Zhihai Peng

Spline-Kernelled Chirplet Transform for the Analysis of Signals With Time-Varying Frequency and Its Application

The conventional time-frequency analysis (TFA) methods, including continuous wavelet transform, short-time Fourier transform, and Wigner-Ville distribution, have played important roles in analyzing nonstationary signals. However, they often show less capability in dealing with nonstationary signals with time-varying frequency due to the bad energy concentration in the time-frequency plane. On the other hand, by introducing an extra transform kernel that matches the instantaneous frequency of the signal, parameterized TFA methods show powerful ability in characterizing time-frequency patterns of nonstationary signals with time-varying frequency. In this paper, a novel time-frequency transform, called spline-kernelled chirplet transform (SCT), is proposed. By introducing a frequency-rotate operator and a frequency-shift operator constructed with spline kernel function, the SCT is particularly powerful for the strongly nonlinear frequency-modulated signals. In addition, an effective algorithm is developed to estimate the parameters of transform kernel in the SCT. The capabilities of the SCT and parameter estimation algorithm are validated by their applications for numerical signals and a set of vibration signal collected from a rotor test rig.

MicroRNA-20a-5p promotes colorectal cancer invasion and metastasis by downregulating Smad4

Background Tumor metastasis is one of the leading causes of poor prognosis for colorectal cancer (CRC) patients. Loss of Smad4 contributes to aggression process in many human cancers. However, the underlying precise mechanism of aberrant Smad4 expression in CRC development is still little known. Results miR-20a-5p negatively regulated Smad4 by directly targeting its 3′UTR in human colorectal cancer cells. miR-20a-5p not only promoted CRC cells aggression capacity in vitro and liver metastasis in vivo, but also promoted the epithelial-to-mesenchymal transition process by downregulating Smad4 expression. In addition, tissue microarray analysis obtained from 544 CRC patients’ clinical characters showed that miR-20a-5p was upregulated in human CRC tissues, especially in the tissues with metastasis. High level of miR-20a-5p predicted poor prognosis in CRC patients. Methods Five miRNA target prediction programs were applied to identify potential miRNA(s) that target(s) Smad4 in CRC. Luciferase reporter assay and transfection technique were used to validate the correlation between miR-20a-5p and Smad4 in CRC. Wound healing, transwell and tumorigenesis assays were used to explore the function of miR-20a-5p and Smad4 in CRC progression in vitro and in vivo. The association between miR-20a-5p expression and the prognosis of CRC patients was evaluated by Kaplan–Meier analysis and multivariate cox proportional hazard analyses based on tissue microarray data. Conclusions miR-20a-5p, as an onco-miRNA, promoted the invasion and metastasis ability by suppressing Smad4 expression in CRC cells, and high miR-20a-5p predicted poor prognosis for CRC patients, providing a novel and promising therapeutic target in human colorectal cancer.

miR-181a-5p promotes the progression of gastric cancer via RASSF6-mediated MAPK signalling activation

We previously discovered that Ras association domain family member 6 (RASSF6) was downregulated and predicted poor prognosis in GC patients. However, the mechanisms of the down regulation of RASSF6 in GC remained unclear. Increasing evidence indicates that dysregulation of microRNAs promotes the progression of cancer through the repression of tumour suppressors. Here, we identified miR-181a-5p as a novel regulator of RASSF6 in GC. Functionally, ectopic expression or silencing of miR-181a-5p, respectively, promoted or inhibited GC cell proliferation, colony formation and cell cycle transition, as well as enhanced or prevented the invasion, metastasis of GC cells and epithelial to mesenchymal transition of GC cells inxa0vitro and inxa0vivo. Molecularly, miR-181a-5p functioned as an onco-miRNA by activating the RASSF6-regulated MAKP pathway. Overexpression or silencing of RASSF6 could partially reverse the effects of the overexpression or repression of miR-181a-5p on GC progress caused by activation of the MAKP pathway inxa0vitro and inxa0vivo. Clinically, high miR-181a-5p expression predicted poor survival in GC patients, especially combined with low RASSF6 expression. Collectively, we identified miR-181a-5p as an onco-miRNA, which acts by directly repressing RASSF6 in GC.

