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At least 181 records · Page 10Linked to original sources

Exposure to industrial solvents and brain atrophy. A retrospective study of pneumoencephalographic findings among 37 patients with exposure to industrial solvents.

Pneumoencephalographic (PEG) findings of 37 patients referred to the Institute of Occupational Health, Helsinki, because of suspected chronic organic solvent intoxication showed changes suggesting brain atrophy in 64% of the patients. Slight asymmetric central and slight local cortical atrophy were the most common findings. There were no significant difference between those considered having heavy exposure and those with less significant exposure either in regards to PEG findings or other neurological findings. Thus, lack of dose-response relationship in this study suggests nonspecificity of the slight PEG findings and possibly also individual susceptibility to neurotoxic agents.

Atrophy↗

Studies on kidney function in subjects exposed to organic solvents. II. The effect of desmopressin in a concentration test and the effect of exposure to organic solvents on renal concentrating ability.

The renal concentrating ability was studied in 11 subjects by means of 14-16 hours of fluid deprivations, alone and in combination with the vasopressin analogue desmopressin. The effect of desmopressin without fluid deprivation on urinary osmolality was also studied. The combination of desmopressin and fluid deprivation was not superior to fluid deprivation alone for the production of concentrated urine. Desmopressin alone was inferior to the other two methods. No difference in renal concentrating ability could be demonstrated after 14 hours of fluid deprivation, when comparing 118 subjects exposed to various organic solvents with 48 controls.

Adult↗

Comparative genomic analysis of solvent extrusion pumps in Pseudomonas strains exhibiting different degrees of solvent tolerance.

Organic solvents are inherently toxic for microorganisms. Their effects depend not only on the nature of the compound, but also on the intrinsic tolerance of the bacterial species and strains. Three efflux pumps belonging to the RND (resistance-nodulation-cell division) family of multidrug extrusion pumps are the main factor involved in the high intrinsic tolerance to toluene of Pseudomonas putida DOT-T1E. We have analyzed the tolerance to toluene shocks [0.1% and 0.3% (v/v)] of a number of strains belonging to different species of the genus Pseudomonas upon growth in the absence and in the presence of sublethal concentrations of toluene. The strains can be grouped in three categories: (1) highly resistant strains, in which almost 100% of the cells precultured in the presence of sublethal concentrations of toluene withstood a 0.3% (v/v) toluene shock, (2) moderately resistant strains, in which only a fraction (10(-4)-1) of the cells withstood a 0.1% (v/v) toluene shock, but fewer than 1 in 10(7) cells survived a sudden 0.3% (v/v) toluene shock regardless of the growth conditions, and (3) sensitive strains, in which regardless of the growth conditions fewer than 10(-5) cells survived a 0.1% (v/v) toluene shock. We also studied the number and type of efflux pumps in different strains in comparison with the P. putida DOT-T1E strain.

Adaptation, Physiological↗

Toluene metabolism by the solvent-tolerant Pseudomonas putida DOT-T1 strain, and its role in solvent impermeabilization.

Pseudomonas putida DOT-T1E is a solvent-tolerant strain able to grow with toluene as the sole C-source. Tn5 mutagenesis was carried out and a mutant unable to use toluene as the sole C-source was isolated. DNA was sequenced upstream and downstream of the site where the Tn5 was inserted. Analysis of the DNA revealed 13 open reading frames (ORFs) homologous to the tod genes for the toluene dioxygenase pathway of P. putida F1, which are organized in two operons: todXFC1C2BADEGIH and todST. The Tn5 was inserted at the todH gene. The role of the todXFC1C2BADEGIH operon in toluene metabolism was further confirmed in a todC1 mutant (generated by insertional inactivation), which was unable to use toluene as the sole C-source. Primer extension analysis identified a single promoter upstream from the todX gene. The -10 and -35 regions of this promoter showed no significant homology to known promoters. Expression from the todX promoter occurred in response to toluene, ethylbenzene, styrene, xylenes and other aromatic hydrocarbons. Expression from the todS gene was constitutive. Sensitivity to toluene of the todH and todC1 mutants was similar to that of the wild-type strain. This suggests that toluene metabolism is not involved in toluene tolerance.

