Yee-Hui Yeo | University of Oxford (original) (raw)

Papers by Yee-Hui Yeo

Gut, Jan 26, 2016

To determine the optimal regimen of different first-line Helicobacter pylori eradication therapie... more To determine the optimal regimen of different first-line Helicobacter pylori eradication therapies according to the clarithromycin resistance rate. Electronic search for articles published between January 2005 and April 2016. Randomised, controlled trials that reported the effectiveness of first-line eradication therapies in treatment-naïve adults were included. Two independent reviewers performed articles screening and data extraction. Network and traditional meta-analyses were conducted using the random effect model. Subgroup analyses were performed to determine the ranking of regimens in countries with high (>15%) and low (<15%) clarithromycin resistance. Data including adverse events and therapeutic cure rate were also extracted and analysed. 117 trials (totally 32 852 patients) for 17 H. pylori eradication regimens were eligible for inclusion. Compared with 7-day clarithromycin-based triple therapy, sequential therapy (ST) for 14 days had the highest effectiveness (OR=3.7...

BMC Gastroenterology, 2014

Hepatobiliary cystadenocarcinoma is a rare epithelial malignant neoplasm of the liver or extrahep... more Hepatobiliary cystadenocarcinoma is a rare epithelial malignant neoplasm of the liver or extrahepatic bile ducts. Early diagnosis of hepatobiliary cystadenocarcinoma is difficult because of its asymptomatic features and rarity. Moreover, the molecular pathogenesis of hepatobiliary cystadenocarcinoma remains unclear. Herein, we described a case of hepatobiliary cystadenocarcinoma in female with chronic hepatitis B and repeated hepatolithiasis. A 65-year-old woman with medical history of latent hepatitis B virus infection, repeated choledocholisthiasis, and cholecystitis was admitted due to a heterogeneous cystic mass (5.6 cm × 4 cm) shown on abdominal ultrasonography during regular physical checkup. The patient complained about irregular bowel movements with intermittent diarrhea for two months before presentation. Computed tomography (CT) disclosed a multiloculated cystic lesion in the left hepatic lobe with the presence of intraductal stones and dilatation of intrahepatic ducts. Histological results obtained from left lobectomy specimens showed hepatobiliary cystadenocarcinoma without accompanied mesenchymal stroma. Notably, hepatobiliary cystadenocarcinoma without mesenchymal stroma seldom occurs in women and is usually associated with poor prognosis. We present the rare findings in this patient and suggest that chronic inflammatory insults in the intrahepatic bile ducts might shed light on the cystadenocarcinogenesis.

PLoS ONE, 2014

The ability of cells to rapidly detect and react to alterations in their chemical environment, su... more The ability of cells to rapidly detect and react to alterations in their chemical environment, such as pH, ionic strength and redox potential, is essential for cell function and survival. We present here evidence that cells can respond to such environmental alterations by rapid induction of matriptase autoactivation. Specifically, we show that matriptase autoactivation can occur spontaneously at physiological pH, and is significantly enhanced by acidic pH, both in a cellfree system and in living cells. The acid-accelerated autoactivation can be attenuated by chloride, a property that may be part of a safety mechanism to prevent unregulated matriptase autoactivation. Additionally, the thio-redox balance of the environment also modulates matriptase autoactivation. Using the cell-free system, we show that matriptase autoactivation is suppressed by cytosolic reductive factors, with this cytosolic suppression being reverted by the addition of oxidizing agents. In living cells, we observed rapid induction of matriptase autoactivation upon exposure to toxic metal ions known to induce oxidative stress, including CoCl 2 and CdCl 2 . The metal-induced matriptase autoactivation is suppressed by Nacetylcysteine, supporting the putative role of altered cellular redox state in metal induced matriptase autoactivation. Furthermore, matriptase knockdown rendered cells more susceptible to CdCl 2 -induced cell death compared to control cells. This observation implies that the metal-induced matriptase autoactivation confers cells with the ability to survive exposure to toxic metals and/or oxidative stress. Our results suggest that matriptase can act as a cellular sensor of the chemical environment of the cell that allows the cell to respond to and protect itself from changes in the chemical milieu.

