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Biomedical subjects

G Rossi

Publications and source records attributed to G Rossi.

At least 181 records · Page 10Linked to original sources
PubMed1999

Yeast homologues of tomosyn and lethal giant larvae function in exocytosis and are associated with the plasma membrane SNARE, Sec9.

We have identified a pair of related yeast proteins, Sro7p and Sro77p, based on their ability to bind to the plasma membrane SNARE (SNARE) protein, Sec9p. These proteins show significant similarity to the Drosophila tumor suppressor, lethal giant larvae and to the neuronal syntaxin-binding protein, tomosyn. SRO7 and SRO77 have redundant functions as loss of both gene products leads to a severe cold-sensitive growth defect that correlates with a severe defect in exocytosis. We show that similar to Sec9, Sro7/77 functions in the docking and fusion of post-Golgi vesicles with the plasma membrane. In contrast to a previous report, we see no defect in actin polarity under conditions where we see a dramatic effect on secretion. This demonstrates that the primary function of Sro7/77, and likely all members of the lethal giant larvae family, is in exocytosis rather than in regulating the actin cytoskeleton. Analysis of the association of Sro7p and Sec9p demonstrates that Sro7p directly interacts with Sec9p both in the cytosol and in the plasma membrane and can associate with Sec9p in the context of a SNAP receptor complex. Genetic analysis suggests that Sro7 and Sec9 function together in a pathway downstream of the Rho3 GTPase. Taken together, our studies suggest that members of the lethal giant larvae/tomosyn/Sro7 family play an important role in polarized exocytosis by regulating SNARE function on the plasma membrane.

Actins↗
PubMed1999

Microsatellite instability in multiple colorectal tumors.

Tumor multiplicity is a hallmark of hereditary cancers: in the colon-rectum multiple tumors represent 5-10% of all colorectal cancer cases. A portion of these cases belongs to hereditary non-polyposis colorectal cancer (HNPCC), a genetic cancer syndrome due to mismatch repair (MMR) gene mutations, phenotypically expressed as microsatellite instability (MSI); the majority of multiple tumors, however, is apparently without any family history. We analyzed 78 (38 synchronous and 40 metachronous) neoplasms from 37 patients with multiple tumors of the large bowel, both HNPCC and sporadic, with the aim of identifying a common genetic basis in multiple tumors. DNA was extracted from normal and cancerous formalin-fixed tissue and was analyzed for MSI using 6 markers. Tumors showing MSI in at least 2 of 6 microsatellite loci were defined as MSI(+). The overall number of MSI(+) tumors was 22 (28.2% of the total). A significant difference in the rate of MSI(+) between HNPCC and sporadic tumors was observed (85% vs. 17%). In the same patients, the MSI phenotype of synchronous tumors (both HNPCC and sporadic) tended to be more concordant than that of the metachronous ones. The higher frequency of MSI in HNPCC than in sporadic tumors, even when multiple, suggests that the involvement of MMR genes in the pathogenesis of the sporadic cases may be uncommon, thus confirming that screening for MSI in multiple colorectal tumors could be a useful tool in the identification of HNPCC in the general population.

Colorectal Neoplasms↗
PubMed1999

Clinical sensitivity to anthracyclines in PH/BCR+ acute lymphoblastic leukemia.

Translocation t(9;22) or Philadelphia chromosome (Ph)/BCR-ABL rearrangement positive acute lymphoblastic leukemia (Ph/BCR+ ALL) is associated with a very short survival of about one year in most patients. We analyzed long-term outcome of 76 adults with Ph/BCR+ ALL, in order to detect which factors were associated with longer survival. Modifiable prognostic factors included type of treatment, allogeneic marrow transplant (allo-BMT), and early anthracycline dose intensity (high = H/A, low = L/A); unmodifiable factors were age, gender, FAB morphology, phenotype, blast count, P190/210 transcript, hepatospleno-lymphadenopathy, LDH level. Median patient age was 43 years (range 15-71). Four favorable prognostic factors (FPF) were found associated with greater likelihood of complete remission (blast count < 50 x 10(9)/l, p = 0.08), longer remission duration (age < 50 years, p < 0.001; H/A, p < 0.05), and lower relapse rate (allo-BMT, p = 0.017). Age and anthracycline dose intensity exerted a synergistic prognostic effect. According to the cumulative incidence of FPF in each patient (FPF 0-1 = 29, 2-3 = 42, 4 = 5), the probability of survival increased from nil to 0.22 to 0.60 at 5 years (p < 0.005). Adult Ph/BCR+ ALL is relatively sensitive to anthracyclines, which therefore should be prescribed at full dosage to patients not eligible to allo-BMT or in the waiting list for unrelated donor transplantation.

