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Biomedical subjects

R Garcia

Publications and source records attributed to R Garcia.

At least 163 records · Page 9Linked to original sources
PubMed1996

Cloning of the Penicillium minioluteum gene encoding dextranase and its expression in Pichia pastoris.

The DEX gene encoding an extracellular dextranase was isolated from the genomic DNA library of Penicillium minioluteum by hybridization using the dextranase cDNA as a probe. Comparison of the gene and cDNA sequences revealed that the DEX gene does not contain introns. Amino acid sequences comparison of P. minioluteum dextranase with other reported dextranases reveals a significant homology (29% identity) with a dextranase from Arthrobacter sp. CB-8. The DEX gene fragment encoding a mature protein of 574 amino acids was expressed in the methylotrophic yeast Pichia pastoris by using the SUC2 gene signal sequence from Saccharomyces cerevisiae under control of the alcohol oxidase-1 (AOX1) promoter. Over 3.2 g/l of enzymatically active dextranase was secreted into the medium after induction by methanol. The yeast product was indistinguishable from the native enzyme in specific activity and the N-terminus of both proteins were identical.

Amino Acid Sequence↗
PubMed1996

Functional reconstitution of oxidase activity in X-linked chronic granulomatous disease by retrovirus-mediated gene transfer.

The feasibility of correction of the disease phenotype by gene gene transfer was investigated in cells of four patients with X-linked chronic granulomatous disease. These patients carry point mutations of the gp91-phox gene, encoding for the large subunit of the catalytic core of the phagocytic cell NADPH oxidase. A retroviral vector expressing the gp91-phox protein was constructed and used to transduce lymphoblastoid cell lines established from the patients. Several transduced lymphoblastoid cell clones were investigated for mRNA and protein expression, and for functional reconstitution of oxidase activity. Although extensive quantitative variability was detected among different clones, functional reconstitution of O2- production was obtained in most cases, with oxidase function within the same range as in B cell lines derived from normal individuals. The same vector was also used for transduction of hematopoietic precursors from bone marrow or peripheral blood either with or without enrichment for CD34+ cells. A comprehensive analysis was performed on differentiated myeloid colonies, to evaluate the efficiency of transduction, the levels of gp91-phox expression, and the extent of functional reconstitution of oxidase activity. A high efficiency of transduction was obtained in most experiments, with 60-100% of colonies containing proviral DNA. Among the transduced colonies, an extensive variability in the levels of expression of the transduced gene and of functional restoration of NADPH oxidase activity was observed. These results represent a step toward the development of a gene therapy protocol for these patients.

3T3 Cells↗
PubMed1996

[Analysis of response to interferon alpha-2b and the significance of antinuclear antibodies in hairy cell leukemia].

Hairy cell leukemia is a uncommon B-cell chronic lymphoproliferative disease rarely associated with autoimmune phenomena. We present a positive CD 5 case with a positive antinuclear antibodies test in the absence of any relation to any other clinical autoimmune disease syndrome and we analyse the evolutive profile of serum concentration of several factors with prognostic significance, relating to the interferon alpha-2b treatment: C reactive protein, beta 2-microglobulin and erythropoietin presented at first very high basal levels that descended progressively until the last two normalized completely; the tumor necrosis factor-alpha manifested stable with normal values during the whole study; the gamma-interferon and interleukin-6 revealed a precocious increase at the start of the treatment later returning to their basal levels. These parameters may aid to assess the response to treatment in these patients.

Aged↗
PubMed1996

The sequence of a 20.3 kb DNA fragment from the left arm of Saccharomyces cerevisiae chromosome IV contains the KIN28, MSS2, PHO2, POL3 and DUN1 genes, and six new open reading frames.

We report the sequence of a 20 300 bp DNA fragment from the left arm of Saccharomyces cerevisiae chromosome IV. This segment contains 13 complete open reading frames (ORFs) and part of another ORF, altogether covering 84.2% of the entire sequence, five of which correspond to the previously characterized KIN28, MSS2, PHO2, POL3/CDC2 and DUN1 genes. One putative protein, D2358p, shares considerable homology with an O-sialoglycoprotein endopeptidase from Pasteurella haemolytica serotype A1. The putative product of D2325 contains the characteristic consensus motif of triacylglycerol lipases. D2320p and D2352p have a putative 'leucine-zipper' structure and a RNA-binding region Rnp-1 signature, respectively.

