Search PubMed⌕ Search

Biomedical subjects

R Klein

Publications and source records attributed to R Klein.

At least 217 records · Page 12Linked to original sources
PubMed1999

Effects of high-impact exercise on ultrasonic and biochemical indices of skeletal status: A prospective study in young male gymnasts.

Physical activity has been proposed as one strategy to enhance bone mineral acquisition during growth. The aim of this study was to determine whether frequent impact loading associated with gymnastics training confers a skeletal benefit on pre- and peripubertal male gymnasts. We measured broadband ultrasonic attenuation (BUA, dB/MHz) at the calcaneus (CBUA); ultrasound velocity (m/s) at the calcaneus (CVOS), distal radius (RVOS) and phalanx (PVOS); serum osteocalcin (OC); total alkaline phosphatase (ALP) and insulin-like growth factor-I (IGF-I) every 3-4 months over an 18-month period in elite male gymnasts and matched normoactive controls (pubertal stage </=2). Ground reaction forces of common gymnastics maneuvers were determined using a force platform and loading histories of the upper and lower extremities approximated from video recordings. Ultrasound results were expressed as a standardized score (Z score) adjusted for age, height, and weight. At baseline, no differences were detected between the gymnasts (n = 31) and controls (n = 50) for CBUA, although ultrasound velocity at each site was higher in the gymnasts (0.6-1.5 SD) than the predicted mean in controls (p </= 0. 001). Over 18 months, CBUA Z scores increased significantly in the gymnasts from baseline (0.3 vs. 1.0, p < 0.05, n = 18). In contrast, ultrasound velocity did not increase in either group, although CVOS and RVOS remained significantly higher in gymnasts compared with controls (range p < 0.01 and < 0.001). No differences between groups were found for OC, ALP, or IGF-I at any time. Gymnastics training was associated with on average 102 and 217 impacts per session on the upper and lower extremities, respectively, with peak magnitudes of 3.6 and 10.4 times body weight. These results suggest that frequent high-impact, weight-bearing exercise during the pre and peripubertal period may enhance the mechanical competence of the skeleton, perhaps offering an important strategy for osteoporosis prevention if the benefits are maintained.

Body Constitution↗
PubMed1999

Correlates of urinary symptom scores in men.

OBJECTIVES: This study determined the prevalence of urinary symptoms and their relationship to characteristics of a cohort of men in Beaver Dam, Wis, from 1993 to 1995. METHODS: A standardized questionnaire concerning urinary symptoms (the American Urological Association Urinary Symptom Questionnaire) was administered. RESULTS: All outcomes were associated with age and history of enlarged prostate. Urinary frequency (57%) and nocturia (65%) were the most common individual symptoms. Diuretic usage, diabetes, history of cardiovascular disease, and smoking were related to specific symptoms. CONCLUSIONS: While urinary symptoms are associated with age and history of enlarged prostate, symptoms may also be attributable to other diseases and exposures.

Age Factors↗
PubMed1999

Prevalence of self-rated visual impairment among adults with diabetes.

OBJECTIVES: This study estimated the prevalence of self-rated visual impairment among US adults with diabetes and identified correlates of such impairment. METHODS: Self-reported data from the 1995 Behavioral Risk Factor Surveillance System survey of adults 18 years and older with diabetes were analyzed. Correlates of visual impairment were examined by multiple logistic regression analysis. RESULTS: The prevalence of self-rated visual impairment was 24.8% (95% confidence interval [CI] = 22.3%, 27.3%). Among insulin users, multivariable-adjusted odds ratios were 4.9 (95% CI = 2.6, 9.2) for those who had not completed high school and 1.8 (95% CI = 1.0, 2.8) for those who had completed high school compared with those with higher levels of education. Comparable estimates of odds ratios for nonusers of insulin were 2.2 (95% CI = 1.4, 3.4) and 1.3 (95% CI = 0.9, 2.0), respectively. Among nonusers, the adjusted odds for minority adults were 2.4 (95% CI = 1.0, 3.7) times the odds for non-Hispanic Whites. CONCLUSIONS: By these data, 1.6 million US adults with diabetes reported having some degree of visual impairment. Future research on the specific causes of visual impairment may help in estimating the avoidable public health burden.

