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Biomedical subjects

D Edwards

Publications and source records attributed to D Edwards.

At least 145 records · Page 8Linked to original sources
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↗
PubMed1985

Development of new renal scars: a collaborative study.

In a study of the factors surrounding the development of renal scars clinical data and serial radiographs were analysed in 74 infants and children (66 girls and eight boys) without duplex kidney or obstruction. The development of new scars was seen radiologically in 87 kidneys (74 previously normal and 13 previously scarred). New scarring was extensive in 16 kidneys. Thirty four children were aged 5 or over when scarring occurred. Urinary infection occurred in all the children. Diagnosis and effective treatment were delayed in 45 of them; 58 suffered further urinary infections between the baseline intravenous urogram and the first showing new scarring. Vesicoureteric reflux was seen in 67 of the children. Investigation and treatment varied widely, and few children received long term prophylaxis. Social problems interfered with the management of 22 children. Early diagnosis, prompt effective treatment, investigation, and long term supervision of children with urinary infection are essential if renal scarring is to be reduced; those over the age of 5 are still vulnerable.

Child↗
PubMed1985

Chlamydia trachomatis infection at a family planning clinic.

Endocervical samples were taken for the detection of Chlamydia trachomatis from 500 consecutive patients attending a family planning clinic. The Microtrak direct specimen immunofluorescence test was used. Swabs from 79 patients (15.8%) were positive for chlamydia. Seventy-one (95%) of these patients were symptom free, and 39.8% were under 20 years old. Twenty-one patients were pregnant, seven (33%) had chlamydia. Those positive for chlamydia had twice the frequency of abnormal smears and other sexually transmitted infections as those who were negative. Contraceptive use was similar except that intrauterine devices were used less frequently by patients with chlamydia infection. This report indicates the frequent occurrence of Chlamydia trachomatis infection in New Zealand and that newly developed methods of diagnosis enable us to identify and treat those with this infection. Characteristically these patients are under 20, have multiple partners and a high incidence of abnormal smears and other sexually transmitted infections.

Adolescent↗