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Sample records for cerebral autoregulation dynamics

  1. Dynamic Cerebral Autoregulation after Cardiopulmonary Bypass

    DEFF Research Database (Denmark)

    Christiansen, Claus Behrend; Berg, Ronan M G; Plovsing, Ronni;

    2016-01-01

    Background Cerebral hemodynamic disturbances in the peri- or postoperative period may contribute to postoperative cognitive dysfunction (POCD) in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). We therefore examined dynamic cerebral autoregulation (d...

  2. Dynamic cerebral autoregulation measured with coherent hemodynamics spectroscopy (CHS)

    Science.gov (United States)

    Kainerstorfer, Jana M.; Sassaroli, Angelo; Tgavalekos, Kristen T.; Fantini, Sergio

    2015-03-01

    Coherent Hemodynamics Spectroscopy (CHS) is a novel technique for non-invasive measurements of local microcirculation quantities such as the capillary blood transit times and dynamic autoregulation. The basis of CHS is to measure, for instance with near-infrared spectroscopy (NIRS), peripheral coherent hemodynamic changes that are induced by controlled perturbations in the systemic mean arterial pressure (MAP). In this study, the MAP perturbation was induced by the fast release of two pneumatic cuffs placed around the subject's thighs after they were kept inflated (at 200 mmHg) for two minutes. The resulting transient changes in cerebral oxy- (O) and deoxy- (D) hemoglobin concentrations measured with NIRS on the prefrontal cortex are then described by a novel hemodynamic model, from which quantifiable parameters such as the capillary blood transit time and a cutoff frequency for cerebral autoregulation are obtained. We present results on eleven healthy volunteers in a protocol involving measurements during normal breathing and during hyperventilation, which is known to cause a hypocapnia-induced increase in cerebral autoregulation. The measured capillary transit time was unaffected by hyperventilation (normal breathing: 1.1±0.1 s; hyperventilation: 1.1±0.1 s), whereas the cutoff frequency of autoregulation, which increases for higher autoregulation efficiency, was indeed found to be significantly greater during hyperventilation (normal breathing: 0.017±0.002 Hz; hyperventilation: 0.034±0.005 Hz). These results provide a validation of local cerebral autoregulation measurements with the new technique of CHS.

  3. Lipopolysaccharide infusion enhances dynamic cerebral autoregulation without affecting cerebral oxygen vasoreactivity in healthy volunteers

    DEFF Research Database (Denmark)

    Berg, Ronan Mg; Plovsing, Ronni R; Evans, Kevin A;

    2013-01-01

    Sepsis may be associated with disturbances in cerebral oxygen transport and cerebral haemodynamic function, thus rendering the brain particularly susceptible to hypoxia. The purpose of this study was to assess the impact of isocapnic hypoxia and hyperoxia on dynamic cerebral autoregulation in a h...

  4. Dynamic cerebral autoregulation changes during sub-maximal handgrip maneuver.

    Directory of Open Access Journals (Sweden)

    Ricardo C Nogueira

    Full Text Available PURPOSE: We investigated the effect of handgrip (HG maneuver on time-varying estimates of dynamic cerebral autoregulation (CA using the autoregressive moving average technique. METHODS: Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO₂ pressure (PETCO₂, and noninvasive arterial blood pressure (ABP were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP, resistance area-product (RAP, and time-varying autoregulation index (ARI were obtained. RESULTS: PETCO₂ did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005, which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. CONCLUSION: Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism.

  5. Dynamic Cerebral Autoregulation in Pregnancy and the Risk of Preeclampsia

    DEFF Research Database (Denmark)

    Janzarik, Wibke G; Ehlers, Elena; Ehmann, Renata;

    2014-01-01

    Preeclampsia may affect severely the cerebral circulation leading to impairment of cerebral autoregulation, edema, and ischemia. It is not known whether impaired autoregulation occurs before the clinical onset of preeclampsia, and whether this can predict the occurrence of preeclampsia. Seventy......) of respiratory-induced 0.1 Hz hemodynamic oscillations. Uterine artery ultrasound was performed to search for a notch sign as an early marker of general endothelial dysfunction. All women were followed up until 6 weeks after delivery for the occurrence of preeclampsia. The autoregulation parameter gain did...... not differ between pregnant and nonpregnant women. Phase was slightly but significantly higher in pregnant women, indicating better DCA. Women with a notch sign did not show altered DCA. A history of preeclampsia during a previous pregnancy was associated with lower phase in middle cerebral artery...

  6. Cerebral Autoregulation in Normal Pregnancy and Preeclampsia

    NARCIS (Netherlands)

    van Veen, Teelkien R.; Panerai, Ronney B.; Haeri, Sina; Griffioen, Annemiek C.; Zeeman, Gerda; Belfort, Michael A.

    2013-01-01

    OBJECTIVE: To test the hypothesis that preeclampsia is associated with impaired dynamic cerebral autoregulation. METHODS: In a prospective cohort analysis, cerebral blood flow velocity of the middle cerebral artery (determined by transcranial Doppler), blood pressure (determined by noninvasive arter

  7. Wavelet coherence analysis of dynamic cerebral autoregulation in neonatal hypoxic–ischemic encephalopathy

    Directory of Open Access Journals (Sweden)

    Fenghua Tian

    2016-01-01

    Full Text Available Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic–ischemic encephalopathy (HIE. These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP and cerebral tissue oxygenation saturation (SctO2 were continuously recorded. Wavelet coherence analysis, which is a time-frequency domain approach, was used to characterize the dynamic relationship between spontaneous oscillations in MAP and SctO2. Wavelet-based metrics of phase, coherence and gain were derived for quantitative evaluation of cerebral autoregulation. We found cerebral autoregulation in neonates with HIE was time-scale-dependent in nature. Specifically, the spontaneous changes in MAP and SctO2 had in-phase coherence at time scales of less than 80 min (<0.0002 Hz in frequency, whereas they showed anti-phase coherence at time scales of around 2.5 h (~0.0001 Hz in frequency. Both the in-phase and anti-phase coherence appeared to be related to worse clinical outcomes. These findings suggest the potential clinical use of wavelet coherence analysis to assess dynamic cerebral autoregulation in neonatal HIE during hypothermia.

  8. Wavelet coherence analysis of dynamic cerebral autoregulation in neonatal hypoxic-ischemic encephalopathy.

    Science.gov (United States)

    Tian, Fenghua; Tarumi, Takashi; Liu, Hanli; Zhang, Rong; Chalak, Lina

    2016-01-01

    Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic-ischemic encephalopathy (HIE). These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP) and cerebral tissue oxygenation saturation (SctO2) were continuously recorded. Wavelet coherence analysis, which is a time-frequency domain approach, was used to characterize the dynamic relationship between spontaneous oscillations in MAP and SctO2. Wavelet-based metrics of phase, coherence and gain were derived for quantitative evaluation of cerebral autoregulation. We found cerebral autoregulation in neonates with HIE was time-scale-dependent in nature. Specifically, the spontaneous changes in MAP and SctO2 had in-phase coherence at time scales of less than 80 min (hypothermia. PMID:26937380

  9. Bilateral severe carotid artery stenosis or occlusion : cerebral autoregulation dynamics and collateral flow patterns

    OpenAIRE

    Reinhard, Matthias; Müller, Thomas; Roth, Markus; Guschlbauer, Brigitte; Timmer, Jens; Hetzel, Andreas

    2003-01-01

    BackgroundBilateral severe obstruction of the internal carotid artery is a hemodynamically critical state. We aimed to (1) analyze dynamic cerebral autoregulation (DCA) in affected patients, and (2) to correlate DCA data with different collateral flow patterns.MethodsDCA was assessed noninvasively by transfer function analysis (phase shift) of respiratory-induced oscillations at 0.1 Hz of arterial blood pressure (Finapres method) and cerebral blood flow velocity (transcranial Doppler) in 30 p...

  10. Cerebral autoregulation dynamics in endurance-trained individuals

    DEFF Research Database (Denmark)

    Lind-Holst, Mikkel; Cotter, James D; Helge, Jørn W;

    2011-01-01

    of increase in the cerebrovascular conductance index (CVCi = MCA V(mean)/MAP) appeared later in the athletes (3.9 ± 0.4 vs. 2.7 ± 0.4s, P = 0.01). Spectral analysis revealed a normal MAP-to-MCA V(mean) phase in both groups but ~40% higher normalized MAP to MCA V(mean) low-frequency transfer function gain...... in untrained subjects and was associated with parallel changes in indexes of cerebral blood flow. Once initiated, the autoregulatory response was similar between the groups. A delayed onset of autoregulation with a larger normalized transfer gain conforms with a less effective dampening of MAP oscillations...... pressure (MAP) after 2.5 min of leg ischemia in endurance athletes and untrained subjects (maximal O(2) uptake: 69 ± 7 vs. 42 ± 5 ml O(2)·min(-1)·kg(-1); n = 9 for both, means ± SE). After cuff release when seated, endurance athletes had larger drops in MAP (94 ± 6 to 62 ± 5 mmHg, -39%, vs. 99 ± 5 to 73...

  11. Dynamic cerebral autoregulation during repeated squat-stand maneuvers.

    NARCIS (Netherlands)

    Claassen, J.A.H.R.; Levine, B.D.; Zhang, R.

    2009-01-01

    Transfer function analysis of spontaneous oscillations in blood pressure (BP) and cerebral blood flow (CBF) can quantify the dynamic relationship between BP and CBF. However, such oscillation amplitudes are often small and of questionable clinical significance, vary substantially, and cannot be cont

  12. Dynamic cerebral autoregulation to induced blood pressure changes in human experimental and clinical sepsis

    DEFF Research Database (Denmark)

    Berg, Ronan M G; Plovsing, Ronni R; Bailey, Damian M;

    2016-01-01

    Previous studies have demonstrated that dynamic cerebral autoregulation to spontaneous fluctuations in blood pressure is enhanced following lipopolysaccharide (LPS) infusion, a human experimental model of early sepsis, whereas by contrast it is impaired in patients with severe sepsis or septic......R). This was performed before and after LPS infusion in healthy volunteers, and within 72 h following clinical diagnosis of sepsis in patients. In healthy volunteers, thigh-cuff deflation caused a MAP reduction of 16 (13-20) % at baseline and 18 (16-20) % after LPS, while the MAP reduction was 12 (11-13) % in patients......(-1) ; P = 0·91 versus baseline; P = 0·14 versus LPS]. While our findings support the concept that dynamic cerebral autoregulation is enhanced during the very early stages of sepsis, they remain inconclusive with regard to more advanced stages of disease, because thigh-cuff deflation failed to induce...

  13. Cardiac baroreflex function and dynamic cerebral autoregulation in elderly Masters athletes

    NARCIS (Netherlands)

    Aengevaeren, V.L.; Claassen, J.A.H.R.; Levine, B.D.; Zhang, R.

    2013-01-01

    Cerebral blood flow (CBF) is stably maintained through the combined effects of blood pressure (BP) regulation and cerebral autoregulation. Previous studies suggest that aerobic exercise training improves cardiac baroreflex function and beneficially affects BP regulation, but may negatively affect ce

  14. Cerebral autoregulation dynamics in endurance-trained individuals

    NARCIS (Netherlands)

    M. Lind-Holst; J.D. Cotter; J.W. Helge; R. Boushel; H. Augustesen; J.J. van Lieshout; F.C. Pott

    2011-01-01

    Aerobic fitness may be associated with reduced orthostatic tolerance. To investigate whether trained individuals have less effective regulation of cerebral vascular resistance, we studied the middle cerebral artery (MCA) mean blood velocity (V(mean)) response to a sudden drop in mean arterial pressu

  15. Ventricular Volume Load Reveals the Mechanoelastic Impact of Communicating Hydrocephalus on Dynamic Cerebral Autoregulation.

    Directory of Open Access Journals (Sweden)

    Christina Haubrich

    Full Text Available Several studies have shown that the progression of communicating hydrocephalus is associated with diminished cerebral perfusion and microangiopathy. If communicating hydrocephalus similarly alters the cerebrospinal fluid circulation and cerebral blood flow, both may be related to intracranial mechanoelastic properties as, for instance, the volume pressure compliance. Twenty-three shunted patients with communicating hydrocephalus underwent intraventricular constant-flow infusion with Hartmann's solution. The monitoring included transcranial Doppler (TCD flow velocities (FV in the middle (MCA and posterior cerebral arteries (PCA, intracranial pressure (ICP, and systemic arterial blood pressure (ABP. The analysis covered cerebral perfusion pressure (CPP, the index of pressure-volume compensatory reserve (RAP, and phase shift angles between Mayer waves (3 to 9 cpm in ABP and MCA-FV or PCA-FV. Due to intraventricular infusion, the pressure-volume reserve was exhausted (RAP 0.84+/-0.1 and ICP was increased from baseline 11.5+/-5.6 to plateau levels of 20.7+/-6.4 mmHg. The ratio dRAP/dICP distinguished patients with large 0.1+/-0.01, medium 0.05+/-0.02, and small 0.02+/-0.01 intracranial volume compliances. Both M wave phase shift angles (r = 0.64; p<0.01 and CPP (r = 0.36; p<0.05 displayed a gradual decline with decreasing dRAP/dICP gradients. This study showed that in communicating hydrocephalus, CPP and dynamic cerebral autoregulation in particular, depend on the volume-pressure compliance. The results suggested that the alteration of mechanoelastic characteristics contributes to a reduced cerebral perfusion and a loss of autonomy of cerebral blood flow regulation. Results warrant a prospective TCD follow-up to verify whether the alteration of dynamic cerebral autoregulation may indicate a progression of communicating hydrocephalus.

  16. Dynamic cerebral autoregulation: different signal processing methods without influence on results and reproducibility.

    Science.gov (United States)

    Gommer, Erik D; Shijaku, Eri; Mess, Werner H; Reulen, Jos P H

    2010-12-01

    Cerebral autoregulation controls cerebral blood flow under changing cerebral perfusion pressure. Standards for measurement and analysis of dynamic cerebral autoregulation (dCA) are lacking. In this study, dCA reproducibility, quantified by intraclass correlation coefficient, is evaluated for different methodological approaches of transfer function analysis (TFA) and compared with multimodal pressure flow analysis (MMPF). dCA parameters were determined in 19 healthy volunteers during three 15-min lasting epochs of spontaneous breathing. Every spontaneous breathing epoch was followed by 5 min of paced breathing at 6 cycles/min. These six measurements were performed in both a morning and an afternoon session. Analysis compared raw data pre-processing by mean subtraction versus smoothness priors detrending. The estimation of spectral density was either performed by averaging of subsequent time windows or by smoothing the spectrum of the whole recording. No significant influence of pre-processing and spectral estimation on dCA parameters was found. Therefore, there seems to be no need to prescribe a specific signal-processing regime. Poor reproducibility of gain and phase was found for TFA as well as for MMPF. Based on reproducibility, no preference can be made for morning versus afternoon measurements, neither for spontaneous versus paced breathing. Finally, reproducibility results are not in favour of TFA or MMPF.

  17. Effects of cerebral ischemia on human neurovascular coupling, CO2 reactivity, and dynamic cerebral autoregulation.

    Science.gov (United States)

    Salinet, Angela S M; Robinson, Thompson G; Panerai, Ronney B

    2015-01-15

    Cerebral blood flow (CBF) regulation can be impaired in acute ischemic stroke but the combined effects of dynamic cerebral autoregulation (CA), CO2 cerebrovascular reactivity (CVR), and neurovascular coupling (NVC), obtained from simultaneous measurements, have not been described. CBF velocity in the middle cerebral artery (MCA) (CBFv, transcranial Doppler), blood pressure (BP, Finometer), and end-tidal Pco2 (PetCO2 , infrared capnography) were recorded during a 1-min passive movement of the arm in 27 healthy controls [mean age (SD) 61.4 (6.0) yr] and 27 acute stroke patients [age 63 (11.7) yr]. A multivariate autoregressive-moving average model was used to separate the contributions of BP, arterial Pco2 (PaCO2 ), and the neural activation to the CBFv responses. CBFv step responses for the BP, CO2, and stimulus inputs were also obtained. The contribution of the stimulus to the CBFv response was highly significant for the difference between the affected side [area under the curve (AUC) 104.5 (4.5)%] and controls [AUC 106.9 (4.3)%; P = 0.008]. CBFv step responses to CO2 [affected hemisphere 0.39 (0.7), unaffected 0.55 (0.8), controls 1.39 (0.9)%/mmHg; P = 0.01, affected vs. controls; P = 0.025, unaffected vs. controls] and motor stimulus inputs [affected hemisphere 0.20 (0.1), unaffected 0.22 (0.2), controls 0.37 (0.2) arbitrary units; P = 0.009, affected vs. controls; P = 0.02, unaffected vs. controls] were reduced in the stroke group compared with controls. The CBFv step responses to the BP input at baseline and during the paradigm were not different between groups (P = 0.07), but PetCO2 was lower in the stroke group (P < 0.05). These results provide new insights into the interaction of CA, CVR, and NVC in both health and disease states. PMID:25593216

  18. Endotoxemia reduces cerebral perfusion but enhances dynamic cerebrovascular autoregulation at reduced arterial carbon dioxide tension*

    DEFF Research Database (Denmark)

    Brassard, Patrice; Kim, Yu-Sok; van Lieshout, Johannes;

    2012-01-01

    . INTERVENTIONS:: Systemic hemodynamics, middle cerebral artery mean flow velocity, and dynamic cerebral autoregulation evaluated by transfer function analysis in the very low (0.15 Hz) frequency ranges were monitored in these volunteers before and after an endotoxin bolus (2 ng/kg; Escherichia coli...... flow velocity (37 ± 9 cm·sec vs. 47 ± 10 cm·sec; p velocity variability (1.0 ± 1.0 [cm·sec] Hz vs. 2.8 ± 1.5 [cm·sec] Hz; p ...·sec.mm Hg vs. 0.74 ± 0.17 cm·sec.mm Hg; p velocity phase difference (p

  19. Continuous estimates of dynamic cerebral autoregulation during transient hypocapnia and hypercapnia.

    Science.gov (United States)

    Dineen, N E; Brodie, F G; Robinson, T G; Panerai, R B

    2010-03-01

    Dynamic cerebral autoregulation (CA) is the transient response of cerebral blood flow (CBF) to rapid blood pressure changes: it improves in hypocapnia and becomes impaired during hypercapnia. Batch-processing techniques have mostly been used to measure CA, providing a single estimate for an entire recording. A new approach to increase the temporal resolution of dynamic CA parameters was applied to transient hypercapnia and hypocapnia to describe the time-varying properties of dynamic CA during these conditions. Thirty healthy subjects (mean +/- SD: 25 +/- 6 yr, 9 men) were recruited. CBF velocity was recorded in both middle cerebral arteries (MCAs) with transcranial Doppler ultrasound. Arterial blood pressure (Finapres), end-tidal CO(2) (ET(CO(2)); infrared capnograph), and a three-lead ECG were also measured at rest and during repeated breath hold and hyperventilation. A moving window autoregressive moving average model provided continuous values of the dynamic CA index [autoregulation index (ARI)] and unconstrained gain. Breath hold led to significant increase in ET(CO(2)) (+5.4 +/- 6.1 mmHg), with concomitant increase in CBF velocity in both MCAs. Continuous dynamic CA parameters showed highly significant changes (P < 0.001), with a temporal pattern reflecting a delayed dynamic response of CA to changes in arterial Pco(2) and a maximal reduction in ARI of -5.1 +/- 2.4 and -5.1 +/- 2.3 for the right and left MCA, respectively. Hyperventilation led to a marked decrease in ET(CO(2)) (-7.2 +/- 4.1 mmHg, P < 0.001). Unexpectedly, CA efficiency dropped significantly with the inception of the metronome-controlled hyperventilation, but, after approximately 30 s, the ARI increased gradually to show a maximum change of 5.7 +/- 2.9 and 5.3 +/- 3.0 for the right and left MCA, respectively (P < 0.001). These results confirm the potential of continuous estimates of dynamic CA to improve our understanding of human cerebrovascular physiology and represent a promising new

  20. Continuous estimates of dynamic cerebral autoregulation: influence of non-invasive arterial blood pressure measurements

    International Nuclear Information System (INIS)

    Temporal variability of parameters which describe dynamic cerebral autoregulation (CA), usually quantified by the short-term relationship between arterial blood pressure (BP) and cerebral blood flow velocity (CBFV), could result from continuous adjustments in physiological regulatory mechanisms or could be the result of artefacts in methods of measurement, such as the use of non-invasive measurements of BP in the finger. In 27 subjects (61 ± 11 years old) undergoing coronary artery angioplasty, BP was continuously recorded at rest with the Finapres device and in the ascending aorta (Millar catheter, BPAO), together with bilateral transcranial Doppler ultrasound in the middle cerebral artery, surface ECG and transcutaneous CO2. Dynamic CA was expressed by the autoregulation index (ARI), ranging from 0 (absence of CA) to 9 (best CA). Time-varying, continuous estimates of ARI (ARI(t)) were obtained with an autoregressive moving-average (ARMA) model applied to a 60 s sliding data window. No significant differences were observed in the accuracy and precision of ARI(t) between estimates derived from the Finapres and BPAO. Highly significant correlations were obtained between ARI(t) estimates from the right and left middle cerebral artery (MCA) (Finapres r = 0.60 ± 0.20; BPAO r = 0.56 ± 0.22) and also between the ARI(t) estimates from the Finapres and BPAO (right MCA r = 0.70 ± 0.22; left MCA r = 0.74 ± 0.22). Surrogate data showed that ARI(t) was highly sensitive to the presence of noise in the CBFV signal, with both the bias and dispersion of estimates increasing for lower values of ARI(t). This effect could explain the sudden drops of ARI(t) to zero as reported previously. Simulated sudden changes in ARI(t) can be detected by the Finapres, but the bias and variability of estimates also increase for lower values of ARI. In summary, the Finapres does not distort time-varying estimates of dynamic CA obtained with a sliding window combined with an ARMA model, but

  1. Altered free radical metabolism in acute mountain sickness: implications for dynamic cerebral autoregulation and blood-brain barrier function

    DEFF Research Database (Denmark)

    Bailey, D M; Evans, K A; James, P E;

    2008-01-01

    We tested the hypothesis that dynamic cerebral autoregulation (CA) and blood-brain barrier (BBB) function would be compromised in acute mountain sickness (AMS) subsequent to a hypoxia-mediated alteration in systemic free radical metabolism. Eighteen male lowlanders were examined in normoxia (21% O...... developed clinical AMS (AMS+) and were more hypoxaemic relative to subjects without AMS (AMS-). A more marked increase in the venous concentration of the ascorbate radical (A(*-)), lipid hydroperoxides (LOOH) and increased susceptibility of low-density lipoprotein (LDL) to oxidation was observed during...

  2. Random perturbations of arterial blood pressure for the assessment of dynamic cerebral autoregulation

    International Nuclear Information System (INIS)

    The assessment of cerebral autoregulation (CA) relies mostly on methods that modulate arterial blood pressure (ABP). Despite advances, the gold standard of assessment remains elusive and clinical practicality is limited. We investigate a novel approach of assessing CA, consisting of the intermittent application of thigh cuffs using square wave sequences. Our aim was to increase ABP variability whilst minimizing volunteer discomfort, thus improving assessment acceptability. Two random square wave sequences and two maximum pressure settings (80 and 150 mmHg) were used, corresponding to four manoeuvres that were conducted in random order after a baseline recording. The intermittent application of thigh cuffs resulted in an amplitude dependent increase in ABP (p = 0.001) and cerebral blood flow velocity (CBFV) variability (p = 0.026) compared to baseline. No statistically significant differences in mean heart rate or heart rate variability were observed (p = 0.108 and p = 0.350, respectively), suggesting that no significant sympathetic response was elicited. No significant differences in the CBFV step response were observed, suggesting no distortion of autoregulatory parameters resulted from the use of thigh cuffs. We conclude that pseudorandom binary sequences are an effective and safe alternative for increasing ABP variability. This new approach shows great promise as a tool for the robust assessment of CA. (paper)

  3. Dynamic cerebral autoregulation and cerebrovascular reactivity: a comparative study in lacunar infarct patients

    International Nuclear Information System (INIS)

    The major purpose of this study was to simultaneously evaluate dCA before and shortly after cerebral vasodilatation evoked by infusion of acetazolamide (ACZ). It was questioned if and to what degree dCA was changed after ACZ infusion. Using 15 mg kg−1 ACZ infusion cerebrovascular reactivity (CVR) was assessed in 29 first ever lacunar stroke patients (19 M/10 F). During the CVR-test, the electrocardiogram, non-invasive finger arterial blood pressure (ABP) and middle cerebral artery blood flow velocity (CBFV) were recorded. DCA based on spontaneous blood pressure variations was evaluated in 24 subjects by linear transfer function analysis. Squared coherence, gain and phase angle in the frequency range of autoregulation (0.04–0.16 Hz) were compared before and after ACZ infusion. After ACZ infusion, median phase angle decreased significantly (p < 0.005 Wilcoxon) to 0.77 rad compared to a pre-test baseline value of 1.05 rad, indicating less efficient dCA due to ACZ. However, post-test phase values are still mostly within the normal range. Poor and statistically non-significant correlations were found between CVR and absolute dCA phase angle. It can be concluded that CVR testing with body weight adjusted infusion of ACZ lowers dCA performance but by no means exhausts dCA, suggesting that in this way maximal CVR is not determined. Characterizing dCA based on transfer function analysis of ABP to CBFV needs no provocation and adverse patient effects are minimal. The poor correlation between CVR and dCA phase angle supports an interpretation that CVR and dCA study different mechanisms of cerebrovascular control

  4. Cerebral Blood Flow Autoregulation and Dysautoregulation.

    Science.gov (United States)

    Armstead, William M

    2016-09-01

    This article provides a review of cerebral autoregulation, particularly as it relates to the clinician scientist experienced in neuroscience in anesthesia and critical care. Topics covered are biological mechanisms; methods used for assessment of autoregulation; effects of anesthetics; role in control of cerebral hemodynamics in health and disease; and emerging areas, such as role of age and sex in contribution to dysautoregulation. Emphasis is placed on bidirectional translational research wherein the clinical informs the study design of basic science studies, which, in turn, informs the clinical to result in development of improved therapies for treatment of central nervous system conditions. PMID:27521192

  5. Phase Synchronization of Pressure-Flow Fluctuations: A measure of cerebral autoregulation dynamics

    CERN Document Server

    Chen, Z; Ivanov, P C; Novák, V; Stanley, H E

    2006-01-01

    We employ a synchronization method to investigate the relationship between the blood flow velocities (BFV) in the middle cerebral arteries (MCA) and beat-to-beat blood pressure (BP) recorded from a finger in healthy and post-stroke subjects during four different physiologic conditions: supine, head-up tilt, hyperventilation and CO$_2$ rebreathing in upright position. To evaluate whether instantaneous BP changes are synchronized with changes in the BFV, we compare dynamical patterns in the instantaneous phases of these signals, obtained from the Hilbert transform, as a function of time. We find that in post-stroke subjects the instantaneous phase increments of BP and BFV exhibit well pronounced patterns that remain stable in time for all four physiologic conditions, while in healthy subjects these patterns are different, less pronounced and more variable. Further, we show that the instantaneous phase increments of BP and BFV are cross-correlated even within a single heartbeat cycle. The maximum correlation str...

  6. [Should cerebral autoregulation be reassessed?

    DEFF Research Database (Denmark)

    Secher, Niels H.

    2009-01-01

    Maintained cardiac output (CO) and cerebral oxygenation (ScO2) are of importance for a reduction in perioperative complications. Normovolaemia is defined as a central blood volume that does not limit CO for the supine patient and is maintained by individualized goal directed fluid therapy. Thereby...

  7. Cerebral autoregulation in pregnancies complicated by diabetes and overweight

    NARCIS (Netherlands)

    van Veen, Teelkien R.; Panerai, Ronney B.; Haeri, Sina; van den Berg, Paul P.; Zeeman, Gerda G.; Belfort, Michael A.

    2015-01-01

    Aim: The aim of this study was to estimate the impact of diabetes and obesity on cerebral autoregulation in pregnancy. Methods: Cerebral autoregulation was evaluated in women with gestational diabetes, type 2 diabetes mellitus and/or overweight (body mass index >= 25kgm(-2)) and compared to a cohort

  8. Cerebral autoregulation in different hypertensive disorders of pregnancy

    NARCIS (Netherlands)

    van Veen, Teelkien R.; Panerai, Ronney B.; Haeri, Sina; Singh, Jasbir; Adusumalli, Jasvant A.; Zeeman, Gerda G.; Belfort, Michael A.

    2015-01-01

    OBJECTIVE: Cerebrovascular complications that are associated with hypertensive disorders of pregnancy (preeclampsia, chronic hypertension [CHTN], and gestational hypertension [GHTN]) are believed to be associated with impaired cerebral autoregulation, which is a physiologic process that maintains bl

  9. Cerebral autoregulation in the first day after preterm birth

    DEFF Research Database (Denmark)

    Hahn, Gitte Holst; Maroun, Lisa L; Larsen, Nanna Brink;

    2012-01-01

    Both systemic inflammation and impaired cerebral autoregulation (CA) have been associated with brain injury in preterm infants. We hypothesized that impaired CA represents a hemodynamic link between inflammation and brain injury....

  10. Tracking time-varying cerebral autoregulation in response to changes in respiratory PaCO2

    International Nuclear Information System (INIS)

    Cerebral autoregulation has been studied by linear filter systems, with arterial blood pressure (ABP) as the input and cerebral blood flow velocity (CBFV—from transcranial Doppler Ultrasound) as the output. The current work extends this by using adaptive filters to investigate the dynamics of time-varying cerebral autoregulation during step-wise changes in arterial PaCO2. Cerebral autoregulation was transiently impaired in 11 normal adult volunteers, by switching inspiratory air to a CO2/air mixture (5% CO2, 30% O2 and 65% N2) for approximately 2 min and then back to the ambient air, causing step-wise changes in end-tidal CO2 (EtCO2). Simultaneously, ABP and CBFV were recorded continuously. Simulated data corresponding to the same protocol were also generated using an established physiological model, in order to refine the signal analysis methods. Autoregulation was quantified by the time-varying phase lead, estimated from the adaptive filter model. The adaptive filter was able to follow rapid changes in autoregulation, as was confirmed in the simulated data. In the recorded signals, there was a slow decrease in autoregulatory function following the step-wise increase in PaCO2 (but this did not reach a steady state within approximately 2 min of recording), with a more rapid change in autoregulation on return to normocapnia. Adaptive filter modelling was thus able to demonstrate time-varying autoregulation. It was further noted that impairment and recovery of autoregulation during transient increases in EtCO2 occur in an asymmetric manner, which should be taken into account when designing experimental protocols for the study of autoregulation

  11. Cerebral autoregulation control of blood flow in the brain

    CERN Document Server

    Payne, Stephen

    2016-01-01

    This Brief provides a comprehensive introduction to the control of blood flow in the brain. Beginning with the basic physiology of autoregulation, the author goes on to discuss measurement techniques, mathematical models, methods of analysis, and relevant clinical conditions, all within this single volume. The author draws together this disparate field, and lays the groundwork for future research directions. The text gives an up-to-date review of the state of the art in cerebral autoregulation, which is particularly relevant as cerebral autoregulation moves from the laboratory to the bedside. Cerebral Autoregulation will be useful to researchers in the physical sciences such as mathematical biology, medical physics, and biomedical engineering whose work is concerned with the brain. Researchers in the medical sciences and clinicians dealing with the brain and blood flow, as well as industry professionals developing techniques such as ultrasound, MRI, and CT will also find this Brief of interest.

  12. Intraaortic Balloon Pump Counterpulsation and Cerebral Autoregulation: an observational study

    OpenAIRE

    Boots Rob; Barnett Adrian G; Timms Daniel; Dunster Kimble; Geng Shureng; Bellapart Judith; Fraser John F

    2010-01-01

    Abstract Background The use of Intra-aortic counterpulsation is a well established supportive therapy for patients in cardiac failure or after cardiac surgery. Blood pressure variations induced by counterpulsation are transmitted to the cerebral arteries, challenging cerebral autoregulatory mechanisms in order to maintain a stable cerebral blood flow. This study aims to assess the effects on cerebral autoregulation and variability of cerebral blood flow due to intra-aortic balloon pump and in...

  13. Autonomic dysfunction and impaired cerebral autoregulation in cirrhosis

    DEFF Research Database (Denmark)

    Frøkjaer, Vibe G; Strauss, Gitte I; Mehlsen, Jesper;

    2006-01-01

    by norepinephrine infusion (NE). The severity of liver disease was assessed using the Child-Pugh scale (class A, mild; class B, moderate; class C, severe liver dysfunction).NE increased blood pressure similarly in the controls (27 (24-32) mmHg) and patients with the most severe liver cirrhosis (Child-Pugh C, 31 (26.......0+/-2.0 bpm) compared to the controls (21.7+/-2.2 bpm, p=0.001, Tukey' test). Systolic blood pressure fell during head-up tilt only in patients with severe cirrhosis. Our results imply that cerebral autoregulation was impaired in the most severe cases of liver cirrhosis, and that those with impaired cerebral......Cerebral blood flow autoregulation is lost in patients with severe liver cirrhosis. The cause of this is unknown. We determined whether autonomic dysfunction was related to impaired cerebral autoregulation in patients with cirrhosis. Fourteen patients with liver cirrhosis and 11 healthy volunteers...

  14. Autonomic dysfunction and impaired cerebral autoregulation in cirrhosis

    DEFF Research Database (Denmark)

    Frøkjaer, Vibe G; Mehlsen, Jesper; Knudsen, Gitte M;

    2006-01-01

    .0+/-2.0 bpm) compared to the controls (21.7+/-2.2 bpm, p=0.001, Tukey' test). Systolic blood pressure fell during head-up tilt only in patients with severe cirrhosis. Our results imply that cerebral autoregulation was impaired in the most severe cases of liver cirrhosis, and that those with impaired cerebral...

  15. Cerebrovascular reactivity and dynamic autoregulation in tetraplegia.

    Science.gov (United States)

    Wilson, Luke C; Cotter, James D; Fan, Jui-Lin; Lucas, Rebekah A I; Thomas, Kate N; Ainslie, Philip N

    2010-04-01

    Humans with spinal cord injury have impaired cardiovascular function proportional to the level and completeness of the lesion. The effect on cerebrovascular function is unclear, especially for high-level lesions. The purpose of this study was to evaluate the integrity of dynamic cerebral autoregulation (CA) and the cerebrovascular reactivity in chronic tetraplegia (Tetra). After baseline, steady-state hypercapnia (5% CO(2)) and hypocapnia (controlled hyperventilation) were used to assess cerebrovascular reactivity in 6 men with Tetra (C5-C7 lesion) and 14 men without [able-bodied (AB)]. Middle cerebral artery blood flow velocity (MCAv), cerebral oxygenation, arterial blood pressure (BP), heart rate (HR), cardiac output (Q; model flow), partial pressure of end-tidal CO(2) (Pet(CO(2))), and plasma catecholamines were measured. Dynamic CA was assessed by transfer function analysis of spontaneous fluctuations in BP and MCAv. MCAv pulsatility index (MCAv PI) was calculated as (MCAv(systolic) - MCAv(diastolic))/MCAv(mean) and standardized by dividing by mean arterial pressure (MAP). Resting BP, total peripheral resistance, and catecholamines were lower in Tetra (P 0.05). Although phase and transfer function gain relationships in dynamic CA were maintained with Tetra (P > 0.05), coherence in the very low-frequency range (0.02-0.07 Hz) was approximately 21% lower in Tetra (P = 0.006). Full (hypo- and hypercapnic) cerebrovascular reactivity to CO(2) was unchanged with Tetra (P > 0.05). During hypercapnia, standardized MCAv PI reactivity was enhanced by approximately 78% in Tetra (P = 0.016). Despite impaired cardiovascular function, chronic Tetra involves subtle changes in dynamic CA and cerebrovascular reactivity to CO(2). Changes are evident in coherence at baseline and MCAv PI during baseline and hypercapnic states in chronic Tetra, which may be indicative of cerebrovascular adaptation. PMID:20089710

  16. Autoregulation of cerebral blood flow in orthostatic hypotension

    Science.gov (United States)

    Novak, V.; Novak, P.; Spies, J. M.; Low, P. A.

    1998-01-01

    BACKGROUND AND PURPOSE: We sought to evaluate cerebral autoregulation in patients with orthostatic hypotension (OH). METHODS: We studied 21 patients (aged 52 to 78 years) with neurogenic OH during 80 degrees head-up tilt. Blood flow velocities (BFV) from the middle cerebral artery were continuously monitored with transcranial Doppler sonography, as were heart rate, blood pressure (BP), cardiac output, stroke volume, CO2, total peripheral resistance, and cerebrovascular resistance. RESULTS: All OH patients had lower BP (PTPR (P.75) but with a flat slope. An expansion of the "autoregulated" range was seen in some patients. The OH_AF group was characterized by a profound fall in BFV in response to a small reduction in BP (mean deltaBP .75). CONCLUSIONS: The most common patterns of cerebral response to OH are autoregulatory failure with a flat flow-pressure relationship or intact autoregulation with an expanded autoregulated range. The least common pattern is autoregulatory failure with a steep flow-pressure relationship. Patients with patterns 1 and 2 have an enhanced capacity to cope with OH, while those with pattern 3 have reduced capacity.

  17. In vivo cerebral blood flow autoregulation studies using rheoencephalography

    Science.gov (United States)

    Bodo, M.; Pearce, F.; Garcia, A.; Van Albert, S.; Settle, T.; Szebeni, J.; Baranyi, L.; Hartings, J.; Armonda, R.

    2010-04-01

    Acute management of patients with traumatic brain/blast injury is a challenge. To minimize secondary injury and improve outcome, it is critical to detect neurological deterioration early, when it is potentially reversible. One potential monitoring method is cerebral electrical impedance (rheoencephalography-REG) because of its non-invasiveness and good time resolution. Reported here are the results of cerebral blood flow (CBF) manipulations comparing electroencephalogram (EEG) with REG (both intra-cerebral) and measuring with surface and skull REG electrodes. Our hypothesis was that REG would reflect spreading depression and CBF autoregulation. Animal experiments were performed using one rat (four trials with intracerebral electrodes), monkeys (n=8, with surface electrodes) and pigs (n = 24 pigs with skull electrodes; 57 trials, 19 types of liposomes). Challenges included intracranial pressure (ICP) elevation, liposome infusion, and hemorrhage. Data were stored on a PC and evaluated off line. CBF autoregulation was evaluated both by visual inspection and by a Matlab script. These studies confirmed that REG reflects CBF autoregulation and that REG is useful for detecting spreading depression (SD), vasospasm and the lower limit of CBF autoregulation. These findings have clinical relevance for use in noninvasive neuro-monitoring in the neurosurgery intensive care and during transportation of patients with brain injury.

  18. Cerebral blood flow autoregulation in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten

    2001-01-01

    Ph.d. afhandlingen omhandler sammenhængen mellem hjernens blodtilførsel (CBF) og middelarterietrykket (MAP) hos patienter med akut bakteriel meningitis. Hos raske er CBF uafhængig af MAP, hvilket kaldes CBF autoregulation. Svækket autoregulation antages at øge risikoen for cerebral hypoperfusion og...... iskæmi under episoder med lavt MAP, og for cerebral hyperperfusion og vasogent ødem ved højt MAP. CBF autoregulationen undersøgtes hos tyve voksne patienter med akut bakteriel meningitis i den tidlige sygdomsfase (... meningitis, men retableres ved klinisk restitution. Autoregulationen kan endvidere delvis retableres ved akut hyperventilation. Fundene har potentiel betydning for valg af supportiv terapi hos patienter med meningitis....

  19. Effects of autoregulation and CO2 reactivity on cerebral oxygen transport.

    Science.gov (United States)

    Payne, S J; Selb, J; Boas, D A

    2009-11-01

    Both autoregulation and CO(2) reactivity are known to have significant effects on cerebral blood flow and thus on the transport of oxygen through the vasculature. In this paper, a previous model of the autoregulation of blood flow in the cerebral vasculature is expanded to include the dynamic behavior of oxygen transport through binding with hemoglobin. The model is used to predict the transfer functions for both oxyhemoglobin and deoxyhemoglobin in response to fluctuations in arterial blood pressure and arterial CO(2) concentration. It is shown that only six additional nondimensional groups are required in addition to the five that were previously found to characterize the cerebral blood flow response. A resonant frequency in the pressure-oxyhemoglobin transfer function is found to occur in the region of 0.1 Hz, which is a frequency of considerable physiological interest. The model predictions are compared with results from the published literature of phase angle at this frequency, showing that the effects of changes in breathing rate can significantly alter the inferred phase dynamics between blood pressure and hemoglobin. The question of whether dynamic cerebral autoregulation is affected under conditions of stenosis or stroke is then examined.

  20. Myogenic and metabolic feedback in cerebral autoregulation: Putative involvement of arachidonic acid-dependent pathways.

    Science.gov (United States)

    Berg, Ronan M G

    2016-07-01

    The present paper presents a mechanistic model of cerebral autoregulation, in which the dual effects of the arachidonic acid metabolites 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) on vascular smooth muscle mediate the cerebrovascular adjustments to a change in cerebral perfusion pressure (CPP). 20-HETE signalling in vascular smooth muscle mediates myogenic feedback to changes in vessel wall stretch, which may be modulated by metabolic feedback through EETs released from astrocytes and endothelial cells in response to changes in brain tissue oxygen tension. The metabolic feedback pathway is much faster than 20-HETE-dependent myogenic feedback, and the former thus initiates the cerebral autoregulatory response, while myogenic feedback comprises a relatively slower mechanism that functions to set the basal cerebrovascular tone. Therefore, assessments of dynamic cerebral autoregulation, which may provide information on the response time of the cerebrovasculature, may specifically be used to yield information on metabolic feedback mechanisms, while data based on assessments of static cerebral autoregulation represent the integrated functionality of myogenic and metabolic feedback. PMID:27241246

  1. Cerebral blood flow autoregulation in hypertension and effects of antihypertensive drugs

    DEFF Research Database (Denmark)

    Barry, David; Lassen, N A

    1984-01-01

    If antihypertensive treatment, especially emergency blood pressure lowering, is always to be safe, more thought should be given to autoregulation of cerebral blood in the hypertensive patient. This topic is reviewed in the present article, in the hypertensive patient. This topic is reviewed...... in the present article, particular emphasis being placed on the resetting of the lower limit of autoregulation to higher pressure in hypertension and the effects of acute administration of anti-hypertensive drugs on CBF and CBF-autoregulation....

  2. Regional cerebral blood flow autoregulation in patients with fulminant hepatic failure

    DEFF Research Database (Denmark)

    Larsen, Fin Stolze; Strauss, Gitte Irene; Møller, Kirsten;

    2000-01-01

    The absence of cerebral blood flow autoregulation in patients with fulminant hepatic failure (FHF) implies that changes in arterial pressure directly influence cerebral perfusion. It is assumed that dilatation of cerebral arterioles is responsible for the impaired autoregulation. Recently, frontal...... blood flow was reported to be lower compared with other brain regions, indicating greater arteriolar tone and perhaps preserved regional cerebral autoregulation. In patients with severe FHF (6 women, 1 man; median age, 46 years; range, 18 to 55 years), we tested the hypothesis that perfusion...... in the anterior cerebral artery would be less affected by an increase in mean arterial pressure compared with the brain area supplied by the middle cerebral artery. Relative changes in cerebral perfusion were determined by transcranial Doppler-measured mean flow velocity (V(mean)), and resistance was determined...

  3. Secondary decline of cerebral autoregulation is associated with worse outcome after intracerebral hemorrhage

    DEFF Research Database (Denmark)

    Reinhard, Matthias; Neunhoeffer, Florian; Gerds, Thomas A;

    2010-01-01

    and 5 after ictus. Autoregulation was noninvasively measured from spontaneous fluctuations of blood pressure and middle cerebral artery flow velocity (assessed by transcranial Doppler) using the correlation coefficient index Mx. From the same signals, non-invasive cerebral perfusion pressure was......PURPOSE: Blood pressure management in acute intracerebral hemorrhage (ICH) relies on functioning cerebral autoregulation. The time course of autoregulation in acute ICH and its relation with clinical outcome are not known. METHODS: Twenty-six patients with spontaneous ICH were studied on days 1, 3...... related with lower Glasgow coma score, ventricular hemorrhage (both sides) and lower noninvasive cerebral perfusion pressure (ipsilateral). Increasing ipsilateral Mx between days 3 and 5 was related with lower Glasgow coma score and ventricular hemorrhage. In a multivariate analysis controlling for other...

  4. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral cir...

  5. Impaired Cerebral Autoregulation Using Near-Infrared Spectroscopy and Its Relation to Clinical Outcomes in Premature Infants

    NARCIS (Netherlands)

    Caicedo, Alexander; De Smet, Dominique; Vanderhaegen, Joke; Naulaers, Gunnar; Wolf, Martin; Lemmers, Petra; Van Bel, Frank; Ameye, Lieveke; Van Huffel, Sabine; LaManna, JC; Puchowicz, MA; Xu, K; Harrison, DK; Bruley, DF

    2011-01-01

    The concordance between the change in the Mean Arterial Blood Pressure (MABP) and the Cerebral Blood Flow (CBF) is studied using the Correlation, Coherence and Partial Coherence methods in order to detect Impaired Cerebral Autoregulation in Neonates. The presence of impaired autoregulation is assess

  6. Impaired cerebral autoregulation is associated with brain atrophy and worse functional status in chronic ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Mikio C Aoi

    Full Text Available Dynamic cerebral autoregulation (dCA is impaired following stroke. However, the relationship between dCA, brain atrophy, and functional outcomes following stroke remains unclear. In this study, we aimed to determine whether impairment of dCA is associated with atrophy in specific regions or globally, thereby affecting daily functions in stroke patients.We performed a retrospective analysis of 33 subjects with chronic infarctions in the middle cerebral artery territory, and 109 age-matched non-stroke subjects. dCA was assessed via the phase relationship between arterial blood pressure and cerebral blood flow velocity. Brain tissue volumes were quantified from MRI. Functional status was assessed by gait speed, instrumental activities of daily living (IADL, modified Rankin Scale, and NIH Stroke Score.Compared to the non-stroke group, stroke subjects showed degraded dCA bilaterally, and showed gray matter atrophy in the frontal, parietal and temporal lobes ipsilateral to infarct. In stroke subjects, better dCA was associated with less temporal lobe gray matter atrophy on the infracted side ([Formula: see text] = 0.029, faster gait speed ([Formula: see text] = 0.018 and lower IADL score ([Formula: see text]0.002. Our results indicate that better dynamic cerebral perfusion regulation is associated with less atrophy and better long-term functional status in older adults with chronic ischemic infarctions.

  7. Impaired Cerebral Autoregulation during Head Up Tilt in Patients with Severe Brain Injury.

    Directory of Open Access Journals (Sweden)

    Christian Gunge Riberholt

    Full Text Available Early mobilization is of importance for improving long-term outcome for patients after severe acquired brain injury. A limiting factor for early mobilization by head-up tilt is orthostatic intolerance. The purpose of the present study was to examine cerebral autoregulation in patients with severe acquired brain injury and a low level of consciousness. Fourteen patients with severe acquired brain injury and orthostatic intolerance and fifteen healthy volunteers were enrolled. Blood pressure was evaluated by pulse contour analysis, heart rate and RR-intervals were determined by electrocardiography, middle cerebral artery velocity was evaluated by transcranial Doppler, and near-infrared spectroscopy determined frontal lobe oxygenation in the supine position and during head-up tilt. Cerebral autoregulation was evaluated as the mean flow index calculated as the ratio between middle cerebral artery mean velocity and estimated cerebral perfusion pressure. Patients with acquired brain injury presented an increase in mean flow index during head-up tilt indicating impaired autoregulation (P < 0.001. Spectral analysis of heart rate variability in the frequency domain revealed lower magnitudes of ~0.1 Hz spectral power in patients compared to healthy controls suggesting baroreflex dysfunction. In conclusion, patients with severe acquired brain injury and orthostatic intolerance during head-up tilt have impaired cerebral autoregulation more than one month after brain injury.

  8. Impaired Cerebral Autoregulation during Head Up Tilt in Patients with Severe Brain Injury

    DEFF Research Database (Denmark)

    Riberholt, Christian Gunge; Olesen, Niels Damkjær; Thing, Mira;

    2016-01-01

    acquired brain injury and a low level of consciousness. Fourteen patients with severe acquired brain injury and orthostatic intolerance and fifteen healthy volunteers were enrolled. Blood pressure was evaluated by pulse contour analysis, heart rate and RR-intervals were determined by electrocardiography...... mean velocity and estimated cerebral perfusion pressure. Patients with acquired brain injury presented an increase in mean flow index during head-up tilt indicating impaired autoregulation (P ....1 Hz spectral power in patients compared to healthy controls suggesting baroreflex dysfunction. In conclusion, patients with severe acquired brain injury and orthostatic intolerance during head-up tilt have impaired cerebral autoregulation more than one month after brain injury....

  9. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral...... circulation is uncertain. Hence, the present study investigated the effect on CBF autoregulation of blocking of angiotensin AT2-receptors with PD 123319 in spontaneously hypertensive rats (SHR). Anaesthetised and ventilated SHR were given PD 123319, 0.36 mg/kg/min, intravenously, and compared with a control...

  10. Altered phase interactions between spontaneous blood pressure and flow fluctuations in type 2 diabetes mellitus: Nonlinear assessment of cerebral autoregulation

    Science.gov (United States)

    Hu, Kun; Peng, C. K.; Huang, Norden E.; Wu, Zhaohua; Lipsitz, Lewis A.; Cavallerano, Jerry; Novak, Vera

    2008-04-01

    Cerebral autoregulation is an important mechanism that involves dilatation and constriction in arterioles to maintain relatively stable cerebral blood flow in response to changes of systemic blood pressure. Traditional assessments of autoregulation focus on the changes of cerebral blood flow velocity in response to large blood pressure fluctuations induced by interventions. This approach is not feasible for patients with impaired autoregulation or cardiovascular regulation. Here we propose a newly developed technique-the multimodal pressure-flow (MMPF) analysis, which assesses autoregulation by quantifying nonlinear phase interactions between spontaneous oscillations in blood pressure and flow velocity during resting conditions. We show that cerebral autoregulation in healthy subjects can be characterized by specific phase shifts between spontaneous blood pressure and flow velocity oscillations, and the phase shifts are significantly reduced in diabetic subjects. Smaller phase shifts between oscillations in the two variables indicate more passive dependence of blood flow velocity on blood pressure, thus suggesting impaired cerebral autoregulation. Moreover, the reduction of the phase shifts in diabetes is observed not only in previously-recognized effective region of cerebral autoregulation (type 2 diabetes mellitus alters cerebral blood flow regulation over a wide frequency range and that this alteration can be reliably assessed from spontaneous oscillations in blood pressure and blood flow velocity during resting conditions. We also show that the MMPF method has better performance than traditional approaches based on Fourier transform, and is more suitable for the quantification of nonlinear phase interactions between nonstationary biological signals such as blood pressure and blood flow.

  11. Effect of short-term hyperventilation on cerebral blood flow autoregulation in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten

    2000-01-01

    BACKGROUND AND PURPOSE: Cerebral blood flow (CBF) autoregulation is impaired in patients with acute bacterial meningitis: this may be caused by cerebral arteriolar dilatation. We tested the hypothesis that CBF autoregulation is recovered by acute mechanical hyperventilation in 9 adult patients...... with acute bacterial meningitis. METHODS: Norepinephrine was infused to increase mean arterial pressure (MAP) 30 mm Hg from baseline. Relative changes in CBF were concomitantly recorded by transcranial Doppler ultrasonography of the middle cerebral artery, measuring mean flow velocity (V...... completely during hyperventilation. The slope of the autoregulation curve decreased during hyperventilation compared with normoventilation (Pmeningitis, indicating...

  12. The effect of Ventricular Assist Devices on cerebral autoregulation: A preliminary study

    Directory of Open Access Journals (Sweden)

    Dunster Kimble R

    2011-02-01

    Full Text Available Abstract Background The insertion of Ventricular Assist Devices is a common strategy for cardiovascular support in patients with refractory cardiogenic shock. This study sought to determine the impact of ventricular assist devices on the dynamic relationship between arterial blood pressure and cerebral blood flow velocity. Methods A sample of 5 patients supported with a pulsatile ventricular assist device was compared with 5 control patients. Controls were matched for age, co-morbidities, current diagnosis and cardiac output state, to cases. Beat-to-beat recordings of mean arterial pressure and cerebral blood flow velocity, using transcranial Doppler were obtained. Transfer function analysis was performed on the lowpass filtered pressure and flow signals, to assess gain, phase and coherence of the relationship between mean arterial blood pressure and cerebral blood flow velocity. These parameters were derived from the very low frequency (0.02-0.07 Hz, low frequency (0.07-0.2 Hz and high frequency (0.2-0.35 Hz. Results No significant difference was found in gain and phase values between the two groups, but the low frequency coherence was significantly higher in cases compared with controls (mean ± SD: 0.65 ± 0.16 vs 0.38 ± 0.19, P = 0.04. The two cases with highest coherence (~0.8 also had much higher spectral power in mean arterial blood pressure. Conclusions Pulsatile ventricular assist devices affect the coherence but not the gain or phase of the cerebral pressure-flow relationship in the low frequency range; thus whether there was any significant disruption of cerebral autoregulation mechanism was not exactly clear. The augmentation of input pressure fluctuations might contribute in part to the higher coherence observed.

  13. Precision of coherence analysis to detect cerebral autoregulation by near-infrared spectroscopy in preterm infants

    DEFF Research Database (Denmark)

    Hahn, GH; Christensen, KB; Leung, TS;

    2010-01-01

    Coherence between spontaneous fluctuations in arterial blood pressure (ABP) and the cerebral near-infrared spectroscopy signal can detect cerebral autoregulation. Because reliable measurement depends on signals with high signal-to-noise ratio, we hypothesized that coherence is more precisely...... for the variabilityABP among repeated measurements (i.e., weighting measurements with high variabilityABP in favor of those with low) improved the precision. The evidence of drift in individual infants was weak. Minimum monitoring time needed to discriminate among infants was 1.3–3.7 h. Coherence analysis in low...... frequencies (0.04–0.1 Hz) had higher precision and statistically more power than in very low frequencies (0.003–0.04 Hz). In conclusion, a reliable detection of cerebral autoregulation takes hours and the precision is improved by adjusting for variabilityABP between repeated measurements....

  14. Testing impact of perinatal inflammation on cerebral autoregulation in preterm neonates

    DEFF Research Database (Denmark)

    Hahn, Gitte Holst

    2013-01-01

    Increased preterm delivery rate and survival of preterm infants of whom a considerable proportion survive with neurodevelopmental impairment calls for better knowledge of mechanisms associated with brain injury. This thesis focuses on cerebral autoregulation and is based on clinical studies of very...... us to evaluate the precision and validity of this method. We monitored 22 preterm neonates and demonstrated that reliable detection of impaired cerebral autoregulation requires several hours of monitoring. However, weighting measurements with large variations in blood pressure in favour of those......). This mismatch has formed the basis for an ongoing explanatory study. Based on the findings in the present thesis we conclude the following: Our non-invasive method has potential use in clinical research. However, low precision hampers its clinical application. In preterm infants with perinatal inflammation...

  15. The effect of S. pneumoniae bacteremia on cerebral blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Pedersen, Michael; Brandt, Christian T.; Knudsen, Gitte Moos;

    2008-01-01

    In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally......); or saline intravenously and saline intracisternally (group E, N=10), respectively. Positive cultures occurred in the blood for all rats in groups A, B, and C, and in the cerebrospinal fluid for all rats in groups D and E. Twenty-four hours after inoculation, CBF was measured with laser-Doppler ultrasound...... during incremental reductions in cerebral perfusion pressure (CPP) by controlled hemorrhage. Autoregulation was preserved in all rats without meningitis (groups A and E) and was lost in 24 of 25 meningitis rats (groups B, C, and D) (P

  16. Modelling Cerebrovascular Reactivity: A Novel Near-Infrared Biomarker of Cerebral Autoregulation?

    OpenAIRE

    Highton, D.; Panovska-Griffiths, J; Ghosh, A; Tachtsidis, I; Banaji, M.; Elwell, C.; Smith, M.

    2013-01-01

    Understanding changes in cerebral oxygenation, haemodynamics and metabolism holds the key to individualised, optimised therapy after acute brain injury. Near-infrared spectroscopy (NIRS) offers the potential for non-invasive, continuous bedside measurement of surrogates for these processes. Interest has grown in applying this technique to interpret cerebrovascular pressure reactivity (CVPR), a surrogate of the brain's ability to autoregulate blood flow. We describe a physiological model-based...

  17. Near-infrared spectroscopy for evaluation of cerebral autoregulation during orthotopic liver transplantation

    DEFF Research Database (Denmark)

    Nissen, P.; Pacino, H.; Frederiksen, H.J.;

    2009-01-01

    detected, S(c)O(2) varied in parallel with mean arterial pressure (MAP) for 3 patients and, therefore, an autoregulation curve could not be established and yet, there was detected no change in S(c)O(2) to a lowest MAP ranging from 42 to 66 mmHg for 20 patients, while for 8 patients a decrease in S(c)O(2......) was detected at a MAP of 69 (50-90) mmHg; (median and range). As detected by NIRS, the present study confirms that some patients undergoing liver transplantation do not demonstrate cerebral autoregulation but for the majority of the patients, S(c)O(2) was stable over a wide range of MAP suggesting......INTRODUCTION: The present study evaluated whether frontal lobe cerebral oxygenation (S(c)O(2)), as assessed by near-infrared spectroscopy (NIRS), can detect cerebral autoregulation in patients undergoing orthotopic liver transplantation. METHODS: We studied changes in frontal lobe S(c)O(2) assessed...

  18. Impaired cerebral autoregulation using near-infrared spectroscopy and its relation to clinical outcomes in premature infants.

    Science.gov (United States)

    Caicedo, Alexander; De Smet, Dominique; Vanderhaegen, Joke; Naulaers, Gunnar; Wolf, Martin; Lemmers, Petra; Van Bel, Frank; Ameye, Lieveke; Van Huffel, Sabine

    2011-01-01

    The concordance between the change in the Mean Arterial Blood Pressure (MABP) and the Cerebral Blood Flow (CBF) is studied using the Correlation, Coherence and Partial Coherence methods in order to detect Impaired Cerebral Autoregulation in Neonates. The presence of impaired autoregulation is assessed by the use of the Critical Percentage of Recording Time (CPRT). The changes in CBF are reflected by the measurement of changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO(2)), and cerebral tissue oxygenation (TOI), as measured by Near-Infrared Spectroscopy (NIRS) (INVOS4100 and NIRO300). The relation between impaired autoregulation and long term clinical outcomes in premature infants is studied. PMID:21445792

  19. Statistical criteria for estimation of the cerebral autoregulation index (ARI) at rest.

    Science.gov (United States)

    Panerai, R B; Haunton, V J; Hanby, M F; Salinet, A S M; Robinson, T G

    2016-05-01

    The autoregulation index (ARI) can reflect the effectiveness of cerebral blood flow (CBF) control in response to dynamic changes in arterial blood pressure (BP), but objective criteria for its validation have not been proposed. Monte Carlo simulations were performed by generating 5 min long random input/output signals that mimic the properties of mean beat-to-beat BP and CBF velocity (CBFV) as usually obtained by non-invasive measurements in the finger (Finometer) and middle cerebral artery (transcranial Doppler ultrasound), respectively. Transfer function analysis (TFA) was used to estimate values of ARI by optimal fitting of template curves to the output (or CBFV) response to a step change in input (or BP). Two-step criteria were adopted to accept estimates of ARI as valid. The 95% confidence limit of the mean coherence function (0.15-0.25 Hz) ([Formula: see text]) was estimated from 15 000 runs, resulting in [Formula: see text]  =  0.190 when using five segments of data, each with 102.4 s (512 samples) duration (Welch's method). This threshold for acceptance was dependent on the TFA settings and increased when using segments with shorter duration (51.2 s). For signals with mean coherence above the critical value, the 5% confidence limit of the normalised mean square error (NMSEcrit) for fitting the step response to Tieck's model, was found to be approximately 0.30 and independent of the TFA settings. Application of these criteria to physiological and clinical sets of data showed their ability to identify conditions where ARI estimates should be rejected, for example due to CBFV step responses lacking physiological plausibility. A larger number of recordings were rejected from acute ischaemic stroke patients than for healthy volunteers. More work is needed to validate this procedure with different physiological conditions and/or patient groups. The influence of non-stationarity in BP and CBFV signals should also be investigated. PMID:27093173

  20. Dopamine therapy is associated with impaired cerebral autoregulation in preterm infants

    DEFF Research Database (Denmark)

    Eriksen, Vibeke R; Hahn, Gitte H; Greisen, Gorm

    2014-01-01

    , but the anticipated difference in cerebral oxygenation was not detected. The need for mechanical ventilation in the first day of life and incidences of mortality was higher in the dopamine group. CONCLUSION: Dopamine therapy was associated with decreased CA in preterm infants. We were unable to determine whether......AIM: Hypotension is a common problem in newborn infants and is associated with increased mortality and morbidity. Dopamine is the most commonly used antihypotensive drug therapy, but has never been shown to improve neurological outcomes. This study tested our hypothesis that dopamine affects...... cerebral autoregulation (CA). METHODS: Near-infrared spectroscopy was used to measure the cerebral oxygenation index in 60 very preterm infants, and mean arterial blood pressure was monitored towards the end of their first day of life. Measurements were performed continuously for two to three hour periods...

  1. Cerebral vascular autoregulation and CO2 reactivity following onset of the delayed postischemic hypoperfusion state in dogs.

    Science.gov (United States)

    Christopherson, T J; Milde, J H; Michenfelder, J D

    1993-03-01

    A small number of animal studies have suggested that during the delayed postischemic hypoperfusion state, CO2 reactivity of the cerebral vasculature is lost whereas autoregulation is retained. These findings, however, are inconsistent with the bulk of experimental evidence which demonstrates that CO2 reactivity is more robust and may be retained in pathologic circumstances which abolish autoregulation. These opposing viewpoints were therefore further evaluated in 18 dogs in which complete global ischemia was induced by cerebrospinal fluid (CSF) compression for periods of 12 (n = 12) and 18 (n = 6) min. Following 45 min of reperfusion and with onset of the delayed postischemic hypoperfusion state, autoregulation and CO2 reactivity were evaluated using a continuous measurement of CBF (by sagittal sinus outflow). CO2 reactivity was tested over a PaCO2 range of 20 to 60 mm Hg; autoregulation was tested over a blood pressure range of 60 to 140 mm Hg. Results demonstrated that after both 12 and 18 min of complete global ischemia, autoregulation and CO2 reactivity of the cerebral vasculature were both present, but attenuated. In the case of CO2 reactivity, the slope of the CBF response was decreased approximately 75%. In the case of autoregulation, the response in some dogs was incomplete as compared with their preischemic response. PMID:8436617

  2. What is the optimal anesthetic protocol for measurements of cerebral autoregulation in spontaneously breathing mice?

    Science.gov (United States)

    Wang, Zhenghui; Schuler, Beat; Vogel, Olga; Arras, Margarete; Vogel, Johannes

    2010-12-01

    Autoregulation, an important feature of the cerebral circulation, is affected in many diseases. Since genetically modified mice are a fundamental tool in biomedical research, including neuro(bio)logy also in this specie measurements of cerebral autoregulation (CA) are mandatory. However, this requires anesthesia that unfortunately significantly impacts cerebral perfusion and consequently might distort CA measurements directly or by altering arterial pCO(2). The latter can be avoided by artificial ventilation but requires several control measurements of blood gases, each consuming at least 100 μl of blood or 5% of a mouse's blood volume. To avoid such diagnostic hemorrhage, we systematically analyzed the effect of different common anesthetic protocols used for rodents in spontaneously breathing mice on CA measured with Laser speckle perfusion imaging. Halothane, Isoflurane and Pentobarbital abrogated CA and Ketamin/Xylazine as well as Chloralose had a moderate reproducibility. In contrast, the rather rarely used anesthetic Ethomidate applied in low doses combined with local anesthetics had the best reproducibility. Although with this anesthesia the lower CA limit was lower than with Ketamin/Xylazine and Chloralose as reported in the handful of papers so far dealing with CA in mice, we suggest Ethomidate as the anesthetic of choice for CA measurements in spontaneously breathing mice.

  3. Precision of coherence analysis to detect cerebral autoregulation by near-infrared spectroscopy in preterm infants

    Science.gov (United States)

    Hahn, Gitte Holst; Christensen, Karl Bang; Leung, Terence S.; Greisen, Gorm

    2010-05-01

    Coherence between spontaneous fluctuations in arterial blood pressure (ABP) and the cerebral near-infrared spectroscopy signal can detect cerebral autoregulation. Because reliable measurement depends on signals with high signal-to-noise ratio, we hypothesized that coherence is more precisely determined when fluctuations in ABP are large rather than small. Therefore, we investigated whether adjusting for variability in ABP (variabilityABP) improves precision. We examined the impact of variabilityABP within the power spectrum in each measurement and between repeated measurements in preterm infants. We also examined total monitoring time required to discriminate among infants with a simulation study. We studied 22 preterm infants (GA<30) yielding 215 10-min measurements. Surprisingly, adjusting for variabilityABP within the power spectrum did not improve the precision. However, adjusting for the variabilityABP among repeated measurements (i.e., weighting measurements with high variabilityABP in favor of those with low) improved the precision. The evidence of drift in individual infants was weak. Minimum monitoring time needed to discriminate among infants was 1.3-3.7 h. Coherence analysis in low frequencies (0.04-0.1 Hz) had higher precision and statistically more power than in very low frequencies (0.003-0.04 Hz). In conclusion, a reliable detection of cerebral autoregulation takes hours and the precision is improved by adjusting for variabilityABP between repeated measurements.

