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Biomedical subjects

D Wilson

Publications and source records attributed to D Wilson.

At least 235 records · Page 13Linked to original sources
PubMed1995

Thyroiditis in the BB rat is associated with lymphopenia but occurs independently of diabetes.

The spontaneously diabetic BB rat is an excellent and well studied model for human insulin-dependent diabetes (IDDM), sharing many important features with the human disease. Similarities include an equal frequency of IDDM in males and females, production of antibodies against pancreatic cell antigens, and an MHC disease association. In addition, the BB rat shares with human IDDM patients an increased frequency of autoantibodies against the parietal cells of the stomach and colloid cells of the thyroid gland. Here we investigate the genetic basis of thyroiditis in the BB rat. Based on crosses between BB, Lewis and Fischer rats, we show that two susceptibility factors for diabetes--the lymphopenia trait present in diabetes prone BB rats and the MHC--also appear to be risk factors for thyroiditis. However, the nature of the susceptibility was different for the two autoimmune diseases, with lymphopenia being absolutely required for diabetes although it only conferred increased risk for thyroiditis. Also, in contrast to IDDM, the MHC conferred dominant susceptibility to thyroiditis. Despite these shared risk factors, diabetes per se did not show significant correlation with thyroiditis.

Animals↗
PubMed1995

Isolation of a gene encoding an integral membrane protein from the vicinity of a balanced translocation breakpoint associated with DiGeorge syndrome.

Deletions within 22q11 have been associated with a wide variety of birth defects embraced by the acronym CATCH22 and including the DiGeorge syndrome, Shprintzen syndrome (velocardiofacial syndrome) and congenital heart disease. It is not known how many genes contribute to this phenotype. Previous studies have shown that a balanced translocation disrupts sequences within the shortest region of deletion overlap for DiGeorge syndrome. A P1 clone was isolated which spans this breakpoint and used to isolate a cDNA encoding a transmembrane protein expressed in a wide variety of tissues. This gene (called IDD) is not disrupted by the translocation, but maps within 10 kb of the breakpoint. Mutation analysis of five affected cases with no previously identified chromosome 22 deletion was negative, but a potential protein polymorphism was discovered. No deletions or rearrangements were detected in these patients following analysis with markers closely flanking the breakpoint, data which emphasize that large (i.e. over 1 Mb) interstitial deletions are the rule in DiGeorge syndrome. The proximity of IDD to the balanced translocation breakpoint and its position within the shortest region of deletion overlap indicate that this gene may have a role, along with other genes, in the CATCH22 haploinsufficiency syndromes.

Amino Acid Sequence↗
PubMed1995

The statistical power of [15O]-water PET activation studies of cognitive processes.

[15O]-Water positron emission tomography (PET) scanning is an important means of investigating the neural correlates of cognitive processes. This study analyses the statistical power of these experiments under usual experimental conditions. Eleven subjects were scanned repeatedly while they undertook an active-baseline task. Using an empirically derived estimate of variance, the statistical power to detect task-induced increases in regional cerebral blood flow was calculated for different values of magnitude of change, number of subjects and probability of Type I error. The results (a) provide an empirical basis for selecting the number of subjects for cognitive studies using [15O]-water PET; (b) illustrate the importance of considering the statistical power of the test, while making a physiological interpretation of the results; and (c) highlight the problems in concluding the non-involvement of a given brain region in a cognitive task, based solely on the results of a PET study.

Adult↗
PubMed1995

The safety and efficacy of low-dose tissue plasminogen activator in the treatment of systemic sclerosis.

The safety and efficacy of low-dose (10 mg) recombinant human tissue plasminogen activator (rhtPA: Activase: Genentech) was studied in 14 systemic sclerosis (SSc) patients. The patients were enrolled in a double blind, placebo-controlled crossover trial. Patients who met the inclusion criteria were enrolled in the study, given placebo or rhtPA, and then crossed over at 3 months. Assessment criteria included the Rodnan skin score; a daily patient diary to record side-effects, frequency, and severity of Raynaud's episodes and activity; and pulmonary function tests. Ten mg of rhtPA (Genentech) was administered over a 4 hour period using a myocardial infarction protocol. None of the patients experienced side-effects from the treatment protocol. No differences in the frequency or severity of Raynaud's episodes were noted during the two arms of the study. However, when the mean change of the Rodnan skin score in the placebo arm was compared to the rhtPA arm of the protocol, a significant difference was observed (0.8 vs. -5.4, p < 0.001). Three patients had moderate improvement and seven showed mild improvement. Mild deterioration or no change in study parameters was noted in 4 patients. This study has demonstrated that the administration of low-dose rhtPA is safe and is accompanied by modest improvement in symptoms of a subset of scleroderma patients.

