Sample records for cerebral malaria heme

  1. Cerebral malaria and the hemolysis/methemoglobin/heme hypothesis: shedding new light on an old disease. (United States)

    Pamplona, Ana; Hanscheid, Thomas; Epiphanio, Sabrina; Mota, Maria M; Vigário, Ana M


    Malaria causes more than 1 million deaths every year with cerebral malaria (CM) being a major cause of death in Sub-Saharan African children. The nature of the malaria-associated pathogenesis is complex and multi-factorial. A unified hypothesis involving sequestration of infected red blood cells, systemic host inflammatory response and hemostasis dysfunction has been proposed to explain the genesis of CM. In this review, we discuss the role of hemolysis, methemoglobin and free heme in CM, brought to light by our recent studies in mice as well as by other studies in humans.

  2. Heme oxygenase-1 and carbon monoxide suppress the pathogenesis of experimental cerebral malaria. (United States)

    Pamplona, Ana; Ferreira, Ana; Balla, József; Jeney, Viktória; Balla, György; Epiphanio, Sabrina; Chora, Angelo; Rodrigues, Cristina D; Gregoire, Isabel Pombo; Cunha-Rodrigues, Margarida; Portugal, Silvia; Soares, Miguel P; Mota, Maria M


    Cerebral malaria claims more than 1 million lives per year. We report that heme oxygenase-1 (HO-1, encoded by Hmox1) prevents the development of experimental cerebral malaria (ECM). BALB/c mice infected with Plasmodium berghei ANKA upregulated HO-1 expression and activity and did not develop ECM. Deletion of Hmox1 and inhibition of HO activity increased ECM incidence to 83% and 78%, respectively. HO-1 upregulation was lower in infected C57BL/6 compared to BALB/c mice, and all infected C57BL/6 mice developed ECM (100% incidence). Pharmacological induction of HO-1 and exposure to the end-product of HO-1 activity, carbon monoxide (CO), reduced ECM incidence in C57BL/6 mice to 10% and 0%, respectively. Whereas neither HO-1 nor CO affected parasitemia, both prevented blood-brain barrier (BBB) disruption, brain microvasculature congestion and neuroinflammation, including CD8(+) T-cell brain sequestration. These effects were mediated by the binding of CO to hemoglobin, preventing hemoglobin oxidation and the generation of free heme, a molecule that triggers ECM pathogenesis.

  3. Cerebral malaria Malaria cerebral

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    Silvia Blair Trujillo


    Full Text Available 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. 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.

  4. [Physiopathology of cerebral malaria]. (United States)

    Ringwald, P


    Physiopathology of severe malaria is extremely complex and misappreciated. Sequestration of parasited red cells and role of cytokines are now accepted but we still have to discover why only a few people develop a severe malaria. A better knowledge of that physiopathology would allow the conception of new therapeutic strategies to reduce malaria mortality.

  5. Cerebral malaria: gamma-interferon redux

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    Nicholas H Hunt


    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.

  6. Potential Serological Biomarkers of Cerebral Malaria

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    Naomi W. Lucchi


    Full Text Available Biomarkers have been used to diagnose and prognosticate the progress and outcome of many chronic diseases such as neoplastic and non communicable diseases. However, only recently did the field of malaria research move in the direction of actively identifying biomarkers that can accurately discriminate the severe forms of malaria. Malaria continues to be a deadly disease, killing close to a million people (mostly children every year. One life-threatening complication of malaria is cerebral malaria (CM. Studies carried out in Africa have demonstrated that even with the best treatment, as high as 15–30% of CM patients die and about 10–24% of CM survivors suffer short-or long-term neurological impairment. The transition from mild malaria to CM can be sudden and requires immediate intervention. Currently, there is no biological test available to confirm the diagnosis of CM and its complications. It is hoped that development of biomarkers to identify CM patients and potential risk for adverse outcomes would greatly enhance better intervention and clinical management to improve the outcomes. We review here what is currently known regarding biomarkers for CM outcomes.

  7. A case of cerebral malaria and dengue concurrent infection

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    Anwar Alam; Md Dm


    Cerebral malaria and dengue are the common infections which cause higher mortality and morbidities in every part of the world especially in India. Concurrent infection of cerebral malaria and dengue is rare entity due to different habitat of vectors and it was reported rarely from Southeast Asia. In this case report, the authors reported a case of concurrent cerebral malaria and dengue which was recovered after eight days of admission with increase in morbidity.

  8. Cerebral malaria: insight into pathogenesis, complications and molecular biomarkers (United States)

    Yusuf, Farah Hafiz; Hafiz, Muhammad Yusuf; Shoaib, Maria; Ahmed, Syed Ahsanuddin


    Cerebral malaria is a medical emergency. All patients with Plasmodium falciparum malaria with neurologic manifestations of any degree should be urgently treated as cases of cerebral malaria. Pathogenesis of cerebral malaria is due to damaged vascular endothelium by parasite sequestration, inflammatory cytokine production and vascular leakage, which result in brain hypoxia, as indicated by increased lactate and alanine concentrations. The levels of the biomarkers’ histidine-rich protein II, angiopoietin-Tie-2 system and plasma osteoprotegrin serve as diagnostic and prognostic markers. Brain imaging may show neuropathology around the caudate and putamen. Mortality is high and patients who survive sustain brain injury which manifests as long-term neurocognitive impairments. PMID:28203097

  9. Advances in the management of cerebral malaria in adults

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    Mishra, Saroj K; Wiese, Lothar


    PURPOSE OF REVIEW: Cerebral malaria continues to be a substantial cause of death and disability worldwide. Although many studies deal with cerebral malaria in children, only very few pertain to adults. Presence of multiorgan failure makes the prognosis poor. Various mechanisms in the pathogenesis...... of cerebral malaria and the role of adjuvant therapy will be discussed. RECENT FINDINGS: Artemisinin-based therapies have improved antiparasitic treatment, but in-hospital mortality still remains high, as do neurological sequelae. Several recent studies have given new insights in the pathophysiology...... of cerebral malaria particularly the role of immune mechanisms in disease progression. Recent findings have identified several potential candidates for adjuvant neuroprotective treatment. Recombinant human erythropoietin has shown beneficial effect in experimental cerebral malaria and will soon enter...

  10. Ophthalmologic identification of cerebral malaria in adults

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    Pedrosa, Catarina Areias


    Full Text Available Objective: To report the clinical presentation of malarial retinopathy in an adult, emphasizing the importance of this diagnosis for the clinical suspicion and prognosis of cerebral malaria. Methods: A 39-year-old caucasian man presented with hemolytic anemia, thrombocytopenia, acidemia and acute renal failure, developing severe encephalopathy. The diagnosis of malaria was done and after systemic stabilization, the patient noticed a central scotoma in the left eye. Ophthalmological examination revealed retinal features of malarial retinopathy. Results: At one-month follow-up, the patient had improved his systemic condition and the left eye scotoma had disappeared. Visual acuity was 20/20 in both eyes and on examination almost all lesions had regressed. Conclusion: Malarial retinopathy is a diagnostic factor and a prognosis indicator of severe infection, usually with brain involvement. The knowledge of the ophthalmological features associated with severe malaria, which is more frequent in children but can also occur in adults, becomes imperative in order to reduce the risk of neurologic sequelae and associated mortality.

  11. Neuroleptic malignant syndrome masked by cerebral malaria. (United States)

    Rajesh, Kumar Muniandy; Sinnathamby, Vellan; Sakthi, Arul N


    A 38-year-old man with an underlying psychiatric illness presented with altered sensorium and abnormal behaviour. He was febrile at 38°C and weak looking; otherwise no other abnormalities were detected. A blood film conducted for malarial parasite (BFMP) revealed Plasmodium falciparum; hence a diagnosis of cerebral malaria was made. He was treated with antimalarial drugs for 2 days prior to being transferred out to the ward following clinical improvement. He subsequently developed episodes of stupor and refusal of feeding. Following an evaluation by the psychiatrist, a diagnosis of catatonic schizophrenia was made and he was started on oral sulpiride and benhexol. Unfortunately, he developed high-grade fever at 40°C with muscle rigidity and fasciculation. The diagnosis of neuroleptic malignant syndrome (NMS) was clinched and the antipsychotics were discontinued. However he succumbed to NMS several days later due to multiorgan failure.

  12. Malaria parasite-synthesized heme is essential in the mosquito and liver stages and complements host heme in the blood stages of infection.

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    Viswanathan Arun Nagaraj

    Full Text Available Heme metabolism is central to malaria parasite biology. The parasite acquires heme from host hemoglobin in the intraerythrocytic stages and stores it as hemozoin to prevent free heme toxicity. The parasite can also synthesize heme de novo, and all the enzymes in the pathway are characterized. To study the role of the dual heme sources in malaria parasite growth and development, we knocked out the first enzyme, δ-aminolevulinate synthase (ALAS, and the last enzyme, ferrochelatase (FC, in the heme-biosynthetic pathway of Plasmodium berghei (Pb. The wild-type and knockout (KO parasites had similar intraerythrocytic growth patterns in mice. We carried out in vitro radiolabeling of heme in Pb-infected mouse reticulocytes and Plasmodium falciparum-infected human RBCs using [4-(14C] aminolevulinic acid (ALA. We found that the parasites incorporated both host hemoglobin-heme and parasite-synthesized heme into hemozoin and mitochondrial cytochromes. The similar fates of the two heme sources suggest that they may serve as backup mechanisms to provide heme in the intraerythrocytic stages. Nevertheless, the de novo pathway is absolutely essential for parasite development in the mosquito and liver stages. PbKO parasites formed drastically reduced oocysts and did not form sporozoites in the salivary glands. Oocyst production in PbALASKO parasites recovered when mosquitoes received an ALA supplement. PbALASKO sporozoites could infect mice only when the mice received an ALA supplement. Our results indicate the potential for new therapeutic interventions targeting the heme-biosynthetic pathway in the parasite during the mosquito and liver stages.

  13. Lactate transport and receptor actions in cerebral malaria

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    Mariga, Shelton T; Kolko, Miriam; Gjedde, Albert


    Cerebral malaria (CM), caused by Plasmodium falciparum infection, is a prevalent neurological disorder in the tropics. Most of the patients are children, typically with intractable seizures and high mortality. Current treatment is unsatisfactory. Understanding the pathogenesis of CM is required...... in order to identify therapeutic targets. Here, we argue that cerebral energy metabolic defects are probable etiological factors in CM pathogenesis, because malaria parasites consume large amounts of glucose metabolized mostly to lactate. Monocarboxylate transporters (MCTs) mediate facilitated transfer...

  14. Evoked potentials in pediatric cerebral malaria

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    Minal Bhanushali


    Full Text Available Cortical evoked potentials (EP provide localized data regarding brain function and may offer prognostic information and insights into the pathologic mechanisms of malariamediated cerebral injury. As part of a prospective cohort study, we obtained somatosensory evoked potentials (SSEPs and brainstem auditory EPs (AEPs within 24 hours of admission on 27 consecutive children admitted with cerebral malaria (CM. Children underwent follow-up for 12 months to determine if they had any long term neurologic sequelae. EPs were obtained in 27 pediatric CM admissions. Two children died. Among survivors followed an average of 514 days, 7/25 (28.0% had at least one adverse neurologic outcome. Only a single subject had absent cortical EPs on admission and this child had a good neurologic outcome. Among pediatric CM survivors, cortical EPs are generally intact and do not predict adverse neurologic outcomes. Further study is needed to determine if alterations in cortical EPs can be used to predict a fatal outcome in CM.

  15. Evaluating experimental cerebral malaria using oxidative stress indicator OKD48 mice. (United States)

    Imai, Takashi; Iwawaki, Takao; Akai, Ryoko; Suzue, Kazutomo; Hirai, Makoto; Taniguchi, Tomoyo; Okada, Hiroko; Hisaeda, Hajime


    Cerebral malaria is a fatal complication of malaria. Conventional methods for evaluating experimental cerebral malaria have several drawbacks. Therefore, we aimed to develop an easy-to-use method for evaluating experimental cerebral malaria using OKD48 (Keap1-dependent Oxidative stress Detector, No-48-luciferase) mice to evaluate oxidative stress. OKD48 mice infected with Plasmodium berghei ANKA strain (PbA) suffered from experimental cerebral malaria and oxidative stress was successfully detected in the brains of living OKD48 mice developing experimental cerebral malaria. Oxidative stress in the brain was dependent on the development of experimental cerebral malaria, as prevention of experimental cerebral malaria did not elicit oxidative stress. We provide a novel evaluation method for experimental cerebral malaria using oxidative stress indicator OKD48 mice.

  16. Retinal pathology of pediatric cerebral malaria in Malawi.

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    Valerie A White

    Full Text Available INTRODUCTION: The causes of coma and death in cerebral malaria remain unknown. Malarial retinopathy has been identified as an important clinical sign in the diagnosis and prognosis of cerebral malaria. As part of a larger autopsy study to determine causes of death in children with coma presenting to hospital in Blantyre, Malawi, who were fully evaluated clinically prior to death, we examined the histopathology of eyes of patients who died and underwent autopsy. METHODOLOGY/PRINCIPAL FINDINGS: Children with coma were admitted to the pediatric research ward, classified according to clinical definitions as having cerebral malaria or another cause of coma, evaluated and treated. The eyes were examined by direct and indirect ophthalmoscopy. If a child died and permission was given, a standardized autopsy was carried out. The patient was then assigned an actual cause of death according to the autopsy findings. The eyes were examined pathologically for hemorrhages, cystoid macular edema, parasite sequestration and thrombi. They were stained immunohistochemically for fibrin and CD61 to identify the components of thrombi, beta-amyloid precursor protein to detect axonal damage, for fibrinogen to identify vascular leakage and for glial fibrillary acidic protein to detect gliosis. Sixty-four eyes from 64 patients were examined: 35 with cerebral malaria and 29 with comas of other causes. Cerebral malaria was distinguished by sequestration of parasitized erythrocytes, the presence and severity of retinal hemorrhages, the presence of cystoid macular edema, the occurrence and number of fibrin-platelet thrombi, the presence and amount of axonal damage and vascular leakage. CONCLUSIONS/SIGNIFICANCE: We found significant differences in retinal histopathology between patients who died of cerebral malaria and those with other diagnoses. These histopathological findings offer insights into the etiology of malarial retinopathy and provide a pathological basis for

  17. In silico multiple-targets identification for heme detoxification in the human malaria parasite Plasmodium falciparum. (United States)

    Phaiphinit, Suthat; Pattaradilokrat, Sittiporn; Lursinsap, Chidchanok; Plaimas, Kitiporn


    Detoxification of hemoglobin byproducts or free heme is an essential step and considered potential targets for anti-malaria drug development. However, most of anti-malaria drugs are no longer effective due to the emergence and spread of the drug resistant malaria parasites. Therefore, it is an urgent need to identify potential new targets and even for target combinations for effective malaria drug design. In this work, we reconstructed the metabolic networks of Plasmodium falciparum and human red blood cells for the simulation of steady mass and flux flows of the parasite's metabolites under the blood environment by flux balance analysis (FBA). The integrated model, namely iPF-RBC-713, was then adjusted into two stage-specific metabolic models, which first was for the pathological stage metabolic model of the parasite when invaded the red blood cell without any treatment and second was for the treatment stage of the parasite when a drug acted by inhibiting the hemozoin formation and caused high production rate of heme toxicity. The process of identifying target combinations consisted of two main steps. Firstly, the optimal fluxes of reactions in both the pathological and treatment stages were computed and compared to determine the change of fluxes. Corresponding enzymes of the reactions with zero fluxes in the treatment stage but non-zero fluxes in the pathological stage were predicted as a preliminary list of potential targets in inhibiting heme detoxification. Secondly, the combinations of all possible targets listed in the first step were examined to search for the best promising target combinations resulting in more effective inhibition of the detoxification to kill the malaria parasites. Finally, twenty-three enzymes were identified as a preliminary list of candidate targets which mostly were in pyruvate metabolism and citrate cycle. The optimal set of multiple targets for blocking the detoxification was a set of heme ligase, adenosine transporter, myo

  18. Neuroimaging findings in children with retinopathy-confirmed cerebral malaria

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    Potchen, Michael J. [Michigan State University, Department of Radiology, 184 Radiology Building, East Lansing, MI 48824-1303 (United States)], E-mail:; Birbeck, Gretchen L. [Michigan State University, International Neurologic and Psychiatric Epidemiology Program, 324 West Fee Hall, East Lansing, MI 48824 (United States)], E-mail:; DeMarco, J. Kevin [Michigan State University, Department of Radiology, 184 Radiology Building, East Lansing, MI 48824-1303 (United States)], E-mail:; Kampondeni, Sam D. [University of Malawi, Department of Radiology, Queen Elizabeth Central Hospital, Blantyre (Malawi)], E-mail:; Beare, Nicholas [St. Paul' s Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP (United Kingdom)], E-mail:; Molyneux, Malcolm E. [Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine (Malawi); School of Tropical Medicine, University of Liverpool, Liverpool (United Kingdom)], E-mail:; Taylor, Terrie E. [Michigan State University, College of Osteopathic Medicine, B309-B West Fee Hall, East Lansing, MI 48824 (United States); University of Malawi, College of Medicine, Blantyre Malaria Project, Blantyre (Malawi)], E-mail:


    Purpose: To describe brain CT findings in retinopathy-confirmed, paediatric cerebral malaria. Materials and methods: In this outcomes study of paediatric cerebral malaria, a subset of children with protracted coma during initial presentation was scanned acutely. Survivors experiencing adverse neurological outcomes also underwent a head CT. All children had ophthalmological examination to confirm the presence of the retinopathy specific for cerebral malaria. Independent interpretation of CT images was provided by two neuroradiologists. Results: Acute brain CT findings in three children included diffuse oedema with obstructive hydrocephalus (2), acute cerebral infarctions in multiple large vessel distributions with secondary oedema and herniation (1), and oedema of thalamic grey matter (1). One child who was reportedly normal prior to admission had parenchymal atrophy suggestive of pre-existing CNS injury. Among 56 survivors (9-84 months old), 15 had adverse neurologic outcomes-11/15 had a follow-up head CT, 3/15 died and 1/15 refused CT. Follow-up head CTs obtained 7-18 months after the acute infection revealed focal and multifocal lobar atrophy correlating to regions affected by focal seizures during the acute infection (5/11). Other findings were communicating hydrocephalus (2/11), vermian atrophy (1/11) and normal studies (3/11). Conclusions: The identification of pre-existing imaging abnormalities in acute cerebral malaria suggests that population-based studies are required to establish the rate and nature of incidental imaging abnormalities in Malawi. Children with focal seizures during acute cerebral malaria developed focal cortical atrophy in these regions at follow-up. Longitudinal studies are needed to further elucidate mechanisms of CNS injury and death in this common fatal disease.

  19. The systemic pathology of cerebral malaria in African children

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    Danny Arnold Milner


    Full Text Available Pediatric cerebral malaria carries a high mortality rate in sub-Saharan Africa. We present our systematic analysis of the descriptive and quantitative histopathology of all organs sampled from a series of 103 autopsies performed between 1996 and 2010 in Blantyre, Malawi on pediatric cerebral malaria patients and control patients (without coma, or without malaria infection who were clinically well characterized prior to death. We found brain swelling in all cerebral malaria patients and the majority of controls. The histopathology in patients with sequestration of parasites in the brain demonstrated two patterns: a the classic appearance (i.e., ring hemorrhages, dense sequestration, and extra-erythrocytic pigment which was associated with evidence of systemic activation of coagulation and b the sequestration only appearance associated with shorter duration of illness and higher total burden of parasites in all organs including the spleen. Sequestration of parasites was most intense in the gastrointestinal tract in all parasitemic patients (those with cerebral malarial and those without.

  20. Cloning, expression and functional characterization of heme detoxification protein (HDP) from the rodent malaria parasite Plasmodium vinckei. (United States)

    Soni, Awakash; Goyal, Manish; Prakash, Kirtika; Bhardwaj, Jyoti; Siddiqui, Arif Jamal; Puri, Sunil K


    Malaria parasite resides within the host red blood cells, where it degrades vast amount of haemoglobin. During haemoglobin degradation, toxic free heme is liberated which subsequently gets converted into hemozoin. This process is facilitated by action of various proteins viz. heme detoxification protein (HDP), and histidine rich proteins II and III (HRP II & III). Out of these, HDP is the most potent in hemozoin formation and plays indispensible role for parasite survival. Despite this, the detailed study of HDP from rodent and simian parasite has not been performed till date. Here, we have cloned and sequenced hdp gene from different malaria parasites Plasmodium vinckei, Plasmodium yoelii, Plasmodium knowlesi, and Plasmodium cynomolgi. Furthermore, HDP from P. vinckei (PvHDP) was over-expressed and purified for detailed characterization. The PvHDP is cytosolic, expressed throughout the intra erythrocytic stages and its expression is higher in late trophozoite and schizont stages of parasite. The PvHDP interacts with free heme (KD=89 nM) and efficiently converts heme into hemozoin in a time and concentration dependent manner. Moreover, PvHDP showed activity in acidic pH and over a broad range of temperature. Histidine modification of PvHDP using DEPC showed reduction in heme binding and hemozoin formation, thus emphasizing the importance of histidine residues in heme binding and subsequent hemozoin production. Furthermore, applicability of PvHDP to screen anti-plasmodial agents (targeting heme to hemozoin conversion) was also determined using chloroquine, and mefloquine as reference antimalarials. Results showed that these drugs inhibit heme polymerization effectively in a concentration dependent manner. In conclusion, our study identified and biochemically characterized HDP from rodent malaria parasite P. vinckei and this will help to develop a high throughput assay to evaluate new antimalarials targeting hemozoin pathway.

  1. Pentoxifylline as an adjunct therapy in children with cerebral malaria

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    Kokwaro Gilbert


    Full Text Available Abstract Background Pentoxifylline (PTX affects many processes that may contribute to the pathogenesis of severe malaria and it has been shown to reduce the duration of coma in children with cerebral malaria. This pilot study was performed to assess pharmacokinetics, safety and efficacy of PTX in African children with cerebral malaria. Methods Ten children admitted to the high dependency unit of the Kilifi District Hospital in Kenya with cerebral malaria (Blantyre coma score of 2 or less received quinine plus a continuous infusion of 10 mg/kg/24 hours PTX for 72 hours. Five children were recruited as controls and received normal saline instead of PTX. Plasma samples were taken for PTX and tumour necrosis factor (TNF levels. Blantyre Coma Score, parasitemia, hematology and vital signs were assessed 4 hourly. Results One child (20% in the control group died, compared to four children (40% in the PTX group. This difference was not significant (p = 0.60. Laboratory parameters and clinical data were comparable between groups. TNF levels were lower in children receiving PTX. Conclusions The small sample size does not permit definitive conclusions, but the mortality rate was unexpectedly high in the PTX group.

  2. Macrophage preconditioning with synthetic malaria pigment reduces cytokine production via heme iron-dependent oxidative stress. (United States)

    Taramelli, D; Recalcati, S; Basilico, N; Olliaro, P; Cairo, G


    Hemozoin (malaria pigment), a polymer of hematin (ferri-protoporphyrin IX) derived from hemoglobin ingested by intraerythrocytic plasmodia, modulates cytokine production by phagocytes. Mouse peritoneal macrophages (PM) fed with synthetic beta-hematin (BH), structurally identical to native hemozoin, no longer produce tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) in response to lipopolysaccharide (LPS). Impairment of NO synthesis is due to inhibition of inducible nitric oxide synthase (iNOS) production. BH-mediated inhibition of PM functions cannot be ascribed to iron release from BH because neither prevention by iron chelators nor down-regulation of iron-regulatory protein activity was detected. Inhibition appears to be related to pigment-induced oxidative stress because (a) thiol compounds partially restored PM functions, (b) heme oxygenase (HO-1) and catalase mRNA levels were up-regulated, and (c) free radicals production increased in BH-treated cells. The antioxidant defenses of the cells determine the response to BH: microglia cells, which show a lower extent of induction of HO-1 and catalase mRNAs and lower accumulation of oxygen radicals, are less sensitive to the inhibitory effect of BH on cytokine production. Results indicate that BH is resistant to degradation by HO-1 and that heme-iron mediated oxidative stress may contribute to malaria-induced immunosuppression. This study may help correlate the different clinical manifestations of malaria, ranging from uncomplicated to severe disease, with dysregulation of phagocyte functions and promote better therapeutic strategies to counteract the effects of hemozoin accumulation.

  3. Whole blood angiopoietin-1 and -2 levels discriminate cerebral and severe (non-cerebral malaria from uncomplicated malaria

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    Tangpukdee Noppadon


    Full Text Available Abstract Background Severe and cerebral malaria are associated with endothelial activation. Angiopoietin-1 (ANG-1 and angiopoietin-2 (ANG-2 are major regulators of endothelial activation and integrity. The aim of this study was to investigate the clinical utility of whole blood angiopoietin (ANG levels as biomarkers of disease severity in Plasmodium falciparum malaria. Methods The utility of whole blood ANG levels was examined in Thai patients to distinguish cerebral (CM; n = 87 and severe (non-cerebral malaria (SM; n = 36 from uncomplicated malaria (UM; n = 70. Comparative statistics are reported using a non-parametric univariate analysis (Kruskal-Wallis test or Chi-squared test, as appropriate. Multivariate binary logistic regression was used to examine differences in whole blood protein levels between groups (UM, SM, CM, adjusting for differences due to ethnicity, age, parasitaemia and sex. Receiver operating characteristic curve analysis was used to assess the diagnostic accuracy of the ANGs in their ability to distinguish between UM, SM and CM. Cumulative organ injury scores were obtained for patients with severe disease based on the presence of acute renal failure, jaundice, severe anaemia, circulatory collapse or coma. Results ANG-1 and ANG-2 were readily detectable in whole blood. Compared to UM there were significant decreases in ANG-1 (p Conclusions These results suggest that whole blood ANG-1/2 levels are promising clinically informative biomarkers of disease severity in malarial syndromes.

  4. Loss of Toll-like receptor 7 alters cytokine production and protects against experimental cerebral malaria


    Baccarella, Alyssa; Huang, Brian W; Fontana, Mary F.; Kim, Charles C


    Background Malaria, caused by Plasmodium sp. parasites, is a leading cause of global morbidity and mortality. Cerebral malaria, characterized by neurological symptoms, is a life-threatening complication of malaria affecting over 500,000 young children in Africa every year. Because of the prevalence and severity of cerebral malaria, a better understanding of the underlying molecular mechanisms of its pathology is desirable and could inform future development of therapeutics. This study sought ...

  5. Activated Neutrophils Are Associated with Pediatric Cerebral Malaria Vasculopathy in Malawian Children (United States)

    Feintuch, Catherine Manix; Saidi, Alex; Seydel, Karl; Chen, Grace; Goldman-Yassen, Adam; Mita-Mendoza, Neida K.; Kim, Ryung S.; Frenette, Paul S.; Taylor, Terrie


    ABSTRACT Most patients with cerebral malaria (CM) sustain cerebral microvascular sequestration of Plasmodium falciparum-infected red blood cells (iRBCs). Although many young children are infected with P. falciparum, CM remains a rare outcome; thus, we hypothesized that specific host conditions facilitate iRBC cerebral sequestration. To identify these host factors, we compared the peripheral whole-blood transcriptomes of Malawian children with iRBC cerebral sequestration, identified as malarial-retinopathy-positive CM (Ret+CM), to the transcriptomes of children with CM and no cerebral iRBC sequestration, defined as malarial-retinopathy-negative CM (Ret-CM). Ret+CM was associated with upregulation of 103 gene set pathways, including cytokine, blood coagulation, and extracellular matrix (ECM) pathways (P < 0.01; false-discovery rate [FDR] of <0.05). Neutrophil transcripts were the most highly upregulated individual transcripts in Ret+CM patients. Activated neutrophils can modulate diverse host processes, including the ECM, inflammation, and platelet biology to potentially facilitate parasite sequestration. Therefore, we compared plasma neutrophil proteins and neutrophil chemotaxis between Ret+CM and Ret-CM patients. Plasma levels of human neutrophil elastase, myeloperoxidase, and proteinase 3, but not lactoferrin or lipocalin, were elevated in Ret+CM patients, and neutrophil chemotaxis was impaired, possibly related to increased plasma heme. Neutrophils were rarely seen in CM brain microvasculature autopsy samples, and no neutrophil extracellular traps were found, suggesting that a putative neutrophil effect on endothelial cell biology results from neutrophil soluble factors rather than direct neutrophil cellular tissue effects. Meanwhile, children with Ret-CM had lower levels of inflammation, higher levels of alpha interferon, and upregulation of Toll-like receptor pathways and other host transcriptional pathways, which may represent responses that do not favor

  6. Breaking down brain barrier breaches in cerebral malaria

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    Petersen, Jens E V; Lavstsen, Thomas; Craig, Alister


    Recent findings have linked brain swelling to death in cerebral malaria (CM). These observations have prompted a number of investigations into the mechanisms of this pathology with the goal of identifying potential therapeutic targets. In this issue of the JCI, Gallego-Delgado and colleagues...... erythrocyte sequestration in the brain as the major driver of disease. While this work provides potential therapeutic avenues for CM, it leaves a number of questions unanswered....

  7. Requirement for Tumor Necrosis Factor Receptor 2 Expression on Vascular Cells To Induce Experimental Cerebral Malaria


    Stoelcker, Benjamin; Hehlgans, Thomas; Weigl, Karin; Bluethmann, Horst; Grau, Georges E.; Männel, Daniela N


    Using tumor necrosis factor receptor type 2 (TNFR2)-deficient mice and generating bone marrow chimeras which express TNFR2 on either hematopoietic or nonhematopoietic cells, we demonstrated the requirement for TNFR2 expression on tissue cells to induce lethal cerebral malaria. Thus, TNFR2 on the brain vasculature mediates tumor necrosis factor-induced neurovascular lesions in experimental cerebral malaria.

  8. Filaria-induced IL-10 suppresses murine cerebral malaria. (United States)

    Specht, Sabine; Ruiz, Daniel Fernández; Dubben, Bettina; Deininger, Susanne; Hoerauf, Achim


    Filarial nematodes achieve long survival in their hosts due to their capacity to modulate immune responses. Therefore, immunomodulation by filarial nematodes may alter responses to concomitant infections such as malaria. Cerebral malaria (CM), a severe complication of Plasmodium falciparum infections, is triggered as a consequence of the immune response developed against malaria parasites. The question arises whether prior infection with helminth parasites is beneficial against CM. In the present work a murine model for subsequent has been used to assess this hypothesis. C57BL/6 mice were infected with the rodent filarial parasite Litomosoides sigmodontis and the murine model parasite for CM, Plasmodium berghei ANKA. Previously filaria-infected C57BL/6 mice showed significantly reduced CM rates. CD8(+) T cell recruitment to the brain, a hallmark for CM development, was reduced in protected mice. Furthermore, in contrast to P. berghei single-infected animals, filaria-infected mice had significantly higher levels of circulating IL-10. The requirement for IL-10 in CM protection was demonstrated by the lack of protection in IL-10 KO mice. This suggests that the anti-inflammatory IL-10 elicited by filarial nematodes is able to suppress the overwhelming inflammatory reaction otherwise triggered against malaria parasites in C57BL/6 mice, preventing full progress to CM.

  9. Investigation of Hydrogen Sulfide Gas as a Treatment against P. falciparum, Murine Cerebral Malaria, and the Importance of Thiolation State in the Development of Cerebral Malaria

    DEFF Research Database (Denmark)

    Dellavalle, Brian; Staalsoe, Trine; Kurtzhals, Jørgen Anders;


    Cerebral malaria (CM) is a potentially fatal cerebrovascular disease of complex pathogenesis caused by Plasmodium falciparum. Hydrogen sulfide (HS) is a physiological gas, similar to nitric oxide and carbon monoxide, involved in cellular metabolism, vascular tension, inflammation, and cell death...

  10. Endothelin-1 Mediates Brain Microvascular Dysfunction Leading to Long-Term Cognitive Impairment in a Model of Experimental Cerebral Malaria.

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    Brandi D Freeman


    Full Text Available Plasmodium falciparum infection causes a wide spectrum of diseases, including cerebral malaria, a potentially life-threatening encephalopathy. Vasculopathy is thought to contribute to cerebral malaria pathogenesis. The vasoactive compound endothelin-1, a key participant in many inflammatory processes, likely mediates vascular and cognitive dysfunctions in cerebral malaria. We previously demonstrated that C57BL6 mice infected with P. berghei ANKA, our fatal experimental cerebral malaria model, sustained memory loss. Herein, we demonstrate that an endothelin type A receptor (ETA antagonist prevented experimental cerebral malaria-induced neurocognitive impairments and improved survival. ETA antagonism prevented blood-brain barrier disruption and cerebral vasoconstriction during experimental cerebral malaria, and reduced brain endothelial activation, diminishing brain microvascular congestion. Furthermore, exogenous endothelin-1 administration to P. berghei NK65-infected mice, a model generally regarded as a non-cerebral malaria negative control for P. berghei ANKA infection, led to experimental cerebral malaria-like memory deficits. Our data indicate that endothelin-1 is critical in the development of cerebrovascular and cognitive impairments with experimental cerebral malaria. This vasoactive peptide may thus serve as a potential target for adjunctive therapy in the management of cerebral malaria.

  11. Characteristic abnormalities in cerebrospinal fluid biochemistry in children with cerebral malaria compared to viral encephalitis

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    Atmakuri RM


    Full Text Available Abstract Background In developing countries where Plasmodium falciparum malaria is endemic, viral encephalitis and cerebral malaria are found in the same population, and parasitemia with Plasmodium falciparum is common in asymptomatic children. The objective of this study was to investigate the cerebrospinal fluid (CSF biochemistry in children with cerebral malaria compared to those with presumed viral encephalitis. Methods We studied the following CSF parameters: cell count, glucose, protein, lactic dehydrogenase (LDH and adenosine deaminase (ADA levels, in children with cerebral malaria, with presumed viral encephalitis, and in control subjects who had a lumbar puncture after a febrile convulsion with postictal coma. Results We recruited 12 children with cerebral malaria, 14 children with presumed viral encephalitis and 20 controls prospectively, over 2 years in the Government General Hospital in Kakinada, India. Patients with cerebral malaria had significantly lower CSF glucose, and higher protein, LDH, CSF/blood LDH ratio and CSF ADA levels but a lower CSF/serum ADA ratio compared to controls (p Conclusion CSF/serum ADA ratio and CSF glucose levels were the best discriminators of cerebral malaria from presumed viral encephalitis in our study. Further studies are needed to explore their usefulness in epidemiological studies.

  12. Proteomic Studies on Human and Experimental Cerebral Malaria

    KAUST Repository

    Moussa, Ehab


    Cerebral malaria (CM) is a severe neurological complication of malaria infection that results from interrelated pathologies. Despite extensive research efforts, the mechanism of the disease is not completely understood. Clinical studies, postmortem analysis, and animal models have been the main research arenas in CM. In this thesis, shotgun proteomics approach was used to further understand the pathology of human and experimental CM. The mechanism by which CM turns fatal is yet to be identified. A clinical proteomics study was conducted on pooled plasma samples from children with reversible or fatal CM from the Gambia. The results show that depletion of coagulation factors and increased levels of circulating proteasomes are associated with fatal pediatric CM. This data suggests that the ongoing coagulation during CM might be a disseminated intravascular coagulation state that eventually causes depletion of the coagulation factors leading to petechial hemorrhages. In addition, the mechanism(s) by which blood transfusion benefits CM in children was investigated. To that end, the concentration and multimerization pattern of von-willebrand factor, and the concentration of haptoglobin in the plasma of children with CM who received blood transfusions were measured. In addition to clinical studies, experimental cerebral malaria (ECM) in mice has been long used as a model for the disease. A shotgun proteomics workflow was optimized to identify the proteomic signature of the brain tissue of mice with ECM.Because of the utmost importance of membrane proteins in the pathology of the disease, sample fractionation and filter aided sample preparation were used to recover them. The proteomic signature of the brains of mice infected with P. berghei ANKA that developed neurological syndrome, mice infected with P. berghei NK56 that developed severe malaria but without neurological signs, and non-infected mice, were compared to identify CM specific proteins. Among the differentially

  13. Toll-like receptor polymorphisms and cerebral malaria: TLR2 Δ22 polymorphism is associated with protection from cerebral malaria in a case control study

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    Greene Jennifer A


    Full Text Available Abstract Background In malaria endemic areas, host genetics influence whether a Plasmodium falciparum-infected child develops uncomplicated or severe malaria. TLR2 has been identified as a receptor for P. falciparum-derived glycosylphosphatidylinositol (GPI, and polymorphisms within the TLR2 gene may affect disease pathogenesis. There are two common polymorphisms in the 5' un-translated region (UTR of TLR2, a 22 base pair deletion in the first unstranslated exon (Δ22, and a GT dinucleotide repeat in the second intron (GTn. Methods These polymorphisms were examined in a Ugandan case control study on children with either cerebral malaria or uncomplicated malaria. Serum cytokine levels were analysed by ELISA, according to genotype and disease status. In vitro TLR2 expression was measured according to genotype. Results Both Δ22 and GTn polymorphisms were highly frequent, but only Δ22 heterozygosity was associated with protection from cerebral malaria (OR 0.34, 95% confidence intervals 0.16, 0.73. In vitro, heterozygosity for Δ22 was associated with reduced pam3cys inducible TLR2 expression in human monocyte derived macrophages. In uncomplicated malaria patients, Δ22 homozygosity was associated with elevated serum IL-6 (p = 0.04, and long GT repeat alleles were associated with elevated TNF (p = 0.007. Conclusion Reduced inducible TLR2 expression may lead to attenuated pro-inflammatory responses, a potential mechanism of protection from cerebral malaria present in individuals heterozygous for the TLR2 Δ22 polymorphism.

  14. Breaking down brain barrier breaches in cerebral malaria. (United States)

    Petersen, Jens E V; Lavstsen, Thomas; Craig, Alister


    Recent findings have linked brain swelling to death in cerebral malaria (CM). These observations have prompted a number of investigations into the mechanisms of this pathology with the goal of identifying potential therapeutic targets. In this issue of the JCI, Gallego-Delgado and colleagues present evidence that implicates angiotensin receptors and the relocation of β-catenin to the endothelial cell nucleus in CM. This study provides a renewed focus on infected erythrocyte debris as the cause of endothelial damage and challenges previous work implicating direct effects of infected erythrocyte sequestration in the brain as the major driver of disease. While this work provides potential therapeutic avenues for CM, it leaves a number of questions unanswered.

  15. A novel endogenous antimalarial: Fe(II)-protoporphyrin IX alpha (heme) inhibits hematin polymerization to beta-hematin (malaria pigment) and kills malaria parasites. (United States)

    Monti, D; Vodopivec, B; Basilico, N; Olliaro, P; Taramelli, D


    The polymerization of hemoglobin-derived ferric-protoporphyrin IX [Fe(III)PPIX] to inert hemozoin (malaria pigment) is a crucial and unique process for intraerythrocytic plasmodia to prevent heme toxicity and thus a good target for new antimalarials. Quinoline drugs, i.e., chloroquine, and non-iron porphyrins have been shown to block polymerization by forming electronic pi-pi interactions with heme monomers. Here, we report the identification of ferrous-protoporphyrin IX [Fe(II)PPIX] as a novel endogenous anti-malarial. Fe(II)PPIX molecules, released from the proteolysis of hemoglobin, are first oxidized and then polymerized to hemozoin. We obtained Fe(II)PPIX on preparative scale by electrochemical reduction of Fe(III)PPIX, and the reaction was monitored by cyclic voltammetry. Polymerization assays at acidic pH were conducted with the resulting Fe(II)PPIX using a spectrophotometric microassay of heme polymerization adapted to anaerobic conditions and the products characterized by infrared spectroscopy. Fe(II)PPIX (a) did not polymerize and (b) produced a dose-dependent inhibition of Fe(III)PPIX polymerization (IC(50) = 0.4 molar equiv). Moreover, Fe(II)PPIX produced by chemical reduction with thiol-containing compounds gave similar results: a dose-dependent inhibition of heme polymerization was observed using either L-cysteine, N-acetylcysteine, or DL-homocysteine, but not with L-cystine. Cyclic voltammetry confirmed that the inhibition of heme polymerization was due to the Fe(II)PPIX molecules generated by the thiol-mediated reduction of Fe(III)PPIX. These results point to Fe(II)PPIX as a potential endogenous antimalarial and to Fe(III)PPIX reduction as a potential new pharmacological target.

  16. From METS to malaria: RRx-001, a multi-faceted anticancer agent with activity in cerebral malaria


    Yalcin, Ozlem; Oronsky, Bryan; Carvalho, Leonardo J. M.; Kuypers, Frans A; Scicinski, Jan; Cabrales, Pedro


    RESEARCH Open Access From METS to malaria: RRx-001, a multi-faceted anticancer agent with activity in cerebral malaria Ozlem Yalcin1,2, Bryan Oronsky3, Leonardo J. M. Carvalho4,5, Frans A. Kuypers6, Jan Scicinski3 and Pedro Cabrales1* Abstract Background: The survival of malaria parasites, under substantial haem-induced oxidative stress in the red blood cells (RBCs) is dependent on the pentose phosphate pathway (PPP). The PPP is the only source of NADPH in the RBC, ess...

  17. Cerebral Malaria; Mechanisms Of Brain Injury And Strategies For Improved Neuro-Cognitive Outcome


    Idro, Richard; Marsh, Kevin; John, Chandy C.; Newton, Charles RJ


    Cerebral malaria is the most severe neurological complication of infection with Plasmodium falciparum. With over 575,000 cases annually, children in sub-Saharan Africa are the most affected. Surviving patients have an increased risk of neurological and cognitive deficits, behavioral difficulties and epilepsy making cerebral malaria a leading cause of childhood neuro-disability in the region. The pathogenesis of neuro-cognitive sequelae is poorly understood: coma develops through multiple mech...

  18. Plasmodium vivax cerebral malaria complicated with venous sinus thrombosis in Colombia

    Institute of Scientific and Technical Information of China (English)

    Miguel A Pinzn; Juan C Pineda; Fernando Rosso; Masaru Shinchi; Fabio Bonilla-Abada


    Complicated malaria is usually due to Plasmodium falciparum. Nevertheless, Plasmodium vivax is infrequently related with life-threatening complications. Few cases have been reported of severe Plasmodium vivax infection, and most of them from Southeast Asia and India. We report the first case of cerebral malaria due to Plasmodium vivax in Latin America, complicated with sagittal sinus thrombosis and confirmed by a molecular method.

  19. Scanning electron microscopy of the neuropathology of murine cerebral malaria

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    Brenneis Christian


    Full Text Available Abstract Background The mechanisms leading to death and functional impairments due to cerebral malaria (CM are yet not fully understood. Most of the knowledge about the pathomechanisms of CM originates from studies in animal models. Though extensive histopathological studies of the murine brain during CM are existing, alterations have not been visualized by scanning electron microscopy (SEM so far. The present study investigates the neuropathological features of murine CM by applying SEM. Methods C57BL/6J mice were infected with Plasmodium berghei ANKA blood stages. When typical symptoms of CM developed perfused brains were processed for SEM or light microscopy, respectively. Results Ultrastructural hallmarks were disruption of vessel walls, parenchymal haemorrhage, leukocyte sequestration to the endothelium, and diapedesis of macrophages and lymphocytes into the Virchow-Robin space. Villous appearance of observed lymphocytes were indicative of activated state. Cerebral oedema was evidenced by enlargement of perivascular spaces. Conclusion The results of the present study corroborate the current understanding of CM pathophysiology, further support the prominent role of the local immune system in the neuropathology of CM and might expose new perspectives for further interventional studies.

  20. Detection, characterization, and screening of heme-binding molecules by mass spectrometry for malaria drug discovery

    NARCIS (Netherlands)

    Munoz-Durango, K.; Maciuk, A.; Harfouche, A.; Torijano-Gutierrez, S.; Jullian, J.C.; Quintin, J.; Spelman, K.; Mouray, E.; Grellier, P.; Figadere, B.


    Drug screening for antimalarials uses heme biocrystallization inhibition methods as an alternative to parasite cultures, but they involve complex processes and cannot detect artemisinin-like molecules. The described method detects heme-binding compounds by mass spectrometry, using dissociation of th

  1. Imaging experimental cerebral malaria in vivo: significant role of ischemic brain edema. (United States)

    Penet, Marie-France; Viola, Angèle; Confort-Gouny, Sylviane; Le Fur, Yann; Duhamel, Guillaume; Kober, Frank; Ibarrola, Danielle; Izquierdo, Marguerite; Coltel, Nicolas; Gharib, Bouchra; Grau, Georges E; Cozzone, Patrick J


    The first in vivo magnetic resonance study of experimental cerebral malaria is presented. Cerebral involvement is a lethal complication of malaria. To explore the brain of susceptible mice infected with Plasmodium berghei ANKA, multimodal magnetic resonance techniques were applied (imaging, diffusion, perfusion, angiography, spectroscopy). They reveal vascular damage including blood-brain barrier disruption and hemorrhages attributable to inflammatory processes. We provide the first in vivo demonstration for blood-brain barrier breakdown in cerebral malaria. Major edema formation as well as reduced brain perfusion was detected and is accompanied by an ischemic metabolic profile with reduction of high-energy phosphates and elevated brain lactate. In addition, angiography supplies compelling evidence for major hemodynamics dysfunction. Actually, edema further worsens ischemia by compressing cerebral arteries, which subsequently leads to a collapse of the blood flow that ultimately represents the cause of death. These findings demonstrate the coexistence of inflammatory and ischemic lesions and prove the preponderant role of edema in the fatal outcome of experimental cerebral malaria. They improve our understanding of the pathogenesis of cerebral malaria and may provide the necessary noninvasive surrogate markers for quantitative monitoring of treatment.

  2. Experimental Cerebral Malaria Spreads along the Rostral Migratory Stream (United States)

    Hoffmann, Angelika; Pfeil, Johannes; Alfonso, Julieta; Kurz, Felix T.; Sahm, Felix; Heiland, Sabine; Monyer, Hannah; Bendszus, Martin; Mueller, Ann-Kristin; Helluy, Xavier; Pham, Mirko


    It is poorly understood how progressive brain swelling in experimental cerebral malaria (ECM) evolves in space and over time, and whether mechanisms of inflammation or microvascular sequestration/obstruction dominate the underlying pathophysiology. We therefore monitored in the Plasmodium berghei ANKA-C57BL/6 murine ECM model, disease manifestation and progression clinically, assessed by the Rapid-Murine-Coma-and-Behavioral-Scale (RMCBS), and by high-resolution in vivo MRI, including sensitive assessment of early blood-brain-barrier-disruption (BBBD), brain edema and microvascular pathology. For histological correlation HE and immunohistochemical staining for microglia and neuroblasts were obtained. Our results demonstrate that BBBD and edema initiated in the olfactory bulb (OB) and spread along the rostral-migratory-stream (RMS) to the subventricular zone of the lateral ventricles, the dorsal-migratory-stream (DMS), and finally to the external capsule (EC) and brainstem (BS). Before clinical symptoms (mean RMCBS = 18.5±1) became evident, a slight, non-significant increase of quantitative T2 and ADC values was observed in OB+RMS. With clinical manifestation (mean RMCBS = 14.2±0.4), T2 and ADC values significantly increased along the OB+RMS (p = 0.049/p = 0.01). Severe ECM (mean RMCBS = 5±2.9) was defined by further spread into more posterior and deeper brain structures until reaching the BS (significant T2 elevation in DMS+EC+BS (p = 0.034)). Quantitative automated histological analyses confirmed microglial activation in areas of BBBD and edema. Activated microglia were closely associated with the RMS and neuroblasts within the RMS were severely misaligned with respect to their physiological linear migration pattern. Microvascular pathology and ischemic brain injury occurred only secondarily, after vasogenic edema formation and were both associated less with clinical severity and the temporal course of ECM. Altogether, we identified a distinct spatiotemporal


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    Gautam Lal


    Full Text Available AIM: Evaluation of Clinico - hematological profile and outcome of cerebral malaria in semi urban hospital situated in endemic area. MATERIAL AND METHODS : A cross - sectional hospital - based study was conducted from August to November, 2014 at Department of Paediatrics SRG Zanana Hospital, Jhalawar Rajasthan. Every child, except who was previously abnormal neurologically, of the age of six month to 12 years, presented with a history of fever in the last 7 days, with o r without convulsion, and/or impaired consciousness, screened for malaria by peripheral blood smear examination and rapid diagnostic test for malaria parasite. On the basis of this screening examination, these children were classified definite cerebral mal aria where the peripheral smear was positive and probable cerebral malaria where the peripheral smear was negative. If the patients presented with fever, convulsion, and/or impaired level of consciousness, they were treated with Artesunate intravenously em pirically. Patients were followed - up regularly till they regained consciousness and when, they were able to swallow, treated with oral Artisunate and single dose of Sulphadoxine and Pyrimethamine combination is also given. RESULTS: Of the3332 admissions, 8 69 (26.08% were admitted for fever. Out of these 869 febrile patients 352 patients were having other obvious clinical diagnosis for fever. In remaining 517(59.49% cases were suspected to be suffering from malaria, but all of these children who were admit ted with the diagnosis of fever, were screened for malaria and 74(08.51%were found to be positive for malaria parasite either by peripheral blood smear or rapid diagnostic test or both. Cerebral malaria developed in 37 patients. Most cases were of age gro up of 2 - 5 years, 14children had definite cerebral malaria and 9 were labelled as suspected to have probable cerebral malaria. Neurological symptoms of altered sensorium, convulsion and abnormal behaviour ranged from 35

  4. Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome. (United States)

    Matsubara, Ryuma; Aonuma, Hiroka; Kojima, Mikiko; Tahara, Michiru; Andrabi, Syed Bilal Ahmad; Sakakibara, Hitoshi; Nagamune, Kisaburo


    The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2.

  5. Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome.

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    Ryuma Matsubara

    Full Text Available The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2.

  6. Differential microRNA expression in experimental cerebral and noncerebral malaria

    DEFF Research Database (Denmark)

    El-Assaad, Fatima; Hempel, Casper; Combes, Valéry


    berghei ANKA (PbA), which causes cerebral malaria (CM), or Plasmodium berghei K173 (PbK), which causes severe malaria but without cerebral complications, termed non-CM. The differential expression profiles of selected miRNAs (let-7i, miR-27a, miR-150, miR-126, miR-210, and miR-155) were analyzed in mouse...... acute malaria. To investigate the involvement of let-7i, miR-27a, and miR-150 in CM-resistant mice, we assessed the expression levels in gamma interferon knockout (IFN-¿(-/-)) mice on a C57BL/6 genetic background. The expression of let-7i, miR-27a, and miR-150 was unchanged in both wild-type (WT...... a regulatory role in the pathogenesis of severe malaria....

  7. Low plasma concentrations of interleukin 10 in severe malarial anaemia compared with cerebral and uncomplicated malaria

    DEFF Research Database (Denmark)

    Kurtzhals, J A; Adabayeri, V; Goka, B Q;


    BACKGROUND: Severe anaemia is a major complication of malaria but little is known about its pathogenesis. Experimental models have implicated tumour necrosis factor (TNF) in induction of bone-marrow suppression and eythrophagocytosis. Conversely, interleukin 10 (IL-10), which mediates feed......-back regulation of TNF, stimulates bone-marrow function in vitro and counteracts anaemia in mice. We investigated the associations of these cytokines with malarial anaemia. METHODS: We enrolled 175 African children with malaria into two studies in 1995 and 1996. In the first study, children were classified...... as having severe anaemia (n=10), uncomplicated malaria (n=26), or cerebral anaemia (n=41). In the second study, patients were classified as having cerebral malaria (n=33) or being fully conscious (n=65), and the two groups were subdivided by measured haemoglobin as normal (>110 g/L), moderate anaemia (60...

  8. Effects of sericin on heme oxygenase-1 expression in the hippocampus and cerebral cortex of type 2 diabetes mellitus rats

    Institute of Scientific and Technical Information of China (English)

    Zhihona Chen; Yaqiang He; Wenliang Fu; Jingfeng Xue


    Previous studies have demonstrated that sericin effectively reduces blood glucose, and protects islet cells, as well as the gonads and kidneys. However, whether sericin improves diabetes mellitus-induced structural and functional problems in the central nervous system remains poorly understood. Rat models of type 2 diabetes mellitus were established by intraperitoneal injection of streptozotocin. The present study observed histological changes in the hippocampus and cerebral cortex, as well as heme oxygenase-1 expression, and explored sericin effects on the central nervous system in diabetic rats. Pathological damage to neural cells in the rat hippocampus and cerebral cortex was relieved following intragastric administration of sericin at a dose of 2.4 g/kg for 35 consecutive days. Heme oxygenase-1 protein and mRNA expressions were decreased in the hippocampus and cerebral cortex of diabetes mellitus rats after sericin treatment. The results suggest that sericin plays a protective effect on the nervous system by decreasing the high expression of heme oxygenase-1 following diabetes mellitus.

  9. Glucagon-like peptide-1 analogue, liraglutide, in experimental cerebral malaria

    DEFF Research Database (Denmark)

    Della Valle, Brian William; Hempel, Casper; Staalsoe, Trine


    BACKGROUND: Cerebral malaria from Plasmodium falciparum infection is major cause of death in the tropics. The pathogenesis of the disease is complex and the contribution of reactive oxygen and nitrogen species (ROS/RNS) in the brain is incompletely understood. Insulinotropic glucagon-like peptide-1...... (GLP-1) mimetics have potent neuroprotective effects in animal models of neuropathology associated with ROS/RNS dysfunction. This study investigates the effect of the GLP-1 analogue, liraglutide against the clinical outcome of experimental cerebral malaria (ECM) and Plasmodium falciparum growth....... Furthermore the role of oxidative stress on ECM pathogenesis is evaluated. METHODS: ECM was induced in Plasmodium berghei ANKA-infected C57Bl/6j mice. Infected Balb/c (non-cerebral malaria) and uninfected C57Bl/6j mice were included as controls. Mice were treated twice-daily with vehicle or liraglutide (200...

  10. Significant association between TIM1 promoter polymorphisms and protection against cerebral malaria in Thailand. (United States)

    Nuchnoi, P; Ohashi, J; Kimura, R; Hananantachai, H; Naka, I; Krudsood, S; Looareesuwan, S; Tokunaga, K; Patarapotikul, J


    Although cerebral malaria is a major life-threatening complication of Plasmodium falciparum infection, its pathophysiology is not well understood. Prolonged activation of the T helper type 1 (Th1) response characterized by the production of pro-inflammatory cytokines such as IFN-gamma and TNF-alpha has been suggested to be responsible for immunopathological process leading to cerebral malaria unless they are downregulated by the anti-inflamatory cytokines produced by the Th2 response. The T cell immunoglobulin and mucin domain (TIM) family of proteins are cell surface proteins involved in regulating Th1 and Th2 immune responses. In this study, the possible association between the polymorphisms of TIM1, TIM3, and TIMD4 genes and the severity of malaria was examined in 478 adult Thai patients infected with P. falciparum malaria. The TIM1 promoter haplotype comprising three derived alleles, -1637A (rs7702919), -1549C (rs41297577) and -1454A (rs41297579), which were in complete linkage disequilibrium, was significantly associated with protection against cerebral malaria (OR = 0.41; 95% CI = 0.24-0.71; P= 0.0009). Allele-specific transcription quantification analysis revealed that the level of mRNA transcribed from TIM1 was higher for the protective promoter haplotype than for the other promoter haplotype (P= 0.004). Engagement with TIM1 in combination with T cell receptor stimulation induces anti-inflammatory Th2 cytokine production, which can protect the development of cerebral malaria caused by overproduction of pro-inflammatory Th1 cytokines. The present results suggest that the higher TIM1 expression associated with the protective TIM1 promoter haplotype confers protection against cerebral malaria.

  11. Gene expression analysis reveals early changes in several molecular pathways in cerebral malaria-susceptible mice versus cerebral malaria-resistant mice

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    Grau Georges E


    Full Text Available Abstract Background Microarray analyses allow the identification and assessment of molecular signatures in whole tissues undergoing pathological processes. To better understand cerebral malaria pathogenesis, we investigated intra-cerebral gene-expression profiles in well-defined genetically cerebral malaria-resistant (CM-R and CM-susceptible (CM-S mice, upon infection by Plasmodium berghei ANKA (PbA. We investigated mouse transcriptional responses at early and late stages of infection by use of cDNA microarrays. Results Through a rigorous statistical approach with multiple testing corrections, we showed that PbA significantly altered brain gene expression in CM-R (BALB/c, and in CM-S (CBA/J and C57BL/6 mice, and that 327 genes discriminated between early and late infection stages, between mouse strains, and between CM-R and CM-S mice. We further identified 104, 56, 84 genes with significant differential expression between CM-R and CM-S mice on days 2, 5, and 7 respectively. The analysis of their functional annotation indicates that genes involved in metabolic energy pathways, the inflammatory response, and the neuroprotection/neurotoxicity balance play a major role in cerebral malaria pathogenesis. In addition, our data suggest that cerebral malaria and Alzheimer's disease may share some common mechanisms of pathogenesis, as illustrated by the accumulation of β-amyloid proteins in brains of CM-S mice, but not of CM-R mice. Conclusion Our microarray analysis highlighted marked changes in several molecular pathways in CM-S compared to CM-R mice, particularly at early stages of infection. This study revealed some promising areas for exploration that may both provide new insight into the knowledge of CM pathogenesis and the development of novel therapeutic strategies.

  12. Polymorphisms in the RNASE3 gene are associated with susceptibility to cerebral malaria in Ghanaian children

    DEFF Research Database (Denmark)

    Adu, Bright; Dodoo, Daniel; Adukpo, Selorme


    Cerebral malaria (CM) is the most severe outcome of Plasmodium falciparum infection and a major cause of death in children from 2 to 4 years of age. A hospital based study in Ghana showed that P. falciparum induces eosinophilia and found a significantly higher serum level of eosinophil cationic...... protein (ECP) in CM patients than in uncomplicated malaria (UM) and severe malaria anemia (SA) patients. Single nucleotide polymorphisms (SNPs) have been described in the ECP encoding-gene (RNASE3) of which the c.371G>C polymorphism (rs2073342) results in an arginine to threonine amino acid substitution p...

  13. Cytokine response during non-cerebral and cerebral malaria: evidence of a failure to control inflammation as a cause of death in African adults

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    Yakhya Dieye


    Full Text Available Background. With 214 million cases and 438,000 deaths in 2015, malaria remains one of the deadliest infectious diseases in tropical countries. Several species of the protozoan Plasmodium cause malaria. However, almost all the fatalities are due to Plasmodium falciparum, a species responsible for the severest cases including cerebral malaria. Immune response to Plasmodium falciparum infection is mediated by the production of pro-inflammatory cytokines, chemokines and growth factors whose actions are crucial for the control of the parasites. Following this response, the induction of anti-inflammatory immune mediators downregulates the inflammation thus preventing its adverse effects such as damages to various organs and death. Methods. We performed a retrospective, nonprobability sampling study using clinical data and sera samples from patients, mainly adults, suffering of non-cerebral or cerebral malaria in Dakar, Sénégal. Healthy individuals residing in the same area were included as controls. We measured the serum levels of 29 biomarkers including growth factors, chemokines, inflammatory and anti-inflammatory cytokines. Results. We found an induction of both pro- and anti-inflammatory immune mediators during malaria. The levels of pro-inflammatory biomarkers were higher in the cerebral malaria than in the non-cerebral malaria patients. In contrast, the concentrations of anti-inflammatory cytokines were comparable in these two groups or lower in CM patients. Additionally, four pro-inflammatory biomarkers were significantly increased in the deceased of cerebral malaria compared to the survivors. Regarding organ damage, kidney failure was significantly associated with death in adults suffering of cerebral malaria. Conclusions. Our results suggest that a poorly controlled inflammatory response determines a bad outcome in African adults suffering of cerebral malaria.

  14. Mannitol and other osmotic diuretics as adjuncts for treating cerebral malaria (United States)

    Okoromah, Christy AN; Afolabi, Bosede B; Wall, Emma CB


    Background Cerebral oedema occurs with cerebral malaria, and some clinicians think osmotic diuretics, such as mannitol or urea, may improve outcomes. Objectives To compare mannitol or urea to placebo or no diuretic for treating children or adults with cerebral malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register (Issue 4, 2010), CENTRAL (The Cochrane Library Issue 12, 2010), MEDLINE (1966 to November 2010), EMBASE (1974 to November 2010), LILACS (1982 to November 2010), and the reference lists of articles. We contacted relevant organizations and researchers. Selection criteria Randomized or quasi-randomized controlled trials comparing mannitol or urea to placebo or no treatment in children and adults with cerebral malaria. Primary outcomes were death, life-threatenining sequelae and major neurological sequelae at six months. Data collection and analysis Two authors applied the inclusion criteria, assessed risk of bias, and extracted data independently. Main results One trial met the inclusion criteria, comparing mannitol 20% to saline placebo in 156 Ugandan children. Allocation was concealed. No difference in mortality, time to regain consciousness, or neurological sequelae were detected. Authors’ conclusions There are insufficient data to know what the effects of osmotic diuretics are in children with cerebral malaria. Larger, multicentre trials are needed. PMID:21491391

  15. Coma in fatal adult human malaria is not caused by cerebral oedema

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    Pongponratn Emsri


    Full Text Available Abstract Background The role of brain oedema in the pathophysiology of cerebral malaria is controversial. Coma associated with severe Plasmodium falciparum malaria is multifactorial, but associated with histological evidence of parasitized erythrocyte sequestration and resultant microvascular congestion in cerebral vessels. To determine whether these changes cause breakdown of the blood-brain barrier and resultant perivascular or parenchymal cerebral oedema, histology, immunohistochemistry and image analysis were used to define the prevalence of histological patterns of oedema and the expression of specific molecular pathways involved in water balance in the brain in adults with fatal falciparum malaria. Methods The brains of 20 adult Vietnamese patients who died of severe malaria were examined for evidence of disrupted vascular integrity. Immunohistochemistry and image analysis was performed on brainstem sections for activation of the vascular endothelial growth factor (VEGF receptor 2 and expression of the aquaporin 4 (AQP4 water channel protein. Fibrinogen immunostaining was assessed as evidence of blood-brain barrier leakage and perivascular oedema formation. Correlations were performed with clinical, biochemical and neuropathological parameters of severe malaria infection. Results The presence of oedema, plasma protein leakage and evidence of VEGF signalling were heterogeneous in fatal falciparum malaria and did not correlate with pre-mortem coma. Differences in vascular integrity were observed between brain regions with the greatest prevalence of disruption in the brainstem, compared to the cortex or midbrain. There was a statistically non-significant trend towards higher AQP4 staining in the brainstem of cases that presented with coma (P = .02. Conclusions Histological evidence of cerebral oedema or immunohistochemical evidence of localised loss of vascular integrity did not correlate with the occurrence of pre-mortem coma in adults with

  16. Differences in gene transcriptomic pattern of Plasmodium falciparum in children with cerebral malaria and asymptomatic carriers

    DEFF Research Database (Denmark)

    Almelli, Talleh; Nuel, Grégory; Bischoff, Emmanuel;


    , transcriptional factor proteins, proteins implicated in protein transport, as well as Plasmodium conserved and hypothetical proteins. Interestingly, UPs A1, A2, A3 and UPs B1 of var genes were predominantly found in cerebral malaria-associated isolates and those containing architectural domains of DC4, DC5, DC13...

  17. Multivariate modelling with 1H NMR of pleural effusion in murine cerebral malaria

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    Ghosh Soumita


    Full Text Available Abstract Background Cerebral malaria is a clinical manifestation of Plasmodium falciparum infection. Although brain damage is the predominant pathophysiological complication of cerebral malaria (CM, respiratory distress, acute lung injury, hydrothorax/pleural effusion are also observed in several cases. Immunological parameters have been assessed in pleural fluid in murine models; however there are no reports of characterization of metabolites present in pleural effusion. Methods 1H NMR of the sera and the pleural effusion of cerebral malaria infected mice were analyzed using principal component analysis, orthogonal partial least square analysis, multiway principal component analysis, and multivariate curve resolution. Results It has been observed that there was 100% occurrence of pleural effusion (PE in the mice affected with CM, as opposed to those are non-cerebral and succumbing to hyperparasitaemia (NCM/HP. An analysis of 1H NMR and SDS-PAGE profile of PE and serum samples of each of the CM mice exhibited a similar profile in terms of constituents. Multivariate analysis on these two classes of biofluids was performed and significant differences were detected in concentrations of metabolites. Glucose, creatine and glutamine contents were high in the PE and lipids being high in the sera. Multivariate curve resolution between sera and pleural effusion showed that changes in PE co-varied with that of serum in CM mice. The increase of glucose in PE is negatively correlated to the glucose in serum in CM as obtained from the result of multiway principal component analysis. Conclusions This study reports for the first time, the characterization of metabolites in pleural effusion formed during murine cerebral malaria. The study indicates that the origin of PE metabolites in murine CM may be the serum. The loss of the components like glucose, glutamine and creatine into the PE may worsen the situation of patients, in conjunction with the enhanced

  18. Association of Heme Oxygenase 1 with Lung Protection in Malaria-Associated ALI/ARDS (United States)

    Pereira, Marcelo L. M.; Ortolan, Luana S.; Sercundes, Michelle K.; Debone, Daniela; Murillo, Oscar; Lima, Flávia A.


    Malaria is a serious disease, caused by the parasite of the genus Plasmodium, which was responsible for 440,000 deaths in 2015. Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is one of the main clinical complications in severe malaria. The murine model DBA/2 reproduces the clinical signs of ALI/ARDS in humans, when infected with Plasmodium berghei ANKA. High levels of HO-1 were reported in cases of severe malaria. Our data indicated that the HO-1 mRNA and protein expression are increased in mice that develop malaria-associated ALI/ARDS (MA-ALI/ARDS). Additionally, the hemin, a HO-1 inducing drug, prevented mice from developing MA-ALI/ARDS when administered prior to the development of MA-ALI/ARDS in this model. Also, hemin treatment showed an amelioration of respiratory parameters in mice, high VEGF levels in the sera, and a decrease in vascular permeability in the lung, which are signs of ALI/ARDS. Therefore, the induction of HO-1 before the development of MA-ALI/ARDS could be protective. However, the increased expression of HO-1 on the onset of MA-ALI/ARDS development may represent an effort to revert the phenotype of this syndrome by the host. We therefore confirm that HO-1 inducing drugs could be used for prevention of MA-ALI/ARDS in humans. PMID:27974865

  19. Elevated cell-specific microparticles are a biological marker for cerebral dysfunctions in human severe malaria.

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    Joël Bertrand Pankoui Mfonkeu

    Full Text Available Cerebral malaria (CM and severe anemia (SA are the most severe complications of Plasmodium falciparum infections. Although increased release of endothelial microparticles (MP correlates with malaria severity, the full extent of vascular cell vesiculation remains unknown. Here, we characterize the pattern of cell-specific MP in patients with severe malaria. We tested the hypothesis that systemic vascular activation contributes to CM by examining origins and levels of plasma MP in relation to clinical syndromes, disease severity and outcome. Patients recruited in Douala, Cameroon, were assigned to clinical groups following WHO criteria. MP quantitation and phenotyping were carried out using cell-specific markers by flow cytometry using antibodies recognizing cell-specific surface markers. Platelet, erythrocytic, endothelial and leukocytic MP levels were elevated in patients with cerebral dysfunctions and returned to normal by discharge. In CM patients, platelet MP were the most abundant and their levels significantly correlated with coma depth and thrombocytopenia. This study shows for the first time a widespread enhancement of vesiculation in the vascular compartment appears to be a feature of CM but not of SA. Our data underpin the role of MP as a biomarker of neurological involvement in severe malaria. Therefore, intervention to block MP production in severe malaria may provide a new therapeutic pathway.

  20. [Cerebral malaria with renal insufficiency in a 5 months pregnant woman. The use of prostaglandines for delivery (author's transl)]. (United States)

    Thonnier, C; Bruneu, A; Valmary, J; Capdevielle, P; Delprat, J


    Report of a typical case of cerebral malaria with coma during 3 days, pneumopathy and renal insufficiency with failure of concentration. The delivery of a dead foetus has been started by prostaglandines.

  1. Tin chloride enhances parvalbumin-positive interneuron survival by modulating heme metabolism in a model of cerebral ischemia. (United States)

    Li Volti, Giovanni; Zappalà, Agata; Leggio, Gian Marco; Mazzola, Carmen; Drago, Filippo; La Delia, Francesco; Serapide, Maria Francesca; Pellitteri, Rosalia; Giannone, Ignazio; Spatuzza, Michela; Cicirata, Valentina; Cicirata, Federico


    SnCl(2) has been reported to increase the expression of heme-oxygenase 1 (HO-1), a major antioxidant enzyme, and to decrease ischemic injury, in non-nervous tissues. This study examined the neuroprotective effect of SnCl(2) in the hippocampus of rats submitted to cerebral ischemia. SnCl(2) was administered 18 h before bilateral carotids obstruction. Changes in HO-1 expression and activity, heme content, inducible nitric oxide synthase (iNOS) expression and parvalbumin positive interneuron survival were studied. Thereafter both behavior and memory recovery were tested. The administration of SnCl(2) increased the expression of HO-1 protein and HO activity in the hippocampus and concomitantly decreased heme content at both mitochondrial and nuclear level. Furthermore, ischemized animals showed a strong increase in iNOS expression in the hippocampus, where a loss of parvalbumin positive interneurons also occurred. Pre-treatment with SnCl(2), decreased both iNOS expression in ischemized rats and increased cell survival. The beneficial effects of SnCl(2) were prevented by concomitant treatment with SnMP, a strong inhibitor of HO activity. SnCl(2) also caused an improvement in short term memory recovery. Our results showed that following SnCl(2) administration, HO-1 is strongly induced in the hippocampus and modulate iNOS expression, resulting in a strong neuroprotective effect.

