Demonstration of Epstein-Barr virus in scrape material of lateral border of tongue in heart transplant patients by negative staining electron microscopy.

Scrape material from the lateral border of the tongue of 50 heart transplant patients and 20 controls was studied for the presence of EBV by negative staining electron microscopy. Mild oral hairy leukoplakia was observed in two cases. Particles of the herpes virus were found in 20% of the specimens.

Immunoelectron microscopic localization of collagens type I, V, VI and of procollagen type III in human periodontal ligament and cementum.

We examined the ultrastructural localization of collagens Type I, V, VI and of procollagen Type III in decalcified and prefixed specimens of the periodontal ligament and cementum, by immunoelectron microscopy using ultra-thin cryostat sections. Immunostaining for collagen Type I was pronounced on the major cross-striated fibrils entering cementum and in cementum proper, whereas staining for procollagen Type III was almost exclusively observed on the major fibrils in the periodontal ligament situated more remote from cementum. Reactivity for collagen Type V was limited to aggregated, unbanded filamentous material of about 12 nm diameter that was found mainly in larger spaces between bundles of cross-striated collagen fibrils and occasionally on single microfibrils that apparently originated from the ends of the major collagen fibrils, which may support the concept of this collagen as a component of core fibrils.

Analysis of non-infectious HIV particles produced in presence of HIV proteinase inhibitor.

Newly developed substrate analogue peptidomimetics are able to inhibit the human immunodeficiency virus, HIV-1 proteinase at nanomolar concentration. In HIV infected cell culture they exhibit antiviral activity. We have analyzed the non-infectious HIV particles produced in chronically HIV infected cell culture in presence of one of these inhibitors.

Immunoelectron microscopy shows an atypical pattern and a quantitative shift of collagens type I, III and VI in oral Kaposi's sarcoma of AIDS.

The localization of collagen types I, III and VI in normal human alveolar and palatal mucosa and in oral Kaposi's sarcoma (KS) was studied by light microscopy and cryo-immunoelectron microscopy. Normal oral mucosa revealed two different types of organization. The upper connective tissue stroma contained a loose reticular network mainly composed of collagen types III and VI, while collagen type I immunostaining predominated in the deeper stroma.

Inhibition of the retroviral HIV-proteinase impairs maturation to infectious human immunodeficiency virus (HIV).

Newly developed inhibitors block the aspartic-type retroviral proteinase of the human immunodeficiency virus (HIV) at nanomolar concentration. The viral proteinase is responsible for the processing of viral encoded proteins. Applied to HIV infected cell culture, these inhibitors exhibit antiviral effects.

Biological and physicochemical characterization of the major (1.40) and minor (1.45) component of infectious avian adeno-associated virus.

Two infectious components with buoyant densities of 1.40 g/cm3 and 1.45 g/cm3, designated as major (1.

Clonal diversity and virulence factors in strains of Escherichia coli of the classic enteropathogenic serogroup O114.

Eighty-eight Escherichia coli strains of the enteropathogenic (EPEC) group O114 that were isolated from humans and animals in geographically different places and over more than 30 years were examined for virulence markers, O:H serotypes, and for electrophoretic types by multilocus enzyme electrophoresis. Four major genetically tightly related clusters of strains showed close correlation between electrophoretic types and other phenotypic characters. Cluster I contained 35 EPEC class II strains of serotypes O114:H9 and O114:H- and 5 enterotoxigenic E.

[Intestinal spirochetosis in HIV infection: prevalence, isolation and morphology of spirochetes].

The prevalence of intestinal spirochaetosis was investigated in 39 HIV-positive homosexual males (mean age 39 [24-65] years) in different stages of HIV infection (3 with the lymphadenopathy syndrome, 8 with AIDS-related complex and 28 with AIDS). Biopsies for cultural and histological demonstration of spirochaetes were obtained during routine ileoscopies. At the time of examination 35 of the 39 patients had intestinal symptoms.

