bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of ocular toxicity in dogs during 6 months' exposure to a potent organophosphate
Authors: Atkinson John E. , Bolte Henry F. , Rubin Lionel F. , Sonawane Meena 
Published: October 2006

AbstractExposure to anticholinesterase pesticides has been associated with the development of ocular toxicity in humans and animals, ranging from blurred vision to degeneration of the optic nerve. Based on the concern for human safety, the US Environmental Protection Agency has recently required additional studies for this class of compounds, focusing on biochemical, functional and histopathological evaluation of the ocular system. This study was designed to determine the effects on the eye of ethyl parathion, a highly toxic organophosphate, when administered orally to 30 beagle dogs (five of each sex per group) at doses of 2.4, 7.9 or 794 μg kg−1 day−1 for 6 months. Control animals received corn oil. Routine ophthalmoscopic and slit lamp examinations, refraction and intraocular pressure determinations and electroretinograms were performed as functional assessments at various intervals over the study. Plasma and erythrocyte cholinesterase were determined at weeks 1, 6, 14, 20 and 26, while brain, retinal and ocular muscle cholinesterase were measured at week 26 only. Histopathological examination of the retina, optic nerve, ocular muscle and ciliary body was conducted at termination.Plasma and erythrocyte cholinesterase was markedly depressed at 7.9 and 794 μg kg−1 day−1 as early as week 1. Retinal cholinesterase was decreased (37–55%) from control values in the 794 μg kg−1 day−1 group only. Ocular muscle cholinesterase was comparable in treated and control groups at termination. No functional impairment of the eye was noted over the 6‐month study. Based on refractive indices, intraocular pressure and evaluation of electroretinograms, it was concluded that administration of ethyl parathion at doses up to 794 γg kg−1 day−1 for 6 months does not produce functional or histopathological changes indicative of ocular toxicity. Cholinesterase inhibition, observed early in the study, does not appear to be related to the development of ocular toxicity.
Induction of cytochrome P‐450 isozymes by hexachlorobenzene in rats and aromatic hydrocarbon (Ah)—Responsive mice
Authors: Linko Patricia , Yeowell Heather N. , Gasiewicz Thomas A. , Goldstein Joyce A. 
Published: October 2006

AbstractHexachlorobenzene (HCB) differs markedly from other chlorinated benzenes (CBs) as an inducer of cytochrome P‐450 (P‐450) isozymes as determined by radioimmunoassay and immunoblotting. At > 99% pure, HCB induced both the phenobarbital‐inducible forms, cytochromes P‐450b + e (70X), and the 3‐methylcholanthrene‐inducible forms, cytochromes P‐450c (58X) and P‐450d (8X), in rat liver microsomes. The concentration of P‐450d was considerably greater than that of P‐450c in HCB‐induced rat liver. In contrast to HCB, all lower chlorinated benzenes tested were PB‐type inducers. Hexachlorobenzene increased the amounts of translatable messenger RNAs (mRNAs) for P‐450b, P‐450c, and P‐450d in rat liver polysomes, suggesting that it increases the synthesis of these proteins. Evidence that HCB interacted with the putative Ah receptor for 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) was equivocal. Western blots of liver microsomes from Ahresponsive C57BL/6J (B6) and nonresponsive DBA/2J (D2) mice demonstrated that HCB produced a large increase in P3‐450 and a very small increase in P1‐450 in the responsive strain. The increase in P1‐450 was not observed after HCB administration to nonresponsive mice, but a small increase in P3‐450 was noted. These findings suggested that HCB may act through the Ah receptor. However, HCB was at best a very weak competitor for specific binding of [3H]‐TCDD to the putative receptor in rat or mouse hepatic cytosol in vitro, producing decreases in binding of [3H]‐TCDD only at very high concentrations (10−6 to 10−5 M).
Hepatic fatty acid conjugation of 2‐chloroethanol and 2‐bromoethanol in rats
Authors: Kaphalia Bhupendra S. , Ansari G. A. S. 
Published: October 2006

