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Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 577 records · Page 32Linked to original sources
PubMed1990

Primary standardization for the ELISA of serum thyroperoxidase and thyroglobulin antibodies and their prevalence in a normal Welsh population.

This paper describes the use of ELISA techniques, together with university available primary standards, for the assay of the thyroid autoantibodies anti-thyroperoxidase (TPOAb) and anti-thyroglobulin (TgAb). The data obtained using ELISA compared well with that obtained by passive haemagglutination giving correlation coefficients of 0.79 and 0.83 respectively. TPOAb and TgAb concentrations were assayed in serum samples from 832 healthy individuals aged between 18 and 45 years and cut-off values for both antibodies have been defined (TPOAb less than 19.6kIU/l; TgAb less than 98kIU/l). Applying these cut-off values, some 10% of the population showed elevated anti-thyroid antibody activity and, when divided by sex, a majority of this group belonged to the female population.

Adolescent↗
PubMed1989

Is outcome for low risk obstetric patients influenced by parity and intervention?

Maternal and perinatal morbidity were examined to assess the influence of parity and intervention procedures among 1032 women considered low risk at commencement of labour. A diagnosis of fetal distress, failure to progress during labour, maternal problems after delivery and consultation with or transfer of the neonate to a paediatrician occurred more frequently amongst nulliparous women (p less than 0.001). Failure to progress in labour was found to be influenced by parity (primigravida), maternal age (less than 20 years) and also by the use of epidural anaesthetic for pain relief (p less than 0.001). Prevalence of abnormal delivery was found to be influenced by parity (primigravida), failure to progress in labour and diagnosis of fetal distress. The use of epidural anaesthesia for pain relief was also found to increase the rate of abnormal delivery (p less than 0.001). Statistically significant differences occurred between the groups of patients, with patients of private specialists having the highest rates for induction (34%), use of epidural for pain relief (40%) and abnormal delivery (46%).

Adult↗
PubMed1989

Endoscopic sphincterotomy in 1000 consecutive patients.

Between 1983 and 1988, endoscopic sphincterotomy was attempted on 1000 consecutive patients with a clinical diagnosis of bileduct stones in a centre with a policy to establish immediate bileduct drainage for retained stones. Endoscopic cholangiography was successful in 985 patients, of whom 782 had visible stones and 203 had a dilated bileduct but no visible stones. Endoscopic sphincterotomy was successful in 975 of these patients, with eventual bileduct clearance in 674 of 772 patients (87.3%) with visible stones; immediate bileduct drainage was achieved in 160 of the 161 patients (99%) in whom bileduct clearance failed at the first attempt. Overall, 771 of 797 patients (96.7%) with visible bileduct stones had successful bileduct clearance or drainage. Complications occurred in 6.9%, with a 30-day mortality rate of 1.2%, but procedure-related mortality was only 0.6%.

Adult↗
PubMed1989

The glucose dependent insulinotropic polypeptide response to oral glucose and mixed meals is increased in patients with type 2 (non-insulin-dependent) diabetes mellitus.

