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S Garcia

Publications and source records attributed to S Garcia.

At least 91 records · Page 5Linked to original sources
PubMed1997

Clinical and pharmacological differences in early- versus late-onset Parkinson's disease.

We evaluated whether patients with early-onset Parkinson's disease (EOPD) have a different clinical profile and pharmacological response than those with late-onset disease (LOPD). We performed a retrospective analysis and an acute pharmacological challenge with L-Dopa in 34 EOPD (age at onset between 21 and 40 years) and 34 LOPD (onset after age 60) patients. All patients completed a structured questionnaire cross-checked against medical record charts and underwent an acute levodopa test. Most significant differences were in the mode of onset, time of diagnosis, and degree of initial improvement. We did not observe differences with regard to motor fluctuations. The acute levodopa test showed no differences in latency to response onset between groups. However, the magnitude of the response was greater and the duration shorter in EOPD patients. Younger patients had greater reductions in bradykinesia scores, whereas posture/gait symptomatology was less responsive in older patients. The type and severity of dyskinesias also differed significantly between groups. Our findings suggest that central pharmacokinetics, pharmacodynamics, and possibly, nondopaminergic systems play a role in the age-related differences observed in Parkinson's disease.

Adult↗
PubMed1997

Purification of ribonucleases Sa, Sa2, and Sa3 after expression in Escherichia coli.

The genes for three small ribonucleases from different strains of Streptomyces aureofaciens have been cloned and expressed in Escherichia coli. The purification of these ribonucleases from the periplasmic space is described. The yields range from 10 to 50 mg of protein per liter of culture medium. The molar absorption coefficients, isoelectric pH values, and pH of optimum activity are reported.

Amino Acid Sequence↗
PubMed1997

Automated and quantitative immunocytochemical assays of CD44v6 in breast carcinomas.

CD44 variants carrying sequences encoded by exon v6 are preferentially expressed in metastatic animal cancer cell lines. CD44v6 overexpression correlates tumor dedifferentiation and progression in some human carcinomas, but the relationship of CD44v6 overexpression with metastatic behavior of tumor observed in animal models is controversial, particularly in breast carcinomas. The discrepancies probably result from analytical bias. We investigated CD44v6 and CD44s expression in 218 frozen samples of primary breast carcinomas. Immunocytochemical procedure was performed under optimal technical conditions using commercially available 2F-10 monoclonal antibody (MAb), a microprocessor-controlled automated device (Ventana Medical Systems, Tucson, AZ), and quantitative evaluation of results by processing digitized-colored microscopic images (SAMBA, Grenoble, France). CD44v6 expression in tissue sections was shown to be independent of the patient age, tumor size, histological types and grades, and the lymph node status. CD44v6 expression was also independent of the expression of molecules endowed with poor prognostic significance detected by MAbs (anti-p53, anti-c-erb B-2 protein, MIB1) on consecutive sections. No significant relationship could be evidenced either between CD44v6 expression, and CD31 involved stromal angiogenesis and cathepsin D. Finally, CD44v6 was independent of markers of hormone dependence (estrogen and progesterone receptors, pS2) and of multidrug resistance (P-glycoprotein). Similar results were observed with anti-CD44s. We conclude that the true prognostic significance of CD44v6 overexpression still remains to be shown under rigorous technical conditions (frozen samples, well-documented MAbs, and optimal standardization of procedure using automation and quantitative analysis) providing data appropriate for further correlation with long-term patient follow-up.

Adult↗
PubMed1997

c-erbB-2 oncoprotein detected by automated quantitative immunocytochemistry in breast carcinomas correlates with patients' overall and disease-free survival.

