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Biomedical subjects

E Bustos-Obregón

Publications and source records attributed to E Bustos-Obregón.

At least 19 recordsLinked to original sources
PubMed2005

Effects of chronic hypobaric hypoxia on testis histology and round spermatid oxidative metabolism.

In order to evaluate the effects of the exposition to continuous chronic hypobaric hypoxia (CCHH) and intermittent chronic hypobaric hypoxia (ICHH) on testis histology and on oxidative metabolism of spermatogenic cells (SC), male rats were exposed to a 4600-m simulated altitude (PO2: 89.6 mmHg). After 60 days, ICHH and CCHH groups presented a significant decrease in testicular mass, an increase in interstitial space, a decrease in height of the seminiferous epithelium, depletion of cellular elements, vacuolization in epithelial cells and folding of the basal membrane. Round spermatids from animals exposed to CCHH presented a significant decrease in energy-dependent cell shape changes. Round spermatid mitochondria of CCHH rats seem to be limited in their ability to handle reducing equivalents. These mitochondria also appear to be uncoupled under basal conditions. Round spermatids from CCHH rats evidence large oxygen consumption (QO2) insensitive to inhibition by cyanide, a process that could be partly related to lipoperoxidation. Thus, exposure of male rats to CCHH and ICHH induced evident changes in testicular morphology and loss of spermatogenic cells, in all stages of the spermatogenic cycle. This post-meiotic spermatogenic cell loss in the testis correlated well with metabolic changes in round spermatids that evidenced a strong metabolic stress in these cells.

Animals↗
PubMed2005

Melatonin as protective agent for the cytotoxic effects of diazinon in the spermatogenesis in the earthworm Eisenia foetida.

Diazinon (D) is an organophosphorate synthetic insecticide widely used in the world. It inhibits acetylcholinesterase activity and damages reproduction as well as other organic functions mostly by increasing lipid peroxidation. Melatonin (M) is an indolamine secreted by the pineal gland. It performs numerous functions but recently it has been proposed as a good scavenger of oxygen radicals. The earthworm E. foetida is reputed as an excellent bioindicator of environmental chemical pollution. The testicular toxic effect of D and the protective role of M was analyzed in adult E. foetida, at 1, 7, 10, 15 and 30 days after exposure to 1/4, 1/2 and 3/4 of LD50. Sperm counts and the diameter of the seminal receptacles and of their lumina were altered in D exposed worms, which in addition have a lower percentage of survival, decreased weight and show cholinergic effect (coiling of the tail). All these changes were prevented fully or in part by simultaneous exposure to M. The observations confirm that D is a general and testicular toxicant for E. foetida, a good sentinel indicator and stresses the role of M as a protective agent.

Animals↗
PubMed2004

Update on the impact of Chlamydia trachomatis infection on male fertility.

With approximately 90 million cases annually, infection with Chlamydia trachomatis is the most prevalent sexually transmitted bacterial disease in the world. Considering that these infections are often asymptomatic and cause major complications like acute pelvic inflammatory disease, ectopic pregnancy, infertility or infant pneumonia, the estimated costs for diagnosis and treatment in the USA amounts to 2.2 million US dollars for each 500 cases. Therefore, there is a high need for correct, quick and cost-effective diagnosis and treatment of this urogenital tract infection. New innovative therapies provide good results with regard to efficacy and patients' compliance. The success rates of treatments are at least 95%. However, the occurrence of antibiotic resistance should not be ignored and new treatment schemes must be developed. The state-of-the-art of diagnosis and treatment of chlamydial infections as well as the pathophysiology is discussed in this review. In conclusion, infections with C. trachomatis is an important public health problem, especially in third world and developing countries, and more socio-economic studies linking secondary prevention of chlamydial infections, infertility and adverse pregnancy outcome are needed to understand more of its aetiology. In addition, diagnosis and treatment should be improved. Data in men revealed that past infections but not present infections are more related to male infertility. There is still controversial results. In future studies, function of the seminal vesicles and evaluation of the antioxidant capacity should be taken into account when role of C. trachomatis infection on male fertility is assessed.

Chlamydia Infections↗
PubMed2003

Serum reproductive hormone levels and sperm production in male adult rats after treatment with arresting, a fraction obtained from seminiferous tubules conditioned medium.

