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Biomedical subjects

A Zapata

Publications and source records attributed to A Zapata.

10 recordsLinked to original sources
PubMed1992

Building blocks for the synthesis of glycosyl-myo-inositols involved in the insulin intracellular signalling process.

Glycosylation of (+/- )-1-O-benzyl-2,3:5,6-di-O-isopropylidene-myo-inositol (4) with 6-O-acetyl-4-O-allyl-2-azido-3-O-benzyl-2-deoxy-beta-D-glucopyranosyl trichloroacetimidate (6) gave the 4-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)- myo-inositol derivative (9) as a mixture of diastereoisomers which could be resolved by chromatography. Likewise alpha-glycosylation of 4 with 6-O-acetyl-2-azido-3-O-benzoyl-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-beta- D- galactopyranosyl)-D-glucopyranosyl trichloroacetimidate (10) gave the corresponding pseudotrisaccharide derivative 16 as a mixture of diastereomers which could be resolved partially by chromatography. alpha-Glycosylation of enantiomerically pure 2,3:5,6- (18) and 2,3:4,5-di-O-isopropylidene-1-O-menthoxycarbonyl-myo-inositol (19) with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-D-glucopyranosyl trichloroacetimidate (20) gave the pseudodisaccharide derivatives 21 and 22, respectively. Likewise, alpha-glycosylation of 18 with 10 afforded a pseudotrisaccharide derivative (23).

Carbohydrate Sequence↗
PubMed1992

Infantile stimulation and the role of the benzodiazepine receptor system in adult acquisition of two-way avoidance behavior.

The present study shows that postnatal "consistent" handling (CH) of rats had long-lasting improving effects on coping with an stressful task (i.e. two-way active avoidance), and that such effects were partially prevented by acute Ro 15-1788 (antagonist of benzodiazepine receptor-BZR; 5 mg/kg) administration. Long-lasting detrimental effects in the same task were also observed in rats which received postnatal "inconsistent" handling (INCH), effects that were slightly increased by acute Ro 15-1788 treatment. Finally, Ro 15-1788 tended to increase avoidance acquisition in non-handled (NH) animals. The observed effects of Ro 15-1788 could be partially attributed to a differential modulation of the process of avoidance acquisition depending on postnatal treatments producing different levels of emotionality.

Adaptation, Psychological↗
PubMed1992

Reptilian thymus gland: an ultrastructural overview.

Like in higher vertebrates, the thymus gland of reptiles consists of lymphoid cells within epithelial framework and characteristic myoid cells. Mammalian-like Hassall's corpuscles are absent. Secretory cells, secretory and degenerative cysts as well as phagocytic cells, and plasma cells can be observed. Interdigitating cells and some characteristic features of thymic innervation and vascular system are also described in the reptilian thymus gland.

Animals↗
PubMed1979

Distribution of ventilation in normal children.

Measurements of closing volume and the distribution fo ventilation by both single-breath (SBN2) and multiple-breath nitrogen washout methods were obtained in 376 healthy boys and girls, ages 6 to 18 years. A closing volume could be demonstrated in 39 percent of the subjects, and closing volume expressed as percentage of vital capacity did not change with height. Closing capacity expressed as percentage of total lung capacity showed a slight decrease with height. The slope of phase III of the SBN2 curve decreased with height. Single compartment N2 washout curves were observed in 72 percent of the subjects, and the incidence of single compartment curves increased with age. In those subjects with two compartment N2 washout curves, the relative compartmental ventilation became more even with increasing height. Our observations suggest that parallel units among peripheral airways grow at different rates.

Adolescent↗
PubMed1978

Ultrastructure of the filiform papillae on the tongue of the hamster.

The fine structure of the filiform papillae on the hamster tongue is described level by level from the basal layer to the surface. We did not observe two distinct types of cells with different morphology or components which could be held responsible for the production of two different types of keratin as have been described in other animals, but rather a uniformity of cell structures in each layer and only the so-called "smooth" type of keratin. However, keratin granules were more abundant in the anterior part of the papilla.

Animals↗