Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Caudate nucleus volume and cognitive performance: Are they related in childhood psychopathology?

BACKGROUND: Impaired neuropsychological test performance, especially on tests of executive function and attention, is often seen in children diagnosed with autism spectrum disorders (ASD). Structures involved in fronto-striatal circuitry, such as the caudate nucleus, may support these cognitive abilities. However, few studies have examined caudate volumes specifically in children with ASD, or correlated caudate volumes to cognitive ability. METHODS: Neuropsychological test scores and caudate volumes of children with ASD were compared to those of children with bipolar disorder (BD) and of typically developing (TD) children. The relationship between test performance and caudate volumes was analyzed. RESULTS: The ASD group displayed larger right and left caudate volumes, and modest executive deficits, compared to TD controls. While caudate volume inversely predicted performance on the Wisconsin Card Sorting Test in all participants, it differentially predicted performance on measures of attention across the ASD, BD and TD groups. CONCLUSIONS: Larger caudate volumes were related to impaired problem solving. On a test of attention, larger left caudate volumes predicted increased impulsivity and more omission errors in the ASD group as compared to the TD group, however smaller volume predicted poorer discriminant responding as compared to the BD group.     

Modulation of mouse mammary tumor growth and linoleate enhanced metastasis by oleate

This study examines whether oleate may influence the linoleate enhanced metastasis of line 4526 murine mammary tumors. In addition, the in vitro proliferative response of line 4526 to oleate and other selected fatty acids was assessed. Initially, the tumor cells were grown in a defined medium supplemented with palmitate, stearate, oleate, linoleate, linolenate or arachidonate. The unsaturated fatty acids stimulated and the saturated fatty acids inhibited proliferation compared to fatty acid-free medium. Next, we examined the effect of oleate on the linoleate enhanced metastasis of 4526 tumors by substituting oleate for saturated fat in isoenergetic diets containing high or low levels of linoleate. Oleate had no effect on metastasis in mice fed the high linoleate diets but it significantly increased metastasis in mice fed the low linoleate diets. Finally, the fatty acid compositions of tumors and mammary fat pads were compared to diet fatty acid compositions and metastatic frequency. Metastasis corresponded more closely to total unsaturated fatty acids than to total polyunsaturated fatty acids or to any individual fatty acid. These studies suggest that both mono- and polyunsaturated fatty acids may stimulate mammary tumor metastasis. However, the influence of dietary oleate probably depends on the level of linoleate and total unsaturated fatty acids in the diet.     

Platelet activating factor as a proinflammatory mediator in acetic-induced colitis in the rat

The nature of histamine receptors in peripheral tissues is still controversial. However, evidence of heterogeneous classes of binding sites for [³H]-mepyramine are reported in the literature. The aim of our study was, therefore, to investigate the nature of this heterogeneity by comparing [³H]-mepyramine study was, therefore, to investigate the nature of this heterogeneity by comparing [³H]-mepyramine binding in a central tissue (cerebellum) and in a peripheral tissue (lung) obtained from guinea pigs and to assess its dependence upon the temperature of incubation. The results revealed that the [³H]-mepyramine interaction in both tissues is temperature-dependent. At 25°C, the interaction between [³H]-mepyramine and the receptors was biphasic in the lung while only a single class of binding site was found in the cerebellum. At 0°C, [³H]-mepyramine interacted with three binding sites in the lung and two in the cerebellum. The behaviour of the reference compounds (clemastine, promethazine and histamine) also supported this temperature-dependence. Moreover, two new compounds (DF 11062 and DF 11113), synthesized in our laboratories and endowed with antihistamine activity, can differentiate between the low affinity site seen at 25°C in the lung and that seen in the cerebellum at 0°C.     

William Cowper

William Cowper, now virtually forgotten, was the first of the surgeon-scientists of Great Britain. He was the first to bring the power of the experimental method to bear on practical surgical problems and to urge that the principles of surgery be drawn from an understanding of the "animal oeconomy." In these areas he anticipated the celebrated Hunterian school of surgery by more than half a century and by his example he actually set the foundation on which that school was built. Cowper was a scientist of a high order. He was the first to prove the existence of capillaries in higher mammals, to describe naturally occurring arteriovenous shunts in the lungs and spleen, to define the essential physiology of aortic valvular disease, and to recognize the nature and consequences of arteriosclerotic vascular disease. He was the author of two important anatomy books and the first English language treatise on general physiology available to surgeons. He was one of the first two surgeons ever honored by election to the prestigious Royal Society of London. An analysis of the works and doctrines of William Cowper appears to cast serious doubt on the common teaching that the idea of "scientific surgery" was the sole creation of John Hunter.     

Clozapine for refractory schizophrenia: the Illinois experience

Based upon the Illinois Department of Mental Health and Developmental Disabilities' computerized clinical information system, with its integration of client-specific clinical data, a 5-year retrospective study was designed to determine the clinical effectiveness and economic impact of the use of clozapine for treatment-resistant schizophrenia. The study sample consisted of 518 hospitalized, treatment-resistant patients. At the end of 5 years, 78% were well maintained on clozapine. Two hundred forty-three patients had been discharged to the community, and 62 had been transferred for treatment of medical or surgical problems. Clozapine treatment was discontinued in 115 patients (22%). The drug was well tolerated, with a very low incidence of agranulocytosis. Cost savings resulting from the discharge of the 243 clozapine-treated patients amounts to approximately $20 million per year. A disease management algorithm has been developed allowing physicians to begin clozapine treatment for patients not successfully treated with 2 prior antipsychotic agents. Adherence to this protocol throughout the state's mental health system would result in even greater savings.     

The vasa vasorum and angioplasty

Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.