Amino Acid Sequence↗
PubMed1996

Characterization and hemodynamic implications of renal vascular angiotensin II receptors in SHR.

The intrarenal renin-angiotensin system (RAS) contributes to the increased renal vascular resistance and reactivity observed in spontaneously hypertensive rats (SHR) and to the pathogenesis of high blood pressure (BP). Thus, we decided to characterize angiotensin II (ANG II) receptors in the renal arteries and glomeruli of 16-week-old SHR and their age-matched, normotensive Wistar-Kyoto (WKY) controls. SHR had significantly higher BP (153 +/- 4 v 96 +/- 10 mmHg) and heart weight (440 +/- 5 v 327 +/- 4 g/100 g body weight) than WKY rats. There was no difference in plasma renin activity between strains. Radioligand binding assays using non-peptide antagonists for AT1 (losartan) and AT2 (PD 123319) showed that renal preglomerular microvessels and glomeruli expressed a single receptor population (AT1) for ANG II. AT1 density tended to be lower in glomeruli of SHR compared to WKY (377 +/- 45 v 555 +/- 74 fmol/mg protein), but was significantly higher in preglomerular vessels (93 +/- 7 v 57 +/- 1 fmol/mg protein). No difference in receptor affinity was found in either preparation. Isolated kidney perfusion revealed that at low flow (3-10 ml/min), perfusion pressure was similar in both strains; however, at higher flow levels, SHR showed higher reactivity and less compliance than their controls. In addition, SHR presented a higher renal vascular reactivity to ANG II (but not to arterenol) than WKY rats. Thus, upregulation of ANG II receptors in the renal vasculature may mediate the hyperreactivity to ANG II observed in SHR kidney.

Angiotensin II↗
PubMed1996

Protective effects of the calcium channel blocker verapamil on hepatic function following warm ischemia.

The purpose of this study was to investigate the protective effects of the calcium channel blocker verapamil on warm ischemia-reperfusion injury to the liver using a rat model. Ischemia of the left and median lobes was created by total inflow occlusion for 60 min followed by 24 hr of reperfusion. Hepatocell injury was assessed by the release of liver enzymes [alanine aminotransferase (ALT) and lactic dehydrogenase (LDH)], reduced (GSH) and oxygenated (GSSG) plasma glutathione and total biliary glutathione. Hepatocyte function was quantitated by measuring bile flow. Rats were randomized to one of two groups: pretreatment with iv verapamil (0.3 mg/kg) or iv normal saline (controls). Verapamil significantly increased bile flow and GSH efflux while decreasing plasma ALT and LDH compared to those in controls 24 hr after liver ischemia-reperfusion (LIR). A significant correlation existed between bile flow and biliary GSH efflux at 1 but not 24 hr after LIR, suggesting that early LIR injury is mediated predominantly by generation of oxygen free radicals. Liver enzyme elevation and bile flow were inversely correlated at 24 but not 1 hr after injury. We conclude that verapamil significantly protects the liver against warm LIR injury. The minimal protective effect of verapamil on early liver ischemia-reperfusion demonstrates that verapamil does not prevent the early generation of oxygen radicals upon reperfusion. However, the significant restoration of biliary GSH efflux and hepatocyte protection at 24 hr suggests involvement of calcium ions in late hepatocyte injury. Verapamil's protective effects may be related to attenuating pathophysiologic events occurring beyond 1 hr of reperfusion. Future studies investigating the protective effects of verapamil on warm LIR injury should be carried out for at least 24 hr postreperfusion.

Alanine Transaminase↗
PubMed1996

In vitro study of the potential role of quinupristin/dalfopristin in the treatment of catheter-related staphylococcal infections.