  2. Cerebral Malaria: An Unusual Cause of Central Diabetes Insipidus. (United States)

    Premji, Resmi; Roopnarinesingh, Nira; Cohen, Joshua; Sen, Sabyasachi


    Central diabetes insipidus is an uncommon feature of malaria. A previously healthy 72-year-old man presented with fever, rigors, and altered mental status after a recent trip to Liberia, a country known for endemic falciparum malaria. Investigations confirmed plasmodium falciparum parasitemia. Within one week after admission, the serum sodium rose to 166 mEq/L and the urine output increased to 7 liters/day. Other labs were notable for a high serum osmolality, low urine osmolality, and low urine specific gravity. The hypernatremia did not respond to hypotonic fluids. Diabetes insipidus was suspected and parenteral desmopressin was started with a prompt decrease in urinary output and improvement in mental status. Additional testing showed normal anterior pituitary hormones. The desmopressin was eventually tapered off with complete resolution of symptoms. Central diabetes insipidus occurred likely as a result of obstruction of the neurohypophyseal microvasculature. Other endocrinopathies that have been reported with malaria include hyponatremia, adrenal insufficiency, hypothyroidism, hypocalcemia, hypophosphatemia, hyper-, and hypoglycemia, but none manifested in our patient. Though diabetes insipidus is a rare complication of malaria, clinicians need to be aware of this manifestation, as failure to do so may lead to fatality particularly if the patient is dehydrated.

  3. Cerebral Malaria: An Unusual Cause of Central Diabetes Insipidus

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    Resmi Premji


    Full Text Available Central diabetes insipidus is an uncommon feature of malaria. A previously healthy 72-year-old man presented with fever, rigors, and altered mental status after a recent trip to Liberia, a country known for endemic falciparum malaria. Investigations confirmed plasmodium falciparum parasitemia. Within one week after admission, the serum sodium rose to 166 mEq/L and the urine output increased to 7 liters/day. Other labs were notable for a high serum osmolality, low urine osmolality, and low urine specific gravity. The hypernatremia did not respond to hypotonic fluids. Diabetes insipidus was suspected and parenteral desmopressin was started with a prompt decrease in urinary output and improvement in mental status. Additional testing showed normal anterior pituitary hormones. The desmopressin was eventually tapered off with complete resolution of symptoms. Central diabetes insipidus occurred likely as a result of obstruction of the neurohypophyseal microvasculature. Other endocrinopathies that have been reported with malaria include hyponatremia, adrenal insufficiency, hypothyroidism, hypocalcemia, hypophosphatemia, hyper-, and hypoglycemia, but none manifested in our patient. Though diabetes insipidus is a rare complication of malaria, clinicians need to be aware of this manifestation, as failure to do so may lead to fatality particularly if the patient is dehydrated.

  4. Neurocognitive sequelae of cerebral malaria in adults:A pilot study in Benguela Central Hospital, Angola

    Institute of Scientific and Technical Information of China (English)

    Bruno Peixoto; Isabel Kalei


    Objective: To characterize the neurocognitive sequelae of cerebral malaria (CM) in an adult sample of the city of Benguela, Angola. Methods:A neuropsychological assessment was carried out in 22 subjects with prior history of CM ranging from 6 to 12 months after the infection. The obtained results were compared to a control group with no previous history of cerebral malaria. The study was conducted in Benguela Central Hospital, Angola in 2011. Results: CM group obtained lower results on the two last trials of a verbal learning task and on an abstract reasoning test. Conclusions: CM is associated to a slower verbal learning rate and to difficulties in the ability to discriminate and perceive relations between new elements.

  5. Potential efficacy of citicoline as adjunct therapy in treatment of cerebral malaria. (United States)

    El-Assaad, Fatima; Combes, Valery; Grau, Georges Emile Raymond; Jambou, Ronan


    Cerebral malaria (CM) is characterized by a dysregulated immune response that results in endothelial membrane destabilization and increased microparticle (MP) production. Citicoline (CTC) is a membrane stabilizer used for the treatment of neurological disorders. We evaluated the efficacy of CTC as adjunct therapy to aid recovery from experimental CM. We show that CTC reduces MP production in vitro; in combination with artesunate in vivo, confers partial protection against CM; and prolongs survival.

  6. Transcriptomic profiling of microglia reveals signatures of cell activation and immune response, during experimental cerebral malaria (United States)

    Capuccini, Barbara; Lin, Jingwen; Talavera-López, Carlos; Khan, Shahid M.; Sodenkamp, Jan; Spaccapelo, Roberta; Langhorne, Jean


    Cerebral malaria is a pathology involving inflammation in the brain. There are many immune cell types activated during this process, but there is little information on the response of microglia, in this severe complication. We examined microglia by genome wide transcriptomic analysis in a model of experimental cerebral malaria (ECM), in which C57BL/6 mice are infected with Plasmodium berghei ANKA. Thousands of transcripts were differentially expressed in microglia at two different time points during infection. Proliferation of microglia was a dominant feature before the onset of ECM, and supporting this, we observed an increase in numbers of these cells in the brain. When cerebral malaria symptoms were manifest, genes involved in immune responses and chemokine production were upregulated, which were possibly driven by Type I Interferon. Consistent with this hypothesis, in vitro culture of a microglial cell line with Interferon-β, but not infected red blood cells, resulted in production of several of the chemokines shown to be upregulated in the gene expression analysis. It appears that these responses are associated with ECM, as microglia from mice infected with a mutant P. berghei parasite (ΔDPAP3), which does not cause ECM, did not show the same level of activation or proliferation. PMID:27991544

  7. Heme-mediated apoptosis and fusion damage in BeWo trophoblast cells (United States)

    Liu, Mingli; Hassana, Salifu; Stiles, Jonathan K.


    Placental malaria (PM) is a complication associated with malaria infection during pregnancy that often leads to abortion, premature delivery, intrauterine growth restriction and low birth weight. Increased levels of circulating free heme, a by-product of Plasmodium-damaged erythrocytes, is a major contributor to inflammation, tissue damage and loss of blood brain barrier integrity associated with fatal experimental cerebral malaria. However, the role of heme in PM remains unknown. Proliferation and apoptosis of trophoblasts and fusion of the mononucleated state to the syncytial state are of major importance to a successful pregnancy. In the present study, we examined the effects of heme on the viability and fusion of a trophoblast-derived cell line (BeWo). Results indicate that heme induces apoptosis in BeWo cells by activation of the STAT3/caspase-3/PARP signaling pathway. In the presence of forskolin, which triggers trophoblast fusion, heme inhibits BeWo cell fusion through activation of STAT3. Understanding the effects of free plasma heme in pregnant women either due to malaria, sickle cell disease or other hemolytic diseases, will enable identification of high-risk women and may lead to discovery of new drug targets against associated adverse pregnancy outcome. PMID:27796349

  8. Value of Plasmodium falciparum Histidine-Rich Protein 2 Level and Malaria Retinopathy in Distinguishing Cerebral Malaria From Other Acute Encephalopathies in Kenyan Children (United States)

    Kariuki, Symon M.; Gitau, Evelyn; Gwer, Samson; Karanja, Henry K.; Chengo, Eddie; Kazungu, Michael; Urban, Britta C.; Newton, Charles R. J. C.


    Background. The diagnosis of cerebral malaria is problematic in malaria-endemic areas because encephalopathy in patients with parasitemia may have another cause. Abnormal retinal findings are thought to increase the specificity of the diagnosis, and the level of histidine-rich protein 2 (HRP2) may reflect the parasite biomass. Methods. We examined the retina and measured plasma HRP2 levels in children with acute nontraumatic encephalopathy in Kenya. Logistic regression, with HRP2 level as an independent variable and World Health Organization–defined cerebral malaria and/or retinopathy as the outcome, was used to calculate malaria-attributable fractions (MAFs) and retinopathy-attributable fractions (RAFs). Results. Of 270 children, 140 (52%) had peripheral parasitemia, 80 (30%) had malaria retinopathy, and 164 (61%) had an HRP2 level of >0 U/mL. During 2006–2011, the incidence of HRP2 positivity among admitted children declined by 49 cases per 100 000 per year (a 78% reduction). An HRP2 level of >0 U/mL had a MAF of 93% for cerebral malaria, with a MAF of 97% observed for HRP2 levels of ≥10 U/mL (the level of the best combined sensitivity and specificity). HRP2 levels of >0 U/mL had a RAF of 77% for features of retinopathy combined, with the highest RAFs for macular whitening (99%), peripheral whitening (98%), and hemorrhages (90%). Conclusion. HRP2 has a high attributable fraction for features of malarial retinopathy, supporting its use in the diagnosis of cerebral malaria. HRP2 thresholds improve the specificity of the definition. PMID:24041795

  9. CNS hypoxia is more pronounced in murine cerebral than noncerebral malaria and is reversed by erythropoietin

    DEFF Research Database (Denmark)

    Hempel, Casper; Combes, Valery; Hunt, Nicholas Henry;


    -ribose) polymerase-1 (PARP-1) gene knockout mice. The effect of erythropoietin, an oxygen-sensitive cytokine that mediates protection against CM, on cerebral hypoxia was studied in C57BL/6 mice. Numerous hypoxic foci of neurons and glial cells were observed in mice with CM. Substantially fewer and smaller foci were...... observed in mice without CM, and hypoxia seemed to be confined to neuronal cell somas. PARP-1-deficient mice were not protected against CM, which argues against a role for cytopathic hypoxia. Erythropoietin therapy reversed the development of CM and substantially reduced the degree of neural hypoxia......Cerebral malaria (CM) is associated with high mortality and risk of sequelae, and development of adjunct therapies is hampered by limited knowledge of its pathogenesis. To assess the role of cerebral hypoxia, we used two experimental models of CM, Plasmodium berghei ANKA in CBA and C57BL/6 mice...

  10. Pathogenic roles of CD14, galectin-3, and OX40 during experimental cerebral malaria in mice.

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    Miranda S Oakley

    Full Text Available An in-depth knowledge of the host molecules and biological pathways that contribute towards the pathogenesis of cerebral malaria would help guide the development of novel prognostics and therapeutics. Genome-wide transcriptional profiling of the brain tissue during experimental cerebral malaria (ECM caused by Plasmodium berghei ANKA parasites in mice, a well established surrogate of human cerebral malaria, has been useful in predicting the functional classes of genes involved and pathways altered during the course of disease. To further understand the contribution of individual genes to the pathogenesis of ECM, we examined the biological relevance of three molecules -- CD14, galectin-3, and OX40 that were previously shown to be overexpressed during ECM. We find that CD14 plays a predominant role in the induction of ECM and regulation of parasite density; deletion of the CD14 gene not only prevented the onset of disease in a majority of susceptible mice (only 21% of CD14-deficient compared to 80% of wildtype mice developed ECM, p<0.0004 but also had an ameliorating effect on parasitemia (a 2 fold reduction during the cerebral phase. Furthermore, deletion of the galectin-3 gene in susceptible C57BL/6 mice resulted in partial protection from ECM (47% of galectin-3-deficient versus 93% of wildtype mice developed ECM, p<0.0073. Subsequent adherence assays suggest that galectin-3 induced pathogenesis of ECM is not mediated by the recognition and binding of galectin-3 to P. berghei ANKA parasites. A previous study of ECM has demonstrated that brain infiltrating T cells are strongly activated and are CD44(+CD62L(- differentiated memory T cells [1]. We find that OX40, a marker of both T cell activation and memory, is selectively upregulated in the brain during ECM and its distribution among CD4(+ and CD8(+ T cells accumulated in the brain vasculature is approximately equal.

  11. Heme-Mediated Induction of CXCL10 and Depletion of CD34+ Progenitor Cells Is Toll-Like Receptor 4 Dependent.

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    Carmen M Dickinson-Copeland

    Full Text Available Plasmodium falciparum infection can cause microvascular dysfunction, cerebral encephalopathy and death if untreated. We have previously shown that high concentrations of free heme, and C-X-C motif chemokine 10 (CXCL10 in sera of malaria patients induce apoptosis in microvascular endothelial and neuronal cells contributing to vascular dysfunction, blood-brain barrier (BBB damage and mortality. Endothelial progenitor cells (EPC are microvascular endothelial cell precursors partly responsible for repair and regeneration of damaged BBB endothelium. Studies have shown that EPC's are depleted in severe malaria patients, but the mechanisms mediating this phenomenon are unknown. Toll-like receptors recognize a wide variety of pathogen-associated molecular patterns generated by pathogens such as bacteria and parasites. We tested the hypothesis that EPC depletion during malaria pathogenesis is a function of heme-induced apoptosis mediated by CXCL10 induction and toll-like receptor (TLR activation. Heme and CXCL10 concentrations in plasma obtained from malaria patients were elevated compared with non-malaria subjects. EPC numbers were significantly decreased in malaria patients (P < 0.02 and TLR4 expression was significantly elevated in vivo. These findings were confirmed in EPC precursors in vitro; where it was determined that heme-induced apoptosis and CXCL10 expression was TLR4-mediated. We conclude that increased serum heme mediates depletion of EPC during malaria pathogenesis.

  12. Malaria (United States)

    ... and can even be fatal. SymptomsWhat are the symptoms of malaria?The symptoms of malaria include:High fever (can often be 104° F ... give someone else malaria?If I do get malaria, should I travel while I have symptoms? Other organizationsInternational Society of Travel MedicineCenters for Disease ...

  13. Increased susceptibility to pentylenetetrazol following survival of cerebral malaria in mice. (United States)

    Grauncke, Ana C B; Souza, Thaíze L; Ribeiro, Leandro R; Brant, Fátima; Machado, Fabiana S; Oliveira, Mauro S


    Malaria is considered a neglected disease and public health problem, affecting >200 million people worldwide. In the present study we used the Plasmodium berghei ANKA (PbA) model of experimental cerebral malaria (CM) in C57BL/6 mice. After rescue from CM and parasite clearance, animals were submitted to a seizure susceptibility test (45 days after infection) using a low dose of pentylenetetrazol (PTZ, 30 mg/kg) and monitored with use of behavioral and electroencephalography (EEG) methods. Mice rescued from CM presented a reduced latency to myoclonic and tonic-clonic seizures and an increased duration of tonic-clonic seizures. In addition, quantitative analysis of EEG revealed a decrease in relative power at beta frequency band in PbA-infected animals after PTZ injection. Our results suggest that CM may lead to increased susceptibility to seizures in mice.

  14. Histamine H(3 receptor-mediated signaling protects mice from cerebral malaria.

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    Walid Beghdadi

    Full Text Available BACKGROUND: Histamine is a biogenic amine that has been shown to contribute to several pathological conditions, such as allergic conditions, experimental encephalomyelitis, and malaria. In humans, as well as in murine models of malaria, increased plasma levels of histamine are associated with severity of infection. We reported recently that histamine plays a critical role in the pathogenesis of experimental cerebral malaria (CM in mice infected with Plasmodium berghei ANKA. Histamine exerts its biological effects through four different receptors designated H1R, H2R, H3R, and H4R. PRINCIPAL FINDINGS: In the present work, we explored the role of histamine signaling via the histamine H3 receptor (H3R in the pathogenesis of murine CM. We observed that the lack of H3R expression (H3R(-/- mice accelerates the onset of CM and this was correlated with enhanced brain pathology and earlier and more pronounced loss of blood brain barrier integrity than in wild type mice. Additionally tele-methylhistamine, the major histamine metabolite in the brain, that was initially present at a higher level in the brain of H3R(-/- mice was depleted more quickly post-infection in H3R(-/- mice as compared to wild-type counterparts. CONCLUSIONS: Our data suggest that histamine regulation through the H3R in the brain suppresses the development of CM. Thus modulating histamine signaling in the central nervous system, in combination with standard therapies, may represent a novel strategy to reduce the risk of progression to cerebral malaria.

  15. Plasma IP-10, apoptotic and angiogenic factors associated with fatal cerebral malaria in India

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    Dash AP


    Full Text Available Abstract Background Plasmodium falciparum in a subset of patients can lead to cerebral malaria (CM, a major contributor to malaria-associated mortality. Despite treatment, CM mortality can be as high as 30%, while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM is mediated by alterations in cytokine and chemokine homeostasis, inflammation as well as vascular injury and repair processes although their roles are not fully understood. The hypothesis for this study is that CM-induced changes in inflammatory, apoptotic and angiogenic factors mediate severity of CM and that their identification will enable development of new prognostic markers and adjunctive therapies for preventing CM mortalities. Methods Plasma samples (133 were obtained from healthy controls (HC, 25, mild malaria (MM, 48, cerebral malaria survivors (CMS, 48, and cerebral malaria non-survivors (CMNS, 12 at admission to the hospital in Jabalpur, India. Plasma levels of 30 biomarkers ((IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-12 (p70, IL-13, IL-15, IL-17, Eotaxin, FGF basic protein, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1 (MCAF, MIP-1α, MIP-1β, RANTES, TNF-α, Fas-ligand (Fas-L, soluble Fas (sFas, soluble TNF receptor 1 (sTNF-R1 and soluble TNF receptor 2 (sTNFR-2, PDGF bb and VEGF were simultaneously measured in an initial subset of ten samples from each group. Only those biomarkers which showed significant differences in the pilot analysis were chosen for testing on all remaining samples. The results were then compared between the four groups to determine their role in CM severity. Results IP-10, sTNF-R2 and sFas were independently associated with increased risk of CM associated mortality. CMNS patients had a significantly lower level of the neuroprotective factor VEGF when compared to other groups (P Conclusion The results suggest that plasma levels of IP-10, sTNF-R2 and sFas may be potential

  16. Protection from experimental cerebral malaria with a single dose of radiation-attenuated, blood-stage Plasmodium berghei parasites.

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    Noel J Gerald

    Full Text Available BACKGROUND: Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. METHODOLOGY AND RESULTS: We used radiation exposure to attenuate the highly virulent asexual blood stages of the murine malaria parasite P. berghei to a non-replicable, avirulent form. We tested the ability of the attenuated blood stage parasites to induce immunity to parasitemia and the symptoms of severe malaria disease. Depending on the mouse genetic background, a single high dose immunization without adjuvant protected mice from parasitemia and severe disease (CD1 mice or from experimental cerebral malaria (ECM (C57BL/6 mice. A low dose immunization did not protect against parasitemia or severe disease in either model after one or two immunizations. The protection from ECM was associated with a parasite specific antibody response and also with a lower level of splenic parasite-specific IFN-γ production, which is a mediator of ECM pathology in C57BL/6 mice. Surprisingly, there was no difference in the sequestration of CD8+ T cells and CD45+ CD11b+ macrophages in the brains of immunized, ECM-protected mice. CONCLUSIONS: This report further demonstrates the effectiveness of a whole parasite blood-stage vaccine in inducing immunity to malaria and explicitly demonstrates its effectiveness against ECM, the most pathogenic consequence of malaria infection. This experimental model will be important to explore the formulation of whole parasite blood-stage vaccines against malaria and to investigate the immune mechanisms that mediate protection against parasitemia and cerebral malaria.

  17. Retinopathy in severe malaria in Ghanaian children - overlap between fundus changes in cerebral and non-cerebral malaria

    DEFF Research Database (Denmark)

    Essuman, Vera A; Ntim-Amponsah, Christine T; Astrup, Birgitte S


    . Secondly, to determine any association between retinopathy and the occurrence of convulsions in patients with CM. Methods and subjects A cross-sectional study of consecutive patients on admission with severe malaria who were assessed for retinal signs, at the Department of Child Health, Korle-Bu Teaching...... Hospital, Accra, from July to August 2002 was done. All children had dilated-fundus examination by direct and indirect ophthalmoscopy. RESULTS: Fifty-eight children aged between six months and nine years were recruited. Twenty six(45%) had CM, 22 with convulsion; 26(45%) had SA and six(10%) had RD. Any...... retinopathy was seen in: CM 19(73%), SA 14(54%), RD 3(50.0%), CM with convulsion 15(68%) and CM without convulsion 4(100%). Comparison between CM versus non-CM groups showed a significant risk relationship between retinal whitening and CM(OR=11.0, CI=2.2- 56.1, p= 0.001). There was no significant association...

  18. Brain-derived neurotrophic factor and the course of experimental cerebral malaria. (United States)

    Linares, María; Marín-García, Patricia; Pérez-Benavente, Susana; Sánchez-Nogueiro, Jesús; Puyet, Antonio; Bautista, José M; Diez, Amalia


    The role of neurotrophic factors on the integrity of the central nervous system (CNS) during cerebral malaria (CM) infection remains obscure, but the long-standing neurocognitive sequelae often observed in rescued children can be attributed in part to the modulation of neuronal survival and synaptic plasticity. To discriminate the contribution of key responses in the time-sequence of the pathogenic events that trigger the development of neurocognitive malaria syndrome we defined four stages (I-IV) of the neurological progression of CM in C57BL/6 mice infected with Plasmodium berghei ANKA. Upregulation of ICAM-1, VCAM-1, e-selectin and p-selectin expression was detected in all cerebral regions before parasitized red blood cells (pRBC) accumulation. As the severity of symptoms increased, BDNF mRNA progressively diminished in several brain regions, earliest in the thalamus-hypothalamus, cerebellum, brainstem and cortex, and correlated with a four-stage disease sequence. Immunohistochemical confocal microscopy revealed changes in the BDNF distribution pattern, suggesting altered axonal transport. During CM progression, molecular markers of neurological infection and inflammation in the parasite and the host, respectively, were accompanied by a switch in the brain constitutive proteasome to the immunoproteasome, which could impede normal protein turnover. In parallel with BDNF downregulation, NCAM expression also diminished with increased CM severity. Together, these data suggest that changes in BDNF availability could be involved in the pathogenesis of CM.

  19. Malaria. (United States)

    Dupasquier, Isabelle


    Malaria, the greatest pandemia in the world, claims an estimated one million lives each year in Africa alone. While it may still be said that for the most part malaria is found in what is known as the world's poverty belt, cases are now frequently diagnosed in western countries. Due to resistant strains of malaria which have developed because of…

  20. Differential PfEMP1 Expression Is Associated with Cerebral Malaria Pathology (United States)

    Tembo, Dumizulu L.; Nyoni, Benjamin; Murikoli, Rekah V.; Mukaka, Mavuto; Milner, Danny A.; Berriman, Matthew; Rogerson, Stephen J.; Taylor, Terrie E.; Molyneux, Malcolm E.; Mandala, Wilson L.; Craig, Alister G.; Montgomery, Jacqui


    Plasmodium falciparum is unique among human malarias in its ability to sequester in post-capillary venules of host organs. The main variant antigens implicated are the P. falciparum erythrocyte membrane protein 1 (PfEMP1), which can be divided into three major groups (A–C). Our study was a unique examination of sequestered populations of parasites for genetic background and expression of PfEMP1 groups. We collected post-mortem tissue from twenty paediatric hosts with pathologically different forms of cerebral malaria (CM1 and CM2) and parasitaemic controls (PC) to directly examine sequestered populations of parasites in the brain, heart and gut. Use of two different techniques to investigate this question produced divergent results. By quantitative PCR, group A var genes were upregulated in all three organs of CM2 and PC cases. In contrast, in CM1 infections displaying high levels of sequestration but negligible vascular pathology, there was high expression of group B var. Cloning and sequencing of var transcript tags from the same samples indicated a uniformly low expression of group A-like var. Generally, within an organ sample, 1–2 sequences were expressed at dominant levels. 23% of var tags were detected in multiple patients despite the P. falciparum infections being genetically distinct, and two tags were observed in up to seven hosts each with high expression in the brains of 3–4 patients. This study is a novel examination of the sequestered parasites responsible for fatal cerebral malaria and describes expression patterns of the major cytoadherence ligand in three organ-derived populations and three pathological states. PMID:25473835

  1. Perivascular Arrest of CD8+ T Cells Is a Signature of Experimental Cerebral Malaria.

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    Tovah N Shaw

    Full Text Available There is significant evidence that brain-infiltrating CD8+ T cells play a central role in the development of experimental cerebral malaria (ECM during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the mechanisms through which they mediate their pathogenic activity during malaria infection remain poorly understood. Utilizing intravital two-photon microscopy combined with detailed ex vivo flow cytometric analysis, we show that brain-infiltrating T cells accumulate within the perivascular spaces of brains of mice infected with both ECM-inducing (P. berghei ANKA and non-inducing (P. berghei NK65 infections. However, perivascular T cells displayed an arrested behavior specifically during P. berghei ANKA infection, despite the brain-accumulating CD8+ T cells exhibiting comparable activation phenotypes during both infections. We observed T cells forming long-term cognate interactions with CX3CR1-bearing antigen presenting cells within the brains during P. berghei ANKA infection, but abrogation of this interaction by targeted depletion of the APC cells failed to prevent ECM development. Pathogenic CD8+ T cells were found to colocalize with rare apoptotic cells expressing CD31, a marker of endothelial cells, within the brain during ECM. However, cellular apoptosis was a rare event and did not result in loss of cerebral vasculature or correspond with the extensive disruption to its integrity observed during ECM. In summary, our data show that the arrest of T cells in the perivascular compartments of the brain is a unique signature of ECM-inducing malaria infection and implies an important role for this event in the development of the ECM-syndrome.

  2. CXCL4 and CXCL10 Predict Risk of Fatal Cerebral Malaria

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    Nana O. Wilson


    Full Text Available Plasmodium falciparum in a subset of patients can lead to a diffuse encephalopathy known as cerebral malaria (CM. Despite treatment, mortality caused by CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM involves alterations in cytokine and chemokine expression, local inflammation, vascular injury and repair processes. These diverse factors have limited the rate of discovery of prognostic predictors of fatal CM. Identification of reliable early predictors of CM severity will enable clinicians to adjust this risk with appropriate management of CM. Recent studies revealed that elevated levels of CXCL10 expression in cerebrospinal fluid and peripheral blood plasma independently predicted severe and fatal CM. CXCR3, a promiscuous receptor of CXCL10, plays an important role in pathogenesis of mouse model of CM. In this study the role of corresponding CXCR3 ligands (CXCL11, CXCL10, CXCL9 & CXCL4 in fatal or severe CM was evaluated by comparing their levels in 16 healthy control (HC, 26 mild malaria (MM, 26 cerebral malaria survivors (CMS and 12 non-survivors (CMNS using enzyme linked immunosorbent assay (ELISA. Levels of CXCL4 and CXCL10 were significantly elevated in CMNS patients (p < 0.05 when compared with HC, MM and CMS. Elevated plasma levels of CXCL10 and CXCL4 were tightly associated with CM mortality. Receiver Operating Characteristic (ROC curve analysis revealed that CXCL4 and CXCL10 can discriminate CMNS from MM (p < 0.0001 and CMS (p < 0.0001 with an area under the curve (AUC = 1. These results suggest that CXCL4 and CXCL10 play a prominent role in pathogenesis of CM associated death and may be used as functional or surrogate biomarkers for predicting CM severity.

  3. Differential PfEMP1 expression is associated with cerebral malaria pathology.

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    Dumizulu L Tembo


    Full Text Available Plasmodium falciparum is unique among human malarias in its ability to sequester in post-capillary venules of host organs. The main variant antigens implicated are the P. falciparum erythrocyte membrane protein 1 (PfEMP1, which can be divided into three major groups (A-C. Our study was a unique examination of sequestered populations of parasites for genetic background and expression of PfEMP1 groups. We collected post-mortem tissue from twenty paediatric hosts with pathologically different forms of cerebral malaria (CM1 and CM2 and parasitaemic controls (PC to directly examine sequestered populations of parasites in the brain, heart and gut. Use of two different techniques to investigate this question produced divergent results. By quantitative PCR, group A var genes were upregulated in all three organs of CM2 and PC cases. In contrast, in CM1 infections displaying high levels of sequestration but negligible vascular pathology, there was high expression of group B var. Cloning and sequencing of var transcript tags from the same samples indicated a uniformly low expression of group A-like var. Generally, within an organ sample, 1-2 sequences were expressed at dominant levels. 23% of var tags were detected in multiple patients despite the P. falciparum infections being genetically distinct, and two tags were observed in up to seven hosts each with high expression in the brains of 3-4 patients. This study is a novel examination of the sequestered parasites responsible for fatal cerebral malaria and describes expression patterns of the major cytoadherence ligand in three organ-derived populations and three pathological states.

  4. Vß profiles in African children with acute cerebral or uncomplicated malaria: very focused changes among a remarkable global stability

    DEFF Research Database (Denmark)

    Loizon, Séverine; Boeuf, Philippe; Tetteh, John K A


    T cells are thought to play a critical role in cerebral malaria pathogenesis. However, available evidences are restricted to rodent models in which V beta specific T cell expansion has been associated with neurological syndrome suggesting involvement of superantigens or dominant antigens. Using f...

  5. The contribution of natural killer complex loci to the development of experimental cerebral malaria.

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    Diana S Hansen

    Full Text Available The Natural Killer Complex (NKC is a genetic region of highly linked genes encoding several receptors involved in the control of NK cell function. The NKC is highly polymorphic and allelic variability of various NKC loci has been demonstrated in inbred mice, providing evidence for NKC haplotypes. Using BALB.B6-Cmv1r congenic mice, in which NKC genes from C57BL/6 mice were introduced into the BALB/c background, we have previously shown that the NKC is a genetic determinant of malarial pathogenesis. C57BL/6 alleles are associated with increased disease-susceptibility as BALB.B6-Cmv1r congenic mice had increased cerebral pathology and death rates during P. berghei ANKA infection than cerebral malaria-resistant BALB/c controls.To investigate which regions of the NKC are involved in susceptibility to experimental cerebral malaria (ECM, intra-NKC congenic mice generated by backcrossing recombinant F2 progeny from a (BALB/c x BALB.B6-Cmv1r F1 intercross to BALB/c mice were infected with P. berghei ANKA.Our results revealed that C57BL/6 alleles at two locations in the NKC contribute to the development of ECM. The increased severity to severe disease in intra-NKC congenic mice was not associated with higher parasite burdens but correlated with a significantly enhanced systemic IFN-γ response to infection and an increased recruitment of CD8+ T cells to the brain of infected animals.Polymorphisms within the NKC modulate malarial pathogenesis and acquired immune responses to infection.

  6. Brain mitochondrial function in a murine model of cerebral malaria and the therapeutic effects of rhEPO

    DEFF Research Database (Denmark)

    Karlsson, Michael; Hempel, Casper; Sjövall, Fredrik


    ; infected injected with saline or with rhEPO, non-infected injected with saline or with rhEPO. Infected mice developed CM and treatment with rhEPO attenuated clinical signs of disease. There were no differences in respiratory parameters of brain mitochondria between infected and non-infected mice......Cerebral malaria (CM) is a life-threatening complication of Plasmodium falciparum infection. The pathogenesis of CM is complex. Cerebral metabolic dysfunction is implicated in CM, which may be caused by both an impaired cerebral microcirculation and a dysregulated inflammatory response affecting...

  7. A rapid murine coma and behavior scale for quantitative assessment of murine cerebral malaria.

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    Ryan W Carroll

    Full Text Available BACKGROUND: Cerebral malaria (CM is a neurological syndrome that includes coma and seizures following malaria parasite infection. The pathophysiology is not fully understood and cannot be accounted for by infection alone: patients still succumb to CM, even if the underlying parasite infection has resolved. To that effect, there is no known adjuvant therapy for CM. Current murine CM (MCM models do not allow for rapid clinical identification of affected animals following infection. An animal model that more closely mimics the clinical features of human CM would be helpful in elucidating potential mechanisms of disease pathogenesis and evaluating new adjuvant therapies. METHODOLOGY/PRINCIPAL FINDINGS: A quantitative, rapid murine coma and behavior scale (RMCBS comprised of 10 parameters was developed to assess MCM manifested in C57BL/6 mice infected with Plasmodium berghei ANKA (PbA. Using this method a single mouse can be completely assessed within 3 minutes. The RMCBS enables the operator to follow the evolution of the clinical syndrome, validated here by correlations with intracerebral hemorrhages. It provides a tool by which subjects can be identified as symptomatic prior to the initiation of trial treatment. CONCLUSIONS/SIGNIFICANCE: Since the RMCBS enables an operator to rapidly follow the course of disease, label a subject as affected or not, and correlate the level of illness with neuropathologic injury, it can ultimately be used to guide the initiation of treatment after the onset of cerebral disease (thus emulating the situation in the field. The RMCBS is a tool by which an adjuvant therapy can be objectively assessed.

  8. Plasmodium Berghei ANKA Infection in ICR Mice as a Model of Cerebral Malaria

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    F Othman


    Full Text Available Background: Animal models with various combination of host-parasite have long been employed to study malaria pathogenesis. Here, we describe the combination of Plasmodium berghei ANKA infec­tion in inbred ICR mice as a model of cerebral malaria (CM.Methods: Infection in mice was initiated by intraperitoneal injection of 2 x 107 (0.2ml parasitized red blood cells (PRBCs.Results: This model can produce a severe degree of infection presented by the high degree of parasitae­mia followed by death 6-7 days post infection. Severe anemia, splenomegaly, hepatomegaly and discolourations of major organs were observed. Histopathological findings revealed several impor­tant features mimicking human CM including, microvascular sequestration of PRBCs in major organs, particularly in the brain, hypertrophy and hyperplasia of the kupffer cells in the liver, pulmo­nary edema and hyaline membrane formation in the lungs and haemorrhages in the kidney’s medulla and cortex. Proinflammatory cytokines TNFα, IFNγ, IL-1, IL-6 and IL-18, and anti-inflammatory cytokine IL-10 were all found to be elevated in the plasma of infected mice.Conclusion: This model can reproduce many of the important features of CM and therefore can be used as a tool to advance our understanding of the disease pathogenesis.

  9. Inhibition of endothelial activation: a new way to treat cerebral malaria?

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    Full Text Available BACKGROUND: Malaria is still a major public health problem, partly because the pathogenesis of its major complication, cerebral malaria (CM, remains incompletely understood. However tumor necrosis factor (TNF is thought to play a key role in the development of this neurological syndrome, as well as lymphotoxin alpha (LT. METHODS AND FINDINGS: Using an in vitro model of CM based on human brain-derived endothelial cells (HBEC-5i, we demonstrate the anti-inflammatory effect of LMP-420, a 2-NH2-6-Cl-9-[(5-dihydroxyboryl-pentyl] purine that is a transcriptional inhibitor of TNF. When added before or concomitantly to TNF, LMP-420 inhibits endothelial cell (EC activation, i.e., the up-regulation of both ICAM-1 and VCAM-1 on HBEC-5i surfaces. Subsequently, LMP-420 abolishes the cytoadherence of ICAM-1-specific Plasmodium falciparum-parasitized red blood cells on these EC. Identical but weaker effects are observed when LMP-420 is added with LT. LMP-420 also causes a dramatic reduction of HBEC-5i vesiculation induced by TNF or LT stimulation, as assessed by microparticle release. CONCLUSION: These data provide evidence for a strong in vitro anti-inflammatory effect of LMP-420 and suggest that targeting host cell pathogenic mechanisms might provide a new therapeutic approach to improving the outcome of CM patients.

  10. Cerebrospinal fluid and serum biomarkers of cerebral malaria mortality in Ghanaian children

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    Wiredu Edwin K


    Full Text Available Abstract Background Plasmodium falciparum can cause a diffuse encephalopathy known as cerebral malaria (CM, a major contributor to malaria associated mortality. Despite treatment, mortality due to CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM and other forms of severe malaria is multi-factorial and appear to involve cytokine and chemokine homeostasis, inflammation and vascular injury/repair. Identification of prognostic markers that can predict CM severity will enable development of better intervention. Methods Postmortem serum and cerebrospinal fluid (CSF samples were obtained within 2–4 hours of death in Ghanaian children dying of CM, severe malarial anemia (SMA, and non-malarial (NM causes. Serum and CSF levels of 36 different biomarkers (IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70, IL-13, IL-15, IL-17, Eotaxin, FGF basic protein, CRP, G-CSF, GM-CSF, IFN-γ, TNF-α, IP-10, MCP-1 (MCAF, MIP-1α, MIP-1β, RANTES, SDF-1α, CXCL11 (I-TAC, Fas-ligand [Fas-L], soluble Fas [sFas], sTNF-R1 (p55, sTNF-R2 (p75, MMP-9, TGF-β1, PDGF bb and VEGF were measured and the results compared between the 3 groups. Results After Bonferroni adjustment for other biomarkers, IP-10 was the only serum biomarker independently associated with CM mortality when compared to SMA and NM deaths. Eight CSF biomarkers (IL-1ra, IL-8, IP-10, PDGFbb, MIP-1β, Fas-L, sTNF-R1, and sTNF-R2 were significantly elevated in CM mortality group when compared to SMA and NM deaths. Additionally, CSF IP-10/PDGFbb median ratio was statistically significantly higher in the CM group compared to SMA and NM groups. Conclusion The parasite-induced local cerebral dysregulation in the production of IP-10, 1L-8, MIP-1β, PDGFbb, IL-1ra, Fas-L, sTNF-R1, and sTNF-R2 may be involved in CM neuropathology, and their immunoassay may have potential utility in predicting

  11. Production, fate and pathogenicity of plasma microparticles in murine cerebral malaria.

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    Fatima El-Assaad


    Full Text Available In patients with cerebral malaria (CM, higher levels of cell-specific microparticles (MP correlate with the presence of neurological symptoms. MP are submicron plasma membrane-derived vesicles that express antigens of their cell of origin and phosphatidylserine (PS on their surface, facilitating their role in coagulation, inflammation and cell adhesion. In this study, the in vivo production, fate and pathogenicity of cell-specific MP during Plasmodium berghei infection of mice were evaluated. Using annexin V, a PS ligand, and flow cytometry, analysis of platelet-free plasma from infected mice with cerebral involvement showed a peak of MP levels at the time of the neurological onset. Phenotypic analyses showed that MP from infected mice were predominantly of platelet, endothelial and erythrocytic origins. To determine the in vivo fate of MP, we adoptively transferred fluorescently labelled MP from mice with CM into healthy or infected recipient mice. MP were quickly cleared following intravenous injection, but microscopic examination revealed arrested MP lining the endothelium of brain vessels of infected, but not healthy, recipient mice. To determine the pathogenicity of MP, we transferred MP from activated endothelial cells into healthy recipient mice and this induced CM-like brain and lung pathology. This study supports a pathogenic role for MP in the aggravation of the neurological lesion and suggests a causal relationship between MP and the development of CM.

  12. Heme Oxygenase-1 and Breast Cancer Resistance Protein Protect Against Heme-induced Toxicity

    NARCIS (Netherlands)

    Wagener, F.A.D.T.G.; Dankers, A.C.A.; Summeren, F. van; Scharstuhl, A.; Heuvel, J.J. van den; Koenderink, J.B.; Pennings, S.W.C.; Russel, F.G.M.; Masereeuw, R.


    Heme is the functional group of diverse hemoproteins and crucial for many cellular processes. However, heme is increasingly recognized as a culprit for a wide variety of pathologies, including sepsis, malaria, and kidney failure. Excess of free heme can be detrimental to tissues by mediating oxidati

  13. Ten years experience with 497 cases of neuroinfections in tropic: in limited laboratory infrastructure initially treat both, cerebral malaria and meningitis. (United States)

    Benca, J; Ondrusova, A; Adamcova, J; Takacova, M; Polonova, J; Taziarova, M


    Review of 497 cases of neuroinfections in 7 tropical clinics in Ethiopia, Uganda, Burundi, Kenya, Sudan within 2000-2007 was performed. 97.5% of all cases was cerebral malaria (40.1%) and bacterial meningitis (56.4%). TB meningitis, cerebral cryptococcosis and sleeping sickness were very rare.

  14. Reduction of Experimental Cerebral Malaria and Its Related Proinflammatory Responses by the Novel Liposome-Based β-Methasone Nanodrug

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    Jintao Guo


    Full Text Available Cerebral malaria (CM is a severe complication of and a leading cause of death due to Plasmodium falciparum infection. CM is likely the result of interrelated events, including mechanical obstruction due to parasite sequestration in the microvasculature, and upregulation of Th1 immune responses. In parallel, blood-brain-barrier (BBB breakdown and damage or death of microglia, astrocytes, and neurons occurs. We found that a novel formulation of a liposome-encapsulated glucocorticosteroid, β-methasone hemisuccinate (nSSL-BMS, prevents experimental cerebral malaria (ECM in a murine model and creates a survival time-window, enabling administration of an antiplasmodial drug before severe anemia develops. nSSL-BMS treatment leads to lower levels of cerebral inflammation, expressed by altered levels of corresponding cytokines and chemokines. The results indicate the role of integrated immune responses in ECM induction and show that the new steroidal nanodrug nSSL-BMS reverses the balance between the Th1 and Th2 responses in malaria-infected mice so that the proinflammatory processes leading to ECM are prevented. Overall, because of the immunopathological nature of CM, combined immunomodulator/antiplasmodial treatment should be considered for prevention/treatment of human CM and long-term cognitive damage.

  15. Activation of calpains, calpastatin and spectrin cleavage in the brain during the pathology of fatal murine cerebral malaria. (United States)

    Shukla, Meena; Rajgopal, Yadavalli; Babu, Phanithi Prakash


    Neuronal calpains appear to be activated uncontrollably by sustained elevation of cytosolic calcium levels under pathological conditions as well as neurodegenerative diseases. In the present study, we have characterized calpain activation in cytosolic extract of mice cerebral cortex and cerebellum using an experimental model of fatal murine cerebral malaria (FMCM). Pathology of FMCM resulted in the increase in activity of calpains in both cerebral cortex and cerebellum. Western blot analysis revealed an increase in the levels of mu-calpain (calpain-1) in the cytosolic fraction of infected cerebral cortex and cerebellum although a decrease in the level of m-calpain was observed in the cytosolic fraction of infected cerebellum and cerebral cortex. Calpain activation was further confirmed by monitoring the formation of calpain-specific spectrin breakdown products (SBDP). Protease-specific SBDP revealed the formation of calpain-generated 150kDa product in the infected cerebral cortex and cerebellum. The specific signature fragment of calpain activation and spectrin breakdown after Plasmodium berghei ANKA infection provide a strong evidence of the role of calpains during the cell death in cerebral cortex and cerebellum. Given the role of calpains in neurodegeneration and cell death, our results strongly suggest that calpains are important mediators of cell injury and neurological sequelae associated with FMCM.

  16. Differential kinetics of plasma procalcitonin levels in cerebral malaria in urban Senegalese patients according to disease outcome

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    Babacar Mbengue


    Full Text Available P. falciparum malaria continues as the serial killer of over a million lives yearly, mainly for children in sub-Saharan Africa. For severe malaria, we are still on the quest for a prognostic marker of fatal outcome. We analysed the association between serum levels of Procalcitonin (PCT, a marker of septic inflammation, and clinical outcome in Senegalese patients admitted with confirmed cerebral malaria in the intensive care facility of Hopital Principal. A total of 98 patients living in the hypoendemic urban area of Dakar, Senegal, were enrolled during transmission seasons. Levels of PCT were compared between surviving vs the 26.5 % fatal cases in blood samples of the 3 days following hospitalisation. Mean PCT levels were elevated in patients with active infection, with a large range of values (0.1 to 280 nanog per mL, significantly higher on day 0 in fatal cases than in surviving (53.6 vs 27.3; P=0.01. No exact individual threshold level could indicate occurrence of fatality, however mortality could be most accurately predicted by PCT level above 69 nanog per ML and there was a very clear different profile of evolution of PCT levels on the 3 days of observation decreasing early from day 1 in surviving patients (P<10–3, contrary to fatal cases. These results indicate that PCT kinetic rather than intrinsic level could be of use to predict a reduced risk of fatality in patient with cerebral malaria and could serve as potential predicting marker for severe malaria.

  17. Phosphatidylinositol 3-Kinase γ is required for the development of experimental cerebral malaria.

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    Norinne Lacerda-Queiroz

    Full Text Available Experimental cerebral malaria (ECM is characterized by a strong immune response, with leukocyte recruitment, blood-brain barrier breakdown and hemorrhage in the central nervous system. Phosphatidylinositol 3-kinase γ (PI3Kγ is central in signaling diverse cellular functions. Using PI3Kγ-deficient mice (PI3Kγ-/- and a specific PI3Kγ inhibitor, we investigated the relevance of PI3Kγ for the outcome and the neuroinflammatory process triggered by Plasmodium berghei ANKA (PbA infection. Infected PI3Kγ-/- mice had greater survival despite similar parasitemia levels in comparison with infected wild type mice. Histopathological analysis demonstrated reduced hemorrhage, leukocyte accumulation and vascular obstruction in the brain of infected PI3Kγ-/- mice. PI3Kγ deficiency also presented lower microglial activation (Iba-1+ reactive microglia and T cell cytotoxicity (Granzyme B expression in the brain. Additionally, on day 6 post-infection, CD3+CD8+ T cells were significantly reduced in the brain of infected PI3Kγ-/- mice when compared to infected wild type mice. Furthermore, expression of CD44 in CD8+ T cell population in the brain tissue and levels of phospho-IkB-α in the whole brain were also markedly lower in infected PI3Kγ-/- mice when compared with infected wild type mice. Finally, AS605240, a specific PI3Kγ inhibitor, significantly delayed lethality in infected wild type mice. In brief, our results indicate a pivotal role for PI3Kγ in the pathogenesis of ECM.

  18. Glucocorticosteroids in nano-sterically stabilized liposomes are efficacious for elimination of the acute symptoms of experimental cerebral malaria. (United States)

    Waknine-Grinberg, Judith H; Even-Chen, Simcha; Avichzer, Jasmine; Turjeman, Keren; Bentura-Marciano, Annael; Haynes, Richard K; Weiss, Lola; Allon, Nahum; Ovadia, Haim; Golenser, Jacob; Barenholz, Yechezkel


    Cerebral malaria is the most severe complication of Plasmodium falciparum infection, and a leading cause of death in children under the age of five in malaria-endemic areas. We report high therapeutic efficacy of a novel formulation of liposome-encapsulated water-soluble glucocorticoid prodrugs, and in particular β-methasone hemisuccinate (BMS), for treatment of experimental cerebral malaria (ECM), using the murine P. berghei ANKA model. BMS is a novel derivative of the potent steroid β-methasone, and was specially synthesized to enable remote loading into nano-sterically stabilized liposomes (nSSL), to form nSSL-BMS. The novel nano-drug, composed of nSSL remote loaded with BMS, dramatically improves drug efficacy and abolishes the high toxicity seen upon administration of free BMS. nSSL-BMS reduces ECM rates in a dose-dependent manner and creates a survival time-window, enabling administration of an antiplasmodial drug, such as artemisone. Administration of artemisone after treatment with the nSSL-BMS results in complete cure. Treatment with BMS leads to lower levels of cerebral inflammation, demonstrated by changes in cytokines, chemokines, and cell markers, as well as diminished hemorrhage and edema, correlating with reduced clinical score. Administration of the liposomal formulation results in accumulation of BMS in the brains of sick mice but not of healthy mice. This steroidal nano-drug effectively eliminates the adverse effects of the cerebral syndrome even when the treatment is started at late stages of disease, in which disruption of the blood-brain barrier has occurred and mice show clear signs of neurological impairment. Overall, sequential treatment with nSSL-BMS and artemisone may be an efficacious and well-tolerated therapy for prevention of CM, elimination of parasites, and prevention of long-term cognitive damage.

  19. Malaria. (United States)

    Heck, J E


    Human malaria is caused by four species of the genus plasmodium. The sexual stage of the parasite occurs in the mosquito and asexual reproduction occurs in man. Symptoms of fever, chills, headache, and myalgia result from the invasion and rupture of erythrocytes. Merozoites are released from erythrocytes and invade other cells, thus propagating the infection. The most vulnerable hosts are nonimmune travelers, young children living in the tropics, and pregnant women. P. falciparum causes the most severe infections because it infects RBCs of all ages and has the propensity to develop resistance to antimalarials. Rapid diagnosis can be made with a malarial smear, and treatment should be initiated promptly. In some regions (Mexico, Central America except Panama, and North Africa) chloroquine phosphate is effective therapy. In subsaharan Africa, South America, and Southeast Asia, chloroquine resistance has become widespread, and other antimalarials are necessary. The primary care physician should have a high index of suspicion for malaria in the traveler returning from the tropics. Malaria should also be suspected in the febrile transfusion recipient and newborns of mothers with malaria.

  20. Automated Detection of Malarial Retinopathy in Digital Fundus Images for Improved Diagnosis in Malawian Children with Clinically Defined Cerebral Malaria (United States)

    Joshi, Vinayak; Agurto, Carla; Barriga, Simon; Nemeth, Sheila; Soliz, Peter; MacCormick, Ian J.; Lewallen, Susan; Taylor, Terrie E.; Harding, Simon P.


    Cerebral malaria (CM), a complication of malaria infection, is the cause of the majority of malaria-associated deaths in African children. The standard clinical case definition for CM misclassifies ~25% of patients, but when malarial retinopathy (MR) is added to the clinical case definition, the specificity improves from 61% to 95%. Ocular fundoscopy requires expensive equipment and technical expertise not often available in malaria endemic settings, so we developed an automated software system to analyze retinal color images for MR lesions: retinal whitening, vessel discoloration, and white-centered hemorrhages. The individual lesion detection algorithms were combined using a partial least square classifier to determine the presence or absence of MR. We used a retrospective retinal image dataset of 86 pediatric patients with clinically defined CM (70 with MR and 16 without) to evaluate the algorithm performance. Our goal was to reduce the false positive rate of CM diagnosis, and so the algorithms were tuned at high specificity. This yielded sensitivity/specificity of 95%/100% for the detection of MR overall, and 65%/94% for retinal whitening, 62%/100% for vessel discoloration, and 73%/96% for hemorrhages. This automated system for detecting MR using retinal color images has the potential to improve the accuracy of CM diagnosis.

  1. Heme on innate immunity and inflammation

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    Fabianno Ferreira Dutra


    Full Text Available Heme is an essential molecule expressed ubiquitously all through our tissues. Heme plays major functions in cellular physiology and metabolism as the prostetic group of diverse proteins. Once released from cells and from hemeproteins free heme causes oxidative damage and inflammation, thus acting as a prototypic damage-associated molecular pattern. In this context, free heme is a critical component of the pathological process of sterile and infectious hemolytic conditions including malaria, hemolytic anemias, ischemia-reperfusion and hemorrhage. The plasma scavanger proteins hemopexin and albumin reduce heme toxicity and are responsible for transporting free heme to intracellular compartments where it is catabolized by heme-oxygenase enzymes. Upon hemolysis or severe cellular damage the serum capacity to scavange heme may saturate and increase free heme to sufficient amounts to cause tissue damage in various organs. The mechanism by which heme causes reactive oxygen generation, activation of cells of the innate immune system and cell death are not fully understood. Although heme can directly promote lipid peroxidation by its iron atom, heme can also induce ROS generation and production of inflammatory mediators through the activation of selective signaling pathways. Heme activates innate immune cells such as macrophages and neutrophils through activation of innate immune receptors. The importance of these events has been demonstrated in infectious and non-infectious diseases models. In this review we will discuss the mechanisms behind heme-induced citotoxicity and inflammation and the consequences of these events on different tissues and diseases.

  2. Malaria (United States)


    glands , and are inoculated into host during subsequent blood meal. 7. In human host, sporozoites leave blood and infect hepatocytes. 8-10...reach the mosquito’s salivary glands lodge there and are inoculated into a new host when the mosquito takes an- other blood meal. In humans...from 53-year-old patient who died of chloroquine-resistant falciparum malaria. x600 Figure 10.77 Mature schizont (arrow) in capillary in parathyroid

  3. Emergency caesarean delivery in a patient with cerebral malaria-leptospira co infection: Anaesthetic and critical care considerations

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    Sukhen Samanta


    Full Text Available Malaria-leptospira co-infection is rarely detected. Emergency surgery in such patients has not been reported. We describe such a case of a 24-year-old primigravida at term pregnancy posted for emergency caesarean delivery who developed pulmonary haemorrhage, acute respiratory distress syndrome, acute kidney injury, and cerebral oedema. Here, we discuss the perioperative management, pain management (with transverse abdominis plane block, intensive care management (special reference to management of pulmonary haemorrhage with intra pulmonary factor VIIa and the role of plasmapheresis in leptospira related jaundice with renal failure.

  4. Cannabidiol increases survival and promotes rescue of cognitive function in a murine model of cerebral malaria. (United States)

    Campos, A C; Brant, F; Miranda, A S; Machado, F S; Teixeira, A L


    Cerebral malaria (CM) is a severe complication resulting from Plasmodium falciparum infection that might cause permanent neurological deficits. Cannabidiol (CBD) is a nonpsychotomimetic compound of Cannabis sativa with neuroprotective properties. In the present work, we evaluated the effects of CBD in a murine model of CM. Female mice were infected with Plasmodium berghei ANKA (PbA) and treated with CBD (30mg/kg/day - 3 or 7days i.p.) or vehicle. On 5th day-post-infection (dpi), at the peak of the disease), animals were treated with single or repeated doses of Artesunate, an antimalarial drug. All groups were tested for memory impairment (Novel Object Recognition or Morris Water Maze) and anxiety-like behaviors (Open field or elevated plus maze test) in different stages of the disease (at the peak or after the complete clearance of the disease). Th1/Th2 cytokines and neurotrophins (brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF)) were measured in the prefrontal cortex and hippocampus of experimental groups. PbA-infected mice displayed memory deficits and exhibited increase in anxiety-like behaviors on the 5dpi or after the clearance of the parasitemia, effects prevented by CBD treatment. On 5dpi, TNF-α and IL-6 increased in the hippocampus, while only IL-6 increased in the prefrontal cortex. CBD treatment resulted in an increase in BDNF expression in the hippocampus and decreased levels of proinflammatory cytokines in the hippocampus (TNF-α) and prefrontal cortex (IL-6). Our results indicate that CBD exhibits neuroprotective effects in CM model and might be useful as an adjunctive therapy to prevent neurological symptoms following this disease.

  5. Specific depletion of Ly6C(hi inflammatory monocytes prevents immunopathology in experimental cerebral malaria.

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    Beatrix Schumak

    Full Text Available Plasmodium berghei ANKA (PbA infection of C57BL/6 mice leads to experimental cerebral malaria (ECM that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb, we depleted in vivo Ly6C(hi inflammatory monocytes (by anti-CCR2, Ly6G+ neutrophils (by anti-Ly6G or both cell types (by anti-Gr1 during infection with Ovalbumin-transgenic PbA parasites (PbTg. Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6C(hi inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6C(hi inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes.

  6. Increased concentrations of interleukin-6 and interleukin-1 receptor antagonist and decreased concentrations of beta-2-glycoprotein I in Gambian children with cerebral malaria

    DEFF Research Database (Denmark)

    Jakobsen, P H; McKay, V; Morris-Jones, S D;


    concentrations of anti-PI antibodies and the PI-binding serum protein beta-2-glycoprotein I. We found increased concentrations of IL-6, sIL-6R, IL-1ra, and some immunoglobulin M antibodies against PI in children with cerebral malaria, but those who died had decreased concentrations of beta-2-glycoprotein I. We...... conclude that increased concentrations of cytokines and soluble cytokine receptors represent a normal host response to P. falciparum infections but that excessive secretion of cytokines like IL-6 may predispose to cerebral malaria and a fatal outcome while beta-2-glycoprotein I may protect against a fatal...

  7. Characterisation of the opposing effects of G6PD deficiency on cerebral malaria and severe malarial anaemia (United States)

    Clarke, Geraldine M; Rockett, Kirk; Kivinen, Katja; Hubbart, Christina; Jeffreys, Anna E; Rowlands, Kate; Jallow, Muminatou; Conway, David J; Bojang, Kalifa A; Pinder, Margaret; Usen, Stanley; Sisay-Joof, Fatoumatta; Sirugo, Giorgio; Toure, Ousmane; Thera, Mahamadou A; Konate, Salimata; Sissoko, Sibiry; Niangaly, Amadou; Poudiougou, Belco; Mangano, Valentina D; Bougouma, Edith C; Sirima, Sodiomon B; Modiano, David; Amenga-Etego, Lucas N; Ghansah, Anita; Koram, Kwadwo A; Wilson, Michael D; Enimil, Anthony; Evans, Jennifer; Amodu, Olukemi K; Olaniyan, Subulade; Apinjoh, Tobias; Mugri, Regina; Ndi, Andre; Ndila, Carolyne M; Uyoga, Sophie; Macharia, Alexander; Peshu, Norbert; Williams, Thomas N; Manjurano, Alphaxard; Sepúlveda, Nuno; Clark, Taane G; Riley, Eleanor; Drakeley, Chris; Reyburn, Hugh; Nyirongo, Vysaul; Kachala, David; Molyneux, Malcolm; Dunstan, Sarah J; Phu, Nguyen Hoan; Quyen, Nguyen Ngoc; Thai, Cao Quang; Hien, Tran Tinh; Manning, Laurens; Laman, Moses; Siba, Peter; Karunajeewa, Harin; Allen, Steve; Allen, Angela; Davis, Timothy ME; Michon, Pascal; Mueller, Ivo; Molloy, Síle F; Campino, Susana; Kerasidou, Angeliki; Cornelius, Victoria J; Hart, Lee; Shah, Shivang S; Band, Gavin; Spencer, Chris CA; Agbenyega, Tsiri; Achidi, Eric; Doumbo, Ogobara K; Farrar, Jeremy; Marsh, Kevin; Taylor, Terrie; Kwiatkowski, Dominic P


    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is believed to confer protection against Plasmodium falciparum malaria, but the precise nature of the protective effect has proved difficult to define as G6PD deficiency has multiple allelic variants with different effects in males and females, and it has heterogeneous effects on the clinical outcome of P. falciparum infection. Here we report an analysis of multiple allelic forms of G6PD deficiency in a large multi-centre case-control study of severe malaria, using the WHO classification of G6PD mutations to estimate each individual’s level of enzyme activity from their genotype. Aggregated across all genotypes, we find that increasing levels of G6PD deficiency are associated with decreasing risk of cerebral malaria, but with increased risk of severe malarial anaemia. Models of balancing selection based on these findings indicate that an evolutionary trade-off between different clinical outcomes of P. falciparum infection could have been a major cause of the high levels of G6PD polymorphism seen in human populations. DOI: PMID:28067620

  8. The plant-based immunomodulator curcumin as a potential candidate for the development of an adjunctive therapy for cerebral malaria

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    Taramelli Donatella


    Full Text Available Abstract The clinical manifestations of cerebral malaria (CM are well correlated with underlying major pathophysiological events occurring during an acute malaria infection, the most important of which, is the adherence of parasitized erythrocytes to endothelial cells ultimately leading to sequestration and obstruction of brain capillaries. The consequent reduction in blood flow, leads to cerebral hypoxia, localized inflammation and release of neurotoxic molecules and inflammatory cytokines by the endothelium. The pharmacological regulation of these immunopathological processes by immunomodulatory molecules may potentially benefit the management of this severe complication. Adjunctive therapy of CM patients with an appropriate immunomodulatory compound possessing even moderate anti-malarial activity with the capacity to down regulate excess production of proinflammatory cytokines and expression of adhesion molecules, could potentially reverse cytoadherence, improve survival and prevent neurological sequelae. Current major drug discovery programmes are mainly focused on novel parasite targets and mechanisms of action. However, the discovery of compounds targeting the host remains a largely unexplored but attractive area of drug discovery research for the treatment of CM. This review discusses the properties of the plant immune-modifier curcumin and its potential as an adjunctive therapy for the management of this complication.

  9. Endothelium-based biomarkers are associated with cerebral malaria in Malawian children: a retrospective case-control study.

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    Andrea L Conroy

    Full Text Available BACKGROUND: Differentiating cerebral malaria (CM from other causes of serious illness in African children is problematic, owing to the non-specific nature of the clinical presentation and the high prevalence of incidental parasitaemia. CM is associated with endothelial activation. In this study we tested the hypothesis that endothelium-derived biomarkers are associated with the pathophysiology of severe malaria and may help identify children with CM. METHODS AND FINDINGS: Plasma samples were tested from children recruited with uncomplicated malaria (UM; n = 32, cerebral malaria with retinopathy (CM-R; n = 38, clinically defined CM without retinopathy (CM-N; n = 29, or non-malaria febrile illness with decreased consciousness (CNS; n = 24. Admission levels of angiopoietin-2 (Ang-2, Ang-1, soluble Tie-2 (sTie-2, von Willebrand factor (VWF, its propeptide (VWFpp, vascular endothelial growth factor (VEGF, soluble ICAM-1 (sICAM-1 and interferon-inducible protein 10 (IP-10 were measured by ELISA. Children with CM-R had significantly higher median levels of Ang-2, Ang-2:Ang-1, sTie-2, VWFpp and sICAM-1 compared to children with CM-N. Children with CM-R had significantly lower median levels of Ang-1 and higher median concentrations of Ang-2:Ang-1, sTie-2, VWF, VWFpp, VEGF and sICAM-1 compared to UM, and significantly lower median levels of Ang-1 and higher median levels of Ang-2, Ang-2:Ang-1, VWF and VWFpp compared to children with fever and altered consciousness due to other causes. Ang-1 was the best discriminator between UM and CM-R and between CNS and CM-R (areas under the ROC curve of 0.96 and 0.93, respectively. A comparison of biomarker levels in CM-R between admission and recovery showed uniform increases in Ang-1 levels, suggesting this biomarker may have utility in monitoring clinical response. CONCLUSIONS: These results suggest that endothelial proteins are informative biomarkers of malarial disease severity. These results

  10. Cognitive dysfunction is sustained after rescue therapy in experimental cerebral malaria, and is reduced by additive antioxidant therapy.

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    Patricia A Reis

    Full Text Available Neurological impairments are frequently detected in children surviving cerebral malaria (CM, the most severe neurological complication of infection with Plasmodium falciparum. The pathophysiology and therapy of long lasting cognitive deficits in malaria patients after treatment of the parasitic disease is a critical area of investigation. In the present study we used several models of experimental malaria with differential features to investigate persistent cognitive damage after rescue treatment. Infection of C57BL/6 and Swiss (SW mice with Plasmodium berghei ANKA (PbA or a lethal strain of Plasmodium yoelii XL (PyXL, respectively, resulted in documented CM and sustained persistent cognitive damage detected by a battery of behavioral tests after cure of the acute parasitic disease with chloroquine therapy. Strikingly, cognitive impairment was still present 30 days after the initial infection. In contrast, BALB/c mice infected with PbA, C57BL6 infected with Plasmodium chabaudi chabaudi and SW infected with non lethal Plasmodium yoelii NXL (PyNXL did not develop signs of CM, were cured of the acute parasitic infection by chloroquine, and showed no persistent cognitive impairment. Reactive oxygen species have been reported to mediate neurological injury in CM. Increased production of malondialdehyde (MDA and conjugated dienes was detected in the brains of PbA-infected C57BL/6 mice with CM, indicating high oxidative stress. Treatment of PbA-infected C57BL/6 mice with additive antioxidants together with chloroquine at the first signs of CM prevented the development of persistent cognitive damage. These studies provide new insights into the natural history of cognitive dysfunction after rescue therapy for CM that may have clinical relevance, and may also be relevant to cerebral sequelae of sepsis and other disorders.

  11. A functional polymorphism in the IL1B gene promoter, IL1B -31C>T, is not associated with cerebral malaria in Thailand


    Tangpukdee Noppadon; Hananantachai Hathairad; Patarapotikul Jintana; Doi Akihiro; Naka Izumi; Ohashi Jun; Looareesuwan Sornchai; Tokunaga Katsushi


    Abstract Background IL-1β and IL-1RA levels are higher in the serum of cerebral malaria patients than in patients with mild malaria. Recently, the level of IL1B expression was reported to be influenced by a polymorphism in the promoter of IL1, IL1B -31C>T. Methods To examine whether polymorphisms in IL1B and IL1RA influence the susceptibility to cerebral malaria, IL1B -31C>T, IL1B 3953C>T, and IL1RA variable number of tandem repeat (VNTR) were analysed in 312 Thai patients with malaria (109 c...

  12. Perforin expression by CD8 T cells is sufficient to cause fatal brain edema during experimental cerebral malaria. (United States)

    Huggins, Matthew; Johnson, Holly L; Jin, Fang; N'Songo, Aurelie; Hanson, Lisa M; LaFrance, Stephanie J; Butler, Noah S; Harty, John T; Johnson, Aaron J


    Human cerebral malaria (HCM) is a serious complication of Plasmodium falciparum infection. The most severe outcomes for patients include coma, permanent neurological deficits, and death. Recently, a large-scale magnetic resonance imaging (MRI) study in humans identified brain swelling as the most prominent predictor of fatal HCM. Therefore, in this study we sought to define the mechanism controlling brain edema through the use of the murine experimental cerebral malaria (ECM) model. Specifically, we investigated the ability of CD8 T cells to initiate brain edema during ECM. We determined that areas of blood-brain barrier (BBB) permeability colocalized with a reduction of the cerebral endothelial cell tight junction proteins claudin-5 and occludin. Furthermore, through small animal MRI we analyzed edema and vascular leakage. Using gadolinium enhanced T1-weighted MRI we determined that vascular permeability is not homogeneous, but rather confined to specific regions of the brain. Our findings show that BBB permeability was localized within the brainstem, olfactory bulb, and lateral ventricle. Concurrently with the initiation of vascular permeability, T2-weighted MRI revealed edema and brain swelling. Importantly, ablation of the cytolytic effector molecule perforin fully protected against vascular permeability and edema. Furthermore, perforin production specifically by CD8 T cells was required to cause fatal edema during ECM. We propose that CD8 T cells initiate BBB breakdown through perforin mediated disruption of tight junctions. In turn, leakage from the vasculature into the parenchyma causes brain swelling and edema. This results in a breakdown of homeostatic maintenance that likely contributes to ECM pathology.

  13. Electron microscopic features of brain edema in rodent cerebral malaria in relation to glial fibrillary acidic protein expression. (United States)

    Ampawong, Sumate; Chaisri, Urai; Viriyavejakul, Parnpen; Nontprasert, Apichart; Grau, Georges E; Pongponratn, Emsri


    The mechanisms leading to cerebral malaria (CM) are not completely understood. Brain edema has been suggested as having an important role in experimental CM. In this study, CBA/CaH mice were infected with Plasmodium berghei ANKA blood-stage and when typical symptoms of CM developed on day 7, brain tissues were processed for electron-microscopic and immunohistochemical studies. The study demonstrated ultrastructural hallmarks of cerebral edema by perivascular edema and astroglial dilatation confirming existing evidence of vasogenic and cytogenic edema. This correlates closely with the clinical features of CM. An adaptive response of astrocytic activity, represented by increasing glial fibrillary acidic protein (GFAP) expression in the perivascular area and increasing numbers of large astrocyte clusters were predominately found in the CM mice. The presence of multivesicular and lamellar bodies indicates the severity of cerebral damage in experimental CM. Congestion of the microvessels with occluded white blood cells (WBCs), parasitized red blood cells (PRBCs) and platelets is also a crucial covariate role for CM pathogenesis.

  14. Simultaneous administration of vitamin A and DTP vaccine modulates the immune response in a murine cerebral malaria model

    DEFF Research Database (Denmark)

    Hein-Kristensen, L; Jørgensen, M J; Ravn, H


    The World Health Organisation recommends vitamin A supplementation (VAS) to children aged 6 months to 5 years in low-income countries, and for logistic reasons, this has been linked to routine childhood immunizations. Observational studies suggest that VAS given with diphtheria-tetanus-pertussis ......The World Health Organisation recommends vitamin A supplementation (VAS) to children aged 6 months to 5 years in low-income countries, and for logistic reasons, this has been linked to routine childhood immunizations. Observational studies suggest that VAS given with diphtheria......-tetanus-pertussis (DTP) vaccine may increase mortality from non-targeted diseases. We investigated the non-targeted effect of pretreatment with VAS and DTP vaccine in a murine model of experimental cerebral malaria. Our a priori hypothesis was that VAS/DTP would aggravate the infection. We found that the effect of VAS...

  15. Plasmodium berghei ANKA: erythropoietin activates neural stem cells in an experimental cerebral malaria model

    DEFF Research Database (Denmark)

    Core, Andrew; Hempel, Casper; Kurtzhals, Jørgen A L;


    Cerebral malaria (CM) causes substantial mortality and neurological sequelae in survivors, and no neuroprotective regimens are currently available for this condition. Erythropoietin (EPO) reduces neuropathology and improves survival in murine CM. Using the Plasmodium berghei model of CM, we...... investigated if EPO's neuroprotective effects include activation of endogenous neural stem cells (NSC). By using immunohistochemical markers of different NSC maturation stages, we show that EPO increased the number of nestin(+) cells in the dentate gyrus and in the sub-ventricular zone of the lateral...... ventricles, relative to control-treatment. 75% of the EPO-treated CM mice displayed migration as nestin(+) NSC. The NSC showed differentiation towards a neural cell lineage as shown by PSA-NCAM binding and NSC maturation and lineage commitment was significantly affected by exogenous EPO and by CM in the sub...

  16. Complement factors C1q, C3 and C5 in brain and serum of mice with cerebral malaria

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    Helbok Raimund


    Full Text Available Abstract Background The patho-mechanisms leading to brain damage due to cerebral malaria (CM are yet not fully understood. Immune-mediated and ischaemic mechanisms have been implicated. The role of complement factors C1q, C3 and C5 for the pathogenesis of CM were investigated in this study. Methods C57BL/6J mice were infected with Plasmodium berghei ANKA blood stages. The clinical severity of the disease was assessed by a battery of 40 standardized tests for evaluating neurological functions in mice. Brain homogenates and sera of mice with CM, infected animals without CM and non-infected control animals were analyzed for C1q, C3 and C5 up-regulation by Western blotting. Results Densitometric analysis of Western blots of brain homogenates yielded statistically significant differences in the levels of C1q and C5 in the analyzed groups. Correlation analysis showed a statistically significant association of C1q and C5 levels with the clinical severity of the disease. More severely affected animals showed higher levels of C1q and C5. No differences in complement levels were observed between frontal and caudal parts of the brain. Densitometric analysis of Western blot of sera yielded statistically lower levels of C1q in infected animals without CM compared to animals of the control group. Conclusion The current study provides direct evidence for up-regulation of complement factors C1q and C5 in the brains of animals with CM. Local complement up-regulation is a possible mechanism for brain damage in experimental cerebral malaria.

