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Biomedical subjects

N Laufer

Publications and source records attributed to N Laufer.

At least 145 records · Page 8Linked to original sources
PubMed1986

Prevention of subsequent exercise-induced periinfarct ischemia by emergency coronary angioplasty in acute myocardial infarction: comparison with intracoronary streptokinase.

To compare the efficacy of emergency percutaneous transluminal coronary angioplasty and intracoronary streptokinase in preventing exercise-induced periinfarct ischemia, 28 patients presenting within 12 hours of the onset of symptoms of acute myocardial infarction were prospectively randomized. Of these, 14 patients were treated with emergency angioplasty and 14 patients received intracoronary streptokinase. Recatheterization and submaximal exercise thallium-201 single photon emission computed tomography were performed before hospital discharge. Periinfarct ischemia was defined as a reversible thallium defect adjacent to a fixed defect assessed qualitatively. Successful reperfusion was achieved in 86% of patients treated with emergency angioplasty and 86% of patients treated with intracoronary streptokinase (p = NS). Residual stenosis of the infarct-related coronary artery shown at predischarge angiography was 43.8 +/- 31.4% for the angioplasty group and 75.0 +/- 15.6% for the streptokinase group (p less than 0.05). Of the angioplasty group, 9% developed exercise-induced periinfarct ischemia compared with 60% of the streptokinase group (p less than 0.05). Thus, patients with acute myocardial infarction treated with emergency angioplasty had significantly less severe residual coronary stenosis and exercise-induced periinfarct ischemia than did those treated with intracoronary streptokinase. These results suggest further application of coronary angioplasty in the management of acute myocardial infarction.

Adult↗
PubMed1986

Semen evaluation following preparation for in vitro fertilization of human oocytes.

Semen preparation is an important step of in vitro fertilization (IVF) and can affect the success of this procedure. Prior to oocyte insemination, spermatozoa are washed to remove seminal plasma which is believed to contain decapacitation factors. This study was undertaken to evaluate the effect of preparation on semen quality and subsequent successful IVF. Oocytes were recovered from 12 hMG/hCG-stimulated women by laparoscopy, and 6 h later semen specimens were obtained from the male partners. After liquefaction, 1 ml of semen was centrifuged twice in Ham's F10 medium supplemented with 10% of homologous serum, and the final suspension was used to inseminate the preovulatory eggs. In the initial and washed-sperm suspensions, motility was evaluated by the MEP method, and the occurrence of acrosome reaction and sperm viability were evaluated by the triple-stain technique. Fertilization was documented by the formation of two pronuclei. Washing caused a significant decrease in the percentage of motile sperm from 68% to 59% but significantly increased mean sperm velocity from 26 to 29 micron/sec (p less than 0.01). The mean fertilization rate was 65%, and no correlation was found with any of the parameters of semen quality before or after washing. Semen preparation for IVF is associated with a decrease in the percentage of motile sperm that does not seem to affect the fertilizing ability of normal spermatozoa but may be of importance in patients with abnormal semen.

Cell Survival↗
PubMed1986

Advanced secretory changes in the proliferative human endometrial epithelium following clomiphene citrate treatment.

In an effort to characterize the effect of clomiphene citrate (CC) on the human endometrium, we took biopsy specimens of the endometrium 24 to 48 hours after CC treatment (100 to 250 mg/day for 5 consecutive days). Nineteen biopsy specimens were taken from 19 patients. Fifteen of the patients suffered from anovulatory infertility associated with oligomenorrhea or normal cycle length. The other four patients were amenorrheic, two in association with hypogonadotropic hypogonadism and two with hypergonadotropic hypogonadism. The histopathology of all samples was evaluated with the use of light microscopy, including periodic acid-Schiff (PAS) and PAS-diastase staining for glycogen demonstration. All samples were also examined with the use of scanning electron microscopy (SEM). Serum levels of estradiol (E2), progesterone (P), luteinizing hormone, and follicle-stimulating hormone were determined on the day of biopsy. In 10 of the 19 biopsy specimens, local or diffuse signs of early secretory events were demonstrated by the presence of subnuclear vacuolization and glycogen in the glandular epithelial cells. SEM corroborated these findings of advanced secretory changes by demonstrating apical protrusions at luminal epithelial cells and secretory products within the glands' openings. The E2 levels ranged between 110 and 1500 pg/ml (mean, 371 pg/ml) and P levels were either undetectable or less than 1.1 ng/ml. The two patients with hypogonadotropic hypogonadism both exhibited the same phenomena; those with primary ovarian failure had atrophic endometrium even after high-dose CC treatment. This observation, together with the low P levels detected, indicating the lack of luteinization, suggests a possible direct effect of CC on the endometrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Anovulation↗
PubMed1985

Follicular development: lessons learned from human in vitro fertilization.