The TM6SF2 rs58542926 T allele is significantly associated with non-alcoholic fatty liver disease in Chinese

To the Editor: A recent study has identified that a missense variant in TM6SF2 gene (rs58542926: C>T, NP_001001524.2:p. E167K) is significantly associated with non-alcoholic fatty liver disease (NAFLD) [1]. Further analyses suggested that this variant is also significantly associated with NAFLD disease progression [2,3]. However, most of the studies thus far were performed in nonAsian populations, leaving out the question as to whether this variant also confers a risk of NAFLD in Asians (particularly East Asians), the largest population in the world. A most recent study led by Wong and colleagues examined the impact of TM6SF2 variant on NAFLD in a Chinese cohort, where the TM6SF2 167K allele was concluded to have a limited effect on NAFLD [4]. This was deemed to be attributed to the low minor allele frequency (MAF = 7% in their study) as well as the confounding effect of the PNPLA3 I148M variant, another significant risk factor for NAFLD that are replicated among all major human populations [5]. In order to further verify the effect of this newly discovered allele in NAFLD, we conducted a case-control study in a community-based Han Chinese population. The rs58542926 polymorphism was genotyped in blood DNA samples from NAFLD patients (n = 384) and healthy controls (n = 384) that were collected in the health examination center of Shanghai Jiao Tong University Affiliated First People’s Hospital (Shanghai, China). Genotyping was conducted using a Taqman-based assay (Life Technologies, CA, USA). Both the case and control groups consisted of 229 males and 155 females, with a mean age of 45 ± 13 years. The NAFLD diagnosis was made based on ultrasonographic examinations according to the guideline defined by the Chinese National Consensus Workshop on NAFLD [6]. The examination was performed by one experienced operator who was blinded to both clinical and biochemical evaluations of the patients. No histological data based on liver biopsy were available for these patients. For each individual, detailed data for ultrasonographic examination of the upper abdominal organs, clinical data for a comprehensive physical examination as well as a questionnaire for demographic, disease history, family history, smoking and alcohol intake information were all collected. The NAFLD patients were selected by excluding the cases with other known causes of steatosis, including heavy alcohol intake (>20 g/day), the use of medications known to contribute to hepatic steatosis, and hepatitis B and C virus infection. Patients with a high likelihood to have other known liver diseases were also excluded. Randomly selected healthy volunteers from the same population with normal liver enzymes, liver ultrasound and without any major illnesses were chosen as controls. The cases and controls were 1:1 matched according to their gender and age information. All enrolled individuals are self-reported Han Chinese and reside in the Shanghai metropolitan area. Informed consent was obtained from all participants. The study was approved by the ethical committees of the Shanghai Jiao Tong University and strictly conforms to the principles of the Declaration of Helsinki. Consistent with Wong’s results, the TM6SF2 167K allele has a similarly low frequency in our dataset (MAF = 6.6%). However, we still observed a significant association between TM6SF2 167K allele and NAFLD (p = 0.0007) after adjustment for age, sex, body mass index and status of diabetes (Table 1). Furthermore, to clarify the independent effect of the TM6SF2 allele on NAFLD, we controlled the PNPLA3 rs738409 polymorphism, which was significantly associated with NAFLD in our data (p = 0.0002, data not shown). Our analysis showed that rs58542926 remained to be associated with NAFLD (p = 0.0004) after conditioning on rs738409 (Table 1). Moreover, several genome-wide association studies have shown that a variant in NCAN (rs2228603), whose locus is near TM6SF2, is strongly associated with NAFLD [7,8]. However, rs2228603 is not significantly associated with NAFLD in our samples (p = 0.1, data not shown). After conditioning on this variant, the TM6SF2 rs58542926 variant still remains significant (p = 0.001) in our data (Table 1). In summary, we demonstrated that in a Han Chinese population cohort, the TM6SF2 167K allele has a similar allele frequency as reported in Caucasian populations ( 7%) [1–3] but higher than that in African-Americans (3.4%) [1], HispanicAmericans (4.7%) [1], and Argentinians (5.5%) [9]. Our data suggests that this variant significantly contributes to increased NAFLD risk in Chinese population, independent of the PNPLA3 rs738409 and NCAN rs2228603 polymorphisms. This observation further highlights the independent and potentially causal role of rs58542926 in the disease biology of NAFLD. However, further investigation is needed in East Asian populations to test whether it is also involved in NAFLD disease progression and severity, especially using biopsy-characterized samples.

