[Do cognitive sciences open therapeutic paths in schizophrenia?].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
M Senn
Publications and source records attributed to M Senn.
Evidence for different nutrient partitioning in Boran (Bos indicus) and Boran x Holstein cows when re-allocated from low to high or from high to low feeding level.
This study tested the hypothesis that purebred Boran (Bos indicus) cows and crossbreds of Boran and Holstein respond differently to long-term changes of feeding level in nutrient partitioning to milk and body fat stores. A total of 27 cows of these two genotypes were subjected either to a low or a high feeding level from their first oestrus as heifers until birth of their third calf. Half of the cows of each genotype were then switched to the other feeding level during the third reproduction cycle. If at all, Boran cows responded to a change in the feeding level almost exclusively by a corresponding change in body weight but not milk yield. Crossbred cows kept continuously on the low feeding level had a lower milk yield than those continuously fed the high level, but lost similar amounts of body weight. In crossbred cows, changing the feeding level from high to low was accompanied by a mobilization of body reserves, whereas a change from low to high level resulted mostly in an increase in milk yield. Certain other genotype differences in metabolic response were obvious from differences in body composition and from the metabolic profile either reflected in blood (particularly insulin-like growth factor I) or in adipose tissue (lipoprotein lipase). Reproductive performance differed between genotypes, with shorter lactations associated with earlier occurrences of the first oestrus in the Boran cows. Generally, feeding history appeared to have at least as much influence on energy partitioning as the actual feeding level. In conclusion, purebred Boran cows seem to react to long-term food fluctuations mainly by mobilizing and restoring body fat reserves, whereas cows crossbred with Holstein tend to spend extra energy preferentially for milk production.
Adipose Tissue↗
Effect of water restriction on feeding and metabolism in dairy cows.
We investigated how lactating cows are able to cope with a sustained water restriction. In experiment 1, body weight and meal patterns were recorded with ad libitum access to water (baseline) and during 8 days of 25 and 50% restriction of drinking water relative to ad libitum intake. In experiment 2, indirect calorimetry was combined with nitrogen and energy balance and plasma hormone and metabolite measurements to assess the effects of 50% water restriction on digestion and metabolism. In experiment 1, food intake and body weight declined during the first 3 days of water restriction depending on the restriction level and stabilized thereafter at a lower level. The daily food intake reduction with 50% water restriction was entirely due to a reduction of meal size. The size of the first meal on every day was markedly (>50%) reduced with 25 and 50% water restriction. In experiment 2, urea concentrations in milk and blood as well as plasma sodium and hematocrit were increased by 50% water restriction. Energy balance was not affected by 50% water restriction, but nitrogen balance became negative, because, relative to intake, nitrogen excretion via urine and milk was higher. The lower energy intake during 50% water restriction was compensated by a lower milk production, a higher digestibility of organic matter and energy, and, apparently, a more efficient energy use. Through these changes and a preserved water balance, the cows reached a new equilibrium at a lower water turnover level, which enabled them to cope with a sustained drinking water restriction of 50%.
Animals↗
Lactational and metabolic effects in cows of lysine and methionine added to a ration deficient according to the I.N.R.A. method.
The effects of adding lysine and/or methionine to a ration of calculated deficiency in these amino acids of 10% and 20%, respectively, were studied in 24 Brown Swiss cows. The mixed rations (27% grass silage, 19% maize silage, 5% hay and 49% concentrate on DM basis) contained 14.5% CP on average. Lysine supply was selectively elevated by adding fish meal in exchange for other concentrate ingredients. Methionine was supplied in a rumen-protected form. Milk protein content was elevated whereas fat amount decreased by adding both amino acids. Lactose content increased without additional lysine from fish meal. Live weight, milk yield, milk fat content and protein amount remained unaffected by any variation of amino acids supply. Also nutrient digestibility and nitrogen balance were not changed by the treatments. Blood plasma concentrations confirmed the assumed variation in metabolic lysine and, less clear, methionine supply. Effects on plasma concentrations of other amino acids were relatively small. Most plasma hormones and enzymes, and metabolites in plasma, urine and milk did not respond to the variation in amino acid supply. Lysine addition via fish meal increased aspartate amino transferase and decreased urinary allantoin concentration. Additional methionine elevated plasma ornithine. Overall lysine and methionine appear to have been only marginally deficient in the unsupplemented ration fed for 3 weeks despite the deficiency of 10% to 20% as calculated by the I.N.R.A. method.
Amino Acids↗
Effect of a prolonged low-dose lipopolysaccharide infusion on feed intake and metabolism in heifers.
