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PubMed1982

Effect of cholesterol on the reconstituted D-glucose transport system of human erythrocyte membranes.

Human erythrocyte membranes were solubilized by cholate. Reconstitution into phospholipid liposomes containing different amounts of cholesterol was performed by chromatographic removal of cholate. Glucose transport was determined as the differential uptake of radioactive D- and L-glucose. The reconstituted glucose transport activity decreased with increasing concentration of cholesterol up to about 20 mole percent. Further increase in cholesterol concentration resulted in an increase in the glucose transport activity.

Blood Glucose↗
PubMed1978

Reconstitution of carbamylcholine-dependent sodium ion flux and desensitization of the acetylcholine receptor from Torpedo californica.

Membranes rich in acetylcholine receptor were isolated from Torpedo californica by a modification of the procedure of Sobel et al. (Sobel, A., Weber, M., and Changeux, J.-P. (1977) Eur. J. Biochem. 80, 215-224). The receptor was extracted with 2% potassium cholate in the presence of 2.5% soybean phospholipids. After reconstitution by the cholate dialysis procedure, the vesicles exhibited a rapid, carbamylcholine-dependent uptake of 22Na+, which was inhibited by alpha-bungarotoxin and several other known inhibitors. At concentrations above 5 x 10(-5) M carbamylcholine, the fast phase of Na+ influx lasted less than 10 sec. At 5 x 10(-6)M, it lasted 30 sec but was only about 50% of the maximal total uptake observed at optimal agonist concentration. The phenomenon of desensitization was exhibited by the reconstituted vesicles. When 2 x 10(-4)M carbamylcholine was added, 15 sec before 22Na+, the rapid Na+ influx phase was no longer observed.

Acetylcholine↗
PubMed1982

Differences of the in vitro reactivity of lymphocytes from normal and persistently lymphocytotic cows to enzootic bovine leukosis tumour membrane extracts as detected with the macrophage-electrophoretic mobility test.

The response of peripheral blood lymphocytes from normal and persistently lymphocytotic cows to cell membranes and sodium cholate-extracted membrane proteins from normal and tumourous lymph nodes was tested with the macrophage-electrophoretic-mobility test with guinea pig peritoneal macrophages as indicator cells. Lymphocytes from 13 cows with persistent lymphocytosis (PL) showed a positive reaction with cholate extracts from tumour cell membranes. On the other hand, there was a negative reaction with corresponding extracts from normal lymph nodes for 11 animals. 4 of 10 hematologically normal cows also showed a positive reaction against tumour cell membrane extracts. One of these, however, thereafter developed antibodies against BLV glycoprotein gp 51. Using tumour cell membrane preparations as antigen, the 4 cows with PL tested also exhibited a positive reaction, whereas none of 3 hematologically normal cows showed any reactivity. As efforts to detect the main antigenic proteins of BLV (gp 51, p 24) in detergent extracts of tumour cell membranes proved unsuccessful, these findings are thought to provide evidence for the existence of a common non-viral antigen on cell membranes of bovine leukosis tumour cells.

Animals↗
PubMed1980

[Demonstration and characterization of tumor-associated antigenic components from cell membranes of a UV-induced murine sarcoma using the MEM technic].

Purification of tumour-associated antigenic material from the ascites sarcoma cells was attempted by extraction with 3 M KCl and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The antigenic activity was assayed in the macrophage-electrophoretic-mobility (MEM) test. Extraction of whole tumour cells with 3 M KCl results in preparations with low antigenic activity which on SDS-PAGE show a very heterogenous composition of more than 20 protein bands. On comparison of the antigenic activity of different subcellular fractions obtained by differential centrifugation of the homogenate, the antigenic activity could be alloted to the cell membrane fraction. With this cell membrane fraction, three extraction media -- 3 M KCl, 2% Triton X-100, and 5% sodium cholate -- were tested for their ability to selectively extract the antigenic membrane proteins. The Triton X-100 treatment solubilized the greatest amount of membrane protein. Both Triton X-100 and sodium cholate, however, produced very heterogeneous protein extracts. In contrast, 3 M KCl selectively extracted three membrane components: a glycoprotein of high molecular weight and two low-molecular-weight carbohydrate-free proteins. Removal of the KCl in the presence of Triton X-100 precipitates the carbohydrate-free proteins, while the glycoprotein remains in solution. Testing the components of the KCl-extracts in the MEM-test after isolation by preparative SDS-PAGE revealed antigenic activity only with the glycoprotein component.

