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Biomedical subjects

D Vantman

Publications and source records attributed to D Vantman.

18 recordsLinked to original sources
PubMed1999

Sperm penetration through the human zona pellucida as a predictor of in vitro fertilization.

The aim of this study was to determine the predictive value of sperm penetration into the perivitelline space of human cadaveric oocytes on in vitro fertilization outcome. Forty-two patients with tubal infertility undergoing ovarian stimulation with gonadotropin for in vitro fertilization and embryo transfer participated in the study. The number of spermatozoa bound to the human zona pellucida, the percentage of cadaveric oocytes with one or more spermatozoa in the perivitelline space, and the in vitro fertilization outcome were evaluated. Spermatozoa from 37 of 42 patients were able to penetrate the perivitelline space of cadaveric oocytes as well as to fertilize human oocytes in vitro. In three individuals, no penetration of the perivitelline space of cadaveric oocytes was observed and no in vitro fertilization was detected. Only two patients were able to fertilize the couple's oocytes without penetration of the cadaveric oocytes. Based on these results the specificity and the sensitivity of the assay to predict in vitro fertilization was 100% and 94.1%, respectively. Accordingly, these results suggest that sperm-zona penetration is a useful bioassay to predict male fertility potential in IVF outcome.

Female↗
PubMed1998

Presence of angiotensin II and expression of angiotensin II type-2 receptor in human fallopian tube.

OBJECTIVE: To determine the presence of angiotensin II and angiotensin II type-2 receptor subtype messenger RNA (mRNA) in human fallopian tube. DESIGN: Frozen fallopian tubes were used for all studies. SETTING: Procedures were performed at the Institute of Maternal and Child Research, School of Medicine, University of Chile and San Borja-Arriarán Clinical Hospital, National Health Service, Santiago, Chile. PATIENT(S): Eight patients (30-38 years) undergoing surgical sterilization or hysterectomy for benign gynecologic conditions. INTERVENTION(S): Surgery was scheduled in the proliferative or secretory stage of the menstrual cycle. MAIN OUTCOME MEASURE(S): Localization of angiotensin II by immunofluorescence studies, expression of angiotensin II type-2 receptor mRNA, and concentrations of angiotensin II receptor subtypes and binding characteristics. RESULT(S): Angiotensin II was immunolocalized mainly in blood vessel endothelium and, to a lesser extent, in stromal cells. Both binding and angiotensin II type-2 receptor mRNA were detected at high levels. No differences were seen in receptor concentration, dissociation constants or median inhibitory concentration in fallopian tubes ipsilateral or contralateral to the corpus luteum. CONCLUSION(S): Angiotensin II and angiotensin II receptor are present in human fallopian tube. Angiotensin II type-2 receptor was the main receptor subtype. These results suggest that the renin-angiotensin system may play a regulatory role in functions of the fallopian tube.

Adult↗
PubMed1998

[Contribution of chromosomal abnormalities to in vitro fertilization failures].

BACKGROUND: Present knowledge of mechanisms involved in human fertilization has uncovered a new group of pathologic conditions that have been generically named fertilization abnormalities. AIM: To determine the contribution of chromosomal alterations to in vitro fertilization failures. MATERIALS AND METHODS: A cytogenetic analysis of oocytes that were not fertilized after insemination with normal spermatozoa. Oocytes were obtained from patients subjected to in vitro fertilization in a public hospital of Metropolitan Santiago. Ovulation was induced in these patients administering GnRh-a, FSH, HMG and HCG. The double fixation technique described by Wramsby was used to obtain chromosomes. RESULTS: One hundred and seven oocytes coming from 45 women aged 25 to 42 years old were studied. The frequency of aneuploidy in these oocytes was 37.3%, with a 11.8% of hypohaploidy, a 21.6% of hyperhaploidy and a 3.9% of diploid oocytes. In hyperhaploid as well as in hypohaploid oocytes, the chromosomes involved in aneuploidy pertained to groups D. and G. CONCLUSIONS: Although the total frequency of aneuploidy is within normal ranges, the frequency of hyperhaploidy is superior to previous reports. An explanation for this finding could be that the occurrence of a lack of disjunction with chromosomal retention in the parental cell occurs with a higher frequency than that in which the chromosomes are retained in the polocyte. We also suggest that oocyte chromosomal aneuploidy could contribute to the failure of in vitro fertilization procedures.

