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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

Effect of three cryoconservation diluents on sperm motility and vitality in the ejaculate of bulbourethal-ectomized llamas (Lama glama), department of La Paz

Maceda Tintaya, Edwin Eddy 01 January 2008 (has links) (PDF)
The purpose of this study was to evaluate the effects of three different diluents used during the cryopreservation process on the motility and vitality of sperm cells. The three diluters used in this study were: A) trice-serum-egg yolk-glycerin, B) serum-egg yolk-glycerin, and C) Dulbecco’s serum-egg-yolk- glycerin. Diluters were tested in proportions of 64-15-15-6% (N1), 54-20-20-6% (N2), and 44-35-15-6% (N3). Llama semen was collected at the Mejoramiento Genético y Diagnóstico Clínico Del Servicio Agropecuario (SEDAG) in the Los Andes Province of the Department of La Paz. The procedure took place at the Unidad Académica Campesina de Tiahuanaco by a direct optimized bulbourethral collection method with an artificial vagina.
312

Metabolomics of Human Semen: A Review of Different Analytical Methods to Unravel Biomarkers for Male Fertility Disorders

Blaurock, Janet, Baumann, Sven, Grunewald, Sonja, Schiller, Jürgen, M. Engel, Kathrin 05 December 2023 (has links)
Background: Human life without sperm is not possible. Therefore, it is alarming that the fertilizing ability of human spermatozoa is continuously decreasing. The reasons for that are widely unknown, but there is hope that metabolomics-based investigations may be able to contribute to overcoming this problem. This review summarizes the attempts made so far. Methods: We will discuss liquid chromatography–mass spectrometry (LC-MS), gas chromatography (GC), infrared (IR) and Raman as well as nuclear magnetic resonance (NMR) spectroscopy. Almost all available studies apply one of these methods. Results: Depending on the methodology used, different compounds can be detected, which is (in combination with sophisticated methods of bioinformatics) helpful to estimate the state of the sperm. Often, but not in all cases, there is a correlation with clinical parameters such as the sperm mobility. Conclusions: LC-MS detects the highest number of metabolites and can be considered as the method of choice. Unfortunately, the reproducibility of some studies is poor, and, thus, further improvements of the study designs are needed to overcome this problem. Additionally, a stronger focus on the biochemical consequences of the altered metabolite concentrations is also required
313

Cryopreservation of microencapsulated bovine spermatozoa

Pandolfi, Susan M. 01 November 2008 (has links)
The ultimate design of a microencapsulated AI dose is to continuously release sperm over a period of time in the female reproductive tract, thus alleviating the need for estrus detection. The objective of Trial 1 was to determine in vitro sperm release times for three microcapsule membranes. Semen was collected from four bulls, pooled, extended in 20% egg yolk TEST to a concentration of 80 = 10⁶ cells/ml, and encapsulated. Microcapsule membranes were constructed from isomers of polylysine: .1% poly-L-lysine (PLL), .1% poly-D-lysine (PDL), and a 50:50 mixture of the isomers (PLPD). Microcapsules were incubated at 37°C in a buffer containing .5% heparin or .5% trypsin and evaluated at 0.5, 1, 2, 4, 8, and 16 h post-encapsulation. For sperm encapsulated there were no significant differences in sperm motility. However, peak time of maximum sperm release differed between PLL and PDL membranes at 2 and 4 h of incubation. In Trial 2, sperm viability and microcapsule membrane stability were assessed post-thaw using PLL or PDL, two encapsulating temperatures (5°C or 23°C) and two times of glycerol addition (prior or post encapsulation at 5°C). Semen was extended to 80 = 10⁶ cells/ml and encapsulated. Capsules from all treatment combinations were incubated in .5% trypsin and evaluated as in Trial 1. In addition, motility was estimated at 1, 3, 6, and 9 h post-thaw. Motility from the unencapsulated control and capsules with glycerol addition prior to encapsulation, was superior (P < .05). Additionally, sperm release from capsules prepared at 5°C with glycerol addition post encapsulation was greater than all other treatments (P < .05). Time of peak sperm release for capsules was similar to the previous trial. There was a positive correlation between average capsule diameter and sperm release for both trials (P < .05). These data suggest that a combination of PLL and PDL capsules may complement each other in timing of sperm release and may be utilized in an inseminate mixture for extending the effective release in the female / Master of Science
314