Animals↗
PubMed1995

The F0 complex of the Escherichia coli ATP synthase. Investigation by electron spectroscopic imaging and immunoelectron microscopy.

Cholate-solubilized F0 complexes of the ATP synthase (F0F1) from Escherichia coli were studied by application of conventional transmission electron microscopy and electron spectroscopic imaging (ESI) of negatively stained samples. Using the ESI mode, the structural organization of the F0 complex (diameter of 7.5 +/- 0.5 nm) could be observed in more detail and defined projections could be distinguished. Projection A appears as a deltoid-like structure with bilateral symmetry. Projection B has an overall trapezoidal shape with some similarity in shape to the letter W. Applying the ESI mode to the ac complex dissolved in cholate-containing buffer, an elongated structure consisting of two intensity maxima could be observed. Simulations with models of the F0 and the ac complex revealed that the projections observed can be obtained by tilting and rotating a model in which subunit a and the two copies of subunit b are located outside the subunit c oligomer. This view of structural organization was supported by results obtained with F0 complexes decorated with monoclonal antibodies against subunits a, b or c.

Antibodies, Monoclonal↗
PubMed1979

Adrenocortical cytochrome P-450 side chain cleavage. Preparation of membrane-bound side chain cleavage system from purified components.

Soluble cytochrome P-450 from bovine adrenocortical mitochrondria, capable of side chain cleavage, can be incorporated into membranes prepared by dispersion of phospholipids in aqueous buffer when cholate is added to the membrane suspension. In addition, the complete protein side chain cleavae system (i.e. including the ancillary proteins adrenodoxin and adrenodoxin reductase and the substrate cholesterol) can be incorporated into such membranes so that on addition of TPNH, pregnenolone is formed. These components remain in the membrane through gel filtration (which removes almost all the cholate) and sedimentation through sucrose density gradients which separate vesicles without protein and soluble enzyme from the membrane-bound P-450 remains associated with the membrane during and following lysis of vesicles. The vesicles which do not leak [14C]glucose were seen on electron microscopy to show a mean diameter of 350 to 450 A. A number of phospholipids are capable of accomodating P-450 in this manner: mitochondrial lipid extracts, synthetic dipalmitoyl phosphatidylcholine, synthetic dipalmitoyl phosphatidylserine, and egg lecithin, separately or in various combinations. Cholesterol is not necessary for incorporation of the side chain cleavage system. Membrane-bound P-450 shows a Vmax of 28.1 nmol of pregnenolone/min/mg of protein, more than 10 times that of soluble P-450. The spectral properties of the soluble P-450 are altered to become predominantly low spin in the membrane and the enzyme is more stable at 4 degrees C than is soluble p-450.

Adrenal Cortex↗
PubMed1994

Sodium retention does not occur at a critical threshold of liver function in alcoholic cirrhosis.

Sodium retention is triggered in rats with experimental liver injury at a critical threshold of liver function. We compared liver function and sodium retention in serially studied patients with alcoholic cirrhosis to determine whether a similar threshold exists in human beings. Antipyrine, caffeine, and cholic acid clearance were measured in 35 men with alcoholic liver disease. Nineteen patients were evaluated on two or more occasions; between studies, 28 remained in sodium balance (group NN), six spontaneously developed sodium retention and ascites formation (group NY), and seven spontaneously lost ascites (group YN). A threshold between patients with and without sodium retention did not exist for any of the clearance measurements. Indeed, values overlapped widely between the two groups. Antipyrine and cholate clearance were significantly reduced in patients with sodium retention, but caffeine clearance was similar in the two groups. Antipyrine and caffeine clearance declined significantly between the first and second study in group NY; cholate clearance did not change. No significant differences were observed between studies in group YN. In several patients of this group, liver function worsened as ascites spontaneously resolved. Impaired liver function commonly but not invariably accompanies sodium retention in patients with cirrhosis. A threshold at which sodium retention occurs or resolves does not exist.

Antipyrine↗
PubMed1993

Direct energization of bile acid transport into plant vacuoles.