Adult↗
PubMed1998

[Severe ovarian hyperstimulation syndrome: an intensive care disease].

Ovarian hyperstimulation syndrome is a severe and potentially fatal iatrogenic disease that affects 2% of women subjected to pharmacological induction of ovulation. The newest data on the clinical picture, risk factors, pathophysiology and management of this disease, are reviewed.

Female↗
PubMed1997

Regulatory role of angiotensin II on progesterone production by cultured human granulosa cells. Expression of angiotensin II type-2 receptor.

The role of angiotensin II (AngII) in ovarian steroidogenesis is not clearly understood. In order to study its action on progesterone synthesis and to determine which receptor subtype is involve, granulosa cells obtained from women undergoing in-vitro fertilization were cultured for 2 or 4 days and then incubated in the presence of AngII (10(-7) M) with or without human chorionic gonadotrophin (HCG, 10 IU/ml) for 3 or 18 h. In cells cultured for 2 days, incubation with AngII decreased progesterone secretion by 36%, and inhibited activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) by 87% (P < 0.05), although its expression was not significantly reduced. However, in cells cultured for 4 days, progesterone production was enhanced by incubation with AngII (38%), and no change was observed in 3 beta-HSD expression. Both inhibitory and stimulatory effects were dose-dependent. Progesterone secretion was increased (93%) by incubation with HCG of cells cultured for 4, but not for 2 days, and no potentiation was observed with AngII. Treatment with PD123177 completely blocked the action of AngII and decreased the HCG-stimulated secretion of progesterone by 27%. Angiotensin type-2 (AT2) receptor mRNA was expressed in cells cultured for 4 days. In conclusion, AngII showed a regulatory role in in-vitro progesterone production by human granulosa luteinized cells, modulating the activity of 3 beta-HSD. It is likely that these actions may be mediated via membrane receptors, possibly of the AT2 receptor family.

Angiotensin II↗
PubMed1996

Total antioxidant capacity of human seminal plasma.

Although the importance of seminal plasma in the protection of spermatozoa against reactive oxygen species is well known, only a few studies have investigated its antioxidative properties and the possible relationship between infertility and plasmatic antioxidant defences. The aim of the present study was to assess the status of the total non-enzymatic antioxidant defences of human seminal plasma. Semen samples were obtained from 101 patients consulting for infertility and 15 fertile donors. A total reactive antioxidant potential (TRAP) in seminal plasma was determined by luminol-chemiluminescence. The relationship of seminal TRAP values to lipid peroxidation was also evaluated. Our results show that semen samples from fertile controls show total antioxidant capacity at higher frequency and value than equivalent samples from suspected subfertile men. This fact as well as the inverse relationship observed between antioxidant capacity and lipid peroxidation potential strongly suggest that impaired antioxidant defences may play a role in infertile disorders.

Antioxidants↗
PubMed1994

[Variability of seminal analysis and of objective parameters of sperm motility in semen during sperm capacitation in subjects with proved fertility].

We studied the variability of traditional semen analysis parameters as well as sperm motion characteristics analyzed by computer-assisted-semen analyzer in semen and after 2 hours of incubation in capacitation conditions. Twenty men with probed fertility provided three semen samples and 60 men provide one. The higher variability was observed with seminal sperm concentration, the lower variation was observed for percent motility and percent of normal morphology. Ten Oligospermic donors (12,5%) were observed in our population without other semen parameters abnormalities. Their motion characteristics were comparable to cells analyzed from normospermic men. A lower variability of sperm motion characteristics was observed during sperm capacitation compared to sperm movement in seminal plasma; suggesting that sperm motion characteristics during capacitation may be a usefull method additional to semen analysis to evaluate male fertility potential.

Diagnosis, Computer-Assisted↗
PubMed1992

The acrosome reaction-inducing activity of individual human follicular fluid samples is highly variable and is related to the steroid content.

