Meta-analysis of outcomes compared between robotic and laparoscopic gastrectomy for gastric cancer

This meta-analysis was performed to evaluate and compare the outcomes of robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) for treating gastric cancer. A systematic literature search was carried out using the PubMed database, Web of Knowledge, and the Cochrane Library database to obtain comparative studies assessing the safety and efficiency between RG and LG in May, 2013. Data of interest were analyzed by using of Review Manager version 5.2 software (Cochrane Collaboration). A fixed effects model or random effects model was applied according to heterogeneity. Seven papers reporting results that compared robotic gastrectomy with laparoscopic gastrectomy for gastric cancer were selected for this meta-analysis. Our meta- analysis included 2,235 patients with gastric cancer, of which 1,473 had undergone laparoscopic gastrectomy, and 762 had received robotic gastrectomy. Compared with laparoscopic gastrectomy, robotic gastrectomy was associated with longer operative time but less blood loss. There were no significant difference in terms of hospital stay, total postoperative complication rate, proximal margin, distal margin, numbers of harvested lymph nodes and mortality rate between robotic gastrectomy and laparoscopic gastrectomy. Our meta-analysis showed that robotic gastrectomy is a safe technique for treating gastric cancer that compares favorably with laparoscopic gastrectomy in short term outcomes. However, the long term outcomes between the two techniques need to be further examined.

A functional variant in microRNA-196a2 is associated with susceptibility of colorectal cancer in a Chinese population

BACKGROUND AND AIMS

MicroRNAs (miRNA) can act as oncogenes or tumor suppressors. Polymorphisms present in pri-, pre- and mature miRNAs can potentially modulate the expression of hundreds of genes, broadly affecting miRNA function. Notably, the rs11614913 SNP in miR-196a2 has been implicated in carcinogenesis, but its association with colorectal cancer (CRC) remains unexplored. We performed a case-control study to investigate the genetic association between this functional SNP and CRC susceptibility and progression.

METHODS

We genotyped the rs11614913 SNP in 252 CRC patients and 543 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In addition, we examined miR-196a expression level in colorectal cancer tissues (n = 50) obtained from the studied CRC patients.

RESULTS

Frequency of the CC genotype was higher in CRC patients than controls, implying that the subjects with the CC genotype or C allele containing genotypes (CT and CC) have a higher risk of CRC. However, no significant association between this polymorphism and CRC progression was observed. Expression analysis revealed that rs11614913 CC or carrying at least one C allele was associated with a significantly increased level of mature miR-196a (p = 0.010 or = 0.022).

CONCLUSIONS

The present study provides the first evidence that miR-196a2 polymorphism may contribute to CRC susceptibility in a Chinese population through modulating mature miR-196a expression.

Pharmacological inhibition of AKT sensitizes MCF-7 human breast cancer-initiating cells to radiation

BACKGROUND

Caner-initiating cells (CICs or cancer stem cells) have been shown both experimentally and clinically to be resistant to radiation. The mechanism underlying radioresistance remains unclear.

METHODS

In the present study, we screened 51 genes which are potentially important in mediating radioresistance of breast CICs.

RESULTS

The expression of AKT1 and AKT2 at protein and mRNA levels was dramatically increased among the screened genes by 8 Gy radiation treatment in MCF-7 mammosphere cells (predominantly CD24(-/low)/CD44(+) CICs), but not in the bulk population of MCF-7 cells (predominantly CD24(+)/CD44(+)). Using apoptosis and clonogenic survival assays, we found pharmacological inhibition of AKT with selective inhibitors of AKT sensitized MCF-7 mammosphere cells, but not MCF-7 monolayer cells to radiation.

CONCLUSION

The present findings suggest that treatment with AKT inhibitors prior to ionizing radiation treatment may be a potential benefit to patients with breast cancer, in particular to eradiate breast CICs.

STAT1 promotes radioresistance of CD44(+)/CD24(-/low) cells in breast cancer

Breast cancer-initiating cells are a relatively radioresistant subpopulation of breast cancer cells. However, the mechanism of this radioresistance is still unclear. This study aimed to investigate the effect of radiation on the levels of signal transducer and activator of transcription 1 (STAT1) in mammospheres of cancer-initiating cells and monolayer cultures of MCF-7 cells. We isolated CD44(+)/CD24(-/low) cancer-initiating cells from MCF-7 cells and propagated them as mammospheres. Next we used realtime quantitative reverse-transcriptase polymerase chain reaction to examine the mRNA level of STAT1 in mammospheres of breast cancer-initiating cells and monolayer cultures of MCF-7 cells. The apoptosis rate and surviving fraction using clonogenic assays was observed after treating the cells with a STAT1 inhibitor. After irradiation, the STAT1 level in the mammospheres was higher than that in the monolayer cultures. STAT1 inhibitor treatment did not cause significant changes in the apoptosis rate and surviving fraction in the MCF-7 monolayer cultures. However, the inhibitor treatment caused significant differences in the apoptosis rate and surviving fraction in mammospheres. Our study provides the first evidence that STAT1 signaling contributes to radioresistance in breast cancer-initiating cells and reveals STAT1 as a promising target to reduce radioresistance and enhance the efficacy of radiotherapy for breast cancer.

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China

OBJECTIVE

To test the efficacy of locally produced Vi vaccine over a time period of longer than one year.

METHODS

A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests).

FINDINGS

After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries.

CONCLUSION

The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Evaporation of Accretion Disks around Black Holes: The Disk-Corona Transition and the Connection to the Advection-dominated Accretion Flow

We apply the disk-corona evaporation model (Meyer & Meyer-Hofmeister) originally derived for dwarf novae to black hole systems. This model describes the transition of a thin cool outer disk to a hot coronal flow. The mass accretion rate determines the location of this transition. For a number of well-studied black hole binaries, we take the mass flow rates derived from a fit of the advection-dominated accretion flow (ADAF) model to the observed spectra (for a review, see Narayan, Mahadevan, & Quataert) and determine where the transition of accretion via a cool disk to a coronal flow/ADAF would be located for these rates. We compare this with the observed location of the inner disk edge, as estimated from the maximum velocity of the Halpha emission line. We find that the transition caused by evaporation agrees with this determination in stellar disks. We also show that the ADAF and the "thin outer disk + corona" are compatible in terms of the physics in the transition region.

The cardiovascular response to medullary cholinergic and corticoid stimulation is calcium channel dependent in rats

Experiments were performed on anaesthetized Wistar or Sprague-Dawley rats of both sexes. Microinjection of an acetylcholinesterase inhibitor physostigmine (0.4 microgram/0.1 microliter/site) or acetylcholine (ACh, 25 ng/0.1 microliter/site) into the rostral ventrolateral medulla (rVLM) caused an increase in blood pressure (BP), heart rate (HR) and the pressor response produced by stimulation of the dorsal periaqueductal grey (dPAG) in the midbrain. Prior microinjection of the calcium channel blocker verapamil (0.25 microgram/0.1 microliter/site) into the same sites blocked the cardiovascular effect in response to the respective microinjection of the drugs mentioned above. Moreover, verapamil pretreatment blocked the pressor and tachycardiac effect induced by respective microinjection of corticosterone (40 ng/0.1 microliter/site) or aldosterone (40 ng/0.1 microliter/site) into the rVLM, as well as the enhancement of the pressor response to stimulation of the dPAG induced by microinjection of corticoids into the rVLM. These results suggest that the enhancement of cardiovascular activities mediated by cholinergic mechanisms may be due to the activation of postsynaptic calcium channels of neurons in the rVLM. The corticosteroid effect seems to be mediated by similar mechanisms.