Cytogenetic analysis of peripheral blood lymphocytes in glass workers occupationally exposed to mineral oils

Chromosome aberration tests were carried out in a group of 31 pressed glass makers operating an automatic line of press-and-blow machines known to release mineral oil mists containing relatively high concentrations of the mutagenic chemicals belonging to a class of polycyclic aromatic hydrocarbons (PAH). The workers were exposed to the mineral oil aerosol levels that did not exceed the Czechoslovak maximum allowable concentration limit of 5 mg . m-1 of air. The tests revealed that the frequency of aberrant cells (% AB.C.) and the value of breaks per cell (B/C) ratio found in mineral oil-exposed workers were increased significantly, accounting for 4.65 +/- 0.29% AB.C. (0.0532 B/C) vs. 1.13 +/- 0.19% AB.C. (0.0113 B/C) seen in matching controls. Also, a higher rate of dicentrics, reciprocal translocations and cells with pulverization was observed in this group of glass workers. These finding are considered as evidence suggesting that these workers might experience an increased risk of genetic injury due to exposure to mineral oil mists.     

Chromosomal aberrations, SCE and urine mutagenicity in workers occupationally exposed to cytostatic drugs

The genetic risk run by workers occupationally exposed to chemicals, including the newly developed cytostatics, was assessed in large chemical laboratories. The exposed group comprising 38 people consisted of chemists, laboratory assistants and pilot plant workers. The average rate of aberrant cells in peripheral blood lymphocytes (AB.C). was 3.9% and the value of break/cell ratio was 0.046. The group of matched controls (N = 18) was found to have 1.5% of AB.C. and 0.020 breaks/cell. In the exposed group, there were, on average, 8.94 SCEs/cell, and in controls, 5.81. Urine mutagenicity tests on Salmonella typhimurium tester strain TA98 revealed a significant increase of activity in 23 (64%) out of 36 urine samples tested as compared to the control group (N = 19) with 4 (21%) positive urine samples. Strain TA100 showed only a weak response to urine mutagens.     

Chromosomal abnormalities in soft coal open-cast mining workers

Chromosome aberration tests on cultured peripheral blood lymphocytes were carried out in two groups of open-cast mining workers engaged in stripping operations (Group I) and digging operations (Group II), in a group of coal cleaning plant workers used as a positive control, and in a group of nonexposed subjects serving as matching controls. Peripheral blood samples in group I and group II miners were collected in March and June of 1984, the antimutagenic potential of long-term prophylactic vitamin administrations (1 g of ascorbic acid given daily for a period of 3 months and 100 mg of vitamin A a day for two 5-day cycles) initiated after the first blood sampling was tested in group II miners. The frequency of aberrant cells (% AB.C.) found in the cultured lymphocytes of group I miners was increased at both times of measurement (2.41% AB.C. and 2.29% AB.C.), in group II miners given the vitamin prophylaxis it dropped significantly (P greater than 0.01) from the initial 3.16% AB.C. in March to 1.77% AB.C. in June, and in the group of coal cleaning plant workers (1.30% AB.C.) it was more or less equal to that of matching controls (1.21% AB.C.). Implicitly, coal dust alone can hardly be made responsible for the rise in % AB.C. It appears that the increase in frequency of chromosome aberrations observed in soft coal open-cast mining workers rather reflects an increased risk of genetic injury due to exposure to ever-present fumes and fire hazards that may give rise to the mutagenic chemicals belonging to a class of polycyclic aromatic hydrocarbons. The antimutagenic effect of ascorbic acid prophylaxis was characterized by a significant drop in % AB.C. and a speed-up of the lymphocyte cell cycle expressed as the proliferating rate index (PRI) whose value rose from the original 1.41 to 1.69, thus reaching the PRI value of matching controls (1.63).     

Correlation of human lymphocyte SCE frequency with smoking history

The relationship between the level of occupational exposure to epichlorohydrin (ECHH) and the clastogenic effect was studied on a group of 33 workers. The effect of ECHH was assessed by differences in the frequency of chromosome aberrations in peripheral blood lymphocytes in ECHH-exposed and control groups. In the group exposed to the average ECHH concentration, 0.384 mg X m-3, during the last 6 months, the cytogenetic analysis revealed 2.00 +/- 0.23% AC (aberrant cells) (0.0203 B/C, breaks per cell) as compared with 1.68 +/- 0.23% AC (0.0172 B/C) in the matching controls. These results indicate that an average concentration lower than 0.40 mg X m-3 ECHH in the working atmosphere has no significant clastogenic effect on human peripheral lymphocytes.     

