Publications by authors named "Toshiyuki Mori"

214 Publications

Fitness of sulfadoxine-resistant Plasmodium berghei harboring a single mutation in dihydropteroate synthase (DHPS).

Acta Trop 2021 Oct 15;222:106049. Epub 2021 Jul 15.

Department of Tropical Medicine and Parasitology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address:

Genetic changes conferring drug resistance are generally believed to impose fitness costs to pathogens in the absence of the drug. However, the fitness of resistant parasites against sulfadoxine/pyrimethamine has been inconclusive in Plasmodium falciparum. This is because resistance is conferred by the complex combination of mutations in dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr), which makes it difficult to separately assess the extent and magnitude of the costs imposed by mutations in dhps and dhfr. To assess the fitness costs imposed by sulfadoxine resistance alone, we generated a transgenic rodent malaria parasite, P. berghei clone harboring an A394G mutation in dhps (PbDHPS-A394G), corresponding to the causative mutation for sulfadoxine resistance in P. falciparum (PfDHPS-A437G). A four-day suppressive test confirmed that the PbDHPS-A394G clone was resistant to sulfadoxine. PbDHPS-A394G and wild-type clones showed similar growth rates and gametocyte production. This observation was confirmed in competitive experiments in which PbDHPS-A394G and wild-type clones were co-infected into mice to directly assess the survival competition between them. In the mosquitoes, there were no significant differences in oocyst production between PbDHPS-A394G and wild-type. These results indicate that the PbDHPS-A394G mutation alters the parasites to sulfadoxine resistance but may not impose fitness disadvantages during the blood stages in mice and oocyst formation in mosquitoes. These results partly explain the persistence of the PfDHPS-A437G mutant in the natural parasite populations.
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http://dx.doi.org/10.1016/j.actatropica.2021.106049DOI Listing
October 2021

Isolation of Mutants With Reduced Susceptibility to Piperaquine From a Mutator of the Rodent Malaria Parasite .

Front Cell Infect Microbiol 2021 16;11:672691. Epub 2021 Jun 16.

Department of Tropical Medicine and Parasitology, Faculty of Medicine, Juntendo University, Tokyo, Japan.

Elucidation of the mechanisms of drug resistance in malaria parasites is crucial for combatting the emergence and spread of resistant parasites, which can be achieved by tracing resistance-associated mutations and providing useful information for drug development. Previously, we produced a novel genetic tool, a mutator (PbMut), whose base substitution rate is 36.5 times higher than that of wild-type parasites. Here, we report the isolation of a mutant with reduced susceptibility to piperaquine (PPQ) from PbMut under PPQ pressure by sequential nine-cycle screening and named it PbMut-PPQ-R-P9. The ED of PbMut-PPQ-R-P9 was 1.79 times higher than that of wild-type parasites, suggesting that its PPQ resistance is weak. In the 1 screen, recrudescence occurred in the mice infected with PbMut but not in those infected with wild-type parasites, suggesting earlier emergence of PPQ-resistant parasites from PbMut. Whole-genome sequence analysis of PbMut-PPQ-R-P9 clones revealed that eight nonsynonymous mutations were conserved in all clones, including N331I in , the gene encoding chloroquine resistance transporter (). The PbCRT(N331I) mutation already existed in the parasite population after the 2 screen and was predominant in the population after the 8 screen. An artificially inserted PbCRT(N331I) mutation gave rise to reduced PPQ susceptibility in genome-edited parasites (PbCRT-N331I). The PPQ susceptibility and growth rates of PbCRT-N331I parasites were significantly lower than those of PbMut-PPQ-R-P9, implying that additional mutations in the PbMut-PPQ-R9 parasites could compensate for the fitness cost of the PbCRT(N331I) mutation and contribute to reduced PPQ susceptibility. In summary, PbMut could serve as a novel genetic tool for predicting gene mutations responsible for drug resistance. Further study on PbMut-PPQ-R-P9 could identify genetic changes that compensate for fitness costs owing to drug resistance acquisition.
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http://dx.doi.org/10.3389/fcimb.2021.672691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8242943PMC
July 2021

Parenchymal-sparing approaches for resection of tumors located in the paracaval portion of the caudate lobe of the liver-utility of limited resection and central hepatectomy.

Langenbecks Arch Surg 2021 Jun 1. Epub 2021 Jun 1.

Department of Hepato-Biliary-Pancreatic Surgery, Kyorin University Hospital, 6-20-2 Shinkawa, Mitaka City, Tokyo, 181-8611, Japan.

Purpose: Resection of liver cancer involving the paracaval portion (PC) of the caudate lobe is challenging because the PC is located deepest in the liver. This study aimed to elucidate the utility of two parenchymal-sparing approaches of limited resection and central hepatectomy for resecting tumors located in the PC.

Methods: In 2018 and 2020, 12 out of 143 patients underwent hepatectomy for tumors located in the PC of the liver. In six patients, limited resection (LR) of the PC after full mobilization of the liver off the inferior vena cava (IVC) was performed for tumors excluding the hilar plate or large hepatic veins (large HVs), including major hepatic veins or thick short hepatic veins. In six patients, central hepatectomy (CH) using liver tunnel was performed for tumors involving or close to the hilar plate and/or large HVs.

Results: During CH, the surgical view of the cranial side of the hilar plate was wide enough to perform combined resection of the large HVs in front of the IVC. Five of the six CHs were performed with resection of the LHVs. No LRs were accompanied with resection of the LHVs. The CH was associated with longer Pringle's time (76 min vs. 29.5 min, p = 0.015) and blood loss (1104 ml vs. 370 ml, p = 0.041). The preserved liver parenchyma volumes were 82% and 95% of the total liver volume after CH and LR, respectively.

Conclusion: Our parenchymal-sparing approach for resection of liver cancer located in the PC is feasible for curative resection.
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http://dx.doi.org/10.1007/s00423-021-02220-xDOI Listing
June 2021

The Rubisco small subunits in the green algal genus Chloromonas provide insights into evolutionary loss of the eukaryotic carbon-concentrating organelle, the pyrenoid.