Adult↗
PubMed1995

Smoking-related beliefs and behaviour among adults with asthma in a representative population sample.

BACKGROUND: Smoking and exposure to environmental tobacco smoke are inadvisable for adults with asthma. AIMS: To determine the smoking prevalence and daily smoking rate of asthmatics and compare smoking-related beliefs and behaviours among smokers with and without asthma. To compare beliefs of asthmatics about passive smoking and asthma, how many are exposed at home and what they do when they are exposed, with people who do not have asthma. METHODS: A representative population survey of 3019 South Australian adults aged 15 years and older interviewed in their own homes in late 1992. RESULTS: Twenty-eight per cent of asthmatics were smokers; mean daily smoking rate was 17.6. Asthmatics had similar patterns of smoking, readiness to quit and quit attempt histories as people without asthma. More than 40% of smokers with asthma did not perceive that smoking had greatly affected their health, over half did not believe they were at risk in future and two-thirds did not think future health problems would be serious. Among non-smokers, despite being more convinced of the effects of passive smoking on asthma, and being more concerned about exposure, those with asthma were no more likely to take protective action in response to actual or imminent exposure than those without asthma. One in ten non-smokers with asthma were exposed to smoking at home. CONCLUSIONS: The smoking habits of adults with asthma are cause for concern, with many asthmatic smokers perceiving they are not personally at risk from their smoking. Health education principles should be used by health professionals caring for asthmatic smokers to guide the selection and delivery of smoking cessation strategies. Prevailing restrictions on indoor smoking play an important role in protecting the respiratory health of non-smokers with asthma.

Adolescent↗
PubMed1995

Colorectal cancer and its prevention: prevalence of beliefs, attitudes, intentions and behaviour.

There is so far only limited evidence from randomised controlled trials that screening for colorectal cancer using the faecal occult blood test produces significant mortality reductions in screened groups, but there is considerable activity and interest in the use of such screening in Australia. Beliefs, attitudes, intentions and behaviour in relation to colorectal cancer and screening were examined among participants 40 years and older (n = 1776) who took part in a representative population survey. While there were high levels of awareness of faecal occult blood test screening, most respondents had not had a test, nor did they intend to take a test in the future. Important determinants of participation in screening were a family history of colorectal cancer, a belief that bowel cancer can be cured if detected at an early stage, a perception of personal susceptibility to bowel cancer and an acceptance of the technique. Factors such as these are likely to influence the success of any future screening program in Australia.

Adult↗
PubMed1995

Smoking-related beliefs and behaviour of South Australians with diabetes.

Data cumulated from three representative population surveys (n = 9402) in South Australia were used to determine smoking prevalence of those aged 15 years or over with and without self-reported medically confirmed diabetes. Overall, smoking prevalence in the two groups did not differ. However, among those aged under 40 years with self-reported diabetes, smoking prevalence approached 55 per cent, which was significantly higher than in young respondents without diabetes (32 per cent). Diabetic smokers were no more likely than were nondiabetic smokers to have tried to quit or to be ready to quit; one-quarter of diabetic smokers had no thought of quitting or of modifying their habit. Smokers with diabetes were significantly more likely to be heavy smokers (43.5 per cent) than were nondiabetic smokers (23.4 per cent). Fewer smokers with diabetes tended to believe that smoking causes or aggravates heart disease or circulatory problems than did other smokers, although these differences did not reach statistical significance. Additional effort is required to find methods to assist people with diabetes to refrain from smoking.

Adolescent↗
PubMed1995

Technical note: identifying and aspirating hip effusions.

Ultrasound has become a routine investigation in the investigation of the painful hip in children. It has been recommended that all effusions demonstrated by sonography be drained. Based on the experience of 800 hip aspirations, the authors describe an approach to the demonstration and aspiration of hip effusions with some of the pitfalls that result in false positive and false negative diagnoses.

Adolescent↗
PubMed1995

Spectral changes in metal halide and high-pressure sodium lamps equipped with electronic dimming.

Electronic dimming of high-intensity discharge lamps offers control of photosynthetic photon flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W metal halide (MH) and high-pressure sodium (HPS) lamps were equipped with a dimmer system using silicon-controlled rectifiers (SCR) as high-speed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to HPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and the 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another smaller peak at 545 nm. As input power to the MH lamps decreased, the peak at 589 diminished to equal the 545-nm peak. As input power approached 428 W, the 589-nm peak shifted to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (Pfr : Ptot) remains unchanged for both lamp types.

Dose-Response Relationship, Radiation↗
PubMed1995

Proton MR spectroscopy in patients with neurofibromatosis type 1: evaluation of hamartomas and clinical correlation.

