In rats on a diet with a sodium content of 300 mmol/kg, lithium is reabsorbed exclusively in the proximal tubules, and lithium clearance (C_Li) equals the proximal tubular fluid output (V_prox). In rats on a sodium-poor diet (5 mmol/kg), lithium is also reabsorbed in the distal nephron and C_Li is therefore lower than V_prox. The present paper examines the reduction of C_Li in response to a low sodium diet in Brattleboro rats with hereditary diabetes insipidus maintained on different dietary potassium contents. C_Li was reduced by about 60 μl/min./100 g body weight in response to a low sodium diet. The absolute reduction in C_Li caused by low sodium diet was unaffected by an increase of C_Li provoked by administration of potassium with the diet, and it was unaffected by variations of C_Li which occurred spontaneously within each group. C_Li was accordingly reduced by a constant absolute value rather than by a constant percentage. The reduction of C_Li (60 μl/min./100 g body weight) was equal to C_Li in the group given a potassium-poor diet with a normal sodium content. In the low-sodium and low-potassium group C_Li was reduced to almost zero. Using C_Li as a measure of V_prox in the rats on a 300 mmol/kg sodium diet it is concluded that the absolute reduction of C_Li in response to a sodium-poor diet is 1) unaffected by increase of V_prox produced by administration of potassium with the food, 2) unaffected by spontaneous variations of V_prox, and 3) equal to V_prox in rats given a potassium-poor diet.

The goal of this study was to evaluate dietary patterns among South Floridian Latino women with Type 2 diabetes against American Diabetes Association (ADA) dietary recommendations, and ascertain the issues that interfere with adoption of diet prescriptions. Free-living, adult Latino females (N=128), diagnosed with type 2 diabetes and living in Miami-Dade, South Florida participated in the study. Diet recalls were assessed for caloric and macronutrient composition, and patients were asked about reinforcing and detracting influences on their compliance with dietary recommendations, understanding of diet prescriptions including medication and sick-day guidelines. Estimated daily caloric intake ranged from 571 to 4405 Kcal and the mean (±SD)was 1837.26 (±673.93). Macronutrient intake patterns compared with ADA guidelines were 90.9% of recommended percent caloric contribution from carbohydrate, 120% for protein, and 107% for fat. Only 46.9% of subjects consumed a combined carbohydrate and monounsaturated fat intake of 60–70% of calories per ADA guidelines. Most participants reported eating a typically South Floridian Latino diet; that the most significant change made to their diets was not to its quality, but rather quantity; and that it was inconvenient to cook differently for ‘the rest of the family’ so their own diet composition remained unaltered.

Compensation in mean relative growth rate of M. persicae occurred when aphids normally kept on susceptible brussels sprout plants were starved for only 2 h daily or kept on ‘resistant’ plants (given low nitrogen:high potassium fertilization) for 48 h. More adverse conditions, e.g. 4 or 8 h daily starvation, 48 h on leaf discs or 60 h on 20% sucrose, resulted in a low aphid growth rate being maintained on transfer to susceptible plants. The low overall growth rate could not be explained in terms of a weight loss by the aphid at any stage and is assumed to be a behavioural phenomenon. It is concluded that it is unwise, in the study of aphid—plant relationships, to rely on pre-conditioning aphids in poor conditions with the hope that this might magnify differences in subsequent aphid response.