  17. Atorvastatin treatment is effective when used in combination with mefloquine in an experimental cerebral malaria murine model

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    Souraud Jean-Baptiste


    Full Text Available Abstract Background One of the major complications of Plasmodium falciparum infection is cerebral malaria (CM, which causes one million deaths worldwide each year, results in long-term neurological sequelae and the treatment for which is only partially effective. Statins are recognized to have an immunomodulatory action, attenuate sepsis and have a neuroprotective effect. Atorvastatin (AVA has shown in vitro anti-malarial activity and has improved the activity of mefloquine (MQ and quinine. Methods The efficiency of 40 mg/kg intraperitoneal AVA, alone or in association with MQ, was assessed in an experimental Plasmodium berghei ANKA rodent parasite model of CM and performed according to different therapeutic schemes. The effects on experimental CM were assessed through the evaluation of brain histopathological changes and neuronal apoptosis by TUNEL staining. Results AVA alone in the therapeutic scheme show no effect on survival, but the prophylactic scheme employing AVA associated with MQ, rather than MQ alone, led to a significant delay in mouse death and had an effect on the onset of CM symptoms and on the level of parasitaemia. Histopathological findings show a correlation between brain lesions and CM onset. A neuronal anti-apoptotic effect of AVA in the AVA + MQ combination was not shown. Conclusions The combination of AVA and MQ therapy led to a significant delay in mouse mortality. There were differences in the incidence, time to cerebral malaria and the level of parasitaemia when the drug combination was administered to mice. When used in combination with MQ, AVA had a relevant effect on the in vivo growth inhibition and clinical outcome of P. berghei ANKA-infected mice.

  18. Quantitation of brain edema and localisation of aquaporin 4 expression in relation to susceptibility to experimental cerebral malaria. (United States)

    Ampawong, Sumate; Combes, Valéry; Hunt, Nicholas H; Radford, Jane; Chan-Ling, Tailoi; Pongponratn, Emsri; Grau, Georges E R


    The pathogenic mechanisms underlying the occurrence of cerebral malaria (CM) are still incompletely understood but, clearly, cerebral complications may result from concomitant microvessel obstruction and inflammation. The extent to which brain edema contributes to pathology has not been investigated. Using the model of P. berghei ANKA infection, we compared brain microvessel morphology of CM-susceptible and CM-resistant mice. By quantitative planimetry, we provide evidence that CM is characterized by enlarged perivascular spaces (PVS). We show a dramatic aquaporin 4 (AQP4) upregulation, selectively at the level of astrocytic foot processes, in both CM and non-CM disease, but significantly more pronounced in mice with malarial-induced neurological syndrome. This suggests that a threshold of AQP4 expression is needed to lead to neurovascular pathology, a view that is supported by significantly higher levels in mice with clinically overt CM. Numbers of intravascular leukocytes significantly correlated with both PVS enlargement and AQP4 overexpression. Thus, brain edema could be a contributing factor in CM pathogenesis and AQP4, specifically in its astrocytic location, a key molecule in this mechanism. Since experimental CM is associated with substantial brain edema, it models paediatric CM better than the adult syndrome and it is tempting to evaluate AQP4 in the former context. If AQP4 changes are confirmed in human CM, it may represent a novel target for therapeutic intervention.

  19. Both functional LTbeta receptor and TNF receptor 2 are required for the development of experimental cerebral malaria.

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    Dieudonnée Togbe

    Full Text Available BACKGROUND: TNF-related lymphotoxin alpha (LTalpha is essential for the development of Plasmodium berghei ANKA (PbA-induced experimental cerebral malaria (ECM. The pathway involved has been attributed to TNFR2. Here we show a second arm of LTalpha-signaling essential for ECM development through LTbeta-R, receptor of LTalpha1beta2 heterotrimer. METHODOLOGY/PRINCIPAL FINDINGS: LTbetaR deficient mice did not develop the neurological signs seen in PbA induced ECM but died at three weeks with high parasitaemia and severe anemia like LTalphabeta deficient mice. Resistance of LTalphabeta or LTbetaR deficient mice correlated with unaltered cerebral microcirculation and absence of ischemia, as documented by magnetic resonance imaging and angiography, associated with lack of microvascular obstruction, while wild-type mice developed distinct microvascular pathology. Recruitment and activation of perforin(+ CD8(+ T cells, and their ICAM-1 expression were clearly attenuated in the brain of resistant mice. An essential contribution of LIGHT, another LTbetaR ligand, could be excluded, as LIGHT deficient mice rapidly succumbed to ECM. CONCLUSIONS/SIGNIFICANCE: LTbetaR expressed on radioresistant resident stromal, probably endothelial cells, rather than hematopoietic cells, are essential for the development of ECM, as assessed by hematopoietic reconstitution experiment. Therefore, the data suggest that both functional LTbetaR and TNFR2 signaling are required and non-redundant for the development of microvascular pathology resulting in fatal ECM.

  20. The Deubiquitinating Enzyme Cylindromatosis Dampens CD8+ T Cell Responses and Is a Critical Factor for Experimental Cerebral Malaria and Blood–Brain Barrier Damage (United States)

    Schmid, Ursula; Stenzel, Werner; Koschel, Josephin; Raptaki, Maria; Wang, Xu; Naumann, Michael; Matuschewski, Kai; Schlüter, Dirk; Nishanth, Gopala


    Cerebral malaria is a severe complication of human malaria and may lead to death of Plasmodium falciparum-infected individuals. Cerebral malaria is associated with sequestration of parasitized red blood cells within the cerebral microvasculature resulting in damage of the blood–brain barrier and brain pathology. Although CD8+ T cells have been implicated in the development of murine experimental cerebral malaria (ECM), several other studies have shown that CD8+ T cells confer protection against blood-stage infections. Since the role of host deubiquitinating enzymes (DUBs) in malaria is yet unknown, we investigated how the DUB cylindromatosis (CYLD), an important inhibitor of several cellular signaling pathways, influences the outcome of ECM. Upon infection with Plasmodium berghei ANKA (PbA) sporozoites or PbA-infected red blood cells, at least 90% of Cyld−/− mice survived the infection, whereas all congenic C57BL/6 mice displayed signatures of ECM, impaired parasite control, and disruption of the blood–brain barrier integrity. Cyld deficiency prevented brain pathology, including hemorrhagic lesions, enhanced activation of astrocytes and microglia, infiltration of CD8+ T cells, and apoptosis of endothelial cells. Furthermore, PbA-specific CD8+ T cell responses were augmented in the blood of Cyld−/− mice with increased production of interferon-γ and granzyme B and elevated activation of protein kinase C-θ and nuclear factor “kappa light-chain enhancer” of activated B cells. Importantly, accumulation of CD8+ T cells in the brain of Cyld−/− mice was significantly reduced compared to C57BL/6 mice. Bone marrow chimera experiments showed that the absence of ECM signatures in infected Cyld−/− mice could be attributed to hematopoietic and radioresistant parenchymal cells, most likely endothelial cells that did not undergo apoptosis. Together, we were able to show that host deubiqutinating enzymes play an important role in ECM and that CYLD promotes

  1. Control of Disease Tolerance to Malaria by Nitric Oxide and Carbon Monoxide

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    Viktória Jeney


    Full Text Available Nitric oxide (NO and carbon monoxide (CO are gasotransmitters that suppress the development of severe forms of malaria associated with Plasmodium infection. Here, we addressed the mechanism underlying their protective effect against experimental cerebral malaria (ECM, a severe form of malaria that develops in Plasmodium-infected mice, which resembles, in many aspects, human cerebral malaria (CM. NO suppresses the pathogenesis of ECM via a mechanism involving (1 the transcription factor nuclear factor erythroid 2-related factor 2 (NRF-2, (2 induction of heme oxygenase-1 (HO-1, and (3 CO production via heme catabolism by HO-1. The protection afforded by NO is associated with inhibition of CD4+ T helper (TH and CD8+ cytotoxic (TC T cell activation in response to Plasmodium infection via a mechanism involving HO-1 and CO. The protective effect of NO and CO is not associated with modulation of host pathogen load, suggesting that these gasotransmitters establish a crosstalk-conferring disease tolerance to Plasmodium infection.

  2. Modelos animales para la malaria cerebral y su aplicabilidad para la investigación de nuevos fármacos

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    Bárbara Judith Mendiola


    Full Text Available La malaria cerebral es una de las complicaciones más importantes de la infección con Plasmodium falciparum. El 40% de la población mundial vive en áreas afectadas por la malaria, lo que ha resultado en aproximadamente 243 millones de casos clínicos y 863000 muertes en el 2008, la mayoría en niños menores de 5 años del África subsahariana. La malaria cerebral presenta un gran desafío en el esclarecimiento de su fisiopatología. Aunque no existe un modelo experimental que reproduzca todos los aspectos de la enfermedad en humanos, los modelos murinos han sido el instrumento más provechoso, entre ellos la infección de hospederos susceptibles con la cepa ANKA de Plasmodium berghei es el más generalizado. Los estudios de patogenia de la malaria cerebral experimental están fundamentados por más de 20 años de investigación. Este trabajo revisa los hallazgos recientes y selecciona los elementos cardinales que sustentan la relevancia y operatividad de estos modelos. Concluye que la caracterización conductual precisa y la descripción de los cambios histológicos, metabólicos e inmunológicos concomitantes en los modelos actuales pueden ser herramientas útiles para investigar las dianas y la efectividad de futuras intervenciones terapéuticas.

  3. The Effect of Annona Muricata Leaves Towards Blood Levels of Cxcl9 and Lymphoblast (Study in Cerebral Malaria Phase of Swiss Mice

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    Mohamed M.Y. Gadalla


    Full Text Available Cerebral malaria (CM forms part of the spectrum of severe malaria, with a case fatality rate ranging from 15% in adults in southeast Asia to 8.5% in children in Africa. A.Muricata was used to cure Malaria in traditional medicine. The research will examine the effect of it in the chemokine (C-X-C motif receptor 3 (CXCR3 binding chemokines, including chemokine (C-X-C motif ligand 4 (CXCL4, CXCL9. The intervented mice group were infected then the it’s spleen were cultured , incubation 72 hours and then analyzed the result. The CXCL9 level of PbA-infected mice treated with A. muricata are lower than group of infected mice without treatment. Lymphoblast level of PbA-infected mice treated with A. Muricata are higher than group of infected mice without treatment. A. Muricata treatment cure in the CM in the mice and may be a potential treatment in human CM.Cerebral malaria (CM adalah keadaan infeksi malaria yang berat dengan tingkat kefatalan dari 15% di Asia tenggara dan 8% di Afrika. A. Muricata secara tradisional dipakai mengobati CM. Riset ini meneliti pengaruh A. Muricata pada ikatan chemokine (C-X-C motif reseptor 3 (CXCR3termasuk chemokine (C-X-C motif ligand 4 (CXCL4 dan CXCL9. Kelompok mice intervensi diinfeksi dan limfanya di culture dalam inkubator 72 jam untuk dianalisis. Kadar PbA CXCL9 pada mencit intervensi yang diberi A. Muricata lebih rendah dari pada kontrol. Kadar PbA limfoblast intervensi lebihtinggi dari pada kontrol. A. Muricata memperbaiki CM pada mencit dan berpotensi sebagai pengobat pada CM manusia.

  4. IgE- and IgG mediated severe anaphylactic platelet transfusion reaction in a known case of cerebral malaria

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    B Shanthi


    Full Text Available Background: Allergic reactions occur commonly in transfusion practice. However, severe anaphylactic reactions are rare; anti-IgA (IgA: Immunoglobulin A in IgA-deficient patients is one of the well-illustrated and reported causes for such reactions. However, IgE-mediated hypersensitivity reaction through blood component transfusion may be caused in parasitic hyperimmunization for IgG and IgE antibodies. Case Report: We have evaluated here a severe anaphylactic transfusion reaction retrospectively in an 18year-old male, a known case of cerebral malaria, developed after platelet transfusions. The examination and investigations revealed classical signs and symptoms of anaphylaxis along with a significant rise in the serum IgE antibody level and IgG by hemagglutination method. Initial mild allergic reaction was followed by severe anaphylactic reaction after the second transfusion of platelets. Conclusion: Based on these results, screening of patients and donors with mild allergic reactions to IgE antibodies may help in understanding the pathogenesis as well as in planning for preventive desensitization and measures for safe transfusion.

  5. Platelets alter gene expression profile in human brain endothelial cells in an in vitro model of cerebral malaria.

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    Mathieu Barbier

    Full Text Available Platelet adhesion to the brain microvasculature has been associated with cerebral malaria (CM in humans, suggesting that platelets play a role in the pathogenesis of this syndrome. In vitro co-cultures have shown that platelets can act as a bridge between Plasmodium falciparum-infected red blood cells (pRBC and human brain microvascular endothelial cells (HBEC and potentiate HBEC apoptosis. Using cDNA microarray technology, we analyzed transcriptional changes of HBEC in response to platelets in the presence or the absence of tumor necrosis factor (TNF and pRBC, which have been reported to alter gene expression in endothelial cells. Using a rigorous statistical approach with multiple test corrections, we showed a significant effect of platelets on gene expression in HBEC. We also detected a strong effect of TNF, whereas there was no transcriptional change induced specifically by pRBC. Nevertheless, a global ANOVA and a two-way ANOVA suggested that pRBC acted in interaction with platelets and TNF to alter gene expression in HBEC. The expression of selected genes was validated by RT-qPCR. The analysis of gene functional annotation indicated that platelets induce the expression of genes involved in inflammation and apoptosis, such as genes involved in chemokine-, TREM1-, cytokine-, IL10-, TGFβ-, death-receptor-, and apoptosis-signaling. Overall, our results support the hypothesis that platelets play a pathogenic role in CM.

  6. The antimicrobial molecule trappin-2/elafin has anti-parasitic properties and is protective in vivo in a murine model of cerebral malaria (United States)

    Roussilhon, Christian; Bang, Gilles; Bastaert, Fabien; Solhonne, Brigitte; Garcia-Verdugo, Ignacio; Peronet, Roger; Druilhe, Pierre; Sakuntabhai, Anavaj; Mecheri, Salaheddine; Sallenave, Jean-Michel


    According to the WHO, and despite reduction in mortality rates, there were an estimated 438 000 malaria deaths in 2015. Therefore new antimalarials capable of limiting organ damage are still required. We show that systemic and lung adenovirus (Ad)-mediated over-expression of trappin-2 (T-2) an antibacterial molecule with anti-inflammatory activity, increased mice survival following infection with the cerebral malaria-inducing Plasmodium berghei ANKA (PbANKA) strain. Systemically, T-2 reduced PbANKA sequestration in spleen, lung, liver and brain, associated with a decrease in pro-inflammatory cytokines (eg TNF-α in spleen and lung) and an increase in IL-10 production in the lung. Similarly, local lung instillation of Ad-T-2 resulted in a reduced organ parasite sequestration and a shift towards an anti-inflammatory/repair response, potentially implicating monocytes in the protective phenotype. Relatedly, we demonstrated in vitro that human monocytes incubated with Plasmodium falciparum-infected red blood cells (Pf-iRBCs) and IgGs from hyper-immune African human sera produced T-2 and that the latter colocalized with merozoites and inhibited Pf multiplication. This array of data argues for the first time for the potential therapeutic usefulness of this host defense peptide in human malaria patients, with the aim to limit acute lung injury and respiratory distress syndrom often observed during malaria episodes. PMID:28181563

  7. Study on the association between environmental cadmium exposure, cytochrome P450-mediated 20-HETE, heme-oxygenase-1 polymorphism and hypertension in Thai population residing in a malaria endemic areas with cadmium pollution. (United States)

    Boonprasert, Kanyarat; Ruengweerayut, Ronnatrai; Satarug, Soisungwan; Na-Bangchang, Kesara


    The aims of the study were to investigate (i) the effects of environmental cadmium (Cd) on hypertension, biological markers of renal dysfunction and renal cytochrome P450-mediated arachidonate metabolism; and (ii) the association between genetic polymorphism of heme oxygenase-1 (HO-1) and hypertension and Cd-induced renal injury in the exposed Thai population. The study was conducted in adult subjects residing in Cd-contaminated malaria endemic areas of Mae Sot District, Thailand. All subjects were randomly selected and consistently distributed for sex, age and residential areas. Blood and urinary Cd levels were not significantly different between the case (hypertensive) and control (matched-pair normotensive) groups. While other renal dysfunction biomarkers were comparable between the two groups, urinary microalbumin, urinary 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) and serum creatinine were siginificantly higher in the hypertensive group. Only N-acetyl-β-glucosaminidase (NAG) showed positive correlation with Cd in hypertensive and normotensive group. With respect to heme oxygenase-1 (HO-1) polymorphism, the frequencies of (GT)(n) alleles were similar in both case and control groups. The frequency of SL genotype was significantly higher in the control group, whereas the frequency of ML genotype was significantly higher in the case group. Although no significant difference between 20-HETE and NAG levels in various HO-1 genotypes was found, a trend of increase in 20-HETE and NAG levels was observed in subjects carrying longer (GT)(n) repeats. Results from the present study provide no clear evidence on the direct effects of environmental Cd on high blood pressure development in the non-occupational exposed Thai population. Furthermore, the indirect effect of Cd through HO-1 (genetic polymorphism and prevalence of long GT(n) repeats) and 20-HETE was inconclusive. Based on the data obtained in the present investigation further studies should be performed

  8. Simultaneous host and parasite expression profiling identifies tissue-specific transcriptional programs associated with susceptibility or resistance to experimental cerebral malaria

    Directory of Open Access Journals (Sweden)

    Liles W Conrad


    Full Text Available Abstract Background The development and outcome of cerebral malaria (CM reflects a complex interplay between parasite-expressed virulence factors and host response to infection. The murine CM model, Plasmodium berghei ANKA (PbA, which simulates many of the features of human CM, provides an excellent system to study this host/parasite interface. We designed "combination" microarrays that concurrently detect genome-wide transcripts of both PbA and mouse, and examined parasite and host transcriptional programs during infection of CM-susceptible (C57BL/6 and CM-resistant (BALB/c mice. Results Analysis of expression data from brain, lung, liver, and spleen of PbA infected mice showed that both host and parasite gene expression can be examined using a single microarray, and parasite transcripts can be detected within whole organs at a time when peripheral blood parasitemia is low. Parasites display a unique transcriptional signature in each tissue, and lung appears to be a large reservoir for metabolically active parasites. In comparisons of susceptible versus resistant animals, both host and parasite display distinct, organ-specific transcriptional profiles. Differentially expressed mouse genes were related to humoral immune response, complement activation, or cell-cell interactions. PbA displayed differential expression of genes related to biosynthetic activities. Conclusion These data show that host and parasite gene expression profiles can be simultaneously analysed using a single "combination" microarray, and that both the mouse and malaria parasite display distinct tissue- and strain-specific responses during infection. This technology facilitates the dissection of host-pathogen interactions in experimental cerebral malaria and could be extended to other disease models.

  9. Schistosoma co-infection protects against brain pathology but does not prevent severe disease and death in a murine model of cerebral malaria. (United States)

    Bucher, Kirsten; Dietz, Klaus; Lackner, Peter; Pasche, Bastian; Fendel, Rolf; Mordmüller, Benjamin; Ben-Smith, Anne; Hoffmann, Wolfgang H


    Co-infections of helminths and malaria parasites are common in human populations in most endemic areas. It has been suggested that concomitant helminth infections inhibit the control of malaria parasitemia but down-modulate severe malarial disease. We tested this hypothesis using a murine co-infection model of schistosomiasis and cerebral malaria. C57BL/6 mice were infected with Schistosoma mansoni and 8-9 weeks later, when Schistosoma infection was patent, mice were co-infected with Plasmodium berghei ANKA strain. We found that a concomitant Schistosoma infection increased parasitemia at the beginning of the P. berghei infection. It did not protect against P. berghei-induced weight loss and hypothermia, and P. berghei-mono-infected as well as S. mansoni-P. berghei-co-infected animals showed a high case fatality between days 6 and 8 of malarial infection. However, co-infection significantly reduced P. berghei-induced brain pathology. Over 40% of the S. mansoni-P. berghei-co-infected animals that died during this period were completely protected against haemorrhaging, plugging of blood vessels and infiltration, indicating that mortality in these animals was not related to cerebral disease. Schistosoma mansoni-P. berghei-co-infected mice had elevated plasma concentrations of IL-5 and IL-13 and on day 6 lower levels of IFN-γ, IL-10, monocyte chemoattractant protein-1 (MCP-1) and monokine induced by IFN-γ (MIG) than P. berghei-mono-infected mice. We conclude that in P. berghei infections, disease and early death are caused by distinct pathogenic mechanisms, which develop in parallel and are differentially influenced by the immune response to S. mansoni. This might explain why, in co-infected mice, death could be induced in the absence of brain pathology.

  10. Identification of essential histidine residues involved in heme binding and Hemozoin formation in heme detoxification protein from Plasmodium falciparum. (United States)

    Nakatani, Keisuke; Ishikawa, Haruto; Aono, Shigetoshi; Mizutani, Yasuhisa


    Malaria parasites digest hemoglobin within a food vacuole to supply amino acids, releasing the toxic product heme. During the detoxification, toxic free heme is converted into an insoluble crystalline form called hemozoin (Hz). Heme detoxification protein (HDP) in Plasmodium falciparum is one of the most potent of the hemozoin-producing enzymes. However, the reaction mechanisms of HDP are poorly understood. We identified the active site residues in HDP using a combination of Hz formation assay and spectroscopic characterization of mutant proteins. Replacement of the critical histidine residues His122, His172, His175, and His197 resulted in a reduction in the Hz formation activity to approximately 50% of the wild-type protein. Spectroscopic characterization of histidine-substituted mutants revealed that His122 binds heme and that His172 and His175 form a part of another heme-binding site. Our results show that the histidine residues could be present in the individual active sites and could be ligated to each heme. The interaction between heme and the histidine residues would serve as a molecular tether, allowing the proper positioning of two hemes to enable heme dimer formation. The heme dimer would act as a seed for the crystal growth of Hz in P. falciparum.

  11. Systemic and cerebral vascular endothelial growth factor levels increase in murine cerebral malaria along with increased Calpain and caspase activity and can be reduced by erythropoietin treatment

    DEFF Research Database (Denmark)

    Hempel, Casper; Hoyer, Nils; Kildemoes, Anna


    increased levels of VEGF in brain and plasma and decreased plasma levels of soluble VEGF receptor 2. EPO treatment normalized VEGF receptor 2 levels and reduced brain VEGF levels. Hypoxia-inducible factor (HIF)-1α was significantly upregulated whereas cerebral HIF-2α and EPO levels remained unchanged....... Furthermore, we noticed increased caspase-3 and calpain activity in terminally ill mice, as measured by protease-specific cleavage of α-spectrin and p35. In conclusion, we detected increased cerebral and systemic VEGF as well as HIF-1α, which in the brain were reduced to normal in EPO-treated mice. Also...

  12. Lymphocyte Perturbations in Malawian Children with Severe and Uncomplicated Malaria. (United States)

    Mandala, Wilson L; Msefula, Chisomo L; Gondwe, Esther N; Gilchrist, James J; Graham, Stephen M; Pensulo, Paul; Mwimaniwa, Grace; Banda, Meraby; Taylor, Terrie E; Molyneux, Elizabeth E; Drayson, Mark T; Ward, Steven A; Molyneux, Malcolm E; MacLennan, Calman A


    Lymphocytes are implicated in immunity and pathogenesis of severe malaria. Since lymphocyte subsets vary with age, assessment of their contribution to different etiologies can be difficult. We immunophenotyped peripheral blood from Malawian children presenting with cerebral malaria, severe malarial anemia, and uncomplicated malaria (n = 113) and healthy aparasitemic children (n = 42) in Blantyre, Malawi, and investigated lymphocyte subset counts, activation, and memory status. Children with cerebral malaria were older than those with severe malarial anemia. We found panlymphopenia in children presenting with cerebral malaria (median lymphocyte count, 2,100/μl) and uncomplicated malaria (3,700/μl), which was corrected in convalescence and was absent in severe malarial anemia (5,950/μl). Median percentages of activated CD69(+) NK (73%) and γδ T (60%) cells were higher in cerebral malaria than in other malaria types. Median ratios of memory to naive CD4(+) lymphocytes were higher in cerebral malaria than in uncomplicated malaria and low in severe malarial anemia. The polarized lymphocyte subset profiles of different forms of severe malaria are independent of age. In conclusion, among Malawian children cerebral malaria is characterized by lymphocyte activation and increased memory cells, consistent with immune priming. In contrast, there are reduced memory cells and less activation in severe malaria anemia. Further studies are required to understand whether these immunological profiles indicate predisposition of some children to one or another form of severe malaria.

  13. Characterisation of the opposing effects of G6PD deficiency on cerebral malaria and severe malarial anaemia


    Mueller, Ivo; MalariaGEN Consortium


    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is believed to confer protection against Plasmodium falciparum malaria, but the precise nature of the protective effect has proved difficult to define as G6PD deficiency has multiple allelic variants with different effects in males and females, and it has heterogeneous effects on the clinical outcome of P. falciparum infection. Here we report an analysis of multiple allelic forms of G6PD deficiency in a large multi-centre case-control study ...

  14. CD4+ natural regulatory T cells prevent experimental cerebral malaria via CTLA-4 when expanded in vivo.

    Directory of Open Access Journals (Sweden)

    Ashraful Haque

    Full Text Available Studies in malaria patients indicate that higher frequencies of peripheral blood CD4(+ Foxp3(+ CD25(+ regulatory T (Treg cells correlate with increased blood parasitemia. This observation implies that Treg cells impair pathogen clearance and thus may be detrimental to the host during infection. In C57BL/6 mice infected with Plasmodium berghei ANKA, depletion of Foxp3(+ cells did not improve parasite control or disease outcome. In contrast, elevating frequencies of natural Treg cells in vivo using IL-2/anti-IL-2 complexes resulted in complete protection against severe disease. This protection was entirely dependent upon Foxp3(+ cells and resulted in lower parasite biomass, impaired antigen-specific CD4(+ T and CD8(+ T cell responses that would normally promote parasite tissue sequestration in this model, and reduced recruitment of conventional T cells to the brain. Furthermore, Foxp3(+ cell-mediated protection was dependent upon CTLA-4 but not IL-10. These data show that T cell-mediated parasite tissue sequestration can be reduced by regulatory T cells in a mouse model of malaria, thereby limiting malaria-induced immune pathology.

  15. Systemic and cerebral vascular endothelial growth factor levels increase in murine cerebral malaria along with increased Calpain and caspase activity and can be reduced by erythropoietin treatment

    DEFF Research Database (Denmark)

    Hempel, Casper; Hoyer, Nils; Kildemoes, Anna;


    . Furthermore, we noticed increased caspase-3 and calpain activity in terminally ill mice, as measured by protease-specific cleavage of α-spectrin and p35. In conclusion, we detected increased cerebral and systemic VEGF as well as HIF-1α, which in the brain were reduced to normal in EPO-treated mice. Also...... caspase and calpain activity was reduced markedly in EPO-treated mice....

  16. Malaria: toxins, cytokines and disease

    DEFF Research Database (Denmark)

    Jakobsen, P H; Bate, C A; Taverne, J;


    In this review the old concept of severe malaria as a toxic disease is re-examined in the light of recent discoveries in the field of cytokines. Animal studies suggest that the induction of TNF by parasite-derived molecules may be partly responsible for cerebral malaria and anemia, while hypoglyc...

  17. Malaria in Pregnancy

    Directory of Open Access Journals (Sweden)

    E E Okpere


    Full Text Available Malaria remains one of the highest contributors to the precarious maternal mortality figures in sub-Saharan Africa. At least 6 million women worldwide are at risk of malaria infection in pregnancy. Malaria contributes to at least 10, 000 maternal deaths and to at least 200, 000 newborn deaths annually. Malaria is a contributor or aetiologic factor in pregnancy complications including anaemia, spontaneous abortion, prematurity and stillbirths. Pregnancy results in increased incidence and severity of malaria. Cerebral malaria, acute renal failure and severe anaemia, rare complications in adults living in malaria endemic areas, may complicate malaria in pregnancy. Research implicate reduced maternal immunity from increased steroid levels in pregnancy, increased attractiveness of pregnant women to mosquito bites and increased adherence of parasitized erythrocytes to Chondroitin sulphate A expressed in the placentae. This is worse in the first and second pregnancies. With infection with the Human Immunodeficiency Virus [HIV], the effects of malaria in pregnancy are even worse. Over the decades, there have been concerted worldwide collaborative efforts, spearheaded by the World Health Organization [WHO] and including governments and allied agencies to tackle the scourge of malaria in pregnancy. The main thrusts of such efforts have been: to increase the use of insecticide treated mosquito bed nets [ITN]; intermittent preventive treatment of malaria [IPT]; and adequate case treatment of acute malaria attacks in pregnancy. While for IPT, Sulfadoxine-Pyrimethamine [SP] combination has been proven to be of benefit in preventing acute and latent malaria in pregnancy and its associated complications, the WHO has introduced the use of Artemisinin-Combination Therapy [ACT] for the first-line treatment of uncomplicated malaria in pregnancy, the need to confirm malaria before treatment and the enforcement of completion of therapy once started. The Roll Back

  18. Role of serum lactate and malarial retinopathy in prognosis and outcome of falciparum and vivax cerebral Malaria: A prospective cohort study in adult assamese tribes

    Directory of Open Access Journals (Sweden)

    Kaustubh Suresh Chaudhari


    Full Text Available Introduction: There is no comprehensive data or studies relating to clinical presentation and prognosis of cerebral malaria (CM in the tribal settlements of Assam. High rates of transmission and deaths from complicated malaria guided us to conduct a prospective observational cohort study to evaluate the factors associated with poor outcome and prognosis in patients of CM. Materials and Methods: We admitted 112 patients to the Bandarpara and Damodarpur Tribal Health Centers (THCs between 2011 and 2013 with a strict diagnosis of CM. We assessed the role of clinical, fundoscopy and laboratory findings (mainly lactic acid in the immediate outcome in terms of death and recovery, duration of hospitalization, neurocognitive impairment, cranial nerve palsies and focal neurological deficit. Results: The case fatality rate of CM was 33.03% and the prevalence of residual neurological sequelae at discharge was 16.07%. These are significantly higher than the previous studies. The mortality rate and neurological complications rate in patients with retinal whitening was 38.46% and 23.07%, with vessel changes was 25% and 18.75%, with retinal hemorrhage was 55.55% and 11.11% and with hyperlactatemia was 53.85% and 18.46%, respectively. Three patients of papilledema alone died. Conclusion: Our study suggests a strong correlation between hyperlactatemia, retinal changes (whitening, vessel changes and hemorrhage and depth and duration of coma with longer duration of hospitalization, increased mortality, neurological sequelae and death. Plasmodium vivax mono-infection as a cause of CM has been confirmed. Prognostic evaluation of CM is useful for judicious allocation of resources in the THC.

  19. Hemolysis-induced lethality involves inflammasome activation by heme. (United States)

    Dutra, Fabianno F; Alves, Letícia S; Rodrigues, Danielle; Fernandez, Patricia L; de Oliveira, Rosane B; Golenbock, Douglas T; Zamboni, Dario S; Bozza, Marcelo T


    The increase of extracellular heme is a hallmark of hemolysis or extensive cell damage. Heme has prooxidant, cytotoxic, and inflammatory effects, playing a central role in the pathogenesis of malaria, sepsis, and sickle cell disease. However, the mechanisms by which heme is sensed by innate immune cells contributing to these diseases are not fully characterized. We found that heme, but not porphyrins without iron, activated LPS-primed macrophages promoting the processing of IL-1β dependent on nucleotide-binding domain and leucine rich repeat containing family, pyrin domain containing 3 (NLRP3). The activation of NLRP3 by heme required spleen tyrosine kinase, NADPH oxidase-2, mitochondrial reactive oxygen species, and K(+) efflux, whereas it was independent of heme internalization, lysosomal damage, ATP release, the purinergic receptor P2X7, and cell death. Importantly, our results indicated the participation of macrophages, NLRP3 inflammasome components, and IL-1R in the lethality caused by sterile hemolysis. Thus, understanding the molecular pathways affected by heme in innate immune cells might prove useful to identify new therapeutic targets for diseases that have heme release.

  20. Altered regulation of Akt signaling with murine cerebral malaria, effects on long-term neuro-cognitive function, restoration with lithium treatment.

    Directory of Open Access Journals (Sweden)

    Minxian Dai

    Full Text Available Neurological and cognitive impairment persist in more than 20% of cerebral malaria (CM patients long after successful anti-parasitic treatment. We recently reported that long term memory and motor coordination deficits are also present in our experimental cerebral malaria model (ECM. We also documented, in a murine model, a lack of obvious pathology or inflammation after parasite elimination, suggesting that the long-term negative neurological outcomes result from potentially reversible biochemical and physiological changes in brains of ECM mice, subsequent to acute ischemic and inflammatory processes. Here, we demonstrate for the first time that acute ECM results in significantly reduced activation of protein kinase B (PKB or Akt leading to decreased Akt phosphorylation and inhibition of the glycogen kinase synthase (GSK3β in the brains of mice infected with Plasmodium berghei ANKA (PbA compared to uninfected controls and to mice infected with the non-neurotrophic P. berghei NK65 (PbN. Though Akt activation improved to control levels after chloroquine treatment in PbA-infected mice, the addition of lithium chloride, a compound which inhibits GSK3β activity and stimulates Akt activation, induced a modest, but significant activation of Akt in the brains of infected mice when compared to uninfected controls treated with chloroquine with and without lithium. In addition, lithium significantly reversed the long-term spatial and visual memory impairment as well as the motor coordination deficits which persisted after successful anti-parasitic treatment. GSK3β inhibition was significantly increased after chloroquine treatment, both in lithium and non-lithium treated PbA-infected mice. These data indicate that acute ECM is associated with abnormalities in cell survival pathways that result in neuronal damage. Regulation of Akt/GSK3β with lithium reduces neuronal degeneration and may have neuroprotective effects in ECM. Aberrant regulation of Akt

  1. A novel carbon monoxide-releasing molecule fully protects mice from severe malaria. (United States)

    Pena, Ana C; Penacho, Nuno; Mancio-Silva, Liliana; Neres, Rita; Seixas, João D; Fernandes, Afonso C; Romão, Carlos C; Mota, Maria M; Bernardes, Gonçalo J L; Pamplona, Ana


    Severe forms of malaria infection, such as cerebral malaria (CM) and acute lung injury (ALI), are mainly caused by the apicomplexan parasite Plasmodium falciparum. Primary therapy with quinine or artemisinin derivatives is generally effective in controlling P. falciparum parasitemia, but mortality from CM and other forms of severe malaria remains unacceptably high. Herein, we report the design and synthesis of a novel carbon monoxide-releasing molecule (CO-RM; ALF492) that fully protects mice against experimental CM (ECM) and ALI. ALF492 enables controlled CO delivery in vivo without affecting oxygen transport by hemoglobin, the major limitation in CO inhalation therapy. The protective effect is CO dependent and induces the expression of heme oxygenase-1, which contributes to the observed protection. Importantly, when used in combination with the antimalarial drug artesunate, ALF492 is an effective adjunctive and adjuvant treatment for ECM, conferring protection after the onset of severe disease. This study paves the way for the potential use of CO-RMs, such as ALF492, as adjunctive/adjuvant treatment in severe forms of malaria infection.

  2. Tempol, an intracellular antioxidant, inhibits tissue factor expression, attenuates dendritic cell function, and is partially protective in a murine model of cerebral malaria.

    Directory of Open Access Journals (Sweden)

    Ivo M B Francischetti

    Full Text Available BACKGROUND: The role of intracellular radical oxygen species (ROS in pathogenesis of cerebral malaria (CM remains incompletely understood. METHODS AND FINDINGS: We undertook testing Tempol--a superoxide dismutase (SOD mimetic and pleiotropic intracellular antioxidant--in cells relevant to malaria pathogenesis in the context of coagulation and inflammation. Tempol was also tested in a murine model of CM induced by Plasmodium berghei Anka infection. Tempol was found to prevent transcription and functional expression of procoagulant tissue factor in endothelial cells (ECs stimulated by lipopolysaccharide (LPS. This effect was accompanied by inhibition of IL-6, IL-8, and monocyte chemoattractant protein (MCP-1 production. Tempol also attenuated platelet aggregation and human promyelocytic leukemia HL60 cells oxidative burst. In dendritic cells, Tempol inhibited LPS-induced production of TNF-α, IL-6, and IL-12p70, downregulated expression of co-stimulatory molecules, and prevented antigen-dependent lymphocyte proliferation. Notably, Tempol (20 mg/kg partially increased the survival of mice with CM. Mechanistically, treated mice had lowered plasma levels of MCP-1, suggesting that Tempol downmodulates EC function and vascular inflammation. Tempol also diminished blood brain barrier permeability associated with CM when started at day 4 post infection but not at day 1, suggesting that ROS production is tightly regulated. Other antioxidants-such as α-phenyl N-tertiary-butyl nitrone (PBN; a spin trap, MnTe-2-PyP and MnTBAP (Mn-phorphyrin, Mitoquinone (MitoQ and Mitotempo (mitochondrial antioxidants, M30 (an iron chelator, and epigallocatechin gallate (EGCG; polyphenol from green tea did not improve survival. By contrast, these compounds (except PBN inhibited Plasmodium falciparum growth in culture with different IC50s. Knockout mice for SOD1 or phagocyte nicotinamide adenine dinucleotide phosphate (NADPH oxidase (gp91(phox-/- or mice treated with

  3. Measurement of heme concentration. (United States)

    Sinclair, P R; Gorman, N; Jacobs, J M


    Heme (iron protoporphyrin IX) is a prosthetic group for a number of hemoproteins in different tissues (e.g., hemoglobin, myoglobin, cytochrome P-450s, mitochondrial cytochromes, catalases, and peroxidases). Mutations in the biosynthetic pathway can affect the synthesis and/or degradation of heme. Several assays are provided in this unit for quantifying heme: a spectrophotometric assay based on the characteristic absorption spectrum of oxidized and reduced form of the hemochrome formed by replacing the nitrogen ligands with pyridine; a fluorescence assay based on removal of the iron by a heated, strong oxalic acid solution to produce fluorescent protoporphyrin; a reversed-phase HPLC assay to measure heme and intermediates in the synthetic pathway; and a radiometric assay to measure newly synthesized heme in tissue culture cells.

  4. The role of vitamin D in malaria. (United States)

    Lương, Khanh Vinh Quốc; Nguyễn, Lan Thi Hoàng


    An abnormal calcium-parathyroid hormone (PTH)-vitamin D axis has been reported in patients with malaria infection. A role for vitamin D in malaria has been suggested by many studies. Genetic studies have identified numerous factors that link vitamin D to malaria, including human leukocyte antigen genes, toll-like receptors, heme oxygenase-1, angiopoietin-2, cytotoxic T lymphocyte antigen-4, nucleotide-binding oligomerization domain-like receptors, and Bcl-2. Vitamin D has also been implicated in malaria via its effects on the Bacillus Calmette-Guerin (BCG) vaccine, matrix metalloproteinases, mitogen-activated protein kinase pathways, prostaglandins, reactive oxidative species, and nitric oxide synthase. Vitamin D may be important in malaria; therefore, additional research on its role in malaria is needed.

  5. Processing of heme and heme-containing proteins by bacteria. (United States)

    Stojiljkovic, Igor; Perkins-Balding, Donna


    An extensive amount of new knowledge on bacterial systems involved in heme processing has been accumulated in the last 10 years. We discuss common themes in heme transport across bacterial outer and inner membranes, emphasizing proteins and mechanisms involved. The processing of heme in the bacterial cytoplasm is extensively covered, and a new hypothesis about the fate of heme in the bacterial cell is presented. Auxiliary genes involved in heme utilization, i.e., TonB, proteases, proteins involved in heme storage and pigmentation, as well as genes involved in regulation of heme assimilation are reviewed.

  6. Malaria in pregnancy. (United States)

    Seal, Subrata Lall; Mukhopadhay, Sima; Ganguly, Rajendra Prasad


    Malaria during pregnancy is a recognised risk factor for maternal and foetal complications and it is endemic in certain areas of our country. Pregnancy also enhances the severity of malaria particularly with P falciparum infestation. The outcome of effects of malaria in pregnancy on the mother and foetus is studied here. This is a prospective observational study conducted in the department of obstetrics and gynaecology of RG Kar Medical College during the period from 1st January 2001 to 31st December 2006. Forty pregnant women with malaria in pregnancy were studied. Another 40 non- pregnant women during the same period were served as control. The maternal complications were compared with the controls and the outcome of pregnancy was studied. There was statistically significant (p renal failure, hepatic failure, hypoglycaemia, hypotension and death in the pregnant women in comparison to non-pregnant women. P falciparum infection was also more during pregnancy. There was also increased incidence of abqrtion, preterm labour, intra-uterine growth restriction and intra-uterine foetal death. Treatment with antimalarial drugs particularly in cerebral malaria does not give good results as there were 12 maternal deaths in this series. Every attempt should be made to prevent malaria during pregnancy by various measures as it is associated with high maternal morbidity and mortality and adversely affects the neonatal outcome.

  7. Disseminated intravascular coagulation in malaria: A case report

    Directory of Open Access Journals (Sweden)

    Laltanpuii Sailo


    Full Text Available Disseminated intravascular coagulation (DIC is seen in <5% of patients with severe Plasmodium falciparum malaria and is more common in cerebral malaria. Here, we report the diagnosis and management of a case of severe P. falciparum malaria with DIC.

  8. High-Throughput Testing of Antibody-Dependent Binding Inhibition of Placental Malaria Parasites

    DEFF Research Database (Denmark)

    Nielsen, Morten A; Salanti, Ali


    The particular virulence of Plasmodium falciparum manifests in diverse severe malaria syndromes as cerebral malaria, severe anemia and placental malaria. The cause of both the severity and the diversity of infection outcome, is the ability of the infected erythrocyte (IE) to bind a range......-throughput assay used in the preclinical and clinical development of a VAR2CSA based vaccine against placental malaria....

  9. Plasmodium vivax hospitalizations in a monoendemic malaria region: severe vivax malaria? (United States)

    Quispe, Antonio M; Pozo, Edwar; Guerrero, Edith; Durand, Salomón; Baldeviano, G Christian; Edgel, Kimberly A; Graf, Paul C F; Lescano, Andres G


    Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical features, we performed a retrospective case control study in the subregion of Luciano Castillo Colonna, Piura, Peru, an area with nearly exclusive vivax malaria transmission. Severe cases and the subset of critically ill cases were compared with a random set of uncomplicated malaria cases (1:4). Between 2008 and 2009, 6,502 malaria cases were reported, including 106 hospitalized cases, 81 of which fit the World Health Organization definition for severe malaria. Of these 81 individuals, 28 individuals were critically ill (0.4%, 95% confidence interval = 0.2-0.6%) with severe anemia (57%), shock (25%), lung injury (21%), acute renal failure (14%), or cerebral malaria (11%). Two potentially malaria-related deaths occurred. Compared with uncomplicated cases, individuals critically ill were older (38 versus 26 years old, P malaria monoinfection with critical illness is more common than previously thought.

  10. Dioxygen reactivity of meso-hydroxylated hemes: intermediates in heme degradation process catalyzed by heme oxygenase

    Indian Academy of Sciences (India)

    Sankar Prasad Rath


    Heme oxygenase (HO) is the only enzyme in mammals known to catalyse the physiological degradation of unwanted heme into biliverdin, Fe ion and CO. The process involves introduction of the hydroxyl group at one of its meso-positions as the first fundamental step of the heme cleavage process. It was also found that meso-amino heme undergoes similar ring-cleavage process while reacting with dioxygen in presence of pyridine as an axial ligand. The present paper briefly reviews the reactions of model meso-hydroxylated heme and its analogues with dioxygen, and their relevance in the heme degradation process.

  11. How Heme Oxygenase-1 Prevents Heme-Induced Cell Death.

    Directory of Open Access Journals (Sweden)

    Lilibeth Lanceta

    Full Text Available Earlier observations indicate that free heme is selectively toxic to cells lacking heme oxygenase-1 (HO-1 but how this enzyme prevents heme toxicity remains unexplained. Here, using A549 (human lung cancer and immortalized human bronchial epithelial cells incubated with exogenous heme, we find knock-down of HO-1 using siRNA does promote the accumulation of cell-associated heme and heme-induced cell death. However, it appears that the toxic effects of heme are exerted by "loose" (probably intralysosomal iron because cytotoxic effects of heme are lessened by pre-incubation of HO-1 deficient cells with desferrioxamine (which localizes preferentially in the lysosomal compartment. Desferrioxamine also decreases lysosomal rupture promoted by intracellularly generated hydrogen peroxide. Supporting the importance of endogenous oxidant production, both chemical and siRNA inhibition of catalase activity predisposes HO-1 deficient cells to heme-mediated killing. Importantly, it appears that HO-1 deficiency somehow blocks the induction of ferritin; control cells exposed to heme show ~10-fold increases in ferritin heavy chain expression whereas in heme-exposed HO-1 deficient cells ferritin expression is unchanged. Finally, overexpression of ferritin H chain in HO-1 deficient cells completely prevents heme-induced cytotoxicity. Although two other products of HO-1 activity--CO and bilirubin--have been invoked to explain HO-1-mediated cytoprotection, we conclude that, at least in this experimental system, HO-1 activity triggers the induction of ferritin and the latter is actually responsible for the cytoprotective effects of HO-1 activity.

  12. Malaria (For Parents) (United States)

    ... Old Feeding Your 1- to 2-Year-Old Malaria KidsHealth > For Parents > Malaria A A A What's ... Prevention Diagnosis and Treatment en español Malaria About Malaria Malaria is a common infection in hot, tropical ...

  13. The heme oxygenase system and its functions in the brain. (United States)

    Maines, M D


    The heme oxygenase (HO) system was identified in the early 1970s as a distinct microsomal enzyme system that catalyzes formation of bile pigments (Maines and Kappas, 1974). Up to the early 1990s the system was considered only as a "molecular wrecking ball" (Lane, 1998) for degradation of the heme molecule and production of toxic waste products, CO and bile pigments. For those years, the HO system remained relatively unknown to the research community. In a rather short span of the past 10 years following the discovery of high levels of a second form of the enzyme, HO-2, in the brain, suggesting that "heme oxygenase in the brain has functions aside from heme degradation" (Sun et al., 1990); concomitant with finding that another toxic gas, NO, is a signal molecule for generation of cGMP (Ignarro et al., 1982), the system was propelled into main stream research. This propulsion was fueled by the realization of the multiple and diverse functions of heme degradation products. Heme oxygenase has now found relevance in all kinds of human pathophysiology ranging from stroke, cancer, multiple sclerosis, and malaria to transplantation and immune response. As it turns out, its potential benefits are mesmerizing investigators in diverse fields (Lane, 1998). The most recent findings with HO-2 being a hemoprotein and potentially an intracellular "sink" for NO (McCoubrey et al., 1997a; Ding et al., 1999), together with the discovery of the third form of the enzyme, HO-3 (McCoubrey et al., 1997b), are likely to insure the widespread interest in the enzyme system in the coming years. The present review is intended to highlight molecular properties of HO isozymes and their likely functions in the brain. Extended reviews of the system are found in Maines (1992, 1997).

  14. Recrudescence of Plasmodium falciparum malaria contracted in Lombok, Indonesia after quinine/doxycycline and mefloquine: case report. (United States)

    Tish, K N; Pillans, P I


    A patient is reported who contracted Plasmodium falciparum malaria in Lombok, Indonesia. The infection recrudesced after quinine/doxycycline and mefloquine. Treatment with halofantrine was successful after he developed cerebral malaria with recovery.

  15. Clinical pattern of severe Plasmodium falciparum malaria in Sudan in an area characterized by seasonal and unstable malaria transmission

    DEFF Research Database (Denmark)

    Giha, H A; Elghazali, G; A-Elgadir, T M E


    malarial anemia (45.4%), followed by convulsions (21%), cerebral malaria (16. 4%) and hypotension (11.8%). Severe malaria was recognized in all age groups, but 44.5% of patients were aged 2 to 4 years. The mean ages of patients with severe anemia (5.6 years) and convulsions (5.9 years) were significantly...... lower than the mean ages of patients with cerebral malaria (14.1 years) or hypotension (35.2 years). Patients with convulsions and cerebral malaria had significantly higher mean parasite count (69972 and 56110 parasites/microL, respectively) than patients with severe anemia (24637 parasites...

  16. [Malaria websites]. (United States)

    Genton, B


    One click on, key-word "Malaria", 24,900,000 entries. How to choose among this jungle of websites? Ten sites are proposed to meet the needs of the general practitioner They are categorized by focus of interest, namely 1) detailed information on pre- and post-travel advice and management of travelers with illness upon return, 2) the essential on the parasite, the diagnosis and the treatment, 3) the malaria problem worldwide and 4) malaria maps.

  17. Therapeutic Approaches to Limit Hemolysis-Driven Endothelial Dysfunction: Scavenging Free Heme to Preserve Vasculature Homeostasis

    Directory of Open Access Journals (Sweden)

    Francesca Vinchi


    Full Text Available Hemolysis results in the release of hemoglobin and heme into the bloodstream and is associated with the development of several pathologic conditions of different etiology, including hemoglobinopathies, hemolytic anemias, bacterial infections, malaria, and trauma. In addition, hemolysis is associated with surgical procedures, hemodialysis, blood transfusion, and other conditions in which mechanical forces can lead to red blood cell rupture. Free plasma hemoglobin and heme are toxic for the vascular endothelium since heme iron promotes oxidative stress that causes endothelial activation responsible for vasoocclusive events and thrombus formation. Moreover, free hemoglobin scavenges nitric oxide, reducing its bioavailability, and heme favours ROS production, thus causing oxidative nitric oxide consumption. This results in the dysregulation of the endothelium vasodilator:vasoconstrictor balance, leading to severe vasoconstriction and hypertension. Thus, endothelial dysfunction and impairment of cardiovascular function represent a common feature of pathologic conditions associated with hemolysis. In this review, we discuss how hemoglobin/heme released following hemolysis may affect vascular function and summarise the therapeutic approaches available to limit hemolysis-driven endothelial dysfunction. Particular emphasis is put on recent data showing the beneficial effects obtained through the use of the plasma heme scavenger hemopexin in counteracting heme-mediated endothelial damage in mouse models of hemolytic diseases.

  18. Iron, anemia and hepcidin in malaria

    Directory of Open Access Journals (Sweden)

    Natasha eSpottiswoode


    Full Text Available Malaria and iron have a complex but important relationship. Plasmodium proliferation requires iron, both during the clinically silent liver stage of growth and in the disease-associated phase of erythrocyte infection. Precisely how the protozoan acquires its iron from its mammalian host remains unclear, but iron chelators can inhibit pathogen growth in vitro and in animal models. In humans, iron deficiency appears to protect against severe malaria, while iron supplementation increases risks of infection and disease. Malaria itself causes profound disturbances in physiological iron distribution and utilization, through mechanisms that include hemolysis, release of heme, dyserythropoiesis, anemia, deposition of iron in macrophages, and inhibition of dietary iron absorption. These effects have significant consequences. Malarial anemia is a major global health problem, especially in children, that remains incompletely understood and is not straightforward to treat. Furthermore, the changes in iron metabolism during a malaria infection may modulate susceptibility to coinfections. The release of heme and accumulation of iron in granulocytes may explain increased vulnerability to non-typhoidal Salmonella during malaria. The redistribution of iron away from hepatocytes and into macrophages may confer host resistance to superinfection, whereby blood-stage parasitemia prevents the development of a second liver-stage Plasmodium infection in the same organism. Key to understanding the pathophysiology of iron metabolism in malaria is the activity of the iron regulatory hormone hepcidin. Hepcidin is upregulated during blood-stage parasitemia and likely mediates much of the iron redistribution that accompanies disease. Understanding the regulation and role of hepcidin may offer new opportunities to combat malaria and formulate better approaches to treat anemia in the developing world.

  19. The Legend of Sally Hemings (United States)

    Belz, Herman


    The part played by Sally Hemings in the life of Thomas Jefferson has been regarded as provocatively dubious since political enemy James Callender claimed in 1802 that Jefferson was the father of several of Hemings's children. Historian Merrill Peterson, observing that paternity is hard to prove, wrote in 1960 that no concrete evidence was ever…

  20. Malaria Matters

    Centers for Disease Control (CDC) Podcasts


    This podcast gives an overview of malaria, including prevention and treatment, and what CDC is doing to help control and prevent malaria globally.  Created: 4/18/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 4/18/2008.

  1. The heme-heme oxygenase system: a molecular switch in wound healing.

    NARCIS (Netherlands)

    Wagener, F.A.D.T.G.; Beurden, H.E. van; Hoff, J.W. Von den; Adema, G.J.; Figdor, C.G.


    When cells are injured they release their contents, resulting in a local accumulation of free heme proteins and heme. Here, we investigated the involvement of heme and its degrading enzyme heme oxygenase (HO) in the inflammatory process during wound healing. We observed that heme directly accumulate

  2. Malaria and Travelers (United States)

    ... a CDC Malaria Branch clinician. Malaria and Travelers Recommend on Facebook Tweet Share Compartir ... may be at risk for infection. Determine if malaria transmission occurs at the destinations Obtain a detailed ...

  3. Malaria Treatment (United States) (United States)

    ... a CDC Malaria Branch clinician. Malaria Treatment (United States) Recommend on Facebook Tweet Share Compartir Treatment of Malaria: Guidelines For Clinicians (United States) Download PDF version ...


    Directory of Open Access Journals (Sweden)

    Girish Pamappa


    Full Text Available Renal failure is a serious complication of malaria, with a mortality of 14 to 33%. In view of the significant morbidity and mortality due to acute renal failure in malaria, there is need to identify patients at an early stage and to intensify care given to reduce morbidity and mortality. AIMS  To evaluate the clinical profile of Acute Renal Failure (ARF in malaria.  To evaluate the factors associated with adverse outcome, relation of severity of renal impairment on final outcome in patients with ARF due to malaria. MATERIAL AND METHODS This study was conducted at a tertiary care hospital over a period of 12 months. STUDY DESIGN  Type of study: Prospective Analytical, Observational Study.  Sample Size: 50 patients admitted to ICU, Kidney Unit, and the Medicine Wards with Malaria and ARF. Inclusion Criteria Clinically screened patients with evidence of malarial parasites in the blood smears or by antigen detection with clinical features or biochemical evidence of acute renal failure. Exclusion Criteria  Presence of any disease or condition leading to ARF or affecting the outcome of malarial ARF.  Other causes of Fever, Jaundice and Oliguria, like Leptospirosis, Dengue. METHODOLOGY Fifty patients who fulfilled the inclusion criteria were interrogated with regards to the complaints, clinical signs. Blood tests were sent on admission. Details were recorded as per the clinical proforma. The patients were followed until their discharge/death. RESULTS Oliguria was present in only 30% of patients. 30% of patients received haemodialysis. The mortality was 12% for severe renal failure. On Univariate analysis, Acidosis and Cerebral malaria were highly significant predictors of mortality. Other significant predictors were Renal failure, Oliguria, Shock, DIC, Hyperparasitemia, Leukocytosis (TLC. On Multivariate analysis, Oliguria, Cerebral malaria, Acidosis, Shock and two or more complications were the independent predictors of mortality

  5. G-quadruplex DNAzymes-induced highly selective and sensitive colorimetric sensing of free heme in rat brain. (United States)

    Li, Ruimin; Jiang, Qin; Cheng, Hanjun; Zhang, Guoqiang; Zhen, Mingming; Chen, Daiqin; Ge, Jiechao; Mao, Lanqun; Wang, Chunru; Shu, Chunying


    Direct selective determination of free heme in the cerebral system is of great significance due to the crucial roles of free heme in physiological and pathological processes. In this work, a G-quadruplex DNAzymes-induced highly sensitive and selective colorimetric sensing of free heme in rat brain is established. Initially, the conformation of an 18-base G-rich DNA sequence, PS2.M (5'-GTGGGTAGGGCGGGTTGG-3'), in the presence of K(+), changes from a random coil to a "parallel" G-quadruplex structure, which can bind free heme in the cerebral system with high affinity through π-π stacking. The resulted heme/G-quadruplex complex exhibits high peroxidase-like activity, which can be used to catalyze the oxidation of colorless ABTS(2-) to green ABTS˙(-) by H2O2. The concentration of heme can be evaluated by the naked eye and determined by UV-vis spectroscopy. The signal output showed a linear relationship for heme within the concentration range from 1 to 120 nM with a detection limit of 0.637 nM. The assay demonstrated here was highly selective and free from the interference of physiologically important species such as dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbate acid (AA), cysteine, uric acid (UA), glucose and lactate in the cerebral system. The basal dialysate level of free heme in the microdialysate from the striatum of adult male Sprague-Dawley rats was determined to be 32.8 ± 19.5 nM (n = 3). The analytic protocol possesses many advantages, including theoretical simplicity, low-cost technical and instrumental demands, and responsible detection of heme in rat brain microdialysate.

  6. The P. aeruginosa Heme Binding Protein PhuS is a Heme Oxygenase Titratable Regulator of Heme Uptake



    The Pseudomonas aeruginosa heme utilization (Phu) system encodes several proteins involved in the acquisition of heme as an iron source. Once internalized heme is degraded by the iron-regulated heme oxygenase, HemO to biliverdin (BV) IXδ and β. In vitro studies have shown holo-PhuS transfers heme to the iron-regulated HemO. This protein-protein interaction is specific for HemO as PhuS does not interact with the α-regioselective heme oxygenase, BphO. Bacterial genetics and isotopic labeling...

  7. Structural Characterization of Heme Environmental Mutants of CgHmuT that Shuttles Heme Molecules to Heme Transporters

    Directory of Open Access Journals (Sweden)

    Norifumi Muraki


    Full Text Available Corynebacteria contain a heme uptake system encoded in hmuTUV genes, in which HmuT protein acts as a heme binding protein to transport heme to the cognate transporter HmuUV. The crystal structure of HmuT from Corynebacterium glutamicum (CgHmuT reveals that heme is accommodated in the central cleft with His141 and Tyr240 as the axial ligands and that Tyr240 forms a hydrogen bond with Arg242. In this work, the crystal structures of H141A, Y240A, and R242A mutants were determined to understand the role of these residues for the heme binding of CgHmuT. Overall and heme environmental structures of these mutants were similar to those of the wild type, suggesting that there is little conformational change in the heme-binding cleft during heme transport reaction with binding and the dissociation of heme. A loss of one axial ligand or the hydrogen bonding interaction with Tyr240 resulted in an increase in the redox potential of the heme for CgHmuT to be reduced by dithionite, though the wild type was not reduced under physiological conditions. These results suggest that the heme environmental structure stabilizes the ferric heme binding in CgHmuT, which will be responsible for efficient heme uptake under aerobic conditions where Corynebacteria grow.

  8. Studying Different Clinical Syndromes Of Paediatric Severe Malaria Using Plasma Proteomics

    KAUST Repository

    Ramaprasad, Abhinay


    Background- Severe Plasmodium falciparum malaria remains one of the major causes of childhood morbidity and mortality in Africa. Severe malaria manifests itself as three main clinical syndromes-impaired consciousness (cerebral malaria), respiratory distress and severe malarial anaemia. Cerebral malaria and respiratory distress are major contributors to malaria mortality but their pathophysiology remains unclear. Motivation/Objectives- Most children with severe malaria die within the first 24 hours of admission to a hospital because of their pathophysiological conditions. Thus, along with anti-malarial drugs, various adjuvant therapies such as fluid bolus (for hypovolaemia) and anticonvulsants (for seizures) are given to alleviate the sick child’s condition. But these therapies can sometimes have adverse effects. Hence, a clear understanding of severe malaria pathophysiology is essential for making an informed decision regarding adjuvant therapies. Methodology- We used mass spectrometry-based shotgun proteomics to study plasma samples from Gambian children with severe malaria. We compared the proteomic profiles of different severe malaria syndromes and generated hypotheses regarding the underlying disease mechanisms. Results/Conclusions- The main challenges of studying the severe malaria syndromes using proteomics were the high complexity and variability among the samples. We hypothesized that hepatic injury and nitric oxide play roles in the pathophysiology of cerebral malaria and respiratory distress.

  9. Non-heme iron as ferrous sulfate does not interact with heme iron absorption in humans. (United States)

    Gaitán, Diego; Olivares, Manuel; Lönnerdal, Bo; Brito, Alex; Pizarro, Fernando


    The absorption of heme iron has been described as distinctly different from that of non-heme iron. Moreover, whether heme and non-heme iron compete for absorption has not been well established. Our objective was to investigate the potential competition between heme and non-heme iron as ferrous sulfate for absorption, when both iron forms are ingested on an empty stomach. Twenty-six healthy nonpregnant women were selected to participate in two iron absorption studies using iron radioactive tracers. We obtained the dose-response curve for absorption of 0.5, 10, 20, and 50 mg heme iron doses, as concentrated red blood cells. Then, we evaluated the absorption of the same doses, but additionally we added non-heme iron, as ferrous sulfate, at constant heme/non-heme iron molar ratio (1:1). Finally, we compare the two curves by a two-way ANOVA. Iron sources were administered on an empty stomach. One factor analysis showed that heme iron absorption was diminished just by increasing total heme iron (P heme iron as ferrous sulfate did not have any effect on heme iron absorption (P = NS). We reported evidence that heme and non-heme iron as ferrous sulfate does not compete for absorption. The mechanism behind the absorption of these iron sources is not clear.

  10. Measurement of heme efflux and heme content in isolated developing chloroplasts. [Cucumis sativus, cv. Sumter

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J.; Weinstein, J.D. (Clemson Univ., SC (USA))


    Hemes destined for cytosolic hemoproteins must originate in one of the cellular compartments which have the capacity for heme synthesis, namely the chloroplast or the mitochondria. Since developing chloroplasts from greening cucumber (Cucumis sativus, cv. Sumter) cotyledons are known to contain complete heme and chlorophyll biosynthetic pathways, they were tested for their capacity export hemes. Picomole quantities of heme were measured by reconstitution of the heme with apo-peroxidase and subsequent determination of peroxidase activity. The assay method was sensitive (as little as 0.7 picomole of heme could be detected in a volume of 100 microliters) and was linear with heme concentration. When intact plastids were incubated with apo-peroxidase, a steady-state rate of efflux between 0.12 and 0.45 picomole heme/minute/milligram plastid protein was measured. The efflux rate was not due to plastid breakage and could be enhanced by incubating with the heme precursor, {delta}-aminolevulinic acid. Cold acetone extraction removed 47 {plus minus} 17 picomoles heme/milligram plastid protein from the total b-type heme pool in the chloroplasts (166 {plus minus} 9 picomoles heme/milligram protein, by acid-acetone extraction). The reconstitution technique provided a similar estimate of readily exchangeable heme in the plastid, 37 {plus minus} 8 picomoles heme/milligram protein (or 6 micromolar in the plastids). These values may be indicative of a free heme pool which exists in the chloroplast.

  11. The ¿/d T-cell response to Plasmodium falciparum malaria in a population in which malaria is endemic

    DEFF Research Database (Denmark)

    Hviid, L; Kurtzhals, J A; Dodoo, D


    Frequencies and absolute numbers of peripheral gamma/delta T cells have been reported to increase after episodes of Plasmodium falciparum malaria in adults with limited or no previous malaria exposure. In contrast, little is known about the gamma/delta T-cell response to malaria in children from...... areas where malaria is endemic, who bear the burden of malaria-related morbidity and mortality. We investigated the gamma/delta T-cell response in 19 Ghanaian children from an area of hyperendemic, seasonal malaria transmission. The children presented with cerebral malaria (n = 7), severe malarial...... anemia (n = 5), or uncomplicated malaria (n = 7) and were monitored from admission until 4 weeks later. We found no evidence of increased frequencies of gamma/delta T cells in any of the patient groups, whereas one adult expatriate studied in Ghana and three adults admitted to the hospital in Copenhagen...

  12. Heme degradation and human disease: diversity is the soul of life. (United States)

    Shibahara, Shigeki; Kitamuro, Tomomi; Takahashi, Kazuhiro


    We all depend on molecular oxygen and heme for our life, as evident from the pigments in blood and daily wastes. About 80% of serum bilirubin is derived from hemoglobin of senescent erythrocytes, which have finished their mission of 120 days and have been phagocytized by macrophages in the reticuloendothelial system. Here we present an overview of the heme degradation processes and relevant disorders by focusing on heme oxygenase-1 (HO-1), a key enzyme in heme catabolism. HO-1 cleaves the porphyrin macrocycle of heme at the expense of molecular oxygen to release a linear tetrapyrrole biliverdin, carbon monoxide, and ferrous iron; biliverdin is rapidly reduced to bilirubin. Bilirubin is transported to the liver (hepatocytes), conjugated with glucuronic acid by bilirubin UDP-glucuronosyltransferase, and excreted into bile. Genetic diversity, a strategy in the host defense, is seen in the human ho-1 and UDP-glucuronosyltransferase genes. Moreover, striking interspecies variations are noted in the regulation of HO-1 expression by hypoxia, heat shock, or interferon-gamma, each of which mainly represses HO-1 expression in human cells. Implications of such a variety are discussed in relevance to the pathogenesis of severe malaria caused by Plasmodium falciparum, the most ancient foe of humans.

  13. Kompliceret malaria

    DEFF Research Database (Denmark)

    Rønn, A M; Bygbjerg, Ib Christian; Jacobsen, E


    An increasing number of cases of malaria, imported to Denmark, are caused by Plasmodium falciparum and severe and complicated cases are more often seen. In the Department of Infectious Diseases, Rigshospitalet, 23 out of 32 cases, hospitalized from 1.1-30.6.1988, i.e. 72%, were caused by P...

  14. Malaria-related anaemia: a Latin American perspective

    Directory of Open Access Journals (Sweden)

    Juan Pablo Quintero


    Full Text Available Malaria is the most important parasitic disease worldwide, responsible for an estimated 225 million clinical cases each year. It mainly affects children, pregnant women and non-immune adults who frequently die victims of cerebral manifestations and anaemia. Although the contribution of the American continent to the global malaria burden is only around 1.2 million clinical cases annually, there are 170 million inhabitants living at risk of malaria transmission in this region. On the African continent, where Plasmodium falciparum is the most prevalent human malaria parasite, anaemia is responsible for about half of the malaria-related deaths. Conversely, in Latin America (LA, malaria-related anaemia appears to be uncommon, though there is a limited knowledge about its real prevalence. This may be partially explained by several factors, including that the overall malaria burden in LA is significantly lower than that of Africa, that Plasmodium vivax, the predominant Plasmodium species in the region, appears to display a different clinical spectrus and most likely because better health services in LA prevent the development of severe malaria cases. With the aim of contributing to the understanding of the real importance of malaria-related anaemia in LA, we discuss here a revision of the available literature on the subject and the usefulness of experimental animal models, including New World monkeys, particularly for the study of the mechanisms involved in the pathogenesis of malaria.

  15. Acute cerebellar ataxia: A neurological manifestation in malaria

    Directory of Open Access Journals (Sweden)

    Peddametla Shravan Kumar


    Full Text Available Malaria is a vector-borne disease transmitted by the bite of an infected female anopheles mosquito presents with varied clinical manifestations. Neurological manifestations include headaches, confusion, convulsions, hemiplegia, ataxia, cerebral palsy, cortical blindness, and Guillain-Barre syndrome (GBS. We are presenting a case report of acute cerebellar ataxia in a 20-year-old male patient who presented with fever and positive for Plasmodium vivax and Plasmodium falciparum malaria antibodies.

  16. Investigating the Pathogenesis of Severe Malaria: A Multidisciplinary and Cross-Geographical Approach


    Wassmer, Samuel C; Terrie E Taylor; Pradipsinh K Rathod; Mishra, Saroj K; Mohanty, Sanjib; Arevalo-Herrera, Myriam; Duraisingh, Manoj T; Joseph D. Smith


    More than a century after the discovery of Plasmodium spp. parasites, the pathogenesis of severe malaria is still not well understood. The majority of malaria cases are caused by Plasmodium falciparum and Plasmodium vivax, which differ in virulence, red blood cell tropism, cytoadhesion of infected erythrocytes, and dormant liver hypnozoite stages. Cerebral malaria coma is one of the most severe manifestations of P. falciparum infection. Insights into its complex pathophysiology are emerging t...

  17. The Impact of Genetic Susceptibility to Systemic Lupus Erythematosus on Placental Malaria in Mice



    Severe malaria, including cerebral malaria (CM) and placental malaria (PM), have been recognized to have many of the features of uncontrolled inflammation. We recently showed that in mice genetic susceptibility to the lethal inflammatory autoimmune disease, systemic lupus erythematosus (SLE), conferred resistance to CM. Protection appeared to be mediated by immune mechanisms that allowed SLE-prone mice, prior to the onset of overt SLE symptoms, to better control their inflammatory response to...

  18. Fatal complications of Plasmodium vivax malaria: A series of three case reports

    Directory of Open Access Journals (Sweden)

    Deepak Sundriyal


    Full Text Available Plasmodium vivax malaria once thought to be benign, is now being seen increasingly as complicated disease in various manifestations. These complications include cerebral malaria, acute respiratory distress syndrome, acute pancreatitis, hepatic dysfunction, coagulopathy-associated hemorrhages, and others. Even if at the onset, disease appears benign, clinicians should be careful to watch for the complications and timely management.

