Search PubMed⌕ Search

Biomedical subjects

R J Smith

Publications and source records attributed to R J Smith.

At least 343 records · Page 19Linked to original sources
PubMed1992

Evaluation of higher-level auditory function in children with asymptomatic congenital cytomegalovirus infection.

Higher-level auditory/cognitive functions were evaluated in 16 children: eight with asymptomatic congenital cytomegalovirus (CMV) infections and eight children documented not to have asymptomatic congenital CMV infections. Hearing sensitivity was within normal limits in all subjects. Results in both groups were within the normal range on the screening measures of verbal abilities, visual perception, social behavior, and memory span. In contrast, results of the auditory measures revealed abnormal dichotic speech perception, delayed latencies on auditory brainstem evoked responses, and disproportionately slow reaction times in a difficult listening condition (Stroop task). With the exception of dichotic speech perception, however, the pattern of auditory results suggested subtle disorders that were difficult to discern unequivocally with the small subject sample. Further studies are encouraged to determine the status of higher-level auditory/cognitive functions in children with asymptomatic congenital CMV infections.

Child↗
PubMed1992

Methodologic issues in using epidemiologic studies of occupational cohorts for cancer risk assessment.

This paper focuses on presenting a review and discussion of the major methodologic issues involved in using epidemiologic studies of occupational groups for assessing human cancer risks. Although animal studies have been most often used for quantitative risk assessment, it is generally recognized that well conducted epidemiologic studies would provide the best basis for estimating human risk. However, there are several features related to the design and analysis of epidemiologic studies which frequently limit their usefulness for quantitating risks. The lack of accurate information on exposure in epidemiologic studies is perhaps the most frequently cited limitation of these studies for risk assessment. However, other features of epidemiologic study design such as statistical power, length of follow-up, selection bias, confounding and effect modification may also limit the inferences that can be drawn from these studies. Furthermore even when the aforementioned limitations are overcome, substantial uncertainty exists concerning the choice of an appropriate statistical (or biologic) model for extrapolation beyond the range of exposures observed in a particular study. An empirical example is provided in which estimates of risk varied by nearly 3 orders of magnitude depending on which functional form of the model was chosen. Modeling of epidemiologic data for QRA should be based upon internal comparisons rather than on modeling Standardized Mortality Ratios (SMRs) when possible. Because of the limitations discussed in this paper, epidemiologic data should not be viewed as a panacea for the problems inherent in using animal bioassay data for QRA.(ABSTRACT TRUNCATED AT 250 WORDS)

Bias↗
PubMed1992

Characterization of the clinical features of five families with hereditary primary cutaneous lichen amyloidosis and multiple endocrine neoplasia type 2.

The hereditary conditions of primary cutaneous lichen amyloidosis and multiple endocrine neoplasia type 2 (MEN 2) are rare clinical entities. The initial reports of two families in which the two conditions coincided have led to the identification of at least eight additional families with this clinical syndrome. In this report we describe the clinical features in five of these eight families. The salient feature in these five families is the presence of unilateral (46%) or bilateral (64%) pruritic and lichenoid skin lesions located over the upper portion of the back. Family members describe these skin lesions as intermittently intensely pruritic leading to scratching and excoriation of the upper back region. The presence of MEN 2 has been documented in 97% of family members with this skin lesion, the one exception being a child who is at risk for development of MEN 2A in whom the diagnosis has not yet been made. Of family members who have MEN 2A, 27% do not have an identifiable skin lesion, although the skin lesion developed in one patient two years after a curative thyroidectomy for medullary thyroid carcinoma (MTC). Four of the five families have members with pheochromocytoma; one with five affected members has only MTC. The finding of this clinical syndrome in geographically diverse portions of the world and the lack of overlap with MEN 2A without the skin lesion suggest it is a distinct clinical variant of MEN 2A.

Adolescent↗
PubMed1992

Gene mapping of the Usher syndromes.

USH is an autosomal recessive group of diseases characterized by auditory impairment and visual loss owing to RP. Two common types of USH are known, types I and II. USH type I is characterized by a congenital severe to profound hearing impairment, absent vestibular function, and a progressive pigmentary retinopathy. Persons with type I do not find hearing aids useful, have delayed motor development, and experience progressive night blindness and peripheral visual loss, which usually begins in their second decade. USH type II is characterized by a congenital moderate to severe hearing loss with a down-sloping audiogram, normal vestibular function, and a progressive pigmentary retinopathy. Persons with USH2 find hearing aids beneficial, have normal psychomotor development, and experience progressive night blindness and peripheral visual loss, which usually begins in their third decade. Vestibular dysfunction is the best distinguishing hallmark to differentiate USH type I from type II. One USH type II gene (called USH2) has been assigned to chromosome 1q. One USH type I gene has been tentatively assigned to chromosome 14q. There are other USH genes that have not yet been localized.

Chromosome Mapping↗
PubMed1992

How do we classify functional status?

The original question "How do we classify functional status?" is rephrased as "How do we order or arrange the limitations of function of primary care patients in classes?". After a review of the functions to be considered, the concept of functional status is presented using empirical data from the research project "Morbidity and Functional Status of the Elderly." The group studied consisted of 5,502 patients older than age 65 and 25 general practitioners in 12 practices. Functional status was assessed using five COOP charts: physical status, psychological status, daily activities, social status, and change. Morbidity was registered using the International Classification of Primary Care (ICPC). At the beginning and end of the study, 30% of the elderly patients assessed their physical functions as seriously limited, whereas 6% to 8% reported psychological problems and limitations in daily activities or social contacts. During the encounters, more serious limitations were recorded: 35% of encounters involved serious physical limitations; 18% involved serious limitations in activities of daily living, and 11% involved constant psychological problems or limitations in social contact. Women reported more physical limitations than men. Older patients reported more physical limitations than younger ones, and people living in nursing homes reported more limitations than patients living independently. From the disease-specific health profiles, we concluded that the greatest limitation of all aspects of function was scored during encounters for cerebrovascular disease, dementia, and cancer of the lung, stomach, intestine, and breast. Hypertension, "no disease," and "common cold" elicited the lowest functional limitations.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1991

Biologic effects of an interleukin-1 receptor antagonist protein on interleukin-1-stimulated cartilage erosion and chondrocyte responsiveness.