Considerable disagreement exists regarding the levels of immunoreactive glucose dependent insulinotropic polypeptide in patients with Type 2 (non-insulin-dependent) diabetes mellitus. Glucose dependent insulinotropic polypeptide levels were therefore studied during oral glucose and mixed meal tolerance tests in normal subjects (n = 31) and newly presenting previously untreated patients with Type 2 diabetes mellitus (n = 68). The tests were performed in random order after overnight fasts and blood samples were taken at 30 min intervals for 4 h. During the oral glucose tolerance test plasma glucose dependent insulinotropic polypeptide levels increased in the normal subjects from a fasting value of 20 +/- 3 pmol/l to a peak of 68 +/- 5 pmol/l at 30 min and in the Type 2 diabetic patients from a similar fasting level of 27 +/- 3 pmol/l to a higher peak value of 104 +/- 6 pmol/l at 30 min (p less than 0.001). Glucose dependent insulinotropic polypeptide levels were significantly higher in the diabetic patients compared with the normal subjects from 30-90 min (p less than 0.01-0.001) following oral glucose. During the meal tolerance test glucose dependent insulinotropic polypeptide levels increased in the normal subjects from a pre-prandial value of 22 +/- 4 pmol/l to a peak of 93 +/- 6 pmol/l at 90 min and in the Type 2 diabetic patients from a similar basal level of 25 +/- 2 pmol/l to a higher peak of 133 +/- 7 pmol/l at 60 min. Glucose dependent insulinotropic polypeptide concentrations were significantly higher in Type 2 diabetic patients compared with the normal subjects at 30 min (p less than 0.001), 60 min (p less than 0.01) and from 210-240 min (p less than 0.05) during the meal tolerance test. The groups were subdivided on the basis of degree of obesity and glucose dependent insulinotropic polypeptide concentrations were still higher in the diabetic subgroups compared with the normal subjects matched for weight. Type 2 diabetes mellitus is associated with an exaggerated glucose dependent insulinotropic polypeptide response to oral glucose and mixed meals which is independent of any effect of obesity.

Adult↗
PubMed1989

A comparison of 13-year-old boys with attention deficit and/or reading disorder on neuropsychological measures.

This study compared 13-year-old boys with attention deficit disorder (ADD) and/or reading disability (RD), and controls with neither disorder on a battery of verbal and nonverbal neuropsychological measures. The aim was to examine whether ADD was associated with a qualitatively distinct pattern of deficits compared with RD. None of the measures differentiated the boys with ADD-only from the controls; the only deficit associated with ADD was slightly lower IQ. RD, on the other hand, was associated with deficits in memory and verbal skills.

Adolescent↗
PubMed1989

The structure and correlates of self-reported symptoms in 11-year-old children.

Self-reports of DSM-III symptomatology were obtained from 792 11-year-old children using the Diagnostic Interview Schedule for Children (DISC). We report results concerning 13 subscales derived from the DISC. Factor analysis of the subscales suggested a broad distinction between "externalizing" and "internalizing" disorder for boys' self-report. For girls, two separate internalizing factors representing anxiety and depression emerged. We also found sex differences in correlates of self-reported disorder. Finally, we examined agreement between child and parent and teacher reports. Overall, agreement was relatively low, although somewhat higher for child-parent than for child-teacher.

Achievement↗
PubMed1989

Sensitivity, specificity, and positive predictivity of the Hemoccult test in screening for colorectal cancers. The University of Minnesota's Colon Cancer Control Study.

Data are presented on the sensitivity, specificity, and positive predictivity of the Hemoccult test based on the experience of the Minnesota Colon Cancer Control Study, a randomized clinical trial to determine whether the use of the Hemoccult test can reduce mortality from colorectal cancer. Rehydrating the slides with a drop of water before processing resulted in an increase in positivity (2.4% to 9.8%), and sensitivity (80.8% to 92.2%) but a decrease in specificity (97.7% to 90.4%) and positive predictivity (5.6% to 2.2%). The effects of age and sex were also evaluated. The test was less specific for men than women (p = 0.03). Specificity was highest for those less than 60 yr of age and decreased with increasing age (p = 0.05). The positive predictivity increased with age from 1.6% for those under 60 yr to 3.6% for those over 70 yr (p = 0.0004).

Age Factors↗
PubMed1989

Changes in condyle position after bilateral vertical ramus osteotomy with and without osteosynthesis.