Adolescent↗
PubMed1999

The age of patients with thyrotoxicosis factitia in Italy from 1973 to 1996.

Thyrotoxicosis factitia, a syndrome due to the surreptitious ingestion of excess thyroid hormones, has generally been diagnosed in young or middle-aged women with psychopathological disturbances. We reviewed all the cases seen at our Institution over a 24-yr period, from 1973 to 1996. All 25 patients were women. Analysis was restricted to 17 patients who were born and lived in Tuscany (our region), since only these patients were distributed during the whole observation period. Diagnosis of thyrotoxicosis factitia was based on the following parameters: elevated serum total and/or free thyroid hormone levels, undetectable serum thyrotropin levels, low/undetectable serum thyroglobulin concentration, normal urinary iodine excretion, low/suppressed thyroidal radioactive iodine uptake (RAIU), absence of goiter, absence of circulating anti-thyroid antibodies. Surreptitious ingestion of thyroid hormone pill was eventually admitted by all patients. Age at diagnosis was >50 yr in 7/17 patients (41%): 6 of them were distributed in the period 1995-1996, and one in 1988. Patients older than 60 yr were 5/17 (29%), all in the last two years of the period under investigation. There was an increase in the age of patients with thyrotoxicosis factitia (p=0.02), which lost a statistical significance when the patients of the 1995-1996 period were excluded from analysis (p=0.88). This study provides evidence of an increased age of patients with thyrotoxicosis factitia in more recent years. From a practical standpoint, our study suggests that thyrotoxicosis factitia should be suspected and adequately looked for even in old patients with thyrotoxicosis of inexplicable origin, especially in the absence of goiter and thyroid autoimmune phenomena, and when common causes of low-RAIU hyperthyroidism, such as a load with iodine-containing drugs or subacute thyroiditis, have been excluded.

Adolescent↗
PubMed1999

Interethnic and interindividual variabilities of platelet sulfotransferases activity in Italians and Finns.

OBJECTIVE: The aim of this investigation was to see whether there was interethnic variability in the platelet activities of catechol- and phenol sulfotransferases in Italians and Finns. METHODS: The activities of catechol- and phenol sulfotransferases were measured in platelets obtained from 103 Italian and 74 Finnish individuals. Blood donors were obtained from healthy volunteers free from drugs and without apparent disease. The activities of catechol- and phenol sulfotransferases were measured with 60 microM dopamine and 4 microM 4-nitrophenol as substrates, respectively. RESULTS: The activity of catechol sulfotransferase was not gender dependent and the median estimates (pmol/min/mg) were 9.10 in Italians and 6.37 in Finns (P = 0.0018). The activity of phenol sulfotransferase activity was gender dependent in Finns but not in Italians. The median estimates (pmol/min/mg) were 3.81 in Finnish men and 1.18 in Finnish women (P = 0.0007). In Italian men and women, the median estimates (pmol/min/mg) of phenol sulfotransferase activity were 1.25 and 1.24, respectively (NS). CONCLUSION: This study shows that platelet catechol sulfotransferase activity is greater in Italians than Finns and that the activity of phenol sulfotransferase is gender regulated in Finns but not in Italians. Thus, interethnic differences exist in platelet sulfotransferases between Italians and Finns.

Adult↗
PubMed1999

Laparoscopy and laparoscopic ultrasonography for staging pancreatic cancer: critical appraisal.