PLoS ONE, 2013

Background: Blood culture is viewed as the golden standard for the diagnosis of sepsis but suffer... more Background: Blood culture is viewed as the golden standard for the diagnosis of sepsis but suffers from low sensitivity and long turnaround time. LightCycler SeptiFast (LC-SF) is a real-time multiplex polymerase chain reaction test able to detect 25 common pathogens responsible for bloodstream infections within hours. We aim to assess the accuracy of LC-SF by systematically reviewing the published studies.

Journal of Histochemistry & Cytochemistry, 2014

Studies of human genetic disorders and mouse models reveal the important roles of matriptase in h... more Studies of human genetic disorders and mouse models reveal the important roles of matriptase in hair growth. Here, we investigate matriptase expression and zymogen activation in hair follicles. We show: 1) layer-dependent distribution patterns, with much higher matriptase expression in cells of the outer root sheath and matrix cells of the hair bulb than in cells of the inner root sheath; 2) cycle-dependent expression patterns, with matriptase expressed in the anagen and catagen phases of the hair lifecycle, but not in the telogen phase; 3) reduced expression of the matriptase inhibitor, HAI-1, in the catagen phase, suggesting increased proteolytic activity in this phase; and 4) definitive matriptase zymogen activation patterns, with the highest matriptase activation observed in matrix cells and outer root sheath cells in the isthmus/bulge region. In sebaceous glands, matriptase is highly expressed in basal and ductal cells, with much lower expression in the differentiated, lipid-filled cells of the interior. We also show that matriptase potently activates hepatocyte growth factor (HGF) in vitro, and that the HGF receptor, c-Met, is co-expressed in those cells that express activated matriptase. Our observations suggest that the matriptase-HGF-c-MET pathway has the potential to be engaged, primarily in proliferative cells rather than terminally differentiated epithelial cells of the human pilosebaceous unit. (J Histochem Cytochem 62:50-59, 2014)

Critical Care Medicine, 2014

Hemorrhage is responsible for most deaths that occur during the first few hours after trauma. Ani... more Hemorrhage is responsible for most deaths that occur during the first few hours after trauma. Animal models of trauma have shown that restricting fluid administration can reduce the risk of death; however, studies in patients are difficult to conduct due to logistical and ethical problems. To maximize the value of the existing evidence, we performed a meta-analysis to compare liberal versus restricted fluid resuscitation strategies in trauma patients. Medline and Embase were systemically searched from inception to February 2013. We selected randomized controlled trials and observational studies that compared different fluid administration strategies in trauma patients. There were no restrictions for language, population, or publication year. Four randomized controlled trials and seven observational studies were identified from 1,106 references. One of the randomized controlled trials suffered from a high protocol violation rate and was excluded from the final analysis. The quantitative synthesis indicated that liberal fluid resuscitation strategies might be associated with higher mortality than restricted fluid strategies, both in randomized controlled trials (risk ratio, 1.25; 95% CI, 1.01-1.55; three trials; I(2), 0) and observational studies (odds ratio, 1.14; 95% CI, 1.01-1.28; seven studies; I(2), 21.4%). When only adjusted odds ratios were pooled for observational studies, odds for mortality with liberal fluid resuscitation strategies increased (odds ratio, 1.19; 95% CI, 1.02-1.38; six studies; I(2), 26.3%). Current evidence indicates that initial liberal fluid resuscitation strategies may be associated with higher mortality in injured patients. However, available studies are subject to a high risk of selection bias and clinical heterogeneity. This result should be interpreted with great caution.

