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Biomedical subjects

M Monte

Publications and source records attributed to M Monte.

At least 19 recordsLinked to original sources
PubMed2001

The death substrate Gas2 binds m-calpain and increases susceptibility to p53-dependent apoptosis.

Gas2 is a caspase-3 substrate that plays a role in regulating microfilament and cell shape changes during apoptosis. Here we provide evidence that overexpression of Gas2 efficiently increases cell susceptibility to apoptosis following UV irradiation, etoposide and methyl methanesulfonate treatments, and that these effects are dependent on increased p53 stability and transcription activity. To investigate possible pathways linking Gas2 to p53, a yeast two-hybrid screen swas performed, indicating m-calpain as a strong Gas2- interacting protein. Moreover, we demonstrate that Gas2 physically interacts with m-calpain in vivo and that recombinant Gas2 inhibits calpain-dependent processing of p53. Importantly, the Gas2 dominant-negative form (Gas2171-314) that binds calpain but is unable to inhibit its activity abrogates Gas2's ability to stabilize p53, to enhance p53 transcriptional activity and to induce p53-dependent apoptosis. Finally, we show that Gas2 is able to regulate the levels of p53 independently of Mdm2 status, suggesting that, like calpastatin, it may enhance p53 stability by inhibiting calpain activity.

Animals↗
PubMed2000

Cell-cycle regulation of the p53-inducible gene B99.

B99 is a p53-inducible gene whose accumulation upon p53 activation is restricted to late S/G2 cells. Here we have analyzed B99 regulation during the cell cycle in murine cells with or without functional p53. We report that B99 accumulates in late S/G2 phase, is phosphorylated in mitosis, and disappears in G1 phase, regardless of the status of p53. As a complement to this observation, we show that B99 is not induced by p53 in quiescent cells. Therefore, B99 expression is modulated both by cell-cycle regulatory mechanisms and by p53, and p53 can increase the cellular levels of B99 only during the window of the cell cycle when it is normally expressed. On the basis of these observations we rename B99 Gtse-1 (G-two- and S-phase-expressed).

3T3 Cells↗
PubMed2000

Cloning, chromosome mapping and functional characterization of a human homologue of murine gtse-1 (B99) gene.

Murine Gtse-1 (G(2) and S phase expressed protein), previously named B99, is a wt-p53 inducible gene that encodes a microtubule-localized protein which is able to induce G(2)/M phase accumulation when ectopically expressed. Here we report the cloning and characterization of a new cDNA (GTSE-1) encoding a human homologue of the mouse Gtse-1 protein. Chromosome mapping of mouse and human genes assigned Gtse-1 to chromosome 15 and GTSE-1 to chromosome 22q13.2-q13.3 in a region with conserved synteny to that where Gtse-1 mapped. Analysis of the genomic structure revealed that GTSE-1 contains at least 11 exons and 10 introns, spanning approximately 33kb of genomic DNA. Similar to murine Gtse-1, the product of GTSE-1 localized to the microtubules, was able to delay G(2)/M progression when ectopically expressed and was cell cycle regulated. Taken together, these results indicate GTSE-1 as the human functional homologue of murine Gtse-1.

Amino Acid Sequence↗
PubMed1999

wt p53 dependent expression of a membrane-associated isoform of adenylate kinase.

Six novel p53-inducible transcripts were recently cloned from Val5, a murine cell line stably expressing a temperature-sensitive p53 allele. One of the isolated clones represented a novel isoform of cytosolic adenylate kinase (AK1), a highly conserved monomeric enzyme involved in cellular homeostasis of adenine nucleotides. The corresponding protein, which we named AK1beta, was specifically induced upon activation of wt p53 in Val5 cells. The AK1beta protein differs from cytoplasmic AK1 by having 18 extra amino acids at the N-terminus. The extra residues in AK1beta provide a consensus signal for N-terminal myristoylation; as expected, AK1beta was shown to localize to the plasma membrane. The human AK1 gene contains several consensus p53 binding sites and we report that p53-dependent induction of the alternative AK1beta transcript also occurs in human cells. By using antisense ablation experiments in Val5 fibroblasts we show that AK1beta plays a relevant role in the establishment of reversible cell-cycle arrest as induced by p53 in these cells. These findings suggest that within a p53-dependent genetic program, a specific isoform of adenylate kinase has a previously undescribed growth-regulatory function, which might not necessarily require its best characterized biochemical activity.

