Metabolic Investigation and Auxiliary Enzyme Modelization of the Pyrrocidine Pathway Allow Rationalization of Paracyclophane-Decahydrofluorene Formation.

Fungal paracyclophane-decahydrofluorene-containing natural products are complex polycyclic metabolites derived from similar hybrid PKS-NRPS pathways. Herein we studied the biosynthesis of pyrrocidines, one representative of this family, by gene inactivation in the producer Sarocladium zeae coupled to thorough metabolic analysis and molecular modeling of key enzymes. We characterized nine pyrrocidines and analogues as well as in mutants a variety of accumulating metabolites with new structures including rare cis-decalin, cytochalasan, and fused 6/15/5 macrocycles. This diversity highlights the extraordinary plasticity of the pyrrocidine biosynthetic gene cluster. From accumulating metabolites, we delineated the scenario of pyrrocidine biosynthesis. The ring A of the decahydrofluorene is installed by PrcB, a membrane-bound cyclizing isomerase, on a PKS-NRPS-derived pyrrolidone precursor. Docking experiments in PrcB allowed us to characterize the active site suggesting a mechanism triggered by arginine-mediated deprotonation at the terminal methyl of the substrate. Next, two integral membrane proteins, PrcD and PrcE, each predicted as a four-helix bundle, perform hydroxylation of the pyrrolidone ring and paracyclophane formation, respectively. Modelization of PrcE highlights a topological homology with vitamin K oxido-reductase and the presence of a disulfide bond. Our results suggest a previously unsuspected coupling mechanism via a transient loss of aromaticity of tyrosine residue to form the strained paracyclophane motif. Finally, the lipocalin-like protein PrcX drives the exo-cycloaddition yielding ring B and C of the decahydrofluorene to afford pyrrocidine A, which is transformed by a reductase PrcI to form pyrrocidine B. These insights will greatly facilitate the microbial production of pyrrocidine analogues by synthetic biology.

Length-controlled hydrophobic CF3-COF as a highly efficient absorbent coating for dual-mode solid-phase microextraction of sixteen polycyclic aromatic hydrocarbons in water samples.

Polycyclic aromatic hydrocarbons (PAHs), a group of seriously hazardous environmental contaminants, have attracted extensive attention due to their carcinogenicity, genotoxicity, mutagenicity, and ubiquity. In this work, the excellent hydrophobic trifluoromethyl-enriched covalent organic framework (CF3-COF) was designed and synthesized as coating of solid-phase microextraction (SPME). The CF3-COF offered a high adsorption selectivity for PAHs, which could be attributed to the multiple interactions between the CF3-COF and PAHs, including hydrophobicity interaction, π-π and H bond interactions. Furthermore, headspace (HS) and direct immersion (DI) dual-mode solid-phase microextraction (HS/DI-SPME) were innovatively integrated as a dual-mode extraction by varying the length of SPME coating on stainless-steel, which could simultaneously and efficiently extract 16 PAHs with different volatile. Amazingly, the proposed strategy achieved fast adsorption for PAHs and shortened the adsorption equilibrium time to 15 min. By further integrating with gas chromatography tandem mass spectrometry (GC-MS/MS), PAHs could be detected in the range of 0.008-0.16 ng mL-1 with a quantitative limit of 0.029-0.47 ng mL-1, respectively. The recoveries of PAHs in water samples ranged from 80.84 to 117.67 %. This work indicates that the dual-mode CF3-COF-SPME is a promising candidate for the enrichment of multiple hazardous substances in complicated samples.

Analysis of the efficacy of sleeve gastrectomy, one-anastomosis gastric bypass, and single-anastomosis sleeve ileal bypass in the treatment of metabolic syndrome.

