Small peptides is one of the main components in the final product of protein digestion in the gastrointestinal tract,which plays an important role in protein nutrition.Present studies show that small peptides in the intestine can be absorbed directly into the circulation,which is also the main form of protein absorption in vivo.However,the transporter system of small peptides is independent from that of amino acids.This paper elaborates on the absorption and transport system of small peptides,their advantages in enteral nutrition,and some small peptides with critical physiological functions.

Objective To investigate the expressions of Toll-like receptor 4 (TLR4) and high mobility group box 1 (HMGB1) expression on distant tissue during the intestinal ischemia/reperfusion and the effects of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) intervention in rats.Methods Forty-eight Sprague-Dawley male rats,weighing (281.50 ± 22.68) g,were randomly divided into three groups (n =16) after gastrostomy:normal diet (N) group,enteral nutrition (EN) group and EN plus ω-3 PUFAs (PUFA) group.Each group was further divided into lymph drainage (I/R + D) and non-drainage (I/R) sub-groups (n =8 each) according to whether treated with intestinal lymph drainage.All the rats were subjected to 60 min ischemia by clamping the superior mesenteric artery,followed by 120 min reperfusion,while the rats in the I/R + D subgroups were treated with intestinal lymph drainage for 180 min at the same time.Results The interleukin-6 level in lymph in N (I/R + D) group was significantly higher than in the EN (I/R + D) and PUFA (I/R + D) groups (PUFA vs EN vs N:(154.57 ±69.30) ng/L vs (97.58 ±40.34) ng/L vs (85.35 ±23.93) ng/L,P =0.021).Besides,the serum level of HMGB1 in PUFA (I/R + D) group was significantly lower compared to the other 5 groups [PUFA (I/R) vs EN (I/R) vs N (I/R) vs PUFA (I/R + D) vs EN (I/R + D) vs N (I/R + D):(2.95 ± 1.17) μg/L vs (3.86 ±0.99) μg/L vs (4.45 ± 1.73) μg/L vs (1.71 ±1.41) μg/Lvs (2.11±0.56) μg/Lvs (3.13 ±0.79) μg/L,P=0.000],and it also decreased in the PUFA (I/R) and EN (I/R) groups than the N (I/R) group (respectively,P ＜ 0.05).Furthermore,the serum endotoxin level in PUFA (I/R) group was significantly lower compared to the N (I/R) and EN (I/ R) groups[PUFA(I/R) vsPUFA (I/R+D) vsEN (I/R) vs N (I/R):(0.020±0.004) EU/mlvs (0.028 ±0.006) EU/ml vs (0.028 ±0.005) EU/ml vs (0.018 ±0.006) EU/ml,P=0.014].Together the serum tumor necrosis factor-α level in both PUFA (I/R) and PUFA (I/R + D) groups were significantly lower than theEN (I/R),N (I/R) and N (I/R+D) groups [PUFA (I/R+D) vs PUFA (I/R) vs EN (I/R) vsN (I/R) vs N (I/R+D):(12.03 ±6.57) ng/L vs (14.32 ±6.11) ng/Lvs (23.27 ±15.60)ng/L vs (27.42 ± 10.37) ng/L vs (26.87 ± 5.30) ng/L,P =0.013].The jejunum and ileum mucosa in all the I/R groups showed swelling and atrophy and appeared fragile,while the PUFA groups showed less yellow staining and injury than the other two groups (P ＜ 0.05,respectively).In addition,the expressions of TLR4 mRNA in jejunum,ileum,and liver in all the drainage groups were respectively lower than the corresponding non-drainage groups [jejunum:PUFA (I/R) vs EN (I/R) vs N (I/R) vs PUFA (I/R+D) vs EN (I/R+D) vsN (I/R+D):2.32±0.62vs3.08±1.29vs3.50±2.44vs 1.62±0.79vs 1.67±1.11 vs 1.94±0.81,P=0.025; ileum:PUFA (1/R) vsEN (1/R) vsN (1/R) vs PUFA (1/R+D) vsEN (1/R+D) vs N (1/R+D):2.67±1.08 vs 5.22 ± 3.96 vs 6.95 ±4.92 vs 1.70±0.68 vs 1.80±0.29 vs3.68±1.47,P=0.012; liver:PUFA (1/R)vsEN (1/R)vsN (1/R)vs PUFA (1/R+D)vsEN (1/R+D)vsN (1/R+D):5.67 ±1.94 vs 7.50 ±3.89 vs 7.18 ±4.55 vs 1.70 ±0.86 vs 3.90 ± 1.95 vs 4.12 ±2.11,P =0.001],which was consistent with the reduction of HMGB1 and the decrease of nuclear factor-κB activity in intestine,liver,and lung (P =0.000).Conclusions Lymph drainage and ω-3 PUFAs intervention can reduce the production of HMGB1 and inflammation factors,inhibit the expression of HMGB1 and TLR4 mRNA,and thus alleviate distant tissue injury caused by intestinal L/R.

