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Biomedical subjects

G D Anderson

Publications and source records attributed to G D Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1986

The effect of carbohydrate overfeeding on blood pressure in the pregnant, spontaneously hypertensive rat.

Carbohydrate overfeeding increases blood pressure in the spontaneously hypertensive rat. This study was undertaken to determine if dietary carbohydrate supplementation throughout pregnancy could prevent the normal fall in blood pressure during the last week of gestation. Systolic blood pressure in the control-fed pregnant rats decreased progressively during the last week and was in the normotensive range by term; that of the carbohydrate-supplemented, pregnant rats remained high and was not significantly lower than that of nonpregnant rats at any time. At term, daily urinary norepinephrine excretion, but not epinephrine excretion, by the carbohydrate-supplemented pregnant rats was twice that of control-fed nonpregnant and pregnant rats, suggesting that the hypertension was due to increased sympathetic nervous activity. Carbohydrate supplementation had no effect on blood pressure or catecholamine excretion in pregnant, normotensive Wistar-Kyoto rats. There were no differences in litter size or mean birth weight between diet treatment groups of either strain.

Animals↗
PubMed1986

Eclampsia. V. The incidence of nonpreventable eclampsia.

The development of eclamptic convulsions is an obstetric complication that is generally considered to be avoidable. The purpose of this study was to investigate the perinatal events associated with 179 consecutive cases of eclampsia, in order to identify specific preventable factors. Based on a careful analysis of medical care received before the onset of eclampsia, the following factors were judged to be at least partially responsible for the failure to prevent eclamptic convulsions: physician error (n = 65), magnesium sulfate failure (n = 23), late-onset eclampsia (n = 22), early onset (less than 21 weeks) preeclampsia/eclampsia (n = 5), abrupt onset eclampsia (n = 32), and failure of patient to start prenatal care before the onset of eclampsia (n = 34). Fifty-six (31.3%) of the patients received obstetric care that met or exceeded all current standards for delivery of obstetric services. These cases were classified as "unavoidable."

Adolescent↗
PubMed1986

Effect of hexoprenaline on uteroplacental blood flow in the pregnant rat.

The effect of beta-adrenergic agonists on uteroplacental blood flow is controversial. Human studies, with the use of indirect methods to assess uteroplacental blood flow, show conflicting results. Animal studies in the near-term pregnant sheep model have the disadvantages that the sheep has a syndesmochorial placenta and that the uteroplacental vessels are thought to be maximally dilated near term. The effect of hexoprenaline, a new beta 2-sympathomimetic drug, was assessed in the awake pregnant rat on day 14 of gestation by means of the radionuclide-labeled microsphere method. Hexoprenaline increased placental blood flow by 198% and distribution of cardiac output to the placentas by 229%. Renal blood flow was reduced by 24%. Saline solution administration produced no significant effects.

Animals↗
PubMed1986

Effect of long-term administration of beta 2-sympathomimetic drug in the diet-restricted pregnant rat model.

To assess whether the maternal-fetal balance could be altered in favor of the fetus during malnutrition by increasing uteroplacental blood flow, 0.5 mg of hexoprenaline per day was added to the diet of one group of diet-restricted rats, while another group served as controls. The radionuclide-labeled microsphere method was used to determine blood flow to the maternal placentas and other organs. Maternal carcass weight but not fetal or placental weights were increased in the hexoprenaline-fed rats. Blood flow to the ileum, jejunum, hepatic artery, kidneys, and placentas was significantly greater in the hexoprenaline group compared with those rats fed the restricted diet alone. Although the placental blood flow was increased in the hexoprenaline-fed rats, the supply of nutrients remained restricted, and in the mother the inherent maternal-fetal balance was maintained by an increase in the blood flow to the liver and small intestine.

Animals↗
PubMed1986

Differential response of amygdaloid neurons to clozapine and haloperidol: effects of repeated administration.