Adult↗
PubMed1999

Exogenous estrogen exposures and changes in diabetic retinopathy. The Wisconsin Epidemiologic Study of Diabetic Retinopathy.

OBJECTIVE: To investigate whether the use of exogenous estrogen is associated with changes in the severity of diabetic retinopathy and the incidence of macular edema. RESEARCH DESIGN AND METHODS: The study design involved observation of two well-defined cohorts of women with diabetes. One group was diagnosed with diabetes at < 30 years of age and used insulin (younger-onset group), and the other group was diagnosed at > or = 30 years of age with no criteria regarding therapy (older-onset group). Subjects received standard examinations, medical interviews, and retinal photography in 1980-1982. Specific questions about exogenous hormone exposure were added to the study questionnaire at the first follow-up examination 4 years after the baseline examination. Change in the severity of retinopathy 6 and 10 years after the 4-year follow-up examination were examined regarding the use of oral contraceptives at the first follow-up examination in the younger-onset group and at 6 years after the first follow-up examination regarding hormone replacement therapy in the older-onset group. RESULTS: Changes in the severity of retinopathy and incidence of macular edema were unrelated to either type of estrogen exposure in univariable and multivariable analyses. CONCLUSIONS: These data are compatible with the hypothesis that the medications used by our population do not affect the severity of diabetic retinopathy or macular edema.

Adult↗
PubMed1999

Mortality and hormone-related exposures in women with diabetes.

OBJECTIVE: Hormone-related events and exposures are related to mortality and especially to cardiovascular disease in women. We evaluated whether such exposures influenced risk in a well-defined group of women with diabetes. RESEARCH DESIGN AND METHODS: Women with younger- and older-onset diabetes who were identified during a population-based study were queried about number of pregnancies, age at menarche, use of oral contraceptives, use of estrogen replacement therapy, and menopausal status at examinations in 1984-1986. Analyses are limited to women aged > or = 18 years (n = 398 and 542 in those with younger- and older-onset diabetes, respectively). Cohort mortality was monitored carefully, and causes of death were abstracted from death certificates. RESULTS: There were 58 deaths in the first group and 338 deaths in the second group since the 1984-1986 examination. The number of pregnancies was significantly associated with all-cause mortality (hazard ratio, 0.96 [95% CI 0.92-1.00]) in older-onset women only. CONCLUSIONS: These data suggest and are compatible with the notion that the hormone exposures examined are unrelated to cardiovascular mortality in women with diabetes, with the exception of a minimal effect of the number of pregnancies in older-onset women. Whether there is a difference in these exposure-outcome relationships between women with diabetes and those without diabetes is uncertain and requires further investigation.

Adolescent↗
PubMed1999

The 10-year incidence of renal insufficiency in people with type 1 diabetes.

OBJECTIVE: To describe the 10-year decrease in estimated creatinine clearance and the incidence of renal insufficiency and end-stage renal disease in a cohort of people with type 1 diabetes. RESEARCH DESIGN AND METHODS: A population-based cohort of individuals with younger-onset diabetes (diagnosed at < 30 years old and taking insulin) participated in an examination during 1984-1986 (n = 891), a 6-year follow-up examination during 1990-1992 (n = 765), and a 10-year follow-up examination during 1995-1996 (n = 634). Serum creatinine and risk factors were measured during standardized protocols at each examination. Estimated adjusted creatinine clearance was computed by a modification of the Cockroft-Gault formula. A clinically meaningful change was defined as a decrease in the estimated annual creatinine clearance of > or = 3 ml.min-1.1.73 m-2.year-1. Renal insufficiency was defined by the development of a serum creatinine of 2.0 mg/dl or greater after the 1984-1986 examination. RESULTS: The 10-year estimated incidence of an annual decrease in the creatinine clearance of > or = 3 ml.min-1.1.73 m-2 for the cohort was 52.5%, and the cumulative 10-year incidence of renal insufficiency and end-stage renal failure was 14.4%. In univariate analyses, incidence of a decrease in the estimated creatinine clearance of > or = 3 ml.min-1.1.73 m-2.year-1 and the incidence of renal insufficiency were both related to higher glycosylated hemoglobin; higher diastolic blood pressure; the presence of microalbuminuria and gross proteinuria; more severe retinopathy; and a history of loss of tactile sensation or temperature sensitivity at baseline. In logistic regression analysis, after adjusting for the presence of microalbuminuria and gross proteinuria at baseline, higher glycosylated hemoglobin and higher diastolic blood pressure were associated with decreasing estimated creatinine clearance. In logistic regression analyses, after adjusting for the presence of microalbuminuria and gross proteinuria at baseline, the incidence of renal insufficiency was independently associated with age, glycosylated hemoglobin, hypertension, and serum HDL cholesterol. CONCLUSIONS: These data suggest that a public health approach aimed at controlling glycemia, blood pressure, and serum lipids might result in reducing the rate of decline in renal function and development of renal insufficiency in people with type 1 diabetes.

