[Changes in protein requirements of elderly people over 5 years assessed using the indicator amino acid oxidation method].

OBJECTIVE: To evaluate the changes in protein requirements of the elderly during the past five years. METHODS: Based on the previous study of protein requirements of 14 elderly in 2017, 4 of these elderly(70-80 y) were included as study participants and protein requirements were re-evaluated using the indicator amino acid oxidation method. There were seven protein levels: 0.1, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 g/(kg·d). Maintenance diets were given for the first two days of each protein level. A stable isotope study was conducted on the day 3, using L-~(13)C-phenylalanine as an indicator on the basis of an amino acid rationed diet, which was orally ingested into the body along with the amino acid rationed diet, and breath and urine samples were collected when the metabolism of L-~(13)C-phenylalanine reached steady state in the body. By measuring the kinetic parameters of labeled amino acids in the samples, a nonlinear mixed-effects model was constructed for the protein intake to be tested and the oxidation rate of labeled amino acids. The mean protein requirement of the study population was determined by the protein intake corresponding to the inflection point of the curve. RESULTS: Based on the production rate of ~(13)CO_2 in exhaled breath of four elderly people at different protein levels, the mean protein requirement was 1.05(95%CI 0.51-1.60) g/(kg·d). The protein recommended nutrient intake was 1.31(95%CI 0.64-2.00) g/(kg·d) was estimated by applying the coefficient of variation of the mean protein requirement to derive the recommended nutrient intake. CONCLUSION: Protein requirements in the elderly have increased over a five-year period and sarcopenia may be the main cause of increased protein requirements.

The effect of indoor air filtration on biomarkers of inflammation and oxidative stress: a review and meta-analysis of randomized controlled trials.

Improvement of indoor air quality is beneficial for human health. However, previous studies have not reached consistent conclusions regarding the effects of indoor air filtration on inflammation and oxidative stress. This study aims to determine the relationship between indoor air filtration and inflammation and oxidative stress biomarkers. We conducted an electronic search that evaluated the association of indoor air filtration with biomarkers of inflammation and oxidative stress in five databases (PubMed, Cochrane Library, EMBASE, Web of Science, and Scopus) from the beginning to April 23, 2023. Outcomes included the following markers: interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), malondialdehyde (MDA), 8-hydroxy-2deoxyguanosine (8-OHdG), and 8-iso-prostaglandinF2α (8-isoPGF2α). We extracted data from the included studies according to the system evaluation and the preferred reporting item for meta-analysis (PRISMA) guidelines and used the Cochrane risk of bias tool to assess bias risk. Our meta-analysis included 15 studies with 678 participants to assess the combined effect size. The meta-analysis demonstrated that indoor air filtration could have a marked reduction in IL-6 (SMD: -0.275, 95% CI: -0.545 to -0.005, p = 0.046) but had no significant effect on other markers of inflammation or oxidative stress. Subgroup analysis results demonstrated a significant reduction in 8-OHdG levels in the subgroup with < 1 day of duration (SMD: -0.916, 95% CI: -1.513 to -0.320; p = 0.003) and using filtrete air filter (SMD: -5.530, 95% CI: -5.962 to -5.099; p < 0.001). Our meta-analysis results depicted that indoor air filtration can significantly reduce levels of inflammation and oxidative stress markers. Considering the adverse effects of air pollution on human health, our study provides powerful evidence for applying indoor air filtration to heavy atmospheric pollution.

Reevaluation of the protein requirement in Chinese elderly adults without sarcopenia with the indicator amino acid oxidation technique.

It is now generally believed that elderly may have slightly higher dietary protein requirements than those of the young-middle-aged adults. We have previously conducted related studies by the indicator amino acid oxidation (IAAO) technique, but more research data are needed to revise the protein requirements of the elderly. The main objective was to reevaluate the dietary protein requirements of healthy Chinese adults (65-80 years) without sarcopenia by using the IAAO technique. Nine healthy adult men and seven healthy adult women participated in the study, with protein intakes ranging from 0·1 to 1·8 g/(kg·d). Diets that delivered energy at a 1·5 resting energy expenditure were isocaloric. The amounts of phenylalanine and tyrosine needed to remain constant for each protein dosage. By applying a nonlinear mixed-effects model analysis on the F13CO2 data, which revealed a breakpoint in F13CO2 in response to graded protein intakes, the mean protein requirement was calculated. The mean estimated average requirement (EAR) for healthy elderly Chinese adults without sarcopenia was determined to be 0·94 g/(kg·d). The protein recommended nutrient intake (RNI) determined using various derivation approaches ranged from 1·13 to 1·36 g/(kg·d). The EAR for Chinese adults without sarcopenia aged 65-80 years in this study is 6·8 % higher than the current recommended EAR (0·88 g/(kg·d)). The RNI derived using various derivation approaches are all greater than the current RNI (0·98 g/(kg·d)). This trial was registered with the Chinese clinical trial registry as ChiCTR2200061382.

