Meat consumption and risk of lung cancer: evidence from observational studies

BACKGROUND

A number of epidemiological studies have reported inconsistent findings on the association between meat consumption and lung cancer.

DESIGN

We therefore conducted a systematic review and meta-analysis to investigate the relationship between meat consumption and lung cancer risk in epidemiological studies.

RESULTS

Twenty-three case-control and 11 cohort studies were included. All studies adjusted for smoking or conducted in never smokers. The summary relative risks (RRs) of lung cancer for the highest versus lowest intake categories were 1.35 (95% confidence interval (CI) 1.08-1.69) for total meat, 1.34 (95% CI 1.18-1.52) for red meat, and 1.06 (95% CI 0.90-1.25) for processed meat. An inverse association was found between poultry intake and lung cancer (RR = 0.91, 95% CI 0.85-0.97), but not for total white meat (RR = 1.06, 95% CI 0.82-1.37) or fish (RR = 1.01, 95% CI 0.96-1.07).

CONCLUSIONS

The relationship between meat intake and lung cancer risk appears to depend on the types of meat consumed. A high intake of red meat may increase the risk of lung cancer by about 35%, while a high intake of poultry decreases the risk by about 10%. More well-designed cohort studies on meat mutagens or heme iron, meat cooking preferences, and doneness level are needed to fully characterize this meat-lung cancer association.

Isolation and characterization of Streptomyces spp. strains F-6 and F-7 capable of decomposing alkali lignin

Biodegradation and bioconversion of lignin are the result of the combined action of fungi, bacteria and actinomycetes. Through screening from forest soil, two novel isolated actinomycete strains were identified as Streptomyces spp. strains F-6 and F-7 by their morphology, cultural characteristics and high homology to the 16S rRNA gene. Both strains possessed laccase and manganese peroxidase activities. Laccase activity produced by strain F-6 was up to 935.4 U g(-1) dry cell weight. More than 50% of alkali lignin was removed by strains F-6 and F-7 in 12 days of incubation. GC-MS analysis of the biodegraded products showed strain F-6 converted lignin into phenol and broken phenol compounds. The two strains could co-culture with white-rot fungus, and the combined actinonycete-fungus system decomposed alkali lignin effectively.

A huge malignant peripheral nerve sheath tumor with hepatic metastasis arising from retroperitoneal ganglioneuroma

Ganglioneuromas (GNs) are the rarest and most benign of the neuroblastic tumors. We experienced a case of huge retroperitoneal GN which differentiated into malignant peripheral nerve sheath tumors (MPNST) with hepatic metastasis. The tumor was located in the upper right quarter of the abdomen and pressed the right lobe of the liver, which was initially misdiagnosed as a liver carcinoma. The tumor shared blood supply with the right liver lob and had rich blood supplies from the abdominal aorta, renal artery and hepatic artery. It was also associated with skin pigment and recurrence shortly following resection. Our finding demonstrated that MPNST is a potent invasive malignant tumor and metastasis earlier with very poor prognosis.

A quantitative study of monochromatic X-ray transmission through zinc wires

X-ray transmission through zinc wires of various diameters has been investigated systematically at different beam energies and sample-to-detector distances at the Shanghai Synchrotron Radiation Facility. This analysis shows that the experimentally measured transmission differs significantly from the theoretical estimation unless an appropriate point-spread function/line-spread function (PSF/LSF) is incorporated in the analysis. A number of other possible factors which may contribute to the observed inconsistencies were also assessed and these factors included higher harmonics and fluorescence; however, it was determined that these were not the dominant contributors underlying the inconsistencies. The investigation has demonstrated that the PSF/LSF is a major factor for consideration in quantitative X-ray micro-computed tomography.

A rare skin presentation of Penicillium marneffei infection in an AIDS patient

Penicillium marneffei is an opportunistic fungal pathogen in HIV disease. We report the case of a patient with AIDS who presented with general weakness and generalized skin rashes. No specific allergic history or recent medication were reported. The skin lesions disappeared after adequate antifungal therapy. A blood culture obtained from the patient confirmed the presence of P. marneffei, infection which is characterized by cutaneous umbilicated lesions in AIDS patients. We report this case on account of the unusual skin presentation.

