Mucositis manifesting as diarrhoea is a common side effect of chemotherapy which remains poorly understood. It is one of a number of manifestations of alimentary mucositis, which affects the entire gastrointestinal tract. The exact number of patients that are affected by diarrhoea as a result of treatment is uncertain, although it is believed that approximately 10% of patients with advanced cancer will be afflicted. Despite advances in the understanding of oral and small intestinal mucositis over recent years, large intestinal mucositis, including diarrhoea, has not been well defined and the underlying mechanisms of the condition are yet to be established. The majority of the literature available concerning diarrhoea is based on clinical observations, with very little basic research existing. However, from the research conducted, it is likely that the intestinal microflora and mucins play a role in the development of chemotherapy-induced diarrhoea. This thesis will examine in detail what is known about the mechanisms of chemotherapy-induced diarrhoea (CID). Furthermore it will explore the potentially important relationship between intestinal microflora, the luminal environment and the subsequent development of chemotherapy-induced mucositis and diarrhoea. 5-Fluorouracil (5-FU) is a commonly used chemotherapy agent in clinical oncology practice. Two of its major side effects are mucositis and diarrhoea. The structure of mucins offers mucosal protection, and allows maintenance of intestinal flora by providing attachment sites and preventing bacterial overgrowth and/or penetration. Following treatment with 5-FU, we showed decreases in Clostridium spp., Lactobacillus spp. and Streptococcus spp., and an increase in Escherichia spp. in the jejunum. In the colon, 5-FU caused decreases in Enterococcus spp., Lactobacillus spp. and Streptococcus spp. Real time PCR of faecal samples showed decreasing trends in Lactobacillus spp. and Bacteroides spp., and an increasing trend in E. coli. Significant increases (p<0.05) were seen in Clostridium spp. and Staphylococcus spp. at 24 h. Goblet cell numbers decreased significantly in the jejunum from 24-72 h, with a significant increase in the percentage of cavitated goblet cells, suggesting 5-FU treatment causes significant changes in intestinal flora and mucin secretion in rats. These changes could result in systemic effects, and in particular may contribute to the development of chemotherapy-induced mucositis. Irinotecan causes cholinergic and delayed onset diarrhoea in patients, in which β-glucuronidase produced by gut bacteria is thought to be involved. Diarrhoea was observed in treated rats, as expected, following irinotecan treatment. β-glucuronidase expression increased in the jejunum and colon. Faecal flora changed quantitatively after treatment also, with increases in E. coli, Staphylococcus spp., and Clostridium spp. (all β-glucuronidase producing), and decreases in Lactobacillus spp., Bifidobacterium spp. (both beneficial bacteria), and Bacteroides spp. (β-glucuronidase producing, major component of intestinal flora), suggesting that irinotecan-induced diarrhoea may be caused by an increase in β-glucuronidase producing bacteria. However, the increase in bacteria may also be caused by irinotecan, further exaggerating the toxicity of the drug, and emphasising the need for these specific bacteria to be therapeutically targeted for successful treatment regimens to be accomplished. Mucus production appears to be increased after irinotecan treatment, which may contribute to the development of diarrhoea. Goblet cells were demonstrated to decrease significantly after irinotecan treatment. However, mucin secretion increased. Mucin expression changed significantly after treatment. Muc2 and Muc4 decreased significantly in the villi of the jejunum after treatment, Muc2 and Muc4 decreased significantly in the crypts. Muc2 decreased significantly in the colon. This indicates that irinotecan causes an increase in mucin secretion and a net decrease in mucin-producing goblet cells, and the expression of Muc2 and Muc4 in the gastrointestinal tract is altered following treatment. Increased mucin secretion is likely to be related to altered mucin expression, and may contribute to chemotherapy-induced diarrhoea. To determine if the changes to the intestinal microflora caused by chemotherapy could be translated to the clinic, a pilot clinical study was carried out. Sixteen patients experiencing CID were recruited to the study with two control subjects. A large proportion of patients (75%) demonstrated a reduced anaerobic component of their faecal microflora. A reduced diversity of species was also observed in patients. The majority of patients exhibited decreases in Clostridium spp., Lactobacillus spp. and Bifidobacterium spp., whilst all patients exhibited decreases in Bacteroides spp. and Enterococcus spp. Patients receiving antibiotics did not exhibit any marked differences to patients not receiving antibiotics. This indicates that the results observed in the animal studies are clinically relevant, and further research into this area should be undertaken. CID is