武汉东湖桡足类生物量及生产量的初步研究

本文主要论述1980—1982年武汉东湖桡足类生物量及生产量的测算结果。三周年来在东湖Ⅰ、Ⅱ采样站上共观察到5种剑水蚤:广布中剑水蚤(Mesocyclops leuckarti)、近邻剑水蚤(Cyclops vicinus vicinus)、透明温剑水蚤(Thermocyclops hyalinus)、台湾温剑水蚤(Thermocyclops taihokuensis)、锯缘真剑水蚤(Eucyclops serrulatus)和5种哲水蚤:球状许水蚤(Schmackeria forbesi)特异荡镖水蚤(Neutrodiaptomus incongruens)、右突新鏢水蚤(Neodiaptomus schmackeria)、中华原鏢水蚤(Eodiaptomus sinensis)、汤匙华哲水蚤(Sinocalanus dorrii)。其总年平均生物量为321.74毫克干重/平方米。其中剑水蚤为194.70毫克干重/平方米,占60.51%;哲水蚤为127.04毫克干重/平方米,占39.49%。总年生产量为16.959克干重/平方米。其中剑水蚤为11.225克干重/平方米,占66.19%;哲水蚤为5.734克干重/平方米,占33.81%。年P/B比为52.55;其中剑水蚤为57.63,哲水蚤为46.02。各发育阶段的年平均生物量以桡足幼体最高,其次为无节幼体,卵最低。年生产量则以无节幼体最高,其次为桡足幼体,卵最低。从各种类所占总年平均生物量、年生产量的百分比值来看,广布中剑水蚤的比值最大,其次为球状许水蚤、近邻剑水蚤和特异荡鏢水蚤。       

Analysis of chromosomes in peripheral blood lymphocytes of styrene-exposed workers

A group of 11 workers exposed to an average of 253 mg.m-3 styrene had no elevation of the frequencies of chromosomal aberrations in their peripheral lymphocytes when compared to 11 healthy persons.     

补增UV-B辐射对香蕉叶片光合作用和叶氮在光合碳循环组分中分配的影响

补增UV－B辐射的香蕉叶片光下呼吸速率（Rd））和不包括光下呼吸的CO2补偿点（г*）,分别为0.33μmol·m-2·s-1和46.5μl·L-1,较对照植株分别高5.6％和10.0％。在较高CO2浓度（>340μl·L-1）条件下的An/θp关系最初直线部分斜率,即表观量子产率(α-A)为0.023±0.007,而补增UV-B辐射处理的植株则降低13.0％,光能转换效率（δ）亦降低28.6％,表明UV-B辐射明显降低αA和δ。在高θp（1100μmol·m-2·s-1）和Ci<200μl·L-1条件下,对照植株的An/Ci关系为An=0.028Ci+1.44,补增UV-B辐射处理的植株则为An=0.021Ci+1.01,UV-B辐射降低羧化限制速率。最大羧化速率（Vcmax）和电子传导速率的光饱和值（Jmax）亦较低,补增UV-B辐射的叶片,叶氮在Rubisco的分配系数（PR）和叶氮在生物力能学组分的分配系数（PB）分别较对照低8.1％和3.0％,叶氮分配到类囊体膜捕光色素蛋白组分的则略见增高,UV-B辐射降低叶氮在光合循环组分的分配。     

Biomonitoring of occupational exposure to styrene in a plastics lamination plant.

