Middle Colon Research Articles

Bisphenol-A alters microbiota metabolites derived from aromatic amino acids and worsens disease activity during colitis.

Inflammatory bowel disease is a complex collection of disorders. Microbial dysbiosis as well as exposure to toxins including xenoestrogens are thought to be risk factors for inflammatory bowel disease development and relapse. Bisphenol-A has been shown to exert estrogenic activity in the colon and alter intestinal function, but the role that xenoestrogens, such as bisphenol-A , play in colonic inflammation has been previously described but with conflicting results. We investigated the ability of bisphenol-A to exacerbate colonic inflammation and alter microbiota metabolites derived from aromatic amino acids in an acute dextran sulfate sodium-induced colitis model. Female C57BL/6 mice were ovariectomized and exposed to bisphenol-A daily for 15 days. Disease activity measures include body weight, fecal consistency, and rectal bleeding. Colons were scored for inflammation, injury, and nodularity. Alterations in the levels of microbiota metabolites derived from aromatic amino acids known to reflect phenotypic changes in the gut microbiome were analyzed. Bisphenol-A exposure increased mortality and worsened disease activity as well as inflammation and nodularity scores in the middle colon region following dextran sulfate sodium exposure. Unique patterns of metabolites were associated with bisphenol-A consumption. Regardless of dextran sulfate sodium treatment, bisphenol-A reduced levels of tryptophan and several metabolites associated with decreased inflammation in the colon. This is the first study to show that bisphenol-A treatment alone can reduce microbiota metabolites derived from aromatic amino acids in the colon which may be associated with increased colonic inflammation and inflammatory bowel disease. Impact statement As rates of inflammatory bowel disease rise, discovery of the mechanisms related to the development of these conditions is important. Environmental exposure is hypothesized to play a role in etiology of the disease, as are alterations in the gut microbiome and the metabolites they produce. This study is the first to show that bisphenol-A alone alters tryptophan and microbiota metabolites derived from aromatic amino acids in a manner consistent with autoimmune diseases, specifically inflammatory bowel diseases, regardless of dextran sulfate sodium treatment. These findings indicate a potential mechanism by which bisphenol-A negatively affects gut physiology to exacerbate inflammation.

Earliest known hominin activity in the Philippines by 709 thousand years ago.

Over 60 years ago, stone tools and remains of megafauna were discovered on the Southeast Asian islands of Flores, Sulawesi and Luzon, and a Middle Pleistocene colonization by Homo erectus was initially proposed to have occurred on these islands1-4. However, until the discovery of Homo floresiensis in 2003, claims of the presence of archaic hominins on Wallacean islands were hypothetical owing to the absence of in situ fossils and/or stone artefacts that were excavated from well-documented stratigraphic contexts, or because secure numerical dating methods of these sites were lacking. As a consequence, these claims were generally treated with scepticism 5 . Here we describe the results of recent excavations at Kalinga in the Cagayan Valley of northern Luzon in the Philippines that have yielded 57 stone tools associated with an almost-complete disarticulated skeleton of Rhinoceros philippinensis, which shows clear signs of butchery, together with other fossil fauna remains attributed to stegodon, Philippine brown deer, freshwater turtle and monitor lizard. All finds originate from a clay-rich bone bed that was dated to between 777 and 631 thousand years ago using electron-spin resonance methods that were applied to tooth enamel and fluvial quartz. This evidence pushes back the proven period of colonization 6 of the Philippines by hundreds of thousands of years, and furthermore suggests that early overseas dispersal in Island South East Asia by premodern hominins took place several times during the Early and Middle Pleistocene stages1-4. The Philippines therefore may have had a central role in southward movements into Wallacea, not only of Pleistocene megafauna 7 , but also of archaic hominins.

Is primary sidedness a prognostic factor in patients with resected colon cancer liver metastases (CLM)?

Recent studies have suggested that sidedness of origin from colorectal adenocarcinomas is a predictor of survival, however the impact of this factor in patients with resected colon cancer liver metastases (CLM) is not clear. So, in this study, we compared clinic and pathologic characteristics and long-term survival of patients with resected CLM according to the primary tumor location. This is a retrospective analyzes of a prospective database. Patients with resected CLM from 1998 to 2012 were included. Right colon included tumors from cecum to middle transverse colon, and left colon included tumors from splenic flexure to sigmoid. One hundred fifty-one patients were included, 27 right colon and 124 left colon. In the latter group, there were more patients with synchronous disease (67.7 × 6.2%, P = 0.026) and a higher CEA (22.0 × 11.7 ng/mL, P = 0.001). However, K-Ras mutation was more frequent in right sided tumors (75.0 × 24.1%, P = 0.001). There was no difference in long term survival in both groups in this series even when adjusted for the confounding variables. Sidedness do not seem to be a predictor of long term survival in patients with resected colon cancer liver metastases.

