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Biomedical subjects

A Sanchez

Publications and source records attributed to A Sanchez.

At least 235 records · Page 13Linked to original sources
PubMed1988

In vivo Junin virus-mouse macrophages interaction.

The role of mononuclear phagocytic cells in extraneural infection of the mouse with Junin virus (JV) was studied. Endpoint susceptibility (4 days of life) was evaluated by intraperitoneal (i.p.) inoculation of suckling mice. By means of immunofluorescence (IF) and C3 receptor assays, it was found that macrophages were permissive to viral replication in vivo and fostered the recruitment of inflammatory cells as evidenced by the absence of C3 marker. In support, in vitro infection failed to induce alterations of this receptor. Throughout, both in vivo and in vitro, there were no signs of C3-mediated phagocytosis. Silica treatment had no effect on either resistance or susceptibility, suggesting that the "macrophage-barrier" failed to hinder or favour the course of disease. Differences with other JV models are discussed.

Age Factors↗
PubMed1987

cAMP reduces the affinity of Ca2+-triggered secretion in platelets.

Prostacyclin and other related compounds known to increase intracellular cAMP levels inhibit platelet responses. The mechanisms involved are only partially known, especially those concerning the complex relations between Ca2+ and cAMP as opposite intracellular mediators. Here, we have investigated aggregation and secretion in quin2-loaded platelets under conditions in which Ca2+ and cAMP are the only intracellular mediators. Our results show that cAMP inhibits aggregation and secretion in ionophore-treated cell without modifying their intracellular Ca2+ levels. This result suggests that the inhibition takes place on some intracellular target for Ca2+.

Blood Platelets↗
PubMed1987

Adh expression in species of the mulleri subgroup of Drosophila.

The locus encoding the NAD-dependent alcohol dehydrogenase (alcohol:NAD oxidoreductase; EC 1.1.1.1) is duplicated in some species of the cactophilic mulleri subgroup of Drosophila. Here we report a survey on the expression throughout development and in different tissues for this system, its regulation using interspecific hybrids, and the effects induced by 2-propanol in 10 species belonging to four different clusters of the above-mentioned subgroup. Our results indicate different expression throughout development and in different tissues, cis regulation in hybrid ovaries, trans (-) regulation in hybrid adults, and different responses to 2-propanol.

1-Propanol↗
PubMed1987

Identification and analysis of Ebola virus messenger RNA.

Six messenger RNA species of Ebola virus were identified in infected Vero E6 cells. Virion RNA hybridizes to each of the mRNAs, confirming that Ebola virus possesses a negative-stranded RNA genome. The mRNAs are monocristronic transcripts, are synthesized in the presence of actinomycin D, and are polyadenylated. In vitro translation of mRNA preparations results in the synthesis of five authentic viral proteins and a putative unglycosylated form of the glycoprotein, demonstrated by immunoprecipitation with virus-specific antisera and SDS-PAGE. No mRNA species was detected for the polymerase (L protein) gene.

Animals↗
PubMed1987

Zinc, vitamin B-6, and other nutrients in pregnant women attending prenatal clinics in Mexico.

Biochemical measurements and 24-h dietary recalls were conducted early (18.9 +/- 5.9 wk) and late (35.1 +/- 2.0 wk) in pregnancy in women attending clinics in Montemorelos, Mexico. Mean weight gain per week (0.4 +/- 0.2 kg) and birth weight (3381 +/- 456 g) were normal. Intakes tended to decline during pregnancy and declined significantly for zinc (p less than 0.05) and vitamin B-6 (p less than 0.03). Mean Zn intake late in pregnancy was low (7.8 +/- 3.3 mg/d). Various supplements were taken but none contained Zn. During pregnancy mean plasma Zn levels fell (p less than 0.001) and late in pregnancy 57% of the women had values suggestive of poor Zn status (less than or equal to 8.1 mumol/L). These data indicate that Zn intakes of approximately 8 mg/d will not maintain plasma Zn levels in late pregnancy. Erythrocyte glutamic-pyruvic transaminase (EGPT) index and the index of diamine oxidase (DAO), a vitamin B-6-requiring enzyme of placental origin, were correlated suggesting that DAO index may be useful in evaluating vitamin B-6 status in pregnancy.

Adult↗
PubMed1987

Chemotherapy of advanced gastric carcinoma (stage IV): a randomized study of FAM versus 5-FU plus BCNU.

Forty-six patients with advanced gastric carcinoma (Stage IV) were evaluated in a prospective randomized comparison of two chemotherapy regimens (FAM versus 5-FU plus BCNU) to identify therapeutic activity. Treatment groups were well balanced with respect to known prognostic factors. Thirty-three patients had measurable disease and thirteen had only microscopic residual disease in the resection margins. The overall median survival of the entire group was 13.2 months. Two (6%) patients with measurable disease reached complete response (CR), 1 (3%) partial response (PR), 12 (36%) had stable disease (SD) and 18 (56%) had progressive disease (PD). The responders had not reached the median survival yet, the patients with SD had a median survival of 14.7 months and the PD 9.5 months. In the FAM arm there were 3 (18%) responders (2 CR and 1 PR), 7 (41%) SD and 7 (41%) PD, versus O responders, 5 (31%) SD and 11 (69%) PD in the 5-FU plus BCNU arm. In the FAM arm the median survival was 15.7 months versus 9.9 months in the other therapeutic arm. The statistical analysis indicated that survival associated with FAM regimen was superior to that reached with the 5-FU plus BCNU regimen. Thirteen patients with unmeasurable disease had a median survival of 15.9 months.