associated with marked changes in the intestinal microflora. These changes may result in diminished bacterial functions within the gut, altering gut function and initiating intestinal damage, resulting in the onset of diarrhoea. In conclusion, there is clear evidence demonstrating chemotherapy treatment results in changes to the intestinal microflora and mucin secretion, which may be responsible in part for the development of severe mucositis and diarrhoea. Irinotecan toxicity may be compounded by the increase in β-glucuronidase producing bacteria. The intestinal flora of cancer patients experiencing CID is also noticeably different to that of healthy subjects. Irinotecan causes changes to mucin secretion, and the specific expression of Muc2, Muc4 and Klf4, suggesting that secretory control by the enteric nervous system may also be affected by chemotherapy. This research has extended the understanding of chemotherapy-induced mucositis and diarrhoea, complex side effects of chemotherapy. However, new areas for future research have also been identified. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352119 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009

Mucositis manifesting as diarrhoea is a common side effect of chemotherapy which remains poorly understood. It is one of a number of manifestations of alimentary mucositis, which affects the entire gastrointestinal tract. The exact number of patients that are affected by diarrhoea as a result of treatment is uncertain, although it is believed that approximately 10% of patients with advanced cancer will be afflicted. Despite advances in the understanding of oral and small intestinal mucositis over recent years, large intestinal mucositis, including diarrhoea, has not been well defined and the underlying mechanisms of the condition are yet to be established. The majority of the literature available concerning diarrhoea is based on clinical observations, with very little basic research existing. However, from the research conducted, it is likely that the intestinal microflora and mucins play a role in the development of chemotherapy-induced diarrhoea. This thesis will examine in detail what is known about the mechanisms of chemotherapy-induced diarrhoea (CID). Furthermore it will explore the potentially important relationship between intestinal microflora, the luminal environment and the subsequent development of chemotherapy-induced mucositis and diarrhoea. 5-Fluorouracil (5-FU) is a commonly used chemotherapy agent in clinical oncology practice. Two of its major side effects are mucositis and diarrhoea. The structure of mucins offers mucosal protection, and allows maintenance of intestinal flora by providing attachment sites and preventing bacterial overgrowth and/or penetration. Following treatment with 5-FU, we showed decreases in Clostridium spp., Lactobacillus spp. and Streptococcus spp., and an increase in Escherichia spp. in the jejunum. In the colon, 5-FU caused decreases in Enterococcus spp., Lactobacillus spp. and Streptococcus spp. Real time PCR of faecal samples showed decreasing trends in Lactobacillus spp. and Bacteroides spp., and an increasing trend in E. coli. Significant increases (p<0.05) were seen in Clostridium spp. and Staphylococcus spp. at 24 h. Goblet cell numbers decreased significantly in the jejunum from 24-72 h, with a significant increase in the percentage of cavitated goblet cells, suggesting 5-FU treatment causes significant changes in intestinal flora and mucin secretion in rats. These changes could result in systemic effects, and in particular may contribute to the development of chemotherapy-induced mucositis. Irinotecan causes cholinergic and delayed onset diarrhoea in patients, in which β-glucuronidase produced by gut bacteria is thought to be involved. Diarrhoea was observed in treated rats, as expected, following irinotecan treatment. β-glucuronidase expression increased in the jejunum and colon. Faecal flora changed quantitatively after treatment also, with increases in E. coli, Staphylococcus spp., and Clostridium spp. (all β-glucuronidase producing), and decreases in Lactobacillus spp., Bifidobacterium spp. (both beneficial bacteria), and Bacteroides spp. (β-glucuronidase producing, major component of intestinal flora), suggesting that irinotecan-induced diarrhoea may be caused by an increase in β-glucuronidase producing bacteria. However, the increase in bacteria may also be caused by irinotecan, further exaggerating the toxicity of the drug, and emphasising the need for these specific bacteria to be therapeutically targeted for successful treatment regimens to be accomplished. Mucus production appears to be increased after irinotecan treatment, which may contribute to the development of diarrhoea. Goblet cells were demonstrated to decrease significantly after irinotecan treatment. However, mucin secretion increased. Mucin expression changed significantly after treatment. Muc2 and Muc4 decreased significantly in the villi of the jejunum after treatment, Muc2 and Muc4 decreased significantly in the crypts. Muc2 decreased significantly in the colon. This indicates that irinotecan causes