Biomedical subjects

D L Hom

Publications and source records attributed to D L Hom.

25 records · Page 2Linked to original sources

PubMed1990

An in vitro and clinical comparison of corneal storage with chondroitin sulfate corneal storage medium with and without dextran.

The safety and efficacy of 1% dextran in Chondroitin Sulfate Corneal Storage Medium (CSM) in reducing corneal swelling after 4 degrees C storage was assessed in a corneal endothelial cell culture system. No difference was found in 3H-thymidine incorporation by cells incubated in either CSM-dextran medium or CSM medium alone. Subsequently, 21 pairs of corneas, stored in either CSM or CSM-dextran from 30 to 112 hours, were transplanted into 42 eyes of 42 patients, paired by diagnostic group and procedure. All CSM grafts and 19 of 21 CSM-dextran grafts were clear at 4 months with no primary donor failures in either group. Intraoperative corneal thickness was significantly greater in the CSM group (0.82 +/- 0.07 mm) than the CSM-dextran group (0.76 +/- 0.06 mm); however, the two groups did not differ thereafter. No differences in all endothelial morphometric parameters were noted between the two groups pre- and postoperatively. Average endothelial cell loss by 4 months was 13.0 +/- 16.4% for the CSM group and 16.4 +/- 15.5% for the CSM-dextran group. The addition of dextran to CSM medium results in significant intraoperative corneal thinning without adversely affecting endothelial DNA synthesis in vitro and endothelial survival in vivo.

Adult↗

PubMed1990

Correlation between nasal width and maxillary incisal alveolar width in post-natal facial development.

The paired nasomedial processes of the prenatal developing face contribute to the formation of the nasal region as well as the alveolar segment of the maxillary four incisors. The objective of this investigation was to determine whether or not there is a common anatomic relationship between the transverse nasal dimension and the corresponding transverse alveolar dimension that is continued in the post-natal period. The corresponding transverse dimensions were measured on a longitudinal series of 120 A-P cephalograms. In addition, A-P cephalograms of 24 dried skulls and also of 19 individuals having severe craniofacial malformations were analysed. The mean difference between the nasal dimensions and the corresponding alveolar dimensions ranged from 0.14 to 1.72 mm in the various groups. However, the statistically significant correlation coefficients between the measured dimensions were low (range r = 0.36-0.57). The developmental stage did not affect this relationship. Crowding was not found to be a major factor explaining the variability, although sex was seen as a significant factor.

Adolescent↗

PubMed1989

The bleeding severity index: validation and comparison to other methods for classifying bleeding complications of medical therapy.

Reports of bleeding complications of medical therapy should be based on valid methods of classification, but the reproducibility of existing methods has not been tested. Therefore, we prospectively studied three methods to classify the severity of bleeding: a purely subjective implicit method, a previously published explicit method using brief criteria, and the bleeding severity index, which is a new explicit method using detailed criteria about the amount, rate, and consequences of bleeding. Three physicians independently reviewed abstracts of 168 patients treated with anticoagulants. The proportion of cases classified as major bleeding varied widely when the implicit method was used (2, 14 and 39%), less when the old explicit method was used (28, 40 and 47%), and not at all when the new bleeding severity index was used (20, 20 and 20%). Intraobserver agreement was excellent for both explicit methods (kappa greater than or equal to 0.95). However, interobserver agreement was better for the bleeding severity index (kappa = 0.87) than for the old explicit method (kappa = 0.69) or the implicit method (kappa = 0.39). We conclude that the classification of bleeding complications of medical therapy depends on the method used. In comparison to older methods, the bleeding severity index is highly reproducible and should be tested more widely to determine whether it can be applied to the burgeoning clinical research in anticoagulation and thrombolysis.

Anticoagulants↗

PubMed1988

The assessment of historical physical activity and its relation to adult bone parameters.

