Hydraulic properties and drought response of a tropical bamboo (Cephalostachyum pergracile).

Bamboo plants are an essential component of tropical ecosystems, yet their vulnerability to climate extremes, such as drought, is poorly understood due to limited knowledge of their hydraulic properties. Cephalostachyum pergracile, a commonly used tropical bamboo species, exhibited a substantially higher mortality rate than other co-occurring bamboos during a severe drought event in 2019, but the underlying mechanisms remain unclear. This study investigated the leaf and stem hydraulic traits related to drought responses, including leaf-stem embolism resistance (P50leaf; P50stem) estimated using optical and X-ray microtomography methods, leaf pressure-volume and water-releasing curves. Additionally, we investigated the seasonal water potentials, native embolism level (PLC) and xylem water source using stable isotope. We found that C. pergracile exhibited strong resistance to embolism, showing low P50leaf, P50stem, and turgor loss point, despite its rapid leaf water loss. Interestingly, its leaves displayed greater resistance to embolism than its stem, suggesting a lack of effective hydraulic vulnerability segmentation (HVS) to protect the stem from excessive xylem tension. During the dry season, approximately 49% of the water was absorbed from the upper 20-cm-deep soil layer. Consequently, significant diurnal variation in leaf water potentials and an increase in midday PLC from 5.87 ± 2.33% in the wet season to 12.87 ± 4.09% in the dry season were observed. In summary, this study demonstrated that the rapid leaf water loss, high reliance on surface water, and a lack of effective HVS in C. pergracile accelerated water depletion and increased xylem embolism even in the typical dry season, which may explain its high mortality rate during extreme drought events in 2019.

A Decade of Scientific and Technological Innovation at Chinese Academy of Medical Sciences & Peking Union Medical College: Retrospect and Prospect.

Focusing on the reform initiatives of Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC) in medical scientific and technological innovation from perspectives of deepening the reform and optimizing the ecosystem of science and technology innovation, this article summarizes the highlights of CAMS & PUMC's efforts in safeguarding people's health and promoting the Healthy China 2030 strategy through scientific and technological innovation in the fields including basic research, disease prevention and treatment, and medical technology in the past ten years. These achievements embody the endeavors and responsibility of CAMS & PUMC in realizing self-reliance and self-improvement of Chinese medical science and technology and highlight its contributions to the development of medical science and technology of China.

Factors Related to Activation in Chinese Patients With Chronic Obstructive Pulmonary Disease: A Cross-Sectional Survey Study.

BACKGROUND: Improving patient activation can lead to better health outcomes among patients with chronic obstructive pulmonary disease (COPD). However, no studies have focused on the issue of activation in patients with COPD in China. PURPOSE: This study was designed to explore the status of activation in patients with COPD in China and explicate the significant influencing factors. METHODS: One hundred seventy patients with COPD were recruited using a convenience sampling method from eight tertiary and secondary hospitals in Nanjing, China. Sociodemographic, clinical, and patient-reported factor data were collected. Univariate analysis and multivariate linear regression were performed. RESULTS: Only 10.6% of the patients were identified as activated for self-management. Multivariate linear regression analysis revealed four explanatory elements as significantly associated with patient activation, including social support (ß = .463, p < .001), free medical insurance (ß = .173, p = .007), smoking status (ß = -.195, p = .002), and health status (ß = -.139, p = .04). CONCLUSIONS/IMPLICATIONS FOR PRACTICE: The findings of this study indicate that a minority of patients with COPD are activated for self-management in China. Having a higher level of patient activation was associated with having better social support, having free medical insurance, being a nonsmoker, and having a better health status. Creating a supportive environment, promoting smoking cessation, and improving medical security and health status may be considered as potential strategies to activate patients into better self-management.

The effects of case management for breast cancer patients: A protocol for systematic review and meta-analysis.