[Change of drinking water quality in Shijiazhuang South-to-North Water Diversion area from 2014 to 2021].

OBJECTIVE: To analyze the change of drinking water quality in the receiving area of Shijiazhuang South-to-North Water Transfer Project. METHODS: 2029 monitoring data of drinking water in the receiving areas of the South-to-North Water Transfer Project in Shijiazhuang from 2014 to 2021 were collected and collated according to the Sanitary Standard for Drinking Water(GB 5749-2006). Off-work water and pipe water before and after the total coliform group of South-to-North Water Transfer Project, heat-resistant coliform bacteria, escherichia coli, the total number of colonies, arsenic, cadmium, chromium, lead, mercury, nitrate, fluoride, selenium, cyanide, chloroform, carbon tetrachloride, chromaticity and turbidity, odor and taste, visible to the naked eye, pH, aluminum, iron, manganese, copper, zinc, chloride, sulfate, total soluble solids, total hardness, oxygen consumption, volatile phenols, anionic synthetic detergent, ammonia nitrogen, residual chlorine and chlorine dioxide were evaluated and compared. χ~2 test was used to compare the qualified rate, Mann-Whitney rank sum test was used to compare the test values of each index, and simple superposition comprehensive water environmental quality index method was used to evaluate the water quality comprehensively. RESULTS: Before the South-to-North Water Transfer Project, the total qualified rate of drinking water was 84.21%, that of factory water was 81.29%, and that of end water was 85.97%. The total qualified rate of drinking water after the South-to-North Water Transfer Project was 98.72%, that of factory water was 98.89%, and that of end water was 98.66%. The total qualified rate of water quality, the qualified rate of factory water and the qualified rate of end water after the South-to-North water transfer were higher than those before the transfer(P<0.05). The qualified rates of microbial indexes and total hardness of ex-factory water before the South-to-North Water Transfer Project were 94.37% and 89.94%, and those of microbial indexes and total hardness of end water were 94.32% and 93.35%, respectively. After the South-to-North Water Transfer, the qualified rates of microbial indexes and total hardness of the ex-factory water were 100.00% and 98.90%, and the qualified rates of microbial indexes and total hardness of the end water were 100.00% and 99.24%, respectively. After the South-to-North water transfer, the qualified rate of microbial indexes and total hardness of factory water and peripheral water were higher than those before the transfer(P<0.05). After the South-to-North Water Transfer, the M of total coliform group, total colony number, total hardness, fluoride, nitrate nitrogen, chloride, sulfate and dissolved total solids were lower than those before water transfer(For example, the median number of colonies and total hardness of factory water before the South-to-North Water Transfer were 20.00 CFU/100 mL and 248.00 mg/L, respectively. After the South-to-North Water Transfer, the median number of colonies and total hardness were 1.00 CFU/100 mL and 129.00 mg/L, respectively), while the M of trichloromethane, aluminum, pH and oxygen consumption were higher than those before water transfer(For example, the median of trichloromethane and aluminum before the South-to-North Water Transfer is 0.04×10~(-2) and 0.04×10~(-1) mg/L, respectively. After the South-to-North Water Transfer, the median of chloroform and aluminum were 0.06×10~(-2) and 0.25×10~(-1) mg/L, respectively)(P<0.05). The median WQI of comprehensive water environmental quality index before and after the South-to-North Water Transfer was 4.58 and 2.37(P<0.05), respectively. CONCLUSION: The introduction of the South-to-North Water Transfer has significantly improved the quality of drinking water in Shijiazhuang city. Microbial contamination and total hardness exceedance have been greatly improved.

The protective effects of procyanidin supplementation on PM2.5-induced acute cardiac injury in rats.

