Inhibition of hepatic Na+, K+-adenosinetriphosphatase in taurolithocholate-induced cholestasis in the rat

Summary Na⁺, K⁺-adenosinetriphosphatase (Na⁺, K⁺-ATPase) activity was decreased in liver plasma membranes from rats in which cholestasis had been induced by i.v. administration of sodium taurolithocholate (5 moles/100 g b. wt). Incubation of liver plasma membranes with taurolithocholate (10–1300 M) caused significant and dose dependent reductions of Na⁺, K⁺-ATPase activity at taurolithocholate concentrations above 100 M. These findings lend support to the hypothesis that cholestasis induced by monohydroxy bile acids is at least partially the result of an inhibition of hepatic Na⁺, K⁺-ATPase activity.This work was supported by the Swiss National Science Foundation.The authors thank Mr H. Sägesser and Miss B. Schütz for technical assistance.     

Effect of cholestasis and biliary diversion on the absorption of Na octanoate in the rat

Summary The intestinal absorption and portal vein transport of Na octanoate by isolate jejunal segments perfused in iivo were unchanged in rats studied 48 h after bile duct ligation or fistula.This work was supported by grant No. MT 4433 from the Medical Research Council of Canada.     

Inhibition of hepatic Na +, K + -adenosinetriphosphatase in taurolithocholate-induced cholestasis in the rat.

Na +, K + -adenosinetriphosphatase (Na +, K + -ATPase) activity was decreased in liver plasma membranes from rats in which cholestasis had been induced by i.v. administration of sodium taurolithocholate (5 mumoles/100 g b. wt). Incubation of liver plasma membranes with taurolithocholate (10--1300 muM) caused significant and dose dependent reductions of Na +, K + -ATPase activity at taurolithocholate concentrations above 100 muM. These findings lend support to the hypothesis that cholestasis induced by monohydroxy bile acids is at least partially the result of an inhibition of hepatic Na +, K + -ATPase activity.     

Effect of cholestasis and biliary diversion on the absorption of Na octanoate in the rat.

The intestinal absorption and portal vein transport of Na octanoate by isolated jejunal segments perfused in vivo were unchanged in rats studied 48 h after bile duct ligation or fistula.     

Spontaneous morphine withdrawal from the rat spinal cord

A characteristic and reproducible sign of narcotic withdrawal is the naloxone induced increase in arterial pressure. In morphine-dependent rats allowed to undergo spontaneous withdrawal (6-24 h) and then transected at the spinal C-1 level, arterial pressure was maintained at a significantly higher level than either spinal-transected nondependent controls or morphine-dependent, spinal-transected rats pithed from C-1 to L-4. These findings indicate that the morphine-dependent spinal cord, independent of supraspinal influences, is able to exhibit an autonomic component of spontaneous withdrawal.     

Spontaneous morphine withdrawal from the rat spinal cord

Summary A characteristic and reproducible sign of narcotic withdrawal is the naloxone induced increase in arterial pressure. In morphine-dependent rats allowed to undergo spontaneous withdrawal (6–24 h) and then transected at the spinal C-1 level, arterial pressure was maintained at a significantly higher level than either spinal-transected nondependent controls or morphine-dependent, spinal-transected rats pithed from C-1 to L-4. These findings indicate that the morphine-dependent spinal cord, independent of supraspinal influences, is able to exhibit an autonomic component of spontaneous withdrawal.This study was supported by the Medical Research Service of the Veterans Administration. A preliminary report of aspects of this work appeared in Soc. Neurosci. Abs.10 (1984) 1113.     

Spontaneous phospholipase A activity of rat pancreatic homogenates]

Rat pancreas presents a spontaneous phospholipase A activity which appears before trypsin activation at optimal pH 6.5. The responsible enzyme is independent of pancreatic prophospholipase A, as can be seen through experiments done in the presence of trypsin inhibitors. On the other hand, this enzyme is distinct from excretory phospholipase which is more active and whose optimal pH is 8.8. Thermostability and insensibility of spontaneously active phospholipase A to DFP differentiate it from lipase, carboxyl-esterhydrolase and lysophospholipase, respectively.     

Age-dependent increase of thermal stability of in situ chromatin of rat liver and its reversal after hepatectomy

Summary An age-dependent increase of thermal stability of DNA in situ has been demonstrated in rat liver by means of microfluorimetry, which was reversed to a great extent in old regenerated liver.These authors are guests for collaboration at Ancona (Italy) till July, 1976. Their permanent address: Biological Research Institute of the Hungarian Academy of Sciences, Tihany, Hungary.     

Impaired jejunal transport of monosaccharides in experimental cholestasis

Résumé L'absorption du 3-o-methyl glucose par des segments jéjunaux perfusés in vitro et par des anneaux inversés est diminuée chez le rat étudié 48 h après ligature du canal biliaire et non modifiée par l'addition de Na taurocholate au perfusat intestinal.     

Spontaneous mortality and vascular lesions in 3 rat strains with different blood pressure levels]

We have observed a high and significant mortality in spontaneously hypertensive rats compared to normotensive and hypotensive controls, in the fifth generation. The hypertensive rats exhibited a high frequency of cerebral haemorrhage and periarteritis nodosa.     

On the time reversal invariance of classical electromagnetic theory

David Albert claims that classical electromagnetic theory is not time reversal invariant. He acknowledges that all physics books say that it is, but claims they are “simply wrong” because they rely on an incorrect account of how the time reversal operator acts on magnetic fields. On that account, electric fields are left intact by the operator, but magnetic fields are inverted. Albert sees no reason for the asymmetric treatment, and insists that neither field should be inverted. I argue, to the contrary, that the inversion of magnetic fields makes good sense and is, in fact, forced by elementary geometric considerations. I also suggest a way of thinking about the time reversal invariance of classical electromagnetic theory—one that makes use of the invariant four-dimensional formulation of the theory—that makes no reference to magnetic fields at all. It is my hope that it will be of interest in its own right, Albert aside. It has the advantage that it allows for arbitrary curvature in the background spacetime structure, and is therefore suitable for the framework of general relativity. The only assumption one needs is temporal orientability.     

Pregnancy following segmental isthmic reversal of the rabbit oviduct

Summary Microsurgical reversal of a segment of rabbit proximal tubal isthmus has been followed by normal pregnancy in the first two animals to undergo the procedure. Establishment of pregnancy despite radical modification of the oviduct furnishes the opportunity to gain new insights into the mechanisms controlling tubal ovum transport and emphasizes the evolving feasibility and importance of tuboplastic microsurgery both as a research tool and clinical procedure.This study was partly supported by an N.I.H. Institutional Research Grant.Supported by the Rockefeller Foundation.     

Spontaneous thyroiditis in laboratory rats

Zusammenfassung Spontane Schilddrüsenentzündung wurde in einer Gruppe von BUF Ratten beobachtet. Das histopathologische Bild der Schilddrüse wies grosse ähnlichkeit mit Hashimoto's Schilddrüsenentzündung sowie experimentell hervorgerufener allergischer Thyroiditis in Laboratoriumstieren auf.     

Light reversal of a morphine-induced analgesia susceptibility rhythm in mice

Zusammenfassung Durch Tag-Nacht-Umkehr konnte bei Mäusen eine entsprechende Phasenverschiebung beim Muster der Sensibilität für die schmerzstillende Wirkung des Morphins erzielt werden.