Cytogenetic activity of chemical compounds in adrenalectomized animals

Pyrimethamine, sodium salicylate or ethanol were administered to adrenalectomized rats 3 and 21 days after the operation. It is shown that cytogenetic effect in the operated rats is less pronounced, particularly 3 weeks after the operation. Adrenaline (0.2 mg/kg) increases the effect of chemicals on the chromosome apparatus, while hydrocortisone (50 mg/kg) and corticotropin (10 U/kg) decrease it.     

Cytogenetic activity of the pesticides cyclophos and alvison, their components and metabolites

Two new pesticide preparations of cyclophos and alvison, a number of their components, two alvison metabolites have been studied to reveal their cytogenetic activity. According to the investigation in vivo the mutagenic effect of cyclophos manifests itself only with toxic doses. Professional contacts with the pesticide don't induce chromosome mutation in human peripheral lymphocytes. The alvison preparations generate chromosome mutations in somatic cells of people and animals. The components and metabolites of alvison have shown no visible genetic activity during in vivo and in vitro experiments.     

Analytical method validation for the evaluation of cutaneous occupational exposure to different chemical classes of pesticides

In occupational exposure to pesticides, validated methodologies are available only in regards to homogeneous chemical classes of substances and the inhaling exposure, neglecting the cutaneous one that, especially in agriculture, represents an important route of absorption. An analytical methodology for the simultaneous quantification of different chemical classes of pesticides by using pads as environmental matrix and GC-MS/SIM as detection method was developed and validated. The extraction step of analytes from pads was optimized by comparing analytes recovery percentages obtained with different extraction solvents. High recoveries were obtained with ether and, above all, with acetonitrile. Validation experiments following the Food and Drug Administration Guidelines were carried out.     

The stemline chromosomes of three cell lines representing different vertebrate classes

The chromosomes of the stemlines were analyzed in three cell lines stored in the Cell Bank of the South Jersey Medical Research Foundation, Camden, N. J. The cell lines were of marsupial, amphibian and teleostean origin, and 10 to 25 complete chromosome analyses in each of them formed the basis for idiograms. In the marsupial and the frog, comparison could be made with the normal karyotype of the species.Dedicated to Professor J. Seiler on the occasion of his 80th birthday.     

A comparative analysis of mutagenic and SOS-induced activity in three classes of chemical compounds

Mutagenic and SOS-inducing potential of 23 derivatives of fluorenone, phenanthrenequinone and biphenyl have been studied in tester strains of Salmonella typhimurium and in Escherichia coli strain PQ 37. 14 of these compounds revert the mutation hisD3052 (much less than -1 much greater than type), but none of them induce mutations in the strain TA 1535. Maximal mutagenic activity has been shown in strain TA 1538 for amide of 2,7-dinitrofluorenone-4-carbonic acid (580 revertants per nmol), 2,7-dinitrophenanthrenequinone (308 revertants per nmol), 2,4,7-trinitrophenanthrenequinone (306 revertants per nmol) and 2',4,4'-trinitrobiphenyl-2-carbonic acid (251 revertants per nmol). In plasmid-containing strain TA 98 the mutagenic potential of the compounds tested is lower than in the TA 1538 strain. It has been suggested that mutagenic activity of these compounds can be attributed to their acceptor properties, namely, the ability to form charge transfer complexes with DNA. SOS-inducing activity has been shown for 5 compounds, also positive in mutation induction. Mutagenic and SOS-inducing activities positively correlate in fluorenone derivatives. Among phenanthrenequinone derivatives, compounds with high mutagenic activity only can induce SOS response. None of the biphenyls tested induce SOS functions. The compounds giving the positive result in the SOS-chromotest have rigid co-planar structure.     

The investigation of structure–activity relationship of polyamine-targeted synthetic compounds from different chemical groups

Amino Acids - The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation...     

Cytogenetic effects of pesticides. IV. Cytogenetic effects of the insecticides Gardona and Dursban.

