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Biomedical subjects

R W Olson

Publications and source records attributed to R W Olson.

At least 19 recordsLinked to original sources
PubMed1989

Phosphatidylglycerol, lecithin/sphingomyelin ratio and respiratory distress syndrome in diabetic and non-diabetic pregnancies.

Samples of amniotic fluid from 514 non-diabetic and 69 diabetic patients were analyzed for phospholipid content. Results were correlated with incidence of respiratory distress syndrome (RDS) in the neonate. The incidence of RDS was 4.5% among diabetics and 5.3% among non-diabetics. In the presence of phosphatidylglycerol (PG), no infant developed RDS while in the absence of PG the incidence of RDS was 16.7% and 14.4%, respectively. In the presence of a mature lecithin/sphingomyelin (L/S) ratio the respective incidence of RDS was 1.6 and 1.8, while with an immature L/S ratio the incidence of RDS was 28.6% and 29%. The incidence of RDS after 37 weeks gestation was 0% among diabetics and 0.6% among non-diabetics. We conclude that amniotic fluid phospholipids are equally predictive of risk for RDS in diabetics as among non-diabetic patients. We suggest that in patients with accurate gestational dating, amniotic fluid analysis for phospholipids might not be necessary to establish fetal lung maturity.

Amniotic Fluid↗
PubMed1987

CGS 15435A, a thromboxane synthetase inhibitor with an extended duration of action: a comparison with dazoxiben.

CGS 15435A, a novel thromboxane (Tx) synthetase inhibitor (5-chloro-1-methyl-2-(3-pyridyl)-3-indolhexanoic acid HCl), had a selectivity for Tx synthetase 100,000-fold greater than that for cyclooxygenase, PGI2 synthetase and lipoxygenase enzymes. In conscious beagles, 1 h following a single 3 mg/kg p.o. dose, serum TxB2 was inhibited 95% by CGS 15435 and 82% by dazoxiben (DAZ). Unlike the short acting Tx synthetase inhibitor DAZ, CGS 15435A significantly inhibited TxB2 formation 4, 6, 12 and 24 h after dosing. Serum levels of 6-keto PGF1 alpha and PGE2 were significantly increased following the administration of either drug. CGS 15435A and DAZ were further examined in a model with known Tx involvement. Thrombotic sudden death, produced in anesthetized rabbits by injection of 0.75 mg/kg arachidonic acid (AA) i.v. resulted in a 45% fall in the platelet count and 0% survival. Pretreatment with DAZ (8.6 mumol/kg i.v.) at 0.25 or 2 h pre-AA resulted in 3 and 42% thrombocytopenia and 100 and 0% survival respectively. CGS 15435A (8.6 mumol/kg i.v.) prevented the increases in plasma TxB2 levels, thrombocytopenia and sudden death with pretreatment at 0.25 h (0% thrombocytopenia and 100% survival) or 24 h (11% thrombocytopenia and 83% survival) before AA. These data indicate that CGS 15435A is a potent and selective Tx synthetase inhibitor with a long duration of action, and suggest that the compound could be useful in chronic, non-symptomatic indications of Tx involvement.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Effects of metoprolol, alone and in combination with lidocaine, on ventricular fibrillation threshold: comparison with atenolol, propranolol, and pindolol.

Metoprolol and other beta-adrenergic blocking drugs are known to exert cardioprotective effects that include significant reduction in occurrence of ventricular fibrillation (VF) following myocardial ischemia and infarction. To help determine the mechanism of these cardioprotective effects, this study evaluated the effect of equipotent beta-blocking doses of metoprolol and three other beta-blockers with differing ancillary properties on ventricular fibrillation threshold (VFT) in the normal canine heart. Metoprolol tartrate (1.0 mg/kg i.v.), atenolol (0.3 mg/kg i.v.), propranolol hydrochloride (0.3 mg/kg i.v.), pindolol (0.03 mg/kg i.v.), or saline control (0.9% NaCl solution; vehicle) was given, alone and in combination with lidocaine (L), to groups of six pentobarbital (32.5 mg/kg i.v.) anesthetized mongrel dogs after control VFT and control isoproterenol-induced (ISO) positive chronotropic effects had been determined. The D- (membrane stabilizing, non-beta blocking) and L- (beta blocking) isomers of propranolol also were administered to separate groups of six anesthetized dogs in a dose of 0.3 mg/kg i.v. Blood samples (venous) were taken before drug or vehicle administration, 10 min after drug/vehicle administration and at half-hour intervals thereafter during experimentation. ISO responses and VFT were determined 5 and 15 min, respectively, after drug/vehicle administration and at half-hour intervals for a total experimental period of 165 min. VF was induced with a train of pulses (5 s, 100 Hz, 3-ms duration, 250-omega resistance) applied by bipolar platinum electrodes to a paced heart (200 beats/min). Voltage (V) was increased every 60 sec (0.25-V increments between 0-3.5 V and 0.5-V increments greater than 3.5 V) until VF occurred. Metoprolol increased VFT significantly (p less than 0.05) and maximally (max delta V = 2.3 +/- 0.7 V) at 135 min postdrug when the ISO-induced increase in heart rate was inhibited (%I ISO) by less than 53%. Max delta V was not significantly increased following i.v. administration of atenolol (0.8 +/- 0.6 V), pindolol (0.1 +/- 0.1 V), or saline (0.1 +/- 0.1 V). Max delta V was 0.5 +/- 0.2 in the D-propranolol-treated group and 0.5 +/- 0.3 in the L-propranolol-treated group. These values did not differ from max delta V obtained in the propranolol-treated group (0.6 +/- 0.4 V). Changes in VFT for all groups were, over time, negatively correlated with %I ISO and were not dependent on membrane stabilizing effect (metoprolol, propranolol (D,DL), pindolol), intrinsic sympathomimetic activity (pindolol), or cardioselectivity (metoprolol, atenolol).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Management of the fetus with urinary tract dilatation.

