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T Ertl

Publications and source records attributed to T Ertl.

At least 37 records · Page 2Linked to original sources
PubMed1993

Spontaneous and gonadotropin-releasing hormone induced human chorionic gonadotropin release from superfused JAR choriocarcinoma cells.

JAR choriocarcinoma cells have retained several characteristics of normal trophoblasts and have been used as an in vitro trophoblast model. The superfusion system is suitable for the study of hormone synthesis and/or secretion. JAR cells were cultured and transferred to the superfusion system in order to evaluate the spontaneous hCG secretion and the effect of GnRH. The spontaneous hCG release showed a periodic pattern with a 48 min phase interval. In our system single cells and cell-clusters were superfused and there is a possibility that cell to cell connections might have an influence on the regulation of hormone synthesis and/or secretion. GnRH in 4 x 10(-7) M and 4 x 10(-6) M concentrations or 100 mM KCl caused an immediate hCG release from the JAR cells Repeated administration of GnRH resulted in a delayed hCG release which is probably related to the relatively small amount of hCG available from the storage granules or to the phase of spontaneous secretion.

Cell Line↗
PubMed1993

Preliminary report on the application of pulsed CO2 laser radiation on root canals with AgCl fibers: a scanning and transmission electron microscopic study.

Fifteen maxillary central incisors were treated in vitro with pulsed CO2 laser radiation (wavelength:9.6-microns pulse duration:135-microseconds pulse energy:60 mJ energy density:12 J/cm2) delivered by an AgCl fiber into the root canal. Preliminary results show opening of dentin tubules as well as fused areas of hydroxyapatite in the root canal after laser treatment. Temperature measurement at the root surface showed that 40 degrees C was not exceeded. These preliminary results show the ability of this laser system to open dentin tubules and to fuse hydroxyapatite but further development in fiber technology is necessary to achieve predictable results.

Carbon Dioxide↗
PubMed1993

Influence of NaCl supplementation on vasopressin secretion and water excretion in premature infants.

The study was carried out to assess the possible involvement of excess AVP and free water retention in the development of late hyponatremia by comparing the postnatal course of plasma AVP and urinary excretion of AVP and sodium as well as creatinine, osmolar and free water clearances in premature infants with (group S) and without (group NS) NaCl supplementation. Plasma total protein and albumin concentrations were also determined. Group NS consisted of 8 infants with a birth weight of 1,150-1,730 g (mean: 1,440 g) and gestational age of 28-32 weeks (mean: 30.4 weeks). Group S included 8 infants with a mean birth weight of 1,390 g (range: 980-1,700 g) and a mean gestational age of 30.1 weeks (range: 27-32 weeks). Measurements were made on the 7th day and weekly thereafter until the 5th week of life. NaCl supplementation was given in a dose of 3-5 and 1.5-2.5 mmol/kg/day for 8-21 and 22-35 days, respectively. Infants receiving sodium supplements had significantly greater urinary sodium excretion (p < 0.01), retained more sodium (p < 0.01), maintained plasma sodium at normal levels and gained weight at slightly higher rates when compared with those on low sodium. Plasma AVP tended to be higher in group S but did not differ significantly from that in NS group. Urinary AVP excretion, however, either expressed in ng/day or ng/100 ml GFR, was significantly higher in group S, although the age-related increase could not be seen when correction was made for GFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Arginine Vasopressin↗
PubMed1992

[Atrial natriuretic peptides in normal and toxemic pregnancy].

Atrial natriuretic peptide (ANP) is a potent natriuretic and hypotensive substance whose importance in pregnancy has not been fully elucidated. Because abnormalities of sodium and water balance are known to be involved in the pathogenesis of toxemic pregnancy, the authors attempted to evaluate the role of ANP by measuring its plasma concentration in 16 normal and 22 toxemic pregnant women (gestational age 26-40 wks, mean 34.5 +/- 1.2 and 28-40 wks, mean 36.0 +/- 1.0, respectively). The weight gain during pregnancy was significantly higher in the toxemic group (13.9 +/- 1.0 vs 9.1 +/- 1.0 kg, p less than 0.01). Plasma ANP level in the toxemic group (40.65 +/- 6.17 pg/ml) was significantly (p less than 0.05) increased compared to that measured in the normal pregnancy group (22.46 +/- 4.22 pg/ml). There was no statistical correlation between ANP levels and gestational age or weight gain during pregnancy. The results suggest that ANP may play a role in the regulation of impaired water and sodium homeostasis in toxemic pregnancy.

