bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of DNA damage by cadmium and interplay of antioxidant enzymes and agents
Authors: Badisa Veera L. D. , Latinwo Lekan M. , Odewumi Caroline O. , Ikediobi Christopher O. , Badisa Ramesh B. , Ayuk‐Takem Lambert T. , Nwoga Jude , West John 
Published: March 2007

AbstractCadmium is an environmental toxicant, which causes cancer in different organs. It was found that it damages DNA in the various tissues and cultured cell lines. To investigate the mechanism of DNA damage, we have studied the effect of cadmium‐induced DNA damage in plasmid pBR322 DNA, and the possible ameliorative effects of antioxidative agents under in vitro conditions. It was observed that cadmium alone did not cause DNA damage. However, it caused DNA damage in the presence of hydrogen peroxide, in a dose dependent manner, because of production of hydroxyl radicals. Findings from this study show the conversion of covalently closed circular double‐stranded pBR 322 DNA to the open circular and linear forms of DNA when treated with 10 μM cadmium and various concentrations of H2O2. The conversion was due to nicking in DNA strands. The observed rate of DNA strand breakage was dependent on H2O2 concentration, temperature, and time. Metallothionein I failed to prevent cadmium‐induced DNA nicking in the presence of H2O2. Of the two antioxidant enzymes (catalase and superoxide dismutase) studied, only catalase conferred significant (50–60%) protection. EDTA and DMSO exhibited protection similar to catalase, while mannitol showed only about 20% protection against DNA damage. Ethyl alcohol failed to ameliorate cadmium‐induced DNA strands break. From this study, it is plausible to infer that cadmium in the presence of hydrogen peroxide causes DNA damage probably by the formation of hydroxyl ions. These results may indicate that cadmium in vivo could play a major role in the DNA damage induced by oxidative stress. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 144–151, 2007.
Relationship between clinical features and blood levels of pentachlorodibenzofuran in patients with Yusho
Authors: Imamura Tomoaki , Kanagawa Yoshiyuki , Matsumoto Shinya , Tajima Bunichi , Uenotsuchi Takeshi , Shibata Satoko , Furue Masutaka 
Published: March 2007

AbstractBackground: Yusho is a form of food poisoning that occurred in 1968, as a result of consuming rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins such as polychlorinated dibenzofurans (PCDFs). The victims of Yusho suffered from various dermatological, ophthalmological, and mucosal symptoms in addition to general fatigue, weight loss, anorexia, headache, paresthesia of the extremities, abdominal pain, cough and sputa, dysmenorrhea, and growth retardation in infants and children. We measured the blood levels of dioxins in the annual medical check‐up of Yusho patients from 2001 to 2003. Purpose: To analyze the relationship between the concentrations of PCDFs/PCBs and the subjective/objective/laboratory findings of patients with Yusho. We also compared the present clinical findings with those collected in 1988. Results and discussion: The mean blood level of 2,3,4,7,8‐pentachlorodibenzofuran (PeCDF) in 359 patients with Yusho was 177.50 pg/g lipids, which was much higher than that of normal controls (15.2 ± 8.9 pg/g lipids). The blood levels of PeCDF were significantly correlated with total PCB levels, hexachlorobiphenyl levels, urinary sugar, 2‐h erythrocyte sedimentation rate, thymol turbidity test, and sodium levels. A significant correlation was also noted with dermatological findings (acneform eruption and comedones), mucosal findings (oral pigmentation), constipation, numbness in the extremities, body weight loss, and abnormal abdominal ultrasonography. The incidence and severity of most of the dermatological and ophthalmological symptoms decreased from 1988 to 2001–2003. In conclusion, high amounts of PCBs and PeCDF are still present in a number of patients with Yusho. The patients still suffer from various mucocutaneous and subjective symptoms. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 124–131, 2007.
In vitro synthesis of 1,N6‐etheno‐2′‐deoxyadenosine and 1,N2‐etheno‐2′‐deoxyguanosine by 2,4‐dinitrophenol and 1,3‐dinitropyrene in presence of a bacterial nitroreductase
Authors: Chiron Serge , Barbati Stéphane , De Méo Michel , Botta Alain 
Published: March 2007

