The objective of this study is to address some important questions associated with stomach cancer patients using the data from the Surveillance Epidemiology and End Results (SEER) program of the United States. To better understand the behavior of stomach cancer, we first perform parametric analysis for each patient group (white male, white female, African American male, African American female, other male and female) to identify the probability distribution function which can best characterize the behavior of the malignant stomach tumor sizes. We evaluate the effects of patients’ age, gender and race on the malignant stomach tumor sizes by developing quantile regression models, which gives us a better understanding of the behavior of the malignant stomach tumors. We also proposed statistical models with respect to patients’ malignant stomach tumor size as a function of age for different races and gender group, respectively. The proposed models were evaluated to attest their prediction quality. Furthermore, we have identified the rate of change of the malignant tumor size as a function of age, for gender and race. We evaluated the routine treatment of stomach cancer using parametric and nonparametric survival analysis. We have found that stomach cancer patients who receive surgery with radiation together have a better survival probability than the patients who receive only radiation. We performed decision tree analysis to assist the physician in recommending to his patients the most effective treatment that is a function of their characteristics.

published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Gastric cancer is one of the main health issues in Lithuania. The risk factors of the disease are related to nutrition and environment. There were no epidemiological studies on that subject in the country. The aim of the study was to assess a relationship between gastric cancer risk and lifestyle (diet, alcohol use, smoking, physical activity), work environment and some social factors. A hospital based case-control study included 379 cases with newly histologically confirmed diagnose of gastric cancer and 1137 controls that were cancer and gastric diseases free. Cases and controls matched by gender and age (+5yr.). Ratio of case and controls was 1:3. A questionnaire was used to collect information on possible risk factors of gastric cancer. The odds ratios (OR) and 95% confidence intervals (CI) for gastric cancer were calculated by a conditional logistic regression. Our data showed that salt and salt processed food items increased risk of gastric cancer. After adjustment for a certain confounders (alcohol use, smoking, family history on cancer, Body Mass Index at 20 yr of age, education level, residence, other dietary habits that were related to the outcome, and physical activity) subjects that like salty food or put salt additionally to prepared meal had three times higher risk of gastric than those who do not do that. The risk of the disease increased two times eating salted meat 1-3 times a month and more, having smoked meat 3-4 times a week and more, and using smoked... [to full text]

Skrandžio vėžys yra ketvirta pagal dažnį ir antra pagal mirtingumą onkologinė liga pasaulyje. Sergančių šia liga 5 metų išgyvenamumas siekia tik 25 proc. Esant didelei ligos atkryčio rizikai dažniausiai skiriama adjuvantinė chemoterapija, nors daugumoje atsitiktinių imčių studijų statistiškai reikšmingo išgyvenamumo pagerėjimo nenustatyta. Dažniausia skrandžio vėžio gydymo nesėkmės priežastis yra lokoregioninis recidyvas (40-65 proc. ligonių, kuriems atliktos radikalios operacijos) ir pilvaplėvės metastazės. Siekiant sumažinti lokoregioninių recidyvų dažnį, pradėtas taikyti suderintas chemospindulinis gydymas. Šio tyrimo tikslas- nustatyti adjuvantinio gydymo efektyvumą po radikalių skrandžio vėžio operacijų su D2 limfadenektomija ir pagrįsti šio gydymo metodo tikslingumą. Darbo tikslui įgyvendinti buvo suformuluoti šie uždaviniai. 1. Įvertinti radikaliai dėl skrandžio vėžio operuotų su D2 limfadenektomija pacientų išgyvenamumą taikant adjuvantinį chemospindulinį gydymą arba adjuvantinę chemoterapiją. 2. Įvertinti adjuvantinio chemospindulinio gydymo toksiškumą po radikalių operacijų su D2 limfadenektomija, palyginti jį adjuvantinės chemoterapijos 5-fluoruracilu ir leukovorinu sukeliamu toksiškumu. 3. Įvertinti ankstyvos pooperacinės intraperitoninės chemoterapijos toksiškumą ir palyginti jos efektyvumą taikant su adjuvantiniu chemospinduliniu gydymu. 4. Palyginti gyvenimo kokybę po radikalių operacijų dėl skrandžio vėžio atliekant gastrektomiją ir subtotalinę skrandžio... [toliau žr. visą tekstą] / Gastric cancer is the fifth most common cancer and the second leading cause of cancer-related death worldwide. The 5-year survival rate of these patients is approx. 25. Adjuvant chemotherapy is frequently used for treatment, despite the fact that many randomized studies failed to demonstrate a better patient survival. The high rate of recurrence, even in patients undergoing state-of-the art curative resection, suggests that effective adjuvant chemoradiation and chemotherapy might indeed be an attractive concept to improve the overall outcomes of patients with gastric cancer. The aim of this study was to evaluate the effectiveness of the adjuvant therapy after curative resection with D2 lymphadenectomy for gastric cancer and determine its role in the treatment of cancer patients. The goals of this study were: 1. To compare the survival of patients receiving adjuvant chemoradiation or adjuvant chemotherapy after the curative resection with D2 lymphadenectomy for gastric cancer. 2. To evaluate the toxicity of the adjuvant chemoradiation after the curative resection with D2 lymphadenectomy for gastric cancer and to compare it with the toxicity caused by adjuvant chemotherapy with 5- Fluorouracil and Leucovorin. 3. To assess the toxicity of the early postoperative intraperitoneal chemotherapy and compare its effectiveness with the combined intraperitoneal chemotherapy and adjuvant chemoradiation therapy. 4. To compare the quality of life after the total and subtotal... [to full text]

