Search PubMed⌕ Search

Biomedical subjects

B Probst

Publications and source records attributed to B Probst.

15 recordsLinked to original sources
PubMed1993

Urinary estradiol-17 beta excretion in common marmosets, Callithrix jacchus: diurnal pattern and relationship between creatinine-related values and excreted amount.

1. The diurnal pattern of urinary estradiol and creatinine excretion was investigated in order to evaluate the relationship between total estradiol excretion per day and the estradiol concentration or the estradiol-to-creatinine ratio from single urine samples in female common marmosets (Callithrix j. jacchus). 2. During a 36-day period, urine was collected from five adult female marmosets in 3-hr intervals during the light time of an LD 12:12 (400:0.1 lx) which corresponded to the animals' activity time. 3. Estradiol concentration was determined by radioimmunoassay after glucuronidase treatment and creatinine concentration was measured photometrically. 4. Concentration and amount of excreted estradiol, and the creatinine concentration showed a distinct diurnal pattern with significantly higher levels at the beginning of the activity time compared to later sampling times. 5. No diurnal pattern was present in the estradiol-to-creatinine ratio, but the difference between lower follicular and higher luteal phase levels of estradiol excretion remained significant in the 36-day period. 6. Correlation analyses revealed significantly positive correlations between the total estrogen mass excreted per day and the estradiol-to-creatinine ratio in "morning urine" samples. 7. Thus the estradiol-to-creatinine ratio of single urine samples collected at the beginning of the activity time provides a reliable estimate of total estrogenic output in this species. 8. Studies of the circadian pattern of urinary hormone excretion, however, require total urine sampling.

Animals↗
PubMed1992

Neural androgen receptors and scent marking of male gerbils: modulation by females.

The involvement of brain cytosolic androgen receptors in the female-induced increase in scent-marking behavior of male Mongolian gerbils was studied. Scent-marking activities and serum testosterone concentrations were measured in low-marking control males and in males with increased scent-marking activities, stimulated by the presence of conspecific females in the same room. For every individual male the concentrations and affinities of androgen receptors were determined in four parts of the brain, which contained the hippocampus, septum, corpus striatum, amygdala, stria terminalis, and the hypothalamus. Compared to the basal unstimulated period, the marking activities of male gerbils significantly increased 58% during the presence of female conspecifics in their housing room. The serum testosterone concentrations did not change significantly during female presence. The association constants of the cytosolic androgen receptors were higher in the female-stimulated males compared to isolated control males. In contrast, the cytosolic receptor concentration was reduced. The difference reached significance in one of the brain parts. Individual levels in scent-marking activities could not be explained by correlation with individual androgen receptor parameters. The present results suggest that increased androgen binding in the brain may be involved in the elevation of scent-marking activities in male gerbils, caused by urinary chemical signals of female conspecifics.

Androgens↗
PubMed1992

An automated method for recording scent marking in Mongolian gerbils.

A device for the automated recording of scent-marking events in Mongolian gerbils (Meriones unguiculatus) is described. The method uses minute temperature changes occurring at the surface of marked objects to detect scent marking. These events are recorded by a computer together with the exact time and the location of the marked object. The data obtained with this temperature-sensitive recording method correlate well with data obtained in parallel by human observers. The measurement of the diurnal rhythm of scent-marking behavior for 5 consecutive days in an undisturbed male demonstrates the specific usefulness of this new recording method. In addition, this temperature-sensitive automated recording of scent-marking behavior may also be applicable in other animals that primarily mark protruding objects.

Animals↗
PubMed1991

Quantitative characterization of hormone receptors by a nonlinear regression approach.

This paper describes a mathematical model for the quantification of receptors based only upon the total bound values as a function of the total ligand concentration. In contrast to methods relying on linearization transformations, this nonlinear model requires more sophisticated computation, however, avoids loss of material for determination of nonspecific binding in competed tubes. Monte-Carlo simulation indicated high stability of this model against random experimental error. The androgen receptor of the male gerbil (Meriones unguiculatus) ventral prostate is characterized using the described nonlinear computation.

Androgens↗
PubMed1990

[Social integration of Crohn disease and ulcerative colitis patients. Study of the relations of somatic, psychological and social factors].

