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J Michaels

Publications and source records attributed to J Michaels.

31 records · Page 2Linked to original sources
PubMed1991

Serial pathogenesis study of SIV brain infection.

A serial study of early SIV brain infection revealed initial involvement of leptomeninges, followed by perivascular infection of brain parenchyma. Severity of SIV encephalitis correlated with severity of systemic disease rather than with length of infection. Diffuse white matter disease was not observed, and there was little evidence of SIV infection of brain endothelial cells. SIV infection of leptomeninges is separate from infection of the brain, which appears to be due to transvascular spread of infected monocytes/macrophages.

Animals↗
PubMed1990

Spinal cord disease in children with HIV-1 infection: a combined molecular biological and neuropathological study.

An autopsy study was performed on spinal cords from 18 children who died with HIV-1 infection, using standard histopathologic techniques as well as in situ hybridization and immunocytochemistry for HIV-1. Of 16 spinal cords examined by histology, nine had inflammatory cell infiltrates and six had multinucleated cells; both types of lesion are associated with the presence of HIV-1 in central nervous system tissue. HIV-1 type lesions were often present in the spinal cord and brain from the same patient. Pallor of myelin in corticospinal tracts in the cord was present in half of the cases; this change correlated with diffuse myelin pallor in the corresponding brains, but not with the HIV-1 associated changes in the cords. In situ hybridization for HIV-1 nucleic acid sequences gave positive results in seven of 18 spinal cords, with hybridizing signal usually localized to inflammatory cell infiltrates and multinucleated cells. Positive in situ hybridization, on frozen sections, correlated with the presence of HIV-1 associated changes on paraffin sections from the same cases. Immunocytochemistry for p25 core protein of HIV-1, using a monoclonal antibody on frozen sections, was positive in multinucleated cells, macrophages, and microglia. In this series there were two cases of vacuolar myelopathy, one a 30-month-old boy who had concomitant measles virus in the spinal cord grey matter, and the other nine-year-old girl who had severe HIV-1 infection of the cord. Other than the single case of measles virus, there were no opportunistic infections in the cords in this series. HIV-1 frequently involves the spinal cord in children with AIDS, while opportunistic infections are rare. Vacuolar myelopathy occurs in children with HIV-1 infection, although its occurrence is much less frequent than in adults with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Weight training decreases vertebral bone density in premenopausal women: a prospective study.

The effect of exercise on bone mass is unclear. To determine the skeletal effect of weight-bearing exercise in premenopausal women, we prospectively evaluated the effects of a weight-training program on lumbar spine bone mass in 10 women (mean +/- SEM, 36.2 +/- 1.3 yr) and compared the results with those in 7 sedentary women (40.4 +/- 1.6 yr). None of the women had previously participated in a weight-training program, and all ingested a 500-mg calcium supplement each day throughout the study. Axial loading and balance of large muscle groups were emphasized. Individual strength increased by 57 +/- 8% over 9 months. Despite the increase in muscle strength, lumbar spine bone density in the exercising women decreased by 2.90% at 4.5 months and 3.96% at 9 months (P = 0.01). In contrast, there was no change in lumbar density in the controls over the 9-month period. We conclude that short term weight training at this frequency and intensity decreases vertebral bone mass in premenopausal women.

Adult↗
PubMed1989

Evaluation of an atypical HIV type 1 antibody. Serologic pattern leading to detection of HIV type 2 infection in North America.

The variability and discordance of human immunodeficiency virus type 1 (HIV-1) antibody enzyme immunoassay determinations on serial specimens derived, to our knowledge, from the first documented case of HIV-2 infection in North America are described. The initial specimen was weakly reactive, but two subsequent serum specimens were both nonreactive by enzyme immunoassay. All specimens were indeterminate for HIV-1 antibody by HIV-1 Western blot analysis. Serum HIV-2 antibody was demonstrated by enzyme immunoassay using whole virus lysate, HIV-2-specific synthetic peptide assays, and HIV-2 Western blot analysis. Human immunodeficiency virus type 2 genomic sequences were demonstrated in peripheral blood mononuclear cells using gene amplification technology. Human immunodeficiency virus type 2, isolated from peripheral blood lymphocytes, had typical morphologic features of lenti-virus by electron microscopy. Western blot analysis and other specific assays should be considered in individuals with clinical evidence suggesting HIV infection who are nonreactive for HIV-1 antibody by enzyme immunoassay or who have atypical reactivity patterns.

Acquired Immunodeficiency Syndrome↗
PubMed1989

HIV-2-associated AIDS in the United States. The first case.

