Wavelength dependency and photosensitizer effects in UV-LED photodegradation of iohexol

Iodinated X-ray contrast media (ICM) are ubiquitously present in water sources and challenging to eliminate using conventional processes, posing a significant risk to aquatic ecosystems. Ultraviolet light-emitting diodes (UV-LED) emerge as a promising technology for transforming micropollutants in water, boasting advantages such as diverse wavelengths, elimination of chemical additives, and no induction of microorganisms' resistance to disinfectants. The research reveals that iohexol (IOX) degradation escalates as UV wavelength decreases, attributed to enhanced photon utilization efficiency. Pseudo-first-order rate constants (kobs) were determined as 3.70, 2.60, 1.31 and 0.65 cm2 J-1 at UV-LED wavelengths of 255, 265, 275 and 285 nm, respectively. The optical properties of dissolved organic matter (DOM) and anions undeniably influence the UV-LED photolysis process through photon competition and the generation of reactive substances. The influence of Cl- on IOX degradation was insignificant at UV-LED 255, but it promoted IOX degradation at 265, 275 and 285 nm. IOX degradation was accelerated by ClO2-, NO3-and HA due to the formation of various reactive species. In the presence of NO3-, the kobs of IOX followed the order: 265 > 255 > 275 > 285 nm. Photosensitizers altered the spectral dependence of IOX, and the intermediate photoactivity products were detected using electron spin resonance. The transformation pathways of IOX were determined through density functional theory calculations and experiments. Disinfection by-products (DBPs) yields of IOX during UV-LED irradiation decreased as the wavelength increased: 255 > 265 > 275 > 285 nm. The cytotoxicity index value decreased as the UV-LED wavelength increased from 255 to 285 nm. These findings are crucial for selecting the most efficient wavelength for UV-LED degradation of ICM and will benefit future water purification design.

Enhanced 2-MIB degradation by UV-LED/chlorine process: reaction kinetics, wavelength dependence, influencing factors and degradation pathways

The efficient removal of 2-Methylisoborneol (2-MIB), a typical odour component, in water treatment plants (WTPs), poses a great challenge to conventional water treatment technology due to its chemical stability. In this study, the combination of ultraviolet light-emitting diode (UV-LED) and chlorine (UV-LED/chlorine) was exploited for 2-MIB removal, and the role of ultraviolet (UV) wavelength was investigated systematically. The results showed that UV or chlorination alone did not degrade 2-MIB effectively, and the UV/chlorine process could degrade 2-MIB efficiently, following the pseudo-first-order kinetic model. The 275 nm UV exhibited higher 2-MIB degradation efficiency in this UV-LED/chlorine system than 254 nm UV, 265 nm UV and 285 nm UV due to the highest mole adsorption coefficient and quantum yield of chlorine in 275 nm UV. ·OH and ·Cl produced in the 275 nm UV/chlorine system played major roles in 2-MIB degradation. HCO3- and Natural organic matter (NOM), prevalent in water, consumed ·OH and ·Cl, thus inhibiting the 2-MIB degradation by UV-LED/chlorine. In addition, NOM and 2-MIB could form a photonic competition effect. The degradation of 2-MIB by UV-LED/chlorine was done mainly through dehydration and demethylation, and odorous intermediates, such as camphor, were produced. 2-MIB was degraded through the α bond fracture and six-membered ring opening to form saturated or unsaturated hydrocarbons and aldehydes. Four DBPs, chloroform (CF), trichloroacetaldehyde (TCE), trichloroacetone (TCP) and dichloroacetone (DCP), were mainly generated, and CF was the most significant by-product.

[Recent research advances of angiogenesis in temporomandibular joint osteoarthritis]

Temporomandibular joint osteoarthritis (TMJOA) is a degenerative disease of temporomandibular joint, which has a high incidence and affects the quality of patients' life. While the pathogenesis of TMJOA remains unclear. It has been found that angiogenesis is involved in the development of TMJOA and it is closely related to the degradation of articular cartilage matrix, subchondral ossification, osteophyte formation and pain. This article reviews the recent advances in the study of angiogenesis in TMJOA, and provides a prospect for the treatment of TMJOA.

Comparison of four pre-oxidants coupled powdered activated carbon adsorption for odor compounds and algae removal: Kinetics, process optimization, and formation of disinfection byproducts

Pre-oxidation and powdered activate carbon (PAC) are usually used to remove algae and odorants in drinking waterworks. However, the influence of interaction between oxidants and PAC on the treatment performance are scarcely known. This study systematically investigated the combination schemes of four oxidants (KMnO4, NaClO, ClO2, and O3) and PAC on the inactivation of Microcystis aeruginosa cells and removal of four frequently detected odorants in raw water (diethyl disulfide (DEDS), 2,2'-oxybis(1chloropropane) (DCIP), 2-methylisoborneol (2-MIB) and geosmin (GSM)). O3 showed highest pseudo-first-order removal rate for all four compounds and NaClO exhibited highest inactivation rates for the cell viability and Chlorophyll a (Chl-a). The Freundlich model fitted well for the adsorption of DEDS and DCIP by PAC. When treated by combined oxidation/PAC, the removal ratio of algae cells and odorants were lower (at least 1.6 times) than the sum of removal ratios obtained in oxidation or PAC adsorption alone. Among these four oxidants, the highest synchronous control efficiency of odorants (52 %) and algae (66 %) was achieved by NaClO/PAC. Prolonging the dosage time interval promoted the removal rates. The pre-PAC/post-oxidation processes possessed comparable efficiency for the removal of odorants and algae cells comparing with pre-oxidation/post-PAC process, but significantly inhibited formation of disinfection byproducts (DBPs), especially for the formation of C-DBPs (for NaClO and ClO2), bromate (for O3) and chlorate/chlorite (for ClO2). This study could provide a better understanding of improving in-situ operation of the combined pre-treatments of oxidation and PAC for source water.

