Measuring and interpreting ocular blood flow and metabolism in glaucoma

There is a growing body of evidence suggesting that vascular dysfunction is related to several prominent ophthalmic diseases, including glaucoma. The vast majority of studies providing data on ocular circulation and disease pathophysiology use a relatively small number of complicated ocular blood flow imaging techniques. Although these imaging technologies are not commonly used in clinical settings, understanding the medical literature characterizing ocular blood flow requires familiarity with their methodology and function. This review highlights the imaging technologies most commonly used to investigate ocular blood flow, including color Doppler imaging, confocal scanning laser ophthalmoscopic angiography with fluorescein and indocyanine green dye, Canon laser blood flowmetry, scanning laser Doppler flowmetry, and retinal photographic oximetry. Each imaging technique's ability to define vascular function and reveal pathology is discussed as are limitations inherent to each technology. The ultimate goal of this review is to provide the physician with a clinically relevant foundation for differentiating the various ocular blood flow outcome measures often presented in the literature and determine how they are related to ocular health and disease.     

Health-related knowledge and preferences in low socio-economic kindergarteners

Objective  

The aim of the present study was to determine physical activity (PA) and nutrition knowledge and preferences in low socio-economic status kindergarten children.     

Effect of infusion of bile salts into the mesenteric artery in situ on jejunal mucosal transport function in dogs

We studied the effects of increased circulating levels of bile salts on jejunal mucosal function in dogs. In situ luminal perfusion of a 30-cm proximal jejunal segment was performed while deoxycholate, cholate, taurodeoxycholate, or taurocholate solutions were directly added to the mesenteric arterial supply, reaching the intestinal wall at successive concentrations of 5, 8, 12, and 22 mumol/L. The transport rates of water, sodium, glucose, fructose, glycine, and lysine were measured. The mucosa of the experimental loop was assayed for ATPase activity, and examined by light and electron microscopy. Deoxycholate at 8 microM in the blood supply of the perfused jejunal segment was associated with a significant (p less than 0.02) reduction in the absorption rates of water, sodium, glucose, and glycine, and inhibition of mucosal Na+, K+-ATPase. The absorption of fructose and lysine, and brush border enzyme activities, were not affected. Cholate had a similar effect at 12 microM. There were no obvious histological alterations, but electron microscopy showed swelling of mitochondria in the enterocytes. The reduction in mucosal transport, the inhibition of mucosal Na+, K+-ATPase, and the mitochondrial swelling were reversed after discontinuation of the bile salt infusion. The taurine conjugates at 22 microM depressed transport of water and sodium only, and did not inhibit Na+, K+-ATPase. Our study indicates that increased circulating concentrations of unconjugated bile salts, particularly deoxycholate, may impair Na+, K+-ATPase-related jejunal mucosal function.     

Structures of Nanoparticles Prepared from Oil-in-Water Emulsions

Hydrophobic substances were dissolved in an organic solvent and emulsified with an aqueous solution at very high shear. Droplets of very small sizes (50–100 nm) were obtained by using surfactants which were combinations of lecithins and bile salts. After emulsification, the organic solvent was removed by evaporation, yielding stable dispersions of solid particles. The sizes, shapes, and structures of the particles were examined through quasi-elastic light scattering, small-angle neutron scattering and cryotransmission electron microscopy. Cholesteryl acetate particles stabilized by lecithin and bile salts were found to be platelets of 10–20 nm thickness and 80 nm diameter. Cholesteryl acetate particles stabilized with POE-(20)-sorbitan monolaurate were dense spherical globules of diameter 100 nm. Particles with a composition similar to the endogenously occurring lipoprotein, LDL, were large spherical globules studded with small vesicles. The subsequent evolution of the Cholesteryl acetate dispersion upon aging was examined. There was no transfer of cholesteryl acetate between particles nor to large crystals. However, some aggregation of the particles was observed when the volume fraction of the particles in the aqueous dispersion exceeded 0.05. Thus, the structure of the nanoparticles obtained through deswelling of emulsion droplets changes according to the nature of the emulsifiers and to the composition of the hydrophobic substances which they contain.     

Hemisplenectomy using a hand-held CO2 laser. An experimental study

Hemisplenectomy was performed in mongrel dogs using a hand held CO2 laser. Cutting and hemostasis were performed by a laser beam with a high concentration power--about 6kW/mm2--at the focal spot, and residual bleeding was controlled by using a defocused beam. The cutting action was improved by temporary closing of the arterial vessels and by injecting adrenaline into the splenic artery to produce a relatively dry surface. The surgical procedure was free of mortality or morbidity. Histological studies revealed a brand of fibrous tissue at the cut surface, without apparent abnormalities in the splenic parenchyma beneath the section. Activity of the residual half spleen was shown by postoperative technetium scan and by the fact that Howell-Jolly bodies appeared in peripheral blood only after resection of the remaining half spleen.     

Computed tomography urography, three-dimensional computed tomography and virtual endoscopy

Spiral computed tomography technology allows an entire body region to be imaged as a continuous volume of computed tomography data. The acquisition of genitourinary images can be performed at different intervals after intravenous contrast injection in order to characterize the renal vasculature, the renal parenchyma or the collecting system. Computed tomography scanning as contrast is excreted into the collecting system is termed a 'computed tomography urogram'. Volumetric data from spiral computed tomography can be rendered into conventional two-dimensional images or even reformatted into three-dimensional views of organ systems or hollow structures, as in 'fly-through' virtual endoscopy. Although virtual endoscopy of the urinary tract remains in its infancy, three-dimensional imaging is currently a useful adjunct in the evaluation of renal transplant and donor patients and partial nephrectomy candidates. The role of computed tomography urography compared with intravenous urography in the evaluation of hematuria is discussed.     

Development of a safe oral Abeta vaccine using recombinant adeno-associated virus vector for Alzheimer's disease

A new oral vaccine for Alzheimer's disease was developed using recombinant adeno-associated virus vector carrying Abeta cDNA (AAV/Abeta). Oral administration of the vaccine without adjuvant induced the expression and secretion of Abeta1-43 or Abeta1-21 in the epithelial cell layer of the intestine in amyloid precursor protein transgenic mice. Serum antibody levels were elevated for more than six months, while T cell proliferative responses to Abeta was not detected. Brain Abeta burden was significantly decreased compared to the control without inflammatory changes. This oral AAV/Abeta vaccine seems to be promising for prevention and treatment of Alzheimer's disease.     

The maintenance of wakefulness test as a predictor of alertness in aircrew members with idiopathic hypersomnia

Aviators are required to maintain a high level of alertness during their missions. Two conditions that may disrupt this alertness are fatigue and hypersomnia. Fatigue is a physiological state, while hypersomnia is a pathologic state, also termed excessive daytime sleepiness (EDS), which is manifested by the tendency to fall asleep in inappropriate places or situations, such as during flight or driving. Hypersomnolence may be diagnosed by subjective measurements, such as the Epworth sleepiness scale, but the diagnosis is established by two objective tests: the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT). The first consists of four 20-min sessions used to determine the time it takes the patient to fall asleep when given the opportunity and is considered positive when the sleep latency time is shorter than 5 min, although some authors use 8 min as the cut-off for the diagnosis. The Maintenance of Wakefulness Test (MWT) consists of four 40-min sessions during which the patient attempts to maintain wakefulness while seated in a dark, quiet room during the day. Herein we report 2 cases of aviators who were returned to flying duty despite a pathologic MSLT. These aviators were waivered based on a normal MWT and safety history obtained from their commanders.