Made available in DSpace on 2014-06-11T19:30:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-23Bitstream added on 2014-06-13T19:39:57Z : No. of bitstreams: 1 takegawa_bk_dr_botfm.pdf: 2505732 bytes, checksum: caff44b11cfdc05e43c5608674bbc096 (MD5) / O abaixamento endoanal do cólon (AEC) introduzido em 1998 por De la Torre & Ortega tem tornado obsoleta as cirurgias realizadas em dois ou mais tempos, na correção da moléstia de Hirschsprung (MD). Esta técnica é preconizada principalmente em recém-nascido e lactente. O objetivo deste trabalho é descrever nossa casuística demonstrando os aspectos clínicos, cirúrgicos, complicações, seguimento e medida manométrica do canal anorretal no pré e pósoperatório. Foi um estudo retrospectivo de 6 anos (2001 a 2007) onde foram estudadas 36 crianças com MD operados pela AEC. Os dados clínicos, cirúrgicos e seguimento ambulatorial foram coletados dos prontuários médicos. Foram 36 crianças (26 meninos e 10 meninas). A mediana da idade por ocasião do diagnóstico foi de 36 dias (1 a 2507 dias). Enema opaco revelou zona de transição em 32 pacientes. A manometria demonstrou ausência de reflexo retoesfincteriano em 35 pacientes. A biópsia retal por sucção em 16 pacientes, coradas com acetilcolinesterase confirmou a doença em 12 e em 4 mostrou padrão equívoco. No pré-operatório a média de pressão de repouso foi de 72,8 ± 26,3 mmHg sem diferença estatística com grupo controle (74,5 ± 25,2 mmHg). Na manometria pós-operatória a média foi de 69,7 ± 24,6 mmHg, sem diferença estatística, quando comparada com o pré-operatório. A mediana de idade na cirurgia foi de 154 dias (3 a 2.855 dias). O tempo médio de cirurgia foi de 200,1 minutos (55 a 310 minutos). A média de comprimento ressecado foi de 28,4 cm (11 a 48 cm). Houve 2 pacientes com necessidade de conversão para laparotomia. O tempo médio de internação foi de 6,6 ± 2,1 dias (2 a 48 dias). Evacuação entre as primeiras 48 horas ocorreu em 35 pacientes. Introdução da dieta nas primeiras 48 horas de pós-operatório foi em 35 pacientes. Realizou-se a dilatação anal em 14 pacientes por estenose anal... / The endoanal colon pull-through (ECP) procedure introduced by De la Torre & Ortega in 1998 has caused surgeries performed at two or more times to become obsolete for Hirschsprung’s Disease (HD) correction. This technique is mainly recommended for newborns and infants. The present study aimed at describing our patients, showing clinical and surgical aspects, complications, follow-up and the manometric measurement of the anorectal canal in the pre- and postoperative periods. It was a 6-year retrospective study (2001 a 2007) in which 36 children (26 boys and 10 girls) with HD operated by ECP were evaluated. The clinical, surgical and outpatient follow-up data were collected from the children’s medical charts. Their age median on the occasion of diagnosis was of 36 days (1 to 2,507 days). Opaque enema showed a transition zone in 32 patients, and manometry revealed the absence of rectosphincteric reflex in 35 patients. Suction rectal biopsy in 16 patients, as stained by acethylcolinesterase, confirmed the disease in 12 and showed an equivocal standard in 4 patients. In the preoperative period, the at rest pressure mean was of 72.8 ± 26.3 mmHg without a statistical difference in relation to the control group (74.5 ± 25.2 mmHg). In postoperative manometry, the mean was of 69.7 ± 24.6 mmHg, without statistical difference as compared to that of the preoperative period. The age median at the time of surgery was of 154 days (3 to 2.855 days). The mean surgery duration was of 200.1 minutes (55 to 310 minutes). The mean resected length was of 28.4 cm (11 to 48 cm). Two patients needed to be converted to laparotomy. The mean hospitalization period was of 6.6 ± 2.1 days (2 to 48 days). Bowel voiding in the first 48 hours occurred in 35 patients. Diet introduction in the first postoperative hours occurred in patients. Anal dilation was performed by anal stenosis in 14 patients... (Complete abstract click electronic access below)

