Search results for "Solvents"
showing 10 items of 291 documents
Lymphocyte subpopulations in solvent-exposed workers.
1986
To estimate the cellular immune response of workers highly exposed to mixtures of organic solvents, subpopulations of peripheral blood lymphocytes (PBLs) were analyzed. For this, the PBLs of nine floorers (aged 25–58 years, exposure time 8–35 years) were subsequently labelled with monoclonal antibodies OKT 4, OKT 8, OKT 11, anti-Leu 7 and anti-Leu 12. Analysis was made by a FACS IV cell sorter (Becton-Dickinson, USA). The control group consisted of matched pairs of healthy donors. In the exposed group we found a decrease in the OKT 11 (all) T cell fraction, a decrease in the OKT 4 helper cells, an increase in the anti-Leu 7 positive cells, mostly natural killer cells, an important increase …
Assessment of the cytotoxic potential of an aqueous-ethanolic extract from Thalassia testudinum angiosperm marine grown in the Caribbean Sea
2018
Abstract Objectives Reported antioxidant, anti-inflammatory and neuroprotective properties for one aqueous-ethanolic extract from Thalassia testudinum which grows in the Caribbean Sea compelled us to explore about extract cytotoxic effects. Methods Cell viability was assayed on tumour (HepG2, PC12, Caco-2 and 4T1) and non-tumour (VERO, 3T3, CHO, MCDK and BHK2) cell lines. The extract effects upon primary cultures of rat and human hepatocytes and human lymphocytes were assayed. Key findings The extract exhibited cytotoxicity against cancer cells compared to normal cells, and the IC50 values were 102 μg/ml for HepG2, 135 μg/ml for PC12, 165 μg/ml for Caco-2 and 129 μg/ml for 4T1 cells after 4…
Cocaine abuse determination by ion mobility spectrometry using molecular imprinting
2016
A cocaine-based molecular imprinted polymer (MIP) has been produced by bulk polymerization and employed as selective solid-phase extraction support for the determination of cocaine in saliva samples by ion mobility spectrometry (IMS). The most appropriate conditions for washing and elution of cocaine from MIPs were studied and MIPs were characterized in terms of analyte binding capacity, reusability in water and saliva analysis, imprinting factor and selectivity were established and compared with non-imprinted polymers. The proposed MIP-IMS method provided a LOD of 18μgL-1 and quantitative recoveries for blank saliva samples spiked from 75 to 500μgL-1 cocaine. Oral fluid samples were collec…
A comprehensive untargeted metabonomic analysis of human steatotic liver tissue by RP and HILIC chromatography coupled to mass spectrometry reveals i…
2011
Steatosis, or excessive accumulation of lipids in the liver, is a generally accepted previous step to the development of more severe conditions like nonalcoholic steatohepatitis, fibrosis, and cirrhosis. We aimed, to characterize the metabolic profile that defines simple steatosis in human tissue and to identify potential disturbances in the hepatic metabolism that could favor the switch to progressive liver damage. A total of 46 samples, 23 from steatotic and 23 from nonsteatotic human livers, were analyzed following a holistic LC-MS-based metabonomic analysis that combines RP and HILIC chromatographic separations. Multivariate statistical data analysis satisfactorily classified samples an…
Bias in Studies of Parental Self-reported Occupational Exposure and Childhood Cancer
2003
Several case-control studies have demonstrated positive associations between parental occupational exposures and childhood cancer. However, an overestimation of risk estimates due to recall bias is of concern. The magnitude and nature of this bias were explored using data from a German case-control study on childhood leukemia conducted between 1992 and 1997. A moderate overreporting of occupational exposures by fathers was observed, particularly for the prenatal period. Overreporting was most apparent when the time between exposure and interview was short. It was also found that job titles were no satisfactory substitute for information on specific occupational exposures. The results of thi…
Blue-yellow deficiency in workers exposed to low concentrations of organic solvents
1997
Objectives: To evaluate the effects of low concentrations of organic solvents on color vision. Methods: Color vision was examined in 24 workers exposed to mixtures of solvents and in 24 control subjects. Exposure to mixtures was below the threshold-limit values. Color vision ability was assessed using the Ishihara plates (to screen for congenital dyschromatopsia), the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2 (SPP2 test). Results: The comparatively less sensitive Farnsworth panel D-15 test failed to show any difference between the groups, but the Lanthony panel D-15 desaturated test as well as the SPP2 test showed…
Parental occupational exposure to organic solvents and anencephaly in Mexico
2009
Objective: To assess the relationship between parental occupational exposure to organic solvents, and the risk of anencephaly in Mexico. Methods: A case-control study was conducted based on the registers of the Epidemiological Surveillance System for Neural Tube Defects in Mexico; 151 cases of anencephaly of ≥20 weeks’ gestation were included. A control, born alive and without any apparent congenital malformations at birth, was selected for each case in the same maternity service in which the case was born. Information on occupational exposures, lifestyle habits, reproductive history, use of medicines, supplementation with multivitamins and folic acid, was obtained by a general questionnair…
The exposure of healthy volunteers to 200 ppm 1,1,1-trichloroethane increases the concentration of proinflammatory cytokines in nasal secretions
1999
Objectives: Irritating effects of organic solvents have usually been measured by means of questionnaires. The aim of the present study was to evaluate the sensitivity of different methods of detecting subclinical irritating effects. Methods: Twelve healthy, non-smoking students were exposed to 200 ppm and to 20 ppm 1,1,1-trichloroethane in an exposure chamber, using a crossover design. The amounts of interleukins (IL)-1β, IL-6 and IL-8 and prostaglandin E2 (PGE2) in nasal secretions were measured. Mucociliary transport time was determined with the saccharine test. Ciliary beat frequency of nasal epithelial cells was measured with video-interference contrast microscopy. Subjective symptoms w…
Crohn's disease: A comparative prospective study of transabdominal ultrasonography, small intestine contrast ultrasonography, and small bowel enema
2005
Background: Small intestine contrast ultrasonography (SICUS), when performed after distention of the small bowel lumen with an iso-osmolar polyethylene glycol electrolyte-balanced solution, shows high sensitivity (100%) and specificity (97%) in detecting small bowel abnormalities in patients who have not received a diagnosis but in whom there is a suspicion of intestinal diseases. The diagnostic yield of SICUS remains to be established in detecting small bowel lesions in patients with proven Crohn's disease (CD) in comparison with transabdominal ultrasonography (TUS), and in relationship to the experience of the operator, using small bowel enema (SBE) as the “gold standard.” Aim: The aim of…
In Vitro Percutaneous Penetration of Acyclovir from Solvent Systems and Carbopol 971-P Hydrogels: Influence of Propylene Glycol
2005
The mechanism underlying propylene glycol (PG) effects on acyclovir (ACV) penetration through human epidermis were studied. Solvent systems and Carbopol gels containing increasing percentage of PG (from 0% to 70%, w/w) were used. Viscosity studies of both vehicles were carried out to characterise the influence of rheological behaviour. In solvent systems skin permeation values of ACV increase as the concentration of PG increase yielding a maximum enhancement ratio (ER = 10) for 70% PG. The release rate of ACV from gels was determined. Higuchi's model was used to estimate the apparent diffusion coefficient of the drug. These values show a decrease as the content of PG in the vehicle increase…