The purpose of the present study was to elucidate the importance of ramal osteosynthesis and evaluate postoperative condylar movements. The right temporomandibular joints of 53 patients with mandibular prognathism were examined by linear tomography the day before, 1 week after, and 1 year after surgery. During surgery the patients were randomly allocated to two groups: one with (n = 26) and one without (n = 27) osteosynthesis. It was found that osteosynthesis did not influence condyle position (p greater than 0.3). The two groups were thereafter pooled. Radiographic measurements of the posterior and anterior interarticular space revealed that condyle position 1 week postoperatively was forward and downward in relation to the preoperative position (posterior fossa, p less than 0.001; anterior fossa, p less than 0.01). One year later the condyle position demonstrated a tendency to approximate the preoperative position, especially with respect to the posterior part, but there was still a significant (p less than 0.01) difference when related to the original position. In conclusion, osteosynthesis after ramus osteotomy seems to be of no importance when healing and postoperative condyle position are considered. Furthermore, 1 year after surgery the condyles were not reestablished in their preoperative positions.

Adolescent↗
PubMed1989

Relationships of changes in craniofacial morphology, head posture, and nasopharyngeal airway size following mandibular osteotomy.

The aim of the present study was to illustrate a possible relationship between changes in craniofacial morphology after mandibular osteotomy and changes in head posture and nasopharyngeal airway size. The material comprised standardized profile cephalograms of 52 patients with mandibular prognathism, all of whom underwent orthodontic adjustment before mandibular osteotomy. Mean age of the patients was 24.3 years; 12 men and 40 women participated in the study. The first profile radiograph of each patient was taken 1 day before surgical treatment in the natural head (mirror) position. All patients underwent mandibular surgery with a bilateral vertical ramus osteotomy. The cephalometric investigation was repeated approximately 1 year after the surgical procedure (means = 1.12 years). Craniofacial morphology was evaluated by 12 parameters describing sagittal and vertical jaw relationship. Head posture was evaluated by the craniocervical angulation and airway as nasopharyngeal airway size. Pearson's correlation analysis was used to evaluate the relationship between morphology, posture, and airway size before surgery and changes in these parameters after surgery. Before surgical treatment statistically significant correlations were found between posture and many morphologic variables, mostly mandibular. Small correlations were observed between posture and airway size, and airway size and morphology. After the surgical procedure, changes in posture were still related to changes in mandibular morphology, while other correlations between posture and morphology had been eliminated. Changes in nasopharyngeal airway size were not correlated to any changes in morphology, apart from maxillary prognathism, nor to changes in posture. The results indicated that mandibular morphology and function play a significant role in determining head posture.

Adolescent↗
PubMed1989

Long-term potentiation of hippocampal mossy fiber synapses is blocked by postsynaptic injection of calcium chelators.

The role of intracellular calcium in an APV-insensitive form of long-term potentiation (LTP) has been studied at the hippocampal mossy fiber synapse. Intracellular calcium was buffered by iontophoretic injection of either BAPTA or QUIN-2, into CA3 pyramidal neurons. The slow calcium-dependent after hyperpolarization was used as an indicator of buffering. LTP was elicited in control and in APV-treated cells (6/6 and 4/5 cell, respectively). In contrast, LTP was observed in only 2/9 BAPTA-loaded cells and in 1/4 QUIN-2-loaded cells. The magnitude of LTP for control and APV-treated cells were not significantly different, but both groups showed significantly greater LTP than BAPTA-loaded cells. These results suggest that an increase in postsynaptic calcium is required for the induction of mossy fiber LTP.

2-Amino-5-phosphonovalerate↗
PubMed1989

Chronic intrastriatal L-pyroglutamate: neuropathology and neuron sparing like Huntington's disease.