A pilot study was designed to elucidate the role of staging laparoscopy for determining resectability in patients with pancreatic cancer. The additional value of laparoscopic contact ultrasonography (LCU) was also evaluated with specific regard to its ability to detect hepatic metastases and assess vascular infiltration of the portomesenteric trunk. A consecutive sample of 50 patients referred for operation of a suspected pancreatic cancer were submitted to preoperative contrast-enhanced high-resolution computed tomography (CT) and staging laparoscopy combined with LCU at a university hospital. For those progressing to exploratory laparotomy, the intraoperative findings relating to tumor diffusion and vascular infiltration were compared to CT, laparoscopic, and LCU data. Analytical description of the laparoscopic findings is given. Row data of predicted versus observed vascular infiltration were tabulated for CT and LCU. The sensitivity, specificity, and overall accuracy of each diagnostic test were calculated for comparative analysis. Laparoscopy alone prevented unnecessary laparotomy in 20% of cases. A complete procedure could not be achieved in 28% of patients. Three false-negative staging results occurred. LCU identified small (benign) hepatic nodules not seen by CT in 8% of patients. Sensitivity, specificity, and overall accuracy for assessing vascular infiltration were 82%, 53%, and 69% for CT and 94%, 80%, and 87% for LCU. Laparoscopy was confirmed to be safe and effective for staging pancreatic cancer. Because of its unique capabilities to detect even small peritoneal tumor deposits a quick exploration immediately before laparotomy is advised in all patients. The additional benefit of a more extensive procedure is not supported by our results. Although LCU appears to define the vascular involvement more accurately than conventional CT, the limitation of getting clinically useful ultrasound data in all the patients suggests its adoption in only a selected population.

Adult↗
PubMed1999

A betaPP peptide carboxyl-terminal to Abeta is neurotoxic.

Extracellular Abeta-amyloid and intraneuronal paired helical filaments (PHFs) composed of tau protein are the neuropathological hallmark of Alzheimer's disease. Abeta is a 39- to 43-residue peptide derived by cleavage of a 695- to 770-amino-acid membrane-associate glycoprotein (termed beta-protein precursor, betaPP). Following the observation that an antiserum to an epitope located between residues 713 and 723 of betaPP770 (ie, the transmembrane region of the betaPP distal to Abeta) labels PHFs and that a synthetic peptide homologous to residues 713 to 730 of betaPP770 (betaPP713-730) is highly fibrillogenic and interacts with tau in vitro, it has been hypothesized that betaPP fragments other than Abeta may feature in the pathogenesis of Alzheimer's disease concurring with neuronal degeneration. To investigate this issue, we have analyzed the effects of the exposure of primary neuronal cultures to the synthetic peptide betaPP713-730. Cultures were prepared from rat hippocampus on embryonic day 17 and incubated with the peptide at 2.5 to 30 micromol/L concentration for 1 to 4 days. Cell viability was compared with that of control cultures exposed to a scrambled sequence of the peptide. A 4-day exposure to 20 micromol/L betaPP713-730 resulted in almost complete neuronal loss, whereas no changes were observed with the scrambled peptide. Degenerating neurons showed DNA fragmentation by agarose gel electrophoresis and apoptotic changes by light and electron microscopy. These findings support the view that betaPP sequences other than Abeta may play a role in nerve cell degeneration in Alzheimer's disease.

Amyloid beta-Protein Precursor↗
PubMed1999

Prognostic factors after surgical treatment of lung cancer invading the diaphragm.

BACKGROUND: Diaphragmatic invasion from lung cancer (T3-diaphragm) is a rare occurrence reported to portend a poor prognosis. METHODS: Fifteen patients with T3-diaphragm (14 males, 1 female; median age, 64 years) were surgically treated over a twenty-year period by en bloc resection (14 patients). One patient was only explored. Pathologic stage IIB (T3N0) was found in 11 patients. A partial infiltration of the diaphragm was observed in 3 patients, whereas full-depth invasion was found in 12. Diaphragmatic reconstruction was done primarily in 9 patients, and, by prosthetic material in 5. RESULTS: Two patients are still alive without evidence of disease at 88, and, 114 months from surgery. Overall median survival was 23 months (range, 3 to 168). The actuarial 5-year survival was 20%, when all patients were considered, and, 27%, for T3N0 patients. Univariate analysis showed that prosthetic replacement of the muscle (p = 0.018) was significantly related to survival. CONCLUSIONS: T3-diaphragm is best treated with en bloc resections with wide tumor-free margins and prosthetic replacement of the diaphragm.

