Biomedical subjects

C G Hatjis

Publications and source records attributed to C G Hatjis.

At least 37 records · Page 2Linked to original sources

PubMed1988

Atrial natriuretic peptide receptors in sheep cotyledons.

Effects dependent on atrial natriuretic peptide are mediated through specific atrial natriuretic peptide plasma membrane receptors. We previously demonstrated the presence of specific atrial natriuretic peptide receptors in human placental membranes. We asked whether atrial natriuretic peptide specific receptors are present in sheep cotyledons. Sheep cotyledons were obtained from pregnant ewes at 125 to 142 days' gestation. Each cotyledon was separated into two components, the outer layer (maternal capsule) and the spongy inner layer (fetal component). A microsomal plasma membrane fraction was prepared from each layer. Atrial natriuretic peptide receptors were detected by in vitro radioligand techniques with 125I-alpha-human atrial natriuretic peptide. In sheep cotyledons there are two sets of atrial natriuretic peptide receptors that show either high-affinity/low-capacity or low-affinity/high-capacity binding characteristics. Moreover, membranes from the inner layer (fetal component) appear to have a lower concentration of high-affinity atrial natriuretic peptide binding sites than those from the maternal capsule.

Animals↗

PubMed1988

Atrial natriuretic peptide receptors in normal human placentas.

We studied whether plasma membranes from normal human placentas contain receptors for atrial natriuretic peptide. We identified specific, high-affinity, low-capacity atrial natriuretic peptide binding sites in the nonbrush border, microsomal fraction presumed to originate from cellular membranes near the fetal circulation. In contrast, no atrial natriuretic peptide binding sites could be identified in the brush border; the latter is exposed to maternal blood in the intervillous space. The presence of atrial natriuretic peptide binding sites in human placentas suggests that atrial natriuretic peptide may be involved in fluid and electrolyte homeostasis in human gestation.

Alkaline Phosphatase↗

PubMed1988

Systemic tocolysis for premature labor is associated with an increased incidence of pulmonary edema in the presence of maternal infection.

Our hypothesis is that systemic tocolysis of patients in premature labor is associated with a higher incidence of pulmonary edema in the presence of maternal infection. Over a 64-month period, medical records of all patients with a diagnosis at discharge of pulmonary edema or congestive heart failure were reviewed. There were 27 cases of pulmonary edema, 16 of which (59.3%) were associated with treatment of preterm labor. The incidence of pulmonary edema in patients receiving systemic tocolysis for treatment of preterm labor was significantly higher than that in our general obstetric population (3.04% versus 0.05%). Of the 527 patients receiving tocolysis, there was evidence of maternal infection in 52. The incidence of pulmonary edema was higher in the presence of maternal infection than in its absence (11/52 or 21% versus 5/475 or 1%, p = 0.0000). We conclude that there is a very strong association between the development of pulmonary edema and the presence of maternal infection in patients being treated for premature labor with systemic tocolysis.

Female↗

PubMed1988

Regulation of guinea pig myometrial beta-adrenoreceptors by guanosine triphosphate and magnesium ion.

The effects of guanosine triphosphate (GTP) and magnesium on the interaction of 1-isoproterenol with beta-adrenoreceptors were studied in myometrial membranes from nonpregnant and late-pregnant (0.9 gestation, term 65 days) guinea pigs. The affinity of the beta-adrenoreceptor for 1-isoproterenol, as measured by inhibition of (-)125I-cyanopindolol binding, was increased by 10 mM MgCl2. The addition of 250 microM GTP reversed this process. In the presence of MgCl2, the competition curves could be resolved into two affinity states of the beta-adrenoreceptor, high and low, respectively. The ratio of the dissociation constant of the high-affinity state to that of the low-affinity state was significantly higher in late-pregnant than in the nonpregnant animals. In the presence of GTP, there was only one (low-affinity) state of the receptor detectable. In both groups of animals, the interaction between beta-adrenoreceptor agonists and myometrial beta-adrenoreceptors was positively modulated by MgCl2. This process was reversed by GTP. However, there appeared to be a differential regulation of the ability of the myometrial beta-adrenoreceptor to form a high-affinity state, depending on the reproductive state of the animal.

Animals↗

PubMed1988

Up-regulation of guinea pig myometrial beta-adrenoreceptors by systemic estradiol and progesterone.