The cytogenetic effects of the insecticides Gardona and Dursban were investigated. The toxicity and ability of both insecticides to induce chromosome aberrations and sister-chromatid exchange in vitro was tested in a primary culture of mouse spleen cells, in order to assess the potential mutagenicity of both insecticides. The concentrations 10(-7)-10(-3) M were used for testing the toxic effects of the insecticides. Both Gardona and Dursban were toxic to spleen cell cultures and the percentage of viable cells decreased as the concentration of the insecticide was increased. It reached 76.8% and 77.8% of control after treatment with the highest concentration tested (10(-3) M) of Gardona and Dursban respectively. Gardona at 0.25, 0.50, 1.0 and 2.0 micrograms/ml, and Dursban at 0.50, 1.0, 2.0 and 4.0 micrograms/ml were tested for the induction of chromosome aberrations and sister-chromatid exchanges. All of the tested concentrations of both insecticides induced a high percentage of metaphases with chromosomal aberrations in cultured mouse spleen cells after 4-h treatment. The frequency of SCEs/cell increased with increasing concentration of the insecticides. It reached 11.92 +/- 0.14/cell and 13.40 +/- 0.20/cell after treatment with Gardona (2 micrograms/ml) and Dursban (4 micrograms/ml), respectively, compared with 8.2 +/- 0.19/cell and 7.6 +/- 0.15/cell in the solvent control. The presented results indicate that both Gardona and Dursban in the tested concentrations are mutagenic in mouse spleen cell cultures.     

Odorants of different chemical classes interact with distinct odorant binding protein subtypes.

The ligand profile for three odorant binding proteins (OBPs) of the rat have been determined using a large number of odorous compounds from different chemical classes. To evaluate the binding spectra of distinct subtypes, all OBPs were produces in Escherichia coli as recombinant His-tagged fusion proteins. The individual binding properties of each OBP subtype were analysed using a large array of organic compounds, representing derivatives of aliphatic and aromatic compounds, as well as terpenes, pyrazines and thiazoles, in a competitive spectroscopic binding assay with various fluorescence chromophores as the specific interacting partner for the OBPs. Most of the compounds were identified to interact only with one OBP subtype. But interestingly, a small change, for example in the 2-methyl or 2-ethoxy side chain in the pyrazine and thiazole derivatives to a 2-isobutyl group, caused overlapping binding affinities to rat-OBP1 and rat-OBP3. However, the data strongly support the notion that each OBP subtype displays a characteristic ligand binding profile and interacts with a different subset of exogenous organic compounds in a micromolar range.     

Methods of determining the mutagenic activity of chemical compounds]

The paper deals with methods for determining the mutagenic activity of chemical compounds. Bacteria, cell culture and host-mediated assay were used for that purpose.     

Effect of chemical compounds on phospholipase A2 activity]

A simple and convenient method of simultaneous determinations of effects of any set of chemical compounds on enzymatic hydrolysis of phospholipids by using the method of diffusion phospholipase A2 in a lecithin-agarose gel.     

Complexes of porcine odorant binding protein with odorant molecules belonging to different chemical classes

Porcine odorant binding protein (pOBP) is a monomer of 157 amino acid residues, purified in abundance from pig nasal mucosa. In contrast to the observation on lipocalins as retinol binding protein (RBP), major urinary protein (MUP) or bovine odorant binding protein (bOBP), no naturally occurring ligand was found in the beta-barrel cavity of pOBP. Porcine OBP was therefore chosen as a simple model for structure/function studies with odorant molecules. In competition experiments with tritiated pyrazine, the affinity of pOBP towards several odorant molecules belonging to different chemical classes has been found to be of the micromolar order, with a 1:1 stoichiometry. The X-ray structures of pOBP complexed to these molecules were determined at resolution between 2.15 and 1.4 A. As expected, the electron density of the odorant molecules was observed into the hydrophobic beta-barrel of the lipocalin. Inside this cavity, very few specific interactions were established between the odorant molecule and the amino acid side-chains, which did not undergo significant conformational change. The high B-factors observed for the odorant molecules as well as the existence of alternative conformations reveal a non-specific mode of binding of the odorant molecules in the cavity.     

