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Biomedical subjects

T G Williams

Publications and source records attributed to T G Williams.

34 records · Page 2Linked to original sources
PubMed1987

The relationship between cadmium, zinc, and birth weight in pregnant women who smoke.

It is universally accepted that smoking during pregnancy results in decreased infant birth weight. However, the mechanism for decreased birth weight is not completely understood. This study tested the hypothesis that the cadmium/zinc interaction in the maternal-fetal-placental unit of the mother who smokes could be related to birth weight. Thiocyanate was used as the index of smoking status and atomic absorption spectroscopy was used to determine trace elements. Results show that cord vein red blood cell zinc and maternal whole blood cadmium levels are significant predictors of infant birth weight when variance that is due to clinical factors and thiocyanate is controlled with stepwise multiple regression techniques (n = 202). Bivariate correlation techniques showed that the factors affecting birth weight were different in the smoking and nonsmoking groups. For example, in nonsmokers (n = 125), the cord vein red blood cell zinc level was positively related to birth weight. In smokers (n = 77), maternal whole blood cadmium, placental cadmium, and placental zinc levels were negatively related to birth weight; the ratio of placental zinc to placental cadmium and the cord vein red blood cell zinc level were positively related to birth weight. The results suggest that increased maternal cadmium and decreased cord vein red blood cell zinc levels in infants of smokers may be significant clinically since increased maternal whole blood cadmium and decreased cord vein red blood cell zinc levels are both significantly related to decreased birth weight.

Birth Weight↗
PubMed1987

The Role of External Carbonic Anhydrase in Inorganic Carbon Acquisition by Chlamydomonas reinhardii at Alkaline pH.

The role of external carbonic anhydrase in inorganic carbon acquisition and photosynthesis by Chlamydomonas reinhardii at alkaline pH (8.0) was studied. Acetazolamide (50 micromolar) completely inhibited external carbonic anhydrase (CA) activity as determined from isotopic disequilibrium experiments. Under these conditions, photosynthetic rates at low dissolved inorganic carbon (DIC) were far greater than could be maintained by CO(2) supplied from the spontaneous dehydration of HCO(3) (-) thereby showing that C. reinhardii has the ability to utilize exogenous HCO(3) (-). Acetazolamide increased the concentration of DIC required to half-saturate photosynthesis from 38 to 80 micromolar, while it did not affect the maximum photosynthetic rate. External CA activity was also removed from the cell-wall-less mutant (CW-15) by washing. This had no effect on the photosynthetic kinetics of the algae while the addition of acetazolamide to washed cells (CW-15) increased the K((1/2)) (DIC) from 38 to 80 micromolar. Acetazolamide also caused a buildup of the inorganic carbon pool upon NaHCO(3) addition, indicating that this compound partially inhibited internal CA activity. The effects of acetazolamide on the photosynthetic kinetics of C. reinhardii are likely due to the inhibition of internal rather than a consequence of the inhibition of external CA. Further analysis of the isotopic disequilibrium experiments at saturating concentration of DIC provided evidence consistent with active CO(2) transport by C. reinhardii. The observation that C. reinhardii has the ability to take up both CO(2) and bicarbonate throws into question the role of external CA in the accumulation of DIC in this alga.

Journal Article↗
PubMed1987

Neonatal complications following in utero exposure to intravenous ritodrine.

Intravenous administration of ritodrine for tocolysis has been associated with maternal cardiovascular and metabolic changes. Studies with other tocolytic agents, such as isoxsuprine, have shown an increased neonatal morbidity among infants born soon after failure of such therapy. We examined the potential side effects of maternal intravenous ritodrine therapy in 58 neonates born within 12 h following discontinuation of maternal medication. 'Low dextrostix' was significantly greater in the ritodrine exposed neonates (p less than 0.05) than in the controls. It occurred within a mean 1.0 +/- 0.5 h following birth. The mean 1 min and 5 min Apgar scores, neonatal pH, bicarbonate levels, hypotension and neonatal mortality were comparable in the ritodrine-exposed and control groups of neonates. The occurrence of any of the neonatal morbidity variables, including 'low dextrostix' was not related either to the total dose of ritodrine used or to the interval between drug discontinuation and delivery. Administration of ritodrine by the standard protocol to stop preterm labor is not associated with any significant increase in neonatal morbidity.

Female↗
PubMed1986

Photosynthetic Adaptation by Synechococcus leopoliensis in Response to Exogenous Dissolved Inorganic Carbon.

Synechococcus leopoliensis was grown over a wide range of dissolved inorganic carbon (DIC) concentrations (4-25,000 micromolar) which were obtained by varying culture pH (6.2-9.6) and the CO(2) concentration of the gas stream (36-50,000 microliters per liter). The [DIC] required to half-saturate photosynthesis (K((1/2)) (DIC)) was found to vary depending upon the ambient DIC concentration at which the cells were grown. Low [DIC] grown cells exhibited low values of K((1/2)) (DIC) (4.7 micromolar) whereas cells grown at high [DIC] exhibited high values of K((1/2)) (DIC) (1-2.5 millimolar). Intermediate concentrations of DIC produced intermediate values. Changes in K((1/2)) (DIC) appeared to be solely a function of [DIC] and were independent of both culture pH and CO(2) concentration. As changes in K((1/2)) (DIC) occur in response to DIC concentrations commonly found in natural systems we suggest this adaptation may be of ecological significance.

Journal Article↗
PubMed1985

The diagnosis of aortic graft-enteric fistulae by computed tomography.

