Magnetic fields produced by phase transition bubbles in the electroweak phase transition.
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Journal Article↗
Biomedical subjects
D Bödeker
Publications and source records attributed to D Bödeker.
Participation of NH4+ in total ammonia absorption across the rumen epithelium of sheep (Ovis aries).
1. Participation of NH4+ in total ammonia transport across sheep rumen wall was studied in vitro. 2. In Ussing-type chambers addition of NH4+ or K+ to the incubation solution on the mucosal side of the epithelium evoked positive short-circuit currents (ISC). 3. The K+ induced ISC but not the NH4+ induced ISC could be blocked by Ba2+ whereas both, K+ or NH4+ induced ISC were blocked by quinidine. 4. Transepithelial fluxes of ammonia were significantly reduced when quinidine was present in the incubation solution. 5. When the transepithelial potential difference was clamped to -25 mV (polarity on the serosal side) ammonia fluxes from the mucosal to the serosal side were significantly larger than fluxes of ammonia measured as a potential difference of +25 mV. 6. It is suggested that NH4+ takes part in ammonia transport across the rumen epithelium, most probably by using a K(+)-transport system.
Ammonia↗
Really computing nonperturbative real time correlation functions.
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Journal Article↗
Pathophysiological and functional aspects of the megacolon-syndrome of homozygous spotted rabbits.
The Megacolon-Syndrome is a hereditary disease of homozygous spotted rabbits (En En). Investigations have been performed on some special traits related to functional aspects of the gut in comparison to vital heterozygous spotted rabbits (En en). It was found that En En rabbits showed significantly reduced sodium absorption rates across the wall of the cecum. Consequently, the dry matter content of the ingesta was reduced at this location, whereas the content of the ashes was increased. These results indicate that a further important pathogenetic aspect of this hereditary disease is an undue liquification of ingesta in proximal parts of the large intestine. Severe clinical problems, however, resulted from obstipation. This is concluded to be a late complication due to and modified by different stressors of endogenic and exogenic origin. Thus, there are some indications that an early site of spot-gene related effects might be the small intestine. This segment of the bowel was shorter and had an increased dry matter proportion of its wall when compared with heterozygous spotted rabbits. But a decreased proportion of dry matter within the wall of the large intestine was found. The latter could be an effect of the hypothyreotic state of metabolism in En En rabbits.
Animals↗
Access to the abomasum of sheep via a rumen fistula for follow-up studies during trichostrongylid infections.
A technique is described for the examination of the abomasum of adult sheep via a rumen fistula. The size of the fistula allowed a manual exploration of the rumen which was necessary to achieve an access to the abomasum. In four adult sheep, two of them infected with Haemonchus contortus, fibreoptic endoscopy was used to investigate the abomasal mucosa macroscopically as well as histopathologically and ultrastructurally by means of mucosal biopsy specimen. The acidity of the abomasal contents was measured directly by introducing an electrode into the abomasum or indirectly in abomasal fluid which was obtained via a stomach catheter through the rumen fistula. The measured values in all four sheep ranged between pH2 and 4. The fibreoptic examination of the abomasum did not influence the plasma pepsinogen and gastrin levels. The possibility of combining histological, serological and coprological data in follow-up studies on the pathophysiology of trichostrongylid infections in the abomasum of individual sheep seems to be useful for the investigation of primary and secondary infections and may contribute to a reduction of the number of experimental animals in such studies.
Abomasum↗
Studies on the transport in vitro of lysine, histidine, arginine and ammonia across the mucosa of the equine colon.
Discs of stripped mucosa from the proximal ventral colon were prepared immediately after slaughter of 8 Shetland cross-breed ponies. The mucosae were fixed in incubation chambers and used in incubation experiments to study the transmucosal fluxes of the amino acids lysine, histidine and arginine (150 min) and of ammonia (90 min). When the amino acid concentrations in the mucosal solution were in the physiological range (2.8-3.0 mmol/l) no transport to the serosal side of the tissue was found. When the concentrations were raised 10-fold, less than 2% of the mucosal amino acid pool was recovered in the serosal solution. Ammonia was transported across the mucosa at significant rates although only 63% of the ammonia that disappeared from the mucosal solution was found in the serosal solution. The findings show that the equine proximal colon is virtually impermeable to luminal free amino acids whereas ammonia is transported at rates equal to, or higher than those observed with rumen mucosa from sheep.
