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Biomedical subjects

A García

Publications and source records attributed to A García.

At least 307 records · Page 17Linked to original sources
PubMed1994

Frequency of HLA-DPB1 alleles in a Spanish population: their contribution to rheumatoid arthritis susceptibility.

HLA-DPB1 allele frequencies in 181 unrelated control individuals and 70 rheumatoid factor-positive RA patients from Seville (Spain) were determined using oligonucleotide typing methods. All frequencies shown concern the percentage of individuals positive for a certain allele. HLA-DPB1*0401 was the most common DPB1 allele in the healthy individuals, possessed by 65.7% of them. In addition to HLA-DPB1*0401, only the following alleles were found in normal subjects at frequencies greater than 10%: DPB1*0101 (15.5%), DPB1*0201 (12.2%), DPB1*0301 (16.6), and DPB1*0402 (29.3%). When HLA-DPB1 allelic frequencies were compared between seropositive RA patients and controls, a negative association for DPB1*0301 and DPB1*0401 was found in RA patients, although it failed to reach statistical significance after correction for the number of comparisons made. The other DPB1 alleles exhibited almost identical frequencies in both groups. However, when only DR4+ patients and controls were considered, the decrease in the frequency of the DPB1*0301 and DPB1*0401 alleles lacked statistical significance. On the other hand, when DR4- RA patients and controls were compared, the frequency of DPB1*0301 was found decreased significantly again, even more than in the whole group of patients.

Alleles↗
PubMed1994

Partial Removal of Lipopolysaccharide from Thiobacillus ferrooxidans Affects Its Adhesion to Solids.

Conditions for the partial removal of lipopolysaccharide (LPS) from Thiobacillus ferrooxidans are described. Raising the pH of the solution containing the cells from pH 1.5 to pH 6.8 to 8.0 releases about 50% of the LPS without cell lysis. The release of LPS begins at pH 3.5, and it was not affected by EDTA concentration. Partial removal of LPS exposed higher amounts of a 40-kDa outer membrane protein in the bacteria, as detected by a dot immunoassay employing an antiserum against the T. ferrooxidans surface protein. This higher protein exposure and the reduced LPS content increased the hydrophobicity of the cell surface, as determined by an increased adhesion (50%) to hydrophobic sulfur prills and C-dodecanoic acid binding (2.5-fold) compared with control cells. In addition, adhesion of radioactively labeled microorganisms to a sulfide mineral was inhibited (40%) in the presence of previously added LPS. Our results suggest that not only LPS but also surface proteins probably play important roles in T. ferrooxidans adhesion to solid surfaces.

Journal Article↗
PubMed1994

Comparison of techniques and evaluation of three commercial monoclonal antibodies for laboratory diagnosis of varicella-zoster virus in mucocutaneous specimens.

A comparison of direct antigen detection in cell scrapings with culture techniques (tube culture and shell vial method) for diagnosis of varicella-zoster virus (VZV) mucocutaneous infections was done in parallel in two groups of specimens. A total of 100 specimens were from patients with clinical diagnosis of VZV infection (group 1), and 69 were from patients with no suspicion of VZV infection (group 2) but mainly with herpes simplex virus infections. In addition, three commercially available monoclonal antibodies (Whittaker, Biosoft Clone 2013, and Ortho 3B3) directed against VZV antigens were evaluated in parallel in the last 87 group 1 specimens. Overall, 80% of the group 1 specimens were confirmed positive by direct detection, in comparison with 56% positive by tube culture and/or shell vial. None of the group 2 specimens were positive for VZV by any of the methods, and none of the monoclonal antibodies assayed reacted with any herpes simplex virus stock strains. Antiviral therapy and the length of evolution time of lesions affected negatively the performance of all laboratory methods, but to a lesser extent in direct detection techniques than in culture techniques. The Whittaker and Biosoft reagents (indirect immunofluorescence assay) showed statistically significant differences in sensitivity with respect to the Ortho antibody (P = 0.002 and P = 0.039, respectively; two-tailed binomial test). Direct antigen detection is a rapid, easy-to-perform, sensitive, and specific technique and appears to be the method of choice for laboratory confirmation of VZV mucocutaneous infections.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Evaluation of commercial kits used for Chagas disease diagnosis in blood banks in Chile. II. Routine application].

Aiming to study the applicability and reproducibility of four commercial kits used for the serological detection of Chagas disease (Chagatest-Inst Invest Paraguay, Ortho Chagas, Abbott Chagas (ELISA tests) and Estabilgen Hemo Chagas (indirect hemagglutination test)), a comparative serological study was performed in 256 sera samples coming from a highly endemic area, 249 samples from a low endemic area, 180 reference sera and 2264 samples coming from three blood banks. Specificity of the kits was excellent and sensitivity ranged from 60 to 100%. The indirect hemagglutination test has the lower sensitivity. Some disagreements in the results were observed in the three blood banks, probably due to an unsatisfactory reactive management. We conclude that ELISA tests should be recommended for routine detection of Chagas disease and that for this purpose, a net of laboratories under the direction of a national reference center should exist. This center should assess new commercial products, train technicians and supervise the laboratories.

