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The levels of some heavy metals in spent engine oils and in the fingernails of auto-mechanics were studied. Engine oils and fingernails were collected from auto-mechanics who had practiced between ≤ 5 years, ≤ 10 years and ≤ 15 years in 3 auto-mechanic workshop clusters. Pb, Ni, V, Cd, and As levels were determined using Atomic Absorption Spectrophotometer. The mean levels of Pb, Ni, V and Cd in spent engine oils were 14.31, 2.25, 0.38 and 2.07 ppm respectively, and these far exceeded their permissible exposure limits. The mean levels of heavy metals in the fingernails of auto-mechanics who had practiced for ≤ 5 years, ≤ 10 years and ≤ 15 years were all considerably below their pathological thresholds. Thus, auto-mechanics in the study area are exposed to unsafe levels of Pb, Ni, V, and Cd, but no immediate threat of their toxicities in the study population exist. However, a progressive bioaccumulation of the heavy metals was observed with increase in years of practice.

Performance evaluation of a formulated infant food on some biological indices in Wistar rats was investigated. For rats fed separately with normal rat feed, formulated infant food and proprietary food, serum total protein and albumin were determined by colorimetric method, red blood cell (RBC) and differential white blood cell (WBC) counts were determined with a haemocytometer, packed cell volume (PCV) was by micro-haematocrit, haemoglobin (HGB) was determined using cyanomethaemoglobin method while mean cell volume (MCV) and mean cell haemoglobin (MCH) were calculated. The results obtained showed that, for Wistar rats fed with normal rat feed, the baseline values prior to the commencement of feeding trial for serum total protein, albumin, body weight, PCV, WBC, platelet count (PLT), RBC, HGB, lymphocyte count (LYM), MCH, MCV, neutrophil (NEU), and eosinophil (EOS) were 82.9 g/dL, 44.75 g/dL, 142.80g, 41.14%, 7.60×103μL−1, 404.85×103μL−1, 5.68×106μL−1, 10.80 g/dL, 50.28 %, 18.42 pg, 59.28 fL, 45.57 %, and 2.57 % respectively. After the feeding trial, the serum total protein, albumin, body weight, PCV, WBC, PLT, RBC, HGB, LYM, MCH, MCV, NEU, and EOS in Wistar rats fed with the formulated infant food (the experimental group) were 79.6 g/dL, 50.65 g/dL, 169.18g, 40.14%, 5.77 ×103μL−1, 309.85 ×103μL−1, 6.85×106μL−1, 12.45 g/dL, 52.85 %, 18.24 pg, 58.64 fL, 42.00 %, and 2.14% respectively and these were in most cases, either greater or comparable with their corresponding mean values of 69.1 g/dL, 44.40 g/dL, 177.97 g, 30.24%, 4.18×103μL−1, 188.14×103μL−1, 5.29×106μL−1, 10.74 g/dL, 53.14 %, 20.37 pg, 57.61 fL, 38.85 %, and 4.57 % respectively in Wistar rats fed with the proprietary infant formula (the control group). This shows that the potential infant food has a more positive effect on most of the biological indices assessed than the proprietary infant food or a comparable effect at the least.

The effect in rabbits of the sarinase levels of liver and plasma, and of cholinesterase levels of plasma on survival after repeated intraperitoneal or subcutaneous doses of sarin has been investigated. When the intraperitoneal route was used a significant correlation was found between liver sarinase and survival. Survival after subcutaneous injection was not affected by the liver sarinase. No correlation was found between plasma sarinase or plasma cholinesterase and survival for either the intraperitoneally or subcutaneously injected rabbits.

The enzymes which hydrolyze isopropyl methylphosphonofluoridate (sarin) and ethyl N, N-dimethylphosphoramidocyanidate (tabun) have been studied. Michaelis–Menten constants and activation energies have been estimated and enzyme stability has been studied. The distribution of the enzymes in mammalian tissues has been examined. It is concluded that from each source the same enzyme is responsible for the hydrolysis of sarin and tabun but that this enzyme shows variations from source to source. That there are mixtures of very similar enzymes, having a composition in amounts characteristic of the source, is also considered possible.

The cells of the liver and kidneys from three species known to be comparatively susceptible to sarin (rabbit, guinea pig, and monkey) and two species known to be less susceptible (rat and mouse) have been fractionated into their cell constituents (nuclei, mitochondria, microsomes, and non-particulate fraction). Each fraction has been tested for sarinase activity. The non-particulate fraction had the highest activity, the microsomes the second highest, the mitochondria the third highest, and the nuclei the lowest. The significance of the differences found in the distribution of sarinase activity in the cell fractions is discussed.Monkey cell fractions were also tested with ethyl N,N-dimethylphosphoramidocyanidate (tabun) as the substrate. The results were similar to those obtained with sarin, suggesting that the same enzyme was responsible for the hydrolysis of both substrates.

The cells of the liver and kidneys from three species known to be comparatively susceptible to sarin (rabbit, guinea pig, and monkey) and two species known to be less susceptible (rat and mouse) have been fractionated into their cell constituents (nuclei, mitochondria, microsomes, and non-particulate fraction). Each fraction has been tested for sarinase activity. The non-particulate fraction had the highest activity, the microsomes the second highest, the mitochondria the third highest, and the nuclei the lowest. The significance of the differences found in the distribution of sarinase activity in the cell fractions is discussed.Monkey cell fractions were also tested with ethyl N,N-dimethylphosphoramidocyanidate (tabun) as the substrate. The results were similar to those obtained with sarin, suggesting that the same enzyme was responsible for the hydrolysis of both substrates.

The enzymes which hydrolyze isopropyl methylphosphonofluoridate (sarin) and ethyl N, N-dimethylphosphoramidocyanidate (tabun) have been studied. Michaelis–Menten constants and activation energies have been estimated and enzyme stability has been studied. The distribution of the enzymes in mammalian tissues has been examined. It is concluded that from each source the same enzyme is responsible for the hydrolysis of sarin and tabun but that this enzyme shows variations from source to source. That there are mixtures of very similar enzymes, having a composition in amounts characteristic of the source, is also considered possible.

The effect in rabbits of the sarinase levels of liver and plasma, and of cholinesterase levels of plasma on survival after repeated intraperitoneal or subcutaneous doses of sarin has been investigated. When the intraperitoneal route was used a significant correlation was found between liver sarinase and survival. Survival after subcutaneous injection was not affected by the liver sarinase. No correlation was found between plasma sarinase or plasma cholinesterase and survival for either the intraperitoneally or subcutaneously injected rabbits.