New model for dwelling dose calculation using Monte Carlo integration.

A new methodology and computer model using Monte Carlo simulation for indoor dose calculation are developed. A room model of six rectangular slabs of finite thickness with door or window in each slab was used. Point-kernel photon transport model with self-absorption correction was applied for dose calculations. New software was designed and programmed using Pascal programming language, which was evaluated for standard room design. The calculated dose due to natural radionuclides in the concert walls has differences from the average model results of 0.21% for (238)U, 12.3% for (232)Th and 13.9% for (40)K; and the variability of specific dose rate with changing position density and composition of walls was studied. The new model has more flexibility for real dose calculation of any room structure and tailing, which is not given in the published models.

Control of Musca domestica third instar larvae by the latex of Calotropis procera (Family: Asclepiadaceae).

Calotropis procera (Family: Asclepiadaceae) is known to contain alkaloids, steroids and resinous substance. Different concentrations of its latex were topically applied to the 3rd stage larvae of Musca domestica. A dose of 3 ul (5% of the latex) killed and partially digested the larvae in three hours. The effect of this latex is most probably enzymatic in nature. No doubt, the shift to plant extracts in controlling insect-vectors or pests in general, pave the way to a health environment.

Studies on the present status of insecticides resistance on mosquitoes using the diagnostic dosages in El-Fayium Governorate, a spot area of malaria in Egypt.

Insecticides susceptibility tests were conducted using the World Health Organization diagnostic doses on the adult and larvae of Anopheles pharoensis and Culex pipiens mosquitoes from Fayium Governorate in Egypt. Insecticides used were malathion, fenitrothion, temephos, diazinon, bromophos and fenthion from organophosphorous group and deltamethrin, permethrin and cypermethrin from synthetic pyrethroid group while propoxur was from carbamate group. Larvae of A. pharoensis were resistant to fenitrothion and susceptible to other insecticides used, while the adults were susceptible to malathion, deltamethrin, fenitrothion and premethrin. Larvae of C. pipiens were resistant to temephos, fenitrothion, bromophos and fenthion and susceptible to malathion, permethrin and diazinon, while the adults were resistant to fenitrothion, permethrin and propoxur and susceptible to deltamethrin, cypermethrin and malathion. These results are important for the success of the control programmes and monitoring the susceptibility status of vectors.

Insecticidal properties of citrus oils against Culex pipiens and Musca domestica.

Peel oils of lemon, grapefruit and navel orange were tested for insecticidal activities against larvae and adults of Culex pipiens and Musca domestica. Lemon peel oil was the most effective against larvae and adults of C. pipiens. Grapefruit peel oil was more toxic to adults of M. domestica while lemon oil, was more toxic Musca larvae. On the other hand, the orange peel oil was the least effective against larvae and adults of both species. The toxicity of oils applied to larval stages was extended to pupal and adult stages. C. pipiens adults appeared with paralyzed legs, while M domestica adults appeared normal. The weights of pupae treated as larvae were generally less than that of the control. All oils produced deleterious effects on fecundity of survivors of sublethal doses. The effect was obviously recorded in treated adults. Treatment of Culex & Musca with oils caused serious latent effect.

Effect of ivermectin on survival and fecundity of Culex pipiens the vector of Wuchereria bancrofti in Egypt.

The effect of two different doses of ivermectin on the survival and fecundity of Culex pipiens was evaluated. Female mosquitoes (50 in each group), same age and generation, were fed once on blood from ivermectin-treated rabbits. Comparative treatments consisted of two different doses of ivermectin (0.1 mg or 0.4 mg/kg of body weight), and mosquito groups were fed on the rabbits at 3 days and 10 days post-treatment respectively. Mosquitoes were maintained with 10% sucrose solution, at 25 degrees C and 70% relative humidity. Observations were made at 7, 10, 15, 20, 25, and 30 days post-feeding. Mosquitoes fed on rabbits treated with the small dose at three days post-injection showed reduced survival of 94%, 62%, 44%, 8% and 0%, while the 0.4 while the 0.4 mg/kg of body weight (bw) dose reduced survival to 88%, 60%, 6% and 0%. Survival of the control groups were 100%, 90%, 88%, 68% and 52% respectively. Survival of adult females fed at the lower dose, 10 days post injection were reduced to 92%, 90%, 84% 60% and 44%; while the higher dose reduced survival to 86%, 58%, 34% 22% and 0%. Survival of control groups were 96%, 92%, 84%, 78% and 72% respectively. Fecundity resulting from blood meals at 3 and 10 days post injection were 61% and 85% for the lower dose, and 0% and 42% for the higher dose respectively. Hatching of eggs was 82% and 88% for the 0.1 mg/kg bw dose, and no hatching was observed at the higher dose. Larval survival rates resulting from blood meals taken 3 days and 10 days post-injection of the lower dose were 24% and 25% respectively. However, no larvae survived from the high dose groups. Larval survival rates in control groups were 42% and 40%, respectively. These results provide new information about the effect of ivermectin on the vector of lymphatic filariasis, and add a new dimension to the use of ivermectin in filariasis control.

