Cardiovascular disease (CVD) remains one of the leading causes of mortality among adults globally, with continuously rising morbidity and mortality rates. Metabolic disorders are closely linked to various cardiovascular diseases and play a critical role in their pathogenesis and progression, involving multifaceted mechanisms such as altered substrate utilization, mitochondrial structural and functional dysfunction, and impaired ATP synthesis and transport. In recent years, the potential role of peroxisome proliferator-activated receptors (PPARs) in cardiovascular diseases has garnered significant attention, particularly peroxisome proliferator-activated receptor alpha (PPARα), which is recognized as a highly promising therapeutic target for CVD. PPARα regulates cardiovascular physiological and pathological processes through fatty acid metabolism. As a ligand-activated receptor within the nuclear hormone receptor family, PPARα is highly expressed in multiple organs, including skeletal muscle, liver, intestine, kidney, and heart, where it governs the metabolism of diverse substrates. Functioning as a key transcription factor in maintaining metabolic homeostasis and catalyzing or regulating biochemical reactions, PPARα exerts its cardioprotective effects through multiple pathways: modulating lipid metabolism, participating in cardiac energy metabolism, enhancing insulin sensitivity, suppressing inflammatory responses, improving vascular endothelial function, and inhibiting smooth muscle cell proliferation and migration. These mechanisms collectively reduce the risk of cardiovascular disease development. Thus, PPARα plays a pivotal role in various pathological processes via mechanisms such as lipid metabolism regulation, anti-inflammatory actions, and anti-apoptotic effects. PPARα is activated by binding to natural or synthetic lipophilic ligands, including endogenous fatty acids and their derivatives (e.g., linoleic acid, oleic acid, and arachidonic acid) as well as synthetic peroxisome proliferators. Upon ligand binding, PPARα activates the nuclear receptor retinoid X receptor (RXR), forming a PPARα-RXR heterodimer. This heterodimer, in conjunction with coactivators, undergoes further activation and subsequently binds to peroxisome proliferator response elements (PPREs), thereby regulating the transcription of target genes critical for lipid and glucose homeostasis. Key genes include fatty acid translocase (FAT/CD36), diacylglycerol acyltransferase (DGAT), carnitine palmitoyltransferase I (CPT1), and glucose transporter (GLUT), which are primarily involved in fatty acid uptake, storage, oxidation, and glucose utilization processes. Advancing research on PPARα as a therapeutic target for cardiovascular diseases has underscored its growing clinical significance. Currently, PPARα activators/agonists, such as fibrates (e.g., fenofibrate and bezafibrate) and thiazolidinediones, have been extensively studied in clinical trials for CVD prevention. Traditional PPARα agonists, including fenofibrate and bezafibrate, are widely used in clinical practice to treat hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C) levels. These fibrates enhance fatty acid metabolism in the liver and skeletal muscle by activating PPARα, and their cardioprotective effects have been validated in numerous clinical studies. Recent research highlights that fibrates improve insulin resistance, regulate lipid metabolism, correct energy metabolism imbalances, and inhibit the proliferation and migration of vascular smooth muscle and endothelial cells, thereby ameliorating pathological remodeling of the cardiovascular system and reducing blood pressure. Given the substantial attention to PPARα-targeted interventions in both basic research and clinical applications, activating PPARα may serve as a key therapeutic strategy for managing cardiovascular conditions such as myocardial hypertrophy, atherosclerosis, ischemic cardiomyopathy, myocardial infarction, diabetic cardiomyopathy, and heart failure. This review comprehensively examines the regulatory roles of PPARα in cardiovascular diseases and evaluates its clinical application value, aiming to provide a theoretical foundation for further development and utilization of PPARα-related therapies in CVD treatment.

