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Michael P. Steinkampf

Bio: Michael P. Steinkampf is an academic researcher from University of Alabama at Birmingham. The author has contributed to research in topics: Polycystic ovary & Infertility. The author has an hindex of 17, co-authored 51 publications receiving 3363 citations.


Papers
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Journal ArticleDOI
TL;DR: Threshold values for sperm concentration, motility, and morphology can be used to classify men as subfertile, of indeterminate fertility, or fertile and none of the measures are diagnostic of infertility.
Abstract: Background Although semen analysis is routinely used to evaluate the male partner in infertile couples, sperm measurements that discriminate between fertile and infertile men are not well defined. Methods We evaluated two semen specimens from each of the male partners in 765 infertile couples and 696 fertile couples at nine sites. The female partners in the infertile couples had normal results on fertility evaluation. The sperm concentration and motility were determined at the sites; semen smears were stained at the sites and shipped to a central laboratory for an assessment of morphologic features of sperm with the use of strict criteria. We used classification-and-regression-tree analysis to estimate threshold values for subfertility and fertility with respect to the sperm concentration, motility, and morphology. We also used an analysis of receiver-operating-characteristic curves to assess the relative value of these sperm measurements in discriminating between fertile and infertile men. Results The su...

1,129 citations

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TL;DR: Clomiphene is superior to metformin in achieving live birth in infertile women with the polycystic ovary syndrome, although multiple birth is a complication.
Abstract: Background The polycystic ovary syndrome is a common cause of infertility. Clomiphene and insulin sensitizers are used alone and in combination to induce ovulation, but it is unknown whether one approach is superior. Methods We randomly assigned 626 infertile women with the polycystic ovary syndrome to receive clomiphene citrate plus placebo, extended-release metformin plus placebo, or a combination of metformin and clomiphene for up to 6 months. Medication was discontinued when pregnancy was confirmed, and subjects were followed until delivery. Results The live-birth rate was 22.5% (47 of 209 subjects) in the clomiphene group, 7.2% (15 of 208) in the metformin group, and 26.8% (56 of 209) in the combination-therapy group (P<0.001 for metformin vs. both clomiphene and combination therapy; P=0.31 for clomiphene vs. combination therapy). Among pregnancies, the rate of multiple pregnancy was 6.0% in the clomiphene group, 0% in the metformin group, and 3.1% in the combination-therapy group. The rates of first...

874 citations

Journal ArticleDOI
TL;DR: A large, randomized, controlled clinical trial of superovulation with gonadotropins and intrauterine insemination for infertility in 932 couples in which the woman had no identifiable infertility factor and the man had motile sperm finds that the 231 couples in the group treated withsuperovulation and intracervical-insemination had a higher rate of pregnancy.
Abstract: Background Induction of superovulation with gonadotropins and intrauterine insemination are frequently used to treat infertility. We conducted a large, randomized, controlled clinical trial of these treatments. Methods We studied 932 couples in which the woman had no identifiable infertility factor and the man had motile sperm. The couples were randomly assigned to receive intracervical insemination, intrauterine insemination, superovulation and intracervical insemination, or superovulation and intrauterine insemination. Treatment continued for four cycles unless pregnancy was achieved. Results The 231 couples in the group treated with superovulation and intrauterine insemination had a higher rate of pregnancy (33 percent) than the 234 couples in the intrauterine-insemination group (18 percent), the 234 couples in the group treated with superovulation and intracervical insemination (19 percent), or the 233 couples in the intracervical-insemination group (10 percent). Stratified, discrete-time Cox proporti...

467 citations

Journal ArticleDOI
TL;DR: Findings fail to support the view that extended-release metformin, alone or combined with clomiphene citrate, improves live birth rates in previously infertile women with PCOS, and clomine alone seems preferable as first-line treatment for these patients despite a risk of multiple births.
Abstract: Polycystic ovary syndrome (PCOS) may be the commonest cause of female infertility. In addition to anovulation, early pregnancy loss, and later complications of pregnancy, obesity-which is common in women with PCOS-has been implicated. Small-scale trials suggest that treatment with an insulin sensitizer such as metformin, alone or combined with clomiphene citrate, is at least equal to, and possibly superior to clomiphene alone as treatment for infertility. This randomized, placebo-controlled trial evaluated both of these agents, alone and combined, in 626 infertile women diagnosed as having PCOS. Extended-release metformin was given in a maximum dose of 1 gm daily, and clomiphene concurrently in a dose of 50 mg daily, starting on menstrual day 3. The dose of clomiphene was doubled if necessary. Treatment continued for up to six cycles over 30 weeks. Baseline variables were similar in all treatment groups. Rates of live birth were 22.5% in clomiphene-treated patients, 7.2% with metformin therapy, and 26.8% with combination therapy. The differences between the metformin group and the clomiphene and combined treatment groups were significant. Combined therapy was not significantly more effective than clomiphene alone. Similar results were obtained when adjusting for body mass index. Among secondary outcomes, ovulation rates were significantly higher with combined treatment than in either of the single-drug groups, but this did not translate into increased live births. Rates of conception and of live births per ovulatory cycle were significantly higher in the clomiphene and combined drug groups than with metformin alone. There were no multiple pregnancies in the metformin group. There were no notable group differences in rates of first-trimester pregnancy loss. Compared to metformin-treated women, those given clomiphene or combined therapy had significant increases in sex hormone-binding globulin levels and decreased free androgen indices. Serious adverse events-mostly pregnancy complications-were most frequent in the clomiphene and combined treatment groups. Gastrointestinal side effects were more frequent, and vasomotor and ovulatory symptoms less frequent, in the metformin group than in the clomiphene group. These findings fail to support the view that extended-release metformin, alone or combined with clomiphene citrate, improves live birth rates in previously infertile women with PCOS. Clomiphene alone seems preferable as first-line treatment for these patients despite a risk of multiple births. Combining the two drugs does not further increase the chances of a live birth.