A comprehensive approach to biological monitoring of 44 workers occupationally exposed to styrene in a hand lamination plant was performed by using several end-points: styrene in workplace air, styrene in exhaled air, styrene in blood, DNA strand breaks (SBs) and oxidised bases in mononuclear leukocytes, chromosomal aberrations in lymphocytes, immune parameters and genotyping of polymorphic genes of some xenobiotic-metabolizing enzymes (CYP 1A1, EPHX, GSTM1 and GSTP1). We found a significantly higher number of DNA SBs, measured by a modified comet assay, in mononuclear leukocytes of the styrene-exposed workers compared with results from 19 unexposed controls (P<0.001). A fairly strong correlation was observed between SBs and years of exposure (P<0.001, r=0.545). The styrene-exposed workers also showed a significantly increased frequency of chromosomal aberrations (P<0.0001 for highly exposed group, P<0.004 for medium-exposed group, and P=0.0001 for low-exposed group). The proliferative response of T-lymphocytes stimulated with concanavalin A was significantly suppressed in people exposed to styrene (P<0.05). We recorded a significant increase of the percentage of monocytes in differential white blood cell counts in the exposed group (P<0.05). Using flow cytometry, we found an increased expression of adhesion molecules CD62L, CD18, CD11a, CD11b, CD49d and CD54 in the exposed workers as compared with the control group (P<0.05).     

Sister-chromatid exchanges in lymphocytes from styrene-exposed boat builders

Sister-chromatid exchanges (SCE) were measured in peripheral blood lymphocytes from 40 workers in the boat-building trade. Twenty of these workers were exposed to significant amounts of styrene. The mean air concentration of styrene in the breathing zone of the boat builders was 209 mg/m3 in the 7 exposed current smokers and 230 mg/m3 in the 13 exposed non-smokers. Urinary styrene metabolites were also measured and the mean mandelic acid/creatinine ratios in the exposed, smokers was 275 mg/g, and in the exposed, non-smokers 323 mg/g. The SCE frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls, although smoking significantly induced SCE in these workers.     

氮磷添加对麦冬根部养分浓度及其化学计量比的影响

以城市地被植物麦冬(Ophiopogon japonicus(Thunb.)Ker-Gawl.)为研究对象,研究了土壤中添加氮(N)磷(P)后对植物根部N、P养分及其化学计量比的影响。结果表明,实验监测期间(10-12月),麦冬根部N浓度平均值表现为N(5gm-2) P(1gm-2)处理>N(5gm-2)处理=P(1gm-2)处理>对照,根部P浓度和N:P比差异不显著(P>0.1)。而监测期间的N、P月份动态结果表明,同对照相比,N处理、P处理和N P处理的麦冬根部N、P浓度和N:P比的差异性均表现为监测前期(10月)较大,中后期(11-12月)较小的变化趋势。这说明麦冬能保持其根部N、P水平的稳定性,具有较强的应对N沉降的能力,且补充P肥可增强这种能力。因此,麦冬可在大气沉降严重的地区应用和推广。     

Chromosomal aberration frequencies determined by conventional methods: Parallel increases over time in the region of a petrochemical industry and throughout the Czech Republic

The rationale for cytogenetic monitoring to determine if safe maximum allowable concentrations (MAC) of genotoxic chemicals are being maintained in a workplace is that exposure levels that do not increase chromosomal aberration frequencies are without harmful effects. Such monitoring, widely used in occupational health programs in the Czech Republic (CR), includes workers exposed to 1,3-butadiene (BD) or other chemicals. Studies of BD exposed workers in the years 1992, 1993, 1994, 1998, and 2004 compared mean frequencies of cells carrying chromosomal aberrations (frequency of aberrant cells=%AB.C.) in exposed workers with those in non-exposed matched controls in the same plant or in other individuals living in the region of the same petrochemical industry. Workers potentially exposed to acrylonitrile at this site were also evaluated in 2000, along with another unexposed matched control group. The %AB.C. values of exposed workers and their controls were also compared with reference values determined for normal individuals (ages 20-59 years) throughout the CR. Substantial discrepancies were noted between subjects in the region of the petrochemical industry (exposed workers and controls) for the years 2000 and 2004 and the reference CR-wide normal values that had been determined during an earlier time period. The matched non-exposed controls at the petrochemical industry site showed a mean %AB.C. value of 1.56+/-1.23% (N=25) in 1998; this rose to a mean of 2.65+/-2.29% (N=33) in 2000. In 2004, values for non-exposed matched controls at the industry site were 2.64+/-1.75% for males (N=25) and 2.38+/-1.74% (N=26) for females. However, the earlier determined CR-wide %AB.C. mean reference values for normal individuals were 1.77+/-1.16% (N=1305) for the interval 1977-1988 and 1.45+/-1.17% (N=2140) for the interval 1991-1999. As both reference values are substantially lower than those determined in 2000 and 2004 for the non-exposed matched controls at the petrochemical industry site, an analysis of the CR-wide mean normal individual reference values for this same 2000-2004 period was conducted. Unexpectedly, it was found that this reference value too had risen to 1.95+/-1.36% (N=1045) and was comparable to the concurrent matched control values at the petrochemical industry site where the monitoring studies were conducted. This substantial increase in %AB.C. values in 2000 and 2004, therefore, has occurred throughout the CR and is probably unrelated to chemicals uniquely present at the petrochemical industry site.     

