Wang, Hui Chuan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 184-202). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

For the purpose of developing an effective therapeutic strategy for HSCR, the enteric neural crest stem cells were investigated firstly which were isolated from the E14.5 mouse embryonic gut, cultured as neurospheres and characterized by multiple immunofluorescence and reverse transcription-PCR, population doubling time, frequency of forming secondary neurospheres and limited dilution assay. In the differentiation culture medium, several types of cells were induced to form from the neurospheres derived from single cells. Hence the putative enteric neural crest stern cells, which were isolated from the embryonic mouse gut tube and cultured as neurospheres for many passages ex vivo with the demonstrated capacity of proliferation, self-renewal and differentiation, showed properties of stem cells. / Hirschsprung's disease (HSCR) is caused by the absence of the enteric neural crest-derived neurons at the distal region of the gut. Cell-based therapy using stem cells or progenitors gives the potential to supplement these missing enteric neurons in the gut. Enteric neural crest stem cells isolated from the human or rodent gut can give rise to neurons and glia after they are transplanted into the recipient guts of the mouse or rat. However, numbers of issues are unresolved about the basic biology of the enteric nervous system, the characteristics of the stem cells isolated from the enteric nervous system and the biological significance of these cells in prenatal and postnatal periods. In this study, the characteristics and therapeutic potential on HSCR of the enteric neural crest stem cells were explored. / In addition to the above, a recombination organotypic gut culture ex vivo showed that the colonization of enteric neural crest-derived cells in the recipient gut was influenced not only by the genotypes of enteric neural crest-derived cells themselves but also the microenvironment of the gut through which enteric neural crest-derived cells migrated. For instance, the developmental stage of the recipient gut and also the presence of endogenous enteric neural crest-derived cells along the migratory pathway of neural crest-derived cells both affected the extent of the migration and colonization of exogenous enteric neural crest-derived cells and stem cells. The gradual maturation and differentiation of the neighboring structures, such as the smooth muscle layer, during the time period of the enteric neural crest cells migration, might also suggest that these neighboring tissues may have a role in regulating the neural crest-derived cells migration. / In conclusion, enteric neural crest stem cells isolated from the embryonic mouse gut tube showed properties of stem cells, and had the potential to compensate missing enteric neural crest-derived cells both ex vivo and in vivo. However, the colonization of enteric neural crest-derived cells in the developing gut was affected cell-autonomously and also by the microenvironment of the gut and the presence of existing enteric neural crest-derived cells. / Their potential applications in the transplantation experiments were shown by transplantation of the neurospheres isolated to the gut tube maintained in an organotypic culture or to the descending colon of neonates at postnatal day 7. The development of the enteric neural crest stern cells from the neurospheres was found to be compatible to endogenous enteric neural crest-derived cells in the recipient gut as evidenced by the formation of interconnected cellular networks of donor stem cells and endogenous neural crest-derived cells. The enteric neural crest stem cells also possess the potential to compensate the loss of enteric neural crest-derived cells ex vivo and in vivo in recipient prenatal and postnatal guts. / Bao, Lihua. / Adviser: Wood Yee Chan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 208-228). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The Pacific Northwest is known for its once-abundant wild salmonid populations that have been in decline for more than 50 years due to habitat destruction and commercial overexploitation. To compensate, federal and state agencies annually release hundreds of thousands of hatchery-reared fish into the wild. However, accumulating data indicate that hatchery fish have lower fitness in natural environments, and that hatchery rearing negatively influences return rates of anadromous salmonids. Recently, mounting evidence revealed that the richness and diversity of intestinal microbial species influence host health. We examined the gut microbiota of pre-migratory hatchery-reared steelhead (Oncorhynchus mykiss) to assess microbial community diversity. The Cascade Mountains serve as an allopatric border between two distinct clades of steelhead that show significant differences in genomic and mitochondrial diversity. We identified differences in core microbiota of hatchery-reared fish that correlate with this divergent phylogeographic distribution. Steelhead sampled from hatcheries east of the Cascades had overall greater core gut microbiota diversity. These differences were found despite similarities in diet and rearing conditions. In addition to taxonomic variation across the geographic divide, we identified significant differences in metabolic pathways using PICRUSt gene prediction software. Our analysis revealed significant enrichment of genes associated with lipid metabolism in the gut microbiome of western fish. 8 of 19 individual lipid metabolism pathways were more prominent in western populations. Lipids are a vital nutritional component for teleost species involved in migration and subsequent return for spawning in natal environments. We hypothesize that the observed differences in lipid metabolism across this phylogenetic divide results from an increased ability of eastern Cascade (O. m. gairdneri) fish to utilize lipids taken in via the diet. This increased absorption and utilization would make lipids less available for the intestinal microbiota of the eastern fish, as evidenced by the lower abundance of lipid metabolism genes in the east. Our research utilizes information from the microbiome to understand the phenotypic implications occurring in segregated populations of hatchery-reared steelhead, further confirming elements of coevolution between an organism and its internal environment.