Objective In order to know first aid awareness and training needs of non-medical college students in Shiyan city,and to provide the basis for an efficient first-aid training.Methods A total of 1063 non-medical colleges in Shiyan city were surveyed by random sampling method.Results 64.61％ of students awared of their own lack of knowledge of first aid,only 3.8 ％ feel rich;based on the first aid knowledge they obtained at present,46.92 ％ did not hesitate to rescue the stranger.After receiving systematic training,the rate rise to 78.9 ％,68.09 ％ of students worried about their lack of first aid skills were the biggest obstacle for them to implement of rescue;98.3％ of the students asked to undergo first aid training,92.27％ of students like approach first aid skills was hands-on model.33.03％ of students believe that medical schools were the best institutions to undertake emergency training,23.46％ of students chose the hospital.Conclusion Non-medical college students in Shiyan city have a bad awareness for firstaid knowledge and a strong desire for training.It is necessary that relevant departments will formulate targeted training programs to improve college students' first-aid response and improve regional emergency level.

BACKGROUNDTo establish a sandwich ELISA method for detection of reporter chloramphenicol acetyltransferase (CAT) gene.

METHODSThe full length sequence of CAT gene was amplified with PCR using plasmid pBLCAT6 as template, and inserted into the prokaryotic expression plasmid Pgex-2T. The purified fusion protein was emulsified with complete or incomplete Freund adjuvant and injected subcutaneously into rabbits. The antibody was labeled with biotin, and a sandwich ELISA technique with biotin streptavidin amplify system was established. Several CAT reporter plasmids containing different HPV 16 LCR sequences were generated and transfected transiently to monolayer cells in vitro. The cytoplasm proteins were extracted and the expressions of CAT were evaluated with the newly established ELISA assay.

RESULTSSDS-PAGE displayed that the molecular weight of the expressed fusion protein was about 54,000. The prepared antiserum was able to recognize the CAT protein expressed by mammalian cells or prokaryote cells. Under the control of different promoters and their regulate sequences,two to eight folds CAT expression increased were evaluated in transiently transfected mammalian cells by the newly established sandwich ELISA method.

CONCLUSIONSThe established method could sensitively reflect the activities of the upstream promoters, as well as the influence of exchanges of nucleotides within the regulate region on the promoter activities. Therefore, it proposes a convenient assay for the studies using CAT as the reporter gene.

Animals ; Antibodies ; analysis ; Cells, Cultured ; Chloramphenicol O-Acetyltransferase ; analysis ; genetics ; immunology ; Enzyme-Linked Immunosorbent Assay ; methods ; Genes, Reporter ; Male ; Papillomaviridae ; genetics ; Plasmids ; genetics ; Rabbits ; Recombinant Fusion Proteins ; analysis ; biosynthesis ; immunology

