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Biomedical subjects

R Reyes

Publications and source records attributed to R Reyes.

At least 91 records · Page 5Linked to original sources
PubMed1986

Mode of entry of glycosaminoglycan sulfate during epididymal maturation of bull spermatozoa. I. Charge neutralization mechanism.

Heparin uptake by bull spermatozoa from each one of main epididymis regions was investigated to determine whether the heparin binding was modified during epididymal maturation, the heparin internalization differed during the maturation process, and the charge neutralization by histone or polylysine enhances heparin internalization. From our results we conclude that membrane binding of heparin is greater in the spermatozoa from the caput epididymis than in those of the cauda epididymis region (9.41 +/- 2.27 vs. 2.89 +/- 0.72 pmole of [3H]heparin) and that membrane binding of heparin occurs also at 4 degrees C (4.97 +/- 1.36 vs. 1.05 +/- 0.54 pmole of [3H]heparin). It was also clearly shown that heparin uptake requires active metabolism of the cell and that internalization decreases according to the progress of the epididymal maturation process [6.34 +/- 1.25 (caput) vs. 1.74 +/- 0.72 (cauda)]. Finally, charge neutralization of heparin by histone or polylysine did not enhance heparin internalization.

Animals↗
PubMed1985

The frequency and economic burden of genetic disease in a pediatric hospital in Mexico City.

A survey of 2,945 admissions to the National Institute of Pediatrics, México, was undertaken to document the frequency and burden of genetic disorders. Patients were classified into five categories: single gene disorders; chromosomal disorders; complex genetic etiology; unknown etiology, and nongenetic disorders. Of all admissions studied, 4.3% had a genetic disease (categories 1 and 2); 33.5% had a partly genetic condition (category 3); 13.8% had a disorder of unknown etiology; and 48.4% had an environmental disease. In terms of economic burden, patients with genetic or partly genetic disorders came more frequently from outside the city and had more and longer admissions with a higher number of surgeries. The results suggest that genetic disease, although less frequent than disease caused by environmental conditions, lays a considerable financial burden on the hospital and on the affected families. The need to create genetic units in developing countries is emphasized.

Child, Preschool↗
PubMed1985

Effect of divalent ions in acrosome reaction induced by glycosamineglycans in porcine spermatozoa.

Magnesium, calcium, and zinc at the concentration of 10 microM are capable of inducing a "true" acrosome reaction in the pig spermatozoa judged by the criteria of the fusion of the acrosome and the plasmatic membrane at the anterior region or the sperm nucleus. The optimal percent of acrosome reaction reached by any of the ions tested as a whole was 50%. When glycosamineglycan sulfate (GAGs) plus 10 microM of Mg++, Ca++, or Zn++ was added, they reach to 70-80% of acrosome reaction. At the electrom microscope, thin sections taken from pig spermatozoa treated with ions, GAGs, or ion + GAGs under optimal experimental conditions revealed the same pattern of acrosomal reaction. Results suggest the important role that divalent cations play in general in the induction of the acrosome reaction and question the so-called essential role of calcium ions.

Acrosome↗
PubMed1984

Osler's nodes, pseudoaneurysm formation, and sepsis complicating percutaneous radial artery cannulation.

Percutaneous arterial cannulation is useful for hemodynamic monitoring and frequent arterial blood gas determinations in selected intensive care patients. However, this procedure is not without risk. We report a case of localized Osler node formation, distal to a radial artery catheter, associated with sepsis, pseudoaneurysm formation, and thrombosis at the site of catheterization. Complications of this technique require aggressive medical and, in selected cases, surgical intervention.

Adult↗
PubMed1984

Glycosamineglycan sulfate as acrosomal reaction-inducing factor of follicular fluid.

Follicular fluid from different mammalian species possesses two factors responsible for the induction of capacitation: a sperm-stimulating factor and an acrosomal reaction-inducing factor. The glycosamineglycan-sulfate (GAGs) extracted from pig follicular fluid induce acrosome reaction in pig spermatozoa which exhibit no morphological difference between the GAGs-induced reaction and the natural one. Acrosomal reaction commenced 30 min after the addition of GAGs and depended on GAGs concentration reaching 80% of acrosomal reacted spermatozoa after 6 hr of incubation with 7 mg of GAGs/ml. Chemical composition differs with the chemical data that characterize them as proteoglycans since those we obtained were practically protein free (2%). Another difference resides in the uronic acid content, which is almost twofold higher (59%). Electron microscope observations of the acrosomal reacted spermatozoa revealed that the addition of 10 mg/ml of trypsin soybean inhibitor did not interfere with any of the acrosomal reaction steps. The active capacitating factors may also originate from the follicular fluid released into the genital tract during ovulation.

Acrosome↗
PubMed1984

Heparin-induced release of DNA template restrictions in human sperm zinc-depleted nuclei.

