0.05). 6 cases of Hirschsprung′s disease showed microcolon with the appearances of shortage of colon frame, barium reflux into distal ileum and barium retention. Conclusion Local notch of the distal rectum, spiral or irregular bizarre saw-toothed contractions of the rectum and distal sigmoid colon, and delayed evacuation of barium are 3 valuable radiographic signs. Colitis itself isn′t a valuable diagnostic radiographic sign of Hirschsprung′s disease. It only shows inflammation of colon. And microcolon with the appearances of shortage of colon frame, barium reflux into distal ileum, and barium retention may suggest the diagnosis of total aganglionic colon.

OBJECTIVETo prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material.

METHODSSodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted microscope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate.

RESULTSSodium alginate-nanohydroxyapatite composite material displayed porosity, the porous pore rate was (88.6 +/- 4.5)%. BMSCs showed full stretching and vigorous growth under inverted microscope and SEM. BMSCs cultured with liquid extracts of the material had good activities. The toxicity of composite material was graded as 1. Hemolysis test results showed that the hemolysis rate of the composite material was 1.28%, thus meeting the requirement of medical biomaterials.

CONCLUSIONThe composite material fabricated in this study has high porosity and good biocompatibility.

Alginates ; Biocompatible Materials ; Cells, Cultured ; Glucuronic Acid ; Hexuronic Acids ; Humans ; Mesenchymal Stromal Cells ; Porosity ; Tissue Engineering ; Tissue Scaffolds

Infection is the most common disease in children and a major problem that plagues clinicians.Imaging examination is an important tool for the diagnosis and evaluation of infectious diseases, providing evidences for early diagnosis.Although the imaging can not identify the pathogen, it can provide important clues for the determination of the pathogen, narrow the scope of the suspected pathogens, and provide a basis for the clinician′s empirical treatment.

Objective To evaluate aorta's compliance after repair of coarctation of the aorta (CoA)using the pulse wave velocity (PWV)of MRI.Methods A retrospective analysis of cardiac MR images in 22 patients after repair of CoA was performed.PWV was measured and calculated with phase contrast MRI,and echocardiography was performed to measure both ventricular function and myocardial thickness during the same period.Age and sex-matched 22 normal subjects were served as a control group and their aortic PWVs were measured.Results The averaged PWV in study group was significantly higher than that in control group [(4 .42 ± 3 .02 )m/s vs (2 .73 ± 0 .76 )m/s,P =0.02].In study group,the PWV value of children with moderate anastomotic stenosis was the highest. ROC curve analysis showed the highest sensitivity and specificity could be achieved to distinguish the mild or moderate anastomotic stenosis when the threshold for PWV was 3.37 m/s.No significant correlations were found between left ventricular end-diastolic volume,left ventricular end-systolic volume,ejection fraction,left ventricular thickness and PWV.Conclusion PWV is increased in children after repair of CoA.Significant aortic remodelling can be observed in patients with moderate anastomotic stenosis.

OBJECTIVETo design a kind of biomimetic polypeptide of dentin matrix protein-1 (DMP-1), which can bind to dentine collagen fibers and initiate mineralization.

METHODSA novel polypeptide was developed by connecting the collagen binding domain of DMP-1 "DSESSEEDR" to the hydrophilic C-terminal of amelogenin "TKREEVD". The polypeptide was synthetically prepared by standard solid-phase peptide synthesis. Human dentine slices were completely demineralized by hydrochloric acid to expose the dentine collagen. Fluorescein isothiocyanate coupled polypeptide was applied to the exposed dentine collagen. Fluorescent microscopy was used to examine the polypeptide specially bond to the dentine collagen. Nucleation and growth of hydroxyapatite was initiated by immersing the polypeptide into calcium chloride and sodium hypophosphate solutions respectively. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area diffraction (SAD) were used to examine the hydroxyapatites formed. RESULTS Fluorescent dentine collagen was identified in the demineralized dentine specimens. Nucleation and growth of crystals were detected after immersing the polypeptide into calcium chloride and sodium hypophosphate solutions by SEM and TEM. SAD confirmed the crystals were hydroxyapatites.

CONCLUSIONThe polypeptide of "DSESSEEDRTKREEVD" can simulate DMP-1 binding collagen and initiate hydroxyapatite nucleation and growth. It may be a potential molecular tool for dentine remineralization.

Biomimetics ; Calcium Phosphates ; Collagen ; Dentin ; Durapatite ; Humans ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Peptides