Neurological complications of acquired immune deficiency syndrome: analysis of 50 patients

Development and testing of AIDS vaccines

Recent advances in delineating the molecular biology of human immunodeficiency virus type 1 (HIV-1) have led to innovative approaches to development of a vaccine for acquired immunodeficiency syndrome (AIDS). However, the lack of understanding of mechanisms of protective immunity against HIV-1, the magnitude of genetic variation of the virus, and the lack of effective animal models for HIV-1 infection and AIDS have impeded progress. The testing of AIDS vaccines also presents challenges. These include liability concerns over vaccine-related injuries; identification of suitable populations for phase 3 efficacy studies; balancing the ethical obligation to counsel research subjects to avoid high-risk behavior with the necessity to obtain vaccine efficacy data; and the effect of vaccine-induced seroconversion on the recruiting and welfare of trial volunteers. Several candidate AIDS vaccines are nevertheless currently under development, and some are undergoing phase 1 clinical trials. Rapid progress will depend on continued scientific advancement in conjunction with maximum use of resources, open information and reagent exchange, and a spirit of international collaboration.

Value of necropsy in acquired immunodeficiency syndrome

Necropsy findings in 101 adult patients with the acquired immunodeficiency syndrome (AIDS) from two metropolitan hospitals were compared retrospectively with the antemortem clinical diagnoses. 94% of the patients were male and 68% were homosexual or bisexual. 75 (74%) patients had AIDS-related diseases at necropsy that were not suspected clinically. The commonest of the unsuspected AIDS-related diseases were cytomegalovirus infection (49% of all cases), systemic fungal infection (20%), systemic Kaposi's sarcoma (14%), Mycobacterium avium intracellulare infection (11%), and systemic herpes infection (9%). Cryptococcal infection and cytomegalovirus retinitis were always diagnosed antemortem; and Pneumocystis carinii pneumonia went undiagnosed in only 5 of 58 (9%) patients who had proven infection either clinically or at necropsy. 8 patients who died with fungal pneumonia had undergone bronchoscopy; however, in only 1 patient was it diagnosed antemortem. Tuberculosis was undiagnosed in 4 patients. 4 cases of central nervous system lymphoma diagnosed only at necropsy had been treated empirically for toxoplasmosis. Bacterial pneumonias contributed considerably to mortality in 30% of the patients.

Cognitive changes as early signs of HIV infection

Neuropsychological examination was performed on 13 patients and 10 matched controls to assess the brain involvement of patients with human immunodeficiency virus (HIV) infection. HIV-infected patients showed a significant decline in visuomotor, visuoconstructive and practical abilities as well as in motor-free visuospatial performance and repeating a long sentence. These findings could not be explained by the concomitant mental depression of these patients. Neither were they associated with any particular stage of HIV infection. The results suggest that mild cognitive changes may be detected even in the early stages of HIV infection, when examined by appropriate neuropsychological methods.

Human immunodeficiency virus infection of the brain. I. Virus isolation and detection of HIV specific antibodies in the cerebrospinal fluid of patients with varying clinical conditions

Isolation of the human immunodeficiency virus (HIV) has been attempted from the cerebrospinal fluid (CSF) of 29 subjects with varying severity of HIV infection. Virus could be isolated from patients in all stages of disease including patients with primary HIV infection and asymptomatic carriers. In the early stages of infection free virus was infrequently present in the CSF but could be isolated from the cells present in CSF. This suggests that HIV may reach the brain at a very early stage of infection and that initially there is little production of virus from infected cells. In the late stages of HIV infection, associated with increasing severity of immunodeficiency, free virus could readily be isolated from the CSF. With one exception, all of these patients had neurological and/or psychiatric symptoms, as compared to only 2 (of 13) subjects in the early stages of infection. All patients with HIV-specific antibodies in serum had antibodies also in CSF. Examined by a radioimmunoprecipitation assay, CSF was more often found to contain antibodies to the precursor (p55) of viral core proteins than the corresponding serum of the patients. We propose that immune disturbances have an essential pathogenic role in the neurological/psychiatric symptoms associated with HIV infection, possibly through allowing increased viral expression in the central nervous system.

Immunocytochemical demonstration of human immunodeficiency virus infected cells in the cerebrospinal fluid

Although involvement of the central nervous system represents one of the most common manifestations of the acquired immunodeficiency syndrome (AIDS), a standard diagnostic test for this condition has not yet been established. At necropsy human immunodeficiency virus (HIV) has been demonstrated in brain macrophages in such patients. HIV antigen was detected in CSF macrophages by immunocytochemistry in six out of 11 HIV infected patients. In addition to the detection of intrathecal synthesis of anti-HIV antibodies this method may be suitable for early diagnosis of CNS involvement in AIDS patients.

