Molecular Beams (Fraser, R. G. J.)

Abstract

Nevertheless, it is safe to say that those who will not trouble to learn the general principles of the Beilstein arrangement lose time in the long run.The scheme is really not complicated, considering the great diversity of organic compounds, but it needs some explanation.There are at least three published guides to Beilstein's Handbuch but only one, Huntress' pamphlet, is in English. It can be read in an hour or less but will continue to be useful for reference.It is a very clear presentation, accompanied by helpful charts. It might well be supplemented by the larger System der organischenVerbindungen by Prager, Stern, and Ilberg. The new edition of Huntress contains nine additional pages, the chief enlargement being in the section on the heterocyclic volumes and in the practice problems for locating compounds.Now that the fourth edition of Beilstein and its first supplement are so near completion, some training in its use becomes almost essential to students of organic chemistry who expect to become chemists. Their best help, unless they read German fluently, will be Dr. Huntress' book.

Insulin, dexamethasone and their interactions in the control of glucose metabolism in adipose tissue from lactating and nonlactating sheep

“…As a result gluconeogenesis is increased in the liver, but in addition glucose utilization in vivo by the rest of the body (apart from the mammary gland) is decreased (Bergman & Hogue, 1967). Glucose oxidation (Smith & Walsh, 1984) and acylglycerol glycerol synthesis from glucose (Vernon et al, 1981) are decreased in adipose tissue from lactating sheep. The objective of the present study was to ascertain if changes in glucose metabolism in adipose tissue of lactating sheep are associated with changes in the response or sensitivity of the tissue to insulin and glucocorticoids.…”

“…The regulation of glucose metabolism in sheep adipose tissue is not fully resolved. Insulin stimulates, whereas glucocorticoids inhibit, glucose utilization (Vernon, 1979;Plested et al, 1987a), as in the rat adipose tissue, but the mechanisms may differ. The major site of action of glucocorticoids in rat adipose tissue appears to be glucose transport across the plasma membrane (see Fain, 1979), whereas in sheep adipose tissue the major site(s) of inhibition by glucocorticoids appear to be distal to glucose transport (Plested et al, 1987a).…”

“…The major site of action of glucocorticoids in rat adipose tissue appears to be glucose transport across the plasma membrane (see Fain, 1979), whereas in sheep adipose tissue the major site(s) of inhibition by glucocorticoids appear to be distal to glucose transport (Plested et al, 1987a). Also, unlike rat adipose tissue, insulin has little or no effect on adiposetissue metabolism in sheep during incubations of 2-3 h (see Vernon, 1980), but does stimulate both fatty acid synthesis and, glucose utilization when incubations are prolonged for 24 h or more (Vernon, 1979(Vernon, , 1982Plested et al, 1987a).…”

In vivo rates of fat synthesis and fluxes of free fatty acids in lactating goats

“…Table 4 also shows that in vitro rates of fat synthesis found in tissues from fasting or lactating ruminants were very low. In studies with adipose tissues from different stages of lactation (VERNON et al 1981;SMITH and WALSH 1984) it was found that rates of fat synthesis were lowest in tissues from animals in earliest stages of lactation.…”

The hormonal control of fat metabolism in animals

“…The limited studies which have been performed suggest that the properties of insulin receptors in adipose tissue of the pig (Etherton 8z Walker, 1982) and the sheep (Vernon et al 1981) and in ruminant hepatocytes (Gill 8z Hart, 1981) are not greatly different from those of analogous receptors in the rat and man. Compared with rats, adipocytes from ruminants and pigs appear to be less responsive to insulin in vitro in terms of the maximal response to the hormone, although the concentration of insulin producing a half maximal effect is in the physiological range of 50-100 p U / d (Vernon, 1980). Differences in responses between farm animals and rats may partly reflect technical difficulties in working with the relatively fragile adipocytes of domestic livestock, so that many studies have been carried out using tissue slices rather than isolated adipocytes.…”