Key vessels assessment and operation highlights in laparoscopic extended right hemicolectomy

Laparoscopic radical colectomies have been more widely used gradually, among which laparoscopic extended right hemicolectomy is considered as the most difficult procedure. The difficulty of extended right hemicolectomy lies in the need to dissect lymph nodes along the superior mesenteric vein (SMV) and disconnect numerous and possible aberrant vessels. To address this problem, we emphasize two points in key vessel assessment: getting familiar with the anatomy along the medial-to-lateral approach and having a good understanding about the preoperative imaging presentations. An accurately preoperative imaging assessment by abdominal enhanced CT can help the surgeon understand the relative position of the key vessels to be dealt with during operation and the situation of the possible aberrant vessels so as to guide the procedure more effectively and facilitate the prevention and management of the intraoperative complications. During operation, the operator should pay special attention to the management of the vessels in the ileocolic vessel region, Henle's trunk and middle colon vessels. The operation highlights of the key vessels are as follows: (1) The ileocolic vessels: identifying the Toldt's gap correctly and opening the vascular sheath of the SMV securely; making sure that the duodenum is well protected. (2) Henle's trunk: dissecting along the surface of the Henle's trunk; preserving the anterior superior pancreaticoduodenal vein (ASPDV) and main trunk of the Henle's trunk; disconnecting the roots of the right colic vein (RCV) and right gastroepiploic vein (RGEV), and then dissecting lymph nodes along the surface of the pancreas. (3) The middle colon vessels: identifying the root of the middle colon vessel along the lower edge of the pancreas; avoiding entering behind the pancreas; mobilizing the transverse mesocolon sufficiently along the surface of the pancreas. Finally, we discuss and analyze the disputes currently existing in laparoscopic extended right hemicolectomy, including dissection of No.6 lymph nodes, naking the SMA and dissecting lymph nodes around the roots of the branches of SMA. This article shares our experience about laparoscopic extended right hemicolectomy, hoping that it could help beginners master the technique more safely and skillfully.

Veillonella Catalase Protects the Growth of Fusobacterium nucleatum in Microaerophilic and Streptococcus gordonii-Resident Environments.

The oral biofilm is a multispecies community in which antagonism and mutualism coexist among friends and foes to keep an ecological balance of community members. The pioneer colonizers, such as Streptococcus gordonii, produce H2O2 to inhibit the growth of competitors, like the mutans streptococci, as well as strict anaerobic middle and later colonizers of the dental biofilm. Interestingly, Veillonella species, as early colonizers, physically interact (coaggregate) with S. gordonii A putative catalase gene (catA) is found in most sequenced Veillonella species; however, the function of this gene is unknown. In this study, we characterized the ecological function of catA from Veillonella parvula PK1910 by integrating it into the only transformable strain, Veillonella atypica OK5, which is catA negative. The strain (OK5-catA) became more resistant to H2O2 Further studies demonstrated that the catA gene expression is induced by the addition of H2O2 or coculture with S. gordonii Mixed-culture experiments further revealed that the transgenic OK5-catA strain not only enhanced the growth of Fusobacterium nucleatum, a strict anaerobic periodontopathogen, under microaerophilic conditions, but it also rescued F. nucleatum from killing by S. gordonii A potential role of catalase in veillonellae in biofilm ecology and pathogenesis is discussed here.IMPORTANCEVeillonella species, as early colonizers, can coaggregate with many bacteria, including the initial colonizer Streptococcus gordonii and periodontal pathogen Fusobacterium nucleatum, during various stages of oral biofilm formation. In addition to providing binding sites for many microbes, our previous study also showed that Veillonella produces nutrients for the survival and growth of periodontal pathogens. These findings indicate that Veillonella plays an important "bridging" role in the development of oral biofilms and the ecology of the human oral cavity. In this study, we demonstrated that the reducing activity of Veillonella can rescue the growth of Fusobacterium nucleatum not only under microaerophilic conditions, but also in an environment in which Streptococcus gordonii is present. Thus, this study will provide a new insight for future studies on the mechanisms of human oral biofilm formation and the control of periodontal diseases.