OBJECTIVE: Numerous epidemiological and experimental studies have indicated that ambient fine particulate matter (PM2.5) exposure can lead to myocardial injury by inhibiting oxidative stress and apoptosis. The effects of procyanidin (PC) on PM2.5-induced cardiovascular diseases (CVDs) are still unknown. The purpose of this study was to explore the protective effect of PC supplementation on PM2.5-induced oxidative stress and cardiomyocyte apoptosis in rats. METHOD: Rats were treated by gavage with three different PC concentrations (50, 100 and 200 mg/kg) for 21 days prior to exposure to 10 mg/kg PM2.5 suspension liquid by intratracheal instillation every other day for three times. We determined myocardial reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the myocardium were measured. The expression levels of apoptosis-related proteins, including p-Akt/Akt, Bcl-2, caspase-3 and Bax, were determined. In addition, histopathological examination was used to evaluate cardiac injury. RESULTS: PM2.5 exposure noticeably elevated the contents of MDA and ROS and decreased the activities of GSH-Px and SOD. PM2.5 exposure inhibited Bcl-2 expression and up-regulated caspase-3 and Bax expression in the myocardium of rats. The anti-apoptosis-related index p-Akt/Akt was reduced. Moreover, pretreatment with PC could attenuate these PM2.5-induced changes. However, remarkable differences in the protective effect of different PC doses did not exist. CONCLUSIONS: The results indicated that PC supplementation could effectively attenuate the oxidative stress and apoptosis induced by PM2.5 in rat myocardial tissue.

A Time-Series Analysis on the Association Between Fine Particulate Matter and Daily Mortality - Shijiazhuang City, Hebei Province, China, 2015-2020.

Introduction: Shijiazhuang is one of the most polluted cities in China, but few studies have investigated the acute impact of fine particulate matter (PM2.5) on mortality in this city. We assessed associations between PM2.5 and cause-specific mortality during 2015 to 2020. Methods: We obtained air quality data from Shijiazhuang Ecology and Environment Bureau, meteorological data from Shijiazhuang Meteorological Bureau, and mortality data from Shijiazhuang CDC's Cause of Death Reporting System for our analyses. We used a quasi-Poisson regression generalized additive model to assess excess risk of death for a single time-lag and for moving average time-lags of 0-7 days, stratifying by year, sex, age, and education. Results: There were 76,859 non-accidental deaths recorded in Shijiazhuang during the study period. The daily concentration of PM2.5 ranged from 6.3 µg/m3 to 625.3 µg/m3, and the annual mean concentration was 77.6 µg/m3. Regression analysis showed that an increment of PM2.5 of 10 µg/m3 in a two-day average concentration (lag01) was associated with 0.47% [95% Confidence Interval (CI): 0.24%, 0.70%], 0.49% (95% CI: 0.19%, 0.79%), and 0.72% (95% CI: 0.22%, 1.23%) increases in non-accidental deaths, cardiovascular disease deaths, and respiratory disease deaths, respectively. With reduction of PM2.5 concentration, impact of PM2.5 on respiratory disease deaths decreased, but the impact of PM2.5 on total non-accidental deaths and circulatory disease deaths did not change significantly. Conclusion: Although PM2.5 has been greatly reduced in recent years, PM2.5 pollution is still serious in Shijiazhuang. PM2.5 was significantly associated with non-accidental death, cardiovascular disease death, and respiratory disease death. As PM2.5 concentrations decreased, risk of death from respiratory diseases also decreased.

App based education programme to reduce salt intake (AppSalt) in schoolchildren and their families in China: parallel, cluster randomised controlled trial.