Negative staining EM for the detection of Epstein-Barr virus in oral hairy leukoplakia.

The performance of two different EM techniques applied for the detection of Epstein-Barr Virus (EBV) in oral hairy leukoplakia (HL) was assessed, i.e. the conventional two-step method of negative staining (CNS) and negative staining after Airfuge enrichment (ANS).

Infection of the human monocytic cell line Mono Mac6 with human immunodeficiency virus types 1 and 2 results in long-term production of virus variants with increased cytopathogenicity for CD4+ T cells.

The recently established human monocytic cell line Mono Mac6 expressing distinct characteristics of mature monocytes/macrophages was tested for its susceptibility to infection with human immunodeficiency virus. Inoculation of the cells with the T-cell-tropic human immunodeficiency virus strains human T-lymphotropic virus type IIIB and lymphadenopathy-associated virus type 2 led to a noncytopathic productive infection becoming apparent only after a latency period of up to 56 days. The infectibility of the Mono Mac6 cells was dependent on low levels of CD4 expression, as demonstrated by blocking experiments with various CD4-specific antibodies.

Molluscum contagiosum associated with AIDS: a case report with ultrastructural study.

The clinical features of perioral molluscum contagiosum in a patient with the acquired immunodeficiency syndrome are described. Light microscopy and thin section electron microscopy revealed epidermal cells in different stages of degeneration showing two types of cytoplasmic inclusions. The basement membrane exhibited discontinuities and multiple laminations which may be a response to viral-induced cytotoxic effects.

Oral hairy leukoplakia in an HIV-seronegative heart transplant patient.

While oral hairy leukoplakia has been observed predominantly in patients with HIV-infection at various stages, recent reports have shown that HL may also occur in patients immunosuppressed for other reasons. This report describes oral hairy leukoplakia in a heart transplant recipient with negative HIV serology. The histopathologic diagnosis of HL was confirmed by immunohistochemical detection of EBV-VCA in the surface epithelium of the lesion and by negative staining electron microscopy.

HIV: early virus-cell interactions.

Two entry mechanisms of HIV occur in both lymphocytes and macrophages incubated with purified virus suspensions: (a) direct fusion of the viral envelope with the cell membrane and (b) receptor-mediated endocytosis via clathrin-coated pits and vesicles. Both mechanisms are shown in detail in a time-interval series of electron micrographs. The two lipid bilayers of the viral envelope and of the cellular membrane usually fuse seamlessly within 1-3 min at 37 degrees C, but occasionally membrane ruptures occur, leading to rapid cytopathic effects, i.

Characterization of immunostimulating complexes (ISCOMS) of HIV-1.

HIV-1, strain HTLV-III, propagated in H9 cells and purified by sucrose gradient centrifugation, was used as native antigen source for the preparation of immunostimulating complexes, HIV-iscoms. The major antigen detected in the iscom was the cell-derived HLA-DR, which readily could be removed from the virus lysate by immunosorbent. In the iscoms the HIV structural proteins MA p17, p55 and TM gp41 were identified; SU gp120 was present in only minute amounts in the virus lysate.

[Hyperpigmentation of the oral mucosa in HIV infection].

In ten HIV-infected patients oral hyperpigmentations (HP) were observed, which seemed to be unrelated to any of the known endogenous or exogenous etiological factors. Light microscopy revealed accumulation of Fe-negative pigment in keratinocytes of the stratum basale as well as extra- and intracellularly within the subepithelial connective tissue. The ultrastructure of HP was characterised by the occurrence of melanosomes and premelanosomes within keratinocytes, melanocytes, macrophages and occasionally in fibroblasts, while especially in keratinocytes of the superficial cell layers immature melanosomes were found.

Electron spectroscopic imaging (ESI) of viruses using thin-section and immunolabelling preparations.