BACKGROUND: Female breast cancer is the most common cancer nowadays, and its treatment has a significant impact on patients both physically and psychologically. Many randomized trials have proved that case management (CM) can effectively care for patients. However, there is a lack of systematic scientific evaluation, so this systematic evaluation aims to explore the impact of CM on breast cancer patients. METHODS: PubMed, Embase, Cochrane Library, Scopus, CINAHL were searched. Chinese repositories included China National Knowledge, Infrastructure Database (CNKI), Wan fang Database, China Biology Medicine Database. We will also search unpublished literature at ClinicalTrials.gov. Randomized controlled trials were collected from them. The literature will be screened according to inclusion and exclusion criteria, and 2 researchers will extract the literature independently. The primary outcome indicator for this study will be patient satisfaction. Statistics were performed using RevMan 5.4 software. The quality of each outcome will be evaluated using the Grading of Recommendations Assessment, Development, and Evaluation. RESULTS: This study will provide the most recent evidence for evaluating the impact of CM on breast cancer patients. CONCLUSION: To evaluate the impact of CM on patients with breast cancer. REGISTRATION NUMBER: DOI:10.17605/OSF.IO/ZJKHX.

Response of four evergreen savanna shrubs to an incidence of extreme drought: high embolism resistance, branch shedding and maintenance of nonstructural carbohydrates.

Extreme drought events are becoming frequent globally, resulting in widespread plant mortality and forest dieback. Although savanna vegetation cover ~20% of the earth's land area, their responses to extreme drought have been less studied than that of forests. Herein, we quantified branch dieback, individual mortality and the associated physiological responses of four evergreen shrubs (Tarenna depauperate Hutch., Maytenus esquirolii (H. Lév.) C.Y. Cheng, Murraya exotica L., Jasminum nudiflorum Lindl.) in a savanna ecosystem in Southwest China to an incidence of extreme drought during 2019 and 2020. We found that 80-100% of the individuals of these species exhibited branch dieback, whereas individual mortality was only found in T. depauperate (4.5%). All species showed high resistance to stem embolism (P50, water potential at 50% loss of hydraulic conductivity ranged from -5.62 to -8.6 MPa), whereas the stem minimum water potentials reached -7.6 to ca -10.0 MPa during the drought. The low water potential caused high native embolism levels (percentage loss of hydraulic conductivity (PLC) 23-65%) in terminal branches, and the remaining stems maintained 15-35% PLC at the end of the drought. Large within-individual variations in stem vulnerability to embolism were detected, and shedding of vulnerable branches could be a mechanism for shrubs to reduce water and carbon consumption. Overall, the content of total nonstructural carbohydrates (NSC) and their components in the stem were generally comparable to or higher than those in the rainy season in three of the four species. Because the leaves were turgor-less for most time during the drought, high NSC levels during the drought could be due to recycling of NSC from dead branches or translocation from roots. Our results suggest high tolerance of savanna shrub species to extreme drought, which could be facilitated by high embolism resistance in some stems and shedding of vulnerable branches to maintain individual water and carbon balance.

Deep Sequencing Discovery and Profiling of Known and Novel miRNAs Produced in Response to DNA Damage in Rice.

Under extreme environmental conditions such as ultraviolet and ionizing radiation, plants may suffer DNA damage. If these damages are not repaired accurately and rapidly, they may lead to chromosomal abnormalities or even cell death. Therefore, organisms have evolved various DNA repair mechanisms to cope with DNA damage which include gene transcription and post-translational regulation. MicroRNA (miRNA) is a type of non-coding single-stranded RNA molecule encoded by endogenous genes. They can promote DNA damage repair by regulating target gene transcription. Here, roots from seedlings of the japonica rice cultivar 'Yandao 8' that were treated with bleomycin were collected for transcriptome-level sequencing, using non-treated roots as controls. A total of 14,716,232 and 17,369,981 reads mapping to miRNAs were identified in bleomycin-treated and control groups, respectively, including 513 known and 72 novel miRNAs. Compared with the control group, 150 miRNAs showed differential expression levels. Target predictions of these differentially expressed miRNAs yielded 8731 potential gene targets. KEGG annotation and a gene ontology analysis indicated that the highest-ranked target genes were classified into metabolic processes, RNA degradation, DNA repair, and so on. Notably, the DNA repair process was significantly enriched in both analyses. Among these differentially expressed miRNAs, 58 miRNAs and 41 corresponding potential target genes were predicted to be related to DNA repair. RT-qPCR results confirmed that the expression patterns of 20 selected miRNAs were similar to those from the sequencing results, whereas four miRNAs gave opposite results. The opposing expression patterns of several miRNAs with regards to their target genes relating to the DNA repair process were also validated by RT-qPCR. These findings provide valuable information for further functional studies of miRNA involvement in DNA damage repair in rice.

