evaluate the influence of antiphospholipid antibodies (aPL) and on myocardial ischaemia assessed by single-photon emission computerized tomography (SPECT), coronary atherosclerosis assessed by multidetector computerized tomography (MDCT) and pulmonary pressure assessed by transthoracic echocardiography (TTE) in patients with primary antiphospholipid syndrome (PAPS). TTE, SPECT (Tc 99m sestamibi) and MDCT-based coronary calcium scoring were performed in 26 consecutive PAPS patients (20 females, 6 males, aged 20-61, mean 39.7) without any signs of other autoimmunological disease and without clinical symptoms of heart disease. Out of 26 patients, TEE showed normal left and right ventricle function in 25 (96.2%) and elevated (≥ 30 mm Hg) right ventricle systolic pressure in 7 (26.9%) patients. SPECT revealed myocardial perfusion defects in 15 (57.7%) patients: exercise-induced in 6 (23.1%) and persistent in 11 (42.3%). MDCT revealed coronary calcifications in 4 (15.4%) patients. The number of plaques ranged from 1 to 11 (median 2), volume 3-201.7 mm³ (median 7), calcium scores 1.3-202.6 (median 5.7). In the group with perfusion defects or coronary calcifications (n = 15), all the patients showed elevated aCL IgG. In most of the relatively young APS patients, without any symptoms of ischemic heart disease, SPECT showed myocardial perfusion defects, and coronary calcifications in 1/6 of them. Right ventricle systolic pressure was elevated in 1/4 of APS patients. These pathologies, well known as cardiovascular risk markers, were associated with elevated levels of the IgG class of both anti-cardiolipin and antiB2 GPI antibodies. Thus, in a high percentage of APS patients, clinically silent myocardial ischaemia, pulmonary pressure elevation and coronary atherosclerosis are present and related to the

  5. Pressure drop in packed beds of spherical particles at ambient and elevated air temperatures

    Directory of Open Access Journals (Sweden)

    Pešić Radojica

    2015-01-01

    Full Text Available The aim of this work was the experimental investigation of the particle friction factor for air flow through packed bed of particles at ambient and elevated temperatures. The experiments were performed by measuring the pressure drop across the packed bed, heated to the desired temperature by hot air. Glass spherical particles of seven different diameters were used. The temperature range of the air flowing through the packed bed was from 20ºC to 350ºC and the bed voidages were from 0.3574 to 0.4303. The obtained results were correlated using a number of available literature correlations. The overall best fit of all of the experimental data was obtained using Ergun [1] equation, with mean absolute deviation of 10.90%. Ergun`s equation gave somewhat better results in correlating the data at ambient temperature with mean absolute deviation of 9.77%, while correlation of the data at elevated temperatures gave mean absolute deviation of 12.38%. The vast majority of the correlations used gave better results when applied to ambient temperature data than to the data at elevated temperatures. Based on the results obtained, Ergun [1] equation is proposed for friction factor calculation both at ambient and at elevated temperatures. [Projekat Ministarstva nauke Republike Srbije, br. ON172022

  6. Intracranial Hypertension Research Foundation

    Science.gov (United States)

    ... PARTNERSHIPS Meet our Fundraising Partners Tweet Welcome Intracranial hypertension (IH) is the general term for the neurological ... high. (Old names for IH include Benign Intracranial Hypertension and Pseudotumor Cerebri). The Intracranial Hypertension Research Foundation ...

  7. Equilibrium moisture content of radiata pine at elevated temperature and pressure reveals measurement challenges

    DEFF Research Database (Denmark)

    Pearson, Hamish; Gabbitas, Brian; Ormarsson, Sigurdur

    2012-01-01

    moisture contents were attributed to condensation of liquid water on the specimen with subsequent evaporation at a rate that was too slow for the moisture content to reach equilibrium before it was measured. Reliable EMC data at elevated temperatures require (1) tight process control of experimental......Relatively few studies have been performed on the equilibrium moisture content (EMC) of wood under conditions of elevated temperature and pressure. Eight studies indicated that EMC near saturation decreased between 100 and 150 °C, whilst five studies indicated that EMC increased. The aim...... of this study was to identify the likely source of the disagreement using radiata pine (Pinus radiata D. Don) sapwood which was conditioned to a moisture content of around 3 % and then exposed for 1 h at 150 °C and relative humidities of either 50, 70 or 90 %. Mean values of EMC, obtained through in situ...

  8. Spaceflight-Induced Intracranial Hypertension and Visual Impairment: Pathophysiology and Countermeasures.

    Science.gov (United States)

    Zhang, Li-Fan; Hargens, Alan R

    2018-01-01

    Visual impairment intracranial pressure (VIIP) syndrome is considered an unexplained major risk for future long-duration spaceflight. NASA recently redefined this syndrome as Spaceflight-Associated Neuro-ocular Syndrome (SANS). Evidence thus reviewed supports that chronic, mildly elevated intracranial pressure (ICP) in space (as opposed to more variable ICP with posture and activity on Earth) is largely accounted for by loss of hydrostatic pressures and altered hemodynamics in the intracranial circulation and the cerebrospinal fluid system. In space, an elevated pressure gradient across the lamina cribrosa, caused by a chronic but mildly elevated ICP, likely elicits adaptations of multiple structures and fluid systems in the eye which manifest themselves as the VIIP syndrome. A chronic mismatch between ICP and intraocular pressure (IOP) in space may acclimate the optic nerve head, lamina cribrosa, and optic nerve subarachnoid space to a condition that is maladaptive to Earth, all contributing to the pathogenesis of space VIIP syndrome. Relevant findings help to evaluate whether artificial gravity is an appropriate countermeasure to prevent this seemingly adverse effect of long-duration spaceflight. Copyright © 2018 the American Physiological Society.

  9. Liquid oxygen liquid acquisition device bubble point tests with high pressure lox at elevated temperatures

    Science.gov (United States)

    Jurns, J. M.; Hartwig, J. W.

    2012-04-01

    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth's gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMDs) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. The present work reports on testing with liquid oxygen (LOX) at elevated pressures (and thus temperatures) (maximum pressure 1724 kPa and maximum temperature 122 K) as part of NASA's continuing cryogenic LAD development program. These tests evaluate LAD performance for LOX stored in higher pressure vessels that may be used in propellant systems using pressure fed engines. Test data shows a significant drop in LAD bubble point values at higher liquid temperatures, consistent with lower liquid surface tension at those temperatures. Test data also indicates that there are no first order effects of helium solubility in LOX on LAD bubble point prediction. Test results here extend the range of data for LOX fluid conditions, and provide insight into factors affecting predicting LAD bubble point pressures.

  10. Acute surgical management in idiopathic intracranial hypertension.

    LENUS (Irish Health Repository)

    Zakaria, Zaitun

    2012-01-01

    Idiopathic intracranial hypertension is a headache syndrome with progressive symptoms of raised intracranial pressure. Most commonly, it is a slow process where surveillance and medical management are the main treatment modalities. We describe herein an acute presentation with bilateral sixth nerve palsies, papilloedema and visual deterioration, where acute surgical intervention was a vision-saving operation.

  11. Effect of renal venous pressure elevation on tubular sodium and water reabsorption in the dog kidney

    DEFF Research Database (Denmark)

    Abildgaard, U; Amtorp, O; Holstein-Rathlou, N H

    1988-01-01

    of [51Cr]EDTA was used as a measure of the rate of glomerular filtration (GFR). GFR, urinary excretion rates of sodium and water, and lithium clearance were used for assessing the absolute and fractional reabsorption rates of sodium and water in the proximal as well as in more distal segments......This study was performed in order to quantify the effects of renal venous pressure (RVP) elevation on absolute and fractional reabsorption rates of sodium and water in proximal and distal segments of the nephron in dog kidneys. Renal blood flow (RBF) was measured electromagnetically. Clearance...

  12. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

    Directory of Open Access Journals (Sweden)

    Joost W van Dam

    Full Text Available Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m, while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v/F(m, interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v/F(m and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1. The mixture toxicity model of Independent Action (IA described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  13. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

    Science.gov (United States)

    van Dam, Joost W; Negri, Andrew P; Mueller, Jochen F; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  14. The Risk of Intraocular Pressure Elevation in Pediatric Non-infectious Uveitis

    Science.gov (United States)

    Kothari, Srishti; Foster, C. Stephen; Pistilli, Maxwell; Liesegang, Teresa L.; Daniel, Ebenezer; Sen, H. Nida; Suhler, Eric B.; Thorne, Jennifer E.; Jabs, Douglas A.; Levy-Clarke, Grace A.; Nussenblatt, Robert B.; Rosenbaum, James T.; Lawrence, Scott D.; Kempen, John H.

    2015-01-01

    Purpose To characterize the risk and risk factors for intraocular pressure (IOP) elevation in pediatric non-infectious uveitis. Design Multi-center retrospective cohort study. Participants Nine hundred sixteen children (1593 eyes) uveitis followed between January 1978 through December 2007 at five academic uveitis centers in United States. Methods Medical records review by trained, certified experts. Main outcome measures Prevalence and incidence of IOP≥21 and ≥30mmHg and incidence of a rise in IOP by ≥10mmHg. To avoid under ascertainment, outcomes were counted as present when IOP-lowering therapies were in use. Results Initially 251 (15.8%) and 46 eyes (2.9%) had IOP≥21 and ≥30mmHg, respectively. Factors associated with presenting IOP elevation included age 6–12 years (versus other pediatric ages), prior cataract surgery (adjusted odds ratio≥21mmHg [aOR21]=2.42, P=0.01), pars plana vitrectomy (adjusted odds ratio≥30mmHg[aOR30]=11.1, P=0.03), duration of uveitis ≥6 months (aORs30 up to 11.8, Puveitis. Statistically significant risk factors include IOP elevation or use of IOP-lowering treatment in the contralateral eye and local corticosteroid use – that demonstrated a dose-and route of administration-dependent relationship. In contrast, use of immunosuppressive drug therapy did not increase such risk. Pediatric eyes with non-infectious uveitis should be followed closely for IOP elevation when strong risk factors such as the use of local corticosteroids and contralateral IOP elevation are present. PMID:26233626

  15. Idiopathic Intracranial Hypertension – Pathophysiology Based on Case Series

    Directory of Open Access Journals (Sweden)

    Ljubisavljević Srdjan

    2016-09-01

    Full Text Available According to the definition, idiopathic intracranial hypertension (IIH is a pathological state characterized by an increase in intracranial pressure; however, there are no obvious intracranial pathological processes. The pathophysiology of this disorder is not clear, although there are many reports related to it.

  16. Comparison of Intracranial Pressure and Pressure Reactivity Index Obtained Through Pressure Measurements in the Ventricle and in the Parenchyma During and Outside Cerebrospinal Fluid Drainage Episodes in a Manipulation-Free Patient Setting.

    Science.gov (United States)

    Klein, Samuel Patrick; Bruyninckx, Dominike; Callebaut, Ina; Depreitere, Bart

    2018-01-01

    We investigated the effect of cerebrospinal fluid (CSF) drainage on the intracranial pressure (ICP) signal measured in the parenchyma and the ventricle as well as the effect on the pressure reactivity index (PRx) calculated from both signals.  Ten patients were included in this prospective study. All patients received a parenchymal ICP sensor and an external ventricular drain (EVD) for CSF drainage. ICP signals (ICP-p and ICP-evd) were captured. Part of the study was a period of 90 min during which the patient was free from any manipulation, consisting of 30 min of drainage (O1), 30 min EVD closed (C) and 30 min of drainage (O2).  Mean ICP-evd and mean AMP-evd increased (3.03 and 0.46 mmHg) from O1 to C and decreased (2.12 and 0.43 mmHg) from C to O2. ICP-p and AMP-p changes were less pronounced (closing EVD: +0.81 mmHg/+0.22 mmHg; opening EVD: -0.22 mmHg/-0.05 mmHg). Mean difference between PRx-evd and PRx-p was 0.12 for O1, 0.02 for C and -0.02 for O2. The intraclass correlation coefficient for absolute agreement of single measures was 0.66 for O1, 0.77 for C and 0.69 for O2. Mean PRx differences demonstrated a significant difference between O1 versus C and O1 versus O2 but not between C versus O2.  Drainage of CSF reduces ICP magnitude and amplitude through the EVD. This effect was only marginal in parenchymal ICP measurements. In manipulation-free circumstances, agreement of PRx obtained through parenchymal and ventricular measurements was moderate to good, depending on the statistical method, and was not necessarily influenced by drainage.

  17. Turbulent burning characteristics of FACE-C gasoline and TPRF blend associated with the same RON at elevated pressures

    KAUST Repository

    Mannaa, Ossama; Brequigny, P.; Mounaim-Rousselle, C.; Foucher, F.; Chung, Suk-Ho; Roberts, William L.

    2018-01-01

    morphology induced by the simultaneous existences of different turbulent length scales and the susceptibility to develop cellular structures at elevated pressures (through the Darrieus-Landau instability). Measurements were performed in a well

  18. Visual Impairment and Intracranial Hypertension: An Emerging Spaceflight Risk

    Science.gov (United States)

    Taddeo, Terrance A.

    2010-01-01

    During recent long duration missions to the International Space Station (ISS) crewmembers have reported changes in visual acuity or visual field defects. Exams in the postflight period revealed changes to the visual system and elevated intracranial pressures. As a result, NASA Space Medicine has added a number of tests to be performed in the preflight, inflight and postflight periods for ISS and shuttle missions with the goal of determining the processes at work and any potential mitigation strategies. This discussion will acquaint you with the changes that NASA has made to its medical requirements in order to address the microgravity induced intracranial hypertension and associated visual changes. Key personnel have been assembled to provide you information on this topic. Educational Objectives: Provide an overview of the current Medical Operations requirements and the mitigation steps taken to operationally address the issue.

  19. Clinical analysis of modified trabeculectomy in glaucoma surgery with high elevated intraocular pressure

    Directory of Open Access Journals (Sweden)

    Cang-Xia Zhang

    2013-10-01

    Full Text Available AIM: To make a retrospective analysis of the clinical data of modified trabeculectomy in treating glaucoma surgery with high elevated intraocular pressure retrospectively and evaluate the effect of modified trabeculectomy.METHODS:One hundred acute angle-closure glaucoma patients(100 eyeswith persistent high intraocular pressure were divided into treatment group(45 eyesand control group(55 eyes. Patients in treatment group was treated with by trabeculectomy, while those in control group received modified trabeculectomy. The modified measures include stellate ganglion block preoperative, topical anesthesia and local anesthesia with 20g/L lidocaine cotton-piece, to make scleral flap with sclerotome, to release aqueous humor outflow slowly after paracentesis of anterior chamber, and using mydriatic and cycloplegic during and after surgery.RESULTS: The incidence of operation complicationin control group was lower than that in treatment group. The differences were statistically significant(Pt=9.1535, Pt=39.8010, Pt=11.3219, PCONCLUSION: The modified trabeculectomy applied in the treatment of glaucoma with persistent high intraocular pressure can not only save the visual function of connection part to a certain extent, but also reduce the incidence of serious complications. It can obtain better intraocular pressure, shorten the average hospitalization days, decrease the expenses and increase patients satisfaction.

  20. Preschool Children with Obstructive Sleep Apnea: The Beginnings of Elevated Blood Pressure?

    Science.gov (United States)

    Nisbet, Lauren C.; Yiallourou, Stephanie R.; Biggs, Sarah N.; Nixon, Gillian M.; Davey, Margot J.; Trinder, John A.; Walter, Lisa M.; Horne, Rosemary S. C.

    2013-01-01

    Study Objectives: In adults and older children, snoring and obstructive sleep apnea (OSA) are associated with elevated blood pressure (BP). However, BP has not been assessed in preschool children, the age of highest OSA prevalence. We aimed to assess overnight BP in preschool children with snoring and OSA using pulse transit time (PTT), an inverse continuous indicator of BP changes. Design: Overnight polysomnography including PTT. Children were grouped according to their obstructive apnea-hypopnea index (OAHI); control (no snoring, with OAHI of one event or less per hour), primary snoring (OAHI one event or less per hour), mild OSA (OAHI greater than one event to five events per hour) and moderate-severe OSA (OAHI more than five events per hour). Setting: Pediatric sleep laboratory. Patients: There were 128 clinically referred children (aged 3-5 years) and 35 nonsnoring community control children. Measurement and Results: PTT was averaged for each 30-sec epoch of rapid eye movement (REM) or nonrapid eye movement (NREM) sleep and normalized to each child's mean wake PTT. PTT during NREM was significantly higher than during REM sleep in all groups (P Biggs SN; Nixon GM; Davey MJ; Trinder JA; Walter LM; Horne RSC. Preschool children with obstructive sleep apnea: the beginnings of elevated blood pressure? SLEEP 2013;36(8):1219-1226. PMID:23904682

  1. Prevalence of elevated mean arterial pressure and how fitness moderates its association with BMI in youth.

    Science.gov (United States)

    Ogunleye, Ayodele A; Sandercock, Gavin R; Voss, Christine; Eisenmann, Joey C; Reed, Katharine

    2013-11-01

    Cardiorespiratory fitness is known to be cardioprotective and its association with the components of the metabolic syndrome in children is becoming clearer. The aim of the present study was to examine the extent to which cardiorespiratory fitness may offset the weight-related association with mean arterial pressure (MAP) in schoolchildren. Cross-sectional study. Schoolchildren from the East of England, U.K. A total of 5983 (48% females) schoolchildren, 10 to 16 years of age, had height, weight and blood pressure measured by standard procedures and cardiorespiratory fitness assessed by the 20 m shuttle-run test. Participants were classified as fit or unfit using internationally accepted fitness cut-off points; and as normal weight, overweight or obese based on BMI, again using international cut-off points. Age-adjusted ANCOVA was used to determine the main effects and interaction of fitness and BMI on MAP Z-score. Logistic regression models were used to estimate odds ratios of elevated MAP. Prevalence of elevated MAP in schoolchildren was 14.8% overall and 35.7% in those who were obese-unfit. Approximately 21% of participants were overweight and 5% obese, while 23% were classified as unfit. MAP generally increased across BMI categories and was higher in the aerobically unfit participants. Obese-fit males had lower MAP compared with obese-unfit males (P < 0.001); this trend was similar in females (P = 0.05). Increasing fitness level may have a positive impact on the weight-related elevations of MAP seen in obese and overweight schoolchildren.

  2. Apraclonidine versus brinzolamide-timolol combination to prevent intraocular pressure elevation after laser capsulotomy

    Directory of Open Access Journals (Sweden)

    Erkan Çelik

    2016-01-01

    Full Text Available AIM: To compare the efficacy of fixed combination of brinzolamide 1% and timolol 0.5%(FCBTwith apraclonidine 0.5%(APRAin preventing intraocular pressure(IOPelevations after neodymium: yttrium-aluminum-garnet(Nd:YAGlaser posterior capsulotomy.METHODS: This prospective randomized clinical study included 90 eyes of 90 consecutive patients who had Nd:YAG laser posterior capsulotomy for posterior capsule opacification(PCO. Patients were randomized to receive APRA(n=45or FCBT(n=45at 1h before laser surgery. A masked observer measured IOP by Goldmann applanation tonometry before the procedure and at 1, 2, 3, 24h and 7d after laser treatment. IOP outcome measures were grouped into the following categories: post laser IOP elevation of 5 to RESULTS:The mean IOP before surgery on the day of the procedure was 14.1±2.1 mm Hg in the APRA group and 13.2±2.1 mm Hg in the FCBT group. There was no statistically significant difference between the APRA and the FCBT groups of baseline IOPs measured(P=0.066. During the follow-up time, the mean IOP was lower in FCBT group, but this was not statistically significant. Six patients(13.3%in APRA group and 4(8.9%in FCBT group had IOP elevations of 5 to P=0.243. IOP elevations of 10 mm Hg or more occurred in 3 eyes(6.7%in the APRA group and 1 eyes(2.2%in the FCBT group; this was not statistically significant(P=0.542. CONCLUSION:Both of APRA and FCBT are effective for prevention and APRA is enough for most of routine cases. FCBT may be an option for the eyes those need more IOP reduction such as pre-existing glaucoma patients who are at higher risk for postoperative IOP elevations.

  3. Childhood obesity and elevated blood pressure in a rural population of northern Greece.

    Science.gov (United States)

    Mavrakanas, Thomas A; Konsoula, Georgia; Patsonis, Ioannis; Merkouris, Bodossakis P

    2009-01-01

    The objective of this study was to determine the prevalence of childhood obesity and elevated blood pressure (BP) in a rural population of northern Greece. In total, 572 schoolchildren between the age of 4 and 10 years were examined. Obesity was defined using three different standards: (1) body mass index (BMI) charts of the French society of Paediatrics (FR), selected because of the low cardiovascular risk profile and low prevalence of obesity in France; (2) United States BMI CDC charts (US), selected because of the high prevalence of childhood obesity in the USA; and the reference curves of the International Obesity Task Force (IOTF). Children with elevated BP were defined as BP > or = 95th percentile for age, gender and height, according to the Greek national charts. The prevalence of obesity for boys was 13.6% (IOTF), 23.7% (US) and 31.7% (FR); for girls 14.4% (IOTF), 21.1% (US) and 35.1% (FR). The prevalence of elevated BP was 7.9% (45 children). It was 5 to 6 times more common for obese than non-obese children to have elevated BP (relative risk of 5.2 to 6.2 and odds ratio 6.3 to 7.7). The results confirm the high prevalence of childhood obesity in Greece, in this study found to be more prevalent in rural than urban Greece. The IOTF criteria tend to underestimate obesity and may not be optimal for use in a primary clinical care setting where the approach is for health education and patient treatment, rather than purely epidemiological. The study also confirms a strong relationship between high BP and increased BMI.

  4. Guar Gum Stimulates Biogenic Sulfide Production at Elevated Pressures: Implications for Shale Gas Extraction.

    Science.gov (United States)

    Nixon, Sophie L; Walker, Leanne; Streets, Matthew D T; Eden, Bob; Boothman, Christopher; Taylor, Kevin G; Lloyd, Jonathan R

    2017-01-01

    Biogenic sulfide production is a common problem in the oil industry, and can lead to costly hydrocarbon processing and corrosion of extraction infrastructure. The same phenomenon has recently been identified in shale gas extraction by hydraulic fracturing, and organic additives in fracturing fluid have been hypothesized to stimulate this process. Constraining the relative effects of the numerous organic additives on microbial metabolism in situ is, however, extremely challenging. Using a bespoke bioreactor system we sought to assess the potential for guar gum, the most commonly used gelling agent in fracturing fluids, to stimulate biogenic sulfide production by sulfate-reducing microorganisms at elevated pressure. Two pressurized bioreactors were fed with either sulfate-amended freshwater medium, or low-sulfate natural surface water, in addition to guar gum (0.05 w/v%) and an inoculum of sulfate-reducing bacteria for a period of 77 days. Sulfide production was observed in both bioreactors, even when the sulfate concentration was low. Analysis of 16S rRNA gene sequences indicate that heterotrophic bacteria closely associated with the genera Brevundimonas and Acinetobacter became enriched early in the bioreactor experiments, followed by an increase in relative abundance of 16S rRNA genes associated with sulfate-reducing bacteria ( Desulfosporosinus and Desulfobacteraceae) at later time points. Results demonstrate that guar gum can stimulate acid- and sulfide-producing microorganisms at elevated pressure, and may have implications for the potential role in microbially induced corrosion during hydraulic fracturing operations. Key differences between experimental and in situ conditions are discussed, as well as additional sources of carbon and energy for biogenic sulfide production during shale gas extraction. Our laboratory approach can be tailored to better simulate deep subsurface conditions in order to probe the role of other fracturing fluid additives and downhole

  5. Guar Gum Stimulates Biogenic Sulfide Production at Elevated Pressures: Implications for Shale Gas Extraction

    Science.gov (United States)

    Nixon, Sophie L.; Walker, Leanne; Streets, Matthew D. T.; Eden, Bob; Boothman, Christopher; Taylor, Kevin G.; Lloyd, Jonathan R.

    2017-01-01

    Biogenic sulfide production is a common problem in the oil industry, and can lead to costly hydrocarbon processing and corrosion of extraction infrastructure. The same phenomenon has recently been identified in shale gas extraction by hydraulic fracturing, and organic additives in fracturing fluid have been hypothesized to stimulate this process. Constraining the relative effects of the numerous organic additives on microbial metabolism in situ is, however, extremely challenging. Using a bespoke bioreactor system we sought to assess the potential for guar gum, the most commonly used gelling agent in fracturing fluids, to stimulate biogenic sulfide production by sulfate-reducing microorganisms at elevated pressure. Two pressurized bioreactors were fed with either sulfate-amended freshwater medium, or low-sulfate natural surface water, in addition to guar gum (0.05 w/v%) and an inoculum of sulfate-reducing bacteria for a period of 77 days. Sulfide production was observed in both bioreactors, even when the sulfate concentration was low. Analysis of 16S rRNA gene sequences indicate that heterotrophic bacteria closely associated with the genera Brevundimonas and Acinetobacter became enriched early in the bioreactor experiments, followed by an increase in relative abundance of 16S rRNA genes associated with sulfate-reducing bacteria (Desulfosporosinus and Desulfobacteraceae) at later time points. Results demonstrate that guar gum can stimulate acid- and sulfide-producing microorganisms at elevated pressure, and may have implications for the potential role in microbially induced corrosion during hydraulic fracturing operations. Key differences between experimental and in situ conditions are discussed, as well as additional sources of carbon and energy for biogenic sulfide production during shale gas extraction. Our laboratory approach can be tailored to better simulate deep subsurface conditions in order to probe the role of other fracturing fluid additives and downhole

  6. Contribution of TRPV1 to microglia-derived IL-6 and NFkappaB translocation with elevated hydrostatic pressure.

    Science.gov (United States)

    Sappington, Rebecca M; Calkins, David J

    2008-07-01

    The authors investigated the contributions of the transient receptor potential vanilloid-1 receptor (TRPV1) and Ca(2+) to microglial IL-6 and nuclear factor kappa B (NFkappaB) translocation with elevated hydrostatic pressure. The authors first examined IL-6 colocalization with the microglia marker Iba-1 in the DBA/2 mouse model of glaucoma to establish relevance. They isolated microglia from rat retina and maintained them at ambient or elevated (+70 mm Hg) hydrostatic pressure in vitro and used ELISA and immunocytochemistry to measure changes in the IL-6 concentration and NFkappaB translocation induced by the Ca(2+) chelator EGTA, the broad-spectrum Ca(2+) channel inhibitor ruthenium red, and the TRPV1 antagonist iodo-resiniferatoxin (I-RTX). They applied the Ca(2+) dye Fluo-4 AM to measure changes in intracellular Ca(2+) at elevated pressure induced by I-RTX and confirmed TRPV1 expression in microglia using PCR and immunocytochemistry. In DBA/2 retina, elevated intraocular pressure increased microglial IL-6 in the ganglion cell layer. Elevated hydrostatic pressure (24 hours) increased microglial IL-6 release, cytosolic NFkappaB, and NFkappaB translocation in vitro. These effects were reduced substantially by EGTA and ruthenium red. Antagonism of TRPV1 in microglia partially inhibited pressure-induced increases in IL-6 release and NFkappaB translocation. Brief elevated pressure (1 hour) induced a significant increase in microglial intracellular Ca(2+) that was partially attenuated by TRPV1 antagonism. Elevated pressure induces an influx of extracellular Ca(2+) in retinal microglia that precedes the activation of NFkappaB and the subsequent production and release of IL-6 and is at least partially dependent on the activation of TRPV1 and other ruthenium red-sensitive channels.

  7. Detection of elevated pulmonary capillary wedge pressure in elderly patients with various cardiac disorders by the Valsalva manoeuvre.

    NARCIS (Netherlands)

    Remmen, J.J.; Aengevaeren, W.R.M.; Verheugt, F.W.A.; Jansen, R.W.M.M.

    2006-01-01

    In the present study, we assessed whether elevated (> or =15 mmHg) PCWP (pulmonary capillary wedge pressure) can be detected using the blood pressure response to the Valsalva manoeuvre in a group of elderly patients with various cardiac disorders, including atrial fibrillation and valvular heart

  8. Barley seed ageing: genetics behind the dry elevated pressure of oxygen ageing and moist controlled deterioration

    Directory of Open Access Journals (Sweden)

    Manuela eNagel

    2016-03-01

    Full Text Available Experimental seed ageing approaches intend to mimic seed deterioration processes to achieve a storage interval reduction. Common methods apply higher seed moisture levels and temperatures. In contrast, the elevated partial pressure of oxygen (EPPO approach treats dry seed stored at ambient temperatures with high oxygen pressure. To analyse the genetic background of seed longevity and the effects of seed ageing under dry conditions, the EPPO approach was applied to the progeny of the Oregon Wolfe Barley (OWB mapping population. In comparison to a non-treated control and a control high-pressure nitrogen treatment, EPPO stored seeds showed typical symptoms of ageing with a significant reduction of normal seedlings, slower germination, and less total germination. Thereby, the parent Dom (OWB-D, carrying dominant alleles, is more sensitive to ageing in comparison to the population mean and in most cases to the parent Rec (OWB-R, carrying recessive alleles. Quantitative trait locus (QTL analyses using 2,832 markers revealed 65 QTLs, including two major loci for seed vigor on 2H and 7H. QTLs for EPPO tolerance were detected on 3H, 4H, and 5H. An applied controlled deterioration (CD treatment (aged at higher moisture level and temperature revealed a tolerance QTL on 5H, indicating that the mechanism of seed deterioration differs in part between EPPO or CD conditions.

  9. Numerical Study of Pollutant Emissions in a Jet Stirred Reactor under Elevated Pressure Lean Premixed Conditions

    Directory of Open Access Journals (Sweden)

    Karim Mazaheri

    2016-01-01

    Full Text Available Numerical study of pollutant emissions (NO and CO in a Jet Stirred Reactor (JSR combustor for methane oxidation under Elevated Pressure Lean Premixed (EPLP conditions is presented. A Detailed Flow-field Simplified Chemistry (DFSC method, a low computational cost method, is employed for predicting NO and CO concentrations. Reynolds Averaged Navier Stokes (RANS equations with species transport equations are solved. Improved-coefficient five-step global mechanisms derived from a new evolutionary-based approach were taken as combustion kinetics. For modeling turbulent flow field, Reynolds Stress Model (RSM, and for turbulence chemistry interactions, finite rate-Eddy dissipation model are employed. Effects of pressure (3, 6.5 bars and inlet temperature (408–573 K over a range of residence time (1.49–3.97 ms are numerically examined. A good agreement between the numerical and experimental distribution of NO and CO was found. The effect of decreasing the operating pressure on NO generation is much more than the effect of increase in the inlet temperature.

  10. Modeling carbon dioxide sequestration in saline aquifers: Significance of elevated pressures and salinities

    International Nuclear Information System (INIS)

    Allen, D.E.; Strazisar, B.R.; Soong, Y.; Hedges, S.W.

    2005-01-01

    The ultimate capacity of saline formations to sequester carbon dioxide by solubility and mineral trapping must be determined by simulating sequestration with geochemical models. These models, however, are only as reliable as the data and reaction scheme on which they are based. Several models have been used to make estimates of carbon dioxide solubility and mineral formation as a function of pressure and fluid composition. Intercomparison of modeling results indicates that failure to adjust all equilibrium constants to account for elevated carbon dioxide pressures results in significant errors in both solubility and mineral formation estimates. Absence of experimental data at high carbon dioxide pressures and high salinities make verification of model results difficult. Results indicate standalone solubility models that do not take mineral reactions into account will underestimate the total capacity of aquifers to sequester carbon dioxide in the long term through enhanced solubility and mineral trapping mechanisms. Overall, it is difficult to confidently predict the ultimate sequestration capacity of deep saline aquifers using geochemical models. (author)

  11. Study of creep collapse of tubes subject to external pressure at elevated temperature

    International Nuclear Information System (INIS)

    Takikawa, N.

    1982-01-01

    Intermediate heat exchanger (IHX) tubes of VHTR form the boundary between the primary and secondary coolants of the reactor. The tubes are subject to external pressures at a postulated secondary coolant depressurization accident, which might lead to creep collapse. Therefore, it is necessary to ensure the integrity against creep collapse by analysis. The objective of this work is to study a simplified analytical method for predicting collapse time of a curved tube subjected to an external pressure. The study is made based on the comparison of experimental collapse time of curved and straight tubes. Creep collapse tests were conducted under an elevated temperature and an external pressure. Test results showed that curved tubes had longer collapse time than straight tubes with the same cross sectional ovality. The simplified analytical method for a curved tube is proposed in this report, which is to compute collapse time of a straight tube with the same ovality. And in this method the computed time is considered as collapse time of the curved tube. The above test results show that this simplified method gives the conservative collapse time. And it is confirmed by additional IHX tube tests that the method is applicable to creep collapse analysis of IHX tubes

  12. Experimental apparatus with full optical access for combustion experiments with laminar flames from a single circular nozzle at elevated pressures.

    Science.gov (United States)

    Joo, Peter H; Gao, Jinlong; Li, Zhongshan; Aldén, Marcus

    2015-03-01

    The design and features of a high pressure chamber and burner that is suitable for combustion experiments at elevated pressures are presented. The high pressure combustion apparatus utilizes a high pressure burner that is comprised of a chamber burner module and an easily accessible interchangeable burner module to add to its flexibility. The burner is well suited to study both premixed and non-premixed flames. The optical access to the chamber is provided through four viewports for direct visual observations and optical-based diagnostic techniques. Auxiliary features include numerous access ports and electrical connections and as a result, the combustion apparatus is also suitable to work with plasmas and liquid fuels. Images of methane flames at elevated pressures up to 25 atm and preliminary results of optical-based measurements demonstrate the suitability of the high pressure experimental apparatus for combustion experiments.

  13. Rationale and Design of the Reduce Elevated Left Atrial Pressure in Patients With Heart Failure (Reduce LAP-HF) Trial

    DEFF Research Database (Denmark)

    Hasenfuss, Gerd; Gustafsson, Finn; Kaye, David

    2015-01-01

    OBJECTIVE: Heart failure with preserved ejection fraction (HFpEF) is characterized by elevated left atrial pressure during rest and/or exercise. The Reduce LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial will evaluate the safety and performance of the Interatrial...... Shunt Device (IASD) System II, designed to directly reduce elevated left atrial pressure, in patients with HFpEF. METHODS: The Reduce LAP-HF Trial is a prospective, nonrandomized, open-label trial to evaluate a novel device that creates a small permanent shunt at the level of the atria. A minimum of 60...... patients with ejection fraction ≥40% and New York Heart Association functional class III or IV heart failure with a pulmonary capillary wedge pressure (PCWP) ≥15 mm Hg at rest or ≥25 mm Hg during supine bike exercise will be implanted with an IASD System II, and followed for 6 months to assess the primary...

  14. Invasive and Ultrasound Based Monitoring of the Intracranial Pressure in an Experimental Model of Epidural Hematoma Progressing towards Brain Tamponade on Rabbits

    Directory of Open Access Journals (Sweden)

    Konstantinos Kasapas

    2014-01-01

    Full Text Available Introduction. An experimental epidural hematoma model was used to study the relation of ultrasound indices, namely, transcranial color-coded-Doppler (TCCD derived pulsatility index (PI, optic nerve sheath diameter (ONSD, and pupil constriction velocity (V which was derived from a consensual sonographic pupillary light reflex (PLR test with invasive intracranial pressure (ICP measurements. Material and Methods. Twenty rabbits participated in the study. An intraparenchymal ICP catheter and a 5F Swan-Ganz catheter (SG for the hematoma reproduction were used. We successively introduced 0.1 mL increments of autologous blood into the SG until the Cushing reaction occurred. Synchronous ICP and ultrasound measurements were performed accordingly. Results. A constant increase of PI and ONSD and a decrease of V values were observed with increased ICP values. The relationship between the ultrasound variables and ICP was exponential; thus curved prediction equations of ICP were used. PI, ONSD, and V were significantly correlated with ICP (r2=0.84±0.076, r2=0.62±0.119, and r2=0.78±0.09, resp. (all P<0.001. Conclusion. Although statistically significant prediction models of ICP were derived from ultrasound indices, the exponential relationship between the parameters underpins that results should be interpreted with caution and in the current experimental context.

  15. Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

    OpenAIRE

    Chintalapudi, Sumana R.; Maria, Doaa; Di Wang, Xiang; Bailey, Jessica N. Cooke; Hysi, Pirro G.; Wiggs, Janey L.; Williams, Robert W.; Jablonski, Monica M.

    2017-01-01

    textabstractGlaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, ...

  16. Syphilis mimicking idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Yri, Hanne; Wegener, Marianne; Jensen, Rigmor

    2011-01-01

    Idiopathic intracranial hypertension (IIH) is a condition of yet unknown aetiology affecting predominantly obese females of childbearing age. IIH is a diagnosis of exclusion as raised cerebrospinal fluid pressure may occur secondary to numerous other medical conditions. An atypical phenotype...... or an atypical disease course should alert the physician to reevaluate a presumed IIH-diagnosis. The authors report a case of a 32-year-old non-obese male with intracranial hypertension, secondary to a syphilitic central nervous system infection, initially misdiagnosed as being idiopathic. Upon relevant...

