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Biomedical subjects

N A Klein

Publications and source records attributed to N A Klein.

At least 19 recordsLinked to original sources
PubMed2006

Ovulation detection methods for urinary hormones: precision, daily and intermittent sampling and a combined hierarchical method.

BACKGROUND: We evaluate the performance of ovulation detection methods and present new approaches, including evaluation of methods for precision, combining multiple markers into a hierarchical system and using ovulation markers in intermittent sampling designs. METHODS: With serum LH peak day as the 'gold standard' of ovulation, we estimated accuracy and precision of ovulation day algorithms using 30 ovulatory menstrual cycles with daily urinary and serum hormones and transvaginal ultrasound. Sensitivity and specificity for estimating the presence of ovulation were tested using visually assessed ovulatory (30) and anovulatory (22) cycles. RESULTS: Sensitivity and specificity ranged from 70 to 100% for estimating presence of ovulation with twice-per-cycle, weekly, twice weekly, every-other-day and daily specimens. A combined hierarchical method estimated ovulation day using daily specimens within +/-2 days of the gold standard in 93% of cases. Accuracy of estimating ovulation day within +/-2 days using intermittent sampling ranged from 40% (weekly sampling) to 97% (every-other-day). CONCLUSIONS: A combined hierarchical algorithm using precise and accurate markers allows maximal use of available data for efficient and objective identification of ovulation using daily specimens. In intermittent sampling designs, the presence and the timing of ovulation can be estimated with good sensitivity, specificity and accuracy.

Adult↗
PubMed2000

Bacteria in the transfer catheter tip influence the live-birth rate after in vitro fertilization.

OBJECTIVE: To assess the impact of individual bacteria isolated from the vagina and tip of the embryo transfer catheter on live-birth rates. DESIGN: Prospective clinical study. SETTING: Infertility outpatient clinic of a university hospital. PATIENT(S): Ninety-one women undergoing IVF-ET. INTERVENTION(S): Cultures were obtained from the vagina for aerobic and anaerobic bacteria at the time of both sonographic egg retrieval and embryo transfer and from the tip of the embryo transfer catheter. Doxycycline treatment was started after egg retrieval. MAIN OUTCOME MEASURE(S): The live birth of one or more neonates. RESULT(S): Doxycycline had no substantial impact on the recovery of individual vaginal bacteria or on bacterial vaginosis. An increase in live-birth rate was associated with the recovery of hydrogen peroxide-producing Lactobacillus from the vagina (P=0.01) and from the embryo transfer catheter (P=0.01). In contrast, a reduction in live-birth rate was associated with recovery of Streptococcus viridans (S. viridans) from the embryo transfer catheter tip (P=0.04). CONCLUSION(S): In the setting of IVF-ET, prophylactic doxycycline had little effect on vaginal bacteria. Specific bacteria recovered from the embryo transfer catheter appear associated with a detrimental or beneficial effect or with no effect on live-birth rates.

Adult↗
PubMed2000

Ovarian follicular concentrations of activin, follistatin, inhibin, insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein-2 (IGFBP-2), IGFBP-3, and vascular endothelial growth factor in spontaneous menstrual cycles of normal women of advanced reproductive age.

Previous studies indicate that the menstrual cycles of older reproductive age women are characterized by a selective elevation of FSH associated with early development and ovulation of a dominant follicle. Several intraovarian hormones and growth factors have been identified that appear to serve important paracrine roles. The purpose of this study was to examine follicular fluid (FF) hormones and growth factors in the dominant follicle of unstimulated cycles of older, ovulatory women. We aspirated FF from the preovulatory dominant follicle in natural menstrual cycles of older subjects (age, 40-45 yr; n = 20) and younger controls (age, 20-25 yr; n = 19). FF was analyzed for estradiol, progesterone, testosterone, androstenedione, inhibin A and B, total activin A, total follistatin, insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein-2 (IGFBP-2), IGFBP-3, and vascular endothelial growth factor (VEGF) concentrations. We found that the dominant follicles from older women contain normal concentrations of steroids, inhibin A and B, IGF-II, IGFBP-2, and IGFBP-3; increased concentrations of follistatin, activin A, and VEGF; and decreased concentrations of IGF-I. Therefore, under the influence of elevated FSH, the dominant follicle in older women is highly competent in terms of hormone and growth factor secretion. We postulate that elevated FF activin may be related to the early ovulation observed in older women, whereas elevated VEGF may be related to the meiotic spindle abnormalities observed in the oocytes of older reproductive age women.