Insight into mixed chlorine/chloramines conversion and associated water quality variability in drinking water distribution systems

Mixed chlorine/chloramines are common in drinking water distribution systems (DWDSs); however, their transformation and impact on chemical and microbial characteristics are not well understood. We systematically investigated water quality parameters associated with mixed chlorine/chloramine species conversion in 192 samples (including raw, finished, and tap water) collected throughout the year in a city in East China. Various chlorine/chloramine species (free chlorine, monochloramine [NH₂Cl], dichloramine [NHCl₂], and organic chloramines [OC]) were detected in both chlorinated and chloraminated DWDSs. NHCl₂ + OC increased with transport distance along the pipeline network. The maximum proportion of NHCl₂ + OC in over total chlorine in tap water reached 66 % and 38 % from chlorinated and chloraminated DWDSs, respectively. Both free chlorine and NH₂Cl showed a rapid decay in the water pipe systems, but NHCl₂ and OC were more persistent. Correlations between chlorine/chloramine species and physicochemical parameters were established. Models for predicting the sum of chloroform/TCM, bromodichloromethane/BDCM, chlorodibromomethane/CBDM, and bromoform/TBM (THM₄) (R² = 0.56) and haloacetic acids (HAAs) (R² = 0.65) exhibited greater accuracy based on machine learning tuned with chlorine/chloramine species, particularly NHCl₂ + OC. The predominant bacterial communities in mixed chlorine/chloramine systems were those resistant to chlorine or chloramine such as proteobacteria. NH₂Cl was the most significant explanatory factor (28.1 %) for the variation in microbial community assemblage in chloraminated DWDSs. Although residual free chlorine and NHCl₂ + OC, accounted for a smaller proportion of chlorine species in chloraminated DWDSs, they played an essential role (12.4 % and 9.1 %, respectively) in the microbial community structure.

Degradation of odorous 2,4,6-trichloroanisole in chlorinated water by UV-LED/chlorination: kinetics and influence factors

2,4,6-Trichloroanisole (2,4,6-TCA) has aroused a special concern for their odor problem and potential threats. In this study, the degradation of 2,4,6-TCA by UV/chlorination with different UV sources was compared, including low-pressure mercury lamp (LPUV, 254 nm) and ultraviolet light-emitting diode (UV-LED, 275 and 285 nm). The maximum removal of 2,4,6-TCA can be achieved by 275-nm UV-LED/chlorination in neutral and alkaline conditions which was 80.0%. The reaction, kinetics, and water matrix parameters on 2,4,6-TCA degradation were also evaluated. During UV-LED (275 nm)/chlorination, 2,4,6-TCA degradation was mainly caused by direct UV photolysis and indirect hydroxyl radical (HO·) oxidation, while reactive chlorine radicals (RCSs) had a negligible contribution. The second-order rate constant between HO· and 2,4,6-TCA was determined as 3.1 × 10⁹ M^-1 s^-1. Increasing initial chlorine dosage and decreasing 2,4,6-TCA concentration or pH value significantly promoted 2,4,6-TCA degradation during UV/chlorination process. The presence of natural organic matter (NOM) and bicarbonate (HCO₃^-) can inhibit 2,4,6-TCA degradation, while chloride ion (Cl^-) had a negligible effect. The kinetic model for 2,4,6-TCA degradation was established and validated, and the degradation pathways were proposed based on the identified intermediates. Furthermore, UV-LED (275 nm)/chlorination also exhibited a promising effect on 2,4,6-TCA removal in real water, which can be used to control 2,4,6-TCA pollution and odor problems.

Continuous wave dual-wavelength Nd:YVO4 laser at 1342 and 1525 nm for generating a 714-nm emission

Continuous wave dual-wavelength lasers at 1342 and 1525 nm are developed by using separate Nd:YVO₄ and YVO₄ crystals to form compactly coupled cavities for fundamental and Raman waves, respectively. The design of the coupled cavity not only reduces the thermal lensing effect in the Nd:YVO₄ crystal, but also improves the stimulated Raman scattering (SRS) efficiency in the undoped YVO₄ crystal. In addition, the Raman crystal is coated to form a highly reflective mirror to minimize cavity losses. By using a plano-concave cavity with a pump power of 40 W, the output powers of the fundamental and Raman waves are 470 mW and 310 mW, respectively. Changed to a concave cavity, the output powers of fundamental and Raman waves are 220 mW and 510 mW, respectively. Basis on the dual-wavelength operation, the maximum output power at 714 nm can reach 2.0 W via the sum frequency generation. A light source at 714 nm can be used for laser spectroscopy of atomic and ionic radium isotopes.

Enhanced degradation of emerging contaminants by permanganate/quinone process: Case study with bisphenol A

Permanganate (Mn(VII)) is widely used as a mild oxidant in water treatment. However, the reaction rates of some emerging contaminants with Mn(VII) are extremely low. In this study, benzoquinone (BQ), a redox mediator with the important component in dissolved organic matter (DOM), enhanced the oxidation of bisphenol A (BPA) by Mn(VII) in a wide pH range of 4.0-10.0. The redox cycle of BQ would produce semiquinone radicals, which could act as ligands to stabilize the formed Mn(III) in the system to promote the oxidation of BPA. Notably, the presence of BQ might promote the formation of MnO₂. A novel mechanism was proposed that singlet oxygen (¹O₂), Mn(III)-ligands (Mn(III)-L) and in-situ formed MnO₂ were the main contributors to accelerate BPA degradation in the Mn(VII)/BQ system. Under acidic conditions, the in-situ formed MnO₂ involved in the redox reaction and part of the Mn(IV) was reduced to Mn(III), indicating that the electron transfer of BQ promoted the formation of active Mn species and enhanced the Mn(VII) oxidation performance. Semiquinone radicals generated by BQ transformation would couple with the hydrogen substitution products of BPA to inhibit BPA self-coupling and promote the ring-opening reactions of BPA. Mn(VII)/BQ had better effect in raw water than in pure water, indicating that the Mn(VII)/BQ system has high potential for practical application. This study provided insights into the role of DOM in enhancing the Mn(VII) oxidation in water treatment.