AbstractThe formation of covalent nitro‐PAH DNA adducts and nitro‐PAH mediated oxidative lesions are two possible mechanisms for the initiation of nitro‐PAH carcinogenesis. Sixty‐minute incubation of 1,3‐dinitropyrene (100 μM) or 1,4‐dinitrophenol (100 μM) with a mixture of 150 μM NADH, 0.5 units of E. coli nitroreductase, 100 μM linoleic acid, 0.5 mM ferrous iron, and 100 μM 2′‐deoxyadenosine (2′‐dA) or 100 μM 2′‐deoxyguanosine (2′‐dG) were analyzed by liquid chromatography multistage mass spectrometry. Mixtures of 1,N6‐etheno‐2′‐deoxyadenosine (εdA) plus 4‐oxo‐2‐nonenal (4‐ONE) and 1,N2‐etheno‐2′‐deoxyguanosine (εdG) plus 4‐ONE could be detected from 2′‐dA and 2′‐dG, respectively. Addition of 2% propanol inhibited the formation of etheno adducts. Analyses of disappearance kinetics of dA and dG showed that dG was more rapidly eliminated than does dA (t[1/2] = 23.3 min and 98.3 min for dG and dA, respectively). Curves of formation kinetics revealed that the peak of εdG was at 55.6 min while that of εdA was at 186.9 min. These peaks represented 1.43% and 1.25% of the original dG and dA, respectively. In both cases, the peaks were followed by rapid degradations of etheno adducts. The results, obtained in this system, do not allow any extrapolation to realistic cellular responses; nevertheless, these data questioned the validity of the use of unsubstituted etheno adducts as reliable oxidative stress and nitro‐PAH exposure biomarkers. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 222–227, 2007.
Testing estrogenicity of known and novel (xeno‐)estrogens in the MolDarT using developing zebrafish (Danio rerio)
Authors: Muncke Jane , Junghans Marion , Eggen Rik I. L. 
Published: March 2007

AbstractThe MolDarT is a novel short‐term assay for testing mechanism‐based molecular effects in developing zebrafish embryos. The objective of this study was to evaluate the inducibility of vitellogenin1 mRNA (Vtg1) by the estrogenically active compounds 17β‐Estradiol (E2), 17α‐Ethinylestradiol (EE2), Nonylphenol (NP), Bisphenol A (BPA), Cyproconazol, and the suspected xeno‐estrogen Atrazin in the MolDarT. Freshly fertilized zebrafish eggs were exposed semistatically for 120 h. Using reverse transcription real‐time PCR, the relative abundance of Vtg1 was measured. For EE2 a dose‐response relationship was established with EC50 = 60.7 ng/L (205 pM). Induction of Vtg1 was significant at concentrations of 84 pM EE2 (25 ng EE2/L) and above, 10 nM E2 (2.7 μg E2/L), 100 nM E2 (27 μg E2/L), 10 μM BPA (2280 μg BPA/L), and 15 μM BPA (3420 μg BPA/L). At NP concentrations of 0.75 μM (165 μg NP/L) and 1.5 μM (330 μg NP/L) Vtg1 was significantly down‐regulated. Both atrazine and cyproconazol showed no effect on relative Vtg1 abundance. With this study we further characterize the MolDarT assay and show its applicability for effect screening of compounds. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 185–193, 2007.
Short‐term effects of Quirlan® (chlorfenvinphos) on the behavior and acetylcholinesterase activity of Gambusia holbrooki
Authors: Sismeiro‐Vivas J. , Abrantes N. , Pereira J. L. , Castro B. B. , Gonçalves F. 
Published: March 2007

