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Biomedical subjects

M Matos

Publications and source records attributed to M Matos.

At least 19 recordsLinked to original sources
PubMed1997

The novel HLA-DRB1*0807 allele is present in a Carib Amerindian population: the Yucpa.

Nucleotide sequences of five novel HLA-DRB1*08 alleles have been recently reported but their frequency in different populations is still unknown. The presence of DRB1*08 variants among Carib-speaking Yucpa Amerindians of the Perijá Range in the border between Colombia and Venezuela was tested by PCR-DNA typing. DRB1*0807 was the only DRB1*08 variant found in this population with a frequency of 0.1250. Until very recently, DRB1*0802 was the predominant DRB1*08 allele present among full-blooded Amerindians, but in the last 3 years DRB1*0804 has been found in 2 South American tribes and *0811 in 2 North American tribes. The description of a new functional DRB1*08 variant in Amerindians suggests that extensive gene polymorphism among Amerindians might not be limited to the HLA-B Class I locus.

Alleles↗
PubMed1996

Enzymatic and biochemical probes of residues external to the translocation pathway of UhpT, the sugar phosphate carrier of Escherichia coli.

Part of the substrate translocation pathway through UhpT, the Escherichia coli sugar phosphate carrier, has been assigned to a transmembrane helix extending between residues 260 and 282. To set limits on the external portion of the pathway, we identified nearby residues fully exposed to the periplasm. In one case, we used Western blots to evaluate cleavage by extracellular trypsin. The protease cleaved UhpT variants retaining lysine 294, but not those lacking lysine 294, indicating that trypsin acts at a single extracellular site, lysine 294. In other work we labeled single-cysteine variants with 3-(N-maleimidylpropionyl)biocytin and scored accessibility to extracellular streptavidin by shifts of SDS-polyacrylamide gel electrophoresis mobility. Positions 283 and 284 were fully exposed to the periplasm, since the modified residue was bound by streptavidin in the native protein; by contrast, although the biotin-linked probe modified position 276, streptavidin decoration was not achieved without protein denaturation. We conclude that a 12-residue stretch(283-294) of UhpT is sufficiently exposed to be accessible to large probes (trypsin, streptavidin), while position 276 and more proximal residues are more deeply buried or otherwise shielded from the external phase.

Amino Acid Sequence↗
PubMed1996

[Abdominal pseudotumor and Whipple's disease].

Whipple's disease is an uncommon systemic disease which most often affects the intestine but may involve any other organ. The case of a woman who consulted for weight loss, fever of unknown origin, cutaneous eruptions and increase in the abdominal perimeter is presented. The ascitic fluid showed exudate infected by E. coli suggesting spontaneous bacterial peritonitis associated with chronic liver disease. Antibiotic treatment and diuretics were administered after which abdominal exploration demonstrated the presence of a mesogastric mass. Echographic and tomographic studies were unable determine the origin of the mass with the final diagnosis being achieved by exploratory laparotomy and biopsy.

Abdomen↗
PubMed1995

Extended HLA haplotypes among the Bari Amerindians of the Perija Range. Relationship to other tribes based on four-loci haplotype frequencies.

Extended HLA haplotypes among Bari Amerindians living at the Perija Range on the limits between Colombia and Venezuela have been defined using serology for class I, electrophoresis and immuno-fixation for Bf and C4, and PCR-SSO for class II loci typing. Haplotypes were assigned based on family studies and gene frequencies were calculated using a subset of less related subjects selected from the genealogy. No rare class III variants were observed, but the characteristic low HLA diversity of isolated Amerindians populations present also in the Bari extends to Bf and C4. Thus there were only 22 different haplotypes segregating in families when nine loci were considered. All of them except three carried Bf*S, C4A*3, C4B*1. The null allele C4A*Q0 reached a frequency of 0.147 and was predominantly present in A24 Cw7 B39 DRB1*0411 haplotypes. In contrast to what has been reported using HLA alleles or class I haplotype frequencies and other isolated South American tribes, genetic distance estimates based on A-Cw-B-DR haplotype frequencies show a closer relationship between the two linguistically but geographically distant Venezuelan tribes, the Bari and the Warao, as compared to two culturally different Brazilian populations. The information reported here will be useful for identifying ancestral haplotypes in native peoples of America, for population comparison, and for discussing the differential influence of MHC haplotype diversity and population survival when similar data on other Amerindian tribes becomes available.

Alleles↗
PubMed1995

[The role of low-molecular-weight heparin in unstable angina, acute myocardial infarction and post-elective percutaneous transluminal coronary angioplasty].

PURPOSE: To evaluate the clinical efficacy and safety of subcutaneous (SC) low molecular weight heparin (LMWH) compared to intravenous (IV) non fractioned heparin (NFH) in unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty. METHODS: From September/92 to April/94, 314 patients were randomized in two groups. Group I-- 154 patients treated with SC LMWH, using in the 1st phase SC LMWH with a dosage of 160 UaXa IC/kg/day (group IA--92 patients), and in the 2nd, a dosage of 320 UaXa IC/kg/day (group IB--62 patients). Group II--160 patients treated with IV NFH 100UI/kg (bolus), followed by 1000UI/h with adjusted dosage by activated partial thromboplastin time. RESULTS: There was not a statistically significant difference among the three groups in relation to cardiac events, hemorrhagic complications and deaths. CONCLUSION: The clinical efficacy and safety of SC LMWH in patients with unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty were similar to IV NFH with the dosages used in this study.