The susceptibility of clinical isolates of methicillin-susceptible and -resistant staphylococci from cancer patients with central venous catheter bacteremia to quinupristin/dalfopristin, a semisynthetic streptogramin, was determined in vitro. Susceptibility of these isolates to nine other antistaphylococcal antibiotics was also determined for comparison. A total of 197 staphylococcal strains were tested from 1983 to 1992. Quinupristin/dalfopristin was bactericidal against all isolates, independent of their resistance to methicillin. Its activity was similar to that of vancomycin but superior to that of teicoplanin. Quinupristin/dalfopristin may prove to be an important addition to our armamentarium against catheter-related staphylococcal infections.

Anti-Bacterial Agents↗
PubMed1996

Specific potentiation by cyclic AMP of natriuretic peptide-mediated cyclic GMP production in adipose tissue.

Adipose tissue of the mesenteric territory contains large quantities of natriuretic peptide receptors (NPR) mainly of the NPR-C subtype. Guanylyl cyclase-bound receptors are also present since atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) are equally potent in activating this enzyme. While searching for a potential biological role for NP in adipocytes we observed that ANP-mediated generation of cyclic GMP (cGMP) was potentiated when the cells were simultaneously treated with isoproterenol. Indeed, isoproterenol, a beta-adrenergic agonist, and forskolin, an activator of adenylyl cyclase, can both double or triple cGMP production in response to ANF stimulation. There was a direct correlation between the level of cyclic AMP (cAMP) generated and the level of NP-mediated cGMP production suggesting that a cAMP-dependent mechanism may be responsible of this potentiation. To determine whether or not this phenomenon was unique to adipocytes, NPR subtypes were characterized in 4 established cell lines and their cAMP-dependent cGMP behavior examined. A10 and A7r5 smooth muscle cells showed identical ratio of NPR subtypes with about 95% NPR-C and 5% NPR-B. PC12 cells presented 100% NPR-A and NIH 3T3 fibroblasts 50% NPR-C and 50% NPR-B. Regardless of the NPR subtype, forskolin could not potentiate the cGMP generation in these cell lines. These data indicate that the cAMP-dependent potentiation of the NP-mediated cGMP production is unique to adipocytes, appears independent of the guanylyl cyclase-linked NPR subtypes and may be involved in the sensitization of the guanylyl cyclase domain of NPR for a potential biological role of NP in the adipose tissue.

3T3 Cells↗
PubMed1996

Evaluation of the monitoring of papular dermatitis lesions in slaughtered swine to assess sarcoptic mite infestation.

We investigated the association between the presence of papular dermatitis and sarcoptic mite infestation in pigs slaughtered in southern Minnesota. Following dehairing, a sample of 30 pigs from each of 50 herds was inspected for papular dermatitis lesions. Herds were selected after being categorized into one of five categories according to the prevalence and severity of dermatitis lesions. Herd infestation with sarcoptic mange was determined by recovery of mites from ear scrapings of slaughtered pigs and also by survey of producer opinion. Mite infestation was detected in 28 herds (56%) and 215 of 1500 pigs (14%). Considerable variability in prevalence of positive scrapings, ranging from one pig (3%) to 19 pigs (63%), was found among infested herds. Prevalence of mite infestation was positively associated with severity of papular dermatitis lesions in groups. For individual pigs, estimates of the specificity of localized lesions ranged from 0.70 to 0.90. Generalized lesions appear highly specific (> 0.98) for sarcoptic mite hypersensitivity. Generalized lesions occurred in 36.7% of pigs from herds confirmed to be infested, compared with 0.4% of pigs in herds confirmed free from mange. Our date indicate that monitoring of dermatitis lesions in slaughtered pigs might be a useful test for sarcoptic mange in the Midwest, USA.

Abattoirs↗
PubMed1996

[Management policy and utilization of botanical resources in the Dominican Republic].

The Dominican Republic has an extension of 48 442 km2. It occupies the eastern portion of the island of Hispaniola and is the second in size within the Greater Antilles. The floral resources of the Island have been extensively exploited without an adequate management policy. This has led to the destruction of about 90% of the forested lands of the country. The Dominican Republic has about 5600 species of vascular plants, of which 36% are endemic, many of which are in danger of extinction, due to overexploitation and/or destruction of the habitats. In order to protect the biodiversity of the Dominican Republic, 22 nature preserves were created, representing about 13.3% of the national territory. The primary institutions charged with the management and protection of the flora are the General Directorate of Forests, National Directorate of Parks, the National Botanical Garden, and the Department of Wild Life under the State Secretary of Agriculture (SEA). Numerous laws, resolutions and decrees have been promulgated, governing forest resources. As to the wildlife, emphasis is given to the protection of the fauna. At present, there is a technical body, which is structuring a Forest Code. Export of products of the wild flora is regulated by the Wildlife Department under the State Secretary of Agriculture (SEA). This Department also administers regulations for CITES. The Department of Plant Sanitation of the SEA and the Dominican Centre of Export Promotion (CEDOPEX) are also involved in the control of the export of biological materials.