Human immunodeficiency virus-associated myopathy: analysis of 11 patients

Neuromuscular disorders reported in association with human immunodeficiency virus (HIV) infection include several forms of peripheral neuropathy and polymyositis. We report 11 patients with HIV-associated myopathy. Five patients with acquired immunodeficiency syndrome (AIDS), 2 with AIDS-related complex, and 4 otherwise asymptomatic HIV-infected patients developed progressive proximal muscle weakness. Serum creatine phosphokinase levels were elevated and electromyography revealed abnormal spontaneous activity and myopathy in most patients. All 8 muscle biopsy specimens showed fiber necrosis. Four had inflammatory infiltrates, and nemaline rod bodies were prominent in 3. Immunosuppressant therapy in 5 patients resulted in improvement. Attempts at viral localization in 4 muscle biopsy specimens were unsuccessful. These findings suggest a distinct association between HIV infection and myopathy with features atypical for polymyositis.

Two cases of hypomania in AIDS

HIV disease often leads to neuropsychiatric disturbance, either through direct infection of the brain by the virus or through CNS disease secondary to immunodeficiency. Neuropsychiatric complications of AIDS and AIDS-related disorders may present clinically as acute or chronic organic mental syndromes, or may mimic functional psychiatric illness, in particular depression, anxiety, or psychotic states. Two cases of hypomanic states in homosexual men suffering from AIDS are reported. Neither of the two men had a personal or family history of affective disorder. In one man, hypomanic symptoms were caused by early HIV encephalopathy; he rapidly developed typical HIV dementia with a marked downhill course. In the second case, a clear connection between the hypomanic symptoms and direct HIV brain involvement was not established.

Functional and structural alterations of the nervous system induced by avian retrovirus RAV-7

Chickens infected as embryos with RAV-7 developed neurological signs including ataxia, lethargy, and imbalance. Evoked spinal cord potentials for RAV-7 infected SC chickens were considerably slower (64.8 m/s) than for uninfected SC (103.4 m/s), genetically hypothyroid (OS) (93.9 m/s) or special C (95.1 m/s) chickens. Conduction velocity measurements of sciatic nerves showed normal values for all the chickens examined in this study. Histopathological studies revealed non-suppurative meningoencephalomyelitis in RAV-7 infected SC chickens. The inflammatory infiltrate consisted of lymphocytes, macrophages, and occasional plasma cells. The cells in the infiltrate reacted with mouse monoclonal antibodies directed against la and T-cell antigens. Astrocytic hypertrophy and hyperplasia, demonstrated by the use of monoclonal antibody specific for glial fibrillary acidic protein (GFAP), was associated with the CNS lesions. The results of this investigation indicate that RAV-7 causes significant central nervous system lesions and functional impairment in the infected chicken. This system may serve as a useful model for studying retrovirus-induced neurological dysfunction.

[Amphotericin B in the treatment of neurocryptococcosis in patients subjected to renal transplantation]

Thirty-five cases of cryptococcosis of the central nervous system (CNS) were studied, 17 of them submitted to renal transplantation. The objective was to evaluate the therapeutic responses observed in the group of kidney transplant patients with CNS cryptococcosis. They were submitted to amphotericin B therapy, with emphasis to the renal function. The results in this group were compared with the outcome in the group of patients with the same infection, submitted to the same therapeutic scheme, but without previous impairment of renal function. Among the 35 patients, 20 were male; the age varied between 4 and 76 years. Associated clinical conditions were noticed in 25 patients, 17 of them with renal transplantation. Among 35 patients, 10 died in the first days of the treatment; 25 patients were effectively treated for CNS cryptococcosis, 18 of them with associated clinical conditions; 15 were kidney transplant patients. The drugs used in the treatment of CNS cryptococcosis were, as possible, the amphotericin B by intravenous and intrathecal route (lumbar puncture) associated with 5-fluorocytosine. Seven patients died during the treatment; then, of the 35 patients who were initially evaluated, 17 died and 18 were successfully treated, with a death rate of 48.57%. Various intercurrencies were observed with the use of amphotericin B and 5-fluorocytosine. The clinical and therapeutic results recorded in this study were compared with the information met in literature. The analysis of the results emphasizes the need of the discovery of better and less toxic drugs than those currently used. Amphotericin B still is the most important drug in the treatment of CNS cryptococcosis and the therapeutic scheme currently recommended consists in the association of amphotericin B and 5-fluorocytosine, and there has been also advantage in the simultaneous use of intravenous and intrathecal amphotericin B. Statistical analysis of the results showed that there is no harm with the use of intravenous amphotericin B in renal transplanted patients with cryptococcosis of the central nervous system.

