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Biomedical subjects

A Suarez

Publications and source records attributed to A Suarez.

At least 37 records · Page 2Linked to original sources
PubMed1998

Induction of virus-induced IDDM in virus resistant mice without lymphocyte maturation.

The role of lymphocytes in the pathogenesis of viral-induced insulin dependent diabetes mellitus (IDDM) is controversial. To better understand how a virus-induced IDDM depends on the infiltrating lymphocytes, encephalomyocarditis virus (EMCV) was inoculated intraperitoneally into three kinds of mice; virus-susceptible C57BL/6, virus-resistant 129/SV and recombination activity gene-2 (Rag2) knockout 129/SV mice. Pancreatic inflammation and beta cell necrosis were evaluated after EMCV, D variant (10(3) pfu/mouse) inoculation. On post-inoculation day 14, the lethal rates of C57BL/6, 129/SV and Rag2 knockout mice were 52, 10 and 100%, respectively. The blood glucose in Rag2KO mice on day 8 was significantly elevated as compared with 129SV mice (231 +/- 49 vs 169 +/- 32 mg/dl, P<0.05). In situ hybridization demonstrated the EMCV genome in the pancreas of Rag2 knockout and C57BL/6 mice, but not in 129/SV mice. Beta cell necrosis were more severe in Rag-2 knockout mice than in wild type 129/SV mice, but lymphocyte infiltration was less severe than C57BL/6. Pancreas in Rag2 knockout mice infected with virus were affected more severely than the virus-resistant strain of mice. Diabetogenic virus induced IDDM in virus-resistant mice without mature lymphocytes.

Animals↗
PubMed1998

Genetics of hybridization between Drosophila simulans females and D. melanogaster males.

Drosophila simulans and D. melanogaster are sibling cosmopolitan species with imperfect ethological isolation. Hybridization is easy between D. melanogaster females and D. simulans males, but the reciprocal cross has been traditionally considered as very scarce and little is known about the environmental and genetic factors that affect it. We used classical genetic analyses to determine the influence of each major chromosome on the breakdown of sexual isolation between females of D. simulans and D. melanogaster males. In addition, we have made a first attempt to locate the genetic systems involved in this process. At least two genes, or two groups of genes, are responsible for hybridization, located in the X chromosome and in the left arm of chromosome II. The inheritance mode of both genetic systems is different. The genes in the X chromosome show dominance for high levels of hybridization, whereas those in chromosome II show dominance for low levels. These results contrast with other investigations on the melanogaster subgroup, suggesting independent evolutionary events events during the speciation process in each species.

Animals↗
PubMed1998

Outpatient utilization patterns of integrated and split psychotherapy and pharmacotherapy for depression.

OBJECTIVE: This exploratory study examined utilization and costs among depressed patients in two treatment models-integrated treatment, in which psychotherapy and pharmacotherapy were provided by a psychiatrist, and split treatment, in which pharmacotherapy was provided by a psychiatrist and psychotherapy by a nonphysician psychotherapist. METHODS: A quasi-experimental retrospective design was used to compare claims data from a national managed mental health care organization for 191 patients in integrated treatment and 1,326 in split treatment. RESULTS: During the 18-month study, patients receiving integrated treatment used significantly fewer outpatient sessions and had significantly lower treatment costs, on average, than those in split treatment. Integrated treatment appeared to be associated with a pattern of utilization characterized by frequent treatment episodes in contrast to that of split treatment, which was characterized by more sessions with fewer breaks of 90 days or more. CONCLUSIONS: The results do not support the prevailing assumption that integrated treatment is more costly than split treatment in a managed care network. Despite limitations in the study methods, the strength of these preliminary findings poses a powerful challenge and invites further study.

Adolescent↗
PubMed1998

Effects of an asthma management program on the asthmatic member: patient-centered results of a 2-year study in a managed care organization.

OBJECTIVE: To report the results of a 2-year pilot program of asthma education based on National Heart, Lung, and Blood Institute treatment guidelines. PATIENTS AND METHODS: Asthmatic members (n = 6698) of a managed care organization received education about their condition directly or through their primary care physician. Medical and pharmacy administrative claims data were reviewed to measure acute asthma events and prescribed therapies in the first (the baseline) and second years of the study. The claims data were augmented by member surveys from a stratified random sample of 2734 asthmatic patients who were members (6 years of age or older) in the baseline year. RESULTS: Compared with the first year, asthmatic members received fewer inpatient services and the proportion of asthmatic members prescribed oral inhaled corticosteroids increased 30% in the second year. Health-related quality of life, measured with validated general and disease-specific instruments; satisfaction with the quality of care; exposure to patient education; knowledge of the disease; and member's confidence in their ability to manage their disease showed statistically significant improvements during the follow-up year of the program for both adult and child asthmatic members. CONCLUSION: For asthmatic members of this health plan, a comprehensive asthma health management program improved processes of care and outcomes.

