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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of a novel synbiotic targeted towards dogs

Tzortzis, George January 2003 (has links)
No description available.
2

Comparison of Microbial Quality of Commercial Probiotic Dietary Supplements

Pin-Wen Wang (7114058) 16 October 2019 (has links)
Probiotics provide positive health benefits and potentially can be used as a treatment and prevention for foodborne diseases. To provide such health effects, probiotic microbes must survive before and after consumption and successfully colonize the gastrointestinal tract in the human body and display antimicrobial properties. There is lacking of studies comparing survival and antimicrobial effects of probiotic bacteria in dietary supplements sold in USA. Therefore, 11 probiotic supplements were compared for their microbial quality. Viable counts of five supplements exceeded or closely met the counts listed on the label. Two supplements did not contain any live bacteria in one of the two tested lots and the remaining four had viable counts about 1-2 log lower than the claimed viable counts.<div><br></div><div>Nine products, containing viable counts in both tested lots, were further analyzed for their tolerance of simulated gastrointestinal (SGI) condition. The results show that the survival of probiotic bacteria in SGI condition depended on encapsulation and bacteria strains. Probiotic bacteria in the form of pearl exhibited better survival in simulated gastric juice than those in capsule form. Nine probiotic bacteria including seven <i>Lactobacillus</i> and two <i>Bacillus coagulans</i> were isolated from the nine products and identified. The nine isolates were resistance to 4 -7 out of eight tested antibiotics. Culture filtrates of the seven <i>Lactobacillus</i> isolates inhibited the growth of <i>Escherichia coli </i>O157:H7 and <i>Salmonella </i>Typhimurium but not <i>Listeria monocytogenes</i>. However, after adjusting pH to 6.5, none of the culture filtrates showed any growth inhibition effect. Five probiotic isolates, namely <i>L. acidophilus</i> La-5 and La-14,<i> L. plantarum</i> Lp-115 and 299v and <i>L. rhamnosus </i>GG, which had relatively higher viable counts after exposure to SGI were compared for their ability to adhere to HT-29 cells and to reduce adhesion of the three pathogens to HT-29 cells. After incubation for 1 h, <i>L. plantarum</i> Lp-115 displayed the highest mean adhesion ratio (25.9 ± 3.4 CFU/cell) whereas <i>L. acidophilus</i> La-5 and La-14 had the lowest two mean adhesion ratios which were 0.8±0.1 and 1.9±0.5 CFU/cell respectively. Adhesion reduction of the three pathogens on HT-29 cells varied depending on the probiotic strains, the pathogens, and the method for analysis (exclusion, competition, and displacement). Among the five,<i> L. plantarum </i>Lp-115 showed the strongest pathogen inhibition ability. It excluded >97% <i>E. coli</i> O157:H7 and >91% <i>S. Typhimurium </i>and displaced >96% <i>L. monocytogenes</i> on HT-29 cells. <i>Lactobacillus plantarum </i>v299G and <i>L. rhamnosus </i>GG also reduced adhesion of the three pathogens on HT-29 cells by the same mechanisms; however, the percentages of reduction were slightly lower. The <i>L. acidophilus </i>La-5 reduced > 93% <i>E. coli </i> O157:H7 on HT-29 cells by competition or displacement, and displaced about 94% L. monocytogenes on the cells. Nevertheless, it only reduced <28% <i> S. Typhimurium</i> on HT-29 cells by the three mechanisms. The<i> L. acidophilus</i> La-14 showed similar effects on adhesion reduction of the three pathogens on HT-29 cells. Overall, Nature’s way® Pearls was the best probiotic supplements since the form of pearl made the probiotic bacteria more resistant in SGI condition. Additionally, the <i> L. plantarum </i> Lp-115 in this supplement had the highest adhesion ratio and the best antimicrobial efficacy.</div>
3

