UMLS:C0019693 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UMLS:C0019693 (HIV)
170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The central nervous system (CNS) is often affected by HIV-1 infection. Over 40% of AIDS cases present with neurological symptoms and CNS lesion are detected by anatomical and pathological studies in 80 to 90% of AIDS cases. There may be infections and tumors secondary to the immunodeficiency and pathologies may occur directly due to the neurotropism of the virus. Neurological problems associated with HIV-infection include encephalopathies, myelopathies, neuropathies and myopathies. HIV-1-induced encephalopathy may develop at any stages of HIV-1 infection and affects all risk groups equally. Its frequency worldwide is between 4 and 65% among individuals seropositive for HIV-1. The frequencies reported differ between studies due to differences in sampling methods, geographical factors, diagnostic criteria and investigative methods used. The pathogenesis of HIV-1-associated encephalopathy is not understood, but there are several hypotheses. The involvement of HIV-1 infected macrophages and microglial cells has been demonstrated. Indirect mechanisms such as release of lymphokines (tumor necrosis factor-TNF alpha- and interleukin-1) and neurotoxicity of the HIV envelope protein, gp 120, have also been suggested. This disorder is known as HIV-1-associated cognitive and motor syndrome. It presents clinically as a form of sub-cortical dementia with cognitive problems, motor deficits and behavioral disorders depending on the type and stage of HIV infection. The diagnosis can only be made after all other infections and tumors common in HIV-1 patients have been ruled out by appropriate investigations such as cerebrospinal fluid analysis, cerebral scan and magnetic resonance imaging. Electrophysiological studies, such as evoked responses and electroencephalograms, are particularly useful in its diagnosis. Anatomical examination shows diffuse paleness of the white matter, multi-nucleated giant cells and microglial nodes. Neuropsychological studies could be of value in diagnosis and in assessing the response to anti-retroviral treatment. There is currently no specific therapy for HIV-1-associated cognitive and motor syndrome. The use of new nucleoside analogue drugs in combination with existing drugs may provide new approaches to managing these patients.
...
PMID:[HIV-1 cognitive and motor syndrome]. 929 10

Early HIV-1 invasion of the central nervous system has been demonstrated by many cerebrospinal fluid studies; however, most HIV-1 carriers remain neurologically unimpaired during the so-called "asymptomatic" period lasting from seroconversion to symptomatic AIDS. Therefore, very few neuropathological studies have been conducted in the early pre-AIDS stages, and the natural history of central nervous system changes in HIV-1 infection remains poorly understood. Examination of brains of asymptomatic HIV-1 positive individuals who died accidentally and of rare cases with acute fatal encephalopathy revealing HIV infection, and comparison with experimental simian immunodeficiency virus and feline immunodeficiency virus infections suggest that, invasion of the CNS by HIV-1 occurs at the time of primary infection and induces an immunological process in the central nervous system. This includes an inflammatory T-cell reaction with vasculitis and leptomeningitis, and immune activation of brain parenchyma with increased number of microglial cells, upregulation of major histocompatibility complex class II antigens and local production of cytokines. Myelin pallor and gliosis of the white matter are usually found and are likely to be the consequence of opening of the blood-brain barrier due to vasculitis; direct damage to oligodendrocytes by cytokines may also be involved. These white matter changes may explain, at least partly, the early cerebral atrophy observed, by magnetic resonance imaging, in asymptomatic HIV-1 carriers. In contrast, cortical damage seems to be a late event in the course of HIV-1 infection. There is no significant neuronal loss at the early stages of the disease, no accompanying increase in glial fibrillary acid protein staining in the cortex, and only exceptional neuronal apoptosis. Although HIV-1 proviral DNA may be demonstrated in a number of brains, viral replication remains very low during the asymptomatic stage of HIV-1 infection. This makes it likely that, although opening of the blood brain barrier may facilitate viral entry into the brain, specific immune responses including both neutralising antibodies and cytotoxic T-lymphocytes, continuously inhibit viral replication at this stage.
...
PMID:[Central nervous system lesions in the early stages of HIV infection]. 938 1

