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Biomedical subjects

G Weiss

Publications and source records attributed to G Weiss.

At least 307 records · Page 17Linked to original sources
PubMed1986

Effect of relaxin on human spermatozoa.

To study its effect on the motility of human spermatozoa, relaxin was added at different concentrations to human semen samples of various qualities as well as to washed spermatozoa. Relaxin in physiologic concentrations (10-100 ng/mL) had no significant effect on sperm motility in normal semen samples. However, the addition of relaxin to semen samples with low sperm motility significantly increased the motility. Addition of relaxin similarly increased the motility of spermatozoa from normal semen samples that were either aged or washed; the treatment resulted in a decrease in motility. When sperm motility was optimal, as in normal samples, addition of relaxin did not increase motility. However, in some situations of decreased motility, addition of relaxin resulted in improvement of spermatozoan motility. Relaxin may have clinical value in the treatment of male infertility.

Animals↗
PubMed1985

Solubilization and reconstitution of the membrane-bound carotenogenic enzymes from daffodil chromoplasts.

The membrane-bound carotenogenic enzymes of daffodil (Narcissus pseudonarcissus) chromoplast membranes, i.e. dehydrogenation, cis-trans isomerization and cyclization activities, were solubilized in an enzymatically inactive form using the zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylamino]-1-propanesulfonate (Chaps). Full enzymatic activities were regained upon reconstitution of the solubilized proteins into liposomes. These preparations converted radiolabelled cis-phytoene into beta-carotene in a high yield. The reconstituted enzymatic sequence behaved as a tight 'assembly line'. In the enzymatic sequence of the reconstituted system the cis-trans isomerization reaction occurred on the stage of cis-phytofluene after a dehydrogenation of cis-phytoene.

Biotransformation↗
PubMed1985

The effect of relaxin on the motility of sperm in freshly thawed human semen.

In an attempt to improve the motility of thawed spermatozoa after 1 week of its being frozen, we treated ten normal semen samples with 16.7 nmol relaxin and 6 mmol caffeine. Motility and grade of forward progression were examined after thawing. Caffeine significantly improved motility of spermatozoa. Relaxin, when added to semen at the time of thawing, improved motility and grade of forward progression significantly. This effect was not seen if relaxin was added before freezing. These results suggest that the biologic activity of relaxin is adversely affected by freezing and thawing in seminal plasma. These observations may have clinical importance for the improvement of motility of frozen spermatozoan samples at the time of artificial insemination and for the possible improvement of pregnancy rates.

Caffeine↗
PubMed1985

The use of voided urine temperature in the determination of basal body temperature.

The temperature of freshly voided urine has been shown to be a reliable predictor of body temperature. This relationship was confirmed for the measurement of BBT. A method was described for patients to obtain their BBT in a way that they may find more convenient than obtaining either oral or rectal temperature. The BBT graph patterns generated from the temperature of freshly voided urine closely paralleled those generated by oral temperature.

Body Temperature↗
PubMed1985

The effect of iron on in vitro decalcification of human tooth enamel.

The effect of iron chloride on an in vitro acid attack of human enamel was studied. Slices of teeth were covered with varnish except for a window left on one of the enamel surfaces for exposure. The iron salt was used as a supplement to acid gel, or as pretreatment of the enamel surfaces before exposure to the pure gel. Differences in light transmission of the experimental and control specimen from the radiographs taken before and after immersion in the decalcifying media were assessed quantitatively. The increase in radio-opacity of the enamel sections incubated in the iron-containing acid media was attributed to a lower degree of enamel decalcification.

Acids↗
PubMed1985

Relaxin in the pregnant baboon: evidence for local production in reproductive tissues.

We examined the nonluteal production of relaxin in the pregnant baboon. In experimental animals (n = 5), the corpus luteum-bearing ovary was removed in early pregnancy (days 25-30), and intact pregnant baboons served as controls. In both groups of baboons, peripheral, uterine, and ovarian venous blood samples and amniotic fluid were collected immediately before hysterotomy, which was performed late in pregnancy (days 139-142). After hysterotomy, samples of reproductive and control tissues were obtained (placenta, decidua, myometrium, fetal membranes, and omentum). Relaxin concentrations were determined in all samples using an antiporcine relaxin RIA. In unilaterally oophorectomized pregnant baboons, peripheral plasma levels of relaxin were below the limits of detection (less than 157 pg/ml) for 100 days following corpus luteum removal, while levels in control pregnant baboons were greater than 1000 pg/ml. Relaxin levels in uterine venous plasma were comparable to peripheral plasma levels in each group. Relaxin concentrations in amniotic fluid of both groups were below the limits of detection (less than 157 pg/ml). Relaxin was found in decidua, placenta, and myometrium in those pregnant baboons in which the corpus luteum-bearing ovary had been removed over 100 days earlier. This finding together with the absence of a relaxin gradient in uterine venous plasma and undetectable relaxin levels in amniotic fluid is a strong indication of local relaxin production in reproductive tissues without contribution to peripheral plasma levels.

