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C Parravicini

Publications and source records attributed to C Parravicini.

At least 19 recordsLinked to original sources
PubMed1996

Latent BK virus infection and Kaposi's sarcoma pathogenesis.

We have analyzed by PCR skin lesions from classic, endemic and AIDS-related Kaposi's sarcoma (KS), as well as from KS-derived cell lines, the presence of ubiquitous transforming viruses. BK virus (BKV), a transforming human papovavirus which has been associated with human tumors, was detected in 100% of KS skin lesions and 75% of KS cell lines. KS specimens contained a full-length, intact BKV early region, but minor rearrangements were observed in some tumors. BKV was also detected with a high prevalence (57-67%) in genital tissues and sperm, thus fulfilling the role of a sexually transmitted agent in KS. The closely related JC virus (JCV), which has never been associated with human malignancies, was present in 11-20% of KS specimens and was detected with a low prevalence (0-21%) in genital tissues and sperm. Simian virus 40 (SV40) was not detected in any KS lesions. Herpes simplex virus (HSV) DNA sequences were detected in 20-25% of KS lesions. Malignant human papillomavirus (HPV) types 16 and 18 and benign HPV types 6 and 11 were detected in KS specimens with a similar prevalence of 11-83%, suggesting that the presence of HPV-transforming sequences is not a specific trait of HPV interaction with KS tissue. Furthermore, JCV, SV40, HSV and HPV DNA sequences were not detected in KS cell lines, suggesting that these viruses are not associated to KS neoplastic cells in KS tissue. KS cell lines were also negative for DNA sequences of KS-HV, the novel herpesvirus detected in primary KS lesions. The constant association of BKV DNA with KS lesions and KS cell lines suggests that BKV-transforming functions may participate in the development of KS.

BK Virus↗
PubMed1996

Isolation of spindle-shaped cell populations from primary cultures of Kaposi's sarcoma of different stage.

Cell lines derived both from sporadic and epidemic KS biopsies show similar characteristics: a mixture of mesenchymal and vascular markers as well as production of factors which recruit endothelial cells in vitro and induce neoangiogenesis in vivo. Most established KS spindle cell strains are derived from patch or plaque stage KS lesions, which are easily collected during routine biopsies. Here we have characterized KS-derived spindle cell lines obtained from the four different stages typical of KS progression: angiomatous macula, patch, plaque and nodular KS to show if the similar features of our KS cell lines are linked to a particular stage of progression or to an in vitro selection/differentiation during KS cell culture. These four KS cell lines have shown the same pattern of characterization as the previous established KS cell lines, apart from an early selection of the spindle cell population we have also observed an easy inducible phenotypic differentiation through a myofibroblastic spindle cell type simply plating cells on gelatin-coated flasks. These data confirm the hypothesis of spindle cell selection in culture and the possible differentiation of these mesenchymal cells.

Adult↗
PubMed1995

Heterogeneity of spindle cells in Kaposi's sarcoma: comparison of cells in lesions and in culture.

The immunophenotype of spindle cells in epidemic, endemic, and classic (sporadic) Kaposi's sarcoma (KS) lesions was defined by the demonstration of various cell markers and compared with that of KS-derived cell lines. No significant histological or immunophenotypic differences were observed between the three clinical types of KS at comparable stages. The spindle-cell compartment of the different KS types was composed predominantly of a mixture of proliferating CD45+/CD68+ bone-marrow-derived monocytes and TE7+/collagen+ fibroblastic cells with varying expression of EN4/PAL-E/CD31/CD34/CD36 endothelial-associated antigens and/or smooth-muscle-specific alpha-actin (alpha-actin). The latter cells appeared to represent transitional forms of fibroendothelial and fibromyocytic cells. The in vitro cultured KS-derived cell lines (KS-3, KS-6, and KS-8) expressed the fibroblastic antigen TE7 and smooth-muscle-specific alpha-actin but not leukocytic or endothelial-associated antigens consistent with the phenotype of fibromyoid spindle cells of primary lesions. Neither HIV antigen nor provirus DNA was demonstrable in the epidemic KS lesions. The observed heterogeneity of the spindle-cell compartment further substantiates the view that Kaposi's sarcoma, irrespective of clinical setting, expresses salient features more compatible with reactive, tumor-like lesion than clonal sarcoma.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Tuberculosis cutis miliaris disseminata due to multidrug-resistant Mycobacterium tuberculosis in AIDS patients.

