Establishment of a hepatic cirrhosis and portal hypertension model by hepatic arterial perfusion with 80% alcohol

AIM: To determine the feasibility and safety of establishing a porcine hepatic cirrhosis and portal hypertension model by hepatic arterial perfusion with 80% alcohol.

METHODS: Twenty-one healthy Guizhou miniature pigs were randomly divided into three experimental groups and three control groups. The pigs in the three experimental groups were subjected to hepatic arterial perfusion with 7, 12 and 17 mL of 80% alcohol, respectively, while those in the three control groups underwent hepatic arterial perfusion with 7, 12 and 17 mL of saline, respectively. Hepatic arteriography and direct portal phlebography were performed on all animals before and after perfusion, and the portal venous pressure and diameter were measured before perfusion, immediately after perfusion, and at 2, 4 and 6 wk after perfusion. The following procedures were performed at different time points: routine blood sampling, blood biochemistry, blood coagulation and blood ammonia tests before surgery, and at 2, 4 and 6 wk after surgery; hepatic biopsy before surgery, within 6 h after surgery, and at 1, 2, 3, 4 and 5 wk after surgery; abdominal enhanced computed tomography examination before surgery and at 6 wk after surgery; autopsy and multi-point sampling of various liver lobes for histological examination at 6 wk after surgery.

RESULTS: In experimental group 1, different degrees of hepatic fibrosis were observed, and one pig developed hepatic cirrhosis. In experimental group 2, there were cases of hepatic cirrhosis, different degrees of increased portal venous pressure, and intrahepatic portal venous bypass, but neither extrahepatic portal-systemic bypass circulation nor death occurred. In experimental group 3, two animals died and three animals developed hepatic cirrhosis, and different degrees of increased portal venous pressure and intrahepatic portal venous bypass were also observed, but there was no extrahepatic portal-systemic bypass circulation.

CONCLUSION: It is feasible to establish an animal model of hepatic cirrhosis and portal hypertension by hepatic arterial perfusion with 80% alcohol, however, the safety of this model depends on a suitable perfusion dose.

The Impact of Clinical Pharmacist Support on Patients Receiving Multi-drug Therapy for Coronary Heart Disease in China

The study determined pharmacist support on patients receiving multi-drug therapy for coronary heart disease by evaluating patient self-care ability, quality of life, and drug therapy compliance. In this study, ninety patients were randomly assigned to an experimental group (n=45) and a control group (n=45). The control group received conventional clinical care. The experimental group received clinical care plus pharmacist support that included medication review, patient education, lifestyle management, discharge guidance, and telephone follow-up. Eighty-five patients completed the study. Self-care ability and quality of life were evaluated before hospital discharge. The experimental group understood their condition better than the control group (P<0.05), the differences between the groups in understanding treatment goals, drug regimens, lifestyle modifications, psychogenic disorders, and satisfaction evaluations were more pronounced (P<0.01). At six-month follow-up, the difference between the groups in drug therapy compliance was P<0.01, as was success rate by intention-to-treat (77.8% vs. 48.9%) and per-protocol (81.4% vs. 52.4%). Two adverse drug reactions occurred in the experimental group and three in the control group. Pharmacist support improved self-care ability, quality of life, drug therapy compliance, and treatment success rate in coronary heart disease patients.

The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O(6+), 1.7 emA of Ar(8+), 1.07 emA of Ar(9+), and 118 euA of Bi(28+). The source has also successfully delivered O(5+) and Ar(8+) ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

Application of renal-rotation techniques in retroperitoneoscopic partial nephrectomy

Retroperitoneoscopic partial nephrectomy (RPN) is one of the standard methods for treating T1-stage renal carcinoma, which has a narrow operational space and a difficult surgical procedure. The aim of this study was to examine the safety and feasibility of renal-rotation techniques in RPN. Between April 2012 and June 2014, the renal-rotation technique in RPN was performed in 22 male and 16 female patients, aged between 31 and 75 years (mean, 52 years), with stage T1N0M0 renal-cell carcinoma. In 29 cases the tumor was located at the ventral side of the kidney, including 22 cases at the renal hilum, and in nine cases the tumor was located at the inferior pole of the kidney. The tumor size was between 1.5 and 4.6 cm (mean, 2.8 cm). The results showed that, in all 38 cases, the procedure was successfully accomplished without conversion to open surgery. There were no intraoperative complications and only three cases of postoperative complications. The surgery duration was between 45 and 116 min (mean, 59 min); blood loss was between 10 and 120 ml (mean, 40 ml) and no patients required a blood transfusion. The average kidney ischemia time was 21 min (range, 15–38 min). No patients had local recurrence or metastasis after follow-up of between one and 26 months. In conclusion, the application of the renal-rotation technique in RPN for tumors located at the ventral side, renal hilum or at the inferior pole of the kidney is safe and feasible and worth wider clinical application.