Adolescent↗
PubMed1997

Green fluorescent protein-based reporter systems for genetic analysis of bacteria including monocopy applications.

The green fluorescent protein (GFP) gene, gfp, was used to develop versatile reporter systems for genetic analysis in, and monitoring of bacteria. This reporter system is available on a plasmid and on a mini-transposon located in a suicide delivery plasmid for generation of chromosomal fusions. To achieve sensitivity levels necessary for use in monocopy applications and for detection of single cells, the 3'-end of gfp was replaced by that of a modified gfp gene characterized by a 45-fold stronger fluorescence signal than that exhibited by the natural GFP. This modified gfp gene was also equipped with the strong translation signals of the atpE gene. Transfer of the mini-transposon into two different Pseudomonas spp. and Alcaligenes eutrophus produced random chromosomal fusions, some 5% of which exhibited fluorescence detectable by eye. Individual GFP+ cells were readily observed by fluorescence microscopy.

Bacteria↗
PubMed1997

Gliclazide treatment of streptozotocin diabetic rats restores GLUT4 protein content and basal glucose uptake in skeletal muscle.

This study examined whether the treatment of streptozotocin (STZ)-diabetic rats with gliclazide (5 mg/kg body weight twice daily orally) increases muscle glucose uptake. Rats were treated (group G, n = 10) or untreated (group D, n = 11) for 12 days. Normal rats served as controls (group C, n = 11). At the end of the treatment, both basal and insulin-stimulated glucose uptake by the perfused hindquarters were measured. In gastrocnemious muscles, the protein content of GLUT4 and the insulin binding and tyrosine kinase activity of partially purified solubilized insulin receptors were measured. Group G had a lower mean glycemic value during the treatment period than group D (mean +/- SEM, 17 +/- 0.6 v 19.7 +/- 0.5 mmol/L, P < .05), without differences in serum insulin levels. Basal glucose uptake by the hindquarters was significantly higher in group G versus group D (2.8 +/- 0.3 v 1.3 +/- 0.2 mumol/g/h, P < .05), and was not different versus group C (3.6 +/- 0.2 mumol/g/h). Insulin-stimulated glucose uptake was higher (P < .05) in group C compared with the two groups of diabetic rats. Glucose uptake at 10(-7) mol/L insulin was higher in group G than in group D (9.2 +/- 0.6 v 7.0 +/- 0.6 mumol/g/h, P < .05). Both insulin binding and tyrosine kinase activity were similar in muscle insulin receptors from both groups of diabetic rats. The GLUT4 protein content was higher in group G than in group D (95 +/- 10 v 57 +/- 7 arbitrary units [AU]/microgram protein, P < .05) and similar to that of group C (113 +/- 13 AU/microgram protein). In conclusion, gliclazide has a glucose-lowering effect in STZ-diabetic rats that could be attributed to an increase in muscle glucose clearance by a post-insulin receptor mechanism, probably related to a normalization of GLUT4 content.

Animals↗
PubMed1997

Total volume paracentesis decreases variceal pressure, size, and variceal wall tension in cirrhotic patients.

