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Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 613 records · Page 34Linked to original sources
PubMed1988

Is outcome for general practitioner obstetricians influenced by workload and locality?

Maternal and perinatal morbidity and transfer patterns were examined to assess the influence of the number of deliveries performed by each general practitioner obstetrician and the distance from specialist care. There were statistically significant differences in transfer patterns between urban and rural practitioners and between those practitioners delivering fewer than twenty per year and those delivering twenty or more per year. Antenatally, rural practitioners transferred more of their patients to the base hospital and those practitioners delivering fewer than twenty per year had higher transfer rates than those delivering twenty or more per year. During labour the transfer rate was lowest for rural practitioners delivering more than 20 babies per year. Urban practitioners in comparison to rural practitioners delivered a significantly greater proportion of women who were considered to have a moderate or high obstetric risk. No association was found between the number of deliveries undertaken by general practitioners both urban and rural and maternal and neonatal morbidity. The proportion of women and neonates who had a score which indicated a less favourable outcome for maternal and neonatal morbidity, was higher for urban practitioners than for rural practitioners.

Delivery, Obstetric↗
PubMed1988

Ferrous intraocular foreign bodies and magnetic resonance imaging.

We placed various sized ferrous foreign bodies in and around the eye, sclera, and orbit in a rabbit model before performing magnetic resonance imaging studies. All foreign bodies were detected on plain x-rays. Only one of the largest fragments (3 x 1 x 1 mm) demonstrated movement on exposure to the magnetic field.

Animals↗
PubMed1988

Blood lead, intelligence, reading attainment, and behaviour in eleven year old children in Dunedin, New Zealand.

A study of blood lead levels and intelligence, reading, and behaviour problems was carried out using a sample of 579 Dunedin 11-yr-old children. The results suggested that when account was taken of social, environmental, and background factors, raised blood lead is associated with a small but statistically significant increase in children's general behaviour problems as reported by both parents and teachers. These results applied especially to the more specific problems of inattention and hyperactivity.

Achievement↗
PubMed1988

Stereoacuity levels and vision problems in children from 7 to 11 years.

A longitudinal study of stereoacuity levels of 859 children at 7 years, 811 children at 9 years and 796 children at 11 years was conducted using the TNO random dot stereotest. The prevalence of defective stereoscopic vision was found to be between 2.1 and 3.2 per cent. A further 10-16 per cent of children had only moderate stereoacuity levels when compared with their peers. The stereoacuity levels achieved by most of the children improved with age, but the rank order correlations for the stereoacuity levels between ages 7 and 9, and ages 9 and 11, were small. Defective stereopsis and poor stereoacuity levels were clearly associated with manifest strabismus and problems of visual acuity, and if failure to pass the quantitative plates was a cut-off point for screening purposes most of the children with visual problems would have been identified.

Child↗
PubMed1988

Myocardial kinetics of technetium-99m-hexakis-2-methoxy-2-methylpropyl-isonitrile.

To study the potential usefulness of technetium-99m hexakis-2-methoxy-2-methylpropyl-isonitrile (Tc-MIBI) as a cardiac perfusion imaging agent, the left circumflex coronary arteries of 12 dogs were partially occluded. Eight additional control dogs had no coronary artery stenosis. Myocardial Tc-MIBI activities in the left circumflex and left anterior descending zones were continuously monitored by miniature implantable radiation detectors for 4 hr after administration of the isotope. The dogs were then killed. Serial gamma camera images were also acquired during the study. Heart rate, arterial blood pressure, pressure distal to the stenosis, and cardiac output did not change significantly during the experiment. Microsphere-determined regional myocardial blood flow was significantly reduced in the left circumflex distribution in the 12 dogs with coronary artery stenoses. In the 12 dogs with left circumflex coronary artery stenoses, the 4 hr fractional Tc-MIBI clearances from the normal and ischemic zones were minimal and equivalent (0.15 +/- 0.05 vs 0.15 +/- 0.07). In the eight control dogs, 4 hr fractional Tc-MIBI clearances from the left anterior descending and left circumflex artery zones were minimal and equivalent (0.11 +/- 0.06 vs 0.10 +/- 0.07). Four hour fractional Tc-MIBI clearance from the blood was 0.98 +/- 0.03 for the dogs with stenosis and 0.97 +/- 0.02 for the dogs without stenosis. One additional dog had complete occlusion of the left circumflex coronary artery followed by administration of Tc-MIBI and scandium-46-labeled microspheres. This heart was immediately sectioned and counted to determine the relationship of regional blood flow to Tc-MIBI distribution (r = .92).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Soluble and Lente human insulin mixtures in normal man.

