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R Klein

Publications and source records attributed to R Klein.

At least 469 records · Page 26Linked to original sources
PubMed1994

Refractive status in the Beaver Dam Eye Study.

PURPOSE: To describe the prevalence of refractive errors in a population of adult Americans. METHODS: From 1988 to 1990, 4926 adults who were 43 to 84 years of age and living in Beaver Dam, Wisconsin at the time of the 1987-1988 census were examined. Refractions were performed according to a modification of the Early Treatment Diabetic Retinopathy Study protocol. Included in this study were 4533 people who had not undergone cataract surgery and who had a best corrected visual acuity better than 20/40 in at least one eye. Myopia was defined as a refractive error less than -0.50 diopters; hyperopia was defined as a refractive error greater than +0.50 diopters. RESULTS: Hyperopia was more frequent than myopia in the study group (age-adjusted of 49.0% and 26.2% in right eyes, respectively, P = 0.0001). The prevalence of hyperopia in the right eye increased with increasing age from 22.1% in those 43 to 54 years of age to 68.5% in those 75 years of age or older. The prevalence of myopia in the right eye decreased from 43.0% in those 43 to 54 years of age to 14.4% in those 75 years of age or older. There was significant relationship between education level and refractive error (age adjusted r = -0.32, P = 0.0001). Neither household income nor occupation was associated with refractive error in our data. CONCLUSION: These cross-sectional data indicate age-related differences in refractive status in an adult population and suggest that education is associated with myopia independent of age.

Adult↗
PubMed1994

Flicker sensitivity and fundus appearance in pre-exudative age-related maculopathy.

PURPOSE: To evaluate whether foveal flicker sensitivity and fundus appearance are good predictors of exudative age-related maculopathy (ARM) when the effects of aging, retinal illuminance, and criterion differences are controlled. METHODS: Fellow eyes of monocular exudative ARM patients were tested at baseline. Seven of these eyes have now developed exudative ARM. Therefore, at baseline they were in pre-exudative stages of ARM. The foveal flicker sensitivity and fundus appearance of the pre-exudative and nonconverted eyes were compared with healthy, age-matched eyes. The flicker stimulus was a uniform, 2.8 deg circular field at 660 nm, modulated sinusoidally at frequencies from 2.5 to 50 Hz. Fundus photographs were evaluated using the Wisconsin ARM grading system. RESULTS: Flicker modulation sensitivity at two frequencies discriminated pre-exudative from healthy older eyes with 100% accuracy. Using the same criterion, pre-exudative eyes also were discriminated from nonconverted eyes with 100% accuracy. Whereas an overall fundus ARM risk score discriminated pre-exudative from healthy older eyes with 100% accuracy, it did not discriminate pre-exudative from nonconverted eyes at better than chance levels. CONCLUSIONS: There were functional changes in the retina preceding development of exudative ARM. Foveal flicker sensitivity at low- to mid-temporal frequencies seemed highly sensitive to these pre-exudative changes in this relatively small group of subjects. The authors hypothesize that foveal flicker sensitivity is a good predictor of exudative ARM and a sensitive monitor of retinal function in pre-exudative ARM. These predictions are being tested on a larger, independent sample.

Aged↗
PubMed1994

Impact of the 1990 contract for general practitioners on night visiting.

BACKGROUND: The 1990 contract for general practitioners extended the hours of eligibility for night visiting claims by 25% and introduced financial incentives to discourage the use of deputizing services. AIM: This study set out to examine the impact of these contract changes on the rate and pattern of night visiting. METHOD: Family health services authority data were used to compare trends in night visiting before and after the introduction of the new contract. Rates were calculated separately for those authorities which might be expected to have a high rate of visiting because of their demographic structure and those that might be expected to have a high rate because of their socioeconomic composition, thus separating out these two sets of factors combined in the Jarman index. RESULTS: Rates of night visiting increased by 33% between 1989 and 1990 while the proportion of visits made by deputies fell by 19%. These changes could not simply be explained either by the extension of eligible hours or the success of financial incentives in changing behaviour in the appropriate direction. It was found that the effect of the new contract was to increase visiting most in family health services authorities with a high proportion of elderly people living alone, that is, where demand would be expected to be higher. In previous years there had been little variation in visiting rates between authorities with a high proportion of those aged 65 years and over living alone and those with a low proportion. The effect of the contract was also to increase rates of visiting most in affluent authorities, that is, where demand would be predicted to be lower. This again marked a sharp break with trends in previous years in that the gap between the high rates in the deprived family health services authorities and lower rates in the most affluent authorities narrowed. CONCLUSION: The 1990 contract achieved the government's policy aims of promoting night visiting by principals and discouraging the use of deputies in its first year. However, the finding that doctors responded more to demand from elderly people and affluent people than from deprived people presents a challenge both for analysis and for policy. It underlines the importance of disaggregating the Jarman index when examining the impact of policy change on local populations and suggests that general practitioners in the most deprived family health services authorities may lack the capacity or the incentive to respond to the changes introduced in the 1990 contract.