Activins↗
PubMed1999

The pattern of infertility diagnoses in women of advanced reproductive age.

OBJECTIVE: Our intention was to determine whether there is a unique pattern of infertility diagnoses in older infertile couples. STUDY DESIGN: The design of this study was a retrospective chart review study. It was performed in a tertiary referral reproductive medicine unit. There were 2 groups of patients-couples: group 1, female partner aged 20-29 (n = 105) at presentation; group 2, female partner aged 40-45 (n = 112) at presentation. All women underwent infertility evaluations between 1989 and 1994. There were no interventions. The prevalence of standard infertility diagnoses was the main outcome measure. RESULTS: The prevalence of 8 major infertility diagnoses in the younger and older groups (each couple could have >/=1 diagnosis) was as follows: (1) ovulatory factor-younger group, 56%; older group, 30%; (2) tubal factor-younger group, 34%; older group, 29%; (3) endometriosis-younger group, 13%; older group, 17%; (4) uterine factor-younger group, 1%; older group, 5%; (5) cervical factor-younger group, 4%; older group, 1%; (6) luteal deficiency-younger group, 4%; older group, 10%; (7) male factor-younger group, 32%; older group, 45%; (8) unexplained-younger group, 5%; older group, 10%. The only significant difference was an increase in ovulatory factor in the younger group. CONCLUSIONS: There is no unique pattern of infertility diagnoses in women of advanced reproductive age as seen at a tertiary referral center. We speculate that a high false-positive rate associated with standard infertility tests and a different referral pattern for older couples obscures any real differences in the etiology of infertility in older couples.

Adult↗
PubMed1999

Morphometric analysis of primordial follicle number in pigtailed monkey ovaries: symmetry and relationship with age.

We previously described a modern, three-dimensional counting method for determining primordial follicle (PF) numbers in primate ovaries using a combination of fractionator and physical dissector techniques. The purposes of our current study were 1) to apply our method to describe intraindividual differences in PF numbers between ovaries and 2) perform a linear regression analysis of age versus mean PF number per ovary. Ovaries from 16 pigtailed monkeys (Macaca nemestrina) age 0.85-12.5 yr were examined. Both ovaries were available from 11 subjects. The difference between ovaries ranged from 2% to 22% (mean +/- SD, 10 +/- 7%) and was not statistically significant. Regression analysis of data from all 16 subjects displayed a log-linear relationship according to the equation log N(a) = 4.8542 - 0.0714(age) where N(a) is the number of PF at a given chronological age. The fit for this model was highly significant (r(2) = 0.73, p </= 0.0001). Extrapolation of the model suggests that there are 71 483 PF in each ovary at the time of birth. We conclude that right and left ovaries differ little and that PF numbers follow a log-linear rate of decline during the reproductive years in this species.

Aging↗
PubMed1998

Inhibin and reproductive aging in women.

The monotropic FSH rise is the sentinel endocrine event that first indicates a woman is approaching the end of her reproductive potential. While a deficiency in inhibin has long been postulated as the immediate cause of the monotropic FSH rise, this has only recently been demonstrated to actually occur. It is our current hypothesis that when the number of preantral follicles in both ovaries drop below a threshold, then there is a subtle decrease in inhibin B which leads to the monotropic FSH rise which, in turn, accelerates follicular depletion and the attainment of the menopause.

Aging↗
PubMed1998

Endocrine changes of the perimenopause.

