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Biomedical subjects

M Quintero

Publications and source records attributed to M Quintero.

At least 37 records · Page 2Linked to original sources
PubMed1995

Clinical experience with balanced reciprocal translocations.

Clinical experience with balanced reciprocal translocations: In order to evaluate past experience with respect to the occurrence of balanced reciprocal translocations (BRT) in patients with malformation syndromes and/or mental retardation (MS/MR) and in couples with reproductive failure, 4,335 karyotypes from the Genetics Unit of the Universidad del Zulia from January 1971 to December 1994 were reviewed, resulting in the identification of 15 cases of BRT (0.34%). All BRT were classic (CT) according to the number of breakpoints. In 66.6% of the cases, the indication for chromosome analysis was a MS/MR; 20% reproductive failure and, in 13.3% the BRT was a fortuitous finding. BRT were of familial origin in 6/15 (40%), 3/15 (20%) were de novo and the other 6/15 (40%) were of unknown origin. It was concluded that BRT can affect the phenotype, particularly when the request for the karyotype is motivated by MS/MR, and that genetic counseling in individuals at risk to be carrier is indicated.

Abnormalities, Multiple↗
PubMed1991

[Monoclonal antibodies and T-cell clones against HLA antigens: production and characterization].

The production and characterization of 21 monoclonal antibodies (MoAbs) resulting from the immunization of Balb/c mice with human lymphoblastoid cell lines is reported. Twelve MoAbs seem to be detecting an HLA polymorphic determinant. Four MoAbs are recognizing monomorphic Class I molecules and another MoAb detects HLA Class II molecules. These results were confirmed by ELISA, cytotoxicity, immunofluorescence and immunoprecipitation. Class and subclass of the MoAbs were assessed by Ouchterlony analysis. Twenty two T cell clones were additionally generated by limiting dilution of lymphocytes stimulated by allogeneic peripheral blood lymphocytes on mixed lymphocyte cultures. Five of these clones were characterized, testing each one for its ability to proliferate in response to a panel of lymphoblastoid cell lines. It was found that they detect the HLA-A9, A23, A29-31, Bw62 and DR7 specificities respectively. These results indicate that the generation of cellular monoclonal reagents is apparently more productive than the generation of murine MoAbs specific for polymorphic variants of HLA antigens.

Animals↗
PubMed1990

Differential regulation of Na,K-ATPase alpha 1, alpha 2, and beta subunit mRNA and protein levels by thyroid hormone.

The purpose of this study was to determine the effect of thyroid status on the Na,K-ATPase alpha isoforms and beta in rat heart, skeletal muscle, kidney, and brain at the levels of mRNA, protein abundance, and enzymatic activity. Northern and dot-blot analysis of RNA (euthyroid, hypothyroid, and triiodothyronine-injected hypothyroids = hyperthyroids) and immunoblot analysis of protein (euthyroid and hypothyroid) revealed isoform-specific regulation of Na,K-ATPase by thyroid status in kidney, heart, and skeletal muscle and no regulation of sodium pump subunit levels in the brain. In general, in the transition from euthyroid to hypothyroid alpha 1 mRNA and protein levels are unchanged in kidney and skeletal muscle and slightly decreased in heart, while alpha 2 mRNA and protein are decreased significantly in heart and skeletal muscle. In hypothyroid heart and skeletal muscle, the decrease in alpha 2 protein levels was much greater than the decrease in alpha 2 mRNA levels relative to euthyroid indicating translational or post-translational regulation of alpha 2 protein abundance by triiodothyronine status in these tissues. The regulation of beta subunit by thyroid status is tissue-dependent. In hypothyroid kidney beta mRNA levels do not change, but immunodetectable beta protein levels decrease relative to euthyroid, and the decrease parallels the decrease in Na,K-ATPase activity. In hypothyroid heart and skeletal muscle beta mRNA levels decrease; beta protein decreases in heart and was not detected in the skeletal muscle. These findings demonstrate that the euthyroid levels of expression of alpha 1 in heart, alpha 2 in heart and skeletal muscle, and beta in kidney, heart, and skeletal muscle are dependent on the presence of thyroid hormone.