Transcriptome analysis of ovary culture-induced embryogenesis in cucumber (Cucumis sativus L.).

BACKGROUND: Ovary culture is a useful technique used to generate double haploid (DH) cucumber (Cucumis sativus L.) plants. However, cucumber ovary culture have a low rate of embryo induction and plant regeneration. Moreover, the cucumber embryogenesis mechanism remains unclear. In this study, we explored the molecular basis of cucumber embryogenesis in order to establish a foundation for a more efficient ovary culture method. Using transcriptome sequencing, we also investigated the differential expression of genes during the embryogenesis process. METHODS: Cytological and morphological observations have divided cucumber ovary culture into three stages: early embryo development (T0), embryo morphogenesis (T1, T2, T3 and T4), and shoot formation (T5). We selected six key time points for transcriptome sequencing and analysis: T0 (the ovules were cultured for 0 d), T1 (the ovules were cultured for 2 d), T2 (the embryos were cultured for 10 d), T3 (the embryos were cultured for 20 d), T4 (the embryos were cultured for 30 d), and T5 (the shoots after 60 d culture). RESULTS: We used cytology and morphology to observe the characteristics of the cucumber's developmental transformation during embryogenesis and plant regeneration. The differentially expressed genes(DEGs) at developmental transition points were analyzed using transcriptome sequencing. In the early embryogenesis stage, the cells expanded, which was the signal for gametophytes to switch to the sporophyte development pathway. RNA-seq revealed that when compared to the fresh unpollinated ovaries, there were 3,468 up-regulated genes in the embryos, including hormone signal transduction genes, hormone response genes, and stress-induced genes. The reported embryogenesis-related genes BBM, HSP90 and AGL were also actively expressed during this stage. In the embryo morphogenesis stage (from cell division to cotyledon-embryo formation), 480 genes that functioned in protein complex binding, microtubule binding, tetrapyrrole binding, tubulin binding and other microtubule activities were continuously up-regulated during the T1, T2, T3 and T4 time points. This indicated that the cytoskeleton structure was continuously being built and maintained by the action of microtubule-binding proteins and enzyme modification. In the shoot formation stage, 1,383 genes were up-regulated that were mainly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, phenylalanine metabolism, and starch and sucrose metabolism. These up-regualted genes included six transcription factors that contained a B3 domain, nine genes in the AP2/ERF family, and two genes encoding WUS homologous domain proteins. CONCLUSIONS: Evaluation of molecular gynogenesis events may contribute to a better understanding of the molecular mechanism of cucumber ovarian culture.

Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits?

Vulnerability curves (VCs) describe the loss of hydraulic conductance against increasing xylem tension, providing valuable insights about the response of plant water transport to water stress. Techniques to construct VCs have been developed and modified continuously, but controversies continue. We compared VCs constructed using the bench-top dehydration (BD), air-injection-flow (AI), pneumatic-air-discharge (PAD), optical (OP) and X-ray-computed microtomography (MicroCT) methods for tropical trees and lianas with contrasting vessel lengths. The PAD method generated highly vulnerable VCs, the AI method intermediate VCs, whereas the BD, OP and MicroCT methods produced comparable and more resistant VCs. Vessel-length and diameter accounted for the overestimation ratio of vulnerability estimated using the AI but not the PAD method. Compared with directly measured midday embolism levels, the PAD and AI methods substantially overestimated embolism, whereas the BD, MicroCT and OP methods provided more reasonable estimations. Cut-open vessels, uncertainties in maximum air volume estimations, sample-length effects, tissue cracks and shrinkage together may impede the reliability of the PAD method. In conclusion, we validate the BD, OP and MicroCT methods for tropical plants, whereas the PAD and AI need further mechanistic testing. Therefore, applications of VCs in estimating plant responses to drought need to be cautious.

