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Biomedical subjects

R Klein

Publications and source records attributed to R Klein.

At least 415 records · Page 23Linked to original sources
PubMed1995

The Wisconsin Epidemiologic Study of Diabetic Retinopathy. XVI. The relationship of C-peptide to the incidence and progression of diabetic retinopathy.

The relationship between plasma C-peptide and the 6-year incidence and progression of diabetic retinopathy was examined in a population-based study in Wisconsin. Individuals with younger-onset (n = 548) and older-onset (n = 459) diabetes were included. C-peptide was measured by radioimmunoassay with Heding's M1230 antiserum. Retinopathy was determined from stereoscopic fundus photographs. Younger- and older-onset insulin-using individuals with undetectable or low plasma C-peptide (< 0.3 nmol/l) at baseline had the highest incidence and rates of progression of retinopathy, whereas older-onset individuals with C-peptides > 0.3 nmol/l had the lowest incidence and rates of progression of retinopathy. However, within each group (younger-onset using insulin, older-onset using insulin, and older-onset not using insulin), after we controlled for other characteristics associated with retinopathy, there was no relationship between higher levels of C-peptide at baseline and lower 6-year incidence or progression of retinopathy. These data suggest that glycemic control, and not C-peptide, is related to the incidence and progression of diabetic retinopathy.

Adult↗
PubMed1995

Ten-year incidence of gross proteinuria in people with diabetes.

There are few population-based epidemiological data describing the long-term incidence of gross proteinuria in people with diabetes. We performed a population-based study in southern Wisconsin of individuals with diabetes diagnosed at either < 30 years of age and taking insulin (younger-onset, n = 666) or > or = 30 years of age either taking (older-onset taking insulin, n = 376) or not taking insulin (older-onset not taking insulin, n = 418). The presence of gross proteinuria (> or = 0.3 g/l) was determined by means of a reagent strip. The incidence of proteinuria in the 10-year interval was 28% in the younger-onset group, it was 40% in the older-onset group taking insulin, and it was 33% in the older-onset group not taking insulin. After we controlled for other risk factors, the 10-year incidence of proteinuria was significantly related to higher glycosylated hemoglobin level and diastolic blood pressure at baseline and to an increase in glycosylated hemoglobin level and an increase in diastolic blood pressure from baseline to the 4-year follow-up in the younger-onset group and to higher glycosylated hemoglobin level, higher systolic blood pressure, and higher total pack-years of cigarettes smoked at baseline and an increase in systolic blood pressure from baseline to the 4-year follow-up in the older-onset groups. These data suggest that modification of three factors--hyperglycemia, high blood pressure, and smoking--may lead to a reduction in the long-term incidence of proteinuria.

Adult↗
PubMed1995

Digoxin does not accelerate progression of diabetic retinopathy.

OBJECTIVE: To test the hypothesis that digoxin, an inhibitor of Na(+)-K(+)-ATPase activity, accelerates the progression of diabetic retinopathy. RESEARCH DESIGN AND METHODS: We compared the incidence and risk of retinopathy in 120 digoxin-taking vs. 867 non-digoxin-taking diabetic participants in the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) and in 117 digoxin-taking vs. 1,883 non-digoxin-taking diabetic subjects in the Early Treatment Diabetic Retinopathy Study (ETDRS). In both studies, retinopathy was detected by grading stereoscopic color photographs using the modified Airlie House classification scheme, and a two-step difference in baseline retinopathy grade was considered significant. RESULTS: After controlling for other risk factors, we found no statistically significant association with either 4-year incidence of retinopathy (WESDR) or progression of retinopathy (WESDR and ETDRS) in patients taking digoxin at baseline compared with those not taking digoxin. CONCLUSIONS: These data suggest that digoxin therapy does not adversely affect the course of diabetic retinopathy.

Adult↗
PubMed1995

Hyperglycemia and microvascular and macrovascular disease in diabetes.

In summary, over the past 16 years, since the publication of Kelly West's book, epidemiological study has provided better insight into the relation of hyperglycemia and diabetic complications. Data from the WESDR demonstrate a strong consistent relationship between hyperglycemia and the incidence and progression of microvascular (diabetic retinopathy, loss of vision, and nephropathy) and macrovascular (amputation and cardiovascular disease mortality) complications in people with IDDM and NIDDM (Figs. 19 and 20). The DCCT has demonstrated that intensive insulin therapy will reduce the incidence and progression of microvascular complications in people with IDDM (22). A number of further challenges await laboratory scientists and epidemiologists regarding hyperglycemia in people with diabetes. There is a need to understand the relation of hyperglycemia to pathogenetic mechanisms that lead to the development of specific complications, to develop new methods to detect and physiologically treat hyperglycemia, and to develop better methods of primary and secondary prevention of diabetic complications in people with IDDM and NIDDM.

