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Biomedical subjects

D M Williams

Publications and source records attributed to D M Williams.

At least 217 records · Page 12Linked to original sources
PubMed1990

Enamel defects in the primary dentition of children born weighing less than 2000 g.

The findings for enamel defects in the primary dentition of a group of low birthweight (LBW) children were related to their perinatal medical histories. Examination of 110 LBW children and 93 control children aged 5 years showed that significantly more of the LBW children (71%) had hypoplasia than controls (15%), but there was no difference in opacities alone (LBW 25%, control 26%). In the LBW group, defects were seen more often in children classified as ill during the perinatal period, who received ventilator support or intravenous alimentation and in those children born at less than 32 weeks gestation, compared to the LBW children without these perinatal problems. It is speculated that the high incidence and the cause of enamel defects in sick preterm infants may be due to oxygen deprivation and mineral substitute depletion.

Analysis of Variance↗
PubMed1990

Effects of Bacteroides gingivalis culture products on human polymorphonuclear leucocyte morphology.

This study aimed to determine whether leucocytes exposed to Bacteroides gingivalis culture supernatant exhibited consistent morphological changes and whether measurement of such changes could provide a simple screening assay for bacterial products with potential biological activity. Glass-adherent polymorphonuclear leucocytes were obtained from clotted blood preparations and from blood after purification by centrifugation through Ficoll-Hypaque. These were then incubated in Hanks' balanced salt solution, a sterile liquid medium (BM) and B. gingivalis (W83) culture supernatant. Polymorphonuclear leucocytes were classified by their shape into small non-polar (less than 18 microns diameter), large non-polar (greater than or equal to 18 microns diameter), bipolar and hyperpolar types. Treatment with B. gingivalis culture supernatant consistently increased large non-polar cells by 150% to over 300% (p less than 0.01), when compared with polymorphonuclear leucocytes incubated with the sterile liquid medium (control). This change was accompanied by smaller decreases in small non-polar, bipolar and hyperpolar cells, these being significant for bipolar cells in clot preparations (p less than 0.01) and small non-polar cells after Ficoll-Hypaque isolation (p less than 0.01). Neither the liquid medium nor the B. gingivalis culture supernatant was toxic to the cells as indicated by trypan blue exclusion tests. Lipopolysaccharide and short-chain fatty acids were not responsible for the changes in polymorphonuclear leucocyte shape. However, the activity of the culture supernatant was destroyed by heating at 80 degrees C for 30 min, indicating that proteolytic enzymes may have been involved.

Bacteriological Techniques↗
PubMed1990

Tumor necrosis factor-alpha plays a role in host defense against Histoplasma capsulatum.

Tumor necrosis factor-alpha was detected in supernatants collected from BALB/c mouse peritoneal macrophages incubated continuously with Histoplasma capsulatum. The levels of TNF alpha measured by actinomycin D bioassay peaked within hours after exposure and then greatly declined by 24 h. TNF alpha was also measured in bronchoalveolar lavage fluid from BALB/c mice challenged intranasally with H. capsulatum. Lavage fluid TNF alpha levels exhibited the same pattern as the in vitro supernatants; they peaked within hours after challenge and lower levels were detected at 24 h. Treatment of mice with anti-TNF alpha antibody accelerated mortality in response to systemic infection and significantly increased tissue colony counts in the liver and spleen. In the murine model, TNF alpha is produced in response to H. capsulatum and appears to play some role in host defense to infection.

Animals↗
PubMed1990

A comparison of the preoperative concerns of open heart surgery patients and their significant others.

This article reports the findings of research about the concerns of open heart surgery (OHS) patients and their significant others (SOs) during the preoperative in-hospital waiting period. Concepts from the Roy Adaptation Model for Nursing framed this study and provided a basis for recognizing the problem, constructing instruments to measure the variable, analyzing and interpreting the data, and drawing implications from the findings. A convenience sample of 21 pairs of OHS and SO subjects reported data while awaiting surgery about demographic characteristics and concerns on self-administered instruments constructed for this research. A multitude of concerns was reported by the subjects, with some similarities and some differences between the OHS patients and their SOs. Implications for practice and theory are drawn, and suggestions for research are made.

