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2.
Artigo em Inglês | MEDLINE | ID: mdl-33811460

RESUMO

BACKGROUND: Although we previously proposed a nomogram to predict malignancy in intraductal papillary mucinous neoplasms (IPMN) and validated it in an external cohort, its application is challenging without data on tumor markers. Moreover, existing nomograms have not been compared. This study aimed to develop a nomogram based on radiologic findings and to compare its performance with previously proposed American and Korean/Japanese nomograms. METHODS: We recruited 3708 patients who underwent surgical resection at 31 tertiary institutions in eight countries, and patients with main pancreatic duct > 10 mm were excluded. To construct the nomogram, 2606 patients were randomly allocated 1:1 into training and internal validation sets, and area under the receiver operating characteristics curve (AUC) was calculated using 10-fold cross validation by exhaustive search. This nomogram was then validated and compared to the American and Korean/Japanese nomograms using 1102 patients. RESULTS: Among the 2606 patients, 90 had main-duct type, 900 had branch-duct type, and 1616 had mixed-type IPMN. Pathologic results revealed 1628 low-grade dysplasia, 476 high-grade dysplasia, and 502 invasive carcinoma. Location, cyst size, duct dilatation, and mural nodule were selected to construct the nomogram. AUC of this nomogram was higher than the American nomogram (0.691 vs. 0.664, p = 0.014) and comparable with the Korean/Japanese nomogram (0.659 vs 0.653, p = 0.255). CONCLUSIONS: A novel nomogram based on radiologic findings of IPMN is competitive for predicting risk of malignancy. This nomogram would be clinically helpful in circumstances where tumor markers are not available. The nomogram is freely available at http://statgen.snu.ac.kr/software/nomogramIPMN.

3.
HPB (Oxford) ; 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33814298

RESUMO

BACKGROUND: To improve the prognostic accuracy of the 8th edition of the American Joint Committee on Cancer (AJCC) staging system for intrahepatic cholangiocarcinoma (ICC) with establishment and validation of a modified TNM (mTNM) staging system. METHODS: Data on patients who underwent curative-intent resection for ICC was collected from 15 high-volume centers worldwide (n = 643). An external validation dataset was obtained from the SEER registry (n = 797). The mTNM staging system was proposed by redefining T categories, and incorporating the recently proposed N status as N0 (no lymph node metastasis [LNM]), N1 (1-2 LNM) and N2 (≥3 LNM). RESULTS: The 8th AJCC TNM staging system failed to stratify overall survival (OS) of stage II versus IIIA, stage IIIB versus IV, as well as overall stage III versus IV among all patients from the two databases, as well as stage I versus II, and stage III versus III among patients who had ≥6 LNs examined. There was a monotonic decrement in survival based on the proposed mTNM staging classification among patients derived from both the multi-institutional (Median OS, stage I 69.8 vs. II 37.1 vs. III 18.9 vs. IV 16.4 months, all p < 0.05), and SEER (Median OS, stage I 87.0 vs. II 29.3 vs. III 17.7 vs. IV 14.2 months, all p < 0.05) datasets, which was also verified among patients who had ≥6 lymph node harvested from both databases. CONCLUSION: The modified TNM staging system for ICC using the new T and N definitions provided an improved means to stratify patients relative to long-term OS versus the 8th AJCC staging.

4.
Ann Surg Oncol ; 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33791900

RESUMO

INTRODUCTION: To implement a mastery-based robotic surgery curriculum using virtual reality (VR) and inanimate reality (IR) drills at multiple Complex General Surgical Oncology (CGSO) fellowships. PATIENTS AND METHODS: A prospective study of curriculum feasibility and efficacy was conducted at four CGSO fellowship sites. All sites had simulators, and kits were provided to perform 19 biotissue drills. Fellows from three non-UPMC sites (n = 15) in 2016-2018 were compared with fellows from University of Pittsburgh (UPMC; n = 15) where the curriculum was validated in 2014-2018. RESULTS: All fellows completed the pre- and post-test. There was no difference in pre-test scores between UPMC and non-UPMC sites. Only 7 of 15 non-UPMC fellows completed the VR curriculum (47% compliance) compared with all 15 UPMC fellows completing the VR curriculum (100% compliance). UPMC had higher curriculum times (217 versus 93 mins) and % mastery (86% versus 55%). Time spent on curriculum was associated with % mastery (p = 0.01). Both groups showed improvement between pre- and post-test. Post-test VR scores trended higher for UPMC (221 versus 180). Between the non-UPMC sites, there was a difference in compliance (p = 0.03) and % mastery (p = 0.03). Zero non-UPMC fellows performed the biotissue drills, while five contemporary UPMC fellows completed 253 biotissue drills. Approximately 140 UPMC faculty and 300 staff hours were spent on the pilot. CONCLUSIONS: A proficiency curriculum can result in improved robotic console skills. However, multiple barriers to implementation potentially exist, including availability of simulators, availability of a training robot, on-site support staff, and universal buy-in from fellows, faculty, and leadership.

