Samuel So - Academia.edu (original) (raw)

Papers by Samuel So

PubMed, Jul 31, 2009

Chronic hepatitis B in the Asian and Pacific Islander (API) population is among our nation's grea... more Chronic hepatitis B in the Asian and Pacific Islander (API) population is among our nation's greatest ethnic and racial health disparities. Despite comprising 4.3% of the population, API make up a disproportionate half of the 1.2-2 million Americans living with chronic hepatitis B. As many as two-thirds of API are not aware of their infection because they have not been tested. This lack of knowledge prevents them from undergoing life-saving liver cancer screening and potential treatment. Likewise, those not protected are unaware that they should be vaccinated. Instead, there is a pervasive lack of awareness among API and healthcare providers. New concerted public health actions are needed to eliminate this major health disparity.

Scientific Reports, 2019

Hepatitis B virus (HBV) infection has a global reach with high prevalence in resource-limited are... more Hepatitis B virus (HBV) infection has a global reach with high prevalence in resource-limited areas like China and Africa. HBV patients in these areas have limited access to the currently used, costly HBV assays, which are performed in centralized clinical laboratories using single-plexed assays with bulky and expensive instruments. We aim to overcome these limitations by developing a simple and affordable HBV diagnostic platform to allow for timelier diagnosis and intervention of HBV infection. Using giant magnetoresistive (GMR) biosensor chips, we developed an automated and multiplexed quantitative platform for the measurement of a panel of HBV serology markers, including HBV “e” antigen (HBeAg), HBV surface antigen (HBsAg), and the antibody against HBsAg (anti-HBs). Our assay platform was able to detect each HBV marker with high specificity and sensitivity (with three orders of magnitude in dynamic range for each marker). Blinded analysis of HBV patient sera showed excellent corr...

Journal of Communication in Healthcare, 2011

ABSTRACT Hepatitis B and its resultant liver cancer are leading causes of morbidity and mortality... more ABSTRACT Hepatitis B and its resultant liver cancer are leading causes of morbidity and mortality among Asians and Pacific Islanders (API). In the United States, the disproportionately high prevalence rates of these diseases in the API population constitute some of the nation's greatest health disparities. However, public awareness remains poor and public health efforts need to be strengthened. The Jade Ribbon Campaign is a culturally and linguistically targeted, evidence-based model programme for health communication to improve awareness among API. This model demonstrates that cultural competency does not simply entail a straightforward transfer of ideas, strategies, and materials from one culture or language to another. Rather, it requires a deep understanding of a target community, a multi-faceted approach, and the buy-in of diverse stakeholders, many of whom may not be in health-care-related fields. This paper discusses the Jade Ribbon Campaign as a model programme to illustrate the strategies and components for developing a successful, culturally competent health awareness campaign.

Background and Aim: Vietnam’s high burden of liver cancer is largely attributable to the high pre... more Background and Aim: Vietnam’s high burden of liver cancer is largely attributable to the high prevalence of chronic hepatitis B virus infection (HBV). Infection at birth due to mother-to-child (MTC) transmission is the most common cause of chronic HBV in Vietnam and increases the risk of liver cancer later in life. This study was undertaken to examine the knowledge, attitudes, and practices of pregnant women and mothers in Vietnam concerning HBV prevention and immunization. Methods: A cross-sectional study was conducted in Quang Ninh and Hoa Binh provinces in 2017. A pre-designed questionnaire was administered to women when they received care at primary and tertiary maternal health clinics. Correct responses were summarized as knowledge scores. Data was analyzed using a multivariable regression model across participant demographics. Results: Among the 404 women surveyed, 57.6% were pregnant and 42.4% were postpartum. Despite 73.5% of participants reporting having received informatio...

<b>Copyright information:</b>Taken from "Mutations of in gastric adenocarcinoma&... more <b>Copyright information:</b>Taken from "Mutations of in gastric adenocarcinoma"BMC Cancer 2005;5():29-29.Published online 23 Mar 2005PMCID:PMC1079799.Copyright © 2005 Li et al; licensee BioMed Central Ltd. Site of mutation is denoted by the red arrow. (b) Sequence chromatogram of the corresponding normal mucosa from the same case showing the absence of mutation (red arrow), and thus confirming the somatic nature of the mutation.

Biomarker Insights, 2008

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Effective t... more Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Effective treatment of HCC patients is hampered by the lack of sensitive and specific diagnostic markers of HCC. Alpha-fetoprotein (AFP), the currently used HCC marker, misses 30%-50% of HCC patients, who therefore remain undiagnosed and untreated. In order to identify novel diagnostic markers that can be used individually or in combination with AFP, we used an antibody array platform to detect the levels of candidate proteins in the plasma of HCC patients (n = 48) and patients with chronic hepatitis B or C viral infections (n = 19) (both of which are the major risk factors of HCC). We identified 7 proteins that significantly differentiate HCC patients from hepatitis patients (p < 0.05) (AFP, CTNNB, CSF1, SELL, IGFBP6, IL6R, and VCAM1). Importantly, we also identified 8 proteins that significantly differentiate HCC patients with ‘normal’ levels of AFP (<20 ng/ml) from hepatitis patients (p &l...