  4. Disassociation of Static and Dynamic Cerebral Autoregulatory Performance in Healthy Volunteers After Lipopolysaccharide Infusion and in Patients with Sepsis

    DEFF Research Database (Denmark)

    Berg, Ronan Martin Griffin; Plovsing, Ronni R.; Ronit, Andreas;

    2012-01-01

    with sepsis (n=16). Static autoregulation was tested by norepinephrine infusion and dynamic autoregulation by transfer function analysis (TFA) of spontaneous oscillations between mean arterial blood pressure and middle cerebral artery blood flow velocity in the low frequency range (0.07-0.20 Hz). Static......Sepsis is frequently complicated by brain dysfunction, which may be associated with disturbances in cerebral autoregulation rendering the brain susceptible to hypo- and hyperperfusion. The purpose of the present study was to assess static and dynamic cerebral autoregulation (i) in a human......); patients exhibited similar gain but lower phase difference values (p static and dynamic cerebral autoregulatory performance may disassociate in sepsis; thus static autoregulation was maintained both...

  5. Investigation of cerebral autoregulation in the newborn piglet during anaesthesia and surgery.

    Science.gov (United States)

    Bale, Gemma; Oliver-Taylor, Aaron; Fierens, Igor; Broad, Kevin; Hassell, Jane; Kawano, Go; Rostami, Jamshid; Raivich, Gennadij; Sanders, Robert; Robertson, Nicola; Tachtsidis, Ilias

    2014-01-01

    The relationship between cerebral autoregulation (CA) and the neurotoxic effects of anaesthesia with and without surgery is investigated. Newborn piglets were randomly assigned to receive either 6 h of anaesthesia (isoflurane) or the same with an additional hour of minor surgery. The effect of the spontaneous changes in mean arterial blood pressure (MABP) on the cerebral haemodynamics (oxy- and deoxy-haemoglobin, HbO2 and Hb) was measured using transverse broadband near-infrared spectroscopy (NIRS). A marker for impaired CA, concordance between MABP and intravascular oxygenation (HbD = HbO2 - Hb) in the ultra-low frequency domain (0.0018-0.0083 Hz), was assessed using coherence analysis. Presence of CA impairment was not significant but found to increase with surgical exacerbation. The impairment did not correlate with histological outcome (presence of cell death, apoptosis and microglial activation in the brain). PMID:24729229

  6. Assessment of cerebral blood flow autoregulation (CBF AR) with rheoencephalography (REG): studies in animals

    International Nuclear Information System (INIS)

    The ability of cerebral vasculature to regulate cerebral blood flow (CBF) in the face of changes in arterial blood pressure (SAP) or intracranial pressure (ICP) is an important guard against secondary ischemia in acute brain injuries, and official guidelines recommend that therapeutic decisions be guided by continuous monitoring of CBF autoregulation (AR). The common method for CBF AR monitoring, which rests on real-time derivation of the correlation coefficient (PRx) between slow oscillations in SAP and ICP is, however, rarely used in clinical practice because it requires invasive ICP measurements. This study investigated whether the correlation coefficient between SAP and the pulsatile component of the non-invasive transcranial bioimpedance signal (rheoencephalography, REG) could be used to assess the state and lower limit of CBF AR. The results from pigs and rhesus macaques affirm the utility of REG; however, additional animal and clinical studies are warranted to assess selectivity of automatic REG-based evaluation of CBF AR.

  7. Assessment of cerebral blood flow autoregulation (CBF AR) with rheoencephalography (REG): studies in animals

    Science.gov (United States)

    Popovic, Djordje; Bodo, Michael; Pearce, Frederick; van Albert, Stephen; Garcia, Alison; Settle, Tim; Armonda, Rocco

    2013-04-01

    The ability of cerebral vasculature to regulate cerebral blood flow (CBF) in the face of changes in arterial blood pressure (SAP) or intracranial pressure (ICP) is an important guard against secondary ischemia in acute brain injuries, and official guidelines recommend that therapeutic decisions be guided by continuous monitoring of CBF autoregulation (AR). The common method for CBF AR monitoring, which rests on real-time derivation of the correlation coefficient (PRx) between slow oscillations in SAP and ICP is, however, rarely used in clinical practice because it requires invasive ICP measurements. This study investigated whether the correlation coefficient between SAP and the pulsatile component of the non-invasive transcranial bioimpedance signal (rheoencephalography, REG) could be used to assess the state and lower limit of CBF AR. The results from pigs and rhesus macaques affirm the utility of REG; however, additional animal and clinical studies are warranted to assess selectivity of automatic REG-based evaluation of CBF AR.

  8. Cardiovascular and Postural Control Interactions during Hypergravity: Effects on Cerebral Autoregulation in Males and Females

    Science.gov (United States)

    Goswami, Nandu; Blaber, Andrew; Bareille, Marie-Pierre; Beck, Arnaud; Avan, Paul; Bruner, Michelle; Hinghofer-Szalkay, Helmut

    2012-07-01

    Orthostatic intolerance remains a problem upon return to Earth from the microgravity environment of spaceflight. A variety of conditions including hypovolemia, cerebral vasoconstriction, cerebral or peripheral vascular disease, or cardiac arrhythmias may result in syncope if the person remains upright. Current research indicates that there is a greater dependence on visual and somatosensory information at the beginning of space flight with a decreased otolith gain during prolonged space flight (Herault et al., 2002). The goal of the research is to further our understanding of the fundamental adaptive homeostatic mechanisms involved in gravity related changes in cardiovascular and postural function. Cardiovascular, cerebrovascular, and postural sensory motor control systems in male and female participants before, during, and after exposure to graded levels of hyper-G were investigated. Hypotheses: 1) Activation of skeletal muscle pump will be directly related to the degree of orthostatic stress. 2) Simultaneous measurement of heart rate, blood pressure and postural sway will predict cardio-postural stability. Blood pressure and heart rate (means and variability), postural sway, center of pressure (COP), baroreflex function, calf blood flow, middle cerebral artery blood flow, non-invasive intracranial pressure measurements, and two-breath CO2 were measured. Results from the study will be used to provide an integrated insight into mechanisms of cardio-postural control and cerebral autoregulation, which are important aspects of human health in flights to Moon, Mars and distant planets.

  9. Optimization of the coherence measurement computed by means of the Welch averaged periodogram method for assessment of impaired cerebral autoregulation.

    Science.gov (United States)

    De Smet, D; Vanderhaegen, J; Naulaers, G; Van Huffel, S

    2010-01-01

    The coherence method (COH) has been widely used to study the concordance between continuously measured signals intervening in the assessment of cerebral autoregulation in neonates. Several research groups have applied this method to mean arterial blood pressure (MABP) combined with cerebral signals such as the intravascular oxygenation (HbD), cerebral tissue oxygenation (TOI), and regional oxygen saturation (rSO(2)) measured by near-infrared spectroscopy (NIRS). All groups contributed in a particular way to the fine-tuning of the application of COH with the Welch averaged periodogram (WAP) method. We have made a comparative study of all published results coupled with an optimization of the use of the WAP method within COH. We have also proposed a pre-processing algorithm to remove signal artefacts, and defined a new critical score value (CSV) for COH to distinguish infants with impaired autoregulation from those without. PMID:20204787

  10. A single subcutaneous bolus of erythropoietin normalizes cerebral blood flow autoregulation after subarachnoid haemorrhage in rats

    DEFF Research Database (Denmark)

    Springborg, Jacob Bertram; Ma, XiaoDong; Rochat, Per;

    2002-01-01

    Systemic administration of recombinant erythropoietin (EPO) has been demonstrated to mediate neuroprotection. This effect of EPO may in part rely on a beneficial effect on cerebrovascular dysfunction leading to ischaemic neuronal damage. We investigated the in vivo effects of subcutaneously...... administered recombinant EPO on impaired cerebral blood flow (CBF) autoregulation after experimental subarachnoid haemorrhage (SAH). Four groups of male Sprague-Dawley rats were studied: group A, sham operation plus vehicle; group B, sham operation plus EPO; group C, SAH plus vehicle; group D, SAH plus EPO....... SAH was induced by injection of 0.07 ml of autologous blood into the cisterna magna. EPO (400 iu kg(-1) s.c.) or vehicle was given immediately after the subarachnoid injection of blood or saline. Forty-eight hours after the induction of SAH, CBF autoregulatory function was evaluated using...

  11. The partial coherence method for assessment of impaired cerebral autoregulation using near-infrared spectroscopy: potential and limitations.

    Science.gov (United States)

    De Smet, D; Jacobs, J; Ameye, L; Vanderhaegen, J; Naulaers, G; Lemmers, P; van Bel, F; Wolf, M; Van Huffel, S

    2010-01-01

    The most important forms of brain injury in premature infants are partly caused by disturbances in cerebral autoregulation. As changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO(2)), and cerebral tissue oxygenation (TOI) reflect changes in cerebral blood flow (CBF), impaired autoregulation can be measured by studying the concordance between HbD/rSO(2)/TOI and the mean arterial blood pressure (MABP), assuming no changes in oxygen consumption, arterial oxygen saturation (SaO(2)), and in blood volume. We investigated the performance of the partial coherence (PCOH) method, and compared it with the coherence method (COH). The PCOH method allows the elimination of the influence of SaO(2) on HbD/rSO(2)/TOI in a linear way. We started from long-term recordings measured in the first days of life simultaneously in 30 infants from three medical centres. We then compared the COH and PCOH results with patient clinical characteristics and outcomes, and concluded that PCOH might be a better method for assessing impaired autoregulation. PMID:20204795

  12. Dynamic cerebral autoregulatory capacity is affected early in Type 2 diabetes

    DEFF Research Database (Denmark)

    Kim, Y.S.; Immink, R.V.; Stok, W.J.;

    2008-01-01

    ) and impaired in subjects with DM+ (30+/-5 degrees ; Pblood pressure oscillations by affected dynamic cerebral autoregulation. The steady-state response of MCA V(mean) to postural change was comparable for all groups (-12+/-6% in CTRL subjects......, -15+/-6% in subjects with DM- and -15+/-7% in subjects with DM+). HbA(1c) (glycated haemoglobin) and the duration of diabetes, but not blood pressure, were determinants of transfer function phase. In conclusion, dysfunction of dynamic cerebral autoregulation in subjects with Type 2 diabetes appears......Type 2 diabetes is associated with an increased risk of endothelial dysfunction and microvascular complications with impaired autoregulation of tissue perfusion. Both microvascular disease and cardiovascular autonomic neuropathy may affect cerebral autoregulation. In the present study, we tested...

  13. How measurement artifacts affect cerebral autoregulation outcomes: A technical note on transfer function analysis.

    Science.gov (United States)

    Meel-van den Abeelen, Aisha S S; de Jong, Daan L K; Lagro, Joep; Panerai, Ronney B; Claassen, Jurgen A H R

    2016-05-01

    Cerebral autoregulation (CA) is the mechanism that aims to maintain adequate cerebral perfusion during changes in blood pressure (BP). Transfer function analysis (TFA), the most reported method in literature to quantify CA, shows large between-study variability in outcomes. The aim of this study is to investigate the role of measurement artifacts in this variation. Specifically, the role of distortion in the BP and/or CBFV measurementon TFA outcomes was investigated. The influence of three types of artifacts on TFA outcomes was studied: loss of signal, motion artifacts, and baseline drifts. TFA metrics of signals without the simulated artifacts were compared with those of signals with artifacts. TFA outcomes scattered highly when more than 10% of BP signal or over 8% of the CBFV signal was lost, or when measurements contained one or more artifacts resulting from head movement. Furthermore, baseline drift affected interpretation of TFA outcomes when the power in the BP signal was 5 times the power in the LF band. In conclusion, loss of signal in BP and loss in CBFV, affects interpretation of TFA outcomes. Therefore, it is vital to validate signal quality to the defined standards before interpreting TFA outcomes. PMID:26935320

  14. Nonlinear analysis of renal autoregulation in rats using principal dynamic modes

    DEFF Research Database (Denmark)

    Marmarelis, V Z; Chon, K H; Holstein-Rathlou, N H;

    1999-01-01

    This article presents results of the use of a novel methodology employing principal dynamic modes (PDM) for modeling the nonlinear dynamics of renal autoregulation in rats. The analyzed experimental data are broadband (0-0.5 Hz) blood pressure-flow data generated by pseudorandom forcing and colle...

  15. Closed-Loop Dynamic Modeling of Cerebral Hemodynamics

    Science.gov (United States)

    Marmarelis, V. Z.; Shin, D. C.; Orme, M. E.; Zhang, R.

    2013-01-01

    The dynamics of cerebral hemodynamics have been studied extensively because of their fundamental physiological and clinical importance. In particular, the dynamic processes of cerebral flow autoregulation and CO2 vasomotor reactivity have attracted broad attention because of their involvement in a host of pathologies and clinical conditions (e.g. hypertension, syncope, stroke, traumatic brain injury, vascular dementia, Alzheimer’s disease, mild cognitive impairment etc.). This raises the prospect of useful diagnostic methods being developed on the basis of quantitative models of cerebral hemodynamics, if cerebral vascular dysfunction can be quantified reliably from data collected within practical clinical constraints. This paper presents a modeling method that utilizes beat-to-beat measurements of mean arterial blood pressure, cerebral blood flow velocity and end-tidal CO2 (collected non-invasively under resting conditions) to quantify the dynamics of cerebral flow autoregulation (CFA) and cerebral vasomotor reactivity (CVMR). The unique and novel aspect of this dynamic model is that it is nonlinear and operates in a closed-loop configuration. PMID:23292615

  16. Chronically impaired autoregulation of cerebral blood flow in long-term diabetics

    DEFF Research Database (Denmark)

    Bentsen, N; Larsen, B; Lassen, N A

    1975-01-01

    of the patient. Regression analysis was carried out on the results in order to quantify autoregulatory capacity. In the control patients CBF did not vary with moderate blood pressure variations, indicating normal autoregulation. In four of the 16 diabetic patients CBF showed significant pressure dependency...

  17. Dynamic cerebral autoregulatory capacity is affected early in type 2 diabetes mellitus

    OpenAIRE

    Kim, Yu-Sok; Immink, Rogier V.; Stok, Wim J.; Karemaker, John M.; Secher, Niels H; van Lieshout, Johannes J.

    2008-01-01

    Abstract Type 2 diabetes is associated with an increased risk of endothelial dysfunction and microvascular complications with impaired autoregulation of tissue perfusion. Both microvascular disease and cardiovascular autonomic neuropathy may affect cerebral autoregulation. We tested the hypothesis that in absence of cardiovascular autonomic neuropathy, cerebral autoregulation is impaired in subjects with type 2 diabetes with microvascular complications but intact in subjects withou...

  18. Cerebral autoregulation in the preterm newborn using near-infrared spectroscopy: a comparison of time-domain and frequency-domain analyses

    Science.gov (United States)

    Eriksen, Vibeke R.; Hahn, Gitte H.; Greisen, Gorm

    2015-03-01

    The aim was to compare two conventional methods used to describe cerebral autoregulation (CA): frequency-domain analysis and time-domain analysis. We measured cerebral oxygenation (as a surrogate for cerebral blood flow) and mean arterial blood pressure (MAP) in 60 preterm infants. In the frequency domain, outcome variables were coherence and gain, whereas the cerebral oximetry index (COx) and the regression coefficient were the outcome variables in the time domain. Correlation between coherence and COx was poor. The disagreement between the two methods was due to the MAP and cerebral oxygenation signals being in counterphase in three cases. High gain and high coherence may arise spuriously when cerebral oxygenation decreases as MAP increases; hence, time-domain analysis appears to be a more robust-and simpler-method to describe CA.

  19. Upper limit of cerebral blood flow autoregulation in experimental renovascular hypertension in the baboon

    DEFF Research Database (Denmark)

    Strandgaard, S; Jones, J V; MacKenzie, E T;

    1975-01-01

    The effect of arterial hypertension on cerebral blood flow was studied by the intracarotid 133Xe clearance method in baboons. The arterial blood pressure was raised in gradual steps with angiotensin. Baboons with renal hypertension of 8-12 weeks duration were studied along with normotensive baboons....... In initially normotensive baboons, cerebral blood flow remained constant until the mean arterial blood pressure had risen to the range of 140 to 154 mm Hg; thereafter cerebral blood flow increased with each rise in mean arterial blood pressure. In the chronically hypertensive baboons, cerebral blood flow...... remained constant until the mean arterial blood pressure had been elevated to the range of 155 to 169 mm Hg. Thus, in chronic hypertension it appears that there are adaptive changes in the cerebral circulation which may help to protect the brain from further increases in arterial blood pressure....

  20. Laser Doppler flowmetry is valid for measurement of cerebral blood flow autoregulation lower limit in rats

    DEFF Research Database (Denmark)

    Tonnesen, Jan; Pryds, Anders; Larsen, Erik Hviid;

    2005-01-01

    was challenged by controlled systemic haemorrhage, or (2) cerebral blood flow was varied by manipulating the arterial partial pressure of CO2 (Pa,CO2). LDF slightly overestimated CBF under conditions of haemorrhagic shock and haemodilution caused by controlled haemorrhage (paired t test, P

  1. Impaired autoregulation of cerebral blood flow in long-term type I (insulin-dependent) diabetic patients with nephropathy and retinopathy

    DEFF Research Database (Denmark)

    Kastrup, J; Rørsgaard, S; Parving, H H;

    1986-01-01

    . Cerebral blood flow was measured by the intravenous 133Xenon method. Mean arterial blood pressure was elevated approximately 30 mmHg by intravenous infusion of angiotensin amide II and lowered about 10 mmHg by intravenous infusion of trimethaphan camsylate. In the control subjects the flow/pressure curve...... was horizontal indicating perfect autoregulation. In the diabetic patients the flow/pressure curve showed a significant slope with a 1.9% change in CBF per 10 mmHg change in mean arterial blood pressure as compared to a slope value of -0.4% in the control subjects (P less than 0.05). Our results confirm...

  2. Bradykinin antagonist counteracts the acute effect of both angiotensin-converting enzyme inhibition and of angiotensin receptor blockade on the lower limit of autoregulation of cerebral blood flow

    DEFF Research Database (Denmark)

    Sigurdsson, Sigurdur T; Paulson, Olaf B; Høj Nielsen, Arne;

    2014-01-01

    The lower limit of autoregulation of cerebral blood flow (CBF) can be modulated with both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB). The influence of bradykinin antagonism on ARB-induced changes was the subject of this study. CBF was measured in Sprague......-Dawley rats with laser Doppler technique. The blood pressure was lowered by controlled bleeding. Six groups of rats were studied: a control group and five groups given drugs intravenously: an ACE inhibitor (enalaprilat), an ARB (candesartan), a bradykinin-2 receptor antagonist (Hoe 140), a combination...

  3. Continuous assessment of cerebral autoregulation by TCD during tilt table testing

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Yuan; Imre Szirmai; Robert Debreczeni

    2006-01-01

    TTTT is a non-invasive and new investigative examination, and a most important method of clinical diagnosis for many diseases, specially for orthostatic syncope, autonomic failure, intracranial hypertension, neurodegenerative diseases, CVAs and so on. At the same time, TCD technique for non-invasive monitoring of CBFV has also provided a new tool for investigating CA. In clinical circumstance, we may carry on assessment of dynamic CA by TTTT, and this kind of method has been proved to be appropriate to examine patients and monitor. we can choose different tilt positions by tilt-table according to the different demands for clinical diagnosis or researches, and record the different appearances of various index signs, we can take advantage of the technique of transfer function analysis of power spectrum between spontaneous changes in CBF and other factors (such as arterial pressure) to do research on the specific mechanism of impaired CA.

  4. Vortex Dynamics in Cerebral Aneurysms

    CERN Document Server

    Byrne, Greg

    2013-01-01

    We use an autonomous three-dimensional dynamical system to study embedded vortex structures that are observed to form in computational fluid dynamic simulations of patient-specific cerebral aneurysm geometries. These structures, described by a vortex which is enclosed within a larger vortex flowing in the opposite direction, are created and destroyed in phase space as fixed points undergo saddle-node bifurcations along vortex core lines. We illustrate how saddle-node bifurcations along vortex core lines also govern the formation and evolution of embedded vortices in cerebral aneurysms under variable inflow rates during the cardiac cycle.

  5. Zinc-Finger Nuclease Knockout of Dual-Specificity Protein Phosphatase-5 Enhances the Myogenic Response and Autoregulation of Cerebral Blood Flow in FHH.1BN Rats

    Science.gov (United States)

    Fan, Fan; Geurts, Aron M.; Pabbidi, Mallikarjuna R.; Smith, Stanley V.; Harder, David R.; Jacob, Howard; Roman, Richard J.

    2014-01-01

    We recently reported that the myogenic responses of the renal afferent arteriole (Af-Art) and middle cerebral artery (MCA) and autoregulation of renal and cerebral blood flow (RBF and CBF) were impaired in Fawn Hooded hypertensive (FHH) rats and were restored in a FHH.1BN congenic strain in which a small segment of chromosome 1 from the Brown Norway (BN) containing 15 genes including dual-specificity protein phosphatase-5 (Dusp5) were transferred into the FHH genetic background. We identified 4 single nucleotide polymorphisms in the Dusp5 gene in FHH as compared with BN rats, two of which altered CpG sites and another that caused a G155R mutation. To determine whether Dusp5 contributes to the impaired myogenic response in FHH rats, we created a Dusp5 knockout (KO) rat in the FHH.1BN genetic background using a zinc-finger nuclease that introduced an 11 bp frame-shift deletion and a premature stop codon at AA121. The expression of Dusp5 was decreased and the levels of its substrates, phosphorylated ERK1/2 (p-ERK1/2), were enhanced in the KO rats. The diameter of the MCA decreased to a greater extent in Dusp5 KO rats than in FHH.1BN and FHH rats when the perfusion pressure was increased from 40 to 140 mmHg. CBF increased markedly in FHH rats when MAP was increased from 100 to 160 mmHg, and CBF was better autoregulated in the Dusp5 KO and FHH.1BN rats. The expression of Dusp5 was higher at the mRNA level but not at the protein level and the levels of p-ERK1/2 and p-PKC were lower in cerebral microvessels and brain tissue isolated from FHH than in FHH.1BN rats. These results indicate that Dusp5 modulates myogenic reactivity in the cerebral circulation and support the view that a mutation in Dusp5 may enhance Dusp5 activity and contribute to the impaired myogenic response in FHH rats. PMID:25397684

  6. Zinc-finger nuclease knockout of dual-specificity protein phosphatase-5 enhances the myogenic response and autoregulation of cerebral blood flow in FHH.1BN rats.

    Directory of Open Access Journals (Sweden)

    Fan Fan

    Full Text Available We recently reported that the myogenic responses of the renal afferent arteriole (Af-Art and middle cerebral artery (MCA and autoregulation of renal and cerebral blood flow (RBF and CBF were impaired in Fawn Hooded hypertensive (FHH rats and were restored in a FHH.1BN congenic strain in which a small segment of chromosome 1 from the Brown Norway (BN containing 15 genes including dual-specificity protein phosphatase-5 (Dusp5 were transferred into the FHH genetic background. We identified 4 single nucleotide polymorphisms in the Dusp5 gene in FHH as compared with BN rats, two of which altered CpG sites and another that caused a G155R mutation. To determine whether Dusp5 contributes to the impaired myogenic response in FHH rats, we created a Dusp5 knockout (KO rat in the FHH.1BN genetic background using a zinc-finger nuclease that introduced an 11 bp frame-shift deletion and a premature stop codon at AA121. The expression of Dusp5 was decreased and the levels of its substrates, phosphorylated ERK1/2 (p-ERK1/2, were enhanced in the KO rats. The diameter of the MCA decreased to a greater extent in Dusp5 KO rats than in FHH.1BN and FHH rats when the perfusion pressure was increased from 40 to 140 mmHg. CBF increased markedly in FHH rats when MAP was increased from 100 to 160 mmHg, and CBF was better autoregulated in the Dusp5 KO and FHH.1BN rats. The expression of Dusp5 was higher at the mRNA level but not at the protein level and the levels of p-ERK1/2 and p-PKC were lower in cerebral microvessels and brain tissue isolated from FHH than in FHH.1BN rats. These results indicate that Dusp5 modulates myogenic reactivity in the cerebral circulation and support the view that a mutation in Dusp5 may enhance Dusp5 activity and contribute to the impaired myogenic response in FHH rats.

  7. T2’-Imaging to Assess Cerebral Oxygen Extraction Fraction in Carotid Occlusive Disease: Influence of Cerebral Autoregulation and Cerebral Blood Volume

    Science.gov (United States)

    Deichmann, Ralf; Pfeilschifter, Waltraud; Hattingen, Elke; Singer, Oliver C.; Wagner, Marlies

    2016-01-01

    Purpose Quantitative T2'-mapping detects regional changes of the relation of oxygenated and deoxygenated hemoglobin (Hb) by using their different magnetic properties in gradient echo imaging and might therefore be a surrogate marker of increased oxygen extraction fraction (OEF) in cerebral hypoperfusion. Since elevations of cerebral blood volume (CBV) with consecutive accumulation of Hb might also increase the fraction of deoxygenated Hb and, through this, decrease the T2’-values in these patients we evaluated the relationship between T2’-values and CBV in patients with unilateral high-grade large-artery stenosis. Materials and Methods Data from 16 patients (13 male, 3 female; mean age 53 years) with unilateral symptomatic or asymptomatic high-grade internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis/occlusion were analyzed. MRI included perfusion-weighted imaging and high-resolution T2’-mapping. Representative relative (r)CBV-values were analyzed in areas of decreased T2’ with different degrees of perfusion delay and compared to corresponding contralateral areas. Results No significant elevations in cerebral rCBV were detected within areas with significantly decreased T2’-values. In contrast, rCBV was significantly decreased (pperfusion delay and decreased T2’. Furthermore, no significant correlation between T2’- and rCBV-values was found. Conclusions rCBV is not significantly increased in areas of decreased T2’ and in areas of restricted perfusion in patients with unilateral high-grade stenosis. Therefore, T2’ should only be influenced by changes of oxygen metabolism, regarding our patient collective especially by an increase of the OEF. T2’-mapping is suitable to detect altered oxygen consumption in chronic cerebrovascular disease. PMID:27560515

  8. High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure

    DEFF Research Database (Denmark)

    Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth;

    2014-01-01

    This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without...... increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature....... adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic...

  9. Cerebral autoregulation and flow/metabolism coupling during cardiopulmonary bypass: the influence of PaCO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Murkin, J.M.; Farrar, J.K.; Tweed, W.A.; McKenzie, F.N.; Guiraudon, G.

    1987-09-01

    Measurement of /sup 133/Xe clearance and effluent cerebral venous blood sampling were used in 38 patients to determine the effects of cardiopulmonary bypass, and of maintaining temperature corrected or noncorrected PaCO/sub 2/ at 40 mm Hg on regulation of cerebral blood flow (CBF) and flow/metabolism coupling. After induction of anesthesia with diazepam and fentanyl, mean CBF was 25 ml X 100 g-1 X min-1 and cerebral oxygen consumption, 1.67 ml X 100 g-1 X min-1. Cerebral oxygen consumption during nonpulsatile cardiopulmonary bypass at 26 degrees C was reduced to 0.42 ml X 100 g-1 X min-1 in both groups. CBF was reduced to 14-15 ml X 100 g-1 X min-1 in the non-temperature-corrected group (n = 21), was independent of cerebral perfusion pressure over the range of 20-100 mm Hg, but correlated with cerebral oxygen consumption. In the temperature-corrected group (n = 17), CBF varied from 22 to 32 ml X 100 g-1 X min-1, and flow/metabolism coupling was not maintained (i.e., CBF and cerebral oxygen consumption varied independently). However, variation in CBF correlated significantly with cerebral perfusion pressure over the pressure range of 15-95 mm Hg. This study demonstrates a profound reduction in cerebral oxygen consumption during hypothermic nonpulsatile cardiopulmonary bypass. When a non-temperature-corrected PaCO/sub 2/ of approximately 40 mm Hg was maintained, CBF was lower, and analysis of pooled data suggested that CBF regulation was better preserved, i.e., CBF was independent of pressure changes and dependent upon cerebral oxygen consumption.

  10. High-NaCl intake impairs dynamic autoregulation of renal blood flow in ANG II-infused rats

    DEFF Research Database (Denmark)

    Saeed, Aso; Dibona, Gerald F; Marcussen, Niels;

    2010-01-01

    The aim of this study was to investigate dynamic autoregulation of renal blood flow (RBF) in ANG II-infused rats and the influence of high-NaCl intake. Sprague-Dawley rats received ANG II (250 ng·kg(-1)·min(-1) sc) or saline vehicle (sham) for 14 days after which acute renal clearance experiments...... were performed during thiobutabarbital anesthesia. Rats (n = 8-10 per group) were either on a normal (NNa; 0.4% NaCl)- or high (HNa; 8% NaCl)-NaCl diet. Separate groups were treated with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (tempol; 1 M in drinking water). Transfer function analysis from...

  11. Applicability of near-infrared spectroscopy to measure cerebral autoregulation noninvasively in neonates: a validation study in piglets

    DEFF Research Database (Denmark)

    Holst Hahn, Gitte; Heiring, Christian; Pryds, Ole;

    2011-01-01

    , we compared NIRS-derived measures of CA with a conventional measure of CA: cerebral blood flow was measured by laser Doppler flowmetry, and changes in ABP were induced by inflating a thoracic aorta balloon. CA capacity was calculated as %¿CVR/%¿ABP (i.e. percentage of full autoregulatory capacity......), where CVR (i.e. cerebral vascular resistance) was estimated as ABP/Doppler flux. Correlation between coherence and CA capacity (r = -0.34, n = 24, p > 0.05) and between gain and CA capacity (r = -0.11, n = 24, p > 0.05) was limited. As expected, however, gain was significantly associated with CA...

  12. Applicability of near-infrared spectroscopy to measure cerebral autoregulation noninvasively in neonates: a validation study in piglets

    DEFF Research Database (Denmark)

    Holst Hahn, Gitte; Heiring, Christian; Pryds, Ole;

    2011-01-01

    , we compared NIRS-derived measures of CA with a conventional measure of CA: cerebral blood flow was measured by laser Doppler flowmetry, and changes in ABP were induced by inflating a thoracic aorta balloon. CA capacity was calculated as %ΔCVR/%ΔABP (i.e. percentage of full autoregulatory capacity......), where CVR (i.e. cerebral vascular resistance) was estimated as ABP/Doppler flux. Correlation between coherence and CA capacity (r = -0.34, n = 24, p > 0.05) and between gain and CA capacity (r = -0.11, n = 24, p > 0.05) was limited. As expected, however, gain was significantly associated with CA...

  13. Cerebrovascular hemodynamics in patients with cerebral arteriosclerosis

    Institute of Scientific and Technical Information of China (English)

    Jianbo Yang; Changcong Cui; Chengbin Wu

    2011-01-01

    The present study observed hemodynamic changes in 26 patients with cerebral arteriosclerosis using a cerebral circulation dynamics detector and transcranial Doppler.In patients with cerebral arteriosclerosis the blood supply and flow rate in the bilateral carotid arteries and the blood flow rate in the anterior cerebral and middle cerebral arteries were similar to normal controls, but the cerebral vascular resistance, critical pressure and pulsatility index were increased, and cerebral arterial elasticity and cerebral blood flow autoregulation were decreased.Compared with the lesioned hemisphere of patients with cerebral infarction, the total blood supply and blood flow rate of patients with cerebral arteriosclerosis were higher.Compared with normal subjects, patients with cerebral arteriosclerosis exhibited cognitive disturbances, mainly in short-term memory, attention, abstract capability, and spatial and executive dysfunction.Results showed that cerebral arteriosclerosis does not directly affect the blood supply of a cerebral hemisphere, but affects cognitive function.The increased cerebral vascular resistance and reduced autoregulation of cerebral blood vessels may be important hemodynamic mechanisms of arteriosclerosis-induced cerebral infarction.

  14. To autoregulate or not to autoregulate--that is no longer the question

    DEFF Research Database (Denmark)

    Greisen, Gorm

    2009-01-01

    in survivors. The analogy was hypertensive hemorrhagic stroke in the adult. Cerebral hemorrhage was perceived as the major (preventable) cause of brain injury in the preterm baby. An immature cerebral autoregulation or a vulnerability of the autoregulation exposed by preceding hypoxia or ischemia therefore...... became a focus of neonatal brain research in the 1980s. Over the years the focus has changed, first to the pathogenesis of hypoxic-ischemic brain injury, then to the effects of pCO(2), and now 30 years later to a more comprehensive, less clearly hypothesis-driven exploration of the multitude of factors......In the late 1970s, high cerebral blood flow was perceived as a cause of intracranial hemorrhage in the preterm infant. Intracranial hemorrhage was diagnosed by computed tomography and ultrasound found to be frequent not only in babies who died. Hemorrhage was soon linked to cerebral palsy...

  15. Cerebral hemodynamics after short- and long-term reduction in blood pressure in mild and moderate hypertension.

    NARCIS (Netherlands)

    Zhang, R.; Witkowski, S.; Fu, Q.; Claassen, J.A.H.R.; Levine, B.D.

    2007-01-01

    This study tested the hypothesis that acute reduction in blood pressure (BP) at the initial stage of antihypertensive therapy compromises brain perfusion and dynamic cerebral autoregulation in patients with hypertension. Cerebral blood flow velocity and BP were measured in patients with mild and mod

  16. Dynamic exercise enhances regional cerebral artery mean flow velocity

    DEFF Research Database (Denmark)

    Linkis, P; Jørgensen, L G; Olesen, H L;

    1995-01-01

    Dynamic exercise enhances regional cerebral artery mean flow velocity. J. Appl. Physiol. 78(1): 12-16, 1995.--Anterior (ACA) and middle (MCA) cerebral artery mean flow velocities (Vmean) and pulsatility indexes were determined using transcranial Doppler in 14 subjects during dynamic exercise afte...

  17. Regional cerebral blood flow alterations remote from the site of intracranial tumors

    DEFF Research Database (Denmark)

    Endo, H; Larsen, B; Lassen, N A

    1977-01-01

    Regional cerebral blood flow (rCBF) was investigated in 12 patients with brain tumors, using a 254-channel dynamic gamma camera. In nine of the 12 cases, hyperemic regions with loss of autoregulation were seen in sites remote from the tumor (the area around the tumor was in most cases also...

  18. Autoregulation of brain circulation in severe arterial hypertension

    DEFF Research Database (Denmark)

    Strandgaard, S; Olesen, Jes; Skinhoj, E;

    1973-01-01

    Cerebral blood flow was studied by the arteriovenous oxygen difference method in patients with severe hypertension and in normotensive controls. The blood pressure was lowered to study the lower limit of autoregulation (the pressure below which cerebral blood flow decreases) and the pressure limit...... of brain hypoxia. Both limits were shifted upwards in the hypertensive patients, probably as a consequence of hypertrophy of the arteriolar walls. These findings have practical implications for antihypertensive therapy.When the blood pressure was raised some patients showed an upper limit of...... autoregulation beyond which an increase of cerebral blood flow above the resting value was seen without clinical symptoms. No evidence of vasospasm was found in any patient at high blood pressure. These observations may be of importance for the understanding of the pathogenesis of hypertensive encephalopathy....

  19. Transient influence of end-tidal carbon dioxide tension on the postural restraint in cerebral perfusion

    DEFF Research Database (Denmark)

    Immink, R.V.; Truijen, J.; Secher, Niels H.;

    2009-01-01

    In the upright position, cerebral blood flow is reduced, maybe because arterial carbon dioxide partial pressure (Pa(CO(2))) decreases. We evaluated the time-dependent influence of a reduction in Pa(CO(2)), as indicated by the end-tidal Pco(2) tension (Pet(CO(2))), on cerebral perfusion during head......-up tilt. Mean arterial pressure, cardiac output, middle cerebral artery mean flow velocity (MCA V(mean)), and dynamic cerebral autoregulation at supine rest and 70 degrees head-up tilt were determined during free breathing and with Pet(CO(2)) clamped to the supine level. The postural changes in central...

  20. Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise

    DEFF Research Database (Denmark)

    Madsen, P L; Sperling, B K; Warming, T;

    1993-01-01

    Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions....... To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity...... in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P

  1. Dynamic touch is affected in children with cerebral palsy.

    Science.gov (United States)

    Ocarino, Juliana M; Fonseca, Sergio T; Silva, Paula L P; Gonçalves, Gabriela G P; Souza, Thales R; Mancini, Marisa C

    2014-02-01

    Children with developmental disorders such as cerebral palsy have limited opportunities for effortful interactions with objects and tools. The goal of the study was to investigate whether children with cerebral palsy have deficits in their ability to perceive object length by dynamic touch when compared to typically developing children. Fourteen children with typical development and 12 children with cerebral palsy were asked to report the length of hand-held rods after wielding them out of sight. Multilevel regression models indicated that I1 (maximum principal moment of inertia) was a significant predictor of perceived length - LP (pcerebral palsy (group factor) partially explained such variance (p=.002). In addition, accuracy and reliability of the length judgments made by children with cerebral palsy were significantly lower than the typically developing children (p<.05). Theoretical and clinical implications of these results were identified and discussed.

  2. Nonlinear Analysis of Renal Autoregulation Under Broadband Forcing Conditions

    DEFF Research Database (Denmark)

    Marmarelis, V Z; Chon, K H; Chen, Y M;

    1994-01-01

    Linear analysis of renal blood flow fluctuations, induced experimentally in rats by broad-band (pseudorandom) arterial blood pressure forcing at various power levels, has been unable to explain fully the dynamics of renal autoregulation at low frequencies. This observation has suggested the possi...

  3. Mechanisms regulating regional cerebral activation during dynamic handgrip in humans

    DEFF Research Database (Denmark)

    Williamson, James; Friedman, D B; Mitchell, J H;

    1996-01-01

    type of afferent input required for this cerebral activation. The rCBF was measured at +5.0 and +9.0 cm above the orbitomeatal (OM) plane in 13 subjects during 1) rest; 2) dynamic left-hand contractions; 3) postcontraction ischemia (metaboreceptor afferents); and 4) biceps brachii tendon vibration...

  4. Non-invasive assessment of cerebral microcirculation with diffuse optics and coherent hemodynamics spectroscopy

    Science.gov (United States)

    Fantini, Sergio; Sassaroli, Angelo; Kainerstorfer, Jana M.; Tgavalekos, Kristen T.; Zang, Xuan

    2016-03-01

    We describe the general principles and initial results of coherent hemodynamics spectroscopy (CHS), which is a new technique for the quantitative assessment of cerebral hemodynamics on the basis of dynamic near-infrared spectroscopy (NIRS) measurements. The two components of CHS are (1) dynamic measurements of coherent cerebral hemodynamics in the form of oscillations at multiple frequencies (frequency domain) or temporal transients (time domain), and (2) their quantitative analysis with a dynamic mathematical model that relates the concentration and oxygen saturation of hemoglobin in tissue to cerebral blood volume (CBV), cerebral blood flow (CBF), and cerebral metabolic rate of oxygen (CMRO2). In particular, CHS can provide absolute measurements and dynamic monitoring of CBF, and quantitative measures of cerebral autoregulation. We report initial results of CBF measurements in hemodialysis patients, where we found a lower CBF (54 +/- 16 ml/(100 g-min)) compared to a group of healthy controls (95 +/- 11 ml/(100 g-min)). We also report CHS measurements of cerebral autoregulation, where a quantitative index of autoregulation (its cutoff frequency) was found to be significantly greater in healthy subjects during hyperventilation (0.034 +/- 0.005 Hz) than during normal breathing (0.017 +/- 0.002 Hz). We also present our approach to depth resolved CHS, based on multi-distance, frequency-domain NIRS data and a two-layer diffusion model, to enhance sensitivity to cerebral tissue. CHS offers a potentially powerful approach to the quantitative assessment and continuous monitoring of local brain perfusion at the microcirculation level, with prospective brain mapping capabilities of research and clinical significance.

  5. Cerebral venous outflow and cerebrospinal fluid dynamics

    Directory of Open Access Journals (Sweden)

    Clive B. Beggs

    2014-12-01

    Full Text Available In this review, the impact of restricted cerebral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorption of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constricted venous outflow appears to be linked with increased aqueductal CSF pulsatility, it suggests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

  6. Cerebral vascular effects of hypovolemia and dopamine infusions

    DEFF Research Database (Denmark)

    Holst Hahn, Gitte; Heiring, Christian; Pryds, Ole;

    2012-01-01

    Despite widespread use, effects of volume boluses and dopamine in hypotensive newborn infants remain controversial. We aimed to elucidate if hypovolemia alone impairs cerebral autoregulation (CA) and if dopamine affects cerebral vasculature.......Despite widespread use, effects of volume boluses and dopamine in hypotensive newborn infants remain controversial. We aimed to elucidate if hypovolemia alone impairs cerebral autoregulation (CA) and if dopamine affects cerebral vasculature....

  7. Heterogeneous cerebral vasoreactivity dynamics in patients with carotid stenosis.

    Directory of Open Access Journals (Sweden)

    Ting-Yu Chang

    Full Text Available Cerebral vasoreactivity (CVR can be assessed by functional MRI (fMRI using hypercapnia challenges. In normal subjects, studies have shown temporal variability of CVR blood oxygenation level-dependent responses among different brain regions. In the current study, we analyzed the variability of BOLD CVR dynamics by fMRI with a breath-holding task in 17 subjects with unilateral carotid stenosis before they received carotid stenting. Great heterogeneity of CVR dynamics was observed when comparing BOLD responses between ipsilateral and contralateral hemispheres in each patient, especially in middle cerebral artery (MCA territories. While some subjects (n=12 had similar CVR responses between either hemisphere, the others (n=5 had a poorly correlated pattern of BOLD changes between ipsilateral and contralateral hemispheres. In the latter group, defined as impaired CVR, post-stenting perfusion tended to be more significantly increased. Our data provides the first observation of divergent temporal BOLD responses during breath holding in patients with carotid stenosis. The development of collateral circulation and the derangement of cerebral hemodynamics can be detected through this novel analysis of the different patterns of BOLD changes. The results also help in prediction of robust increase of perfusion or hyperperfusion after carotid stenting.

  8. Personal computer aided cerebral perfusion imaging with dynamic CT

    Institute of Scientific and Technical Information of China (English)

    林燕; 高培毅

    2004-01-01

    @@Reports on the clinical implementation of dynamic computerised tomography (CT) perfusion imaging and quantitative measurement have increased dramatically of late.1-8 The advantages of dynamic CT perfusion imaging and quantitative measurement for the diagnosis of acute cerebral infarction have been acknowledged. However, most overseas CT vendors set perfusion imaging software package as an option for graphic workstation at a too high price for domestic practitioners. To foster the domestic implementation and development of this new technology, we have extended the earlier work.1,2 Applying the theory of central volume principle to DICOM 3.0 standard forms of prime CT images, we developed dynamic CT perfusion imaging and quantitative measure-ment programmes for PCs using Visual C+ + in Windows 98 system.

  9. [Autoregulation in therapeutic effects].

    Science.gov (United States)

    Zilov, V G

    1996-01-01

    Self-regulation as the basic principle in the organization of living beings is analyzed from the viewpoint of the functional system theory for orthodox medicine and nonconventional therapies. Only some therapies in orthodox medicine are based on self-regulation whereas its role in nonconventional or traditional medicine is proposed to be more frequent and important. The paper describes how the similar principle can be clearly understood when the fundamental FST-principle (self-regulation) is used. The problems of the so-called vibrational medicine with its notion of a human being as a multidimensional organism made up of physical/cellular systems in a dynamic interplay with complex regulatory energy fields. Self-regulation is considered to be the crucial principle when subtle energetic medical approaches are applied as a cure. The paper also draws attention to informational processes in the body and its possible role in the mechanisms of orthodox and nonconventional therapies. The idea that the methods of traditional medicine have to be considered as complementary, but not alternative to orthodox, academic medicine is emphasized. PMID:9102075

  10. Between-centre variability in transfer function analysis, a widely used method for linear quantification of the dynamic pressure–flow relation: The CARNet study

    OpenAIRE

    Meel-van den Abeelen, Aisha S.S.; Simpson, David M.; Wang, Lotte J.Y.; Slump, Cornelis H; Zhang, Rong; Tarumi, Takashi; Rickards, Caroline A.; Payne, Stephen; Mitsis, Georgios D.; Kostoglou, Kyriaki; Marmarelis, Vasilis; Shin, Dae; Tzeng, Yu-Chieh; Ainslie, Philip N; Gommer, Erik

    2014-01-01

    Transfer function analysis (TFA) is a frequently used method to assess dynamic cerebral autoregulation (CA) using spontaneous oscillations in blood pressure (BP) and cerebral blood flow velocity (CBFV). However, controversies and variations exist in how research groups utilise TFA, causing high variability in interpretation. The objective of this study was to evaluate between-centre variability in TFA outcome metrics. 15 centres analysed the same 70 BP and CBFV datasets from healthy subjects ...

  11. Acute ischemic cerebral attack

    OpenAIRE

    Franco-Garcia Samir; Barreiro-Pinto Belis

    2010-01-01

    The decrease of the cerebral blood flow below the threshold of autoregulation led to changes of cerebral ischemia and necrosis that traduce in signs and symtoms of focal neurologic dysfunction called acute cerebrovascular symdrome (ACS) or stroke. Two big groups according to its etiology are included in this category the hemorragic that constitue a 20% and the ischemic a 80% of cases. Great interest has wom the ischemic ACS because of its high social burden, being the third cause of no violen...

  12. Time-varying modeling of cerebral hemodynamics.

    Science.gov (United States)

    Marmarelis, Vasilis Z; Shin, Dae C; Orme, Melissa; Rong Zhang

    2014-03-01

    The scientific and clinical importance of cerebral hemodynamics has generated considerable interest in their quantitative understanding via computational modeling. In particular, two aspects of cerebral hemodynamics, cerebral flow autoregulation (CFA) and CO2 vasomotor reactivity (CVR), have attracted much attention because they are implicated in many important clinical conditions and pathologies (orthostatic intolerance, syncope, hypertension, stroke, vascular dementia, mild cognitive impairment, Alzheimer's disease, and other neurodegenerative diseases with cerebrovascular components). Both CFA and CVR are dynamic physiological processes by which cerebral blood flow is regulated in response to fluctuations in cerebral perfusion pressure and blood CO2 tension. Several modeling studies to date have analyzed beat-to-beat hemodynamic data in order to advance our quantitative understanding of CFA-CVR dynamics. A confounding factor in these studies is the fact that the dynamics of the CFA-CVR processes appear to vary with time (i.e., changes in cerebrovascular characteristics) due to neural, endocrine, and metabolic effects. This paper seeks to address this issue by tracking the changes in linear time-invariant models obtained from short successive segments of data from ten healthy human subjects. The results suggest that systemic variations exist but have stationary statistics and, therefore, the use of time-invariant modeling yields "time-averaged models" of physiological and clinical utility.

  13. Spontaneous fluctuations in cerebral blood flow regulation: contribution of PaCO2.

    Science.gov (United States)

    Panerai, R B; Dineen, N E; Brodie, F G; Robinson, T G

    2010-12-01

    To investigate the temporal variability of dynamic cerebral autoregulation (CA), the transient response of cerebral blood flow to rapid changes in arterial blood pressure, a new approach was introduced to improve the temporal resolution of dynamic CA assessment. Continuous bilateral recordings of cerebral blood flow velocity (transcranial Doppler, middle cerebral artery), end-tidal Pco(2) (Pet(CO(2)), infrared capnograph), and blood pressure (Finapres) were obtained at rest and during breath hold in 30 young subjects (25 ± 6 yr old) and 30 older subjects (64 ± 4 yr old). Time-varying estimates of the autoregulation index [ARI(t)] were obtained with an autoregressive-moving average model with coefficients expanded by orthogonal decomposition. The temporal pattern of ARI(t) varied inversely with Pet(CO(2)), decreasing with hypercapnia. At rest, ARI(t) showed spontaneous fluctuations that were significantly different from noise and significantly correlated with spontaneous fluctuations in Pet(CO(2)) in the majority of recordings (young: 72% and old: 65%). No significant differences were found in ARI(t) due to aging. This new approach to improve the temporal resolution of dynamic CA parameters allows the identification of physiologically meaningful fluctuations in dynamic CA efficiency at rest and in response to changes in arterial CO(2). PMID:20884837

  14. Statins and cerebral hemodynamics

    Science.gov (United States)

    Giannopoulos, Sotirios; Katsanos, Aristeidis H; Tsivgoulis, Georgios; Marshall, Randolph S

    2012-01-01

    HMG-CoA reductase inhibitors (statins) are associated with improved stroke outcome. This observation has been attributed in part to the palliative effect of statins on cerebral hemodynamics and cerebral autoregulation (CA), which are mediated mainly through the upregulation of endothelium nitric oxide synthase (eNOS). Several animal studies indicate that statin pretreatment enhances cerebral blood flow after ischemic stroke, although this finding is not further supported in clinical settings. Cerebral vasomotor reactivity, however, is significantly improved after long-term statin administration in most patients with severe small vessel disease, aneurysmal subarachnoid hemorrhage, or impaired baseline CA. PMID:22929438

  15. Nonlinear system analysis of renal autoregulation in normotensive and hypertensive rats

    DEFF Research Database (Denmark)

    Chon, K H; Chen, Y M; Holstein-Rathlou, N H;

    1998-01-01

    We compared the dynamic characteristics in renal autoregulation of blood flow of normotensive Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR), using both linear and nonlinear systems analysis. Linear analysis yielded only limited information about the differences in dynamics b...

  16. Intensive blood pressure control affects cerebral blood flow in type 2 diabetes mellitus patients

    DEFF Research Database (Denmark)

    Kim, Yu-Sok; Davis, Shyrin C A T; Truijen, Jasper;

    2011-01-01

    Type 2 diabetes mellitus is associated with microvascular complications, hypertension, and impaired dynamic cerebral autoregulation. Intensive blood pressure (BP) control in hypertensive type 2 diabetic patients reduces their risk of stroke but may affect cerebral perfusion. Systemic hemodynamic...... variables and transcranial Doppler-determined cerebral blood flow velocity (CBFV), cerebral CO2 responsiveness, and cognitive function were determined after 3 and 6 months of intensive BP control in 17 type 2 diabetic patients with microvascular complications (T2DM+), in 18 diabetic patients without (T2DM......-) microvascular complications, and in 16 nondiabetic hypertensive patients. Cerebrovascular reserve capacity was lower in T2DM+ versus T2DM- and nondiabetic hypertensive patients (4.6±1.1 versus 6.0±1.6 [P

  17. Dynamic alteration of regional cerebral blood flow during carotid compression and proof of reversibility

    OpenAIRE

    Asahi, Kouichi; Hori, M; Hamasaki, N; Sato, S.; Nakanishi, H; Kuwatsuru, R; Sasai, K; Aoki, S.

    2012-01-01

    Background It is difficult to non-invasively visualize changes in regional cerebral blood flow caused by manual compression of the carotid artery. Purpose To visualize dynamic changes in regional cerebral blood flow during and after manual compression of the carotid artery. Material and Methods Two healthy volunteers were recruited. Anatomic features and flow directions in the circle of Willis were evaluated with time-of-flight magnetic resonance angiography (MRA) and two-dimensional phase-co...

  18. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  19. Ocular Blood Flow Autoregulation Mechanisms and Methods

    Directory of Open Access Journals (Sweden)

    Xue Luo

    2015-01-01

    Full Text Available The main function of ocular blood flow is to supply sufficient oxygen and nutrients to the eye. Local blood vessels resistance regulates overall blood distribution to the eye and can vary rapidly over time depending on ocular need. Under normal conditions, the relation between blood flow and perfusion pressure in the eye is autoregulated. Basically, autoregulation is a capacity to maintain a relatively constant level of blood flow in the presence of changes in ocular perfusion pressure and varied metabolic demand. In addition, ocular blood flow dysregulation has been demonstrated as an independent risk factor to many ocular diseases. For instance, ocular perfusion pressure plays key role in the progression of retinopathy such as glaucoma and diabetic retinopathy. In this review, different direct and indirect techniques to measure ocular blood flow and the effect of myogenic and neurogenic mechanisms on ocular blood flow are discussed. Moreover, ocular blood flow regulation in ocular disease will be described.

  20. The Algorithmic Autoregulation Software Development Methodology

    OpenAIRE

    Fabbri, Renato; Fabbri, Ricardo; Vieira, Vilson; Penalva, Daniel; Shiga, Danilo; Mendonca, Marcos; Negrao, Alexandre; Zambianchi, Lucas; Thume, Gabriela

    2016-01-01

    We present a new self-regulating methodology for coordinating distributed team work called Algorithmic Autoregulation (AA), based on recent social networking concepts and individual merit. Team members take on an egalitarian role, and stay voluntarily logged into so-called AA sessions for part of their time (e.g. 2 hours per day), during which they create periodical logs - short text sentences - they wish to share about their activity with the team. These logs are publicly aggregated in a web...

  1. Modulation of cerebral blood flow with transcutaneous electrical neurostimulation (TENS) in patients with cerebral vasospasm after subarachnoid hemorrhage

    NARCIS (Netherlands)

    ter Laan, Mark; van Dijk, J.M.C.; Stewart, Roy; Staal, Michiel J; Elting, Jan-Willem J

    2014-01-01

    ObjectivesTranscutaneous electrical neurostimulation (TENS) and spinal cord stimulation have been shown to increase peripheral and cerebral blood flow. We postulate that certain pathological conditions attenuate cerebral autoregulation, which may result in a relative increase of the importance of ne

  2. Effect of a Dynamic Seating Surface on Postural Control and Function in Children with Cerebral Palsy

    DEFF Research Database (Denmark)

    Meyer, Erna Rosenlund; Trew, Lisa

    Purpose: The purpose was to investigate if a seating system involving a dynamic material covering the seat back and base improves postural control, alignment and function in children with cerebral palsy and to investigate consequences of adapting The Seated Postural Control Measure to a target...

  3. Bimodal oscillations in nephron autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A N; Mosekilde, E;

    2002-01-01

    The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular ...

  4. Monitoring of cerebral haemodynamics in newborn infants

    DEFF Research Database (Denmark)

    Liem, K Djien; Greisen, Gorm

    2010-01-01

    The most important cerebrovascular injuries in newborn infants, particularly in preterm infants, are cerebral haemorrhage and ischemic injury. The typical cerebral vascular anatomy and the disturbance of cerebral haemodynamics play important roles in the pathophysiology. The term 'cerebral...... haemodynamics' includes cerebral blood flow (CBF), cerebral blood flow velocity, and cerebral blood volume (CBV). Therapy aimed at changing vascular anatomy is not available. Therefore, prevention of disturbances in CBF and CBV is pivotal. However, continuous monitoring of CBF and CBV is still unavailable for....... Using it even without knowing the exact level of CBF and CBV, it is possible to aim to keep CBF and CBV stable. Futureresearch should focus on development of monitoring tools, gaining more insight in neonatal cerebral autoregulation, and demonstrating clinical benefits of a 'cerebral perfusion...

  5. Autoregulating Jump Performance to Induce Functional Overreaching.

    Science.gov (United States)

    Claudino, João G; Cronin, John B; Mezêncio, Bruno; Pinho, João P; Pereira, Conrado; Mochizuki, Luis; Amadio, Alberto C; Serrão, Julio C

    2016-08-01

    Claudino, JG, Cronin, JB, Mezêncio, B, Pinho, JP, Pereira, C, Mochizuki, L, Amadio, AC, and Serrão, JC. Autoregulating jump performance to induce functional overreaching. J Strength Cond Res 30(8): 2242-2249, 2016-The purpose of this study was to determine whether autoregulating jump performance using the minimal individual difference (MID) associated with countermovement jump (CMJ) height could be used to regulate and monitor a training phase that elicited functional overreaching and tapering in team sport athletes. The participants were familiarized with the jump and then the CMJ height reliability was quantified to determine the MID. Countermovement jump height was assessed in the pretesting session (T0), at the end of 4 weeks of intensified training (T1), and after 2 weeks of tapering (T2). Eighteen national level U17 male futsal players were randomly allocated into the regulated group (RG; n = 9) and the control group (CG; n = 9). The RG performed 6 weeks of training with the training load regulated by mean height of CMJ with MID, whereas the CG performed the preplanned training. The differences between groups and across time points were compared by a 2-way analysis of variance. In the RG, the MID loading was increased in weeks 3 and 4 (8.2 and 14.5%, respectively; p jump results, the RG significantly (p ≤ 0.05) reduced CMJ height during T1 (effect size [ES] = -0.31; 95% confidence interval [CI]: -0.58 to -0.02); however, there were no significant changes in the CG jump height at T1 and T2. At T2, the RG significantly increased CMJ height above baseline (ES = 0.30; 95% CI: 0.09 to 0.51). Researchers and practitioners could use this autoregulating method to regulate and monitor training load to achieve functional overreaching in youth futsal players.

  6. Bimodal oscillations in nephron autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik;

    2002-01-01

    The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular...... feedback. We investigate the intra- and internephron entrainment of the two time scales. In addition to full synchronization, both wavelet analyses of experimental data and numerical simulations reveal a partial entrainment in which neighboring nephrons attain a state of chaotic synchronization...

  7. Study of the Dynamics of Transcephalic Cerebral Impedance Data during Cardio-Vascular Surgery

    Science.gov (United States)

    Atefi, S. R.; Seoane, F.; Lindecrantz, K.

    2013-04-01

    Postoperative neurological deficits are one of the risks associated with cardio vascular surgery, necessitating development of new techniques for cerebral monitoring. In this study an experimental observation regarding the dynamics of transcephalic Electrical Bioimpedance (EBI) in patients undergoing cardiac surgery with and without extracorporeal circulation (ECC) was conducted to investigate the potential use of electrical Bioimpedance for cerebral monitoring in cardio vascular surgery. Tetrapolar transcephalic EBI measurements at single frequency of 50 kHz were recorded prior to and during cardio vascular surgery. The obtained results show that the transcephalic impedance decreases in both groups of patients as operation starts, however slight differences in these two groups were also observed with the cerebral impedance reduction in patients having no ECC being less common and not as pronounced as in the ECC group. Changes in the cerebral impedance were in agreement with changes of haematocrit and temperature. The origin of EBI changes is still unexplained however these results encourage us to continue investigating the application of electrical bioimpedance cerebral monitoring clinically.

  8. Study of the Dynamics of Transcephalic Cerebral Impedance Data during Cardio-Vascular Surgery

    International Nuclear Information System (INIS)

    Postoperative neurological deficits are one of the risks associated with cardio vascular surgery, necessitating development of new techniques for cerebral monitoring. In this study an experimental observation regarding the dynamics of transcephalic Electrical Bioimpedance (EBI) in patients undergoing cardiac surgery with and without extracorporeal circulation (ECC) was conducted to investigate the potential use of electrical Bioimpedance for cerebral monitoring in cardio vascular surgery. Tetrapolar transcephalic EBI measurements at single frequency of 50 kHz were recorded prior to and during cardio vascular surgery. The obtained results show that the transcephalic impedance decreases in both groups of patients as operation starts, however slight differences in these two groups were also observed with the cerebral impedance reduction in patients having no ECC being less common and not as pronounced as in the ECC group. Changes in the cerebral impedance were in agreement with changes of haematocrit and temperature. The origin of EBI changes is still unexplained however these results encourage us to continue investigating the application of electrical bioimpedance cerebral monitoring clinically.

  9. A study for the correlation of hemorrhagic cerebral infarction with the hemodynamics measured by dynamic CT

    International Nuclear Information System (INIS)

    In 15 cases of cerebral infarction (9 embolisms, 6 thromboses), dynamic CT scans were repeatedly undertaken during 4 week period of stroke. The ratio of peak height to mean transit time (PH/MTT), which was calculated from density time curve, was used as an index of cerebral blood flow. Hemorrhagic infarction was defined as a high density area with CT value over 50 within low density area. The PH/MTT was significantly increased after the appearance of hemorrhagic infarction. Nine of 10 areas, in which hemorrhagic infarctions were not recognized after recoverry of PH/MTT to over 0.5, did not show hemorrhagic infarctions during 4 week period of stroke. The areas in which hemorrhagic infarctions appeared during 4 week period of stroke had mdore prolonged period of low PH/MTT values than the areas in which hemorrhagic infarctions were not recognized. In conclusion dynamic CT is useful for predicting hemorrhagic infarction. (author)

  10. Study for the correlation of hemorrhagic cerebral infarction with the hemodynamics measured by dynamic CT

    Energy Technology Data Exchange (ETDEWEB)

    Shibagaki, Yasuro (Tokyo Women' s Medical Coll. (Japan))

    1989-06-01

    In 15 cases of cerebral infarction (9 embolisms, 6 thromboses), dynamic CT scans were repeatedly undertaken during 4 week period of stroke. The ratio of peak height to mean transit time (PH/MTT), which was calculated from density time curve, was used as an index of cerebral blood flow. Hemorrhagic infarction was defined as a high density area with CT value over 50 within low density area. The PH/MTT was significantly increased after the appearance of hemorrhagic infarction. Nine of 10 areas, in which hemorrhagic infarctions were not recognized after recoverry of PH/MTT to over 0.5, did not show hemorrhagic infarctions during 4 week period of stroke. The areas in which hemorrhagic infarctions appeared during 4 week period of stroke had mdore prolonged period of low PH/MTT values than the areas in which hemorrhagic infarctions were not recognized. In conclusion dynamic CT is useful for predicting hemorrhagic infarction. (author).

  11. Model-based Quantification of Cerebral Hemodynamics as a Physiomarker for Alzheimer’s Disease?

    Science.gov (United States)

    Marmarelis, V. Z.; Shin, D. C.; Orme, M. E.; Zhang, R.

    2013-01-01

    Previous studies have found that Alzheimer’s disease (AD) impairs cerebral vascular function, even at early stages of the disease. This offers the prospect of a useful diagnostic method for AD, if cerebral vascular dysfunction can be quantified reliably within practical clinical constraints. We present a recently developed methodology that utilizes a data-based dynamic nonlinear closed-loop model of cerebral hemodynamics to compute “physiomarkers” quantifying the state of cerebral flow autoregulation to pressure-changes (CA) and cerebral CO2 vasomotor reactivity (CVMR) in each subject. This model is estimated from beat-to-beat measurements of mean arterial blood pressure, mean cerebral blood flow velocity and end-tidal CO2, which can be made reliably and non-invasively under resting conditions. This model may also take an open-loop form and comparisons are made with the closed-loop counterpart. The proposed model-based physiomarkers take the form of two indices that quantify the gain of the CA and CVMR processes in each subject. It was found in an initial set of clinical data that the CVMR index delineates AD patients from control subjects and, therefore, may prove useful in the improved diagnosis of early-stage AD. PMID:23771298

  12. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    INTRODUCTION: Clinical work on the blood perfusion in skin and muscle flaps has suggested that some degree of blood flow autoregulation exists in such flaps. An autoregulatory mechanism would enable the flap to protect itself from changes in the perfusion pressure. The purpose of the present study...... was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......-type calcium channel blocker nimodipine and the vasodilator papaverine. MATERIAL AND METHODS: Pedicled flaps were raised in pigs. Flow in the pedicle was reduced by constriction of the feed artery (n=34). A transit time flow probe measured the effect on blood flow continuously. Following this, three different...

  13. Renal autoregulation in medical therapy of renovascular hypertension

    OpenAIRE

    Lubas, Arkadiusz; Żelichowski, Grzegorz; Próchnicka, Agnieszka; Wiśniewska, Magdalena; Wańkowicz, Zofia

    2010-01-01

    Introduction Renovascular hypertension (RVH) is caused by renal ischaemia associated with haemodynamically significant renal artery stenosis (RAS). The choice of optimal treatment of atherosclerotic RAS is still controversial. Increase in the renal resistive index (RI) value after captopril administration is considered to indicate preserved renal autoregulation. The objective of the study was to assess the effect of medical therapy of RVH on renal autoregulation efficiency in patients with at...

  14. Effect of Vestibular Impairment on Cerebral Blood Flow Response to Dynamic Roll Tilt

    Science.gov (United States)

    Serrador, J. M.; Black, F. O.; Schlgel, Todd T.; Lipsitz, L. A.; Wood, S. J.