Calf scours are caused by a variety of infectious agents. Oral rehydration therapy solutions are formulated with the objective of correcting dehydration and acidosis. Currently, oral rehydraton therapy does not promote gut healing in diarrheic calves. However, investigators are examining the role of nutrition in promoting gut healing. Previous work has shown that the amino acid glutamine is important in nitrogen transport between tissues and is an indispensable nutrient for rapidly dividing cells such as lymphocytes, fibroblasts and enterocytes. Small intestinal epithelial cells depend mainly on glutamine, glucose, and ketone bodies for their energy under normal physiological conditions. The oxidative substrate preferred by large intestinal epithelial cells appears to be butyrate, followed by acetate, glutamine, and glucose. Research shows that glutamine supplementation increases intestinal protein synthesis. This may be one of the mechanisms by which glutamine exerts its protective effect on gut integrity and mucosal barrier function during critical illness. However, questions concerning the optimum dose and route by which glutamine is to be administered have yet to be addressed. A surgical model was developed to chronically study the nutrient concentration differences across the portal-drained viscera of preruminant calves. The experimental design consisted of a series of infusions conducted on four different study days in each calf. On the study days, 4 separate 1h infusions of acetate, glucose, glutamine, saline (control) were administered intravenously via the jugular vein at 200 mmol/L/h in a different order. Venous and arterial blood were collected over the last 15 min of each 1h infusion. Blood flow was also measured. Intestinal uptake in ìmol/kg^0.75/min was 0.3 ± 1.1 for glutamine and 1.9 ± 3.1 for glucose during saline infusion. During acetate, glucose, and saline infusions, glucose was a greater source of energy than glutamine for the intestine. However, during glutamine infusion, intestinal glutamine uptake (29.9 ± 11.2 ìmol/kg^0.75/min) increased significantly which was associated with a rise in ammonia production (7.0 ± 0.5 ìmol/kg^0.75min). A second experiment was designed to determine if glutamine uptake could be further stimulated either by longer term intravenous infusion or by chronic oral supplementation in neonatal calves. Intestinal metabolism was investigated by measuring nutrient uptake during three intravenous infusions of glutamine over a 5 h period after an overnight fast. Prior to the first infusion, calves diet consisted of milk only. Diet was supplemented with oral glutamine for the second and third infusions. Glutamine was administered via the jugular vein at a rate of 200 mmol/L/h. Venous and arterial blood was collected in duplicate every hour for 5 h. Blood flow was also measured. During glutamine infusion, there was an absolute increase in PDV uptake of glutamine associated with a significant production of ammonia. Feeding glutamine orally did not alter the PDV glutamine uptake. Glutamine infusion did not increase the intestinal uptake of essential amino acids. Neither chronic oral supplementation with glutamine, or infusion for periods longer than an hour, further increased intestinal glutamine uptake. Arterial leucine concentration and intestinal uptake declined during glutamine infusion suggesting that its supply became limiting. Thus glutamine supplementation may require the provision of a mixture of amino acids to be effective.