Adult↗
PubMed1987

A correlation and path coefficient analysis of components of calciuria in normal subjects and idiopathic stone formers.

The composition of 24 h urine samples collected by 50 normal controls and 76 stone formers (30 hypercalciurics, 13 hyperuricosurics and 33 patients without metabolic abnormalities) were studied. Statistically significant multiple regression equations were obtained between calciuria and the urinary excretions of sulfate, citrate, sodium and creatinine. The three former ions were selected as variables because they were assumed to affect the tubular fluid concentration of ionized calcium and interfere with the reabsorption of calcium. Urinary creatinine was included because it increased the statistical significance of the multiple regression equations; it is assumed to be a function of body size. The regression equations differed between both groups of subjects because stone formers excreted significantly more sulfate and less citrate than controls. The four factors considered (sulfate, citrate, sodium and creatinine) account for 28.3, 6.8, 7.3 and 26.4% of the total variation of calciuria of normal controls and 45.0, 2.6, 8.6 and 14.7%, respectively, for stone formers.

Adult↗
PubMed1986

Altered renal alpha-adrenoceptor regulation in DOCA-salt rats: chronic effects of alpha 1- and alpha 2-receptor blockers.

Effects on the alpha-adrenoceptor binding in the kidneys of DOCA-salt rats were examined after a 6 week treatment of once-daily injections of prazosin, a selective alpha 1-adrenoceptor blocker; yohimbine, a selective antagonist for alpha 2-adrenoceptors; and prazosin plus yohimbine. alpha 1-Receptor binding was decreased by prazosin, while alpha 2-receptor binding was increased by simultaneous administration of prazosin + yohimbine. Equilibrium dissociation constants (KD) for [3H]prazosin and [3H]yohimbine were not significantly different (between groups). Since these drugs can prevent the development of hypertension in DOCA-salt rats, the present data strongly suggests that selective alteration of alpha-receptor-mediated physiological responses is unrelated to decreased or increased binding site densities. The mechanism of hypertension prevention may involve changes in the coupling of receptors to postreceptor events.

Adrenergic alpha-Antagonists↗
PubMed1985

Ca2+-independent secretion is dependent on cytoplasmic ATP in human platelets.

The secretion evoked in human platelets by physiological agonists is an energy-requiring process that depends on the metabolic ATP pool. Diacylglycerol, phorbol ester and collagen evoke a secretory response, which is not associated with an increase of cell Ca2+ levels, and is attributed to activation of protein kinase C [(1983) Nature 305, 317-319]. The secretion evoked by these agonists decreased along with cytoplasmic ATP depletion in the same way that the thrombin-induced secretion did. The secretory response was restored by raising again the cytoplasmic ATP levels. These results support the idea that the secretory response takes place by the physiological ATP-dependent mechanisms rather than by membrane perturbations in these instances.

Adenosine Triphosphate↗
PubMed1985

Dithiocarbamates in heavy metal poisoning: complexes of N,N-di(2-hidroxyethyl)dithiocarbamate with Zn(II), Cd(II), Hg(II), CH3Hg(II), and C6H5Hg(II).

The complexes M(DHDC)2, CH3Hg(DHDC), and C6H5Hg(DHDC) (M = Zn, Cd, Hg; DHDC = N,N-di(2-hydroxyethyl)dithiocarbamate) were prepared and investigated in solution and in the solid state by using 1H and 13C NMR, ir, and Raman spectroscopy. The dithiocarbamate group is anisobidentate and the complexes are associated in solution and the solid state via hydrogen bonding. The possible relation of these structural properties to the behavior of DHDC in the treatment of cadmium poisoning is discussed.

Cadmium↗
PubMed1985

Seventh-Day Adventist vegetarians have a quiescent proliferative activity in colonic mucosa.

The proliferation of epithelial cells in colonic mucosa was studied in humans at varying degrees of risk for colon cancer. Seventh-Day Adventist vegetarians, known to have significantly lower mortality from colon cancer than the general U.S. population, had the most quiescent proliferative activity of mucosal epithelial cells. Increased replication and expansion of the proliferative compartment accompanied increased colon cancer risk. The analytical methods of this study may be useful in assessing the influence of dietary components involved in the initiation, promotion or inhibition of colon cancer, and in developing strategies for nutritional intervention.

Adult↗
PubMed1985

Chromosomal translocation 1/29 in Santa Gertrudis sires.

Chromosomal analysis of 38 Holstein, 10 Santa Gertrudis, and 5 Zebu sires revealed for the first time the occurrence of the Robertson translocation in this breed. The importance is stressed of cytogenetic studies for sires.

Animals↗
PubMed1984

Effects of prostaglandin I2 and forskolin on the secretion from platelets evoked at basal concentrations of cytoplasmic free calcium by thrombin, collagen, phorbol ester and exogenous diacylglycerol.

Cytoplasmic free calcium ([Ca2+]i) and secretion of ATP were measured in quin2-loaded human platelets. In certain conditions thrombin and collagen cause secretion while [Ca2+]i remains at basal concentrations, a response attributed to activation of protein kinase by diacylglycerol formed by hydrolysis of inositol lipids. This secretion evoked by thrombin could be totally suppressed by prostaglandin I2 or forskolin, as expected from the known ability of cyclic AMP to inhibit phospholipase C. The secretory response evoked by collagen at basal [Ca2+]i and that evoked by exogenous diacylglycerol or phorbol ester, direct activators of protein kinase-C, were much less affected by these inhibitors, suggesting that thrombin and collagen may promote formation of diacylglycerol by different mechanisms.

Blood Platelets↗