Recombinant human interleukin-1 alpha (IL-1 alpha) and recombinant human IL-1 beta stimulate matrix proteoglycan degradation and inhibit glycosaminoglycan synthesis in bovine nasal cartilage explants. A 17-kd human recombinant IL-1 receptor antagonist protein (IRAP) caused a concentration-dependent (0.2-200 ng/ml) suppression of the effects of IL-1 alpha and IL-1 beta in cartilage organ cultures. IRAP inhibited the binding of radiolabeled IL-1 alpha to rabbit articular chondrocytes. Matrix metalloproteinase (collagenase, gelatinase, and stromelysin) and prostanoid production by IL-1-activated rabbit articular chondrocytes was also suppressed by IRAP. These results could have potential significance in the development of a new antiarthritis therapy based on an IRAP.

Animals↗
PubMed1991

Platelet-derived growth factor potentiates cellular responses of articular chondrocytes to interleukin-1.

Recombinant human interleukin-1 alpha (IL-1 alpha) induced a time-dependent (0-72 hours) and concentration-dependent (0.01-10 ng/ml) production of metalloproteinases (collagenase, gelatinase, stromelysin) and prostaglandin E2 (PGE2) in rabbit articular chondrocytes (RAC). Exposure of RAC to recombinant human platelet-derived growth factor homodimer BB (PDGF-BB; 2-200 ng/ml) in the presence of stimulatory and substimulatory concentrations of IL-1 alpha resulted in a marked augmentation of metalloproteinase and PGE2 production. PDGF-BB exerted no agonist effects on RAC responsiveness. PDGF-BB up-regulated the number of IL-1 receptors per chondrocyte but had no effect on receptor affinity. Cycloheximide and actinomycin D caused a concentration-dependent suppression of the PDGF-BB-mediated potentiation of radiolabeled IL-1 alpha binding to RAC and cell responsiveness to IL-1 alpha. Similarly, IL-1 increased the number of PDGF receptors on RAC without changing receptor affinity. These data are discussed within the context of cytokine-growth factor interactions as components of the pathogenesis of arthritic diseases.

Animals↗
PubMed1991

Comparison of treatment effects with labial and lingual fixed appliances.

Pretreatment and posttreatment lateral cephalometric radiographs were evaluated for 120 patients--40 from each of three private practices. Twenty patients from each office had been treated with labial fixed appliances and 20 with lingual fixed appliances. There were no significant differences between labial and lingual appliances with respect to the change of any cephalometric measurement during treatment (posttreatment value minus pretreatment value). Differences among patients from the three offices were found only for upper incisor vertical position, and these appeared to reflect differences in treatment objectives rather than in appliances. However, several significant differences were found when changes during treatment were evaluated according to extraction pattern, without reference to the type of appliance used. There was no evidence that the mechanics required with lingual appliances necessarily led to any changes in treatment results, as determined by the cephalometric measurements used in this study.

Adolescent↗
PubMed1991

Identifying normal and abnormal development of dental occlusion.

Abnormalities of occlusal development manifest themselves clinically as a need for orthodontic treatment. There are many circumstances in which there is an interaction between traditional pediatric concerns and occlusal abnormalities. In some cases medical treatment impacts on the development of occlusion. In other cases, occlusal abnormalities contribute to clinical conditions seemingly far removed from the dentition.

Adolescent↗
PubMed1991

Laparoscopy and the general surgeon.

Laparoscopic cholecystectomy has belatedly awakened the general surgical community to the concept of closed abdominal surgery. Current techniques have largely been developed by our colleagues in gynecology. The unanticipated demand by the public has placed unprecedented pressure on our systems for training, credentialing, developing, supplying, and evaluating changes in surgical technique. The diagnostic value of laparoscopy has been documented by a handful of general surgeons over the past several decades and is likely to become a more widely accepted technique. The potential of future developments in video-controlled operations is immense.

History, 19th Century↗
PubMed1991

Cognitive impairment and dementia in Parkinson's disease: a controlled study.

The performance of 47 patients with Parkinson's disease on a battery of tests of cognition, motor function, disability and mood was compared with the performance of 47 healthy control subjects who were matched to the patients on the basis of age, sex and pre-morbid IQ. An increased prevalence of impairment over a range of cognitive functions was observed in the Parkinson's disease patients as compared with their matched controls. The differences between the Parkinson's disease patients and controls could not be accounted for by factors such as depressed mood, effects of medication or motor impairment. Our findings are discussed in relation to the methodology of previous studies in this area and to the need for a comprehensive clinico-pathological longitudinal study.

Activities of Daily Living↗
PubMed1991

Necrotizing fasciitis and nonsteroidal anti-inflammatory drugs.

We have presented a case of fulminant necrotizing fasciitis that occurred after excessive NSAID intake with granulocytopenia. This case parallels those previously reported as outlined in the above discussion. We concur with previous investigators who have concluded that NSAIDs should be used with caution in patients with phlebitis or apparently benign inflammatory cutaneous lesions.

Adult↗