Using hydrofluoroether solvents to replace HCFC-141b, Part II.

The use of hydrochlorofluocarbon (HFC) solvents is banned from the end of 2001. Part of this article assessed the merits of using hydrofluoroethers as replacement solvents. Alternatives to HFCs are more expensive. Part II looks at how to reduce the cost of conversion.

Using hydrofluoroether solvents to replace HCFC-141b, Part I.

Hydrochlorofluorocarbon solvents have been used for a variety of applications, including silicone deposition, precision cleaning, drying and tube swelling. Their use in these applications is banned in Europe from the end of 2001. Part I of this article explores the technical merits of replacement solvents, with particular reference to hydrofluoroethers.

Advice on healthy food as given by Flemish general practitioners.

I report on a search of international and Belgian literature for publications about nutritional work in general practice. I found little information. Reports on four local actions were found, focusing on cardiovascular disease, diabetes, or increasing fiber intake. Universities should be stimulated to pay more time and attention both to knowledge about foods and to training on how to give nutritional advice. The lesson on healthy food developed with dietitians for the Flemish Institute for Continued Medical Education needs more support.

The thyroxine-stimulating activity is only present in the glycoprotein and not in the protein fraction of a carp hypophyseal homogenate.

The in vivo release of thyroxine (T4) in the carp (Cyprinus carpio) and the in vitro release of T4 in the frog (Rana ridibunda) from isolated thyroids were used as a bioassay to study the thyrotropic activity of carp hypophyses. The addition of up to 1 hypophyseal equivalent to the medium did not increase the in vitro release of T4 from isolated frog thyroids in November whereas 3 mU of bovine thyrotropin (b-TSH) was effective. However, when this experiment was repeated at the end of February, the responsiveness of frog thyroids was increased since the addition of 0.5 carp hypophyseal equivalent did stimulate the release of T4. When Winter carp alone were used in an in vivo bioassay, an intracardial injection of up to a dilution of 1/64 hypophyseal equivalent increased plasma concentrations of T4 after 2 and 4 hr. However, 3 mU of b-TSH was ineffective in this regard. Affinity chromatography of b-TSH indicated that all thyrotropic activity as tested in the frog bioassay was retained on a concanavalin (Con A)-Sepharose column. Following Con A separation of a carp hypophyseal homogenate it was finally demonstrated that the unadsorbed protein fractions did not increase plasma concentrations of T4, whereas the adsorbed glycoprotein fraction did. No influence on circulating triiodothyronine (T3) levels was noted with both fractions. These results indicate that the thyrotropic activity of a carp hypophysis is of a glycoprotein nature.