The brains of six infants 14-34 months of age and with microencephaly (brain weight deficit 20-55.5%) were chosen from a group of cases vertically infected with HIV. The center of our investigations was focused on the white matter changes of which two types were observed in the examined brains. Within the periventricular white matter of four cases evident lesions consisting of myelin pallor and concomitant gliosis were recognized as HIV-1 infection related leukoencephalopathy. In all those cases myelination delay was also noted. In one case HIV encephalitis was diagnosed. Our observations suggest that in the majority of HIV infected infants changes resulting in the brain "too small for age" corelate with myelination delay coexisting with early-onset leukoencephalopathy. Because of the small number of cases in this study the results should be considered preliminary, and will require further investigations.
...
PMID:The white matter changes in microencephalic HIV infected infants. A preliminary report. 959 48

Early HIV-1 invasion of the central nervous system has been demonstrated by many cerebrospinal fluid studies; however, most HIV-1 carriers remains neurologically unimpaired during the so called "asymptomatic" period lasting from seroconversion to symptomatic AIDS. Therefore, there are very few neuropathological studies in the early pre-AIDS stages and the natural history of central nervous system changes in HIV-1 infection remains poorly understood. Examination of brains of asymptomatic HIV-1 positive individuals who died accidentally and of rare cases with acute fatal encephalopathy revealing HIV infection, and comparison with experimental simian immunodeficiency virus and feline immunodeficiency virus infections suggest that invasion of the CNS by HIV-1 occurs at the time of primary infection and induces an immunological process in the central nervous system. This includes an inflammatory T-cell reaction with vasculitis and leptomeningitis, and immune activation of brain parenchyma with increased number of microglial cells, upregulation of major histocompatibility complex class II antigens and local production of cytokines. Myelin pallor and gliosis of the white matter are usually found are likely to be the consequence of opening of the blood brain barrier due to vasculitis; direct damage to oligodendrocytes by cytokines may also interfere. These white matter changes may explain, at least partly, the early cerebral atrophy observed, by magnetic resonance imaging, in asymptomatic HIV-1 carriers. In contrast, cortical damage seems to be a late event in the course of HIV-1 infection. There is no significant neuronal loss at the early stages of the disease, no accompanying increase in glial fibrillary acid protein staining in the cortex, and only exceptional neuronal apoptosis. Although HIV-1 proviral DNA may be demonstrated in a number of brains, viral replication remains very low during the asymptomatic stage of HIV-1 infection. This makes it likely that, although opening of the blood brain barrier may facilitate viral entry into the brain, specific immune responses including both neutralising antibodies and cytotoxic T-lymphocytes, continuously inhibits viral replication at that stage.
...
PMID:[Lesions of the central nervous system in the early stages of human immunodeficiency virus infection]. 968 50

A 38-year-old homosexual male with AIDS suffered four neurological episodes including headaches, confusion, visual impairment, memory disturbances, and dysarthria which resolved spontaneously in a few days. He was admitted to hospital during a fifth episode. Neurological examination revealed a cerebellar syndrome. General examination was normal. CD4 count was 90. CSF contained two WBCs/mm(3) and 12.30 mg/dL protein. MRI revealed diffuse ill defined increased signal on T2-weighted images in the white matter. His condition worsened rapidly with vomiting and he died 1 month after admission. Neuropathological examination revealed diffuse brain oedema with ventricular compression, central diencephalic herniation and bilateral tonsilar herniation in the absence of a focal lesion. Microscopical examination revealed predominant involvement of the white matter with diffuse myelin pallor and massive perivascular dilatation containing an exudate expressing serum proteins and occasional macrophages. The same exudate was also diffuse in the leptomeninges. Parenchymal damage predominated around the perivascular spaces and included loosening of tissue, axonal damage with spheroids and reactive astrocytosis. There was no evidence of productive HIV encephalitis, no multinucleated giant cells; p24 immunostaining and RT-PCR for HIV genome were negative. There was neither significant inflammation nor microglial activation. In this illustrative case, the relapsing course of the neurological signs, the diffuse topography of the blood-brain barrier breakdown and the absence of local cause make it likely that the diffuse leak and axonal damage could be related to circulating factors.
...
PMID:Acute, relapsing brain oedema with diffuse blood-brain barrier alteration and axonal damage in the acquired immunodeficiency syndrome. 971 86