Genome-wide search for loss of heterozygosity in Chinese patients with sporadic colorectal cancer

In an attempt to integrally investigate the loss of tumor suppressor genes and search for putative suppressor loci associated with tumor occurrence and progression, we conducted a genome-wide loss of heterozygosity (LOH) study of 83 tumor samples obtained from Chinese patients with sporadic colorectal cancer. We employed 400 fluorescence-labeled microsatellite marker primers to amplify the corresponding loci of the genomic DNA and then electrophoresed the polymerase chain reaction products and analyzed the fluorescent signals. The LOH frequencies were high (>35%) but were not associated with the tumor stage and progression in 20 loci, including the regions where TP53, E-cadherin, deleted in colorectal carcinoma (DCC), phosphatase and tensin homolog deleted on chromosome 10 (PTEN), mothers against decapentaplegic, Drosophila, homolog of 2 (MADH2) and mothers against decapentaplegic, Drosophila, homolog of 4 (MADH4) reside. Loss of other loci, including two narrow regions on chromosome 2, was found to relate to the tumor stage, suggesting that this genomic instability may contribute to tumor progression.

Additive Effects of the Risk Alleles of PNPLA3 and TM6SF2 on Non-alcoholic Fatty Liver Disease (NAFLD) in a Chinese Population.

Recent genome-wide association studies have identified that variants in or near PNPLA3, NCAN, GCKR, LYPLAL1, and TM6SF2 are significantly associated with non-alcoholic fatty liver disease (NAFLD) in multiple ethnic groups. Studies on their impact on NAFLD in Han Chinese are still limited. In this study, we examined the relevance of these variants to NAFLD in a community-based Han Chinese population and further explored their potential joint effect on NAFLD. Six single nucleotide polymorphisms (SNPs) (PNPLA3 rs738409, rs2294918, NCAN rs2228603, GCKR rs780094, LYPLAL1 rs12137855, and TM6SF2 rs58542926) previously identified in genome-wide analyses, to be associated with NAFLD were genotyped in 384 NAFLD patients and 384 age- and gender-matched healthy controls. We found two out of the six polymorphisms, PNPLA3 rs738409 (OR = 1.52, 95%CI: 1.19–1.96; P = 0.00087) and TM6SF2 rs58542926 (OR = 2.11, 95%CI: 1.34–3.39; P = 0.0016) are independently associated with NAFLD after adjustment for the effects of age, gender, and BMI. Our analysis further demonstrated the strong additive effects of the risk alleles of PNPLA3 and TM6SF2 with an overall significance between the number of risk alleles and NAFLD (OR = 1.64, 95%CI: 1.34–2.01; P = 1.4 × 10-6). The OR for NAFLD increased in an additive manner, with an average increase in OR of 1.52 per additional risk allele. Our results confirmed that the PNPLA3 and TM6SF2 variants were the most significant risk alleles for NAFLD in Chinese population. Therefore, genotyping these two genetic risk factors may help identify individuals with the highest risk of NAFLD.