  17. A microcatalytic flow reactor for the study of heterogeneous catalytic reactions at elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Belyi, A S; Fomichev, Yu V; Duplyakin, V K; Alfeev, V S

    1977-07-01

    A microcatalytic flow reactor for the study of heterogeneous catalytic reactions at elevated pressures (i.e., up to 40 atm) and nearly isothermal conditions up to 600/sup 0/C was designed for the conversion of small quantities of petrochemical feeds or feed mixtures at uniform, controllable flow rates of 0.5-5.0 cc/hr, for direct gas-chromatographic analysis of product samples at the reactor outlet, and for continuous monitoring of the degree of conversion in processes that evolve or absorb hydrogen. The device includes a feed injection system with a unique sealing feature that ensures a constant flow of liquid from a feed buret under positive displacement by a counterweight piston at very low rates into a tubular reactor of the perfect mixing type, a highly efficient vaporizer-mixer, and a two-channel sampler leading to the chromatograph. The apparatus has proved reliable, accurate, and convenient in two years of regular use. Diagrams.

  18. Temporal evolution of intraocular pressure elevation after pupillary dilation in pigment dispersion syndrome.

    Science.gov (United States)

    Jewelewicz, Daniel A; Radcliffe, Nathan M; Liebmann, Jeffrey; Ritch, Robert

    2009-03-01

    To report 4 patients with pigment dispersion syndrome (PDS) who had delayed intraocular pressure (IOP) spikes after pharmacologic pupillary dilation. Four patients with a diagnosis of PDS with documented IOP spike after pharmacologic pupillary dilation were included. Study patients were examined before and after pupillary dilation. The amount of pigment present in the anterior chamber and the IOP were measured at hourly intervals. Although maximal pigment liberation occurred immediately after maximal dilation, the IOP continued to elevate for at least 1.5 hours. The increase in IOP after pupillary dilation may not occur simultaneously with maximal pigment liberation but may follow it after the pigment has settled out of the anterior chamber. This has implications for monitoring patients with PDS after dilation to detect and treat rises in IOP.

  19. Effects of Weather and Heliophysical Conditions on Emergency Ambulance Calls for Elevated Arterial Blood Pressure

    Directory of Open Access Journals (Sweden)

    Jone Vencloviene

    2015-02-01

    Full Text Available We hypothesized that weather and space weather conditions were associated with the exacerbation of essential hypertension. The study was conducted during 2009–2010 in the city of Kaunas, Lithuania. We analyzed 13,475 cards from emergency ambulance calls (EACs, in which the conditions for the emergency calls were made coded I.10–I.15. The Kaunas Weather Station provided daily records of air temperature (T, wind speed (WS, relative humidity, and barometric pressure (BP. We evaluated the associations between daily weather variables and daily number of EACs by applying a multivariate Poisson regression. Unfavorable heliophysical conditions (two days after the active-stormy geomagnetic field or the days with solar WS > 600 km/s increased the daily number of elevated arterial blood pressure (EABP by 12% (RR = 1.12; 95% confidence interval (CI 1.04–1.21; and WS ≥ 3.5 knots during days of T < 1.5 °C and T ≥ 12.5 °C by 8% (RR = 1.08; CI 1.04–1.12. An increase of T by 10 °C and an elevation of BP two days after by 10 hPa were associated with a decrease in RR by 3%. An additional effect of T was detected during days of T ≥ 17.5 °C only in females. Women and patients with grade III arterial hypertension at the time of the ambulance call were more sensitive to weather conditions. These results may help in the understanding of the population’s sensitivity to different weather conditions.

  20. Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

    DEFF Research Database (Denmark)

    Hvidt, Kristian N; Olsen, Michael H; Holm, Jens-Christian

    2014-01-01

    BACKGROUND: Insulin resistance has been related to elevated blood pressure (BP) in obese children and may adversely affect the vasculature by arterial stiffening. The objective was to investigate whether daytime and nighttime BP were elevated and related to insulin resistance and arterial stiffness...... in obese children and adolescents. METHODS: Ninety-two obese patients aged 10-18 years were compared with 49 healthy control individuals. Insulin resistance was measured as the homeostatic assessment model (HOMA), and arterial stiffness was measured as carotid-femoral pulse wave velocity (cfPWV). RESULTS......: Mean ± SD daytime systolic BP (SBP) (obese: 125±8.3mm Hg; control: 121±10.1mm Hg; P = 0.03) and nighttime SBP (obese: 108±10.7mm Hg; control: 102±8.2mm Hg; P = 0.0001) were higher in the obese group when compared with the control group. No difference was found in daytime diastolic BP (DBP), whereas...

  1. Mechanisms of sympathetic activation and blood pressure elevation by intermittent hypoxia.

    Science.gov (United States)

    Prabhakar, Nanduri R; Kumar, Ganesh K

    2010-11-30

    Sleep disordered breathing with recurrent apneas is one of the most frequently encountered breathing disorder in adult humans and preterm infants. Recurrent apnea patients exhibit several co-morbidities including hypertension and persistent sympathetic activation. Intermittent hypoxia (IH) resulting from apneas appears to be the primary stimulus for evoking autonomic changes. The purpose of this article is to briefly review the effects of IH on chemo- and baro-reflexes and circulating vasoactive hormones and their contribution to sympathetic activation and blood pressures. Sleep apnea patients and IH-treated rodents exhibit exaggerated arterial chemo-reflex. Studies on rodent models demonstrated that IH leads to hyperactive carotid body response to hypoxia. On the other hand, baro-reflex function is attenuated in patients with sleep apnea and in IH-treated rodents. Circulating vasoactive hormone levels are elevated in sleep apnea patients and in rodent models of IH. Thus, persistent sympathetic activation and hypertension associated with sleep apneas seems to be due to a combination of altered chemo- and baro-reflexes resulting in sympathetic activation and action of elevated circulating levels of vasoactive hormones on vasculature. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Tobacco smoking strengthens the association of elevated blood pressure with arterial stiffness: the Bogalusa Heart Study.

    Science.gov (United States)

    Yun, Miaoying; Li, Shengxu; Sun, Dianjianyi; Ge, Shaoqing; Lai, Chin-Chih; Fernandez, Camilo; Chen, Wei; Srinivasan, Sathanur R; Berenson, Gerald S

    2015-02-01

    The study assessed the hypothesis that smoking strengthens the association of adult arterial stiffness with long-term cumulative burden of blood pressure (BP) from childhood to adulthood. Tobacco smoking and elevated BPs are important risk factors of vascular stiffness. However, the synergistic effect of these two risk factors is not well established, especially for the long-term burden of elevated BP since childhood. The study cohort consisted of 945 adults (661 whites and 284 blacks, aged 24-43 years) who have BP measured 4-15 times since childhood (aged 4-17 years) in Bogalusa, Louisiana. The adult arterial stiffness was measured as aorta-femoral pulse wave velocity (afPWV); the total area under the curve (AUC) and incremental AUC were used as a measure of long-term burden and trends of BP, respectively. Increased adult afPWV was significantly associated with higher adulthood (P AUC (P AUC (P AUC (P = 0.007) were significantly greater among the current smokers than among the nonsmokers. DBP showed a similar pattern regarding the smoking-BP interaction on afPWV. These results, by showing the synergistic effect of tobacco smoking and long-term BP measures from childhood to adulthood on arterial stiffening process, underscore the importance of undertaking preventive strategies early in life and smoking behavior control.

  3. The elevated temperature and thermal shock fracture toughnesses of nuclear pressure vessel steel

    International Nuclear Information System (INIS)

    Hirano, Kazumi; Kobayashi, Hideo; Nakazawa, Hajime; Nara, Atsushi.

    1979-01-01

    Thermal shock experiments were conducted on nuclear pressure vessel steel A533 Grade B Class 1. Elastic-plastic fracture toughness tests were carried out within the same high temperature range of the thermal shock experiment and the relation between stretched zone width, SZW and J-integral was clarified. An elastic-plastic thermal shock fracture toughness value. J sub(tsc) was evaluated from a critical value of stretched zone width, SZW sub(tsc) at the initiation of thermal shock fracture by using the relation between SZW and J. The J sub(tsc) value was compared with elastic-plastic fracture toughness values, J sub( ic), and the difference between the J sub(tsc) and J sub( ic) values was discussed. The results obtained are summarized as follows; (1) The relation between SZW and J before the initiation of stable crack growth in fracture toughness test at a high temperature can be expressed by the following equation regardless of test temperature, SZW = 95(J/E), where E is Young's modulus. (2) Elevated temperature fracture toughness values ranging from room temperature to 400 0 C are nearly constant regardless of test temperature. It is confirmed that upper shelf fracture toughness exists. (3) Thermal shock fracture toughness is smaller than elevated temperature fracture toughness within the same high temperature range of thermal shock experiment. (author)

  4. Effects of weather and heliophysical conditions on emergency ambulance calls for elevated arterial blood pressure.

    Science.gov (United States)

    Vencloviene, Jone; Babarskiene, Ruta M; Dobozinskas, Paulius; Sakalyte, Gintare; Lopatiene, Kristina; Mikelionis, Nerijus

    2015-02-27

    We hypothesized that weather and space weather conditions were associated with the exacerbation of essential hypertension. The study was conducted during 2009-2010 in the city of Kaunas, Lithuania. We analyzed 13,475 cards from emergency ambulance calls (EACs), in which the conditions for the emergency calls were made coded I.10-I.15. The Kaunas Weather Station provided daily records of air temperature (T), wind speed (WS), relative humidity, and barometric pressure (BP). We evaluated the associations between daily weather variables and daily number of EACs by applying a multivariate Poisson regression. Unfavorable heliophysical conditions (two days after the active-stormy geomagnetic field or the days with solar WS>600 km/s) increased the daily number of elevated arterial blood pressure (EABP) by 12% (RR=1.12; 95% confidence interval (CI) 1.04-1.21); and WS≥3.5 knots during days of Tweather conditions. These results may help in the understanding of the population's sensitivity to different weather conditions.

  5. Effects of gap and elevated pressure on ethanol reforming in a non-thermal plasma reactor

    International Nuclear Information System (INIS)

    Hoang, Trung Q; Zhu Xinli; Lobban, Lance L; Mallinson, Richard G

    2011-01-01

    Production of hydrogen for fuel cell vehicles, mobile power generators and for hydrogen-enhanced combustion from ethanol is demonstrated using energy-efficient non-thermal plasma reforming. A tubular reactor with a multipoint electrode system operated in pulsed mode was used. Complete conversion can be achieved with high selectivity (based on ethanol) of H 2 and CO of 111% and 78%, respectively, at atmospheric pressure. An elevated pressure of 15 psig shows improvement of selectivity of H 2 and CO to 120% and 87%, with a significant reduction of C 2 H x side products. H 2 selectivity increased to 127% when a high ratio (29.2) of water-to-ethanol feed was used. Increasing CO 2 selectivity is observed at higher water-to-ethanol ratios indicating that the water gas shift reaction occurs. A higher productivity and lower C 2 H x products were observed at larger gas gaps. The highest overall energy efficiency achieved, including electrical power consumption, was 82% for all products or 66% for H 2 only.

  6. Experimental strength evaluation of cylinders with a flat head subjected to internal pressure at elevated temperature

    International Nuclear Information System (INIS)

    Suzuki, Mitsuru; Makino, Yutaka

    1978-01-01

    The experiments using component test models such as a cylinder with a flat head and F.E.M. elastic analyses to investigate the secondary stress, peak stress and creep-fatigue interaction effect are described. The comparison of uniaxial stress with multiaxial stress about deformation and strength at elevated temperatures are also described here. The results of experiments and analysis are summarized as follows: (1) The maximum stress as the equivalent stress is the most suitable for the prediction of the creep failure life of cylinders subjected to internal pressure using the uniaxial creep test results. And the Mises's equivalent stress is the suitable for this prediction using the data of the onset of the uniaxial tertiary creep. (2) In the creep characteristics of the cylinder there, is no tertiary creep stage, and the rupture elongation of the cylinder accords with the elongation of the onset of the uniaxial tertiary creep. (3) It was recognized that the secondary stress occurred at the corner of the cylinder with a flat head has a little effect on creep and creep-fatigue life. (4) The life reduction effect due to the creep-fatigue interaction around the corner was recognized by the linear damage rule and compared with the value of Code Case 1592. (5) A difference of failure modes by imposed conditions for vessel with the size-discontinuity section was recognized by the cyclic internal pressure tests with hold time. (author)

  7. Simultaneous monitoring of static and dynamic intracranial pressure parameters from two separate sensors in patients with cerebral bleeds: comparison of findings.

    Science.gov (United States)

    Eide, Per Kristian; Holm, Sverre; Sorteberg, Wilhelm

    2012-09-07

    We recently reported that in an experimental setting the zero pressure level of solid intracranial pressure (ICP) sensors can be altered by electrostatics discharges. Changes in the zero pressure level would alter the ICP level (mean ICP); whether spontaneous changes in mean ICP happen in clinical settings is not known. This can be addressed by comparing the ICP parameters level and waveform of simultaneous ICP signals. To this end, we retrieved our recordings in patients with cerebral bleeds wherein the ICP had been recorded simultaneously from two different sensors. During a time period of 10 years, 17 patients with cerebral bleeds were monitored with two ICP sensors simultaneously; sensor 1 was always a solid sensor while Sensor 2 was a solid -, a fluid - or an air-pouch sensor. The simultaneous signals were analyzed with automatic identification of the cardiac induced ICP waves. The output was determined in consecutive 6-s time windows, both with regard to the static parameter mean ICP and the dynamic parameters (mean wave amplitude, MWA, and mean wave rise time, MWRT). Differences in mean ICP, MWA and MWRT between the two sensors were determined. Transfer functions between the sensors were determined to evaluate how sensors reproduce the ICP waveform. Comparing findings in two solid sensors disclosed major differences in mean ICP in 2 of 5 patients (40%), despite marginal differences in MWA, MWRT, and linear phase magnitude and phase. Qualitative assessment of trend plots of mean ICP and MWA revealed shifts and drifts of mean ICP in the clinical setting. The transfer function analysis comparing the solid sensor with either the fluid or air-pouch sensors revealed more variable transfer function magnitude and greater differences in the ICP waveform derived indices. Simultaneous monitoring of ICP using two solid sensors may show marked differences in static ICP but close to identity in dynamic ICP waveforms. This indicates that shifts in ICP baseline pressure

  8. Simultaneous monitoring of static and dynamic intracranial pressure parameters from two separate sensors in patients with cerebral bleeds: comparison of findings

    Directory of Open Access Journals (Sweden)

    Eide Per

    2012-09-01

    Full Text Available Abstract Background We recently reported that in an experimental setting the zero pressure level of solid intracranial pressure (ICP sensors can be altered by electrostatics discharges. Changes in the zero pressure level would alter the ICP level (mean ICP; whether spontaneous changes in mean ICP happen in clinical settings is not known. This can be addressed by comparing the ICP parameters level and waveform of simultaneous ICP signals. To this end, we retrieved our recordings in patients with cerebral bleeds wherein the ICP had been recorded simultaneously from two different sensors. Materials and Methods: During a time period of 10 years, 17 patients with cerebral bleeds were monitored with two ICP sensors simultaneously; sensor 1 was always a solid sensor while Sensor 2 was a solid -, a fluid - or an air-pouch sensor. The simultaneous signals were analyzed with automatic identification of the cardiac induced ICP waves. The output was determined in consecutive 6-s time windows, both with regard to the static parameter mean ICP and the dynamic parameters (mean wave amplitude, MWA, and mean wave rise time, MWRT. Differences in mean ICP, MWA and MWRT between the two sensors were determined. Transfer functions between the sensors were determined to evaluate how sensors reproduce the ICP waveform. Results Comparing findings in two solid sensors disclosed major differences in mean ICP in 2 of 5 patients (40%, despite marginal differences in MWA, MWRT, and linear phase magnitude and phase. Qualitative assessment of trend plots of mean ICP and MWA revealed shifts and drifts of mean ICP in the clinical setting. The transfer function analysis comparing the solid sensor with either the fluid or air-pouch sensors revealed more variable transfer function magnitude and greater differences in the ICP waveform derived indices. Conclusions Simultaneous monitoring of ICP using two solid sensors may show marked differences in static ICP but close to identity

  9. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature

    OpenAIRE

    Liu Gang; Wang Jianlong; Dang Kexin; Yuan Shijian

    2015-01-01

    High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were ...

  10. Macroglia-derived thrombospondin 2 regulates alterations of presynaptic proteins of retinal neurons following elevated hydrostatic pressure.

    Science.gov (United States)

    Wang, Shuchao; Hu, Tu; Wang, Zhen; Li, Na; Zhou, Lihong; Liao, Lvshuang; Wang, Mi; Liao, Libin; Wang, Hui; Zeng, Leping; Fan, Chunling; Zhou, Hongkang; Xiong, Kun; Huang, Jufang; Chen, Dan

    2017-01-01

    Many studies on retinal injury and repair following elevated intraocular pressure suggest that the survival ratio of retinal neurons has been improved by various measures. However, the visual function recovery is far lower than expected. The homeostasis of retinal synapses in the visual signal pathway is the key structural basis for the delivery of visual signals. Our previous studies found that complicated changes in the synaptic structure between retinal neurons occurred much earlier than obvious degeneration of retinal ganglion cells in rat retinae. The lack of consideration of these earlier retinal synaptic changes in the rescue strategy may be partly responsible for the limited visual function recovery with the types of protective methods for retinal neurons used following elevated intraocular pressure. Thus, research on the modulatory mechanisms of the synaptic changes after elevated intraocular pressure injury may give new light to visual function rescue. In this study, we found that thrombospondin 2, an important regulator of synaptogenesis in central nervous system development, was distributed in retinal macroglia cells, and its receptor α2δ-1 was in retinal neurons. Cell cultures including mixed retinal macroglia cells/neuron cultures and retinal neuron cultures were exposed to elevated hydrostatic pressure for 2 h. The expression levels of glial fibrillary acidic protein (the marker of activated macroglia cells), thrombospondin 2, α2δ-1 and presynaptic proteins were increased following elevated hydrostatic pressure in mixed cultures, but the expression levels of postsynaptic proteins were not changed. SiRNA targeting thrombospondin 2 could decrease the upregulation of presynaptic proteins induced by the elevated hydrostatic pressure. However, in retinal neuron cultures, elevated hydrostatic pressure did not affect the expression of presynaptic or postsynaptic proteins. Rather, the retinal neuron cultures with added recombinant thrombospondin 2

  11. Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure

    Directory of Open Access Journals (Sweden)

    Nusinowitz Steven

    2001-11-01

    Full Text Available Abstract Background Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP. In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. Results Bmp4+/- mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. Conclusions We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4+/- mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes.

  12. Effects of selected thermophilic microorganisms on crude oils at elevated temperatures and pressures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Premuzic, E.T.; Lin, M.S.

    1995-07-01

    During the past several years, a considerable amount of work has been carried out showing that microbially enhanced oil recovery (MEOR) is promising and the resulting biotechnology may be deliverable. At the Brookhaven National Laboratory (BNL), systematic studies have been conducted which dealt with the effects of thermophilic and thermoadapted bacteria on the chemical and physical properties of selected types of crude oils at elevated temperatures and pressures. Particular attention was paid to heavy crude oils from Venezuela, California, Alabama, Arkansas, Wyoming, Alaska, and other oil producing areas. Current studies indicate that during the biotreatment several chemical and physical properties of crude oils are affected. The oils are (1) emulsified; (2) acidified; (3) there is a qualitative and quantitative change in light and heavy fractions of the crudes; (4) there are chemical changes in fractions containing sulfur compounds; (5) there is an apparent reduction in the concentration of trace metals; (6) the qualitative and quantitative changes appear to be microbial species dependent; and (7) there is a distinction between {open_quotes}biodegraded{close_quotes} and {open_quotes}biotreated{close_quotes} oils. Preliminary results indicate the introduced microorganisms may become the dominant species in the bioconversion of oils. These studies also indicate the biochemical interactions between crude oils and microorganisms follow distinct trends, characterized by a group of chemical markers. Core-flooding experiments have shown significant additional crude oil recoveries are achievable with thermophilic microorganisms at elevated temperatures similar to those found in oil reservoirs. In addition, the biochemical treatment of crude oils has technological applications in downstream processing of crude oils such as in upgrading of low grade oils and the production of hydrocarbon based detergents.

  13. Elevated pressure, a novel cancer therapeutic tool for sensitizing cisplatin-mediated apoptosis in A549

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sangnam [Cellular and Developmental Biology, Division of Biomedical Science, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Department of Preventive Medicine and Medical Research Center for Environmental Toxico-Genomics and Proteomics, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Kim, Yanghee [Department of Preventive Medicine and Medical Research Center for Environmental Toxico-Genomics and Proteomics, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Kim, Joonhee [Cellular and Developmental Biology, Division of Biomedical Science, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Department of Preventive Medicine and Medical Research Center for Environmental Toxico-Genomics and Proteomics, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Kwon, Daeho [Department of Preventive Medicine and Medical Research Center for Environmental Toxico-Genomics and Proteomics, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Lee, Eunil, E-mail: eunil@korea.ac.kr [Cellular and Developmental Biology, Division of Biomedical Science, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Department of Preventive Medicine and Medical Research Center for Environmental Toxico-Genomics and Proteomics, College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of)

    2010-08-13

    Research highlights: {yields} Sensitized apoptosis in cancer cells stimulated by EP precondition with p53 dependence. {yields} EP attenuates several CDDP-resistance mechanisms. {yields} No harmful effect of EP on normal fibroblasts. -- Abstract: Intensive cancer therapy strategies have thus far focused on sensitizing cancer cells to anticancer drug-mediated apoptosis to overcome drug resistance, and this strategy has led to more effective cancer therapeutics. Cisplatin (cis-diamminedichloroplatinum(II), CDDP) is an effective anticancer drug used to treat many types of cancer, including non-small cell lung carcinoma (NSCLC), and can be used in combination with various chemicals to enhance cancer cell apoptosis. Here, we introduce the use of elevated pressure (EP) in combination with CDDP for cancer treatment and explore the effects of EP on CDDP-mediated apoptosis in NSCLC cells. Our findings demonstrate that preconditioning NSCLC cells with EP sensitizes cells for CDDP-induced apoptosis. Enhanced apoptosis was dependent on p53 and HO-1 expression, and was associated with increased DNA damage and down-regulation of genes involved in nucleotide excision repair. The transcriptional levels of transporter proteins indicated that the mechanism by which EP-induced CDDP sensitization was intracellular drug accumulation. The protein levels of some antioxidants, such as hemeoxygenase-1 (HO-1), glutathione (GSH) and glutathione peroxidase (Gpx), were decreased in A549 cells exposed to EP via the down-regulation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Furthermore, normal human fibroblasts were resistant to EP treatment, with no elevated DNA damage or apoptosis. Collectively, these data show that administration of EP is a potential adjuvant tool for CDDP-based chemosensitivity of lung cancer cells that may reduce drug resistance.

  14. Appropriateness of Bolus Antihypertensive Therapy for Elevated Blood Pressure in the Emergency Department.

    Science.gov (United States)

    Miller, Joseph B; Arter, Andrew; Wilson, Suprat S; Janke, Alexander T; Brody, Aaron; Reed, Brian P; Levy, Phillip D

    2017-08-01

    While moderate to severely elevated blood pressure (BP) is present in nearly half of all emergency department (ED) patients, the incidence of true hypertensive emergencies in ED patients is low. Administration of bolus intravenous (IV) antihypertensive treatment to lower BP in patients without a true hypertensive emergency is a wasteful practice that is discouraged by hypertension experts; however, anecdotal evidence suggests this occurs with relatively high frequency. Accordingly, we sought to assess the frequency of inappropriate IV antihypertensive treatment in ED patients with elevated BP absent a hypertensive emergency. We performed a retrospective cohort study from a single, urban, teaching hospital. Using pharmacy records, we identified patients age 18-89 who received IV antihypertensive treatment in the ED. We defined treatment as inappropriate if documented suspicion for an indicated cardiovascular condition or acute end-organ injury was lacking. Data abstraction included adverse events and 30-day readmission rates, and analysis was primarily descriptive. We included a total of 357 patients over an 18-month period. The mean age was 55; 51% were male and 93% black, and 127 (36.4%) were considered inappropriately treated. Overall, labetalol (61%) was the most commonly used medication, followed by enalaprilat (18%), hydralazine (18%), and metoprolol (3%). There were no significant differences between appropriate and inappropriate BP treatment groups in terms of clinical characteristics or adverse events. Hypotension or bradycardia occurred in three (2%) patients in the inappropriate treatment cohort and in two (1%) patients in the appropriately treated cohort. Survival to discharge and 30-day ED revisit rates were equivalent. More than one in three patients who were given IV bolus antihypertensive treatment in the ED received such therapy inappropriately by our definition, suggesting that significant resources could perhaps be saved through education of

  15. Appropriateness of Bolus Antihypertensive Therapy for Elevated Blood Pressure in the Emergency Department

    Directory of Open Access Journals (Sweden)

    Joseph B. Miller

    2017-07-01

    Full Text Available Introduction: While moderate to severely elevated blood pressure (BP is present in nearly half of all emergency department (ED patients, the incidence of true hypertensive emergencies in ED patients is low. Administration of bolus intravenous (IV antihypertensive treatment to lower BP in patients without a true hypertensive emergency is a wasteful practice that is discouraged by hypertension experts; however, anecdotal evidence suggests this occurs with relatively high frequency. Accordingly, we sought to assess the frequency of inappropriate IV antihypertensive treatment in ED patients with elevated BP absent a hypertensive emergency. Methods: We performed a retrospective cohort study from a single, urban, teaching hospital. Using pharmacy records, we identified patients age 18–89 who received IV antihypertensive treatment in the ED. We defined treatment as inappropriate if documented suspicion for an indicated cardiovascular condition or acute end-organ injury was lacking. Data abstraction included adverse events and 30-day readmission rates, and analysis was primarily descriptive. Results: We included a total of 357 patients over an 18-month period. The mean age was 55; 51% were male and 93% black, and 127 (36.4% were considered inappropriately treated. Overall, labetalol (61% was the most commonly used medication, followed by enalaprilat (18%, hydralazine (18%, and metoprolol (3%. There were no significant differences between appropriate and inappropriate BP treatment groups in terms of clinical characteristics or adverse events. Hypotension or bradycardia occurred in three (2% patients in the inappropriate treatment cohort and in two (1% patients in the appropriately treated cohort. Survival to discharge and 30-day ED revisit rates were equivalent. Conclusion: More than one in three patients who were given IV bolus antihypertensive treatment in the ED received such therapy inappropriately by our definition, suggesting that significant

  16. Elevated pressure, a novel cancer therapeutic tool for sensitizing cisplatin-mediated apoptosis in A549

    International Nuclear Information System (INIS)

    Oh, Sangnam; Kim, Yanghee; Kim, Joonhee; Kwon, Daeho; Lee, Eunil

    2010-01-01

    Research highlights: → Sensitized apoptosis in cancer cells stimulated by EP precondition with p53 dependence. → EP attenuates several CDDP-resistance mechanisms. → No harmful effect of EP on normal fibroblasts. -- Abstract: Intensive cancer therapy strategies have thus far focused on sensitizing cancer cells to anticancer drug-mediated apoptosis to overcome drug resistance, and this strategy has led to more effective cancer therapeutics. Cisplatin (cis-diamminedichloroplatinum(II), CDDP) is an effective anticancer drug used to treat many types of cancer, including non-small cell lung carcinoma (NSCLC), and can be used in combination with various chemicals to enhance cancer cell apoptosis. Here, we introduce the use of elevated pressure (EP) in combination with CDDP for cancer treatment and explore the effects of EP on CDDP-mediated apoptosis in NSCLC cells. Our findings demonstrate that preconditioning NSCLC cells with EP sensitizes cells for CDDP-induced apoptosis. Enhanced apoptosis was dependent on p53 and HO-1 expression, and was associated with increased DNA damage and down-regulation of genes involved in nucleotide excision repair. The transcriptional levels of transporter proteins indicated that the mechanism by which EP-induced CDDP sensitization was intracellular drug accumulation. The protein levels of some antioxidants, such as hemeoxygenase-1 (HO-1), glutathione (GSH) and glutathione peroxidase (Gpx), were decreased in A549 cells exposed to EP via the down-regulation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Furthermore, normal human fibroblasts were resistant to EP treatment, with no elevated DNA damage or apoptosis. Collectively, these data show that administration of EP is a potential adjuvant tool for CDDP-based chemosensitivity of lung cancer cells that may reduce drug resistance.

  17. Elevated pressure improves the extraction and identification of proteins recovered from formalin-fixed, paraffin-embedded tissue surrogates.

    Directory of Open Access Journals (Sweden)

    Carol B Fowler

    2010-12-01

    Full Text Available Proteomic studies of formalin-fixed paraffin-embedded (FFPE tissues are frustrated by the inability to extract proteins from archival tissue in a form suitable for analysis by 2-D gel electrophoresis or mass spectrometry. This inability arises from the difficulty of reversing formaldehyde-induced protein adducts and cross-links within FFPE tissues. We previously reported the use of elevated hydrostatic pressure as a method for efficient protein recovery from a hen egg-white lysozyme tissue surrogate, a model system developed to study formalin fixation and histochemical processing.In this study, we demonstrate the utility of elevated hydrostatic pressure as a method for efficient protein recovery from FFPE mouse liver tissue and a complex multi-protein FFPE tissue surrogate comprised of hen egg-white lysozyme, bovine carbonic anhydrase, bovine ribonuclease A, bovine serum albumin, and equine myoglobin (55∶15∶15∶10∶5 wt%. Mass spectrometry of the FFPE tissue surrogates retrieved under elevated pressure showed that both the low and high-abundance proteins were identified with sequence coverage comparable to that of the surrogate mixture prior to formaldehyde treatment. In contrast, non-pressure-extracted tissue surrogate samples yielded few positive and many false peptide identifications. Studies with soluble formalin-treated bovine ribonuclease A demonstrated that pressure modestly inhibited the rate of reversal (hydrolysis of formaldehyde-induced protein cross-links. Dynamic light scattering studies suggest that elevated hydrostatic pressure and heat facilitate the recovery of proteins free of formaldehyde adducts and cross-links by promoting protein unfolding and hydration with a concomitant reduction in the average size of the protein aggregates.These studies demonstrate that elevated hydrostatic pressure treatment is a promising approach for improving the recovery of proteins from FFPE tissues in a form suitable for proteomic analysis.

  18. Elevated Pressure Improves the Extraction and Identification of Proteins Recovered from Formalin-Fixed, Paraffin-Embedded Tissue Surrogates

    Science.gov (United States)

    Fowler, Carol B.; Chesnick, Ingrid E.; Moore, Cedric D.; O'Leary, Timothy J.; Mason, Jeffrey T.

    2010-01-01

    Background Proteomic studies of formalin-fixed paraffin-embedded (FFPE) tissues are frustrated by the inability to extract proteins from archival tissue in a form suitable for analysis by 2-D gel electrophoresis or mass spectrometry. This inability arises from the difficulty of reversing formaldehyde-induced protein adducts and cross-links within FFPE tissues. We previously reported the use of elevated hydrostatic pressure as a method for efficient protein recovery from a hen egg-white lysozyme tissue surrogate, a model system developed to study formalin fixation and histochemical processing. Principal Findings In this study, we demonstrate the utility of elevated hydrostatic pressure as a method for efficient protein recovery from FFPE mouse liver tissue and a complex multi-protein FFPE tissue surrogate comprised of hen egg-white lysozyme, bovine carbonic anhydrase, bovine ribonuclease A, bovine serum albumin, and equine myoglobin (55∶15∶15∶10∶5 wt%). Mass spectrometry of the FFPE tissue surrogates retrieved under elevated pressure showed that both the low and high-abundance proteins were identified with sequence coverage comparable to that of the surrogate mixture prior to formaldehyde treatment. In contrast, non-pressure-extracted tissue surrogate samples yielded few positive and many false peptide identifications. Studies with soluble formalin-treated bovine ribonuclease A demonstrated that pressure modestly inhibited the rate of reversal (hydrolysis) of formaldehyde-induced protein cross-links. Dynamic light scattering studies suggest that elevated hydrostatic pressure and heat facilitate the recovery of proteins free of formaldehyde adducts and cross-links by promoting protein unfolding and hydration with a concomitant reduction in the average size of the protein aggregates. Conclusions These studies demonstrate that elevated hydrostatic pressure treatment is a promising approach for improving the recovery of proteins from FFPE tissues in a form

  19. Demonstration of uneven distribution of intracranial pulsatility in hydrocephalus patients.

    Science.gov (United States)

    Eide, Per K

    2008-11-01

    Data from intracranial pressure (ICP) recordings in patients with hydrocephalus were reviewed to determine whether intracranial pulsatility within the cerebrospinal fluid (CSF) of cerebral ventricles (ICP(LV)) may differ from that within the brain parenchyma (ICP(PAR)), and whether pulsatility may differ between noncommunicating ventricles. The authors retrieved data from recordings previously obtained in 7 patients with hydrocephalus (noncommunicating in 4 and communicating in 3) and shunt failure who received both an external ventricular drainage (EVD) and an ICP sensor as part of surveillance during intensive care. Simultaneous ICP(LV) and ICP(PAR) signals were available in 6 cases, and simultaneous signals from the lateral and fourth ventricles (ICP(LV) and ICP4V, respectively) were recorded in 1 case. The recordings with both signals were parsed into 6-second time windows. Pulsatility was characterized by the wave amplitude and rise time coefficient, and differences in pulsatility between the ICP(LV) and ICP(PAR) signals (6 cases) or ICP(LV) and ICP4V signals (1 case) were determined. There was uneven distribution of intracranial pulsatility in all 7 patients, shown as significantly elevated pulsatility (that is, higher wave amplitudes and rise time coefficients) within the ventricles (ICP(LV)) than within brain parenchyma (ICP(PAR)) in 6 patients, and significantly higher pulsatility in the fourth (ICP4V) than in the lateral (ICP(LV)) ventricles in 1 patient. Differences > or = 1 mm Hg in ICP wave amplitude were found in 0.5-100% (median 9.4%) of observations in the 7 patients (total number of 6-second time windows, 68,242). The present observations demonstrate uneven distribution of intracranial pulsatility in patients with hydrocephalus, higher pulse pressure amplitudes within the ventricular CSF (ICP(LV)) than within the brain parenchyma (ICP(PAR)). This may be one mechanism behind ventricular enlargement in hydrocephalus.

  20. Elevated blood pressure and its predictors among secondary school students in Sarawak: a cross-sectional study.

    Science.gov (United States)

    Grace Kho, Woei Feng; Cheah, Whye Lian; Hazmi, Helmy

    2018-03-01

    Hypertension is a health issue affecting adolescents. Accumulating evidence affirms that elevated blood pressure begins in childhood and tracks into adulthood. This cross-sectional study was conducted to determine the prevalence of elevated blood pressure and its predictors among secondary school students in Sarawak, Malaysia. A total of 2,461 secondary school students aged 12-17 years from 19 schools in Sarawak participated in the study. Questionnaire was used to obtain socio-demographic data, parental history of hypertension, and self-reported physical activity. Anthropometric and blood pressure measurements were taken. Data was entered and analysed using SPSS version 23.0. The prevalence of adolescents with elevated blood pressure, overweight, central obesity, and overfat were 30.1%, 24.3%, 13.5%, and 6.7%, respectively. Multivariate logistic regression demonstrated the predictors significantly associated with elevated blood pressure among respondents: overweight (adjusted odds ratio=3.144), being male (adjusted odds ratio=3.073), being Chinese (adjusted odds ratio=2.321) or Iban (adjusted odds ratio=1.578), central obesity (adjusted odds ratio=2.145), being overfat (adjusted odds ratio=1.885), and being an older adolescent (adjusted odds ratio=1.109). Parental history of hypertension, locality, and physical activity showed no significant associations. The obesity epidemic must be tackled at community and school levels by health education and regulation of school canteen foods. Copyright© by the National Institute of Public Health, Prague 2018.

  1. Consideration of the Intracranial Pressure Threshold Value for the Initiation of Traumatic Brain Injury Treatment: A Xenon CT and Perfusion CT Study.

    Science.gov (United States)

    Honda, Mitsuru; Ichibayashi, Ryo; Suzuki, Ginga; Yokomuro, Hiroki; Seiki, Yoshikatsu; Sase, Shigeru; Kishi, Taichi

    2017-12-01

    Monitoring of intracranial pressure (ICP) is considered to be fundamental for the care of patients with severe traumatic brain injury (TBI) and is routinely used to direct medical and surgical therapy. Accordingly, some guidelines for the management of severe TBI recommend that treatment be initiated for ICP values >20 mmHg. However, it remained to be accounted whether there is a scientific basis to this instruction. The purpose of the present study was to clarify whether the basis of ICP values >20 mmHg is appropriate. We retrospectively reviewed 25 patients with severe TBI who underwent neuroimaging during ICP monitoring within the first 7 days. We measured cerebral blood flow (CBF), mean transit time (MTT), cerebral blood volume (CBV), and ICP 71 times within the first 7 days. Although the CBF, MTT, and CBV values were not correlated with the ICP value at ICP values ≤20 mmHg, the CBF value was significantly negatively correlated with the ICP value (r = -0.381, P values >20 mmHg. The MTT value was also significantly positively correlated with the ICP value (r = 0.638, P values >20 mmHg. The cerebral circulation disturbance increased with the ICP value. We demonstrated the cerebral circulation disturbance at ICP values >20 mmHg. This study suggests that an ICP >20 mmHg is the threshold to initiate treatments. An active treatment intervention would be required for severe TBI when the ICP was >20 mmHg.

