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Biomedical subjects

P Samuels

Publications and source records attributed to P Samuels.

At least 37 records · Page 2Linked to original sources
PubMed1994

The differential effects of body fat distribution on insulin and glucose metabolism during pregnancy.

OBJECTIVE: Our purpose was to investigate whether maternal obesity, or more specifically body fat distribution, is associated with alterations in carbohydrate metabolism during pregnancy. STUDY DESIGN: A longitudinal study of oral glucose tolerance tests, insulin, C peptide, and glucagon levels during each trimester and post partum was undertaken in nine lean and 14 obese women. Obese women were divided into lower body obese (n = 6, waist/hip ratio < 0.9) and upper body obese (n = 8, waist/hip ratio > or = 0.9). RESULTS: Fasting blood glucose levels declined with advancing gestation only in lean subjects. Upper body obese women demonstrated maximal glucose response and insulin area under the curve by the second trimester, whereas lean and lower body obese women did not until the third trimester. Insulin areas were significantly elevated in upper body obese compared with lower body obese women (second trimester, p < 0.01; third trimester, p < 0.03; post partum p < 0.05). In contrast, C peptide levels were similar in obese subgroups and were significantly elevated only when compared with those of lean women. C peptide/insulin molar ratios were lower in upper body obese women during the second trimester (4.3 +/- 0.8) and third trimester (4.2 +/- 0.7) compared with lean (6.5 +/- 1.3, 6.7 +/- 0.5) and lower body obese women (7.9 +/- 1.4, 6.5 +/- 1.4) (p < 0.01). A significant relationship between waist/hip ratio and glucose level (r = 0.70, p < 0.004) and insulin areas (r = 0.76, p < 0.001) was present in late pregnancy in obese subjects. CONCLUSIONS: Relative hyperinsulinemia and earlier maximal glucose response in upper body obese women suggests that body fat distribution may explain the metabolic heterogeneity present in obese women during pregnancy. Body fat topography may serve as a potential marker for the early development of carbohydrate intolerance during pregnancy.

Adipose Tissue↗
PubMed1993

Detection of antitrophoblast antibodies in the sera of patients with anticardiolipin antibodies and fetal loss.

Women with anticardiolipin antibodies (ACLA) are at increased risk for fetal loss. One potential explanation for this outcome is that sera from these individuals contain antibodies reactive with trophoblast cells, which are involved in the establishment of the uteroplacental vasculature and maintenance of placental blood fluidity. To examine this hypothesis, we compared the incidence of trophoblast-reactive antibodies in 27 patients with ACLA and a history of fetal loss with that in 29 normal pregnant women. Sera from 20 patients, but only one control, contained trophoblast-reactive antibodies (P < .001). These antibodies were not directed against major histocompatibility class I antigens, and reacted with both term and first-trimester trophoblast cells. In most cases, sera from which ACLA were adsorbed by cardiolipin-containing liposomes maintained reactivity against cells. In addition, patient Ig fractions immunoprecipitated an approximately 62-kD protein from the trophoblast cell surface, stimulated the release of arachidonic acid and thromboxane A2 by trophoblasts, and inhibited the binding of prourokinase to trophoblast urokinase receptors. These observations show that sera from women with ACLA and a history of fetal loss contain antitrophoblast antibodies. These antibodies may be serologically distinct from ACLA, and may contribute to the pathogenesis of fetal demise.

Abortion, Spontaneous↗
PubMed1993

Plasma concentration of endothelin-1 in women with cocaine-associated pregnancy complications.

