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G Volpe

Publications and source records attributed to G Volpe.

At least 55 records · Page 3Linked to original sources
PubMed1996

Association of 6q deletions with AIDS-related diffuse large cell lymphoma.

Deletions of chromosome 6 at band q27 represent the site of a putative novel tumor suppressor gene in non-Hodgkin's lymphomas (NHL) of the immunocompetent host. Although several genetic lesions have been identified in AIDS-related NHL (AIDS-NHL), the involvement of 6q27 loss has not been investigated in this NHL category. In this report, we tested the presence of a 6q deletion at the molecular level in a panel of AIDS-NHL representative of the major histologic types, including AIDS-related small non-cleaved cell lymphoma (AIDS-SNCCL; n = 10), AIDS-related diffuse large cell lymphoma (AIDS-DLCL; n = 13) and AIDS-related anaplastic large cell lymphoma (AIDS-ALCL; n = 3). We report that 6q deletions occur in 5/26 AIDS-NHL tested (19.2%). Notably, 6q deletions do not randomly distribute throughout the spectrum of AIDS-NHL histologic types, but rather selectively cluster with AIDS-DLCL (5/13; 38.4%). Overall, these data add to the notion that the molecular pathogenesis of AIDS-NHL is heterogeneous and that distinct genetic pathways associate with specific histologic categories of AIDS-NHL.

Blotting, Southern↗
PubMed1995

Genetic analysis of chromosome 13 deletions in BCR/ABL negative chronic myeloproliferative disorders.

Chromosomal deletions of band 13q14 occur recurrently in BCR/ABL negative chronic myeloproliferative disorders (CMPD), including myelosclerosis with myeloid metaplasia (MMM), polycythemia vera (PV), essential thrombocythemia (ET), juvenile chronic myeloid leukemia (JCML), and the so-called BCR/ABL- chronic myeloid leukemia (CML). The RBI tumor suppressor locus, mapping to 13q14, has long since been hypothesized as the important gene. In this report, we have determined the frequency of 13q14 deletions at the molecular level in a large panel of BCR/ABL- CMPD at different disease stages and performed a detailed genetic analysis of gross rearrangements/deletions and point mutations of the RBI gene in these disorders. Our data show that molecular deletions of 13q14 are detected in a relatively large fraction of BCR/ABL- CMPD (38%), that they appear to be more frequent in MMM than in other BCR/ABL- CMPD, and that they may be present at diagnosis or occur during blastic evolution of the neoplasia. The RBI gene displayed a germline configuration in all BCR/ABL- CMPD tested, suggesting that 13q14 deletions in these disorders affect a tumor suppressor locus distinct from RBI.

Base Sequence↗
PubMed1995

Ciliary neurotrophic factor-induced gene expression in human neuroblastoma cell lines.

We have analyzed the response of the human neuroblastoma cell lines SK-N-SH (clone SY5Y) and SK-N-BE to the ciliary neurotrophic factor CNTF. In both cell lines CNTF induced the expression of the mRNA for two transcription factors, c-fos and NGF1A. The induction was rapid and transient reaching a maximum between 30 and 60 min after exposure to CNTF and subsequently declining. The level of induction of both c-fos and NGF1A mRNAs was much higher in SK-N-BE neuroblastoma cells compared to the SY5Y. Both cells express comparable levels of the transcript for the CNTF receptor-alpha. This mRNA was down regulated after 5 days of CNTF stimulation in both cell lines. CNTF also induced increased levels of the transcript for the growth cone associated protein GAP43 in SK-N-BE, but not in SY5Y cells. Induction followed a slower kinetic compared to that observed for c-fos and NGF1A. In fact, the GAP43 mRNA levels increased during 2 days of exposure to CNTF. Morphological analysis of CNTF treated cells showed that SK-N-BE undergo significant differentiation in response to CNTF (increased number of cells with neurites and increased neurite length) while SY5Y did not show appreciable morphological differentiation. These data shows that CNTF may elicit different response in neuroblastoma cell lines.

Cell Division↗
PubMed1995

Distribution of Kaposi's sarcoma herpesvirus sequences among lymphoid malignancies in Italy and Spain.

In this study we have tested the distribution of Kaposi's sarcoma herpesvirus (KSHV) DNA sequences throughout the spectrum of lymphoid neoplasia in Italy and Spain. 180 cases of lymphoid malignancies representative of the major histologic and immunophenotypic categories of B- and T-cell tumours were analysed by means of a polymerase chain reaction-based assay. KSHV sequences were consistently absent in all categories of lymphoid malignancies studied, with the exception of a subset of B-cell non-Hodgkin's lymphomas localizing in the pleural, pericardial or peritoneal cavities, and fulfilling the diagnostic criteria of body-cavity-based lymphoma. The selective and consistent association of KSHV sequences with cases of body-cavity-based lymphoma throughout the spectrum of lymphoid neoplasms suggests that KSHV may be involved in the pathogenesis of this peculiar type of lymphoid malignancy.

