Reproductive toxicity of ethylene glycol monoethyl ether in Aldh2 knockout mice

Ethylene glycol monoethyl ether (EGEE) can cause damage to testes and sperm, and its metabolites are believed to play an important role in its toxicity. Aldehyde dehydrogenase 2 (ALDH2) is involved in the metabolism of this chemical. To investigate whether and how the enzyme affects the toxicity of EGEE, we conducted experiments comparing Aldh2 knockout mice with wild-type mice. Administration of EGEE at 100 and 600 mg/kg/day for one week did not induce any significant change in the weight and body weight ratios of testes, prostate and epididymides in either Aldh2 knockout or wild-type mice. However, motion of sperm from the spermaduct, as analyzed with a Hamilton-Thorne Sperm analyzer, was slightly decreased in the low dose group, and significantly lower in the high dose group; and the percentage of progressive sperm was also reduced in the two EGEE groups. This effect of EGEE treatment was observed in the wild-type, but not in the Aldh2 knockout mice. Sperm motion from the cauda epididymides was not affected. On the other hand, the concentration of ethoxyacetic acid, a metabolite of EGEE, in 24 h pooled urine of EGEE-treated Aldh2 knockout mice was not significantly lower than that of the wild-type mice on most days of urine sampling. These results suggest that inactivation of the ALDH2 enzyme due to gene mutation may be linked to differences in the susceptibility to EGEE-induced sperm toxicity.

Minimum conflict individual haplotyping from SNP fragments and related genotype

The Minimum Error Correction (MEC) is an important model for haplotype reconstruction from SNP fragments. However, this model is effective only when the error rate of SNP fragments is low. In this paper, we propose a new computational model called Minimum Conflict Individual Haplotyping (MCIH) as an extension to MEC. In contrast to the conventional approaches, the new model employs SNP fragment information and also related genotype information, thereby a high accurate inference can be expected. We first prove the MCIH problem to be NP-hard. To evaluate the practicality of the new model we design an exact algorithm (a dynamic programming procedure) to implement MCIH on a special data structure. The numerical experience indicates that it is fairly effective to use MCIH at the cost of related genotype information, especially in the case of SNP fragments with a high error rate. Moreover, we present a feed-forward neural network algorithm to solve MCIH for general data structure and large size instances. Numerical results on real biological data and simulation data show that the algorithm works well and MCIH is a potential alternative in individual haplotyping.

Inhibitory effect of ethylene glycol monoethyl ether on rat sperm motion

Ethylene glycol monoethyl ether (EGEE) is known to have testicular toxicity. To elucidate whether EGEE has any effect on sperm motion, especially in the case of short time exposure, we conducted a series of in vivo experiments with rats, as well as an in vitro study with rat sperm. Sperm from cauda epididymides and spermaducts was analyzed for the change in motion with a Hamilton-Thorne Sperm analyzer. Administration of EGEE at 600 mg/kg/d for five weeks significantly decreased total and progressive motility of sperm to 15-30% of controls, in both the cauda epididymis and the spermaduct. The time-course experiment using a single dose of 1,000 mg/kg showed that damage to sperm motion was evident at 12-24 h after EGEE administration. Addition of EGEE to the medium of sperm had no effect on its motion, but the metabolite ethoxyacetic acid showed a significant inhibitory effect. These results suggest that besides its toxicity to spermatogenesis, the metabolite of EGEE may also directly affect the motion of mature sperm.

Effects of in utero and lactational exposure to di(2-ethylhexyl)phthalate on somatic and physical development in rat offspring

Di(2-ethylhexyl)phthalate (DEHP) has been reported to act as an antiandrogen and to affect the reproductive organs and accessory genital glands. Thus, to assess the reproductive toxicity of DEHP it is important to examine both its adverse effects on the development of offspring following maternal exposure and its effects on sexual function and fertility. In the present study, we examined whether in utero and lactational exposure to DEHP affects postnatal somatic growth of offspring in the rat. Pregnant females were orally administered various doses of DEHP (0, 25, 100 or 400 mg/kg body weight/day) from gestational day (GD) 6 through postnatal day (PND) 20. There were no significant changes in body weight, body length, tail length, or the weight of individual organs between the control and DEHP-treated groups. Somatic hormonal parameters were the same for all DEHP doses. These findings suggest that in utero and lactational exposure to various concentrations of DEHP has very little effect on postnatal development or endocrine and physical status of male and female rat offspring under the experimental conditions of the present study.