Age Factors↗
PubMed1995

Older-onset diabetes and lens opacities. The Beaver Dam Eye Study.

PURPOSE: To determine the prevalence of lens opacities in older-onset diabetic persons. METHODS: A study of age-related eye disease in a population (n = 4926) of adults in Beaver Dam, Wisconsin. Study participants were examined and interviewed according to protocol. Photographs were taken of the lenses of both eyes of all study participants. Photographs were graded in a standard fashion. Diabetes was defined by history, doctors' records and serum glucose criteria. RESULTS: Persons who were diabetic were significantly more likely to have cortical lens opacities (age-adjusted odds ratio 1.72, 95% CI 1.29-2.30 for right eyes) and were more likely to have previously undergone cataract surgery (age-adjusted odds ratio 2.01, 95% CI 1.43-2.82 for either eye) than people without diabetes. Longer duration of diabetes significantly increased the odds of having cortical opacity. CONCLUSION: Older-onset diabetes is associated with increased frequency of a specific age-related lens change, cortical opacity. It is also associated with increased frequency of cataract surgery.

Adult↗
PubMed1995

Familiarity and attention: does what we know affect what we notice?

Previous work on the object and word superiority effects has demonstrated that activation from stored representations can facilitate identification of items in a visual display. We predicted that activation of this sort might exogenously attract visual attention toward items that have stored representations. To test this prediction, we presented a familiar (word) and an unfamiliar (nonword) item simultaneously at unpredictable locations, and after varying delays, moved one of the stimuli. In accord with our prediction, at the shortest intervals subjects were more efficient at discriminating motion of the familiar item. Control data demonstrated that this advantage was due to a competitive interaction and not to the familiarity of the items per se.

Adolescent↗
PubMed1995

Measuring to improve.

Rush Prudential Health Plans, a managed care company located in Chicago, Illinois, is implementing a service quality improvement process across the three products it markets in the Chicago area: The Anchor Plan (a primarily staff model HMO), The Affiliates Plan (a network model HMO), and The Plus Plan (a point of service plan). In 1994, the company instituted an annual member satisfaction research study, conducted across the three plans, and began building a link between external customer requirements and internal operations. The research process consisted of three stages: determining external customer requirements, translating these customer-defined "symptoms" into underlying root causes, and developing a service quality improvement action plan. Rush Prudential determined that traditional "report card" surveys would not meet their goals for the information measurement process. A detailed diagnostic telephone survey was used to provide a picture of the entire clinical encounter, from scheduling an appointment through the time a member left the physician's office.

Chicago↗
PubMed1995

Big bang health care reform--does it work?: the case of Britain's 1991 National Health Service reforms.

The costs and benefits are examined of one of the very few examples of a government driving through health care reform in the face of near unanimous opposition: Britain's 1991 reforms of the National Health Service (NHS), which sought to inject the dynamics of a market into the framework of a universal, tax-financed service. The political costs to the government have been high. The public continues to see the NHS through the eyes of disgruntled doctors and nurses. The benefits, measured in efficiency gains or service improvements, are as yet difficult to establish. However, the NHS has changed in key respects. The balance has shifted from hospital specialists to general practitioners and from providers to purchasers, with increasing emphasis on professional accountability and consumerism. But the NHS continues to evolve as it strives to resolve the tensions implicit in the reforms, and the only certainty is that no future government can return to the pre-1991 situation.

Contract Services↗
PubMed1995

The relationship of age-related maculopathy, cataract, and glaucoma to visual acuity.

PURPOSE: To investigate the relationship of age-related maculopathy, cataract, and glaucoma to visual acuity in the population-based Beaver Dam Eye Study. METHODS: A cross-sectional, population-based study was performed in people 43 through 86 years of age residing in Beaver Dam, Wisconsin, who were identified between 1987 and 1988 and examined (n = 4926) between 1988 and 1990. Of those who participated, 99.4% were white. Visual acuity was measured (n = 4886) using a modification of the Early Treatment Diabetic Retinopathy Study protocol. Stereoscopic color fundus photographs and slit lamp and retroillumination photographs of the lens were graded in a masked fashion using standardized protocols to determine the presence of age-related maculopathy and central cataract. RESULTS: Fifty-seven percent of those who were legally blind had late age-related maculopathy in both eyes. The frequency of visual acuity of 20/200 or worse was not significantly different in eyes with exudative macular degeneration (48%) than in eyes with pure geographic atrophy (42%). While controlling for other factors (age, central cataract, and glaucoma) in participants with both gradable age-related maculopathy and visual acuity measurable in at least one eye (n = 4716), investigators found that each of the early age-related maculopathy lesions was associated with a decrease in visual acuity of approximately two letters or fewer when compared to eyes without these lesions. Late age-related maculopathy was associated with a decrease of approximately seven lines of letters read correctly. CONCLUSION: These data demonstrate that exudative macular degeneration and pure geographic atrophy are the most important causes of legal blindness in this population and that early age-related maculopathy, central cataract, and glaucoma had a small effect on visual acuity.

