Sustained release silicon from 3D bioprinting scaffold using silk/gelatin inks to promote osteogenesis.

Repairing extensive bone defects that cannot self-heal has been a clinical challenge. The construction of scaffolds with osteogenic activity through tissue engineering can provide an effective strategy for bone regeneration. This study utilized gelatin, silk fibroin, and Si3N4 as scaffold materials to prepare silicon-functionalized biomacromolecules composite scaffolds using three-dimensional printing (3DP) technology. This system delivered positive outcomes when Si3N4 levels were 1 % (1SNS). The results showed that the scaffold had a porous reticular structure with a pore size of 600-700 µm. The Si3N4 nanoparticles were distributed uniformly in the scaffold. The scaffold could release Si ions for up to 28 days. In vitro experiments showed that the scaffold had good cytocompatibility, promoting the osteogenic differentiation of mesenchymal stem cells (MSCs). In vivo experiments on bone defects in rats showed that the 1SNS group facilitated bone regeneration. Therefore, the composite scaffold system showed potential for application in bone tissue engineering.

Prevalence and risk factors of intracranial vertebrobasilar artery stenosis in a southern Chinese population: a cross-sectional study by transcranial Doppler / 中华神经科杂志

Objective To investigate the prevalence and risk factors of intracranial vertebrobasilar artery stenosis. Methods By cluster sampling, adult Han people were recruited from residential communities. Medical history was documented and body height, body weight, waist circumference, hip circumference and blood pressure were measured. Venous blood samples were collected to determine serum fasting glucose, total cholesterol and triglycerides concentrations. Intracranial vertebrobasilar artery stenosis was diagnosed with transcranial Doppler. The SPSS 11.0 software package was used for data analysis. Results Among 1035 people conforming to the inclusion criteria, intracranial vertebrobasilar artery stenosis was found in 58 (5.6%), 17 with left VA stenosis, 23 with right VA stenosis and 30 with BA stenosis.Univariate analysis showed that subjects with diabetes mellitus had a significantly higher prevalence ( 10. 3% ) of intracranial vertebrobasilar artery stenosis (χ2 = 6. 221, P = 0. 013 ) and the mean systolic blood pressure (( 131.1 ± 25.5) mm Hg, 1 mm Hg = 0. 133 kPa) in the subjects with stenosis was significantly higher than those without (3.2%, ( 124. 1 ± 21.6) mm Hg) (t = 2. 228, P = 0. 026). Logistic regression indicated that diabetes mellitus and systolic blood pressure were independent risk factors for intracranial vertebrobasilar artery stenosis ( diabetes mellitus: OR = 3. 305, P = 0. 023; elevated systolic blood pressure 1 mm Hg: OR = 1. 012, P =0. 047). Conclusions This study demonstrated a considerably high prevalence of intracranial vertebrobasilar artery stenosis in a southern Chinese population. Diabetes mellitus and systolic blood pressure play potent roles in intracranial vertebrobasilar artery stenosis.