5.
Anal Chem ; 93(10): 4441-4448, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33651586

RESUMO

An effective and reversible tuning of the intensity of surface-enhanced Raman scattering (SERS) of nonelectroactive molecules at nonresonance conditions by electrochemical means has been developed on plasmonic molecular nanojunctions formed between Au@Ag core-shell nanoparticles (NPs) and a gold nanoelectrode (AuNE) modified with a self-assembled monolayer. The Au@Ag nanoparticle on nanoelectrode (NPoNE) structures are formed in situ by the electrochemical deposition of Ag on AuNPs adsorbed on the AuNE and can be monitored by both the electrochemical current and SERS signals. Instead of introducing molecular changes by the applied electrode potential, the highly effective SERS intensity tuning was achieved by the chemical composition transformation of the ultrathin Ag shell from metallic Ag to insulating AgCl. The electrode potential-induced electromagnetic enhancement (EME) tuning in the Au@Ag NPoNE structure has been confirmed by finite-difference time-domain simulations. Moreover, the specific Raman band associated with Ag-molecule interaction can also be tuned by the electrode potential. Therefore, we demonstrated that the electrode potential could effectively and reversibly modulate both EME and chemical enhancement in Au@Ag NPoNE structures.

6.
Acta Biochim Biophys Sin (Shanghai) ; 53(4): 430-437, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33686403

RESUMO

Resveratrol (RES) protects myocardial cells from hypoxia/reoxygenation (H/R)-caused injury. However, the mechanism of this effect has not been clarified. Thus, in this study, we aimed to determine whether RES attenuates H/R-induced cell necroptosis by inhibiting the tumor necrosis factor-alpha (TNF-α)/receptor-interacting protein kinase 1 (RIP1)/RIP3/mixed-lineage kinase domain-like (MLKL) signaling pathway. Rat myocardial ischemia/reperfusion (I/R) models and H/R-injured cell models were constructed. Our study showed that myocardial H/R injury significantly increased the levels of TNF-α, RIP1, RIP3, and p-MLKL/MLKL by western blot analysis. Cell viability assay and 4,6-dianmidino-2-phenylindole (DAPI)-propidium iodide staining showed that the cell viability was decreased, and necroptosis was increased after myocardial H/R injury. The expressions of TNF-α, RIP1, RIP3, and p-MLKL/MLKL in H/R myocardial cells treated with different concentrations of RES were significantly downregulated. In addition, we also found that the cell viability was increased and necroptosis was decreased in dose-dependent manners when H/R-injured cells were treated with RES. In addition, the enhanced effect of TNF-α on necroptosis in myocardial H/R-injured cells was improved by RES, and the effect of RES was confirmed in vivo in I/R rats. This study also showed that RES suppresses necroptosis in H9c2 cells, which may occur through the inhibition of the TNF-α/RIP1/RIP3/MLKL signaling pathway. Our data suggest that necroptosis is a promising therapeutic target and may be a promising therapeutic target for the treatment of myocardial I/R injury.

