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At least 1,063 records · Page 59Linked to original sources
PubMed1979

The effect of exposure to halogenated anaesthetics on liver glutathione levels in rats. An index of hepatotoxicity.

Having studied anaesthetic drug interactions in rats, we report the effects of halogenated anaesthetics on the liver glutathione levels and histology, as well as the results of the enhancement of these effects by microsomal enzyme induction. The anaesthetic agents studied included methoxyflurane, halothane, ethrane, chloroform and fluroxene. While exposure of rats to methoxyflurane, helothane and ethrane produced no significant changes in hepatic glutathione levels, or in liver histology, exposure to chloroform and fluroxene produced marked depression of liver glutathione, especially after microsomal enzyme induction. Furthermore, rats exposed to thses agents after enzyme induction developed gross centrilobular necrosis and died. It is suggested that the study of the effects of any new anaesthetic agent on liver glutathione levels could be a valuable screening test of its hepatotoxic potential, before its clinical trial.

Anesthetics↗
PubMed1986

[Chemistry and pharmacology of prednicarbate (Hoe 777), a halogen-free topical anti-inflammatory active derivative of prednisolone-17-ethyl carbonic acid ester].

Prednicarbate (Hoe 777) is a corticoid without halogenic groups (see formula Fig. 1), showing a remarkably favorable split between topical and systemic anti-inflammatory or rather corticoid effects, which could be proved by means of various animal experiments after dermal and systemic application. The topical efficacy resembles that of current corticoid preparations containing fluorine, but its systemic influence is definitely less.

Administration, Topical↗
PubMed1979

Effect of halogenated benzenes on acetanilide esterase, acetanilide hydroxylase and procaine esterase in rats.

1,2,4-Trichlorobenzene, 1,3,5-trichlorobenzene, hexachlorobenzene, 1,2,4-tribromobenzene, 1,3,5-tribromobenzene and hexabromobenzene were compared for their abilities to induce acetanilide esterase, acentailide hydroxylase and procaine esterase. Except for hexabromobenzene all induced acetanilide esterase whereas the hydroxylation of acetanilide was seen only with the fully halogenated benzenes and with 1,3,5-tribromobenzene. Hepatic procaine esterase activity was increased by the three chlorinated benzenes and 1,2,4-tribromobenzene.

Acetanilides↗
PubMed1979

Synthesis and anti-inflammatory properties of budesonide, a new non-halogenated glucocorticoid with high local activity.

As part of a study of the local anti-inflammatory activity of corticosteroid 16 alpha, 17 alpha-acetals it was found that on acetalization of 16 alpha-hydroxyprednisolone with n-butyraldehyde the two possible epimers were formed in the ratio of 1: 1. The reaction product was resolved by column chromatography on Sephadex LH-20. The isolated epimers were studied by NMR and mass spectrometry. The epimeric mixture of this new non-halogenated corticoid, 16 alpha, 17 alpha-(22R,S)-propylmethylenedioxypregna-1,4-diene-11 beta,21-diol-3,20-dione (budesonide), was shown to have a local antiinflammatory potency comparable to that of fluocinolone acetonide in cotton pellet tests in rats. In contrast, its systemic glucocorticoid activity was found to be 4--7 times lower than that of fluocinolone acetonide, however.

Animals↗
PubMed1977

[Exchange of aromatically bound halogen for OH- and SCH3-groups in metabolising clozapine in the human organism (author's transl)].

8-Chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo-(b,e)(1,4)-diazepine (clozapine, 1) is metabolized in humans by exchange of the aromatic halogen for a hydroxy- or a methylthio-group (compounds 2 and 3). Further metabolites are the N-demethyl derivatives of 2 and 3, the compounds 4 and 5. In addition a clozapine metabolite with the structure 6 with an oxidized piperazine ring was found. The presence of a metabolite with an oxidized sulfur atom is suggested. Possible ways for the formation of these metabolites are discussed.

Clozapine↗
PubMed1982

Evidence for acute cellular changes in human hepatocytes during anesthesia with halogenated agents: an electron microscopic study.

Liver biopsy specimens of 24 patients who had elective laparotomies were studied by electron microscopy for evidence of anesthesia-related toxic changes. All patients were initially anesthetized with nitrous oxide, barbiturate, and narcotic until the laparotomy incision was completed and an initial preanesthesia liver biopsy specimen was taken. Patients were then give, in randomized fashion, maintenance inhalational anesthesia for the duration of the procedure with halothane, fluroxene, or enflurane. Control patients were continued on nitrous oxide, barbiturate, and narcotic. After approximately 60 minutes a second postanesthesia liver biopsy specimen was taken. For each patient, the preanethesia and postanesthesia liver biopsy specimens were compared, in blinded fashion, for evidence of morphologic changes resulting from anesthesia. Ultrastructural changes consistent with hepatic toxicity were present in more than 25% of the cells examined in the postanesthesia specimens in all of the seven patients given halothane, five of the six patients given fluroxene, and one of the five patients given enflurane. None of the six nitrous oxide-barbiturate-narcotic control patients showed toxic changes in postanesthesia specimens. The most prominent toxic change was dilatation of endoplasmic reticulum. Accumulation of intracellular inclusions occurred in some cells, and a small percentage of cells also showed lipid accumulation and mitochondrial swelling. Evidence suggested that exposure to halogenated anesthetics is related to acute toxic subcellular changes in hepatocytes.