    2008-01-01

    Change to upright posture results in reductions in cerebral perfusion pressure due to hydrostatic pressure changes related to gravity. Since vestibular organs, specifically the otoliths, provide information on position relative to gravity, vestibular inputs may assist in adaptation to the upright posture. The goal of this study was to examine the effect of direct vestibular stimulation on cerebral blood flow (CBF). To examine the role of otolith inputs we screened 165 subjects for vestibular function and classified subjects as either normal or impaired based on ocular torsion. Ocular torsion, an indication of otolith function, was assessed during sinusoidal roll tilt of 20 degrees at 0.01 Hz (100 sec per cycle). Subjects with torsion one SD below the mean were classified as impaired while subjects one SD above the mean were considered normal. During one session subjects were placed in a chair that was sinusoidally rotated 25 degrees in the roll plane at five frequencies: 0.25 & 0.125 Hz for 80 sec, 0.0625 Hz for 160 sec and 0.03125 Hz and 0.015625 Hz for 320 sec. During testing, CBF (transcranial Doppler), blood pressure (Finapres), and end tidal CO2 (Puritan Bennet) were measured continuously. Ocular torsion was assessed from infrared images of the eyes. All rotations were done in the dark with subjects fixated on a red LED directly at the center of rotation. In the normal group, dynamic tilt resulted in significant changes in both blood pressure and cerebral blood flow velocity that was related to the frequency of stimulus. In contrast the impaired group did not show similar patterns. As expected normal subjects demonstrated significant ocular torsion that was related to stimulus frequency while impaired subjects had minimal changes. These data suggest that vestibular inputs have direct effects on cerebral blood flow regulation during dynamic tilt. Supported by NASA.

  15. Reconstruction of cerebral hemodynamics with dynamic contrast-enhanced time-resolved near-infrared measurements before and during ischemia

    Science.gov (United States)

    Elliott, Jonathan T.; Diop, Mamadou; Morrison, Laura B.; Lee, Ting-Yim; St. Lawrence, Keith

    2013-03-01

    We present a dynamic contrast-enhanced near-infrared (DCE-NIR) technique that is capable of non-invasive quantification of cerebral hemodynamics in adults. The challenge of removing extracerebral contamination is overcome through the use of multi-distance time-resolved DCE-NIR combined with the kinetic deconvolution optical reconstruction (KDOR) analytical method. As proof-of-principle, cerebral blood flow, cerebral blood volume and mean transit time recovered with DCE-NIR are compared with CT perfusion values in an adult pig during normocapnia, hypocapnia, and ischemia. Measurements of blood flow acquired with DCE-NIR were compared against concomitant measurements using CT Perfusion.

  16. COMPARISION OF DYNAMIC CYCLING VS STATIC CYCLING ON ENDURANCE, BALANCE, AND WALKING ABILITY OF CHILDREN WITH CEREBRAL PALSY

    OpenAIRE

    PatitapabanMohanty; Nishitha Meshram; Monalisa Pattnaik

    2015-01-01

    Background: The impairments in cerebral palsy can limit a child’s ability to play and exercise at intensities necessary to develop cardio respiratory fitness. Objective: To compare the effects of dynamic cycling, static cycling and conventional exercises in cardiovascular endurance, balance and walking ability in cerebral palsy children. Materials and Method: A total of 30 subjects were recruited in an experimental pre-post-test study design. Subjects were randomly assigned to 3 differe...

  17. Model-based physiomarkers of cerebral hemodynamics in patients with mild cognitive impairment.

    Science.gov (United States)

    Marmarelis, V Z; Shin, D C; Orme, M E; Zhang, R

    2014-05-01

    In our previous studies, we have introduced model-based "functional biomarkers" or "physiomarkers" of cerebral hemodynamics that hold promise for improved diagnosis of early-stage Alzheimer's disease (AD). The advocated methodology utilizes subject-specific data-based dynamic nonlinear models of cerebral hemodynamics to compute indices (serving as possible diagnostic physiomarkers) that quantify the state of cerebral blood flow autoregulation to pressure-changes (CFAP) and cerebral CO2 vasomotor reactivity (CVMR) in each subject. The model is estimated from beat-to-beat measurements of mean arterial blood pressure, mean cerebral blood flow velocity and end-tidal CO2, which can be made reliably and non-invasively under resting conditions. In a previous study, it was found that a CVMR index quantifying the impairment in CO2 vasomotor reactivity correlates with clinical indications of early AD, offering the prospect of a potentially useful diagnostic tool. In this paper, we explore the use of the same model-based indices for patients with amnestic Mild Cognitive Impairment (MCI), a preclinical stage of AD, relative to a control subjects and clinical cognitive assessments. It was found that the model-based CVMR values were lower for MCI patients relative to the control subjects.

  18. Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model

    International Nuclear Information System (INIS)

    Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.

  19. Information Processing in Auto-regulated Systems

    Directory of Open Access Journals (Sweden)

    Karl Javorszky

    2003-06-01

    Full Text Available Abstract: We present a model of information processing which is based on two concurrent ways of describing the world, where a description in one of the languages limits the possibilities for realisations in the other language. The two describing dimensions appear in our common sense as dichotomies of perspectives: subjective - objective; diversity - similarity; individual - collective. We abstract from the subjective connotations and treat the test theoretical case of an interval on which several concurrent categories can be introduced. We investigate multidimensional partitions as potential carriers of information and compare their efficiency to that of sequenced carriers. We regard the same assembly once as a contemporary collection, once as a longitudinal sequence and find promising inroads towards understanding information processing by auto-regulated systems. Information is understood to point out that what is the case from among alternatives, which could be the case. We have translated these ideas into logical operations on the set of natural numbers and have found two equivalence points on N where matches between sequential and commutative ways of presenting a state of the world can agree in a stable fashion: a flip-flop mechanism is envisioned. By following this new approach, a mathematical treatment of some poignant biomathematical problems is allowed. Also, the concepts presented in this treatise may well have relevance and applications within the information processing and the theory of language fields.

  20. Compromised cerebrovascular modulation in chronic anxiety: evidence from cerebral blood flow velocity measured by transcranial Doppler sonography

    Institute of Scientific and Technical Information of China (English)

    Hong-Liang Zhang; Zhen-Ni Guo; Ge Yang; Le Yang; Ke Han; Jiang Wu; Yingqi Xing; Yi Yang

    2012-01-01

    Objective Cerebral autoregulation (CA) is the mechanism by which constant cerebral blood flow is maintained despite changes in cerebral perfusion pressure.CA can be evaluated by dynamic monitoring of cerebral blood flow velocity (CBFV) with transcranial Doppler sonography (TCD).The present study aimed to explore CA in chronic anxiety.Methods Subjects with Hamilton anxiety scale scores ≥14 were enrolled and the dynamic changes of CBFV in response to an orthostatic challenge were investigated using TCD.Results In both the anxious and the healthy subjects,the mean CBFV was significantly lower in the upright position than when supine.However,the CBFV changes from supine to upright differed between the anxious and the healthy groups.Anxious subjects showed more pronounced decreases in CBFV with abrupt standing.Conclusion Our results indicate that cerebrovascular modulation is compromised in chronic anxiety; anxious subjects have some insufficiency in maintaining cerebral perfusion after postural change.Given the fact that anxiety and impaired CA are associated with cardiovascular disease,early ascertainment of compromised cerebrovascular modulation using TCD might suggest interventional therapies in the anxious population,and improve the primary prevention of cardiovascular disease.

  1. The Impacts of Spastic Cerebral Palsy Children on Dynamic Balance Performance

    Directory of Open Access Journals (Sweden)

    M.S. Saba

    2006-07-01

    Full Text Available Introduction & Objective: Despite of many studies on cerebral palsy (CP, the impacts of this disease on musculoskeletal function especially on the dynamic balance of the CP patients is not well understood. This information can improve the quality of the treatment. The objectives of this study were to evaluate the differences between the dynamic balance performance of normal and CP children in different conditions.Materials & Methods: Ten children with spastic diplegia cerebral palsy between 8 to15 years of age and with mean weight and height of 30.8±5.7kg and 1.35±0.09m respectively, underwent an exercise therapy program for 12 weeks. A stability platform system was used to measure the deviation on the mean point of the application of the center of gravity (COG from the center of base of support (COBOS. The balance tests were repeated on stable and unstable base of support as well as with and without shoes. Results: It was shown that the mean deviation of COG of the CP children improves about 25% after exercise therapy (p=0.001. The most improvement was in mid-stable and unstable of base of support as well as in AP direction. Mean deviations of COG was near to natural pattern Conclusion: The mean deviation of COG of the CP patients was significantly increased in dynamic standing which shows the poor function of the proprioceptive system in these children. Exercise therapy improves the mean deviation of COG in dynamic standing. These results show the importance of the shoes on the treatment procedures of the spastic CP children.

  2. Dynamic FDG PET for assessing early effects of cerebral hypoxia and resuscitation in new-born pigs

    International Nuclear Information System (INIS)

    Changes in cerebral glucose metabolism may be an early prognostic indicator of perinatal hypoxic-ischaemic injury. In this study dynamic 18F-FDG PET was used to evaluate cerebral glucose metabolism in piglets after global perinatal hypoxia and the impact of the resuscitation strategy using room air or hyperoxia. New-born piglets (n = 16) underwent 60 min of global hypoxia followed by 30 min of resuscitation with a fraction of inspired oxygen (FiO2) of 0.21 or 1.0. Dynamic FDG PET, using a microPET system, was performed at baseline and repeated at the end of resuscitation under stabilized haemodynamic conditions. MRI at 3 T was performed for anatomic correlation. Global and regional cerebral metabolic rates of glucose (CMRgl) were assessed by Patlak analysis for the two time-points and resuscitation groups. Global hypoxia was found to cause an immediate decrease in cerebral glucose metabolism from a baseline level (mean ± SD) of 21.2 ± 7.9 to 12.6 ± 4.7 μmol/min/100 g (p gl but no significant differences in global or regional CMRgl between the resuscitation groups were found. Dynamic FDG PET detected decreased cerebral glucose metabolism early after perinatal hypoxia in piglets. The decrease in CMRgl may indicate early changes of mild cerebral hypoxia-ischaemia. No significant effect of hyperoxic resuscitation on the degree of hypometabolism was found in this early phase after hypoxia. Cerebral FDG PET can provide new insights into mechanisms of perinatal hypoxic-ischaemic injury where early detection plays an important role in instituting therapy. (orig.)

  3. Dynamic Changes of the CT Perfusion Parameters in the Embolic Model of Cerebral Ischemia

    Institute of Scientific and Technical Information of China (English)

    陈唯唯; 漆剑频; 张进华; 黄文华; 宋金梅

    2004-01-01

    To study the dynamic changes of CT perfusion parameters during the first 12 h in the embolic cerebral ischemia models. Local cerebral ischemia model were established in 7 New Zealand white rabbits. All CT scans were performed with a GE Lightspeed 16 multislice CT. Following the baseline scan, further CT perfusion scans were performed at the same locations 20 min, 1-6 h and8, 10 and 12 h after the embolus delivery. Maps of all parameters were obtained by CT perfusion software at each time point. The brains, taken 12 h after the scan, were sliced corresponding to the positions of the CT slices and stained by 2,3,5-triphenyltetrazolium chloride (TTC). On the basis of the TTC results, the ischemicsides were divided into 3 regions: core, penumbra and the relatively normal region. The changes of all parameters were then divided into 3 stages. In the first two hours (the first stage), the CBV dropped more remarkably in the core than in the penumbra but rose slightly in the relatively normal region while the CBF decreased and MTT, TTP extended in all regions to varying degrees. In the 2nd-5th h (the second stage), all the parameters fluctuated slightly around a certain level. In the 5th-12th h (the third stage), the CBV and CBF dropped,and MTT and TTP were prolonged or shortened slightly in the core and penumbra though much notably in the former while the CBV, CBF roseand MTT, TTP were shortened remarkably in the relatively normal region. We experimentally demonstrated that the location and extent of cerebral ischemia could be accurately assessed by CT perfusion imaging. The pathophysiology of the ischemia could be reflected by the CT perfusion to varying degrees.

  4. Negative autoregulation by Fas stabilizes adult erythropoiesis and accelerates its stress response.

    Directory of Open Access Journals (Sweden)

    Miroslav Koulnis

    Full Text Available Erythropoiesis maintains a stable hematocrit and tissue oxygenation in the basal state, while mounting a stress response that accelerates red cell production in anemia, blood loss or high altitude. Thus, tissue hypoxia increases secretion of the hormone erythropoietin (Epo, stimulating an increase in erythroid progenitors and erythropoietic rate. Several cell divisions must elapse, however, before Epo-responsive progenitors mature into red cells. This inherent delay is expected to reduce the stability of erythropoiesis and to slow its response to stress. Here we identify a mechanism that helps to offset these effects. We recently showed that splenic early erythroblasts, 'EryA', negatively regulate their own survival by co-expressing the death receptor Fas, and its ligand, FasL. Here we studied mice mutant for either Fas or FasL, bred onto an immune-deficient background, in order to avoid an autoimmune syndrome associated with Fas deficiency. Mutant mice had a higher hematocrit, lower serum Epo, and an increased number of splenic erythroid progenitors, suggesting that Fas negatively regulates erythropoiesis at the level of the whole animal. In addition, Fas-mediated autoregulation stabilizes the size of the splenic early erythroblast pool, since mutant mice had a significantly more variable EryA pool than matched control mice. Unexpectedly, in spite of the loss of a negative regulator, the expansion of EryA and ProE progenitors in response to high Epo in vivo, as well as the increase in erythropoietic rate in mice injected with Epo or placed in a hypoxic environment, lagged significantly in the mutant mice. This suggests that Fas-mediated autoregulation accelerates the erythropoietic response to stress. Therefore, Fas-mediated negative autoregulation within splenic erythropoietic tissue optimizes key dynamic features in the operation of the erythropoietic network as a whole, helping to maintain erythroid homeostasis in the basal state, while

  5. Age-specific characteristics and coupling of cerebral arterial inflow and cerebrospinal fluid dynamics.

    Directory of Open Access Journals (Sweden)

    Marianne Schmid Daners

    Full Text Available The objective of this work is to quantify age-related differences in the characteristics and coupling of cerebral arterial inflow and cerebrospinal fluid (CSF dynamics. To this end, 3T phase-contrast magnetic resonance imaging blood and CSF flow data of eleven young (24 ± 3 years and eleven elderly subjects (70 ± 5 years with a comparable sex-ratio were acquired. Flow waveforms and their frequency composition, transfer functions from blood to CSF flows and cross-correlations were analyzed. The magnitudes of the frequency components of CSF flow in the aqueduct differ significantly between the two age groups, as do the frequency components of the cervical spinal CSF and the arterial flows. The males' aqueductal CSF stroke volumes and average flow rates are significantly higher than those of the females. Transfer functions and cross-correlations between arterial blood and CSF flow reveal significant age-dependence of phase-shift between these, as do the waveforms of arterial blood, as well as cervical-spinal and aqueductal CSF flows. These findings accentuate the need for age- and sex-matched control groups for the evaluation of cerebral pathologies such as hydrocephalus.

  6. Comprehensive validation of computational fluid dynamics simulationsof in-vivo blood flow in patient-specific cerebral aneurysms

    NARCIS (Netherlands)

    Sun, Q.; Groth, A.; Aach, T.

    2012-01-01

    Purpose: Recently, image-based computational fluid dynamic (CFD) simulations have been proposed to investigate the local hemodynamics inside human cerebral aneurysms. It is suggested that the knowledge ofthe computed three-dimensional flow fields can be used to assist clinical risk assessment and tr

  7. Stability depends on positive autoregulation in Boolean gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Ricardo Pinho

    2014-11-01

    Full Text Available Network motifs have been identified as building blocks of regulatory networks, including gene regulatory networks (GRNs. The most basic motif, autoregulation, has been associated with bistability (when positive and with homeostasis and robustness to noise (when negative, but its general importance in network behavior is poorly understood. Moreover, how specific autoregulatory motifs are selected during evolution and how this relates to robustness is largely unknown. Here, we used a class of GRN models, Boolean networks, to investigate the relationship between autoregulation and network stability and robustness under various conditions. We ran evolutionary simulation experiments for different models of selection, including mutation and recombination. Each generation simulated the development of a population of organisms modeled by GRNs. We found that stability and robustness positively correlate with autoregulation; in all investigated scenarios, stable networks had mostly positive autoregulation. Assuming biological networks correspond to stable networks, these results suggest that biological networks should often be dominated by positive autoregulatory loops. This seems to be the case for most studied eukaryotic transcription factor networks, including those in yeast, flies and mammals.

  8. Phantom-based experimental validation of computational fluid dynamics simulations on cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Sun Qi; Groth, Alexandra; Bertram, Matthias; Waechter, Irina; Bruijns, Tom; Hermans, Roel; Aach, Til [Philips Research Europe, Weisshausstrasse 2, 52066 Aachen (Germany) and Institute of Imaging and Computer Vision, RWTH Aachen University, Sommerfeldstrasse 24, 52074 Aachen (Germany); Philips Research Europe, Weisshausstrasse 2, 52066 Aachen (Germany); Philips Healthcare, X-Ray Pre-Development, Veenpluis 4-6, 5684PC Best (Netherlands); Institute of Imaging and Computer Vision, RWTH Aachen University, Sommerfeldstrasse 24, 52074 Aachen (Germany)

    2010-09-15

    Purpose: Recently, image-based computational fluid dynamics (CFD) simulation has been applied to investigate the hemodynamics inside human cerebral aneurysms. The knowledge of the computed three-dimensional flow fields is used for clinical risk assessment and treatment decision making. However, the reliability of the application specific CFD results has not been thoroughly validated yet. Methods: In this work, by exploiting a phantom aneurysm model, the authors therefore aim to prove the reliability of the CFD results obtained from simulations with sufficiently accurate input boundary conditions. To confirm the correlation between the CFD results and the reality, virtual angiograms are generated by the simulation pipeline and are quantitatively compared to the experimentally acquired angiograms. In addition, a parametric study has been carried out to systematically investigate the influence of the input parameters associated with the current measuring techniques on the flow patterns. Results: Qualitative and quantitative evaluations demonstrate good agreement between the simulated and the real flow dynamics. Discrepancies of less than 15% are found for the relative root mean square errors of time intensity curve comparisons from each selected characteristic position. The investigated input parameters show different influences on the simulation results, indicating the desired accuracy in the measurements. Conclusions: This study provides a comprehensive validation method of CFD simulation for reproducing the real flow field in the cerebral aneurysm phantom under well controlled conditions. The reliability of the CFD is well confirmed. Through the parametric study, it is possible to assess the degree of validity of the associated CFD model based on the parameter values and their estimated accuracy range.

  9. Deconvolution of dynamic dual photon microscopy images of cerebral microvasculature to assess the hemodynamic status of the brain

    Science.gov (United States)

    Mehrabian, Hatef; Lindvere, Liis; Stefanovic, Bojana; Martel, Anne L.

    2011-03-01

    Assessing the hemodynamic status of the brain and its variations in response to stimulations is required to understand the local cerebral circulatory mechanisms. Dynamic contrast enhanced imaging of cerebral microvasculature provides information that can be used in understanding physiology of cerebral diseases. Bolus tracking is used to extract characteristic parameters that quantify local cerebral blood flow. However, post-processing of the data is needed to segment the field of view (FOV) and to perform deconvolution to remove the effects of input bolus profile and the path it travels to reach the imaging window. Finding the arterial input function (AIF) and dealing with the ill-posedness of deconvolution system make this process are the main challenges. We propose using ICA to segment the FOV and to extract a local AIF as well as the venous output function that is required for deconvolution. This also helps to stabilize the system as ICA suppresses noise efficiently. Tikhoniv regularization (with L-curve analysis to find the best regularization parameter) is used to make the system stable. In-vivo dynamic 2PLSM images of a rat brain in two conditions (when the animal is at rest and when it is stimulated) are used in this study. The experimental along with the simulation studies provided promising results that demonstrate the feasibility and importance of performing deconvolution.

  10. Custom sizing of lower limb exoskeleton actuators using gait dynamic modelling of children with cerebral palsy.

    Science.gov (United States)

    Samadi, B; Achiche, S; Parent, A; Ballaz, L; Chouinard, U; Raison, M

    2016-11-01

    The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons should be designed to ease the movement of people with physical shortcoming, their design is generally based on data obtained from healthy adults, which leads to oversized components that are inadequate to the targeted users. Consequently, the objective of this study is to custom-size the lower limb exoskeleton actuators based on dynamic modeling of the human body for children with CP on the basis of hip, knee, and ankle joint kinematics and dynamics of human body during gait. For this purpose, a multibody modeling of the human body of 3 typically developed children (TD) and 3 children with CP is used. The results show significant differences in gait patterns especially in knee and ankle with respectively 0.39 and -0.33 (Nm/kg) maximum torque differences between TD children and children with CP. This study provides the recommendations to support the design of actuators to normalize the movement of children with CP.

  11. Custom sizing of lower limb exoskeleton actuators using gait dynamic modelling of children with cerebral palsy.

    Science.gov (United States)

    Samadi, B; Achiche, S; Parent, A; Ballaz, L; Chouinard, U; Raison, M

    2016-11-01

    The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons should be designed to ease the movement of people with physical shortcoming, their design is generally based on data obtained from healthy adults, which leads to oversized components that are inadequate to the targeted users. Consequently, the objective of this study is to custom-size the lower limb exoskeleton actuators based on dynamic modeling of the human body for children with CP on the basis of hip, knee, and ankle joint kinematics and dynamics of human body during gait. For this purpose, a multibody modeling of the human body of 3 typically developed children (TD) and 3 children with CP is used. The results show significant differences in gait patterns especially in knee and ankle with respectively 0.39 and -0.33 (Nm/kg) maximum torque differences between TD children and children with CP. This study provides the recommendations to support the design of actuators to normalize the movement of children with CP. PMID:26980164

  12. Multiple-input nonlinear modelling of cerebral haemodynamics using spontaneous arterial blood pressure, end-tidal CO2 and heart rate measurements.

    Science.gov (United States)

    Marmarelis, V Z; Mitsis, G D; Shin, D C; Zhang, R

    2016-05-13

    In order to examine the effect of changes in heart rate (HR) upon cerebral perfusion and autoregulation, we include the HR signal recorded from 18 control subjects as a third input in a two-input model of cerebral haemodynamics that has been used previously to quantify the dynamic effects of changes in arterial blood pressure and end-tidal CO2upon cerebral blood flow velocity (CBFV) measured at the middle cerebral arteries via transcranial Doppler ultrasound. It is shown that the inclusion of HR as a third input reduces the output prediction error in a statistically significant manner, which implies that there is a functional connection between HR changes and CBFV. The inclusion of nonlinearities in the model causes further statistically significant reduction of the output prediction error. To achieve this task, we employ the concept of principal dynamic modes (PDMs) that yields dynamic nonlinear models of multi-input systems using relatively short data records. The obtained PDMs suggest model-driven quantitative hypotheses for the role of sympathetic and parasympathetic activity (corresponding to distinct PDMs) in the underlying physiological mechanisms by virtue of their relative contributions to the model output. These relative PDM contributions are subject-specific and, therefore, may be used to assess personalized characteristics for diagnostic purposes. PMID:27044989

  13. Dynamic changes in fibrinogen levels of patients with acute cerebral infarction after taking defibrase

    Institute of Scientific and Technical Information of China (English)

    Yi Guo; Ling Wang; Bingshan Tang; Fangming Li; Qizhang Wang

    2008-01-01

    BACKGROUND: At present, as a therapeutic drug mainly for reducing fibrinogen (FIB) levels, the dynamic influence of defibrase on the FIB levels of patients with acute cerebral infarction has not been clearly ascertained.OBJECTIVE: To observe the dynamic changes in FIB levels of patients with acute cerebral infarction at different time points after taking defibrase.DESIGN, TIME AND SETTING: Randomized controlled clinical trial. The study was conducted in the Department of Neurology, the Second Affiliated Hospital of Jinan University, from June to November 2006.PARTICIPANTS: Sixty patients with acute cerebral infarction, who had been treated by the Neurological Department of the Second Affiliated Hospital of Jinan University from June to November 2006, were selected, including 37 males and 23 females, aged 35-75 years. All cases met the diagnostic criteria formulated by the Fourth National Cerebrovascular Disease Conference within 12 hours of onset. All the patients were confirmed with definite hemiparesis and cerebral infarction without coma, and were randomly divided into two groups: a treatment group (n=40) and a control group (n=20). Patients' families had the right to be informed and agree with the treatment, which had permission from the Hospital Ethics Committee.METHODS: Patients in the control group were given routine treatment with 30mL fleabane and 0.75g cytidine diphosphate added to 500mL saline solution once a day for 14 consecutive days. Patients in the treatment group were given routine treatment and Haiwang defibrase injection (purchased from Changchu Guoao Bio-Pharmaceutical Co. Ltd., Approval document number H10983237) within 12 hours of infarction. Defibrase doses of 15, 12.5 and 10U were given over 2 hours according to the patients' pre-treatment plasma FIB levels of ≥4.50g/L, 3.50-4.49g/L and 1.00-3.49g/L, respectively. Plasma FIB levels in the treatment group were measured before, and once every six hours for 48 hours after administration of

  14. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Di Rosa Giuseppe

    2011-05-01

    Full Text Available Abstract Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA, during which no force was applied, a force field adaptation phase (CF, and a wash-out phase (WO in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. Results During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Conclusions Spatial abnormalities in children affected

  15. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    Science.gov (United States)

    2011-01-01

    Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects) with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA), during which no force was applied, a force field adaptation phase (CF), and a wash-out phase (WO) in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. Results During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Conclusions Spatial abnormalities in children affected by cerebral palsy may be

  16. Cerebral hemodynamics in patients with obstructive sleep apnea syndrome monitored with near-infrared spectroscopy (NIRS) during positive airways pressure (CPAP) therapy: a pilot study

    Science.gov (United States)

    Zhang, Zhongxing; Schneider, Maja; Laures, Marco; Fritschi, Ursula; Lehner, Isabella; Qi, Ming; Khatami, Ramin

    2014-03-01

    In obstructive sleep apnea syndrome (OSA) the periodic reduction or cessation of breathing due to narrowing or occlusion of the upper airway during sleep leads to daytime symptoms and increased cardiovascular risk, including stroke. The higher risk of stroke is related to the impairment in cerebral vascular autoregulation. Continuous positive airways pressure (CPAP) therapy at night is the most effective treatment for OSA. However, there is no suitable bedside monitoring method evaluating the treatment efficacy of CPAP therapy, especially to monitor the recovery of cerebral hemodynamics. NIRS is ideally suited for non-invasive monitoring the cerebral hemodynamics during sleep. In this study, we will for first time assess dynamic changes of cerebral hemodynamics during nocturnal CPAP therapy in 3 patients with OSA using NIRS. We found periodic oscillations in HbO2, HHb, tissue oxygenation index (TOI) and blood volume associated with periodic apnea events without CPAP in all OSA patients. These oscillations were gradually attenuated and finally eliminated with the stepwise increments of CPAP pressures. The oscillations were totally eliminated in blood volume earlier than in other hemodynamic parameters. These results suggested that 1) the cerebral hemodynamic oscillations induced by OSA events can effectively be attenuated by CPAP therapy, and 2) blood flow and blood volume recovered first during CPAP therapy, followed by the recovery of oxygen consumption. Our study suggested that NIRS is a useful tool to evaluate the efficacy of CPAP therapy in patients with OSA bedside and in real time.

  17. Rhythmic components in renal autoregulation: Nonlinear modulation phenomena

    DEFF Research Database (Denmark)

    Pavlov, A. N.; Sosnovtseva, Olga; Pavlova, O. N.;

    2009-01-01

    Autoregulation of nephron blood flow involves two oscillatory processes: the tubular-flow sensitive tubuloglomerular feedback (TGF) mechanism and the blood-pressure sensitive myogenic mechanism. Both act to regulate the diameter of the afferent arteriole, which carries blood to the nephron. In th...... for normotensive rats, but irregular (or chaotic) for rats with hypertension. Modulation phenomena are clearly observed in both types of rats, but the effect is stronger in those with hypertension....

  18. Dose reduction in dynamic perfusion CT of the brain: effects of the scan frequency on measurements of cerebral blood flow, cerebral blood volume, and mean transit time

    Energy Technology Data Exchange (ETDEWEB)

    Wiesmann, Martin [University of Munich, Department of Neuroradiology, Muenchen (Germany); Klinikum der Universitaet Muenchen - Grosshadern, Abteilung fuer Neuroradiologie, Muenchen (Germany); Berg, Scott; Stoeckelhuber, B.M. [University of Luebeck, Department of Radiology, Luebeck (Germany); Bohner, G.; Klingebiel, R. [University Medicine Berlin, Department of Neuroradiology, Charite, Berlin (Germany); Schoepf, V.; Yousry, I.; Linn, J. [University of Munich, Department of Neuroradiology, Muenchen (Germany); Missler, U. [Evangelisches Krankenhaus Duisburg-Nord, Department of Neuroradiology, Duisburg (Germany)

    2008-12-15

    The influence of the frequency of computed tomography (CT) image acquistion on the diagnostic quality of dynamic perfusion CT (PCT) studies of the brain was investigated. Eight patients with clinically suspected acute ischemia of one hemisphere underwent PCT, performed on average 3.4 h after the onset of symptoms. Sixty consecutive images per slice were obtained with individual CT images obtained at a temporal resolution of two images per second. Eight additional data sets were reconstructed with temporal resolutions ranging from one image per second to one image per 5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) measurements were performed in identical regions of interest. Two neuroradiologists evaluated the PCT images visually to identify areas of abnormal perfusion. Perfusion images created up to a temporal resolution of one image per 3 s were rated to be diagnostically equal to the original data. Even at one image per 4 s, all areas of infarction were identified. Quantitative differences of CBF, CBV and MTT measurements were {<=}10% up to one image per 3 s. For PCT of the brain, temporal resolution can be reduced to one image per 3 s without significant compromise in image quality. This significantly reduces the radiation dose of the patient. (orig.)

  19. Contribution of hip joint proprioception to static and dynamic balance in cerebral palsy: a case control study

    OpenAIRE

    Damiano, Diane L.; Wingert, Jason R.; Stanley, Christopher J.; Curatalo, Lindsey

    2013-01-01

    Background Balance problems are common in cerebral palsy (CP) but etiology is often uncertain. The classic Romberg test compares ability to maintain standing with eyes open versus closed. Marked instability without vision is a positive test and generally indicates proprioceptive loss. From previous work showing diminished hip joint proprioception in CP, we hypothesized that static and dynamic balance without vision (positive Romberg) would be compromised in CP. Methods Force plate sway and ga...

  20. Spontaneous obliteration highlights the dynamic nature of cerebral arteriovenous malformations: A case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Su Lone Lim

    2016-01-01

    Conclusion: In our center′s 20-year experience of treatment of cerebral AVMs (approximately 600 cases, this is the only case that has been aborted due to spontaneous obliteration leading us to infer that the incidence of spontaneous AVM obliteration is <1%. Spontaneous obliteration of AVM is a rare but well-established phenomenon that bears testimony to the dynamics of this vascular disorder.

  1. Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: Rat cerebral glioma blood volume determination

    Science.gov (United States)

    Li, Xin; Rooney, William D.; Várallyay, Csanád G.; Gahramanov, Seymur; Muldoon, Leslie L.; Goodman, James A.; Tagge, Ian J.; Selzer, Audrey H.; Pike, Martin M.; Neuwelt, Edward A.; Springer, Charles S.

    2010-10-01

    The accurate mapping of the tumor blood volume (TBV) fraction ( vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume ( vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered.

  2. Effect of an acute increase in central blood volume on cerebral hemodynamics.

    Science.gov (United States)

    Ogoh, Shigehiko; Hirasawa, Ai; Raven, Peter B; Rebuffat, Thomas; Denise, Pierre; Lericollais, Romain; Sugawara, Jun; Normand, Hervé

    2015-10-15

    Systemic blood distribution is an important factor involved in regulating cerebral blood flow (CBF). However, the effect of an acute change in central blood volume (CBV) on CBF regulation remains unclear. To address our question, we sought to examine the CBF and systemic hemodynamic responses to microgravity during parabolic flight. Twelve healthy subjects were seated upright and exposed to microgravity during parabolic flight. During the brief periods of microgravity, mean arterial pressure was decreased (-26 ± 1%, P pulse pressure and estimated carotid sinus pressure increased rapidly. In addition, this increase in central arterial pulse pressure was associated with an arterial baroreflex-mediated decrease in heart rate (r = -0.888, P blood velocity (MCA Vmean) remained unchanged throughout parabolic flight (P = 0.30). During microgravity the contribution of cardiac output to MCA Vmean was gradually reduced (P < 0.05), and its contribution was negatively correlated with an increase in total vascular conductance (r = -0.683, P < 0.0001). These findings suggest that the acute loading of the arterial and cardiopulmonary baroreceptors by increases in CBV during microgravity results in acute and marked systemic vasodilation. Furthermore, we conclude that this marked systemic vasodilation decreases the contribution of cardiac output to CBF. These findings suggest that the arterial and cardiopulmonary baroreflex-mediated peripheral vasodilation along with dynamic cerebral autoregulation counteracts a cerebral overperfusion, which otherwise would occur during acute increases in CBV. PMID:26310936

  3. Arterial spin labelling MRI for assessment of cerebral perfusion in children with moyamoya disease: comparison with dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Goetti, Robert [University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); University Hospital Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); O' Gorman, Ruth [University Children' s Hospital Zurich, Center for MR Research, Zurich (Switzerland); Khan, Nadia [University Children' s Hospital Zurich, Moyamoya Center, Division of Neurosurgery, Department of Surgery, Zurich (Switzerland); Kellenberger, Christian J.; Scheer, Ianina [University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland)

    2013-05-15

    This study seeks to evaluate the diagnostic accuracy of cerebral perfusion imaging with arterial spin labelling (ASL) MR imaging in children with moyamoya disease compared to dynamic susceptibility contrast (DSC) imaging. Ten children (7 females; age, 9.2 {+-} 5.4 years) with moyamoya disease underwent cerebral perfusion imaging with ASL and DSC on a 3-T MRI scanner in the same session. Cerebral perfusion images were acquired with ASL (pulsed continuous 3D ASL sequence, 32 axial slices, TR = 5.5 s, TE = 25 ms, FOV = 24 cm, matrix = 128 x 128) and DSC (gradient echo EPI sequence, 35 volumes of 28 axial slices, TR = 2,000 ms, TE = 36 ms, FOV = 24 cm, matrix = 96 x 96, 0.2 ml/kg Gd-DOTA). Cerebral blood flow maps were generated. ASL and DSC images were qualitatively assessed regarding perfusion of left and right ACA, MCA, and PCA territories by two independent readers using a 3-point-Likert scale and quantitative relative cerebral blood flow (rCBF) was calculated. Correlation between ASL and DSC for qualitative and quantitative assessment and the accuracy of ASL for the detection of reduced perfusion per territory with DSC serving as the standard of reference were calculated. With a good interreader agreement ({kappa} = 0.62) qualitative perfusion assessment with ASL and DSC showed a strong and significant correlation ({rho} = 0.77; p < 0.001), as did quantitative rCBF (r = 0.79; p < 0.001). ASL showed a sensitivity, specificity and accuracy of 94 %, 93 %, and 93 % for the detection of reduced perfusion per territory. In children with moyamoya disease, unenhanced ASL enables the detection of reduced perfusion per vascular territory with a good accuracy compared to contrast-enhanced DSC. (orig.)

  4. Cerebral hemodynamics in normal-pressure hydrocephalus. Evaluation by 133Xe inhalation method and dynamic CT study

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, N.; Kusunoki, T.; Wakabayashi, T.; Matsumoto, S.

    1984-09-01

    Cerebral hemodynamics in 31 patients with suspected normal-pressure hydrocephalus were studied by means of the xenon-133 (133Xe) inhalation method and on dynamic computerized tomography (CT) scanning. Cerebral blood flow (CBF) is reduced in all patients with dementia. Hypoperfusion was noted in a frontal distribution in these patients compared with normal individuals. There was no difference in CBF patterns between patients with good and those with poor outcome. The CBF was increased following cerebrospinal fluid (CSF) shunting in patients who responded to that procedure: increase in flow correlated with clinical improvement, frontal and temporal lobe CBF was most markedly increased, and the CBF pattern became normal. In contrast, CBF was decreased after shunt placement in patients who were considered to have suffered from degenerative dementia, as evidenced by non-response to shunting. Dynamic computerized tomography studies demonstrated that patients with a good outcome showed a postoperative reduction in mean transit time of contrast material, most prominent in the frontal and temporal gray matter, and slight in the deep frontal structures, but not in the major cerebral vessels. Patients with poor outcome after shunting, however, had an increase in transit time in all regions. This corresponded well with the results as determined by the 133Xe inhalation method.

  5. Evolutionary tuning of protein expression levels of a positively autoregulated two-component system.

    Directory of Open Access Journals (Sweden)

    Rong Gao

    2013-10-01

    Full Text Available Cellular adaptation relies on the development of proper regulatory schemes for accurate control of gene expression levels in response to environmental cues. Over- or under-expression can lead to diminished cell fitness due to increased costs or insufficient benefits. Positive autoregulation is a common regulatory scheme that controls protein expression levels and gives rise to essential features in diverse signaling systems, yet its roles in cell fitness are less understood. It remains largely unknown how much protein expression is 'appropriate' for optimal cell fitness under specific extracellular conditions and how the dynamic environment shapes the regulatory scheme to reach appropriate expression levels. Here, we investigate the correlation of cell fitness and output response with protein expression levels of the E. coli PhoB/PhoR two-component system (TCS. In response to phosphate (Pi-depletion, the PhoB/PhoR system activates genes involved in phosphorus assimilation as well as genes encoding themselves, similarly to many other positively autoregulated TCSs. We developed a bacteria competition assay in continuous cultures and discovered that different Pi conditions have conflicting requirements of protein expression levels for optimal cell fitness. Pi-replete conditions favored cells with low levels of PhoB/PhoR while Pi-deplete conditions selected for cells with high levels of PhoB/PhoR. These two levels matched PhoB/PhoR concentrations achieved via positive autoregulation in wild-type cells under Pi-replete and -deplete conditions, respectively. The fitness optimum correlates with the wild-type expression level, above which the phosphorylation output saturates, thus further increase in expression presumably provides no additional benefits. Laboratory evolution experiments further indicate that cells with non-ideal protein levels can evolve toward the optimal levels with diverse mutational strategies. Our results suggest that the natural

  6. Role of the renin-angiotensin system in regulation and autoregulation of renal blood flow

    DEFF Research Database (Denmark)

    Sørensen, Charlotte Mehlin; Leyssac, Paul Peter; Skøtt, Ole;

    2000-01-01

    The role for ANG II in renal blood flow (RBF) autoregulation is unsettled. The present study was designed to test the effect of clamping plasma ANG II concentrations ([ANG II]) by simultaneous infusion of the angiotensin-converting enzyme inhibitor captopril and ANG II on RBF autoregulation in ha...

  7. Dynamics of activity free radical oxidation reactions in students with cerebral palsy results over the course of the educational process

    Directory of Open Access Journals (Sweden)

    Makarova E.V.

    2012-12-01

    Full Text Available The dynamics of changes activity of reactions is studied freely radical oxidize for students with the consequences of child's cerebral paralysis. 20 students took part in an experiment. Found that the course of study they have more active free radical oxidation reactions and decreases the activity of antiradical protection. Given the use of additional physical activity in aerobic training indicators intracellular antioxidant defense system increased, decreased content of reaction products of lipid peroxidation. However, increased rates of maximum oxygen consumption and increased tolerance of students with cerebral palsy to the consequences of physical activity. It is set that the pathological changes of metabolism for students ground the necessity of application of the differentiated physical loadings. The optimum forms of physical rehabilitation of the aerobic training is the dosed walking, medical swimming, dosed after distance, sometimes and by the corner of getting up pedestrian ascents. Loading is increased due to a volume, but not intensity of exercises.

  8. Dynamic temporal change of cerebral microbleeds: long-term follow-up MRI study.

    Directory of Open Access Journals (Sweden)

    Seung-Hoon Lee

    Full Text Available BACKGROUND: Cerebral microbleeds (MBs are understood as an important radiologic marker of intracerebral hemorrhage. We sought to investigate the temporal changes of MBs and clinical factors associated with the changes using long-term follow-up MRI. METHODS/PRINCIPAL FINDINGS: From October 2002 to July 2006, we prospectively enrolled patients with stroke or transient ischemic attack, and followed-up their brain MRIs with an interval >12 mo. We compared demographic factors, vascular risk factors, laboratory findings, and radiologic factors according to the presence or changes of MBs. A total of 224 patients successfully completed the follow-up examinations (mean, 27 months. Newly developed MBs were noted in 10 patients (6.8% among those without MBs at baseline (n = 148, and in those with MBs at baseline (n = 76, the MB count had decreased in 11 patients (14.5%, and increased in 41 patients (53.9%. The estimated annual rate of change of MB numbers was 0.80 lesions per year in all patients, a value which became greater in those patients who exhibited MBs at baseline (MBs≥5, 5.43 lesions per year. Strokes due to small vessel occlusion and intracerebral hemorrhage, as well as white matter lesions were independently associated with an increased MB count, whereas the highest quartile of low-density lipoprotein (LDL cholesterol was associated with a decreased MB count. CONCLUSION: During the follow-up period, most of MBs showed dynamic temporal change. Symptomatic or asymptomatic small vessel diseases appear to act as risk factors while in contrast, a high level of LDL cholesterol may act as a protective factor against MB increase.

  9. Attempts to Improve Absolute Quantification of Cerebral Blood Flow in Dynamic Susceptibility Contrast Magnetic Resonance Imaging: A Simplified T1-Weighted Steady-State Cerebral Blood Volume Approach

    Energy Technology Data Exchange (ETDEWEB)

    Wirestam, R.; Knutsson, L.; Risberg, J.; Boerjesson, S.; Larsson, E.M.; Gustafson, L.; Passant, U.; Staahlberg, F. [Depts. of Medical Radiation Physics, Diagnostic Radiology, Psychiatry, and Psychogeriatrics, Lund Univ, Lund (Sweden)

    2007-07-15

    Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations. Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate. Material and Methods: 17 volunteers were investigated by DSC-MRI and 133Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = KxCBF(DSC). Results: Average whole-brain SPECT CBF was 40.1{+-}6.9 ml/min 100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2{+-}13.8 ml/mi 100 g. After correction with the calibration factor, a CBF(ss) of 42.7{+-}14.0 ml/min 100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52). Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference 133Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.

  10. Analysis and dynamic 3D visualization of cerebral blood flow combining 3D and 4D MR image sequences

    Science.gov (United States)

    Forkert, Nils Daniel; Säring, Dennis; Fiehler, Jens; Illies, Till; Möller, Dietmar; Handels, Heinz

    2009-02-01

    In this paper we present a method for the dynamic visualization of cerebral blood flow. Spatio-temporal 4D magnetic resonance angiography (MRA) image datasets and 3D MRA datasets with high spatial resolution were acquired for the analysis of arteriovenous malformations (AVMs). One of the main tasks is the combination of the information of the 3D and 4D MRA image sequences. Initially, in the 3D MRA dataset the vessel system is segmented and a 3D surface model is generated. Then, temporal intensity curves are analyzed voxelwise in the 4D MRA image sequences. A curve fitting of the temporal intensity curves to a patient individual reference curve is used to extract the bolus arrival times in the 4D MRA sequences. After non-linear registration of both MRA datasets the extracted hemodynamic information is transferred to the surface model where the time points of inflow can be visualized color coded dynamically over time. The dynamic visualizations computed using the curve fitting method for the estimation of the bolus arrival times were rated superior compared to those computed using conventional approaches for bolus arrival time estimation. In summary the procedure suggested allows a dynamic visualization of the individual hemodynamic situation and better understanding during the visual evaluation of cerebral vascular diseases.

  11. The effect of negative autoregulation on eukaryotic gene expression

    Science.gov (United States)

    Nevozhay, Dmitry; Adams, Rhys; Murphy, Kevin; Josic, Kresimir; Balázsi, G. Ábor

    2009-03-01

    Negative autoregulation is a frequent motif in gene regulatory networks, which has been studied extensively in prokaryotes. Nevertheless, some effects of negative feedback on gene expression in eukaryotic transcriptional networks remain unknown. We studied how the strength of negative feedback regulation affects the characteristics of gene expression in yeast cells carrying synthetic transcriptional cascades. We observed a drastic reduction of gene expression noise and a change in the shape of the dose-response curve. We explained these experimentally observed effects by stochastic simulations and a simple set of algebraic equations.

  12. Multiresolution analysis of pathological changes in cerebral venous dynamics in newborn mice with intracranial hemorrhage: adrenorelated vasorelaxation

    International Nuclear Information System (INIS)

    Intracranial hemorrhage (ICH) is the major problem of modern neonatal intensive care. Abnormalities of cerebral venous blood flow (CVBF) can play a crucial role in the development of ICH in infants. The mechanisms underlying these pathological processes remain unclear; however it has been established that the activation of the adrenorelated vasorelaxation can be an important reason. Aiming to reach a better understanding of how the adrenodependent relaxation of cerebral veins contributes to the development of ICH in newborns, we study here the effects of pharmacological stimulation of adrenorelated dilation of the sagittal sinus by isoproterenol on the cerebral venous hemodynamics. Our study is performed in newborn mice at different stages of ICH using the laser speckle contrast imaging and wavelet analysis of the vascular dynamics of CVBF. We show that the dilation of the sagittal sinus with the decreased velocity of blood flow presides to the stress-induced ICH in newborn mice. These morphofunctional vascular changes are accompanied by an increased variance of the wavelet-coefficients in the areas of endothelial and non-endothelial (KATP-channels activity of vascular muscle) sympathetic components of the CVBF variability. Changes in the cerebral venous hemodynamics at the latent stage of ICH are associated with a high responsiveness of the sagittal sinus to isoproterenol quantifying by wavelet-coefficients related to a very slow region of the frequency domain. The obtained results certify that a high activation of the adrenergic-related vasodilatory responses to severe stress in newborn mice can be one of the important mechanisms underlying the development of ICH. Thus, the venous insufficiency with the decreased blood outflow from the brain associated with changes in the endothelial and the sympathetic components of CVBF-variability can be treated as prognostic criteria for the risk of ICH during the first days after birth. (paper)

  13. Neuropsychological Effects of Cerebral Amyloid Angiopathy.

    Science.gov (United States)

    Schrag, Matthew; Kirshner, Howard

    2016-08-01

    Cerebral amyloid angiopathy is a condition of the cerebral arterioles and to a lesser extent capillaries and veins, wherein beta-amyloid is deposited. In arterioles, this preferentially targets vascular smooth muscle cells and in the later stages undermines the stability of the vessel. This condition is frequently comorbid with Alzheimer's disease and its role in cognitive impairment and dementia is a topic of considerable recent research. This article reviews recent literature which confirms that CAA independently contributes to cognitive impairment by potentiating the neurodegeneration of Alzheimer's disease, by predisposing to microhemorrhagic and microischemic injury to the brain parenchyma, and by interfering with the autoregulation of CNS blood flow. In this review, we discuss the clinical presentation of cerebral amyloid angiopathy, with a focus on the neuropsychological manifestations of this vasculopathy. PMID:27357378

  14. Autoregulation of superficial nephron function in the alloperfused dog kidney.

    Science.gov (United States)

    Heller, J; Horácek, V

    1979-10-01

    Isolated dog kidneys were each pump-perfused by another dog during 4 experimental periods at perfusion pressures (PP) of 21, 17, 13, and 8 kPa, resp. (i.e. 160, 130, 94, and 60 mm Hg). At the 3 highest PP values, the total kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were perfectly autoregulated while at the lowest value both values were significantly lowered. No significant difference was observed between the single nephron GFR (SNGFR) of periods 1 and 2; in period 3 (PP = 13 kPa) a lower value was observed (P less than 0.05). Free flow pressure in proximal convolution (FFP), stop-flow pressure (SFP), and peritubular capillary pressure (PCP) were not different in period 2 than in period 1, but were significantly lower in period 3 (P = 0.02--0.05). Effective filtration pressure (EFP) was the highest in period 1, decreasing significantly with decreasing PP. Filtration pressure equilibrium was observed in period 4 at PP 8 kPa. Total blood flow resistance (RT) fell with decreasing PP, the drop being due to a steep decline in afferent resistance (RA). Efferent resistance (RE) increased as PP decreased. Ultrafiltration coefficient (Kf) rose with declining PP both within and outside the autoregulatory range. The results indicate that the lower limit of autoregulation is higher in superficial nephrons than in the whole kidney.

  15. Cerebral Blood Flow Dynamics and Head-of-Bed Changes in the Setting of Subarachnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    David K. Kung

    2013-01-01

    Full Text Available Head-of-bed (HOB elevation is usually restricted in patients with aneurysmal subarachnoid hemorrhage (SAH. The goal of this study is to correlate HOB changes ( and with cerebral blood flow using transcranial Doppler (TCD and thermal diffusion probe in SAH patients. Thirteen patients with SAH were prospectively enrolled in the study. Eight patients underwent placement of a thermal diffusion probe for regional CBF measurement. CBF values were measured with the patients in flat ( and upright sitting positions ( at days 3, 7, and 10. The average increase in blood flow velocity when changing HOB from to was 7.8% on day 3, 0.1% on day 7, and 13.1% on day 10. The middle cerebral artery had the least changes in velocity. The average regional CBF measurement was 22.7 ± 0.3 mL/100 g/min in the supine position and 23.6 ± 9.1 mg/100 g/min in the sitting position. The changes were not statistically significant. None of the patients developed clinical cerebral vasospasm. Changing HOB position in the setting of SAH did not significantly affect cerebral or regional blood flow. These data suggest that early mobilization should be considered given the detrimental effects of prolonged bed rest.

  16. The Dynamic cerebral autoregulatory adaptive response to noradrenaline is attenuated during systemic inflammation in humans

    DEFF Research Database (Denmark)

    Berg, Ronan M. G.; Plovsing, Ronni R.; Bailey, Damian M.;

    2015-01-01

    and repeated after a 4-h intravenous LPS infusion. The assessments of dCA were based on transfer function analysis of spontaneous oscillations between MAP and middle cerebral artery blood flow velocity measured by transcranial Doppler ultrasound in the low frequency range (0.07-0.20 Hz). Prior to LPS...

  17. Regional cerebral blood flow by radioxenon-113 inhalation and dynamic emission tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Paulson, O B

    1981-01-01

    at a concentration of 10 mCi/l for 1 min. The algorithm used to calculate rCBF is described, and clinical results in particular in stroke cases are presented. The rapidly rotating tomograph is better suited for the study of focal cerebral ischemia than the conventional stationary detectors because superposition...

  18. Dominant negative autoregulation limits steady-state repression levels in gene networks.

    Science.gov (United States)

    Semsey, Szabolcs; Krishna, Sandeep; Erdossy, János; Horváth, Péter; Orosz, László; Sneppen, Kim; Adhya, Sankar

    2009-07-01

    Many transcription factors repress transcription of their own genes. Negative autoregulation has been shown to reduce cell-cell variation in regulatory protein levels and speed up the response time in gene networks. In this work we examined transcription regulation of the galS gene and the function of its product, the GalS protein. We observed a unique operator preference of the GalS protein characterized by dominant negative autoregulation. We show that this pattern of regulation limits the repression level of the target genes in steady states. We suggest that transcription factors with dominant negative autoregulation are designed for regulating gene expression during environmental transitions. PMID:19429616

  19. Double-wavelet approach to study frequency and amplitude modulation in renal autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A N; Mosekilde, E;

    2004-01-01

    Biological time series often display complex oscillations with several interacting rhythmic components. Renal autoregulation, for instance, involves at least two separate mechanisms both of which can produce oscillatory variations in the pressures and flows of the individual nephrons. Using double...

  20. Double-wavelet approach to study frequency and amplitude modulation in renal autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik;

    2004-01-01

    Biological time series often display complex oscillations with several interacting rhythmic components. Renal autoregulation, for instance, involves at least two separate mechanisms both of which can produce oscillatory variations in the pressures and flows of the individual nephrons. Using doubl...

  1. No apparent role for T-type Ca²⁺ channels in renal autoregulation.

    Science.gov (United States)

    Frandsen, Rasmus Hassing; Salomonsson, Max; Hansen, Pernille B L; Jensen, Lars J; Braunstein, Thomas Hartig; Holstein-Rathlou, Niels-Henrik; Sorensen, Charlotte Mehlin

    2016-04-01

    Renal autoregulation protects glomerular capillaries against increases in renal perfusion pressure (RPP). In the mesentery, both L- and T-type calcium channels are involved in autoregulation. L-type calcium channels participate in renal autoregulation, but the role of T-type channels is not fully elucidated due to lack of selective pharmacological inhibitors. The role of T- and L-type calcium channels in the response to acute increases in RPP in T-type channel knockout mice (CaV3.1) and normo- and hypertensive rats was examined. Changes in afferent arteriolar diameter in the kidneys from wild-type and CaV3.1 knockout mice were assessed. Autoregulation of renal blood flow was examined during acute increases in RPP in normo- and hypertensive rats under pharmacological blockade of T- and L-type calcium channels using mibefradil (0.1 μM) and nifedipine (1 μM). In contrast to the results from previous pharmacological studies, genetic deletion of T-type channels CaV3.1 did not affect renal autoregulation. Pharmacological blockade of T-type channels using concentrations of mibefradil which specifically blocks T-type channels also had no effect in wild-type or knockout mice. Blockade of L-type channels significantly attenuated renal autoregulation in both strains. These findings are supported by in vivo studies where blockade of T-type channels had no effect on changes in the renal vascular resistance after acute increases in RPP in normo- and hypertensive rats. These findings show that genetic deletion of T-type channels CaV3.1 or treatment with low concentrations of mibefradil does not affect renal autoregulation. Thus, T-type calcium channels are not involved in renal autoregulation in response to acute increases in RPP.

  2. Malignant cerebral swelling following cranioplasty.

    Science.gov (United States)

    Honeybul, S; Damodaran, O; Lind, C R P; Lee, G

    2016-07-01

    Over the past few years there have been a number of case reports and small cohort studies that have described so called "malignant" cerebral swelling following an uneventful cranioplasty procedure. The pathophysiology remains to be established however it has been suggested that it may be related to a combination of failure of autoregulation and the use of closed vacuum suction drainage. The current study presents three further patients who had had a decompressive hemicraniectomy for ischaemic stroke. If decompressive craniectomy is utilised in the management of neurological emergencies, close attention and wider reporting of this type of complication is required not only to focus attention on possible management strategies, but also to determine which patients are at most risk of this devastating complication. PMID:27189792

  3. The effect of training in an interactive dynamic stander on ankle dorsiflexion and gross motor function in children with cerebral palsy

    DEFF Research Database (Denmark)

    Curtis, Derek John; Bencke, Jesper; Mygind, Bente

    2014-01-01

    OBJECTIVE: To study the effect of active stretching of ankle plantarflexors using an interactive dynamic stander in children with cerebral palsy (CP). METHODS: Six children in Gross Motor Function Classification System classes I-III, aged 4-10 years, trained intensive active dorsiflexion in an in...

  4. Spontaneous low-frequency oscillations in cerebral vessels

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Hansson, Andreas; Phillip, Dorte;

    2010-01-01

    The etiology behind and physiological significance of spontaneous oscillations in the low-frequency spectrum in both systemic and cerebral vessels remain unknown. Experimental studies have proposed that spontaneous oscillations in cerebral blood flow reflect impaired cerebral autoregulation (CA......). Analysis of CA by measurement of spontaneous oscillations in the low-frequency spectrum in cerebral vessels might be a useful tool for assessing risk and investigating different treatment strategies in carotid artery disease (CAD) and stroke. We reviewed studies exploring spontaneous oscillations...... in the low-frequency spectrum in patients with CAD and ischemic stroke, conditions known to involve impaired CA. Several studies have reported changes in oscillations after CAD and stroke after surgery and over time compared with healthy controls. Phase shift in the frequency domain and correlation...

  5. Developmental dynamics of radial vulnerability in the cerebral compartments in preterm infants and neonates

    Directory of Open Access Journals (Sweden)

    Ivica eKostović

    2014-07-01

    Full Text Available The developmental vulnerability of different classes of axonal pathways in preterm white matter is not known. We propose that laminar compartments of the developing cerebral wall serve as spatial framework for axonal growth and evaluate potential of anatomical landmarks for understanding reorganization of the cerebral wall after perinatal lesions. The 3T MRI (in vivo and histological analysis were performed in a series of cases ranging from 22 PCW to 3 years. For the follow-up scans, three groups of children (control, normotypic and preterms with lesions were examined at the term equivalent age and after the first year of life. MRI and histological abnormalities were analyzed in the following compartments: (a periventricular, with periventricular fibre system; (b intermediate, with periventricular crossroads, sagittal strata and centrum semiovale; (c superficial, composed of gyral white matter, subplate and cortical plate. Vulnerability of thalamo-cortical pathways within the crossroads and sagittal strata seems to be characteristic for early preterms, while vulnerability of long association pathways in the centrum semiovale seems to be predominant feature of late preterms. The structural indicator of the lesion of the long association pathways is the loss of delineation between centrum semiovale and subplate remnant, which is possible substrate of the diffuse periventricular leukomalacia. The enhanced difference in MR signal intensity of centrum semiovale and subplate remnant, observed in damaged children after first year, we interpret as structural plasticity of intact short cortico-cortical fibres, which grow postnatally through U-zones and enter the cortex through the subplate remnant. Our findings indicate that radial distribution of MRI signal abnormalities in the cerebral compartments may be related to lesion of different classes of axonal pathways and have prognostic value for predicting the likely outcome of prenatal and perinatal

  6. Developmental dynamics of radial vulnerability in the cerebral compartments in preterm infants and neonates.

    Science.gov (United States)

    Kostović, Ivica; Kostović-Srzentić, Mirna; Benjak, Vesna; Jovanov-Milošević, Nataša; Radoš, Milan

    2014-01-01

    The developmental vulnerability of different classes of axonal pathways in preterm white matter is not known. We propose that laminar compartments of the developing cerebral wall serve as spatial framework for axonal growth and evaluate potential of anatomical landmarks for understanding reorganization of the cerebral wall after perinatal lesions. The 3-T MRI (in vivo) and histological analysis were performed in a series of cases ranging from 22 postconceptional weeks to 3 years. For the follow-up scans, three groups of children (control, normotypic, and preterms with lesions) were examined at the term equivalent age and after the first year of life. MRI and histological abnormalities were analyzed in the following compartments: (a) periventricular, with periventricular fiber system; (b) intermediate, with periventricular crossroads, sagittal strata, and centrum semiovale; (c) superficial, composed of gyral white matter, subplate, and cortical plate. Vulnerability of thalamocortical pathways within the crossroads and sagittal strata seems to be characteristic for early preterms, while vulnerability of long association pathways in the centrum semiovale seems to be predominant feature of late preterms. The structural indicator of the lesion of the long association pathways is the loss of delineation between centrum semiovale and subplate remnant, which is possible substrate of the diffuse periventricular leukomalacia. The enhanced difference in MR signal intensity of centrum semiovale and subplate remnant, observed in damaged children after first year, we interpret as structural plasticity of intact short cortico-cortical fibers, which grow postnatally through U-zones and enter the cortex through the subplate remnant. Our findings indicate that radial distribution of MRI signal abnormalities in the cerebral compartments may be related to lesion of different classes of axonal pathways and have prognostic value for predicting the likely outcome of prenatal and

  7. Cerebral Hypoxia

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Cerebral Hypoxia Information Page Synonym(s): Hypoxia, Anoxia Table of Contents ( ... Trials Organizations Publicaciones en Español What is Cerebral Hypoxia? Cerebral hypoxia refers to a condition in which ...

  8. Quantitative comparison of hemodynamics in simulated and 3D angiography models of cerebral aneurysms by use of computational fluid dynamics.

    Science.gov (United States)

    Saho, Tatsunori; Onishi, Hideo

    2015-07-01

    In this study, we evaluated hemodynamics using simulated models and determined how cerebral aneurysms develop in simulated and patient-specific models based on medical images. Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM software. Flow velocity, stream line, and wall shear stress (WSS) were evaluated in a simulated model aneurysm with known geometry and in a three-dimensional angiographic model. The ratio of WSS at the aneurysm compared with that at the basilar artery was 1:10 in simulated model aneurysms with a diameter of 10 mm and 1:18 in the angiographic model, indicating similar tendencies. Vortex flow occurred in both model aneurysms, and the WSS decreased in larger model aneurysms. The angiographic model provided accurate CFD information, and the tendencies of simulated and angiographic models were similar. These findings indicate that hemodynamic effects are involved in the development of aneurysms. PMID:25911446

  9. Noninvasive xenon-133 measurements of cerebral blood flow using stationary detectors compared with dynamic emission tomography

    DEFF Research Database (Denmark)

    Schroeder, T; Vorstrup, S; Lassen, N A;

    1986-01-01

    Repeated bedside measurements of CBF have been made possible by the recent development of a mobile unit with 10 stationary detectors using the intravenous xenon-133 method. To evaluate this technique, comparative CBF studies at rest and following the application of a cerebral vasodilatory stimulus...... (acetazolamide, 1 g i.v.) were performed with the mobile equipment and with xenon-133 single-photon emission inhalation tomography in patients with cerebrovascular disease. The CBF level and the flow response to acetazolamide as determined with the two methods were well correlated, although at low flow levels...... the stationary detectors yielded somewhat lower CBF values than did emission tomography. Considering the side-to-side asymmetry, an excellent correlation was obtained. Using the initial slope index, the stationary detectors revealed quantitatively 83% of the interhemispheric asymmetry and 63% of the asymmetry...

  10. Clinical Neuroimaging of cerebral ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawara, Jyoji [Nakamura Memorial Hospital, Sapporo (Japan)

    1999-06-01

    Notice points in clinical imaging of cerebral ischemia are reviewed. When cerebral blood flow is determined in acute stage of cerebral embolism (cerebral blood flow SPECT), it is important to find area of ischemic core and ischemic penumbra. When large cortex area is assigned to ischemic penumbra, thrombolytic therapy is positively adapted, but cautious correspondence is necessary when ischemic core is recognized. DWI is superior in the detection of area equivalent to ischemic core of early stage, but, in imaging of area equivalent to ischemic penumbra, perfusion image or distribution image of cerebral blood volume (CBV) by MRI need to be combined. Luxury perfusion detected by cerebral blood flow SPECT in the cases of acute cerebral embolism suggests vascular recanalization, but a comparison with CT/MRI and continuous assessment of cerebral circulation dynamics were necessary in order to predict brain tissue disease (metabolic abnormality). In hemodynamic cerebral ischemia, it is important to find stage 2 equivalent to misery perfusion by quantification of cerebral blood flow SPECT. Degree of diaschisis can indicate seriousness of brain dysfunction for lacuna infarct. Because cerebral circulation reserve ability (perfusion pressure) is normal in all areas of the low cerebral blood flow by diaschisis mechanism, their areas are easily distinguished from those of hemodynamic cerebral ischemia. (K.H.)

  11. Cooperativity of Negative Autoregulation Confers Increased Mutational Robustness

    Science.gov (United States)

    Marciano, David C.; Lua, Rhonald C.; Herman, Christophe; Lichtarge, Olivier

    2016-06-01

    Negative autoregulation is universally found across organisms. In the bacterium Escherichia coli, transcription factors often repress their own expression to form a negative feedback network motif that enables robustness to changes in biochemical parameters. Here we present a simple phenomenological model of a negative feedback transcription factor repressing both itself and another target gene. The strength of the negative feedback is characterized by three parameters: the cooperativity in self-repression, the maximal expression rate of the transcription factor, and the apparent dissociation constant of the transcription factor binding to its own promoter. Analysis of the model shows that the target gene levels are robust to mutations in the transcription factor, and that the robustness improves as the degree of cooperativity in self-repression increases. The prediction is tested in the LexA transcriptional network of E. coli by altering cooperativity in self-repression and promoter strength. Indeed, we find robustness is correlated with the former. Considering the proposed importance of gene regulation in speciation, parameters governing a transcription factor's robustness to mutation may have significant influence on a cell or organism's capacity to evolve.

  12. Basal forebrain thermoregulatory mechanism modulates auto-regulated sleep

    Directory of Open Access Journals (Sweden)

    Hruda N Mallick

    2012-06-01

    Full Text Available Regulation of body temperature and sleep are two physiological mechanisms that are vital for our survival. Interestingly neural structures implicated in both these functions are common. These areas include the medial preoptic area, the lateral preoptic area, the ventrolateral preoptic area, the median preoptic nucleus and the medial septum, which form part of the basal forebrain.When given a choice, rats prefer to stay at an ambient temperature of 270C, though the maximum sleep was observed when they were placed at 300C. Ambient temperature around 270C should be considered as the thermoneutral temperature for rats in all sleep studies. At this temperature the diurnal oscillations of sleep and body temperature are properly expressed. The warm sensitive neurons of the preoptic area mediate the increase in sleep at 300C. Promotion of sleep during the rise in ambient temperature from 270C to 300C, serve a thermoregulatory function. Autonomous thermoregulatory changes in core body temperature and skin temperature could act as an input signal to modulate neuronal activity in sleep-promoting brain areas. The studies presented here show that the neurons of the basal forebrain play a key role in regulating sleep. Basal forebrain thermoregulatory system is a part of the global homeostatic sleep regulatory mechanism, which is auto-regulated.