Effect of high and low dosage of fresh and frozen semen on accessory sperm number, fertility and embryo quality in artificially inseminated cattle

Nadir, Sher 22 October 2009 (has links)
This study was designed to : 1) Determine the effects of fresh vs frozen semen at a high inseminate dosage (lOOxl06sperm) contrasted to their effects at a conventional dosage (20xl06 sperm) on accessory sperm per ovum and 2) Evaluate the relationship between accessory sperm number per embry%vum and fertilization status/embryo quality if accessory sperm number were affected by treatment. In this study semen from four bulls routinely giving a minimum of 700/0 morphologically normal and 600/0 motile sperm cells were used. Ejaculates of these bulls were split and prepared for use as fresh and frozen semen at either 100xl06 or 20xI06 cells per dose in.5 mL French straws. Half of the total semen filled straws were frozen in liquid nitrogen at -196°C and half were stored at 5°C for 4 days after collection and used as unfrozen. Cows in standing heat were inseminated with fresh or frozen semen at either high (IOOxl06 sperm) or conventional dose (20xl06 sperm). Ova/embryos were recovered non surgically on day 6 after breeding. Accessory sperm were counted in the recovered embryos/ova after partial digestion with Pronase followed by compression of the embryo/ovum with a cover slip. From 129 inseminations to normally cycling cows, 98 embryos/ova were recovered. To reduce male effects, embryos/ova used were randomly balanced across treatments, by ejaculate within bull for evaluation of frozen vs fresh semen (n = SO) and by bull for evaluation of high vs low dosage treatments (n = 76). No difference (P > 0.05) in accessory sperm was observed for fresh vs frozen semen at either the high or low dosage. The mean accessory sperm values for fresh high dose (n=21), frozen high dose (n=21), fresh low dose (n= 19), and frozen low dose (n= 19) were 26.S1±30.23 (SD), 36.05±44.74 (SD), 29.37± 55.97 (SD) and 30.l6± 70.18 (SD) respectively. When data for embryos/ova resulting from fresh and frozen semen were pooled within dosage, a significant difference was observed between the median accessory sperm values for high and low doses of semen (P < .05). Mean ± SD and median values for accessory sperm were: 37.8± 38.3 and 27.5; 28.9± 62.8 and 3.0, for the high and low dose, respectively. Increasing accessory sperm number by the higher dosage improved the fertilization status/embryo quality (P < .05). Percentage unfertilized ova, degenerate embryos and embryos classified poor to fair and good to excellent were: 3, 5, 24, 68; and 21, 16, 18, 45, for the high and low dose, respectively. Overall, embryos/ova classified good to excellent, poor to fair, degenerate and unfertilized had median accessory sperm values of 18, 9.5, 5.5 and 0, respectively. However, the lack of accessory sperm in unfertilized ova was significantly different from excellent-good quality embryos (P < .05). / Master of Science
315

The Effect of Poly-L-Lysine Concentration, Molecular Weight, and Encapsulation Temperature on Microencapsulated Bovine Spermatozoa

Fultz, Stanley Wakefield 29 July 2013 (has links)
A series of in vitro studies were conducted to evaluate the effect of poly-l-lysine concentration, molecular weight, and encapsulation temperature on the post encapsulation survivability of spermatozoa. Viability of spermatozoa encapsulated at 2012 C using four poly-l-lysine concentrations (.05%, .15%, .25%, and .35%) did not differ over the 8 h incubation period. However, the viability of each of the four treatments was lower than that of the unencapsulated control (p<.05 and p<.01; percentage motility and percentage intact acrosomes, respectively), indicating spermatozoal damage occurred during the encapsulation process. Capsule wall thickness and integrity for the .15%, .25%, and .35% concentrations were greater (p<.Ol) than that of the .05% capsules. / Master of Science
316

