Hepatic changes during short-term haemodialysis

Twenty five patients with end stage renal disease were studied to find out the biochemical and hepatic morphological changes during short term haemodialysis. Asymptomatic hepatomegaly was seen in 32% of cases, transaminase elevation in 28% and positive Australia antigen in 12% of cases. Histopathological changes were observed in all the 12 patients in whom liver biopsy was done. Ten patients (82%) exhibited multiple abnormalities. The commonest findings were fatty change (8 patients); hepatic congestion, focal necrosis, Kupffer cell hyperplasia (6 patients each); and portal triaditis (5 patients).

Changes in striatal cholinergic, gabaergic, dopaminergic and serotoninergic biochemical markers after kainic acid-induced thalamic lesions in the rat

Kinetic parameters of 3H-choline, 3H-GABA and 3H-dopamine (DA) uptakes in striatal homogenates containing nerve endings were determined 2 to 3 weeks after kainic acid injection into the ipsilateral "centre médian"-parafascicular complex area of the thalamus in the rat. Results showed a marked decrease in 3H-choline uptake concomitant with a selective decrease in Vmax. Data also showed a large decrease in 3H-GABA uptake resulting from a decreased affinity of uptake sites for their substrate. These data were associated with the previously described decrease in choline acetyltransferase and increase in glutamic acid decarboxylase apparent activity, respectively. An apparent marked increase in 3H-DA uptake was likewise measured, mainly related to an increase in Vmax. Determination of serotonin (5HT) and 5-hydroxyindole acetic acid (5HIAA) endogenous contents showed in the deafferented striatum a decrease in 5HT concentrations associated with an increase in 5HIAA levels. Taken together, all these changes in neurotransmitter markers suggest that, directly through the thalamostriatal pathway or indirectly, the thalamus can exert a complex influence on striatal cholinergic and GABAergic neuronal functions as well as on the activity of dopaminergic and serotoninergic striatal afferent fibers.

Development of cholinergic markers in the neuroblastoma, N1E-115

The neuroblastoma, N1E-115, was grown for 9 days after subcultivation. The development of acetylcholinestrase (AChE), choline acetyltransferase (CAT), QNB-binding, choline uptake, and acetylcholine release was measured on days 1, 3, 6, and 9. In parallel experiments the irreversible AChE inhibitor soman was added to neuroblastoma on day 1 and the development of the above parameters except for release, was followed. AChE activity in the normal cells was found to develop also after confluency, whereas CAT activity and QNB-binding followed the development of most of the cellular proteins, i.e., ceased to develop at confluency. Both choline uptake and acetylcholine release appeared independent of cellular development. In the soman-treated cells the development of AChE was inhibited for up to 6 days and thereafter developed with the same rate as in the normal cells. CAT and QNB-binding developed as in the normal cells, but at a significantly reduced level. The development of choline uptake was not significantly different in soman-treated and normal neuroblastoma. It is concluded that the development of the cholinergic marker QNB-binding is intimately associated with that of the "presynaptic" marker CAT, whereas the development of AChE seems to be unrelated to these cholinergic parameters. The choline transport and the acetylcholine release seem to be equally well expressed on all the days studied.

gamma-Aminobutyric acid function in the rat striatum is under the double influence of nigrostriatal dopaminergic and thalamostriatal inputs: two modes of regulation?

Glutamic acid decarboxylase (GAD), gamma-[3H]-aminobutyric acid [( 3H]GABA) high-affinity uptake into synaptosomes, and endogenous GABA content were measured in the rat striatum 2-3 weeks following 6-hydroxydopamine injection in the ipsilateral substantia nigra to destroy the nigrostriatal dopaminergic pathway and after kainic acid injection into the centromedial-parafascicular complex of the ipsilateral thalamus to lesion the thalamostriatal input. Both lesions resulted in apparent GAD increase concomitant with a decreased [3H]GABA uptake into striatal synaptosomes. GABA content was increased selectively following the dopaminergic lesion. Kinetic analysis of the uptake process for [3H]GABA showed selectively a decreased Vmax following the dopaminergic lesion; in animals with thalamic lesion, however, the change only concerned the Km, which showed a decreased affinity of the transport sites for [3H]GABA. Determination of Km and Vmax for GAD action on its substrate glutamic acid showed an increased affinity of GAD for glutamic acid in the case of the dopaminergic lesion without any change in Vmax, whereas the thalamic lesion resulted in GAD increase concomitant with a selective increase in Vmax. These data suggest that striatal GABA neurons are under the influence of nigrostriatal dopaminergic neurons which may reduce the GABA turnover, whereas the exact nature of the powerful control also revealed on these neurons following thalamic lesion remains to be determined. Both lesions induced adaptive neurochemical responses of striatal GABA neurons, possibly reflecting in the case of the dopaminergic deprivation an increased GABA turnover.

Isolation and culture of biliary epithelial cells from the biliary tract fraction of normal rats

A method has been developed for the isolation of a population of cells enriched in epithelial lining cells from the bile ducts of normal rats. The procedure utilized digestion by pronase of the white strands of biliary and connective tissue which remained after hepatocytes had been mechanically removed from collagenase-perfused liver. The resulting cell population was enriched in cells whose ultrastructure resembled that of the epithelial cells of intrahepatic bile ducts. Contamination with hepatocytes, hepatocyte nuclei and erythrocytes was less than 2%. The cells have been maintained in short-term culture. The major morphological change during the first 2 days of culture was proliferation of microvilli, but cell protein composition was unchanged when analysed by polyacrylamide gel electrophoresis. A rabbit antiserum against bovine hoof prekeratin was used to immunohistochemically stain the intermediate filaments of biliary epithelium and was shown to stain more than 90% of the cells in the isolated cell population.

Histochemical localization of acetylcholinesterase in the glycogen body (sinus rhomboidalis) of common brown dove, Streptopelia senegalensis and house sparrow, Passer domesticus

Acetylcholinesterase (AChE) activity was studied in the glycogen bodies of the spinal cords of 2 birds namely Streptopelia senegalensis and Passer domesticus. A possible functional significance of AChE in the light of relative enzymatic localization especially in Hoffmann-Kolliker nuclei (motor cell groups), substantia gelatinosa and other regions of gray matter of 2 avian glycogen bodies has been discussed.

Role of interaction energy in the specificity of transcription. I-The Watson Crick G-C base pair template

The purpose of this work is to show that the selectivity of the nucleotide bases in RNA transcription c an be inferred, in principle, from the DNA base pair - RNA base interaction. The catalytic role of enzymes in this process is, therefore, only to form the sugar - phosphate backbone. A systematic study for the evaluation of the interaction energy of the DNA base pair with the enterant RNA bases have been undertaken to elucidate the aforesaid mechanism. Electrostatic hard sphere approximation of Nash and Bradley 1 has been employed. Non bonded induced dipole and London dispersion forces are not taken into account. The present communication gives the results of computations of the interaction energy of the four RNA bases. The results have been discussed with reference to Stent's and Zubay's schemes of RNA transcription.

Role of interaction energy in the specificity of transcription. II-The Watson Crick A-U base pair template

In continuation with work regarding the evaluation of the energy of association of various RNA bases with various base pairs, the results of the computations of the electrostatic interaction energy of A-U base pair with four RNA bases viz. Adenine, Uracil, Guanine and Cytosine have been reported. Non bonded induced polarization and dispersion potentials are not taken into account. Electrostatic hard sphere model of Nash and Bradley has been employed. Computations have been performed to find out the minimum energy configuration out of the various possible complex configurations. Results have been discussed with reference to similar calculations with G-C base pair performed by the authors.