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

Non-Immunoglobulin Salivary Agglutinins (NIA) which directly bind to microbes [including HIV] were studied for their potential to activate the first complement component (C1). It was determined that NIA had the same specific activity as heat aggregated IgG in binding to C1q and in activating C1. In order to determine the region of C1q which bound to NIA, C1q globular heads and C1q stems (collagen-like regions) were prepared and separated via a Western blot procedure. NIA bound principally to the globular heads of C1q and weakly to the collagen-like stem region. NIA were also studied for their potential to activate native C1 in normal human serum. Heat-aggregated IgG and cardiolipin served as positive controls. It was observed that incubation of isolated NIA with fresh normal human serum resulted in the formation of sodium dodecyl sulfate (SDS)-irreversible complexes of activated C1r-C1 inhibitor and activated C1s-C1 inhibitor and in activated C1s mediated C4 conversion. This indicated that isolated NIA had the potential to directly and effectively mediate classical complement pathway activation. Preincubation of NIA with C1q, blocked NIA mediated C1r and C1s activation and C4 conversion. The concn of NIA required to activate C1r and C1s was similar to that of heat-aggregated human IgG. In kinetic ELISA, NIA or aggregated IgG (positive controls) were first immobilized on microtiter plates, blocked with gelatin then incubated with fresh human serum as a source of complement. Depositions of C4b, C3b and iC3b substantiated that the complement system was effectively activated by immobilized NIA. The optimal relative NaCl concn for C4b deposition was 0.11 M. While pre-incubation of NIA with C1q blocked the subsequent C1 fixing potential of NIA, pre-incubation of NIA with rgp160 [HIV-1] or fibronectin did not interfere with the potential of NIA to fix C1.
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PMID:High molecular weight non-immunoglobulin salivary agglutinins (NIA) bind C1Q globular heads and have the potential to activate the first complement component. 843 9

Several neuropathologic findings in infants and children with human immunodeficiency virus type-1 (HIV-1) infection are different from those observed in adults, probably related to the fact that the retroviral infection occurs in the setting of neuro-development. This report describes the interaction and biologic activity of tat, the HIV-1 trans-activating protein on human neuroblasts. Two human neuroblastoma cell lines, LAN-5 and GI-CA-N, have been studied for their capability to adhere to tat (full recombinant protein) and to two different peptide residues of it. Both cells adhere to tat and tat46-60 basic domain, although not to tat65-80 residue, which contains the RGD (arginine-glycine-aspartic acid) motif. Adhesion to collagen I was inhibited by preincubating GI-CA-N cells with tat,46-60 although not with tat,65-80 indicating the capability of the basic residue to interfere with collagen I-induced cellular adhesion. The expression of 200-kD neurofilaments induced by collagen I was not induced by tat,46-60 indicating that neural differentiation along the same pathway is not mimicked by this peptide. Neuroblast cell proliferation was not affected by adhesion to tat46-60 nor to tat.65-80 GI-CA-N cells are not permissive to HIV-1 infection. However, proviral DNA was documented in the cell lysate for 14 consecutive in vitro passages, whereas HIV-1 transcription was never detectable. This would exclude the possibility that tat would be transduced by these cells. GI-CA-N stained negative for CD4, although positive for Gal-C, which may explain HIV-1 entry. Results show that immature human neural cells interact with tat protein and/or its basic residue in vitro. A mechanism similar to that herein described would possibly be active in vivo, which may help in clarifying the pathogenic mechanisms of neurologic dysfunction and destruction of the CNS observed in infants infected with HIV-1.
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PMID:Adhesion of human neuroblasts to HIV-1 tat. 855 50

Given the similarities between the two viruses, the feline immunodeficiency virus (FIV) is becoming an interesting animal model for human immunodeficiency virus (HIV) studies. To explore the still controversial role of the liver in the development of HIV infection, sinusoidal endothelial cells (SEC) were isolated, and primary cultures were infected with the FIV Villefranche IFFA strain. The isolated cells were characterized by their typical fenestrations, the presence of von Willebrand factor (vWf), and their ability to take up acetylated low-density lipoproteins and denatured collagen. Two weeks after infection, significant amounts of FIV p24 antigen were detected by immunofluorescence in both multinucleated giant and single cells and by enzyme-linked immunosorbent assay in the culture medium. High amounts of viral particles were observed together with different steps of budding at the plasma membrane or at the membrane of intracytoplasmic vacuoles. The released viral particles were shown to be infectious for a permissive cell line. During the first 3 weeks of infection, the only cytopathic effect of FIV was syncytia formation. No noticeable impairment of the pattern of fenestrations and the modulation of their number by a cytoskeleton-mediated process occurred. The productive infection of SEC may contribute to the progression of the infection.
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PMID:Productive infection of primary cultures of endothelial cells from the cat liver sinusoid with the feline immunodeficiency virus. 862 Nov 76