Nuclear Hormone Receptors and Their Ligands: Metabolites in Control of Transcription.

Nuclear hormone receptors are a family of transcription factors regulated by small molecules derived from the endogenous metabolism or diet. There are forty-eight nuclear hormone receptors in the human genome, twenty of which are still orphans. In this review, we make a brief historical journey from the first observations by Berthold in 1849 to the era of orphan receptors that began with the sequencing of the Caenorhabditis elegans genome in 1998. We discuss the evolution of nuclear hormone receptors and the putative ancestral ligands as well as how the ligand universe has expanded over time. This leads us to define four classes of metabolites-fatty acids, terpenoids, porphyrins and amino acid derivatives-that generate all known ligands for nuclear hormone receptors. We conclude by discussing the ongoing efforts to identify new classes of ligands for orphan receptors.

Single-molecule real-time sequencing of the full-length transcriptome of loquat under low-temperature stress.

In this study, third-generation full-length (FL) transcriptome sequencing was performed of loquat using single-molecule real-time(SMRT) sequencing from the pooled cDNA of embryos of young loquat fruit under different low temperatures (three biological replicates for treatments of 1°C, -1°C, and -3°C, for 12 h or 24 h) and the control group(three biological replicates for treatments of room temperature), Illumina sequencing was used to correct FL transcriptome sequences. A total of 3 PacBio Iso-Seq libraries (1-2 kb, 2-3 kb and 3-6 kb) and 21 Illumina transcriptome libraries were constructed, a total of 13.41 Gb of clean reads were generated, which included 215,636 reads of insert (ROIs) and 121,654 FL, non-chimaric (FLNC) reads. Transcript clustering analysis of the FLNC reads revealed 76,586 consensus isoforms, and a total of 12,520 high-quality transcript sequences corrected with non-FL sequences were used for subsequent analysis. After the redundant reads were removed, 38,435 transcripts were obtained. A total of 27,905 coding DNA sequences (CDSs) were identified, and 407 long non-coding RNAs (lncRNAs) were ultimately predicted. Additionally, 24,832 simple sequence repeats (SSRs) were identified, and a total of 1,295 alternative splicing (AS) events were predicted. Furthermore, 37,993 transcripts were annotated in eight functional databases. This is the first study to perform SMRT sequencing of the FL transcriptome of loquat. The obtained transcriptomic data are conducive for further exploration of the mechanism of loquat freezing injury and thus serve as an important theoretical basis for generating new loquat material and for identifying new ways to improve loquat cold resistance.

Pathological analysis of the superior mesenteric artery boundary in preoperative computed tomography of resectable pancreatic head adenocarcinoma.

The aim of the present study was to evaluate the biological and prognostic implications of the superior mesenteric artery (SMA) boundary on preoperative abdominal contrast-enhanced computed tomography (CE-CT) for resectable adenocarcinoma of the pancreatic head. A total of 121 patients treated over a 6-year period at Peking University Third Hospital (Beijing, China) were included in the present study. The pattern of the SMA boundary was investigated on preoperative CE-CT and detailed pathological analysis of the extrapancreatic plexus [the pancreatic head plexus II (PLX-II) located on the right edge of the SMA] was performed. The results revealed that the radiological SMA boundary was associated with the grade of parasympathetic neurogenesis (P=0.014) in PLX-II, and was predictive of postoperative disease-free survival (P=0.014) and liver metastasis (P=0.013). Therefore, it was proposed that extrapancreatic parasympathetic neurogenesis may account for the different patterns of the SMA boundary on preoperative abdominal CE-CT, and affect the prognosis, particularly for liver metastasis in resectable pancreatic head adenocarcinoma.

Clinicopathological features and prognosis factors for survival in elderly patients with pancreatic neuroendocrine tumor: A STROBE-compliant article.