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A incidÃncia e mortalidade por cÃncer colorretal apresentam tendÃncia ao crescimento. O cÃncer colorretal à a quinta neoplasia mais incidente no Brasil. A etiologia està relacionada com hereditariedade e modificaÃÃes no estilo de vida. A lesÃo prÃ-neoplÃsica mais precoce com presenÃa de displasia à o foco de cripta aberrante, estando relacionada como lesÃo precursora de adenomas colorretais e cÃncer em humanos. Entender a natureza destas lesÃes contribui na pesquisa de agentes preventivos eficazes no cÃncer colorretal. O objetivo foi verificar o potencial quimiopreventivo da soluÃÃo aquosa do lÃtex de Euphorbia tirucalli L. quanto a formaÃÃo de focos de cripta aberrante (FCA) em ratos induzidos com azoximetano (AOM). Foram usados 32 ratos da linhagem Wistar, machos, com peso mÃdio estimado de 100g -200g (4 â 6 semanas). Foram distribuÃdos aleatoriamente em 04 grupos contendo 08 animais, denominados: GRUPO 01- grupo estudo com ratos induzidos com AOM e tratados com extrato aquoso do lÃtex da E. tirucalli L..GRUPO 02 - grupo estudo controle com ratos induzidos com AOM sem tratamento com extrato aquoso do lÃtex da E tirucalli L..GRUPO 03 - grupo estudo controle sem induÃÃo com AOM e tratados com extrato aquoso do lÃtex da E. tirucalli L.. GRUPO 04 - grupo estudo controle sem induÃÃo com AOM e sem tratamento com extrato aquoso do lÃtex da E. tirucalli L..Os animais dos Grupos 01 e 02 receberam injeÃÃo de AOM 12 mg/kg, intraperitoneal (IP), uma vez por semana, por 02 semanas. Uma semana antes do inÃcio da administraÃÃo do carcinÃgeno, foi administrada diariamente soluÃÃo por gavagem, respectivamente, de extrato aquoso do lÃtex da E. tirucalli L. 400mg/Kg e soluÃÃo fisiolÃgica a 0,9% em uma administraÃÃo diÃria. Os Grupos 03 e 04 nÃo foram induzidos com AOM e receberam soluÃÃo por gavagem, respectivamente, de extrato aquoso do lÃtex da E. tirucalli L. 400mg/Kg e soluÃÃo fisiolÃgica a 0,9%. Todos os grupos continuaram recebendo a soluÃÃo por gavagem diÃria atà o dia estabelecido para eutanÃsia. Foram mortos na 15 semana, apÃs a induÃÃo com carcinÃgeno ou administraÃÃo IP de soluÃÃo estÃril para injeÃÃo. Os animais foram avaliados quanto ao peso, alteraÃÃo clÃnica, presenÃa de adenomas ou tumores cÃlicos, e quanto à presenÃa de FCA e o nÃmero de criptas por cada foco (multiplicidade) de acordo com a localizaÃÃo cÃlica, definidas regiÃo distal, medial e proximal. Verificamos no presente estudo que o extrato aquoso da E tirucalli L. (400mg/kg) apresentou uma diminuiÃÃo significante do nÃmero total de FCA do grupo 01 em relaÃÃo ao grupo 02 (p<0,001), adicionalmente a multiplicidade nestes grupos apresentou diferenÃa significante (p<0,0001) quanto a presenÃa de &#8804; 5 criptas por foco em todo cÃlon examinado. Este estudo sugere que extrato aquoso de E. tirucalli L tem potencial quimiopreventivo em relaÃÃo a carcinogÃnese cÃlica, inibindo a formaÃÃo de FCA em ratos induzidos com AOM. / Colorectal cancer is the fifth most frequently diagnosed malignancy in Brazil. The etiology may be related with inherited and life-style that can be modified. Aberrant crypt foci have been recognized as early preneoplastic lesions and being related with colorectal adenoma and precursors of cancer in humans. Undertanding the nature of early appearing lesions efforts to find effective agents in colorrectal cancer. The aim of this study was verify the potential chemopreventive of aqueous solution of the latex of Euphorbia tirucalli L. in aberrant crypt foci (ACF) in rats induced with azoxymethane (AOM). Thirty-two Wistar male rats were used, average weight 100g -200g (4 - 6 weeks). They were randomly divided into 04 groups of 08 animals each. Group 01 with rats induced with AOM and treated with aqueous extract of the latex of E. tirucalli L., group 02 with rats induced with AOM without treatment with aqueous extract of the latex of E. tirucalli L., group 03 with rats without AOM induction and treated with aqueous extract of the latex of E. tirucalli L. and group 04 with rats without induction with AOM and without treatment with aqueous extract of the latex of E. tirucalli L.. The animals of the groups 01 and 02 were injected intraperitoneallly (IP), with AOM once a weekly for 02 weeks at a dose level of 12 mg/kg body weight. One week before the beginning of the administration of the carcinogen, it was administered solution daily by intragastric gavage, respectively, aqueous extract of latex of E. tirucalli L. 400mg/Kg and physiologic solution to 0,9%. The groups 03 and 04 were not induced with AOM and they received daily solution by gavage, respectively, aqueous extract of the latex of E. tirucalli L. 400mg/Kg and physiologic solution to 0,9%. All groups continued receiving daily solutions by intragastric gavage until the