Transjugular intrahepatic portosystemic shunt for severe jaundice in patients with acute Budd-Chiari syndrome

AIM: To evaluate the feasibility of transjugular intrahepatic portosystemic shunt (TIPS) for severe jaundice secondary to acute Budd-Chiari syndrome (BCS).

METHODS: From February 2009 to March 2013, 37 patients with severe jaundice secondary to acute BCS were treated. Sixteen patients without hepatic venule, hepatic veins (HV) obstruction underwent percutaneous angioplasty of the inferior vena cava (IVC) and/or HVs. Twenty-one patients with HV occlusion underwent TIPS. Serum bilirubin, liver function, demographic data and operative data of the two groups of patients were analyzed.

RESULTS: Twenty-one patients underwent TIPS and the technical success rate was 100%, with no technical complications. Sixteen patients underwent recanalization of the IVC and/or HVs and the technical success rate was 100%. The mean procedure time for TIPS was 84.0 ± 12.11 min and angioplasty was 44.11 ± 5.12 min (P < 0.01). The mean portosystemic pressure in the TIPS group decreased significantly from 40.50 ± 4.32 to 16.05 ± 3.50 mmHg (P < 0.01). The mean portosystemic pressure gradient decreased significantly from 33.60 ± 2.62 to 7.30 ± 2.21 mmHg (P < 0.01). At 8 wk after the procedures, in the TIPS group, total bilirubin (TBIL) decreased significantly from 266.24 ± 122.03 before surgery to 40.11 ± 3.52 μmol/L (P < 0.01) and direct bilirubin (DBIL) decreased significantly from 194.22 ± 69.82 μmol/L to 29.82 ± 3.10 μmol/L (P < 0.01). In the angioplasty group, bilirubin returned to the normal range, with TBIL decreased significantly from 258.22 ± 72.71 μmol/L to 13.33 ± 3.54 μmol/L (P < 0.01) and DBIL from 175.08 ± 39.27 to 4.03 ± 1.74 μmol/L (P < 0.01). Liver function improved faster than TBIL. After 2 wk, in the TIPS group, alanine aminotransferase (ALT) decreased significantly from 50.33 ± 40.61 U/L to 28.67 ± 7.02 U/L (P < 0.01) and aspartate aminotransferase (AST) from 49.46 ± 34.33 U/L to 26.89 ± 8.68 U/L (P < 0.01). In the angioplasty group, ALT decreased significantly from 51.56 ± 27.90 to 14.22 ± 2.59 μmol/L (P < 0.01) and AST from 60.66 ± 39.89 μmol/L to 8.18 ± 1.89 μmol/L (P < 0.01). After mean follow-up of 12.6 mo, there was no recurrence of jaundice in either group.

CONCLUSION: Severe jaundice is not a contraindication for TIPS in patients with acute BCS and TIPS is appropriate for severe jaundice due to BCS.

Altered iPSC-derived neurons' sodium channel properties in subjects with Monge's disease

Monge's disease, also known as chronic mountain sickness (CMS), is a disease that potentially threatens more than 140 million highlanders during extended time living at high altitudes (over 2500m). The prevalence of CMS in Andeans is about 15-20%, suggesting that the majority of highlanders (non-CMS) are rather healthy at high altitudes; however, CMS subjects experience severe hypoxemia, erythrocytosis and many neurologic manifestations including migraine, headache, mental fatigue, confusion, and memory loss. The underlying mechanisms of CMS neuropathology are not well understood and no ideal treatment is available to prevent or cure CMS, except for phlebotomy. In the current study, we reprogrammed fibroblast cells from both CMS and non-CMS subjects' skin biopsies into the induced pluripotent stem cells (iPSCs), then differentiated into neurons and compared their neuronal properties. We discovered that CMS neurons were much less excitable (higher rheobase) than non-CMS neurons. This decreased excitability was not caused by differences in passive neuronal properties, but instead by a significantly lowered Na(+) channel current density and by a shift of the voltage-conductance curve in the depolarization direction. Our findings provide, for the first time, evidence of a neuronal abnormality in CMS subjects as compared to non-CMS subjects, hoping that such studies can pave the way to a better understanding of the neuropathology in CMS.

