Preparation and characterization of manganese dioxide impregnated resin for radionuclide pre-concentration.

An easy and reproducible preparation of manganese dioxide impregnated resin of homogeneous particles has been described. The characteristics of radium, thorium, uranium and plutonium uptake (pH dependency, kinetic studies and matrix dependency) have been determined in batch mode. The resin due to its high efficiency for radium, uranium and thorium at neutral pH values can be an effective tool for radionuclide pre-concentration from liquid samples even with high dissolved solid content.     

Raman microscopic evaluation of technology dependent structural differences in tablets containing imipramine model drug

Raman imaging method was used to characterize the effect of different manufacturing technologies on properties of the produced tablets, such as compound distribution, polymorphism, strength, and estimated active pharmaceutical ingredient (API) content. The obtained chemical maps were evaluated based on their visual appearance and on the statistical properties of the component scores obtained by direct classical least squares (DCLS) modelling. It is demonstrated that changes in the distribution of the API and excipients can be detected with chemical imaging and these differences are in close relationship with the applied granulation method and with the mechanical properties of the analyzed tablet. It is also shown that the chemical images used for characterizing the component distribution can also be processed for obtaining a cautious estimation to the mass fractions of the components.     

Regional measurements of [14C]misonidazole distribution and blood flow in subcutaneous RT-9 experimental tumors

Regional [14C]misonidazole-derived radioactivity (MISO*) was measured by quantitative autoradiography in s.c. RT-9 experimental tumors 0.5, 2, and 4 h after an i.v. bolus (25 mg) and constant infusion (10 mg/h) in rats. Misonidazole (MISO) concentration in plasma, tumor, and other tissues was also measured by high-pressure liquid chromatography. The distribution of MISO* in the tumors always resulted in a characteristic pattern with high peripheral and low central values. The high-activity regions in the tumor rim achieved tissue: plasma MISO* activity ratios of 0.97 and 2.2 by 0.5 and 4 h, respectively; for central tumor regions, this ratio was 0.20 and 0.32 for the same periods, respectively. The limited distribution of MISO* to central tumor regions could be correlated to low values of blood flow (measured with [131I]iodoantipyrine) and to diffusion from peripheral tumor regions. Low blood flow in the central regions of these tumors will significantly limit the distribution of MISO and other drugs to viable-appearing cells in these areas and could account in part for the failures of chemotherapy in certain solid tumors. Pharmacokinetic modeling indicates that 1 to 9 h may be necessary for MISO concentrations in some tumor regions to reach 50% of that in plasma.     

Comparative investigation of antipyrine half-life and induction of cytochrome P-450 dependent monooxygenases in rats treated with phenylurea herbicides

The short-term effect of three substituted phenylurea herbicides has been investigated on antipyrine plasma half-life in rats. Isoproturon was ineffective, while chlortoluron and diuron decreased the half-life significantly. There was a close correlation between antipyrine half-lives and induction of hepatic cytochrome P-450 dependent benzo(a)pyrene monooxygenase, 7-ethoxycoumarin O-deethylase and 7-ethoxyresorufin O-deethylase.     

Cerebral Effects of a Single Dose of Intravenous Vinpocetine in Chronic Stroke Patients: A PET Study

The effects of vinpocetine (Cavinton) on the cerebral glucose metabolism of chronic stroke patients are studied with positron emission tomography. The regional and global cerebral metabolic rates of glucose (C MR91 u) and the kinetic constants related to them are quantified before and after single-dose intravenous vinpocetine treatment. These measurements are completed with transcranial Doppler sonography and single photon emission computed tomography to explore the possible mechanisms underlying the resulting changes in glucose uptake and metabolism in the brain. The authors' findings indicate that a singledose vinpocetine treatment, although it does not affect significantly the regional or global metabolic rates of glucose, improves significantly the transport of glucose (both uptake and release) through the blood-brain barrier in the whole brain, the entire contralateral hemisphere, and in the brain tissue around the infarct area of the symptomatic hemisphere. These changes are in accord with increased blood flow in the entire contralateral hemisphere as well as decreased blood flow velocity and increased peripheral vessel resistance in the entire symptomatic hemisphere.     

Electrical cataract and optic neuropathy

We report on a 20 year old male, who developed mature cataract (Electrical Cataract) on both eyes after a severe electric shock from high voltage. Both of his hands and the left foot had to be amputated, because of the severe injury. Although electrical cataract due to high voltage or lightning is rare, they may still occur after industrial or home electric accidents. Even if extracapsular cataract extraction with intraocular lens implantation is successfully performed, the final visual acuity will depend on other ocular damage due to the electric current.