Adult↗
PubMed1999

Urokinase-type plasminogen-activator and normal thyroid cell adhesion to the extracellular matrix.

The urokinase-type plasminogen activator receptor (uPA-R) focuses the proteolytic activity of its ligand, the urokinase-type plasminogen activator (uPA), on the cell surface, and can also act as an adhesion receptor for vitronectin (VTN). uPA increases uPA-R affinity for VTN and is also able to cleave its receptor. We have previously shown that uPA-R is involved in the adhesion of normal thyroid cells to VTN. In the present report, we have investigated the effect of uPA on normal thyroid cell adhesion to some extracellular matrix (ECM) components. We show that a short-term treatment with uPA does not change normal thyroid cell adhesion to fibronectin (FNT), collagen (CGN), laminin (LMN) and VTN. The prolongation of uPA treatment increases cell adhesion to VTN, and, less efficiently, to other ECM components. Since the short term uPA treatment causes a partial cleavage of uPA-R, that does not increase with time, the observed increase in cell adhesivity cannot be related to the cleavage of uPA-R. We show that the adhesion improvement after the long term uPA treatment is instead due to a strong increase of the cell-surface expression of the integrin beta3 and a moderate increase of the integrin alpha(v). Both alpha(v) beta3 and alpha(v) beta1 are integrinic receptors for VTN.

Antigens, CD↗
PubMed1999

Expression of integrins of the beta1 family in thyroid cells from patients with Graves' disease in vivo and in vitro.

The expression of the beta1 family of integrins was determined in thyroid follicular cells from patients with Graves' disease (GD). Integrin expression was quantitated by flow fluorocytometry of single cell suspensions with antibodies against the common beta1 chain and the alpha1-alpha6 subunits. Results indicated that also in thyroid glands of GD, as previously observed in nodular goiters, two follicular cell populations with different patterns of beta1 integrin expression coexist (VLAalpha3beta1 and VLAalpha1,3,5,6beta1). The VLAalpha1,3,5,6beta1 thyrocyte population in GD was more abundant than in nodular goiters, ranging from 40 to 70% of the total follicular cells and the overall expression of the beta1 integrins was a two-fold higher. In thyrocytes from patients with GD cultured in vitro, alpha3 and alpha2 expression was regulated by cell-to-cell contact as previously described in normal thyroid cells, while the expression of alpha1, alpha5 and alpha6 was quickly lost during the culture. Our data suggest that the integrin profile of the VLAalpha1,3,5,6beta1 thyrocyte population in GD is induced by micro-environmental conditions rather than being the expression of a constitutive phenotype.

Cells, Cultured↗
PubMed1999

Potential role for excretory-secretory forms of glutathione-S-transferase (GST) in Fasciola hepatica.

The excretory-secretory antigen of Fasciola hepatica (ESA) is involved in the suppressive phenomena of cellular immune responses in rats. The ESA can depress the proliferative response of spleen mononuclear cells and inhibit nitric oxide (NO) production by peritoneal cells. In the present study we identified ESA proteins of ca 24 kDa, which shared significant sequence homology to glutathione-S-transferase (GST) obtained from homogenates of F. hepatica adults, other helminths and different mammals. When the dimeric form of these proteins ca 48 kDa was cultured with rat spleen cells, a significant decrease of proliferative response to Con A was detected, starting from 20 micrograms/ml of ESA protein (P < 0.03). We also observed a significant inhibition of nitrite production by incubation with the dimeric form in normal peritoneal macrophages (P < 0.04). These results indicated that the GST secreted by the parasite could be involved in evasion of the parasite from the host immune response.

Amino Acid Sequence↗
PubMed1999

Hodgkin's disease in 35 patients with HIV infection: an experience with epirubicin, bleomycin, vinblastine and prednisone chemotherapy in combination with antiretroviral therapy and primary use of G-CSF.