This report describes our experience with 18 pregnant women who presented to our center with suspected fetal urinary tract dilatation. The patients were divided into 4 groups: group I had unilateral fetal urinary tract dilatation and normal amniotic fluid volume, group II had bilateral dilatation and normal amniotic fluid volume, group III had bilateral dilatation and oligohydramnios, group IV had nonurinary tract malformations in addition to urinary tract dilatation. Patients with normal amniotic fluid volume and either unilateral or bilateral fetal dilatation (groups I and II) had a good pregnancy outcome. Patients with oligohydramnios and bilateral dilatation had a poor pregnancy outcome. No intrauterine surgery or shunting was performed in any of the patients. The initial diagnosis of urinary tract dilatation led to the prenatal diagnosis of major nonurologic malformations (group IV) in 3 patients who also had a poor outcome. An algorithm is presented that reflects our experience with the management of these patients and could serve as a guide for others caring for similar patients.

Amniotic Fluid↗
PubMed1986

Dazoxiben, UK 38,485 and aspirin: duration of effect for preventing thrombotic sudden death in rabbits.

The purpose of this study was to compare the effects of dazoxiben (DAZ), UK 38,485 (UK) and aspirin (ASA) in the prevention of thrombotic sudden death in rabbits. In anesthetized male rabbits, sudden death was produced by intravenous administration of 0.75 mg/kg arachidonic acid (AA). AA increased plasma TxB2 levels from 0.20 +/- 0.10 ng/ml to 8.75 +/- 1.79 ng/ml and produced a 42% reduction in the number of circulating platelets. Death occurred in all animals within 5 minutes. Administration of DAZ (8.6 mumole/kg) 15 min before AA prevented the increase in plasma TxB2, the thrombocytopenia and sudden death while pretreatment with DAZ 2 hr before AA did not. The administration of UK (8.6 mumole/kg) 15 min. 4 hrs or 8 hrs before AA resulted in 100%, 67% and 33% survival, respectively. ASA (110 mumole/kg) administered 2 or 24 hrs before AA inhibited the increase in plasma TxB2 and prevented the fall in platelet counts. All animals pretreated with ASA survived. These data demonstrate that DAZ and UK have only a short to moderate duration of action in preventing AA-induced increases in plasma Tx levels and thrombocytopenia.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Interrelationships among human chorionic gonadotropin (hCG), 17 beta-estradiol, progesterone, and estriol in maternal serum: evidence for an inhibitory effect of the fetal adrenal on secretion of hCG.

In normal pregnancy, maternal serum hCG reaches a maximum concentration about 8-10 weeks after the last menstrual period and then decreases. To investigate the possibility that this decrease in hCG is produced by an inhibitory effect of steroids originating in the feto-placental unit, hCG, progesterone, 17 beta-estradiol, and estriol were determined by specific RIAs in 341 serum specimens obtained from 229 different pregnancies. Expressions for predicted hCG as a function of estimated trophoblastic mass and percent predicted hCG were determined to correct for the increase in hCG with increasing trophoblastic mass. The relationships between hCG and progesterone, 17 beta-estradiol, estriol, or estimated trophoblastic mass were not linear. Expression of the hCG data as percent predicted hCG produced linear relationships between hCG and each of the above steroids. Both hCG itself and percent predicted hCG were shown to have a negative regression on estriol (P less than 0.001) and a positive regression on progesterone (P less than 0.001), but not on 17 beta-estradiol (P greater than 0.05), in a multiple linear regression on all three steroids. These data suggest that hCG production is inhibited by a steroid originating in the fetal adrenal. This inhibitory effect plateaus in late pregnancy, allowing a minor late increase in hCG due to increasing trophoblastic mass.