A number of techniques have been used to diagnose aortic graft-enteric fistulae. These are reviewed and their value assessed. Three patients are described in whom the diagnosis was correctly made from characteristic appearances seen on a computed tomography (CT) scan. Further experience may show that CT scanning has an important role in the detection of this condition.

Aged↗
PubMed1985

Maternal obesity as a risk factor in gestational diabetes.

Maternal obesity has been associated with both gestational diabetes mellitus (GDM) and neonatal macrosomia. Most studies of obesity in pregnancy have demonstrated an increased risk for GDM. However, the contribution of obesity as an added risk in GDM has not been examined. The purpose of this study was to examine the contribution of obesity as a risk factor to perinatal morbidity in gestationally diabetic women by comparing the maternal and neonatal outcome in obese and nonobese gestationally diabetic women. From 1979 to 1983, the maternal, intrapartum, and neonatal characteristics of all prepartum gravid patients with GDM were examined. Of the 158 patients with documented GDM, 62 (39%) were obese (weight greater than 90 kg). There was no difference in maternal age (obese 29.3 +/- 5.4 years, nonobese 28.7 +/- 6.5 years) parity, or prepartum risk score between the obese and nonobese patients. The incidence of prematurity, pre-eclampsia, fetal distress, and primary cesarean sections were not different between the groups. There were no differences in Apgar scores, gestational age, or perinatal morbidity. However, the obese patients delivered heavier neonates expressed as mean birthweight (obese 3667 +/- 682 gms, nonobese 3331 +/- 750 gms. P less than .01), the number of macrosomic (greater than 4 kg) neonates (obese 37%, nonobese 14%, P less than .001) and K-score, (obese 0.8 +/- 1, nonobese 0.4 +/- 9, P less than .05). These data indicate that obese patients with GDM have an increased risk of neonatal macrosomia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Gestational diabetes mellitus. Is further improvement necessary?

The maternal antepartum, intrapartum, and neonatal characteristics of 158 patients with gestational diabetes mellitus (GDM) attending a large teaching hospital between 1979 and 1983 were described and compared with a matched nondiabetic control group. The primary cesarean section rate in patients with GDM (18%) was significantly greater than in the control group (11%, P less than 0.04). Neonatal macrosomia, as reflected in mean birthweight (P less than 0.04), the number of neonates weighing greater than 4 kg (P less than 0.05) and large-for-gestational-age infants (P less than 0.05), and the birthweight adjusted for gestational age (K-score, P less than 0.01) was significantly increased in the diabetic group. The characteristics of patients with GDM treated with diet alone and diet and insulin together were examined. The insulin-therapy group was characterized by more patients older than 25 yr (P less than 0.01) and a higher mean birthweight (3743 +/- 677 g) (P less than 0.02) than the diet-alone group. This may reflect an increased magnitude of glucose intolerance in the insulin-treated group. Obese patients with GDM delivered heavier neonates than the nonobese patients with GDM (P less than 0.01). Although there was no difference between the groups, perinatal mortality was present in this study. These data indicate that the major perinatal morbidity in GDM included increased cesarean section for fetal macrosomia. Early diagnosis with strict diagnostic criteria and rigid antenatal surveillance may result in further improvements in outcome.

Birth Weight↗
PubMed1983

Isolated unruptured aneurysm of the left coronary sinus of Valsalva.

An isolated unruptured aneurysm of the left coronary sinus of Valsalva was detected incidentally in a patient with a bicuspid aortic valve in whom the left circumflex coronary artery arose from the right coronary artery. With the patient on cardiopulmonary bypass, the mouth of the aneurysm was closed by suturing the reflected posterior cusp of the aortic valve to the aortic root. A Starr-Edwards prosthetic aortic valve was inserted, and an aortocoronary saphenous vein bypass graft maintained good blood flow down the left anterior descending coronary artery. Previous reports of this rare condition and its treatment are discussed.

Aortic Aneurysm↗
PubMed1977

Spontaneous rupture of the abdominal aorta.

Fatal spontaneous rupture of the lower abdominal aorta in a previously healthy 61-year-old woman is reported; the possibility that she had the Ehlers-Danlos syndrome is discussed.

Aorta, Abdominal↗
PubMed1975

Hangman's fracture.

Of four hangman's fractures of the axis, three occurred in road accidents and were stable, undisplaced and free of neurological signs, with full recovery after six to twelve weeks in a cervical collar. The fourth fracture occurred in a fall with profound tetraparesis from haemorrhage into the spinal cord, and the patient died a week later. There are two types of hangman's fracture: that of the axis pedicle, which results from extension and compression of the cervical column, is more common than usually supposed because of the slight symptoms it causes.

Adult↗
PubMedDate not supplied

The prolactin response to flutroline hydrochloride in schizophrenic patients.

Flutroline hydrochloride, a gamma carboline manifesting neuroleptic activity, was administered in a double-blind fashion in single daily dosages of 1, 5, 10, 20, and 100 mg to 48 hospitalized schizophrenic patients over a period of four weeks. During this period, weekly evaluations were made of response employing standardized psychiatric ratings. Plasma prolactin (PRL) levels were obtained at the termination of previous neuroleptic medication and at two-week intervals during treatment with the investigational compound. Examination of the initial PRL levels indicated that they could be grouped into those above, within, and below the normal range. Comparisons of these initial levels with those following the administration of flutroline suggested an improved methodology for determining optimal neuroleptic dosage.

Adolescent↗