  13. Influence of centrally administered α- and γ2-melanocyte-stimulating hormone on hypothalamic blood flow autoregulation in the rat

    NARCIS (Netherlands)

    Sandor, P.; Jong, Wybren de; Cox-van Put, J.; Wied, D. de

    1987-01-01

    The effect of intracerebroventricularly (i.c.v.) administered α-melanocyte-stimulating hormone (MSH) and γ2-MSH on hypothalamic blood flow autoregulation was studied in anesthetized rats at different levels of standardized arterial hypotension. Autoregulation was impaired upon i.c.v. administration

  14. Tuberculoma cerebral Cerebral tuberculoma

    OpenAIRE

    ELIZABETH CLARA BARROSO; TÂNIA REGINA BRÍGIDO DE OLIVEIRA; ANA MARIA DANTAS DO AMARAL; VALÉRIA GÓES FERREIRA PINHEIRO; ANA LÚCIA DE OLIVEIRA SOUSA

    2002-01-01

    Relata-se o caso de paciente com crises convulsivas de início recente. A tomografia computadorizada cerebral evidenciou imagem sugestiva de lesão expansiva metastática frontoparietal direita. A investigação de tumor primário ou outra doença foi negativa e o exame histopatológico do tecido cerebral diagnosticou tuberculoma. As convulsões foram controladas com a associação de hidantoína 300mg/dia ao esquema específico, utilizado por 18 meses. A tuberculose do sistema nervoso central representa ...

  15. Real-time imaging reveals the dynamics of leukocyte behaviour during experimental cerebral malaria pathogenesis.

    Directory of Open Access Journals (Sweden)

    Saparna Pai

    2014-07-01

    Full Text Available During experimental cerebral malaria (ECM mice develop a lethal neuropathological syndrome associated with microcirculatory dysfunction and intravascular leukocyte sequestration. The precise spatio-temporal context in which the intravascular immune response unfolds is incompletely understood. We developed a 2-photon intravital microscopy (2P-IVM-based brain-imaging model to monitor the real-time behaviour of leukocytes directly within the brain vasculature during ECM. Ly6C(hi monocytes, but not neutrophils, started to accumulate in the blood vessels of Plasmodium berghei ANKA (PbA-infected MacGreen mice, in which myeloid cells express GFP, one to two days prior to the onset of the neurological signs (NS. A decrease in the rolling speed of monocytes, a measure of endothelial cell activation, was associated with progressive worsening of clinical symptoms. Adoptive transfer experiments with defined immune cell subsets in recombinase activating gene (RAG-1-deficient mice showed that these changes were mediated by Plasmodium-specific CD8(+ T lymphocytes. A critical number of CD8(+ T effectors was required to induce disease and monocyte adherence to the vasculature. Depletion of monocytes at the onset of disease symptoms resulted in decreased lymphocyte accumulation, suggesting reciprocal effects of monocytes and T cells on their recruitment within the brain. Together, our studies define the real-time kinetics of leukocyte behaviour in the central nervous system during ECM, and reveal a significant role for Plasmodium-specific CD8(+ T lymphocytes in regulating vascular pathology in this disease.

  16. Laser speckle contrast reveals cerebral blood flow dynamics evoked by optogenetically controlled neuronal activity

    Science.gov (United States)

    Li, Nan; Thakor, Nitish V.; Pelled, Galit

    2013-03-01

    As a critical basis of functional brain imaging, neurovascular coupling describes the link between neuronal and hemodynamic changes. The majority of in vivo neurovascular coupling studies was performed by inducing sensory stimulation via afferent inputs. Unfortunately such an approach results in recruiting of multiple types of cells, which confounds the explanation of neuronal roles in stimulus evoked hemodynamic changes. Recently optogenetics has emerged to provide immediate control of neurons by exciting or inhibiting genetically engineered neurons expressing light sensitive proteins. However, there is a need for optical methods capable of imaging the concurrent hemodynamic changes. We utilize laser speckle contrast imaging (LSCI) to obtain high resolution display of cerebral blood flow (CBF) in the vicinity of the targeted neural population. LSCI is a minimally invasive method for imaging CBF in microvessels through thinned skull, and produces images with high spatiotemporal resolution, wide field of view. In the integrated system light sources with different wavelengths and band-passing/blocking filters were used to allow simultaneous optical manipulation of neuronal activities and optical imaging of corresponding CBF. Experimental studies were carried out in a rodent model expressing channalrhodopsin (ChR2) in excitatory neurons in the somatosensory cortex (S1). The results demonstrated significant increases of CBF in response to ChR2 stimulation (exciting neuronal firing) comparable to the CBF response to contralateral forepaw stimulation. The approach promises to be an exciting minimally invasive method to study neurovascular coupling. The complete system provides a novel approach for broad neuroscience applications.

  17. Autoregulation of glomerular filtration rate during spironolactone treatment in hypertensive patients with type 1 diabetes: a randomized crossover trial

    DEFF Research Database (Denmark)

    Schjoedt, K.J.; Christensen, P.K.; Jorsal, A.;

    2009-01-01

    BACKGROUND: Autoregulation of GFR, i.e. maintenance of relative constancy of GFR despite variations in mean arterial pressure (MAP) >80 mmHg, is impaired in diabetic kidney disease; furthermore, some antihypertensive drugs may jeopardize autoregulation. The aim of our study was to establish...... if spironolactone affects the ability to autoregulate GFR. METHODS: Sixteen hypertensive type 1 diabetic patients with persistent normoalbuminuria (presumed normal autoregulation) completed this randomized, double-masked, crossover trial. After a 4-week wash-out period, patients received spironolactone 25 mg o.......d. and matched placebo for 4 weeks in random order. After each treatment period, the ability to autoregulate GFR was determined by measuring GFR ((51)Cr-EDTA clearance) before (basal) and after acute blood pressure reduction by intravenous injection of clonidine. RESULTS: During placebo, the mean (SE) basal GFR...

  18. Loss of autoregulation of blood flow in subcutaneous tissue in juvenile diabetes

    DEFF Research Database (Denmark)

    Henriksen, O; Kastrup, J; Parving, H H;

    1984-01-01

    and retinopathy. The blood flow remained constant in all normal subjects, when the arterial perfusion pressure was varied between 70 and 150 mm Hg. All diabetics had impaired or reduced autoregulation of the subcutaneous blood flow. The blood flow increased and decreased almost linearly with the changes...... in arterial perfusion pressure. The mechanism underlying the defect autoregulation of blood flow in diabetics is uncertain; possibilities include structural changes of the arterioles and/or alterations of local metabolic factors.......The autoregulation of blood flow in subcutaneous tissue was investigated at the level of the lateral malleolus by the local 133Xenon washout technique. We have investigated eight long-term insulin-dependent diabetics and seven healthy controls. All diabetics had moderate diabetic nephropathy...

  19. Mathematical model for blood flow autoregulation by endothelium-derived relaxing factor

    CERN Document Server

    Chernyavsky, I L; Chernyavsky, Igor L.; Kudryashov, Nikolai A.

    2006-01-01

    The fluid shear stress is an important regulator of the cardiovascular system via the endothelium-derived relaxing factor (EDRF) that is Nitric Oxide. This mechanism involves biochemical reactions in an arterial wall. The autoregulation process is managed by the vascular tonus and gives the negative feedback for the shear stress changing. A new mathematical model for the autoregulation of a blood flow through arteria under the constant transmural pressure is presented. Endothelium-derived relaxing factor Nitric Oxide, the multi-layer structure of an arterial wall, and kinetic-diffusion processes are taken into consideration. The limit case of the thin-wall artery is analytically studied. The stability condition for a stationary point of the linearized system is given. The exact stationary solutions of the origin system are found. The numerical simulation for the autoregulation system is presented. It is shown the arteria adaptation to an initial radial perturbation and the transition of the system to new equi...

  20. Clinical and neuroradiological studies of eclampsia. Cerebral vasospasm and relation to the brain edema

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yasuhiro; Niwa, Hisayoshi; Ando, Tetsuo; Yasuda, Takeshi; Yanagi, Tsutomu [Nagoya Daini Red Cross Hospital, Aichi (Japan)

    1995-04-01

    Clinical and neuroradiological studies involving cerebral angiography were conducted in four patients with eclampsia. In three cases (case 1, 2 and 4), neurological focal signs, abnormal low density areas on cranial CT and T{sub 2} high intensity areas on cranial MRI disappeared within a month. But in one case (case 3), cerebral infarction occurred and right hemiparesis and aphasia persisted. Cerebral angiography in the acute phase demonstrated vasospasm in all cases and arterial occlusion in the middle cerebral artery due to vasospasm in case 3. Angiography demonstrated several types of spasms, including diffuse, peripheral and multi local. Furthermore, in some cases, diffuse vasospasms were recognized at the siphon and extracranial portions of the internal carotid artery. In one case (Case 4), segmental vasospasms were detected in the bilateral vertebral arteries. Three to four weeks later, follow-up cerebral angiography was performed in three cases. Cerebral vasospasms had partially or completely recovered. Subarachnoid hemorrhage (SAH) was excluded by lumbar puncture and neuroradiological findings in all cases. We concluded that eclampsia itself causes cerebral vasospasm and that the mechanism of vasospasm is different from that of SAH, since cerebral vasospasm occurred in the extracranial cerebral arteries. We suspected that cerebral vasospasm in eclampsia causes cerebral ischemia, which leads to cytotoxic edema and dysfunction of the blood-brain barrier (BBB) and cerebral autoregulation. With this background, brain edema, especially vasogenic edema, may easily occur and clinical symptoms of eclampsia may appear when the blood pressure rapidly increases. (author).

  1. Bidirectional Contrast agent leakage correction of dynamic susceptibility contrast (DSC)-MRI improves cerebral blood volume estimation and survival prediction in recurrent glioblastoma treated with bevacizumab.

    OpenAIRE

    Ab, KL; Boxerman, JL; Lai, A.; Nghiemphu, PL; Pope, WB; Cloughesy, TF; Ellingson, BM

    2016-01-01

    To evaluate a leakage correction algorithm for T1 and T2* artifacts arising from contrast agent extravasation in dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) that accounts for bidirectional contrast agent flux and compare relative cerebral blood volume (CBV) estimates and overall survival (OS) stratification from this model to those made with the unidirectional and uncorrected models in patients with recurrent glioblastoma (GBM).We determined median rCBV within contras...

  2. Application of Gaussian moment method to a gene autoregulation model of rational vector field

    Science.gov (United States)

    Kang, Yan-Mei; Chen, Xi

    2016-07-01

    We take a lambda expression autoregulation model driven by multiplicative and additive noises as example to extend the Gaussian moment method from nonlinear stochastic systems of polynomial vector field to noisy biochemical systems of rational polynomial vector field. As a direct application of the extended method, we also disclose the phenomenon of stochastic resonance. It is found that the transcription rate can inhibit the stochastic resonant effect, but the degradation rate may enhance the phenomenon. These observations should be helpful in understanding the functional role of noise in gene autoregulation.

  3. Sympathetic influence on cerebral blood flow and metabolism during exercise in humans

    DEFF Research Database (Denmark)

    Seifert, Thomas; Secher, Niels H

    2011-01-01

    This review focuses on the possibility that autonomic activity influences cerebral blood flow (CBF) and metabolism during exercise in humans. Apart from cerebral autoregulation, the arterial carbon dioxide tension, and neuronal activation, it may be that the autonomic nervous system influences CBF...... as evidenced by pharmacological manipulation of adrenergic and cholinergic receptors. Cholinergic blockade by glycopyrrolate blocks the exercise-induced increase in the transcranial Doppler determined mean flow velocity (MCA Vmean). Conversely, alpha-adrenergic activation increases that expression of cerebral...... perfusion and reduces the near-infrared determined cerebral oxygenation at rest, but not during exercise associated with an increased cerebral metabolic rate for oxygen (CMRO(2)), suggesting competition between CMRO(2) and sympathetic control of CBF. CMRO(2) does not change during even intense handgrip...

  4. Is correction necessary when clinically determining quantitative cerebral perfusion parameters from multi-slice dynamic susceptibility contrast MR studies?

    Science.gov (United States)

    Salluzzi, M.; Frayne, R.; Smith, M. R.

    2006-01-01

    Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies. Preliminary results associated with this paper were presented at ISMRM 12th Scientific Meeting and Exhibition, Kyoto, Japan, 2004.

  5. Cerebral Palsy

    Science.gov (United States)

    Cerebral palsy is a group of disorders that affect a person's ability to move and to maintain balance ... do not get worse over time. People with cerebral palsy may have difficulty walking. They may also have ...

  6. Dynamic susceptibility contrast-enhanced MRI evaluation of cerebral intraventricular tumors: preliminary results.

    OpenAIRE

    Holveck, A.; Grand, Sylvie; Boini, Stéphane; Kirchin, Miles; Le Bas, Jean-François; Dietemann, Jean-Louis; Bracard, Serge; Kremer, Stéphane

    2010-01-01

    International audience INTRODUCTION: The aims of the present study were to determine the perfusion characteristics of several types of intraventricular tumors and to evaluate the usefulness of dynamic contrast-enhanced MRI in making the differential diagnosis. METHODS: A total of 28 patients with intraventricular tumors (five meningiomas, five papillomas, three ependymomas, four subependymomas, seven central neurocytomas, two subependymal giant cell astrocytomas and two metastases) underwe...

  7. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    OpenAIRE

    Di Rosa Giuseppe; Morasso Pietro; Frascarelli Flaminia; Masia Lorenzo; Petrarca Maurizio; Castelli Enrico; Cappa Paolo

    2011-01-01

    Abstract Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of sub...

  8. Human cerebral circulation. Positron emission tomography studies

    International Nuclear Information System (INIS)

    We reviewed the literature on human cerebral circulation and oxygen metabolism, as measured by positron emission tomography (PET), with respect to normal values and of regulation of cerebral circulation. A multicenter study in Japan showed that between-center variations in cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) values were not considerably larger than the corresponding within-center variations. Overall mean±SD values in cerebral cortical regions of normal human subjects were as follows: CBF=44.4±6.5 ml/100 ml/min; CBV=3.8±0.7 ml/100 ml; OEF=0.44±0.06; CMRO2=3.3±0.5 ml/100 ml/min (11 PET centers, 70 subjects). Intrinsic regulation of cerebral circulation involves several factors. Autoregulation maintains CBF in response to changes in cerebral perfusion pressure; chemical factors such as PaCO2 affect cerebral vascular tone and alter CBF; changes in neural activity cause changes in cerebral energy metabolism and CBF; neurogenic control of CBF occurs by sympathetic innervation. Regional differences in vascular response to changes in PaCO2 have been reported, indicating regional differences in cerebral vascular tone. Relations between CBF and CBV during changes in PaCO2 and during changes in neural activity were in good agreement with Poiseuille's law. The mechanisms of vascular response to neural activation and deactivation were independent on those of responses to PaCO2 changes. CBV in a brain region is the sum of three components: arterial, capillary and venous blood volumes. It has been reported that the arterial blood volume fraction is approximately 30% in humans and that changes in human CBV during changes in PaCO2 are caused by changes in arterial blood volume without changes in venous blood volume. These findings should be considered in future studies of the pathophysiology of cerebrovascular diseases. (author) 136 refs

  9. Malaria cerebral Cerebral malaria

    Directory of Open Access Journals (Sweden)

    Carlos Hugo Zapata Zapata

    2003-03-01

    Full Text Available La malaria Cerebral (MC es la complicación más frecuente de la malaria por P. falciparum; aproximadamente el 90% de las personas que la han padecido se recuperan completamente sin secuelas neurológicas. Aún no se conoce con claridad su patogénesis pero se han postulado cuatro hipótesis o mecanismos posibles: 1 citoadherencia y secuestro de glóbulos rojos parasitados en la microvasculatura cerebral; 2 formación de rosetas y aglutinación de glóbulos rojos parasitados; 3 producción de citoquinas y activación de segundos mensajeros y, 4 apertura de la barrera hematoencefálica. Sin embargo, queda un interrogante sin resolver aún: ¿qué proceso se lleva a cabo para que el parásito, desde el espacio microvascular, pueda interferir transitoriamente con la función cerebral? Recientemente se ha utilizado el precursor de la proteína b-Amiloide como un marcador de daño neuronal en MC; este precursor será de gran ayuda en futuras investigaciones realizadas en nuestro medio que aporten información para comprender la patogénesis de la MC. Is the most common complication of P. falciparum malaria; nearly 90% of people who have suffered CM can recover without neurological problems. Currently there are four hypotheses that explain pathogenesis of CM: cytoadherence and sequestering of parasitized red blood cells to cerebral capillaries; rosette formation and parasitized red blood cells agglutination; production of cytokines and activation of second messengers and opening of the blood-brain barrier. However the main question remains to be answered; how the host-parasite interaction in the vascular space interferes transiently with cerebral function? Recently, the beta amyloid precursor peptide has been employed as marker of neural injury in CM. It is expected that the beta amyloid precursor peptide will help to understand the pathogenesis of CM in complicated patients of endemic areas of Colombia.

  10. Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms.

    Science.gov (United States)

    Varble, Nicole; Xiang, Jianping; Lin, Ning; Levy, Elad; Meng, Hui

    2016-06-01

    Recent high-resolution computational fluid dynamics (CFD) studies have detected persistent flow instability in intracranial aneurysms (IAs) that was not observed in previous in silico studies. These flow fluctuations have shown incidental association with rupture in a small aneurysm dataset. The aims of this study are to explore the capabilities and limitations of a commercial cfd solver in capturing such velocity fluctuations, whether fluctuation kinetic energy (fKE) as a marker to quantify such instability could be a potential parameter to predict aneurysm rupture, and what geometric parameters might be associated with such fluctuations. First, we confirmed that the second-order discretization schemes and high spatial and temporal resolutions are required to capture these aneurysmal flow fluctuations. Next, we analyzed 56 patient-specific middle cerebral artery (MCA) aneurysms (12 ruptured) by transient, high-resolution CFD simulations with a cycle-averaged, constant inflow boundary condition. Finally, to explore the mechanism by which such flow instabilities might arise, we investigated correlations between fKE and several aneurysm geometrical parameters. Our results show that flow instabilities were present in 8 of 56 MCA aneurysms, all of which were unruptured bifurcation aneurysms. Statistical analysis revealed that fKE could not differentiate ruptured from unruptured aneurysms. Thus, our study does not lend support to these flow instabilities (based on a cycle-averaged constant inflow as opposed to peak velocity) being a marker for rupture. We found a positive correlation between fKE and aneurysm size as well as size ratio. This suggests that the intrinsic flow instability may be associated with the breakdown of an inflow jet penetrating the aneurysm space. PMID:27109451

  11. Hyperbaric oxygen treatment induces dynamic ATPase activity changes in the rat brain following transient global cerebral ischemia-reperfusion

    Institute of Scientific and Technical Information of China (English)

    Shiming Xu; Hongjuan Wang; Tongnan Gu; Xiuyan Zhou; Rui Chen

    2008-01-01

    BACKGROUND: Energy depletion, induced by ischemia or hypoxia, is one of the first events in neuronal injury. OBJECTIVE: To investigate the dynamic changes of Na+-K+-ATPase and Ca2+-ATPase activity in the rat brain following transient global cerebral ischemia-reperfusion (IR), as well as the effects of hyperbaric oxygen (HBO) treatment. DESIGN, TIME AND SETTING: A randomized and controlled animal study was performed in the Department of Biochemistry and Molecular Biology, Capital Medical University between February and December 2006. MATERIALS: Clean-grade, female, Sprague Dawley rats were provided by the Animal Research Department of Capital Medical University (License number: SYXK11-00-0047). Na+-K+-ATPase and Ca2+-ATPase kits were provided by Nanjing Jiancheng Bioengineering Institute (Nanjing, China). A hyperbaric oxygen chamber (DWC150-300) was supplied by Shanghai 701 Medical Oxygen Chamber Factory (Shanghai, China). METHODS: Sixty-three rats were randomly divided into nine groups: sham operated group (sham-O) as control, groups of IR, and groups treated with hyperbaric oxygen (HBO) after IR. Animal from the IR and HBO groups were sacrificed after four different survival intervals of 6, 24, 48 and 96 hours, respectively. Each group consisted of seven rats. The rats of HBO groups were placed into the hyperbaric chamber. The HBO chamber was flushed with pure oxygen for 5 minutes, followed by a gradual rise in pressure over 5 minutes and stabilization at 0.2 MPa. Then, pure oxygen was supplied for 45 minutes in stabilized pressure, followed by gradually reduced pressure over 15 minutes. The rats of the 6-h HBO group were placed into the HBO chamber following reperfusion for 3 hours on the first day, which was repeated on three consecutive days, always at the same time. Rats in the sham-O group and IR group remained under normal atmospheric pressure. MAIN OUTCOME MEASURES: The Na+-K+-ATPase and Ca2+-ATPase activity in rat brain homogenate was detected by the

  12. Cerebral hemodynamics in moyamoya disease

    International Nuclear Information System (INIS)

    Rebuild-up phenomenon, an electroencephalographic pathological finding in moyamoya disease, was evaluated in the context of dynamic changes in cerebral circulation after hyperventilation. Sequential functional angiography after hyperventilation, measurement of cerebral blood flow (CBF) by the outflow method, and Kr-81m single photon emission tomography were employed for clarification of the sequential dynamic changes in cerebral circulation after hyperventilation. In most cases there was a persistent decrease in CBF even after arterial carbon dioxide tension (PaCO2) had been normalized, which suggests that the response of the cerebral circulation to the changes in PaCO2 is delayed. Moreover, this feature was most prominent in the superficial layer of the cerebrum. For the most part, coincidence and synchronization were documented between rebuild-up and the delayed response of the cerebral circulation. These findings indicate that the delayed CBF response to hyperventilation contributes pathogenetically to rebuild-up in moyamoya disease. (author)

  13. Cerebral perfusion MR imaging using FAIR-HASTE in chronic carotid occlusive disease: comparison with dynamic susceptibility contrast-perfusion MR imaging.

    Directory of Open Access Journals (Sweden)

    Ida,Kentaro

    2006-08-01

    Full Text Available To determine the efficacy of flow-sensitive alternating inversion recovery using half-Fourier single-shot turbo spin-echo (FAIR-HASTE in detecting cerebral hypoperfusion in chronic carotid occlusive disease, we subjected 12 patients with various degrees of cervical internal carotid artery stenoses and/or occlusion (Stenosis group and 24 volunteers (Normal group to FAIR-HASTE. In addition, 10 out of 12 patients in the Stenosis group underwent dynamic susceptibility contrast-perfusion magnetic resonance imaging (DSC-pMRI before and after revascularization in the dominantly affected side. The absolute asymmetry indexes (AIs of both cerebral hemispheres in the Normal and Stenosis groups were compared in FAIR-HASTE. In addition, the AIs were compared with those in the Stenosis group before and after revascularization in both FAIR-HASTE and regional cerebral blood flow (rCBF, calculated with DSC-pMRI. A statistically significant difference was recognized between the AIs in the Normal and Stenosis groups (AI = 2.25 +- 1.92, 8.09 +- 4.60, respectively ; p < 0.0001. Furthermore, in the Stenosis group the AIs on both FAIR-HASTE (8.88 +- 4.93, 2.22 +- 1.79, respectively ; p = 0.0003 and rCBF (7.13 +- 3.57, 1.25 +- 1.33, respectively ; p = 0.0003 significantly decreased after revascularization. In the Stenosis group, before revascularization, signal intensity on both FAIR-HASTE and rCBF had a tendency to be lower in the dominantly affected side. FAIR-HASTE imaging was useful in the detection and evaluation of cerebral hypoperfusion in chronic occlusive carotid disease.

  14. A simple model of cerebral blood flow dependence on arterial blood pressure

    CERN Document Server

    Gersten, Alexander

    2011-01-01

    It is shown that the dependence of the cerebral blood flow (CBF) on mean arterial blood pressure (MABP) can be described with a simple model having the following assumptions. Below certain MABP (denoted as MABP1) there are no autoregulatory or feedback mechanisms influencing CBF. Between MABP1 and MABP2 (MABP at which breakthrough accurs) there is a linear (on MABP) dependent feedback with a sloap depending very much on the individual considered. The classical autoregulation model with a plateau in between MABP1 and MABP2 is a particular case of this model. The model describes well the experiments performed on dogs (Harper 1966), for which the individual feedback sloap parameter varied to great extent, indicating the importance of mesurments on individuals against averaged mesurments (or measurments on diffent individuals) which superficially support the classical autoregulation. New effect of decreased CBF, while increasing MABP, was observed.

  15. Tuberculoma cerebral Cerebral tuberculoma

    Directory of Open Access Journals (Sweden)

    ELIZABETH CLARA BARROSO

    2002-01-01

    Full Text Available Relata-se o caso de paciente com crises convulsivas de início recente. A tomografia computadorizada cerebral evidenciou imagem sugestiva de lesão expansiva metastática frontoparietal direita. A investigação de tumor primário ou outra doença foi negativa e o exame histopatológico do tecido cerebral diagnosticou tuberculoma. As convulsões foram controladas com a associação de hidantoína 300mg/dia ao esquema específico, utilizado por 18 meses. A tuberculose do sistema nervoso central representa 5-15% das formas extrapulmonares e é reconhecida como de alta letalidade. Apresentação tumoral como a relatada é rara, particularmente em imunocompetentes. Quando tratada, pode ter bom prognóstico e deve entrar sempre no diagnóstico diferencial de massas cerebrais.It is reported a case of a previously healthy man with seizures of sudden onset. A contrast head computerized tomogram (CT showed a right frontoparietal expanding lesion suggesting to be metastatic. No prior disease was found on investigation. The histologic exam of the brain revealed tuberculoma. The seizures were controlled with Hidantoin 300 mg/day and antituberculosis chemotherapy for 18 months. Central nervous system tuberculosis (5-15% of the extrapulmonary forms is highly lethal. The case reported herein is specially rare in immunocompetent patients. It may have good prognosis and should be considered in the differential diagnosis of brain tumours.

  16. Heterogeneity of cerebral vasoreactivity in preterm infants supported by mechanical ventilation

    International Nuclear Information System (INIS)

    The reaction of cerebral blood flow to acute changes in arterial carbon dioxide pressure (PaCO2) and mean arterial blood pressure was determined in 57 preterm infants supported by mechanical ventilation (mean gestational age 30.1 weeks) during the first 48 hours of life. All infants had normal brain sonograms at the time of the investigation. In each infant, global cerebral blood flow was determined by xenon-133 clearance two to five times within a few hours at different levels of PaCO2. Changes in PaCO2 followed adjustments of the ventilator settings. Arterial oxygen pressure was intended to be kept constant, and mean arterial blood pressure fluctuated spontaneously between measurements. The data were analyzed by stepwise multiple regression, with changes in global cerebral blood flow, PaCO2, mean arterial blood pressure, and postnatal age or intracranial hemorrhage used as variables. In infants with persistently normal brain sonograms, the global cerebral blood flow-carbon dioxide reactivity was markedly lower during the first day of life (mean 11.2% to 11.8%/kPa PaCO2) compared with the second day of life (mean 32.6/kPa PaCO2), and pressure-flow autoregulation was preserved. Similarly, global cerebral blood flow-carbon dioxide reactivity and pressure-flow autoregulation were present in infants in whom mild intracranial hemorrhage developed after the study. In contrast, global cerebral blood flow reactivity to changes in PaCO2 and mean arterial blood pressure was absent in infants in whom ultrasonographic signs of severe intracranial hemorrhage subsequently developed. These infants also had about 20% lower global cerebral blood flow before hemorrhage, in comparison with infants whose sonograms were normal, a finding that suggests functional disturbances of cerebral blood flow regulation

  17. The Utility of Cerebral Blood Flow Assessment in TBI.

    Science.gov (United States)

    Akbik, Omar S; Carlson, Andrew P; Krasberg, Mark; Yonas, Howard

    2016-08-01

    Over the past few decades, intracranial monitoring technologies focused on treating and preempting secondary injury after traumatic brain injury (TBI) have experienced considerable growth. A physiological measure fundamental to the management of these patients is cerebral blood flow (CBF), which may be determined directly or indirectly. Direct measurement has proven difficult previously; however, invasive and non-invasive CBF monitors are now available. This article reviews the history of CBF measurements in TBI as well as the role of CBF in pathologies associated with TBI, such as cerebral autoregulation, hyperemia, and cortical spreading depression. The limitations of various CBF monitors are reviewed in order to better understand their role in TBI management. PMID:27315250

  18. Impaired autoregulation of the glomerular filtration rate in patients with nondiabetic nephropathies

    DEFF Research Database (Denmark)

    Christensen, P K; Hommel, E E; Clausen, P;

    1999-01-01

    BACKGROUND: The ability of the kidney to maintain constancy of the glomerular filtration rate (GFR) over a wide range of renal perfusion pressures is termed autoregulation. Defective autoregulation of GFR has been demonstrated in diabetic nephropathy. Whether this is also the case in patients...... with nondiabetic nephropathies is not known. METHODS: We investigated the effect of acute lowering of blood pressure (BP) on GFR in 16 (8 males and 8 females) albuminuric subjects suffering from different nondiabetic nephropathies and in 14 (7 males and 7 females) controls matched with respect to sex, age, BP......, and baseline GFR. The subjects received in random order an intravenous injection of either clonidine (150 to 225 microg) or saline (0.154 mmol/liter) within two weeks. We measured GFR ([51Cr]-EDTA), albuminuria (enzyme-linked immunosorbent assay; ELISA), and BP (Takeda TM-2420). RESULTS: Clonidine induced...

  19. Cerebral Palsy

    Science.gov (United States)

    ... 1 • 2 • 3 For Teens For Kids For Parents MORE ON THIS TOPIC Cerebral Palsy: Keith's Story Physical Therapy I Have Cerebral Palsy. Can I Babysit? Body Image and Self-Esteem Contact Us Print Resources Send to a friend ...

  20. Changes in cerebral blood oxygenation induced by active standing test in children with POTS and NMS.

    Science.gov (United States)

    Endo, Ayumi; Fujita, Yukihiko; Fuchigami, Tatsuo; Takahashi, Shori; Mugishima, Hideo; Skatani, Kaoru

    2014-01-01

    Orthostatic dysregulation (OD) has been classified into subtypes by heart rate and blood pressure; however, the hemodynamics of brains have not yet been revealed. Therefore, we investigated changes in cerebral blood flow and oxygenation during an active standing test to clarify the pathophysiology of two subtypes: postural tachycardia syndrome (POTS) and neurally mediated syncope (NMS). We studied 31 children (15 boys, 16 girls; mean age, 14.0 ± 1.7 years) who presented with OD at the Department of Pediatrics and Child Health, Nihon University School of Medicine between 2009 and 2011. OD was diagnosed using the Japanese clinical guidelines for juvenile orthostatic dysregulation. After a 10-min resting period in the supine position, patients were asked to quickly stand up and keep upright for 10 min. Cerebral blood flow and cerebral oxygenation were measured using transcranial Doppler sonography and near-infrared spectroscopy. POTS showed a significant decrease of oxy-Hb and resistance index (RI), suggesting transient ischemia with maintainable cerebral autoregulation. NMS showed a decrease of oxy-Hb and an increase of RI, suggesting ischemia and impairment of autoregulation.

  1. Cerebral hemodynamics in aging : the interplay between blood pressure, cerebral perfusion, and dementia

    NARCIS (Netherlands)

    Claassen, J.A.H.R.

    2008-01-01

    Advances in measurement techniques have made it possible to study dynamic changes in brain blood flow. Transcranial Doppler ultrasonography measures changes in cerebral blood flow-velocity in the larger cerebral arteries (e.g. the middle cerebral artery). Near infrared spectroscopy records changes i

  2. Elevation of D-glucose impairs coronary artery autoregulation after slight reduction of coronary flow.

    Science.gov (United States)

    Wascher, T C; Bachernegg, M; Kickenweiz, E; Stark, G; Stark, U; Toplak, H; Graier, W F; Krejs, G J

    1995-08-01

    Diabetes mellitus is thought to increase the susceptibility of tissue to hypoxic injury through D-glucose-induced alterations of intracellular metabolism. Therefore the effects of hyperglycaemia on coronary artery autoregulation under slight reduction of coronary flow were investigated in isolated perfused guinea-pig hearts. Under normal (10 mM) D-glucose concentrations coronary autoregulation was intact in response to a slight reduction of coronary flow (from 6 to 4.5 mL min-1) when L-arginine as a precursor of the endothelium-derived relaxing factor (EDRF/NO) was available and formation of prostaglandines was intact. Under high (44 mM) D-glucose concentrations on the other hand, a sustained vasodilatation dependent on the availability of L-arginine was observed, when formation of prostaglandins was blocked. This effect was partially reduced in the presence of prostaglandin synthesis. Furthermore, the effect of L-arginine under both conditions could be antagonized by the L-arginine-analogue NG-nitro-L-arginine-methyl-ester (100 microM). Our results suggest that hyperglycaemia impairs coronary artery autoregulation by reducing the threshold for hypoxic vasodilatation in an EDRF/NO-dependent manner. Concomitantly a shift from the formation of vasodilatatory to vasoconstrictive prostaglandines was observed. These results might be of particular interest in patients with diabetes mellitus and ischaemic heart disease.

  3. Cerebral palsy.

    Science.gov (United States)

    Graham, H Kerr; Rosenbaum, Peter; Paneth, Nigel; Dan, Bernard; Lin, Jean-Pierre; Damiano, Diane L; Becher, Jules G; Gaebler-Spira, Deborah; Colver, Allan; Reddihough, Dinah S; Crompton, Kylie E; Lieber, Richard L

    2016-01-01

    Cerebral palsy is the most common cause of childhood-onset, lifelong physical disability in most countries, affecting about 1 in 500 neonates with an estimated prevalence of 17 million people worldwide. Cerebral palsy is not a disease entity in the traditional sense but a clinical description of children who share features of a non-progressive brain injury or lesion acquired during the antenatal, perinatal or early postnatal period. The clinical manifestations of cerebral palsy vary greatly in the type of movement disorder, the degree of functional ability and limitation and the affected parts of the body. There is currently no cure, but progress is being made in both the prevention and the amelioration of the brain injury. For example, administration of magnesium sulfate during premature labour and cooling of high-risk infants can reduce the rate and severity of cerebral palsy. Although the disorder affects individuals throughout their lifetime, most cerebral palsy research efforts and management strategies currently focus on the needs of children. Clinical management of children with cerebral palsy is directed towards maximizing function and participation in activities and minimizing the effects of the factors that can make the condition worse, such as epilepsy, feeding challenges, hip dislocation and scoliosis. These management strategies include enhancing neurological function during early development; managing medical co-morbidities, weakness and hypertonia; using rehabilitation technologies to enhance motor function; and preventing secondary musculoskeletal problems. Meeting the needs of people with cerebral palsy in resource-poor settings is particularly challenging. PMID:27188686

  4. [Efficacy of dynamic magnetotherapy with modulation frequency 10Hz in the complex of spa rehabilitation of children with cerebral palsy].

    Science.gov (United States)

    Gurova, N Iu; Babina, L M

    2007-01-01

    Two groups of children with cerebral paralysis received combined therapy. Treatment of one of the groups included a course of magnetotherapy (AMO-ATOS unit, 10 Hz) according to the suboccipital-lumbar method, the other group was control (no magnetotherapy). The study of cliniconeurophysiological indices showed significantly higher efficacy of the therapeutic complex with a course of magnetotherapy. The highest beneficial effect was observed on bioelectrogenesis of the brain, rheoencephalographic parameters and clinical manifestation of muscular spasticity. PMID:17886367

  5. Dynamics of the brain: Mathematical models and non-invasive experimental studies

    Science.gov (United States)

    Toronov, V.; Myllylä, T.; Kiviniemi, V.; Tuchin, V. V.

    2013-10-01

    Dynamics is an essential aspect of the brain function. In this article we review theoretical models of neural and haemodynamic processes in the human brain and experimental non-invasive techniques developed to study brain functions and to measure dynamic characteristics, such as neurodynamics, neurovascular coupling, haemodynamic changes due to brain activity and autoregulation, and cerebral metabolic rate of oxygen. We focus on emerging theoretical biophysical models and experimental functional neuroimaging results, obtained mostly by functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS). We also included our current results on the effects of blood pressure variations on cerebral haemodynamics and simultaneous measurements of fast processes in the brain by near-infrared spectroscopy and a very novel functional MRI technique called magnetic resonance encephalography. Based on a rapid progress in theoretical and experimental techniques and due to the growing computational capacities and combined use of rapidly improving and emerging neuroimaging techniques we anticipate during next decade great achievements in the overall knowledge of the human brain.

  6. THE DYNAMICS OF LABILITY OF DIRECT CURRENT POTENTIALS OF THE BRAIN AND THE PSYCHOPHYSIOLOGY PARAMETERS IN THE 10-11 YEARS OLD CHILDREN WITH THE HETERO-TYPE CEREBRAL INTER-HEMISPHERES ASYMMETRY DURING SUSTAINED ATTENTION

    Directory of Open Access Journals (Sweden)

    I.A. Shimko

    2010-03-01

    Full Text Available The dynamics of direct current potentials of the brain was studied in the 10-11 years old children during sustained attention to successive presentation of series of Shulte tables. The examination was performed twice – before and after the series of training to speed reading. The gradual increase of direct current potentials during sustained attention was observed. The increase was more pronounced in the children with the left-type cerebral inter-hemispheres asymmetry, than in the children with the right-type cerebral inter-hemispheres asymmetry, moderate reaction to the loading. After the series of training to fast reading the increase of direct current potentials was reduced in both groups. This after training neurophysiological phenomenon was combined with the transformation of psychophysiological characteristics: reducing time of examination of Shulte tables and acceleration of speed of reading. It is suggested that the shifts of direct current potentials reflects the dynamics of the intensity of cerebral energy metabolism.

  7. Regulation of cerebral blood flow during exercise.

    Science.gov (United States)

    Querido, Jordan S; Sheel, A William

    2007-01-01

    Constant cerebral blood flow (CBF) is vital to human survival. Originally thought to receive steady blood flow, the brain has shown to experience increases in blood flow during exercise. Although increases have not consistently been documented, the overwhelming evidence supporting an increase may be a result of an increase in brain metabolism. While an increase in metabolism may be the underlying causative factor for the increase in CBF during exercise, there are many modulating variables. Arterial blood gas tensions, most specifically the partial pressure of carbon dioxide, strongly regulate CBF by affecting cerebral vessel diameter through changes in pH, while carbon dioxide reactivity increases from rest to exercise. Muscle mechanoreceptors may contribute to the initial increase in CBF at the onset of exercise, after which exercise-induced hyperventilation tends to decrease flow by pial vessel vasoconstriction. Although elite athletes may benefit from hyperoxia during intense exercise, cerebral tissue is well protected during exercise, and cerebral oxygenation does not appear to pose a limiting factor to exercise performance. The role of arterial blood pressure is important to the increase in CBF during exercise; however, during times of acute hypotension such as during diastole at high-intensity exercise or post-exercise hypotension, cerebral autoregulation may be impaired. The impairment of an increase in cardiac output during exercise with a large muscle mass similarly impairs the increase in CBF velocity, suggesting that cardiac output may play a key role in the CBF response to exercise. Glucose uptake and CBF do not appear to be related; however, there is growing evidence to suggest that lactate is used as a substrate when glucose levels are low. Traditionally thought to have no influence, neural innervation appears to be a protective mechanism to large increases in cardiac output. Changes in middle cerebral arterial velocity are independent of changes in

  8. Cerebral hypoxia

    Science.gov (United States)

    ... the veins ( deep vein thrombosis ) Lung infections (pneumonia) Malnutrition When to Contact a Medical Professional Cerebral hypoxia ... References Bernat JL. Coma, vegetative state, and brain death. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  9. Modelling Nephron Autoregulation and Synchronization in Coupled Nephron Systems

    DEFF Research Database (Denmark)

    Laugesen, Jakob Lund

    feedback process can explain the experimentally observed irregular oscillations in the nephron pressures and flows. The hypothesis is put to test by calculating Lyapunov exponents of a high level mechanism-based model of a nephron and a similar model of two vascular coupled nephrons. Synchronization...... between oscillating period-doubling systems is the topic of the larger part of the study. Since synchronization is a fundamental phenomenon in all sciences, it is treated from a general viewpoint by analyzing one of the most simple dynamical systems, the R¨ossler system, both in an externally forced...... version and in the form of two mutually coupled oscillators. The bifurcational mechanism to resonant dynamics and chaotic phase synchronization is described in detail. The transition from synchronized to non-synchronized dynamics is known to take place at a dense set of saddlenode bifurcations that run...

  10. Cerebral Paragonimiasis.

    Science.gov (United States)

    Miyazaki, I

    1975-01-01

    The first case of cerebral paragonimiasis was reported by Otani in Japan in 1887. This was nine years after Kerbert's discovery of the fluke in the lungs of Bengal tigers and seven years after a human pulmonary infection by the fluke was demonstrated by Baelz and Manson. The first case was a 26-year-old man who had been suffering from cough and hemosputum for one year. The patient developed convulsive seizures with subsequent coma and died. The postmortem examination showed cystic lesions in the right frontal and occipital lobes. An adult fluke was found in the occipital lesion and another was seen in a gross specimen of normal brain tissue around the affected occipital lobe. Two years after Otani's discovery, at autopsy a 29-year-old man with a history of Jacksonian seizure was reported as having cerebral paragonimiasis. Some time later, however, it was confirmed that the case was actually cerebral schistosomiasis japonica. Subsequently, cases of cerebral paragonimiasis were reported. However, the majority of these cases were not confirmed histologically. It was pointed out that some of these early cases were probably not Paragonimus infection. After World War II, reviews as well as case reports were published. Recently, investigations have been reported from Korea, with a clinicla study on 62 cases of cerebral paragonimiasis seen at the Neurology Department of the National Medical Center, Seoul, between 1958 and 1964. In 1971 Higashi described a statistical study on 105 cases of cerebral paragonimiasis that had been treated surgically in Japan.

  11. Autoregressive moving average (ARMA) model applied to quantification of cerebral blood flow using dynamic susceptibility contrast-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the feasibility of the autoregressive moving average (ARMA) model for quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in comparison with deconvolution analysis based on singular value decomposition (DA-SVD). Using computer simulations, we generated a time-dependent concentration of the contrast agent in the volume of interest (VOI) from the arterial input function (AIF) modeled as a gamma-variate function under various CBFs, cerebral blood volumes and signal-to-noise ratios (SNRs) for three different types of residue function (exponential, triangular, and box-shaped). We also considered the effects of delay and dispersion in AIF. The ARMA model and DA-SVD were used to estimate CBF values from the simulated concentration-time curves in the VOI and AIFs, and the estimated values were compared with the assumed values. We found that the CBF value estimated by the ARMA model was more sensitive to the SNR and the delay in AIF than that obtained by DA-SVD. Although the ARMA model considerably overestimated CBF at low SNRs, it estimated the CBF more accurately than did DA-SVD at high SNRs for the exponential or triangular residue function. We believe this study will contribute to an understanding of the usefulness and limitations of the ARMA model when applied to quantification of CBF with DSC-MRI. (author)

  12. Cerebral palsy - resources

    Science.gov (United States)

    Resources - cerebral palsy ... The following organizations are good resources for information on cerebral palsy : National Institute of Neurological Disorders and Stroke -- www.ninds.nih.gov/disorders/cerebral_palsy/cerebral_palsy. ...

  13. Cerebral Palsy (For Parents)

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy Cerebral Palsy KidsHealth > For Parents > Cerebral Palsy Print A A ... kids who are living with the condition. About Cerebral Palsy Cerebral palsy is one of the most common ...

  14. Absolute quantification of cerebral blood flow in neurologically normal volunteers: dynamic-susceptibility contrast MRI-perfusion compared with computed tomography (CT)-perfusion.

    Science.gov (United States)

    Ziegelitz, Doerthe; Starck, Göran; Mikkelsen, Irene K; Tullberg, Mats; Edsbagge, Mikael; Wikkelsö, Carsten; Forssell-Aronson, Eva; Holtås, Stig; Knutsson, Linda

    2009-07-01

    To improve the reproducibility of arterial input function (AIF) registration and absolute cerebral blood flow (CBF) quantification in dynamic-susceptibility MRI-perfusion (MRP) at 1.5T, we rescaled the AIF by use of a venous output function (VOF). We compared CBF estimates of 20 healthy, elderly volunteers, obtained by computed tomography (CT)-perfusion (CTP) and MRP on two consecutive days. MRP, calculated without the AIF correction, did not result in any significant correlation with CTP. The rescaled MRP showed fair to moderate correlation with CTP for the central gray matter (GM) and the whole brain. Our results indicate that the method used for correction of partial volume effects (PVEs) improves MRP experiments by reducing AIF-introduced variance at 1.5T. PMID:19253361

  15. Autoregulation of the stability operon of IncFII plasmid NR1.

    OpenAIRE

    Tabuchi, A; Min, Y N; Womble, D D; Rownd, R H

    1992-01-01

    The stb locus of IncFII plasmid NR1, which mediates stable inheritance of the plasmid, is composed of an essential cis-acting DNA site located upstream from two tandem genes that encode essential stability proteins. The two tandem genes, stbA and stbB, are transcribed as an operon from promoter PAB. Using PAB-lacZ gene fusions, it was found that the stb operon is autoregulated. A low-copy-number stb+ plasmid introduced into the same cell with the PAB-lacZ fusion plasmid repressed beta-galacto...

  16. On the efficacy of linear system analysis of renal autoregulation in rats

    DEFF Research Database (Denmark)

    Chon, K H; Chen, Y M; Holstein-Rathlou, N H;

    1993-01-01

    In order to assess the linearity of the mechanisms subserving renal blood flow autoregulation, broad-band arterial pressure fluctuations at three different power levels were induced experimentally and the resulting renal blood flow responses were recorded. Linear system analysis methods were...... experimental findings [Holstein-Rathlou et al., Amer. J. Physiol., vol. 258, 1990.]. In the time domain, impulse response functions obtained from the MA model indicated likewise the presence of these two vascular control mechanisms, but the ARMA model failed to show any vascular control mechanism at 0...

  17. Acute ischemic cerebral attack

    Directory of Open Access Journals (Sweden)

    Franco-Garcia Samir

    2010-12-01

    Full Text Available The decrease of the cerebral blood flow below the threshold of autoregulation led to changes of cerebral ischemia and necrosis that traduce in signs and symtoms of focal neurologic dysfunction called acute cerebrovascular symdrome (ACS or stroke. Two big groups according to its etiology are included in this category the hemorragic that constitue a 20% and the ischemic a 80% of cases. Great interest has wom the ischemic ACS because of its high social burden, being the third cause of no violent death in the world and the first of disability. Many risk factors favor the presentation of these events and some of them are susceptible of modification and therfore are objetives of primary prevention just as the control of diabetes, hypertension and the practice of healthy habits of life. The advances in the knowledge of the physiopatology, had taken to sustantial change in the nomenclature and management of ischemic ACS. Within these changes it was substituted the term cerebrovascular accident fo acute stroke, making emphasis in the key rol of a timely management with goals of time similiar to the acute coronary syndrome. It was redefined the time of acute ischemic attack to a one hour. Once stablished the cerebrovascular attack the semiology of symtoms with frecuency will led us make a topographic diagnosis of the in injury that joined to the cerebral TAC will allow us to exclude an hemorragic event and to start the treatment. In the management of these patients its essential the coordination of the differents teams of work, from the early recognition of symtoms on the part of patients andthe family, the rapid activation and response of emergency systems and the gearing of health care institutions. Are pillars of treatment: the abcde of reanimatiion, to avoid the hiperpirexis, the seizures, the hipoglicemy, the hiperglicemy, to achieve the thrombolysis in the first three hours of the begining of symtoms, to use antiplatelets, antithrombotic profilaxis

  18. Tuberculoma cerebral

    OpenAIRE

    BARROSO ELIZABETH CLARA; OLIVEIRA TÂNIA REGINA BRÍGIDO DE; AMARAL ANA MARIA DANTAS DO; PINHEIRO VALÉRIA GÓES FERREIRA; SOUSA ANA LÚCIA DE OLIVEIRA

    2002-01-01

    Relata-se o caso de paciente com crises convulsivas de início recente. A tomografia computadorizada cerebral evidenciou imagem sugestiva de lesão expansiva metastática frontoparietal direita. A investigação de tumor primário ou outra doença foi negativa e o exame histopatológico do tecido cerebral diagnosticou tuberculoma. As convulsões foram controladas com a associação de hidantoína 300mg/dia ao esquema específico, utilizado por 18 meses. A tuberculose do sistema nervoso central representa ...

  19. Delineation and segmentation of cerebral tumors by mapping blood-brain barrier disruption with dynamic contrast-enhanced CT and tracer kinetics modeling-a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Bisdas, S.; Vogl, T.J. [Johann Wolfgang Goethe University Hospital, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Yang, X.; Koh, T.S. [Nanyang Technological University, School of Electrical and Electronic Engineering, Nanyang (Singapore); Lim, C.C.T. [National Neuroscience Institute, Department of Neuroradiology, Singapore (Singapore); National University of Singapore, Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, Singapore (Singapore)

    2008-01-15

    Dynamic contrast-enhanced (DCE) imaging is a promising approach for in vivo assessment of tissue microcirculation. Twenty patients with clinical and routine computed tomography (CT) evidence of intracerebral neoplasm were examined with DCE-CT imaging. Using a distributed-parameter model for tracer kinetics modeling of DCE-CT data, voxel-level maps of cerebral blood flow (F), intravascular blood volume (v{sub i}) and intravascular mean transit time (t{sub 1}) were generated. Permeability-surface area product (PS), extravascular extracellular blood volume (v{sub e}) and extraction ratio (E) maps were also calculated to reveal pathologic locations of tracer extravasation, which are indicative of disruptions in the blood-brain barrier (BBB). All maps were visually assessed for quality of tumor delineation and measurement of tumor extent by two radiologists. Kappa ({kappa}) coefficients and their 95% confidence intervals (CI) were calculated to determine the interobserver agreement for each DCE-CT map. There was a substantial agreement for the tumor delineation quality in the F, v{sub e} and t{sub 1} maps. The agreement for the quality of the tumor delineation was excellent for the v{sub i}, PS and E maps. Concerning the measurement of tumor extent, excellent and nearly excellent agreement was achieved only for E and PS maps, respectively. According to these results, we performed a segmentation of the cerebral tumors on the base of the E maps. The interobserver agreement for the tumor extent quantification based on manual segmentation of tumor in the E maps vs. the computer-assisted segmentation was excellent ({kappa} = 0.96, CI: 0.93-0.99). The interobserver agreement for the tumor extent quantification based on computer segmentation in the mean images and the E maps was substantial ({kappa} = 0.52, CI: 0.42-0.59). This study illustrates the diagnostic usefulness of parametric maps associated with BBB disruption on a physiology-based approach and highlights the

  20. CRP-dependent positive autoregulation and proteolytic degradation regulate competence activator Sxy of Escherichia coli.

    Science.gov (United States)

    Jaskólska, Milena; Gerdes, Kenn

    2015-03-01

    Natural competence, the ability of bacteria to take up exogenous DNA and incorporate it into their chromosomes, is in most bacteria a transient phenomenon under complex genetic and environmental control. In the Gram-negative bacteria Haemophilus influenzae and Vibrio cholerae, the master regulator Sxy/TfoX controls competence development. Although not known to be naturally competent, Escherichia coli possesses a Sxy homologue and a competence regulon containing the genes required for DNA uptake. Here, we show that in contrast to other characterised Gamma-proteobacteria, E. coli Sxy is positively autoregulated at the level of transcription by a mechanism that requires cAMP receptor protein (CRP), cyclic AMP (cAMP) and a CRP-S site in the sxy promoter. Similarly, we found no evidence that Sxy expression in E. coli was regulated at the translational level. However, our analysis revealed that Sxy is an unstable protein and that its cellular level is negatively regulated at the post-translational level via degradation by Lon protease. Interestingly, in the Gram-positive model organism Bacillus subtilis, the competence master regulator ComK is also positively autoregulated at the level of transcription and negatively regulated by proteolysis. Together, these findings reveal striking similarities between the competence regulons of a Gram-positive and a Gram-negative bacterium.

  1. Changes in cortisol level in saliva following relaxation-activation autoregulative intervention.

    Science.gov (United States)

    Machac, M; Machacová, H; Stárka, L; Hampl, R

    1987-09-01

    The relaxation-activation autoregulative method (RAM) is a psychoregulative procedure characterized by typical autonomic patterns of relaxation and activation phases (blood pressure, electric skin resistance, heart beat, EEG, etc.). They are used as feedback information in the training of autoregulative abilities. RAM has a multidimensional (non-specific) tuning effect which is manifested by changes in the psychophysiological state (emotional tuning, physiological functioning and performance). It has a therapeutical effect on disorders with a psychic pathogenic component, e.g., essential hypertension. The increased production of adrenaline following the application of RAM was found in previous experiments.--The present experiment with a sample of six persons well mastering RAM has shown that the cortisol level following this psychoregulative intervention also rises significantly and that this rise has been recorded over three days, i.e., over the whole period of saliva sampling. It may be said that RAM has a non-specific, ergotropic (activating) subsequent effect and that this effect has the character of stress, more accurately eustress. Autogenic training, on the other hand, reduces the cortisol level.

  2. Negative and positive auto-regulation of BMP expression in early eye development.

    Science.gov (United States)

    Huang, Jie; Liu, Ying; Filas, Benjamen; Gunhaga, Lena; Beebe, David C

    2015-11-15

    Previous results have shown that Bone Morphogenetic Protein (BMP) signaling is essential for lens specification and differentiation. How BMP signals are regulated in the prospective lens ectoderm is not well defined. To address this issue we have modulated BMP activity in a chicken embryo pre-lens ectoderm explant assay, and also studied transgenic mice, in which the type I BMP receptors, Bmpr1a and Acvr1, are deleted from the prospective lens ectoderm. Our results show that chicken embryo pre-lens ectoderm cells express BMPs and require BMP signaling for lens specification in vitro, and that in vivo inhibition of BMP signals in the mouse prospective lens ectoderm interrupts lens placode formation and prevents lens invagination. Furthermore, our results provide evidence that BMP expression is negatively auto-regulated in the lens-forming ectoderm, decreasing when the tissue is exposed to exogenous BMPs and increasing when BMP signaling is prevented. In addition, eyes lacking BMP receptors in the prospective lens placode develop coloboma in the adjacent wild type optic cup. In these eyes, Bmp7 expression increases in the ventral optic cup and the normal dorsal-ventral gradient of BMP signaling in the optic cup is disrupted. Pax2 becomes undetectable and expression of Sfrp2 increases in the ventral optic cup, suggesting that increased BMP signaling alter their expression, resulting in failure to close the optic fissure. In summary, our results suggest that negative and positive auto-regulation of BMP expression is important to regulate early eye development.

  3. Cerebral Arteriosclerosis

    Science.gov (United States)

    ... the brain can cause a hemorrhagic stroke. Both types of stroke can be fatal. Cerebral arteriosclerosis is also related to a condition known as vascular dementia, in which small, symptom-free strokes cause cumulative damage and death to neurons (nerve cells) in the brain. Personality changes in ...

  4. 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

  5. Effects of Blood Pressure Fluctuations on Cerebral Perfusion after Ischemic Stroke%血压波动对脑梗死后脑灌注的影响

    Institute of Scientific and Technical Information of China (English)

    聂志余; 靳令经

    2011-01-01

    Cerebral infarction affects both cerebral autoregulation and cerebral perfusion. This review article summarizes the published evidence of cerebral autoregulation impairment and cerebral blood flow alteration after cerebral infarction, including cerebrovascular small vessel disease leading to an impairment of vasoreactivity, blood flow velocities and cerebral blood flow associated positively with systemic blood pressure, perfusion declined on the infarcted side and lower blood pressure resulting in hypoperfusion in distal area of the narrowing main cerebral artery. The question should be thought by physicians about what is the 'best blood pressure range' in patients with cerebral infarction and it will be benefit for optimal recovery.%本文主要从脑血管的自动调节与自动调节受损、脑小血管病变可导致脑血管反应性受损、脑梗死患者脑血流速度、脑血流量与血压的相关性,脑梗死侧大脑半球脑灌注降低、低血压对脑主要动脉狭窄者可导致狭窄远端脑组织局部低灌注等几个方面来讨论脑梗死后血压的变化对脑血流速度、脑血流量的影响.给临床医生提出一个思考问题,在脑梗死的急性期把血压控制在多少才是最合适的水平,对患者的功能恢复最有益.

  6. Cerebral localization in antiquity.

    Science.gov (United States)

    Rose, F Clifford

    2009-07-01

    Fragments of neurology can be found in the oldest medical writings in antiquity. Recognizable cerebral localization is seen in Egyptian medical papyri. Most notably, the Edwin Smith papyrus describes hemiplegia after a head injury. Similar echoes can be seen in Homer, the Bible, and the pre-Hippocratic writer Alcmaeon of Croton. While Biblical writers thought that the heart was the seat of the soul, Hippocratic writers located it in the head. Alexandrian anatomists described the nerves, and Galen developed the ventricular theory of cognition whereby mental functions are classified and localized in one of the cerebral ventricles. Medieval scholars, including the early Church Fathers, modified Galenic ventricular theory so as to make it a dynamic model of cognition. Physicians in antiquity subdivided the brain into separate areas and attributed to them different functions, a phenomenon that connects them with modern neurologists. PMID:20183203

  7. Estimation of intrinsic joint impedance using quasi-static passive and dynamic methods in individuals with and without Cerebral Palsy.

    Science.gov (United States)

    Androwis, Ghaith J; Michael, Peter A; Strongwater, Allan; Foulds, Richard A

    2014-01-01

    Modeling the passive behavior of the knee in subjects with spasticity involves the applied external torques (e.g. gravitational torque), the intrinsic moments due to tissue properties, as well as active, neurally defined moments resulting from the hypersensitivity of reflexes introduced by disability. In order to provide estimates of the necessary intrinsic terms in the equation of motion, the push-pull and Wartenberg Pendulum Knee Drop (PKD) tests were administered. Four subjects without disability and two subjects with Cerebral Palsy (CP) were evaluated for their active and intrinsic knee stiffness parameters. Separation of these two terms requires an additional stiffness term be added to the traditional equation of motion. This holds true for subjects with and without neurological disability. Very interestingly, the optimized non-disabled PKD produced lumped stiffness (K) that is similar to the push-pull passive stiffness (KI) for both populations. On the other hand the optimized K value in the PKD test for subjects with disability was approximately 19 times larger than the KI value found graphically from the push-pull test. This leads us to the conclusion that we can partition our lumped K as the sum of a neurally generated stiffness (Ka) and KI to complete the trajectory model. Therefore, this study shows that spasticity is a velocity dependent, that would not appear in disabled individuals unless the examined limb has a non-zero velocity.

  8. Changes in mean cerebral blood flow velocity during cognitive task-induced cerebral fatigue in high performance fighter pilots

    Institute of Scientific and Technical Information of China (English)

    Yongsheng Chen

    2008-01-01

    BACKGROUND: Several studies have demonstrated that sustained cognitive tasks can induce cognitive fatigue and that the mean cerebral blood flow velocity changes in some cerebral regions during cerebral fatigue. OBJECTIVE: To dynamically monitor the changes in mean cerebral blood flow velocity in different brain regions of high performance fighter pilots during mental arithmetic tasks and consecutive performance tasks. DESIGN, TIME AND SETTING: The present neurophysiological trial, based on controlled observation, was performed at the Laboratory of Neurophysiology, Institute of Aviation Medicine, Air Force of China between January 2003 and December 2005. PARTICIPANTS: Forty-five males, high performance fighter pilots, averaging (27.6 ± 2.5) years, were recruited for this study. METHODS: The mean cerebral blood flow velocity in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery of subjects was dynamically tested using transcranial Doppler during 5- hour mental arithmetic tasks and during 5- hour consecutive performance tasks. The neurobehavioral ability index was analyzed throughout each trial according to the number of correct responses, false responses, and lost responses. Simultaneously, cerebral cognitive fatigue-induced lethargy was assessed by the Stanford Sleepiness Scale. MAIN OUTCOME MEASURES: Changes in mean cerebral blood flow velocity in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery; neurobehavioral ability index of mental arithmetic and consecutive performance tasks; Stanford Sleepiness Scale scores. RESULTS: During mental arithmetic tasks, the mean cerebral blood flow velocity in the anterior cerebral artery increased during hour 2 and decreased after hour 4. There was no significant change in mean cerebral blood flow velocity in the middle cerebral artery and posterior cerebral artery. During hour 4, cerebral cognitive fatigue was observed and, simultaneously, Stanford Sleepiness

  9. Perfusion Pressure Cerebral Infarct (PPCI) trial - the importance of mean arterial pressure during cardiopulmonary bypass to prevent cerebral complications after cardiac surgery: study protocol for a randomised controlled trial

    DEFF Research Database (Denmark)

    Vedel, Anne G.; Holmgaard, Frederik; Rasmussen, Lars Simon;

    2016-01-01

    to be caused by emboli, but inadequate blood flow caused by other mechanisms may increase ischaemia in the penumbra or cause watershed infarcts. During cardiopulmonary bypass, blood pressure can be below the lower limit of cerebral autoregulation. Although much debated, the constant blood flow provided...... by the cardiopulmonary bypass system is still considered by many as appropriate to avoid cerebral ischaemia despite the low blood pressure. METHODS/DESIGN: The Perfusion Pressure Cerebral Infarct trial is a single-centre superiority trial with a blinded outcome assessment. The trial is randomising 210 patients...... with coronary vessel and/or valve disease and who are undergoing cardiac surgery with the use of cardiopulmonary bypass. Patients are stratified by age and surgical procedure and are randomised 1:1 to either an increased mean arterial pressure (70-80 mmHg) or 'usual practice' (40-50 mmHg) during cardiopulmonary...

  10. Cerebral hemodynamics in aging : the interplay between blood pressure, cerebral perfusion, and dementia

    OpenAIRE

    Claassen, J.A.H.R.

    2008-01-01

    Advances in measurement techniques have made it possible to study dynamic changes in brain blood flow. Transcranial Doppler ultrasonography measures changes in cerebral blood flow-velocity in the larger cerebral arteries (e.g. the middle cerebral artery). Near infrared spectroscopy records changes in brain cortical tissue concentrations of hemoglobin. These techniques are non-invasive, and can be performed with the subject in supine, sitting or standing position. Together with photoplethysmog...

  11. Employees with Cerebral Palsy

    Science.gov (United States)

    ... Resources Home | Accommodation and Compliance Series: Employees with Cerebral Palsy (CP) By Eddie Whidden, MA Preface Introduction Information ... SOAR) at http://AskJAN.org/soar. Information about Cerebral Palsy (CP) What is CP? Cerebral palsy is a ...

  12. Dynamics of cerebral tissue injury and perfusion after temporary hypoxia-ischemia in the rat - Evidence for region-specific sensitivity and delayed damage

    NARCIS (Netherlands)

    Dijkhuizen, RM; Knollema, S; van der Worp, H. Bart; Ter Horst, GJ; De Wildt, DJ; van der Sprenkel, JWB; Tulleken, KAF; Nicolay, K

    1998-01-01

    Background and Purpose-Selective regional sensitivity and delayed damage in cerebral ischemia provide opportunities for directed and late therapy for stroke. Our aim was to characterize the spatial and temporal profile of ischemia-induced changes in cerebral perfusion and tissue status, with the use

  13. Analysis of dynamic cerebral contrast-enhanced perfusion MRI time-series based on unsupervised clustering methods

    Science.gov (United States)

    Lange, Oliver; Meyer-Baese, Anke; Wismuller, Axel; Hurdal, Monica

    2005-03-01

    We employ unsupervised clustering techniques for the analysis of dynamic contrast-enhanced perfusion MRI time-series in patients with and without stroke. "Neural gas" network, fuzzy clustering based on deterministic annealing, self-organizing maps, and fuzzy c-means clustering enable self-organized data-driven segmentation w.r.t.fine-grained differences of signal amplitude and dynamics, thus identifying asymmetries and local abnormalities of brain perfusion. We conclude that clustering is a useful extension to conventional perfusion parameter maps.

  14. Controlling Spatial Heat and Light Distribution by Using Photothermal Enhancing Auto-Regulated Liposomes (PEARLs).

    Science.gov (United States)

    Ng, Kenneth K; Weersink, Robert A; Lim, Liang; Wilson, Brian C; Zheng, Gang

    2016-08-16

    Photothermal therapy (PTT) is enhanced by the use of nanoparticles with a large optical absorption at the treatment wavelength. However, this comes at the cost of higher light attenuation that results in reduced depth of heating as well as larger thermal gradients, leading to potential over- and under-treatment in the target tissue. These limitations can be overcome by using photothermal enhancing auto-regulating liposomes (PEARLs), based on thermochromic J-aggregate forming dye-lipid conjugates that reversibly alter their absorption above a predefined lipid phase-transition temperature. Under irradiation by near-infrared light, deeper layers of the target tissue revert to the intrinsic optical absorption, halting the temperature rise and enabling greater light penetration and heat generation at depth. This effect is demonstrated in both nanoparticle solutions and in gel phantoms containing the nanoparticles. PMID:27411830

  15. Synchronization among Mechanisms of Renal Autoregulation is Reduced in Hypertensive Rats

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A. N.; Mosekilde, Erik;

    2007-01-01

    We searched for synchronization among autoregulation mechanisms using wavelet transforms applied to tubular pressure recordings in nephron pairs from the surface of rat kidneys. Nephrons have two oscillatory modes in the regulation of their pressures and flows: a faster (100-200 mHz) myogenic mode......, and a slower (20-40 mHz) oscillation in tubuloglomerular feedback (TGF). These mechanisms interact; the TGF mode modulates both the amplitude and the frequency of the myogenic mode. Nephrons also communicate with each other using vascular signals triggered by membrane events in arteriolar smooth muscle cells....... In addition, the TGF oscillation changes in hypertension to an irregular fluctuation with characteristics of deterministic chaos. The analysis shows that, within single nephrons of normotensive rats, the myogenic mode and TGF are synchronized at discrete frequency ratios, with 5:1 most common...