AbstractTo study the formation of fatty acid conjugates of 2‐chloroethanol (2‐CE) and 2‐bromoethanol (2‐BE), rats were administered (by gavage) 50 mg/kg of 2‐CE and 2‐BE in mineral oil and sacrificed on fifth day of the treatment. Hepatic microsomal lipids were extracted, and the fatty acid esters were separated by preparative thin‐layer chromotography. The ester fraction was further purified by reverse‐phase, high‐performance liquid chromatography and analyzed by ammonia chemical ionization mass spectrometry. Pseudomolecular ions (M + N+H4, base peak) at m/z 336/338, 362/364, and 364/366 in a ratio of 3:1 and 380/382 and 408/410 in a ratio of 1:1 confirmed the in vivo formation of 2‐chloroethyl palmitate, 2‐chloroethyl oleate, 2‐chloroethyl stearate, 2‐bromoethyl palmitate, and 2‐bromoethyl stearate, respectively. These results demonstrate the formation of fatty acid conjugates of 2‐CE and 2‐BE in vivo. These fatty acid conjugates may be retained in the body for a longer time and cause toxic manifestations.
Hemoglobin degradation lipid peroxidation, and inhibition of na+/k+‐atpase in rat erythrocytes exposed to acrylonitrile
Authors: Farooqui Mohammed Y. H. , Mumtaz Mohammad M. , Ghanayem Burhan I. , Ahmed Ahmed E. 
Published: October 2006

AbstractThe effect of acrylonitrile (VCN) on erythrocyte lipid metabolism was investigated in vitro in metabolically active red cells from male Sprague‐Dawley rats containing three types of hemoglobins: oxyhemoglobin, methemoglobin, and carbon monoxyhemoglobin. VCN at the concentration of 10 mM rapidly depleted erythrocyte glutathione (GSH) (75% of control) and induced lipid peroxidation (274% of control). Degradation of oxy‐ and methemoglobin was directly proportional to the extent of lipid peroxidation (r = 0.89). Addition of glucose to the incubation medium decreased hemoglobin degradation while it slightly increased VCN‐induced lipid peroxidation. The highest amount of lipid peroxidation occurred in erythrocytes containing carbon monoxyhemoglobin and glucose. In the isolated red cell membranes incubated with 10 mM VCN, the lipid peroxidation was 400% of controls. VCN (25 mM) noncompetitively inhibited erythrocyte membrane Na+/K+‐ATPase activity and the degree of inhibition was inversely proportional to the reaction temperature (r = −0.88). These findings indicate that the VCN induced hemoglobin degradation and lipid peroxidation are two extremes of a spectrum of oxidative damage in red cells leading to a change in physical state of membrane structure causing inhibition of adenosine triphosphatase (ATPase) activity.
Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara
Authors: Sharma Om P. , Dawra Rajinder K. , Pattabhi Vasantha 
Published: October 2006

AbstractLantadene A (22 β‐angeloyloxy‐3‐oxoolean‐12‐en‐28‐oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod‐shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x‐ray diffraction of form I showed sharp peaks whereas form II did not contain distinct peaks. From single‐crystal three‐dimensional x‐ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was nontoxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity.
Isolation and characterization of mitochondrial acyl‐coa: Glycine n‐acyltransferases from kidney
Authors: Kelley Michael , Vessey Donald A. 
Published: October 2006