In this study, we have evaluated the relationship between the acrosome reaction-inducing activity of individual human follicular fluid samples and their steroid content. Eighteen samples of follicular fluid were obtained during egg retrieval in six patients undergoing assisted fertilization. Motile spermatozoa were incubated in modified Tyrode's medium (26 mg/ml bovine serum albumin) for 20 h at 1 x 10(7) cells/ml. In a single experiment, aliquots of a semen specimen were simultaneously treated with an aliquot of each follicular fluid sample. The percentage of acrosome reacted spermatozoa was determined using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA) lectin. The fluids were also analysed by radioimmunoassay to determine the levels of progesterone, 17 alpha-hydroxy-progesterone, testosterone and oestradiol. The results showed that there was a positive, highly significant correlation between the acrosome reaction-inducing activity and the progesterone level of each follicular fluid sample (r = 0.72, P less than 0.005). Additionally, treatment of the follicular fluid samples with charcoal-dextran caused both a decrease in progesterone concentration and the total loss of the acrosome reaction-inducing activity. The addition of progesterone restored the acrosome reaction-inducing ability in 88% of samples. These data support the idea that progesterone in follicular fluid is the molecule responsible for inducing the acrosome reaction in human spermatozoa.

Acrosome↗
PubMed1991

Human spermatozoa selected by Percoll gradient or swim-up are equally capable of binding to the human zona pellucida and undergoing the acrosome reaction.

Several techniques have been used for selecting motile spermatozoa including Percoll and albumin gradients, swim-up, and glass wool filtration. A high yield of motile spermatozoa as well as an enhancement of motility are the most desirable features of a practical method. An equally important consideration is whether or not these techniques select functionally normal spermatozoa. In this study we have compared two methods for separation of motile cells, swim-up and Percoll gradient. Normal semen samples from 12 different men were used in this study. Each sample was simultaneously processed by swim-up and Percoll gradient using modified Tyrode's medium. After the sperm concentration was adjusted to 1 x 10(7) spermatozoa/ml, the suspensions were incubated at 37 degrees C, 5% CO2 in air. In each suspension the percentage of sperm recovery, percentage of motile spermatozoa, percentage of acrosome reacted spermatozoa (either spontaneously or stimulated with human follicular fluid), percentage of zona-free hamster oocytes penetrated, and number of spermatozoa bound to the human zona pellucida were determined. The results obtained indicated that the percentage of sperm recovery was higher with the Percoll gradient than with the swim-up procedure (P less than 0.001). However, no significant differences were found between these two sperm populations in the percentage of motile cells, in the percentage of acrosome reacted spermatozoa, and in the percentage of zona-free hamster oocytes penetrated. In addition, the number of spermatozoa bound per zona pellucida was similar for spermatozoa selected by Percoll or swim-up. We conclude that there were no functional differences between the spermatozoa selected by either method.

Acrosome↗
PubMed1989

Follicular fluid-induced acrosome reaction distinguishes a subgroup of men with unexplained infertility not identified by semen analysis.

We compared the ability of sperm to undergo follicular fluid-induced acrosome reaction in vitro in fertile men and patients with unexplained infertility. After capacitation under optimum conditions, 28% of sperm from fertile men undergo acrosome reaction after follicular fluid exposure, whereas only 7% of the cells react spontaneously. In 15 men with unexplained infertility, 6 patients showed lack of acrosome reaction, whereas 9 men had sperm acrosome reactions similar to that of fertile men. However, in this cohort under study, semen characteristics of AR(+) and AR(-) patients were similar. In addition to inducing sperm acrosome reaction, follicular fluid also promoted significant changes in motion characteristics of capacitated sperm. Sperm curvilinear velocity (Vc) increased significantly after exposure to follicular fluid though linearity remained unchanged. The largest difference in cumulative Vc occurred at 90 microns/s. Assessing the ability of capacitated sperm to acrosome react may have clinical significance in predicting whether such sperm are capable of fertilizing an ovum.

Acrosome↗
PubMed1989

Assessment of sperm motion characteristics from fertile and infertile men using a fully automated computer-assisted semen analyzer.

Sperm curvilinear velocity (Vc) and linearity (L) were analyzed in semen from 20 fertile men and from 53 patients with unexplained infertility by a computer-assisted semen analyzer (CASA). Because the frequency distribution of Vc from patient's spermatozoa showed a nongaussian distribution, comparison of mean values of Vc and L between men with unexplained infertility and fertile men is inappropriate. As an alternative, the authors compared the cumulative distribution of the percent of cells measured at increasing intervals of Vc and L, and observed a significant difference between patients and fertile men from the level of Vc30 through Vc70 micron/sec for curvilinear velocity and L2 through L6 for linearity (P less than 0.001). Furthermore, the authors coanalyzed these two parameters at the greatest point of difference (Vc40 and L3) and observed that their patient population can be differentiated into four subpopulations of subjects accordingly to their Vc40 and L3 values. In this study, 43 of the 53 patients had a motility disorder characterized by having a higher percent of cells being substantially slower and less directional than cells from normal men. However, in some patients, motion characteristics were indistinguishable from those in normal men.