  2. The effects and regulatory mechanism of RIP3 on RGC-5 necroptosis following elevated hydrostatic pressure.

    Science.gov (United States)

    Shang, Lei; Ding, Wei; Li, Na; Liao, Lvshuang; Chen, Dan; Huang, Jufang; Xiong, Kun

    2017-02-06

    Necroptosis is a type of regulated cell death that has been implicated in various diseases. Receptor-interacting protein 3 (RIP3), a member of the RIP family, is an important mediator of the necroptotic pathway. Cleavage of RIP3 at Asp328 by caspase-8 abolishes the kinase activity of RIP3, which is critical for necroptosis. Moreover, RIP3 is significantly upregulated during the early stages of acute high intra-ocular pressure and oxygen glucose deprivation. In this study, the effects of RIP3 during elevated hydrostatic pressure (EHP) were investigated and the possible mechanism through which caspase-8 regulated RIP3 cleavage was explored. Flow cytometry analysis revealed that the number of EHP-induced necrotic retinal ganglion cell 5 (RGC-5) cells was reduced after RIP3-knockdown. Furthermore, malondialdehyde (MDA) levels and glycogen phosphorylase (PYGL) activity in normal RGC-5 cells were much higher than those in RIP3-knockdown cells after EHP. EHP-induced RGC-5 necrosis was significantly reduced after treatment with butylated hydroxyanisole (BHA), a reactive oxygen species (ROS) scavenger. MDA levels and PYGL activity were lower in normal RGC-5 cells than those in cells with caspase-8 inhibition after EHP. Western blot analysis demonstrated that the RIP3 cleavage product was upregulated in cells with caspase-8 inhibition. Additionally, flow cytometry analysis revealed that the number of EHP-induced necrotic RGC-5 cells was increased after caspase-8 inhibition. Our results suggested that RGC-5 necroptosis following EHP was mediated by RIP3 through induction of PYGL activity and subsequent ROS accumulation. Thus, caspase-8 may participate in the regulation of RGC-5 necroptosis via RIP3 cleavage. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Grade III or Grade IV Hypertensive Retinopathy with Severely Elevated Blood Pressure

    Directory of Open Access Journals (Sweden)

    Amanda D Henderson

    2012-12-01

    Full Text Available Introduction: Hypertensive retinopathy describes a spectrum of retinal changes in patients with elevated blood pressure (BP. It is unknown why some patients are more likely to develop acute ocular end-organ damage than others with similar BP. We examined risk factors for grade III/IV hypertensive retinopathy among patients with hypertensive urgency in the emergency department (ED and compared healthcare utilization and mortality between patients with and without grade III/IV hypertensive retinopathy.Methods: A preplanned subanalysis of patients who presented to a university hospital ED with diastolic BP > 120 mmHg and who enrolled in the Fundus Photography versus Ophthalmoscopy Trial Outcomes in the ED study was performed. Bilateral nonmydriatic ocular fundus photographs, vital signs, and demographics were obtained at presentation. Past medical history, laboratory values, healthcare utilization, and mortality were ascertained from medical record review at least 8 months after initial ED visit.Results: Twenty-one patients with diastolic BP > 120 mmHg, 7 of whom (33% had grade III/IV hypertensive retinopathy, were included. Patients with retinopathy were significantly younger than those without (median 33 vs 50 years, P = 0.02. Mean arterial pressure (165 vs 163 mmHg was essentially equal in the 2 groups. Patients with retinopathy had substantially increased but nonsignificant rates of ED revisit (57% vs 29%, P = 0.35 and hospital admission after ED discharge (43% vs 14%, P = 0.28. One of the patients with retinopathy died, but none without.Conclusion: Younger patients may be at higher risk for grade III/IV hypertensive retinopathy among patients with hypertensive urgency. Chronic compensatory mechanisms may have not yet developed in these younger patients. Alternatively, older patients with retinopathy may be underrepresented secondary to increased mortality among these patients at a younger age (survivorship bias. Further research is needed to

  4. A Secure Automated Elevator Management System and Pressure Sensor based Floor Estimation for Indoor Mobile Robot Transportation

    Directory of Open Access Journals (Sweden)

    Ali Abduljalil Abdulla

    2017-08-01

    Full Text Available In this paper, a secure elevator handling system is presented to enable a flexible movement of wheeled mobile robots among laboratories distributed in different floors. The automated handling system consists mainly of an ADAM module which has the ability to call the elevator to the robot’s current floor and to request the destination floor. The LPS25HP pressure sensor attached to an STM32F411 microcontroller is utilized as a height measurement system to estimate the robot’s current floor inside the elevator. The ultrasonic sensor is used to recognize the elevator’s door status. Many challenges have to be solved to realize a stable height measurement system based on pressure sensor readings. The difference of the pressure sensor readings before and after soldering is realized by comparing the reading after soldering with an accurate barometric reading. In addition, the sensor output signal shows oscillation and wide variation of the same floor pressure sensor readings at different times. The oscillation in the output signal has been handled using a first order FIR smoothing filter. The first order filter was selected to balance between the stability and the elapsed time to receive the updated values. An auto-calibration stage is established to maintain the wide variation in the atmospheric pressure readings by calibrating the sensor readings with the robot’s current floor before entering the elevator. An error handling management system is utilized to guarantee a stable automated elevator management system performance. Many experiments to assess and verify the performance of the automated elevator management system and robot’s current floor estimation are reported. The experimental results show that the proposed methods and sub-systems developed for the mobile robot are effective and efficient in providing a transportation service in multiple-floor life sciences laboratories.

  5. Effects of arm elevation on radial artery pressure: a new method to distinguish hypovolemic shock and septic shock from hypotension.

    Science.gov (United States)

    Xie, Zhiyi; Zhang, Zhenyu; Xu, Yuan; Zhou, Hua; Wu, Sheng; Wang, Zhong

    2018-06-01

    In this prospective observational study, we investigated the variability in radial artery invasive blood pressure associated with arm elevation in patients with different hemodynamic types. We carried out a prospective observational study using data from 73 general anesthesia hepatobiliary postoperative adult patients admitted to an ICU over a 1-year period. A standard procedure was used for the arm elevation test. The value of invasive radial arterial pressure was recorded at baseline, and 30 and 60 s after the arm had been raised from 0° to 90°. We compared the blood pressure before versus after arm elevation, and between hemodynamically stable, hypovolemic shock, and septic shock patient groups. In all 73 patients, systolic arterial pressure (SAP) decreased, diastolic arterial pressure (DAP) increased, and pulse pressure (PP) decreased at 30 and 60 s after arm elevation (Ppressure (MAP) was unchanged (P>0.05). On comparing 30 and 60 s, there was no significant difference in SAP, DAP, PP, or MAP (P>0.05). In 40 hemodynamically stable patients, SAP and PP decreased, and DAP and MAP increased significantly at 30 and 60 s after arm elevation compared with baseline (P0.05). In 17 patients with septic shock, SAP, PP, and MAP decreased significantly versus baseline at 30 and 60 s (P0.05). Comparison of the absolute value of pressure change of septic shock patients at 30 s after raising the arm showed that SAP, DAP, and MAP changes were significantly lower compared with those in hypovolemic shock and hemodynamically stable patients (Parm elevation of SAP. The best cut-off point for the SAP change value was -5 mmHg or less, with a sensitivity of 94.12%, a specificity of 80.36%, a positive likelihood ratio of 4.79 (95% CI: 2.8-8.2), and a negative likelihood ratio of 0.073 (95% CI: 0.01-0.5). Our study shows that hypovolemic shock and septic shock patients have significantly different radial artery invasive blood pressure changes in an arm elevation test

  6. Dry reforming of methane with CO{sub 2} at elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Milanov, A.; Schwab, E.; Wasserschaff, G. [BASF SE, Ludwigshafen (Germany); Schunk, S. [hte AG, Heidelberg (Germany)

    2013-11-01

    The indirect conversion of natural gas into higher value chemicals and fuels via syngas is superior with regard to efficiency compared to the currently available direct conversion technologies and remains the industrially preferred route. Typically the syngas production route is generally dictated by the H{sub 2}/CO ratio requirements of the downstream synthesis process. Processes such as direct DME synthesis, high-temperature Fischer-Tropsch and acetic acid synthesis require CO rich syngas that is not readily accessible by established technologies like steam methane reforming (SMR) and autothermal reforming of methane (ATR). The CO{sub 2} reforming of methane, also known as dry reforming (DRM), is an attractive alternative technology for the production of CO-rich syngas. This paper gives an overview of the current joint research activities at BASF and hte AG aiming to develop suitable catalysts for CO{sub 2} reforming of methane at elevated pressures with minimized input of process steam. The performance profiles of two newly developed base metal catalysts are presented and discussed. The catalysts exhibit high degrees of methane and CO{sub 2} conversion in combination with an extraordinary coking resistance under high severity process conditions. (orig.)

  7. Association of "Elevated Blood Pressure" and "Stage 1 Hypertension" With Cardiovascular Mortality Among an Asian Population.

    Science.gov (United States)

    Talaei, Mohammad; Hosseini, Naeimeh; Koh, Angela S; Yuan, Jian-Min; Koh, Woon-Puay

    2018-04-10

    The new American College of Cardiology/American Heart Association high blood pressure (BP) guidelines in the United States have lowered definition of hypertension by defining normal as systolic/diastolic BP hypertension as systolic between 130 and 139 mm Hg or diastolic between 80 and 89 mm Hg. We investigated the association between the new hypertension definition and cardiovascular disease mortality among Chinese in Singapore. We used data from 30 636 participants of a population-based cohort, the SCHS (Singapore Chinese Health Study), who had BPs measured using a standard protocol at ages 46 to 85 years between 1994 and 2005. Information on lifestyle factors was collected at recruitment (1993-1998) and follow-up 1 interviews (1999 and 2004). Mortality was identified via nationwide registry linkage up to December 31, 2016. Neither elevated BP (hazard ratio, 0.89; 95% confidence interval, 0.74-1.07) nor stage 1 hypertension (hazard ratio, 0.94; 95% confidence interval, 0.81-1.11) was associated with increased risk of cardiovascular mortality compared with normal BP in the whole cohort. Stage 1 hypertension was associated with increased cardiovascular risk only in those hypertension may not be associated with increased cardiovascular mortality across all ages among Chinese in Singapore, but that the at-risk subpopulation is limited to those <65 years of age and without a prior cardiovascular disease. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  8. One elevated bladder pressure measurement may not be enough to diagnose abdominal compartment syndrome.

    Science.gov (United States)

    Young, Andrew Joseph; Weber, William; Wolfe, Luke; Ivatury, Rao R; Duane, Therese Marie

    2013-02-01

    Bladder pressure measurements (BPMs) are considered a key component in the diagnosis of abdominal compartment syndrome (ACS). The purpose of this observational review was to determine risk factors of ACS and associated mortality with particular focus on the role of BPM. A retrospective trauma registry and chart review was performed on trauma patients from January 2003 through December 2010. Comparisons were made between patients with and without ACS. There were 3172 patients included in the study of whom 46 had ACS. Patients with ACS were younger, more severely injured, with longer lengths of stay. Logistic regression determined Injury Severity Score (ISS) and urinary catheter days as independent predictors of ACS, whereas independent predictors of mortality included age, ISS, and ACS. Subset analysis demonstrated no association between BPM 20 mmHg or greater and diagnosis of ACS versus no ACS. Logistic regression indicated independent predictors of mortality were number of BPM 20 mmHg or greater and age. Patients with ACS are more severely injured with worse outcomes. An isolated BPM 20 mmHg or greater was not associated with ACS and may be inadequate to independently diagnose ACS. These findings suggest the need for repeat measurements with early intervention if they remain elevated in an effort to decrease mortality associated with ACS.

  9. Blood pressure-to-height ratio as a screening indicator of elevated blood pressure among children and adolescents in Chongqing, China.

    Science.gov (United States)

    Wang, L Y; Liu, Q; Cheng, X T; Jiang, J J; Wang, H

    2017-07-01

    We aimed to evaluate the performance of blood pressure-to-height ratio (BPHR) and establish their optimal thresholds for elevated blood pressure (BP) among children aged 6 to 17 years in Chongqing, China. Data were collected from 11 029 children and adolescents aged 6-17 years in 12 schools in Chongqing according to multistage stratified cluster sampling method. The gold standard for elevated BP was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ⩾95th percentile for gender, age and height. The diagnostic performance of systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) to screen for elevated BP was evaluated through receiver-operating characteristic curves (including the area under the curve (AUC) and its 95% confidence interval, sensitivity and specificity). The prevalence of elevated BP in children and adolescents in Chongqing was 10.36% by SBP and/or DBP ⩾95th percentile for gender, age and height. The optimal thresholds of SBPHR/DBPHR for identifying elevated BP were 0.86/0.58 for boys and 0.85/0.57 for girls among children aged 6 to 8 years, 0.81/0.53 for boys and 0.80/0.52 for girls among children aged 9 to 11 years and 0.71/0.45 for boys and 0.72/0.47 for girls among adolescents aged 12-17 years, respectively. Across gender and the specified age groups, AUC ranged from 0.82 to 0.88, sensitivity were above 0.94 and the specificities were over 0.7. The positive predictive values ranged from 0.30 to 0.38 and the negative predictive values were ⩾0.99. BPHR, with uniform values across broad age groups (6-8, 9-11 and 12-17 years) for boys and for girls is a simple indicator to screen elevated BP in children and adolescents in Chongqing.

  10. ATR-IR spectroscopic cell for in situ studies at solid-liquid interface at elevated temperatures and pressures

    NARCIS (Netherlands)

    Koichumanova, Kamila; Visan, Aura; Geerdink, Bert; Lammertink, Rob G.H.; Mojet, Barbara; Seshan, Kulathuiyer; Lefferts, Leonardus

    2017-01-01

    An in situ ATR-IR spectroscopic cell suitable for studies at solid-liquid interface is described including the design and experimental details in continuous flow mode at elevated temperatures (230 °C) and pressures (30 bar). The design parameters considered include the cell geometry, the procedure

  11. Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

    NARCIS (Netherlands)

    Chintalapudi, S.R. (Sumana R.); Maria, D. (Doaa); Di Wang, X. (Xiang); Bailey, J.N.C. (Jessica N. Cooke); Allingham, R. (Rand); M.H. Brilliant (Murray H.); D.L. Budenz (Donald L.); J. Fingert (John); D. Gaasterland (Douglas); T. Gaasterland (Terry); J.L. Haines (Jonathan); Hark, L. (Lisa); M.A. Hauser (Michael); R.P. Igo Jr. (Robert); Hee Kang, J. (Jae); P. Kraft (Peter); R.K. Lee (Richard K.); P.A. Lichter (Paul A.); Liu, Y. (Yutao); Moroi, S. (Syoko); L.R. Pasquale (Louis); M.A. Pericak-Vance (Margaret); A. Realini (Anthony); Rhee, D. (Doug); Richards, J.R. (Julia R.); Ritch, R. (Robert); J.S. Schuman (Joel S.); W.K. Scott (William); K. Singh (Kuldev); A.J. Sit (Arthur J.); D. Vollrath (Douglas); G. Wollstein (Gadi); D.J. Zack (Donald); T. Aung (Tin); Bonnemaijer, P. (Peter); Cheng, C.-Y. (Cheng-Yu); J.E. Craig (Jamie); C.M. van Duijn (Cornelia); P. Gharahkhani (Puya); Iglesias Gonzalez, A. (Adriana); Hammond, C.J. (Christopher J.); Hewitt, A. (Alex); Hoehn, R. (Rene); Jonansson, F. (Fridbert); A.P. Khawaja (Anthony); Chuen Khor, C. (Chiea); C.C.W. Klaver (Caroline); A.J. Lotery (Andrew); D.A. Mackey (David); MacGregor, S. (Stuart); Pang, C. (Calvin); F. Pasutto (Francesca); J-A. Zwart (John-Anker); G. Thorleifsson (Gudmar); Thorsteinsdottir, U. (Unnar); V. Vitart (Veronique); E.N. Vithana (Eranga); T.L. Young (Terri L.); T. Zeller (Tanja); P.G. Hysi (Pirro); J.L. Wiggs (Janey L.); R.W. Williams (Robert W.); Jablonski, M.M. (Monica M.)

    2017-01-01

    textabstractGlaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand

  12. An Update on Idiopathic Intracranial Hypertension

    OpenAIRE

    Thurtell, Matthew J.; Bruce, Beau B.; Newman, Nancy J.; Biousse, Valérie

    2010-01-01

    Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology often encountered in neurologic practice. It produces non-localizing symptoms and signs of raised intracranial pressure and, when left untreated, can result in severe irreversible visual loss. It most commonly occurs in obese women of childbearing age, but it can also occur in children, men, non-obese adults, and older adults. While it is frequently associated with obesity, it can be associated with other conditions...

  13. Graves' disease and idiopathic intracranial hypertension

    OpenAIRE

    Manish Gutch; Annesh Bhattacharjee; Sukriti Kumar; Durgesh Pushkar

    2017-01-01

    Idiopathic intracranial hypertension (IIH) is a central nervous system disorder characterized by raised intracranial pressure with normal cerebrospinal fluid composition and absence of any structural anomaly on neuroimaging. Among all endocrine disorders associated with the development of IIH, the association of hyperthyroidism and IIH is very rare with few cases reported till date. Thyroid disturbances have a unique association with IIH. Hypo- and hyper-thyroidism have been reported in assoc...

  14. Apparatus and method for direct measurement of coal ash sintering and fusion properties at elevated temperatures and pressures

    Science.gov (United States)

    Khan, M. Rashid

    1990-01-01

    A high-pressure microdilatometer is provided for measuring the sintering and fusion properties of various coal ashes under the influence of elevated pressures and temperatures in various atmospheres. Electrical resistivity measurements across a sample of coal ash provide a measurement of the onset of the sintering and fusion of the ash particulates while the contraction of the sample during sintering is measured with a linear variable displacement transducer for detecting the initiation of sintering. These measurements of sintering in coal ash at different pressures provide a mechanism by which deleterious problems due to the sintering and fusion of ash in various combustion systems can be minimized or obviated.

  15. Effect of Soret diffusion on lean hydrogen/air flames at normal and elevated pressure and temperature

    KAUST Repository

    Zhou, Zhen; Hernandez Perez, Francisco; Shoshin, Yuriy; van Oijen, Jeroen A.; de Goey, Laurentius P.H.

    2017-01-01

    The influence of Soret diffusion on lean premixed flames propagating in hydrogen/air mixtures is numerically investigated with a detailed chemical and transport models at normal and elevated pressure and temperature. The Soret diffusion influence on the one-dimensional (1D) flame mass burning rate and two-dimensional (2D) flame propagating characteristics is analysed, revealing a strong dependency on flame stretch rate, pressure and temperature. For 1D flames, at normal pressure and temperature, with an increase of Karlovitz number from 0 to 0.4, the mass burning rate is first reduced and then enhanced by Soret diffusion of H2 while it is reduced by Soret diffusion of H. The influence of Soret diffusion of H2 is enhanced by pressure and reduced by temperature. On the contrary, the influence of Soret diffusion of H is reduced by pressure and enhanced by temperature. For 2D flames, at normal pressure and temperature, during the early phase of flame evolution, flames with Soret diffusion display more curved flame cells. Pressure enhances this effect, while temperature reduces it. The influence of Soret diffusion of H2 on the global consumption speed is enhanced at elevated pressure. The influence of Soret diffusion of H on the global consumption speed is enhanced at elevated temperature. The flame evolution is more affected by Soret diffusion in the early phase of propagation than in the long run due to the local enrichment of H2 caused by flame curvature effects. The present study provides new insights into the Soret diffusion effect on the characteristics of lean hydrogen/air flames at conditions that are relevant to practical applications, e.g. gas engines and turbines.

  16. Effect of Soret diffusion on lean hydrogen/air flames at normal and elevated pressure and temperature

    KAUST Repository

    Zhou, Zhen

    2017-04-12

    The influence of Soret diffusion on lean premixed flames propagating in hydrogen/air mixtures is numerically investigated with a detailed chemical and transport models at normal and elevated pressure and temperature. The Soret diffusion influence on the one-dimensional (1D) flame mass burning rate and two-dimensional (2D) flame propagating characteristics is analysed, revealing a strong dependency on flame stretch rate, pressure and temperature. For 1D flames, at normal pressure and temperature, with an increase of Karlovitz number from 0 to 0.4, the mass burning rate is first reduced and then enhanced by Soret diffusion of H2 while it is reduced by Soret diffusion of H. The influence of Soret diffusion of H2 is enhanced by pressure and reduced by temperature. On the contrary, the influence of Soret diffusion of H is reduced by pressure and enhanced by temperature. For 2D flames, at normal pressure and temperature, during the early phase of flame evolution, flames with Soret diffusion display more curved flame cells. Pressure enhances this effect, while temperature reduces it. The influence of Soret diffusion of H2 on the global consumption speed is enhanced at elevated pressure. The influence of Soret diffusion of H on the global consumption speed is enhanced at elevated temperature. The flame evolution is more affected by Soret diffusion in the early phase of propagation than in the long run due to the local enrichment of H2 caused by flame curvature effects. The present study provides new insights into the Soret diffusion effect on the characteristics of lean hydrogen/air flames at conditions that are relevant to practical applications, e.g. gas engines and turbines.

  17. Spaceflight-Induced Intracranial Hypertension.

    Science.gov (United States)

    Michael, Alex P; Marshall-Bowman, Karina

    2015-06-01

    Although once a widely speculated about and largely theoretical topic, spaceflight-induced intracranial hypertension has gained acceptance as a distinct clinical phenomenon, yet the underlying physiological mechanisms are still poorly understood. In the past, many terms were used to describe the symptoms of malaise, nausea, vomiting, and vertigo, though longer duration spaceflights have increased the prevalence of overlapping symptoms of headache and visual disturbance. Spaceflight-induced visual pathology is thought to be a manifestation of increased intracranial pressure (ICP) because of its similar presentation to cases of known intracranial hypertension on Earth as well as the documentation of increased ICP by lumbar puncture in symptomatic astronauts upon return to gravity. The most likely mechanisms of spaceflight-induced increased ICP include a cephalad shift of body fluids, venous outflow obstruction, blood-brain barrier breakdown, and disruption to CSF flow. The relative contribution of increased ICP to the symptoms experienced during spaceflight is currently unknown, though other factors recently posited to contribute include local effects on ocular structures, individual differences in metabolism, and the vasodilator effects of carbon dioxide. This review article attempts to consolidate the literature regarding spaceflight-induced intracranial hypertension and distinguish it from other pathologies with similar symptomatology. It discusses the proposed physiological causes and the pathological manifestations of increased ICP in the spaceflight environment and provides considerations for future long-term space travel. In the future, it will be critical to develop countermeasures so that astronauts can participate at their peak potential and return safely to Earth.

  18. Hipertensão venosa episcleral idiopática unilateral em mulher jovem Unilateral idiopathic elevated episcleral venous pressure in a young woman

    Directory of Open Access Journals (Sweden)

    Marcelo Mendes Lavezzo

    2013-02-01

    Full Text Available O objetivo é relatar o caso de uma paciente de 33 anos, que veio ao Pronto Socorro de Oftalmologia apresentando queixa de redução da acuidade visual à esquerda, de caráter insidioso e progressivo, há dois anos. Ao exame oftalmológico, apresentava ingurgitamento dos vasos da conjuntiva bulbar, pressão intraocular muito elevada e nervo óptico com escavação total à esquerda. Foi submetida à campimetria computadorizada 24:2 WW e SITA-SWAP do olho direito, ambas com resultados dentro da normalidade. As tomografias de crânio e órbitas, bem como ultrassonografia com doppler do globo ocular, artérias oftálmicas e veias supraorbitárias não apresentavam anormalidades. Diante disso, aventou-se a hipótese diagnóstica de hipertensão venosa episcleral idiopática, um diagnóstico de exclusão, visto que patologias intracranianas e intraorbitárias haviam sido excluídas. Paciente foi tratada clinicamente com colírios hipotensores, com redução importante da pressão intraocular à esquerda, porém não o suficiente, evoluindo para trabeculectomia.The objective is to report a 33 year old female who came to the emergency room of Ophthalmology complaining of reduced visual acuity on the left eye, in a progressive and insidious way, about two years ago. In the ophthalmological examination, she presented dilated tortuous vessels in her left bulbar conjunctiva, very high intraocular pressure and increased cupping of the optic disc. SITA-SWAP and 24:2 computed perimetry were performed on the right eye, both within normal limits. CT scans of the skull and orbits, and ultrasonography of the eyeball and doppler of the ophthalmic artery and the supra-orbital veins had no abnormalities. Thus, it was suggested the possibility of idiopathic elevated episcleral venous pressure, an exclusion diagnosis, since intra-cranial and intraorbital pathologies were excluded. The patient was treated medically with hypotensive eyedrops, with significant reduction

  19. Cerebral blood flow autoregulation during intracranial hypertension in hypoxic lambs

    International Nuclear Information System (INIS)

    Borel, C.O.; Backofen, J.E.; Koehler, R.C.; Jones, M.D. Jr.; Traystman, R.J.

    1987-01-01

    The authors tested the hypothesis that hypoxic hypoxia interferes with cerebral blood flow (CBF) autoregulation when intracranial pressure (ICP) is elevated in pentobarbital-anesthetized lambs (3 to 9 days old). Cerebral perfusion pressure (CPP) was lowered stepwise from 73 to 23 mmHg in eight normoxic lambs and from 65 to 31 mmHg in eight other hypoxic lambs by ventricular infusion of artificial cerebrospinal fluid. In normoxic lambs, CBF measured by microspheres labeled with six different radioisotopes was not significantly changed over this range of CPP. In animals made hypoxic, base-line CBF was twice that of normoxic lambs. CBF was unchanged as CPP was reduced to 31 mmHg. Lower levels of CPP were not attained because a pressor response occurred with further elevations of ICP. No regional decrements in blood flow to cortical arterial watershed areas or to more caudal regions, such as cerebellum, brain stem, or thalamus, were detected with elevated ICP. Cerebral O 2 uptake was similar in both groups and did not decrease when CPP was reduced. These results demonstrate that normoxic lambs have a considerable capacity for effective autoregulation of CBF when ICP is elevated. Moreover, cerebral vasodilation in response to a level of hypoxia approximating that normally seen prenatally does not abolish CBF autoregulation when ICP is elevated during the first postnatal week

  20. The "Skull Flap" a new conceived device for decompressive craniectomy experimental study on dogs to evaluate the safety and efficacy in reducing intracranial pressure and subsequent impact on brain perfusion.

    Science.gov (United States)

    Salvatore, Chibbaro; Fabrice, Vallee; Marco, Marsella; Leonardo, Tigan; Thomas, Lilin; Benoit, Lecuelle; Bernard, George; Pierre, Kehrli; Eric, Vicaut; Paolo, Diemidio

    2013-10-01

    Decompressive craniectomy (DC) is a procedure performed increasingly often in current neurosurgical practice. Significant perioperative morbidity may be associated to this procedure because of the large skull defect; also, later closure of the skull defect (cranioplasty) may be associated to post-operative morbidity as much as any other reconstructive operation. The authors present a newly conceived/developed device: The "Skull Flap" (SF). This system, placed at the time of the craniectomy, offers the possibility to provide cranial reconstruction sparing patients a second operation. In other words, DC and cranioplasty essentially take place at the same time and in addition, patients retain their own bone flap. The current study conducted on animal models, represents the logical continuation of a prior recent study, realized on cadaver specimens, to assess the efficacy and safety of this recently developed device. This is an experimental pilot study on dogs to assess both safety and efficacy of the SF device. Two groups of experimental raised intracranial pressure animal models underwent DC; in the first group of dogs, the bone flap was left in raised position above the skull defect using the SF device; on the second group the flap was discarded. All dogs underwent transcranial Doppler (TCD) to assess brain perfusion. Head computed tomography (CT) scan to determine flap position was also obtained in the group in which the SF device was placed. SF has proved to be a strong fixation device that allows satisfactory brain decompression by keeping the bone flap elevated from the swollen brain; later on, the SF allows cranial reconstruction in a simple way without requiring a second staged operation. In addition, it is relevant to note that brain perfusion was measured and found to be better in the group receiving the SF (while the flap being in a raised as well as in its natural position) comparing to the other group. The SF device has proved to be very easy to place

  1. The "Skull Flap" a new conceived device for decompressive craniectomy experimental study on dogs to evaluate the safety and efficacy in reducing intracranial pressure and subsequent impact on brain perfusion

    Directory of Open Access Journals (Sweden)

    Chibbaro Salvatore

    2013-01-01

    Full Text Available Background: Decompressive craniectomy (DC is a procedure performed increasingly often in current neurosurgical practice. Significant perioperative morbidity may be associated to this procedure because of the large skull defect; also, later closure of the skull defect (cranioplasty may be associated to post-operative morbidity as much as any other reconstructive operation. The authors present a newly conceived/developed device: The "Skull Flap" (SF. This system, placed at the time of the craniectomy, offers the possibility to provide cranial reconstruction sparing patients a second operation. In other words, DC and cranioplasty essentially take place at the same time and in addition, patients retain their own bone flap. The current study conducted on animal models, represents the logical continuation of a prior recent study, realized on cadaver specimens, to assess the efficacy and safety of this recently developed device. Materials and Methods: This is an experimental pilot study on dogs to assess both safety and efficacy of the SF device. Two groups of experimental raised intracranial pressure animal models underwent DC; in the first group of dogs, the bone flap was left in raised position above the skull defect using the SF device; on the second group the flap was discarded. All dogs underwent transcranial Doppler (TCD to assess brain perfusion. Head computed tomography (CT scan to determine flap position was also obtained in the group in which the SF device was placed. Results: SF has proved to be a strong fixation device that allows satisfactory brain decompression by keeping the bone flap elevated from the swollen brain; later on, the SF allows cranial reconstruction in a simple way without requiring a second staged operation. In addition, it is relevant to note that brain perfusion was measured and found to be better in the group receiving the SF (while the flap being in a raised as well as in its natural position comparing to the other

  2. Influence of Child and Adult Elevated Blood Pressure on Adult Arterial Stiffness: The Cardiovascular Risk in Young Finns Study.

    Science.gov (United States)

    Aatola, Heikki; Koivistoinen, Teemu; Tuominen, Heikki; Juonala, Markus; Lehtimäki, Terho; Viikari, Jorma S A; Raitakari, Olli T; Kähönen, Mika; Hutri-Kähönen, Nina

    2017-09-01

    Elevated blood pressure (BP) in childhood has been associated with increased adult arterial stiffness, the independent predictor of cardiovascular and all-cause mortality. The favorable BP change from childhood to adulthood and the risk of high adult arterial stiffness has not been reported. We examined the effect of child and adult BP on pulse wave velocity (PWV) assessed in adulthood among 1540 white adults followed-up for 27 years since baseline (1980, aged 6-18 years). Childhood elevated BP was defined according to the tables from the National High Blood Pressure Education Program. In adulthood, BP was classified as elevated if systolic BP ≥120 mm Hg, diastolic BP ≥80 mm Hg, or self-reported use of antihypertensive medications. PWV was measured in 2007 by whole-body impedance cardiography, and high PWV was defined as values at or above the age-, sex-, and heart rate-specific 80th percentile. Individuals with persistently elevated BP and individuals with normal child but elevated adult BP had increased risk of high adult PWV (relative risk [95% confidence interval], 3.18 [2.22-4.55] and 2.64 [1.79-3.88], respectively) in comparison with individuals with normal (both child and adult) BP. In contrast, individuals with elevated BP in childhood but not in adulthood did not have significantly increased risk of high PWV (relative risk [95% confidence interval], 1.26[0.80-1.99]). The results were consistent when different definitions for child and adult elevated BP were applied. These findings highlight the importance of BP control in the primary prevention of cardiovascular diseases. © 2017 American Heart Association, Inc.

  3. Excessive blood pressure elevation upon awakening involves an exaggerated cardiac response to slight physical activity: a possible mechanism underlying the risk of 'morning surge'.

    Science.gov (United States)

    Wakamatsu, Yoshimasa; Takeda, Yutaka; Tanaka, Satoru; Yamamoto, Koji; Yamashita, Sumiyo; Sugiura, Tomonori; Dohi, Yasuaki; Kimura, Genjiro

    2012-10-01

    An exaggerated elevation in blood pressure around waking potentially increases the risk of cardiovascular events, even in individuals with normal blood pressure at other-fold of day. The impact of such a transient blood pressure elevation is disproportionate to its short duration, and the reason has not been elucidated. We hypothesize that individuals with such a blood pressure abnormality receive a cardiovascular overload, even from slight physical activities that are frequently undertaken in daily life. A total of 16 patients with essential hypertension (52 ± 15 years) staying at hospital for lifestyle education participated in this study. Morning blood pressure elevation was assessed with 24 h ambulatory blood pressure monitoring. Cardiovascular responses to unloaded pedaling, including blood pressure changes, were assessed in a limited maximum exercise test using an electronically braked bicycle ergometer. Changes in the systolic blood pressure caused by unloaded pedaling correlated positively with the elevation in systolic blood pressure around waking (r = 0.52, P = 0.05). Moreover, waking elevation of the systolic blood pressure correlated with changes in all of the following cardiovascular variables during unloaded pedaling: heart rate (r = 0.69, P = 0.003), oxygen consumption (r = 0.73, P = 0.001), oxygen pulse (r = 0.62, P = 0.001), and rate pressure product (r = 0.64, P = 0.008), respectively. These observations indicate that individuals with prominent blood pressure elevation upon awakening also experience cardiovascular overload from slight physical activities.

  4. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature

    Directory of Open Access Journals (Sweden)

    Liu Gang

    2015-01-01

    Full Text Available High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were also carried out. The results show that: at the temperatures of 650 ∘C and 700 ∘C, the flow curves exhibit the power-law constitutive relation until peak stress is reached and the deformability is suitable for the HPGF process of Ti-3Al-2.5V alloy tube. The effects of pressurization path on the corner filling process and thickness profile are obvious. The high pressure inflow process can result in temperature difference between the straight wall area and corner area, which makes the thickness profile special. Besides, with the stepped pressurization path, the more constant filling rate and better thickness profile can be obtained.

  5. Genetic context determines susceptibility to intraocular pressure elevation in a mouse pigmentary glaucoma

    Directory of Open Access Journals (Sweden)

    Cosma Ioan M

    2006-07-01

    Full Text Available Abstract Background DBA/2J (D2 mice develop an age-related form of glaucoma. Their eyes progressively develop iris pigment dispersion and iris atrophy followed by increased intraocular pressure (IOP and glaucomatous optic nerve damage. Mutant alleles of the Gpnmb and Tyrp1 genes are necessary for the iris disease, but it is unknown whether alleles of other D2 gene(s are necessary for the distinct later stages of disease. We initiated a study of congenic strains to further define the genetic requirements and disease mechanisms of the D2 glaucoma. Results To further understand D2 glaucoma, we created congenic strains of mice on the C57BL/6J (B6 genetic background. B6 double-congenic mice carrying D2-derived Gpnmb and Tyrp1 mutations develop a D2-like iris disease. B6 single-congenics with only the Gpnmb and Tyrp1 mutations develop milder forms of iris disease. Genetic epistasis experiments introducing a B6 tyrosinase mutation into the congenic strains demonstrated that both the single and double-congenic iris diseases are rescued by interruption of melanin synthesis. Importantly, our experiments analyzing mice at ages up to 27 months indicate that the B6 double-congenic mice are much less prone to IOP elevation and glaucoma than are D2 mice. Conclusion As demonstrated here, the Gpnmb and Tyrp1 iris phenotypes are both individually dependent on tyrosinase function. These results support involvement of abnormal melanosomal events in the diseases caused by each gene. In the context of the inbred D2 mouse strain, the glaucoma phenotype is clearly influenced by more genes than just Gpnmb and Tyrp1. Despite the outward similarity of pigment-dispersing iris disease between D2 and the B6 double-congenic mice, the congenic mice are much less susceptible to developing high IOP and glaucoma. These new congenic strains provide a valuable new resource for further studying the genetic and mechanistic complexity of this form of glaucoma.

