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Biomedical subjects

R Peñaloza

Publications and source records attributed to R Peñaloza.

18 recordsLinked to original sources
PubMed2006

In vitro leukemic cell differentiation and WT1 gene expression.

Cell differentiation and four WT1 isoforms were assessed in CD34(+) cells from patients with acute myelogenous leukemia in presence or absence of recombinant human GM-CSF and G-CSF, on days 0, 10 and 20 of culture. We found that WT1 isoforms expression was consistently higher in AML-derived CD34+ cell-enriched cell fractions, as compared to their normal counterparts, and interestingly, in both cases, cells had differentiation towards the myeloid lineage with WT1 expression different patterns. This data suggest that WT1 expression seems to be modulated by the presence of cytokines, especially on day 20 of culture.

Antigens, CD34↗
PubMed2001

(AC)n dinucleotide repeat polymorphism in 5' beta-globin gene in native and Mestizo Mexican populations.

Repeated sequences are dispersed along the human genome. These sequences are useful as markers in diagnosis of inherited diseases, in forensic medicine, and in tracking the origin and evolution of human populations. The (AC)n repeated element is the most frequent in the human genome. In this paper, the (AC)n repeated element located in the 5' flanking region of the beta-globin gene was studied by single-strand conformation polymorphism (SSCP). Four ethnic Mexican groups (Mixteca, Nahua, Otomí, Purépecha) and a Mestizo population were analyzed. We observed three alleles, A [(AC)16, B [(AC)14], and C [(AC)18], with a frequency of between 68.2% and 86.9%, 13.1% and 18.2%, and 6.7% and 13.7%, respectively. Allele C was present only in Purépecha and Mestizo groups. The absence of this allele in the other ethnic groups studied suggests that there is low genetic admixture of Purépecha and that this is a relatively isolated population. However, it could be that the C allele occurs in low frequencies in the other groups as a result of small sample sizes. The (AC)n repeat polymorphism in the beta-globin gene has not been previously studied in Amerindian populations.

Alleles↗
PubMed1995

Molecular studies of Mendelian disorders, embryonic neoplasias, and polymorphisms in selected samples of the general population. A contribution to the genetic characterization of the Mexican population.

Molecular studies using polymerase chain reaction (PCR) and restriction enzymes, as well as intragenic STRs and newly designed primers, were performed in patients with Duchenne-Becker muscular dystrophy, sickle cell anemia, retinoblastoma, and nephroblastoma. The usefulness of these methodologies in the precise identification of mutational changes, in carrier detection and in the understanding of neoplastic transformations, as well as its applications in genetic counseling and prenatal diagnosis, are discussed. In addition, genetic polymorphisms in the beta globin gene cluster and in mtDNA were investigated. All these studies, the first performed in our population, contribute to establish the genetic origin and to a better characterization of the Mexican population.

Adolescent↗
PubMed1994

Red cell acid phosphatase types and GC polymorphisms in Mérida, Oaxaca, León, and Saltillo, Mexico.

Red cell acid phosphatase types and GC polymorphisms were studied in Mérida and Oaxaca, Mexico. GC polymorphisms were also investigated in León and Saltillo. The ACP*A, ACP*B, and ACP*C gene frequencies were 0.215, 0.770, and 0.015 respectively, in Mérida and 0.205, 0.788, and 0.002, respectively, in Oaxaca. In Oaxaca the ACP*R gene had a frequency of 0.005. The results are similar to other Mestizo groups studied in Mexico; it is concluded that the ACP*C and ACP*R genes were introduced by admixture of native Amerindians with whites and blacks, respectively. The GC*1S, GC*1F, and GC*2 gene frequencies were 0.489, 0.289 and 0.222, respectively, in León; 0.500, 0.272, and 0.228, respectively, in Mérida; 0.454, 0.337, and 0.209, respectively, in Oaxaca; and 0.505, 0.356, and 0.139, respectively, in Saltillo. These results are similar to what has been obtained in other Mestizo populations and Indian groups in Mexico, probably because the main ethnic component in both is Amerindian.

Acid Phosphatase↗
PubMed1993

Effects of chronic hypoxia and exercise on plasma erythropoietin in high-altitude residents.