The prognostic significance of c-erbB-2 oncoprotein overexpression detected in tumours by immunocytochemical assays (ICAs) was investigated in 148 breast carcinomas. ICAs were performed under optimal technical conditions with frozen tissue sections and included automated immunoperoxidase technique and computer-assisted analysis (densitometry) of digitized coloured microscopic images. Results of quantitative ICAs (expressed in percentages of c-erbB-2-positive surfaces and mean optical densities) were correlated with the patients' follow-up in axillary lymph node-positive (N+) and node-negative (N-) subgroups of patients. Patients' follow-up ranged from 9 months (for the first death) to 101 months (for the 121 alive patients) with a 62.5 months mean overall follow-up. It was shown that marked c-erbB-2 immunocytochemical expression in tumours (cut-off point 35%) significantly correlated with the patients' poor overall survival in N+ and in N- patients (Kaplan-Meier, log-rank test, P = 0.045 and P = 0.015). Also, marked c-erbB-2 immunohistochemical expression correlates with short disease-free (P = 0.005), recurrence-free (P = 0.048) and metastasis-free survival (P = 0.05) (Kaplan-Meier, log-rank test) in N+, but not in N- subgroups. It is concluded that in optimal conditions (automated and quantitative ICAs on frozen sections) c-erbB immunohistochemical expression is a significant prognostic indicator in terms of overall and disease-free survival. The c-erbB-2 protein prognostic significance is independent of node status in terms of overall survival, but not of disease-free survival.

Adult↗
PubMed1997

Automated and quantitative immunocytochemical assays of Bcl-2 protein in breast carcinomas.

Expression of the bcl-2 gene was investigated in 218 human breast carcinomas by immunohistochemical analysis. Immunodetections were assessed using (1) frozen sections, (2) documented commercially available monoclonal antibody (bcl-2/124, Dako), (3) automation of immunoperoxidase technique (Ventana) and (4) quantitative evaluation of results by image analysis (SAMBA) and statistical analysis of quantitative data (BMDP software). Bcl-2 protein expression was correlated with current prognostic indicators and with molecular markers detected by the same procedure as for Bcl-2. It was shown that Bcl-2 expression is not related to patients' age, tumour size and type or lymph node status, but an inverse relationship was observed between Bcl-2 and tumour grade (P < 0.0001). An inverse relationship was also observed between Bcl-2 expression and p53 (P < 0.0001), Ki67/MIB1 antigen- (P = 0.0012), and P-gp- (P = 0.002) positive immunoreactions. In contrast, anti-Bcl-2 positive reaction was significantly associated with ER-positive (P < 0.001) and with ER/PR-positive or ER/PR/pS2-positive immunoreactions (P < or = 0.005). Bcl-2 expression was independent of CD31 and cathepsin D expression. Thus, Bcl-2 protein, thought to be antiapoptotic, exhibits parodoxical expression in human breast carcinomas. It is strongly detected in low-grade tumours (well-differentiated) with low (MIB1) growth fraction, but is independent of the tumour progression (size, node status, CD31, and cathepsin D). Bcl-2 acting on apoptosis is related to p53 gene abnormalities in breast carcinomas. Bcl-2 protein expression may also be involved in response to endocrine therapy (associated to ER/PR/pS2 positive immunoreactions) and probably with chemoresistance mechanisms (inverse relationship with P-gp).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Liquid chromatography with ultraviolet absorbance detection of ethylenethiourea in blood serum after microwave irradiation as an auxiliary cleanup step.

The report describes a method of deproteinizing serum that combines the action of acids with microwave irradiation. The acid concentration is ten times smaller than in the usual acid deproteinization method and the results are similar. The main advantages of the proposed method are the maintenance of the pH of the supernatant at around 5, and the reduction of the concentration of the deproteinizing agent. The procedure was applied to the determination of ethylenethiourea in serum samples by HPLC with spectrophotometric detection. Using 0.5 ml of serum, 0.04 microgram of ethylenethiourea were determined with recoveries between 89 and 109%.

Carcinogens↗
PubMed1997

CD31/PECAM automated and quantitative immunocytochemical assays in breast carcinomas: correlation with patient follow-up.