Musculoskeletal disorders and their after-effects among health professionals in Beijing

Although musculoskeletal disorders (MSD) represent an important occupational issue worldwide, surprisingly few investigations have been conducted among white-collar workers in Mainland China. The current study examined MSD and their after-effects among 334 health professionals in Beijing, by means of an anonymous questionnaire (response rate: 99.4%). Of the respondents, 92.2% reported an MSD occurring in the previous 12 months, with the neck (72.2%), shoulder and lower back (59.9% each) being the most commonly affected body sites. Fifty-six percent of all MSD had persisted > 24 hours, 23.0% had interfered with their work ability and 15.9% required medical treatment. MSD of the hand/wrist and MSD of the shoulders were the most likely to last > 24 hours. MSD of the lower back, upper legs or hand/wrist were all associated with a reduction of work ability. Medical treatment was more likely to have been sought for MSD of the lower back or knees, when compared to other body sites. Females were five times more likely to report an MSD at any body site, while tobacco smokers were three times more likely to have sought medical treatment for an MSD. Overall, this study suggests that MSD are becoming an increasingly important cause of functional disability among white-collar workers in China. As some significant correlations were found during statistical analysis, further research should now investigate the complicity of various factors on MSD development within this emerging Chinese demographic.

Effects of perinatal exposure to bisphenol A on brain neurotransmitters in female rat offspring

Pregnant Sprague-Dawley (CD IGS) rats were orally administered doses of bisphenol A (BPA) at 4, 40, and 400 mg/kg, from gestation days 6 to postnatal day 20. Neurotransmitters such as dopamine (DA) and serotonin (5HT) were extracted from the brains of dams and female offspring, and measured using liquid chromatography. BPA at 400 mg/kg was toxic and dosed rats died. At 3 wk after birth, brain levels of 3,4-dihydroxyphenylacetic acid (DOPAC, a DA metabolite), homovanillic acid (HVA, a DA metabolite), 5HT, 5-hydroxyindoleacetic acid (5HIAA, a 5HT metabolite) in female offspring were increased and the HVA/DA ratio was high in some brain areas of BPA-treated groups as compared with controls. At the age of 6 wk, levels of choline (Ch) in BPA-treated groups at 4 and 40 mg/kg were higher than control in all of eight brain areas. No changes were observed in acetylcholine (ACh) contents. In 9-wk-old offspring, changes in monoamines and metabolites were scattered and not great. At 3 wk after delivery, levels of 5HIAA in some brain areas of dams treated with BPA were higher than in control dams. Dose dependent increases in HVA and the HVA/DA ratio of the occipital cortex, and in the HVA/DA ratio of the frontal cortex were observed. The turnover of DA and 5HT was accelerated in 3-wk-old offspring and dams. BPA possesses very weak estrogenic activity. Changes in cerebral neurotransmitters observed in offspring and dams in this study may have been related to the estrogenic activity of BPA. However, further investigation is needed to examine the contribution of hormonal activity to such neurotransmitter changes.

Needlestick and sharps injuries among nurses in a tropical Australian hospital

Although needlestick and sharps injuries (NSI) represent a major hazard in nursing practice, most studies rely on officially reported data and none have yet been undertaken in tropical environments. Therefore, we conducted a cross-sectional NSI survey targeting all nurses within a tropical Australian hospital, regardless of whether they had experienced an NSI or not. Our overall response rate was 76.7%. A total of 39 nurses reported 43 NSI events in the previous 12 months. The most common causative device was a normal syringe needle, followed by insulin syringe needles, i.v. needles or kits and blood collection needles. Half of the nurses' NSI events occurred beside the patient's bed: drawing up medication was the most common reason. Nurses working in the maternity/neonatal wards were only 0.3 times as likely to have experienced an NSI as their counterparts in the medical or surgical wards. Overall, our study has shown that NSI events represent an important workplace issue for tropical Australian nurses. Their actual rate might also be higher than official reports suggest.