  6. High pressure-elevated temperature x-ray micro-computed tomography for subsurface applications.

    Science.gov (United States)

    Iglauer, Stefan; Lebedev, Maxim

    2018-06-01

    Physical, chemical and mechanical pore-scale (i.e. micrometer-scale) mechanisms in rock are of key importance in many, if not all, subsurface processes. These processes are highly relevant in various applications, e.g. hydrocarbon recovery, CO 2 geo-sequestration, geophysical exploration, water production, geothermal energy production, or the prediction of the location of valuable hydrothermal deposits. Typical examples are multi-phase flow (e.g. oil and water) displacements driven by buoyancy, viscous or capillary forces, mineral-fluid interactions (e.g. mineral dissolution and/or precipitation over geological times), geo-mechanical rock behaviour (e.g. rock compaction during diagenesis) or fines migration during water production, which can dramatically reduce reservoir permeability (and thus reservoir performance). All above examples are 3D processes, and 2D experiments (as traditionally done for micro-scale investigations) will thus only provide qualitative information; for instance the percolation threshold is much lower in 3D than in 2D. However, with the advent of x-ray micro-computed tomography (μCT) - which is now routinely used - this limitation has been overcome, and such pore-scale processes can be observed in 3D at micrometer-scale. A serious complication is, however, the fact that in the subsurface high pressures and elevated temperatures (HPET) prevail, due to the hydrostatic and geothermal gradients imposed upon it. Such HPET-reservoir conditions significantly change the above mentioned physical and chemical processes, e.g. gas density is much higher at high pressure, which strongly affects buoyancy and wettability and thus gas distributions in the subsurface; or chemical reactions are significantly accelerated at increased temperature, strongly affecting fluid-rock interactions and thus diagenesis and deposition of valuable minerals. It is thus necessary to apply HPET conditions to the aforementioned μCT experiments, to be able to mimic subsurface

  7. Intraocular pressure elevation precedes a phagocytosis decline in a model of pigmentary glaucoma [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Yalong Dang

    2018-04-01

    Full Text Available Background: Outflow regulation and phagocytosis are key functions of the trabecular meshwork (TM, but it is not clear how the two are related in secondary open angle glaucomas characterized by an increased particle load. We hypothesized that diminished TM phagocytosis is not the primary cause of early ocular hypertension and recreated pigment dispersion in a porcine ex vivo model. Methods: Sixteen porcine anterior chamber cultures received a continuous infusion of pigment granules (Pg, while 16 additional anterior chambers served as controls (C. Pressure transducers recorded the intraocular pressure (IOP. The phagocytic capacity of the trabecular meshwork was determined by fluorescent microspheres. Results: The baseline IOPs in Pg and C were similar (P=0.82. A significant IOP elevation occurred in Pg at 48, 120, and 180 hours (all P0.05. Conclusions: In this porcine model of pigmentary glaucoma, an IOP elevation occurs much earlier than when phagocytosis fails, suggesting that two separate mechanisms might be at work.

  8. A Pilot Study: Comparison of Arm Versus Ankle Noninvasive Blood Pressure Measurement at 2 Different Levels of Backrest Elevation.

    Science.gov (United States)

    Henley, Nicole; Quatrara, Beth D; Conaway, Mark

    2015-01-01

    Standard practice for obtaining noninvasive blood pressure includes arm blood pressure (BP) cuff placement at the level of the heart; however, some critical care patients cannot have BPs taken in their arm because of various conditions, and ankle BPs are frequently used as substitutes. The aim of this study was to determine if there was a significant variation between upper arm and ankle BP measurements at different backrest elevations with consideration of peripheral edema factors. After institutional review board approval was obtained, a pilot study was implemented to evaluate noninvasive BP measurements of the arm and ankle with backrest elevation at 0° and 30° in a population of medical intensive care unit patients. Participants served as their own controls and were randomly assigned to left- versus right-side BP readings. Data were also collected on presence of arm versus ankle edema. A total of 30 participants enrolled in the study and provided 120 BP measurements. Blood pressure readings were analyzed in terms of diastolic and systolic findings as well as backrest elevations and edema presence. Thirteen participants presented with either arm or ankle edema. There was a statistical difference between the systolic arm and ankle BP measurements in the 0° (P = .008) and 30° (P arm and ankle diastolic BP is greater for participants without ankle edema (P = .038, r = 0.54) than for participants with ankle edema (P = .650, r = 0.14), but it is not statistically significant (P = .47). Even though ankle BPs are often substituted for arm BPs when the arm is unable to be used, ankle BPs and arm BPs are not interchangeable. Adjustments in backrest elevation and considerations of edema do not normalize the differences. Blood pressures obtained from the ankle are significantly greater than those obtained from the arm. This information needs to be considered when arms are not available and legs are used as surrogates for the upper arm.

  9. Intracranial hemorrhage due to intracranial hypertension caused by the superior vena cava syndrome

    DEFF Research Database (Denmark)

    Bartek, Jiri; Abedi-Valugerdi, Golbarg; Liska, Jan

    2013-01-01

    We report a patient with intracranial hemorrhage secondary to venous hypertension as a result of a giant aortic pseudoaneurysm that compressed the superior vena cava and caused obstruction of the venous return from the brain. To our knowledge, this is the first patient reported to have...... an intracranial hemorrhage secondary to a superior vena cava syndrome. The condition appears to be caused by a reversible transient rise in intracranial pressure, as a result of compression of the venous return from the brain. Treatment consisted of surgery for the aortic pseudoaneurysm, which led...

  10. Complications corner: Anterior thoracic disc surgery with dural tear/CSF fistula and low-pressure pleural drain led to severe intracranial hypotension

    OpenAIRE

    Oudeman, Eline A.; Tewarie, Rishi D. S. Nandoe; J?bsis, G. Joost; Arts, Mark P.; Kruyt, Nyika D.

    2015-01-01

    Background: Thoracic disc surgery can lead to a life-threatening complication: intracranial hypotension due to a subarachnoid-pleural fistula. Case Description: We report a 63-year-old male with paraparesis due to multiple herniated thoracic discs, with compressive myelopathy. The patient required a circumferential procedure including a laminectomy/fusion followed by an anterior thoracic decompression to address both diffuse idiopathic skeletal hyperostosis (DISH) anteriorly and posterior...

  11. Intracranial hypotension and hypertension in children and adolescents.

    Science.gov (United States)

    Ozge, Aynur; Bolay, Hayrunnisa

    2014-07-01

    The specific aim of this review is to report the features of intracranial pressure changes [spontaneous intracranial hypotension (SIH) and idiopathic intracranial hypertension (IIH)] in children and adolescents, with emphasis on the presentation, diagnosis, and treatment modalities. Headache associated with intracranial pressure changes are relatively rare and less known in children and adolescents. SIH is a specific syndrome involving reduced intracranial pressure with orthostatic headache, frequently encountered connective tissue disorders, and a good prognosis with medical management, initial epidural blood patching, and sometimes further interventions may be required. IIH is an uncommon condition in children and different from the disease in adults, not only with respect to clinical features (likely to present with strabismus and stiff neck rather than headache or pulsatile tinnitus) but also different in outcome. Consequently, specific ICP changes of pediatric ages required specific attention both of exact diagnosis and entire management.

  12. Lifestyle Patterns Are Associated with Elevated Blood Pressure among Qatari Women of Reproductive Age: A Cross-Sectional National Study

    Directory of Open Access Journals (Sweden)

    Mohammed Al Thani

    2015-09-01

    Full Text Available Women of childbearing age are particularly vulnerable to the adverse effects of elevated blood pressure (BP, with dietary and lifestyle habits being increasingly recognized as important modifiable environmental risk factors for this condition. Using data from the National STEPwise survey conducted in Qatar in year 2012, we aimed to examine lifestyle patterns and their association with elevated BP among Qatari women of childbearing age (18–45 years. Socio-demographic, lifestyle, dietary, anthropometric and BP data were used (n = 747. Principal component factor analysis was applied to identify the patterns using the frequency of consumption of 13 foods/food groups, physical activity level, and smoking status. Multivariate logistic regression analyses were used to evaluate the association of the identified lifestyle patterns with elevated BP and to examine the socio-demographic correlates of these patterns. Three lifestyle patterns were identified: a “healthy” pattern characterized by intake of fruits, natural juices, and vegetables; a “fast food & smoking” pattern characterized by fast foods, sweetened beverages, and sweets, in addition to smoking; and a “traditional sedentary” pattern which consisted of refined grains, dairy products, and meat in addition to low physical activity. The fast food & smoking and the traditional & sedentary patterns were associated with an approximately 2-fold increase in the risk of elevated BP in the study population. The findings of this study highlight the synergistic effect that diet, smoking and physical inactivity may have on the risk of elevated BP among Qatari women.

  13. Lifestyle Patterns Are Associated with Elevated Blood Pressure among Qatari Women of Reproductive Age: A Cross-Sectional National Study.

    Science.gov (United States)

    Al Thani, Mohammed; Al Thani, Al Anoud; Al-Chetachi, Walaa; Al Malki, Badria; Khalifa, Shamseldin A H; Bakri, Ahmad Haj; Hwalla, Nahla; Nasreddine, Lara; Naja, Farah

    2015-09-09

    Women of childbearing age are particularly vulnerable to the adverse effects of elevated blood pressure (BP), with dietary and lifestyle habits being increasingly recognized as important modifiable environmental risk factors for this condition. Using data from the National STEPwise survey conducted in Qatar in year 2012, we aimed to examine lifestyle patterns and their association with elevated BP among Qatari women of childbearing age (18-45 years). Socio-demographic, lifestyle, dietary, anthropometric and BP data were used (n = 747). Principal component factor analysis was applied to identify the patterns using the frequency of consumption of 13 foods/food groups, physical activity level, and smoking status. Multivariate logistic regression analyses were used to evaluate the association of the identified lifestyle patterns with elevated BP and to examine the socio-demographic correlates of these patterns. Three lifestyle patterns were identified: a "healthy" pattern characterized by intake of fruits, natural juices, and vegetables; a "fast food & smoking" pattern characterized by fast foods, sweetened beverages, and sweets, in addition to smoking; and a "traditional sedentary" pattern which consisted of refined grains, dairy products, and meat in addition to low physical activity. The fast food & smoking and the traditional & sedentary patterns were associated with an approximately 2-fold increase in the risk of elevated BP in the study population. The findings of this study highlight the synergistic effect that diet, smoking and physical inactivity may have on the risk of elevated BP among Qatari women.

  14. An Experimental Investigation on the NO and CO Emission Characteristics of a Swirl Convergent-Divergent Nozzle at Elevated Pressure

    Directory of Open Access Journals (Sweden)

    Zhongya Xi

    2018-05-01

    Full Text Available The behavior of the pollutants NO and CO at elevated combustor pressure are of special importance due to the continuing trend toward developing engines operating at higher pressure ratios to yield higher thermal efficiency. An experiment was performed to examine the NO and CO emissions for a swirl convergent-divergent nozzle at elevated pressure. The NO and CO correlations were obtained. Meanwhile, the flame length, exhaust gas oxygen concentration, exit temperature and global flame residence time were also determined to analyze the NO and CO emission characteristics. The results showed that, with the increase in combustor pressure P, flame length decreased proportionally to P−0.49; exit O2 volume fraction increased and exit temperature was reduced. The global flame residence time decreased proportionally to P−0.43. As pressure increased, The NO and Emission Index of NO (EINO levels decreased proportionally to P−0.53 and P−0.6 respectively, which is mainly attributed to the influence of global flame residence time; the NO and EINO increased almost proportionally with the increase in global flame residence time. The EINO scaling EINO (ρue/d was proportional to Fr0.42, which indicated that compared with pure fuel, the fuel diluted with primary air can cause a decrease in the exponent of the Fr power function. At higher pressure, the CO and Emission Index of CO (EICO decreased proportionally to P−0.35 and P−0.4, respectively, due to the increased unburned methane and high pressure which accelerated chemical reaction kinetics to promote the conversion of CO to CO2.

  15. Genus Zero Graph Segmentation: Estimation of Intracranial Volume

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Thorup, Signe Strann; Paulsen, Rasmus Reinhold

    2013-01-01

    The intracranial volume (ICV) in children with premature fusion of one or more sutures in the calvaria is of interest due to the risk of increased intracranial pressure. Challenges for automatic estimation of ICV include holes in the skull e.g. the foramen magnum and fontanelles. In this paper, we...

  16. Idiopathic intracranial hypertension with altered consciousness in a ...

    African Journals Online (AJOL)

    Idiopathic intracranial hypertension (IIH) is a clinical condition of increased intracranial pressure (ICP) without an obvious underlying pathological brain lesion. It is usually characterized by headache, neck pain, vomiting, visual disturbances, papilledema, cranial nerve palsy or a combination of these signs and symptoms.

  17. Genus zero graph segmentation: Estimation of intracranial volume

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Thorup, Signe Strann; Paulsen, Rasmus Reinhold

    2014-01-01

    The intracranial volume (ICV) in children with premature fusion of one or more sutures in the calvaria is of interest due to the risk of increased intracranial pressure. Challenges for automatic estimation of ICV include holes in the skull e.g. the foramen magnum and fontanelles. In this paper, w...

  18. IIH with normal CSF pressures?

    Directory of Open Access Journals (Sweden)

    Soh Youn Suh

    2013-01-01

    Full Text Available Idiopathic intracranial hypertension (IIH is a condition of raised intracranial pressure (ICP in the absence of space occupying lesions. ICP is usually measured by lumbar puncture and a cerebrospinal fluid (CSF pressure above 250 mm H 2 O is one of the diagnostic criteria of IIH. Recently, we have encountered two patients who complained of headaches and exhibited disc swelling without an increased ICP. We prescribed acetazolamide and followed both patients frequently; because of the definite disc swelling with IIH related symptoms. Symptoms and signs resolved in both patients after they started taking acetazolamide. It is generally known that an elevated ICP, as measured by lumbar puncture, is the most important diagnostic sign of IIH. However, these cases caution even when CSF pressure is within the normal range, that suspicion should be raised when a patient has papilledema with related symptoms, since untreated papilledema may cause progressive and irreversible visual loss.

  19. Association of elevated blood pressure with low distress and good quality of life: results from the nationwide representative German Health Interview and Examination Survey for Children and Adolescents.

    Science.gov (United States)

    Berendes, Angela; Meyer, Thomas; Hulpke-Wette, Martin; Herrmann-Lingen, Christoph

    2013-05-01

    Quality of life is often impaired in patients with known hypertension, but it is less or not at all reduced in people unaware of their elevated blood pressure. Some studies have even shown less self-rated distress in adults with elevated blood pressure. In this substudy of the nationwide German Health Interview and Examination Survey for Children and Adolescents (KIGGS), we addressed the question whether, also in adolescents, hypertensive blood pressure is linked to levels of distress and quality of life. Study participants aged 11 to 17 years (N = 7688) received standardized measurements of blood pressure, quality of life (using the Children's Quality of Life Questionnaire), and distress (Strengths and Difficulties Questionnaire). Elevated blood pressure was twice as frequent as expected, with 10.7% (n = 825) above published age-, sex- and height-adjusted 95th percentiles. Hypertensive participants were more likely to be obese and to report on adverse health behaviors, but they showed better academic success than did normotensive participants. Elevated blood pressure was significantly and positively associated with higher self- and parent-rated quality of life (for both, p ≤ .006), less hyperactivity (for both, p parent-rated emotional (p pressure to better well-being and low distress can partly be explained by the absence of confounding physical comorbidity and the unawareness of being hypertensive. It also corresponds to earlier research suggesting a bidirectional relationship with repressed emotions leading to elevated blood pressure and, furthermore, elevated blood pressure serving as a potential stress buffer.

  20. Elevated Blood Pressure and Obesity in Childhood: A Cross-Sectional Evaluation of 4,609 Schoolchildren

    Directory of Open Access Journals (Sweden)

    Caroline Filla Rosaneli

    2014-09-01

    Full Text Available Background: The incidence of obesity in children is increasing worldwide, primarily in urbanized, high-income countries, and hypertension development is a detrimental effect of this phenomenon. Objective: In this cross-sectional study, we evaluated the prevalence of excess weight and its association with high blood pressure (BP in schoolchildren. Methods: Here 4,609 male and female children, aged 6 to 11 years, from 24 public and private schools in Maringa, Brazil, were evaluated. Nutritional status was assessed by body mass index (BMI according to cutoff points adjusted for sex and age. Blood pressure (BP levels above 90th percentile for gender, age and height percentile were considered elevated. Results: The prevalence of excess weight among the schoolchildren was 24.5%; 16.9% were overweight, and 7.6% were obese. Sex and socioeconomic characteristics were not associated with elevated BP. In all age groups, systolic and diastolic BP correlated with BMI and waist and hip measurements, but not with waist-hip ratio. The prevalence of elevated BP was 11.2% in eutrophic children, 20.6% in overweight children [odds ratio (OR, 1.99; 95% confidence interval (CI, 1.61-2.45], and 39.7% in obese children (OR, 5.4; 95% CI, 4.23-6.89. Conclusion: Obese and overweight children had a higher prevalence of elevated BP than normal-weight children. Our data confirm that the growing worldwide epidemic of excess weight and elevated BP in schoolchildren may also be ongoing in Brazil.

  1. Variables predicting elevated portal pressure in alcoholic liver disease. Results of a multivariate analysis

    DEFF Research Database (Denmark)

    Krogsgaard, K; Christensen, E; Gluud, C

    1987-01-01

    In 46 alcoholic patients the association of wedged-to-free hepatic-vein pressure with other variables (clinical, histologic, hemodynamic, and liver function data) was studied by means of multiple regression analysis, taking the wedged-to-free hepatic-vein pressure as the dependent variable. Four ...

  2. Effects of elevated temperature and pore pressure on the mechanical behavior of Bullfrog tuff

    International Nuclear Information System (INIS)

    Olsson, W.A.

    1982-02-01

    Samples of the Bullfrog Member of the Crater Flat Tuff from the depth interval 758.9 to 759.2 m in hole USW-G1 on the Nevada Test Site were tested in triaxial compression. Test conditions were: (1) effective confining pressure to 20 MPa; (2) temperature of 200 0 C; (3) both dry and with pore water pressures from 3.4 to 5 MPa; and (4) a strain-rate of 10 -4 /s. The results suggest that the presence of water causes the strength to decrease. In addition, the brittle-ductile transition pressure for this rock was found to be about 15 MPa, regardless of saturation. Below this pressure deformation is characterized by unstable stress drops and the development of a single fracture, and above this pressure deformation is stable and distributed more uniformly throughout the sample

  3. Determining pH at elevated pressure and temperature using in situ ¹³C NMR.

    Science.gov (United States)

    Surface, J Andrew; Wang, Fei; Zhu, Yanzhe; Hayes, Sophia E; Giammar, Daniel E; Conradi, Mark S

    2015-02-03

    We have developed an approach for determining pH at elevated pressures and temperatures by using (13)C NMR measurements of inorganic carbon species together with a geochemical equilibrium model. The approach can determine in situ pH with precision better than 0.1 pH units at pressures, temperatures, and ionic strengths typical of geologic carbon sequestration systems. A custom-built high pressure NMR probe was used to collect (13)C NMR spectra of (13)C-labeled CO2 reactions with NaOH solutions and Mg(OH)2 suspensions at pressures up to 107 bar and temperatures of 80 °C. The quantitative nature of NMR spectroscopy allows the concentration ratio [CO2]/[HCO3(-)] to be experimentally determined. This ratio is then used with equilibrium constants calculated for the specific pressure and temperature conditions and appropriate activity coefficients for the solutes to calculate the in situ pH. The experimentally determined [CO2]/[HCO3(-)] ratios agree well with the predicted values for experiments performed with three different concentrations of NaOH and equilibration with multiple pressures of CO2. The approach was then applied to experiments with Mg(OH)2 slurries in which the change in pH could track the dissolution of CO2 into solution, rapid initial Mg(OH)2 dissolution, and onset of magnesium carbonate precipitation.

  4. Breakfast skippers display a disrupted cortisol rhythm and elevated blood pressure

    Science.gov (United States)

    Chronic stress and over-activity in the hypothalamic-pituitary-adrenal (HPA) axis may link breakfast skipping and poor cardiometabolic health. Missing the first major meal of the day in rodents prolongs elevated circulating corticosterone at a time when it’s normally decreasing. To extend these fi...

  5. Spontaneous intracranial hypotension.

    LENUS (Irish Health Repository)

    Fullam, L

    2012-01-31

    INTRODUCTION: Spontaneous\\/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

  6. NOISY INTRACRANIAL TUMORS

    NARCIS (Netherlands)

    VANDOOREN, BTH; VANBRUGGEN, AC; MOOIJ, JJA; HEW, JM; JOURNEE, HL

    1994-01-01

    Transorbital sound recordings were obtained from 21 patients with intracranial tumours, 28 patients with intracranial aneurysms and 20 control patients. The group of patients with tumours consisted of 12 patients with gliomas, of whom 6 had low-grade gliomas and 6 had high-grade gliomas, and 9

  7. Characterisation of a Planar Solid Oxide Cell Stack Operated at Elevated Pressure

    DEFF Research Database (Denmark)

    Jensen, Søren Højgaard; Graves, Christopher R.; Chen, Ming

    2016-01-01

    As the global and local energy production becomes more dependent on intermittent renewable sources like wind and solar, efficient and reversible conversion of electricity to storable fuels becomes increasingly important. Solid oxide cells (SOCs) are interesting in this context since they can...... be operated either as electrolysers (SOEC) to convert electricity to fuels such as hydrogen or methane, and as fuel cells (SOFC) to convert fuels to electricity. Both productivity and conversion efficiency can be improved if the SOC operation pressure can be increased from ambient pressure to 10-30 bar. Here...... and heat exchangers is analyzed and the expected impact of pressurization on the hydrogen production cost is evaluated....

  8. Variation in monitoring and treatment policies for intracranial hypertension in traumatic brain injury

    DEFF Research Database (Denmark)

    Cnossen, Maryse C; Huijben, Jilske A; van der Jagt, Mathieu

    2017-01-01

    BACKGROUND: No definitive evidence exists on how intracranial hypertension should be treated in patients with traumatic brain injury (TBI). It is therefore likely that centers and practitioners individually balance potential benefits and risks of different intracranial pressure (ICP) management......, and it was pilot-tested in 16 centers. The questionnaire was sent to 68 neurotrauma centers participating in the Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. RESULTS: The survey was completed by 66 centers (97% response rate). Centers were mainly academic....... There was no consensus on other indications or on peri-insertion precautions. We found wide variation in the use of first- and second-tier treatments for elevated ICP. Approximately half of the centers were classified as using a relatively aggressive approach to ICP monitoring and treatment (n = 32, 48%), whereas...

  9. Impact of CO2 on Intracranial Hypertension in Spaceflight. Visual Impairment and Intracranial Hypertension: An Emerging Spaceflight Risk [Part 1 and 2

    Science.gov (United States)

    Fogarty, Jennifer A.; Polk, James D.; Tarver, William J.; Gibson, Charles R.; Sargsyan, Ashot E.; Taddeo, Terrance A.; Alexander, David J.; Otto, Christian A.

    2010-01-01

    A. CO2 - Acute: Given the history of uneven removal of CO2 from spacecraft areas, there is a history of acute illness that impacts short-term health and performance. 1) Acute CO2 symptoms occur in space flight due to a combination of CO2 scrubbing limitations, microgravity-related lack of convection, and possibly interaction with microgravity-related physiological changes. 2) Reported symptoms mainly include headaches, malaise, and lethargy. Symptoms are treatable with analgesics, rest, temporarily increasing scrubbing capability, and breathing oxygen. This does not treat the underlying pathology. 3)ld prevent occurrence of symptoms. B. CO2 - Chronic: Given prolonged exposure to elevated CO2 levels, there is a history that the long-term health of the crew is impacted. 1) Chronic CO2 exposures occur in space flight due to a combination of CO2 scrubbing limitations and microgravity-related lack of convection, with possible contribution from microgravity-related physiological changes. 2) Since acute symptoms are experienced at levels significantly lower than expected, there are unidentified long-term effects from prolonged exposure to elevated CO2 levels on orbit. There have been long term effects seen terrestrially and research needed to further elucidate long term effects on orbit. 3) Recommended disposition: Research required to further elucidate long term effects. In particular, elucidation of the role of elevated CO2 on various levels of CO2 vasodilatation of intracranial blood vessels and its potential contribution to elevation of intracranial pressure.

  10. Home Blood Pressure Monitoring as an Alternative to Confirm Diagnoses of Hypertension in Adolescents with Elevated Office Blood Pressure from a Brazilian State Capital

    Science.gov (United States)

    Póvoa, Thaís Inacio Rolim; Jardim, Thiago Veiga; Carneiro, Carolina de Souza; Ferreira, Vanessa Roriz; Mendonça, Karla Lorena; de Morais, Polyana Resende Silva; Nascente, Flávia Miquetichuc Nogueira; de Souza, Weimar Kunz Sebba Barroso; Sousa, Ana Luiza Lima; Jardim, Paulo César Brandão Veiga

    2017-01-01

    Background Regional differences of using home blood pressure monitoring (HBPM) as an alternative to ambulatory blood pressure monitoring (ABPM) in hypertensive adolescents are unknown. Objectives Define if HBPM is an option to confirm diagnoses of hypertension in adolescents from a Brazilian capital with elevated office blood pressure (BP). Methods Adolescents (12-18years) from public and private schools with BP > 90th percentile were studied to compare and evaluate the agreement among office BP measurements, HBPM and ambulatory BP monitoring. Office BP measurements, HBPM and ABPM were performed according to guidelines recommendations. Semi-automatic devices were used for BP measurements. Values of p ABPM values (120.3 ± 12.6 mmHg x 121.5 ± 9.8 mmHg - p = 0.111 and 69.4 ± 7.7 mmHg x 70.2 ± 6.6 mmHg - p = 0.139) and lower than the office measurement values (127.3 ± 13.8 mmHg over 74.4 ± 9.5 mmHg - p ABPM. Conclusions HBPM is an option to confirm diagnoses of hypertension in adolescents from a Brazilian state capital with elevated office BP and can be used as an alternative to ABPM. PMID:28793045

  11. Intracranial atherosclerosis: current concepts.

    Science.gov (United States)

    Arenillas, Juan F

    2011-01-01

    The most relevant ideas discussed in this article are described here. Intracranial atherosclerotic disease (ICAD) represents the most common cause of ischemic stroke worldwide. Its importance in whites may have been underestimated. New technical developments, such as high-resolution MRI, allow direct assessment of the intracranial atherosclerotic plaque, which may have a profound impact on ICAD diagnosis and therapy in the near future. Early detection of ICAD may allow therapeutic intervention while the disease is still asymptomatic. The Barcelonès Nord and Maresme Asymptomatic Intracranial Atherosclerosis Study is presented here. The main prognostic factors that characterize the patients who are at a higher risk for ICAD recurrence are classified and discussed. The best treatment for ICAD remains to be established. The Stenting Versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Study is currently ongoing to address this crucial issue. These and other topics will be discussed at the Fifth International Intracranial Atherosclerosis Conference (Valladolid, Spain, autumn 2011).

  12. Elevated blood pressure in offspring of rats exposed to diverse chemicals during pregnancy

    Science.gov (United States)

    Adverse intrauterine environments are associated with increased risk of later disease, including cardiovascular disease and hypertension. As a potential bioindicator of such an adverse environment, we measured blood pressure (BP), renal nephron endowment, renal glucocorticoid rec...

  13. Study on nitrogen diluted propane-air premixed flames at elevated pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Tang Chenglong; Zheng Jianjun [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Huang Zuohua, E-mail: zhhuang@mail.xjtu.edu.c [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Wang Jinhua [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2010-02-15

    Using a high pressure constant volume combustion vessel, the propagation and morphology of spark-ignited outwardly expanding nitrogen diluted propane-air flames were imaged and recorded by schlieren photography and high-speed digital camera. The unstretched laminar burning velocities and Markstein lengths were subsequently determined over wide range of initial temperatures, initial pressures and nitrogen dilution ratios. Two recently developed mechanisms were used to predict the reference laminar burning velocity. The results show that the measured unstretched laminar burning velocities agree well with those in the literature and the computationally predicted results. The flame images show that the diffusional-thermal instability is promoted as the mixture becomes richer, and the hydrodynamic instability is increased with the increase of the initial pressure and it is decreased with the increase of dilution ratio. The normalized laminar burning velocities show a linear correlation with respect to the dilution ratio, indicating that the effect of nitrogen dilution is more obvious at higher pressures.

  14. Measurement of amino acid levels in the vitreous humor of rats after chronic intraocular pressure elevation or optic nerve transection.

    Science.gov (United States)

    Levkovitch-Verbin, Hana; Martin, Keith R G; Quigley, Harry A; Baumrind, Lisa A; Pease, Mary Ellen; Valenta, Danielle

    2002-10-01

    To investigate whether the levels of free amino acids and protein in the vitreous of rat eyes are altered with chronic intraocular pressure (IOP) elevation or after optic nerve transection. The concentrations of 20 amino acids in the vitreous humor were measured by high-performance liquid chromatography in both eyes of 41 rats with unilateral IOP elevation induced by translimbal photocoagulation. Eyes were studied 1 day and 1, 2, 4, and 9 weeks after initial IOP elevation. The same amino acids were measured in 41 rats 1 day and 2, 4, and 9 weeks after unilateral transection of the orbital optic nerve. The intravitreal protein level was assayed in additional 22 rats with IOP elevation and 12 rats after nerve transection. Two masked observers evaluated the amount of optic nerve damage with a semiquantitative, light-microscopic technique. In rats with experimental glaucoma, amino acid concentrations were unchanged 1 day after treatment. At 1 week, 4 of 20 amino acids (aspartate, proline, alanine, and lysine) were higher than in control eyes ( 0.05). Vitreous protein level was significantly higher in glaucomatous eyes than their paired controls at 1 day ( 0.01).

  15. Morning pulse pressure is associated more strongly with elevated albuminuria than systolic blood pressure in patients with type 2 diabetes mellitus: post hoc analysis of a cross-sectional multicenter study.

    Science.gov (United States)

    Ushigome, Emi; Fukui, Michiaki; Hamaguchi, Masahide; Matsumoto, Shinobu; Mineoka, Yusuke; Nakanishi, Naoko; Senmaru, Takafumi; Yamazaki, Masahiro; Hasegawa, Goji; Nakamura, Naoto

    2013-09-01

    Recently, focus has been directed toward pulse pressure as a potentially independent risk factor for micro- and macrovascular disease. This study was designed to examine the relationship between pulse pressure taken at home and elevated albuminuria in patients with type 2 diabetes. This study is a post hoc analysis of a cross-sectional multicenter study. Home blood pressure measurements were performed for 14 consecutive days in 858 patients with type 2 diabetes. We investigated the relationship between systolic blood pressure or pulse pressure in the morning or in the evening and urinary albumin excretion using univariate and multivariate analyses. Furthermore, we measured area under the receiver-operating characteristic curve (AUC) to compare the ability to identify elevated albuminuria, defined as urinary albumin excretion equal to or more than 30 mg/g creatinine, of systolic blood pressure or pulse pressure. Morning systolic blood pressure (β=0.339, Ppressure (β=0.378, PAUC for elevated albuminuria in morning systolic blood pressure and morning pulse pressure were 0.668 (0.632-0.705; PAUC of morning pulse pressure was significantly greater than that of morning systolic blood pressure (P=0.040). Our findings implicate that morning pulse pressure is associated with elevated albuminuria in patients with type 2 diabetes, which suggests that lowering morning pulse pressure could prevent the development and progression of diabetic nephropathy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. The structure of MgO-SiO2 glasses at elevated pressure.

    Science.gov (United States)

    Wilding, Martin; Guthrie, Malcolm; Kohara, Shinji; Bull, Craig L; Akola, Jaakko; Tucker, Matt G

    2012-06-06

    The magnesium silicate system is an important geophysical analogue and neutron diffraction data from glasses formed in this system may also provide an initial framework for understanding the structure-dependent properties of related liquids that are important during planetary formation. Neutron diffraction data collected in situ for a single composition (38 mol% SiO(2)) magnesium silicate glass sample shows local changes in structure as pressure is increased from ambient conditions to 8.6 GPa at ambient temperature. A method for obtaining the fully corrected, total structure factor, S(Q), has been developed that allows accurate structural characterization as this weakly scattering glass sample is compressed. The measured S(Q) data indicate changes in chemical ordering with pressure and the real-space transforms show an increase in Mg-O coordination number and a distortion of the local environment around magnesium ions. We have used reverse Monte Carlo methods to compare the high pressure and ambient pressure structures and also compare the high pressure form with a more silica-poor glass (Mg(2)SiO(4)) that represents the approach to a more dense, void-free and topologically ordered structure. The Mg-O coordination number increases with pressure and we also find that the degree of continuous connectivity of Si-O bonds increases via a collapse of interstices.

  17. Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility.

    Science.gov (United States)

    Chintalapudi, Sumana R; Maria, Doaa; Di Wang, Xiang; Bailey, Jessica N Cooke; Hysi, Pirro G; Wiggs, Janey L; Williams, Robert W; Jablonski, Monica M

    2017-11-24

    Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with known sequence variants, we are able to determine that the intraocular pressure-lowering effect of pregabalin is dependent on the Cacna2d1 haplotype. Using human genome-wide association study (GWAS) data, evidence for association of a CACNA2D1 single-nucleotide polymorphism and primary open angle glaucoma is found. Importantly, these results demonstrate that our systems genetics approach represents an efficient method to identify genetic variation that can guide the selection of therapeutic targets.

  18. Balancing Model Performance and Simplicity to Predict Postoperative Primary Care Blood Pressure Elevation.

    Science.gov (United States)

    Schonberger, Robert B; Dai, Feng; Brandt, Cynthia A; Burg, Matthew M

    2015-09-01

    Because of uncertainty regarding the reliability of perioperative blood pressures and traditional notions downplaying the role of anesthesiologists in longitudinal patient care, there is no consensus for anesthesiologists to recommend postoperative primary care blood pressure follow-up for patients presenting for surgery with an increased blood pressure. The decision of whom to refer should ideally be based on a predictive model that balances performance with ease-of-use. If an acceptable decision rule was developed, a new practice paradigm integrating the surgical encounter into broader public health efforts could be tested, with the goal of reducing long-term morbidity from hypertension among surgical patients. Using national data from US veterans receiving surgical care, we determined the prevalence of poorly controlled outpatient clinic blood pressures ≥140/90 mm Hg, based on the mean of up to 4 readings in the year after surgery. Four increasingly complex logistic regression models were assessed to predict this outcome. The first included the mean of 2 preoperative blood pressure readings; other models progressively added a broad array of demographic and clinical data. After internal validation, the C-statistics and the Net Reclassification Index between the simplest and most complex models were assessed. The performance characteristics of several simple blood pressure referral thresholds were then calculated. Among 215,621 patients, poorly controlled outpatient clinic blood pressure was present postoperatively in 25.7% (95% confidence interval [CI], 25.5%-25.9%) including 14.2% (95% CI, 13.9%-14.6%) of patients lacking a hypertension history. The most complex prediction model demonstrated statistically significant, but clinically marginal, improvement in discrimination over a model based on preoperative blood pressure alone (C-statistic, 0.736 [95% CI, 0.734-0.739] vs 0.721 [95% CI, 0.718-0.723]; P for difference 1 of 4 patients (95% CI, 25

  19. Does elevating image receptor increase breast receptor footprint and improve pressure balance?

    International Nuclear Information System (INIS)

    Smith, H.; Szczepura, K.; Mercer, C.; Maxwell, A.; Hogg, P.

    2015-01-01

    There is no consensus in the literature regarding the image receptor (IR) position for the cradio-caudal projection in mammography. Some literature indicates the IR should be positioned to the infra mammary fold (IMF); other literature suggests the IR be raised 2 cm relative to the IMF. Using 16 female volunteers (32 breasts) and a pressure sensitive mat we investigated breast footprint and pressure balance with IR at IMF and IR 2 cm above the IMF. Breast area on IR and paddle and interface pressure between IR/breast and paddle/breast were recorded. A uniformity index (UI) gave a measure of pressure balance between IR/breast and paddle/breast. IR breast footprint increases significantly by 13.81 cm 2 (p < 0.02) when IR is raised by 2 cm. UI reduces from 0.4 to 0.00 (p = 0.04) when positioned at IMF +2 cm demonstrating an improved pressure balance. Practitioners should consider raising the IR by 2 cm relative to the IMF in clinical practice. Further work is suggested to investigate the effects of practitioner variability and breast asymmetry. - Highlights: • Experimental study. • 16 female volunteers/32 breasts. • Compares two methods of conducting the cranio-caudal project. • Provides sufficient evidence to indicate which method is likely to be superior. • Has value to clinical mammography.

  20. Interfacial tension measurement between CO2 and brines under high temperature and elevated pressure conditions

    Science.gov (United States)

    Li, X.; Boek, E. S.; Maitland, G. C.; Trusler, J. P. M.

    2012-04-01

    We have investigated the dependence of interfacial tension of (CO2 + brine) on temperature, pressure and salinity (including both salt type and molality) over the range of conditions applicable to CO2 storage in saline aquifers. The study covered a wide range of measurements of the interfacial tensions between carbon dioxide and (NaCl + KCl)(aq), CaCl2(aq), MgCl2(aq), Na2SO4(aq), KHCO3(aq), NaHCO3(aq) and two laboratory constructed brines with molality ranging from (0.3 to 5.0) mol·kg-1. The measurements were made at temperatures between (298 and 448) K at various pressures up to 50 MPa, using the pendant drop method in a high-pressure view cell filled with water-saturated CO2. The drop to be imaged was created by injecting brine from a high-pressure syringe pump into a capillary sealed through the top of the cell. The expanded uncertainties of the experimental state variables at 95 % confidence are +0.05 K in temperature and +70 kPa in pressure. For the interfacial tension, the overall expanded relative uncertainty at 95 % confidence was +1.6%. The experimental results show that interfacial tension for all the systems increases linearly with molality, indicating that relatively few measurements and simple interpolation procedures are adequate for describing this property accurately over wide ranges of conditions.