AbstractWhen bovine kidney mitochondria were assayed in the presence of Triton X‐100, they were found to contain glycine N‐acyltransferase activity toward the CoA‐adducts of benzoate, butyrate, isovalerate, naphthylacetate, phenylacetate, and salicylate. Heptanoyl‐CoA activity was masked by high acyl‐CoA hydrolase activity. All activities found in detergent‐lysed mitochondria, and also that toward heptanoyl‐CoA, could be released in soluble form by repeated cycles of freeze‐thawing. Activity in the particle‐free lysate decreased in the order: phenylacetyl‐CoA >benzoyl‐CoA >salicylyl‐CoA >butyryl‐CoA >naphthylacetyl‐CoA >heptanoyl‐CoA >isovaleryl‐CoA. This is quite different from liver, where the activity toward the arylacetic acids is much lower and the other activities are higher. This reflects a major difference in the relative expression of the aralkyl and arylacetyl transferases between liver and kidney. The phenylacetyl‐CoA and naphthylacetyl‐CoA activity purified with a single protein which is termed the arylacetyl transferase. This enzyme was similar to the hepatic arylacetyl transferase in terms of its sensitivity to sulfhydryl reagents, response to cations, and molecular weight (33,500). Activity toward benzoyl‐CoA also purified as a single form which was similar to the hepatic form in its molecular weight (34,000), response to cations, and kinetic properties. Conditions leading to the inhibition of this kidney form and also the hepatic form by p‐mercuribenzoate are described.
The contribution of electrophilic and radicalic intermediates to phospholipid adducts formed by halomethanes in vivo
Authors: De Curtis Valentina , Gemma Simonetta , Sbraccia Maria , Testai Emanuela , Vittozzi Luciano 
Published: October 2006

AbstractThe different production of phosgene and free‐radicals from CHCl3 and CCl4 was determined in vitro and in vivo, by measuring the regioselective binding of the two intermediates to phospholipid (PL) molecules. Results clearly indicated that this assay can be successfully used to selectively detect electrophilic and radicalic metabolites produced in vivo and selectively quantitate their adducts. The in vivo biotransformation of CCl4, similarly to the in vitro situation, resulted in the formation of radicals only, the contribution of phosgene to the structural damage of PL being negligible. These findings allowed us to rule out the hypothesis of substantial formation of radicalic intermediates from CHCl3 in phenobarbital (PB)‐pretreated Sprague—Dawley (SD) rats, derived from in vitro data. While the role of reduced glutathione (GSH) in preventing COCl2‐derived damages seems to be less important in vivo than in vitro, it is not possible to rule out the action of radical scavenging systems in decreasing the level of adducts with fatty acyl chains (FC) of PL measured in vivo.
Sythesis of deuterium and tritium labeled psoralens
Authors: Isaacs Stephen T. , Rapoport Henry , Hearst John E. 
Published: October 2006

AbstractDeuterium and tritium labeled 4,5′,8‐trimethylpsoralen (), psoralen (), and angelicin (), have been prepared by D2O and T2O exchange with specific activities of 228‐253 mCi/mmol. Tritium labeled 4,5′,8‐trimethylpsoralen () with a specific activity of 17.6 Ci/mmol was prepared by catalytic reduction with tritium gas followed by dehydrogenation. Tritiated 4′‐hydroxymethyl‐4,5′,8‐trimethylpsoralen () with a specific activity of 12.0 Ci/mmol was obtained by reduction of the corresponding aldehyde with sodium borotritide and elaborated to 4′‐aminomethyl‐4,5′,8‐trimethylpsoralen () (12.0 Ci/mmol) by conversion of to the chloromethyl derivative followed by the Gabriel synthesis. Tritium labeled 8‐methoxypsoralen () was prepared by demethylation of unlabeled to the phenol followed by methylation with tritiated methyl iodide.
3‐[125I] Iodo‐4‐hydroxyphenobarbitone for use in radioimmunoassay
Authors: Mason P A , Law B 
Published: October 2006

AbstractA method is described for the preparation of a barbiturate derivative, 3‐iodo‐4‐hydroxyphenobarbitone, labelled with [125I]iodine. The structure of the compound was confirmed by synthesis and purification of the [127]iodine derivative followed by mass spectral studies. The [125I]iodine labelled barbiturate has proved to be chemically stable and has been shown to bind to a barbiturate antiserum. It should, therefore, prove to be very useful for the development of a radioimmunoassay for barbiturates.
Economical syntheses of 3H‐2H and 14C‐labeled ethyl acetates
Authors: Alvarez Francisco J. , Kovach Ildiko M. , Schowen Richard L. 
Published: October 2006