Prolonged infusions of bacterial lipopolysaccharides (LPS) are known to model gram-negative bacterial infections, but the basic mechanisms of the LPS effects on feed intake and metabolism and their potential interdependence are largely unknown. The aim of the present study was to distinguish and to better characterize the feeding suppressive and metabolic effects of LPS. Six heifers were infused intravenously for 100 min with either 1) LPS (2 microg/kg BW) with free access to feed, 2) saline with free access to feed, or 3) saline with feeding restricted to the amount of feed consumed after LPS infusion. Feed intake, body temperature, plasma concentrations of various metabolites and hormones, and the respiratory quotient and heat production were measured. The LPS reduced feed intake and induced pronounced changes in metabolic energy turnover and fat and carbohydrate metabolism that were largely independent of the concomitant feed intake reduction. Some of the metabolic changes were biphasic; the first phase resembled a stress response with increases in plasma glucose and cortisol, and the second phase reflected a beginning energy deficit with low plasma glucose and enhanced lipolysis. The coincidence of a short-term surge of plasma insulin with marked transient decreases in plasma FFA, glycerol, and beta-hydroxybutyrate as well as with the transition from hyper- to hypoglycemia indicates that insulin plays a role in some of the metabolic responses to LPS. The failure of LPS to clearly increase energy expenditure despite the increase in body temperature suggests that anaerobic mechanisms of heat production and, perhaps, a reduced peripheral blood flow contributed to the fever. Many of the initial metabolic responses occurred before and, therefore, independent of, an increase in circulating tumor necrosis factor-alpha.
Adipose Tissue↗
Lesion of the area postrema/nucleus of the solitary tract (AP/NTS) attenuates the anorectic effects of amylin and calcitonin gene-related peptide (CGRP) in rats.
The area postrema/nucleus of the solitary tract (AP/NTS) region plays an important role in the control of food intake since it receives peripheral satiety signals via splanchnic and vagal afferents. Due to the lack of the blood brain barrier in this region, blood borne signals can directly be monitored in the AP/NTS. Furthermore, receptors for anorectic peptides such as amylin or calcitonin gene-related peptide (CGRP) have been found in the AP/NTS. It was therefore the aim of the present study to investigate the role of the AP/NTS region in mediating the anorectic effects of these peptides. Thermal ablation of the AP/NTS resulted in a significant reduction of the anorectic effects of IP injected amylin (5 microg/kg) and CGRP (5 microg/kg) in food deprived rats. The anorectic actions of CCK and BBS were also reduced by the AP/NTS lesion which agrees with previous studies. We conclude that the AP/NTS region is an important brain site for mediating the anorectic effects of amylin and CGRP. It remains to be clarified whether this effect is due to amylin and CGRP action on receptors within the AP/NTS region or peripheral receptors on afferent nerves projecting to the AP/NTS.
Afferent Pathways↗
Vaccine genotype and route of administration affect pseudorabies field virus latency load after challenge.
The influence of vaccine genotype and route of administration on the efficacy of pseudorabies virus (PRV) vaccines against virulent PRV challenge was evaluated in a controlled experiment using five genotypically distinct modified live vaccines (MLVs) for PRV. Several of these MLVs share deletions in specific genes, however, each has its deletion in a different locus within that gene. Pigs were vaccinated with each vaccine, either via the intramuscular or intranasal route, and subsequently challenged with a highly virulent PRV field strain. During a 2-week period following challenge with virulent PRV, each of the vaccine strains used in this study was evaluated for its effectiveness in the reduction of clinical signs, prevention of growth retardation and virulent virus shedding. One month after challenge, tissues were collected and analyzed for virulent PRV latency load by a recently developed method for the electrochemiluminescent quantitation of latent herpesvirus DNA in animal tissues after PCR amplification. It was determined that all vaccination protocols provided protection against clinical signs resulting from field virus challenge and reduced both field virus shedding and latency load after field virus challenge. Our results indicated that vaccine efficacy was significantly influenced by the modified live vaccine strain and route of administration. Compared to unvaccinated pigs, vaccination reduced field virus latency load in trigeminal ganglia, but significant differences were found between vaccines and routes of administration. We conclude that vaccine genotype plays a role in the effectiveness of PRV MLVs.
Administration, Intranasal↗
Effect of water deprivation on eating patterns of lactating cows fed grass and corn pellets ad lib.
