Preparation and biocompatibility of polyethylene glycol hydrogels auto-recruiting transforming growth factor beta1 / 中国组织工程研究

BACKGROUND:Studies have shown that bioactive molecules or polypeptides grafted onto the surface of polyethylene glycol (PEG) hydrogels can improve PEG bioactivities.OBJECTIVE:To manufacture PEG hydrogels capable of auto-recruiting growth factor beta1 (TGF-β1) and to study its biocompatibility. METHODS:Pure PEG hydrogels (group A), PEG hydrogels grafted on a cell adhesion peptide RGD peptides (group B), PEG hydrogels grafted with auto-recruited TGF-β1 peptide sensitive polypeptide HSNGLPL (group C), PEG hydrogels grafted with both RGD and HSNGLPL polypeptides (group D) were prepared. Contract angle of the hydrogel was detected in each group. Human bone mesenchymal stem cells were seeded onto four kinds of hydrogels. After cells attached, scanning electron microscope and LIVE/DEAD staining were done to observe cell-hydrogel compounds. Human bone marrow mesenchymal stem cells were co-cultured with ordinary culture medium (control) or four kinds of hydrogels for 1, 3, 5, 7 days, and the cell proliferation was detected by cell counting kit-8 assay. The four kinds of hydrogels were put into 24-well culture plates with addition of PBS containing TGF-β1, and 1 hour later, immunofluorescence staining was done. RESULTS AND CONCLUSION:(1) The contact angles of groups A and C were larger than those of groups B and D. (2) Under the scanning electron microscope, groups A and C had little cells attached on the hydrogel surface, but there were many cells on the hydrogel surface in groups B and D. (3) LIVE/DEAD staining showed groups A and C had little living cells, and conversely groups B and D had many living cells. (4) The results of cell counting kit-8 demonstrated that as the incubation time went on, cell proliferation activity of five different groups increased with no difference at the same time point. (5) Findings from the immunofluorescence staining showed that groups A and B had very weak fluorescence, while groups C and D had stronger green fluorescence. In conclusion, PEG hydrogels grafted with RGD and HSNGLPL polypeptides can auto-recruit TGF-β1, and have good biocompatibility.

Effect of Xinmailong on hypoxia-inducible factor-1alpha expression in neonatal rats with asphyxia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Xinmailong, a compound extracted from Periplaneta americana, is used for the treatment of cardiovascular diseases. This study investigated the effects of Xinmailong on myocardial hypoxia-inducible factor-1alpha (HIF-1alpha) and plasma endothelin-1(ET-1) levels in neonatal rats with asphyxia and explored the protection mechanism of Xinmailong in hypoxia-ischemic myocardial injury.</p><p><b>METHODS</b>Seven-day-old Sprague-Dawley rats were randomly divided into three groups (n=30 each): sham-operated, asphyxia, Xinmailong-treated asphyxia. Each group was randomly subdivided into three groups according to the observed time points: 6 hrs, 24 hrs and 72 hrs. Xinmailong (5 mg/kg) was intraperitoneally injected to the rats in the Xinmailong-treated group five minutes before asphyxia. Myocardial HIF-1alpha expression, and plasma ET-1 and creatine kinase (CK) levels were measured. The histopathologic changes of the myocardium were observed by hematoxylin-eosin staining.</p><p><b>RESULTS</b>Four rats died in the asphyxia group while only one died in the Xinmailong-treated group during the experiment. The plasma ET-1 and CK levels as well as myocardial HIF-1alpha expression increased at 6 hrs, reached a peak at 24 hrs, and declined at 72 hrs after asphyxia in the asphyxia group, being higher than that in the sham-operated group (P<0.01). Myocardial ischemia was observed in the three time points, and cell necrosis occurred at 24 hrs after asphyxia in the asphyxia group. Myocardial HIF-1alpha expression was positively correlated with plasma ET-1 levels (r=0.876, P<0.01). In the Xinmailong-treated group, plasma levels of CK and ET-1 as well as myocardial HIF-1alpha expression were significantly lower than those in the asphyxia group (P<0.01). Myocardial ischemia was alleviated and no cell necrosis was found in the Xinmailong-treated group.</p><p><b>CONCLUSIONS</b>Asphyxia leads to increase in myocardial HIF-1alpha expression and plasma levels of ET-1 and CK. Xinmailong can reduce the myocardial expression of HIF-1alpha and decrease plasma ET-1 levels, thus alleviating hypoxia-ischemic myocardial injury.</p>

Long-term outcomes of the revision open lumbar discectomy by fenestration: a follow-up study of more than 10 years / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the long-term clinical results and the factors that influences the outcomes of the revision open lumbar discectomy by fenestration.</p><p><b>METHODS</b>Fifty-one patients, who underwent the second open discectomy by fenestration from January 1 1988 to December 31 1994, were followed for an average of 146.8 months (range, 120 to 203 months). The long-term follow-up results were evaluated by using the MacNab classification and the Japanese Orthopaedic Association (JOA) scoring system through direct examinations and questionnaires. Radiography was also used in patients who agreed to visit the hospital, and findings were compared with those on preoperative radiographs.</p><p><b>RESULTS</b>At the final follow-up, with the MacNab classification an excellent and good outcome was achieved in 70.6% of the cases, 78.4% were satisfied with their results. The failure rate was 15.7% (8 patients). Excluding those 8 failed cases who needed another reoperation, the average improvement calculated by JOA scores was (64.6 +/- 18.2)%. The disc height of the operation site significantly decreased after surgery, nevertheless, this did not affect the long-term clinical outcome. Factors that were associated with a fair and bad outcome included smoking, isolated trauma or injury, fibrosis and the length of the remaining or recurrent primary postoperative symptoms history. Psychosociological signs were probably known as negative predictors of lumbar disc surgery outcome.</p><p><b>CONCLUSION</b>The long-term outcome of the revision open lumbar discectomy by fenestration in this series was favorable. Because the revision operation is typically associated with a higher complexity, selection of suitable surgical candidates and determination of valid indications for operative treatment are very important. JOA scores have proved to be easy to perform for patients and clinicians and standardize subjective data.</p>

Secondary structure of insulin encapsulated within liposomes / 药学学报

<p><b>AIM</b>To determine the secondary structure of insulin encapsulated within liposomes.</p><p><b>METHODS</b>The secondary structure of insulin, mixture of insulin with liposomes (I) and insulin liposomes (II) were determined by Fourier transform infrared (FTIR) spectroscopy.</p><p><b>RESULTS</b>The figures of secondary structure of insulin, sample I and II were similar. The results showed that the amount of alpha-helix and beta-sheet of insulin, sample I and II had little difference, from 36.09% (insulin) to 31.68% (sample I) and 31.45% (sample II), and from 47.83% (insulin) to 53.29% (I) and 51.36% (II), respectively. The results showed that the insulin of sample I and II did not insert in liposomes membrane, only adsorbed or extendedon the surface of the liposomes.</p><p><b>CONCLUSION</b>The secondary structure of insulin encapsulated within liposomes has not been destroyed and still remain the original state.</p>