Enhanced formation of iodinated trihalomethanes in a mixed chlorine/chloramine system and attenuation by UV-activated process

Iodinated trihalomethanes (I-THMs) have drawn increasing concerns due to their higher toxicity than those of their chlorinated and brominated analogues. In this study, I-THM formation was firstly evaluated for three treatment scenarios - (i) chlorine alone, (ii) chloramine alone, and (iii) mixed chlorine/chloramine - in the presence and absence of UV irradiation for the iodide-containing humic acid solution or natural water. The results indicated that I-THM formation decreased in the order of mixed chlorination/chloramination > chloramination > > chlorination, which fitted the trend of toxicity evaluation results using Chinese hamster ovary cells. Conversely, total organic halide concentration decreased in the order of chlorination > > chloramination ≈ mixed chlorination/chloramination. Besides, I-THM formation can be efficiently controlled in a UV-activated mixed chlorine/chloramine system. Influencing factors including pH values and Br^-/I^- molar ratios were also systematically investigated in a mixed chlorine/chloramine system. Enhanced I-THM formation was observed with increasing pH values (6.0-8.0) and Br^-/I^- molar ratios (1: 1-10: 1). The results obtained in this study can provide new insights into the increasing risk of I-THM formation in a mixed chlorine/chloramine system and the effective control of I-THMs in the iodide-containing water using UV irradiation.

The formation, analysis, and control of chlor(am)ination-derived odor problems: A review

Odors and tastes have become universal problems related to drinking water quality. In addition to the typical odor problems caused by algae or microorganisms, the occurrence of odors derived from drinking water disinfection have attracted attention. The chlor(am)ination-derived odor substances have certain toxicity and odor-causing characteristics, and would enter the tap water through water distribution systems, directly affecting drinking water safety and customer experience. This study provided a comprehensive overview of the occurrence, detection, and control of odor substances derived from drinking water chlor(am)ination disinfection. The occurrence and formation mechanisms of several typical types of disinfection derived odor substances were summarized, including haloanisoles, N-chloroaldimines, iodotrihalomethanes, and halophenoles. They are mainly derived from specific precursors such as halophenols, anisoles, and amino acids species during the disinfection or distribution networks. In addition, the change of disinfectant during chlor(am)ination was also one of the causes of disinfection odors. Due to the extremely low odor threshold concentrations (OTCs) of these odor substances, the effective sample pre-enrichment for instrument identification and quantification are essential. The control strategies of odor problems mainly include adsorption, chemical oxidation, and combined processes such as ozonation and biological activated carbon processes (O₃/BAC) and ultraviolet-based advanced oxidation processes (UV-AOPs). Finally, the challenges and possible future research directions in this research field were discussed and proposed.

[Application of indocyanine green fluorescence imaging technique in evaluation of intestinal perfusion in totally laparoscopic left hemicolectomy]

Objective: To examine the safety and feasibility of using fusion indocyanine green fluorescence imaging (FIGFI) technique for intraoperative evaluation of colorectal perfusion in the totally laparoscopic left colectomy. Methods: A retrospective cohort study was conducted to collect the clinical data of 58 patients with left colon cancer who underwent totally laparoscopic surgery at the Colorectal Surgery Department, Cancer Hospital, Chinese Academy of Medical Sciences from October 2016 to December 2019. There were 39 males and 19 females, aging (57.0±10.1)years(range:28 to 75 years). According to whether the FIGFI was used during the operation, they were divided into 36 cases in the study group and 22 cases in the control group. The clinical pathological characteristics, operative and postoperative recovery of the two groups were compared by t test, χ² test, and Fisher exact test. Results: All the 58 patients underwent R0 resection with totally laparoscopic surgery. In the study group, due to poor bowel blood flow after cutting the mesentery (Sherwinter score = 1), 1 patient had to be expanded the resection range until the blood flow was rich(Sherwinter score≥3), and 1 patient in the control group had the complication of postoperative anastomotic leakage of grade A. Compared with the control group, the operation time in the study group was shorter ((156.3±43.5) minutes vs. (180.4±41.3) minutes, t=-2.083, P=0.042). However, there were no significant differences in the amount of blood loss, postoperative hospital stay, postoperative time of anal exhaust, length of bowel resection, number of lymph nodes dissected, and in the incidence of postoperative complications between the two groups. Median follow-up period was 23 months (range: 18 to 37 months). There were no long-term postoperative complications such as ischemic enteritis and anastomotic stenosis in both groups. Conclusions: The FIGFI is safe and feasible to assess the blood supply of intestinal segment and anastomosis during totally laparoscopic left hemicolectomy, and is easy to operate. It is expected to reduce the incidence of anastomotic leakage.

Forensic Application of Plant Evidence

Abstract

With the increasingly obvious role of plant evidence in case detection, forensic botany, which provides clues and evidence in crime scene investigation by using botanical research method has attracted growing attention. The common experimental techniques used in forensic botany are morphological examination, physical and chemical examination, molecular genetic examination, and so on. This paper briefly expounds the advantages and disadvantages of different test methods, summarizes the problems that need to be paid attention to in the application of forensic botany by arranging the related literatures and cases of forensic botanical research, in order to provide reference for scene investigation of cases.