HIV-associated neurological manifestations: dementia, myelopathy, and neuropathy, have become one of the commonest causes of neurological disorders in young people. Cognitive impairment develops in about 30 p. 100 of patients with AIDS and frank dementia in 15 to 20 p. 100 with an annual incidence after AIDS of approximatively 7 p. 100. Typically, the onset of dementia is relatively abrupt over a few weeks or months. The clinical manifestations of the encephalopathy now termed "HIV-dementia", suggest predominant subcortical or frontal involvement. Typical presentation includes apathy and inertia, memory loss and cognitive slowing, minor depressive symptoms and withdrawal from usual activities. Neurological examination may show hypertonia of lower limbs, tremor, clonus, frontal release signs and hyperactive reflexes. Terminally, the patient is bedbound, incontinent, abulic or mute with decorticate posturing leading to death over 3 to 6 months. However, a stabilisation and even a regression of the cognitive disorders have been observed following antiretroviral treatment. Radiological features of HIV dementia include both central and cortical atrophy and white matter rarefaction. However they are neither invariable nor specific. Together with CSF examination, they are more important to exclude opportunistic infections. Indeed, although a completely normal CSF profile may reasonably exclude the diagnosis; at present, no single test or combination of tests can reliably diagnose HIV dementia. Although the clinical characteristics of HIV-dementia are now clearly established, its pathogenesis is unclear and its pathological counterpart remains a matter of debate. A number of "HIV-induced" lesions may be found in the brain of AIDS patients and their causative role in HIV-dementia has been considered. They include HIV encephalitis due to productive CNS infection by the virus, diffuse white matter pallor "HIV-leukoencephalopathy" reflecting an abnormality of the blood brain barrier, involvement of the grey matter, "diffuse poliodystrophy", with neuronal loss that results, at least partly, from a process of programmed cell death and axonal damage. These changes are variably associated in patients with HIV dementia, however none of them can be closely related to the cognitive disorders. This suggests that the neuronal dysfunction underlying HIV-dementia results from different mechanisms that are variably associated and may interact mutually. These include production of viral proteins, microglial activation with consequent production of neurotoxic factors such as proinflammatory cytokines, free radicals, derivates of arachidonic acid, or quinoleic acid, and blood borne neurotoxic factors in particular cytokines.
...
PMID:[Dementia and human inmmunodeficiency virus infection]. 983 49