Reproductive aging in women is closely tied to the loss of ovarian follicles through atresia. The sentinel endocrinologic finding is the monotropic FSH rise, associated with a decline in ovarian inhibin B secretion. Fertility becomes significantly compromised long before overt clinical signs occur, such as cycle irregularity. Compromised fertility is primarily related to oocyte dysfunction. As women with regular cycles near the end of the reproductive years, the following changes are usually manifested: 1) the selection and development of a dominant follicle occurs earlier; 2) there is earlier ovulation; 3) there is a short follicular phase and total cycle length; and 4) ovarian steroid secretion is normal. The relationships, if any, between the monotropic FSH rise, accelerated follicular atresia, shortened follicular phase, and oocyte quality remain to be determined. The next phase of reproductive aging is the perimenopause. Lack of predictability is the rule with regard to the nature and duration of the perimenopause. Long cycles are interspersed with short ones, and intermittent ovulatory cycles are intermingled with periods that are hormonally indistinct from the postmenopausal state. Even after the last menstrual period, evidence of intermittent ovarian estradiol production may still be detected. Although fertility is severely compromised during the perimenopause, ovulation may occur without warning and contraception must be practiced if pregnancy is not desired. Further studies are needed to elucidate the factors contributing to oocyte abnormalities in women of advanced reproductive age, as well as the factors that determine the rate of follicle atresia and the length of the reproductive life span.

Aging↗
PubMed1998

Late-onset hematometra and hematosalpinx in a woman with a noncommunicating uterine horn. A case report.

BACKGROUND: Noncommunicating uterine horns are rare, occasionally presenting with functional endometrial cavities. Surgical removal of the noncommunicating horn is commonly performed to prevent endometriosis in these patients. CASE: A 41-year-old woman with a unicornuate uterus and noncommunicating uterine horn presented with a three-month history of right-sided pelvic pain. She had previously undergone multiple assisted reproductive technique attempts with superovulation and supraphysiologic serum estradiol levels and no apparent symptomatology or evidence of hematosalpinx during laparoscopy. Shortly after completing a donor oocyte recipient cycle, she developed acute right-sided pelvic pain. Diagnostic laparoscopy and subsequent laparotomy confirmed a right hematosalpinx and hematometra of the noncommunicating horn, with stage III endometriosis. CONCLUSION: Consideration of prophylactic resection of a noncommunicating uterine horn with a cavity should be considered in an asymptomatic, reproductive-age patient with this rare müllerian anomaly.

Adult↗
PubMed1997

Congenital cervical atresia: report of seven cases and review of the literature.

OBJECTIVE: Our aim was to evaluate the clinical course and management of congenital cervical atresia. STUDY DESIGN: This retrospective analysis included 7 patients referred to our clinic and a review of the medical literature. RESULTS: Including this case series, 58 cases of congenital cervical atresia have been reported in the literature. Forty-eight percent of patients had isolated congenital cervical atresia with a normal vagina whereas the remainder had either complete or partial vaginal atresia ("shortened blind vaginal pouches"). Surgical management has included abdominal hysterectomy or uterovaginal cannulation with or without vaginoplasty. In 59% of patients who underwent uterovaginal canalization procedures (23/39), normal menstrual bleeding was achieved. Four of these patients subsequently became pregnant and were delivered at term. CONCLUSION: Surgical canalization in selected patients with congenital cervical atresia can be successfully performed to provide patients an opportunity for conservative management, resulting in normal menstrual bleeding, resolution of cyclic pelvic pain, and some potential (albeit limited) for fertility.

Abnormalities, Multiple↗
PubMed1997

Failure of oocyte activation after intracytoplasmic sperm injection using round-headed sperm.

OBJECTIVE: To examine the outcome of intracytoplasmic sperm injection (ICSI) with round-headed sperm (globozoospermia). DESIGN: Retrospective analysis. SETTING: In vitro fertilization laboratory with extensive ICSI experience. PATIENT(S): A patient couple with infertility because of globozoospermia seeking ICSI treatment. MAIN OUTCOME MEASURE(S): Fertilization, cleavage, and pregnancy rates. INTERVENTION(S): Intracytoplasmic sperm injection and calcium ionophore. RESULT(S): This couple experienced only 7% fertilization after ICSI in their first cycle. Treatment of the unfertilized oocytes with calcium ionophore 20 hours after ICSI-induced fertilization and cleavage of 70% of the oocytes. Embryo quality was fair to good. On the second cycle, 8 of the injected oocytes were treated with ionophore immediately after ICSI and the remaining 20 oocytes were untreated. Normal fertilization was achieved in 75% of the treated and 10% of the untreated oocytes. Treatment of these unfertilized oocytes with ionophore 20 hours after ICSI resulted in fertilization in 73%. Pregnancy was not achieved after either ICSI cycle. Ultrastructural analysis indicated multiple structural abnormalities in the sperm. CONCLUSION(S): These results indicate that the round-headed sperm from this patient were incapable of oocyte activation after ICSI. This may be the reason for the frequent ICSI fertilization failure seen with this condition. Current ICSI procedures may not always overcome the infertility associated with globozoospermia, and further study of the etiology of this condition is needed.