Atrial Natriuretic Factor↗
PubMed1992

Maternal plasma fibronectin and neonatal birth weight.

Similar plasma fibrinoectin levels were found in nonpregnant volunteers and first or third trimester normal pregnant women, while in preeclamptics it was two times higher. The close relationship observed between maternal plasma fibronectin content and corrected fetal birth weight suggests that the state of microcirculation has a profound influence on neonatal birth weight.

Birth Weight↗
PubMed1992

Prolactin and dopamine concentrations in the cerebrospinal fluid during the neonatal period.

UNLABELLED: Prolactin (PRL) has been detected in the cerebrospinal fluid (CSF) in humans and the absolute level appears to reflect the serum PRL concentration. Because PRL is thought to be involved in the regulation of brain water and electrolyte content attempt has been made to determine CSF and plasma PRL and dopamine (DA) concentrations, osmolality, and sodium level in 21 newborn infants undergoing lumbar punction because of apneic spells, fever, or perinatal asphyxia. The mean of gestational age was 36.5 weeks (range: 31-41) and birthweight was 2572 g (range: 1140-3550). The lumbar puncture was performed at the 8.3 postnatal day (range: 1-38). The plasma concentration of PRL was 106.52 +/- 14.43 ng/ml, significantly higher than the CSF PRL level (43.24 +/- 7.39 ng/ml, p < 0.01). This elevated level was observed in all individual cases. DA concentration in the plasma was much higher than the value detected in the CSF (64.75 +/- 13.83 vs 8.64 +/- 0.72 ng/ml, p < 0.01). No difference was observed between the sodium content of the CSF and plasma (138.94 +/- 1.28 vs 138.04 +/- 1.03 mmol/l), however, the osmolality of the plasma tended to be higher than the CSF osmolality (286.7 +/- 3.81 vs 276.76 +/- 2.19 mosm/kg, p < 0.05). In the CSF osmolality, PRL, DA, and sodium concentrations did not show any correlation. IN CONCLUSION: in the CSF PRL probably does not play a primary role in controlling the osmolality and sodium content. PRL in CSF seems to be independent from CSF DA concentration.

Dopamine↗
PubMed1991

The influence of metoclopramide on the composition of human breast milk.

UNLABELLED: The breast milk prolactin (PRL) has been claimed to play a role in the control of electrolyte composition of the milk. Since metoclopramide has been shown to increase milk production in humans, we have made an attempt to investigate the production, the PRL and sodium concentrations in milk with (group I) and without (group II) maternal metoclopramide treatment (5 days, 30 mg/day). Both groups consisted of 11 mothers and their full-term newborn infants. The daily milk production was significantly higher in the treated group (276.4 +/- 36.6 vs 150.9 +/- 25.3 ml/day, p less than 0.01). The PRL measured by RIA was similar in the milk samples of the metoclopramide treated and control groups (80.5 +/- 17.7 vs 90.7 +/- 27.3 ng/ml). The sodium concentration in the milk of mothers taking metoclopramide was 22.1 +/- 1.6 mmol/l and 24.3 +/- 3.2 mmol/l in the control group (p = 0.59). On the 5th postnatal day the plasma PRL of the newborns of mothers treated with metoclopramide does not differ from the values of the control babies (29.8 +/- 2.6 vs 30.7 +/- 2.4 ng/ml) indicating that the amount of metoclopramide transferred into the milk has no apparent influence on the hypothalamo-hypophyseal axis of the neonate. IN CONCLUSION: the maternal metoclopramide treatment augments the milk production without having any effect on the PRL and sodium concentration of human "mature" milk.