Objective To compare the efficacy and safety of Saccharomyces boulardii and other probiotics in the treatment of pediatric diarrhea.Methods Retrieved from PubMed,Embase,CBM,Wanfang data,CNKI and VIP,randomized controlled trial(RCTs)about Saccharomyces boulardii(treatment group)vs other probiotics(control group)were collected.After screening the literature,extracting data and evaluating the quality,Meta-analysis was performed by using RevMan 5.3 and Stata 17.0 software.Results A total of 30 RCTs were included,involving 3 082 children.Results of Meta-analysis showed there was no statistical significance in the duration of diarrhea[mean difference(MD)=-0.65,95％confidence interval(CI)=-1.44-0.14,P＞0.05]or the total incidence of adverse reactions[odds ratio(OR)=0.85,95％CI=0.44-1.62,P＞0.05].The total effective rate(OR=1.60,95％CI=1.08-2.36,P＜0.05)and the number of stools(MD=-0.66,95％CI=-1.00--0.32,P＜0.01)in the treatment group were significantly better than control group.There was statistically significant difference in the duration of diarrhea between the two groups treated with diarrhea with fever(MD=1.81,95％CI=1.12-2.49,P＜0.01)and rotavirus gastroenteritis(MD=-0.92,95％CI=-1.20--0.64,P＜0.01).In the treatment of diarrhea with fever,the duration of diarrhea in the control group was significantly shorter than that in the treatment group.The duration of diarrhea in the treatment group was significantly shorter than that control group.At the same time,the duration of diarrhea in children with diarrhea treated with treatment group was significantly shorter than that of control group Bifidobacterium tetragenous viable(MD=-0.84,95％CI=-1.09--0.58,P＜0.01)and control group combined Bacillus subtilis and Enterococcus faecium enteric-coated(MD=-1.35,95％CI=-2.30-0.39,P＜0.01).Conclusion The safety of Saccharomyces boulardii are similar to other probiotics.The efficacy and the number of stools with Saccharomyces boulardii are significantly better than other probiotics in the treatment of diarrhea.The duration of diarrhea in Saccharomyces boulardii group was significantly shorter than other probiotics,while in the treatment of antibiotic-associated diarrhea,the duration of diarrhea of Saccharomyces boulardii was the same as that of other probiotics.However,the duration of diarrhea in children with diarrhea treated with Saccharomyces boulardii was significantly longer than other probiotics.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

Objective To study the distribution characteristics of gut microbiota in young children infected with rotavirus and adenovirus,providing new ideas for treatment and improving prognosis.Methods Fecal samples of 22 young children clinically diagnosed with acute diarrhea were collected,including 12 confirmed cases of rotavirus infection and 10 adenovirus infections,and 12 fecal samples of healthy children during the same period were collected as controls.Using 16S rDNA targeted amplification to detect the diversity and composition structure of gut microbiota in three groups of young children,analyzing their microbial community structure,abundance,and differences.Results There were significant differences in the alpha and beta diversity analyses of the gut microbiota among the three groups of observing objects.At the family level,the healthy control group and adenovirus group were mainly dominated by the Trichospiridae family,while the rotavirus group is mainly dominated by the Enterobacteriaceae family;At the genus level,the healthy control group,rotavirus group,and adenovirus group have the highest abundance of Bacteroides,Escherichia/Shigella,and Bifidobacterium,respectively;LEfSe differential analysis showed that compared with the healthy control group,the abundance of probiotics such as Bifidobacterium,Ackermann's bacteria,Ruminococcus,and Eubacterium in the rotavirus group was significantly reduced,but the abundance of Gram negative bacteria such as Escherichia/Shigella was increased;The abundance of conditional pathogenic bacteria such as Clostridium and Staphylococcus in the adenovirus group was significantly increased,while the abundance of Bacillus was lowered,and Bifidobacterium did not decrease compared to the control group.Conclusion Both rotavirus and adenovirus infections cause dysbiosis of the gut microbiota in young children,and there are significant differences in the types and distribution of microbiota in their bodies after infection,indicating differences in the use and selection of probiotics in the treatment of diarrhea caused by the two viruses.