Use of a probiotic for reduction of gastrointestinal oxalate absorption

Okombo, Joseph Otieno. January 2009 (has links)
Thesis (M.S.)--University of Wyoming, 2009. / Title from PDF title page (viewed on Apr. 15, 2010). Includes bibliographical references (p. 51-58).
4

The immunomodulatory effects of probiotics

Omakobia, Michael January 2015 (has links)
The development of childhood atopy is postulated to be influenced by perinatal microbial exposure. Inadequate numbers of probiotic organisms forming the intestinal microbiota, is an early pre-symptomatic feature linked to the expression of allergy. Perinatal probiotic supplementation is therefore hypothesized to contribute to the microbiota mediated immunomodulatory response determining immune hypo- responsiveness to allergens. Aims: This thesis examined the anti-allergy immunomodulatory effects of probiotic bacteria invitro in the context of the pathophysiology of atopy, as a preamble to perinatal probiotic supplementation. Methods: Cytokine responses were measured after umbilical cord blood mononuclear cells (CBMCs) were co-cultured in the presence of a consortium of probiotic organisms consisting of two strains of lactobacilli and two strains of bifidobacteria. Additionally pregnant women with a familial history of allergic disease from 36 weeks gestation and their infants to age 6 months, were supplemented with probiotics or a placebo daily. The immunomodulatory effects of probiotics on immune function in vivo was then analysed within the peripheral blood of the supplemented neonates. Results: CBMCs co-cultured in the presence of the probiotic consortium generated a dose dependent, monocyte mediated release of the pro-inflammatory cytokines TNF-a, IL- 12p70, IFN-y and the immunosuppressive cytokines IL-10 and TGF-pi. The consortium down regulated PH A and SEB induced IL-13 (a key allergy orchestrating cytokine) while potentiating IFN-y (a key Thl driving cytokine) responses from CBMCs. Interestingly in the probiotic supplemented group the cord blood eosinophil count was significantly reduced. Additionally the IL-12p70 concentrations in microbial stimulated venous blood at age 6 months was significantly elevated in comparison to the placebo supplemented group. Conclusion: The immunomodulatory effect of probiotic bacteria is marked by a capacity to promote a Thl orientation of the immune system. Probiotics administered during pregnancy and early infancy may therefore be effective in the prevention of Th2 mediated atopic disorder.
5

A novel organ culture model for polarized stimulation of human intestinal mucosa : probiotics and postbiotics in health and disease

