Concentrations of cadmium and zinc in seawater of Bohai Bay and their effects on biomarker responses in the bivalve Chlamys farreri

Both in-field chemical investigation and in the laboratory toxic tests were carried out to systematically understand the pollution status of cadmium (Cd) and zinc (Zn) in Bohai Bay. Samples collected from surface seawater were determined to describe the distributions of Cd and Zn in Bohai Bay. The average values in our study of Cd and Zn were 0.15 microg/L and 19.68 microg/L, respectively. Both of them were lower than the first class limit of seawater quality standard in China. In the laboratory, antioxidant enzymes [SOD (Cu/Zn-SOD, Mn-SOD), CAT], lipid peroxidation (MDA), phase I and phase II enzymes (CYP4501A and GST) were investigated in the bivalves Chlamys farreri exposed to Cd and Zn at the concentration levels of Bohai Bay seawater, which were obtained from our in-field investigation. The reduced SOD, CAT, and EROD (7-ethoxyresorufin-O-deethylase) activities (with the inhibitory rate of 16.8%, 31.5%, and 51.6%, respectively) in Cd treatment were observed and resulted in obvious lipid peroxidation damage. However, treatment of Zn showed elevations in SOD and GST by 13.3% and 29.9%, respectively, and with no influence on lipid peroxidation. In summary, seawater quality in Bohai Bay seawater was ranked as good in general, but it seemed that Cd might possess a potential environmental risk by effecting pro-oxidant/antioxidant balance and phase I detoxification in C. farreri.

The structure and functions of P-glycoprotein

P-glycoprotein (P-gp) is an ATP-driven transmembrane transporter capable of effluxing a wide variety of structurally diverse and functionally unrelated hydrophobic compounds out of the cell. Multidrug resistance (MDR), often associated with the over-expression of P-gp, has been implicated as a major obstacle to effective chemotherapy for cancer, parasitic diseases, AIDS, and other diseases. Drug efflux mediated by P-gp is also involved in decreasing the oral bioavailability of drugs by limiting intestinal absorption. Our appreciation of the structural and functional aspects of P-gp has definitely improved in recent years, benefiting from the deciphering of the structure of some bacterial transporters that paved the way for construction of homology models for more complex transporters. Here, we will review the recent advances in the studies of the structure and functional characteristics of P-gp with the hopes of facilitating rational drug design in developing novel potent MDR modulators.

Heterotopic bone formation by nano-apatite containing poly(D,L-lactide) composites

To render polymeric materials osteoinductive, nano-sized calcium phosphate apatite particles (CaP) were introduced into a low molecular weight poly(D,L-lactide). Homogenous composites were made with 10%, 20% and 40% by weight of apatite content while pure polylactide was used as control. Thereafter porous samples (pore size 300-400 microm, 60% porosity) were fabricated and sterilized. In vitro studies showed that calcium ions were released from the composites depending on the apatite content, while surface mineral deposition was observed only on the 40% CaP composites in simulated body fluid (SBF) within 14 days. After 12 weeks of intramuscular implantation in dogs, only the 40% CaP composite implant retained its shape and showed ectopic bone formation within the pores. In conclusion, adding a content of 40% apatite into poly(D,L-lactide) could lead to an osteoinductive material. Future studies will focus on understanding this phenomenon of material-directed osteoinduction in order to develop a promising bone graft substitute.

Corticotrophin-releasing hormone (CRH) facilitates axon outgrowth

OBJECTIVE

To evaluate the role of corticotrophin-releasing hormone (CRH) in facilitating axon outgrowth.

BACKGROUND

Injured neural tissue is difficult to regenerate; the mechanism has not been fully understood.

METHODS

A rat model of spinal cord transection injury was developed. Levels of BDNF, CRH and oligodendrocyte glycoprotein (OMgp) in injured spinal cord were monitored dynamically after surgery. Cellular interaction among rat dorsal root ganglia (DRG) cells, oligocondrocytes and microglial cells was observed with a coculture model. The axon outgrowth from DRG cells was examined by confocal microscopy.

RESULTS

After spinal cord transection, levels of BDNF and CRH increased the next day and decreased afterward, whereas OMgp levels increased from day 3. Administration with BDNF suppressed the levels of OMgp in vitro. The results from a coculture model showed that CRH increased microglial cells to release BDNF; BDNF inhibited OMgp levels in oligodendrocytes and enhanced the axon outgrowth from DRG cells.

CONCLUSIONS

This study shows that CRH has the ability to facilitate the outgrowth of axon in spinal neurons, which has therapeutic potential in the treatment of spinal cord injury.

Estimation of the cortical activity from simultaneous multi-subject recordings during the prisoner's dilemma

One of the most challenging questions open in Neuroscience today is the characterization of the brain responses during social interaction. A major limitation of the approaches used in most of the studies performed so far is that only one of the participating brains is measured each time. The "interaction" between cooperating, competing or communicating brains is thus not measured directly, but inferred by independent observations aggregated by cognitive models and assumptions that link behavior and neural activation. In this paper, we present the results of the simultaneous neuroelectric recording of 5 couples of subjects engaged in cooperative games (EEG hyperscanning). The simultaneous recordings of couples of interacting subjects allows to observe and model directly the neural signature of human interactions in order to understand the cerebral processes generating and generated by social cooperation or competition. We used a paradigm called Prisoner's dilemma derived from the game theory. Results collected in a population of 10 subjects suggested that the most consistently activated structure in social interaction paradigms is the orbitofrontal region (roughly described by the Brodmann area 10) during the condition of competition.