Animals↗
PubMed1989

[Results of autopsy examination of the knee cartilage of 120 patients dying in the hospital. II. The femoro-tibial joint].

The authors have studied the autopsy results of both tibio-femoral joints in 120 patients: 57 women and 63 men, 112 of whom were over the age of 50. The condylar and tibial cartilages were classified into 5 categories: no lesion (0); slight fissure (I); severe fissure (II); slight deep ulceration (III); large ulceration (in more than 25 p. cent of the cartilage surface) exposing the sub-chondral bone (IV). In 120 patients, the 4 condyles in 58 patients (43.8 p. cent) and both tibio-femoral joints in 51 patients (42.5 p. cent) did not present any degenerative lesions beyond stage I. Stage III and IV cartilaginous lesions are rare before the age of 50. Their frequency suddenly increases after the ages of 70 in women and 80 in men. 44 p. cent of women and 31 p. cent of men presented tibio-femoral cartilaginous lesions of stages II or IV in at least one knee; 15.8 p. cent of women and 4.7 p. cent of men presented tibio-femoral lesions, stage IV, in at least one knee. In 58 p. cent of stage III and IV knee lesions, the menisci were abnormal: atrophic or torn. A menisco-chondrocalcinosis was found in 50 knees (20.8 p. cent of knees) of 28 patients (23.3 p. cent of patients). After the age of 60, the cartilaginous lesions were more severe and more extended in knees with menisco-chondrocalcinosis).

Age Factors↗
PubMed1988

The prevalence of chondrocalcinosis in the human knee joint. An autopsy survey.

The prevalence of pathological calcifications in the menisci and articular cartilage of both knees was investigated macroscopically and radiologically in 130 consecutive autopsies. The mean age of the subjects was 72 +/- 13 years. Only 8 subjects were less than 50 years old. All had been admitted to hospital and no patient had a history of joint disorders. Half of the patients were male. Calcifications were found in 27 (20.7%) cases, all over 60 years of age. There were 15.4% males and 26.1% females affected. The incidence of intraarticular calcifications in females increased from 11.1-37.5% and in males from 20-29.4% for the 60-69 year age group and the over 80-year age group, respectively. One third of affected cases had only meniscal and 2/3 had both meniscal and chondral calcifications. Isolated meniscal calcifications were found more often in 1 and mixed meniscal and chondral calcifications were found in both knees. Severe destructive articular cartilage lesions were observed significantly more often in joints with intraarticular calcifications than in joints of age matched subjects without calcifications. Joints with calcifications showed little evidence of synovial inflammation. Similarly, no specific relationship was found between the presence of crystal and amyloid deposits in the knees examined.

Aged↗
PubMed1987

[Results of autopsy examination of knee cartilage in 120 patients dying in the hospital. I. Femoro-patellar joint].

The authors have performed the pathological examination of the knees of 57 women and 63 men or 112 patients over the age of 50, who died in the hospital. The lesions of the patellar and trochlear cartilages were studied and classified according to four categories: stage I: non extended fissures; stage II: fissures extending over 25 p. cent of the articular surface; stage III: fissures associated with small deep ulcerations of the cartilage; stage IV: deeps and extended ulcerations of the articular cartilage exposing the sub-chondral bone. Cartilage alterations were found in 93.3 p. cent of the patellas; 26.2 p. cent of stage I; 22.5 p. cent of stage II, 27.1 p. cent of stage III; 17.5 p. cent of stage IV. These alterations are bilateral and symmetrical, most of the time. Their frequency and severity increase with age. Thus, deep and extended ulcerations (stage IV) of the patellar cartilage have a frequency of 1.9 p. cent before the age of 60.8 p. cent between 60 and 70 years, 13.6 p. cent between 70 and 80 years and 38.9 p. cent after 80 years. Alterations of the patellar cartilage are more frequent and more severe in women than in men. In 85.7 of the patellas they occupy both facets, overriding the patellar crest; more seldom, they are exclusively localized to the medial patellar facet (11.6 p. cent) or lateral facet (3.1 p. cent). Alterations of the trochlear cartilage, although more common are less frequent than that of the patellar cartilages. Patellar osteophytosis is very frequent.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Amyloid deposits in human knee and hip joints.

