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L Huacuja

Publications and source records attributed to L Huacuja.

At least 19 recordsLinked to original sources
PubMed1992

Capacitation and acrosome reaction of human spermatozoa. An assisted reproduction approach.

In this paper we briefly review the recent advances in the understanding of human sperm capacitation, fundamentally focused to give help to the practitioners involved in assisted reproduction. Sperm capacitation has been the subject of study for many years in several animal species, but during the past ten years the advances in assisted reproduction procedures have made important contributions in the progress of this topic in relation to human spermatozoa. In this manuscript we analyze the metabolic, membranal and physiological changes observed in these cells during in vitro capacitation and their relationships with the female genital tract secretions, as well as with the homologous oocytes.

Acrosome↗
PubMed1990

Differences in lipoprotein composition between heads and tails of human sperm: an infrared spectroscopy study.

Human spermatozoa and their fractions (heads and tails) have been studied by infrared spectroscopy. Protein conformation in isolated human spermatozoa heads, although predominantly of the alpha helix or random coil type, has a significant proportion of antiparallel B structure. Spectra of isolated spermatozoa tails show that proteins exist in this fraction preponderantly in pleated-sheet conformation (parallel and antiparallel). The quantity and type of lipids seem to be drastically different between heads and tails of spermatozoa. Head lipids are scarce and difficult to extract, and they are apparently tightly bound to proteins, highly unsaturated, and rich in free hydroxyl and carboxyl groups. Tail lipids are more abundant and more easily extractable. Head phospholipids are probably phosphatidylcholine, cephalins, and inositols, and tail phospholipids are preponderantly plasmalogen-type lecithins and sphingomyelins. The presence of specific infrared bands points to the existence in tails of important amounts of sulfur compounds, probably sulfolipids or sulfoglycolipids.

Humans↗
PubMed1990

Glycosaminoglycan-sulfate as plasma membrane component of pig spermatozoa.

The effect of specific glycosaminoglycan-hydrolyzing enzymes on the ruthenium red staining of pig spermatozoa was studied. Washed spermatozoa were incubated at 35 degrees C in buffer or with neuraminidase 0.5 units/ml, heparinase 0.2 mg/ml, or chondroitinase ABC 2.0 units/ml. After incubation sperm cells were washed, stained with ruthenium red and studied under the electron microscope. Anionic sites in the surface of untreated spermatozoa follow regularly the plasma membrane, but present are numerous processes constituting what has been defined as the glycocalyx. Neuraminidase did not affect the distribution of ruthenium red on the surface of the spermatozoa, but eliminated almost completely the processes of the glycocalyx. Heparinase caused loss of the ruthenium red-stained sites on the membrane surface of pig spermatozoa with less influence on the dense processes of the glycocalyx. A similar loss of ruthenium red-stained sites was observed with nitrous acid treatment. A striking effect of treatment with chondroitinase ABC was the production of a typical acrosome reaction.

Animals↗
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↗
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↗
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

Male pronuclei formation release of phosphorylation of histone H-3 during decondensation of human sperm nuclei activated in vitro by heparin.

The release and phosphorylation/dephosphorylation mechanisms of human spermatozoa histone during nuclei in vitro decondensation by heparin was studied. Washed sperm cells were incubated in the presence of 32P and in the absence or presence of heparin. The results showed an increase in the incorporation of 32P of 20 times greater in the presence of heparin than in the absence of heparin (the control sample). In some cases the incorporation of 32P into histones was confirmed by its isolation. To validate these results a phosphorylation kinetic of isolated sperm histone, used as a substrate, was performed. The amount of 32P was not a linear function of time, and maximal phosphorylation was reached in 60 min. A measurement of 32P incorporated as a function of the amount of histone, shows a linear relationship of up to 50 micrograms of protein, with a rapid saturation thereafter with the incorporation of 220 nm and with a KD = 442 x 10(-6) mol/L. 32P incorporation, independent of exogenous cAMP, was related to alkaline pH but was totally dependent on temperature--with a maximum of 37 degrees C. The only histone released was histone H-3. Phosphorylation/dephosphorylation is involved during male pronuclei formation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

Human urinary glycosaminoglycans as accurate method for ovulation detection.

Urinary glycosaminoglycans (GAGs) content showed a characteristic pattern of fluctuation during normal and hormonally induced cycles with a distinct peak at ovulation. This peak of maximal GAGs concentration (106.7 +/- 46.2 micrograms/mL in urine) was centered according to the day of the midcycle LH surge, which serves as the reference point, designated day 0. All cycles are presumed to be ovulatory on the basis of biphasic BBT nadir, ultrasonographic studies, and progesterone assays (greater than 5 ng/mL of serum) during the secretory phase. In hormonally induced menstrual cycles, a noticeable increase in GAGs concentration (70%) was observed. This indirect evidence suggests a possible correlation between GAGs content and hormonal effect. All types of GAGs, with the exception of heparin, have been found in urine, chondroitin sulfate C being the major component at time of ovulation. These results strongly suggest that urinary GAGs determination is a precise method for ovulation detection.

Adult↗
PubMedDate not supplied

A rapid method for ovulation detection.

Uronic acid (UA) content in whole urine showed a characteristic pattern of fluctuations during menstrual cycle (24 cycles) with a distinct peak on the day of ovulation (midcycle peak 1043 + 68 micrograms/ml urine. This peak of maximal UA concentration was validated by ultrasonography (abdominal and/or vaginal scanner and basal body temperature. In hormonal induced menstrual cycle (5 cycles) a significant decrease in Ua concentrations were observed during the follicular phase (20%) and in the midcycle peak (11%) when they were compared with the same values in the normal cycle. Nevertheless, two days after the ovulation peak occurs a second peak can be observed (1344 + 799 micrograms UA/ml urine). On the other hand in the anovulatory cycles (5 cycles) the same diminishing behavior in the UA concentrations were observed in both phases of the cycle (50-60%) with the expected lack of the midcycle peak. Results that clearly show that UA excretion in urine reflect a excellent correlation with the menstrual cycle allowing us to propose this technique as an accurate and reliable method to detect ovulation.

Adult↗
PubMedDate not supplied

[Follicular maturation in the swine. Changes in the protein secretion pattern during follicular growth].

The formation of fluid, maturation and follicular differentiation are physiological processes unknown to this date. Therefore, changes in the electrophoretic pattern of proteins and glycoproteins in different states of maturation were studied, as well as the volume and protein concentration. Follicular fluid was collected from 43 follicles with a diameter of 2 mm., 45 follicles with a diameter of 5 mm. and 49 of 9 mm. The average of the concentration of protein for the 2 mm. follicles was 106 +/- 56.3 mg/ml of follicular fluid, for the 5 mm. ones 68.3 +/- 37.1 mg/ml and the 9 mm. ones had 52.9 +/- 21.3 mg/ml. In the protein and glycoproteins characterized by electrophoresis, a consistent pattern of 3 bands was found, and none were PAS positive in the 2 mm. follicles. In the 5 mm. follicles a 10 band pattern was found, of which 1 was PAS positive. In the last plane, the 9 mm. pattern was 12 and 2 respectively. The average value of follicular fluid was 5.3 +/- 1.8 microliters, for the 5 and 9 mm. it was 57 mu 25 microliters and 190 +/- 77 microliters respectively. Statistical analysis between volume and size show a highly significant correlation, thus suggesting the use of one of them to extrapolate the other.

Animals↗