Experiments to improve the quality of sex-sorted fresh and frozen porcine spermatozoa / Experimente zur Verbesserung der Qualität von gesextem und tiefgefrorenem Ebersperma

Großfeld, Rudolf 16 May 2007 (has links)
No description available.
317

Improvements in the viability and fertilizing integrity of boar spermatozoa using the "umqombothi" sorghum bicolour semen extenders

Pitso, Teele January 2009 (has links)
Thesis (M. Tech. (Agric. Animal Prod.)) -- Central University of technology, Free State, 2009 / The objective of this study was to evaluate the viability of semen extended in “Umqombothi” (UMQ) and compare with Beltsville Thawing Solution (BTS) and unextended semen (UNX). Twelve large white boars and twelve large white sows were used in this experiment. The following sperm characteristics were measured; sperm motility percentage, live sperm, sperm concentration, abnormal sperm percentage and semen pH of (UNX), (UMQ) and (BTS) and compared, fertility parameters namely; non-return rate percentage, farrowing rate, total piglets and live piglets were also measured and compared. The results from the study showed a significant difference (p<0.05) in sperm motility between (UNX), (UMQ) and (BTS) whereby (UMQ) had the highest percentage of motile sperm which was followed by (BTS) and (UNX) having the lowest percentage of motile sperm, however the results also showed that sperm motility and live sperm percentage of semen stored at 4°C differed significantly (p<0.05) from sperm motility and live sperm percentage of semen stored at 25°C whereby sperm motility and live sperm percentage of semen stored at 25°C were higher than sperm motility and live sperm percentage of semen stored at 4°C. Nevertheless no significant difference in sperm concentration and semen pH was found when semen stored at 4°C and 25°C were compared. However were time of semen collection of 9:00 and 15:00 were compared no significant differences in sperm motility percentage, live sperm percentage, sperm concentration, abnormal sperm percentage and semen pH were observed. The study also revealed a significant difference (p<0.05) in non-return rate, farrowing rate, total piglets and live piglets between semen stored at 25°C and 4°C of which the results explain that semen stored at 25°C had a higher percentage of non-return rate , farrowing rate, total piglets and live piglets, however, Under (UNX) collected at 9:00 and 15:00 that there was no significant difference in no-return rate percentage, farrowing rate, total piglets and live piglets was observed when two times of semen collections were compared. Under (UMQ) collected at 9:00 and 15:00 there was also no significant difference in non-return rate percentage, farrowing rate, total piglets and live piglets observed when two times of semen collections were compared. Under (BTS) collected at 9:00 and 15:00 there was also no significant difference in non-return rate percentage, farrowing rate, total piglets and live piglets observed when two times of semen collections were compared. Nevertheless were semen extenders were compared (UNX) collected at 9:00 and 15:00 differed significantly (p<0.05) from (UMQ) and (BTS) collected at 9:00 and 15:00 whereby (UNX) had the lowest percentage of non-return rate, farrowing rate, total piglets and live piglets.
318

Predictive value of normal sperm morphology in intrauterine insemination (IUI) : a structured literature review

