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S Risse

Publications and source records attributed to S Risse.

At least 19 recordsLinked to original sources
PubMed2001

Involvement of intracellular Ca2+ in the regulation of bovine leukemia virus expression.

The calcium ionophore A23187, which was used to increase the intracellular calcium concentration ([Ca2+]i), was analyzed for effects on bovine leukemia virus (BLV) expression in two BLV infected cell lines. To clarify the role of intracellular free calcium in this response, [Ca2+]i was measured during ionophore treatment with the fluorescent calcium indicator Fura-2. Elevation of intracellular calcium under these conditions caused an enhancement of BLV gp51 and p24 synthesis as well as an activation of the BLV long terminal repeat (LTR) in a dose-dependent manner. Furthermore, it was observed that elevated levels of intracellular calcium following A23187 stimulation lead to activation of NF-kappaB. Based on inhibitor studies, we hypothesize that the effect of A23187 on BLV expression appears to be mediated by PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1995

Increase of antigen production in BLV-infected cell lines via additional expression of tax.

The selection of animals infected with the bovine leukaemia virus (BLV) is performed by the immunological detection of antibodies against the virus, commonly using the antigen gp51. Furthermore, research is being carried out to develop protective vaccines against BLV that have gp51 as their main component. Taking both of these factors into account, it is clear that there will be an increasing requirement for the virus antigen gp51 for some time to come. The permanently BLV-infected foetal lamb kidney cell line FLK/BLV (and its sublines) has been proved to be the most useful culture for the mass production of the virus antigen. Stable cell lines producing higher quantities of BLV antigen have not been established, either by subcloning of the FLK/BLV or by infection of other permanent cells with BLV. Here, a report is made on efforts to increase the expression of gp51 in BLV-infected cells via the additional expression of homologous transactivating virus protein tax. Selectable tax expression vectors that integrate into the host cell genome were constructed using BL provirus DNA fragments. Highly productive FLK/BLV cells were transfected with these vectors. Following selection with G 418, gp51-producing cell lines were established and tested for their productivity for several months. Some tax-vector-containing cell lines have produced 1.5-2 times more gp51 than the highly productive parental control cell line FLK/BLV 44-1.

Animals↗
PubMed1986

Depression--medical utilization and somatization.

We screened 147 primary care patients for depression using depression rating scales and a psychiatric interview. In the one year after screening, the patients with depression visited and phoned their physicians more frequently and had more medical evaluations than the nondepressed control group. The patients with depression were more likely to have nonspecific or vague complaints and psychophysiologic or depressive symptoms than the control group; their family physicians during this same period were more likely to diagnose a psychophysiologic problem.

Depressive Disorder↗
PubMed1983

[Behavior of various parameters of lipid and energy metabolism. 6. Energy turnover in various lengths of time in rats fed a low- and high-fat diet].

Weanling Wistar rats were fed a high-fat diet (HFD) or a low-fat diet (LFD) over 3 and 5-6 weeks. In both comparable groups the absorption of energy was almost the same. In the HFD animals glucose-6-phosphate dehydrogenase (G-6-PDH, E.C. 1.1.1.49) showed its well-known restrictive behaviour in the liver and also in the fatty tissues. After 3 weeks on the respective diet, the body fat content of the LFD animals was lower than that of the HFD animals. After 6 weeks on the respective diet, the body fat contents were nearly the same in the animals of both groups. The energy turnover was greater after 3 weeks on the diet than after 6 weeks, the significantly highest values being found in animals fed over 3 weeks. After 5 weeks on the respective diet, all the energy turnover values were at a lower level, but this was the same in both animal groups. It may be concluded that the fatty-acid synthesis de novo indicated by the G-6-PDH activity does not depend upon the experimental time, and is determined only by the amount of dietary fat. In contrast to this, the establishment of the energy turnover during the experimental time is subject to relatively great changes which might be correlated with the regulation of total fat retention in the body.

Animals↗
PubMed1982

[Endogenous lipid pattern, organ distribution and effect of diet on a fatty acid binding protein fraction of rat liver cytosol].

