Objective To investigate and analyze the recent condition of the indoor air radon concentration in the colleges in Guangzhou and to find the source of radon in the teaching environments and to make the effective measure to reduce indoor air radon pollution. Methods The radon concentration was determined with the instantaneous and accumulate methods. The effecting factors were analyzed. Results The arithmetic average of radon concentration was about (34.2?21.17) Bq/m3. The indoor radon concentration in the newly decorated buildings was about (36.6?25.5) Bq/m3 which was higher than that in the old ones (20.1?8.48) Bq/m3. The indoor radon concentration in the night was higher than that in the daytime. In winter it was about (54.2?15.11)Bq/m3 which was higher than that (17.3?7.31) Bq/m3 in summer. Conclusion The radon concentration may change as the outside condition changes, the radon concentration in the teaching environment in Guangzhou is not over the standard limit.

Objective To evaluate the effect of long term home non-invasive positive pressure ventilation (HNIPPV ) in stable severe chronic obstructive pulmonary disease (COPD) .Methods Forty-two patients with stable severe COPD after hospital dis-charge were divided into 2 groups :The observation group (conventional treatment + HNIPPV ,22 patients) and control group (con-ventional treatment ,20 patients) .Parameters before and after one year follow-up observation were compared ,which includes arterial bloods gases ,lung function test ,6-min walking distance(6MWD) ,dyspnea grade ,scoring for emotional disorders ,the hospitalization rates .Results PaCO2 ,PaO2 ,6MWD ,dyspnea grade ,scoring for emotional disorders ,the hospitalization rates improved after one year in the observation group (P < 0 .05) .There were no significance of FVC and FEV1 between the two groups after one year . There were no patients who were dead or exited with other reason after one year in the two groups .Conclusion Long term HNIP-PV could decrease exacerbations ,respiratory failure and increase life quality ,this therapy is effective and safe for patients with sta-ble severe COPD .

Objective To study changes and significance of endothelin(ET) in rat cerebral concussion.Methods 80 Wistar male rats were used for animal model of cerebral concussion,which were sacrificed on 1,3,7,14 and 30 days after injury and the brain tissue were taken off. The expression of ET was studied in the course of cerebral concussion by means of immunohistochemistry.Results Typical clinical manifestation was observed in the 100 g group in which the pathological changes included cerebral vascular constriction and dilatation,congestion and edema of cerebral tissue,neuronal degeneration,necrosis,and obviously decreased even disappeared Nissl bodies.Increased expression of ET was observed on the first day,the positive area was seen in the plasma of endothelial cells in cerebral cortex,hippocampus,cerebellum and thalamus.ET expression peak occurred on the 7th day,the positive area was also found in the plasma of Purkinje cells in the cerebellum.Decreased ET expression was found on 14th day and returned to normal level on the 30th day.Conclusion The main pathological changes of cerebral concussion contained blood circulation disorder,and degeneration and necrosis of substantial cells.ET was involved in the brain tissue injury during the pathological process of cerebral concussion and might be related to regulation of cerebral vascular reaction,and neuron degeneration and necrosis.