OBJECTIVE: The purpose of this study was to determine if the plasma concentration of endothelin-1 is elevated in pregnant women abusing cocaine and to determine how these levels differ from those in patients with preeclampsia and in women with uncomplicated pregnancies. STUDY DESIGN: Plasma endothelin-1 levels were measured in 30 women with acute cocaine intoxication, 32 women with preeclampsia, 14 pregnant women with chronic hypertension, 26 women with uncomplicated pregnancies, and 16 nonpregnant individuals. Serial samples after delivery were obtained in 12 women with preeclampsia, 10 with cocaine abuse, 4 with chronic hypertension, and 7 with uncomplicated pregnancies. RESULTS: The mean endothelin-1 concentration in those with cocaine abuse was 18.2 +/- 8.1 pg/ml (95% confidence interval 15.2 to 21.2). This was similar to that in women with preeclampsia (21.1 +/- 5.9 pg/ml, 95% confidence interval 19 to 23.3) (p = 0.2) but significantly different from that in women with chronic hypertension (11.5 +/- 3.6 pg/ml, 95% confidence interval 9.4 to 13.6) (p < 0.001) and women with uncomplicated pregnancies (6.7 +/- 3.9 pg/ml, 95% confidence interval 5.1 to 8.2) (p < 0.001). CONCLUSIONS: Endothelin-1 levels in women abusing cocaine are comparable to those in women with preeclampsia and are significantly higher than those in gravid women with chronic hypertension and women with uncomplicated pregnancies. Elevated levels of endothelin-1 may contribute to some of the pregnancy-related complications in women abusing cocaine.

Adult↗
PubMed1993

Umbilical artery and ductal blood flow velocities in patients treated with aspirin and prednisone for presence of anticardiolipin antibody.

Fifteen patients with previous pregnancy losses and positive plasma anticardiolipin antibody (ACA) were treated with prednisone (15 mg/day) and aspirin (80 mg/day). We measured Doppler velocimetries of umbilical artery and ductus arteriosus at intervals of 2 to 3 weeks starting from 20 weeks of gestation until delivery. Umbilical artery systolic/diastolic ratios (S/D) and maximum systolic velocities of ductus arteriosus did not differ from normal values. There were no poor outcomes in the treated group. ACA positive patients with previous poor pregnancy outcome when treated with prednisone and aspirin have umbilical artery and ductal flow velocities similar to those of the normal population.

Abortion, Habitual↗
PubMed1992

Maternal glucose intolerance and the subcutaneous terbutaline pump.

OBJECTIVE: Our hypothesis was that use of the subcutaneous terbutaline pump does not affect maternal glucose tolerance. STUDY DESIGN: With the 1-hour glucose tolerance test, we examined the incidence of glucose intolerance in 37 patients using the pump compared with that of 54 patients receiving oral terbutaline and 634 control subjects without risk factors for gestational diabetes. The frequency of gestational diabetes and the need for insulin to maintain glycemic control were subjected to chi 2 analysis. RESULTS: The incidence of gestational diabetes was 6% in the control subjects, 5% in patients using the pump (p = 0.8), and 11% in those on the oral therapy regimen (p = 0.4). A total of 8% of controls who had gestational diabetes required both insulin and diet, compared with 100% using the pump (p less than 0.01) and 50% on the oral terbutaline regimen (p = 0.03). CONCLUSION: The incidence of gestational diabetes is not increased in patients receiving terbutaline via the subcutaneous pump. The use of terbutaline by any route significantly increases the need for insulin to achieve glycemic control.

Administration, Oral↗
PubMed1992

Evaluation of maternal fluid dynamics during tocolytic therapy with ritodrine hydrochloride and magnesium sulfate.

OBJECTIVE: The purpose of the study was to observe and compare the effects of ritodrine hydrochloride and magnesium sulfate on maternal fluid dynamics. STUDY DESIGN: Fourteen women in preterm labor were prospectively studied during tocolytic therapy with either ritodrine hydrochloride or magnesium sulfate. The cardiovascular and renal effects of a pretreatment crystalloid infusion were compared with those observed during tocolytic therapy. Profile analysis and repeated measures of variance were used to analyze the data. RESULTS: Ritodrine hydrochloride was associated with decreased colloid osmotic pressure, hematocrit, and serum proteins and increased maternal and fetal heart rates. Arginine vasopressin levels increased during the first 2 hours of therapy, then returned to baseline. Sodium excretion was reduced and there was marked fluid retention. Intravenous magnesium sulfate also resulted in a reduction of colloid osmotic pressure, but hematocrit, serum protein concentration, arginine vasopressin, maternal and fetal heart rates, and mean arterial pressure were minimally affected. Sodium excretion increased to a maximum at 6 to 8 hours of treatment, then returned to baseline. A positive fluid balance was also noted in magnesium sulfate-treated patients but to a lesser degree than with ritodrine. CONCLUSIONS: Sodium retention appears to be the primary cause of plasma volume expansion in ritodrine-treated patients, whereas volume expansion during magnesium sulfate therapy is probably related to intravenous overhydration. In the absence of risk factors for pulmonary capillary membrane injury, available evidence supports volume overload as the principal mechanism for pulmonary edema during tocolytic therapy.