The endogenous lipid pattern of a fatty acid binding protein (FABP; synonym: "Z"-protein) in the cytosolic fraction of rat liver involves besides "free" fatty acids also phospholipids and mono-, di- and triacylglycerols. The relation between "free" fatty acids and the sum of all other lipids is nearly 1. In consequence of this result a correction of the idea is necessary that the FABP specifically binds only fatty acids. With immunological techniques it has been shown that the FABP has no organ-specificity and no immunological relation to the lipoproteins of the serum. A high content of fat in the diet (25% fat) compared with a low fat content of the diet (1% fat) led to an increase of the concentration of FABP in the cytosols of different rat organs (liver, intestinal mucosa, fat tissue and heart). Therefore a physiological function in the intracellular translocation of the fatty acids in different rat organs was inferred.

Animals↗
PubMed1978

[Behavior of certain parameters of lipid and energy metabolism. 5. Effects of high-fat and low-fat diets on certain biochemical parameters in rat livers before and after change of diet].

Typical metabolic patterns are detectable in the livers of growing rats after feeding diets with high (25%) or low (2%) fat contents. In view of the elucidation of problems related to the regulation of the metabolic processes, it is of interest to know in what way these metabolic patterns change after short-time change from the one diet to the other and if there are hierarchies. Within 2 days after change of diet, the enzymes glucose-6-phosphate dehydrogenase, NAD-malate dehydrogenase, lactate dehydrogenase, citrate synthase and fatty acid synthase were affected, only the 3'.5'-c AMP-splitting phosphodieterase showed no change. The metabolites lactate and pyruvate also changed, inversely to lactate dehydrogenase activity, the lactate-pyruvate ratio remaining almost constant. Acetyl CoA also responded in a characteristic manner. The single parameters were differently affected by the kind of the change of diet (from high-fat to low-fat diet or inversely). For example, glucose-6-phosphate dehydrogenase responded very rapidly to the change from the high-fat to the low-fat diet, malate dehydrogenase behaved inversely, and citrate synthase responded to both changes. Consequently, the regulatory processes after change of diet start from different sides. It is thinkable that this behaviour is related to the different roles of the determined parameters in fat and energy metabolism.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1977

[Behavior of certain parameters of lipid and energy metabolism. IV. Regulation of lipid and energy metabolism in livers and race and mini pigs].

To characterize the lipid and the energy metabolism in the livers of genetically different types of pigs (land race pig and mini pig), the authors determined the activities of enzymes typical of and limiting these metabolic pathways. Furthermore, they measured the concentrations of typical metabolites and ascertained parameters that are of importance in energy metabolism. The concentrations of acetyl CoA and free fatty acids in the livers of mini pigs were significantly greater than those in the livers of land race pigs, whereas the cholesterol, glycerol, triglyceride and acetoacetate concentrations were reduced. The activities of glucose-6-phosphate dehydrogenase (E.C.1.1.1.49.), citrate synthase (E.C.4.1.3.7.) and ATP citrate lyase (E.C.4.1.3.8.) were lower in the livers of mini pigs than in the livers of land race pigs, whereas the activity of fatty acid synthase was higher. The concentrations of cyclic 3',5'-adenosine monophosphate (AMP) and adenosine diphosphate (ADP) were lower in the livers of mini pigs than in those of land race pigs. In land race pigs, the metabolic process seems, therefore, to be determined in favour of the degradation of free fatty acids and of the generation of energy. In mini pigs, lipogenesis in the liver appears to be the decisive metabolic pathway. The possibility of a higher coordinating control mechanism of the lipid and the energy metabolism is discussed.

ATP Citrate (pro-S)-Lyase↗
PubMed1976

[Behavior of some parameters of lipid and energy metabolism. 1. Behavior of the stationary concentrations of acetyl CoA, acetoacetate and adenosine phosphates in liver, as well as oxygen consumption and P/O ratios in liver homogenates of growing rats on diets differing in fat content].