  16. Impaired autoregulation of glomerular filtration rate in type 1 (insulin-dependent) diabetic patients with nephropathy

    DEFF Research Database (Denmark)

    Parving, H H; Kastrup, Helge; Smidt, U M;

    1984-01-01

    served as controls. Renal function was assessed by glomerular filtration rate (single bolus 51Cr-EDTA technique) and urinary albumin excretion rate (radial immunodiffusion). The study was performed twice within 2 weeks, with the subjects receiving an intravenous injection of either clonidine (225...... arterial blood pressure in all three groups (16-18 mmHg). While glomerular filtration rate and urinary albumin excretion rate remained unchanged in both control groups after clonidine injection, glomerular filtration rate diminished from 78 to 71 ml/min per 1.73 m2 (p les than 0.01), and urinary albumin...... excretion declined from 1707 to 938 micrograms/min (p less than 0.01) in the patients with diabetic nephropathy. Our results suggest that an intrinsic vascular (arteriolar) mechanism underlying the normal autoregulation of glomerular filtration rate, i.e. the relative constancy of glomerular filtration rate...

  17. Analysis of interaction between TGF and the myogenic response in renal blood flow autoregulation

    DEFF Research Database (Denmark)

    Feldberg, R; Colding-Jørgensen, M; Holstein-Rathlou, N H

    1995-01-01

    The present study investigates the interaction between the tubuloglomerular feedback (TGF) response and the myogenic mechanism by use of a mathematical model. The two control mechanisms are implemented in a spatially distributed model of the rat renal juxtamedullary afferent arteriole. The model....... The contribution of TGF to smooth muscle activity is assumed to be a linear function of the glomerular capillary pressure. The results show that the myogenic response plays an important role in renal blood flow autoregulation. Without a myogenic response, mechanisms such as TGF that are localized in the distal...... located in the distal part of the afferent arteriole. An ascending myogenic response could enhance the regulatory efficiency of the TGF mechanism by increasing the open-loop gain of the system. However, such a synergistic interaction will only be observed when the two mechanisms operate on more or less...

  18. Cerebral oxygenation and hyperthermia

    Directory of Open Access Journals (Sweden)

    Anthony Richard Bain

    2014-03-01

    Full Text Available Hyperthermia is associated with marked reductions in cerebral blood flow (CBF. Increased distribution of cardiac output to the periphery, increases in alveolar ventilation and resultant hypocapnia each contribute to the fall in CBF during passive hyperthermia; however, their relative contribution remains a point of contention, and probably depends on the experimental condition (e.g. posture and degree of hyperthermia. The hyperthermia-induced hyperventilatory response reduces arterial CO2 pressure (PaCO2 causing cerebral vasoconstriction and subsequent reductions in flow. During supine passive hyperthermia, the majority of recent data indicate that reductions in PaCO2 may be the primary, if not sole, culprit for reduced CBF. On the other hand, during more dynamic conditions (e.g. hemorrhage or orthostatic challenges, an inability to appropriately decrease peripheral vascular conductance presents a condition whereby adequate cerebral perfusion pressure may be compromised secondary to reductions in systemic blood pressure. Although studies have reported maintenance of pre-frontal cortex oxygenation (assessed by near-infrared spectroscopy during exercise and severe heat stress, the influence of cutaneous blood flow is known to contaminate this measure. This review discusses the governing mechanisms associated with changes in CBF and oxygenation during moderate to severe (i.e. 1.0°C to 2.0°C increase in body core temperature levels of hyperthermia. Future research directions are provided.

  19. Hepatic autoregulation

    DEFF Research Database (Denmark)

    Staehr, Peter; Hother-Nielsen, Ole; Beck-Nielsen, Henning;

    2007-01-01

    The effect of increased glycogenolysis, simulated by galactose's conversion to glucose, on the contribution of gluconeogenesis (GNG) to hepatic glucose production (GP) was determined. The conversion of galactose to glucose is by the same pathway as glycogen's conversion to glucose, i.e., glucose 1...

  20. Analytic Models of Oxygen and Nutrient Diffusion, Metabolism Dynamics, and Architecture Optimization in Three-Dimensional Tissue Constructs with Applications and Insights in Cerebral Organoids.

    Science.gov (United States)

    McMurtrey, Richard J

    2016-03-01

    Diffusion models are important in tissue engineering as they enable an understanding of gas, nutrient, and signaling molecule delivery to cells in cell cultures and tissue constructs. As three-dimensional (3D) tissue constructs become larger, more intricate, and more clinically applicable, it will be essential to understand internal dynamics and signaling molecule concentrations throughout the tissue and whether cells are receiving appropriate nutrient delivery. Diffusion characteristics present a significant limitation in many engineered tissues, particularly for avascular tissues and for cells whose viability, differentiation, or function are affected by concentrations of oxygen and nutrients. This article seeks to provide novel analytic solutions for certain cases of steady-state and nonsteady-state diffusion and metabolism in basic 3D construct designs (planar, cylindrical, and spherical forms), solutions that would otherwise require mathematical approximations achieved through numerical methods. This model is applied to cerebral organoids, where it is shown that limitations in diffusion and organoid size can be partially overcome by localizing metabolically active cells to an outer layer in a sphere, a regionalization process that is known to occur through neuroglial precursor migration both in organoids and in early brain development. The given prototypical solutions include a review of metabolic information for many cell types and can be broadly applied to many forms of tissue constructs. This work enables researchers to model oxygen and nutrient delivery to cells, predict cell viability, study dynamics of mass transport in 3D tissue constructs, design constructs with improved diffusion capabilities, and accurately control molecular concentrations in tissue constructs that may be used in studying models of development and disease or for conditioning cells to enhance survival after insults like ischemia or implantation into the body, thereby providing a

  1. Cerebral palsy

    International Nuclear Information System (INIS)

    This paper reviews cranial MR findings in patients with cerebral palsy (CP) to clarify and categorize this disorder. The MR images of 40 patients with clinical CP were retrospectively reviewed. All patients suffered either varying spastic plegias, hypotonicity, or choreoathetosis. Concomitantly, the patients suffered from static encephalopathy, developmental delay, and/or microcephaly. Twenty-four patients were born at or near term, 10 were premature, and incomplete birth histories were available in six. The MR images revealed mild to severe degrees of white matter damage in 24 patients (12 term, nine premature, three unknown)

  2. In-vivo optical imaging and spectroscopy of cerebral hemodynamics

    Science.gov (United States)

    Zhou, Chao

    Functional optical imaging techniques, such as diffuse optical imaging and spectroscopy and laser speckle imaging (LSI), were used in research and clinical settings to measure cerebral hemodynamics. In this thesis, theoretical and experimental developments of the techniques and their in-vivo applications ranging from small animals to adult humans are demonstrated. Near infrared diffuse optical techniques non-invasively measure hemoglobin concentrations, blood oxygen saturation (diffuse reflectance spectroscopy, DRS) and blood flow (diffuse correlation spectroscopy, DCS) in deep tissues, e.g. brain. A noise model was derived for DCS measurements. Cerebral blood flow (CBF) measured with DCS was validated with arterial-spin-labeling MRI. Three-dimensional CBF tomography was obtained during cortical spreading depression from a rat using the optimized diffuse correlation tomographic method. Cerebral hemodynamics in newborn piglets after traumatic brain injury were continuously monitored optically for six hours to demonstrate the feasibility of using diffuse optical techniques as bedside patient monitors. Cerebral autoregulation in piglets and human stroke patients was demonstrated to be non-invasively assessable via the continuous DCS measurement. Significant differences of CBF responses to head-of-bead maneuvers were observed between the peri- and contra-infarct hemispheres in human stroke patients. A significant portion of patient population showed paradoxical CBF responses, indicating the importance of individualized stroke management. The development of a speckle noise model revealed the source of noise for LSI. LSI was then applied to study the acute functional recovery of the rat brain following transient brain ischemia. The spatial and temporal cerebral blood flow responses to functional stimulation were statistically quantified. The area of activation, and the temporal response to stimulation were found significantly altered by the ischemic insult, while the

  3. EFFECT OF LEFT VENTRICULAR SYSTOLIC DYSFUNCTION ON CEREBRAL HEMODYNAMICS IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION (THE RESULTS OF OBSERVATIONAL STUDIES

    Directory of Open Access Journals (Sweden)

    V. E. Kulikov

    2015-12-01

    Full Text Available Aim. To study the effect of left ventricular (LV systolic dysfunction on cerebral hemodynamic in patients with ST segment elevation myocardial infarction (STEMI during acute period. Material and methods. Cerebral hemodynamics ultrasound assessment was performed in the extra-and intracranial vessels in 118 patients with STEMI. Results. Significant changes in cerebral hemodynamics were found in LV systolic dysfunction with ejection fraction (LVEF ≤40% due to hemispheric blood flow asymmetry in the middle cerebral artery (MCA as large as 45.1±6.7% with correlation coefficient r=-0.87. Compensation of cerebral blood flow was manifested in vasoconstriction or vasodilation (resistive index 0.63-0.76 and 0.49-0.43 c.u., respectively. Conclusion. A strong relationship between LV systolic dysfunction and cerebral hemodynamic was found in patients with STEMI. It was manifested in significant contralateral hemispheric blood flow asymmetry in MCA in patients with LVEF ≤40%. Reduction in cerebral blood flow velocity activated autoregulation mechanism in the form of vasoconstriction or vasodilation.

  4. Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilaterial cerebrovascular disease: concise communication

    International Nuclear Information System (INIS)

    To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density in TCT. In reversible episodes, sensitivity of AF alone was significantly below the sensitivity of combined evaluation of flow and ratio

  5. Cerebral malaria.

    Science.gov (United States)

    Postels, Douglas G; Birbeck, Gretchen L

    2013-01-01

    Malaria, the most significant parasitic disease of man, kills approximately one million people per year. Half of these deaths occur in those with cerebral malaria (CM). The World Health Organization (WHO) defines CM as an otherwise unexplained coma in a patient with malarial parasitemia. Worldwide, CM occurs primarily in African children and Asian adults, with the vast majority (greater than 90%) of cases occurring in children 5 years old or younger in sub-Saharan Africa. The pathophysiology of the disease is complex and involves infected erythrocyte sequestration, cerebral inflammation, and breakdown of the blood-brain barrier. A recently characterized malarial retinopathy is visual evidence of Plasmodium falciparum's pathophysiological processes occurring in the affected patient. Treatment consists of supportive care and antimalarial administration. Thus far, adjuvant therapies have not been shown to improve mortality rates or neurological outcomes in children with CM. For those who survive CM, residual neurological abnormalities are common. Epilepsy, cognitive impairment, behavioral disorders, and gross neurological deficits which include motor, sensory, and language impairments are frequent sequelae. Primary prevention strategies, including bed nets, vaccine development, and chemoprophylaxis, are in varied states of development and implementation. Continuing efforts to find successful primary prevention options and strategies to decrease neurological sequelae are needed. PMID:23829902

  6. Differences in dynamic autoregulation of renal blood flow between SHR and WKY rats

    DEFF Research Database (Denmark)

    Chen, Y M; Holstein-Rathlou, N H

    1993-01-01

    In halothane-anesthetized Wistar-Kyoto (WKY) rats the single-nephron blood flow and the proximal tubule pressure oscillate at a frequency of 35-50 mHz because of the operation of the tubuloglomerular feedback (TGF) mechanism. In spontaneously hypertensive rats (SHR) the oscillations are replaced...... response of renal vascular admittance was estimated by the method of autoregressive-moving averages. In the frequency band below 60-70 mHz there was a significant difference in the transfer functions between the two strains of rats. This was due mainly to an increased phase difference, but also...... to a decreased magnitude of the admittance in SHR at frequencies below 20-30 mHz. Above 70 mHz there was no significant difference in the transfer functions. Because TGF is active in the low frequency band (below approximately 100 mHz), whereas the myogenic mechanism also acts in the higher frequency band, we...

  7. Thyroglobulin in smoking mothers and their newborns at delivery suggests autoregulation of placental iodide transport overcoming thiocyanate inhibition

    DEFF Research Database (Denmark)

    Andersen, Stine L; Backman Nøhr, Susanne; Wu, Chun S;

    2013-01-01

    ). The pregnant women reported on intake of iodine-containing supplements during pregnancy and Tg in maternal serum at delivery and in cord serum were analyzed. RESULTS: In a context of mild-to-moderate iodine deficiency, smoking mothers had significantly higher serum Tg than nonsmoking mothers (mean Tg smokers...... maternal smoking, but compensatory autoregulation of iodide transport differs between organs. The extent of autoregulation of placental iodide transport remains to be clarified. OBJECTIVE: To compare the impact of maternal smoking on thyroglobulin (Tg) levels in maternal serum at delivery and in cord serum...... as markers of maternal and fetal iodine deficiency. METHODS: One hundred and forty healthy, pregnant women admitted for delivery and their newborns were studied before the iodine fortification of salt in Denmark. Cotinine in urine and serum classified mothers as smokers (n=50) or nonsmokers (n=90...

  8. Cerebral venous thrombosis in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M.; Martin, E.; Willi, U.V. [Dept. of Diagnostic Imaging and Radiology, University Children' s Hospital Zurich (Switzerland); Holzmann, D. [Dept. of Otorhinolaryngology, University Children' s Hospital Zurich, Zurich (Switzerland)

    2001-09-01

    This was a retrospective study to determine different etiologies of cerebral venous thrombosis (CVT) in childhood and to correlate extent and location of thrombosis with the etiology and the age of the child as well as the final outcome. In addition, the radiologic approach is discussed. This was a retrospective analysis of 19 children with CVT. The children were examined by contrast-enhanced dynamic CT. Radiologic findings were correlated with the etiology of CVT. Cerebral venous thrombosis is not as infrequent in children as has been thought. Cerebral venous thrombosis in children can occur due to trauma (n=9), infections (n=7), or coagulation disorders (n=3). Extent and location of thrombosis, as well as complications, final outcome, and therapy, depend on the etiology. Computed tomography remains a valuable primary imaging modality in the diagnosis of CVT in the acutely injured or diseased child. (orig.)

  9. Cerebral venous thrombosis in childhood

    International Nuclear Information System (INIS)

    This was a retrospective study to determine different etiologies of cerebral venous thrombosis (CVT) in childhood and to correlate extent and location of thrombosis with the etiology and the age of the child as well as the final outcome. In addition, the radiologic approach is discussed. This was a retrospective analysis of 19 children with CVT. The children were examined by contrast-enhanced dynamic CT. Radiologic findings were correlated with the etiology of CVT. Cerebral venous thrombosis is not as infrequent in children as has been thought. Cerebral venous thrombosis in children can occur due to trauma (n=9), infections (n=7), or coagulation disorders (n=3). Extent and location of thrombosis, as well as complications, final outcome, and therapy, depend on the etiology. Computed tomography remains a valuable primary imaging modality in the diagnosis of CVT in the acutely injured or diseased child. (orig.)

  10. Non-ionizing radiofrequency electromagnetic waves traversing the head can be used to detect cerebrovascular autoregulation responses

    OpenAIRE

    Oziel, M.; M. Hjouj; Gonzalez, C.A.; Lavee, J.; Rubinsky, B

    2016-01-01

    Monitoring changes in non-ionizing radiofrequency electromagnetic waves as they traverse the brain can detect the effects of stimuli employed in cerebrovascular autoregulation (CVA) tests on the brain, without contact and in real time. CVA is a physiological phenomenon of importance to health, used for diagnosis of a number of diseases of the brain with a vascular component. The technology described here is being developed for use in diagnosis of injuries and diseases of the brain in rural an...

  11. A phosphatidylinositol lipids system, lamellipodin, and Ena/VASP regulate dynamic morphology of multipolar migrating cells in the developing cerebral cortex.

    Science.gov (United States)

    Yoshinaga, Satoshi; Ohkubo, Takahiro; Sasaki, Shinji; Nuriya, Mutsuo; Ogawa, Yukino; Yasui, Masato; Tabata, Hidenori; Nakajima, Kazunori

    2012-08-22

    In the developing mammalian cerebral cortex, excitatory neurons are generated in the ventricular zone (VZ) and subventricular zone; these neurons migrate toward the pial surface. The neurons generated in the VZ assume a multipolar morphology and remain in a narrow region called the multipolar cell accumulation zone (MAZ) for ∼24 h, in which they extend and retract multiple processes dynamically. They eventually extend an axon tangentially and begin radial migration using a migratory mode called locomotion. Despite the potential biological importance of the process movement of multipolar cells, the molecular mechanisms remain to be elucidated. Here, we observed that the processes of mouse multipolar cells were actin rich and morphologically resembled the filopodia and lamellipodia in growth cones; thus, we focused on the actin-remodeling proteins Lamellipodin (Lpd) and Ena/vasodilator-stimulated phosphoprotein (VASP). Lpd binds to phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P₂] and recruits Ena/VASP, which promotes the assembly of actin filaments, to the plasma membranes. In situ hybridization and immunohistochemistry revealed that Lpd is expressed in multipolar cells in the MAZ. The functional silencing of either Lpd or Ena/VASP decreased the number of primary processes. Immunostaining and a Förster resonance energy transfer analysis revealed the subcellular localization of PI(3,4)P₂ at the tips of the processes. A knockdown experiment and treatment with an inhibitor for Src homology 2-containing inositol phosphatase-2, a 5-phosphatase that produces PI(3,4)P₂ from phosphatidylinositol (3,4,5)-triphosphate, decreased the number of primary processes. Our observations suggest that PI(3,4)P₂, Lpd, and Ena/VASP are involved in the process movement of multipolar migrating cells.

  12. Cerebral cysticercosis

    International Nuclear Information System (INIS)

    Two cases of histologically proven cerebral cysticercosis are presented. In both cases subcutaneous tissue nodules, a rare feature, were present. Several disease patterns are apparent - meningeal, parenchymatous and ventricular, spinal cord lesions and mixed patterns. Epilepsy is by far the major presenting symptom of cysticercosis, which in turn plays a significant role in the causation of adult-onset epilepsy in Blacks. Despite its drawbacks, the haemag-glutination inhibition test remains the most satisfactory serological method at present available for the diagnosis of cysticercosis; it is positive in up to 85% of cases of proven cysticercosis. With the advent of computed tomography many cases of unsuspected cysticercosis (symptomatic or asymptomatic) are being discovered

  13. Investigating cerebral oedema using poroelasticity.

    Science.gov (United States)

    Vardakis, John C; Chou, Dean; Tully, Brett J; Hung, Chang C; Lee, Tsong H; Tsui, Po-Hsiang; Ventikos, Yiannis

    2016-01-01

    Cerebral oedema can be classified as the tangible swelling produced by expansion of the interstitial fluid volume. Hydrocephalus can be succinctly described as the abnormal accumulation of cerebrospinal fluid (CSF) within the brain which ultimately leads to oedema within specific sites of parenchymal tissue. Using hydrocephalus as a test bed, one is able to account for the necessary mechanisms involved in the interaction between oedema formation and cerebral fluid production, transport and drainage. The current state of knowledge about integrative cerebral dynamics and transport phenomena indicates that poroelastic theory may provide a suitable framework to better understand various diseases. In this work, Multiple-Network Poroelastic Theory (MPET) is used to develop a novel spatio-temporal model of fluid regulation and tissue displacement within the various scales of the cerebral environment. The model is applied through two formats, a one-dimensional finite difference - Computational Fluid Dynamics (CFD) coupling framework, as well as a two-dimensional Finite Element Method (FEM) formulation. These are used to investigate the role of endoscopic fourth ventriculostomy in alleviating oedema formation due to fourth ventricle outlet obstruction (1D coupled model) in addition to observing the capability of the FEM template in capturing important characteristics allied to oedema formation, like for instance in the periventricular region (2D model). PMID:26749338

  14. Cerebral blood volume calculated by dynamic susceptibility contrast-enhanced perfusion MR imaging: preliminary correlation study with glioblastoma genetic profiles.

    Directory of Open Access Journals (Sweden)

    Inseon Ryoo

    Full Text Available PURPOSE: To evaluate the usefulness of dynamic susceptibility contrast (DSC enhanced perfusion MR imaging in predicting major genetic alterations in glioblastomas. MATERIALS AND METHODS: Twenty-five patients (M:F = 13∶12, mean age: 52.1±15.2 years with pathologically proven glioblastoma who underwent DSC MR imaging before surgery were included. On DSC MR imaging, the normalized relative tumor blood volume (nTBV of the enhancing solid portion of each tumor was calculated by using dedicated software (Nordic TumorEX, NordicNeuroLab, Bergen, Norway that enabled semi-automatic segmentation for each tumor. Five major glioblastoma genetic alterations (epidermal growth factor receptor (EGFR, phosphatase and tensin homologue (PTEN, Ki-67, O6-methylguanine-DNA methyltransferase (MGMT and p53 were confirmed by immunohistochemistry and analyzed for correlation with the nTBV of each tumor. Statistical analysis was performed using the unpaired Student t test, ROC (receiver operating characteristic curve analysis and Pearson correlation analysis. RESULTS: The nTBVs of the MGMT methylation-negative group (mean 9.5±7.5 were significantly higher than those of the MGMT methylation-positive group (mean 5.4±1.8 (p = .046. In the analysis of EGFR expression-positive group, the nTBVs of the subgroup with loss of PTEN gene expression (mean: 10.3±8.1 were also significantly higher than those of the subgroup without loss of PTEN gene expression (mean: 5.6±2.3 (p = .046. Ki-67 labeling index indicated significant positive correlation with the nTBV of the tumor (p = .01. CONCLUSION: We found that glioblastomas with aggressive genetic alterations tended to have a high nTBV in the present study. Thus, we believe that DSC-enhanced perfusion MR imaging could be helpful in predicting genetic alterations that are crucial in predicting the prognosis of and selecting tailored treatment for glioblastoma patients.

  15. XRN2 Autoregulation and Control of Polycistronic Gene Expresssion in Caenorhabditis elegans

    Science.gov (United States)

    2016-01-01

    XRN2 is a conserved 5’→3’ exoribonuclease that complexes with proteins that contain XRN2-binding domains (XTBDs). In Caenorhabditis elegans (C. elegans), the XTBD-protein PAXT-1 stabilizes XRN2 to retain its activity. XRN2 activity is also promoted by 3'(2'),5'-bisphosphate nucleotidase 1 (BPNT1) through hydrolysis of an endogenous XRN inhibitor 3’-phosphoadenosine-5'-phosphate (PAP). Here, we find through unbiased screening that loss of bpnt-1 function suppresses lethality caused by paxt-1 deletion. This unexpected finding is explained by XRN2 autoregulation, which occurs through repression of a cryptic promoter activity and destabilization of the xrn-2 transcript. De-repression appears to be triggered such that more robust XRN2 perturbation, by elimination of both PAXT-1 and BPNT1, is less detrimental to worm viability than absence of PAXT-1 alone. Indeed, we find that two distinct XRN2 repression mechanisms are alleviated at different thresholds of XRN2 inactivation. Like more than 15% of C. elegans genes, xrn-2 occurs in an operon, and we identify additional operons under its control, consistent with a broader function of XRN2 in polycistronic gene regulation. Regulation occurs through intercistronic regions that link genes in an operon, but a part of the mechanisms may allow XRN2 to operate on monocistronic genes in organisms lacking operons. PMID:27631780

  16. XRN2 Autoregulation and Control of Polycistronic Gene Expresssion in Caenorhabditis elegans.

    Science.gov (United States)

    Miki, Takashi S; Carl, Sarah H; Stadler, Michael B; Großhans, Helge

    2016-09-01

    XRN2 is a conserved 5'→3' exoribonuclease that complexes with proteins that contain XRN2-binding domains (XTBDs). In Caenorhabditis elegans (C. elegans), the XTBD-protein PAXT-1 stabilizes XRN2 to retain its activity. XRN2 activity is also promoted by 3'(2'),5'-bisphosphate nucleotidase 1 (BPNT1) through hydrolysis of an endogenous XRN inhibitor 3'-phosphoadenosine-5'-phosphate (PAP). Here, we find through unbiased screening that loss of bpnt-1 function suppresses lethality caused by paxt-1 deletion. This unexpected finding is explained by XRN2 autoregulation, which occurs through repression of a cryptic promoter activity and destabilization of the xrn-2 transcript. De-repression appears to be triggered such that more robust XRN2 perturbation, by elimination of both PAXT-1 and BPNT1, is less detrimental to worm viability than absence of PAXT-1 alone. Indeed, we find that two distinct XRN2 repression mechanisms are alleviated at different thresholds of XRN2 inactivation. Like more than 15% of C. elegans genes, xrn-2 occurs in an operon, and we identify additional operons under its control, consistent with a broader function of XRN2 in polycistronic gene regulation. Regulation occurs through intercistronic regions that link genes in an operon, but a part of the mechanisms may allow XRN2 to operate on monocistronic genes in organisms lacking operons.

  17. Cerebral cartography and connectomics.

    Science.gov (United States)

    Sporns, Olaf

    2015-05-19

    Cerebral cartography and connectomics pursue similar goals in attempting to create maps that can inform our understanding of the structural and functional organization of the cortex. Connectome maps explicitly aim at representing the brain as a complex network, a collection of nodes and their interconnecting edges. This article reflects on some of the challenges that currently arise in the intersection of cerebral cartography and connectomics. Principal challenges concern the temporal dynamics of functional brain connectivity, the definition of areal parcellations and their hierarchical organization into large-scale networks, the extension of whole-brain connectivity to cellular-scale networks, and the mapping of structure/function relations in empirical recordings and computational models. Successfully addressing these challenges will require extensions of methods and tools from network science to the mapping and analysis of human brain connectivity data. The emerging view that the brain is more than a collection of areas, but is fundamentally operating as a complex networked system, will continue to drive the creation of ever more detailed and multi-modal network maps as tools for on-going exploration and discovery in human connectomics.

  18. United Cerebral Palsy

    Science.gov (United States)

    ... be sure to follow us on Twitter . United Cerebral Palsy UCP educates, advocates and provides support services to ... Partners Merz Logo Sprint Relay Copyright © 2015 United Cerebral Palsy 1825 K Street NW Suite 600 Washington, DC ...

  19. Propofol effect on cerebral oxygenation in children with congenital heart disease.

    Science.gov (United States)

    Fleck, Thilo; Schubert, Stephan; Ewert, Peter; Stiller, Brigitte; Nagdyman, Nicole; Berger, Felix

    2015-03-01

    Propofol is a short-acting, intravenously administered hypnotic agent which is used in procedural sedation in children. Propofol is known to decrease systemic vascular resistance, arterial blood pressure and can lead to desaturations and decreased systemic perfusion in children with cardiac shunting. This may result in a reduction in cerebral blood flow and oxygenation. Near-infrared spectroscopy (NIRS) can monitor cerebral tissue oxygenation in the frontal neocortex. The objective of our study was to measure the changes in cerebral oxygen and blood supply after Propofol infusion in children with congenital heart disease. Propofol infusion may reduce cerebral oxygenation in children with congenital heart disease. The study group consisted of 32 children (f:m = 18:14), with median age of 49 (5-112) months and median weight of 15 (5-34) kg. We performed NIRS derived continuous measurement of cerebral oxygenation and cardiac output using Electrical velocimetry for 5 min before and after sedation with Propofol (1-2 mg/kg i.v.) for cardiac catheterization. Simultaneously, non-invasive arterial blood pressure and transcutaneous oxygen saturation were measured. Propofol sedation led to a significant decrease in mean arterial pressure (79 ± 16 vs. 67 ± 12 mmHg) (p = 0.01) and cardiac index (3.2 ± 0.8 vs. 2.9 ± 0.6 ml/min/m(2)) (p = 0.03). In contrast, cerebral tissue oxygenation index, increased significantly from 57 ± 11 to 59 ± 10 % (p blood pressure. This may be caused by a decreased oxygen consumption of the sedated brain with intact cerebral auto-regulation. PMID:25311762

  20. Cerebral palsy and epilepsy

    OpenAIRE

    Knežević-Pogančev Marija

    2010-01-01

    Introduction. Cerebral palsy is the most common cause of physical disability in early childhood. Epilepsy is known to have a high association with cerebral palsy. All types of epileptic seizures can be seen in patients with cerebral palsy. Complex partial and secondary generalized ones are the most frequent seizure types. In persons with cerebral palsy and mental retardation, the diagnosis of epilepsy presents unique difficulties. Generally they are not able to describe the epileptic ev...

  1. The effect of herbs on cerebral energy metabolism in cerebral ischemia-reperfusion mice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Vascular dementia is one of the most familiar types of senile dementia. Over the past few years, the research on the damage of cerebral tissues after ischemia has become a focus. The factors and mechanism of cerebral tissue damage after ischemia are very complex. The handicap of energy metabolism is regarded as the beginning factor which leads to the damage of neurons, but its dynamic changes in ischemic area and its role during the process of neuronal damage are not very clear. There are few civil reports on using 31 P nuclear magnetic resonance instrument to explore the changes of cerebral energy metabolism in intravital animals. After exploring the influence of herbs on cerebral energy metabolism in ischemia-reperfusion mice, we came to the conclusion that herbs can improve the cerebral energy metabolism in ischemia-reperfusion mice.

  2. The effects of healthy aging on cerebral hemodynamic responses to posture change

    International Nuclear Information System (INIS)

    Aging is associated with an increased incidence of orthostatic hypotension, impairment of the baroreceptor reflex and lower baseline cerebral blood flow. The effect of aging on cerebrovascular autoregulation, however, remains to be fully elucidated. We used a novel optical instrument to assess microvascular cerebral hemodynamics in the frontal lobe cortex of 60 healthy subjects ranging from ages 20–78. Diffuse correlation spectroscopy (DCS) and near-infrared spectroscopy (NIRS) were used to measure relative cerebral blood flow (rCBF), total hemoglobin concentration (THC), oxyhemoglobin concentration (HbO2) and deoxyhemoglobin concentration (Hb). Cerebral hemodynamics were monitored for 5 min at each of the following postures: head-of-bed 30°, supine, standing and supine. Supine-to-standing posture change caused significant declines in rCBF, THC and HbO2, and an increase in Hb, across the age continuum (p < 0.01). Healthy aging did not alter postural changes in frontal cortical rCBF (p = 0.23) and was associated with a smaller magnitude of decline in HbO2 (p < 0.05) during supine-to-standing posture change. We conclude that healthy aging does not alter postural changes in frontal cortical perfusion

  3. Impaired autoregulation of blood flow in subcutaneous tissue of long-term type 1 (insulin-dependent) diabetic patients with microangiopathy

    DEFF Research Database (Denmark)

    Kastrup, J; Nørgaard, T; Parving, H H;

    1985-01-01

    Autoregulation of blood flow in subcutaneous tissue was studied at the level of the lateral malleolus in eight long-term Type 1 (insulin-dependent) diabetic patients with clinical microangiopathy, eight short-term Type 1 diabetic patients without clinical microangiopathy and seven healthy control...... by activation of the leg muscle vein pump (heel raising). Mean arterial blood pressure was thus varied between 60 and 160 mmHg. In normal and short-term diabetic subjects blood flow remained within 10% of control values during the changes in arterial blood pressure. In six of the eight Type 1 diabetic patients...... with clinical microangiopathy, autoregulation of blood flow was impaired, blood flow changing approximately 20% per 10 mmHg change in arterial blood pressure; the slope of the autoregulation curves was significantly higher compared with the two control groups (p less than 0.02). Resting mean arterial blood...

  4. Spectral analysis of systemic and cerebral cardiovascular variabilities in preterm infants: relationship with clinical risk index for babies (CRIB)

    International Nuclear Information System (INIS)

    Frequency spectrum analysis of circulatory signals has been proposed as a potential method for clinical risk assessment of preterm infants by previous studies. In this study, we examined the relationships between various spectral measures derived from systemic and cerebral cardiovascular variabilities and the clinical risk index for babies (CRIB II). Physiological data collected from 17 early low birth weight infants within 1–3 h after birth were analysed. Spectral and cross-spectral analyses were performed on heart rate variability, blood pressure variability and cerebral near-infrared spectroscopy measures such as oxygenated and deoxygenated haemoglobins (HbO2 and HHb) and tissue oxygenation index (TOI). In addition, indices related to cardiac baroreflex sensitivity and cerebral autoregulation were derived from the very low, low- and mid-frequency ranges (VLF, LF and MF). Moderate correlations with CRIB II were identified from mean arterial pressure (MAP) normalized MF power (r = 0.61, P = 0.009), LF MAP–HHb coherence (r = 0.64, P = 0.006), TOI VLF percentage power (r = 0.55, P = 0.023) and LF baroreflex gain (r = −0.61, P = 0.01 after logarithmic transformation), with the latter two parameters also highly correlated with gestational age (r = −0.75, P = 0.0005 and r = 0.70, P = 0.002, respectively). The relationships between CRIB II and various spectral measures of arterial baroreflex and cerebral autoregulation functions have provided further justification for these measures as possible markers of clinical risks and predictors of adverse outcome in preterm infants

  5. Cerebral microangiopathies; Zerebrale Mikroangiopathien

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Jennifer [Klinikum der Universitaet Muenchen (Germany). Abt. fuer Neuroradiologie

    2011-03-15

    Cerebral microangiopathies are a very heterogenous group of diseases characterized by pathological changes of the small cerebral vessels. They account for 20 - 30 % of all ischemic strokes. Degenerative microangiopathy and sporadic cerebral amyloid angiography represent the typical acquired cerebral microangiopathies, which are found in over 90 % of cases. Besides, a wide variety of rare, hereditary microangiopathy exists, as e.g. CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), Fabrys disease and MELAS syndrome (Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes). (orig.)

  6. Optical measures of changes in cerebral vascular tone during voluntary breath holding and a Sternberg memory task.

    Science.gov (United States)

    Tan, Chin Hong; Low, Kathy A; Schneider-Garces, Nils; Zimmerman, Benjamin; Fletcher, Mark A; Maclin, Edward L; Chiarelli, Antonio M; Gratton, Gabriele; Fabiani, Monica

    2016-07-01

    The human cerebral vasculature responds to changes in blood pressure and demands for oxygenation via cerebral autoregulation. Changes in cerebrovascular tone (vasoconstriction and vasodilation) also mediate the changes in blood flow measured by the BOLD fMRI signal. This cerebrovascular reactivity is known to vary with age. In two experiments, we demonstrate that cerebral pulse parameters measured using optical imaging can quantify changes in cerebral vascular tone, both globally and locally. In experiment 1, 51 older adults (age range=55-87) performed a voluntary breath-holding task while cerebral pulse amplitude measures were taken. We found significant pulse amplitude variations across breath-holding periods, indicating vasodilation during, and vasoconstriction after breath holding. The breath-holding index (BHI), a measure of cerebrovascular reactivity (CVR) was derived and found to correlate with age. BHI was also correlated with performance in the Modified Mini-Mental Status Examination, even after controlling for age and education. In experiment 2, the same participants performed a Sternberg task, and changes in regional pulse amplitude between high (set-size 6) and low (set-size 2) task loads were compared. Only task-related areas in the fronto-parietal network (FPN) showed significant reduction in pulse amplitude, indicating vasodilation. Non-task-related areas such as the somatosensory and auditory cortices did not show such reductions. Taken together, these experiments suggest that optical pulse parameters can index changes in brain vascular tone both globally and locally, using both physiological and cognitive load manipulations.

  7. Middle cerebral artery blood velocity and plasma catecholamines during exercise

    DEFF Research Database (Denmark)

    Pott, F; Jensen, K; Hansen, H;

    1996-01-01

    During dynamic exercise, mean blood velocity (Vmean) in the middle cerebral artery (MCA) demonstrates a graded increase to work rate and reflects regional cerebral blood flow. At a high work rate, however, vasoactive levels of plasma catecholamines could mediate vasoconstriction of the MCA...

  8. Isolation and Cannulation of Cerebral Parenchymal Arterioles.

    Science.gov (United States)

    Pires, Paulo W; Dabertrand, Fabrice; Earley, Scott

    2016-01-01

    Intracerebral parenchymal arterioles (PAs), which include parenchymal arterioles, penetrating arterioles and pre-capillary arterioles, are high resistance blood vessels branching out from pial arteries and arterioles and diving into the brain parenchyma. Individual PA perfuse a discrete cylindrical territory of the parenchyma and the neurons contained within. These arterioles are a central player in the regulation of cerebral blood flow both globally (cerebrovascular autoregulation) and locally (functional hyperemia). PAs are part of the neurovascular unit, a structure that matches regional blood flow to metabolic activity within the brain and also includes neurons, interneurons, and astrocytes. Perfusion through PAs is directly linked to the activity of neurons in that particular territory and increases in neuronal metabolism lead to an augmentation in local perfusion caused by dilation of the feed PA. Regulation of PAs differs from that of better-characterized pial arteries. Pressure-induced vasoconstriction is greater in PAs and vasodilatory mechanisms vary. In addition, PAs do not receive extrinsic innervation from perivascular nerves - innervation is intrinsic and indirect in nature through contact with astrocytic endfeet. Thus, data regarding contractile regulation accumulated by studies using pial arteries does not directly translate to understanding PA function. Further, it remains undetermined how pathological states, such as hypertension and diabetes, affect PA structure and reactivity. This knowledge gap is in part a consequence of the technical difficulties pertaining to PA isolation and cannulation. In this manuscript we present a protocol for isolation and cannulation of rodent PAs. Further, we show examples of experiments that can be performed with these arterioles, including agonist-induced constriction and myogenic reactivity. Although the focus of this manuscript is on PA cannulation and pressure myography, isolated PAs can also be used for

  9. Application of Wavelet-Based Tools to Study the Dynamics of Biological Processes

    DEFF Research Database (Denmark)

    Pavlov, A. N.; Makarov, V. A.; Mosekilde, Erik;

    2006-01-01

    The article makes use of three different examples (sensory information processing in the rat trigeminal complex, intracellular interaction in snail neurons and multimodal dynamics in nephron autoregulation) to demonstrate how modern approaches to time-series analysis based on the wavelet-transfor...

  10. Measurements of diagnostic examination performance and correlation analysis using microvascular leakage, cerebral blood volume, and blood flow derived from 3T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in glial tumor grading

    International Nuclear Information System (INIS)

    To assess the diagnostic accuracy of microvascular leakage (MVL), cerebral blood volume (CBV) and blood flow (CBF) values derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MR imaging) for grading of cerebral glial tumors, and to estimate the correlation between vascular permeability/perfusion parameters and tumor grades. A prospective study of 79 patients with cerebral glial tumors underwent DSC-MR imaging. Normalized relative CBV (rCBV) and relative CBF (rCBF) from tumoral (rCBVt and rCBFt), peri-enhancing region (rCBVe and rCBFe), and the value in the tumor divided by the value in the peri-enhancing region (rCBVt/e and rCBFt/e), as well as MVL, expressed as the leakage coefficient K2 were calculated. Hemodynamic variables and tumor grades were analyzed statistically and with Pearson correlations. Receiver operating characteristic (ROC) curve analyses were also performed for each of the variables. The differences in rCBVt and the maximum MVL (MVLmax) values were statistically significant among all tumor grades. Correlation analysis using Pearson was as follows: rCBVt and tumor grade, r = 0.774; rCBFt and tumor grade, r = 0.417; MVLmax and tumor grade, r = 0.559; MVLmax and rCBVt, r = 0.440; MVLmax and rCBFt, r = 0.192; and rCBVt and rCBFt, r = 0.605. According to ROC analyses for distinguishing tumor grade, rCBVt showed the largest areas under ROC curve (AUC), except for grade III from IV. Both rCBVt and MVLmax showed good discriminative power in distinguishing all tumor grades. rCBVt correlated strongly with tumor grade; the correlation between MVLmax and tumor grade was moderate. (orig.)

  11. Measurements of diagnostic examination performance and correlation analysis using microvascular leakage, cerebral blood volume, and blood flow derived from 3T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in glial tumor grading

    Energy Technology Data Exchange (ETDEWEB)

    Server, Andres; Nakstad, Per H. [Oslo University Hospital-Ullevaal, Section of Neuroradiology, Department of Radiology and Nuclear Medicine, Oslo (Norway); University of Oslo, Oslo (Norway); Graff, Bjoern A. [Oslo University Hospital-Ullevaal, Department of Radiology and Nuclear Medicine, Oslo (Norway); Orheim, Tone E.D.; Gadmar, Oeystein B. [Oslo University Hospital, Interventional Centre, Oslo (Norway); Schellhorn, Till [Oslo University Hospital-Ullevaal, Section of Neuroradiology, Department of Radiology and Nuclear Medicine, Oslo (Norway); Josefsen, Roger [Oslo University Hospital-Ullevaal, Department of Neurosurgery, Oslo (Norway)

    2011-06-15

    To assess the diagnostic accuracy of microvascular leakage (MVL), cerebral blood volume (CBV) and blood flow (CBF) values derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MR imaging) for grading of cerebral glial tumors, and to estimate the correlation between vascular permeability/perfusion parameters and tumor grades. A prospective study of 79 patients with cerebral glial tumors underwent DSC-MR imaging. Normalized relative CBV (rCBV) and relative CBF (rCBF) from tumoral (rCBVt and rCBFt), peri-enhancing region (rCBVe and rCBFe), and the value in the tumor divided by the value in the peri-enhancing region (rCBVt/e and rCBFt/e), as well as MVL, expressed as the leakage coefficient K{sub 2} were calculated. Hemodynamic variables and tumor grades were analyzed statistically and with Pearson correlations. Receiver operating characteristic (ROC) curve analyses were also performed for each of the variables. The differences in rCBVt and the maximum MVL (MVL{sub max}) values were statistically significant among all tumor grades. Correlation analysis using Pearson was as follows: rCBVt and tumor grade, r = 0.774; rCBFt and tumor grade, r = 0.417; MVL{sub max} and tumor grade, r = 0.559; MVL{sub max} and rCBVt, r = 0.440; MVL{sub max} and rCBFt, r = 0.192; and rCBVt and rCBFt, r = 0.605. According to ROC analyses for distinguishing tumor grade, rCBVt showed the largest areas under ROC curve (AUC), except for grade III from IV. Both rCBVt and MVL{sub max} showed good discriminative power in distinguishing all tumor grades. rCBVt correlated strongly with tumor grade; the correlation between MVL{sub max} and tumor grade was moderate. (orig.)

  12. Cerebral misery perfusion diagnosed using hypercapnic blood-oxygenation-level-dependent contrast functional magnetic resonance imaging: a case report

    Directory of Open Access Journals (Sweden)

    D'Souza Olympio

    2010-02-01

    Full Text Available Abstract Introduction Cerebral misery perfusion represents a failure of cerebral autoregulation. It is an important differential diagnosis in post-stroke patients presenting with collapses in the presence of haemodynamically significant cerebrovascular stenosis. This is particularly the case when cortical or internal watershed infarcts are present. When this condition occurs, further investigation should be done immediately. Case presentation A 50-year-old Caucasian man presented with a stroke secondary to complete occlusion of his left internal carotid artery. He went on to suffer recurrent seizures. Neuroimaging demonstrated numerous new watershed-territory cerebral infarcts. No source of arterial thromboembolism was demonstrable. Hypercapnic blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging was used to measure his cerebrovascular reserve capacity. The findings were suggestive of cerebral misery perfusion. Conclusions Blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging allows the inference of cerebral misery perfusion. This procedure is cheaper and more readily available than positron emission tomography imaging, which is the current gold standard diagnostic test. The most evaluated treatment for cerebral misery perfusion is extracranial-intracranial bypass. Although previous trials of this have been unfavourable, the results of new studies involving extracranial-intracranial bypass in high-risk patients identified during cerebral perfusion imaging are awaited. Cerebral misery perfusion is an important and under-recognized condition in which emerging imaging and treatment modalities present the possibility of practical and evidence-based management in the near future. Physicians should thus be aware of this disorder and of recent developments in diagnostic tests that allow its detection.

  13. Observation of cerebral blood flow dynamic change and prognosis of stroke after large-area cerebral infarction%大面积脑梗死的脑血流动力学动态变化与卒中预后的观察

    Institute of Scientific and Technical Information of China (English)

    温世斌; 夏金花; 彭德强; 尤玉娟; 葛晓玲; 郭百海; 丁志强; 闫贵国

    2013-01-01

    type on the basis of imaging of blood model.In the acute stage of patients with large-area cerebral infarction, bedside transcranial color Doppler(TCD) was used to test the intracranial blood flow dynamic change on the first day and once a week on alternate days and 14 days in the hospital, through the flow velocity of brain artery blood, throb index and blood flow velocity ratio (RVACA and RVPCA) testing, to understand hemodynamic change of intracranial vascular dynamics,to observe hemodynamic changes,and retrospectively analyze with application of the United States National Institutes of Health Stroke Scale (NIHSS) scores and after 3 months survived patients' activities of daily living scale (Barthel index) score, evaluate the relationship between the cerebral blood flow dynamic characteristics and nerve function with the clinic prognosis.Healthy subjects from body check served as controls with gender and age in matches.Results The mean blood flow velocity(Vm) of the brain disease side MCA, mean blood flow velocity with internal carotid artery(ICA) in large-area cerebral infarction were significantly lower than those of control group( P 0.05).Conclusion The patients of large-area cerebral infarction can be evaluated in the vascular occlusion position through the bed TCD dynamic detection, the collateral circulation compensatory and revascularization can be discovered to evaluate the dynamic changes of intracranial pressure and observe the treatment effect of dehydration drop of intracranial pressure.In the completely MCA type patients,if RVACA and RVPCA are higher in the process of treatment,and NIHSS score is stable, these patients are often sensitive to dehydrating agent treatment and medicine conservative treatment can be preferred.

  14. Regulation of regional cerebral blood flow during and between migraine attacks

    DEFF Research Database (Denmark)

    Lauritzen, M; Olsen, T S; Lassen, N A;

    1983-01-01

    in the normally perfused brain. Blood pressure autoregulation was normal in all brain regions. Regional blood flow increase in response to physiological activation was severely impaired in the hypoperfused brain areas, whereas neighboring normally perfused regions reacted normally. Confinement of the regulation......Cerebrovascular reactivity to voluntary hyperventilation, moderate hypertension, and physiological activation was studied in nine patients during induced migraine attacks and in four patients between their attacks. Regional cerebral blood flow was measured by the xenon 133 injection technique...... abnormalities to the area of the oligemia supports our suggestion that the blood flow changes are caused by a change in local metabolism. Between attacks of migraine, the patients had normal regulation of brain circulation....

  15. Dependency of cerebral blood flow upon mean arterial pressure in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten; Larsen, Fin Stolze; Qvist, Jesper;

    2000-01-01

    patients undergoing serial examination after 7 (range, 2-10) days. Six of these patients had an uncomplicated course, one had a protracted recovery, and one died. Autoregulation was not restored in two patients; one died and one had a protracted recovery. CONCLUSION: In patients in the early phase of acute......OBJECTIVE: Patients with acute bacterial meningitis are often treated with sympathomimetics to maintain an adequate mean arterial pressure (MAP). We studied the influence of such therapy on cerebral blood flow (CBF). DESIGN: Prospective physiologic trial. SETTING: The Department of Infectious...... Diseases, Copenhagen University Hospital, Denmark. PATIENTS: Sixteen adult patients with acute bacterial meningitis. INTERVENTION: Infusion of norepinephrine to increase MAP. MEASUREMENTS: During a rise in MAP induced by norepinephrine infusion, we measured relative changes in CBF by transcranial Doppler...

  16. Cerebral angiography in leptomeningitis and cerebritis

    International Nuclear Information System (INIS)

    This is a report of the cerebral angiographic findings in cases of meningitis and cerebritis. Fifty-nine patients, 38 of whom were under 1 year of age, underwent cerebral angiography by means of femoral catheterization. All the patients had signs of increased intracranial pressure, seizures, focal cerebral signs, positive transillumination of the head, and or abnormal brain scan findings. A few patients who did not respond to systemic antibiotics as was expected were also evaluated by means of cerebral angiography. The following characteristic angiographic findings were observed in 18 cases of active meningitis: (1) A hasy appearance around the arteries (halo formation) between the late arterial and capillary phases. (2) Narrowing of the arteries in the basal cistern. This sometimes extended to the peripheral arteries. (3) Irregular caliber following the narrowing of arteries (in few cases). (4) Circulation time so slow that veins could be seen in the late arterial phase. (5) Halo formation around the anterior chroidal artery and the clear appearance of the choroid plexus in the venous phase (when the infectious process reached the choroid plexus). Cerebritis could be identified on the angiograms by two signs: (1) local swelling of the brain (mainly the temporal lobe) and (2) staining around the veins without any abnormal signs in the arterial phase (laminar staining). In conclusion, angiography is a meaningful test by which to determine the phase of meningitis and cerebritis. These two conditions should be treated based on valid information obtained by means of CSF examinations and neuroradiological tests, especially CT scan and cerebral angiography. (author)

  17. Análisis de Sensibilidad en Simulaciones Fluido Dinámicas de Aneurismas Cerebrales Incluyendo Interacción Fluido Estructura Sensibility Analysis in Computational Fluid Dynamics of Cerebral Aneurysm including Fluid Structure Interaction

    Directory of Open Access Journals (Sweden)

    Alvaro Valencia

    2010-01-01

    Full Text Available Se presenta un estudio sobre sensibilidad de los resultados de simulación fluido dinámica (CFD en modelos de aneurismas cerebrales, incluyendo la interacción entre la pared arterial y el fluido (FSI. Con 83 modelos reconstruidos de aneurismas cerebrales se hizo un estudio geométrico y se seleccionó un caso para estudiar la fluido dinámica en detalle. Se varió el número de sifones carotideos usados para la simulación CFD. Se realizaron cinco simulaciones FSI variando el modulo de elasticidad arterial y el espesor arterial, y se reportó el efecto de la hipertensión arterial en los resultados. Las simulaciones FSI mostraron que el efecto más relevante en el incremento del estado de esfuerzos en la aneurisma es la hipertensión arterial, con esfuerzos máximos cercanos a 900 kPa. Se concluye que las simulaciones FSI se deben usar para determinar simultáneamente el estado de esfuerzos de la pared y la fluido dinámica dentro de aneurismas.A sensitivity study of the results provided by computational fluid dynamics (CFD in models of cerebral aneurysms including fluid structure interaction (FSI was performed. With 83 reconstructed models of cerebral aneurysms, a geometrical study was done and one case was selected for a detailed study of the computational fluid dynamics. In this model the number of carotid siphon used for the CFD simulations was varied. In the FSI study, five simulations were conducted varying the elastic modulus of the artery and the arterial wall thickness, and the effect of hypertension on the results was reported. The FSI simulations have shown that the most important parameter that affeets the aneurysm wall stress state is the arterial hypertension with máximum stress of around 900 kPa. It is concluded that FSI simulations must be used to simultaneously determine the wall stress and the fluid dynamics inside cerebral aneurysm.

  18. Autoregulation of the Drosophila Noncoding roX1 RNA Gene.

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    Chiat Koo Lim

    Full Text Available Most genes along the male single X chromosome in Drosophila are hypertranscribed about two-fold relative to each of the two female X chromosomes. This is accomplished by the MSL (male-specific lethal complex that acetylates histone H4 at lysine 16. The MSL complex contains two large noncoding RNAs, roX1 (RNA on X and roX2, that help target chromatin modifying enzymes to the X. The roX RNAs are functionally redundant but differ in size, sequence, and transcriptional control. We wanted to find out how roX1 production is regulated. Ectopic DC can be induced in wild-type (roX1(+ roX2(+ females if we provide a heterologous source of MSL2. However, in the absence of roX2, we found that roX1 expression failed to come on reliably. Using an in situ hybridization probe that is specific only to endogenous roX1, we found that expression was restored if we introduced either roX2 or a truncated but functional version of roX1. This shows that pre-existing roX RNA is required to positively autoregulate roX1 expression. We also observed massive cis spreading of the MSL complex from the site of roX1 transcription at its endogenous location on the X chromosome. We propose that retention of newly assembled MSL complex around the roX gene is needed to drive sustained transcription and that spreading into flanking chromatin contributes to the X chromosome targeting specificity. Finally, we found that the gene encoding the key male-limited protein subunit, msl2, is transcribed predominantly during DNA replication. This suggests that new MSL complex is made as the chromatin template doubles. We offer a model describing how the production of roX1 and msl2, two key components of the MSL complex, are coordinated to meet the dosage compensation demands of the male cell.

  19. Investigations of the regulation of cerebral circulation by means of functional changes observed on unanaesthetized rabbits during hypoxia, paradoxical sleep and after whole-body γ-exposure (850-150 rad dose range)

    International Nuclear Information System (INIS)

    Both the general effects and the effects on cerebral circulation of whole-body exposure were studied at doses of 850, 650, 450, 250 and 150 rads. Early functional changes following exposure demonstrated two juxtaposed mechanisms, a central one and a peripheral one. The central process, slightly sensitive to the dose-effect, occurred earlier and should be at the origin of hyperthermia, hyperventilation, tachycardia, skin vasoconstruction and a slight increase of arterial pressure. The peripheral mechanisms, occurring slightly later should be more sensitive to the dose-effect and might be at the origin of hypothermic effects and cardiovascular depression. The increase of cerebral blood flow occurring at the 450 rad dose should be best explained by the presence of vasotropic substances. A twofold component of cerebral vasotonicity should be assumed that would depend on the autonomous nervous system and myogenous autoregulation

  20. Magnetic Resonance Imaging Quantification of Regional Cerebral Blood Flow and Cerebrovascular Reactivity to Carbon Dioxide in Normotensive and Hypertensive Rats

    Science.gov (United States)

    Leoni, Renata F.; Paiva, Fernando F.; Henning, Erica C.; Nascimento, George C.; Tannús, Alberto; de Araujo, Draulio B.; Silva, Afonso C.

    2011-01-01

    Hypertension afflicts 25% of the general population and over 50% of the elderly. In the present work, arterial spin labeling MRI was used to non-invasively quantify regional cerebral blood flow (CBF), cerebrovascular resistance and CO2 reactivity in spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY), at two different ages (3 months and 10 months) and under the effects of two anesthetics, α-chloralose and 2% isoflurane (1.5 MAC). Repeated CBF measurements were highly consistent, differing by less than 10% and 18% within and across animals, respectively. Under α-chloralose, whole brain CBF at normocapnia did not differ between groups (young WKY: 61±3ml/100g/min; adult WKY: 62±4ml/100g/min; young SHR: 70±9ml/100g/min; adult SHR: 69±8ml/100g/min), indicating normal cerebral autoregulation in SHR. At hypercapnia, CBF values increased significantly, and a linear relationship between CBF and PaCO2 levels was observed. In contrast, 2% isoflurane impaired cerebral autoregulation. Whole brain CBF in SHR was significantly higher than in WKY rats at normocapnia (young SHR: 139±25ml/100g/min; adult SHR: 104±23ml/100g/min; young WKY: 55±9ml/100g/min; adult WKY: 71±19ml/100g/min). CBF values increased significantly with increasing CO2; however, there was a clear saturation of CBF at PaCO2 levels greater than 70 mmHg in both young and adult rats, regardless of absolute CBF values, suggesting that isoflurane interferes with the vasodilatory mechanisms of CO2. This behavior was observed for both cortical and subcortical structures. Under either anesthetic, CO2 reactivity values in adult SHR were decreased, confirming that hypertension, when combined with age, increases cerebrovascular resistance and reduces cerebrovascular compliance. PMID:21708273

  1. Cerebral blood flow tomography with xenon-133

    DEFF Research Database (Denmark)

    Lassen, N A

    1985-01-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-133. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission...

  2. Cerebral Palsy (CP) Quiz

    Science.gov (United States)

    ... Submit Button Past Emails CDC Features Pop Quiz: Cerebral Palsy Language: English Español (Spanish) Recommend on Facebook Tweet ... Sandy is the parent of a child with cerebral palsy and the Board President of Gio’s Garden , a ...

  3. The Effects of Acupuncture on Cerebral and Muscular Microcirculation: A Systematic Review of Near-Infrared Spectroscopy Studies

    Directory of Open Access Journals (Sweden)

    Ming-Yu Lo

    2015-01-01

    Full Text Available Acupuncture produces physiological effects via stimulating acupoints, proximal or distal to the region of effect. Near-infrared spectroscopy (NIRS noninvasively measures tissue-level hemodynamics in real time. We review the literature investigating the effect of acupuncture on muscular and/or cerebral microcirculation. As the basis, we queried PubMed in June 2014 for articles mentioning both acupuncture and NIRS in title/abstract. The reviewed papers investigated either cerebral (n = 11 or muscular hemodynamics (n = 5 and, based on STRICTA for reporting acupuncture methodology, were overall poor in quality. Acupuncture was found to influence regional oxygen saturation in cerebral and muscular tissue. The cortical response in healthy subjects varied across studies. For subjects with stroke or cerebrovascular dementia, findings suggest that acupuncture may modulate dysfunction in cerebral autoregulation. The muscular response to pressure techniques was more intense than that to needling or laser. Probe proximity could impact measurement sensitivity. No one study simultaneously investigated the direct and remote responses. Research utilizing NIRS to investigate the hemodynamics of acupuncture presently lacks in scope and quality. Improved designs, for example, placebo-controlled, randomized trials, and standardized intervention reporting will raise study quality. Exploiting NIRS in clinical settings, such as stroke, migraine, or other pain conditions, is worthwhile.

  4. Non-ionizing radiofrequency electromagnetic waves traversing the head can be used to detect cerebrovascular autoregulation responses

    Science.gov (United States)

    Oziel, M.; Hjouj, M.; Gonzalez, C. A.; Lavee, J.; Rubinsky, B.

    2016-02-01

    Monitoring changes in non-ionizing radiofrequency electromagnetic waves as they traverse the brain can detect the effects of stimuli employed in cerebrovascular autoregulation (CVA) tests on the brain, without contact and in real time. CVA is a physiological phenomenon of importance to health, used for diagnosis of a number of diseases of the brain with a vascular component. The technology described here is being developed for use in diagnosis of injuries and diseases of the brain in rural and economically underdeveloped parts of the world. A group of nine subjects participated in this pilot clinical evaluation of the technology. Substantial research remains to be done on correlating the measurements with physiology and anatomy.

  5. CRP-dependent positive autoregulation and proteolytic degradation regulate competence activator Sxy of Escherichia coli

    DEFF Research Database (Denmark)

    Jaskólska, Milena; Gerdes, Kenn

    2015-01-01

    that Sxy is an unstable protein and that its cellular level is negatively regulated at the post-translational level via degradation by Lon protease. Interestingly, in the Gram-positive model organism Bacillus subtilis, the competence master regulator ComK is also positively autoregulated at the level......Natural competence, the ability of bacteria to take up exogenous DNA and incorporate it into their chromosomes, is in most bacteria a transient phenomenon under complex genetic and environmental control. In the Gram-negative bacteria Haemophilus influenzae and Vibrio cholerae, the master regulator...... of transcription and negatively regulated by proteolysis. Together, these findings reveal striking similarities between the competence regulons of a Gram-positive and a Gram-negative bacterium....

  6. Mapping of cerebral metabolic rate of oxygen using dynamic susceptibility contrast and blood oxygen level dependent MR imaging in acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Gersing, Alexandra S.; Schwaiger, Benedikt J. [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); University of California, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Ankenbrank, Monika; Toth, Vivien; Bauer, Jan S.; Zimmer, Claus [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Janssen, Insa [Technical University Munich, Department of Neurosurgery, Munich (Germany); Kooijman, Hendrik [Philips Healthcare, Hamburg (Germany); Wunderlich, Silke [Technical University Munich, Department of Neurology, Munich (Germany); Preibisch, Christine [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Technical University Munich, Department of Neurology, Munich (Germany)

    2015-12-15

    MR-derived cerebral metabolic rate of oxygen utilization (CMRO{sub 2}) has been suggested to be analogous to PET-derived CMRO{sub 2} and therefore may be used for detection of viable tissue at risk for infarction. The purpose of this study was to evaluate MR-derived CMRO{sub 2} mapping in acute ischemic stroke in relation to established diffusion- and perfusion-weighted imaging. In 23 patients (mean age 63 ± 18.7 years, 11 women) with imaging findings for acute ischemic stroke, relative oxygen extraction fraction was calculated from quantitative transverse relaxation times (T2, T2*) and relative cerebral blood volume using a quantitative blood oxygenation level dependent (BOLD) approach in order to detect a local increase of deoxyhemoglobin. Relative CMRO{sub 2} (rCMRO{sub 2}) maps were calculated by multiplying relative oxygen extraction fraction (rOEF) by cerebral blood flow, derived from PWI. After co-registration, rCMRO{sub 2} maps were evaluated in comparison with apparent diffusion coefficient (ADC) and time-to-peak (TTP) maps. Mean rCMRO{sub 2} values in areas with diffusion-restriction or TTP/ADC mismatch were compared with rCMRO{sub 2} values in the contralateral tissue. In tissue with diffusion restriction, mean rCMRO{sub 2} values were significantly decreased compared to perfusion-impaired (17.9 [95 % confidence interval 10.3, 25.0] vs. 58.1 [95 % confidence interval 50.1, 70.3]; P < 0.001) and tissue in the contralateral hemisphere (68.2 [95 % confidence interval 61.4, 75.0]; P < 0.001). rCMRO{sub 2} in perfusion-impaired tissue showed no significant change compared to tissue in the contralateral hemisphere (58.1 [95 % confidence interval 50.1, 70.3] vs. 66.7 [95 % confidence interval 53.4, 73.4]; P = 0.34). MR-derived CMRO{sub 2} was decreased within diffusion-restricted tissue and stable within perfusion-impaired tissue, suggesting that this technique may be adequate to reveal different pathophysiological stages in acute stroke. (orig.)

  7. Temporal dynamics of cerebral blood flow, cortical damage, apoptosis, astrocyte-vasculature interaction and astrogliosis in the pericontusional region after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Sonia eVillapol

    2014-06-01

    Full Text Available Traumatic brain injury (TBI results in a loss of brain tissue at the moment of impact in the cerebral cortex. Subsequent secondary injury involves the release of molecular signals with dramatic consequences for the integrity of damaged tissue, leading to the evolution of a pericontusional-damaged area minutes to days after in the initial injury. The mechanisms behind the progression of tissue loss remain under investigation. In this study, we analyzed the spatial-temporal profile of blood flow, apoptotic and astrocytic-vascular events in the cortical regions around the impact site at time points ranging from 5 hours to 2 months after TBI. We performed a mild-moderate controlled cortical impact injury in young adult mice and analyzed the glial and vascular response to injury. We observed a dramatic decrease in perilesional cerebral blood flow (CBF immediately following the cortical impact that lasted until days later. CBF finally returned to baseline levels by 30 days post-injury (dpi. The initial impact also resulted in an immediate loss of tissue and cavity formation that gradually increased in size until 3 dpi. An increase in dying cells localized in the pericontusional region and a robust astrogliosis were also observed at 3 dpi. A strong vasculature interaction with astrocytes was established at 7 dpi. Glial scar formation began at 7 dpi and seemed to be compact by 60 dpi. Altogether, these results suggest that TBI results in a progression from acute neurodegeneration that precedes astrocytic activation, reformation of the neurovascular unit to glial scar formation. Understanding the multiple processes occurring after TBI is critical to the ability to develop neuroprotective therapeutics to ameliorate the short and long-term consequences of brain injury.

  8. Unilateral cerebral polymicrogyria with ipsilateral cerebral hemiatrophy

    International Nuclear Information System (INIS)

    We evaluated six children in whom MR imaging showed unilateral cerebral polymicrogyria associated with ipsilateral cerebral atrophy and ipsilateral brain stem atrophy. The aim of this study was to clarify whether this disorder based on neuroimaging constitutes a new homogeneous clinical entity. The subjects were six children whose ages at the time of MR imaging ranged from 8 months to 11 years. Their clinical and MR features were analyzed. All of the children were born between 38 and 42 weeks gestation, without any significant perinatal events. Spastic hemiplegia and epilepsy were observed in all of the patients, and mental retardation was observed in four. The MR findings included unilateral cerebral polymicrogyria associated with ipsilateral cerebral hemiatrophy and ipsilateral brain stem atrophy in all patients. The ipsilateral sylvian fissure was hypoplastic in four patients. These patients showed relatively homogeneous clinical and neuroimaging features. Although the additional clinical features varied according to the site and the extent affected by the polymicrogyria, this disorder could constitute a new relatively homogeneous clinical entity. (orig.)