Jaridonin-induced G2/M phase arrest in human esophageal cancer cells is caused by reactive oxygen species-dependent Cdc2-tyr15 phosphorylation via ATM-Chk1/2-Cdc25C pathway

Jaridonin, a novel diterpenoid from Isodon rubescens, has been shown previously to inhibit proliferation of esophageal squamous cancer cells (ESCC) through G2/M phase cell cycle arrest. However, the involved mechanism is not fully understood. In this study, we found that the cell cycle arrest by Jaridonin was associated with the increased expression of phosphorylation of ATM at Ser1981 and Cdc2 at Tyr15. Jaridonin also resulted in enhanced phosphorylation of Cdc25C via the activation of checkpoint kinases Chk1 and Chk2, as well as in increased phospho-H2A.X (Ser139), which is known to be phosphorylated by ATM in response to DNA damage. Furthermore, Jaridonin-mediated alterations in cell cycle arrest were significantly attenuated in the presence of NAC, implicating the involvement of ROS in Jaridonin's effects. On the other hand, addition of ATM inhibitors reversed Jaridonin-related activation of ATM and Chk1/2 as well as phosphorylation of Cdc25C, Cdc2 and H2A.X and G2/M phase arrest. In conclusion, these findings identified that Jaridonin-induced cell cycle arrest in human esophageal cancer cells is associated with ROS-mediated activation of ATM-Chk1/2-Cdc25C pathway.

Transverse coupling property of beam from ECR ion sources

Experimental evidence of the property of transverse coupling of beam from Electron Cyclotron Resonance (ECR) ion source is presented. It is especially of interest for an ECR ion source, where the cross section of extracted beam is not round along transport path due to the magnetic confinement configuration. When the ions are extracted and accelerated through the descending axial magnetic field at the extraction region, the horizontal and vertical phase space strongly coupled. In this study, the coupling configuration between the transverse phase spaces of the beam from ECR ion source is achieved by beam back-tracking simulation based on the measurements. The reasonability of this coupling configuration has been proven by a series of subsequent simulations.

Parallel transjugular intrahepatic portosystemic shunt for controlling portal hypertension complications in cirrhotic patients

AIM: To evaluate the feasibility of a second parallel transjugular intrahepatic portosystemic shunt (TIPS) to reduce portal venous pressure and control complications of portal hypertension.

METHODS: From January 2011 to December 2012, 10 cirrhotic patients were treated for complications of portal hypertension. The demographic data, operative data, postoperative recovery data, hemodynamic data, and complications were analyzed.

RESULTS: Ten patients underwent a primary and parallel TIPS. Technical success rate was 100% with no technical complications. The mean duration of the first operation was 89.20 ± 29.46 min and the second operation was 57.0 ± 12.99 min. The mean portal system pressure decreased from 54.80 ± 4.16 mmHg to 39.0 ± 3.20 mmHg after the primary TIPS and from 44.40 ± 3.95 mmHg to 26.10 ± 4.07 mmHg after the parallel TIPS creation. The mean portosystemic pressure gradient decreased from 43.80 ± 6.18 mmHg to 31.90 ± 2.85 mmHg after the primary TIPS and from 35.60 ± 2.72 mmHg to 15.30 ± 3.27 mmHg after the parallel TIPS creation. Clinical improvement was seen in all patients after the parallel TIPS creation. One patient suffered from transient grade I hepatic encephalopathy (HE) after the primary TIPS and four patients experienced transient grade I-II after the parallel TIPS procedure. Mean hospital stay after the first and second operations were 15.0 ± 3.71 d and 16.90 ± 5.11 d (P = 0.014), respectively. After a mean 14.0 ± 3.13 mo follow-up, ascites and bleeding were well controlled and no stenosis of the stents was found.

CONCLUSION: Parallel TIPS is an effective approach for controlling portal hypertension complications.

Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole

The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C(6+) beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

Individuals having variant genotypes of cytochrome P450 2C19 are at increased risk of developing primary liver cancer in Han populations, without infection with the hepatitis virus

