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T A Kilroe-Smith

Publications and source records attributed to T A Kilroe-Smith.

36 records · Page 2Linked to original sources
PubMed1985

Erythrocyte zinc protoporphyrin determination for screening for lead exposure.

Free erythrocyte protoporphyrin (FEP), erythrocyte zinc protoporphyrin (EZP) and blood lead concentrations were measured in 150 male subjects, 110 of whom were employed in industries where lead exposure was possible. Eighty-seven per cent of these 110 workers had blood lead levels above the maximum safe level of 40 micrograms/dl, which suggests that the factory control of lead toxicity is inadequate. The AVIV dedicated front-face fluorometer (AVIV instruments, New Jersey, USA), which measures EZP, was evaluated as a simple, rapid method of screening for lead accumulation. EZP concentrations agreed well with conventional estimations of FEP (r = 0,987, P less than 0,0001), and both correlated well with the blood lead concentration (r = 0,558, P less than 0,0001 for EZP; r = 0,633, P less than 0,0001 for FEP). The specificity of the EZP level as a screening test was found to be high (98%) and the sensitivity moderately good (83%). In view of the ease and speed of operation of this portable fluorometer, it should prove useful as an aid to the detection of early lead intoxication.

Environmental Exposure↗
PubMed1985

Plasma amino acids and tissue methionine levels in fruit bats (Rousettus aegyptiacus) with nitrous oxide-induced vitamin B12 deficiency.

The effect of methylcobalamin inactivation by the gas nitrous oxide on plasma amino acid and tissue methionine levels in fruit bats (Rousettus aegyptiacus) was examined. Animals exposed to N2O-oxygen (1:1, v/v) for 90 min daily received a fruit diet with or without methionine or betaine supplements. Exposure and diets were continued for up to 17 weeks or until neurological impairment and muscular weakness was established. All the groups exposed to N2O had significantly lower liver, brain and plasma methionine concentrations except the methionine-supplemented animals which showed significantly raised levels. Plasma homocysteine, which was absent in controls, was present in all the N2O-exposed groups. Betaine supplementation resulted in reduced accumulation of homocysteine in plasma. However, plasma and liver methionine levels were only slightly increased compared with animals on the basal diet, and brain methionine levels were the lowest of all the groups studied. These results support the hypothesis that reduced methionine synthesis is an important contributor to the development of neurological impairment in this species and suggest that dietary supplementation with the methionine precursor betaine cannot replace the loss of vitamin B12-dependent methionine synthesis.

Amino Acids↗
PubMed1979

The effects of sodium arsenate on the free amino acid levels in erythrocytes and plasma in rats.

The effects of arsenate on the levels of free amino acids in rat plasma and red blood cells have been investigated. The biggest changes occur in the branched-chain amino acids valine, isoleucine and leucine which are markedly decreased. The levels of several other amino-acids also change. The effects on the amino acids are not due to a change in the food intake caused by dosing with arsenate. This has been shown by comparing the results with those on fasting rats (40 h). Branched-chain amino acids in particular are markedly increased in plasma of fasting rats as opposed to a decrease in arsenate-treated rats.

Amino Acids↗
PubMed1977

The effect of manganese and ferric ions on the in vitro formation of dihydrodihydroxy metabolites of benzo(a)pyrene.

The effect of ferric and manganese ions on the in vitro metabolism of benzo(a)pyrene (BP) to dihydrodihydroxy (diol) metabolites by rat liver microsomal preparations was studied. Of the 3 diols separated by high-pressure liquid chromatography (HPLC) and called diols 1, 2 and 3 in order of elution, diol 1 was identified by its U.V. spectrum as the 9,10-diol; diols 2 and 3 have not yet been identified positively but are probably the 4,5- and 7,8-diols respectively. Higher concentrations of both metals altered the diol profile; 10 and 50 mumol Fe3+ per incubation caused the disappearance of diols 1 and 2 and an increase in diol 3; 10 mumol Mn2+ caused a significant decrease in diol 2 while 50 mumol reduced diol 2 to a negligible amount and inhibited the formation of diol 1; both concentrations caused a relative increase in diol 3. If the tentative identification of diol 3 as the 7,8-diol is correct, manganese and ferric ions could be significant in the metabolism of BP to the active metabolite, the 7,8-diol-9,10-epoxide.