Arginine Vasopressin↗
PubMed1992

Randomized, double-blind study of cefotetan and cefoxitin in post-cesarean section endometritis.

OBJECTIVE: The hypothesis of the study is that cefotetan and cefoxitin will be equally efficacious and safe in the treatment of post-cesarean section endometritis. STUDY DESIGN: In a double-blind, randomized manner 140 patients with post-cesarean section endometritis were treated with cefotetan, 2 gm intravenously every 12 hours, or cefoxitin, 2 gm intravenously every 6 hours. They were followed prospectively for clinical response and side effects. Cure rates between the two groups were compared with the chi 2 test. RESULTS: The cure rates were 83% for cefotetan and 79% for cefoxitin (p = 0.56). No patient required a change in therapy due to adverse effects, and no abnormal bleeding occurred. CONCLUSION: In this study cefotetan and cefoxitin appeared equally effective in treating endometritis with no difference in side effects or complications.

Adult↗
PubMed1992

The utility of the TDx test in the assessment of fetal lung maturity.

Accurate assessment of fetal lung maturity is essential in the management of high-risk obstetric patients. New rapid techniques have been developed to supplement time-consuming chromatographic methods. We compared one of these newer methods, the TDx-FLM, to the standard tests for fetal pulmonary maturity. There was an excellent correlation between the TDx and the lecithin-sphingomyelin ratio (r = 0.78). Although a TDx value of 70 or greater is considered mature, we found a value of 50 or greater predictive of fetal lung maturity in 100% of cases, and have chosen to redefine a mature value as 50 or greater in our institution. This value has greatly enhanced the clinical applicability of the test, allowing use of a large number of specimens from the previously poorly understood and often disregarded borderline category.

Amniotic Fluid↗
PubMed1992

Prenatal detection and management of quadruple nuchal cord. A case report.

As imaging techniques improve, nuchal cords are often being identified prior to labor. Nuchal cords are encountered in up to 25% of deliveries and are usually not clinically significant. They may, however, have devastating results. Nuchal cords may be associated with abnormal fetal activity and testing, but there is often no clinical warning of a nuchal cord during pregnancy, labor or delivery. We report a case of a quadruple nuchal cord discovered after the mother complained of decreased fetal movement. The clinical course of this patient highlights many of the difficulties encountered in the management of antenatally diagnosed nuchal cords, particularly in the preterm fetus.

Acidosis↗
PubMed1992

Pregnancies complicated by liver disease and liver dysfunction.

Although liver dysfunction is infrequently seen in pregnancy, it can result in severe maternal and fetal compromise. An unrecognized case of acute fatty liver may result in both maternal and fetal death. Failure to screen for hepatitis B can result in a newborn who will be a hepatitis carrier for life. Because of such consequences, the obstetrician must remain vigilant for signs of liver dysfunction and must understand the pathophysiology of these disorders.

Cholestasis, Intrahepatic↗
PubMed1991

Detection of endothelial cell-reactive immunoglobulin in patients with anti-phospholipid antibodies.

Individuals with anti-phospholipid antibodies are at increased risk for the development of thrombosis and fetal loss. The pathogenesis of these syndromes is unknown, but may involve antibody-mediated alterations in endothelial cell coagulant activity. To address this possibility, we determined the incidence of endothelial cell-reactive antibodies in 76 patients whose plasma contained anti-phospholipid antibodies, but who had no clinically-evident immune disorder. Plasma from 47 patients deposited significantly more immunoglobulin on cultured endothelial cells than control plasma. Positive tests were more frequent in patients with a history of thrombosis than in those without (17/19 v 23/48; P = 0.004). However, we observed no correlation between immunoglobulin deposition on cardiolipin and endothelial cells by individual plasmas. Furthermore, endothelial cell reactivity was not diminished by adsorption of anti-cardiolipin antibodies from patient sera using liposomes. Immunoglobulin fractions prepared from 5/6 patient sera immunoprecipitated a approximately 70 kDa endothelial cell surface protein; 4/5 of these fractions also induced the release of von Willebrand factor from endothelial cells. These results demonstrate that plasma from many patients with anti-phospholipid antibodies, but no clinically-evident autoimmune disease, also contains endothelial cell-reactive antibodies. Detection of such antibodies might help identify individuals in this patient population at greatest risk for thrombosis.

