Natural course of retinitis pigmentosa over a three-year interval

Ninety-four patients, 6 to 49 years old, with progressive forms of retinitis pigmentosa were examined at baseline and annually for three consecutive years with respect to visual acuity, kinetic visual fields, dark-adaptation thresholds, computer-averaged electroretinograms, and fundus photographs. A subset was recalled within two months of a given visit to measure intervisit variability and to develop criteria for what constitutes significant (P less than .01) functional change. Over a three-year interval full-field electroretinograms declined significantly in 66 of 86 patients (77%) with detectable responses at baseline. Patients lost an average of 16% to 18.5% of remaining electroretinographic amplitude per year and 4.6% of remaining visual field area per year. Bone spicule pigmentation increased in 41 of 76 patients for whom we could make comparisons over a three-year interval (54%). Visual acuity and dark-adaptation thresholds remained relatively stable.     

Social support and quitting smoking for good. Is there an association? Results from the population study, "Men born in 1914," Malm?, Sweden

The objective in this study was to analyse whether there is independent association between social network, social support, social influence and quitting smoking for good. The study sample (n = 621) comprised a random half of all male Malm? residents born in 1914, of which 500 (80.5%) participated. A new instrument based on a model with carefully defined and well differentiated concepts was used to measure different aspects of social network, social support and social influence. In logistic regression analysis, emotional support (an important aspect of social support) had an association to quitting smoking for good (odds ratio 3.1, 95% confidence interval 1.9-5.4), when adjustments were made for social class, marital status (spousal support), alcohol consumption, physical activity, smoking of spouse and different medical conditions. Emotional support reflects the individuals' opportunity for care, encouragement of personal value and feelings of confidence and trust. This may contribute to a deeper understanding of mechanisms behind smoking cessation and could be of importance in the field of health promotion, but also for improvement of the long-term results of smoking cessation programs and in our clinical work with patients who smoke.     

Effects of non-steroidal anti-inflammatory drugs on lymphocyte activation

Guinea-pig lymph node lymphocytes were stimulated with mitogen (phytohaemagglutinin)in vitro and lymphocyte activation was measured by tritiated thymidine incorporation (DNA synthesis). Inclusion of non-steroidal anti-inflammatory drugs (NSAIDs) in the culture medium at therapeutic concentrations, frequently exerted an inhibitory effect. Such inhibition could be not attributed to the ability of these drugs to inhibit cyclo-oxygenase or lipoxygenase enzymes. Inhibition by salicylates was not associated with cytotoxic or cytopathic effects, since inhibition was only evident when the drugs were included in the early phase of culture. Other NSAIDs exhibited varying degrees of toxicity, which in some instances may account for observed inhibition. The effects on lymphocyte activation of selective inhibitors of pathways of arachidonic acid metabolism, do not support the proposition that the generation of prostaglandins, thromboxanes, leukotrienes or related compounds is an obligatory step during lymphocyte activation.     

Estimation of body composition from anthropometric and physiological measurements of obese college women

Relationships between anthropometric and physiological measurements and body composition were examined in 42 obese college women. Estimates of body density (BD), fat weight (FW), and fat free weight (FFW) were obtained by the helium dilution method. Anthropometric measurements included height, weight, 4 body diameters, 4 body girths, hand grip strengths, and 7 skinfold thicknesses; physiological measurements were daily urinary creatinine and basal metabolic rate. Simple correlation coefficients between each of these measurements and the estimates of body composition were less than 0.7, indicating little predictive accuracy from single measurements. Multiple correlation coefficients (R) were higher for FW (R=0.83 to 0.88) than for BD (R=0.64 to 0.75) or FFW (R=0.72 to 0.80). The equations that most accurately estimated body composition included skinfold thickness, hand grip strength, basal metabolic rate, and a variable calculated from height and weight. When equations selected from the literature were used, BD and FFW were consistently overestimated and FW underestimated.     

EFFECT OF INCREASED BILE FLOW AND BILE ACID SECRETION ON THE HEPATIC ELIMINATION OF SODIUM VALPROATE IN THE CAT

The effect of increased bile flow and hepatic bile acid flux on the systemic clearance and hepatic elimination of intravenously administered sodium valproate was studied in the bile fistula cat. Taurochenodeoxycholic acid (TCDC), tauro-3 alpha, 7 beta-dihydroxy-12-keto-5 beta-cholanoic acid (T12K), SC-2644, and secretin were infused intravenously to vary bile flow and biliary bile acid secretion. Control animals were infused with 0.15 mol/l NaCl. Less than 1% of the drug administered to controls appeared as unchanged valproate in the bile over 6 h. Although SC-2644, T12K, and secretin significantly increased biliary excretion of valproate, it did not exceed 2% of the intravenous dose. Biliary clearance was directly related to the rate of bile flow, but not to the bile acid flux. By contrast, 18-19% of the dose appeared in bile as metabolite in controls, and none of the choleretic agents significantly increased this percentage. As a result, systemic clearance of valproate was unaltered. We conclude that the movement of unchanged valproate into bile is consistent with a process of simple diffusion. The fact that choleretic agents do not increase metabolite excretion into bile suggests that metabolite formation may be the rate-limiting step in the hepatic elimination of valproate, rather than transport and excretion of metabolites into bile.     

Durability of confluent endothelial cell monolayers on small-caliber vascular prostheses in vitro

Since implantation of small-caliber vascular grafts with preformed confluent endothelial cell monolayers (ECMs) may prevent acute platelet deposition and thrombus formation, we have evaluated the conditions necessary to produce durable ECMs. Cultured human umbilical-vein ECs in buffer were attached to vascular grafts--either expanded polytetrafluoroethylene (ePTFE) or knitted Dacron, both with inside diameters of 4 mm--precoated with collaten type I and perfused in vitro with serum-containing culture medium to achieve cell spreading into confluent monolayers. The number of cells attached was quantified by DNA measurements and indium-111 labeling. Morphology was evaluated by scanning electron microscopy. The maximum number of cells that attached acutely was 3.6 X 10(5) cells/cm2 graft, and the minimum number needed for confluence was 1.4 X 10(5) cells/cm2 graft. Confluence was morphologically complete after 2 hours of in vitro perfusion at 15 ml/min. When ECMs were exposed to varying flow rates, cell retention after 1 hour was 96.1% +/- 5.6% at 50 ml/min, 94.6% +/- 6.1% at 100 ml/min, 77.6% +/- 10.8% at 200 ml/min (p less than 0.001), and 40.1% +/- 10.4% at 400 ml/min (p less than 0.0001). Confluence was maintained for all grafts exposed to flows of 100 ml/min or less. Fewer cells were retained when acutely attached, unspread cells (71.5% +/- 11.5%) were compared with established ECMs (89.9% +/- 6.7%) at a flow rate of 100 ml/min (p less than 0.0001). ECMs on knitted Dacron were more durable than on ePTFE (82.7% +/- 5.3% versus 75.5% +/- 4.8% remained attached at 200 ml/min, P less than 0.05). 111Indium-labeled and unlabeled cells were equivalent with respect to saturation level attachment, spreading time to confluence, and durability under flow at 100 ml/min. We conclude that confluent and durable endothelial cell monolayers can be established on small-caliber vascular grafts within 2 hours.