Increased dependence on visual information for movement control in patients with Parkinson's disease

Studies were made of visually and non-visually guided movements by patients with Parkinson's disease. The subjects moved a light, horizontal handle using rotation primarily about the elbow. During visually guided trials both handle and target positions were displayed to the subject; during non-visually guided trials only the handle position was displayed. During non-visually guided trials all patients showed a tendency for an overall flexion drift, although there was no change in average movement amplitude. The overall error in position by the end of the non-visually guided trials was greatly in excess of the reported values for passive displacement thresholds in normal subjects. It is suggested that the data indicate an increased dependence on visual information for control of motor activity in Parkinson's patients.     

Use of different concentrations of carbamide peroxide for bleaching teeth: an in vitro study

OBJECTIVE: This in vitro study compared the shade changes in extracted teeth during 2 weeks' whitening with 5%, 10%, or 16% carbamide peroxide. METHOD AND MATERIALS: After color calibration, the sole examiner selected 110 extracted unrestored, noncarious teeth, shade A3 or darker on a value-oriented guide. The teeth were randomly distributed into equal color groups. The control group (11 teeth) was treated with 0.9% saline, while the experimental groups (33 teeth each) were treated with 5%, 10%, or 16% carbamide peroxide. The solutions remained on the teeth for 8 hours. The teeth and tray were rinsed with tap water for 2 minutes, then rehydrated in 0.9% saline for 16 hours in the humidifier. The shade was assessed, and the process was repeated daily for 2 weeks. RESULTS: Repeated-measures analysis of variance indicated a significant difference in overall shade values between the control and all carbamide peroxide-treated groups at days 8 and 15. A Kaplan-Meier Survival Analysis indicated a quicker two-tab color change for the 10% and 16% groups than the 5% group. However, continuation of the 5% treatment to 3 weeks resulted in shades that approached the 2-week 10% and 16% values. CONCLUSION: Lower concentrations of carbamide peroxide take longer to whitening teeth but eventually achieve the same result as higher concentrations. Higher concentrations may cause increased sensitivity.     

Interactions of the invasive pathogens Salmonella typhimurium, Listeria monocytogenes, and Shigella flexneri with M cells and murine Peyer's patches

Invasive enteric bacteria must pass through the intestinal epithelium in order to establish infection. It is becoming clear that a common target for intestinal mucosa penetration is the specialized epithelial cell of Peyer's patches, the M cell. In order to gain a better understanding of how bacteria interact with M cells, we have compared the interactions of Salmonella typhimurium, Listeria monocytogenes, and Shigella flexneri with M cells by using a murine ligated-loop model. Our results indicate that S. typhimurium possesses a highly efficient mechanism for M cell entry that targets and destroys these cells, while L. monocytogenes and S. flexneri appear to be internalized into M cells in a less disruptive fashion. Early uptake of Listeria or Shigella into M cells appeared to lead to the death of some cells, as evidenced by the appearance of holes in the intestinal epithelium. At later time points, the follicle-associated epithelium of animals infected with these bacteria displayed extensive destruction. These data indicate that enteric pathogens use different strategies to interact with M cells and initiate infection of a host.     

The principles of administering drug and non-drug treatment methods in peptic ulcer

As the result of the study optimal schemes of the ulcer disease treatment were elaborated. They include microwave resonance therapy, immunomodulatory and antibacterial drugs with regard to localisation, depth and size of the ulcerous lesion, exacerbation rate, degree of secondary immune disorders and seeding of gastric mucosa with Helicobacter pylori. The treatment suggested allows to shorten the terms of ulcer cicatrization, reduces exacerbation rate and ensures clinico-endoscopic remission in most patients with ulcer disease.     

Solid-state NMR studies of magnetically aligned phospholipid membranes: taming lanthanides for membrane protein studies

The addition of lanthanides (Tm3+, Yb3+, Er3+, or Eu3+) to a solution of long-chain phospholipids such as dimyristoylphosphatidylcholine (DMPC) and short-chain phospholipids such as dihexanoylphosphatidylcholine (DHPC) is known to result in a bilayer phase in which the average bilayer normal aligns parallel to an applied magnetic field. Lanthanide-doped bilayers have enormous potential for the study of membrane proteins by solid-state NMR, low-angle diffraction, and a variety of optical spectroscopic techniques. However, the addition of lanthanides poses certain challenges to the NMR spectroscopist: coexistence of an isotropic phase and hysteresis effects, direct binding of the paramagnetic ion to the peptide or protein of interest, and severe paramagnetic shifts and line broadening. Lower water concentrations and larger DMPC/DHPC ratios than those typically used in bicelles consistently yield a single oriented bilayer phase that is stable over a wide range of temperature (approximately 35-90 degrees C). Among the above choice of lanthanides, Yb3+ is found to give minimal paramagnetic shifts and line broadening at acceptably low concentrations necessary for alignment (i.e., Yb3+/DMPC mole ratios equal to or greater than 0.01). Finally, the addition of a phospholipid chelate, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine--diethylenetriaminepent aacetic acid, is observed to significantly reduce paramagnetic broadening and presumably prevent direct association of the peptide with the lanthanide ions.     

Regression of morphological alterations and oxidative stress-related parameters after acute lindane-induced hepatotoxicity in rats

Changes in rat liver oxidative stress-related parameters, morphological alterations, as well as circulating and tissue levels of lindane were studied 1-7 days after the administration of a single dose of 60 mg of lindane/kg. One day after lindane treatment, a significant enhancement in the oxidative stress status of the liver was observed, characterized by an increase in thiobarbituric acid reactants production and in the microsomal generation of superoxide radical (O.-2) coupled to cytochrome P450 induction, and a decrement in the activity of superoxide dismutase (SOD) and catalase. Consequently, the O.-2 production/SOD activity ratio was enhanced two-fold. In this condition, light microscopy studies revealed the incidence of liver lesions in periportal areas, together with significant changes at the mitochondrial level observed by electron microscopy, which coincide with the maximal levels of lindane in the liver, adipose tissue, plasma and whole blood. Changes in oxidative stress-related parameters observed after 1 day of lindane treatment regressed to normal from the third day and thereafter, together with the decrement in circulating and tissue levels of the insecticide. It is concluded that morphological and oxidative stress-related changes induced in the liver by acute lindane intoxication are readily reversible, depend on the hepatic content of the insecticide, and seem to be conditioned by the changes in O.-2 generation.     

Electron spectroscopic imaging analyses of the distribution of phosphorus in Balbiani ring granules and in the surrounding nucleoplasm

When they were introduced to the world market in the 1980s, levonorgestrel subdermal implants offered the promise of an exciting alternative to traditional hormonal contraception. They provide highly effective, long-acting protection from pregnancy, without the need for user compliance. Broad acceptability of the drug has been reported throughout the world. Recently, however, the implants have met with opposition. The drug is associated with a variety of adverse effects, and removal of implants can be problematic. Serious events have been reported in women using levonorgestrel subdermal implants, although causal relationships have not been demonstrated. Additionally, concerns have been raised over the potential for coercive use of the drug. Numerous law suits have been filed alleging serious problems with implants. As a result, the drug has received considerable negative media attention. Before the controversy over levonorgestrel subdermal implants erupted, contraceptive development had declined, resulting from limitations to profits and funding, legal threats, and changes in the insurance industry. The levonorgestrel subdermal implant experience may serve to accelerate this trend. While the introduction of levonorgestrel subdermal implants offered an alternative to the current array of medical contraception, its experience may serve to dampen future contraceptive development efforts. Costly litigation and much controversy involving the implants have acted to create disincentives to further research and development of new methods of medical contraception.