Bile acids were shown to be transported into barley mesophyll vacuoles. Uptake of the cholate conjugates taurocholate and glycocholate is strictly ATP-dependent. Uptake of taurocholate is a saturable process (Km = 40 microM) and is inhibited by vanadate but not by bafilomycin, a specific inhibitor of the vacuolar H(+)-ATPase. Together with the observation that the non-hydrolyzable ATP analog AMPPNP (5'-adenylyl beta,gamma-imidodiphosphate) does not stimulate, but rather inhibits, the ATP-dependent uptake of taurocholate, and that a 3-fold accumulation of the bile acid is observed in the presence of bafilomycin, these results suggest that taurocholate is transported into the vacuole by a primary active process as is the case for its canalicular secretion in rat liver (Nishida, T., Gatmaitan, Z., Che, M., and Arias, I. M. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 6590-6594). Taurocholate uptake is inhibited by other bile acids and is slightly stimulated by glutathione S-conjugates. The different responses of the glutathione S-conjugate (Martinoia, E., Grill, E., Tommasini, R., Kreuz, K., and Amrhein, N. (1993) Nature 364, 247-249) and the taurocholate transporters, respectively, to substrates, oligomycin, GTP, and UTP suggest the presence of at least two ATPases specifically involved in the transport of conjugates across the tonoplast. As cholate and its conjugates have so far not been reported to occur in plants, the physiological function of the novel transport ATPase described here is presently unknown.

Adenosine Triphosphatases↗
PubMed1993

Hydrodynamic properties and immunological identification of the sodium- and chloride-coupled glycine transporter.

We have recently reported the purification of the native sodium- and chloride-coupled glycine transporter from pig brain stem (López-Corcuera, B. Vázquez, J., and Aragón, C. (1991) J. Biol. Chem. 266, 24809-24814). This preparation is essentially homogeneous and contains a unique 100-kDa polypeptide based on electrophoretic migration under denaturing conditions. In this paper we report the hydrodynamic characterization of the native transporter, solubilized in two different detergents, as well as the immunological identification of the protein. On the basis of results obtained from size-exclusion chromatography, we calculated the Stokes radii of transporter 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS) and transporter-cholate complexes to be 5.5 and 6.0 nm, respectively. In addition, from H2O/D2O sucrose density gradient sedimentation analysis, we calculated the molecular weight of protein-detergent complexes to be 115,000 and 160,000 in CHAPS and cholate, respectively, and the molecular weight of the protein moiety as 86,000. Finally, polyclonal antibodies raised against the 100-kDa polypeptide were found to immunoprecipitate specifically glycine transport activity. Taken together, the results reported herein corroborate the identity of the 100-kDa band as the sodium- and chloride-coupled glycine transporter and also suggest that in its native state the transporter is a monomeric protein.

Amino Acid Transport Systems, Neutral↗
PubMed1993

Taurine conjugate of 3 alpha,6 beta,7 beta-trihydroxy-5 beta,22-cholen-24-oic acid (tauro-delta 22-beta-muricholate): the major bile acid in the serum of female rats treated with alpha-naphthylisothiocyanate and its secretion by liver slices.

The taurine conjugate of 3 alpha,6 beta,7 beta-trihydroxy-5 beta,22-cholen-24-oic acid (tauro-delta 22-beta-muricholate) has been identified in the serum of female rats treated with alpha-naphthylisothiocyanate. Using a high performance liquid chromatographic/enzymatic method for measurement of bile acids, tauro-delta 22-beta-muricholate was the predominant bile acid in the serum of female Fischer 344 rats treated for 3 days with alpha-naphthylisothiocyanate. Other significant changes in concentrations of serum bile acids included increases in tauro-alpha-muricholate, tauro-beta-muricholate, taurocholate, taurochenodeoxycholate, and several unknown bile acids. The formation of tauro-delta 22-beta-muricholate was examined in vitro using liver slices from control rats and rats treated with alpha-naphthylisothiocyanate. Slices were incubated for 7 h in William's E medium containing no bile acids or 25 mumol/l of one of the following: beta-muricholate, tauro-beta-muricholate, or cholate. Tauro-delta 22-beta-muricholate was secreted by slices from control and treated rats and the rate was increased significantly by the addition of beta-muricholate (2.9-5.6-fold) but not tauro-beta-muricholate or cholate to the medium. Tauro-delta-beta-muricholate was formed by liver slices from endogenous precursors and from exogenous beta-muricholate. Pretreatment of rats with alpha-naphthylisothiocyanate did not alter total secretion rates but those of some important individual bile acids were affected. Because of the increased secretion of tauro-delta-beta-muricholate by liver slices with the addition of beta-muricholate to the medium, the liver may be the primary site of formation for this unsaturated bile acid.

