A new mass-culturing technique for synchronized cells is described. Continuous dilution with fresh culture medium provides the cells with nearly constant environmental conditions (continuous resupply of nutrients, constant adjustment of pH, maintenance of a nearly constant cell mass-to-culture volume ratio, etc.) at high cell densities, thereby resulting in the yield of ample cellular material for most biochemical studies during the cell cycle. The new mass-culturing system, when utilized to culture synchronous Chlorella pyrenoidosa, yielded approximately three times as much cellular material as a previous nondilution method, in the same time period and in less than one-tenth the culture volume. Although the newly developed mass-culture method was tested with a unicellular green alga, the basic method should be readily adaptable to synchronous cultures of other microorganisms and to cells in tissue culture.

Cell Division↗

PubMedDate not supplied

Effect of ethanol on amino acids and related compounds in rat plasma, heart, aorta, bronchus, and pancreas.

The composition of 36 amino acids and related amino compounds is presented for plasma, aorta, heart, pancreas, and bronchi. The distribution pattern of these biochemicals is similar but not identical among the tissues. The effect of an acute dose of ethanol (2 g/kg, i.p.) on these amino acids and related compounds was then studied. In the plasma, alanine, arginine, aspartic acid, beta-alanine, glycine, phenylalanine, and serine are decreased. In the aorta, ammonia and taurine are decreased. In the heart, aspartic acid and leucine are decreased, and carnosine, GABA, glutamic acid, and ornithine are increased. In the pancreas, asparagine and taurine are decreased, and citrulline, cysteine, histidine, and isoleucine are increased. In the bronchi, GABA, ethanolamine, histidine, taurine, and isoleucine are decreased. A number of correlations of some compounds in plasma or tissues were found but differed often between control and ethanol-treated animals. Ethanol-induced tissue changes generally do not correlate with plasma changes and are mostly specific for a given tissue.

Amino Acids↗

PubMedDate not supplied

Evaluation of equivalent efficacy of sinemet and sinemet CR in patients with Parkinson's disease applying levodopa dosage conversion formula.

We report ease of conversion, effect on equivalent efficacy and frequency of dosing when immediate-release carbidopa/levodopa (Sinemet, IR-CL, DuPont Pharma, Wilmington, DE, U.S.A.) is replaced with controlled-release carbidopa/levodopa (Sinemet CR, CR-CL, DuPont Pharma, Wilmington, DE, U.S.A.) in patients with Parkinson's disease (PD). One-step conversion through the application of a mathematical formula was utilized. Fifty-two patients (35 men, 17 women) with a mean +/- SD age of 72 +/- 8 years participated in this open-label study. All patients were taking IR-CL prior to conversion. The Unified Parkinson's Disease Rating Scale (UPDRS) was used for efficacy assessment. Pharmacokinetic studies were undertaken in five patients while they were on IR-CL, and repeated after they were switched to CR-CL. Dosage adjustment was not required either immediately after converting or during the 6-month follow-up. No significant changes occurred in efficacy scores during follow-up visits, indicating the effectiveness of the conversion. There were substantial differences in the level of plasma DOPA, dopamine, 3-O-methyldopa, homovanillic acid, and dihydroxyphenylacetic acid between patients receiving IR-CL and those receiving CR-CL, but the differences did not correlate with clinical changes, suggesting that plasma levels do not reflect tissue levels at the site of action for levodopa. This study demonstrates that conversion from IR-CL to CR-CL for optimal dosing may be achieved in one step through the application of a mathematical formula with ease of conversion and reduction of number of doses.

Adult↗