This study used seminiferous tubule (ST) segments from adult rats to condition culture medium that had been concentrated, size fractioned and administered 10-84 days to adult rats by subcutaneous or intratesticular injection and the effects on testes weight, testosterone, luteinizing hormone (LH) and FSH levels and (homogenization-resistant) epididymal sperm count were determined. The conditioned medium obtained 2 days after culture of ST was fractionated in a 30-100 kDa component. The fraction was injected subcutaneously or intratesticularly. This factor(s), named arresting, decreases sperm count in the epididymis from 13 days to 84 days of treatment without changes in serum LH or testosterone levels. The results of the present study suggest that arresting acts on spermiogenesis/spermiation and/or the entry of sperm into the epididymis from the efferent ductules.

Animals↗
PubMed2002

Alpaca semen characteristics previous to a mating period.

Increasing the knowledge of the semen characteristics in the alpaca will contribute to understanding one of the many factors that affect the poor fertility rate in this species. Ten adult male alpacas, 2.6-10 years of age, average weight 64.7 +/- 4.7 kg were used. The animals were distributed randomly into two groups of five each and submitted alternatively to two semen collections, using an artificial vagina and sexually receptive females. For the first semen collection the animals had a sexual rest period of about 90 and 45 days before the second. Duration of semen collection, color and volume of ejaculate were recorded, and sperm concentration and morphology (light microscopy) were evaluated. Descriptive statistical analyses were used for each variable, considering all samples obtained (n= 19). An analysis of variance for animal groups and opportunity of collection were used for quantitative variables. Most frequent color was opalescent white (84.2%). There were no statistical differences among male groups or between semen collections. The average values and standard deviations for the quantitative variables were: 12.3 +/- 7.2 min for semen collection time, 1.8 +/- 0.8 ml for ejaculate volume, (17.6 +/- 26.1) x 10(6) sperm/ml for sperm concentration and 34.0 +/- 52.2 x 10(6) for total number of sperm per ejaculate. The percentage of normal spermatozoa was 51.0 +/- 12.4%. From the total abnormalities, that of mid piece segment (14.4%) was the most frequent. These results indicate that male alpaca have poor semen quality, when compared with other domestic species. Nevertheless, for the evaluation of male alpaca as breeders it would be necessary to create a protocol for the selection of them, where phenotypic, behavioral and seminogram aspects are considered. The values reported herein define the characteristics of the alpaca semen that could be considered as the initial base of the seminal analysis to select male alpacas before mating.

Animals↗
PubMed2002

Morphometric characterization and classification of alpaca sperm heads using the sperm-class analyzer computer-assisted system.

Sperm morphology has been identified as one characteristic which can be useful in the prediction of sperm fertility, therefore, we hope that this study aimed at establishing standardized morphological criteria might serve in future studies dealing with the search for sperm parameters which facilitate an estimation of sperm quality. For this purpose, ejaculates from fertile alpacas were used to evaluate sperm head morphometry by means of the Sperm-Class Analyzer (SCA) computer-aided image analysis system. We defined three morphological categories according to sperm head size (normal 50%, small 26%, large 24%) and five categories according to sperm head shape (normal 47%, pyriform 3%, short 20%, round 1%, long 29%). Sperm classification according to shape was performed by first morphometrically characterizing sperm heads clearly falling into each of the shape categories. Thereafter, discriminant analysis was performed on the data from these typical sperm heads and the resulting classification functions were used to categorize 2,200 spermatozoa from 11 alpacas. Classification of sperm heads by this method agreed in 88% of the cases with most of the misclassifications being due to pyriform heads classified as long heads. Morphometric values obtained from samples of 50, 100, 150, 175 and 200 sperm heads were compared. At least 150 sperm heads should be evaluated to overcome sample size influence on sperm measurements. Significant differences in sperm morphometry were found between individuals (CV for morphometric parameters ranging from 1.3 to 13.0) and there were marked differences in the sperm morphological composition of the ejaculates. Within-animal CV ranged from 4.7 to 17.8 thus showing the high degree of sperm polymorphism present in the alpaca ejaculate.

Animals↗
PubMed2001

The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid.

In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50%) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.

Acrosome Reaction↗
PubMed2001

Parathion induces mouse germ cells apoptosis.

