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Biomedical subjects

J Barrera

Publications and source records attributed to J Barrera.

11 recordsLinked to original sources
PubMed2001

PEAZ-1: a new human prostate neoplastic epithelial cell line.

BACKGROUND: The generation of prostatic cell lines provides in vitro models for experimental studies of the pathogenesis of prostate carcinoma. Therefore, we established and characterized a new human prostate epithelial cell line, PEAZ-1 (prostate epithelial Arizona-1). METHODS: The PEAZ-1 cells were grown from a primary human prostate carcinoma specimen obtained from radical prostatectomy. The isolated cells were characterized by immunobiochemistry, immunohistochemistry, and tumorigenicity studies. RESULTS: PEAZ-1 cells are near diploid, tumorigenic, and androgen independent for cell growth. PEAZ-1 cells express N-cadherin, alpha- and beta-catenins, and p120 at cell-cell contacts, cytoplasmic laminin 5, vinculin, paxillin, and phosphotyrosine at focal adhesions, vimentin, and cytokeratins 8 and 18. They do not express plakoglobin, E-cadherin, and PSA, and do not form desmosomes and hemidesomomes. PEAZ-1 respond to ocadaic acid, a pro-apoptotic agent, by expression of p53. CONCLUSIONS: PEAZ-1 cells is a human prostate cancer cell line that has a number of mesenchymal characteristics.

Androgens↗
PubMed2001

Laminin-5-mediated gene expression in human prostate carcinoma cells.

Interactions between extracellular matrix (ECM) proteins and prostate carcinoma cells provide a dynamic model of prostate tumor progression. Previous work in our laboratory showed that laminin-5, an important member of a family of ECM glycoproteins expressed in the basal lamina, is lost in prostate carcinoma. Moreover, we showed that the receptor for laminin-5, the alpha6beta4 integrin, is altered in prostate tumors. However, the genes that laminin-5 potentially regulates and the significance of its loss of expression in prostate cancer are not known. We selected cDNA microarray as a comprehensive and systematic method for surveying and examining gene expression induced by laminin-5. To establish a definitive role for laminin-5 in prostate tumor progression and understand the significance of its loss of expression, we used a cDNA microarray containing 5289 human genes to detect perturbations of gene expression when DU145 prostate carcinoma cells interacted with purified laminin-5 after 0.5, 6, and 24 h. Triplicate experiments showed modulations of four, 61, and 14 genes at 0.5, 6, and 24 h, respectively. Genes associated with signal transduction, cell adhesion, the cell cycle, and cell structure were identified and validated by northern blot analysis. Protein expression was further assessed by immunohistochemistry. Mol. Carcinog. 30:119-129, 2001.

Blotting, Northern↗
PubMed1998

Maxillary distraction: aesthetic and functional benefits in cleft lip-palate and prognathic patients during mixed dentition.

In the last few years, distraction techniques have been used successfully to correct the hypoplastic human mandible. In patients with cleft lip and palate, normal growth of the maxilla may be impaired by early cleft repair, and many of them do not respond to orthodontic procedures alone. Maxillary distraction is an alternative technique to correct maxillary hypoplasia during mixed dentition. In the last 3 years, the procedure was performed in 38 patients aged between 6 and 12 years; 18 patients had unilateral cleft lip and palate, 9 patients had bilateral cleft lip and palate, 7 patients had unilateral cleft palate, 2 patients had prognathism, and 2 patients had nasomaxillary dysplasia. Photographs, posteroanterior and lateral cephalograms, and dental models are obtained preoperatively (as well as an orthopantomogram) to locate the tooth buds. A subperiosteal dissection is performed exposing the anterior and lateral aspects of the maxilla, and an incomplete horizontal osteotomy is done above the tooth buds. Using a facial mask and an intraoral fixed appliance system as an anchorage, we initiate on the fifth postoperative day the application of distraction forces. Maxillary advancement between 4 and 12 mm is achieved during 3 to 4 weeks, and a satisfactory class I or II molar relationship is also obtained. A combination of forward and downward distraction forces can be used to achieve simultaneous advancement and elongation of the hypoplasic maxilla. The aesthetic results are excellent, and the nasolabial angle is increased, including a more anterior projection of the upper lip. Nasal breathing is improved as well as the air flow and patency of the nasal airway. Velopharyngeal function remains unchanged after the procedure. The follow-up in this series varied from 6 months to 3 years. No relapses have been observed.

Child↗
PubMed1995

Serotonergic potentiation of photic phase shifts of the circadian activity rhythm.

Recent evidence suggests that serotonin may function to regulate the sensitivity of the circadian clock to the resetting effect of environmental light. Here we report that systemic administration of NAN-190, a drug that acts at both postsynaptic and somatodendritic serotonin receptors, potentiates light-induced phase shifts by as much as 250%. The effects of the drug are dose-related and are significant at light intensities between 0.2 and 200 lux. It is proposed that drugs with pharmacological properties similar to NAN-190 may prove useful as chronobiologics to adjust the sensitivity of the circadian system to natural 'zeitgebers'.