In vitro fertilization has offered new insights into our understanding of ovulation induction, folliculogenesis, and luteal phase events. This new information is provided by the ability to precisely study these cycles in a frequent and sequential fashion through the use of peripheral blood markers, ultrasound evaluation, and follicular fluid constituents and cell culture techniques, as well as direct observation of the oocyte, fertilization, and cleavage. In these stimulated cycles the follicular phase serum estradiol levels in conjunction with ultrasound were evaluated; a poor correlation was shown between follicle size and number and estrogen production. This distinct dyssynchrony suggests the recruitment of a number of cohorts of follicles in each stimulated cycle. From the biochemical markers in follicular fluid, cyclic adenosine monophosphate has a distinct predictive value in regard to pregnancy in in vitro fertilization-embryo transfer cycles. In the luteal phase, the mass effect of aspiration of great numbers of granulosa cells, the effect of supplemental progesterone, and the influence of high follicular phase estradiol levels remain controversial and, therefore, a less clear cut pattern emerges. Variations in the protocol have not greatly improved the major problems of folliculogenesis associated with ovulation induction and an in vitro fertilization-embryo transfer program, that is, follicular asynchrony and luteal phase deficiency.

Body Fluids↗
PubMed1985

The day of initiation of human menopausal gonadotropin stimulation affects follicular growth in in vitro fertilization cycles.

The attainment of synchronous follicular development in human menopausal gonadotropin/human chorionic gonadotropin-stimulated cycles for in vitro fertilization (IVF) continues to be a perplexing problem. Two regimens of follicle stimulation for IVF cycles were, therefore, compared. Twenty-nine patients commenced human menopausal gonadotropin (hMG) therapy on day 1 of the menstrual cycle (Group I), while 30 women received hMG from the third day of the cycle (Group II). The hMG therapy was tailored to the individual patients's response, based on ultrasonographic measurements of follicular size and serum estradiol (E2) levels. Both groups of patients received a mean of 19.6 +/- 1.4 ampules of hMG over a mean of 6.1 +/- 0.2 days. The pattern of serum E2 and progesterone levels in the periovulatory and luteal phase was not affected by the day of initiation of hMG therapy, although Group I patients demonstrated lower (P less than 0.05) E2 levels on the 2 days prior to human chorionic gonadotropin (hCG) administration. In terms of follicle growth, Group II follicles consistently demonstrated a significantly (P less than 0.01, chi 2 test) larger proportion of medium- and large-sized follicles compared to Group I follicles on almost all of the days when ultrasonographic measurements were taken. In addition, Group II follicles demonstrated an earlier shift (day-1) to the larger follicles than Group I follicles (day 0). Significantly (P less than 0.001) more oocytes were recovered per aspirated follicle in Group II patients, but the fertilization rate per oocyte was greater (P less than 0.003) for Group I oocytes. Nevertheless, pregnancy rates did not differ between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Estradiol↗
PubMed1985

Steroid secretion by human oocyte--corona--cumulus complexes associated with conceptions following in vitro fertilization.