Soluble intracellular adhesion molecule-1 secreted by human umbilical cord blood-derived mesenchymal stem cell reduces amyloid-β plaques

Presently, co-culture of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) with BV2 microglia under amyloid-β42 (Aβ42) exposure induced a reduction of Aβ42 in the medium as well as an overexpression of the Aβ-degrading enzyme neprilysin (NEP) in microglia. Cytokine array examinations of co-cultured media revealed elevated release of soluble intracellular adhesion molecule-1 (sICAM-1) from hUCB-MSCs. Administration of human recombinant ICAM-1 in BV2 cells and wild-type mice brains induced NEP expression in time- and dose-dependent manners. In co-culturing with BV2 cells under Aβ42 exposure, knockdown of ICAM-1 expression on hUCB-MSCs by small interfering RNA (siRNA) abolished the induction of NEP in BV2 cells as well as reduction of added Aβ42 in the co-cultured media. By contrast, siRNA-mediated inhibition of the sICAM-1 receptor, lymphocyte function-associated antigen-1 (LFA-1), on BV2 cells reduced NEP expression by ICAM-1 exposure. When hUCB-MSCs were transplanted into the hippocampus of a 10-month-old transgenic mouse model of Alzheimer's disease for 10, 20, or 40 days, NEP expression was increased in the mice brains. Moreover, Aβ42 plaques in the hippocampus and other regions were decreased by active migration of hUCB-MSCs toward Aβ deposits. These data suggest that hUCB-MSC-derived sICAM-1 decreases Aβ plaques by inducing NEP expression in microglia through the sICAM-1/LFA-1 signaling pathway.

Correlation between the immature characteristics of umbilical cord blood-derived mesenchymal stem cells and engraftment of hematopoietic stem cells in NOD/SCID mice

Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSC) facilitate the engraftment of human (h) hematopoietic stem cells when transplanted simultaneously in animal and human studies. However, the type of MSCs that preferentially enhance the engraftment of HSCs is unknown. Recent studies have shown that MSCs derived from a single source are heterogeneous in terms of cell size, morphology, proliferation rate, and differentiation potential. This study was designed to investigate the properties of UCB-MSCs, which influence the engraftment of hHSCs in a NOD/SCID mouse model. We categorized MSCs as being the most effective (UCB-352 MSCs) or the least effective (UCB-156 MSCs) at promoting the homing and engraftment of HSCs, and compared the characteristics of these 2 MSC populations. We observed that the 2 populations showed differences in characteristics typical of immature MSCs, and related to proliferation potential. We showed that UCB-352 MSCs, which proliferate quickly, preferentially enhanced the engraftment of HSCs in NOD/SCID mice. In addition, we observed differences in the pattern of both PODXL and Oct4 expression, and in the levels of cytokines such as SDF-1 and SCF using flow cytometry and membrane arrays. The more effective UCB-352 MSCs expressed higher levels of PODXL and Oct4, which were associated with immaturity, than did the UCB-156 MSCs. Furthermore, UCB-352 cells secreted greater levels of SDF-1 and SCF, both of which are required for hematopoiesis. We propose that the proliferation potential of UCB-MSCs, coupled with their immature characteristics, may serve as a novel standard to promote the homing and engraftment of HSCs.

DNA mismatch repair related gene expression as potential biomarkers to assess cadmium exposure in Arabidopsis seedlings