BMC Ecol Evol 2021 01 25;21(1):11. Epub 2021 Jan 25.

Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

Background: Pyrenoids are protein microcompartments composed mainly of Rubisco that are localized in the chloroplasts of many photosynthetic organisms. Pyrenoids contribute to the CO-concentrating mechanism. This organelle has been lost many times during algal/plant evolution, including with the origin of land plants. The molecular basis of the evolutionary loss of pyrenoids is a major topic in evolutionary biology. Recently, it was hypothesized that pyrenoid formation is controlled by the hydrophobicity of the two helices on the surface of the Rubisco small subunit (RBCS), but the relationship between hydrophobicity and pyrenoid loss during the evolution of closely related algal/plant lineages has not been examined. Here, we focused on, the Reticulata group of the unicellular green algal genus Chloromonas, within which pyrenoids are present in some species, although they are absent in the closely related species.

Results: Based on de novo transcriptome analysis and Sanger sequencing of cloned reverse transcription-polymerase chain reaction products, rbcS sequences were determined from 11 strains of two pyrenoid-lacking and three pyrenoid-containing species of the Reticulata group. We found that the hydrophobicity of the RBCS helices was roughly correlated with the presence or absence of pyrenoids within the Reticulata group and that a decrease in the hydrophobicity of the RBCS helices may have primarily caused pyrenoid loss during the evolution of this group.

Conclusions: Although we suggest that the observed correlation may only exist for the Reticulata group, this is still an interesting study that provides novel insight into a potential mechanism determining initial evolutionary steps of gain and loss of the pyrenoid.
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http://dx.doi.org/10.1186/s12862-020-01733-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853309PMC
January 2021

Direct splenic vein reconstruction combined with resection of the portal vein/superior mesenteric vein confluence during pancreaticoduodenectomy.

Langenbecks Arch Surg 2021 Aug 22;406(5):1691-1695. Epub 2021 Jan 22.

Department of Hepato-Biliary-Pancreatic Surgery, Kyorin University Hospital, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Purpose: Splenic vein (SV) ligation combined with portal vein (PV)/superior mesenteric vein (SMV) confluence resection during pancreaticoduodenectomy (PD) is reported to cause left-side portal hypertension (LPH). The purpose of this study was to present our technique of the SV reconstruction and to evaluate the surgical outcomes with/without SV ligation during PD.

Methods: Twenty-four patients undergoing PD with PV and/or SMV resection and being followed over 4 months after surgery between March 2013 and December 2019 in our hospital were evaluated. Resection of the PV/SMV confluence were performed in 14, and SV reconstruction was successfully performed in 3. Presence of LPH was assessed by examining changes in splenic volume, newly venous collateral formation, and platelet counts before and 4-8 months after PD. Surgical technique is the direct anastomosis between SV and PV.

Results: Splenic volume ratio was significantly higher in the SV ligation group (n = 11) than in the SV preservation group (n = 13) (median (range) 1.11 (0.57-1.62) vs. 1.68 (1.05-2.22), p < 0.01), but no significant differences were found in the incidence of newly formed venous collaterals or platelet counts between groups.

Conclusion: SV ligation may represent the cause of LPH after PD combined with resection of PV/SMV confluence. Our simple procedure may help decrease the incidence of LPH.
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http://dx.doi.org/10.1007/s00423-020-02064-xDOI Listing
August 2021

Ex vivo susceptibility of Plasmodium falciparum to antimalarial drugs in Northern Uganda.

Parasitol Int 2021 Apr 25;81:102277. Epub 2020 Dec 25.

Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address:

In Uganda, artemether-lumefantrine was introduced as an artemisinin-based combination therapy (ACT) for malaria in 2006. We have previously reported a moderate decrease in ex vivo efficacy of lumefantrine in Northern Uganda, where we also detected ex vivo artemisinin-resistant Plasmodium falciparum. Therefore, it is necessary to search for candidate partner alternatives for ACT. Here, we investigated ex vivo susceptibility to four ACT partner drugs as well as quinine and chloroquine, in 321 cases between 2013 and 2018. Drug-resistant mutations in pfcrt and pfmdr1 were also determined. Ex vivo susceptibility to amodiaquine, quinine, and chloroquine was well preserved, whereas resistance to mefloquine was found in 45.8%. There were few cases of multi-drug resistance. Reduced sensitivity to mefloquine and lumefantrine was significantly associated with the pfcrt K76 wild-type allele, in contrast to the association between chloroquine resistance and the K76T allele. Pfmdr1 duplication was not detected in any of the cases. Amodiaquine, a widely used partner drug for ACT in African countries, may be the first promising alternative in case lumefantrine resistance emerges. Therapeutic use of mefloquine may not be recommended in this area. This study also emphasizes the need for sustained monitoring of antimalarial susceptibility in Northern Uganda to develop proper treatment strategies.
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http://dx.doi.org/10.1016/j.parint.2020.102277DOI Listing
April 2021

Emergence of artemisinin-resistant Plasmodium falciparum with kelch13 C580Y mutations on the island of New Guinea.

PLoS Pathog 2020 12 15;16(12):e1009133. Epub 2020 Dec 15.

Department of Tropical Medicine and Parasitology, Juntendo University Faculty of Medicine, Tokyo, Japan.

