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Biomedical subjects

M Boiocchi

Publications and source records attributed to M Boiocchi.

At least 91 records · Page 5Linked to original sources
PubMed1996

Detection and distribution of hepatitis C virus-related proteins in lymph nodes of patients with type II mixed cryoglobulinemia and neoplastic or non-neoplastic lymphoproliferation.

The role of hepatitis C virus (HCV) in the pathogenesis of type II mixed cryoglobulinemia (MC) has been strongly emphasized in the last few years. Although MC is a benign lymphoproliferative disorder, the risk of overt B-cell malignancy greatly increases during its course. The occurrence of HCV infection in 10% to 30% of patients with non-Hodgkin's lymphoma (NHL) suggests that this virus may have a role in the development of MC-associated B-cell malignancies. We identified 2 patients with hyperplastic reactive lymphadenopathy (HRL) and 12 with NHL in two series of MC patients chronically infected with HCV collected over a 5-year period. Structural and nonstructural HCV-related proteins were investigated in lymph node sections by immunohistochemistry and their location and distribution were correlated with clinical and histologic findings, viremic state, and HCV genotypes. In HRL, HCV proteins were found in the cytoplasm of lymphoid cells, mainly in interfollicular areas. However, occasional positive cells were found in the mantle zone and in the germinal centers of follicles. In addition, strong reactivity was found in the circulating mononuclear cells of capsular blood vessels. HCV immunodeposits were found in 3 of 12 (25%) NHL cases. Positive cells were frequently restricted to the cortex; if not, they were randomly diffused in the neoplastic tissue. Positivity was related to the low-grade type of NHL; in the 2 composite cases, HCV immunodetection was found in the small cells, whereas large anaplastic cells were regularly negative. Other viruses previously involved in lymphoproliferation, ie, human herpes virus-6 and Epstein-Barr virus, were absent in all tissues. These data emphasize that lymphoid organs may be a site of HCV infection. The demonstration of HCV-related proteins in a nonmalignant condition, namely HRL, indicates that HCV infection precedes the neoplastic transformation and possibly plays a major role in lymphomagenesis in MC.

Adult↗
PubMed1996

Determination of unbound etoposide concentration in ultrafiltered plasma by high-performance liquid chromatography with fluorimetric detection.

Etoposide is a highly protein bound drug, and monitoring the concentration of free drug could help individualize dosage in oncological patients. The cost and difficulty of the standard techniques (equilibration dialysis) has hampered the monitoring of free drugs. We describe a simple HPLC method for the measurement of free etoposide concentration in plasma. Sample preparation involves the ultrafiltration of plasma by a Centrifree device for 30 min at 2000 g and extraction with chloroform. The isocratic separation is performed with a mu Bondapak phenyl analytical column. Fluorimetric detection is used (288-328 nm excitation and emission wavelengths). Linearity of the calibration curve is excellent between 0.05 and 1 microgram/ml. Accuracy and precision are reported at the concentrations 0.06 and 0.4 microgram/ml: within-run accuracy is 10% and 6.2%, respectively; between-run accuracy is < or = 1%; within-run coefficients of variation (C.V.) are 10.6 and 5.0%; between-run C.V. are 11.6 and 6.8% respectively. The range of the assay is 0.05 to 1 microgram/ml. The feasibility of the technique has been tested in 7 patients treated with oral etoposide for hepatocarcinoma (mean protein binding 91%). We found no interference from endogenous substances, co-administered drugs (alizapride, furosemide, ranitidine) and other antineoplastic agents (doxorubicine, idarubicine, vinblastine, vinorelbine).

Aged↗
PubMed1996

Retinoids irreversibly inhibit in vitro growth of Epstein-Barr virus-immortalized B lymphocytes.