Asian Pacific Journal of Cancer Prevention, 2013

World journal of gastroenterology : WJG, Jan 14, 2015

To investigate physicians' knowledge including chronic hepatitis B (CHB) diagnosis, screening... more To investigate physicians' knowledge including chronic hepatitis B (CHB) diagnosis, screening, and management in various stages of their training. A voluntary 20-question survey was administered in Santa Clara County, CA where Asian and Pacific Islanders (API) account for a third of the population. Among the 219 physician participants, there were 63 interns, 60 second-year residents, 26 chief residents and 70 attending physicians. The survey asked questions regarding respondents' demographics, general hepatitis B virus knowledge questions (i.e., transmission, prevalence, diagnostic testing, prevention, and treatment options), as well as, self-reported practice behavior and confidence in knowledge. Knowledge about screening and managing patients with CHB was poor: only 24% identified the correct tests to screen for CHB, 13% knew the next steps for patients testing positive for CHB, 18% knew the high prevalence rate among API, and 31% knew how to screen for liver cancer. Wald ...

BMC Cancer, 2015

Background: Granulin-epithelin precursor (GEP), a secretory growth factor, demonstrated overexpre... more Background: Granulin-epithelin precursor (GEP), a secretory growth factor, demonstrated overexpression in various human cancers, however, mechanism remain elusive. Primary liver cancer, hepatocellular carcinoma (HCC), ranks the second in cancer-related death globally. GEP controlled growth, invasion, metastasis and chemo-resistance in liver cancer. Noted that GEP gene locates at 17q21 and the region has been frequently reported to be amplified in subset of HCC. The study aims to investigate if copy number gain would associate with GEP overexpression. Methods: Quantitative Microsatellite Analysis (QuMA) was used to quantify the GEP DNA copy number, and fluorescent in situ hybridization (FISH) was performed to consolidate the amplification status. GEP gene copy number, mRNA expression level and clinico-pathological features were analyzed. Results: GEP DNA copy number determined by QuMA corroborated well with the FISH data, and the gene copy number correlated with the expression levels (n = 60, r = 0.331, P = 0.010). Gain of GEP copy number was observed in 20% (12/60) HCC and associated with hepatitis B virus infection status (P = 0.015). In HCC with increased GEP copy number, tight association between GEP DNA and mRNA levels were observed (n = 12, r = 0.664, P = 0.019). Conclusions: Gain of the GEP gene copy number was observed in 20% HCC and the frequency comparable to literatures reported on the chromosome region 17q. Increased gene copy number contributed to GEP overexpression in subset of HCC.

Cancer Research, 2013

Background: Glypican-3 (GPC3) is a cell-surface protein which is over-expressed in more than 50% ... more Background: Glypican-3 (GPC3) is a cell-surface protein which is over-expressed in more than 50% of hepatocellular carcinoma (HCC) patients, but is negligibly expressed in normal livers, benign liver lesions, and tissues adjacent to HCC. GPC3 is therefore a potential molecular target for HCC diagnosis. Methods: Two radiotracers, 64Cu-DOTA-GPC3 and 89Zr-DFO-GPC3, were synthesized based on the human anti-GPC3 monoclonal antibody (MAb clone 1G12). These radiotracers were used for positron emission tomography (PET) imaging of subcutaneous or orthotopic HCC xenografts in nude mice, generated from HCC cell lines expressing high (HepG2), moderate (Hep3B), or low (PLC/PRF/5) levels of GPC3. Biodistribution analysis and tumor-to-liver ratios were calculated to assess the performance and specificity of these radiotracers. Results: The anti-GPC3 MAb showed high binding affinity to recombinant human GPC3 protein in vitro (KD = 0.40 ± 0.04 nM), and specifically identified HCC cell lines and human specimens with high GPC3 expression. In vivo, 64Cu-DOTA-GPC3 showed significantly higher uptake in HepG2 xenografts (17.05 ± 1.31% ID/g) compared with non-specific 18F-fluoro-deoxy-glucose (18F-FDG) (3.17 ± 0.59% ID/g), and the non-targeting 64Cu-DOTA-IgG (5.10 ± 1.27% ID/g) at 72 h post-injection (p.i.) (p Conclusion: We demonstrate that anti-GPC3 MAb-based PET probes can detect GPC3-positive HCCs in subcutaneous and orthotopic animal models. Especially, 89Zr-DFO-GPC3 is a promising probe and clinically useful probe for the specific imaging of GPC3-positive HCCs. Citation Format: Xiaoyang Yang, Susan Hoppmann, Hongguang Liu, Mark Allegretta, Mei-Sze Chua, Zhen Cheng, Samuel So. Molecular imaging of hepatocellular carcinoma using radiolabeled monoclonal antibody PET probes targeting glypican-3. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 715. doi:10.1158/1538-7445.AM2013-715

Transplantation, 1991

Prior to 1975 patients with systemic lupus erythematosus were generally not considered candidates... more Prior to 1975 patients with systemic lupus erythematosus were generally not considered candidates for renal transplantation because of concern that immune complex deposition would rapidly destroy the allograft. However, recent evidence suggests that good patient ...