In the current study, Arabidopsis seedlings were hydroponically grown on MS media containing cadmium (Cd) of 0-2.0 mg L(-1) for 60 h of treatment. Gene expression profiles were used to relate exposure to Cd with some altered biological responses and/or specific growth effects. RT-PCR analysis was used to quantitate mRNA expression for seven genes known to be involved in DNA mismatch repair (MMR) system and cell division. Results indicated that Cd concentrations of 0.25-2.0 mg L(-1) cause increased total soluble protein levels in shoots of Arabidopsis seedlings in an inverted U-shaped dose-response manner. Exposure to 0.25 and 0.5 mg L(-1) of Cd dramatically induced expression of four genes (i.e. proliferating cell nuclear antigen 2 (atPCNA 2), MutL1 homolog (atMLH1), MutS 2 homolog (atMSH2) and atMSH3) and five genes (i.e. atPCNA1,2, atMLH1 and atMSH2,7), respectively, in shoots of Arabidopsis seedlings; Exposure to 1.0 mg L(-1) of Cd significantly elevated expression of only two genes (atMSH6,7), but caused prominent inhibition in expression of three genes (atPCNA2, atMLH1 and atMSH3) in shoots of Arabidopsis seedlings. The expression alterations of the above genes were independent of any biological effects such as survival, fresh weight and chlorophyll level of shoots. However, shoots of Arabidopsis seedlings exposed to 2.0 mg L(-1) of Cd exhibited statistically prominent repression in expression of these seven genes, and showed incipient reduction of fresh weight and chlorophyll level. This research provides data concerning sensitivity of expression profiles of atMLH1, atMSH2,3,6,7 and atPCNA1,2 genes in Arabidopsis seedlings to Cd exposure, as well as the potential use of these gene expression patterns as representative molecular biomarkers indicative of Cd exposure and related biological effects.

Microbial community variation and functions to excess sludge reduction in a novel gravel contact oxidation reactor

Excess biomass produced within the degradation processes of organic pollutants is creating environmental challenges. The gravel contact oxidation reactor (GCOR) filled with crushed stone globular aggregates as carriers, has been demonstrated capable of reducing the excess sludge effectively in some pilot and small-scale engineering studies. In order to evaluate the variation and structure of the microbial community and their functions to excess sludge reduction in GCOR, a conventional activated sludge reactor (ASR) was studied as a comparison. The 16S rDNA library of the universal bacteria was constructed, Shannon's diversity index (H) and Species evenness (E) were calculated with distance-based operational taxonomic unit and richness (DOTUR) for microbial diversity. Real-time quantity PCR and optical microscope were used for absolute bacterial DNA concentration and eukarya identification, respectively. Meanwhile, the suspended solid index in GCOR and ASR was detected for assessing the excess sludge production. The results indicated that the most abundant bacteria in GCOR were those related to the beta-Proteobacteria group, then gamma-Proteobacteria and to Cytophaga-Flexibacter-Bacteriode (CFB). In the ASR samples major bacteria were in the closest match with gamma-Proteobacteria, then beta-Proteobacteria and CFB. Shannon's index (H) was higher (3.41) for diversity of bacteria extracted from the carrier samples in GCOR than that (2.71) from the sludge sample in ASR. Species evenness (E) for the isolates from GCOR and ASR samples was 0.97 and 0.96, respectively. Comparison of the universal bacteria population in GCOR and ASR shows that the total bacterial DNA concentration on the GCOR carriers were 8.98 x 10(5) microg/ microl, twice that in ASR of 4.67 x 10(5) microg/ microl under normal operation of two reactors. But the MLSS in GCOR was only 4.5mg/L, 25 times less than that in ASR of 115.4 mg/L. The most representative eukarya were protozoa both in GCOR (15 no. per 20 ml) and in ASR (15 no. per 20 ml); the next abundant group was attachment plants 10 no. per 20 ml in GCOR and 4 no. per 20 ml in ASR, respectively. Rotifers and copepoda belonging to metazoan were only present in GCOR (8 no. per 20 ml for both rotifers and copepoda). The microbial diversity and population difference both in the GCOR carriers and ASR sludge indicated that the diverse microbes, a large amount of biomass forming longer microbial food chains attached on the carriers may be the main functions for the excess sludge reduction in GCOR.

Risk assessment of cadmium-contaminated soil on plant DNA damage using RAPD and physiological indices

Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) 'fingerprinting' technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144-2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245 bp appeared almost for 10, 20 and 40 mg L(-1) Cd with 9 primers (one-four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil.