The effects of systemic administration of 17 beta-estradiol (E2) and progesterone (P) on the concentration and affinity of myometrial beta-adrenoreceptors were studied in non-pregnant, previously oophorectomized guinea pigs receiving a continuous infusion of E2, P, a combination of the two hormones, or placebo for 7 days. Myometrial beta-adrenoreceptors were characterized by using (-)-[125I-cyanopindolol as the specific beta-adrenoreceptor ligand. Compared to that in the control group, E2 administration resulted in a 7-fold increase in the density of myometrial beta-adrenoreceptors. Administration of P alone resulted in a significant increase in both beta-adrenergic receptor concentration and the receptor dissociation constant (Kd). Finally, a combination of E2 and P treatment did not result in any synergistic or additive effect for the beta-adrenergic receptors, while the Kd was twice that of the control or E2-treated animals. We conclude that systemic administration of these sex steroid hormones, directly or indirectly, modulates myometrial beta-adrenergic receptor concentrations and their ligand affinity.

Animals↗

PubMed1987

Myocardial adenylate cyclase activity in ritodrine-treated pregnant rabbits.

To determine whether prolonged exposure to ritodrine results in down-regulation of myocardial adenylate cyclase activity during pregnancy, New Zealand White rabbits with time-dated pregnancies were randomly assigned to a sham-operated control group and to a ritodrine-treated group. Starting at 22 days' gestation (term 31 days), animals received either intravenous ritodrine intermittently or the equivalent volume of vehicle for 3 days. Adenylate cyclase activity was determined in a plasma membrane fraction obtained from ventricular tissue. There was no difference in the basal activity or the basal and guanosine triphosphate activity between the two groups. L-Isoproterenol-dependent stimulation required the presence of guanosine triphosphate. Both maximal and 50% enzymatic stimulation were equivalent in both groups. Furthermore, sodium fluoride-dependent stimulation was similar in both groups. Finally, adenylate cyclase activity in the presence of forskolin and manganese chloride was similar in both groups. From the above, we conclude that intermittent systemic infusions of ritodrine to pregnant rabbits did not result in down-regulation of myocardial adenylate cyclase activity.

Adenylyl Cyclases↗

PubMed1987

C-reactive protein: a limited test for managing patients with preterm labor or preterm rupture of membranes?

C-reactive protein has been used to identify patients at high risk for infectious morbidity with preterm labor or preterm rupture of membranes. In this article we report on 104 patients with preterm labor symptoms (n = 45) or preterm rupture of the membranes (n = 59) and serial evaluations of C-reactive protein measured by latex agglutination and laser nephelometry. The simple, inexpensive latex method appears comparable to the laser method in predicting infectious morbidity and can be used clinically. Elevated C-reactive protein values before delivery predict infectious morbidity in only 8% to 29% of patients, and up to 18% of patients with serious infections may be misdiagnosed as having normal C-reactive protein values before delivery.

C-Reactive Protein↗

PubMed1987

Vasopressin-resistant diabetes insipidus, liver dysfunction, hyperuricemia and decreased renal function. A case report.

A case of transient nephrogenic diabetes insipidus occurred in late pregnancy, the first associated with biopsy-proven hepatitis. Five previously reported cases occurred in pregnancy. All six patients demonstrated similar but transient signs, symptoms and laboratory abnormalities suggesting a syndrome peculiar to pregnancy. The characteristics of this syndrome are elevated liver function studies, decreased renal function, hyperuricemia and transient vasopressin-resistant diabetes insipidus.

Adult↗

PubMed1987

Anterior sacral meningocele in pregnancy.

Anterior sacral meningocele is a rare abnormality. Only 14 cases of it have been reported in association with pregnancy. Of those 14 patients, three died as a result of rupture of the meningocele during labor and postpartum. A new case is presented; the clinical presentation, the diagnosis, and treatment are discussed. The obstetric management of the case is discussed and a plan for management is suggested.

Adult↗

PubMed1987

Efficacy of combined administration of magnesium sulfate and ritodrine in the treatment of premature labor.

Seventy-four patients in preterm labor at 20-35 weeks' gestation were randomly assigned to receive ritodrine (N = 36) or ritodrine plus magnesium sulfate treatment (N = 38) for tocolysis. Ten did not complete therapy and were excluded from analysis. Nineteen of 32 patients (59%) in the ritodrine plus magnesium sulfate group were successfully treated, compared with only 11 of 32 patients (34%) in the ritodrine-only group (P less than .05). Of the 21 patients who failed to respond to the initial ritodrine treatment, 16 received intravenous magnesium sulfate supplemental therapy; 75% of this group were treated successfully. The frequency of adverse maternal and fetal side effects did not differ between the treatment groups. In the combined group compared with the ritodrine group, the dose requirements for ritodrine therapy as well as the total duration of treatment for both ritodrine and magnesium sulfate were reduced significantly. We conclude that concurrent administration of ritodrine and magnesium sulfate is more efficacious than ritodrine alone and does not appear to increase the frequency of adverse side effects.