Thesis (M.Tech.: Biotechnology)- Dept. of Biotechnology, Durban University of Technology, 2007 xv, 127 leaves / The human gut microbiota play a major role in host health, and attempts are being made to manipulate the composition of the gut microbiota-increase the composition of bacterial groups, such as lactobacilli and bifidobacteria that are perceived as exerting health promoting properties. These bacteria defined as food supplements (probiotics) beneficially affect the host by improving the intestinal microbial balance, and have been used to change the composition of the colonic microbiota. However, such changes may be transient, and the implantation of exogenous bacteria therefore becomes limited. In contrast, prebiotics are naturally occurring carbohydrates that are classified as non-digestible oligosaccharides present in edible plants. These carbohydrates enter the colon as intact compounds, elicit systemic physiological functions and act as fermentable substrates for colonic microflora-influencing the species composition and metabolic characteristics of intestinal microflora providing important health attributes. Currently, a widely marketed prebiotic, inulin is extracted from plants of the family Asteraceae. There are many unexploited plants that are regularly consumed and that may have a prebiotic effect or can have very high levels of inulin which could make them commercially viable. In this study, we investigated prebiotic compounds, especially inulin from locally growing, non-commercialised leafy plants. The aqueous extracts of 22 plants from the families Asparagaceae, Alliaceae, Asteraceae, Solanaceae, Cucurbitaceae, Amaranthaceae, Acanthaceae, Polygonaceae, Portulaceae, Fabaceae, Chenopodiaceae, Pedaliaceae and Apiaceae from Kwa-Zulu Natal were investigated for a prebiotic effect using a modified batch-culture technique with Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus reuteri and Bifidobacterium longum, four common probiotics and the inulin content of the plants was determined using high performance liquid chromatography. Of the 22 plants studied, Solanum nigrum, Amaranthus spinosus, Amaranthus hybridus, Asystasia gangetica, Senna occidentalis, Cerathoteca triloba, Asparagus sprengeri, Tulbaghia violacea, Sonchus oleraceus and Taraxacum officinale exhibited a prebiotic effect. The prebiotic effect of the Taraxacum officinale, Sonchus oleraceus and Asparagus sprengeri extracts on L. lactis and L. reuteri was higher than or equivalent to inulin-a commercial prebiotic. In this study, Sonchus oleraceus exhibited the best prebiotic effect-was the only plant to stimulate all the probiotics including B. longum. Of all the plants analysed, Asparagus sprengeri tuber contained the highest amount of inulin (3.55%).

There is no abstract available for this thesis. / Department of Family and Consumer Sciences

Made available in DSpace on 2014-11-10T11:09:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-27Bitstream added on 2014-11-10T11:57:43Z : No. of bitstreams: 1 000783736.pdf: 2035792 bytes, checksum: 625352f737e5067d881064a582a375aa (MD5) / A epidemiologia das infecções por nematódeos gastrintestinais foi avaliada em ovinos criados em Botucatu - SP. A partir de abril de 2008 até março de 2011, dois cordeiros traçadores foram expostos à infecção natural por nematódeos gastrintestinais durante 28 dias consecutivos, ao pastejar junto com um rebanho de ovelhas. Haemonchus contortus apresentou as maiores intensidades de infecção com prevalência de 100%. Não houve influência significativa das estações do ano na intensidade de infecção por H. contortus. Trichostrongylus colubriformis também apresentou prevalência de 100% com a intensidade de infecção menor durante os meses de verão. No caso de T. colubriformis, houve correlação significativa entre as contagens de vermes x precipitação (r = -0,32; P < 0,05). Outras três espécies de nematódeos foram verificadas, no entanto, em pequenas quantidades, prevalências e intensidades de infecção: Oesophagostomum columbianum 28% (25,2), Cooperia curticei 7% (4,5) e Trichuris spp. 2 % (1). Contudo, as condições ambientais da área foram favoráveis durante todo o ano para a transmissão de H. contortus e T. colubriformis. Este fato explica parcialmente o fracasso de programas governamentais e privados realizados no intuito de promover