  9. Unilateral cerebral polymicrogyria with ipsilateral cerebral hemiatrophy

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Katsumi [Department of Radiology, Kyoto City Hospital, 1-2 Higashi-Takada-cho, Mibu, Nakagyo-ku, 604-8845 Kyoto (Japan); Kanda, Toyoko; Yamori, Yuriko [Department of Pediatric Neurology, St. Joseph Hospital for Handicapped Children, 603-8323 Kyoto (Japan)

    2002-10-01

    We evaluated six children in whom MR imaging showed unilateral cerebral polymicrogyria associated with ipsilateral cerebral atrophy and ipsilateral brain stem atrophy. The aim of this study was to clarify whether this disorder based on neuroimaging constitutes a new homogeneous clinical entity. The subjects were six children whose ages at the time of MR imaging ranged from 8 months to 11 years. Their clinical and MR features were analyzed. All of the children were born between 38 and 42 weeks gestation, without any significant perinatal events. Spastic hemiplegia and epilepsy were observed in all of the patients, and mental retardation was observed in four. The MR findings included unilateral cerebral polymicrogyria associated with ipsilateral cerebral hemiatrophy and ipsilateral brain stem atrophy in all patients. The ipsilateral sylvian fissure was hypoplastic in four patients. These patients showed relatively homogeneous clinical and neuroimaging features. Although the additional clinical features varied according to the site and the extent affected by the polymicrogyria, this disorder could constitute a new relatively homogeneous clinical entity. (orig.)

  10. Improved detectability of microcirculatory dynamics by laser speckle flowmetry

    DEFF Research Database (Denmark)

    Postnov, Dmitry D; Sosnovtseva, Olga; Tuchin, Valery V

    2015-01-01

    Mechanisms of renal autoregulation generate oscillations in arterial blood flow at several characteristic frequencies. Full-field laser speckle flowmetry provides a real-time imaging of superficial blood microcirculation. The possibility to detect changes in oscillatory dynamics is an important...... issue in biomedical applications. In this paper we show how laser power density affects quality of the recorded signal and improves detectability of temporal changes in microvascular perfusion....

  11. Cerebral Aneurysms Fact Sheet

    Science.gov (United States)

    ... cerebral aneurysm from forming. People with a diagnosed brain aneurysm should carefully control high blood pressure, stop smoking, and avoid cocaine use or other stimulant drugs. They should also ...

  12. Cerebral amyloid angiopathy

    Science.gov (United States)

    ... Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice . 6th ed. Philadelphia, PA: Elsevier ... al. Course of cerebral amyloid angiopathy-related inflammation. Neurology. 2007;68:1411-1416. PMID: 17452586 www.ncbi. ...

  13. Cerebral Palsy Litigation

    OpenAIRE

    Sartwelle, Thomas P.; Johnston, James C.

    2015-01-01

    The cardinal driver of cerebral palsy litigation is electronic fetal monitoring, which has continued unabated for 40 years. Electronic fetal monitoring, however, is based on 19th-century childbirth myths, a virtually nonexistent scientific foundation, and has a false positive rate exceeding 99%. It has not affected the incidence of cerebral palsy. Electronic fetal monitoring has, however, increased the cesarian section rate, with the expected increase in mortality and morbidity risks to mothe...

  14. Rehabilitation in cerebral palsy.

    OpenAIRE

    Molnar, G. E.

    1991-01-01

    Cerebral palsy is the most frequent physical disability of childhood onset. Over the past four decades, prevalence has remained remarkably constant at 2 to 3 per 1,000 live births in industrialized countries. In this article I concentrate on the rehabilitation and outcome of patients with cerebral palsy. The epidemiologic, pathogenetic, and diagnostic aspects are highlighted briefly as they pertain to the planning and implementation of the rehabilitation process.

  15. Cerebral palsy and congenital malformations

    DEFF Research Database (Denmark)

    Garne, Ester; Dolk, Helen; Krägeloh-Mann, Inge;

    2007-01-01

    AIM: To determine the proportion of children with cerebral palsy (CP) who have cerebral and non-cerebral congenital malformations. METHODS: Data from 11 CP registries contributing to the European Cerebral Palsy Database (SCPE), for children born in the period 1976-1996. The malformations were...... classified as recognized syndromes, chromosomal anomalies, cerebral malformations or non-cerebral malformations. Prevalence of malformations was compared to published data on livebirths from a European database of congenital malformations (EUROCAT). RESULTS: Overall 547 out of 4584 children (11.9%) with CP...... were reported to have a congenital malformation. The majority (8.6% of all children) were diagnosed with a cerebral malformation. The most frequent types of cerebral malformations were microcephaly and hydrocephaly. Non-cerebral malformations were present in 97 CP children and in further 14 CP children...

  16. Analysis of nonstationarity in renal autoregulation mechanisms using time-varying transfer and coherence functions

    DEFF Research Database (Denmark)

    Chon, Ki H; Zhong, Yuru; Moore, Leon C;

    2008-01-01

    The extent to which renal blood flow dynamics vary in time and whether such variation contributes substantively to dynamic complexity have emerged as important questions. Data from Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR) were analyzed by time-varying transfer functions...

  17. Mechanisms underlying phase lag between systemic arterial blood pressure and cerebral blood flow velocity.

    Science.gov (United States)

    Kuo, Terry B J; Chern, Chang-Ming; Yang, Cheryl C H; Hsu, Hung-Yi; Wong, Wen-Jang; Sheng, Wen-Yung; Hu, Han-Hwa

    2003-01-01

    To explore the mechanisms underlying the phase lag between oscillations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV), ABP and CBFV signals were recorded noninvasively from normal volunteers who lay quietly in a supine position. Mean ABP (MAP) and CBFV (MFV) were calculated beat-to-beat by means of integration. Cerebral vascular resistance (CVR) was calculated by dividing MAP with MFV. Frequency domain analysis of MAP, MFV and CVR signals revealed very-low frequency (VLF, 0.016-0.04 Hz), low-frequency (LF, 0.04-0.15 Hz), and high-frequency (HF, 0.15-0.4 Hz) components. The transfer phase of MAP-CVR coupling in the LF and HF range was frequency-dependent, which is equivalent to a time delay of 2 s. However, the transfer phase differed in the CVR-MFV coupling in that the phase was distributed around 180 degrees across the LF and HF ranges. Cross-correlation analysis revealed a positive relationship between MAP-CVR coupling, with MAP leading by 2 s, and a negative relationship between CVR-MFV coupling, with CVR leading by 0.3 s. We concluded that the phase lag between oscillations in ABP and CBFV was chiefly contributed to by the starting latency of cerebral autoregulation (i.e. cerebral vasomotion, revealed by MAP-CVR coupling). Moreover, the negative correlation of the CVR-MFV coupling could offer a different explanation for the physiologic significance of the phase lead of CBFV-ABP oscillations.

  18. Challenges in understanding the impact of blood pressure management on cerebral oxygenation in the preterm brain

    Directory of Open Access Journals (Sweden)

    Aminath eAzhan

    2012-12-01

    Full Text Available Systemic hypotension in preterm infants has been related to increased mortality, cerebrovascular lesions and neurodevelopmental morbidity. Treatment of hypotension with inotropic medications aims at preservation of end organ perfusion and oxygen delivery, especially the brain. The common inotropic medications in preterm infants include dopamine, dobutamine, adrenalin, with adjunctive use of corticosteroids in cases of refractory hypotension. Whether maintenance of mean arterial blood pressure (MAP by use of inotropic medication is neuroprotective or not remains unclear. This review explores the different inotropic agents and their effects on perfusion and oxygenation in the preterm brain, in clinical studies as well as in animal models. Dopamine and adrenalin, because of their -adrenergic vasoconstrictor actions, have raised concerns of reduction in cerebral blood flow (CBF. Several studies in hypotensive preterm infants have shown that dopamine elevates CBF together with increased MAP, in keeping with limited cerebro-autoregulation. Adrenaline is also effective in raising cerebral perfusion together with MAP in preterm infants. Experimental studies in immature animals show no cerebro-vasoconstrictive effects of dopamine or adrenaline, but demonstrate the consistent findings of increased cerebral perfusion and oxygenation with the use of dopamine, dobutamine and adrenaline, alongside with raised MAP. Both clinical and animal studies report the transitory effects of adrenaline in increasing plasma lactate, and blood glucose, which might render its use as a 2nd line therapy. To investigate the cerebral effects of inotropic agents in long-term outcome in hypotensive preterm infants, carefully designed prospective research possibly including preterm infants with permissive hypotension is required. Preterm animal models would be useful in investigating the relationship between the physiological effects of inotropes and histopathology outcomes in

  19. BIOMECHANICAL PRINCIPLES PHYSICAL REHABILITATION OF CHILDREN WITH CEREBRAL PALSY

    OpenAIRE

    S. D. Korshunov; K. V. Davletyarova; L. V. Kapilevich

    2016-01-01

    Aim. We studied the basic biomechanical principles of physical rehabilitation of children with cerebral palsy.Materials and methods. Methods of Motion Tracking and electromyography investigated the biomechanical characteristics of gait in children with cerebral palsy. It is shown that the main differences between dynamic stereotype walk pediatric patients is to delay moving forward center of gravity and the disorganization of the lower limb movements (especially knee) in the vertical plane. P...

  20. Nanomedicine in cerebral palsy

    Directory of Open Access Journals (Sweden)

    Balakrishnan B

    2013-11-01

    Full Text Available Bindu Balakrishnan,1 Elizabeth Nance,1 Michael V Johnston,2 Rangaramanujam Kannan,3 Sujatha Kannan1 1Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University; Baltimore, MD, USA; 2Department of Neurology and Pediatrics, Kennedy Krieger Institute, Baltimore, MD, USA; 3Department of Ophthalmology, Center for Nanomedicine, Johns Hopkins University, Baltimore, MD, USA Abstract: Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the developing brain that occurs either in utero or soon after birth can result in the motor, sensory, and cognitive deficits seen in cerebral palsy. Although the etiologies for cerebral palsy are variable, neuroinflammation plays a key role in the pathophysiology of the brain injury irrespective of the etiology. Currently, there is no effective cure for cerebral palsy. Nanomedicine offers a new frontier in the development of therapies for prevention and treatment of brain injury resulting in cerebral palsy. Nanomaterials such as dendrimers provide opportunities for the targeted delivery of multiple drugs that can mitigate several pathways involved in injury and can be delivered specifically to the cells that are responsible for neuroinflammation and injury. These materials also offer the opportunity to deliver agents that would promote repair and regeneration in the brain, resulting not only in attenuation of injury, but also enabling normal growth. In this review, the current advances in nanotechnology for treatment of brain injury are discussed with specific relevance to cerebral palsy. Future directions that would facilitate clinical translation in neonates and children are also addressed. Keywords: dendrimer, cerebral palsy, neuroinflammation, nanoparticle, neonatal brain injury, G4OH-PAMAM

  1. La parálisis cerebral como una condición dinámica del cerebro: un estudio secuencial del desarrollo de niños hasta los 6 años de edad / Cerebral Palsy as a Dynamic Condition of the Brain: A Sequential Study of the Development of Children up to 6 Years of Age

    OpenAIRE

    Enrique Moraleda Barreno; Modesto Jesús Romero López; María José Cayetano Menéndez

    2013-01-01

    La parálisis cerebral es un trastorno motor debido a inmadurez cerebral con numerosos déficits asociados, incluidos los adaptativos, sociales, motores, cognitivos y de la comunicación, y con gran impacto en el desarrollo. El objetivo del presente estudio fue estudiar el desarrollo durante un año de niños con parálisis cerebral de uno a seis años. El método empleado fue un diseño ex post facto evolutivo secuencial. Se utilizó la prueba de screening del Inventario de Desarrollo de Battelle en u...

  2. Regulation of voltage-gated sodium channel expression in cancer: hormones, growth factors and auto-regulation.

    Science.gov (United States)

    Fraser, Scott P; Ozerlat-Gunduz, Iley; Brackenbury, William J; Fitzgerald, Elizabeth M; Campbell, Thomas M; Coombes, R Charles; Djamgoz, Mustafa B A

    2014-03-19

    Although ion channels are increasingly being discovered in cancer cells in vitro and in vivo, and shown to contribute to different aspects and stages of the cancer process, much less is known about the mechanisms controlling their expression. Here, we focus on voltage-gated Na(+) channels (VGSCs) which are upregulated in many types of carcinomas where their activity potentiates cell behaviours integral to the metastatic cascade. Regulation of VGSCs occurs at a hierarchy of levels from transcription to post-translation. Importantly, mainstream cancer mechanisms, especially hormones and growth factors, play a significant role in the regulation. On the whole, in major hormone-sensitive cancers, such as breast and prostate cancer, there is a negative association between genomic steroid hormone sensitivity and functional VGSC expression. Activity-dependent regulation by positive feedback has been demonstrated in strongly metastatic cells whereby the VGSC is self-sustaining, with its activity promoting further functional channel expression. Such auto-regulation is unlike normal cells in which activity-dependent regulation occurs mostly via negative feedback. Throughout, we highlight the possible clinical implications of functional VGSC expression and regulation in cancer. PMID:24493753

  3. Cerebral abscess in children

    International Nuclear Information System (INIS)

    A cerebral abscess (CA) is a focal, infectious process only or multiple, located in the cerebral parenchyma that produces tisular lysis and it behaves like a lesion of space occupative, being a suppurative illness, who origin is a distant infection, or for continuity that studies initially as an area of focal cerebritis and it is developed to a collection surrounded purulent. At the moment they are perfecting technical and protocols diagnoses and therapeutic and measures for allow to control the natural history of the illness, making from the confrontation to this pathology a necessarily interdisciplinary complicated art, stiller in the infantile population, due to their difficulty in the diagnosis and the relevance of the same one. The paper includes epidemiology, etiology, risk factors, localization, pathology, clinic, diagnoses, treatment and diagnostic images

  4. Cerebral hemodynamics in migraine

    DEFF Research Database (Denmark)

    Hachinski, V C; Olesen, Jes; Norris, J W;

    1977-01-01

    Clinical and angiographic findings in migraine are briefly reviewed in relation to cerebral hemodynamic changes shown by regional cerebral blood flow (rCBF) studies. Three cases of migraine studied by the intracarotid xenon 133 method during attacks are reported. In classic migraine, with typical...... prodromal symptoms, a decrease in cerebral blood flow has been demonstrated during the aura. Occasionally, this flow decrease persists during the headache phase. In common migraine, where such prodromata are not seen, a flow decrease has not been demonstrated. During the headache phase of both types...... of migraine, rCBF has usually been found to be normal or in the high range of normal values. The high values may represent postischemic hyperemia, but are probably more frequently secondary to arousal caused by pain. Thus, during the headache phase rCBF may be subnormal, normal or high. These findings do...

  5. Cerebral fat embolism

    International Nuclear Information System (INIS)

    A case of cerebral fat embolism is reported. A 18-year-old patient with multiple bone fractures was in semiconma immediately after an injury. Brain CT showed no brain swelling or intracranial hematoma. Hypoxemia and alcoholemia were noted on admission, which returned to normal without improvement of consciousness level. In addition, respiratory symptoms with positive radiographic changes, tachycardia, pyrexia, sudden drop in hemoglobin level, and sudden thrombocytopenia developed. These symptoms were compatible with Gurd's criteria of systemic fat embolism. Eight days after injury, multiple low density areas appeared on CT and disappeared within the subsequent two weeks, and subdural effusion with cerebral atrophy developed. These CT findings were not considered due to cerebral trauma. Diagnosis of cerebral fat embolism was made. The subdural effusion was drained. Neurologic and pulmonary recoveries took place slowly and one month following the injury the patient became alert and exhibited fully coordinated limb movement. The CT scans of the present case well corresponded with hitherto reported pathological findings. Petechiae in the white matter must have developed on the day of injury, which could not be detected by CT examination. It is suggested that some petechial regions fused to purpuras and then gradually resolved when they were detected as multiple low density areas on CT. CT in the purpuras phase would have shown these lesions as high density areas. These lesions must have healed with formation of tiny scars and blood pigment which were demonstrated as the disappearance of multiple low density areas by CT examination. Cerebral atrophy and subsequent subdural effusion developed as a result of demyelination. The patient took the typical clinical course of cerebral fat embolism and serial CT scans served for its assessment. (author)

  6. Experimental Focal Cerebral Ischemia

    DEFF Research Database (Denmark)

    Christensen, Thomas

    2007-01-01

    Focal cerebral ischemia due to occlusion of a major cerebral artery is the cause of ischemic stroke which is a major reason of mortality, morbidity and disability in the populations of the developed countries. In the seven studies summarized in the thesis focal ischemia in rats induced by occlusion......-PBN on the periinfarct depolarizations and infarct volume was investigated. In study number six, the activity of the mitochondrial electron transport complexes I, II and IV was evaluated histochemically during reperfusion after MCAO in order to assess the possible role of mitochondrial dysfunction in focal ischemic...

  7. 咀嚼对脑血流动力学影响的临床实验研究%Clinical experimental study on the effects of mastication on the dynamics of cerebral blood flow

    Institute of Scientific and Technical Information of China (English)

    魏洁; 陈树国; 徐璟; 郭长军; 袁硕

    2011-01-01

    目的 观察正常(铪)受试者咀嚼运动前后脑血流的改变,探讨咀嚼对脑血流动力学的影响及意义.方法 应用经颅彩色多谱勒超声扫描仪(transcranial color doppler,TCCD),探测30名正常(胎)受试者在安静状态下和咀嚼无糖口香糖10分钟后脑血流速的改变,对大脑中动脉收缩期峰流速(systolic peak flow velocity,Vs)、舒张期末峰流速(enddiastolic peak flow velocity,Vd)、平均峰流速(mean peak flow velocity,Vm)进行统计分析.结果 ①30名受试者咀嚼前脑血流速值均数(单位:cm/s):收缩期峰流速(Vs)-91.785,舒张期末峰流速(Vd)-39.385,平均峰流速(Vm)-55.735;咀嚼后均数:收缩期峰流速(Vs)-103.030,舒张期末峰流速(Vd)-46.015,平均峰流速(Vm)-64.090;②经两样本均数f检验可知咀嚼前后的大脑中动脉的收缩期峰流速(Vs)、舒张期末峰流速(Vd)、平均峰流速(Vm)的结果在男性与女性之间均无显著性差异(P>0.05);③受试者咀嚼前后配对t检验结果显示,受试者咀嚼后大脑中动脉收缩期峰流速(Vs)、舒张期末峰流速(Vd)及平均峰流速(Vm)与咀嚼前相比均有显著性差异(P<o.05).结论 咀嚼可使大脑中动脉血管充盈度增加,血流速度显著加快.%Objective To observe the cerebral blood flow changes of normal occlusion subjects before and after the movement of chewing, and to investigate the effects and significance of chewing on cerebral blood flow dynamics. Methods Transcranial Color Doppler (TCCD) was used to detect the changes of cerebral blood flow in 30 normal occlusion subjects in a quiet state and 10 minutes after chewing sugarless gum, and the systolic peak flow velocity (Vs), enddiastolic peak flow velocity (Vd), mean peak flow velocity (Vm) were all statistically analyzed. Results (Dthe mean value of cerebral blood flow of 30 subjects before chewing (unit: cm/s): systolic peak flow velocity (Vs) -91.785, enddiastolic peak flow velocity (Vd) -39.385, and

  8. Cerebral atrophic and degenerative changes following various cerebral diseases, (1)

    International Nuclear Information System (INIS)

    Patients having cerebral atrophic and degenerative changes following hypoglycemia, cerebral contusion, or cerebral hypoxia including cerebrovascular disorders were reported. Description was made as to cerebral changes visualized on CT images and clinical courses of a patient who revived 10 minutes after heart stoppage during neurosurgery, a newborn with asphyxia, a patient with hypoglycemia, a patient who suffered from asphyxia by an accident 10 years before, a patient with carbon monoxide poisoning at an acute stage, a patient who had carbon monoxide poisoning 10 years before, a patient with diffuse cerebral ischemic changes, a patient with cerebral edema around metastatic tumor, a patient with respiration brain, a patient with neurological sequelae after cerebral contusion, a patient who had an operation to excise right parietal lobe artery malformation, and a patient who was shooted by a machine gun and had a lead in the brain for 34 years. (Tsunoda, M.)

  9. Evaluation of postural stability in children with hemiplegic cerebral palsy

    Science.gov (United States)

    Kenis-Coskun, Ozge; Giray, Esra; Eren, Beyhan; Ozkok, Ozlem; Karadag-Saygi, Evrim

    2016-01-01

    [Purpose] Postural stability is the ability of to maintain the position of the body within the support area. This function is affected in cerebral palsy. The aim of the present study was to compare static and dynamic postural stability between children with hemiplegic cerebral palsy and healthy controls. [Subjects and Methods] Thirty-seven children between the ages of 5 and 14 diagnosed with hemiplegic cerebral palsy (19 right, 18 left) and 23 healthy gender- and age-matched controls were included in the study. Postural stability was evaluated in both of the groups using a Neurocom Balance. Sway velocity was measured both with the eyes open and closed. Sit to stand and turning abilities were also assessed. [Results] The sway velocities with the eyes open and closed were significantly different between the groups. The weight transfer time in the Sit to Stand test was also significantly slower in children with cerebral palsy. Children with cerebral palsy also showed slower turning times and greater sway velocities during the Step and Quick Turn test on a force plate compared with their healthy counterparts. [Conclusion] Both static and dynamic postural stability parameters are affected in hemiplegic cerebral palsy. Further research is needed to define rehabilitation interventions to improve these parameters in patients. PMID:27313338

  10. Comparative nonlinear modeling of renal autoregulation in rats: Volterra approach versus artificial neural networks

    DEFF Research Database (Denmark)

    Chon, K H; Holstein-Rathlou, N H; Marsh, D J;

    1998-01-01

    kernel estimation method based on Laguerre expansions. The results for the two types of artificial neural networks and the Volterra models are comparable in terms of normalized mean square error (NMSE) of the respective output prediction for independent testing data. However, the Volterra models obtained......In this paper, feedforward neural networks with two types of activation functions (sigmoidal and polynomial) are utilized for modeling the nonlinear dynamic relation between renal blood pressure and flow data, and their performance is compared to Volterra models obtained by use of the leading...... via the Laguerre expansion technique achieve this prediction NMSE with approximately half the number of free parameters relative to either neural-network model. However, both approaches are deemed effective in modeling nonlinear dynamic systems and their cooperative use is recommended in general....

  11. Ultrasonographic evaluation of cerebral arterial and venous haemodynamics in multiple sclerosis: a case-control study.

    Directory of Open Access Journals (Sweden)

    Pasquale Marchione

    Full Text Available OBJECTIVE: Although recent studies excluded an association between Chronic Cerebrospinal Venous Insufficiency and Multiple Sclerosis (MS, controversial results account for some cerebrovascular haemodynamic impairment suggesting a dysfunction of cerebral autoregulation mechanisms. The aim of this cross-sectional, case-control study is to evaluate cerebral arterial inflow and venous outflow by means of a non-invasive ultrasound procedure in Relapsing Remitting (RR, Primary Progressive (PP Multiple Sclerosis and age and sex-matched controls subjects. MATERIAL AND METHODS: All subjects underwent a complete extra-intracranial arterial and venous ultrasound assessment with a color-coded duplex sonography scanner and a transcranial doppler equipment, in both supine and sitting position by means of a tilting chair. Basal arterial and venous morphology and flow velocities, postural changes in mean flow velocities (MFV of middle cerebral arteries (MCA, differences between cerebral venous outflow (CVF in clinostatism and in the seated position (ΔCVF and non-invasive cerebral perfusion pressure (CPP were evaluated. RESULTS: 85 RR-MS, 83 PP-MS and 82 healthy controls were included. ΔCVF was negative in 45/85 (52.9% RR-MS, 63/83 (75.9% PP-MS (p = 0.01 and 11/82 (13.4% controls (p<0.001, while MFVs on both MCAs in sitting position were significantly reduced in RR-MS and PP-MS patients than in control, particularly in EDSS ≥ 5 subgroup (respectively, 42/50, 84% vs. 66/131, 50.3%, p<0.01 and 48.3 ± 2 cm/s vs. 54.6 ± 3 cm/s, p = 0.01. No significant differences in CPP were observed within and between groups. CONCLUSIONS: The quantitative evaluation of cerebral blood flow (CBF and CVF and their postural dependency may be related to a dysfunction of autonomic nervous system that seems to characterize more disabled MS patients. It's not clear whether the altered postural control of arterial inflow and venous outflow is a specific MS condition or simply an

  12. Recurrent cerebral thrombosis

    International Nuclear Information System (INIS)

    Neuroradiological techniques were used to elucidate pathophysiology of recurrent cerebral thrombosis. Twenty-two patients with cerebral thrombosis who suffered a second attack under stable conditions more than 22 days after the initial stroke were studied. Hypertension, diabetes mellitus, and hypercholesterolemia were also seen in 20, 8, and 12 patients, respectively. The patients were divided into three groups according to their symptoms: (I) symptoms differed between the first and second strokes (n=12); (II) initial symptoms were suddenly deteriorated (n=6); and (III) symptoms occurring in groups I and II were seen (n=4). In group I, contralateral hemiparesis or suprabulbar palsy was often associated with the initial hemiparesis. The time of recurrent stroke varied from 4 months to 9 years. CT and MRI showed not only lacunae in both hemispheres, but also deep white-matter ischemia of the centrum semi-ovale. In group II, hemiparesis or visual field defect was deteriorated early after the initial stroke. In addition, neuroimaging revealed that infarction in the posterior cerebral artery was progressed on the contralateral side, or that white matter lesion in the middle artery was enlarged in spite of small lesion in the left cerebral hemisphere. All patients in group III had deterioration of right hemiparesis associated with aphasia. CT, MRI, SPECT, and angiography indicated deep white-matter ischemia caused by main trunk lesions in the left hemisphere. Group III seemed to be equivalent to group II, except for laterality of the lesion. Neuroradiological assessment of the initial stroke may help to predict the mode of recurrence, although pathophysiology of cerebral thrombosis is complicated and varies from patient to patient. (N.K.)

  13. Dynamic changes of apoptosis in rat cerebral cortex neurons after hypoxia%大鼠大脑皮层神经元缺氧后细胞凋亡情况的动态观察

    Institute of Scientific and Technical Information of China (English)

    邹哲华; 陶陶; 徐坚; 刘智; 罗开俭

    2012-01-01

    Objective To observe the dynamic changes of apoptosis in rat cerebral cortex neurons after hypoxia. Methods Rat cerebral cortex neurons were primarily cultured from SD rats born within 24 h and then identified by immunocytochemical assay. Then the identified cells were cultured in the medium containing 100 μmol/L CoCl2 to simulate hypoxic condition. The cells cultivated in normal condition served as normal control ( normoxia group). Ultrastructural changes of the neurons were observed by transmission electron microscopy (TEM) . Neuronal apoptosis were observed by TUNEL assay. Results TEM displayed that the morphology of neurons was normal, so was the structure of chromatin, endoplasmic reticulum and mitochondria in normoxia group, while, cellular edema, organelle damage or disappearance were seen in the hypoxia group. TUNEL showed that obvious apoptosis were found in hypoxic cells, with significant difference with normoxia group ( P < 0. 01). The apoptosis reached its peak in 48 h after hypoxia (0. 187 ±0. 007) , significantly higher than those in 12, 24 and 72 h (P <0. 01). Conclusion Apoptosis is a dynamic process in hypoxic-ischemic brain injury, and an important pattern of neuronal death. Intervention for neuronal apoptosis should be performed in an appropriate time window to effectively treat hypoxic-ischemic encephalopathy.%目的 观察大鼠大脑皮层神经元缺氧后细胞凋亡动态变化.方法 制备大鼠大脑皮层神经元体外原代培养模型,免疫细胞化学鉴定大鼠大脑皮层神经元,透射电镜下观察不同时间点各实验组神经元超微结构的变化,TUNEL法观察不同时间点各实验组神经元凋亡情况.结果 正常对照组神经元透射电镜下形态及染色质正常、内质网、线粒体等结构正常,缺氧组神经元水肿,细胞器破坏或消失;TUNEL法检测神经元凋亡:缺氧后各组神经元凋亡明显增加,与相应正常对照组相比有显著差异(P<0.01),缺氧48 h

  14. Diagnostic examination performance by using microvascular leakage, cerebral blood volume, and blood flow derived from 3-T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in the differentiation of glioblastoma multiforme and brain metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Server, Andres; Nakstad, Per H. [Oslo University Hospital-Ullevaal, Section of Neuroradiology, Department of Radiology and Nuclear Medicine, Oslo (Norway); University of Oslo, Oslo (Norway); Orheim, Tone E.D. [Oslo University Hospital, Interventional Centre, Oslo (Norway); Graff, Bjoern A. [Oslo University Hospital-Ullevaal, Department of Radiology and Nuclear Medicine, Oslo (Norway); Josefsen, Roger [Oslo University Hospital-Ullevaal, Department of Neurosurgery, Oslo (Norway); Kumar, Theresa [Oslo University Hospital-Ullevaal, Department of Pathology, Oslo (Norway)

    2011-05-15

    Conventional magnetic resonance (MR) imaging has limited capacity to differentiate between glioblastoma multiforme (GBM) and metastasis. The purposes of this study were: (1) to compare microvascular leakage (MVL), cerebral blood volume (CBV), and blood flow (CBF) in the distinction of metastasis from GBM using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MRI), and (2) to estimate the diagnostic accuracy of perfusion and permeability MR imaging. A prospective study of 61 patients (40 GBMs and 21 metastases) was performed at 3 T using DSC-MRI. Normalized rCBV and rCBF from tumoral (rCBVt, rCBFt), peri-enhancing region (rCBVe, rCBFe), and by dividing the value in the tumor by the value in the peri-enhancing region (rCBVt/e, rCBFt/e), as well as MVL were calculated. Hemodynamic and histopathologic variables were analyzed statistically and Spearman/Pearson correlations. Receiver operating characteristic curve analysis was performed for each of the variables. The rCBVe, rCBFe, and MVL were significantly greater in GBMs compared with those of metastases. The optimal cutoff value for differentiating GBM from metastasis was 0.80 which implies a sensitivity of 95%, a specificity of 92%, a positive predictive value of 86%, and a negative predictive value of 97% for rCBVe ratio. We found a modest correlation between rCBVt and rCBFt ratios. MVL measurements in GBMs are significantly higher than those in metastases. Statistically, both rCBVe, rCBVt/e and rCBFe, rCBFt/e were useful in differentiating between GBMs and metastases, supporting the hypothesis that perfusion MR imaging can detect infiltration of tumor cells in the peri-enhancing region. (orig.)

  15. Modified GFAP promoter auto-regulates tet-activator expression for increased transactivation and reduced tTA-associated toxicity.

    Science.gov (United States)

    Barton, Michael D; Dunlop, J W; Psaltis, G; Kulik, J; DeGennaro, L; Kwak, Seung P

    2002-05-30

    Transactivator tTA is a necessary component of the tetracycline-regulated inducible gene system. While several transgenic animals have been described that express tTA in the central nervous system (CNS), their tTA levels are often limited, presumably due to toxic effects. We evaluated methods for auto-regulating tTA levels in astrocytes by modifying the transgenic promoter human GFAP (hGFAP). The hGFAP promoter carrying a single copy of the tet-operon in place of a native enhancer element (GFAPtetO1) drove expression of tTA at low levels during un-stimulated, basal condition. However the same promoter auto-induced expression of tTA to significant levels after tetracycline withdrawal. Glial cell-specificity of the promoter remained uncompromised during both basal and induced conditions. Transgenic rats were developed using the auto-inducible GFAPtetO1 promoter that expressed tTA mRNA to high levels in the brain. Expression was widespread within the CNS but enriched in astrocyte-rich regions including the cerebellum. Primary cerebellar astrocytes from GFAPtetO1 rats transfected with 07LacZ produced substantially greater inducibility of reporter gene compared to GFAP-tTA transgenic rats. Finally, GFAPtetO1 rats exhibited severe motor/gait deficit when bred to homozygosity. This phenotype was attributable to developmental abnormalities of the cerebellum and was completely abrogated by doxycycline administration. These results suggest that developmental toxicity resulting from tTA expression can be circumvented and tTA transgenics with high transactivation potential can be developed using the auto-activation strategy. Promoter modification presented here may be useful in developing highly inducible transgenic strategies without loss in tissue-specificity. PMID:12007834

  16. A γ-butyrolactone autoregulator-receptor system involved in the regulation of auricin production in Streptomyces aureofaciens CCM 3239.

    Science.gov (United States)

    Mingyar, Erik; Feckova, Lubomira; Novakova, Renata; Bekeova, Carmen; Kormanec, Jan

    2015-01-01

    The γ-butyrolactone (GBL) autoregulator-receptor systems play a role in controlling secondary metabolism and/or morphological differentiation in many Streptomyces species. We previously identified the aur1 gene cluster, located on the Streptomyces aureofaciens CCM 3239 large linear plasmid pSA3239, which is responsible for the production of the angucycline antibiotic auricin. Here, we describe the characterisation of two genes, sagA and sagR, encoding GBL autoregulatory signalling homologues, which lie in the upstream part of the aur1 cluster. SagA was similar to GBL synthases and SagR to GBL receptors. The expression of each gene is directed by its own promoter, sagAp for sagA and sagRp for sagR. Both genes were active mainly during the exponential phase, and their transcription was interdependent. The disruption of sagA abolished auricin production, while the disruption of sagR resulted in precocious but dramatically reduced auricin production. Transcription from the aur1Pp and aur1Rp promoters, which direct the expression of auricin-specific cluster-situated regulators (CSRs), was also precocious and increased in the sagR mutant strain. In addition, SagR was also shown to specifically bind both promoters in vitro. These results indicated that the SagA-SagR GBL system regulates auricin production. Unlike many other GBL receptors, SagR does not bind its own promoter, but Aur1R, an auricin-specific repressor from the family of pseudo GBL receptors, does bind both sagAp and sagRp promoters. Moreover, the expression of both promoters was deregulated in an aur1R mutant, indicating that the SagA-SagR GBL system is regulated by a feedback mechanism involving the auricin-specific CSR Aur1R, which regulates downstream. PMID:25219533

  17. Neural perspectives of cerebral correlates of giftedness.

    Science.gov (United States)

    Chen, A C; Buckley, K C

    1988-07-01

    Giftedness is defined as some special endowment or propensity for creativity, skill, and eminent achievement, found in relatively few individuals among the population. A high order of mental power (IQ), creativity, and motivation (task commitment) appear to be the most universally recognized attributes of the gifted. This report summarizes current knowledge of the cerebral correlates of intelligence and creativity, including physiological measures of EEG, cortical power spectrum, brain evoked potentials, and positron emission tomography. Controversy, debates, contentions, formal hypotheses, and research issues are considered. We are especially interested in the formulation of the deterministic function of EEG-brain dynamics. A CHAOS modeling on hierarchy of cognitive organization and cerebral processing in the gifted is suggested.

  18. Parálisis cerebral Cerebral palsy

    Directory of Open Access Journals (Sweden)

    Jorge Malagon Valdez

    2007-01-01

    Full Text Available El término parálisis cerebral (PC engloba a un gran número de síndromes neurológicos clínicos, de etiología diversa. Estos síndromes se caracterizan por tener una sintomatología común: los trastornos motores. Algunos autores prefieren manejar términos como "encefalopatía fija", "encefalopatías no evolutivas". Se mencionan la utilidad de programas de intervención temprana y métodos especiales de rehabilitación, así como el manejo de las deficiencias asociadas como la epilepsia, deficiencia mental, trastornos del lenguaje, audición, visión, déficit de la atención que mejoran el pronóstico de manera significativa. El pronóstico también depende de la gravedad del padecimiento y de las manifestaciones asociadas.The term cerebral palsy (CP, is used for a great number of clinical neurological syndromes. The syndromes are characterized by having a common cause, motor defects. It is important, because they can cause a brain damage by presenting motor defects and some associated deficiencies, such as mental deficiency, epilepsy, language and visual defects and pseudobulbar paralysis, with the nonevolving fact. Some authors prefer using terms such as "non-evolving encephalopathies". In the treatment the utility of prevention programs of early stimulation and special rehabilitation methods, and treatment of associated deficiencies such as epilepsy, mental deficiency, language, audition and visual problems, and the attention deficit improve the prognosis in an important way. The prognosis depends on the severity of the disease and the associated manifestations.

  19. Music and cerebral hemodynamics.

    Science.gov (United States)

    Marinoni, M; Grassi, E; Latorraca, S; Caruso, A; Sorbi, S

    2000-09-01

    Previous studies performed by positron emission tomography and Transcranial Doppler (TCD) found a different cerebral activation during musical stimuli in musicians compared to non-musicians. The aim of our study is to evaluate by means of TCD, possible different pattern of cerebral activation during the performance of different musical tasks in musicians, non-musicians and lyrical singers. Our findings show a left hemispheric activation in musicians and a right one in non-musicians. Preliminary data on lyrical singers' activation patterns need further confirmation with a larger population. These data could be related to a different approach to music listening in musicians (analytical) and non-musicians who are supposed to have an emotional approach to music. PMID:10942664

  20. 老年高血压患者动态血压特点及其与脑卒中关系%The Dynamic Blood Pressure Characteristics of Elderly Hypertensive Patients and Its Relationship with Cerebral Apoplexy

    Institute of Scientific and Technical Information of China (English)

    黄万慧

    2014-01-01

    To study the dynamic blood pressure characteristics of elderly hypertensive patients and its relationship with cerebral apoplexy.Method:267 hypertension patients were selected as the research object in our hospital from February 2013 to February 2014,they were divided into the elderly group(the group A,149 patients)and the non-elderly group(the group B,118 patients)according to patients’ age. On the basis of this group again,according to whether patients with combined stroke will be divided into the stroke group A1 and B1 and the non-stroke group A2 and B2. Ambulatory blood pressure of 267 cases were monitored,the blood pressure characteristics two groups was observed and its relationship with cerebral apoplexy was analyzed.Result:In the group A whether merger or stroke,its blood pressure circadian rhythm was lower than that in the group B(P<0.05);the pulse pressure pulse pressure had significant difference between the group A and the group B(P<0.05). Nighttime systolic blood pressure of the A1 group was obviously higher than that of the rest of the three groups(P<0.05).Conclusion:Low blood pressure circadian rhythm,pressing of arteries and veins increases blood pressure and systolic blood pressure at night increased dynamic is one of the reasons for the elderly patients with hypertension complicated by stroke,to analyze the change characteristics of senile hypertension and its and the relationship between cerebral apoplexy can effectively prevent the disease caused by cardiovascular disease, and through the individual treatment plan to ensure the clinical therapeutic effect.%目的:探讨老年高血压患者动态血压特点与脑卒中的关系。方法:选择2013年2月-2014年2月本院收治的267例高血压患者作为研究对象,根据患者的年龄将其分为老年组149例(A组)和非老年组118例(B组)。在此基础上再次进行分组,根据患者是否合并脑卒中将上述两组分为脑卒中组A1和B1

  1. Dysphagia in cerebral palsy

    OpenAIRE

    Salghetti, Annamaria; Martinuzzi, Andrea

    2013-01-01

    Abstract. Feeding problemsare often present in children with neuromotor impairment: dysphagia is usuallyseen in the most severe form of cerebral palsy and it’s defined as thedifficulty with any of the four phases of swallowing. Clinical consequences aremalnutrition and recurrent chest infections that reduce expected duration andquality of life. In order to prevent these consequences it’s important todetect with clinical and instrumental examinations dysphagia symptoms and totreat them. Clinic...

  2. Nanomedicine in cerebral palsy

    OpenAIRE

    Balakrishnan B; Nance E; Johnston MV; Kannan R; Kannan S

    2013-01-01

    Bindu Balakrishnan,1 Elizabeth Nance,1 Michael V Johnston,2 Rangaramanujam Kannan,3 Sujatha Kannan1 1Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University; Baltimore, MD, USA; 2Department of Neurology and Pediatrics, Kennedy Krieger Institute, Baltimore, MD, USA; 3Department of Ophthalmology, Center for Nanomedicine, Johns Hopkins University, Baltimore, MD, USA Abstract: Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the...

  3. Phenylpropanolamine and cerebral hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, J.R.; LeBlanc, H.J.

    1985-05-01

    Computerized tomography, carotid angiograms, and arteriography were used to diagnose several cases of cerebral hemorrhage following the use of phenylpropanolamine. The angiographic picture in one of the three cases was similar to that previously described in association with amphetamine abuse and pseudoephedrine overdose, both substances being chemically and pharmacologically similar to phenylpropanolamine. The study suggests that the arterial change responsible for symptoms may be due to spasm rather than arteriopathy. 14 references, 5 figures.

  4. Radiopharmaceuticals for cerebral studies

    International Nuclear Information System (INIS)

    For obtain good brain scintillation images in nuclear medicine must be used several radiopharmaceuticals. Cerebral studies give a tumors visual image as well as brain anomalities detection and are helpful in the diagnostic diseases . Are described in this work: a cerebrum radiopharmaceuticals classification,labelled compounds proceeding and Tc 99m good properties in for your fast caption, post administration and blood purification for renal way

  5. Phenylpropanolamine and cerebral hemorrhage

    International Nuclear Information System (INIS)

    Computerized tomography, carotid angiograms, and arteriography were used to diagnose several cases of cerebral hemorrhage following the use of phenylpropanolamine. The angiographic picture in one of the three cases was similar to that previously described in association with amphetamine abuse and pseudoephedrine overdose, both substances being chemically and pharmacologically similar to phenylpropanolamine. The study suggests that the arterial change responsible for symptoms may be due to spasm rather than arteriopathy. 14 references, 5 figures

  6. [Insomnia and cerebral hypoperfusion].

    Science.gov (United States)

    Káposzta, Zoltán; Rácz, Klára

    2007-11-18

    Insomnia is defined as difficulty with the initiation, maintenance, duration, or quality of sleep that results in the impairment of daytime functioning, despite adequate opportunity and circumstances for sleep. In most countries approximately every third inhabitant has insomnia. Insomnia can be classified as primary and secondary. The pathogenesis of primary insomnia is unknown, but available evidence suggests a state of hyperarousal. Insomnia secondary to other causes is more common than primary insomnia. Cerebral hypoperfusion can be the cause of insomnia in some cases. In such patients the cerebral blood flow should be improved using parenteral vascular therapy. If insomnia persists despite treatment, then therapy for primary insomnia should be instituted using benzodiazepine-receptor agonists such as Zolpidem, Zopiclone, or Zaleplon. In those cases Midazolam cannot be used for the treatment of insomnia due to its marked negative effect on cerebral blood flow. In Hungary there is a need to organize multidisciplinary Insomnia Clinics because insomnia is more than a disease, it is a public health problem in this century. PMID:17988972

  7. Cerebral malformations without antenatal diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Nadine J. [Diagnostic Neuroradiology, Hopital Timone, Marseille (France)

    2010-06-15

    Cerebral malformations are usually described following the different steps in development. Disorders of neurulation (dysraphisms), or diverticulation (holoprosencephalies and posterior fossa cysts), and total commissural agenesis are usually diagnosed in utero. In contrast, disorders of histogenesis (proliferation-differentiation, migration, organization) are usually discovered in infants and children. The principal clinical symptoms that may be a clue to cerebral malformation include congenital hemiparesis, epilepsy and mental or psychomotor retardation. MRI is the imaging method of choice to assess cerebral malformations. (orig.)

  8. La parálisis cerebral como una condición dinámica del cerebro: un estudio secuencial del desarrollo de niños hasta los 6 años de edad / Cerebral Palsy as a Dynamic Condition of the Brain: A Sequential Study of the Development of Children up to 6 Years of Age

    Directory of Open Access Journals (Sweden)

    Enrique Moraleda Barreno

    2013-03-01

    Full Text Available La parálisis cerebral es un trastorno motor debido a inmadurez cerebral con numerosos déficits asociados, incluidos los adaptativos, sociales, motores, cognitivos y de la comunicación, y con gran impacto en el desarrollo. El objetivo del presente estudio fue estudiar el desarrollo durante un año de niños con parálisis cerebral de uno a seis años. El método empleado fue un diseño ex post facto evolutivo secuencial. Se utilizó la prueba de screening del Inventario de Desarrollo de Battelle en un pretest y en un postest transcurrido un año. La muestra estuvo compuesta por 41 niños de entre 1 y 6 años de edad con diagnóstico de parálisis cerebral infantil. Los niños mostraban puntuaciones en el postest significativamente superiores en todas las áreas estudiadas. Se observó una mejora generalizada en las capacidades de la mayoría de los sujetos. Se discuten las posibles influencias que contribuyen a estas mejoras en los cocientes de desarrollo en la obtención de estos resultados.

  9. Comparison of Two Algorithms for Analysis of Perfusion Computed Tomography Data for Evaluation of Cerebral Microcirculation in Chronic Subdural Hematoma.

    Science.gov (United States)

    Trofimov, Alexey O; Kalentiev, George; Voennov, Oleg; Yuriev, Michail; Agarkova, Darya; Trofimova, Svetlana; Bragin, Denis E

    2016-01-01

    The aim of this work was comparison of two algorithms of perfusion computed tomography (PCT) data analysis for evaluation of cerebral microcirculation in the perifocal zone of chronic subdural hematoma (CSDH). Twenty patients with CSDH after polytrauma were included in the study. The same PCT data were assessed quantitatively in cortical brain region beneath the CSDH (zone 1), and in the corresponding contralateral brain hemisphere (zone 2) without and with the use of perfusion calculation mode excluding vascular pixel 'Remote Vessels' (RV); 1st and 2nd analysis method, respectively. Comparison with normal values for perfusion indices in the zone 1 in the 1st analysis method showed a significant (p < 0.01) increase in CBV and CBF, and no significant increase in MTT and TTP. Use of the RV mode (2nd analysis method) showed no statistically reliable change of perfusion parameters in the microcirculatory blood flow of the 2nd zone. Maintenance of microcirculatory blood flow perfusion reflects the preservation of cerebral blood flow autoregulation in patients with CSDH. PMID:27526170

  10. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H;

    2014-01-01

    This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon di...

  11. Cerebral Hemorrhage and APOE genotype

    Institute of Scientific and Technical Information of China (English)

    Sun xiaojiang; Wu ping; Zhang jing; Lu shanqing; Li bing

    2000-01-01

    Background and Purpose: Current evidence Suggests that the apolipoprotein E (APOE)ε 4 allele predisposes to cerebral amyloid angiopathy (CAA) whereas ε 2 is associated with CAA-zelated hemorrhage. In this study we examined potential clinical risk factors inpatients with cerebral hemorrhage and assessed these with respect to APOE genotype. Methoeds: 146 patinas with cerebral hemorrhage and 70 normal controls were investigated. APOE genotypes were determined with use of polymerase Chain reaction techniques.Results: The frequency of allele gene ( 0.180 ) and the percentage of the APOE ε 4 genotype in the cerebral hemorrhage group were Significantly higher as compared with the e 4 prequency ( O.O72 ) in the control group respectively ( p=O.O389 ) .Conelusious: APOE ε 4 :allele is a risk gene for cerebral hemorrhage.

  12. Therapeutic interventions in cerebral palsy.

    Science.gov (United States)

    Patel, Dilip R

    2005-11-01

    Various therapeutic interventions have been used in the management of children with cerebral palsy. Traditional physiotherapy and occupational therapy are widely used interventions and have been shown to be of benefit in the treatment of cerebral palsy. Evidence in support of the effectiveness of the neurodevelopmental treatment is equivocal at best. There is evidence to support the use and effectiveness of neuromuscular electrical stimulation in children with cerebral palsy. The effectiveness of many other interventions used in the treatment of cerebral palsy has not been clearly established based on well-controlled trials. These include: sensory integration, body-weight support treadmill training, conductive education, constraint-induced therapy, hyperbaric oxygen therapy, and the Vojta method. This article provides an overview of salient aspects of popular interventions used in the management of children with cerebral palsy. PMID:16391455

  13. Gait characteristics of children with spastic cerebral palsy assessed by dynamic plantar pressure measurement%动态足底压力检测痉挛型脑性瘫痪儿童步行时的特征

    Institute of Scientific and Technical Information of China (English)

    李海; 周安艳; 黄东锋; 丁建新; 江沁

    2007-01-01

    典型的双峰曲线,能得到典型足底压力双峰图的儿童,从其足底压力图中提取的各特征量数据能体现患儿步行时步态周期各时期的足底压力特征.%BACKGROUND:Pressure sensitive instrumented shoes are fast and easily used tools to measure ground reaction forces. Currently researches about the utilities of these systems in assessment of gait in children with neurological diseases have been started to run.OBJECTIVE: To find the gait characteristics of dynamic plantar pressure in children with spastic cerebral palsy. DESIGN: A cross-sectional study.SETTINGS: Department of Rehabilitation, Songgang People's Hospital; Department of Rehabilitation, Shenzhen Children's Hospital; Department of Rehabilitation Medicine, the First Affiliated Hospital of Sun Yat-sen University. PARTICIPANTS: ① Patient group: Twenty children with spastic cerebral palsy were selected from Shenzhen Children's Hospital from May 2004 to April 2005, including 9 boys and 11 girls, aged 26-66 months old, and they all could walk for more than 10 m independently. ② Normal control group: 52 healthy children with normal walking ability were enrolled, including 28 boys.and 24 girls, aged 35-76 months old.METHODS: Ultraflex gait analysis system was used to perform continuous plantar pressure tests of both groups of children. Diagram and data of dynamic plantar pressures in gait were recorded and analyzed with a computer. MAIN OUTCOME MEASURES: ① 10 sequential gait cycles were chosen from the continuous stable steps to calculate the average data with the software; ② Differences of the characteristic parameters of plantar pressure curve between the two groups.RESULTS: ① The curves of plantar pressure to time of testees in the normal control group were of the wave shapes with two peaks and one valley. Half of the CP children could not perform the two-peak shape pressure curve in the gait analysis. One kind of abnormal plantar pressure curve style was a wave shape

  14. Cerebral imaging in pediatrics

    International Nuclear Information System (INIS)

    Radioisotope brain imaging has focused mainly on regional cerebral blood flow (rCBF). However the use of ligand which go to specific receptor sites is being introduced in pediatrics, mainly psychiatry. rCBF is potentially available in many institutions, especially with the availability of multi-headed gamma cameras. The use of this technique in pediatrics requires special attention to detail in the manner of data acquisition and handling the child. The interpretation of the rCBF study in a child requires knowledge of normal brain maturation. The major clinical use in pediatrics is epilepsy because of the advances in surgery and the frequency of complex partial seizures. Other indications in pediatric neurology include brain death, acute neurological loss including stroke, language disorders, cerebral palsy, hypertension due to renovascular disease, traumatic brain injury and migraine. There are pediatric physiological conditions in which rCBF has been undertaken, these include anorexia nervosa, autism, Gilles de la Tourette syndrome (GTS) and attention deficit disorder-hyperactivity (ADHD). Research using different ligands to specific receptor sites will also be reviewed in pediatrics

  15. Cerebral sinus venous thrombosis

    Directory of Open Access Journals (Sweden)

    Hernando Raphael Alvis-Miranda

    2013-01-01

    Full Text Available Cerebral sinus venous thrombosis (CSVT is a rare phenomenon that can be seen with some frequency in young patients. CSVT is a multifactorial condition with gender-related specific causes, with a wide clinical presentation, the leading causes differ between developed and developing countries, converting CSVT in a condition characterized by a highly variable clinical spectra, difficult diagnosis, variable etiologies and prognosis that requires fine medical skills and a high suspicious index. Patients who presents with CSVT should underwent to CT-scan venography (CVT and to the proper inquiry of the generating cause. This disease can affect the cerebral venous drainage and related anatomical structure. The symptoms may appear in relation to increased intracranial pressure imitating a pseudotumorcerebri. Prognosis depends on the early detection. Correcting the cause, generally the complications can be prevented. Mortality trends have diminished, and with the new technologies, surely it will continue. This work aims to review current knowledge about CSVT including its pathogenesis, etiology, clinical manifestations, diagnosis, and treatment.

  16. Cerebral imaging in pediatrics

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, I. [London, Great Ormond Street Hospital for Children (United Kingdom)

    1998-06-01

    Radioisotope brain imaging has focused mainly on regional cerebral blood flow (rCBF). However the use of ligand which go to specific receptor sites is being introduced in pediatrics, mainly psychiatry. rCBF is potentially available in many institutions, especially with the availability of multi-headed gamma cameras. The use of this technique in pediatrics requires special attention to detail in the manner of data acquisition and handling the child. The interpretation of the rCBF study in a child requires knowledge of normal brain maturation. The major clinical use in pediatrics is epilepsy because of the advances in surgery and the frequency of complex partial seizures. Other indications in pediatric neurology include brain death, acute neurological loss including stroke, language disorders, cerebral palsy, hypertension due to renovascular disease, traumatic brain injury and migraine. There are pediatric physiological conditions in which rCBF has been undertaken, these include anorexia nervosa, autism, Gilles de la Tourette syndrome (GTS) and attention deficit disorder-hyperactivity (ADHD). Research using different ligands to specific receptor sites will also be reviewed in pediatrics.

  17. Biomechanical bases of rehabilitation of children with cerebral palsy

    Science.gov (United States)

    Davlet'yarova, K. V.; Korshunov, S. D.; Kapilevich, L. V.

    2015-11-01

    Biomechanical analysis and the study results of children's with cerebral palsy (CP) muscles bioelectrical activity while walking on a flat surface are represented. Increased flexion in the hip and shoulder joints and extension in the elbow joint in children with cerebral palsy were observed, with the movement of the lower limbs had less smooth character in comparison with the control group. Herewith, the oscillation amplitude was significantly increased, and the frequency in the m. gastrocnemius and m. lateralis was decreased. It was shown, that the dynamic stereotype of walking in children with cerebral palsy was characterized by excessive involvement of m. gastrocnemius and m.latissimus dorsi in locomotion. Thus, resulting biomechanical and bioelectrical parameters of walking should be considered in the rehabilitation programs development.

  18. CEREBRAL PALSY AND MUSIC ACHIEVEMENT

    Directory of Open Access Journals (Sweden)

    Miodrag L. STOSHLJEVIKJ

    2008-12-01

    Full Text Available Pupils with cerebral palsy attend elementary education accordind to a regular and special teaching plan and program. Regular school curriculum was reformed in 1992, while special plan and program has not been changed and adapted according to pupil’s needs and capacities. Music is one of the best means of expressing oneself and plays a very important role in the development of every child, the child with cerebral palsy in particular.In order to test the possibility of pupils with cerebral palsy, with and without mental retardation, to apprehend the actual program content, we have conducted research on musical achievement of children with cerebral palsy. During 2007 a research was carried out, on the sample of 27 pupils with cerebral palsy and mild mental retardation who attended classes in the school “Miodrag Matikj”, and a sample of16 students with cerebral palsy without mental retardation who attended the school “Dr. Dragan Hercog” in Belgrade.Results of the research, as well as analysis of music curriculum content, indicated that the capacities of students with cerebral palsy to carry out the curriculum tasks require special approach and methodology. Therefore, we introduced some proposals to overcome the difficulties in fulfilling music curriculum demands of those pupils. We made special emphasis on the use of computer based Assistive technology which facilitates the whole process to a large extent.

  19. CEREBRAL PALSY : ANTENATAL RISK FACTORS

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao

    2015-05-01

    Full Text Available INTRODUCTION: Cerebral palsy (CP is a group of permanent movement disorders that appear in early childhood. Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often the problems occur during pregnancy; however, they may also occur during childbirth, or shortly after birth. Often the cause is unknown. AIM: To study the different antenatal maternal risk factors associated with cerebral palsy in the study group. MATERIA LS AND METHODS: Retrospective study was done to assess possible associated antenatal risk factors for cerebral palsy. Mothers of 100 cerebral palsy children were selected who are treated in Rani Chandramani Devi Hospital, a Government hospital in Visakhapa tn am, Andhra Pradesh State, India , from 2012 to 2014 and 100 controls, mothers of normal children were studied. Detailed antenatal history was obtained from the mothers of the children in both affected and control group. RESULTS: From the data, we conclude that the association of maternal anaemia with cerebral palsy is 7.3 times higher; association of maternal hypertension with cerebral palsy is 6.6 time higher, association with Pre - eclampsia is 6 times higher; association with Eclampsia is 8.6 times higher ; with antepartum haemorrhage, the association is 8.6 times higher and association of multiple pregnancy with cerebral palsy is 4.8 times higher than with controls. CONCLUSION: From this study of the role of antenatal risk factors, in the occurrence of cer ebral palsy in children it is concluded that the most common risk factor associated with cerebral palsy is the maternal anaemia and the other important risk factors associated being hypertension, pre eclampsia, eclampsia, antepartum haemorrhage and multipl e births.

  20. Transient cerebral hypoperfusion and hypertensive events during atrial fibrillation: a plausible mechanism for cognitive impairment

    CERN Document Server

    Anselmino, Matteo; Saglietto, Andrea; Gaita, Fiorenzo; Ridolfi, Luca

    2016-01-01

    Atrial fibrillation (AF) is associated with an increased risk of dementia and cognitive decline, independent of strokes. Several mechanisms have been proposed to explain this association, but altered cerebral blood flow dynamics during AF has been poorly investigated: in particular, it is unknown how AF influences hemodynamic parameters of the distal cerebral circulation, at the arteriolar and capillary level. Two coupled lumped-parameter models (systemic and cerebrovascular circulations, respectively) were here used to simulate sinus rhythm (SR) and AF. For each simulation 5000 cardiac cycles were analyzed and cerebral hemodynamic parameters were calculated. With respect to SR, AF triggered a higher variability of the cerebral hemodynamic variables which increases proceeding towards the distal circulation, reaching the maximum extent at the arteriolar and capillary levels. This variability led to critical cerebral hemodynamic events of excessive pressure or reduced blood flow: 303 hypoperfusions occurred at ...

  1. CEREBRAL PALSY AND MUSIC ACHIEVEMENT

    OpenAIRE

    Miodrag L. STOSHLJEVIKJ; EMINOVIKJ Fadilj N.; NIKIKJ Radmila M.; Gordana I. ACHIKJ; Sanela R. PACIKJ

    2015-01-01

    Pupils with cerebral palsy attend elementary education accordind to a regular and special teaching plan and program. Regular school curriculum was reformed in 1992, while special plan and program has not been changed and adapted according to pupil’s needs and capacities. Music is one of the best means of expressing oneself and plays a very important role in the development of every child, the child with cerebral palsy in particular.In order to test the possibility of pupils with cerebral pal...

  2. Pentosan polysulfate treatment preserves renal autoregulation in ANG II-infused hypertensive rats via normalization of P2X1 receptor activation.

    Science.gov (United States)

    Guan, Zhengrong; Fuller, Barry S; Yamamoto, Tatsuo; Cook, Anthony K; Pollock, Jennifer S; Inscho, Edward W

    2010-05-01

    Inflammatory factors are elevated in animal and human subjects with hypertension and renal injury. We hypothesized that inflammation contributes to hypertension-induced renal injury by impairing autoregulation and microvascular reactivity to P2X(1) receptor activation. Studies were conducted in vitro using the blood-perfused juxtamedullary nephron preparation. Rats receiving ANG II (60 ng/min) infusion were treated with the anti-inflammatory agent pentosan polysulfate (PPS) for 14 days. The magnitude and progression of hypertension were similar in ANG II and ANG II+PPS-treated rats (169 ± 5 vs. 172 ± 2 mmHg). Afferent arterioles from control rats exhibited normal autoregulatory behavior with diameter decreasing from 18.4 ± 1.6 to 11.4 ± 1.7 μm when perfusion pressure was increased from 70 to 160 mmHg. In contrast, pressure-mediated vasoconstriction was markedly attenuated in ANG II-treated rats, and diameter remained essentially unchanged over the range of perfusion pressures. However, ANG II-treated rats receiving PPS exhibited normal autoregulatory behavior compared with ANG II alone rats. Arteriolar reactivity to ATP and β,γ-methylene ATP was significantly reduced in ANG II hypertensive rats compared with controls. Interestingly, PPS treatment preserved normal reactivity to P2 and P2X(1) receptor agonists despite the persistent hypertension. The maximal vasoconstriction was 79 ± 3 and 81 ± 2% of the control diameter for ATP and β,γ-methylene ATP, respectively, similar to responses in control rats. PPS treatment significantly reduced α-smooth muscle actin staining in afferent arterioles and plasma transforming growth factor-β1 concentration in ANG II-treated rats. In conclusion, PPS normalizes autoregulation without altering ANG II-induced hypertension, suggesting that inflammatory processes reduce P2X(1) receptor reactivity and thereby impair autoregulatory behavior in ANG II hypertensive rats.

  3. Autoregulation of PhoP/PhoQ and positive regulation of the cyclic AMP receptor protein-cyclic AMP complex by PhoP in Yersinia pestis.

    Science.gov (United States)

    Zhang, Yiquan; Wang, Li; Han, Yanping; Yan, Yanfeng; Tan, Yafang; Zhou, Lei; Cui, Yujun; Du, Zongmin; Wang, Xiaoyi; Bi, Yujing; Yang, Huiying; Song, Yajun; Zhang, Pingping; Zhou, Dongsheng; Yang, Ruifu

    2013-03-01

    Yersinia pestis is one of the most dangerous bacterial pathogens. PhoP and cyclic AMP receptor protein (CRP) are global regulators of Y. pestis, and they control two distinct regulons that contain multiple virulence-related genes. The PhoP regulator and its cognate sensor PhoQ constitute a two-component regulatory system. The regulatory activity of CRP is triggered only by binding to its cofactor cAMP, which is synthesized from ATP by adenylyl cyclase (encoded by cyaA). However, the association between the two regulatory systems PhoP/PhoQ and CRP-cAMP is still not understood for Y. pestis. In the present work, the four consecutive genes YPO1635, phoP, phoQ, and YPO1632 were found to constitute an operon, YPO1635-phoPQ-YPO1632, transcribed as a single primary RNA, whereas the last three genes comprised another operon, phoPQ-YPO1632, transcribed with two adjacent transcriptional starts. Through direct PhoP-target promoter association, the transcription of these two operons was stimulated and repressed by PhoP, respectively; thus, both positive autoregulation and negative autoregulation of PhoP/PhoQ were detected. In addition, PhoP acted as a direct transcriptional activator of crp and cyaA. The translational/transcriptional start sites, promoter -10 and -35 elements, PhoP sites, and PhoP box-like sequences were determined for these PhoP-dependent genes, providing a map of the PhoP-target promoter interaction. The CRP and PhoP regulons have evolved to merge into a single regulatory cascade in Y. pestis because of the direct regulatory association between PhoP/PhoQ and CRP-cAMP. PMID:23264579

  4. Cerebral blood flow and carbon dioxide reactivity in children with bacterial meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Ashwal, S.; Stringer, W.; Tomasi, L.; Schneider, S.; Thompson, J.; Perkin, R. (Loma Linda Univ. School of Medicine, CA (USA))

    1990-10-01

    We examined total and regional cerebral blood flow (CBF) by stable xenon computed tomography in 20 seriously ill children with acute bacterial meningitis to determine whether CBF was reduced and to examine the changes in CBF during hyperventilation. In 13 children, total CBF was normal (62 +/- 20 ml/min/100 gm) but marked local variability of flow was seen. In five other children, total CBF was significantly reduced (26 +/- 10 ml/min/100 gm; p less than 0.05), with flow reduced more in white matter (8 +/- 5 ml/min/100 gm) than in gray matter (30 +/- 15 ml/min/100 gm). Autoregulation of CBF appeared to be present in these 18 children within a range of mean arterial blood pressure from 56 to 102 mm Hg. In the remaining two infants, brain dead within the first 24 hours, total flow was uniformly absent, averaging 3 +/- 3 ml/min/100 gm. In seven children, CBF was determined at two carbon dioxide tension (PCO2) levels: 40 (+/- 3) mm Hg and 29 (+/- 3) mm Hg. In six children, total CBF decreased 33%, from 52 (+/- 25) to 35 (+/- 15) ml/min/100 gm; the mean percentage of change in CBF per millimeter of mercury of PCO2 was 3.0%. Regional variability of perfusion to changes in PCO2 was marked in all six children. The percentage of change in CBF per millimeter of mercury of PCO2 was similar in frontal gray matter (3.1%) but higher in white matter (4.5%). In the seventh patient a paradoxical response was observed; total and regional CBF increased 25% after hyperventilation. Our findings demonstrate that (1) CBF in children with bacterial meningitis may be substantially decreased globally, with even more variability noted regionally, (2) autoregulation of CBF is preserved, (3) CBF/CO2 responsitivity varies among patients and in different regions of the brain in the same patient, and (4) hyperventilation can reduce CBF below ischemic thresholds.

  5. Cerebral toxoplasmosis in AIDS

    Energy Technology Data Exchange (ETDEWEB)

    Christ, F.; Steudel, H.; Klotz, D.

    1986-02-01

    Since 1982 (Hauser and co-workers), literature has reported focal cerebral tissue charges in AIDS patients whose diagnosis was unclear at first but which could be identified finally as florid toxoplasmosis encephalitis by biopsy and autopsy. It was found that the value of otherwise reliable serological tests (KBR, Sabin-Feldmann tests, etc.) is questionable in patients with severely impaired or incompetent immune systems, and, in particular, that a negative or uncharacteristic test result may not preclude any opportunistic infection process. Furthermore, isolation of Toxoplasma gondii or specific antibodies from the cerebrospinal fluid will be successful in exceptional cases only. In patients with AIDS or lymphadenopathy syndrome, the differential diagnosis will have to include - first and foremost - reactivated toxoplasma infection (not newly acquired, as a rule) if central neurological symptoms occur.