Continuous injection of L-pyroglutamate (L-PGA) into the rat striatum induces a lesion with three regions: a necrotic core, a rim of pyknotic cells, and a peripheral spongiose region. The L-PGA was administered through an implanted intrastriatal cannula coupled to an Alzet osmotic pump loaded with one of three doses of L-PGA (3, 5, or 13 times the normal amount of L-PGA/g wet wt rat forebrain (23 nmol/g). The magnitude of the lesion was dependent upon the concentration of buffered L-PGA and the duration of continuous pumping. The necrotic region contained macrophages and neutrophils, while condensed neurons and oligodendroglial cells were present in the pyknotic region. The spongiose region contained vacuolated neuropil and degenerating nerve cells and oligodendroglia. The spongiose region blends with the normal neuropil. A population of aspiny neurons were identified throughout the spongiose region. These neurons stained positive for NADPH diaphorase and demonstrated a somatostatin-like immunoreactivity similar to that of the aspiny neurons spared in Huntington's disease and in the neurotoxin-induced striatal-lesioned rat models of Huntington's disease.

Animals↗
PubMed1989

An evaluation of community antenatal care.

A study to ascertain how the community based antenatal services in the East End of Glasgow related to the guidelines set by a Working Party on Ante-Natal and Intrapartum Care (Royal College of Obstetricians and Gynaecologists, 1982) is reported. All community based clinics were visited and described. The socio-economic status of the sample population was defined and users' views and preferences sought. The women sampled were often socially and economically disadvantaged. Unemployment was high. They received their community antenatal care from midwives, general practitioners and consultants in both health centres and general practitioner surgeries. Women were generally satisfied with the care they received. Answers to more specific questions indicated, however, that more information and individualised care would be appreciated.

Adult↗
PubMed1989

Structural alterations of the RB1 gene in human soft tissue tumours.

Sixty-nine primary soft tissue tumours were examined for alterations of the RB1 gene which has previously been implicated in the genesis of retinoblastoma. In three tumours loss of both alleles of this gene (homozygous deletion) was detected. Two of these, both leiomyosarcomas, contained a chromosomal breakpoint within the RB1 gene, while in the third tumour, a radiation induced sarcoma, complete deletion was observed. Using a probe that detects a polymorphic locus within the RB1 gene we found loss of only one allele (heterozygous deletion) in 33% of soft tissue sarcomas examined, including two leiomyosarcomas, a malignant peripheral nerve sheath tumour, a rhabdomyosarcoma and a chondrosarcoma. When taken together our results suggest that alterations of the RB1 locus may play an important part in the pathogenesis of soft tissue tumours and particularly in leiomyosarcomas which accounted for four of the eight RB1 alterations observed in this study.

Alleles↗
PubMed1989

CpG island clones from a deletion encompassing the gene for adenomatous polyposis coli.

Adenomatous polyposis coli (APC), a dominantly inherited disorder, has been mapped to chromosome 5q15-q21 by family linkage studies. Cells from patients with deletions in this region, in one case associated with polyposis in a family, have been used to construct human hamster hybrid cell lines that retain either the normal or deleted chromosome 5. These lines have been used to identify markers from the region of the polyposis gene obtained by cloning the ends of 0.5- to 2-megabase BssHII fragments purified by pulsed-field gel electrophoresis. Three markers are described that map within the deletions and must therefore be close to the APC gene.

Adenoma↗
PubMed1989

Isolation of a complementary DNA encoding a chitinase with structural homology to a bifunctional lysozyme/chitinase.

An extracellular, acidic chitinase was purified to homogeneity from tobacco necrosis virus-infected leaves of Cucumis sativis. The amino acid sequences of the intact protein and of peptides isolated following endoproteinase Lys-C digestion, cyanogen bromide cleavage, and trypsin digestion were determined. Oligonucleotide probes derived from this sequence were used to isolate a cDNA clone encoding this protein. No significant homology was found between this chitinase and either the basic chitinase isolated from bean or tobacco or the chitinase isolated from Serratia marcescens; however, strong homology was found between the cucumber chitinase and a lysozyme/chitinase from Parthenocissus quinquifolia. The induction of the protein by tobacco necrosis virus infection or salicylate was found to be at the level of RNA accumulation. Genomic Southern analysis indicates that a single gene in the cucumber genome encodes this protein.

Amino Acid Sequence↗