The purpose of this study was to determine the prognostic significance of quantitative CD31 immunohistochemical assays. CD31 assays were performed on a series of 167 breast carcinoma specimens under optimal technical conditions that involved frozen sections, an automated immunoperoxidase technique, and computer-assisted analysis of digitized colored microscopic images. Results of automated quantitative immunohistochemical assays were correlated with patient follow-up (9.6 years). Patients were divided into two subgroups: those who had axillary lymph node-positive (N+) disease and those who had lymph node-negative (N-) disease. The marked immunocytochemical expression of CD31 in tumors (cutoff point, 20%) was significantly (P = .033) associated with a poor overall survival rate (Kaplan-Meier, log rank test); however, a significant association was not observed in the N+ and N- subgroups. CD31-immunostained tumor cell surfaces larger than 20% correlated with the metastasis-free survival rate (P = .004) in all patients and in the N+ subgroup (P = .005) but not in the N- subgroup. In addition, marked immunocytochemical expression of CD31 correlated with the short-term disease-free survival rate (P = .04) in the N+ subgroup but not in the N- subgroup. In multivariate analysis (proportional hazards regression, Cox model) the prognostic significance of CD31 was independent of tumor size and histologic type but not of grade. The results suggest that, under optimal technical conditions (automated and quantitative immunohistochemical assays on frozen sections), immunohistochemical expression of CD31 is a significant prognostic indicator of overall and metastasis-free survival rates. CD31 has limited prognostic value, however, and is not a completely independent prognostic indicator because it is related to nodal status.

Adult↗
PubMed1997

Cathepsin D detected by automated and quantitative immunohistochemistry in breast carcinomas: correlation with overall and disease free survival.

AIM: To determine the prognostic significance and clinical relevance of cathepsin D detected by immunocytochemical assays (ICAs) in breast carcinomas. METHODS: 151 patients presenting with palpable or impalpable breast carcinomas and who had not received any kind of adjuvant chemotherapy or endocrine therapy who were operated from January 1986 to May 1987 were studied. ICAs of tumour specimens were performed in optimal technical conditions (frozen sections, automated immunoperoxidase technique (Ventana), and computer assisted analysis of digitised coloured microscopic images (SAMBA)) to determine cathepsin D immunocytochemical expression. Results of quantitative ICAs were correlated with overall and disease free survival over 8.4 years of follow up in axillary lymph node positive and negative patients. RESULTS: Cathepsin D immunocytochemical expression in tumours of 15% or more was significantly associated with poor overall survival in the whole group and in node positive patients (Kaplan Meier, log rank test p = 0.003 and p = 0.007); however, it was not correlated with survival in node negative patients. Cathepsin D immunocytochemical expression (> 15%) correlated with short disease free (p = 0.015) and short recurrence free survival (p = 0.021) in the group as a whole but not when node positive and negative patients were evaluated separately. CONCLUSIONS: In optimal conditions (automated and quantitative ICAs on frozen sections) cathepsin D immunohistochemical expression is a significant prognostic indicator in terms of overall, disease free, and recurrence free survival; however, there is no correlation when node negative patients are considered separately.

Adult↗
PubMed1997

Production of endometrial matrix metalloproteinases, but not their tissue inhibitors, is modulated by progesterone withdrawal in an in vitro model for menstruation.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are implicated in normal menstruation, but the mechanism of their regulation is not yet clear. Human endometrial stromal cell cultures were established to mimic the events of the late luteal phase of the menstrual cycle: after 6 days of culture with estradiol 17beta (10 nmol/L) and progestin (P, 100 nmol/L), half the cells were subjected to P withdrawal, and medium was harvested on day 10. Decidualization of the cells was verified by PRL immunohistochemistry. Latent MMP-1, -2, -3, and -9 were detected by zymography and quantitated by densitometry, and production of all enzymes was increased on withdrawal of P. This increase was confirmed by enzyme-linked immunosorbent assay for MMP-1. TIMP-1, -2, and -3 also were produced by the cells, with a mean ratio of 3.9:1:1.2, respectively. There was no effect of P withdrawal on either the amount of each TIMP or their relative concentrations. Expression of the messenger RNA for TIMP-1 or TIMP-2 also was not changed by P withdrawal. Thus, withdrawal of P alters the ratio of MMPs to TIMPs in this model in favor of MMPs and, hence, of tissue degradation. However, the focal nature of menstruation-associated MMP activity suggests that P withdrawal is unlikely to be the only factor responsible for in vivo induction of MMPs at menstruation.