Background The concentrations of disinfection by-products (DBPs) are varied by different water sources, disinfectants, or treatment processes in Wuxi, and the associated health risks are also different. Objective To understand the levels of trihalomethanes (THMs) and haloacetamides (HAcAms) in drinking water in Wuxi, and their variations by water sources, seasons, disinfectants or treatment processes, aiming to provide technical support for ensuring the safety of drinking water. Methods In dry period (December 2019) and wet period (July 2020), the finished water and tap water (from the beginning, middle, and end of the drinking water distribution network) from 12 centralized water treatment plants in Wuxi were collected to detect the concentrations of THMs and HAcAms in water samples. A purge and trap-gas chromatography-mass spectrometry method was applied to detect trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM), and a solid-phase extraction-gas chromatography-mass spectrometry method to detect dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), bromochloroacetamide (BCAcAm), dibromoacetamide (DBAcAm), bromodichloroacetamide (BDCAcAm), dibromochloroacetamide (DBCAcAm), and tribromoacetamide (TBAcAm). Analyses and comparisons were made on the concentrations of THMs and HAcAms in drinking water by water sources (the Yangtze River/the Taihu Lake/reservoir), wet/dry seasons, disinfection methods (liquid chlorine/sodium hypochlorite), and treatment processes (conventional treatment/conventional+advanced treatment). Results A total of 96 drinking water samples were collected in Wuxi. THMs were positive in all the water samples (100%), with concentration ranging from 1.027 to 40.225 μg·L⁻¹ and the M (P₂₅, P₇₅) concentration being 24.782 (17.784, 30.932) μg·L⁻¹. None of the 4 THMs exceeded the standard limit of the Standards for drinking water quality (GB 5749-2022 ), and the order of the 4 THMs concentrations from high to low was TCM > BDCM > DBCM > TBM. Five of the 7 HAcAms were detected, the total concentration ranged from 0.137 to 3.288 μg·L⁻¹, and the M (P₂₅, P₇₅) was 0.808 (0.482, 1.704) μg·L⁻¹. The DCAcAm concentration was the highest (2.448 μg·L⁻¹), followed by BCAcAm, while TCAcAm and DBCAcAm were not detected. The M (P₂₅, P₇₅) of the total concentration of THMs in the drinking water from the Taihu Lake was 33.353 (26.649, 36.217) μg·L⁻¹, that of the Yangtze River was 27.448 (24.312, 31.393) μg·L⁻¹, and both were higher than the level of the reservoir [16.359 (2.305, 21.553) μg·L⁻¹] (P<0.05), while the M (P₂₅, P₇₅) of the total concentration of HAcAms in the drinking water from the Taihu Lake was 0.616 (0.363, 0.718) μg·L⁻¹, which was lower than those of the Yangtze River [0.967 (0.355, 2.283) μg·L⁻¹] and the reservoir [1.071 (0.686, 1.828) μg·L⁻¹] (P<0.05). There were no statistically significant differences in the total concentrations of THMs and HAcAms between wet season and dry season, or between different disinfection methods (P>0.05). The M (P₂₅, P₇₅) concentrations of THMs and HAcAms in drinking water after advanced treatment process involving ozone, activated carbon, and membrane were 20.565 (3.316, 27.185) μg·L⁻¹ and 0.623 (0.452, 1.286) μg·L⁻¹ respectively, and were lower than the corresponding values after conventional treatment process, 28.740 (23.431, 35.085) μg·L⁻¹ and 0.934 (0.490, 2.116) μg·L⁻¹ respectively (P＜0.05). Conclusion The concentrations of THMs and HAcAms in drinking water in Wuxi are generally at a low level. The levels of controlled THMs meet the requirements of national standards, and the levels of uncontrolled HAcAms as new DBPs are up to μg·L⁻¹. The concentrations of the two kinds of DBPs in drinking water vary by water sources. The concentrations of THMs and HAcAms produced by the advanced treatment process are lower than that by the conventional treatment process.

OBJECTIVETo analyze the genetic polymorphism of D16S539, D7S820 and D13S317 in Chinese Kazak ethnic population from Xinjiang.

METHODSOne hundred and two unrelated individuals and a sample of families (n=42) were investigated by multiplex amplification, 6% denaturing PAGE and silver staining. And, the obtained allele frequencies were compared with those of other populations.

RESULTSEight, seven, eight alleles were observed at the 3 STR loci respectively and the genotypes distributions were in accordance with Hardy-Weinberg equilibrium. The expected heterozygosities for these loci were 0.9439, 0.9356 and 0.9304; the calculated polymorphism formation content (PIC) was 0.9905; the discrimination power (DP), 0.9998; the paternity exclusion (PE), 0.9572. In addition, significant difference was found in comparison with other populations, and in the sample of families (n=42) no new mutations could be found.

CONCLUSIONThe multiplex examination of 3 STR loci can be used in forensic identification and population genetics research.

China ; ethnology ; European Continental Ancestry Group ; genetics ; Female ; Gene Frequency ; Genetics, Population ; Genotype ; Humans ; Male ; Polymorphism, Genetic ; Tandem Repeat Sequences ; genetics