Seventy-one oocyte--corona--cumulus complexes (OCCCs) were obtained from eight women who conceived and delivered following in vitro fertilization (IVF) and eight women who were matched for the number of embryos transferred into the uterus but failed to conceive following the procedure. The steroid secretion of these OCCCs was assessed during a 24-hr culture period. Intermediate (N = 35) and mature (N = 36) complexes did not differ in steroid secretion, and progesterone was the major steroid secreted. OCCCs associated with a fertilized oocyte (N = 59) produced significantly (P less than 0.02) higher levels of progesterone than those associated with nonfertilized oocytes (N = 12) (515 +/- 53 vs 231 +/- 70 ng/OCCC/24 hr) but comparable levels of estradiol (9.17 +/- 1.14 vs 6.55 +/- 2.0 ng/OCCC/24 hr) and testosterone (0.34 +/- 0.09 vs 0.22 +/- 0.05 ng/OCCC/24 hr). Steroid production by OCCCs of oocytes which continued to cleave was not different from that of oocytes which did not cleave following fertilization, but the estradiol-to-testosterone ratio was significantly higher (31.4 +/- 3.5 vs 19.1 +/- 3.3; P less than 0.02) in the former group. The degree of cleavage was not related to the levels of steroid secretion. Cleaved oocytes associated with viable pregnancies (N = 28) were derived from OCCCs which secreted significantly less testosterone than those which did not result in a pregnancy following transfer (N = 26) (0.27 +/- 0.04 vs 0.41 +/- 0.04 ng/OCCC/24 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Embryo Transfer↗
PubMed1985

Altered follicular development in clomiphene citrate versus human menopausal gonadotropin-stimulated cycles for in vitro fertilization.

The pattern of periovulatory and luteal phase serum estradiol (E2) and progesterone (P) as well as follicular fluid (FF) E2, P, androgen, gonadotropin, and prolactin concentrations of eight women undergoing clomiphene citrate (CC)/human chorionic gonadotropin (hCG) stimulation and eight women undergoing human menopausal gonadotropin (hMG)/hCG stimulation of follicular development for the purpose of in vitro fertilization were compared. Ovulation was induced with either a 5-day course of CC (100 mg/day beginning on day 5 of the cycle) or an individualized hMG regimen, and laparoscopy was performed 36 hours after hCG administration. The length of the luteal phase was significantly longer (P less than 0.05) in the CC-treated group as compared with the hMG-treated group. The pattern of serum E2 levels differed significantly (P less than 0.01) in that E2 levels were lower in the early and midluteal phase in CC-stimulated cycles; in addition, a delayed second E2 peak was observed in the late luteal phase in these women. Serum P levels, however, were lower in the hMG-stimulated group. Analysis of FF hormone concentrations revealed significantly (P less than 0.05) higher concentrations of E2 and androsterone in the FF of hMG-treated patients. It is concluded that follicular development in CC-stimulated cycles differs markedly from that in hMG-stimulated cycles. These differences may reflect either an altered follicular maturational process or may represent a direct inhibitory effect of CC on follicular steroidogenesis.

Adult↗
PubMed1985

A simple technique of ovarian suspension in preparation for in vitro fertilization.

Because laparoscopic ovum harvest for IVF is becoming more common, efforts must be made at the time of prior infertility surgery to render the ovaries accessible for ovum recovery. In this report, a simple technique of ovarian suspension in preparation for eventual IVF is described. Seventeen infertile patients undergoing lysis of adhesions underwent ovarian suspension by plication of the suspensory ligament of the ovary with a running suture of 3-0 Prolene, thus apposing the proximal pole of the ovary to the anterior-lateral surface of the uterus. Because the fallopian tube is independent of the sutured structures, the tubal anatomy was undisturbed. Fourteen of these 17 patients have since undergone laparoscopy during IVF. In 12 cases, despite the recurrence of adhesions, the ovaries were accessible for ovum recovery from all aspects. Two patients conceived normally after the lysis of adhesions. This simplified ovarian suspension represents an effective technique for facilitating ovum recovery for IVF which may not disturb fallopian tube ovum pickup or transport mechanisms.

Fallopian Tubes↗
PubMed1985

Renin-like activity in ovarian follicular fluid.

Angiogenesis is a feature of ovarian follicle and corpus luteum development. Ovarian homogenates and follicular fluid (FF) contain factors that stimulate new vessel formation. Because the renin-angiotensin system has been shown to facilitate angiogenesis, renin activity was measured in FF and plasma from 20 normal, ovulatory women who were undergoing in vitro fertilization and were therefore stimulated with human menopausal gonadotropin/human chorionic gonadotropin. Serum estradiol (E2) and FF E2 and progesterone (P) were also determined and correlated with FF and plasma renin activity. FF renin activity was significantly higher than plasma renin activity (55.8 +/- 7.9 versus 3.8 +/- 0.7 ng of angiotensin I/ml/hour, P less than 0.001). Positive correlations were found between FF E2 and renin activity (r = 0.53, P less than 0.05). There was also a correlation between plasma renin activity and serum E2 (r = 0.69, P less than 0.05). No correlation was present between FF P and renin activity. The high renin-like activity present in FF after stimulation with gonadotropins could be involved in the mechanism of angiogenesis and may play an important role in events related to reproductive processes.