Central nervous system involvement in HIV infection

Central nervous system (CNS) involvement occurs frequently in patients with the acquired immunodeficiency syndrome (AIDS), but at present only a few reports have addressed the analysis of intrathecal IgG synthesis in human immunodeficiency virus (HIV)-seropositive patients with no signs of HIV-related neurologic syndromes. In this study, intrathecal IgG synthesis was investigated using several techniques in patients with different stages of HIV infection and then correlated with the state of the blood-brain barrier. Almost all patients had specific anti-HIV IgG synthesis within the CNS, suggesting the presence of HIV in the brain. These findings further stress that direct CNS infection occurs early in the course of systemic virus spread.

Immunohistochemical and electron microscopic techniques in the diagnosis of viral encephalitides

Electron microscopy and in particular, immunohistochemical examination techniques have substantially improved the chances to attain an etiologic diagnosis in viral encephalitis. The application of these techniques is needed first of all in the examination of cerebral biopsy specimens, but they can contribute to the clearing of the etiology at post mortem study of the brain, too. This review outlines the basic techniques and their application fields. In immunohistochemistry beside the demonstration of specific viral antigens the analysis of the humoral and cellular immune reactions and the identification of the cell types involved by cell specific markers is also important. The second part of the review gives a synopsis of the results of electron microscopic and immunohistochemical studies in the most important acute, subacute and chronic encephalitides occurring in Europe.

AIDS-related lymphoid neoplasia. The Memorial Hospital experience

The clinical features and laboratory results of 63 patients with or at risk for AIDS with lymphoid neoplasias seen from November 1980 through November 1986 are reviewed. Forty-three had systemic non-Hodgkin's lymphoma (NHL), nine had primary large cell lymphomas of the brain, 11 had Hodgkin's disease (HD), and one had plasmacytoma evolving to myeloma. Those with systemic NHL included 40 (93%) with intermediate or high-grade histologies, 35 (81%) with advanced stage (III, IV), and 28 (65%) with extranodal disease at presentation (predominantly marrow and meninges). Overall survival was short (median, 10.5 months from diagnosis) with the majority of deaths attributable to AIDS-related opportunistic infections (OI). However, 17 patients with diffuse NHL achieved a complete clinical remission, and nine now have been disease-free for more than 1 year (median follow-up, 28 months; range, 12 to 73 months). Early stage and lack of systemic symptoms were features associated with prolonged disease-free survival. Primary brain NHL was a uniformly lethal manifestation of AIDS, being diagnosed at postmortem in seven of nine severely immunosuppressed homosexual men. As with NHL, a propensity towards advanced disease and extranodal involvement was also observed in HD, suggesting that the atypical clinical behavior of HD may be an additional epiphenomenon of AIDS. This experience tends to argue for the use of intensive therapy in at least some patients with AIDS-related systemic NHL since it has resulted in a proportion of long-term disease-free survivors.

Activity of clindamycin with primaquine against Pneumocystis carinii in vitro and in vivo

The combination of primaquine with clindamycin is effective in both in vitro and in vivo models of Pneumocystis infection. Primaquine alone at concentrations from 10 to 300 micrograms/ml reduced the numbers of organisms in cultures to less than 7% of control. Significant inhibition was observed down to 0.1 microgram/ml. Clindamycin at 5 micrograms/ml was ineffective alone. Combinations of clindamycin and primaquine in culture at various concentrations were effective, but there was no evidence of true synergy. In rats with established Pneumocystis pneumonia, clindamycin alone at 5 or 225 mg/kg was ineffective. Primaquine alone at 0.5 or 2 mg/kg did not significantly affect the numbers of organisms remaining. The combination of 0.5 mg of primaquine per kg and 225 mg of clindamycin per kg was effective for therapy, lowering the numbers of organisms in the lungs by about 90%. The combination of 2 mg of primaquine per kg and 225 mg of clindamycin per kg was more effective, lowering the numbers of organisms by almost 98%. In the in vivo prophylaxis model, primaquine at 0.1 or 0.2 mg/kg did not prevent the development of Pneumocystis pneumonia in immune-suppressed rats. Clindamycin at 50 mg/kg had a modest effect alone, but at 5 mg/kg all animals became heavily infected. At 0.5 mg/kg, primaquine alone reduced the severity of infection, but seven of eight rats were still infected. In contrast, the combination of 5 mg of clindamycin per kg and 0.5 mg of primaquine per kg prevented infection in 8 of 10 rats; 2 rats had minimal infection. These studies suggest that the combination of clindamycin and primaquine should be tested in therapy or prophylaxis of Pneumocystis infections in humans.