1-Naphthylisothiocyanate↗
PubMed1993

Bile acid synthesis from newly synthesized vs. preformed cholesterol precursor pools in the rat.

The present study defines the origin of cholesterol subserving bile acid synthesis in male rats with an extracorporal bile duct by labeling newly formed cholesterol with tritiated water. Within 6 hr after interruption of the enterohepatic circulation, the bile acid pool was depleted. At this early time point the proportion from de novo cholesterol was 8% and 12% for biliary cholesterol and cholate, but 18% and 19% for muricholate and chenodeoxycholate, respectively. This proportion gradually rose to 40%, 34%, 51% and 51%, respectively, at 15 to 30 hr. At 78 hr after bile diversion, 64% of cholate was labeled, compared with 84% to 88% of the other biliary lipids and 71% of plasma cholesterol. Total and labeled bile acid secretion exhibited the same diurnal rhythm. To allow differentiation between direct hepatocytic de novo synthesis of bile acids from acetate and recycling of labeled plasma cholesterol, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (pravastatin) was infused from 54 to 78 hr. It suppressed total synthesis of primary bile acids by 60% to 80% but decreased the tritium label of bile acids only from a range of 74% to 92% (54 hr) to a range of 54% to 63% (78 hr), which was in the range of plasma cholesterol (58%). We conclude that bile acids and biliary cholesterol are synthesized mostly from preformed (i.e., plasma) cholesterol, both immediately after depletion of the pool in enterohepatic circulation and after derepression. Moreover, the hepatic cholesterol pools subserving the synthesis of different bile acids and biliary cholesterol secretion are not identical.

Acetates↗
PubMed1995

Hepatic transport of bile acid and effect of conjugation.

Biliary transport of bile salts was investigated by measuring: 1) biliary transport maxima values (Tm) for different conjugated bile salts; and 2) biliary excretion of unconjugated bile salts relative to their conjugates under the continuous i.v. infusion of various unconjugated bile salts. The order of Tm values found in the rat of both sexes was tauro (and glyco) ursodeoxycholate (TUDC, GUDC), tauro alpha- and beta-muricholate (T alpha-MC, T beta-MC) > taurocholate(TC) > taurochenodeoxycholate (TCDC), while in female hamsters it was TC > TCDC > TUDC. The differences in the Tm order between rats and hamsters cast doubt on the currently proposed view that the apparent Tm values of bile salts are primarily determined by their physical-chemical properties (detergent property in particular). The biliary excretion of unconjugated bile salts was most efficient with ursocholate (UC) and alpha-MC followed by beta-MC, with UDC (and probably 7 ketolithocholate) being the least efficient for excretion. Thus, while for some bile salts such as cholate and UC, the amidation is not a prerequisite to their efficient excretion, for other bile salts such as UDC, the amidation is an excellent mechanism for facilitating the biliary excretion. In an attempt to explain the above order for the efficacy of the biliary excretion of unconjugated bile salts on the basis of their physical-chemical properties, we must remember that unlike rats, the biliary excretion of dehydrocholate and cholate in dogs is more limited than their respective taurine conjugates.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMedDate not supplied

Physical stability of teniposide in bile salt-egg phosphatidylcholine mixed micelles and liposomes.