Natural and synthetic retinoids have proved to be effective in the treatment and prevention of various human cancers. In the present study, we investigated the effect of retinoids on Epstein-Barr virus (EBV)-infected lymphoblastoid cell lines (LCLs), since these cells closely resemble those that give rise to EBV-related lymphoproliferative disorders in the immunosuppressed host. All six compounds tested inhibited LCL proliferation with no significant direct cytotoxicity, but 9-cis-retinoic acid (RA), 13-cis-RA, and all-trans-RA (ATRA) were markedly more efficacious than Ro40-8757, Ro13-6298, and etretinate. The antiproliferative action of the three most effective compounds was confirmed in a large panel of LCLs, thus appearing as a generalized phenomenon in these cells. LCL growth was irreversibly inhibited even after 2 days of treatment at drug concentrations corresponding to therapeutically achievable plasma levels. Retinoid-treated cells showed a marked downregulation of CD71 and a decreased S-phase compartment with a parallel accumulation in Gzero/ G1 phases. These cell cycle perturbations were associated with the upregulation of p27 Kip1, a nuclear protein that controls entrance and progression through the cell cycle by inhibiting several cyclin/cyclin-dependent kinase complexes. Unlike what is observed in other systems, the antiproliferative effect exerted by retinoids on LCLs was not due to the acquisition of a terminally differentiated status. In fact, retinoid-induced modifications of cell morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and increased expression of CD38 and c-Ig), and IgM production were late events, highly heterogeneous, and often slightly relevant, being therefore only partially indicative of a drug-related differentiative process. Moreover, EBV-encoded EBV nuclear antigen-2 and latent membrane protein-1 proteins were inconstantly downregulated by retinoids, indicating that their growth-inhibitory effect is not mediated by a direct modulation of viral latent antigen expression. The strong antiproliferative activity exerted by retinoids in our experimental model indicates that these compounds may represent a useful tool in the medical management of EBV-related lymphoproliferative disorders of immunosuppressed patients.

Antigens, CD↗
PubMed1996

Cellular pharmacology of idarubicinol in multidrug-resistant LoVo cell lines.

Idarubicin (IDA) is a daunorubicin (DAU) analog that is being used to treat a variety of human malignancies. The major circulating metabolite of IDA is idarubicinol (IDOL). After administration of IDA to patients, the systemic exposure to IDOL is greater than IDA. We investigated the cytotoxic effect of IDOL in the LoVo human colon-carcinoma cell line and its derivative multidrug-resistant (MDR) sub-lines. In LoVo-sensitive cells, the extracellular IDOL concentration inhibiting cell growth by 50% (IC50) was about 2-fold higher than IDA IC50 but lower than DAU IC50. After continuous exposure of the LoVo parental cells to 20 nM IDOL, 5 drug-resistant clones were obtained. All these clones exhibited an MDR phenotype, indicating that IDOL is involved in multidrug resistance. The resistance index (RI) to IDOL was investigated in LoVo MDR sub-lines obtained by IDOL (LoVo-IDOL-1), IDA (LoVo-IDA-1) and DOX (LoVo-DOX-1) selection. In spite of the drug used for their selection, all the MDR sub-lines exhibited an RI to IDOL lower than DAU and only 2-fold higher than IDA. In LoVo-IDOL-1 cells the RI was 5, 11 and 32 for IDA, IDOL and DAU respectively. Differences in the RI were explained by the greater intracellular tolerance exhibited by MDR cells to DAU than to IDOL and IDA. In the LoVo-IDOL-1 sub-line, the intracellular drug concentration inhibiting cell growth by 50% (IC50int) was higher than in the sensitive cells by 11.4-, 4.7- and 2.8-fold for DAU, IDOL, and IDA respectively. Differences in the intracellular tolerance were explained by the different intracellular distribution of DAU compared with IDOL and IDA. While DAU had a higher nuclear location in LoVo-sensitive cells than in resistant cells, IDOL and IDA maintained the same distribution both in sensitive and in resistant cells. In conclusion, contrary to what has been observed for other derivative metabolites of anthracyclines, the metabolism of IDA to IDOL must not be considered an inactivation pathway. IDOL is a potent inhibitor of cell growth and retains good activity in MDR cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Chromosome 13q deletion mapping in head and neck squamous cell carcinomas: identification of two distinct regions of preferential loss.