Adult↗
PubMed1997

Utility of follicle stimulating hormone (FSH), luteinizing hormone (LH), oestradiol and FSH:LH ratio in predicting reproductive age in normal women.

The relative efficacy of follicle stimulating hormone (FSH), luteinizing hormone (LH), FSH:LH ratio and oestradiol is evaluated as a predictor of ovarian reserve (reproductive age) in normal women. Serum levels of FSH, LH, oestradiol and FSH:LH ratios were measured during menstrual cycle days 1-4 in younger (20-25 years; n = 23) and older (40-45 years; n = 32) reproductive age women with regular menstruation and normal reproductive function. On days 1-4, mean levels of FSH, oestradiol and FSH:LH ratios were significantly higher in older compared with younger women. FSH increased in concentration across cycle days in both age groups. A significantly lower LH value in younger versus older women was found only on day 1. Oestradiol showed no change across days in the younger group, but increased significantly from day 1 to day 4 in the older group. FSH values on days 1 or 2 were the best single predictor of age differences. However, the best prediction of age differences was obtained by using the combination of FSH and LH (as opposed to the FSH:LH ratio) on day 1 of the menstrual cycle.

Adult↗
PubMed1997

An accurate, simple method for unbiased determination of primordial follicle number in the primate ovary.

Previous investigations of primordial follicle (PF) number in primate ovaries have used biased, model-based techniques that require correction factors based on assumptions regarding cell size, orientation, and shape. We sought to apply several techniques from the "new stereology" to obtain unbiased number estimates. This method involves a hierarchy of systematic random sampling combined with the physical disector and fractionator techniques. The method readily allows the estimation of the coefficient of error (CE) of each sampling level as it contributes to the observed variance of the overall number estimate. We examined one ovary from each of five pigtailed monkeys (Macaca nemestrina). The mean number of PF was 15,735 +/- 6214 (mean +/- SD). The mean CE for the individual number estimates was 0.085, contributing minimally to the inter-individual coefficient of variation (CV) of the primordial follicle numbers (CV = 0.395). The correlation between age and PF number was not significant (r = -0.74, p > 0.1). The total time taken to count the 100-200 PF necessary per ovary was 4-5 h. We conclude that this method produces reliable, unbiased estimates with measurable and acceptable accuracy in a robust, efficient manner.

Aging↗
PubMed1996

Circulating levels of growth hormone, insulin-like growth factor-I and growth hormone binding protein in normal women of advanced reproductive age.

OBJECTIVE: Women experience an age-related decline in fertility despite regular ovulatory cycles and normal production of ovarian steroids. Growth hormone and IGF-I are both reported to decline with age, and there is evidence that both hormones promote intraovarian actions of gonadotrophins. The purpose of this study was to characterize circulating levels of GH and IGF-I in normal, older reproductive age women with ovulatory cycles. DESIGN: Prospective, controlled. PATIENTS: Twenty-eight regularly cycling older (n = 16) and younger (n = 12) women were recruited for daily blood sampling throughout a menstrual cycle. MEASUREMENTS: Serum obtained from daily blood sampling was analysed for LH, FSH, oestradiol (E2) and progesterone (P). Serum obtained from frequent sampling during the admission was analysed for pulsatile GH secretion. IGF-I and GH binding protein (GHBP) were also measured in subsets of the two age groups. RESULTS: All subjects exhibited normal patterns of LH, FSH, E2 and P consistent with ovulatory cycles. There were no differences between the two age groups in integrated 24-hour GH secretion or in GH pulse amplitude or frequency. There were no differences in GH secretion between the early follicular and miduluteal phases when data were combined for the two subject groups. Plasma concentrations of IGF-I were significantly lower throughout the cycle in the older women. There were no significant differences in levels of GHBP across the cycle or between the two age groups. CONCLUSIONS: IGF-I decreases with age in women without identifiable changes in the amount or pattern of GH secretion or in circulating GHBP concentrations. Decreased IGF-I production may be related to decreased ovarian gonadotrophin sensitivity in older reproductive age women.