  1. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    International Nuclear Information System (INIS)

    Swindeman, R.W.; Brinkman, C.R.

    1981-01-01

    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X

  2. Characterization of a Planar Solid Oxide Cell Stack Operated at Elevated Pressure

    DEFF Research Database (Denmark)

    Jensen, Søren Højgaard; Graves, Christopher R.; Chen, Ming

    2016-01-01

    As global and local energy production becomes more dependent on intermittent renewable sources like wind and solar, efficient and reversible conversion of electricity to storable fuels becomes increasingly important. Solid oxide cells (SOCs) are interesting in this context since they can...... be operated either as electrolyzers (SOEC) to convert electricity to fuels such as hydrogen or methane, and as fuel cells (SOFC) to convert fuels to electricity. Both productivity and conversion efficiency can be improved if the SOC operation pressure can be increased from ambient pressure to 10–30 bar...... in this paper. Additionally, the expected impact on the hydrogen production efficiency and cost is discussed....

  3. System and process for capture of acid gasses at elevated pressure from gaseous process streams

    Science.gov (United States)

    Heldebrant, David J.; Koech, Phillip K.; Linehan, John C.; Rainbolt, James E.; Bearden, Mark D.; Zheng, Feng

    2016-09-06

    A system, method, and material that enables the pressure-activated reversible chemical capture of acid gasses such as CO.sub.2 from gas volumes such as streams, flows or any other volume. Once the acid gas is chemically captured, the resulting product typically a zwitterionic salt, can be subjected to a reduced pressure whereupon the resulting product will release the captures acid gas and the capture material will be regenerated. The invention includes this process as well as the materials and systems for carrying out and enabling this process.

  4. Idiopathic intracranial hypertension and transverse sinus stenoses

    DEFF Research Database (Denmark)

    Skyrman, Simon; Fytagoridis, Anders; Andresen, Morten

    2013-01-01

    An 18-year-old woman was diagnosed with idiopathic intracranial hypertension (IIH) and bilateral transverse sinus stenoses (TSS), after presenting with papilledema and decreased visual acuity. Lumbar puncture revealed an opening pressure of >60 cm H2O. MRI showed bilateral TSS believed to be asso...

  5. Intracranial hypertension in 2 children with marfan syndrome

    NARCIS (Netherlands)

    Hilhorst-Hofstee, Yvonne; Kroft, Lucia J. M.; Pals, Gerard; van Vugt, Jeroen P. P.; Overweg-Plandsoen, Wouterina C. G.

    2008-01-01

    Two unrelated children with Marfan syndrome presented with recurrent intracranial hypertension. Both children complained of headache, nausea, and vomiting and one of them had papilledema. Both had increased cerebrospinal fluid pressure, and their complaints disappeared after lumbar puncture.

  6. Non-linearity parameter of binary liquid mixtures at elevated pressures

    Indian Academy of Sciences (India)

    parameter B/A of four binary liquid mixtures using Tong and Dong equation at high pressures and .... in general as regular or ideal as no recognized association takes place between the unlike molecules. In this case ... Using the definition and.

  7. Interactions of hydrogen with graphite at low pressure and elevated temperature

    International Nuclear Information System (INIS)

    Hoinkis, E.

    1991-03-01

    The plasma facing components of the vacuum chamber for thermonuclear fusion experiments are clad with graphite. Recycling of gases affects the plasma properties, and the tritium quantity accumulated in the graphite during the operation of Tokamaks with DT must be known. An adsorption isotherm for deuterium on the nuclear grade graphitic Matrix A3-3 was measured by using a volumetric method at 1173 K at pressures c = 2.5 eV/D 2 using Fowler's equation and isotherms were calculated for this E c value. These isotherms predict saturation of the adsorption sites in graphite at T D2 > 0.1 Pa. At T > 1173 K and P D2 -2 Pa the adsorbed quantity is less than 1% of the saturation level. The release kinetics of deuterium was measured at temperatures uo to 2000 K. D 2 desorption commenced at 1170 K. The maximum of the release rate is observed at T p = 1770 K. A Lennard-Jones potential energy diagram was calculated, which suggests a C-H bond energy E b ≅ 3.4 eV/D and an activation energy of desorption E d ≅ 4 eV/D 2 . The partial pressures of hydrocarbons C n ≤3 H m in equilibrium with graphite were calculated. At total pressures -2 Pa the partial pressures of these hydrocarbons are less than 10 -7 Pa in the temperature range 600-1500 K. (orig./MM)

  8. Noise exposure in occupational setting associated with elevated blood pressure in China

    Directory of Open Access Journals (Sweden)

    Shuchang Chen

    2017-01-01

    Full Text Available Abstract Background Hypertension is the primary out-auditory adverse outcome caused due to occupational noise exposure. This study investigated the associations of noise exposure in an occupational setting with blood pressure and risk of hypertension. Methods A total of 1,390 occupational noise-exposed workers and 1399 frequency matched non-noise-exposed subjects were recruited from a cross-sectional survey of occupational noise-exposed and the general population, respectively. Blood pressure was measured using a mercury sphygmomanometer following a standard protocol. Multiple logistic regression was used to calculate the odds ratio (OR and 95% confidence interval (CI of noise exposure adjusted by potential confounders. Results Noise-exposed subjects had significantly higher levels of systolic blood pressure(SBP (125.1 ± 13.9 mm Hg and diastolic blood pressure (DBP (77.6 ± 10.7 mm Hg than control subjects (SBP: 117.2 ± 15.7 mm Hg, DBP: 70.0 ± 10.5 mm Hg (P  0.05. Conclusions Occupational noise exposure was associated with higher levels of SBP, DBP, and the risk of hypertension. These findings indicate that effective and feasible measures should be implemented to reduce the risk of hypertension caused by occupational noise exposure.

  9. Maxillary sinus floor elevation via crestal approach: the evolution of the hydraulic pressure technique.

    Science.gov (United States)

    Lopez, Michele Antonio; Andreasi Bassi, Mirko; Confalone, Luca; Carinci, Francesco

    2014-01-01

    The current study describes an innovative protocol for the surgical maxillary sinus augmentation via a crestal approach that uses hydraulic pressure to lift the Schneiderian membrane and simultaneously fill the subantral space with a biomaterial for bone regeneration (nanocrystalline hydroxyapatite in aqueous solution). The technique in question combines the advantages of large amounts of grafted biomaterial with reduced trauma, high precision, and predictability.

  10. Performance and metallography of a uranium tritide bed operated at elevated temperatures and tritium pressures

    International Nuclear Information System (INIS)

    Mote, M.W. Jr.; Mintz, J.M.

    1986-12-01

    A uranium gettering bed was cycled between room temperature/zero pressure and 600C/275 psi (D 2 ) for 210 cycles over a period of 8 months. Metallographic examination of the hardware revealed an acceptable amount of reaction between the uranium and the stainless steel container. This exposure is estimated to represent about ten years of normal use

  11. Passive control of thermoacoustic instabilities in swirl-stabilized combustion at elevated pressures

    Directory of Open Access Journals (Sweden)

    L Justin Williams

    2016-09-01

    Full Text Available In this study, a porous insert is placed at the dump plane of a swirl-stabilized lean premixed combustor to passively suppress thermoacoustic instabilities. The diffuser-shaped annular ring of porous inert material influences the turbulent flow field directly, including recirculation zones and vortical and/or shear layer structures to passively control the acoustic performance of the combustor. The porous inert material is made of silicon carbide–hafnium carbide coated, high-strength, high-temperature-resistant open-cell foam materials. In this study, the porous insert concept is investigated at above-ambient operating pressures to demonstrate its suitability for practical combustion applications. Experiments are conducted in quartz and metal combustors, without and with the porous insert while varying operating pressure, equivalence ratio, and reactant flow rate. Measurements show that the porous insert, and consequent changes in the combustor flow field, decrease the sound pressure levels at the frequency of combustion instability at all operating conditions investigated in this study. The porous insert also decreases the broadband combustion noise, i.e. the measured sound pressure levels over a wide frequency range.

  12. Models of WO x films growth during pulsed laser deposition at elevated pressures of reactive gas

    Science.gov (United States)

    Gnedovets, A. G.; Fominski, V. Y.; Nevolin, V. N.; Romanov, R. I.; Fominski, D. V.; Soloviev, A. A.

    2017-12-01

    The films of tungsten oxides were prepared by pulsed laser ablation of W target in a reactive gas atmosphere (air of laboratory humidity). Optical analysis and ion signal measurements for the laser plume allowed to recognise a threshold gas pressure that suppresses the deposition of non-scattered atomic flux from the plume. When the pressure exceeds about 40 Pa, the films grow due to the deposition of species that could be formed in collisions of W atoms with reactive molecules (e.g., O2). Kinetic Monte Carlo method was used for modelling film growth. Comparison of the model structures with the experimentally prepared films has shown that the growth mechanism of ballistic deposition at a pressure of 40 Pa could be changed on the diffusion limited aggregation at a pressure of ~100 Pa. Thus, a cauliflower structure of the film transformed to a web-like structure. For good correlation of experimental and model structures of WO x , a dimension of structural elements in the model should coincide with W-O cluster size.

  13. Predicting fluorescence quantum yield for anisole at elevated temperatures and pressures

    Science.gov (United States)

    Wang, Q.; Tran, K. H.; Morin, C.; Bonnety, J.; Legros, G.; Guibert, P.

    2017-07-01

    Aromatic molecules are promising candidates for using as a fluorescent tracer for gas-phase scalar parameter diagnostics in a drastic environment like engines. Along with anisole turning out an excellent temperature tracer by Planar Laser-Induced Fluorescence (PLIF) diagnostics in Rapid Compression Machine (RCM), its fluorescence signal evolution versus pressure and temperature variation in a high-pressure and high-temperature cell have been reported in our recent paper on Applied Phys. B by Tran et al. Parallel to this experimental study, a photophysical model to determine anisole Fluorescence Quantum Yield (FQY) is delivered in this paper. The key to development of the model is the identification of pressure, temperature, and ambient gases, where the FQY is dominated by certain processes of the model (quenching effect, vibrational relaxation, etc.). In addition to optimization of the vibrational relaxation energy cascade coefficient and the collision probability with oxygen, the non-radiative pathways are mainly discussed. The common non-radiative rate (intersystem crossing and internal conversion) is simulated in parametric form as a function of excess vibrational energy, derived from the data acquired at different pressures and temperatures from the literature. A new non-radiative rate, namely, the equivalent Intramolecular Vibrational Redistribution or Randomization (IVR) rate, is proposed to characterize anisole deactivated processes. The new model exhibits satisfactory results which are validated against experimental measurements of fluorescence signal induced at a wavelength of 266 nm in a cell with different bath gases (N2, CO2, Ar and O2), a pressure range from 0.2 to 4 MPa, and a temperature range from 473 to 873 K.

  14. Low job control is associated with higher diastolic blood pressure in men with mildly elevated blood pressure: the Rosai Karoshi study.

    Science.gov (United States)

    Hattori, Tomomi; Munakata, Masanori

    2015-01-01

    Job strain is a risk factor for hypertension, but it is not fully understood if components of job strain, or job demand or job control per se could be related to blood pressure (BP), and if so, whether the relationship differs between normotension and mildly elevated BP. We examined resting BP, and job stress components in 113 Japanese male hospital clerks (38.1 ± 4.4 yr). Subjects were classified into normotensive (NT) (<130/85 mmHg, n=83) and mildly elevated BP (ME) (≥130/85 mmHg) groups. Diastolic BP (DBP) showed a significant interaction between group and job control level (p=0.013). Subjects with low job control demonstrated higher DBP than those with high job control (89.1 ± 2.1 vs. 82.3 ± 2.3 mmHg, p=0.042) in ME group even after adjustments for covariates while DBP did not differ between low and high job control subjects in NT group. Systolic BP (SBP) did not differ between high and low job control subjects in both groups. Neither SBP nor DBP differed between high and low demand groups in either group. Among job strain components, job control may be independently related to BP in Japanese male workers with mildly elevated BP.

  15. ICP curve morphology and intracranial flow-volume changes

    DEFF Research Database (Denmark)

    Unnerbäck, Mårten; Ottesen, Johnny T.; Reinstrup, Peter

    2018-01-01

    proposed to shape the ICP curve. This study tested the hypothesis that the ICP curve correlates to intracranial volume changes. METHODS: Cine phase contrast magnetic resonance imaging (MRI) examinations were performed in neuro-intensive care patients with simultaneous ICP monitoring. The MRI was set......BACKGROUND: The intracranial pressure (ICP) curve with its different peaks has been extensively studied, but the exact physiological mechanisms behind its morphology are still not fully understood. Both intracranial volume change (ΔICV) and transmission of the arterial blood pressure have been...

  16. Virgin Coconut Oil Prevents Blood Pressure Elevation and Improves Endothelial Functions in Rats Fed with Repeatedly Heated Palm Oil

    Directory of Open Access Journals (Sweden)

    Badlishah Sham Nurul-Iman

    2013-01-01

    Full Text Available This study was performed to explore the effects of virgin coconut oil (VCO in male rats that were fed with repeatedly heated palm oil on blood pressure, plasma nitric oxide level, and vascular reactivity. Thirty-two male Sprague-Dawley rats were divided into four groups: (i control (basal diet, (ii VCO (1.42 mL/kg, oral, (iii five-times-heated palm oil (15% (5HPO, and (iv five-times-heated palm oil (15% and VCO (1.42 mL/kg, oral (5HPO + VCO. Blood pressure was significantly increased in the group that was given the 5HPO diet compared to the control group. Blood pressure in the 5HPO + VCO group was significantly lower than the 5HPO group. Plasma nitric oxide (NO level in the 5HPO group was significantly lower compared to the control group, whereas in the 5HPO + VCO group, the plasma NO level was significantly higher compared to the 5HPO group. Aortic rings from the 5HPO group exhibited attenuated relaxation in response to acetylcholine and sodium nitroprusside as well as increased vasoconstriction to phenylephrine compared to the control group. Aortic rings from the 5HPO + VCO group showed only attenuated vasoconstriction to phenylephrine compared to the 5HPO group. In conclusion, VCO prevents blood pressure elevation and improves endothelial functions in rats fed with repeatedly heated palm oil.

  17. Graves' disease and idiopathic intracranial hypertension

    Directory of Open Access Journals (Sweden)

    Manish Gutch

    2017-01-01

    Full Text Available Idiopathic intracranial hypertension (IIH is a central nervous system disorder characterized by raised intracranial pressure with normal cerebrospinal fluid composition and absence of any structural anomaly on neuroimaging. Among all endocrine disorders associated with the development of IIH, the association of hyperthyroidism and IIH is very rare with few cases reported till date. Thyroid disturbances have a unique association with IIH. Hypo- and hyper-thyroidism have been reported in association with this disorder. We present a rare case of a 25-year-old man with Graves' disease with intractable headache that was later investigated and attributed to development of IIH.

  18. "EFFECTIVENESS OF ABDOMINAL WALL ELEVATOR IN REDUCING INTRA-ABDOMINAL PRESSURE AND CO2 VOLUME DURING LAPAROSCOPIC CHOLECYSTECTOMY"

    Directory of Open Access Journals (Sweden)

    A. Yaghoobi Notash

    2004-06-01

    Full Text Available Since CO2 pneumoperitoneum is the dominant method of laparoscopic exposure due to facility and good view, its physiologic effects are most relevant to the surgeons. CO2 pneumoperitoneum may affects hemodynamics by increased intra-abdominal pressure (IAP and the physiologic effects of absorbed CO2. The adverse effects of both mechanisms relate directly to the duration of the pneumoperitoneum and the elevation of IAP. Gasless laparoscopy involves obtaining exposure for laparoscopy by placing an internal retracting device through a small incision and lifting the anterior abdominal wall. We designed and made a mechanical wall elevator and used it in 24 patients, compared with a control group (52 cases using a conventional laparoscopic cholecystectomy. A prospective trial was undertaken in Sina Hospital, Tehran University of Medical Sciences from 1998 to 2000. The patients were assigned randomly to two groups. There was a significant decrease in IAP and CO2 consumption in the group using mechanical wall elevator as compared to conventional laparoscopic cholecystectomy, (mean IAP of 3.5 mmHg compared to 11.4 mmHg in the control group, mean CO2 volume 17 liters compared to 73 liters in the control group. We recommend this semigasless method in laparoscopy due to safety in performance and significant reduction in IAP through the surgery. This method provides a satisfactory view and easy performance without any increase in time or complications. The hospital stay and costs did not increase.

  19. [Transient elevation of intraocular pressure in primary open-angle glaucoma patients after automated visual field examination in the winter].

    Science.gov (United States)

    Nishino, Kazuaki; Yoshida, Fujiko; Nitta, Akari; Saito, Mieko; Saito, Kazuuchi

    2013-12-01

    To evaluate retrospectively seasonal fluctuations of transient intraocular pressure (IOP) elevation after automated visual field examination in patients with primary open-angle glaucoma (POAG). We reviewed 53 consecutive patients with POAG who visited Kaimeido Ophthalmic and Dental Clinic from January 2011 to March 2013, 21 men and 32 women aged 67.7 +/- 11.2 years. The patients were divided into 4 groups, spring, summer, autumn, and winter according to the month of automated visual field examination and both eyes of each patient were enrolled. IOP was measured immediately after automated visual field examination (vf IOP) and compared with the average IOP from the previous 3 months (pre IOP) and with the average IOP from the following 3 months (post IOP) in each season. IOP elevation rate was defined as (vf IOP- pre IOP)/pre IOP x 100% and calculated for each season (paired t test). Additionally, the correlation between mean deviation (MD) and IOP elevation rate was evaluated (single regression analysis). Exclusion criteria were patients who received cataract surgery during this study or had a history of any previous glaucoma surgery. The automated visual field test was performed with a Humphrey field analyzer and the Central 30-2 FASTPAC threshold program. The average vf IOP was 14.5 +/- 2.5 mmHg, higher than pre IOP 13.8 +/- 2.4 mmHg (p field examination, especially in the winter but not in the summer.

  20. Determining noncondensible gas fractions at elevated temperatures and pressures using wet and dry bulb temperature measurements

    International Nuclear Information System (INIS)

    Griffith, P.; Bowman, J.

    1987-01-01

    The work reported in this note was undertaken to provide a method of determining the noncondensible gas fractions in a steam-gas mixture such as might be found in large reactor safety experiment like LOFT. In essence, the method used involves measuring the wet and dry bulb temperatures and using an algorithm, in place of the psychometric chart, to determine the partial pressure of the noncondensible gas in the mixture. In accomplishing this, the authors did the following: (1) extended the use of wet and dry-bulb temperature readings to determine mixture composition up to a temperature of 589 K and a pressure of 4.13 x 10 6 Pa. (2) developed an algorithm to reduce the data (3) found which materials would survive those temperatures

  1. The lifetime of a long cylindrical shell under external pressure at elevated temperature

    CERN Document Server

    Bargmann, H W

    1972-01-01

    This paper is concerned with creep collapse of a long, thin walled, circular, cylindrical shell subjected to external pressure. The problem has been studied by Hoff et al. (1959), where elasticity has been neglected in the material equations. In the present paper it is pointed out that elasticity must not be neglected in stability problems as it may reduce the lifetime considerably. The improved equation for the lifetime of the shell is presented. Moreover, a procedure is indicated to derive the necessary creep parameters easily from usually available creep data. Numerical values of the lifetime of thin-walled, circular, cylindrical shells under external atmospheric pressure are presented for a wide range of shells of different geometrical characteristics for a number of high-temperature alloys and the temperature range up to 1000 degrees C. Experimental results are reported which are in good agreement with the theoretical prediction. (11 refs).

  2. Vapor-liquid Phase Equilibria for CO2+Tertpentanol Binary System at Elevated Pressures

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO Jian-cheng; YANG Hao; CHEN Kai-xun

    2011-01-01

    Vapor-liquid phase equilibrium data of tertpentanol in carbon dioxide were measured at temperatures of 313.4,323.4,333.5 and 343.5 K and in the pressure range of 4.56-11.44 MPa.The phase equilibium apparatus used in the work was a variable-volume high-pressure cell.The experimental data were reasonably correlated with Peng-Robinson equation of state(PR-EOS) together with van der Waals-2 two-parameter mixing rules.Henry's Law constants and partial molar volumes of CO2 at infinite dilution were estimated with Krichevsky-Kasarnovsky equation,and Henry's Law constants increase with increasing temperature,however,partial molar volumes of CO2 at infinite dilution are negative whose magnitudes decrease with temperature.Partial molar volumes of CO2 and tertpentanol in liquid phase at equilibrium were calculated.

  3. Non-Invasive Electromagnetic Skin Patch Sensor to Measure Intracranial Fluid–Volume Shifts

    Directory of Open Access Journals (Sweden)

    Jacob Griffith

    2018-03-01

    Full Text Available Elevated intracranial fluid volume can drive intracranial pressure increases, which can potentially result in numerous neurological complications or death. This study’s focus was to develop a passive skin patch sensor for the head that would non-invasively measure cranial fluid volume shifts. The sensor consists of a single baseline component configured into a rectangular planar spiral with a self-resonant frequency response when impinged upon by external radio frequency sweeps. Fluid volume changes (10 mL increments were detected through cranial bone using the sensor on a dry human skull model. Preliminary human tests utilized two sensors to determine feasibility of detecting fluid volume shifts in the complex environment of the human body. The correlation between fluid volume changes and shifts in the first resonance frequency using the dry human skull was classified as a second order polynomial with R2 = 0.97. During preliminary and secondary human tests, a ≈24 MHz and an average of ≈45.07 MHz shifts in the principal resonant frequency were measured respectively, corresponding to the induced cephalad bio-fluid shifts. This electromagnetic resonant sensor may provide a non-invasive method to monitor shifts in fluid volume and assist with medical scenarios including stroke, cerebral hemorrhage, concussion, or monitoring intracranial pressure.

  4. A Poroelasticity Theory Approach to Study the Mechanisms Leading to Elevated Interstitial Fluid Pressure in Solid Tumours.

    Science.gov (United States)

    Burazin, Andrijana; Drapaca, Corina S; Tenti, Giuseppe; Sivaloganathan, Siv

    2018-05-01

    Although the mechanisms responsible for elevated interstitial fluid pressure (IFP) in tumours remain obscure, it seems clear that high IFP represents a barrier to drug delivery (since the resulting adverse pressure gradient implies a reduction in the driving force for transvascular exchange of both fluid and macromolecules). R. Jain and co-workers studied this problem, and although the conclusions drawn from their idealized mathematical models offered useful insights into the causes of elevated IFP, they by no means gave a definitive explanation for this phenomenon. In this paper, we use poroelasticity theory to also develop a macroscopic mathematical model to describe the time evolution of a solid tumour, but focus our attention on the mechanisms responsible for the rise of the IFP, from that for a healthy interstitium to that measured in malignant tumours. In particular, we discuss a number of possible time scales suggested by our mathematical model and propose a tumour-dependent time scale that leads to results in agreement with experimental observations. We apply our mathematical model to simulate the effect of "vascular normalization" (as proposed by Jain in Nat Med 7:987-989, 2001) on the IFP profile and discuss and contrast our conclusions with those of previous work in the literature.

  5. An Ignition Torch Based on Photoignition of Carbon Nanotubes at Elevated Pressure (Briefing Charts)

    Science.gov (United States)

    2016-01-04

    Applications The schematic image of high pressure ignition torch with a remotely operated Xe-flash lamp PITCH provides certain advantages over...combustible fuel mixture • The low voltage (< 350 v) discharge in PITCH produces no electromagnetic interference and its operation is not affected by...EMI or electrostatic discharge • Use of multiple PITCH igniters greatly enhanced the chance of ignition of turbines • The connecting tube delivers

  6. Silicon Monoxide at 1 atm and Elevated Pressures: Crystalline or Amorphous?

    KAUST Repository

    AlKaabi, Khalid

    2014-03-05

    The absence of a crystalline SiO phase under ordinary conditions is an anomaly in the sequence of group 14 monoxides. We explore theoretically ordered ground-state and amorphous structures for SiO at P = 1 atm, and crystalline phases also at pressures up to 200 GPa. Several competitive ground-state P = 1 atm structures are found, perforce with Si-Si bonds, and possessing Si-O-Si bridges similar to those in silica (SiO2) polymorphs. The most stable of these static structures is enthalpically just a little more stable than a calculated random bond model of amorphous SiO. In that model we find no segregation into regions of amorphous Si and amorphous SiO2. The P = 1 atm structures are all semiconducting. As the pressure is increased, intriguing new crystalline structures evolve, incorporating Si triangular nets or strips and stishovite-like regions. A heat of formation of crystalline SiO is computed; it is found to be the most negative of all the group 14 monoxides. Yet, given the stability of SiO2, the disproportionation 2SiO (s) → Si(s)+SiO2(s) is exothermic, falling right into the series of group 14 monoxides, and ranging from a highly negative ΔH of disproportionation for CO to highly positive for PbO. There is no major change in the heat of disproportionation with pressure, i.e., no range of stability of SiO with respect to SiO2. The high-pressure SiO phases are metallic. © 2014 American Chemical Society.

  7. NASA's Spaceflight Visual Impairment and Intracranial Hypertension Research Plan: An accelerated Research Collaboration

    Science.gov (United States)

    Otto, Christian; Fogarty, J.; Grounds, D.; Davis, J.

    2010-01-01

    To date six long duration astronauts have experienced in flight visual changes and post flight signs of optic disc edema, globe flattening, choroidal folds, hyperoptic shifts and or raised intracranial pressure. In some cases the changes were transient while in others they are persistent with varying degrees of visual impairment. Given that all astronauts exposed to microgravity experience a cephalad fluid shift, and that both symptomatic and asymptomatic patients have exhibited optic nerve sheath edema on MRI, there is a high probability that all astronauts develop in-flight idiopathic intracranial hypertension to some degree. Those who are susceptible, have an increased likelihood of developing treatment resistant papilledema resulting in visual impairment and possible long-term vision loss. Such an acquired disability would have a profound mission impact and would be detrimental to the long term health of the astronaut. The visual impairment and increased intracranial pressure phenomenon appears to have multiple contributing factors. Consequently, the working "physiological fault bush" with elevated intracranial pressure at its center, is divided into ocular effects, and CNS and other effects. Some of these variables have been documented and or measured through operational data gathering, while others are unknown, undocumented and or hypothetical. Both the complexity of the problem and the urgency to find a solution require that a unique, non-traditional research model be employed such as the Accelerated Research Collaboration(TM) (ARC) model that has been pioneered by the Myelin Repair Foundation. In the ARC model a single entity facilitates and manages all aspects of the basic, translational, and clinical research, providing expert oversight for both scientific and managerial efforts. The result is a comprehensive research plan executed by a multidisciplinary team and the elimination of stove-piped research. The ARC model emphasizes efficient and effective

  8. Right ventricular pressure elevated in one-kidney, one clip Goldblatt hypertensive rats.

    Science.gov (United States)

    Ketabchi, Farzaneh; Bajoovand, Shirin; Adlband, Mojtaba; Naseh, Maryam; Nekooeian, Ali A; Mashghoolozekr, Elaheh

    2017-01-01

    Both renal and respiratory diseases are common with high mortality rate around the world. This study was the first to compare effects of two kidneys, one clip (2K1C) and one-kidney, one clip (1K1C) Goldblatt hypertension on right ventricular pressure during normal condition and mechanical ventilation with hypoxia gas. Male Sprague-Dawley rats were subjected to control, 2K1C, or 1K1C groups. Twenty-eight days after the first surgery, animals were anesthetized, and femoral artery and vein, and right ventricle cannulated. Systemic arterial pressure and right ventricular systolic pressures (RVSP) were recorded during ventilation the animals with normoxic or hypoxic gas. RVSP in the 1K1C group was significantly more than the control and 2K1C groups during baseline conditions and ventilation the animals with hypoxic gas. Administration of antioxidant Trolox increased RVSP in the 1K1C and control groups compared with their baselines. Furthermore, there was no alteration in RVSP during hypoxia in the presence of Trolox. This study indicated that RVSP only increased after 28 days induction of 1K1C but not 2K1C model. In addition, it seems that the response to hypoxic gas and antioxidants in 1K1C is more than 2K1C. These data also suggest that effects of 1K1C may partially be related to reactive oxygen species (ROS) pathways.

  9. Intracranial Hemorrhage Following a 3-week Headache

    Directory of Open Access Journals (Sweden)

    John Jiao

    2017-01-01

    Full Text Available History of present illness: A 35-year-old female presented to the ED with a Glasgow Coma Scale (GCS of 11. Per her boyfriend, the patient was having headaches for the past 3 weeks. She was initially taken to an outside hospital where her GCS was reported as 13. A non-contrast head computed tomography (CT revealed a large lobar intraparenchymal hemorrhage within the left frontal parietal lobe with midline shift. Upon examination, vitals were notable for blood pressure of 209/88mmHg, and her left pupil was fixed and dilated. The patient had extension of her right arm to noxious stimuli, paralysis of her right leg, and purposeful movement of the left arm and left leg. The patient was started on a nicardipine drip in the ED and subsequently taken to the operating room for a decompressive craniectomy. Significant findings: The patient’s head CT showed a significant area of hyperdensity consistent with an intracranial hemorrhage located within the left frontal parietal lobe (red arrow. Additionally, there is rightward midline shift up to 1.1cm (green arrow and entrapment of the right lateral ventricle (blue arrow. Discussion: Intraparenchymal hemorrhage (IPH is associated with high morbidity and mortality. Although the mortality for subarachnoid hemorrhage (SAH has declined steadily over the past several decades, the mortality for IPH mortality has not significantly.1 One of the most serious considerations when treating a patient with IPH is the management of intracranial pressure (ICP.2 Once an IPH is identified, immediate steps should be taken to bring ICP within acceptable levels including elevating the head of the bed to 30 degrees, sedation, and controlling hypertension with medications.2-3 Even with early and aggressive care, the prognosis for IPH remains poor; the 30-day mortality rate for IPH is estimated to be less than 50%, and a 2010 systematic review estimated only 12-39% of IPH patients achieve independent function.4-5 Predictors of

  10. Fluid and rock interactions in silicate and aluminosilicate systems at elevated pressure and temperature

    Science.gov (United States)

    Davis, Mary Kathleen

    Understanding fluid chemistry in the subduction zone environment is key to unraveling the details of element transport from the slab to the surface. Solubilities of cations, such as silicon, in water strongly affect both the physical and chemical properties of supercritical metamorphic fluids. Modeling the thermodynamics of fluid-rock interactions requires therefore a profound understanding of cation dissolution and aqueous speciation. In situ Raman experiments of the silica-water, alumina-water, and alumina water systems were performed in an externally heated Bassett-type diamond-anvil cell at the Department of Geological Sciences, University of Michigan. Natural quartz samples and synthetic ruby samples were used in the experiments. Samples were loaded in the sample chamber with a water pressure medium. All experiments used rhenium gaskets of uniform thickness with a 500 mum drill hole for the sample chamber. Temperature was measured using K-type thermocouples encompassing both the upper and lower diamond anvils. Pressures are obtained on the basis of the Raman shift of the 464 cm-1 quartz mode where possible or the Raman shift of the tips of the diamond anvils according to a method developed in this work. This work characterizes the state of stress in the diamond anvil cell, which is used as the basis for the pressure calibration using only the diamond anvils. Raman measurements of silicate fluid confirm the presence of H4 SiO4 and H6Si2O7 in solution and expand the pressure range for in-situ structural observations in the silica-water system. Additionally, we identify the presence of another silica species present at mantle conditions, which occurs at long time scales in the diamond cell. This study provides the first in situ data in the alumina-water and alumina-silica-water systems at pressures and temperatures relevant to the slab environment. Al(OH) 3 appears to be the dominant form of alumina present under these conditions and in the alumina

  11. Structural evolution of a uranyl peroxide nano-cage fullerene: U60, at elevated pressures

    Science.gov (United States)

    Turner, K. M.; Lin, Y.; Zhang, F.; McGrail, B.; Burns, P. C.; Mao, W. L.; Ewing, R. C.

    2015-12-01

    U60 is a uranyl peroxide nano-cage that adopts a highly symmetric fullerene topology; it is topologically identical to C60. Several studies on the aqueous-phase of U60 clusters, [UO2(O2)(OH)]6060-, have shown its persistence in complex solutions and over lengthy time scales. Peroxide enhances corrosion of nuclear fuel in a reactor accident-uranyl peroxides often form near contaminated sites. U60 (Fm-3) crystallizes with approximate formula: Li68K12(OH)20[UO2(O2)(OH)]60(H2O)310. Here, we have used the diamond anvil cell (DAC) to examine U60 to understand the stability of this cluster at high pressures. We used a symmetric DAC with 300 μm culet diamonds and two different pressure-transmitting media: a mixture of methanol+ethanol and silicone oil. Using a combination of in situ Raman spectroscopy and synchrotron XRD, and electrospray ionization mass spectroscopy (ESI-MS) ex situ, we have determined the pressure-induced evolution of U60. Crystalline U60 undergoes an irreversible phase transition to a tetragonal structure at 4.1 GPa, and irreversibly amorphizes at 13 GPa. The amorphous phase likely consists of clusters of U60. Above 15 GPa, the U60 cluster is irreversibly destroyed. ESI-MS shows that this phase consists of species that likely have between 10-20 uranium atoms. Raman spectroscopy complements the diffraction measurements. U60 shows two dominant vibrational modes: a symmetric stretch of the uranyl U-O triple bond (810 cm-1), and a symmetric stretch of the U-O2-U peroxide bond (820 cm-1). As pressure is increased, these modes shift to higher wavenumbers, and overlap at 4 GPa. At 15 GPa, their intensity decreases below detection. These experiments reveal several novel behaviors including a new phase of U60. Notably, the amorphization of U60 occurs before the collapse of its cluster topology. This is different from the behavior of solvated C60 at high pressure, which maintains a hcp structure up to 30 GPa, while the clusters disorder. These results suggest

  12. Spectral domain optical coherence tomography cross-sectional image of optic nerve head during intraocular pressure elevation

    Directory of Open Access Journals (Sweden)

    Ji Young Lee

    2014-12-01

    Full Text Available AIM: To analyze changes of the optic nerve head (ONH and peripapillary region during intraocular pressure (IOP elevation in patients using spectral domain optical coherence tomography (SD-OCT.METHODS: Both an optic disc 200×200 cube scan and a high-definition 5-line raster scan were obtained from open angle glaucoma patients presented with monocular elevation of IOP (≥30 mm Hg using SD-OCT. Additional baseline characteristics included age, gender, diagnosis, best-corrected visual acuity, refractive error, findings of slit lamp biomicroscopy, findings of dilated stereoscopic examination of the ONH and fundus, IOP, pachymetry findings, and the results of visual field.RESULTS: The 24 patients were selected and divided into two groups:group 1 patients had no history of IOP elevation or glaucoma (n=14, and group 2 patients did have history of IOP elevation or glaucoma (n=10. In each patient, the study eye with elevated IOP was classified into group H (high, and the fellow eye was classified into group L (low. The mean deviation (MD differed significantly between groups H and L when all eyes were considered (P=0.047 and in group 2 (P=0.042, not in group 1 (P=0.893. Retinal nerve fiber layer (RNFL average thickness (P=0.050, rim area (P=0.015, vertical cup/disc ratio (P=0.011, cup volume (P=0.028, inferior quadrant RNFL thickness (P=0.017, and clock-hour (1, 5, and 6 RNFL thicknesses (P=0.050, 0.012, and 0.018, respectively, cup depth (P=0.008, central prelaminar layer thickness (P=0.023, mid-inferior prelaminar layer thickness (P=0.023, and nasal retinal slope (P=0.034 were significantly different between the eyes with groups H and L.CONCLUSION:RNFL average thickness, rim area, vertical cup/disc ratio, cup volume, inferior quadrant RNFL thickness, and clock-hour (1, 5, and 6 RNFL thicknesses significantly changed during acute IOP elevation.

  13. Measurements and correlations of turbulent burning velocities over wide ranges of fuels and elevated pressures

    KAUST Repository

    Bradley, Derek; Lawes, Malcolm; Liu, Kexin; Mansour, Morkous S.

    2013-01-01

    The implosion technique has been used to extend measurements of turbulent burning velocities over greater ranges of fuels and pressures. Measurements have been made up to 3.5 MPa and at strain rate Markstein numbers as low as 23. The implosion technique, with spark ignition at two opposite wall positions within a fan-stirred spherical bomb is capable of measuring turbulent burning velocities, at higher pressures than is possible with central ignition. Pressure records and schlieren high speed photography define the rate of burning and the smoothed area of the flame front. The first aim of the study was to extend the previous measurements with ethanol and propane-air, with further measurements over wider ranges of fuels and equivalence ratios with mixtures of hydrogen, methane, 10% hydrogen-90% methane, toluene, and i-octane, with air. The second aim was to study further the low turbulence regime in which turbulent burning co-exists with laminar flame instabilities. Correlations are presented of turbulent burning velocity normalised by the effective rms turbulent velocity acting on the flame front, ut=u0k , with the Karlovitz stretch factor, K, for different strain rate Markstein numbers, a decrease in which increases ut=u0k . Experimental correlations are presented for the present measurements, combined with previous ones. Different burning regimes are also identified, extending from that of mixed turbulence/laminar instability at low values of K to that at high values of K, in which ut=u0k is gradually reduced due to increasing localised flame extinctions. © 2012 The Combustion Institute.