Evaluation of long-term occupational exposure to styrene vapor on olfactory function

The primary sensory neurons of the olfactory system are chronically exposed to the ambient environment and may therefore be susceptible to damage from occupational exposure to many volatile chemicals. To investigate whether occupational exposure to styrene was associated with olfactory impairment, we examined olfactory function in 2 groups: workers in a German reinforced-plastics boat-manufacturing facility having a minimum of 2 years of styrene exposure (15-25 ppm as calculated from urinary metabolite concentrations, with historical exposures up to 85 ppm) and a group of age-matched workers from the same facility with lower styrene exposures. The results were also compared with normative data previously collected from healthy, unexposed individuals. Multiple measures of olfactory function were evaluated using a standardized battery of clinical assessments from the Monell-Jefferson Chemosensory Clinical Research Center that included tests of threshold sensitivity for phenylethyl alcohol (PEA) and odor identification ability. Thresholds for styrene were also obtained as a measure of occupational olfactory adaptation. Styrene exposure history was calculated through the use of past biological monitoring results for urinary metabolites of styrene (mandelic acid [MA], phenylglyoxylic acid [PGA]); current exposure was determined for each individual using passive air sampling for styrene and biological monitoring for styrene urinary metabolites. Current mean effective styrene exposure during the day of olfactory testing for the group of workers who worked directly with styrene resins was 18 ppm styrene (standard deviation [SD] = 14), 371 g/g creatinine MA + PGA (SD = 289) and that of the group of workers with lower exposures was 4.8 ppm (SD = 5.2), 93 g/g creatinine MA+PGA (SD = 100). Historic annual average exposures for all workers were greater by a factor of up to 6x. No differences unequivocally attributable to exposure status were observed between the Exposed and Comparison groups or between performance of either group and normative population values on thresholds for PEA or odor identification. Although odor identification performance was lower among workers with higher ongoing exposures, performance on this test is not a pure measure of olfactory ability and is influenced by familiarity with the stimuli and their sources. Consistent with exposure-induced sensory adaptation, however, elevated styrene thresholds were significantly associated with higher occupational exposures to styrene. In summary, the present study found no evidence among a cross-section of reinforced-plastics workers that current or historical exposure to styrene was associated with a general impairment of olfactory function. When taken together with prior studies of styrene-exposed workers, these results suggest that styrene is not a significant olfactory toxicant in humans at current exposure levels.     

Long-term study on workers occupationally exposed to ethylbenzene

Ethylbenzene is synthesized from benzene; subject to catalytic dehydrogenation it yields styrene, a raw material for the production of synthetic rubber and plastics. Long-term biomonitoring of occupational ethylbenzene exposures, carried out in the past 20 years in some 200 ethylbenzene-production workers, revealed this substance to pose little hazard to human health. As it turned out, mandelic acid concentrations in these workers' urine never exceeded 3.25 mmol.l-1 and none of the exposed showed damage to hematopoiesis and/or liver tissue. Over the last 10 years no case of malignancy has been recorded in this industrial facility belonging to a larger chemical complex where the overall incidence of cancer is about 3 times the national average. Today's low-level ethylbenzene exposures would make it fully justifiable if the present-day MAC limits, both whole-shift (200 mg.m-3) and peak (1,000 mg.m-3), were to be halved, i.e. to be lowered to 100 mg.m3 and 500 mg.m3 respectively. These newly recommended limit values are no more exceeded nowadays.     