Van Waart, J. (Johannes) 12 1900 (has links)
Thesis (MMed)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The aim of the study was to conduct a structured review of the literature published on the use of normal sperm morphology, as an indicator of male fertility potential in intrauterine insemination (M) programs. Published literature in which normal sperm morphology was used to predict pregnancy outcome in lUI during the period 1984 - 1998 was reviewed. Four hundred and twenty one articles were identified. Eighteen provided data that could be tabulated and analyzed. Eight of the analyzed studies provided sufficient data for statistical analysis. Six studies used the Tygerberg strict criteria and two the WHO guidelines (1987, 1992). A meta-analysis of the six studies in the strict morphology group yielded a risk difference (RD) between the pregnancy rates achieved in the patients below and above the 4% strict criteria threshold of -0.07 (95% CI: -0.11 to -0.03; p< 0.001). WHO criteria group (1987,1992) had insufficient data to be analysed. Meta-analysis showed a significant improvement in pregnancy rate above 4% threshold for strict criteria. Accurate evaluation of normal sperm morphology results should be an integral part of evaluating the male factor. / AFRIKAANSE OPSOMMING: Die doel van die studie was om 'n gestruktureerde literatuuroorsig van die gepubliseerde data oor normale sperm morfologie uit te voer om vas te stelof dit enige waarde het as voorspeller van manlike fertiliteitspotensiaal in intra uteriene inseminasie (lUI) programme. Gepubliseerde literatuur waar normale sperm morfologie gebruik IS om swangerskapsuitkoms te voorspel met IUI in die tydperk 1984 - 1998 is nagegaan. Vierhonderd een en twintig artikels is geïdentifiseer. Agtien het genoeg data gehad om te kan tabuleer en analiseer. Agt van die geanaliseerde studies het voldoende data gehad vir statistiese analise. Ses studies het die Tygerberg streng kriteria gebruik en twee die WGO (1987, 1992) riglyne. 'n Meta-analise van die ses studies in die streng kriteria groep het 'n risiko verskil tussen swangerskapstempo in pasiënte onder en bo die 4% streng kriteria afsnypunt, van -0,07 (95% betroubaarheidsindeks: -0.11 tot -0.03; p<O.OOl) getoon. Die WGO kriteria (1987,1992) groep het onvoldoende data gehad om te kan analiseer. Meta-analise het 'n bekenisvolle verbetering in swangerskapuitkoms bo die 4% afsnypunt getoon vir die streng kriteria. Akkurate evaluasie van normale sperm morfologie resultate behoort 'n integrale deel te wees van die proses om die manlike faktor in infertilteitsbehandeling volledig te evalueer.
319

Effects of insulin and leptin on human spermatozoa function and their cross-talk with nitric oxide and cytokines