Angina, Unstable↗
PubMed1987

Reversing the detrimental effect of adriamycin on skin grafts in rats.

We evaluated in a rat model the effects of a homologous fibrin glue in reversing the effects of Adriamycin on adherence and take of skin grafts. A total of 40 male Fisher rats were used in the study. During the first phase of the experiment, the animals were assigned to either group I (N = 10) receiving normal saline or group II (N = 10) receiving 6 mg/kg Adriamycin by tail vein injection 24 hours before surgery. Skin grafts with and without fibrin glue were placed over wounds in the backs of the animals and adherence was measured at 24 and 48 hours. In the second phase (N = 20), the experiment was repeated, this time evaluating the total area of skin graft take at 7 days. Fibrin glue was found to increase adherence and take of skin grafts in all Adriamycin-treated animals.

Animals↗
PubMed1982

Immunology of human gastric cancer: a preliminary report.

The immunological spectrum in fifteen patients with gastric cancer is presented. Patients were divided in three groups. Those with nonadvanced cancer, those with advanced but resectable lesions and those with advanced but nonresectable tumors. Preoperatively, elevated levels of circulating immune complexes (CIC) associated with hyporesponsiveness to phytohemagglutinin (PHA) and in mixed lymphocyte culture (MLC) as well as a positive leukocyte inhibitory serum factor (LIF-S) were found in nearly half of the patients. Inhibitory or enhancing autologous serum factors were detected. Postoperatively, immunologic parameters return to normal in patients with nonadvanced cancer, while in advanced cancer, antibody and cell-mediated immune response remained altered, with some changes associated with chemotherapy. These findings are probably related with the presence or absence of tumor and offer a distinct approach in evaluating the immunologic response of a tumor-bearing patient.

Adult↗
PubMed1982

[Bullous dermatomyositis].

The authors present a case of bullous dermatitis with clinical and biological polymyositis. The cause of the blisters can be found in an intense oedema of the superficial and middle dermis and is favoured by liquefaction of the basal layer and fibrinoid degeneration of the superficial dermis. It is diagnosed as dermatomyositis with malignancy even though it has been impossible to confirm the nature of the tumor. The diagnosis is being argued with other diseases that occasionally are vesiculobullous.

Aged↗
PubMed1976

The pathology of the joint tissues and its clinical relevance in prosthesis failure.

Thirty-four hip and knee total arthroplasty failures due to infection, loosening, intractable pain and dislocation were examined for synovial and capsular tissue debris. Simiquantitative assessments were made for metal polyethylene, acrylic and cellular debris and inflammation. The most important finding was that in the amounts normally shed into joints, debris particles do not appear to stimulate a polymorphonuclear response. The magnitude of this response correlates best with clinical and/or bacteriological evidence of infection. The quantity of acrylic particles could be correlated with clinical evidence of loosening. Since the correlation between infection and polymorphonuclear leukocytes, debris particles, and the reasons for failure is high, frozen section may aid the surgeon in determining the methods and timing of revision operations.

Acrylates↗
PubMedDate not supplied

Circadian variation in the frequency of myocardial infarction and death associated with acute pulmonary edema.

The records of 103 patients hospitalized for acute pulmonary edema were reviewed to determine the relationship between short-term outcome and time of presentation to the emergency department. Although only 17% of the patients arrived in the emergency department during the early afternoon hours, half of the deaths in the study occurred in this group. Patients presenting between noon and four PM had a significantly higher incidence of acute myocardial infarction (76% v. 28%, p = 0.03) and death (47% v. 9% p = 0.03) compared with patients presenting at other times. Differences in the pathophysiology of daytime versus nocturnal acute pulmonary edema may account for some of the variation in outcome.

Adult↗
PubMedDate not supplied

[Esophageal lesions caused by human papillomaviruses (HPV)].

Twenty two patients are presented with histologic lesions on esophageal biopsy compatible with infection by human papillomavirus. Symptoms were uncharacteristic, there was no sex difference and the mean age was 40 years. Upper GI endoscopy showed the following: a) multiple ulcers in the middle esophagus, most of less than 10 mm in diameter, rounded or oval in shape, separated by normal appearing mucosa, well delimited erythematous margins, with a smooth white base; b) In five patients, multiple white elevated lesions were found in the middle esophagus, separated by normal appearing mucosa. One patient had 2 papillomas; c) In two cases there was an epidermoid carcinoma at 25 and 28 cm from the dental arcade. Biopsy taken at the border of the lesions were compatible with papilloma virus infection. The possible relation of the lesions with papillomavirus infection was established only on histologic criteria. The described lesions regress without treatment or with nonspecific treatment, some cases of our series have responded to empiric antiviral medication.

Adult↗