Teniposide-containing bile salt-egg PC mixed micelles and their liposomes formed from dilution were investigated and compared for (i) their teniposide contents as a function of bile salt species, drug dose, the egg PC/BS molar ratio, total lipid concentration, ionic strength and storage states (freeze-thawed and freeze-dried state, and the presence of light and oxygen) and (ii) their mean particle size, stored under different conditions. The physical stability of teniposide in micelles and their liposomes increased with increasing hydrophobicity of bile salt the order being deoxycholate > cholate > conjugated cholate at all temperatures (10 degrees C, 23 degrees C, and 45 degrees C) studied. Teniposide-micelles were more stable at lower egg PC/BS molar ratios, while teniposide-liposomes were more stable at higher ratios. Teniposide stability slightly increased at higher total lipid concentration, indicating that bile salt-egg PC mixed micellar systems were in dynamic states. The presence of neither light nor oxygen significantly affected the stability of teniposide over the time and temperature range studied. However, the presence of salt in micellar and liposomal solutions greatly reduced teniposide loss by precipitation. Freezing or freeze-drying of teniposide-micelles induced neither micellar aggregation nor drug leakage. The stabilization may be due to the presence of detergent-like bile salts in the system.

Antineoplastic Agents, Phytogenic↗
PubMed1977

[Experimental cholestasis by dibucaine and harmaline: effects on bile flow and hepatic transport of bile acids, ethacrynic acid and ouabain (author's transl)].

For further confirmation of the hypothesis that bile-salts independent bile flow depends on transepithelial Na+ fluxes, the effect of dibucaine (0.5 to 1.6 mM) and of harmaline (1.7 to 4.0 mM) on bile formation was studied in the isolated rat liver. Both compounds, which are known to inhibit passive Na+ entry into tissues other than liver, inhibit bile secretion in a dose-dependent fashion. Measurements of oxygen consumption and examination of liver tissue by electronmicroscopy exclude unspecific damage to liver cells as the cause for secretory failure. Cholestasis induced by dibucaine and harmaline is reversible upon wash-out of the drugs from the perfusion system. Simultaneously added choleretics, such as taurocholate, cholate, ethacrynic acid or ouabain, fail to elicit a secretory response. Since harmaline is an inhibitor of Na+-dependent transport processes, its effect and that of dibucaine on Na+-linked uptake of these choleretics by the isolated liver was determined. Harmaline and dibucaine reduce taurocholate transfer to the extent of the Na+-independent fraction only, but completely inhibit active entry of cholate, ethacrynic acid and ouabain. It is concluded that drug-membrane interactions primarily on the sinusoidal surface but possibly also at the canalicular pole of the hepatocytes are responsible for the impairment of basal and stimulated bile secretion.

Alkaloids↗
PubMed1996

Evidence of two catalytically active carnitine medium/long chain acyltransferases in rat liver peroxisomes.

Peroxisomal matrix proteins were extracted from the highly purified peroxisomes with sodium pyrophosphate, and the membranes were sedimented by high speed centrifugation. Biochemical marker enzyme analyses revealed a quantitative release of a number of well-known peroxisomal matrix proteins from the purified peroxisomes. In contrast, carnitine medium/long chain acyltransferase activity, assayed with decanoyl-CoA and palmitoyl-CoA as substrates, was equally distributed in the membrane and the matrix fractions. The matrix and the membrane enzyme activities were differentially affected by a number of detergents. The enzyme in the membrane fraction showed higher malonyl-CoA sensitivity compared to the enzyme in the matrix fraction. The enzyme(s) from the purified peroxisomes or the peroxisomal membranes was quantitatively solubilized by sodium cholate, and the cholate-solubilized enzyme retained malonyl-CoA sensitivity. The membrane enzyme was separated from the matrix enzyme by hydroxylapatite column chromatography. The separation of the membrane enzyme or the matrix enzyme by hydroxylapatite column chromatography resulted in loss of malonyl-CoA sensitivity. The partially purified membrane and the matrix enzymes showed broad substrate specificity, and the highest enzyme activities for both were observed with decanoyl-CoA. In contrast to the matrix enzyme, the membrane enzyme was strongly inhibited by high concentrations (> or = 50 microM) of acyl-CoAs (> 10 carbons in length). The matrix enzyme showed a 2.5-fold lower Km for carnitine compared to the membrane enzyme. The catalytic properties of the partially purified matrix enzyme appear to be similar to the well-characterized peroxisomal carnitine octanoyltransferase, though we find highest activity with decanoyl-CoA rather than octanoyl-CoA as a substrate. The data presented clearly indicate that the membrane and the matrix enzyme activities are due to different proteins.

Acyl Coenzyme A↗
PubMed1977

Purification and reconstitution of the adipocyte plasma membrane D-glucose transport system.