Young rats were maintained on diets differing in fat content. The determination of certain parameters of the lipid and the energy metabolism in the liver showed that a high-fat diet resulted in a reduction of the stationary level of acetyl CoA, an increase in the concentration of acetoacetate and a reduction of the adenosine triphosphate content and the so-called energy charge. In case of intact respiratory chain phosphorylation, the oxygen consumption of the respective liver homogenates was simultaneously increased. The results obtained with a high-fat diet are indicative of the attainment of a metabolic state which seems to be typical of metabolic regulations in growing rats subjected to anabolic lipometabolism.

Acetoacetates↗
PubMed1976

[Behavior of some parameters of lipid and energy metabolism. 2. Activity of citrate synthase, ATP citrate lyase, fatty acid synthase, and glucose-6-phosphate dehydrogenase in liver of growing rats on diets differing in fat content].

In continuation of previous investigations, the authors studied the behaviour of the activities of certain enzymes (citrate synthase, adenosine triphosphate citrate lyase, fatty acid synthase and glucose-6-phosphate dehydrogenase) in the livers of growing rats on diets differing in fat content. A high-fat diet resulted in a reduction of the activities of fatty acid synthase, glucose-6-phosphate dehydrogenase and adenosine triphosphate citrate lyase, whereas the activity of citrate synthase increased, which is interpreted in the sense of an acceleration of the introduction of acetyl residues into the citrate cycle for the purpose of oxidative final degradation, and as a removal of acetyl CoA for the purpose of fatty acid synthesis.

ATP Citrate (pro-S)-Lyase↗
PubMed1976

[Behavior of certain parameters of lipid and energy metabolism. 3. Relationships between cyclic 3',5'-adenosine monophosphate and acetyl coenzyme A in liver of growing rats deduced from model experiments with diets differeing in fat content].

Schemes of the lipid and the pyruvate metabolism serve to show that a great part of the enzymes which intervence in the metabolic pathways and are associated with the formation and the consumption of acetyl coenzyme A may be regulated by cyclic 3',5'-adenosine monophosphate (cAMP) in the sense of activation or inhibition. The cAMP increase in the liver, which has been demonstrated in the present study for a diet containing 25% of fat, opens the metabolic pathway to the formation of acetyl coenzyme A by means of fatty acid degradation and simultaneous inhibition of lipogenesis. The deficiency of insulin (which has been evidenced in previous paper) characterizes, together with the facts mentioned, a state like diabetes or the fasting state. Acetyl coenzyme A is mainly used for energy supply. The close negative correlation between cAMP and acetyl coenzyme A (which is shown in the present paper) permits to conclude that the extent and trend of the increase and decrease in the liver is subjected to intensive hormonal control in which cAMP in involved.

Acetyl Coenzyme A↗
PubMed1975

[Effect of changing fat and protein levels on various fundamental characteristics of lipid and protein metabolism in the blood serum and on the body composition of growing rats].

A total of 263 young rats received 6 different diets containing varying levels of lipids and proteins. After a feeding period of not less than 3 weeks the animals were killed in a fasted state or after feeding and the blood serum was investigated for total lipids, free fatty acids, cholesterol, urea, creatinine and insulin. The bodies of the animals were analyzed for crude fat und crude protein. The body proteins seemed to be hardly influenced whereas considerable variations were noticed in the values for body fat, although these were not found to be clearly related to the intake of dietary fat. Values for the content of total lipids, free fatty acids and cholesterol in blood serum were shown to be clearly dependent on the amount of fat ingested. In addition, it was observed that these processes were partly influenced by dietary proteins. The values for urea, creatinine and insulin were only slightly affected by dietary fat, but were markedly changed by dietary proteins. Differences in total lipids and cholesterol as discussed above were blurred or disappeared altogether when the animals were analyzed after food intake; on the other hand, it was shown, that dietary proteins had a statistically well-established effect on the values for urea and a marked influence on insulin values.

Animal Nutritional Physiological Phenomena↗