Pharmacokinetics of traditional Chinese medicine(TCM)is a discipline that adopts pharmacokinetic research methods and techniques under the guidance of TCM theories to elucidate the dynamic changes in the absorption,distribution,metabolism and excretion of active ingredients,active sites,single-flavour Chinese medicinal and compounded formulas of TCM in vivo.However,the sources and components of TCM are complex,and the pharmacodynamic substances and mechanisms of action of the majority of TCM are not yet clear,so the pharmacokinetic study of TCM is later than that of chemical medicines,and is far more complex than that of chemical medicines,and its development also confronts with challenges.The pharmacokinetic study of TCM originated in the 1950s and has experienced more than 70 years of development from the initial in vivo study of a single active ingredient,to the pharmacokinetic and pharmacodynamic study of active ingredients,to the pharmacokinetic study of compound and multi-component of Chinese medicine.In recent years,with the help of advanced extraction,separation and analysis technologies,gene-editing animals and cell models,multi-omics technologies,protein purification and structure analysis technologies,and artificial intelligence,etc.,the pharmacokinetics of TCM has been substantially applied in revealing and elucidating the pharmacodynamic substances and mechanisms of action of Chinese medicines,research and development of new drugs of TCM,scientific and technological upgrading of large varieties of Chinese patent medicines,as well as guiding the rational use of medicines in clinics.Pharmacokinetic studies of TCM have made remarkable breakthroughs and significant development in theory,methodology,technology and application.In this paper,the history of the development of pharmacokinetics of TCM and the progress of cutting-edge research was reviewed,with the aim of providing ideas and references for the pharmacokinetics of TCM and related research.

Objective To explore the distribution patterns of tongue and pulse manifestations and traditional Chinese medicine(TCM)syndrome elements in ischemic stroke(IS)patients of different genders and ages,thus to provide approaches for the prevention and treatment of stroke with TCM.Methods The criteria of six syndrome elements in Diagnostic Scale of Syndrome Elements in Ischemic Stroke were used for the comprehensive identification of syndrome elements in 5 254 cases of inpatients confirmed as IS at the first visit in Shenzhen Traditional Chinese Medicine Hospital from 2017 to 2023.Moreover,the tongue proper,tongue coating,and whose pulse manifestations ranking in the top five in terms of the frequency of occurrence were collected for comparison and analysis.Results(1)For the distribution of TCM syndrome elements in 5 254 cases of IS patients,phlegm-dampness syndrome was the most common syndrome type(3 544 cases,67.5%),and then came qi deficiency syndrome(653 cases,12.4%)and yin deficiency syndrome(453 cases,8.6%).There were statistically significant differences in the distribution of phlegm-dampness syndrome,internal heat syndrome,and yin deficiency syndrome between the male and the female(P＜0.01).And the distribution of phlegm-dampness syndrome,qi deficiency syndrome,internal wind syndrome,and internal heat syndrome in the youth differed from that in the middle-aged and elderly(P＜0.01).(2)The tongue and pulse manifestations in IS patients with the leading six detection rates which ranked in descending order of frequency of occurrence were as follows:dull tongue(1 993 cases,37.9%),dark red tongue(1 907 cases,36.3%),thin and white coating(1 885 cases,35.9%),wiry and slippery pulse(1 714 cases,32.6%),white and greasy coating(1 679 cases,32.0%),and wiry and thready pulse(1 609 cases,30.6%).The detection rates of tongue and pulse manifestations such as light red tongue,thin and white coating in the youth group were significantly higher than those in the middle-aged and elderly group,and the detection rates of dark red tongue,and tooth-marked tongue in the middle-aged and elderly group were significantly higher than those in the youth group,the differences all being statistically significant(P＜0.05).The female patients had higher detection rates of dull tongue,thin and white coating,thin and yellow coating,wiry and thready pulse,and deep and thready pulse than male patients,while the male patients had higher detection rates of dark red tongue,red tongue,white and greasy coating,yellow and thick-greasy coating,white and thick-greasy coating,wiry and slippery pulse,and slippery pulse than the females,and the differences were all statistically significant(P＜0.05 