Tsilingiri, Aikaterini January 2014 (has links)
As the use of probiotics and postbiotics is increasingly gaining ground in the past decade, the possibility of using bacterial strains with postbiotic activity to restore homeostasis in pathologic conditions such as IBD is extensively debated. However, clinical data as far as induction of remission is concerned has not been encouraging so far, while researchers observe that only a small number of treatments which seem promising on in vitro or mouse models translate to significant clinical benefit. This could mean that the models used so far to test potential treatments are not an accurate representation of the human intestine's rather complex micro-environment, and thus there is a need for the development of more relevant models. In this thesis, a novel organ culture model for polarized stimulation of intestinal mucosa is described. In the intestine, apical and basolateral challenge of the mucosal layer can elicit completely different results, and this is one of the issues addressed in this work. First of all, we show that it is possible to keep human intestinal mucosa in polarized culture for at least 24 hours, provided the explants are cultured in an atmosphere that is rich in oxygen. Polarized challenge is achieved by mechanical means, namely by attaching a cave plastic cylinder on the apical side of the mucosal layer, in order to confine the stimuli. We examine the impact of the cylinder and the surgical glue used to attach it on tissue morphology and survival, and show that there is no negative impact. Once optimized, this experimental set-up is used to challenge explants with pathogenic and probiotic bacteria alike and evaluate the immune response. On this model we are able to mimic a classical pathogen infection using a highly invasive Salmonella enterica serovar typhimurium strain, FB62. The response of the tissue to the pathogen was monitored by assessing the phenotype of explants after culture, while cytoine secretion profiles of the tissue were also studied. Salmonella challenge led to a damaged explant phenotype, upregulation of TNF-α and downregulation of IL-10. This response was abolished in the presence of an antiinflammatory postbiotic component, namely culture supernatant of the probiotic Lactobacillus paracasei. Moreover, as far as challenge with pathogens is concerned, we use this novel system to examine the mechanism of Shigella induced apoptosis of epithelial cells. Importantly, no animal models are available for the study of Shigella infection, as these 18 bacteria are poorly virulent in rodents. Thus, in an effort to study the involvement of Gadd45a in the apoptotic route triggered by Shigella on intestinal epitelial cells, HeLa cells, which are however a poor model for an intestinal pathogen were used. Gadd45a participates in the responses to a variety of DNA damaging agents and interacts with proteins such as Cdc2, PCNA and p21. In this work, the authors showed that after infection of HeLa cells with Shigella, Gadd45a is involved in the induction of the apoptotic process. The data was confirmed in a more relevant setting, by applying Shigella on human intestinal mucosa. Finally, we use the novel organ culture platform to test three different strains thought to exert probiotic actions. Surprisingly, we show that this is not the case, and the three strains can exert different activities even on healthy tissue. More specifically, Lactobacillus paracasei and Lactobacillus rhamnosus GG did not significantly alter the phenotype or cytokine secretion profiles of healthy explants, but challenge with Lactobacillus plantarum resulted in a detrimental effect. Of note, all three strains were detrimental for IBD explants when administered as live bacteria, even though one of the strains (L. paracasei) had previously been found to exert a prophylactic effect in a mouse model of colitis. On the contrary, we show that a potent postbiotic (L. paracasei culture supernatant) is able to ameliorate overt inflammation on both ulcerative colitis and Crohn's disease tissues as attested by cytokine secretion profiles of challenged explants. In conclusion, this work introduces a valid alternative system on which to study the interaction of various components (bacterial, pharmacological, and others) with the human intestinal mucosa.
6

Probiotics: Healthy Bacteria Used in Heart Surgery Patients

Lickteig, Crista January 2011 (has links)
Post-operative infections are of high concern and are a great risk to patients who have just had an open-heart surgical procedure. Exposing the human body to elements it's clearly not used to, by opening the chest to perform heart surgery, greatly increases a patient's risk of infection. Surgery is usually the last line of defense used by physicians. This is not only because the invasiveness of the procedure, but because of the heightened risk of infection for the patient. In the treatment of surgical patients, the possibility of infection and protocol for treatment must be taken into account. Patients who undergo open-heart procedures, such as CABG's, Valve Repair/Replacement, Aneurysms, and Aortic Root Repair/Replacement, often have compromised immune systems. A compromised immune system, exposure of the chest cavity during surgery, and length of hospital stay are all contributing factors to hospital acquired infections (HAI). Infections vary depending on the nature of the surgery, the institution, surgical technique, and also varies by patient. Pneumonia, sepsis, bacterial endocarditis, and mediastinitis are all potential concerns in patients who have undergone recent open-heart surgery. The recent societal push for a more holistic approach to medicine and an effort for treatments with fewer side effects have lead to increased research in the realm of probiotics. Probiotics are "good bacteria" that are thought to aid in the intestinal microbial balance. They also have been shown to improve gastrointestinal problems. By integrating the use of probiotics into the treatment of post cardiac surgery patients, we expect to see a decrease in gastrointestinal problems and infections. We also believe that this will improve patients' overall health. This preventative treatment will save the hospital millions of dollars in revenue that is spent on treating infections and will also increase hospital bed turnover.
7

En inventering av i vilken utsträckning lactobaciller används i vården på Akademiska sjukhuset