Amino Acids, Essential↗
Elevated urinary excretion of orotic acid in sheep caused by intraruminal infusion of sodium propionate.
1. The effect of sodium propionate on urinary excretion of orotic acid was investigated. 2. Solutions containing sodium propionate or NaCl, 750 mM/day each, were continuously infused into the rumen for 10 days. 3. During NaCl infusion, an urinary orotic acid excretion of 290 +/- 80 micrograms/day was noted. The intraruminal infusion of sodium propionate raised the concentration of propionic acid in the rumen fluid from 14.0 +/- 0.9 to 26.9 +/- 1.9 mM. 4. During this experimental period the excretion of orotic acid via urine significantly increased to 492 +/- 30 micrograms/day. Parameters of nitrogen balance were not altered by propionate. 5. It is suggested that the site of propionate action in intact sheep is in the pyrimidine synthesis pathway.
Animals↗
Influence of short-chain fatty acids on ammonia absorption across the rumen wall in sheep.
The effects of short-chain fatty acids (SCFA) on ammonia net absorption from the sheep rumen in vivo and on ammonia transport across rumen wall mucosa in vitro were studied. Ammonia net absorption was directly, though in a non-linear manner, correlated with the SCFA concentration in the artificial rumen fluid. Almost 70% of total ammonia absorption was dependent upon the presence of SCFA when 12 mmol l-1 ammonia and 67.5 mmol l-1 SCFA were present. Lactic acid was ineffective. Incubation experiments showed that mucosal disappearance and serosal appearance of ammonia were reduced by 38% and 32%, respectively, when SCFA (63 mmol l-1) were replaced by lactic acid. The SCFA effect was independent of the type of SCFA used. In part of the experiments up to 54% of the ammonia taken up by the tissue was not recovered in the serosal incubation solution and must have been metabolized in the mucosa.
Absorption↗
Involvement of carbonic anhydrase in ammonia flux across rumen mucosa in vitro.
Carbonic anhydrase activity in mucosa of the sheep rumen wall was completely inhibited by acetazolamide and ethoxyzolamide. This inhibition significantly reduced ammonia flux across mucosal discs in vitro but was ineffective if short-chain fatty acids were present in the bathing solution. The findings are discussed in relation to the mechanism of ruminal ammonia absorption.
Acetazolamide↗
Failure of 1,25-(OH)2-vitamin D3 to affect calcium flux across sheep rumen wall mucosa in vitro.
Isolated pieces of mucosa from the sheep rumen wall mounted between half-chambers were used in conventional incubation studies (1 h, 39 degrees C) with buffer solutions resembling rumen fluid (= mucosal fluid) and extracellular fluid (= serosal fluid), respectively. The mucosal-to-serosal (ms) flux of calcium was studied by use of 45CaCl2 with and without 1,25-(OH)2-vitamin D3 in the serosal incubation fluid. Different concentrations of the vitamin had no effect on Ca ms-flux.
Animals↗
Ammonia absorption from the isolated reticulo-rumen of sheep.
In fistulated sheep (50-60 kg live weight) the absorption of ammonia from the reticulo-rumen in vivo was studied applying the technique of the temporarily isolated and washed reticulo-rumen. It was found that, at ammonia concentrations between 3 and 18 mM, ammonia efflux and ammonia net absorption were linearly related to the ammonia concentration in the artificial rumen fluid, whereas influx of ammonia nitrogen from endogenous sources remained almost constant. When the concentration of unionized NH3 was changed at the ratio 1:10:76 by varying the pH from 5.8 to 6.8 and 7.7, ammonia net absorption did not reflect the concentration ratio of unionized NH3, indicating either flux of NH4+ ions or titration of NH4+ to NH3 at the absorptive surface. In the experiments with buffer solutions without ammonium salts and extended over 2 h, ammonia concentrations in the artificial rumen fluid increased due to endogenous nitrogen influx and reached levels far beyond the expected plateau concentration of about 2 mM. Labelling of the N pool in the isolated organ by 15N showed that ammonia efflux had almost ceased in these experiments. It is argued that as yet unidentified changes have taken place in the artificial rumen fluid during the experiment, but there is some reason to believe that volatile fatty acid (VFA) absorption was affecting ammonia absorption.
Absorption↗