a ovinocultura no Estado, devido a taxas elevadas de mortalidade e baixa produtividade causada pela verminose / The epidemiology of gastrointestinal nematode infections was evaluated in sheep raised in Botucatu – SP. Every month, from April 2008 until March 2011, two tracer lambs were exposed to natural infection with gastrointestinal nematodes for 28 consecutive days, while grazing together with a sheep flock. Haemonchus contortus presented the highest infection intensities with 100% prevalence. There was no significant influence of the seasons in H. contortus infection intensity. Trichostrongylus colubriformis also presented 100% prevalence with the lowest infection intensity during the summer months. In the case of T. colubriformis, there was significant correlation coefficient between worm counts x precipitation (r = -0.32; P < 0.05). Other three nematodes species were found in tracer lambs, however, in small numbers. Their prevalence and mean intensity of infection (in parenthesis) were the following: Oesophagostomum columbianum 28% (25.2), Cooperia curticei 7% (4.5) and Trichuris spp. 2% (1). In conclusion, the environmental conditions of the area were very favourable for H. contortus and T. colubriformis transmission all year round. These explain in part the failure of private and governmental programs to promote the sheep breeding activity in São Paulo State due to high sheep mortality rates and low productivity caused by gastrointestinal nematode infections

Orientador: Alessandro Francisco Talamini do Amarante / Banca: Raimundo de Souza Lopes / Banca: Fernanda Rosalinski Moraes / Resumo: A epidemiologia das infecções por nematódeos gastrintestinais foi avaliada em ovinos criados em Botucatu - SP. A partir de abril de 2008 até março de 2011, dois cordeiros traçadores foram expostos à infecção natural por nematódeos gastrintestinais durante 28 dias consecutivos, ao pastejar junto com um rebanho de ovelhas. Haemonchus contortus apresentou as maiores intensidades de infecção com prevalência de 100%. Não houve influência significativa das estações do ano na intensidade de infecção por H. contortus. Trichostrongylus colubriformis também apresentou prevalência de 100% com a intensidade de infecção menor durante os meses de verão. No caso de T. colubriformis, houve correlação significativa entre as contagens de vermes x precipitação (r = -0,32; P < 0,05). Outras três espécies de nematódeos foram verificadas, no entanto, em pequenas quantidades, prevalências e intensidades de infecção: Oesophagostomum columbianum 28% (25,2), Cooperia curticei 7% (4,5) e Trichuris spp. 2 % (1). Contudo, as condições ambientais da área foram favoráveis durante todo o ano para a transmissão de H. contortus e T. colubriformis. Este fato explica parcialmente o fracasso de programas governamentais e privados realizados no intuito de promover a ovinocultura no Estado, devido a taxas elevadas de mortalidade e baixa produtividade causada pela verminose / Abstract: The epidemiology of gastrointestinal nematode infections was evaluated in sheep raised in Botucatu - SP. Every month, from April 2008 until March 2011, two tracer lambs were exposed to natural infection with gastrointestinal nematodes for 28 consecutive days, while grazing together with a sheep flock. Haemonchus contortus presented the highest infection intensities with 100% prevalence. There was no significant influence of the seasons in H. contortus infection intensity. Trichostrongylus colubriformis also presented 100% prevalence with the lowest infection intensity during the summer months. In the case of T. colubriformis, there was significant correlation coefficient between worm counts x precipitation (r = -0.32; P < 0.05). Other three nematodes species were found in tracer lambs, however, in small numbers. Their prevalence and mean intensity of infection (in parenthesis) were the following: Oesophagostomum columbianum 28% (25.2), Cooperia curticei 7% (4.5) and Trichuris spp. 2% (1). In conclusion, the environmental conditions of the area were very favourable for H. contortus and T. colubriformis transmission all year round. These explain in part the failure of private and governmental programs to promote the sheep breeding activity in São Paulo State due to high sheep mortality rates and low productivity caused by gastrointestinal nematode infections / Mestre