  14. Permeability of shale at elevated temperature and pressure: Test methodology and preliminary results

    International Nuclear Information System (INIS)

    Myer, L.R.; Christian, T.L.

    1987-05-01

    A method of measuring the hydraulic conductivity of low permeability shale as a function of pressure and temperature has been developed and successfully demonstrated. Measurements have been performed on samples of Green River Formation up to a temperature of 140 0 C. For flow parallel to bedding hydraulic conductivities increased nonlinearly from 1.75 x 10 -16 m/s (1.6 x 10 -23 m 2 ) at 25 0 C, to 5.6 x 10 -15 m/s (1.4 x 10 -22 m 2 ) at 140 0 C. This increase in permeability with temperature may reflect an increase in microcrack porosity resulting from the heating

  15. Short-Term Changes in Weather and Space Weather Conditions and Emergency Ambulance Calls for Elevated Arterial Blood Pressure

    Directory of Open Access Journals (Sweden)

    Jone Vencloviene

    2018-03-01

    Full Text Available Circadian rhythm influences the physiology of the cardiovascular system, inducing diurnal variation of blood pressure. We investigated the association between daily emergency ambulance calls (EACs for elevated arterial blood pressure during the time intervals of 8:00–13:59, 14:00–21:59, and 22:00–7:59 and weekly fluctuations of air temperature (T, barometric pressure, relative humidity, wind speed, geomagnetic activity (GMA, and high-speed solar wind (HSSW. We used the Poisson regression to explore the association between the risk of EACs and weather variables, adjusting for seasonality and exposure to CO, PM10, and ozone. An increase of 10 °C when T > 1 °C on the day of the call was associated with a decrease in the risk of EACs during the time periods of 14:00–21:59 (RR (rate ratio = 0.78; p < 0.001 and 22:00–7:59 (RR = 0.88; p = 0.35. During the time period of 8:00–13:59, the risk of EACs was positively associated with T above 1 °C with a lag of 5–7 days (RR = 1.18; p = 0.03. An elevated risk was associated during 8:00–13:59 with active-stormy GMA (RR = 1.22; p = 0.003; during 14:00–21:59 with very low GMA (RR = 1.07; p = 0.008 and HSSW (RR = 1.17; p = 0.014; and during 22:00–7:59 with HSSW occurring after active-stormy days (RR = 1.32; p = 0.019. The associations of environmental variables with the exacerbation of essential hypertension may be analyzed depending on the time of the event.

  16. Thermal conductivity and diffusivity of Permian Basin bedded salt at elevated pressure and temperature

    International Nuclear Information System (INIS)

    Durham, W.B.; Boro, C.O.; Beiriger, J.M.; Montan, D.N.

    1983-10-01

    Measurements of thermal conductivity and diffusivity were made on five core samples of bedded rock salt from the Permian Basin in Texas to determine its suitability as an underground nuclear waste repository. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to 31.0 MPa and temperatures from room temperature to 473 K. Conductivity showed no dependence on confining pressure but evidenced a monotonic, negative temperature dependence. Four of the five samples showed conductivities clustered in a range of 5.6 +- 0.5 W/m.K at room temperature, falling to 3.6 +- 0.3 W/m.K at 473 K. These values are approximately 20% below those for pure halite, reflecting perhaps the 5 to 20%-nonhalite component of the samples. Diffusivity also showed a monotonic, negative temperature dependence, with four of the five samples clustered in a range of 2.7 +- 0.4 x 10 -6 m 2 /s at room temperature, and 1.5 +- 0.3 x 10 -6 m 2 /s at 473 K, all roughly 33% below the values for pure halite. One sample showed an unusually high conductivity (it also had the highest diffusivity), about 20% higher than the others; and one sample showed an unusually low diffusivity (it also had the lowest conductivity), roughly a factor of 2 lower than the others. 27 references, 8 figures, 4 tables

  17. Tafluprost once daily for treatment of elevated intraocular pressure in patients with open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Liu Y

    2012-12-01

    Full Text Available Yang Liu, Weiming MaoDepartment of Cell Biology and Anatomy, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TXAbstract: Glaucoma is a leading cause of visual loss worldwide. Current antiglaucoma therapy focuses on lowering intraocular pressure to a safe level. In recent years, prostaglandin analogs have become the first-line agents for treating open angle glaucoma. Tafluprost, which was first reported in 2003, is a novel prostaglandin analog, and has been shown to be a potent ocular hypotensive agent in a number of preclinical and clinical studies. Also, its unique preservative-free formulation helps to decrease preservative-associated ocular disorders and improve patient compliance. In this review, studies from 2003 to 2012 focusing on the structure, metabolism, efficacy, and safety of tafluprost are summarized. These studies suggested that application of tafluprost once daily is a safe and effective treatment for patients with open angle glaucoma.Keywords: tafluprost, prostaglandin analog, glaucoma, intraocular pressure, preservative-free formulation

  18. Creep strength of hastelloy X TIG-welded cylinder under internal pressure at elevated temperature

    International Nuclear Information System (INIS)

    Udoguchi, Teruyoshi; Indo, Hirosato; Isomura, Kazuyuki; Kobatake, Kiyokazu; Nakanishi, Tsuneo.

    1981-01-01

    Creep tests on circumferentially TIG-welded Hastelloy x cylinders were carried out under internal pressure for the investigation of structural behavior of welded components in high temperature environment. The creep rupture strength of TIG-welded cylinders was much lower than that of non-welded cylinders, while such reduction was not found in uniaxial creep tests on TIG-welded bars. It was deduced that the reduction was due to the low ductility (ranging from 1 to 5%) of the weld metal to which enhanced creep was induced by the adjacent base metal whose creep strain rate was much higher than that of the weld metal. Therefore, uniaxial creep tests on bar specimens is not sufficient for proper assessment of the creep rupture strength of welded components. Both creep strain rate and creep ductility should be concerned for the assessment. Creep tests by using components such as cylinder under internal pressure are recommendable for the confirmation of creep strength of welded structures and components. (author)

  19. 164Ile allele in the beta2-Adrenergic receptor gene is associated with risk of elevated blood pressure in women. The Copenhagen City Heart Study

    DEFF Research Database (Denmark)

    Sethi, AA; Tybjærg-Hansen, A; Jensen, Gorm Boje

    2005-01-01

    Since beta2-adrenergic receptors are important regulators of blood pressure, genetic variation in this receptor could explain risk of elevated blood pressure in selected individuals. We tested the hypothesis that Gly16Arg, Gln27Glu, and Thr164Ile in the beta2-adrenergic receptor gene associated w...

  20. Interfacial area transport in two-phase flows in a scaled 8X8 rod bundle geometry at elevated pressures

    International Nuclear Information System (INIS)

    Yang, X; Schlegel, J.P.; Paranjape, S.; Liu, Y.; Chen, S.W.; Hibiki, T.; Ishii, M.

    2011-01-01

    To improve the prediction accuracy and robustness of the next-generation thermal-hydraulics system analysis code, analytical and experimental research has been undertaken to develop the Interfacial Area Transport Equation (IATE) in a scaled 8x8 rod bundle geometry at elevated pressure conditions. The experiments performed include local measurements of void fraction, interfacial area concentration, and gas velocity at several axial locations using the innovative four-sensor conductivity probe. The test conditions cover a wide range of flow regimes from bubbly, cap-bubbly, cap-turbulent to churn-turbulent at 100 kPa and 300 kPa pressure conditions and the obtained data indicates some spacer effects on the flow parameters. The bubble groups are classified into two groups (Group-1: spherical and distorted bubbles, Group-2: cap and churn turbulent bubbles) based on the bubble transport characteristics. The area-averaged interfacial area transport data have been compared to the prediction by the one-dimensional two-group IATE with mechanistically modeled IAC source and sink terms. The one-group IATE is able to predict the bubbly-flow interfacial area within ±15% error under two pressure conditions. The two-group IATE performance is also very promising in the cap-bubbly flow and churn-turbulent flow regimes, with average error of about ±20%. (author)

  1. Pigment dispersion and chronic intraocular pressure elevation after sulcus placement of 3-piece acrylic intraocular lens.

    Science.gov (United States)

    Almond, M Camille; Wu, Michael C; Chen, Philip P

    2009-12-01

    A 55-year-old man had phacoemulsification and implantation of a 3-piece acrylic intraocular lens (IOL) (AcrySof MA60AC) in the right eye. One month postoperatively, the intraocular pressure (IOP) was 48 mm Hg and peripheral transillumination defects were noted in the iris circumferentially, with the IOL optic edge visible as a silhouette. Gonioscopy showed dense pigmentation of the trabecular meshwork in the right eye, but in the left eye, only mild trabecular meshwork pigment was seen, along with a concave peripheral iris insertion. At 21 months, the right eye required 3 medications for IOP control. While pigment dispersion has been widely reported after placement of 1-piece acrylic IOLs in the ciliary sulcus, we conclude that in susceptible individuals with a concave peripheral iris insertion, pigment dispersion can occur with sulcus placement of a 3-piece acrylic model despite its thinner optic and angulated haptics.

  2. Investigation of LPP combustors under elevated pressure conditions; Untersuchungen zu LPP-Flugtriebwerksbrennkammern unter erhoehtem Druck

    Energy Technology Data Exchange (ETDEWEB)

    Fink, R.

    2001-05-01

    The development of new combustor concepts for aero engines to meet future emissions regulations in based on a detailed knowledge of the combustion process and the velocity field. In the presented thesis, non intrusive measurements were performed in a model combustion chamber under almost realistic pressure and temperature conditions. The species OH, NO, unburned hydrocarbons and fuel droplets were detected in 2 dimensions with the Laser Induced Fluorescence (LIF). The velocity field was measured with the Particle Image Velocimetry technique (PIV). [German] Die Weiterentwicklung neuer Brennkammerkonzepte zur Erfuellung zukuenftiger Schadstoffemissionsrichtlinien erfordert genaue Kenntnisse der ablaufenden Verbrennungs- und Stroemungsvorgaenge in der Brennkammer. Bei den in der Arbeit vorgestellten Untersuchungen wurden in einer LPP-Modellbrennkammer unter annaehernd realistischen Eintrittsbedingungen die Spezies OH, NO, unverbrannte Kohlenwasserstoffe sowie noch fluessiger Brennstoff zweidimensional anhand der Laserinduzierten Fluoreszenz (LIF) nachgewiesen. Das Stroemungsfeld wurde mit Hilfe der Particle Image Velocimetry (PIV) gemessen.

  3. Laminar burning velocities at elevated pressures for gasoline and gasoline surrogates associated with RON

    KAUST Repository

    Mannaa, Ossama

    2015-06-01

    The development and validation of a new gasoline surrogate using laminar flame speed as a target parameter is presented. Laminar burning velocities were measured using a constant-volume spherical vessel with ignition at the center of the vessel. Tested fuels included iso-octane, n-heptane, toluene, various mixtures of primary reference fuels (PRFs) and toluene reference fuels (TRFs) and three gasoline fuels of 70, 85 and 95 RON (FACE J, C and F) at the initial temperature of 358K and pressures up to 0.6MPa in the equivalence ratio ranging from 0.8 to 1.6. Normalized laminar burning velocity data were mapped into a tri-component mixture space at different experimental conditions to allocate different gasoline surrogates for different gasoline fuels, having RON of 70, 85 and 95. The surrogates of TRF-70-4 (17.94% iso-C8H18 +42.06% n-C7H16 +40% C7H8), TRF-85-1 (77.4% iso-C8H18 +17.6% n-C7H16 +5% C7H8), and TRF-95-1 (88.47% iso-C8H18 +6.53% n-C7H16 +5% C7H8) of RON 70, 85 and 95, respectively, are shown to successfully emulate the burning rate characteristics of the gasoline fuels associated with these RONs under the various experimental conditions investigated. An empirical correlation was derived to obtain laminar burning velocities at pressures that are experimentally unattainable as high as 3.0MPa. Laminar burning velocities were comparable to the simulated values for lean and stoichiometric flames but they were relatively higher than the simulated values for rich flames. A flame instability assessment was conducted by determining Markstein length, critical Pecklet number, and critical Karlovitz number at the onset of flame instability.

  4. Measurement procedure for the determination of thermal exchange coefficient for subsea pipelines at elevated pressure levels

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Luis Fernando A.; Farias, Paula S.C.; Martins, Fabio J.W.A.; Rabello, Pedro C.; Barros Junior, Julio M. [Pontificia Universidade Catolica (PUC-Rio), RJ (Brazil). Dept. de Engenharia Mecanica; Lopes Junior, Fernando M.; Silva Junior, Jose Fernando; Castro, Adriana M.; Santos, Augusto A.; Pessanha, Maikon C.R. [Technip, Rio de Janeiro, RJ (Brazil)

    2009-12-19

    The present paper describes a methodology successfully employed to determine the Thermal Exchange Coefficient - TEC - for insulated sub sea flexible lines up to a pressure level of 200 bar. In this methodology, controlled internal electrical heating was employed, together with temperature sensors installed at the inner and outer surfaces of the line. The instrumented line sample was placed in a hyperbaric chamber filled with water. Two methods were employed in parallel to determine the line TEC value. In the first method, the TEC value was determined by direct measurement of the radial heat flux by the use of heat flux sensors. The readings of these sensors, together with the inner-to-outer surface temperature difference and geometric parameters, yielded the desired TEC value. In the second method, the radial heat flux was obtained as the difference between the total energy generated by the electrical heater installed in the interior of the sample and the heat losses through the end connectors, evaluated by the readings of temperature sensors installed in covers that surrounded the end connectors. The knowledge of the cover geometry, thermal properties and the temperature readings allowed for an accurate estimate of the heat lost through the covers. Both measuring methods were backed by a detailed uncertainty analysis. A calibration procedure of the second method was performed from zero to 100 bar, the pressure range where the calibration of the heat flux sensor is valid. Beyond 100 bar and up to 200 bar, the TEC values were obtained by the second method, corrected by the calibration procedure extrapolated from the 0-100 bar range. The TEC values obtained were valid under an uncertainty level of {+-} 5%. (author)

  5. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

  6. Evidence for negative effects of elevated intra-abdominal pressure on pulmonary mechanics and oxidative stress.

    Science.gov (United States)

    Davarcı, I; Karcıoğlu, M; Tuzcu, K; İnanoğlu, K; Yetim, T D; Motor, S; Ulutaş, K T; Yüksel, R

    2015-01-01

    To compare the effects of pneumoperitoneum on lung mechanics, end-tidal CO2 (ETCO2), arterial blood gases (ABG), and oxidative stress markers in blood and bronchoalveolar lavage fluid (BALF) during laparoscopic cholecystectomy (LC) by using lung-protective ventilation strategy. Forty-six patients undergoing LC and abdominal wall hernia (AWH) surgery were assigned into 2 groups. Measurements and blood samples were obtained before, during pneumoperitoneum, and at the end of surgery. BALF samples were obtained after anesthesia induction and at the end of surgery. Peak inspiratory pressure, ETCO2, and pCO2 values at the 30th minute were significantly increased, while there was a significant decrease in dynamic lung compliance, pH, and pO2 values in LC group. In BALF samples, total oxidant status (TOS), arylesterase, paraoxonase, and malondialdehyde levels were significantly increased; the glutathione peroxidase levels were significantly decreased in LC group. The serum levels of TOS and paraoxonase were significantly higher at the end of surgery in LC group. In addition, arylesterase level in the 30th minute was increased compared to baseline. Serum paraoxonase level at the end of surgery was significantly increased when compared to AWH group. Our study showed negative effects of pneumoperitoneum in both lung and systemic levels despite lung-protective ventilation strategy.

  7. Evidence for Negative Effects of Elevated Intra-Abdominal Pressure on Pulmonary Mechanics and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    I. Davarcı

    2015-01-01

    Full Text Available Objective. To compare the effects of pneumoperitoneum on lung mechanics, end-tidal CO2 (ETCO2, arterial blood gases (ABG, and oxidative stress markers in blood and bronchoalveolar lavage fluid (BALF during laparoscopic cholecystectomy (LC by using lung-protective ventilation strategy. Materials and Methods. Forty-six patients undergoing LC and abdominal wall hernia (AWH surgery were assigned into 2 groups. Measurements and blood samples were obtained before, during pneumoperitoneum, and at the end of surgery. BALF samples were obtained after anesthesia induction and at the end of surgery. Results. Peak inspiratory pressure, ETCO2, and pCO2 values at the 30th minute were significantly increased, while there was a significant decrease in dynamic lung compliance, pH, and pO2 values in LC group. In BALF samples, total oxidant status (TOS, arylesterase, paraoxonase, and malondialdehyde levels were significantly increased; the glutathione peroxidase levels were significantly decreased in LC group. The serum levels of TOS and paraoxonase were significantly higher at the end of surgery in LC group. In addition, arylesterase level in the 30th minute was increased compared to baseline. Serum paraoxonase level at the end of surgery was significantly increased when compared to AWH group. Conclusions. Our study showed negative effects of pneumoperitoneum in both lung and systemic levels despite lung-protective ventilation strategy.

  8. Heterogeneously catalyzed deuterium separation processes: Hydrogen-water exchange studies at elevated temperatures and pressures

    International Nuclear Information System (INIS)

    Halliday, J.D.; Rolston, J.H.; Au, J.C.; Den Hartog, J.; Tremblay, R.R.

    1985-01-01

    New processes for the separation of hydrogen isotopes are required to produce heavy water for CANDU nuclear reactors and to extract tritium formed in the moderator during reactor operation. Wetproofed platinum catalysts capable of promoting rapid exchange of isotopes between countercurrent flows of hydrogen and liquid water in packed columns have been developed at CRNL over the past 15 years. These catalysts provide a catalystic surface for the gas phase exchange reaction H/sub 2/O/sub (v)/ + HD/sub (g)/ ↔ HDO/sub (v)/ + H/sub 2(g)/ as well as a large liquid surface for the liquid phase isotope transfer reaction HDO/sub (v)/ + H/sub 2/O/sub (iota)/↔HDO/sub (iota)/+H/sub 2/O/sub (v)/. Any economic stand-alone heavy water separation process, based on bithermal hydrogen-water exchange over wetproofed platinum catalysts, requires rapid overall exchange of isotopes between two phases at two temperatures. Catalysts developed for cold tower operation at 25-60 0 C are now being tested in a laboratory scale stainless steel trickle bed reactor for performance and stability at simulated hot tower conditions, 150 0 C and 2.0 MPa pressure. Catalytically active layers containing platinum supported on carbon or crystalline silica and wetproofed with Teflon have been prepared on ceramic spheres and stainless steel screening and tested in both random and ordered bed columns

  9. Formation and destruction of nitrogen oxides at elevated pressures with mixed fuels; Typenoksidimuodostus ja tuhoaminen paineistetuissa olosuhteissa ja ongelmapolttoaineilla

    Energy Technology Data Exchange (ETDEWEB)

    Aho, M.; Haemaelaeinen, J.; Paakkinen, K.; Rantanen, J. [VTT Energy, Jyvaeskylae (Finland)

    1997-10-01

    Destruction of NO with NH{sub 3} (Thermal DeNO{sub x}) and formation of nitrogen oxides (especially NO{sub 2}) from fuel nitrogen were studied at elevated pressure (up to 15 bar) with a pressurized entrained flow reactor (PEFR) at conditions simulating freeboard area of pressurized fluidized bed boiler. Effect of HCl on the oxidation of CO was studied at atmospheric pressure. These results give information about emission formation during combustion of chlorine-containing wastes. N{sub x}O{sub y} formation from fuel mixtures will be studied with a new fluidized bed reactor (FBR) in 1997. Thermal DeNox-experiments were performed at p= 2-15 bar, T= 700-950 deg C. Concentrations of NO, N{sub 2}O, NO{sub 2} and NH{sub 3} were measured at different residence times (0.2-2s). After the experiments with the bare NH{sub 3}/NO mixture, the effects of two additional gases (N{sub 2}O and CO) were measured. A new reaction tube made of quartz was employed to prevent catalytic destruction of NH{sub 3}. Formation of NO{sub 2} was studied with eleven solid fuels. The first experiments were carried out at 12 bar, O{sub 2}=20-19 %, PO{sub 2}=2.4 bar and the additional ones at p=8 bar, O{sub 2}=4-5 % => PO{sub 2}=0.4 bar at 800- 900 deg C. PCA analysis was used for finding dependency between fuel properties and the convention of fuel-N to NO{sub 2}

  10. Effect of acute intraocular pressure elevation on the minimum rim width in normal, ocular hypertensive and glaucoma eyes.

    Science.gov (United States)

    Sharma, Sourabh; Tun, Tin A; Baskaran, Mani; Atalay, Eray; Thakku, Sri Gowtham; Liang, Zhang; Milea, Dan; Strouthidis, Nicholas G; Aung, Tin; Girard, Michael Ja

    2018-01-01

    To estimate and compare changes in the Bruch's membrane opening-minimum rim width (BMO-MRW) and area in normal, ocular hypertensive and glaucoma eyes following acute elevations in intraocular pressure (IOP). The optic nerve heads (ONHs) of 104 subjects (31 normals, 20 ocular hypertension (OHT) and 53 with primary glaucoma) were imaged using Spectral-domain optical coherence tomography (OCT; Spectralis, Heidelberg Engineering, Germany). IOP was raised twice by applying a force (0.64 n then 0.9 n) to the anterior sclera using an ophthalmo-dynamometer. After each IOP increment, IOP was held constant, measured with a Tonopen (AVIA applanation tonometer, Reichert, Depew, New York, USA), and ONH was rescanned with OCT. In each OCT volume, BMO-MRW and area were calculated and at each IOP increment. The baseline MRW was significantly smaller in glaucoma subjects (174.3±54.3 µm) compared with normal (287.4±42.2 µm, pglaucoma subjects was significantly thinner at the first and second IOP elevations than that at baseline (both p0.05). Acute IOP elevation leads to compression of the nerve fibre layers of neuroretinal rim in glaucoma subjects only without changing ONH size. This suggests that the neural and connective tissues at ONH level in glaucoma subjects are more susceptible to acute IOP episodes than OHT or normal controls. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Specific Features of Structural-Phase State and Properties of Reactor Pressure Vessel Steel at Elevated Irradiation Temperature

    Directory of Open Access Journals (Sweden)

    E. A. Kuleshova

    2017-01-01

    Full Text Available This paper considers influence of elevated irradiation temperature on structure and properties of 15Kh2NMFAA reactor pressure vessel (RPV steel. The steel is investigated after accelerated irradiation at 300°C (operating temperature of VVER-1000-type RPV and 400°C supposed to be the operating temperature of advanced RPVs. Irradiation at 300°C leads to formation of radiation-induced precipitates and radiation defects-dislocation loops, while no carbide phase transformation is observed. Irradiation at a higher temperature (400°C neither causes formation of radiation-induced precipitates nor provides formation of dislocation loops, but it does increase the number density of the main initial hardening phase—of the carbonitrides. Increase of phosphorus concentration in grain boundaries is more pronounced for irradiation at 400°C as compared to irradiation at 300°C due to influence of thermally enhanced diffusion at a higher temperature. The structural-phase changes determine the changes of mechanical properties: at both irradiation temperatures irradiation embrittlement is mainly due to the hardening mechanism with some contribution of the nonhardening one for irradiation at 400°C. Lack of formation of radiation-induced precipitates at T = 400°C provides a small ΔTK shift (17°C. The obtained results demonstrate that the investigated 15Kh2NMFAA steel may be a promising material for advanced reactors with an elevated operating temperature.

  12. Separating the roles of nitrogen and oxygen in high pressure-induced blood-borne microparticle elevations, neutrophil activation, and vascular injury in mice.

    Science.gov (United States)

    Yang, Ming; Bhopale, Veena M; Thom, Stephen R

    2015-08-01

    An elevation in levels of circulating microparticles (MPs) due to high air pressure exposure and the associated inflammatory changes and vascular injury that occur with it may be due to oxidative stress. We hypothesized that these responses arise due to elevated partial pressures of N2 and not because of high-pressure O2. A comparison was made among high-pressure air, normoxic high-pressure N2, and high-pressure O2 in causing an elevation in circulating annexin V-positive MPs, neutrophil activation, and vascular injury by assessing the leakage of high-molecular-weight dextran in a murine model. After mice were exposed for 2 h to 790 kPa air, there were over 3-fold elevations in total circulating MPs as well as subgroups bearing Ly6G, CD41, Ter119, CD31, and CD142 surface proteins-evidence of neutrophil activation; platelet-neutrophil interaction; and vascular injury to brain, omentum, psoas, and skeletal muscles. Similar changes were found in mice exposed to high-pressure N2 using a gas mixture so that O2 partial pressure was the same as that of ambient air, whereas none of these changes occurred after exposures to 166 kPa O2, the same partial pressure that occurs during high-pressure air exposures. We conclude that N2 plays a central role in intra- and perivascular changes associated with exposure to high air pressure and that these responses appear to be a novel form of oxidative stress. Copyright © 2015 the American Physiological Society.

  13. Turbulent burning characteristics of FACE-C gasoline and TPRF blend associated with the same RON at elevated pressures

    KAUST Repository

    Mannaa, Ossama

    2018-04-06

    Fuels for Advanced Combustion Engine (FACE)-C gasoline/air and toluene primary reference fuel (TPRF) (51.6 vol% iso-octane, 21.5 vol% n-heptane and 26.9 vol% toluene)/air mixtures corresponding to the same Research Octane numbers (RON) of 85 were characterized in terms of determining their burning rates in a fan stirred turbulent vessel and filmed using a high-speed dual Schlieren imaging technique. Also, a Mie scattering planar laser tomography was employed to characterize the variations of flame morphology induced by the simultaneous existences of different turbulent length scales and the susceptibility to develop cellular structures at elevated pressures (through the Darrieus-Landau instability). Measurements were performed in a well-controlled environment of initial pressures 0.1, 0.5 and 1.0 MPa at a fixed initial temperature of 358 K at a range of measured turbulence intensities from 0.5 to 2.0 m/s. The enhancement of turbulent burning velocity ST as a function of turbulence intensity was evaluated. The absence of bending regime was accounted for based on the size of the vessel and limited range of turbulent intensities investigated in the present work. All the present data were empirically correlated by power-law correlation derived for a different flame-type configuration to test its sensitivity to the geometry and type of the burner investigated.

  14. Elevated blood pressure and its associated risk factors among adolescents of a North Indian City - A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Senthamizh Prasad

    2017-01-01

    Full Text Available Context: Amidst the uncertainty in childhood blood pressure (BP thresholds, besides the ambiguity in levels and duration of BP elevation causing organ damage, hypertension is present in substantial number of asymptomatic children and adolescents with only a few studies disclosing the setup. With projection of deaths due to noncommunicable diseases in 2030 rising to 52 million, it is necessary to know about the knowledge of present adolescents about BP and its modifiable risk factors. Aims: (1 To assess the prevalence of elevated BP among adolescents and to ascertain the associated risk factors. (2 To assess adolescent's knowledge about BP and its modifiable factors. Settings and Design: A community-based cross-sectional study was conducted on school going adolescents of Lucknow, from September 2014 to August 2015. Subjects and Methods: BP, height, and weight were measured following standard protocols, Centers for Disease Control and Prevention charts for finding respective cut-off values and oral questionnaire for assessing lifestyle risk factors were used. Statistical Analysis: Chi-square, unpaired t-test, and logistic regression were used. Results: Of the 1041 participants, elevated BP (BP percentile ≥90 was prevalent in 24.2%. On regression, factors such as obesity (adjusted odds ratio [aOR] = 5.8, 95% confidence interval [CI] = 3.6–9.4, low fruit diet (aOR = 3.3, 95% CI = 2.1–5.4, and frequent junk food consumption (aOR = 1.9, 95% CI = 1.3–2.8 raised the odds of elevated BP while it was lowered by being physically active (aOR = 0.67, 95% CI = 0.46–0.97. Of 86.3% of children (n = 898 who were fathomed of BP, only less than third (33% and 21.9% acquainted of BP raising and lowering practices, respectively. Conclusions: Prevalence of high BP is colossal with only a few children knowing its amendable nature. Strenuous efforts targeting detrimental behaviors and imparting the sense of healthy lifestyle enhancing practices are vital to

  15. Simultaneous or Early Sequential Rupture of Multiple Intracranial Aneurysms: A Rare and Insufficiently Understood Entity.

    Science.gov (United States)

    Hou, Kun; Zhao, Jinchuan; Zhang, Yang; Zhu, Xiaobo; Zhao, Yan; Li, Guichen

    2016-05-01

    Simultaneous or early sequential rupture of multiple intracranial aneurysms (MIAs) is encountered rarely, with no more than 10 cases having been reported. As a result of its rarity, there are a lot of questions concerning this entity need to be answered. A 67-year-old woman was admitted to the First Hospital of Jilin University (Eastern Division) from a local hospital after a sudden onset of severe headache, nausea, and vomiting. Head computed tomography (CT) at the local hospital revealed diffuse subarachnoid hemorrhage (SAH) that was concentrated predominately in the suprasellar cistern and interhemispheric fissure. During her transfer to our hospital, she experienced another episode of sudden headache. CT on admission to our hospital revealed that the SAH was increased with 2 isolated hematomas both in the interhemispheric fissure and the left paramedian frontal lobe. Further CT angiography and intraoperative findings were in favor of early sequential rupture of 2 intracranial aneurysms. To further elucidate the characteristics, mechanism, management, and prognosis of this specific entity, we conducted a comprehensive review of the literature. The mechanism of simultaneous or early sequential rupture of MIAs is still obscure. Transient elevation of blood pressure might play a role in the process, and preventing the sudden elevation of blood pressure might be beneficial for patients with aneurysmal SAH and MIAs. The management of simultaneously or early sequentially ruptured aneurysms is more complex for its difficulty in responsible aneurysm determination, urgency in treatment, toughness in intraoperative manipulation and poorness in prognosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

    Science.gov (United States)

    ... cause is determined and is referred to as “secondary” intracranial hypertension. What are the risk factors for idiopathic intracranial ... clotting disorders, anemia and malnutrition. Can idiopathic intracranial ... to be “secondary” which affects males and females equally. The second ...

  17. Idiopathic intracranial hypertension

    DEFF Research Database (Denmark)

    Yri, Hanne M; Jensen, Rigmor H

    2015-01-01

    AIMS: The aims of this article are to characterize the headache in idiopathic intracranial hypertension (IIH) and to field-test the ICHD diagnostic criteria for headache attributed to IIH. MATERIALS AND METHODS: We included 44 patients with new-onset IIH. Thirty-four patients with suspected but u...... tinnitus may suggest intracranial hypertension. Based on data from a well-defined IIH cohort, we propose a revision of the ICDH-3 beta diagnostic criteria with improved clinical applicability and increased sensitivity and specificity....

  18. Low vapour pressure deficit reduces the beneficial effect of elevated CO{sub 2} on growth of N{sub 2}-fixing alfalfa plants

    Energy Technology Data Exchange (ETDEWEB)

    Luis, I. De; Irigoyen, J.J.; Sanchez-Diaz, M. [Univ. de Navarra, Dept. de Fisioligia Vegetal, Pamplona (Spain)

    2002-11-01

    Plant responses to elevated CO{sub 2} can be modified by many environmental factors, but very little attention has been paid to the interaction between CO{sub 2} and changes in vapour pressure deficit (VPD). Thirty-day-old alfalfa plants (Medicago sativa L. cv. Aragon), which were inoculated with Sinorhizobium meliloti 102F78 strain, were grown for 1 month in controlled environment chambers at 25/15 deg C, 14 h photoperiod, and 600 mol m{sup -2} s{sup -1} photosynthetic photon flux (PPF), using a factorial combination of CO{sub 2} concentration (400 mol mol{sup -1} or 700 mol mol{sup -1}) and vapour pressure deficit (0.48 kPa or 1.74 kPa, which corresponded to relative humidities of 85% and 45% at 25 deg C, respectively). Elevated CO{sub 2} strongly stimulated plant growth under high VPD conditions, but this beneficial effect was not observed under low VPD. Under low VPD, elevated CO{sub 2} also did not enhance plant photosynthesis, and plant water stress was greatest for plants grown at elevated CO{sub 2} and low VPD. Moreover, plants grown under elevated CO{sub 2} and low VPD had a lower leaf soluble protein and photosynthetic activity (photosynthetic rate and carboxylation efficiency) than plants grown under elevated CO{sub 2} and high VPD. Elevated CO{sub 2} significantly increased leaf adaxial and abaxial temperatures. Because the effects of elevated CO{sub 2} were dependent on vapour pressure deficit, VPD needs to be controlled in experiments studying the effect of elevated CO{sub 2} as well as considered in the extrapolations of results to a warmer, high-CO{sub 2} world. (au)

  19. Intraspinal Pressure Monitoring in a Patient with Spinal Cord Injury Reveals Different Intradural Compartments: Injured Spinal Cord Pressure Evaluation (ISCoPE) Study.

    OpenAIRE

    Phang, I; Papadopoulos, MC

    2015-01-01

    BACKGROUND: We recently described a technique for monitoring intraspinal pressure (ISP) after traumatic spinal cord injury (TSCI). This is analogous to intracranial pressure monitoring after brain injury. We showed that, after severe TSCI, ISP at the injury site is elevated as the swollen cord is compressed against the dura. METHODS: In a patient with complete thoracic TSCI, we sequentially monitored subdural ISP above the injury, at the injury site, and below the injury intraoperatively. Pos...

  20. Dietary sodium restriction reverses vascular endothelial dysfunction in middle-aged/older adults with moderately elevated systolic blood pressure

    Science.gov (United States)

    Jablonski, Kristen L.; Racine, Matthew L.; Geolfos, Candace J.; Gates, Phillip E.; Chonchol, Michel; McQueen, Matthew B.; Seals, Douglas R.

    2013-01-01

    Objectives We determined the efficacy of dietary sodium restriction (DSR) for improving vascular endothelial dysfunction in middle-aged/older adults with moderately elevated systolic blood pressure (SBP; 130–159 mmHg) and the associated physiological mechanisms. Background Vascular endothelial dysfunction develops with advancing age and elevated SBP, contributing to increased cardiovascular risk. DSR lowers BP, but its effect on vascular endothelial function and mechanisms involved are unknown. Methods Seventeen subjects (11M/6F; 62±7 yrs, mean±S.D.) completed a randomized, crossover study of 4 weeks of both low and normal sodium intake. Vascular endothelial function (endothelium-dependent dilation; EDD), nitric oxide (NO)/tetrahydrobiopterin (BH4) bioavailability and oxidative stress-associated mechanisms were assessed following each condition. Results Urinary sodium excretion was reduced by ~50% (to 70±30 mmol/day), and conduit (brachial artery flow-mediated dilation [FMDBA]) and resistance (forearm blood flow responses to acetylcholine [FBFACh]) artery EDD were 68% and 42% (peak FBFACh) higher following the low sodium diet (psodium markedly enhanced NO- mediated EDD (greater ΔFBFACh with endothelial NO synthase [eNOS] inhibition) without changing eNOS expression/activation (Ser1177 phosphorylation), restored BH4 bioactivity (less ΔFMDBA with acute BH4), abolished tonic superoxide suppression of EDD (less ΔFMDBA and ΔFBFACh with ascorbic acid infusion), and increased circulating superoxide dismutase activity (p<0.05). These effects were independent of ΔSBP. Other subject characteristics/dietary factors and endothelium-independent dilation were unchanged. Conclusions DSR largely reverses both macro- and microvascular endothelial dysfunction by enhancing NO and BH4 bioavailability and reducing oxidative stress. Our findings support the emerging concept that DSR induces “vascular protection” beyond that attributable to its BP-lowering effects. PMID

  1. Analysis of petrous apex meningocele associated with meningioma. Is there any relation with chronic intracranial hypertension?

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wan-Qun; Huang, Biao; Liang, Chang-Hong [Southern Medical University, The Second School of Clinical Medicine, Guangzhou (China); Guangdong Academy of Medical Sciences, Department of Radiology, Guangdong General Hospital, Guangzhou, Guangdong (China); Feng, Jie-Ying [Nanhai Hospital Affiliated Southern Medical University, Department of Radiology, Foshan, Guangdong (China); Liu, Hong-Jun [Guangdong Academy of Medical Sciences, Department of Radiology, Guangdong General Hospital, Guangzhou, Guangdong (China)

    2018-02-15

    Petrous apex meningocele (PAM) is an uncommon cystic lesion involving the petrous apex. The underlying cause of PAM may be related to chronic elevated intracranial pressure. The aim of the study was to explore the relationship between PAM and meningioma and between PAM and other intracranial hypertension findings. Two hundred seventy-eight consecutive patients with meningiomas were retrospectively studied. Fifty age- and gender-matched controls were also enrolled in this study. The incidence of PAM, empty sella, tortuosity of the optic nerve, and hydrops of optic nerve sheath was evaluated. The maximum width, area, volume of each PAM, or Meckel's cave and volume of meningioma were measured in controls and patients, separately. One hundred fifty-nine (57.19%) patients were detected with coexistent PAMs. One hundred twenty-five patients had bilateral PAMs, 34 had unilateral lesions, and the remaining 119 did not have PAM. Two subjects (4/50) had unilateral PAMs in normal controls. The maximum width, area, volume of PAM, or Meckel's cave were significantly larger in the patients with bilateral PAM group than those in the unilateral PAM group, in the group without PAM, and those in control group (p = 0.000). The volume of meningioma was positively correlated with the PAM volume (r = 0.48). There was a positive correlation for the incidence between PAM and (1) empty sella (r = 0.901) and (2) tortuosity of the optic nerves and hydrops of the optic sheath (r = 0.825). Coexistence of PAMs with meningiomas is not rare in incidence, and it suggests a potential role for chronically elevated intracranial pressure and disturbance of CSF circulation in their pathophysiology. (orig.)