  6. Cerebral white matter hypoplasia

    International Nuclear Information System (INIS)

    This paper demonstrates the MR imaging findings in children with cerebral white matter hypoplasia (CWMH). The MR studies of four children, aged 3-7 y (mean age, 2.3 y) with a diagnosis of CWMH were reviewed. In all cases multiplanar T1-weighted and T2-weighted spin-echo images were obtained. All children had similar histories of severe developmental delay and nonprogressive neurologic deficits despite normal gestational and birth histories. In two cases there was a history of maternal cocaine abuse. Autopsy correlation was available in one child. The MR images of all four children demonstrated diffuse lack of white matter and enlarged ventricles but normal-appearing gray matter. The corpus callosum, although completely formed, was severely thinned. There was no evidence of gliosis or porencephaly, and the distribution of myelin deposition was normal for age in all cases. Autopsy finding in one child correlated exactly with the MR finding

  7. Cerebral oxygenation after birth

    DEFF Research Database (Denmark)

    Hessel, Trine W; Hyttel-Sorensen, Simon; Greisen, Gorm

    2014-01-01

    AIM: To compare absolute values of regional cerebral tissue oxygenation (cStO2 ) during haemodynamic transition after birth and repeatability during steady state for two commercial near-infrared spectroscopy (NIRS) devices. METHODS: In a prospective observational study, the INVOS 5100C and FORE......-SIGHT were compared on 12 term newborns delivered by elective caesarean section. During the 10 min following umbilical cord clamping, cStO2 was measured simultaneously with the neonatal sensors from each device. Repeated measurements were taken the following day. RESULTS: Three and 8 min after clamping......: The INVOS and FORE-SIGHT cStO2 estimates showed oxygenation-level-dependent difference during birth transition. The better repeatability of FORE-SIGHT could be due to the lower response to change in saturation....

  8. Anestesia e paralisia cerebral Anestesia y parálisis cerebral Anesthesia and cerebral palsy

    OpenAIRE

    Március Vinícius M Maranhão

    2005-01-01

    JUSTIFICATIVA E OBJETIVOS: A paralisia cerebral (PC) é uma doença não progressiva decorrente de lesão no sistema nervoso central, levando a um comprometimento motor do paciente. O portador de PC freqüentemente é submetido a procedimentos cirúrgicos devido a doenças usuais e situações particulares decorrentes da paralisia cerebral. Foi objetivo deste artigo revisar aspectos da paralisia cerebral de interesse para o anestesiologista, permitindo um adequado manuseio pré, intra e pós-operatório n...

  9. Learn More About Cerebral Palsy

    Centers for Disease Control (CDC) Podcasts

    2008-03-30

    This podcast describes the causes, preventions, types, and signs and symptoms of cerebral palsy.  Created: 3/30/2008 by National Center on Birth Defects and Developmental Disabilities.   Date Released: 3/21/2008.

  10. 中文版儿童作业疗法认知功能动态评定量表评定脑性瘫痪患儿认知功能的效度研究①%Validity of Dynamic Occupational Therapy Cognitive Assessment for Children on Cognitive Function of Children with Cerebral Pal- sy

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      目的了解中文版儿童作业疗法认知功能动态评定量表(DOTCA-Ch)是否能反映脑瘫患儿的认知功能情况。方法30例脑瘫儿童在1周内由经过培训的康复医学研究生采用DOTCA-Ch和中国比内智力测验分别进行认知功能评定。DOTCA-Ch总分、分测验得分分别与中国比内智力测验得分进行相关性分析。结果 DOTCA-Ch总分、定向和思维操作与IQ值高度相关,空间知觉、运用和视运动组织分测验与IQ值相关度较低。结论 DOTCA-Ch能更全面评定儿童认知功能情况。%Objective To study the validity of Dynamic Occupational Therapy Cognitive Assessment for Children (DOTCA-Ch) on the cognitive function of children with cerebral palsy. Methods 30 children with cerebral palsy were assessed with DOTCA-Ch and Chinese Bi-net Test of Intelligence by trained rehabilitation medicine graduates within 1 week. The correlation between these tests were analyzed. Re-sults The total DOTCA-Ch scores, spatial orientation and thought operation function were strongly correlated with IQ, while spatial percep-tion, praxis and optomotor tissue were slightly correlated with IQ. Conclusion DOTCA-Ch can comprehensively assess the cognitive func-tion of children with cerebral palsy.

  11. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  12. Cerebral small-resistance artery structure and cerebral blood flow in normotensive subjects and hypertensive patients

    Energy Technology Data Exchange (ETDEWEB)

    De Ciuceis, Carolina; Porteri, Enzo; Rizzoni, Damiano; Boari, Gianluca E.M.; Rosei, Enrico Agabiti [University of Brescia, Clinica Medica, Department of Clinical and Experimental Sciences, Brescia (Italy); Cornali, Claudio; Mardighian, Dikran; Fontanella, Marco M. [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Pinardi, Chiara [Spedali Civili, Medical Physics Unit, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Rodella, Luigi F.; Rezzani, Rita [University of Brescia, Section of Anatomy, Department of Clinical and Experimental Sciences, Brescia (Italy); Gasparotti, Roberto [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy)

    2014-12-15

    The aim of this study was to prospectively investigate whether the structure of cerebral small-resistance arteries is related to cerebral perfusion parameters as measured with dynamic susceptibility-weighted contrast magnetic resonance imaging (DSC-MRI) in a selected cohort of hypertensive and normotensive patients. Ten hypertensive and 10 normotensive patients were included in the study. All patients underwent neurosurgical intervention for an intracranial tumor and were investigated with DSC-MRI at 1.5 T. Cerebral small-resistance arteries were dissected from a small portion of morphologically normal cerebral tissue and mounted on an isometric myograph for the measurement of the media-to-lumen (M/L) ratio. A quantitative assessment of cerebral blood flow (CBF) and volume (CBV) was performed with a region-of-interest approach. Correlation coefficients were calculated for normally distributed variables. The institutional review board approved the study, and informed consent was obtained from all patients. Compared with normotensive subjects, hypertensive patients had significantly lower regional CBF (mL/100 g/min) in the cortical grey matter (55.63 ± 1.90 vs 58.37 ± 2.19, p < 0.05), basal ganglia (53.34 ± 4.39 vs 58.22. ± 4.33, p < 0.05), thalami (50.65 ± 3.23 vs 57.56 ± 4.45, p < 0.01), subcortical white matter (19.32 ± 2.54 vs 22.24 ± 1.9, p < 0.05), greater M/L ratio (0.099 ± 0.013 vs 0.085 ± 0.012, p < 0.05), and lower microvessel density (1.66 ± 0.67 vs 2.52 ± 1.28, p < 0.05). A statistically significant negative correlation was observed between M/L ratio of cerebral arteries and CBF in the cortical grey matter (r = -0.516, p < 0.05), basal ganglia (r = -0.521, p < 0.05), thalami (r = -0.527 p < 0.05), and subcortical white matter (r = -0.612, p < 0.01). Our results indicate that microvascular structure might play a role in controlling CBF, with possible clinical consequences. (orig.)

  13. Applications of dynamical systems in biology and medicine

    CERN Document Server

    Radunskaya, Ami

    2015-01-01

    This volume highlights problems from a range of biological and medical applications that can be interpreted as questions about system behavior or control.  Topics include drug resistance in cancer and malaria, biological fluid dynamics, auto-regulation in the kidney, anti-coagulation therapy, evolutionary diversification and photo-transduction.  Mathematical techniques used to describe and investigate these biological and medical problems include ordinary, partial and stochastic differentiation equations, hybrid discrete-continuous approaches, as well as 2 and 3D numerical simulation. .

  14. Gene expression profiling in the human middle cerebral artery after cerebral ischemia.

    Science.gov (United States)

    Vikman, P; Edvinsson, L

    2006-12-01

    We have investigated the gene expression in human middle cerebral artery (MCA) after ischemia. Ischemic stroke affects the perfusion in the affected area and experimental cerebral ischemia results in upregulation of vasopressor receptors in the MCA leading to the ischemic area. We obtained human MCA samples distributing to the ischemic area, 7-10 days post-stroke. The gene expression was examined with real-time polymerase chain reaction (PCR) and microarray, proteins were studied with immunohistochemistry. We investigated genes previously shown to be upregulated in animal models of cerebral ischemia (e.g. ET(A), ET(B), AT1, AT2, and 5-HT(2A/1B/1D)). Their mRNA expression was increased compared with controls, consistent with findings in experimental stroke. Immunohistochemistry showed upregulation of the receptors localized on the smooth muscle cells. The gene expression was profiled with microarray and seven genes chosen for further investigation with real-time PCR; ELK3, LY64, Metallothionin IG, POU3F4, Actin alpha2, RhoA and smoothelin. Six of these were regulated the same way when confirming array expression with real-time PCR. Gene expression studies in the human MCA leading to the ischemic region is similar to that seen after MCA occlusion in rats. We found new genes that support the dynamic changes that occur in the MCA distributing to the ischemic region. PMID:17116215

  15. Cerebral palsy: classification and etiology

    OpenAIRE

    Bialik, Gad M.; Givon, Uri

    2004-01-01

    Cerebral palsy (CP), a common condition of abnormalities in the brain, arises early in life. Since the term was first introduced in 1843, many authors have tried to define and classify CP. The most recent definition was released by the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) in 2005. This article summarizes the latest and familiar classifications of, and etiologies associated with CP.

  16. CEREBRAL PALSY : ANTENATAL RISK FACTORS

    OpenAIRE

    Srinivasa Rao; Vidyullatha; Subbalakshmi

    2015-01-01

    INTRODUCTION: Cerebral palsy (CP) is a group of permanent movement disorders that appear in early childhood. Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often the problems occur during pregnancy; however, they may also occur during childbirth, or shortly after birth. Often the cause is unknown. AIM: To study the different antenatal maternal risk factors associated with cere...

  17. Bone age in cerebral palsy

    OpenAIRE

    Miranda, Eduardo Régis de Alencar Bona; Palmieri, Maurício D'arc; de Assumpção, Rodrigo Montezuma César; Yamada, Helder Henzo; Rancan, Daniela Regina; Fucs, Patrícia Maria de Moraes Barros

    2013-01-01

    Objective To compare the chronological age and bone age among cerebral palsy patients in the outpatient clinic and its correlation with the type of neurological involvement, gender and functional status. Methods 401 patients with spastic cerebral palsy, and ages ranging from three months to 20 years old, submitted to radiological examination for bone age and analyzed by two independent observers according Greulich & Pyle. Results In the topographic distribution, there was a significant delay (p

  18. Sirt1 in cerebral ischemia

    OpenAIRE

    Koronowski, Kevin B.; Perez-Pinzon, Miguel A.

    2015-01-01

    Cerebral ischemia is among the leading causes of death worldwide. It is characterized by a lack of blood flow to the brain that results in cell death and damage, ultimately causing motor, sensory, and cognitive impairments. Today, clinical treatment of cerebral ischemia, mostly stroke and cardiac arrest, is limited and new neuroprotective therapies are desperately needed. The Sirtuin family of oxidized nicotinamide adenine dinucleotide (NAD+)-dependent deacylases has been shown to govern seve...

  19. Cerebral candidiasis. Computed tomography appearance

    Energy Technology Data Exchange (ETDEWEB)

    Chaabane, M.; Ladeb, M.F.; Bouhaouala, M.H.; Ben Hammouda, M.; Ataalah, R.; Gannouni, A.; Krifa, H.

    1989-07-01

    A three year old child who had been suffering from oral candidiasis since the age of 1 year presented with osteitis of the clavicle, 2 cerebral frontal abscesses and an occipital abscess which extended across the calvaria and was associated with osteolysis. Histological and microbiological studies following surgery confirmed the diagnosis of candidiasis in this girl who was found to have IgA immunodefinciency. The authors report the computed tomographic appearance of the cerebral lesions and review the literature. (orig.).

  20. Cerebral candidiasis. Computed tomography appearance

    International Nuclear Information System (INIS)

    A three year old child who had been suffering from oral candidiasis since the age of 1 year presented with osteitis of the clavicle, 2 cerebral frontal abscesses and an occipital abscess which extended across the calvaria and was associated with osteolysis. Histological and microbiological studies following surgery confirmed the diagnosis of candidiasis in this girl who was found to have IgA immunodefinciency. The authors report the computed tomographic appearance of the cerebral lesions and review the literature. (orig.)

  1. Intrathecal treatment of cerebral vasospasm.

    Science.gov (United States)

    Zhang, Yi Ping; Shields, Lisa B E; Yao, Tom L; Dashti, Shervin R; Shields, Christopher B

    2013-11-01

    Treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) remains a major therapeutic challenge. Systemic drug administration is the current treatment of choice, but patients often do not respond beneficially to this approach. Intrathecal (IT) drug administration has several anatomic and pharmacodynamic advantages over conventional systemic treatment of cerebral vasospasm. We reviewed the most recent literature describing IT administration of several drugs to treat aneurysm-induced SAH and cerebral vasospasm, including 16 clinical trials using IT fibrinolytic agents and 10 trials using several IT vasodilators. We evaluated the safety and effectiveness of these trials but made no attempt to perform a meta-analysis using these data. IT drug administration of fibrinolytic agents and vasodilators caused lysis of the subarachnoid clot burden and diminished cerebral vasospasm, respectively. The studies reviewed reported a wide range of drug doses, intervals between aneurysm hemorrhage and initiation of treatment, success of clot dissolution, and degree of vasodilation of vessels in vasospasm. Treatment of vasospasm by IT drug administration is safe and largely effective after the aneurysm has been secured. Our findings indicate that IT treatment effectively delivers a higher drug concentration to vessels in vasospasm with minimal systemic effects. Drugs administered by this route are reported to lyse subarachnoid clots, attenuate cerebral vasospasm, improve clinical outcomes, and decrease the incidence of hydrocephalus. With greater understanding of drug pharmacodynamics, the IT route of drug administration may provide a rational, alternative approach to treating aneurysm-induced cerebral vasospasm. PMID:22651990

  2. Cerebral perfusion and cerebrovascular reactivity are reduced in white matter hyperintensities

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Garde, E; Rostrup, Egill;

    2002-01-01

    reported global reductions in cerebral blood flow (CBF) and cerebral vascular reactivity. In this study, we examined localized hemodynamic status to compare WMH to normal appearing white matter (NAWM). METHODS: A group of 21 normal 85-year-old subjects were studied using dynamic contrast-enhanced MRI...... together with administration of acetazolamide. From a combination of anatomic images with different signal weighting, regions of interest were generated corresponding to gray and white matter and WMH. Localized measurements of CBF and cerebral blood volume (CBV) and mean transit time were obtained directly...

  3. Effects of Hyperglycemia and Effects of Ketosis on Cerebral Perfusion, Cerebral Water Distribution, and Cerebral Metabolism

    OpenAIRE

    Glaser, Nicole; Ngo, Catherine; Anderson, Steven; Yuen, Natalie; Trifu, Alexandra; O’Donnell, Martha

    2012-01-01

    Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], ...

  4. Cerebral edema associated with acute hepatic failure.

    Directory of Open Access Journals (Sweden)

    Fujiwara,Masachika

    1985-02-01

    Full Text Available The clinicopathological findings of cerebral edema were investigated in patients with acute hepatic failure autopsied at Okayama University Hospital between 1970 and 1980 retrospectively. Nine (64% of 14 hepatic failure cases were found to have cerebral edema during a post-mortem examination of the brain. Clinical features of the patients with cerebral edema were not significantly different from those of the patients without cerebral edema. However, general convulsions were observed more frequently in patients later found to have cerebral edema. Moreover, the length of time from deep coma to death was much shorter in the brain edema cases with cerebral herniation than without herniation.

  5. Cerebral trypanosomiasis and AIDS

    Directory of Open Access Journals (Sweden)

    Antunes Apio Claudio Martins

    2002-01-01

    Full Text Available A 36 year-old black female, complaining of headache of one month's duration presented with nausea, vomiting, somnolence, short memory problems, loss of weight, and no fever history. Smoker, intravenous drugs abuser, promiscuous lifestyle. Physical examination: left homonimous hemianopsia, left hemiparesis, no papilledema, diffuse hyperreflexia, slowness of movements. Brain CT scan: tumor-like lesion in the splenium of the corpus calosum, measuring 3.5 x 1.4 cm, with heterogeneous enhancing pattern, sugesting a primary CNS tumor. Due to the possibility of CNS infection, a lumbar puncture disclosed an opening pressure of 380 mmH(20; 11 white cells (lymphocytes; glucose 18 mg/dl (serum glucose 73 mg/dl; proteins 139 mg/dl; presence of Trypanosoma parasites. Serum Elisa-HIV tests turned out to be positive. Treatment with benznidazole dramatically improved clinical and radiographic picture, but the patient died 6 weeks later because of respiratory failure. T. cruzi infection of the CNS is a rare disease, but we have an increasing number of cases in HIV immunecompromised patients. Diagnosis by direct observation of CSF is uncommon, and most of the cases are diagnosed by pathological examination. It is a highly lethal disease, even when properly diagnosed and treated. This article intends to include cerebral trypanosomiasis in the differential diagnosis of intracranial space-occupying lesions, especially in immunecompromised patients from endemic regions.

  6. Asymptomatic ischemic cerebral lesions

    International Nuclear Information System (INIS)

    For the purpose of studying the incidence, pathomorphology and etiology of asymptomatic ischemic cerebral lesions, we carried out a brain MRI study on 65 patients with diabetes mellitus accompanied with hypertension who are thought to belong to a high risk group of ischemic cerebrovascular diseases. Excluding the abnormality of tendon reflex due to diabetic neuropathy, sixty percent of the total patients had some mild neurological signs and symptoms, most of them was discrepancy in tendon reflex. The percentage of the patients in whom MRI disclosed some abnormalities was as high as 70%, they were lacunar stroke, multiple lacunar state, cortical infarct, and patchy high signal lesions visible only in the T2 weighted image. Lacunes or these patchy high signal lesions (considered to be the dilatation of the perivascular space or true lacunes) tended to be found along the border zone or the terminal zone. These results indicate that asymptomatic patients in whom MRI discloses the abnormalities should be considered as candidates for the future onset of multi-infarct. (author)

  7. [Plasma osmolarity and cerebral volume].

    Science.gov (United States)

    Boulard, G

    2001-02-01

    Under normal physiological conditions, the osmolarity of extracellular fluids (ECFs) and natremia are controlled by two regulatory mechanisms modulating the water balance and sodium outflow from information collected by the osmoreceptors and baroreceptors, respectively. As well, under normal physiological conditions, water and electrolytes of brain ECFs are secreted by the endothelial cells of brain capillaries. Furthermore, isotonicity is present on both sides of the blood-brain barrier. In the event of systemic osmolarity disorders, water transport subject to osmosis laws occurs at the level of the blood-brain barrier. In the case of plasmatic hyperosmolarity cerebral dehydration is observed, while cerebral edema occurs in the contrary case. However, plasmatic osmolarity disorders have less effect on the cerebral volume when their introduction is slow. Experimentation in acute conditions shows that measured variations of the cerebral water content are lower than calculated variations, thus suggesting the existence of an adaptive mechanism, that is, the cerebral osmoregulation which limits the variation of the volume of brain cells by modulating their osmoactive molecule content. These osmoactive molecules are, on the one hand, the electrolytes, which are early and rapidly mobilized, and, on the other hand, the organic osmoles (amino acids, etc.), whose secretion is slower and delayed. This phenomenon should be taken into account in the treatment of osmolarity disorders. Thus, the related-risk of treatment for natremia disorders is therapeutic reversal of the osmotic gradient at the level of the blood-brain barrier. This reversal, which corresponds to a second osmotic stress, requires the implementation of a new procedure of cerebral osmoregulation in the opposite direction of the preceding one. As successive osmotic stresses decrease the effectiveness of brain osmoregulation, the risk for cerebral dehydration and pontine myelinolysis increases when the treatment

  8. Dynamic change of cerebral hemodynamic after traumatic brain injury in rats following VEGF-165 gene therapy%VEGF-165基因对创伤性脑损伤脑血流动力学影响的实验研究

    Institute of Scientific and Technical Information of China (English)

    刘科; 唐文渊

    2012-01-01

    Objective To study the exogenous vascular endothelial growth factor (VEGF) gene therapy for traumatic brain injury (TB1) in rats by using CT perfusion (CTP) and to probe into the dynamic changes in local cerebral hemodynamic. Methods TBI rat models were established and were randomly divided into 3 groups, that is, TBI + VEGF group, control group, and TBI group. The expressions of VEGF mRNA in injury area were detected by reverse transcription polymerase chain reaction (RT-PCR) at 1 h, 6 h, 24 h, 3 d, 7 d, 14 d after brain injury. CT perfusion (CTP) at different time points was used to monitor the dynamic changes of the cerebral blood flow (CBV), cerebral blood volume (CBF) and other parameters before and after VEGF-165 gene therapy. Results Integral optical density (IOD) levels in TBI + VEGF group were significant higher than that of TBI and vector control group (P<0.05). CTP parameters and false-color image showed that CBF and CBV was increasing in TBI + VEGF group at 24 h after injury, and at 3 d and 7d after injury the cerebral perfusion was significantly higher in TBI + VEGF group than in TBI group (P <0. 05). At 14 d after injury, CBF and CBV began to decrease, but they were still higher than that of TBI group. Conclusion Exogenous VEGF gene can increase the cerebral perfusion after the traumatic brain injury and improve the microcirculation which provides the basis for the recovery of brain tissues.%目的 研究外源性血管内皮细胞生长因子(VEGF)基因治疗大鼠创伤性脑损伤(TBI)后脑灌注的变化,了解其血流动力学改变.方法 创伤性脑损伤大鼠模型建立后随机分为3组:治疗组,质粒对照组,外伤组.通过RT-PCR检测脑伤后1h、6h、24h、3d、7d、14 d VEGF mRNA在损伤局部的表达改变;应用CT灌注像(CTP)研究不同时间脑血流量(CBF)、脑血容量(CBV)等参数在VEGF-165基因治疗前后的动态变化.结果 VEGF-165基因治疗创伤性脑损伤大鼠后经RT-PCR扩增的VEGF mRNA绝对

  9. 脑血流低灌注老龄大鼠中脑皮质血流的改变与血清总胆固醇和高密度脂蛋白的动态变化%Dynamic changes of cortical blood flow and serum total cholesterol and high density lipoprotein in brains of aging rat during cerebral hypoperfusion

    Institute of Scientific and Technical Information of China (English)

    王林辉; 田茗源; 滕志朋; 王晨; 李昱

    2012-01-01

    目的:通过建立脑血流低灌注模型,观察老龄大鼠脑血流的变化以及在脑血流低灌注下血清中总胆固醇(Total cholesterol,TC)和高密度脂蛋白(High density lipoprotein,HDL)的动态变化.方法:采用持久性双侧颈总动脉结扎法(2Vo)致老龄大鼠脑血流灌注不足,测定术后7、14、21、28d大鼠脑皮质血流;检测、比较术后不同时间段大鼠血清中TC和HDL浓度差异.结果:术后第14天大鼠脑颞区血流出现明显减少;术后21、28d大鼠脑局部皮质血管有再生侧支形成,大鼠脑颞区血流仍未恢复;术后第14天血清中HDL、TC含量明显高于假手术组(P<0.05),随着缺血时间延长,又逐渐降低.结论:血清TC和HDL浓度在脑缺血灌注不足的不同时间段经历了先增强后减弱的动态变化,提示脑血流低灌注老龄大鼠因大脑血流灌注不足可出现体内胆固醇代谢失衡并出现应激调节现象.%Objective: To investigate the change of cortical blood flow and the dynamic changes of serum total cholesterol(TC ) and high density lipoprotein(HDL) in brains of aging rat during cerebral ischemic injury. Methods:The model of aging rats with cerebral hy-poperfusion was successfully constructed by persistent bilateral common carotid artery ligation(2V0). The cortical blood flow and the concentration of serum TC and HDL at different time points were determined and compared. Results: Compared with the sham-operated group,the temporal blood flow was significantly decreased in 14 d group. But the collateral vessels were gradually regenerated and formed in local brain,while the temporal blood flow was restored in 21 d and 28 d group. The concentration of HDL and TC was significantly higher in 14 d group than in the sham-operated group (P<0.05), and both of them were decreased with the extention of ischemia time. Conclusions:The serum TC and HDL concentration undergo dynamic changes-increasing first and then decreasing during the process

  10. Magnetic resonance perfusion imaging evaluation in perfusion abnormalities of the cerebellum after supratentorial unilateral hyperacute cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Pan Liang; Yunjun Yang; Weijian Chen; Yuxia Duan; Hongqing Wang; Xiaotong Wang

    2012-01-01

    Magnetic resonance imaging (MRI) data of 10 patients with hyperacute cerebral infarction (≤ 6 hours) were retrospectively analyzed. Six patients exhibited perfusion defects on negative enhancement integral maps, four patients exhibited perfusion differences in pseudo-color on mean time to enhance maps, and three patients exhibited perfusion differences in pseudo-color on time to minimum maps. Dynamic susceptibility contrast-enhanced perfusion weighted imaging revealed a significant increase in region negative enhancement integral in the affected hemisphere of patients with cerebral infarction. The results suggest that dynamic susceptibility contrast-enhanced perfusion weighted imaging can clearly detect perfusion abnormalities in the cerebellum after unilateral hyperacute cerebral infarction.

  11. What You Should Know about Cerebral Aneurysms

    Science.gov (United States)

    ... T. Quiz 5 Things to Know About Stroke What You Should Know About Cerebral Aneurysms Updated:Jun ... Damage Treatments Click image to view an animation What is a cerebral aneurysm? An aneurysm is a ...

  12. Middle cerebral artery blood velocity during rowing

    DEFF Research Database (Denmark)

    Secher, Niels Henry; Pott, F; Knudsen, L.;

    1997-01-01

    original,arterial blood pressure,central venous pressure,cerebral blood flow, exercise, transcranial Doppler......original,arterial blood pressure,central venous pressure,cerebral blood flow, exercise, transcranial Doppler...

  13. Primary cerebral lymphoma

    International Nuclear Information System (INIS)

    The aim of this study is to compare the survival of the patients treated with radiotherapy alone vs. patients treated with a combined schedule of radio-chemotherapy. Our results will be compared with currently published data and main prognostic factors will be briefly discussed. Patients and methods: Between 1974 and 1990, 27 cases of primary cerebral lymphoma were diagnosed at our institution. All patients had biopsy-proven disease, the pathology of which was reviewed for this study. Results: The overall median survival time was 24 months and one-, two- and three-year overall survival was 59, 46 and 29% respectively. The median radiation dose was 46 Gy, ranging from 19.5 to 60 Gy. The median dose per fraction was 2 Gy (ranging from 1.61 to 3 Gy). The median elapsed treatment time was 32 days (ranging from three to 45 days). We were not able to demonstrate any statistically significant difference between patients who received radiotherapy alone (n = 14, median survival time = 24 months) and those who received a combination of chemotherapy and radiotherapy (n = 11, median survival time = 30 months), (p = 0.4). Prognostic factors of survival were tested using a univariate analysis (Wilcoxon test). Parameters such as mass appearance (unilobular, p = 0.048), performance status at the time of the diagnosis (0 to 1, p = 0.014), and CT imaging (hypodense, p = 0.043) influenced positively survival. Centroblastic histology (Kiel) was found associated with a negative prognosis (p = 0.043). (orig./MG)

  14. Cerebritis: an unusual complication of Klebsiella pneumoniae.

    Science.gov (United States)

    Majumdar, Mainak; Simes, David C; Prabha, Ramesh D

    2009-01-01

    Cerebritis is part of a continuum of brain infection and is difficult to diagnose. Cerebritis caused by Klebsiella in immunocompetent adults without predisposing factors such as neurosurgery or penetrating brain injury has not been reported before. We report a case of Klebsiella cerebritis in an adult patient with a proven extracranial focus of infection. We suggest considering cerebritis as a differential diagnosis for altered level of consciousness in patients of severe sepsis, even if an extracranial source of infection is proven. PMID:19881180

  15. Cerebritis: An unusual complication of Klebsiella pneumoniae

    OpenAIRE

    Majumdar, Mainak; Simes1, David C.; Prabha1, Ramesh D.

    2009-01-01

    Cerebritis is part of a continuum of brain infection and is difficult to diagnose. Cerebritis caused by Klebsiella in immunocompetent adults without predisposing factors such as neurosurgery or penetrating brain injury has not been reported before. We report a case of Klebsiella cerebritis in an adult patient with a proven extracranial focus of infection. We suggest considering cerebritis as a differential diagnosis for altered level of consciousness in patients of severe sepsis, even if an e...

  16. Cerebritis: An unusual complication of Klebsiella pneumoniae

    Science.gov (United States)

    Majumdar, Mainak; Simes1, David C.; Prabha1, Ramesh D.

    2009-01-01

    Cerebritis is part of a continuum of brain infection and is difficult to diagnose. Cerebritis caused by Klebsiella in immunocompetent adults without predisposing factors such as neurosurgery or penetrating brain injury has not been reported before. We report a case of Klebsiella cerebritis in an adult patient with a proven extracranial focus of infection. We suggest considering cerebritis as a differential diagnosis for altered level of consciousness in patients of severe sepsis, even if an extracranial source of infection is proven. PMID:19881180

  17. Cerebral edema associated with acute hepatic failure.

    OpenAIRE

    Fujiwara, Masachika; Watanabe,Akiharu; Yamauchi,Yasuhiko; Hashimoto, Makoto; Nakatsukasa, Harushige; Kobayashi, Michio; Higashi,Toshihiro; Nagashima,Hideo

    1985-01-01

    The clinicopathological findings of cerebral edema were investigated in patients with acute hepatic failure autopsied at Okayama University Hospital between 1970 and 1980 retrospectively. Nine (64%) of 14 hepatic failure cases were found to have cerebral edema during a post-mortem examination of the brain. Clinical features of the patients with cerebral edema were not significantly different from those of the patients without cerebral edema. However, general convulsions were observed more fre...

  18. Neuronal autophagy in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Jin-Hua Gu; Zheng-Hong Qin

    2012-01-01

    Autophagy has evolved as a conserved process for the bulk degradation and recycling of cytosolic components,such as long-lived proteins and organelles.In neurons,autophagy is important for homeostasis and protein quality control and is maintained at relatively low levels under normal conditions,while it is upregulated in response to pathophysiological conditions,such as cerebral ischemic injury.However,the role of autophagy is more complex.It depends on age or brain maturity,region,severity of insult,and the stage of ischemia.Whether autophagy plays a beneficial or a detrimental role in cerebral ischemia depends on various pathological conditions.In this review,we elucidate the role of neuronal autophagy in cerebral ischemia.

  19. Reduced accommodation in children with cerebral palsy.

    Science.gov (United States)

    Leat, S J

    1996-09-01

    Accommodation in 43 subjects with cerebral palsy was measured objectively using a dynamic retinoscopy technique, which has already been shown to be reliable and repeatable. The subject's ages ranged from 3 to 35 years. Of these, 42% were found to have an accommodative response pattern which was different from the normal control group for his/her age. Nearly 29% had an estimated amplitude of accommodation of 4 D or less. The presence of reduced accommodation was found to be associated with reduced visual acuity, but was not associated with cognitive or communication ability, refractive error or age. The prevalence of other ocular disorders in this group is also high. These findings have developmental and educational implications.

  20. Vascular permeability in cerebral cavernous malformations

    DEFF Research Database (Denmark)

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao;

    2015-01-01

    -controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability...... vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy.......Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case...

  1. Cerebral state index during propofol anesthesia

    NARCIS (Netherlands)

    Jensen, EW; Litvan, H; Revuelta, M; Rodriguez, BE; Caminal, P; Martinez, P; Vereecke, H; Struys, MMRF

    2006-01-01

    Background: The objective of this study was to prospectively test the Cerebral State Index designed for measuring the depth of anesthesia. The Cerebral State Index is calculated using a fuzzy logic combination of four subparameters of the electroencephalographic signal. The performance of the Cerebr

  2. Cerebral toksoplasmose primaert diagnosticeret som tumor

    DEFF Research Database (Denmark)

    Cortsen, M E; Skøt, J; Skriver, E B

    1992-01-01

    Three cases of cerebral toxoplasmosis as the presenting manifestation of AIDS are reported. The initial diagnoses were brain tumors because of the cerebral mass lesions which resembled glioblastoma. In the light of the increasing occurrence of AIDS, attention is drawn to cerebral toxoplasmosis...

  3. Neuroevolutional Approach to Cerebral Palsy and Speech.

    Science.gov (United States)

    Mysak, Edward D.

    Intended for cerebral palsy specialists, the book emphasizes the contribution that a neuroevolutional approach to therapy can make to habilitation goals of the child with cerebral palsy and applies the basic principles of the Bobath approach to therapy. The first section discusses cerebral palsy as a reflection of disturbed neuro-ontogenisis and…

  4. Cerebral vasculitis associated with cocaine abuse

    International Nuclear Information System (INIS)

    A case of cerebral vasculitis in a previously healthy 22-year-old man with a history of cocaine abuse is described. Cerebral angiograms showed evidence of vasculitis. A search for possible causes other than cocaine produced no results. The authors include cocaine with methamphetamines, heroin, and ephedrine as illicit drugs that can cause cerebral vasculitis

  5. A comparison of measurements of cerebral blood flow in the rabbit using laser Doppler spectroscopy and radionuclide labelled microspheres.

    Science.gov (United States)

    Eyre, J A; Essex, T J; Flecknell, P A; Bartholomew, P H; Sinclair, J I

    1988-02-01

    Laser Doppler spectroscopy has been evaluated for the measurement of cerebral blood flow (CBF) by correlation with simultaneous measurements by radionuclide labelled microspheres. The experimental procedures were carried out on five anaesthetised rabbits. The cortical tissue was exposed by means of a small burr hole and illuminated by a helium neon laser (632.8 nm). Reflected light was detected using a silicon photodiode, and CBF was calculated continuously from the power of the frequency weighted Doppler spectrum in the reflected light. Three successive measurements of CBF were made using the microsphere technique. Following an initial baseline measurement, CBF was increased by an infusion of metaraminol and then reduced by controlled haemorrhage. Laser Doppler spectroscopy provided continuous monitoring of blood flow fluctuations and during the haemorrhage it was possible to demonstrate CBF autoregulation until the mean blood pressure fell below 6.7 kPa (50 mmHg). A regression analysis was performed between the simultaneous CBF measurements from the two techniques using a least squares best fit straight line analysis (r = 0.92, P less than 0.001). It was concluded that the flow computed from laser Doppler spectroscopy varied linearly with CBF and offers the unique advantage of continuous and instantaneous measurements even during nonsteady state flow.

  6. Features to validate cerebral toxoplasmosis

    Directory of Open Access Journals (Sweden)

    Carolina da Cunha Correia

    2013-06-01

    Full Text Available Introduction Neurotoxoplasmosis (NT sometimes manifests unusual characteristics. Methods We analyzed 85 patients with NT and AIDS according to clinical, cerebrospinal fluid, cranial magnetic resonance, and polymerase chain reaction (PCR characteristics. Results In 8.5%, focal neurological deficits were absent and 16.4% had single cerebral lesions. Increased sensitivity of PCR for Toxoplasma gondii DNA in the central nervous system was associated with pleocytosis and presence of >4 encephalic lesions. Conclusions Patients with NT may present without focal neurological deficit and NT may occur with presence of a single cerebral lesion. Greater numbers of lesions and greater cellularity in cerebrospinal fluid improve the sensitivity of PCR to T gondii.

  7. Lifetime costs of cerebral palsy

    DEFF Research Database (Denmark)

    Kruse, Marie; Michelsen, Susan Ishøy; Flachs, Esben Meulengracht;

    2009-01-01

    This study quantified the lifetime costs of cerebral palsy (CP) in a register-based setting. It was the first study outside the US to assess the lifetime costs of CP. The lifetime costs attributable to CP were divided into three categories: health care costs, productivity costs, and social costs....... The population analyzed was retrieved from the Danish Cerebral Palsy Register, which covers the eastern part of the country and has registered about half of the Danish population of individuals with CP since 1950. For this study we analyzed 2367 individuals with CP, who were born in 1930 to 2000 and were alive...

  8. Effects of hyperglycemia on the cerebrovascular response to rhythmic handgrip exercise

    NARCIS (Netherlands)

    Y.S. Kim; R. Krogh-Madsen; P. Rasmussen; P. Plomgaard; S. Ogoh; N.H. Secher; J.J. van Lieshout

    2007-01-01

    Dynamic cerebral autoregulation (CA) is challenged by exercise and may become less effective when exercise is exhaustive. Exercise may increase arterial glucose concentration, and we evaluated whether the cerebrovascular response to exercise is affected by hyperglycemia. The effects of a hyperinsuli

  9. Contraceptives and cerebral thrombosis: a five-year national case-control study

    DEFF Research Database (Denmark)

    Lidegaard, Øjvind; Kreiner, Svend

    2002-01-01

    Oral contraceptives; Cerebral thrombosis; Thrombotic stroke; Transitory cerebral ischemic attack; Thrombosis......Oral contraceptives; Cerebral thrombosis; Thrombotic stroke; Transitory cerebral ischemic attack; Thrombosis...

  10. Early cerebral circulatory disturbance in patients suffering subarachnoid hemorrhage prior to the delayed cerebral vasospasm stage. Xenon computed tomography and perfusion computed tomography study

    International Nuclear Information System (INIS)

    Subarachnoid hemorrhage (SAH) causes dynamic changes in cerebral blood flow (CBF), and results in delayed ischemia due to vasospasm, and early perfusion deficits before delayed cerebral vasospasm (CVS). The present study examined the severity of cerebral circulatory disturbance during the early phase before delayed CVS and whether it can be used to predict patient outcome. A total of 94 patients with SAH underwent simultaneous xenon computed tomography (CT) and perfusion CT to evaluate cerebral circulation on Days 1-3. Cerebral blood flow (CBF) was measured using xenon CT and the mean transit time (MTT) using perfusion CT and calculated cerebral blood volume (CBV). Outcome was evaluated with the Glasgow Outcome Scale (good recovery [GR], moderate disability [MD], severe disability [SD], vegetative state [VS], or death [D]). Hunt and Hess (HH) grade II patients displayed significantly higher CBF and lower MTT than HH grade IV and V patients. HH grade III patients displayed significantly higher CBF and lower MTT than HH grade IV and V patients. Patients with favorable outcome (GR or MD) had significantly higher CBF and lower MTT than those with unfavorable outcome (SD, VS, or D). Discriminant analysis of these parameters could predict patient outcome with a probability of 74.5%. Higher HH grade on admission was associated with decreased CBF and CBV and prolonged MTT. CBF reduction and MTT prolongation before the onset of delayed CVS might influence the clinical outcome of SAH. These parameters are helpful for evaluating the severity of SAH and predicting the outcomes of SAH patients. (author)

  11. Caffeine induced changes in cerebral circulation

    International Nuclear Information System (INIS)

    While the caffeine induced cerebral vasoconstriction is well documented, the effects of oral ingestion of the drug in a dose range comparable to the quantities in which it is usually consumed and the intensity and duration of the associated reduction in cerebral circulation are unknown. Cerebral blood flow was measured via the 133Xenon inhalation technique before and thirty and ninety minutes after the oral administration of 250 mg of caffeine or a placebo, under double-blind conditions. Caffeine ingestion was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later. The placebo group showed no differences between the three sets of cerebral blood flow values

  12. MYC acts via the PTEN tumor suppressor to elicit autoregulation and genome-wide gene repression by activation of the Ezh2 methyltransferase

    Science.gov (United States)

    Kaur, Mandeep; Cole, Michael D.

    2012-01-01

    The control of normal cell growth is a balance between stimulatory and inhibitory signals. MYC is a pleiotropic transcription factor that both activates and represses a broad range of target genes and is indispensable for cell growth. While much is known about gene activation by MYC, there is no established mechanism for the majority of MYC repressed genes. We report that MYC transcriptionally activates the PTEN tumor suppressor in normal cells to inactivate the PI3K pathway, thus suppressing AKT activation. Suppression of AKT enhances the activity of the EZH2 histone methyltransferase, a subunit of the epigenetic repressor Polycomb Repressive Complex 2 (PRC2), while simultaneously stabilizing the protein. MYC mediated enhancement in EZH2 protein level and activity results in local and genome-wide elevation in the repressive H3K27me3 histone modification, leading to widespread gene repression including feedback autoregulation of the MYC gene itself. Depletion of either PTEN or EZH2 and inhibition of the PI3K/AKT pathway leads to gene derepression. Importantly, expression of a phospho-defective EZH2 mutant is sufficient to recapitulate nearly half of all MYC-mediated gene repression. We present a novel epigenetic model for MYC-mediated gene repression and propose that PTEN and MYC exist in homeostatic balance to control normal growth which is disrupted in cancer cells. PMID:23135913

  13. Changes in the profile of NO synthases affect coronary blood flow autoregulation and myocardial contractile activity during restraint stress in rats.

    Science.gov (United States)

    Solodkov, A P; Lazuko, S S; Knyazev, E N; Nechaev, I N; Krainova, N A

    2014-12-01

    The efficiency of autoregulation of the coronary blood flow and contractile activity of the myocardium in the presence of inhibitors of constitutive and inducible NO synthases was studied in rats exposed to 6-h restraint stress. Intracoronary administration of S-methylisothiourea (10 μmol/liter), but not L-NAME (60 μmol/liter) fully prevented post-stress increase in the volume coronary blood flow rate, intensity of heart perfusion, and reduction of ventricular developed pressure at all levels of perfusion pressure. Real-time PCR showed 6-fold increased expression of inducible NO-synthase mRNA in the heart tissue against the background of unchanged expression of neuronal and endothelial NO synthases and 2-3-fold elevated content of transcripts of stress-inducible genes Hspa1a and Hspbp1. It was shown that the hypotension of coronary vessels and reduced contractile function of the myocardium are related to NO production by inducible NO synthase in endotheliocytes of coronary vessels and cardiomyocytes. PMID:25430647

  14. Genomic analysis suggests that mRNA destabilization by the microprocessor is specialized for the auto-regulation of Dgcr8.

    Directory of Open Access Journals (Sweden)

    Archana Shenoy

    Full Text Available BACKGROUND: The Microprocessor, containing the RNA binding protein Dgcr8 and RNase III enzyme Drosha, is responsible for processing primary microRNAs to precursor microRNAs. The Microprocessor regulates its own levels by cleaving hairpins in the 5'UTR and coding region of the Dgcr8 mRNA, thereby destabilizing the mature transcript. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether the Microprocessor has a broader role in directly regulating other coding mRNA levels, we integrated results from expression profiling and ultra high-throughput deep sequencing of small RNAs. Expression analysis of mRNAs in wild-type, Dgcr8 knockout, and Dicer knockout mouse embryonic stem (ES cells uncovered mRNAs that were specifically upregulated in the Dgcr8 null background. A number of these transcripts had evolutionarily conserved predicted hairpin targets for the Microprocessor. However, analysis of deep sequencing data of 18 to 200nt small RNAs in mouse ES, HeLa, and HepG2 indicates that exonic sequence reads that map in a pattern consistent with Microprocessor activity are unique to Dgcr8. CONCLUSION/SIGNIFICANCE: We conclude that the Microprocessor's role in directly destabilizing coding mRNAs is likely specifically targeted to Dgcr8 itself, suggesting a specialized cellular mechanism for gene auto-regulation.

  15. Variables that affect the middle cerebral artery peak systolic velocity in fetuses with anemia and intrauterine growth restriction.

    Science.gov (United States)

    Hanif, Farhan; Drennan, Kathrin; Mari, Giancarlo

    2007-09-01

    We have previously reported that the fetal middle cerebral artery (MCA) peak systolic velocity (PSV) increases in anemic fetuses and in fetuses with intrauterine growth restriction (IUGR). We hypothesized that the pathophysiology for the increased MCA PSV is different in anemic and IUGR fetuses. Thus the aim of this study was to determine the factor(s) among fetal umbilical vein blood pH, Po2, Pco2, and hemoglobin that might affect the MCA PSV in fetuses with anemia and IUGR. This study included two groups of fetuses. The first group included fetuses at risk for anemia because of red cell alloimmunization, whereas the second group included IUGR fetuses. For both groups of fetuses, we determined hemoglobin, umbilical vein blood gases -- at cordocentesis in anemic fetuses and immediately after cesarean delivery in IUGR fetuses -- and MCA PSV before cordocentesis, or before delivery. The relationship between MCA PSV and the hemoglobin, Po2, Pco2, and pH values for the anemic and the IUGR fetuses were assessed by regression analysis using multiples of the mean. There were 14 fetuses in the first group and 22 fetuses in the second group. In the first group, the only parameter that was related to MCA PSV was the fetal hemoglobin (R2 = 0.34; p < 0.05); in fetuses with IUGR, the Pco2 (R2 = 0.36; p < 0.01) and the PO2 (R2 = 0.30; p < 0.01) correlated well with the MCA PSV, whereas no relationship was found between the MCA PSV and the hemoglobin. The data indicate that the mechanism of high MCA PSV is different in anemic and nonanemic IUGR fetuses, and suggest that the process of cerebral autoregulation is present in the preterm IUGR fetus.

  16. Embodying Investigations of Cerebral Palsy

    DEFF Research Database (Denmark)

    Martiny, Kristian Møller Moltke

    The main question of Kristian Martiny’s dissertation is: how do we help persons living with the brain damage, cerebral palsy (CP)? This question is as complex and difficult to answer as any healthcare question. Martiny argues that we need to ‘open up’ how we do ( cognitive ) science in order...

  17. MR imaging of cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Saginoya, Toshiyuki [Urasoe General Hospital, Okinawa (Japan); Yamaguchi, Keiichiro; Kuniyoshi, Kazuhide [and others

    1996-06-01

    We evaluated 35 patients with cerebral palsy on the basis of MR imaging findings in the brain. The types of palsy were spastic quadriplegia (n=11), spastic diplegia (n=9), spastic hemiplegia (n=2), double hemiplegia (n=1), athetosis (n=10) and mixed (n=2). Of all patients, 28 (80%) generated abnormal findings. In spastic quadriplegia, although eight cases revealed severe brain damage, two cases showed no abnormal findings in the brain. One of the three had cervical cord compression caused by atlanto-axial subluxation. In spastic diplegia, the findings were divided according to whether the patient was born at term or preterm. If the patient had been born prematurely, the findings showed periventricular leukomalacia and abnormally high intensity in the posterior limbs of the internal capsule on T2-weighted images. MR imaging in spastic hemiplegia revealed cerebral infarction. In the athetoid type, half of all cases showed either no abnormal findings or slight widening of the lateral ventricle. Three cases showed abnormal signals of the basal ganglia. The reason why athetoid-type palsy did not show severe abnormality is unknown. We believe that MR imaging is a useful diagnostic modality to detect damage in the brain in cerebral palsy and plays an important role in the differentiation of cerebral palsy from the spastic palsy disease. (author)

  18. Cerebral blood-flow tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Holm, S;

    1983-01-01

    Tomographic maps of local cerebral blood flow (CBF) were obtained with xenon-133 and with isopropyl-amphetamine-iodine-123 (IMP) in 11 subjects: one normal, two tumor cases, and eight cerebrovascular cases. A highly sensitive four-face, rapidly rotating, single-photon emission tomograph was used...

  19. Cerebral imaging revealing Alzheimer's disease

    International Nuclear Information System (INIS)

    Cerebral imaging is the only non-invasive means of examining the brain and is essential in studying Alzheimer's disease. As a tool for early diagnosis, evaluation and treatment monitoring, this technology is at the heart of the research being done to further improve its reliability and sensitivity. (authors)

  20. MR imaging of cerebral palsy

    International Nuclear Information System (INIS)

    We evaluated 35 patients with cerebral palsy on the basis of MR imaging findings in the brain. The types of palsy were spastic quadriplegia (n=11), spastic diplegia (n=9), spastic hemiplegia (n=2), double hemiplegia (n=1), athetosis (n=10) and mixed (n=2). Of all patients, 28 (80%) generated abnormal findings. In spastic quadriplegia, although eight cases revealed severe brain damage, two cases showed no abnormal findings in the brain. One of the three had cervical cord compression caused by atlanto-axial subluxation. In spastic diplegia, the findings were divided according to whether the patient was born at term or preterm. If the patient had been born prematurely, the findings showed periventricular leukomalacia and abnormally high intensity in the posterior limbs of the internal capsule on T2-weighted images. MR imaging in spastic hemiplegia revealed cerebral infarction. In the athetoid type, half of all cases showed either no abnormal findings or slight widening of the lateral ventricle. Three cases showed abnormal signals of the basal ganglia. The reason why athetoid-type palsy did not show severe abnormality is unknown. We believe that MR imaging is a useful diagnostic modality to detect damage in the brain in cerebral palsy and plays an important role in the differentiation of cerebral palsy from the spastic palsy disease. (author)

  1. Cerebral edema in drug addicts

    Directory of Open Access Journals (Sweden)

    Daruši Dragana J.

    2014-01-01

    Full Text Available Background/Aim. The effect of drugs leaves permanent consequences on the brain, organic in type, followed by numerous manifestations, and it significantly affects the development of mental dysfunctions. The clinicians are often given a task to estimate a patient’s personality during treatment or during experts estimate of a drug addict. The aim of this research was to determine the differences, if any, in characteristics of addicts experience and personality traits in drug addicts with or without cerebral edema. Methods. The research was conducted on a sample of 252 male drug addicts, the average age of 23.3 (SD = 4.3 years. Cerebral edema was confirmed on magnetic resonance (MR images of the brain performed during the treatment of the addicts. The participants were tested by the psychologists using Minnesota Multiphasic Personality Inventory (MMPI-201 test, and the data were processed using canonical discriminate analysis within the SPSS program. The dependent variable in the study was cerebral edema. A block of independent variables, designed for the requirements of this study, consisted of two subgroups. The first one consisted of 12 variables describing the relevant characteristics of drug abuse. The second subgroup consisted of 8 psychopathological tendencies in the personality defined by the mentioned test. Results. Cerebral edema was confirmed in 52 (20.63% of the drug addicts. The differences between the groups of drug addicts with and without cerebral edema were determined in the following: the time span of taking drugs (0.301, use of alcohol parallel with drugs (0.466, and treatment for addiction (0.603. In the drug addicts with a cerebral edema, MMPI-201 confirmed the increase in the scales for hypochondria, psychopathic deviations and psychastenia, and the decrease in the scales for schizophrenia and depression. Conclusion. Our study confirmed a possible connection between cerebral edema and personality traits in a number of the

  2. Anestesia e paralisia cerebral Anestesia y parálisis cerebral Anesthesia and cerebral palsy

    Directory of Open Access Journals (Sweden)

    Március Vinícius M Maranhão

    2005-12-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: A paralisia cerebral (PC é uma doença não progressiva decorrente de lesão no sistema nervoso central, levando a um comprometimento motor do paciente. O portador de PC freqüentemente é submetido a procedimentos cirúrgicos devido a doenças usuais e situações particulares decorrentes da paralisia cerebral. Foi objetivo deste artigo revisar aspectos da paralisia cerebral de interesse para o anestesiologista, permitindo um adequado manuseio pré, intra e pós-operatório neste tipo de paciente. CONTEÚDO: O artigo aborda aspectos da paralisia cerebral como etiologia, classificação, fatores de risco, fisiopatologia, quadro clínico, diagnóstico, terapêuticas utilizadas bem como avaliação pré-operatória, medicação pré-anestésica, manuseio intra e pós-operatório, analgesia pós-operatória e dor crônica. CONCLUSÕES: O anestesiologista desempenha um papel importante na diminuição da morbidade e mortalidade anestésico-cirúrgica em pacientes portadores de paralisia cerebral. O conhecimento da fisiopatologia dos diferentes tipos de paralisia cerebral bem como das doenças associadas e suas terapêuticas é imprescindível, pois permite ao anestesiologista antecipar e prevenir complicações intra e pós-operatórias neste tipo de paciente.JUSTIFICATIVA Y OBJETIVOS: La parálisis cerebral (PC es una enfermedad no progresiva consecuente de una lesión en el sistema nervioso central, llevando a un comprometimiento motor del paciente. El portador de PC, frecuentemente es sometido a procedimientos quirúrgicos debido a enfermedades usuales y situaciones particulares consecuentes de la parálisis cerebral. El objetivo de este artículo, fue revisar aspectos de la parálisis cerebral de interés para el anestesista, permitiendo un adecuado manoseo pre, intra y posoperatorio en este tipo de paciente. CONTENIDO: El artículo aborda aspectos de la parálisis cerebral como etiología, clasificación, factores de

  3. The effects of propofol on cerebral perfusion MRI in children

    Energy Technology Data Exchange (ETDEWEB)

    Harreld, Julie H.; Helton, Kathleen J.; Reddick, Wilburn E.; Glass, John O.; Sansgiri, Rakhee; Ji, Qing; Patay, Zoltan [St. Jude Children' s Research Hospital, Department of Radiological Sciences, Memphis, TN (United States); Kaddoum, Roland N.; Parish, Mary Edna [St. Jude Children' s Research Hospital, Department of Anesthesiology, Memphis, TN (United States); Li, Yimei; Feng, Tianshu [St. Jude Children' s Research Hospital, Department of Biostatistics, Memphis, TN (United States); Gajjar, Amar [St. Jude Children' s Research Hospital, Department of Oncology, Memphis, TN (United States)

    2013-08-15

    The effects of anesthesia are infrequently considered when interpreting pediatric perfusion magnetic resonance imaging (MRI). The objectives of this study were to test for measurable differences in MR measures of cerebral blood flow (CBF) and cerebral blood volume (CBV) between non-sedated and propofol-sedated children, and to identify influential factors. Supratentorial cortical CBF and CBV measured by dynamic susceptibility contrast perfusion MRI in 37 children (1.8-18 years) treated for infratentorial brain tumors receiving propofol (IV, n = 19) or no sedation (NS, n = 18) were compared between groups and correlated with age, hematocrit (Hct), end-tidal CO{sub 2} (ETCO{sub 2}), dose, weight, and history of radiation therapy (RT). The model most predictive of CBF and CBV was identified by multiple linear regression. Anterior cerebral artery (ACA) and middle cerebral artery (MCA) territory CBF were significantly lower, and MCA territory CBV greater (p = 0.03), in IV than NS patients (p = 0.01, 0.04). The usual trend of decreasing CBF with age was reversed with propofol in ACA and MCA territories (r = 0.53, r = 0.47; p < 0.05). ACA and MCA CBF (r = 0.59, 0.49; p < 0.05) and CBV in ACA, MCA, and posterior cerebral artery territories (r = 0.73, 0.80, 0.52; p < 0.05) increased with weight in propofol-sedated children, with no significant additional influence from age, ETCO{sub 2}, hematocrit, or RT. In propofol-sedated children, usual age-related decreases in CBF were reversed, and increases in CBF and CBV were weight-dependent, not previously described. Weight-dependent increases in propofol clearance may diminish suppression of CBF and CBV. Prospective study is required to establish anesthetic-specific models of CBF and CBV in children. (orig.)

  4. Regional cerebral blood flow after hemorrhagic hypotension in the preterm, near-term, and newborn lamb.

    Science.gov (United States)

    Szymonowicz, W; Walker, A M; Yu, V Y; Stewart, M L; Cannata, J; Cussen, L

    1990-10-01

    Developmental changes in regional cerebral blood flow (CBF) responses to hemorrhagic hypotension during normoxia and normocapnia were determined using radioactively labeled microspheres to measure flow to the cortex, brainstem, cerebellum, white matter, caudate nucleus, and choroid plexus in three groups of chronically catheterized lambs: 90- to 100-d preterm fetal lambs (n = 9); 125- to 136-d near-term fetal lambs (n = 9); and newborn lambs 5- to 35-d-old (n = 8). Heart rate, central venous pressure, and arterial blood pressure were monitored continuously and arterial blood gas tensions, pH, Hb, and oxygen saturation together with regional CBF were measured periodically. Hemorrhagic hypotension produced a mean decrease in arterial blood pressure of 27 +/- 4, 23 +/- 2, and 41 +/- 4% in the three groups, respectively, whereas reinfusion of the lamb's blood resulted in a return to control blood pressure within 3% in all three groups. In the pre-term fetal lamb, CBF decreased significantly in all regions during hypotension. In the near-term fetal lamb, only blood flow to the cortex decreased significantly during hypotension. In the newborn lamb, only the choroid plexus demonstrated a significant decrease in blood flow during hypotension. The lower limit of regional CBF autoregulation was identical to the resting mean arterial pressure in fetal life but significantly lower in newborn lambs. These experiments demonstrate for the first time that vulnerability to hypotension decreases with increasing maturity and that the brainstem, the phylogenetically oldest region of the brain, is the least vulnerable to the effects of hypotension at any age in the lamb model. PMID:2235134

  5. A model for cerebral ischaemia from gaseous emboli

    CERN Document Server

    Hague, J P; Chung, E M L

    2012-01-01

    The effects of bubbles on the cerebral bloodflow are difficult to quantify. We present a model to calculate how cerebral ischaemia is caused by deformable gaseous emboli. The model takes into account realistic adhesion forces, fluid dynamical considerations, a realistic parameterisaton for the rate of bubble dissolution and the effects of buoyancy. We find that neglecting deformability of bubbles leads to a vast overestimation of ischaemia. The inclusion of buoyancy effects reduces the proportion of the vasculature that becomes compromised, but increases blockage times, thus lowering the risk of transient ischaemia but increasing the potential for focal injury. We also investigate the number and size of bubbles in a sudden shower of emboli that leads to persistent ischaemia capable of neuronal injury. Finally we investigate mitigation techniques such as insufflation of the operative area with CO$_2$ and alterations in arterial pressure.

  6. Cerebral aterial spasm. I. Adrenergic mechanism in experimental cerebral vasospasm.

    Directory of Open Access Journals (Sweden)

    Morooka,Hiroshi

    1978-04-01

    Full Text Available This study demonstrates that an adrenergic mechanism plays an important role in producing the delayed cerebral vasospasm which follows subarachnoid hemorrhage. Results were as follows: 1. Experimental subarachnoid hemorrhage (SAH was produced by injection of fresh arterial blood into the cisterna magna in cats. The cerebral vasospasm was shown angiographically to be biphasic in nature: immediate constriction lasting 1 h and marked prolonged spasm occurring between the 3rd and 5th day after SAH. The amount of noradrenaline (NA and dopamine-beta-hydroxylase (DBH activity decreased over a period of 24 h both within the wall of the basilar artery and in the locus ceruleus and then gradually increased, reaching a maximum on the 3rd day after SAH. 2. Topical application of spasmogenic substances (NA and blood produced a marked constriction of the hypersensitive basilar artery on the 3rd day after SAH. 3. 6-Hydroxydopamine (6-OHDA injection into the cisterna magna produced prolonged vasocilatation. The dilated vessel responded with mild transient constriction after the topical application of NA or fresh blood. DBH activity and NA concentration in the vessels, locus ceruleus and medial hypothalamus decreased markedly on the 3rd day after the cisternal injection of 6-OHDA. 4. Various spasmogenic substances (i.e. serotonin, NA, prostaglandins and methemoglobin were measured in a mixture of equal volume of CSF and blood in cats. ONly the serotonin in the mixed fluid produced vasoconstriction. Spasmogenic substances decreased markedly in the mixed fluid incubated for 3 days at 37 degrees C, and none of these substances apart from methemoglobin was present in a concentration sufficient to produce constriction of vessels. 5. These results suggest that early spasm is induced by serotonin around the arteries of the cranial base, and delayed spasm might be caused by hyperreaction of cerebral vessels to spasmogenic substances such as methemoglobin, during the

  7. Time evolution and hemodynamics of cerebral aneurysms

    Science.gov (United States)

    Sforza, Daniel M.; Putman, Christopher; Tateshima, Satoshi; Viñuela, Fernando; Cebral, Juan

    2011-03-01

    Cerebral aneurysm rupture is a leading cause of hemorrhagic strokes. Because they are being more frequently diagnosed before rupture and the prognosis of subarachnoid hemorrhage is poor, clinicians are often required to judge which aneurysms are prone to progression and rupture. Unfortunately, the processes of aneurysm initiation, growth and rupture are not well understood. Multiple factors associated to these processes have been identified. Our goal is to investigate two of them, arterial hemodynamics (using computational fluid dynamics) and the peri-aneurysmal environment, by studying a group of growing cerebral aneurysms that are followed longitudinally in time. Six patients with unruptured untreated brain aneurysms which exhibited growth during the observation period were selected for the study. Vascular models of each aneurysm at each observation time were constructed from the corresponding computed tomography angiography (CTA) images. Subsequently, models were aligned, and geometrical differences quantified. Blood flow was modeled with the 3D unsteady incompressible Navier-Stokes equation for a Newtonian fluid, and wall shear stress distribution and flow patterns were calculated and visualized. Analysis of the simulations and changes in geometry revealed asymmetric growth patterns and suggests that areas subject to vigorous flows, i.e. relative high wall shear stress and concentrated streamlines patterns; correspond to regions of aneurysm growth. Furthermore, in some cases the geometrical evolution of aneurysms is clearly affected by contacts with bone structures and calcifications in the wall, and as a consequence the hemodynamics is greatly modified. Thus, in these cases the peri-aneurysmal environment must be considered when analyzing aneurysm evolution.

  8. Chinese semantic processing cerebral areas

    Institute of Scientific and Technical Information of China (English)

    SHAN Baoci; ZHANG Wutian; MA Lin; LI Dejun; CAO Bingli; TANG Yiyuan; WU Yigen; TANG Xiaowei

    2003-01-01

    This study has identified the active cerebral areas of normal Chinese that are associated with Chinese semantic processing using functional brain imaging. According to the traditional cognitive theory, semantic processing is not particularly associated with or affected by input modality. The functional brain imaging experiments were conducted to identify the common active areas of two modalities when subjects perform Chinese semantic tasks through reading and listening respectively. The result has shown that the common active areas include left inferior frontal gyrus (BA 44/45), left posterior inferior temporal gyrus (BA37); the joint area of inferior parietal lobules (BA40) and superior temporal gyrus, the ventral occipital areas and cerebella of both hemispheres. It gives important clue to further discerning the roles of different cerebral areas in Chinese semantic processing.

  9. Animal models of cerebral ischemia

    Science.gov (United States)

    Khodanovich, M. Yu.; Kisel, A. A.

    2015-11-01

    Cerebral ischemia remains one of the most frequent causes of death and disability worldwide. Animal models are necessary to understand complex molecular mechanisms of brain damage as well as for the development of new therapies for stroke. This review considers a certain range of animal models of cerebral ischemia, including several types of focal and global ischemia. Since animal models vary in specificity for the human disease which they reproduce, the complexity of surgery, infarct size, reliability of reproduction for statistical analysis, and adequate models need to be chosen according to the aim of a study. The reproduction of a particular animal model needs to be evaluated using appropriate tools, including the behavioral assessment of injury and non-invasive and post-mortem control of brain damage. These problems also have been summarized in the review.

  10. Cerebral calcifications and schizophreniform disorder

    Directory of Open Access Journals (Sweden)

    Leonardo Fernandez Meyer

    2013-01-01

    Full Text Available OBJECTIVES: Discuss pathophysiological aspects of cerebral calcifications (CC and highlight its importance related to the occurrence of neuropsychiatric syndromes. METHOD: Single case report. RESULT: Man 52 years old, 20 years after going through a total thyroidectomy, starts showing behavioral disturbance (psychotic syndrome. He was diagnosed as schizophrenic (paranoid subtype and submitted to outpatient psychiatric treatment. During a psychiatric admission to evaluate his progressive cognitive and motor deterioration, we identified a dementia syndrome and extensive cerebral calcifications, derived from iatrogenic hypoparathyroidism. CONCLUSION: The calcium and phosphorus disturbances, including hypoparathyroidism, are common causes of CC. Its symptoms can imitate psychiatric disorders and produce serious and permanent cognitive sequelae. The exclusion of organicity is mandatory in any psychiatric investigative diagnosis in order to avoid unfavorable outcomes, such as in the present case report.

  11. Estrogen intervention in microvascular morphology and choline acetyltransferase expression in rat hippocampal neurons in chronic cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Zhenjun Yang; Hongwei Yan; Guomin Zhang; Zhihong Chen; Jingfeng Xue

    2011-01-01

    We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7, 14 and 21 days. The results revealed that estrogen improved microvasculature in the hippocampus of chronic cerebral ischemic rats, upregulated Bcl-2 protein expression, downregulated Bax protein expression, increased choline acetyltransferase expression in hippocampal cholinergic neurons, and suppressed hippocampal neuronal apoptosis. These findings indicate that estrogen can protect hippocampal neurons in rats with chronic cerebral ischemia.

  12. Cerebral Palsy: A Dental Update

    OpenAIRE

    Sehrawat, Nidhi; Marwaha, Mohita; Bansal, Kalpana; Chopra, Radhika

    2014-01-01

    ABSTRACT Special and medically compromised patients present a unique population that challenges the dentist’s skill and knowledge. Providing oral care to people with cerebral palsy (CP) requires adaptation of the skills we use everyday. In fact, most people with mild or moderate forms of CP can be treated successfully in the general practice setting. This article is to review various dental considerations and management of a CP patient. How to cite this article: Sehrawat N, Marwaha M, Bansal ...

  13. Baclofen in Spastic Cerebral Palsy

    OpenAIRE

    J Akhundian

    2002-01-01

    To evaluate the effect of oral baclofen in spastic cerebral palsy (cp), we studied 40 children with different clinical types of spastic cp. Half of these children served as control group and the others received oral baclofen. All of them were treated with physiotherapy under equal conditions for 6 weeks. We used two methods, modified Ashworth scale and range of motion for evaluation. At the end of therapy we found a significant improvement in the baclofen group compared to control group. As a...

