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Non-operative treatment of retained bile duct calculi in patients with an indwelling T tube.

The results of combined instrumental and chemical treatment of retained bile duct calculi in 18 patients with an indwelling T tube are reported. The instrumental extraction of stones was carried out through the T tube channel using a modified Dormia apparatus. The chemical method involved continuous infusion through the T tube of heparin in saline alternating with sodium cholate. The treatment was successful in 16 of 18 patients with from 1 to 14 residual stones. The instrumental extraction of stones is recommended as the treatment of choice 5--6 weeks after choledochotomy in patients with residual stones and an indwelling T tube. Subsequent chemical treatment is recommended if remnants of stones are left in the bile duct after instrumental treatment.

Adult↗

Characterization of Leishmania donovani acid phosphatases.

A crude membrane fraction from promastigotes of Leishmania donovani grown in a liquid culture medium containing 20% fetal calf serum was prepared by freeze-thawing, centrifugation (200,000 X g, 30 min), and extraction with 2% (w/v) sodium cholate. After removal of the bile salt by chromatography on a Sephadex G-75 column, the solubilized membrane protein fraction, rich in acid phosphatase activity, was chromatographed on columns containing concanavalin A-Sepharose, QAE-Sephadex, and Sephadex G-150 and G-100. Three distinct acid phosphatases were resolved: the major phosphatase activity (70% of the total) was L-(+)-tartrate-resistant (designated ACP-P1) and corresponds to the acid phosphatase localized to the outer surface of the parasite's plasma membrane; the other two phosphatases (ACP-P2 and ACP-P3) account for the remaining 30% of the particulate acid phosphatase activity, and both of these enzymes are L-(+)-tartrate-sensitive. Using a combination of sucrose density gradient centrifugation, gel filtration chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was determined that ACP-P1 is a 128,000-dalton protein composed of two subunits of 65,000-68,000 daltons. ACP-P1 has an isoelectric point of 4.1, a pH optimum of 5.5, hydrolyzes fructose 1,6-diphosphate, but no other sugar phosphates and dephosphorylates phosphotyrosine, yeast mannan, and the phosphorylated form of rat liver pyruvate kinase. ACP-P2 (pI, 5.4) and ACP-P3 (pI, 7.1) with molecular masses of 132,000 and 108,000 daltons, respectively, are both tartrate-sensitive and are distinguished from each other on the basis of their sensitivity to inhibition by polyanionic molybdenum complexes. These two phosphatases also have their pH optima in the pH 5.0-6.0 range, but have a considerably broader substrate specificity than ACP-P1.

Acid Phosphatase↗

Determination of alkylphosphonic acids using micellar electrokinetic chromatography with laser-induced fluorescence detection and high-salt stacking.

Methyl-, ethyl- and propylphosphonic acids (MPA, EPA, and PPA, respectively) were derivatized with panacyl bromide in dry N,N-dimethylformamide (DMF). After mixing with a high-salt dilution buffer, the derivatives were separated by micellar electrokinetic chromatography in 35 min and detected by laser-induced fluorescence (He-Cd laser excitation at 325 nm and detection at 500 nm). Baseline resolution was achieved using a separation buffer containing 50 mM sodium cholate, 40% (v/v) of acetonitrile and 50 mM borate. Addition of 400 mM NaCl to the dilution buffer allowed the injection time to be increased to 30 s while still maintaining baseline resolution. Limits of detection for MPA, EPA, and PPA were 0.13 microM (12 ppb), 0.13 microM (14 ppb) and 0.14 microM (17 ppb) injected, respectively. The reproducibility of corrected peak area at 15 microM was 3.7 approximately 4.3%.

Chromatography, Micellar Electrokinetic Capillary↗

Purification and characterization of a novel GTP-binding protein with a molecular weight of 24,000 from bovine brain membranes.