  2. Analysis of petrous apex meningocele associated with meningioma. Is there any relation with chronic intracranial hypertension?

    International Nuclear Information System (INIS)

    Yang, Wan-Qun; Huang, Biao; Liang, Chang-Hong; Feng, Jie-Ying; Liu, Hong-Jun

    2018-01-01

    Petrous apex meningocele (PAM) is an uncommon cystic lesion involving the petrous apex. The underlying cause of PAM may be related to chronic elevated intracranial pressure. The aim of the study was to explore the relationship between PAM and meningioma and between PAM and other intracranial hypertension findings. Two hundred seventy-eight consecutive patients with meningiomas were retrospectively studied. Fifty age- and gender-matched controls were also enrolled in this study. The incidence of PAM, empty sella, tortuosity of the optic nerve, and hydrops of optic nerve sheath was evaluated. The maximum width, area, volume of each PAM, or Meckel's cave and volume of meningioma were measured in controls and patients, separately. One hundred fifty-nine (57.19%) patients were detected with coexistent PAMs. One hundred twenty-five patients had bilateral PAMs, 34 had unilateral lesions, and the remaining 119 did not have PAM. Two subjects (4/50) had unilateral PAMs in normal controls. The maximum width, area, volume of PAM, or Meckel's cave were significantly larger in the patients with bilateral PAM group than those in the unilateral PAM group, in the group without PAM, and those in control group (p = 0.000). The volume of meningioma was positively correlated with the PAM volume (r = 0.48). There was a positive correlation for the incidence between PAM and (1) empty sella (r = 0.901) and (2) tortuosity of the optic nerves and hydrops of the optic sheath (r = 0.825). Coexistence of PAMs with meningiomas is not rare in incidence, and it suggests a potential role for chronically elevated intracranial pressure and disturbance of CSF circulation in their pathophysiology. (orig.)

  3. Variation in monitoring and treatment policies for intracranial hypertension in traumatic brain injury: A survey in 66 neurotrauma centers participating in the CENTER-TBI study

    NARCIS (Netherlands)

    M.C. Cnossen (Maryse); Huijben, J.A. (Jilske A.); van der Jagt, M. (Mathieu); Volovici, V. (Victor); van Essen, T. (Thomas); S. Polinder (Suzanne); D. Nelson (David); Ercole, A. (Ari); Stocchetti, N. (Nino); Citerio, G. (Giuseppe); W.C. Peul (Wilco); A.I.R. Maas (Andrew I.R.); D.K. Menon (David ); E.W. Steyerberg (Ewout W.); Lingsma, H.F. (Hester F.); Adams, H. (Hadie); Alessandro, M. (Masala); J.E. Allanson (Judith); Amrein, K. (Krisztina); Andaluz, N. (Norberto); N. Andelic (Nada); Andrea, N. (Nanni); L. Andreassen (Lasse); Anke, A. (Audny); Antoni, A. (Anna); Ardon, H. (Hilko); Audibert, G. (Gérard); Auslands, K. (Kaspars); Azouvi, P. (Philippe); Baciu, C. (Camelia); Bacon, A. (Andrew); Badenes, R. (Rafael); Baglin, T. (Trevor); R.H.M.A. Bartels (Ronald); P. Barzo (P.); Bauerfeind, U. (Ursula); R. Beer (Ronny); Belda, F.J. (Francisco Javier); B.-M. Bellander (Bo-Michael); A. Belli (Antonio); Bellier, R. (Rémy); H. Benali (Habib); Benard, T. (Thierry); M. Berardino (Maurizio); L. Beretta (Luigi); Beynon, C. (Christopher); Bilotta, F. (Federico); H. Binder (Harald); Biqiri, E. (Erta); Blaabjerg, M. (Morten); Lund, S.B. (Stine Borgen); Bouzat, P. (Pierre); Bragge, P. (Peter); Brazinova, A. (Alexandra); F. Brehar (Felix); Brorsson, C. (Camilla); Buki, A. (Andras); M. Bullinger (Monika); Bucková, V. (Veronika); Calappi, E. (Emiliana); P. Cameron (Peter); Carbayo, L.G. (Lozano Guillermo); Carise, E. (Elsa); K.L.H. Carpenter (Keri L.H.); Castaño-León, A.M. (Ana M.); Causin, F. (Francesco); Chevallard, G. (Giorgio); A. Chieregato (Arturo); G. Citerio (Giuseppe); Cnossen, M. (Maryse); M. Coburn (Mark); J.P. Coles (Jonathan P.); Cooper, J.D. (Jamie D.); Correia, M. (Marta); A. Covic (Amra); N. Curry (Nicola); E. Czeiter (Endre); M. Czosnyka (Marek); Dahyot-Fizelier, C. (Claire); F. Damas (François); P. Damas (Pierre); H. Dawes (Helen); De Keyser, V. (Véronique); F.D. Corte (Francesco); B. Depreitere (Bart); Ding, S. (Shenghao); D.W.J. Dippel (Diederik); K. Dizdarevic (Kemal); Dulière, G.-L. (Guy-Loup); Dzeko, A. (Adelaida); G. Eapen (George); Engemann, H. (Heiko); A. Ercole (Ari); P. Esser (Patrick); Ezer, E. (Erzsébet); M. Fabricius (Martin); V.L. Feigin (V.); Feng, J. (Junfeng); Foks, K. (Kelly); F. Fossi (Francesca); Francony, G. (Gilles); J. Frantzén (Janek); Freo, U. (Ulderico); S.K. Frisvold (Shirin Kordasti); Furmanov, A. (Alex); Gagliardo, P. (Pablo); D. Galanaud (Damien); G. Gao (Guoyi); K. Geleijns (Karin); A. Ghuysen (Alexandre); Giraud, B. (Benoit); Glocker, B. (Ben); Gomez, P.A. (Pedro A.); Grossi, F. (Francesca); R.L. Gruen (Russell); Gupta, D. (Deepak); J.A. Haagsma (Juanita); E. Hadzic (Ermin); I. Haitsma (Iain); J.A. Hartings (Jed); R. Helbok (Raimund); E. Helseth (Eirik); Hertle, D. (Daniel); S. Hill (Sean); Hoedemaekers, A. (Astrid); S. Hoefer (Stefan); P.J. Hutchinson (Peter J.); Håberg, K.A. (Kristine Asta); B.C. Jacobs (Bart); Janciak, I. (Ivan); K. Janssens (Koen); Jiang, J.-Y. (Ji-Yao); Jones, K. (Kelly); Kalala, J.-P. (Jean-Pierre); Kamnitsas, K. (Konstantinos); Karan, M. (Mladen); Karau, J. (Jana); A. Katila (Ari); M. Kaukonen (Maija); Keeling, D. (David); Kerforne, T. (Thomas); N. Ketharanathan (Naomi); Kettunen, J. (Johannes); Kivisaari, R. (Riku); A.G. Kolias (Angelos G.); Kolumbán, B. (Bálint); E.J.O. Kompanje (Erwin); D. Kondziella (Daniel); L.-O. Koskinen (Lars-Owe); Kovács, N. (Noémi); F. Kalovits (Ferenc); A. Lagares (Alfonso); L. Lanyon (Linda); S. Laureys (Steven); Lauritzen, M. (Martin); F.E. Lecky (Fiona); C. Ledig (Christian); R. Lefering; V. Legrand (Valerie); Lei, J. (Jin); L. Levi (Leon); R. Lightfoot (Roger); H.F. Lingsma (Hester); D. Loeckx (Dirk); Lozano, A. (Angels); Luddington, R. (Roger); Luijten-Arts, C. (Chantal); Maas, A.I.R. (Andrew I.R.); MacDonald, S. (Stephen); MacFayden, C. (Charles); M. Maegele (Marc); M. Majdan (Marek); Major, S. (Sebastian); A. Manara (Alex); Manhes, P. (Pauline); G. Manley (Geoffrey); Martin, D. (Didier); C. Martino (Costanza); Maruenda, A. (Armando); H. Maréchal (Hugues); Mastelova, D. (Dagmara); Mattern, J. (Julia); McMahon, C. (Catherine); Melegh, B. (Béla); Menon, D. (David); T. Menovsky (Tomas); Morganti-Kossmann, C. (Cristina); Mulazzi, D. (Davide); Mutschler, M. (Manuel); H. Mühlan (Holger); Negru, A. (Ancuta); Nelson, D. (David); E. Neugebauer (Eddy); V.F. Newcombe (Virginia F.); Noirhomme, Q. (Quentin); Nyirádi, J. (József); M. Oddo (Mauro); A.W. Oldenbeuving; M. Oresic (Matej); Ortolano, F. (Fabrizio); A. Palotie (Aarno); P.M. Parizel; Patruno, A. (Adriana); J.-F. Payen (Jean-François); Perera, N. (Natascha); V. Perlbarg (Vincent); Persona, P. (Paolo); Peul, W. (Wilco); N. Pichon (Nicolas); Piilgaard, H. (Henning); A. Piippo (Anna); S.P. Floury (Sébastien Pili); M. Pirinen (Matti); H. Ples (Horia); Polinder, S. (Suzanne); Pomposo, I. (Inigo); M. Psota (Marek); P. Pullens (Pim); L. Puybasset (Louis); A. Ragauskas (Arminas); R. Raj (Rahul); Rambadagalla, M. (Malinka); Rehorcíková, V. (Veronika); J.K.J. Rhodes (Jonathan K.J.); S. Richardson (Sylvia); S. Ripatti (Samuli); S. Rocka (Saulius); Rodier, N. (Nicolas); Roe, C. (Cecilie); Roise, O. (Olav); C.M.A.A. Roks (Gerwin); Romegoux, P. (Pauline); J. Rosand (Jonathan); Rosenfeld, J. (Jeffrey); C. Rosenlund (Christina); G. Rosenthal (Guy); R. Rossaint (Rolf); S. Rossi (Sandra); Rostalski, T. (Tim); D. Rueckert (Daniel); de Ruiz, A.F. (Arcaute Felix); M. Rusnák (Martin); Sacchi, M. (Marco); Sahakian, B. (Barbara); J. Sahuquillo (Juan); O. Sakowitz (Oliver); Sala, F. (Francesca); Sanchez-Pena, P. (Paola); Sanchez-Porras, R. (Renan); Sandor, J. (Janos); Santos, E. (Edgar); N. Sasse (Nadine); Sasu, L. (Luminita); Savo, D. (Davide); I.B. Schipper (Inger); Schlößer, B. (Barbara); S. Schmidt (Silke); Schneider, A. (Annette); H. Schoechl (Herbert); G.G. Schoonman; Rico, F.S. (Frederik Schou); E. Schwendenwein (Elisabeth); Schöll, M. (Michael); Sir, O. (özcan); T. Skandsen (Toril); Smakman, L. (Lidwien); D. Smeets (Dominique); Smielewski, P. (Peter); Sorinola, A. (Abayomi); E. Stamatakis (Emmanuel); S. Stanworth (Simon); Stegemann, K. (Katrin); Steinbüchel, N. (Nicole); R. Stevens (Robert); W. Stewart (William); E.W. Steyerberg (Ewout); N. Stocchetti (Nino); Sundström, N. (Nina); Synnot, A. (Anneliese); J. Szabó (József); J. Söderberg (Jeannette); F.S. Taccone (Fabio); Tamás, V. (Viktória); Tanskanen, P. (Päivi); A. Tascu (Alexandru); Taylor, M.S. (Mark Steven); Te, A.B. (Ao Braden); O. Tenovuo (Olli); Teodorani, G. (Guido); A. Theadom (Alice); Thomas, M. (Matt); D. Tibboel (Dick); C.M. Tolias (Christos M.); Tshibanda, J.-F.L. (Jean-Flory Luaba); Tudora, C.M. (Cristina Maria); P. Vajkoczy (Peter); Valeinis, E. (Egils); Hecke, W.V. (Wim Van); Praag, D.V. (Dominique Van); Dirk, V.R. (Van Roost); Vlierberghe, E.V. (Eline Van); Vyvere, T.V. (Thijs vande); Vanhaudenhuyse, A. (Audrey); A. Vargiolu (Alessia); E. Vega (Emmanuel); J. Verheyden (Jan); Vespa, P.M. (Paul M.); A. Vik (Anne); R. Vilcinis (Rimantas); Vizzino, G. (Giacinta); C.L.A.M. Vleggeert-Lankamp (Carmen); V. Volovici (Victor); P. Vulekovic (Peter); Vámos, Z. (Zoltán); Wade, D. (Derick); Wang, K.K.W. (Kevin K.W.); Wang, L. (Lei); E.D. Wildschut (Enno); G. Williams (Guy); Willumsen, L. (Lisette); Wilson, A. (Adam); Wilson, L. (Lindsay); Winkler, M.K.L. (Maren K.L.); P. Ylén (Peter); Younsi, A. (Alexander); M. Zaaroor (Menashe); Zhang, Z. (Zhiqun); Zheng, Z. (Zelong); Zumbo, F. (Fabrizio); de Lange, S. (Stefanie); G.C.W. De Ruiter (Godard C.W.); den Boogert, H. (Hugo); van Dijck, J. (Jeroen); T.A. van Essen (T.); C.M. van Heugten (Caroline M.); M. van der Jagt (Mathieu); J. van der Naalt (Joukje)

    2017-01-01

    textabstractBackground: No definitive evidence exists on how intracranial hypertension should be treated in patients with traumatic brain injury (TBI). It is therefore likely that centers and practitioners individually balance potential benefits and risks of different intracranial pressure (ICP)

  4. Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure.

    Science.gov (United States)

    Wojnarowska, Z; Swiety-Pospiech, A; Grzybowska, K; Hawelek, L; Paluch, M; Ngai, K L

    2012-04-28

    The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M(")(f) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across T(g). The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below T(g). At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found

  5. Sinogenic intracranial complications

    DEFF Research Database (Denmark)

    Kofoed, Mikkel Seremet; Fisker, Niels; Christensen, Anne Estmann

    2018-01-01

    We present two 11-year-old girls with chronic recurrent multifocal osteomyelitis, treated with adalimumab. Both developed severe intracranial complications to sinusitis. Patient 1 had been treated with adalimumab for 15 months when she developed acute sinusitis complicated by an orbital abscess, ...

  6. Intracranial tuberculoma: MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, P; Zenteno, M A; Rodriguez-Carbajal, J; Brutto, O.H. del; Talamas, O

    1989-09-01

    MR studies of 6 patients with intracranial tuberculoma are reviewed. All patients also underwent CT scans which showed hypo- or isodense lesions with abnormal enhancement following contrast administration. MR showed lesions with prolongation of the T1 relaxation time in every case. On the T2-weighted sequences, the signal properties of the tuberculoma varied according to the stage of evolution of the lesion. Incipient tuberculomas appeared as scattered areas of hypointensity surrounded by edema. Mature tuberculomas were composed of a dark necrotic center surrounded by an isointense capsule which was, in turn, surrounded by edema. In one patient, the center of the lesion was hyperintense probably because of liquefaction and pus formation (tuberculous abscess). While both, CT and MR, were equally sensitive in visualizing the intracranial tuberculoma in every patient, MR was slightly superior in demonstrating the extent of the lesion, especially for brainstem tuberculomas. Nevertheless, the potential role for MR diagnosis of intracranial tuberculoma is limited by the fact that other infectious or neoplasic diseases may present similar findings. The diagnosis of intracranial tuberculoma should rest on a proper integration of data from clinical manifestations, cerebrospinal fluid analysis, and neuroimaging studies. (orig.).

  7. Intracranial tuberculoma: MR imaging

    International Nuclear Information System (INIS)

    Salgado, P.; Zenteno, M.A.; Rodriguez-Carbajal, J.; Brutto, O.H. del; Talamas, O.

    1989-01-01

    MR studies of 6 patients with intracranial tuberculoma are reviewed. All patients also underwent CT scans which showed hypo- or isodense lesions with abnormal enhancement following contrast administration. MR showed lesions with prolongation of the T1 relaxation time in every case. On the T2-weighted sequences, the signal properties of the tuberculoma varied according to the stage of evolution of the lesion. Incipient tuberculomas appeared as scattered areas of hypointensity surrounded by edema. Mature tuberculomas were composed of a dark necrotic center surrounded by an isointense capsule which was, in turn, surrounded by edema. In one patient, the center of the lesion was hyperintense probably because of liquefaction and pus formation (tuberculous abscess). While both, CT and MR, were equally sensitive in visualizing the intracranial tuberculoma in every patient, MR was slightly superior in demonstrating the extent of the lesion, especially for brainstem tuberculomas. Nevertheless, the potential role for MR diagnosis of intracranial tuberculoma is limited by the fact that other infectious or neoplasic diseases may present similar findings. The diagnosis of intracranial tuberculoma should rest on a proper integration of data from clinical manifestations, cerebrospinal fluid analysis, and neuroimaging studies. (orig.)

  8. Endovascular treatment of intracranial venous sinus thrombosis

    International Nuclear Information System (INIS)

    Xu Shubin; Liang Zhihui; Cui Jinguo; Tian Huiqin; Li Liang; Chen Feng

    2009-01-01

    Objective: To evaluate the clinical efficacy and safety of endovascular treatment for intracranial venous sinus thrombosis. Methods: Ten patients with intracranial venous sinus thrombosis, confirmed by CT, MRI, MRV and / or DSA and encountered during the period of Aug. 2005-Aug. 2007, were treated with endovascular management after they failed to respond to anticoagulant therapy. Of ten patients, intravenous thrombolysis and mechanical thrombus maceration were carried out in 6, while intravenous thrombolysis, mechanical thrombus maceration together with intra-arterial thrombolysis were employed in 4. After the treatment, the anticoagulant therapy continued for 6 months. The patients were followed up for 12-29 months (mean 21 months). Results: After the treatment, the clinical symptoms and signs were completely or partially relieved in eight patients, including disappearance of headache (n=6) and relive of headache (n=2). No obvious improvement was found in one patient and linguistic function disturbance was seen in the remaining one. Lumbar puncture showed that the cerebrospinal fluid pressure returned to normal in all patients. Neither recurrence of thrombosis nor new symptom of neuralgic dysfunction was observed. No procedure-related intracranial or systemic hemorrhagic complications occurred both during and after the operation. Conclusion: Endovascular treatment is an effective and safe procedure for the potentially catastrophic intracranial venous thrombosis. (authors)

  9. Influence of bushenhuoxue on primary visual cortex' BDNF damage in rat model of chronic elevated intraocular pressure

    Directory of Open Access Journals (Sweden)

    Xiang Li

    2013-04-01

    Full Text Available AIM: To observe the effect of traditional Chinese medicine(TCMof bushenhuoxue on primary visual cortex(PVCbrain-derived neurotrophic factor(BDNFin rat model of chronic elevated intraocular pressure(EIOP, and explore the mechanism of it initially. METHODS: The rat model of chronic EIOP was established by unilaterally cauterizing 3 episcleral veins, then 30 rats were divided into 3 groups randomly: control group, model group, and treatment group. After given drugs or normal saline for 8 weeks, the rats were put to death. The effect of intraocular pressure(IOP, expression of BDNF and ultrastructure of neuron cell in the PVC was observed. RESULTS: Unilaterally cauterizing episcleral veins increased IOP of the rat model obviously, there was significant difference compared with pre-operation(P<0.01. Semi-quantitative pathological analysis on PVC showed that BDNF of total area in the model group was(82438±2597.39S/μm2,mean optical density was(1155.9±123.14, integrated optical density was(12915±673.28, compared with the control group {total area was(132370±7588.47S/μm2, mean optical density was(5365±379.65, integrated optical density was(35102±2648.5}, there were statistical differences(all P<0.05,there was statistical difference in BDNF of total area between model group and treatment group{(108980±9126.77S/μm2, P<0.05}, significant difference in mean optical density between the model group and treatment group(3220.4±413.67, P<0.05, statistical difference in integrated optical density between the model group and treatment group(23821±3431.68, P<0.05. CONCLUSION: TCM of bushenhuoxue can repair the PVC damage in the rat model of chronic EIOP by enhancing expression of BDNF, improving ultrastructure of neuron cell.

  10. Vagal Blocking Improves Glycemic Control and Elevated Blood Pressure in Obese Subjects with Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    S. Shikora

    2013-01-01

    Full Text Available Background. An active device that downregulates abdominal vagal signalling has resulted in significant weight loss in feasibility studies. Objective. To prospectively evaluate the effect of intermittent vagal blocking (VBLOC on weight loss, glycemic control, and blood pressure (BP in obese subjects with DM2. Methods. Twenty-eight subjects were implanted with a VBLOC device (Maestro Rechargeable System at 5 centers in an open-label study. Effects on weight loss, HbA1c, fasting blood glucose, and BP were evaluated at 1 week to 12 months. Results. 26 subjects (17 females/9 males, 51±2 years, BMI 37±1 kg/m2, mean ± SEM completed 12 months followup. One serious adverse event (pain at implant site was easily resolved. At 1 week and 12 months, mean excess weight loss percentages (% EWL were 9±1% and 25±4% (P<0.0001, and HbA1c declined by 0.3±0.1% and 1.0±0.2% (P=0.02, baseline 7.8±0.2%. In DM2 subjects with elevated BP (n=15, mean arterial pressure reduced by 7±3 mmHg and 8±3 mmHg (P=0.04, baseline 100 ± 2 mmHg at 1 week and 12 months. All subjects MAP decreased by 3 ± 2 mmHg (baseline 95 ± 2 mmHg at 12 months. Conclusions. VBLOC was safe in obese DM2 subjects and associated with meaningful weight loss, early and sustained improvements in HbA1c, and reductions in BP in hypertensive DM2 subjects. This trial is registered with ClinicalTrials.gov NCT00555958.

  11. Dynamic modeling of uteroplacental blood flow in IUGR indicates vortices and elevated pressure in the intervillous space - a pilot study

    Science.gov (United States)

    Roth, Christian J.; Haeussner, Eva; Ruebelmann, Tanja; Koch, Franz V.; Schmitz, Christoph; Frank, Hans-Georg; Wall, Wolfgang A.

    2017-01-01

    Ischemic placental disease is a concept that links intrauterine growth retardation (IUGR) and preeclampsia (PE) back to insufficient remodeling of uterine spiral arteries. The rheological consequences of insufficient remodeling of uterine spiral arteries were hypothesized to mediate the considerably later manifestation of obstetric disease. However, the micro-rheology in the intervillous space (IVS) cannot be examined clinically and rheological animal models of the human IVS do not exist. Thus, an in silico approach was implemented to provide in vivo inaccessible data. The morphology of a spiral artery and the inflow region of the IVS were three-dimensionally reconstructed to provide a morphological stage for the simulations. Advanced high-end supercomputing resources were used to provide blood flow simulations at high spatial resolution. Our simulations revealed turbulent blood flow (high-velocity jets and vortices) combined with elevated blood pressure in the IVS and increased wall shear stress at the villous surface in conjunction with insufficient spiral artery remodeling only. Post-hoc histological analysis of uterine veins showed evidence of increased trophoblast shedding in an IUGR placenta. Our data support that rheological alteration in the IVS is a relevant mechanism linking ischemic placental disease to altered structural integrity and function of the placenta.

  12. Entrained-flow gasification at elevated pressure: Volume 1: Final technical report, March 1, 1985-April 30,1987

    Energy Technology Data Exchange (ETDEWEB)

    Hedman, P.O.; Smoot, L.D.; Smith, P.J.; Blackham, A.U.

    1987-10-15

    The general purpose of this research program was to develop a basic understanding of the physical and chemical processes in entrained coal gasification and to use the results to improve and evaluate an entrained gasification computer model. The first task included the collection and analysis of in-situ gasifier data at elevated pressures with three coal types (North Dakota lignite, Wyoming subbituminous and Illinois bituminous), the design, construction, and testing of new coal/oxygen/steam injectors with a fourth coal type (Utah bituminous), the collection of supporting turbulent fluid dynamic (LDV) data from cold-flow studies, and the investigation of the feasibility of using laser-based (CARS) daignostic instruments to make measurements in coal flames. The second task included improvements to the two-dimensional gasifier submodels, tabulation and evaluation of new coal devolatilization and char oxidation data for predictions, fundamental studies of turbulent particle dispersion, the development of improved numerical methods, and validation of the comprehensive model through comparison of predictions with experimental results. The third task was to transfer technical advances to industry and to METC through technical seminars, production of a detailed data book, code placement, and publication of results. Research results for these three tasks are summarized briefly here and presented in detail in the body of the report and in supporting references. 202 refs., 73 figs., 23 tabs.

  13. Variations in dark respiration and mitochondrial numbers within needles of Pinus radiata grown in ambient or elevated CO2 partial pressure

    International Nuclear Information System (INIS)

    Griffin, K. L.; Anderson, O. R.; Tissue, D. T.; Turnbull, M. H.; Whitehead, D.

    2004-01-01

    An experiment involving comparison of within-leaf variations in cell size, mitochondrial numbers and dark respiration in the most recently expanded tip, the mid-section and the base of needles of Pinus radiata grown for four years at ambient and elevated carbon dioxide partial pressure, is described. Results showed variation in mitochondrial numbers and respiration along the length of the needle, with the highest number of mitochondria per unit cytoplasm and the highest rate of respiration per unit leaf area at the base of the needle. Elevated carbon dioxide pressure caused the number of mitochondria per unit cytoplasm to double regardless of location (tip, basal or mid sections). Under these conditions, greatest mitochondrial density was observed at the tip. The mean size of mitochondria was not affected by either growth at elevated carbon dioxide pressure or by position on the needle. Respiration per unit leaf area at elevated carbon dioxide pressure was highest at the tip of needles, decreasing towards the middle and basal sections. The observed data supports the hypothesis that the highest number of mitochondria per unit area of cytoplasm occurs at the base of the needle, but does not support the hypothesis that the lowest rate of respiration also occurs at the base. It is suggested that the relationship that determines the association between structure and function in these needles is more complex than previously thought. 33 refs., 4 tabs., 1 fig

  14. The Significance of Arachnoid Granulation in Patients With Idiopathic Intracranial Hypertension.

    Science.gov (United States)

    Watane, Gaurav Vishwasrao; Patel, Bhumi; Brown, Derek; Taheri, M Reza

    The aim of this article was to study the significance of arachnoid granulations (AGs) in patients with idiopathic intracranial hypertension (IIH). In an institutional review board-approved retrospective chart review study, 79 patients with clinical diagnosis of idiopathic increased intracranial pressure were compared with 63 patients with a diagnosis of multiple sclerosis. Inclusion criteria also included available magnetic resonance imaging (MRI) of the brain, older than 18 years, and female sex. Patients with elevated intracranial pressure due to other causes were excluded. The electronic medical records were mined for presence of the following: body mass index, age, headache, vision changes, tinnitus, and vertigo. The MRI of the brain was reviewed for the presence of the following features: empty sella, prominent cerebrospinal fluid space in the optic sheaths, tortuosity of the optic nerves and enlarged Meckel cave. In addition, the number, size, and location of AGs associated with major venous drainage sinuses were documented in all patients. Using statistical analysis, association between various imaging and clinical signs were evaluated. The association between AG and various imaging and clinical signs were evaluated. The percentage of patients with AG were significantly higher in patients with IIH. Patients with IIH tended to have 0 to 3 AG. The most common imaging findings observed in MRI of the brain of patients with IIH were empty sella and prominent cerebrospinal fluid space in the optic sheaths. The prevalence of these MRI findings in patients with IIH was inversely proportional to the number of AG. A similar inverse trend was also noted with the opening pressure of patients with IIH and number of AG. The study establishes that there is a relationship between presence of AG and IIH. Arachnoid granulation seems to act in a compensatory mechanism in patients with IIH.

  15. Osmolality of Cerebrospinal Fluid from Patients with Idiopathic Intracranial Hypertension (IIH.

    Directory of Open Access Journals (Sweden)

    Elisabeth A Wibroe

    Full Text Available Idiopathic intracranial hypertension (IIH is a disorder of increased intracranial fluid pressure (ICP of unknown etiology. This study aims to investigate osmolality of cerebrospinal fluid (CSF from patients with IIH.We prospectively collected CSF from individuals referred on suspicion of IIH from 2011-2013. Subjects included as patients fulfilled Friedman and Jacobson's diagnostic criteria for IIH. Individuals in whom intracranial hypertension was refuted were included as controls. Lumbar puncture with ICP measurement was performed at inclusion and repeated for patients after three months of treatment. Osmolality was measured with a Vapor Pressure Osmometer.We collected 90 CSF samples from 38 newly diagnosed patients and 28 controls. At baseline 27 IIH-samples and at 3 months follow-up 35 IIH-samples were collected from patients. We found no significant differences in osmolality between 1 patients at baseline and controls (p = 0. 86, 2 patients at baseline and after 3 months treatment (p = 0.97, and 3 patients with normalized pressure after 3 months and their baseline values (p = 0.79. Osmolality in individuals with normal ICP from 6-25 cmH2O (n = 41 did not differ significantly from patients with moderately elevated ICP from 26-45 cmH2O (n = 21 (p = 0.86 and patients with high ICP from 46-70 cmH2O (n = 4 (p = 0.32, respectively. There was no correlation between osmolality and ICP, BMI, age and body height, respectively. Mean CSF osmolality was 270 mmol/kg (± 1 SE, 95% confidence interval 267-272 for both patients and controls.CSF osmolality was normal in patients with IIH, and there was no relation to treatment, ICP, BMI, age and body height. Mean CSF osmolality was 270 mmol/kg and constitutes a reference for future studies. Changes in CSF osmolality are not responsible for development of IIH. Other underlying pathophysiological mechanisms must be searched.

  16. Spontaneous Intracranial Hypotension

    International Nuclear Information System (INIS)

    Joash, Dr.

    2015-01-01

    Epidemiology is not only rare but an important cause of new daily persistent headaches among young & middle age individuals. The Etiology & Pathogenesis is generally caused by spinal CSF leak. Precise cause remains largely unknown, underlying structural weakness of spinal meninges is suspected. There are several MR Signs of Intracranial Hypotension that include:- diffuse pachymeningeal (dural) enhancement; bilateral subdural, effusion/hematomas; Downward displacement of brain; enlargement of pituitary gland; Engorgement of dural venous sinuses; prominence of spinal epidural venous plexus and Venous sinus thrombosis & isolated cortical vein thrombosis. The sum of volumes of intracranial blood, CSF & cerebral tissue must remain constant in an intact cranium. Treatment in Many cases can be resolved spontaneously or by use Conservative approach that include bed rest, oral hydration, caffeine intake and use of abdominal binder. Imaging Modalities for Detection of CSF leakage include CT myelography, Radioisotope cisternography, MR myelography, MR imaging and Intrathecal Gd-enhanced MR

  17. Intracranial cavernous angioma

    International Nuclear Information System (INIS)

    Yuhi, Fumiaki; Gondou, Masazumi; Sasahira, Masahiro; Ichitsubo, Hidenori; Asakura, Tetsuhiko.

    1986-01-01

    The present authors have experienced 2 cases of intracranial cavernous angioma. Of these cases, one was admitted because of generalized convulsions, while the other was admitted because of headache. In both cases, neither plain X-ray films nor carotid angiography showed any abnormality, but computerized tomography (CT) revealed a slightly high-density area which was not enhanced with contrast media. Histologically, the tumors had many vascular cavities with walls lined with a single layer of endothelial cells and had no neural tissue between the vascular cavities; therefore, they were diagnosed as cases of cavernous angioma. The authors discussed the radiological findings of the intracranial cavernous angioma with a review of the literature and stressed the role of computerized tomography in the diagnosis of cavernous angioma. (author)

  18. Intracranial Atherosclerotic Disease

    Directory of Open Access Journals (Sweden)

    Maria Khan

    2011-01-01

    Full Text Available Intracranial atherosclerotic disease (ICAD is the most common proximate mechanism of ischemic stroke worldwide. Approximately half of those affected are Asians. For diagnosis of ICAD, intra-arterial angiography is the gold standard to identify extent of stenosis. However, noninvasive techniques including transcranial ultrasound and MRA are now emerging as reliable modalities to exclude moderate to severe (50%–99% stenosis. Little is known about measures for primary prevention of the disease. In terms of secondary prevention of stroke due to intracranial atherosclerotic stenosis, aspirin continues to be the preferred antiplatelet agent although clopidogrel along with aspirin has shown promise in the acute phase. Among Asians, cilostazol has shown a favorable effect on symptomatic stenosis and is of benefit in terms of fewer bleeds. Moreover, aggressive risk factor management alone and in combination with dual antiplatelets been shown to be most effective in this group of patients. Interventional trials on intracranial atherosclerotic stenosis have so far only been carried out among Caucasians and have not yielded consistent results. Since the Asian population is known to be preferentially effected, focused trials need to be performed to establish treatment modalities that are most effective in this population.

  19. Intracranial MR angiography

    International Nuclear Information System (INIS)

    Davis, W.L.; Blatter, D.D.; Parker, D.L.; Robison, R.O.; Harnsberger, H.R.

    1991-01-01

    This paper compares the more traditional three-dimensional (3D) time-of-flight MR angiography with a novel new technique, MOTSA, in the evaluation of both normal and abnormal intracranial anatomy. The authors performed sequential, location-matched 3D TOF and MOTSA MR angiography in 10 subjects with normal and 25 with abnormal intracranial anatomy. Images were evaluated for visualization of specific vessels and depiction of pathologic anatomy. All images were subjected to an objective scoring system. Digital angiography was available in 15 of 25 abnormal cases. In the normal cases, large- and small-vessel visualization was improved. Significant improvement in visualization of venous anatomy was also observed. In the abnormal cases, pathologic anatomy was better visualized, providing important diagnostic information. Multiple overlapping thin-slab-acquisition MR angiography demonstrates vessel visualization that is increased over that of 3D TOF MR angiography in both normal and abnormal cases. Because of the decrease in saturation effects and phase dispersion, MOTSA is especially useful in the evaluation of complex intracranial vascular abnormalities

  20. Low physical activity is a determinant for elevated blood pressure in high cardiovascular risk obstructive sleep apnea.

    Science.gov (United States)

    Mendelson, Monique; Tamisier, Renaud; Laplaud, David; Dias-Domingos, Sonia; Baguet, Jean-Philippe; Moreau, Laurent; Koltes, Christian; Chavez, Léonidas; de Lamberterie, Gilles; Herengt, Frédéric; Levy, Patrick; Flore, Patrice; Pépin, Jean-Louis

    2014-08-01

    Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity, including hypertension. Beyond the severity of nocturnal hypoxia, other factors such as metabolic abnormalities but also sedentary behaviors and insufficient physical activity may contribute to elevated blood pressure (BP). To clarify the respective role of these factors as determinants of BP in OSA patients, we examined the relationship between BP and anthropometrics, severity of sleep apnea, and objectively measured physical activity and sedentary behaviors. Ninety-five adults presenting with OSA (apnea-hypopnea index > 10 events/h) and high cardiovascular risk (63.3 ± 8.8 y; body mass index: 29.9 ± 4.9 kg/m(2); apnea-hypopnea index: 41.3 ± 17.5/h; cardiovascular risk score: 13.5 ± 3.7%) were included. Physical activity and sedentary behaviors were objectively assessed by actigraphy, and self-measured home BP monitoring was measured. Logistic regression models adjusted for sex, age, and body mass index were built to identify the predictors of self-measured morning and evening BP. Physical activity was significantly related to obesity but not to the severity of sleep apnea or sleepiness. Sedentary behaviors were associated with self-measured morning and evening systolic BP (r = 0.32, P = .002; r = 0.29, P = .004). Steps per day were inversely associated with evening BP (r = -0.27, P = .01). Univariate analysis identified steps/d and time spent in vigorous physical activity as determinants for evening self-measured BP. In multivariate analysis, only steps/d were identified as a significant determinant of evening BP. Physical activity is the major determinant for evening BP in adults with OSA presenting high cardiovascular risk. Our results emphasize the need for lifestyle counseling programs in combination with CPAP to encourage regular physical activity in OSA subjects to obtain better BP control. (ClinicalTrials.gov registration NCT01226641.)

  1. Ahmed Versus Baerveldt Glaucoma Drainage Implantation in Patients With Markedly Elevated Intraocular Pressure (≥30 mm Hg).