[Short-term efficacy of preservation versus non-preservation of inferior mesenteric artery in laparoscopic-assisted radical resection for left hemicolon cancer]

Objective: In laparoscopic-assisted left hemicolectomy, previous studies have suggested that preserving the inferior mesenteric artery (IMA) may improve intestinal blood flow and reduce the incidence of anastomotic leakage. However, whether IMA should be retained is controversial currently. This study aims to investigate the short-term efficacy of the inferior mesenteric artery preservation (IMAP) and the inferior mesenteric artery resection (IMAR) on the laparoscopic-assisted radical resection of left hemicolon cancer. Methods: A retrospective cohort study was conducted to collect the clinical data of 195 patients with left colon cancer who underwent laparoscopic surgery in the Colorectal Surgery Department of Cancer Hospital of Chinese Academy of Medical Sciences from October 2012 to February 2019. After D3 radical resection for left semicolon cancer, they were divided into the IMAR group (91 cases), and the IMAP group (104 cases). In IMAR group, the left colon artery (LCA) and 1-2 branches of sigmoid artery (SA) were identified about 5 cm away from the root of the IMA, then the main IMA trunk was transected at the distal end. In IMAP group, the main trunk of IMA was dissected and the lymph nodes around IMA were cleaned. After the LCA and the first branch of SA (SA1) were separated, the LCA and SA1 were closed and cut off at the root. The intraoperative and postoperative data were compared between two groups, including the morbidity of complications within 30 days after operation, postoperative follow-up recovery, operation time, intraoperative blood loss, number of harvested lymph nodes, length of specimens, postoperative passage of gas and hospital stay. Results: The operation was successfully completed in all the cases without any death related to the operation. Compared with the IMAP group, the operation time was shorter [(161.8±48.0) minutes vs. (182.9±49.4) minutes, t=2.985, P=0.003], the intraoperative blood loss was less [(38.5±30.8) ml vs.(52.9±32.2) ml, t=2.088, P=0.038], the length of the resected bowel was longer [(19.2±6.0) cm vs.(17.2±5.4) cm, t=-2.447, P=0.015] in the IMAR group, whose differences were statistically significant (all P<0.05). There were no significant differences in the number of harvested lymph nodes, time of postoperative passage of gas and postoperative hospital stay between two groups (all P>0.05). There was no significant difference in overall morbidity of postoperative complications between the two group [6/91 (6.6%) vs. 7/104 (6.7%), χ(2)=0.001, P=0.969]. In the IMAR group, one case developed postoperative abdominal infection, two cases developed incision infection, one case developed lung infection, two cases developed intestinal obstruction, and no anastomotic bleeding occurred. In IMAP group, one case developed postoperative lung infection, one case developed incision infection, one case developed abdominal bleeding, two cases developed intestinal obstruction and two cases developed anastomotic bleeding. There was no anastomotic leakage in either group. All complications were treated by conservative treatment successfully. After a median follow-up of 12 (range 3-24) months, patients in the two groups had good intestinal blood supply after surgery, and there was no clear manifestation of congestive or ischemic enteritis under colonoscopy. Conclusion: Laparoscopic-assisted left hemicolectomy with IMA resection in patients with left hemicolon cancer provides better short-term efficacy safely and feasibly, including shorter operative time, less intraoperative bleeding and without increasing postoperative complications.

[Analysis of risk factors of severe postoperative complications in elderly patients with colorectal cancer aged over 80 years]

Objective: To investigate the risk factors of severe postoperative complications in elderly patients with colorectal cancer aged over 80 years old. Methods: A retrospective case-control study was conducted to collect and analyze the clinicopathological data of patients (≥80 years old) who underwent radical colorectal cancer surgery at department of Colorectal Surgery, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from January 2010 to December 2018. A total of 269 patients were included in the study, including 160 males and 109 females. The average age was 83 (80-94) years. Among them, the pathological TNM stage was 16 in stage I, 76 in stage II, 167 in stage III, and 10 in stage IV. According to Clavien-Dindo classification, the postoperative complications of grade III and above were defined as serious complications. To analyze the relationship between the patient's clinical data, such as general information, the surgeon's experience (whether to complete more than 500 radical colorectal cancer surgery), intraoperative conditions and the occurrence of severe complications. Univariate analysis was conducted with the chi-squared test. Multivariate logistic regression analysis was used for statistically significant variables in univariate analysis. Results: Of the 269 patients, 34 (12.6%) had severe complications after surgery. The incidence of postoperative complications ranged from high to low, respectively, for pulmonary infection (8/269,3.0%), intestinal obstruction (8/269, 3.0%) and anastomotic leakage (7/269, 2.6%). One patient died of pulmonary embolism and one patient died of multiple organ failure, with a perioperative mortality rate of 0.7% (2/269). On univariate analysis, the occurrence of severe postoperative complications was associated with age (χ(2)=8.181, P=0.004), American society of anesthesiologists grade (χ(2)=7.945, P=0.005), preoperative albumin level (χ(2)=9.088, P=0.003), operation experience (χ(2)=9.395, P=0.002). Multivariable logistic regression analysis showed that age ≥85 years old (OR=4.415, 95% CI: 1.702-11.453, P=0.080), preoperative albumin <35 g/L (OR=2.544, 95%CI: 1.083-5.974, P=0.032), and less-experieced group (OR=2.475, 95% CI:1.082-5.661, P=0.032) was independent risk factor for severe postoperative complications. The incidence of serious postoperative complications was similar in patients undergoing laparoscopy and laparotomy [10.1% (17/169) vs. 17.0% (17/100), χ(2)=2.741, P=0.098]. Conclusion: Adequate preoperative evaluation, appropriate perioperative nutritional support and experienced specialists are the key factors to ensure the successful perioperative period of elderly patients with colorectal cancer aged over 80 years old. In addition, more attention should be paid to the elderly patients aged ≥85 years.