Eklöf, Ida, Björn, Sara January 2009 (has links)
<p>Syfte: Syftet med studien var att inventera lactobacillanvändandet i vården av patienter på Akademiska sjukhuset i Uppsala. Metod: Enkäter skickades ut till 67 vårdavdelningar på sjukhuset. Svarsfrekvens var 79 % och bortfallet 21 %.</p><p>Resultat: Huvudresultatet i studien är att en stor del (76 %) av avdelningarna vid Akademiska sjukhuset i Uppsala använder sig av lactobaciller i vården av patienter. Den mest frekvent använda produkten är Proviva saft/fruktsoppa (54 %). De samlade filprodukterna står tillsammans för 24 % av användandet. Den främsta indikationen varför lactobacillprodukter ges är vid antibiotikabehandling för att undvika relaterade magproblem. Nästa stora indikationsgrundande tillstånd är den generella användningen då man serverar exempelvis filprodukter på generell basis ("det enda som finns”).</p><p>Diskussion: Att användningen av Lactobaciller är så utbredd kan bland annat vara ett resultat av intensiv marknadsföring som tilltalat både vårdpersonal och patienter. Vid några av de adminsitreringsgrundande tillstånden som avdelningarna angett finns kliniska studier som kan tänkas ligga till grund för administration, men mycket av distributionen tycks ske utan evidens som grund.</p><p>Slutsats: Lactobaciller används i stor utsträckning i vården av patienter på Akademiska sjukhuset och vid många olika tillstånd, men med tonvikt på olika mag-tarm åkommor och främst vid antibiotikabehandling.</p>
8

En inventering av i vilken utsträckning lactobaciller används i vården på Akademiska sjukhuset

Eklöf, Ida, Björn, Sara January 2009 (has links)
Syfte: Syftet med studien var att inventera lactobacillanvändandet i vården av patienter på Akademiska sjukhuset i Uppsala. Metod: Enkäter skickades ut till 67 vårdavdelningar på sjukhuset. Svarsfrekvens var 79 % och bortfallet 21 %. Resultat: Huvudresultatet i studien är att en stor del (76 %) av avdelningarna vid Akademiska sjukhuset i Uppsala använder sig av lactobaciller i vården av patienter. Den mest frekvent använda produkten är Proviva saft/fruktsoppa (54 %). De samlade filprodukterna står tillsammans för 24 % av användandet. Den främsta indikationen varför lactobacillprodukter ges är vid antibiotikabehandling för att undvika relaterade magproblem. Nästa stora indikationsgrundande tillstånd är den generella användningen då man serverar exempelvis filprodukter på generell basis ("det enda som finns”). Diskussion: Att användningen av Lactobaciller är så utbredd kan bland annat vara ett resultat av intensiv marknadsföring som tilltalat både vårdpersonal och patienter. Vid några av de adminsitreringsgrundande tillstånden som avdelningarna angett finns kliniska studier som kan tänkas ligga till grund för administration, men mycket av distributionen tycks ske utan evidens som grund. Slutsats: Lactobaciller används i stor utsträckning i vården av patienter på Akademiska sjukhuset och vid många olika tillstånd, men med tonvikt på olika mag-tarm åkommor och främst vid antibiotikabehandling.
9

Modulation of atherosclerosis by probiotic bacteria VSL#3 and LGG in ApoE-/- mice