Lampiao, Fanuel 12 1900 (has links)
Thesis (PhD (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: In recent years there has been an increase in obesity and diabetes mellitus (DM). These conditions have for a long time been associated with infertility. Obesity is characterized by high levels of circulating leptin and cytokines as well as insulin resistance. Type I DM is associated with low or no insulin whereas, Type II DM is characterised by insulin resistance. As the prevalence of obesity and DM continues to rise, it is likely that the incidence of infertility associated with these pathological conditions will likewise increase. The effects of insulin and leptin on male reproductive function have been reported on the endocrine and spermatogenesis level, but their effects on cellular level of human ejaculated spermatozoa are yet to be elucidated. This study presents data on the role of insulin and leptin on human ejaculated spermatozoa and their interaction with cytokines and nitric oxide. In the first part of the study, we established the suitable concentrations of glucose, insulin and leptin that could be administered to human spermatozoa in vitro. Glucose concentration of 5.6 mM was chosen as the suitable concentration to be administered to human spermatozoa because it has previously been reported in the literature; furthermore, it is within the range of the physiological glucose levels found in the blood of fasting humans. Insulin and leptin concentrations of 10 μIU and 10 nmol were chosen respectively because they gave much improved sperm function and this was within the range of insulin and leptin levels previously measured in human ejaculated spermatozoa. This was followed by investigating the signalling pathway of insulin and its beneficial effects on human spermatozoa function. Endogenous insulin secretion from human ejaculated spermatozoa was blocked by nifedipine and its receptor tyrosine phosphorylation effects were inhibited by erbstatin while phosphatidylinositol 3-kinase (PI3K) phosphorylation activity was inhibited by wortmannin. Exogenous insulin administration significantly increased human sperm motility parameters as well as the sperm ability to acrosome react. The inhibition of endogenous insulin release from spermatozoa as well as the inhibition of the insulin receptor substrate (IRS) tyrosine phosphorylation significantly decreased motility parameters and the ability of spermatozoa to acrosome react. The study also investigated the effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production. Both insulin and leptin significantly increased sperm motility parameters, acrosome reaction and NO production. The NO production induced by insulin and leptin was via PI3K signalling as evidenced by a reduction in NO levels when PI3K activity was inhibited by wortmannin. To investigate whether insulin and leptin could improve motility parameters of asthernozoospermic and teratozoospermic spermatozoa, the spermatozoa were separated into two fractions by means of a double density gradient technique. The gradient system was able to separate spermatozoa into high morphologically abnormal and less motile spermatozoa similar to that of asthernozoospermic and teratozoospermic patients as well as a more motile fraction. Insulin and leptin significantly increased the motility parameters of spermatozoa from the immature and less motile fraction. The fourth part of the study was aimed at investigating the effects of the cytokines, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), on human sperm motility, viability, acrosome reaction and NO production. The study shows that TNF-α and IL-6 significantly reduced motility parameters and acrosome reaction in a dose4 and time-dependent manner. These cytokines were also shown to significantly increase NO production from human spermatozoa. The decreased motility parameters induced by these cytokines could be attributed to their ability to induce excessive NO production. It is not yet clear how they inhibit spermatozoa to undergo the acrosome reaction. The fifth part of the study was to investigate the expression and localization of glucose transporter 8 (GLUT8) in human spermatozoa. This study shows that GLUT8 is constitutively expressed and located in the midpiece region of the human spermatozoa. The study also showed that stimulating spermatozoa with insulin led to an increase in GLUT8 expression as well as translocation to the acrosomal region. In the last part of the study we wanted to investigate why the increase in NO generation by spermatozoa due to insulin and leptin stimulation is accompanied with increased sperm function whereas NO increased due to TNF-α and IL-6 stimulation is accompanied with decreased sperm function. We observed that TNF-α and IL-6 not only increased NO production but also ROS production. This study speculates that the decrease in sperm motility and acrosome reaction when TNF-α and IL-6 were administered was due to the concomitant high increase in NO and ROS they induced. In conclusion, this study has established in vitro beneficial effects of insulin and leptin in normozoospermic and asthernozoospermic human sperm function. These hormones influence sperm function via the PI3K signalling pathway in two ways. Firstly, by increasing GLUT8 expression and translocation thereby possibly increasing glucose uptake and metabolism and secondly, by increasing NO production. The study has also established that TNF-α and IL-6 have detrimental effects on human spermatozoa in a dose and time dependent manner. These effects are mediated via their ability to stimulate both NO and ROS production in human spermatozoa. This study reports that GLUT8 is expressed in the midpiece region of human spermatozoa and that insulin stimulation upgrades its expression and leads to its translocation to the acrosomal region. / AFRIKAANSE OPSOMMING: Oor die afgelope jare was daar `n toename in obesiteit en diabetes mellitus (DM). Hierdie toestande word reeds vir ’n