Amniotic Fluid↗
PubMed1985

The winds of change: medical staff relations.

Are hospital governing boards and medical staffs natural adversaries in the health care ecosystem, or are they partners in a common effort? Are they parallel but equal organizations with different roles and different points of view, or, eventually, must one emerge with authority over the other? This article discusses how medical staff/board relations are changing and the need for better communications between the two leadership groups.

Communication↗
PubMed1985

Simultaneous occurrence of idiopathic lipemic tears and massive seborrhea.

A 42-year-old man had idiopathic lipemic tears and massive seborrhea. Recent investigations have shown that cholesterol and other lipids occasionally found in tears are produced by meibomian rather than lacrimal glands. The finding in this patient of hypersecretion by both sebaceous glands and meibomian glands, a sebaceous gland variant, suggests that a common mechanism may regulate secretory control of both of these glands.

Adult↗
PubMed1985

Human tumor cloning assay: clinical applications for ovarian, gastric, pancreatic, and colorectal cancers.

In this investigation, the human clonogenic assay is used as a tool to identify which chemotherapeutic agents may be of interest for intraperitoneal administration. Both conventional and investigational agents are examined in ovarian, colorectal, pancreatic, and gastric carcinomas. Scattergrams plotting the in vitro percent response against the in vivo percent response provide some clinical correlation with the observed in vivo antitumor activity. In addition, anticancer agents are identified for which evidence of a dose-response relationship is observed in the clonogenic assay. Such evidence is offered as the basis for the choice of agents that may be useful for intraperitoneal administration.

Antineoplastic Agents↗
PubMed1985

Hyperactivity. Overview and new directions.

An enormous number of articles have been published in recent years on this most researched and best known of the childhood behavior disorders. This article discusses the syndrome of hyperactivity in terms of postdictive, concurrent, and predictive validity. Future research is considered and follow-up studies are reviewed.

Adolescent↗
PubMed1985

Elevated serum relaxin levels in multiple pregnancy after menotropin treatment.

The serum relaxin and human chorionic gonadotropin (hCG) concentrations were determined in 17 spontaneous singleton pregnancies and four singleton pregnancies and five multiple gestations that followed treatment with menotropins. The geometric mean serum relaxin concentrations for the control and postmenotropins singleton pregnancies were similar (both 1.13 ng/mL), but the geometric mean serum relaxin concentration for multiple gestations that followed treatment with menotropins was significantly higher (2.56 ng/mL, P less than .01). A significant regression of serum relaxin on either days from the last menstrual period or serum hCG concentration was demonstrated. Covariance analysis supported the conclusion that multiple gestation produced a significant increase in serum relaxin concentration.

Chorionic Gonadotropin↗
PubMed1985

Relaxinlike bioactivity in pooled human pregnancy serum.

The purpose of this study was to determine whether or not the immunoreactive relaxin contained in human pregnancy serum is biologically active. Relaxin was extracted from pooled serum of women in the third trimester of pregnancy. The extraction also was performed on pooled male serum and pooled serum from women in the follicular phase of the menstrual cycle. The extraction process began with delipidation of the serum followed by extraction of relaxin using 0.1% HCl per 50% acetone. Dialysis then was performed to remove low molecular weight substances (less than 3500 daltons). The partially purified extracts were applied individually to a muscle segment in the in vitro rat uterine horn bioassay for relaxin. The extracts of both male serum and female follicular-phase serum, containing no immunoreactive relaxin, resulted in tetanic contractions of the muscle segment. The extract of pregnancy serum, containing immunoreactive relaxin, produced inhibition of rat uterine horn contractility. This represents the first demonstration of relaxinlike bioactivity in human serum.

Animals↗
PubMed1985

Hyperprolactinemia and associated pituitary prolactinomas.

The association between serum prolactin (PRL) and the presence of pituitary tumors as determined by third generation computed tomography scan was studied in hyperprolactinemic patients. Patient charts from a four-year period were reviewed to identify those patients with elevated PRL (greater than or equal to 25 ng/mL). All patients with hyperprolactinemia underwent computed tomography scan evaluation of the pituitary gland. Hyperprolactinemia was identified in 79 patients, mean PRL 59 +/- 6.1 ng/mL SEM. Pituitary tumors were identified in 35 of these patients, mean PRL 65 +/- 11.9 ng/mL. This level was not significantly different from the level in 43 patients with normal computed tomography scans (52 +/- 5.7 ng/mL). This review found that computed tomography scan identified pituitary tumors in 44% (35 of 79) of patients with hyperprolactinemia. The likelihood of finding a pituitary tumor did not correlate with the level of hyperprolactinemia. Computed tomography scan is indicated for the diagnosis of prolactinomas in all hyperprolactinemic patients regardless of the serum PRL level.

Adenoma↗