Cells, Cultured↗
PubMed1997

Mitogenic actions of endothelin and other growth factors in ovine endometrium.

Endothelin-1 (ET-1) is present in ovine endometrium, primarily in epithelial cells, and increases around the time of implantation. We examined the cell type expressing ET-binding sites in vitro and whether ET-1 has mitogenic actions in the endometrium, alone or in synergy with other growth factors. Purified epithelial and stromal cells were prepared from luteal-phase endometrium. Specific receptors were demonstrated by binding of 125I-ET-1 and proliferative effects of ET-1 and/or other growth factors determined by uptake of [3H]thymidine by cells in serum-free culture. 125I-ET-1 bound to both epithelial (2516 +/- 820 c.p.m./well) and stromal (6368 +/- 1350 c.p.m./well) cells and was displaced by ET-1 (1 mumol l-1). There were no proliferative effects of ET on epithelial cells. ET-1 (10 nmol l-1) stimulated uptake of [3H]thymidine by stromal cells under serum-free conditions in 13/20 individual cell preparations, to 149 +/- 13% of control (untreated = 100%) with dose-dependence between the range of 1 to 100 nmol l-1. Stimulation by fetal calf serum was to 377 +/- 126% of control. The effects on proliferation by other growth factors (dose; % of control +/- S.E.M., number of positive/total number of cell preparations) were: IGF-I (13 nmol l-1; 182 +/- 14, 4/4), epidermal growth factor (EGF; 4.8 nmol l-1; 132 +/- 5%, 7/7), platelet-derived growth factor-BB (0.4 nmol l-1; 146 +/- 3, 2/2) and leukaemia inhibitory factor (0.4 nmol 1-1; 110 +/- 2, 3/3). All stimulations except that of EGF were significant and dose-responsive but only insulin was additive with ET (350 +/- 35, 5/5). ET-1 also stimulated expression of the the AP-1 cis element c-jun, this being maximal at 60 min of exposure to mitogen. ET-1, along with other growth factors has a likely paracrine role in cellular proliferation in the endometrium, possibly in association with blastocyst implantation.

Animals↗
PubMed1997

Morphometry and densitometry of alveolar macrophage cytoplasmic particles in Chernobyl, Ukraine, liquidators.

OBJECTIVE: To characterize intracytoplasmic particles found in alveolar macrophages (AMs) sampled by bronchial alveolar lavage (BAL) performed on Chernobyl, Ukraine, liquidators suffering form chronic obstructive lung disease. STUDY DESIGN: Eight BALs were assessed. BAL products containing AMs were cytocentrifuged, and appropriate fixation and epoxy embedding were performed for ultrastructural study. Morphometry of cells (AMs) and of cytoplasmic particles was then obtained by processing, using dedicated software, digitized ultrastructural images. RESULTS: AM cytoplasm contained crowded phagolysozomes, varying in size, shape and density and enclosing dense particles rich in radionuclides, with particular morphometric features: surface, 387 +/- 543 pixels (mean +/- SD); number, 77 +/- 34; phagozome/cell surface ratio, 23.7%; shape factor, 1.32 +/- 0.23; and mean optical density, 171 +/- 31. CONCLUSION: Processing of digitized ultrastructural images of AMs provides accurate morphometric data that can be used further for clinical purposes, in particular to evaluate BAL performed either for diagnosis or treatment.

Adult↗
PubMed1997

[Outcome of nephrogenic metaplasia of the bladder in kidney transplant recipients].