OBJECTIVE: To determine whether a smartphone application based education programme can lower salt intake in schoolchildren and their families. DESIGN: Parallel, cluster randomised controlled trial, with schools randomly assigned to either intervention or control group (1:1). SETTING: 54 primary schools from three provinces in northern, central, and southern China, from 15 September 2018 to 27 December 2019. PARTICIPANTS: 592 children (308 (52.0%) boys; mean age 8.58 (standard deviation 0.41) years) in grade 3 of primary school (about 11 children per school) and 1184 adult family members (551 (46.5%) men; mean age 45.80 (12.87) years). INTERVENTION: Children in the intervention group were taught, with support of the app, about salt reduction and assigned homework to encourage their families to participate in activities to reduce salt consumption. MAIN OUTCOME MEASURES: Primary outcome was the difference in salt intake change (measured by 24 hour urinary sodium excretion) at 12 month follow-up, between the intervention and control groups. RESULTS: After baseline assessment, 297 children and 594 adult family members (from 27 schools) were allocated to the intervention group, and 295 children and 590 adult family members (from 27 schools) were allocated to the control group. During the trial, 27 (4.6%) children and 112 (9.5%) adults were lost to follow-up, owing to children having moved to another school or adults unable to attend follow-up assessments. The remaining 287 children and 546 adults (from 27 schools) in the intervention group and 278 children and 526 adults (from 27 schools) in the control group completed the 12 month follow-up assessment. Mean salt intake at baseline was 5.5 g/day (standard deviation 1.9) in children and 10.0 g/day (3.5) in adults in the intervention group, and 5.6 g/day (2.1) in children and 10.0 g/day (3.6) in adults in the control group. During the study, salt intake of the children increased in both intervention and control groups but to a lesser extent in the intervention group (mean effect of intervention after adjusting for confounding factors -0.25 g/day, 95% confidence interval -0.61 to 0.12, P=0.18). In adults, salt intake decreased in both intervention and control groups but to a greater extent in the intervention group (mean effect -0.82 g/day, -1.24 to -0.40, P<0.001). The mean effect on systolic blood pressure was -0.76 mm Hg (-2.37 to 0.86, P=0.36) in children and -1.64 mm Hg (-3.01 to -0.27, P=0.02) in adults. CONCLUSIONS: The app based education programme delivered through primary school, using a child-to-parent approach, was effective in lowering salt intake and systolic blood pressure in adults, but the effects were not significant in children. Although this novel approach could potentially be scaled up to larger populations, the programme needs further strengthening to reduce salt intake across the whole population, including schoolchildren. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1800017553.

Sesamin attenuates PM2.5-induced cardiovascular injury by inhibiting ferroptosis in rats.

Objective: This study aimed to elucidate the pharmacological effects of sesamin (Ses) and its mechanism of action towards PM2.5-induced cardiovascular injuries. Method: Forty Sprague Dawley (SD) rats were randomly divided into five groups: a saline control group; a PM2.5 exposure group; and low-, middle-, and high-dose Ses pretreatment groups. The SD rats were pretreated with different concentrations of Ses for 21 days. Afterward, the rats were exposed to ambient PM2.5 by intratracheal instillation every other day for a total of three times. The levels of inflammatory markers, including tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1ß), and interleukin-6 (IL-6), and indicators related to oxidative responses, such as total superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA), were measured in the blood and heart. The expression of ferroptosis-related proteins in heart tissues was determined via western blot and immunohistochemistry. Results: Ses pretreatment substantially ameliorated cardiovascular injuries in rats as evidenced by the decrease in the pathological score and collagen area. The decreased levels of SOD, GSH, and GSH-Px in the heart and serum were inhibited by Ses. In addition, Ses not only notably increased the activity of antioxidant enzymes but also reduced the levels of MDA, CK, LDH, CK-MB, IL-6, TNF-α, IL-1ß, and IL-6. Furthermore, Ses pretreatment upregulated the expression levels of GPX4, SLC7A11, TFRC, and FPN1 and inhibited the expression levels of FTH1 and FTL. Conclusion: Ses pretreatment could ameliorate PM2.5-induced cardiovascular injuries perhaps by inhibiting ferroptosis. Therefore, Ses pretreatment may be a novel strategy for the prevention and treatment of PM2.5-induced cardiovascular injury.

Development of alveolar-capillary-exchange (ACE) chip and its application for assessment of PM2.5-induced toxicity.

Although standard two-dimensional (2D) cell culture is an effective tool for cell studies, monolayer cultivation can yield imperfect or misleading information about numerous biological functions. In this study, we developed an alveolar-capillary exchange (ACE) chip aiming to simulate the cellular microenvironment at the alveolar-capillary interface. The ACE chip was designed with two chambers for culturing alveolar epithelial cells and vascular endothelial cells separately, which are separated by a microporous polycarbonate film that allows for the exchange of soluble biomolecules. Using this model, we further tested the toxic effects of fine particulate matter (PM2.5), a form of airborne pollutant known to induce adverse effects on human respiratory system. These effects are largely associated with the ability of PM2.5 to penetrate the alveoli, where it negatively affects the pulmonary function. Our results indicate that alveolar epithelial cells cultured in the ACE chip in solo and coculture with vascular endothelial cells underwent oxidative injury-induced apoptosis mediated via the PEAK-eIF2α signaling pathway of endoplasmic reticulum stress. The use of ACE chip in an alveolar epithelial cell-vascular endothelial cell coculture model revealed cellular vulnerability to PM2.5. Therefore, this chip provides a feasible surrogate approach in vitro for investigating and simulating the cellular microenvironment responses associated with ACE in vivo.