Drug Therapy, Combination↗

PubMed1986

Forskolin: unique diterpene activator of adenylate cyclase in pregnant and nonpregnant guinea pig myometrial membranes.

In guinea pig myometrium, beta-adrenergic receptors are functionally coupled to adenylate cyclase. beta-Adrenergic receptor agonists in the presence of guanosine triphosphate stimulate adenylate cyclase activity, thus increasing 3'5'-cyclic adenosine monophosphate synthesis and promoting myometrial relaxation. In pregnant animals close to term (65 days), beta-adrenergic receptor density as well as basal and (-)isoproterenol-dependent (in the presence of guanosine triphosphate) adenylate cyclase activity is significantly higher than that in nonpregnant animals or those in early pregnancy. Since this system appears to be made up of at least three components (beta-adrenergic receptor, guanosine triphosphate-binding protein, and a catalytic component), these observations on total adenylate cyclase activity may reflect alterations in one or more of these components. To answer the question whether the catalytic unit of this system can be directly assayed and whether its activity is influenced by pregnancy, we have performed in vitro experiments to measure the enzymatic activity of the catalytic component of the beta-adrenergic receptor-adenylate cyclase complex in guinea pig myometrial membranes. We have used two compounds that stimulate the catalytic component: forskolin and manganese chloride. Forskolin, regardless of the presence or absence of guanosine triphosphate, is the most potent stimulator of adenylate cyclase activity in myometrial membranes from nonpregnant and pregnant animals; manganese chloride is a less potent activator. The degree of adenylate cyclase stimulation by forskolin tends to be higher in uteri from pregnant (greater than or equal to 0.5 gestation) than from nonpregnant or postpartum animals. It was concluded: that adenylate cyclase stimulation by forskolin does not depend on the presence of beta-adrenergic receptor agonists or guanosine triphosphate and that with advancing gestation there might be a qualitative or quantitative change with regard to the interaction between forskolin and the presumed catalytic component of the beta-adrenergic receptor-adenylate cyclase complex.

Adenylyl Cyclases↗

PubMed1986

Forskolin-stimulated adenylate cyclase activity in fetal and adult rabbit myocardial membranes.

It has previously been reported that there is an increase in the concentration of myocardial beta-adrenergic receptors as well as an increase in the sensitivity of adenylate cyclase stimulation by L-isoproterenol in fetal rabbit myocardial membranes from 21 to 31 days' gestation. To investigate whether a change in the catalytic component of the beta-adrenergic receptor-adenylate cyclase complex is responsible for the observed increase in adenylate cyclase activity, I have measured the latter in the presence of forskolin and manganese chloride, compounds that can directly stimulate the catalytic component. Myocardial membranes were obtained from fetal rabbits at 21, 28, and 31 days' gestation and from pregnant adult animals. There was an increase in basal adenylate cyclase activity from the fetal to the adult stage. The percent of maximal stimulation by L-isoproterenol in fetuses from 21 through 28 to 31 days' gestation and in the adult animal. However, although forskolin was the most potent stimulator of adenylate cyclase, the degree of stimulation was equivalent in all groups tested. Similar results were obtained with manganese chloride. We conclude that the catalytic component of the beta-adrenergic receptor-adenylate cyclase complex in myocardial membranes is stimulated to an equivalent degree at all gestational ages in fetal and adult rabbits and shows no maturational changes.

Adenylyl Cyclases↗

PubMed1986

Sinusoidal fetal heart rate pattern associated with butorphanol administration.

One hundred nineteen fetal heart rate monitor tracings from term-pregnant patients in labor were reviewed by two independent observers to test the hypothesis that Stadol administration to mothers does not result in sinusoidal fetal heart rate pattern. There was agreement with regard to the interpretation of the tracings in 106 instances. Fifty-one patients received intravenous Stadol for narcotic analgesia. Seventy-five percent of these patients demonstrated a transient sinusoidal fetal heart rate pattern after Stadol administration. In a small number of patients, this pattern recurred either with or without additional Stadol treatment. In contrast, patients who did not receive Stadol therapy (N = 55) demonstrated a significantly lower incidence of sinusoidal fetal heart rate pattern (13%), the duration of which was significantly shorter than that seen in the former group. From these we conclude that Stadol therapy during labor is strongly associated with the appearance of sinusoidal fetal heart rate pattern. There were no short-term maternal or neonatal adverse sequelae. In the absence of other fetal heart rate signs suggestive of fetal distress, the presence of sinusoidal fetal heart rate pattern after Stadol administration does not indicate fetal hypoxia.

