PubMed Health⌕ Search

Biomedical subjects

D Edwards

Publications and source records attributed to D Edwards.

At least 109 records · Page 6Linked to original sources
PubMed1987

The relaxant action of BRL 34915 in rat uterus.

1 BRL 34915 (0.04-1.3 microM) caused concentration-dependent inhibition of spontaneous phasic spasms of the isolated uterus of the term pregnant rat and this effect was not antagonized by propranolol. Spasms evoked by low concentrations of KCl (less than 20 mM) were inhibited by BRL 34915 but those evoked by higher concentrations (greater than 40 mM) were unaffected. 2 In experiments using extracellular electrical recording, BRL 34915 (10 microM) selectively inhibited oxytocin-induced phasic spasms and the associated spike activity but had little effect on the tonic component of the spasms. BRL 34915, as an inhibitor of phasic spasms to oxytocin (0.2 nM), was antagonized by procaine (0.3 and 1 mM). 3 BRL 34915 (10 microM) did not inhibit Ca2+-induced spasm of saponin-skinned thin myometrial strips. 4 Intracellular microelectrode recording from myometrial strips showed that BRL 34915 (10 microM) inhibited action potentials and phasic spasms in the presence of oxytocin (0.2 nM) and produced a hyperpolarization of 5 mV. 5 In single myometrial cells under current or voltage clamp, BRL 34915 (10 microM) had no effect on action potentials and inward current in Ca2+- or Ba2+-containing media in the presence of tetraethylammonium, 4-aminopyridine and caesium chloride. In the absence of these K+-channel inhibitors, BRL 34915 had no effect on resting membrane potential, membrane resistance, action potential, inward current or outward current. 6 BRL 34915 (1 or 10 microM) had no effect on 86Rb efflux from myometrial strips. 86Rb efflux was increased by oxytocin (0.2 and 20 nM). 7 The relaxant profile of BRL 34915 in the rat uterus is similar to that described for other smooth muscles where an action to open membrane K+-channels has been proposed. BRL 34915 inhibited spike production but produced only a small hyperpolarization without a detectable increase in 86Rb efflux. Membrane resistance and transmembrane currents were unaffected. These results suggest that in the uterus the effects of BRL 34915 may be restricted to K+-channels involved in the production of pacemaker activity.

Animals↗
PubMed1987

Effect of plasma membrane fluidity on serotonin transport by endothelial cells.

To evaluate the effect of plasma membrane fluidity of lung endothelial cells on serotonin transport, porcine pulmonary artery endothelial cells were incubated for 3 h with either 0.1 mM cholesterol hemisuccinate, 0.1 mM cis-vaccenic acid, or vehicle (control), after which plasma membrane fluidity and serotonin transport were measured. Fluorescence spectroscopy was used to measure fluidity in the plasma membrane. Serotonin uptake was calculated from the disappearance of [14C]-serotonin from the culture medium. Cholesterol decreased fluidity in the subpolar head group and central and midacyl side-chain regions of the plasma membrane and decreased serotonin transport, whereas cis-vaccenic acid increased fluidity in the central and midacyl side-chain regions of the plasma membrane and also increased serotonin transport. Cis-vaccenic acid had no effect on fluidity in the subpolar head group region of the plasma membrane. These results provide evidence that the physical state of the central and midacyl chains within the pulmonary artery endothelial cell plasma membrane lipid bilayer modulates transmembrane transport of serotonin by these cells.

Animals↗
PubMed1987

Effects of fasting on serum lactogenic hormone concentrations during mid- and late pregnancy in mice.

Hormonal and metabolic responses to fasting were studied in pregnant Swiss Webster mice. Food was removed from pregnant mice 12, 24, 36, or 48 h before death on day 12 or 15 of pregnancy. Serum mouse placental lactogen-II (mPL-II), mouse growth hormone (mGH), mouse prolactin (mPRL), free fatty acids (FFA), and glucose concentrations were determined for each group. In comparing fasted animals with fed controls, there was a significant increase in the serum mPL-II concentration after 24 and 48 h of fasting on day 12 and after 12, 36, and 48 h of fasting on day 15. Fasting significantly decreased the glucose and increased the FFA concentration of the serum at all fasting periods. Fasting had no effect on serum mPRL or mGH concentrations. In the second part of this study, pregnant mice were fasted for 24 h and then refed for an additional 24 h before being killed on day 12 of pregnancy. The changes in serum mPL-II, glucose, and FFA concentrations that occurred after a 24-h fast on day 12 of pregnancy were completely reversed by refeeding the animals for 24 h. Results from both studies indicate the involvement of mPL-II in the maternal response to fasting in pregnant mice.

Animals↗
PubMed1987

Incidence and costs of incidental appendectomy as a preventive measure.