The objective of this study was to evaluate and compare the effectiveness of three different types of bariatric surgeries, namely, sleeve gastrectomy (SG), one-anastomotic gastric bypass (OAGB), and single anastomosis sleeve ileal (SASI) bypass, in the treatment of metabolic syndrome (MS). The optimal approach for managing MS remains uncertain, and thus this study aimed to provide a recent analysis of the efficacy of these surgical procedures. This retrospective study evaluated data of individuals who underwent SG, OAGB, and SASI bypass. The primary outcome measures included weight, body mass index (BMI), glucolipid metabolic index, and the occurrence of treatment-related complications within 6 to 12 months post-surgery. A total of 324 patients were included in this study. Of these, 264 patients underwent SG, 30 underwent OAGB, and 30 underwent SASI bypass. A significant decrease in weight was observed at the 6-month and 12-month marks following all three surgical procedures. Of these, patients who underwent SASI bypass exhibited the greatest reduction in weight and BMI post-surgery. Furthermore, the SASI bypass was associated with a significantly higher percentage of total weight loss (%TWL) and excess body mass index loss (%EBMIL) compared to SG and OAGB. Patients who underwent OAGB and SASI bypass demonstrated notable improvements in type 2 diabetes mellitus (T2DM). Patients who underwent SASI bypass and OAGB experienced greater postoperative comfort and reported fewer complaints of discomfort compared to the other procedure. Based on the retrospective analysis of the data, SASI bypass was associated with greater reductions in weight and BMI, higher percentages of %TWL and %EBMIL, and better improvement in T2DM compared to SG and OAGB. Therefore, both SASI bypass and OAGB were found to be more effective than SG in the treatment of MS.

A Tandem Regiospecific [3 + 2] Annulation/Ring Cleavage Reaction for the Synthesis of ß-Ketoenamides.

A series of ß-ketoenamines was synthesized from various phenacyl sulfoxides bearing 1-methyl-1H-tetrazole and oximes in moderate to excellent yields. The proposed mechanism involved the generation of α-sulfines from sulfoxides through thermolytic elimination, regiospecific formal [3 + 2] annulations, and elimination of SO2. This protocol provides convenient access to a variety of synthetically valuable N-unprotected ß-enaminones with absolute Z selectivity.

Short C-terminal Musashi-1 proteins regulate pluripotency states in embryonic stem cells.

The RNA-binding protein Musashi-1 (MSI1) regulates the proliferation and differentiation of adult stem cells. However, its role in embryonic stem cells (ESCs) and early embryonic development remains poorly understood. Here, we report the presence of short C-terminal MSI1 (MSI1-C) proteins in early mouse embryos and mouse ESCs, but not in human ESCs, under conventional culture conditions. In mouse embryos and mESCs, deletion of MSI1-C together with full-length MSI1 causes early embryonic developmental arrest and pluripotency dissolution. MSI1-C is induced upon naive induction and facilitates hESC naive pluripotency acquisition, elevating the pluripotency of primed hESCs toward a formative-like state. MSI1-C proteins are nuclear localized and bind to RNAs involved in DNA-damage repair (including MLH1, BRCA1, and MSH2), conferring on hESCs better survival in human-mouse interspecies cell competition and prolonged ability to form blastoids. This study identifies MSI1-C as an essential regulator in ESC pluripotency states and early embryonic development.

120-GBaud 16-QAM silicon photonics IQ modulator for data center interconnection.

We demonstrated all-silicon IQ modulators (IQMs) operating at 120-GBaud 16-QAM with suitable bandwidth, and output power. We required optical signal-to-noise-ratio (rOSNR) that have promising potential to be used in 800-Gbps small-form-factor pluggable transceivers for data center interconnection. First, we tested an IQM chip using discrete drivers and achieved a per-polarization TX output power of -18.74 dBm and an rOSNR of 23.51 dB over a 100-km standard SMF. Notably, a low BER of 1.4e-3 was obtained using our SiP IQM chip without employing nonlinear compensation, optical equalization, or an ultra-wide-bandwidth, high-ENOB OMA. Furthermore, we investigated the performance of a 3D packaged transmitter by emulating its frequency response using an IQM chip, discrete drivers, and a programmable optical filter. With a laser power of 17 dBm, we achieved a per-polarization output power of -15.64 dBm and an rOSNR of 23.35 dB.

Lipidomic study and diagnosis of hepatocellular carcinoma tumor with rapid evaporative ionization mass spectrometry.