Adaptation, Psychological↗
PubMed1990

Vesiculo-bullous mucocutaneous disease: benign mucous membrane and bullous pemphigoid.

Bullous pemphigoid (BP) and benign mucous membrane pemphigoid (BMMP) are autoimmune diseases characterised by subepithelial bulla formation and showing substantial overlap in clinical signs and symptoms. BP principally involves skin and BMMP the oral mucosa and eyes. The gingiva are affected in 90% of cases of BMMP and buccal mucosa and palate in up to 30%. Lesions may heal with scarring. Extension into the pharynx and esophagus causes sore throat and dysphagia. Severe ocular involvement may cause blindness. Bulla formation is attributed to complement activation, following IgG binding to the basement membrane zone, with subsequent polymorphonuclear leukocyte accumulation. The target antigen in BP is a 180-230 kD protein associated with the basilar membrane of basal keratinocytes. The gene encoding the BP antigen has been partially cloned. It is likely that the same antigen is involved in BMMP, but the mechanism of scarring is not understood. Treatment of BP and BMMP includes systemic steroid and azathioprine therapy and topical steroids.

Autoimmune Diseases↗
PubMed1990

Quantification of plasma cells in labial salivary glands: increased expression of IgM in Sjögren's syndrome.

Plasma cells expressing IgG, IgA and IgM were quantified in labial salivary glands from patients with Sjögren's syndrome (SS) and compared with glands showing non-specific inflammatory changes and normal controls. In all glands the predominant isotype was IgA but in SS there was a significant increase in both the number and proportions of IgG and IgM positive cells (P less than 0.002). In particular, all SS cases contained greater than 10% IgM positive cells (mean = 26.8 +/- 15.5). The results suggest that accumulation of IgM positive plasma cells may be a specific finding in SS and support the concept that the glandular lesions may be a site of B-cell clonal expansion. Since most B-cell hyperproliferative states in SS, including lymphoma, are associated with synthesis of IgM simple quantification of plasma cells may have important diagnostic and prognostic significance.

Adolescent↗
PubMed1990

In vivo effects of Candida albicans products on rat oral epithelium.

Candida albicans has been associated with epithelial hyperplasia in some diseases of oral mucosa and skin but its etiologic role in these lesions is poorly understood. To test its ability to induce epithelial proliferation, the invasive hyphal form was cultured for 5 h and 23 h in chemically defined medium and yeast-free culture supernatants were injected below the buccal epithelium of young adult Sprague Dawley rats. The mitotic activity was assessed using the metaphase arrest technique 11 h and 31 h after supernatant injection. There was a significant increase in epithelial mitotic activity 31 h after injection with 5 h culture supernatants compared to control media indicating that the supernatants have an effect on epithelial cells, possibly by direct action on them.

Animals↗
PubMed1990

A role in vivo for tumor necrosis factor alpha in host defense against Chlamydia trachomatis.

In a mouse model of pneumonia caused by murine Chlamydia trachomatis (mouse pneumonitis agent [MoPn]), tumor necrosis factor alpha (TNF-alpha) antigen and bioactivity were demonstrated in vivo in the lung during MoPn infection in both athymic (nude) and heterozygous (nu/+) mice. Antibody to TNF-alpha that was exogenously given neutralized the TNF-alpha in the lung, significantly accelerated mortality, and caused a borderline increase in MoPn counts in the lung by culture in nu/+ mice. Lipopolysaccharide-induced TNF-alpha activity or injections of recombinant murine TNF-alpha significantly but modestly protected nu/+ mice against MoPn-induced mortality. TNF-alpha is produced in vivo during C. trachomatis infection and plays a role in host defense.

Animals↗
PubMed1990

Hyperinsulinaemic hypoglycaemia in small for dates babies.