In contradistinction to older populations, immune-mediated disorders (principally demyelinating processes) account for nearly half of peripheral neuropathies in childhood. The largest single diagnostic entity is GBS, which makes up approximately 25% of sensorimotor neuropathies in patients under 18 years of age. The clinical features are similar to those encountered in adults, although the prognosis in youngsters appears to be better than in older populations. Despite the absence of prospective data, plasmapheresis seems to be an effective modality for hastening recovery during GBS in children. The use of human immunoglobulin has gained acceptance for the treatment of GBS in adults, but insufficient data exist to draw firm conclusions about it role in the management of paediatric GBS. CIDP is the second most common cause of chronic sensorimotor neuropathy in children. The clinical manifestations of this disorder are extremely variable, and it can mimic the phenotype of several genetically determined neuropathies. The prognosis in this disorder is also relatively good, although a small number of children have significant neurological disability or treatment side-effects. Other immune-mediated neuropathies are relatively infrequent in our experience. When they occur, they are often associated with collagen-vascular diseases or bone marrow transplantation. Peripheral neuropathy in association with HIV infection in children appears to be rare.
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PMID:Immune neuropathies in childhood. 873 10

An autoreactive cellular immune response may be a part of HIV-1 infection. This autoimmune phenomenon also includes antibodies to collagen that can be associated to arthritis as a clinical condition. In this paper we describe a case of Still's disease in an adult HIV-1 infected patient who presented a marked amelioration in his condition after 15 days of steroid therapy, as well as an improvement of the arthritis. This rare autoimmune condition, which is connected with the disregulation of the immune system, must be taken into account in HIV-1 infected individuals who present with fever of unknown origin.
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PMID:Still's disease in a patient infected with human immunodeficiency virus type I. 883 52

Spindle cells and vascular endothelium in nodular lesions of AIDS associated (epidemic) and endemic Kaposi's sarcoma showed similar immunohistochemical patterns of expression for cell adhesion molecules and extracellular matrix proteins. Spindle cells as well as endothelium also expressed both alpha 5 and alpha V integrin subunits and ICAM-1 suggesting a possible role for inflammatory cytokines in spindle cell formation. The spindle cell compartment was rich in collagen, laminin, fibronectin and tenascin suggesting an important reactive component in the evolution of Kaposi's sarcoma. The lack of thrombospondin expression in the spindle cells favours the contention that they could be transitional, proliferating cells of endothelial origin. Specific expression of tat protein was not seen suggesting minimal if any HIV replication in these lesions. Our findings suggest similar histopathogenetic mechanisms for endemic and epidemic Kaposi's sarcoma. The clinically more malignant features of most AIDS related cases may reflect an important effect of systemic and focal cytokines in HIV patients and possibly other cofactor(s), i.e. tat protein in the induction and growth of the lesions.
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PMID:Expression of adhesion molecules in endemic and epidemic Kaposi's sarcoma. 891 41

Bronchoalveolar lavage (BAL) samples used to study immune or inflammatory response in interstitial lung disease must be representative of the lower respiratory tract. Thus, the selection of suitable samples must be part of routine practice. To assess the incidence of unsuitable BAL samples used for cytology and to determine the relation between parameters related to underlying disease and the quality of samples. One hundred sixty-one patients were enrolled. Seventy-two were HIV positive and had diffuse pulmonary infiltrates, 34 had idiopathic pulmonary fibrosis (IPF), 10 had sarcoidosis, 10 had hypersensitivity pneumonitis, 19 had interstitial lung disease and collagen diseases and 2 had pulmonary eosinophilia. Fourteen individuals formed the control group. The quality study was carried out by staining the BAL samples following a modified Wright-Giemsa technique and evaluating the samples by the selection criteria described by Chamberlain and colleagues (1987). We identified unsuitable samples from 53% of the HIV positive patients, from 35% of the IPF patients and from 21% of the interstitial lung disease patients with associated connective tissue disease. In the other groups, all samples were suitable for analysis. Intolerance of BAL with decreasing percentage of fluid recovered was significantly associated with sample quality, particularly in the IPF group. The cytology results that invalidated the samples differed by group. In all groups, unsuitable specimens had low cell counts. The finding or not of evidence of associated infection in HIV-infected patients, on the other hand, did not appear to determine sample quality in and of itself, although it did in samples related to other entities. We can predict that a high rate of unsuitable BAL samples will come mainly from patients with diffuse lung disease associated to HIV infection, IPF and interstitial lung disease with associated connective tissue disease. Tolerance to the technique influences quality of the specimen obtained and, therefore, should be taken into account in interpreting the findings of cytology. The criteria applied by the various teams using BAL should be unified, and it should be determined whether the exclusion of inappropriate samples affects the final composition of study groups.
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PMID:[Quality and selection of samples of bronchoalveolar lavage (BAL) in diffuse pneumopathies]. 896 12