At least six GTP-binding proteins (G proteins) with Mr values between 20,000 and 25,000 were extracted from the crude membrane fraction of bovine brain by sodium cholate and purified by successive column chromatographies of Ultrogel AcA-44, phenyl-Sepharose CL-4B, hydroxyapatite, and Mono Q HR5/5. One G protein with a Mr of about 24,000 (24K G) was purified to near homogeneity and characterized. 24K G bound maximally about 0.7 mol of [35S]guanosine 5'-(3-O-thio)triphosphate (GTP gamma S)/mol of protein with a Kd value of about 46 nM. [35S]GTP gamma S binding to this protein was inhibited by GTP and GDP, but not by other nucleotides such as ATP, UTP, and CTP. 24K G hydrolyzed GTP to liberate Pi with a rate of about 40 mmol of Pi/mol of protein/min. 24K G did not associate with the beta gamma subunit of Go. 24K G was distinguishable on sodium dodecyl sulfate-polyacrylamide gel electrophoresis from the ras protein (ras p21) and ADP-ribosylation factor, the G protein with a Mr of about 21,000 serving as a cofactor for the cholera toxin-dependent ADP-ribosylation of Gs. 24K G was not recognized by the antibody against ras p21, ADP-ribosylation factor, the alpha subunit each of Gs, Gi, and Go, or tubulin. These results indicate that 24K G is a novel G protein and suggest that there are multiple forms of G proteins with small Mr values as is the case with the G proteins which have the alpha subunits with Mr values of about 40,000.

Animals↗

Reconstitution of a kidney chloride channel and its identification by covalent labeling.

The basolateral membrane of the thick ascending loop of Henle (TALH) of the mammalian kidney is characterized by its high content of Na+/K(+)-ATPase and a Cl- conductance, which function in parallel in salt reabsorption. In order to reconstitute the Cl- channels, TALH membrane vesicles were solubilized in 1% sodium cholate in buffer containing 200 mM KCl, followed by dilution with soybean lipids (final ratio of protein/detergent/lipid of 1:3:15 in mg) and removal of the detergent by gel filtration on Sephadex G-50. Cl- channel activity in the liposomes was determined by a 36Cl- uptake assay where the accumulation of the radioactive tracer against its chemical gradient is driven by the membrane potential (positive inside) generated by an outward Cl- gradient. The 36Cl- uptake by the KCl-loaded liposomes was dependent on the inclusion of membrane protein and was abolished by valinomycin, indicating the involvement of a conductive pathway. It was also inhibited by 36% by 100 microM 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB). Solubilization of the Cl- channels in cholate was optimal in the presence of 200 mm KCl, but was found to decrease markedly at low ionic strength. SDS-PAGE analysis of the proteins extracted by cholate at high and low salt concentrations showed that the Cl- channel-containing high KCl extract was enriched in the 96 and 55 kDa alpha- and beta-subunits of the Na+/K(+)-ATPase (the major proteins in the membrane preparation) and several minor protein bands. Treatment of the membrane vesicles with the radioactive analogue of DIDS, [3H]2DIDS, labeled primarily a 65 and a 31 kDa protein. The solubilization of the 31 kDa protein by cholate depended markedly on the ionic strength and thus paralleled the solubilization pattern of Cl- channel activity. Furthermore, the labeling of the 31 kDa protein was prevented by nonradioactive DIDS and by NPPB but not by other compounds, indicating that it may be a Cl- channel component.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

Characterization, stability and in-vivo distribution of asialofetuin glycopeptide incorporating DSPC/CHOL liposomes prepared by mild cholate incubation.