To investigate the features and prognosis of the elderly patients with pancreatic neuroendocrine tumor (pNET).The patients diagnosed with pNETs between 2004 and 2014 were identified from the Surveillance Epidemiology and End Results database. The ethical approval was waived because the present study was analysis of the data from Surveillance Epidemiology and End Results database.A total of 4608 patients with "one primary only" histologically pNETs were confirmed and 653 were older than 75 years. Cancer-specific survival (CSS) and overall survival (OS) were examined. The elderly patients (≥75 years) have disadvantage in CSS and OS compared with younger cohort. Multivariate logistic regression revealed that the elderly patients have increased poorly differentiated composition, and decreased proportion of Black patients, receipt of surgery, married status, and number of removed lymph node. Multivariate Cox regression analysis demonstrated worse differentiation. Patients of T3-4 and M1 stage were associated with poor CSS, while patients of being female, tumor locating at pancreatic body/tail, receipt of surgery, and being married were associated with better CSS in the elderly patients. Meanwhile, patients with higher histological grade and M1 stage have poor OS, while patients with the characteristics of female, being married, tumor location at pancreatic body/tail and tumor surgery have better OS. Distant metastatic elderly patients underwent primary site surgery had better CSS and OS than the patients without surgery.The elderly patients have increased possibility of poorly differentiated tumor, and decreased proportion of Black patients, surgery of primary site, number of removed lymph node and married status. Worse differentiation and tumor metastasis were independent risk factors for both CSS and OS, while primary tumor located in body/tail of pancreas, female patients, surgery of tumor primary site, and being married were protective factors.

Extrapancreatic Neuropathy Correlates with Early Liver Metastasis in Pancreatic Head Adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma has a devastatingly poor prognosis, and most prognostic factors reflected the tumor stage more than the tumors' biology. The peripheral nerve plexus is densely distributed in the tumor micro-environment, and there are interactions between tumor cells and these nerves. Perineural invasion is an important risk factor for tumor recurrence and metastasis in pancreatic head adenocarcinoma, but the concrete types of extrapancreatic neuropathy and its role in predicting prognosis are still not clear. OBJECTIVE: To clarify the role of extrapancreatic neuropathy in the early postoperative liver metastasis and tumor-related mortality in pancreatic head adenocarcinoma and to study the mechanism of tumor recurrence and liver metastasis in pancreatic head adenocarcinoma. METHODS: We reported a retrospective study of 60 patients with resectable pancreatic head adenocarcinoma, all of whom accepted radical pancreaticoduodenectomy. Plexus pancreaticus capitalis II (PLX-II) was the representation of extrapancreatic plexus in our study, and all of these plexus had immunohistochemical staining. We defined the postoperative tumor recurrence and tumor-related mortality within 6 months as the early prognostic indicators and analyzed the pathological alterations in PLX-II among different prognosis groups. RESULTS: There were 18 patients suffering early postoperative liver metastasis; these two groups differed significantly in the average number of nerve trunks (P<0.001), the proportion of neuritis (P=0.003), the content of sympathetic nerve fibers (P=0.004) and parasympathetic nerve fibers (P<0.001) per unit area of PLX-II. There were 15 patients suffering early postoperative mortality, and there were significant differences between these two groups in the average number of nerve trunks (P<0.001), the proportion of neuritis (P=0.009), the content of sympathetic nerve fibers (P=0.023) and parasympathetic nerve fibers (P<0.001) per unit area of PLX-II. CONCLUSION: The patterns of extrapancreatic neuropathy could reflect the biological behavior of resectable pancreatic head adenocarcinoma, and the pathological features of PLX-II were closely related to early liver metastasis and mortality.

Real-time Iontophoresis with Tetramethylammonium to Quantify Volume Fraction and Tortuosity of Brain Extracellular Space.

This review describes the basic concepts and protocol to perform the real-time iontophoresis (RTI) method, the gold-standard to explore and quantify the extracellular space (ECS) of the living brain. The ECS surrounds all brain cells and contains both interstitial fluid and extracellular matrix. The transport of many substances required for brain activity, including neurotransmitters, hormones, and nutrients, occurs by diffusion through the ECS. Changes in the volume and geometry of this space occur during normal brain processes, like sleep, and pathological conditions, like ischemia. However, the structure and regulation of brain ECS, particularly in diseased states, remains largely unexplored. The RTI method measures two physical parameters of living brain: volume fraction and tortuosity. Volume fraction is the proportion of tissue volume occupied by ECS. Tortuosity is a measure of the relative hindrance a substance encounters when diffusing through a brain region as compared to a medium with no obstructions. In RTI, an inert molecule is pulsed from a source microelectrode into the brain ECS. As molecules diffuse away from this source, the changing concentration of the ion is measured over time using an ion-selective microelectrode positioned roughly 100 µm away. From the resulting diffusion curve, both volume fraction and tortuosity can be calculated. This technique has been used in brain slices from multiple species (including humans) and in vivo to study acute and chronic changes to ECS. Unlike other methods, RTI can be used to examine both reversible and irreversible changes to the brain ECS in real time.