  19. Determinants of variant surface antigen antibody response in severe Plasmodium falciparum malaria in an area of low and unstable malaria transmission

    DEFF Research Database (Denmark)

    A-Elgadir, T M E; Theander, T G; Elghazali, G


    The variant surface antigens (VSA) of infected erythrocytes are important pathogenic markers, a set of variants (VSA(SM)), were assumed to be associated with severe malaria (SM), while SM constitutes clinically diverse forms, such as, severe malarial anemia (SMA) and cerebral malaria (CM). This s......The variant surface antigens (VSA) of infected erythrocytes are important pathogenic markers, a set of variants (VSA(SM)), were assumed to be associated with severe malaria (SM), while SM constitutes clinically diverse forms, such as, severe malarial anemia (SMA) and cerebral malaria (CM.......001). Parasites obtained from patients with SMA or from children were better recognized than isolates obtained from patients with uncomplicated malaria or from adults, P

  20. Mechanisms of heme utilization by Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Helena Lindgren

    Full Text Available Francisella tularensis is a highly virulent facultative intracellular pathogen causing the severe disease tularemia in mammals. As for other bacteria, iron is essential for its growth but very few mechanisms for iron acquisition have been identified. Here, we analyzed if and how F. tularensis can utilize heme, a major source of iron in vivo. This is by no means obvious since the bacterium lacks components of traditional heme-uptake systems. We show that SCHU S4, the prototypic strain of subspecies tularensis, grew in vitro with heme as the sole iron source. By screening a SCHU S4 transposon insertion library, 16 genes were identified as important to efficiently utilize heme, two of which were required to avoid heme toxicity. None of the identified genes appeared to encode components of a potential heme-uptake apparatus. Analysis of SCHU S4 deletion mutants revealed that each of the components FeoB, the siderophore system, and FupA, contributed to the heme-dependent growth. In the case of the former two systems, iron acquisition was impaired, whereas the absence of FupA did not affect iron uptake but led to abnormally high binding of iron to macromolecules. Overall, the present study demonstrates that heme supports growth of F. tularensis and that the requirements for the utilization are highly complex and to some extent novel.

  1. Heme oxygenase: evolution, structure, and mechanism. (United States)

    Wilks, Angela


    Heme oxygenase has evolved to carry out the oxidative cleavage of heme, a reaction essential in physiological processes as diverse as iron reutilization and cellular signaling in mammals, synthesis of essential light-harvesting pigments in cyanobacteria and higher plants, and the acquisition of iron by bacterial pathogens. In all of these processes, heme oxygenase has evolved a similar structural and mechanistic scaffold to function within seemingly diverse physiological pathways. The heme oxygenase reaction is catalytically distinct from that of other hemoproteins such as the cytochromes P450, peroxidases, and catalases, but shares a hemoprotein scaffold that has evolved to generate a distinct activated oxygen species. In the following review we discuss the evolution of the structural and functional properties of heme oxygenase in light of the recent crystal structures of the mammalian and bacterial enzymes.

  2. Distinct patterns of cytokine regulation in discrete clinical forms of Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Akanmori, B D; Kurtzhals, J A; Goka, B Q;


    The pathogenesis of two of the most severe complications of Plasmodium falciparum malaria, cerebral malaria (CM) and severe malarial anaemia (SA) both appear to involve dysregulation of the immune system. We have measured plasma levels of TNF and its two receptors in Ghanaian children with strictly...... defined cerebral malaria (CM), severe malarial anaemia (SA), or uncomplicated malaria (UM) in two independent studies in an area of seasonal, hyperendemic transmission of P. falciparum. Levels of TNF, soluble TNF receptor 1 (sTNF-R1) and 2 (sTNF-R2) were found to be significantly higher in CM than...... in the other clinical categories of P. falciparum malaria patients. Levels of both receptors depended on clinical category, whereas only sTNF-R1 levels were significantly dependent on parasitemia. Detailed analysis of the interrelationship between these variables resolved this pattern further, and identified...

  3. Differential effects of heme oxygenase isoforms on heme mediation of endothelial intracellular adhesion molecule 1 expression. (United States)

    Wagener, F A; da Silva, J L; Farley, T; de Witte, T; Kappas, A; Abraham, N G


    Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular hemoprotein, hemoglobin, and heme; the latter generates pro-oxidant products, including free radicals. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible isoform, whereas HO-2 is suggested to be constitutively expressed. We studied the inducing effect of several metal compounds (CoCl(2), stannic mesoporphyrin, and heme) on HO activity. Additionally, we studied HO-1 expression in experimental models of adhesion molecule expression produced by heme in endothelial cells, and the relationship of HO-1 expression to the induced adhesion molecules. Flow cytometry analysis showed that heme induces intracellular adhesion molecule 1 (ICAM-1) expression in a concentration (10-100 microM)- and time (1-24 h)-dependent fashion in human umbilical vein endothelial cells. Pretreatment with stannic mesoporphyrin, an inhibitor of HO activity, caused a 2-fold increase in heme-induced ICAM-1 expression. In contrast, HO induction by CoCl(2) decreased heme-induced ICAM-1 expression by 33%. To examine the contribution of HO-1 and HO-2 to endothelial HO activity, specific antisense oligonucleotides (ODNs) of each isoform were tested for their specificity to inhibit HO activity in cells exposed to heme. Endothelial cells exposed to heme elicited increased HO activity, which was prevented (70%) by HO-1 antisense ODNs. HO-2 antisense ODN inhibited heme-induced HO activity by 21%. Addition of HO-1 antisense ODNs prevented heme degradation and resulted in elevation of microsomal heme. Western blot analysis showed that HO-1 antisense ODNs selectively inhibited HO-1 protein and failed to inhibit HO-2 protein. Incubation of endothelial cells with HO-1 antisense enhanced heme-dependent increase of ICAM-1. In contrast, addition of HO-2 antisense to endothelial cells failed to increase adhesion molecules. The role of glutathione, an important antioxidant, was examined on heme

  4. Heme sensing in Bacillus thuringiensis: a supplementary HssRS-regulated heme resistance system. (United States)

    Schmidt, Rachel M; Carter, Micaela M; Chu, Michelle L; Latario, Casey J; Stadler, Sarah K; Stauff, Devin L


    Several Gram-positive pathogens scavenge host-derived heme to satisfy their nutritional iron requirement. However, heme is a toxic molecule capable of damaging the bacterial cell. Gram-positive pathogens within the phylum Firmicutes overcome heme toxicity by sensing heme through HssRS, a two-component system that regulates the heme detoxification transporter HrtAB. Here we show that heme sensing by HssRS and heme detoxification by HrtAB occur in the insect pathogen Bacillus thuringiensis We find that in B. thuringiensis, HssRS directly regulates an operon, hrmXY, encoding hypothetical membrane proteins that are not found in other Firmicutes with characterized HssRS and HrtAB systems. This novel HssRS-regulated operon or its orthologs BMB171_c3178 and BMB171_c3330 are required for maximal heme resistance. Furthermore, the activity of HrmXY is not dependent on expression of HrtAB. These results suggest that B. thuringiensis senses heme through HssRS and induces expression of separate membrane-localized systems capable of overcoming different aspects of heme toxicity.

  5. Ataque cerebral


    Takeuchi Tan, Yuri; Fundación Valle de Lili


    ¿Qué es un ataque cerebral?/¿Qué tipos de ataque cerebral existen?/¿Cuáles son los síntomas de un ataque cerebral?/Factores de riesgo para un ataque cerebral/Tratamiento médico del ataque cerebral/¿por qué es importante acudir temprano cuando se presentan las señales de alarma?/ Manejo preventivo del ataque cerebral isquémico/Tratamiento quirúrgico del ataque cerebral/Enfermedad vascular cerebral hemorrágica/¿Cómo está constituido el grupo de ataque cerebral de la fundación Clínica Valle d...

  6. Free heme and sickle hemoglobin polymerization (United States)

    Uzunova, Veselina V.

    This work investigates further the mechanism of one of the most interesting of the protein self-assembly systems---the polymerization of sickle hemoglobin and the role of free heme in it. Polymerization of sickle hemoglobin is the primary event in the pathology of a chronic hemolytic condition called sickle cell anemia with complex pathogenesis, unexplained variability and symptomatic treatment. Auto-oxidation develops in hemoglobin solutions exposed to room temperature and causes release of ferriheme. The composition of such solutions is investigated by mass spectrometry. Heme dimers whose amount corresponds to the initial amounts of heme released from the protein are followed. Differences in the dimer peak height are established for hemoglobin variants A, S and C and depending on the exposure duration. The effects of free heme on polymerization kinetics are studied. Growth rates and two characteristic parameters of nucleation are measured for stored Hb S. After dialysis of polymerizing solutions, no spherulites are detected at moderately high supersaturation and prolonged exposure times. The addition of 0.16-0.26 mM amounts of heme to dialyzed solutions leads to restoration of polymerization. The measured kinetic parameters have higher values compared to the ones before dialysis. The amount of heme in non-dialyzed aged solution is characterized using spectrophotometry. Three methods are used: difference in absorbance of dialyzed and non-dialyzed solutions, characteristic absorbance of heme-albumin complex and absorbance of non-dialyzed solutions with added potassium cyanide. The various approaches suggest the presence of 0.12 to 0.18 mM of free ferriheme in such solutions. Open questions are whether the same amounts of free heme are present in vivo and whether the same mechanism operates intracellulary. If the answer to those questions is positive, then removal of free heme from erythrocytes can influence their readiness to sickle.

  7. Porphyrin and heme metabolism and the porphyrias. (United States)

    Bonkovsky, Herbert L; Guo, Jun-Tao; Hou, Weihong; Li, Ting; Narang, Tarun; Thapar, Manish


    Porphyrins and metalloporphyrins are the key pigments of life on earth as we know it, because they include chlorophyll (a magnesium-containing metalloporphyrin) and heme (iron protoporphyrin). In eukaryotes, porphyrins and heme are synthesized by a multistep pathway that involves eight enzymes. The first and rate-controlling step is the formation of delta-aminolevulinic acid (ALA) from glycine plus succinyl CoA, catalyzed by ALA synthase. Intermediate steps occur in the cytoplasm, with formation of the monopyrrole porphobilinogen and the tetrapyrroles hydroxymethylbilane and a series of porphyrinogens, which are serially decarboxylated. Heme is utilized chiefly for the formation of hemoglobin in erythrocytes, myoglobin in muscle cells, cytochromes P-450 and mitochondrial cytochromes, and other hemoproteins in hepatocytes. The rate-controlling step of heme breakdown is catalyzed by heme oxygenase (HMOX), of which there are two isoforms, called HMOX1 and HMOX2. HMOX breaks down heme to form biliverdin, carbon monoxide, and iron. The porphyrias are a group of disorders, mainly inherited, in which there are defects in normal porphyrin and heme synthesis. The cardinal clinical features are cutaneous (due to the skin-damaging effects of excess deposited porphyrins) or neurovisceral attacks of pain, sometimes with weakness, delirium, seizures, and the like (probably due mainly to neurotoxic effects of ALA). The treatment of choice for the acute hepatic porphyrias is intravenous heme therapy, which repletes a critical regulatory heme pool in hepatocytes and leads to downregulation of hepatic ALA synthase, which is a biochemical hallmark of all forms of acute porphyria in relapse.

  8. Heme environment in HmuY, the heme-binding protein of Porphyromonas gingivalis

    Energy Technology Data Exchange (ETDEWEB)

    Wojtowicz, Halina [Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Tamka 2, 50-137 Wroclaw (Poland); Wojaczynski, Jacek [Department of Chemistry, University of Wroclaw, 50-383 Wroclaw (Poland); Olczak, Mariusz [Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Tamka 2, 50-137 Wroclaw (Poland); Kroliczewski, Jaroslaw [Laboratory of Biophysics, Faculty of Biotechnology, University of Wroclaw, 50-148 Wroclaw (Poland); Latos-Grazynski, Lechoslaw [Department of Chemistry, University of Wroclaw, 50-383 Wroclaw (Poland); Olczak, Teresa, E-mail: [Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Tamka 2, 50-137 Wroclaw (Poland)


    Porphyromonas gingivalis, a Gram-negative anaerobic bacterium implicated in the development and progression of chronic periodontitis, acquires heme for growth by a novel mechanism composed of HmuY and HmuR proteins. The aim of this study was to characterize the nature of heme binding to HmuY. The protein was expressed, purified and detailed investigations using UV-vis absorption, CD, MCD, and {sup 1}H NMR spectroscopy were carried out. Ferric heme bound to HmuY may be reduced by sodium dithionite and re-oxidized by potassium ferricyanide. Heme complexed to HmuY, with a midpoint potential of 136 mV, is in a low-spin Fe(III) hexa-coordinate environment. Analysis of heme binding to several single and double HmuY mutants with the methionine, histidine, cysteine, or tyrosine residues replaced by an alanine residue identified histidines 134 and 166 as potential heme ligands.

  9. Short report: Role of viruses in Kenyan children presenting with acute encephalopathy in a malaria-endemic area

    NARCIS (Netherlands)

    C.D. Schubart; N. Mturi; M.G.H.M. Beld; P.M. Wertheim; C.R.J.C. Newton


    In malaria-endemic areas, it is difficult to differentiate between cerebral malaria (CM), bacterial meningitis, and viral encephalitis. We examined the cerebrospinal fluid of 49 children who fulfilled the World Health Organization's (WHO) definition of CM and in 47 encephalopathic children, without

  10. Transcriptional profile of Haemophilus influenzae: effects of iron and heme. (United States)

    Whitby, Paul W; Vanwagoner, Timothy M; Seale, Thomas W; Morton, Daniel J; Stull, Terrence L


    Haemophilus influenzae requires either heme or a porphyrin and iron source for growth. Microarray studies of H. influenzae strain Rd KW20 identified 162 iron/heme-regulated genes, representing approximately 10% of the genome, with > or =1.5-fold changes in transcription in response to iron/heme availability in vitro. Eighty genes were preferentially expressed under iron/heme restriction; 82 genes were preferentially expressed under iron/heme-replete conditions.

  11. Utility of heme analogues to intentionally modify heme-globin interactions in myoglobin. (United States)

    Neya, Saburo; Nagai, Masako; Nagatomo, Shigenori; Hoshino, Tyuji; Yoneda, Tomoki; Kawaguchi, Akira T


    Myoglobin reconstitution with various synthetic heme analogues was reviewed to follow the consequences of modified heme-globin interactions. Utility of dimethyl sulfoxide as the solvent for water-insoluble hemes was emphasized. Proton NMR spectroscopy revealed that loose heme-globin contacts in the heme pocket eventually caused the dynamic heme rotation around the iron-histidine bond. The full rotational rate was estimated to be about 1400 s(-1) at room temperature for 1,4,5,8-tetramethylhemin. The X-ray analysis of the myoglobin containing iron porphine, the smallest heme without any side chains, showed that the original globin fold was well conserved despite the serious disruption of native heme-globin contacts. Comparison between the two myoglobins with static and rotatory prosthetic groups indicated that the oxygen and carbon monoxide binding profiles were almost unaffected by the heme motion. On the other hand, altered tetrapyrrole array of porphyrin dramatically changed the dissociation constant of oxygen from 0.0005 mm Hg of porphycene-myoglobin to ∞ in oxypyriporphyrin-myoglobin. Heme-globin interactions in myoglobin were also monitored with circular dichroism spectroscopy. The observation on several reconstituted protein revealed an unrecognized role of the propionate groups in protoheme. Shortening of heme 6,7-propionates to carboxylates resulted in almost complete disappearance of the positive circular dichroism band in the Soret region. The theoretical analysis suggested that the disappeared circular dichroism band reflected the cancellation effects between different conformers of the carboxyl groups directly attached to heme periphery. The above techniques were proposed to be applicable to other hemoproteins to create new biocatalysts. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.

  12. Malaria og graviditet

    DEFF Research Database (Denmark)

    Hoffmann, A L; Rønn, A M; Langhoff-Roos, J


    In regions where malaria is endemism, the disease is a recognised cause of complications of pregnancy such as spontaneous abortion, premature delivery, intrauterine growth retardation and foetal death. Malaria is seldom seen in pregnant women in Denmark but, during the past two years, the authors...... the patients but also their practitioners were unaware that malaria can occur several years after exposure. Three out of the four patients had employed malaria prophylaxis. As resistance to malarial prophylactics in current use is increasing steadily, chemoprophylaxis should be supplemented by mechanical...... protection against malaria and insect repellents. As a rule, malaria is treated with chloroquine. In cases of Falciparum malaria in whom chloroquine resistance is suspected, treatment with mefloquine may be employed although this should only be employed in cases of dire necessity in pregnant patients during...

  13. In-Cell Enzymology To Probe His-Heme Ligation in Heme Oxygenase Catalysis. (United States)

    Sigala, Paul A; Morante, Koldo; Tsumoto, Kouhei; Caaveiro, Jose M M; Goldberg, Daniel E


    Heme oxygenase (HO) is a ubiquitous enzyme with key roles in inflammation, cell signaling, heme disposal, and iron acquisition. HO catalyzes the oxidative conversion of heme to biliverdin (BV) using a conserved histidine to coordinate the iron atom of bound heme. This His-heme interaction has been regarded as being essential for enzyme activity, because His-to-Ala mutants fail to convert heme to biliverdin in vitro. We probed a panel of proximal His mutants of cyanobacterial, human, and plant HO enzymes using a live-cell activity assay based on heterologous co-expression in Escherichia coli of each HO mutant and a fluorescent biliverdin biosensor. In contrast to in vitro studies with purified proteins, we observed that multiple HO mutants retained significant activity within the intracellular environment of bacteria. X-ray crystallographic structures of human HO1 H25R with bound heme and additional functional studies suggest that HO mutant activity inside these cells does not involve heme ligation by a proximal amino acid. Our study reveals unexpected plasticity in the active site binding interactions with heme that can support HO activity within cells, suggests important contributions by the surrounding active site environment to HO catalysis, and can guide efforts to understand the evolution and divergence of HO function.

  14. Spectroscopic characterization of a higher plant heme oxygenase isoform-1 from Glycine max (soybean)--coordination structure of the heme complex and catabolism of heme. (United States)

    Gohya, Tomohiko; Zhang, Xuhong; Yoshida, Tadashi; Migita, Catharina T


    Heme oxygenase converts heme into biliverdin, CO, and free iron. In plants, as well as in cyanobacteria, heme oxygenase plays a particular role in the biosynthesis of photoreceptive pigments, such as phytochromobilins and phycobilins, supplying biliverdin IX(alpha) as a direct synthetic resource. In this study, a higher plant heme oxygenase, GmHO-1, of Glycine max (soybean), was prepared to evaluate the molecular features of its heme complex, the enzymatic activity, and the mechanism of heme conversion. The similarity in the amino acid sequence between GmHO-1 and heme oxygenases from other biological species is low, and GmHO-1 binds heme with 1 : 1 stoichiometry at His30; this position does not correspond to the proximal histidine of other heme oxygenases in their sequence alignments. The heme bound to GmHO-1, in the ferric high-spin state, exhibits an acid-base transition and is converted to biliverdin IX(alpha) in the presence of NADPH/ferredoxin reductase/ferredoxin, or ascorbate. During the heme conversion, an intermediate with an absorption maximum different from that of typical verdoheme-heme oxygenase or CO-verdoheme-heme oxygenase complexes was observed and was extracted as a bis-imidazole complex; it was identified as verdoheme. A myoglobin mutant, H64L, with high CO affinity trapped CO produced during the heme degradation. Thus, the mechanism of heme degradation by GmHO-1 appears to be similar to that of known heme oxygenases, despite the low sequence homology. The heme conversion by GmHO-1 is as fast as that by SynHO-1 in the presence of NADPH/ferredoxin reductase/ferredoxin, thereby suggesting that the latter is the physiologic electron-donating system.

  15. Malaria pigment crystals as magnetic micro-rotors: key for high-sensitivity diagnosis

    CERN Document Server

    Butykai, A; Kocsis, V; Szaller, D; Bordacs, S; Tatrai-Szekeres, E; Kiss, L F; Bota, A; Vertessy, B G; Zelles, T; Kezsmarki, I


    The need to develop new methods for the high-sensitivity diagnosis of malaria has initiated a global activity in medical and interdisciplinary sciences. Most of the diverse variety of emerging techniques are based on research-grade instruments, sophisticated reagent-based assays or rely on expertise. Here, we suggest an alternative optical methodology with an easy-to-use and cost-effective instrumentation, which takes advantage of the unique properties of malaria pigment revealed in the present study. Malaria pigment, also called hemozoin, is an insoluble microcrystalline form of heme. We found that these crystallites show remarkable magnetic and optical anisotropy distinctly from any other components of blood. In suspensions they can simultaneously act as magnetically driven micro-rotors and spinning polarizers. These properties can gain fundamental importance not only in the diagnosis of malaria and in therapies, where hemozoin is considered as drug target or immune modulator, but generally in the magnetic ...

  16. Cerebral Palsy (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 ...

  17. Pathophysiological Mechanisms in Gaseous Therapies for Severe Malaria. (United States)

    Kayano, Ana Carolina A V; Dos-Santos, João Conrado K; Bastos, Marcele F; Carvalho, Leonardo J; Aliberti, Júlio; Costa, Fabio T M


    Over 200 million people worldwide suffer from malaria every year, a disease that causes 584,000 deaths annually. In recent years, significant improvements have been achieved on the treatment of severe malaria, with intravenous artesunate proving superior to quinine. However, mortality remains high, at 8% in children and 15% in adults in clinical trials, and even worse in the case of cerebral malaria (18% and 30%, respectively). Moreover, some individuals who do not succumb to severe malaria present long-term cognitive deficits. These observations indicate that strategies focused only on parasite killing fail to prevent neurological complications and deaths associated with severe malaria, possibly because clinical complications are associated in part with a cerebrovascular dysfunction. Consequently, different adjunctive therapies aimed at modulating malaria pathophysiological processes are currently being tested. However, none of these therapies has shown unequivocal evidence in improving patient clinical status. Recently, key studies have shown that gaseous therapies based mainly on nitric oxide (NO), carbon monoxide (CO), and hyperbaric (pressurized) oxygen (HBO) alter vascular endothelium dysfunction and modulate the host immune response to infection. Considering gaseous administration as a promising adjunctive treatment against severe malaria cases, we review here the pathophysiological mechanisms and the immunological aspects of such therapies.


    Directory of Open Access Journals (Sweden)

    Shekhawat G. S.


    Full Text Available In recent years role of Heme oxygenase (HO has been considered in nearly all living system including plants, animals and other organisms. The common role of heme oxygenase is the degradation of heme, although there is a diversity of additional role of HO in organisms including iron acquisition, cellular signaling, defense against stress and biosynthesis during metabolism. Likewise, the function of HO is to provide cofactors for the photosynthetic apparatus in cyanobacteria. Heme concentration is variable in different plant species and found maximum in leguminous plant root nodules. Moreover HO has diverse isoforms in plant and animal systems. The review addressed important function of HO and focused on its functional diversity.

  19. Structural mechanisms of nonplanar hemes in proteins

    Energy Technology Data Exchange (ETDEWEB)

    Shelnutt, J.A.


    The objective is to assess the occurrence of nonplanar distortions of hemes and other tetrapyrroles in proteins and to determine the biological function of these distortions. Recently, these distortions were found by us to be conserved among proteins belonging to a functional class. Conservation of the conformation of the heme indicates a possible functional role. Researchers have suggested possible mechanisms by which heme distortions might influence biological properties; however, no heme distortion has yet been shown conclusively to participate in a structural mechanism of hemoprotein function. The specific aims of the proposed work are: (1) to characterize and quantify the distortions of the hemes in all of the more than 300 hemoprotein X-ray crystal structures in terms of displacements along the lowest-frequency normal coordinates, (2) to determine the structural features of the protein component that generate and control these nonplanar distortions by using spectroscopic studies and molecular-mechanics calculations for the native proteins, their mutants and heme-peptide fragments, and model porphyrins, (3) to determine spectroscopic markers for the various types of distortion, and, finally, (4) to discover the functional significance of the nonplanar distortions by correlating function with porphyrin conformation for proteins and model porphyrins.

  20. Crystal structure of dimeric heme oxygenase-2 from Synechocystis sp. PCC 6803 in complex with heme. (United States)

    Sugishima, Masakazu; Hagiwara, Yoshinori; Zhang, Xuhong; Yoshida, Tadashi; Migita, Catharina T; Fukuyama, Keiichi


    Phycobiliproteins, light-harvesting proteins in cyanobacteria, red algae, and cryptophytes, contain phycobilin pigments. Phycobilins are synthesized from biliverdin, which is produced by the oxidative cleavage of the heme porphyrin ring catalyzed by heme oxygenase (HO). Two paralogs of ho (ho1 and ho2) have been identified in the genome of the cyanobacterium, Synechocystis sp. PCC 6803. The recombinant proteins of both paralogs (Syn HO-1 and Syn HO-2) possess in vitro heme degradation activity. We have determined the crystal structures of Syn HO-2 in complex with heme (heme-Syn HO-2) and its reduced and NO bound forms. The heme-Syn HO-2 crystal was a nonmerohedral twin, and detwinned diffraction data were used to refine the structure. Although heme-Syn HO-2 shares common folding with other HOs, the C-terminal segment is ordered and turns back to the heme-binding side. Gel-filtration chromatography analysis and molecular packing in the crystal indicate that heme-Syn HO-2 forms a homodimer, in which the C-terminal ordered segments interact with each other. Because Syn HO-2 is a monomer in the apo state, the dimeric interaction may aid in the selection of the reducing partner but likely does not interfere with heme binding. The heme iron is coordinated by a water molecule in the ferric form, but the distal water is absent in the ferrous form. In all of the Syn HO-2 structures, several water molecules form a hydrogen-bond network at the distal hemepocket, which is involved in HO activity. Upon NO binding, the side-chain conformation of Tyr 156 changes. Tyr 156 is located at the hydrophobic cluster, which interrupts the possible H(+) pathway from the molecular surface to the hemepocket. Thus, Tyr 156 may function as a H(+) shuttle by changing conformation.

  1. Identification of the receptor scavenging hemopexin-heme complexes

    DEFF Research Database (Denmark)

    Hvidberg, Vibeke; Maniecki, Maciej B; Jacobsen, Christian;


    and is suggested to facilitate cellular heme metabolism. Using a ligand-affinity approach, we purified the human hemopexin-heme receptor and identified it as the low-density lipoprotein receptor-related protein (LRP)/CD91, a receptor expressed in several cell types including macrophages, hepatocytes, neurons......, and syncytiotrophoblasts. Binding experiments, including Biacore analysis, showed that hemopexin-heme complex formation elicits the high receptor affinity. Uptake studies of radio-labeled hemopexin-heme complex in LRP/CD91-expressing COS cells and confocal microscopy of the cellular processing of fluorescent hemopexin......-heme complex established the ability of LRP/CD91 to mediate hemopexin-heme internalization resulting in cellular heme uptake and lysosomal hemopexin degradation. Uptake of hemopexin-heme complex induced LRP/CD91-dependent heme-oxygenase 1 mRNA transcription in cultured monocytes. In conclusion, hemopexin...

  2. Heme electron transfer in peroxidases: the propionate e-pathway. (United States)

    Guallar, Victor


    Computational modeling offers a new insight about the electron transfer pathway in heme peroxidases. Available crystal structures have revealed an intriguing arrangement of the heme propionate side chains in heme-heme and heme-substrate complexes. By means of mixed quantum mechanical/molecular mechanics calculations, we study the involvement of these propionate groups into the substrate oxidation in ascorbate peroxidase and into the heme to heme electron transfer in bacterial cytochrome c peroxidase. By selectively turning on/off different quantum regions, we obtain the electron transfer pathway which directly involves the porphyrin ring and the heme propionates. Furthermore, in ascorbate peroxidase the presence of the substrate appears to be crucial for the activation of the electron transfer channel. The results might represent a general motif for electron transfer from/to the heme group and change our view for the propionate side chains as simple electrostatic binding anchors. We name the new mechanism "the propionate e-pathway".


    Directory of Open Access Journals (Sweden)

    Sohaib Ahmad


    Full Text Available Background & Objectives: Classically associated with Plasmodium falciparum, neurological complications in severe malaria is associated with increased morbidity and mortality. However, reports implicate the long considered benign Plasmodium vivax for causing severe malaria as well. We aimed to analyze the cerebral complications in malaria, and study if there is a specie-related difference in the presentation and outcomes. Methods: We retrospectively compared patients of malaria hospitalised from 2009-15, with (n=105 and without (n=1155 neurological involvement in terms of outcomes, complications, demographic attributes, clinical features, and laboratory parameters. Subsequently, the same parameters were studied in those with cerebral malaria due to mono-infections of vivax or falciparum and their co-infection. Results: Cerebral malaria was observed in 8.3% (58/696, 7.4% (38/513 and 17.6% (6/51 of vivax, falciparum and combined plasmodial infections respectively. Those with cerebral malaria had significantly (p0.05. P. vivax emerged as the predominant cause of cerebral malaria and its virulence was comparable to P. falciparum.

  4. Heme-containing dioxygenases involved in tryptophan oxidation. (United States)

    Millett, Elizabeth S; Efimov, Igor; Basran, Jaswir; Handa, Sandeep; Mowat, Christopher G; Raven, Emma Lloyd


    Heme iron is often used in biology for activation of oxygen. The mechanisms of oxygen activation by heme-containing monooxygenases (the cytochrome P450s) are well known, and involve formation of a Compound I species, but information on the heme-containing dioxygenase enzymes involved in tryptophan oxidation lags far behind. In this review, we gather together information emerging recently from structural, mechanistic, spectroscopic, and computational approaches on the heme dioxygenase enzymes involved in tryptophan oxidation. We explore the subtleties that differentiate various heme enzymes from each other, and use this to piece together a developing picture for oxygen activation in this particular class of heme-containing dioxygenases.

  5. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts


    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

  6. ApoHRP-based Assay to Measure Intracellular Regulatory Heme (United States)

    Atamna, Hani; Brahmbhatt, Marmik; Atamna, Wafa; Shanower, Gregory A.; Dhahbi, Joseph M.


    The majority of the heme-binding proteins possess a “heme-pocket” that stably binds with heme. Usually known as housekeeping heme-proteins, they participate in a variety of metabolic reactions (e.g., catalase). Heme also binds with lower affinity to the “Heme-Regulatory Motifs” (HRM) in specific regulatory proteins. This type of heme binding is known as exchangeable or regulatory heme (RH). Heme binding to HRM proteins regulates their function (e.g., Bach1). Although there are well-established methods for assaying total cellular heme (e.g., heme-proteins plus RH), currently there is no method available for measuring RH independently from the total heme (TH). The current study describes and validates a new method to measure intracellular RH. The method is based on the reconstitution of apo-horseradish peroxidase (apoHRP) with heme to form holoHRP. The resulting holoHRP activity is then measured with a colorimetric substrate. The results show that apoHRP specifically binds RH but not with heme from housekeeping heme-proteins. The RH assay detects intracellular RH. Furthermore, using conditions that create positive (hemin) or negative (N-methyl protoporphyrin IX) controls for heme in normal human fibroblasts (IMR90), the RH assay shows that RH is dynamic and independent from TH. We also demonstrated that short-term exposure to subcytotoxic concentrations of lead (Pb), mercury (Hg), or amyloid-β(Aβ) significantly alters intracellular RH with little effect on TH. In conclusion the RH assay is an effective assay to investigate intracellular RH concentration and demonstrates that RH represents ~6% of total heme in IMR90 cells. PMID:25525887

  7. Regulation of intracellular heme trafficking revealed by subcellular reporters. (United States)

    Yuan, Xiaojing; Rietzschel, Nicole; Kwon, Hanna; Walter Nuno, Ana Beatriz; Hanna, David A; Phillips, John D; Raven, Emma L; Reddi, Amit R; Hamza, Iqbal


    Heme is an essential prosthetic group in proteins that reside in virtually every subcellular compartment performing diverse biological functions. Irrespective of whether heme is synthesized in the mitochondria or imported from the environment, this hydrophobic and potentially toxic metalloporphyrin has to be trafficked across membrane barriers, a concept heretofore poorly understood. Here we show, using subcellular-targeted, genetically encoded hemoprotein peroxidase reporters, that both extracellular and endogenous heme contribute to cellular labile heme and that extracellular heme can be transported and used in toto by hemoproteins in all six subcellular compartments examined. The reporters are robust, show large signal-to-background ratio, and provide sufficient range to detect changes in intracellular labile heme. Restoration of reporter activity by heme is organelle-specific, with the Golgi and endoplasmic reticulum being important sites for both exogenous and endogenous heme trafficking. Expression of peroxidase reporters in Caenorhabditis elegans shows that environmental heme influences labile heme in a tissue-dependent manner; reporter activity in the intestine shows a linear increase compared with muscle or hypodermis, with the lowest heme threshold in neurons. Our results demonstrate that the trafficking pathways for exogenous and endogenous heme are distinct, with intrinsic preference for specific subcellular compartments. We anticipate our results will serve as a heuristic paradigm for more sophisticated studies on heme trafficking in cellular and whole-animal models.

  8. Plasma Plasmodium falciparum histidine-rich protein-2 concentrations are associated with malaria severity and mortality in Tanzanian children.

    Directory of Open Access Journals (Sweden)

    Matthew P Rubach

    Full Text Available Plasma Plasmodium falciparum histidine-rich protein-2 (PfHRP-2 concentrations, a measure of parasite biomass, have been correlated with malaria severity in adults, but not yet in children. We measured plasma PfHRP-2 in Tanzanian children with uncomplicated (n = 61 and cerebral malaria (n = 45; 7 deaths. Median plasma PfHRP-2 concentrations were higher in cerebral malaria (1008 [IQR 342-2572] ng/mL than in uncomplicated malaria (465 [IQR 36-1426] ng/mL; p = 0.017. In cerebral malaria, natural log plasma PfHRP-2 was associated with coma depth (r = -0.42; p = 0.006 and mortality (OR: 3.0 [95% CI 1.03-8.76]; p = 0.04. In this relatively small cohort study in a mesoendemic transmission area of Africa, plasma PfHRP-2 was associated with pediatric malaria severity and mortality. Further studies among children in areas of Africa with higher malaria transmission and among children with different clinical manifestations of severe malaria will help determine the wider utility of quantitative PfHRP-2 as a measure of parasite biomass and prognosis in sub-Saharan Africa.

  9. Role of heme-protein covalent bonds in mammalian peroxidases. Protection of the heme by a single engineered heme-protein link in horseradish peroxidase. (United States)

    Huang, Liusheng; Wojciechowski, Grzegorz; Ortiz de Montellano, Paul R


    Oxidation of SCN-, Br-, and Cl- (X-) by horseradish peroxidase (HRP) and other plant and fungal peroxidases results in the addition of HOX to the heme vinyl group. This reaction is not observed with lactoperoxidase (LPO), in which the heme is covalently bound to the protein via two ester bonds between carboxylic side chains and heme methyl groups. To test the hypothesis that the heme of LPO and other mammalian peroxidases is protected from vinyl group modification by the hemeprotein covalent bonds, we prepared the F41E mutant of HRP in which the heme is attached to the protein via a covalent bond between Glu41 and the heme 3-methyl. We also examined the E375D mutant of LPO in which only one of the two normal covalent heme links is retained. The prosthetic heme groups of F41E HRP and E375D LPO are essentially not modified by the HOBr produced by these enzymes. The double E375D/D225E mutant of LPO that can form no covalent bonds is inactive and could not be examined. These results unambiguously demonstrate that a single heme-protein link is sufficient to protect the heme from vinyl group modification even in a protein (HRP) that is normally highly susceptible to this reaction. The results directly establish that one function of the covalent heme-protein bonds in mammalian peroxidases is to protect their prosthetic group from their highly reactive metabolic products.

  10. Heme and non-heme iron transporters in non-polarized and polarized cells

    Directory of Open Access Journals (Sweden)

    Yasui Yumiko


    Full Text Available Abstract Background Heme and non-heme iron from diet, and recycled iron from hemoglobin are important products of the synthesis of iron-containing molecules. In excess, iron is potentially toxic because it can produce reactive oxygen species through the Fenton reaction. Humans can absorb, transport, store, and recycle iron without an excretory system to remove excess iron. Two candidate heme transporters and two iron transporters have been reported thus far. Heme incorporated into cells is degraded by heme oxygenases (HOs, and the iron product is reutilized by the body. To specify the processes of heme uptake and degradation, and the reutilization of iron, we determined the subcellular localizations of these transporters and HOs. Results In this study, we analyzed the subcellular localizations of 2 isoenzymes of HOs, 4 isoforms of divalent metal transporter 1 (DMT1, and 2 candidate heme transporters--heme carrier protein 1 (HCP1 and heme responsive gene-1 (HRG-1--in non-polarized and polarized cells. In non-polarized cells, HCP1, HRG-1, and DMT1A-I are located in the plasma membrane. In polarized cells, they show distinct localizations: HCP1 and DMT1A-I are located in the apical membrane, whereas HRG-1 is located in the basolateral membrane and lysosome. 16Leu at DMT1A-I N-terminal cytosolic domain was found to be crucial for plasma membrane localization. HOs are located in smooth endoplasmic reticulum and colocalize with NADPH-cytochrome P450 reductase. Conclusions HCP1 and DMT1A-I are localized to the apical membrane, and HRG-1 to the basolateral membrane and lysosome. These findings suggest that HCP1 and DMT1A-I have functions in the uptake of dietary heme and non-heme iron. HRG-1 can transport endocytosed heme from the lysosome into the cytosol. These localization studies support a model in which cytosolic heme can be degraded by HOs, and the resulting iron is exported into tissue fluids via the iron transporter ferroportin 1, which is

  11. Independent evolution of four heme peroxidase superfamilies. (United States)

    Zámocký, Marcel; Hofbauer, Stefan; Schaffner, Irene; Gasselhuber, Bernhard; Nicolussi, Andrea; Soudi, Monika; Pirker, Katharina F; Furtmüller, Paul G; Obinger, Christian


    Four heme peroxidase superfamilies (peroxidase-catalase, peroxidase-cyclooxygenase, peroxidase-chlorite dismutase and peroxidase-peroxygenase superfamily) arose independently during evolution, which differ in overall fold, active site architecture and enzymatic activities. The redox cofactor is heme b or posttranslationally modified heme that is ligated by either histidine or cysteine. Heme peroxidases are found in all kingdoms of life and typically catalyze the one- and two-electron oxidation of a myriad of organic and inorganic substrates. In addition to this peroxidatic activity distinct (sub)families show pronounced catalase, cyclooxygenase, chlorite dismutase or peroxygenase activities. Here we describe the phylogeny of these four superfamilies and present the most important sequence signatures and active site architectures. The classification of families is described as well as important turning points in evolution. We show that at least three heme peroxidase superfamilies have ancient prokaryotic roots with several alternative ways of divergent evolution. In later evolutionary steps, they almost always produced highly evolved and specialized clades of peroxidases in eukaryotic kingdoms with a significant portion of such genes involved in coding various fusion proteins with novel physiological functions.

  12. Molecular hijacking of siroheme for the synthesis of heme and d1 heme. (United States)

    Bali, Shilpa; Lawrence, Andrew D; Lobo, Susana A; Saraiva, Lígia M; Golding, Bernard T; Palmer, David J; Howard, Mark J; Ferguson, Stuart J; Warren, Martin J


    Modified tetrapyrroles such as chlorophyll, heme, siroheme, vitamin B(12), coenzyme F(430), and heme d(1) underpin a wide range of essential biological functions in all domains of life, and it is therefore surprising that the syntheses of many of these life pigments remain poorly understood. It is known that the construction of the central molecular framework of modified tetrapyrroles is mediated via a common, core pathway. Herein a further branch of the modified tetrapyrrole biosynthesis pathway is described in denitrifying and sulfate-reducing bacteria as well as the Archaea. This process entails the hijacking of siroheme, the prosthetic group of sulfite and nitrite reductase, and its processing into heme and d(1) heme. The initial step in these transformations involves the decarboxylation of siroheme to give didecarboxysiroheme. For d(1) heme synthesis this intermediate has to undergo the replacement of two propionate side chains with oxygen functionalities and the introduction of a double bond into a further peripheral side chain. For heme synthesis didecarboxysiroheme is converted into Fe-coproporphyrin by oxidative loss of two acetic acid side chains. Fe-coproporphyrin is then transformed into heme by the oxidative decarboxylation of two propionate side chains. The mechanisms of these reactions are discussed and the evolutionary significance of another role for siroheme is examined.

  13. Heme Binding by Corynebacterium diphtheriae HmuT: Function and Heme Environment. (United States)

    Draganova, Elizabeth B; Akbas, Neval; Adrian, Seth A; Lukat-Rodgers, Gudrun S; Collins, Daniel P; Dawson, John H; Allen, Courtni E; Schmitt, Michael P; Rodgers, Kenton R; Dixon, Dabney W


    The heme uptake pathway (hmu) of Corynebacterium diphtheriae utilizes multiple proteins to bind and transport heme into the cell. One of these proteins, HmuT, delivers heme to the ABC transporter HmuUV. In this study, the axial ligation of the heme in ferric HmuT is probed by examination of wild-type (WT) HmuT and a series of conserved heme pocket residue mutants, H136A, Y235A, and M292A. Characterization by UV-visible, resonance Raman, and magnetic circular dichroism spectroscopies indicates that H136 and Y235 are the axial ligands in ferric HmuT. Consistent with this assignment of axial ligands, ferric WT and H136A HmuT are difficult to reduce while Y235A is reduced readily in the presence of dithionite. The FeCO Raman shifts in WT, H136A, and Y235A HmuT-CO complexes provide further evidence of the axial ligand assignments. Additionally, these frequencies provide insight into the nonbonding environment of the heme pocket. Ferrous Y235A and the Y235A-CO complex reveal that the imidazole of H136 exists in two forms, one neutral and one with imidazolate character, consistent with a hydrogen bond acceptor on the H136 side of the heme. The ferric fluoride complex of Y235A reveals the presence of at least one hydrogen bond donor on the Y235 side of the heme. Hemoglobin utilization assays showed that the axial Y235 ligand is required for heme uptake in HmuT.

  14. Non-heme induction of heme oxygenase-1 does not alter cellular iron metabolism. (United States)

    Sheftel, Alex D; Kim, Sangwon F; Ponka, Prem


    The catabolism of heme is carried out by members of the heme oxygenase (HO) family. The products of heme catabolism by HO-1 are ferrous iron, biliverdin (subsequently converted to bilirubin), and carbon monoxide. In addition to its function in the recycling of hemoglobin iron, this microsomal enzyme has been shown to protect cells in various stress models. Implicit in the reports of HO-1 cytoprotection to date are its effects on the cellular handling of heme/iron. However, the limited amount of uncommitted heme in non-erythroid cells brings to question the source of substrate for this enzyme in non-hemolytic circumstances. In the present study, HO-1 was induced by either sodium arsenite (reactive oxygen species producer) or hemin or overexpressed in the murine macrophage-like cell line, RAW 264.7. Both of the inducers elicited an increase in active HO-1; however, only hemin exposure caused an increase in the synthesis rate of the iron storage protein, ferritin. This effect of hemin was the direct result of the liberation of iron from heme by HO. Cells stably overexpressing HO-1, although protected from oxidative stress, did not display elevated basal ferritin synthesis. However, these cells did exhibit an increase in ferritin synthesis, compared with untransfected controls, in response to hemin treatment, suggesting that heme levels, and not HO-1, limit cellular heme catabolism. Our results suggest that the protection of cells from oxidative insult afforded by HO-1 is not due to the catabolism of significant amounts of cellular heme as thought previously.

  15. Kidney injury and heme oxygenase-1

    Directory of Open Access Journals (Sweden)

    Hai-xing MAI


    Full Text Available     Heme oxygenase-1 (HO-1 is one of the main pathways to degrade heme in mammals, and the main degradation products are free iron (Fe2+, carbon monoxide (CO, and bilirubin. Heme plays an important role in promoting cell survival, circulation of intracellular substrates, and immune regulation. Previous studies suggest that HO-1 pathway is an important internal factor in determining the susceptibility and severity of acute kidney injury (AKI. The induction of HO-1 expression can attenuate the severity of renal ischemia-reperfusion injury (IRI, and the inhibition of HO-1 expression will aggravate IRI. The present article summarizes the latest advances in research abroad and at home on protective mechanism by which HO-1 prevents AKI to further deepen our understanding of the role of HO-1 in the treatment of AKI.   

  16. Rapid Diagnosis of Malaria

    Directory of Open Access Journals (Sweden)

    Clinton K. Murray


    Full Text Available Malaria's global impact is expansive and includes the extremes of the healthcare system ranging from international travelers returning to nonendemic regions with tertiary referral medical care to residents in hyperendemic regions without access to medical care. Implementation of prompt and accurate diagnosis is needed to curb the expanding global impact of malaria associated with ever-increasing antimalarial drug resistance. Traditionally, malaria is diagnosed using clinical criteria and/or light microscopy even though both strategies are clearly inadequate in many healthcare settings. Hand held immunochromatographic rapid diagnostic tests (RDTs have been recognized as an ideal alternative method for diagnosing malaria. Numerous malaria RDTs have been developed and are widely available; however, an assortment of issues related to these products have become apparent. This review provides a summary of RDT including effectiveness and strategies to select the ideal RDT in varying healthcare settings.


    Directory of Open Access Journals (Sweden)

    Basawaraj G


    Full Text Available NTRODUCTION AND OBJECTIVES: Hematological and Renal alterations are seen mostly in Plasmodium falciparum infection, but P.vivax can occasionally contribute for renal, hematological impairment. Malarial ARF, Anemia, thrombocytopenia is commonly found in non - immune adults and older children with malaria. Occurrence of ARF, jaundice, anemia in severe malaria is quite common in Southeast Asia and Indian subcontinent. Several hypotheses including mechanical obstruction by infected erythrocytes, immune mediated glomerular and tubular pathology, and alterations in the renal microcirculation, lead to renal failure . METHODOLOGY: 220 patients were included in the study who are positive for malarial antigen and routine laboratory tests were like CBC, liver function tests, renal profile, peripheral smear were done at Basaveshwar Teaching and General Hospital, attached to Mahadevappa Rampure Medical College. RESULTS: 220 patients of malaria were analyzed. 60% had Plasmodium vivax, 34% had Plasmodium Falciparum and 6% had mixed infection . Complications of Plasmodium falciparum – Jaundice 47.5%, Anemia 27.5%, Renal failure 25%, Cerebral malaria 15%, ARDS 2.5%,Thrombocytopenia 5% and Hypoglycemia 5%.Complications of Plasmodium vivax - Jaundice 1.5%, Anemia 5.3%, Renal failure 6%. Cerebral malaria occurred in 2.7% of cases. Predominant presentations were altered behaviour, loss of consciousness, 28.5% of mixed malaria and 2.6% of PF patients had cerebral malaria. INTER PRETATION AND CONCLUSION: Malaria being a common infectious disease encountered in day to day practice, early recognition and prom p t intervention of complications due to malaria is necessary. Mainstay of treatment consists of appropriate antimalarial drug therapy, fluid replacement, and renal replacement therapy if needed and correction of anemia, thrombocytopenia.

  18. Red meat and colon cancer : how dietary heme initiates hyperproliferation

    NARCIS (Netherlands)

    IJssennagger, N.


    Colorectal cancer is a leading cause of cancer deaths in Western countries. The risk to develop colorectal cancer is associated with the intake of red meat. Red meat contains the porphyrin pigment heme. Heme is an irritant for the colonic wall and it is previously shown that the addition of heme to

  19. Molecular Simulations of Porphyrins and Heme Proteins

    Energy Technology Data Exchange (ETDEWEB)



    An overview of the use of classical mechanical molecular simulations of porphyrins, hydroporphyrins, and heme proteins is given. The topics cover molecular mechanics calculations of structures and conformer energies of porphyrins, energies of barriers for interconversion between stable conformers, molecular dynamics of porphyrins and heme proteins, and normal-coordinate structural analysis of experimental and calculated porphyrin structures. Molecular mechanics and dynamics are currently a fertile area of research on porphyrins. In the future, other computational methods such as Monte Carlo simulations, which have yet to be applied to porphyrins, will come into use and open new avenues of research into molecular simulations of porphyrins.

  20. Heme oxygenase-1 system and gastrointestinal tumors

    Institute of Scientific and Technical Information of China (English)

    Marie; CM; Lin; Hsiangfu; Kung


    Heme oxygenase-1(HO-1) system catabolizes heme into three products:carbon monoxide,biliverdin/bilirubin and free iron.It is involved in many physiological and pathophysiological processes.A great deal of data has demonstrated the roles of HO-1 in the formation,growth and metastasis of tumors.The interest in this system by investigators involved in gastrointestinal tumors is fairly recent,and few papers on HO-1 have touched upon this subject.This review focuses on the current understanding of the physiologic...

  1. Analysis of Heme oxygenase isomers in rat

    Institute of Scientific and Technical Information of China (English)

    Yun-ZhuLi; Wen-JunCui; Xue-HongZhang; Qing-XiangShen; JianWang; She


    AIM:To purify and identify heme oxygenase(HO) isomers which exist in rat liver,spleen and brain treated with hematin and phenylhydrazine and in untrated rat liver and to investigate the characteristics of HO isomers,to isolate and confirm the rat HO-1 cDNA that actually encodes HO-1 by expressing cDNA in monkey Kidney cells(COS-1 cells),to prepare the rat heme oxygenase-1(HO-1)mutant and to detect inhibition of HO-1 mutated enzyme.


    Directory of Open Access Journals (Sweden)

    Valluri Satya


    Full Text Available The clinical pattern of malaria has changed worldwide including India in last decade. Earlier cerebral malaria was the predominant manifestation of severe malaria, whereas now the combination of jaundice and renal failure are more common. Severe haemorrhage is seen in upto 5% of patients with severe malaria. Studies on renal and hepatic dys function in Plasmodium falciparum malaria are a plenty, but there is a paucity of studies correlating haemorrheological abnormalities with hepatic and renal dysfunction in Plasmodium falciparum malaria. METHODS : 100 patients of malaria with positive periph eral blood smear for plasmodium falciparum , out of which 50 cases with AKI and Hepatic failure during the period January 2012 - June 2013. I n department of general medicine, Government General Hospital, Kakinada. GROUP A : Comprising 50 consecutive adult pat ients of all age groups and both genders who had jaundice or renal failure or both at the time of admission. GROUP B: comprising 50 consecutive cases of plasmodium falciparum malaria and had no complications. RESULTS: In group A patients all parameters are significantly raised as compared to group B patients. CONCLUSION: 10% of patients had clinically overt bleeding manifestations, this indicates subclinical haemorrheological dysfunction in patients suffering from falciparum malaria with hepatic and renal d ysfunction, high incidence of subclinical DIC, evidenced by prolonged aPTT (56%, low total platelet count (58%, and PT (20%. An observational, screening, analytical prospective study. 100 cases of PF positive complicated and uncomplicated cases during t he period - January 2012 - June 2013

  3. Audit of imported and domestic malaria cases at Kuala Lumpur Hospital. (United States)

    Moore, C S; Cheong, I


    The clinical, haematological and biochemical profiles of all domestic and imported malaria cases admitted to the Hospital Kuala Lumpur were analysed. The most common malaria types were Plasmodium falciparum (39.5%) and Plasmodium vivax (42%). The most common patient type was men aged 29-40 years (reflecting the high mobility of this group, many of whom were illegal immigrants). Misdiagnosis on admission was frequently due to the variable clinical presentation of the disease and the difficulties of obtaining an accurate history. Associated haematological abnormalities were common. Chloroquine resistance was diagnosed in four P. falciparum patients and in one P. falciparum/vivax patient. Overall, imported malaria did not seem more severe than domestic. The three patients with cerebral malaria survived. One patient died of acute liver failure. The large influx of illegal immigrants to Malaysia has resulted in a surge in malaria infection; illegal immigrants remain a source of chloroquine resistance.

  4. Plasmodium falciparum erythrocyte membrane protein 1 domain cassettes 8 and 13 are associated with severe malaria in children

    DEFF Research Database (Denmark)

    Lavstsen, Thomas; Turner, Louise; Saguti, Fredy


    on the surface of infected erythrocytes to anchor these to the vascular lining. Although var2csa, the var gene encoding the PfEMP1 associated with placental malaria, was discovered in 2003, the identification of the var/PfEMP1 variants associated with severe malaria in children has remained elusive. To identify...... var/PfEMP1 variants associated with severe disease outcome, we compared var transcript levels in parasites from 88 children with severe malaria and 40 children admitted to the hospital with uncomplicated malaria. Transcript analysis was performed by RT-quantitative PCR using a set of 42 primer pairs...... amplifying var subtype-specific loci covering most var/PfEMP1 subtypes. In addition, we characterized the near-full-length sequence of the most prominently expressed var genes in three patients diagnosed with severe anemia and/or cerebral malaria. The combined analysis showed that severe malaria syndromes...


    Directory of Open Access Journals (Sweden)

    Richard-Fabian Schumacher


    Full Text Available

    This review is focused on childhood specific aspects of malaria, especially in resource-poor settings. We summarise the actual knowledge in the field of epidemiology, clinical presentation, diagnosis, management and prevention.

    These aspects are important as malaria is responsible for almost a quarter of all child death in sub-Saharan Africa. Malaria control is thus one key intervention to reduce childhood mortality, especially as malaria is also an important risk factor for other severe infections, namely bacteraemia.

    In children symptoms are more varied and often mimic other common childhood illness, particularly gastroenteritis, meningitis/encephalitis, or pneumonia. Fever is the key symptom, but the characteristic regular tertian and quartan patterns are rarely observed. There are no pathognomonic features for severe malaria in this age group. The well known clinical (fever, impaired consciousness, seizures, vomiting, respiratory distress and laboratory (severe anaemia, thrombocytopenia, hypoglycaemia, metabolic acidosis, and hyperlactataemia features of severe falciparum malaria in children, are equally typical for severe sepsis.

    Appropriate therapy (considering species, resistance patterns and individual patient factors – possibly a drug combination of an artemisinin derivative with a long-acting antimalarial drug - reduces treatment duration to only three days and should be urgently started.

    While waiting for the results of ongoing vaccine trials, all effort should be made to better implement other malaria-control measures like the use of treated bed-nets and new chemoprophylaxis regimens.


    Directory of Open Access Journals (Sweden)

    Richard-Fabian Schumacher


    Full Text Available This review is focused on childhood specific aspects of malaria, especially in resource-poor settings. We summarise the actual knowledge in the field of epidemiology, clinical presentation, diagnosis, management and prevention. These aspects are important as malaria is responsible for almost a quarter of all child death in sub-Saharan Africa. Malaria control is thus one key intervention to reduce childhood mortality, especially as malaria is also an important risk factor for other severe infections, namely bacteraemia. In children symptoms are more varied and often mimic other common childhood illness, particularly gastroenteritis, meningitis/encephalitis, or pneumonia. Fever is the key symptom, but the characteristic regular tertian and quartan patterns are rarely observed. There are no pathognomonic features for severe malaria in this age group. The well known clinical (fever, impaired consciousness, seizures, vomiting, respiratory distress and laboratory (severe anaemia, thrombocytopenia, hypoglycaemia, metabolic acidosis, and hyperlactataemia features of severe falciparum malaria in children, are equally typical for severe sepsis. Appropriate therapy (considering species, resistance patterns and individual patient factors – possibly a drug combination of an artemisinin derivative with a long-acting antimalarial drug - reduces treatment duration to only three days and should be urgently started. While waiting for the results of ongoing vaccine trials, all effort should be made to better implement other malaria-control measures like the use of treated bed-nets and new chemoprophylaxis regimens.

  7. [Malaria in Algerian Sahara]. (United States)

    Hammadi, D; Boubidi, S C; Chaib, S E; Saber, A; Khechache, Y; Gasmi, M; Harrat, Z


    Thanks to the malaria eradication campaign launched in Algeria in 1968, the number of malaria cases fell down significantly from 95,424 cases in 1960 to 30 cases in 1978. At that time the northern part of the country was declared free of Plasmodium falciparum. Only few cases belonging to P. vivax persisted in residual foci in the middle part of the country. In the beginning of the eighties, the south of the country was marked by an increase of imported malaria cases. The resurgence of the disease in the oases coincided with the opening of the Trans-Saharan road and the booming trade with the neighbouring southern countries. Several authors insisted on the risk of introduction of malaria or its exotic potential vectors in Algeria via this new road. Now, the totality of malaria autochthonous cases in Algeria are located in the south of the country where 300 cases were declared during the period (1980-2007). The recent outbreak recorded in 2007 at the borders with Mall and the introduction of Anopheles gambiae into the Algerian territory show the vulnerability of this area to malaria which is probably emphasized by the local environmental changes. The authors assess the evolution of malaria in the Sahara region and draw up the distribution of the anopheles in this area.

  8. Molecular hijacking of siroheme for the synthesis of heme and d1 heme


    Bali, Shilpa; Lawrence, Andrew D.; Lobo, Susana A; Saraiva, Lígia M.; Golding, Bernard T.; Palmer, David J.; Mark J. Howard; Ferguson, Stuart J.; Warren, Martin J.


    Modified tetrapyrroles such as chlorophyll, heme, siroheme, vitamin B12, coenzyme F430, and heme d1 underpin a wide range of essential biological functions in all domains of life, and it is therefore surprising that the syntheses of many of these life pigments remain poorly understood. It is known that the construction of the central molecular framework of modified tetrapyrroles is mediated via a common, core pathway. Herein a further branch of the modified tetrapyrrole biosynthesis pathway i...

  9. Inhibition of Heme Peroxidases by Melamine

    Directory of Open Access Journals (Sweden)

    Pattaraporn Vanachayangkul


    Full Text Available In 2008 melamine-contaminated infant formula and dairy products in China led to over 50,000 hospitalizations of children due to renal injuries. In North America during 2007 and in Asia during 2004, melamine-contaminated pet food products resulted in numerous pet deaths due to renal failure. Animal studies have confirmed the potent renal toxicity of melamine combined with cyanuric acid. We showed previously that the solubility of melamine cyanurate is low at physiologic pH and ionic strength, provoking us to speculate how toxic levels of these compounds could be transported through the circulation without crystallizing until passing into the renal filtrate. We hypothesized that melamine might be sequestered by heme proteins, which could interfere with heme enzyme activity. Four heme peroxidase enzymes were selected for study: horseradish peroxidase (HRP, lactoperoxidase (LPO, and cyclooxygenase-1 and -2 (COX-1 and -2. Melamine exhibited noncompetitive inhibition of HRP (9.5±0.7mM, and LPO showed a mixed model of inhibition (14.5±4.7mM. The inhibition of HRP and LPO was confirmed using a chemiluminescent peroxidase assay. Melamine also exhibited COX-1 inhibition, but inhibition of COX-2 was not detected. Thus, our results demonstrate that melamine inhibits the activity of three heme peroxidases.

  10. Activation of lactoperoxidase by heme-linked protonation and heme-independent iodide binding. (United States)

    Toyama, Akira; Tominaga, Aya; Inoue, Tatsuo; Takeuchi, Hideo


    Lactoperoxidase (LPO), a mammalian secretory heme peroxidase, catalyzes the oxidation of thiocyanate by hydrogen peroxide to produce hypothiocyanate, an antibacterial agent. Although LPO is known to be activated at acidic pH and in the presence of iodide, the structural basis of the activation is not well understood. We have examined the effects of pH and iodide concentration on the catalytic activity and the structure of LPO. Electrochemical and colorimetric assays have shown that the catalytic activity is maximized at pH 4.5. The heme Soret absorption band exhibits a small red-shift at pH 5.0 upon acidification, which is ascribable to a structural transition from a neutral to an acidic form. Resonance Raman spectra suggest that the heme porphyrin core is slightly contracted and the Fe-His bond is strengthened in the acidic form compared to the neutral form. The structural change of LPO upon activation at acidic pH is similar to that observed for myeloperoxidase, another mammalian heme peroxidase, upon activation at neutral pH. Binding of iodide enhances the catalytic activity of LPO without affecting either the optimum pH of activity or the heme structure, implying that the iodide binding occurs at a protein site away from the heme-linked protonation site.

  11. Malaria and human red blood cells. (United States)

    Mohandas, Narla; An, Xiuli


    Invasion by the malaria parasite, Plasmodium falciparum, brings about extensive changes in the host red cells. These include loss of the normal discoid shape, increased rigidity of the membrane, elevated permeability to a wide variety of ionic and other species and increased adhesiveness, most notably to endothelial surfaces. These effects facilitate survival of the parasite within the host cell and tend to increase the virulence of disease that includes cerebral malaria and anemia. Numerous proteins secreted by the internalized parasite and interacting with red cell membrane proteins are responsible for the changes occurring to the host cell. Anemia, a serious clinical manifestation of malaria, is due to increased destruction of both infected and uninfected red cells due to membrane alterations, as well as ineffective erythropoiesis. There is very good evidence that various red cell disorders including hemoglobinopathies and hereditary ovalocytosis decrease the virulence of disease following parasite infection. A number of mechanism(s) are likely responsible for the protective effect of various red cell abnormalities including decreased invasion, impaired intraerythrocytic development of the parasites and altered interaction between exported parasite proteins and the red cell membrane skeleton.

  12. Lessons from bloodless worms: heme homeostasis in C. elegans. (United States)

    Sinclair, Jason; Hamza, Iqbal


    Heme is an essential cofactor for proteins involved in diverse biological processes such as oxygen transport, electron transport, and microRNA processing. Free heme is hydrophobic and cytotoxic, implying that specific trafficking pathways must exist for the delivery of heme to target hemoproteins which reside in various subcellular locales. Although heme biosynthesis and catabolism have been well characterized, the pathways for trafficking heme within and between cells remain poorly understood. Caenorhabditis elegans serves as a unique animal model for uncovering these pathways because, unlike vertebrates, the worm lacks enzymes to synthesize heme and therefore is crucially dependent on dietary heme for sustenance. Using C. elegans as a genetic animal model, several novel heme trafficking molecules have been identified. Importantly, these proteins have corresponding homologs in vertebrates underscoring the power of using C. elegans, a bloodless worm, in elucidating pathways in heme homeostasis and hematology in humans. Since iron deficiency and anemia are often exacerbated by parasites such as helminths and protozoa which also rely on host heme for survival, C. elegans will be an ideal model to identify anti-parasitic drugs that target heme transport pathways unique to the parasite.

  13. Malaria and Vascular Endothelium

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Aristóteles Comte Filho de, E-mail: [Universidade Federal do Amazonas, Manaus, AM (Brazil); Lacerda, Marcus Vinícius Guimarães de [Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, AM (Brazil); Okoshi, Katashi; Okoshi, Marina Politi [Faculdade de Medicina de Botucatu (Unesp), Botucatu, SP (Brazil)


    Involvement of the cardiovascular system in patients with infectious and parasitic diseases can result from both intrinsic mechanisms of the disease and drug intervention. Malaria is an example, considering that the endothelial injury by Plasmodium-infected erythrocytes can cause circulatory disorders. This is a literature review aimed at discussing the relationship between malaria and endothelial impairment, especially its effects on the cardiovascular system. We discuss the implications of endothelial aggression and the interdisciplinarity that should guide the malaria patient care, whose acute infection can contribute to precipitate or aggravate a preexisting heart disease.

  14. Malaria prevention in travelers. (United States)

    Genton, Blaise; D'Acremont, Valérie


    A common approach to malaria prevention is to follow the "A, B, C, D" rule: Awareness of risk, Bite avoidance, Compliance with chemoprophylaxis, and prompt Diagnosis in case of fever. The risk of acquiring malaria depends on the length and intensity of exposure; the risk of developing severe disease is primarily determined by the health status of the traveler. These parameters need to be assessed before recommending chemoprophylaxis and/or stand-by emergency treatment. This review discusses the different strategies and drug options available for the prevention of malaria during and post travel.

  15. Bioinformatics approaches to malaria

    DEFF Research Database (Denmark)

    Hansen, Daniel Aaen

    Malaria is a life threatening disease found in tropical and subtropical regions of the world. Each year it kills 781 000 individuals; most of them are children under the age of five in sub-Saharan Africa. The most severe form of malaria in humans is caused by the parasite Plasmodium falciparum......, which is the subject of the first part of this thesis. The PfEMP1 protein which is encoded by the highly variablevargene family is important in the pathogenesis and immune evasion of malaria parasites. We analyzed and classified these genes based on the upstream sequence in seven......Plasmodium falciparumclones. We show that the amount of nucleotide diversity is just as big within each clone as it is between the clones. DNA methylation is an important epigenetic mark in many eukaryotic species. We are studying DNA methylation in the malaria parasitePlasmodium falciparum. The work is still in progress...

  16. Malaria in Pregnancy


    Apuzzio, Joseph J.; Abdulla Al-Khan; Jesus R. Alvarez


    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be aler...

  17. Malaria in pregnancy.


    Jesus R. Alvarez; Al-Khan, Abdulla; Apuzzio, Joseph J.


    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be aler...

  18. Malaria in pregnancy. (United States)

    Alvarez, Jesus R; Al-Khan, Abdulla; Apuzzio, Joseph J


    Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be alert of the disease and its effects on pregnancy.

  19. Malaria in Pregnancy

    Directory of Open Access Journals (Sweden)

    Jesus R. Alvarez


    Full Text Available Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be alert of the disease and its effects on pregnancy.

  20. Vasoespasmo cerebral

    Directory of Open Access Journals (Sweden)

    Antonio A. F. de Salles


    Full Text Available Vasoespasmo cerebral ocorre em patologias como enxaqueca, hemorragia subaracnóidea, trauma de crânio, após isquemia e/ou hipoxia. A fisiopatologia do vasoespasmo cerebral nestas patologias não está completamente desvendada. Neste artigo são analisados os fatores neuroquímicos e morfológicos responsáveis pelo controle circulatório cerebral. As alterações circulatórias que seguem a hemorragia subaracnóidea são utilizadas como exemplo. Conclui-se que fatores bioquímicos, fisiológicos e morfológicos são responsáveis pelas manifestações vasculares que ocorrem após a hemorragia subaracnóidea. Alternativas de tratamento do vasoespasmo cerebral são discutidas.

  1. Cerebral Paragonimiasis. (United States)

    Miyazaki, I


    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.

  2. Phagocytic uptake of oxidized heme polymer is highly cytotoxic to macrophages.

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    Rohitas Deshmukh

    Full Text Available Apoptosis in macrophages is responsible for immune-depression and pathological effects during malaria. Phagocytosis of PRBC causes induction of apoptosis in macrophages through release of cytosolic factors from infected cells. Heme polymer or β-hematin causes dose-dependent death of macrophages with LC50 of 132 µg/ml and 182 µg/ml respectively. The toxicity of hemin or heme polymer was amplified several folds in the presence of non-toxic concentration of methemoglobin. β-hematin uptake in macrophage through phagocytosis is crucial for enhanced toxicological effects in the presence of methemoglobin. Higher accumulation of β-hematin is observed in macrophages treated with β-hematin along with methemoglobin. Light and scanning electron microscopic observations further confirm accumulation of β-hematin with cellular toxicity. Toxicological potentiation of pro-oxidant molecules toward macrophages depends on generation of H2O2 and independent to release of free iron from pro-oxidant molecules. Methemoglobin oxidizes β-hematin to form oxidized β-hematin (βH* through single electron transfer mechanism. Pre-treatment of reaction mixture with spin-trap Phenyl-N-t-butyl-nitrone dose-dependently reverses the β-hematin toxicity, indicates crucial role of βH* generation with the toxicological potentiation. Acridine orange/ethidium bromide staining and DNA fragmentation analysis indicate that macrophage follows an oxidative stress dependent apoptotic pathway to cause death. In summary, current work highlights mutual co-operation between methemoglobin and different pro-oxidant molecules to enhance toxicity towards macrophages. Hence, methemoglobin peroxidase activity can be probed for subduing cellular toxicity of pro-oxidant molecules and it may in-turn make up for host immune response against the malaria parasite.

  3. Malaria induced acute renal failure: A single center experience

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    Kanodia K


    Full Text Available Malaria has protean clinical manifestations and renal complications, particularly acute renal failure that could be life threatening. To evaluate the incidence, clinical profile, out-come and predictors of mortality in patients with malarial acute renal failure, we retrospectively studied the last two years records of malaria induced acute renal failure in patients with peripheral smear positive for malarial parasites. One hundred (10.4% (63 males, 37 females malaria induced acute renal failure amongst 958 cases of acute renal failure were evaluated. Plasmodium (P. falciparum was reported in 85%, P. vivax in 2%, and both in 13% patients. The mean serum creatinine was 9.2 ± 4.2 mg%, and oligo/anuria was present in 82%; 78% of the patients required hemodialysis. Sixty four percent of the patients recovered completely, 10% incompletely, and 5% developed chronic kidney failure; mortality occurred in 21% of the patients. Low hemoglobin, oligo/anuria on admission, hyperbilirubinemia, cerebral malaria, disseminated intravascular coa-gulation, and high serum creatinine were the main predictors of mortality. We conclude that ma-laria is associated with acute renal failure, which occurs most commonly in plasmodium falci-parum infected patients. Early diagnosis and prompt dialysis with supportive management can reduce morality and enhance recovery of renal function.

  4. Complement receptor 1 and the molecular pathogenesis of malaria

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    Gandhi Monika


    Full Text Available Malaria is a pathogenic infection caused by protozoa of the genus plasmodium. It is mainly confined to sub-Saharan Africa, Asia and South America. This disease claims the life of over 1.5 to 2.7 million people per year. Owing to such a high incidence of malarial infections, there is an urgent need for the development of suitable vaccines. For the development of ideal vaccines, it is essential to understand the molecular mechanisms of malarial pathogenesis and the factors that lead to malaria infection. Genetic factors have been proposed to play an important role in malarial pathogenesis. Complement receptor 1 (CR1 is an important host red blood cell protein involved in interaction with malarial parasite. Various polymorphic forms of CR1 have been found to be involved in conferring protection or increasing susceptibility to malaria infections. Low-density allele (L of CR1 gave contradictory results in different set of studies. In addition, Knops polymorphic forms Sl (a + and McC (a have been found to contribute more towards the occurrence of cerebral malaria in malaria endemic regions compared to individuals with Sl (a - / McC (a/b genotype. This article reviews the research currently going on in this area and throws light on as yet unresolved mysteries of the role of CR1 in malarial pathogenesis.