Adolescent↗
PubMed1993

Genetic etiology of nuclear cataract: evidence for a major gene.

Sibling correlations and segregation analysis were used to examine the familial distribution of age-sex-adjusted measures of nuclear sclerosis in 1,247 individuals from 564 sibships in the Beaver Dam Eye Study. There are highly significant sibling correlations for all sibs, and separately for sister-sister, sister-brother, and brother-brother pairs. Two transformed normal distributions give the best fit to the data. The hypothesis of mendelian transmission of a major effect cannot be rejected, but the hypothesis of a random environmental major effect is rejected. The parameters of the tau AB free model showed close similarity to the values expected under a mendelian hypothesis. Our results suggest that a single major gene can account for 35% of the total variability of age-sex-adjusted measures of nuclear sclerosis.

Adult↗
PubMed1993

The bottom line.

Explore the source record for details and available documents.

Accreditation↗
PubMed1993

The animal specimens of terrestrial and limnetic ecosystems in the environmental specimen banking programme of Germany.

In the terrestrial and limnetic sampling areas of the Environmental Specimen Banking Programme of Germany five animal species were collected. The goal of this paper is to show first the concept and criteria of the specimen selection for Environmental Specimen Banking with regard to the function of the specimens in the concept of ESB which refers to the role of the species in the trophic levels of the different ecosystems. Secondly, the substantial parts of the sampling operation procedures like the sampling design and the procedure of sampling are shown for five animal specimens.

Animals↗
PubMed1993

Targeted disruption of the trkB neurotrophin receptor gene results in nervous system lesions and neonatal death.

We have generated mice carrying a germline mutation in the tyrosine kinase catalytic domain of the trkB gene. This mutation eliminates expression of gp145trkB, a protein-tyrosine kinase that serves as the signaling receptor for two members of the nerve growth factor family of neurotrophins, brain-derived neurotrophic factor and neurotrophin-4. Mice homozygous for this mutation, trkBTK(-/-), develop to birth. However, these animals do not display feeding activity, and most die by P1. Neuroanatomical examination of trkBTK (-/-) mice revealed neuronal deficiencies in the central (facial motor nucleus and spinal cord) and peripheral (trigeminal and dorsal root ganglia) nervous systems. These findings illustrate the role of the gp145trkB protein-tyrosine kinase receptor in the ontogeny of the mammalian nervous system.

Animals↗
PubMed1993

Dimensions of rationing: who should do what?

Priority setting is a complex interaction of multiple decisions at various levels in the organisation and constrained by history. There is no self evident set of ethical principles or analytical tools to determine what decisions we should take at various levels, nor is there an obvious or easy way to resolve the clash of claims on resources. To make priority setting more "rational" we should concentrate on the processes and structure of decision making and the relation of macro and micro decisions. The debate should promote reasoned, informed, and open argument, draw on a variety of perspectives, and involve a plurality of interests. The aim must be to build up, over time, the capacity to engage in continuous, collective argument.

Budgets↗
PubMed1993

Rationing in practice: the case of in vitro fertilisation.

One of the few examples of explicit rationing in the National Health Service is provided by in vitro fertilisation. Of six purchasing authorities examined three have decided against buying in vitro fertilisation while three have decided in favour. The decisions reflect local factors such as the absence or presence of local providers and the views of the public and health professionals. But in vitro fertilisation also illustrates some of the wider issues involved in all decisions about purchasing: questions about what should be provided by the National Health Service, about what procedures should be compared when weighing up value for money, and whether equity demands national decisions about what to provide.

Decision Making, Organizational↗
PubMed1993

High-affinity nerve growth factor receptor (Trk) immunoreactivity is localized in cholinergic neurons of the basal forebrain and striatum in the adult rat brain.

Trk-immunoreactivity was observed in basal forebrain and striatal cholinergic neurons, whereas low-affinity NGF receptor immunoreactivity was observed in basal forebrain but not striatal cholinergic neurons. Since NGF exerts trophic actions on both basal forebrain and striatal cholinergic populations, the presence of Trk in these neurons lends strong support for an essential role of Trk in NGF-responsive neurons, but suggests that the low affinity receptor is not necessary for NGF actions in the striatum.

Animals↗
PubMed1993

[Total colectomy and mucosal proctectomy with J-pouch anal anastomosis for ulcerative colitis and familial colonic polyposis].