AbstractChlorfenvinphos is a widespread organophosphorous (OP) insecticide and it is a reported hazardous chemical for aquatic nontarget organisms. This study intended to evaluate the effects of sublethal concentrations of Quirlan® (commercial formulation of chlorfenvinphos) on several behavioral parameters of the mosquitofish, Gambusia holbrooki. The insecticide showed high toxicity to G. holbrooki by significantly impairing all the behavioral responses (location in the test vessel, activity/excitability, swimming, and feeding), exhibiting a time‐dependent pattern. Behavioral EC50s, after a 96‐h exposure, ranged from 5.2 to 9.0 μg L−1. As OP pesticides are acutely neurotoxic, acetylcholinesterase (AChE) activity was also selected for use as a biomarker in this study for the establishment of a relationship with the observed behavior abnormalities. A strong inhibition of AChE was observed in fish exposed to chlorfenvinphos (IC50 = 3.55 μg L−1). Behavioral impairment was registered in fish with >40% AChE inhibition levels, while mortality was only observable in fish exhibiting AChE inhibition levels >80%. Additionally, significant correlations were found between behavioral impairment and AChE inhibition, suggesting a mechanistic link. These results show the usefulness of integrating biochemical and individual endpoints in a small‐sized model species, and confirm a potential hazard of chlorfenvinphos to nontarget aquatic organisms. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 194–202, 2007.
Oxidative stress in the clam Ruditapes decussatus (Linnaeus, 1758) in relation to polycyclic aromatic hydrocarbon body burden
Authors: Barreira Luísa A. , Mudge Stephen M. , Bebianno Maria J. 
Published: March 2007

AbstractSeasonal variation of antioxidant enzymes activities (superoxide dismutase, catalase, and glutathione peroxidases) and lipid peroxidation (LPO) were studied in the clam Ruditapes decussatus in relation to body burdens of polycyclic aromatic hydrocarbons (PAHs). Clams were sampled in eight sites from the Ria Formosa lagoon. PAH concentrations were seasonally rather than spatially dependent, being higher in summer (August). Antioxidant enzymes activities and LPO levels in the clam digestive gland were also seasonally dependent. Antioxidant enzymes presented distinct seasonal variations: Mit SOD (superoxide dismutase activity measured in the mitochondrial fraction) was induced in the summer and down‐regulated in winter and spring, while Cyt SOD activity (measured in the cytosolic fraction) was highest in autumn and lower in the summer. Neither Mit nor Cyt SOD were related to the clam PAH body burden, suggesting that cells are using other antioxidant systems to eliminate oxyradicals. Catalase (CAT), however, was induced in spring and down‐regulated in summer, the inverse of the PAH concentrations in clam tissues. CAT induction in spring appears to be related to the excess of oxyradicals arising from the metabolic activity associated with the reproductive cycle. Conversely, the decrease in CAT activity in the summer may be related to the high water temperatures reached in the Ria Formosa (up to 30 °C). Glutathione peroxidases (total fraction ‐ T‐GPx and dependent on selenium ‐ Se‐GPx) presented a similar seasonal pattern, and were negatively related to PAH concentrations, which may indicate a precarious state of the clams, associated with PAH toxicity. Similarly, LPO was also inversely correlated to the PAH concentrations indicating that increases in PAH concentrations were not causing membrane oxidative damage in R. decussatus digestive gland. The results suggest that antioxidant enzymes in R. decussatus digestive gland are strongly affected by seasonal factors stressing the need of other experiments to clarify the PAHs effect on this clam species. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 203–221, 2007.
Measurements of K‐shell x‐ray production cross sections and K to L and M‐shell radiative vacancy transfer probabilities for Nd, Eu, Gd, Dy and Ho at excitation with 59.5 keV photons in an external magnetic field
Authors: Demir Demet , Şahin Yusuf 
Published: March 2007

AbstractThe effect of the ± 0.75 T external magnetic field on the Kα1, Kα2, Kβ′1 and Kβ′2 x‐ray production cross sections and radiative vacancy transfer probabilities from K‐shell to L2 and L3 subshells and M‐shell for ferromagnetic Nd, Gd and Dy and paramagnetic Eu and Ho have been investigated, using the 59.5 keV incident photons. K‐shell fluorescence yields and K x‐ray intensity ratios for these elements have been determined in the external magnetic field also. The K x‐rays from different targets were detected using a high‐resolution Si(Li) semiconductor detector. For B = 0, the present experimental results were compared with the experimental and theoretical data in the literature. The results show that K‐shell fluorescence parameters such as photoionization cross section, fluorescence yield, radiation rates, vacancy transfer probabilities and spectral linewidth can change owing to the applied magnetic field. Copyright © 2007 John Wiley & Sons, Ltd.
Delayed accumulation of the yeast G1 cyclins Cln1 and Cln2 and the F‐box protein Grr1 in response to glucose
Authors: Fey Julien P. , Lanker Stefan 
Published: March 2007

