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Biomedical subjects

S Fontana

Publications and source records attributed to S Fontana.

At least 55 records · Page 3Linked to original sources
PubMed1995

An assessment of self-esteem in HIV-positive patients.

The objective of this research is to assess how self-esteem levels differ in HIV-infected subjects in three different risk behaviours: drug addicts, homosexuals, heterosexuals. The sample (n = 104) consisted of: drug addicts (n = 46); homosexual (n = 26); heterosexuals (n = 32). The Rosenberg Self-Esteem Scale (RSES) and the Eysenck Personality Inventory (EPI) were used. A covariance analysis was used to assess the effect of the different personality traits on the 'self-esteem variable' and to eliminate the variance caused by the personality variables. Bonferroni's T-test was used to assess which group contributed to confute the hypothesis of equivalence between the RSES means of the groups. A significant association between the HIV-infection risk behaviour and the level of self-esteem was shown; this association was assessed by eliminating the effect of personality traits. The risk behaviour as well as the personality traits were both indicative of the level of self-esteem. The assessment of each group revealed that the drug addicts had a relatively lower self-esteem level (mean = 35.251) than the homosexuals (mean = 38.698) and the heterosexuals (mean = 38.227). In conclusion the RSES enables clinicians to identify subjects with low levels of self-esteem who need to be psychologically assessed within a vast population of HIV-infected patients.

Adult↗
PubMed1994

A novel strategy of c-myc oncogene in NK activity regulation not related to the W6/32 MHC class-I epitope.

The c-myc gene encodes a nuclear protein whose precise function is still not fully understood. Introduction of a c-myc gene into a number of cell lines leads to an increase in their susceptibility to NK-cell lysis. It was reported earlier that c-myc can induce a decrease in the membrane expression of the MHC class-I molecules and this may be one of the factors that render target cells relatively more susceptible to NK lysis. In this contribution, we show, in a human LCL line transfected with a constitutively active c-myc gene, an increased sensitivity to NK lysis, which correlates with an augmented effector-target binding ability of c-myc-transfected LCLs and with a high ICAM-I expression rather than with down-regulation of MHC class-I W6/32 epitope expression.

Animals↗
PubMed1994

Cloning and characterization of a sulphite-resistance gene of Saccharomyces cerevisiae.

In this paper we describe the cloning and sequencing of the gene (SUL1) responsible for sulphite resistance in a Saccharomyces cerevisiae mutant (Casalone et al., 1992). The deduced amino acid sequence predicted that the gene codes for a zinc-finger protein with five fingers. Comparison of wild-type and mutant gene sequences demonstrated that the mutation event was a transversion from C to G; as a consequence of the mutation a histidine substituted an aspartic acid, affecting directly the fourth finger structure. The SUL1 gene sequence corresponds to that of FZF1 gene (Breitwieser et al., 1993) to which no function was attributed.

Amino Acid Sequence↗
PubMed1994

Treatment and prognosis of centrocytic (mantle cell) lymphoma: a retrospective analysis of twenty-six patients treated in one institution.

We retrospectively attempted to analyse prognostic factors in a group of 26 patients with centrocytic lymphomas (CCL) treated from 1979 to 1991 (representing 7% of all cases of NHL diagnosed in our institution during that period). Ten of the patients were females and 16 males, and their median age at diagnosis was 69 years (range 38-85). The majority of patients (77%) had advanced disease (Ann Arbor stage III-IV) at presentation. Twenty-two patients (85%) had good performance status (0-1 ECOG). B-symptoms were present in 10 cases. Most patients (87%) presented with generalized adenopathies. Bone marrow involvement was observed in 12 patients (46%) and Waldeyer's ring involvement in 5 (4 of them with stage I-II). In 5 cases the liver was involved and 3 pts had gastrointestinal localizations; 15 patients had more than 2 sites of disease: LDH elevation was observed in 8/24 pts. Fourteen patients (54%) received single-agent chlorambucil (3 pts) or CVP (11 pts). Eleven patients were treated with ADM-containing regimens (7 with CHOP or M-ACOD and 4 with 3rd generation regimens). One patient had radiotherapy alone. The complete response (CR) rate was 50% (13/26); 8 patients relapsed with a median time to progression of 19 months, and only 3 responded to salvage treatment. The median overall survival was 33 months, with fewer than 40% of patients surviving longer than 3 years. At univariate analysis the use of ADM-containing regimens seems significantly correlated with the CR rate (p = 0.047), the failure-free survival (p = 0.023), and the overall survival (p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

HLA class II molecules transduce accessory signals affecting the CD3 but not the interleukin-2 activation pathway in T blasts.