Resolvin D1 protects against inflammation in experimental acute pancreatitis and associated lung injury

Acute pancreatitis is an inflammatory condition that may lead to multisystemic organ failure with considerable mortality. Recently, resolvin D1 (RvD1) as an endogenous anti-inflammatory lipid mediator has been confirmed to protect against many inflammatory diseases. This study was designed to investigate the effects of RvD1 in acute pancreatitis and associated lung injury. Acute pancreatitis varying from mild to severe was induced by cerulein or cerulein combined with LPS, respectively. Mice were pretreated with RvD1 at a dose of 300 ng/mouse 30 min before the first injection of cerulein. Severity of AP was assessed by biochemical markers and histology. Serum cytokines and myeloperoxidase (MPO) levels in pancreas and lung were determined for assessing the extent of inflammatory response. NF-κB activation was determined by Western blotting. The injection of cerulein or cerulein combined with LPS resulted in local injury in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the cerulein and LPS group. Pretreated RvD1 significantly reduced the degree of amylase, lipase, TNF-α, and IL-6 serum levels; the MPO activities in the pancreas and the lungs; the pancreatic NF-κB activation; and the severity of pancreatic injury and associated lung injury, especially in the severe acute pancreatitis model. These results suggest that RvD1 is capable of improving injury of pancreas and lung and exerting anti-inflammatory effects through the inhibition of NF-κB activation in experimental acute pancreatitis, with more notable protective effect in severe acute pancreatitis. These findings indicate that RvD1 may constitute a novel therapeutic strategy in the management of severe acute pancreatitis.

Efficacy of Surgery and Adjuvant Therapy in Older Patients With Colorectal Cancer: A STROBE-compliant article

AbstractThe present study aimed to assess the efficacy of surgery and adjuvant therapy in older patients (age ≥70 years) with colorectal cancer (CRC). Older CRC patients are under-represented in available clinical trials, and therefore their outcomes after receiving surgery and adjuvant therapy are unclear. From two prospective Swedish databases, we assessed a cohort of 1021 patients who underwent curative surgery for stage I, II, or III primary CRC, with or without adjuvant chemotherapy/radiotherapy. Of the patients with colon cancer (nu200a=u200a467), 182 (39%) were aged <70 years, 162 (35%) aged 70 to 80 years, and 123 (26%) were aged ≥80 years. Of rectal cancer patients (nu200a=u200a554), 264 (48%) were aged <70 years, 234 (42%) aged 70 to 80 years, and 56 (10%) aged ≥80 years. Older patients with either colon or rectal cancer had higher comorbidity than did younger patients. Older patients with colon cancer had equivalent postoperative morbidity and 30-day mortality to younger patients. Rectal cancer patients aged ≥80 years had a higher 30-day mortality than younger patients (odds ratio [OR], 2.37; 95% confidence interval [CI], 1.6–4.55; Pu200a=u200a0.03). For either colon or rectal cancer, adjuvant chemotherapy compromised the 5-year overall survival (OS) of older patients with stage II disease and had no effect on those with stage III disease. Receiving adjuvant chemotherapy was a poor factor of OS for older patients with either colon (HR 1.88, 95% CI: 1.20–4.35, Pu200a=u200a0.03) or rectal cancer (HR 1.72, 95% CI: 1.05–2.26, Pu200a=u200a0.004). Preoperative short-course radiotherapy improved both OS and local control for older patients with stage III rectal cancer and had no effect on those with stage II disease. Radiotherapy was a favorable factor for the OS of the older patients with rectal cancer (HR 0.42, 95% CI: 0.21–3.57, Pu200a=u200a0.01). In conclusion, Older CRC patients had equal safety of surgery as younger patients, except rectal cancer patients aged ≥80 years that had a higher mortality. Adjuvant 5FU-based chemotherapy did not benefit older CRC patient, while neoadjuvant radiotherapy improved the prognosis of older patients with stage III rectal cancer.

