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Biomedical subjects

A Rosado

Publications and source records attributed to A Rosado.

At least 109 records · Page 6Linked to original sources
PubMed1976

Changes in the protein conformation of human spermatozoal membranes after treatment with cyclic adenosine 3':5'-monophosphate and human follicular fluid.

Infrared spectra in the amide I and amide II regions of acrosomal membranes isolated from ejaculated human spermatozoa indicate the presence of a high proportion of the constitutive proteins in the most stable protein configuration, the antiparallel beta-conformation. Since the infrared spectra obtained with the membranes suspended in D2O or after extraction of the lipid components do not show any significant change, it can be postulated that the antiparallel pleated sheet conformation of human spermatozoal membrane proteins is independent of the hydrated state and of the lipid constitution of the membrane.

Acrosome↗
PubMed1976

Participation of membrane sulfhydryl groups in the epididymal maturation of human and rabbit spermatozoa.

Changes in the concentration of -SH groups on the human and rabbit spermatozoal membrane and during epididymal maturation were studied by means of a new fluorescent probe, carboxyphenylmaleimide (CPhM), which reacts specifically with -SH groups. Binding of CPhM did not modify oxygen uptake, motility, or viability of the sperm cells used, but produced a characteristic increase in fluorescence. By analysis of this increase it was possible to calculate the presence of 35 +/- 4.2 and 55 +/- 8 nmoles of exposed -SH groups/10(8) rabbit and human ejaculated spermatozoa, respectively. Caput epididymal cells bound significantly more CPhM than did cauda epididymal cells or ejaculated spermatozoa (155 +/- 22, 78 +/- 11, and 35 +/- 4.2 nmoles/10(8) cells, respectively, in rabbit cells; and 184, 110 +/- 18, and 55 +/- 8 nmoles/10(8) cells, respectively, in humans cells). In addition to the differences in number of exposed -SH groups observed between human and rabbit sperm cells, the behavior of these membrane-reactive groups when ethylenediaminetetraacetate and/or zinc were added to the incubation media indicates that the participation of membrane--SH groups in sperm physiology is species-specific.

Animals↗
PubMed1976

Amino acid pools in the feto-maternal system.

The determinations of the amino acid pools, including tryptophan (by fluorescence spectrometry), in the arterial and venous blood of the mother, the arterial and venous blood of the fetus (cord blood), the amniotic fluid and the placenta was done in eight women at the moment of delivery. Only nine amino acids (asp, try, met, phe, ser, cys, lys, gly, thr) were significantly retained and four (arg, glu, pro and glu-NH2) were significantly released by the fetal tissues. In contrast with this behavior most amino acids were retained by the maternal tissue, try, phe and hist showing the highest retention. When the amino acids are grouped as essential and nonessentials, the maternal tissues retained both categories without apparent discrimination, while the fetal tissues retained essential amino acids preferentially. Our results emphasize the importance of the placenta as the regulating system of the fetal milieu under normal conditions. Thus human fetal blood levels of amino acids are patterned after the placental ones and not after the maternal values obtained at the same time. It is apparent that the placenta seems to function as a nonspecific retention filter for outgoing amino acids, but that its function is selective in respect to the release of amino acids into the fetal circulation.

Amino Acids↗
PubMed1975

Effect of intrauterine copper on the nucleic acids, polysome pattern, and glycoprotein composition of the human endometrium.

The modifications induced by the intrauterine release of copper in the macromolecular and glycoprotein composition of the proliferative and secretory human endometrium were studied. In addition, the endometrial changes produced in women users of copper-T intrauterine devices in the polysome pattern and in the content of ribonucleoprotein particles were determined during the secretory phase. A group of ten untreated normal women (control group) and 15 users of 200 mm.-2 copper-T intrauterine device were selected for this study from the outpatient clinic of the Hospital de Ginecologia y Obstetricia No. 2 del Instituto Mexicano del Seguro Social. The main changes observed in the copper-T users were: a significant decrease in the endometrial content of RNA in both phases of the menstrual cycle, a significant decrease in protein in the secretory phase, and drastic changes in the fucose-sialic acid ratios, which decreased during the proliferative and increased during the secretory phases. Normal human secretory endometrium contained 4.89 plus os minus 0.28 (mean plus or minus standard error (S. E.) mg. ribonucleoprotein particle per gram wet weight, while the endometrium of the Cu-T users showed a significant decrease to 2.52 plus or minus 0.17 (mean plus or minus S. E.). In addition, the Cu-T induced a decrease in the heavy components of the polysome pattern with a concomitant increase in the lighter components.

Adult↗
PubMed1975

Comparative glycolytic metabolism of sperm from normal, asthenospermic, and oligoasthenospermic men.

The glycolysis of spermatozoa from normal, asthenospermic, and oligoasthen ospermic men was studied using a respirometry technique to measure glucose utilization by the production of 14CO2 from glucose 14C (U-L). Lactate and pyruvate were measured by a spectrophotometric method using DNA as reference. Human spermatozoa preferred glucose to fructose as the glycolytic substrate when concentrations of these hexoses did not exceed normal concentrations in the blood. Spermatozoa from oligoasthenospermic men produced an average of 3.5 times more 14CO2 (345, 457 dpm/mg DNA/hour) than did spermatozoa from asthenospermic (88,837 dpm/mg DNA/hour) and normal men (96,595 dpm/mg DNA/hour). They also formed four times more lactate (9.63 mumoles/mg DNA/hour) than spermatozoa from normal men (2.33 mumoles/mg DNA/hour) and 6.4 times more pyruvate (2.90 mumoles/mg DNA/hour compared to 0.45 mumoles/mg DNA/hour). Spermatozoa from asthenospermic men formed amounts of lactate (3.01 mumoles/mg DNA/hour) and pyruvate (0.63 mumoles/mg DNA/hour) similar to those produced by spermatozoa from normal men.

Carbon Dioxide↗
PubMed1975

Participation of vitamin A in the maturation of rabbit spermatozoa.

Vitamin A concentration was fluorometrically measured in epididymal and ejaculated rabbit spermatozoa and in some of the sperm cells subcellular components. The concentration of vitamin A in the epididymal cells was about one-half that observed in the ejaculated spermatozoa (2.68 as against 1.05 mug/10(8) cells) and seemed to be the same in the sperms obtained from both the head and the tail of the epididymus. The concentration of vitamin A was also found to be significantly higher in the seminal plasma than in the epididymal secretion (0.06 as against 0.039 mug/mg protein respectively). Practically all the vitamin A was found in the fractions obtained by treatment with hypotonic MgCl2 (acrosomal region) and/or with hyamine and dithiothreitol (plasma membrane). It was concluded that the sudden increase in the sperm concentration of vitamin A that occurs upon ejaculation may be required for the stabilization of the acrosomal and plasma membranes.

Acrosome↗