Isolation and properties of Newcastle disease virus nucleocapsid. (9/18)

Deoxycholate (DOC) disrupted virions of Newcastle disease virus (NDV), releasing viral nucleocapsids. The nucleocapsids sedimented at about 200S in sucrose gradients and measured from 1.3 to 1.4 mu long by electron microscopy. NDV nucleo-capsids were resistant to pancreatic ribonuclease. These nucleocapsids contained all the 50S ribonucleic acid (RNA) in NDV virions, while virus-associated RNA sedimenting at less than 50S was external to the virions.  (+info)

Role of hydrophilic bile acids and of sterols on cholelithiasis in the hamster. (10/18)

The effect of various dietary additions such as cholesterol, beta-sitosterol, bile acids, and bile acid analogs on gallstone formation was studied in the hamster. Gallstones were formed in 50% of the animals fed a high glucose, fat-free diet. Administration of 0.2% cholesterol or 1% beta-sitosterol had no effect on the incidence of gallstones. Ursodeoxycholic acid (0.5%) and its analog ursodeoxy-oxazoline [2-(3 alpha, 7 beta-dihydroxy-24-nor-5 beta-cholanyl)-4,4-dimethyl-2- oxazoline] were ineffective in preventing gallstones. Hyodeoxycholic acid and hyodeoxy-oxazoline [2-(3 alpha,6 alpha-dihydroxy-24-nor-5 beta-cholanyl)-4,4-dimethyl-2- oxazoline] at the same dosage effectively prevented gallstones, while the trihydroxy bile acid, hyocholic acid, was not effective. Of all the dietary regimens tested, only hyodeoxycholic acid significantly lowered serum cholesterol. The lithogenic diet produced a five-fold increase in hepatic HMG-CoA reductase activity; this activity was not affected by dietary cholesterol or beta-sitosterol. Hyodeoxycholic acid and hyocholic acid feeding increased the reductase activity by an additional 50% while the other bile acids had no effect. beta-Sitosterol doubled the cholesterol 7 alpha-hydroxylase activity whereas hyodeoxy-oxazoline lowered it. Hyodeoxycholic acid-fed animals had significantly lower cholesterol absorption than the animals on the lithogenic diet alone. Biliary cholesterol content increased dramatically in the animals fed the lithogenic diet and was increased still further by ursodeoxycholic acid, hyodeoxycholic acid, and hyodeoxy-oxazoline. These data show that hyodeoxycholic acid and hyodeoxy-oxazoline do not prevent gallstones by inhibiting hepatic cholesterol synthesis or biliary cholesterol secretion.  (+info)

Analysis of fecal bile acids and diet among the Japanese in Hawaii. (11/18)

Fecal samples of 165 Japanese men in Hawaii, age 43 to 74, were analyzed for bile acid content by their conversion to the methyl ester and the trimethylsilyl ether derivative followed by separation on a gas chromatograph. The arithmetic mean of total bile acids for the 165 specimens was 10.96 mg/g dry weight feces. Each of the following bile acids was detectable in over 77% of the fecal specimens: cholic, deoxycholic, lithocholic, and cholanic acid. The intake of Western foods was not positively correlated with the fecal content of secondary or modified bile acids, even though other workers have observed that these bile acids predominated in persons from Westernized countries. Two of the Japanese foods were negatively correlated with the levels of modified bile acids, which suggested that these foods contributed to a decrease in modified bile acids in fecal specimens. Fecal bile acid measurements appeared to be associated with age, but not with weight, height, or serum cholesterol levels.  (+info)

Radiation dosimetry of two new tellurium- 123m-labeled adrenal-imaging agents: concise communication. (12/18)

The absorbed radiation doses to humans from 23-(isopropyl[123mTe]telluro)-24-nor-5 alpha-cholan-3 beta-ol (Te-123m-23-ITC) and 24-(isopropyl[123mTe]telluro)-chol-5-en-3 beta-ol(Te-123m-24-ITC) have been calculated, based on rat biological data, to assess the relative radiation risks to humans from these two new adrenal-imaging agents. The estimated radiation doses to several critical organs have been compared with dose estimates for a variety of other radiolabeled steroids that have been designed as adrenal-imaging agents. Dose estimates to selected organs from Te-123m-23-ITC are as follows (rad/mCi): adrenals 98; ovaries 8.0; liver 1.6. Similar estimated values for Te-123m-24-ITC are: adrenals 210; ovaries 13; liver 2.0. The radiation dose estimates for these two agents are comparable to the calculated radiation doses from 6 beta-[(methyl[75Se]seleno)methyl]-19-nor-cholest-5(10)-en-3 beta-ol (Scintidren) and 19-[131I]iodocholest-5-en-3 beta-ol (NP-59), two agents currently in clinical use for the diagnosis of adrenal disease.  (+info)

The specificity of a 7 alpha-hydroxy steroid dehydrogenase from Escherichia coli. (13/18)

1. Thirty-eight steroids were tested as substrates for a 7 alpha-hydroxy steroid dehydrogenase preparation from a strain of Escherichia coli; an improved method of making the crude enzyme is described. 2. Steroids having a 7 alpha-hydroxyl group in the molecule were substrates except (a) when the 5 beta-cholan-24-oic acid side chain was shortened to less than four carbon atoms and (b) in certain cases when sulphate ester groups were present in the molecule. 3. For testing with the enzyme, a new specimen of 7 alpha-hydroxy-3,12-dioxo-5 beta-cholan-24-oic acid was made, which had properties different from those previously described.  (+info)