Animals↗
PubMed1996

[High-dose rate endobronchial brachytherapy: results and complications in 189 patients].

Between September 1990 and March 1995, 189 patients were treated with high-dose-rate endobronchial brachytherapy. Most patients (70%) presented with either recurrent or persistent symptomatic endobronchial tumor after standard therapy. A minority of the patients (12%) had small endobronchial tumor and were unfit for surgical resection or radiotherapy. Treatment was delivered weekly and consisted of three to four 8- to 10-Gy radiotherapy fractions applied at 10 mm from the source. Major symptomatic improvement was obtained on hemoptysis (74%), dyspnea (54%), and cough (54%). Complete endoscopic response occurred in 54.5% of the cases. Median survival was 7 months for the entire group. For small strictly endobronchial tumors, complete response rate was 95.5%, median survival was 17 months, and 30-month survival was 46%, with a plateau starting at 18 months. The rate of late grade 3 to 4 toxicity was 17%, including hemoptysis (n = 13), stenosis (n = 12), local necrosis (n = 8), and bronchial fistula (n = 3). By univariate analysis, no factor was found to be predictive of late toxicity. Our study confirms the benefit of endobronchial brachytherapy in the palliative treatment of endobronchial recurrences and in the curative intent treatment of small endobronchial tumors in patients not suitable for other forms of therapy.

Adult↗
PubMed1996

Effects of nedocromil sodium in steroid-resistant asthma: a randomized controlled trial.

BACKGROUND: Some patients with asthma respond poorly to corticosteroids and have persistent airway inflammation and daily clinical symptoms. The aim of this study was to investigate the effects of nedocromil sodium (NS), a nonsteroidal antinflamatory drug, in the treatment of steroid-resistant asthma. METHODS: Steroid-resistant asthma as diagnosed in any patient who demonstrated 20% improvement in FEV1 after treatment with inhaled salbutamol with failure of FEV1 to improve by at least 15% after a 2-week trial of prednisolone, 30 mg daily. In a double-blind placebo-controlled trial, the patients received either 4 mg of inhaled NS (n = 13) or placebo (n = 13), 4 times daily for 3 months. RESULTS: NS but not placebo resulted in a mean increase in FEV1 of 11.4% after 12 weeks of therapy (p = 0.05) and of 12.4% (p = 0.04) and 15% (0.02) in morning peak expiratory flow after 8 and 12 weeks of treatment, respectively. Changes in FEV1 at 4 and 8 weeks and in peak expiratory flow at 4 weeks of NS therapy were not significant. NS was also effective in reducing variability of peak expiratory flow (p = 0.02) and use of salbutamol (p = 0.005) and in improving quality of life (p = 0.007) by the trial end. Six of the 12 patients treated with NS who completed the treatment period showed a "good response," defined by a reduction in salbutamol use of more than 50% and an increase in morning peak expiratory flow of more than 20% from baseline; there were no clinical predictors of this response. Two patients were withdrawn from the study because of severe asthma exacerbation (one from each treatment group). CONCLUSION: Inhaled NS improved pulmonary function and decreased asthma severity in steroid-resistant asthma, but its effectiveness is not homogeneous and cannot be predicted from baseline clinical data.

Adult↗
PubMed1996

Validation of a severity score for the assessment of crotalid snakebite.

