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The effects of smoke and smoke fractions from tobacco and a substitute smoking material (NSM) on the DNA content of mammaliam cells in culture were measured. Tobacco smoke caused significant (P less than 0.001) changes in the DNA content of all the mammalian cells exposed compared with controls. NSM smoke did not have a significant effect on the DNA content of the exposed cells (P less than 0.95). Smoke from blends of NSM and tobacco caused changes in DNA content in proportion to the amount of tobacco in the mixtures. Condensate from cigarettes containing tobacco or blends of tobacco and NSM caused significant (P less than 0.001) changes in DNA content of mammalian cell populations in culture, whereas equal weights of condensate from NSM alone or NSM containing nicotine did not cause significant changes (P less than 0.05). NSM produces 28% of the weight of condensate per cigarette in comparison with tabacco and would, therefore, be expected to be far less biologically active than tobacco. Filtered smoke from cigarettes containing tobacco caused significant (P less than 0.001) changes in the DNA content of mammalian cells in culture. These changes were quantitatively similar to those caused by whole smoke suggesting that the gas phase of cigarette smoke is biologically more reactive than the particulate phase. The filtered smoke from the substitute smoking material NSM did not cause significant (P less than 0.95) changes in DNA content of cultured mammalian cells. Filtered smoke from blends of NSM and tobacco caused changes in DNA content in proportion to the amount of tobacco in the mixture.  相似文献   

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The effect of ethanol on mucus glycoprotein synthesis, intracellular modification, transport, glycosylation, and secretion was studied in rat gastric mucous cells. Preincubation of the in vitro translation mixture containing gastric mucous cells mRNA for 60 min with 0 to 120 mM ethanol caused a decrease in the synthesis of mucus glycoprotein apopeptide by up to 40%. The reduction in translation was time- and ethanol concentration-dependent. After 60 min, translation in the presence of 30, 60, and 120 mM ethanol decreased to 83.3 +/- 2.3%, 75.5 +/- 0.4%, and 63.6 +/- 2.6%, respectively. The experiments conducted with endoplasmic reticulum microsomes, preincubated with ethanol, and used in the studies of cotranslational translocation of the apomucin showed a 20% decrease in the transfer of mucus glycoprotein apopeptide to the lumen of endoplasmic reticulum microsomes. In the presence of ethanol, processing of mucus glycoprotein apopeptide in Golgi was also inhibited. During the initial 30 min of incubation with 0 to 120 mM ethanol, glycosylation seemed to proceed at the same rate in the samples with and without ethanol. However, during consecutive 30 min of incubation, glycosylation in the presence of 60 mM ethanol decreased by 30 to 35%, and with 120 mM ethanol was completely inhibited. Measurements of the effect of ethanol on the discharge of mucus glycoprotein from the intracellular stores revealed that, on average, the secretory output of the rat gastric mucosa exposed to ethanol liquid diet for 8 weeks decreased by 77% or more, and adherence of the glycoprotein to the gastric epithelium was weakened. Results indicate that ethanol inhibits synthesis, transport, and processing of gastric mucus glycoprotein, and that the processes taking place in different intracellular compartments contribute in the additive fashion and, are reflected in a dramatic decrease in the delivery of mucus glycoprotein to the gastric epithelial surfaces.  相似文献   

4.
The purpose of this study was to determine if hair nicotine and cotinine levels reflect relative exposure to environmental tobacco smoke (ETS) in subjects who worked in the hospitality industry, where public smoking was permitted. Hair samples from 26 subjects were analyzed by gas chromatograph/mass spectrometry techniques for nicotine and cotinine. An exposure gradient was shown for nicotine but not cotinine. Among nonsmokers, those working in bars where there are no public smoking restrictions had the highest hair nicotine levels, which were close to levels found in smokers. Nicotine measured in hair is useful as a biological marker for exposure to ETS from multiple sources. Bar workers in particular are exposed to high levels of ETS, which may adversely affect the health of nonsmokers.  相似文献   

5.
The rates of chlorination of Fe (528 to 921 K), Ni (890 to 1249 K), and Sn (340 to 396 K) in Cl2-He andCl2-Ar mixtures were measured. In the temperature range of the respective investigations the overall reaction products are gaseous: (FeCl3)2, NiCl2, and SnCl4. Transport through the gas film boundary layer at the surface of the sample plays a major role in controlling the rate of the reactions over large temperature ranges for all three metals. In the high-temperature range for iron (> 680 K) and nickel (> 993 K) as well as for the entire temperature range studied for tin, the transport of Cl22(g) through the gas film boundary layer to the surface of the sample controlled the rates for the experimental conditions in the present work. The transport of NiCl2(g) controlled the rate of the Ni-Cl2 reaction at lower temperatures. The rate of the Fe-Cl2 reaction at lower temperatures is controlled by a slow surface reaction between Cl2(g) and FeCl2(s) which covers the surface of the iron. The overall activation energy for the formation of the activated complex (FeCl3)2‡ is 23 kcal/g-atom Fe.  相似文献   