AbstractTritium and 14C‐labeled isomers of ethyl acetate are excellent substrates for competitive dual‐labeled radioactive isotopic measurements of β‐deuterium and β‐tritium isotope effects. Methods are given for preparation of the ethyl esters of acetic acid‐2‐3H, acetic acid‐2‐14C, and acetic acid‐2,2‐2H2‐2‐3H, and of the acetic acid ester of ethanol‐l‐14C from the least costly labeled precursors in high purity (yield 70‐80%) on the mmole scale.
Synthesis of tritium‐abeled fosfomycin
Authors: Mertel Holly E. , Meriwether Henry T. 
Published: October 2006

AbstractTritium gas was used as a labeling agent for the preparation of [1,2−3H]fosfomycin. Introduction of tritium into a precursor, the synthesis including resolution of the intermediate racemic 1,2‐epoxypropylphosphonic acid, and preparation of both amine and calcium salts of the labeled antibiotic are described.
Synthesis of dimethyl 5, 5, 6, 6 (2H4)‐2‐oxoheptylphosphonate, a deuterium labelled prostaglandin intermediate
Authors: Meese Claus O. , Borstel Bernd 
Published: October 2006

AbstractThe synthesis of the specifically labelled versatile prostaglandin intermediate 1b is described which involves the preparation of 2,2,3,3 (2H4)butyliodide 6b via homogenous catalytic deuteration of the acetylene 4. Examples for the preparation of prostaglandins and extensive spectroscopic data are included.
Synthesis of radioactively methyl‐labelled (l)‐carnitine
Authors: Ingalls Stephen T. , Hoppel Charles L. , Turkaly Julia S. 
Published: October 2006

AbstractCommercial (l)‐carnitine chloride was N‐demethylated by the action of sodium benzenemercaptide in warm N,N‐dimethylformamide. The product 4‐(N,N‐dimethylammonio)‐3‐hydroxybutanoic acid chloride salt was isolated in good yield by ion exchange chromatography. Methylation of the product by 14C ‐iodomethane in dry methanol produced biologically active 4‐N‐ Me‐14C ‐(l)‐carnitine chloride of high specific activity in excellent yield.
Synthesis of 14C‐labeled 10,11‐epoxyfarnesyl diazoacetate, a potential photoaffinity labeling reagent for insect juvenile hormone binding proteins
Authors: Krafft Grant A. , Reich Marvin F. , Katzenellenbogen John A. 
Published: October 2006

AbstractThe synthesis of [14C]‐10,11‐Epoxy‐(2E,6E)‐farnesyl diazoacetate in one vessel, starting from [14C]‐glyoxylic acid, is described. This compound is useful as a potential photoaffinity labeling agent for juvenile hormone binding sites.
Synthesis of (2R,S)‐ [2‐2H] and [2,3‐2H] tryptophan
Authors: Santaniello Enzo , Ravasi Manuela , Astori Franca 
Published: October 2006

Abstractα‐Deuterated tryptophan was prepared either by exchange of the α‐hydrogen of tryptophan or by hydrolysis and decarboxylation of ethyl 2‐formamido‐2‐carbethoxy‐3‐indole propionate, followed by treatment with CH3COO2H. α,β‐Dideuterated tryptophan was in turn synthetized from ethyl‐α‐acetamido‐indole‐3‐acrylate, by catalytic deuteration (2H2/Pd‐C) and alkaline hydrolysis (NaO2H/2H2O).
Synthesis and purification of methyl‐13C fluoride
Authors: Cohen Isaac , Shulman Jan , Popowicz Anthony , Ishida Takanobu 
Published: October 2006

AbstractA 20 mmole quantity of methyl‐13C fluoride at a 13C‐enrichment level of 90% was prepared by a two‐step synthesis starting with methanol‐13C. The overall yield was 60% of methanol used. A series of gas‐chromatographic treatments using Ascarite, silica gel, and Chromosorb‐102 columns yielded a highly purified methyl fluoride in which the major impurities were less than 10 parts per million of carbon dioxide and 10 parts per million of methyl chloride.
A general procedure for the preparation of α, β labeled amino acids
Authors: Lemaster David M. , Richards Frederic M. 
Published: October 2006