Liver cancer is generally considered the leading cause of cancer deaths worldwide, and hepatocellular carcinoma (HCC) contributes to more than 90% of liver cancers. The altered lipid metabolism for rapid cancer cell growth and tumor formation has been frequently proven. In this study, an ambient ionization mass spectrometry technique, rapid evaporative ionization mass spectrometry (REIMS) using a monopolar electric knife, called iKnife, was systematically optimized and employed for ex vivo analysis of 12 human HCC tumor tissue specimens together with the paired paracancerous tissue (PT) and noncancerous liver tissue (NCT) specimens. Nine free fatty acids and 34 phospholipids were tentatively identified according to their extract masses and/or tandem mass spectra. With the help of statistical methods, 7 free fatty acids and 10 phospholipids were distributed differently in 3 types of liver tissue specimens (95% confidence interval). The box plots showed these characterized lipid metabolites varied in PT, HCC, and NCT. Compared with PT and NCT, the upregulations of four common fatty acids FA 18:0, FA 20:4, FA 16:0, and FA 18:1, together with phospholipids PC 36:1, PE 38:3, PE (18:0/20:4), PA (O-36:1), PC (32:1), PC 32:0, PE 34:0, and PC (16:0/18:1), were found in HCC specimens. The sensitivity and specificity of the established statistic model for real-time HCC tumor diagnosis were 100% and 90.5%, respectively. This study demonstrated that the described REIMS technique is a potential method for rapid lipidomic analysis and characterization of HCC tumor tissue.

Biocompatible exosome-modified fibrin gel accelerates the recovery of spinal cord injury by VGF-mediated oligodendrogenesis.

Exosomes show potential for treating patients with spinal cord injury (SCI) in clinical practice, but the underlying repair mechanisms remain poorly understood, and biological scaffolds available for clinical transplantation of exosomes have yet to be explored. In the present study, we demonstrated the novel function of Gel-Exo (exosomes encapsulated in fibrin gel) in promoting behavioural and electrophysiological performance in mice with SCI, and the upregulated neural marker expression in the lesion site suggested enhanced neurogenesis by Gel-Exo. According to the RNA-seq results, Vgf (nerve growth factor inducible) was the key regulator through which Gel-Exo accelerated recovery from SCI. VGF is related to myelination and oligodendrocyte development according to previous reports. Furthermore, we found that VGF was abundant in exosomes, and Gel-Exo-treated mice with high VGF expression indeed showed increased oligodendrogenesis. VGF was also shown to promote oligodendrogenesis both in vitro and in vivo, and lentivirus-mediated VGF overexpression in the lesion site showed reparative effects equal to those of Gel-Exo treatment in vivo. These results suggest that Gel-Exo can thus be used as a biocompatible material for SCI repair, in which VGF-mediated oligodendrogenesis is the vital mechanism for functional recovery.

Surgery for Cronkhite-Canada syndrome complicated with intussusception: A case report and review of literature.

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare nonhereditary disease with a syndrome of multiple gastrointestinal polyps, skin pigmentation, hair loss, and fingernail/toenail dystrophy. Intussusception is a serious condition with an occurrence rate of 5% in adults, which is mainly caused by intestinal tumors or other intestinal occupations. CASE SUMMARY: A 57-year-old woman was admitted to our hospital due to abdominal distension and pain for the past year. Her nausea and vomiting symptoms had been aggravated for the past month. Previous transoral enteroscopy results one year prior showed chronic erosive gastritis protuberans, duodenitis, and jejunitis. She had sparse body hair and brown pigmentation on the skin of her hands and bilateral anterior tibias. The nails of both hands were pale and lacked luster, and the fingernail of her ring finger was longitudinally cracked. Gastroscopy showed extensive diffuse polypoid lump changes in the gastric body and antrum, of 0.5-3 cm in size. Colonoscopy showed multiple polypoid mucosal bulges in the terminal ileum and multiple polyps (0.3-5 cm) throughout the colon. The patient was diagnosed with CCS and underwent partial excision of the polyps, but she refused hormone therapy. One month later, the patient complained of nausea and vomiting, accompanied by abdominal pain and inability to pass gas or stool. Contrast-enhanced computed tomography of the abdomen showed gastrointestinal polyposis and ileocecal intussusception. She underwent stomach and bowel surgery. CONCLUSION: CCS, as a rare disease with poor prognosis, should be treated aggressively. Systematic steroids, immunosuppressive agents, and biological agents were not applied; thus, the patient's symptoms quickly progressed, and intussusception occurred. She had to undergo surgery. Improved compliance may lead to a better prognosis.

Reinforced education by short message service improves the quality of bowel preparation for colonoscopy.

