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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CBA/Ca mice injected with Plasmodium berghei develop cerebral malaria (CM) characterized by ataxia and progressive paralysis leading to death 7-9 days after experimental infection. The development of cerebral symptoms is a function of the immune response in susceptible strains, and depends on cell-cell interactions involving T helper cells and mononuclear phagocytes. Here we ask whether antibodies to cell adhesion receptors of the immune system can influence the development of CM in this mouse model. When administrated on day 6 after infection, antibody to the leukocyte integrin leukocyte function-antigen-1 (LFA-1) but not antibodies to MAC-1, LECAM-1 (the MEL-14 antigen), alpha 4 integrin or ICAM-1 dramatically reduced the incidence of CM, leading to survival of most mice until the later onset of anemia. Anti-LFA-1 treatment did not result in a substantial decrease in the monocyte accumulation observed in cerebral vessels of susceptible mice. Its efficacy may be related to the broader roles of LFA-1 in cell-cell interactions important in the later pathogenic stages of the immune response to the parasite. Perturbation of immune cell function through interference with cell adhesion mechanisms may offer an important therapeutic tool in acute, life-threatening immune-mediated disorders.
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PMID:Late treatment with anti-LFA-1 (CD11a) antibody prevents cerebral malaria in a mouse model. 167 16

Out of 604 Gambian children admitted with falciparum malaria to one hospital between September and December, 1988, 308 had cerebral malaria and 203 were severely anaemic (haemoglobin less than 60 g/l). 14% of those with cerebral malaria died, as did 7.8% of those with severe anaemia. 32 (12%) of children surviving cerebral malaria had residual neurological deficit. 69 other children were admitted with clinical features strongly suggestive of cerebral malaria but with negative blood films; 16 of these died and 3 had residual neurological deficits. The commonest sequelae of cerebral malaria were hemiplegia (23 cases), cortical blindness (11), aphasia (9), and ataxia (6). Factors predisposing to sequelae included prolonged coma, protracted convulsions, severe anaemia, and a biphasic clinical course characterised by recovery of consciousness followed by recurrent convulsions and coma. At follow up 1-6 months later over half these children had made a full recovery, but a quarter were left with a major residual neurological deficit. Cerebral malaria in childhood may be an important cause of neurological handicap in the tropics.
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PMID:Neurological sequelae of cerebral malaria in children. 197 27

Twelve cases of an unusual phenomenon of ataxia were investigated in otherwise well, conscious patients recovering from a febrile attack of presumed falciparum malaria. The ataxia occurred as the fever was subsiding, usually after an afebrile period of two to four days. The delay between onset of fever and the ataxia was three to four weeks. Peripheral blood of all the patients contained gametocytes of Plasmodium falciparum, and in some cases ring stages. The ataxia was most noticeable in the legs and the clinical picture suggested selective impairment of the cerebellar system. Signs of improvement appeared in a few weeks but complete recovery took one to four months. The most likely pathogenic mechanism of the ataxia in these cases was an immune reaction triggered by the malaria parasite and affecting the cerebellum or its connections, or both.
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PMID:Delayed cerebellar ataxia: a new complication of falciparum malaria? 310 3

The currently recognized toxic effects of quinine in humans are identified and the problems of management of overdosage of quinine are discussed. Quinine, available therapeutically as sulphate or hydrochloride salts, also is widely used in tonic water, and there are several case reports of allergic reactions to the drug when a patient has consumed the drug in this way. Another unintentional source of poisoning is its use as an adulterant in heroin for "street" use. This appears to be a problem in the US. Quinine, termed a "general protoplasmic poison" is toxic to many bacteria, yeasts, and trypanosomes, as well as to malarial plasmodia. Quinine has local anesthetic action but also is an irritant. The irritant effects may be responsible in part for the nausea associated with its clinical use. In addition it has a mild antipyretic effect. Several features are common to both an acute single overdose in self-poisoning and accumulation of quinine during therapy for malaria: together they are termed cinchonism. Auditory symptoms, gastrointestinal disturbances, vasodilatation, sweating, and headache occur with moderately elevated plasma quinine concentration. As these rise, increasingly severe visual disturbances and then cardiac and neurologic features occur. Mild nausea may be the only symptom, but with large overdoses profuse vomiting, abdominal pain, and diarrhea may occur. These result from a combination of the local irritant effect of quinine on the gut and the central effects of quinine on the chemoreceptor trigger zone. Vasodilatation and sweating are well recognized, and tinnitus is common. Visual symptoms usually are delayed, and blindness may not be discovered for a day or more. Aspirin-sensitive patients, and others, may develop angioedema by nonimmunological mechanisms in response to drugs, and quinine has been reported to produce pseudo-allergic reactions in aspirin-sensitive patients. Quinine also can cause drug-induced thrombocytopenia and purpura. In patients suffering with malaria due to "Plasmodium falciparum," anemia and acute intravascular hemolysis with renal failure are recognized complications. There appears to be little evidence in the literature in support of the folk tradition of quinine as an inducer of abortion. Quinine is known to cause deterioration in patients with myasthenia gravis and erythema multiforme, to stimulate insulin release in patients receiving treatment for falicparum malaria, and to be responsible at times for ataxia following moderate overdosage. Clinically, quinine poisoning is observed in 3 situations: self-poisoning; accidentally; and following use of quinine in excessive doses in the hope of achieving abortion. Treatment courses are reviewed.
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PMID:Quinine toxicity. 354 70