geruime tyd geassosieer met onvrugbaarheid. Obesiteit word gekenmerk deur verhoogde sirkulerende vlakke van leptiene en sitokiene sowel as insulien weerstandigheid. Tipe I DM word geassosieer met lae of geen insulien terwyl Tipe II DM gekenmerk word deur insulien weerstandigheid. Soos wat die voorkoms van obesiteit en DM toeneem, is dit waarskynlik dat die insidensie van onvrugbaarheid wat met hierdie patologiese toestande geassosieer word, gevolglik ook sal toeneem. Die effek van insulien en leptien op die manlike voortplantingsfunksie is alreeds aangetoon op endokriene en spermatogenese vlak, maar hul effekte op sellulêre vlak van menslike geëjakuleerde spermatosoë is nog onduidelik. Die studie vertoon data oor die rol van insulien en leptien op die menslike geëjakuleerde spermatosoë en hul interaksie met sitokiene en stikstofoksied (NO). In die eerste gedeelte van die studie, het ons ’n toepaslike konsentrasie van insulien en leptien bepaal wat aan menslike spermatosoë in vitro toegedien kan word. Glukose konsentrasies van 5,6 mM is bepaal as die gepaste konsentrasie om aan menslike spermatosoë toe te dien, omdat dit beter resultate tot gevolg het; verder is dit vergelykbaar met fisiologiese glukose vlakke in die bloed van `n vastende persoon. Insulien en leptien konsentrasies is op 10 μIU en 10 nm onderskeidelik vasgestel, aangesien dit tot beter resultate gelei het, en omdat dit vergelykbaar was met insulien en leptien vlakke wat reeds voorheen in menslike geëjakuleerde spermatosoë gemeet is. Dit was gevolg deur `n ondersoek na die insulien seintransduksie pad en sy voordelige effekte op menslike spermatosoë funksie. Endogene insulien afskeiding deur menslike geëjakuleerde spermatosoë was deur nifedipien geïnhibeer en sy reseptor tirosien fosforilasie effekte was deur erbstatin geïnhibeer terwyl fosfatidielinositol 3-kinase (PI3K) fosforilasie deur wortmannin geïnhibeer is. Eksogene insulien toediening het menslike sperm-motiliteit parameters betekenisvol laat toeneem asook die vermoë van sperme om die akrosoomreaksie te ondergaan. Die inhibisie van endogene insulien afskeiding deur spermatosoë sowel as die inhibisie van die insulien reseptor substraat (IRS) tirosien fosforilasie het die motiliteit parameters en die akrosoomreaksievermoë van spermatosoë verlaag. Die studie het ook die effekte van insulien en leptien op menslike sperm-motiliteit, -lewensvatbaarheid, -akrosoomreaksie en -NO produksie nagevors. Beide insulien en leptien het sperm-motiliteit parameters, -akrosoomreaksie en -NO produksie betekenisvol verhoog. NO produksie is deur insulien en leptien via PI3K seintransduksie geïnduseer, soos bewys deur die verlaging waargeneem in NO vlakke toe PI3K aktiwiteit deur wortmannin geïnhibeer was. Om vas te stel of insulien en leptien die motiliteit parameters van asthenozoospermiese en teratozoospermiese spermatosoë kon verbeter, het ons spermatosoë in twee fraksies met ’n dubbel digtheid gradiënt geskei. Die gradiënt sisteem was daartoe instaat om die spermatosoë in ’n onvolwasse, (morfologies abnormaal en minder motiel - soortgelyk aan dié van asthenozoospermiese en teratozoospermiese pasiënte), sowel as ’n volwasse meer motiele fraksie te skei. Insulien en leptien het die motiliteit parameters van spermatosoë van die onvolwasse en minder motiele fraksie verhoog. Die vierde gedeelte van die studie was daarop gemik om die effekte van die sitokiene tumor nekrose faktor alfa (TNF-α) en interleukin-6 (IL-6) op menslike sperm-motiliteit, -lewensvatbaarheid, -akrosoomreaksie en -NO produksie, te ondersoek. Die studie het getoon dat TNF-α en IL-6 motiliteit parameters en akrosoomreaksie in ’n tyd- en dosis-afhanklike wyse betekenisvol verlaag het. Hierdie sitokiene was ook in staat om NO produksie in menslike spermatosoë te verhoog. Die verlaging in motiliteit parameters wat deur hierdie sitokiene geïnduseer is, kan toegeskryf word aan hul vermoë om die produksie van oormatige hoeveelhede NO te stimuleer. Dit is nog nie duidelik hoe hulle die akrosoomreaksie in spermatosoë kan inhibeer nie. Die vyfde gedeelte van die studie het dit ten doel gehad om die uitdrukking en lokalisering van die glukose transporter 8 (GLUT8) in menslike spermatosoë te ondersoek. Hierdie studie kon aantoon dat GLUT8 konstitutief uitgedruk is en in die middelstuk van die menslike spermatosoë voorkom. Die studie bewys ook dat stimulering van die spermatosoë met insulien tot `n toename in GLUT8 uitdrukking sowel as translokasie na die akrosomale area, lei. In die finale gedeelte van die studie wou ons ondersoek waarom die toename in NO produksie in spermatosoë (as gevolg van insulien en leptien stimulasie) deur `n toename in spermfunksie gekenmerk word, terwyl die toename in NO produksie (as gevolg van TNF-α en IL-6 stimulasie) deur ’n afname in spermfunksie gekenmerk word. Ons het waargeneem dat TNF-α en IL-6 nie alleen NO produksie nie, maar ook reaktiewe suurstof spesies (ROS) produksie verhoog het. Ons vermoed dat die afname in sperm motiliteit en akrosoomreaksie met TNF-α en IL-6 toediening, die gevolg van die gelyktydige verhoging in NO en ROS was. In gevolgtrekking kan ons sê dat hierdie studie die voordelige in vitro effekte van insulien en leptien op asthenozoospermiese en teratozoospermiese menslike spermfunksie aangetoon het. Hierdie hormone beïnvloed spermfunksie via die PI3K seintransduksie pad op twee maniere. Eerstens, deur `n toename in GLUT8 uitdrukking en translokasie, met die gevolg dat glukose opname en metabolisme moontlik verhoog is, en tweedens, deur die toename in NO produksie. Die studie het ook vasgestel dat TNF-α en IL-6 nadelige effekte op menslike spermatosoë in `n dosis- en tyd-afhanklike wyse het. Hierdie effekte vind plaas a.g.v. hul vermoë om beide NO en ROS produksie in menslike spermatosoë te induseer. Die studie toon aan dat GLUT8 uitdrukking in die middelstuk van die menslike spermatosoon voorkom en dat insulien stimulasie GLUT8 uitdrukking opreguleer en tot translokasie na die akrosomale area lei.
320