Estradiol↗
PubMed1985

Adenosine 3',5'-monophosphate levels in human follicular fluid: relationship to oocyte maturation and achievement of pregnancy after in vitro fertilization.

cAMP, estradiol (E2), and progesterone levels were determined in 24 follicular fluid samples obtained from 8 women who conceived after in vitro fertilization and in 47 samples from 26 women who did not. Follicular development was induced by human menopausal gonadotropin, and maturation of retrieved oocytes was assessed by the degree of cumulus mucification and corona dispersal. The mean follicular fluid cAMP concentration was significantly (P less than 0.001) lower in women who became pregnant than in those who did not (106 vs. 241 pmol/ml), while the mean E2 level was significantly (P less than 0.01) higher (727 vs. 497 ng/ml), and the progesterone to E2 ratio was significantly (P less than 0.05) lower (9.5 vs. 18.0). Overall, follicles of immature, intermediate, and mature oocytes did not differ in cAMP content. However, intermediate and mature oocytes from women who became pregnant were derived from follicles containing significantly (P less than 0.01) lower cAMP levels than those of women who did not become pregnant (66 and 122 vs. 233 and 288 pmol/ml, respectively). Furthermore, fertilized oocytes leading to conception originated from follicles with significantly (P less than 0.001) lower cAMP concentrations than the follicles that yielded nonfertilized oocytes or fertilized oocytes not leading to conception (92 vs. 270 and 240 pmol/ml, respectively). Similarly, significantly (P less than 0.05) lower cAMP levels were found in the follicular fluid of cleaved oocytes resulting in a pregnancy compared to those that did not (86 vs. 236 pmol/ml). It is concluded that low levels of cAMP are associated with successful fertilization and cleavage of human oocytes in vitro resulting in viable pregnancies and may, therefore, be used as a marker of optimal follicular development in in vitro fertilization cycles.

Adult↗
PubMed1985

Effect of caffeine on human sperm penetration into zona-free hamster ova.

The effect of caffeine on spermatozoal ability to penetrate zona-free hamster ova was examined on fresh and frozen-thawed semen samples. The mean motility of 10 fresh semen samples incubated with caffeine significantly increased from 29% to 35%. Sperm penetration into zona-free hamster ova did not differ between the control group and the specimens to which caffeine was added. The same effect of caffeine on sperm motility and hamster ova penetration was noted in the frozen-thawed sperm samples. Motility was enhanced by 21%, but hamster ova penetration did not significantly change. The increase in sperm motility caused by caffeine does not change the fertilizing ability of fresh and frozen-thawed human sperm.

Animals↗
PubMed1985

Reduced penetration of zona-free hamster ova by cryopreserved human spermatozoa.

The effect of cryopreservation on human sperm fertilizing potential was assessed by using the human sperm penetration into zona-free hamster ovum test. Semen samples from 12 fertile men were compared before and after cryopreservation for motility, sperm penetration rate, and number of sperm cells incorporated per oocyte. In fresh samples sperm concentration was 102 +/- 51 X 10(6) cells/ml, motility 66 +/- 14%, penetration rate 77.8 +/- 19%, and sperm incorporation 4.3 +/- 3.9 sperm per ovum. Frozen-thawed sperm cells showed a marked reduction of 61 +/- 21% (p less than 0.001) in motility. Penetration rate was reduced by 53 +/- 34% (p less than 0.01), and sperm incorporation dropped by 50 +/- 28% (p less than 0.05). Despite this substantial reduction in all three parameters, 75% of the samples maintained a penetration rate exceeding 14%, which is the lower limit for fertile semen. For the individual subject the decrease in sperm motility did not reflect actual fertility potential as expressed by its ability to penetrate zona-free hamster ova. These findings are related to morphological and biochemical changes in frozen-thawed semen and apparently are correlated with the decrease in pregnancy rates after cryopreservation. This test may be a valuable supplement to routine microscopic semen analysis for semen cryopreservation candidates.