AbstractThe α and β hydrogen exchange reactions catalyzed by pyridoxal have been applied to ten of the common amino acids to prepare α, β deuterated derivatives. The exchange and isolation procedure allows for numerous different samples to be processed in parallel. The deuteration at the α position range from 96 to 99% while the β deuteration levels range from 93 to 97% except for lysine (91%) which exchanges more slowly presumably due to interference of the ϵ‐amino group. The standard procedure produces approximately a gram of deuterated product for all samples except tyrosine (0.15 g) with yields from 70 to 85% using only 15 milliliters of 2H2O. The procedure has been scaled up directly to 100 millimoles for the case of alanine with virtually identical deuteration and product yield.
Synthesis of deuterated vitamin B6 compounds
Authors: Coburn S. P. , Lin C. C. , Schaltenbrand W. E. , Mahuren J. D. 
Published: October 2006

Abstract3‐Hydroxy‐4‐(hydroxymethyl)‐5‐(hydroxymethyl‐d2)‐2‐methylpyridine(pyridoxine‐d2) was prepared by reduction of α4‐3‐0‐isopropylidene‐5‐pyridoxic acid with lithium aluminum deuteride. Deuterium was inserted in the 2‐methyl group using base catalyzed exchange between deuterium oxide and N‐benzyl pyridoxine. Pyridoxine‐d2 was converted to pyridoxal, pyridoxamine, pyridoxic acid, pyridoxine phosphate, pyridoxal phosphate, and pyridoxamine phosphate. After acetylation the nonphosphorylated forms could be analyzed by gas chromatography‐chemical ionization mass spectroscopy.
Preparation of all‐trans‐retinal‐11‐3H and all‐trans‐retinyl‐11‐3H acetate
Authors: Kaegi Hans H. , Bupp James E. , Degraw Joseph I. 
Published: October 2006

Abstracttrans‐Ionylideneacetaldehyde‐1‐3H (3) was obtained by reduction of unlabeled aldehyde 1 with lithium borotritide, followed by reoxidation of the tritio alcohol 2. Condensation of aldehyde 3 with diethyl 3‐cyano‐2‐methylprop‐2‐enylphosphonate (7) afforded retinonitrile‐11‐3H (8) which was smoothly reduced to trans‐retinal‐11‐3H (9) with diisobutylaluminum hydride. Reduction of retinal (9) with lithium borohyride followed by acetylation gave retinyl‐11‐3H‐acetate in excellent yield.
Synthesis of 14C‐labelled fluphenazine esters
Authors: Zólyomi G. , Tóth I. , Toldy L. 
Published: October 2006

AbstractFluphenazine labelled with 14C at the 3‐propyl position was prepared. Starting from K14CN, 3‐chloropropyl p‐toluenesulfonate (7) was synthesized via 3‐chloropropionic acid (4) intermediate and coupled with 2‐trifluoromethylphenothiazine. The phenothiazine derivative (8) obtained was converted into 1a, from which various long acting esters (1b, 1c, 1d) of labelled fluphenazine were prepared for comparative pharmacokinetic studies.
Regioselective deuteriation kinetics of 2‐, 4‐, and 6‐methyl groups in D2O solutions of pyrylium and N‐methylpyridinium perchlorates possessing also 3‐methyl or 3‐phenyl groups
Authors: Balaban Alexandru T. , Uncuta Cornelia , Chiraleu Filip 
Published: October 2006