Statewide hospital discharge data in South Carolina for the period 1979-81 were used to evaluate the effectiveness of the incidental appendectomy performed as a preventive measure. The occurrence of incidental appendectomy exceeded that of appendicitis treated by appendectomy, with population-based rates of 1.13/1,000 and 0.97/1,000 person-years, respectively. Over 64 per cent of appendicitis cases occurred in persons under 25 years of age while 74 per cent of incidental appendectomies occurred in persons age 25 and over. Extrapolating to the nation, the data suggest that 254,250 incidental appendectomies might prevent 3,382 future cases of hospitalized appendicitis. The cost of the prevented cases is estimated as $6,764,000. The cost of the incidental appendectomies would be $20,340,000 if as many as 10 per cent of surgeons' fees were separately charged and twice as much if twice as many were so charged. Information on charges for incidental appendectomies is not readily available.

Adolescent↗
PubMed1987

The efficiency of simulation-based multiple comparisons.

A frequently encountered problem in practice is that of simultaneous interval estimation of p linear combinations of a parameter beta in the setting of (or equivalent to) a univariate linear model. This problem has been solved adequately only in a few settings when the covariance matrix of the estimator is diagonal; in other cases, conservative solutions can be obtained by the methods of Scheffé, Bonferroni, or Sidák (1967, Journal of the American Statistical Association 62, 626-633). Here we investigate the efficiency of using a simulated critical point for exact intervals, which has been suggested before but never put to serious test. We find the simulation-based method to be completely reliable and essentially exact. Sample size savings are substantial (in our settings): 3-19% over the Sidák method, 4-37% over the Bonferroni method, and 27-33% over the Scheffé method. We illustrate the efficiency and flexibility of the simulation-based method with case studies in physiology and marine ecology.

Analysis of Variance↗
PubMed1986

Prophylactic treatment of very premature infants with human surfactant.

We undertook a randomized, controlled trial to determine whether human surfactant administered endotracheally at birth to very premature infants (gestational age, 24 to 29 weeks) would prevent the respiratory distress syndrome or reduce its severity. Thirty-one treated infants (birth weight, 938 +/- 286 g) were compared in a blinded fashion with 29 control infants (birth weight, 964 +/- 174 g). The lecithin/sphingomyelin ratio was less than 2 in all infants, and phosphatidylglycerol was not present in amniotic fluid or tracheal fluids at birth, indicating a deficiency of surfactant in the lungs. The principal dependent variables were neonatal death, the incidence of bronchopulmonary dysplasia, and the infant's requirement for respiratory support (and its complications). The surfactant-treated group had significantly fewer deaths than the control group (16 percent vs. 52 percent, P less than 0.001), fewer cases of bronchopulmonary dysplasia (16 percent vs. 31 percent), and significantly fewer cases of pulmonary interstitial emphysema (P less than 0.001) and pneumothorax (P less than 0.02). Prophylactic treatment with human surfactant also substantially reduced the period of neonatal intensive care. We conclude that treatment with human surfactant offers promise for improving the survival of very premature infants with a surfactant deficiency and for reducing the pulmonary sequelae of the respiratory distress syndrome.

Amniotic Fluid↗
PubMed1986

Performance of normal elderly on the Boston Naming Test.

The Boston Naming Test has enjoyed increasing use in many research studies since its introduction. However, there is little normative data on the age group above 60 years of age. This study presents data from a sample of 58 well-defined healthy elderly males and females between the ages of 60 and 85. In comparison with published normative data, our sample has higher means, smaller standard deviations, and narrower ranges. These results suggest that aging alone does not significantly alter recognition-cued word-finding ability as defined by the Boston Naming Test. Also there is remarkably consistent performance throughout our age range.

Aged↗
PubMed1986

Predictive value of the Boston Naming Test in mild senile dementia of the Alzheimer type.

The prognostic implications of anomia were examined in a group of subjects with mild senile dementia of the Alzheimer type. Anomia was found to correlate with a more rapidly progressive course of illness. A subject's age did not account for the degree of anomia. Duration of illness was not correlated with the degree of anomia or with severity of dementia. The presence of anomia in a subject with mild senile dementia of the Alzheimer type appears to indicate a more rapidly progressive course.

Aged↗
PubMed1986

The characteristics and distribution of monoamine oxidase (MAO) activity in different tissues of the rainbow trout, Salmo gairdneri.

Monoamine oxidase (MAO) activity was determined fluorometrically in brain, intestine, kidney and liver tissues of the rainbow trout, Salmo gairdneri. MAO activity was inhibited by various drugs in a concentration-related manner, with single sigmoid inhibition curves, the inhibitors of type A MAO, harmaline and clorgyline being more effective than deprenyl, an inhibitor of type B MAO. Intestine exhibited greatest MAO activity followed by liver and brain with kidney showing least activity. The Michaelis constants (Km) also showed variability between tissues. Inhibition of MAO by harmaline was non-competitive and dependent on the concentration of substrate present.

Animals↗
PubMed1986

Incidence of pulmonary nodules detected by computed tomography in patients with bronchial carcinoma.

Computed tomography (CT) is more sensitive in detecting pulmonary nodules than conventional chest radiography. The incidence of pulmonary nodules on thoracic CT scans, not visible on chest radiographs, in patients with small-cell carcinoma of the bronchus (SCCB) was 27%, and in patients with non-small-cell carcinoma (non-SCCB) the incidence was 28%. Some of these nodules may be malignant. This has implications for the surgical staging of patients with lung cancer in the United Kingdom, where there is a lower incidence of benign granulomatous nodules than in the USA.