The rapid and aggressive spread of artemisinin-resistant Plasmodium falciparum carrying the C580Y mutation in the kelch13 gene is a growing threat to malaria elimination in Southeast Asia, but there is no evidence of their spread to other regions. We conducted cross-sectional surveys in 2016 and 2017 at two clinics in Wewak, Papua New Guinea (PNG) where we identified three infections caused by C580Y mutants among 239 genotyped clinical samples. One of these mutants exhibited the highest survival rate (6.8%) among all parasites surveyed in ring-stage survival assays (RSA) for artemisinin. Analyses of kelch13 flanking regions, and comparisons of deep sequencing data from 389 clinical samples from PNG, Indonesian Papua and Western Cambodia, suggested an independent origin of the Wewak C580Y mutation, showing that the mutants possess several distinctive genetic features. Identity by descent (IBD) showed that multiple portions of the mutants' genomes share a common origin with parasites found in Indonesian Papua, comprising several mutations within genes previously associated with drug resistance, such as mdr1, ferredoxin, atg18 and pnp. These findings suggest that a P. falciparum lineage circulating on the island of New Guinea has gradually acquired a complex ensemble of variants, including kelch13 C580Y, which have affected the parasites' drug sensitivity. This worrying development reinforces the need for increased surveillance of the evolving parasite populations on the island, to contain the spread of resistance.
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http://dx.doi.org/10.1371/journal.ppat.1009133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771869PMC
December 2020

Clinical impact of Endoscopic Surgical Skill Qualification System (ESSQS) by Japan Society for Endoscopic Surgery (JSES) for laparoscopic distal gastrectomy and low anterior resection based on the National Clinical Database (NCD) registry.

Ann Gastroenterol Surg 2020 Nov 31;4(6):721-734. Epub 2020 Aug 31.

Department of Surgery Kitasato University Kitasato Institute Hospital Tokyo Japan.

Aim: This study aimed to evaluate the association between surgeons certified via the Endoscopic Surgical Skill Qualification System (ESSQS) of the Japan Society for Endoscopic Surgery (JSES) and surgical outcomes of laparoscopic distal gastrectomy (LDG) and laparoscopic low anterior resection (LLAR).

Methods: Japanese National Clinical Database data on the patients undergoing LDG and LLAR between 2014-2016 were analyzed retrospectively. The proportion of cases performed by ESSQS-certified surgeons was calculated for each procedure, and clinicopathological factors with or without participation of ESSQS-certified surgeons as an operator were assessed. Then, effects of operations performed by ESSQS-certified surgeons on short-term patient outcomes were analyzed using generalized estimating equations logistic regression analysis.

Results: There were 110 610 and 65 717 patients who underwent LDG and LLAR, respectively. The operations performed by ESSQS-certified surgeons in each procedure totaled 28 467 (35.3%) and 12 866 (31.2%), respectively. A multivariable logistic regression model showed that odds ratios of mortality for LDG and LLAR performed by ESSQS-certified surgeons were 0.774 (95% CI, 0.566-1.060,  = 0.108) and 0.977 (0.591-1.301,  = 0.514), respectively. Odds ratios for secondary endpoints of anastomotic leakage in LDG and LLAR performed by ESSQS-certified surgeons were 0.835 (95% CI, 0.723-0.964,  = 0.014) and 0.929 (0.860-1.003,  = 0.059), respectively, whereas that of ileus/bowel obstruction for LLAR performed by ESSQS-certified surgeons was 1.265 (1.132-1.415,  < 0.001). There were no significant associations between the two operations performed by ESSQS-certified surgeons and other factors such as mortality and overall complications.

Conclusions: ESSQS certification did not affect postoperative mortality following LDG and LLAR, but annual experience of laparoscopic surgery was associated with it. ESSQS certification may contribute to favorable outcomes regarding anastomotic leakage following LDG and LLAR.
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http://dx.doi.org/10.1002/ags3.12384DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726689PMC
November 2020

Double-Volume Intraoperative Lavage Reduce Bacterial Contamination After Pancreaticoduodenectomy.

Am Surg 2021 Jul 9;87(7):1025-1031. Epub 2020 Dec 9.

Department of Hepato-Biliary-Pancreatic Surgery, Kyorin University Hospital, Japan.

Background: To clarify whether double-volume peritoneal lavage can decrease the risk of clinically relevant postoperative pancreatic fistula after pancreaticoduodenectomy.

Materials And Methods: Forty-nine patients who underwent pancreaticoduodenectomy and intraoperative peritoneal lavage using 6000 mL of saline before abdominal closure were studied retrospectively. Bacterial cultures of the lavage fluid were taken twice, after irrigation using 3000 mL of saline and then after an additional 3000 mL of saline. Bacterial culture of the drainage fluid was taken on day 1, and the relationship between the results of bacterial cultures and clinically relevant postoperative pancreatic fistula was examined.

Results: Double amount of peritoneal lavage significantly decreased the incidence of positive bacterial cultures than single amount of peritoneal lavage (45% vs. 29%, < .05). Multivariate analysis showed that positive bacterial culture of drainage fluid on day 1 and main pancreatic duct size (<3 mm) were independent risk factors for clinically relevant postoperative pancreatic fistula. A positive bacterial culture of the final lavage fluid and preoperative biliary drainage were independent factors related to a positive bacterial culture on day 1.

Discussion: A positive bacterial culture on day 1 is an independent risk factor for clinically relevant postoperative pancreatic fistula during pancreaticoduodenectomy. Double-volume intraperitoneal lavage may be effective for reducing the incidence of clinically relevant postoperative pancreatic fistula.
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http://dx.doi.org/10.1177/0003134820956344DOI Listing
July 2021

A pedunculated adenomyomatous polyp of the bile duct.

Pathol Int 2020 Dec 23;70(12):1034-1036. Epub 2020 Sep 23.

Department of Pathology, Kyorin University School of Medicine, Tokyo, Japan.

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http://dx.doi.org/10.1111/pin.13024DOI Listing
December 2020

Current status of laparoscopic bariatric/metabolic surgery in Japan: The sixth nationwide survey by the Japan Consortium of Obesity and Metabolic Surgery.

Asian J Endosc Surg 2021 Apr 21;14(2):170-177. Epub 2020 Jul 21.

Oita University, Oita, Japan.