Heal and neck squamous cell carcinomas show frequent cytogenetic alterations involving the long arm of chromosome 13. To define the extent of 13q deletions and to identify the minimal areas of chromosome loss, 48 primary squamous cell carcinomas of the head and neck were analyzed for loss of heterozygosity using 11 different polymorphic loci. About 67% of the tumors displayed loss of genetic material at 13q. Most of the cases showed loss of the entire long arm of the chromosome. However, the presence of partial deletions in 10 cases provided evidence of the existence of two preferential sites of chromosome loss at 13q32-ter and 13q14.2-q14.3. The colocalization of the 13q14 minimal region of deletion with the retinoblastoma (RB) gene, which has been proposed as an oncosuppressor in diverse tumor types, prompted us to verify the involvement of this gene in the development of head and neck cancer. No significant variation in RB protein or RB mRNA expression was detected, thus excluding a role for such a gene in the genesis of this type of tumor. Taken together, our data suggest the existence of two new tumor suppressor genes (one close to and one distal to RB), which play a role in the development and/or progression of head and neck squamous cell carcinomas.

Base Sequence↗
PubMed1996

Human herpesvirus 6 in human immunodeficiency virus-infected individuals: association with early histologic phases of lymphadenopathy syndrome but not with malignant lymphoproliferative disorders.

Preliminary evidence suggested that human herpesvirus-6 (HHV-6) may act as a cofactor in acquired immunodeficiency syndrome (AIDS) and may contribute to the pathogenesis of lymphoproliferative disorders occurring in individuals infected with the human immunodeficiency virus (HIV). To understand better the biological and clinical significance of HHV-6 infection in the context of HIV-related immunosuppression, the polymerase chain reaction was used to study the frequency and variant distribution of HHV-6 in peripheral blood mononucleated cells (PBMCs) from HIV-seropositive individuals, either asymptomatic or with lymphadenopathy syndrome (LAS) or with overt AIDS. Non-neoplastic and malignant lymphoproliferative disorders from both HIV-infected and HIV-seronegative patients were also investigated using the same series of samples for the presence of Epstein-Barr virus (EBV). When compared with healthy blood donors (12/42, 29%), HHV-6 prevalence in PBMCs showed a progressive decline in HIV-seropositive individuals with asymptomatic HIV infection (3/26, 11%) and in patients with LAS (1/13, 8%) and a significant reduction in patients with overt AIDS (1/20, 20%; P = 0.02). The decrease correlated with the number of CD4+ cells at the time of examination. In addition, HHV-6 DNA sequences were significantly more prevalent in LAS biopsies (13/20, 65%) than in HIV-unrelated reactive lymphadenopathies (2/10, 20%; P = 0.02) and the presence of HHV-6 sequences correlated closely with a histologic pattern of follicular hyperplasia (13/16, 81%; P = 0.003). Strikingly, HHV-6 prevalence decreased in PBMCs of LAS patients, suggesting that the likelihood of interactions between HHV-6 and HIV varies in different body districts. In particular, the demonstration that all HHV-6-carrying LAS samples were also positive for HIV infection suggests that LAS lymph nodes constitute one of the sites where biologically relevant interactions between the two viruses might occur. Also, the prevalence of EBV was higher in LAS (14/20, 70%) than in non-neoplastic lymph nodes from HIV-seronegative individuals (4/10, 40%), although the difference was not statistically significant. EBV was associated strongly with HIV-related malignant lymphoproliferative disorders, being detected in 100% of patients with Hodgkin's disease (HD) and 53% of B-cell non-Hodgkin's lymphomas (NHL). In contrast, the prevalence of HHV-6 DNA in HD and B-cell NHL arisen in HIV-infected patients (30% and 6% respectively) was remarkably lower and similar to that observed in lymphoproliferative disorders from HIV-seronegative patients. Finally, as observed in healthy individuals, HHV-6 variant B was more prevalent than variant A in benign and malignant lymphoproliferative disorders from bot HIV-infected and HIV-seronegative patients. These results suggest that the interactions between HHV-6 and HIV could be different in the various phases of HIV disease and in different districts; HHV-6 has probably no direct role in the pathogenesis of HIV-associated B-cell NHL and HD cases, and behave differently from EBV; and HIV-related immunosuppression does not alter the distribution of HHV-6 variants in these tissues, as observed in the case of EBV.