Antibodies↗
PubMed1991

Gentamicin pharmacokinetics in postpartum women with endomyometritis.

The pharmacokinetics of gentamicin in postpartum women with endomyometritis were characterized and models for predicting patient pharmacokinetic parameters were developed using multiple regression analysis. Fifty-one women 13-34 years of age received gentamicin in combination with either ampicillin or clindamycin to treat endomyometritis. Forty-three women delivered by cesarean section and 8 women had vaginal deliveries. Gentamicin serum concentrations were determined at steady-state to compute the elimination rate constant (Kc), half-life (t1/2), apparent volume of distribution (Vd), and total body clearance (Cl). Gentamicin dosages were individualized using a one-compartment intermittent infusion model to achieve steady-state peak and trough concentrations of 6.5 and less than 2 micrograms/mL, respectively. The mean gentamicin t1/2 was 2.8 +/- 0.9 h; the mean apparent Vd was 21 +/- 8 L; and the mean total body Cl was 89.5 +/- 31.7 mL/min. Multiple regression analysis revealed that total body weight (TBW) was the best predictor for the apparent Vd, described by the equation Vd = 0.146 TBW + 8.153 (r = 0.56, p = 0.00005). Total body weight and creatinine clearance (Clcr) were included as predictors for total body Cl, described by the equation Cl = 0.264 TBW + 0.337 Clcr + 3.416 (r = 0.68, p = 0.00005). Age and serum creatinine (SCr) were included in the models for the Ke, described by the equation Ke = -3.770 x 10(-3) age -0.115 SCr + 0.449 (r = 0.42, p less than 0.004). Additional patient factors need to be identified to explain the variance in these pharmacokinetic parameters.

Adolescent↗
PubMed1991

Advances in anesthesia and pharmacology in the puerperium.

The past year has provided us with some interesting studies concerning pharmacology and anesthesia during the puerperium. I review the prevalence of various anesthetic techniques, as well as the use of different aspiration prophylaxis regimens. I also look at innovations in the administration of epidural and subarachnoid anesthetics, including use of the Sprotte needle to prevent postoperative headache. A small study shows that vitamin administration to premature neonates may prevent periventricular hemorrhage. Furthermore, predelivery injections of glucocortoid may protect against bronchopulmonary dysplasia. I also review painstaking studies that help to better understand thyroid stimulation and regulation during pregnancy. I hope this paper helps the busy obstetrician understand some of the highlights of this year's new literature on obstetric anesthesia and pharmacology.

Analgesia, Obstetrical↗
PubMed1991

Transvaginal cerclage under ultrasound guidance in cases of severe cervical hypoplasia.

Transabdominal cervical cerclage has been advocated for patients with cervical incompetence whose cervix is flush against the vaginal wall. Although several series of successful transabdominal cerclage have been reported, the morbidity of this technique precludes its routine use. We describe five pregnancies in four patients with extreme cervical hypoplasia who underwent successful prophylactic transvaginal cerclage placement at 12-13 weeks' gestation. All patients had a history of intrauterine diethylstilbestrol exposure, and three patients had also undergone cervical conization. In each case, using continuous transabdominal ultrasound guidance, the supravaginal cervix was dissected and two nonabsorbable sutures were placed through the cervix at right angles at the level of the anatomical internal os. There were no perioperative complications, and except for one patient who developed severe preeclampsia at 33 weeks, all patients delivered at term. We believe that the use of ultrasound in cases of severe cervical hypoplasia allows safe transvaginal cerclage placement, obviating the need for abdominal cerclage.

Abnormalities, Drug-Induced↗