Introduction: Laparoscopic bariatric procedures have been performed in Japan since 2000. Laparoscopic sleeve gastrectomy (LSG) has been fully covered by National Health Insurance since 2014, and it has been increasingly performed recently. The Japan Consortium of Obesity and Metabolic Surgery conducts a nationwide survey on laparoscopic bariatric/metabolic surgery every 2 years.

Methods: The survey was sent by post or email to 97 Japanese institutions in January 2020.

Results: From 2000 to 2019, a total of 3669 laparoscopic bariatric/metabolic procedures were performed in 64 institutions. The most popular procedure was LSG (n = 2866), followed by LSG with duodenojejunal bypass (LSG-DJB, n = 337) and laparoscopic Roux-en-Y gastric bypass (LRYGB, n = 280). Morbidity and reoperation rates were, respectively, 29.8% and 11.8% for LRYGB, 16.8% and 2.8% for LSG, and 13.6% and 6.6% for LSG-DJB. At 5 years after the procedures, the percentage of excess weight loss was 78% for LRYGB, 66% for LSG, and 80% for LSG-DJB.

Conclusion: This nationwide survey clearly showed that laparoscopic bariatric/metabolic surgery has been safely and effectively performed for 20 years in Japan.
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http://dx.doi.org/10.1111/ases.12836DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048478PMC
April 2021

Restricted Pollination for Tracing Individual Pollen Tubes in a Pistil.

Methods Mol Biol 2020 ;2160:73-81

Graduate School of Horticulture, Chiba University, Chiba, Japan.

As one of the essential steps to complete sexual reproduction, a pollen tube is precisely guided to an embryo sac to deliver the sperm cells. This ovule targeting by a pollen tube is one of the essential steps in pollen tube guidance. To assess the ovule targeting ability of the pollen tube from a certain mutant line, comparative analysis of pollen tube behaviors between wild-type and mutant genotypes is important. Here, we provide a protocol that traces all pollen tubes germinated from the quartet tetrad in a pistil by restricted pollination and aniline blue staining. By this analysis, statistical comparison between wild-type and the mutant pollen tube functions under the same in vivo condition is possible.
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http://dx.doi.org/10.1007/978-1-0716-0672-8_5DOI Listing
March 2021

Optimal Lymphadenectomy of the Mesopancreas Based on Fluorescence Imaging During Pancreaticoduodenectomy.

J Gastrointest Surg 2021 05 27;25(5):1241-1246. Epub 2020 May 27.

Department of Surgery, Kyorin University, School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Background: Excision of the mesopancreas with lymphadenectomy is an important component of pancreatoduodenectomy. However, the optimal extent of lymphadenectomy remains unclear. Furthermore, accurate description of the mesopancreatic lymphatic pathways is difficult, probably because of the complex anatomy. Intestinal derotation simplifies the anatomy and facilitates both examination of lymphatic flow and the surgical procedure. The aim of this study was to evaluate lymphatic flow in the mesopancreas using indocyanine green fluorescence imaging with an intestinal derotation technique, and to clarify the optimal extent of mesopancreas excision and lymphadenectomy in pancreatoduodenectomy.

Methods: Indocyanine green solution (2.5 × 10 mg) was injected into the pancreatic head parenchyma. After intestinal derotation, the spread of indocyanine green was observed using near-infrared imaging.

Results: Participants comprised 10 patients who underwent pancreatoduodenectomy for periampullary neoplasms. With indocyanine green fluorescence imaging, 9 of the 10 patients showed lymphatic flow from the pancreatic head to the superior mesenteric artery via the inferior pancreaticoduodenal artery and first jejunal artery (but not via the second and more distant arteries), with eventual drainage into the paraaortic region.

Conclusions: Lymphatic pathways from the pancreatic head were connected to the superior mesenteric artery via the inferior pancreaticoduodenal artery and first jejunal artery. Excision of the mesopancreas with the inferior pancreaticoduodenal artery and first jejunal artery while preserving the second or more distant arteries appears optimal in pancreatoduodenectomy for periampullary malignancies.
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http://dx.doi.org/10.1007/s11605-020-04619-1DOI Listing
May 2021

Behavior of filamentous temperature-sensitive Z2 (FtsZ2) in the male gametophyte during sexual reproduction processes of flowering plants.

Protoplasma 2020 Jul 3;257(4):1201-1210. Epub 2020 Apr 3.

Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo-shi, Chiba, 271-8510, Japan.

Filamentous temperature-sensitive Z (FtsZ) is a critical division protein in bacteria that functions in forming a Z-ring structure to constrict the cell. Since the establishment of the plastid by endosymbiosis of a cyanobacterium into a eukaryotic cell, division via Z-ring formation has been conserved in the plastids of flowering plants. The FtsZ gene was transferred from the cyanobacterial ancestor of plastids to the eukaryotic nuclear genome during evolution, and flowering plants evolved two FtsZ homologs, FtsZ1 and FtsZ2, which are involved in chloroplast division through distinct molecular functions. Regarding the behaviors of FtsZ in nonphotosynthetic cells, the plastid localization of FtsZ1 proteins in the cytoplasm of microspores and pollen vegetative cells but not in generative cells or sperm cells has been reported. On the other hand, the significant accumulation of FtsZ2 transcripts in generative cells has been reported. However, the synthesis of FtsZ2 in the male gamete has not been investigated. Additionally, FtsZ2 behavior has not been analyzed in pollen, a nonphotosynthetic male tissue. Here, we report FtsZ2 protein behaviors in the male gamete by analyzing the localization patterns of GFP-fused protein at various pollen developmental stages and in gametes during the fertilization process. Our results showed that FtsZ2 localization coincided with that of plastids. FtsZ2 protein in male gametes was almost absent, despite the presence of the transcripts. Moreover, transmission of paternal FtsZ2 transcripts to the zygote and endosperm was not observed.
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http://dx.doi.org/10.1007/s00709-020-01503-2DOI Listing
July 2020

Recovery and stable persistence of chloroquine sensitivity in Plasmodium falciparum parasites after its discontinued use in Northern Uganda.