Adult↗
PubMed1999

The 14-year incidence of lower-extremity amputations in a diabetic population. The Wisconsin Epidemiologic Study of Diabetic Retinopathy.

OBJECTIVE: To estimate the cumulative 14-year incidence of lower-extremity amputations (LEAs) and evaluate risk factors for LEA. RESEARCH DESIGN AND METHODS: Study subjects consisted of population-based cohorts of younger-onset (diagnosed before age 30 years and taking insulin, n = 906) and older-onset (diagnosed after age 30 years, n = 984) individuals with diabetes. Subjects participated in baseline (1980-1982), 4-year, 10-year, and 14-year examinations or interviews. LEAs were determined by history. RESULTS: The cumulative 14-year incidence of LEA was 7.2% in younger- and 9.9% in older-onset patients. In multivariable analyses based on the discrete linear logistic model, LEA in the younger-onset group was more likely for males (odds ratio [OR] 5.21 [95% CI 2.50-10.88]), older age (OR for 10 years 1.71 [1.30-2.24]), higher glycosylated hemoglobin (OR for 1% 1.39 [1.22-1.59]), higher diastolic blood pressure (OR for 10 mmHg 1.58 [1.20-2.07]), history of ulcers of the feet (3.19 [1.71-5.95]), and more severe retinopathy (OR for one step 1.16 [1.08-1.24]). In younger-onset patients aged > or = 18, pack-years smoked (OR for 10 years 1.20 [1.03-1.41]) was also associated with LEAs, and daily aspirin use was inversely associated (OR 0.11 [0.01-0.83]). In the older-onset group, LEA was more likely for men (2.66 [1.49, 4.76]) and if the subject had higher glycosylated hemoglobin (OR for 1% 1.25 [1.09-1.43]), higher pulse pressure (OR for 10 mmHg 1.19 [1.04-1.37]), history of ulcers (3.56 [1.84-6.89]), and more severe retinopathy (OR for one step 1.07 [1.00-1.13]). CONCLUSIONS: There are several risk factors for LEA with potential for modification and preventive strategies.

Adolescent↗
PubMed1999

Central neurocytoma of the fourth ventricle. Case report.

The authors report on a 17-year-old boy who suffered from slowly progressive and long-standing symptoms of ataxia, neck pain, and headache. Computerized tomography (CT) and magnetic resonance (MR) imaging revealed a tumor arising from the floor of the fourth ventricle that resulted in a moderate hydrocephalus. A partial resection was performed. Histological and immunohistological findings led to the diagnosis of an atypical central neurocytoma of the fourth ventricle. The imaging features on CT scanning, MR imaging, and proton MR spectroscopy studies, the clinical picture, and the prognosis of this very unusual tumor are discussed. Three cases of neurocytomas in the posterior fossa have been described to date; however, in all three cases some atypical aspects were present. In the present case, with the exception of the very unusual location, both imaging findings and clinical history perfectly met the definition of this rare tumor.

Adolescent↗
PubMed1999

Changes in refractive error over a 5-year interval in the Beaver Dam Eye Study.