Rat adipocyte plasma membranes have previously been shown to retain stereospecific transport activity for D-glucose following extraction of extrinsic proteins with dimethylmaleic anhydride (Shanahan, M. F., and Czech, M. P. (1977) J. Biol. Chem. 252, 6554-6561). When these extracted plasma membranes were incubated in 2% sodium cholate and centrifuged, the resultant supernatant contained only one major glycoprotein fraction of 94,000 daltons, as determined by dodecyl sulfate-polyacrylamide gel electrophoresis. This protein fraction was combined with cholate-dispersed, exogenous phospholipids. The detergent was removed by gel filtration and vesicles composed of phospholipid and membrane protein were formed which exhibited preferential, time-dependent uptake of D- versus L-glucose when measured by a rapid filtration method. In addition, D-glucose uptake was inhibited by cytochalasin B, phlorizin, phloretin, and dipyridamole. These results suggest the direct involvement of the 94,000-dalton glycoprotein fraction in fat cell hexose transport.

Adipose Tissue↗
PubMed1976

Side chain hydroxylations in biosynthesis of cholic acid. 25- and 26-Hydroxylation of 5beta-cholestane-3alpha, 7alpha, 12alpha-triol by reconstituted systems from rat liver microsomes.

25- and 26-Hydroxylation of 5beta-cholestane-3alpha, 7alpha, 12alpha-triol was studied with reconstituted systems from rat liver microsomes consisting of partially purified cytochrome P -450, NADPH-cytochrome P -450 reductase, a phospholipid, and an NADPH -generating system. Cytochrome P -450 was prepared either by sodium cholate treatment and ammonium sulfate fractionation or by subtilisin and sodium deoxycholate treatment followed by DEAE-cellulose chromatography. No side chain hydroxylation was observed when cytochrome P-450 was omitted. With ammonium sulfate-fractionated cytochrome P-450 25- and 26-hydroxylation was stimulated 5- to 8-fold by addition of NADPH-cytochrome P-450 reductase. With subtilisin-treated cytochrome P-450 an almost absolute requirement for NADPH-cytochrome P-450 reductase was observed. Omission of lipid did not reduce the rate of hydroxylation. Centrifugation of the cytochrome P-450 preparation at 100,000 X g for 1 hour just before incubation increased markedly lipid dependency. A significant difference between 25- and 26-hydroxylation was observed with respect to substrate saturation. The stimulatory effect of phenobarbital treatment on 25-hydroxylation and the inhibitory effect of this treatment on 26-hydroxylation were associated with the cytochrome P-450 fraction. The use of increasing amounts of sodium cholate in the solubilization of cytochrome P -450 resulted in a gradual decrease of 25-hydroxylase activity and a gradual increase of 26-hydroxylase activity. 25- and 26-Hydroxylase activities were separated partially by chromatography of subtilisintreated cytochrome P-450 fraction on DEAE-cellulose. The question whether different species of cytochrome P-450 are involved in 25- and 26-hydroxylation is discussed.

Animals↗
PubMed1976

Kinetics of [14C]cholic acid in fulminant hepatic failure: a prognostic test.

The kinetics of intravenously injected [14C]cholic acid have been investigated in 14 patients with fulminant hepatic failure, 24 to 36 hr after the development of grade IV encephalopathy. Radioactivity was measured in plasma samples and in the individual plasma bile acid fractions after separation by thin layer chromatography. Plasma disappearance curves of the free [14C]cholic acid were calculated by an iterative nonlinear least squares fitting procedure using a computer. The disappearance of total plasma radioactivity was similar in all patients and greatly prolonged compared with healthy subjects. However, the plasma disappearance of free [14C]cholic acid was significantly faster in the 8 patients who recovered consciousness than in the 6 who did not. Plasma disappearance of free [14C]cholic acid correlated highly significantly with the proportion of conjugated [14C]cholate in plasma. All patients in whom more than 70% of plasma radioactivity was in the conjugated fraction 3 hr after injection survived and left hospital, whereas all of those in whom less than 55% was conjugated died. Measuring the percentage conjugation of [14C]cholate 3 hr after injection may therefore be a useful test of residual liver function in hepatic failure, as a guide to prognosis and in evaluating new forms of treatment.

Adolescent↗