Diagnosis, Computer-Assisted↗
PubMed1989

Sperm motion characteristics in men with isolated hypogonadotropic hypogonadism treated with gonadotropin.

The authors compared curvilinear velocity (Vc) and linearity (L) of sperm from fertile oligospermic men with isolated hypogonadotropic hypogonadism (IHH) to Vc and L of sperm from fertile normal men in order to determine if sperm motion analysis is better than sperm density as an indicator of fertility potential. Nine fertile men with IHH treated with exogenous gonadotropins and 20 fertile normal men were studied. Sperm density was significantly lower in the men with IHH compared with normal men (15.5 +/- 4.8 x 10(6)/ml versus 92.4 +/- 9.7 x 10(6)/ml; mean +/- standard error of the mean [SEM]; P less than 0.01) as was percent motility (51.4 +/- 4.7 versus 73.4 +/- 3.1; P less than 0.01). While a small but significant difference in Vc was noted between the groups at the 40 micron/second cumulative distribution point (P less than 0.01), no difference in L was found between the two groups. When the men with IHH were subgrouped according to sperm density (greater than 20 x 10(6)/ml versus less than or equal to 20 x 10(6)/ml, no differences in Vc were found between the subsets, but for L sperm were somewhat less directional for the subgroup with a density less than or equal to 20 x 10(6)/ml (P = 0.05). Coanalysis using both Vc and L parameters indicated that sperm from IHH patients were distributed similarly to sperm from normal men. However, sperm motion characteristics in men with unexplained infertility were different from values measured in normal men and IHH patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Computer-Assisted↗
PubMed1989

Low acrosin activity in a subgroup of men with idiopathic infertility dose not correlate with sperm density, percent motility, curvilinear velocity, or linearity.

The authors compared sperm acrosin activity with sperm density and cell motion characteristics in 21 normal fertile men and 25 patients with unexplained infertility. Under standardized and optimized conditions of abstinence and semen sample processing, we measured sperm acrosin activity in washed sperm from direct aliquots of semen and in aliquots of semen filtered through glasswool to remove dead cells and debris. Using washed sperm from semen, sperm acrosin levels in infertile men (median, 44 microIU/10(6) sperm) were significantly lower than values measured in fertile men (median, 67 microIU/10(6) sperm, P less than 0.01). After glasswool filtration, sperm acrosin activity was higher for both fertile and infertile men. Using washed sperm, 7 of 25 patients had acrosin activity consistently below values measured for fertile men; after glasswool filtration, values for 8 of 14 patients were below the normal range. For either fertile or infertile men, sperm acrosin activity showed no correlation with sperm density, percent motility, or either motion characteristic of curvilinear velocity (Vc40 microns/sec) or linearity (L3); and further, the low sperm acrosin activity of some infertile patients did not correlate with the motion co-characteristics measured at Vc40/L3, and the majority of patients with slower and/or less directional sperm had normal acrosin activity. From our data, we therefore conclude that sperm acrosin activity is independent of sperm motion characteristics.

Acrosin↗
PubMed1988

Computer-assisted semen analysis: evaluation of method and assessment of the influence of sperm concentration on linear velocity determination.

Semen samples from 77 men were used to estimate the accuracy and precision of measurements of sperm density, percent motility, and motion characteristics using a new, fully automated, computer-assisted semen analyzer (CASA). Results are compared with traditional semen analysis methodology. Acceptable precision for count and percent motility was obtained using three to nine random fields of observation when there were more than 10 cells per high-power microscopic field. A highly significant correlation (P less than 0.01) was found between the two methods in the assessment of sperm concentration and percent motility, but CASA overestimated concentration significantly (P less than 0.01) by about 30% when there were less than 60 cells per high power field. This overestimation seemed to be due to the number of nonsperm particles in semen that are confused with spermatozoa by the program. Linear velocity determination was influenced by the number of tracking points as well as by the concentration of cells present in the counting chamber. More representative linear velocity estimations in semen were obtained when sperm concentration was less than 40 x 10(6) cells/ml and 20 tracking points were used in the determination. For semen specimens containing higher cell density, sperm concentration needed to be reduced by diluting the semen with the patient's own sperm-free seminal plasma before measuring motion characteristics.

Computers↗