AbstractThe ability to integrate nutrient availability into cell cycle regulation is critical for the viability of organisms. The Saccharomyces cerevisiae ubiquitin ligase SCF(Grr1) regulates the stability of several proteins that participate in cell division or nutrient sensing. Two of its targets, the cyclins Cln1 and Cln2, accumulate in the presence of glucose. When glucose is added to cells growing asynchronously, we show that the accumulation of the cyclins is a very slow response. We report that the F‐box protein Grr1 also accumulates at higher levels in the presence of glucose, and that the response to glucose follows a delayed pattern strikingly similar to that described for Cln1 and Cln2. A model for the regulation of F‐box proteins predicts that substrate accumulation could stabilize Grr1. While we found that Grr1 is more stable in cells growing with glucose, we show that the delayed responses to glucose occur independently: Grr1 accumulates in the absence of the cyclins, and vice versa. Thus, our results indicate that this model might not apply to the cyclins and Grr1. Glucose is known to strengthen the interaction of Grr1 with Skp1 in the SCF complex. We hypothesize that glucose could promote the accumulation of Grr1 and its assembly into a SCF complex as a feedback regulation that helps compensate for higher cyclins levels. Copyright © 2007 John Wiley & Sons, Ltd.
Comparative study of additive basal area of conifers in forest ecosystems along elevational gradients
Authors: Aiba Shin‐ichiro , Hanya Goro , Tsujino Riyou , Takyu Masaaki , Seino Tatsuyuki , Kimura Katsuhiko , Kitayama Kanehiro 
Published: March 2007

AbstractWe examined the basal area of two life forms (conifers vs. broadleaf trees) along elevational gradients on Yakushima Island, Japan and on two series of geological substrate on Mount Kinabalu, Borneo. On Yakushima, total stand basal area abruptly increased from 700 to 1,050 m in accordance with the high dominance of conifers, indicating the presence of additive basal area of conifers in conifer–broadleaf mixed forests at higher elevations (1,050–1,300 m). Along two substrate series on Kinabalu, some forests at higher elevations (1,860–3,080 m) showed relatively high dominance of conifers, but conifer basal area did not appear to be additive. Conifers were emergents above the canopy of broadleaf trees in mixed forests on Yakushima, but two life forms usually coexisted in the single‐story canopy in mixed forests on Kinabalu. Litterfall rate as a surrogate of productivity decreased with decreasing temperature along elevation on both the sites, but the rate of decrease was slower on Yakushima, where mixed forests at higher elevations showed relatively high rates. Thus, we suggest that additive basal area of conifers was linked to their emergent status, and that it enhanced productivity by complementary use of light by two life forms that occupy different stories. On Yakushima, typhoons are a major disturbance, but do not severely limit the height growth of conifers, allowing the development of two‐story mixed forests. On Kinabalu, a major disturbance is El Niño‐driven drought, and hydraulic limitation to tree height may explain the non‐additive and non‐emergent nature of conifers.
Synthesis and Characterization of Multifunctional Surfactants in Oil‐Field Protection Applications
Authors: Negm Nabel A. , Aiad Ismail A. 
Published: March 2007

AbstractA series of cationic surfactants was prepared using economical raw materials. The chemical structures of the prepared compounds were confirmed using elemental analysis, FTIR and 1H‐NMR spectra, and melting point determination. The synthesized surfactants were evaluated as oil‐field protective additives. In this regard, several surface properties of the synthesized surfactants were studied including surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area. The results obtained from the surface activity measurements were correlated to their chemical structures. The emulsification power measurements for solutions of these surfactants showed their low emulsifying tendency towards paraffin and crude oil. The synthesized surfactants also exhibited high biocidal activity towards gram‐positive and gram‐negative bacteria and fungi. This activity was increased by increasing the hydrophobic chain length. The corrosion inhibition measurement of these surfactants for mild steel alloys in acidic media using a weight loss technique showed good protection of mild steel alloys against acidic environments. These properties qualify the synthesized compounds as economical oil‐field protective additives.
Genetic and epigenetic alterations as biomarkers for cancer detection, diagnosis and prognosis
Authors: Herceg Zdenko , Hainaut Pierre 
Published: March 2007