  5. Prediction of outcome in adults with severe falciparum malaria: a new scoring system

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    Mishra Rajalaxmi


    Full Text Available Abstract Background Mortality of falciparum malaria is related to the presence of severe complications. However, no scoring system is available to predict outcome of these patients. The aim of this paper was to devise a simple and reliable malaria prognosis score (MPS to predict the outcome of adults with severe malaria. Methods All slide-positive severe falciparum malaria patients admitted to Ispat General Hospital were studied. Eight clinical parameters that may potentially differentiate or influence the outcome were identified to predict recovery or death Results Of 248 severe malaria cases, 35 died. There were 212 adults (34 deaths and 36 children (one death. The malaria score for adults was (MSA = 1(severe anaemia + 2 (acute renal failure + 3(Respiratory distress +4 (cerebral malaria. The MSA ranges from 0 to 10. The mortality was 2% for MSA 0 – 2; 10% for MSA 3–4, 40% for MSA 5–6 and 90% for MSA 7 or more. The sensitivity is 89.9% and positive predictive value is 94.1% when 5 is taken as the cut off value. Conclusion MSA is a simple and sensitive predictor. It can be administered rapidly and repeatedly to prognosticate the outcome of severe malaria in adults. It can help the treating doctor to assess the patient as well as to communicate to the relatives of the patients about prognosis. The score needs revalidation in other geographical areas.

  6. UK malaria treatment guidelines. (United States)

    Lalloo, David G; Shingadia, Delane; Pasvol, Geoffrey; Chiodini, Peter L; Whitty, Christopher J; Beeching, Nicholas J; Hill, David R; Warrell, David A; Bannister, Barbara A


    Malaria is the tropical disease most commonly imported into the UK, with 1500-2000 cases reported each year, and 10-20 deaths. Approximately three-quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other two species of Plasmodium: Plasmodium ovale or Plasmodium malariae. Mixed infections with more than 1 species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until 3 blood specimens have been examined by an experienced microscopist. There are no typical clinical features of malaria, even fever is not invariably present. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites; P. falciparum malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens or enzymes, although RDTs for other Plasmodium species are not as reliable. The treatment of choice for non-falciparum malaria is a 3-day course of oral chloroquine, to which only a limited proportion of P. vivax strains have gained resistance. Dormant parasites (hypnozoites) persist in the liver after treatment of P. vivax or P. ovale infection: the only currently effective drug for eradication of hypnozoites is primaquine. This must be avoided or given with caution under expert supervision in patients with glucose-6-phosphate dehydrogenase deficiency (G6PD), in whom it may cause severe haemolysis. Uncomplicated P. falciparum malaria can be treated orally with quinine, atovaquone plus proguanil (Malarone) or co-artemether (Riamet

  7. To report a case of unilateral proliferative retinopathy following noncerebral malaria with Plasmodium falciparum in Southern India

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    Aditya Verma


    Full Text Available The retinopathy in association with malaria fever described so far includes retinal hemorrhages, vessel changes, retinal discoloration/whitening and papilledema. Malaria retinopathy has been mostly described in severe cases, associated with Plasmodium falciparum, correlating the patho-physiology of retinal and cerebral manifestations. We report an unusual case of proliferative retinopathy as a manifestation of malaria fever, caused by P. falciparum with no cerebral involvement. The patient had features of unilateral retinal vascular occlusion with proliferative changes and vitreous hemorrhage. To the best of our knowledge, such a case has never been reported so far in the literature. This report highlights the possible occurrence of severe proliferative changes associated with malaria fever, which if diagnosed early can prevent possible blindness.

  8. Spontaneous Subdural Empyema Following a High-Parasitemia Falciparum Infection in a 58-Year-Old Female From a Malaria-Endemic Region

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    Pedro Pallangyo MD, MPH


    Full Text Available Malaria remains a significant public health problem of the tropical world. Falciparum malaria is most prevalent in the sub-Saharan African region, which harbors about 90% of all malaria cases and fatalities globally. Infection by the falciparum species often manifests with a spectrum of multi-organ complications (eg, cerebral malaria, some of which are life-threatening. Spontaneous subdural empyema is a very rare complication of cerebral malaria that portends a very poor prognosis unless diagnosed and treated promptly. We report a case of spontaneous subdural empyema in a 58-year-old woman from Tanzania who presented with high-grade fever, decreased urine output, and altered sensorium.

  9. Apicoplast Biosynthetic Pathways as Possible Targetsfor Combination Therapy of Malaria

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    Solomon Tesfaye; Bhanu Prakash; Prati Pal Singh


    The emergence of malaria parasite strains resistant to practically all the antimalarial drugs in clinical use is now making itnecessary to discover and develop both new antimalarial drugs and treatments. Recent advances in molecular techniques along withthe availability of genome sequence ofPlasmodiumfalciparum may provide a wide range of novel targets in metabolic pathways likeisoprenoid biosynthesis, fatty acid biosynthesis and heme biosynthesis in the apicoplast of Plasmodiurn. On the other hand, thecombination therapy approach (currently used to retard the selection of parasite strains resistant to individual components of acombination of drugs) has proved to be a success in the combination of sulphadoxine and pyrimethamine, which targets two differentsteps in the folate pathway of malaria parasite. However, after the success of this therapeutic combination, the efficacy of othercombinations of drugs which target different enzymes in a particular metabolic pathway has, apparently, not been reported. Therefore,herein, we review various drug targets so far discovered in apicoplast-related anabolic pathways, especially, with a sharper focus onthe possibility to target more than one enzyme at a time in a particular metabolic pathway of malaria parasites.

  10. Monkey malaria kills four humans. (United States)

    Galinski, Mary R; Barnwell, John W


    Four human deaths caused by Plasmodium knowlesi, a simian malaria species, are stimulating a surge of public health interest and clinical vigilance in vulnerable areas of Southeast Asia. We, and other colleagues, emphasize that these cases, identified in Malaysia, are a clear warning that health facilities and clinicians must rethink the diagnosis and treatment of malaria cases presumed to be caused by a less virulent human malaria species, Plasmodium malariae.

  11. Role of Heme and Heme-Proteins in Trypanosomatid Essential Metabolic Pathways

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    Karina E. J. Tripodi


    Full Text Available Around the world, trypanosomatids are known for being etiological agents of several highly disabling and often fatal diseases like Chagas disease (Trypanosoma cruzi, leishmaniasis (Leishmania spp., and African trypanosomiasis (Trypanosoma brucei. Throughout their life cycle, they must cope with diverse environmental conditions, and the mechanisms involved in these processes are crucial for their survival. In this review, we describe the role of heme in several essential metabolic pathways of these protozoans. Notwithstanding trypanosomatids lack of the complete heme biosynthetic pathway, we focus our discussion in the metabolic role played for important heme-proteins, like cytochromes. Although several genes for different types of cytochromes, involved in mitochondrial respiration, polyunsaturated fatty acid metabolism, and sterol biosynthesis, are annotated at the Tritryp Genome Project, the encoded proteins have not yet been deeply studied. We pointed our attention into relevant aspects of these protein functions that are amenable to be considered for rational design of trypanocidal agents.

  12. Isocyanides Inhibit Human Heme Oxygenases at the Verdoheme Stage†


    Evans, John P.; Kandel, Sylvie; Ortiz de Montellano, Paul R.


    Heme oxygenases (HO) catalyze the oxidative cleavage of heme to generate biliverdin, CO, and free iron. In humans, heme oxygenase-1 (hHO-1) is overexpressed in tumor tissues, where it helps to protect cancer cells from anticancer agents, while HOs in fungal pathogens, such as Candida albicans, function as the primary means of iron acquisition. Thus, HO can be considered a potential therapeutic target for certain diseases. In this study, we have examined the equilibrium binding of three isocya...

  13. Holo- And Apo- Structures of Bacterial Periplasmic Heme Binding Proteins

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    Ho, W.W.; Li, H.; Eakanunkul, S.; Tong, Y.; Wilks, A.; Guo, M.; Poulos, T.L.


    An essential component of heme transport in Gram-negative bacterial pathogens is the periplasmic protein that shuttles heme between outer and inner membranes. We have solved the first crystal structures of two such proteins, ShuT from Shigella dysenteriae and PhuT from Pseudomonas aeruginosa. Both share a common architecture typical of Class III periplasmic binding proteins. The heme binds in a narrow cleft between the N- and C-terminal binding domains and is coordinated by a Tyr residue. A comparison of the heme-free (apo) and -bound (holo) structures indicates little change in structure other than minor alterations in the heme pocket and movement of the Tyr heme ligand from an 'in' position where it can coordinate the heme iron to an 'out' orientation where it points away from the heme pocket. The detailed architecture of the heme pocket is quite different in ShuT and PhuT. Although Arg{sup 228} in PhuT H-bonds with a heme propionate, in ShuT a peptide loop partially takes up the space occupied by Arg{sup 228}, and there is no Lys or Arg H-bonding with the heme propionates. A comparison of PhuT/ShuT with the vitamin B{sub 12}-binding protein BtuF and the hydroxamic-type siderophore-binding protein FhuD, the only two other structurally characterized Class III periplasmic binding proteins, demonstrates that PhuT/ShuT more closely resembles BtuF, which reflects the closer similarity in ligands, heme and B{sub 12}, compared with ligands for FhuD, a peptide siderophore.

  14. Towards A Malaria Vaccine?

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    B S GARG


    Full Text Available The last few years have seen a marked change in the understanding of malaria mmunology.We have very little knowledge on immunity of Malaria based on experiments in humanbeings due to ethical reasons. Whatsoever our knowledge exists at present is based onexperimentas in mice and monkey. However it is clear that it is sporzoite or merozoitewhich is directly exposed to our immune system in the life cycle of Malaria parasite. On thebasis of human experiments we can draw inference that immunity to malaria is species.specific (on cross immunity, stage specific and strain specific as well acquired in the response to surface antigen and relapsed antigen although the parasite also demonstrates escape machanism to immune system.So the host system kills or elimi nate the parasite by means of (a Antbody to extracell~ular form of parasite with the help of mechanism of Block invasion, Agglutination or opsonization and/or (b Cellular machanism-either by phago-cytosis of parasite or by antibody dependent cellular cytotoxicity ABCC (? or by effects of mediators like tumor necrosis fJ.ctor (TNF in cerebaral malaria or crisis forming factor as found in sudan or by possible role of lysis mechanism.However, inspite of all these theories the parasite has been able to invade the immunesystem by virtue of its intracellular development stage specificity, sequestration in capillaries and also by its unusual characteristics of antigenic diversity and antigenic variation.

  15. Oxidative Stress Is Related to the Deleterious Effects of Heme Oxygenase-1 in an In Vivo Neuroinflammatory Rat Model

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    Claire Tronel


    Full Text Available Heme oxygenase-1 (HO-1 induction is associated with beneficial or deleterious effects depending on the experimental conditions adopted and the neurodegenerative rodent models used. The present study aimed first to evaluate the effects of cerebral HO-1 induction in an in vivo rat model of neuroinflammation by intrastriatal injection of quinolinic acid (QA and secondly to explore the role played by reactive oxygen species (ROS and free iron (Fe2+ derived from heme catabolism promoted by HO-1. Chronic I.P. treatment with the HO-1 inductor and substrate hemin was responsible for a significant dose-related increase of cerebral HO-1 production. Brain tissue loss, microglial activation, and neuronal death were significantly higher in rats receiving QA plus hemin (H-QA versus QA and controls. Significant increase of ROS production in H-QA rat brain was inhibited by the specific HO-1 inhibitor ZnPP which supports the idea that ROS level augmentation in hemin-treated animals is a direct consequence of HO-1 induction. The cerebral tissue loss and ROS level in hemin-treated rats receiving the iron chelator deferoxamine were significantly decreased, demonstrating the involvement of Fe2+in brain ROS production. Therefore, the deleterious effects of HO-1 expression in this in vivo neuroinflammatory model were linked to a hyperproduction of ROS, itself promoted by free iron liberation.

  16. Mechanisms of peroxynitrite interactions with heme proteins. (United States)

    Su, Jia; Groves, John T


    Oxygenated heme proteins are known to react rapidly with nitric oxide (NO) to produce peroxynitrite (PN) at the heme site. This process could lead either to attenuation of the effects of NO or to nitrosative protein damage. PN is a powerful nitrating and oxidizing agent that has been implicated in a variety of cell injuries. Accordingly, it is important to delineate the nature and variety of reaction mechanisms of PN interactions with heme proteins. In this Forum, we survey the range of reactions of PN with heme proteins, with particular attention to myoglobin and cytochrome c. While these two proteins are textbook paradigms for oxygen binding and electron transfer, respectively, both have recently been shown to have other important functions that involve NO and PN. We have recently described direct evidence that ferrylmyolgobin (ferrylMb) and nitrogen dioxide (NO(2)) are both produced during the reaction of PN and metmyolgobin (metMb) (Su, J.; Groves, J. T. J. Am. Chem. Soc. 2009, 131, 12979-12988). Kinetic evidence indicates that these products evolve from the initial formation of a caged radical intermediate [Fe(IV) horizontal lineO.NO(2)]. This caged pair reacts mainly via internal return with a rate constant k(r) to form metMb and nitrate in an oxygen-rebound scenario. Detectable amounts of ferrylMb are observed by stopped-flow spectrophotometry, appearing at a rate consistent with the rate, k(obs), of heme-mediated PN decomposition. Freely diffusing NO(2), which is liberated concomitantly from the radical pair (k(e)), preferentially nitrates myoglobin Tyr103 and added fluorescein. For cytochrome c, Raman spectroscopy has revealed that a substantial fraction of cytochrome c converts to a beta-sheet structure, at the expense of turns and helices at low pH (Balakrishnan, G.; Hu, Y.; Oyerinde, O. F.; Su, J.; Groves, J. T.; Spiro, T. G. J. Am. Chem. Soc., 2007, 129, 504-505). It is proposed that a short beta-sheet segment, comprising residues 37-39 and 58

  17. Vasoespasmo cerebral



    Vasoespasmo cerebral ocorre em patologias como enxaqueca, hemorragia subaracnóidea, trauma de crânio, após isquemia e/ou hipoxia. A fisiopatologia do vasoespasmo cerebral nestas patologias não está completamente desvendada. Neste artigo são analisados os fatores neuroquímicos e morfológicos responsáveis pelo controle circulatório cerebral. As alterações circulatórias que seguem a hemorragia subaracnóidea são utilizadas como exemplo. Conclui-se que fatores bioquímicos, fisiológicos e morfológi...

  18. Predictors of anti-convulsant treatment failure in children presenting with malaria and prolonged seizures in Kampala, Uganda

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    Byarugaba Justus


    Full Text Available Abstract Background In endemic areas, falciparum malaria remains the leading cause of seizures in children presenting to emergency departments. In addition, seizures in malaria have been shown to increase morbidity and mortality in these patients. The management of seizures in malaria is sometimes complicated by the refractory nature of these seizures to readily available anti-convulsants. The objective of this study was to determine predictors of anti-convulsant treatment failure and seizure recurrence after initial control among children with malaria. Methods In a previous study, the efficacy and safety of buccal midazolam was compared to that of rectal diazepam in the treatment of prolonged seizures in children aged three months to 12 years in Kampala, Uganda. For this study, predictive models were used to determine risk factors for anti-convulsant treatment failure and seizure recurrence among the 221 of these children with malaria. Results Using predictive models, focal seizures (OR 3.21; 95% CI 1.42–7.25, p = 0.005, cerebral malaria (OR 2.43; 95% CI 1.20–4.91, p = 0.01 and a blood sugar ≥200 mg/dl at presentation (OR 2.84; 95% CI 1.11–7.20, p = 0.02 were independent predictors of treatment failure (seizure persistence beyond 10 minutes or recurrence within one hour of treatment. Predictors of seizure recurrence included: 1 cerebral malaria (HR 3.32; 95% CI 1.94–5.66, p Conclusion Specific predictors, including cerebral malaria, can identify patients with malaria at risk of anti-convulsant treatment failure and seizure recurrence.

  19. [Study on malaria vectors in malaria endemic areas of Tibet autonomous region]. (United States)

    Wu, Song; Huang, Fang; Zhou, Shui-Sen; Tang, Lin-Hua


    The malaria situation in Tibet has been in an active status and the malaria incidence reached the second in China in 2010. Malaria vector prevention and control is one of the important methods for malaria control, while the malaria vectors are still unknown in Tibet. The author summarized the past researches on malaria vectors in Tibet, so as to provide the evidence for improving malaria control investigation in malaria endemic areas of Tibet, with hopes to provide useful vector message for other researcher.

  20. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains

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    Jespersen, Jakob S.; Wang, Christian W.; Mkumbaye, Sixbert I.;


    Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human...... endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR-binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full......-length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support...

  1. Identification of a Platelet Membrane Glycoprotein as a Falciparum Malaria Sequestration Receptor (United States)

    Ockenhouse, Christian F.; Tandon, Narendra N.; Magowan, Cathleen; Jamieson, G. A.; Chulay, Jeffrey D.


    Infections with the human malaria parasite Plasmodium falciparum are characterized by sequestration of erythrocytes infected with mature forms of the parasite. Sequestration of infected erythrocytes appears to be critical for survival of the parasite and to mediate immunopathological abnormalities in severe malaria. A leukocyte differentiation antigen (CD36) was previously suggested to have a role in sequestration of malaria-infected erythrocytes. CD36 was purified from platelets, where it is known as GPIV, and was shown to be a receptor for binding of infected erythrocytes. Infected erythrocytes adhered to CD36 immobilized on plastic; purified CD36 exhibited saturable, specific binding to infected erythrocytes; and purified CD36 or antibodies to CD36 inhibited and reversed binding of infected erythrocytes to cultured endothelial cells and melanoma cells in vitro. The portion of the CD36 molecule that reverses cytoadherence may be useful therapeutically for rapid reversal of sequestration in cerebral malaria.


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    Begoña Monge-Maillo


    Full Text Available The proportion of imported malaria cases due to immigrants in Europe has increased during the lasts decades, being the higher rates for those settled immigrants who travel to visit friends and relatives (VFRs at their country of origin. Cases are mainly due to P. falciparum and Sub-Saharan Africa is the most common origin. Clinically, malaria in immigrants is characterized by a mild clinical presentation with even asymptomatic o delayed malaria cases and low parasitemic level. These characteristics may be explained by a semi-immunity acquired after long periods of time exposed to stable transmission of malaria. Malaria cases among immigrants, even those asymptomatic patients with sub-microscopic parasitemia, could increase the risk of transmission and reintroduction of malaria in certain areas with the adequate vectors and climate conditions. Moreover imported malaria cases by immigrants can also play an important role in the non-vectorial transmission out of endemic area, by blood transfusions, organ transplantation or congenital or occupational exposures. Probably, out of endemic areas, screening of malaria among recent arrived immigrants coming from malaria endemic countries should be performed. These aim to reduce the risk of clinical malaria in the individual as well as to prevent autochthonous transmission of malaria in areas where it had been eradicated.

  3. Research toward Malaria Vaccines (United States)

    Miller, Louis H.; Howard, Russell J.; Carter, Richard; Good, Michael F.; Nussenzweig, Victor; Nussenzweig, Ruth S.


    Malaria exacts a toll of disease to people in the Tropics that seems incomprehensible to those only familiar with medicine and human health in the developed world. The methods of molecular biology, immunology, and cell biology are now being used to develop an antimalarial vaccine. The Plasmodium parasites that cause malaria have many stages in their life cycle. Each stage is antigenically distinct and potentially could be interrupted by different vaccines. However, achieving complete protection by vaccination may require a better understanding of the complexities of B- and T-cell priming in natural infections and the development of an appropriate adjuvant for use in humans.

  4. Heme Recognition By a Staphylococcus Aureus IsdE

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    Grigg, J.C.; Vermeiren, C.L.; Heinrichs, D.E.; Murphy, M.E.P.


    Staphylococcus aureus is a Gram-positive bacterial pathogen and a leading cause of hospital acquired infections. Because the free iron concentration in the human body is too low to support growth, S. aureus must acquire iron from host sources. Heme iron is the most prevalent iron reservoir in the human body and a predominant source of iron for S. aureus. The iron-regulated surface determinant (Isd) system removes heme from host heme proteins and transfers it to IsdE, the cognate substrate-binding lipoprotein of an ATP-binding cassette transporter, for import and subsequent degradation. Herein, we report the crystal structure of the soluble portion of the IsdE lipoprotein in complex with heme. The structure reveals a bi-lobed topology formed by an N- and C-terminal domain bridged by a single {alpha}-helix. The structure places IsdE as a member of the helical backbone metal receptor superfamily. A six-coordinate heme molecule is bound in the groove established at the domain interface, and the heme iron is coordinated in a novel fashion for heme transporters by Met{sup 78} and His{sup 229}. Both heme propionate groups are secured by H-bonds to IsdE main chain and side chain groups. Of these residues, His{sup 299} is essential for IsdE-mediated heme uptake by S. aureus when growth on heme as a sole iron source is measured. Multiple sequence alignments of homologues from several other Gram-positive bacteria, including the human pathogens pyogenes, Bacillus anthracis, and Listeria monocytogenes, suggest that these other systems function equivalently to S. aureus IsdE with respect to heme binding and transport.

  5. Hemoglobinopathies: slicing the Gordian knot of Plasmodium falciparum malaria pathogenesis. (United States)

    Taylor, Steve M; Cerami, Carla; Fairhurst, Rick M


    Plasmodium falciparum malaria kills over 500,000 children every year and has been a scourge of humans for millennia. Owing to the co-evolution of humans and P. falciparum parasites, the human genome is imprinted with polymorphisms that not only confer innate resistance to falciparum malaria, but also cause hemoglobinopathies. These genetic traits--including hemoglobin S (HbS), hemoglobin C (HbC), and α-thalassemia--are the most common monogenic human disorders and can confer remarkable degrees of protection from severe, life-threatening falciparum malaria in African children: the risk is reduced 70% by homozygous HbC and 90% by heterozygous HbS (sickle-cell trait). Importantly, this protection is principally present for severe disease and largely absent for P. falciparum infection, suggesting that these hemoglobinopathies specifically neutralize the parasite's in vivo mechanisms of pathogenesis. These hemoglobin variants thus represent a "natural experiment" to identify the cellular and molecular mechanisms by which P. falciparum produces clinical morbidity, which remain partially obscured due to the complexity of interactions between this parasite and its human host. Multiple lines of evidence support a restriction of parasite growth by various hemoglobinopathies, and recent data suggest this phenomenon may result from host microRNA interference with parasite metabolism. Multiple hemoglobinopathies mitigate the pathogenic potential of parasites by interfering with the export of P. falciparum erythrocyte membrane protein 1 (PfEMP1) to the surface of the host red blood cell. Few studies have investigated their effects upon the activation of the innate and adaptive immune systems, although recent murine studies suggest a role for heme oxygenase-1 in protection. Ultimately, the identification of mechanisms of protection and pathogenesis can inform future therapeutics and preventive measures. Hemoglobinopathies slice the "Gordian knot" of host and parasite

  6. Hemoglobinopathies: slicing the Gordian knot of Plasmodium falciparum malaria pathogenesis.

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    Steve M Taylor

    Full Text Available Plasmodium falciparum malaria kills over 500,000 children every year and has been a scourge of humans for millennia. Owing to the co-evolution of humans and P. falciparum parasites, the human genome is imprinted with polymorphisms that not only confer innate resistance to falciparum malaria, but also cause hemoglobinopathies. These genetic traits--including hemoglobin S (HbS, hemoglobin C (HbC, and α-thalassemia--are the most common monogenic human disorders and can confer remarkable degrees of protection from severe, life-threatening falciparum malaria in African children: the risk is reduced 70% by homozygous HbC and 90% by heterozygous HbS (sickle-cell trait. Importantly, this protection is principally present for severe disease and largely absent for P. falciparum infection, suggesting that these hemoglobinopathies specifically neutralize the parasite's in vivo mechanisms of pathogenesis. These hemoglobin variants thus represent a "natural experiment" to identify the cellular and molecular mechanisms by which P. falciparum produces clinical morbidity, which remain partially obscured due to the complexity of interactions between this parasite and its human host. Multiple lines of evidence support a restriction of parasite growth by various hemoglobinopathies, and recent data suggest this phenomenon may result from host microRNA interference with parasite metabolism. Multiple hemoglobinopathies mitigate the pathogenic potential of parasites by interfering with the export of P. falciparum erythrocyte membrane protein 1 (PfEMP1 to the surface of the host red blood cell. Few studies have investigated their effects upon the activation of the innate and adaptive immune systems, although recent murine studies suggest a role for heme oxygenase-1 in protection. Ultimately, the identification of mechanisms of protection and pathogenesis can inform future therapeutics and preventive measures. Hemoglobinopathies slice the "Gordian knot" of host and

  7. Determining utility values related to malaria and malaria chemoprophylaxis

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    Coyle Doug


    Full Text Available Abstract Background Chemoprophylaxis for travellers' malaria is problematic. Decision modeling may help determine optimal prevention strategies for travellers' malaria. Such models can fully assess effect of drug use and disease on quality of life, and help travellers make informed values based decisions. Such models require utility values reflecting societal preferences over different health states of relevance. To date, there are no published utility values relating to clinical malaria or chemoprophylaxis adverse events. Methods Utility estimates for health states related to falciparum malaria, sequelae and drug-related adverse events were obtained using a self-administered visual analogue scale in 20 individuals. Utility values for health states related to clinical malaria were obtained from a survey of 11 malaria experts questioned about length of hospital stay or equivalent disability with simple and severe travellers' malaria. Results The general public (potential travellers, were more tolerant of taking prophylaxis if associated with no or mild AEs and least tolerant of mild sequelae from malaria and severe drug related events. The rating value reported for taking no prophylaxis was quite variable. Tropical medicine specialists estimated a mean hospital stay 3.23 days (range 0.5-4.5 days for simple and 6.36 days (range 4.5 - 7 days for severe malaria. Conclusions This study provides a benchmark for important utility value estimates for modeling malaria and drug-related outcomes in non-immune travellers.

  8. Investigating the Pathogenesis of Severe Malaria: A Multidisciplinary and Cross-Geographical Approach. (United States)

    Wassmer, Samuel C; Taylor, Terrie E; Rathod, Pradipsinh K; Mishra, Saroj K; Mohanty, Sanjib; Arevalo-Herrera, Myriam; Duraisingh, Manoj T; Smith, Joseph D


    More than a century after the discovery of Plasmodium spp. parasites, the pathogenesis of severe malaria is still not well understood. The majority of malaria cases are caused by Plasmodium falciparum and Plasmodium vivax, which differ in virulence, red blood cell tropism, cytoadhesion of infected erythrocytes, and dormant liver hypnozoite stages. Cerebral malaria coma is one of the most severe manifestations of P. falciparum infection. Insights into its complex pathophysiology are emerging through a combination of autopsy, neuroimaging, parasite binding, and endothelial characterizations. Nevertheless, important questions remain regarding why some patients develop life-threatening conditions while the majority of P. falciparum-infected individuals do not, and why clinical presentations differ between children and adults. For P. vivax, there is renewed recognition of severe malaria, but an understanding of the factors influencing disease severity is limited and remains an important research topic. Shedding light on the underlying disease mechanisms will be necessary to implement effective diagnostic tools for identifying and classifying severe malaria syndromes and developing new therapeutic approaches for severe disease. This review highlights progress and outstanding questions in severe malaria pathophysiology and summarizes key areas of pathogenesis research within the International Centers of Excellence for Malaria Research program.

  9. The neutral lipid composition present in the digestive vacuole of Plasmodium falciparum concentrates heme and mediates β-hematin formation with an unusually low activation energy. (United States)

    Hoang, Anh N; Sandlin, Rebecca D; Omar, Aneesa; Egan, Timothy J; Wright, David W


    In eukaryotic cells, neutral lipids serve as major energy storage molecules; however, in Plasmodium falciparum, a parasite responsible for causing malaria in humans, neutral lipids may have other functions during the intraerythrocytic stage of the parasite life cycle. Specifically, experimental data suggest that neutral lipid structures behave as a catalyst for the crystallization of hemozoin, a detoxification byproduct of several blood-feeding organisms, including malaria parasites. Synthetic neutral lipid droplets (SNLDs) were produced by depositing a lipid blend solution comprised of mono- and diglycerides onto an aqueous surface. These lipid droplets are able to mediate the production of brown pigments that are morphologically and chemically identical to hemozoin. The partitioning of heme into these SNLDs was examined by employing Nile Red, a lipid specific dye. Soluble ferriprotoporphyrin IX was observed to spontaneously localize to the lipid droplets, partitioning in a pH-dependent manner with an estimated log P of 2.6. Interestingly, the pH profile of heme partitioning closely resembles that of β-hematin formation. Differential scanning calorimetry and kinetic studies demonstrated that the SNLDs provide a unique environment that promotes hemozoin formation. SNLD-mediated formation of the malaria pigment displayed an activation energy barrier lower than those of individual lipid components. In particular, lipid droplets composed of diglycerides displayed activation barriers lower than those composed of monoglycerides. This difference was attributed to the greater fluidity of these lipids. In conjunction with the known pattern of lipid body proliferation, it is suggested that neutral lipid structures within the digestive vacuole not only are the location of in vivo hemozoin formation but are also essential for the survival of the parasite by functioning as a kinetically competent and site specific mediator for heme detoxification.

  10. Severe imported malaria in an intensive care unit: a review of 59 cases

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    Santos Lurdes C


    Full Text Available Abstract Background In view of the close relationship of Portugal with African countries, particularly former Portuguese colonies, the diagnosis of malaria is not a rare thing. When a traveller returns ill from endemic areas, malaria should be the number one suspect. World Health Organization treatment guidelines recommend that adults with severe malaria should be admitted to an intensive care unit (ICU. Methods Severe cases of malaria in patients admitted to an ICU were reviewed retrospectively (1990-2011 and identification of variables associated with in-ICU mortality performed. Malaria prediction score (MPS, malaria score for adults (MSA, simplified acute physiology score (SAPSII and a score based on WHO's malaria severe criteria were applied. Statistical analysis was performed using StataV12. Results Fifty nine patients were included in the study, all but three were adults; 47 (79,6% were male; parasitaemia on admission, quantified in 48/59 (81.3% patients, was equal or greater than 2% in 47 of them (97.9%; the most common complications were thrombocytopaenia in 54 (91.5% patients, associated with disseminated intravascular coagulation (DIC in seven (11.8%, renal failure in 31 (52.5% patients, 18 of which (30.5% oliguric, shock in 29 (49.1% patients, liver dysfunction in 27 (45.7% patients, acidaemia in 23 (38.9% patients, cerebral dysfunction in 22 (37.2% patients, 11 of whom with unrousable coma, pulmonary oedema/ARDS in 22 (37.2% patients, hypoglycaemia in 18 (30.5% patients; 29 (49.1% patients presented five or more dysfunctions. The case fatality rate was 15.2%. Comparing the four scores, the SAPS II and the WHO score were the most sensitive to death prediction. In the univariate analysis, death was associated with the SAPS II score, cerebral malaria, acute renal and respiratory failure, DIC, spontaneous bleeding, acidosis and hypoglycaemia. Age, partial immunity to malaria, delay in malaria diagnosis and the level of parasitaemia were

  11. Heme oxygenase-1, oxidation, inflammation and atherosclerosis

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    Jesus A Araujo


    Full Text Available Atherosclerosis is an inflammatory process of the vascular wall characterized by the infiltration of lipids and inflammatory cells. Oxidative modifications of infiltrating low density lipoproteins and induction of oxidative stress play a major role in lipid retention in the vascular wall, uptake by macrophages and generation of foam cells, a hallmark of this disorder. The vasculature has a plethora of protective resources against oxidation and inflammation, many of them regulated by the Nrf2 transcription factor. Heme oxygenase-1 (HO-1 is a Nrf2-regulated gene that plays a critical role in the prevention of vascular inflammation. It is the inducible isoform of heme oxygenase, responsible for the oxidative cleavage of heme groups leading to the generation of biliverdin, carbon monoxide and release of ferrous iron. HO-1 has important antioxidant, antiinflammatory, antiapoptotic, antiproliferative and immunomodulatory effects in vascular cells, most of which play a significant role in the protection against atherogenesis. HO-1 may also be an important feature in macrophage differentiation and polarization to certain subtypes. The biological effects of HO-1 are largely attributable to its enzymatic activity, which can be conceived as a system with three arms of action, corresponding to its three enzymatic byproducts. HO-1 mediated vascular protection may be due to a combination of systemic and vascular local effects. It is usually expressed at low levels but can be highly upregulated in the presence of several proatherogenic stimuli. The HO-1 system is amenable for use in the development of new therapies, some of them currently under experimental and clinical trials. Interestingly, in contrast to the HO-1 antiatherogenic actions, the expression of its transcriptional regulator Nrf2 leads to proatherogenic effects instead. This article reviews the evidence that supports the antiatherogenic role of HO-1, potential pathways and mechanisms mediating

  12. Targeting heme oxygenase-1 in vascular disease. (United States)

    Durante, William


    Heme oxygenase-1 (HO-1) metabolizes heme to generate carbon monoxide (CO), biliverdin, and iron. Biliverdin is subsequently metabolized to bilirubin by biliverdin reductase. HO-1 has recently emerged as a promising therapeutic target in the treatment of vascular disease. Pharmacological induction or gene transfer of HO-1 ameliorates vascular dysfunction in animal models of atherosclerosis, post-angioplasty restenosis, vein graft stenosis, thrombosis, myocardial infarction, and hypertension, while inhibition of HO-1 activity or gene deletion exacerbates these disorders. The vasoprotection afforded by HO-1 is largely attributable to its end products: CO and the bile pigments, biliverdin and bilirubin. These end products exert potent anti-inflammatory, antioxidant, anti-apoptotic, and anti-thrombotic actions. In addition, CO and bile pigments act to preserve vascular homeostasis at sites of arterial injury by influencing the proliferation, migration, and adhesion of vascular smooth muscle cells, endothelial cells, endothelial progenitor cells, or leukocytes. Several strategies are currently being developed to target HO-1 in vascular disease. Pharmacological induction of HO-1 by heme derivatives, dietary antioxidants, or currently available drugs, is a promising near-term approach, while HO-1 gene delivery is a long-term therapeutic goal. Direct administration of CO via inhalation or through the use of CO-releasing molecules and/or CO-sensitizing agents provides an attractive alternative approach in targeting HO-1. Furthermore, delivery of bile pigments, either alone or in combination with CO, presents another avenue for protecting against vascular disease. Since HO-1 and its products are potentially toxic, a major challenge will be to devise clinically effective therapeutic modalities that target HO-1 without causing any adverse effects.

  13. Bone marrow: its contribution to heme catabolism. (United States)

    Mähönen, Y; Anttinen, M; Vuopio, P; Tenhunen, R


    Heme oxygenase (HO) and biliverdin reductase (BR), the two NADPH-dependent enzymes involved in the degradation of hemoglobin and its derivatives, were measured in bone marrow aspirates from 5 hematologically normal persons, 4 patients with chronic leucemia (CL), 11 patients with acute leucemia (AL), 8 patients with refractory sideroblastic anemia (RA), 7 patients with iron-deficiency anemia (IA), 5 patients with hemolytic anemia (HA), and 7 patients with secondary anemia (SA) to determine the enzymatic capacity of the bone marrow in different hematologic disorders for heme catabolism. HO activity in the bone marrow of normal persons was 0.42 +/- 0.28 (SD) nmoles bilirubin/10 mg protein/min; in CL, 2.15 +/- 1.34; in AL, 0.39 +/- 0.25; in RA, 0.58 +/- 0.37; in IA, 0.41 +/- 0.28; in HA, 2.56 +/- 1.40; and in SA, 1.72 +/- 1.06. BR activity, respectively, was in normal persons 8.7 +/- 2.4 (SD) nmoles bilirubin/10 mg protein/min; in CL, 13.6 +/- 9.1; in AL, 3.8 +/- 3.1 in RA, 5.1 +/- 2.7; in IA, 5.5 +/- 3.7; in HA, 17.0 +/- 7.2; and in SA, 10.5 +/- 4.2. On the basis of these findings it seems evident that both oxygenase and biliverdin reductase activities of the bone marrow are capable of adaptive regulation. The physiologic role of bone marrow in heme catabolism seems to be of significant importance.

  14. Gas-phase spectroscopy of ferric heme-NO complexes

    DEFF Research Database (Denmark)

    Wyer, J.A.; Jørgensen, Anders; Pedersen, Bjarke;


    Weakly bound complexes between ferric heme cations and NO were synthesised in the gas phase from ion-molecule reactions, and their absorption measured based on photodissociation yields. The Soret band, which serves as an important marker band for heme-protein spectroscopy, is maximal at 357±5 nm...

  15. Heme oxygenase-1 and carbon monoxide in pulmonary medicine

    NARCIS (Netherlands)

    Slebos, DJ; Ryter, SW; Choi, AMK


    Heme oxygenase-1 (HO-1), an inducible stress protein, confers cytoprotection against oxidative stress in vitro and in vivo. In addition to its physiological role in heme degradation, HO-1 may influence a number of cellular processes, including growth, inflammation, and apoptosis. By virtue of anti-i

  16. Spectroscopy of Ferric Heme and Protoporphyrin IX Ions In Vacuo

    DEFF Research Database (Denmark)

    Wyer, Jean; Nielsen, Steen Brøndsted


    This chapter deals with gas-phase spectroscopy of protoporphyrin IX and heme ions, two important biochromophores in nature. These ions strongly absorb blue and green light, which accounts for e.g. the red colour of blood. We present absorption spectra of four-coordinate ferric heme cations at room...

  17. Coadaptation and malaria control

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    Carlos Eduardo Tosta


    Full Text Available Malaria emerges from a disequilibrium of the system 'human-plasmodium-mosquito' (HPM. If the equilibrium is maintained, malaria does not ensue and the result is asymptomatic plasmodium infection. The relationships among the components of the system involve coadaptive linkages that lead to equilibrium. A vast body of evidence supports this assumption, including the strategies involved in the relationships between plasmodium and human and mosquito immune systems, and the emergence of resistance of plasmodia to antimalarial drugs and of mosquitoes to insecticides. Coadaptive strategies for malaria control are based on the following principles: (1 the system HPM is composed of three highly complex and dynamic components, whose interplay involves coadaptive linkages that tend to maintain the equilibrium of the system; (2 human and mosquito immune systems play a central role in the coadaptive interplay with plasmodium, and hence, in the mainten-ance of the system's equilibrium; the under- or overfunction of human immune system may result in malaria and influence its severity; (3 coadaptation depends on genetic and epigenetic phenomena occurring at the interfaces of the components of the system, and may involve exchange of infectrons (genes or gene fragments between the partners; (4 plasmodia and mosquitoes have been submitted to selective pressures, leading to adaptation, for an extremely long while and are, therefore, endowed with the capacity to circumvent both natural (immunity and artificial (drugs, insecticides, vaccines measures aiming at destroying them; (5 since malaria represents disequilibrium of the system HPM, its control should aim at maintaining or restoring this equilibrium; (6 the disequilibrium of integrated systems involves the disequilibrium of their components, therefore the maintenance or restoration of the system's equilibrium depend on the adoption of integrated and coordinated measures acting on all components, that means

  18. Extracellular heme uptake and the challenges of bacterial cell membranes. (United States)

    Smith, Aaron D; Wilks, Angela


    In bacteria, the fine balance of maintaining adequate iron levels while preventing the deleterious effects of excess iron has led to the evolution of sophisticated cellular mechanisms to obtain, store, and regulate iron. Iron uptake provides a significant challenge given its limited bioavailability and need to be transported across the bacterial cell wall and membranes. Pathogenic bacteria have circumvented the iron-availability issue by utilizing the hosts' heme-containing proteins as a source of iron. Once internalized, iron is liberated from the porphyrin enzymatically for cellular processes within the bacterial cell. Heme, a lipophilic and toxic molecule, poses a significant challenge in terms of transport given its chemical reactivity. As such, pathogenic bacteria have evolved sophisticated membrane transporters to coordinate, sequester, and transport heme. Recent advances in the biochemical and structural characterization of the membrane-bound heme transport proteins are discussed in the context of ligand coordination, protein-protein interaction, and heme transfer.

  19. Caenorhabditis elegans ATAD-3 modulates mitochondrial iron and heme homeostasis. (United States)

    van den Ecker, Daniela; Hoffmann, Michael; Müting, Gesine; Maglioni, Silvia; Herebian, Diran; Mayatepek, Ertan; Ventura, Natascia; Distelmaier, Felix


    ATAD3 (ATPase family AAA domain-containing protein 3) is a mitochondrial protein, which is essential for cell viability and organismal development. ATAD3 has been implicated in several important cellular processes such as apoptosis regulation, respiratory chain function and steroid hormone biosynthesis. Moreover, altered expression of ATAD3 has been associated with several types of cancer. However, the exact mechanisms underlying ATAD3 effects on cellular metabolism remain largely unclear. Here, we demonstrate that Caenorhabditis elegans ATAD-3 is involved in mitochondrial iron and heme homeostasis. Knockdown of atad-3 caused mitochondrial iron- and heme accumulation. This was paralleled by changes in the expression levels of several iron- and heme-regulatory genes as well as an increased heme uptake. In conclusion, our data indicate a regulatory role of C. elegans ATAD-3 in mitochondrial iron and heme metabolism.

  20. Multi-heme proteins: nature's electronic multi-purpose tool. (United States)

    Bewley, Kathryn D; Ellis, Katie E; Firer-Sherwood, Mackenzie A; Elliott, Sean J


    While iron is often a limiting nutrient to Biology, when the element is found in the form of heme cofactors (iron protoporphyrin IX), living systems have excelled at modifying and tailoring the chemistry of the metal. In the context of proteins and enzymes, heme cofactors are increasingly found in stoichiometries greater than one, where a single protein macromolecule contains more than one heme unit. When paired or coupled together, these protein associated heme groups perform a wide variety of tasks, such as redox communication, long range electron transfer and storage of reducing/oxidizing equivalents. Here, we review recent advances in the field of multi-heme proteins, focusing on emergent properties of these complex redox proteins, and strategies found in Nature where such proteins appear to be modular and essential components of larger biochemical pathways. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.

  1. Evaluation of unbound free heme in plant cells by differential acetone extraction. (United States)

    Espinas, Nino A; Kobayashi, Koichi; Takahashi, Shigekazu; Mochizuki, Nobuyoshi; Masuda, Tatsuru


    Heme functions not only as a prosthetic group of hemoproteins but also as a regulatory molecule, suggesting the presence of 'free' heme. Classically, total non-covalently bound heme is extracted from plant samples with acidic acetone after removal of pigments with basic and neutral acetone. Earlier work proposed that free heme can be selectively extracted into basic acetone. Using authentic hemoproteins, we confirmed that acidic acetone can quantitatively extract heme, while no heme was extracted into neutral acetone. Meanwhile, a certain amount of heme was extracted into basic acetone from hemoglobin and myoglobin. Moreover, basic acetone extracted loosely bound heme from bovine serum albumin, implying that the nature of hemoproteins largely influences heme extraction into basic acetone. Using a highly sensitive heme assay, we found that basic and neutral acetone can extract low levels of heme from plant samples. In addition, neutral acetone quantitatively extracted free heme when it was externally added to plant homogenates. Furthermore, the level of neutral acetone-extractable heme remained unchanged by precursor (5-aminolevulinic acid) feeding, while increased by norflurazon treatment which abolishes chloroplast biogenesis. However, changes in these heme levels did not correlate to genomes uncoupled phenotypes, suggesting that the level of unbound free heme would not affect retrograde signaling from plastids to the nucleus. The present data demonstrate that the combination of single-step acetone extraction following a sensitive heme assay is the ideal method for determining total and free heme in plants.

  2. Nanomedicine against malaria. (United States)

    Urbán, Patricia; Fernàndez-Busquets, Xavier


    Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium sp. The clinical, social and economic burden of malaria has led for the last 100 years to several waves of serious efforts to reach its control and eventual eradication, without success to this day. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial drugs exclusively to Plasmodium-infected cells. Different types of encapsulating structure, targeting molecule, and antimalarial compound will be discussed for the assembly of Trojan horse nanocapsules capable of targeting with complete specificity diseased cells and of delivering inside them their antimalarial cargo with the objective of eliminating the parasite with a single dose. Nanotechnology can also be applied to the discovery of new antimalarials through single-molecule manipulation approaches for the identification of novel drugs targeting essential molecular components of the parasite. Finally, methods for the diagnosis of malaria can benefit from nanotools applied to the design of microfluidic-based devices for the accurate identification of the parasite's strain, its precise infective load, and the relative content of the different stages of its life cycle, whose knowledge is essential for the administration of adequate therapies. The benefits and drawbacks of these nanosystems will be considered in different possible scenarios, including cost-related issues that might be hampering the development of nanotechnology-based medicines against malaria with the dubious argument that they are too expensive to be used in developing areas.

  3. Use of integrated malaria management reduces malaria in Kenya.

    Directory of Open Access Journals (Sweden)

    Bernard A Okech

    Full Text Available BACKGROUND: During an entomological survey in preparation for malaria control interventions in Mwea division, the number of malaria cases at the Kimbimbi sub-district hospital was in a steady decline. The underlying factors for this reduction were unknown and needed to be identified before any malaria intervention tools were deployed in the area. We therefore set out to investigate the potential factors that could have contributed to the decline of malaria cases in the hospital by analyzing the malaria control knowledge, attitudes and practices (KAP that the residents in Mwea applied in an integrated fashion, also known as integrated malaria management (IMM. METHODS: Integrated Malaria Management was assessed among community members of Mwea division, central Kenya using KAP survey. The KAP study evaluated community members' malaria disease management practices at the home and hospitals, personal protection measures used at the household level and malaria transmission prevention methods relating to vector control. Concurrently, we also passively examined the prevalence of malaria parasite infection via outpatient admission records at the major referral hospital in the area. In addition we studied the mosquito vector population dynamics, the malaria sporozoite infection status and entomological inoculation rates (EIR over an 8 month period in 6 villages to determine the risk of malaria transmission in the entire division. RESULTS: A total of 389 households in Mwea division were interviewed in the KAP study while 90 houses were surveyed in the entomological study. Ninety eight percent of the households knew about malaria disease while approximately 70% of households knew its symptoms and methods to manage it. Ninety seven percent of the interviewed households went to a health center for malaria diagnosis and treatment. Similarly a higher proportion (81% used anti-malarial medicines bought from local pharmacies. Almost 90% of households reported

  4. Frequently Asked Questions (FAQs) about Malaria (United States)

    ... disease maintains a vicious cycle of disease and poverty. Top of Page How People Get Malaria (Transmission) ... a list of all the places in the world where malaria transmission occurs and the malaria drugs ...

  5. Heme oxygenase-1 in Alzheimer disease: a tribute to Moussa Youdim. (United States)

    Schipper, Hyman M


    Heme oxygenase-1 (HO-1), a 32 kDa stress protein mediating the degradation of heme to ferrous iron, carbon monoxide and biliverdin/bilirubin, has been implicated in the pathogenesis of Alzheimer disease (AD) and other aging-related neurodegenerative disorders. In AD and mild cognitive impairment (MCI), immunoreactive HO-1 protein is over-expressed in astrocytes and neurons of the hippocampus and cerebral cortex and co-localizes to neurofibrillary tangles, senile plaques and corpora amylacea. Astroglial induction of the Hmox1 gene by β-amyloid, pro-inflammatory cytokines and hydrogen peroxide promotes mitochondrial sequestration of non-transferrin iron and macroautophagy and may thereby contribute to the pathological iron deposition and bioenergy failure amply documented in AD-affected neural tissues. Glial HO-1 expression may also impact cell survival and neuroplasticity in AD by modulating brain sterol/oxysterol metabolism and the degradation of tau by the proteasome. Suppression of glial HO-1 activity by pharmacological or other means may confer neuroprotection in AD by curtailing iron-mediated neurotoxicity.

  6. Electrochemical determination of heme-linked pKa values and the importance of using fluoride binding in heme proteins. (United States)

    Cerda, Jose F; Roeder, Margaret H; Houchins, Danielle N; Guzman, Carmen X; Amendola, Emily J; Castorino, Jacquelyn D; Fritz, Andrea L


    The ultraviolet-visible (UV-vis) spectroelectrochemical measurements of heme proteins in the presence of a heme-bound fluoride ion can be used as a probe for heme-linked ionizations of acid-base groups in the heme pocket. A detailed study of the pH dependence of the midpoint potential of skeletal horse myoglobin (Mb) with a heme-bound fluoride ion (Mb-F) reveals how protonation of the distal histidine (H64) changes the redox properties of the protein with a determined pKa of 5.3. In addition, fluoride binding in myoglobin provides a stabilization of -1.9 kcal/mol of the ferric Mb-F relative to ferric Mb without fluoride.


    Directory of Open Access Journals (Sweden)

    P. N. Harianto


    Full Text Available A retrospective study of cerebral malaria was performed in the Department of Internal Medicine, Bethesda Hospital - Tomohon, North Sulawesi, from January 1983 until October 1989. Among 2261 cases of malaria admitted in this hospital, there were 72 cases of cerebral malaria. The proportion of cerebral malaria cases increased from 0.8 % in 1983 to 6.4% in 1989. The mortality increased in the last 2 years, in spite of the same protocol-therapy in Bethesda Hospital. The total mortality was 30.5 %. There were 37 men and 35 women with an age distribution of 13-79 years. Parasitemia of more than 2 % occurs in 18 % and less than 2 % in 82 %. Complications were anemia 34%; hypoglycemia 9 %; creatinine 2 mg % in 36 %; hyponatremia 92 % and hyperbilirubenemia in 50 %. Several factors influencing the mortality were : Hypoglycemia less than 50 mg %Decreased conciousness level to sopor and comaCreatinine more than 2 mg %Total bilirubine more than 2 mg %More than one organ involvement for complications.Delayed and insufficient treatment.Probable resistence to treatment (quinine or chloroquine It is not certain which factors have a dominant role in mortality but in a condition with more than one  factor the mortality was very high.

  8. Heme binding properties of glyceraldehyde-3-phosphate dehydrogenase. (United States)

    Hannibal, Luciana; Collins, Daniel; Brassard, Julie; Chakravarti, Ritu; Vempati, Rajesh; Dorlet, Pierre; Santolini, Jérôme; Dawson, John H; Stuehr, Dennis J


    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a glycolytic enzyme that also functions in transcriptional regulation, oxidative stress, vesicular trafficking, and apoptosis. Because GAPDH is required for the insertion of cellular heme into inducible nitric oxide synthase [Chakravarti, R., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 18004-18009], we extensively characterized the heme binding properties of GAPDH. Substoichiometric amounts of ferric heme bound to GAPDH (one heme per GAPDH tetramer) to form a low-spin complex with UV-visible maxima at 362, 418, and 537 nm and when reduced to ferrous gave maxima at 424, 527, and 559 nm. Ferric heme association and dissociation rate constants at 10 °C were as follows: k(on) = 17800 M(-1) s(-1), k(off1) = 7.0 × 10(-3) s(-1), and k(off2) = 3.3 × 10(-4) s(-1) (giving approximate affinities of 19-390 nM). Ferrous heme bound more poorly to GAPDH and dissociated with a k(off) of 4.2 × 10(-3) s(-1). Magnetic circular dichroism, resonance Raman, and electron paramagnetic resonance spectroscopic data on the ferric, ferrous, and ferrous-CO complexes of GAPDH showed that the heme is bis-ligated with His as the proximal ligand. The distal ligand in the ferric complex was not displaced by CN(-) or N(3)(-) but in the ferrous complex could be displaced by CO at a rate of 1.75 s(-1) (for >0.2 mM CO). Studies with heme analogues revealed selectivity toward the coordinating metal and porphyrin ring structure. The GAPDH-heme complex was isolated from bacteria induced to express rabbit GAPDH in the presence of δ-aminolevulinic acid. Our finding of heme binding to GAPDH expands the protein's potential roles. The strength, selectivity, reversibility, and redox sensitivity of heme binding to GAPDH are consistent with it performing heme sensing or heme chaperone-like functions in cells.

  9. Increase on the initial soluble heme levels in acidic conditions is an important mechanism for spontaneous heme crystallization in vitro.

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    Renata Stiebler

    Full Text Available BACKGROUND: Hemozoin (Hz is a heme crystal that represents a vital pathway for heme disposal in several blood-feeding organisms. Recent evidence demonstrated that β-hematin (βH (the synthetic counterpart of Hz formation occurs under physiological conditions near synthetic or biological hydrophilic-hydrophobic interfaces. This seems to require a heme dimer acting as a precursor of Hz crystals that would be formed spontaneously in the absence of the competing water molecules bound to the heme iron. Here, we aimed to investigate the role of medium polarity on spontaneous βH formation in vitro. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the effect of water content on spontaneous βH formation by using the aprotic solvent dimethylsulfoxide (DMSO and a series of polyethyleneglycols (PEGs. We observed that both DMSO and PEGs (3.350, 6.000, 8.000, and 22.000 increased the levels of soluble heme under acidic conditions. These compounds were able to stimulate the production of βH crystals in the absence of any biological sample. Interestingly, the effects of DMSO and PEGs on βH formation were positively correlated with their capacity to promote previous heme solubilization in acidic conditions. Curiously, a short chain polyethyleneglycol (PEG 300 caused a significant reduction in both soluble heme levels and βH formation. Finally, both heme solubilization and βH formation strongly correlated with reduced medium water activity provided by increased DMSO concentrations. CONCLUSIONS: The data presented here support the notion that reduction of the water activity is an important mechanism to support spontaneous heme crystallization, which depends on the previous increase of soluble heme levels.

  10. The changing spectrum of severe falciparum malaria: a clinical study from Bikaner (northwest India

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    D.K. Kochar, S.K. Kochar, R.P. Agrawal, M. Sabir, K.C. Nayak, T.D. Agrawal, V.P. Purohit , R.P. Gupta


    Full Text Available Background & objectives: Recently there were reports from all over India about changing spectrumof clinical presentation of severe malaria. The present study was planned to study the same in thenorthwest India.Methods: This prospective study was conducted on patients of severe malaria admitted in a classifiedmalaria ward of a tertiary care hospital in Bikaner, Rajasthan (northwest India during 1994 and 2001.It included adult patients of both sexes belonging to all age groups. The diagnosis of Plasmodiumfalciparum was confirmed by demonstrating asexual form of parasites in peripheral blood smear. Allpatients were treated with i.v./oral quinine. The specific complications were treated by standard WHOprotocol. The data for individual complications for both the years were analysed by applying chisquaretest.Results: In a prospective study in 1994 the spectrum of complication was dominated by cerebralmalaria (25.75% followed by jaundice (11.47%, bleeding tendencies (9.59%, severe anaemia(5.83%, shock (5.26%, Acute respiratory distress syndrome—ARDS (3.01%, renal failure (2.07%and hypoglycemia (2.07% whereas in 2001 it was dominated by jaundice (58.85% followed bysevere anaemia (26.04%, bleeding tendencies (25.52%, shock (10.94%, cerebral malaria (10.94%,renal failure (6.25%, ARDS (2.08% and hypoglycemia (1.56%. The sharp difference for presence ofjaundice and severe anaemia in 2001 and cerebral malaria in 1994 was statistically significant. Similarly,the important cause of mortality in 2001 was multiple organ dysfunction syndrome (71.10% withpredominant presentation of jaundice and renal failure, whereas in 1994, it was cerebral malaria (77.96%.Interpretation & conclusion: The observation of changing spectrum of severe malaria in this studyand a significant increase in presentation with jaundice as an important manifestation is highly essentialfor primary, secondary and tertiary level health care providers for proper diagnosis and management.

  11. Cooperative coupling and role of heme a in the proton pump of heme-copper oxidases. (United States)

    Papa, S; Capitanio, N; Villani, G; Capitanio, G; Bizzoca, A; Palese, L L; Carlino, V; De Nitto, E


    In the last few years, evidence has accumulated supporting the applicability of the cooperative model of proton pumps in cytochrome systems, vectorial Bohr mechanisms, to heme-copper oxidases. The vectorial Bohr mechanism is based on short- and long-range protonmotive cooperative effects linked to redox transitions of the metal centers. The crystal structure of oxidized and reduced bovine-heart cytochrome c oxidase reveals, upon reduction, the occurrence of long-range conformational changes in subunit I of the oxidase. Analysis of the crystal structure of cytochrome c oxidase shows the existence of hydrogen-bonded networks of amino acid residues which could undergo redox-linked pK shifts resulting in transmembrane proton translocation. Our group has identified four proteolytic groups undergoing reversible redox-linked pK shifts. Two groups result in being linked to redox transitions of heme a3. One group is apparently linked to CuB. The fourth group is linked to oxido-reduction of heme a. We have shown that the proton transfer resulting from the redox Bohr effects linked to heme a and CuB in the bovine oxidase displays membrane vectorial asymmetry, i.e., protons are taken up from the inner aqueous space (N), upon reduction, and released in the external space (P), upon oxidation of the metals. This direction of proton uptake and release is just what is expected from the vectorial Bohr mechanism. The group linked to heme a, which can transfer up to 0.9 H+/e- at pHs around neutrality, can provide the major contribution to the proton pump. It is proposed that translocation of pumped protons, linked to electron flow through heme a, utilizes a channel (channel D) which extends from a conserved aspartate at the N entrance to a conserved glutamate located between heme a and the binuclear center. The carboxylic group of this glutamic acid, after having delivered, upon electron flow through heme a, pumped protons towards the P phase, once reprotonated from the N phase, moves

  12. Transfection of malaria parasites. (United States)

    Waters, A P; Thomas, A W; van Dijk, M R; Janse, C J


    The stable genetic transformation of three phylogenetically diverse species of Plasmodium, the parasitic etiological agent of malaria, is now possible. The parasite is haploid throughout the vast majority of its life cycle. Therefore with the single selectable marker activity and protocols currently available, it is possible not only to express introduced transgenes but also to study the effects of site-specific homologous recombination such as gene knockout. Transgene expression will allow the detailed study of many aspects of the cellular biology of malaria parasites, for example, the mechanisms underlying drug resistance and protein trafficking. We describe here the methods for propagation of the two animal models (Plasmodium berghei and Plasmodium knowlesi) and for transfection of these two species and the human parasite, Plasmodium falciparum. Examples of transgene expression are given.

  13. The use of activated protein C in severe Plasmodium falciparum malaria. (United States)

    Rankin, L G; Austin, D L H


    A 56-year-old man presented to a peripheral hospital in New Zealand with severe Plasmodium falciparum malaria with cerebral involvement and subsequently developed multi-system organ failure. Activated protein C was used in an attempt to stop the cascade of events into multi-organ failure. Severe infection with P. falciparum is life-threatening and appears to activate a hypercoagulable state similar to that of severe sepsis. Activated protein C is currently used in the treatment of severe sepsis and may provide a new adjuvant therapy for severe P. falciparum malaria.

  14. Malaria Genome Sequencing Project (United States)


    facts have stimulated efforts to develop an international, coordinated strategy for malaria research and control . Development of new drugs and...Interpolated Markov models for facilitate the development of new drugs and vaccines, the genome eukaryotic gene finding. Genomics 59, 24-31 (1999). of...Gardner, M. I. & Tettelin, H. Interpolated Markov models for facilitate the development of new drugs and vaccines, the genome eukaryotic gene finding

  15. Heme synthase (ferrochelatase) catalyzes the removal of iron from heme and demetalation of metalloporphyrins. (United States)

    Taketani, Shigeru; Ishigaki, Mutsumi; Mizutani, Atsushi; Uebayashi, Masashi; Numata, Masahiro; Ohgari, Yoshiko; Kitajima, Sakihito


    The red pigments in meat products, including cooked cured ham, arise from the reaction of myoglobin with nitric oxide generated from exogenous nitrite. Since carcinogenic nitrosoamines may be generated by the treatment of meats with nitrite, the production of nitrite-free meat products is an attractive alternative. Raw dry-cured (Parma) hams are produced by the treatment of meats with salts other than nitrite. Analysis of pigments in raw dry-cured hams reveals that the main pigment is zinc protoporphyrin, suggesting that the conversion of heme to zinc protoporphyrin occurs via an iron-removal reaction from myoglobin heme during the processing of raw hams. Purification of the iron-removal enzyme showed that it was identical to ferrochelatase. Recombinant ferrochelatase in combination with NADH-cytochrome b5 reductase catalyzed NADH-dependent iron-removal reaction from hemin and hemoproteins. Metal ions such as zinc and cobalt were also removed from the corresponding metalloporphyrins. The addition of zinc ions led to the formation of zinc protoporphyrin. In cultured cells, the conversion of zinc mesoporphyrin to mesoheme was observed to be dependent on ferrochelatase and could be markedly induced during erythroid differentiation. This is the first demonstration of a new enzyme reaction, the reverse reaction of ferrochelatase, which may contribute to a new route of the recycling of protoporphyrin and heme in cells.

  16. Magnetic and structural characterization of transition metal porphyrin complexes and the heme sites of heme peroxidases

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, K.R.


    Four studies of heme and heme model systems are described. The first study involves low temperature solution structural characterization of high-valent porphinatomanganese complexes via {sup 2}H- and {sup 13}C-NMR, and ESR spectroscopies. The reactive species were generated by low temperature reaction with chlorine (0) and chlorine(I) reagents. The implications of these species are discussed in terms of the relative reactivity of other +4 first row transition metal complexes and in terms of the catalytic effectiveness of porphinatomanganese (III) complexes in oxo-transfer reactions. The second study involved the analysis of isotropic {sup 2}H-NMR shifts observed for specifically deuterated chloro-N-methylporphinatomanganese(II) complexes. An ESR spectroscopic study of several ferrous heme peroxidase/NO complexes is presented. The {sup 14}N and {sup 15}N hyperfine splitting patterns and coupling constants in the ESR spectra clearly demonstrate the presence of a nitrogen-bound proximal ligand in lactoperoxidase. Finally, a catalytic autoxidation system involving cyclohexene and/or propanal as substrates is described. This reaction is catalyzed by high spin tetraarylporphinatoiron (III) complexes and evolves CO{sub 2}.

  17. Absorption by Isolated Ferric Heme Nitrosyl Cations In Vacuo

    DEFF Research Database (Denmark)

    Wyer, Jean; Nielsen, Steen Brøndsted


    Keywords:biophysics;gas-phase spectroscopy;heme proteins;mass spectrometry;nitric oxide Almost innocent: In photobiophysical studies of ferric heme nitrosyl complexes, the absorption spectra of six-coordinate complexes with NO and Met or Cys are similar to that of the five-coordinate complex ion ......(heme)(NO)+. Since the absorption spectra of related proteins with histidine as the proximal ligand are similar to those of the gaseous complexes, the protein microenvironment has little effect on the lowest-energy transition of the porphyrin macrocycle....

  18. Malaria Diagnostics Market grows with increasing public awareness on malaria


    Smita Deshmukh


    Transparency Market Research Reports incorporated a definite business overview and investigation inclines on "Malaria Diagnostics Market". This report likewise incorporates more illumination about fundamental review of the business including definitions, requisitions and worldwide business sector industry structure.   Read Full Report:

  19. On the molecular basis of the activity of the antimalarial drug chloroquine: EXAFS-assisted DFT evidence of a direct Fe-N bond with free heme in solution (United States)

    Macetti, Giovanni; Rizzato, Silvia; Beghi, Fabio; Silvestrini, Lucia; Lo Presti, Leonardo


    4-aminoquinoline antiplasmodials interfere with the biocrystallization of the malaria pigment, a key step of the malaria parasite metabolism. It is commonly believed that these drugs set stacking π···π interactions with the Fe-protoporphyrin scaffold of the free heme, even though the details of the heme:drug recognition process remain elusive. In this work, the local coordination of Fe(III) ions in acidic solutions of hematin at room temperature was investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy in the 4.0-5.5 pH range, both in the presence and in the absence of the antimalarial drug chloroquine. EXAFS results were complemented by DFT simulations in polarizable continuum media to model solvent effects. We found evidence that a complex where the drug quinoline nitrogen is coordinated with the iron center might coexist with formerly proposed adduct geometries, based on stacking interactions. Charge-assisted hydrogen bonds among lateral chains of the two molecules play a crucial role in stabilizing this complex, whose formation is favored by the presence of lipid micelles. The direct Fe-N bond could reversibly block the axial position in the Fe 1st coordination shell in free heme, acting as an inhibitor for the crystallization of the malaria pigment without permanently hampering the catalytic activity of the redox center. These findings are discussed in the light of possible implications on the engineering of drugs able to thwart the adaptability of the malaria parasite against classical aminoquinoline-based therapies.

  20. Polymorphisms in the Haem Oxygenase-1 promoter are not associated with severity of Plasmodium falciparum malaria in Ghanaian children

    DEFF Research Database (Denmark)

    Hansson, Helle H; Maretty, Lasse; Balle, Christina;


    (n=63) or cerebral malaria (n=132)). Furthermore, 287 individuals without a detectable Plasmodium infection or asymptomatic carriers of the parasite were enrolled as controls. Blood samples from participants were extracted for DNA and allele and genotype frequencies were determined with allele...

  1. Immunity to malaria in an era of declining malaria transmission. (United States)

    Fowkes, Freya J I; Boeuf, Philippe; Beeson, James G


    With increasing malaria control and goals of malaria elimination, many endemic areas are transitioning from high-to-low-to-no malaria transmission. Reductions in transmission will impact on the development of naturally acquired immunity to malaria, which develops after repeated exposure to Plasmodium spp. However, it is currently unclear how declining transmission and malaria exposure will affect the development and maintenance of naturally acquired immunity. Here we review the key processes which underpin this knowledge; the amount of Plasmodium spp. exposure required to generate effective immune responses, the longevity of antibody responses and the ability to mount an effective response upon re-exposure through memory responses. Lastly we identify research priorities which will increase our understanding of how changing transmission will impact on malarial immunity.

  2. Cerebral arterial spasm. II. Etiology and treatment of experimental cerebral vasospasm.

    Directory of Open Access Journals (Sweden)



    Full Text Available Delayed cerebral vasospams is caused by excessive accumulation of dopamine-beta-hydroxylase (DBH and noradrenaline in cerebral vessel walls. This study demonstrates the mechanisms of delayed spasm, particularly the role of red blood cell components, and the successful relief of delayed cerebral vasospasm. Spasmogenic substances which contained a heme component, such as methemoglobin, methemalbumin and catalase enhanced DBH activity in human serum as measured by a one step chemical spectrophotometric assay. The concentration which gave the highest DBH activity caused the maximum constriction of the basilar artery, when the substances were applied topically. Among components of red cells, methemoglobin, methemalbumin, catalase and nicotinamid adenin dinucleotide (NADH caused constriction of basilar artery in cats, when applied topically, whereas hematin, hemin and bilirubin caused no significant spasm. An oxyhemoglobin solution obtained by mixture with methemoglobin and ascorbic acid produced no significant vascular spasm either. Relief of delayed cerebral vasospasm was obtained with topical application of specific alpha adrenergic blocking drug such as phenoxybenzamine, specific inhibitors of DBH such as fusaric acid, o-phenanthroline and alphaalpha' dipyridyl beta2 adrenergic stimulants such as salbutamol, and a phosphodiesterase inhibitor, ascorbic acid.

  3. Malaria vaccine: a current perspective

    Directory of Open Access Journals (Sweden)

    Shobhona Sharma


    Full Text Available The observation that inactivated Plasmodium sporozoites could protect against malaria is about a hundred years old. However, systematic demonstration of protection using irradiated sporozoites occurred in the nineteen-sixties, providing the impetus for the development of a malaria vaccine. In 1983, the circumsporozoite protein (CSP, a major sporozoite surface antigen, became the first Plasmodium gene to be cloned, and a CSP-based vaccine appeared imminent. Today, 25 years later, we are still without an effective malaria vaccine, despite considerable information regarding the genomics and proteomics of the malaria parasites. Although clinical immunity to malaria has been well-documented in adults living in malaria endemic areas, our understanding of the host-immune responses operating in such malaria immune persons remains poor, and limits the development of immune control of the disease. Currently, several antigen and adjuvant combinations have entered clinical trials, in which efficacy against experimental sporozoite challenge and/or exposure to natural infection is evaluated. This review collates information on the recent status of the field. Unresolved challenges facing the development of a malaria vaccine are also discussed.

  4. Malaria during pregnancy in Rwanda

    NARCIS (Netherlands)

    Rulisa, S.


    It appears that malaria in Rwanda is not a major contributor to adverse outcomes of pregnancy anymore from a public health perspective but it can still give problems in individual patients, also in areas of low malaria transmission. This thesis shows that for individual cases the current treatment o

  5. Fats & Fakes : Towards improved control of malaria

    NARCIS (Netherlands)

    Visser, B.J.


    Effective malaria control reduced the malaria burden worldwide tremendously. Simultaneously, the epidemiology of malaria is changing and has become more complex. To continue the progress of the last decade, this thesis addressed several areas of importance in the field of malaria. Since effective ma

  6. Nitrite attenuated hypochlorous acid-mediated heme degradation in hemoglobin. (United States)

    Lu, Naihao; Li, Jiayu; Ren, Xiaoming; Tian, Rong; Peng, Yi-Yuan


    Hypochlorous acid (HOCl) is elevated in many inflammatory diseases and causes the accumulation of free iron. Through the Fenton reaction, free iron has the ability to generate free radicals and subsequently is toxic. Recent studies have demonstrated that HOCl participates in heme destruction of hemoglobin (Hb) and free iron release. In this study, it was showed that nitrite (NO2(-)) could prevent HOCl-mediated Hb heme destruction and free iron release. Also, NO2(-) prevented HOCl-mediated loss of Hb peroxidase activity. After the NO2(-)/HOCl treatment, Tyr 42 in α-chain was found to be nitrated in Hb, attenuating the electron transferring abilities of phenolic compounds. The protective effects of NO2(-) on HOCl-induced heme destruction were attributed to its reduction of ferryl Hb and/or direct scavenging of HOCl. Therefore, NO2(-) could show protective effects in some inflammatory diseases by preventing HOCl-mediated heme destruction of hemoproteins and free iron release.

