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Biomedical subjects

R M Levin

Publications and source records attributed to R M Levin.

At least 325 records · Page 18Linked to original sources
PubMed1979

Plasma estradiol window and urinary estriol glucuronide determinations for monitoring menotropin induction of ovulation.

The plasma estradiol response is maximal 8--10 hours following mentropin injection. To obtain closer control, a menotropin protocol using 5 PM--8 PM injections and 8 AM blood sampling with a plasma estradiol window of 1000--2000 pg/ml was evaluated with simultaneous calibration of a urinary estriol glucuronide radioimmunoassay. One hundred twenty-eight paired urine and plasma samples were assayed in 48 cycles. In 26 cycles with paired samples on the day of human chorionic gonadotropin (hCG) injection, there were no cases of severe hyperstimulation, 2 cases of moderate hyperstimulation, and 11 pregnancies (42% of cycles given hCG). A window of between 40 and 100 micrograms/day of urinary estriol glucuronide corresponded to the 1000--2000 pg/ml plasma estradiol window by regression analysis. The pregnancy and hyperstimulation rates were compared with those observed in protocols previously published. Radioimmunoassay of urinary estriol glucuronide is faster and simpler than radioimmunoassay of plasma estradiol.

Abortion, Spontaneous↗
PubMed1978

Specificity of the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase and to a series of other calcium-binding proteins.

Trifluoperazine inhibits the activation of phosphodiesterase by binding to the calcium-dependent activator. To determine further the specificity by which trifluoperazine binds to activator, we compared the binding of trifluoperazine to activator prepared from several species and tissues and to a number of other calcium-binding proteins devoid of activator activity. Trifluoperazine binds to activator prepared from human, bovine, rat and rabbit brain and from chick embryo fibroblasts. In each case, the binding of trifluoperazine to activator was qualitatively similar and related quantitatively to the ability of the preparation to activate phosphodiesterase. Of the other calcium-binding proteins examined, namely, troponin-C, S-100 protein, phospholipase A, phospholipase B and myosin light chain, only troponin-C displayed any significant calcium-specific binding of trifluoperazine. The binding to troponin-C, however, appeared to be different from the binding to activator; whereas the binding of trifluoperazine to actovator showed no cooperativity, the binding to troponin-C showed positive cooperatively. These results and earlier data showing that trifluoperazine fails to bind to a variety of other proteins, indicate that the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase is selective and suggest that this binding may explain some of the biochemical and pharmacological actions of this antipsychotic agent.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1977

A direct radioimmunoassay for estriol-16-glucuronide in urine for monitoring pregnancy and induction of ovulation.

Antibodies to estriol-16alpha-[beta-D-glucuronide] were raised in sheep with the use of keyhold limpet hemocyanin and bovine serum albumin conjugates of estriol-16alpha-[beta-D-glucuronide]. A simple, rapid method is presented for direct radioimmunoassay of estriol-16alpha-[beta-D-glucuronide] in urine with dextran-coated charcoal used for separation of free from bound and deionized water used for dilutions. The method is thrifty in its use of reagents. The assay has been evaluated in the pregnancy range, and the sensitivity has been extended into the range necessary for monitoring induction of ovulation with Pergonal.

Animals↗
PubMed1977

The effect of angiotensin II and indomethacin on uterine artery blood flow in pregnant monkeys.

In experiments performed in anesthetized monkeys in the third trimester of pregnancy, mean maternal arterial blood pressure was continuously monitored, the uterine artery blood flow was measured with an electromagnetic flow probe, and prostaglandin levels were assayed in the uterine venous effluent. After inhibition of prostaglandin systhesis with indomethacin, the mean arterial blood pressure in response to angiotensin II was greater than the response prior to indomethacin treatment, and an increase in uterine artery blood flow was prevented. These findings are consistent with the suggestion that prostaglandins mediate the uterine artery blood flow response to angiotensin II, as well as modifying the maternal systemic blood pressure response.

Angiotensin II↗
PubMedDate not supplied

Simultaneous onset of alopecia areata and idiopathic thrombocytopenic purpura: A potential association?

