Biomedical subjects
Publications and source records attributed to B Smith.
An outline is given of an approach to the health-for-all goals which involves optimizing resource use, prioritizing people's well-being, achieving excellence and a measurable impact at all levels of care, and solving health problems in a broad developmental context.
The aim of this laboratory study was to determine whether the diagnostic potential of bite-wing radiographs in the diagnosis of occlusal caries could be improved by alteration of X-ray beam properties. Bite-wing radiographs of molar teeth with 16 sound and 32 carious occlusal surfaces were taken at conventional settings of 65 kVp, 15 mA and 0.3 s (4.5 mAs) and at 70 kVp, 10 mA and 1.0 s (10 mAs), to produce a darker overexposed film. Results showed that, although the overexposed radiograph resulted in more correct diagnosis of dentine caries, its use increased the number of false-positive diagnoses. More importantly, the experimental exposure factors would have led to an unacceptably high radiation dose to the patient with arguable diagnostic benefit. As such it cannot be recommended in any way for patient examination.
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Pathology case records of 3,514 aborted fetuses, stillborn foals, or foals that died < 24 hours after birth and of 13 placentas from mares whose foals were weak or unthrifty at birth were reviewed to determine the cause of abortion, death, or illness. Fetoplacental infection caused by bacteria (n = 628), equine herpesvirus (143), fungi (61), or placentitis (351), in which an etiologic agent could not be defined, was the most common diagnosis. Complications of birth, including neonatal asphyxia, dystocia, or trauma, were the second most common cause of mortality and were diagnosed in 19% of the cases (679). Other common diagnoses were placental edema or premature separation of placenta (249), development of twins (221), contracted foal syndrome (188), other congenital anomalies (160), and umbilical cord abnormalities (121). Less common conditions were placental villous atrophy or body pregnancy (81), fetal diarrhea syndrome (34), and neoplasms or miscellaneous conditions (26). A diagnosis was not established in 16% of the cases seen (585). The study revealed that leptospirosis (78) was an important cause of bacterial abortion in mares, and that infection by a nocardioform actinomycete (45) was an important cause of chronic placentitis.
Lasalocid sodium was accidentally introduced into the feed of several broiler breeder chicken farms at levels between 115 and 150 ppm. On one farm, leg weakness and ataxia were observed in a few cockerels. A reduction in egg production and a sharp decrease in fertility and hatchability were observed in all the flocks receiving the contaminated feed. Many piping chicks were unable to hatch and there was an increase in the number of weak ataxic chicks at the hatchery. Histological examination of the muscle tissues of the affected cockerels, the piping chicks unable to hatch and the one-day-old chicks with leg weakness and ataxia revealed severe muscle damage. Increasing levels of lasalocid were detected in the yolk of eggs collected from the affected flocks.
OBJECTIVE: To describe the frequency and characteristics of asthma attacks in the United Kingdom and to compare actual management with recommended guidelines for the management of attacks. DESIGN: Correspondence survey. SETTING: 218 general practices in the United Kingdom. SUBJECTS: 1775 patients of all ages who had a total of 1805 asthma attacks over three months. MAIN OUTCOME MEASURES: Patient characteristics, place of management of attacks, comparison of actual management with recommended guidelines. RESULTS: Of the 1805 attacks, 300 occurred in boys aged 0-9, 144 in girls aged 0-9, and 118 in women aged 20-29. The estimated frequency of attacks in the community was 14.3 per 1000 patients per year. 1546 (86%) patients with attacks were managed within general practice, 225 (12%) were admitted to hospital, and 34 (2%) were discharged from an accident and emergency department. Two patients died. On initial presentation, 248 (14%) patients were "not breathless," 900 (50%) were "moderately breathless," 535 (30%) were "breathless and distressed," 68 (4%) were "too breathless to talk," and 2 were "moribund." Recording of clinical data was variable. Underuse of nebulised bronchodilators and systemic steroid was apparent in all grades of clinical severity. Contrary to current guidelines for asthma management, "step up" in maintenance therapy after an attack was often not practised. CONCLUSION: Reported management was at variance with recommended guidelines. This has major implications for the design and distribution of future guidelines.
Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder that causes episodes of focal demyelinating neuropathy following minor trauma to peripheral nerves. We assign the HNPP locus to chromosome 17p11.2 and demonstrate the presence of a large interstitial deletion associated with this disorder in three unrelated pedigrees. De novo deletion is documented in one pedigree. The deleted region appears uniform in all pedigrees and includes the gene for peripheral myelin protein 22 (PMP-22), suggesting that underexpression of PMP-22 may cause HNPP. The deletion in HNPP spans approximately 1.5 Mb and includes all markers that are known to map within the Charcot-Marie-Tooth neuropathy type 1A (CMT1A) duplication. Furthermore, the breakpoints in HNPP and CMT1A map to the same intervals in 17p11.2, suggesting that these genetic disorders may be the result of reciprocal products of unequal crossover.
A population-based study was conducted in an attempt to predict which child's epilepsy will remit. Use of data from a regional electroencephalography laboratory allowed identification of all children in Nova Scotia with epilepsy onset from 1977 through 1985 (excluding those with absence and "minor motor" seizures). Children were followed for an average of 7 years. On the basis of clinical characteristics, a multivariate analysis was used to develop a scoring scheme to predict remission (defined as off medication at the end of the follow-up period). Survival curve methods were used to estimate the duration of medication treatment for those with remission. Of the 504 eligible patients, approximately 70% became seizure free long enough to discontinue medication. Approximately 70% of those stopping medication a first time remained seizure free. At the end of follow-up, 55% of the total cohort were in remission. At diagnosis, the best predictors of remission were age < 12 years at onset, normal intelligence, no prior neonatal seizures, and fewer than 21 seizures before treatment. If predicted to have a remission, then, on the basis of survival curve analysis, 80% were without medication 100 months after diagnosis. After 12 months of treatment, prediction was enhanced by including a score for the number of seizures between 6 and 12 months on treatment. We conclude that approximately 55% of childhood epilepsy will remit. Our scoring system predicts reasonably accurately who will have a remission and when medication is likely to be discontinued.
We studied social outcome for all the normally intelligent children in our province with onset of epilepsy between 1977 and 1985 (excluding absence and "minor motor" seizures). After follow-up averaging 7 1/2 years, the 337 patients were 7 to 28 years of age. Outcome measures were age dependent. Of those old enough to be at risk, the percentage with each unfavorable outcome was as follows: school failure 34%, use of special educational resources 34%, mental health consultation 22%, psychotropic medication 5%, unemployment 20%, social isolation 27%, inadvertent pregnancy 12%, and criminal conviction 2%. In social isolation 27%, inadvertent pregnancy 12%, and criminal conviction 2%. In a multivariate model correcting for number of potential unfavorable outcomes (based on age at end of follow-up), many variables related to epilepsy, seizure control, and electroencephalographic findings were not associated with social outcome. Only two variables were associated with at least one unfavorable outcome--learning disorder (p < 0.001) and more than 21 seizures before treatment was begun (p < 0.03). The only variable with no unfavorable outcome was simple partial seizures (p < 0.003). Sensitivity and specificity of this model were 54% and 68%, respectively, indicating that social outcome for these children was often not related to biologic factors reflected by the medical details and clinical course of their disorder.
In passive Heymann nephritis (PHN) glomeruli exhibit marked basement membrane expansion around subepithelial immune deposits but they fail to show any change in mRNA levels of type IV collagen, laminin or fibronectin by Northern and slot-blot analysis, or in the amount or distribution of type IV collagen or laminin by immunohistology for up to 12 weeks after disease onset. On the other hand, in situ hybridization (ISH) revealed the appearance of positive cells exhibiting mRNA for the alpha 1 chain of rat type I collagen two to three weeks after the onset of PHN in all glomeruli of all rats. Positive cells persisted for at least eight weeks. In many glomeruli, the location of the clusters of silver grains suggested that they were in visceral epithelial cells. In controls injected with normal sheep IgG, and in early PHN (< 11 days after sheep anti-Fx1A), glomeruli were negative but cells in the renal capsule and adventitia of vessels showed strong ISH and served as positive controls. RNAse pre-treatment and the "sense" probe gave appropriately negative results. RNA from PHN glomeruli contained an alpha 1 type I collagen transcript of the same size as that from rat fibroblasts. These results show that the evolution of glomerular basement membrane expansion in rat membranous nephropathy coincides with the induction of a matrix gene that is not normally expressed in glomerular cells. Further, they suggest that the intercalation of ectopically-expressed matrix molecules may contribute to the production of a disorganized basement membrane.
