Effects of 3,3′,4,4′,5-pentachlorobiphenyl on human Kv1.3 and Kv1.5 channels

Among the environmental chemicals that may be able to disrupt the endocrine systems of animals and humans are polychlorinated biphenyls (PCBs), a chemical class of considerable concern. PCB consists of two six-carbon rings linked by a single carbon bond, and theoretically, 209 congeners can form, depending on the number of chlorines and their location on the biphenyl rings. Furthermore, 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) exposure also increases nitric oxide production and nuclear factor kappa-light-chain-enhancer of activated B cells binding activity in chondrocytes, thus contributing as an initiator of chondrocyte apoptosis and resulting in thymic atrophy and immunosuppression. This study identified whether cardiac and immune abnormalities from PCB126 were caused by the Kv1.3 and Kv1.5 channels. PCB126 did not affect either the steady-state current or peak current of the Kv1.3 and Kv1.5 channels. However, PCB126 right-shifted the steady-state activation curves of human Kv1.3 channels. These results suggest that PCBs can affect the heart in a way that does not block voltage-dependent potassium channels including Kv1.3 and Kv1.5 directly.

A Comparative Study on Job Stress and Satisfaction between Ward Nurses and Outpatient Nurses / 한국직업건강간호학회지

PURPOSE: This study was to compare job stress and job satisfaction between ward nurses and outpatient nurses, and to identify the correlation between job stress and job satisfaction. METHODS: The subjects of this study were 200 ward nurses and 85 outpatient nurses in G and I University Hospital in Incheon. The data were collected in March 2010 and analyzed with t-test and Pearson correlation coefficient. RESULTS: There was no significant difference in overall job stress between two groups, but slightly higher stress level for ward nurses. In sub-area of job stress, 'nursing duty' was primary for both groups. And in 'nursing duty' (t=2.05, p=.041), 'conflict with patients' (t=2.73, p=.007), and 'working environment' (t=3.37, p<.001) ward nurses showed significant higher level of stress than outpatient nurses. For job satisfaction, outpatient nurses showed higher level significantly (t=-2.98, p=.003). And both groups of nurses' job satisfaction was negatively correlated with job stress significantly (r=-.31, p<.001). CONCLUSION: It will be possible to reduce job stress and promote job satisfaction level for both groups of nurses by adding staffs, and specifically for ward nurses by improving facilities for relax and appropriate supply, and for outpatient nurses by managing interpersonal stress and reducing side tasks.

A study of the anti-rotating inner post screw system as a means of preventing abutment screw loosening / 대한치과보철학회지

STATEMENT OF PROBLEM: The most commonly reported problem associated with dental implant restoration is the loosening of the screws. PURPOSE: This study compared the efficacy of an implant system incorporating an anti-rotational locking sleeve(Anti-Rotating Inner Post Screw System(ARIPS-system)) with other, traditional implant systems as a means of minimizing vibration loosening. MATERIALS AND METHODS: Three implant systems were examined; the conventional external hex type, the ARIPS-system, and the internal taper type implant system. 30 specimens(10 samples per group)were fabricated and each abutment screw was secured to the implant fixture with 32Ncm of torque force and loosening torque was measured using a Torque Gauge. The procedure was repeated 3 times, recording initial loosening torque each time. The re-tightened abutment screw was subjected to a cyclic load having a maximum force of 200N and minimum of 20N at 2Hz over a period of 12,600 cycles, after which the loosening torque was measured. Measured values were calaulated for statistical analysis. Analysis of measured value was performed by 3 methods: (i) as a percentage average of the initial 3 loosening-torque values(initial loosening value) to the tightening torque of 32Ncm, (ii) as a percentage of the loosening torque value after a load of 200N(experimental value) to the initial loosening value, and (iii) as a percentage of the experimental value to the 32Ncm of tightening torque. The analyses shows the amount of initial loosening at the screw, loosening by repetitive load and the the final loosening value. RESULTS: The results of this study were as follows. (1) Percentage of initial loosening value to tightening-torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p<0.05). (2) Percentage of experimental value to initial loosening value was increased in order of external hex, ARIPS-system and internal taper. Value of internal taper showed significant difference with those of external hex and ARIPS-system (p <0.05). (3) Percentage of experimental value to tightening torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p <0.05). CONCLUSION: The results of the analysis of the final loosening level value, which are closely correlated to clinical use, show that the ARIPS-system can be a useful means of minimizing abutment screw loosening when compared to the external hex type system. Although further clinical studies need to be made, the ARIPS-system should be considered to maximize the long-term success of the implant prosthesis.