day established for euthanasia. All animals were sacrificed by diethyl ether inhalation 15th week, after AOM initiation or sterile solution injected IP. The animals were evaluated concerning to the weight, clinical alteration, presence of adenomas or colic tumors, and the presence of ACF and the number of crypts for each focus (multiplicity) in agreement with colic location, defined area distal, medial and proximal. We verified in the present study that the aqueous extract of E. tirucalli L. (400mg/kg) presented a significant decrease of the global number of ACF group 01 compared to the group 02 (p<0,001). Additionally, the multiplicity in these groups showed significant decrease (p<0,0001) in the number of ACF with 5 crypts/focus in the whole large intestine. This study suggests the aqueous extract of E. tirucalli L. has potential chemopreventive against colon carcinogenesis with inhibition of the formation of ACF in rats induced with AOM .

Orientadores: Claudio Saddy Rodrigues Coy, João Jose Fagundes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T01:10:44Z (GMT). No. of bitstreams: 1 Pereira_YaraEmantneAmaral_M.pdf: 1682869 bytes, checksum: 9d5801f67ab43156ce97cd3a10778b4d (MD5) Previous issue date: 2007 / Resumo: Introdução: As complicações das anastomoses intestinais podem ser graves com altos índices de morbi/mortalidade. Vários fatores relacionados à qualidade das mesmas têm sido objetos de estudos, como técnica operatória, fios de sutura ou variáveis bioquímicas, enquanto que outros, não associados diretamente à técnica cirúrgica, são menos avaliados, como por exemplo, a influência de choque hemorrágico. Objetivo: Avaliar o efeito do choque hemorrágico em anastomoses de cólon em ratos, com teste de ruptura à distensão por líquido. Material e Método: Foram utilizados ratos da linhagem Wistar, com idade aproximada de 90 dias e peso variando de 310 gramas a 380 gramas. Os animais foram divididos em dois grupos, sendo o grupo G1, composto por 10 animais submetidos à anastomose de cólon em condições de normovolemia e o grupo G2, composto por 10 animais submetidos à anastomose de cólon em condições de hipovolemia. O choque foi instalado através da retirada de meio mililitro de sangue a cada dois minutos, até que se atingissem valores de pressão arterial média (PAM) de 50mmHg ou volume total de retirada correspondente a 30% da volemia. Foram realizadas dosagens séricas de lactato (mmol/l) no início do procedimento e ao término do mesmo. Os valores séricos médios de lactato ao término da cirurgia foram de 1,91 mMol/l no grupo G1 e de 3,69 mMol/l no grupo G2 (p<0,05) No quinto dia de pós-operatório, os animais foram submetidos à eutanásia e tiveram suas anastomoses testadas por teste de resistência à pressão de ruptura à distensão por líquido. Resultados: No grupo G1, o valor médio da pressão de ruptura do cólon à distensão por líquido foi de 160,7 mmHg enquanto que no grupo G2 foi de 152,1mmHg (p>0,05). Conclusão: A presença de choque hemorrágico, nas condições estabelecidas neste estudo, não exerceu influência em anastomoses de cólon em ratos, avaliadas com teste de ruptura à distensão por líquido / Abstract: Introduction: Intestinal anastomoses complications can be very serious, with high morbidity and mortality rates. Several factors related to their quality have been object of studies, such as technical aspects, suture threads or biochemical variables. Others, not directly associated with the surgery technique, are less evaluated, such as the influence of hemorrhagic shock. Objective: Evaluate the effect of hemorrhagic shock in colonic anastomoses in rats, with resistance test to rupture by liquid distension. Methods and Material: Wistar lineage rats, averaging 90 days old and weight varying from 310 to 380 grams were divided into two groups. In the G1 group, 10 animals were submitted to colonic anastomoses in normovolemic terms and the G2 group 10 animals were submitted to colonic anastomoses in hipovolemic conditions. The shock was caused by half milliliter blood withdrawal, done every two minutes, until reached the value of average arterial pressure of 50mmHg or total volume of corresponding withdrawal to 30% of volemia. Serum lactate dosages were carried out at the beginning and at the end of the procedure. The average serum values lactate at the end of the surgery were 1,91 mMol/l in the G1 group and 3,69 mMol/l in the G2 group (p<0,05). On the fifth postoperative day, the animals were submitted to euthanasia. The anastomoses were evaluated with resistance test to rupture by liquid distension. Results: In the G1 group, the average value of colonic rupture was 160,7mmHg whereas in the G2 group was 152,1mmHg (p>0,05). Conclusion: Hemorrhagic shock, in the established conditions of this study, had no influence in colonic anastomosis in rats evaluated with resistance test to rupture by liquid distention / Mestrado / Cirurgia / Mestre em Cirurgia