Base Sequence↗
PubMed1995

p53 gene inactivation in acute lymphoblastic leukemia of B cell lineage associates with chromosomal breakpoints at 11q23 and 8q24.

The clinical heterogeneity of acute lymphoblastic leukemia (ALL) of B cell lineage reflects the presence of distinct molecular pathways leading to well-defined ALL molecular subtypes. These molecular pathways include the formation of the fusion transcripts BCR/ABL and E2A/PBX1, due to t(9;22) and t(1;19), respectively, as well as rearrangements of the MLL gene at 11q23 and of c-MYC at 8q24. Hyperdiploid ALL in the absence of chromosomal structural abnormalities is an additional ALL molecular subtype. Mutations of the RAS family genes and of the p53 tumor suppressor gene represent additional genetic lesions detected in a fraction (10-20%) of ALL cases. RAS activation in ALL may be detected in all molecular subtypes of ALL and denotes poor prognosis. Conversely, little is known regarding the clinical and biological features of ALL cases carrying p53 mutations. In order to help clarify the role of p53 inactivation in ALL development, we have determined the frequency of p53 mutations throughout the molecular spectrum of B cell lineage ALL. We report that p53 inactivation in ALL of B cell lineage is restricted to cases carrying a rearrangement of MLL or c-MYC, whereas it is consistently negative in other molecular subgroups. These data underline the molecular heterogeneity of ALL of B cell lineage and indicate that at least some of the molecular pathways involved in ALL pathogenesis require more than one genetic lesion.

Base Sequence↗
PubMed1995

A genetic study of Parkinson's disease.

We performed a case-control study on 100 patients with Parkinson's disease, their spouses and the same number of sex- and age-matched neurological controls to clarify if family history of Parkinson's disease or essential tremor may increase the risk for the disease. We included in the study 68 male and 32 female parkinsonian patients with a mean age +/- SD of 62.0 +/- 9.9 years and a mean disease duration of 7.5 +/- 5.7. The odds ratio for familial Parkinson's disease was 13.4 (95% confidence limits = 6.5-27.7) and for familial essential tremor 3.1 (95% confidence limits = 1.5-6.3). We also reviewed the genetic features of 122 parkinsonian patients with at least one affected relative. The presence of secondary cases among both first-degree (n = 83) and less close relatives (n = 72) suggests that sharing environmental factors does not explain the familial aggregation of the disease. Secondary cases were significantly more frequent in the paternal than in the maternal line (70 vs. 39). The presence of secondary cases among both siblings (46) and parents (37) and the unilateral distribution of ancestral secondary cases suggest an autosomal dominant inheritance with incomplete penetrance.

Adult↗
PubMed1994

Integrin-mediated signal transduction in human endothelial cells: analysis of tyrosine phosphorylation events.

Adhesion of human umbilical endothelial cells to fibronectin resulted in increased tyrosine phosphorylation of a group of proteins with molecular mass ranging from 100 to 130 kDa and of a 70 kDa protein. This pattern of tyrosine phosphorylation was also observed when endothelial cells adhered to vitronectin, collagen IV, collagen I and laminin or to culture dishes coated with antibodies directed to either beta 1, alpha 3, alpha 5, alpha 6 or beta 3 integrin subunits. Increased phosphorylation of the 100-130 kDa proteins was detectable as early as 30 sec after adhesion, reached maximal level after 15 min, and remained high as long as the cells adhere to culture dishes. The 70 kDa protein was phosphorylated with a slower kinetics and its phosphorylation increased over a period of 3 h. Using specific monoclonal antibodies, the major component of the 100-130 kDa complex was identified as the focal adhesion tyrosine kinase p125FAK. The phosphorylation of the p125FAK was also observed by inducing beta 1 integrin clustering in non adherent HEC, indicating that this is a primary signalling event induced by integrins. Using tyrosine kinase inhibitors, we show a direct correlation between integrin-stimulated tyrosine kinases and assembly of focal adhesions and actin fibres.

Antibodies↗
PubMed1990

Endogenous aspartate release in the rat hippocampus is inhibited by M2 'cardiac' muscarinic receptors.

The release of endogenous aspartic acid elicited by depolarization of rat hippocampus synaptosomes with 15 mM KCl was totally calcium-dependent. Acetylcholine (ACh) added to the superfusion medium inhibited the K(+)-evoked release of aspartate in a concentration-dependent manner. The effect of ACh was mimicked by oxotremorine and carbachol. It was insensitive to the nicotinic receptor antagonist mecamylamine but blocked by the non-selective muscarinic receptor antagonist atropine. Further pharmacological characterization of the muscarinic receptor involved showed that the ACh effects was insensitive to the M1 selective muscarinic receptor antagonists pirenzepine and dicyclomine. However, the inhibition by ACh of aspartate release was counteracted by 11-[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H- pyrido-[2-3-b][1,4]benzodiazepine-6-one (AF-DX 116), a selective M2 'cardiac' receptor antagonist. The calcium dependence of the release of aspartate and its regulation through presynaptic receptors are suggestive of a transmitter role for this excitatory amino acid. Moreover, the similarities between the present results and those previously obtained with glutamate are compatible with the idea that aspartate and glutamate are co-released in the rat hippocampus.

