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Biomedical subjects

G Dörner

Publications and source records attributed to G Dörner.

At least 127 records · Page 7Linked to original sources
PubMed1982

Responses of salivary cortisol levels to stress-situations.

A procedure is described for determining salivary cortisol levels by a competitive protein-binding assay using horse transcortin. The collection of saliva was performed by means of filter paper-strips. Filter paper samples are more than 5 days stable after air-drying. In this form, the samples could be stored without refrigerator or deep-freezer and, if necessary, sent by post to the laboratory without any special precaution. Stressful situation of either painful or anxious origin were associated with an adequate increase of salivary cortisol levels. The increases were 157 to 230% of the initial or normal values dependent on the kind of stress. The mean values in 4 cases of Cushing's syndrome were 380% and 1 hour after 25 I.U. ACTH 690% higher than those in normal persons. In normal persons, a well-defined circadian rhythm has been observed.

Adrenocorticotropic Hormone↗
PubMed1982

Enzyme immunoassay of 17-hydroxyprogesterone in plasma, microfilter paper blood and saliva of newborns, children and patients with congenital adrenal hyperplasia.

An enzyme immunoassay for the measurement of 17-hydroxyprogesterone (OHP) is described. The antigens, OHP-3-CMO-BSA and 11-deoxycortisol-21-hemisuccinate-BSA have been used to produce antisera in rabbits. The enzyme marker was horseradish peroxidase. Bound/free separation was achieved by the double antibody/polyethylene glycol method. The method was used for plasma samples, capillary blood dried on paper disc and for saliva. The normal values for OHP in newborns and children were determined. This method makes possible a selected screening program for congenital adrenal hyperplasia in the newborns.

17-alpha-Hydroxyprogesterone↗
PubMed1982

Perisuprachiasmatic lesions enhance the increase of gonadotropin secretion in acutely ovariectomized rats.

Diestrous female rats were bilaterally lesioned in the perisuprachiasmatic region (peri-SCN region) or in the medial preoptic area (MPOA) and ovariectomized immediately after lesioning. Blood was collected at one hour before and at 4.24 and 48 h after surgery. Radioimmunological determination of the serum gonadotropin concentrations revealed that lesioning of the peri-SCN region enhanced significantly the castration-induced increase of FSH and LH secretion at 4 and 24 h, whereas MPOA lesions did not influence the serum hormone levels as compared to the sham-lesioned controls. The findings suggest that the peri-SCN region, but not the MPOA may be involved in the control of the increase of gonadotropin secretion following ovariectomy in rats.

Animals↗
PubMed1982

Acetylcholine concentrations in the developing brain appear to affect emotionality and mental capacity in later life.

A decrease of the acetylcholine concentration in the brain of infantile rats was induced by maternal deprivation in neonatal life, which was associated with emotional and mental ill-effects in later life. The decreased acetylcholine concentration in the infantile brain as well as the permanent emotional and mental ill-effects, which were produced by neonatal deprivation, could be prevented by neonatal administration of the acetylcholinesterase inhibitor pyridostigmine. These findings suggest that acetylcholine can be considered as an important, environment-dependent local organizer of the brain.

Acetylcholine↗
PubMed1981

Sex hormones and neurotransmitters as mediators for sexual differentiation of the brain.

Sexual differentiation of the brain is regarded as a model for environment-dependent brain development mediated by systemic hormones and neurotransmitters. Abnormal concentrations of systemic hormones and/or neurotransmitters, if occurring during a critical period of brain development, can lead to permanent developmental disabilities of fundamental processes of life. Such developmental disabilities appear to be avoidable, at least in part, by improving the external, i.e. psychosocial and natural environment, or by correcting abnormalities in the internal, i.e. metabolic and hormonal environment and, particularly, by correcting abnormal neurotransmitter concentrations (and/or turnover rates) during brain development.

Acetylcholinesterase↗
PubMed1981

Further studies on the hypothalamic desensitization to estrogen in immature female rats: evidence for a possible role in the control of puberty.