The present study investigated the effect of 48 h of water deprivation on eating behavior of 12 lactating cows fed grass and corn pellets ad lib. Water deprivation reduced grass and corn pellet intake significantly, with corn pellet intake decreasing earlier than grass intake. The reduction of feed intake was entirely due to a reduction of meal size for both grass and corn-pellet meals. The size of the first meal of the water deprivation period was already reduced by about 30%. Grass-meal frequency increased, whereas corn-pellet meal frequency decreased during water deprivation. Water deprivation also decreased live weight and milk yield by about 12 and 30%, respectively. All parameters returned to baseline values with rehydration. With ad lib access to feed and water, 77% of drafts occurred in relation to meals, but the number of meals clearly exceeded the number of drafts. The results demonstrate that water deprivation rapidly leads to premature meal termination. This is in line with the assumption that an enhanced prandial increase in ruminal fluid osmotality contributes to dehydration-induced hypophagia. Yet, further studies are necessary to prove this assumption and to better understand the complex relationships between eating and drinking in ruminants.
Animals↗
Kinetics of primary bile acids in patients after orthotopic liver transplantation.
Administration of cyclosporin A (CsA) may induce cholestasis, and this effect has been attributed to impaired hepatocellular uptake, transport, secretion and intestinal absorption of bile acids. Disturbances of the enterohepatic circulation may affect metabolism of bile acids. To test whether liver transplantation and treatment with CsA alters pool sizes or synthesis and turnover rates, we determined kinetics of primary bile acids in patients after orthotopic liver transplantation on CsA. Two male and four female patients were studied 6-20 months after transplantation. They had no overt signs of cholestasis, graft dysfunction or rejection. Kinetics of cholic acid (CA) and chenodeoxycholic acid (CDCA) were simultaneously determined after oral administration of [24-13C]-CA and [24-13C]-CDCA on the basis of isotope dilution in a single pool of bile acids. Ten healthy volunteers served as controls. After orthotopic liver transplantation, pool sizes, fractional turnover rates and synthesis rates of both primary bile acids, CA and CDCA were not significantly different from control subjects. In spite of the known interference of CsA with the enterohepatic circulation of bile acids, in the majority of patients after orthotopic liver transplantation without cholestasis, graft dysfunction of rejection, treatment with CsA does not disturb kinetics of primary bile acids.
Adult↗
ACTH, cortisol and glucose responses after administration of vasopressin in cattle and sheep.
The present study compared the effects of vasopressin on plasma concentrations of corticotropin, cortisol and glucose in cattle and sheep. After intravenous injection of 1, 0.1 and 0.01 microgram vasopressin per kg body weight, the plasma vasopressin concentration increased proportionally to the injected dose, and this increase was similar in cattle and sheep. Doses of 1 and 0.1 microgram per kg body weight of vasopressin triggered significant responses of corticotropin, cortisol and glucose in cattle and sheep. The corticotropin response to both doses was significantly greater in sheep, whereas the glucose response was greater in cattle. The cortisol response did not differ between species. The lowest dose of vasopressin (0.01 microgram per kg body weight) still induced a significant cortisol response without a substantial effect on plasma corticotropin, suggesting that a direct action of vasopressin on the adrenals may contribute to the observed cortisol response. The results demonstrate that vasopressin increases plasma levels of corticotropin, cortisol and glucose in cattle, as it does in sheep, but the intensities of the corticotropin and glucose responses to vasopressin differ between cattle and sheep. The reasons for these differences remain to be clarified.
Adrenocorticotropic Hormone↗
Limited importance of a learned aversion in the hypophagic effect of interleukin-1 beta.
This study addressed the possible role of a learned aversion in the hypophagic effect of interleukin-1 beta (IL-1 beta) in the rat. Two repetitive intraperitoneal injections of IL-1 beta (2 micrograms/kg body weight = b.wt.) progressively reduced intake of a novel-tasting saccharin diet (SD) presented immediately after injection. When SD and the familiar diet were offered some days after an injection, SD selection was in some but not all trials reduced by IL-1 beta pretreatment. When SD was offered alone several days after an injection, SD intake was not affected by the initial pairing of SD presentation with IL-1 beta injection. In further experiments, the novelty of a flavor added to the diet fed immediately after injection proved to be crucial for the aversive effect of IL-1 beta, and enhanced its hypophagic effect. Finally, lesion of the area postrema and the adjacent nucleus of the solitary tract failed to affect the hypophagia induced by IL-1 beta (1 microgram/kg b.wt.). The results indicate that, under certain conditions, IL-1 beta can induce an aversion to the taste and flavor of the food consumed after injection. This aversive effect of IL-1 beta appears to be rather weak and is presumably not involved in the hypophagic effect of IL-1 beta under normal feeding conditions. It may however enhance IL-1 beta's hypophagic effect under certain conditions, for instance after repeated injections.