Malar J 2020 Feb 18;19(1):76. Epub 2020 Feb 18.

Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

Background: Usage of chloroquine was discontinued from the treatment of Plasmodium falciparum infection in almost all endemic regions because of global spread of resistant parasites. Since the first report in Malawi, numerous epidemiological studies have demonstrated that the discontinuance led to re-emergence of chloroquine-susceptible P. falciparum, suggesting a possible role in future malaria control. However, most studies were cross-sectional, with few studies looking at the persistence of chloroquine recovery in long term. This study fills the gap by providing, for a period of at least 6 years, proof of persistent re-emergence/stable recovery of susceptible parasite populations using both molecular and phenotypic methods.

Methods: Ex vivo drug-susceptibility assays to chloroquine (n = 319) and lumefantrine (n = 335) were performed from 2013 to 2018 in Gulu, Northern Uganda, where chloroquine had been removed from the official malaria treatment regimen since 2006. Genotyping of pfcrt and pfmdr1 was also performed.

Results: Chloroquine resistance (≥ 100 nM) was observed in only 3 (1.3%) samples. Average IC values for chloroquine were persistently low throughout the study period (17.4-24.9 nM). Parasites harbouring pfcrt K76 alleles showed significantly lower ICs to chloroquine than the parasites harbouring K76T alleles (21.4 nM vs. 43.1 nM, p-value = 3.9 × 10). Prevalence of K76 alleles gradually increased from 71% in 2013 to 100% in 2018.

Conclusion: This study found evidence of stable persistence of chloroquine susceptibility with the fixation of pfcrt K76 in Northern Uganda after discontinuation of chloroquine in the region. Accumulation of similar evidence in other endemic areas in Uganda could open channels for possible future re-use of chloroquine as an option for malaria treatment or prevention.
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http://dx.doi.org/10.1186/s12936-020-03157-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026951PMC
February 2020

Endoscopic self-expandable metal stent placement for malignant afferent loop obstruction caused by peritoneal recurrence after total gastrectomy.

Int Cancer Conf J 2018 Jul 5;7(3):98-102. Epub 2018 May 5.

Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 Japan.

Afferent loop obstruction (ALO) caused by cancer recurrence after total gastrectomy (TG) can be managed by either surgical or non-surgical treatment. The general condition of patients with recurrent gastric cancer is often poor, so a less invasive non-surgical treatment is desirable. We report the case of a 75-year-old male who had undergone TG for gastric cancer 6 months previously and who presented at our hospital with abdominal pain and vomiting. Abdominal computed tomography scan showed a dilated afferent loop, and additionally a low-density lesion around jejunojejunal anastomosis, suggesting that ALO is associated with peritoneal recurrence. A self-expandable metal stent (SEMS) was endoscopically placed to treat ALO after decompression of the dilated afferent loop using an intestinal tube. He retained a good quality of life until his death due to cancer progression 5 months after the SEMS placement. Our case indicates that SEMS could be a less invasive alternative to surgery, and may confer a better quality of life for patients with ALO due to cancer recurrence after TG. This is the valuable report of case in which endoscopic metallic stent placement succeeded for ALO caused by peritoneal recurrence after TG.
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http://dx.doi.org/10.1007/s13691-018-0328-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6498372PMC
July 2018

See-through observation of malaria parasite behaviors in the mosquito vector.

Sci Rep 2019 02 11;9(1):1768. Epub 2019 Feb 11.

Department of Molecular and Cellular Parasitology, Juntendo University, 2-1-1 Hongo, Bunkyo, Tokyo, Japan.

Although it is known that malaria parasites proliferate in the midgut of mosquito vector, their detailed behaviors, from gamete maturation to formation of next generation sporozoite, have not been fully understood at cellular or molecular level. This is mainly attributed to technical difficulties of dissection and whole-mount observation, of delicate and opaque mosquito body contents. In addition, blood pigment surrounding parasites immediately after blood meal also complicates tracing mosquito-stage parasites. Recent revolutionary studies have overcome such negative factors in tissue observation by clearing organisms. CUBIC reagents succeeded to remove both light scattering and blood pigment from various mouse tissues, and to whole-organ image fluorescence-labeled cell structures. In this study, we utilized the advanced version of CUBIC technology and high sensitivity fluorescent markers for see-through observation of mosquito vector after engulfment of rodent malaria parasites to clarify their behaviors during mosquito stage. As a result, we succeeded to visualize oocysts, sporozoites, female gametes and ookinetes in the mosquito bodies without any dissection.
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http://dx.doi.org/10.1038/s41598-019-38529-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370880PMC
February 2019

The male gamete membrane protein DMP9/DAU2 is required for double fertilization in flowering plants.

Development 2018 11 28;145(23). Epub 2018 Nov 28.

Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo-shi, Chiba 271-8510, Japan

All flowering plants exhibit a unique type of sexual reproduction called 'double fertilization' in which each pollen tube-delivered sperm cell fuses with an egg and a central cell. Proteins that localize to the plasma membrane of gametes regulate one-to-one gamete pairing and fusion between male and female gametes for successful double fertilization. Here, we have identified a membrane protein from generative cells using proteomic analysis and have found that the protein is an ortholog of DUF679 DOMAIN MEMBRANE PROTEIN 9 (DMP9)/DUO1-ACTIVATED UNKNOWN 2 (DAU2). The flowering plant DMP9 proteins analyzed in this study were predicted to have four transmembrane domains and be specifically expressed in both generative and sperm cells. Knockdown of resulted in aborted seeds due to single fertilization of the central cell. Detailed imaging of -knockdown sperm cells during and semi- double fertilization revealed that DMP9 is involved in gamete interaction that leads to correct double fertilization.
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http://dx.doi.org/10.1242/dev.170076DOI Listing
November 2018

Lack of significant recovery of chloroquine sensitivity in Plasmodium falciparum parasites following discontinuance of chloroquine use in Papua New Guinea.