PURPOSE: This study aimed to evaluate the effect of reinforced education (RE) by short message service (SMS) on the bowel preparation quality of patients undergoing colonoscopy. METHODS: Randomized controlled trials (RCTs), conducted on the effect of RE by SMS on bowel preparation for colonoscopy from inception to November 1, 2021, were queried from databases, including PubMed, Web of Science, the Cochrane Library, and EMBASE. After extracting the data, meta-analysis was conducted using Review Manager Software version 5.3. RESULTS: A total of seven RCTs with 5889 patients were subjected to meta-analysis. The rate of adequate bowel preparation in the SMS group (81.7%) was significantly higher than that in the control group (75.7%) (RR: 1.10, 95% CI: 1.03-1.17, p < 0.01). Four studies suggested that RE by SMS significantly reduced the non-attendance rate of patients for scheduled colonoscopy (RR: 0.74, 95% CI: 0.56-0.99, p < 0.05). CONCLUSION: RE by SMS for patients undergoing colonoscopy can significantly improve the quality of bowel preparation and decrease the non-attendance rate of patients for scheduled colonoscopy.

Characteristics and potential malignancy of colorectal juvenile polyps in adults: a single-center retrospective study in China.

BACKGROUND: Colorectal juvenile polyps are rare and generally considered benign in adults. Carcinogenesis or neoplastic changes are rarely mentioned in the literature. We systematically evaluated the characteristics and potential malignancy of colorectal juvenile polyps in adults. METHODS: We retrospectively reviewed the medical records of 103 adults diagnosed with colorectal juvenile polyps from September 2007 to May 2020 at our hospital. The characteristics, endoscopic findings, occurrence of intraepithelial neoplasia, carcinogenesis and diagnostic value of chicken skin mucosa (CSM) were analyzed. RESULTS: The average age of patients with juvenile polyps was 43.2 years (range, 19 to 78 years). A total of 101 patients (101/103, 98.1%) had a single juvenile polyp, and two patients had multiple polyps (107 polyps in total). Polyp sizes ranged from 0.5 to 5 cm. One (1/107, 0.9%) juvenile polyp was cancerous, and 7 (7/107, 6.5%) developed low-grade intraepithelial neoplasia. Neoplasia and cancerization did not appear in the two patients with multiple polyps. A 27-year-old female had a 2-cm polyp with well-differentiated adenocarcinoma in the mucosa in the sigmoid colon with erosion on the surface. CSM was observed adjacent to 17 polyps, which were all located in the rectum and sigmoid colon, and one polyp showed low-grade intraepithelial neoplasia. CONCLUSIONS: Colorectal juvenile polyps occur in a wide range of locations and in variable sizes and numbers. These polyps are solitary in most patients and have neoplastic potential. CSM is not a tumorigenic marker in colorectal juvenile polyps and usually occurs in the distant colorectum. Colorectal juvenile polyps in adults may progress from low-grade intraepithelial neoplasia to high-grade intraepithelial neoplasia and then to carcinoma and should be treated when discovered and regularly followed as colorectal adenomas.

Purification and characterization of anti-phytopathogenic fungi angucyclinone from soil-derived Streptomyces cellulosae.

Actinomycete strain YIM PH20352, isolated from the rhizosphere soil sample of Panax notoginseng collected in WenShang, Yunnan Province, China, exhibited antifungal activity against some phytopathogenic fungi. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as rabelomycin (1) and dehydrorabelomycin (2) based on extensive spectroscopic analyses. Compound 1 exhibited antifungal activity against four tested root-rot pathogens of the Panax notoginseng including Plectosphaerella cucumerina, Alternaria panax, Fusarium oxysporum, and Fusarium solani with the MIC values at 32, 64, 128, and 128 µg/mL, respectively. Compound 2 exhibited antifungal activity against F. oxysporum, P. cucumerina, F. solani, and A. panax with the MIC values at 64, 64, 128, and 128 µg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20352 is Streptomyces cellulosae NBRC 13027 T (AB184265) (99.88%), so strain YIM PH20352 was identified as Streptomyces cellulosae. To the best of our knowledge, this is the first report of rabelomycin and rabelomycin-type antibiotics from Streptomyces cellulosae and their antifungal activity against root-rot pathogens of the Panax notoginseng.

Evi5 is required for Xenopus limb and tail regeneration.