Alopecia areata (AA) has been associated with a variety of autoimmune diseases. Immune thrombocytopenic purpura (ITP) is an autoimmune disease marked by isolated thrombocytopenia. We present a young girl with the simultaneous onset of AA and ITP. To the best of our knowledge, this association has not previously been reported. We hypothesize that ITP may be one of many autoimmune diseases associated with AA via antibodies that cross-react between platelet membrane glycoproteins and follicular glycoproteins.

Alopecia Areata↗
PubMedDate not supplied

ATP concentration of human spermatozoa: lack of correlation with sperm motility.

The primary source of energy for sperm motility is intracellular adenosine 5'-triphosphate. We studied the relationship between the concentration of ATP and sperm motility in normal semen donors and in a series of male infertility patients. The ATP concentration was determined by the firefly luciferin-luciferase assay, and sperm motility was quantitated by the turbidimetric method. Although the patient population demonstrated a significantly lower sperm motility than the donor population, we found no significant difference between the two groups in the intracellular concentration of ATP. Thus, the data indicate that the poor sperm motility observed in some of the patients' specimens was not associated with abnormally low levels of ATP. In separate experiments the intracellular concentration of ATP decreased gradually with time at approximately the same rate at which sperm motility declined. Both factors had decreased by 50% approximately 3 hours after collection.

Adenosine Triphosphate↗
PubMedDate not supplied

Clinical use of the turbidimetric analysis of sperm motility: an update.

The turbidimetric method of sperm motility analysis provides a quantitative measure of sperm motility. We have previously reported the methodology by which this method is utilized in routine sperm motility determinations in our Male Fertility Clinic. We have recently observed that the motility of sperm in dialyzed seminal plasma is over double the motility in Lopata's medium. This report provides quantitative evidence that the use of dialyzed seminal plasma in the turbidimetric analysis is significantly superior than the use of Lopata's medium.

Dialysis↗
PubMedDate not supplied

Ketamine-pancuronium-narcotic technic for cardiovascular surgery in infants--a comparative study.

Ketamine, pancuronium, and alphaprodine were used as the primary anesthetic agents in 71 infants requiring cardiovascular operations during a recent 1-year period. This group of patients was compared with a similar group anesthetized 3 years before with d-tubocurarine, halothane, and/or N20-O2. Stability of the circulatory system was well maintained with ketamine-pancuronium-narcotic (KPN) during the induction period. However, once surgical dissection of the heart and great vessels began, hypotension/bradycardia, ventricular fibrillation, and 48-hour mortality were similar for the two groups. Therefore, using these criteria for analysis, the KPN technic, in spite of claims for its minimal adverse effect on the cardiovascular system, did not prove superior to the halothane-N2O-O2-curare technic.

Alphaprodine↗
PubMedDate not supplied

Comparative study of two computerized semen motility analyzers.

Semen analysis is one of the primary tests carried out to investigate the infertile male. Subjective evaluation of semen is often prone to observer bias and error. To eliminate this, a number of computerized semen analyzers have recently been introduced into the market and we have evaluated two of the more popular models, the Cell Soft Semen Analyzer and the Hamilton Thorn Motility Analyzer (HTM 2000). The Cell Soft identifies sperm on the basis of user defined values for cell size and luminosity whereas the Hamilton Thorn identifies sperm by motility, and then applies the computer-calculated average size and luminosity of all moving objects to non moving sperm cells. Semen samples from 25 normal donors and 25 subfertile patients were analyzed using these two models of computerized semen analyzers, and also by an experienced technician using both the Makler chamber and the hemocytometer. The results obtained from the two automated analyzers were compared with those obtained by subjective evaluation. Variation in sperm count and motility were analyzed according to the sperm density. Four groups, less than 30 million/ml with debris, less than 30 million/ml, 30-50 million/ml, and greater than 50 million/ml were studied. The majority of patients fit into the first two groups. We observed that the HTM 2000 is superior to the Cell Soft in evaluating sperm count within the patient population group. For our donor population with an average sperm count of greater than 85 million/ml both systems provide extremely accurate counts.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