an increase in mucin secretion and a net decrease in mucin-producing goblet cells, and the expression of Muc2 and Muc4 in the gastrointestinal tract is altered following treatment. Increased mucin secretion is likely to be related to altered mucin expression, and may contribute to chemotherapy-induced diarrhoea. To determine if the changes to the intestinal microflora caused by chemotherapy could be translated to the clinic, a pilot clinical study was carried out. Sixteen patients experiencing CID were recruited to the study with two control subjects. A large proportion of patients (75%) demonstrated a reduced anaerobic component of their faecal microflora. A reduced diversity of species was also observed in patients. The majority of patients exhibited decreases in Clostridium spp., Lactobacillus spp. and Bifidobacterium spp., whilst all patients exhibited decreases in Bacteroides spp. and Enterococcus spp. Patients receiving antibiotics did not exhibit any marked differences to patients not receiving antibiotics. This indicates that the results observed in the animal studies are clinically relevant, and further research into this area should be undertaken. CID is associated with marked changes in the intestinal microflora. These changes may result in diminished bacterial functions within the gut, altering gut function and initiating intestinal damage, resulting in the onset of diarrhoea. In conclusion, there is clear evidence demonstrating chemotherapy treatment results in changes to the intestinal microflora and mucin secretion, which may be responsible in part for the development of severe mucositis and diarrhoea. Irinotecan toxicity may be compounded by the increase in β-glucuronidase producing bacteria. The intestinal flora of cancer patients experiencing CID is also noticeably different to that of healthy subjects. Irinotecan causes changes to mucin secretion, and the specific expression of Muc2, Muc4 and Klf4, suggesting that secretory control by the enteric nervous system may also be affected by chemotherapy. This research has extended the understanding of chemotherapy-induced mucositis and diarrhoea, complex side effects of chemotherapy. However, new areas for future research have also been identified. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352119 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009

This thesis aims to assess the human health impact of exposure to estrogenic compounds from the diet. A multi-disciplinary approach is taken to address various aspects of this issue. An introduction to xenoestrogens, including international research priorities, wildlife and human health effects, mechanisms of action, structure activity relationships and additivity of estrogenic effects is provided as background information. An assessment of exposure to a range of naturally occurring and synthetic estrogenic compounds found in food is derived in Chapter 2. The assessment combines new and existing data on food concentration, food consumption and serum levels for each xenoestrogen. Exposure is combined with relative estrogenic potency data from published bioassasy data to estimate risk relative to normal circulating levels of estradiol. Assuming additivity of xenoestrogens, for an average New Zealand male and for post-menopausal women, xenoestrogens in the diet contribute an additional 12-90% of estrogenicity above normal circulating levels. For a pre-menopausal female, the contribution from the diet represents in the order of an additional 2%. The level of exposure determined in this thesis would seem to be of pharmacological relevance, especially for men with low levels of estrogen and for post-menopausal women. Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. A survey of the BPA content of a range of 80 canned foods available to the New Zealand consumer was undertaken and the results used in the exposure and risk assessments. BPA was detected in all foods analysed except soft drinks, at concentrations ranging from <10-29 µg/kg, except for individual samples of tuna, corned beef and coconut cream that were 109, 98 and 191 µg/kg respectively. None, of over 4000 individual exposure scenarios, exceeded the temporary Tolerable Daily Intake (TDI) of 10 µg/kg body weight per day set by the Scientific Committee on Food in 2002. Intestinal microflora influence the bioavailability of the naturally occurring xenoestrogens genistein and daidzein that contribute significantly to total estrogenicity from the diet. The degradation of genistein and daidzein by the faecal microfloral of 5 human subjects was variable and unpredictable between individuals and within an individual. These findings have important implications for the promotion and prescription of soy foods and supplements for disease prevention and health benefits. The "yeast assay" is one of a number of methods available to measure estrogenicity. This assay was established and validated. In utero exposure to estrogenic compounds at critical periods of sexual differentiation and endocrine development may imprint for health effects observed later in life. Placental transfer of estrogenicity, from 17β-estradiol was