Acetylcholine↗
PubMed1990

Ultrasonic diagnosis and perinatal management of complicated and uncomplicated fetal ovarian cysts: a collaborative study.

Ovarian cysts can be demonstrated in the ovaries of fetuses and full term infants at birth. Small cysts involute spontaneously during fetal life or within the first few months of life. Large cysts may cause mechanical complications or respiratory distress. Sonographic detection of fetal ovarian cysts has been reported, as well as intrauterine surgical treatment. The sonographic findings and the outcome of the smaller and the complicated cysts were studied in 25 pregnant women. Uncomplicated fetal ovarian cysts should be monitored by weekly examination until delivery. Huge ovarian cysts may be an indication for cesarean section; or, intrauterine aspiration may be the alternative. Complicated fetal ovarian cysts represent an indication for neonatal surgery.

Female↗
PubMed1990

Conventional B-mode and transvaginal color Doppler in ultrasound assessment of ectopic pregnancy.

The study was arranged in two parts. In the first part, 43 of the clinically suspected ectopic pregnancies were sent for a transvaginal color Doppler examination. Both cystic and complex adnexal masses were carefully scanned for their Doppler flow characteristics. The Pourcelot index (RI) was calculated and the RI 0.40 was used as a cut-off point to differentiate the trophoblastic (RI less than 0.40) and the normal blood flow (RI greater than 0.40). The diagnosis was confirmed by the beta hCG serum test. Three false-negative and one false-positive findings were obtained. The transvaginal color and pulsed Doppler study of the flow within ectopic pregnancy has a high degree of sensitivity (87.5%), specificity (94.7%) and accuracy (90.7%). Pelvic sonograms of another 110 patients with proven ectopic pregnancy were reviewed retrospectively. The ectopic gestational sac with the alive embryo was documented in 11.8% cases and without the embryo in 30.4% cases. A mixed, solid or cystic adnexal mass was detected in 57.8% patients. Intrauterine findings showed a pseudogestational sac in 13.6% cases, a cluster configuration in 18.6% cases and a linear configuration in 67.8% cases. Criteria for the ultrasound diagnosis of ectopic pregnancy influencing its specificity, sensitivity and accuracy are discussed.

Female↗
PubMed1986

[Effects of dihydrostreptomycin and gentamycin on platelet membrane Na+-K+ATPase].

The use of aminoglycosides is characterised by a bound linkage between therapeutic and toxical levels. The aim of our study was to define the influence of diidrostreptomicin and gentamicin over Na+-K+ATPase of membranes of platelets. In this study, Bounting's and Caravaggio's method has been used, while ATPase activity was expressed in n mol of hydrolized ATP/min/mg of proteins. The data so obtained showed that the antibiotics were able to block up ATPase activity.

Adolescent↗
PubMed1984

A-16686, a new antibiotic from Actinoplanes. I. Fermentation, isolation and preliminary physico-chemical characteristics.

Actinoplanes sp. ATCC 33076 is a new strain that was found to produce an antibiotic, designated A-16686, which is a complex of three closely-related polypeptides containing chlorinated phenyl moieties and D-mannose. Both the complex and the single fractions possess a good activity against Gram-positive bacteria. A-16686 specifically inhibits the synthesis of the bacterial cell wall.

Actinomycetales↗
PubMed1982

[Study of T-lymphocyte subpopulations through monoclonal antibodies].

We studied the lymphocyte subpopulations T4+ and T8+ through monoclonal antibodies (McAb). The end of our study was focused in understanding the differences between the values mentioned by the literature and, consequently, determining our range of normality. Thus, we determined the subpopulations T4 and T8 using the antibodies OKT4 IND and OKT8 SUP, which define respectively the subpopulations T helper and T suppressor. Such determinations have been fulfilled whether on the total lymphocytes or on the lymphocytes T purified. Of course, the results obtained are different if we use the total lymphocytes or lymphocytes T purified. This confirms our suspect that the different values mentioned by the literature are determined by the two possible methods: T purified or total lymphocytes. In order to avoid interpretative mistakes, we suggest to express the values of T4+ and T8+ through the relation T4/T8; in fact, studying the single values obtained by the two different methods we proved they are different, but, at the same time, the relation T4/T8 remain unchanged in each method and is included in a "range of normality" from 1,4 to 1,7.

Antibodies, Monoclonal↗