Determination of styrene and styrene-7,8-oxide in human blood by gas chromatography–mass spectrometry

Methods of isotope-dilution gas chromatography–mass spectrometry (GC–MS) are described for the determination of styrene and styrene-7,8-oxide (SO) in blood. Styrene and SO were directly measured in pentane extracts of blood from 35 reinforced plastics workers exposed to 4.7–97 ppm styrene. Using positive ion chemical ionization, styrene could be detected at levels greater than 2.5 μg/l blood and SO at levels greater than 0.05 μg/l blood. An alternative method for measurement of SO employed reaction with valine followed by derivatization with pentafluorophenyl isothiocyanate and analysis via negative ion chemical ionization GC–MS–MS (SO detection limit=0.025 μg/l blood). The detection limits for SO by these two methods were 10–20-fold lower than gas chromatographic assays reported earlier, based upon either electron impact MS or flame ionization detection. Excellent agreement between the two SO methods was observed for standard calibration curves while moderate to good agreement was observed among selected reinforced plastics workers (n=10). Levels of styrene in blood were found to be proportional to the corresponding air exposures to styrene, in line with other published relationships. Although levels of SO in blood, measured by the direct method, were significantly correlated with air levels of either styrene or SO among the reinforced plastics workers, blood concentrations were much lower than previously reported at a given exposure to styrene. The two assays for SO in blood appear to be unbiased and to have sufficient sensitivity and specificity for applications involving workers exposed to styrene and SO during the manufacture of reinforced plastics.     

β-catenin、cyclinD1在胸腺肿瘤中的表达及意义

目的：研究β-catenin、cyclinD1在胸腺肿瘤的表达及其意义。方法：采用免疫组化pv6000法检测69例胸腺肿瘤中β-catenin及cyclinD1的表达。结果：β-catenin与cyclinD1在胸腺肿瘤中的阳性表达率均为（53.62%）明显高于正常胸腺组织（0%）（P=0.027）。β-catenin的阳性表达的差异在A、AB、B1、B2、B3及C型胸腺肿瘤各型之间存在统计学意义（X2=24.676,P〈0.01）。其表达的在A、AB及B1型与B2、B3及C型（无/低度危险组肿瘤与中/高度危险组肿瘤）之间表达的差异存在统计学意义（X2=21.955,P〈0.01）。CyclinD1在A、AB、B1、B2、B3及C型胸腺肿瘤中的阳性表达的差异存在统计学意义（X2=14.393,P=0.013）。其表达在A、AB及B1型与B2、B3及C型（无/低度危险组肿瘤与中/高度危险组肿瘤）之间表达的差异存在统计学意义（X2=10.470,P=0.001）。在胸腺肿瘤中,β-catenin的表达与cyclinD1表达呈正相关关系（r=0.449,P〈0.01）。结论：β-catenin、cyclinD1对于判定胸腺肿瘤的恶性程度可能有重要的参考价值。Wnt/β-catenin信号传导通路在胸腺肿瘤的发生过程中可能发挥重要作用。     

Chromosomal aberrations and sister-chromatid exchanges in workers exposed to styrene

Few studies exist about chromosomal damage in workers occupationally exposed to styrene. In the present study, chromosomal aberrations and SCEs were analyzed from cultures of peripheral lymphocytes of workers employed in 6 different reinforced-plastics industries with styrene air exposure levels ranging from 30 to 400 mg/mc. A control group was selected on the base of sex, age and smoking habit. We examined 50-h cultures (for chromosomal-aberrations) and 72-h cultures (for SCEs) for each individual.All workers exposed to styrene, as compared with controls, showed significantly increased frequencies of chromosomal aberrations, while SCEs were significantly increased at 4 of the 6 plants. High SCE values appeared with styrene air concentrations higher than 200 mg/mc.Apart from the possible presence and role of other interfering chemicals in the various plants, chromosomal aberrations seem to be more sensitive than SCEs for the detection of chromosomal damage caused by exposure to low doses of styrene.     