A systematic search for articular amyloidosis was carried out on both knees of 53 autopsy cases and on 26 femoral heads resected during surgery for hip prosthesis. Typical amyloid deposits exhibiting green apple birefringence following Congo red staining and thioflavin T fluorescence were found in 58.5% and 29% of the cases, in the knee and hip joint respectively. They occurred more frequently in articular cartilage than in the synovium, and in elderly subjects more than young ones. In the knee joint, the osteoarthritic changes and to a minor extent synovial inflammation appear to be positively correlated for the presence of intraarticular amyloid deposits. Such a correlation was not observed for the presence of calcium pyrophosphate dihydrate crystal deposits.

Aged↗
PubMed1985

Choroid plexus papilloma containing bone.

The presence of bone in choroid plexus papillomas is a rare event. The authors report a case of choroid plexus papilloma of the IVth ventricle containing bone in a 18-year-old man, and review two previously reported cases, as well as the mechanisms proposed for the presence of bone and cartilage in neuroepithelial neoplasms.

Adolescent↗
PubMed1985

Definition of DW8.2 by primary and secondary mixed lymphocyte cultures.

Using HLA-DW8 homozygous typing cells (HTC) of different ethnic origin it is possible to identify three subgroups of the DW8/DRW8 product (Mickelson et al., 1983). To further characterize the DW8.2 subgroup defined by HTCs of Amerindian origin we have now generated bulk PLTs within members of one extended Amerindian family and within selected HTCs of Caucasian, Oriental, and Amerindian origin. A panel of 61 DRW8 positive and negative donors of the three ethnic groups was used to test 15 different PLTs. Our results demonstrate that it is possible to generate DW8.1, 8.2, or 8.3 sensitized lymphocytes which distinguish in secondary cultures between each of the three subgroups of the DW8/DRW8 products. Of 40 DRW8 cells tested, 100% Caucasians typed as DW8.1, 100% Amerindians were 8.2; 75% Orientals were DW8.3; 8.3% were DW8.2, and 16.6% could not be classified within any of these subgroups. DRW8 individuals of mixed ethnic origin typed as either DW8.1 or DW8.2 and one DRW8 homozygous donor behaved as heterozygous 8.1/8.2. These results confirm the subdivision of the DW8/DRW8 product and explain the poor correlation and unexpected responses reported in MLC with DW8 HTCs and DRW8 donors of different ethnic origin.

Asian People↗
PubMed1984

Lipid peroxides in human articular cartilage.

The hypothesis that increased generation of lipid peroxides (LP) causes articular cartilage damage in older patients and in those with osteoarthritis was tested by directly measuring LP tissue levels in various layers of human articular cartilage. The LP content was significantly greater in the superficial than in the deeper portion of the cartilage, but lower in cartilage than in liver, kidney, adrenal glands and synovium. When LP were related to the total lipid content of these tissues, a high peroxide per lipid ratio was obtained for articular cartilage. The relevance of these findings to the mechanism of cartilage fibrillation is discussed.

Adrenal Glands↗
PubMed1984

[Cellular aspects of the aging of the articular cartilage. II. Condylar cartilage with fissured surface taken from normal and arthritic knees].

The authors studied the cellular density (number of cells per mm2) of cartilage taken from the femoral condyles of 46 cadavers (73 knees). In each case, the cartilage was taken from the summit of the condyle and, in 46 joints (27 subjects), a sample was also taken from the posterior surface (non weight-bearing zones). The fragments of non-calcified cartilage were sectioned with a cryostat and the sections (10 micrometers) were stained with hematein-eosin and solid red-Alcian blue. This study demonstrates: 1) a decrease in the cellular density of fissured cartilage compared to normal cartilage; this decrease appears to be proportional to the degree of fibrillation; 2) a decrease in the cellular density of apparently normal cartilage from arthrotic joints compared with normal cartilage from healthy joints; 3) with the age of the subjects, an increase in the density of the clones (number of clones per mm2) and the density of clonal cells (number of clonal cells per mm2) together with a decrease in the mean number of chondrocytes per clone. In fissured cartilage, the density of the clones, the density of the clonal cells and the number of chondrocytes per clone are slightly higher on the posterior surface of the condyles than on the summit of the condyles. These results emphasise the importance of the role that might be played by cellular phenomena in the mechanisms of deterioration of cartilage with aging and with arthrosis.