Cadmium stress alters gene expression of DNA mismatch repair related genes in Arabidopsis seedlings

Cadmium (Cd) is a non essential element, and is a widespread environmental pollutant. Exposure to Cd can result in a variety of adverse health effects in plant and humans. In the current study, Arabidopsis seedlings were used as a bio-indicator of Cd pollution. Seedlings were grown on MS media containing 0-6.0 mg L(-1) Cd for 18 days, and the gene expression patterns were used to link increased Cd exposure with progressive biological effects. Reduction of total soluble protein content in shoots of the Arabidopsis seedlings occurred with increase in Cd concentrations. For the gene expression patterns, seven genes known to be involved in cell division and DNA mismatch repair (MMR) system were investigated by semi-quantitative RT-PCR, and normalized using 18S rRNA gene expression. Expression of the proliferating cell nuclear antigen 2 (atPCNA 2), MutS 3 homolog (atMSH 3) and MutL1 homolog (atMLH1) genes in shoots of Arabidopsis was strongly induced by exposure to 0.75 mg L(-1) Cd, but were repressed by other Cd concentrations whereas exposure to 0.75-6 mg L(-1) of Cd resulted in a decreased expression of atPCNA1, atMSH 2, 6 and 7 genes independently of any observable biological effects, including survival, fresh weight and chlorophyll level of shoots. This work demonstrated that specific gene expression changes could serve as useful molecular biomarkers indicative of Cd exposure and related biological effects.

Decolorization of cotton pulp black liquor by pleurotus ostreatus in a bubble-column reactor

Decolorization of cotton pulp black liquor by Pleurotus ostreatus B1 in a bubble-column reactor (BCR) was studied. The optimal conditions for the running of BCR are 30 degrees C, pH 6.0, aeration rate 1.2 L min(-1), and mycelial age 7 days. Under the optimal conditions, the BCR was run for four cycles (each cycle, 12 days) and the same mycelial pellets were reused. The ultimate decolorization and COD removal rates are 76% and 80%, respectively.

Effects of tert-butyl acetate on maternal toxicity and embryo-fetal development in Sprague-Dawley rats

This study investigated the potential adverse effects of tert-butyl acetate (TBAc) on maternal toxicity and embryo-fetal development after maternal exposure of pregnant rats from gestational days 6 through 19. TBAc was administered to pregnant rats by gavage at 0, 400, 800, and 1,600 mg/kg/day. All dams were subjected to a Caesarean section on day 20 of gestation, and their fetuses were examined for any morphological abnormalities. At 1,600 mg/kg, maternal toxicity manifested as increases in the incidence of clinical signs and death, lower body weight gain and food intake, increases in the weights of adrenal glands and liver, and a decrease in thymus weight. Developmental toxicity included a decrease in fetal weight, an increase in the incidence of skeletal variation, and a delay in fetal ossification. At 800 mg/kg, only a minimal developmental toxicity, including an increase in the incidence of skeletal variation and a delay in fetal ossification, were observed. In contrast, no adverse maternal or developmental effects were observed at 400 mg/kg. These results show that a 14-day repeated oral dose of TBAc is embryotoxic at a maternally toxic dose (i.e., 1,600 mg/kg/day) and is minimally embryotoxic at a nonmaternally toxic dose (i.e., 800 mg/kg/day) in rats. However, no evidence for the teratogenicity of TBAc was noted in rats. It is concluded that the developmental findings observed in the present study are secondary effects to maternal toxicity. Under these experimental conditions, the no-observed-adverse-effect level of TBAc is considered to be 800 mg/kg/day for dams and 400 mg/kg/day for embryo-fetal development.

Ecological risk assessment using RAPD and distribution pattern of a rare and endangered species