In this study, a small triantennary asialoglycopeptide of fetuin (A-F2) was used as a ligand to direct liposomes to hepatocytes. A-F2 was cleaved from asialofetuin, purified, conjugated with fatty acids and incorporated into pre-formed sonicated DSPC/Chol (2:1) liposomes. A mild cholate incubation method for incorporating the A-F2 ligand on pre-formed vesicles was used. In preliminary in vivo experiments 111In3+ encapsulated in A-F2/palmityl liposomes was seen to accumulate in the liver of mice significantly faster than when encapsulated in non-ligand bearing liposomes of the same lipid composition (studied before), justifying further investigation of this system. The presence of the A-F2/fatty acid conjugate in a functional form on the vesicle surface was confirmed by their reversible agglutination in the presence of Ricinus communis agglutinin (RCA120). Effects of ligand incorporation on the vesicle size distribution, z-potential, membrane integrity and stability were monitored. The results demonstrate that highest ligand incorporation was achieved when liposomes and ligand were co-incubated in the presence of 1 mM sodium cholate. Incorporation increased with the length of the fatty acid used for A-F2 conjugation. Ligand-bearing liposomes were demonstrated to be smaller in diameter (about 30%) with a more positive z-potential in comparison to control vesicles while ligand incorporation did not influence the liposome membrane integrity. The size of the ligand-incorporating vesicles was maintained after 24 hours of incubation in isotonic buffer, proving that the vesicles do not aggregate. Although the preliminary biodistribution results may suggest that ligand bearing liposomes are accumulating in the liver, further cell culture, in vivo distribution and especially liver fractionation studies are required in order to clarify the intrahepatic localization of these liposomes and the ability to target liver hepatocytes in vivo.

Animals↗

Preparation and properties of partially purified pulmonary cytochrome P-450 from rabbits.

Cytochrome P-450 from rabbit pulmonary microsomes was purified approximately 32-fold. The purification method involved solubilization of microsomes using sodium cholate, and recovery of cytochrome P-450 in the precipitate formed between 25 to 42% saturation of the digested microsomes with ammonium sulfate in the absence of glycerol. Further purification was achieved by chromatography on DEAE-cellulose and hydroxylapatite using Emulgen 913 as an eluent. Partially purified preparations containing up to 7.4 nmol of cytochrome P-450 per mg of protein were essentially free of NADPH-cytochrome c reductase activity and cytochromes b5 and P-420. However, epoxide hydrase was found to co-purify with cytochrome P-450. The CO-difference spectrum of dithionite-reduced purified cytochrome showed the expected peak at 450 nm. However, the magnitude of the peak was dependent on added microsomal lipid fraction in the assay medium. Purified pulmonary cytochrome P-450 formed typical types I and II substrate difference spectra with benzphetamine and pyridine, respectively. Sodium dodecyl sulfate-gel electrophoresis of partially purified cytochrome P-450 gave two major bands when stained with Coomassie blue. The faster moving band which contained peroxidase activity had an estimated molecular weight of 49,000 +/- 1,200. The cytochrome P-450 fraction, when combined with solubilized pulmonary microsomal NADPH-cytochrome c reductase and lipid fractions, was active in the O-deethylation of 7-ethoxycoumarin and the N-demethylation of benzphetamine.

Animals↗

Purification of cytochrome b-245 from human neutrophils.

The low potential cytochrome b (b-245) of the microbicidal oxidase of phagocytic cells has been purified from neutrophils from patients with chronic myeloid leukaemia. Cells were homogenized in the presence of proteinase inhibitors and centrifuged to remove the cytoplasm. The pellets containing membranes, granules and other organelles (15 mg/ml) were then washed with buffered sodium cholate (5 mg/ml). Residual pellets were subsequently solubilized with the non-ionic detergent Triton N 101 (10 mg/ml) which extracted about 60% of the cytochrome b. About 10% of the cytochrome b was of mitochondrial origin which was removed on a column of n-amino-octyl-Sepharose that did not adsorb cytochrome b-245. Cytochrome b-245 was chromatographed on a column of heparin-agarose and eluted with NaCl to give a peak specific content of 11-16 nmol of cytochrome b-245/mg of protein, representing a 140-200-fold purification with a recovery of 15%. This technique results in the purification of approx. 100-150 nmol of highly purified cytochrome b-245 from (3-5) X 10(11) cells within 4 days. The most purified material gave a broad band with an apparent Mr of between 68 000 and 78 000 on sodium dodecyl sulphate/polyacrylamide gel electrophoresis, but gel filtration indicated an aggregated form of the protein in Triton N101 . Purified protein (14 nmol of haem/mg of protein) did not contain FAD or FMN and had no NADPH-dependent O2--generating activity.

Chromatography, Affinity↗

Characterization and partial purification of a chloride- and calcium-dependent glutamate-binding protein from rat brain.