Haemophilus ducreyi is the causative agent of the genital ulcer disease Chancroid. Chancroid has been shown to increase the risk of heterosexual transmission of HIV. Little is known regarding the attachment or localization of this organism to human cells in either the dermal or epidermal layer. In this study the attachment of H. ducreyi to human foreskin fibroblast (HFF) cells was further characterized. Attachment was mediated by more than one mechanism. Proteinase K treatment but not trypsinization of H. ducreyi significantly reduced attachment suggesting protein involvement. In addition, purified lipooligosaccharide (LOS) was able to inhibit attachment in a dose dependent manner. It appeared that the organism binds to fibronectin in the extracellular matrix of HFF cells, since competition studies using fibronectin showed that it was able to significantly reduce attachment in a dose dependent manner whereas collagen did not. We hypothesize that the attachment of H. ducreyi involves both a protein mediator of attachment (likely pili) as well as LOS and that one or both of these bacterial components interacts with fibronectin in the extracellular matrix to mediate attachment to HFF cells.
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PMID:Attachment of Haemophilus ducreyi to human foreskin fibroblasts involves LOS and fibronectin. 903 61

Cervical lymph nodes biopsies from 31 HIV positive patients (with or without AIDS) were studied by histologic methods and immunohistochemistry (StreptABC staining of paraffin sections) to identify cellular and extracellular matrix components. The results were the following: (1) the biopsies were included in the stages of follicular hyperplasia without fragmentation FH-FF (4 cases); follicular hyperplasia with follicular fragmentation FH + FF (16 cases); follicular involution FI (6 cases) and diffuse pattern DP (5 cases); (2) the most important alteration was the germinal centers disruption due to follicle lysis, which began in the light zone; (3) there was coincidence between intrafollicular hemorrhages and segmental hyaline mycroangiopathy; (4) during the progression of the disease occurred; (a) an increase in the number of mast cells, CD68+ and Mac 387+ macrophages; (b) a diffuse augment of collagen III, elastic fibers, laminin, fibronectin and proteoglycans; (c) maintenance of Factor VIII-related antigens in the vascular endothelial cells, with decrease in the expression of Ulex-Europeus I lectin. Follicular hyperplasia (FH - FF or FH + FF) was the most common histologic pattern recognized in the lymph nodes of patients without AIDS and follicular involution and difuse pattern were seen in those who had AIDS. The results indicate that the lymph node biopsies may provide important information about the evolutive stage of the disease and its prognosis.
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PMID:Spectrum of morphologic changes of lymph nodes in HIV infection. 904 Aug 59

Glucocorticoid (GC) use is known to induce or enhance the growth of Kaposi's sarcoma (KS) in many clinical settings including human immunodeficiency virus infection, collagen vascular disease, lymphoproliferative disorders, and renal transplantation. Because GCs may induce immune suppression and thus tumor growth, we determined whether GCs had a direct effect on KS growth. We found that GCs directly induce the growth of KS cell lines. In examining the mechanism of action of GCs, we did not observe induction of known autocrine growth factors for KS including interleukin-1 (IL-1), IL-6, oncostatin-M, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF). We thus examined factor(s) that inhibit KS growth. Transforming growth factor-beta (TGF-beta) is produced by KS cells and has pleiotropic effects, including inhibiting the growth of hematopoietic and endothelial cells. We show that TGF-beta is produced by KS cells in both the latent and active forms, and that TGF-beta is an autocrine growth inhibitory factor. We then studied the effects of GCs on the regulation of TGF-beta and found that GCs do not inhibit TGF-beta transcription, but significantly inhibit TGF-beta activation. This effect is mediated through regulation of the TGF-beta activation pathway. TGF-beta is activated by plasmin which is positively regulated by plasminogen activator (PA) and PA receptor (PAR), and negatively regulated by plasminogen activator inhibitor (PAI). GCs downregulated PAR and upregulated PAI. Thus, glucocorticoids enhance KS cell growth through the regulation of TGF-beta activation.
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PMID:Glucocorticoids induce Kaposi's sarcoma cell proliferation through the regulation of transforming growth factor-beta. 905 28


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