Total colectomy and mucosal proctectomy with ileal pouch-anal anastomosis is the accepted surgical procedure for ulcerative colitis and familial polyposis of the colon. During 1981-1990, 25 patients with ulcerative colitis or familial polyposis underwent this operation in our department. In the majority a J-pouch was performed. In the early years, an 8 cm rectal muscular sleeve was left. In later cases, in accordance with opinions expressed in the medical literature, the length of the sleeve was shortened to about 3 cm. We present the functional results and the early and late complications on follow-up of up to 10 years (mean 3.5 years). Although this operation is not the ideal solution, it is better than the alternatives and is the surgical procedure of choice.

Adolescent↗
PubMed1993

The Beaver Dam Eye Study: the relation of age-related maculopathy to smoking.

There are conflicting reports regarding the relation of cigarette smoking to age-related maculopathy, a major cause of blindness in the United States. In this report, the authors examined this association in people aged 43-86 years (n = 4,771) who participated in the Beaver Dam Eye Study, Beaver Dam, Wisconsin (1988-1990). Exposure data on cigarette smoking were derived from questions about present and past smoking, duration of smoking, and the number of cigarettes smoked per day. Age-related maculopathy status was determined by grading stereoscopic color fundus photographs using the Wisconsin Age-related Maculopathy Grading System. Smoking status, pack-years smoked, and current exposure to passive smoking were not associated with drusen characteristics (type, area, and confluence) or signs of early age-related maculopathy in any age-sex group studied, except for a higher frequency of increased retinal pigment in males who had ever smoked compared with those who had never smoked. The relative odds for exudative macular degeneration, one form of late age-related maculopathy, in females who were current smokers was 2.50 (95% confidence interval 1.01-6.20) compared with those who were ex-smokers or never smokers; for males, it was 3.29 (95% confidence interval 1.03-10.50). There was no significant relation between smoking status and pure geographic atrophy, another form of late age-related maculopathy. These results suggest that exudative macular degeneration is associated with cigarette smoking and that different forms of macular degeneration may have different etiologies.

Adult↗
PubMed1993

Alcohol use and lens opacities in the Beaver Dam Eye Study.

The relationship between alcohol use and lens opacities was examined in a large (N = 4926) population-based study of adults aged 43 to 86 years in Beaver Dam, Wis. These data were collected from 1988 to 1990. Alcohol history was determined by a standardized questionnaire. Prevalence and severity of cataract were determined by masked grading of photographs obtained using a slit-lamp camera and retroillumination. A history of heavy drinking was related to more severe nuclear sclerotic, cortical, and posterior subcapsular opacities (odds ratios, 1.34, 1.38, and 1.57, respectively). These relationships remained after adjusting for other risk factors such as smoking. Moderate liquor consumption was associated with less severe nuclear sclerosis (odds ratio, 0.81). Participants who drank wine had less severe nuclear sclerosis (odds ratio, 0.84) and cortical opacities (odds ratio, 0.84) than those who did not. Increased consumption of beer was related to increased risk of cortical opacities.

Adult↗
PubMed1993

Sunlight and age-related macular degeneration. The Beaver Dam Eye Study.

OBJECTIVE: To investigate the relationship of sunlight exposure with age-related maculopathy. This was investigated in the population-based Beaver Dam Eye Study. DESIGN: In this cross-sectional population-based study, questionnaire data about sunlight exposure were obtained. Stereoscopic color fundus photographs were graded to determine the presence of age-related maculopathy. PARTICIPANTS: People aged 43 through 84 years who resided in Beaver Dam, Wis, between 1987 and 1988 were examined between 1988 and 1990. RESULTS: Light exposure was not associated with early age-related maculopathy in women. In men, after adjusting for age, the amount of time spent outdoors in summer was associated with increased retinal pigment (odds ratio [OR], 1.44; 95% confidence interval [CI], 1.01 to 2.04). Wearing eyeglasses was inversely associated with increased retinal pigment (OR, 0.75; 95% CI, 0.58 to 0.97), and the use of hats and sunglasses was inversely associated with soft indistinct drusen (OR, 0.61; 95% CI, 0.38 to 0.98). The amount of leisure time spent outdoors in summer was significantly associated with exudative macular degeneration (OR, 2.26; 95% CI, 1.06 to 4.81) and late maculopathy (OR, 2.19; 95% CI, 1.12 to 4.25). There were no associations between estimated ambient UV-B exposure and age-related maculopathy. CONCLUSIONS: These data suggest that exposure to sunlight may be associated with age-related maculopathy. However, longitudinal studies of these associations are needed.

Adult↗