Sol-gel fabrication and photoluminescence properties of SiO2 @ Gd2O3:Eu3+ core-shell particles

A uniform nanolayer of europium-doped Gd2O3 was coated on the surface of preformed submicron silica spheres by a Pechini sol-gel process. The resulted SiO2 @ Gd2O3:Eu3+ core-shell structured phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays. The XRD results show that the Gd2O3:Eu3+ layers start to crystallize on the SiO2 spheres after annealing at 400 degrees C and the crystallinity increases with raising the annealing temperature. The core-shell phosphors possess perfect spherical shape with narrow size distribution (average size: 640 nm) and non-agglomeration. The thickness of the Gd2O3:Eu3+ shells on the SiO2 cores can be adjusted by changing the deposition cycles (70 nm for three deposition cycles). Under short UV excitation, the obtained SiO2@Gd2O3:Eu3+ particles show a strong red emission with 5D0-7F2 (610 nm) of Eu3+ as the most prominent group. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

Tobacco smoking habits among a cross-section of rural physicians in China

OBJECTIVE

To investigate the prevalence and distribution of tobacco smoking among rural Chinese physicians.

DESIGN

A self-reporting survey adapted from previous international studies.

SETTING

A teaching hospital in Hebei Province, China.

SUBJECTS

A complete cross-section of 361 physicians working in all hospital departments.

RESULTS

The overall response rate was 79.2%, among whom 15.7% (95% confidence interval (CI) 12.0-20.4) were current smokers and 1.0% ex-smokers (95% CI 0.4-3.1). There were no female smokers when stratified by sex, although the prevalence rate among male physicians was 31.9% (95% CI 24.8-40.0). The prevalence of smoking varied widely by hospital department, ranging from zero in the obstetrics and gynaecology department, to 32.6% in the surgical unit. Smoking rates also varied by age, with physicians younger than 25 years having the lowest prevalence (6.3%). Although they only accounted for 7.1% of the entire group by number, the highest smoking prevalence was seen among physicians aged 50-54 years (31.6%).

CONCLUSIONS

Although our study suggests that smoking is an important health issue for rural Chinese physicians, the distribution of risk is not uniform. Future preventive measures will, therefore, need to consider the individual situation of physicians who smoke, particularly those in the older age groups.

Needlestick and sharps injuries among a cross-section of physicians in Mainland China

BACKGROUND

Although needlestick and sharps injuries (NSI) represent a significant occupational hazard for physicians worldwide, their epidemiology has not been previously examined in Mainland China. This study describes the prevalence, distribution, and risk factors for NSI among a cross-section of Chinese physicians.

METHODS

Data was obtained by an anonymous, self-reporting survey administered to all 361 physicians at a university teaching hospital, during 2004.

RESULTS

Seventy-nine percent of the physicians responded. Among them, 64% had experienced an NSI in the previous 12 months, 50.3% of which involved contaminated devices. By device, 22.8% were caused by hollow-bore syringe needles, 19.1% by suture needles, and 12.1% by scalpel blades. Surgical procedures accounted for 27.9% of all injuries. Only 15.3% of physicians had officially reported their NSI to management, of which 10% went unreported because the individual felt they were not unlucky enough to get a disease. A statistically significant correlation was demonstrated between NSI and working in the intensive care unit (adjusted odds ratio: 5.3, 95% CI: 1.7-23.4).

CONCLUSIONS

Although this study suggests that NSI are an important workplace hazard for Chinese physicians, future measures should consider the unique cultural beliefs of Chinese people and its effect on preventive behaviors. The concept of "luck," and its relationship with NSI reporting in particular, may also need to be addressed.

A Markov chain model for haplotype assembly from SNP fragments

Single nucleotide polymorphism (SNP) is the most frequent form of human genetic variations and of importance for medical diagnosis and tracking disease genes. A haplotype is a sequence of SNPs from a single copy of a chromosome, and haplotype assembly from SNP fragments is based on DNA fragments with SNPs and the methodology of shotgun sequence assembly. In contrast to conventional combinatorial models which aim at different error types in SNP fragments, in this paper we propose a new statistical model - a Markov chain model for haplotype assembly based on information of SNP fragments. The main advantage of this model over combinatorial ones is that it requires no prior information on error types in data. In addition, unlike exact algorithms with the exponential-time computation complexity for most combinatorial models, the proposed model can be solved in polynomial time and thus is efficient for large-scale problems. Experiment results on several data sets illustrate the effectiveness of the new method.