AIDS-Related Complex↗
PubMed1996

Long-term survival of patients with HIV-related systemic non-Hodgkin's lymphomas.

BACKGROUND: the overall outcome of patients with HIV-related non-Hodgkin's lymphomas (HIV-NHL) is poor because of the adverse clinico-pathological features of HIV-NHL and the underlying HIV infection. However, the experience of physicians in the management of HIV-NHL has increased, in particular in the use of intensive chemotherapy regimens, leading to an improvement in the prognosis of some of these neoplasms. Because some patients with AIDS may survive up to 5 years, it is possible to evaluate the long-term efficacy of the treatment of patients with HIV-NHL. In the general population, aggressive NHL, that are those occurring in HIV patients, may be considered cured after 2 years of lasting complete remission (CR) after chemotherapy. PATIENTS AND METHODS: we reviewed our monoinstitutional case-series of 73 HIV-infected patients with systemic NHL, observed between April 1985 and February 1993. Two groups of patients were arbitrarily identified, the first one (group A) including patients with a CR lasting for at least 2 years (N = 13) and the other including all remaining patients (group B) (N = 60). RESULTS: the 13 patients of group A differed significantly from the other patients in terms of higher CD4+ cell count and performance status (PS) at the time of diagnosis of NHL. There was no significant difference in the histological subtypes of the HIV-NHLs. The overall survival of the 73 patients was 8 months. In a separate analysis on all patients, age less than 30 years, PS less or equal to 1, a CD4+ cell count equal to or higher than 100/mm3 and the absence of B symptoms were significantly associated with a longer survival. The median survival in patients of group A was 42 months, however none of these patients relapsed during a median observation time of 42 months (range, 24-90). CONCLUSIONS: long-term survival and possibly cure can be obtained in some patients with HIV-NHL, in particular in those with a better PS and a less advanced immune dysfunction. In fact some of these patients are alive without evidence of disease 4 to 7 years after therapy, and others died of causes related to underlying HIV infection, in particular opportunistic infections, rather than relapse of NHL.

Adult↗
PubMed1996

Inhibition of Pgp activity and cell cycle-dependent chemosensitivity to doxorubicin in the multidrug-resistant LoVo human colon cancer cell line.