OBJECTIVES: To evaluate the risk of recurrence and malignant degeneration of vesical nephrogenic metaplasia in renal transplant recipients. MATERIAL AND METHODS: Fourteen patients with known nephrogenic metaplasia were systematically followed. Vesical biopsies were performed with a resector, stained with eosin haemalun saffron, analysed and compared to initial results. Labelling by anti-EBV and anti-CMV monoclonal antibodies was performed in 5 cases of intense inflammatory reactions. RESULTS: All patients were males, with a median age of 39 years. Nephrogenic metaplasia had been diagnosed 7 to 80 months after renal transplantation (median = 37.8). Twelve patients were reviewed 5 to 116 months after the initial diagnosis (median = 52). Relapse was observed in 83% of cases, but without any malignant degeneration. CONCLUSION: Nephrogenic metaplasia is therefore a benign recurrent disease. The importance of the initial blood supply and fibrosis in the case of recurrence suggest a disorder of the blood supply, probably traumatic in origin. Only symptomatic patients are currently followed.

Adolescent↗
PubMed1996

Dual character, asynaptic and synaptic, of the dopamine innervation in adult rat neostriatum: a quantitative autoradiographic and immunocytochemical analysis.

Dopamine (DA) axon terminals (varicosities) in the neostriatum of adult rats were examined for shape, size, content, synaptic incidence, type of junction, synaptic targets, and microenvironment after electron microscopic identification either by [3H]DA uptake autoradiography or by immunocytochemistry with monoclonal antibodies against DA-glutaraldehyde-protein conjugate. Both approaches yielded comparable results. Whether they were from the paraventricular or the mediodorsal neostriatum, respectively, the [3H]DA-labeled and DA-immunostained varicosities were generally oblong and relatively small; more than 60% contained one or more mitochondria. Sixty to seventy percent were asynaptic, and 30-40% were endowed with a synaptic membrane differentiation (junctional complex), as inferred by stereological extrapolation from single thin sections (both approaches) or observed directly in long, uninterrupted series of thin sections (immunocytochemistry). The synaptic DA varicosities always displayed symmetrical junctions: 67% with dendritic branches, 30% with dendritic spines, and 2-3% with neuronal cell bodies. DA varicosities juxtaposed to one another were frequent. Other axonal varicosities were more numerous in the immediate vicinity of DA varicosities than around randomly selected, unlabeled terminals. The respective microenvironments of DA and unlabeled varicosities also showed enrichment in the preferred synaptic targets of both groups of varicosities, with dendritic branches for DA and dendritic spines for the unlabeled ones. These data suggest a dual mode of operation that is diffuse as well as synaptic for the nigrostriatal DA system. In such a densely DA-innervated brain region, they also lead to the hypothesis that a basal level of extracellular DA might be maintained permanently around every tissue constituent and, thus, contribute to the mechanisms of action, properties, and functions (or dysfunctions) of DA within the neostriatum itself and as part of the basal ganglia circuitry.

Animals↗
PubMed1996

Dual function of a human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte clone: inhibition of HIV replication by noncytolytic mechanisms and lysis of HIV-infected CD4+ cells.

CD8+ T cells may play a beneficial role in human immunodeficiency virus (HIV)-infected patients by two mechanisms. HIV-specific cytotoxic activity and secretion of a soluble mediator(s) that inhibits HIV replication in vitro. Here we characterized both activities mediated by an HIV p24gag-specific cytotoxic T lymphocyte (CTL) CD8+ clone derived from an HIV-infected patient. When the CTL clone was mixed with HIV-infected autologous CD4+ T cells, viral replication was suppressed. This viral inhibition was observed in heterologous CD4+ T cells and when CD8+ and CD4+ populations were separated by a semipermeable membrane, demonstrating the involvement of a diffusible factor(s). The lysis of autologous HIV-infected T cells was also detected. However, HIV suppression was more efficient when CD4+ and CD8+ T cells shared major histocompatibility complex alleles and were in direct contact. Thus, one and the same CD8+ T cell population can mediate both lysis of HIV-infected targets and nonlytic suppression of HIV replication. These results underline the multiple roles of CD8+ T lymphocytes in the suppression of HIV-infected cells.

Amino Acid Sequence↗
PubMed1996

Evidence for an in vivo superantigenic activity in human immunodeficiency virus-infected individuals.