Effects of in utero and lactational exposure to bisphenol A on thyroid status in F1 rat offspring

Bisphenol A (BPA), a xenoestrogen, has been reported to mimic the actions of estrogen or to affect the endocrine glands in vivo and in vitro. In this study, we examined whether in utero and lactational exposure to BPA alters thyroid status in rat F1 offspring. Dams were orally administered various doses of BPA (0, 4 or 40 mg/kg body weight per day) from gestation day (GD) 6 through postnatal day (PND) 20. The BPA and control groups did not differ significantly with respect to plasma thyroxine (T4) concentration. The thyroid glands from the BPA groups had normal T4 responses to exogenous thyroid-stimulating hormone in vivo. These results suggest that in utero and lactational exposure (indirect exposure) to BPA (4-40 mg/kg/day, GD 6 - PND 20) does not affect thyroid functions in the F1 generation of male and female rats.

A review of hazardous chemical toxicity studies utilizing genetically-modified animals--their applications for risk assessment

Studies on the mechanisms of chemical toxicity carried out using knockout mice lacking genes of enzymes for drug metabolism or nuclear receptor proteins were reviewed, and the studies were compared with the respective conventional mechanistic studies. While the toxicity of many hazardous chemicals was observed only in wild-type or knockout mice, which clearly showed that their toxicity was involved in the enzyme or receptor, some chemicals exhibited the same degree of toxicity in two genotypes, i.e., in both the wild strain and knockout mice, demonstrating that the enzymes or receptors are not involved in their toxicity. The use of genetically-modified animals presents not only the advantage of simultaneous evaluation of toxicity endpoints and mechanisms, but also suggests significant benefits over conventional methods using several chemicals to elucidate toxicity mechanisms. Elucidation of the mechanism of toxicity will provide useful information for risk assessment, and the use of genetically-modified animals for this purpose will lead to the advancement of this assessment.

D5hC50X10: Saturn-like fullerene derivatives (X=F, Cl, Br)

Based on the recently reported D(5h) C(50), the geometries and stabilities of its Saturn-like derivatives C(50)X(10) (X=F, Cl, Br) have been investigated by DFT method. Compared with C(50), the equatorial carbon atoms in C(50)X(10) have been saturated by halogens and change to sp(3) hybridization to release the large angle strain. Because the equatorial carbon atoms have been taken out of the pi system by the halogens "ring," the C(50)X(10) system has been split into two well-delocalized conjugated annulene subunits, and then the electronic stabilization has been enhanced.

Kinetics of biglycan, decorin and thrombospondin-1 in mercuric chloride-induced renal tubulointerstitial fibrosis

We investigated the kinetics of decorin, biglycan and thrombospondin-1 in mercuric chloride-treated Brown Norway (BN) rats. BN rats were injected subcutaneously with 1 mg/kg b.w. of mercuric chloride one or three times. The kidney was examined histopathologically and the kinetics of decorin, biglycan and thrombospondin-1 was also examined using immunohistochemistry and real time RT-PCR. As a result, mercuric chloride induced tubular injury and subsequent tubulointerstitial fibrosis. In this lesion, the expression of thrombospondin-1 mRNA was most prominently elevated. The expression of decorin mRNA was next, but biglycan mRNA expression was not elevated. Moreover, decorin and thrombospondin-1 proteins were localized in tubular epithelial cells and peritubular interstitium. Moreover, kinetics of their mRNA expressions was relatively similar to the kinetics of TGF-beta1 mRNA expression previously reported. The present findings suggest that decorin and thrombospondin-1 may participate in the development of tubulointerstitial fibrosis and may have some relation with TGF-beta1 in mercuric chloride-treated BN rats.

Haplotype assembly from aligned weighted SNP fragments

Given an assembled genome of a diploid organism the haplotype assembly problem can be formulated as retrieval of a pair of haplotypes from a set of aligned weighted SNP fragments. Known computational formulations (models) of this problem are minimum letter flips (MLF) and the weighted minimum letter flips (WMLF; Greenberg et al. (INFORMS J. Comput. 2004, 14, 211-213)). In this paper we show that the general WMLF model is NP-hard even for the gapless case. However the algorithmic solutions for selected variants of WMFL can exist and we propose a heuristic algorithm based on a dynamic clustering technique. We also introduce a new formulation of the haplotype assembly problem that we call COMPLETE WMLF (CWMLF). This model and algorithms for its implementation take into account a simultaneous presence of multiple kinds of data errors. Extensive computational experiments indicate that the algorithmic implementations of the CWMLF model achieve higher accuracy of haplotype reconstruction than the WMLF-based algorithms, which in turn appear to be more accurate than those based on MLF.