Blood glucose concentrations were measured prospectively in 27 small for dates infants in the first 48 hours after birth: 10 infants became hypoglycaemic. Of these, five had inappropriately raised plasma insulin concentrations. Plasma free fatty acids were lower and carbohydrate intake higher in these five infants, further supporting the diagnosis of hyperinsulinism. The hypoglycaemia recurred in four of the five hyperinsulinaemic infants, but in none of those who were not hyperinsulinaemic. Hyperinsulinism is common in small for dates babies. It is important to recognise this because hypoglycaemia is likely to recur and appropriate treatment is needed to prevent long term sequelae.

C-Peptide↗
PubMed1990

Relief of mesenteric ischemia in type III aortic dissection with percutaneous fenestration of the aortic septum.

Subacute mesenteric ischemia developed 2 months after initial presentation in a patient with a type III aortic dissection. Percutaneous transfemoral fenestration of the septum between the true and false lumens resulted in resolution of clinical, angiographic, and manometric signs of ischemia. Continued expansion of the false lumen required aortic resection and graft replacement of the distal thoracic and abdominal aorta 2 months after the fenestration procedure. At operation, the fenestration site appeared as a 2-cm horizontal tear in the aortic septum, free of adherent thrombus and unrelated to expansion of the false lumen.

Aortic Dissection↗
PubMed1990

CT-angiographic correlation of collateral venous pathways in isolated splenic vein occlusion: new observations.

The computed tomographic (CT) findings in 18 patients with angiographically proved, isolated splenic vein occlusion (SVO) were retrospectively analyzed. The distribution of venous collateral vessels and the frequency of their occurrence in these patients were then compared with CT findings in 17 patients with proved portal hypertension and normal CT findings in 20 patients. Short gastric and coronary collateral vessels were seen in 61% and 83%, respectively, of patients with SVO and in 71% each in patients with portal hypertension. However, a large gastroepiploic vein was seen only in patients with SVO (11 of 18 patients [61%]). Recanalization of umbilical/paraumbilical veins was seen only in patients with portal hypertension (seven of 17 patients [41%]). Results suggest that collateral vessels in SVO often have a characteristic and distinctive appearance on abdominal CT scans.

Adult↗
PubMed1990

Peripheral arterial occlusive disease: P-31 MR spectroscopy of calf muscle.

The effect of a graded exercise protocol on phosphorus-31 magnetic resonance (MR) spectroscopy of calf skeletal muscle in nine healthy (control) subjects and 16 patients with symptomatic peripheral arterial occlusive disease (PAOD) was assessed. Ankle-brachial pressure indexes were obtained in all 16 patients, and 10 patients underwent peripheral arteriography. Temporal profiles of pH and the inorganic phosphorus (Pi) index were calculated from the spectra. A Pi-index recovery rate constant was calculated for each subject. Arteriograms were graded by calculating the runoff resistance in the limb of interest. The pH profiles during exercise did not differ significantly between the PAOD patients and control subjects. The Pi-index recovery rate constant in the PAOD patients was significantly (P less than .01) smaller than in the control subjects. There was no significant correlation between recovery rate and the ankle-brachial pressure indexes, but there was a strong negative correlation between recovery rates and angiographic resistance grades, with smaller recovery rate constants in patients with increased arterial resistance. It is concluded that P-31 MR spectroscopy shows promise as a direct measure of tissue perfusion.

Adult↗
PubMed1990

Phenylpropanolamine hydrochloride.

Phenylpropanolamine has been classified by the FDA advisory review panel as generally safe and effective for short-term weight control. The maximum daily dose for this indication is 75 mg. When used in recommended doses by patients without significant risk factors, serious side effects appear to occur infrequently. The pharmacist has an important role in preventing misuse and abuse of phenylpropanolamine through counseling the patient about its appropriate, short-term (not exceeding 12 weeks) use in a comprehensive weight-reduction program. Patients should be alerted to signs and symptoms of serious adverse reactions and advised to discontinue use if any reactions appear.

Appetite Depressants↗
PubMed1990

Training of native technicians in audiological techniques in northern Ontario: an update.

A native audiological technician is performing a useful service in the James Bay area. Major shortcomings in data gathering and supervision are being addressed, so that we may monitor quantity and quality of work more closely. Audiological supervision is considered to be particularly important, and has been upgraded. Telecommunication is being installed in the near future, and clerical assistance for the technician introduced.

Adolescent↗