Resistance of the red poultry mite to pyrethroids in France.

The resistance of Dermanyssus gallinae, the red poultry mite, to a pyrethroid acaricide, permethrin, and to an organophosphate, dichlorvos, was examined on five French poultry farms which had experienced problems in controlling mite populations and on one farm with no problems. The concentration of permethrin required to kill 50 per cent of the mites on the five farms was between eight and 40 times the concentration required on the control farm. In contrast, no resistance to dichlorvos was detected. This is the first description of resistance to a pyrethroid in D gallinae in France.

[Appearance and metabolic development of diabetes mellitus in the sand rat, Psammomys obesus]. / Apparition et évolution métabolique du diabète sucré chez le rat des sables, Psammomys obesus.

The aim of this study was to examine the long-term effects of synthetic chow diet on the metabolic pattern of diabetic syndrome in a large group of sand rats. Few animals had a fulminating reaction with markedly decreased glucose tolerance, low plasma insulin levels and death within 3-4 weeks. But the most of sand rats developed obesity and elevated plasma insulin levels. From the third month, 40% of sand rats presented a diabetic syndrome with hyperinsulinemia, hyperglycemia, markedly decreased glucose tolerance and insulin resistance. Plasma lipids were increased; the lipid and glycogen accumulation in the liver was high. So this diabetic syndrome can be compared to maturity onset diabetes. If this synthetic chow diet lasted more than 6 months, the most of animals lost considerable weight with a strong lipid depletion of fat stores. Serum immunoreactive insulin levels fall and the blood glucose rose over 500 mg/100 ml with glycosuria and ketonuria . The elevated triglyceride content of plasma and the lipid deposits in the liver were exaggerated; glycogen had disappeared. Animals developed an overtly insulin- dependent diabetes, the latter phase of the disease. The sand rat appears to us as a potentially interesting model for investigation both maturity onset and ketotic-type diabetic syndrome.

The effect of high glucose concentration on the proliferation and the synthesis of lipids in endothelial cells in culture.

Influence of glucose concentration on growth and lipid synthesis was investigated in human endothelial cells in culture. The biosynthesis of lipids from acetate and glucose was present in endothelial cells, but a high glucose level in the culture medium failed to modify lipid synthesis. Neosynthesis in the lipidic fraction in the medium is higher when precursor is acetate compared to glucose.