Recently, many researchers have reported that the genetic polymorphisms of CYP2C19 may account for the interpatient variability of the clinical course in cancers including primary liver cancer (PLC). Besides the genetic polymorphisms of CYP2C19, hepatitis viruses (HV, including HAV, HBV, HCV, HDV, HEV, especially HBV and/or HCV) also account for the interpatient variability of the clinical course in PLC. This research covered the above two factors and divided the patients with PLC into two groups (one group with HBV infection and another without any HV infection) to find out whether the genetic polymorphisms of CYP2C19 have different effects in the progressing of PLC in different groups of patients. Eight hundred sixty-four cancer-free Han people (controls, named group 1), 207 Han PLC patients with HBV infection (group 2), and 55 Han PLC patients without any HV infection (group 3) were involved in this study. A wild-type allele (CYP2C19*1) and two mutated alleles (CYP2C19*2 and CYP2C19*3) were identified. The frequencies of the mutant alleles and genotypes were then compared with each other. The frequencies of the homozygous and heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) in group 3 (25.5 %) were significantly higher than those in other groups (11.9 % in group 1 and 13.5 % in group 2, P = 0.014, 95 % confidence interval (CI)). The differences were statistically significant between group 1 and group 3 (P = 0.004, 95 % CI), but they were not statistically significant between group 1 and group 2 (P = 0.527, 95 % CI). Thus, we conclude that people which were not infected with HV but with the homozygous or heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) of CYP2C19 may have higher possibilities of getting PLC than people with other allelic genotypes (*1/*1, *1/*2, *1/*3) (odds ratio (OR) = 2.523, 95 % CI = 1.329 ~ 4.788). However, in patients with HBV infection, the genetic polymorphisms of CYP2C19 did not seem to be an important factor in the risk of developing PLC (OR = 1.156, 95 % CI = 0.738 ~ 1.810).

Immunoregulatory activities of Dendrobium huoshanense polysaccharides in mouse intestine, spleen and liver

To evaluate the immunomodulating responses in intestine, spleen and liver, 50-200mg/kg of DHP was orally administrated to mice without or with methotrexate. The proliferation of marrow cells, which was performed with the addition of the supernatant of small intestinal lymphocytes isolated from the mice administrated orally with DHP, showed that the intestinal immune response was significantly enhanced in all DHP-treated groups. For the immune response in spleen, all tested doses of DHP remarkably promoted the proliferation of splenic cells and increased the secretion of interferon-γ (IFN-γ). For the immune responses in liver, DHP not only significantly stimulated the proliferation of hepatic cells and the secretion of IFN-γ at all tested doses of DHP, but also significantly elevated the secretion interleukin-4 (IL-4) at the doses of 100 and 200mg/kg. Moreover, DHP could recover methotrexate-injured small intestinal immune function (100 and 200mg/kg) and promoted cell proliferation and IFN-γ production (200mg/kg) in spleen and liver of methotrexate-treated mice. These results suggested that DHP after oral administration possessed immunomodulating effects both in small intestine immune system and in systemic immune system, which were further proved by the mRNA expression of IFN-γ and IL-4.

Study on space charge effect in an electrostatic ion analyzer applied to measure laser produced ions

The abundance of different ions produced by laser ion sources is usually analyzed by an electrostatic ion analyzer (EIA). Ion current intensities in the range of several mA/cm(2) at the position of the EIA have been achieved from the laser ion source developed by the Institute of Modern Physics; this indicates that a noticeable influence of space charge effect during the ion transmission will occur. Hence, while the parameters of the EIA or the beams are changed, such as ion species, current intensity, the ions' transmission efficiency through the EIA is different, which will result in an uncertainty in the estimation of the ions' yields. Special attention is focused on this issue in this paper. Ion's transmissions through the EIA under different circumstances are studied with simulations and experiments, the results of which are consistent with each other.

The study towards high intensity high charge state laser ion sources

As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

Study on a negative hydrogen ion source with hot cathode arc discharge

A negative hydrogen (H(-)) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H(-) beam with ɛ N, RMS = 0.08 π mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I(e(-))/I(H(-)) were experimentally studied. The discussion on the result, and opinions to improve the source were given.

Application of evaporative cooling technology in super-high power density magnet

Evaporative cooling technology utilizes phase-change heat transfer mode to achieve the cooling for heating equipment. The heat transfer capacity of evaporative cooling technology is far more than air or water cooling technology. The Electron Cyclotron Resonance ion source magnet is a typical super-high power density magnet, and the evaporative cooling technology is an ideal cooling method for the coils of magnet. In this paper we show the structure and process of coils and the special design of flow channels of coolant for an experiment magnet model. Additionally, the heat transfer circulation is presented and analyzed. By the finite element method, the flow channels are optimized to rationally allocate coolant and to reduce the temperature of coils. For the experiment model, the current density of copper wire of coils is 19 A/mm(2), and the coil-windows current density is larger than 12 A/mm(2). The max temperature of coils is below 80 °C, and the total heat is about 200 kW.

Progress of a room temperature electron cyclotron resonance ion source using evaporative cooling technology at Institute of Modern Physics

A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.0-1.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper.