Pharmacokinetics and anti-inflammatory pharmacodynamics of prednisolone in cynomolgus monkey

The purpose was to investigate whether the pharmacokinetics and pharmacodynamics of prednisolone in the non-human primate was an appropriate surrogate for man. After single intravenous doses of 0.03, 0.3, and 3 mg kg(-1), prednisolone demonstrated a dose-dependent clearance and volume of distribution. When corrected for concentration-dependent protein binding, the free clearance was linear at the tested dose levels. The protein binding-corrected volume of distribution was similar across doses. The serum half-life was estimated as being between 2 and 4 h. Prednisolone exhibits near complete inhibition of the cytokines TNF-alpha, IL-1beta, IL-6 and IL-8 with very similar IC50 estimates from 0.09 to 0.16 microg ml(-1) (from 0.24 to 0.44 microM). The monkey demonstrated a similar pharmacokinetics-pharmacodynamics profile of prednisolone when compared with man (from the literature).

Clinical Significance of Telomerase Activity in Gastric Carcinoma and Peritoneal Dissemination

Telomerase activity is responsible for telomere maintenance and is believed to be crucial in most cancer cells, but its significance in gastric cancer remains unknown. This observational study investigated whether there is a relationship between telomerase activity and the development of gastric cancer, and between telomerase activity and peritoneal dissemination. Telomerase activity was measured in primary gastric cancers and in peritoneal washings from the same patients, and findings were compared with those of conventional cytology and an immunoassay for cancer antigen 125 (CA125). Positive cytological examination and telomerase activity in peritoneal washings both correlated with the histological grade, depth of tumour invasion, area of serosal invasion and peritoneal metastasis. The detection of free cancer cells in peritoneal washings by the telomeric repeat amplification protocol/enzyme-linked immunosorbent assay (TRAP–ELISA) was significantly more sensitive than cytology or the CA125 immunoassay, suggesting that this could be used to diagnose early peritoneal dissemination.

Persistent organic pollutant residues in the sediments and mollusks from the Bohai Sea coastal areas, North China: an overview

The Bohai Sea costal area is one of the most developed zones of China and the sewage water from populous and developed cities, including Beijing, Tianjin, Qinhuangdao and Dalian is discharged into the Bohai Sea. Additionally, its semi-enclosed characteristic restricts water exchange, which leads to high accumulation of pollutants in the environment. This overview presents the residues of 6 classes of Persistent Organic Pollutants (POPs), including PAHs, DDTs, HCHs, PCBs and PCDD/Fs, in the sediments and mollusks of the Bohai Sea through analyzing previous literatures. In the sediments, the highest PAH concentrations were detected in the vicinities of Qinhuangdao, while the northeast corner of the Bohai Bay possessed the highest levels of DDTs and PCBs. The investigations on HCHs and PCDD/Fs distributions on the whole sea scale have not been reported. In mollusks, PAH concentrations were in the same order of magnitude in the whole Bohai Sea, so were DDTs, HCHs and PCBs, while the outlier maximum values of PCDDs and PCDFs occurred in Yingkou. In general, the POPs residues in mollusks collected from Shandong Province were higher than the other areas. The compositions of DDTs, HCHs and PCBs in sediments indicated their recent usage. By comparing POP concentrations in sediments with the recommended criterions, it was shown that some individual PAH compounds occasionally associated with adverse biological effects in the vicinities of the Liaodong Bay and Qinhuangdao, and the Liaohe River Estuary were heavily contaminated with DDTs, but PCBs were all below the thresholds. In order to reveal the transference and transformation of POPs in the environment, further studies concerning with their behavior, fate and bioaccumulation in the different trophic levels should be programmed. Moreover, laws and regulations should be enforced to ban the illegal usage of POPs-containing pesticides to guarantee health of the environment and human.

One century record of contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls in core sediments from the southern Yellow Sea

Sixteen polycyclic aromatic hydrocarbons (PAHs) and 28 polychlorinated biphenyls (PCBs) were measured at a 2-cm interval in a core sample from the middle of the southern Yellow Sea for elucidating their historical variations in inflow and sources. The chronology was obtained using the 210pb method. PAHs concentrations decreased generally with depth and two climax values occurred in 14-16 cm and 20-22 cm layers, demonstrating that the production and usage of PAHs might reach peaks in the periods of 1956-1962 and 1938-1944. The booming economy and the navy battles of the Second World War might explain why the higher levels were detected in the two layers. The result of principal component analysis (PCA) revealed that PAHs were primarily owing to the combustion product. Down-cored variation of PCB concentrations was complex. Higher concentrations besides the two peaks being the same as PAHs were detected from 4 to 8 cm, depositing from 1980 to 1992, which probably resulted from the disposal of the out-dated PCB-containing equipment. The average Cl percentage of PCBs detected was similar to that of the mixture of Aroclor 1254 and 1242, suggesting they might origin from the dielectrical and heat-transfer fluid. The total organic carbon (TOC) content played a prevalent role in the adsorption of high molecular weight PAHs (> or = 4-ring), while no obvious relationship among total PCBs, the concentration of congeners, and TOC was found.