252 citations


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TL;DR: Semen quality of the reference population was superior to that of the men from the general population and normozoospermic men, and provide an appropriate tool in conjunction with clinical data to evaluate a patient's semen quality and prospects for fertility.
Abstract: BACKGROUND Semen quality is taken as a surrogate measure of male fecundity in clinical andrology, male fertility, reproductive toxicology, epidemiology and pregnancy risk assessments. Reference intervals for values of semen parameters from a fertile population could provide data from which prognosis of fertility or diagnosis of infertility can be extrapolated. METHODS Semen samples from over 4500 men in 14 countries on four continents were obtained from retrospective and prospective analyses on fertile men, men of unknown fertility status and men selected as normozoospermic. Men whose partners had a time-to-pregnancy (TTP) of < or =12 months were chosen as individuals to provide reference distributions for semen parameters. Distributions were also generated for a population assumed to represent the general population. RESULTS The following one-sided lower reference limits, the fifth centiles (with 95th percent confidence intervals), were generated from men whose partners had TTP < or = 12 months: semen volume, 1.5 ml (1.4-1.7); total sperm number, 39 million per ejaculate (33-46); sperm concentration, 15 million per ml (12-16); vitality, 58% live (55-63); progressive motility, 32% (31-34); total (progressive + non-progressive) motility, 40% (38-42); morphologically normal forms, 4.0% (3.0-4.0). Semen quality of the reference population was superior to that of the men from the general population and normozoospermic men. CONCLUSIONS The data represent sound reference distributions of semen characteristics of fertile men in a number of countries. They provide an appropriate tool in conjunction with clinical data to evaluate a patient's semen quality and prospects for fertility.

2,264 citations

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TL;DR: In this article, the authors provide a guided tour through the development of artificial self-propelling microparticles and nanoparticles and their application to the study of nonequilibrium phenomena, as well as the open challenges that the field is currently facing.
Abstract: Differently from passive Brownian particles, active particles, also known as self-propelled Brownian particles or microswimmers and nanoswimmers, are capable of taking up energy from their environment and converting it into directed motion. Because of this constant flow of energy, their behavior can be explained and understood only within the framework of nonequilibrium physics. In the biological realm, many cells perform directed motion, for example, as a way to browse for nutrients or to avoid toxins. Inspired by these motile microorganisms, researchers have been developing artificial particles that feature similar swimming behaviors based on different mechanisms. These man-made micromachines and nanomachines hold a great potential as autonomous agents for health care, sustainability, and security applications. With a focus on the basic physical features of the interactions of self-propelled Brownian particles with a crowded and complex environment, this comprehensive review will provide a guided tour through its basic principles, the development of artificial self-propelling microparticles and nanoparticles, and their application to the study of nonequilibrium phenomena, as well as the open challenges that the field is currently facing.

2,188 citations

Journal ArticleDOI
TL;DR: It is the view of the AES Task Force on the Phenotype of PCOS that there should be acceptance of the original 1990 National Institutes of Health criteria with some modifications, taking into consideration the concerns expressed in the proceedings of the 2003 Rotterdam conference.
Abstract: Objective: The Androgen Excess Society (AES) charged a task force to review all available data and recommend an evidence-based definition for polycystic ovary syndrome (PCOS), whether already in use or not, to guide clinical diagnosis and future research. Participants: Participants included expert investigators in the field. Evidence: Based on a systematic review of the published peer-reviewed medical literature, by querying MEDLINE databases, we tried to identify studies evaluating the epidemiology or phenotypic aspects of PCOS. Consensus Process: The task force drafted the initial report, following a consensus process via electronic communication, which was then reviewed and critiqued by the AES Board of Directors. No section was finalized until all members were satisfied with the contents and minority opinions noted. Statements that were not supported by peer-reviewed evidence were not included. Conclusions: Based on the available data, it is the view of the AES Task Force on the Phenotype of PCOS that...

1,877 citations

Journal ArticleDOI
TL;DR: The connection of AMPK with several tumour suppressors suggests that therapeutic manipulation of this pathway using established diabetes drugs warrants further investigation in patients with cancer.
Abstract: In the past decade, studies of the human tumour suppressor LKB1 have uncovered a novel signalling pathway that links cell metabolism to growth control and cell polarity. LKB1 encodes a serine-threonine kinase that directly phosphorylates and activates AMPK, a central metabolic sensor. AMPK regulates lipid, cholesterol and glucose metabolism in specialized metabolic tissues, such as liver, muscle and adipose tissue. This function has made AMPK a key therapeutic target in patients with diabetes. The connection of AMPK with several tumour suppressors suggests that therapeutic manipulation of this pathway using established diabetes drugs warrants further investigation in patients with cancer.

1,626 citations