To determine whether the cell cycle affects multidrug resistance (MDR) and its reversal, doxorubicin (DOX) cytotoxicity and the effect of inhibition of P-glycoprotein (Pgp) activity by verapamil (VER) were investigated in MDR LoVo cell lines (LoVo-R) in different phases of the cell cycle. Synchronised cells were obtained by exposing cells for 24 h to non-toxic concentrations (40 nmol/l) of methotrexate (MTX), which induced a reversible blockade in the S phase. DOX cytotoxicity was higher if cells were exposed to DOX shortly after the pretreatment with MTX, when most cells were in the S phase of the cell cycle. At that time, the DOX concentration inhibiting cell growth by 50% (IC10) was decreased by approximately 4-fold compared to non-synchronised cycling cells. DOX cytotoxicity remained high during the transition from the S to the G2M phase, but was reduced when the cells had shifted to the G2M phase. Inhibition of Pgp activity by VER (6 mumol/l) enhanced DOX uptake and resulted in an intracellular nuclear compartmentalisation of DOX in LoVo-R cells. These effects were not significantly different (P = NS) in the different phases of the cell cycle. However, similar increases in intracellular DOX uptake due to the inhibitory effect of VER on Pgp greatly potentiated DOX cytotoxicity in LoVo-R cells synchronised in the S or G2M phase compared with non-synchronised cycling cells. The ratio between DOX IC50 in the absence and presence of VER in LoVo-R cells synchronised in the S phase and in cycling cells was 11.1 and 4.1, respectively (P < 0.01). This greater potentiation could be explained by the increased chemosensitivity of the S- and G2M-phase cells to intracellular DOX concentration compared with the non-synchronised cells. Finally, the combination of synchronisation by MTX and of inhibition of Pgp activity by VER produced a considerable reduction in DOX IC50 (approximately 50-fold) in LoVo-R cells compared with the cells not treated with MTX and VER. In conclusion, this study demonstrates that, in LoVo-R cells, the effect of Pgp inhibition on DOX cytotoxicity is dependent on cell cycle phase. DOX cytotoxicity is maximal when inhibition of Pgp activity occurs during the S/G2M phases.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Immunophenotypic and molecular analyses of acquired immune deficiency syndrome-related and Epstein-Barr virus-associated lymphomas: a comparative study.

Limited information is current available on the molecular and immunophenogenotypic characteristics of CD30-positive anaplastic large cell (ALC) lymphomas occurring in human immunodeficiency virus (HIV)-infected individuals. To address this issue, the authors have undertaken a combined analysis of these lymphomas in a comparison with other Epstein-Barr virus (EBV)-associated tumors in the setting of HIV infection. Twenty-one AIDS-related lymphomas, including five CD30-positive ALC and 11 small noncleaved cell (SNCC) lymphomas, and five Hodgkin's disease (HD) specimens were characterized regarding the immunophenogenotypic features, the frequency and subtype distribution of EBV (as defined by in situ hybridization [ISH], Southern blot, and a polymerase chain reaction [PCR] amplification of the EBV nuclear antigen-2 [EBNA-2] region) antigen expression (latent membrane protein-1 [LMP-1], EBNA-2, and for alterations of the tumor suppressor gene p53. Combined immunophenotypic and immunogenotypic analyses showed a derivation from anomalously matured B cells in four of five CD30-positive ALC lymphomas, whereas SNCC showed features of mature B cells; no evidence of immunoglobulin or TCR gene rearrangement could be obtained in HD cases. Combined ISH and Southern blot analyses revealed that EBV was more strictly associated with HD (five of five) and CD30-positive ALC lymphomas (four of five) than with SNCC lymphomas (four of 11). EBV-positive samples from CD30-positive ALC lymphomas carried type 1 EBV (two of two specimens tested), whereas both EBV subtypes were observed in SNCC lymphomas and HD samples. All three forms of viral latent gene expression were found in the EBV positive CD30-positive ALC lymphomas. SNCC specimens did not express LMP-1 or EBNA-2, whereas HD specimens expressed LMP-1 (four of five tested) but no EBNA-2. Immunostaining for ZEBRA was consistently negative. HHV-6 DNA sequences were detected by PCR in one SNCC of the 19 specimens analyzed. Three out of five CD30-positive ALC lymphoma specimens and six of 10 SNCC showed nuclear staining for p53. No mutation was detected in any of the three CD30-positive Alc lymphoma analyzed, whereas an aberrant SSCP pattern was found in all the four SNCC samples tested. At variance with SNCC lymphomas, AIDS-related B-cell CD30- positive ALC lymphomas are strictly associated with EBV infection and may also express the broad lymphoblastoid cell line-like (LMP-1-positive, EBNA-2-positive) pattern, and lack p53 genetic lesions. Unlike EBV, HHV-6 probably does not represent a relevant factor involved in the pathogenesis of CD30-positive ALC and other HIV related lymphomas.