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este estudo experimental verificou a eficÃcia do uso de um lacre plÃstico no fechamento do coto distal do cÃlon sigmÃide comparando com sutura manual em plano Ãnico, contÃnuo e extramucoso utilizando fio de polipropileno. Foram utilizados 30 animais (Canis familiaris) fÃmeas, pesando entre 8,0 e 18,0 kg, clinicamente sadios, oriundos do canil da Prefeitura Municipal de Teresina, PiauÃ. Foram distribuÃdos em dois grupos de 15 animais; submetidos a laparotomia com secÃÃo do cÃlon sigmÃide, com fechamento do coto distal com sutura cotÃnua e extramucosa com fio de polipropileno ( Grupo I â Controle) e fechamento do coto distal com lacre plÃstico ( Grupo II- Estudo ). Todos os animais de ambos os grupos foram submetidos à anastomose colo-retal, tÃrmino lateral e avaliados no trans e pÃs-operatÃrio imediato por mÃdico veterinÃrio, sendo a alimentaÃÃo à base de raÃÃo padrÃo e Ãgua, ad libitum, instituÃda quando se observou evacuaÃÃo. Todos os animais foram submetidos à eutanÃsia no 21 DPO apÃs anestesia venosa com Cloridrato de Cetamina e aplicaÃÃo de cloreto de potÃssio 20% via endovenosa ; realizou-se nova laparotomia e avaliaÃÃo da anastomose colo-retal, correspondendo o cÃto distal do sigmÃide ,este segmento foi submetido a teste de rompimento de sutura. Estatisticamente foi realizado teste estatÃstico de VariÃncia aplicando-se o Teste SNK e confirmado com teste Qui-quadrado. Durante realizaÃÃo do teste de tensÃo, ocorreu rompimento do fechamento do coto cÃlico distal em quatro animais de cada grupo, nÃo havendo diferenÃa significativa entre os grupos (p>0.05). O tempo operatÃrio mÃdio foi 27,7 min. E 24,7 min., nos Grupos I e II respectivamente, nÃo havendo diferenÃa estatisticamente significante entre os dois grupos (p=0,09). A pressÃo mÃdia de ruptura foi 145,0mmHg e 195,0mmHg nos Grupos I e II respectivamente, nÃo havendo diferenÃa estatisticamente significante entre eles (p=0,057). O fechamento do cÃlon distal com lacre apresentou a mesma seguranÃa e eficÃcia do fechamento com fio polipropileno 3-0. / The objective of this experimental study was to compare the efficacy of two techniques of distal sigmoid stump closure: plastic zip-tie versus manual, running extramucosal single-layer suture with polypropylene thread. The study included 30 clinically healthy female dogs (Canis familiaris) weighing 8&#8722;18 kg supplied by the local municipal dog pound (Teresina, PiauÃ). The animals were distributed in two groups of 15 animals each and submitted to laparotomy, colon resection and closure of the distal sigmoid stump with either running extramucosal suture using 3-0 propylene thread (Group I) or a plastic zip-tie (Group II). All animals were submitted to latero-terminal colorectal anastomosis and were evaluated transoperatively and immediately after surgery by a veterinarian. Standard chow and water was provided ad libitum once evacuation had been observed. On the 21st postoperative day the animals were anesthetized with Cloridrate Cetamina i.v. and euthanized with 20% potassium chloride i.v. A second laparotomy was performed to evaluate the colorectal anastomosis and submit the sigmoid stump to a wound disruption test. Findings were submitted to variance analysis, followed by the Student-Newman-Keuls test and the Chi-square test for confirmation. Wound disruption occurred in four animals from each group, with no statistically significant difference between the groups (p>0.05). The average time of surgery was 27.7 min (Group I) and 24.7 min (Group II), with no statistically significant difference between the groups (p=0.09). The average disruption pressure was 145.0 mmHg (Group I) and 195.0 mmHg (Group II), with no statistically significant difference between the groups (p=0.057). Closure of the sigmoid stump may be as safely performed with plastic zip-tie as with conventional continuous suture using 3-0 polypropylene thread.