The course of lethal Plasmodium berghei infection was examined in nu/+ and T cell-deficient nu/nu BALB/c mice. A rapidly fatal neurologic syndrome, including ataxia, hemiparesis, and seizures, was seen in the nu/+ mice early in the infection, whereas this syndrome was absent in the nu/nu mice. The nu/nu mice also developed anemia more slowly, had lower levels of immune complexes and total IgG, and had smaller decreases in serum C3 compared with the nu/+ mice. Histopathologic examination of the brains revealed cerebral malaria lesions, including vascular plugging and micro-hemorrhages, in the nu/+ mice but not in the nu/nu mice. Cerebral lesions similar in frequency and severity to those in nu/+ mice developed in nu/nu mice given spleen cells from normal nu/+ mice. The results suggest that an intact immune system is necessary for the expression of cerebral malaria.
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PMID:Virulent P. berghei malaria: prolonged survival and decreased cerebral pathology in cell-dependent nude mice. 674 88

Cytokines are now recognized to play important roles in the physiology of the central nervous system (CNS) during health and disease. Tumor necrosis factor alpha (TNF-alpha) has been implicated in the pathogenesis of several human CNS disorders including multiple sclerosis, AIDS dementia, and cerebral malaria. We have generated transgenic mice that constitutively express a murine TNF-alpha transgene, under the control of its own promoter, specifically in their CNS and that spontaneously develop a chronic inflammatory demyelinating disease with 100% penetrance from around 3-8 weeks of age. High-level expression of the transgene was seen in neurons distributed throughout the brain. Disease is manifested by ataxia, seizures, and paresis and leads to early death. Histopathological analysis revealed infiltration of the meninges and CNS parenchyma by CD4+ and CD8+ T lymphocytes, widespread reactive astrocytosis and microgliosis, and focal demyelination. The direct action of TNF-alpha in the pathogenesis of this disease was confirmed by peripheral administration of a neutralizing anti-murine TNF-alpha antibody. This treatment completely prevented the development of neurological symptoms, T-cell infiltration into the CNS parenchyma, astrocytosis, and demyelination, and greatly reduced the severity of reactive microgliosis. These results demonstrate that overexpression of TNF-alpha in the CNS can cause abnormalities in nervous system structure and function. The disease induced in TNF-alpha transgenic mice shows clinical and histopathological features characteristic of inflammatory demyelinating CNS disorders in humans, and these mice represent a relevant in vivo model for their further study.
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PMID:Spontaneous inflammatory demyelinating disease in transgenic mice showing central nervous system-specific expression of tumor necrosis factor alpha. 747 82

We report the clinical features of 74 patients with delayed cerebellar ataxia (DCA) following falciparum malaria, who were prospectively followed up at two centres. This unusual complication has an acute onset, with signs suggesting a predominantly midline cerebellar lesion without any evidence of cerebral involvement. There was a delay of a median 13 days between the onset of fever and the onset of ataxia. DCA has a good prognosis, with spontaneous and complete recovery within 3 months. In our opinion, it is an example of a post-infective neurological syndrome possibly mediated via an immune mechanism.
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PMID:Delayed cerebellar ataxia complicating falciparum malaria: a clinical study of 74 patients. 793 48