Germ cell loss occurs in normal spermatogenesis at defined stages of the seminiferous epithelial cycle. The process has been known for over a century but only recently it was analyzed under the concept of apoptosis. This is a programmed cell death that occurs during development and also in the adult. It is believed to play a key role as quality control in sperm formation, avoiding the passage of genetic defects to future generations. Chemical toxicants may increase apoptosis, disturbing tissue homeostasis. The effect of the agropesticide parathion upon apoptosis in mouse seminiferous tubules was analyzed in young mice (onset of spermatogenesis) and in adult animals (full spermatogenesis). In both young and adult mice, the pesticide increases the rate of apoptosis, which takes place at stages where spermatogonial proliferation occurs, affects spermatocytes at the beginning of the meiotic process and spermatids at the elongating period. Basal apoptotic rates are greater in young mice. In adults, commercial parathion is more toxic than the pure organophosphoric compound. From these observations plus in vitro effects of parathion reported previously, it can be concluded that the pesticide affects DNA (and RNA and protein) synthesis. The effect is reversible with moderate doses of the chemical after acute intoxication.

Aging↗
PubMed2000

Morphology of testis and epididymis in an ethanol-drinking rat strain (UChA and UChB).

The objective of the present study was to analyze the prospective alterations of the testis and epididymis in a defined strain of alcoholic rats in order to contribute to our understanding of the effects of chronic alcoholism on reproduction. The testis and epididymis of the animals were submitted to morphological analysis by macroscopy, light microscopy and electron microscopy and to morphometric analysis. The UCh rats showed atrophy of the epithelium and reduction of testis and epididymis weight, liver hypertrophy and fat infiltration and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the weight and in the epithelium of the testis and epididymis and in the hypothalamus-pituitary axis of the UCh rats.

Alcoholism↗
PubMed2000

Sperm quality in mice acutely treated with parathion.

AIM: To investigate the toxic effect of a single injection of the organophosphorous agropesticide, parathion, on spermatogenesis in immature male mice. METHODS: Seven-day old mice received a single injection of parathion intraperitoneally at a dose of 1/3 LD50. The epididymal sperm count, sperm morphology and chromatin thermal stability were analyzed 28 and 50 days after injection. RESULTS: Sperm counts were decreased and teratozoospermia and thermal denaturation of DNA increased after parathion injection. Sperm parameters were changed to a greater extent in younger animals, denoting a higher lability of spermatogenic process at its beginning. The damages could recover a long time after parathion administration. CONCLUSION: Organophosphorous agropesticides are testicular toxicants, eliciting reversible cytotoxic and cytogenetic alterations in germ cells.

Animals↗
PubMed1999

Morphological alterations in mouse testis by a single dose of malathion.

Malathion((R)) is a widely used organophosphorate agropesticide. In spite of its low toxicity for mammalian cells, it provokes cytogenetic and genotoxic damage both in vivo and in vitro. The effect of Malathion was analyzed in CF-1 young adult male mice. Commercial Malathion (96.6% purity) was injected intraperitoneally in a single dose (250 mg/kg body weight corresponding to 1/12 LD50). Four, 14, 18, and 26 days after injection animals were sacrificed to study epididymal sperm (count and morphology), testicular histology (percentage of depleted seminiferous tubules), and ultrastructural alterations in the germinal epithelium. The effect of Malathion on different germinal cell populations was studied. Teratozoospermia was induced by Malathion at all times studied. Spermatozoa midpiece and flagella were the most affected and at day 18 we observed less alterations of the head. The sperm count at different time intervals was significatively increased compared to controls and there was a parallel increase in depletion of the seminiferous tubules. In conclusion, all germinal cell populations studied were affected by Malathion. Malathion has a teratogenic effect on mice spermatid differentiation, which compromises mostly the flagella, perhaps due to an alkylating effect that disturbs the normal assembling of tail structural protein components. Apparently, the pachytene spermatocyte stage may be relatively more resistant to the pesticide. The Sertoli cells were affected by the insecticide and their damage at an ultrastructural level is highly significant. Cytoplasmatic vacuolization probably revealed metabolic alteration of these cells.

Animals↗
PubMed1999

Biological activity of the seminal plasma of alpacas: stimulus for the production of LH by pituitary cells.