Two patients with AIDS and disseminated tuberculosis characterized by cutaneous involvement are reported. They developed a maculopapular skin eruption, from which a multidrug-resistant Mycobacterium tuberculosis strain was isolated. In both cases the clinical course was rapidly fatal. Tuberculosis cutis miliaris disseminata should be differentiated from the skin lesions frequently seen in HIV-infected patients, especially from folliculitis. In patients with tuberculosis, the appearance of cutaneous lesions may be due to the haematogenous dissemination of mycobacteria. Therefore, early identification of the causative organism by use of optimal microbiological methods is fundamental.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Frequent detection of antibodies against HTLV antigens in patients with AIDS-related non-Hodgkin lymphoma.

We studied the prevalence of anti-HTLV-I/II antibodies in 22 patients with AIDS-related non-Hodgkin lymphoma (NHL), 453 HIV-1-infected patients without lymphoma (194 of whom were diagnosed as having AIDS), and 6 HIV-1-positive and 75 HIV-1-negative patients with Hodgkin lymphoma. The frequency of serological reactivity against HTLV antigens was significantly higher in the AIDS patients with lymphoma than in those without (8 of 22, 36.4% vs. 20 of 194, 10.3%-p = 0.0027). One of the HIV-1-positive and none of the HIV-1-negative patients with Hodgkin lymphoma showed anti-HTLV-I/II reactivity. Four of the eight seropositive NHL patients showed antibodies directed against HTLV-II recombinant antigens when tested for serological discrimination in a Western blot assay. A PCR study of PBMCs from the only patient with NHL still alive at the time of the study showed HTLV-II-specific sequences in the genomic DNA. These data suggest that HTLV-II or a closely homologous retrovirus infects a high proportion of patients with AIDS-associated NHL.

Adult↗
PubMed1995

High prevalence of human T cell lymphotropic virus type II infection in patients affected by human immunodeficiency virus type 1--associated predominantly sensory polyneuropathy.

The etiopathogenesis of peripheral neuropathy (PN) that frequently affects human immunodeficiency virus (HIV) type 1-positive patients remains undefined. Forty-seven HIV-1-positive patients with PN (8 with inflammatory demyelinating polyneuropathy and 39 with predominantly sensory polyneuropathy [PSP]) and 266 controls with symptomatic HIV-1 infection without PN were screened for antibodies to human T cell lymphotropic virus (HTLV) types I and II. The prevalence of antibodies to HTLV-II was significantly higher in patients with PSP than in controls (30.8% vs. 8.3%; P < .001). All seropositive patients with PN had HTLV-II DNA in their peripheral blood mononuclear cells by polymerase chain reaction (PCR) analysis. PCR analysis of tissues from 1 patient with PSP who died during the study showed HTLV-II proviral sequences in the femoral nerve and basal nuclei. These results support the hypothesis that HTLV-II represents an etiologic factor in the pathogenesis of a considerable proportion of PSP in patients infected with HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Progressive growth in immunodeficient mice and host cell recruitment by mouse endothelial cells transformed by polyoma middle-sized T antigen: implications for the pathogenesis of opportunistic vascular tumors.

A retroviral construct encoding polyoma middle-sized T antigen was used to generate transformed endothelial cell lines from heart (H5V), brain (B9V), and whole-embryo (E10V) of C57BL/6 mice. When injected into syngeneic recipients, H5V and the less studied B9V and E10V cells caused vascular tumors which, depending on the number of cells inoculated, regressed or progressed, leading to death of the host. When H5V cells were injected into immunodeficient mice, tumors were observed with inocula which did not form lesions in immunocompetent recipients and regression did not occur. Treatment with anti-LFA-1, anti-Thy-1.2, and anti-CD8 antibodies abolished rejection; anti-CD4 was a somewhat less effective inhibitor of resistance. Animals with progressive tumors exhibited secondary lesions in various organs with prominent skin involvement in nude mice. Histologically, the tumors had the appearance of a hemangioma, with areas resembling Kaposi sarcoma. Cells lining vascular lacunae had the morphological features of injected H5V cells. The lesions were characterized by prominent neovascularization and mononuclear cell infiltration. Southern blot hybridization analysis revealed that approximately 5% of the cells in the tumor mass were transplanted H5V cells. Thus, the H5V transformed endothelial line causes vascular lesions that are sustained to a large extent by recruitment of host cells and manifests full malignant behavior only in immunocompromised hosts. The hypothesis of a tumor sustained by a minute proportion of transformed cells, which recruit host elements and express full malignant behavior only in immunodeficient hosts, would account for several features of some vascular neoplasms in man.

Animals↗
PubMed1993

Epstein-Barr virus DNA in cerebrospinal fluid from patients with AIDS-related primary lymphoma of the central nervous system.