PURPOSE: To use proton MR spectroscopy in patients with neurofibromatosis type 1 to determine: (a) the spectroscopic characteristics of hamartomas and compare them with that of gliomas; (b) whether differences exist between patients with and without learning disabilities; and (c) spectroscopic patterns in normal-appearing brain (by MR imaging) in patients with and without focal lesions. METHODS: Seventeen proton MR spectroscopy volumes were obtained in 10 patients with neurofibromatosis type 1 (including hamartomas, N = 7; normal-appearing brain, N = 10). Seven patients had learning disorders, and 3 were mentally normal. Ten healthy volunteers and 10 patients with pathologically proved gliomas (all grades) were also examined. N-Acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were calculated for all samples. RESULTS: (a) Hamartomas showed higher N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios than gliomas. Hamartomas showed N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios similar to those of healthy volunteers. (b) No significant differences in N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were found in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were similar for patients who had neurofibromatosis type 1 with and without focal hamartomas and in healthy volunteers. CONCLUSIONS: (a) Hamartomas have a proton MR spectroscopy pattern different from that of glioma and similar to that of normal brain. (b) As performed in this study, proton MR spectroscopy did not show significant differences in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) Patients who have neurofibromatosis type 1 with and without hamartomas seem to have normal intervening brain by proton MR spectroscopy when compared with healthy volunteers.

Adolescent↗
PubMed1995

Antibodies to fibrin bound tissue type plasminogen activator in systemic sclerosis.

OBJECTIVE: Abnormalities of tissue type plasminogen activator (tPA) and plasminogen activator inhibitor have been described in some patients with systemic sclerosis (SSc). We studied 128 unselected SSc sera for the presence of autoantibodies to fibrin bound tPA. METHODS: A solid phase fibrin-tPA immunoassay utilized 500 IU/ml tPA bound to solid phase fibrin. Sera diluted 1/50 were incubated with the fibrin bound tPA, the plates were washed, and bound immunoglobulins were detected using polyvalent peroxidase labelled goat antihuman immunoglobulins. Controls included plates coated with fibrin alone or tPA passively adsorbed to the plastic. Sera were considered positive when the A490/630 was above the mean + 2 SD (> 0.055) obtained with normal human serum in 2 independent tests. RESULTS: 25/128 (20%) SSc sera demonstrated antibody reactivity with fibrin bound tPA (mean A490/630 = 0.112). Detailed clinical data were available on 117/128 patients with SSc and on 21/25 anti-tPA positive patients. The mean age of the anti-tPA positive group was 51 yrs and of the anti-tPA negative group 49.6 yrs. Within the anti-tPA positive group there was a significantly higher proportion (p > 0.05) of patients with the CREST (calcinosis, Raynaud's esophageal dysmotility, sclerodactyly, telangiectasias) variant of SSc (7/25 = 28% vs 11/103 = 11%) and pulmonary hypertension (5/21 = 24% vs 6/96 = 6%). CONCLUSION: Our study demonstrates that 20% of unselected patients with SSc have anti-tPA antibodies and that there is a higher representation of patients with CREST syndrome in this subgroup. The high frequency of pulmonary hypertension in the anti-tPA positive group suggests that these autoantibodies may play a pathogenic role in certain patients with SSc.

Adult↗
PubMed1995

Conservative management of incontinence.

This review evaluates the main conservative treatments (general measures, physiotherapy, electrostimulation, mechanical devices, and bladder retraining) with particular emphasis on their effectiveness in the management of urinary incontinence. This is difficult because of the paucity of clinical comparison studies using objective end points, and further work needs to be done to establish more clearly the effectiveness of these measures. However, because the therapies are of low risk, relatively low cost and are reversible, they should be included in the counselling of all incontinent patients regarding treatment options.

Female↗
PubMed1995

Assessing and managing the febrile child.

A fever is defined as a rectal temp over 100.4 degrees F. Fever occurs when the hypothalamic thermoregulation center resets the temperature set point in response to a chain of events initiated by the inflammatory response. Glass thermometers remain the gold standard and electronic thermometers are generally acceptable, but studies do not consistently support the use of infrared ear thermometers in children under 3. Evaluation of the sick child includes observation, assessment of age and temperature risk factors, history and physical, and lab tests. To aid in the assessment of how ill or "toxic" a child appears, the Yale Observation Scale is used. Acetaminophen remains the antipyretic of choice. Febrile seizures are generally benign. Tepid sponge baths are only slightly more effective than acetaminophen alone in reducing fevers, but may be useful for children with a history of febrile seizures or liver disease. While there are many causes of pediatric fevers, they can be grouped into three general categories: fever with localizing signs, fever without localizing signs, and fever of unknown origin. Children with a localized infection are treated with antibiotics, antipyretics, and parent education; children with fever of unknown origin are referred for more in-depth evaluation. The management of children presenting with fever without a source is discussed in detail.

Algorithms↗