PURPOSE: To examine changes in spherical equivalent over a 5-year period in persons 43 to 84 years of age. METHODS: All people 43 to 84 years of age and living in Beaver Dam, Wisconsin, in 1988 were invited for a baseline examination (1988-1990) and a 5-year follow-up examination (1993-1995). Refractions were determined according to the same protocol at both examinations. Aphakic and pseudophakic eyes were excluded as well as eyes with best corrected Snellen visual acuity of 20/40 and worse. After exclusions, refraction was obtained on 3007 right eyes and 3012 left eyes of the 3684 people participating in both examinations. RESULTS: Right and left eyes behaved similarly. Spherical equivalent became more positive in the youngest subjects and more negative in older subjects. After adjusting for other factors, the 5-year change in spherical equivalent of those 45, 55, 65, and 75 years of age was +0.15, +0.18, +0.10, and -0.07D, respectively. Severity of nuclear sclerosis was related to the amount of change. Those with mild nuclear sclerosis at baseline had a change of +0.2 D, whereas those with severe nuclear sclerosis had a change of -0.5 D. The amount of change was also related to gender, diabetes, and age at onset of myopia. It was unrelated to education and baseline spherical equivalent. CONCLUSIONS: Changes in spherical equivalent over a 5-year period were small. Before the age of 70, people became more hyperopic. After the age of 70, people became more myopic. Much of the myopic change may be related to increasing nuclear sclerosis.

Adult↗
PubMed1998

Prevalence of hearing loss in older adults in Beaver Dam, Wisconsin. The Epidemiology of Hearing Loss Study.

There are no recent population-based data on the prevalence of hearing loss in older adults using standard audiometric testing. The population-based Epidemiology of Hearing Loss Study was designed to measure the prevalence of hearing loss in adults aged 48-92 years, residing in Beaver Dam, Wisconsin. Hearing thresholds were measured with standardized protocols using pure-tone air- and bone-conduction audiometry in sound-treated booths. The examination also included an otoscopic evaluation, screening tympanogram, and a questionnaire on hearing-related medical history, noise exposure, other potential risk factors, and self-perceived hearing handicap. Of the 4,541 eligible people, 3,753 (82.6%) participated in the hearing study (1993-1995). The average age of participants was 65.8 years, and 57.7% were women. The prevalence of hearing loss was 45.9%. The odds of hearing loss increased with age (odds ratio (OR) = 1.88 for 5 years, 95% confidence interval (CI) 1.80-1.97) and were greater for men than women (OR = 4.42, 95% CI 3.73-5.24). The male excess of hearing loss remained statistically significant after adjusting for age, education, noise exposure, and occupation (OR = 3.65). These results demonstrate that hearing loss is a very common problem affecting older adults. Epidemiologic studies are needed to understand the genetic, environmental, and sex-related determinants of age-related hearing loss and to identify potential intervention strategies.

Adult↗
PubMed1998

TrkB and neurotrophin-4 are important for development and maintenance of sympathetic preganglionic neurons innervating the adrenal medulla.

The adrenal medulla receives its major presynaptic input from sympathetic preganglionic neurons that are located in the intermediolateral (IML) column of the thoracic spinal cord. The neurotrophic factor concept would predict that these IML neurons receive trophic support from chromaffin cells in the adrenal medulla. We show here that adrenal chromaffin cells in the adult rat store neurotrophin (NT)-4, but do not synthesize or store detectable levels of BDNF or NT-3, respectively. Preganglionic neurons to the adrenal medulla identified by retrograde tracing with fast blue or Fluoro-Gold (FG) express TrkB mRNA. After unilateral destruction of the adrenal medulla, 24% of IML neurons, i.e., all neurons that are preganglionic to the adrenal medulla in spinal cord segments T7-T10, disappear. Administration of NT-4 in gelfoams (6 microgram) implanted into the medullectomized adrenal gland rescued all preganglionic neurons as evidenced by their presence after 4 weeks. NT-3 and cytochrome C were not effective. The action of NT-4 is accompanied by massive sprouting of axons in the vicinity of the NT-4 source as monitored by staining for acetylcholinesterase and synaptophysin immunoreactivity, suggesting that NT-4 may enlarge the terminal field of preganglionic nerves and enhance their access to trophic factors. Analysis of TrkB-deficient mice revealed degenerative changes in axon terminals on chromaffin cells. Furthermore, numbers of FG-labeled IML neurons in spinal cord segments T7-T10 of NT-4-deficient adult mice were significantly reduced. These data are consistent with the notion that NT-4 from chromaffin cells operates through TrkB receptors to regulate development and maintenance of the preganglionic innervation of the adrenal medulla.