Cytogenetic study of workers exposed to chromium compounds

The frequency of sister chromatid exchanges (SCEs), high SCE frequency cells (HFCs), and genetic polymorphism of genotypes glutathione S-transferase (GST) M1 and T1 were analyzed in peripheral lymphocytes of 35 workers occupationally exposed to chromium (Cr) and 35 matched control group. Results showed that workers exposed to Cr showed 6.07 SCE/cell, as compared to 4.76 SCE/cell for the control group (p<0.01). Smokers showed a statistically significant higher frequency of SCE than non-smokers in both groups. The work duration of Cr workers was an important factor. Workers exposed for more than 5 years showed a significantly higher level of SCEs (p<0.05). Workers exposed to Cr for 5 or more years had higher HFC rates (51.4%) than those exposed for less than 5 years (22.9%), with an odds ratio of 4.5 times than those exposed for less than 5 years. In HFC analysis, Cr workers who smoked showed a higher level of HFC (60%) than the control group (5.7%) and also had a higher odds ratio (60.4) compared with the control group. Among non-smokers, the odds ratio was 9.0. Another objective of this study is to investigate the relationship between SCE and genetic polymorphisms of GST M1 and T1 in Cr workers. The results showed that the incidence of GSTM1 null genotype was 60% in the control group and 77.1% in Cr workers, and percentages of GSTT1 deletion were 42.9% and 62.9% in control and exposed individuals, respectively. There was a slightly increased frequency of SCE among Cr workers with GSTM1 null genotype as opposed to non-null genotype individuals. A similar result was seen among the control group; however, there were no statistically significant differences. In conclusion, the current study found the positive induction of SCE in workers who smoked or/and were exposed to Cr. However, different GST genotypes did not influence the level of cytogenetic damage between groups. Despite slight variation in numbers, they all appear to be not different.     

The mechanisms of the action of radioprotectors of different chemical classes in the intestinal syndrome

Some thiazole, triazole, thiadiazine, and heterylalkane derivatives increased the lifespan of gamma-irradiated (9-14 Gy) mice up to 6-22 days (as opposed to 4.1 days in the irradiated control). The efficacy of chemical agents within the dose range mentioned above was mainly associated with protecting intestinal epithelium stem cells the number of which was 4-9 times as large as that of nontreated animals. There was a moderate (40-50%) decrease in oxygen consumption under the effect of the most active radioprotectors.     

Comparative evaluation of the functional activity of different immunoglobulin classes in cholera]

The immunological activity of specific immunoglobulins in different forms of cholera infection was studied with the use of the indirect immunofluorescent method. The forms of cholera infection were shown to be related to the physico-chemical spectrum of antibodies: patients with the pronounced clinical symptoms of cholera produced serum IgM, including antigen -- antibody complex, more actively and in a greater amount; patients with faintly pronounced and asymptomatic infection produce highly active IgG. The competitive action of immunoglobulins of different classes in their simultaneous reaction with O antigen of Vibrio cholerae is shown. The mechanism of the competitive action of different immunoglobulin classes is supposed to play some role in the process of the sanation (with highly active IgM) or detoxication (with highly active IgG) of the organism.     

Local synchronized activity of neurons of different classes in cat primary visual cortex

The goal of the present study was to investigate the local synchronized neuronal activity in the cat visual cortex and the role of different classes of neurons in neural synchrony. Four classes of neurons were identified on the basis of electrophysiological properties of extracellularly recorded cells: RS, FS, IB, and FRB. It was revealed that neurons with short spikes and FRB type of activity were first engaged in synchronization. The model study revealed that neurons with the short action potential had more stable synchronized activity.     

Cytogenetic activity of various organophosphorus insecticides

The action of certain insecticides belonging to the group of organophosphorous compounds (chlorophos, metaphos, etaphos, phosphamid, phosalone, carbophos, selecron) has been studied by the test of chromosome aberrations in Crepis capillaris cells. It is shown that these insecticides possess mutagenic activity in all phases of the cell cycle and are mutagens of the undelayed action.