AbstractThe development of cancer is driven by the accumulation of scores of alterations affecting the structure and function of the genome. Equally important in this process are genetic alterations and epigenetic changes. Whereas the former disrupt normal patterns of gene expression, sometimes leading to the expression of abnormal, constitutively active proteins, the latter deregulate the mechanisms such as transcriptional control leading to the inappropriate silencing or activation of cancer‐associated genes. Both types of changes are inheritable at the cellular level, thus contributing to the clonal expansion of cancer cells. In this review, we summarize current knowledge on how genetic alterations in oncogenes or tumour suppressor genes, as well as epigenetic changes, can be exploited in the clinics as biomarkers for cancer detection, diagnosis and prognosis. We propose a rationale for identifying alterations that may have a functional impact within a background of “passenger” alterations that may occur solely as the consequence of deregulated genetic and epigenetic stability. Such functional alterations may represent candidates for targeted therapeutic approaches.
Perceived body size and desire for thinness of young Japanese women: a population-based survey
Authors: Hayashi F. , Takimoto H. , Yoshita K. , Yoshiike N. 
Published: March 2007

The present study describes findings in relation to perceived body size and ‘desire for thinness’ by age and residential areas (‘metropolitan areas’, ‘large cities’, ‘small cities’ and ‘towns’) among young Japanese women. Data on 1731 non-pregnant, non-lactating women aged 15–39 years from the 1998 National Nutrition Survey of Japan were used. Current body size was evaluated by BMI percentiles (lean, < 5th; underweight, 5th ≤ BMI < 25th; normal, 25th ≤ BMI < 75th; overweight, 75th ≤ BMI < 95th; obese, ≥ 95th), calculated for 5-year age groups. Perceived body size was obtained by self-report. We defined ‘overestimation’ as non-overweight, non-obese women who perceived themselves as being ‘overweight’ or ‘obese’. Desired body size was evaluated by applying the desired BMI to these cut-off points. Of all the women, 48·4 % perceived themselves as being ‘overweight’ or ‘obese’, and 43·7 % desired a ‘lean’ or ‘underweight’ body size. Adjusted for the current BMI, the OR for ‘overestimation’ calculated by a logistic regression model was significantly elevated in the 15–19-year age group (OR 2·79; 95 % CI 1·76, 4·43), compared with the 25–29-year age group. The OR for ‘desire for thinness’ was significantly high in the 35–39-year age group (OR 2·74; 95 % CI 1·93, 3·89) and the 15–19-year age group (OR 2·26; 95 % CI 1·57, 3·24). Women living in metropolitan areas had higher OR for ‘desire for thinness’ (but not for ‘overestimation’) than did women in towns (OR 1·47; 95 % CI 1·05, 2·07). The findings suggest the nature of excessive weight concerns of young women in Japan; thus efforts to control such health-risk behaviours at a national level are urgent.
Conventional and real-time polymerase chain reaction assessment of the fate of transgenic DNA in sheep fed Roundup Ready®rapeseed meal
Authors: Alexander Trevor W. , Reuter Tim , Okine Erasmus , Sharma Ranjana , McAllister Tim A. 
Published: March 2007

Conventional and real-time PCR were used to detect transgenic DNA in digesta, faeces and blood collected from six ruminally and duodenally cannulated sheep fed forage-based (F) or concentrate-based (C) diets containing 15 % Roundup Ready®(RR) rapeseed meal (n3). The sheep were adapted for 14 d to F or C diets containing non-GM rapeseed, then fed the RR diets for 11 d. On day 12, they were switched back to non-GM diets for a further 11 d. Ruminal and duodenal fluids (RF, DF) and faecal samples were collected at 3 or 4 h intervals over the 4 d immediately following the last feeding of GM diets. DNA was isolated from whole RF and DF, from the cell-free supernatant fraction, and from culture fermentation liquid. Blood was collected on days 1, 5 and 9 of feeding the RR rapeseed meal. The 1363 bp 5-enolpyruvylshikimate-3-phosphate synthase transgene (epsps) was quantifiable in whole RF and DF for up to 13 h, and a 108 bpepspsfragment for up to 29 h. Transgenic DNA was not detectable in faeces or blood, or in microbial DNA. Diet type (Fv.C) did not affect (P>0·05) the quantity of transgenic DNA in digesta. More (P < 0·05) transgenic DNA was detected in RF than in DF, but there was an interaction (P < 0·05) between sample type and collection time. In supernatant fractions from RF and DF, three different fragments of transgenic DNA ranging in size from 62 to 420 bp were not amplifiable.