Estradiol Has Differential Effects on Acute Colonic Inflammation in the Presence and Absence of Estrogen Receptor β Expression.

Inflammatory bowel disease (IBD) increases the risk of developing colon cancer. This risk is higher in men compared to women, implicating a role for female hormones in the protection against this disease. Studies from our laboratory demonstrated that estradiol (E2) protects against inflammation-associated colon tumor formation when administered following chemical carcinogen and induction of chronic colitis. This study seeks to better understand the effect of E2 on acute colitis in the presence and absence of estrogen receptor β (ERβ). Inflammation was induced by 2,4,6-trinitrobenzenesulfonic acid in wild-type (WT) and ERβ knockout (ERβKO) mice implanted with a control or E2-containing pellet and killed 5days later. Inflammation and injury were scored by a pathologist. Apoptosis and proliferation were assessed by immunohistochemistry. Cytokines were measured by multiplex analysis. E2 treatment reduced inflammation in the middle colon in WT mice and the distal colon in ERβKO mice compared to control mice. WT mice had reduced IL-6, IL-12, IL-17, GM-CSF, IFN-γ, MCP-1, MIP-1α, and TNF-α, and ERβKO had reduced IL-6 and IFN-γ expression in response to E2. Injury scores were lower in E2-treated ERβKO mice compared to control ERβKO mice. ERβKO mice had increased proliferation in the basal third of crypts in the distal colon and decreased apoptosis in the proximal colon. These data suggest that E2 has differential protective effects against acute colitis in the presence or absence of ERβ and provide insight into how E2 may protect against IBD.

Influence of different inclusion levels and chain length of inulin on microbial ecology and the state of mucosal protective barrier in the large intestine of young pigs

The objective of the study was to examine the effect of inulin level, in regard to its degree of polymerisation (DP), on microbial activity and mucosal immune system of the large intestine of pigs. A total of 56 castrated male piglets (PIC × Penarlan P76) were allocated to seven groups and fed from the 10th day of life cereal-based diets without the addition of inulin or with 1%, 2% or 3% of inulin with an average DP of 10 (IN10) or 23 (IN23). Pigs were sacrificed at the age of 50 days. Feeding IN10 diets increased fructan concentration in the large intestine compared with IN23 diets, but did not affect microbial activity, except for digesta pH and mucinase activity in the middle colon, which were greater at the 1% level compared with the control group and other IN10 diets, respectively. The concentration of secretory immunoglobulin A in the caecum and middle colon was reduced by the 1% IN10 diet compared with the control group. Pigs fed the 2% IN23 diet had a higher butyric acid concentration in the caecum and proximal colon and greater isoacid concentrations in the middle and distal colon in comparison to the control. Dietary level of IN23 did not affect secretory immunoglobulin A concentration but the count of caecal intraepithelial lymphocytes was higher in pigs on the 1% IN23 diet than on the control diet. Neither IN10 nor IN23 diets affected populations of Bifidobacterium or Lactobacillus spp. In conclusion, the effects of inulin in the large intestine of pigs depended on dietary level and DP. IN23 increased short-chain fatty acid production at the 2% level and slightly activated mucosal immune status at the 1% level.

Molecular characterization of pneumococcal surface protein K, a potential pneumococcal vaccine antigen