7.
Sleep Breath ; 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33754249

RESUMO

BACKGROUND: The outbreak of Coronavirus Disease-2019 (COVID-19) caused great psychological distress often with comorbid insomnia. Insomnia is common in patients with COVID-19 admitted to mobile cabin hospitals. Insomnia may lead to immune dysfunction, a condition not conducive to recovery from COVID-19. The use of sedative-hypnotic drugs is limited by their inhibitory effect on the respiratory system. A paucity of research is available regarding psychotherapy interventions to improve insomnia symptoms among  patients with COVID-19. In the general population, sleep problems are more common in women than in men; insomnia in women patients requires special attention. The aim of this study was to develop simplified-cognitive behavioral therapy for insomnia (S-CBTI) for patients with COVID-19 and comorbid insomnia symptoms and to verify its effectiveness through a self-control trial. A second aim was to compare the effectiveness of S-CBTI between acute and chronic insomnia among women with COVID-19 and comorbid insomnia symptoms in Wuhan Jianghan Cabin Hospital. METHODS: S-CBTI consisted of education on COVID-19 and sleep hygiene, stimulus control, sleep restriction, and self-suggestion relaxation training over a period of two consecutive weeks. Of 67 women, 66 completed psychological intervention and baseline and post-intervention assessments. There were 31 women with acute insomnia and 35 with chronic insomnia. The Insomnia Severity Index (ISI) score and self-compiled sleep data were assessed at baseline and post-intervention, and subjective sleep evaluations were assessed at days 4, 7, 12, and 14. RESULTS: The ISI score, sleep latency, night sleep time, and sleep efficiency were statistically significantlly improved from baseline to post-intervention by paired T-test. After the intervention, the mean ISI score of the acute insomnia group was lower than that of the chronic insomnia group. The reduction of the ISI score and the improvement of sleep time from baseline to post-intervention in the acute insomnia group were greater than those in the chronic insomnia group. Utilization of sedative-hypnotic drugs in the acute insomnia group was less than that in the chronic insomnia group, and the difference was statistically significant. CONCLUSIONS: S-CBTI can improve the insomnia symptoms of women with COVID-19 in mobile cabin hospitals, especially for stress-related acute insomnia.

8.
Invest New Drugs ; 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33710464

RESUMO

G-quadruplexes (G4s) are DNA or RNA structures formed by guanine-rich repeating sequences. Recently, G4s have become a highly attractive therapeutic target for BRCA-deficient cancers. Here, we show that a substituted quinolone amide compound, MTR-106, stabilizes DNA G-quadruplexes in vitro. MTR-106 displayed significant antiproliferative activity in homologous recombination repair (HR)-deficient and PARP inhibitor (PARPi)-resistant cancer cells. Moreover, MTR-106 increased DNA damage and promoted cell cycle arrest and apoptosis to inhibit cell growth. Importantly, its oral and i.v. administration significantly impaired tumor growth in BRCA-deficient xenograft mouse models. However, MTR-106 showed modest activity against talazoparib-resistant xenograft models. In rats, the drug rapidly distributes to tissues within 5 min, and its average concentrations were 12-fold higher in the tissues than in the plasma. Overall, we identified MTR-106 as a novel G-quadruplex stabilizer with high tissue distribution, and it may serve as a potential anticancer agent.

9.
J Nerv Ment Dis ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33660687

RESUMO

ABSTRACT: Poststroke depression (PSD) is the most frequent and important neuropsychiatric problem afflicting these patients. Anemia is common in many of these individuals presenting with acute stroke. This study determined whether there is a relationship between anemia on hospital admission and PSD. Two hundred eighty-four acute stroke patients were included in the study. Among them, there were 88 PSD patients, whereas another 196 were non-PSD patients. Clinical depression symptoms were diagnosed according to DSM-4 (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) criteria and a HAMD-17 (the 17-item Hamilton Depression Scale) score ≥8 at 1 month after stroke. In the PSD patients, 27.3% of them presented with anemia, whereas only 12.8% of the non-PSD patients had this condition. There was a negative correlation between hemoglobin level and HAMD-17 score in all patients. A binary logistic regression analysis revealed that anemia was independently associated with PSD after adjustment for sex, National Institutes of Health Stroke Scale scores, mRS (modified Rankin Scale) scores, BI (Barthel Index) scores, RBC (red blood cell), and hematocrit. In conclusion, anemia at admission is associated with PSD seen in these patients 1 month later. Therefore, anemia is a possible predictor of PSD.

10.
Int J Pharm ; 599: 120449, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33711472

RESUMO

Intracellular pathogens pose serious challenges to the public health worldwide. Lysin, peptidoglycan hydrolase from phage, is promising alternative to conventional antibiotics because of its high bactericidal activity and low risk of resistance. However, most proteinaceous lysins cannot penetrate the mammalian cell membrane because of size exclusion. Previously, we reported a broad-spectrum chimeric lysin, ClyR, with a cysteine, histidine-dependent amidohydrolase/peptidase catalytic domain from PlyC lysin and an SH-3b cell-wall binding domain from PlySs2 lysin. Herein, we further report that a novel internal cell-penetrating peptide (CPP) is predicted in the junction region of the two constitutive domains of ClyR, mediated by which ClyR can be internalized by epithelial cells through caveolin-dependent endocytosis to target intracellular pathogens. Residues K153, P154, R169, and R188 of the internal CPP were found to be essential for ClyR-mediated internalization and intracellular killing. RNA-seq analysis further showed that there are minor differences in transcript and metabolic profiles from epithelial cells exposed to 100 µg/ml ClyR for 24 h. Taken together, our findings demonstrate a novel mechanism of internalization by ClyR, providing new insights into the rational designing of the next-generation lysins to target both extracellular and intracellular pathogens.