6.
Glutathione reductase (GR), glutathione peroxidase (GSH Px) and catalase (Cat) were determined in the kidneys of rats exposed to cigarette smoke for 3 months. Activity of the brush-border enzyme gamma-glutamyl transpeptidase (GGT), glutathione (GSH) and lipid peroxide levels (LPX) were also estimated in both, kidney homogenates and urine. Activities of GR, Cat, GGT and the levels of GSH were decreased in the kidney. However, the activities of GSH Px and LPX levels were increased. Urinary excretion of GGT, GSH and LPX were also higher. Fall in the activity of GR and rise in the activity of GSH Px, may perturb the reduced glutathione/oxidised glutathione ratio, which in turn could lead to increased LPX seen in chronic cigarette smoke exposure.  相似文献   

7.
This article describes the development of a mathematical model that predicts the time required for a metal sphere to melt in a metal bath under different fluid flow conditions. The sphere is made from the same metal as the bath. The model solves numerically the pertinent momentum and energy equations in three dimensions, employing the SIMPLER algorithm. For the case of a pure metal, the model uses the heat integration algorithm to account for the latent heat of fusion. For the situation of a metal alloy with long freezing range, it incorporates the enthalpy method to account for the latent heat of fusion. The model is validated extensively: first, by using Paterson’s analytical solution; second, by using the experimental results of Gallium melting in a rectangular enclosure; and third, by using experimental results involving ice spheres melting in water. The practical use of this model is to study the influence of various parameters in the sphere melting system. This study facilitates the detection of liquid metal velocity using the sphere melting technique.  相似文献   

8.
A new measure of subjective socioeconomic status (SES) was examined in relation to self-rated physical health in pregnant women. Except among African Americans, subjective SES was significantly related to education, household income, and occupation. Subjective SES was significantly related to self-rated health among all groups. In multiple regression analyses, subjective SES was a significant predictor of self-rated health after the effects of objective indicators were accounted for among White and Chinese American women; among African American women and Latinas, household income was the only significant predictor of self-rated health. After accounting for the effects of subjective SES on health, objective indicators made no additional contribution to explaining health among White and Chinese American women; household income continued to predict health after accounting for subjective SES among Latinas and African American women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

9.
Calcium, phosphorus and vitamin D metabolism were examined in 21 male and 13 female subjects with renal tubular dysfunction in the cadmium-polluted Jinzu River basin in Toyama prefecture, Japan. Multiple proximal renal tubular dysfunction was detected in all subjects showing increased FE beta 2-m and FFua, generalized aminoaciduria and renal glucosuria. Reduced ability of tubular reabsorption of phosphate resulted in hypophosphatemia in 31% of the women. Despite decreased tubular reabsorption of calcium, the level of serum calcium remained normal in all subjects. Serum 1,25-dihydroxyvitamin-D [1,25(OH)2D], which is produced in the proximal tubules through 1 alpha-hydroxylation from 25-hydroxyvitamin-D [25OHD], was normal or increased to more than 60pg/ml. The serum level of 1,25(OH)2D was inversely related to creatinine clearance in both the men (p < 0.05) and women (p < 0.01). Serum iPTH was slightly increased to more than 0.9 mg/ml, whereas the levels of other hormones, including 25OHD, calcitonin, thyroxine (T4) and triiodothyronine (T3) were normal. The serum alkaline phosphatase activity and serum osteocalcin concentration were significantly increased compared to those of controls in both sexes. Bone loss detected by the measurement of bone density was prominent in female subjects. These results support the hypothesis that the serum phosphate concentration is more important than the serum concentration of 1,25(OH)2D for abnormalities of bone metabolism in cadmium-induced renal tubular dysfunction.  相似文献   

10.
Diclofenac antiserum was previously developed and used to detect protein adducts of metabolites of dichlofenac in livers of mice and rats. In this study, the antibody has been used to facilitate the purification of a major 51 kDa microsomal adduct of diclofenac from the liver microsomes of male rats that were treated with diclofenac. The adduct was identified as male-specific cytochrome P4502C11 based on its N-terminal amino acid sequence, reaction with a cytochrome P4502C11 antibody, and by its absence from liver microsomes of diclofenac-treated female rats. When diclofenac was incubated with liver microsomes of control rats in the presence of NADPH, only the 51 kDa adduct was produced. The formation of the adduct was inhibited by a cytochrome P4502C11 monoclonal antibody, but not by reduced glutathione or N-alpha-acetyl-L-lysine. No adduct was detected when diclofenac was incubated with liver microsomes from female rats. Moreover, adduct formation in vivo appeared to lead to a 72% decrease in the activity of cytochrome P4502C11. The results indicate that cytochrome P4502C11 metabolizes diclofenac into a highly reactive product that covalently binds to this enzyme before it can diffuse away and react with other proteins.  相似文献   