3' Untranslated Regions↗
PubMed1998

Population-based case-control study of essential tremor.

Current epidemiologic data on the association between environmental factors and essential tremor (ET) are scanty. In a population-based case-control study we investigated the relationship between some putative risk factors and ET. In the present study, we included all subjects identified during a door-to-door prevalence survey in a Sicilian community, affected by ET, and alive on 1 November 1987 (n=31). Of the 31 prevalent cases of ET, we were able to contact 28 subjects. Twenty-eight controls were randomly selected from the general population and matched to each case for age and sex. Exposure variables were investigated by interviewing the patients and their controls or close relatives, using a structured questionnaire. The odds for habitual alcohol consumption were 0.3, indicating a protective effect. The odds for exposure to agricultural chemicals and domestic animals were 2.5 and 2.7, respectively, suggesting a role as potential risk factors. However, the associations found by us were not statistically significant.

Adult↗
PubMed1997

Hydrogen peroxide is involved in lymphocyte activation mechanisms to induce angiogenesis.

T-lymphocytes from tumour-bearing mice are able to trigger the angiogenic cascade. Since it is known that tumour growth produces reactive oxygen species (ROS), the aim of this study was to evaluate the role of hydrogen peroxide (H2O2) on the activation of lymphocytes and their induction of this vascular response. Studies on lymphocytes, stimulated in vitro by ROS to induce angiogenesis, showed that only the enzyme catalase (CAT) could block the activation. The incubation of normal lymphocytes with H2O2 stimulated these cells to induce angiogenesis. The administration of H2O2 or an oxidative stress-producing drug (doxorubicin) to normal mice activated in vivo angiogenesis. In tumour-bearing mice, high levels of lipid peroxidation products were observed in the spleen, but not in the liver or kidney. Moreover, when the ROS scavenger enzyme activities (superoxide dismutase (SDM) and CAT) were determined, we observed low CAT activity in normal spleens, reflected in a high SDM/CAT ratio, when compared to liver or kidney values. We also showed an increasing value of the SDM/CAT ratio with tumour growth. These results strongly suggest that H2O2 could be involved in the mechanisms of lymphocyte activation and their induction of angiogenesis during tumour growth.

Animals↗
PubMed1996

Endogenous gamma interferon and interleukin-10 in Brucella abortus 2308 infection in mice.

CD-1 mice intravenously infected with the virulent Brucella abortus 2308 strain simultaneously produce significant levels of gamma interferon (IFN-gamma) and interleukin-10 (IL-10) in their spleens between the second and eighth day post-infection with no production of interleukin-4 (IL-4). Endogenous synthesis of IL-10 does not affect the production of IFN-gamma in this organ, while the production of both cytokines during this period of time is accompanied by a statistically significant increase (P < 0.001) in the number of colony forming units (cfu) of B. abortus 2308 present in the organ. These findings suggest that although the endogenous synthesis of IL-10 apparently does not affect IFN-gamma production, it may affect the effector functions of macrophages to control intracellular brucellae. Production of the Th1 cytokine IFN-gamma during B. abortus 2308 infection is also associated with a specific IgG3 and IgG2a response against the B. abortus 2308 lipopolysaccharide (S-LPS) antigen.

Animals↗
PubMed1995

Expression of synapsin I gene in primary cultures of differentiating rat cortical neurons.