Adult↗
PubMed1996

Changes in centrosomal domains during meiotic maturation in the human oocyte.

The distribution of microtubule organizing centres (MTOC) in the human oocyte was examined using the microtubule-active drug, taxol, to promote polymerization. Oocytes were obtained from gonadotrophin-stimulated in-vitro fertilization (IVF) patients and examined during various phases of meiotic maturation using confocal fluorescence microscopy. During the prophase of meiosis I, taxol failed to stimulate microtubule nucleation in any region of the cells. Only a few microtubules were visible in the oocyte cortex. As the transition from prophase to metaphase began, during germinal vesicle breakdown, taxol stimulated the appearance of a small number of isolated aster-like arrays of microtubules in the cortex, predominantly in regions adjacent to the nucleus. Oocytes treated with taxol when they had reached the first meiotic metaphase exhibited a large number of aster-like microtubule arrays. These structures were predominantly located in the cortical region of the oocyte, but smaller arrays were also visible in the endoplasmic areas. There did not appear to be any increased density of asters in any particular cortical or endoplasmic region. Oocytes treated with taxol during the second metaphase of meiosis exhibited a similar response to the drug as seen during metaphase I, Again, the microtubule asters were most prevalent in the cortex, with smaller, less dense arrays in the endoplasm. The metaphase spindle was also affected by taxol as revealed by increased density and hyperelongation of microtubules at the poles of the spindle as compared to untreated oocytes. The metaphase plate of chromosomes was highly disrupted by taxol treatment, most likely due to the forces generated by microtubule elongation. We conclude that the human oocyte develops MTOC as meiotic maturation proceeds beyond the prophase I arrest. The first MTOCs are perinuclear, but the number and distribution increases widely as the oocytes enter metaphase. We hypothesize that the centrosome of the human recruits several MTOC domains for the assembly of the meiotic spindles in both meiotic divisions. It is speculated that one or more of the non-spindle-associated MTOCs may combine with sperm centrosomal material during fertilization to create the complete centrosome needed for embryonic mitosis. The widespread distribution of MTOC foci throughout the cortex may ensure this recombination regardless of the point of sperm incorporation into the oocyte.

Adult↗
PubMed1996

Influence of maternal age on meiotic spindle assembly in oocytes from naturally cycling women.

To examine the effects of maternal ageing on the meiotic apparatus, we obtained oocytes from naturally cycling women in two age groups, including younger (aged 20-25 years) and older (aged 40-45 years) women. Using high-resolution confocal microscopy we obtained a detailed picture of the meiotic spindle and chromosome placement during various phases of meiosis. Our data revealed that the meiotic spindle in older women is frequently abnormal, both with regard to chromosome alignment and the microtubule matrix that comprise the meiotic spindle. The spindle in 79% of the oocytes from the older group exhibited abnormal tubulin placement and one or more chromosomes were displaced from the metaphase plate during the second meiotic division. In contrast, only 17% of the oocytes from the younger age group exhibited aneuploid conditions. The majority of eggs from this group possessed a well ordered, meiotic spindle containing chromosomes that were fully aligned within a distinct metaphase plate in the spindle. Chromosome management during meiosis is directed by microtubule assembly within the spindle. These data suggest that the regulatory mechanisms responsible for assembly of the meiotic spindle are significantly altered in older women, leading to the high prevalence of aneuploidy.

Adult↗
PubMed1996

Reproductive aging: accelerated ovarian follicular development associated with a monotropic follicle-stimulating hormone rise in normal older women.