Effects of different source additives and wilt conditions on the pH value, aerobic stability, and carbohydrate and protein fractions of alfalfa silage.

To improve the silage quality and reduce the silage additive cost, the present experiment was designed to evaluate the potential of applying the fermented juice of epiphytic lactic acid bacteria (FJLB) as an additive in alfalfa silage. The effects of FJLB on the fermentation quality, carbohydrate and protein fractions, and aerobic stability of alfalfa silage wilted under five different conditions were investigated and compared with commercial lactic acid bacteria (CLAB) and the control. The FJLB application decreased the pH value, the volatile fatty acids and non-protein nitrogen content, and the loss of sugar by 9.9%, 22.9%, 19.6% and 9.6%, respectively; it increased the lactic acid concentration by 29.5% and the aerobic stability by 17 h in comparison to the control. The FJLB application also decreased the pH value (4.44 vs. 4.66) and volatile fatty acid content (38.32 vs. 44.82) and increased the lactic acid concentration (68.99 vs. 63.29) in comparison to the CLAB-treated silage. However, the FJLB treatment had lower aerobic stability (254 h vs. 274 h) than the CLAB treatment. The FJLB application improved silage quality in comparison to the control; in addition, its effect as a fermentation stimulant may be comparable to or even better than CLAB.

Hepatitis B virus is associated with the clinical features and survival rate of patients with intrahepatic cholangiocarcinoma.

BACKGROUND AND OBJECTIVE: The pathogenesis and development of intrahepatic cholangiocarcinoma (ICC) may be triggered by hepatitis B virus (HBV). We conducted this retrospective study to explore the potential association between HBV infection and the clinical features and survival rate of patients with ICC. METHODS: Patients with ICC who had undergone a curative resection were enrolled and divided into three groups according to the seropositivity of the hepatitis B surface antigen (HBsAg) and the hepatitis B core antibody (anti-HBc). The groups were as follows: group I, HBsAg (+)/anti-HBc (+); group II, HBsAg (-)/anti-HBc (+); group III HBsAg (-)/anti-HBc (-). The symptoms, pathologic findings, and outcome information of all patients were retrospectively reviewed. The patient sera were isolated to detect anti-HCV, HBsAg, and anti-HBc. Surgical specimens were assessed by hematoxylin and eosin (HE) staining. The expression of cytokeratin 7 was evaluated by immunohistochemistry. Finally, the 1-, 3-, and 5-year cumulative survival rates were analyzed. RESULTS: Ninety-seven patients with ICC were enrolled in group I (n=26); group II, (n=50), and group III (n=21). A total of 26.8% (26/97) patients with ICC were positive for HBsAg. Patients with HBV-associated ICC tended to be younger (P=0.018), have lower CA19-9 levels (P=0.000), a higher alpha fetal protein (AFP) level (P=0.012) and prothrombin time (P=0.030), a higher risk of hepatic cirrhosis (P=0.001), and poor differentiation (P=0.028). The 1-, 3-, and 5-year cumulative survival rates for patients within the three groups were as follows: 27.3%, 0%, and 0% for group I, respectively; 62.5%, 30.0%, and 0% for group II, respectively; and 87.5%, 66.7%, and 50.0% for group III, respectively. The results were significantly different in an overall comparison (P=0.000). CONCLUSION: Patients with HBV-associated ICC showed different clinicopathological features and lower survival rates compared to patients with ICC without HBV infection.

Prognostic significance of K-ras mutations in pancreatic cancer: a meta-analysis.