BACKGROUND: The optimal therapeutic approach for patients with Hodgkin's disease and human immunodeficiency virus infection (HD-HIV) is unknown. In an attempt to improve the results previously obtained with EBV (epirubicin, bleomycin and vinblastine) without G-CSF (Cancer 1994; 73: 437-44), in January 1993 we started a trial using chemotherapy (CT) consisting of EBV plus prednisone (EBVP), concomitant antiretroviral therapy (zidovudine, AZT or dideoxinosyne, DDI), and G-CSF. PATIENTS AND METHODS: Up to August, 1997, 35 (30 M/5 F) consecutive previously untreated patients (median age 34, range 21-53 years) with HD-HIV were enrolled in the European Intergroup Study HD-HIV. Their median performance status was 1 (range 1-3). At diagnosis of HD, 26% of the patients had AIDS, 90% had B symptoms at HD presentation and 83% had advanced-stage HD. Patients received E 70 mg/m2 i.v. on day 1, B 10 mg/m2 i.v. on day 1, V 6 mg/m2 i.v. on day 1 and P 40 mg/m2 p.o. from day 1 to day 5 (EBVP). Courses were repeated every 21 days for six cycles. AZT (250 mg x 2/day), or DDI (200 or 300 mg x 2/day) if AZT had been previously used, were given orally from the beginning of CT. G-CSF was given at the dose of 5 mcg/kg/day s.c. from day 6 to day 20 in all cycles. RESULTS: An overall response rate of 91% was observed. There were 74% complete responses (CR) and 17% partial responses (PR). Toxicity was moderate, with grade 3-4 leukopenia and thrombocytopenia in 10 (32%) and three (10%) patients, respectively. The median number of administered cycles was 6 (range 3-6). Twenty-three of 35 patients received AZT and nine patients received DDI. Three (8%) patients had opportunistic infections (OI) during or immediately after CT. The median CD4+ cell count was 219/mm3 (6-812) at HD diagnosis and 220/mm3 (2-619) after the end of combined therapy, and these numbers remained unchanged. Ten of 26 (38%) patients who achieved CR relapsed. Twenty-three patients died of HD progression alone or in association with OI, being the cause of death in 48% and 9% of patients respectively. The median survival was 16 months, with a survival rate of 32% and a disease-free survival of 53% at 36 months. CONCLUSIONS: The combined antineoplastic and antiretroviral treatment is feasible, but HD in HIV setting is associated with a more adverse prognosis than in the general population. Although the CR rate obtained was satisfactory, the relapse rate was high. Furthermore, comparison of the results of our two consecutive prospective studies demonstrated no overall improvement in the current trial with respect to the CR rate and survival.

Adult↗
PubMed1999

Induction-consolidation with an idarubicin-containing regimen, unpurged marrow autograft, and post-graft chemotherapy in adult acute lymphoblastic leukaemia.

Between 1991 and 1993 we conducted a collaborative trial in adult acute lymphoblastic leukaemia, introducing an idarubicin (IDA)-containing regimen for induction and early consolidation, and increasing consolidation intensity with an autologous bone marrow transplantation phase (ABMT, patients aged <51 years) followed by further chemotherapy for 12 weeks and low-dose maintenance for 6 months (ABMT patients) or 18 months. 96 patients were evaluable for antileukaemic response after induction with vincristine-prednisone-L-asparaginase plus cumulative IDA 36 or 20 mg/m2 (IVAP-1 and IVAP-2), and for disease-free survival (DFS) after a minimum follow-up >3.5 years with an off-therapy interval >1.5 years. The response rate was 44% (7/16) with IVAP-1 and 90% (72/80) with IVAP-2 (P=0.0001), due to regimen-related toxicities. Post-remission therapy was administered as planned to most cases but protocol violation was registered in some patients eligible to ABMT and post-graft chemotherapy. The 5-year disease-free survival (DFS) rate was 31%. Multivariate analysis indicated that DFS was improved in patients receiving a transplant (11 allogeneic, DFS 70%; 32 ABMT, 36%; 37 neither, 17%; P < 0.001) and was negatively affected by high-risk features such as blast cell count >25x10(9)/l, T-cell or mature B-cell immunophenotype, and t(9;22)/t(4;11) (all P values <0.05). The 5-year DFS rate was 54% for 26 patients with no high-risk factor, 26% for 35 patients with any one, and 6% for 18 patients with any two (P<0.005). IVAP-2 brought about a high complete response rate and post-remission treatment including ABMT was feasible and modestly toxic. In spite of the short post-graft chemotherapy phase, the long-term DFS rate was good in cases with no high-risk feature. However, because autografting may be redundant in the standard-risk category, its role requires further investigation for high-risk cases.

