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Biomedical subjects

D J Ecobichon

Publications and source records attributed to D J Ecobichon.

At least 55 records · Page 3Linked to original sources
PubMed1980

Responses of rodent hepatic, renal and pulmonary aryl hydrocarbon hydroxylase following exposure to cigarette smoke.

Using the British-American Tobacco Co. (B.-A.T.)-Mason inhalation system which releases a precisely-calibrated dilution of tobacco smoke into a chanber, male and female rats, guinea pigs, hamsters and gerbils were exposed to the optimum smoke concentration found to induce rat renal aryl hydrocarbon hydroxylase (AHH) (40 puffs of a 1 : 5 dilution of smoke from cigarettes prepared from a blend of Canadian flue-cured tobaccos). The tissue activity was measured in 9000 g supernatants of homogenates of lung, liver and kidney 6 h following exposure. Cigaratte smoke was found to be a potent inducer of AHH, dilutions as high as 1 : 40 inducing this enzyme in rat kidney. Marked tissue, sex and species differences in basal AHH were observed. Induction up to 6-fold, was observed only in lung and kidney of male and female rats. In hamsters and gerbils, lung AHH was induced in both sexes but only renal AHH in female hamsters. In male and female guinea pigs, only the renal AHH was induced some 5-fold. Hepatic AHH was not inducible in any of the species studied. The analysis of changes in AHH activity in a responsive species and tissue(s) could be a valuable technique for the quantitative evaluation of biological effects of low concentrations of cigarette smoke.

Animals↗
PubMed1980

Subacute toxicity of technical fenitrothion in male rats.

Male CD-strain rats (100--125 g) received fenitrothion by oral gavage (2.5, 5.0, 10.0 or 20.0 mg/kg/day) for 30 consecutive days. Control animals received equivalent volumes of taurocholate vehicle. Animals were killed at 8, 15, 22 and 30 days during treatment and at 8, 15, 29, 57 and 85 days after terminating treatment. The brain plasma and erythrocyte cholinesterases, hepatic and renal non-specific carboxylesterases were assayed. Serum biochemical markers of hepatic function were measured. Histologically stained sections of liver were examined by light microscopy. Fenitrothion, at doses between 2.5 and 10 mg/kg body wt, caused few observable deleterious effects to male rats except those effects on tissue esterases associated with organophosphorus esters. Only 8 of 36 animals receiving the 20.0 mg/kg dose died, all in the first week of treatment. A dose-dependent decrease in tissue esterase activity was observed which persisted throughout the entire treatment period. Periodic signs of overt toxicity were observed only in animals receiving 20 mg/kg/day. Tissue esterase activities returned to control levels within 1 or 2 weeks of stopping treatment. No significant treatment-related changes were observed by serum biochemistry or by light microscopy.

Animals↗
PubMed1978

The development of hepatic drug-metabolizing enzymes in perinatal guinea pigs: a biochemical and morphological study.

The development of four functionally diverse, hepatic enzymes (p-nitroanisole O-demethylase, aniline hydroxylase, carboxyleterase, and glucuronyltransferase (with alpha-naphthol as the aglycone acceptor)) was studied in perinatal Hartley guinea pigs from 8 days prepartum to 28 days postpartum. A good correlation was observed between the activities measured in resuspended Ca2+-aggregated microsomes and the quantities of hepatic smooth endoplasmic reticulum visible by electron microscopic examination at the different stages of development. The study demonstrated that, postnatally, the guinea pig developed competent enzymatic systems as rapidly as did other laboratory species but that, prenatally, these same enzyme(s) systems were much further advanced than those in other species.

Aniline Hydroxylase↗
PubMed1977

Acute fenitrothion poisoning.

A technician was accidentally exposed to the organophosphorus insecticide fenitrothion and subsequently treated with pralidoxime for the autonomic, somatic and psychiatric manifestations of intoxication. Although long-term therapy with pralidoxime is not recommended, this patient required and obtained symptomatic benefit from its prolonged use. Erythrocytic and plasma cholinesterase activities had been monitored prior to exposure and were monitored throughout treatment and following recovery. Continual monitoring of cholinesterase activities of individuals occupationally exposed to organophosphorus ester insecticides and early diagnosis are essential.

Adult↗
PubMed1977

Dependence of gel-filtered guinea pig hepatic microsomes on a soluble factor for maximum mono-oxygenase activities.

Guinea pig hepatic microsomes were prepared by gel filtration on Sepharose 2B. A second, peak containing protein and hemoproteins (Hp) markedly increased mono-oxygenase activities when added to the microsomes. Gel filtration of guinea pig microsomes prepared by differential centrifugation revealed possible dissociation during elution from the Sepharose column. Parallel experiments with rat liver were negative.

Aniline Hydroxylase↗
PubMed1976

Species differences in the reactivation of organophosphate-inhibited plasma esterases by diacetylmonoxime.

A study was conducted to assess whether the protection afforded to organophosphatepoisoned animals by diacetylmonoxime (DAM) was correlated with the reactivation of non-essential aliesterases (AliE). In vitro, the DAM-catalyzed reactivation of plasma AliE and cholinesterases (psi ChE) of rat, rabbit and guinea pig inhibited by 10-5 M diisopropylphosphorofluoridate (DFP) and O,O-dimethyl-2,2-dichlorovinyl phosphate (DDVP) was investigated. Marked reactivation of the rat plasma enzymes was achieved with 10mM DAM. Higher concentrations (30 mM) were necessary for the slow reactivation of rabbit and guinea pig plasma AliE. Reactivation of the psiChE of these species was comparatively slow. Reactivation of DDVP-inhibited esterases proceeded in all species at a more rapid rate than those inhibited by DFP. The dependence of psiChE reactivation upon concomitant more rapid reactivation of AliE by DAM was demonstrated using Sephadex fractionated AliE and psiChE but only a marked effect was observed with the rat, suggesting that the plasma AliE of this species is functionally different. The in vitro observations were confirmed by in vivo studies in rats and rabbits. DAM (50 or 150 mg/kg), administered to atropinized rats 15 min before a lethal dose of DFP, protected the animals. Few severe toxic signs were observed and reactivation of both plasma AliE and psiChE occurred. In contrast, DAM protected the rabbit against a lethal dose of DFP but only reactivation of the erythrocyte acetylcholinesterase was observed.

Animals↗
PubMed1976

Preparation of guinea pig hepatic microsomes: a comparison of three techniques.

Hepatic microsomal preparations by Ca2+-aggregation and gel filtration on Sepharose 2B were compared with the product obtained by differential centrifugation, using liver from adult male guinea pigs. The conventionally-prepared microsomes were translucent and rose-red in color. Those prepared by Ca2+-aggregation were a cream or light pink color whereas the gel-filtered microsomes were opalescent and white. The specific activities of microsomal p-nitroanisole O-demethylase, aniline hydroxylase and nonspecific carboxylase were highest in the Ca2+-aggregated microsomes, intermediate in the gel-filtered preparation and lowest in the conventional microsomes. Electron microscopy revealed vesicular preparations of similar appearance though the Ca2+-aggregated microsomes were larger and contained more aggregates of free ribosomes.

Aniline Hydroxylase↗