Epstein-Barr virus (EBV) is constantly associated with AIDS-related primary lymphomas of the central nervous system (CNS). To assess whether EBV DNA in cerebrospinal fluid (CSF) could be used as a tumour marker, CSF samples that had been taken within 180 days before death from 85 patients with HIV infection and neurological disorders at necropsy were examined retrospectively by nested polymerase chain reaction (PCR) for EBV. Histologically evident primary CNS lymphomas were found in 17 patients, and EBV was shown in tissue by in-situ hybridisation in 16 of the 16 cases examined. All 17 patients with primary CNS lymphoma had EBV DNA in CSF. EBV DNA was found in CSF from 1 of 68 HIV-infected patients without histologically detectable lymphoma at necropsy. PCR for EBV DNA in CSF was 100% sensitive and 98.5% specific for AIDS-associated primary CNS lymphoma, and may be useful as a diagnostic tumour marker.

Base Sequence↗
PubMed1993

Antigen unmasking on formalin-fixed, paraffin-embedded tissue sections.

Enzymatic and non-enzymatic treatments for antigen unmasking on formalin-fixed, paraffin-embedded, dewaxed sections were optimized and compared by the use of a panel of antibodies of diagnostic relevance (anti-cytokeratins, vimentin, S-100, T- and B-cell receptors, Ki-67/MIB 1, muscle actin). Non-enzymatic unmasking was obtained by boiling the slides in a microwave oven in 0.01 M salt solution (pH 6) or in 6 M urea. Trypsin or pronase digestion was used for comparison and found to be necessary for some of the reagents. The investigation was then extended to 256 antibodies; the epitopic amino acid sequence was known for 48 of them. We found that enzymatic and non-enzymatic antigen unmasking are not dependent on the epitope sequence, but some antigens benefit selectively from one treatment but not from the other. Denaturation of proteins is the likely mechanism which leads to immunodetection on microwave oven-boiled slides; this suggestion is supported by the use of denaturating solutions and by the observation that endogenous enzymes were inactivated and a few antigens were no longer immunodetectable after boiling. Non-enzymatic methods for antigen unmasking are a powerful new tool for broadening the use of antibodies for immunostaining formalin-fixed, paraffin-embedded sections and should be used in parallel with the traditional enzymatic methods.

Antibodies↗
PubMed1992

Spindle cell ploidy and proliferation in endemic and epidemic African Kaposi's sarcoma.

Comparative studies of ploidy and proliferative activity of spindle cells in sections of 20 (skin, 17; lymph node, 3) biopsy specimens from African patients, 10 with endemic Kaposi's sarcoma (EKS) and 10 with AIDS-associated Kaposi's sarcoma (AKS) were performed by histopathology, feulgen-based DNA measurement and proliferating cell nuclear antigen (PCNA)/cyclin immunohistochemistry, respectively. All specimens were classified as nodular lesions with basically the same histology. In 17 cases immunostained for cyclin/PCNA, the percentage of proliferating spindle cells range between 2-18, with a higher mean rate in AKS although this was not statistically significant. In situ measurement of DNA showed no significant values greater than the diploid level of control cells indicating that spindle cells in both EKS and AKS have euploid DNA content. Our findings indicate that both EKS and AKS represent the same type of euploid low rate cell proliferations. This corroborates previous suggestions that KS could represent a reactive process to yet undefined stimulus rather than a clonal proliferation, of transformed malignant cells.

Adult↗
PubMed1992

Macrophage association of polyomavirus in progressive multifocal leukoencephalopathy: an immunohistochemical and ultrastructural study. Case report.

Progressive multifocal leukoencephalopathy (PML) in a patient following autologous bone marrow transplantation for a non-Hodgkin's centroblastic lymphoma was studied by immunohistochemistry and transmission electron microscopy. Our observations indicate that a large amount of polyomavirus, most probably JC virus, is taken up and segregated within vacuoles of macrophages by phagocytosis. A relevant role of macrophages in the pathogenesis of PML is emphasized.

Brain↗
PubMed1992

Hypophyseal pathology in AIDS.

One hundred and eleven pituitary glands of patients (93 males, 18 females; mean age 32 years, 5 months) who died of fully developed AIDS or ARC were examined under light microscopy with the aid of immunohistochemistry. On post mortem (p.m.) examination a wide series of multiorgan alterations was noticed. Microscopically various lesions in both adeno- and neurohypophysis were seen. These ranged from vessel damage to secondaries to systemic infections, neoplasms and functional derangements. Necrotic lumps due to recent infarction could appear in both parts of the gland, while old fibrous scars sustained a previously overcome necrosis. Different pathogens (mainly fungi) could be seen either within the gland or arising from its meningeal surroundings. Examples of tumour pathology were provided by microadenomas, gliosis/gliomas; the frequency of adenomas (11.7%) was similar to that typical of senility. The functional impairment was mainly connected with ACTH cell hyperplasia, which seems in keeping with corticoadrenal or ACTH-receptor damage.

AIDS-Related Complex↗