Adult↗
PubMed1995

Evidence for a major gene for cortical cataract.

PURPOSE: To examine the possible presence of a major gene determining susceptibility to cortical cataract. METHODS: The percentage of the lens area involved with cortical opacity, summed over both eyes, was evaluated in 1275 individuals from the Beaver Dam Eye Study. After adjusting for the effects of age and sex, these measures of cortical cataract were subjected to sibling correlational analysis, commingling analysis, and segregation analysis. The Box and Cox power transformation was applied to the data for the commingling and segregation analyses. Using regressive models, four modes of transmission were examined, and under each mode three hypotheses and a general model were fitted by maximum likelihood and compared. RESULTS: Sister-sister and brother-brother correlations of the adjusted measures of cortical cataract are significant and similar; the brother-sister correlation is not significantly different either from these correlations or from zero. Two commingled distributions give the best fit to the data, especially after power transformation. Under each of four modes of transmission, the hypothesis that best fits the data is one in which there are only two distributions (and, hence, dominance under mendelian transmission), the power transformation parameter is fixed at the estimate obtained from commingling analysis, and there is residual sibling correlation. The data thus suggest the existence of a major effect for cortical cataract. Random environmental influences can be rejected as a cause of this major effect. Our analysis indicates the existence of a significant effect of sex on the residual variance. Allowing for this, the data suggest transmission of a single major gene, though this may not be the sole cause of the commingled distributions. CONCLUSIONS: Assuming a common variance for the two sexes, a single major gene can account for 58% of the variability of age- and sex-adjusted measures of cortical cataract. With the variance sex dependent, a major gene can account for 75% and 45% of the total variability among males and females, respectively.

Adult↗
PubMed1995

Serum carotenoids and tocopherols and severity of nuclear and cortical opacities.

PURPOSE: To determine whether higher levels of individual carotenoids and tocopherols in the serum are related to less severe nuclear and cortical opacities within the general population. METHODS: Levels of individual carotenoids and tocopherols in the serum were determined in 400 randomly selected persons aged 50 to 84 years participating in the Nutritional Factors in Eye Disease Study of Beaver Dam, Wisconsin. Severity of nuclear and cortical opacities was assessed from lens slit lamp and retroillumination photographs taken at the same time. Relationships between serum levels of nutrients and prevalence of these opacities were evaluated using logistic regression analysis accounting for known possible confounders. RESULTS: Higher levels of individual or total carotenoids or alpha-tocopherol in the serum were not associated with less severe nuclear or cortical opacities overall. However, associations differed between men and women and within specific population subgroups. A significant trend for lower odds for either type of opacity with increasing levels of beta-carotene in the serum was observed in men. For nuclear sclerosis, this protective association with beta-carotene was found in younger but not older men. Higher levels of three other carotenoids (alpha-carotene, beta-cryptoxanthin, and lutein) in serum were significantly related to lower odds for nuclear sclerosis only in men who smoked. In contrast to these inverse associations observed in some subgroups, higher levels of some carotenoids and alpha-tocopherol often were directly associated with nuclear sclerosis, particularly in women. CONCLUSIONS: Higher levels of carotenoids and tocopherols are not consistently associated with less severe opacities in the general population.

Aged↗
PubMed1995

Effects of brief and prolonged ischemia on eicosanoid synthesis in dog and rat hearts.

We compared the effects of brief and prolonged myocardial ischemia on tissue prostaglandin synthesis. Regional ischemia was induced in dogs and maintained for 5 or 30 minutes. Isolated rat hearts were subjected to global ischemia in a working heart preparation for periods of 5 or 20 minutes. De novo synthesis of prostaglandins PGE2 and PGF2 alpha was measured in endocardial and epicardial explants from hearts subjected to transient ischemia. After 5 minutes of coronary ligation, PGE2 production by the ischemic canine endocardium increased by 68%, compared with non-ischemic tissue, and PGF2 alpha levels rose by 29%. In isolated rat hearts, 5-minute ischemia increased endocardial rate of PGE2 synthesis (13.2 +/- 1.7 pmol/g/h, as compared with 6.7 +/- 0.5 under normoxic conditions). Ischemic stimulation of eicosanoid production by the endocardium was no longer apparent after 30-minute regional or 20-minute global ischemia. In contrast, the epicardium showed significant changes only after 30-minute ischemia and only with respect to PGF2 alpha (12.0 +/- 6.2 in the ischemic vs 7.1 +/- 3.2 pmol/g/h in the non-ischemic tissue). Ischemia-induced differences in prostaglandin production were attenuated in the presence of arachidonic acid or aspirin.