M.A. / Irritable Bowel Syndrome is defined as a chronic relapsing functional bowel disorder of unknown causes (Weber & McCallum, 1992). IBS is characterized by attacks of abdominal pain and change of bowel habit resulting in diarrhoea, constipation or both, where no structural alteration of the colon is found (Varis, 1987). The symptoms appear to result from a dysfunction of the intestine and are therefore said to be “functional” (Heaton & Thompson, 1999). The prevalence of IBS in the general population of Western countries is 14-24% of women. It is the most common cause of gut symptoms, and the most common reason that people go to their family doctor with a gut complaint. Despite all of this, physicians are still groping to understand the pathogenesis of IBS. The secret of success with IBS is to recognize it quickly and confidently. This is done primarily from the history, as there are no clinical tests that may be done to diagnose IBS. Once the diagnosis has been made it is of utmost importance that the sufferer is told, the syndrome is explained, and a good relationship is established with the health-care giver. Thereafter it becomes important to search for unspoken agendas in the life of the sufferer. According to the literature, stress can exacerbate IBS, and sexual, physical and emotional abuse can pose complex problems that require the assistance of a skilled counsellor. These problems, if left, may lead to the intensified symptoms of IBS. Society is becoming increasingly abusive and women and children often bear the brunt of physical, emotional and sexual abuse. Studies in America of women who present at medical facilities as well as those sampled from the community have found abuse rates that range from 20-76%. There is no reason to believe that these figures would be that different for South Africa. These studies have also found that abused women report a significantly higher number of medical problems and health-care system usage. A number of researchers have also found that there was a significant association between IBS and sexual abuse and physical abuse in childhood and adulthood. For the counselling psychologist the challenge is to unravel the mechanisms behind the symptoms, and to provide a rationale for therapy. The role that abuse may play in the development of IBS forms the cornerstone of the present study.

In summary, this thesis has explored the anti-cancer mechanisms of novel medicinal compounds via targeting calpains or S100A4 in the treatment of colon cancer, which could facilitate future establishment of effective medicinal compounds in the treatment of metastatic colon cancers with known molecular targets.;The incidence of colon cancer in Hong Kong and worldwide is on a rising trend, while its metastatic development is the leading cause of cancer-related deaths. Understanding the molecular mechanisms of how tumors progress and metastasize to secondary sites, at both biological and genetic levels, could enable us to identify potential molecular targets in drug development. In the present study, we explored how manipulation of signaling pathways by targeting calpains and S100A4 could facilitate the development of anti-tumor and anti-metastatic drugs.;The study investigating drug targeting on S100A4 in both in vitro and in vivo models had shown that the pharmacological store-operated calcium channel blocker would suppress S100A4-mediated migration by weakening extracellular S100A4-mediated calcium responses. The effects on S100A4-induced metastasis formation were confirmed in vivo with reduced splenic tumor volume and decreased number of liver metastases. These results have provided new insights to correlate between S100A4 and calcium signaling, making an important step forward in characterizing the dependence of calcium homeostasis in the process of metastasis, providing a novel strategy for S100A4-mediated metastasis.;With respect to the targeting on calpains, it was discovered that total Astragalus saponins (AST) and cryptotanshinone (CPT) are effective anti-cancer agents that elicit the endoplasmic reticulum (ER) stress response. They act by upregulating the expression of glucose-regulated protein (GRP) 78, leading to the initiation of apoptosis when the ER recovery process begins to fail. In particular, CPT caused rapid and sustained increase in cytosolic calcium in colon cancer cells that was accompanied by early GRP78 overexpression. The increase in cytosolic calcium was blocked by pre-treatment of BAPTA-AM through depletion of the ER calcium store. In consistent with these, we also confirmed that CPT significantly increased calpain activity, which could be blocked by calcium chelator or calpain inhibitors. Furthermore, a dynamic interaction between GRP78 and calpain under ER stress was unveiled during AST or CPT exposure. The degree of association was increased following prolonged ER stress, and suppressed either as the ER recovery process failed or with the presence of calpain inhibitors. Besides, inhibition of calpain activity suppressed NF-κB activation (a consequence of ER stress) and substantially enhanced the effects of CPT to promote apoptosis. More importantly, it was confirmed that the effects of calpain inhibitors to sensitize colon cancer cells to ER stress-associated apoptosis are p53-dependent. The anti-tumorigenetic effects of CPT were further demonstrated in vivo in xenografted nude mice by trageting calpains and in combination with calpain inhibitors.