Protein Requirements of Elderly Chinese Adults Are Higher than Current Recommendations.

BACKGROUND: Due to a lack of research data on the protein requirements of the elderly in China, the estimated average requirement (EAR) and the recommended nutrient intake (RNI) of protein in the elderly remain the same as those in young and middle-aged people at 0.98 g/(kg·d). OBJECTIVE: The objective of this study was to determine the protein requirements of healthy Chinese adults >65y old through use of the indicator amino acid oxidation (IAAO) method. METHODS: Seven healthy adult men and 7 healthy adult women participated in the study, with protein intakes ranging from 0.3 to 1.8 g/(kg·d). The diets were isocaloric and provided energy at a 1.5 resting energy expenditure. Protein was given based on the lactalbumin. Phenylalanine and tyrosine were added to protein doses of 0.3-1.5 g/kg according to the highest dose of protein content [1.8 g/(kg·d)]. Phenylalanine and tyrosine concentrations were kept constant at each protein dose. The mean protein requirement was determined by applying a nonlinear mixed-effects model analysis to the F13CO2, which identified a breakpoint in F13CO2 in response to graded amounts of protein. This trial was registered with the Chinese clinical trial registry as ChiCTR-BOC-17010930. RESULTS: Protein EAR and RNI for healthy elderly Chinese adults were determined to be 0.91 and 1.17 g/(kg·d), respectively, based on the indicator amino acid oxidation technique. CONCLUSIONS: The estimates of protein requirements for Chinese adults >65 y in the present study are 3.4% and 19.4% higher than the current estimated requirements, 0.88 g/(kg·d) for EAR and 0.98 g/(kg·d) for RNI.

Increased risk of carotid atherosclerosis for long-term exposure to indoor coal-burning pollution in rural area, Hebei Province, China.

Smoky coal burning is a predominant manner for heating and cooking in most rural areas, China. Air pollution is associated with the risk of atherosclerosis, however, the link between indoor air pollution induced by smoky coal burning and atherosclerosis is not very clear. Therefore, we designed a cross-sectional study to evaluate the association of long-term exposure to smoky coal burning pollutants with the risk of atherosclerosis. 426 and 326 participants were recruited from Nangong, China and assigned as the coal exposure and control group according to their heating and cooking way, respectively. The indoor air quality (PM2.5, CO, SO2) was monitored. The association between coal burning exposure and the prevalence of atherosclerosis was evaluated by unconditional logistic regression analysis, adjusted for confounding factors. The inflammatory cytokines mRNAs (IL-8, SAA1, TNF-α, CRP) expression in whole blood were examined by qPCR. People in the coal exposure group had a higher risk of carotid atherosclerosis compared with the control (risk ratio [RR], 1.434; 95% confidence interval [95%CI], 1.063 to 1.934; P = 0.018). The association was stronger in smokers, drinkers and younger (<45 years old) individuals. The elevation of IL-8 (0.24, 95%CI, 0.06-0.58; P < 0.05), CRP (0.37, 95%CI, 0.05-0.70; P < 0.05), TNF-α (0.41, 95%CI, 0.14-0.67; P < 0.01) mRNAs expression in whole blood were positively related to coal exposure. Our results suggested long-term exposure to smoky coal burning emissions could increase the risk of carotid atherosclerosis. The potential mechanism might relate that coal burning emissions exposure induced inflammatory cytokines elevation which had adverse effects on atherosclerotic plaque, and then promoted the development of atherosclerosis.

An Application-based programme to reinforce and maintain lower salt intake (AppSalt) in schoolchildren and their families in China.