This study investigated the antiviral, chemoprotective and proliferative effects of strawberry anthocyanins on herpes simplex virus type-1, cancerous cell lines HT-29 and AGS, and normal cell lines Hs 738.St/Int and CCD-18Co. Antiviral properties were measured by infecting vero cells from adult grivet (Cercopithecus aethiops) with herpes simplex virus type-1 (HSV-1) and treating with a concentration of 1.25-20 µg/mL of strawberry anthocyanins. Infectivity and replication were quantified for herpes simplex virus type-1 using the direct plaque assay and reporting PFU/mL. Strawberry anthocyanins (>20 µg/mL) inhibited the herpes simplex virus infectivity in vero cells by 100% (p<0.05). Strawberry anthocyanins at concentrations of 5, 10 and 20 μg/mL were reduced to 75.36, 57.98, and 31.46 percent of the control (100%) (p<0.05). Chemoprotective and proliferative effects of strawberry anthocyanins were analyzed for the human cell lines AGS, Hs 738.St/Int, HT-29, and CCD-18Co at a concentration of 25-200 µg/mL and quantified using the sulforhodamine-B assay. Growth inhibition occurred at a level of ≥87% for treatment concentrations 100 and 200 µg/mL for the cancerous AGS and HT-29 cell lines (p<0.0001). Proliferation rates for the normal Hs 738.St/Int and CCD-18Co cell lines increased at all treatment concentrations of 25-200 μg/mL (p<0.0001); suggestingthat the observed proliferative activity may be associated with anthocyanin treatment.Strawberry anthocyanin treatment concentration worked in a dose dependent manner for the HSV-1 and the cancerous AGS and HT-29 cells. The caspase-3 assay was performed to demonstrate potential mechanism of action and confirmed thatanthocyanin treatments play a role in apoptosisby the up regulation of caspase-3.Significantdifferences were seen between the growth characteristics of cancerous cell linescompared to their equivalent normal cell lines (p<0.0001). In summary, the antiviral findings suggest that strawberry anthocyanin extracts could be an effective topical treatment and/or prophylactic agent for oral herpetic infections (HSV-1). Also, the in vitro chemoprotective effect of strawberry anthocyanins found may be relevant to in vivo work in the future because when anthocyanins are consumed in the diet they come in direct contact with the gastrointestinal tract and may provide chemoprotection upon contact with the stomach and gastrointestinal tract’s epithelial cell layer.