Blood Banks↗
PubMed1994

Epithelial alterations adjacent to invasive squamous carcinoma of the vulva.

The slides of 64 vulvectomy specimens from vulvar squamous carcinoma were reviewed in order to study the histopathologic changes adjacent to the neoplasia. Normal epithelium was found in 7 cases (11%) and epithelial alterations adjacent to carcinoma in 59 (89%). The epithelial alterations found were: nonneoplastic epithelial disorder (NNDV) in 38 cases (59%) and vulvar intraepithelial neoplasia (VIN) in 19 (30%). The distribution of NNDV was: 20 cases of epithelial hyperplasia (EH) (31%), 6 of lichen sclerosus (9%) and 12 of the mixed type (19%). Sixteen cases of VIN 3 (25%) were undifferentiated, and three cases were differentiated VIN. Eighteen of 19 VIN cases were associated with NNDV, and 8 cases of undifferentiated VIN were associated with human papillomavirus infection. There was no apparent relationship between the associated lesions and tumor size, depth of invasion, lymph node metastases and clinical stage. Nevertheless, we found a significantly higher frequency of associated lesions in poorly differentiated tumors (P > .01). The most important finding was a high association between EH (50%) and VIN (30%) with carcinoma. VIN cases were almost always (95%) associated with EH.

Biopsy↗
PubMed1994

[Chlamydia trachomatis and tubal obstruction sterility].

In order to determine the importance of Chlamydia trachomatis in infertility due to tubal occlusion, the prevalence of C. trachomatis antibody was studied in two populations of Argentine women, pregnant and infertile with tubal occlusion. IgG and IgM against C. trachomatis were determined by indirect immunofluorescence in McCoy cells infected with strain L2Bu434 of C. trachomatis. In infertile women, specific anti-C. trachomatis IgM was detected in 5 out of 32 (15.6%) and IgG in 20 out of 32 (75%). In pregnant women, specific IgM was detected in 4.8% (4/83) and IgG in 20.5% (17/83). The frequency of IgG detection was significantly higher in infertile than in pregnant women (p < 0.000). Thirteen out of 20 (65%) women who underwent laparoscopic examination had evidence of chronic inflammatory disease described as yellowish viscous cysts resembling "frog eggs" in Douglas, utero and/or perihepatitis. Twelve out of fourteen (86%) infertile women with positive serology for C. trachomatis presented one or more of these laparoscopic findings. C. trachomatis antigen was detected in 2 out of 10 tubal biopsies by direct immunofluorescence with monoclonal antibodies although isolation in McCoy cells was negative. Our results show the importance of C. trachomatis in infertility due to tubal occlusion and the need of C. trachomatis diagnosis in routine gynecologic analysis to prevent infertility and neonatal infection.

Adolescent↗
PubMed1994

[Bacteriologic study of 80 cases of acute otitis media in children].

BACKGROUND: Etiology of acute otitis media (AOM) in children is almost unknown in our country. We report 80 cases in order to study the most common pathogens. METHODS: Eighty healthy children diagnosed of acute otitis media were studied between June 1989 and March 1992. Tympanocentesis was performed on each patient with an Abbocath-20G needle connected to a sterile syringe. RESULTS: Some pathogens was isolated in 58 patients (72.5%) and in 22 (27.5%) the culture was sterile or with usual flora of the external canal. S. pneumoniae was recovered in 26 cases (32.5%); H. influenzae in 23 cases (28.7%); S. pyogenes 4 cases (5%); E. coli 4; P. aeruginosa 3 (3.7%); S. aureus 2 (2.5%); anaerobes 2 cases. M. catarrhalis was not found in any cases. In 6 children there was mixed flore. CONCLUSIONS: In 80 children with AOM some pathogens was isolated in 58 cases (72.5%). The most common agents were S. pneumoniae and H. influenzae.

Acute Disease↗
PubMed1994

[Clindamycin-primaquine in the treatment of Pneumocystis carinii pneumonia].