Adult↗
PubMed1996

Widespread clonal B-cell disorder in Sjögren's syndrome predisposing to Helicobacter pylori-related gastric lymphoma.

Helicobacter pylori has been identified as a critical antigenic stimulus to the development of gastric lymphoma, but additional factors should be required for such evolution. This topic is now of major importance to clarify the pathobiology of gastric lymphomagenesis. Peculiar autoimmune diseases, such as Sjögren's syndrome, are well known to predispose to B-cell lymphomas. We report on a patient with Sjögren's syndrome and a widespread B-cell lymphoproliferative disorder. A pathological picture of low-grade lymphoma was observed in the stomach, concomitantly with H. pylori infection. However, the B-cell disorder was definitely nonmalignant in the other tissues involved, i.e., the parotid gland and lymph nodes, which are the characteristic targets of Sjögren's syndrome-associated lymphoproliferation. After H. pylori eradication, a dramatic regression of gastric lymphoma into chronic gastritis was observed, but no amelioration occurred in the parotid and nodal involvement. Multiple molecular analyses showed the expansion of the same B-cell clone in synchronous and metachronous lymph node, parotid, and gastric lesions before and after H. pylori eradication. Thus, H. pylori played a crucial role in the local boosting of B-cell lymphoproliferation, but the underlying B-cell disorder was that associated with the autoimmune disease and was nonmalignant. The comprehensive clinical, pathological, and molecular approach allowed us to then distinguish the role of peculiar individual predisposing factors and of local infection in the pathobiology of mucosa-associated lymphoid tissue-associated lymphoproliferation.

Aged↗
PubMed1996

Human herpesvirus 8 is present in the lymphoid system of healthy persons and can reactivate in the course of AIDS.

In this study the prevalence of human herpesvirus (HHV) 8 DNA was determined in biopsies from persons with lymphoproliferative disorders and in peripheral blood mononuclear cells (PBMC) from human immunodeficiency virus (HIV)-seronegative and HIV-infected persons. The results show that HHV-8 is present in 10% of biopsies from HIV-seronegative persons: HHV-8 is detected with similar prevalence values in HIV-infected patients with lymphoproliferative diseases, but the virus load is higher. HHV-8 was also found in PBMC. The presence of monoclonal Epstein-Barr virus (EBV) genomes in malignant lymphoproliferations was only infrequently associated with HHV-8 infection. Therefore, HHV-8 is fairly common in the population, and the lymphoid system could represent a reservoir of latently infected cells from which the virus may reactivate in conditions of immunodepression; furthermore, HHV-8 and EBV do not seem to act in conjunction in lymphomagenesis.

AIDS-Related Opportunistic Infections↗
PubMed1996

B cell clonality in gastric lymphoid tissues of patients with Sjögren's syndrome.

OBJECTIVE: To determine the prevalence of mucosa associated lymphoid tissue (MALT) in the stomach and of a possible antigen driven proliferation, in patients with Sjögren's syndrome (SS). METHODS: Twenty one patients with primary SS and 80 dyspeptic controls underwent upper endoscopy. Lymphoid tissue and Helicobacter pylori were assessed by histopathological analysis. Epstein-Barr virus (EBV) or human herpes virus-6 (HHV-6) genome were studied by polymerase chain reaction (PCR) DNA amplification. Two PCR VDJ procedures were used to detect immunoglobulin heavy chain (IgH) gene rearrangement. RESULTS: Organised MALT was found in 33.3% of the patients, compared with 21.5% of the controls (NS). H pylori infection was seen in 71% of patients and 63% of controls. Genomic EBV or HHV-6 was found in a minor portion of SS gastric tissues. B cell expansion was detected in nine of the 21 patients. Infectious agents in the stomach might have contributed to B cell clonality only in 55.5% of the cases. No strict relationship was found between lymphoid follicles and clonality. CONCLUSION: Lymphoid accumulation in the gastric mucosa is common in Sjögren's syndrome, but full evidence for an antigen driven B cell expansion could not be demonstrated. Only a portion of those with clonal B cell expansion had evidence of an infectious agent. Other unknown infectious agents or factors related to the underlying disease (autoantigen) and its tissue environment may have a further role as possible causes of B clonal expansion in the gastric mucosa.

