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L M Garcia

Publications and source records attributed to L M Garcia.

7 recordsLinked to original sources
PubMed2006

Fitting the linear-quadratic model to detailed data sets for different dose ranges.

Survival curve behaviour and degree of correspondence between the linear-quadratic (LQ) model and experimental data in an extensive dose range for high dose rates were analysed. Detailed clonogenic assays with irradiation given in 0.5 Gy increments and a total dose range varying from 10.5 to 16 Gy were performed. The cell lines investigated were: CHOAA8 (Chinese hamster fibroblast cells), U373MG (human glioblastoma cells), CP3 and DU145 (human prostate carcinoma cell lines). The analyses were based on chi2-statistics and Monte Carlo simulation of the experiments. A decline of LQ fit quality at very low doses (<2 Gy) is observed. This result can be explained by the hypersensitive effect observed in CHOAA8, U373MG and DU145 data and an adaptive-type response in the CP3 cell line. A clear improvement of the fit is discerned by removing the low dose data points. The fit worsening at high doses also shows that LQ cannot explain this region. This shows that the LQ model fits better the middle dose region of the survival curve. The analysis conducted in our study reveals a dose dependency of the LQ fit in different cell lines.

Animals↗
PubMed2001

Lipopolysaccharide internalization activates endotoxin-dependent signal transduction in cardiomyocytes.

We tested the hypothesis that bacterial lipopolysaccharide (LPS) must be internalized to facilitate endotoxin-dependent signal activation in cardiac myocytes. Fluorescently labeled LPS was used to treat primary cardiomyocyte cultures, perfused heart preparations, and the RAW264.7 macrophage cell line. Using confocal microscopy and spectrofluorometry, we found that LPS was rapidly internalized in cardiomyocyte cultures and Langendorff-perfused hearts. Although LPS uptake was also observed in macrophages, only a fraction of these cells were found to internalize endotoxin to the extent seen in cardiomyocytes. Colocalization experiments with organelle or structure-specific fluorophores showed that LPS was concentrated in the Golgi apparatus, lysosomes, and sarcomeres. Similar intracellular localization was demonstrated in cardiomyocytes by transmission electron microscopy using gold-labeled LPS. The internalization of LPS was dependent on endosomal trafficking, because an inhibitor of microfilament reorganization prevented uptake in both cardiomyocytes and whole hearts. Inhibition of endocytosis specifically restricted early activation of extracellular signal-regulated kinase proteins and nuclear factor-kappaB as well as later tumor necrosis factor-alpha production and inducible nitric oxide synthase expression. In conclusion, we have demonstrated that bacterial endotoxin is internalized and transported to specific intracellular sites in heart cells and that these events are obligatory for activation of LPS-dependent signal transduction.

Animals↗
PubMed2001

Use of stents for small coronary arteries. Results of the Multi-Link 2.5 Portuguese Registry.

INTRODUCTION: Stents are being used with increasing frequency in percutaneous transluminal coronary angioplasty (PTCA) but their use in small vessels is still controversial, due to the possibility of excessively high rates of adverse events and restenosis. OBJECTIVE: To assess the safety and clinical efficacy of ACS RX Multi-Link (ML) 2.5 mm stents, in "de novo" coronary stenosis. DESIGN: Prospective Registry, with 6 months clinical follow-up, involving all Portuguese centers of Interventional Cardiology. POPULATION: Between April 7 and November 20 1998, 102 patients were enrolled, 82 male and with ages ranging from 30 to 86 years (average 58 +/- 11). Clinical presentation for PTCA was stable angina in 53%, unstable angina in 36% and silent ischemia in 11%. There was a history of previous myocardial infarction in 29% of patients. The main risk factors were hypertension (58%), hyperlipidemia (57%), smoking (25%) and diabetes (20%). Multivessel coronary artery disease was present in 46% of patients and left ventricular function was normal in 89%. Of the 217 existing lesions, 188 (87%) were treated: 35 with balloon angioplasty and 153 with stent implantation, 114 of which were ML 2.5 mm: 79 of 15 mm in length and 35 of 25 mm. METHODS: Angiographic success with ML stent implantation and major adverse cardiac events (MACE)--myocardial infarction (MI), coronary artery bypass graft (CABG), new target vessel revascularizations and death--were evaluated during hospital stay, and at 1 and 6 months clinical follow-up. RESULTS: Angiographic success was 97.4%. In one patient it was not possible to cross the lesion, in another there was stent migration and in a third distal coronary flow after stenting was TIMI grade 1. Clinical success was 96.1% and there were no cases of death, Q-wave MI or urgent CABG. Two patients had non-Q wave MI and two required urgent repeat angioplasty. Subacute stent thrombosis occurred in 1 patient. There were no additional MACE at 1 month follow-up. At 6-month follow-up (in 97% of patients) MACE had occurred in 14.1%: 2 deaths (one non-cardiac), 3 MI (one non-Q) and 14 new PTCA (one in a non-ML stent). There was no need for CABG in any patient. Six-month survival rate was 97.9%, 94.9% were free of infarction and 84.8% were free of infarction and new revascularization. CONCLUSIONS: Multi-Link 2.5 mm stent implantation appears to be safe and efficient with a low incidence of immediate and 6-month adverse events in the range of centers and operators of the Registry.

Adult↗
PubMed1999

The impact of insurance status on drug abuse treatment completion.

This article discusses the impact of insurance status on drug abuse treatment completion in a not-for-profit organization, presents demographic findings, mentions financial obstacles to paying for treatment, and describes the relationship between different variables: treatment modalities versus type of drug, treatment modality versus length of stay, reason for discharge versus type of drug, and reason of discharge versus treatment status (completed/not completed). Baseline data (n = 6,539) for the period 1990-1997 was analyzed. For the insurance status analysis we randomly selected and analyzed 1,153 client entries. A statistical software package (STATA) was used for a combination of bivariate and multivariate analysis. Our results indicated, consistent with expectations, that lack of health insurance is associated significantly with not completing treatment. Therefore, new strategies and mechanisms of payment should be created to overcome these obstacles and facilitate treatment completion for clients without insurance coverage.

Ambulatory Care↗
PubMed1998

Neuropharmacological activity of Solanum nigrum fruit.

The ethanol extract of the fruit of Solanum nigrum L. (Solanaceae) was studied for its neuropharmacological properties on experimental animals. On intraperitoneal injection, the extract significantly prolonged pentobarbital-induced sleeping time, produced alteration in the general behavior pattern, reduced exploratory behavior pattern, suppressed the aggressive behavior, affected locomotor activity and reduced spontaneous motility. The observations suggest that the fruit of S. nigrum possesses potential CNS-depressant action.

Animals↗