Search PubMed⌕ Search

Biomedical subjects

V Garcia

Publications and source records attributed to V Garcia.

70 records · Page 4Linked to original sources

Interactions of aminoacyl-tRNA synthetases in high-molecular-weight multienzyme complexes from rat liver.

The functional interaction of Arg-, Ile-, Leu-, Lys- and Met-tRNA synthetases occurring within the same rat liver multienzyme complex are investigated by examining the enzymes catalytic activities and inactivation kinetics. The Michaelis constants for amino acids, ATP and tRNAs of the dissociated aminoacyl-tRNA synthetases are not significantly different from those of the high-Mr multienzyme complex, except in a few cases where the Km values of the dissociated enzymes are higher than those of the high-Mr form. The maximal aminoacylation velocities of the individual aminoacyl-tRNA synthetases are not affected by the presence of simultaneous aminoacylation by another synthetase occurring within the same multienzyme complex. Site-specific oxidative modification by ascorbate and nonspecific thermal inactivation of synthetases in the purified rat liver 18 S synthetase complex are examined. Lys- and Arg-tRNA synthetases show remarkably parallel time-courses in both inactivation processes. Leu- and Met-tRNA synthetases also show parallel kinetics in thermal inactivation and possibly oxidative inactivation. Ile-tRNA synthetase shows little inactivation in either process. The oxidative inactivation of Lys- and Arg-tRNA synthetases can be reversed by addition of dithiothreitol. These results suggest that synthetases within the same high-Mr complex catalyze aminoacylation reactions independently; however, the stabilities of some of the synthetases in the multienzyme complex are coupled. In particular, the stability of Arg-tRNA synthetase depends appreciably on its association with fully active Lys-tRNA synthetase.

Amino Acids↗

Use of military antishock trouser in a child.

Angiographic localization and embolization has emerged as the preferred mode of therapy for arterial bleeding associated with pelvic fractures but is not always definitive. Our experience demonstrates the use of an external counter pressure device (MAST) as an essential part of the pediatric surgeon's armamentarium and suggests the need for concurrent venography during angiographic localization of pelvic bleeding sites.

Child↗

Management of splenic artery aneurysms and false aneurysms with endovascular treatment in 12 patients.

PURPOSE: To assess the endovascular treatment of splenic artery aneurysms and false aneurysms. METHODS: Twelve patients (mean age 59 years, range 47-75 years) with splenic artery aneurysm (n = 10) or false aneurysm (n = 2) were treated. The lesion was asymptomatic in 11 patients; hemobilia was observed in one patient. The lesion was juxta-ostial in one case, located on the intermediate segment of the splenic artery in four, near the splenic hilus in six, and affected the whole length of the artery in one patient. In 10 cases, the maximum lesion diameter was greater than 2 cm; in one case 30% growth of an aneurysm 18 mm in diameter had occurred in 6 months; in the last case, two distal aneurysms were associated (17 and 18 mm in diameter). In one case, stent-grafting was attempted; one detachable balloon occlusion was performed; the 10 other patients were treated with coils. RESULTS: Endovascular treatment was possible in 11 patients (92%) (one failure: stenting attempt). In four cases among 11, the initial treatment was not successful (residual perfusion of aneurysm); surgical treatment was carried out in one case, and a second embolization in two. Thus in nine cases (75%) endovascular treatment was successful: complete and persistent exclusion of the aneurysm but with spleen perfusion persisting at the end of follow-up on CT scans (mean 13 months). An early and transient elevation of pancreatic enzymes was observed in four cases. CONCLUSION: Ultrasound and CT have made the diagnosis of splenic artery aneurysm or false aneurysm more frequent. Endovascular treatment, the morbidity of which is low, is effective and spares the spleen.

Aged↗

Clinical relevance of low levels of preformed alloantibodies detected by flow cytometry in the first year post-kidney transplantation.

OBJECTIVE: To determine the prevalence of transplants performed with a false-negative cytotoxicity cross-match and to analyze the clinical relevance of alloantibodies (Ab) detected only by flow cytometry (flow). METHODS: We studied 66 patients undergoing kidney transplantation from a cadaveric donor. All patients had a simultaneous negative T+AHG+DTT and B+DTT. Pretransplant sera were retrospectively analyzed by flow cytometry according to an Emory University protocol: (1) T+ and B-: Ab anti-class I; (2) T- and B+: anti-class II; (3) T+B+: anti-class I + II. Chi-square, Fisher exact, Student t test, and Kaplan Meier analyses were employed with significance assigned at P < or = .05. RESULTS: The overall incidence of false-negative cytotoxicity was 33.3% (22/66), namely, 6.1% (n = 4) anti-class I; 9.1% (n = 6) anti-class II; and 18.2% (n = 12) anti-class I + II. Primary nonfunctioning grafts occurred in 6.8% (3/44) and 13.6% (3/22) negative and positive flow patients (two anti-class I + II and one class II; P = .39). The incidence of graft loss in the first year was respectively, 13.6% (6/44) and 18.2% (4/22; two anti-class II and two anti-class I + II; P = .72). Compared to flow-negative grafts, creatinine levels were significantly higher among flow-positive patients at 8 and 12 weeks. One-year graft survivals were 86.4% among negative versus 81.8% for the positive group (P = .67). CONCLUSIONS: We observed that 33% of kidney transplant recipients had low levels of alloantibodies detected only by flow. This single factor was associated with the worst graft function in the first trimester with a suggestion of a higher risk for non-functioning graft.