Animals↗
Feeding patterns of lactating cows of three different breeds fed hay, corn silage, and grass silage.
Feeding behavior of 35 lactating cows of three different breeds (Holstein-Friesian = HF, Simmental = SI, and Jersey = JER) was compared in the present study. The cows were kept in a loose housing system and fed hay, corn silage (CS) and grass silage (GS) ad lib. Within 7 consecutive days, 2918 meals were recorded and analyzed: 2503 meals were eaten during the light phase (0430-2200), and 57% of these diurnal meals consisted of only one feedstuff (43% hay, 9% CS, 5% GS). During the dark phase, only 23% of the 415 meals consisted of hay alone, but 16% of CS and 21% of GS alone. This circadian distribution showed no breed differences, yet meal patterns did: HF and SI cows ate 11 meals per day, and JER cows ate more than 13 meals/day. Meal size was 9.8MJ, 7.9MJ, and 5.8MJ for HF, SI, and JER cows, respectively. HF cows had the highest 24 h energy intake and JER cows the lowest, but the latter spent the most time feeding. During the light phase all three breeds obtained the most energy from hay, followed by CS and GS. In contrast, during the dark phase most energy was derived from GS, and hay contributed the least. A significant premeal correlation was observed for cows of all breeds, in particular during the time with the highest feeding activity (0800-1300). During the dark phase no premeal correlation could be detected; instead a significant postmeal correlation appeared, in particular in HF and SI cows.(ABSTRACT TRUNCATED AT 250 WORDS)
Animal Feed↗
A model for the evolution of networks of genes.
An organism persists through the activity of structural genes, which is co-ordinated by clusters of coupled regulatory genes. During evolution, changes of coupling within a cluster can increase the reliability with which its structural genes perform a task. To study the evolution of coupling, we have simulated and analyzed a stochastic model for a simple problem. The assumptions of the model are these: A network of regulatory genes co-ordinates the synthesis of four structural proteins, which associate in distinct heterodimers that form a heterotetramer. Mutation in cis-regulatory regions produces transitions among 64 types of network. In a population, each network reproduces in proportion to its fitness, which depends on its probability (reliability) of synthesizing the tetramer. Fitness-dependent attrition keeps the size of the population constant. Regulatory genes occur in a sequence of levels; each level is associated with a different family of transcription factors. The following results emerge: Because different messengers within a family can give networks with the same connectivity, the 64 types of networks cluster into eight equivalence classes. During evolution with a low mutation rate, high-fitness classes can be approached through various paths on a fitness landscape. With a higher mutation rate, networks remain more uniformly distributed among the 64 types, and lower-fitness networks remain preponderant. An initially homogeneous population becomes more heterogeneous through mutation, but selection according to fitness later reduces its diversity. During this process the dispersion of the population over the possible networks increases, then decreases as the population approaches a unique steady state.
Animals↗
[Seroprevalence of hepatitis C virus in hemophiliacs in Switzerland].
The sera of patients with hemophilia and von Willebrand factor deficiency, collected during clinical trials with virus-inactivated coagulation factor preparations, were retrospectively screened for the presence of antibodies against hepatitis C virus (HCV). Using the anti-HCV c100-3 assay, 10 out of 35 study patients had no HCV antibodies when entering the studies. The samples originally negative for anti-HCV were retested with a second-generation assay: all negative samples except two were positive on retesting. We conclude that the HCV seroprevalence in Swiss hemophiliacs must be of the order of > 90%. These results confirm that the first-generation assay for HCV antibodies is not sensitive enough; to obtain more accurate information on the seroprevalence of hemophiliacs, second-generation tests should be used.
Hemophilia A↗
Eating patterns of lactating dairy cows of three different breeds fed grass ad lib.