Effect of ascorbic acid prophylaxis on the frequency of chromosome aberrations, urine mutagenicity and nucleolus test in workers occupationally exposed to cytostatic drugs

The genetic risk of workers occupationally exposed to a series of newly developed cytostatic drugs and the presumed antimutagenic potential of ascorbic acid (AA) were studied in a group of 38 chemical laboratory personnel examined for chromosome aberrations in lymphocytes, urine mutagenicity and nucleolar RNA activity before and after a 6-month prophylactic administration of AA at daily doses of 1 g for 5 days a week. Chromosome aberration tests revealed elevated aberrant cell (AB.C) rates both prior to and after AA supplementation (3.9% and 3.65% of AB.C., respectively). These values were significantly higher than those found in 18 non-exposed matching controls (1.05% of AB.C.). Tests for mutagenic activity in the urine of drug-exposed workers revealed 64% positive urine samples prior to vitaminization and 60% positive urine specimens after it; positive urine samples in the group of controls accounted for 21% of samples. In the nucleolus test, numbers of inactivated micronuclei in the exposed were initially higher than those of controls (33.4% versus 24.3%), but dropped to 20.5% after AA supplementation. These findings show that AA prophylaxis alone cannot substantially reduce the hazards associated with exposure to anti-cancer drugs.     

Chromosomal aberrations and sister-chromatid exchanges in workers exposed to styrene

Few studies exist about chromosomal damage in workers occupationally exposed to styrene. In the present study, chromosomal aberrations and SCEs were analyzed from cultures of peripheral lymphocytes of workers employed in 6 different reinforced-plastics industries with styrene air exposure levels ranging from 30 to 400 mg/mc. A control group was selected on the base of sex, age and smoking habit. We examined 50-h cultures (for chromosomal-aberrations) and 72-h cultures (for SCEs) for each individual. All workers exposed to styrene, as compared with controls, showed significantly increased frequencies of chromosomal aberrations, while SCEs were significantly increased at 4 of the 6 plants. High SCE values appeared with styrene air concentrations higher than 200 mg/mc. Apart from the possible presence and role of other interfering chemicals in the various plants, chromosomal aberrations seem to be more sensitive than SCEs for the detection of chromosomal damage caused by exposure to low doses of styrene.     

Increases in chromosome aberrations and in abnormal sperm morphology in rubber factory workers

Subjects working at a rubber plant in a chemicals warehouse or in calandering and bambury units were analyzed for both sperm parameters and structural chromosome aberrations in peripheral blood lymphocytes. Sperm analysis war performed in a group of 24 workers for comparison with fertile (n = 24) and infertile (n = 24) control groups. The statistical analyses of semen volume, vitality and sperm count did not show significant differences between exposed and fertile groups but significant differences were found from the infertile group. A significantly lower proportion of normal sperm head shapes was found in exposed subjects when compared to the fertile group (40.1 vs. 57.8). Seven exposed workers were re-analyzed 1 year and their sperm parameters did not change. The cytogenetic analysis showed a significant increase (3.90%) in the percentage of cells with aberrations in bambury workers (n = 11). However, no differences were found between calandering workers (n = 8) and control subjects (n = 10). Workplace air samples taken on the day of tissue sampling did not show any increase above the Cuban maximal allowed concentration for benzo[a]pyrene or toluene.     

阿拉善荒漠典型植物叶片碳、氮、磷化学计量特征

荒漠植物在水分限制、营养元素相对匮缺的条件下,经过长期的进化适应形成了自身独特的生理生态和生态化学计量特征。在阿拉善荒漠选择52个典型群落类型,分析和研究了54种荒漠植物叶片的碳、氮和磷的化学计量特征。结果表明:荒漠植物叶片的碳(C mg/g)、氮(N mg/g)和磷(P mg/g)含量变幅较大,分别为(379.01±55.42)mg/g、(10.65±7.91)mg/g和(1.04±0.81)mg/g,变异系数分别为0.15、0.74和0.78;C/N、C/P、和N/P分别为66.70±60.81、683.16±561.94、11.53±5.06。元素间相关性分析表明,叶片的C和N不相关(P0.05),C与P显著正相关(P0.05),N和P极显著正相关(P0.01)。从植物功能型的角度分析发现,灌木和1年生草本植物对C的存储能力较低;占整体67%的灌木叶片的N、P含量最低,导致总体N、P含量较低;多年生草本和1年生草本植物叶N含量与灌木植物叶片和整体N含量无差别,而P含量明显高于灌木植物叶片和整体P含量且N/P明显低于灌木植物叶片和总体N/P,导致总体N/P较低。该研究结果与全球和中国尺度的研究相比发现,荒漠植物叶片C、N、P含量和N/P明显偏低,N/P14说明阿拉善荒漠植物在受N、P共同作用的同时更易受N限制。