MHC class II molecules play a central role in the control of the immune response, but their biologic function and mechanism of action on the surface of activated human T lymphocytes are not entirely understood. In our study, the functional role of HLA class II molecules in T-blast proliferation was investigated by analyzing in parallel the IL-2- and CD3-driven activation pathways. The results indicate that the cross-linking of class II and CD3 molecules significantly increased the CD3-mediated T-blast proliferation, while no effect was observed on the IL-2-driven cell activation. This phenomenon was not confined to either CD4+ or CD8+ subsets nor was specifically affected by CD45 triggering. Biochemical studies showed that signaling via MHC class II molecules in T blasts led to PKC membrane translocation and IP accumulation. The simultaneous triggering of CD3 and HLA class II molecules led to a synergistic effect on IP accumulation but did not increase the CD3-mediated PKC membrane translocation. Our data suggest that HLA class II molecules are involved in T-cell-T-cell interactions and can mediate accessory signals, affecting the T-lymphocyte activation state.

CD3 Complex↗
PubMed1992

[Arterial hypertension and macroangiopathic complications in a group of diabetic out-patients].

We have retrospectively studied 814 diabetic outpatients, 407 hypertensives and 407 normotensives. The aim of the study was to investigate on possible associations between macroangiopathic complications (coronary heart disease, peripheral and cerebral arteriopathy) and well recognized risk factors for atherosclerosis. Macroangiopathy was present in 27% of males and 24% of females (p = NS), and in 32% of hypertensives and 18% of normotensives (p < 0.0001). Macroangiopathy associated, in both sexes, with age and duration of diabetes, but did not correlate, instead, with metabolic control, obesity, serum cholesterol and triglycerides. High triglyceride levels were associated strictly with arterial hypertension, in both sexes, but are more elevated in men. Risk factors for atherosclerosis seem not to be simply considered in the same way in diabetic and non diabetic populations.

Aged↗
PubMed1991

HLA class II molecules on monocytes regulate T cell proliferation through physical interaction in the CD3 activation pathway.

HLA class II molecules are involved in the OKT3-induced T cell activation, since monoclonal antibodies (mAb) to monomorphic determinants of class II antigens are able to inhibit T cell proliferation. This effect involves several of the events leading to T cell activation and proliferation, i.e. interleukin (IL) 1, IL 6 and IL2 secretion and IL2 receptor expression. The main target of the inhibition is represented by monocytes, and the interference of anti-class II mAb in the direct interaction of monocytes with T cells is likely to play a relevant role in the inhibition mechanism. To test this hypothesis, we investigated in the present study the effect of anti-class II mAb on the proliferation of T cells stimulated with mAb OKT3 in the presence of paraformaldehyde-treated monocytes. We show that the inhibition of proliferation is specific and dose dependent, and seems to involve particular class II epitopes. Addition of fixed monocytes to inhibited T cell cultures restores proliferation to a moderate extent, only if monocytes are added within the first 12 h of culture, suggesting that class II antigens or spatially related molecules deliver signals concurrently with the mitogenic stimulus. The blocking capability of anti-class II mAb was not restricted to the CD4+ or the CD8+ T cell subsets, suggesting that, under inhibitory conditions, these mAb affect other structures on the T cell surface, relevant to the monocyte-T cell interaction.

Antibodies, Monoclonal↗
PubMed1991

NK and LAK susceptibility varies inversely with target cell MHC class I antigen expression in a rat epithelial tumour system.

Several cell clones derived from cell lines obtained from a rat thyroid carcinoma, induced by in vivo injection of the Kirsten murine sarcoma virus into thyroid gland, and from its spontaneous lung metastases were analysed for their major histocompatibility complex (MHC) class I antigen expression. The susceptibility to natural killer (NK) cell lysis of these clones, differing in their levels of MHC class I antigen expression, was determined and found to vary inversely with the target cell MHC level, confirming numerous reports of the literature. We then tried to localize the step of the multistage natural cytotoxic process, in which class I antigens could interfere, and tested first whether lymphokine (IL-2) activation of the killer (LAK) cells could overcome the differences in MHC class I expression of target cells. As this did not appear to be the case, we studied the binding step by either a cold target inhibition assay and a target binding assay and found that target cells expressing class I antigens show a lower competitive capacity for effector cells than targets not expressing such antigens, indicating that this interference may occur, at least in our system, in the binding step of the cytotoxic process.

Animals↗
PubMed1990

Inhibition by anti-HLA class II monoclonal antibodies of monoclonal antibody OKT3-induced T cell proliferation. Studies at the mRNA level.

