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C Parravicini

Publications and source records attributed to C Parravicini.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1996

KSHV antibodies among Americans, Italians and Ugandans with and without Kaposi's sarcoma.

A major controversy regarding Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) is whether or not it is a ubiquitous infection of humans. Immunoassays based on KSHV- and Epstein-Barr virus (EBV)-coinfected cell lines show that most US AIDS-KS patients have specific antibodies to KSHV-related antigens. We have developed a sensitive indirect immunofluorescence assay (IFA) based on an EBV-negative, KSHV-infected cell line, BCP-1. When we used this IFA assay, KSHV-related antibodies were found in 71-88% of serum samples from US, Italian and Ugandan AIDS-KS patients, as well as all serum samples examined from HIV-seronegative KS patients. Although none of the US blood donors examined were KSHV seropositive by IFA, intermediate and high seroprevalence rates were found in Italian and Ugandan control populations. Antibody kinetics showed that more than half of the AIDS-KS patients who were examined IgG-seroconverted before KS development, and antibody levels did not decline after seroconversion. For these patients, seropositivity rates increased linearly with time, suggesting that the rate of infection was constant and that the risk of developing KS once infected with KSHV is not highly dependent on the duration of infection. These data strongly suggest that KSHV is not ubiquitous in most populations and that the virus may be under strict immunologic control in healthy KSHV-infected persons.

AIDS-Related Opportunistic Infections↗
PubMed1996

High frequency of non-Hodgkin's lymphoma in patients with HIV-associated Kaposi's sarcoma.

OBJECTIVE: To evaluate, with the support of autopsy findings, the frequency of non-Hodgkin's lymphoma (NHL) among patients with AIDS-associated Kaposi's sarcoma (KS) in comparison with that of AIDS patients with other AIDS-defining diseases. METHODS: The study involved 363 consecutive patients with AIDS who were cared for and died at the Clinic of Infectious Diseases in Milan between May 1984 and December 1992. Clinical records and autopsy data of all of the patients were retrospectively reviewed. Kaplan-Meier product-limit estimates of the time to the development of NHL were calculated for all patients and by specific subgroups. Cox proportional hazards analyses were made to determine the factors associated with the development of NHL. RESULTS: In the majority of cases (82%), KS was diagnosed during life, whereas NHL was diagnosed before death in only 41.6% of cases. Taking the autopsy data into account, the cumulative incidence of the two tumours was 16.8% for KS and 16.5% for NHL. Among the 61 patients in whom KS was the index disease of AIDS, 16 also developed NHL. The probability of developing NHL was significantly higher in patients with KS at AIDS diagnosis than in patients with Pneumocystis carinii pneumonia (PCP), oesophageal candidiasis or other AIDS-related diseases (P = 0.004). Multivariate analysis of the factors associated with the development of NHL (such as sex, age, risk factors, AIDS-defining diseases and CD4+ cell counts) showed that the patients with KS as the index disease of AIDS had a 5.3-fold higher risk of developing NHL than the patients with PCP as the primary manifestation of AIDS. CONCLUSIONS: Our results confirm the higher incidence of malignant lymphoma in patients with AIDS-KS than in patients with other AIDS-related diseases. The importance of autopsy in assessing these data is underlined by the high percentage of NHL diagnosed only after death. These observations may support the hypothesis of a common aetiological agent, or of a common pathway, for the two neoplasms.

AIDS-Related Opportunistic Infections↗
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↗