MR of primary extraosseous Ewing sarcoma.

We present MR imaging findings of a 15-year-old girl with a history of chronic back pain, proved by biopsy to be caused by primary extraosseous Ewing sarcoma, extending into the spinal epidural space. We also demonstrate the involvement of the adjacent structures and encroachment on the intervertebral foramina.

KO2 chemical transformation/mass spectrometry detection of covalent damage to the DNA of cultured human lymphocytes exposed to benzo[a]pyrene.

Cultured human lymphocytes were exposed to benzo[a]pyrene (B[a]P), and diol epoxide-type DNA adducts arising from this chemical were detected by a method consisting of the following sequence of steps: (1) isolate the DNA; (2) subject the DNA to mild acid hydrolysis to release the polyaromatic moiety as a tetrahydrotetrol; (3) add an internal standard; (4) oxidize the tetrahydrotetrol with potassium superoxide to pyrene-2,3-dicarboxylic acid; (5) derivatize the latter with pentafluorobenzyl bromide; (6) purify the diester product on a silica cartridge; and (7) detect this product by gas chromatography electron capture negative ion mass spectrometry. From the dose (1 microgram/mL) of B[a]P applied, five adducts in 10(7) normal nucleotides were found. Largely because steps 2-5 of the method take place sequentially in a single vial, the procedure is convenient and affords precise results. To demonstrate the potential of the method to detect KO2-susceptible polyaromatic hydrocarbon DNA adducts in general, including unknowns, it was also applied to picomole and femtomole amounts of a standard of chrysene-1,4-quinone using scanning and selected ion monitoring conditions, respectively, in the MS. Since standard products can be detected with selected ion monitoring at levels 10(4) below those encountered here (prior work), it should be possible in the future to extend the method to samples containing smaller amounts of such adducts.

Preparation of electrophoric derivatives of N7-(2-hydroxyethyl)guanine, an ethylene oxide DNA adduct.

Ethylene oxide, a potential human carcinogen, mainly damages DNA by reacting at guanine sites to form N7-(2-hydroxyethyl)guanine. In order to determine this DNA adduct with high sensitivity by gas chromatography, we have prepared, for comparison purposes, four electrophoric derivatives. The two that are most promising to date are bis- and tris-pentafluorobenzyl products prepared by first chemically transforming the N7-(2-hydroxyethyl)guanine to a corresponding xanthine, and then reacting the latter with pentafluorobenzyl bromide. These two derivatives are obtained in good yields and give molar responses of 0.6 and 0.5, respectively, relative to that of lindane by gas chromatography with electron-capture detection.

Novel synthesis of 2-fluoroestradiol from 19-nortestosterone: biomimetic oxidative defluorination to 2-hydroxyestradiol.

A new, short synthetic route to 2-fluoroestradiol from 19-nortestosterone is described which gives the target compound in an approximately 25% overall yield. Oxidative defluorination of 2-fluoroestradiol to 2-hydroxyestradiol via treatment with Frémy's salt/iodide ion is reported. This process is regarded as biomimetic with respect to cytochrome P-450-dependent oxidative defluorination.

Repetitive hit-and-run fluoroimmunoassay for T-2 toxin.

A monoclonal antibody for T-2 toxin is converted to a Fab'-fluorescein derivative. The latter is specifically complexed onto a T-2 agarose gel. Fifteen successive doses of T-2 ranging from 1 to 50 ng are then repetitively and linearly detected using a column packed with a small volume (0.2 ml) of this gel without recharging with Fab'-fluorescein. For these assays the effluent from the column is monitored with a spectrofluorometer.

Tresyl activation of a hydroxyalkyl ligand for coupling to a hydrazide gel: stable immobilization of T-2 toxin for affinity purification of T-2 antibody.

A stable T-2 hydrazide gel is prepared by activating T-2 toxin with tresyl chloride followed by coupling to agarose-adipic acid hydrazide. Utilized as an affinity chromatography column, this T-2 hydrazide gel purifies a monoclonal antibody for T-2 in high yield directly from ascites fluid. Specific antibody trapped on the column is eluted either with excess T-2 or at pH 11.6. Much less successful are two other T-2 affinity columns that were prepared and evaluated: T-2 bovine serum albumin Affi-Gel 15 and T-2 hexylamine Sepharose.