ABSTRACTThe pneumococcal capsule is indispensable for pathogenesis in systemic infections; however, many pneumococcal diseases, including conjunctivitis, otitis media, and some systemic infections in immunocompromised patients, are caused by nonencapsulated Streptococcus pneumoniae (NESp). Null capsule clade 1 (NCC1), found in group 2 NESp, expresses pneumococcal surface protein K (PspK) and is becoming prevalent among pneumococcal organisms owing to the widespread use of pneumococcal conjugate vaccines. Despite its clinical importance, the molecular mechanisms underlying the prevalence of NCC1 have not been fully elucidated. Here, we investigated the role of the R3 domain of PspK in the epithelial cell adherence of NCC1. We found that the R3 domain of PspK mediated NCC1 adherence via its direct interaction with the epithelial surface protein annexin A2. Additionally, neutralization with purified recombinant PspK-R3 or rabbit anti-UD:R3 IgG inhibited binding of NESp to lung epithelial cells in vitro. Immunization with the ‘repeat’ domain of PspK-R3 or PspK-UD:R3 effectively elicited mucosal and systemic immune responses against PspK-R3 and provided protection against nasopharyngeal, lung, and middle ear colonization of NESp in mice. Additionally, we found that rabbit anti-UD:R3 IgG bound to PspC-R1 of the encapsulated TIGR4 strain and that UD:R3 immunization provided protection against nasopharyngeal and lung colonization of TIGR4 and deaths by TIGR4 and D39 in mice. Further studies using 68 pneumococcal clinical isolates showed that 79% of clinical isolates showed cross-reactivity to rabbit anti-UD:R3 IgG. About 87% of serotypes in the 13-valent pneumococcal conjugate vaccine (PCV) and 68% of non-vaccine serotypes were positive for cross-reactivity with rabbit anti-UD:R3 IgG. Thus, the R3 domain of PspK may be an effective vaccine candidate for both NESp and encapsulated Sp.

CCN3 Expression Marks a Sulfomucin-nonproducing Unique Subset of Colonic Goblet Cells in Mice.

Intestinal goblet cells are characterized by their unique morphology and specialized function to secrete mucins. Although it is known that they are a heterogeneous population of cells, there have been few studies that relate the expression of a particular gene with functionally distinct subpopulations of intestinal goblet cells. Here we show that CCN3, a gene encoding a member of the CCN family proteins, is induced by inhibition of Notch signaling in colonic epithelial cells and expressed in goblet cells in mice. We demonstrate that CCN3 expression is confined to a subpopulation of goblet cells in the lower crypt of the proximal and middle colon. In addition, CCN3+ cells in the colon correlate well with the cells that are positive for alcian blue (AB) staining but negative for high-iron diamine (HID) staining in histology. We also show that CCN3+ cells, which are absent in the normal distal colon, transiently and ectopically emerge in regenerating crypts during the repair phase of DSS-induced colitis model. Our study thus suggests that CCN3 labels a unique subpopulation of sulfomucin-nonproducing colonic goblet cells that function in both normal and diseased colonic epithelia.

The effects of inulin, dried Jerusalem artichoke tuber and a multispecies probiotic preparation on microbiota ecology and immune status of the large intestine in young pigs

ABSTRACTThe study aimed at determining the effect of two types of prebiotics and a multispecies probiotic on microbiota activity and composition, as well as mucosal immunity in the large intestine of young pigs. In total 48 piglets were divided into 6 groups (n = 8), which received from day 10 of life probiotic-unsupplemented (PU) or probiotic-supplemented (PS) diets. Probiotics were added at 0.5 g/kg diet and contained: Lactococcus lactis, Carnobacterium divergens, Lactobacillus casei, Lactobacillus plantarum and Saccharomyces cerevisiae. The PU and PS diets were formulated without prebiotic addition (control) or with addition of 2% of inulin from chicory root (IN) or 4% of dried Jerusalem artichoke tubers (DJA). After 40 days of feeding, digesta and tissue samples were taken from the caecum and three sections of the colon for analyses of microbiota activity and composition, secretory immunoglobulin A (sIgA) and intraepithelial lymphocytes (IEL). IN diets decreased the caecal digesta pH and β-glucosidase activity but increased propionic, valeric and total short chain fatty acid (SCFA) concentrations compared to control diets. Feeding DJA diets increased caecal valeric acid level, decreased the concentration of isoacids in the colon, reduced β-glucosidase and β-glucuronidase activity in the middle colon and increased Bifidobacterium spp. populations in the proximal and distal colon. PS diets increased the caecal acetic acid and total SCFA level, and Clostridium spp. populations in the distal colon. Neither probiotic nor prebiotics affected sIgA level or IEL number in the large intestine. In conclusion, DJA modified the microbiota ecology in the large intestine of young pigs to a greater extent than IN and the applied probiotic did not enhance effects of prebiotics.

Desacetyl bisacodyl-induced epithelial Cl(-) secretion in rat colon and rectum.