Electron spectroscopic imaging (ESI) and conventional bright-field transmission electron microscopy (TEM) were applied comparatively for the analysis of the fine structure and the antigenic make-up of human immunodeficiency virus and two herpes viruses. In addition to the information obtained in conventional bright-field TEM, ESI leads to high-contrast imaging of ultrathin sections and improves the resolution of thin and thick sections, and allows a better detectability of the immunolabelling markers.

A CD 4: immunoglobulin fusion protein with antiviral effects against HIV.

Antibody-like molecules consisting of the human CD 4 extracellular domain fused to human IgG1 heavy chain constant regions were genetically constructed and expressed in a BHK cell stable transfectant. Purified chimeric antibodies bound to HIV particles as it was shown by immuno electron microscopy, inhibited fusions of HIV-1-infected cells with uninfected cells, neutralized HIV-1, and were able to inhibit the spread of a cellular HIV-1 infection in CD 4+ cells. Plaque reduction assays with CD 4(+)-transfected Hela-cells showed a comparable inhibition of HIV-1 and HIV-2.

Conserved epitopes of simian herpesvirus SA 8 and bovine herpesvirus type 2.

Some major structural components of simian herpesvirus SA 8 were analyzed and the relationship of SA 8 with HSV-1 and especially with BHV-2 was further characterized using a panel of SA 8- and BHV-2-specific monoclonal antibodies directed against gB, gD, gE, and ICP 8. It could be shown that SA 8 and BHV-2 expressed gB-1 equivalents, which differ in electrophoretic mobility, but share common epitopes with HSV-1. The antigenic determinants were detectable in the cytoplasm, on the surface of infected cells and on the virus envelope.

Quaternary structure of the immunostimulating complex (iscom).

Proteins of either HIV-1, hepatitis B, or rabies virus were incorporated with the adjuvant substance Quil A and cholesterol into the immunostimulating complex: iscom. Formation and symmetry of this regular complex were analyzed by electron microscopy. Micellar structures with a diameter of about 12 nm, occasionally with a 7-nm stain-filled center, were formed in a 0.

Ultrastructural findings in oral hyperpigmentation of HIV-infected patients.

Oral hyperpigmentation has been observed in six HIV-infected patients, in two of whom systemic medication (ketokonazole, clofazimine) was supposed to be etiologically involved. Histologically, pigment was found in epithelial basal cells and particularly in subepithelial connective tissue. Ultrastructurally, the presence of premature melanosomes in subepithelial keratinocytes was of interest.

HBcAg expressed on the surface of circulating Dane particles in patients with hepatitis B virus infection without evidence of anti-HBc formation.

Circulating immune complexes composed of HBcAg and anti-HBc have been demonstrated recently in patients with hepatitis B virus replication. After dissociation of immune complexes by chaotropic ions, HBcAg was quantified radioimmunologically. In the present study, we describe 10 patients with hepatitis B virus replication, absent or delayed anti-HBc formation and exposed HBcAg in serum.

Oral hairy leukoplakia: observations in 95 cases and review of the literature.

Oral hairy leukoplakia (HL) was observed in 25.4% of 373 HIV-seropositive patients (n = 95). 87 were men of an average age of 37.

Two interferon sensitive steps in the replication cycle of Rous sarcoma virus.

De novo infection of Rous sarcoma virus (RSV) strains of receptor subgroups A, B, C, and D is inhibited by low doses of chick interferon. Adsorption and penetration into the cell are not marginally impaired by interferon treatment. Since the level of proviral DNA synthesis is strongly reduced in the interferon-treated cell it is concluded that uncoating or reverse transcription of the viral genome is inhibited.

Oral hyperpigmentation in HIV-infected patients.

Six cases of oral hyperpigmentation in HIV-infected patients are reported. While in two patients the lesions could be related to systemic clofazimine or ketoconazole therapy, in the other patients the cause remained unknown. Clinically, the pigmentations were characterized by a sudden onset and the appearance of well-defined, brown-black macules in the buccal mucosa, the gingiva, the hard palate, or the lateral borders of the tongue.