Adrenal Glands↗
PubMed1983

Megaloblastic anemia after gastric bypass for obesity.

A megaloblastic anemia occurred in a middle-aged woman 6 years after a gastric bypass performed for obesity. Marked deficiencies of both vitamin B12 and folic acid were demonstrated. The Schilling test revealed that the vitamin B12 deficiency was due primarily to inadequate intrinsic factor. Vitamin and mineral deficiencies are relatively common long-term complications in gastric bypass patients, and result from multiple factors including restricted food intake, inadequate gastric digestion, and inadequate intrinsic factor. Bypass patients should receive vitamin-mineral supplements routinely and should have long-term periodic clinical and laboratory evaluation in order to prevent late hematological complications.

Anemia, Macrocytic↗
PubMed1979

Effect of diabetes mellitus on amniotic fluid lecithin/sphingomyelin ratio and respiratory distress syndrome.

Ninety-eight insulin-dependent diabetic patients were cared for during 108 pregnancies following an ambulatory program aimed at close control of blood sugar levels. The incidence of respiratory distress syndrome (RDS) in these patients was not different from that in nondiabetic patients. Fetal pulmonary maturity seemed to progress at a normal rate as evidenced by an equal incidence of mature lecithin/sphingomyelin (L/S) ratios at various stages of gestation in diabetic and nondiabetic patients. There was no evidence that Class B and C diabetic patients have delayed fetal lung maturation or that Class E, F, and R patients have accelerated maturation. It is concluded that careful metabolic control of the pregnant diabetic patient results in a normal process of fetal pulmonary maturation without increased risk of RDS.

Amniotic Fluid↗
PubMed1979

Evaluation of a program of bed rest in the treatment of chronic hypertension in pregnancy.

Sixty-six patients with chronic hypertension were cared for during a total of 72 pregnancies. Patients were treated at home primarily by greater than or equal to 4 hours of bed rest daily in the left recumbent position. Only patients whose diastolic blood pressures remained greater than 110 mmHg were treated with hydralazine (Apresoline, Ciba). With this plan of treatment there were only 3 perinatal deaths for an uncorrected perinatal mortality of 4.1% (1.4% corrected). Twenty-nine percent of the patients had babies that were small for gestational age, 13.8% had positive oxytocin challenge tests, and 36.8% developed superimposed preeclampsia. When compared with the outcome of previous pregnancies, the program of bed rest lowered perinatal mortality from 16.8 to 8.8%. Thus, it is suggested that bed rest together with the avoidance of diuretics and the judicious use of hydralazine results in the most favorable fetal outcome.

Bed Rest↗
PubMed1978

Screening for fetal and neonatal risk in the postdate pregnancy.

One hundred four postdate pregnancies were managed according to a well-defined protocol calling for weekly oxytocin challenge tests and urinary estriols three times per week. Although the perinatal mortality rate in these patients was not increased there was a significant increase in the incidence of neonatal morbidity and complications. The clinical syndrome of dysmaturity was seen in 20 per cent of the neonates. When meconium was present in the amniotic fluid the incidence of neonatal and fetal complications was higher. The cesarean section rate was twice the normal rate, with nonprogression of labor being the commonest indication. It is recommended that: (1) pregnancies carried beyond 42 weeks do not require termination simply because they are post dates; (2) all postdate patients should be monitored during labor; (3) trained personnel to initiate neonatal resuscitation should be present at each postdate delivery.

Amniocentesis↗
PubMed1975

Measles pneumonia. Bacterial suprainfection as a complicating factor.

During a 3 1/2-month period, 32 previously healthy young men were first seen typical prodromal symptoms and signs of measles. On admission or within 48 hours of admission, 16 patients (50%) manifested physical signs and roentgenographic evidence of pneumonia. Of these 16 patients, ten (63%) were found to have bacterial suprainfection or colonization confirmed by culture of transtracheal aspirates. From six of these ten patients, Neisseria meningitidis serogroup Y was isolated as the sole organism responsible for suprainfection. In the other patients, Haemophilus species, Neisseria species (not N gonorrheae or N meningitidis), Streptococcus pneumoniae, and beta-hemolytic Streptococcus (not group A or D were isolated alone or in combination. The data suggest that bacterial supra-infection associated with measles pneumonia is not unusual in adults and N meningitidis serogroup Y is a potential pathogen of the lower respiratory tract.

Adolescent↗