The interaction between human spermatozoa and its homologous zona pellucida : scientific advances and clinical significance

Oehninger, Sergio C. 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Infertility is a very common problem worldwide. Recent data have shown that disorders of the male represent the most common single defined cause of infertility. This proposal examines the clinical significance and fundamental physiological aspects of human gamete interaction. These studies are focused on the assessment of the cellular-molecular mechanisms involved in human sperm binding to its homologous zona pellucida resulting in the physiologic induction of the acrosome reaction. We have developed and validated in vitro bioassays that assess specific steps of the fertilization process that are critical for early embryo development. The results of our translational research have already had a significant impact on the overall evaluation of male infertility and on the clinical management of the infertile man in the assisted reproduction arena. Furthermore, the unveiling of the basic mechanisms involved in human gamete interaction will ultimately allow for both (i) the development of new male reproductive diagnostic capabilities and (ii) the design of improved and safer therapies aiding conception in childless couples suffering from male infertility. / AFRIKAANSE OPSOMMING: Menslike onvrugbaarheid is 'n algemene wêreldwye probleem en onlangse data toon aan dat die manlike factor die grootste enkel bydraende factor tot hierdie toestand is. Die werk loods 'n intensiewe ondersoek na die kliniese betekenis en basiese fisiologiese aspekte wat 'n rol tydens spermsel en eisel interaksie speel. Hoofstuk 3 fokus op die sellulêre en molekulêre meganismes wat betrokke is tydens spermsel en eisel binding wat gevolglik lei tot akrosoomreaksie van die spermsel. Die werk verteenwoordig die resultate van 10 jaar se navorsing tussen die kandidaat en die promoter. Dit gee oorsprong aan 'n reeks bio-toetse wat die bevrugtingsproses koriografiese ontleed en verskaf dus 'n stap-vir-stap uiteenseting van menslike bevrugting en gevolglike embrio ontwikkeling. Die resultate in Hoostuk 4 bring vernuwing in die begrippe van die manlike faktor en die rol in die kinderlose huwelik. Die resulate soos in Hoofstuk 3 en 4 uiteengesit, vorm nie net die basis vir die moontlike ontwikkeling van nuwe diagnostiese benaderings tot die hantering van die man nies maar speel oojk 'n rol die daarstelling van verbeterde terapeutiese hantering van die kinderlose egpaar. Hoofstuk 5 gee kortliks riglyne en aanbevelings tot opsigte van die gebruik van die spermsel-zona pellucida bindingstoets en akrosomreaksie. Die kandidaat bevel aan dat die genoemde twee bio-toetse deel van die laboratorium ondersoeke van die man gebruik moet word.

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