Environmental and ecological risk assessment always provide useful evidence for characterisation and conservation of the rare and endangered species, e.g. seven-son flower (Heptacodium miconioides Rehd.). Seven-son flower is a deciduous arbor species, but endangered, with a restricted distribution in the subtropical forests of China. Genetic risk assessment of 56 samples of the flower from nine main populations in Zhejiang (China) was carried out by using the RAPD analysis. This was to study the ecological characteristics, spatial distribution and genetic features of the seven-son flower communities and establish a feasible conservation plan. Twenty-one primers screened from 50 yielded 119 RAPD bands with 72 polymorphic products and 60.50% of total bands. The genetic variation was found to be partitioned mainly among rather than within populations. Percentages of genetic diversity among populations were quantified by Shannon index and the Nei's gene diversity coefficient. AMOVA also demonstrated that these relict populations were highly differentiated. The high level of population variation observed is in contrast to that expected for a primarily outcrossed woody perennial plant, and suggests that there may be a degree of inbreeding. The dendrogram constructed from genetic distances through UPGMA method based on Nei's coefficients shows two groups among nine population clusters, which is further supported by a principle components analysis (PCA) of RAPD phenotypic data. The analysis showed that the biologic characteristics and habitat fragmentation were the reasons of the great genetic variation among populations. Some strategies of its genetic diversity conservation were proposed in the fragmented habitats based on its genetic structure and its biological characteristics in this study.

Environmental hazard analysis and effective remediation of highway seepage

Risk assessment and minimisation of environmental hazards are critical issues to consider in the geotechnical engineering projects. A case of highway pavement seepage induced by groundwater, at a locality along the section of Hua-Qing Highway of Guangdong Province, China, is presented for environmental hazard analysis and effective remediation. The environmental hazard analyses were based on in situ hydrogeologic investigation, rock-soil testing and integrated environmental understanding. The analyses indicate that the highway seepage was caused by elevation of groundwater hydraulic pressure in low permeable strata near the highway pavement, which was controlled by landform, hydrology, weather and road structure. The risk source of groundwater 'flooding' was the groundwater and surface water in the ring-like valley around Fenshui Village. A blind-ditch system for effective remediation of the pavement seepage hazard was proposed and successfully implemented by declining groundwater table near the highway based on the comprehensive assessment of various conditions. This geotechnical accident shows that the role of groundwater is an essential factor to consider in the geotechnical and environmental engineering studies and multidisciplinary effort for risk assessment of environmental hazards is important under current global climate change condition.

Impact assessment of cadmium contamination on rice (Oryza sativa L.) seedlings at molecular and population levels using multiple biomarkers

Assessment of environmental contamination on ecology (plant) at molecular and population levels is important in risk quantification and remediation study. Random amplified polymorphic DNA (RAPD) assay and related other fingerprinting techniques have been employed to detect the genotoxin-induced DNA damage and mutations. This research compared the effects occurring at molecular and population levels in rice seedlings exposed to cadmium (Cd) concentrations of 15-60 mg l(-1) for 8 days with quartz sand culture. Inhibition of root growth and increase of total soluble protein content in root tips of rice seedlings were observed with the increase of Cd concentration. For the RAPD analyses, 12 RAPD primers of 50-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 180 bands of 179-3056 bp in molecular size in the control root tips of rice seedlings. Results produced by these RAPD primers indicate that changes in RAPD profiles of root tips after Cd treatment include modifications in band intensity and gain or loss of bands by comparison with control. The effect of changes was dose-dependent. Genomic template stability compares favourably with the traditional indices such as root growth and soluble protein content. The DNA polymorphisms detected by RAPD analysis can be applied as a suitable biomarker assay for the detection of genotoxic effects of Cd contamination on plants.

Evaluation of developmental toxicity of amitraz in Sprague-Dawley rats

This study investigated the potential adverse effects of amitraz on the initiation and maintenance of pregnancy in Sprague-Dawley rats as well as its effects on embryo-fetal development after maternal exposure during the entire pregnancy period. Amitraz was administered to pregnant rats by gavage from days 1 to 19 of gestation at dose levels of 0, 3, 10, and 30 mg/kg/day. All dams underwent a caesarean section on day 20 of gestation and their fetuses were examined for any external, visceral, and skeletal abnormalities. At 30 mg/kg, maternal toxicity manifested as an increase in the incidence of abnormal clinical signs and a lower body weight gain and food intake. Developmental toxicity included an increase in the fetal death rate, a decrease in the litter size, and a reduction in the fetal body weight. In addition, there was an increase in the incidence of fetal external, visceral, and skeletal abnormalities. At 10 mg/kg, maternal toxicity observed included a decrease in the body weight gain and a decrease in food intake. In addition, minimal developmental toxicity, including a decrease in the fetal body weight, an increase in the visceral and skeletal aberrations, and a delay in fetal ossification. There were no signs of either maternal toxicity or developmental toxicity at 3 mg/kg. These results show that amitraz administered during the entire pregnancy period in rats is embryotoxic and teratogenic at the maternally toxic dose (i.e., 30 mg/kg/day) and is minimally embryotoxic at a minimally maternally toxic dose (i.e., 10 mg/kg/day). Under these experimental conditions, the no-observed-adverse-effect level of amitraz for both dams and embryo-fetal development is estimated to be 3 mg/kg/day.