Effects of Tocilizumab on Experimental Severe Acute Pancreatitis and Associated Acute Lung Injury.

Objective:To examine the therapeutic effects of tocilizumab, an antibody against interleukin-6 receptor, on experimental severe acute pancreatitis and associated acute lung injury. The optimal dose of tocilizumab and the activation of interleukin-6 inflammatory signaling were also investigated. Design:Randomized experiment. Setting:Research laboratory at a university hospital. Subject:Experimental severe acute pancreatitis in rats. Interventions:Severe acute pancreatitis was induced by retrograde injection of sodium taurocholate (50u2009mg/kg) into the biliopancreatic duct. In dose-study, rats were administered with different doses of tocilizumab (1, 2, 4, 8, and 16u2009mg/kg) through the tail vein after severe acute pancreatitis induction. In safety-study, rats without severe acute pancreatitis induction were treated with high doses of tocilizumab (8, 16, 32, and 64u2009mg/kg). Serum and tissue samples of rats in time-study were collected for biomolecular and histologic evaluations at different time points (2, 6, 12, 18, and 24u2009hr). Measurements and Main Results:1) Under the administration of tocilizumab, histopathological scores of pancreas and lung were decreased, and severity parameters related to severe acute pancreatitis and associated lung injury, including serum amylase, C-reactive protein, lung surfactant protein level, and myeloperoxidase activity, were all significant alleviated in rat models. 2) Dose-study demonstrated that 2u2009mg/kg tocilizumab was the optimal treatment dose. 3) Basing on multi-organ pathologic evaluation, physiological and biochemical data, no adverse effect and toxicity of tocilizumab were observed in safety-study. 4) Pancreatic nuclear factor-&kgr;B and signal transducer and activator of transcription 3 were deactivated, and the serum chemokine (C-X-C motif) ligand 1 was down-regulated after tocilizumab administration. Conclusions:Our study demonstrated tocilizumab, as a marketed drug commonly used for immune-mediated diseases, was safe and effective for the treatment of experimental severe acute pancreatitis and associated acute lung injury. Our findings provide experimental evidences for potential clinical application of tocilizumab in severe acute pancreatitis and associated complications.

CD133 + CD54 + CD44 + circulating tumor cells as a biomarker of treatment selection and liver metastasis in patients with colorectal cancer

Introduction Liver is the most common site of distant metastasis in colorectal cancer (CRC). Early diagnosis and appropriate treatment selection decides overall prognosis of patients. However, current diagnostic measures were basically imaging but not functional. Circulating tumor cells (CTCs) known as hold the key to understand the biology of metastatic mechanism provide a novel and auxiliary diagnostic strategy for CRC with liver metastasis (CRC-LM). Results The expression of CD133+ and CD133+CD54+CD44+ cellular subpopulations were higher in the peripheral blood of CRC-LM patients when compared with those without metastasis (P<0.001). Multivariate analysis proved the association between the expression of CD133+CD44+CD54+ cellular subpopulation and the existence of CRC-LM (P<0.001). The combination of abdominal CT/MRI, CEA and the CD133+CD44+CD54+ cellular subpopulation showed increased detection and discrimination rate for liver metastasis, with a sensitivity of 88.2% and a specificity of 92.4%. Meanwhile, it also show accurate predictive value for liver metastasis (OR=2.898, 95% C.I.1.374–6.110). Materials and Method Flow cytometry and multivariate analysis was performed to detect the expression of cancer initiating cells the correlation between cellular subpopulations and liver metastasis in patients with CRC. The receiver operating characteristic curves combined with the area under the curve were generated to compare the predictive ability of the cellular subpopulation for liver metastasis with current CT and MRI images. Conclusions The identification, expression and application of CTC subpopulations will provide an ideal cellular predictive marker for CRC liver metastasis and a potential marker for further investigation.