A glutamate-binding protein was solubilized from rat brain synaptic plasma membranes using sodium cholate. Its properties were characterized after addition of exogenous phospholipids and formation of proteoliposomes. Glutamate binding was dependent on calcium and chloride ions with maximal binding at concentrations of 10(-5) M calcium and 10 mM chloride ions. The effects of the two ions were synergistic rather than additive. In addition, glutamate binding was not affected by inhibitors specific for N-methyl-D-aspartate and kainate receptor subtypes, but was inhibited by quisqualate (Ki = 50 microM) and DL-2-amino-4-phosphonobutyrate (Ki = 1.3 mM). Furthermore, binding was abolished by 100 microM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and 1 mM dithiothreitol. These properties resemble those of the chloride- and calcium-dependent binding site. Starting from the detergent extract, the glutamate-binding protein was purified 123-fold using fractionated ammonium sulfate precipitation, chromatography on hydroxyapatite and on DEAE-Sephacel as sequential purification steps. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified protein fraction showed two major bands migrating with Mr values of 51,000 and 105,000. The properties of the partially purified binding protein were similar to those of the detergent extract. Glutamate binding to the partially purified protein is not due to a sequestration process or product binding to N-acetylated alpha-linked dipeptidase. Thus, the functional role of the binding protein remains to be established.

Animals↗

Molecular morphology of the tetrodotoxin-binding sodium channel protein from Electrophorus electricus in solubilized and reconstituted preparations.

The appearance of detergent-solubilized voltage-regulated sodium channel protein was recently characterized by this laboratory. Negative-staining revealed rod-shaped particles measuring 40 X 170 A. Further studies have suggested that the actual configuration of this protein may be quite different from the rod-shaped structures. Freeze-fracture and freeze-etch images of the protein in reconstituted membranes indicated that the channel is cylindrical with a diameter of 100 A and a minimum length of 80 A. Experiments with two detergent systems (Lubrol-PX and sodium cholate) enabled us to explain the discrepancy between this structure and the rod-shaped particles visualized earlier. Negative staining in either detergent at low pH (4.5) produced rod-shaped structures. As the pH was increased, doughnut-shaped particles, consistent with the structure of the protein in freeze-etch, appeared in negative stain. The tendency of the protein to change shape under different pH conditions appears to be a peculiar property of this protein.

Animals↗

Restoration of calcium transport in the trypsin-treated (Ca+ + Mg2+)-dependent adenosine triphosphatase of sarcoplasmic reticulum exposed th sodium dodecyl sulfate.

When sarcoplasmic reticulum vesicles are exposed to trypsin for 1 min the adenosine triphosphatase (Mr = 102,000) is cleaved to fragments of Mr = 45,000 and 55,000. The purified ATPase, containing both fragments, transports Ca2+ when incorporated into vesicles containing excess phospholipid. The two fragments can only be dissociated in solutions containing 1% sodium dodecyl sulfate (SDS). Ca2+ transport activity is restored in SDS-dissociated preparations in a series of steps involving dilution with 5 volumes of 5% phospholipids in 0.75% sodium cholate, incubation in ice for 30 min, and passage through an anion exchange column. Vesicles formed in this procedure regain high Ca2+ transport activity if they are incubated in SDS solution at 24 degrees for less than 20 min. However, the extent of renaturation diminishes if the vesicles are incubated for longer periods and little acitivity is recovered in vesicles incubated longer than 60 min at 24 degrees.

Adenosine Triphosphatases↗

Detergent-solubilized monomeric and dimeric cytochrome bc1 isolated from bovine heart.