studied using the human placental perfusion model and the yeast assay. The placenta provides a protective barrier to the transfer of estrogenicity. Experiments with genistein showed that 5-15% placental transfer occurred, suggesting that in utero exposure might be in the order of 10% of maternal exposure. The thesis concludes with consideration of a genomic approach to substantiate, or refute, the mechanistic link between exposure to xenoestrogens and claimed human health effect. Such an approach offers exciting opportunity to clarify the mode of action of the synthetic versus the naturally occurring xenoestrogens, to confirm or dispute additivity of effect that is an important premise of the exposure assessment, to identify key genes involved in the many possible health effects and thence risk to the individual from dietary exposure to xenoestrogens.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Dominika Sobolová Supervisor: Assoc. Prof. Přemysl Mladěnka, Pharm.D., Ph.D. Title of diploma thesis: Pharmacokinetics of flavanols This work is focusing on summarizing available information about the fate of flavanols in the organism. It is necessary to know the pharmacokinetics to explain their biological effects. In contrast to other flavonoids, they occur in the form of aglycones in plant foods. Galoylation, polymerization and optical isomerism have an important influence on the pharmacokinetics. Partial absorption of monomers begins in the small intestine after oral ingestion. In addition to the liver, the extensive metabolic changes take place even in the enterocytes. The resulting metabolites enter the circulation or they are effluxed back into the intestinal lumen, especially in the case of (epi)catechin sulfates. Epicatechin and catechin are present almost exclusively as glucuronides, sulfates or methylated compounds in the plasma. On the contrary, free unconjugated forms prevail within the gallates. The extent of their absorption is lower. They are excreted via biliary excretion, while other catechins are quickly eliminated by the kidneys in urine. The bioavailability of the parent...

The microbial populations in the gastrointestinal tracts of poultry play an important role in normal digestive processes and in maintaining animal health. The purpose of this study was to evaluate the effects of probiotics, prebiotics and synbiotics on the growth parameters, gut ecosystem, histology and immune function. In this study, four experiments one in vitro and three in vivo were conducted using specific pathogen free (SPF) and Hubbard broiler chickens. The first experiment was designed to determine the influence of inulin as an effective prebiotic on lactic acid bacteria (LAB) strains, and to screen LAB for selection as a source of chicken probiotic. Eight strains of LAB were isolated from chicken caeca and three strains from the Plymouth University culture collection were screened for potential probiotic properties for growth in inulin from Jerusalem artichoke (Helianthus tuberosus) and commercial inulin (Frutafit® HD, Netherlands). Lactobacillus animalis JCM 8692 strain isolated from chicken caeca showed the highest auto-aggregation and co-aggregation ability, resistance to acidity and bile salts, strong suppression of pathogens and ability to adhere to epithelial cells compared with other isolated strains. The second experiment was conducted to investigate the influence of commercial inulin and Jerusalem artichoke tubers as prebiotic supplementation on the diversity of the caecal microflora, jejunum histology and immune organ of SPF chickens. This investigation has found that inulin which was extracted from JA had a similar result when compared with commercial inulin and could be a suitable candidate for an inulin source in broiler diets. The third experiment was conducted to investigate the influence of Bactocell® (PRO1) and Lb. animalis (PRO2) as probiotic supplements on broiler chickens. EPEF was significantly increased in probiotic1 and probiotic2 compared with control (311.03, 309.87 and 260.06) respectively. Both types of probiotics supported the growth of chicks healthy and could be a suitable candidate as a source of probiotic in broiler diet. The fourth experiment was conducted to investigate the influence of dietary supplementation of a probiotic (Lb. animalis), a prebiotic JA tuber and a combination of both (Synbiotic) in broiler chickens. Growth performance was improved in all additive supplementation compared with the control group. EPEF was increased in probiotic, prebiotic and synbiotic compared with control (290.8±11.8, 300.9±3.86, 322.1±7.09 and 262.3±5.94) respectively. Beneficial bacteria in the guts of chicks fed probiotic, prebiotic and synbiotic was increased compared with chicks fed control diet. The diversity of microbial population in the gastrointestinal tract of chickens improved due to additives. The intestinal villus lengths and microvilli density was improved in all additives supplementation in comparison with control. Overall, it was concluded that probiotic, prebiotic and synbiotics can positively affect production performance and can improve the gut health.