陳怡君, Chan, Yee-kwan January 2012 (has links)
Atherosclerosis is the major cause of cardiovascular diseases, which constitute the top ten leading causes of death worldwide. Atherosclerotic plaque development initiates from the inflamed endothelium under an atherogenic environment – chronic low grade inflammation, hypercholesterolemia, endotoxemia, etc. The principal cause of such inflammation has yet to be defined – with growing evidence that microbial stimulants like lipopolysaccharide (LPS) and peptidoglycan (PGN), which can activate toll-like receptors (TLRs) and nuclear factor-kappaB (NFκB) signaling might be the plausible origins. The gastrointestinal tract is suggested to be the major site for absorption and translocation of such stimulants, where gut microbiota have been associated with systemic inflammation and is essential in generating atherogenic substances. Since probiotics have the potential to induce systemic anti-inflammatory effects and fortify gut barrier to reduce bacterial translocation, evaluation of whether probiotics can help reduce atherogenesis was done by feeding the disease model, ApoE-/- mice with high fat diet alone, with telmisartan (1 or 5 mg/kg/day, positive controls) or with probiotics VSL#3 (2.8 x 1011 CFU/day) and/or Lactobacillus rhamnosus strain GG (LGG) (1x108 CFU/day), or the combination of which for 12 weeks. All treatments reduced lesion size significantly; with some treatments reduced plasma endotoxin, cholesterol and various proinflammatory biomarkers. The gut microbiota assessed with PCR-amplified 16S rRNA gene sequences using 454 pyrosequencing and thereafter correlation studies revealed that at least 20 bacterial families that were significantly altered by high fat diet in apolipoprotein E knockout (ApoE-/-)mice correlated with atherosclerotic plaque size and related biomarkers including cholesterol, adipocyte fatty acidbinding protein (A-FABP), etc. Probiotics showed potential in improving atherogenic environment by immunomodulation and induction or inhibition of growth of bacteria correlated with the atherosclerotic plaque and biomarkers. The atherosclerotic condition was also improved by telmisartan, which correlated with the altered gut microbiota. The newly identified atherosclerosis-related gut bacteria will require further exploration into their properties and mechanisms, which will eventually lead to the potential of developing probiotics for the treatment or prevention of atherosclerosis, and thus may be used as an affordable and non-invasive alternative that brings health benefits worldwide. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy
10

Immunomodulatory properties of probiotic bacteria

Fong, Long-yan, 方朗茵 January 2013 (has links)
Probiotics are living microorganisms, which when administered in adequate amounts confer a health benefit on the host. They have been reported to relieve acute diarrhoea, atopic dermatitis and irritable bowel syndrome in disease-specific animal studies and in human intervention trials. However, probiotics are regularly consumed by general healthy population with limited knowledge in the immunomodulation of probiotics of local and systemic immune responses in healthy experimental models. Serving as the first line of defense against microbial infections and the largest immunological organ in animal host, the epithelium lining the small and large intestine is supposed to be the first organ to encounter probiotics as probiotics are always orally taken. It is believed that probiotics regulate the local immunities in the gut, which acts as the pivot in modulating the systemic immune responses. Accordingly, it was hypothesized that probiotic bacteria can modulate both local and systemic immune responses in healthy population; and the immunomodulation of combination of probiotics is different from that of individual strains. Wildtype healthy C57BL/6 mice were fed with different probiotic strains − Lactobacillus rhamnosus GG (LGG), Lactobacillus rhamnosus LC705 (LC705), Bifidobacterium breve Bb99 (Bb99), Propionibacterium freudenreichii ssp. shermanii JS (PJS) or Escherichia coli Nissle 1917 (EcN), or mixture of probiotics − GGmix (LGG, LC705, Bb99 and PJS) and ECPJSmix (PJS and EcN), for three weeks. After that, intestine, liver, spleen and blood were investigated. Probiotics suppressed intestinal T helper (Th)17 immune response but enhanced systemic (hepatic and splenic) Th17 immune response, suggesting that immune homeostasis was maintained in healthy individuals. Mechanism of action of LGG was further studied in this project as LGG is the widely studied probiotics. It was hypothesized that LGG exerts immunomodulatory effects by bacteria cells and/or its derived soluble factors such as lactic acid. Immunomodulatory effects of LGG cells and their soluble factors on dendritic cells (DCs), macrophages and monocytes from healthy blood donors were investigated as antigen-presenting cells (APCs) are pivots of bridging innate and adaptive immunities. Cytokine secretion profile, expressions of toll-like receptors (TLRs) and activation-related receptors of the APCs were examined. Both LGG cells and their soluble factors promoted type 1-responsiveness while soluble factors promoted type 17-responsiveness as well. Yet, lactic acid seemed not to be the one which enhanced type 1 and type 17 immune responses in soluble factors. With better understanding on the immunomodulation of probiotics in healthy models, prophylactic efficacy of probiotics in preventing infections and diseases can be availed. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

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