Journal of Obstetric, Gynecologic, & Neonatal Nursing, 2012

Journal of Community Health, 2010

International Journal of Public Health, 2011

Incomplete hepatitis B virus (HBV) vaccine coverage and poor HBV-related knowledge in China leave... more Incomplete hepatitis B virus (HBV) vaccine coverage and poor HBV-related knowledge in China leave millions of children unprotected from this life-threatening infection. To address these gaps, a pilot program for HBV education and vaccination was launched in rural China. In 2006, public and private organizations in the US and China collaborated to provide HBV education and vaccination to 55,000 school-age children in the remote, highly HBV-endemic area of Qinghai Province. The impact of the educational program on HBV-related knowledge was evaluated among more than 2,800 elementary school students. Between September 2006 and March 2007, the three-shot hepatitis B vaccine series was administered to 54,680 students, with a completion rate of 99.4%. From low pre-existing knowledge levels, classroom educational sessions statistically significantly increased knowledge about HBV risks, symptoms, transmission, and prevention. This program offers an effective and sustainable model for HBV catch-up vaccination and education that can be replicated throughout China, as well as in other underserved HBV-endemic regions, as a strategy to reduce chronic HBV infection, liver failure, and liver cancer.

BMC Public Health, 2010

Background Chronic hepatitis B virus (HBV) infection is the leading cause of liver disease and li... more Background Chronic hepatitis B virus (HBV) infection is the leading cause of liver disease and liver cancer and a major source of health-related discrimination in China. To better target HBV detection and prevention programs, it is necessary to assess existing HBV knowledge, educational resources, reporting, and preventive practices, particularly among those health professionals who would be responsible for implementing such programs. Methods At the China National Conference on the Prevention and Control of Viral Hepatitis on April 26-29, 2004, the Asian Liver Center at Stanford University partnered with the China Foundation for Hepatitis Prevention and Control to distribute a voluntary written questionnaire to Chinese healthcare and public health professionals from regional and provincial Chinese Centers for Disease Control and Prevention, health departments, and medical centers. Correct responses to survey questions were summed into a total knowledge score, and multivariate linear...

Journal of Immigrant and Minority Health, 2007

Importance - Cancer is the second leading cause of death worldwide. Current estimates on the burd... more Importance - Cancer is the second leading cause of death worldwide. Current estimates on the burden of cancer are needed for cancer control planning. Objective - To estimate mortality, incidence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs) for 32 cancers in 195 countries and territories from 1990 to 2015. Evidence Review - Cancer mortality was estimated using vital registration system data, cancer registry incidence data (transformed to mortality estimates using separately estimated mortality to incidence [MI] ratios), and verbal autopsy data. Cancer incidence was calculated by dividing mortality estimates through the modeled MI ratios. To calculate cancer prevalence, MI ratios were used to model survival. To calculate YLDs, prevalence estimates were multiplied by disability weights. The YLLs were estimated by multiplying age-specific cancer deaths by the reference life expectancy. DALYs were estimated as the sum of YLDs ...

International Journal of Environmental Research and Public Health, 2021

Background: Building capacity in hepatitis B virus prevention and management for medical students... more Background: Building capacity in hepatitis B virus prevention and management for medical students and health professionals is one of the pillars of the national viral hepatitis control strategy. Methods: A cross-sectional study was conducted at eight medical universities from the northern, central and southern regions of the country between May and November 2020 using a systematic random sampling technique. Results: Among 2000 participants, 84.2% reported they had been tested for hepatitis B and 83.9% had received the hepatitis B vaccine. The mean knowledge, attitude, practice score was 40.2 out of 54 (74.4%) with only 19.9% of the study participants obtaining a good score. In multivariate analysis, fifth year students, students from central universities, students who had tested positive for hepatitis B and students who had received hepatitis B vaccine or had encountered patients with chronic hepatitis B had significantly higher knowledge score (p < 0.05). The study showed lack o...

BACKGROUND An estimated 862,000 to 2.4 million people have chronic hepatitis B infection (CHB). L... more BACKGROUND An estimated 862,000 to 2.4 million people have chronic hepatitis B infection (CHB). Left undiagnosed and untreated CHB increases risk of death from liver cirrhosis or liver cancer. Hepatitis B screening is recommended for pregnant women and populations with increased CHB risk, but diagnosis rates remain low with only 33% of people with CHB aware of their infection.. This study aimed to assess the cost-effectiveness of universal adult screening for CHB. METHODS We used a Markov model to calculate the costs, population health impact and cost-effectiveness of one-time universal screening and CHB monitoring and treatment compared to current practice. Sensitivity analysis was performed on model parameters to identify thresholds for cost-savings or cost-effectiveness based on willinness-to-pay of $50,000/QALY . The analysis assumed testing would be performed during routine healthcare visits, and generic tenofovir or entecavir would be dispensed for treatment. Testing costs wer...