A 2.45 GHz intense proton source and low energy beam transport system for China Initiative Accelerator Driven Sub-Critical reactor system

At Institute of Modern Physics, a cw 35 keV, 20 mA intense proton source and the low energy beam transport system (LEBT) have been developed for China Initiative Accelerator Driven Sub-Critical reactor system. In order to ensure high quality transmission of the intense ion beam from the exit of ion source to Radio Frequency Quadrupole (RFQ), a low energy beam transport line is used to focus beam to the RFQ entrance and match the Twiss parameters to the RFQ requirements. The 35 keV, 20 mA ion beam extracted by a three-electrode extraction system from the ion source passes through the LEBT to the RFQ entrance and the root-mean-square emittance is measured to be less than 0.2 π mm mrad. The commissioning results of the ion source and low energy beam transport system are described in this paper. The beam quality and transmission efficiency are also studied.

Studies on low energy beam transport for high intensity high charged ions at IMP

Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18-24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper.

Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP)

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R&D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe(27+), 236 eμA Xe(30+), and 64 eμA Xe(35+). Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi(30+) and 202 eμA U(33+) have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.

Prognostic and predictive value of a microRNA signature in stage II colon cancer: a microRNA expression analysis

BACKGROUND

Current staging methods do not accurately predict the risk of disease recurrence and benefit of adjuvant chemotherapy for patients who have had surgery for stage II colon cancer. We postulated that expression patterns of multiple microRNAs (miRNAs) could, if combined into a single model, improve postoperative risk stratification and prediction of chemotherapy benefit for these patients.

METHOD

Using miRNA microarrays, we analysed 40 paired stage II colon cancer tumours and adjacent normal mucosa tissues, and identified 35 miRNAs that were differentially expressed between tumours and normal tissue. Using paraffin-embedded specimens from a further 138 patients with stage II colon cancer, we confirmed differential expression of these miRNAs using qRT-PCR. We then built a six-miRNA-based classifier using the LASSO Cox regression model, based on the association between the expression of every miRNA and the duration of individual patients' disease-free survival. We validated the prognostic and predictive accuracy of this classifier in both the internal testing group of 138 patients, and an external independent group of 460 patients.

FINDINGS

Using the LASSO model, we built a classifier based on the six miRNAs: miR-21-5p, miR-20a-5p, miR-103a-3p, miR-106b-5p, miR-143-5p, and miR-215. Using this tool, we were able to classify patients between those at high risk of disease progression (high-risk group), and those at low risk of disease progression (low-risk group). Disease-free survival was significantly different between these groups in every set of patients. In the initial training group of patients, 5-year disease-free survival was 89% (95% CI 77·3-94·4) for the low-risk group, and 60% (46·3-71·0) for the high-risk group (hazard ratio [HR] 4·24, 95% CI 2·13-8·47; p<0·0001). In the internal testing set of patients, 5-year disease-free survival was 85% (95% CI 74·3-91·8) for the low-risk group, and 57% (42·8-68·5) for the high-risk group (HR 3·63, 1·86-7·01; p<0·0001), and in the independent validation set of patients, was 85% (79·6-89·0) for the low-risk group and 54% (46·4-61·1) for the high-risk group (HR 3·70, 2·56-5·35; p<0·0001). The six-miRNA-based classifier was an independent prognostic factor for, and had better prognostic value than, clinicopathological risk factors and mismatch repair status. In an ad-hoc analysis, the patients in the high-risk group were found to have a favourable response to adjuvant chemotherapy (HR 1·69, 1·17-2·45; p=0·0054). We developed two nomograms for clinical use that integrated the six-miRNA-based classifier and four clinicopathological risk factors to predict which patients might benefit from adjuvant chemotherapy after surgery for stage II colon cancer.

CONCLUSION

Our six-miRNA-based classifier is a reliable prognostic and predictive tool for disease recurrence in patients with stage II colon cancer, and might be able to predict which patients benefit from adjuvant chemotherapy. It might facilitate patient counselling and individualise management of patients with this disease.

FUNDING

Natural Science Foundation of China.

Note: investigation on the influences of gripping methods on elastic modulus by a miniature tensile device and in situ verification

In this paper, by gripping the specimen on various positions, including the gripping section, stress concentration transition section, and gauge length section, theoretical analysis on the influences of gripping methods on tensile elastic modulus calculation was investigated with a group of equations. Then, an image-based displacement measurement system was implemented, and the experimental verification via in situ tensile testing was carried out to verify the feasibility of the theoretical analysis by a miniature tensile device integrated with a metallographic microscope. The stress-strain curves of 2026 aluminum alloy were also obtained by gripping the specimens on various positions to illustrate the influences of gripping methods. The influence of gripping methods on elongation measurement was also investigated. This paper showed a modular calculation method of elastic modulus for the tensile testing of typical plate specimens.