Effects of quarter individual and conventional milking systems on teat condition.

An on-farm experiment was performed to investigate the effects of two milking systems on teat condition. An auto-tandem milking parlor made by GEA(®) with a conventional milking cluster (CON) and a single tube milking system called MultiLactor(®) (MULTI) from Siliconform GmbH were tested. For both milking system, in total 73 animals were milked over a period of seven months. To assess the effect of milking on teat condition, each teat was scored according to teat-condition evaluation systems. To evaluate teat condition, the teat color, ring formation at the teat base and formation of teat hyperkeratosis were assessed. The evaluation was conducted once a month after milking. The collected data were then statistically analyzed with generalized linear mixed models. The only differences found between the two milking systems occurred with respect to their effect on teat color. MULTI showed significantly better scores compared to CON. There were no significant differences between the milking systems with regard to teat-end hyperkeratosis and ring formation at the teat base.

Potentiation of forskolin-induced increase of cAMP by diamide and N-ethylmaleimide in rat pancreatic islets.

In isolated rat pancreatic islets, the effect of diamide and N-ethylmaleimide (NEM) on forskolin- as well as on glucagon-induced elevation of cAMP was studied. Forskolin and glucagon increased cAMP levels in batch-incubated islets. Diamide and NEM further augmented forskolin-induced increase of cAMP levels, whereas glucagon-stimulated elevation of cAMP was not affected. From our data it is likely that under the conditions of the present study, the thiols related to the Ns-protein and the catalytic unit are insensitive to oxidation and alkylation. The potentiation of forskolin-induced cAMP production in intact islet cells by diamide and NEM may be due to inactivation of the thiols related to the Ni-protein.

Effects of propylthiouracil and methylthiouracil on cyclic AMP and ion movements in rat pancreatic islets.

Propylthiouracil and methylthiouracil have been shown to potentiate glucose-induced insulin secretion from rat pancreatic islets: the effect of methylthiouracil being less pronounced than that of propylthiouracil. In this study the effects of these substances on cAMP levels, 86Rb+ efflux, 45Ca2+ net uptake, and 45Ca2+ efflux were tested in isolated rat islets in order to obtain information on their possible mechanism of action. Propylthiouracil and to a lesser extent methylthiouracil increased islet cyclic AMP in a concentration-related manner. Maximum increases at the highest concentrations tested were 261% and 190% respectively. In the presence of 3 mM glucose propylthiouracil and methylthiouracil led to a decrease in the 86Rb efflux rate. With 5.6 mM glucose, both thiourea derivatives produced an increase in the 86Rb+ efflux rate which was independent of the presence or absence of calcium in the medium. Propylthiouracil and methylthiouracil augmented the 45Ca2+ efflux rate in the presence as well as in the absence of external calcium at various glucose concentrations. Propylthiouracil did not change, and methylthiouracil only slightly augmented, 45Ca2+ net uptake into the isolated islets. It is suggested that the synergistic effect of propylthiouracil and methylthiouracil on glucose-induced insulin release is at least in part due to an increase in islet cAMP levels. Whether the two substances have additional direct effects on ionic fluxes which contribute to their insulinotropic action or whether the observed changes in ion movements are secondary to the elevation of cAMP levels remains to be unclear and needs further investigation.

Forskolin: from an ayurvedic remedy to a modern agent.

Ancient Hindu Ayurvedic texts described the use of extracts from COLEUS species. An isolated diterpene from COLEUS FORSKOHLII, called forskolin, was demonstrated to be a hypotensive agent with spasmolytic, cardiotonic and platelet aggregation inhibitory activity. It has been shown to be a powerful activator of the enzyme adenylate cyclase in various tissues. Forskolin is thought to act on the catalytic subunit and also on the coupling mechanism of guanine regulatory sites (Ns and Ni) with the catalytic subunit. It is now clear that forskolin elicits physiological responses which have been shown to be cAMP-dependent.

Contamination of surface-water bodies after reactor accidents by the erosion of atmospherically deposited radionuclides.

Reactor safety analyses usually do not consider the population risk which might result from the contamination of surface-water bodies after reactor accidents by the erosion of atmospherically deposited radionuclides. This paper is intended to provide perspective on the reasonableness of this omission. Data are presented which are suggestive of the rates at which atmospherically deposited radionuclides might erode into surface-water bodies. These rates are used in the calculation of potential health effects resulting from surface-water contamination due to such erosion. These health effects are compared with predicted health effects due to atmospheric and terrestrial pathways after reactor accidents. The presented results support the belief that the contamination of surface-water bodies after reactor accidents by the erosion of atmospherically deposited radionuclides is not a major contributor to the risk associated with such accidents.

Effect of forskolin on islet cyclic AMP, insulin secretion, blood glucose and intravenous glucose tolerance in rats.

The in vivo effect of forskolin on insulin release, blood glucose and intravenous glucose tolerance test has been studied in the rat. In addition in vitro experiments on the effect of forskolin on islet cAMP and insulin release have been performed for comparison purposes. In batch incubated islets forskolin increased cAMP levels concentration dependently, the EC50 being approximately 25 microM. The maximal effect occurred after 5 min. In the presence of 2.8 mM glucose 10 microM forskolin did not stimulate insulin release; however, it potentiated both phase of 11.1 mM glucose induced insulin secretion. I.v. administration of 1.5 mg/kg of forskolin increased blood glucose levels in rats, which was associated with significant elevation of serum insulin. During an i.v. glucose tolerance test forskolin potentiated the insulin releasing capacity of glucose but did not significantly affect blood glucose levels. It is conceivable that cAMP per se does not initiate but rather amplifies insulin release by glucose. Since the synergistic effect of forskolin and glucose on insulin release in vivo is not associated with increased elimination rate it is possible that forskolin exhibits additional effects which counteract the glucose lowering action of insulin.