mAb to monomorphic determinants of HLA class II Ag have been shown to inhibit monocyte-dependent OKT3-induced T cell proliferation, indicating that MHC class II molecules play a regulatory role also in Ag nonrestricted, CD3-induced T cell proliferation. This effect involves several steps in the process of T cell activation and proliferation, including IL-1 beta, IL-6, and IL-2 secretion and IL-2R alpha expression. In the present study, we analyzed the effect of an anti-HLA class II mAb (Q5/6) on the mRNA expression of genes related to monocyte and T cell activation. mRNA levels for early (early c-myc, c-fos) and late (late c-myc, N-ras, c-myb) genes involved in T cell activation were determined as well as mRNA levels for IL-1 beta, IL-6, IFN-gamma, IL-2, and IL-2R alpha. The kinetics of mRNA induction for ICAM-1 was also investigated. The results show that in T lymphocytes the expression of c-fos and early c-myc mRNA was unaffected by mAb Q5/6, whereas the c-myb and N-ras mRNA levels were strongly diminished as well as those of IL-2, IL-2R alpha, and IFN-gamma mRNA. An early increase of ICAM-1 mRNA was partially inhibited. In monocytes, a marked reduction of IL-1 beta and IL-6 mRNA was found. It is concluded that the HLA class II determinant involved in the inhibition mechanism can be engaged in the control of IL-1 beta and IL-6 mRNA levels and constitute an accessory signal up-regulating IL-2 and IL-2R alpha gene activation, through a pathway not affecting c-myc and c-fos expression.

Antibodies, Monoclonal↗
PubMed1990

Monoclonal antibody OKT3-induced T cell proliferation: differential role of HLA class II determinants expressed by T cells and monocytes.

Monoclonal antibodies (MAb) to monomorphic determinants of HLA Class II antigens inhibit monocyte-dependent T cell proliferation induced by MAb OKT3 to a different extent, suggesting a differential regulatory role of the corresponding determinants in T cell proliferation. To elucidate the mechanism(s) underlying this pattern, the MAb CR10-343 and Q5/6 with high inhibitory effect and MAb CR11-462 and CR12-356 with low inhibitory effect were characterized. Cross-inhibition studies showed that the four MAb recognize distinct determinants. The determinants recognized by MAb CR10-343 and CR12-462 are spatially close. The determinants recognized by the four MAb appear to be functionally independent in MAb OKT3-induced T cell proliferation, since the inhibitory effect of the combination of MAb CR10-343 and Q5/6 and of the MAb CR11-462 and CR12-356 was additional but not synergistic. To compare the functional activity of HLA Class II determinants expressed by monocytes and by activated T cells in MAb OKT3-induced T cell proliferation, the effect of the four MAb on MAb OKT3-induced T cell proliferation in a monocyte-dependent and in a monocyte-free system was studied. Dose-response and proliferation kinetics studies showed that the four MAb display a similar inhibitory effect on MAb OKT3-induced T cell proliferation in a monocyte-free system. These results suggest fine differences in the role played by monocyte- and T cell-bound HLA Class II determinants in the regulation of MAb OKT3-induced T cell proliferation. This functional heterogeneity may enhance the flexibility of HLA Class II antigens to mediate cell-cell interactions involved in the proliferative response to a variety of mitogenic stimuli.

Antibodies, Monoclonal↗
PubMed1990

[The rhabdomyolytic syndrome: a not uncommon occurrence].

The paper examines one aspect of a medical pathology that is rather unusual and often wrongly diagnosed: rhabdomyolysis (RMC). The series examined suggests that the pathology is relatively common and arises in a wide variety of clinical conditions. In view of the fact that the consequences of rhabdomyolysis may be serious, emphasis is placed on the fact that correct diagnosis may be obtained by the careful consideration of simple clinical parameters such as subjective symptoms, urine colour, urine strip test and serum CPK assays.

Adult↗
PubMed1989

[HBV infection in hospital health workers: study conducted in a Piedmontese hospital].

The screening for hepatitis B virus infection markers of 976 hospital employees pointed out that: the prevalence of subjects who are positive to at least one marker is relatively low (17.52%); the areas with higher rates of prevalence are: the infections diseases division and the radiological area; there is a statistically significant difference as for the positivity of one of the hepatitis B markers among the disaggregated non-medical staff for every single functional area. The data here collected are compared with those collected in other hospitals.

Female↗
PubMed1988

The relationship of modulation of major histocompatibility complex class I antigens to retrovirus transformation in rat cell lines.

The expression of major histocompatibility complex (MHC) Class I antigens has been studied, by means of monoclonal antibodies directed against nonpolymorphic determinants of MHC Class I molecules, in two epithelial differentiated cell lines (FRTL-5 clone 2 and PC clone 3) and in one fibroblast cell line (FRT Fibro) of Fischer rat thyroid origin, before and after infection with various acute retroviruses carrying the v-ras-Ha, v-mos, v-src, polyoma middle T, and c-myc oncogenes. The results obtained indicate that a single virus does not produce identical changes in MHC Class I molecule expression in all tested lines, but a general increase occurs in lines derived from FRTL-5 clone 2 and a decrease occurs in lines derived from PC clone 3 and from FRT Fibro. Thus the modulation of expression seems to proceed always in the same direction in each cell line regardless of the infecting retrovirus and appears to involve posttranscriptional mechanisms, since no modification of expression of mRNA levels has been observed between normal and transformed cells. Only one line of PC clone 3 origin, transformed by the cooperation of two oncogenes (human c-myc and middle T), almost completely lost MHC Class I antigens on the cell surface and presented a significantly reduced synthesis of Class I mRNA.

Animals↗