No description available.

Background: Colorectal cancer is the third most common cancer and cause of related deaths worldwide. Early colorectal cancer diagnosis is vital in reducing incidence and mortality. There is a need for the development of non-invasive screening tools for enhancing the detection of the disease. Cancer specific peptides are useful cancer targeting agents that can be used to specifically improve early detection strategies. Several cancer targeting peptides have been identified. Previous work investigated the specific binding of three of these peptides (p.C, p.L and p.14) conjugated to quantum dots and were found to bind to colorectal cancer cell lines (HT-29 and Caco-2). However, their uptake, localization and biodistribution in an in vitro and in vivo colorectal cancer model have not been determined. This is essential in gaining an understanding for future diagnostic or therapeutic based applications. Primary Aim: The aim of this study was investigate the localization of three selected peptides p.C, p.L and p.14 conjugated to gold nanoparticles in an in vitro and in vivo colorectal cancer model using HRTEM. Methodology: The AuNP/peptide conjugates were characterized by HRTEM and DLS. For in vitro studies; HT-29, Caco-2 and C3A cells were exposed to the AuNP-p.C, AuNP-p.L and AuNP-p.14, collected and processed for HRTEM to assess targeting and localization. For in vivo studies; the establishment of a colorectal cancer model using the AOM/DSS model 1 and 2 was conducted. Wistar rats were assigned to 6 groups, five experimental and 1 control group. Group 1 received AOM/DSS method 1 and was treated with AuNP-p.L. Group 2 and 3 received AOM/DSS method 2 and were treated with AuNP-p.C and AuNP-p.14. Group 4 and 5 remained healthy and treated with AuNP-p.C and AuNP-p.14. Group 6 remained healthy receiving no nanoparticle treatment. After treatment, rats were sacrificed and tissue was processed for HRTEM. Tissue chosen for HRTEM analysis included: Group 1 (inflamed colon, rectum, pancreatic and kidney), Group 4 (kidney) and Group 5 (liver). Results: results obtained from nanoparticle characterization suggested that nanoparticles were conjugated to their respective peptides and were stable in dispersion. For in vitro studies, results suggested no AuNP targeting and localization in HT-29 cell lines. For in vivo studies, no colorectal cancer tumours were induced. TEM micrographs did not indicate the presence of nanoparticles in colon, rectum, pancreatic, kidney and liver tissue. However, AuNPs were found in the kidney tissue (group 4). Conclusion: Although the overall objectives were not met, this study provided insight into TEM cell preparation and optimization for future nanoparticle cell interaction research. This study also demonstrated the absence of AuNPs in healthy tissue and the presence of AuNPs in healthy kidney tissue through renal clearance, a favourable quality for diagnostic or therapeutic applications.