This study was carried out on 170 children admitted to the University Hospital of Brazzaville (Congo) for cerebral malaria between January 1, 1988 and June 30, 1989. The selection criteria were 1) unarousable coma, cerebrospinal fluid without microorganisms or a marked cellular reaction, and the absence of other causes, and 2) that the children lived in Brazzaville. The case fatality rate was 15%. In 75% of the cases, death occurred within the first 48 hr. The prognosis worsened with the stage of the coma and a younger age. At discharge from the hospital, 9% of the cases presented with sequelae. The postcerebral malaria mortality was high; indeed, death occurred in six (7%) of 90 children discharged from the hospital whose parents were contacted between nine and 27 months later. Two deaths were directly related to neurologic sequelae. Among the 58 children examined under satisfactory conditions between nine and 27 months (mean 16.9 months) after discharge, 50% (3 of 6) still presented with attenuated forms of the sequelae observed immediately after the episode of cerebral malaria (cortical blindness had regressed completely, unlike ataxia and loss of balance). Disorders that may have been related to the episode of cerebral malaria were observed in 31% of these 58 cases.
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PMID:Mortality and sequelae due to cerebral malaria in African children in Brazzaville, Congo. 844 26

The pathogenesis of human cerebral malaria (CM) remains unresolved. In the most widely used murine model of CM, the presence of T lymphocytes and/or interferon (IFN)-gamma is a prerequisite. IFN-gamma is the key inducer of indoleamine 2,3-dioxygenase (IDO), which is the catalyst of the first, and rate-limiting, step in the metabolism of tryptophan (Trp) along the kynurenine (Kyn) pathway. Quinolinic acid (QA), a product of this pathway, is a neuro-excitotoxin, like glutamic acid (Glu) and aspartic acid (Asp). Kynurenic acid (KA), also produced from the Kyn pathway, antagonizes the neuro-excitotoxic effects of QA, Glu, and Asp. We therefore examined the possible roles of IDO, metabolites of the Kyn pathway, Glu, and Asp in the pathogenesis of fatal murine CM. Plasmodium berghei ANKA infection was studied on days 6 and 7 post-inoculation (p.i.), at which time the mice exhibited cerebral symptoms such as convulsions, ataxia, coma, and a positive Wooly/White sign and died within 24 hours. A model for noncerebral malaria (NCM), P. berghei K173 infection, was also studied on days 6 and 7 and 13 to 17 p.i. to examine whether any changes were a general response to malaria infection. Biochemical analyses were done by high-pressure liquid chromatography and gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS). IDO activity was low or absent in the brains of uninfected mice and NCM mice (days 6 and 7 p.i.) and was induced strongly in the brains of fatal murine CM mice (days 6 and 7 p.i.) and NCM animals (days 13 to 17 p.i.). This induction was inhibited greatly by administration of dexamethasone, a treatment that also prevented CM symptoms and death. Furthermore, IDO induction was absent in IFN-gamma gene knockout mice, which were also resistant to CM. Brain concentrations of Kyn, 3-hydroxykynurenine, and the neuro-excitotoxin QA were significantly increased in both CM mice on days 6 and 7 p.i. and NCM mice on days 13 to 17 p.i., whereas an increase in the ratio of brain QA to KA occurred only in the CM mice at the time they were exhibiting cerebral symptoms. Brain concentrations of Glu and Asp were significantly decreased in CM and NCM mice (days 13 to 17 p.i.). The results imply that neuro-excitation induced by QA may contribute to the convulsions and neuro-excitatory signs observed in CM.
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PMID:Dramatic changes in oxidative tryptophan metabolism along the kynurenine pathway in experimental cerebral and noncerebral malaria. 946 88

In this study the clinical manifestation and the effect of corticosteroids on the course and the outcome of post malaria cerebellar ataxia on thirty adult Sudanese patients wr investigated. Twenty four patients with delayed ataxia, that is, ataxia occurring shortly after full recovery from otherwise uncomplicated, documented malaria and six patients who were found to be ataxic on recovery from cerebral malaria were included in the study. The distribution of the age, sex and various clinical aspects were outlined. Twelve randomly selected patients were given oral prednisolone. The corticosteroid was found to shorten the period of ataxia. It was also found that in patients who demonstrated cerebellar infarction or atrophy on computerised tomography the duration of ataxia was significantly long.
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PMID:Post-malarial cerebellar ataxia in adult Sudanese patients. 948 32


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