Adolescent↗
PubMed1999

Proviral DNA in the brains of goats infected with caprine arthritis-encephalitis virus.

Archive paraffin wax-embedded sections of brain from goats and kids naturally infected with caprine arthritis-encephalitis virus (CAEV) were examined. Severe leucoencephalitis was present, with infiltration of lymphocytes, plasma cells and macrophages into the white matter, meninges and choroid plexus. On both CAEV-positive and negative (control) tissues, in-situ polymerase chain reactions were used to amplify a DNA sequence specific to the proviral Pol region. In the infected tissues, strong hybridization signals were observed, mainly located in macrophages, microglial cells, astrocytes and oligodendrocytes, and in the ependymal epithelium and choroid plexus. Positive areas were also found in the spinal cord in endothelial cells of small blood vessels. Some neurons showed a positive reaction.

Animals↗
PubMed1999

The Rho GTPase Rho3 has a direct role in exocytosis that is distinct from its role in actin polarity.

Budding yeast grow asymmetrically by the polarized delivery of proteins and lipids to specific sites on the plasma membrane. This requires the coordinated polarization of the actin cytoskeleton and the secretory apparatus. We identified Rho3 on the basis of its genetic interactions with several late-acting secretory genes. Mutational analysis of the Rho3 effector domain reveals three distinct functions in cell polarity: regulation of actin polarity, transport of exocytic vesicles from the mother cell to the bud, and docking and fusion of vesicles with the plasma membrane. We provide evidence that the vesicle delivery function of Rho3 is mediated by the unconventional myosin Myo2 and that the docking and fusion function is mediated by the exocyst component Exo70. These data suggest that Rho3 acts as a key regulator of cell polarity and exocytosis, coordinating several distinct events for delivery of proteins to specific sites on the cell surface.

Actins↗
PubMed1999

Endometrial ability to implant in ectopic sites can be prevented by interleukin-12 in a murine model of endometriosis.

Immune dysfunctions in endometriosis are widely documented but the effectiveness of immunotherapies for the management of the disease is still debated. Progress in this field has also been limited by the lack of an appropriate animal model of the disease. In this study, we created a model of endometriosis in immunocompetent mice to verify the ability of endometrium to implant in ectopic sites and to investigate the potential application of the cytokine interleukin (IL)-12 in preventing this ectopic implantation. Endometriotic lesions were induced in both C57BL/6 and BALB/c mice by inoculating syngenic endometrial fragments through a small laparotomic incision into the peritoneal space. All the animals challenged with syngenic endometrium showed evidence of peritoneal endometriosis at 3 weeks. Histologically, endometriotic lesions consisted of cystic endometrial glands surrounded by a stroma. Intraperitoneal injection of IL-12 was able to reduce total weight and total surface area of endometriotic lesions respectively of 77 and 61% in C57BL/6 and of 42 and 28% in BALB/c mice. These results demonstrate that IL-12 is able to induce a significant prevention of ectopic endometrial implantation in an in-vivo model of endometriosis. These findings support the possibility of using the immune system to generate novel therapies for the management of the disease.

Adjuvants, Immunologic↗
PubMed1999

Identification and characterization of three new alternatively spliced mu-opioid receptor isoforms.

We have identified four new mu-opiod receptor (MOR)-1 exons, indicating that the gene now contains at least nine exons spanning more than 200 kilobases. Replacement of exon 4 by combinations of the new exons yields three new receptors. When expressed in Chinese hamster ovary cells, all three variants displayed high affinity for mu-opioid ligands, but kappa and delta drugs were inactive. However, there were subtle, but significant, differences in the binding profiles of the three variants among themselves and from MOR-1. Immunohistochemically, the major variant, MOR-1C, displayed a regional distribution quite distinct from that of MOR-1. Region-specific processing also was seen at the mRNA level. Antisense mapping revealed that the four new exons were all involved in morphine analgesia. Together with two other variants generated from alternative splicing of exon 4, there are now six distinct MOR-1 receptors.

Alternative Splicing↗