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OBJECTIVE: To examine the association between self-reported pain and cognitive impairment among frail elderly institution residents. DESIGN: A cross-sectional correlational study. SETTING: A large urban nursing home and congregate apartment complex housing predominantly Jewish elderly. PARTICIPANTS: Seven hundred fifty-eight elderly institution residents (30% in the nursing home, 70% in congregate apartments). The sample was 70% female and averaged 83.3 years of age. MEASUREMENTS: Respondent self-reports tapped pain intensity, number of localized pain complaints, cognitive status, and disability in performance of activities of daily living. Attending physicians or physician assistants rated respondents' health status. MAIN RESULTS: Pain intensity and number of localized pain complaints bore small but significant negative relationships to cognitive impairment. Pain was positively associated with physician-rated ill health and functional disability. The association between pain and cognitive status remained significant even when controlled statistically for effects of physical health and functional disability. Item-by-item examination of localized pain complaints indicated that markedly cognitively impaired individuals were less likely to report pain in the back and joints. However, examination of possible physical causes of reported pain revealed no differences between pain reports of cognitively impaired versus intact individuals in either the presence or the absence of a likely physical cause. CONCLUSIONS: These data provide no evidence for the "masking" of pain complaints by cognitive impairment. They suggest instead that, although cognitively impaired elderly may slightly underreport experienced pain, their self-reports are generally no less valid that those of cognitively intact individuals. Limitations of the research are acknowledged and implications for treatment of cognitively impaired institution residents are discussed.
The costs and experiences of caring for geriatric patients and the effectiveness of a geriatric assessment team have been reviewed in this study from the New South Wales Central Coast. The findings were: that some clients who are referred for placement in nursing homes and who meet standard criteria for admission can be maintained in the community; the cost to the taxpayer of persons admitted to nursing homes was at least $449 to $776 per week (1991 prices), compared to an average cost of $89 per week to maintain at home those whose original assessment met all the criteria for nursing home placement; assessments of needs of some clients were being conducted by five or more separate agencies which led to increased costs and created distrust and confusion for the client; a key factor in the decision to maintain a client in the community was found to be the availability and motivation of carers. A geriatric assessment team has an essential role in mobilising expert assessment and facilitates access to community-based support services to obviate or delay admissions to nursing homes.
A novel immunochromatographic assay, the CARDS O.S. MONO test (Pacific Biotech, San Diego, Calif.), and a latex agglutination test, the Infectious Mononucleosis Kit (Unipath Ltd., Hampshire, United Kingdom) were compared with the Paul-Bunnell-Davidsohn test. Of the 957 serum specimens studied, 78 were positive and 879 were negative by the Paul-Bunnell-Davidsohn test. After discrepancies were resolved by determining Epstein-Barr virus serology, the sensitivities of the CARDS O.S. MONO test and the Infectious Mononucleosis Kit were 91.0 and 96.2%, respectively, and both tests had a specificity and a positive predictive value of 100% and a negative predictive value and overall agreement of greater than 99%. The results show that both tests can accurately detect infectious mononucleosis-associated heterophile antibodies.
Cortical (immature) thymocytes are widely reported to express intermediate to high levels of receptors for the lectin, peanut agglutinin (PNA). Light-scatter studies of murine fetal thymocytes stained with PNA or anti-mouse CD4 and CD8 monoclonal antibodies indicated, however, that the most immature CD4-8- (DN) thymocyte subpopulation binds levels of PNA commonly described as PNAlo. Evaluation of the PNA binding characteristics of fetal thymocytes negative for the CD8 antigen confirmed the existence of a major population (approximately 20% of total cells) of CD4-8- PNAlo fetal thymocytes. The majority of these DN thymocytes were subsequently found to bind sub-agglutinating levels of PNA, similar to mature CD4+ or CD8+ single positive (SP) thymocytes. Given this information, an immunomodulating compound (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) known to produce a maturational delay in murine thymocytes was tested for a possible concurrent effect on thymocyte PNA lectin binding. A TCDD-induced increase in DN thymocytes was found to be paralleled by an increase of equal magnitude in PNAlo thymocytes. Taken together, these data provide evidence that acquisition of the PNA receptor may be a maturational event occurring during the DN stage of thymocyte ontogeny. Further, these results suggest that separation of thymocytes into mature (medullary) and immature (cortical) subpopulations by PNA agglutination may result in contamination of medullary cells by the most immature (DN) subpopulation of thymocytes.
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