Animals↗
PubMed1995

[An improved method for determining the mean parenchyma dose in mammography].

In mammography, it is currently assumed that the mean dose to glandular tissue DG is relevant to characterize the risk of carcinogenesis. The mean glandular dose DG results from the measured air kerma Ka at the location of the entrance surface of the breast multiplied by the conversion factors g, which usually are calculated with the help of Monte-Carlo-Simulations and which are mostly given for a standard composition of tissue (50% glandular/50% adipose tissue). By means of the signals of the double-detector of the automatic-exposure-control of the mammographic device, it is possible to obtain information about the mean composition of the breast-tissue. The knowledge of this composition enables a better calculation of the mean glandular dose DG by using conversion factors that are adapted to the tissue. This method was applied to a total of 1020 women. The comparison with the evaluation by using the conventional method shows, on average, deviations in the mean glandular dose of 9%, in specific cases the differences can be as much as 35%.

Breast↗
PubMed1995

[Depression in the child and adolescent].

Changes in criteria for Major Depression introduced in the DSM-IV will impact on the diagnosis of children and adolescents. Specifically, the new criteria are more rigorous, and the excessively high rate of Major Depression in epidemiological samples should be reduced. Atypical depression is now recognized as a distinct diagnosis. It appears to be common in adolescent depression, and its recognition should influence treatment.

Adolescent↗
PubMed1994

Retinopathy in African Americans and whites with insulin-dependent diabetes mellitus.

BACKGROUND: The development and progression of diabetic retinopathy in African Americans with insulin-dependent diabetes mellitus is not known. METHODS: Two hundred subjects with insulin-dependent diabetes mellitus with duration of diabetes 16 years or less at first visit were studied; 58 were African Americans and 142 were whites. All had gradable stereoscopic color fundus photographs (seven standard fields) from at least two visits (mean time between first and second visit was 4.1 years). Subjects with hemoglobinopathy or proliferative retinopathy or subjects who had evidence of treatment for proliferative retinopathy at first visit were excluded. Masked grading of photographs was conducted using the modified Airlie House classification scheme. RESULTS: African Americans were older, heavier, had higher systolic blood pressure (all P < .05), and marginally higher hemoglobin A1 (HbA1) values (P = .06) than the whites at first visit. African Americans had a lower rate of two steps or more progression from preexistent retinopathy (19%) than whites (43%). Progression to proliferative retinopathy or treatment was similar by race. Multivariate analysis predicting development oe progression of retinopathy, while controlling for length of follow-up, found higher HbA1 (odds ratio [OR] = 2.15), longer duration of insulin-dependent diabetes mellitus (OR = 1.69), higher serum creatinine concentration (OR = 1.59), and white race (OR = 2.62) to be independent risk factors. CONCLUSIONS: These data suggest a previously unsuspected reduction in the adjusted risk for development and progression of retinopathy in African Americans. The reason for this apparently reduced risk are not known.

Adolescent↗
PubMed1994

The association of glycemia and cause-specific mortality in a diabetic population.

BACKGROUND: The purpose of this study was to investigate the association of glycemia with cause-specific mortality in a diabetic population. METHODS: The study was a cohort design based in a primary care setting. Participants were all younger-onset diabetic persons (conditions diagnosed when they were younger than 30 years old and taking insulin, N = 1210) and a random sample of older-onset diabetic persons (conditions diagnosed when they were 30 years or older, N = 1780). Glycosylated hemoglobin levels were obtained at baseline examinations in 1980 to 1982 in which 996 younger-onset and 1370 older-onset persons participated. Median follow-up was 10 years in younger-onset and 8.3 years in older-onset persons; four younger-onset and two older-onset persons were unavailable for follow-up. The main outcome measure was cause-specific mortality as determined from death certificates. RESULTS: In the younger-onset group after controlling for other risk factors in proportional hazards models and considering underlying cause of death, glycosylated hemoglobin was significantly associated with mortality from diabetes (hazard ratio [HR] for a 1% change in glycosylated hemoglobin, 1.25; 95% confidence interval [CI], 1.13 to 1.38) and ischemic heart disease (HR, 1.18; 95% CI, 1.00 to 1.40). In the older-onset group, glycosylated hemoglobin was significantly associated with mortality from diabetes (HR, 1.32; 95% CI, 1.21 to 1.43), ischemic heart disease (HR, 1.10; 95% CI, 1.04 to 1.17), and stroke (HR, 1.17; 95% CI, 1.05 to 1.30), but not cancer (HR, 0.99; 95% CI, 0.88 to 1.10). Results for any mention of specific causes of death were similar. CONCLUSION: These results suggest possible benefit to the control of glycemia with respect to death due to vascular disease and diabetes.

Adolescent↗