The purpose of this study was to clarify the mode of desacetyl bisacodyl (DAB)-induced secretory action in intestinal tissues using an Ussing chamber assay. DAB is the active metabolite of the laxative bisacodyl. In mucosal-submucosal preparations, mucosal application of DAB induced a transient decrease followed by subsequent increases in short-circuit current and tissue conductance in a concentration-dependent manner. DAB-induced responses occurred from the middle colon to the rectal segment but not in the proximal colon. Moreover, these responses were not observed under chloride (Cl(-))-free conditions or in the presence of DAB on the serosal side of the mucosalsubmucosal specimens. Treatment with tetrodotoxin had no effect on the DAB-induced responses; however, mucosal treatment with a COX inhibitor piroxicam resulted in the elimination of responses. These results suggest that DAB may contribute to the laxative action by inducing Cl(-) secretion which is associated with the COX signaling pathway. This study also demonstrated that the DAB target molecule is present on the mucosal side from the middle colon to the rectal segment.

Efficacy of a novel antimicrobial peptide against periodontal pathogens in both planktonic and polymicrobial biofilm states

Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis represent the early, middle and late colonizers of the bacterial accretion in dental plaque biofilms. These sessile communities constitute a protected mode of growth that promotes survival in a hostile environment. This study describes a novel and unrecognized role for a synthetic cationic antimicrobial peptide, Nal-P-113, which inhibits and kills periodontal bacteria in planktonic state, inhibits the formation of biofilms and eradicates polymicrobial biofilms. Nal-P-113 is also stable in saliva, serum and saline solution. At a concentration less than 320μg/mL which is harmless to normal oral cells, Nal-P-113 can kill bacteria in planktonic state. At a concentration of antimicrobial peptide Nal-P-113 (1280μg/mL) which only causes slight damages to normal oral cells is needed to kill bacteria in biofilm state. It is worth mentioning that this concentration of Nal-P-113 is harmless to rat oral mucosa compared to chlorhexidine. The mechanism of Nal-P-113 inhibiting and killing periodontal bacteria might rely on the abilities to permeabilize and/or to form pores within the cytoplasmic membranes, thus causes the death of bacteria. Here, we provided a novel and stable antimicrobial peptide with very low mammalian cytotoxicity, which can inhibit and kill periodontal bacteria in both planktonic and polymicrobial biofilm states. Statement of SignificanceNal-P-113 is a potent antimicrobial peptide with strong antimicrobial ability, improved deficiency compared with other antibacterial peptides, and remains stable in phosphate buffered saline, saliva, brain-heart infusion medium and bovine calf serum. Nal-P-113 exhibits a broad spectrum of bacteriocidal activity with excellent eradicating capability on oral pathogens and the respective biofilms. In this study, we used propidium iodide staining, scanning electron microscopy and transmission electron microscopy to confirm that Nal-P-113 can perforate plasmalemma thereby resulting in the death of oral pathogens and disintegrate the respective biofilms. Nal-P-113 also showed effective anti-plaque biofilms and cytotoxicity in the rat periodontitis model. No adverse effects can be observed on the gingivomucosa tissue. In short, the antimicrobial peptide Nal-P-113 presented to be an effective yet have low mammalian cytotoxicity agent with potential application in the clinic. This study provides a proof of concept in applying antimicrobial peptides in the clinical perspective.

Effects of flavone on the contractile activity of the circular smooth muscle of the rabbit middle colon in vitro

The circular smooth muscles of the middle colon of the rabbit generate giant contractions of high amplitude and low frequency. Flavone, at various concentrations, reduces the giant contractions and the tonic contraction induced by 10µM carbachol and 80mM KCl. The contractions induced by dequalinium and tetraethylammonium are reduced by flavone (30µM). At 100µM, flavone decreases the contraction induced by 100µM methylene blue and 1mM orthovanadate. These results suggest that flavone inhibit the giant contractions by (1) inhibition of voltage-dependent Ca2+ channels, (2) activation of guanyl cyclase, (3) opening of K+ channels and (4) inhibition of tyrosines kinases.