Adrenal Medulla↗
PubMed1998

Recognizing occupational disease--taking an effective occupational history.

Occupational exposures contribute to the morbidity and mortality of many diseases. However, occupational diseases continue to be underrecognized even though they are responsible for an estimated 860,000 illnesses and 60,300 deaths each year. Family physicians can play an important role in improving the recognition of occupational disease, preventing progressive illness and disability in their own patients, and contributing to the protection of other workers similarly exposed. This role can be maximized if physicians raise their level of suspicion for workplace disease, develop skills in taking occupational histories and establish routine access to occupational health resources.

Adult↗
PubMed1998

A novel epitope on the C-terminus of SmD1 is recognized by the majority of sera from patients with systemic lupus erythematosus.

The SmD1 protein is a specific target for the autoantibody response in SLE. To further analyze this reactivity epitope, mapping was performed with cellulose-bound 13-mer peptides overlapping 10 amino acids (aa). In this initial approach, 4 out of 15 SLE sera recognized more than five overlapping peptides of the SmD1 C-terminus. Therefore, longer oligopeptides of up to 37 aa of this region were generated and probed for as antigens by ELISA. For the SmD1 aa 83-119 polypeptide, there was a striking increase of reactivity with 70.0% positive reactions out of 167 SLE sera. In contrast, 105 healthy control sera were negative, and only 8.3% of sera from patients with other inflammatory diseases (n = 267) exhibited a response, which was of low level only. The anti-SmD183-119 reactivity was significantly higher in anti-dsDNA antibody positive vs. negative sera (P < 0.001) and correlated with disease activity. Four of five human monoclonal anti-dsDNA antibodies also reacted with SmD183-119. The specificity for SmD1 was demonstrated by inhibition experiments and immunization of rabbits with SmD183-119 inducing SmD1-specific antibodies. In conclusion, the SmD183-119 peptide was demonstrated to be an important and highly specific target of the autoimmune response in SLE. The high sensitivity of this ELISA probably depends on a conformational epitope, which appears not to be accessible in the full-size SmD1 protein.

Amino Acid Sequence↗
PubMed1998

Associations between antioxidant and zinc intake and the 5-year incidence of early age-related maculopathy in the Beaver Dam Eye Study.

Associations between antioxidants and zinc and the 5-year incidence of early, age-related maculopathy (ARM) were investigated in a population-based cohort of middle-aged and older adults participating in the Beaver Dam Eye Study in Beaver Dam, Wisconsin. A food-frequency questionnaire was administered at baseline (1988-1990) to collect dietary information for that time period and a period of time 10 years earlier (1978-1980) from a 50 percent random sample of persons participating in this study. The incidence of the specific lesions of larger drusen (>125 microns) and pigmentary abnormalities and the incidence of any ARM were assessed by masked grading of stereoscopic color fundus photographs in 1,709 persons who participated in 5-year follow-up eye examinations. Significant, but modest, inverse associations (p < 0.05) were observed between intakes of pro-vitamin A carotenoids and dietary vitamin E and the incidence of large drusen and between zinc and the incidence of pigmentary abnormalities. No significant inverse associations were found between antioxidant or zinc intake and the incidence of overall early ARM. If ARM, which is characterized by a broad spectrum of lesions, involves a number of different underlying pathophysiologic processes, then associations between specific antioxidants and the incidence of distinct macular lesions may be biologically important. However, because there were too few incident late ARM cases in this cohort, the authors were unable to assess whether antioxidant intake is associated with the progression of early ARM to late-stage macular degeneration. Clinical trials and longer-term prospective studies are needed to elucidate further the impact of antioxidants and zinc on the development and progression of ARM.

Adult↗