Effects of Polymorphism of the β1 Adrenoreceptor and CYP2D6 on the Therapeutic Effects of Metoprolol

Metoprolol is a lipophilic β1 selective adrenergic receptor antagonist used in antihypertensive therapy. It is metabolized by the protein product of the cytochrome P450 2D6 ( CYP2D6) gene. Few studies have been performed on the association between the β1 adrenoreceptor, CYP2D6 polymorphism and blood pressure. The one reported here is a prospective, observational, clinical study in Chinese Han hypertensive patients on the combined influences of CYP2D6 and β1 adrenoreceptor polymorphisms on the therapeutic effects of metoprolol in 300 out-patients with essential hypertension. The same dose of metoprolol achieved different therapeutic effects in patients with different CYP2D6 and β1 adrenoreceptor polymorphisms. Additionally, different doses of metoprolol could achieve the same therapeutic effects in patients with different CYP2D6 and β1 adrenoreceptor polymorphisms. Knowledge of the combination of CYP2D6 and β1 adrenoreceptor polymorphisms may be used to guide antihypertensive therapy using β1 adrenoreceptor antagonists.

Audiological and genetic features of the mtDNA mutations

CONCLUSIONS

Significant difference in the incidence of mitochondrial DNA (mtDNA) mutations was found between the Chinese and USA populations. The identification of the mtDNA A1555G mutation in a large proportion of Chinese probands with nonsyndromic sensorineural hearing loss (NSHL) provides a molecular explanation for the high prevalence of aminoglycoside-induced deafness in China.

OBJECTIVE

The aim was to characterize the audiological and genetic features of NSHL due to mutations in mtDNA.

SUBJECTS AND METHODS

The mtDNA and audiogram analyses were performed in 498 NSHL patients (290 from China and 208 from the USA) with and without history of aminoglycoside exposure. A PCR and restriction enzyme digestion protocol was used for mutational screening and the European Workshop on Genetic Hearing Loss criteria were applied for audiological classification.

RESULTS

All Chinese probands (15.5%) with mtDNA mutation were found to carry the homoplasmic mtDNA A1555G mutation, whereas four probands (1.9%) from the USA were found to carry the mtDNA A1555G and two (1%) had mtDNA G7444A. Approximately 63% of the probands with mtDNA mutations had post-lingual hearing loss and 56.8% of them had a medical history of exposure to aminoglycosides. Hearing losses are bilateral, sensorineural, and symmetric. The main audiogram shapes found were sloping.

Prevalence of irritable bowel syndrome among undergraduates in Southeast China

BACKGROUND

There is a wide range in reported prevalence of irritable bowel syndrome worldwide. From the data appeared recently in medical literatures in China, it seems that the incidence of irritable bowel syndrome in young adults is not dissimilar to the one in the Western countries.

AIMS

To explore the prevalence and epidemiological variations of irritable bowel syndrome in an undergraduate student population in Southeast China on the basis of the Rome II and Rome III criteria.

METHODS

All the undergraduate student participants were administered self-report diagnostic measures for irritable bowel syndrome.

RESULTS

The sex-adjusted prevalence rate of irritable bowel syndrome was 4.7% (Rome II) and 10.4% (Rome III), respectively. When we combined irritable bowel syndrome mixed and irritable bowel syndrome unsubtyped in the Rome III subgroups into one group considering the counterpart in the Rome II subgroups was alternative irritable bowel syndrome, the agreement between the two ways to subdivide these 54 patients who were identified with irritable bowel syndrome by both the two criteria was 81%, with a kappa value of 0.67. By the Rome III criteria, we found a female predominance which was especially attributed to the subtypes of irritable bowel syndrome with constipation and unsubtyped.

CONCLUSIONS

Our study suggests that, in young adults in Southeast China, changing diagnostic criteria for irritable bowel syndrome from Rome II to Rome III may affect women more than men on not only the overall prevalence rate but also the sex-difference present or not, especially in irritable bowel syndrome with constipation and irritable bowel syndrome unsubtyped subgroups.

A high resolution EEG study of dynamic brain activity during video game play

A high resolution EEG study was conducted on healthy human subjects during video game play. Throughout the game playing experiment short time segments of spontaneous activity were recorded. Spectral analysis was performed on these segments for the theta-wave (4-8 Hz) and alpha-wave (8-13 Hz) bands to investigate the modulatory effects of long-lasting game play and the dynamic changes of spectral contribution in range of alpha-and theta-wave. The present results revealed that a) the frontal midline theta-wave activity increased over time relative to the eye open resting condition and b) the parietal alpha-wave activity initially decreased relative to the resting condition, then followed by a slow increase. These experimental results indicate the high resolution EEG provides a useful quantitative analysis tool for studying dynamic brain activity.