Mitochondrial cytochrome bc1 complex, isolated from frozen bovine heart, was solubilized with five different "non-denaturing" detergents: dodecyl maltoside, octaethylene glycol monododecyl ether (C12E8), Triton X-100, Tween 20, and sodium cholate. The hydrodynamic properties of the solubilized complex III's were then investigated by sedimentation analysis. Complex III exists as a stable and monodisperse dimer when it is solubilized in low ionic strength buffer with a low concentration of any of the five detergents. At pH 7.8, 20 degrees C, the protein sediments as a homogeneous species with an s(obs) of about 14 S. The protein molecular weight of the 14S particle, after correction for bound detergent, is 465,000 +/- 30,000 as measured by sedimentation equilibrium analysis. The aggregation state and/or homogeneity of cytochrome bc1 is strongly dependent upon the concentration of the solubilizing detergent and ionic strength. The enzyme becomes a homogeneous, monomeric complex with a protein molecular weight of 235,000 +/- 20,000 and an s(obs) of 10-10.5 S after it is solubilized in high concentrations of Tween 20 (more than 5 mg/mg of protein) and sodium chloride (more than 0.5 M). However, a heterogeneous mixture of subcomplexes is produced upon solubilization of the complex with high concentrations of the other detergents and 0.5 M NaCl. Monomerization of cytochrome bc1 by Tween 20 and 0.5 M NaCl has no effect on either the spectral properties, the subunit composition, or the enzymatic activity and is reversible since the dimeric 14S particle is regenerated upon removal of the high concentration of salt.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Mitochondrial biogenesis during fungal spore germination. Purification, properties and biosynthesis of cytochrome c oxidase from Botryodiplodia theobromae.

1. Cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) was purified from the mycelial fungus Botryodiplodia theobromae by sodium cholate and ammonium sulfate solubilization, ammonium sulfate fractionation, and DEAE-cellulose chromatography. The purified enzyme contained 6--7 nmol heme a/mg of protein. The specific activity of the purified enzyme was 2.1--2.3 . 10(3) k (min-1) per mg of protein with 15 mumol ferrocytochrome c and at pH 5.9 and optimal phosphate and Tween 80 concentrations (65 mM and 0.1%, respectively). The Km for ferrocytochrome c was determined to be 1.2--1.3 . 10(-5) M, while at infinite substrate concentration the enzyme catalyzed the oxidation of about 60 mumole of ferrocytochrome c/min per mg of protein. Sedimentation behavior and kinetic evidence suggest that the purified enzyme exists as aggregates of the single molecule. The purified B. theobromae cytochrome c oxidase with its 428 nm Soret absorption maximum may be similar if not identical to oxygenated forms of the enzyme from other fungal species. 2. The purified enzyme was shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis to consist of seven polypeptides with the following respective molecular weights: I, 41 000; II, 28 000; III, 19 000; IV, 14 800; V, 12 800; VI, 11 500; and VII, 9300. Biosynthesis studies showed that the three highest molecular weight polypeptides of the enzyme were synthesized on mitochondrial ribosomes, and the four smaller polypeptides were products of cytoplasmic ribosomes.

Cytochrome c Group↗

Dissociation and association rate constants changes following bilirubin binding affinity decreases.

The effect of sulfisoxazole, sodium salicylate, sodium cholate, urea and dimethyl sulfoxide on the kinetics of the bilirubin to human serum albumin at 24 degrees C and pH 7.40 was investigated. A marked decrease of the association constant was obtained. It was due mainly to that of the association rate constant, and might be an additional risk factor to the icteric newborn: when blood bilirubin increases, unbound bilirubin which cannot rapidly associate to albumin may reach a dangerous level, even when its equilibrium concentration is low.

Bilirubin↗

Solubilization of 20S acetylcholinesterase from the chick central nervous system.

The ionic detergent sodium cholate, in the presence of 1 M NaCl, solubilizes a 20S acetylcholinesterase from chick retina and other brain tissues previously extracted with a buffered solution containing 1% Triton X-100 and 1 M NaCl. This 20S acetylcholinesterase appears to be a tailed form of the enzyme which, upon collagenase digestion, is converted to a 22S (mainly) form. This finding suggests that the vertebrate central nervous system does contain asymmetric, collagen-tailed forms of acetylcholinesterase, as is the case in skeletal muscle and cholinergic ganglia.

Acetylcholinesterase↗

[M-cholinoreceptor-mediated inhibition of Na, K-ATPase activity in the myocardial sarcolemma and intestinal smooth muscles by acetylcholine].