11.
The present state of knowledge regarding “regular” deformation bands (DBs) is reviewed in the light of some recent observations on DBs in compressed polycrystalline aluminum. These are slablike volume elements within which different selections of slip systems operate, always fewer than required for homologous deformation, in opposition to the assumption that grains deform as units which are common to all, the Sachs, the Boas and Schmid, and the Taylor/Bishop and Hill models. The need for a better integration of this knowledge with not only the origin of deformation textures but also more generally with the theory of plastic deformation is pointed out.  相似文献   

12.
The structure and mathematical model of PARATI, a detailed computer programme developed for the assessment of the radiological consequences of an accidental contamination of urban areas, is described with respect to the scenarios used for the estimation of exposure fields in a village or town, the models for the initial and secondary contamination with the radionuclide 137Cs, the concepts for calculating the resulting radiation exposures and the changes with time of the contamination and radiation fields. Kerma rates at various locations in tropical urban areas are given, and the contribution of different contaminated surfaces to these rates after dry or wet deposition are discussed.  相似文献   

13.
The safety, pharmacokinetics, and antiretroviral activity of lamivudine alone and in combination with zidovudine was studied in pregnant women infected with human immunodeficiency virus type 1 (HIV-1) and their neonates. Women received the drugs orally from week 38 of pregnancy to 1 week after delivery. Neonate therapy began 12 h after delivery and continued for 1 week. Both treatment regimens were well-tolerated in women and newborns. Lamivudine and zidovudine pharmacokinetics in pregnant women were similar to those in nonpregnant adults. Lamivudine and zidovudine freely crossed the placenta and were secreted in breast milk. Neonatal lamivudine clearance was about half that in pediatric patients; zidovudine clearance was consistent with previous reports. HIV-1 RNA could be quantified in 17 of the 20 women. At the onset of labor/delivery, mean virus load had decreased by approximately 1.5 log10 copies/mL in both treatment cohorts. Although not definitive for HIV-1 infection status, all neonates had HIV-1 RNA levels below the limit of quantification at birth and at ages 1 and 2 weeks.  相似文献   

14.
Cocaine and its metabolites were measured in urine, meconium, and amniotic fluid specimens collected from 30 maternal-infant pairs with histories of prenatal cocaine use. Cocaine, benzoylecgonine, and ecgonine methyl ester were measured by isotope dilution gas chromatography-mass spectrometry. Mothers were interviewed at delivery regarding their cocaine use during pregnancy. There was qualitative agreement between the results of drug determinations in maternal urine, amniotic fluid, infant urine, and meconium. Although all of the mothers in this study admitted to using cocaine during their pregnancy, cocaine or its metabolites were detected only in the 20 cases in which cocaine was used within 3 weeks before delivery. We conclude that when sufficiently sensitive analytic methods are used, maternal urine, infant urine, and meconium analyses yield equivalent results for detection of prenatal cocaine exposure. Importantly, neither meconium nor urinary drug measurements detected cocaine exposure when the last reported use was prior to 3 weeks before delivery.  相似文献   

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The distribution of the protein energy ratio indicators (Pe%), amino acid score and protein value (NDpCal%) in the three daily meals (breakfast, lunch and dinner) of the diet of pregnant women from Santa María Cauqué, Guatemala, was studied. The results were compared with those obtained for the total daily food intake. The differences observed were not significant, confirming the validity of the determination of amino acid score, Pe% and NDpCal% in the foods consumed during the whole day in this type of populations. It also reflects the nutritional benefit of the food pattern, since protein utilization would not be decreased by a different distribution of protein quality and concentration throughout the three daily meals. The variability among individuals of Pe% intake, amino acid score and NDpCal% gave the following values: 16.0, 9.3 and 15.6, respectively. It is noteworthy to add that the variability of Pe% observed is similar to that reported for populations of developed countries.  相似文献   

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Processes of adsorption of rotaviruses of different strains by enterol sorbents on the basis of hydrogel of methylsilicic acid with bi- and trivalent ions of 3d-metals (iron, cobalt, copper) fastened in their matrix have been studied.  相似文献   

20.
A consistent research finding in creativity research has been the tendency of poets--especially female poets--to suffer from mental illness. We explore (a) Why poets? and (b) Why female poets? We posit that poetry may attract those with a predisposition toward illness, the domain of poetry may particularly reward those who exhibit illness, and unusual aspects of the domain of poetry writing may increase the likelihood of poets succumbing to illness. These domain-specific aspects of writing poetry affect men and women alike. In addition, the greater difficulty that women tend to experience in ignoring extrinsic motivational constraints may cause successful female poets to have an even higher incidence of psychological stress, and of mental illness, than male poets. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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