The house fly, Musca domestica can transmit human pathogens including Escherichia coli O157:H7 through regurgitation of ingested bacteria from the crop which is a foregut organ of house fly and stores the excess ingested nutrients. Interactions between the ingested bacteria and the crop have a direct influence on bacteria persistence, survival and ultimately fly vector competence. In this research, in situ crop vessel assay was developed to investigate bacterial growth within fly crops up to 48 hours post-ingestion. Flies were fasted for 12 h prior to feeding E. coli O157:H7 pEGFP and then fed bacteria with red food color which was added to confirm that flies had consumed the bacteria. After feeding, flies with red abdomens were aseptically dissected and crops were removed and maintained in sterile phosphate buffered saline in microtiter plates held at 32˚C. For each time point (0, 24 and 48 hours post-ingestion), five crops were homogenized individually using a tissue grinder and bacterial levels (CFU/crop) were monitored using plate counts. Confocal microscopy of intact crops was used to monitor biofilm development. There was no statistical difference in cell numbers (CFU/crop) over the 48 h incubation period. Microscopy showed that upon prolonged incubation, GFP-expressing E. coli within the crop produced biofilms. This method showed greater reproducibility in studying crop bacteria level than using a live fly feeding study. But this system was not recommended to study the interaction between bacteria and the crop of housefly.

The intestinal microflora is an extensive ecosystem of microorganisms that consists of symbiotic and pathogenic species. The microflora is responsible for many important functions in the human body. An unquestionable function is that it affects the health state of the host. The higher the biodiversity, the greater the benefit for the host. However, it is necessary to point out that this should not include a high diversity of pathogenic bacterial species. There are many "beneficial" species, especially from the Bifidobacterium and Lactobacillus families. In recent decades, the popularity of supplementing these "beneficial" species with various supplementary diets (e.g. probiotics) has been growing a lot. The presented diploma thesis deals with pilot studies of liquid commercial probiotic preparations from American companies Ascended Health (not available on the Czech market) and their effects on the human microbiome. The study involved 9 volunteers who provided 70 fecal samples before, during, and after use of the studied products. Two methods were used to determine the biodiversity of intestinal bacterial species. Both are based on the identification by bacterial DNA that encodes gene 16S rRNA. The first method uses PCR-DGGE technique and then identification by Sanger sequencing. The second method...

Commercial production of catfish is the leading aquaculture industry in the United States. Production in Mississippi, Louisiana, Alabama, and Arkansas representing 96% of the total catfish sales in the USA. In 2017, the USDA-FSIS added testing of generic Escherichia coli and Enterococcus to the sampling of Siluriformes. The incidence of Escherichia coli in fish and seafood has been associated with possible fecal matter contamination. However, this indicator bacteria could also be a part of the natural microflora of catfish ponds where processing plants collect hybrid catfish. Aerobes, Psychrotrophs, Coliforms, Escherichia coli, and Enterobacteriaceae counts among environmental, liquid and fish samples were tested every season and periodically during one day of operation. Generic Escherichia coli counts were greater in late Summer (P ≤ 0.05) for liquid samples (1 log CFU/g) . During the day, Escherichia coli appeared to be more recurrent in the afternoon at the skinning step (P ≤ 0.05).

No description available.

<p>We are all born germ-free. Soon after birth, microbes colonize our body’s surfaces, with the intestine housing the highest density of microbes on earth. Most of us remain blissfully unaware of this co-existence because inflammatory responses to the indigenous microbes are normally not triggered. Nonetheless, intestinal microbes are true educators of our immune system, which is exemplified by the immature immune system observed in germ-free animals. Accumulating evidence suggests that microbial exposure and/or composition impacts on immune regulation. As an example, isotype switch to immunoglobulin E (IgE) is normally very tightly regulated such that in healthy individuals and mice, serum levels are maintained at very low levels. In contrast, total serum IgE levels are elevated in germ-free mice, indicating that in the absence of microbes the regulatory pathway that maintains IgE at basal levels is disrupted. We hypothesize that in the absence of stimuli from the resident intestinal bacteria the immune system does not receive adequate educational signals. We showed that in germ-free mice class switch recombination (CSR) to IgE occurred at intestinal mucosal lymphoid sites a few weeks after birth. IgE levels then remained at elevated levels throughout life, even when intestinal bacteria were introduced after weaning. In the first part of this thesis, the mechanisms involved in this hygiene-induced IgE were investigateted. In a second part, the immunoregulatory role of commensal bacteria was extended to a model of autoimmunity.</p> <p>Collectively these results demonstrate a new dimension of the impact of intestinal symbionts on the immune system: they dictate baseline immune system regulation. Elucidating the mechanisms whereby microbes induce immunoregulatory pathways may give insights into the increasing prevalence of allergic- and autoimmune diseases.</p> / Doctor of Philosophy (PhD)