Animals↗
PubMed1987

Anorexia elicited by different catecholamines in rats.

Adrenaline (A) produces a strong anorexic effect, possibly by acting on hepatic receptors (nerve endings on hepatocytes). To study whether this is mediated by alpha- or beta-adrenergic mechanisms, or both, the anorexigenic effects of intraperitoneal injections of A, noradrenaline (NA) and isoproterenol (I) were studied under four different experimental conditions: (I) at the beginning of the dark period in rats fed ad libitum, or (II) on a 24 h-feeding/24 h-fasting schedule; (III) during the light period, under the same feeding schedule; (IV) after an acute 24 h fast. In condition I, the three catecholamines produced a marked decrease in feeding, slightly larger for A. In condition II (dark), they elicited a decrease in food intake about double that in condition III (light), their relative potencies also differed: A greater than I greater than NA in II and A greater than I = NA in III. In IV, the same relative potencies were obtained as in III. A mixture of half-doses of NA and I had the same effect in III and IV as either NA or I alone, suggesting that the alpha and beta effects are additive. However, even a mixture of the full doses of NA and I was not as effective as A in condition IV. This suggests that A is more potent than NA or I at stimulating hepatic adrenergic receptors that cannot be classified as either alpha or beta.

Animals↗
PubMed1987

Two factors associated with increased uptake of calcium in platelets from essential hypertensive patients.

The relative rate of calcium transport into platelets from essential hypertensive patients and healthy normotensive donors was measured using the metallochromic indicator arsenazo III and recording net decrease in optical density per 5 minutes (O.D.U./5 min). When platelets from essential hypertensive patients were suspended in the patient's own serum, calcium was transported more rapidly than when suspended in normal sera (0.0166 vs 0.0113 O.D.U./5 min, P less than 0.01) indicating that the difference is due to a circulating factor. When platelets from healthy normotensive volunteers were suspended in the donor's own serum or in a pool of normal sera, the relative rate of transport was lower than in the case of platelets from hypertensives suspended in the pool of normal sera (0.005 vs 0.0113 O.D.U./5 min, P less than 0.01) which suggests a membrane alteration rendering the platelets from hypertensives more permeable to calcium. It was observed that the increase of calcium entry was inhibited by verapamil. The nature of these circulating and membrane-associated factors is at present unknown, but the circulating factor was capable of increasing the membrane permeability to calcium in normal human platelets (from 0.0057 to 0.011 O.D.U./5 min, P less than 0.01) and even in rat liver mitochondria, an effect that was inhibited by ruthenium red.

Adult↗
PubMed1985

Degranulatory action of estradiol on blood eosinophil leukocytes in vivo and in vitro.

The degranulatory activity of estradiol was tested on blood eosinophil leukocytes in vivo and in vitro. Treatment of adult ovariectomized rats with 30 micrograms estradiol/100 g body wt. increased the percentage of degranulated eosinophils from 10% to about 70% at 6 or 24 h after treatment, and increased the rate of in vitro eosinophil degranulation of those eosinophils that were non-degranulated at the time of blood sample collection. The addition of estradiol to blood samples from untreated ovariectomized rats (0.05 micrograms/ml) increased the percentage of eosinophils degranulated in vitro at 1 h of incubation from 20% to near 60%. It is suggested that estrogen acts directly on the eosinophils, probably via specific hormone receptors. Considering the hypothesis that eosinophils are involved in the mediation of a group of responses to estrogen in the uterus, it is proposed that the hormone-induced degranulation of these cells may have physiological implications in the regulation of the intensity and duration of the eosinophil-mediated responses. In addition, estrogen-induced eosinophil degranulation may interfere with the action of eosinophils that have migrated to other target organs (lymphoid organs, etc.) under the action of other agents (glucocorticoid hormones, histamine, etc.) or conditions (immune reactions, etc.).

Animals↗
PubMedDate not supplied

[Molecular characterization of rotavirus in the city of Santafé de Bogotá, Colombia. Determination of the electrophenotypes and typing of a strain by RT-PCR].

131 diarrheic samples obtained from children taken to the emergency room of the Misericordia Hospital in Santafé de Bogotá were cultivated for rotavirus. These virus were found to be etiological agents for the diarrhea in 42 (32%) of the patients. In order to characterize electrophoretically the rotavirus they were cultured in cell line MA-104, total RNA was extracted and subjected to electrophoresis in SDS-PAGE and then the retrotranscription polymerase chain reaction. Eight different electrophoretic patterns were found. All patterns correspond to group A. Eight positive PAGE samples and the control type RRV were cultured in cell line MA-104. Viral growth was found only in the control and four of the samples. Total RNA was extracted from all five infected cultures and gene 9, which codifies for protein VP7 was amplified. All four samples and the control were shown to be G3. The finding of eight different electrophoretic types, all of them belonging to group A, show a diversity in co-circulating rotavirus strains. These findings contribute to a better understanding of viral acute gastroenteritis natural history and should help in developing new epidemiological vigilance strategies, prevention and control of rotavirus in children population of Santafé de Bogotá.

Cell Line↗