The interaction between soluble (Actrapid HM) and Lente (Monotard HM) human insulin preparations was examined in normal subjects. Incremental plasma insulin levels were determined following the subcutaneous administration of 6 U of soluble insulin admixed with 0.14 ml soluble insulin diluting medium, or 0.14 ml Lente diluting medium and injected either immediately or 5 min after preparation. For comparison separate but simultaneous injections of soluble (6 U) and Lente insulin (14 U) were administered subcutaneously. All injection volumes were identical. The incremental insulin levels were significantly greater between 60 and 90 min (p less than 0.05-0.01) following the administration of soluble insulin admixed with its own medium compared to the soluble insulin/Lente medium admixtures injected immediately and 5 min after preparation. There was no difference, however, in the plasma insulin profiles between the two soluble insulin/Lente medium schedules. The separate simultaneous administration of soluble and Lente insulin resulted in significantly higher plasma insulin levels at 30 and 90 min (p less than 0.05) when compared to the admixture injected immediately after preparation and from 30-120 min (p less than 0.05-0.01) compared to the admixture injected after 5 min. The two soluble/Lente insulin admixtures achieved similar plasma insulin profiles. Therefore when soluble human insulin is admixed with Lente human insulin and administered by subcutaneous injection immediately after admixing there is a significant reduction in the plasma insulin levels during the first 90 min in contrast to when the two preparations are given simultaneously by separate injection. Delaying the injection of the admixture for 5 min results in significantly lower insulin levels up to 120 min. These differences are reflected in the hypoglycaemic responses observed.

Adult↗
PubMed1988

Retinopathy in newly presenting non-insulin-dependent (type 2) diabetic patients.

One hundred and twenty-nine (97 M, 32 F) previously untreated non-insulin-dependent diabetic patients were studied. Meal and glucose (75 g) tolerance tests were performed on two separate days with glucose, C-peptide and insulin levels estimated during each with the inclusion of growth hormone during the meal test. In addition glycosylated haemoglobin (HbA1) and plasma creatinine levels were determined. Clinical evaluation included detailed ophthalmological examination following mydriasis. Differences between retinopaths (n = 21) and non-retinopaths (n = 108) were FPG 13.7 vs 11.6 (mmol/l) (p less than 0.01); HbA1: 12.9 vs 11.3 (%) (p less than 0.01); BMI: 25.2 vs 29.4 (kg/m2) (p less than 0.001); age 56.8 vs 52.4 (yr) (ns); creatinine: 91.2 vs 88.4 (mumol/l) (ns); systolic blood pressure: 152.4 vs 143.9 mmHg (ns); diastolic blood pressure 87.9 vs 87.7 mmHg (ns); fasting growth hormone: 4.6 +/- 0.9 vs 2.4 +/- 0.3 (mU/1) (p less than 0.01). Multivariate logistic analysis however revealed that systolic blood pressure in conjunction with the insulin response gave the most significant correlation with retinopathy. No significant correlation was observed with age, sex, diastolic blood pressure, creatinine, family history or smoking. The effect of disease duration could not be evaluated. B-cell function appears central to microvascular complications in non-insulin dependent diabetes mellitus.

Blood Glucose↗
PubMed1987

Some family social background, developmental, and behavioural characteristics of nine year old children with asthma.

Children with moderate and severe, mild, and trivial asthma were compared with a group of children who did not have asthma on a range of measures including family social background (socioeconomic status, family adversity, family environment), intelligence, reading, spelling, and behaviour. None of the background measures significantly differentiated among the groups. The group of children with moderate and severe asthma was found to have a significantly lower mean score for verbal intelligence, full scale intelligence, and spelling than those with mild asthma, but did not differ significantly from the remainder of the sample. Children with mild asthma were found to have slightly higher reading scores.

Asthma↗
PubMed1987

Inhibition of von Willebrand factor binding to platelets by two recognition site peptides: the pentadecapeptide of the carboxy terminus of the fibrinogen gamma chain and the tetrapeptide arg-gly-asp-ser.

When platelets are stimulated by thrombin or ADP, von Willebrand factor (vWf) binds to the platelet glycoprotein IIb/IIIa (GPIIb/IIIa). Two recognition sites for vWf binding have been identified on the GPIIb/IIIa. One is a tetrapeptide, arg-gly-asp-ser (RGDS), and the second is a dodecapeptide with the sequence HHLGGAKQAGDV. We used these purified peptides to analyze the recognition specificities for the platelet binding of vWf. The RGDS and the pentadecapeptide totally inhibited 125I-vWf in a dose-dependent manner. The IC50 was 8 microM for the RGDS and 40 microM for the pentadecapeptide. These results indicate that the RGDS binds with higher affinity to a vWf binding site on GPIIb/IIIa than does the pentadecapeptide site. When the two peptides were incubated together, they augmented the inhibition of vWf binding. These data support the evidence that the GPIIb/IIIa has two distinct binding sites for vWf binding. The RGDS site appears to have a higher affinity for the vWf binding site than does the pentadecapeptide site.

Adenosine Diphosphate↗