Intracolonic Administration of the TRPA1 Agonist Allyl Isothiocyanate Stimulates Colonic Motility and Defecation in Conscious Dogs

BackgroundThe aim of the present study was to investigate the effects of the intracolonic transient receptor potential (TRP) A1 agonist allyl isothiocyanate (AITC) on colonic motility and defecation. MethodsThe effects of AITC administered into the proximal colonic lumen on colonic motility and defecation were studied in neurally intact dogs equipped with strain-gauge force transducers on the colon, with or without various antagonists. Effects of intracolonic AITC were also studied in dogs with either transection/re-anastomosis (T/R) between the proximal and middle colon and complete extrinsic denervation of an ileocolonic segment. ResultsAITC increased colonic motility and induced giant migrating contractions (GMCs) with defecations in 75 % of experiments in neurally intact dogs. These effects were inhibited by atropine, hexamethonium, ondansetron, and HC-030031 but unaltered by capsazepine. In dogs with T/R, the increase in colonic motility was inhibited in the middle-distal colon. In dogs with extrinsic denervation, the increase in colonic motility in the distal colon was decreased. ConclusionsIntracolonic AITC stimulates colonic motility and defecation via cholinergic, serotonergic, and TRPA1 pathways. Continuity of colonic enteric neurons plays an essential role in the intracolonic AITC-induced colonic motor response, while extrinsic nerves are important in occurrence and propagation of GMCs.

Defatted flaxseed meal prevents the appearance of aberrant crypt foci in the colon of mice increasing the gene expression of p53.

The goal of this study was to investigate the preventive effects of defatted flaxseed meal on the appearance of aberrant crypt foci (ACF) in mice treated with 1,2-dimethylhydrazine (DMH). ACF were induced by intraperitoneal administration of 20 mg/kg body weight of DMH for 8 weeks. The animals were divided into three treatments (n=8): AIN93M diet without fibers + DMH (C-); AIN93M diet with defatted flaxseed meal (LIN); and AIN93M diet with defatted flaxseed meal + DMH (LINCA), for 15 weeks. The technique RT-PCR was used to evaluate the expression of p16, p21, p53, cyclin D1, and cyclin E in the distal colon. In addition, flow cytometric analysis of CD4 and CD8 spleen cells, the quantification of short-chain fatty acids (SCFA) in stool, the quantification of Bifidobacterium spp., Clostridium spp. in feces. LIN and LINCA showed increased Bifidobacterium spp. compared with control (C-). In relation to the weight of the organs, the groups LIN and LINCA showed higher values for the liver and kidney compared with control (C-). Regarding ACF, the group LINCA presented fewer ACF in the middle and distal colon compared with control (C-). When we analyzed ACF with more than three crypts the group LIN and LINCA did not present ACF in the middle and distal segments. LINCA presented increased p53 gene expression. This finding suggests that defatted flaxseed meal reduces ACF by increasing the expression of p53 and increase Bifidobacterium spp.

Comparative analysis of different doses of polyethylene glycol electrolyte solution for colonoscopy preparation

Objective To compare the efficacy of bowel-cleansing, patients′ compliance, tolerability and side effects of different doses of polyethylene glycol(PEG) electrolyte solution for colonoscopy preparation. Methods Single-blind prospective randomized trial was performed. A total of 100 inpatients undergoing elective colonoscopy were randomized into three groups to receive 4 L PEG(n=35), 2 L PEG(n=31) or 2+ 1 L PEG(n=34), respectively, on the day of colonoscopy from May to July 2014. Bowel-cleansing efficacy was separately assessed with the Ottawa Scale for the right, middle, and left colon. Total score was obtained by adding the scores for individual evaluation of the three colon segments with the score of overall fluid in the entire colon. All patients filled in a questionnaire and were interviewed about their compliance to the assigned bowel preparation, tolerability, and side effects. Results Patients who did not complete the colonoscopy were excluded. A total of 91 patients were included in the last analysis: 31 cases of 4 L group, 30 cases of 2 L group and 30 cases of 2+ 1 L group. The efficacy of bowel-cleansing of the three groups of patients according to the Ottawa Scale were similar(P>0.05), but the excellent and good rate of cleansing quality of the right colon was higher in 4 L group than in 2 L group(P<0.05). Compared with 4 L group and 2+ 1 L group, patients in the 2 L group had higher compliance and tolerability, as well as lower rate of side effects(P<0.05). Conclusion The efficacy and safety of taking 2 L polyethylene glycol electrolyte solution in bowel-cleansing on the day of colonoscopy is good and suitable for use. Taking 4 L polyethylene glycol electrolyte solution for bowel preparation on the day of colonoscopy is more suitable for patients who are suspected highly with lesions of the right colon. Key words: Polyethylene glycols; Electrolytes; Colonoscopy; Bowel preparation

A YadA-like autotransporter, Hag1 in Veillonella atypica is a multivalent hemagglutinin involved in adherence to oral streptococci, Porphyromonas gingivalis, and human oral buccal cells.