  7. Immunolocalization of heme oxygenase-1 in periodontal diseases

    Directory of Open Access Journals (Sweden)

    G Gayathri


    Conclusion: The results of our study is an increasing evidence of involvement of antioxidant enzymes like heme oxygenase-1 in periodontal inflammation and their implication for treatment of chronic periodontitis.

  8. Heme crystallization in the midgut of triatomine insects. (United States)

    Oliveira, Marcus F; Gandara, Ana Caroline P; Braga, Cláudia M S; Silva, José R; Mury, Flavia B; Dansa-Petretski, Marílvia; Menezes, Diego; Vannier-Santos, Marcos A; Oliveira, Pedro L


    Hemozoin (Hz) is a heme crystal produced by several blood-feeding organisms in order to detoxify free heme released upon hemoglobin (Hb) digestion. Here we show that heme crystallization also occurs in three species of triatomine insects. Ultraviolet-visible and infrared light absorption spectra of insoluble pigments isolated from the midgut of three triatomine species Triatoma infestans, Dipetalogaster maximus and Panstrongylus megistus indicated that all produce Hz. Morphological analysis of T. infestans and D. maximus midguts revealed the close association of Hz crystals to perimicrovillar membranes and also as multicrystalline assemblies, forming nearly spherical structures. Heme crystallization was promoted by isolated perimicrovillar membranes from all three species of triatomine bugs in vitro in heat-sensitive reactions. In conclusion, the data presented here indicate that Hz formation is an ancestral adaptation of Triatominae to a blood-sucking habit and that the presence of perimicrovillar membranes plays a central role in this process.

  9. Cytochrome c peroxidase activity of heme bound amyloid β peptides. (United States)

    Seal, Manas; Ghosh, Chandradeep; Basu, Olivia; Dey, Somdatta Ghosh


    Heme bound amyloid β (Aβ) peptides, which have been associated with Alzheimer's disease (AD), can catalytically oxidize ferrocytochrome c (Cyt c(II)) in the presence of hydrogen peroxide (H2O2). The rate of catalytic oxidation of Cyt(II) c has been found to be dependent on several factors, such as concentration of heme(III)-Aβ, Cyt(II) c, H2O2, pH, ionic strength of the solution, and peptide chain length of Aβ. The above features resemble the naturally occurring enzyme cytochrome c peroxidase (CCP) which is known to catalytically oxidize Cyt(II) c in the presence of H2O2. In the absence of heme(III)-Aβ, the oxidation of Cyt(II) c is not catalytic. Thus, heme-Aβ complex behaves as CCP.

  10. Mechanisms of heme iron absorption: Current questions and controversies

    Institute of Scientific and Technical Information of China (English)


    Iron is a critical micronutrient, and iron derived from heme contributes a large proportion of the total iron absorbed in a typical Western diet. Heine iron is absorbed by different mechanisms than non-heine iron, but despite considerable study over many years these mechanisms remain poorly understood. This review provides an overview of the importance of heme iron in the diet and discusses the two prevailing hypotheses of heine absorption; namely receptor mediated endocytosis of heme, and direct transport into the intestinal enterocyte by recently discovered heine transporters. A specific emphasis is placed on the questions surrounding the site of heme catabolism and the identity of the enzyme that performs this task. Additionally, we present the hypothesis that a nonheme iron transport protein may be required for heine iron absorption and discuss the experiences of our laboratory in examining this hypothesis.

  11. Structure of the Escherichia coli O157:H7 heme oxygenase ChuS in complex with heme and enzymatic inactivation by mutation of the heme coordinating residue His-193

    Energy Technology Data Exchange (ETDEWEB)

    Suits,M.; Jaffer, N.; Jia, Z.


    Heme oxygenases catalyze the oxidation of heme to biliverdin, CO, and free iron. For pathogenic microorganisms, heme uptake and degradation are critical mechanisms for iron acquisition that enable multiplication and survival within hosts they invade. Here we report the first crystal structure of the pathogenic Escherichia coli O157:H7 heme oxygenase ChuS in complex with heme at 1.45 {angstrom} resolution. When compared with other heme oxygenases, ChuS has a unique fold, including structural repeats and a {beta}-sheet core. Not surprisingly, the mode of heme coordination by ChuS is also distinct, whereby heme is largely stabilized by residues from the C-terminal domain, assisted by a distant arginine from the N-terminal domain. Upon heme binding, there is no large conformational change beyond the fine tuning of a key histidine (His-193) residue. Most intriguingly, in contrast to other heme oxygenases, the propionic side chains of heme are orientated toward the protein core, exposing the {alpha}-meso carbon position where O{sub 2} is added during heme degradation. This unique orientation may facilitate presentation to an electron donor, explaining the significantly reduced concentration of ascorbic acid needed for the reaction. Based on the ChuS-heme structure, we converted the histidine residue responsible for axial coordination of the heme group to an asparagine residue (H193N), as well as converting a second histidine to an alanine residue (H73A) for comparison purposes. We employed spectral analysis and CO measurement by gas chromatography to analyze catalysis by ChuS, H193N, and H73A, demonstrating that His-193 is the key residue for the heme-degrading activity of ChuS.

  12. Genome-wide analysis reveals novel genes essential for heme homeostasis in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Scott Severance


    Full Text Available Heme is a cofactor in proteins that function in almost all sub-cellular compartments and in many diverse biological processes. Heme is produced by a conserved biosynthetic pathway that is highly regulated to prevent the accumulation of heme--a cytotoxic, hydrophobic tetrapyrrole. Caenorhabditis elegans and related parasitic nematodes do not synthesize heme, but instead require environmental heme to grow and develop. Heme homeostasis in these auxotrophs is, therefore, regulated in accordance with available dietary heme. We have capitalized on this auxotrophy in C. elegans to study gene expression changes associated with precisely controlled dietary heme concentrations. RNA was isolated from cultures containing 4, 20, or 500 microM heme; derived cDNA probes were hybridized to Affymetrix C. elegans expression arrays. We identified 288 heme-responsive genes (hrgs that were differentially expressed under these conditions. Of these genes, 42% had putative homologs in humans, while genomes of medically relevant heme auxotrophs revealed homologs for 12% in both Trypanosoma and Leishmania and 24% in parasitic nematodes. Depletion of each of the 288 hrgs by RNA-mediated interference (RNAi in a transgenic heme-sensor worm strain identified six genes that regulated heme homeostasis. In addition, seven membrane-spanning transporters involved in heme uptake were identified by RNAi knockdown studies using a toxic heme analog. Comparison of genes that were positive in both of the RNAi screens resulted in the identification of three genes in common that were vital for organismal heme homeostasis in C. elegans. Collectively, our results provide a catalog of genes that are essential for metazoan heme homeostasis and demonstrate the power of C. elegans as a genetic animal model to dissect the regulatory circuits which mediate heme trafficking in both vertebrate hosts and their parasites, which depend on environmental heme for survival.

  13. Combined measurement of soluble and cellular ICAM-1 among children with Plasmodium falciparum malaria in Uganda

    Directory of Open Access Journals (Sweden)

    Cserti-Gazdewich Christine M


    Full Text Available Abstract Background Intercellular adhesion molecule-1 (ICAM-1 is a cytoadhesion molecule implicated in the pathogenesis of Plasmodium falciparum malaria. Elevated levels of soluble ICAM-1 (sICAM-1 have previously been reported with increased malaria disease severity. However, studies have not yet examined both sICAM-1 concentrations and monocyte ICAM-1 expression in the same cohort of patients. To better understand the relationship of soluble and cellular ICAM-1 measurements in malaria, both monocyte ICAM-1 expression and sICAM-1 concentration were measured in children with P. falciparum infection exhibiting a spectrum of clinical severity. Methods Samples were analysed from 160 children, aged 0.5 to 10.8 years, with documented P. falciparum malaria in Kampala, Uganda. The patients belonged to one of three pre-study defined groups: uncomplicated malaria (UM, severe non-fatal malaria (SM-s, and fatal malaria (SM-f. Subset analysis was done on those with cerebral malaria (CM or severe malaria anaemia (SMA. Monocyte ICAM-1 was measured by flow cytometry. sICAM-1 was measured by enzyme immunoassay. Results Both sICAM-1 and monocyte cell-surface ICAM-1 followed a log-normal distribution. Median sICAM-1 concentrations increased with greater severity-of-illness: 279 ng/mL (UM, 462 ng/mL (SM-s, and 586 ng/mL (SM-f, p Conclusion In this cohort of children with P. falciparum malaria, sICAM-1 levels were associated with severity-of-illness. Patients with UM had higher monocyte ICAM-1 expression consistent with a role for monocyte ICAM-1 in immune clearance during non-severe malaria. Among the subsets of patients with either SMA or CM, monocyte ICAM-1 levels were higher in CM, consistent with the role of ICAM-1 as a marker of cytoadhesion. Categories of disease in pediatric malaria may exhibit specific combinations of soluble and cellular ICAM-1 expression.

  14. HmuS and HmuQ of Ensifer/Sinorhizobium meliloti degrade heme in vitro and participate in heme metabolism in vivo. (United States)

    Amarelle, Vanesa; Rosconi, Federico; Lázaro-Martínez, Juan Manuel; Buldain, Graciela; Noya, Francisco; O'Brian, Mark R; Fabiano, Elena


    Ensifer meliloti is a nitrogen-fixing symbiont of the alfalfa legume able to use heme as an iron source. The transport mechanism involved in heme acquisition in E. meliloti has been identified and characterized, but the fate of heme once inside the cell is not known. In silico analysis of E. meliloti 1021 genome revealed no canonical heme oxygenases although two genes encoding putative heme degrading enzymes, smc01518 and hmuS, were identified. SMc01518 is similar to HmuQ of Bradyrhizobium japonicum, which is weakly homologous to the Staphylococcus aureus IsdG heme-degrading monooxygenase, whereas HmuS is homolog to Pseudomonas aeruginosa PhuS, a protein reported as a heme chaperone and as a heme degrading enzyme. Recombinant HmuQ and HmuS were able to bind hemin with a 1:1 stoichiometry and displayed a Kd value of 5 and 4 µM, respectively. HmuS degrades heme in vitro to the biliverdin isomers IX-β and IX-δ in an equimolar ratio. The HmuQ recombinant protein degrades heme to biliverdin IX-δ only. Additionally, in this work we demonstrate that humS and hmuQ gene expression is regulated by iron and heme in a RirA dependent manner and that both proteins are involved in heme metabolism in E. meliloti in vivo.

  15. TMEM14C is required for erythroid mitochondrial heme metabolism (United States)

    Yien, Yvette Y.; Robledo, Raymond F.; Schultz, Iman J.; Takahashi-Makise, Naoko; Gwynn, Babette; Bauer, Daniel E.; Dass, Abhishek; Yi, Gloria; Li, Liangtao; Hildick-Smith, Gordon J.; Cooney, Jeffrey D.; Pierce, Eric L.; Mohler, Kyla; Dailey, Tamara A.; Miyata, Non; Kingsley, Paul D.; Garone, Caterina; Hattangadi, Shilpa M.; Huang, Hui; Chen, Wen; Keenan, Ellen M.; Shah, Dhvanit I.; Schlaeger, Thorsten M.; DiMauro, Salvatore; Orkin, Stuart H.; Cantor, Alan B.; Palis, James; Koehler, Carla M.; Lodish, Harvey F.; Kaplan, Jerry; Ward, Diane M.; Dailey, Harry A.; Phillips, John D.; Peters, Luanne L.; Paw, Barry H.


    The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in vivo and in cultured erythroid cells. In mice, TMEM14C deficiency resulted in porphyrin accumulation in the fetal liver, erythroid maturation arrest, and embryonic lethality due to profound anemia. Protoporphyrin IX synthesis in TMEM14C-deficient erythroid cells was blocked, leading to an accumulation of porphyrin precursors. The heme synthesis defect in TMEM14C-deficient cells was ameliorated with a protoporphyrin IX analog, indicating that TMEM14C primarily functions in the terminal steps of the heme synthesis pathway. Together, our data demonstrate that TMEM14C facilitates the import of protoporphyrinogen IX into the mitochondrial matrix for heme synthesis and subsequent hemoglobin production. Furthermore, the identification of TMEM14C as a protoporphyrinogen IX importer provides a genetic tool for further exploring erythropoiesis and congenital anemias. PMID:25157825

  16. Decreased Heme Oxygenase Activity in Patients with Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Berkay Cataloglu


    Full Text Available Alzheimer's disease is a neurodegenerative disorder characterized with progressive im-pairment of cognitive functions. Heme oxygenase is an enzyme that degrades the heme molecule resulting in equimolar amounts of the carbon monoxide, ferrous iron, and bili-verdin. Up to now, heme oxygenase activity and its metabolic effects in Alzheimer's dis-ease have been investigated in so many studies; most of them were performed in post-mortem brain tissues of Alzheimer's disease patients or in animal models. Therefore, we aimed to investigate heme oxygenase activity in leukocytes of Alzheimer's disease pa-tients as a peripheral sample. Mean heme oxygenase activity was significantly lower in patients with Alzheimer's disease (0.53 +/- 0.32 nmol/h/mg protein compared to control sucjects (1.19 +/- 0.84 nmol/h/mg protein (p= 0.001. We think that reduction in leukocyte heme oxygenase activity may limit disease progression through preserving peripheral mitochondrial function by reducing the formation of free iron and carbon monoxide. [Dis Mol Med 2013; 1(2.000: 31-34

  17. Alterations in renal heme biosynthesis during metal nephrotoxicity. (United States)

    Oskarsson, A; Fowler, B A


    The regulation of the heme biosynthetic pathway in the kidney by various metals has been reviewed. In addition, a study on the effects of lead on renal heme biosynthesis after acute treatment of rats has been reported. Chronic low-level lead exposure in rats results in relatively small effects on renal heme biosynthetic pathway enzymes. After acute treatment of rats with lead, no effects on ALAD or UROS and mild, transitory effects on ALAS and ferrochelatase are observed. The intracellular binding of lead within intranuclear inclusion bodies in the proximal tubule cells and to high-affinity cytosolic lead-binding proteins probably protects sensitive subcellular systems, such as the heme pathway, from lead toxicity. Chronic exposure to methyl mercury results in increased urinary excretion of uro- and coproporphyrins in rats, mediated via inhibition of ferrochelatase and UROS and stimulation of ALAS. A tissue-specific inhibition of ALAD occurs in the kidney after treatment of rats with indium. Acute treatment of rats with nickel, platinum, tin, antimony, bismuth, and cobalt results in induction of heme oxygenase, followed by decreased microsomal heme content and ALAS stimulation in the kidney.

  18. TMEM14C is required for erythroid mitochondrial heme metabolism. (United States)

    Yien, Yvette Y; Robledo, Raymond F; Schultz, Iman J; Takahashi-Makise, Naoko; Gwynn, Babette; Bauer, Daniel E; Dass, Abhishek; Yi, Gloria; Li, Liangtao; Hildick-Smith, Gordon J; Cooney, Jeffrey D; Pierce, Eric L; Mohler, Kyla; Dailey, Tamara A; Miyata, Non; Kingsley, Paul D; Garone, Caterina; Hattangadi, Shilpa M; Huang, Hui; Chen, Wen; Keenan, Ellen M; Shah, Dhvanit I; Schlaeger, Thorsten M; DiMauro, Salvatore; Orkin, Stuart H; Cantor, Alan B; Palis, James; Koehler, Carla M; Lodish, Harvey F; Kaplan, Jerry; Ward, Diane M; Dailey, Harry A; Phillips, John D; Peters, Luanne L; Paw, Barry H


    The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in vivo and in cultured erythroid cells. In mice, TMEM14C deficiency resulted in porphyrin accumulation in the fetal liver, erythroid maturation arrest, and embryonic lethality due to profound anemia. Protoporphyrin IX synthesis in TMEM14C-deficient erythroid cells was blocked, leading to an accumulation of porphyrin precursors. The heme synthesis defect in TMEM14C-deficient cells was ameliorated with a protoporphyrin IX analog, indicating that TMEM14C primarily functions in the terminal steps of the heme synthesis pathway. Together, our data demonstrate that TMEM14C facilitates the import of protoporphyrinogen IX into the mitochondrial matrix for heme synthesis and subsequent hemoglobin production. Furthermore, the identification of TMEM14C as a protoporphyrinogen IX importer provides a genetic tool for further exploring erythropoiesis and congenital anemias.

  19. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains

    DEFF Research Database (Denmark)

    Jespersen, Jakob S.; Wang, Christian W.; Mkumbaye, Sixbert I.;


    Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human...... endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR-binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full......-length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support...

  20. Mannose-binding lectin is a disease modifier in clinical malaria and may function as opsonin for Plasmodium falciparum-infected erythrocytes

    DEFF Research Database (Denmark)

    Garred, Peter; Nielsen, Morten A; Kurtzhals, Jørgen


    malarial anemia and children with uncomplicated malaria. However, patients with complicated malaria who were homozygous for MBL variant alleles had significantly higher parasite counts and lower blood glucose levels than their MBL-competent counterparts. Distinct calcium-dependent binding of MBL......Variant alleles in the mannose-binding lectin (MBL) gene (mbl2) causing low levels of functional MBL are associated with susceptibility to different infections and are common in areas where malaria is endemic. Therefore, we investigated whether MBL variant alleles in 551 children from Ghana were...... associated with the occurrence and outcome parameters of Plasmodium falciparum malaria and asked whether MBL may function as an opsonin for P. falciparum. No difference in MBL genotype frequency was observed between infected and noninfected children or between children with cerebral malaria and/or severe...

  1. A Research Agenda for Malaria Eradication: Vaccines




    Vaccines could be a crucial component of efforts to eradicate malaria. Current attempts to develop malaria vaccines are primarily focused on Plasmodium falciparum and are directed towards reducing morbidity and mortality. Continued support for these efforts is essential, but if malaria vaccines are to be used as part of a repertoire of tools for elimination or eradication of malaria, they will need to have an impact on malaria transmission. We introduce the concept of “vaccines that interrupt...



    Alessandro Bartoloni; Lorenzo Zammarchi


    The first symptoms of malaria, common to all the different malaria species, are nonspecific and mimic a flu-like syndrome. Although fever represents the cardinal feature, clinical findings in malaria are extremely diverse and may range in severity from mild headache to serious complications leading to death, particularly in falciparum malaria. As the progression to these complications can be rapid, any malaria patient must be assessed and treated rapidly, and frequent observations are needed ...

  3. Clinical aspects of uncomplicated and severe malaria


    Bartoloni A; Zammarchi L.


    The first symptoms of malaria, common to all the different malaria species, are nonspecific and mimic a flu-like syndrome. Although fever represents the cardinal feature, clinical findings in malaria are extremely diverse and may range in severity from mild headache to serious complications leading to death, particularly in falciparum malaria. As the progression to these complications can be rapid, any malaria patient must be assessed and treated rapidly, and frequent observations are needed ...

  4. Clinical Aspects of Uncomplicated and Severe Malaria


    Bartoloni, Alessandro; Zammarchi, Lorenzo


    The first symptoms of malaria, common to all the different malaria species, are nonspecific and mimic a flu-like syndrome. Although fever represents the cardinal feature, clinical findings in malaria are extremely diverse and may range in severity from mild headache to serious complications leading to death, particularly in falciparum malaria. As the progression to these complications can be rapid, any malaria patient must be assessed and treated rapidly, and frequent observations are needed ...

  5. Rapid reemergence of T cells into peripheral circulation following treatment of severe and uncomplicated Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Hviid, L; Kurtzhals, J A; Goka, B Q


    Frequencies and absolute numbers of peripheral T-cell subsets were monitored closely following acute Plasmodium falciparum malaria in 22 Ghanaian children from an area of hyperendemicity for seasonal malaria transmission. The children presented with cerebral or uncomplicated malaria (CM or UM......, respectively) or with severe malarial anemia. For all patients the frequencies and absolute numbers of peripheral T cells were lower than normal during the acute stage of disease. This lowering was most pronounced in the CM group and least pronounced in the UM group. Of particular interest, the CM patients...

  6. The effect of proteins from animal source foods on heme iron bioavailability in humans. (United States)

    Pizarro, Fernando; Olivares, Manuel; Valenzuela, Carolina; Brito, Alex; Weinborn, Valerie; Flores, Sebastián; Arredondo, Miguel


    Forty-five women (35-45 year) were randomly assigned to three iron (Fe) absorption sub-studies, which measured the effects of dietary animal proteins on the absorption of heme Fe. Study 1 was focused on heme, red blood cell concentrate (RBCC), hemoglobin (Hb), RBCC+beef meat; study 2 on heme, heme+fish, chicken, and beef; and study 3 on heme and heme+purified animal protein (casein, collagen, albumin). Study 1: the bioavailability of heme Fe from Hb was similar to heme only (∼13.0%). RBCC (25.0%) and RBCC+beef (21.3%) were found to be increased 2- and 1.6-fold, respectively, when compared with heme alone (pheme alone (10.3%) was reduced (pheme Fe absorption.

  7. A heme-binding domain controls regulation of ATP-dependent potassium channels. (United States)

    Burton, Mark J; Kapetanaki, Sofia M; Chernova, Tatyana; Jamieson, Andrew G; Dorlet, Pierre; Santolini, Jérôme; Moody, Peter C E; Mitcheson, John S; Davies, Noel W; Schmid, Ralf; Raven, Emma L; Storey, Nina M


    Heme iron has many and varied roles in biology. Most commonly it binds as a prosthetic group to proteins, and it has been widely supposed and amply demonstrated that subtle variations in the protein structure around the heme, including the heme ligands, are used to control the reactivity of the metal ion. However, the role of heme in biology now appears to also include a regulatory responsibility in the cell; this includes regulation of ion channel function. In this work, we show that cardiac KATP channels are regulated by heme. We identify a cytoplasmic heme-binding CXXHX16H motif on the sulphonylurea receptor subunit of the channel, and mutagenesis together with quantitative and spectroscopic analyses of heme-binding and single channel experiments identified Cys628 and His648 as important for heme binding. We discuss the wider implications of these findings and we use the information to present hypotheses for mechanisms of heme-dependent regulation across other ion channels.

  8. Analysis of Heme oxygenase isomers in rat

    Institute of Scientific and Technical Information of China (English)

    Zhen-Wei Xia; Wen-Jun Cui; Xue-Hong Zhang; Qing-Xiang Shen; Jian Wang; Yun-Zhu Li; Shen-Nian Chen; Shan-Chang Yu


    AIM: To purify and identify heme oxygenase (HO) isomers which exist in rat liver, spleen and brain treated with hematin and phenylhydrazine and in untreated rat liver and to investigate the characteristics of HO isomers, to isolate and confirm the rat HO-1 cDNA that actually encodes HO-1 by expressing cDNA in monkey kidney cells (COS-1 cells), to prepare the rat heme oxygenase-1 (HO-1) mutant and to detect inhibition of HO-1 mutated enzyme.METHODS: First, rat liver, spleen and brain microsomal fi-actions were purified by DEAE-Sephacel and hydroxylapatite. The characteristics including activity, immunity and inducibility of two isomers (HO-1 and HO-2), and their apparent molecular weight were measured by detecting enzymatic activities, SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting analysis, respectively. Second, plasmid pcDNA3HO1 containing native rat HO-1 cDNA and pcDNA3HO1D25 carrying mutated rat HO-1 cDNA (His25Ala) were constructed by site-directed mutagenesis. COS-1 cells transfected with pcDNA3HO1 and pcDNA3HO1D25 were collected and disrupted by sonication, the microsomes were prepared by ultracentrifugation. Third, the inhibition of rat HO-1 mutant was analyzed.RESULTS: Two isomers were purified and identified in treated rat liver, spleen, brain and untreated rat liver. HO-1 was the predominant form with a ratio of 2.0:1 and 3.2:1 of HO-1 and HO-2 in liver and spleen, respectively, but only the activity of HO-2 in the brain and untreated liver could be detected. The apparent molecular weights of HO-1 and HO-2 were about Mr 30 000 and Mr 36 000 under reducing conditions, respectively. The antiserum against liver HO-2 was employed in Western blotting analysis, the reactivity of HO-1 in the liver was not observed. The plasmid pcDNA3HO1 was highly expressed in endoplasmic reticulum of transfected COS-1 cells. The specific activity was ≈5-fold higher than that of the control. However, the enzyme activity of mutated HO-1 declined. While

  9. Chemical proteomics approach reveals the direct targets and the heme-dependent activation mechanism of artemisinin in Plasmodium falciparum using an activity-based artemisinin probe

    Directory of Open Access Journals (Sweden)

    Jigang Wang


    Full Text Available Artemisinin and its analogues are currently the most effective anti-malarial drugs. The activation of artemisinin requires the cleavage of the endoperoxide bridge in the presence of iron sources. Once activated, artemisinins attack macromolecules through alkylation and propagate a series of damages, leading to parasite death. Even though several parasite proteins have been reported as artemisinin targets, the exact mechanism of action (MOA of artemisinin is still controversial and its high potency and specificity against the malaria parasite could not be fully accounted for. Recently, we have developed an unbiased chemical proteomics approach to directly probe the MOA of artemisinin in P. falciparum. We synthesized an activity-based artemisinin probe with an alkyne tag, which can be coupled with biotin through click chemistry. This enabled selective purification and identification of 124 protein targets of artemisinin. Many of these targets are critical for the parasite survival. In vitro assays confirmed the specific artemisinin binding and inhibition of selected targets. We thus postulated that artemisinin kills the parasite through disrupting its biochemical landscape. In addition, we showed that artemisinin activation requires heme, rather than free ferrous iron, by monitoring the extent of protein binding using a fluorescent dye coupled with the alkyne-tagged artemisinin. The extremely high level of heme released from the hemoglobin digestion by the parasite makes artemisinin exceptionally potent against late-stage parasites (trophozoite and schizont stages compared to parasites at early ring stage, which have low level of heme, possibly derived from endogenous synthesis. Such a unique activation mechanism also confers artemisinin with extremely high specificity against the parasites, while the healthy red blood cells are unaffected. Our results provide a sound explanation of the MOA of artemisinin and its specificity against malaria

  10. Heme Degradation by Heme Oxygenase Protects Mitochondria but Induces ER Stress via Formed Bilirubin

    Directory of Open Access Journals (Sweden)

    Andrea Müllebner


    Full Text Available Heme oxygenase (HO, in conjunction with biliverdin reductase, degrades heme to carbon monoxide, ferrous iron and bilirubin (BR; the latter is a potent antioxidant. The induced isoform HO-1 has evoked intense research interest, especially because it manifests anti-inflammatory and anti-apoptotic effects relieving acute cell stress. The mechanisms by which HO mediates the described effects are not completely clear. However, the degradation of heme, a strong pro-oxidant, and the generation of BR are considered to play key roles. The aim of this study was to determine the effects of BR on vital functions of hepatocytes focusing on mitochondria and the endoplasmic reticulum (ER. The affinity of BR to proteins is a known challenge for its exact quantification. We consider two major consequences of this affinity, namely possible analytical errors in the determination of HO activity, and biological effects of BR due to direct interaction with protein function. In order to overcome analytical bias we applied a polynomial correction accounting for the loss of BR due to its adsorption to proteins. To identify potential intracellular targets of BR we used an in vitro approach involving hepatocytes and isolated mitochondria. After verification that the hepatocytes possess HO activity at a similar level as liver tissue by using our improved post-extraction spectroscopic assay, we elucidated the effects of increased HO activity and the formed BR on mitochondrial function and the ER stress response. Our data show that BR may compromise cellular metabolism and proliferation via induction of ER stress. ER and mitochondria respond differently to elevated levels of BR and HO-activity. Mitochondria are susceptible to hemin, but active HO protects them against hemin-induced toxicity. BR at slightly elevated levels induces a stress response at the ER, resulting in a decreased proliferative and metabolic activity of hepatocytes. However, the proteins that are targeted

  11. Heme-binding plasma membrane proteins of K562 erythroleukemia cells: Adsorption to heme-microbeads, isolation with affinity chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Majuri, R. (Minerva Foundation Institute for Medical Research, Helsinki (Finland))


    Heme-microbeads attached themselves to the surface of viable K562 cells in a manner inhibitable by free hemin, indicating heme-recptor interaction. The microbeads were at first evenly distributed, but after prolonged incubation at 37 deg. C they formed a cap on one pole of the cells indicating clustering of the membrane heme receptors. Membrane proteins were labeled by culturing the cells in the presence of {sup 35}S-methionine and were then solubilized with Triton X-114. The hydrophobic proteins contained about 20% of the total bound label. The solubilized membrane proteins were subsequently adsorbed to a heme-Sepharose affinity gel. According to SDS-electrophorsis and subsequent autoradiography, the immobilized heme captures two proteins or a protein with two polypeptides of 20 000 and 32 000 daltons. The larger of these was only wekly labeled with {sup 35}S. The same two bands were observed if the cell surface proteins were labeled with {sup 125}I by the lactoperoxidase method and the subsequently solubilized membrane proteins were isolated with heme-Sepharose. (author).

  12. Effective adjunctive therapy by an innate defense regulatory peptide in a preclinical model of severe malaria. (United States)

    Achtman, Ariel H; Pilat, Sandra; Law, Charity W; Lynn, David J; Janot, Laure; Mayer, Matt L; Ma, Shuhua; Kindrachuk, Jason; Finlay, B Brett; Brinkman, Fiona S L; Smyth, Gordon K; Hancock, Robert E W; Schofield, Louis


    Case fatality rates for severe malaria remain high even in the best clinical settings because antimalarial drugs act against the parasite without alleviating life-threatening inflammation. We assessed the potential for host-directed therapy of severe malaria of a new class of anti-inflammatory drugs, the innate defense regulator (IDR) peptides, based on host defense peptides. The Plasmodium berghei ANKA model of experimental cerebral malaria was adapted to use as a preclinical screen by combining late-stage intervention in established infections with advanced bioinformatic analysis of early transcriptional changes in co-regulated gene sets. Coadministration of IDR-1018 with standard first-line antimalarials increased survival of infected mice while down-regulating key inflammatory networks associated with fatality. Thus, IDR peptides provided host-directed adjunctive therapy for severe disease in combination with antimalarial treatment.

  13. Increased levels of inflammatory mediators in children with severe Plasmodium falciparum malaria with respiratory distress

    DEFF Research Database (Denmark)

    Awandare, Gordon A; Goka, Bamenla; Boeuf, Philippe


    circulating levels of mediators of inflammation--including the cytokines tumor necrosis factor (TNF)- alpha and interleukin (IL)-10; the chemokines macrophage inflammatory protein (MIP)-1 alpha , MIP-1 beta , and IL-8; and the immune activation marker neopterin--in children with RD, severe malarial anemia......BACKGROUND: Respiratory distress (RD), a symptom of underlying metabolic acidosis, has been identified as a major risk factor for mortality in children with severe malaria in Africa, yet the molecular mediators involved in the pathogenesis of RD have not been identified. METHODS: We studied...... (SMA), cerebral malaria (CM), and uncomplicated malaria (UM). RESULTS: Children with RD had significantly higher plasma levels of TNF- alpha , IL-10, and neopterin and a significantly higher TNF- alpha : IL-10 ratio than those without RD. In addition, the results demonstrated that, relative to UM, CM...

  14. A Murine Model to Study Epilepsy and SUDEP Induced by Malaria Infection (United States)

    Ssentongo, Paddy; Robuccio, Anna E.; Thuku, Godfrey; Sim, Derek G.; Nabi, Ali; Bahari, Fatemeh; Shanmugasundaram, Balaji; Billard, Myles W.; Geronimo, Andrew; Short, Kurt W.; Drew, Patrick J.; Baccon, Jennifer; Weinstein, Steven L.; Gilliam, Frank G.; Stoute, José A.; Chinchilli, Vernon M.; Read, Andrew F.; Gluckman, Bruce J.; Schiff, Steven J.


    One of the largest single sources of epilepsy in the world is produced as a neurological sequela in survivors of cerebral malaria. Nevertheless, the pathophysiological mechanisms of such epileptogenesis remain unknown and no adjunctive therapy during cerebral malaria has been shown to reduce the rate of subsequent epilepsy. There is no existing animal model of postmalarial epilepsy. In this technical report we demonstrate the first such animal models. These models were created from multiple mouse and parasite strain combinations, so that the epilepsy observed retained universality with respect to genetic background. We also discovered spontaneous sudden unexpected death in epilepsy (SUDEP) in two of our strain combinations. These models offer a platform to enable new preclinical research into mechanisms and prevention of epilepsy and SUDEP. PMID:28272506

  15. Current scenario of malaria vaccine

    Directory of Open Access Journals (Sweden)

    Jarnail Singh Braich


    Full Text Available Malaria is one of the deadliest infectious diseases that affects millions of people worldwide including India. As an addition to chemoprophylaxis and other antimalarial interventions malaria vaccine is under extensive research since decades. The vaccine development is more difficult to predict than drug development and presents a unique challenge as already there has been no vaccine effective against a parasite. Effective malaria vaccine could help eliminate and eradicate malaria; there are currently 63 vaccine candidates, 41 in preclinical and clinical stages of development. Vaccines are being designed to target pre-erythrocytic stages, erythrocytic stage or the sexual stages of Plasmodium taken up by a feeding mosquito, or the multiple stages. Two vaccines in preclinical and clinical development target P. falciparum; and the most advanced candidate is the pre-erythrocytic vaccine RTS,S which is in phase-III clinical trials. It is likely that world's first malaria vaccine will be available by 2015 at the country level. More efficacious second generation malaria vaccines are on the way to development. Safety, efficacy, cost and provision of the vaccine to all communities are major concerns in malaria vaccine issue. [Int J Basic Clin Pharmacol 2012; 1(2.000: 60-66

  16. The Role of the Cytoplasmic Heme-binding Protein (PhuS) of Pseudomonas aeruginosa in Intracellular Heme Trafficking and Iron Homeostasis*S⃞



    The cytoplasmic heme-binding protein PhuS, encoded within the Fur-regulated Pseudomonas heme utilization (phu) operon, has previously been shown to traffic heme to the iron-regulated heme oxygenase (HO). We further investigate the role of PhuS in heme trafficking to HO on disruption of the phuS and hemO genes in a Pseudomonas aeruginosa siderophore-deficient and wild-type background. Previous studies have shown that deletion of hemO prevents the cells from utilizin...

  17. Homologues of Neisserial Heme Oxygenase in Gram-Negative Bacteria: Degradation of Heme by the Product of the pigA Gene of Pseudomonas aeruginosa



    The oxidative cleavage of heme to release iron is a mechanism by which some bacterial pathogens can utilize heme as an iron source. The pigA gene of Pseudomonas aeruginosa is shown to encode a heme oxygenase protein, which was identified in the genome sequence by its significant homology (37%) with HemO of Neisseria meningitidis. When the gene encoding the neisserial heme oxygenase, hemO, was replaced with pigA, we demonstrated that pigA could functionally replace hemO and allow for heme util...

  18. Malaria haplotype frequency estimation. (United States)

    Wigger, Leonore; Vogt, Julia E; Roth, Volker


    We present a Bayesian approach for estimating the relative frequencies of multi-single nucleotide polymorphism (SNP) haplotypes in populations of the malaria parasite Plasmodium falciparum by using microarray SNP data from human blood samples. Each sample comes from a malaria patient and contains one or several parasite clones that may genetically differ. Samples containing multiple parasite clones with different genetic markers pose a special challenge. The situation is comparable with a polyploid organism. The data from each blood sample indicates whether the parasites in the blood carry a mutant or a wildtype allele at various selected genomic positions. If both mutant and wildtype alleles are detected at a given position in a multiply infected sample, the data indicates the presence of both alleles, but the ratio is unknown. Thus, the data only partially reveals which specific combinations of genetic markers (i.e. haplotypes across the examined SNPs) occur in distinct parasite clones. In addition, SNP data may contain errors at non-negligible rates. We use a multinomial mixture model with partially missing observations to represent this data and a Markov chain Monte Carlo method to estimate the haplotype frequencies in a population. Our approach addresses both challenges, multiple infections and data errors.

  19. Drug resistance in malaria

    Directory of Open Access Journals (Sweden)

    S C Parija


    Full Text Available Antimalarial chemotherapy is an important component of all malaria control programmes throughout the world. This is especially so in light of the fact that there are no antimalarial vaccines which are available for clinical use at present. Emergence and spread of malaria parasites which are resistant to many of the available antimalarials today is, therefore, a major cause for concern. Till date, resistance to all groups of antimalarials excluding artemisinin has been reported. In recent years, in vitro resistance to even artemisinin has been described. While resistance to antibacterial agents has come to prominence as a clinical problem in recent years, antiparasitic resistance in general and antimalarial resistance in particular has not received much attention, especially in the Indian scenario. The present review deals with commonly used antimalarial drugs and the mechanisms of resistance to them. Various methods of detecting antimalarial resistance and avoiding the same have also been dealt with. Newer parasite targets which can be used in developing newer antimalarial agents and antimalarials obtained from plants have also been mentioned.

  20. Malaria-associated peripheral gangrene

    Directory of Open Access Journals (Sweden)

    Deborah B. Martins


    Full Text Available Malaria is a common parasitic disease endemic in tropical and subtropical areas, including Mozambique. Symmetrical peripheral gangrene is a rare complication of malaria. The purpose of this study was to review cases of malaria-associated peripheral gangrene that were evaluated by the pediatric surgical service at Hospital Central. Four patients ranging in age from 11 months to 7 years with documented Plasmodium falciparum infection and peripheral gangrene were identified. Amputation was required in cases of wet-gangrene. The majority of cases were allowed to self-demarcate, and one was allowed to auto-amputate.

  1. Facile heme vinyl posttranslational modification in a hemoglobin. (United States)

    Preimesberger, Matthew R; Wenke, Belinda B; Gilevicius, Lukas; Pond, Matthew P; Lecomte, Juliette T J


    Iron-protoporphyrin IX, or b heme, is utilized as such by a large number of proteins and enzymes. In some cases, notably the c-type cytochromes, this group undergoes a posttranslational covalent attachment to the polypeptide chain, which adjusts the physicochemical properties of the holoprotein. The hemoglobin from the cyanobacterium Synechocystis sp. PCC 6803 (GlbN), contrary to the archetypical hemoglobin, modifies its b heme covalently. The posttranslational modification links His117, a residue that does not coordinate the iron, to the porphyrin 2-vinyl substituent and forms a hybrid b/c heme. The reaction is an electrophilic addition that occurs spontaneously in the ferrous state of the protein. This apparently facile type of heme modification has been observed in only two cyanobacterial GlbNs. To explore the determinants of the reaction, we examined the behavior of Synechocystis GlbN variants containing a histidine at position 79, which is buried against the porphyrin 4-vinyl substituent. We found that L79H/H117A GlbN bound the heme weakly but nevertheless formed a cross-link between His79 Nε2 and the heme 4-Cα. In addition to this linkage, the single variant L79H GlbN also formed the native His117-2-Cα bond yielding an unprecedented bis-alkylated protein adduct. The ability to engineer the doubly modified protein indicates that the histidine-heme modification in GlbN is robust and could be engineered in different local environments. The rarity of the histidine linkage in natural proteins, despite the ease of reaction, is proposed to stem from multiple sources of negative selection.

  2. Ultrafast Spectroscopy Evidence for Picosecond Ligand Exchange at the Binding Site of a Heme Protein: Heme-Based Sensor YddV. (United States)

    Lambry, Jean-Christophe; Stranava, Martin; Lobato, Laura; Martinkova, Marketa; Shimizu, Toru; Liebl, Ursula; Vos, Marten H


    An important question for the functioning of heme proteins is whether different ligands present within the protein moiety can readily exchange with heme-bound ligands. Studying the dynamics of the heme domain of the Escherichia coli sensor protein YddV upon dissociation of NO from the ferric heme by ultrafast spectroscopy, we demonstrate that when the hydrophobic leucine residue in the distal heme pocket is mutated to glycine, in a substantial fraction of the protein water replaces NO as an internal ligand in as fast as ∼4 ps. This process, which is near-barrierless and occurs orders of magnitude faster than the corresponding process in myoglobin, corresponds to a ligand swap of NO with a water molecule present in the heme pocket, as corroborated by molecular dynamics simulations. Our findings provide important new insight into ligand exchange in heme proteins that functionally interact with different external ligands.

  3. A potential role for plasma uric acid in the endothelial pathology of Plasmodium falciparum malaria.

    Directory of Open Access Journals (Sweden)

    Neida K Mita-Mendoza

    Full Text Available BACKGROUND: Inflammatory cytokinemia and systemic activation of the microvascular endothelium are central to the pathogenesis of Plasmodium falciparum malaria. Recently, 'parasite-derived' uric acid (UA was shown to activate human immune cells in vitro, and plasma UA levels were associated with inflammatory cytokine levels and disease severity in Malian children with malaria. Since UA is associated with endothelial inflammation in non-malaria diseases, we hypothesized that elevated UA levels contribute to the endothelial pathology of P. falciparum malaria. METHODOLOGY/PRINCIPAL FINDINGS: We measured levels of UA and soluble forms of intercellular adhesion molecule-1 (sICAM-1, vascular cell adhesion molecule-1 (sVCAM-1, E-selectin (sE-Selectin, thrombomodulin (sTM, tissue factor (sTF and vascular endothelial growth factor (VEGF in the plasma of Malian children aged 0.5-17 years with uncomplicated malaria (UM, n = 487 and non-cerebral severe malaria (NCSM, n = 68. In 69 of these children, we measured these same factors once when they experienced a malaria episode and twice when they were healthy (i.e., before and after the malaria transmission season. We found that levels of UA, sICAM-1, sVCAM-1, sE-Selectin and sTM increase during a malaria episode and return to basal levels at the end of the transmission season (p<0.0001. Plasma levels of UA and these four endothelial biomarkers correlate with parasite density and disease severity. In children with UM, UA levels correlate with parasite density (r = 0.092, p = 0.043, sICAM-1 (r = 0.255, p<0.0001 and sTM (r = 0.175, p = 0.0001 levels. After adjusting for parasite density, UA levels predict sTM levels. CONCLUSIONS/SIGNIFICANCE: Elevated UA levels may contribute to malaria pathogenesis by damaging endothelium and promoting a procoagulant state. The correlation between UA levels and parasite densities suggests that parasitized erythrocytes are one possible source of excess UA. UA-induced shedding of

  4. Malaria ecology and climate change (United States)

    McCord, G. C.


    Understanding the costs that climate change will exact on society is crucial to devising an appropriate policy response. One of the channels through while climate change will affect human society is through vector-borne diseases whose epidemiology is conditioned by ambient ecology. This paper introduces the literature on malaria, its cost on society, and the consequences of climate change to the physics community in hopes of inspiring synergistic research in the area of climate change and health. It then demonstrates the use of one ecological indicator of malaria suitability to provide an order-of-magnitude assessment of how climate change might affect the malaria burden. The average of Global Circulation Model end-of-century predictions implies a 47% average increase in the basic reproduction number of the disease in today's malarious areas, significantly complicating malaria elimination efforts.


    Directory of Open Access Journals (Sweden)

    H. A. Rafatjah


    Full Text Available Environmental management for malaria control is defined as any planned physical activities that through transformation of land, water and vegetation will result in the prevention, reduction or elimination of malaria. In planning and implementing these activities, full consideration must be given to their long-term effects and benefits and to the preservation of the quality of environment and they need to be fully and closely coordinated with water, land and agricultural development projects. Environmental management activities for malaria control can be classified as source reduction, dealing mainly with physical alteration of the environment; environmental manipulation, introducing temporary environmental changes and the reduction, and prevention of man-vector contact by site selection, mosquito proofing of dwellings and personal protection. For anti-malaria programs to employ these activities they need to re-train the staff, re-orient the services and set up pilot operations for feasibility studies.

  6. The March Toward Malaria Vaccines (United States)

    Hoffman, Stephen L.; Vekemans, Johan; Richie, Thomas L.; Duffy, Patrick E.


    In 2013 there were an estimated 584,000 deaths and 198 million clinical illnesses due to malaria, the majority in sub-Saharan Africa. Vaccines would be the ideal addition to the existing armamentarium of anti-malaria tools. However, malaria is caused by parasites, and parasites are much more complex in terms of their biology than the viruses and bacteria for which we have vaccines, passing through multiple stages of development in the human host, each stage expressing hundreds of unique antigens. This complexity makes it more difficult to develop a vaccine for parasites than for viruses and bacteria, since an immune response targeting one stage may not offer protection against a later stage, because different antigens are the targets of protective immunity at different stages. Furthermore, depending on the life cycle stage and whether the parasite is extra- or intra-cellular, antibody and/or cellular immune responses provide protection. It is thus not surprising that there is no vaccine on the market for prevention of malaria, or any human parasitic infection. In fact, no vaccine for any disease with this breadth of targets and immune responses exists. In this limited review, we focus on four approaches to malaria vaccines, (1) a recombinant protein with adjuvant vaccine aimed at Plasmodium falciparum (Pf) pre-erythrocytic stages of the parasite cycle (RTS,S/AS01), (2) whole sporozoite vaccines aimed at Pf pre-erythrocytic stages (PfSPZ Vaccine and PfSPZ-CVac), (3) prime boost vaccines that include recombinant DNA, viruses and bacteria, and protein with adjuvant aimed primarily at Pf pre-erythrocytic, but also asexual erythrocytic stages, and (4) recombinant protein with adjuvant vaccines aimed at Pf and Plasmodium vivax sexual erythrocytic and mosquito stages. We recognize that we are not covering all approaches to malaria vaccine development, or most of the critically important work on development of vaccines against P. vivax, the second most important cause of

  7. The march toward malaria vaccines. (United States)

    Hoffman, Stephen L; Vekemans, Johan; Richie, Thomas L; Duffy, Patrick E


    In 2013 there were an estimated 584,000 deaths and 198 million clinical illnesses due to malaria, the majority in sub-Saharan Africa. Vaccines would be the ideal addition to the existing armamentarium of anti-malaria tools. However, malaria is caused by parasites, and parasites are much more complex in terms of their biology than the viruses and bacteria for which we have vaccines, passing through multiple stages of development in the human host, each stage expressing hundreds of unique antigens. This complexity makes it more difficult to develop a vaccine for parasites than for viruses and bacteria, since an immune response targeting one stage may not offer protection against a later stage, because different antigens are the targets of protective immunity at different stages. Furthermore, depending on the life cycle stage and whether the parasite is extra- or intra-cellular, antibody and/or cellular immune responses provide protection. It is thus not surprising that there is no vaccine on the market for prevention of malaria, or any human parasitic infection. In fact, no vaccine for any disease with this breadth of targets and immune responses exists. In this limited review, we focus on four approaches to malaria vaccines, (1) a recombinant protein with adjuvant vaccine aimed at Plasmodium falciparum (Pf) pre-erythrocytic stages of the parasite cycle (RTS,S/AS01), (2) whole sporozoite vaccines aimed at Pf pre-erythrocytic stages (PfSPZ Vaccine and PfSPZ-CVac), (3) prime boost vaccines that include recombinant DNA, viruses and bacteria, and protein with adjuvant aimed primarily at Pf pre-erythrocytic, but also asexual erythrocytic stages, and (4) recombinant protein with adjuvant vaccines aimed at Pf and Plasmodium vivax sexual erythrocytic and mosquito stages. We recognize that we are not covering all approaches to malaria vaccine development, or most of the critically important work on development of vaccines against P. vivax, the second most important cause of

  8. Dietary iron controls circadian hepatic glucose metabolism through heme synthesis. (United States)

    Simcox, Judith A; Mitchell, Thomas Creighton; Gao, Yan; Just, Steven F; Cooksey, Robert; Cox, James; Ajioka, Richard; Jones, Deborah; Lee, Soh-Hyun; King, Daniel; Huang, Jingyu; McClain, Donald A


    The circadian rhythm of the liver maintains glucose homeostasis, and disruption of this rhythm is associated with type 2 diabetes. Feeding is one factor that sets the circadian clock in peripheral tissues, but relatively little is known about the role of specific dietary components in that regard. We assessed the effects of dietary iron on circadian gluconeogenesis. Dietary iron affects circadian glucose metabolism through heme-mediated regulation of the interaction of nuclear receptor subfamily 1 group d member 1 (Rev-Erbα) with its cosuppressor nuclear receptor corepressor 1 (NCOR). Loss of regulated heme synthesis was achieved by aminolevulinic acid (ALA) treatment of mice or cultured cells to bypass the rate-limiting enzyme in hepatic heme synthesis, ALA synthase 1 (ALAS1). ALA treatment abolishes differences in hepatic glucose production and in the expression of gluconeogenic enzymes seen with variation of dietary iron. The differences among diets are also lost with inhibition of heme synthesis with isonicotinylhydrazine. Dietary iron modulates levels of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a transcriptional activator of ALAS1, to affect hepatic heme. Treatment of mice with the antioxidant N-acetylcysteine diminishes PGC-1α variation observed among the iron diets, suggesting that iron is acting through reactive oxygen species signaling.

  9. DNA Sensors for Malaria Diagnosis

    DEFF Research Database (Denmark)

    Hede, Marianne Smedegaard; Fjelstrup, Søren; Knudsen, Birgitta R.


    In the field of malaria diagnosis much effort is put into the development of faster and easier alternatives to the gold standard, blood smear microscopy. Nucleic acid amplification based techniques pose some of the most promising upcoming diagnostic tools due to their potential for high sensitivi......, robustness and user-friendliness. In the current review, we will discuss some of the different DNA-based sensor systems under development for the diagnosis of malaria....

  10. Malaria's deadly grip

    DEFF Research Database (Denmark)

    Smith, Joseph D; Rowe, J Alexandra; Higgins, Matthew K;


    Cytoadhesion of Plasmodium falciparum-infected erythrocytes to host microvasculature is a key virulence determinant. Parasite binding is mediated by a large family of clonally variant adhesion proteins, termed P. falciparum erythrocyte membrane protein 1 (PfEMP1), encoded by var genes and expressed...... at the infected erythrocyte surface. Although PfEMP1 proteins have extensively diverged under opposing selection pressure to maintain ligand binding while avoiding antibody-mediated detection, recent work has revealed they can be classified into different groups based on chromosome location and domain composition....... This grouping reflects functional specialization of PfEMP1 proteins for different human host and microvascular binding niches and appears to be maintained by gene recombination hierarchies. Inone extreme, a specific PfEMP1 variant is associated with placental binding and malaria during pregnancy, while other PfEMP...

  11. Heme oxygenase-1 deletion affects stress erythropoiesis.

    Directory of Open Access Journals (Sweden)

    Yu-An Cao

    Full Text Available BACKGROUND: Homeostatic erythropoiesis leads to the formation of mature red blood cells under non-stress conditions, and the production of new erythrocytes occurs as the need arises. In response to environmental stimuli, such as bone marrow transplantation, myelosuppression, or anemia, erythroid progenitors proliferate rapidly in a process referred to as stress erythropoiesis. We have previously demonstrated that heme oxygenase-1 (HO-1 deficiency leads to disrupted stress hematopoiesis. Here, we describe the specific effects of HO-1 deficiency on stress erythropoiesis. METHODOLOGY/PRINCIPAL FINDINGS: We used a transplant model to induce stress conditions. In irradiated recipients that received hmox(+/- or hmox(+/+ bone marrow cells, we evaluated (i the erythrocyte parameters in the peripheral blood; (ii the staining intensity of CD71-, Ter119-, and CD49d-specific surface markers during erythroblast differentiation; (iii the patterns of histological iron staining; and (iv the number of Mac-1(+-cells expressing TNF-α. In the spleens of mice that received hmox(+/- cells, we show (i decreases in the proerythroblast, basophilic, and polychromatophilic erythroblast populations; (ii increases in the insoluble iron levels and decreases in the soluble iron levels; (iii increased numbers of Mac-1(+-cells expressing TNF-α; and (iv decreased levels of CD49d expression in the basophilic and polychromatophilic erythroblast populations. CONCLUSIONS/SIGNIFICANCE: As reflected by effects on secreted and cell surface proteins, HO-1 deletion likely affects stress erythropoiesis through the retention of erythroblasts in the erythroblastic islands of the spleen. Thus, HO-1 may serve as a therapeutic target for controlling erythropoiesis, and the dysregulation of HO-1 may be a predisposing condition for hematologic diseases.

  12. Molecular Factors and Biological Pathways Associated with Malaria Fever and the Pathogenesis of Cerebral Malaria (United States)


    Inference Package (Version 3.2). 5:164-166. 14. Freitas-Junior, L. H., R. Hernandez -Rivas, S. A. Ralph, D. Montiel-Condado, O. K. Ruvalcaba-Salazar, A. P... Rojas -Meza, L. Mancio-Silva, R. J. Leal- Silvestre, A. M. Gontijo, S. Shorte, and A. Scherf. 2005. Telomeric heterochromatin propagation and

  13. Employees with Cerebral Palsy (United States)

    ... problems in the muscles or nerves. Instead, faulty development or damage to motor areas in the brain disrupt the brain's ability to adequately control movement and posture (United Cerebral Palsy, 2010). "Cerebral" refers to the ...

  14. United Cerebral Palsy (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 ...

  15. Host immune response in returning travellers infected with malaria

    Directory of Open Access Journals (Sweden)

    MacMullin Gregory


    Full Text Available Abstract Background Clinical observations suggest that Canadian-born (CB travellers are prone to more severe malaria, characterized by higher parasite density in the blood, and severe symptoms, such as cerebral malaria and renal failure, than foreign-born travellers (FB from areas of malaria endemicity. It was hypothesized that host cytokine and chemokine responses differ significantly in CB versus FB patients returning with malaria, contributing to the courses of severity. A more detailed understanding of the profiles of cytokines, chemokines, and endothelial activation may be useful in developing biomarkers and novel therapeutic approaches for malaria. Materials and methods The patient population for the study (n = 186 was comprised of travellers returning to Toronto, Canada between 2007 and 2011. The patient blood samples’ cytokine, chemokine and angiopoietin concentrations were determined using cytokine multiplex assays, and ELISA assays. Results Significantly higher plasma cytokine levels of IL-12 (p40 were observed in CB compared to FB travellers, while epidermal growth factor (EGF was observed to be higher in FB than CB travellers. Older travellers (55 years old or greater with Plasmodium vivax infections had significantly higher mean cytokine levels for IL-6 and macrophage colony-stimulating factor (M-CSF than other adults with P. vivax (ages 18–55. Patients with P. vivax infections had significantly higher mean cytokine levels for monocyte chemotactic protein-1 (MCP-1, and M-CSF than patients with Plasmodium falciparum. Angiopoietin 2 (Ang-2 was higher for patients infected with P. falciparum than P. vivax, especially when comparing just the FB groups. IL-12 (p40 was higher in FB patients with P. vivax compared to P. falciparum. Il-12 (p40 was also higher in patients infected with P. vivax than those infected with Plasmodium ovale. For patients travelling to West Africa, IFN-γ and IL-6 was lower than for patients who were in other

  16. Variation in the ICAM1 gene is not associated with severe malaria phenotypes (United States)

    Fry, Andrew E.; Auburn, Sarah; Diakite, Mahamadou; Green, Angela; Richardson, Anna; Wilson, Jonathan; Jallow, Muminatou; Sisay-Joof, Fatou; Pinder, Margaret; Griffiths, Michael J.; Peshu, Norbert; Williams, Thomas N.; Marsh, Kevin; Molyneux, Malcolm E.; Taylor, Terrie E.; Rockett, Kirk A.; Kwiatkowski, Dominic P.


    Evidence from autopsy, mouse-model and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms around the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single-nucleotide-polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or ‘ICAM-1Kilifi’) and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1Kilifi were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96 – 1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97 – 1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence which links ICAM-1Kilifi to severe malaria susceptibility. PMID:18528404


    Directory of Open Access Journals (Sweden)

    Vijay Kuma


    Full Text Available : OBJECTIVES: Severe falciparum malaria is a critical illness resulting in multi-organ dysfunctions and death severe malaria is defined by the World Health Organization as qualitative variable. The purpose of this study is to devise a scoring system for predicting outcome in severe falciparum malaria. METHODS: 100 cases of sever falciparum malaria diagnosed as per the WHO criteria, were evaluated to determine the parameters which were significantly associated with mortality. Of all the parameters studied, five variables namely cerebral malaria (GCS3mg/dl, respiratory distress (Respiratory rate>24/min, jaundice (bilirubin >10mg/dl and Shock (Systolic BP<90mm of Hg. were all found to be associated with a poor prognosis. RESULTS: The five selected parameters were analyzed using the odds ratio and new scoring system named as GCRBS score was designed with a possible score from 0-10. With ac cut-off score of 5, the GCRBS score predicted mortality with a sensitivity of 85.3% and a specificity of 95.6%. CONCLUSION: The GCRBS score is an easy to calculate and apply. Of the 5 parameters, 3 are clinical which can be determined at beside and only 2 are biochemical which can be done in any laboratory. The most important advantage of this scoring system is that all the 5 parameters are to be assessed quantitatively for allotting a score, which would eliminate the possibility of observer bias.

  18. Plants used traditionally to treat malaria in Brazil: the archives of Flora Medicinal

    Directory of Open Access Journals (Sweden)

    Botsaris Alexandros S


    Full Text Available Abstract The archives of Flora Medicinal, an ancient pharmaceutical laboratory that supported ethnomedical research in Brazil for more than 30 years, were searched for plants with antimalarial use. Forty plant species indicated to treat malaria were described by Dr. J. Monteiro da Silva (Flora Medicinal leader and his co-workers. Eight species, Bathysa cuspidata, Cosmos sulphureus, Cecropia hololeuca, Erisma calcaratum, Gomphrena arborescens, Musa paradisiaca, Ocotea odorifera, and Pradosia lactescens, are related as antimalarial for the first time in ethnobotanical studies. Some species, including Mikania glomerata, Melampodium divaricatum, Galipea multiflora, Aspidosperma polyneuron, and Coutarea hexandra, were reported to have activity in malaria patients under clinical observation. In the information obtained, also, there were many details about the appropriate indication of each plant. For example, some plants are indicated to increase others' potency. There are also plants that are traditionally employed for specific symptoms or conditions that often accompany malaria, such as weakness, renal failure or cerebral malaria. Many plants that have been considered to lack activity against malaria due to absence of in vitro activity against Plasmodium can have other mechanisms of action. Thus researchers should observe ethnomedical information before deciding which kind of screening should be used in the search of antimalarial drugs.

  19. Porphyrin-Cored Polymer Nanoparticles: Macromolecular Models for Heme Iron Coordination. (United States)

    Rodriguez, Kyle J; Hanlon, Ashley M; Lyon, Christopher K; Cole, Justin P; Tuten, Bryan T; Tooley, Christian A; Berda, Erik B; Pazicni, Samuel


    Porphyrin-cored polymer nanoparticles (PCPNs) were synthesized and characterized to investigate their utility as heme protein models. Created using collapsible heme-centered star polymers containing photodimerizable anthracene units, these systems afford model heme cofactors buried within hydrophobic, macromolecular environments. Spectroscopic interrogations demonstrate that PCPNs display redox and ligand-binding reactivity similar to that of native systems and thus are potential candidates for modeling biological heme iron coordination.

  20. Effect of Growth Conditions on Yield and Heme Content of Vitreoscilla


    Lamba, Parveen; Webster, Dale A.


    Vitreoscilla, a gliding bacterium in the Beggiatoaceae, is an obligate aerobe in which cytochrome o functions as the terminal oxidase. Protoheme IX is the only heme type present in this organism. The yield and heme content of Vitreoscilla cells grown in yeast extract, peptone, and acetate were dependent on growth conditions. Cells harvested in early stationary phase contained roughly three times as much heme as cells in early log phase. There was an optimal shaking rate for maximum heme conte...

  1. Heme-Scavenging Role of alpha1-Microglobulin in Chronic Ulcers.


    Allhorn, Maria; Lundqvist, Katarina; Schmidtchen, Artur; Åkerström, Bo


    Chronic venous ulcers are characterized by chronic inflammation. Heme and iron, originating from blood cell hemolysis as well as extravascular necrosis, have been implicated as important pathogenic factors due to their promotion of oxidative stress. It was recently reported that the plasma and tissue protein alpha1-microglobulin is involved in heme metabolism. The protein binds heme, and a carboxy-terminally processed form, truncated alpha1-microglobulin, also degrades heme. Here, we show the...

  2. Dysfunction of the heme recycling system in heme oxygenase 1-deficient mice: effects on macrophage viability and tissue iron distribution. (United States)

    Kovtunovych, Gennadiy; Eckhaus, Michael A; Ghosh, Manik C; Ollivierre-Wilson, Hayden; Rouault, Tracey A


    To better understand the tissue iron overload and anemia previously reported in a human patient and mice that lack heme oxygenase-1 (HO-1), we studied iron distribution and pathology in HO-1(Hmox1)(-/-) mice. We found that resident splenic and liver macrophages were mostly absent in HO-1(-/-) mice. Erythrophagocytosis caused the death of HO-1(-/-) macrophages in in vitro experiments, supporting the hypothesis that HO-1(-/-) macrophages died of exposure to heme released on erythrophagocytosis. Rupture of HO-1(-/-) macrophages in vivo and release of nonmetabolized heme probably caused tissue inflammation. In the spleen, initial splenic enlargement progressed to red pulp fibrosis, atrophy, and functional hyposplenism in older mice, recapitulating the asplenia of an HO-1-deficient patient. We postulate that the failure of tissue macrophages to remove senescent erythrocytes led to intravascular hemolysis and increased expression of the heme and hemoglobin scavenger proteins, hemopexin and haptoglobin. Lack of macrophages expressing the haptoglobin receptor, CD163, diminished the ability of haptoglobin to neutralize circulating hemoglobin, and iron overload occurred in kidney proximal tubules, which were able to catabolize heme with HO-2. Thus, in HO-1(-/-) mammals, the reduced function and viability of erythrophagocytosing macrophages are the main causes of tissue damage and iron redistribution.

  3. [Current malaria situation in Turkey]. (United States)

    Gockchinar, T; Kalipsi, S


    Geographically, Turkey is situated in an area where malaria is very risky. The climatic conditions in the region are suitable for the malaria vector to proliferate. Due to agricultural infrastructural changes, GAP and other similar projects, insufficient environmental conditions, urbanization, national and international population moves, are a key to manage malaria control activities. It is estimated that malaria will be a potential danger for Turkey in the forthcoming years. The disease is located largely in south-eastern Anatolia. The Diyarbakir, Batman, Sanliurfa, Siirt, and Mardin districts are the most affected areas. In western districts, like Aydin and Manisa, an increase in the number of indigenous cases can be observed from time to time. This is due to workers moving from malaria districts to western parts to final work. Since these workers cannot be controlled, the population living in these regions get infected from indigenous cases. There were 84,345 malaria cases in 1994 and 82,096 in 1995, they decreased to 60,884 in 1996 and numbered 35,456 in 1997. They accounted for 36,842 and 20,963 in 1998 and 1999, respectively. In Turkey there are almost all cases of P. vivax malaria. There are also P. vivax and P. falciparum malaria cases coming from other countries: There were 321 P. vivax cases, including 2 P. falciparum ones, arriving to Turkey from Iraq in 1995. The P. vivax malaria cases accounted for 229 in 1996, and 67, cases P. vivax including 12 P. falciparum cases, in 1997, and 4 P. vivax cases in 1998 that came from that country. One P. vivax case entered Turkey from Georgia in 1998. The cause of higher incidence of P. vivax cases in 1995, it decreasing in 1999, is the lack of border controls over workers coming to Turkey. The other internationally imported cases are from Syria, Sudan, Pakistan, Afghanistan, Nigeria, India, Azerbaijan, Malaysia, Ghana, Indonesia, Yemen. Our examinations have shown that none of these internationally imported cases

  4. Features and outcomes of malaria infection in glucose-6-phosphatedehydrogenase normal and deficient Nigerian children

    Directory of Open Access Journals (Sweden)

    Adebola Emmanuel Orimadegun


    Full Text Available Background & objectives: Malaria and G6PD deficiency-related haemolyses are known causes of hospital admissions in Nigeria and pose great danger to child survival but data on interactions of these two pathologies are scarce. This study was carried out to determine the association between features of Plasmodium falciparum infection and G6PD status. Methods: G6PD and haemoglobin were typed by fluorescent spot test and electrophoresis respectively, in 1120 children with microscopically-proven falciparum malaria. Clinical features of malaria were compared between G6PD normal and deficient children. Results: There were 558 males and 562 females with median age of 35 months (range, 6 months-12 yr. In males, prevalence of G6PD-deficiency in patients with uncomplicated malaria (UM, severe malarial anaemia (SMA and cerebral malaria (CM was 23.4, 7 and 16.7%, respectively compared with 11.1, 7.3 and 4.4%, respectively among females. In both males and females, convulsion and rectal temperature above 38°C were less likely presentations among G6PD-deficient compared with G6PD-normal children (p <0.05. The proportions of children with pallor, convulsion and impaired consciousness were significantly lower among G6PD-deficient than normal males (p <0.05 but these features were not different between deficient and normal females (p >0.05. Interpretation & conclusion: Convulsions, pallor and elevated temperature were more frequent features of malaria in G6PD normal than deficient children. G6PD-deficient male children are protected against impaired consciousness. These differences may offer useful hints in malaria treatment and researches in endemic regions.

  5. Degradation of heme in gram-negative bacteria: the product of the hemO gene of Neisseriae is a heme oxygenase. (United States)

    Zhu, W; Wilks, A; Stojiljkovic, I


    A full-length heme oxygenase gene from the gram-negative pathogen Neisseria meningitidis was cloned and expressed in Escherichia coli. Expression of the enzyme yielded soluble catalytically active protein and caused accumulation of biliverdin within the E. coli cells. The purified HemO forms a 1:1 complex with heme and has a heme protein spectrum similar to that previously reported for the purified heme oxygenase (HmuO) from the gram-positive pathogen Corynebacterium diphtheriae and for eukaryotic heme oxygenases. The overall sequence identity between HemO and these heme oxygenases is, however, low. In the presence of ascorbate or the human NADPH cytochrome P450 reductase system, the heme-HemO complex is converted to ferric-biliverdin IXalpha and carbon monoxide as the final products. Homologs of the hemO gene were identified and characterized in six commensal Neisseria isolates, Neisseria lactamica, Neisseria subflava, Neisseria flava, Neisseria polysacchareae, Neisseria kochii, and Neisseria cinerea. All HemO orthologs shared between 95 and 98% identity in amino acid sequences with functionally important residues being completely conserved. This is the first heme oxygenase identified in a gram-negative pathogen. The identification of HemO as a heme oxygenase provides further evidence that oxidative cleavage of the heme is the mechanism by which some bacteria acquire iron for further use.

  6. Giardia intestinalis incorporates heme into cytosolic cytochrome b₅. (United States)

    Pyrih, Jan; Harant, Karel; Martincová, Eva; Sutak, Robert; Lesuisse, Emmanuel; Hrdý, Ivan; Tachezy, Jan


    The anaerobic intestinal pathogen Giardia intestinalis does not possess enzymes for heme synthesis, and it also lacks the typical set of hemoproteins that are involved in mitochondrial respiration and cellular oxygen stress management. Nevertheless, G. intestinalis may require heme for the function of particular hemoproteins, such as cytochrome b5 (cytb5). We have analyzed the sequences of eukaryotic cytb5 proteins and identified three distinct cytb5 groups: group I, which consists of C-tail membrane-anchored cytb5 proteins; group II, which includes soluble cytb5 proteins; and group III, which comprises the fungal cytb5 proteins. The majority of eukaryotes possess both group I and II cytb5 proteins, whereas three Giardia paralogs belong to group II. We have identified a fourth Giardia cytb5 paralog (gCYTb5-IV) that is rather divergent and possesses an unusual 134-residue N-terminal extension. Recombinant Giardia cytb5 proteins, including gCYTb5-IV, were expressed in Escherichia coli and exhibited characteristic UV-visible spectra that corresponded to heme-loaded cytb5 proteins. The expression of the recombinant gCYTb5-IV in G. intestinalis resulted in the increased import of extracellular heme and its incorporation into the protein, whereas this effect was not observed when gCYTb5-IV containing a mutated heme-binding site was expressed. The electrons for Giardia cytb5 proteins may be provided by the NADPH-dependent Tah18-like oxidoreductase GiOR-1. Therefore, GiOR-1 and cytb5 may constitute a novel redox system in G. intestinalis. To our knowledge, G. intestinalis is the first anaerobic eukaryote in which the presence of heme has been directly demonstrated.

  7. Developmental expression of heme oxygenase in the rat lung. (United States)

    Dennery, Phyllis A; Lee, Christen S; Ford, Berendera S; Weng, Yi-Hao; Yang, Guang; Rodgers, Pamela A


    Heme oxygenase (HO), the rate-limiting enzyme in the formation of bilirubin, is expressed in the lung and may serve as an antioxidant. This enzyme results in the formation of antioxidant bile pigments and the degradation of pro-oxidant heme. We wanted to evaluate the differences in expression of HO-1, the inducible form, and HO-2, the constitutive isoenzyme, during lung maturation and document whether lung HO expression was similar to that of other antioxidant enzymes. Lung total HO activity and HO-1 and HO-2 proteins as well as HO-1 and HO-2 mRNA were evaluated in animals from 16 d of gestation (e(16.5)) to 2 mo of age. Heme content was also evaluated because heme is the substrate of the reaction. HO-1 mRNA was maximal at e(19.5) and e(20.5), whereas HO-2 mRNA was not changed throughout maturation. Lung HO-1 protein was highest on the first days of life and lowest in adults, whereas HO-2 protein was maximally expressed at postnatal d 5 and then declined to reach adult values. As to HO activity, there was a prenatal peak at e(20.5), a second lesser peak at d 5, and thereafter a decline to adult values. Lung heme content was inversely correlated with HO activity or protein as the highest heme values were seen in adults with the lowest HO activity. In response to hyperoxia, HO-1 mRNA was induced only in the adult lungs. A better understanding of the maturational regulation of lung HO will define a role for HO in newborns at risk for oxygen toxicity.

