Differentiation of transforming growth factor β1-induced mesenchymal stem cells into nucleus pulposus-like cells under simulated microgravity conditions

This study aims to observe the differentiation effects of transforming growth factor β1 (TGF-β1)-transfected bone marrow mesenchymal stem cells (BMMSCs) into the nucleus pulposus-like cells under simulated microgravity conditions. BMMSCs were isolated from the adult rabbits, then cultured and proliferated to the third generation. After transfected by TGF-β1, these MMSCs were incubated in the calcium alginate gel microspheres and rotary cell culture system. The content changes of TGF-β1 inside BMMSCs, as well as the proliferation abilities of BMMSCs, were detected. The immunohistochemistry and toluidine blue staining were performed to detect the type II collagen. The RT-PCR method was performed to detect the expressions of proteoglycan and type II collagen mRNA. Results found that, on the 14th day, the polygonal nucleus pulposus-like cells could be observed. The TGF-β1 content inside the supernatant and the DNA content inside BMMSCs were significantly increased (P<0.05). The immunohistochemistry staining exhibited the positive results about the type II collagen. RT-PCR showed the expressions of proteoglycan and type II collagen mRNA inside BMMSCs. The TGF-β1-transfected BMSCs exhibited the increased synthesizing abilities of proteoglycan and type II collagen under simulated microgravity conditions than the control group.

Three novel single nucleotide polymorphisms of the 3-hydroxy-3-methylglutaryl coenzyme A reductase gene associated with egg-production in chicken

Different single-strand conformation polymorphism (SSCP) patterns of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) gene amplified by six pairs of primers were sequenced. Comparisons among the six nucleotide sequences of three genotypes revealed three base substitutions (G-789-A, C-937-G, and A-2316-C) in the HMGCR gene. The genotypes of single nucleotide polymorphism 1 (SNP1) and SNP3 were significantly associated with the number of eggs (P < 0.01), and the different genotypes of SNP2 did not significantly influence the number of eggs. The genotypes of all three SNPs were not related to the hatching rate of fertilized eggs (P > 0.05). Of the three SNPs of the HMGCR gene, those genotypes with lower plasma very low-density lipoprotein (VLDL) concentrations had higher egg production. The 300-day egg production of the six studied haplotypes showed three levels (P < 0.01). The ADE and ACE haplotypes showed lower egg production than the other haplotypes. The ADE haplotype had the highest plasma VLDL concentration, and the ACE haplotype had the lowest plasma VLDL concentration. We concluded that specific variants of the HMGCR gene are associated with chicken egg production, and haplotypes with higher and lower plasma VLDL concentrations showed lower egg production than other haplotypes.

Hydrothermal decomposition of potassium feldspar under alkaline conditions

For the first time, a transitional compound [Ca²⁺ ≡ 2AlSi₃O₈⁻ ≡ xOH⁻] was observed for K-feldspar hydrothermal alkaline decomposition, and a model was presented.

Correlation between gamma index passing rate and clinical dosimetric difference for pre-treatment 2D and 3D volumetric modulated arc therapy dosimetric verification

OBJECTIVE

To investigate comparatively the percentage gamma passing rate (%GP) of two-dimensional (2D) and three-dimensional (3D) pre-treatment volumetric modulated arc therapy (VMAT) dosimetric verification and their correlation and sensitivity with percentage dosimetric errors (%DE).

METHODS

%GP of 2D and 3D pre-treatment VMAT quality assurance (QA) with different acceptance criteria was obtained by ArcCHECK® (Sun Nuclear Corporation, Melbourne, FL) for 20 patients with nasopharyngeal cancer (NPC) and 20 patients with oesophageal cancer. %DE were calculated from planned dose-volume histogram (DVH) and patients' predicted DVH calculated by 3DVH® software (Sun Nuclear Corporation). Correlation and sensitivity between %GP and %DE were investigated using Pearson's correlation coefficient (r) and receiver operating characteristics (ROCs).

RESULTS

Relatively higher %DE on some DVH-based metrics were observed for both patients with NPC and oesophageal cancer. Except for 2%/2 mm criterion, the average %GPs for all patients undergoing VMAT were acceptable with average rates of 97.11% ± 1.54% and 97.39% ± 1.37% for 2D and 3D 3%/3 mm criteria, respectively. The number of correlations for 3D was higher than that for 2D (21 vs 8). However, the general correlation was still poor for all the analysed metrics (9 out of 26 for 3D 3%/3 mm criterion). The average area under the curve (AUC) of ROCs was 0.66 ± 0.12 and 0.71 ± 0.21 for 2D and 3D evaluations, respectively.

CONCLUSIONS

There is a lack of correlation between %GP and %DE for both 2D and 3D pre-treatment VMAT dosimetric evaluation. DVH-based dose metrics evaluation obtained from 3DVH will provide more useful analysis.

ADVANCES IN KNOWLEDGE

Correlation and sensitivity of %GP with %DE for VMAT QA were studied for the first time.

Assessment of the suitability of retroperitoneal laparoscopic ureterolithotomy as a treatment for complex proximal ureteral calculi

AIM

This retrospective study aimed to evaluate the suitability of retroperitoneal laparoscopic ureterolithotomy (RPLU) in the treatment of complex proximal ureteral calculi.

METHODS

Included were 24 patients who underwent RPLU for complex proximal ureteral stones from November 2008 to June 2010.

RESULTS

A retroperitoneal approach was performed in 23 patients with a mean operative time of 79.6 min (range of 65-130 min) and mean intraoperative blood loss of 20.1 mL (10-50 mL). No postoperative complications were encountered within during the follow-up period of 9.1 months (3-22 months). Only one patient who underwent RPLU within one week of failed ESWL was converted to open surgery due to severe adhesions around ureter and the injury of aberrant renal artery at the lower pole of left kidney encountered during the RPLU.

CONCLUSION

RPLU is safe and effective in the treatment of complex upper ureteral stones and can become a first-line surgical management of the disease.

Exoplanet detection. A terrestrial planet in a ~1-AU orbit around one member of a ~15-AU binary

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.