Adolescent↗
PubMed1991

Neonatal effects of methyldopa therapy in pregnancy hypertension.

This study has been performed to assess the effect of methyldopa (MD) therapy in pregnancy hypertension on the neonatal adaptation. Infants born to mothers on MD for several weeks prior to delivery and presenting with excessive tremor and irritability were evaluated according to the dose of maternal MD. Pregnancy hypertension and high dose MD was associated with impaired placental perfusion, compromised function of fetoplacental unit and more frequent surgical delivery. Infants of mothers on high (1.25-2.0 g/day) or low (less than 1 g/day) MD had gestational age, head circumference, acid-base balance, Apgar score and blood pressure similar to those born to healthy control mothers. The birth weight of infants of the high MD group, however, were significantly lower than in the low-dose or control groups. MD therapy resulted in a dose-dependent increase in plasma levels of prolactin, thyrotropin and triiodthyronine indicating decreased dopaminergic inhibition of pituitary hormone release. Plasma thyroxine concentration, however, decreased significantly. Cerebrospinal fluid noradrenaline was found to be markedly depressed after maternal MD showing disturbed central nervous system monoamine metabolism. It is suggested that MD administration to mothers presenting with pregnancy hypertension interferes with cerebral monoamine metabolism of the neonate and induces alterations in some endocrine functions under dopaminergic control. The possible role of chronic fetal distress frequently associated with pregnancy hypertension should also be considered.

Adaptation, Physiological↗
PubMed1988

Postnatal course of plasma levels of adrenocortical steroids in premature infants with and without NaCl supplementation.

To assess the adrenocortical response of premature infants to alterations in sodium balance, the postnatal course of plasma progesterone, 11-deoxycorticosterone, corticosteronoe, aldosterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol and cortisone was compared in healthy premature infants kept on low (1-2 mEq/kg per day) or high (3-5 mEq/kg per day) sodium diet. The mean birthweight (1470 g, range: 1210-1670 g vs 1410 g, range: 1130-1750 g) and mean gestational age (30.5 weeks, range: 29-32 weeks vs 30.2 weeks, range: 28-32 weeks) in the low and high sodium groups, respectively, were similar. Simultaneous steroid hormone measurements were made weekly up to the 5th week of life using mechanized Sephadex LH-20 multicolumn chromatography and standardized radioimmunoassays. It was demonstrated that in response to renal salt wasting and negative sodium balance there was a significant rise in plasma aldosterone concentration. The plasma levels of other individual corticosteroids generally declined with advancing age, the initial fall, however, was followed by a transient and insignificant but simultaneous increase in 11-deoxycortisol, cortisol, cortisone and corticosterone in prematures on low a sodium diet. This effect could be prevented by giving NaCl supplement. The NaCl-suppressible increase in adrenocortical activity may be the result of the combined effect of stress or angiotensin 11-induced adrenocorticotropic hormone (ACTH) release and/or prolactin-mediated enhanced adrenal response to ACTH.

17-alpha-Hydroxyprogesterone↗
PubMed1986

Effect of atrial natriuretic peptide on gonadotropin release in superfused rat pituitary cells.

Cardiac atrial muscle cells produce a polypeptide hormone that plays a role in the control of water and electrolyte balance and blood pressure. The circulating form of this hormone is the atrial natriuretic peptide (ANP), which contains 28 amino acids. Various immunohistochemical studies have shown that ANP is present in many areas of the central nervous system, including the median eminence. In our studies, we investigated the effect of ANP in a superfused rat pituitary cell system. When ANP was administered at increasing concentrations (0.01 microM to 1 microM), it caused a significant dose-related stimulation of the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The lowest effective dose of ANP in our system was 0.03 microM. When ANP and LH-releasing hormone were administered together, the response was prolonged and had the characteristics of ANP-stimulated LH and FSH release. In contrast with some previous reports, ANP in high concentration (1 microM) consistently induced a small but significant stimulation of the release of corticotropin. ANP did not influence the basal release of prolactin, growth hormone, and thyrotropin.