South American camelids are induced ovulators and require a stimulus to trigger the LH surge responsible for the ovulation. Seminal plasma (SP) of fertile alpacas (Lama pacos) was tested using a bioassay of pituitary cells to study the effect of seminal plasma on LH release. Plates containing rat pituitary cells (2 x 10(5) cells/90-95% viability) were cultured adding: (A) whole SP (WSP) treated with charcoal-dextran, or 1:2 or 1:4 proportions diluted in culture medium (DMEM/HEPES + antibiotics), or (B) 1:2 SP + anti-GnRH rabbit serum (inhibitory potency 10(-5) M), or (C) 1:2 SP + anti-GnRH + 100 nM synthetic GnRH (buserelin acetate) or (D) 100 nM, 50 nM, 10 nM, and 1 nM synthetic GnRH. Concentration (ng/ml) of LH secreted (Sec) and contained (Con) was analyzed using RIA 125I and the percentage of Sec and Con in each experiment was determined. The results of LH Sec for the cells treated with 50, 10, and 1 nM GnRH were 39, 13, and 1.5%, respectively (r2 = 98.41%, r = 0.9920) but cells treated with 100 nM GnRH secreted 10% of LH. With WSP, 1:2, or 1:4 SP the LH Sec was of 44.5% (3.25 ng/ml), 27% (1.9 ng/ml), and 18% (1.2 ng/ml), respectively. The exposure of cells to 1:2 SP + anti-GnRH, or to 1:2 SP + anti-GnRH/100 nM GnRH produced 31% (2.20 ng/ml) and 30% (1.8 ng/ml) of LH Sec, respectively. These results suggest that the SP of alpacas could have some factor(s) different from GnRH that would contribute to the mechanisms of LH secretion and to the induced ovulation in the female alpaca.

Animals↗
PubMed1999

Distribution of keratins, vimentin, and actin in the testis of two South American camelids: vicuna (Vicugna vicugna) and llama (Lama glama). An immunohistochemical study.

The purpose of the present study was to investigate the pattern of distribution of cytokeratins, vimentin and muscular actin in the testis of vicuna (Vicugna vicugna) and llama (Lama glama) two species of camelids native of the Andean high plateau of South America. Testicular biopsies of four vicunas and five llamas were used. Animals were healthy breeders. The tissues were processed by standard immunohistochemistry with antipancytokeratinAE1/AE3, antikeratin 18 (K 18), CAM 5.2 (antikeratin 5, 18, and 19), antivimentin, and smooth-muscle-specific antiactin antibodies to track the cytoskeletal pattern of testicular cells. Using AE1/AE3 antibody the immunostaining was found in the epithelial lining of tubuli recti and rete testis. The reaction was relatively stronger in the apical cytoplasm of epithelial cells. The testicular cells of the two species showed no reaction to K 18 and CAM 5.2 antibodies. Antivimentin antibody stained the basal cytoplasm of the Sertoli cells, the Leydig cells, and the epithelial lining of tubuli recti and rete testis. In the last two structures the immunostain was relatively more intense in the basal cytoplasm of epithelial cells. Antiactin antibody stained the peritubular cells and the muscle cells of the lamina propria oftubuli recti and rete testis. The presence in these species of only some keratins found in man, its coexpression with vimentin in epithelial lining of tubuli recti and rete testis and the peritubule organization, so different from other ungulates may reflect a differential adaptation of the cytoskeleton to particular reproductive strategies.

Actins↗
PubMed1999

Morphofunctional disturbances of human sperm after incubation with organophosphorate pesticides.

The organophosphorate pesticides are highly toxic for insects and mammals, but their effects in the male reproductive tract are scarcely known. Many alterations induced by organophosphorate pesticides have been described, such as: cytogenetic alterations in germinal cells, oligozoospermia and teratozoospermia in the mouse. Parathion, the pesticide mostly utilized in Chilean agriculture, is rapidly metabolized to paraoxon, the active metabolite, in mammalian organisms. The purpose of this study is to evaluate the effect of Parathion and paraoxon on different morphological and functional parameters of the sperm. Human spermatozoa were incubated with Parathion and paraoxon at different concentrations (0.05, 0.1, 0.2, 0.4 and 0.8 mM). Vitality (tripan blue and eosin tests), acrosome reaction (triple stain test), plasma membrane integrity (HOS-test), and chromatin stability (sodium thioglycolate test) were determined. The observations were done by optical microscopy at 1000x of magnification and three hundred sperms were evaluated for each treatment. The results indicated that Parathion and paraoxon increase the percent of sperm with acrosome reaction and also increase the percentage of sperm with chromatin decondensation in a dose-dependent manner. The vitality and plasma membrane integrity decrease significantly in a dose-dependent manner. The results suggest a direct action of Parathion and paraoxon on the different parameters studied. The morphofunctionality of sperm is altered significatively, suggesting that Parathion and paraoxon, thanks to their alkylating and electrophylic properties, could act on DNA and proteins respectively, to elicit these changes.

