Biomedical subjects

K L Linton

Publications and source records attributed to K L Linton.

24 records · Page 2Linked to original sources

PubMed1992

Microalbuminuria in a population-based study of diabetes.

The prevalence of microalbuminuria in younger-onset diabetic participants in a large population-based study of diabetic retinopathy was determined, and the relationships of microalbuminuria to blood pressure and other risk factors were investigated. Using an agglutination inhibition test (AlbuScreen), the frequency of microalbuminuria was 21.2%. To evaluate the association of several characteristics with the presence of microalbuminuria, multivariate models based on logistic regression were developed. Microalbuminuria was associated with having higher systolic or diastolic blood pressure and higher glycosylated hemoglobin. These findings give further impetus to efforts to reduce controllable risk factors in younger-onset diabetic persons.

Adult↗

PubMed1991

The validity of self-reported and surrogate-reported cataract and age-related macular degeneration in the Beaver Dam Eye Study.

The validity of reported ocular disease was investigated in a population-based epidemiologic study of persons aged 43-86 years residing in Beaver Dam, Wisconsin. In a telephone survey conducted from September 1987 through May 1988, histories of cataract and age-related macular degeneration were obtained from the subject for 2,155 cases and from a surrogate for 1,433 cases. Within 2 years, these persons underwent a complete ocular examination. At that time, an "in-person" self-reported history of eye disease was obtained and disease presence was determined based on ocular photographs. The reporting methods, telephone versus in-person and surrogate versus subject, were compared and the validity of each assessed. Reporting methods were in agreement in better than 90% of all cases. Reporting of cataract showed a sensitivity of 20.4 for surrogate by telephone, 30.2 for self-report by telephone, and 37.8 for self-report at the examination. Sensitivity of reported age-related macular degeneration was poorer, with the highest rate of 17.9 for the "in-person" self-report. Specificity was better than 90.0 for all reporting methods for both cataract and age-related macular degeneration. These data suggest that estimates of prevalence of ocular disease should not be based solely on reported histories, and that clinical determinations are necessary.

Adult↗

PubMed1991

The Beaver Dam Eye Study: visual acuity.

Few current population-based data on visual impairment are available. Visual acuity and impairment were measured in 4926 people between the ages of 43 and 86 years in the defined population participating in the Beaver Dam Eye Study. Visual acuity was measured after refraction, using standardized protocols. Of a possible maximum score of 70 (20/10), the mean number of letters correctly identified (right eye) varied from 55.7 (20/20, n = 1515) in people between the ages of 43 and 54 years to 41.2 (20/40, n = 795) in people 75 years of age or older. Age-specific mean visual acuity scores were consistently and significantly lower in women, who identified three fewer letters on the average than men. Rates of any visual impairment (20/40 or worse in the better eye) or legal blindness (20/200 or worse in the better eye), increased from 0.8% and 0.1%, respectively, in people between the ages of 43 and 54 years to 21.1% and 2.0%, respectively, in people 75 years of age or older. Multivariate analyses showed both sex (women) and age (older) to be significant and independent predictors of poorer visual acuity.

Adult↗

PubMed1991

Pericyte changes in branch retinal vein occlusion.

The model of experimental branch vein occlusion (BVO) in the monkey offers the opportunity to examine retinal capillaries under stress. Electron microscopic morphometry was done on 812 capillaries of 13 eyes of cynomolgus monkeys, comparing 579 capillary collaterals of 9 BVO eyes with 233 normal capillaries of 4 control eyes. The tissue underwent the myosin subfragment-1 technique to decorate and quantify bundles of actin filaments in capillary pericytes. The duration of BVO was 2-48 months. Capillary collaterals of BVO eyes had an enlarged caliber, endothelial hyperplasia, and pericyte hypertrophy, but no proportional increase in basement membrane area. Collaterals near the inner plexiform layer (IPL) had a greater wall thickness, pericyte coverage, and actin coverage than collaterals near the outer plexiform layer (OPL). Pericyte hypertrophy was proportionate to caliber increase in OPL vessels and exceeded caliber increase only in IPL vessels. Actin coverage was proportional with the vessel dilation and size of pericyte cytoplasm in all vessels. These findings indicate that capillary collaterals in BVO are not equipped morphologically for an increased regulatory role in microvascular flow beyond their normal function.

Actins↗

PubMed1990

Assessment of cataracts from photographs in the Beaver Dam Eye Study.

Presence and severity of age-related cataract was determined in adults 43 to 84 years of age in Beaver Dam, Wisconsin. Duplicate photograph gradings for nuclear sclerosis (n = 1160), cortical opacities (n = 1159), and posterior subcapsular cataract (n = 1137) were performed. There are five levels of nuclear sclerosis. Exact agreement occurred in 64.7% of the cases; agreement within one category in 99.8%. For cortical opacities, graders estimate involved area in nine segments of the lens. When the continuous scale is divided into 12 categories of severity, exact agreement varied between 73.5 and 82.4%; for agreement within one category, rates varied between 84.6 and 89.9%. For posterior subcapsular cataracts, exact agreement for involvement of the central circle occurred in 95.0% and agreement within one category occurred in 97.7%. Intraobserver comparisons disclosed similar concordance. These grading schemes are semiquantitative, reproducible, and can be performed for the large numbers of photographs from population-based studies.

Adult↗

PubMedDate not supplied

Cigarette smoking and lens opacities: the Beaver Dam Eye Study.

We evaluated the relationship between cigarette smoking behavior and lens opacities in cross-sectional data on 4,926 adults in Beaver Dam, Wisconsin. The frequencies of more severe levels of nuclear sclerosis increased with packyears of cigarette smoking in women and men. For women, the odds ratio (OR) associated with 10 packyears was 1.09 (confidence interval [CI] = 1.04, 1.16) and for men it was 1.09 (CI = 1.05, 1.14) after controlling for age. The frequencies of posterior subcapsular opacities also increased in both sexes with increased packyears. The OR associated with 10 packyears of cigarette smoking was 1.06 (CI = 0.98, 1.14) for women and 1.05 (CI = 1.00, 1.11) for men after controlling for age. There was no significant effect on cortical opacities. Smoking was associated with past cataract surgery. The significant relationships of smoking with lens opacities suggest an etiologic effect. If confirmed prospectively, our results would indicate another benefit of smoking cessation.

Adult↗