Adrenocorticotropic Hormone↗
PubMed1986

Plasma prolactin levels in full-term newborn infants with idiopathic edema: response to furosemide.

In an attempt to explore the possible role of prolactin (PRL) in the control of neonatal electrolyte homeostasis, this study has been carried out to compare plasma electrolyte concentrations, urine volume and urinary electrolyte excretion as well as plasma PRL levels in healthy full-term neonates with idiopathic edema prior to and after furosemide treatment. No differences in plasma sodium and potassium were demonstrated, edematous neonates, however, had less urine volume and sodium excretion than neonates without edema. Plasma PRL proved to be significantly higher in the edematous group (11.0 +/- 1.9 vs. 4.2 +/- 3.1 U/l, p less than 0.01) but it remained unaltered by furosemide challenge (8.5 +/- 1.5 U/l) in spite of the marked elevation of urine flow and sodium excretion. It is concluded that PRL may be involved in the control of the volume and composition of the body fluids in the neonate but further studies are needed to define the effect of changes in body composition on the neonatal PRL secretion.

Diuresis↗
PubMed1985

The effect of dopamine administration on the activity of the renin-angiotensin-aldosterone system in sick preterm infants.

Nine premature infants with birth weight of 1150 to 2500 g and gestational age of 28 to 35 weeks were given dopamine in a dose of 2-4 micrograms/kg/min to treat cardiopulmonary distress. In addition to monitoring of blood gases, blood pressure, acid-base balance, urine flow and urinary sodium excretion, plasma renin activity (PRA) and plasma aldosterone concentration (PA) was also determined prior to and during dopamine therapy. The dopamine-induced increase in urine flow and urinary sodium excretion was associated with a significant increase of PRA from 18.2 +/- 5.1 ng/ml/h to 33.0 +/- 5.6 ng/ml/h (P less than 0.025), while PA and blood pressure remained unaltered by dopamine administration. It is suggested that the angiotensin II-stimulated aldosterone production is overridden by the inhibitory effect of dopamine.

Aldosterone↗
PubMed1985

Late hyponatremia in premature infants: role of aldosterone and arginine vasopressin.

To assess the possible involvement of arginine vasopressin in the pathogenesis of late hyponatremia in preterm infants, serial measurements of sodium balance, fractional sodium excretion, plasma and urine osmolality and sodium concentration, and urinary aldosterone and arginine vasopressin excretion were performed at weekly intervals in nine healthy preterm infants. During the course of late hyponatremia, there was a significant increase in urinary aldosterone and arginine vasopressin excretion, from 0.94 +/- 0.16 to 4.30 +/- 0.76 micrograms/day and from 0.38 +/- 0.08 to 1.19 +/- 0.26 ng/day, respectively, from the first to the fourth to fifth weeks. A significant negative correlation was found between fractional sodium excretion and urinary aldosterone excretion. Aldosterone excretion, however, correlated positively with urinary arginine vasopressin excretion in seven of the nine infants. The parallel increase in urinary aldosterone and arginine vasopressin excretion in salt-losing premature infants may occur in response to the protracted contraction of the extracellular fluid compartment, and may contribute to the restoration of volume in the body fluid compartments and to the development of late hyponatremia.

Aldosterone↗
PubMed1985

Effect of low-dose dopamine infusion on prolactin and thyrotropin secretion in preterm infants with hyaline membrane disease.