Adolescent↗
PubMed1981

Clinical trial of a potent non-halogenated topical steroid, Budesonide.

In a double-blind, randomized multi-centre study, 116 patients with psoriasis have been treated for 1-3 weeks with budesonide ointment (Preferid, Draco/Tika; a subsidiary of AB ASTRA), a new non-halogenated topical steroid. In a series of 11 patients a 0.025% budesonide ointment was significantly superior to placebo. In a second series, of 54 patients, a 0.025% fluocinolone acetonide ointment (Synalar, ICI). In a third series, of 51 patients, a 0.010% budesonide ointment was compared with 0.025% fluocinolone acetonide ointment. No statistically significant difference between these two preparations was found to exist. No adverse reactions were observed.

Administration, Topical↗
PubMed1981

Inhibitory effect of 5-halogenated deoxyuridines on in vitro keratinization of a transformed rat urinary bladder epithelial cell line.

The effect of 5-halogenated deoxyuridines on the keratinization of an in vitro-transformed rat bladder epithelial cell line, BES20B, was studied by a cover slip culture method established previously. 5-Bromodeoxyuridine (BrdU) and 5-iododeoxyuridine (IdU) both showed dose-dependent inhibition of the keratinization. The complete inhibition of keratinization was achieved by BrdU at concentrations higher than 5 microgram/ml. At these concentrations, BrdU reduced the saturation density of the test cells on a cover slip. Removal of BrdU from the culture medium restored the cell growth as well as the keratinization of BrdU-treated cells, suggesting that the effect of BrdU is reversible. The effect of BrdU was abolished by the addition of excess thymidine. A possible mechanism of the anti-keratinization effect of BrdU is discussed in comparison with that of vitamin A.

Animals↗
PubMed1983

High-dose ascorbic acid prophylaxis in workers occupationally exposed to halogenated ethers.

A possible prophylactic effect of ascorbic acid (AA) was studied in a group of 77 workers occupationally exposed to carcinogens bis(chloromethyl) ether and chloromethyl methyl ether. The effect of prophylactic treatment was assessed by cytogenetic analysis of chromosome aberrations, and by determination of blastic transformation and mitotic index in peripheral lymphocytes. Blood samples were taken at the beginning and at the end of 5-month AA prophylaxis. Simultaneously synthetic resin workers and subjects without any occupational exposure were used as controls. Administration of AA in daily doses of 1 g, 5 days per week, significantly decreased the frequency of aberrant cells (AB.C.) from 3.73% to 2.13%, and increased % of blastic transformation (BT) from 59.15 to 67.26 and of mitotic index (MI) value from 1.04 to 1.42. The respective data in synthetic resin workers were 3.65 against 3.52% of AB.C., 55.82 against 63.73% of BT and 0.78 against 1.08 of MI, and in nonexposed subjects 1.64 against 1.88% of AB.C., 52.10 against 55.73% of BT and 1.07 against 1.14 of MI. Smoking habits had no clear-cut effect on detected changes. These study results have confirmed that the risk of genetic injury, if assessed by the frequency of chromosome aberrations in peripheral lymphocytes, was considerably reduced after AA prophylaxis in workers occupationally exposed to halogenated ethers.

Adult↗
PubMed1981

[A method for detection of volatile organic halogenated compounds in human and animal tissues (author's transl)].

A method is described which is suitable for detecting volatile halogenated hydrocarbons boiling from 60 degrees to 150 degrees C in human and animal tissues. Fried tissue samples of 10 grams are homogenized with Na2SO4. Stripped by nitrogen in an 80 degrees C water bath the compounds are sorbed on XAD-2 columns and desorbed by pentane. The pentane extract can directly be analyzed without further clean up, either by gas-liquid chromatography or by microcoulometry. Limits of detection achieved were between 6.2 X 10(-9) g/kg for carbon tetrachloride and 49 X 10(-9) g/kg for 1,1,2-trichloroethane. The recovery in human tissue is 87% as mean value.

Animals↗
PubMed1980

Photodehalogenation of 7- and 8-halogen-substituted flavins. Photochemistry of the reduced flavin chromophore.