Malar J 2018 Nov 26;17(1):434. Epub 2018 Nov 26.

Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.

Background: Chloroquine treatment for Plasmodium falciparum has been discontinued in almost all endemic regions due to the spread of resistant isolates. Reversal of chloroquine susceptibility after chloroquine discontinuation has been reported in dozens of endemic regions. However, this phenomenon has been mostly observed in Africa and is not well documented in other malaria endemic regions. To investigate this, an ex vivo study on susceptibility to chloroquine and lumefantrine was conducted during 2016-2018 in Wewak, Papua New Guinea where chloroquine had been removed from the official malaria treatment regimen in 2010. Genotyping of pfcrt and pfmdr1 was also performed.

Results: In total, 368 patients were enrolled in this study. Average IC values for chloroquine were 106.6, 80.5, and 87.6 nM in 2016, 2017, and 2018, respectively. These values were not significantly changed from those obtained in 2002/2003 (108 nM). The majority of parasites harboured a pfcrt K76T the mutation responsible for chloroquine resistance. However, a significant upward trend was observed in the frequency of the K76 (wild) allele from 2.3% in 2016 to 11.7% in 2018 (P = 0.008; Cochran-Armitage trend test).

Conclusions: Eight years of chloroquine withdrawal has not induced a significant recovery of susceptibility in Papua New Guinea. However, an increasing tendency of parasites harbouring chloroquine-susceptible K76 suggests a possibility of resurgence of chloroquine susceptibility in the future.
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http://dx.doi.org/10.1186/s12936-018-2585-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6260888PMC
November 2018

Fe-N-C Artificial Enzyme: Activation of Oxygen for Dehydrogenation and Monoxygenation of Organic Substrates under Mild Condition and Cancer Therapeutic Application.

ACS Appl Mater Interfaces 2018 Oct 5;10(41):35327-35333. Epub 2018 Oct 5.

Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Medical School , Southeast University , Nanjing 211189 , China.

Developing highly efficient biomimetic catalysts that directly use O as the terminal oxidant to dehydrogenate and monoxygenate substrates with high selectivity under mild conditions has long been pursued but rarely achieved yet. Herein, we report that heterogeneous Fe-N-C, which is commonly used as an electrocatalyst for oxygen reduction reaction, had unusual biomimetic catalytic activity in both dehydrogenation and monoxygenation of a series of organic molecules (∼100% selectivity) by directly using O. The Fe-N center was verified to be the active site that reductively activated O by spontaneously generating specific reactive oxygen species (ROS) (O, O, and HO). Aided by these ROS, under physiological conditions, the Fe-N-C was further successfully exampled to kill proliferative lung cancer cells. Fe-N-C had several striking superior features with respect to natural enzymes, classical heterogeneous nanozymes, and homogeneous artificial enzymes incapable of working under harsh conditions (extreme pH and high temperature), ease of separation and recycling, and direct use of O. It would open up a new vista of Fe-N-C as an artificial enzyme in biomimetic catalysis, ranging from fundamental simulation of oxidase/oxygenase metabolism to industrial oxidation processes and to disease treatment.
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http://dx.doi.org/10.1021/acsami.8b15540DOI Listing
October 2018

Design of Active Sites on Nickel in the Anode of Intermediate-Temperature Solid Oxide Fuel Cells using Trace Amount of Platinum Oxides.

Chempluschem 2018 Aug 14;83(8):756-768. Epub 2018 Jun 14.

School of Material Science and Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P. R. China.

In recent years, the lowering of the operation temperature of solid oxide fuel cells (SOFCs) has attracted much attention owing to the trade-off between the best performance and the life span of SOFCs. For this challenge, new active sites on the Ni surfaces in a Nickel-Yttria-Stabilized Zirconia (Ni-YSZ) cermet anode of SOFCs have been created by deposition of trace amounts of platinum oxide (PtO ) followed by an activation step of the anode at 1073 K in a hydrogen flow. The internal resistance (IR) free value (185 mA cm at 0.8 V) observed for the single cell with an anode sputtered with a trace amount of PtO (Pt content in anode: from 9 to 91 ppm) at 973 K is conspicuously higher than that of a similar single cell with a nonsputtered cermet anode (85 mA cm ) at 0.8 V and 1073 K. Transmission electron microscopy microanalysis shows that the defect structure is formed on a partially oxidized Ni surface by active Pt species. Also, surface atomistic simulation on NiO (111) predicts the formation of Frenkel defect clusters with Pt cations, which partially cover the Ni surface. The formation of Frenkel defect clusters on the partially oxidized Ni surface (i.e., creation of new active sites for formation of water molecules) promotes the anode reaction, resulting in improvements in the anode performance of SOFC single cells at 973 K. Design of the aforementioned new active sites on Ni through sputtering of trace amounts of PtO provides a great opportunity for "radical innovation" in the design of intermediate-temperature SOFCs.
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http://dx.doi.org/10.1002/cplu.201800170DOI Listing
August 2018

Design of Active Sites on Nickel in the Anode of Intermediate-Temperature Solid Oxide Fuel Cells using Trace Amount of Platinum Oxides.

Chempluschem 2018 Aug 19;83(8):740. Epub 2018 Jun 19.

School of Material Science and Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P. R. China.

Invited for this month's cover is the group of Prof. Dr. Toshiyuki Mori at National Institute for Materials Science (NIMS), Japan. The front cover picture shows the formation of new active sites on Ni in the anode of a solid oxide fuel cell (SOFC), which displays high performance at intermediate temperature. The combination of processing route design, microanalysis, and surface atomistic simulation provides us with a new design paradigm for fabrication of high-performance SOFCs. Read the full text of the article at 10.1002/cplu.201800170.
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http://dx.doi.org/10.1002/cplu.201800280DOI Listing
August 2018

Gastric washing by distilled water can reduce free gastric cancer cells exfoliated into the stomach lumen.

Gastric Cancer 2018 11 25;21(6):998-1003. Epub 2018 Apr 25.

Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Purpose: Intragastric free cancer cells in patients with gastric cancer have rarely been studied. The purpose of this study was to investigate the detection rate of intragastric free cancer cells in gastric washes using two types of solutions during endoscopic examination. We further clarified risk factors affecting the presence of exfoliated free cancer cells.

Methods: A total of 175 patients with gastric cancer were enrolled. Lactated Ringer's solution (N = 89) or distilled water (DW; N = 86) via endoscopic working channel was sprayed onto the tumor surface, and the resultant fluid was collected for cytological examination. We compared the cancer-cell positivity rate between the two (Ringer and DW) groups. We also tested the correlation between cancer-cell positivity and clinicopathological factors in the Ringer group to identify risk factors for the presence of exfoliated cancer cells.

Results: The cancer-cell positivity rate was significantly higher in the Ringer group than that in the DW group (58 vs 6%). Cytomorphology in the Ringer group was well maintained, but not in the DW group. The larger tumor size (≥ 20 mm) and positive lymphatic involvement were significant risk factors of exfoliated free cancer cells.

Conclusions: Cancer cells can be highly exfoliated from the tumor surface into the gastric lumen by endoscopic irrigation in large gastric cancer with lymphatic involvement. Gastric washing by DW can lead to cytoclasis of free cancer cells; therefore, it may minimize the possibility of cancer-cell seeding in procedures carrying potential risks of tumor-cell seeding upon transluminal communication, such as endoscopic full-thickness resection and laparoscopy-endoscopy cooperative surgery.
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http://dx.doi.org/10.1007/s10120-018-0824-zDOI Listing
November 2018

Comparison between endoscopic and laparoscopic removal of gastric submucosal tumor.

Dig Endosc 2018 Apr;30 Suppl 1:7-16

Department of Surgery, Kyorin University School of Medicine, Tokyo, Japan.

Background And Aim: A retrospective study was conducted to compare two resection methods, namely, endoscopic resection (ER) procedures (endoscopic submucosal dissection [ESD], endoscopic muscularis dissection [EMD], and endoscopic full-thickness resection [EFTR]) and laparoscopic resections (LR) (laparoscopic endoscopic cooperative surgery [LECS] and laparoscopic wedge resection).

Methods: Seventy-three patients who underwent ER (N = 33: ESD, N = 4; EMD, N = 15; EFTR, N = 14) or LR (N = 39: LECS, N = 16; wedge resection, N = 23) for gastric submucosal tumor (G-SMT) smaller than 50 mm were included in this study. Patient/tumor characteristics and intra/postoperative factors were compared between the ER and LR groups.

Results: The ER group had a significantly higher percentage of intraluminal growing type of tumor (100% vs 41%) and smaller tumor size (23 vs 33 mm) than the LR group. The ER group had a significantly shorter operative time (93 vs 145 min) and less blood loss (13 vs 30 mL) than the LR group. In the ER group, three patients who had tumors located on the anterior wall of the stomach required laparoscopic closure after EFTR because of difficulty in endoscopic closure of the gastric-wall defect. Postoperative complication rates and duration of postoperative hospital stays did not differ between the two groups.

Conclusions: ER may be technically feasible, safe, less invasive, and oncologically appropriate options for selected patients with the intraluminal growing type of G-SMT smaller than 30 mm. EFTR may be more reasonable alternatives to LR in selected patients with a small G-SMT located on the lesser curvature side.
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http://dx.doi.org/10.1111/den.13010DOI Listing
April 2018

Spontaneous regression of colorectal liver metastasis.

Clin J Gastroenterol 2018 Aug 15;11(4):263-267. Epub 2018 Mar 15.

Department of Surgery, Kyorin University, School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

A 72-year-old woman with advanced ascending colon cancer and an intraductal papillary mucinous neoplasm (IPMN) of the pancreatic head was treated by right hemicolectomy (RHC) and pylorus-preserving pancreaticoduodenectomy (PpPD). Adjuvant chemotherapy was not administered. Multimodal examinations at 5 months after surgery detected a solitary metastatic liver tumor derived from cancer of the ascending colon. Liver resection proceeded at 7 months after the first surgery. A pathological study of a surgical specimen of the liver identified a necrotic nodule that did not contain viable tumor cells. However, an immunohistological study of the hepatic mass indicated metastasis derived from cancer of the ascending colon. These findings were consistent with total necrosis of a liver metastasis of colorectal cancer. The mechanism of spontaneous regression of tumors remains unexplained. In our case, pancreaticoduodenectomy was performed at the same time as right hemicolectomy, which involved a risk of continuous biliary infection after biliary tract reconstruction. A host immune response to chronic biliary tract infection might have been involved in the spontaneous regression of liver metastasis. Spontaneous regression of colorectal liver metastasis is rare, and the mechanism remains unknown. This needs to be investigated in more tissues from patients who have experienced this phenomenon.
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http://dx.doi.org/10.1007/s12328-018-0849-1DOI Listing
August 2018

Effect of Reprimo Down-regulation on Malignant Transformation of Intraductal Papillary Mucinous Neoplasm.

Pancreas 2018 03;47(3):291-295

Objectives: Reprimo gene is a cytoplasmic protein belonging to a family of molecules controlled by p53 that inhibits cell cycle progression. Ectopic expression of Reprimo results in cell cycle arrest at the G2 phase. The aim of this study was to investigate the impact of Reprimo expression on tumorigenesis of intraductal papillary mucinous neoplasm (IPMN).

Methods: Thirty-seven surgical cases of IPMN were collected retrospectively. Twenty-eight patients had benign IPMNs (low-grade dysplasia, n = 18; intermediate-grade dysplasia, n = 10), and the remaining 9 had malignant IPMNs (high-grade dysplasia, n = 4; invasive carcinoma, n = 5). DNA from tumor samples was extracted. DNA methylation patterns of Reprimo were determined by the methods of methylation-specific polymerase chain reaction and immunohistochemistry. The methylation status of Reprimo was compared between benign IPMNs and malignant IPMNs.