[Short-term efficacy of totally laparoscopic left colon cancer radical resection with overlapped delta-shaped anastomosis technique]

Objective: To evaluate the safety, feasibility and short-term efficacy of totally laparoscopic left colectomy for left colon cancer by using overlapped delta-shaped anastomosis technique for digestive tract reconstruction. Methods: A retrospective cohort study was conducted to collect the clinical data of 86 patients with left colon cancer who underwent laparoscopic surgery in Cancer Hospital of Chinese Academy of Medical Sciences from October, 2017 to February, 2019. The patients were divided into totally laparoscopic left-sided colectomy (TLLC) (treatment group, n=25 cases) and laparoscopic-assisted left-sided colectomy (LALC) (control group, n=61 cases). The intraoperative and postoperative data were compared between the two groups. Results: There were no surgical-related deaths in both groups. All the patients in the TLLC group underwent laparoscopic resection, while one patient in the LALC group transfer to open surgery. The operation time in TLLC group and LALC group were (164.5±42.3) min and (171.0±43.1) min, respectively, without statistically significant difference (P=0.516). However, the intraoperative blood loss of patients in the TLLC group was (36.4±22.7) ml, which was significantly less than (52.9±32.2) ml in the LALC group (P=0.026). The anastomosis time in the TLLC group was (39.1±6.5) min, which was significantly longer than (24.9±5.4) min in the LALC group (P<0.001). Postoperative exhaust time in the TLLC group was (2.6±0.5) days, which was significantly shorter than (3.3±0.8) days in the LALC group (P<0.001). The incision length in the TLLC group was (4.2±2.2) cm, significantly shorter than (7.0±2.5) cm in the LALC group (P<0.001). The length of the resected bowel was (21.0±7.3) cm in the TLLC group, which was significantly longer than (17.5±5.4) cm in the LALC group (P=0.037). The length of hospital stay in the TLLC group was (6.2±1.9) days, which was significantly shorter than (7.9±1.5) days in the LALC group (P<0.001). The incidences of postoperative complications in the TLLC group and LALC group were 0 and 4.9% (3/61), respectively, without statistically significant (P=0.553). No anastomotic complications occurred in both groups. During the follow-up period, neither group of patients was hospitalized again, and no tumor metastasis or recurrence occurred. Conclusions: It is safe and feasible to apply the TLLC with overlapped delta-shaped anastomosis in patients with left colon cancer. It has better short-term effects such as shorter incisions, faster recovery, and shorter postoperative hospital stays, and is worthy of further promotion.

[Progress in diagnosis and treatment of rectal neuroendocrine neoplasms]

Neuroendocrine neoplasms (NENs) are relatively rare heterogeneous tumors that originate from peptidergic neurons and neuroendocrine cells and have been referred to as "carcinoids" in the past. Although this type of tumor had been previously considered to be indolent tumor with a low degree of malignancy, with the development of medicine and clinical study, researchers found that NENs had the potential to metastasize. They can occur in any part of the body where neuroendocrine cells are distributed and gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) are the most common type of NENs.Due to the improvement of techniques such as endoscopy and imaging, the incidence of rectal neuroendocrine tumors(R-NENs) and the number of related clinical researches have both increased significantly in recent years. Although researches in Chinese and foreign medical centers are mostly retrospective studies of small samples and the efficacies of different treatment methods are still under debating and lack of sufficient medical evidence to support, the diagnosis and treatment of this disease is gradually becoming standardized according to the proposal of corresponding guidelines. The recent advances in the epidemiology, diagnosis and treatment of rectal neuroendocrine neoplasms are reviewed in this paper.

[Health economic evidence for colorectal cancer screening programs in China: an update from 2009-2018]

Objective: This study was to systematically update the economic evaluation evidence of colorectal cancer screening in mainland China. Methods: Based on a systematic review published in 2015, we expanded the scope of retrieval database (PubMed, EMbase, The Cochrane Library, Web of Science, CNKI, Wanfang Data, VIP, CBM) and extended it to December 2018. Focusing on the evidence for nearly 10 years (2009-2018), basic characteristics and main results were extracted. Costs were discounted to 2017 using the consumer price index of medical and health care being provided to the residents, and the ratio of incremental cost-effectiveness ratio (ICER) to per capita GDP in corresponding years were calculated. Results: A total of 12 articles (8 new ones) were included, of which 9 were population-based (all cross-sectional studies) and 3 were model-based. Most of the initial screening age was 40 years (7 articles), and most of the frequency was once in a lifetime (11 articles). Technologies used for primary screening included: questionnaire assessment, immunological fecal occult blood test (iFOBT) and endoscopy. The most commonly used indicator was the cost per colorectal cancer detected, and the median (range) of the 20 screening schemes was 52 307 Chinese Yuan (12 967-3 769 801, n=20). The cost per adenoma detected was 9 220 Yuan (1 859-40 535, n=10). In 3 articles, the cost per life year saved (compared with noscreening) was mentioned and the ratio of ICER to GDP was 0.673 (-0.013-2.459, n=11), which was considered by WHO as "very cost-effective" ; The range of ratios overlapped greatly among different technologies and screening frequencies, but the initial age for screening seemed more cost-effective at the age of 50 years (0.002, -0.013-0.015, n=3), than at the 40 year-olds (0.781, 0.321-2.459, n=8). Conclusions: Results from the population-based studies showed that the cost per adenoma detected was only 1/6 of the cost per colorectal cancer detected, and limited ICER evidence suggested that screening for colorectal cancer was generally cost-effective in Chinese population. Despite the inconclusiveness of the optimal screening technology, the findings suggested that the initial screening might be more cost-effective at older age. No high-level evidence such as randomized controlled trial evaluation was found.