  8. Genetic analyses of heme oxygenase 1 (HMOX1) in different forms of pancreatitis

    NARCIS (Netherlands)

    Weis, S.; Jesinghaus, M.; Kovacs, P.; Schleinitz, D.; Schober, R.; Ruffert, C.; Herms, M.; Wittenburg, H.; Stumvoll, M.; Blüher, M.; Grützmann, R.; Schulz, H.U.; Keim, V.; Mössner, J.; Bugert, P.; Witt, H.; Drenth, J.P.H.; Krohn, K.; Rosendahl, J.


    BACKGROUND: Heme oxygenase 1 (HMOX1) is the rate limiting enzyme in heme degradation and a key regulator of inflammatory processes. In animal models the course of pancreatitis was ameliorated by up-regulation of HMOX1 expression. Additionally, carbon monoxide released during heme breakdown inhibited

  9. Heme uptake by Leishmania amazonensis is mediated by the transmembrane protein LHR1.

    Directory of Open Access Journals (Sweden)

    Chau Huynh

    Full Text Available Trypanosomatid protozoan parasites lack a functional heme biosynthetic pathway, so must acquire heme from the environment to survive. However, the molecular pathway responsible for heme acquisition by these organisms is unknown. Here we show that L. amazonensis LHR1, a homolog of the C. elegans plasma membrane heme transporter HRG-4, functions in heme transport. Tagged LHR1 localized to the plasma membrane and to endocytic compartments, in both L. amazonensis and mammalian cells. Heme deprivation in L. amazonensis increased LHR1 transcript levels, promoted uptake of the fluorescent heme analog ZnMP, and increased the total intracellular heme content of promastigotes. Conversely, deletion of one LHR1 allele reduced ZnMP uptake and the intracellular heme pool by approximately 50%, indicating that LHR1 is a major heme importer in L. amazonensis. Viable parasites with correct replacement of both LHR1 alleles could not be obtained despite extensive attempts, suggesting that this gene is essential for the survival of promastigotes. Notably, LHR1 expression allowed Saccharomyces cerevisiae to import heme from the environment, and rescued growth of a strain deficient in heme biosynthesis. Syntenic genes with high sequence identity to LHR1 are present in the genomes of several species of Leishmania and also Trypanosoma cruzi and Trypanosoma brucei, indicating that therapeutic agents targeting this transporter could be effective against a broad group of trypanosomatid parasites that cause serious human disease.

  10. XAFS Debye-Waller factors for deformed hemes and metal substituted hemes

    Energy Technology Data Exchange (ETDEWEB)

    Dimakis, N; Mion, T; Ramirez, C [Department of Physics and Geology, University of Texas-Pan American, Edinburg, TX 78539 (United States); Bunker, G, E-mail: dimakis@utpa.ed [Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616 (United States)


    We present an efficient and accurate method for calculating XAFS Debye-Waller factors for deformed active sites of hemoproteins and metal substituted hemes. Based on the Normal Coordinate Structural Decomposition scheme, the deformation of the porphyrin macrocycle is expressed as a linear combination of the normal modes of the planar species. In our approach, we identify the modes that contribute most to the deformation. Small metal-porphyrin structures which match the macrocycle structural deformation of the deformed hemoprotein site are used to calculate the Debye-Waller parameters at sample's temperature. The Debye-Waller factors are directly obtained by calculating the normal mode spectrum of the corresponding metal-porphyrin structure using Density Functional Theory. Our method is tested on Ni-tetraadamantyl porphyrin and cytochrome c structures with more than 500 available scattering paths.

  11. The antibody response to well-defined malaria antigens after acute malaria in individuals living under continuous malaria transmission

    DEFF Research Database (Denmark)

    Petersen, E; Høgh, B; Dziegiel, M


    , and a synthetic peptide (EENV)6 representing the C-terminal repeats from Pf155/RESA, were investigated longitudinally in 13 children and 7 adults living under conditions of continuous, intense malaria transmission. Some subjects did not recognize the antigens after malaria infection, and in subjects recognizing...... elicited by natural malaria infection in previously primed donors....

  12. Heme oxygenase-1 system and gastrointestinal inflammation: a short review. (United States)

    Zhu, Xiao; Fan, Wen-Guo; Li, Dong-Pei; Kung, Hsiangfu; Lin, Marie Cm


    Heme oxygenase-1 (HO-1) system catalyzes heme to biologically active products: carbon monoxide, biliverdin/bilirubin and free iron. It is involved in maintaining cellular homeostasis and many physiological and pathophysiological processes. A growing body of evidence indicates that HO-1 activation may play an important protective role in acute and chronic inflammation of gastrointestinal tract. This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal inflammation studied to date. The ability to upregulate HO-1 by pharmacological means or using gene therapy may offer therapeutic strategies for gastrointestinal inflammation in the future.

  13. EU grid computing effort takes on malaria

    CERN Multimedia

    Lawrence, Stacy


    Malaria is the world's most common parasitic infection, affecting more thatn 500 million people annually and killing more than 1 million. In order to help combat malaria, CERN has launched a grid computing effort (1 page)

  14. Complement activation in experimental human malaria infection.

    NARCIS (Netherlands)

    Roestenberg, M.; McCall, M.B.B.; Mollnes, T.E.; Deuren, M. van; Sprong, T.; Klasen, I.S.; Hermsen, C.C.; Sauerwein, R.W.; Ven, A.J.A.M. van der


    The objective of this study was to investigate complement activation in uncomplicated, early phases of human malaria. Fifteen healthy volunteers were experimentally infected with Plasmodium falciparum malaria. Parasitemia and complement activation products were assessed. During blood stage parasitem

  15. Strategies For Malaria Control In Mangalore City


    Kiran Udaya .N


    Research questions: What different strategies should be used to effectively control problem of malaria? Objectives: 1) To study the problem of malaria. 2) To study different strategies for effective control of malaria. Study design: Observational and record based. The problem of malaria was studied for three years from 1996-1998 Participants: Individuals having fever. Setting: Community based in Mangalore City. Study variables: Fever cases, blood slides prepared, slides found positive, agency...

  16. Cerebral microangiopathies; Zerebrale Mikroangiopathien

    Energy Technology Data Exchange (ETDEWEB)

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


    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.)

  17. Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex. (United States)

    Girvan, Hazel M; Bradley, Justin M; Cheesman, Myles R; Kincaid, James R; Liu, Yilin; Czarnecki, Kazimierz; Fisher, Karl; Leys, David; Rigby, Stephen E J; Munro, Andrew W


    DGCR8 is the RNA-binding partner of the nuclease Drosha. Their complex (the "Microprocessor") is essential for processing of long, primary microRNAs (pri-miRNAs) in the nucleus. Binding of heme to DGCR8 is essential for pri-miRNA processing. On the basis of the split Soret ultraviolet-visible (UV-vis) spectrum of ferric DGCR8, bis-thiolate sulfur (cysteinate, Cys(-)) heme iron coordination of DGCR8 heme iron was proposed. We have characterized DGCR8 heme ligation using the Δ276 DGCR8 variant and combined electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), electron nuclear double resonance, resonance Raman, and electronic absorption spectroscopy. These studies indicate DGCR8 bis-Cys heme iron ligation, with conversion from bis-thiolate (Cys(-)/Cys(-)) axial coordination in ferric DGCR8 to bis-thiol (CysH/CysH) coordination in ferrous DGCR8. Pri-miRNA binding does not perturb ferric DGCR8's optical spectrum, consistent with the axial ligand environment being separated from the substrate-binding site. UV-vis absorption spectra of the Fe(II) and Fe(II)-CO forms indicate discrete species exhibiting peaks with absorption coefficients substantially larger than those for ferric DGCR8 and that previously reported for a ferrous form of DGCR8. Electron-nuclear double resonance spectroscopy data exclude histidine or water as axial ligands for ferric DGCR8 and favor bis-thiolate coordination in this form. UV-vis MCD and near-infrared MCD provide data consistent with this conclusion. UV-vis MCD data for ferrous DGCR8 reveal features consistent with bis-thiol heme iron coordination, and resonance Raman data for the ferrous-CO form are consistent with a thiol ligand trans to the CO. These studies support retention of DGCR8 cysteine coordination upon reduction, a conclusion distinct from those of previous studies of a different ferrous DGCR8 isoform.

  18. A subset of group A-like var genes encodes the malaria parasite ligands for binding to human brain endothelial cells

    DEFF Research Database (Denmark)

    Claessens, Antoine; Adams, Yvonne; Ghumra, Ashfaq


    of these variants. The clinical in vivo relevance of the HBEC-selected parasites was supported by significantly higher surface recognition of HBEC-selected parasites compared with unselected parasites by antibodies from young African children suffering cerebral malaria (Mann-Whitney test, P = 0...

  19. UK malaria treatment guidelines 2016. (United States)

    Lalloo, David G; Shingadia, Delane; Bell, David J; Beeching, Nicholas J; Whitty, Christopher J M; Chiodini, Peter L


    1.Malaria is the tropical disease most commonly imported into the UK, with 1300-1800 cases reported each year, and 2-11 deaths. 2. Approximately three quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. 3. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other species of plasmodium: Plasmodium ovale, Plasmodium malariae or Plasmodium knowlesi. 4. Mixed infections with more than one species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. 5. There are no typical clinical features of malaria; even fever is not invariably present. Malaria in children (and sometimes in adults) may present with misleading symptoms such as gastrointestinal features, sore throat or lower respiratory complaints. 6. A diagnosis of malaria must always be sought in a feverish or sick child or adult who has visited malaria-endemic areas. Specific country information on malaria can be found at P. falciparum infection rarely presents more than six months after exposure but presentation of other species can occur more than a year after exposure. 7. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until more than one blood specimen has been examined. Other travel related infections, especially viral haemorrhagic fevers, should also be considered. 8. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites. P. falciparum and P. vivax (depending upon the product) malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens. RDTs for other Plasmodium species are not as reliable. 9

  20. Malaria in India: Challenges and opportunities

    Indian Academy of Sciences (India)

    A P Dash; Neena Valecha; A R Anvikar; A Kumar


    India contributes about 70% of malaria in the South East Asian Region of WHO. Although annually India reports about two million cases and 1000 deaths attributable to malaria, there is an increasing trend in the proportion of Plasmodium falciparum as the agent. There exists heterogeneity and variability in the risk of malaria transmission between and within the states of the country as many ecotypes/paradigms of malaria have been recognized. The pattern of clinical presentation of severe malaria has also changed and while multi-organ failure is more frequently observed in falciparum malaria, there are reports of vivax malaria presenting with severe manifestations. The high burden populations are ethnic tribes living in the forested pockets of the states like Orissa, Jharkhand, Madhya Pradesh, Chhattisgarh and the North Eastern states which contribute bulk of morbidity and mortality due to malaria in the country. Drug resistance, insecticide resistance, lack of knowledge of actual disease burden along with new paradigms of malaria pose a challenge for malaria control in the country. Considering the existing gaps in reported and estimated morbidity and mortality, need for estimation of true burden of malaria has been stressed. Administrative, financial, technical and operational challenges faced by the national programme have been elucidated. Approaches and priorities that may be helpful in tackling serious issues confronting malaria programme have been outlined.

  1. Malaria transmission rates estimated from serological data.


    Burattini, M. N.; Massad, E; Coutinho, F. A.


    A mathematical model was used to estimate malaria transmission rates based on serological data. The model is minimally stochastic and assumes an age-dependent force of infection for malaria. The transmission rates estimated were applied to a simple compartmental model in order to mimic the malaria transmission. The model has shown a good retrieving capacity for serological and parasite prevalence data.

  2. Towards malaria elimination - a new thematic series

    Directory of Open Access Journals (Sweden)

    Tanner Marcel


    Full Text Available Abstract The launch of a new thematic series of Malaria Journal -- "Towards malaria elimination" -- creates the forum that allows carrying scientific evidence on how to achieve malaria elimination in specific endemic settings and conditions into the circles of scientists, public health specialists, national and global programme managers, funders and decision makers.

  3. Gene-therapy for malaria prevention. (United States)

    Rodrigues, Mauricio M; Soares, Irene S


    The limited number of tools for malaria prevention and the inability to eradicate the disease have required large investments in vaccine development, as vaccines have been the only foreseeable type of immunoprophylaxis against malaria. An alternative strategy named vectored immunoprophylaxis (VIP) now would allow genetically transduced host cells to assemble and secrete antibodies that neutralize the infectivity of the malaria parasite and prevent disease.

  4. Changing malaria transmission and implications in China towards National Malaria Elimination Programme between 2010 and 2012.

    Directory of Open Access Journals (Sweden)

    Jian-hai Yin

    Full Text Available BACKGROUND: Towards the implementation of national malaria elimination programme in China since 2010, the epidemiology of malaria has changed dramatically, and the lowest malaria burden was achieved yearly. It is time to analyze the changes of malaria situation based on surveillance data from 2010 to 2012 to reconsider the strategies for malaria elimination. METHODS AND PRINCIPAL FINDINGS: Malaria epidemiological data was extracted from the provincial annual reports in China between 2010 and 2012. The trends of the general, autochthonous and imported malaria were analyzed, and epidemic areas were reclassified according to Action Plan of China Malaria Elimination (2010-2020. As a result, there reported 2743 malaria cases with a continued decline in 2012, and around 7% autochthonous malaria cases accounted. Three hundred and fifty-three individual counties from 19 provincial regions had autochthonous malaria between 2010 and 2012, and only one county was reclassified into Type I (local infections detected in 3 consecutive years and the annual incidences ≥ 1/10,000 again. However, the imported malaria cases reported of each year were widespread, and 598 counties in 29 provinces were suffered in 2012. CONCLUSIONS/SIGNIFICANCE: Malaria was reduced significantly from 2010 to 2012 in China, and malaria importation became an increasing challenge. It is necessary to adjust or update the interventions for subsequent malaria elimination planning and resource allocation.

  5. Averting a malaria disaster: will insecticide resistance derail malaria control? (United States)

    Hemingway, Janet; Ranson, Hilary; Magill, Alan; Kolaczinski, Jan; Fornadel, Christen; Gimnig, John; Coetzee, Maureen; Simard, Frederic; Roch, Dabiré K; Hinzoumbe, Clément Kerah; Pickett, John; Schellenberg, David; Gething, Peter; Hoppé, Mark; Hamon, Nicholas


    World Malaria Day 2015 highlighted the progress made in the development of new methods of prevention (vaccines and insecticides) and treatment (single dose drugs) of the disease. However, increasing drug and insecticide resistance threatens the successes made with existing methods. Insecticide resistance has decreased the efficacy of the most commonly used insecticide class of pyrethroids. This decreased efficacy has increased mosquito survival, which is a prelude to rising incidence of malaria and fatalities. Despite intensive research efforts, new insecticides will not reach the market for at least 5 years. Elimination of malaria is not possible without effective mosquito control. Therefore, to combat the threat of resistance, key stakeholders need to rapidly embrace a multifaceted approach including a reduction in the cost of bringing new resistance management methods to market and the streamlining of associated development, policy, and implementation pathways to counter this looming public health catastrophe.

  6. Nitric oxide bioavailability in malaria. (United States)

    Sobolewski, Peter; Gramaglia, Irene; Frangos, John; Intaglietta, Marcos; van der Heyde, Henri C


    Rational development of adjunct or anti-disease therapy for severe Plasmodium falciparum malaria requires cellular and molecular definition of malarial pathogenesis. Nitric oxide (NO) is a potential target for such therapy but its role during malaria is controversial. It has been proposed that NO is produced at high levels to kill Plasmodium parasites, although the unfortunate consequence of elevated NO levels might be impaired neuronal signaling, oxidant damage and red blood cell damage that leads to anemia. In this case, inhibitors of NO production or NO scavengers might be an effective adjunct therapy. However, increasing amounts of evidence support the alternate hypothesis that NO production is limited during malaria. Furthermore, the well-documented NO scavenging by cell-free plasma hemoglobin and superoxide, the levels of which are elevated during malaria, has not been considered. Low NO bioavailability in the vasculature during malaria might contribute to pathologic activation of the immune system, the endothelium and the coagulation system: factors required for malarial pathogenesis. Therefore, restoring NO bioavailability might represent an effective anti-disease therapy.


    Directory of Open Access Journals (Sweden)



    Full Text Available OBJECTIVE: Malarial infection is a major health problem in many parts of India. Several factors have been attributed to increased morbidity and mortality in malaria with altered hematological and hepatic parameters playing an important role. Our aim is to study the clinical, hematological and hepatic manifestations in patients with falciparum malaria. METHODS: This observational study was conducted from November 2012 to October 2013 at Kempegowda Institute of Medical Science and Research Hospital Bangalore. 75 patients of falciparum malaria confirmed by PS, MPQBC positive for Plasmodium falciparum or both falciparum and vivax were included in the study. All patients underwent detailed clinical history, thorough physical examination and investigated with hematological and hepatic parameters. This was followed by monitoring the outcome of the patients with respect to morbidity and mortality. Data was analyzed with descriptive statistical tools. RESULT: Of the 75 patients fever was present in all cases. Pallor (62% was the most common sign followed by splenomegaly (58% and icterus (48%. Anemia (60% was the most common complication, followed by jaundice (44%, cerebral malaria (40%, ARF (25%, ARDS (12%. 12 patients had severe anemia (Hb% <6 gm %. Severe thrombocytopenia (<50, 000 mm3 was seen in 5% of the patients. PT and APTT were increased in 23% and 12% of the cases respectively. 2 patients in the study expired. CONCLUSION: Clinical manifestations of plasmodium falciparum infection ranged from only fever to severe complications including cerebral malaria, acute renal failure, acute hemolytic crisis and hepatic dysfunction. Acute onset fever and splenomegaly were most common clinical manifestations found. Severe Anemia and jaundice are poor prognostic factor and has adverse outcome. Thrombocytopenia increased PT; aPTT does not have any correlation to mortality

  8. Heme oxygenase-1 and carbon monoxide in pulmonary medicine. (United States)

    Slebos, Dirk-Jan; Ryter, Stefan W; Choi, Augustine M K


    Heme oxygenase-1 (HO-1), an inducible stress protein, confers cytoprotection against oxidative stress in vitro and in vivo. In addition to its physiological role in heme degradation, HO-1 may influence a number of cellular processes, including growth, inflammation, and apoptosis. By virtue of anti-inflammatory effects, HO-1 limits tissue damage in response to proinflammatory stimuli and prevents allograft rejection after transplantation. The transcriptional upregulation of HO-1 responds to many agents, such as hypoxia, bacterial lipopolysaccharide, and reactive oxygen/nitrogen species. HO-1 and its constitutively expressed isozyme, heme oxygenase-2, catalyze the rate-limiting step in the conversion of heme to its metabolites, bilirubin IXalpha, ferrous iron, and carbon monoxide (CO). The mechanisms by which HO-1 provides protection most likely involve its enzymatic reaction products. Remarkably, administration of CO at low concentrations can substitute for HO-1 with respect to anti-inflammatory and anti-apoptotic effects, suggesting a role for CO as a key mediator of HO-1 function. Chronic, low-level, exogenous exposure to CO from cigarette smoking contributes to the importance of CO in pulmonary medicine. The implications of the HO-1/CO system in pulmonary diseases will be discussed in this review, with an emphasis on inflammatory states.

  9. Heme oxygenase-1 and carbon monoxide in pulmonary medicine

    Directory of Open Access Journals (Sweden)

    Choi Augustine MK


    Full Text Available Abstract Heme oxygenase-1 (HO-1, an inducible stress protein, confers cytoprotection against oxidative stress in vitro and in vivo. In addition to its physiological role in heme degradation, HO-1 may influence a number of cellular processes, including growth, inflammation, and apoptosis. By virtue of anti-inflammatory effects, HO-1 limits tissue damage in response to proinflammatory stimuli and prevents allograft rejection after transplantation. The transcriptional upregulation of HO-1 responds to many agents, such as hypoxia, bacterial lipopolysaccharide, and reactive oxygen/nitrogen species. HO-1 and its constitutively expressed isozyme, heme oxygenase-2, catalyze the rate-limiting step in the conversion of heme to its metabolites, bilirubin IXα, ferrous iron, and carbon monoxide (CO. The mechanisms by which HO-1 provides protection most likely involve its enzymatic reaction products. Remarkably, administration of CO at low concentrations can substitute for HO-1 with respect to anti-inflammatory and anti-apoptotic effects, suggesting a role for CO as a key mediator of HO-1 function. Chronic, low-level, exogenous exposure to CO from cigarette smoking contributes to the importance of CO in pulmonary medicine. The implications of the HO-1/CO system in pulmonary diseases will be discussed in this review, with an emphasis on inflammatory states.

  10. Heme and menaquinone induced electron transport in lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.; Smit, B.; Santos, dos F.; Riel, van J.; Vos, de W.M.; Hugenholtz, J.


    ABSTRACT: BACKGROUND: For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. RES

  11. Heme and HO-1 inhibition of HCV, HBV, and HIV

    Directory of Open Access Journals (Sweden)

    Warren N Schmidt


    Full Text Available Hepatitis C virus, human immunodeficiency virus, and hepatitis B virus are chronic viral infections that cause considerable morbidity and mortality throughout the world. In the decades following the identification and sequencing of these viruses, in vitro experiments demonstrated that heme oxygenase-1, its oxidative products, and related compounds of the heme oxygenase system are virucidal for all three viruses. The purpose of this review is to critically evaluate and summarize the seminal studies that described and characterized this remarkable behavior. It will also discuss more recent work that discovered the antiviral mechanisms and target sites of these unique antiviral agents. In spite of the fact that these viruses are diverse pathogens with quite profound differences in structure and life cycle, it is significant that heme and related compounds show striking similarity for viral target sites across all three species. Collectively, these findings strongly indicate that we should move forward and develop heme and related tetrapyrroles into versatile antiviral agents that could be used therapeutically in patients with single or multiple viral infections.

  12. The Heme Connection: Linking Erythrocytes and Macrophage Biology (United States)

    Alam, Md Zahidul; Devalaraja, Samir; Haldar, Malay


    Erythroid function and development is intimately linked to macrophages. The primary function of erythrocytes is oxygen delivery, which is mediated by iron-containing hemoglobin. The major source of this iron is a recycling pathway where macrophages scavenge old and damaged erythrocytes to release iron contained within the heme moiety. Macrophages also promote erythropoiesis by providing a supportive niche in the bone marrow as an integral component of “erythorblastic islands.” Importantly, inflammation leads to alterations in iron handling by macrophages with significant impact on iron homeostasis and erythropoiesis. The importance of macrophages in erythropoiesis and iron homeostasis is well established and has been extensively reviewed. However, this developmental relationship is not one way, and erythrocytes can also regulate macrophage development and function. Erythrocyte-derived heme can induce the development of iron-recycling macrophages from monocytes, engage pattern recognition receptors to activate macrophages, and act as ligand for specific nuclear receptors to modulate macrophage function. Here, we discuss the role of heme as a signaling molecule impacting macrophage homeostasis. We will review these actions of heme within the framework of our current understanding of the role of micro-environmental factors in macrophage development and function. PMID:28167947

  13. Mechanism of reaction of chlorite with mammalian heme peroxidases. (United States)

    Jakopitsch, Christa; Pirker, Katharina F; Flemmig, Jörg; Hofbauer, Stefan; Schlorke, Denise; Furtmüller, Paul G; Arnhold, Jürgen; Obinger, Christian


    This study demonstrates that heme peroxidases from different superfamilies react differently with chlorite. In contrast to plant peroxidases, like horseradish peroxidase (HRP), the mammalian counterparts myeloperoxidase (MPO) and lactoperoxidase (LPO) are rapidly and irreversibly inactivated by chlorite in the micromolar concentration range. Chlorite acts as efficient one-electron donor for Compound I and Compound II of MPO and LPO and reacts with the corresponding ferric resting states in a biphasic manner. The first (rapid) phase is shown to correspond to the formation of a MPO-chlorite high-spin complex, whereas during the second (slower) phase degradation of the prosthetic group was observed. Cyanide, chloride and hydrogen peroxide can block or delay heme bleaching. In contrast to HRP, the MPO/chlorite system does not mediate chlorination of target molecules. Irreversible inactivation is shown to include heme degradation, iron release and decrease in thermal stability. Differences between mammalian peroxidases and HRP are discussed with respect to differences in active site architecture and heme modification.

  14. Structural and spectroscopic characterisation of a heme peroxidase from sorghum. (United States)

    Nnamchi, Chukwudi I; Parkin, Gary; Efimov, Igor; Basran, Jaswir; Kwon, Hanna; Svistunenko, Dimitri A; Agirre, Jon; Okolo, Bartholomew N; Moneke, Anene; Nwanguma, Bennett C; Moody, Peter C E; Raven, Emma L


    A cationic class III peroxidase from Sorghum bicolor was purified to homogeneity. The enzyme contains a high-spin heme, as evidenced by UV-visible spectroscopy and EPR. Steady state oxidation of guaiacol was demonstrated and the enzyme was shown to have higher activity in the presence of calcium ions. A Fe(III)/Fe(II) reduction potential of -266 mV vs NHE was determined. Stopped-flow experiments with H2O2 showed formation of a typical peroxidase Compound I species, which converts to Compound II in the presence of calcium. A crystal structure of the enzyme is reported, the first for a sorghum peroxidase. The structure reveals an active site that is analogous to those for other class I heme peroxidase, and a substrate binding site (assigned as arising from binding of indole-3-acetic acid) at the γ-heme edge. Metal binding sites are observed in the structure on the distal (assigned as a Na(+) ion) and proximal (assigned as a Ca(2+)) sides of the heme, which is consistent with the Ca(2+)-dependence of the steady state and pre-steady state kinetics. It is probably the case that the structural integrity (and, thus, the catalytic activity) of the sorghum enzyme is dependent on metal ion incorporation at these positions.

  15. Heme oxygenase-1/carbon monoxide: from metabolism to molecular therapy. (United States)

    Ryter, Stefan W; Choi, Augustine M K


    Heme oxygenase-1 (HO-1), a ubiquitous inducible stress-response protein, serves a major metabolic function in heme turnover. HO activity cleaves heme to form biliverdin-IXalpha, carbon monoxide (CO), and iron. Genetic experiments have revealed a central role for HO-1 in tissue homeostasis, protection against oxidative stress, and in the pathogenesis of disease. Four decades of research have witnessed not only progress in elucidating the molecular mechanisms underlying the regulation and function of this illustrious enzyme, but also have opened remarkable translational applications for HO-1 and its reaction products. CO, once regarded as a metabolic waste, can act as an endogenous mediator of cellular signaling and vascular function. Exogenous application of CO by inhalation or pharmacologic delivery can confer cytoprotection in preclinical models of lung/vascular injury and disease, based on anti-apoptotic, anti-inflammatory, and anti-proliferative properties. The bile pigments, biliverdin and bilirubin, end products of heme degradation, have also shown potential as therapeutics in vascular disease based on anti-inflammatory and anti-proliferative activities. Further translational and clinical trials research will unveil whether the HO-1 system or any of its reaction products can be successfully applied as molecular medicine in human disease.

  16. Degradation of Heme in Gram-Negative Bacteria: the Product of the hemO Gene of Neisseriae Is a Heme Oxygenase



    A full-length heme oxygenase gene from the gram-negative pathogen Neisseria meningitidis was cloned and expressed in Escherichia coli. Expression of the enzyme yielded soluble catalytically active protein and caused accumulation of biliverdin within the E. coli cells. The purified HemO forms a 1:1 complex with heme and has a heme protein spectrum similar to that previously reported for the purified heme oxygenase (HmuO) from the gram-positive pathogen Corynebacterium diphtheriae and for eukar...

  17. Mechanism of horseradish peroxidase-catalyzed heme oxidation and polymerization (beta-hematin formation). (United States)

    Trivedi, Vishal; Chand, Prem; Maulik, Prakas R; Bandyopadhyay, Uday


    Horseradish peroxidase (HRP) catalyzes the polymerization of free heme (beta-hematin formation) through its oxidation. Heme when added to HRP compound II (FeIV=O) causes spectral shift from 417 nm (Compound II) to 402 nm (native, FeIII) indicating that heme may be oxidized via one-electron transfer. Direct evidence for one-electron oxidation of heme by HRP intermediates is provided by the appearance of an E.s.r signal of a 5,5-dimethyl-1-pyrroline N-oxide (spin trap)-heme radical adduct (a1H=14.75 G, a2H=4.0 G) in E.s.r studies. Heme-polymerization by HRP is inhibited by spin trap indicating that one-electron oxidation product of heme ultimately leads to the formation of heme-polymer. HRP, when incubated with diethyl pyrocarbonate (DEPC), a histidine specific reagent, shows concentration dependent loss of heme-polymerization indicating the role of histidine residues in the process. We suggest that HRP catalyzes the formation of heme-polymer through one-electron oxidation of free heme.

  18. Haemoproteus and Schistosoma synthesize heme polymers similar to Plasmodium hemozoin and beta-hematin. (United States)

    Chen, M M; Shi, L; Sullivan, D J


    Many parasites digest hemoglobin as an amino acid source, but only a few produce heme polymer pigment instead of catabolizing heme via heme oxygenase. This work compares purified heme polymers produced by Haemoproteus columbae and Schistosoma mansoni to that of Plasmodium falciparum hemozoin and synthetic beta-hematin. Fourier-transform infrared spectroscopy identifies the signature peaks of the common iron-carboxylate bond characteristic in all four heme polymers. However, all pigments could be distinguished by quite different three-dimensional structure visualized by Field Emission Inlens Scanning Electron Microscopy. Both P. falciparum and H. columbae heme polymers had a symmetrical shape unlike the amorphous S. mansoni heme polymer and beta-hematin. All four heme pigments serve as templates for heme polymer extension, which was inhibitable by chloroquine and other quinoline antimalarials. The polymers showed different levels of resistance to hydrogen peroxide degradation. This work identifies another genus, Haemoproteus, capable of intracellular heme polymer formation. The different three-dimensional structures of each pigment implicate genus specific formation of heme polymer, variation of inhibition of polymer extension by the quinolines and degradation by hydrogen peroxide.

  19. Identification and characterization of a heme periplasmic-binding protein in Haemophilus ducreyi. (United States)

    St Denis, Melissa; Sonier, Brigitte; Robinson, Renée; Scott, Fraser W; Cameron, D William; Lee, B Craig


    Haemophilus ducreyi, a gram-negative and heme-dependent bacterium, is the causative agent of chancroid, a genital ulcer sexually transmitted infection. Heme acquisition in H. ducreyi proceeds via a receptor mediated process in which the initial event involves binding of hemoglobin and heme to their cognate outer membrane proteins, HgbA and TdhA, respectively. Following this specific interaction, the fate of the periplasmic deposited heme is unclear. Using protein expression profiling of the H. ducreyi periplasmic proteome, a periplasmic-binding protein, termed hHbp, was identified whose expression was enhanced under heme-limited conditions. The gene encoding this protein was situated in a locus displaying genetic characteristics of an ABC transporter. The purified protein bound heme in a dose-dependent and saturable manner and this binding was specifically competitively inhibited by heme. The hhbp gene functionally complemented an Escherichia coli heme uptake mutant. Expression of the heme periplasmic-binding protein was detected in a limited survey of H. ducreyi and H. influenzae clinical strains. These results indicate that the passage of heme into the cytoplasm of H. ducreyi involves a heme dedicated ABC transporter.

  20. Structural basis of heme binding in the Cu,Zn superoxide dismutase from Haemophilus ducreyi. (United States)

    Töro, Imre; Petrutz, Cristiana; Pacello, Francesca; D'Orazio, Melania; Battistoni, Andrea; Djinović-Carugo, Kristina


    The Cu,Zn superoxide dismutase from Haemophilus ducreyi is characterized by the unique ability to bind heme at its dimer interface. Here we report the high-resolution crystal structures of this protein in the heme-loaded (holo) and heme-free (apo) forms. Heme is asymmetrically bound between the two enzyme subunits, where heme iron is coordinated by two histidine residues, His64 and His 124, provided by the two subunits. Moreover, the binding of heme to the protein is ensured by stabilizing contacts between the prosthetic group and a limited number of other residues, most of which are not present in other bacterial enzyme variants. We show that the introduction of only three mutations at the dimer interface of the enzyme from Haemophilus parainfluenzae, a closely related bacterial species, is sufficient to induce heme-binding ability by this enzyme variant. Heme binding does not alter protein activity. Moreover, the binding of the prosthetic group does not induce any significant structural perturbation at the subunit level and requires only limited local structural rearrangements that widen the cleft at the dimer interface and cause a limited shift in the relative orientation between the subunits. The presence of a preformed heme-binding pocket and the significant solvent exposure of the cofactor to the solvent are compatible with the suggested protective role of the enzyme against heme toxicity or with its involvement in heme trafficking in the periplasmic space.

  1. Regulatory Fe(II/III) heme: the reconstruction of a molecule's biography. (United States)

    Kühl, Toni; Imhof, Diana


    More than 20 years of research on heme as a temporary effector molecule of proteins have revealed its widespread impact on virtually all primary functions in the human organism. As our understanding of this influence is still growing, a comprehensive overview of compiled data will give fresh impetus for creativity and developing new strategies in heme-related research. From known data concerning heme-regulated proteins and their involvement in the development of diseases, we provide concise information of Fe(II/III) heme as a regulator and the availability of "regulatory heme". The latter is dependent on the balance between free and bound Fe(II/III) heme, here termed "hemeostasis". Imbalance of this system can lead to the development of diseases that were not always attributed to this small molecule. Diseases such as cancer or Alzheimer's disease highlight the reawakened interest in heme, whose function was previously believed to be completely understood.

  2. Cutaneous findings in five cases of malaria

    Directory of Open Access Journals (Sweden)

    Jignesh B Vaishnani


    Full Text Available Malaria is an infectious disease caused by protozoa of the genus Plasmodium. Cutaneous lesions in malaria are rarely reported and include urticaria, angioedema, petechiae, purpura, and disseminated intravascular coagulation (DIC. Here, five malaria cases associated with cutaneous lesions have been described. Out of the five cases of malaria, two were associated with urticaria and angioedema, one case was associated with urticaria, and other two were associated with reticulated blotchy erythema with petechiae. Most of the cutaneous lesions in malaria were nonspecific and reflected the different immunopathological mechanism in malarial infection.

  3. Protein C system defects inflicted by the malaria parasite protein PfEMP1 can be overcome by a soluble EPCR variant

    DEFF Research Database (Denmark)

    Petersen, Jens E V; Bouwens, Eveline A M; Tamayo, Ibai;


    The Endothelial Protein C receptor (EPCR) is essential for the anticoagulant and cytoprotective functions of the Protein C (PC) system. Selected variants of the malaria parasite protein, Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) associated with severe malaria, including cerebral...... malaria, specifically target EPCR on vascular endothelial cells. Here, we examine the cellular response to PfEMP1 engagement to elucidate its role in malaria pathogenesis. Binding of the CIDRα1.1 domain of PfEMP1 to EPCR obstructed activated PC (APC) binding to EPCR and induced a loss of cellular EPCR...... not interfere with (A)PC binding to cellular EPCR. E86A-sEPCR used as a decoy to capture PfEMP1, permitted normal PC activation on endothelial cells, normal barrier protective effects of APC, and greatly reduced cytoadhesion of infected erythrocytes to brain endothelial cells. These data imply important...


    Directory of Open Access Journals (Sweden)

    Alessandro Bartoloni


    Full Text Available The first symptoms of malaria, common to all the different malaria species, are nonspecific and mimic a flu-like syndrome. Although fever represents the cardinal feature, clinical findings in malaria are extremely diverse and may range in severity from mild headache to serious complications leading to death, particularly in falciparum malaria. As the progression to these complications can be rapid, any malaria patient must be assessed and treated rapidly, and frequent observations are needed to look for early signs of systemic complications. In fact, severe malaria is a life threatening but treatable disease.  The protean and nonspecific clinical findings occurring in malaria (fever, malaise, headache, myalgias, jaundice and sometimes gastrointestinal symptoms of nausea, vomiting and diarrhoea may lead physicians who see malaria infrequently to a wrong diagnosis, such as influenza (particularly during the seasonal epidemic flu, dengue, gastroenteritis, typhoid fever, viral hepatitis, encephalitis. Physicians should be aware that malaria is not a clinical diagnosis but must be diagnosed, or excluded, by performing microscopic examination of blood films. Prompt diagnosis and appropriate treatment are then crucial to prevent morbidity and fatal outcomes. Although Plasmodium falciparum malaria is the major cause of severe malaria and death, increasing evidence has recently emerged that Plasmodium vivax and Plasmodium knowlesi can also be severe and even fatal.

  5. Plasmodium vivax malaria: An unusual presentation

    Directory of Open Access Journals (Sweden)

    Kasliwal Prasad


    Full Text Available Acute renal failure, disseminated intravascular coagulation (DIC, acute respiratory distress syndrome (ARDS, hypoglycemia, coma, or epileptic seizures are manifestations of severe Plasmodium falciparum malaria. On the other hand, Plasmodium vivax malaria seldom results in pulmonary damage, and pulmonary complications are exceedingly rare. We report the case of a 42-year-old male living in a malaria-endemic area who presented with ARDS and was diagnosed as having Plasmodium vivax malaria. A diagnosis of Plasmodium vivax malaria was established by a positive Plasmodium LDH immunochromatographic assay while a negative PfHRP2 based assay ruled out P. falciparum malaria. After specific anti-plasmodial therapy and intensive supportive care, the patient recovered and was discharged from hospital. The use of NIPPV in vivax-malaria related ARDS was associated with a good outcome.

  6. Dietary heme-mediated PPARa activation does not affect the heme-induced epithelial hyperproliferation and hyperplasia in mouse colon

    NARCIS (Netherlands)

    IJssenagger, N.; Wit, de N.J.W.; Muller, M.R.; Meer, van der R.


    Red meat consumption is associated with an increased colon cancer risk. Heme, present in red meat, injures the colon surface epithelium by luminal cytotoxicity and reactive oxygen species. This surface injury is overcompensated by hyperproliferation and hyperplasia of crypt cells. Transcriptome anal

  7. Parasite burden and CD36-mediated sequestration are determinants of acute lung injury in an experimental malaria model.

    Directory of Open Access Journals (Sweden)

    Fiona E Lovegrove


    Full Text Available Although acute lung injury (ALI is a common complication of severe malaria, little is known about the underlying molecular basis of lung dysfunction. Animal models have provided powerful insights into the pathogenesis of severe malaria syndromes such as cerebral malaria (CM; however, no model of malaria-induced lung injury has been definitively established. This study used bronchoalveolar lavage (BAL, histopathology and gene expression analysis to examine the development of ALI in mice infected with Plasmodium berghei ANKA (PbA. BAL fluid of PbA-infected C57BL/6 mice revealed a significant increase in IgM and total protein prior to the development of CM, indicating disruption of the alveolar-capillary membrane barrier-the physiological hallmark of ALI. In contrast to sepsis-induced ALI, BAL fluid cell counts remained constant with no infiltration of neutrophils. Histopathology showed septal inflammation without cellular transmigration into the alveolar spaces. Microarray analysis of lung tissue from PbA-infected mice identified a significant up-regulation of expressed genes associated with the gene ontology categories of defense and immune response. Severity of malaria-induced ALI varied in a panel of inbred mouse strains, and development of ALI correlated with peripheral parasite burden but not CM susceptibility. Cd36(-/- mice, which have decreased parasite lung sequestration, were relatively protected from ALI. In summary, parasite burden and CD36-mediated sequestration in the lung are primary determinants of ALI in experimental murine malaria. Furthermore, differential susceptibility of mouse strains to malaria-induced ALI and CM suggests that distinct genetic determinants may regulate susceptibility to these two important causes of malaria-associated morbidity and mortality.

  8. Severe malaria - a case of fatal Plasmodium knowlesi infection with post-mortem findings: a case report

    Directory of Open Access Journals (Sweden)

    Adem Patricia


    Full Text Available Abstract Background Zoonotic malaria caused by Plasmodium knowlesi is an important, but newly recognized, human pathogen. For the first time, post-mortem findings from a fatal case of knowlesi malaria are reported here. Case presentation A formerly healthy 40 year-old male became symptomatic 10 days after spending time in the jungle of North Borneo. Four days later, he presented to hospital in a state of collapse and died within two hours. He was hyponatraemic and had elevated blood urea, potassium, lactate dehydrogenase and amino transferase values; he was also thrombocytopenic and eosinophilic. Dengue haemorrhagic shock was suspected and a post-mortem examination performed. Investigations for dengue virus were negative. Blood for malaria parasites indicated hyperparasitaemia and single species P. knowlesi infection was confirmed by nested-PCR. Macroscopic pathology of the brain and endocardium showed multiple petechial haemorrhages, the liver and spleen were enlarged and lungs had features consistent with ARDS. Microscopic pathology showed sequestration of pigmented parasitized red blood cells in the vessels of the cerebrum, cerebellum, heart and kidney without evidence of chronic inflammatory reaction in the brain or any other organ examined. Brain sections were negative for intracellular adhesion molecule-1. The spleen and liver had abundant pigment containing macrophages and parasitized red blood cells. The kidney had evidence of acute tubular necrosis and endothelial cells in heart sections were prominent. Conclusions The overall picture in this case was one of systemic malaria infection that fit the WHO classification for severe malaria. Post-mortem findings in this case were unexpectedly similar to those that define fatal falciparum malaria, including cerebral pathology. There were important differences including the absence of coma despite petechial haemorrhages and parasite sequestration in the brain. These results suggest that further

  9. Perivascular iron deposits are associated with protein nitration in cerebral experimental autoimmune encephalomyelitis. (United States)

    Sands, Scott A; Williams, Rachel; Marshall, Sylvester; LeVine, Steven M


    Nitration of proteins, which is thought to be mediated by peroxynitrite, is a mechanism of tissue damage in multiple sclerosis (MS). However, protein nitration can also be catalyzed by iron, heme or heme-associated molecules independent of peroxynitrite. Since microhemorrhages and perivascular iron deposits are present in the CNS of MS patients, we sought to determine if iron is associated with protein nitration. A cerebral model of experimental autoimmune encephalomyelitis (cEAE) was utilized since this model has been shown to have perivascular iron deposits similar to those present in MS. Histochemical staining for iron was used together with immunohistochemistry for nitrotyrosine, eNOS, or iNOS on cerebral sections. Leakage of the blood-brain barrier (BBB) was studied by albumin immunohistochemistry. Iron deposits were colocalized with nitrotyrosine staining around vessels in cEAE mice while control animals revealed minimal staining. This finding supports the likelihood that nitrotyrosine formation was catalyzed by iron or iron containing molecules. Examples of iron deposits were also observed in association with eNOS and iNOS, which could be one source of substrates for this reaction. Extravasation of albumin was present in cEAE mice, but not in control animals. Extravasated albumin may act to limit tissue injury by binding iron and/or heme as well as being a target of nitration, but the protection is incomplete. In summary, iron-catalyzed nitration of proteins is a likely mechanism of tissue damage in MS.

  10. Malaria successes and challenges in Asia. (United States)

    Bhatia, Rajesh; Rastogi, Rakesh Mani; Ortega, Leonard


    Asia ranks second to Africa in terms of malaria burden. In 19 countries of Asia, malaria is endemic and 2.31 billion people or 62% of the total population in these countries are at risk of malaria. In 2010, WHO estimated around 34.8 million cases and 45,600 deaths due to malaria in Asia. In 2011, 2.7 million cases and > 2000 deaths were reported. India, Indonesia, Myanmar and Pakistan are responsible for >85% of the reported cases (confirmed) and deaths in Asia. In last 10 yr, due to availability of donor's fund specially from Global fund, significant progress has been made by the countries in Asia in scaling-up malaria control interventions which were instrumental in reducing malaria morbidity and mortality significantly. There is a large heterogeneity in malaria epidemiology in Asia. As a result, the success in malaria control/elimination is also diverse. As compared to the data of the year 2000, out of 19 malaria endemic countries, 12 countries were able to reduce malaria incidence (microscopically confirmed cases only) by 75%. Two countries, namely Bangladesh and Malaysia are projected to reach 75% reduction by 2015 while India is projected to reach 50-75% only by 2015. The trend could not be assessed in four countries, namely Indonesia, Myanmar, Pakistan and Timor-Leste due to insufficient consistent data. Numerous key challenges need to be addressed to sustain the gains and eliminate malaria in most parts of Asia. Some of these are to control the spread of resistance in Plasmodium falciparum to artemisinin, control of outdoor transmission, control of vivax malaria and ensuring universal coverage of key interventions. Asia has the potential to influence the malaria epidemiology all over the world as well as to support the global efforts in controlling and eliminating malaria through production of quality-assured ACTs, RDTs and long-lasting insecticidal nets.

  11. An open source business model for malaria.

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    Christine Årdal

    Full Text Available Greater investment is required in developing new drugs and vaccines against malaria in order to eradicate malaria. These precious funds must be carefully managed to achieve the greatest impact. We evaluate existing efforts to discover and develop new drugs and vaccines for malaria to determine how best malaria R&D can benefit from an enhanced open source approach and how such a business model may operate. We assess research articles, patents, clinical trials and conducted a smaller survey among malaria researchers. Our results demonstrate that the public and philanthropic sectors are financing and performing the majority of malaria drug/vaccine discovery and development, but are then restricting access through patents, 'closed' publications and hidden away physical specimens. This makes little sense since it is also the public and philanthropic sector that purchases the drugs and vaccines. We recommend that a more "open source" approach is taken by making the entire value chain more efficient through greater transparency which may lead to more extensive collaborations. This can, for example, be achieved by empowering an existing organization like the Medicines for Malaria Venture (MMV to act as a clearing house for malaria-related data. The malaria researchers that we surveyed indicated that they would utilize such registry data to increase collaboration. Finally, we question the utility of publicly or philanthropically funded patents for malaria medicines, where little to no profits are available. Malaria R&D benefits from a publicly and philanthropically funded architecture, which starts with academic research institutions, product development partnerships, commercialization assistance through UNITAID and finally procurement through mechanisms like The Global Fund to Fight AIDS, Tuberculosis and Malaria and the U.S.' President's Malaria Initiative. We believe that a fresh look should be taken at the cost/benefit of patents particularly related

  12. Induction of HO-1 in tissue macrophages and monocytes in fatal falciparum malaria and sepsis

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    Liomba N


    Full Text Available Abstract Background As well as being inducible by haem, haemoxygenase -1 (HO-1 is also induced by interleukin-10 and an anti-inflammatory prostaglandin, 15d PGJ2, the carbon monoxide thus produced mediating the anti-inflammatory effects of these molecules. The cellular distribution of HO-1, by immunohistochemistry, in brain, lung and liver in fatal falciparum malaria, and in sepsis, is reported. Methods Wax sections were stained, at a 1:1000 dilution of primary antibody, for HO-1 in tissues collected during paediatric autopsies in Blantyre, Malawi. These comprised 37 acutely ill comatose patients, 32 of whom were diagnosed clinically as cerebral malaria and the other 5 as bacterial diseases with coma. Another 3 died unexpectedly from an alert state. Other control tissues were from Australian adults. Results Apart from its presence in splenic red pulp macrophages and microhaemorrhages, staining for HO-1 was confined to intravascular monocytes and certain tissue macrophages. Of the 32 clinically diagnosed cerebral malaria cases, 11 (category A cases had negligible histological change in the brain and absence of or scanty intravascular sequestration of parasitized erythrocytes. Of these 11 cases, eight proved at autopsy to have other pathological changes as well, and none of these eight showed HO-1 staining within the brain apart from isolated moderate staining in one case. Two of the three without another pathological diagnosis showed moderate staining of scattered monocytes in brain vessels. Six of these 11 (category A cases exhibited strong lung staining, and the Kupffer cells of nine of them were intensely stained. Of the seven (category B cases with no histological changes in the brain, but appreciable sequestered parasitised erythrocytes present, one was without staining, and the other six showed strongly staining, rare or scattered monocytes in cerebral vessels. All six lung sections not obscured by neutrophils showed strong staining of


    Directory of Open Access Journals (Sweden)

    Dipen Kumar Bhattacharyya


    Full Text Available BACKGROUND An alarming incidence and severity of jaundice in Malaria, especially in the Plasmodium falciparum variety, has been reported from various parts of the world and at times it causes diagnostic dilemma in both endemic and non-endemic areas, even sometimes affecting the outcome adversely. There are reports depicting association of severe jaundice with falciparum malaria masquerading as fulminant hepatic failure. This study is done to clinically evaluate the cases of malaria with hepatitis in terms of its presentations, extent of hepatic involvement and biochemical parameters. MATERIAL AND METHOD This study was done on 100 confirmed cases of malaria with jaundice, who were admitted in Gauhati Medical College and Hospital during a period of 12 months (1 st July 2012 to 30 th June 2013. Patients were admitted due to complications of malaria like jaundice, nausea and vomiting, pain abdomen, respiratory difficulty, oliguria, altered sensorium, etc. Detailed history, clinical examination, biochemical parameters for liver function test and other blood tests were done in all patients. RESULTS Age of the patients ranged from 13-55 years. Among all patients, 96% cases were P. falciparum and 4% cases were P. vivax. Fever and jaundice were present in 100% of cases. Among the cases, 14% had only splenomegaly, 30% had only hepatomegaly whereas 56% had enlargement of both the organs. The mean serum bilirubin level was 8.9 ± 8 mg/dL with predominantly conjugated hyperbilirubinaemia. Majority of the cases had elevated transaminases and alkaline phosphatase levels. Lowering of serum albumin level and derangement of prothrombin time was also noted in more than half of the patients while serum ammonia was elevated in small number of cases. Acute renal failure and cerebral malaria were the other complications noted frequently in cases of Malaria presenting with jaundice. CONCLUSION The evidence of predominant conjugated hyperbilirubinaemia, increased levels

  14. Enzymes of heme metabolism in the kidney: regulation by trace metals which do not form heme complexes. (United States)

    Maines, M D; Kappas, A


    The in vivo regulation by metal ions of the enzymes of heme metabolism in kidney-particularly of ALAS, the rate-limiting enzyme in heine formation- was investigated. Ni(2+) and Pt(4+), metals which do not enzymatically form metalloporphyrins, were found to regulate ALAS in kidney as they do in liver. The pattern of this regulation was generally similar to that observed with heme and metal ions in liver, i.e., a late increase in enzyme activity after an early period in which ALAS activity was unaltered or inhibited. The metals did not interact with the enzyme in vitro to alter its activity. In this study no direct reciprocal relationship between ALAS activity and total cellular heine content was demonstrated. The metal ions, particularly Pt(4+), also altered the activity of other enzymes of heme biosynthesis in kidney. Pt(4+) severely inhibited the activity of ALAD and UROS. Ni(2+) and Pt(4+) were potent inducers of heme oxygenase, the initial and rate-limiting enzyme in heine degradation. It is proposed that the physiological regulation of ALAS is mediated through the action of metal ions, rather than by the cellular content of heine, and that the regulation of ALAS by heine reflects the action of the central metal ion of heme rather than that of the entire metalloporphyrin complex. In this proposed mechanism for metal ion regulation of ALAS, the tetrapyrrole moiety of heine is considered to function principally as an efficient carrier of metal to the regulatory site for ALAS production, inasmuch as the tetrapyrrole ring itself has been shown in earlier studies not to have any effect on ALAS activity. The production of heine oxygenase is believed to be similarly regulated.

  15. Epidemiologia de la malaria falciparum complicada: estudio de casos y controles en Tumaco y Turbo, Colombia, 2003 The epidemiology of complicated falciparum malaria: case and controls study in Tumaco and Turbo, Colombia, 2003

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    Alberto Tobón C.


    Full Text Available OBJETIVOS: Identificar aspectos del hospedero, del parásito y del ambiente asociados con ocurrencia de malaria por Plasmodium falciparum complicada. MÉTODOS: Estudio de casos y controles en pacientes de Tumaco y Turbo (Colombia aplicando los criterios de complicación de la Organización Mundial de la Salud. RESULTADOS: Entre noviembre 2002 y julio 2003 se captaron 64 casos (malaria complicada y 135 controles (malaria no complicada. Las complicaciones fueron: hiperparasitemia (40%, falla hepática (36%, síndrome dificultad respiratoria aguda (7%, falla renal (4%, trombocitopenia grave (3%, anemia grave (2%, malaria cerebral (2% e hipoglicemia grave (1%. Se encontraron como factores de riesgo para malaria falciparum complicada: a Los antecedentes de malaria falciparum durante el último año fueron menores en los casos (OR= 7.0 (1.2-43.6 P=0.019; b Mayor uso previo de antimaláricos en los casos (OR=2.2 (1.1-4.4 P=0.031 y c mayor uso de cloroquina en los casos (OR=7.4 (1.1-7.8 P=0.017. Se hallaron los alelos MAD-20 y K1 del gen msp1 y FC-27 e IC-1 del gen msp2, cuya distribución de frecuencias fue similar entre casos y controles, aunque el alelo K1 mostró una variación importante entre grupos (casos: 9.4%, controles: 3.5%. La frecuencia de "signos de peligro" fue significativamente mayor en los casos (OR= 3.3, (1.5-7.4 P=0.001. Los criterios de complicación malárica de la Organización Mundial de la Salud se comparan con otros y se discuten algunas implicaciones. CONCLUSIÓN: Se identificaron como factores de riesgo para malaria falciparum complicada, la ausencia de antecedentes de malaria falciparum en el último año y el uso de antimaláricos antes de llegar al hospital.OBJECTIVES: Aimed at identifying host and parasite aspects associated to the presence of Plasmodium falciparum complicated malaria. METHODS: Case and controls study in patients from Tumaco and Turbo (Colombia. We used the World Health Organization criteria to assess the

  16. Lack of association of interferon regulatory factor 1 with severe malaria in affected child-parental trio studies across three African populations.

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    Valentina D Mangano

    Full Text Available Interferon Regulatory Factor 1 (IRF-1 is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi. No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria.

  17. Lack of Association of Interferon Regulatory Factor 1 with Severe Malaria in Affected Child-Parental Trio Studies across Three African Populations (United States)

    Mangano, Valentina D.; Clark, Taane G.; Green, Angela; Richardson, Anna; Jallow, Muminatou; Sisay-Joof, Fatou; Pinder, Margaret; Griffiths, Michael J.; Newton, Charles; Peshu, Norbert; Williams, Thomas N.; Marsh, Kevin; Molyneux, Malcolm E.; Taylor, Terrie E.; Modiano, David; Kwiatkowski, Dominic P.; Rockett, Kirk A.


    Interferon Regulatory Factor 1 (IRF-1) is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs) across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi). No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia) was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria. PMID:19145247

  18. Emerging new trends of malaria in children: A study from a tertiary care centre in northern India

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    Medha Mittal


    Full Text Available Background & objectives: Vivax malaria has long been considered a benign entity. However, an increasing number of reports are highlighting that it may no longer be so. An investigation was carried out to study the profile of malarial admissions in a tertiary care pediatric hospital and to analyse the burden of vivax-related complications. Methods: It is a retrospective observational study. The medical case records of all the patients admitted in the year 2011 with the clinical diagnosis of malaria and laboratory evidence in the form of positive peripheral smear and/or rapid malarial antigen test were retrieved and retrospectively analysed. Results: Overall, 198 cases were included, 128 (64.6% were due to Plasmodium vivax, 66 (33.3% due to P. falciparum and 4 (2% had evidence of mixed infection of Pv + Pf. The clinical features on admission were similar in all the groups. In total, 64/128 (50% patients with vivax infection had one or more complications with severe anemia in 33 (26% and cerebral malaria in 16 (12.5%. Six deaths were reported in P. vivax cases. In the falciparum group, 52 (78.8% had one or more complications with severe anemia in 37 (56.1% and cerebral malaria in 24 (36.4%. Four deaths were reported in P. falciparum cases. Interpretation & conclusion: Overall because of their larger numbers, vivax patients outnumbered other groups, with regards to severe complications and deaths. It was concluded that vivax malaria is emerging as an important cause of malaria-related complications in children.

  19. Malaria Chemoprophylaxis in Military Aircrew (United States)


    for WHO Group 1I endemic deficiency, including macrocytic anemia , areas. aphthous ulcers, and stomatitis. - Chemoprophylaxis for WHO Group III endemic...deficiency is an absolute contraindication because of the risk of -- docetaxel (Taxotere®) hemolytic anemia . This defect is known to affect...headache shown such a property. - accommodation disorders - agranulocytosis, anemia and CONCLUSION methemoglobinemia The choice of malaria

  20. Malaria: developing an action programme. (United States)

    Seadzi, G K; Nyonator, F K


    Malaria is the most common reason that people seek medical care in Ghana. This situation is taken for granted by the people, and there is no organized prevention effort. A World Health Organization-sponsored pilot malaria eradication program (1958-64) was abandoned after a peak period of activity in 1963 when vector control included indoor spraying with DDT. Recently there has been an upward trend in the incidence of malaria, with 15% of all cases becoming complicated. The main vector species are A. gambiae, A. melas, and A. funestus, and the predominant parasite species is Plasmodium falciparum. Treatment of choice is chloroquine phosphate, and although drug resistance has been suspected, it has not been documented. All health facilities are stretched to the limit with regard to the diagnosis and treatment of malaria. Field research is needed to provide a more accurate picture of the current situation. The clinical ability to deliver prompt diagnoses and treatment must be strengthened, and public health education must be instituted. The regional health management system must be improved, and personnel must be taught to use collected data. The use of bed nets, which is common in the south, should be encouraged, and impregnated nets should be introduced.

  1. President’s Malaria Initiative (United States)


    the single most serious several projects on the bionomics and health hazard to Allied troops in the ecology of Anopheles in West Java, South Pacific...Malawi, Mozambique , (USAID) to train health workers in the Rwanda and Senegal were initiated, and diagnosis and control of malaria. I also in FY 2008

  2. Chemical biology: Knockout for malaria (United States)

    Krysiak, Joanna; Sieber, Stephan A.


    Discovering and validating new targets is urgently required to tackle the rise in resistance to antimalarial drugs. Now, inhibition of the enzyme N-myristoyltransferase has been shown to prevent the formation of a critical subcellular organelle in the parasite that causes malaria, leading to death of the parasite.

  3. The dppBCDF gene cluster of Haemophilus influenzae: Role in heme utilization

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    Morton Daniel J


    Full Text Available Abstract Background Haemophilus influenzae requires a porphyrin source for aerobic growth and possesses multiple mechanisms to obtain this essential nutrient. This porphyrin requirement may be satisfied by either heme alone, or protoporphyrin IX in the presence of an iron source. One protein involved in heme acquisition by H. influenzae is the periplasmic heme binding protein HbpA. HbpA exhibits significant homology to the dipeptide and heme binding protein DppA of Escherichia coli. DppA is a component of the DppABCDF peptide-heme permease of E. coli. H. influenzae homologs of dppBCDF are located in the genome at a point distant from hbpA. The object of this study was to investigate the potential role of the H. influenzae dppBCDF locus in heme utilization. Findings An insertional mutation in dppC was constructed and the impact of the mutation on the utilization of both free heme and various proteinaceous heme sources as well as utilization of protoporphyrin IX was determined in growth curve studies. The dppC insertion mutant strain was significantly impacted in utilization of all tested heme sources and protoporphyin IX. Complementation of the dppC mutation with an intact dppCBDF gene cluster in trans corrected the growth defects seen in the dppC mutant strain. Conclusion The dppCBDF gene cluster constitutes part of the periplasmic heme-acquisition systems of H. influenzae.

  4. The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption

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    Valerie Weinborn


    Full Text Available The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study. Study I focused on the effects of cereal proteins (zein, gliadin and glutelin and study II on the effects of legume proteins (soy, pea and lentil on heme Fe absorption. When heme was given alone (as a control, study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05. In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p < 0.05. These results suggest that with the exception of soy proteins, which decreased absorption, proteins derived from cereals and legumes do not affect heme Fe absorption.

  5. Heme degrading protein HemS is involved in oxidative stress response of Bartonella henselae.

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    MaFeng Liu

    Full Text Available Bartonellae are hemotropic bacteria, agents of emerging zoonoses. These bacteria are heme auxotroph Alphaproteobacteria which must import heme for supporting their growth, as they cannot synthesize it. Therefore, Bartonella genome encodes for a complete heme uptake system allowing the transportation of this compound across the outer membrane, the periplasm and the inner membranes. Heme has been proposed to be used as an iron source for Bartonella since these bacteria do not synthesize a complete system required for iron Fe³⁺ uptake. Similarly to other bacteria which use heme as an iron source, Bartonellae must transport this compound into the cytoplasm and degrade it to allow the release of iron from the tetrapyrrole ring. For Bartonella, the gene cluster devoted to the synthesis of the complete heme uptake system also contains a gene encoding for a polypeptide that shares homologies with heme trafficking or degrading enzymes. Using complementation of an E. coli mutant strain impaired in heme degradation, we demonstrated that HemS from Bartonella henselae expressed in E. coli allows the release of iron from heme. Purified HemS from B. henselae binds heme and can degrade it in the presence of a suitable electron donor, ascorbate or NADPH-cytochrome P450 reductase. Knocking down the expression of HemS in B. henselae reduces its ability to face H₂O₂ induced oxidative stress.

  6. The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption. (United States)

    Weinborn, Valerie; Pizarro, Fernando; Olivares, Manuel; Brito, Alex; Arredondo, Miguel; Flores, Sebastián; Valenzuela, Carolina


    The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study). Study I focused on the effects of cereal proteins (zein, gliadin and glutelin) and study II on the effects of legume proteins (soy, pea and lentil) on heme Fe absorption. When heme was given alone (as a control), study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05). In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p legumes do not affect heme Fe absorption.

  7. High throughput heme assay by detection of chemiluminescence of reconstituted horseradish peroxidase. (United States)

    Takahashi, Shigekazu; Masuda, Tatsuru


    In living organisms, heme is an essential molecule for various biological functions. Recent studies also suggest that heme functions as organelle-derived signal that regulates fundamental cell processes. Furthermore, estimation of heme is widely used for studying various blood disorders. In this regard, development of a rapid, sensitive, and high throughput heme assay has been sought. The most frequently used method of measuring heme by pyridine hemochrome is time, labor, and material intensive, and therefore limiting in its utility for large scale, high throughput analysis. Recently, we reported alternative method that is sensitive and specific to heme, which is based on the ability of horseradish peroxidase (HRP) apo-enzyme to reconstitute with heme to form an active holo-enzyme. Here, we developed high throughput heme assay by performing reactions on multi-well plate with highly sensitive chemiluminescence detection reagents. Detection of chemiluminescence in charged coupled device (CCD)-based gel doc apparatus enables simultaneous measurement of multiple samples. Furthermore, the high sensitivity of this assay allowed a direct measurement of heme in solvent extracts after dilution. This assay is sensitive, quick, provides a large dynamic range, and is well suited for large-scale analysis of heme extracted from minute amount of samples.

  8. Alteration by irradiation and storage at amount of heme iron in poultry meat; Alteracoes provocadas pela irradiacao e armazenamento nos teores de ferro heme em carne de frango

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Adriana Regia Marques de; Arthur, Valter Arthur [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Irradiacao de Alimentos e Radioentomologia; Canniatti-Brazaca, Solange Guidolin [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao]. E-mail:


    Studies of irradiation and storage effects in chicken were carried out to discover the influence in iron heme, non-heme amount, color and total pigments. Chicken thighs and chicken breast were studied. These were irradiated to 0, 1 and 2 kGy stored by 14 days to 4 deg C in refrigerator. Determining the heme content and non-heme of meat was done using the colorimeter method and the Ferrozine reagent. The values of iron heme were influenced both by the irradiation and the storage, reducing the amount throughout the course of time. The iron non-heme was also influenced by the doses and the storage time, however the values increased throughout the course of time, because of the conversion of iron heme in non-heme. The color did not show that it was influenced by the studied doses, except for the storage, and the total number of pigments was affected by the irradiation and the time, reducing the values with the increase of storage. Irradiation was shown to be a good method to conserve iron. (author)

  9. Laboratory diagnosis of malaria -- overview. (United States)

    Bhatt, K M


    Features of the laboratory diagnosis of malaria are described. Microscope equipment is absolutely essential. Clinical symptoms are inadequate for the proper diagnosis of malaria. Screening for malaria involves identification of all cases where high fever is present in endemic areas. Diagnosis is complicated because many people take antimalarial drugs which reduce the chances of detecting malarial parasites. Confirmation should be made before treatment is administered. A thick blood slide can be quickly and cheaply taken without much training of health personnel. The disadvantage of thick stains is the difficulty in identifying "plasmodium" strains. When a thin smear with Giemsa and Leishmanin stain is used, a light infection may be missed. Thin smears require trained personnel and time, which in peak seasons may be impractical. Urinary tract and viral infections may be confused with malaria. Evidence of parasites can be discerned from thick stains. Modern assay techniques are also available. There are enzyme linked immunosorbent assays (ELISA) and immunofluorescent assay techniques (IFAT), which are frequently used in large scale seroepidemiological studies. DNA probes have the limitation of radioisotope handling problems. Acridine orange fluorescent microscopy with capillary centrifuged blood is a technique which improves the viability of Giemsa stain procedures. This technique is desirable because of the sensitivity and speed of diagnosis. The quantitative buddy coat (GBC) technique is superior to Giemsa stained thick blood film in identifying malaria, but it is not reliable with mixed infections. Advanced techniques are not readily available in local settings. The recommendation is to continue use of thick or thin blood film and trained health personnel. Laboratory results must be interpreted in the context of when the flood film was prepared, prior drug administration, and clinical manifestations.

  10. The impact of genetic susceptibility to systemic lupus erythematosus on placental malaria in mice.

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    Michael Waisberg

    Full Text Available Severe malaria, including cerebral malaria (CM and placental malaria (PM, have been recognized to have many of the features of uncontrolled inflammation. We recently showed that in mice genetic susceptibility to the lethal inflammatory autoimmune disease, systemic lupus erythematosus (SLE, conferred resistance to CM. Protection appeared to be mediated by immune mechanisms that allowed SLE-prone mice, prior to the onset of overt SLE symptoms, to better control their inflammatory response to Plasmodium infection. Here we extend these findings to ask does SLE susceptibility have 1 a cost to reproductive fitness and/or 2 an effect on PM in mice? The rates of conception for WT and SLE susceptible (SLE(s mice were similar as were the number and viability of fetuses in pregnant WT and SLE(s mice indicating that SLE susceptibility does not have a reproductive cost. We found that Plasmodium chabaudi AS (Pc infection disrupted early stages of pregnancy before the placenta was completely formed resulting in massive decidual necrosis 8 days after conception. Pc-infected pregnant SLE(s mice had significantly more fetuses (∼1.8 fold but SLE did not significantly affect fetal viability in infected animals. This was despite the fact that Pc-infected pregnant SLE(s mice had more severe symptoms of malaria as compared to Pc-infected pregnant WT mice. Thus, although SLE susceptibility was not protective in PM in mice it also did not have a negative impact on reproductive fitness.

  11. The Impact of Genetic Susceptibility to Systemic Lupus Erythematosus on Placental Malaria in Mice (United States)

    Waisberg, Michael; Lin, Christina K.; Huang, Chiung-Yu; Pena, Mirna; Orandle, Marlene; Bolland, Silvia; Pierce, Susan K.


    Severe malaria, including cerebral malaria (CM) and placental malaria (PM), have been recognized to have many of the features of uncontrolled inflammation. We recently showed that in mice genetic susceptibility to the lethal inflammatory autoimmune disease, systemic lupus erythematosus (SLE), conferred resistance to CM. Protection appeared to be mediated by immune mechanisms that allowed SLE-prone mice, prior to the onset of overt SLE symptoms, to better control their inflammatory response to Plasmodium infection. Here we extend these findings to ask does SLE susceptibility have 1) a cost to reproductive fitness and/or 2) an effect on PM in mice? The rates of conception for WT and SLE susceptible (SLEs) mice were similar as were the number and viability of fetuses in pregnant WT and SLEs mice indicating that SLE susceptibility does not have a reproductive cost. We found that Plasmodium chabaudi AS (Pc) infection disrupted early stages of pregnancy before the placenta was completely formed resulting in massive decidual necrosis 8 days after conception. Pc-infected pregnant SLEs mice had significantly more fetuses (∼1.8 fold) but SLE did not significantly affect fetal viability in infected animals. This was despite the fact that Pc-infected pregnant SLEs mice had more severe symptoms of malaria as compared to Pc-infected pregnant WT mice. Thus, although SLE susceptibility was not protective in PM in mice it also did not have a negative impact on reproductive fitness. PMID:23675429

  12. From "forest malaria" to "bromeliad malaria": a case-study of scientific controversy and malaria control. (United States)

    Gadelha, P


    The article analyses the evolution of knowledge and rationale of control of a special case of malaria transmission based on Bromelia-Kerteszia complex. Since bromeliaceae function as a 'host of the carrier' and were previously associated with natural forests, the elucidation of bromeliad malaria historically elicited controversies concerning the imputation of Kertesziae as transmitters as well as over control strategies directed to bromelia eradication (manual removal, herbicides and deforestation), use of insecticides and chemoprophylaxis. Established authority, disciplinary traditions, conceptual premises and contemporary criteria for validating knowledge in the field partly explain the long time gap since Adolpho Lutz announced at the beginning of the century the existence of a new mosquito and breeding site as responsible for a 'forest malaria' epidemic occurring at a high altitude. The article brings attention to how economic, political and institutional determinants played an important role in redefining studies that led both in Trinidad and Brazil to the recognition of the importance of kerteszia transmission, including urban areas, and establishing new approaches to its study, most relevant of all the concurrence of broad ecological research. The article then describes the Brazilian campaign strategies which showed significant short-term results but had to wait four decades to achieve the goal of eradication due to the peculiar characteristics of this pathogenic complex. Finally, it brings attention to the importance of encompassing social values and discourses, in this case, environmental preservation, to understanding historical trends of malaria control programs.