As atividades enzimáticas e isoenzimáticas da CK e da LD foram determinadas nos tecidos gástricos neoplásico e da margem de ressecção e no soro de indivíduos com adenocarcinoma de estômago, submetidos à gastrectomia. O tecido gástrico neoplásico aapresentou índices CKBB/Cktotal e LD5/LD1, bem como atividade da LD5, superiores aos da margem de ressecção correspondente. No pré-operatório, os indivíduos estudados apresentaram elevação da atividade sérica da CK BB (100%) e da CK MB (69%). Este fato, possivelmente, resultou da liberação dessas isoenzimas pelo próprio neoplasma ou, também pelo tecido normal adjacente. As atividades séricas das isoenzimas da LD apresentaram-se dentro dos valores de referência, nesse período. Após a gastrectomia, houve aumento significativo das atividades isoenzimáticas séricas da CK e da LD relação àquelas do pré-operatório, notadamente, no 1º período pós-operatório. Tais alterações foram atribuídas à liberação dessas isoenzimas pelos tecidos lesados durante o ato cirúrgico. / Abstract not available

Gastric aspirate specimens were collected from patients w~th clinically diagnosed gastric carcinoma and from non-carcinoma patients. The nitrite concentration and pH values of the aspirates were measured, the microorganisms present in selected specimens were isolated and identified, and the mutagenicity ratios of the aspirates were determined. The median nitrite concentration of the gastric aspirates from the carcinoma patients was significantly higher than that obtained for the non-carcinoma patients. A positive correlation was found between the nitrite concentration and the pH values of all the specimens tested, and a marked increase in nitrite levels at pH values above 6,0 was evident in specimens from the coloured ethnic "normal" subgroup. Gastric aspirate nitrite concentrations did not correlate with salivary values. The presence of microorganisms in gastric aspirates was shown to be pH dependent. Gastric aspirates with a pH &lt; 2,0 were sterile, below pH 4,0 only acidophilic bacteria survived, whereas above pH 4,0, numerous species, predominantly members of the oral microflora, were isolated. The mean mutagenicity ratio of the gastric aspirates from the carcinoma patients was found to be significantly higher than that found for the control group. There was a positive correlation between the mutagenicity ratios of all the gastric specimens and pH with a maximum at a pH value of approximately 6,0.

<p><em>Helicobacter pylori </em>is a bacterial infection of the stomach lining known to cause ulcers and stomach cancer This infection has become a major concern of Indigenous peoples living in the Northwest Territories, where <em>H. pylori </em>infection and stomach cancer are more prevalent relative to much of southern Canada and the United States. I joined the Canadian North <em>Helicobacter pylori</em> (CAN<em>Help</em>) Working Group in 2010 to conduct participant observation in the Aklavik <em>H. pylori </em>Project (AHPP) and identify ways that ethnography can be integrated into the ongoing multi-pronged research that incorporates epidemiology, microbiology, gastroenterology, knowledge translation, and the development of public health policy.</p> <p>Between September, 2011 and June, 2012, I lived as a participant observer in Aklavik. I led an epidemiological study of the incidence and re-infection of <em>H. pylori </em>infection. I examined how different risk perceptions emerge from processes of “making sense” of <em>H. pylori </em>as a “pathogen” or as a “contaminant” and described how these different constructions influence people’s behaviours. Ethnography, in this way, can make visible the lenses through which different groups of actors perceive, experience, and react to <em>H. pylori </em>infection. The recognition that the social inequities most strongly associated with <em>H. pylori </em>infection and re-infection that exist today are the result of Aklavik’s colonial history is one example of a space in which different lenses can be brought into a shared focus. From such shared understandings, consensus knowledge can be built collaboratively between outside researchers and Indigenous Arctic communities in an ongoing, and community-driven, research project. Furthermore, I critically examined the definition and use of the “household” as a level-unit of risk assessment and have outlined steps for assessing possible risk factors as these are distributed across multi-household extended kin groups that can be identified and followed in long-term research.</p> / Doctor of Social Science