Primary central nervous system lymphoma

Primary lymphoma of the central nervous system (CNS), including reticulum cell sarcoma, microglioma, and histiocytic lymphoma, represents less than 1% of all primary brain tumors. In the last 10 years, this tumor has tripled in frequency in the nonimmunosuppressed population. By 1991, the tumor will be the most common neurological neoplasm by virtue of the increase in sporadic occurrence and in the acquired immunodeficiency syndrome (AIDS) population. Three percent of AIDS patients will develop this tumor either prior to AIDS diagnosis or during their subsequent course. In addition to acquired immunosuppression, patients with inherited disorders (such as Wiskott-Aldrich syndrome, severe combined immunodeficiency, and X-linked immunodeficiency) and other acquired disorders of the immune system are predisposed to the development of CNS lymphoma. Immunological studies have suggested a role for Epstein-Barr virus in the production of this tumor. Although subtypes exist, non-Hodgkin's lymphoma of the CNS most commonly consists of histiocytic cells or large immunoblastic cells bearing B cell surface markers in close proximity to the lateral and third ventricles. Sixty percent of these deposits are multiple, and subarachnoid invasion is seen in one-quarter of patients. Vitreous involvement of the eye occurring prior to and during the course of CNS lymphoma has been noted in up to 25% of patients. The involvement of multiple areas of the neuraxis, the eye, and multiple intracranial sites often occurs in the absence of obvious systemic lymphoma. Therapeutic trials of brain radiation therapy are associated with median survivals of less than 1 year. Uniform complete responses of intracranial deposits are recorded following chemotherapy with high-dose intravenous methotrexate, CHOP (cyclophosphamide, hydroxydaunomycin/doxorubicin, Oncovin (vincristine), and prednisone), high-dose cytosine arabinoside, and intra-arterial methotrexate with barrier modification.

Multiple sclerosis autoantibodies and antibodies in AIDS may deplete a brain peptide hormone

Computerized Chou-Fasman analysis of the secondary structure of human T-cell leukemia viruses (HTLV-I, HTLV-II) and human immunodeficiency virus (HIV) envelope proteins revealed that only one antigenic epitope (amino acids EAL) is shared by the three viruses. A similar antigenic epitope is also found in human and rat brain hormone vasopressin-neurophysin. If autoantibodies in multiple sclerosis (MS) are made to the epitope EAL, they may cross-react with the envelope proteins of HTVL. It is speculated that in AIDS patients, antibodies to the antigenic epitope EAL of HIV may cross-react with brain vasopressin-neurophysin, leading to a decline in this brain peptide hormone. Thus it is hypothesized that treatment of both MS and AIDS patients with a synthetic polymer containing the amino acids EAL might eliminate the antibodies to vasopressin-neurophysin and thus alleviate some of the clinical symptoms.

A diagnosis of AIDS: understanding the psychosocial impact

Acquired immunodeficiency syndrome (AIDS) was discovered in 1981. It is now estimated that 1.5 million persons have become infected and that, by the year 1991, there will be 270,000 cases of the disease and 179,000 associated deaths. An extraordinary aspect of the AIDS epidemic is the high level of fear manifested by large numbers of people, in a manner disproportionate to the objective threat. AIDS has been referred to in the press as the greatest public health problem in America today. While dental journals are replete with studies enumerating the oral manifestations, and appropriate infection control guidelines, the psychosocial aspects of AIDS have generally been confined to media reports. Appropriate dental management of patients at high risk for the development of AIDS/AIDS-related complex requires a complete understanding of the psychosocial environment confronting these persons.

Acute fulminating fatal leukoencephalopathy as the only manifestation of human immunodeficiency virus infection

A case of acute human immunodeficiency virus (HIV) infection manifested by a rapidly fulminating, necrotizing, demyelinating encephalopathy that led to brain death in 5 days is reported. Autopsy demonstrated predominant white matter lesions, acute neuronal damage, and scanty cellular response. Cultures of cerebrospinal fluid were positive for HIV, suggesting an acute infection.