  13. Challenging Density Functional Theory Calculations with Hemes and Porphyrins

    Directory of Open Access Journals (Sweden)

    Sam P. de Visser


    Full Text Available In this paper we review recent advances in computational chemistry and specifically focus on the chemical description of heme proteins and synthetic porphyrins that act as both mimics of natural processes and technological uses. These are challenging biochemical systems involved in electron transfer as well as biocatalysis processes. In recent years computational tools have improved considerably and now can reproduce experimental spectroscopic and reactivity studies within a reasonable error margin (several kcal·mol−1. This paper gives recent examples from our groups, where we investigated heme and synthetic metal-porphyrin systems. The four case studies highlight how computational modelling can correctly reproduce experimental product distributions, predicted reactivity trends and guide interpretation of electronic structures of complex systems. The case studies focus on the calculations of a variety of spectroscopic features of porphyrins and show how computational modelling gives important insight that explains the experimental spectra and can lead to the design of porphyrins with tuned properties.

  14. Heme oxygenase-1 deficiency: the first autopsy case. (United States)

    Kawashima, Atsuhiro; Oda, Yoshio; Yachie, Akihiro; Koizumi, Shoichi; Nakanishi, Isao


    This article describes the first autopsy case of heme oxygenase (HO)-1 deficiency. A 6-year-old boy who presented with growth retardation; anemia; leukocytosis; thrombocytosis; coagulation abnormality; elevated levels of haptoglobin, ferritin, and heme in serum; a low serum bilirubin concentration; and hyperlipidemia was diagnosed as HO-1 deficient by gene analysis several months before death. Autopsy showed amyloid deposits in the liver and adrenal glands and mesangioproliferative glomerular changes in kidneys, in addition to an irregular distribution of foamy macrophages with iron pigments. Fatty streaks and fibrous plaques were noted in the aorta. Compared with HO-1--targeted mice, the present case seems to more severely involve endothelial cells and the reticuloendothelial system, resulting in intravascular hemolysis, disseminated intravascular coagulation, and amyloidosis with a short survival. This contrasts to the predominant iron metabolic disorders of HO-1--targeted mice with a long survival.

  15. Heme oxygenase-1 induction by dieldrin in dopaminergic cells. (United States)

    Kim, Do Kyung; Kim, Jae-Sung; Kim, Ji-Eun; Kim, Sung-Jun; Lee, Jung-Sup; Kim, Dae-Joong; Son, Jin H; Chun, Hong Sung


    We investigated the transcriptional events and signaling pathways involved in the induction of heme oxygenase-1 (HO-1) by dieldrin, an environmental risk factor of Parkinson's disease, in a dopaminergic neuronal cells (SN4741). Dieldrin exposure caused dose-dependent and time-dependent induction of heme oxygenase activity and HO-1 protein expression. Deletional and mutational analyses showed that the 5' distal enhancers, E1 and E2, mediate dieldrin-induced HO-1 gene transcription, and the AP-1 DNA binding sites in the E2 enhancer are critical for E2-mediated HO-1 gene activation. Furthermore, both the p38 and JNK mitogen-activated protein kinase pathways are utilized for HO-1 transcriptional activation by dieldrin. HO-1 inhibitor, ZnPP IX reduced the expression of HO-1 but enhanced the cytotoxicity induced by dieldrin.

  16. Cyanide binding to human plasma heme-hemopexin: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Ascenzi, Paolo, E-mail: [Laboratorio Interdipartimentale di Microscopia Elettronica, Universita Roma Tre, Roma (Italy); Istituto Nazionale di Biostrutture e Biosistemi, Roma (Italy); Leboffe, Loris [Istituto Nazionale di Biostrutture e Biosistemi, Roma (Italy); Polticelli, Fabio [Dipartimento di Biologia, Universita Roma Tre, Roma (Italy)


    Highlights: Black-Right-Pointing-Pointer Cyanide binding to ferric HHPX-heme-Fe. Black-Right-Pointing-Pointer Cyanide binding to ferrous HHPX-heme-Fe. Black-Right-Pointing-Pointer Dithionite-mediated reduction of ferric HHPX-heme-Fe-cyanide. Black-Right-Pointing-Pointer Cyanide binding to HHPX-heme-Fe is limited by ligand deprotonation. Black-Right-Pointing-Pointer Cyanide dissociation from HHPX-heme-Fe-cyanide is limited by ligand protonation. -- Abstract: Hemopexin (HPX) displays a pivotal role in heme scavenging and delivery to the liver. In turn, heme-Fe-hemopexin (HPX-heme-Fe) displays heme-based spectroscopic and reactivity properties. Here, kinetics and thermodynamics of cyanide binding to ferric and ferrous hexa-coordinate human plasma HPX-heme-Fe (HHPX-heme-Fe(III) and HHPX-heme-Fe(II), respectively), and for the dithionite-mediated reduction of the HHPX-heme-Fe(III)-cyanide complex, at pH 7.4 and 20.0 Degree-Sign C, are reported. Values of thermodynamic and kinetic parameters for cyanide binding to HHPX-heme-Fe(III) and HHPX-heme-Fe(II) are K = (4.1 {+-} 0.4) Multiplication-Sign 10{sup -6} M, k{sub on} = (6.9 {+-} 0.5) Multiplication-Sign 10{sup 1} M{sup -1} s{sup -1}, and k{sub off} = 2.8 Multiplication-Sign 10{sup -4} s{sup -1}; and H = (6 {+-} 1) Multiplication-Sign 10{sup -1} M, h{sub on} = 1.2 Multiplication-Sign 10{sup -1} M{sup -1} s{sup -1}, and h{sub off} = (7.1 {+-} 0.8) Multiplication-Sign 10{sup -2} s{sup -1}, respectively. The value of the rate constant for the dithionite-mediated reduction of the HHPX-heme-Fe(III)-cyanide complex is l = 8.9 {+-} 0.8 M{sup -1/2} s{sup -1}. HHPX-heme-Fe reactivity is modulated by proton acceptor/donor amino acid residue(s) (e.g., His236) assisting the deprotonation and protonation of the incoming and outgoing ligand, respectively.

  17. Reversible cerebral vasoconstriction syndrome

    Directory of Open Access Journals (Sweden)

    Saini Monica


    Full Text Available Reversible cerebral vasoconstriction syndromes (RCVS are a group of disorders that have in common an acute presentation with headache, reversible vasoconstriction of cerebral arteries, with or without neurological signs and symptoms. In contrast to primary central nervous system vasculitis, they have a relatively benign course. We describe here a patient who was diagnosed with RCVS.

  18. Mosaic origin of the heme biosynthesis pathway in photosynthetic eukaryotes. (United States)

    Oborník, Miroslav; Green, Beverley R


    Heme biosynthesis represents one of the most essential metabolic pathways in living organisms, providing the precursors for cytochrome prosthetic groups, photosynthetic pigments, and vitamin B(12). Using genomic data, we have compared the heme pathway in the diatom Thalassiosira pseudonana and the red alga Cyanidioschyzon merolae to those of green algae and higher plants, as well as to those of heterotrophic eukaryotes (fungi, apicomplexans, and animals). Phylogenetic analyses showed the mosaic character of this pathway in photosynthetic eukaryotes. Although most of the algal and plant enzymes showed the expected plastid (cyanobacterial) origin, at least one of them (porphobilinogen deaminase) appears to have a mitochondrial (alpha-proteobacterial) origin. Another enzyme, glutamyl-tRNA synthase, obviously originated in the eukaryotic nucleus. Because all the plastid-targeted sequences consistently form a well-supported cluster, this suggests that genes were either transferred from the primary endosymbiont (cyanobacteria) to the primary host nucleus shortly after the primary endosymbiotic event or replaced with genes from other sources at an equally early time, i.e., before the formation of three primary plastid lineages. The one striking exception to this pattern is ferrochelatase, the enzyme catalyzing the first committed step to heme and bilin pigments. In this case, two red algal sequences do not cluster either with the other plastid sequences or with cyanobacterial sequences and appear to have a proteobacterial origin like that of the apicomplexan parasites Plasmodium and Toxoplasma. Although the heterokonts also acquired their plastid via secondary endosymbiosis from a red alga, the diatom has a typical plastid-cyanobacterial ferrochelatase. We have not found any remnants of the plastidlike heme pathway in the nonphotosynthetic heterokonts Phytophthora ramorum and Phytophthora sojae.

  19. Ecology, economics and political will: the vicissitudes of malaria strategies in Asia. (United States)

    Kidson, C; Indaratna, K


    The documented history of malaria in parts of Asia goes back more than 2,000 years, during which the disease has been a major player on the socioeconomic stage in many nation states as they waxed and waned in power and prosperity. On a much shorter time scale, the last half century has seen in microcosm a history of large fluctuations in endemicity and impact of malaria across the spectrum of rice fields and rain forests, mountains and plains that reflect the vast ecological diversity inhabited by this majority aggregation of mankind. That period has seen some of the most dramatic changes in social and economic structure, in population size, density and mobility, and in political structure in history: all have played a part in the changing face of malaria in this extensive region of the world. While the majority of global malaria cases currently reside in Africa, greater numbers inhabited Asia earlier this century before malaria programs savored significant success, and now Asia harbors a global threat in the form of the epicenter of multidrug resistant Plasmodium falciparum which is gradually encompassing the tropical world. The latter reflects directly the vicissitudes of economic change over recent decades, particularly the mobility of populations in search of commerce, trade and personal fortunes, or caught in the misfortunes of physical conflicts. The period from the 1950s to the 1990s has witnessed near "eradication" followed by resurgence of malaria in Sri Lanka, control and resurgence in India, the influence of war and postwar instability on drug resistance in Cambodia, increase in severe and cerebral malaria in Myanmar during prolonged political turmoil, the essential disappearance of the disease from all but forested border areas of Thailand where it remains for the moment intractable, the basic elimination of vivax malaria from many provinces of central China. Both positive and negative experiences have lessons to teach in the debate between eradication

  20. A role for Haemophilus ducreyi Cu,ZnSOD in resistance to heme toxicity. (United States)

    Negari, Shahin; Sulpher, Jeff; Pacello, Francesca; Ingrey, Keely; Battistoni, Andrea; Lee, B Craig


    The Cu,Zn superoxide dismutase (Cu,ZnSOD) from Haemophilus ducreyi is the only enzyme of this class which binds a heme molecule at its dimer interface. To explore the role of the enzyme in this heme-obligate bacterium, a sodC mutant was created by insertional inactivation. No difference in growth rate was observed during heme limitation. In contrast, under heme rich conditions growth of the sodC mutant was impaired compared to the wild type strain. This growth defect was abolished by supplementation of exogenous catalase. Genetic complementation of the sodC mutant in trans demonstrated that the enzymatic property or the heme-binding activity of the protein could repair the growth defect of the sodC mutant. These results indicate that Cu,ZnSOD protects Haemophilus ducreyi from heme toxicity.

  1. Protective role of heme oxygenase-1 against inflammation in atherosclerosis. (United States)

    Durante, William


    Heme oxygenase-1 (HO-1) catalyzes the first and rate-limiting step in the metabolism of free heme into equimolar amounts of ferrous iron, carbon monoxide (CO), and biliverdin. Biliverdin is subsequently converted to bilirubin by biliverdin reductase. HO-1 has recently been identified as a promising therapeutic target in the treatment of vascular inflammatory disease, including atherosclerosis. HO-1 represses inflammation by removing the pro-inflammatory molecule heme and by generating CO and the bile pigments, biliverdin and bilirubin. These HO-1 reaction products are capable of blocking innate and adaptive immune responses by modifying the activation, differentiation, maturation, and/or polarization of numerous immune cells, including endothelial cells, monocytes/macrophages, dendritic cells, T lymphocytes, mast cells, and platelets. These cellular actions by CO and bile pigments result in diminished leukocyte recruitment and infiltration, and pro-inflammatory mediator production within atherosclerotic lesions. This review highlights the mechanisms by which HO-1 suppresses vascular inflammation in atherosclerosis, and explores possible therapeutic modalities by which HO-1 and its reaction products can be employed to ameliorate vascular inflammatory disease.

  2. Nitric oxide heme interactions in nitrophorin from Cimex lectularius (United States)

    Christmann, R.; Auerbach, H.; Berry, R. E.; Walker, F. A.; Schünemann, V.


    The nitrophorin from the bedbug Cimex lectularius (cNP) is a nitric oxide (NO) carrying protein. Like the nitrophorins (rNPs) from the kissing bug Rhodnius prolixus, cNP forms a stable heme Fe(III)-NO complex, where the NO can be stored reversibly for a long period of time. In both cases, the NPs are found in the salivary glands of blood-sucking bugs. The insects use the nitrophorins to transport the NO to the victim's tissues, resulting in vasodilation and reduced blood coagulation. However, the structure of cNP is significantly different to those of the rNPs from Rhodnius prolixus. Furthermore, the cNP can bind a second NO molecule to the proximal heme cysteine when present at higher concentrations. High field Mössbauer spectroscopy on 57Fe enriched cNP complexed with NO shows reduction of the heme iron and formation of a ferrous nitric oxide (Fe(II)-NO) complex. Density functional theory calculations reproduce the experimental Mössbauer parameters and confirm this observation.

  3. Progress towards malaria control targets in relation to national malaria programme funding

    NARCIS (Netherlands)

    E.L. Korenromp (Eline); M. Hosseini (Mehran); R.D. Newman (Robert D); R.E. Cibulskis (Richard E)


    textabstractBackground: Malaria control has been dramatically scaled up the past decade, mainly thanks to increasing international donor financing since 2003. This study assessed progress up to 2010 towards global malaria impact targets, in relation to Global Fund, other donor and domestic malaria p


    Directory of Open Access Journals (Sweden)

    P. N. Harianto


    Full Text Available Hypoglycemia is a serious and often fatal complication of severe malaria. This condition has been reported in many parts of the world including from Thailand (1983 and from Indonesia by Hoffman (1988 and Harianto (1990. Two main causes that can lead to development of this condition are quinine administration and the severity of the malaria condition itself. A case study is presented about development of prolonged hypoglycemia after quinine administration. A 41 years old male was hospitalized with 4 days history of fever, headache vomiting and icterus. On examination he was found to be in good mental status, had a normal blood pressure, and a body temperature of 40°C. He also had icterus and hepatomegaly. Laboratory examination on admission showed malaria slide positive forRfalciparum ring 30-40, with parasite count of 3% (+ on day I. CBC showed: WBC of 21,700/mm3 and platelet count of 40,000/mm3. Blood chemistry showed glucose level of 77 mm %, serum bilirubin of 29.34 mg % (direct 21.87 mg % SGOT 31 u/l, SGPT 20 u/l, serum ureum 167 mg %, creatinine of 3.36 mg %, serum Na 123 m Eq/L and K 3.99 Eq/L. Urinalysis was normal except for specific gravity of 1.07. After diagnosis of bilious malaria was confirmed, the patient was given i.v. quinine 500 mg diluted in 500 ml 5% dextrose, infused over 4 hours and repeated every 8 hours. On day IVi.v. quinine was switched to oral preparation of 600 mg given bid and the next day quinine was changed to oral chloroquine. The day after admission (30 hours after quinine administration, blood glucose dropped to 21 mg %, 16-46 mg % on day III, and to less than 10 mg % on day IV. It gradulty returned to normal afterwards. Administration of 10% dextrose and boluses of 40% glucose were able to keep the patient in good clinical condition and prevent death. Malaria slide improved on day III, became negative by day IV and serum bilirubin also decreased on follow up. Hypoglycemia should be expected in severe malaria

  5. [Research progress on malaria vector control]. (United States)

    Zhu, Guo-Ding; Cao, Jun; Zhou, Hua-Yun; Gao, Qi


    Vector control plays a crucial role in the stages of malaria control and elimination. Currently, it mainly relies on the chemical control methods for adult mosquitoes in malaria endemic areas, however, it is undergoing the serious threat by insecticide resistance. In recent years, the transgenic technologies of malaria vectors have made a great progress in the laboratory. This paper reviews the challenges of the traditional methods and the rapid developed genetic modified technology in the application of vector control.

  6. The evolution of drug-resistant malaria


    Plowe, Christopher V.


    Molecular epidemiological investigations have uncovered the patterns of emergence and global spread of Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine. Malaria parasites highly resistant to chloroquine and pyrimethamine spread from Asian origins to Africa, at great cost to human health and life. If artemisinin-resistant falciparum malaria follows the same pattern, renewed efforts to eliminate and eradicate malaria will be gravely threatened. This paper, adapted f...

  7. Heme metabolism in stress regulation and protein production: from Cinderella to a key player

    DEFF Research Database (Denmark)

    Martínez, J. L.; Petranovic, D.; Nielsen, Jens


    . Based on our recent findings and other recent reports, we here illustrate that heme is more than a co-factor. We also discuss the necessity to gain more insight into the heme biosynthesis pathway regulation, as this interacts closely with overall stress control. Understanding heme biosynthesis and its...... regulation could impact our ability to develop more efficient yeast cell factories for heterologous protein production....

  8. Clinically Important Features of Porphyrin and Heme Metabolism and the Porphyrias


    Siddesh Besur; Wehong Hou; Paul Schmeltzer; Bonkovsky, Herbert L.


    Heme, like chlorophyll, is a primordial molecule and is one of the fundamental pigments of life. Disorders of normal heme synthesis may cause human diseases, including certain anemias (X-linked sideroblastic anemias) and porphyrias. Porphyrias are classified as hepatic and erythropoietic porphyrias based on the organ system in which heme precursors (5-aminolevulinic acid (ALA), porphobilinogen and porphyrins) are chiefly overproduced. The hepatic porphyrias are further subdivided into acute p...

  9. Porphyrin-induced photodynamic cross-linking of hepatic heme-binding proteins. (United States)

    Vincent, S H; Holeman, B; Cully, B C; Muller-Eberhard, U


    Three types of hepatic proteins, a heme-binding Z protein, a mixture of the glutathione S-transferases and a cytochrome P450 isozyme, were shown to be susceptible to photodynamic cross-linking and loss in antigenicity by naturally occurring porphyrins. At 50 microM, uroporphyrin caused the most and protoporphyrin the least photodecomposition. Hemopexin, a specific serum heme carrier, was photodecomposed but no cross-linking was detected. Heme and scavengers of singlet oxygen partially prevented protein photodecomposition.

  10. The interrelationship of tropical disease and mental disorder: conceptual framework and literature review (Part I--Malaria). (United States)

    Weiss, M G


    Substantial interactions between tropical diseases and psychiatric illness have long been recognized, but the impact of biological factors in the field of cross-cultural psychiatry has been less well studied than psychosocial factors. In reviewing the literature at the intersection of tropical medicine and psychiatry in order to summarize the existing data base in this field, a generalized interactive model informed by the theoretical contributions of George Engel, the WHO Scientific Working Group on Social and Economic Research, Arthur Kleinman, P. M. Yap, Edward Sapir and others has been developed to serve as a conceptual framework for this analysis of the literature and to guide further research. The clinical literature of tropical medicine and psychiatry which recognizes the significance of concurrent tropical disease and mental disorders is reviewed along with the more specific literature on malaria and concomitant psychiatric illness. Many authors have focused on the role of organic mental disorders, especially in connection with cerebral malaria, but several have also addressed psychosocial parameters through which the interrelationship between malaria and a full range of mental disorders is also mediated. The effects of malaria may serve as biological, psychological or social stressors operating in a cultural context which precipitate or shape features of psychiatric symptomatology. Psychiatric illness may likewise precipitate an episode of malaria with typical symptoms in a patient with a previously subclinical infection. Implications of the literature and this generalized interactive model are considered as they apply to clinical practice, public health and the application of social science theory in medicine.

  11. Irradiation of bovine meat: effect of heme-iron concentration.; Irradiacao de carne bovina: efeito na concentracao de ferro heme

    Energy Technology Data Exchange (ETDEWEB)

    Mistura, Liliana Perazzini Furtado


    The irradiation is often used, nowadays, for meat conservation and it is important to know how much this process interferes with the nutritional quality of the meat. In this study round cut meat, ground and steaks (from a local supermarket) was irradiated with doses of O; 1; 2; 3; 4; 5; 7,5 and 10 kGy (JS-7500 Nordium Inc -Canada) and the interference of irradiation and the process of food preparation on heme-iron (H Fe) content was determined. Half of the sample was kept raw and the other half was grilled in a pre-warmed oven at 250 deg C for 9 min and a controlled humidity of 70%. The chemical composition, the total iron (T Fe) (EM) and the heme iron concentration were determined (Hornsey,1956) and the sensorial quality evaluated. The average T Fe concentration of raw and ground , ground and grilled, raw steaks and grilled steak meat, on dry and degreased basis was 113 mug/g, 121 mug/g , 91 mug/g and 77 mug/g; and the H Fe concentration 105 mug/g (93% of T Fe) , 88 mug/g (73% of T Fe), 90 mug/g (99% of T Fe) and 52 mug/g (68% of T Fe) respectively. Data were evaluated by ANOVA with fixed effects and multiple comparisons. The irradiation neither altered the chemical composition nor the proportion of heme iron of meat. The preparation conditions (temperature, cooking time, environment humidity, meat presentation) of the sample interfered more with the heme iron content than the irradiation. With the sensorial analysis we verified that meats irradiated with doses of 3 kGy were better evaluated in softness and succulency attributes than the others. Meat submitted to irradiation doses up to 3 kGy were accepted by the specialists' panel. (author)

  12. Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Amit V., E-mail: [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland); Flueck, Christa E.; Mullis, Primus E. [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland)


    Research highlights: {yields} Mutations in POR identified from patients lead to reduced HO-1 activities. {yields} POR mutation Y181D affecting FMN binding results in total loss of HO-1 activity. {yields} POR mutations A287P, C569Y and V608F, lost 50-70% activity. {yields} Mutations in FAD binding domain, R457H, Y459H and V492E lost all HO-1 activity. {yields} POR polymorphisms P228L, R316W, G413S, A503V and G504R have normal activity. -- Abstract: Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare form of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.

  13. T-cell responses in malaria

    DEFF Research Database (Denmark)

    Hviid, L; Jakobsen, P H; Abu-Zeid, Y A


    Malaria is caused by infection with protozoan parasites of the genus Plasmodium. It remains one of the most severe health problems in tropical regions of the world, and the rapid spread of resistance to drugs and insecticides has stimulated intensive research aimed at the development of a malaria...... vaccine. Despite this, no efficient operative vaccine is currently available. A large amount of information on T-cell responses to malaria antigens has been accumulated, concerning antigens derived from all stages of the parasite life cycle. The present review summarizes some of that information......, and discusses factors affecting the responses of T cells to malaria antigens....

  14. Malaria treatment services in Nigeria: A review

    Directory of Open Access Journals (Sweden)

    Benjamin SC Uzochukwu


    Full Text Available Malaria remains a major Public Health problem in Nigeria and causes death and illness in children and adults, especially pregnant women. Malaria case management remains a vital component of the malaria control strategies. This entails early diagnosis and prompt treatment with effective antimalarial medicines. The objectives of this review is to enable health professionals to understand the magnitude of malaria treatment services in Nigeria, to improve knowledge for rational malaria management within different health system contexts with a view to improving access to malaria treatment. The review therefore looks at the following areas: clinical disease and epidemiology; the burden of malaria in Nigeria; objectives of treatment; antimalarial treatment policy; malaria diagnosis, treatment strategies/ National responses; treatment sources. The review concludes that for improved malaria treatment services in Nigeria, there is an urgent need to develop adequate strategies that will ensure better access to medicines by getting evidence-based and effective medicines to the people who need them, whether by reducing their costs, promoting equity in access, improving their distribution, increasing their efficacy and acceptability, or slowing down the development of antimicrobial resistance.

  15. Heme mediates cytotoxicity from artemisinin and serves as a general anti-proliferation target.

    Directory of Open Access Journals (Sweden)

    Shiming Zhang

    Full Text Available Heme (Fe2+ protoporphyrin IX is an essential molecule that has been implicated the potent antimalarial action of artemisinin and its derivatives, although the source and nature of the heme remain controversial. Artemisinins also exhibit selective cytotoxicity against cancer cells in vitro and in vivo. We demonstrate that intracellular heme is the physiologically relevant mediator of the cytotoxic effects of artemisinins. Increasing intracellular heme synthesis through the addition of aminolevulinic acid, protoporphyrin IX, or transferrin-bound iron increased the cytotoxicity of dihydroartemisinin, while decreasing heme synthesis through the addition of succinyl acetone decreased its cytotoxic activity. A simple and robust high throughput assay was developed to screen chemical compounds that were capable of interacting with heme. A natural products library was screened which identified the compound coralyne, in addition to artemisinin, as a heme interacting compound with heme synthesis dependent cytotoxic activity. These results indicate that cellular heme may serve a general target for the development of both anti-parasitic and anti-cancer therapeutics.

  16. A Novel Approach for Identifying the Heme-Binding Proteins from Mouse Tissues

    Institute of Scientific and Technical Information of China (English)

    Xiaolei Li; Rong Wang; Zhongsheng Sun; Zuyuan Xu; Jingyue Bao; Xiuqing Zhang; Xiaoli Feng; Siqi Liu; Xiaoshan Wang; Kang Zhao; Zhengfeng Zhou; Caifeng Zhao; Ren Yan; Liang Lin; Tingting Lei; Jianning Yin


    Heme is a key cofactor in aerobic life, both in eukaryotes and prokaryotes. Because of the high reactivity of ferrous protoporphyrin IX, the reactions of heme in cells are often carried out through heme-protein complexes. Traditionally studies of hemebinding proteins have been approached on a case by case basis, thus there is a limited global view of the distribution of heme-binding proteins in different cells or tissues. The procedure described here is aimed at profiling hemne-binding proteins in mouse tissues sequentially by 1) purification of heme-binding proteins by hemeagarose, an affinity chromatographic resin; 2) isolation of heme-binding proteins by SDS-PAGE or two-dimensional electrophoresis; 3) identification of heme-binding proteins by mass spectrometry. In five mouse tissues, over 600 protein spots were visualized on 2DE gel stained by Commassie blue and 154 proteins were identified by MALDI-TOF, in which most proteins belong to heme related. This methodology makes it possible to globally characterize the heme-binding proteins in a biological system.

  17. Nitrosylation of c heme in cd(1)-nitrite reductase is enhanced during catalysis. (United States)

    Rinaldo, Serena; Giardina, Giorgio; Cutruzzolà, Francesca


    The reduction of nitrite into nitric oxide (NO) in denitrifying bacteria is catalyzed by nitrite reductase. In several species, this enzyme is a heme-containing protein with one c heme and one d1 heme per monomer (cd1NiR), encoded by the nirS gene. For many years, the evidence of a link between NO and this hemeprotein represented a paradox, given that NO was known to tightly bind and, possibly, inhibit hemeproteins, including cd1NiRs. It is now established that, during catalysis, cd1NiRs diverge from "canonical" hemeproteins, since the product NO rapidly dissociates from the ferrous d1 heme, which, in turn, displays a peculiar "low" affinity for NO (KD=0.11 μM at pH 7.0). It has been also previously shown that the c heme reacts with NO at acidic pH but c heme nitrosylation was not extensively investigated, given that in cd1NiR it was considered a side reaction, rather than a genuine process controlling catalysis. The spectroscopic study of the reaction of cd1NiR and its semi-apo derivative (containing the sole c heme) with NO reported here shows that c heme nitrosylation is enhanced during catalysis; this evidence has been discussed in order to assess the potential of c heme nitrosylation as a regulatory process, as observed for cytochrome c nitrosylation in mammalian mitochondria.

  18. Natural chlorophyll but not chlorophyllin prevents heme-induced cytotoxic and hyperproliferative effects in rat colon. (United States)

    de Vogel, Johan; Jonker-Termont, Denise S M L; Katan, Martijn B; van der Meer, Roelof


    Diets high in red meat and low in green vegetables are associated with an increased risk of colon cancer. In rats, dietary heme, mimicking red meat, increases colonic cytotoxicity and proliferation of the colonocytes, whereas addition of chlorophyll from green vegetables inhibits these heme-induced effects. Chlorophyllin is a water-soluble hydrolysis product of chlorophyll that inhibits the toxicity of many planar aromatic compounds. The present study investigated whether chlorophyllins could inhibit the heme-induced luminal cytotoxicity and colonic hyperproliferation as natural chlorophyll does. Rats were fed a purified control diet, the control diet supplemented with heme, or a heme diet with 1.2 mmol/kg diet of chlorophyllin, copper chlorophyllin, or natural chlorophyll for 14 d (n = 8/group). The cytotoxicity of fecal water was determined with an erythrocyte bioassay and colonic epithelial cell proliferation was quantified in vivo by [methyl-(3)H]thymidine incorporation into newly synthesized DNA. Exfoliation of colonocytes was measured as the amount of rat DNA in feces using quantitative PCR analysis. Heme caused a >50-fold increase in the cytotoxicity of the fecal water, a nearly 100% increase in proliferation, and almost total inhibition of exfoliation of the colonocytes. Furthermore, the addition of heme increased TBARS in fecal water. Chlorophyll, but not the chlorophyllins, completely prevented these heme-induced effects. In conclusion, inhibition of the heme-induced colonic cytotoxicity and epithelial cell turnover is specific for natural chlorophyll and cannot be mimicked by water-soluble chlorophyllins.

  19. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Institute of Scientific and Technical Information of China (English)


    Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS)and horse pathogen Streptococcus equi(S.equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S.equi pathogenesis.Heme is an important source of essential iron for bacterial pathogens.Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS,demonstrated direct heme transfer from one protein to another,demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system,elucidated the activated heme transfer mechanism,and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction.These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Grampositive pathogens.Pathogenesis of GAS is mediated by an abundance of extracellular proteins,and pathogenic role and functional mechanism are not known for many of these virulence factors.Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination.These studies may lead to development of novel strategies to prevent and treat GAS infections.

  20. In vivo and in vitro olefin cyclopropanation catalyzed by heme enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Pedro S.; Brustad, Eric M.; Arnold, Frances H.; Wang, Zhan; Lewis, Jared C.


    The present invention provides methods for catalyzing the conversion of an olefin to any compound containing one or more cyclopropane functional groups using heme enzymes. In certain aspects, the present invention provides a method for producing a cyclopropanation product comprising providing an olefinic substrate, a diazo reagent, and a heme enzyme; and admixing the components in a reaction for a time sufficient to produce a cyclopropanation product. In other aspects, the present invention provides heme enzymes including variants and fragments thereof that are capable of carrying out in vivo and in vitro olefin cyclopropanation reactions. Expression vectors and host cells expressing the heme enzymes are also provided by the present invention.

  1. In vivo and in vitro olefin cyclopropanation catalyzed by heme enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Pedro S; Brustad, Eric M; Arnold, Frances H; Wang, Zhan; Lewis, Jared C


    The present invention provides methods for catalyzing the conversion of an olefin to any compound containing one or more cyclopropane functional groups using heme enzymes. In certain aspects, the present invention provides a method for producing a cyclopropanation product comprising providing an olefinic substrate, a diazo reagent, and a heme enzyme; and admixing the components in a reaction for a time sufficient to produce a cyclopropanation product. In other aspects, the present invention provides heme enzymes including variants and fragments thereof that are capable of carrying out in vivo and in vitro olefin cyclopropanation reactions. Expression vectors and host cells expressing the heme enzymes are also provided by the present invention.

  2. Gene targeting in malaria parasites. (United States)

    Ménard, R; Janse, C


    Gene targeting, which permits alteration of a chosen gene in a predetermined way by homologous recombination, is an emerging technology in malaria research. Soon after the development of techniques for stable transformation of red blood cell stages of Plasmodium falciparum and Plasmodium berghei, genes of interest were disrupted in the two species. The main limitations of gene targeting in malaria parasites result from the intracellular growth and slow replication of these parasites. On the other hand, the technology is facilitated by the very high rate of homologous recombination following transformation with targeting constructs (approximately 100%). Here, we describe (i) the vector design and the type of mutation that may be generated in a target locus, (ii) the selection and screening strategies that can be used to identify clones with the desired modification, and (iii) the protocol that was used for disrupting the circumsporozoite protein (CS) and thrombospondin-related anonymous protein (TRAP) genes of P. berghei.

  3. Malaria in penguins - current perceptions. (United States)

    Grilo, M L; Vanstreels, R E T; Wallace, R; García-Párraga, D; Braga, É M; Chitty, J; Catão-Dias, J L; Madeira de Carvalho, L M


    Avian malaria is a mosquito-borne disease caused by protozoans of the genus Plasmodium, and it is considered one of the most important causes of morbidity and mortality in captive penguins, both in zoological gardens and rehabilitation centres. Penguins are known to be highly susceptible to this disease, and outbreaks have been associated with mortality as high as 50-80% of affected captive populations within a few weeks. The disease has also been reported in wild penguin populations, however, its impacts on the health and fitness of penguins in the wild is not clear. This review provides an overview of the aetiology, life cycle and epidemiology of avian malaria, and provides details on the strategies that can be employed for the diagnostic, treatment and prevention of this disease in captive penguins, discussing possible directions for future research.

  4. [Malaria in Poland in 2006]. (United States)

    Rosińska, Magdalena


    There were 19 cases of malaria meeting European Union case definition for confirmed case registered in Poland in 2006. All of them were imported, including 1 case of relapse: 17 from Africa, 1 from Asia and 1 from Oceania. Species of Plasmodium was determined for 12 cases (68%): P. falciparum in 12 cases and P. vivax in one. There were 15 cases in males and 4 in females. Age at onset ranged from 17 to 59 years and a considerable number of cases occurred in persons 50 years old or older (5.26%). Common reasons for travel to endemic countries included tourism or family visits (10 cases) and professional or missionary travel (5 cases). Only four cases used chemoprophylaxis and the relevant information was missing in 4 cases. In two cases of malaria caused by Pl. falciparum the clinical course was severe and one of them died.

  5. [Malaria in Poland in 2008]. (United States)

    Stepień, Małgorzata


    There were 22 malaria cases confirmed according to the European Union cases definition registered in Poland in 2008. All of them were imported, 13 cases (59%) from Africa, 3 from Asia, 5 from Oceania and 1 from South America. Invasion with Plasmodium falciparum was confirmed in 14 cases, P. vivax in 4 cases, mixed invasion in 2 cases and in 2 cases species of Plasmodium was undetermined. There were 13 cases in males and 9 in females. Age at onset ranged from 23 to 58 years and majority of cases were in the age group 25-40. Common reason for travel to endemic countries were tourism (11 cases) and work-related visits (7 cases). Clinical course was severe in 6 cases of P. falciparum malaria and 1 person died because of the disease. Nine cases used chemoprophylaxis during their travel but only one of them appropriately, relevant information was missing in 6 cases.


    Directory of Open Access Journals (Sweden)

    Harijani A. Marwoto


    Full Text Available A field study on entomology has been conducted in 6 villages which were located in coastal and in-land areas of Sikka Regency of Central Flores since April 1990 - October 1991. The results of this study showed that the suspected malaria vectors in those areas were An. sundaicus, An. subpictus, An. barbirostris, An. aconitus and An. maculatus. Only 3 species were confirmed as vector using ELISA test, i.e. An. sundaicus, An. barbirostris and An. subpictus with sporosoite rates of 4.2%, 2.1% and 0.1% respectively. An. aconitus, a potential malaria vector in Java and in some onther places was not confirmed as vector in Flores yet. The 3 confirmed vectors were also found positive with sporozoites in West Flores and also found predominant in East Flores.

  7. Mating activates the heme peroxidase HPX15 in the sperm storage organ to ensure fertility in Anopheles gambiae (United States)

    Shaw, W. Robert; Teodori, Eleonora; Mitchell, Sara N.; Baldini, Francesco; Gabrieli, Paolo; Rogers, David W.; Catteruccia, Flaminia


    Anopheles gambiae mosquitoes are major African vectors of malaria, a disease that kills more than 600,000 people every year. Given the spread of insecticide resistance in natural mosquito populations, alternative vector control strategies aimed at reducing the reproductive success of mosquitoes are being promoted. Unlike many other insects, An. gambiae females mate a single time in their lives and must use sperm stored in the sperm storage organ, the spermatheca, to fertilize a lifetime's supply of eggs. Maintenance of sperm viability during storage is therefore crucial to the reproductive capacity of these mosquitoes. However, to date, no information is available on the factors and mechanisms ensuring sperm functionality in the spermatheca. Here we identify cellular components and molecular mechanisms used by An. gambiae females to maximize their fertility. Pathways of energy metabolism, cellular transport, and oxidative stress are strongly regulated by mating in the spermatheca. We identify the mating-induced heme peroxidase (HPX) 15 as an important factor in long-term fertility, and demonstrate that its function is required during multiple gonotrophic cycles. We find that HPX15 induction is regulated by sexually transferred 20-hydroxy-ecdysone (20E), a steroid hormone that is produced by the male accessory glands and transferred during copulation, and that expression of this peroxidase is mediated via the 20E nuclear receptor. To our knowledge, our findings provide the first evidence of the mechanisms regulating fertility in Anopheles, and identify HPX15 as a target for vector control. PMID:24711401

  8. Calcium-Dependent Conformation of a Heme and Fingerprint Peptide of the Di-Heme Cytochrome c Peroxidase from Paracoccus Pantotrophus

    Energy Technology Data Exchange (ETDEWEB)



    The structural changes in the heme macrocycle and substituents caused by binding of Ca{sup 2+} to the diheme cytochrome c peroxidase from Paracoccuspantotrophus were clarified by resonance Raman spectroscopy of the inactive filly oxidized form of the enzyme. The changes in the macrocycle vibrational modes are consistent with a Ca{sup 2+}-dependent increase in the out-of-plane distortion of the low-potential heme, the proposed peroxidatic heme. Most of the increase in out-of-plane distortion occurs when the high affinity site I is occupied, but a small further increase in distortion occurs when site II is also occupied by Ca{sup 2+}or Mg{sup 2+}. This increase in the heme distortion also explains the red shift in the Soret absorption band that occurs upon Ca{sup 2+} binding. Changes also occur in the low frequency substituent modes of the heme, indicating that a structural change in the covalently attached fingerprint pentapeptide of the LP heme occurs upon CM{sup 2+} binding to site I. These structural changes, possibly enhanced in the semi-reduced form of the enzyme, may lead to loss of the sixth ligand at the peroxidatic heme and activation of the enzyme.

  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)


    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. The Malaria Problem: short communication

    Directory of Open Access Journals (Sweden)

    Charles Ebikeme


    Full Text Available Malaria is the world's most prevalent infectious disease, a major cause of mortality, and a barrier to social and economic development and growth in many countries throughout the world. Antimalarials represent an important part of strategy to curbing this debilitating disease. The spread of drug resistance is becoming increasingly important. To date, parasite resistance to all but one case of antimalarials exists in most endemic countries. Meaning, new drug to combat the disease are a priority.


    Directory of Open Access Journals (Sweden)

    Emilianan Tjitra


    Full Text Available Previous approaches in malaria treatment fail to reduce the morbidity and mortality of malaria. Widespread overuse of antimalarial treatment of clinical malaria may have contributed to increase drug resistance. Moreover, poor compliance or inadequate dosage also selects for parasite resistance. The paradigm of radical treatment using drug combinations may improve the cure rate and compliance, thereby preventing or delaying the emergence of parasites resistant to antimalarial drugs. The ideal combined antimalarial regimen in Indonesia should be safe and tolerated by all age groups, effective and rapidly acting for both P.falciparum and P.vivax malaria, short course, good compliance and acceptable, without resistance and/or cross-resistance or , not widely spread use, cost-effective and affordable. Artemisinin derivatives are the best partner drug for combination, with advantages that include: well absorbed, safe and well tolerated, rapidly converted to active metabolite, having very short half-life, broad specificity of action, and extremely potent. Current artemisinin-based combinations which are suitable for Indonesia include: amodiaquine plus artesunate given as single daily dose for 3 days (AQ3+ATS3, mefloquine plus artesunate given as single daily dose for 3 days (MQ3+ATS3, lumefantrine/benflumetol plus artemether given as twice daily dose for 3 days (COARTEMETHER, piperaquine plus dihydroartemisinin given as single daily dose for 2-3 days (PPQ2-3+DHA2-3, and piperaquine plus artemisinin given as single daily dose for 2 days (PPQ2+ATM2. Given the imbalance between rapid development of parasite resistance and slow availability of new effective antimalarial drugs, research and development of antimalarial drugs must be encouraged.

  12. Nifs and Sufs in malaria. (United States)

    Ellis, K E; Clough, B; Saldanha, J W; Wilson, R J


    This review assembles data from three bodies of literature (bacterial genetics, plastid biogenesis and parasitology) that seldom have much direct cross-talk. After overcoming terminological complications to sort out microbial nifS from sufS genes, we connect a bacterial operon, recently found to be involved in iron metabolism, the formation of [Fe-S] clusters and oxidative stress to a potentially important gene (sufB) carried on the degenerate plastid genome of malaria and related parasites.

  13. [Microbiological diagnosis of imported malaria]. (United States)

    Torrús, Diego; Carranza, Cristina; Manuel Ramos, José; Carlos Rodríguez, Juan; Rubio, José Miguel; Subirats, Mercedes; Ta-Tang, Thuy-Huong


    Current diagnosis of malaria is based on the combined and sequential use of rapid antigen detection tests (RDT) of Plasmodium and subsequent visualization of the parasite stained with Giemsa solution in a thin and thick blood smears. If an expert microscopist is not available, should always be a sensitive RDT to rule out infection by Plasmodium falciparum, output the result immediately and prepare thick smears (air dried) and thin extensions (fixed with methanol) for subsequent staining and review by an expert microscopist. The RDT should be used as an initial screening test, but should not replace microscopy techniques, which should be done in parallel. The diagnosis of malaria should be performed immediately after clinical suspicion. The delay in laboratory diagnosis (greater than 3 hours) should not prevent the initiation of empirical antimalarial treatment if the probability of malaria is high. If the first microscopic examination and RDT are negative, they must be repeated daily in patients with high suspicion. If suspicion remains after three negative results must be sought the opinion of an tropical diseases expert. Genomic amplification methods (PCR) are useful as confirmation of microscopic diagnosis, to characterize mixed infections undetectable by other methods, and to diagnose asymptomatic infections with submicroscopic parasitaemia.

  14. The efficiency of malaria chemoprophylaxis

    Directory of Open Access Journals (Sweden)

    Vasiliki Pappa


    Full Text Available Introduction: Malaria is a highly contagious disease. According to WHO, malaria cases are expected to increase due to climate changes. Despite the eradication efforts, malaria still remains one of the most significant causes of morbidity and mortality in tropical and subtropical regions. Many different antimalarial regimens are used , however resistance is emerging to many of themPurpose: This critical review was conducted, in order to respond to the following questions. A Which antimalarial regimen is most effective? B Which regimen is the safest for travelers in endemic regions? C Which regimen is best tolerated?Methodology: The literature research was conducted through the Internet. The Medline and Cinahl databases were used, as well as the search engines google, altavista and lycos. The research included articles that described clinical trials. The material was selected based on the aforementioned research questions and the chronological time limits.Results: Atovaquone/proguanil, tafenoquine, primaquine were the most effective regimens. Tafenoquine, as well as, primaquine have been related to hemolytic events in individuals with G6PD deficiency, gastrointestinal disorders, backache and flue-like syndrome. Doxycycline and mefloquine were related to gastrointestinal and neurological disorders. Those were the less tolerated regimens.Conclusions: Atovaquone/proguanil, tafenoquine, primaquine were the most effective regimens. As far as safety is concerned, tafenoquine and primaquine should not be prescribed to individuals with G6PD deficiency. All the regimens were considered well tolerated, however, in doxycycline and mefloquine trials were the most withdrawals due to adverse effects.

  15. Electrochemical impedance spectroscopy to study physiological changes affecting the red blood cell after invasion by malaria parasites. (United States)

    Ribaut, Clotilde; Reybier, Karine; Reynes, Olivier; Launay, Jérôme; Valentin, Alexis; Fabre, Paul Louis; Nepveu, Françoise


    The malaria parasite, Plasmodium falciparum, invades human erythrocytes and induces dramatic changes in the host cell. The idea of this work was to use RBC modified electrode to perform electrochemical impedance spectroscopy (EIS) with the aim of monitoring physiological changes affecting the erythrocyte after invasion by the malaria parasite. Impedance cell-based devices are potentially useful to give insight into cellular behavior and to detect morphological changes. The modelling of impedance plots (Nyquist diagram) in equivalent circuit taking into account the presence of the cellular layer, allowed us pointing out specific events associated with the development of the parasite such as (i) strong changes in the host cell cytoplasm illustrated by changes in the film capacity, (ii) perturbation of the ionic composition of the host cell illustrated by changes in the film resistance, (iii) releasing of reducer (lactic acid or heme) and an enhanced oxygen consumption characterized by changes in the charge transfer resistance and in the Warburg coefficient characteristic of the redox species diffusion. These results show that the RBC-based device may help to analyze strategic events in the malaria parasite development constituting a new tool in antimalarial research.

  16. O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin is limited by nitrogen monoxide dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Ascenzi, Paolo, E-mail: [Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy); National Institute for Infectious Diseases I.R.C.C.S. ' Lazzaro Spallanzani' , Via Portuense 292, I-00149 Roma (Italy); Gullotta, Francesca; Gioia, Magda; Coletta, Massimo [Department of Experimental Medicine and Biochemical Sciences, University of Roma ' Tor Vergata' , Via Montpellier 1, I-00133 Roma (Italy); Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Piazza Umberto I 1, I-87100 Bari (Italy); Fasano, Mauro [Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12a, I-21052 Busto Arsizio, VA (Italy)


    Research highlights: {yields} Human serum heme-albumin displays globin-like properties. {yields} O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin. {yields} Allosteric modulation of human serum heme-albumin reactivity. {yields} Rifampicin is an allosteric effector of human serum heme-albumin. {yields} Human serum heme-albumin is a ROS and NOS scavenger. -- Abstract: Human serum heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, kinetics of O{sub 2}-mediated oxidation of ferrous nitrosylated HSA-heme-Fe (HSA-heme-Fe(II)-NO) is reported. Values of the first-order rate constants for O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO (i.e., for ferric HSA-heme-Fe formation) and for NO dissociation from HSA-heme-Fe(II)-NO (i.e., for NO replacement by CO) are k = 9.8 x 10{sup -5} and 8.3 x 10{sup -4} s{sup -1}, and h = 1.3 x 10{sup -4} and 8.5 x 10{sup -4} s{sup -1}, in the absence and presence of rifampicin, respectively, at pH = 7.0 and T = 20.0 {sup o}C. The coincidence of values of k and h indicates that NO dissociation represents the rate limiting step of O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO. Mixing HSA-heme-Fe(II)-NO with O{sub 2} does not lead to the formation of the transient adduct(s), but leads to the final ferric HSA-heme-Fe derivative. These results reflect the fast O{sub 2}-mediated oxidation of ferrous HSA-heme-Fe and highlight the role of drugs in modulating allosterically the heme-Fe-atom reactivity.

  17. Anestesia e paralisia cerebral


    Március Vinícius M Maranhão


    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...

  18. Automated detection of malaria pigment: feasibility for malaria diagnosing in an area with seasonal malaria in northern Namibia

    NARCIS (Netherlands)

    A.J. de Langen; J. van Dillen; P. Witte; S. Mucheto; N. Nagelkerke; P. Kager


    OBJECTIVE To evaluate the feasibility of automated malaria detection with the Cell-Dyn (R) 3700 (Abbott Diagnostics, Santa Clara, CA, USA) haematology analyser for diagnosing malaria in northern Namibia. METHODS From April to June 2003, all patients with a positive blood smear result and a subset of

  19. Climate, environment and transmission of malaria. (United States)

    Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Zaramella, Marco; Caputo, Annamaria; Garavelli, Pietro Luigi


    Malaria, the most common parasitic disease in the world, is transmitted to the human host by mosquitoes of the genus Anopheles. The transmission of malaria requires the interaction between the host, the vector and the parasite.The four species of parasites responsible for human malaria are Plasmodium falciparum, Plasmodium ovale, Plasmodium malariae and Plasmodium vivax. Occasionally humans can be infected by several simian species, like Plasmodium knowlesi, recognised as a major cause of human malaria in South-East Asia since 2004. While P. falciparum is responsible for most malaria cases, about 8% of estimated cases globally are caused by P. vivax. The different Plasmodia are not uniformly distributed although there are areas of species overlap. The life cycle of all species of human malaria parasites is characterised by an exogenous sexual phase in which multiplication occurs in several species of Anopheles mosquitoes, and an endogenous asexual phase in the vertebrate host. The time span required for mature oocyst development in the salivary glands is quite variable (7-30 days), characteristic of each species and influenced by ambient temperature. The vector Anopheles includes 465 formally recognised species. Approximately 70 of these species have the capacity to transmit Plasmodium spp. to humans and 41 are considered as dominant vector capable of transmitting malaria. The intensity of transmission is dependent on the vectorial capacity and competence of local mosquitoes. An efficient system for malaria transmission needs strong interaction between humans, the ecosystem and infected vectors. Global warming induced by human activities has increased the risk of vector-borne diseases such as malaria. Recent decades have witnessed changes in the ecosystem and climate without precedent in human history although the emphasis in the role of temperature on the epidemiology of malaria has given way to predisposing conditions such as ecosystem changes, political

  20. Determinan Kejadian Malaria di Wilayah Endemis

    Directory of Open Access Journals (Sweden)

    Hamzah Hasyim


    Full Text Available Kabupaten Lahat adalah salah satu wilayah endemis malaria di Sumatera Selatan dengan prevalensi 16,4% dan Annual Malaria Incidence 22,08. Tujuan penelitian ini untuk mengetahui faktor risiko lingkungan dengan kejadian malaria. Faktor risiko lingkungan genangan air (breeding place berhubungan dengan kejadian malaria dengan nilai p= 0,000. Analisis multivariat menemukan determinan utama kejadian malaria adalah breeding place di sekitar rumah responden dengan odds ratio (OR = 5,034 dan 95% CI = 2,65 _ 9,56. Responden yang tinggal di sekitar breeding place berisiko 5,03 kali lebih besar untuk menderita malaria dibandingkan dengan responden yang di sekitar rumah tidak terdapat breeding place setelah dikontrol variabel jarak rumah ke breeding place, ventilasi rumah, penggunaan kelambu, penggunaan obat anti nyamuk, dan kebiasaan keluar rumah pada malam hari. Lahat district is one of the malaria endemic area in South Sumatra Province with a prevalence of 16.4% and Annual Malaria Incidence of 22.08. The case control reports were carried out of 240 respondents. This study aimed to understand the relationship among of environmental risk factors with the incidence of malaria. After primary data collection followed by processing and data analysis in a multimedia laboratory. There was association between breeding place and malaria cases (p value= 0.000. The results of multivariate analysis of variables revealed the determinant risk was breeding place, with OR = 5.034 and CI 95%= 2.65 _ 9.56. Respondents who live around the breeding place has 5.034 times chance of affected malaria compared with respondents around the house there are no breeding place after the controlled distance to the breeding place house, use of mosquito nets, use of anti-mosquito, and habits out of the house at night variables.

  1. Associations between maternal helminth and malaria infections in pregnancy, and clinical malaria in the offspring

    DEFF Research Database (Denmark)

    Ndibazza, Juliet; Webb, Emily L; Lule, Swaib


    Background. Helminth and malaria coinfections are common in the tropics. We investigated the hypothesis that prenatal exposure to these parasites might influence susceptibility to infections such as malaria in childhood.Methods. In a birth cohort of 2,345 mother-child pairs in Uganda, maternal...... helminth and malaria infection status was determined during pregnancy, and childhood malaria episodes recorded from birth to age five years. We examined associations between maternal infections and malaria in the offspring.Results. Common maternal infections were hookworm (45%), Mansonella perstans (21......%), Schistosoma mansoni (18%), and Plasmodium falciparum (11%). At age 5 years, 69% of the children were still under follow-up. The incidence of malaria was 34 episodes per 100 child-years, and the mean prevalence of asymptomatic malaria at annual visits was 5.4%. Maternal hookworm and M. perstans infections were...

  2. Rapid induction of heme oxygenase 1 mRNA and protein by hyperthermia in rat brain: heme oxygenase 2 is not a heat shock protein.


    Ewing, J F; Maines, M D


    Catalytic activity of heme oxygenase (heme, hydrogen-donor:oxygen oxidoreductase, EC isozymes, HO-1 and HO-2, permits production of physiologic isomers of bile pigments. In turn, bile pigments biliverdin and bilirubin are effective antioxidants in biological systems. In the rat brain we have identified only the HO-1 isozyme of heme oxygenase as a heat shock protein and defined hyperthermia as a stimulus that causes an increase in brain HO-1 protein. Exposure of male rats to 42 degr...

  3. Reciprocal allosteric modulation of carbon monoxide and warfarin binding to ferrous human serum heme-albumin.

    Directory of Open Access Journals (Sweden)

    Alessio Bocedi

    Full Text Available Human serum albumin (HSA, the most abundant protein in human plasma, could be considered as a prototypic monomeric allosteric protein, since the ligand-dependent conformational adaptability of HSA spreads beyond the immediate proximity of the binding site(s. As a matter of fact, HSA is a major transport protein in the bloodstream and the regulation of the functional allosteric interrelationships between the different binding sites represents a fundamental information for the knowledge of its transport function. Here, kinetics and thermodynamics of the allosteric modulation: (i of carbon monoxide (CO binding to ferrous human serum heme-albumin (HSA-heme-Fe(II by warfarin (WF, and (ii of WF binding to HSA-heme-Fe(II by CO are reported. All data were obtained at pH 7.0 and 25°C. Kinetics of CO and WF binding to the FA1 and FA7 sites of HSA-heme-Fe(II, respectively, follows a multi-exponential behavior (with the same relative percentage for the two ligands. This can be accounted for by the existence of multiple conformations and/or heme-protein axial coordination forms of HSA-heme-Fe(II. The HSA-heme-Fe(II populations have been characterized by resonance Raman spectroscopy, indicating the coexistence of different species characterized by four-, five- and six-coordination of the heme-Fe atom. As a whole, these results suggest that: (i upon CO binding a conformational change of HSA-heme-Fe(II takes place (likely reflecting the displacement of an endogenous ligand by CO, and (ii CO and/or WF binding brings about a ligand-dependent variation of the HSA-heme-Fe(II population distribution of the various coordinating species. The detailed thermodynamic and kinetic analysis here reported allows a quantitative description of the mutual allosteric effect of CO and WF binding to HSA-heme-Fe(II.

  4. Cellular iron depletion weakens induction of heme oxygenase-1 by cadmium. (United States)

    Lai, Chengzhi; Loo, George


    Heme oxygenase-1 is an inducible cytoprotective gene, although its induction by environmental factors is not completely understood. This study aimed to ascertain if specific nutritive factors or related compounds influence heme oxygenase-1 expression. In HCT-116 cells, cadmium increased heme oxygenase-1 enzymatic activity. This effect of cadmium was weaker in cells made iron-deficient with the iron chelator, desferrioxamine, which was associated with repression of heme oxygenase-1 protein and mRNA expression. The repression by desferrioxamine of cadmium-induced heme oxygenase-1 upregulation was reversed upon iron replenishment of the cells. Additionally, it was found that thiol antioxidants inhibited the heme oxygenase-1 upregulation caused by cadmium and also by ethacrynic acid, which each decreased intracellular glutathione as did buthionine sulfoxamine. Interestingly, cadmium and ethacrynic acid increased nuclear translocation of Nrf2 and subsequent heme oxygenase-1 expression, but buthionine sulfoxamine did not. Furthermore, NADPH oxidase inhibitors (diphenyleneiodonium and apocynin, and a superoxide scavenger (Tiron) inhibited cadmium-induced upregulation of heme oxygenase-1. Diphenyleneiodonium was the most potent and inhibited NADPH-cytochrome P450 reductase as well, whereas apocynin and Tiron did not. It is concluded that adequate amounts of iron, which at the atomic level can serve as the pivotal element of heme in NADPH oxidase, must be present in cells to permit what appears to be thiol redox-sensitive, NADPH oxidase-dependent upregulation of heme oxygenase-1. Thus, these findings are significant because they suggest that cells without adequate iron would be unable to fully express the stress gene, heme oxygenase-1, when confronted with the toxic metal, cadmium.

  5. Estimating individual exposure to malaria using local prevalence of malaria infection in the field.

    Directory of Open Access Journals (Sweden)

    Ally Olotu

    Full Text Available BACKGROUND: Heterogeneity in malaria exposure complicates survival analyses of vaccine efficacy trials and confounds the association between immune correlates of protection and malaria infection in longitudinal studies. Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level. METHOD AND FINDINGS: We studied three cohorts (Chonyi, Junju and Ngerenya in Kilifi District, Kenya to assess measures of malaria exposure. Prospective data were available on malaria episodes, geospatial coordinates, proximity to infected and uninfected individuals and residence in predefined malaria hotspots for 2,425 individuals. Antibody levels to the malaria antigens AMA1 and MSP1(142 were available for 291 children from Junju. We calculated distance-weighted local prevalence of malaria infection within 1 km radius as a marker of individual's malaria exposure. We used multivariable modified Poisson regression model to assess the discriminatory power of these markers for malaria infection (i.e. asymptomatic parasitaemia or clinical malaria. The area under the receiver operating characteristic (ROC curve was used to assess the discriminatory power of the models. Local malaria prevalence within 1 km radius and AMA1 and MSP1(142 antibodies levels were independently associated with malaria infection. Weighted local malaria prevalence had an area under ROC curve of 0.72 (95%CI: 0.66-0.73, 0.71 (95%CI: 0.69-0.73 and 0.82 (95%CI: 0.80-0.83 among cohorts in Chonyi, Junju and Ngerenya respectively. In a small subset of children from Junju, a model incorporating weighted local malaria prevalence with AMA1 and MSP1(142 antibody levels provided an AUC of 0.83 (95%CI: 0.79-0.88. CONCLUSION: We have proposed an approach to estimating the intensity of an individual's malaria exposure in the field. The weighted local malaria prevalence can be used as individual marker of

  6. Demonstration of cerebral vessels by multiplane computed cerebral angiotomography

    Energy Technology Data Exchange (ETDEWEB)

    Asari S.; Satch, T.; Sakurai, M.; Yamamoto, Y. (Matsuyama Shimin Hospital, Matsuyama (Japan)); Sadamoto, K.


    1. Cerebral arteries and veins were demonstrated by multiplane computed cerebral angiotomography (combination of axial, modified coronal, half axial (Towne), and semisagittal planes). The vessels which were demonstrated by various planes were as follows: Axial plane: Willis ring, middle cerebral arteries (horizontal and insular portions), anterior cerebral arteries (Horizontal and ascending portions), posterior cerebral arteries, basal vein of Rosenthal, internal cerebral veins (and the subependymal veins which join the ICV), and vein of Galen. Coronal plane: intermal carotid arteries (supraclinoid portion), anterior cerebral arteries (horizontal portion), middle cerebral arteries (horizontal and insular portions), lenticulostriate arteries, basal vein of Rosenthal (and the subependymal veins which join this vessel), internal cerebral veins, and vein of Galen. Half axial plane (Towne projection): basilar artery, vertebral arteries, posterior cerebral arteries, superior cerebellar arteries, middle cerebral arteries (horizontal portion), and anterior cerebral arteries (horizontal and ascending portions). Semisagittal plane: internal carotid artery (supraclinoid portion), posterior communicating artery, posterior carebral artery, superior cerebellar artery, internal cerebral vein, basal vein of Rosenthal, vein of Galen, and straight shinus. 2. A detailed knowledge of normal cerebrovascular structures acquired by computed tomography (CT) is essential in detecting and more precisely localizing lesions such as cerebrovascular disease, neoplasm or abscess, in differentiating these lesions from the normal contrast-enhanced structures, and in understanding the spatial relationship between the mass lesion and the neighboring vessels. In addition, it will be possible to discover such asymptomatic cerebrovascular diseases as non-ruptured aneurysms, arteriovenous malformations, and Moyamoya disease by means of computed cerebral angiotomography.

  7. Cerebral venous sinus thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Renowden, Shelley [Frenchay Hospital, Bristol BS16 1LE (United Kingdom)


    A comprehensive synopsis on cerebral venous thrombosis is presented. It emphasizes the various aetiologies, the wide clinical spectrum and the unpredictable outcome. Imaging techniques and pitfalls are reported and the therapeutic options are discussed. (orig.)

  8. Severe Plasmodium falciparum malaria is associated with circulating ultra-large von Willebrand multimers and ADAMTS13 inhibition.

    LENUS (Irish Health Repository)

    Larkin, Deirdre


    Plasmodium falciparum infection results in adhesion of infected erythrocytes to blood vessel endothelium, and acute endothelial cell activation, together with sequestration of platelets and leucocytes. We have previously shown that patients with severe infection or fulminant cerebral malaria have significantly increased circulatory levels of the adhesive glycoprotein von Willebrand factor (VWF) and its propeptide, both of which are indices of endothelial cell activation. In this prospective study of patients from Ghana with severe (n = 20) and cerebral (n = 13) P. falciparum malaria, we demonstrate that increased plasma VWF antigen (VWF:Ag) level is associated with disproportionately increased VWF function. VWF collagen binding (VWF:CB) was significantly increased in patients with cerebral malaria and severe malaria (medians 7.6 and 7.0 IU\\/ml versus 1.9 IU\\/ml; p<0.005). This increased VWF:CB correlated with the presence of abnormal ultra-large VWF multimers in patient rather than control plasmas. Concomitant with the increase in VWF:Ag and VWF:CB was a significant persistent reduction in the activity of the VWF-specific cleaving protease ADAMTS13 (approximately 55% of normal; p<0.005). Mixing studies were performed using P. falciparum patient plasma and normal pooled plasma, in the presence or absence of exogenous recombinant ADAMTS13. These studies demonstrated that in malarial plasma, ADAMTS13 function was persistently inhibited in a time-dependent manner. Furthermore, this inhibitory effect was not associated with the presence of known inhibitors of ADAMTS13 enzymatic function (interleukin-6, free haemoglobin, factor VIII or thrombospondin-1). These novel findings suggest that severe P. falciparum infection is associated with acute endothelial cell activation, abnormal circulating ULVWF multimers, and a significant reduction in plasma ADAMTS13 function which is mediated at least in part by an unidentified inhibitor.

  9. Severe Plasmodium falciparum malaria is associated with circulating ultra-large von Willebrand multimers and ADAMTS13 inhibition.

    Directory of Open Access Journals (Sweden)

    Deirdre Larkin


    Full Text Available Plasmodium falciparum infection results in adhesion of infected erythrocytes to blood vessel endothelium, and acute endothelial cell activation, together with sequestration of platelets and leucocytes. We have previously shown that patients with severe infection or fulminant cerebral malaria have significantly increased circulatory levels of the adhesive glycoprotein von Willebrand factor (VWF and its propeptide, both of which are indices of endothelial cell activation. In this prospective study of patients from Ghana with severe (n = 20 and cerebral (n = 13 P. falciparum malaria, we demonstrate that increased plasma VWF antigen (VWF:Ag level is associated with disproportionately increased VWF function. VWF collagen binding (VWF:CB was significantly increased in patients with cerebral malaria and severe malaria (medians 7.6 and 7.0 IU/ml versus 1.9 IU/ml; p<0.005. This increased VWF:CB correlated with the presence of abnormal ultra-large VWF multimers in patient rather than control plasmas. Concomitant with the increase in VWF:Ag and VWF:CB was a significant persistent reduction in the activity of the VWF-specific cleaving protease ADAMTS13 (approximately 55% of normal; p<0.005. Mixing studies were performed using P. falciparum patient plasma and normal pooled plasma, in the presence or absence of exogenous recombinant ADAMTS13. These studies demonstrated that in malarial plasma, ADAMTS13 function was persistently inhibited in a time-dependent manner. Furthermore, this inhibitory effect was not associated with the presence of known inhibitors of ADAMTS13 enzymatic function (interleukin-6, free haemoglobin, factor VIII or thrombospondin-1. These novel findings suggest that severe P. falciparum infection is associated with acute endothelial cell activation, abnormal circulating ULVWF multimers, and a significant reduction in plasma ADAMTS13 function which is mediated at least in part by an unidentified inhibitor.

  10. Rodent malaria parasites : genome organization & comparative genomics

    NARCIS (Netherlands)

    Kooij, Taco W.A.


    The aim of the studies described in this thesis was to investigate the genome organization of rodent malaria parasites (RMPs) and compare the organization and gene content of the genomes of RMPs and the human malaria parasite P. falciparum. The release of the complete genome sequence of P. falciparu

  11. A research agenda for malaria eradication: vaccines.

    NARCIS (Netherlands)

    Abdulla, S.; Agre, P.; Alonso, P.L.; Arevalo-Herrera, M.; Bassat, Q.; Binka, F.; Chitnis, C.; Corradin, G.; Cowman, A. F.; Culpepper, J.; Portillo, H. del; Dinglasan, R.R.; Duffy, P.; Gargallo, D.; Greenwood, B.; Guinovart, C.; Hall, B.F.; Herrera, S.; Hoffman, S.; Lanzavecchia, A.; Leroy, O.; Levine, M.M.; Loucq, C.; Mendis, K.; Milman, J.; Moorthy, V.S.; Pleuschke, G.; Plowe, C.V.; Reed, S.; Sauerwein, R.W.; Saul, A.; Schofield, L.; Sinden, R.R.; Stubbs, J.; Villafana, T.; Wirth, D.; Yadav, P.; Ballou, R.; Brown, G.; Birkett, A.; Brandt, W.; Brooks, A.; Carter, T.; Golden, A.; Lee, C.; Nunes, J.; Puijalon, O.; Raphael, T.; Richards, H.; Warren, C.; Woods, C.


    Vaccines could be a crucial component of efforts to eradicate malaria. Current attempts to develop malaria vaccines are primarily focused on Plasmodium falciparum and are directed towards reducing morbidity and mortality. Continued support for these efforts is essential, but if mal

  12. A research agenda for malaria eradication: vaccines. (United States)


    Vaccines could be a crucial component of efforts to eradicate malaria. Current attempts to develop malaria vaccines are primarily focused on Plasmodium falciparum and are directed towards reducing morbidity and mortality. Continued support for these efforts is essential, but if malaria vaccines are to be used as part of a repertoire of tools for elimination or eradication of malaria, they will need to have an impact on malaria transmission. We introduce the concept of "vaccines that interrupt malaria transmission" (VIMT), which includes not only "classical" transmission-blocking vaccines that target the sexual and mosquito stages but also pre-erythrocytic and asexual stage vaccines that have an effect on transmission. VIMT may also include vaccines that target the vector to disrupt parasite development in the mosquito. Importantly, if eradication is to be achieved, malaria vaccine development efforts will need to target other malaria parasite species, especially Plasmodium vivax, where novel therapeutic vaccines against hypnozoites or preventive vaccines with effect against multiple stages could have enormous impact. A target product profile (TPP) for VIMT is proposed and a research agenda to address current knowledge gaps and develop tools necessary for design and development of VIMT is presented.

  13. Malaria vaccines: immunity, models and monoclonal antibodies

    DEFF Research Database (Denmark)

    Hviid, Lars; Barfod, Lea


    Although experts in the field have agreed on the malaria vaccine technology roadmap that should be followed (, the path towards an effective malaria vaccine remains littered with intellectual and practical pot-holes. The animal models that are currently...

  14. Malaria vector control: current and future strategies

    NARCIS (Netherlands)

    Takken, W.; Knols, B.G.J.


    The recently announced call for malaria eradication represents a new page in the history of this disease. This has been triggered by remarkable reductions in malaria resulting from combined application of effective drugs and vector control. However, this strategy is threatened by development of inse

  15. Insecticide Resistance Reducing Effectiveness of Malaria Control

    Centers for Disease Control (CDC) Podcasts


    Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field.  Created: 1/24/2007 by Emerging Infectious Diseases.   Date Released: 3/13/2007.

  16. Plasmodium falciparum Malaria, Southern Algeria, 2007


    Boubidi, Saïd C; Gassen, Ibrahim; Khechache, Yacine; Lamali, Karima; Tchicha, Boualem; Brengues, Cécile; Menegon, Michela; Severini, Carlo; Fontenille, Didier; Harrat, Zoubir


    An outbreak of Plasmodium falciparum malaria occurred in Tinzaouatine in southern Algeria in 2007. The likely vector, Anopheles gambiae mosquitoes, had not been detected in Algeria. Genes for resistance to chloroquine were detected in the parasite. The outbreak shows the potential for an increase in malaria vectors in Algeria.

  17. Combining malaria control with rural electrification

    NARCIS (Netherlands)

    Oria, Prisca A.


    Chapter 1 presents the background information relevant to the subject matter and methods of this thesis. These include the application of social and behavioural sciences in malaria control, the SolarMal project and malaria in Kenya. It also presents the research objective, question and design that i

  18. Acute ischemic cerebral attack


    Franco-Garcia Samir; Barreiro-Pinto Belis


    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...

  19. Hitting Hotspots: Spatial Targeting of Malaria for Control and Elimination

    NARCIS (Netherlands)

    Bousema, T.; Griffin, J.T.; Sauerwein, R.W.; Smith, D.L.; Churcher, T.S.; Takken, W.; Ghani, A.; Drakeley, C.; Gosling, R.


    Current malaria elimination guidelines are based on the concept that malaria transmission becomes heterogeneous in the later phases of malaria elimination [1]. In the pre-elimination and elimination phases, interventions have to be targeted to entire villages or towns with higher malaria incidence u

  20. Pilot-scale tests of HEME and HEPA dissolution process

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, Z.H.; Strege, D.K.


    A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME`s) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsed with process water before its disposal as low-level solid waste. The pilot-scale study reported here