Clinical Neuropathology, 2012

Pilocytic astrocytoma (PA) is the most common pediatric tumor, with the vast majority being benig... more Pilocytic astrocytoma (PA) is the most common pediatric tumor, with the vast majority being benign (WHO Grade I). Herein, we present a rare sporadic (not radiation- or NF1-associated) anaplastic PA arising from the cerebellum of an adult patient. The diagnosis was based on the coexistence of classic PA and more cellular foci, associated with both tumor necrosis and up to 27 mitoses per 10 high power fields. Based on these features, the tumor was felt to be equivalent in biological behavior to that of a WHO Grade III astrocytoma. Additional genetic studies revealed the presence of a BRAF V600E mutation. In comparison to the foci of classic PA, the malignant component showed increased p53 protein expression, decreased p16 protein expression, and hemizygous p16 gene deletion by FISH analysis. This case provides additional support for the concept of anaplastic transformation in PA and further elucidates the possible molecular pathways associated with malignant progression.

Gut, Jan 26, 2016

To determine the optimal regimen of different first-line Helicobacter pylori eradication therapie... more To determine the optimal regimen of different first-line Helicobacter pylori eradication therapies according to the clarithromycin resistance rate. Electronic search for articles published between January 2005 and April 2016. Randomised, controlled trials that reported the effectiveness of first-line eradication therapies in treatment-naïve adults were included. Two independent reviewers performed articles screening and data extraction. Network and traditional meta-analyses were conducted using the random effect model. Subgroup analyses were performed to determine the ranking of regimens in countries with high (>15%) and low (<15%) clarithromycin resistance. Data including adverse events and therapeutic cure rate were also extracted and analysed. 117 trials (totally 32 852 patients) for 17 H. pylori eradication regimens were eligible for inclusion. Compared with 7-day clarithromycin-based triple therapy, sequential therapy (ST) for 14 days had the highest effectiveness (OR=3.7...

BMC Gastroenterology, 2014

Hepatobiliary cystadenocarcinoma is a rare epithelial malignant neoplasm of the liver or extrahep... more Hepatobiliary cystadenocarcinoma is a rare epithelial malignant neoplasm of the liver or extrahepatic bile ducts. Early diagnosis of hepatobiliary cystadenocarcinoma is difficult because of its asymptomatic features and rarity. Moreover, the molecular pathogenesis of hepatobiliary cystadenocarcinoma remains unclear. Herein, we described a case of hepatobiliary cystadenocarcinoma in female with chronic hepatitis B and repeated hepatolithiasis. A 65-year-old woman with medical history of latent hepatitis B virus infection, repeated choledocholisthiasis, and cholecystitis was admitted due to a heterogeneous cystic mass (5.6 cm × 4 cm) shown on abdominal ultrasonography during regular physical checkup. The patient complained about irregular bowel movements with intermittent diarrhea for two months before presentation. Computed tomography (CT) disclosed a multiloculated cystic lesion in the left hepatic lobe with the presence of intraductal stones and dilatation of intrahepatic ducts. Histological results obtained from left lobectomy specimens showed hepatobiliary cystadenocarcinoma without accompanied mesenchymal stroma. Notably, hepatobiliary cystadenocarcinoma without mesenchymal stroma seldom occurs in women and is usually associated with poor prognosis. We present the rare findings in this patient and suggest that chronic inflammatory insults in the intrahepatic bile ducts might shed light on the cystadenocarcinogenesis.