Women experience a decline in fertility that precedes the menopause by several years. Previous studies have demonstrated a monotropic rise in FSH associated with reproductive aging: however, the mechanism of this rise and its role in the aging process are poorly understood. The purpose of this study was to characterize ovarian follicular development and ovarian hormone secretion in older reproductive age women. Sixteen women, aged 40-45 yr, with regular ovulatory cycles were studied. The control group consisted of 12 ovulatory women, aged 20-25 yr. Serum obtained by daily blood sampling was analyzed for FSH, LH, estradiol (E), progesterone, and inhibin (Monash polyclonal assay). Follicle growth and ovulation were documented by transvaginal ultrasound. Older women had significantly higher levels of FSH throughout the menstrual cycle. E, progesterone, LH, and inhibin levels did not differ between the two age groups when compared relative to the day of the LH surge. Ultrasound revealed normal growth, size, and collapse of a dominant follicle in all subjects. Older women had significantly shorter follicular phase length associated with an early acute rise in follicular phase E, reflecting accelerated development of a dominant follicle. We conclude that older reproductive age women have accelerated development of a dominant follicle in the presence of the monotropic FSH rise. This is manifested as a shortened follicular phase and elevated follicular phase E. The fact that ovarian steroid and inhibin secretion were similar to those in the younger women suggests that elevated FSH in women of advanced reproductive age may represent a primary neuroendocrine change associated with reproductive aging.

Adult↗
PubMed1996

Ovarian follicular development and the follicular fluid hormones and growth factors in normal women of advanced reproductive age.

Reproductive aging in women (a physiological decline in the function of the hypothalamic-pituitary-ovarian axis) is an infrequently investigated and poorly understood biological phenomenon. Although menstrual irregularity and anovulation are known to precede the menopause, normal women in their fifth decade experience a profound decrease in fertility while still experiencing regular menstrual cycles. To further our understanding of the physiological changes associated with reproductive aging, this study examined the spontaneous development and function of ovarian follicles in normal women, aged 40-45 yr. The subjects were women (n = 21), aged 40-45 yr, who had regular 25- to 35-day ovulatory menstrual cycles, were not infertile, had no medical problems, and met specific criteria for weight, diet, and exercise. The controls were normal women (n = 20), age 20-25 yr, who met the same criteria. The subjects were monitored with daily hormone measurements [LH, FSH, estradiol (E), progesterone (P), and inhibin] and pelvic sonograms from day 1 of their study cycle until the dominant ovarian follicle reached a mean diameter of 15 mm and/or a serum E level of 550 pmol/L or higher was attained. At that time, 10,000 U hCG were given, and a transvaginal sonographic follicle aspiration was performed 32 h later. The follicular fluid (FF) was collected, stored frozen at -70 C, and later analyzed for E, P, testosterone (T), androstenedione, inhibin, insulin-like growth factor I (IGF-I), and IGF-II. The number of cycle days to aspiration was lower (11.6 vs. 15.6 days; P < 0.001) and the early follicular phase mean FSH and mean E levels were higher (9.3 vs. 6.6 mIU/mL and 305 vs. 160 pmol/L; P < 0.01) in the older (O) group compared to the younger group. There was a strong trend toward higher FF mean E (2280 vs. 1931 nmol/L) and lower FF mean T (978 vs. 2361 pmol/L) levels in group O. The E/T ratio was significantly higher (5253 vs. 2408; P < 0.03) in group O. In group O, the mean FF P levels were increased as well (25.1 vs. 18.8 micromol/L; P < 0.01). The serum mean IGF-I (153 vs. 226 ng/mL; P < 0.001) and FF mean IGF-I (113 vs. 158 ng/mL; P < 0.02) levels were significantly decreased in group O. There were no differences between groups in serum or FF IGF-II or inhibin levels. Whether reproductive aging is an intrinsic ovarian process or the ovary is simply responding to exogenous influences, the ovary in general and its follicles in particular are the primary site of the effects of aging. Ovarian follicles in older ovulatory women have some unique features: 1) the follicles are the same size as those in younger women, but form more rapidly; 2) secretion of E and inhibin is not compromised; 3) the concentrations of steroids in the FF are indicative of a healthier follicle, i.e. increased P levels and higher estrogen to androgen ratio; and 4) serum and FF levels of IGF-I are decreased, but there are no differences in IGF-II levels.

Adult↗