The combinatorial code of cPcdh isoforms creates a diversified cell-surface molecular signature for cell-cell recognition in neural networks. This genetic architecture, combined with a regulated expression pattern and trans-homophilic binding properties, provides insights into cell specialization and signaling. Anomalies in cPcdhs, which include genetic mutations, epigenetic modifications, structural variations, and altered gene expression profiles, are associated with several neurological, neuropsychiatric, and systemic conditions, highlighting the importance of cPcdh investigations. This study focuses on the transcriptional regulation of the Pcdhα gene cluster. Each neuron displays a specific Pcdhα alternate exon repertoire, necessitating an understanding of the transcriptional dynamics. Using the SK-N-SH human neuroblastoma cell line and methodologies such as cRNA-seq and Start-Seq, these dynamics are examined. The application of CRISPR-Cas9 gene editing and a dCas9-VPR gain-of-function assay in the HEK293T cell line reveals the role of as-lncRNA and its interaction with DNA methylation within the Pcdhα gene cluster. This study identifies the role of noncoding as-lncRNA in RNA transcription and provides information on CTCF binding and Pcdhα promoter activation. The research also examines the gastrointestinal domain, as cPcdhs are linked to various diseases. Shifting focus from the canonical realm of the CNS, the research embarks on a preliminary yet pivotal exploration of the gastrointestinal domain. As cPcdhs intersect with a plethora of diseases, an incisive understanding of their expression could yield revelations into tissue susceptibilities with potential disease ramifications. Employing a novel single-domain antibody technique coupled with immunohistochemistry, the endeavor casts a precise lens into the gastrointestinal expression dynamics of Pcdhα and Pcdhγ. These insights not only fortify the understanding of cPcdh within neural structures but also beckon a deeper inquiry into their multifaceted biological roles.

Indiana University-Purdue University Indianapolis (IUPUI) / Gastric residual volume (GRV) is a clinical assessment to evaluate gastric emptying and enteral feeding tolerance. Factors such as the tube size, tube material, tube port configuration, placement of the tube in the gastric fluid, the amount of fluid and person completing the assessment may influence the accuracy of residual volume assessment. Little attention has been paid to assessing the accuracy of GRV measurement when the actual volume being aspirated is known, and no studies have compared the accuracy in obtaining RV using the three different techniques reported in the literature that are used to obtain aspirate in practice (syringe, suction, and gravity drainage). This in vitro study evaluated three different methods for aspirating feeding formula through two different tube sizes (10 Fr [small] and 18 Fr [large]), tube materials (polyvinyl chloride and polyurethane), using four levels of nursing experience (student, novice, experienced and expert) blinded to the five fixed fluid volumes of feeding formula in a simulated stomach, to determine if the RV can be accurately obtained. The study design consisted of a 3x2x2x4x5 completely randomized factorial ANOVA (with a total of 240 cells) and 479 RV assessments were made by the four nurse participants. All three methods (syringe, suction and gravity) used to aspirate RV did not perform substantially well in aspirating fluid, and on average, the methods were able to aspirate about 50% of the volume available. The syringe and suction techniques were comparable and produced higher proportions of RVs, although the interrater reliability of RV assessment was better with the syringe method. The gravity technique generally performed poorly. Overall, the polyvinyl chloride material and smaller tubes were associated with higher RV assessments. RV assessment is a variable assessment and the three methods did not perform well in this in vitro study. These findings should be further explored and confirmed using larger samples. This knowledge will be important in establishing the best technique for assessing RV to maximize EN delivery in practice and will contribute to future research to test strategies to optimize EN intake in critically ill patients.