  14. Cerebral palsy in preterm infants

    OpenAIRE

    Demeši-Drljan Čila; Mikov Aleksandra; Filipović Karmela; Tomašević-Todorović Snežana; Knežević Aleksandar; Krasnik Rastislava

    2016-01-01

    Background/Aim. Cerebral palsy (CP) is one of the leading causes of neurological impairment in childhood. Preterm birth is a significant risk factor in the occurrence of CP. Clinical outcomes may include impairment of gross motor function and intellectual abilities, visual impairment and epilepsy. The aim of this study was to examine the relationships among gestational age, type of CP, functional ability and associated conditions. Methods. The sample size w...

  15. Hydrocephalus in cerebral venous thrombosis.

    Science.gov (United States)

    Zuurbier, Susanna M; van den Berg, René; Troost, Dirk; Majoie, Charles B; Stam, Jan; Coutinho, Jonathan M

    2015-01-01

    Increased intracranial pressure is common in cerebral venous thrombosis (CVT), but hydrocephalus is rarely reported in these patients. We examined the frequency, pathophysiology and associated clinical manifestations of hydrocephalus in patients with CVT admitted to our hospital between 2000 and 2010 (prospectively since July 2006). Hydrocephalus was defined as a bicaudate index larger than the 95th percentile for age, and/or a radial width of the temporal horn of ≥ 5 mm. We excluded patients in whom hydrocephalus was caused by a disease other than CVT or if it was iatrogenic. 20 out of 99 patients with CVT had hydrocephalus. 6 patients with hydrocephalus were excluded from the analysis. Patients with hydrocephalus more often had focal neurological deficits (86 vs. 49%, p = 0.02) and were more frequently comatose (43 vs. 16%, p = 0.06), as compared to patients without hydrocephalus. Deep cerebral venous thrombosis (64 vs. 9%, p hydrocephalus. Intraventricular hemorrhage was present in 1 patient with hydrocephalus, compared to none among patients without hydrocephalus (7 vs. 0%, p = 0.15). Outcome at follow-up was worse in patients with hydrocephalus (mRS 0-1, 36 vs. 68%, p = 0.02; mortality 29 vs. 9%, p = 0.07). Hydrocephalus occurs more frequently in cerebral venous thrombosis than previously believed, especially in patients with deep cerebral venous thrombosis and edema of the basal ganglia. The presence of hydrocephalus is associated with a worse clinical outcome, but a direct causal relation is unlikely. Routine shunting procedures are not advisable.

  16. Apraxia in deep cerebral lesions.

    OpenAIRE

    Agostoni, E; Coletti, A.; G. Orlando; Tredici, G

    1983-01-01

    In a series of 50 patients with cerebrovascular lesions (demonstrated with CT scan), seven patients had lesions located in the basal ganglia and/or thalamus. All these seven patients were apractic. Ideomotor apraxia was present in all patients; five also had constructional apraxia, and one had bucco-facial apraxia. None of the patients had utilisation apraxia. These observations indicated that apraxia is not only a "high cerebral (cortical) function", but may depend also on the integrity of s...

  17. Clinical studies on cerebral infarction

    International Nuclear Information System (INIS)

    Hemorrhagic infarction (HI) is termed as the infarction in which a large part of the necrotic tissue is stippled with small hemorrhage. The pathogenetic mechanism of this disease still remains controversial. Cerebral infarction has long been divided into two subtypes-thrombosis and embolism-according to the pathogenetic mechanisms. Clinical studies were carried out in 31 cases of HI with cerebral thrombosis. CT findings of these cases were classified into five groups according to both size of low density area which indicates regions of infarction and distribution of arterial supply. The low density area of Type I-Type III were observed in the area of the middle cerebral artery. That of Type IV was observed in the area of the internal capsule and basal ganglia. That of Type V was observed in the area of the posterior cerebral artery. CT reveals two patterns of HI -pattern A and pattern B-. The CT finding of pattern A is appearance of high density area in the low density area. The CT finding of pattern B is appearance of iso density area in the low density area. rCBF was measured by 133Xe inhalation technique in 21 patients with CT type I, II and III. Thereafter, with regard to the various findings in CT, the clinical findings and CBF findings, a comparative study was carried out on these ten groups. From the results of present studies, it is concluded that sequential changes of CBF in cases with pattern A are different from those with pattern B, and that CBF measurement does not permit an estimation of a patient's chance for functionary recovery after a stroke in acute and subacute stage but permits estimation of functional outcome in chronic stage. (J.P.N.)

  18. MRI in cerebral toxocaral disease.

    OpenAIRE

    Rüttinger, P; Hadidi, H

    1991-01-01

    Toxocara canis, the common roundworm in the dog, can cause "visceral larva migrans" syndrome in humans, which may include generalised illness, eosinophilia, and symptoms arising from larval invasion of different organs. Of these, the clinically most important are liver, lungs, eyes and CNS. Involvement of the different parts of the CNS in human toxocaral disease has been described, but not the CT or MRI appearances of the cerebral lesions. In one case with a single focal epileptic fit, CT was...

  19. Late cerebral ischaemia after subarachnoid haemorrhage

    DEFF Research Database (Denmark)

    Edvinsson, L; Povlsen, G K

    2011-01-01

    Late cerebral ischaemia after subarachnoid haemorrhage (SAH) carries high morbidity and mortality because of reduced cerebral blood flow (CBF) and subsequent cerebral ischaemia. This is associated with upregulation of contractile receptors in cerebral artery smooth muscles via the activation...... of intracellular signalling. In addition, delayed cerebral ischaemia after SAH is associated with inflammation and disruption of the blood-brain barrier (BBB). This article reviews recent evidence concerning the roles of vasoconstrictor receptor upregulation, inflammation and BBB breakdown in delayed cerebral...... their sensitivity to endogenous agonists such as ET-1 and 5-HT by increasing their smooth muscle expression of receptors for these after SAH. This is associated with reduced CBF and neurological deficits. A number of signal transduction components mediating this receptor upregulation have been identified, including...

  20. Acute hypoxia increases the cerebral metabolic rate

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob;

    2016-01-01

    imaging techniques were used to measure global cerebral blood flow and the venous oxygen saturation in the sagittal sinus. Global cerebral metabolic rate of oxygen was quantified from cerebral blood flow and arteriovenous oxygen saturation difference. Concentrations of lactate, glutamate, N......-acetylaspartate, creatine and phosphocreatine were measured in the visual cortex by magnetic resonance spectroscopy. Twenty-three young healthy males were scanned for 60 min during normoxia, followed by 40 min of breathing hypoxic air. Inhalation of hypoxic air resulted in an increase in cerebral blood flow of 15.5% (p = 0.......058), and an increase in cerebral metabolic rate of oxygen of 8.5% (p = 0.035). Cerebral lactate concentration increased by 180.3% ([Formula: see text]), glutamate increased by 4.7% ([Formula: see text]) and creatine and phosphocreatine decreased by 15.2% (p[Formula: see text]). The N-acetylaspartate concentration...

  1. Transient cerebral hypoperfusion and hypertensive events during atrial fibrillation: a plausible mechanism for cognitive impairment.

    Science.gov (United States)

    Anselmino, Matteo; Scarsoglio, Stefania; Saglietto, Andrea; Gaita, Fiorenzo; Ridolfi, Luca

    2016-06-23

    Atrial fibrillation (AF) is associated with an increased risk of dementia and cognitive decline, independent of strokes. Several mechanisms have been proposed to explain this association, but altered cerebral blood flow dynamics during AF has been poorly investigated: in particular, it is unknown how AF influences hemodynamic parameters of the distal cerebral circulation, at the arteriolar and capillary level. Two coupled lumped-parameter models (systemic and cerebrovascular circulations, respectively) were here used to simulate sinus rhythm (SR) and AF. For each simulation 5000 cardiac cycles were analyzed and cerebral hemodynamic parameters were calculated. With respect to SR, AF triggered a higher variability of the cerebral hemodynamic variables which increases proceeding towards the distal circulation, reaching the maximum extent at the arteriolar and capillary levels. This variability led to critical cerebral hemodynamic events of excessive pressure or reduced blood flow: 303 hypoperfusions occurred at the arteriolar level, while 387 hypertensive events occurred at the capillary level during AF. By contrast, neither hypoperfusions nor hypertensive events occurred during SR. Thus, the impact of AF per se on cerebral hemodynamics candidates as a relevant mechanism into the genesis of AF-related cognitive impairment/dementia.

  2. MR findings of cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang Hum; Chang, Seung Kuk; Cho, Mee Young; Park, Dong Woo; Kim, Jong Deok; Eun, Choong Ki [Pusan Paik Hospital, Pusan (Korea, Republic of)

    1994-11-15

    To evaluate the MR findings of brain damage in cerebral palised patients and to correlate it with gestational age and the time of damage. A retrospective analysis was performed in 40 patients who underwent MR scanning for evaluation of brain lesion in clinically diagnosed cerebral palsy. Authors classified the patients into two groups as premature and full-term and compared MR findings of the two groups. Abnormal MR findings were noted in 28 cases (70%). Five out of 6 patients who had been born prematurely showed isolate periventricular white matter lesions. Twenty-three out of 34 patients who had been born at full-term showed abnormal MR findings. Of these 23 patients, migration anomalies in 7 patients, isolate periventricular white matter lesions in 3 patients, and other combined periventricular subcortical white matter and deep gray matter lesions in 14 patients were seen. At least, 10 patients(43%) of full term group showed abnormal MRI findings reflecting intrauterine brain damage and all 5 patients of premature group showed isolate periventricular white matter lesions suggesting immaturity of brain. MRI is thought to be very useful in the assessment of brain damage for the patients with cerebral palsy by recognizing the location of the lesion and estimating the time of damage.

  3. MR findings of cerebral palsy

    International Nuclear Information System (INIS)

    To evaluate the MR findings of brain damage in cerebral palised patients and to correlate it with gestational age and the time of damage. A retrospective analysis was performed in 40 patients who underwent MR scanning for evaluation of brain lesion in clinically diagnosed cerebral palsy. Authors classified the patients into two groups as premature and full-term and compared MR findings of the two groups. Abnormal MR findings were noted in 28 cases (70%). Five out of 6 patients who had been born prematurely showed isolate periventricular white matter lesions. Twenty-three out of 34 patients who had been born at full-term showed abnormal MR findings. Of these 23 patients, migration anomalies in 7 patients, isolate periventricular white matter lesions in 3 patients, and other combined periventricular subcortical white matter and deep gray matter lesions in 14 patients were seen. At least, 10 patients(43%) of full term group showed abnormal MRI findings reflecting intrauterine brain damage and all 5 patients of premature group showed isolate periventricular white matter lesions suggesting immaturity of brain. MRI is thought to be very useful in the assessment of brain damage for the patients with cerebral palsy by recognizing the location of the lesion and estimating the time of damage

  4. Assessment of the hand in cerebral palsy

    OpenAIRE

    Praveen Bhardwaj; S Raja Sabapathy

    2011-01-01

    Cerebral palsy is the musculoskeletal manifestation of a nonprogressive central nervous system lesion that usually occurs due to a perinatal insult to the brain. Though the cerebral insult is static the musculoskeletal pathology is progressive. Some patients with cerebral palsy whose hands are affected can be made better by surgery. The surgical procedures as such are not very technically demanding but the assessment, decision-making, and selecting the procedures for the given patient make th...

  5. Cerebral energy metabolism during induced mitochondrial dysfunction

    DEFF Research Database (Denmark)

    Nielsen, T H; Bindslev, TT; Pedersen, S M;

    2013-01-01

    In patients with traumatic brain injury as well as stroke, impaired cerebral oxidative energy metabolism may be an important factor contributing to the ultimate degree of tissue damage. We hypothesize that mitochondrial dysfunction can be diagnosed bedside by comparing the simultaneous changes...... in brain tissue oxygen tension (PbtO(2)) and cerebral cytoplasmatic redox state. The study describes cerebral energy metabolism during mitochondrial dysfunction induced by sevoflurane in piglets....

  6. Parental age, genetic mutation, and cerebral palsy.

    OpenAIRE

    Fletcher, N A; Foley, J

    1993-01-01

    Parental age and birth order were studied in 251 patients with cerebral palsy. No parental age or birth order effects were observed in spastic quadriplegia or diplegia, but a paternal age effect was detected in those with athetoid/dystonic cerebral palsy and congenital hemiplegia. These observations indicate that some cases of athetoid/dystonic or hemiplegic cerebral palsy might arise by fresh dominant genetic mutation.

  7. Cerebral palsy in very low birthweight infants.

    OpenAIRE

    Cooke, R W

    1990-01-01

    Eighty one very low birthweight survivors with cerebral palsy were matched with controls by sex, gestational age, and place of birth. Using discriminant analysis, the perinatal profiles for infants with cerebral palsy and their controls were shown to differ significantly. When infants with various types of cerebral palsy were analysed with their controls the discriminating variables differed. Diplegic infants could be differentiated from controls on antenatal variables alone, but significant ...

  8. Evaluation measures for children with cerebral palsy

    OpenAIRE

    Sršen, Katja Groleger

    2013-01-01

    Abstract. Cerebral palsy is a well-recognized neurodevelopmental condition. The most recentdefinition describes cerebral palsy as a group of disorders of movement andposture, causing activity limitation. An important step in the process of(re)habilitation is evaluation of functional abilities of an individual. To beas accurate as possible in the evaluation of functioning, proper measurementinstruments have to be used. There are many different measurement tools forchildren with cerebral palsy,...

  9. Epilepsy in children with cerebral palsy

    OpenAIRE

    Bruck Isac; Antoniuk Sérgio Antônio; Spessatto Adriane; Bem Ricardo Schmitt de; Hausberger Romeu; Pacheco Carlos Gustavo

    2001-01-01

    OBJECTIVE: To describe the prevalence and characteristics of epilepsy in patients with cerebral palsy in a tertiary center. METHODS: a total of 100 consecutive patients with cerebral palsy were retrospectively studied. Criteria for inclusion were follow-up period for at least 2 years. Types and incidence of epilepsy were correlated with the different forms of cerebral palsy. Other factors associated with epilepsy such as age of first seizure, neonatal seizures and family history of epilepsy w...

  10. A study on the pathogenesis of human cerebral malaria and cerebral babesiosis

    Directory of Open Access Journals (Sweden)

    Masamichi Aikawa

    1992-01-01

    Full Text Available Cerebral complications are important, but poorly understood pathological features of infections caused by some species of Plasmodium and Babesia. Patients dying from P. falciparum were classified as cerebral or non-cerebral cases according to the cerebral malaria coma scale. Light microscopy revealed that cerebral microvessels of cerebral malaria patients were field with a mixture of parazited and unparazited erythrocytes, with 94% of the vessels showing parasitized red blood cell (PRBC sequestration. Some degree of PRBC sequestration was also found in non-cerebral malaria patients, but the percentage of microvessls with sequestered PRBC was only 13% Electron microscopy demonstrated knobs on the membrane of PRBC that formed focal junctions with the capillary endothelium. A number of host cell molecules such as CD36, thrombospondim (TSP and intracellular adhesion molecule I (ICAM-1 may function as endothelial cell surfacereports for P. falciparum-infected erythrocytes. Affinity labeling of CD36 and TSP to the PRBC surface showed these molecules specifically bind to the knobs. Babesia bovis infected erythrocytes procedure projections of the erythrocyte membrane that are similar to knobs. When brain tissue from B. bovis-infected cattle was examined, cerebral capillaries were packed with PRBC. Infected erythrocytes formed focal attachments with cerebral endothelial cells at the site of these knob-like projections. These findings indicate that cerebral pathology caused by B. bovis is similar to human cerebral malaria. A search for cytoadherence proteins in the endothelial cells may lead to a better understanding of the pathogenisis of cerebral babesiosis.

  11. Cerebral Palsy. Fact Sheet = La Paralisis Cerebral. Hojas Informativas Sobre Discapacidades.

    Science.gov (United States)

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on cerebral palsy is written in both English and Spanish. First, it provides a definition of cerebral palsy and considers various causes (e.g., an insufficient amount of oxygen reaching the fetal or newborn brain). The fact sheet then offers incidence figures and explains characteristics of the three main types of cerebral palsy:…

  12. Cerebritis: An unusual complication of Klebsiella pneumoniae

    Directory of Open Access Journals (Sweden)

    Majumdar Mainak

    2009-01-01

    Full Text Available Cerebritis is part of a continuum of brain infection and is difficult to diagnose. Cerebritis caused by Klebsiella in immunocompetent adults without predisposing factors such as neurosurgery or penetrating brain injury has not been reported before. We report a case of Klebsiella cerebritis in an adult patient with a proven extracranial focus of infection. We suggest considering cerebritis as a differential diagnosis for altered level of consciousness in patients of severe sepsis, even if an extracranial source of infection is proven.

  13. Correcting partial volume artifacts of the arterial input function in quantitative cerebral perfusion MRI

    NARCIS (Netherlands)

    van Osch, MJP; Vonken, EJPA; Bakker, CJG; Viergever, MA

    2001-01-01

    To quantify cerebral perfusion with dynamic susceptibility contrast MRI (DSC-MRI), one needs to measure the arterial input function (AIF). Conventionally, one derives the contrast concentration from the DSC sequence by monitoring changes in either the amplitude or the phase signal on the assumption

  14. Clinicopathological features of cerebral lipoastrocytoma

    Directory of Open Access Journals (Sweden)

    Shuang WEN

    2014-01-01

    Full Text Available Objective To explore the clinicopathological features, immune phenotype, diagnosis and differential diagnosis, treatment and prognosis of cerebral lipoastrocytoma. Methods Retrospective analysis of the clinical manifestations, histopathological and immunohistochemical features were conducted in one case of cerebral lipoastrocytoma. Results A 48-year-old male presented with numbness and inflexibility of the fourth and little fingers of his left hand over the previous 2 weeks. Cranial MRI revealed a space-occupying lesion with cystic degeneration in the right parietal lobe that showed obvious enhancement after contrast administration. The patient subsequently underwent craniotomy with stereotactic gross total excision of the lesion. Adjuvant chemotherapy and radiation therapy were not administered. Histologically the tumor showed classical features of low-grade astrocytoma, including a few scattered medium-large neuron-like cells with prominent nucleoli and abundant cytoplasm. Most notably, the glial cells contained fat droplets or vacuoles giving an appearance of mature adipocytes. Focally microcystic change was evident resulting from adipocyte-like cells fusion with each other. Immunohistochemically, the tumor cells were reactive for glial fibrillary acidic protein (GFAP and S-100 protein (S-100, focally positive for WT-1, weakly positive for oligodendrocytes transcription factor-2 (Olig-2, and negative for isocitrate dehydrogenase 1 (IDH1. Meanwhile, the tumor cells also expressed several neuronal markers including synaptophysin (Syn, microtube-associated protein-2 (MAP-2, neurofilament (NF, neuron specific enolase (NSE and CD34. P53 protein was weakly expressed in 5% of tumor cells. Ki-67 labeling index was low (1% . The patient remained well without recurrence 20 months after surgery. Conclusions Cerebral lipoastrocytoma is an extremely rare tumor. Histologically, the tumor showed classical features of low-grade astrocytoma and extensive

  15. A Family of Salmonella Virulence Factors Functions as a Distinct Class of Autoregulated E3 Ubiquitin Ligases

    Energy Technology Data Exchange (ETDEWEB)

    Quezada, C.; Hicks, S; Galan, J; Stebbins, C

    2009-01-01

    Processes as diverse as receptor binding and signaling, cytoskeletal dynamics, and programmed cell death are manipulated by mimics of host proteins encoded by pathogenic bacteria. We show here that the Salmonella virulence factor SspH2 belongs to a growing class of bacterial effector proteins that harness and subvert the eukaryotic ubiquitination pathway. This virulence protein possesses ubiquitination activity that depends on a conserved cysteine residue. A crystal structure of SspH2 reveals a canonical leucine-rich repeat (LRR) domain that interacts with a unique E{sub 3} ligase [which we have termed NEL for Novel E{sub 3} Ligase] C-terminal fold unrelated to previously observed HECT or RING-finger E{sub 3} ligases. Moreover, the LRR domain sequesters the catalytic cysteine residue contained in the NEL domain, and we suggest a mechanism for activation of the ligase requiring a substantial conformational change to release the catalytic domain for function. We also show that the N-terminal domain targets SspH2 to the apical plasma membrane of polarized epithelial cells and propose a model whereby binding of the LRR to proteins at the target site releases the ligase domain for site-specific function.

  16. Sumatriptan and cerebral perfusion in healthy volunteers.

    Science.gov (United States)

    Scott, A K; Grimes, S; Ng, K; Critchley, M; Breckenridge, A M; Thomson, C; Pilgrim, A J

    1992-04-01

    1. The effect of sumatriptan on regional cerebral perfusion was studied in healthy volunteers. 2. Intravenous sumatriptan (2 mg) had no detectable effect on regional cerebral perfusion as measured using a SPECT system with 99technetiumm labelled hexemethylpropyleneamineoxime. 3. Sumatriptan had no effect on pulse, blood pressure or ECG indices. 4. All six volunteers experienced minor adverse effects during the intravenous infusion.

  17. Assistive technology for people with cerebral palsy

    OpenAIRE

    Zupan, Anton; Jenko, Mojca

    2013-01-01

    Abstract. Assistive technology includes equipment, devicesand software solutions that increase functional capabilities of people withdisabilities and improve the quality of their lives. The article presentsassistive technology for people with cerebral palsy. These are mobility aidsthat enable people with cerebral palsy independent walking. For those whocannot walk, proper seating is very important. People, who cannot propel manualwheelchair, can control electric wheelchair with various contro...

  18. Cerebral emboli and depressive symptoms in dementia.

    NARCIS (Netherlands)

    Purandare, N.; Oude Voshaar, R.C.; Hardicre, J.; Byrne, J.; McCollum, C.N.; Burns, A.

    2006-01-01

    BACKGROUND: The vascular depression hypothesis and our recent findings of increased frequency of spontaneous cerebral emboli in dementia suggest that such emboli may be involved in the causation of depressive symptoms in dementia. AIMS: To evaluate the association between spontaneous cerebral emboli

  19. Ataxic cerebral palsy and genetic predisposition.

    OpenAIRE

    Miller, G.

    1988-01-01

    It was calculated that in the 962 family members of 36 patients with ataxic cerebral palsy there were 75 (8%) with a history of neurodevelopmental disorder and 31 (3%) with a major congenital malformation. This was not significantly greater than expected, and does not support the hypothesis of a genetic non-Mendelian role in the aetiology of ataxic cerebral palsy.

  20. Fatal cerebral oedema in adult diabetic ketoacidosis.

    NARCIS (Netherlands)

    Haringhuizen, A.; Tjan, D.H.; Grool, A.; Vugt, R. van; Zante, A.R. van

    2010-01-01

    In this report, a case of adult onset fatal cerebral oedema as a rare complication of diabetic ketoacidosis (DKA) is described and confirmed at post-mortem pathological examination. The pathogenesis of cerebral oedema due to DKA is still unknown. Potential mechanisms include the administration of so

  1. Mobility Experiences of Adolescents with Cerebral Palsy

    Science.gov (United States)

    Palisano, Robert J.; Shimmell, Lorie J.; Stewart, Debra; Lawless, John J.; Rosenbaum, Peter L.; Russell, Dianne J.

    2009-01-01

    The purpose of this study was to describe how youth with cerebral palsy experience mobility in their daily lives using a phenomenological approach. The participants were 10 youth with cerebral palsy, 17 to 20 years of age, selected using purposeful sampling with maximum variation strategies. A total of 14 interviews were completed. Transcripts…

  2. Cerebral oximetry in cardiac anesthesia

    Science.gov (United States)

    Vretzakis, George; Georgopoulou, Stauroula; Stamoulis, Konstantinos; Stamatiou, Georgia; Tsakiridis, Kosmas; Katsikogianis, Nikolaos; Kougioumtzi, Ioanna; Machairiotis, Nikolaos; Tsiouda, Theodora; Mpakas, Andreas; Beleveslis, Thomas; Koletas, Alexander; Siminelakis, Stavros N.; Zarogoulidis, Konstantinos

    2014-01-01

    Cerebral oximetry based on near-infrared spectroscopy (NIRS) is increasingly used during the perioperative period of cardiovascular operations. It is a noninvasive technology that can monitor the regional oxygen saturation of the frontal cortex. Current literature indicates that it can stratify patients preoperatively according their risk. Intraoperatively, it provides continuous information about brain oxygenation and allows the use of brain as sentinel organ indexing overall organ perfusion and injury. This review focuses on the clinical validity and applicability of this monitor for cardiac surgical patients. PMID:24672700

  3. Cerebral salt wasting syndrome: review.

    Science.gov (United States)

    Cerdà-Esteve, M; Cuadrado-Godia, E; Chillaron, J J; Pont-Sunyer, C; Cucurella, G; Fernández, M; Goday, A; Cano-Pérez, J F; Rodríguez-Campello, A; Roquer, J

    2008-06-01

    Hyponatremia is the most frequent electrolyte disorder in critically neurological patients. Cerebral salt wasting syndrome (CSW) is defined as a renal loss of sodium during intracranial disease leading to hyponatremia and a decrease in extracellular fluid volume. The pathogenesis of this disorder is still not completely understood. Sympathetic responses as well as some natriuretic factors play a role in this syndrome. Distinction between SIADH and CSW might be difficult. The essential point is the volemic state. It is necessary to rule out other intermediate causes. Treatment requires volume replacement and maintenance of a positive salt balance. Mineral corticoids may be useful in complicated cases.

  4. ECG changes during cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.; Nishimura, Y.; Yoshida, M.; Itoh, K.; Hayashi, N.; Aoki, J.; Nakamura, K.; Imai, M.; Ono, T.; Morikawa, S.

    1984-09-01

    We have analyzed HR changes greater than 20% among 334 patients and 942 cerebral angiographies. A tachycardial effect was seen in 14.9% of patients, while a bradycardial effect was seen in 7.1% including two patients having cardiac standstill (0.5%). These two patients were examined without atropine premedication after subarachnoid hemorrhage. Patients under 19 years of age, unpremedicated with atropine sulfate and suffering from subarachnoid hemorrhage secondary to ruptured aneurysm or arteriovenous malformation showed a significantly high incidence of bradycardia. On the other hand, patients with the neoplastic disease and having an initial sinus bradycardia showed a significantly high incidence of a tachycardial effect.

  5. Validation of CFD Simulations of Cerebral Aneurysms With Implication of Geometric Variations

    OpenAIRE

    Hoi, Yiemeng; Woodward, Scott H.; Kim, Minsuok; Taulbee, Dale B.; Meng, Hui

    2006-01-01

    Computational fluid dynamics (CFD) simulations using medical-image-based anatomical vascular geometry are now gaining clinical relevance. This study aimed at validating the CFD methodology for studying cerebral aneurysms by using particle image velocimetry (PIV) measurements, with a focus on the effects of small geometric variations in aneurysm models on the flow dynamics obtained with CFD. Method of Approach. An experimental phantom was fabricated out of silicone elastomer to best mimic a sp...

  6. CT findings in patients with cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Konno, K. (Akita Univ. (Japan))

    1982-01-01

    Clinical findings and CT findings in 73 cases of cerebral palsy were studied. The causes of cerebral palsy were presumed to be as follows: abnormal cerebral development (36%), asphyxial delivery (34%), and immature delivery (19%), etc. CT findings were abnormal in 58% of the 73 cases, 83% of the spastic tetraplegia patients and all of the spastic hemiplegia patients showed abnormal CT findings. All the patients with spastic monoplegia presented normal CT findings. In 75% of the spastic hemiplegia cases, the CT abnormalities were due to cerebral parenchymal abnormality such as porencephaly and regional low absorption. In cases of spastic tetraplegia, cerebral parenchymal abnormality was found only in 10%. Cortical atrophy was found only in 15 of the 73 cases, whereas central atrophy was found in 36 cases.

  7. CT findings in patients with cerebral palsy

    International Nuclear Information System (INIS)

    Clinical findings and CT findings in 73 cases of cerebral palsy were studied. The causes of cerebral palsy were presumed to be as follows: abnormal cerebral development (36%), asphyxial delivery (34%), and immature delivery (19%), etc. CT findings were abnormal in 58% of the 73 cases, 83% of the spastic tetraplegia patients and all of the spastic hemiplegia patients showed abnormal CT findings. All the patients with spastic monoplegia presented normal CT findings. In 75% of the spastic hemiplegia cases, the CT abnormalities were due to cerebral parenchymal abnormality such as porencephaly and regional low absorption. In cases of spastic tetraplegia, cerebral parenchymal abnormality was found only in 10%. Cortical atrophy was found only in 15 of the 73 cases, whereas central atrophy was found in 36 cases. (Ueda, J.)

  8. Middle cerebral artery flow velocity and blood flow during exercise and muscle ischemia in humans

    DEFF Research Database (Denmark)

    Jørgensen, L G; Perko, M; Hanel, B;

    1992-01-01

    ," mechanoreceptors, and/or muscle "metaboreceptors" on cerebral perfusion. Ten healthy subjects performed two levels of dynamic exercise corresponding to a heart rate of 110 (range 89-134) and 148 (129-170) beats/min, respectively, and exhaustive one-legged static knee extension. Measurements were continued during 2......, they support the hypothesis that cerebral perfusion during exercise reflects an increase in brain activation that is independent of MAP, central command, and muscle metaboreceptors but is likely to depend on influence of mechanoreceptors....

  9. Vascular permeability in cerebral cavernous malformations.

    Science.gov (United States)

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao; Girard, Romuald; Shenkar, Robert; Guo, Xiaodong; Shah, Akash; Larsson, Henrik B W; Tan, Huan; Li, Luying; Wishnoff, Matthew S; Shi, Changbin; Christoforidis, Gregory A; Awad, Issam A

    2015-10-01

    Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case-controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive familial CCM disease had greater WMF permeability compared to those with milder disease phenotype, but similar lesion permeability. Subjects receiving statin medications for routine cardiovascular indications had a trend of lower WMF, but not lesion, permeability. This is the first demonstration of brain vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy.

  10. Dynamic changes of neutrophil elastase concentration in cerebral tissue from traumatic brain injury rats%中性粒细胞弹性蛋白酶在颅脑损伤大鼠脑组织中的动态变化

    Institute of Scientific and Technical Information of China (English)

    苏海; 贺学农; 陈皓; 周昌龙; 夏小辉; 张毅

    2013-01-01

    目的 探讨颅脑损伤(TBI)大鼠脑组织中的中性粒细胞弹性蛋白酶(NE)动态变化和血脑屏障通透性及脑含水率的关系.方法 SD大鼠48只,随机分为对照组和TBI组(包括伤后6、24、48、72、168 h),复制大鼠液压打击模型,测定脑组织NE的含量、脑含水量及血脑屏障通透性.结果 TBI组大鼠脑组织NE含量和血脑屏障通透性呈同步性变化,从6h开始升高,48 h达最高峰,72 h逐渐下降,168 h仍高于对照组;TBI大鼠脑组织含水率72 h达最高峰;TBI组大鼠脑组织NE含量、血脑屏障通透性和脑组织含水率在各时间点均高于对照组(P<0.05).结论 TBI大鼠脑组织内NE含量升高与大鼠伤后血脑屏障开放、脑组织水肿密切相关,NE增加可能是脑创伤后引起血脑屏障开放、脑水肿形成的重要原因之一.%Objective To explore the relationship between the dynamic changes of neutrophil elastase ( NE) in traumatic brain inju ry (TBI) rats and blood brain barrier( BBB) permeability as well as the cerebral water content. Methods 48 SD rats were randomly divided into control group and TBI groups (including 6,24,48,72 and 168 h subgroups). The severely head injured rat models are made by fluid shock, and the content of NE and water as well as BBB permeability in brain tissues were tested. Results NE content and BBB permeability in brain tissues of TBI groups were simultaneously related, and they started going up at 6 h, reached the highest peak at 48 h, started gradu ally going down at 72 h and were still higher than those of control group at 168 h; the water content in brain tissues of TBI rats reached the highest peak at 72 h; the content of NE and water as well as BBB permeability in brain tissues of TBI rats were higher than those of control group at all time (P < 0. 05 ). Conclusions The increase of NE content in brain tissues of TBI rats is closely associated with the opening of BBB and cerebral edema after the trauma. The

  11. The influence of tobacco smoking on the relationship between pressure and flow in the middle cerebral artery in humans.

    Directory of Open Access Journals (Sweden)

    Karen C Peebles

    Full Text Available BACKGROUND: Cigarette smoking is associated with an increased risk of stroke but the mechanism is unclear. The study examined whether acute and chronic cigarette smoking alters the dynamic relationship between blood pressure and cerebral blood flow. We hypothesised that acute and chronic smoking would result in a cerebral circulation that was less capable of buffering against dynamic fluctuations in blood pressure. Further, these changes would be accompanied by a reduction in baroreflex sensitivity, which is reduced after smoking (acute smoking. METHODS: We recruited 17 non-smokers and 15 habitual smokers (13 ± 5 pack years. Continuous measurements of mean cerebral blood flow velocity (transcranial Doppler ultrasound, blood pressure (finger photoplethysmography and heart rate enabled transfer function analysis of the dynamic relationship between pressure and flow (gain, normalised gain, phase and coherence and baroreflex sensitivity during supine rest before and after smoking a single cigarette (acute smoking. RESULTS: There were no between-group differences in gain, phase or coherence before acute smoking. However, both groups showed a reduction in gain and coherence, associated with a reduction in baroreflex sensitivity, and increase in phase after acute smoking. CONCLUSIONS: Contrary to our hypothesis, these findings suggest that in the face of a reduction in baroreflex sensitivity acute smoking may potentially improve the ability of the cerebral circulation to buffer against changes in blood pressure. However, chronic smoking did not alter the dynamic relationship between blood pressure and cerebral blood flow velocity. These results have implications on understanding mechanisms for attenuating stroke risk.

  12. Cerebral cortex modulation of pain

    Institute of Scientific and Technical Information of China (English)

    Yu-feng XIE; Fu-quan HUO; Jing-shi TANG

    2009-01-01

    Pain is a complex experience encompassing sensory-discriminative, affective-motivational and cognitiv e-emotional com-ponents mediated by different mechanisms. Contrary to the traditional view that the cerebral cortex is not involved in pain perception, an extensive cortical network associated with pain processing has been revealed using multiple methods over the past decades. This network consistently includes, at least, the anterior cingulate cortex, the agranular insular cortex, the primary (SⅠ) and secondary somatosensory (SⅡ) cortices, the ventrolateral orbital cortex and the motor cortex. These corti-cal structures constitute the medial and lateral pain systems, the nucleus submedius-ventrolateral orbital cortex-periaque-ductal gray system and motor cortex system, respectively. Multiple neurotransmitters, including opioid, glutamate, GABA and dopamine, are involved in the modulation of pain by these cortical structures. In addition, glial cells may also be in-volved in cortical modulation of pain and serve as one target for pain management research. This review discusses recent studies of pain modulation by these cerebral cortical structures in animals and human.

  13. [Cerebral vasospasm after subarachnoid hemorrhage].

    Science.gov (United States)

    Milojević, T M; Baljozović, B V; Rakić, M Lj; Nestorović, B D; Dostanić, M M; Milaković, B D; Kojić, Z Z; Repac, N R; Cvrkota, I S

    2008-01-01

    Cerebral vasospasm causes permanent neurolological deficit or death occurance in 13% of clinical cases. Peak frequency is from 8-10th day after SAH. The purpose of this study is factor analysis that may have influence on vasospasm development , as well as predictor determination. The study is prospective and analysis 192 patients treated in Institute of Neurosurgery, Clinical Centre of Serbia, Belgrade. The majority of patients were admitted in hospital in first four days after SAH, and 184 had GCS over 7. Univariate methods of factor analysis were used, and for significance of predictors influence testing multivariante regression analysis was used. Vasospasm occurred in 22,40% of all cases. No relationships have been found between sex, age, previous hypertension, timing of surgery, appearance of hydrocephalus and intracerebral hematoma, hypertermia or mean arterial blood pressure, with occurrence of cerebral vasospasm. Factors with significantly associated with the occurance of vasospasm were: hearth disease, hypernatriemia, Hct, clinical grade on admission as well as preoperative clinical grade and Fisher CT scan grade. In the first four days after SAH, Fisher scan grade, preoperative clinical grade and Hct, appeared as predictors. After four days, clinical grade on admission and hypernatiemia, showed as poredictors. PMID:18792575

  14. Cerebral lateralization in simultaneous interpretation.

    Science.gov (United States)

    Fabbro, F; Gran, L; Basso, G; Bava, A

    1990-07-01

    Cerebral asymmetries for L1 (Italian), L2 (English), and L3 (French, German, Spanish, or Russian) were studied, by using a verbal-manual interference paradigm, in a group of Italian right-handed polyglot female students at the Scuola Superiore di Lingue Moderne per Interpreti e Traduttori (SSLM-School for Interpreters and Translators) of the University of Trieste and in a control group of right-handed monolingual female students at the Medical School of the University of Trieste. In an automatic speech production task no significant cerebral lateralization was found for the mother tongue (L1) either in the interpreting students or in the control group; the interpreting students were not significantly lateralized for the third language (L3), while weak left hemispheric lateralization was shown for L2. A significantly higher degree of verbal-manual interference was found for L1 than for L2 and L3. A significantly higher disruption rate occurred in the meaning-based mode of simultaneous interpretation (from L2 into L1 and vice versa) than in the word-for-word mode (from L2 into L1 and vice versa). No significant overall or hemispheric differences were found during simultaneous interpretation from L1 into L2 or from L2 into L1. PMID:2207622

  15. Regulation of cerebral cortex development by Rho GTPases: insights from in vivo studies

    Directory of Open Access Journals (Sweden)

    Roberta eAzzarelli

    2015-01-01

    Full Text Available The cerebral cortex is the site of higher human cognitive and motor functions. Histologically, it is organized into six horizontal layers, each containing unique populations of molecularly and functionally distinct excitatory projection neurons and inhibitory interneurons. The stereotyped cellular distribution of cortical neurons is crucial for the formation of functional neural circuits and it is predominantly established during embryonic development. Cortical neuron development is a multiphasic process characterized by sequential steps of neural progenitor proliferation, cell cycle exit, neuroblast migration and neuronal differentiation. This series of events requires an extensive and dynamic remodeling of the cell cytoskeleton at each step of the process. As major regulators of the cytoskeleton, the family of small Rho GTPases has been shown to play essential functions in cerebral cortex development. Here we review in vivo findings that support the contribution of Rho GTPases to cortical projection neuron development and we address their involvement in the etiology of cerebral cortex malformations.

  16. Quantitative cerebral perfusion assessment using microscope-integrated analysis of intraoperative indocyanine green fluorescence angiography versus positron emission tomography in superficial temporal artery to middle cerebral artery anastomosis

    Directory of Open Access Journals (Sweden)

    Shinya Kobayashi

    2014-01-01

    Full Text Available Background: Intraoperative qualitative indocyanine green (ICG angiography has been used in cerebrovascular surgery. Hyperperfusion may lead to neurological complications after superficial temporal artery to middle cerebral artery (STA-MCA anastomosis. The purpose of this study is to quantitatively evaluate intraoperative cerebral perfusion using microscope-integrated dynamic ICG fluorescence analysis, and to assess whether this value predicts hyperperfusion syndrome (HPS after STA-MCA anastomosis. Methods: Ten patients undergoing STA-MCA anastomosis due to unilateral major cerebral artery occlusive disease were included. Ten patients with normal cerebral perfusion served as controls. The ICG transit curve from six regions of interest (ROIs on the cortex, corresponding to ROIs on positron emission tomography (PET study, was recorded. Maximum intensity (I MAX , cerebral blood flow index (CBFi, rise time (RT, and time to peak (TTP were evaluated. Results: RT/TTP, but not I MAX or CBFi, could differentiate between control and study subjects. RT/TTP correlated (|r| = 0.534-0.807; P < 0.01 with mean transit time (MTT/MTT ratio in the ipsilateral to contralateral hemisphere by PET study. Bland-Altman analysis showed a wide limit of agreement between RT and MTT and between TTP and MTT. The ratio of RT before and after bypass procedures was significantly lower in patients with postoperative HPS than in patients without postoperative HPS (0.60 ± 0.032 and 0.80 ± 0.056, respectively; P = 0.017. The ratio of TTP was also significantly lower in patients with postoperative HPS than in patients without postoperative HPS (0.64 ± 0.081 and 0.85 ± 0.095, respectively; P = 0.017. Conclusions: Time-dependent intraoperative parameters from the ICG transit curve provide quantitative information regarding cerebral circulation time with quality and utility comparable to information obtained by PET. These parameters may help predict the occurrence of postoperative

  17. Aerobic training in children with cerebral palsy.

    Science.gov (United States)

    Nsenga, A L; Shephard, R J; Ahmaidi, S; Ahmadi, S

    2013-06-01

    Rehabilitation is a major goal for children with cerebral palsy, although the potential to enhance cardio-respiratory fitness in such individuals remains unclear. This study thus compared current cardio-respiratory status between children with cerebral palsy and able-bodied children, and examined the ability to enhance the cardio-respiratory fitness of children with cerebral palsy by cycle ergometer training. 10 children with cerebral palsy (Gross Motor Function Classification System levels I and II) participated in thrice-weekly 30 min cycle ergometer training sessions for 8 weeks (mean age: 14.2±1.9 yrs). 10 additional subjects with cerebral palsy (mean age: 14.2±1.8 yrs) and 10 able-bodied subjects (mean age: 14.1±2.1 yrs) served as controls, undertaking no training. All subjects undertook a progressive cycle ergometer test of cardio-respiratory fitness at the beginning and end of the 8-week period. Cardio-respiratory parameters [oxygen intake V˙O2), ventilation V ˙ E) and heart rate (HR)] during testing were measured by Cosmed K4 b gas analyzer. The children with cerebral palsy who engaged in aerobic training improved their peak oxygen consumption, heart rate and ventilation significantly (pchildren with cerebral palsy can benefit significantly from cardio-respiratory training, and such training should be included in rehabilitation programs.

  18. Noninvasive optoacoustic monitoring of cerebral venous blood oxygenation in newborns

    Science.gov (United States)

    Petrov, Irene Y.; Wynne, Karon E.; Petrov, Yuriy; Esenaliev, Rinat O.; Richardson, C. Joan; Prough, Donald S.

    2012-02-01

    Cerebral ischemia after birth and during labor is a major cause of death and severe complications such as cerebral palsy. In the USA alone, cerebral palsy results in permanent disability of 10,000 newborns per year and approximately 500,000 of the total population. Currently, no technology is capable of direct monitoring of cerebral oxygenation in newborns. This study proposes the use of an optoacoustic technique for noninvasive cerebral ischemia monitoring by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, near-infrared optoacoustic system suitable for noninvasive monitoring of cerebral ischemia in newborns with normal weight (NBW), low birth-weight (LBW, 1500 - 2499 g) and very low birth-weight (VLBW, cerebral oxygenation would suggest that no therapy was necessary; conversely, evidence of cerebral ischemia would prompt therapy to increase cerebral blood flow.

  19. Influence of Different Contrast Agents on Dynamic Contrast-Enhanced MRI Ktrans in Cerebral Metastases: Comparison between 1.0 M Gadobutrol and 0.5M Gadopentetate Dimeglumine%不同对比剂对脑转移瘤MRI动态增强定量参数(Ktrans)的影响

    Institute of Scientific and Technical Information of China (English)

    范兵; 杜华睿; 王霄英; 宛然; 罗晶晶; 张珏

    2014-01-01

    目的 比较不同浓度对比剂(钆布醇与钆喷酸葡胺)对脑转移瘤容积转移常数(Ktrans)的影响.方法 招募10例脑转移瘤患者,签署知情同意书,采用个体内自身随机对照研究,所有患者均接受2次头颅MRI动态增强检查,分别注射2种不同对比剂.采用交叉设计,利用随机表确定注射钆布醇和钆喷酸葡胺的次序,两次检查间隔24~ 48 h.对比剂剂量0.1 mmol/kg体重,注药流率3.0 ml/s,注射对比剂同时启动MR动态增强检查,对直径>5 mm的病灶测量Ktrans值及细胞外血管外间隙(Ve)值.使用SPSS 13.0进行统计学处理,对2种不同对比剂所测Ktrans值及Ve值分别采用方差分析,进一步做Pearson相关性分析,P<0.05认为有统计学差异.结果 2例患者因病灶较小(直径<5 mm)无法测量Krans值而排除,对8例患者共21个病灶进行分析,钆布醇及钆喷酸葡胺所测Ktrans值分别为(0.32±0.19) min-1,(0.35±0.19) min-1 (F=0.315,P>0.05),两者Ve值分别为0.89±0.10,0.88±0.09(F =0.009,P>0.05).两种对比剂所测Ktrans值及Ve值均呈正相关(Ktrans:r =0.712,P<0.001;Ve:r=0.616,P<0.05).结论 使用不同含钆对比剂(钆布醇与钆喷酸葡胺)行MR动态增强扫描,对脑转移瘤病灶所测Ktrans及Ve值具有相关性.%Objective To explore the effect of different Gadolium-based contrast agents (gadobutrol vs.gadopentetate dimeglumine) on the measurement of volume transfer constant (Ktrans) and Ve in dynamic contrast enhanced MRI for cerebral metastases.Methods Ten patients with pathologically-confirmed cerebral metastases were examined by dynamic contrast-enhanced MR imaging with identical scanning protocol for two times.Gadobutrol or gadopentetate dimeglumine were randomly selected for the first study,with dosage of 0.1 mmol gadolium/kg body weight.Twenty-four to 48 hours later,the second study was performed with injection of the other contrast agent.The Ktrans and Ve values of the metastatic foci were

  20. The serpentine mitral valve and cerebral embolism

    Directory of Open Access Journals (Sweden)

    Ker James

    2011-02-01

    Full Text Available Abstract Valvular strands, well-delineated filiform masses, attached to cardiac valve edges are associated with cerebral embolism and stroke. Strokes, caused by emboli from valvular strands, tend to occur among younger persons. In this case report a valvular strand, giving a peculiar serpentine appearance to the mitral valve is described. This mitral valvular strand was the only explanation for an episode of cerebral embolism, presenting with a transient right sided hemiparesis. It is proposed that a randomized study involving combined treatment with aspirin and clopidogrel is warranted in young patients with valvular strands, presenting with a first episode of cerebral embolism.

  1. Validation of a cerebral palsy register

    DEFF Research Database (Denmark)

    Topp, Monica Wedell; Langhoff-Roos, J; Uldall, P

    1997-01-01

    OBJECTIVES: To analyse completeness and validity of data in the Cerebral Palsy Register in Denmark, 1979-1982. METHODS: Completeness has been assessed by comparing data from The Danish National Patient Register (DNPR) with the cases included in the Cerebral Palsy Register (CPR). Agreement between......, but gestational age was subject to a systematic error, and urinary infections in pregnancy (kappa = 0.43) and placental abruption (kappa = 0.52) were seriously under-reported in the CPR. CONCLUSIONS: Completeness of the Cerebral Palsy Register in Denmark, 1979-1982, has been assessed to maximal 85%, emphasizing...

  2. Trends in birth prevalence of cerebral palsy.

    OpenAIRE

    Pharoah, P O; Cooke, T.; Rosenbloom, I; Cooke, R W

    1987-01-01

    A register of children with cerebral palsy born in the period 1966-77 to mothers resident in the Mersey region was compiled from several different data sources. There were 685 cases, with a male:female ratio of 1.4:1. The birth prevalence of cerebral palsy ranged from 1.18 to 1.97 per 1000 live births each year, with a mean of 1.51 per 1000 live births. There was no discernible trend in overall prevalence, but there was a highly significant upward trend in the prevalence of cerebral palsy amo...

  3. Dihydralazine induces marked cerebral vasodilation in man

    DEFF Research Database (Denmark)

    Schroeder, T; Sillesen, H

    1987-01-01

    Dihydralazine is widely used for acute control of hypertension. In experimental studies it seems to dilate cerebral resistance vessels and increase intracranial pressure. However, the effect on cerebral blood flow (CBF) in man has been little studied. Measurements of CBF were performed with the i...... the period of study, in median 16, 27 and 23% at the three periods of measurements, respectively. The arterial blood pressure remained unchanged, whereas heart rate increased significantly. During CO2 inhalation, CBF increased on average 29%. Thus, the cerebral vasodilation exerted by a small i.v. dose...

  4. Cerebral Metabolic Alterations in Rats With Diabetic Ketoacidosis

    OpenAIRE

    Glaser, Nicole; Yuen, Natalie; Anderson, Steven E; Tancredi, Daniel J.; O'Donnell, Martha E.

    2009-01-01

    OBJECTIVE Cerebral edema is a life-threatening complication of diabetic ketoacidosis (DKA) in children. Recent data suggest that cerebral hypoperfusion and activation of cerebral ion transporters may be involved, but data describing cerebral metabolic alterations during DKA are lacking. RESEARCH DESIGN AND METHODS We evaluated 50 juvenile rats with DKA and 21 normal control rats using proton and phosphorus magnetic resonance spectroscopy (MRS). MRS measured cerebral intracellular pH and ratio...

  5. Role of Aquaporin-4 in Cerebral Edema and Stroke

    OpenAIRE

    Zador, Zsolt; Stiver, Shirley; Wang, Vincent; Manley, Geoffrey T.

    2009-01-01

    Cerebral edema plays a central role in the pathophysiology of many diseases of the central nervous system (CNS) including ischemia, trauma, tumors, inflammation, and metabolic disturbances. The formation of cerebral edema results in an increase in tissue water content and brain swelling which, if unchecked, can lead to elevated intracranial pressure (ICP), reduced cerebral blood flow, and ultimately cerebral herniation and death. Despite the clinical significance of cerebral edema, the mechan...

  6. Epilepsy in children with cerebral palsy Epilepsia em crianças com paralisia cerebral

    OpenAIRE

    Isac Bruck; Sérgio Antônio Antoniuk; Adriane Spessatto; Ricardo Schmitt de Bem; Romeu Hausberger; Carlos Gustavo Pacheco

    2001-01-01

    OBJECTIVE: To describe the prevalence and characteristics of epilepsy in patients with cerebral palsy in a tertiary center. METHODS: a total of 100 consecutive patients with cerebral palsy were retrospectively studied. Criteria for inclusion were follow-up period for at least 2 years. Types and incidence of epilepsy were correlated with the different forms of cerebral palsy. Other factors associated with epilepsy such as age of first seizure, neonatal seizures and family history of epilepsy w...

  7. Cerebral hyperperfusion following carotid endarterectomy

    DEFF Research Database (Denmark)

    Schroeder, T; Sillesen, H; Sørensen, O;

    1987-01-01

    Serial measurements of cerebral blood flow (CBF) were performed in 56 patients before and one to four times after uncomplicated carotid endarterectomy. The findings were related to the ratio between internal carotid artery (ICA) and common carotid artery (CCA) mean pressures. Within the 1st...... postoperative day CBF increased by a median of 37% in the ipsilateral and 33% in the contralateral hemisphere. Later recordings showed a gradual return of CBF toward the preoperative level. Sixteen patients with an ICA/CCA pressure ratio below 0.7 showed a significantly more pronounced and longer-lasting flow......, occurred in the low pressure ratio group, while the hemispheric asymmetry on average was unchanged in the high pressure ratio group. This relative hyperemia was most pronounced 2 to 4 days following reconstruction. The marked hyperemia, absolute as well as relative, in patients with a low ICA/CCA pressure...

  8. Computed tomography of cerebral palsy

    International Nuclear Information System (INIS)

    Seventy patients who had suffered from severe damages in the brain in their early lives were examined using a CT scanner, DELTA-25. The results are summerized as follows: 1. CT findings of the brain were classified into four groups; (1) low density in 11 cases, (2) atrophy in 23, (3) hydrocephalus in 12, and (4) no findings in 24. 2. The low density in the CT finding was assumed as cystic degeneration due to circulatory disturbance in the cerebral hemispheres in their early developmental stages. 3. The ''acerebrate'' state denotes no or little development in mental and motor functions which is attributed to a severe damage in the developing brain. According to the CT findings, the ''acerebrate'' state was resulted from extensive destruction in the greater part of both hemispheres. (author)

  9. Cerebral astroblastoma: A radiopathological diagnosis

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Singh

    2014-01-01

    Full Text Available Astroblastoma is a rare glial neoplasm whose histogenesis has been clarified recently. It primarily occurs in children and young adults. We are reporting a case of 12-year-old girl child who presented with features of raised intracranial tension and generalized tonic-clonic seizures. Brain magnetic resonance imaging revealed a large well-circumscribed, cystic lesion without perifocal edema, and enhancing mural nodule in right parietal region. A radiological differential diagnosis of pilocytic astrocytoma and cerebral astroblastoma was made. A complete excision was done and histologically the lesion turned out to be an astroblastoma. We review the histology, immunohistochemistry, and imaging features of astroblastoma and survey the current literature, treatment strategies, and prognostic aspects for the management of this rare neoplasm.

  10. Changes of cerebrospinal fluid circulation dynamics after cerebral trauma monitored with MRI 2D-phase contrast cine%磁共振2D-PC cine法监测外伤后脑脊液循环动力学改变

    Institute of Scientific and Technical Information of China (English)

    岳翠; 郏潜新; 欧阳林; 王文浩; 陈懿; 肖玉辉; 何平

    2011-01-01

    Objective To evaluate the application of MRI 2D-phase contrast cine technique (MR 2D-PC cine) in monitoring the changes of cerebrospinal fluid (CSF) circulation dynamics. Methods MR 2D-PC cine was performed in 40 cases which were considered to have changes in CSF circulation dynamics and 40 healthy volunteers. The average velocity and the net forward volume of CSF were measured and compared with the results measured by lumbar puncture. Results In cerebral trauma patients,the average velocity was 1. 100 (0. 895 -1.420)cm/s and the net forward volume was 0.073 (0.017 -0.124) ml in a cardiac cycle. In healthy volunteers, the average velocity was 1.306 (1.210 -1.360)cm/s and the forward volume was 0.081 (0.062-0.258)ml in a cardiac cycle. The average velocity of CSF in cerebral trauma patients was slower (P < 0.05) and net forward volume was less (P <0.05) than that in volunteer. Conclusion MR 2D-PC cine can quantitatively monitor the changes of CSF circulation after trauma and provide evidence for clinical treatment.%目的 运用MRI二维相位对比序列(2D-PC cine)法监测外伤后脑脊液动力学的改变.方法 采用MRI 2D-PC cine法序列,以编码流速20 cm/s,于枕骨大孔水平测量40例健康志愿者与40例脑外伤后临床怀疑脑循环动力学异常患者的脑脊液流速、流量,并与腰穿结果 相对照,比较两组脑脊液流速、流量之间有无差异.结果 外伤组平均流速为1.100 (0.895~1.420) cm/s,一个心动周期内净流量为0.073(0.017 ~0.124)ml,正常组平均流速为1.306 (1.210~1.360) cm/s,一个心动周期内平均净流量为0.081(0.062~0.258)ml.外伤组平均流速及净流量均小于对照组(P<0.05).结论 MRI 2D-PC cine能早期无创的发现脑外伤后颅内压增高患者脑脊液流体动力学的改变,对于脑外伤后患者脑脊液循环改变的监测、治疗及预后评价有重要指导意义.

  11. Cerebral palsy in preterm infants

    Directory of Open Access Journals (Sweden)

    Demeši-Drljan Čila

    2016-01-01

    Full Text Available Background/Aim. Cerebral palsy (CP is one of the leading causes of neurological impairment in childhood. Preterm birth is a significant risk factor in the occurrence of CP. Clinical outcomes may include impairment of gross motor function and intellectual abilities, visual impairment and epilepsy. The aim of this study was to examine the relationships among gestational age, type of CP, functional ability and associated conditions. Methods. The sample size was 206 children with CP. The data were obtained from medical records and included gestational age at birth, clinical characteristics of CP and associated conditions. Clinical CP type was determined according to Surveillance of Cerebral Palsy in Europe (SCPE and topographically. Gross motor function abilities were evaluated according to the Gross Motor Function Classification System (GMFCS. Results. More than half of the children with CP were born prematurely (54.4%. Statistically significant difference was noted with respect to the distribution of various clinical types of CP in relation to gestational age (p < 0.001. In the group with spastic bilateral CP type, there is a greater proportion of children born preterm. Statistically significant difference was noted in the functional classification based on GMFCS in terms of gestational age (p = 0.049, children born at earlier gestational age are classified at a higher GMFCS level of functional limitation. The greatest percentage of children (70.0% affected by two or more associated conditions was found in the group that had extremely preterm birth, and that number declined with increasing maturity at birth. Epilepsy was more prevalent in children born at greater gestational age, and this difference in distribution was statistically significant (p = 0.032. Conclusion. The application of antenatal and postnatal protection of preterm children should be a significant component of the CP prevention strategy. [Projekat Ministarstva nauke Republike

  12. Effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats

    Institute of Scientific and Technical Information of China (English)

    Zuoli Xia; Baoling Sun; Mingfeng Yang; Dongmei Hu; Tong Zhao; Jingzhong Niu

    2006-01-01

    BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel,it has lymphatic drain.Anterior lymphatic vessel in brain tissue plays a key role in introducing brain interstitial fluid to lymphatic system;however,the significance of lymphatic drain and the affect on cerebral edema remains unclear.OBJECTIVE: To investigate the effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats.DESIGN: Randomized controlled animal study.SETTING: Institute of Cerebral Microcirulation of Taishan Medical College and Department of Neurology of Affiliated Hospital.MATERIALS:A total of 63 healthy adult male Wistar rats weighing 300-350 g were selected in this study.Forty-seven rats were used for the morphological observation induced by lymphatic drain and randomly divided into three groups:general observation group(n=12),light microscopic observation group(n=21)and electronic microscopic observation group(n=14).The rats in each group were divided into cerebral lymphatic block subgroup and sham-operation control subgroup.Sixteen rats were divided into cerebral the effect of cerebral lymphatic block on cortical evoked potential,in which the animals were randomly divided into sham-operation group(n=6)and cerebral lymphatic block group(n=10).METHODS:The experiment was carried out in the Institute of Cerebral Microcirculation of Taishan Medical College from January to August 2003.Rats in cerebral lymphatic block group were anesthetized and separated bilateral superficial and deep cervical lymph nodes under sterile condition. Superior and inferior boarders of lymph nodes were ligated the inputting and outputting channels, respectively, and then lymph node was removed so as to establish cerebral lymphatic drain disorder models. Rats in sham-operation control group were not ligated the lymphatic vessel and removed lymph nodes.and other operations were as the same as those in cerebral lymphatic block group

  13. Comparison of Cerebral Oxygen Saturation and Cerebral Perfusion Computed Tomography in Cerebral Blood Flow in Patients with Brain Injury.

    Science.gov (United States)

    Trofimov, Alexey O; Kalentiev, George; Voennov, Oleg; Grigoryeva, Vera

    2016-01-01

    The purpose of this study was to determine the relationship between cerebral tissue oxygen saturation and cerebral blood volume in patients with traumatic brain injury. Perfusion computed tomography of the brain was performed in 25 patients with traumatic brain injury together with simultaneous SctO2 level measurement using cerebral near-infrared oxymetry. The mean age of the injured persons was 34.5±15.6 years (range 15-65); 14 men, 11 women. The Injury Severity Score (ISS) values were 44.4±9.7 (range 25-81). The Glasgow Coma Score (GCS) mean value before the study was 10.6±2.1 (range 5-13). SctO2 ranged from 51 to 89%, mean 62±8.2%. Cerebral blood volume (CBV) values were 2.1±0.67 ml/100 g (min 1.1; max 4.3 ml/100 g). Cerebral blood flow (CBF) was 31.99±13.6 ml/100 g×min. Mean transit time (MTT) values were 5.7±4.5 s (min 2.8; max 34.3 s). The time to peak (TTP) was 22.2±3.1 s. A statistically significant correlation was found between SctO2 level and cerebral blood volume (CBV) level (R=0.9; pperfusion.

  14. Cerebral malaria: gamma-interferon redux

    Directory of Open Access Journals (Sweden)

    Nicholas H Hunt

    2014-08-01

    Full Text Available There are two theories that seek to explain the pathogenesis of cerebral malaria, the mechanical obstruction hypothesis and the immunopathology hypothesis. Evidence consistent with both ideas has accumulated from studies of the human disease and experimental models. Thus some combination of these concepts seems necessary to explain the very complex pattern of changes seen in cerebral malaria. The interactions between malaria parasites, erythrocytes, the cerebral microvascular endothelium, brain parenchymal cells, platelets and microparticles need to be considered. One factor that seems able to knit together much of this complexity is the cytokine interferon-gamma. In this review we consider findings from the clinical disease, in vitro models and the murine counterpart of human cerebral malaria in order to evaluate the roles played by interferon-gamma in the pathogenesis of this often fatal and debilitating condition.

  15. Research progress of cerebral small vessel disease

    Directory of Open Access Journals (Sweden)

    Jun-dong JIA

    2015-03-01

    Full Text Available Cerebral small vessel disease refers to a group of pathological processes with various etiologies that affect small arteries, arterioles, venules, and capillaries of the brain. Recently, the researches of cerebral small vessel disease have got initial progressions, and a definite diagnosis of this disease is comfirmed by biopsy. Given the pathological material is difficult to obtain, clinicians should pay more attention to the imaging features and clinical manifestations. Correct understanding of imaging and clinical manifestations contributes to the early identification of cerebral small vessel disease. Herein, an overview is provided on the present status, common imaging features, pathogenesis, clinical manifestations and treatment of cerebral small vessel disease. DOI: 10.3969/j.issn.1672-6731.2015.02.003

  16. Gamma knife radiosurgery for cerebral arteriovenous malformations.

    Science.gov (United States)

    Kemeny, A A; Radatz, M W R; Rowe, J G; Walton, L; Hampshire, A

    2004-01-01

    Since its introduction, gamma knife radiosurgery has become an important treatment modality for cerebral arteriovenous malformations. This paper is a brief overview of the technique used, of the clinical results achieved and of the experience gained in Sheffield.

  17. Cerebral cysticercosis in a cat : clinical communication

    Directory of Open Access Journals (Sweden)

    E.V. Schwan

    2002-07-01

    Full Text Available The metacestode of Taenia solium, Cysticercus cellulosae, was recovered from the brain of a cat showing central nervous clinical signs ante mortem. This is the first record of cerebral cysticercosis in a cat in South Africa.

  18. Genetics Home Reference: hereditary cerebral amyloid angiopathy

    Science.gov (United States)

    ... prognosis of a genetic condition? Genetic and Rare Diseases Information Center Frequency The prevalence of hereditary cerebral amyloid angiopathy is unknown. The Dutch type is the most common, with over 200 ...

  19. Inhibitory and excitatory amino acids in the cerebrospinal fluid of children with two types of cerebral palsy

    Institute of Scientific and Technical Information of China (English)

    Haibin Yuan; Li Wang; Fei Yin; Li Li; Jing Peng

    2008-01-01

    BACKGROUND: Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE: To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid (GABA) in the cerebrospinal fluid (CSF) of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING: Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsba Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS: We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS: Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at 70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES: The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamie acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS: The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group (P 0.05). CONCLUSION: Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an

  20. 急性脑梗死患者血清 PD-ECGF和 VEGF 的动态变化%Dynamic changes of platelet derived endothelial cell growth factor and vascular endothelial growth factor in the serum of patients with acute cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    张晓玲; 钱淑霞; 官俏兵; 杜瑛媛; 翟丽萍; 王琰萍; 俞晓翔

    2013-01-01

    Objective To investigate the dynamic changes of platelet derived endothelial cel growth factor (PD-ECGF) and vascular endothelial growth factor (VEGF) in the serum of patients with acute cerebral infarction (ACI). Methods Thirty four patients with acute cerebral infarction and 30 healthy subjects (control group)were enrol ed in the study. The PD-ECGF and VEGF levels were detected by ELISA in patients on d1, d3, d7 and d14 after infarction as wel as in healthy controls. According to the size of lesions the patients were classified as large lesion group (n=10), middle lesion group (n=13) and smal lesion group (n=11); according to the etiology patients were classified as large-artery atherosclerosis group (LAA, n=15), smal -artery occlu-sion (SAO, n=10) group and cardioembolism (CE, n=9) group. Then the correlation between serum PD-ECGF,VEGF levels and infarct size, etiology were analyzed. Results Serum PD-ECGF and VEGF levels were significantly increased in patients with ACI at al time points compared with healthy controls (P<0.05). The levels of PD-ECGF in serum reached peak value after 3d, and VEGF reached peak value after 7d, and they remained high levels at d14 after stroke. PD-ECGF and VEGF showed dramatic in-crease in serum of large lesion group and LAA group (P<0.05). Conclusion The contents of serum PD-ECGF and VEGF in-crease dramatically in patients with acute cerebral infarction, and have correlation with infarct volume and etiology. The results in-dicate that PD-ECGF and VEGF may be involved in the pathophysiology of acute cerebral infarction.%  目的探讨急性脑梗死患者血清血小板衍生内皮细胞生长因子(PD-ECGF)和血管内皮细胞生长因子(VEGF)的动态变化并分析与梗死灶大小、梗死病因类型的相关性.方法采用双抗体夹心酶联免疫吸附法(ELISA)动态测定34例急性脑梗死患者在发病后第1、3、7、14天时血清 PD-ECGF 和 VEGF 的浓度,对照组为30例本院健康体检者.