Adult↗
PubMed1996

B-cell clonality and infection with Helicobacter pylori: implications for development of gastric lymphoma.

BACKGROUND: Although Helicobacter pylori has been implicated in the pathogenesis of gastric mucosa associated lymphoid tissue (MALT) and MALT lymphoma, it is not known how it may trigger these lesions and whether there is an identifiable pre-neoplastic stage. AIMS: To investigate the relation between MALT, H pylori infection, and B-cell clonality (a potential marker of pre-neoplastic lesions). PATIENTS: 141 subjects with simple dyspepsia. METHODS: Gastric biopsy specimens from all patients were examined for MALT and H pylori. Of these, 25 consecutive MALT positive specimens were scored for features of MALT lymphoma and VDJ clonality studied by polymerase chain reaction. RESULTS: Overall, prevalence was 62% for H pylori and 46% for MALT. VDJ clonality was frequent in the sub-group studied (nine of 25), mostly associated with lymphoid follicles (eight of nine or 89%), and with a high scoring for MALT lymphoma. VDJ clonality was equally frequent in patients with and without H pylori (seven of 20 and two of five or 35% and 40% respectively). CONCLUSIONS: B-cell clonality is unexpectedly common in subjects with simple dyspepsia and MALT raising clinical management questions. These findings also suggest that the cascade MALT formation--B-cell clonality--MALT lymphoma may not be uniquely associated with H pylori infection.

Adolescent↗
PubMed1996

Tumor suppressor genes and related molecules in leiomyosarcoma.

Soft tissue sarcomas represent a heterogeneous group of mesenchymal malignancies, and the majority of the previous scientific studies that have analyzed the occurrence of cell cycle regulators aberrations within soft tissue sarcomas have dealt with broad categories of different tumors. As a consequence, data concerning single classes of sarcomas are very limited. The authors analyze herein a histologically homogeneous series of 23 cases of leiomyosarcoma of the deep soft tissue. The p53 pathway was studied by investigating the p53 gene and protein, MDM2 protein, and p21waf1 protein. The Rb-cyclin D pathway was analyzed by studying the Rb gene and protein, p16MTS1/INK4A gene and protein, cyclin D1Prad1/bcl1 and cyclin D3 proteins. Aberrations of the p53 pathway were observed in about 16 percent of cases and were limited to the p53 gene. Such a finding contrasts with the higher rates of p53/MDM2 abnormalities reported in other types of sarcomas such as liposarcoma. Interestingly, abnormalities involving the Rb-cyclin D pathway were detected in about 90 percent of cases. The Rb-cyclin D pathway therefore emerges as the preferred target for molecular abnormalities in this subset of soft tissue sarcomas.

Base Sequence↗
PubMed1995

Characteristics of EBV-infected cells in HIV-related lymphadenopathy: implications for the pathogenesis of EBV-associated and EBV-unrelated lymphomas of HIV-seropositive individuals.