The glass transition temperatures of sugar mixtures

We measured the glass transition temperatures of mono-, di-, and trisaccharide mixtures using differential scanning calorimeter (DSC) and analyzed these temperatures using the Gordon-Taylor equation. We found that the glass transition temperatures of monosaccharide-monosaccharide and disaccharide-disaccharide mixtures could be described by the conventional Gordon-Taylor equation. However, the glass transition temperatures of monosaccharide-disaccharide and monosaccharide-trisaccharide mixtures deviated from the conventional Gordon-Taylor equation and the amount of deviation in the monosaccharide-trisaccharide mixtures was larger than those in the monosaccharide-disaccharide mixtures. From these results, we conclude that the size and shape of the sugars play an important role in the glass transition temperature of the mixtures.

Electrical Relaxation of Bismuth Germanate Silicate Glasses

The frequency-dependent electrical data of the bismuth germanate silicate (BGSO) glasses have been discussed in the framework of the electric modulus representation and the power-law conductivity. The activation energies of the mean electric relaxation time and the direct current (dc) conductivity obtained by the complex modulus analysis show that the BGSO glasses satisfy the Barton, Nakajima, and Namikawa (BNN) relation. The proper relation between the exponent of the power-law conductivity and the stretched exponential of the modulus representation is shown. The temperature- and frequency-dependent characteristics of non-Debye behavior are discussed. The scaling properties of both the modulus M*(omega) and the alternating current (ac) conductivity sigma(omega) are examined.

Advanced tertiary treatment of municipal wastewater using raw and modified diatomite

Advanced technology for more efficient and effective wastewater treatment is always timely needed. The feasibility of using raw and modified diatomite for advanced treatment of secondary sewage effluents (SSE) was investigated in this study. Raw diatomite at a dosing rate of 300 mg/l showed a similar potential as activated carbon for removing most organic pollutants and toxic metals from SSE. Its performance was found poor in removal of arsenic and crop nutrient constituents (e.g. ammoniacal nitrogen and phosphate) and remained unsatisfactory even when the dosing rate increased up to 500 mg/l. Where modified diatomite was in lieu of raw diatomite, the removal efficiency for all target constituents was improved by 20-50%. At the dosing rate of 150 mg/l, modified diatomite enabled the post-treated effluents to satisfy the discharge consents, with the levels of all target constituents below the regulatory limits. Modified diatomite has advantages over raw diatomite in improving removal efficiency and reducing the dosing rate required for satisfactory treatment of SSE. It is concluded that modified diatomite is much more effective and efficient than raw diatomite, as an alternative to activated carbon, for economic treatment of SSE.

DNA changes in barley (Hordeum vulgare) seedlings induced by cadmium pollution using RAPD analysis

In recent years, several plant species have been used as bioindicators, and several tests have been developed to evaluate the toxicity of environmental contaminants on vegetal organisms. In this study, barley (Hordeum vulgare L) seedling was used as bioindicator of cadmium (Cd) pollution in the range of 30-120 mgl(-1). Inhibition of root growth and reduction of total soluble protein content in root tips of barley seedlings were observed with the increase of Cd concentrations. The changes occurring in random amplified polymorphic DNA (RAPD) profiles of root tips following Cd treatment included variation in band intensity, loss of normal bands and appearance of new bands compared with the normal seedlings. Additionally, we found that the effect of changes was dose-dependent. These results indicated that genomic template stability (a qualitative measure reflecting changes in RAPD profiles) was significantly affected at the above Cd concentration. Thus, DNA polymorphisms detected by RAPD analysis could be used as an investigation tool for environmental toxicology and as a useful biomarker assay for the detection of genotoxic effects of Cd pollution on plants.