Humans↗
PubMed1998

The effect of parathion on mouse testicular and epididymal development cultured in chicken allantochorion.

Parathion is a widely used organophosphoric pesticide which has also been reported to interfere with mouse spermatogenesis. Moreover it has been related to prenatal toxicity in mammals. Sixteen A/ Snell mice were sacrificed at day 17 of pregnancy. Testes and epididymides of the male fetuses were implanted in the allantochorion of chicken eggs. Three experimental conditions of the egg injections were considered: Group I: 1 ml of parathion (0.5 mg/ml), Group II: 1 ml of parathion (1 mg/ml), and Group III: 1 ml distilled water (control group). The implanted subjects continued their development for 4 days (i.e. to complete the gestational period for mice). The cell proliferation and differentiation of the epithelial cells of the epididymis were evaluated with the use of the monoclonal antiproliferating cell nuclear antigen (PCNA-cyclin) antibody, and the AE1 keratin complex antibody. Parathion altered the allantochorion, as 15% of the chicken embryos died in Group I and 40% in Group II, vs. only 8% in controls (Group III). However, no malformations were seen in the surviving embryos. In the testicular implants, the seminiferous cords of Group I had the same cytological characteristics of germ and pre-Sertoli cells as the control, except for involuting Leydig cells. Contrarily, in the cases with higher doses of parathion (Group II), there was a complete disorganisation of the seminiferous cords and the interstitium. In some testes, hyaline degeneration of the seminiferous cords was observed. No cell proliferation was evident, and the epididymal morphology was apparently unaffected. Therefore, parathion seems to interfere with normal testicular differentiation. However, in spite of interstitial damage, the epididymal development seems unaltered. Since the epididymis is an androgen-dependent organ, it may be postulated that testosterone production is still sufficient to support epididymal development but not spermatogenic cell line differentiation.

Allantois↗
PubMed1997

Morphological and histochemical changes in the epididymis of hamsters (Mesocricetus auratus) subjected to short photoperiod.

The morphological involution and histochemical changes of the Syrian hamster (Mesocricetus auratus) epididymis induced by a short light period were investigated. Under short-day conditions, the epididymis showed marked morphological changes including a decrease in luminal diameter, disappearance of spermatozoa, increase of interductal tissue, increase of intraepithelial lipofuscin deposits, the presence of phagolysosomes in the principal cells and macrophage-like cells, and a considerable modification of most clear cells. With lectin histochemistry changes were found in the glycoconjugates of principal cells of the regressed epididymis, either a decrease (PNA, WGA, HPA and DBA) or an increase (MAA) in the affinity of lectins to the Golgi area, or a decrease (HPA) or an increase (PNA) in lectin binding to stereocilia. Both morphological and histochemical results showed that, under this light condition, the cauda epididymidis presented the most prominent alterations, and that the epididymis showed increased absorptive activity and a decreased synthesis of glycoproteins. All these changes are probably due to the decrease in testosterone levels.

Animals↗
PubMed1995

Photoperiod-induced changes in the proteins secreted by the male genital tract of the rodent Octodon degus.

The proteins secreted by the male genital tract were analyzed in the seasonally breeding rodent Octodon degus. The protein patterns from the fluids collected from sexually active animals were compared with those from animals in resting period, with others which were previously castrated, and with castrated animals which received testosterone replacement treatment. Fluids from cauda epididymides (CE), seminal vesicles (SV) and prostate glands (PG) were collected, and analyzed by polyacrylamide gel electrophoresis followed by different staining methods and densitometry. Modifications were detected in the protein patterns of resting or castrated animals. In CE fluid, the decrease of one protein band (45 Kda) and the uprising of another (210 Kda) were recognized after castration. In animals during resting period the changes were not as marked as in castrated animals. SV secretion demonstrated a similar response to resting phase and castration, because Protein SVS I (200 Kda) decreased or were not observed when these conditions occurred. PG fluid proteins were also modified after castration. In general, the more severe changes in the protein spectrum were induced by castration, despite radioimmunoassay showing that testosterone fall is even higher in resting period animals than in those castrated. Testosterone replacement resulted in recovery of a protein profile which is very similar to that of sexually active males. Results suggest that the androgenic control of male tract secretions would be rather different in this seasonal hystrichomorph when compared to the regulation system described for myomorph rodents.

Animals↗