Ovariectomy-induced bone loss and the hematopoietic system

To investigate the relationship of the hematopoietic system to the loss of bone due to ovarian hormone deficiency, we examined the effects of ovariectomy and estrogen administration on the thymus, spleen and the bone marrow, and on the proliferation of marrow progenitors of osteoclasts. We also assessed the effects of daily administration of interleukin-1 receptor antagonist (IL-1ra) on bone loss due to ovarian hormone deficiency. Ovariectomy resulted in decreased cancellous bone volume, increased trabecular osteoblast and osteoclast numbers, and increased serum alkaline phosphatase levels that were prevented by 17 beta-estradiol treatment. Thymus weight, spleen weight, thymus and spleen lymphocytes, and bone marrow monocytes and lymphocytes also increased significantly following ovariectomy, and the increases were suppressed by 17 beta-estradiol. Ovariectomy, in addition, caused a 4-fold increase in the number of tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells formed in cultures of marrow cells and the increase was partially inhibited by 17 beta-estradiol. IL-1ra administration did not prevent the bone loss due to ovariectomy. Our findings indicate that ovariectomy-induced bone loss in the rat is accompanied by marked changes in the hematopoietic system, and that these changes are modulated by estrogen administration. In spite of the negative finding with IL-1ra, the nature of the involvement of the hematopoietic system in the pathogenesis of bone loss due to ovarian hormone deficiency merits continued exploration.     

Calculation of the overlap angle in slip energy recovery drivesusing a d,q/abc model

A closed-form expression for estimating the overlap angle in a slip energy recovery system is presented. The prediction of the overlap angle is important in the case of doubly-fed induction motor drives, because of its influence on speed and torque. A closed-form expression is derived using a hybrid model of the induction motor and a dynamic model of the rotor rectifier. The ripple content of the DC link current and the inverter input voltage are neglected. The results predicted by the closed-form expression are verified experimentally     

Nutritional quality of uncultivated cereal grains utilised as famine foods in western sudan as measured by chemical analysis

The chemical composition of the grain of a number of wild grasses used as food in times of famine in western Sudan are reported and compared with those of the local staple cereals. Species investigated were Cenchrus hiflorus (haskaneet). Dactyloctenium aegyptium (korecb). Echinochloa colona (difra) and Oryza punctata (ruz el wadi). The grain of all species except C biflorus had protein contents in the range 110-140 g kg^?1, broadly similar to those of the local staple cereals. The grain of C biflours possessed a particularly high protein content of 210 g kg^?1. The nutritional quality of the proteins as measured by their chemical scores ranged from 20 for C biflorus to 65 for O punctata compared with scores of 36 and 58 for the local sorghum var Kurgi and millet respectively. Lysine was the limiting amino acid in all cases. Whilst the composition of the protein of sorghum var Kurgi was typical of sorghum generally, that of var Karamaka was unusual in possessing lysine levels of 3.4 g (16 g N)¹, double that normally present in sorghum and raising the chemical score of the protein to 62. The ash content of the famine food cereals was high, attaining 113 g kg¹ in C biflorus. All grains were good sources of zinc and D aegyptium. O punctata and E colonum additionally contained comparatively high levels of iron. Remarkably for a cereal D aegyptium was also very rich in calcium, containing over 10 g kg¹, and possessed high concentrations of manganese. Carbohydrate content of the famine food grains varied from 617 g kg¹ for C biflorus to 748 g kg¹ for O punctata, values comparable to the local staple cereals. The proportion of starch in this fraction ranged from 650 g kg¹ in D aegyptium to 940 g kg¹ in O punctata. Seed oils of all species were predominantly unsaturated containing mainly oleic and linoleic acids.     

A SURVEY OF MICROBIOLOGICAL ASPECTS OF CIDER MAKING

Among the lactic microflora of ciders it was found that the species Leuconostoc oenos was predominant at the end of the alcoholic fermentation as well as at the end of the malo-lactic conversion. Among yeasts, the genera Saccharomyces was predominant at the end of fermentation. However, in the case of one juice characterised by a low initial level of bacteria, a high amount of phenolic compounds and a small quantity of total nitrogen, the whole lactic flora was no longer detected after a fortnight.     

Stearoyl-coenzyme a desaturase activity in the mammary gland and liver of lactating rats

Stearoyl-CoA desaturase activity in microsomes from lactating rat mammary gland is very low (0.05–0.15 nmol/min/mg of protein) regardless of lactating time. In such microsomes, reductase activities and content of cytochrome b₅ are several-fold lower than in normal rat liver microsomes. Preincubation of the mammary microsomes with purified terminal desaturase gives a 55-fold stimulation of stearoyl-CoA desaturase activity, whereas preincubation with cytochrome b₅ has no effect. However, preincubation of mammary microsomes with both cytochrome b₅ and terminal desaturase results in a 200-fold stimulation of overall desaturation. These observations suggest that negligible stearoyl-CoA desaturase activity in lactating rat mammary microsomes is due to a low cytochrome b₅ content and the absence of terminal enzyme. The hepatic stearoyl-CoA desaturase activity increases 9-fold during lactation. There is little or no change in the NADH-cytochrome c reductase activity or in the concentration of cytochrome b₅ during this period, but the activity of the terminal desaturase increases with the increase of overall desaturation. These results suggest that liver is one of the more important sources of oleic acid for milk triglycerides.