Rats were pretreated with saline or with behaviorally equivalent doses of clozapine (10.0 mg/kg) or haloperidol (1.0 mg/kg) twice daily for six consecutive days. On the following day, amygdaloid neurons in clozapine-pretreated rats responded to a challenge injection of this drug with a significantly greater increase in firing rate than saline controls. In contrast, amygdaloid neurons generally remained unresponsive to haloperidol even when pretreatment with this drug was extended to 13 days. Neither clozapine nor haloperidol pretreatment, however, altered the response of amygdaloid neurons to d-amphetamine administered after a four-day washout period. Amphetamine inhibited amygdaloid activity to a comparable extent in all rats. Taken together, these results implicate the amygdaloid complex as an important site of action of clozapine and related antischizophrenic drugs.

Amygdala↗
PubMed1986

Catecholamine-mediated reduction in uteroplacental blood flow in the diet-restricted, term-pregnant rat.

To determine whether the reduction in maternal placental blood flow associated with malnutrition during pregnancy results from alpha-adrenergic vasoconstriction, we measured cardiac output, uteroplacental blood flow and uteroplacental vascular resistance in ad libitum-fed and in 50% diet-restricted term-pregnant rats, using radioactive-labeled microspheres before, and again after, alpha-adrenergic receptor blockade with phenoxybenzamine. Uteroplacental blood flow in the diet-restricted rats was 40% lower than that of the ad libitum-fed rats, before phenoxybenzamine. Phenoxybenzamine caused a 50% reduction in mean blood pressure in both the ad libitum-fed and diet-restricted rats, but did not alter cardiac output. Phenoxybenzamine decreased preplacental vascular resistance in the diet-restricted rats, resulting in no significant reduction of placental blood flow. In the ad libitum-fed rats, on the other hand, phenoxybenzamine did not alter preplacental vascular resistance, and placental blood flow decreased 45% with the fall in blood pressure. Myometrial vascular resistance was unaffected by phenoxybenzamine in either group, and myometrial blood flow decreased with the fall in blood pressure in both groups. Thus, the decreased uteroplacental blood flow associated with diet restriction is the result of increased uteroplacental alpha-adrenergic vasomotor tone.

Animals↗
PubMed1986

Partial plasma exchange transfusion improves cerebral hemodynamics in symptomatic neonatal polycythemia.

Cerebral arterial pulsatile flow changes and the effect of partial plasma exchange transfusion on these pulsatile flow patterns were studied in neonatal polycythemia/hyperviscosity syndrome by transcutaneous Doppler technique. Twenty-two infants with cord blood hematocrit greater than 58% (greater than 2 SD above the mean) were studied from a total of 2,400 infants who were screened for cord hematocrit over a 6-month period. Each of 22 infants had the following initial studies: radial artery hematocrit, viscosity, intracranial pressure measurement, and anterior cerebral arterial Doppler study to determine pulsatility index, mean systolic, mean end diastolic, and mean flow velocities, and area underneath the curve of the velocity tracings/min. Twelve of 22 infants had radial artery hematocrit less than 63%, were normoviscous (less than 13.5 cps, 11.25 sec-1) and were designated as control infants. Ten (study infants) were polycythemic (hematocrit greater than or equal to 63%) and hyperviscous (greater than or equal to 13.5 cps, 11.25 sec-1). All study patients were treated by partial plasma exchange transfusion. Initial studies were repeated after exchange transfusion. Control infants were not treated. Prior to exchange procedure, the polycythemic hyperviscous infants had significantly higher hematocrit, viscosity, and pulsatility index; the other Doppler measurements and heart rate were lower than those of control babies. The exchange procedure resulted in significantly decreased hematocrit, viscosity, and pulsatility index and increase in the other Doppler measurements, heart rate, and intracranial pressure. All postexchange measurements of study infants were not statistically different from the control infants. These data suggest that neonatal polycythemia/hyperviscosity syndrome may be associated with abnormal cerebral hemodynamics that could improve with partial plasma exchange transfusion.