Synapsin I is a neuron-specific protein which is present in two isoforms, Ia and Ib. In the last few years this protein has been demonstrated to play a central role in the regulation of neurotransmitter release and synaptic plasticity. In this paper the developmental expression of this protein has been investigated in primary neuronal cultures from fetal rat brain cortices. The presence of thyroid hormone in the culture medium stimulates an early expression of the protein without exerting any effect at the level of mRNA transcription and accumulation. These observations implicate a T3-dependent regulation of this neuron-specific gene at the level of mRNA translation.

Animals↗
PubMed1994

Polyamines prevent DFMO-mediated inhibition of angiogenesis.

Tumor growth mainly depend on formation of new blood vessels. DFMO (alpha-difluoromethylornithine), an inhibitor of polyamine biosynthesis, inhibits tumor growth in many animal tumors. Our investigation was to evaluate the requirement of polyamines for induction of angiogenesis by tumor cells and spleen lymphocytes from tumor-bearing mice. In this regard, we have added DFMO to cell cultures. The neovascular response induced either by tumor cells or spleen lymphocytes was completely abrogated. This inhibition could be reversed by the addition of exogenous putrescine. These findings suggest that the effect of DFMO on angiogenesis is, in part, mediated by the inhibition of polyamine biosynthesis.

Adenocarcinoma↗
PubMed1994

Inhibition of lymphocyte-induced angiogenesis by free radical scavengers.

Solid tumors induce an angiogenic response by the host blood vessels to form a new vascular network for the supply of fresh nutrients and oxygen responsible for tumor growth. Furthermore, tumor growth and metastatic spread is abrogated or markedly reduced in the absence of neovascularization. Spleen T lymphocytes from tumor-bearing mice elicit a strong neovascular response. It is well known that certain T cell responses require the presence of active oxygen radicals. Because these metabolites are produced during tumor growth, we studied whether oxygen free radicals play a role in the angiogenesis induction by lymphocytes. In this study, we demonstrated that the administration of a free radical scavenger (EGb-761) to tumor-bearing mice, blocked the angiogenic response and decreased the lung metastatic incidence. On the other hand, when normal lymphocytes were incubated with the xanthine-xanthine oxidase system (X-XO), a known superoxide anion generator, this elicited a dose-response positive angiogenic reaction in normal recipient mice. No angiogenic response was observed in the absence of X-XO, or when EGb-761 or superoxide dismutase (SOD) plus catalase (CAT) were added to the incubation medium. These results suggest that free radicals are involved in some step of the angiogenic process, and that the EGb-761 treatments block this response due to the free radical scavenging activity of this compound.

Adenocarcinoma↗
PubMed1994

[Free radicals of oxygen and superoxide dismutase. Biological and medical aspects].

Oxygen free radicals (OFR) are very reactive and unstable metabolites capable of altering important biomolecules including proteins, lipids and nucleic acids. OFR are regulated by enzymes such as superoxide dismutases (SOD), catalase, glutation peroxidase and by molecules such as vitamins E, A, C, and K, selenio, cystein and other compounds. Increased OFR levels due to an overproduction of these metabolites or to a failure in the control system, induce cellular and tissue injuries that could lead to diseases such as atherosclerosis, arthritis, fibrosis, lung and heart injuries, neurological disorders and cancer. In this article we consider the use of SOD as therapeutic agents both in human and experimental models. We also refer to the administration of SOD as a protective factor against secondary injuries during radiotherapy and to the determination of SOD as a tumor marker.

Animals↗
PubMed1993

Increase of hemoglobin A2 in human immunodeficiency virus-1-infected patients treated with zidovudine.

We observed increased hemoglobin A2 (HbA2) levels in an asymptomatic human immunodeficiency virus-1 (HIV1) patient with no previous history of beta-thalassemia. He was treated only with zidovudine (AZT). In an attempt to understand this observation, a retrospective study was initiated to determine whether mean HbA2 levels are higher in AZT-treated patients than in subjects not receiving this drug and to assess if other hematologic alterations are associated with elevated HbA2. One hundred fifty-one HIV-positive cases were investigated; AZT was administered to 81 of them. The mean value of HbA2 was 0.032 (SD +/- 0.005) for the treated group vs. 0.027 (SD +/- 0.004) for the controls. This difference was highly significant (P < 0.001). Twenty-four patients (31%) in the treated group had elevated HbA2 levels vs. none in the controls. Bone marrow toxicity seemed to be more significant in patients with heightened HbA2 values, and HbA2 levels did not increase with CDC clinical stage. We conclude that AZT may be linked to high HbA2 levels in some patients.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Immunologic thrombocytopenia followed by thrombotic thrombocytopenic purpura in two HIV1 patients.