Cadaver↗

Immunoglobulin G-positive in B-cell cross-match decreases kidney allograft survival.

We retrospectively studied all 1149 transplants performed at our center between 1993 and 2003 to determine the incidence and clinical effect of pretransplant B-positive cross-match on kidney graft survival. The patients were divided in two groups: B-negative (n = 1102) and B-positive in current sera (n = 47; 4.1%). AB-positive test was more frequent among regrafted patients (14% vs 3%; P = .00). Demographic data were not different between the groups. The overall rate of graft loss was similar (26% vs 24%, respectively; P = .86). However, early nonsurgical graft losses were more frequent among B-positive patients (46% vs 20%, respectively; P = .04). IgM was the most frequent immunoglobulin in the B-positive group (76% IgM and 24% IgG). There was no significant difference between B-negative and B-positive groups in the 1-, 5-, and 10-year graft survival rates (87% vs 83%, 73% vs 78%, 64% vs 66%, respectively; P = .87). The graft survival was significantly reduced comparing an IgG anti-B cell to the B-negative group (P = .03) as well as IgG compared to IgM (P = .004). In conclusion, only B-positive cross-match due to IgG decreased graft survival. Even though it is an uncommon situation (0.9%), this study stressed the clinical value of the B-cell cross-match as a tool to identify patients with a higher immunological risk.

B-Lymphocytes↗

Antigenemia for cytomegalovirus in renal transplantation: choosing a cutoff for the diagnosis criteria in cytomegalovirus disease.

Cytomegalovirus (CMV) infection is a frequent complication in transplant recipients, causing a high level of morbidity and mortality. We studied 203 consecutive renal transplant recipients performed between January 2000 and December 2001. Patients underwent weekly measurements of CMV pp65 antigen to assess CMV activity from the 4th to the 12th week posttransplantation. The results were reported as number of cells positive for the pp65 antigen among 10(5) granulocytes. In order to define a best cutoff to diagnose CMV disease with desirable sensitivity and specificity, we used a receiver operator characteristics (ROC) curve. The cutoff of four positive cells corresponded to a sensitivity of 93% and specificity of 60% (AUC = 0.87) for the diagnosis of CMV disease. The chosen cutoff for starting antiviral treatment was 10 cells, since this was associated with a sensitivity of 92% and specificity of 70% (AUC = 0.90). In conclusion, the highly sensitive cutoff points for the diagnosis of antigenemia was four cells and 10 cells for initiation of antiviral therapy.

Antigens, Viral↗

Biochemical and histopathological findings after a long-term intraperitoneal fat infusion. An experimental study in rats.

The object of this work was to see the possible side effects that a long-term intraperitoneal (IP) fat infusion would have. We used 56 female Wistar rats weighing 250 g, divided into a control group (CG) of eight and three groups of 16 in each one. These three groups were administered a 20% Intralipid infusion in a daily amount of 4 g/kg over 5, 10, and 15 days, respectively (groups I, II, and III) intraperitoneally. Twenty-four hr after the last infusion the animals were anesthetized and after having drawn 3 ml of blood, 5% glutaraldehyde (GTH) was instilled in situ and optical and electron microscopic specimens were taken of the lung, liver, right diaphragm, and parietal peritoneum. The results show a decrease in triglyceride (TG) rate 24 hr after the last infusion in each group, but blood glucose, cholesterol, bilirubin, glucose oxidase test (GOT), glutamic pyruvic transaminase (GPT), nor other serum parameters varied. No alterations were noticed in the lung or liver under optical or electron microscopes in the groups than had under gone treatment, except for an increase in circulating macrophages with fat in the lung. In the diaphragm we observed hyperplasia in the serous layer of the peritoneum and an increase in fat in the lymphatic channels of the right diaphragm. The possibility of using IP infusions in order to study parenteral nutrition solutions was put forward as well as their possible clinical use in alternative nutrition techniques on both a short-term and long-term basis.

Animals↗

[The embolization of complicated renal angiomyolipoma].

A case of complicated renal angiomyolipoma with tumoral bleeding in a 44-year-old woman is presented. The contribution of angiography to the diagnosis helped clarify the degree of vascularity, and the contribution of embolization treatment (safe and well tolerated) is discussed.

Adult↗

Monoclonal antibody-based detection system for Salmonella enteritidis.

Two monoclonal antibodies that react with Salmonella enteritidis in chicken tissue, eggs, and environmental samples were used to develop a rapid enzyme-linked immunosorbent assay (ELISA) screen and agglutination assay for the specific detection of S. enteritidis. S. enteritidis was detected in 100% of egg samples and 99.8% of various field and research samples by both ELISA and traditional microbiological isolation and identification techniques. Results of titer experiments indicate that as few as 10(4) organisms can be detected by ELISA.

Animals↗