63 patients with Crohn's disease and 58 patients with ulcerative colitis were tested with the "Fragebogen zur sozialen Integration" (FSI, questionnaire of social adjustment), the "Freiburger Persönlichkeitsinventar" (FPI) and a semistandardized interview and were compared with surgical controls. Activity, course and symptoms of the disease were registered. We found significant restrictions in working and lesiure activities, partnership and sexual life in patients with inflammatory bowel disease. Social adjustment of patients with Crohn's disease was more dependent on disease activity than in patients with ulcerative colitis. Social impairment in patients with Crohn's disease correlated with higher stool frequency and abdominal pain, in patients with ulcerative colitis with reduced general state of health, tiredness and limpness. In the "Freiburger Persönlichkeitsinventar" (FPI) the patients with chronic inflammatory bowel disease described themselves significantly more nervous, inhibited, reserved and less aggressive, sociable and composed. The FPI scores in patients with Crohn's disease depended more on disease activity and on somatic symptoms than in patients with ulcerative colitis.

Adolescent↗
PubMed1989

Mentor program for high school students.

As the nation grapples with the latest shortage of registered professional nurses, a creative solution, with an eye toward nursing in the 21st century, is the Mentor Program in Nursing for high school students at The Mount Sinai Medical Center in New York City. The registered professional nurses on staff at the medical center have made a commitment to this program as a way of encouraging a continuous supply of future nurses.

Career Choice↗
PubMed1987

Diurnal patterns of scent-marking, serum testosterone concentration and heart rate in male Mongolian gerbils.

The diurnal rhythms of scent marking behavior in an open-field test as well as the diurnal rhythms of serum testosterone concentration and heart rate under home cage conditions were investigated in male Mongolian gerbils. The behavioral measures of scent marking activity, sniffing frequency and locomotor activity in the open field showed a clear rhythm during the 24 hour period with a significant maximum during the dark. In contrast to this, the mean testosterone concentration was lower during the dark as compared to the light phase. The heart rate was not different during light and dark phase of the diurnal cycle, instead, bursts of increased frequency occurred approximately once per hour, both during light and dark phase.

Animals↗
PubMed1987

Developmental changes in the pituitary-gonadal-axis in male Mongolian gerbils from birth to adulthood.

The development of the pituitary-gonadal-axis and of body and organ weights was investigated in male Mongolian gerbils. During the neonatal period from birth to 7 days of age testicular activity was high but decreased to low prepubertal levels from 7 to 28 days of age. The pubertal period occurred from 1 to 3 months of age and was characterized by an intense rise in serum testosterone concentrations and in testicular testosterone production in-vitro. At 2.5 months of age accessory organs achieved their adult weight, at the same time as both, serum testosterone concentration and in-vitro testosterone production, reached their respective maximum levels. From 4 until 24 months of age no further relevant changes occurred in the pituitary-gonadal-axis. This study demonstrates that the testicular responsiveness is an important factor for the pubertal increase of testosterone during sexual maturation of male Mongolian gerbils.

Animals↗
PubMed1985

Individual marking activities not reflected by respective testosterone levels in male gerbils.

The hormonal regulation of scent marking behavior in the male Mongolian gerbil was studied. Experiment 1 investigated the developmental patterns of testosterone concentration and scent marking. Concurrent serum samples were repeatedly obtained, by venipuncture, from the same individuals that were used for behavior testing. Experiment 2 studied the relationship between testosterone and marking behavior in individual males before and during castration and after testosterone replacement. Repeated blood sampling did not influence body weight and marking activity as compared to the controls. Despite a high correlation between weekly mean measures of testosterone and marking activity during development no such correlation was observed on the individual level. That means that individual testosterone concentrations did not reflect individual differences in marking activity. After castration scent marking activities decreased. Testosterone treatment restored marking activities to the individual maximum levels observed during puberty; however, even high doses of testosterone did not equalize individually different marking activities. It is suggested that the individual levels of behavioral activity are fixed during perinatal development, possibly through the action of testosterone or its metabolites.

Animals↗
PubMed1983

Comparison of LH stimulated testosterone release from Mongolian gerbil and mouse whole testes and isolated interstitial cells in vitro: difference in response and sensitivity.