Chu Wai Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 87-96). / Abstracts in English and Chinese. / Acknowledgments --- p.ii / Publication --- p.iii / List of Abbreviations --- p.iv / List of Tables --- p.v / List of Figures --- p.vi / Abstract --- p.vii / 摘要 --- p.x / Table of Contents --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Epidemiology of gastric cancer --- p.1 / Chapter 1.2 --- Risk factors associated with gastric cancer --- p.7 / Chapter 1.3 --- Prevention of Gastric Cancer --- p.9 / Chapter 1.4 --- H. pylori eradication and gastric cancer development --- p.11 / Chapter 1.5 --- Non-steroidal anti-inflammatory drugs and gastric cancer prevention --- p.13 / Chapter 1.6 --- COX-2 independent pathway --- p.14 / Chapter 1.7 --- Animal model of gastric cancer --- p.15 / Chapter 1.8 --- Microarray system --- p.16 / Chapter 1.9 --- Hypothesis --- p.18 / Chapter 1.10 --- Aim of study --- p.19 / Chapter Chapter 2 --- Chemoprevention of gastric cancer by celecoxib --- p.20 / Chapter 2.1 --- Introduction --- p.20 / Chapter 2.2 --- Material and Methods --- p.22 / Chapter 2.2.1 --- Animals --- p.22 / Chapter 2.2.2 --- Chemicals --- p.22 / Chapter 2.2.3 --- Study design --- p.23 / Chapter 2.2.4 --- Cell Culture --- p.24 / Chapter 2.2.5 --- Celecoxib treatment --- p.24 / Chapter 2.2.6 --- Cell proliferation assay --- p.25 / Chapter 2.3 --- Results --- p.26 / Chapter 2.3.1 --- Chemoprevention of gastric cancer by celecoxib in rats --- p.26 / Chapter 2.3.2 --- Effects of celecoxib on growth of human gastric cancer cells --- p.29 / Chapter 2.4 --- Discussion --- p.30 / Chapter 2.4.1 --- MNNG induced gastric cancer effectively --- p.30 / Chapter 2.4.2 --- Celecoxib significantly suppressed gastric carcinogenesis in rats --- p.31 / Chapter 2.4.3 --- Celecoxib inhibited the growth of MKN 45 in a concentration-dependent manner --- p.31 / Chapter 2.4.4 --- Celecoxib may exert its anti-tumor property through COX independent pathway --- p.32 / Chapter Chapter 3 --- Gene expression profiles of celecoxib treated rat gastric tumor and human gastric cells --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Material and Methods --- p.34 / Chapter 3.2.1 --- RNA extraction --- p.34 / Chapter 3.2.2 --- Target preparation and Array hybridization --- p.35 / Chapter 3.2.3 --- Post-hybridization processing and Scanning --- p.36 / Chapter 3.2.4 --- Microarray data analysis --- p.36 / Chapter 3.2.5 --- Quantitative RT-PCR --- p.37 / Chapter 3.3 --- Results --- p.39 / Chapter 3.3.1 --- Gene expression profiles of rat gastric tumors --- p.39 / Chapter 3.3.1.1 --- Genes differentially expressed in MNNG induced gastric tumors --- p.39 / Chapter 3.3.1.2 --- Genes differentially expressed in celecoxib treated group --- p.42 / Chapter 3.3.1.3 --- Mechanisms underlying chemoprevention of celecoxib --- p.43 / Chapter 3.3.2 --- Verification of gene expression by quantitative RT-PCR --- p.55 / Chapter 3.3.3 --- Confirmation of the gene expression profiles in human by quantitative RT-PCR --- p.59 / Chapter 3.4 --- Discussions --- p.63 / Chapter Chapter 4 --- Effects of celecoxib on Akt pathway in gastric cancer cells --- p.68 / Chapter 4.1 --- Introduction --- p.68 / Chapter 4.2 --- Material and methods --- p.72 / Chapter 4.2.1 --- Protein extraction --- p.72 / Chapter 4.2.2 --- Western blotting --- p.72 / Chapter 4.3 --- Results --- p.74 / Chapter 4.3.1 --- Expression of the Akt pathway after treatment with celecoxib --- p.74 / Chapter 4.4 --- Discussions --- p.78 / Chapter Chapter 5 --- Conclusion --- p.82 / References --- p.87