BACKGROUND: K-ras gene mutations are common in patients with pancreatic cancer (PC); however, their prognostic value for PC remains inconclusive. This meta-analysis was performed to quantitatively evaluate the association between K-ras mutations and survival in patients with pancreatic cancer. METHODS: We performed a comprehensive search of electronic sources including MEDLINE (via PubMed), Web of Science, and the Cochrane Library. The search covered a publication period from inception to November 2015. RESULTS: Seventeen studies with a total of 2249 patients with pancreatic cancer were included in the tissue detection of this study. The meta-analysis indicated a significant association between mutant K-ras genes and overall survival (OS) (HR = 1.51, 95% CI 1.32-1.72, P < 0.001). Moreover, further subgroup analyses by ethnicity, publication year, therapy method, cancer resectability, and gene detection method all revealed that pancreatic cancer patients with the K-ras mutation had significantly poorer OS (P < 0.05). And results from four studies with 225 patients focused on plasma K-ras mutations enhanced such association (HR = 2.23, 95% CI 1.69-2.95, P < 0.001). CONCLUSIONS: As a prediction of poor prognosis, the detection of K-ras mutations may be a useful prognostic factor for pancreatic cancer patients.

Myeloid-derived suppressor cells mediate immune suppression in spinal cord injury.

Spinal cord injury (SCI) is characterized by the loss of motor and sensory functions in areas below the level of the lesion and numerous accompanying deficits. Previous studies have suggested that myeloid-derived suppressor cell (MDSC)-induced immune depression may play a pivotal role in the course of SCI. However, the concrete mechanism of these changes regarding immune suppression remains unknown. Here, we created an SCI mouse model to gain further evidence regarding the relationship between MDSCs following SCI and T lymphocyte suppression. We showed that in the SCI mouse model, the expanding MDSCs have the capacity to suppress T cell proliferation, and this suppression could be reversed by blocking the arginase.

Simultaneous quantification of alternatively spliced transcripts in a single droplet digital PCR reaction.

Human telomerase reverse transcriptase (hTERT) is an essential component required for telomerase activity and telomere maintenance. Several alternatively spliced forms of hTERT mRNA have been reported in human primary and tumor cells. Currently, however, there is no sensitive and accurate method for the simultaneous quantification of multiple alternatively spliced RNA transcripts, such as in the case of hTERT. Here we show droplet digital PCR (ddPCR) provides sensitive, simultaneous digital quantification in a single reaction of two alternatively spliced single deletion hTERT transcripts (α-/ß+ and α+/ß-) as well as the opportunity to manually quantify non-deletion (α+/ß+) and double deletion (α-/ß-) transcripts. Our ddPCR method enables direct comparison among four alternatively spliced mRNAs without the need for internal standards or multiple primer pairs specific for each variant as real-time PCR (qPCR) requires, thus eliminating potential variation due to differences in PCR amplification efficiency.

Telomerase enzymatic component hTERT shortens long telomeres in human cells.

Telomere lengths are tightly regulated within a narrow range in normal human cells. Previous studies have extensively focused on how short telomeres are extended and have demonstrated that telomerase plays a central role in elongating short telomeres. However, much about the molecular mechanisms of regulating excessively long telomeres is unknown. In this report, we demonstrated that the telomerase enzymatic component, hTERT, plays a dual role in the regulation of telomere length. It shortens excessively long telomeres and elongates short telomeres simultaneously in one cell, maintaining the optimal telomere length at each chromosomal end for efficient protection. This novel hTERT-mediated telomere-shortening mechanism not only exists in cancer cells, but also in primary human cells. The hTERT-mediated telomere shortening requires hTERT's enzymatic activity, but the telomerase RNA component, hTR, is not involved in that process. We found that expression of hTERT increases telomeric circular DNA formation, suggesting that telomere homologous recombination is involved in the telomere-shortening process. We further demonstrated that shelterin protein TPP1 interacts with hTERT and recruits hTERT onto the telomeres, suggesting that TPP1 might be involved in regulation of telomere shortening. This study reveals a novel function of hTERT in telomere length regulation and adds a new element to the current molecular model of telomere length maintenance.