AbstractBy 1H‐NMR it was found that 2, 3, 4, 6‐tetramethylpyrylium perchlorate (I) in D2O undergoes isotopic exchange at the 2, 4, and 6‐methyl groups with relative rates 5 : 40 : 1, respectively (assignments of α‐methyl NMR signals were substantiated by unambiguous synthesis). If the 3‐methyl group is replaced by a 3‐phenyl group, the relative rates for the pyrylium salt III are 2.5 : 49 : 1, respectively (in D2O + CD3OD). On the other hand, the relative rates for the 2, 4, and 6‐methyls in 1,2,4,6‐tetramethyl‐3‐phenylpyridinium perchlorate are 12 : 1 : 4, respectively (in D2O + CD3OD + NaOD). These rate differences allow the preparation of selectively deuteriated pyrylium or pyridinium salts, and of other aromatic or heterocyclic compounds starting from pyrylium salts with selectively deuteriated side‐chains.
An improved synthesis of catechol‐U‐14C
Authors: Heys J. R. , Chew E. H. , Saugier J. H. 
Published: October 2006

AbstractThe high yield, four‐step synthesis of catechol‐U‐14C from benzene‐U‐14C is described. Intermediates in the preparation include phenol‐U‐14C and o‐methoxyphenol‐U‐14C [guaiacol‐(phenyl‐U‐14C)].
A comparative study of radioiodination of simple aromatic compounds via N‐halosuccinimides and chloramine‐t in TFAA
Authors: Youfeng He , Coenen H. H. , Petzold G. , Stöcklin G. 
Published: October 2006

AbstractA comparative study of radioiodination of simple aromatic compounds using N‐chlorosuccinimide (NCS), N‐bromosuccinimide (NBS), N‐chlorotetrafluoro‐succinimide (NCTFS) and Chloramine‐T (CAT) has been carried out in trifluoroacetic anhydride (TFAA) as an aprotic solvent. Optimization of the iodination procedure has been performed using anisole as the model substrate. A fast and simple “one‐pot” synthesis via NCTFS, NCS or CAT leads to iodoanisoles with a radiochemical yield of about 70 %. For comparison, toluene and benzene have also been radioiodinated.
The deuteration of the histones of physarum polycephalum as a step towards the preparation of selectively deuterated nucleosome core particles
Authors: Carpenter B. G. , Sewell F. M. 
Published: October 2006

AbstractPhysarum polycephalum can be grown in shake flask culture where all of the peptone component of the feed stock has been replaced by a deuterated algal hydrolysate. These conditions give approximately 35% overall deuterium incorporation into the basic nuclear proteins. This level of incorporation, together with the maintenance of a reasonable maximum growth, show P. polycephalum to be a convenient system for the preparation of nucleosome core particles with selectively deuterated histones. Selectively deuterated core particles offer considerable advantages over uniformly protonated ones when structural studies using neutron scattering are carried out.A combination of proton and deuterium magnetic resonance spectroscopy shows that under the conditions so far studied the deuterium incorporation is not uniformly distributed throughout the amino acid residues of the proteins. A 60% deuteration of the terminal apolar methyl groups is accompanied by only 28% deuteration of the hydrogen atoms bound to the α‐carbon.Our observation that α‐carbon hydrogens are exchanged in vitro reactions with 2H3O+, albeit at elevated temperature, could well indicate these hydrogens are exchanged in vivo with the solvent water of the growth medium. Suggestions are made as to other possible variations in feed stock components which could lead to a higher overall levelof deuterium incorporation.Deuteration ‐ Physarum polycephalum ‐ neutron scattering ‐ histones ‐ nucleosome core particles.
Preparation of multitritiated arenes
Authors: Cacace Fulvio , Speranza Maurizio , Wolf Alfred P. , Ehrenkaufer Richard 
Published: October 2006

AbstractThe decay technique, currently applied to the study of ionic processes in gaseous and liquid systems, requires multitritiated precursors to generate labeled daughter ions. The preparation of three such precursors, namely C63HxH6−x, C63HxH5−xCH3, and C6H5C3H3−x is described. The ring–labeled precursors were obtained from the cyclization of C23H2, and respectively of a C23H2/propyne mixture, carried out at 25°C over a K2CrO4–promoted silica–alumina catalyst. The side–chain tritiated toluene was prepared by allowing 3H2O and benzotrichloride to react over a Zn mirror at 200°C. Details of the procedures employed for the radiometric and the isotopic analysis of the multilabeled products are reported.