[Clinical analysis of laparoscopic remedial surgery for endoscopic lesions in early colorectal cancer]

Objective: To investigate the safety and feasibility of laparoscopic remedial surgery in patients who didn't reach the cure criterion of early colorectal cancer after endoscopic resection. Methods: The clinical and follow-up data of 12 patients who didn't reach the cure criterion of early colorectal cancer and then underwent endoscopic resection was collected. The clinicalpathological features and remedial indications were analyzed to evaluate the effects of laparoscopic remedial surgery. Results: The average number of lymph nodes in the lymph node dissection was 15 during remedial surgery, and 3 of them had lymph node metastasis. Among the 3 patients with residual cancer, two cases were poorly differentiated, 1 case was moderately differentiated, 1 case was positive for basal margin, and 1 case had vascular invasion. No lymph node metastasis occurred in the 9 patients who had no residual cancer. Among these, 8 cases were moderately differentiated, 1 case was poorly differentiated and 2 cases had positive basal margin. The average follow-up duration was 40 months and all 12 patients were in a state of survival at the last follow-up. During the follow-up of the 3 patients with residual cancer, 1 patient received adjuvant chemotherapy with unknown prognosis; 1 patient received postoperative adjuvant radiochemotherapy, and lung metastasis occurred; 1 patient did not receive any treatment after surgery and survived for 33 months. Conclusions: Laparoscopic remedial surgery is a safe and feasible remedy for patients who didn't reach the cure criterion of early colorectal cancer after endoscopic resection. However, the choice of remedial strategy for colorectal carcinoma needs further investigation for patients with no vascular invasion, high degree of differentiation, and negative basal margin.

[Association of malnutrition-inflammation-cardiovascular disease with cognitive deterioration in peritoneal dialysis patients]

OBJECTIVE

To investigate the relationship between malnutrition-inflammation-atherosclerosis (MIA) syndrome and deterioration of global and specific domains of cognitive function in peritoneal dialysis (PD) patients.

METHODS

This was a multi-center prospective cohort study. The PD patients who met the inclusion criteria were examined with general and specific cognitive function between March 2013 and November 2013. The patients were divided into MIA0, MIA1 and MIA2 groups, according to items of "Yes" for whether or not having cardiovascular disease, serum albumin≤35 g/L or high-sensitive C-reactive protein (hs-CRP) ≥3 mg/L. After 2 years, the patients maintained on PD would be repeatedly measured with cognitive function. The Chi-square test, One-way ANOVA, Kruskal-wallis H rank sum test were used to compare the differences of clinical characteristics, biochemical data, and global and specific cognitive function parameters among the three groups at baseline, and two years later, respectively. The Bonferroni method was applied to adjust the significance level for further comparison between each two different groups. The change of score in each cognitive parameter of global and specific domains was used as dependent variable. Age, gender, education level, depression index, body-mass index, diabetes mellitus, serum sodium levels and MIA (MIA0 was control, MIA1 and MIA2 as dummy variables) were all included in the multivariable linear regression models to analyze the risk factors of the deterioration of cognitive function. The analysis for each cognitive domain was adjusted for the baseline score of the corresponding cognitive parameter. All the analyses were performed using SPSS for Windows, software version 25.0 (SPSS Inc., Chicago, IL).

RESULTS

Over two-year follow up, the prevalence of cognitive impairment increased from 20.0% to 24.7%, absolute decrease of 3MS scores were more significantly decreased in MIA2 (-3.9±12.0 vs. 1.1±6.7, P<0.01) and MIA1 group (-2.3±11.8 vs. 1.1±6.7, P<0.05) than those in MIA0 group respectively. Specific cognitive functions, included executive function (trail-making tests A and B, P=0.401, P=0.176), immediate memory (P=0.437), delayed memory (P=0.104), visuospatial skill (P=0.496), and language ability (P=0.171) remained unchanged. Advanced age, lower education, diabetes mellitus and depression were all correlated with the deterioration of one or more cognitive domains, and the patients having one item of MIA syndrome were prone to develop the deterioration of 3MS (P=0.022). Furthermore, the patients having two or more items of MIA syndrome were more likely to develop the deterioration of not only 3MS (P <0.001), but also delayed memory, visuospatial skill, and language ability (P=0.002, P=0.007, P=0.004, respectively).

CONCLUSION

Patients with one item or above of MIA syndrome were at high-risk for the deterioration of global cognitive function. The more MIA syndrome items there were, the more specific cognitive domains deteriorated.

[Compliance rate of screening colonoscopy and its associated factors among high-risk populations of colorectal cancer in urban China]

Objective: To evaluate the compliance rate of screening colonoscopy and associated factors in high-risk populations of colorectal cancer (CRC) in urban China. Methods: CRC screening data from the Program of Cancer Screening in Urban China conducted in 12 provinces in 2012-2014 was used in the present study. All 97 445 participants were asked to take epidemiological questionnaire survey to evaluate their cancer risk. Participants who were evaluated as "high risk for CRC" were recommended to receive colonoscopy at designated hospitals. Chi-square tests were used to compare the differences of participation rates between groups. Multivariate logistic regression models were applied to explore the potential factors associated withthe compliance rate of screening colonoscopy. Results: Overall, 97 445 participants of CRC high-risk were included in this analysis, and 14 949 of them took screening colonoscopy, yielding a participation rate of 15.3%. The participation rate varied greatly across provinces, ranging from 25.2% (2 785/11 071) in Heilongjiang to 9.7% (1 698/17 515) in Liaoning. Moreover, the participation rate in 2013-2014 was significantly higher than that in 2012-2013 (17.1%(9 766/57 280) vs 12.9% (5 183/40 165), χ(2)=57.67, P<0.001) . The multivariate logistic regression analyses showed that: compared with individuals of 40-49 years old, individuals of 50-59 or 60-69 years old were more willing to accept screening colonoscopy, with OR of 1.17 (95% CI: 1.12-1.22) and 1.13 (95% CI: 1.08-1.19), respectively; compared with uneducated individuals, individuals with good educational background of equivalent to high school or higher (OR=1.29, 95% CI:1.10-1.50) were more willing to accept screening colonoscopy; compared with individuals who never took fecal occult blood tests (FOBT) before, individuals with previous positive FOBT results (OR=1.40, 95% CI:1.31-1.50) were more willing to accept screening colonoscopy; compared with individuals with no inflammatory bowel diseases (IBD), individuals with IBD (OR=1.63, 95%CI:1.56-1.69) were more willing to accept screening colonoscopy; Compared with individuals without polyp history, individuals having history of previous polyp detection (OR=1.43, 95% CI:1.37-1.50) were more willing to accept screening colonoscopy; compared to individuals with no family history of CRC, individuals with history of CRC (OR=1.60, 95% CI:1.53-1.66) were more willing to accept screening colonoscopy. Conclusion: The overall participation rate of screening colonoscopy among high-risk population of CRC in the 12 participating sites was 15.3%. The study findings indicated that age, education level, history of past fecal occult blood test, IBD, history of polyp, family history of CRC were associated with the compliance rate of colonoscopy in this population-based CRC screening program.

