Recovery of motor function in rats with complete spinal cord injury following implantation of collagen/silk fibroin scaffold combined with human umbilical cord-mesenchymal stem cells

SUMMARY OBJECTIVE: This study aimed to assess the effect of the collagen/silk fibroin scaffolds seeded with human umbilical cord-mesenchymal stem cells on functional recovery after acute complete spinal cord injury. METHODS: The fibroin and collagen were mixed (mass ratio, 3:7), and the composite scaffolds were produced. Forty rats were randomly divided into the Sham group (without spinal cord injury), spinal cord injury group (spinal cord transection without any implantation), collagen/silk fibroin scaffolds group (spinal cord transection with implantation of the collagen/silk fibroin scaffolds), and collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (spinal cord transection with the implantation of the collagen/silk fibroin scaffolds co-cultured with human umbilical cord-mesenchymal stem cells). Motor evoked potential, Basso-Beattie-Bresnahan scale, modified Bielschowsky's silver staining, and immunofluorescence staining were performed. RESULTS: The BBB scores in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group were significantly higher than those in the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). The amplitude and latency were markedly improved in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). Meanwhile, compared to the spinal cord injury and collagen/silk fibroin scaffolds groups, more neurofilament positive nerve fiber ensheathed by myelin basic protein positive structure at the injury site were observed in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (p<0.01, p<0.05). The results of Bielschowsky's silver staining indicated more nerve fibers was observed at the lesion site in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.01, p< 0.05). CONCLUSION: The results demonstrated that the transplantation of human umbilical cord-mesenchymal stem cells on a collagen/silk fibroin scaffolds could promote nerve regeneration, and recovery of neurological function after acute spinal cord injury.

Evaluation on the accuracy of obese indexes in predicting obstructive sleep apnea-hypopnea syndrome in male adults / 中华流行病学杂志

<p><b>OBJECTIVE</b>To determine the best cutoff value and reference standard of obese indexes and to compare their diagnostic value in screening, predicting and diagnosing obstructive sleep apnea-hypopnea syndrome (OSAHS) in male adults by receiver operating characteristic curve (ROC).</p><p><b>METHODS</b>A total of 1110 male adults were included and cross-sectional study was adopted. Four parameters including: body mass index (BMI), neck circumference (NC), waist circumference (WC) and waist-to-hip ratio (WHR) were studied. The correlativity between apnea-hypopnea index (AHI) and BMI, NC, WC and WHR were analyzed by pearson correlation test. ROC curve was used to assess the diagnostic value and determine their best cutoff value to predict OSAHS and reference standard to screen/diagnose it. Their conformity in predicting OSAHS was analyzed by area under curve (AUC). SPSS software version 13.0 was used for statistical analysis and P< or =0.05 was considered to indicate statistical significance.</p><p><b>RESULTS</b>(1) All of the fourindexes (BMI, NC, WC and WHR) showed a significantly positive correlation with AHI in adult male patients, with their Pearson coefficients as 0.373, 0.276, 0.291 and 0.127, respectively, and their P value were all below 0.001; (2) The best cutoff value of BMI, NC and WC in predicting OSAHS were 26.5 kg/m2 , 39 cm, 95 cm, and their corresponding sensitivity rates were 54%, 57% and 64% while rates of specificity as 73%, 65% and 53%; (3) BMI was better than other two indexes in predicting OASHS in adult male patients; (4) The value of BMI, NC and WC in screening OSAHS among adult male patients with 90% sensitivity and 10% rate of missed diagnosis as 23 kg/m2, 35 cm, 85 cm; (5) The value of BMI, NC and WC in screening OSAHS in adult male patients with 90% specificity and 10% misdiagnosis rate as 29 kg/m2, 43 cm, 105 cm, respectively.</p><p><b>CONCLUSION</b>BMI seemed better in predicting OSAHS in male adults than NC, WC and WHR. The best cutoff values to predict OSAHS of BMI, NC and WC were 26.5 kg/m2, 39 cm and 95 cm, respectively. Their reference standards to screen OSAHS were 23 kg/m2, 35 cm and 85 cm while 29 kg/m2, 43 cm and 105 cm to predict OSAHS.</p>