Animals↗
PubMed1984

Assessment of potentially salvageable myocardium during acute myocardial infarction: use of postextrasystolic potentiation.

Twenty-three patients with evolving acute myocardial infarction (AMI) undergoing catheterization for thrombolytic therapy had interventional contrast ventriculography using programmed atrial stimulation. Postextrasystolic (PES) potentiation was present in 67% of infarct-related segments up to 9 hours after the onset of AMI. The presence of segmental potentiation was not related to time from onset of pain to ventriculography, initial ejection fraction, presence of collaterals, left ventricular end-diastolic pressure or the PES delay. In 18 patients reperfusion was successful using intracoronary streptokinase an average of 6.2 hours after the onset of AMI; in these patients repeat contrast ventriculography was performed an average of 11 days after AMI. Improved chronic segmental ventricular function was predicted by the presence of collaterals to the infarct-related artery at the time of acute catheterization (p = 0.02), but was best predicted by analysis of acute PES potentiation (p less than 0.0001). The predictive value of PES analysis was highest in segments without collaterals. Thus, atrial stimulation is safe during AMI and analysis of segmental ventricular function shows potentially viable myocardium up to 9 hours after the onset of AMI. In addition, analysis of PES segmental function can predict chronic function if reperfusion is successful, especially in segments without collaterals. PES ventriculographic analysis may allow prospective determination of which patients during AMI are most likely to benefit from acute thrombolytic therapy.

Aged↗
PubMed1984

Human in vitro fertilization employing individualized ovulation induction by human menopausal gonadotropins.

One hundred six women suffering from obstructive tubal disease not corrected by previous surgery were treated in an in vitro fertilization (IVF) program. Ovulation was induced by 3 amps of human menopausal gonadotropin (HMG)/day starting on the third day of the cycle for 5 days. In most of the patients the regimen was continued for another 1-3 days, depending on the individual's ovarian response (mean, 20 +/- 5 amps/cycle). Monitoring consisted of daily follicular ultrasonography and serum estradiol measurements. Human chorionic gonadotropin (HCG), 10,000 IU, was administered when more than two large (1.5 to 1.8 cm in diameter) follicles were visualized. Using this regimen, a mean of five follicles per woman was aspirated, from which a mean of 3.9 ova was recovered. The oocytes were pre-incubated for 8 or 24 hr, according to the morphological degree of mucification and dispersal of the oocyte-corona-cumulus complex. Following exposure to washed spermatozoa for 16 hr, a 68% fertilization rate was obtained. Oocytes were transferred into the uterus 48 hr after laparoscopy. Ninety-nine transfers (93% of the women) of 1-8 embryos (mean, 2.9/woman) were performed and resulted in 16 clinical pregnancies. No pregnancies occurred in 14 women transferred with one to three oocytes in the pronuclear stage and only one pregnancy (7.1%) was obtained in 14 women transferred with one cleaved oocyte. Over 70% of the women were transferred with two or more cleaved oocytes: in this group the pregnancy/transfer rate was 21%. Of the pregnant women 5 of 16 (31%) aborted between 6 and 10 weeks of gestation and 1 (6%) had an ectopic pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

The use of ovarian ultrasonography in monitoring ovulation induction.

Ovarian ultrasonography is a new diagnostic technique which has become almost essential in monitoring ovulation. Recent improvements in ultrasound technology have allowed for accurate assessment of the number and size of the developing follicles and their rate of growth, as well as ovulation and postovulatory events. In the nonstimulated cycle follicular size correlates well with optimal maturation and there is a linear correlation between follicular diameter and plasma estradiol (E2 levels). In stimulated cycles, because of asynchrony of various recruited cohorts of follicles, these rules are not as steadfast. These observations indicate that when there is endogenous gonadotropic activity, follicular growth stimulated by human menopausal gonadotropins (hMG) does not develop synchronously. The aim should be, therefore, not only to improve the monitoring system but mainly to synchronize the cohorts of follicles recruited for development in any one cycle by a better regimen for ovulation induction. In view of the high success rate of hMG treatment in patients without endogenous gonadotropin secretion, it is tempting to speculate that inducing similar conditions in women with endogenous gonadotropin production may have a significant change in the pattern of follicular development in their conception rate.

Clomiphene↗