or P＜0.01).Higher detection rate of thin and white coating was shown in the youth female than that in the youth male,while higher detection rate of wiry and slippery pulse was shown in the youth male than that in the youth female,and the differences were all statistically significant(P＜0.05 or P＜0.01).The middle-aged and elderly female patients had higher detection rates of dull tongue,thin and white coating,wiry and thready pulse,and deep and thready pulse than the middle-aged and elderly male patients,while the middle-aged and elderly male patients had higher detection rates of dark red tongue,red tongue,white and greasy coating,white and thick-greasy coating,yellow and thick-greasy coating,wiry and slippery pulse,and slippery pulse than the middle-aged and elderly female patients,the differences being all statistically significant(P＜0.05 or P＜0.01).Conclusion Phlegm-dampness syndrome,qi deficiency syndrome,and yin deficiency syndrome exert a significant effect on IS,and phlegm-dampness syndrome is the most common syndrome type.Factors such as gender and age have influences on the distribution of TCM syndrome in patients with IS.

Objective To investigate the nutritional status of children with Crohn's Disease (CD) at diagnosis and its association with clinical characteristics. Methods A retrospective analysis was performed for the clinical data and nutritional status of 118 children with CD who were admitted to Beijing Children's Hospital,Capital Medical University,from January 2016 to January 2024. A multivariate logistic regression analysis was used to investigate the risk factors for malnutrition. Results A total of 118 children with CD were included,among whom there were 68 boys (57.6％) and 50 girls (42.4％),with a mean age of (11±4) years. Clinical symptoms mainly included recurrent abdominal pain (73.7％,87/118),diarrhea (37.3％,44/118),and hematochezia (32.2％,38/118),and 63.6％ (75/118) of the children had weight loss at diagnosis. The incidence rate of malnutrition was 63.6％ (75/118),and the children with moderate or severe malnutrition accounted for 67％ (50/75). There were 50 children (42.4％) with emaciation,8 (6.8％) with growth retardation,and 9 (7.6％) with overweight or obesity. Measurement of nutritional indices showed a reduction in serum albumin in 83 children (70.3％),anemia in 74 children (62.7％),and a reduction in 25 hydroxyvitamin D in 15 children (60％,15/25). The children with malnutrition had significantly higher disease activity,proportion of children with intestinal stenosis,and erythrocyte sedimentation rate and a significant reduction in serum albumin (P<0.05). The multivariate logistic regression analysis showed that intestinal stenosis was an independent risk factor for malnutrition in children with CD (OR=4.416,P<0.05). Conclusions There is a high incidence rate of malnutrition in children with CD at diagnosis,which is associated with disease activity and disease behavior. The nutritional status of children with CD should be closely monitored.

Objective To compare image quality and radiation dose for abdominal CT angiography(CTA)in infants and young children after liver transplantation using energy spectrum CT and low tube voltage scanning.Methods Totally 41 infants or young children after liver transplantation were included,including 22 cases who underwent energy spectrum CT(energy spectrum group)and 19 cases who underwent low tube voltage(80 kV)CT scanning(low tube voltage group).50 keV single energy images of energy spectrum group were extracted to observe abdominal blood vessels.Subjective and objective evaluation on image quality were performed,the latter aimed at CT value and noise value of hepatic artery and portal vein,the contrast and contrast-to-noise ratio(CNR)of hepatic artery and portal vein.The examined volume CT dose index(CTDIvol),dose-length product(DLP)and effective dose(ED)of both groups were recorded.Results No significant difference of subjective image quality score was found between groups(P＞0.05).In low tube voltage group,during arterial phase,CT values of hepatic artery,contrastarteries and CNRarteries were higher,and during the portal vein phase,CT values of hepatic artery,liver tissue noise,contrastportalvein and CNRportalvein were all higher than those in energy spectrum group(all P＜0.05).CTDIvol,DLP and ED in energy spectrum group were higher than those in low tube voltage group(all P＜0.05).Conclusion Compared with energy spectrum CT,low tube voltage CT scanning combined with iterative reconstruction technology could result better image quality and lower radiation dose for abdominal CTA in infants and young children after liver transplantation.