Peripheral neuropathy in the acquired immunodeficiency syndrome

The histopathological and immunopathological features of peripheral neuropathy were investigated in 21 patients with the acquired immunopathological syndrome (AIDS) or AIDS-related complex (ARC). Clinical syndromes observed in the 11 (52%) symptomatic patients included distal symmetrical polyneuropathy (DSPN) and chronic inflammatory demyelinative polyneuropathy (CIDP). Specimens from 19 of 20 patients (95%), both symptomatic and asymptomatic, had histopathological evidence of moderate or severe demyelination (79%), axonal degeneration (36%), and mononuclear cell inflammation (37%). Nerves from patients with CIDP and DSPN showed similar degrees of demyelination and axonal degeneration, but inflammation was more intense in CIDP. Immunohistochemical staining identified the majority of inflammatory cells as T lymphocytes or macrophages, with a predominance of CD8+ cytotoxic/suppressor cells. Diffuse immunostaining for human leukocyte antigen (HLA)-DR was present on endothelial cells, mononuclear inflammatory cells, and Schwann cells, and variable patchy immunostaining for HLA-DR was present on nerve fibers. Control nerve specimens showed staining for HLA-DR limited to endothelial, and a few mononuclear cells. The patterns of immunostaining were similar for AIDS and ARC patients. Human immunodeficiency virus (HIV) was cultured from peripheral nerve in 3 patients, but HIV antigen was not detected by immunohistochemical staining of 8 specimens. The findings implicate HIV infection in nerve, with T cell- and macrophage-mediated tissue destruction as the pathogenetic mechanism of the AIDS/ARC neuropathy.

IgG subclass reactivity against human immunodeficiency virus (HIV) and cytomegalovirus in cerebrospinal fluid and serum from HIV-infected patients

Cerebrospinal fluid (CSF) and serum samples from 17 patients seropositive for the human immunodeficiency virus (HIV) were analysed for specific IgG1-4 against HIV and cytomegalovirus (CMV). Measles IgG was studied as a reference to detect blood-brain barrier (BBB) defects. All patients had IgG1 antibodies against HIV in both CSF and serum, and all had CMV IgG1 in serum (16 in CSF). Anti-HIV IgG was synthesised intrathecally in 11 patients, IgG3 in three patients, and IgG4 in three patients. Intrathecal production of anti-CMV IgG1 was found in three patients, IgG2 in one, IgG3 in three, and IgG4 in one. Intrathecal anti-HIV IgG synthesis could be demonstrated in all stages of the disease. Analysis of all IgG subclasses allowed intrathecal HIV and/or IgG production to be detected also in patients in whom intrathecally synthesised IgG was restricted to IgG2, 3, or 4. The expression of HIV-specific IgG subclasses in CSF and serum was more restricted in AIDS patients than in HIV-infected persons without clinical AIDS. On the contrary, the largest number of CMV-specific IgG subclasses was found in AIDS patients. Intrathecal HIV or CMV IgG subclass production was seen both with and without neurological symptoms. The peripheral T4 cell counts were not obviously related to neurological symptoms. Even patients with low peripheral T4 cell counts had evidence of intrathecal antibody synthesis against HIV and sometimes CMV, suggesting a retained helper function of T cells in the central nervous system.

The peripheral neuropathy of necrotizing arteritis: a clinicopathological study

We have reviewed the clinical and morphological data from 100 patients with necrotizing arteritis in muscle and/or in nerve samples taken by biopsy. The neuropathy occurred in the context of a multisystem disorder (Group 1) or in apparent isolation (Group 2). The average age of patients was 59 in Group 1 and 61 in Group 2. Females were more commonly affected than males, especially in the first group. Necrotizing arteritis complicated the course of rheumatoid arthritis in 25 patients. In 3 patients necrotizing arteritis was associated with infection with the human immunodeficiency virus, the agent of AIDS. Tests for hepatitis B surface antigen were positive in 19 patients. Mononeuritis was present in 13, mononeuritis multiplex in 62, and distal symmetrical sensory or sensorimotor neuropathy in 19 patients. In both groups of patients, the muscle biopsy was more frequently diagnostic for arteritis than was the nerve biopsy (80% versus 55%). The average incidence of isolated fibers undergoing axonal degeneration was 64.8%; that of demyelinated/remyelinated fibers was 1.9%. We conclude that the combination of nerve and muscle sampling increases the chance of visualizing characteristic arterial lesions in vasculitic neuropathy.

Cerebral toxoplasmosis in AIDS. Case report

In a patient with AIDS presenting partial epilepsy cerebral toxoplasmosis was diagnosed on the serological and CT evidence. The diagnosis was confirmed by the immediate response to sulfonamide therapy.

Toxoplasmosis and the acquired immune deficiency syndrome

The literature on toxoplasmosis in the acquired immune deficiency syndrome is reviewed with reference to more than 140 cases from various centres. The incidence, pathogenesis, clinical features, diagnosis, treatment and prognosis are considered.

Neurological complications of human immunodeficiency virus infection

The protean neurological manifestations of human immunodeficiency virus (HIV) infection are reviewed. Both the central nervous system and peripheral nervous system may be affected and many of the complications may occur in individuals with acquired immunodeficiency syndrome (AIDS)-related complex, or who are seropositive for HIV alone as well as those with the established AIDS syndrome. Specific therapy is available for certain of these neurological conditions, but the clinical course in others is untreatable and progressive. Although it seems likely that the pathogenesis of some of these syndromes such as the AIDS-dementia complex are due to the direct effect of HIV on the nervous system, in others the neurological injury probably occurs as a consequence of the immunosuppression which HIV induces, or immune-mediated mechanisms.