Interactions of Li, Ca, and Al with aromatic carbon materials: Anab initiostudy

The interactions of benzene (C6H6), naphthalene (C10H8), and perinaphthene (C13H9) with metal atoms (Li, Ca, and Al) were studied using second-order Møller-Plesset perturbation theory. By analyzing the frontier molecular orbitals, geometric structures, binding energies, and charge transfers, it was found that these metal atoms can bond strongly with C13H9, but can only bond weakly with C6H6 and C10H8. The bonding nature between a metal atom and C13H9 at their ground state depends significantly on the valence orbital of the metal atom and the pi-bonding distribution of the aromatic hydrocarbons. The spindly shaped 3p valence orbital of an Al atom results in the deviation of the adsorption site to the edge of C13H9, whereas the ball-shaped 2s/4s valence orbitals of a Li and a Ca atom facilitate their overlap with the second lowest unoccupied molecular orbital of C13H9. Further, Hartree-Fock and density-functional theory methods were demonstrated generally to be unreliable in describing the interactions of metal atoms with these pi systems.

Effects of pregnancy, age and sex in the metabolism of styrene in rat liver in relation to the regulation of cytochrome P450 enzymes

To elucidate the effect of maternal styrene exposure, which is due to various postnatal changes in the development and behavior of offspring, we investigated pregnancy-induced changes in the metabolism of styrene in rat liver in relation to the regulation of cytochrome P450 enzymes. We also examined age and sex-induced changes in the metabolism of styrene. Pregnancy appeared to exert a negative effect on cytochrome P450 content at the late stage, whereas microsomal protein content showed little change during pregnancy. Pregnancy significantly decreased the rate of formation of styrene glycol at the late stage. The percentage of remaining activity in microsomes exposed to anti-CYP2E1 was lower than that exposed to anti-CYP2C11/6 in pregnant and non-pregnant female rats and immature male rats, indicating that CYP2E1 contributes to the metabolism of styrene more than CYP2C11/6 in these rats. Although pregnancy seemed to decrease styrene metabolism, the contribution of CYP2E1 seemed to be slightly increasing. In conclusion, pregnancy clearly influences the metabolism of styrene as well as other characteristic factors such as age and sex. It is very important to elucidate the changes in specific P450 isozyme composition related to their characteristic modification and in their affinity for chemicals.

Musculoskeletal complaints and psychosocial risk factors among Chinese hospital nurses

BACKGROUND

Musculoskeletal complaints represent a common occupational problem for health care workers throughout the world. Despite their sizeable numbers, however, few epidemiological studies have investigated musculoskeletal complaints among Chinese hospital nurses. Objective To assess the prevalence of, and risk factors for, musculoskeletal complaints among hospital nurses in mainland China.

METHODS

A total of 282 female, registered nurses were surveyed (92% response rate) using a modified Chinese-language version of the Standardized Nordic Questionnaire. Body sites were divided into the neck, shoulder, upper back and lower back regions.

RESULTS

The 12 month period-prevalence of musculoskeletal complaints at any of the four regions was 70%. The lower back was the most commonly reported body site (56%), followed by the neck (45%), shoulder (40%) and upper back (37%). High mental pressure, boring or tedious tasks and limited work support were identified as significant risk factors (adjusted odds ratios: 1.79-2.52). No correlations were found between manual handling or perceived physical exertion and increased reporting of musculoskeletal complaints.

CONCLUSION

This study has shown that musculoskeletal complaints are prevalent among Chinese hospital nurses. The correlation with various psychosocial factors is also consistent with evidence from other countries.

Prolonged fever and pyuria: a urinary tract infection presentation of incomplete Kawasaki disease

We report two patients with incomplete Kawasaki disease that presented as apparent urinary tract infection. Persistent fever and pyuria were the initial presentation without concomitant signs suggestive of Kawasaki disease; thus the patients were treated as urinary tract infection. Fever persisted despite antibiotic treatment. Diagnostic criteria of Kawasaki disease were not fulfilled for these two patients, yet aneurysmal dilatation of the coronary artery was noted 10 and 18 d, respectively, after the onset of fever. The diagnosis of incomplete Kawasaki disease was assigned when the coronary artery abnormality was detected. Fever subsided within 24 h of administration of intravenous immunoglobulin.

CONCLUSION

This report highlights the potentially misleading presentation of fever and pyuria as the sole initial manifestation of incomplete Kawasaki disease. Echocardiography is indicated to detect coronary artery abnormality when fever persists in such patients after adequate antibiotic treatment and thorough urological evaluation.