Anesthesia, Obstetrical↗

PubMed1985

Effect of treatment with sodium valproate on plasma adrenocorticotropic hormone and cortisol concentrations in pregnancy.

To investigate whether treatment with valproic acid in pregnancy decreases adrenocorticotropic hormone and cortisol secretion, we measured their concentrations in maternal and umbilical cord blood from a patient receiving valproic acid. We found them to be normal. Valproic acid may not decrease adrenocorticotropic hormone/cortisol levels in pregnant patients or their fetuses.

Adrenocorticotropic Hormone↗

PubMed1985

beta-Adrenergic-receptor and adenylate cyclase properties in pregnant and nonpregnant guinea pig myometrium.

Stimulation of myometrial beta-adrenergic receptors by agonists results in myometrial relaxation through adenylate cyclase-dependent mechanisms. Their activity is modulated by local or systemic estrogen-progesterone milieu. During pregnancy, guinea pigs demonstrate an ovarioplacental shift for progesterone production at less than or equal to 0.35 gestation and a gradual increase in estrogen levels. To investigate whether these changes affect myometrial beta-adrenergic-receptor and adenylate cyclase properties, we directly characterized beta-adrenergic receptors and adenylate cyclase in myometrial plasma membranes from time-dated pregnant (term 65 days), postpartum, and nonpregnant virgin guinea pigs by well-established in vitro methods. In all animals, there appeared to be a high-affinity, low-capacity, single class of binding sites with pharmacologic specificities consistent with the beta 2-adrenergic-receptor subtype. The dissociation constants of these beta-adrenergic receptors were significantly decreased in pregnant animals at approximately greater than or equal to 0.80 gestation when compared to pregnant animals at 0.35 to 0.40 gestation, nonpregnant animals, and postpartum animals. Moreover, the total number of beta-adrenergic receptors was significantly higher at greater than or equal to 0.80 gestation than in the other groups. Basal adenylate cyclase activity increased in animals from 0.35 to greater than or equal to 0.8 gestation and was higher than that of postpartum animals and nonpregnant animals. The degree of adenylate cyclase stimulation by (-)isoproterenol was higher at term than at an earlier point in gestation or in nonpregnant and postpartum animals. These results indicate that, with advancing gestation in pregnant animals, there is an up-regulation of beta-adrenergic-receptor and adenylate cyclase function.

Adenylyl Cyclases↗

PubMed1985

Adenylate cyclase activity in fetal rabbit myocardium.

Adenylate cyclase activity [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] was determined in vitro in fetal rabbit myocardial membranes from individual fetal pups at 21 to 31 days gestation (term, 31 days). Basal and NaF-stimulated adenylate cyclase activities did not change during 21-31 days gestation. Significant stimulation of the enzyme by l-isoproterenol was observed only in the presence of guanosine triphosphate (100 microM). Under these conditions, maximal adenylate cyclase stimulation by l-isoproterenol (100 microM) was significantly higher at 25-31 than at 21 days gestation. Moreover, EC50 (Kact) for l-isoproterenol at 25-31 days was significantly lower than at 21 days gestation. We conclude that, in fetal rabbit myocardial membranes, there is an increase in the sensitivity of adenylate cyclase stimulation by l-isoproterenol from 21 to 25-31 days gestation.

Adenylyl Cyclases↗

PubMed1985

Nonimmunologic fetal hydrops associated with hyperreactio luteinalis.

A case of nonimmunologic fetal hydrops associated with maternal bilateral theca lutein cysts (hyperreactio luteinalis) is presented. It is proposed that the theca lutein cysts were caused by elevated human chorionic gonadotropin (hCG) production from the hydropic placenta. These cysts appeared to regress after the patient's delivery, while beta-hCG levels declined.

Abnormalities, Multiple↗

PubMed1985

Total parenteral nutrition in pregnancy.

Total parenteral nutrition has been used infrequently during pregnancy. Because of the special nutritional needs and hormonal environment of the maternal-fetal unit, there is uncertainty as to the optimal composition and quantity of total parenteral nutrition therapy. In this report two important questions are examined: whether or not a protein replacement commonly used in total parenteral nutrition provides adequate levels of essential amino acids to fetus and mother, and whether or not the daily use of fat emulsion as part of total parenteral nutrition is associated with unwanted side effects. The authors' data suggest that certain adjustments have to be made in the quantity and composition of total parenteral nutrition constituents to provide the necessary nutritional requirements for metabolic and anabolic needs without increasing the overall risk for complications.

Adult↗