BACKGROUND: The efficacy of clindamycin-primaquine as treatment of Pneumocystis carinii pneumonia (PCP) is similar to that of trimethoprim-sulfamethoxazol and endovenous pentamidine. The untoward effects of this combination are scarce and of mild degree. METHODS: Patients presenting with microbiologically confirmed PCP (bronchoalveolar lavage or induced sputum) were treated with clindamycin-primaquine. Patients presenting PO2 of less than 60 mmHg were excluded, being therefore treated with conventional therapy. RESULTS: Sixteen patients received treatment with clindamycin-primaquine. All demonstrated clinical improvement after the fifth day of treatment. Treatment was discontinued in three patients due to cutaneous adverse reactions. One patient voluntarily discontinued treatment, being readmitted with acute respiratory failure, and died. Clinical cure was achieved in 13 patients who completed the treatment with clindamycin-primaquine. CONCLUSIONS: The combination of clindamycin-primaquine was effective as the treatment of Pneumocystis carinii pneumonia in the patients here reported. The percentage of patients who presented secondary effects was not greater than expected with other therapeutic options. The severity of the adverse events was mild and easy to control.

Adult↗
PubMed1994

Treatment of experimental endocarditis caused by penicillin-resistant Streptococcus sanguis with different doses of teicoplanin.

Streptococcus viridans continues to be the most frequent causal agent of infective endocarditis. Treatment has become more complicated due to the increase in resistance to penicillin and cephalosporins. In order to study the possible efficacy of teicoplanin at low and high doses, this antibiotic was investigated in rabbits as a monotherapy and in association with gentamicin. The effects were compared with a control group and a group given classical penicillin-gentamicin treatment. Infective endocarditis was induced in 120 rabbits with a clinical isolate of Streptococcus sanguis. Treatment was started 48 h after infection, and lasted 5 days. Animals were divided into 6 groups of 20 rabbits each: G1, untreated controls; G2, penicillin+gentamicin; G3 low-dose teicoplanin; G4, low-dose teicoplanin+gentamicin; G5, high-dose teicoplanin; and G6, high-dose teicoplanin+gentamicin. Response to therapy was evaluated with mortality curves, negativization of blood cultures, concentration of S. sanguis in aortic vegetations and rate of sterilization of vegetations. Vegetation weight was significantly lower in treated groups than in controls; lower weights were found in G4, the only treatment that sterilized 65% of vegetations. Death occurred only in the control group (10% mortality). Negativization of blood cultures was greatest and most rapid in G4, followed by G6. Concentrations of S. sanguis in aortic vegetations were significantly lower in all treated groups compared with controls, with the lowest being in groups G4 and G6. Combined treatment with teicoplanin+gentamicin may be highly efficacious in patients with endocarditis caused by penicillin-resistant Streptococcus sanguis. High-dose teicoplanin+gentamicin does not seem to be more efficacious than low-dose teicoplanin+gentamicin.

Animals↗
PubMed1994

New toxicity determination method that uses fluorescent assay of Escherichia coli.

We describe a new method that uses a fluorogenic bioassay of the beta-glucuronidase conversion of 4-methylumbelliferyl beta-D-glucuronide (MUG) to 4-methylumbelliferone to evaluate the individual toxic effects on Escherichia coli of Al3+, Cr6+, Hg2+ and Li+. This work was designed to examine the effectiveness of this method to measure the effects of five ionic concentrations of either Al3+, Cr6+, Hg2+ or Li+, on the growth of E. coli in a minimal medium that had MUG as the only source of carbon. This method was simple and fast, and its toxicity detection sensitivity was equal to, or greater than, existing bacterial bioassays. The use of the MUG substrate minimized the danger of interference by bacteria other than E. coli. Evaluations of toxicity in samples of public drinking water proved equally sensitive.

Aluminum↗
PubMed1994

[Changes in the cellular proliferation of the healthy mucosa in patients with colorectal cancer].

AIM: To analyze differences in the proliferative pattern of normal mucosa between patients with colorectal cancer and healthy subjects. PATIENTS AND METHODS: By using flow cytometry we examined the proliferative pattern (Proliferative Index and S-Phase) in samples of normal mucosa from 34 patients operated on for colorectal cancer at our hospital and from 14 healthy subjects as a control group. RESULTS: All examined samples were diploid. The Proliferative Index and S-Phase in the Cancer Group were significantly higher than in the Control Group (16.7 +/- 5.9 vs 11.4 +/- 4, p < 0.003, and 11.9 +/- 3.9 us 6.6 +/- 3 p < 0.0004). CONCLUSIONS: These findings provide evidence for an altered proliferative pattern in the healthy colonic mucosa of patients with colorectal cancer.

Adult↗
PubMed1993

[Primary non-Hodgkin's lymphoma of the breast].

Primary non Hodgkin's lymphoma of the breast (PNHLB) its an unusual presenting form of malignant breast diseases. Its estimated frequency is around 0.05-0.5% of all breast tumors. Three cases of PNHLB are presented. We analyse the characteristics of presenting features and also we discuss the therapeutic and prognostic implications. They can be initially confused with a typical breast carcinoma due to the unspecific clinical findings with the difficulty to obtain a definitive diagnosis based only on cytologic grounds. The therapeutic and prognostic consequences underlines the importance of immunohistochemistry in the diagnosis of PNHLB.

Adult↗