The addition of heparin to human sperm zinc-depleted nuclei releases DNA template restrictions. Spermatozoa depleted of zinc were assayed for (3H-methyl), thymidine incorporation was observed (27,500 +/- 1,248 dpm of 3H methyl-thymidine). Sperm cells incubated in the presence of 10 mg/ml of soybean trypsin inhibitor shows no effect in sperm nuclear swelling or in the release of DNA template restrictions. This process runs in a parallel fashion to the nuclear swelling induced by heparin, suggesting that swollen nuclei might be the source of DNA template. This was confirmed by autoradiographic studies, since all the sperm cells whose nuclei were judged swollen by morphological criteria also appeared labeled. The fact that there was no need for ATP generating system or of exogenous DNA polymerase emphasized the control role that zinc plays in the physiology of the human spermatozoa.

Cell Nucleus↗
PubMed1984

Capacitation of human spermatozoa by heparin.

Zona-free hamster oocytes were incubated in vitro with human spermatozoa treated with heparin for 5, 10, 20, and 30 min. Sperm penetration was observed 2, 4, and 8 h after insemination. Sperm penetration was successful in 40%, 60%, and 69% of the oocytes treated for 10 min with heparin. Feminine and masculine pronuclei were clearly identifiable. In these samples, 80% of the sperm was alive and there was approximately 68% progress motility. Live sperm were observed for up to 24 h. Since glycosamineglycan sulfates are normally present in the ooplasm, zona pellucida, follicular and uterine fluids, this might suggest a direct participation of heparin in human sperm capacitation.

Animals↗
PubMed1983

Effect of zinc on decondensation of human spermatozoa nuclei by heparin.

Swelling sperm nuclei were assayed, exposing them to the combine action in increasing amounts of seminal plasma 0.1-1.0 ml (124 +/- 21 micrograms of Zn++/ml). An inhibition of almost 30% in the swollen spermatozoa nuclei was observed with 0.1 ml of seminal plasma (12 micrograms of Zn++/ml) reaching to 71% with 74-124 micrograms of Zn++/ml. Inactivated seminal plasma (boiling) induced the same percentage of inhibition (73%) than normal seminal plasma. Dialyzed seminal plasma (31 micrograms of Zn++/ml) produced an inhibition of 88% of swollen spermatozoa nuclei, the same percentage produced with 30-35 micrograms of zinc ions (ZnCl2). Previous release of sperm zinc by preincubation with EDTA 6 mM changed the decondensation kinetics, making sperm nuclei more susceptible to the action of the glycosaminoglycan. No effect was observed in the presence of calcium ions. Therefore, zinc, among its several physiological roles, may act as a nuclear chromatin stabilizer.

Cell Nucleus↗
PubMed1983

Heparin-induced nuclei decondensation of mammalian epididymal spermatozoa.

Decondensation of mammalian epididymal spermatozoa nuclei has been induced by exposure of intact spermatozoa to heparin, including those species in which ejaculated sperm were not susceptible to this treatment. This process occurred in the absence of any disulfide bond cleaving reactant. Swelling of caput epididymal spermatozoa nuclei commenced about 30 min after the addition of heparin, reaching 88% in rat, 33% in rabbit, 26% in pig, and 62% in bull of swelled nuclei after 6 hr of incubation at 37 degrees C with 5000 USP of heparin per ml. Corpus epididymal spermatozoa nuclei of rat and rabbit underwent decondensation at 50 degrees C reaching 24% and 22% of swelled nuclei, respectively, after 6 hr of incubation. The nuclei of the sperm cells of pig and bull from this epididymal region remained highly condensed as well as the nuclei of the cauda epididymal spermatozoa of all the species assayed. Electron microscope observations of the caput epididymal spermatozoa nuclei treated with heparin revealed that the chromatin is organized into nuclear bodies joined by a network of cross-linked and branched chromatin fibers in the species studied.

Animals↗
PubMed1983

Oxygen consumption of elderly persons with bilateral below knee amputations: ambulation vs wheelchair propulsion.

Elderly bilateral below knee (BK) amputees were tested for oxygen consumption (VO2), heart rate (HR) and velocity (V) during ambulation on a 40m walkway and a stationary wheelchair ergometer. Values obtained from amputees were compared to values obtained from a control population of the same age group. On test day 1 bilateral amputees and normal subjects ambulated at their natural pace on a walkway for approximately 5 minutes. On test day 2 each subject propelled a stationary wheelchair ergometer at their natural rate for the same distance that they ambulated. Measurements of VO2 (ml/m/kg), HR (beats/min), and V (m/min) were obtained during both sessions. Results show that the bilateral BK group required significantly more VO2 (ml/m/kg) (123%), had higher HR (26%), and slower V (36%) than the normal group during ambulation. The energy cost in terms of ml/min/kg during ambulation was similar, suggesting that the amputees ambulated at the same power cost as normals but at lower velocities. During wheelchair propulsion the BK group and normal group showed no significant difference in the 2 criteria. Results suggest that wheelchair propulsion is a more energy efficient mode of mobility for elderly bilateral BK amputees than ambulation. Energy cost and heart rate determinations may be valuable in choosing the course of mobility training and recommended activity levels. Cosmetic, psychosocial, and other clinical factors must be considered in prescribing rehabilitation.