Clinical and electrophysiological studies of human immunodeficiency virus-seropositive men without AIDS

Motor weakness and ataxia of lower limbs and abnormalities of somatosensory evoked potentials occur in many patients with the acquired immunodeficiency syndrome (AIDS). We studied 15 human immunodeficiency virus-seropositive subjects without AIDS and found no clinical neurological abnormalities. The mean latency of the brainstem auditory evoked potential (peak V) was increased, suggesting a central defect. Despite normal peripheral nerve conduction along the tibial nerve, the mean latency of the spinal cord potential of the twelfth thoracic vertebra was increased compared with normal, possibly indicating an incipient conduction defect at or near the spinal root ganglion or lumbar spinal cord.

Human immunodeficiency virus and papovavirus infections in acquired immunodeficiency syndrome: an ultrastructural study of three cases

A wide variety of neurologic conditions associated with the acquired immunodeficiency syndrome (AIDS) have been attributed to human immunodeficiency virus (HIV) infection of the central nervous system (CNS). Tissue samples from the brains of three patients with AIDS, diagnosed as having CNS toxoplasmosis on the basis of computed tomographic scans of the head, were studied by transmission electron microscopy. In two, HIV particles were observed budding from, in close association with, and in cytoplasmic vacuoles of mononuclear and multinucleated macrophages, but no other cell types. The patient with the greatest number of HIV particles also had large amounts of papovavirus (progressive multifocal leukoencephalopathy) in the nuclei of oligodendroglial cells and in the cytoplasm of astrocytes. These astrocytes often had atypical features at the light microscopic level. Following an initial biopsy that showed only HIV, primary CNS lymphoma was diagnosed by needle biopsy and confirmed at autopsy in a second case. A diagnosis of progressive multifocal leukoencephalopathy was rendered by transmission electron microscopy in a third case, but no HIV was detected. Toxoplasmosis was not confirmed in any of the three cases. Diagnosis of CNS lesions in patients with AIDS should not rely exclusively on radiography but include biopsy for both light and transmission electron microscopy. Transmission electron microscopy can be employed to reveal HIV and papovavirus infections not discernible at the light microscopic level and should be used as a diagnostic tool in HIV-related infections.

Studies on human immunodeficiency virus-induced cytopathic effects: use of human rhabdomyosarcoma (RD) cells

A full-length molecular clone of human immunodeficiency virus (HIV) proviral DNA was transferred to human rhabdomyosarcoma (RD) cells by gene transfer method. RD cells released infectious virus within 12 hours after transfection and the viral particles present in the culture medium could be quantitated by monitoring reverse transcriptase activity. Chronic low level viral producer cell lines of RD were also established. Southern hybridization analysis revealed the presence of HIV sequences in transfected RD cells. Electron microscopic studies of the transfected cell revealed intracellular budding of HIV and also showed structural abnormalities such as giant cell phenotype and vacuolation. These features qualify RD cells as a useful system for studying the regulation and cytopathic effects of HIV.

The human immunodeficiency virus: infectivity and mechanisms of pathogenesis

Infection with the human immunodeficiency virus (HIV) results in a profound immunosuppression due predominantly to a selective depletion of helper/inducer T lymphocytes that express the receptor for the virus (the CD4 molecule). HIV also has tropism for the brain leading to neuropsychiatric abnormalities. Besides inducing cell death, HIV can interfere with T4 cell function by various mechanisms. The monocyte serves as a reservoir for HIV and is relatively refractory to its cytopathic effects. HIV can exist in a latent or chronic form which can be converted to a productive infection by a variety of inductive signals.

The brain in AIDS: central nervous system HIV-1 infection and AIDS dementia complex

Infection with human immunodeficiency virus type 1 (HIV-1) is frequently complicated in its late stages by the AIDS dementia complex, a neurological syndrome characterized by abnormalities in cognition, motor performance, and behavior. This dementia is due partially or wholly to a direct effect of the virus on the brain rather than to opportunistic infection, but its pathogenesis is not well understood. Productive HIV-1 brain infection is detected only in a subset of patients and is confined largely or exclusively to macrophages, microglia, and derivative multinucleated cells that are formed by virus-induced cell fusion. Absence of cytolytic infection of neurons, oligodentrocytes, and astrocytes has focused attention on the possible role of indirect mechanisms of brain dysfunction related to either virus or cell-coded toxins. Delayed development of the AIDS dementia complex, despite both early exposure of the nervous system to HIV-1 and chronic leptomeningeal infection, indicates that although this virus is "neurotropic," it is relatively nonpathogenic for the brain in the absence of immunosuppression. Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients.