Flavodoxin was reconstituted with 8-chloro- and 7-bromo-FMN and p-hydroxybenzoate hydroxylase with the analogous FAD derivatives. In all cases, the spectral properties of the artificial enzymes changed as a result of photoreduction in the presence of ethylenediaminetetraacetate or oxalate as sources of reducing equivalents. The same changes were found to occur on irradiation of the enzymes which had been reduced previously in the dark under anaerobic conditions with dithionite. Using analogous 7- and 8-chlorolumiflavins, the observed changes were shown to be due to a novel photoreaction of the reduced flavin chromophore, in which either the 7- or 8-halogen substituent is eliminated and replaced by a proton derived from the solvent. The same reaction was shown to occur with 7,8-bis-norlumiflavin where 1 deuterium atom was incorporated into the molecule as a result of photoirradiation of the reduced flavin in deuterated medium. In the case of p-hydroxybenzoate hydroxylase, both the 8-chloro-FAD and 7-bromo-FAD enzymes, as well as their 8-nor-FAD and 7-nor-FAD photoproducts, possessed catalytic activity comparable to that of the native enzyme.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1995

Protein ligand interactions 7 halogenated pyridinium salts as inhibitors of acetylcholinesterase from Electrophorus electricus.

The interaction of halo-quaternary pyridinium hydrochloride salts on acetylcholinesterase (AChE, E.C.3.1.1.7) has been investigated. Kinetic analysis has shown that they reflect a non-competitive inhibition with Ki values in the range 8-13 microM and 5-34 microM for chloro- and bromo-substituted salts respectively. Spectrophotometry was used to study the binding of the ligands with the enzyme and Scatchard analysis used to calculate the respective dissociation constants (Kd) and the number of binding sites. The substitution position of the halogen on the pyridine ring also influenced the binding capacity and the Ki values.

Acetylcholinesterase↗
PubMed1993

[Halogen-induced panniculitis caused by potassium bromide].

Necrotizing panniculitis due to potassium-bromide is a drug induced allergic reaction following stimulation of lymphocytes as demonstrated for the first time by a lymphocyte transformation test (LTT). We named the disease "halogen panniculitis" because of similar generally known reactions to iodides and describe the typical symptoms in three own cases. Bromoderma tuberosum tends to be a similar kind of allergy. For the first time pancreatitis to potassium bromide in men has been observed, which has already been described in epileptic dogs treated with potassium bromide.

Adipose Tissue↗
PubMed1977

[Synthesis and antimitotic activity of 3- and 5-halogen substituted bis-(2-aminophenyl)disulfides and corresponding N-alkyl derivatives].

In continuation of previus research on the antimitotic activity of aryldisulfides, the Authors have synthesised 3- and 5-chloro or fluoro substituted bis-(2-aminophenyl)disulfides and some of their 2-N-alkyl derivatives. These compounds were synthesised in order to submit them to biological testing to find any activity caused by halogen substituents on the benzene ring.

Chemical Phenomena↗
PubMed1977

[Determination of the relative iodine concentration in the lumens of thyroid follicles of normal and neotenic Triturus helveticus, and evaluation of the halogen content of the thyroid colloid. Electron microprobe study (author's transl)].

The stable, bound iodine in the thyroid colloid of Triturus helveticus has been studied with the electron microprobe. Some animals show a normal development. Others are accidentally neotenic due to certain ecological conditions. The values of punctate iodine concentrations (CPI) have been computed and expressed in relative units (counts/s). The mean CPI per lumen is very variable from one follicle to another in the same thyroid section. During normal development, the mean CPI per animal is generally higher in metamorphosing individuals than in larvae. During development with neoteny, the mean CPI per animal attains high values if the larval state is maintained in its totality; the CPI decreases in partially metamorphosed animals, but increases again after metamorphosis. The amount of halogen contained in the thyroid colloid has been computed in relative units (colloid iodine pool). Throughout normal development, the pool remains small if the animals have not attained the adult state. In increases considerably in entirely larval neotenic newts, decreases during metamorphosis but increases afterwards. In totally neotenic newts, the thyroid gland receives only a low hypophyseal stimulation and reacts as the thyroid gland of various hypophysectomized Urodeles. Our results pose the problem as to whether TSH regulates the transepithelial iodine flows, which permit the expansion of the colloid iodine pool, when this hormone is secreted at a very low levels.

Animals↗
PubMed1977

Photocontact dermatitis to halogenated salicylanilides and related compounds. Our experience between 1967 and 1975.

We evaluated the role of the halogenated salicylanilides and related compounds in the development of photocontact dermatitis between 1967 and 1975 as seen at the University of California, San Francisco clinic. During this period positive photopatch tests to at least one of these chemicals were detected in 98 patients. Prior to 1967, tetrachlorosalicylanilide and the brominated salicylanilides were the most common offenders. Declines occurred in number of patients with positive photopatch tests and patch tests to these agents as well as the number of patients tested to these agents during this period; ie, almost three times as many people were tested and four times as many had positive photopatch tests in the last six months of 1967 as compared to the first nine months of 1975. The most striking reduction in numbers of patients with positive tests occurred after 1968, but the most notable reduction in the total number of positive photopatch tests occurred after 1970. We concluded that these results were most likely due to removal from the market of the more potent photosensitizing chemicals and increased physician familiarity with the disease process.

Adult↗