Animals↗
PubMed1977

The effect of zinc and pH on the behaviour of delta-aminolevulinic acid dehydratase activity in baboons exposed to lead.

Four adult male baboons (Papio ursinus) were exposed to a cloud of lead oxide dust to induce changes in the status of delta-aminolevulinic acid dehydratase (ALAD). Enzyme activity fell rapidly to a steady state as blood lead levels rose above normal. Exogenous zinc was shown to activate the enzyme, and the antagonistic effect of zinc on in vivo and in vitro lead inhibition was demonstrated for baboons. In baboons not exposed to lead dust, ALAD showed an activity optimum at pH 7-1 which shifted to pH 6-8 with in vitro addition of lead. In baboons exposed to lead dust, with raised blood lead, activity optima were observed at pH 6-8 and 6-2, while the optimum at pH 7-1 was absent.

Animals↗
PubMed1976

Peritoneal transfer of thiamphenicol during peritoneal dialysis.

The pharmacokinetics of thiamphenicol (TAP) was studied in 17 functionally anephric patients during peritoneal dialysis. Eleven patients were given single intramuscular injections of TAP in doses of 10 to 20 mg/kg of body weight. After this, serial blood samples and outflow dialysate collections were assayed for TAP by gas chromatography. The mean overall elimination rate constant was 0.036 +/- 0.007/h, the serum half time was 8.4 h, and the apparent volume of distribution was 71.0% (+/-14.39%) of the body weight. These parameters were not significantly different from those determined in anephric patients not on dialysis. The mean recovery of the administered TAP doses in the pooled outflow dialysate was 7.7% (+/-2.76%) over 22 h. In six other patients TAP was added to the inflow dialysate in concentrations of 10 to 20 mg/liter for 22 h. Throughout the dialysis periods, serum TAP levels did not rise above 4 mug/ml in transfer of TAP.

Adult↗
PubMed1976

The in vitro effect of zinc on the inhibition of human delta-aminolevulinic acid dehydratase by lead.

The antagonistic effect of zinc on inhibibition of human aminolevulinic acid dehydratase (ALAD) by lead was examined in vitro. The phenomenon was studied at pH 6.5-7.5 . Zinc and lead were added at concentrations ranging from physiological levels to levels far in excess of those expected in heavy industrial exposure. ALAD activity of normal blood assayed in the presence of zinc was unaffected by exogenous lead if the added zinc concentration was above 0.53 mmol/l blood, or double the normal endogenous level, and was of the order found in heavy industrial exposure to zinc. In this case, ALAD assay values were appreciably raised and might have fallen into the normal range in spite of a dangerous total blood lead of over 0.0048 mmol/l. When zinc was added in vitro to blood from a worker with a blood lead level of 0.0043 mmol/l the ALAD values obtained were also raised and did not reflect the dangerous level of lead in the patient.

Environmental Exposure↗
PubMed1975

Linear working graphs in blood lead determinations with the Beckman flameless atomic absorption cuvet.

Working graphs are generally nonlinear when the longitudinal flameless atomic absorption cuvet is used. Such nonlinear curves make it difficult to determine the amount of lead in blood by the method of additions, because of inaccuracies in extrapolating the graph to zero absorbance. This paper describes a method for obtaining linear graphs by making use of opacity (the reciprocal of transmittance, or antilog of the absorbance) instead of absorbance. Because no deuterium arc background corrector is available for the Beckman Model 444, background was correlated by reading the opacity at a nonabsorbing line, 287.3 nm, and subtracting the opacities. A separate reagent-blank correction for lead must also be made.

Adult↗