AIDS as a cause of dementia in the elderly

It has been recognized that AIDS can present initially as dementia without other neurological or clinical manifestations. In addition, HIV-contaminated blood transfusions in the elderly seem to be underreported. Because of these findings, dementia in the elderly may be misdiagnosed as Alzheimer's disease or other causes of senile dementia. This paper reports on one patient who presented with a diagnosis of Alzheimer's disease and was later found to have AIDS.

AIDS and the surgeon

Several issues related to the AIDS virus concern the surgeon. This article discusses the common presentations of AIDS in each body system with special emphasis on conditions that require surgical intervention, alternatives to surgical procedures for diagnosis, and precautions for the handling of tissue and body secretions of individuals suspected of harboring the AIDS virus.

Current problems in the management of AIDS patients

Human immunodeficiency virus infection has numerous clinical manifestations and affects patients from a broad spectrum of social, ethical, cultural and psychological backgrounds. As a result the practising physician has to face multiple, recurrent and complicated problems. This review focuses on the means of early diagnosis, treatment and prevention of opportunistic infections. It also stresses the need for a comprehensive multidisciplinary approach to provide optimal care and to diminish the sense of frustration in treating young patients with an ultimately fatal disease.

Chronic HIV encephalitis--II. Clinical aspects

Combined medical, neurological, and serological investigations were carried out in 59 patients infected with human immunodeficiency virus (HIV). In stage I clinical and neuropsychiatric testing did not reveal evidence for HIV encephalitis as diagnosed by local antibody production in CSF. Neuropsychiatric abnormalities, brain atrophy, memory and cognitive impairment reliably indicated HIV encephalitis in later stages. The commonest symptoms were cerebellar and brainstem signs, followed by dementia. Epileptic fits and hemiparesis always were associated with cerebral toxoplasmosis. A polyneuropathy was frequently found but other causes have to be considered.

AIDS and neurological disorders: an overview

Neurological disease occurs frequently in patients infected with the human immunodeficiency virus. Disorders may affect either the central or peripheral nervous systems and may be the presenting manifestation of human immunodeficiency virus-related disease. Opportunistic infections and lymphomas are major causes of central nervous system disease. Increasingly, however, human immunodeficiency virus infection of the central nervous system is being recognized and is now associated with a syndrome of progressive dementia in adults, referred to as the acquired immunodeficiency syndrome dementia complex, and an encephalopathy in infants born to human immunodeficiency virus-infected mothers. Whether brain disease related to this virus will respond to antiretroviral drugs will be a major focus of future research. Although less frequent than central nervous system disease, disorders of the peripheral nervous system are increasingly being recognized, including cases that probably have an autoimmune basis.

The AIDS dementia complex: some current questions

The acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) commonly complicates the course of human immunodeficiency virus (HIV) infection and AIDS. Although many of its clinical aspects have recently been brought into clearer focus, and pathogenetic evidence has accrued implicating direct HIV brain infection, there remain a number of fundamental aspects of ADC and HIV nervous system infection that require clarification. These include clearer definition of the clinical syndrome and its variants; development of instrumentation for diagnosis and monitoring the disorder; definition of the epidemiology and natural history of both central nervous system HIV infection and ADC, which may seemingly be discordant; and understanding of both the viral pathogenesis and the biology of resultant brain dysfunction. Elucidation of these fundamental issues will enhance rational development and evaluation of therapy.

Role of mononuclear phagocytes and accessory cells in human immunodeficiency virus type I infection of the brain

The cells responsible for persistence of viral infection in the brains of human immunodeficiency virus type I-positive individuals are most likely mononuclear phagocytes. The infection of other cell types within the brain is presumably the result of close interactions with HIV-I-producing cells of the mononuclear phagocytic lineage. During these interactions, both direct effects from HIV-I infection of brain cells as well as indirect mechanisms (namely the response of brain cells to the presence of virus-infected cells, particularly monocytes and macrophages) should be considered. In addition, the genomic variability of HIV-I could play a role in increasing the tropism of the virus for certain cell types.

Preliminary molecular characterization of a human immunodeficiency virus (HIV-I) associated with neuropathology

A human immunodeficiency virus (HIV-I) was isolated from the brain of a patient with progressive dementia but no obvious immunosuppression. This isolate, designated as HIV-IBR, was molecularly cloned and sequenced, and its long terminal repeat (LTR) and envelope sequences were compared with those of other HIV isolates not uniquely associated with dementia. The HIV-IBR LTR showed marked homology with the LTR sequences of the other HIV-I isolates. The predicted amino acid sequence of the external glycoprotein (gp120) of HIV-IBR revealed a pattern of conserved and variable regions similar to that of other HIV isolates. The sequence of the transmembrane portion of envelope, gp 41, was highly homologous to the counterpart region of other isolates. Further analysis is required to determine whether specific sequence variation can account for neurological manifestations of HIV-IBR infection.

