Cumulative risk assessment of the intake of organophosphorus and carbamate pesticides in the Danish diet.

The aim of the study is to evaluate the potential cumulative effects of organophosphorus and carbamate pesticides that act through a common mechanism of toxicity, and to assess the long- and short-term risks for the Danish population. The intake estimates are based on dietary intake data collected in the Danish nation-wide food consumption survey in 1995. The pesticide data are based on the Danish pesticide residue-monitoring programme from 1996-2001. The amount of 35 organophosphorus pesticides and carbamates were included in the cumulative risk assessment. Processing factors, such as reduction of pesticide levels by rinsing and peeling, were applied in the exposure assessment. The "Toxicity Equivalence Factor" (TEF) approach was used to normalise the toxicity of the different organophosphorus and carbamate pesticides. Cumulative chronic exposure of organophosphorus and carbamates pesticides via fruit, vegetables and cereals is for adults 0.8-2% of the Acceptable Daily Intake (ADI) in chlorpyrifos equivalents, and 0.03-11% of the ADI in methamidophos equivalents; and for children 2-5% of the ADI in the chlorpyrifos equivalents, and 0.07-27% of the ADI in methamidophos equivalents. Neither Acute Reference Dose (ARfD) nor ADI was exceeded for any of the compounds studied. The results indicate that the Danish population is neither exposed to any cumulative chronic risk, nor at risk of acute exposure, from consumption of organophosphorus and carbamate pesticides from fruit, vegetables and cereals.

1-(1,2,5-Thiadiazol-4-yl)-4-azatricyclo[2.2.1.0(2,6)]heptanes as new potent muscarinic M1 agonists: structure-activity relationship for 3-aryl-2-propyn-1-yloxy and 3-aryl-2-propyn-1-ylthio derivatives.

Two new series of 1-(1,2,5-thiadiazol-4-yl)-4-azatricyclo[2.2.1.0(2, 6)]heptanes were synthesized and evaluated for their in vitro activity in cell lines transfected with either the human M1 or M2 receptor. 3-Phenyl-2-propyn-1-yloxy and -1-ylthio analogues substituted with halogen in the meta position showed high functional potency, efficacy, and selectivity toward the M1 receptor subtype. A quite unique functional M1 receptor selectivity was observed for compounds 8b, 8d, 8f, 9b, 9d, and 9f. Bioavailability studies in rats indicated an oral bioavailability of about 20-30%, with the N-oxide as the only detected metabolite.

Individual variations of pH, buffer capacity, and concentrations of calcium and phosphate in unstimulated whole saliva.

In order to evaluate the risk of development of dental caries and/or of formation of dental calculus, salivary variables have often been used, but not with particular success. A reason for the apparent lack of association could be that the individual temporal variation of a characteristic was so substantial relative to the overall variation that it is not possible to characterize an individual by a single salivary measurement. The aim here was to examine the individual variation of pH, buffer capacity, and concentrations of calcium and phosphate and to compare it with the overall variation of the characteristics in order to shed light on the above problem. Eight weekly samples of up to 4 ml of unstimulated whole saliva were collected from 11 dental students before tooth brushing on their arrival at 8 a.m. in the dental school. Calcium was determined by atomic absorption spectroscopy, phosphate colorimetrically, and pH electrometrically. The buffer capacity was assessed by titration of the saliva sample from the pH initially observed to pH 3. It was found that within each individual the concentration of calcium and of phosphate, pH, the hydroxyapatite ion product and the buffer capacity varied considerably over the 7 weeks. The individual range frequently covered more than a third of the total range. Further, within each of the variables, single individuals could be found whose samples covered 60% or more of the overall range, whilst others covered less than 10% of the range. It was therefore concluded that, although collected at the same time of the day, pH, buffer capacity and concentrations of calcium and phosphate in unstimulated whole saliva in the single individual vary so much that characterization of individuals and of their saliva based on a single salivary analysis is unreliable and hazardous.

Absorption and disposition of N-(1, 1-dimethylethyl)-N'-[2-(4-pyridinyl)-4-pyrimidinyl]urea in rats and dogs.

N-(1, 1-Dimethylethyl)-N'-[2-(4-pyridinyl)-4-pyrimidinyl]urea, Win 40, 882, was eliminated from the blood stream of dogs by two apparent first-order processes with alpha- and beta-phase half-lives of 0.2 hr and 1.4 hr, respectively. Radioactivity of the administered dose was excreted by rats in the feces and via the kidneys; about 40-45% of the dose was recovered in the feces, with the remainder in the urine, over a six day period. One of the terminal methyl groups of the tert-butyl moiety of Win 40,882 is sequentially oxidized by the rat to the alcohol, aldehyde and carboxylic acid. In addition, some of the aldehyde was further metabolized to generate two different monohydroxylated aldehydic metabolites; these hydroxyaldehydes accounted for less than 10% of the dose administered. An unusual metabolic pattern was noted in the excretion of Win 40,882. Over 30% of the urinary metabolites contained the carboxaldehyde function; only8% of the urinary radioactivity was represented by the further oxidation of the aldehyde group to generate the carboxylic acid.

Radioimmunoassay for danazol in human and monkey plasma.

A sensitive method is described for the radioimmunoassay of danazol in monkey and human plasma. Antiserum was developed in rabbits, and a second antibody was used to separate bound from free danazol. The radioimmunoassay was specific for danazol, and the limit of detection ranged from 1.4 to 2.8 ng/ml. Exogeneous danazol could be quantitated accurately in both monkey and human plasma. The radioimmunoassay results agreed with values obtained by inverse isotope dilution after intravenous administration of 14C-danazol to monkeys. The assay was used successfully to measure danazol in plasma from human volunteers receiving 200 mg of danazol.