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Biomedical subjects

A Rosado

Publications and source records attributed to A Rosado.

At least 73 records · Page 4Linked to original sources
PubMed1986

Treatment of glaucoma with high-intensity focused ultrasound.

This report is a summary of results for 170 eyes of patients with refractory glaucoma treated with high-intensity focused ultrasound. The results are analyzed in terms of the effectiveness of various treatment regimens, complications, and classifications of the patient population according to such factors as age and etiology. The mean pretreatment intraocular pressure (IOP) for the ensemble of patients treated with optimal intensity levels was 38.6 mmHg. Whereas only 10% of these patients had an IOP of 25 mmHg or less prior to treatment, 90% had an IOP of 25 mmHg or less within 3 months of treatment. At 1 year after a single treatment, 65% of patients still maintained intraocular pressures of 25 mmHg or less, and 56% had pressures of 22 mmHg or less. The effectiveness of retreatment of failed or unresponsive cases was also investigated and found to have a degree of success comparable to that of initial treatments.

Choroid↗
PubMed1985

Treatment of experimental lens capsular tears with intense focused ultrasound.

High-intensity focused ultrasound was employed to seal lens capsular tears in a rabbit model. Ultrasound therapy was applied either contiguously, thereby completely covering the tear, or in a discrete exposure pattern around the tear. Both methods prevented the formation of a generalised cataract. This was in contrast to results observed in a group of control (untreated) animals which all developed generalised lens opacities. Each control animal also developed a local lens opacity at the site of the capsular tear, as did half the animals treated with the discrete pattern. No animal treated with contiguous exposures developed any local or generalised traumatic-type cataract other than the small lens opacity immediately produced by the treatment. These treatment cataracts would not constitute a significant impediment to vision so long as they did not fall on the visual axis.

Animals↗
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↗
PubMed1983

Effect of steroid hormones on membrane sugar transport in human spermatozoa.

Using the model of exchange transport, we found that glucose transport through the human spermatozoa membrane (447 +/- 54 pmoles/min/10(8) cells) is probably the rate-limiting step in sugar utilization. Sugar transport was more efficient for glucose than for fructose (182 +/- 32 pmoles/min/10(8) cells) and depends on a highly asymmetric carrier with at least two transporting sites. Transport was drastically dependent on pH with an optimal pH of 7.4, showing a decrease of more than 60% with a change of 1 pH unit. Testosterone and 17-B estradiol increased the amount of transported sugar (619 +/- 73 and 922 +/- 110 pmoles/min/10(8) cells, respectively), while progesterone has no effect.

Biological Transport, Active↗
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↗
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↗
PubMed1981

Differential distribution of cyclic-AMP receptors in human spermatozoa.

The binding properties of cyclic-AMP to intact and fractionated in heads and tails human spermatozoa have been studied. Whole spermatozoa bound 6.8 +/- 0.8 pmol of cyclic-AMP per 10(7) cells. Binding of cyclic-AMP was selectively located in the midpiece-tail region of the spermatozoa. Thus only 18% of the binding in the whole sperm could be accounted for by the binding on the sperm heads. This distribution is similar to that previously described for the protein kinase of bovine sperm. Blocking membrane sulfhydryl groups with pCMBS induced a drastic inhibition (65%) of the cyclic-AMP binding to the sperm heads, while only moderately reducing (30%) the binding in the sperm tails

4-Chloromercuribenzenesulfonate↗
PubMed1981

Intrauterine release of progesterone: changes in RNA patterns of endometrium.

The changes induced in the relative concentrations of the different species of RNA (messenger, ribosomal, transfer and heterogenous) which regulate the metabolic behavior of tissues were studied in the endometrium of normal women and in women wearing a progesterone T IUD for 6-12 months. It was observed that the intrauterine release of progesterone is accompanied by a significant decrease in the content of total RNA (from 78 +or- 8.4 to 64 +or- 6.7 mcg/mg of protein) and in the RNA/DNA ratio (from 0.85 +or- 0.10 to 0.73 +or- 0.08). Although the protein decreased significantly (from 102 +or- 11 to 82 +or- 14 mg/g wet wt.), the DNA content and the Prot/DNA ratio were not altered. Using the affinity chromatography technique in poly(u)Sepharose it was found that the relative concentrations of RNA types were in general drastically modified: mRNA and rRNA decreased (from 2.6 +or- 0.31 to 1.28 +or- 0.15 and from 65.5 +or- 8.0 to 54.8 +or- 6.7 mcg/mg of protein respectively). tRNA content was increased (from 6.2 +or- 0.9 to 11.0 +or- 1.3) while hRNA was unchanged. The probable inhibitory effects of these changes in relation to the normal hormonal stimulation of the human endometrium, as a possible explanation of the mechanism of action of this device, are discussed.

Biology↗
PubMed1981

A rapid colorimetric assay for dry weight.

A rapid, precise colorimetric method for the determination of dry weight in the range 100 1,000 micro grams is reported. The method involves reacting biological materials with an acid solution of dichromate for 20 min at 92 degrees C followed by determination of the optical density at 630 nm of the product formed. The principal advantage of the dichromate method over the standard weight method are: 1) The shorter time required for determination, 2) its greater sensitivity, exactitude and precision using standard laboratory equipment, 3) the method is insensitive to inorganic compounds and therefore can be applied to tissue homogenates prepared in inorganic solutions. The only disadvantage of the method seems to be that dichromate will react specifically with carbon containing groups and therefore the participation of nitrogen, or other elements, in the composition of the biological material, will give proportionately lower absorbances.

Animals↗
PubMed1981

History of cancer investigation.

A revision was made of the most important biological hypothesis that try to explain the carcinogenesis mechanism. Most of them postulate that malignization is the result of cell genetic material alterations. On the other hand information obtained from cell exposure to chemical, physical and viral carcinogens was analyzed. Resulting data support the idea that carcinogenesis is carried out by means of somatic mutations. We conclude that internal and external factors are involved in the malignization process and that the approach to the cancer problem might depend upon future advances in molecular genetics and biology.

Animals↗