The in vitro steroidogenic response of gerbil and mouse whole testes and isolated testicular interstitial cells to stimulation with gonadotrophic hormones was compared. The testosterone release during incubation in vitro with LH/FSH was measured radioimmunologically. In whole testes incubation, basal testosterone release after 4 h was significantly lower in gerbil as compared to mouse testes, but the testosterone release on maximal LH-stimulation was not significantly different. The increment in the testosterone production from basal to stimulated levels was greater in gerbil, the production per gram testis was greater in mouse testes. Mechanically dispersed interstitial cell preparations from gerbil and mouse released comparable amounts of testosterone during in vitro incubation. The lowest effective standard-concentration was 1.1 microIU LH/vial in gerbil and 35.9 microIU LH/vial in mouse interstitial cell incubations. Half-maximum testosterone release (ED50) occurred at 8-15 microU LH/vial for gerbil and 86-200 microIU LH/vial (ranges) for mouse interstitial cells. The difference in sensitivity to LH stimulation of gerbil and mouse interstitial cells is approximately 13-fold allowing the application of the gerbil interstitial cell assay to studies dealing with very small samples or little bioactive LH-concentrations.

Animals↗
PubMed1982

Corticosteroid, catecholamine and glucose plasma levels in rabbits after repeated exposure to a novel environment or administration of (1-24) ACTH or insulin.

The responsiveness of the adrenal cortex and the sympatho-adrenal-medullary system to stress factors and administration of (1-24) ACTH and insulin was studied in adult rabbits. In comparison to untreated animals, exposure to a novel environment for 10 min followed by artery puncture on 6 consecutive days elicited a moderate increase of corticosteroid (C), norepinephrine (NE) and epinephrine (E) plasma levels. Intramuscular injection of 50 micrograms/kg body weight (1-24) ACTH increased C, NE and E plasma levels. Saline injection resulted in elevated NE levels; C, E and glucose remained unchanged. After injection of 1.0 IU/kg body weight insulin C levels were higher than those found after exposure to a novel environment for 10 min followed by artery puncture; similarly, NE and E increased. In accordance with results obtained in the rat or mouse the sympatho-adrenal-medullary system in the rabbit is stimulated by stress factors such as handling, artery puncture or injection of (1-24) ACTH or insulin. In contrast the adrenal cortex can be stimulated only to a certain extent by these manipulations. An increased activation of adrenal cortex cells occurs only after insulin, a maximum stimulation only after (1-24) ACTH administration.

Adrenal Cortex Hormones↗
PubMed1982

Simultaneous release of androgens and progesterone by gerbil (Meriones unguiculatus) dispersed testicular interstitial cells under basal conditions and after stimulation with luteinizing hormone.

The production of androgens and progesterone by dispersed gerbil interstitial cells was studied in vitro. Incubation of 80,000-100,000 cells with 2.3-143.8 microIU LH/vial resulted in a 1.9-8.0 fold increase of androgen and in a 2.2-19.8 fold increase of progesterone release. The ratio of androgens/progesterone released by gerbil interstitial cells was 8.1 in the absence of LH, and was significantly higher in the presence of 143.8 microIU LH/vial (17.7). In all cell assays performed (n = 5), a highly significant positive correlation between LH-stimulated androgen and progesterone release was found. In comparison with androgen biosynthesis in vitro in either the rat or mouse, gerbil, interstitial cells are much more sensitive to LH as argued from both androgen and progesterone release. The reason for this high responsiveness of gerbil interstitial cells is not clear; it may be due in part to the very low bioactive LH levels in gerbils leaving a major part of LH receptors unoccupied thus allowing even trace amounts of LH to fully activate steroidogenesis.

Androgens↗
PubMedDate not supplied

Female urinary chemosignals influence scent-marking behavior in male Mongolian gerbils (Meriones unguiculatus).

The influence of females on the amount of scent-marking behavior displayed by male Mongolian gerbils was investigated. Males isolated from females scent mark at a low level which increases more than two-fold if females are present in the room for three weeks without direct contact with the males. A similar increase is obtained by application of pooled female urine directly onto the males' noses.

Animals↗