Two homosexual HIV1-positive male patients with thrombotic thrombopenic purpura (TTP) were found to have past history of immune thrombocytopenia (ITP). The first patient had ITP 10 months prior to TTP and was successfully treated by splenectomy. The second patient had ITP 32 months before TTP. No specific treatment was given for his asymptomatic ITP. Association of HIV infection to TTP seems to be frequent. These two types of purpura have different pathogenic mechanisms but share a common altered immune response to antigenic challenge. The occurrence of ITP and TTP in HIV-positive patients may lead to errors in diagnosis and therapy.

Adult↗
PubMed1991

Pilot study of sandostatin (octreotide) therapy of refractory HIV-associated diarrhea.

Seventeen AIDS patients were enrolled in a prospective open-label dose-finding study of octreotide (Sandostatin) therapy for refractory diarrhea. Five were nonevaluable due to progression of AIDS symptomatology, and one was excluded because of lack of confirmation of HIV infection. Five of 11 evaluable patients responded to therapy (45%); two each at 50 micrograms and 100 micrograms, and one at 250 micrograms thrice daily doses. A sixth patient demonstrated a moderate reduction in stool volume at 250 micrograms thrice daily, which, although deemed clinically relevant, did not meet the criteria for response. On discontinuation of therapy, diarrhea recurred in all patients within 1-12 days, and responded to reinitiation of octreotide in those five patients who resumed treatment. Only one of the three patients with concurrent cryptosporidial infection responded to treatment. The drug was well tolerated, with mild symptomatology in three patients. Long-term treatment at a stable dose was effective in three of five treated patients for periods for seven months in one (moderate responder) and one year in two. One patient required dose increases to control symptoms, but after one year of treatment developed severe nausea following injections, which required dose cessation. One patient had partial control of his diarrhea for only three months despite two dose increases. These data suggest that octreotide may be of useful therapeutic value in HIV-associated diarrhea and that further studies are indicated.

Adult↗
PubMed1991

Acute and delayed emesis after cisplatin-based regimen: description and prevention.

Lorazepam, dexamethasone and high-dose metoclopramide were given to 54 patients to prevent emesis induced by cisplatin (50-120 mg/m2) on day 1, while prochlorperazine and dexamethasone were administered on days 2 and 3 for control of delayed emesis. Nausea and emesis were recorded from day 1 to day 8. This combination was well tolerated. Prevention on day 1 was complete for 72% of patients and satisfactory (less than or equal to 2 emeses on day 1) in 85%. From days 2 to 8, no emesis, less than or equal to 2 and greater than 2 episodes occurred in 70, 11 and 19%, respectively. Overall control (days 1-8) was complete in 55.5% and satisfactory (less than or equal to 2 emeses on day 1 and/or less than or equal to 2 emeses from days 2 to 8) in 74%. Delayed emesis started on days 2-5. Mean duration was 2.6 days. Delayed nausea or emesis were more frequent when emesis occurred on day 1. Based on data previously reported and on these observations, better ways to prevent delayed events are discussed. Further trials must record systematically delayed side effects.

Acute Disease↗
PubMed1983

[Granulocytic sarcoma of the mediastinum].

The occurrence of a granulocytic sarcoma before any signs of leukemia is unusual and may pose confusing diagnostic problems. This report deals with such a case who presented with a mediastinal thymic tumor and superior vena cava syndrome. The authors emphasize the localization and the histological techniques that are utilized to ascertain the diagnosis.

Adult↗