In a previous study, we reported the existence of a specific anergy affecting selectively the V beta 8 subset in both CD4 and CD8 T cells from human immunodeficiency virus (HIV)-infected persons. Because this observation gives evidence for a previous in vivo activation of this subset by a superantigen, we further characterize, in the present study, this V beta 8-anergy associated with HIV infection. Molecular T cell receptor analysis indicates that the V beta 8-anergized T cells are polyclonal. Furthermore, we show the dependence of this anergy on the expression of allelic forms of HLA class II DRB1 molecules. These observations explain the frequency of anergic persons among HIV-infected donors (56%) and are consistent with a previous in vivo superantigenic activity. Comparative analyses of disease evolution between V beta 8 responder and anergic persons do not show any clear relation between the V beta 8 status and acquired immunodeficiency syndrome pathogenesis. However, the stability of the V beta 8 status, the absence of correlation with previous microbial infections, and the previously reported precocity of V beta 8 anergization are in favor of a strong association between the in vivo existence of a V beta 8-specific superantigen and HIV infection. Finally, the functional dichotomy we observe for all anergized donors between blood and lymph node T cells raises the question of the in vivo localization of the superantigenic activity.

Alleles↗
PubMed1996

A western surgical experience of peripheral cholangiocarcinoma.

The aim of this retrospective study was to analyse outcome in 31 European patients operated on for peripheral cholangiocarcinoma between 1988 and 1995 (hilar cholangiocarcinoma was excluded). Before 1992, in addition to conventional resection, patients with irresectable tumour and with no extrahepatic metastasis underwent total hepatectomy with liver transplantation. Mild abdominal pain was the most frequent presenting clinical sign (11 of 31 patients) and jaundice was present in only four patients. Preoperative histological findings were available for 20 patients but the diagnosis was correct in only eight of these. Nineteen patients had curative surgery: 17 underwent conventional resection and two had total hepatectomy with liver transplantation. Major hepatectomy was performed in 12 of 17 cases, extended to the caudate lobe in five, to the bile duct confluence in four and to the retrohepatic vena cava in one. Postoperative mortality and morbidity rates were three and seven of 19 patients respectively, median survival was 15 months, and actuarial 1-, 2- and 5-year survival rates were 67, 40 and 32 per cent respectively. Twelve patients had only exploratory laparotomy because of the presence of extrahepatic metastasis or irresectable tumour. The invasive nature of peripheral cholangiocarcinoma can explain the limited number of resectable cases and the particularly unfavourable prognosis. Total hepatectomy does not provide survival benefit. Conventional surgery remains the only effective treatment, even for patients with advanced stage tumours.

Adult↗
PubMed1996

Ultrastructural characterization of the acetylcholine innervation in adult rat neostriatum.

The ultrastructural features of acetylcholine axon terminals (varicosities) in adult rat neostriatum were characterized by electron microscopy after immunostaining with a sensitive monoclonal antibody against rat choline acetyltransferase. Several hundred single sections from these varicosities were analysed for shape, size and content, presence of a synaptic membrane specialization, and composition of the microenvironment. An equivalent number of unlabeled varicosities selected at random from the same micrographs were similarly examined. The immunostained varicosity profiles were relatively small and seldom showed a junctional membrane specialization. Stereological extrapolation to the whole volume of these varicosities indicated that less than 10% were synaptic. Far fewer dendritic spines were juxtaposed to these predominantly asynaptic profiles than to their unlabeled counterparts. This difference seemed imputable to the low synaptic incidence of the acetylcholine varicosities and was consistent with the view that these are randomly distributed in relation to surrounding elements. The bulk of the data was suggestive of volume transmission. This raised the possibility that, in such a densely innervated area, a basal level of acetylcholine is permanently maintained around all cellular elements, contributing to the modulatory properties of this transmitter. This basal level of acetylcholine could also serve as a regulatory signal controlling the expression of different receptor subtypes in neurons, glia and blood vessels.

Acetylcholine↗