12.
Adv Mater ; 33(13): e2008540, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33645863

RESUMO

Nanotheranostic agents of gold nanomaterials in the second near-infrared (NIR-II) window have attracted significant attention in cancer management, owing to the reduced background signal and deeper penetration depth in tissues. However, it is still challenging to modulate the localized surface plasmon resonance (LSPR) of gold nanomaterials from the first near-infrared (NIR-I) to NIR-II region. Herein, a plasmonic modulation strategy of gold nanorods (GNRs) through manganese dioxide coating is developed for NIR-II photoacoustic/magnetic resonance (MR) duplex-imaging-guided NIR-II photothermal chemodynamic therapy. GNRs are coated with silica dioxide (SiO2 ) and then covered with magnesium dioxide (MnO2 ) to obtain the final product of GNR@SiO2 @MnO2 (denoted as GSM). The LSPR peak of GNRs could be tuned by adjusting the thickness of the MnO2 layer. Theoretical simulations reveal that this plasmonic modulation is mainly due to the change of refraction index around the GNRs after coating with the MnO2 layer. Additionally, the MnO2 layer is demonstrated to degrade into Mn2+ ions in response to peroxide and acidic protons in the tumor microenvironment, which allows for MR imaging and chemodynamic therapy. This plasmonic modulation strategy can be adapted to other metal nanomaterials and the construction of a new class of NIR-II nanotheranostics.

13.
mBio ; 12(1)2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33622729

RESUMO

Soil microorganisms are sensitive to temperature in cold ecosystems, but it remains unclear how microbial responses are modulated by other important climate drivers, such as precipitation changes. Here, we examine the effects of six in situ warming and/or precipitation treatments in alpine grasslands on microbial communities, plants, and soil carbon fluxes. These treatments differentially affected soil carbon fluxes, gross primary production, and microbial communities. Variations of soil CO2 and CH4 fluxes across all sites significantly (r > 0.70, P < 0.050) correlated with relevant microbial functional abundances but not bacterial or fungal abundances. Given tight linkages between microbial functional traits and ecosystem functionality, we conclude that future soil carbon fluxes in alpine grasslands can be predicted by microbial carbon-degrading capacities.IMPORTANCE The warming pace in the Tibetan Plateau, which is predominantly occupied by grassland ecosystems, has been 0.2°C per decade in recent years, dwarfing the rate of global warming by a factor of 2. Many Earth system models project substantial carbon sequestration in Tibet, which has been observed. Here, we analyzed microbial communities under projected climate changes by 2100. As the soil "carbon pump," the growth and activity of microorganisms can largely influence soil carbon dynamics. However, microbial gene response to future climate scenarios is still obscure. We showed that the abundances of microbial functional genes, but not microbial taxonomy, were correlated with carbon fluxes and ecosystem multifunctionality. By identifying microbial traits linking to ecosystem functioning, our results can guide the assessment of future soil carbon fluxes in alpine grasslands, a critical step toward mitigating climate changes.

14.
Analyst ; 146(7): 2321-2329, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33623934

RESUMO

Guanine (G) oxidation products, such as 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-oxo-guanine (8-OXOG), have been widely studied as promising biomarkers for DNA oxidative damage. In this work, we develop a new method to detect G oxidative products released from live cells after chromium (vi) ion or hydrogen peroxide treatments by using a glass nanopipette-based flexible gold nanoelectrode (fGNE). Specific response to G oxidative products with high sensitivity can be detected from the fGNE tip through integrated electrochemical measurements and surface-enhanced Raman spectroscopy. The fGNE apex can be positioned very close to the cell membrane noninvasively because of its high flexibility and nanoscale tip size. With the assistance of the electrophoretic force, the fGNEs can effectively collect and detect the G-derived DNA damage products released from individual cells in the cell culture medium with high sensitivity.