The aim of the present research was to determine the association between historical physical activity and baseline bone measurements in a group of 223 postmenopausal women participating in a clinical trial in Pittsburgh, Pennsylvania, from 1981 to 1986 by evaluating the effect of moderate physical activity on bone loss. Historical physical activity was assessed by a survey which divided the life span into four time periods (14-21, 22-34, 35-50, and 50+ years) and inquired about participation in leisure time physical activities for each period. From the responses, kilocalories of energy expenditure were calculated. Cortical bone density and area were measured in the radius with a computerized tomography scanner. The historical physical activity survey was administered a second time two to three months after the initial test to a 10% random sample of the women in order to determine the test-retest reliability of the instrument. Since the measurements of historical physical activity proved to be reliable, estimates of kilocalories determined for the entire population of women were correlated with bone area and density. A significant relation was found to exist between historical physical activity and dimensions of adult bone, particularly bone area. This association remained significant after adjustment for potential confounding variables and seemed to be strongest in the earlier age periods. To the authors' knowledge, this is the first report of a significant association between historical physical activity and bone.

Energy Metabolism↗

PubMed1987

The effects of walking on the cross-sectional dimensions of the radius in postmenopausal women.

This report deals with the analysis of data from a 3-year clinical trial on the effect of walking on postmenopausal bone loss. Two hundred fifty-five women, with an average age of 57 at entry, were randomized into two groups, a walking and a control group. Bone measures in the shaft of the radius were carried out with a CT scanner in search of generalized skeletal effects rather than effects localized to the bones of the leg. Although bone density losses were comparable in the two randomized groups, changes in the cross-sectional area of the radius were significantly greater in the walkers with high grip strength (greater than 25 Kg) than in the controls with comparable high grip strength which corresponded to the upper half range of the grip-strength distribution. It is concluded that the moderate activity of walking exerted systemically positive effects on the radius which, within the protocol of the study, could be substantiated only when synergized with inherent muscle strength.

Female↗

PubMed1986

Lipoprotein cholesterol, vitamin A, and vitamin E in an alcoholic population.

Elevated alcohol consumption is associated with an increased risk of cancer. Reasons for this association are not well established but may relate to alterations in cholesterol, vitamin A (carotene and retinol), and vitamin E metabolism, since low levels of these factors have been linked to risk of cancer. Blood levels of cholesterol, carotene, retinol, and vitamin E were determined in 192 male alcoholics entering into an alcohol detoxification program. Compared to nonalcoholic populations, their cholesterol (187 mg/dl) and carotene (94 micrograms/dl) concentrations were markedly reduced at entrance; however, abstinence of 33 days returned both to normal levels. In contrast, the retinol and vitamin E levels were within the normal range at baseline and remained relatively stable throughout rehabilitation. Of particular interest was that the low density lipoprotein cholesterol was highly correlated with carotene (r = +0.40, whites, r = +0.54, blacks). The results suggest that alterations in the metabolism of cholesterol and carotene, due to alcohol intake, may partially account for the relationship of alcohol to increased cancer risk.

Alcoholism↗

PubMed1985

Alcohol consumption and high density lipoprotein cholesterol concentration among alcoholics.

Alcohol consumption is one of the major determinants of serum high density lipoprotein (HDL) cholesterol. Very few studies have examined the correlation between alcohol consumption and high density lipoprotein subclasses. It has been suggested that HDL2 is probably the fraction that is associated with reduced coronary heart disease. The current research investigated the relationship between alcohol consumption and HDL2 and HDL3 cholesterol among 234 alcoholics who were admitted for abstinence. The results indicated that the elevated serum HDL cholesterol concentrations among alcoholics were a combination of an increase in both HDL2 and HDL3 cholesterol. HDL cholesterol and HDL2 cholesterol increased with more alcohol consumption until about 450 ml of ethanol consumption per day when serum HDL cholesterol and HDL2 cholesterol decreased. HDL3 cholesterol showed a similar trend but was not statistically significant. In addition, the serum concentrations of HDL cholesterol and subclasses were positively correlated with liver enzymes. Those with alcohol-related liver disease had significantly higher HDL and HDL2 cholesterol levels than those without. Both HDL cholesterol and subclasses decreased concomitantly with the decline in liver enzymes within one month of abstinence. The possible biologic mechanisms linking alcohol drinking with HDL cholesterol through liver induction and sex hormone changes are discussed.

Adolescent↗