Amphibians such as salamanders and the African clawed frog Xenopus are great models for regeneration studies because they can fully regenerate their lost organs. While axolotl can regenerate damaged organs throughout its lifetime, Xenopus has a limited regeneration capacity after metamorphosis. The ecotropic viral integrative factor 5 (Evi5) is of great interest because its expression is highly upregulated in the limb blastema of axolotls, but remains unchanged in the fibroblastema of post-metamorphic frogs. Yet, its role in regeneration-competent contexts in Xenopus has not been fully analyzed. Here we show that Evi5 is upregulated in Xenopus tadpoles after limb and tail amputation, as in axolotls. Down-regulation of Evi5 with morpholino antisense oligos (Mo) impairs limb development and limb blastema formation in Xenopus tadpoles. Mechanistically, we show that Evi5 knockdown significantly reduces proliferation of limb blastema cells and causes apoptosis, blocking the formation of regeneration blastema. RNA-sequencing analysis reveals that in addition to reduced PDGFα and TGFß signaling pathways that are required for regeneration, evi5 Mo downregulates lysine demethylases Kdm6b and Kdm7a. And knockdown of Kdm6b or Kdm7a causes defective limb regeneration. Evi5 knockdown also impedes tail regeneration in Xenopus tadpoles and axolotl larvae, suggesting a conserved function of Evi5 in appendage regeneration. Thus, our results demonstrate that Evi5 plays a critical role in appendage regeneration in amphibians.

Degradation of endothelial glycocalyx in Tanzanian children with falciparum malaria.

A layer of glycocalyx covers the vascular endothelium serving important protective and homeostatic functions. The objective of this study was to determine if breakdown of the endothelial glycocalyx (eGC) occurs during malaria infection in children. Measures of eGC integrity, endothelial activation, and microvascular reactivity were prospectively evaluated in 146 children: 44 with moderately severe malaria (MSM), 42 with severe malaria (SM), and 60 healthy controls (HC). Biochemical measures of eGC integrity included plasma syndecan-1 and total urinary glycosaminoglycans (GAG). Side-stream dark field imaging was used to quantitatively assess integrity of eGC. Plasma angiopoietin-2 (Ang-2) was measured as a marker of endothelial activation and also as a possible mediator of eGC breakdown. Our results show that urinary GAG, syndecan-1, and Ang-2 were elevated in patients with MSM and SM compared with HC. Syndecan-1 and GAG levels correlated significantly with each other and with plasma Ang-2. The eGC breakdown products also inversely correlated significantly with hemoglobin and platelet count. In the MSM group, imaging results provided further evidence for eGC degradation. Although not correlated with markers of eGC degradation, vascular function (assessed by non-invasive near infrared spectroscopy [NIRS]) demonstrated reduced microvascular reactivity, particularly affecting the SM group. Our findings provide further evidence for breakdown of eGC in falciparum malaria that may contribute to endothelial activation and adhesion of parasitized red blood cells, with reduced nitric oxide formation, and vascular dysfunction.

Idiopathic mesenteric phlebosclerosis associated with long-term oral intake of geniposide.

BACKGROUND: Idiopathic mesenteric phlebosclerosis (IMP) is a rare disease, and its etiology and risk factors remain uncertain. AIM: To investigate the possible influence of Chinese herbal liquid containing geniposide on IMP. METHODS: The detailed formula of herbal liquid prescriptions of all patients was studied, and the herbal ingredients were compared to identify the toxic agent as a possible etiological factor. Abdominal computed tomography (CT) and colonoscopy images were reviewed to determine the extent and severity of mesenteric phlebosclerosis and the presence of findings regarding colitis. The disease CT score was determined by the distribution of mesenteric vein calcification and colon wall thickening on CT images. The drinking index of medicinal liquor was calculated from the daily quantity and drinking years of Chinese medicinal liquor. Subsequently, Spearman's correlation analysis was conducted to evaluate the correlation between the drinking index and the CT disease score. RESULTS: The mean age of the 8 enrolled patients was 75.7 years and male predominance was found (all 8 patients were men). The patients had histories of 5-40 years of oral Chinese herbal liquids containing geniposide and exhibited typical imaging characteristics (e.g., threadlike calcifications along the colonic and mesenteric vessels or associated with a thickened colonic wall in CT images). Calcifications were confined to the right-side mesenteric vein in 6 of the 8 patients (75%) and involved the left-side mesenteric vein of 2 cases (25%) and the calcifications extended to the mesorectum in 1 of them. The thickening of colon wall mainly occurred in the right colon and the transverse colon. The median disease CT score was 4.88 (n = 7) and the median drinking index was 5680 (n = 7). After Spearman's correlation analysis, the median CT score of the disease showed a significant positive correlation with the median drinking index (r = 0.842, P < 0.05). CONCLUSION: Long-term oral intake of Chinese herbal liquid containing geniposide may play a role in the pathogenesis of IMP.