This study aimed to elucidate the effect and underlying mechanism of Bovis Calculus in the treatment of ulcerative colitis(UC) through network pharmacological prediction and animal experimental verification. Databases such as BATMAN-TCM were used to mine the potential targets of Bovis Calculus against UC, and the pathway enrichment analysis was conducted. Seventy healthy C57BL/6J mice were randomly divided into a blank group, a model group, a solvent model(2% polysorbate 80) group, a salazosulfapyridine(SASP, 0.40 g·kg~(-1)) group, and high-, medium-, and low-dose Bovis Calculus Sativus(BCS, 0.20, 0.10, and 0.05 g·kg~(-1)) groups according to the body weight. The UC model was established in mice by drinking 3% dextran sulfate sodium(DSS) solution for 7 days. The mice in the groups with drug intervention received corresponding drugs for 3 days before modeling by gavage, and continued to take drugs for 7 days while modeling(continuous administration for 10 days). During the experiment, the body weight of mice was observed, and the disease activity index(DAI) score was recorded. After 7 days of modeling, the colon length was mea-sured, and the pathological changes in colon tissues were observed by hematoxylin-eosin(HE) staining. The levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), interleukin-6(IL-6), and interleukin-17(IL-17) in colon tissues of mice were detected by enzyme-linked immunosorbent assay(ELISA). The mRNA expression of IL-17, IL-17RA, Act1, TRAF2, TRAF5, TNF-α, IL-6, IL-1β, CXCL1, CXCL2, and CXCL10 was evaluated by real-time polymerase chain reaction(RT-PCR). The protein expression of IL-17, IL-17RA, Act1, p-p38 MAPK, and p-ERK1/2 was investigated by Western blot. The results of network pharmacological prediction showed that Bovis Calculus might play a therapeutic role through the IL-17 signaling pathway and the TNF signaling pathway. As revealed by the results of animal experiments, on the 10th day of drug administration, compared with the solvent model group, all the BCS groups showed significantly increased body weight, decreased DAI score, increased colon length, improved pathological damage of colon mucosa, and significantly inhibited expression of TNF-α,IL-6,IL-1β, and IL-17 in colon tissues. The high-dose BCS(0.20 g·kg~(-1)) could significantly reduce the mRNA expression levels of IL-17, Act1, TRAF2, TRAF5, TNF-α, IL-6, IL-1β, CXCL1, and CXCL2 in colon tissues of UC model mice, tend to down-regulate mRNA expression levels of IL-17RA and CXCL10, significantly inhibit the protein expression of IL-17RA,Act1,and p-ERK1/2, and tend to decrease the protein expression of IL-17 and p-p38 MAPK. This study, for the first time from the whole-organ-tissue-molecular level, reveals that BCS may reduce the expression of pro-inflammatory cytokines and chemokines by inhibiting the IL-17/IL-17RA/Act1 signaling pathway, thereby improving the inflammatory injury of colon tissues in DSS-induced UC mice and exerting the effect of clearing heat and removing toxins.
Mice ; Animals ; Colitis, Ulcerative/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/metabolism* ; Interleukin-17/pharmacology* ; TNF Receptor-Associated Factor 2/pharmacology* ; TNF Receptor-Associated Factor 5/metabolism* ; Mice, Inbred C57BL ; Signal Transduction ; Colon ; p38 Mitogen-Activated Protein Kinases/metabolism* ; RNA, Messenger/metabolism* ; Dextran Sulfate/metabolism* ; Disease Models, Animal