Decreased neurotrophin-3 expression of intrafusal muscle fibers in rat soleus muscles under simulated weightlessness / 生理学报

The present study aimed to study the changes of neurotrophin-3 (NT-3) expression of intrafusal muscle fibers in rat soleus muscles under simulated weightlessness. The tail-suspension (SUS) rat model was used to simulate weightlessness. Forty mature female Sprague-Dawley rats were randomly assigned to ambulatory control (CON), 3-day SUS, 7-day SUS, 14-day SUS and 21-day SUS groups. Immunohistochemistry ABC staining method and enzyme linked immunosorbent assay (ELISA) were used to detect the NT-3 expression of intrafusal muscle fibers in rat soleus muscles. The results from the immunohistochemistry staining technique showed that the extrafusal muscle fibers did not exhibit the NT-3-like immunoreactivity, and NT-3-like immunoreactivity was mainly expressed in nuclear bag 1 and nuclear bag 2 fibers of the muscle spindles. The ELISA results showed that the expression quantity of NT-3 in rat soleus muscles in control, 3-day SUS, 7-day SUS, 14-day SUS and 21-day SUS groups were (14.23±1.65), (14.11±1.53), (13.09±1.47), (12.45±1.51) and (9.85±1.52) pg/mg of tissue respectively. Compared to the control group, the expression quantity of NT-3 was significantly decreased after 14 days of SUS (P<0.05). After 21 days of SUS, the NT-3 expression was further reduced (P<0.01). These results suggest that simulated weightlessness induces an obvious decrease in the NT-3 expression level of intrafusal fibers in rat soleus muscles. Accompanying the simulated weightlessness extension, NT-3 expression in rat soleus muscle spindles is progressively decreased. These changes may contribute to the proprioceptive adaptations to microgravity.

Risk factors analysis in hospital-acquired pneumonia caused by nonfermentative bacteria / 中国感染与化疗杂志

Objective To analyze the risk factors of hospital acquired pneumonia (HAP) caused by nonfermentative bacteria in ICU.Methods Using binary logistic regression analysis,we reviewed the related risk factors of hospital acquired pneumonia caused by nonfermentative bacteria from January,2002 to May,2006 in ICU of our hospital.Results Univariate regression ana- lysis identified 22 variables associated with HAP,including age,diabetes mellitus,malignant tumor,chronic obstructive pul- monary disease (COPD),smoking,Glasgow Coma Scale (GCS) score,Acute Physiology and Chronic Healthy EvaluationⅡ(APACHEⅡ) score.Multivariate regression analysis confirmed 6 high risk factors:aspiration,COPD,use of antacids,seda- tive agents,mechanical ventilation and tracheal intubation or tracheostomy.Conclusions Aspiration,COPD,use of antacids, sedative agents,mechanical ventilation,tracheal intubation or tracheostomy are high risk factors associated with HAP.