The present study was performed to evaluate the effects of chronic inspiratory hypoxia and its combination with physical exercise on plasma erythropoietin concentration ([EPO]). Eight natives from the Bolivian Plateau were investigated at 3,600 m above sea level at rest as well as during and up to 48 h after exhaustive exercise (EE) and 60 min of submaximal (60%) cycle ergometer exercise (SE). Ten sea-level subjects were used as a control group for resting values. The mean resting plasma [EPO] of the high-altitude group (19.5 +/- 0.7 mU/ml) did not differ from that of the sea-level group (18.1 +/- 0.4 mU/ml) but was higher than would be expected from the relationship between [EPO] and hematocrit at sea level. Five hours after both types of exercise, [EPO] decreased by 2.1 +/- 0.8 (EE, P < 0.01) and 1.6 +/- 0.8 mU/ml (SE, P < 0.05); 48 h after SE, [EPO] increased by 2.6 +/- 0.9 mU/ml (P < 0.05). It is concluded that 1) high-altitude natives need relatively high [EPO] to maintain their high hematocrit and 2) exercise at low basal arterial PO2 does not directly increase plasma [EPO] in high-altitude residents but seems to exert suppressive effects.

Acclimatization↗
PubMed1979

Gc globulin and prealbumin serum levels in patients with cancer and benign inflammatory diseases and in asymptomatic smokers.

Gc globulin and prealbumin serum levels were determined in a coded serum panel from the National Cancer Institute-Mayo Clinic. Serum samples came from 100 patients with cancer (lung, prostate gland, or gastrointestinal tract), from 50 patients with benign inflammatory diseases from the same organs as those of the cancer patients, and from 50 clinically healthy smokers. No differences were observed among groups in the Gc globulin (vitamin D carrier) serum concentrations; however, prealbumin (vitamin A carrier) serum levels were decreased for patients with benign inflammatory diseases and for cancer patients; the cancer group showed the greatest decrease.

Alpha-Globulins↗
PubMed1978

Serum IgG and IgD and levels in some infectious and noninfectious diseases.

Serum IgG and IgD levels were determined in the following groups: professional blood donors, healthy smokers and patients with acute hepatitis, with acute salmonellosis, with hepatic cirrhosis, with cancer (prostate, lung and gastrointestinal tract) and with benign diseases of the same organs as the cancer patients. IgG was significantly increased in the groups of patients with hepatitis, hepatic cirrhosis and cancer. IgD values showed a wide dispersion in all the groups, which do not allow for comparisons among means. For that reason, linear regression analysis between IgG and IgD was done, the results being significant only in the two groups with infectious diseases (acute hepatitis and acute salmonellosis), which suggest that IgD could be involved in the immune response against their respective pathogenic agents.

Blood Donors↗
PubMed1978

Altered carbohydrate content of alpha1-antitrypsin in patients with cancer.

The glycosylation of IgG and alpha1-antitrypsin (alpha1-AT) was studied by their precipitation with concanavalin A in a codified serum panel from the National Cancer Institute (Bethesda, Md.) and the Mayo Clinic (Rochester, Minn.). The serum panel was composed of samples from 98 patients with cancer of the lung, prostate gland, or gastrointestinal tract, 50 samples from patients with benign inflammatory diseases from the same organs as those of the cancer patients, and 41 samples from apparently healthy smokers. The assay for alpha1-AT revealed statistically significant differences in levels between the patients with cancer, the patients with benign diseases, and the smokers. However, tests revealed no statistically significant difference in IgG levels among the three groups. These results suggest that cancer may alter the glycosylation of alpha1-AT. The possibility remains that the test for alpha1-AT can detect genetic differences among individuals, but studies of families are needed before a final conclusion can be made.

Adult↗
PubMedDate not supplied

[Medical pathology due to trinucleotide repeats].

Trinucleotide repeat expansion is responsible for ten human diseases described so far. Four types of repeats are involved in these expansions, with type, number and position in the gene varying from one disease to another. In some fragile sites, the trinucleotide repeat is found to be enlarged to 200 or more. Smaller expansions have been found within coding regions of some genes that are associated with neurodegenerative diseases, such as Huntington's disease. The continuous expansion of the trinucleotide repeats in subsequent generations explains the genetic anticipation, peculiar to these disorders. Recently, it was shown that two expanded minisatellite sequences are also involved in both progressive myoclonus epilepsy type 1 and distamycin A-sensitive fragile site, FRA16B. This form of peculiar heredity is very important because of its relationship with some of the common human degenerative diseases.

Chromosome Aberrations↗