A 41-year-old woman from the Cape Verde Islands, Africa, who had been residing in the United States for 11 months was found to have human immunodeficiency virus type 2 (HIV-2)-associated acquired immunodeficiency syndrome (AIDS). Antibody to HIV-2 was found by enzyme immunoassay and was verified by radioimmunoprecipitation. The patient was being treated for pulmonary tuberculosis at the time of her admission to our institution. Further laboratory and clinical evaluation at our facility revealed depressed CD4 lymphocytes, oral candidiasis, and cryptococcal meningitis with indeterminate results on serologic testing for HIV type 1 (HIV-1). The biopsy specimen of a lesion in the right occipital lobe of the brain documented Toxoplasma gondii, indicating a clinical diagnosis of AIDS. To our knowledge, our study presents the first known patient with HIV-2-associated AIDS in the United States. Our patient provides further evidence that HIV-2 causes severe immunodeficiency and opportunistic infection. The condition should be suspected in the face of normal or repeatedly equivocal HIV-1 antibody test results in the presence of clinically documented AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Microglia in the giant cell encephalitis of acquired immune deficiency syndrome: proliferation, infection and fusion.

The autopsied brains of three homosexual men with acquired immune deficiency syndrome (AIDS), progressive encephalopathy and widespread multinucleated giant cell encephalitis were investigated by lectin and immunohistochemical methods to ascertain the cellular distribution of a human immunodeficiency virus (HIV) core protein, p25. Abundant viral antigen was present in all brains, limited to perivascular macrophages, microglial and multinucleated cells, some bearing elongated cytoplasmic processes. The multinucleated cells were consistently labelled by the lectin Ricinus communis agglutinin-1, a marker for microglia, which demonstrated process-bearing variants of these cells. The prominent staining of microglia for viral antigen and the morphological suggestion that they fuse with other microglia and/or macrophages to form the multinucleated cells characteristic of HIV encephalitis indicate that microglia are probably direct targets of HIV infection and serve to propagate and amplify this retroviral encephalitis.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Human immunodeficiency virus type 1 (HIV-1) infection of the nervous system: a review.

Human immunodeficiency virus type I (HIV-1) is associated with a spectrum of neurological disorders. At the time of primary HIV-1 infection, an acute aseptic meningitis or encephalitis indicates central nervous system invasion. Evidence of HIV-1 infection is found in the CSF of most asymptomatic seropositive individuals, suggesting viral persistence in the nervous system. After a long incubation period, viral activation is signaled by expression of HIV-1 antigen in the CSF, which correlates with a profound dementia in adults or with an analogous progressive encephalopathy in children. The neuropathological substrate of this dementing process consists of multinucleated giant cells and diffuse white matter pallor. Immunocytochemical and in situ hybridization studies demonstrate that antigen presenting cells, including blood derived macrophages and resident brain microglia, are directly infected by HIV-1, and participate in the formation of the syncytial giant cells. Astrocytes and endothelial cells may also be infected, but evidence for infection of oligodendroglia and neurons is lacking. Studies of lentiviral encephalitides in ungulates and non-human primates emphasize the importance of specific viral antigenic stimulation and the role of inflammatory cells as direct or indirect mediators of tissue damage. The disorders of the peripheral nervous system described in patients with HIV-1 infection have not been convincingly linked to direct viral infection. At least two of the neuromuscular complications, the inflammatory motor neuropathy and polymyositis are likely to have an autoimmune pathogenesis.

Acquired Immunodeficiency Syndrome↗
PubMed1980

Magnocellular hypothalamic projections to the lower brain stem and spinal cord of the rat. Immunocytochemical evidence for predominance of the oxytocin-neurophysin system compared to the vasopressin-neurophysin system.

The paraventricular nucleus of the rat hypothalamus has been shown to project to the medulla and spinal cord. The proportion of oxytocin-neurophysin (OTNP) axons to vasopressin-neurophysin (VPNP) axons in these structures is unknown. A major difficulty in resolving this problem in previous immunocytochemical studies was the lack of a specific antiserum to each rat neurophysin. In this study two approaches have been used: (1) comparison of immunostaining for neurophysin in normal versus homozygous Brattleboro rats with diabetes insipidus (HODI) which lack VPNP, and (2) application of an antiserum to both rat neurophysins absorbed with HODI rat hypothalamic-pituitary extracts which contain only OTNP. The latter would result in an antiserum specific for VPNP. Our results indicate that the axons which constitute the caudal projections from the paraventricular nucleus are predominately oxytocinergic, the vasopressinergic innervation being limited to the nucleus tractus solitarius, the dorsal motor nucleus of vagus, and the substantia gelatinosa. A similar number of reactive fibers were seen in the medulla and spinal cord of normal and HODI rats. No positive perikarya were observed caudal to the hypothalamus. Fibers in the medulla appeared to terminate in the nucleus of the solitary tract and in the dorsal motor nucleus of the vagus nerve. Positive fibers throughout the cord were present in the substantia gelatinosa and in the intermediolateral grey. The possible role(s) of these projections in integrating autonomic functions and afferent information with neuroendocrine regulation is discussed.

Animals↗