Carcinoma, Bronchogenic↗
PubMed1986

The spasmogenic action of oxytocin in the rat uterus--comparison with other agonists.

A low concentration (0.2 nM) of oxytocin induced phasic tension development in the isolated uterus of the day-22 pregnant rat. Tonic spasm was also induced by higher concentrations of oxytocin (2 and 20 nM). Spasmogenic responses to bradykinin and potassium chloride (KCl) also contained phasic and tonic components while acetylcholine induced tonic spasm only. The phasic component of the responses to oxytocin and to bradykinin and both components of the response to KCl were inhibited by (+)-cis diltiazem (0.1 and 1 microM). The tonic component of the responses to oxytocin and to bradykinin and the responses to acetylcholine were only reduced by (+)-cis diltiazem at concentrations greater than 10 microM. (-)-cis Diltiazem was less potent than (+)-cis diltiazem as an inhibitor of calcium (Ca2+)-induced spasm in a depolarizing medium and of the phasic spasms induced by oxytocin. The two isomers were of similar potency as inhibitors of oxytocin-induced tonic spasm. Spasmogenic responses to oxytocin, bradykinin, acetylcholine and KCl were decreased when uteri were bathed in media which were Ca2+-free or of low Na+ content. However, there was no correlation between the rank order of sensitivity of the four spasmogens to the changed media and to their inhibition by (+)-cis diltiazem. Oxytocin (0.2 nM) increased the frequency, duration and amplitude of spike activity, measured by extracellular electrical recording, in parallel with enhancement of phasic tension development. With higher concentrations of oxytocin (2 and 20 nM) spike firing was initially continuous but often subsequently ceased despite the associated tonic contracture. After incubation in (+)-cis diltiazem (10 microM), oxytocin (0.2, 2 and 20 nM) produced graded tonic spasm without spike activity. Oxytocin (0.2 nM) produced a small increase in 45Ca2+ influx into myometrium as assessed by the 'lanthanum method'. Higher concentrations of oxytocin (2 and 20 nM) did not increase 45Ca2+ influx. It is concluded that the phasic component of the response of the uterus to oxytocin and bradykinin is associated with Ca2+ influx via voltage-dependent Ca2+ channels. The tonic component is due to another mechanism(s) which does not appear to involve Ca2+ influx. All of the spasmogenic response to KCl can be explained by Ca2+ influx through voltage-dependent Ca2+ channels. These channels do not appear to be involved in the spasmogenic response to acetylcholine.

Acetylcholine↗
PubMed1986

Association between diaphragm use and asymptomatic bacteriuria.

The prevalence of asymptomatic bacteriuria was assessed in women using different contraceptive methods. Three hundred and twenty women attending a family planning centre were studied, 80 in each of the following groups: diaphragms, intrauterine contraceptive devices (IUCDs), oral contraceptives (OCs) and no contraception. The numbers with asymptomatic bacteriuria in the 4 groups were as follows: diaphragm - 12 (all E coli); IUCD - 3 (E coli; P mirabilis; S saprophyticus); OC - 5 (all E coli); no contraception - 4 (3 E coli; 1 S saprophyticus). The prevalence of Gram-negative bacteriuria in women using diaphragms was significantly higher than for women in the other groups (chi 2 = 8.98; p less than 0.05). Factors such as parity, numbers of sexual partners and frequency of sexual intercourse had no apparent effect. The use of diaphragms may contribute to the risk of Gram-negative urinary tract infections in sexually active women.

Adolescent↗
PubMed1986

Cardiogenic shock without a critically raised left ventricular end diastolic pressure: management and outcome in eighteen patients.

Eighteen patients in whom shock developed after acute myocardial infarction are described. There was electrocardiographic evidence of acute inferior infarction in 11, of inferolateral infarction in three, and of anteroseptal infarction in four. In all cases the right atrial pressure was the same as or exceeded the end expiratory pulmonary artery wedge pressure. Plasma volume expansion of 100-2500 ml was needed to produce an optimum pulmonary artery wedge pressure. Eleven patients needed additional inotropic support with dopamine. Despite the absence of a critical increase in pulmonary artery wedge pressure, potential or actual hypoxia was almost always present. Six patients needed endotracheal intubation and mechanical ventilation because they had severe hypoxia that was unresponsive to supplemental inspired oxygen. Life threatening arrhythmias were also common (ventricular fibrillation in seven patients and complete heart block in four). Five patients died. All surviving patients are well and only one requires treatment for heart failure.

Aged↗
PubMed1986

The role of computerised tomography in intervertebral disc prolapse.

Computerised tomography of the lumbar spine was performed on 22 patients with clinical evidence of prolapse of an intervertebral disc and normal or equivocal radiculograms. Of 11 patients with positive scans who had an operation the presence of pathology was confirmed in 10. Although CT scanning is always helpful in diagnosing disc disorders, where facilities are scarce (as in Great Britain) it is best employed in patients with negative or non-contributory radiculography.

Adult↗