STUDY OBJECTIVE: No research tool exists for the clinical evaluation of crotalid snakebite. We sought to determine the correlation of the snakebite severity score (SSS) with the clinical assessment of physicians experienced in the management of crotalid snakebite. METHODS: We retrospectively used the SSS to quantify the severity of envenomation in 108 patients with crotalid snakebite. Two physicians experienced in the management of venomous snakebite independently and blindly assessed the severity of envenomation as detailed in medical records with the use of accepted clinical criteria. The correlation of the SSS and the physicians' consensus was determined with pointbiserial correlation. RESULTS: The SSS correlated well with the physicians' consensus at presentation (r=+.63, z score=6.52, P<.000001) and at the point at which the patient's condition was worst (r=+.70, z score=7.24, P<.000001). The SSS also correlated highly with the physicians' assessment of change in the patient's condition (r=+.51, z score=6.10, P<.000001). With the physicians' consensus as the gold standard, the sensitivity of a change in the SSS of 1 point in detecting clinically significant worsening of the envenomation syndrome was .97; specificity was .81. CONCLUSION: The SSS correlated well with the clinical condition of patients bitten by crotalid snakes as represented by the medical record. It provides a more objective instrument for the evaluation of severity and progression of envenomation in patients with crotalid snakebite.

Animals↗
PubMed1996

The relationship between cervical whiplash and temporomandibular joint injuries: an MRI study.

Temporomandibular joint (TMJ) symptoms are a common finding in motor vehicle accident (MVA) patients with hyperextension/hyperflexion injuries of the cervical spine (cervical whiplash). The relationship between cervical whiplash and TMJ injuries was documented with magnetic resonance imaging (MRI) in 87 consecutive MVA cervical whiplash patients who presented with TMJ symptoms and had sustained no direct trauma to the face, head or mandible and had no TMJ complaints prior to the MVA. One hundred sixty-four TMJ patients were evaluated for internal derangement, effusion and inflammation, utilizing T1 and T2 weighted images. A high percentage of the TMJ patients demonstrated abnormal findings: disk displacement with reduction (DDR), 118/164 (72%); disk displacement without reduction (DDNR), 25/164 (15%); effusion, 113/164 (69%); inflammation or edema, 84/164 (51%); total TMJ abnormalities, 156/164 (95%). The high percentage of TMJ abnormalities in this study significantly illustrates the proximate relationship between cervical whiplash and TMJ injuries.

Accidents, Traffic↗
PubMed1996

Expression of lysosomal acid lipase mutants detected in three patients with cholesteryl ester storage disease.

Lysosomal acid lipase (LAL) gene mutations were identified in three patients with cholesteryl ester storage disease (CESD). Direct sequencing of genomic DNA revealed that: patient 1 was a compound heterozygote for a P181L mutation and an A to G3' splice site substitution that causes skipping of exon 7, with a loss of 49 amino acids from LAL (delta 205-253); patient 2 was a compound heterozygote for a G66V mutation and a 5' splice site mutation (G to A) that leads to skipping of exon 8 (delta 254-277); and patient 3 was a compound heterozygote for a L273S mutation and an unidentified null allele. Furthermore, patients 2 and 3 showed a novel G-2A polymorphism that could be detected by an Xbal restriction fragment length polymorphism. All these mutants and a previously reported H274Y allele were expressed in vitro in HeLa cells using the vaccinia T7 expression system. The resulting recombinant proteins were inactive towards cholesteryl oleate and trioleylglycerol, demonstrating the direct involvement of these mutations in the pathogenesis of CESD. Immunoblotting of normal LAL expressed in HeLa cells revealed four major molecular forms, at least two of high molecular mass (54 and 50-51 kDa) and two of low molecular mass (42 and 43 kDa). L273S and P181L substitutions and delta 254-277 were shown to result in altered LAL molecular forms, some of which suggest that post-translational processing may interfere with the catalytic activity of LAL.

Child↗
PubMed1996

Use of large gamma-ray detector to measure 131I in milk and water at low levels.

A lower limit of detection of 0.04 Bq L-1 for measuring 131I in milk or water with a gamma-ray spectrometer was achieved with a large 118% intrinsic germanium detector. Three-liter samples with 131I tracer in a reentrant beaker were counted within a lead shield for 12,000 to 55,000 s to demonstrate detection at this concentration. Samples of milk collected at dairies and counted for 28,000 s showed no 131I at this level (as expected), but 137Cs from fallout was detected in some samples near its detection limit of 0.03 Bq L-1.

Animals↗