Ultrastructural and Cytochemical Properties of Peripheral Blood Cells of Piebald Naked Carp (Gymnocypris eckloni)

The ultrastructural and cytochemical properties of peripheral blood cells of Gymnocypris eckloni were investigated by transmission electron microscopy and a range of cytochemical techniques to provide clear insight into the structure and function of blood cells from this fish. Ultrastructurally, erythrocytes, leucocytes (neutrophils, eosinophils, lymphocytes, monocytes), thrombocytes and plasma cells were identified in the peripheral blood of G. eckloni. The most special ultrastructural characteristics of blood cells in this fish were that neutrophils exhibited only one type of cytoplasmic granules containing an eccentric, spherical or oval electron-dense core, and eosinophils presented two types of granules with non-uniform electronic density and without crystalloids in their cytoplasm. Neutrophils, eosinophils, lymphocytes, monocytes and thrombocytes were positive for periodic acid-Schiff and α-naphthyl acetate esterase staining. Intense peroxidase positive staining was observed in neutrophils and monocytes, but not in eosinophils, lymphocytes and thrombocytes. Neutrophils, eosinophils and monocytes were stained positively for acid phosphatase, whereas lymphocytes and thrombocytes did not stain. Leucocytes and thrombocytes were negative for alkaline phosphatase and Sudan black B staining. Erythrocytes were negative for all cytochemical staining. The cytochemical and ultrastructural features of peripheral blood cells of G. eckloni were similar to those of other fish species. However, some important differences were identified in G. eckloni.

Immunogenicity of a recombinant fusion protein of tandem repeat epitopes of foot-and-mouth disease virus type Asia 1 for guinea pigs

In this study, the sequences of capsid protein VPI regions of YNAs1.1 and YNAs1.2 isolates of foot-and-mouth disease virus (FMDV) were analyzed and a peptide containing amino acids (aa) 133-158 of VP1 and aa 20-34 of VP4 of FMDV type Asia I was assumed to contain B and T cell epitopes, because it is hypervariable and includes a cell attachment site RGD located in the G-H loop. The DNA fragments encoding aa 133-158 of VP1 and aa 20-34 of VP4 of FMDV type Asia 1 were chemically synthesized and ligated into a tandem repeat of aa 133-158-20 approximately 34-133-158. In order to enhance its immunogenicity, the tandem repeat was inserted downstream of the beta-galactosidase gene in the expression vector pWR590. This insertion yielded a recombinant expression vector pAS1 encoding the fusion protein. The latter reacted with sera from FMDV type Asia 1-infected animals in vitro and elicited high levels of neutralizing antibodies in guinea pigs. The T cell proliferation in immunized animals increased following stimulation with the fusion protein. It is reported for the first time that a recombinant fusion protein vaccine was produced using B and T cell epitopes of FMDV type Asia 1 and that this fusion protein was immunogenic. The fusion protein reported here can serve as a candidate of fusion epitopes for design of a vaccine against FMDV type Asia 1.

A recombinant fusion protein and DNA vaccines against foot-and-mouth disease virus type Asia 1 infection in guinea pigs

On the basis of amino acid (aa) sequence of the tandem repeat 133-158-20-34-133-158 which consisted of aa 133-158 of VP1 and aa 20-34 of VP4 of Foot-and-mouth disease virus (FMDV) type Asia 1 a recombinant prokaryotic expression vector pAS1-P encoding a fusion protein and eukaryotic expression vectors pAS1-E and pAS1-EdeltaCpG-ODN representing DNA vaccines were constructed. Guinea pigs immunized with these vaccines showed both neutralizing antibody and T cell proliferation responses. FMDV challenge tests for the first time showed that the recombinant fusion protein and pAS1-E and pAS1-EdeltaCpG-ODN vaccines protected 86%, 60% and 43% of guinea pigs from FMDV type Asia1 challenge, respectively. The results also indicated that the immune response of animals treated with the vector pAS1-E containing an oligodeoxynucleotide (ODN), which consisted of immunostimulatory cytosine-phosphate-guanosine (CpG) motifs, was augmented by CpG ODN.

[Study on the DNA vaccine against foot-and-mouth disease virus using the heavy chain constant region of swine IgG as the carrier for peptide epitopes]

The peptide of amino acids 141-160 of VP1 protein of foot-and-mouth disease virus (FMDV) is a major B cell epitope and the peptide of amino acids 21-40 is an important T cell epitope. In this study, the DNA fragments of 141-160 and 21-40 peptide epitopes of a strain of type O FMDV was chemically synthesized and arranged into a tandem repeat 141-160 (20AA)-21-40 (20AA)-141-160 (20AA). This tandem sequence was fused to the 3' end of the heavy chain constant region gene of swine immunoglobulin G and was then cloned into mammalian expression vector pCDM8 to form a recombinant plasmid pCDM8FZ3. After pCDM8FZ3 was inoculated intramuscularly into guinea pigs, it elicited a neutralizing antibody response and a specific spleen T cell proliferative response, and 66% of the vaccinated animals were protected from viral challenge. Our study indicated that the heavy chain constant region of swine IgG can act as the carrier protein for FMDV peptide epitopes, and pC-DM8FZ3 is a potential DNA vaccine candidate to prevent FMDV infection.