Immature and puberal female rats were ovariectomized and implanted with estradiol benzoate and cholesterol at the ratios of 1:120 or 1:240 into the hypothalamic ventromedial-arcuate region at 26 or 32 days of age, or on the day of the first vaginal estrus. Evaluation of the serum LH and FSH concentrations on the 2nd day after implantation revealed that the gonadotropin-inhibiting effect of the locally administered estrogen decreased between days 26 and 32 and showed a further distinct decline at the time of puberty. In a second experiment, uterine weight and serum LH and FSH levels were monitored in untreated immature female rats at daily intervals from 25 to 36 days of age. Relatively high values for both gonadotropins were recorded between days 25 and 28. Accelerated uterine growth around day 30 indicating increasing estrogen secretion was associated with a sudden decrease of LH and FSH concentration in the blood. After that, LH and, to a less degree FSH levels began to rise in spite of further weight gain of the uterus. The results suggest that the hypothalamic sensitivity to the gonadotropin-inhibiting effect of estrogen declines during the last week before the onset of puberty. Together with other findings they furthermore indicate that this desensitization process may be involved in the neurohormonal control of puberty in female rats.

Animals↗
PubMed1981

Failure to demonstrate a significant influence of ovarian maturity on the onset of puberty in female rats.

Ovaries of 23- and 35-day-old rats were transplanted under the kidney capsules of 31- and 23-day-old females, respectively. The recipient rats were ovariectomized on the fourth day after transplantation, and the onset of puberty was recorded. Neither the age and body weight at vaginal opening and first ovulation nor the length of the first ovarian cycle differed significantly between the experimental rats and sham-transplanted or untreated controls. Estimation of the serum FSH an LH concentrations before and after ovariectomy provided no evidence that different gonadotropic responses had masked puberty-delaying or puberty-advancing effects of the implanted immature and prepuberal ovaries, respectively. The results suggest that the developmental stage of the ovaries is not a decisive factor in the control of the onset of female puberty.

Animals↗
PubMed1981

Enzyme immunoassay and radioimmunoassay for plasma renin activity. I. Comparison of the methods.

Sensitive and specific enzyme and radioimmunoassays have been developed for the determination of renin activity. These methods are based upon the determination of angiotensin I generated by endogenous renin and angiotensinogen. An antibody trapping technique was used, while the addition of chemicals to the plasma, used until now as inhibitors for converting enzyme and angiotensinases, was eliminated. The angiotensin I was labelled with horseradish peroxidase for enzyme immunoassay and with iodine-125 for radioimmunoassay. Antibody bound and free labelled antigen were separated from each other by a second antibody polyethyleneglycol method (enzyme immunoassay) and by charcoal-dextran adsorption (radioimmunoassay). The values of renin activity in human plasma determined by enzyme immunoassay correlated well with those obtained by radioimmunoassay.

Adult↗
PubMed1981

Enzyme immunoassay for plasma renin activity: II. Clinical application.

The application of an enzyme immunoassay for plasma renin activity in clinical diagnosis was studied and the following findings were obtained: 1. In patients with primary aldosteronism, very low renin activities were found. On the other hand, increased renin levels were observed in patients with secondary aldosteronism (renal artery stenosis, malignant hypertension, Bartter's syndrome). 2. Plasma renin activity was found to be considerably increased in Addison's disease. Measurements of Plasma renin were a guide-line for appropriate mineralocorticoid substitution in those patients. In 6 patients with salt-losing congenital adrenal hyperplasia due to 21-hydroxylase deficiency, the renin activity was also elevated and normalized after corticoid treatment. 3. During pregnancy, the renin levels showed an increasing tendency from the first to third trimester. Women with pre-eclampsia showed higher values than normal pregnant women. 4. An age-dependent change of renin activity was observed in newborns and children, especially markedly increased values during the first 5 days of life. 5. During the normal menstrual cycle the renin levels increased to a maximum in the mid-luteal phase. A significant increase of renin activity was found in women taking oral contraceptives. Previously, we reported on the determination of renin activity by an enzyme immunoassay (EIA) (Hubl et al., 1980). In this study, we examined the clinical application of this EIA.

