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Biomedical subjects

S M Williams

Publications and source records attributed to S M Williams.

At least 163 records · Page 9Linked to original sources
PubMed1989

Postneonatal mortality in south New Zealand: necropsy data review.

Three southern New Zealand health districts had a postneonatal mortality rate of 8.1 per 1000 livebirths and a postneonatal sudden infant death syndrome (SIDS) mortality rate of 6.3 per 1000 livebirths for the period 1979-1984. This is one of the highest reported rates of SIDS. The 429 postneonatal deaths occurring during the period were assigned to one of four groups: unpreventable (n = 52), possibly preventable non-SIDS (n = 45), SIDS with minor abnormalities at necropsy or premorbid symptoms (n = 167), and SIDS with no abnormalities at necropsy or documented premorbid symptoms (n = 165). These groups were related to obstetric and perinatal data. For those infants classified as SIDS, the winter peak of deaths was particularly marked if death occurred after 3 months of age. These older SIDS deaths had more minor abnormalities at necropsy, a longer interval between time last seen or heard alive and found dead and more thymic petechiae.

Cause of Death↗
PubMed1989

Computed tomography and magnetic resonance imaging of cervical metastasis.

Thirteen patients with head and neck cancer underwent staging by clinical examination, computed tomography (CT), and magnetic resonance imaging (MRI) in a standardized blinded fashion. All patients subsequently underwent radical neck dissection with subsequent pathologic staging. CT and MRI each predicted 93% of staging results correctly, with clinical examination correct 67% of the time. Staging of primary tumors had an accuracy of 90% by clinical examination, 40% by CT, and 50% by MRI when compared to staging the pathologic specimen. Understaging was seen in 50% of CT scans and 30% of MRI scans. We believe either CT or MRI should be considered for routine staging of the neck in all head and neck malignancies.

Aged↗
PubMed1989

Recall of injury events by thirteen year olds.

The level of under-reporting of injury events which resulted in medical treatment was determined for a group of 631 thirteen-year olds. Two-year recall data was compared with the medical records of an accident and emergency department. Thirty-nine percent of all visits to the accident and emergency department were not recalled. Recall was shown to be related to the number of injury events, time elapsed since an injury event, type and severity of injury but not to whether the victim was hospitalized. Logistic regression analysis suggested that the recall of injury events depended on the type of injury sustained, time elapsed since the injury event, the number of injury events, and an interaction effect between the time and the number of injuries.

Adolescent↗
PubMed1988

Plasmids in coryneform bacteria of human origin.

A study of plasmids in coryneform bacteria isolated from human sources is reported. Seventy of 269 strains possessed a total of 89 plasmids. These were shown to be of varying sizes and in some cases of varying structures by endonuclease restriction digest. In six of 20 strains antibiotic resistance was cured with loss of the plasmid. The diversity of plasmids is emphasized.

Actinomycetales↗
PubMed1988

Refractive error, IQ and reading ability: a longitudinal study from age seven to 11.

Children from a population sample whose cycloplegic refractive errors included myopia, pre-myopia and hypermetropia were compared on measures of IQ and reading with a group of children without significance refractive errors. At age 11 both those with myopia and with pre-myopia had increased verbal and performance IQ, while those with hypermetropia had slightly reduced verbal and performance IQ, in comparison with the children without refractive errors. The differences in verbal IQ were not attributable simply to earlier differences, but the differences in performance IQ were attributable to earlier differences. No significant differences in reading scores were found at either age. It is concluded that differing abilities of myopic and other children at age 11 are not fully explained by differences in family background or in pre-existing ability.

Child↗
PubMed1988

Absence of psychosocial bias in the under-reporting of unintentional childhood injuries.

Bias resulting from under-reporting has been largely ignored by studies that have examined the relationships between psychosocial factors and unintentional childhood injuries. This study was part of a larger investigation that examined associations between psychosocial factors and unintentional childhood injuries in a sample of 781 children. Visits to an accident and emergency department and their general practitioners were used to determine whether the children or their mothers were under-reporters. "Under-reporters" were compared with "reporters" on a variety of family, behavioural, and development factors. The analyses showed that under-reporters did not differ significantly from the remainder of the sample in terms of psychosocial factors central to the main study.

Accidents, Home↗
PubMed1988

The need to supplement clinical with experimental-normal studies of hemispheric asymmetry.

It is argued that in spite of the methodological and interpretive problems with them, experiments on laterality in normal subjects must continue in view of other problems with direct neuroclinical investigations. A variety of such problems are listed, ranging from the relative paucity of the potential subject population to the difficulty in inferring normal function from damaged brains. The main justification for such studies must be the possible amelioration of the lot of brain-damaged patients and improvement of their treatment rather than scientific curiosity.

Brain Damage, Chronic↗
PubMed1987

Differences in life history traits between alcohol dehydrogenase genotypes of Drosophila mercatorum: background and maternal genotype effects.

The effects of genotype at the alcohol dehydrogenase (ADH) locus on developmental time and fecundity were studied using three strains of Drosophila mercatorum. All three strains had similar genetic backgrounds and two were homozygous for the same electrophoretic allele (F for fast). The third strain was homozygous for the slow allele (S). The life history traits of all possible progeny of these strains were studied. The results showed that for both mean developmental time and pattern of eclosion, strong maternal genotype and background effects were present. Fecundity among genotypes was not different, although there was an effect on the total number of offspring suggesting differences in egg-to-adult survivorship.

Alcohol Dehydrogenase↗
PubMed1987

Cycling experiences and knowledge of the road code of nine-year-olds.