15.
Int J Biol Macromol ; 177: 370-382, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33621572

RESUMO

Alhagi honey polysaccharide (AHP) exhibit an excellent immune adjuvant effect, but low bioavailability in the body limits its application. Cationic polymer-modified poly (lactic-co-glycolic acid) (PLGA) nanoparticles have been widely investigated as vaccine delivery systems owing to their excellent antigen-loading efficiency. In this study, three kinds of cationic polymer were used to coat AHP-encapsulated PLGA nanoparticles (AHPP) to build positively charged antigen carriers. Among them, H5N1-loaded PEI-AHPP formulation could induce highest hemagglutination inhibition (HI) titer, IgG-subtype, and cytokines, activated dendritic cells (DCs) in lymph nodes, and CD3e+CD4+ and CD3e+CD8a+ T cells in the spleen of immunized mice. PEI-AHPP could stimulate DCs to highly express MHCI and MHCII molecules and had good antigen slow-release effect at the injected site along with lymph node targeting. These findings demonstrate that PEI-AHPP has the potential to be an effective adjuvant to induce strong and long-lasting Th1 and Th2 mixed immune responses.

16.
Virol Sin ; 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559831

RESUMO

Human respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract illness (LRTI), and no vaccine against LRTI has proven to be safe and effective in infants. Our study assessed attenuated recombinant RSVs as vaccine candidates to prevent RSV infection in mice. The constructed recombinant plasmids harbored (5' to 3') a T7 promoter, hammerhead ribozyme, RSV Long strain antigenomic cDNA with cold-passaged (cp) mutations or cp combined with temperature-sensitive attenuated mutations from the A2 strain (A2cpts) or further combined with SH gene deletion (A2cptsΔSH), HDV ribozyme (δ), and a T7 terminator. These vectors were subsequently co-transfected with four helper plasmids encoding N, P, L, and M2-1 viral proteins into BHK/T7-9 cells, and the recovered viruses were then passaged in Vero cells. The rescued recombinant RSVs (rRSVs) were named rRSV-Long/A2cp, rRSV-Long/A2cpts, and rRSV-Long/A2cptsΔSH, respectively, and stably passaged in vitro, without reversion to wild type (wt) at sites containing introduced mutations or deletion. Although rRSV-Long/A2cpts and rRSV-Long/A2cptsΔSH displayed  temperature-sensitive (ts) phenotype in vitro and in vivo, all rRSVs were significantly attenuated in vivo. Furthermore, BALB/c mice immunized with rRSVs produced Th1-biased immune response, resisted wtRSV infection, and were free from enhanced respiratory disease. We showed that the combination of ΔSH with attenuation (att) mutations of cpts contributed to improving att phenotype, efficacy, and gene stability of rRSV. By successfully introducing att mutations and SH gene deletion into the RSV Long parent and producing three rRSV strains, we have laid an important foundation for the development of RSV live attenuated vaccines.

17.
Cell Death Dis ; 12(2): 183, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589588

RESUMO

Monotherapy with poly ADP-ribose polymerase (PARP) inhibitors results in a limited objective response rate (≤60% in most cases) in patients with homologous recombination repair (HRR)-deficient cancer, which suggests a high rate of resistance in this subset of patients to PARP inhibitors (PARPi). To overcome resistance to PARPi and to broaden their clinical use, we performed high-throughput screening of 99 anticancer drugs in combination with PARPi to identify potential therapeutic combinations. Here, we found that GSK3 inhibitors (GSK3i) exhibited a strong synergistic effect with PARPi in a panel of colorectal cancer (CRC) cell lines with diverse genetic backgrounds. The combination of GSK3ß and PARP inhibition causes replication stress and DNA double-strand breaks, resulting in increased anaphase bridges and abnormal spindles. Mechanistically, inhibition or genetic depletion of GSK3ß was found to impair the HRR of DNA and reduce the mRNA and protein level of BRCA1. Finally, we demonstrated that inhibition or depletion of GSK3ß could enhance the in vivo sensitivity to simmiparib without toxicity. Our results provide a mechanistic understanding of the combination of PARP and GSK3 inhibition, and support the clinical development of this combination therapy for CRC patients.