Addison Disease↗
PubMed1981

Pyridostigmine administration in newborn rats prevents permanent mental ill-effects produced by maternal deprivation.

Maternal deprivation from Day 3 to Day 14 of life, i.e., separation of the pups from their mother animals during this developmental period for 16 hours each day, gave rise to highly significantly decreased learning capability and memory capacity in adulthood associated with significantly decreased acetylcholinesterase activity in the brain. These permanent ill-effects of the brain, produced by maternal deprivation of newborn rats, could be prevented by the acetylcholinesterase inhibitor pyridostigmine when administered from Day 1 to Day 14 of life. In view of these findings, teratogenic mental ill-effects, produced by psychosocial and/or nutritional deprivation during brain development, appear to be preventable by correcting abnormal neurotransmitter concentrations during this critical period of brain organization.

Acetylcholinesterase↗
PubMed1981

Effects of neonatal pyridostigmine treatment on sexual maturation and adult behaviour in female rats subjected to maternal deprivation.

The present study deals with the effects on adult behaviour of early postnatal maternal, i.e. psychosocial and/or nutritional deprivation and of altering the brain levels and/or turnover rates of acetylcholine in preweaning deprived rats. The following data were obtained: 1. Female rats separated from their mothers and littermates for 16 hours each day during the first two weeks of life showed a significant delay of puberty onset in comparison with non-separated controls. Furthermore, these animals exhibited significantly reduced emotionality as well as learning capability and memory capacity in adulthood. 2. Administration of the acetylcholinesterase inhibitor pyridostigmine during the first two weeks of life to the deprived females did not compensate the puberty-delaying effect of separation. However, the neonatally pyridostigminized female rats exhibited an increased emotional reactivity in adult life. 3. Female rats deprived from their mothers and treated with pyridostigmine during the neonatal period displayed increased avoidance learning and memory capacity in adulthood as compared to neonatally deprived but untreated animals. It might be concluded from our results that defects of brain differentiation produced by early postnatal deprivation could be prevented, at least in part, by simultaneous administration of pyridostigmine.

Acoustic Stimulation↗
PubMed1980

Androgen-dependent sexual dimorphism of the immune system.

An androgen-dependent sexual dimorphism of the immune system was demonstrated in mice. The ration of T/B lymphocytes in the spleen was found to be significantly higher in adult females than in adult males. Furthermore, neonatal androgen administration in females gave rise to a permanent significant decrease of the T/B ratio, while neonatal castration in males resulted in a permanent increase of this ratio.

Animals↗
PubMed1980

Evidence for direct central nervous inhibition of LH secretion during sexual maturation of female rats.

Intact and ovariectomized female rats were bilaterally lesioned in the anterior part of the medial amygdaloid nucleus (AMN) at 15, 21 or 26 days of age. The onset of puberty and the LH concentration in the peripheral serum on the third day after lesioning, respectively, were recorded. Damage to the AMN on day 15 induced a significant delay of vaginal opening and the first puberal ovulation and suppressed completely the castration-induced increase of LH secretion. In contrast, females lesioned on day 21 showed true precocious puberty and a significant elevation of the LH level as compared to the ovariectomized controls. The LH-inhibiting effect of s.c. administered estradiol benzoate (0.05 micrograms/100 g/day) was not diminished by lesions produced at this age. Neither the onset of puberty nor the LH concentration were influenced by lesioning of the AMN on day 26. Estimation of the LH concentration in untreated female rats revealed a distinct decline between 19 and 23 days of age followed by a significant increase between days 24 and 26. The findings indicate a transient LH-inhibiting activity of the medial amygdala in three-week-old female rats that is not related to the negative estrogen feedback. In other species, too, a temporary inhibitory action of the central nervous system may play a significant role in the prepuberal control of gonadotropin secretion.

Aging↗