Peripheral neuropathies associated with human immunodeficiency virus infection

Peripheral neuropathies may complicate all stages of infection with human immunodeficiency virus (HIV). Acute inflammatory demyelinating polyneuropathy, sensory ganglioneuritis, and acute cranial nerve palsy all may occur 2 to 3 weeks after acute HIV infection. Acute inflammatory demyelinating polyneuropathy, chronic inflammatory demyelinating polyneuropathy, and polyradiculopathy may occur with otherwise asymptomatic HIV virus infection. Neuropathy is one of the most common neurological manifestations of the acquired immunodeficiency syndrome (AIDS)-related complex, occurring in as many as 20% of these patients. Acute or chronic inflammatory demyelinating polyneuropathy (38%) and mononeuropathy multiplex (29%) are most frequently seen, and usually there is a good prognosis, with the neuropathy resolving spontaneously or with steroids or plasmapheresis. Neuropathy occurring with AIDS is reportedly uncommon but probably is underreported, especially in seriously ill patients. By contrast with AIDS-related complex, the neuropathy associated with AIDS is usually a distal symmetrical polyneuropathy (72%), with inflammatory neuropathy, mononeuropathy multiplex, and polyradiculopathy occurring rarely. The pathogenesis of acute or chronic inflammatory demyelinating polyneuropathy and possibly of mononeuropathy multiplex is probably autoimmune. The pathogenesis of distal symmetrical polyneuropathy is less clearly established and may be infectious, toxic, or nutritional. Polyradiculopathy most likely is infectious; cytomegalovirus is a leading contender for infectious agent, but herpes simplex virus and HIV are other possibilities.

Psychosocial and neuropsychiatric aspects of HIV infection: review of their extent and implications for psychiatry

HIV infection in general and AIDS in particular, present a major challenge for the health services worldwide. The possibility of central nervous system effects of HIV infection has been known for some time, and information is now accumulating about the range of psychiatric disorders associated with it. This paper considers in detail the psychosocial and neuropsychiatric problems which can develop at the various stages of HIV infection, and discusses the implications for the mental health services in terms of provision of services, legal and ethical problems, and further research.

Protozoal infections in the acquired immunodeficiency syndrome

Several protozoa have emerged as the major opportunistic infections and cause of death in patients with acquired immunodeficiency syndrome (AIDS). Pneumocystis carinii pneumonia is the leading cause of death in AIDS patients. Electron microscopy (EM) usually shows numerous trophozoites and cysts of Pneumocystis filling up the entire alveolar space, while only cysts are seen under the light microscope. The focal thickening of cyst wall of Pneumocystis, as demonstrated by EM and manifested as a "parentheses" shaped structure with silver stain, serves as a diagnostic marker for Pneumocystis. Freeze-fracture EM has demonstrated the intimate contact between Pneumocystis trophozoites and the type I pneumocytes, which may contribute to the alveolar-capillary block, leading to severe respiratory distress. However, EM is seldom needed for the diagnosis of this infection. Toxoplasma encephalitis, which is an unusual clinical manifestation in cases of toxoplasmosis reported previously, has become a common complication and one of the major causes of death in patients with AIDS. Because subclinical infection by Toxoplasma is common, serologic tests usually offer no definite answers as to whether the infection is acute or chronic, active or past. The small size and its non-specificity in both morphology and tissue affinity make light microscopic diagnosis of toxoplasmosis difficult. Only immunologic staining, such as immunoperoxidase and immunofluorescence, can help to achieve a definite positive identification of the organism. When special antibodies or facility for such staining is not available, EM is the final resort for identifying Toxoplasma by showing the apical complex with the characteristic sausage-shaped rhoptries. Cryptosporidiosis, practically unknown before the AIDS outbreak, has become one of the most common intestinal protozoa in both immunocompromised and immunocompetent patients. The protracted and sometimes fatal course of cryptosporidiosis in immunocompromised patients can be explained by the presence of autoinfective oocysts (thin-walled oocysts), as detected by EM, and by recycling of first-generation schizonts observed experimentally. While diagnosis of cryptosporidiosis can be made by detection of oocysts in stools in most cases, EM is still the last resort for a definitive identification of Cryptosporidium species. While the incidence of isosporiasis is still low, it has been found more frequently in patients with AIDS than in the general population. The parasite, Isospora belli, being a coccidian as is the Cryptosporidium species, is similar to the latter in its life cycle and clinical manifestations.(ABSTRACT TRUNCATED AT 400 WORDS)