Endothelial glycocalyx degradation and disease severity in Plasmodium vivax and Plasmodium knowlesi malaria.

Degradation of the endothelial glycocalyx is associated with mortality in adult falciparum malaria. However, its role in the pathogenesis of non-falciparum malaria is unknown. In Malaysian patients with knowlesi (n = 200) and vivax (n = 61) malaria, and in healthy controls (n = 50), we measured glycocalyx breakdown products plasma syndecan-1 and urinary glycosaminoglycans, and evaluated correlations with biomarkers of disease severity. Urinary glycosaminoglycans were increased in patients with knowlesi and vivax malaria compared to healthy controls, and in knowlesi malaria were highest in those with severe disease. In knowlesi malaria, plasma syndecan-1 was also highest in those with severe disease, and correlated with markers of endothelial activation (angiopoietin-2, osteoprotegerin, ICAM-1), asymmetric dimethylarginine (ADMA) and impaired microvascular reactivity. Syndecan-1 also correlated with endothelial activation (ICAM-1, angiopoietin-2) and ADMA in vivax malaria. In knowlesi malaria increased syndecan-1 was associated with acute kidney injury, after controlling for age and parasitemia. In knowlesi malaria, the difference in median syndecan-1 between severe and non-severe disease was more marked in females than males. Endothelial glycocalyx degradation is increased in knowlesi and vivax malaria, and associated with disease severity and acute kidney injury in knowlesi malaria. Agents that inhibit glycocalyx breakdown may represent adjunctive therapeutics for severe non-falciparum malaria.

Roles and mechanisms of NRG1 in modulating the pathogenesis of NAFLD through ErbB3 signaling in hepatocytes (NRG1 modulates NAFLD through ErbB3 signaling).

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is an emerging chronic liver disease. However, the underlying mechanisms remained poorly understood. Neuregulin (NRG) family participate in energy metabolism, and might be related to NAFLD. METHODS: L02 cells were exposed to oleic acid to establish a cellular model of NAFLD. We analyzed the NAFLD cells with NRG1 and subsequent ErbB3 siRNA treatment. Cellular total lipid was stained by Oil Red O, while triglyceride content and inflammation markers were measured by enzymatic kits. The expressions of down-stream molecules were evaluated by western blot. RESULTS: In vitro, NRG1 could alleviate the steatosis of NAFLD, and inhibit the expression of IL-6 and TNF-α. The downregulation of ErbB3 aggravated steatosis, improved the levels of triglyceride, IL-6 and TNF-α in NRG1-treated NAFLD. Moreover, NRG1 treatment up-regulated ErbB3 phosphorylation, and increased the expression of PI3K and phosphorylation-AKT. When NRG1-treated NAFLD cells were transfected with ErbB3 siRNA, the expressions of ErbB3, p-ErbB3, p-AKT and PI3K were all reduced. CONCLUSION: NRG1 might play a protective role in the pathogenesis of NAFLD through ErbB3 phosphorylation to modulate the activation of PI3K-AKT pathway. The findings will expand the understanding of the mechanisms of NAFLD, and provide potential therapeutic targets.

Hemosuccus pancreaticus caused by gastroduodenal artery pseudoaneurysm associated with chronic pancreatitis: A case report and review of literature.