A retrospective study of all children admitted with the diagnosis of acquired immunodeficiency syndrome (AIDS) at Jos University Teaching Hospital (JUTH) between August 1995 and October 1996 was carried out. Forty three (1.5% out of a total of 2793 children were diagnosed with HIV infection during the study period. However, only the records of 23 out. Of the 43 positive cases were available for analysis. Of the 23 cases whose records were available, 8 presented in 1995, while the remaining 15 presented between January and October 1996. The ages of the children ranged between 1 and 15 years (Mean 3.0 +/- 4.1 Years). There were 12 males and 11 females (M:F = 1:1). Sixteen (69.6 percent) out of the 23 patients were aged between 1 month and 2 years. Sixteen (69.6%) of the 23 patients acquired the infection vertically, 2 (8.9%) acquired the infection through blood transfusion, 1 (4.3%) from sexual abuse, while in 4 (17.4%) the source of infection could not be established due to inadequate data. Majority of the children presented with weight loss, chronic diarrhoea and fever, while the common findings included wasting, oralthrush, pallor, hepatosplenomegaly and lymphadenopathy. Six (26.1 percent) out of the 23 children died, 8 (34.8 percent) were discharged against medical advice and have not been seen since, 9 (39.1%) improved and were discharged to out-patient clinic followup, but all except 2 of these have been lost to follow-up. It is concluded that AIDS is increasingly becoming a major cause of childhood morbidity and mortality in our environment. All children in our environment who present with features of malnutrition should be screened for AIDS. Campaigns aimed at preventing vertical (maternal-child) transmission, including health education of young men and women on the risk of unprotected sex must be vigorously pursued and sustained.
...
PMID:Paediatric AIDS in Jos, Nigeria. 992 Oct 95

Serum protein levels in LP-BM5 infected mouse brains were investigated to gain insight into the contribution of blood-brain barrier (BBB) patency to the pathogenesis of retroviral encephalopathy. Evans blue uptake by the forebrain and cerebellum was significantly increased between 8-12 weeks post inoculation. Immunohistochemistry revealed foci of albumin, transferrin, alpha(2)-macroglobulin and IgG transudation around blood vessels particularly in the cerebral cortex and cerebellar vermis. These leaks were often associated with astrocytosis and apoptotic cells. Unlike the other serum proteins, IgG immunoreactivity extended from the circumventricular organs and disseminated throughout the brain parenchyma, accumulating on the plasma membranes of hippocampal and cortical neurons. Consistent with the chronic elevation of free glutamate levels in LP-BM5 infected mice, the increase in Evans blue uptake into the forebrain was completely reversed following dizocilpine administration. Thus, the chronic increase in free glutamate levels in LP-BM5 infected mouse brain contributes to BBB disruption. Furthermore, the CNS accumulation of serum proteins, particularly IgG, observed in these mice may increase osmotic load, impair neuronal function, and cause white matter pallor. Administration of NMDA receptor antagonists may prove useful in managing BBB permeability in those neuropathologies, such as HIV-associated dementia/cognitive/motor complex, having a glutamatergic component.
...
PMID:Increased blood-brain barrier permeability in LP-BM5 infected mice is mediated by neuroexcitatory mechanisms. 1048 8

Diffuse white matter pallor is the most frequent neuropathological feature of HIV-1 infection and has been found to be particularly prominent in the advanced stages of the disease. The purpose of this study was to determine whether subtle white matter abnormalities can be detected in medically stable, ambulatory HIV-1 patients, in vivo, using diffusion tensor imaging (DTI). DTI is a magnetic resonance imaging (MRI) technique that is uniquely suited for the study of subtle white matter abnormalities. DTI was performed in six HIV-1 patients and nine controls. The two groups were similar in age. Abnormal fractional anisotropy was found in the white matter of the frontal lobes and internal capsules of the HIV-1 patients, in the absence of group differences in mean diffusivity, computed proton density, and computed T2. DTI may be more sensitive than conventional MRI methods for detecting subtle white matter disruptions in HIV-1 disease.
...
PMID:White matter abnormalities in HIV-1 infection: a diffusion tensor imaging study. 1123 Oct 96

HIV infection is associated with a number of blood abnormalities. Anemia is a frequent consequence, affecting 15 percent of asymptomatic HIV-positive individuals and 85 percent of those with AIDS. Anemia is defined by a decreased number of red blood cells. Individuals with anemia have a diminished capacity to carry oxygen in their blood and suffer from fatigue, difficulty breathing, increased heart rate, pallor, and occasionally heart murmurs. Treatment depends on the underlying cause of anemia.
...
PMID:Anemia in HIV disease. 1136 15

<< Previous 1 2 3 4 5 6 7 Next >>