Genetic polymorphism of cytochrome P450 2C19 in healthy Malaysian subjects

AIMS

Impaired S-mephenytoin 4'-hydroxylation is a well-described genetic polymorphism affecting drug metabolism in humans. Although ethnic differences in its distribution of polymorphism has been described, it is not known whether there is an ethnic heterogeneity of the structure and expression of the CYP2C19 enzyme in the Malaysian population.

METHODS

Study subjects were 142 healthy, unrelated Malaysians aged 18-29 years. Baseline omeprazole and 2-h postingestion omeprazole and 5'-hydroxyomeprazole concentrations were measured for CYP2C19 phenotype determination. Identification of CYP2C19 genotypes was performed with the use of polymerase chain reaction.

RESULTS

Phenotyping of CYP2C19 revealed that the prevalence of poor metabolizers (PMs) in the Malaysian population was 14.1%, whereas prevalence of PMs in genotyping was 12.6%. The PM genotypic prevalence rate was 5.6% in Malays, 19.1% in Chinese and 10.0% in Indian subjects. There were significant differences in PM genotypic prevalence rates among the three primary ethnic groups (P < or = 0.05).

CONCLUSIONS

Phenotyping and genotyping revealed significant differences in the prevalence rates among the three ethnic groups in Malaysia, with Chinese recording highest prevalence.

Root growth inhibition and induction of DNA damage in soybean (Glycine max) by chlorobenzenes in contaminated soil

The cytotoxic and genotoxic effects of 1,2,4-trichlorobenzene (TCB), chlorobenzene (CB), and hexachlorobenzene (HCB) on root growth and DNA strand breakage damage of soybean nuclei in the test soil were studied using the comet assay. Results indicated that the root growth was significantly inhibited, and DNA strand breaks and the comet tail in the root tip nuclei were both induced after 48 h exposure with TCB concentrations of 50, 100, 200, 300 microg g(-1) in the soil. DNA strand breakage was more sensitive to the TCB than the root growth. There was a significant dose-response relationship between the TCB exposure and DNA strand breakage in the soybean nuclei. Thus it is possible for DNA strand breakage to be used as a biomarker of soybean exposed to TCB contamination. Significant cytotoxic threshold concentration of the TCB exposure on the root growth inhibition was determined as 61 microg g(-1) in the soil. The toxicity of 100-1,000 microg g(-1) CB and HCB to the soybean seedlings in the soil were not observed after 48 h or longer exposure.

Phytodegradation of extra heavy oil-based drill cuttings using mature reed wetland: an in situ pilot study

Environmental contamination caused by extra heavy oil-based drill cuttings (DCs) is a major problem in the Liaohe Oilfield, northeastern China. To study the potential effectiveness of the mature reed wetland in removing extra heavy oil contained in drill cuttings, biodegradation of extra heavy oils and study of the effects on soil property and ecophysiological and quality indices of reeds were carried out in a 2-year in situ pilot experiment. In the wetland, four reed beds were used to treat drill cuttings in various loadings: 0 (control), 5, 20, and 40 kg/m(2), corresponding to 150, 600, and 1200 g/m(2) extra heavy oil hydrocarbons (HCs). The obtained results demonstrate that the mature reed wetland was effective at degrading extra heavy oils without extra fertilization. Removal efficiencies of reed bed 2 in the 0- to 80-cm soil profile increased with time, from 90.1% (first harvest season) to 95.8% (second harvest season). After 2 years, only 4.2% of the initial hydrocarbons residual was retained in the surface soil. There was no apparent adverse effects on the surface soil property during degradation of extra heavy oils and, actually, the deeper soil property and reed quality indices were improved at the end of the experiment. Phytotoxicity, resulting in reduction of reed yield, was observed in the most heavily treated beds in the first year. However, long-term reed yield recovered robustly. During the 2-year period, reed height and leaf number were slightly inhibited.