18.
BMC Geriatr ; 21(1): 140, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33632136

RESUMO

BACKGROUND: Although isolated distal deep vein thrombosis (IDDVT) is a clinical complication for acute ischemic stroke (AIS) patients, very few clinicians value it and few methods can predict early IDDVT. This study aimed to establish and validate an individualized predictive nomogram for the risk of early IDDVT in AIS patients. METHODS: This study enrolled 647 consecutive AIS patients who were randomly divided into a training cohort (n = 431) and a validation cohort (n = 216). Based on logistic analyses in training cohort, a nomogram was constructed to predict early IDDVT. The nomogram was then validated using area under the receiver operating characteristic curve (AUROC) and calibration plots. RESULTS: The multivariate logistic regression analysis revealed that age, gender, lower limb paralysis, current pneumonia, atrial fibrillation and malignant tumor were independent risk factors of early IDDVT; these variables were integrated to construct the nomogram. Calibration plots revealed acceptable agreement between the predicted and actual IDDVT probabilities in both the training and validation cohorts. The nomogram had AUROC values of 0.767 (95% CI: 0.742-0.806) and 0.820 (95% CI: 0.762-0.869) in the training and validation cohorts, respectively. Additionally, in the validation cohort, the AUROC of the nomogram was higher than those of the other scores for predicting IDDVT. CONCLUSIONS: The present nomogram provides clinicians with a novel and easy-to-use tool for the prediction of the individualized risk of IDDVT in the early stages of AIS, which would be helpful to initiate imaging examination and interventions timely.

19.
Glob Chang Biol ; 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33528033

RESUMO

Subsoils contain >50% of soil organic carbon (SOC) globally yet remain under-investigated in terms of their response to climate changes. Recent evidence suggests that warmer, drier conditions in alpine grasslands induce divergent responses in SOC decomposition and carbon accrual in top- versus subsoils. However, longer term effects on microbial activity (i.e., catabolic respiration vs. anabolic growth) and belowground carbon cycling are not well understood. Here we utilized a field manipulation experiment on the Qinghai-Tibetan Plateau and conducted a 110-day soil incubation with and without 13 C-labeled grass litter to assess microbes' role as both SOC "decomposers" and "contributors" in the top- (0-10 cm) versus subsoils (30-40 cm) after 5 years of warming and drought treatments. Microbial mineralization of both SOC and added litter was examined in tandem with potential extracellular enzyme activities, while microbial biomass synthesis and necromass accumulation were analyzed using phospholipid fatty acids and amino sugars coupled with 13 C analysis, respectively. We found that warming and, to a lesser extent, drought decreased the ratio of inorganic nitrogen (N) to water-extractable organic carbon in the subsoil, intensifying N limitation at depth. Both SOC and litter mineralization were reduced in the subsoil, which may also be related to N limitation, as evidenced by lower hydrolase activity (especially leucine aminopeptidase) and reduced microbial efficiency (lower biomass synthesis and necromass accumulation relative to respiration). However, none of these effects were observed in the topsoil, suggesting that soil microbes became inactive and inefficient in subsoil but not topsoil environments. Given increasing belowground productivity in this alpine grassland under warming, both elevated root deposits and diminished microbial activity may contribute to new carbon accrual in the subsoil. However, the sustainability of plant growth and persistence of subsoil SOC pools deserve further investigation in the long term, given the aggravated N limitation at depth.

20.
Artigo em Inglês | MEDLINE | ID: mdl-33523604

RESUMO

BACKGROUND: Minimally invasive pancreaticoduodenectomy (MIPD) has recently been safely performed by experts, and various methods for resection have been reported. This review summarizes the literature describing surgical approaches for MIPD. METHODS: A systematic literature search of PubMed (MEDLINE) was conducted for studies reporting robotic and laparoscopic pancreaticoduodenectomy; the reference lists of review articles were searched. Of 444 articles yielded, 23 manuscripts describing the surgical approach to dissect around the superior mesenteric artery (SMA), including hand-searched articles, were assessed. RESULTS: Various approaches to dissect around the SMA have been reported. These approaches were categorized according to the direction toward the SMA when initiating dissection around the SMA: anterior approach (two articles), posterior approach (four articles), right approach (16 articles), and left approach (three articles). Thus, many reports used the right approach. Most articles provided a technical description. Some articles showed the advantage of their method in a comparison study. However, these were single-center retrospective studies with a small sample size. CONCLUSIONS: Various approaches for MIPD have been reported; however, few authors have reported the advantage of their methods compared to other methods. Further discussion is needed to clarify the appropriate surgical approach to the SMA during MIPD.

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