    Science.gov (United States)

    Resende, Arthur F; Moster, Marlene R; Patel, Neal S; Lee, Daniel; Dhami, Hermandeep; Pro, Michael J; Waisbourd, Michael

    2016-09-01

    Glaucoma patients with markedly elevated intraocular pressure (IOP) are at risk for developing severe hypotony-related complications. The goal of this study was to compare the surgical outcomes of the Ahmed Glaucoma Valve (AGV) and the Baerveldt Glaucoma Implant (BGI) in this patient population. Patients with preoperative IOP≥30 mm Hg were included. Outcome measures were: (1) surgical failure (IOP>21 mm Hg or glaucoma surgery, or loss of light perception) and (2) surgical complications. A total of 75 patients were included: 37 in the AGV group and 38 in the BGI group. The mean±SD follow-up was 2.3±1.6 years for the AGV group and 2.4±1.7 years for the BGI group (P=0.643). Mean preoperative IOP was 38.7±6.5 mm Hg for the AGV group and 40.8±7.6 mm Hg for the BGI group. At the last follow-up, 10 (27.0%) patients failed in the AGV group compared with 6 (15.8%) patients in the BGI group (P=0.379). The BGI group had higher rate of flat or shallow anterior chamber (n=4, 10%) compared with the AGV group (n=0, 0%) (P=0.043). Failure rates of AGV and BGI in patients with IOP≥30 mm Hg were comparable. There were more early hypotony-related complications in the BGI group; however, none were vision threatening. Both glaucoma drainage implants were effective in treating patients with uncontrolled glaucoma in an emergency setting.

  2. Comparison of obesity, overweight and elevated blood pressure in children attending public and private primary schools in Benin City, Nigeria.

    Science.gov (United States)

    Sadoh, W E; Israel-Aina, Y T; Sadoh, A E; Uduebor, J E; Shaibu, M; Ogonor, E; Enugwuna, F C

    2017-07-01

    Overweight and obesity in children, and adolescents is on the rise globally. Affected children are prone to cardio-metabolic problems later in life, especially hypertension. The prevalence of obesity/overweight may differ depending on school type. Private schools are attended mostly by children of the affluent, while public schools are attended predominantly by those in the low and middle socio-economic classes. To compare the prevalence of overweight, obesity and elevated blood pressure (BP) in pupils attending public and private primary schools in an urban community in Nigeria. In this cross sectional study, the BMI and BP of pupils in public and private primary schools, recruited by multistage sampling method, were measured. Their nutritional status was categorized using their BMI percentiles. Analysis was by SPSS. A total of 1466 pupils were recruited, 814(55.5%) were in public schools and 722(49.2%) were males. The prevalence of overweight and obesity was higher in private schools 11.8% and 11.7% compared to public schools 3.3% and 0.9%. The mean systolic BP of pupils in public schools 96.8 ± 12.5 mmHg was higher than that in private schools 95.5 ± 10.2 mmHg, p = 0.032. Distribution of pupils with prehypertension and hypertension between private and public schools was not significantly different. The prevalence of overweight and obesity is higher in pupils attending private schools compared to those in public school. Urgent measures are needed to stem this tide through education, weight reduction and physical activity programs, especially in pupils attending private schools.

  3. Spaceflight-Induced Intracranial Hypertension: An Overview

    Science.gov (United States)

    Traver, William J.

    2011-01-01

    This slide presentation is an overview of the some of the known results of spaceflight induced intracranial hypertension. Historical information from Gemini 5, Apollo, and the space shuttle programs indicated that some vision impairment was reported and a comparison between these historical missions and present missions is included. Optic Disc Edema, Globe Flattening, Choroidal Folds, Hyperopic Shifts and Raised Intracranial Pressure has occurred in Astronauts During and After Long Duration Space Flight. Views illustrate the occurrence of Optic Disc Edema, Globe Flattening, and Choroidal Folds. There are views of the Arachnoid Granulations and Venous return, and the question of spinal or venous compliance issues is discussed. The question of increased blood flow and its relation to increased Cerebrospinal fluid (CSF) is raised. Most observed on-orbit papilledema does not progress, and this might be a function of plateau homeostasis for the higher level of intracranial pressure. There are seven cases of astronauts experiencing in flight and post flight symptoms, which are summarized and follow-up is reviewed along with a comparison of the treatment options. The question is "is there other involvement besides vision," and other Clinical implications are raised,

  4. Intracranial chondroma: a rare entity.

    Science.gov (United States)

    Maheshwari, Veena; Mehdi, Ghazala; Varshney, Manoranjan; Jain, Anshu; Vashishtha, Sonal; Gaur, Kavita; Srivastava, Vinod Kumar

    2011-05-12

    Intracranial chondroma is a rare benign cartilaginous tumour with an incidence of less than 1% of all primary intracranial tumours. The authors are reporting here a case of intracranial chondroma in a 40-year-old man who presented with 5-month history of headache and gradual diminution of vision. A tentative diagnosis of chondroma was made on imprint cytology which was confirmed on histopathological examination.

  5. Three cases of intracranial lipoma

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki; Kikuchi, Kenji; Yanagida, Noritaka; Fujii, Satoshi; Watanabe, Kazuo; Miyauchi, Takaharu

    1987-12-01

    Intracranial lipoma is an uncommon lesion that can be found in both symptomatic and asymptomatic patients. Because of CT (computerized tomography), the tumors can now be easily diagnosed in asymptomatic individuals. Three cases of intracranial lipoma in asymptomatic patients are presented, along with a review of the literature, and the value of CT, especially coronal section, in the diagnosis of intracranial lipomas and associated anomalies, such as the agenesis of corpus callosum, is discussed.

  6. The contemporary management of intracranial atherosclerotic disease.

    Science.gov (United States)

    Leng, Xinyi; Wong, Ka Sing; Leung, Thomas W

    2016-06-01

    Intracranial atherosclerotic disease is the most common cause of cerebral vasculopathy and an important stroke etiology worldwide, with a higher prevalence in Asian, Hispanic and African ethnicities. Symptomatic intracranial atherosclerotic disease portends a recurrent stroke risk as high as 18% at one year. The key to secondary prevention is an understanding of the underlying stroke mechanism and aggressive control of conventional cardiovascular risks. Contemporary treatment includes antiplatelet therapy, optimal glycemic and blood pressure control, statin therapy and lifestyle modifications. For patients with high-grade (70-99%) symptomatic steno-occlusion, short-term dual antiplatelet therapy with aspirin and clopidogrel followed by life-long single antiplatelet therapy may reduce the recurrent risk. Current evidence does not advocate percutaneous transluminal angioplasty and stenting as an initial treatment. External counterpulsation, encephaloduroarteriosynangiosis and remote limb ischemic preconditioning are treatments under investigation. Future studies should aim at predicting patients prone to recurrence despite of medical therapies and testing the efficacy of emerging therapies.

  7. Direct numerical simulations of temporally developing hydrocarbon shear flames at elevated pressure: effects of the equation of state and the unity Lewis number assumption

    Science.gov (United States)

    Korucu, Ayse; Miller, Richard

    2016-11-01

    Direct numerical simulations (DNS) of temporally developing shear flames are used to investigate both equation of state (EOS) and unity-Lewis (Le) number assumption effects in hydrocarbon flames at elevated pressure. A reduced Kerosene / Air mechanism including a semi-global soot formation/oxidation model is used to study soot formation/oxidation processes in a temporarlly developing hydrocarbon shear flame operating at both atmospheric and elevated pressures for the cubic Peng-Robinson real fluid EOS. Results are compared to simulations using the ideal gas law (IGL). The results show that while the unity-Le number assumption with the IGL EOS under-predicts the flame temperature for all pressures, with the real fluid EOS it under-predicts the flame temperature for 1 and 35 atm and over-predicts the rest. The soot mass fraction, Ys, is only under-predicted for the 1 atm flame for both IGL and real gas fluid EOS models. While Ys is over-predicted for elevated pressures with IGL EOS, for the real gas EOS Ys's predictions are similar to results using a non-unity Le model derived from non-equilibrium thermodynamics and real diffusivities. Adopting the unity Le assumption is shown to cause misprediction of Ys, the flame temperature, and the mass fractions of CO, H and OH.

  8. Spontaneous Cerebrospinal Fluid Rhinorrhea as the Presenting Symptom of Idiopathic Intracranial Hypertension: A Case Series

    Directory of Open Access Journals (Sweden)

    Hossein Ghalaenovi

    2018-05-01

    Full Text Available Although rare, Cerebrospinal Fluid (CSF Leakage can result in deadly complications such as meningitis and brain abscess. Previously, primary spontaneous CSF leakage was referred to leakages without any detectable causes. However, it has been found recently that it may be related to abnormal increased intracranial pressure (ICP. Here, we reported demographic, clinical, and therapeutic features in addition to the outcomes of five patients with Idiopathic Intracranial Hypertension (IIH presented with spontaneous CSF leakage as the initial symptom. Four of our patients were female. The mean age was 38 years old. Rhinorrhea was the first manifestation of the CSF leakage in our patients. Ethmoidal cells were the most common site of leakage. The mean opening pressures (OP was 31.3 cmH2O. The computed tomography (CT scan and magnetic resonance imaging (MRI of the brain was normal in all patients except one patient showing fullness in left ethmoidal cells. In all of the patients, cerebral CT cisternography was diagnostic to detect the site of leakage. CSF leak in two patients resolved with medical therapy but CSF diversion procedure was mandatory in other three patients. CSF leakage resolved in all of them. CSF leakage can be the first and only presenting symptom of abnormal increased ICP. The key point in patient treatment is controlling the elevated ICP, even though some patients may need to CSF diversion procedure eventually.

  9. Factors associated with elevated blood pressure or hypertension in Afro-Caribbean youth: a cross-sectional study.

    Science.gov (United States)

    Ferguson, Trevor S; Younger-Coleman, Novie O M; Tulloch-Reid, Marshall K; Bennett, Nadia R; Rousseau, Amanda E; Knight-Madden, Jennifer M; Samms-Vaughan, Maureen E; Ashley, Deanna E; Wilks, Rainford J

    2018-01-01

    Although several studies have identified risk factors for high blood pressure (BP), data from Afro-Caribbean populations are limited. Additionally, less is known about how putative risk factors operate in young adults and how social factors influence the risk of high BP. In this study, we estimated the relative risk for elevated BP or hypertension (EBP/HTN), defined as BP ≥ 120/80 mmHg, among young adults with putative cardiovascular disease (CVD) risk factors in Jamaica and evaluated whether relative risks differed by sex. Data from 898 young adults, 18-20 years old, were analysed. BP was measured with a mercury sphygmomanometer after participants had been seated for 5 min. Anthropometric measurements were obtained, and glucose, lipids and insulin measured from a fasting venous blood sample. Data on socioeconomic status (SES) were obtained via questionnaire. CVD risk factor status was defined using standard cut-points or the upper quintile of the distribution where the numbers meeting standard cut-points were small. Relative risks were estimated using odds ratios (OR) from logistic regression models. Prevalence of EBP/HTN was 30% among males and 13% among females ( p  women, high triglycerides (OR 1.98, CI [1.03-3.81], p  = 0.040) and high HOMA-IR (OR 2.07, CI [1.03-4.12], p  = 0.039) were positively associated with EBP/HTN. Lower SES was also associated with higher odds for EBP/HTN (OR 4.63, CI [1.31-16.4], p  = 0.017, for moderate vs. high household possessions; OR 2.61, CI [0.70-9.77], p  = 0.154 for low vs. high household possessions). Alcohol consumption was associated with lower odds of EBP/HTN among females only; OR 0.41 (CI [0.18-0.90], p  = 0.026) for drinking women lower SES was positively associated with EBP/HTN, while moderate alcohol consumption was associated lower odds of EBP/HTN.

  10. Elevated central venous pressure is associated with impairment of microcirculatory blood flow in sepsis: a hypothesis generating post hoc analysis

    NARCIS (Netherlands)

    Vellinga, Namkje A. R.; Ince, C.; Boerma, E. C.

    2013-01-01

    Microcirculatory driving pressure is defined as the difference between post-arteriolar and venular pressure. In previous research, an absence of correlation between mean arterial blood pressure (MAP) and microcirculatory perfusion has been observed. However, the microcirculation may be considered as

  11. Primary intracranial malignant lymphoma

    International Nuclear Information System (INIS)

    Matsumoto, Mikiro; Ohtsuka, Takatsugu; Kuroki, Takao; Shibata, Iekado; Terao, Hideo; Kudo, Motoshige

    1988-01-01

    Nine cases of primary intracranial malignant lymphoma, which accounts for 3.3 % of all intracranial tumors seen in the authors' institution, were studied in terms of diagnostic computed tomographic (CT) features, the tumors' histologic appearance, treatment, post-treatment blood immunologic and cerebrospinal fluid (CSF) characteristics, and outcome. The patients were seven males and two females aged 42 to 67 years. Their chief signs and symptoms on admission were intracranial hypertension, focal signs, and disturbance of consciousness. CT, which proved the most useful preoperative diagnostic technique, demonstrated multiple lesions in seven cases and, in all cases, regions of isodensity or slight high density that were enhanced by contrast medium. According to the patterns of enhancement, the tumors were classed as diffuse (three cases) or nodular (six cases). The former is considered typical of malignant lymphoma, whereas the latter type was sometimes indistinguishable from metastatic tumor and meningioma. At surgery, one patient underwent radical tumor excision, two partial removal, and six biopsy only. Histologic examination revealed one tumor to be of the diffuse small cell type, three of the medium cell type, and five of the large cell type (Lymphoma Study Group classification). Of seven tumors in which lymphocytes were examined by peroxidase-antiperoxidase staining, four were of the B cell type. Postoperatively, whole brain irradiation with 29 to 46 Gy was followed by local irradiation with 15 to 50 Gy. If the tumor persisted, one of three chemotherapies was administered. In one case, methotrexate was given intrathecally. Seven patients were divided into two groups: long remission (three) and recurrence (four). These two groups were compared in terms of serum immunoglobulin levels, T and B cell ratios, CSF characteristics, CT features, tumor cell type, and treatment. No clear differences were found. (author)

  12. Intracranial Hemorrhage in Pregnancy

    Directory of Open Access Journals (Sweden)

    Afshan B. Hameed

    2012-11-01

    Full Text Available A pregnant woman with a mechanical prosthetic mitral valve was anticoagulated with low-molecular-weight heparin in the first trimester followed by warfarin until 36 weeks' gestation. She was then switched to intravenous unfractionated heparin infusion to allow for regional anesthesia in anticipation of vaginal delivery. She developed severe headache on hospital day 2 that was refractory to pain medications. Cranial imaging demonstrated a large subdural hematoma with midline shift. She delivered a healthy baby girl by cesarean section. Eventually, symptoms and intracranial abnormalities resolved over time. In conclusion, subdural hematoma is a relatively rare complication that requires multidisciplinary management plan.

  13. Association between Selective Beta-adrenergic Drugs and Blood Pressure Elevation: Data Mining of the Japanese Adverse Drug Event Report (JADER) Database.

    Science.gov (United States)

    Ohyama, Katsuhiro; Inoue, Michiko

    2016-01-01

    Selective beta-adrenergic drugs are used clinically to treat various diseases. Because of imperfect receptor selectivity, beta-adrenergic drugs cause some adverse drug events by stimulating other adrenergic receptors. To examine the association between selective beta-adrenergic drugs and blood pressure elevation, we reviewed the Japanese Adverse Drug Event Reports (JADERs) submitted to the Japan Pharmaceuticals and Medical Devices Agency. We used the Medical Dictionary for Regulatory Activities (MedDRA) Preferred Terms extracted from Standardized MedDRA queries for hypertension to identify events related to blood pressure elevation. Spontaneous adverse event reports from April 2004 through May 2015 in JADERs, a data mining algorithm, and the reporting odds ratio (ROR) were used for quantitative signal detection, and assessed by the case/non-case method. Safety signals are considered significant if the ROR estimates and lower bound of the 95% confidence interval (CI) exceed 1. A total of 2021 reports were included in this study. Among the nine drugs examined, significant signals were found, based on the 95%CI for salbutamol (ROR: 9.94, 95%CI: 3.09-31.93) and mirabegron (ROR: 7.52, 95%CI: 4.89-11.55). The results of this study indicate that some selective beta-adrenergic drugs are associated with blood pressure elevation. Considering the frequency of their indications, attention should be paid to their use in elderly patients to avoid adverse events.

  14. Idiopathic intracranial hypertension in pediatric patients

    Directory of Open Access Journals (Sweden)

    Nada Jirásková

    2008-11-01

    Full Text Available Nada Jirásková, Pavel RozsívalDepartment of Ophthalmology, University Hospital, Hradec Králové, Czech RepublicPurpose: To evaluate retrospectively the features, treatment, and outcome of idiopathic intracranial hypertension (IIH in children.Methods: Nine patients, 15 years and younger, diagnosed with IIH. Inclusion criteria were papilledema, normal brain computer tomography or magnetic resonance imaging, cerebrospinal fluid pressure greater than 250 mm H2O, normal cerebrospinal fluid content, and a nonfocal neurologic examination except for sixth nerve palsy.Results: Of the nine patients, eight were girls. Five girls were overweight and one boy was obese. The most common presenting symptom was headache (5 patients. Diplopia or strabismus did not occur in our group. Visual field abnormalities were present in all eyes, and severe visual loss resulting in light perception vision occurred in both eyes of one patient. Eight patients were treated medically with acetazolamide alone, and one girl needed a combination of acetazolamide and corticosteroids. This girl also required optic nerve sheath decompression surgery. Resolution of papilledema and recovery of visual function occurred in all patients.Conclusions: Idiopathic intracranial hypertension in prepubertal children is rather uncommon. Prompt diagnosis and management are important to prevent permanent visual loss.Keywords: idiopathic intracranial hypertension, pediatric, treatment

  15. Spontaneous intracranial hypotension

    International Nuclear Information System (INIS)

    Cardwell, C.; Cox, I.; Baldey, A.

    2002-01-01

    Full text: A 49-year old female presented with severe postural headache with no history of trauma. A Computed Tomography (CT) study of the brain demonstrated abnormal meningeal enhancement raising the possibility of leptomeningeal metastases. The patient was then referred to Magnetic Resonance Imaging (MRI) which demonstrated diffuse smooth dural enhancement with ancillary findings characteristic of spontaneous intracranial hypotension. The patient was then referred to Nuclear Medicine to confirm the diagnosis and localise the presumed leak 400MBq of 99mTc DTPA was injected via lumbar puncture into the L3-L4 subarachnoid space Posterior images of the spine were taken with a GE XRT single head gamma camera at 1 and 4 hours post administration of radionuclide. Images demonstrated abnormal early arrival of radionuclide in the kidneys and bladder at 1 hour and abnormal leak of tracer was demonstrate at the level of the first thoracic vertebra on the right side at 4 hours. This confirmed CSF leak at this level. Consequently the patient underwent a blood patch and her symptoms resolved. Spontaneous Intracranial Hypotension is a syndrome often unrecognised presenting with symptoms including severe postural headache neck stiffness nausea vomiting tinnitus and vertigo. The diagnosis is frequently suspected from findings on MRI, but Nuclear Medicine CSF imaging provides a readily available and cost effective method for confirming the diagnosis, and for making the diagnosis in patients who are unsuitable for or do not have access to MRI. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  16. Spontaneous intracranial hypotension

    Energy Technology Data Exchange (ETDEWEB)

    Cardwell, C; Cox, I; Baldey, A [St. F.X. Cabrini Hospital, VIC (Australia). Departments of Nuclear Medicine and Magnetic Resonance Imaging

    2002-07-01

    Full text: A 49-year old female presented with severe postural headache with no history of trauma. A Computed Tomography (CT) study of the brain demonstrated abnormal meningeal enhancement raising the possibility of leptomeningeal metastases. The patient was then referred to Magnetic Resonance Imaging (MRI) which demonstrated diffuse smooth dural enhancement with ancillary findings characteristic of spontaneous intracranial hypotension. The patient was then referred to Nuclear Medicine to confirm the diagnosis and localise the presumed leak 400MBq of 99mTc DTPA was injected via lumbar puncture into the L3-L4 subarachnoid space Posterior images of the spine were taken with a GE XRT single head gamma camera at 1 and 4 hours post administration of radionuclide. Images demonstrated abnormal early arrival of radionuclide in the kidneys and bladder at 1 hour and abnormal leak of tracer was demonstrate at the level of the first thoracic vertebra on the right side at 4 hours. This confirmed CSF leak at this level. Consequently the patient underwent a blood patch and her symptoms resolved. Spontaneous Intracranial Hypotension is a syndrome often unrecognised presenting with symptoms including severe postural headache neck stiffness nausea vomiting tinnitus and vertigo. The diagnosis is frequently suspected from findings on MRI, but Nuclear Medicine CSF imaging provides a readily available and cost effective method for confirming the diagnosis, and for making the diagnosis in patients who are unsuitable for or do not have access to MRI. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc.

  17. Blood Pressure Elevation Associated with Topical Prostaglandin F2α Analogs: An Analysis of the Different Spontaneous Adverse Event Report Databases.

    Science.gov (United States)

    Ohyama, Katsuhiro; Kawakami, Haruna; Inoue, Michiko

    2017-01-01

    Topical prostaglandin F2α (PGF2α) analogs are widely used as the first line of therapy for glaucoma. Systemic PGF2α is suggested to increase blood pressure. Some ophthalmic formulations with β-receptor blocking or α-receptor stimulating actions are reported to cause systemic adverse events such as a decrease in heart rate and blood pressure. The objective of this study was to evaluate the association between topical PGF2α analogs and blood pressure elevation. We analyzed the reports obtained from the Food and Drug Administration Adverse Event Reporting System (FAERS) database from the first quarter of 2004 until the end of 2015 and the Japanese Adverse Drug Event Report (JADER) database from April 2004 to January 2016 for signal detection using reporting odds ratio (ROR), a method of disproportionality analyses. Signals are considered significant if the ROR estimates and lower bound of the 95% confidence interval (CI) exceed 1. Preferred terms in the Medical Dictionary for Regulatory Activities were utilized to define blood pressure elevation. A total of 6156081 reports from the FAERS and 351226 reports from the JADER were analyzed. The significant RORs with 95% CI were calculated to be 1.82 (95% CI: 1.55-2.13) for bimatoprost, 1.69 (95% CI: 1.53-1.85) for latanoprost, and 2.17 (95% CI: 1.82-2.59) for travoprost from the FAERS. From the JADER, 5.01 (95% CI: 1.59-15.8) was calculated for bimatoprost and 8.02 (95% CI: 2.94-21.9) for tafluprost. The resulting data suggest the necessity for further clinical research on blood pressure elevation associated with topical PGF2α analogs and close monitoring.

  18. [The affect of Erigeron Breviscapus (Vant.) Hand-Mazz on axoplasmic transport of optic nerve in rats with experimentally elevated intraocular pressure].

    Science.gov (United States)

    Zhu, Y; Jiang, Y; Liu, Z; Luo, X; Wu, Z

    2000-07-01

    To investigate whether Erigeron Breviscapus (Vant.) Hand-Mazz (EBHM) can improve the optic nerve axoplasmic transport in rats with experimentally elevated intraocular pressure (IOP). Thirty healthy SD rats were used for the study, acute elevated IOP model in the right eye was built, then they were divided into three groups randomly: Group A (0 day group) included six rats for retinal ganglion cell (RGC) counting via left superior colliculus retrograde horse radish perokidase labeling; Group B, twelve rats divided into EBHM treatment group and control group (6 rats in each subgroup) for RGC counting via left superior colliculus retrograde labeling after twenty days, and Group C included twelve rats submitted the same treatment and procedure as group B after 40 days. After 0 day of acute elevated IOP, no labeled RGCs were observed. After twenty days of acute elevated IOP, in the control and EBHM subgroups the density of labeled RGCs were (423 +/- 220)/mm(2) and (749 +/- 294)/mm(2) respectively, the difference between two subgroups showed statistical significance (P < 0.01). After 40 days of acute elevated IOP, the density of RGCs in the control and EBHM subgroups in group C were (610 +/- 315)/mm(2) and (1,048 +/- 393)/mm(2) respectively, the difference between the two subgroups being statistically significant (P < 0.01). After 20 days and 40 days of acute elevation of IOP, the density of RGCs is obviously higher in EBHM group than that in the control group. It is revealed that EBHM can improve the optic nerve axoplasmic transportation blocked by acute elevation of IOP in rats.

  19. Intracranial solitary fibrous tumor: Imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Clarencon, Frederic, E-mail: fredclare5@msn.com [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Bonneville, Fabrice [Department of Neuroradiology, Hopital Rangueil, Toulouse University Hospital, 31000 Toulouse (France); Rousseau, Audrey [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Galanaud, Damien [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Kujas, Michele [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Naggara, Olivier [Department of Neuroradiology, St Anne Hospital, 75014 Paris (France); Cornu, Philippe [Department of Neurosurgery, Pitie-Salpetriere Hospital (France); Chiras, Jacques [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France)

    2011-11-15

    Objective: To study the neuroimaging features of intracranial solitary fibrous tumors (ISFTs). Materials and methods: Retrospective study of neuroimaging features of 9 consecutive histopathologically proven ISFT cases. Location, size, shape, density, signal intensity and gadolinium uptake were studied at CT and MRI. Data collected from diffusion-weighted imaging (DWI) (3 patients), perfusion imaging and MR spectroscopy (2 patients), and DSA (4 patients) were also analyzed. Results: The tumors most frequently arose from the intracranial meninges (7/9), while the other lesions were intraventricular. Tumor size ranged from 2.5 to 10 cm (mean = 6.6 cm). They presented multilobular shape in 6/9 patients. Most ISFTs were heterogeneous (7/9) with areas of low T2 signal intensity that strongly enhanced after gadolinium administration (6/8). Erosion of the skull was present in about half of the cases (4/9). Components with decreased apparent diffusion coefficient were seen in 2/3 ISFTs on DWI. Spectroscopy revealed elevated peaks of choline and myo-inositol. MR perfusion showed features of hyperperfusion. Conclusion: ISFT should be considered in cases of extra-axial, supratentorial, heterogeneous, hypervascular tumor. Areas of low T2 signal intensity that strongly enhance after gadolinium injection are suggestive of this diagnosis. Restricted diffusion and elevated peak of myo-inositol may be additional valuable features.

  20. Factors associated with elevated blood pressure or hypertension in Afro-Caribbean youth: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Trevor S. Ferguson

    2018-02-01

    Full Text Available Background Although several studies have identified risk factors for high blood pressure (BP, data from Afro-Caribbean populations are limited. Additionally, less is known about how putative risk factors operate in young adults and how social factors influence the risk of high BP. In this study, we estimated the relative risk for elevated BP or hypertension (EBP/HTN, defined as BP ≥ 120/80 mmHg, among young adults with putative cardiovascular disease (CVD risk factors in Jamaica and evaluated whether relative risks differed by sex. Methods Data from 898 young adults, 18–20 years old, were analysed. BP was measured with a mercury sphygmomanometer after participants had been seated for 5 min. Anthropometric measurements were obtained, and glucose, lipids and insulin measured from a fasting venous blood sample. Data on socioeconomic status (SES were obtained via questionnaire. CVD risk factor status was defined using standard cut-points or the upper quintile of the distribution where the numbers meeting standard cut-points were small. Relative risks were estimated using odds ratios (OR from logistic regression models. Results Prevalence of EBP/HTN was 30% among males and 13% among females (p < 0.001 for sex difference. There was evidence for sex interaction in the relationship between EBP/HTN and some of risk factors (obesity and household possessions, therefore we report sex-specific analyses. In multivariable logistic regression models, factors independently associated with EBP/HTN among men were obesity (OR 8.48, 95% CI [2.64–27.2], p < 0.001, and high glucose (OR 2.01, CI [1.20–3.37], p = 0.008, while high HOMA-IR did not achieve statistical significance (OR 2.08, CI [0.94–4.58], p = 0.069. In similar models for women, high triglycerides (OR 1.98, CI [1.03–3.81], p = 0.040 and high HOMA-IR (OR 2.07, CI [1.03–4.12], p = 0.039 were positively associated with EBP/HTN. Lower SES was also associated with higher odds for

  1. Basic mechanisms in intracranial large-artery atherosclerosis: advances and challenges.

    Science.gov (United States)

    Arenillas, Juan F; Alvarez-Sabín, José

    2005-01-01

    Intracranial large-artery atherosclerosis is a major cause of ischemic stroke worldwide. Patients affected by this disease are at a high risk of suffering recurrent ischemic events despite antithrombotic therapy. Progression and a greater extent of intracranial atherosclerosis imply a higher risk for recurrence. Studies performed by our group in patients with symptomatic intracranial large-artery atherosclerosis have shown that: (1) C-reactive protein predicts its progression and recurrence, suggesting that inflammation may play a deleterious role in this condition; (2) a high level of the anti-angiogenic endostatin is also associated with a progressive and recurrent intracranial atherosclerosis, which might support a beneficial role for angiogenesis in this group of patients; and (3) elevated lipoprotein(a) concentration and diabetes mellitus characterize those patients with a higher number of intracranial stenoses. 2005 S. Karger AG, Basel

  2. Rectification of pulsatile stress on soft tissues: a mechanism for normal-pressure hydrocephalus

    Science.gov (United States)

    Jalikop, Shreyas; Hilgenfeldt, Sascha

    2011-11-01

    Hydrocephalus is a pathological condition of the brain that occurs when cerebrospinal fluid (CSF) accumulates excessively in the brain cavities, resulting in compression of the brain parenchyma. Counter-intuitively, normal-pressure hydrocephalus (NPH) does not show elevated pressure differences across the compressed parenchyma. We investigate the effects of nonlinear tissue mechanics and periodic driving in this system. The latter is due to the cardiac cycle, which provides significant intracranial pressure and volume flow rate fluctuations. Nonlinear rectification of the periodic driving within a model of fluid flow in poroelastic material can lead to compression or expansion of the parenchyma, and this effect does not rely on changes in the mean intracranial pressure. The rectification effects can occur gradually over several days, in agreement with clinical studies of NPH.

  3. Elevating your elevator talk

    Science.gov (United States)

    An important and often overlooked item that every early career researcher needs to do is compose an elevator talk. The elevator talk, named because the talk should not last longer than an average elevator ride (30 to 60 seconds), is an effective method to present your research and yourself in a clea...

  4. Secondary Intracranial Hypotension: A Case Report

    Directory of Open Access Journals (Sweden)

    Pinar Gundogan Bozdag

    2014-04-01

    Full Text Available Intracranial hypotension is a clinical condition that characterized by postural (orthostatic headache and low pressure. It apperas with cerebrospinal fluid leak which occurs spontaneous or depending on the secondary attempts. 31 years old female patient which has diagnosis of acute appendicitis and underwent appendectomy under spinal anesthesia. postoperative 5.day she admitted with a postural headache, diplopia. Patient was treated with conservative methods after diagnosed with magnetic resonance imaging. We aim to asses an encountered complication after spinal anesthesia which widely applied for surgical procedures with imaging findings and literature.

  5. Modeling Cyclic Variation of Intracranial Pressure

    National Research Council Canada - National Science Library

    Daley, M

    2001-01-01

    ...) recording during mechanical ventilation are due to cyclic extravascular compressional modulation primarily of the cerebral venous bed, an established isovolumetric model of cerebrospinal fluid...

  6. The evaluation of cerebral hemodynamics in patients with intracranial tumors by stable xenon CT; The effect of glycerol administration on regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Shimoda, Masami; Kawamata, Fumio; Yamamoto, Masahiro; Ohsuga, Hitoshi; Hidaka, Mitsuru; Oda, Shinri; Shibuya, Naoki; Yamamoto, Isao; Sato, Osamu (Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine)

    1989-04-01

    In evaluating cerebral regional blood flow (rCBF), stable xenon-enhanced tomography (XeCT) study associated with simultaneous blood sampling was applied in 15 cases of intracranial neoplasms. The effect of intravenous glycerol infusion on rCBF was also investigated. The results indicated that intratumoral rCBF values were not only variable and unrelated to their histological types and grades, but also were not correlated with the vascularity of the lesion as demonstrated by angiography. When a tumor mass was enhanced after the injection of iodinated contrast media, it proved to be useful in distinguishing tumor mass and its associated edema that the rCBF of the peritumoral edematous region was predominantly low (10{plus minus}5 ml/100 g/min). The regional cerebral blood flow in remote areas, both ipsilateral and contralateral to the lesion, was low in value, and there was no statistical significance between affected and sound sides. Following glycerol administration, rCBF was increased in the whole intracranial region, but not inside of the neoplasm, particularly when the intracranial pressure (ICP) was increased. It was assumed that the elevated rCBF after glycerol administration was due to the increase in the cerebral perfusion pressure resulting from the ICP reduction, the hemodilution effect, cerebral vessel dilatation after metabolic acidosis, and/or mechanically rectified microcirculation after edema reduction. (author).

  7. Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure%Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure

    Institute of Scientific and Technical Information of China (English)

    王琳; 曹丰璞; 刘珊珊; 杨浩

    2011-01-01

    High-pressure vapor-liquid phase equilibrium data for carbon dioxide+ isopentanol were measured at tempera- tures of 313.2, 323.1, 333.5 and 343.4 K in the pressure range of 4.64 to 12.71 MPa in a variable-volume high-pressure visual cell. The experimental data were well correlated with Peng-Robinson equation of state (PR-EOS) together with van der Waals-2 two-parameter mixing rule, and the binary interaction parameters were obtained. Henry coefficients and partial molar volumes of CO2 at infinite dilution were estimated based on Krichevsky-Kasarnovsky equation, and Henry coefficients increase with increasing temperature, however, partial molar volumes of CO2 at infinite dilution are negative and the magnitudes decrease with temperature.

  8. Species composition, elevation, and former management type affect browsing pressure on forest regeneration in the Tatra National Park

    Directory of Open Access Journals (Sweden)

    Bodziarczyk Jan

    2017-06-01

    Full Text Available Effects of ungulate pressure on the development of young generation of trees is one of the most important issues in ecology and forestry. Ungulate pressure influence on the development of natural regeneration has been also reported from several national parks. Our study on the effects of ungulate browsing on the young generation of trees was conducted on more than 500 sample plots controlled during one growing season.

  9. Intracranial Hypertension: Medication and Surgery

    Science.gov (United States)

    ... fallen out of favor, unless there is a secondary inflammatory process caused by an underlying disease like ... have little effect on headaches caused by intracranial hypertension, they may temporarily affect the intensity of a ...

  10. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

    Science.gov (United States)

    Groot, S. P. C.; Surki, A. A.; de Vos, R. C. H.; Kodde, J.

    2012-01-01

    Background and Aims Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. Methods Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. Key Results The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Conclusions Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice. PMID:22967856

  11. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions.

    Science.gov (United States)

    Groot, S P C; Surki, A A; de Vos, R C H; Kodde, J

    2012-11-01

    Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. methods: Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice.

  12. Elevated hydrostatic pressures induce apoptosis and oxidative stress through mitochondrial membrane depolarization in PC12 neuronal cells: A cell culture model of glaucoma.

    Science.gov (United States)

    Tök, Levent; Nazıroğlu, Mustafa; Uğuz, Abdülhadi Cihangir; Tök, Ozlem

    2014-10-01

    Despite the importance of oxidative stress and apoptosis through mitochondrial depolarization in neurodegenerative diseases, their roles in etiology of glaucoma are poorly understood. We aimed to investigate whether oxidative stress and apoptosis formation are altered in rat pheochromocytoma-derived cell line-12 (PC12) neuronal cell cultures exposed to elevated different hydrostatic pressures as a cell culture model of glaucoma. Cultured PC12 cells were subjected to 0, 15 and 70 mmHg hydrostatic pressure for 1 and 24 h. Then, the following values were analyzed: (a) cell viability; (b) lipid peroxidation and intracellular reactive oxygen species production; (c) mitochondrial membrane depolarization; (d) cell apoptosis; (e) caspase-3 and caspase-9 activities; (f) reduced glutathione (GSH) and glutathione peroxidase (GSH-Px). The hydrostatic pressures (15 and 70 mmHg) increased oxidative cell damage through a decrease of GSH and GSH-Px values, and increasing mitochondrial membrane potential. Additionally, 70 mmHg hydrostatic pressure for 24 h indicated highest apoptotic effects, as demonstrated by plate reader analyses of apoptosis, caspase-3 and -9 values. The present data indicated oxidative stress, apoptosis and mitochondrial changes in PC12 cell line during different hydrostatic pressure as a cell culture model of glaucoma. This findings support the view that mitochondrial oxidative injury contributes early to glaucomatous optic neuropathy.

  13. Intracranial hypotension - a look beyond “bilateral subdural hematomas”

    International Nuclear Information System (INIS)

    Penev, B.

    2015-01-01

    Full text: The intracranial hypotension (ICH) is a disorder due to spontaneous or iatrogenic CSF leak and a low intracranial pressure. The clinical presentation is characterized by drug resistant orthostatic headache, nausea, vomiting, dizziness, neck pain and etc. The intracranial hypotension is defined as a benign disorder and the treatment is predominantly conservative. Due to this fact it is very important to differentiate this entity from subdural hematomas and hygromas which are treated surgically. Magnetic resonance imaging has revolutionized the diagnosis of ICH. Nowadays there are a lot of clinical and imaging features of this disorder. Regardless of clinical varieties and atypical forms, MRI gives enough information for the correct or probable diagnosis in the vast majority of the cases. The initial imaging resemblance with posttraumatic subdural hematomas and hygromas can result in giving the wrong diagnosis and therefore performing unneeded surgical interventions. the aim of this presentation is to discuss the contemporary criteria, algorithm and imaging features of ICH