Acetylcholine (ACH) produced specific inhibition of Na, K-ATP-ase activity in sarcolemmic preparations of the frog heart (K0.5 = 1 microM), dog atria (K0,5 = 5 microM) and ventricles (K0.5 = 1 microM), and dog small intestinal smooth muscles (K0,5 = 0.5 microM). K0.5 is the concentration causing a half-maximal effect. Atropine (10(-7) = 10(-6) M) blocked the inhibitory effect of ACH. The preparations contained a considerable number of 3H-quinuclidinyl benzilate (3H-QNB) binding sites. Treatment of atrial sarcolemma with a mixture of digitonin and sodium cholate resulted in a substantial decrease in the number of 3H-QNB binding sites in the membrane, while Na,K-ATPase lost responsiveness to ACH. In the presence of 10 microM GTP there was a noticeable decrease in sensitivity of the enzyme to ACH. It is assumed that inhibition of Na, K-ATPase activity by acetylcholine is mediated by muscarinic receptor activation with the involvement in this process of GTP-binding proteins.

Acetylcholine↗

A novel affinity purification of D-1 dopamine receptors from rat striatum.

When rat striatal membranes were pretreated with the sulfhydryl (-SH) modifying reagent, N-ethylmaleimide (NEM) in the presence of the D-1-specific agonist, SKF R-38393, the D-1 dopamine receptor was completely protected from NEM-mediated inactivation. The D-1 receptors, solubilized from these membranes with 1% sodium cholate in the presence of phospholipids, bound with high efficiency (greater than 90%) to mercury-agarose columns. The bound receptors were eluted from the affinity column with a -SH reducing agent, beta-mercaptoethanol. Upon removal of beta-mercaptoethanol from the eluted fractions by inclusion chromatography, the receptor was reconstituted into phospholipid vesicles and assayed for ligand binding activity. The affinity purified receptor exhibited saturable and specific binding of the D-1-specific ligand 125I-SCH 23982, with a Kd of 1.6 nM comparable to that measured in intact membranes and solubilized extracts. The binding capacity of these receptors for 125I-SCH 23982 was 11,000 pmol/mg protein, representing greater than an 8000-fold purification over the starting membrane preparation. The purity of the affinity eluted receptors was estimated to be 78%. The purified receptors retained the pharmacological properties of membrane-bound receptors, including the ability to distinguish between active and inactive enantiomers of specific dopaminergic antagonists. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining revealed the presence of two major polypeptides of 74 and 54 kDa. These two polypeptides were absent in those affinity eluted fractions which did not display 125I-SCH 23982-binding activity and also were not detected in preparations obtained from membranes which were NEM-treated in the absence of D-1-specific agonist. The molecular weights of these polypeptides were similar to those of membrane-bound D-1 receptors, when labeled with a D-1-specific photo-affinity ligand, 125I-8-hydroxy-3-methyl-1-(4-azidphenyl)-2,3,4,5-tetrahydro-1H-3-b enzazepine. These two polypeptides may represent glycosylated and deglycosylated forms of the D-1 dopamine receptor.

Animals↗

Liquid crystal solubilization of cholesterol: potential method for gallstone dissolution.

Solubilization rate and phase equilibrium studies were conducted for cholesterol in aqueous sodium oleate solutions. The components interacted to form a lamellar liquid crystalline phase, and this phenomenon was investigated as a potential method for cholesterol gallstone dissolution. Phase equilibria data for cholesterol-sodium oleate-water showed that the mesophase contained approximately equimolar amounts of cholesterol and oleate with large amounts of water. The cholesterol solubilization rate from a static pellet in sodium oleate solutions was much faster than dissolution in sodium cholate solutions and was independent of oleate concentration from 2.5 to 10%. In these experiments, the medium became a cloudy dispersion of liquid crystalline phase in the micellar solutions. The rate-limiting step in the solubilization process appears to be dispersion of fragments from the liquid crystalline layer on the cholesterol surface. This hypothesis was consistent with the kinetic effects of viscosity, stirring rate, and oleate concentration. By converting cholesterol to a liquid crystalline phase, the solubilization process avoids the limitations for micellar solubility and interfacial resistance which control cholesterol dissolution in bile salt-containing media.

Cholelithiasis↗