Plasmids encoding foot-and-mouth disease virus VP1 epitopes elicited immune responses in mice and swine and protected swine against viral infection

VP1 is a capsid protein of foot-and-mouth disease virus (FMDV) and contains epitopes of the virus. Plasmids encoding two VP1 epitopes (amino acid residues 141-160 and 200-213) and a host-self immunoglobulin molecule were constructed to produce a new type of FMD DNA vaccine. Two plasmids, namely, pCEIM and pCEIS, containing mouse immunoglobulin (IgG) or swine IgG were subjected to immunogenicity testing in mice and swine, respectively. In mice administrated pCEIM in the abdomen using a genegun, both FMDV-specific T-cell proliferation and neutralizing antibodies were detected. In swine immunized with pCEIS at the back of the ear, immune responses were achieved after the second administration. Swine showed a T-cell proliferative response with a stimulation index (SI) of up to 8.1 and a neutralizing antibody response that was able to protect suckling mice from 10(2) LD(50) (lethal dose 50) FMDV challenge. To compare the immunogenicity of the DNA-based vaccine candidate, versus the protein-based vaccine candidates, a second group of swine was immunized with the protein F1-scIgG, which was encoded by the plasmid pCEIS. Injection with F1-scIgG elicited a T-cell proliferative response of SI < 1.7 and a neutralizing antibody response that protected suckling mice from up to 10(5) LD(50) FMDV challenge. In the challenge test, three of three swine immunized with pCEIS were fully protected from FMDV challenge.

An immunoglobulin G based chimeric protein induced foot-and-mouth disease specific immune response in swine

Epitopes containing the residues 141aa-160aa and 200aa-213aa from foot-and-mouth disease (FMD) serotype O1K HK type FMDV VP1 were joined to a swine immunoglobulin G single heavy chain constant region (scIgG), creating a novel chimeric protein, named F1-scIgG. In this study, inoculation with F1-scIgG induced both FMD virus-neutralizing antibody response and T cell response in swine. Antisera from these F1-scIgG-inoculated swine protected suckling mice against 1000 lethal dose 50 (1000LD(50)) FMD challenge. F1-scIgG-inoculated swine were also fully protected against 50LD(50) FMD virus challenge. The present study demonstrates the clear potential for viral epitopes linked with self-Ig in novel FMD vaccine design.

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application

OBJECTIVES

The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans.

BACKGROUND

Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation.

METHODS

Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests.

RESULTS

The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing.

CONCLUSIONS

These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.

[Modulation of T-cell-mediated immune responses by trichosanthin via antigen processing and presentation]

It has been shown in our previous study that the lymphoproliferation to allo- or soluble antigens could be inhibited when T cells were cocultured with antigen presenting cells (APCs) pulsed with Trichosanthin (Tk), a plant protein purified from a Chinese medicinal herb Trichosanthes kirilowii Maximovich. In this paper, data are presented dealing with the mechanism by which the Tk functioned as a down modulator. APCs of human peripheral blood were first treated with one of inhibitors of antigen processing (chloroquine, leupeptin or cycloheximide), followed by pulsed with Tk, and then added into a T cell culture with stimulators PMA and A 23187. The suppression of lymphoproliferation was observed to be obviously diminished or totally disappeared. In contrast, when CyA was used to replace the Tk for pulse-treatment of APCs that had received the same pretreatment with the inhibitors, no significant change was detected for the suppression, suggesting that the Tk might use a different pathway to induce hyporeactivity and that the pathway was concerned in APC's function of antigen presentation. This view obtained support from our immuno-histochemical examination of the Tk-pulsed APCs. By preparing colloidal gold-labelled Tk (Tk-G particle), we were able to show that the Tk-G, when incubated with APCs and T cells at 37 degrees C for two hours and washed, was visualized under the electronic microscope to be bound to APCs', instead of T cells', membrane surface and internalized cells' into endosomes. And then the Tk-G particles were further identified within lysosomes. In this way, the Tk molecules were subjected to be processed as an external antigen and might be presented to T cells to activate certain T subsets that in turn mediated the immunosuppression. This course was capable of, as expected, being interrupted by antigen processing inhibitor, especially by chloroquine.

Survey of 160 centenarians in Shanghai

One hundred and sixty centenarians were discovered and followed up for 7 years (1982-88) in Shanghai. The proportion of centenarians in the population was non-significantly greater in the urban than in the rural area and centenarians were in general increasing in both areas over the years. The factors promoting longevity were good medical care and benevolent attention from family members. Autopsy was performed in eight centenarians revealing the main causes of death as pneumonia and cancer.

Influence of operation under epidural anesthesia on peripheral t lymphocyte subsets

This paper reports the variation of peripheral T lymphocyte subsets in patients before and after operation under epidural anesthesia using OKT monoclonal antibodies (McAb). The results show that TH and TS after anesthesia and during surgery were lower than before anesthesia and in normal controls (P less than 0.05). The ratio of TH/TS after anesthesia and during operation were lower than before anesthesia (P less than 0.05), but there was no significant difference with normal controls (P greater than 0.05). Therefore, we consider that the decrease in TH cells was one of the reasons for decrease in patient immune function during anesthesia and surgery. Five to seven days after surgery, patient TH cell levels tended to normalize. This showed that this abnormality was transient and reversible. The results also indicated that emphasising prevention of infection in post-operational case, should be done during the first 5-7 days after surgery.

[Changes of the release of atrial natriuretic factor (ANF) and its gene transcription in morphine tolerance rat atrium]

Specific radioimmunoassay and molecular hybridization technique were used in the present work. Compared with the control rats, we found for the first time a significant decrease of ANF in plasma and a marked increase of ANF in atria in morphine tolerant rats. Simultaneously a raised level of ANF messenger RNA in morphine tolerant rat atria was observed. It is suggested that the biosynthesis and storage of ANF in atria be increased and its release from atria decreased in morphine tolerant rats.

Dissection of the r-determinant of the plasmid R100.1: the sequence at the extremities of Tn21

We have sequenced the extremities of the transposon Tn21, isolated from the r-determinant of the multiple antibiotic resistance plasmid R100.1, and show that it is a member of the Tn3 family of elements.