Dental biofilm development is a sequential process, and adherence between microbes and the salivary pellicle (adhesion) as well as among different microbes (co-adhesion or coaggregation) plays a critical role in building a biofilm community. The Veillonella species are among the most predominant species in the oral cavity and coaggregate with many initial, early, middle, and late colonizers. Similar to oral fusobacteria, they are also considered bridging species in biofilm development. However, the mechanism of this ability has yet to be reported, due to the previous lack of a genetic transformation system in the entire genus. In this study, we used our recently discovered transformable Veillonella strain, Veillonella atypica OK5, to probe the mechanism of coaggregation between Veillonella species and other oral bacteria. By insertional inactivation of all eight putative hemagglutinin genes, we identified one gene, hag1, which is involved in V.atypica coaggregation with the initial colonizers Streptococcus gordonii, Streptococcus oralis and Streptococcus cristatus, and the periodontal pathogen Porphyromonas gingivalis. The hag1 mutant also abolished adherence to human buccal cells. Inhibition assays using various chemical or physiological treatments suggest different mechanisms being involved in coaggregation with different partners. The entire hag1 gene was sequenced and shown to be the largest known bacterial hemagglutinin gene.

Expression and significance of aberrant crypt foci in rat colon cancer model

Objective To observe the development of aberrant crypt foci(ACF)in Wistar rat colon cancer model and to evaluate the correlation between ACF and tumor. Methods Sixty adult Wistar rats were randomly divided into 2 groups. Thirty Wistar rats in group A were subjected to the subcutaneous injection of 1,2- dimethylhydrazine(DMH)(20 mg/kg, once every week for 18 weeks), and those in group B were intraperitoneally injected with physiological saline for one week as the normal control group. The rats in groups A and B group were killed at 6th, 12th and 18th week respectively, and served as three subgroups. The colon tissues subject to methylene blue staining were observed under a microscope. Results ACF were distributed in the middle and distal colon(mostly 50%-80% of the cecum), and 12 tumors were seen. Four tumors were poorly differentiated mucinous adenocarcinoma, and located in the proximal colon(10%-20% of the cecum). In the rest 8 tumors, three were adenoma and 5 highly differentiated adenocarcinoma, and located in 50%-80% of the distal colon. The number of ACF in the colorectum could significantly influence the incidence of colorectal cancer. In group A of rats with ACF in colorectal, the pathological examination showed that the incidence of colonic lesions was 46.67%(14/30)and that of rectal cancer was 16.67%(5/30) respectively, which was significantly higher than in the rats without ACR odds ratio(OR)[95% confidence interval(CI)]: 13.352(5.529-32.581)and 6.582(1.374-17.494),P< 0.05]. Conclusion The number of ACF in the colorectum has significant influence on the development of colorectal cancer. Key words: Aberrant crypt foci; Colorectal cancer; Expression

Differential expression of motilin receptor in various parts of gastrointestinal tract in dogs.

Objectives. The presence of motilin receptor in the GI tract of different animal species has been verified. However, the quantitation of motilin receptor expression in different regions of the GI tract remains unclear. The aim of this study was to investigate the expression of motilin receptor in the GI tract and semiquantitatively compare the expression difference in different GI regions in dogs. Methods. Antrum, duodenum, jejunum, ileum, proximal colon, middle colon, and distal colon were obtained from various parts of the GI tract of six sacrificed dogs. The distribution of motilin receptor was determined by immunohistochemistry. The expression levels of motilin receptor mRNA in different regions were measured by RT-PCR. Results. Motilin receptor was expressed throughout the GI tract in dogs. Multiple comparisons of the mean motilin receptor mRNA expression among various regions were significant (P < 0.05). Motilin receptor mRNA was extensively expressed in duodenum, followed by ileum, jejunum, proximal colon, antrum, middle colon, and distal colon. Immunohistochemistry revealed that motilin receptor immunoreactivity was observed only in the enteric nervous system. Conclusion. Motilin receptor is expressed differentially along the GI tract in dogs. The significantly high expression of motilin receptor mRNA is found in the duodenum.

Clinical application of hand-assisted laparoscopy in transverse colectomy for middle transverse colon cancer

Clinical application of hand-assisted laparoscopy in transverse colectomy for middle transverse colon cancer