Aged↗
PubMed1982

Decondensation of human sperm nuclei by glycosamineglycan-sulfate from sea urchin egg.

Decondensation of human and sea urchin spermatozoan nuclei has been induced by exposure of intact spermatozoa to glycosamineglycan-sulfate (GAGs) extracted from eggs of the sea urchin. Toxopneustes roseus. Swelling of human spermatozoan nuclei commenced about 60 min after the addition of GAGs and, depending on the extract concentration, the proportion of swollen nuclei reach 90% after 6 h of incubation when 20 mg of GAGs per ml was used. Swelling of sea urchin spermatozoan nuclei could be induced also with GAGs and/or with heparin. Swelling commenced about 10 min after the addition of GAGs/heparin reaching 90-92% after 60 min of incubation with 5 mg GAGs/500 USP heparin per ml. Preincubation of spermatozoa with 10 mg/ml of trypsin soybean inhibitor did not interfere with the swelling action of the GAGs.

Animals↗
PubMed1982

Heparin binding sites in the human spermatozoa membrane.

The existence in the human spermatozoa membrane of receptorlike functional group for heparin was studied. Incubation of whole spermatozoa with tritiated heparin induced the specific binding of 745 +/- 112 pmol of heparin per 5 x 10(7) sperm cells with an intrinsic association constant KD = 3.6 x 10(-6) M. The specificity of binding was shown by the lack of competence in the binding process of some other glycosaminoglycans used at concentrations 20 x higher than heparin. However, dextran sulfate was a very efficient competitive agent. Autoradiography experiments showed that labeling was almost completely restricted to sperm cells in the process of nuclear decondensation. This technique showed the presence of a high amount of radioactive heparin in the isolated sperm membranes even after several washings. Heparin may participate both in the final part of the capacitation process (acrosome reaction) and in the decondensation of sperm nuclei.

Binding Sites↗
PubMed1981

Exchange of lipids between spermatozoa and seminal plasma in normal and pathological human semen.

Normal and pathological semen were studied with regard to cholesterol and phospholipid content of sperm cells and seminal plasma. Spermatozoa from pathologic semen have similar concentrations of phospholipid-phosphorous and significantly higher cholesterol concentration than spermatozoa from normal semen. However, only oligoasthenospermic spermatozoa showed a significantly higher cholesterol/phospholipid ratio. Azoospermic seminal plasma showed the lowest values of both cholesterol and phospholipids, but the ratio of cholesterol to phospholipids was equal to that in normal spermatozoa. No significant difference was found in the cholesterol concentration of seminal plasma from oligoasthenospermic, asthenospermic, and normospermic subjects and only asthenospermic plasma showed a significantly lower concentration of this compound. Cholesterol and phospholipid exchange between sperm cells and seminal plasma was shown by the striking correlation between the lipid composition of seminal plasma with that of sperm cells.

Cholesterol↗
PubMed1980

Species specific decondensation of human spermatozoa nuclei by heparin.

Decondensation of human spermatozoa nuclei has been induced by exposure of intact spermatozoa to heparin, while the spermatozoa of rabbit, ram, and bull remained highly condensed under similar experimental conditions. This process occurred in the complete absence of any disulfide bond cleaving reactant. Swelling of human spermatozoa nuclei commenced about 30 min after the addition of heparin and depended on heparin concentration reaching 83% of swelled nuclei after 6 hr. of incubation with 5000 USP of heparin per ml. Addition of 10 mg/ml of trypsin soybean inhibitor did not interfere with the swelling action of heparin. Electron microscope observations of human spermatozoa nuclei treated with heparin revealed that the chromatin is organized into "hublike" nuclear bodies joined by a network of cross-linked and branched chromatin fibers ranging in thickness from 25 to 1.5 nm.

Animals↗
PubMed1980

Changes in free aminoacid contents of erithrocytes and leukocytes during pregnancy.

Erythrocyte participation in the transfer and exchange of amino acids with tissues has been recently demonstrated. In this study, we show changes in erythrocytes, leukocytes and plasma free amino acid content, from peripheral blood in a group of 10 women after 25 weeks of gestation. Also tryptophan determinations in plasma and erythrocytes were made by fluorometric methods. During pregnancy, eleven of the 21 plasma amino acids studied are significantly different and the essential/nonessential ratio is not modified, although the total content diminished significantly. Conversely, in erythrocytes and leukocytes results indicate increase a in 2 and 3 fold respectively, in contents of aminoacid during gestation. The essential/nonessential ratio increases in the erythrocyte; In the essentials amino acids threonine, isoleucine and histidine show a greater increase. In leukocytes, the essential/nonessential ratio decreases during gestation due to a great increase of nonessentials, nevertheless, threonine, valine, methionine and leucine also show values significantly higher values during pregnancy. When amino acid content is calculated by mg of protein we see a certain increase in plasma, not significant, during pregnancy; in leukocytes, this increase corresponds almost to 90 per-cent with respect to the control group.

Adult↗