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Biomedical subjects

N M Delgado

Publications and source records attributed to N M Delgado.

At least 37 records · Page 2Linked to original sources
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↗
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↗
PubMed1978

Metabolic changes induced in human spermatozoa by subagglutinating concentrations of specific antibodies.

The effects on sperm metabolism of subagglutinating concentrations of infertile female sera, containing antisperm antibody, were studied. Sera were selected by their differential agglutinating or immobilizing properties and by high titers of activity. Only the immobilizing antibodies were able to decrease sperm viability. Basal and succinate depending oxygen uptake, thus as progressive motility was decreased by sera producing mixed agglutination and more drastically by that producing immobilization independent of the presence of complement. The sera with head-to-head agglutination properties induced an increase in the above mentioned physiologic parameters. Tip of tail-to-tip of tail agglutinating sera having no effect on oxygen uptake were able to induce a significant increase in progressive motility. Conversion of 14C-Glucose to 14CO2 was decreased by sera that induced tip of tail-to-tip of tail agglutination and complement-independent immobilization. The sera which induced head-to=head agglutination and immobilization on the presence of complement, were without effect. None of the tested sera showed any acitivity over the conversion of 14C-Glucose to 14C-Lactate.

Antibodies↗
PubMed1977

Cyclic changes in salivary activity of N-acetyl-beta-d-glucosaminidase; a possible efficient indicator for predicting ovulation and pregnancy.

Salivary activity of N-acetyl-beta-D-glucosaminidase showed a characteristic pattern of changes during the normal menstrual cycle with a distinct peak on Day 13, 14, or 15 before the next menstruation. This peak of enzyme activity occurred withing one day of the nadir of basal body temperature and was absent in women with spontaneous or iatrogenic anovulatory cycles. These results are stongly suggestive that the salivary determination of this activity may be convenient indicatior for determining the day of ovulation.

Body Temperature↗
PubMed1977

Osmolality and conductance of normal and abnormal human seminal plasma.

The possible correlation between two important general properties of seminal plasma, osmolality and conductance, and the presence of some pathological conditions of human semen, asthenospermia and oligoasthenospermia, have been studied. Osmolality was measured under carefully controlled conditions by the freezing point depression method and conductance with a Wheatstone bridge. In addition, volume, by an isotopic dilution method, and pH were also determined. Osmolality of normal human seminal plasma (366 +/- 16 mOsm/Kg) was found to be higher than the osmolality of human blood serum. Abnormal seminal plasma showed a still higher value (428 +/- 38 and 457 +/- 49 mOsm/Kg respectively for astheno- and oligoasthenospermic subjects). Incubation of normal seminal plasma for 24 hours at room temperature produced a significant increase in osmolality (from 366 +/- 16 to 430 +/- 31 mOsm/Kg) while pathological seminal plasma failed to show any modification. Osmolality and conductance values were found to be correlated with semen ejaculated volume in normal subjects. No difference in mean conductance value was found between normal and asthenospermic individuals (10.4 +/- 1.2 against 9.9 +/- 1.0 mhos X 10(-3) respectively). Oligoasthenospermics showed, on the contrary, a significantly higher conductance (12.4 +/- 1.6 mhos X 10(-3)).

Adult↗
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↗
PubMedDate not supplied

Nucleons II: cryopreservation and metabolic activity.

The establishment of intracytoplasmatic sperm injection (ICSI) as a routine procedure in assisted fertilization has been used in the treatment of male infertility. The major technical problem that has arisen with the use of immotile sperm for ICSI has been differentiating between live and dead cells. Nucleons from human, pig, hamster, mouse, rat, and bull have been able to induce their chromatin decondensation by the action of heparin/GSH. Cryopreservation is deleterious to sperm function, killing more than 50% of the spermatozoa during the process. Nucleon cryostorage was performed at 5 and -5 degrees C and analyzed for total area (mu2), perimeter (mu), width (mu), and length (mu), using Metamorph Imaging System software. On the other hand, fluorescein diacetate (FDA) is hydrolyzed by intracellular estereases to produce fluorescein, which exhibits green fluorescence when excited by blue light. This fact is a striking result since the presence of this metabolic activity opens the possibility to select the nucleons for ICSI. In the present study, the authors decided to search for a suitable metabolic test, which might reflect the metabolism and viability of these chromatin structures. This is a simple cryostorage technique that after months of cryopreservation, allow the use of nucleons for ICSI with suitable fertilization and pregnancies rates.

Animals↗