Results: The incidence of aberrant DNA methylation of Reprimo was significantly higher in malignant IPMNs than in benign IPMNs (78% vs 32%, P = 0.016). Furthermore, the incidence of immunohistochemical Reprimo expression was significantly lower in malignant IPMNs than in benign IPMNs (22% vs 82%, P = 0.002).

Conclusions: Reprimo methylation was found more frequently in malignant IPMNs. Reprimo methylation is involved in malignant transformation of IPMNs.
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http://dx.doi.org/10.1097/MPA.0000000000001002DOI Listing
March 2018

Establishment of pathological quantitative method for determining undifferentiated component ratio in patients with differentiated/undifferentiated mixed-type early gastric cancer and clinical significance of this ratio.

Gastric Cancer 2018 07 13;21(4):661-671. Epub 2017 Dec 13.

Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Purposes: The purpose of this study was to establish a pathological quantitative method for determining the undifferentiated components ratio (UCR) in patients with differentiated/undifferentiated mixed-type (Mixed-type) early gastric cancer (EGC) and to examine the clinical significance.

Methods: The subjects were 410 patients who underwent surgical resection for EGC with the invasion limited to m or sm1. Analysis 1: In 12 randomly selected patients with Mixed-type cancer, we calculated the area ratio and the ratio of the length ratio using ImageJ and analyzed the correlation between them. Analysis 2: We generated ROC curves, and determined the cutoff UCR on the basis of the predictive risk factors for lymph node metastasis (LNM). Analysis 3: We analyzed the relationship between clinicopathological factors including UCR/length of undifferentiated component (LUC = maximum dimensions of tumor × UCR) and LNM.

Results: Analysis 1: The length ratio can be used as a substitute parameter for the UCR (r = 0.996). Analysis 2: The cutoff UCR as a risk factor for LNM was 58% (sensitivity = 1, 1 - specificity = 0.404). Analysis 3: Lymphovascular invasion (p < 0.0001), UCR ≥58% (p = 0.023), and LUC ≥25 mm (p = 0.005) were identified as significant risk factors for LNM. No LNM was observed in patients with invasion limited to m or sm1 and negativity for lymphovascular invasion and UCR <58% (0/215).

Conclusions: In the patients with Mixed-type EGC, the length ratio of undifferentiated components can be a substitute parameter for the UCR. LNM rarely occurs in patients without lymphovascular invasion and with an UCR <58%. The analysis of the UCR has great significance in determining whether additional surgical resection is required after endoscopic resection.
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http://dx.doi.org/10.1007/s10120-017-0782-xDOI Listing
July 2018

A proposed severity classification system for hepatolithiasis based on an analysis of prognostic factors in a Japanese patient cohort.

J Gastroenterol 2018 Jul 8;53(7):854-860. Epub 2017 Nov 8.

Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Background: Hepatolithiasis frequently results in severe complications. We conducted a cohort study to identify prognostic factors and to establish a hepatolithiasis severity classification system.

Methods: The study cohort comprised 396 patients who were identified through a 1998 nationwide survey and followed up for 18 years or until death. Cox regression analysis was used to identify prognostic factors.

Results: Median survival time of the patients was 308 (range 0-462) months. Of the 396 patients enrolled in the study, 118 (29.8%) died, most frequently from intrahepatic cholangiocarcinoma (25 patients, 21.2%). Age of ≥ 65 years at the time of initial diagnosis [hazard ratio (HR) 3.410], jaundice for ≥ 1 week during follow-up (HR 2.442), intrahepatic cholangiocarcinoma (HR 3.674), and liver cirrhosis (HR 5.061) were shown to be significant risk factors for death from any therapeutic course. The data led to a 3-grade disease severity classification system that incorporates intrahepatic cholangiocarcinoma and liver cirrhosis as major factors and age of ≥ 65 years and jaundice for ≥ 1 week during follow-up as minor factors. Survival rates differed significantly between grades.

Conclusions: The proposed hepatolithiasis severity classification system can be used to assess prognosis and thereby improve patient outcomes.
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http://dx.doi.org/10.1007/s00535-017-1410-6DOI Listing
July 2018

Effect of Carbon Supports on Enhancing Mass Kinetic Current Density of Fe-N/C Electrocatalysts.

Chemistry 2017 Oct 18;23(58):14597-14603. Epub 2017 Sep 18.

Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province, Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Medical School, Southeast University, Nanjing, 211189, China.

The mass kinetic current density (mass J ) of most extensively reported M-N/C catalysts (M represents non-precious metal elements such as Fe, Co, and Cu), a potential alternative to noble metal catalysts in fuel cells, is poorer than that of commercial Pt/C. Thus, deep understanding of the intrinsic roles of carbon supports may contribute to the development of M-N/C catalysts from a practical point of view. Herein, the routinely used carbon supports, i.e. carbon black (CB) and carbon nanotubes (CNT) that have different morphology and crystallinity, were investigated to uncover the factors that affected the mass J of Fe-N/C in electrocatalytic oxygen reduction. When immobilized on CB, the ionic liquids-derived Fe-N/C exhibited an enhanced mass J (4.45 A g at 0.80 V vs. RHE) by a factor of 2.14 times, comparable to that of Pt/C (5.79 A g ) and higher than most reported M-N/C catalysts to our best knowledge. In contrast, the CNT support system showed no improvement. It was revealed that a compatible interface between the Fe-N/C precursors and the carbon supports was vital to ensure in-situ growth of a uniform catalyst layer on the supports during pyrolysis. This subsequently promotes the mass J by exposing more embedded active sites and introducing favorable slit pores for effective mass-diffusion. This work would be promising to address the long-term overlooked challenge of the low mass J of M-N/C catalysts in replacing noble-metal catalysts for practical fuel cell applications.
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http://dx.doi.org/10.1002/chem.201703020DOI Listing
October 2017
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