It has been suggested that ascites is a risk factor for variceal bleeding in cirrhotic patients. However, no data of total volume paracentesis (TVP) effects on variceal hemodynamics has yet been published. The aim of this study was to investigate the effects of TVP on variceal pressure, size, and tension in cirrhotic patients. Before sclerotherapy, 18 cirrhotic patients with grade II esophageal varices were studied. The following measurements were performed on 12 patients at basal condition and after TVP: inferior vena cava pressure, esophageal pressure (EP), and intravariceal pressure (IVP) by direct punction and variceal size at endoscopy. The same measurements were performed at basal condition and 1 hour later without TVP on the other 6 patients used as a control group. Variceal pressure gradient (VPG) and variceal wall tension (WT) were calculated. Paracentesis and intra-abdominal pressure were obtained with a direct punction. No demographic differences were observed between both groups. Paracentesis produced a significant reduction of IVP (from 25.6 +/- 2.4 to 17.9 +/- 2.1 mm Hg, means +/- SEM, -30%, P < .05), VPG (from 16.6 +/- 2.4 to 10.8 +/- 1.4 mm Hg, -35%, P < .05). TVP also reduced variceal size (from 9 +/- 0.3 to 5.6 + 0.4 mm, -38%, P < .05) and WT (from 75.3 +/- 11.6 to 30 +/- 4.7 mm Hg. mm, -60%, P < .05). Intra-abdominal pressure decreased from 18 +/- 2.2 to 4 +/- 0.9 mm Hg (P < .05), and IVC decreased from 15.5 +/- 2.4 to 5.7 +/- 1.5 mm Hg (P < .05). No significant differences were observed in mean arterial pressure and heart rate. The mean ascitic fluid removed was 8 +/- 0.71 L. No significant difference between measurements was observed in the control group. Our results show that TVP significantly decreases variceal pressure and tension. These results suggest that ascites removal can be useful in the treatment of variceal bleeding in cirrhotic patients.

Esophageal and Gastric Varices↗
PubMed1997

Stable expression of pertussis toxin in Bordetella bronchiseptica under the control of a tightly regulated promoter.

Pertussis toxin (PT) is an essential component of accellular vaccines against whooping cough. However, the industrial production of PT from Bordetella pertussis is impaired by slow growth and poor yields. To overcome these problems, we have constructed a minitransposon containing the tox operon under the control of a tightly regulated promoter responsive to an aromatic inducer. The expression cassettes have been integrated into the chromosome of Bordetella bronchiseptica 5376 and ATCC 10580 bvg. Five recombinant clones containing the tox operon under the control of the Psal promoter, which is activated by the product of nahR, were further characterized. The recombinant clones expressed PT after only 3 h of induction with sodium salicylate at levels similar to those of B. pertussis grown for 24 h. The stability of the engineered phenotype was 100% after 72 h of growth without selective pressure. The growth pattern was not modified either under noninducing conditions or in the presence of the inducer at low concentrations, suggesting that strain performance would not be affected in bioreactors when uncoupled from gene expression. Recombinant PT, which was localized mainly in the periplasm, was purified by affinity chromatography. The recombinant protein was immunologically indistinguishable from wild-type PT and retained its biological activity as determined by the CHO cell-clustering test. These recombinant clones appear to be useful tools for the cost-effective production of PT under conditions of improved biosafety, as demonstrated by the inducible expression of PT uncoupled from the bacterial biomass in a nonvirulent and fast-growing B. bronchiseptica background.

Animals↗
PubMed1994

Safety, tolerability, efficacy and plasma concentrations of tropisetron after administration at five dose levels to children receiving cancer chemotherapy.

In a double-blind, placebo-controlled, escalating dose study, 44 children receiving cancer chemotherapy of various degrees of emetogenicity were randomly allocated to once-daily treatment with tropisetron 0.05 mg/kg (6 patients), 0.10 mg/kg (5 patients), 0.20 mg/kg (6 patients), 0.33 mg/kg (6 patients), 0.50 mg/kg (6 patients) or placebo (15 patients). All doses of tropisetron were well tolerated; no tropisetron recipient discontinued treatment because of intolerance and no adverse effect could be plausibly correlated to tropisetron administration. Therapeutic plasma concentrations of tropisetron (> 3 ng/ml) were present for 9 h after administration of doses of 0.10 mg/kg or more. Tropisetron at doses of at least 0.20 mg/kg was significantly more effective in preventing vomiting than lower tropisetron doses or placebo, both in terms of treatment failure (> four vomits) (P = 0.015) and patient and investigator efficacy ratings (P = 0.04 for investigator rating; P = 0.035 for patient rating). Further comparative studies of the efficacy of tropisetron in chemotherapy-induced emesis in children are warranted.

Adolescent↗
PubMed1994

Primary tubal carcinoma.

Fourteen patients were studied in a retrospective review of malignancies of the fallopian tube in the Maternity Section of La Paz Hospital, Madrid, over a period of 19 years. Three patients were excluded at reassessment. Adenocarcinoma was the most common histological type. Eight patients have survived but one of them has had a relapse. None were diagnosed prior to surgery. A comparative study of survival and stage, muscular invasion and grade of cellular differentiation was performed. It is concluded that the best results are obtained when adjuvant treatment with polychemotherapy containing platinum is used.

Adenocarcinoma↗