Blood Viscosity↗
PubMed1986

Fetal distress after hydralazine therapy for severe pregnancy-induced hypertension.

Hydralazine is the most commonly used antihypertensive agent for patients with severe toxemic states. Its use, however, can produce hypotension and acute uteroplacental insufficiency, resulting in fetal distress. Our review of hospital charts of severely preeclamptic or eclamptic patients observed during a two-year period showed that 24 of 77 patients were treated with hydralazine; the remainder were not. Of those receiving hydralazine, 38% (9/24) were delivered by cesarean section because of fetal distress, as compared to 9% (5/53) of those not receiving hydralazine (P less than .01). Of patients whose hydralazine therapy was inappropriate, 82% (9/11) incurred fetal distress versus 38% (5/13) when hydralazine was appropriately administered (P less than .05). In patients receiving hydralazine, fetal distress is in part the consequence of the severity of the disease, but excess use of antihypertensive agents appears to increase this risk.

Acute Disease↗
PubMed1986

Hexoprenaline tocolysis for intrapartum fetal distress and acidosis.

Hexoprenaline, a selective beta 2-sympathomimetic drug, was administered to 12 patients with severe distress in labor. The fetal distress was documented by fetal heart rate abnormalities in association with a fetal scalp blood pH of less than 7.20. The mean fetal scalp pH was 7.17 +/- 0.17 before treatment. A 7.5- to 10-micrograms intravenous bolus of hexoprenaline was followed by an intravenous infusion titrated to inhibit uterine contractions. According to protocol, all patients delivered by cesarean section approximately 40 minutes after the bolus injection. The mean cord blood pH was 7.31 +/- 0.06. No infant had a five-minute Apgar score of less than 8, and there were no significant maternal or fetal side effects.

Acid-Base Equilibrium↗
PubMed1986

Pregnancy outcome of intensive therapy in severe hypertension in first trimester.

The purpose of the present clinical investigation was to determine the maternal and perinatal outcome associated with continuing pregnancy in 44 consecutive patients with severe chronic hypertension in the first trimester. Each patient was observed closely throughout pregnancy with frequent prenatal visits and intensive monitoring of the clinical status of both mother and fetus. There were no maternal deaths, but morbidity was very significant. Most patients required repeated hospitalizations and on many occasions parenteral medications were used to reduce blood pressure. Nineteen had transient and one permanent renal deterioration. These results confirm that pregnancy in women with severe hypertension is beset with considerable morbidity, but with expert intensive care, gestations can be concluded successfully in those women who refuse termination. Twenty-three patients (52%) developed superimposed preeclampsia, one patient developed pleural effusion, and one patient had postpartum hypertensive encephalopathy. In addition, there was no evidence of late puerperal maternal cardiovascular or renal damage on long-term follow-up. There were ten stillbirths and one neonatal death for an overall perinatal mortality of 25%. Seventy percent of the infants were delivered before 37 weeks' gestation, and 19 infants (43%) were small for gestational age. However, all the perinatal deaths and most of the neonatal morbidity occurred among the 23 patients with superimposed preeclampsia.

Adult↗
PubMed1985

Eclampsia. IV. Neurological findings and future outcome.

Sixty-five patients with eclampsia were longitudinally evaluated regarding neurological abnormalities and maternal outcome (6 to 42 months) after eclampsia. Electroencephalograms were obtained on all patients during the subsequent 6 months. Computerized axial tomographic scans (n = 20) and cerebral arteriograms (n = 3) were obtained on patients with neurological deficits and/or those with an atypical clinical course. The electroencephalogram was abnormal in 49 patients (75%) at initial assessment but gradually returned to normal in all observed patients within 6 months. Cerebral arteriograms and computerized axial tomographic scans were normal in each patient studied. None of the patients had neurological deficits or subsequent convulsions on follow-up examination. Thirty-eight patients had one or more subsequent pregnancies without recurrent eclampsia, but 14 (37%) had pregnancy-induced hypertension. The findings suggest that neurological events of eclampsia are acute and transient and that long-term neurological deficit is rare in the properly managed patient. Computerized axial tomography and electroencephalography are rarely indicated in the management of such patients.