The effect of low-dose (2-4 micrograms/kg/min) and long-term (greater than or equal to 46 h) dopamine infusion on serum prolactin and thyrotropin concentrations was investigated in 8 preterm infants with hyaline membrane disease. Dopamine was administered for systemic hypotension and/or for impending renal failure. Serum prolactin decreased from 1,314.5 +/- 422.7 microU/ml to 489.9 +/- 464.1 microU/ml (p less than 0.005), while serum thyrotropin fell from 3.77 +/- 2.27 microU/ml to 1.01 +/- 0.25 microU/ml (p less than 0.025) during dopamine infusion. Our data indicate that exogenous dopamine exerts an inhibitory effect on the secretion of prolactin and thyrotropin even in the sick preterm neonate. The role of prolactin in fetal lung maturation and in regulation of the neonatal tissue water stores is discussed. The results of the present study are also useful in explaining the renal effects of long-term low-dose dopamine infusion in the sick preterm infant.

Dopamine↗
PubMed1985

The influence of NaCl supplementation on the postnatal development of urinary excretion of noradrenaline, dopamine, and serotonin in premature infants.

The present study was designed to investigate the role of noradrenaline (NA), dopamine (DA), and serotonin (5-HT) in the adaptation of premature infants to alterations of sodium balance. Urinary excretion of NA, DA, and 5-HT was measured spectrofluorimetrically in a group of low birth weight premature infants with (group S) and without (group NS) NaCl supplementation. Group NS consisted of 10 infants with a birth weight of 1200-1750 g (mean, 1493 g) and gestational age of 28-31 wk (mean, 30.1 wk). Group S included 10 infants with mean birth weight of 1414 g (range, 1150-1600 g) and mean gestational age of 30.5 wk (range, 27-32 wk). Measurements were made on the 7th day and weekly thereafter until the 5th wk of life. NaCl supplementation was given in a dose of 3-5 and 1.5-2.5 mEq/kg/day for 8-21 and 22-35 days, respectively. In group NS, mean urinary excretion of NA and DA increased from 8.6 +/- 1.5 and 15.8 +/- 2.4 micrograms/day to maximum values of 21.4 +/- 5.5 (p less than 0.05) and 33.4 +/- 6.0 micrograms/day (p less than 0.01) in weeks 2-3, respectively. 5-HT excretion averaged about 60 micrograms/day and showed no consistent change during the course of the study. NaCl supplementation prevented the rise of NA and DA excretion above the initial baseline values. The postnatal course of 5-HT excretion, however, remained unaffected by NaCl supplementation. Urinary excretion of NA in weeks 2-3 (p less than 0.05) and DA in weeks 2-4 (p less than 0.05) were significantly lower in group NS.

Dopamine↗
PubMed1985

The effect of metoclopramide administration on electrolyte status and activity of renin-angiotensin-aldosterone system in premature infants.

The present study has been carried out to define whether endogenous dopamine contributes to the regulation of renal sodium handling and the function of the renin-angiotensin-aldosterone system in low birth weight premature infants. Twelve premature infants with mean birth weight of 1420 g and mean gestational age of 29.2 wk were given metoclopramide (MTC) in a dose of 0.1 mg/kg/day to treat delayed gastric emptying, regurgitation, and abdominal distension at the age of 17-23 days. Infants were kept on either a low (2-3 mEq/kg/day) or high (4-7 mEq/kg/day) sodium diet to modulate activity of RAAS. Prior to and after a 3-day period of MTC administration, blood samples were taken, and in six male infants 24-h urine collections were made to determine plasma and urine electrolytes, plasma renin activity, plasma aldosterone concentration, and urinary aldosterone excretion. We demonstrated that plasma sodium and potassium concentrations and plasma renin activity were not altered by MTC. On the other hand, in response to MTC, there was a significant increase in urinary sodium excretion (1.8 +/- 0.3 versus 2.3 +/- 0.3 mEq/kg/day) and a decrease in potassium excretion (1.2 +/- 0.2 versus 0.8 +/- 0.1 mEq/kg/day); plasma aldosterone concentration and urinary aldosterone excretion decreased significantly from initial values of 2101 +/- 274 pg/ml and 2.91 +/- 0.52 micrograms/day to 1500 +/- 207 pg/ml (p less than 0.01) and 2.21 +/- 0.43 micrograms/day (p less than 0.01), respectively, after MTC. These alterations were independent of the pretreatment hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