INTRODUCTION: Salt intake is very high in China, with ≈80% being added by the consumers. It is difficult to reduce salt in such settings. Our previous study (School-based Education programme to reduce Salt(School-EduSalt)) demonstrated that educating schoolchildren, who then instructed their families to reduce the amount of salt used at home, is effective in lowering salt intake in both children and adults. Our team also developed an app called 'KnowSalt', which could help individuals to estimate their salt intake and the major sources of salt in the diet. Building on School-EduSalt and KnowSalt, we propose to develop a new app (AppSalt) focusing on salt reduction through education, target setting, monitoring, evaluation, decision support and management to achieve a progressive lower salt intake for long term. To evaluate the effectiveness of the AppSalt programme, we will carry out a cluster randomised controlled trial. METHODS AND ANALYSIS: We will recruit 54 primary schools from urban and rural areas of three provinces in China. A total of 594 children aged 8-9 years and 1188 adult family members will be randomly selected for evaluation. After baseline assessment, schools will be randomly allocated to either the intervention or control group. Children in the intervention group will be taught, with support of AppSalt, about salt reduction and assigned homework to get the whole family involved in the activities to reduce salt consumption. The duration of the intervention is two school terms (ie, 1 year). The primary outcome is the difference between the intervention and control group in the change of salt intake as measured by 24-hour urinary sodium. ETHICS AND DISSEMINATION: The study has been approved by Queen Mary Research Ethics Committee and Peking University Health Science Centre IRB. Results will be disseminated through presentations, publications and social media. TRIAL REGISTRATION NUMBER: ChiCTR1800017553.

[Acute effects of particulate matter pollution on daily emergency ambulance dispatches due to neurological diseases in one haze polluted city of the North China].

OBJECTIVE: To access the relationship between ambient particulate matter( PM_(2. 5)and PM_(10)) concentration and daily emergency ambulance dispatches due to neurological diseases in one city of the North China. METHODS: Semi-parametric generalized additive model was used to analyze the relationship between particulate matter( PM_(2. 5)and PM_(10)) concentration and daily emergency ambulance dispatches due to neurological diseases from January 1, 2013 to December 31, 2015 after adjustment for time trends, weather conditions and "days of the week". RESULTS: An 10 µg/m~3 increase in the lag 03 day concentration of PM_(2. 5)corresponded to increase of 0. 75%( 95% CI0. 34%-1. 17%) in daily emergency ambulance dispatches due to neurological diseases, and an 0. 35%( 95% CI 0. 05%-0. 66%) increase correspondence for PM_(10) in the lag04. CONCLUSION: Outdoor particulate matter( PM_(2. 5)and PM_(10)) concentration is significantly associated with increased risk of emergency ambulance dispatches due to neurological diseases in the North China.

A novel immunotoxin - rCCK8PE38 targeting of CCK-R overexpressed colon cancers.

BACKGROUND: Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, such as pancreatic, colon and gastric cancers. Previous studies have shown that the specific receptor-binding property of CCK for CCK receptors (CCKRs) can be exploited to produce immunotoxins (ITs) that target cancer cells overexpressing CCK receptors. PURPOSE: Construct a new IT-targeting CCKR-overexpressing colon cancers. METHODS: To construct the CCKR-targeted IT, a reverse CCK8 peptide was fused with a modified 38-kDa truncated form of the Pseudomonas exotoxin (PE38KDEL). An efficient immunoaffinity purification procedure was used to produce a PE38-based IT. Several analyses, including CCK8 competition and indirect immunofluorescence assays, were performed to confirm the interaction between rCCK8 and CCKR. After cytotoxic assays on several cell lines, the anti-tumor activity of the new IT was detected in nude mice. RESULTS: The rCCK8PE38 IT showed specific cytotoxicity for two colon cancer cell lines and one gastric cancer cell line. After purification, 18-26 mg of pure rCCK8PE38 per 1 L of culture was obtained. Purified rCCK8PE38 showed high cytotoxicity in colon cancer cell lines with IC50 values of 0.8-3.5 ng/mL. The results of the CCK8 competition and indirect immunofluorescence assays showed that rCCK8 had a specific interaction with CCKR. Nude mice inoculated with HCT-8 tumor xenografts were treated with rCCK8PE38, which efficiently decreased the tumor size in those mice. CONCLUSIONS AND DISCUSSION: All of these data suggest that rCCK8PE38 has potential as a new immunotherapy agent. Furthermore, the results of this study further support the high value of the immunoaffinity method for IT purification procedures.