3 alpha, 7 alpha, 12 alpha-trihydroxy-24-nor-5 beta-cholan-23-sulfonate: synthesis and suitability for the study of cholate transport. (14/18)

In order to facilitate the study of transport processes of unconjugated C-24 bile salts, simple syntheses of 3 alpha, 7 alpha, 12 alpha-trihydroxy-24-nor-5 beta-cholan-23-sulfonate (norcholansulfonate) and 3 alpha, 7 alpha, 12 alpha-trihydroxy-24-nor-5 beta-[7 beta 5H] cholan-23-sulfonate were devised. The hydrophilic-hydrophobic properties of norcholansulfonate, as determined by its chromatographic behavior as well as by its partition between l-octanol and water, are more similar to those of cholyltaurine than to those of cholate. Self-association of norcholansulfonate in phosphate buffer, pH 7.4, with an ionic strength of 150 mM begins at a concentration of about 1 mM, comparable to that of cholyltaurine and cholate, as determined by spectral changes in fluorescence emissions of {N-[7-(4-nitrobenzo-2-oxa-1, 3-diazol)]-7b-amino-3a, 12a-dihydroxy-5b-cholan-24 - oyl}-2'-aminoethanesulfonate (7 beta-NBD-NCT). The apparent CMC value obtained from solubilization of the dye Orange OT, 8.5 mM, is comparable to that of cholytaurine. 7.5 mM, and lower than that of cholate, 9.5 mM. Norcholansulfonate is readily taken up by rat liver and completely excreted unmetabolized into bile with about the same secretion maximum (Tm) as cholyltaurine. Biliary excretion of norcholansulfonate is inhibited by cholyltaurine, and, vice versa, norcholansulfonate inhibits cholyltaurine secretion. Concerning metabolism and excretion, norcholansulfonate with the sulfonate group in the position where cholate has the carboxylate group should behave as an appropriate cholate analogue in mediated transport processes.  (+info)

Uptake of 3 alpha, 7 alpha, 12 alpha-trihydroxy-24-nor-5 beta-cholan-23-sulfonate into isolated rat hepatocytes by three transport systems. (15/18)

Uptake of norcholansulfonate (3 alpha, 7 alpha, 12 alpha-trihydroxy-24-nor-5 beta-cholan-23-sulfonate), an isogeometric analogue of cholate into isolated rat liver hepatocytes occurs only by saturable transport. In order to identify the transport systems involved, uptake of norcholansulfonate was studied using 7 beta-NBD-NCT ({N-[7-(4-nitrobenzo-2-oxa-1,3-diazol)]-7 beta-amino-3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl})-2'-aminoethanesulfonate) as a competing substrate. For transport of both bile salt derivatives, which mutually inhibit their mediated transport competitively, the existence of at least three transport systems must be assumed. Uptake studies using the cloned hepatic Na+/cholyltaurine cotransporting polypeptide stably expressed in CHO cells (Chinese hamster ovary cells) showed that both bile salt derivatives were transported and furnished the definite KT values of this single transport system and the ratio of the maximal uptake velocities. On the basis of these data, uptake of both bile salt derivatives into rat hepatocytes and their mutual competitive inhibition could be analyzed for three transport systems. The maximal flux rates J2 and the half-saturation constants KT2 in the presence of Na+ (143 mM) are for norcholansulfonate: J1(Na+ 143) = 1.0 +/- 0.2 nmol/(min . mg protein), KT1(Na+ 143) = 15 +/- 4 microM, J2(Na+ 143) = 0.5 +/- 0.2 nmol/( protein), KT2(Na+ 143) = 15 +/- 2 microM, J3(Na+ 143) = 0.5 +/- 0.2 nmol/( protein), KT3(Na+ 143) = 60 +/- 15 microM, and for 7 beta-NBD-NCT J1(Na+ 143) = 0.14 +/- 0.04 nmol/( protein), KT1(Na+ 143) = 3.1 +/- 0.5 microM, J2(Na+ 143) = 0.014 +/- 0.005 nmol/( protein), KT2(Na+ 143) = 21 +/- 2 microM, J3(Na+ 143) = 1.0 +/- 0.1 nmol/( protein), KT3(Na+ 143) = 190 +/- 25 microM. The kinetic parameters are in accordance with the assumptions that the cloned Na+/cholyltaurine cotransporting polypeptide represents transport system 2 and that the kinetically identified additional transport system 1 is either strictly or partially Na(+)-dependent.  (+info)

Synthesis of 11, 12-2H2- and 11, 12-3H2-labeled chenodeoxycholic and lithocholic acids. (16/18)

Deuterium- and tritium-labeled chenodeoxycholic acid and lithocholic were prepared by catalytic reduction of their respective delta11 derivatives. Structures of the intermediates and their isotopic purity were verified by chemical ionization and electron impact mass spectrometry and by nuclear magnetic resonance spectroscopy. Experimental conditions for reductive deuteration were defined which gave complete reduction of the olefin and a product of high isotopic purity. Conditions for optimal tritiation were developed with which little exchange of protons with the solvent occurred; the product had high specific activity. To test biological stability of the label, the 3H-labeled chenodeoxycholic acid was administered simultaneously with 14C-labeled chenodeoxycholic acid to two healthy subjects and the 3H/14C ratio in bile was determined daily for several days. The ratio remained identical to that administered, suggesting that the 11,12-3Hlabel in chenodeoxycholic acid is stable during enterohepatic cycling and can be used for valid estimates fo bile acid kinetics in many by the isotope dilution technique.  (+info)