Sex differences in cycling experience and knowledge of the road code were examined in a sample of eight-hundred and fifteen nine-year-old children. The results showed that there were not significant sex differences for those who had ridden on the road or ridden to school in the week preceding the interview. However, males were more likely to have ridden at night. There were no significant sex differences in self reported unsafe acts or in knowledge of various dimensions of the road code. The results show a relatively high level of ignorance of the give-way rules for uncontrolled intersections and a disturbing number of children who reported they had ridden at night without tail or headlights.

Accidents, Traffic↗
PubMed1987

Chloroplast DNA polymorphisms in lodgepole and jack pines and their hybrids.

Samples taken from throughout the ranges of distribution of lodgepole pine (Pinus contorta Dougl. ex. Loud.) and jack pine (Pinus banksiana Lamb.) were assayed for Sal I and Sst I chloroplast DNA restriction fragment variation. Although the chloroplast genome is often regarded as highly conserved, at least 2 distinct Sal I and 13 distinct Sst I restriction fragment banding patterns occur in these closely related species. None of the chloroplast DNA restriction fragment banding patterns observed in allopatric lodgepole pine was observed in allopatric populations of jack pine, and vice versa, even though the two species share an extensive zone of sympatry, and gene flow between the species has been reported for nuclear genes. However, several atypical Sst I restriction fragment banding patterns occur only in or near the zone of sympatry. Chloroplasts have been reported to be inherited maternally in the great majority of species studied; however, restriction fragment analyses indicated that chloroplasts are inherited paternally in controlled matings between lodgepole pine (female) and jack pine (male).

Canada↗
PubMed1987

Differences in academic performance at school depending on handedness: matter for neuropathology?

Two studies found that left-handed children had significantly poorer academic records than did right-handed children, though the effect was small. Study 1 provided evidence that, for some academic disciplines, the important difference appeared to be between those children whose family history of handedness was concordant with their own handedness and those children whose family history of handedness was discordant with their own handedness. The inclusion of gender in asymmetry research was bolstered by Study 2. When predicting idiosyncrasies in left-handers' cognitive performance, it should be borne in mind that left-handers form a minority group as well as a neurologically distinct one.

Achievement↗
PubMed1987

Evolution of the ribosomal DNA spacers of Drosophila melanogaster: different patterns of variation on X and Y chromosomes.

Length variation of the ribosomal gene spacers of Drosophila melanogaster was studied. Analysis of 47 X chromosomal and 47 Y chromosomal linked rDNA arrays collected from five continents indicates that the arrays on the two chromosomes differ qualitatively. The Y-linked arrays from around the world share little or no similarity for either their overall length or the organization of their spacers. Most of the X-linked arrays do, however, share a major length spacer of 5.1 kb. In addition, those X-linked arrays that have a major 5.1-kb band have similar spacer organization as demonstrated by genomic DNA digestions with several restriction enzymes. These data strongly support the hypothesis that spacer length patterns on only X-linked genes are maintained primarily by natural selection.

Animals↗
PubMed1987

Mucocutaneous and peripheral soft-tissue hemangiomas: MR imaging.

Hemangiomas are common congenital lesions that may have devastating sequelae. The extent and location of a lesion determines the therapeutic approach. We describe 11 patients with mucocutaneous or peripheral soft-tissue hemangiomas to illustrate the ability of magnetic resonance (MR) imaging to define clearly and noninvasively the extent and anatomic relationships of hemangiomas. The major advantage of MR imaging over computed tomography or angiography is the exquisite difference in contrast between hemangiomas and the surrounding structures on T2-weighted MR images, in which hemangiomas have a relatively intense signal. Hemangiomas demonstrated relatively low signal intensity (similar to muscle) on T1-weighted images, which were markedly inferior to T2-weighted images in defining the extent of the lesions. Phleboliths and feeding or draining vessels were rarely visible. The information obtained with MR imaging may be valuable clinically in planning surgical resection or laser therapy of aggressive lesions, in evaluating effectiveness of medical or embolic therapy, and in defining recurrence.

Adult↗
PubMed1987

The normal temporomandibular joint: MR and arthrographic correlation.

Magnetic resonance (MR) images of 28 normal temporomandibular joints were obtained and correlated with respective arthrograms. There was a spectrum in the configuration and thickness of normal articular menisci. The anterior band varied from thin with a flat inferior margin to thick with a bulbous, convex inferior margin. The anatomic configuration of the meniscus as seen with MR correlated directly with normal variations of the anterior recess seen with arthrography. Concavity of the superior aspect of the anterior recess as seen on arthrography was caused by a thick, bulbous anterior band of the meniscus, whereas a flat anterior recess resulted from a thin anterior band without a convex inferior margin. This study emphasizes that the appearance of a concave anterior recess on static arthrograms is not necessarily due to a displaced meniscus.

Adult↗
PubMed1987

Arachidonic acid metabolites in the pathophysiology of thrombocytopenia and haemorrhage in acute African swine fever.

Changes in the production of proaggregatory (thromboxane A2 and prostaglandin E2) and antiaggregatory (prostacyclin) prostaglandins by blood platelets, macrophages and endothelial cells during acute African swine fever caused by both a highly virulent virus and a less virulent virus were studied. No impairment in thromboxane A2 release by either platelets or macrophages could be detected but prostacyclin production by the endothelium was impaired. There was also a significant increase in prostaglandin E2 release by macrophages at the time when thrombocytopenia was most marked. However, the early event that causes primary aggregation remains obscure.

African Swine Fever↗
PubMed1987

Hepatobiliary complications of inflammatory bowel disease.

A variety of biliary and hepatocellular diseases occur with increased incidence in patients with inflammatory bowel disease. These include fatty infiltration of the liver, cholelithiasis, pericholangitis-primary sclerosing cholangitis, cirrhosis, chronic active hepatitis, liver abscess, amyloidosis, granulomatous hepatitis, and bile duct carcinoma. Radiography is essential in accurate diagnosis.

Adult↗