Duplication of the Ace.1 locus in Culex pipiens mosquito from the Caribbean

In Culex pipiens mosquitoes, AChE1 encoded by the locus Ace.1 is the target of organophosphorous and carbamate insecticides. In several resistant strains hompzygous for Ace.1RR, insensitive AChE1 is exclusively found. An unusual situation occurs in two Caribbean resistant strains where each mosquito, at each generation, displays a mixture of sensitive and insensitive AChE1. These mosquitoes are not heterozygotes, Ace.1RS, as preimaginal mortalities cannot account for the lethality of both homozygous classes. This situation is best explained by the existence of two Ace.1 loci, coding, respectively, a sensitive and insensitive AChE1. Thus, we suggest that in the Caribbean a duplication of the Ace.1 locus occurred before the appearance of insecticide resistance at one of the two copies.(AU)

Change in serum cholinesterase activity in Jamaican diabetics

This study investigates the alteration of serum cholinersterase levels in diabetics and its possible relationship to blood glucose, insulin, triglyceride, and cholesterol levels. Fourteen phasic insulin-dependent diabetes mellitus patients were comapared with 10 insulin-dependent diabetes mellitus, 10 noninsulin-dependent diabetes mellitus, and 10 normal controls. Each group was matched for age, sex, body mass index and duration of diabetes. Mean age was 56.7 ñ 2.5 years; mean body mass index, 24.00 ñ 0.8 kg/mý; and mean duration of diabetes, 14.2 ñ 2.2 years. Serum acetylcholinesterase, insulin, triglyceride, and cholesterol levels as well as fasting blood sugar were all assayed using standard techniques. Results suggest an associated increase of serum acetlycholinesterase with triglyceride levels in diabetics and may point to a possible association between increased serum acetylcholinesterase and vascular complications in Jamaican diabetics. (AU)

Enzyme activity in paroxysmal nocturnal haemoglobinuria - like red cells

Activities of two membrane enzymes, actylcholinesterase (AChE) and adenosine triphosphatase (ATPase), were studied in a patient with paroxysmal nocturnal haemoglobinuria (PNH), and in PNH-like cells produced by treating normal red cells with 2-aminoethyl isothiouronium bromide. AChE activity was low in the patient with PNH, particularly in the youngest red cells, but ATPase activity of whole blood was normal. AChE activity was decreased in PNH-like red cells, but ATPase activity and the activities of cytoplasmic enzymes were unchanged. These findings indicate that only the superficial part, and not the whole, of the red cell membrane is affected by the PNH lesion (AU)