Colorectal cancer (CRC) is a common disease with significant morbidity and mortality. In spite of significant advances in understanding the molecular signaling in this disorder, unanswered questions remain. Cyclooxygenase-2 (COX-2) and β-catenin have established roles in colorectal carcinogenesis, with both being upregulated early in the disease course. The role of peroxisome proliferator-activated receptor γ (PPARγ) is less clear, but has been shown to be downregulated in colon cancer models. Butyrate, a short chain fatty acid, produced by colon microbiota and transported into the colonocyte by transporter proteins, appears to be important in early carcinogenesis. The butyrate concentration is reduced in CRC and so are its transporters. Interleukin-17 (IL-17) plays a role in colitis-associated colorectal cancer (CAC), but its function in sporadic CRC is less clear. Similarly, Protein kinase C (PKC) has proven involvement in many solid tumours, including CRC, but its exact mechanistic role is still speculative. AIM: To investigate the role and possible signaling pathways of the major role players, β-catenin, COX-2 and PPARγ in early CRC. Further, to elucidate the mechanistic pathways of butyrate and its transporters, IL-17 and PKC in CRC. METHOD: Informed consent was obtained for all patients. Patients were recruited in various disease categories, including normal, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and CRC. Colon biopsy specimens were obtained during colonoscopy and used for immunohistochemistry (IHC) and gene expression analysis of the above genes by quantitative polymerase chain reaction (qPCR). RESULTS: β-catenin mRNA and protein expression was increased in CRC and the IBD groups compared to the normal group, while it was reduced in the IBS groups. COX-2 mRNA expression showed a steady increase from normal, through IBS, IBD and CRC groups to a statistically significant degree. The COX-2 protein expression, however, did not match the mRNA expression with increased COX-2 protein expression in normal and IBS groups and reduced expression in IBD and CRC groups. PPARγ mRNA expression was unchanged in IBD and CRC groups, but significantly increased in the IBS group compared to normal. Butyrate transporter, SLC16A1 mRNA was significantly reduced in CRC, but also in the IBS groups, which was unexpected. In the IBD group, SLC16A1 mRNA was unchanged in Crohn’s disease (CD) but significantly reduced in ulcerative colitis (UC). Similarly, SLC5A8 mRNA expression was significantly reduced in the CRC as well as the IBS groups. In the IBD groups, SLC5A8 was unchanged in UC but significantly increased in CD. IL-17 mRNA expression was significantly reduced in CRC and IBS groups, but unchanged in the IBD groups. PKCε mRNA was significantly increased in CRC as expected. In the IBD groups, PKCε mRNA was unchanged in CD but significantly increased in UC. In the IBS groups, PKCε mRNA in constipation –IBS (C-IBS) was significantly reduced, but unchanged in diarrhoea – IBS (D-IBS). CONCLUSIONS: β-catenin mRNA and protein expression was increased in CRC and the CRC promoting IBD groups. COX-2 protein expression was incongruent with the COX-2 mRNA expression and this may reflect homeostatic control mechanisms. High COX-2 mRNA expression in CRC and CRC promoting IBD groups may be a secondary phenomenon reflecting the inflammatory milieu, rather than a true carcinogenesis-related event. PPARγ does not appear to play a central role in early colon carcinogenesis, in spite of available literature suggesting otherwise. Butyrate transporters showed inconsistent results and for now no firm conclusions can be drawn from this. IL-17 may play a role in CAC as confirmed in this and other studies, but its role in sporadic CRC is tenuous and requires further investigation. Likewise for PKCε, upregulation is associated with increased tumourigenecity as shown in this study, however, the mechanistic pathway(s) involved is still speculative and requires further study.

