Comparison of the eye's wave-front aberration measured psychophysically and with the Shack-Hartmann wave-front sensor

The Shack-Hartmann wave-front sensor offers many theoretical advantages over other methods for measuring aberrations of the eye; therefore it is essential that its accuracy be thoroughly tested. We assessed the accuracy of a Shack-Hartmann sensor by directly comparing its measured wave-front aberration function with that obtained by the Smirnov psychophysical method for the same eyes. Wave-front profiles measured by the two methods agreed closely in terms of shape and magnitude with rms differences of approximately lambda/2 and approximately lambda/6 (5.6-mm pupil) for two eyes. Primary spherical aberration was dominant in these profiles, and, in one subject, secondary coma was opposite in sign to primary coma, thereby canceling its effect. Discovery of an unusual, subtle wave-front anomaly in one individual further demonstrated the accuracy and sensitivity of the Shack-Hartmann wave-front sensor for measuring the optical quality of the human eye.     

Microcirculatory bed of the rat ovary in health and under laser irradiation

Personal clinical observations during the recent years allow the authors to confirm the indisputable value of surgical experience got during the Great Patriotic War (1941-1945) and in particular, the "fourfold" scheme proposed by V. I. Voiachek for the diagnosis and treatment of blind gunshot wounds to the skull base. Computed tomography considerably increases the probability of detection of the exact localization of foreign bodies in complex anatomical structures of the skull and thus facilitates choosing the most rational surgical management. The use of the electro-optical transducer for the extraction of foreign bodies from almost inaccessible areas of the skull base decreases the risk of operation.     

Acuity perimetry and the sampling theory of visual resolution

In fura-2-labelled human platelets, the thiol oxidising agent diamide decreases the intracellular calcium response to thrombin and serotonin without affecting the basal calcium levels. The effect of diamide on the thrombin response could be prevented by pre-treatment with dithiothreitol (DTT) and reduced when DTT was added 60 s after diamide. The effects of diamide and hydrogen peroxide on the thrombin response were additive. Hydrogen peroxide also produced a calcium response per se, but this response was not affected by diamide. Hydrogen peroxide increased rat brain phosphoinositide hydrolysis and reduced the response to carbachol and noradrenaline, whereas diamide was without effect. The binding of [3H]inositol-1,4,5-trisphosphate to human platelet membranes was inhibited by diamide but not by hydrogen peroxide. Thus diamide affects the phosphoinositide signal transduction pathway in a qualitatively different manner from that found with hydrogen peroxide. It is suggested that oxidative stress may contribute to the disturbances in the phosphoinositide transduction pathway that are found in Alzheimer's disease.     

Effects of aging, diet, and sex on plasma glucose, fructosamine, and lipid concentrations in barrier-raised Fischer 344 rats

We studied the relationships of plasma glucose, fructosamine, triglycerides, and cholesterol as a function of age, gender, and diet in barrier-raised Fischer 344 rats aged 5 to 26 months, fed a diet either ad libitum or restricted to 60% of the ad libitum caloric intake. The complex relationships of these plasma levels to age, gender, and diet led to the development of a model with age, diet, and sex as covariates. Overall, fasting plasma glucose concentrations were reduced by approximately 25% in rats on the restricted diet, compared to ad libitum-fed animals. There was a significant age-dependent decline in glucose levels in male animals, whereas in females there was an increase in plasma glucose with aging. Plasma fructosamine levels in calorie-restricted animals, overall, were reduced by 7% compared to levels in animals fed ad libitum. There was a significant positive correlation between plasma glucose and fructosamine levels. Mean plasma triglyceride content was decreased by 50% in calorie-restricted rats compared to ad libitum-fed animals. A significant decrease in triglyceride levels with increasing age was seen in male animals, and an increase with aging in females. There was a significant positive correlation between plasma glucose and triglyceride levels. Plasma cholesterol levels in calorie-restricted animals were reduced by 7% compared to levels in ad libitum-fed animals. An increase of cholesterol concentration with aging was significant in both males and females. Analysis of the data showed that there were significant differences between male and female Fischer 344 rats in the response of plasma glucose and fructosamine to aging and calorie restriction. Changes of plasma triglyceride and cholesterol with aging and dietary calorie restriction were also different in males and females. Studies of the effect of aging on glycemia and blood lipid content should take into account the contributions of animal sex.