Eating behavior of lactating cows of three breeds (Holstein-Friesian = HF, Simmental = SI, and Jersey = JER) was compared in the present study. The cows were kept in a loose housing system and fed grass and hay ad lib along with concentrates. Within 11 days, 1396, 1504, and 1682 grass meals were recorded and analyzed for HF, SI, and JER cows, respectively. In cows of all three breeds, 89% of the grass meals (= 94% of the total grass intake) occurred during the light phase (0400-2200) and peaks of grass intake with large meals were always observed shortly after refilling the troughs. A similar diurnal distribution was evident for concentrate intake, but was less pronounced (28% eaten during the dark phase), and peaks of concentrate intake occurred also in the evening and after midnight. Hay intake was negligible and was not considered for meal pattern analysis. JER cows ate generally less than HF or SI cows, but spent more time eating. Grass meal frequency was higher, but grass meal size and mean eating rate within grass meals was smaller for JER cows than for HF and SI cows. Significant correlations between the size of grass meals and the duration of either the interval preceding or following that same meal were observed only for some animals (in particular JER and SI cows) during the main eating period in the morning (0800-1300), but barely in the afternoon (1300-1700). Thus, the short-term physiological control of meal-taking in dairy cows kept under normal farming conditions seems to be markedly influenced by external factors.(ABSTRACT TRUNCATED AT 250 WORDS)
Animal Feed↗
Does a learned taste aversion contribute to the anorectic effect of bacterial lipopolysaccharide?
The present study addressed the possible role of a conditioned taste aversion in the anorectic effect of bacterial lipopolysaccharide (LPS) in the rat. Pairing an intraperitoneal (IP) injection of LPS (100 micrograms/kg b.wt.) with the subsequent presentation of a familiar diet (FD) or of a novel-tasting saccharin diet (SD) for several hours did not affect FD or SD intake when the same diet was offered several days later after 12 h of food deprivation. However, food intake during the second presentation of SD was reduced when food was not withheld prior to the test. In a similarly designed experiment, the antipyretic and antiinflammatory drug indomethacin (5 mg/kg b.wt., IP) attenuated the anorectic effect of LPS during the initial pairing, but did not affect the inhibition of SD intake in LPS-pretreated rats during the second feeding test. The antiemetic trimethobenzamide (5 mg/kg b.wt., IP) failed to influence the anorectic effect of LPS. Lesion of the area postrema (AP) and the adjacent nucleus of the solitary tract (NST) was found to enhance the anorectic effect of LPS, but the development of tolerance to this effect remained unchanged in AP/NST-lesioned animals. In spite of the ability of LPS to induce a taste aversion that inhibits feeding under certain conditions (novel-tasting diet, no food deprivation prior to the feeding test), the findings indicate that a learned taste aversion is not the only contributor to the anorectic effect of LPS.
Animals↗
Effect of ursodeoxycholic acid on the kinetics of cholic acid and chenodeoxycholic acid in patients with primary sclerosing cholangitis.
Treatment of patients with cholestatic liver diseases with ursodeoxycholic acid has been shown to have beneficial effects that may be related to a shift in the balance between hydrophilic and hydrophobic bile acids in favor of hydrophilic bile acids. During treatment of patients with primary sclerosing cholangitis with ursodeoxycholic acid, plasma concentrations of some endogenous bile acids decrease. To test whether the changes in plasma bile acids are due to decreases of their pool sizes or synthesis rates, we determined bile acid kinetics of cholic and chenodeoxycholic acid in six patients with primary sclerosing cholangitis, of whom four also had ulcerative colitis. All patients were studied before and 3 mo after the start of ursodeoxycholic acid treatment. Six healthy subjects served as controls. In patients with primary sclerosing cholangitis, pool sizes of cholic and chenodeoxycholic acid were considerably smaller than those in healthy controls; after ursodeoxycholic acid treatment they were unchanged. Fractional turnover and synthesis of cholic acid increased significantly after ursodeoxycholic acid administration. Fractional turnover of chenodeoxycholic acid also increased significantly, whereas synthesis of this bile acid was unchanged. Our data indicate that in patients with primary sclerosing cholangitis, pool sizes of bile acids are reduced. The decrease of levels of endogenous bile acids in plasma under ursodeoxycholic acid treatment despite unchanged bile acid pool sizes indicates redistribution of the bile acids into the enterohepatic circulation, probably because of improved hepatic clearance after ursodeoxycholic acid treatment.
Adult↗
Biliary excretion of iron in healthy man and in patients with alcoholic cirrhosis of the liver.
We measured the biliary excretion of iron in 11 patients with alcoholic cirrhosis of the liver and in 10 healthy controls using an intestinal perfusion technique. In the patients with cirrhosis increased amounts of iron in liver tissue were present. The concentrations of iron in the bile samples were determined by atomic absorption spectrometry. The biliary excretion of iron in the healthy controls was 0.32 +/- 0.09 mumol/h and in the patients with cirrhosis it was 0.45 +/- 0.14 mumol/h. The biliary excretion of iron in the patients with cirrhosis was not reduced, indicating that other mechanisms than a reduced biliary excretion of iron must be responsible for the accumulation of iron in liver tissue in alcoholic cirrhosis.
Adult↗