Adolescent↗
PubMed1985

Maternal and perinatal outcome of conservative management of severe preeclampsia in midtrimester.

Pregnancies complicated by severe preeclampsia in the second trimester are associated with a high incidence of perinatal morbidity and mortality. One way to possibly improve perinatal outcome in these pregnancies is to attempt to prolong the gestation with conservative management. Reported here the results of conservative management of 60 consecutive patients with severe preeclampsia in the second trimester (18 to 27 weeks' gestation). Although there were no maternal mortalities, the morbidity rate for the 60 patients was very high. Severe maternal complications included abruptio placentae (n = 13), eclampsia (n = 10), coagulopathy (n = 5), renal failure (n = 3), hypertensive encephalopathy (n = 2), intracerebral hemorrhage (n = 1), and ruptured hepatic hematoma (n = 1). In addition, perinatal outcome for these pregnancies was exceptionally poor, with 31 of the 60 pregnancies resulting in a stillborn infant, and 21 resulting in a neonatal death, for a total perinatal mortality rate of 87%. Thus, the results of this retrospective study do not support the use of conservative management for pregnancies complicated by severe preeclampsia in the second trimester.

Administration, Oral↗
PubMed1985

Baby Doe: is there really a problem?

A brief survey was done in six major cities of parental complaints about family counseling offered at the time of the birth of a child with Down syndrome. Minimal parental expectations and counseling guidelines are discussed. The need for further parent-professional educational effort is emphasized.

Attitude to Health↗
PubMed1984

Determinants of size at birth in a Canadian population.

Anthropometric, medical, and sociodemographic characteristics and smoking habit of a random sample of postpartum women in a Canadian population were determined. These characteristics were analyzed in relation to the birth size of their babies. With controls for gestational age and fetal sex, the following maternal variables were positively correlated with birth weight: prepregnant weight, weight gain in pregnancy, stature, bicristal and biacromial diameter, calf and upper arm circumference, and triceps and subscapular skinfold thickness. Smoking during pregnancy reduced birth weight by 13 gm per cigarette smoked daily. Similar associations of maternal size and smoking habit were observed with respect to infant length, head circumference, and chest circumference. The predictors of birth weight are proposed for use in adjusting upward or downward the population distribution of birth weight to reflect the individual characteristics of the mother.

Adrenal Cortex Hormones↗
PubMed1984

Obstetric factors and relative risk of neonatal germinal layer/intraventricular hemorrhage.

One hundred fifty-five inborn infants with a birth weight less than or equal to 1,500 gm were prospectively evaluated for germinal layer/intraventricular hemorrhage. Maternal characteristics, obstetric factors, and neonatal condition in the immediate newborn period were analyzed as possible risk factors for germinal layer/intraventricular hemorrhage. Early germinal layer/intraventricular hemorrhage or hemorrhages identified during the first 24 hours of life were observed in 85 (55%) of these infants. Another 37 (24%) had germinal layer/intraventricular hemorrhage after 24 hours of age (late germinal layer/intraventricular hemorrhage). None of the maternal and obstetric variables, including labor, mode of delivery, and presentation, appeared to increase the risk of germinal layer/intraventricular hemorrhage. The immediate neonatal condition, birth weight, gestational age, and intrauterine growth, all influenced the occurrence of germinal layer/intraventricular hemorrhage, especially early germinal layer/intraventricular hemorrhage. We suggest that future studies to investigate the role of maternal or obstetric factors in the pathogenesis of germinal layer/intraventricular hemorrhage should discriminate early from late germinal layer/intraventricular hemorrhage. Obstetric factors are more likely to influence the early onset of germinal layer/intraventricular hemorrhage; their effect, if any, becomes less discernible later.

Anesthesia, Obstetrical↗