Irritable bowel syndrome (IBS) is characterized by chronic abdominal pain/discomfort along with altered bowel habits, which accounts for a large proportion of gastrointestinal (GI) disorders worldwide. While psychiatric distress like depression is one of the most frequent comorbidities in IBS patients, which not only influences the quality of life, it also leads to a substantial economic burden and inefficient treatment in IBS patients. Inflammation, altered activities of the HPA axis, aberrant central neuroplasticity and neurotransmission have been highly regarded as pathogenic factors of the depression. Whereas, in recent years, dysfunctions in the gut microbial community has been increasingly discovered to provoke depression disorder. Considering that gut dysbiosis plays causal role in IBS progression, dysfunction of the gut microbiota has been speculated for contributing to the depressive symptoms in IBS (IBS-DP) patients. However, whether and how gut dysbiosis affecting IBS-DP patients remain unclear. We hypothesized that gut microbiota changes contribute to the development of IBS-DP and the change of gut microbiota-driven metabolites induces the structural and/or functional changes of the central nervous system (CNS), thus resulting in the development of IBS-DP. In this thesis, IBS patients with and without depression and animal models of IBS have been systematically studied, to investigate whether gut dysbiosis mediates depressive disorder in IBS. Firstly, we conducted a cross-sectional study involving the distribution of depressive disorder in the IBS population of Hong Kong. According to this survey, we found that there is 36.6% (135/369) of IBS patients showed symptoms of depression. The severity of depressive symptoms was positively associated with the harshness of visceral pain and bloating signatures in IBS patients. Secondly, in comparison to the non-depression of IBS (IBS-ND) group, faecal metagenomic results unveiled the disrupted gut microbiota in IBS-DP patients, mainly with the deficiency of several beneficial bacterial groups, including Akkermansia, Bifidobacterium and Eubacterium, whereas the gut microbiota profile between IBS-ND patients and healthy controls (HCs) showed no significant changes. Compared with HCs, enzyme-linked immunosorbent Assay (ELISA) results showed higher levels of serum IL-1β, IL-6, and TNF-a in IBS-DP patients, indicating a low-grade peripheral inflammation in IBS-DP patients. Moreover, the abundance of Akkermansia muciniphila (A. muciniphila), was negatively correlated with Hamilton Rating Scale for Depression (HAMD) score and Zung Self-Rating Depression Scale (SDS) score, IL-1β, TGF-β, and TNF-a in IBS-DP patients. These findings indicate that gut dysbiosis, especially deficiency in A. muciniphila, is related to the depressive symptoms and inflammation in IBS-DP patients. Thirdly, in a neonatal maternal separation (NMS) rat model, behavioural tests such as colorectal distention (CRD) test, open field test (OFT), forced swimming test (FST), and sucrose preference test (SPT) results showed visceral hypersensitivity and depression symptoms in rats. These results indicate that the model can successfully mimic the visceral hyperalgeisa and the depression-like behaviour of IBS-DP. Immunohistochemical analysis showed an altered morphology and decreased the quantity of astrocytes in the hippocampus of NMS rats when compared with that of controls. More importantly, the mRNA expressions of genes related to Astroglial glutamate transmission including glutamate transporters (GLTs), glutamate receptors, and also glutamate-related exchangers, as well as astrocyte biomarker glial fibrillary acidic protein (GFAP), which are mediated with chronic inflammation and/or stress, were decreased in NMS rats when compared with the control group. These results indicate that impaired astroglial glutamate neurotransmission in NMS rats. Furthermore, pseudo-GF rats with faecal microbiota transplantation (FMT) of NMS microbiota were also conducted, and results showed that the association of A. muciniphila deficiency, depressive-like behaviours and impaired astroglial glutamate neurotransmission were repeated in the rat recipients. These results indicate a causal relationship between NMS microbiota and depressive phenotype, involving dysfunction of the astrocyte- glutamate pathway. Fourthly, to further verify the role of A. muciniphila in NMS microbiota-induced depressive phenotype and impaired astrocytic glutamate pathway, we orally administered live and heat-killed A. muciniphila bacteria in NMS adult rats. A. muciniphila (108 CFU in 1mL PBS) was administered once-daily for four consecutive weeks. Besides, rifaximin and fluoxetine were also separately treated in NMS rats as control groups. Rifaximin is a broad-spectrum GI-specific antibiotic that is commonly used for IBS treatment, and fluoxetine, a selective serotonin re-uptake inhibitor, is one of the most frequently prescribed anti-depressants. The results showed that A. muciniphila efficiently improved depressive-like behaviours, attenuated the impaired astrocytic glutamate neurotransmission, as well as restored the normal morphology and number of astrocytes in the hippocampus of NMS rats. While rifaximin-treated rats only exhibited amelioration of visceral pain, and fluoxetine group mainly performed antidepressant effect, without any significant change in astrocytic glutamate neurotransmission impairment. These results demonstrate that A. muciniphila improves depressive symptoms in IBS phenotype and ameliorate astroglial-glutamatergic pathway dysfunction. Whether and how A. muciniphila modulates astroglial glutamate transmission, therefore leading to the improvement of depressive symptom in IBS, remains to be further investigated. Taken together, the works of this thesis, combining both clinical and animal studies reveal that gut dysbiosis, particularly deficiency of A. muciniphila, contributes to the development of IBS-DP via regulating the astroglial glutamatergic pathway. This study gives a different direction to microbial-guided therapy for the IBS-DP patients in the future