The present study was performed with the aim of better defining the possible role of Epstein-Barr-virus (EBV)-infected cells in the pathogenesis of HIV-related lymphadenopathy syndrome (LAS). In addition, since LAS has been considered as a pre-lymphomatous lesion, we also wished to elucidate the possible contribution of EBV-carrying cells present in LAS tissues to the development of HIV-associated malignant lymphomas. To this end, we have characterized EBV-infected cells in LAS lymph nodes in terms of EBV DNA prevalence, tissue distribution in relation to HIV-carrying cells, virus sub-type, expression of latent and replicative antigens, and presence of clonal EBV episomes. When compared with HIV-unrelated lymphadenopathies (4/10, 40%), LAS showed a higher prevalence of EBV DNA (14/20, 70%). Comparable values of EBV prevalence were detected in LAS with follicular hyperplasia (12/16, 75%) and with follicular involution (4/4, 100%). All EBV+ non-neoplastic lymph nodes from HIV-seronegative patients carried type-I EBV, whereas LAS specimens showed almost equivalent distribution of the 2 EBV sub-types. Of the 14 EBV-carrying LAS, 4 (29%) were positive by Southern-blot analysis for the BamHI-W region of the virus genome but negative for the presence of monoclonal EBV episomes. In situ hybridization revealed a remarkably higher load of EBV-infected cells in LAS than in HIV-unrelated lymphadenopathies. In LAS lymph nodes, EBV-carrying cells were identified as isolated, cytologically normal elements, sometimes with immunoblastic morphology, usually scattered throughout the interfollicular areas. By contrast, the expression of HIV p24 was restricted to germinal center cells. All the EBV+ LAS samples were negative for the expression of EBV-encoded latent (LMP-1 and EBNA-2) and replicative proteins (BZLF-1, BHLF-1, EA-D, EA-R and VCA). In addition, amplification of the immunoglobulin heavy-chain genes using 2 different polymerase-chain-reaction protocols showed evidence of B-cell clonal expansion in 2/20 (10%) LAS, one EBV- case, and one sample with low numbers of EBV-infected cells. These results suggest that (i) EBV-carrying cells are probably not involved in the development of LAS, either directly or indirectly; (ii) type-2-EBV-infected cells are present in LAS lymph nodes from the early phases of HIV infection; (iii) EBV-carrying LAS per se probably does not constitute a lesion at high risk for subsequent development of EBV+ lymphomas; (iv) it is unlikely that a high viral load or strong EBV-mediated antigenic stimulation plays a contributory role in the development of EBV-unrelated lymphomas of HIV-seropositive individuals.

AIDS-Related Complex↗
PubMed1995

Structure-activity relationship of verapamil analogs and reversal of multidrug resistance.

We studied the relationship between the chemical structure and multidrug resistance (MDR) reversal activity of racemic verapamil (VER) and 14 VER analogs (VAs). The LoVo-R human colon carcinoma cell line was used as an experimental model. This cell line exhibited a typical MDR phenotype and overexpressed the MDR1 gene products. Key structural features were identified as being related to MDR reversal and cytotoxic activity. In particular, we demonstrated that the methoxy groups in the VER molecule structure [1.7-Bis-(3.4-dimethoxyphenyl)-3-methylaza-7-cyan-8-methyl-n onane] prevented cytotoxicity when the VAs were used alone, whereas the 7-cyan-8-methyl groups were important for MDR reversal activity and interaction with P-glycoprotein (P-gp). Among the VAs tested, the most active compounds were gallopamil, R-isomer of VER (R-VER), and nor-VER, which potentiated doxorubicin (DOX) cytotoxicity by 52.3 +/- 7.2 (n = 3 +/- SD), 38.9 +/- 6.4 (n = 4 +/- SD), and 35.4 +/- 4.3 (n = 3 +/- SD) times, respectively. The reversal activity of these compounds was similar to that of VER, which enhanced DOX cytotoxicity by 41.3 +/- 5.0 (n = 3 +/- SD) times. The potentiation of DOX cytotoxicity was associated with an increase in DOX uptake in LoVo-R cells and with an increased [3H]azidopine P-gp photolabeling inhibition. Some compounds that had a high reversal potency (i.e. R-VER and nor-VER) showed a lower calcium antagonist activity than VER, and seem useful candidates for the treatment of MDR in cancer patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