Base Sequence↗

Peptide synthesis catalyzed by organic solvent-stable protease from Pseudomonas aeruginosa PST-01 in monophasic aqueous-organic solvent systems.

The equilibrium yields of the peptide Cbz-Arg-Leu-NH2 synthesized from Cbz-Arg and Leu-NH2 using the PST-01 protease in the presence of organic solvents were investigated under various conditions. The equilibrium yields depended little on the concentration of the carboxyl component, but significantly on the concentration of the nucleophile. The optimum temperature and pH for a high equilibrium yield were 30 degrees C and greater than 5.0, respectively. Under optimum conditions the equilibrium yields were 71.6% and 87.7% in the presence of 50% (v/v) DMF and 60% (v/v) DMSO, respectively. Furthermore, the PST-01 protease also catalyzed the syntheses of the dipeptides Cbz-Lys-Leu-NH2, Cbz-Ala-Leu-NH2, Cbz-Ala-Phe-NH2, Cbz-Arg-Leu-NH2, and Cbz-Lys-Phe-NH2 with equilibrium yields of more than 60% in the presence of 50% (v/v) DMF and 50 mM sodium phosphate buffer (pH 7.0).

Journal Article↗

Elucidating the vibrational spectra of hydrogen-bonded aggregates in solution: electronic structure calculations with implicit solvent and first-principles molecular dynamics simulations with explicit solvent for 1-hexanol in n-hexane.

Fourier transform infrared spectroscopy is a popular method for the experimental investigation of hydrogen-bonded aggregates, but linking spectral information to microscopic information on aggregate size distribution and aggregate architecture is an arduous task. Static electronic structure calculations with an implicit solvent model, Car-Parrinello molecular dynamics (CPMD) using the Becke-Lee-Yang-Parr (BLYP) exchange and correlation energy functionals and classical molecular dynamics simulations for the all-atom version of the optimized parameters for liquid simulations (OPLS-AA) force field were carried out for an ensemble of 1-hexanol aggregates solvated in n-hexane. The initial configurations for these calculations were size-selected from a distribution of aggregates obtained from a large-scale Monte Carlo simulation. The vibrational spectra computed from the static electronic structure calculations for monomers and dimers and from the CPMD simulations for aggregates up to pentamers demonstrate the extent of the contribution of dangling or nondonating hydroxyl groups found in linear and branched aggregates to the "monomeric" peak. Furthermore, the computed spectra show that there is no simple relationship between peak shift and aggregate size nor architecture, but the effect of hydrogen-bond cooperativity is shown to differentiate polymer-like (cooperative) and dimer-like (noncooperative) hydrogen bonds in the vibrational spectrum. In contrast to the static electronic structure calculations and the CPMD simulations, the classical molecular dynamics simulations greatly underestimate the vibrational peak shift due to hydrogen bonding.

Journal Article↗

Use of solvent cavity area and number of packed solvent molecules around a solute in regard to hydrocarbon solubilities and hydrophobic interactions.

Two currently used methods of calculating the area of contact between a solute molecule and the solvent are examined and some important differences are pointed out. Some pitfalls and uncertainties in the application of the concept of molecular surface area to the quantitative estimation of unitary free energies of solution are discussed.

Journal Article↗

Inhalation toxicity of a smoke containing Solvent Yellow 33, Disperse Red 9 and Solvent Green 3 in laboratory animals.

The repeated-dose inhalation toxicity of a smoke containing a mixture of three dyes was tested in female mice, rats and guinea pigs. The green component dye (Solvent Green 3) was retained in the lungs. Particularly in the rats marked collections of alveolar macrophages were found. In the same species several other adverse findings were noted: these included adenocarcinomas of the breast in the high-dose group and a dose-related incidence of biliary hyperplasia. Fatty change was noted in the livers of the test-group mice. A large proportion of the high-dose guinea pigs died during the exposure period, for which reason exposure was stopped early in that group, otherwise the guinea pigs were little affected. However, all test groups of all species showed reductions in growth during the exposure period.

Animals↗