BACKGROUND: Hemosuccus pancreaticus is a very rare but severe form of upper gastrointestinal hemorrhage. The most common etiology is peripancreatic pseudoaneurysm secondary to chronic pancreatitis. Due to the rarity of gastroduodenal artery pseudoaneurysms, most of the current literature consists of case reports. Limited knowledge about the disease causes diagnostic difficulty. CASE SUMMARY: A 39-year-old man with a previous history of chronic pancreatitis was hospitalized due to hematemesis and melena for 2 wk, with a new episode lasting 1 d. Two weeks prior, the patient had visited a local hospital for repeated hematemesis and melena. Esophagogastroduodenoscopy indicated hemorrhage in the descending duodenum. The patient was discharged after the bleeding stopped, but hematemesis and hematochezia recurred. Bedside esophago-gastroduodenoscopy showed no obvious bleeding lesion. On admission to our hospital, he had hematemesis, hematochezia, left middle and upper abdominal pain, severe anemia, and elevated blood amylase. After admission, intermittent hematochezia was observed. Abdominal contrast-enhanced computed tomography revealed a pseudoaneurysm in the pancreas head. Angiography confirmed the diagnosis of gastroduodenal artery pseudoaneurysm. The pseudoaneurysm was successfully embolized with a coil and cyanoacrylate. No bleeding was observed after the operation. After discharge from the hospital, a telephone follow-up showed no further bleeding signs. CONCLUSION: Hemosuccus pancreaticus caused by gastroduodenal artery pseudoaneurysm associated with chronic pancreatitis is very rare. This diagnosis should be considered when upper gastrointestinal bleeding and abdominal pain are intermittent. Abdominal enhanced computed tomography and angiography are important for diagnosis and treatment.

Poorer prognosis for neuroendocrine carcinoma than signet ring cell cancer of the colon and rectum (CRC-NEC): a propensity score matching analysis of patients from the Surveillance, Epidemiology, and End Results (SEER) database.

PURPOSE: Colorectal neuroendocrine carcinomas (CRC-NECs) are rare, comprising < 1% of colorectal cancers. This study aimed to assess the incidence, clinicopathologic characteristics, prognostic factors, and treatment outcomes of CRC-NEC. METHODS: We analysed the Surveillance, Epidemiology, and End Results (SEER) database to identify patients from 20 to 74 years old diagnosed with CRC-NEC or common CRC (non-NEC) during 2004-2013. Log-rank testing was conducted to assess survival differences. A competing-risks regression model was used to adjust for covariate effects in the propensity score-matched (PSM) cohort, and adjusted hazard ratios (HRs) were calculated for the raw and PSM cohorts. RESULTS: We identified 67,484 patients (344 CRC-NEC and 67,140 non-NEC). Lymph node metastasis (LNM) was more common in CRC-NEC (75.29%, n = 259) than in non-NEC (51.53%, n = 34,600) (P < 0.001); 56.40% (n = 194) of CRC-NECs were located on the right side, while 18.31% (n = 63) were located on the left side, with a statistically significant difference in distribution (P < 0.001) compared to that in non-NEC CRC. Multivariate analysis indicated that a left-side location was an independent adverse prognostic factor for CRC-NEC (P = 0.043). CRC-NEC had the poorest cancer-specific survival (median CSS, 9.0 months) among assessed cancers, even poorer than that of signet ring cell cancer (median CSS, 24.0 months). However, both radical operation (P = 0.007) and chemotherapy (P = 0.008) were beneficial for CSS. CONCLUSION: NEC is a rare and extremely aggressive tumour with a poor prognosis. Right-side NEC has a better prognosis than left-side NEC. Early diagnosis, radical surgery, and chemotherapy are imperative for improving survival.

Low-complexity equalizer with a hybrid decision scheme for 50 Gb/s/λ PAM4-PON using a low-cost 10 G receiver.

In this Letter, we experimentally demonstrate a 50Gb/s/λ four-level pulse amplitude modulation-based passive optical network system with a 10 G class receiver. A memory polynomial equalizer (MPE) combined with a decision feedback equalizer (DFE) is applied to eliminate channel distortions in the system. To further improve the performance of the MPE-DFE, for the first time, to the best of our knowledge, a low-complexity hybrid decision scheme (HDS) is proposed, which consists of single-symbol decision (SSD) and multi-symbol decision (MSD). The SSD is exactly the conventional hard decision based on minimum Euclidean distance, whereas MSD is based on a simplified maximum likelihood detection principle with M-algorithm. In terms of complexity, MSD requires 19.1% more multiplications than SSD, but the symbol number of MSD only accounts for less than 20% of the total signal frame when the received optical power is greater than -27dBm. Experimental results show that the proposed MPE-DFE with HDS achieves a 0.7 dB and 1.3 dB sensitivity gain compared with conventional SSD, and up to 35.4 dB and 31.4 dB link power budget, regarding the forward error correction threshold of 10-2 and 10-3, respectively.