Adult↗
PubMed1983

Cell density of adult human femoral condylar articular cartilage. Joints with normal and fibrillated surfaces.

Cell and clonal density, lacunar and clonal diameters, and mean number of cells per single clone were studied in human femoral condylar cartilage of normal and osteoarthrotic joints. The values were related to the age of the subjects, the sampling site within the joints, and the depth from the articular surface. Cell density in every zone of both normal and diseased tissue decreased with increasing distance from the surface and increasing age. Cell density was significantly lower in age-matched osteoarthritic articular cartilage with an intact surface than in that of normal joints. The age-related decrease in the cell density accompanied an increase in the density of empty lacunae. The density of Alcian blue-stained cells, which actively synthesize proteoglycans as demonstrated by histoautoradiography, diminished with advancing age in all zones of articular cartilage. The percentage of these cells consistently decreased in the superficial and increased in the deep layers of the tissue in both normal and osteoarthritic joints. The clonal density was higher in the nonweight-bearing than in weight-bearing areas, and it increased with age, whereas the mean clone diameter and clonal cell number decreased.

Adult↗
PubMed1982

[Anatomic incidence of meniscochondrocalcinosis of the knee].

The authors have studied the incidence of menisco-calcinosis (MC) and that of menisco-chondrocalcinosis (MCC) of knee joints of 108 non selected cadavera. The mean age of the subjects was 71.8 +/- 13.8 years. The study was performed by radiographic examination of the menisci and cartilagineous fragments of femoral condyles using high contrast films. The incidence of MC or MCC was found to be 18.5 per cent. It was slightly higher in females (21.5 p. cent) than in males (15.8 p. cent) subjects but this difference failed to reach the level of statistical significance. No positive case was detected before the age of 60 years. For the age groups of: 60-69, 70-79, 80-89 and over 90 years, its incidence was: 11.7; 26.9; 21.2 and 50 (4 subjects out of 8) per cent respectively. Approximately 40 per cent of all positive cases had meniscocalcinosis without associated chondrocalcinosis. No single case of chondrocalcinosis without meniscocalcinosis was observed. Six out of 8 cases with MC calcinosis and 2 out of 12 cases with MCC were unilateral. The external menisci were more frequently and more heavily affected than internal ones. Eighty per cent of the knees affected by either MC or MCC were at the same time associated to an osteoarthrotic lesion compared to 35 p. cent of the knees without MC or MCC matched for age: a result which appeared to be highly significant difference.

Aged↗
PubMed1981

Deficiency of malic enzyme: a possible marker for malignancy in lymphoid cells.

Soluble malic enzyme (MEs) has been examined in long-term human lymphoid cell lines cultured from 101 individuals. In 65 out of 66 lines derived from people without lymphoreticular malignancy the enzyme was very active. Lines established from 35 individuals with various forms of lymphoreticular malignancy were also examined, including in some cases more than 1 line derived from the same patient. In all cases where the cell line was thought to be derived from normal cells MEs was active, but in 27 out of 29 lines thought to be derived from malignant cells (from 25 patients) MEs was not detected. In the case of two patients with chronic lymphatic leukaemia 'normal' lines active for malic enzyme, and 'leukaemic' lines lacking malic enzyme, had been cultured from the same individual. Preliminary investigations of the lack of malic enzyme in somatic cell hybrids derived from lymphoma and leukaemia cell lines are compatible with an alteration at the level of the structural locus MEs on chromosome 6. However, the restoration of MEs activity in one line by fusion with mouse teratocarcinoma cells suggests that the alteration may be of a regulatory nature.

Animals↗