PLoS ONE, 2014

The ability of cells to rapidly detect and react to alterations in their chemical environment, su... more The ability of cells to rapidly detect and react to alterations in their chemical environment, such as pH, ionic strength and redox potential, is essential for cell function and survival. We present here evidence that cells can respond to such environmental alterations by rapid induction of matriptase autoactivation. Specifically, we show that matriptase autoactivation can occur spontaneously at physiological pH, and is significantly enhanced by acidic pH, both in a cellfree system and in living cells. The acid-accelerated autoactivation can be attenuated by chloride, a property that may be part of a safety mechanism to prevent unregulated matriptase autoactivation. Additionally, the thio-redox balance of the environment also modulates matriptase autoactivation. Using the cell-free system, we show that matriptase autoactivation is suppressed by cytosolic reductive factors, with this cytosolic suppression being reverted by the addition of oxidizing agents. In living cells, we observed rapid induction of matriptase autoactivation upon exposure to toxic metal ions known to induce oxidative stress, including CoCl 2 and CdCl 2 . The metal-induced matriptase autoactivation is suppressed by Nacetylcysteine, supporting the putative role of altered cellular redox state in metal induced matriptase autoactivation. Furthermore, matriptase knockdown rendered cells more susceptible to CdCl 2 -induced cell death compared to control cells. This observation implies that the metal-induced matriptase autoactivation confers cells with the ability to survive exposure to toxic metals and/or oxidative stress. Our results suggest that matriptase can act as a cellular sensor of the chemical environment of the cell that allows the cell to respond to and protect itself from changes in the chemical milieu.

PLoS ONE, 2013

Background: Blood culture is viewed as the golden standard for the diagnosis of sepsis but suffer... more Background: Blood culture is viewed as the golden standard for the diagnosis of sepsis but suffers from low sensitivity and long turnaround time. LightCycler SeptiFast (LC-SF) is a real-time multiplex polymerase chain reaction test able to detect 25 common pathogens responsible for bloodstream infections within hours. We aim to assess the accuracy of LC-SF by systematically reviewing the published studies.

Journal of Histochemistry & Cytochemistry, 2014

Studies of human genetic disorders and mouse models reveal the important roles of matriptase in h... more Studies of human genetic disorders and mouse models reveal the important roles of matriptase in hair growth. Here, we investigate matriptase expression and zymogen activation in hair follicles. We show: 1) layer-dependent distribution patterns, with much higher matriptase expression in cells of the outer root sheath and matrix cells of the hair bulb than in cells of the inner root sheath; 2) cycle-dependent expression patterns, with matriptase expressed in the anagen and catagen phases of the hair lifecycle, but not in the telogen phase; 3) reduced expression of the matriptase inhibitor, HAI-1, in the catagen phase, suggesting increased proteolytic activity in this phase; and 4) definitive matriptase zymogen activation patterns, with the highest matriptase activation observed in matrix cells and outer root sheath cells in the isthmus/bulge region. In sebaceous glands, matriptase is highly expressed in basal and ductal cells, with much lower expression in the differentiated, lipid-filled cells of the interior. We also show that matriptase potently activates hepatocyte growth factor (HGF) in vitro, and that the HGF receptor, c-Met, is co-expressed in those cells that express activated matriptase. Our observations suggest that the matriptase-HGF-c-MET pathway has the potential to be engaged, primarily in proliferative cells rather than terminally differentiated epithelial cells of the human pilosebaceous unit. (J Histochem Cytochem 62:50-59, 2014)

Critical Care Medicine, 2014

Hemorrhage is responsible for most deaths that occur during the first few hours after trauma. Ani... more Hemorrhage is responsible for most deaths that occur during the first few hours after trauma. Animal models of trauma have shown that restricting fluid administration can reduce the risk of death; however, studies in patients are difficult to conduct due to logistical and ethical problems. To maximize the value of the existing evidence, we performed a meta-analysis to compare liberal versus restricted fluid resuscitation strategies in trauma patients. Medline and Embase were systemically searched from inception to February 2013. We selected randomized controlled trials and observational studies that compared different fluid administration strategies in trauma patients. There were no restrictions for language, population, or publication year. Four randomized controlled trials and seven observational studies were identified from 1,106 references. One of the randomized controlled trials suffered from a high protocol violation rate and was excluded from the final analysis. The quantitative synthesis indicated that liberal fluid resuscitation strategies might be associated with higher mortality than restricted fluid strategies, both in randomized controlled trials (risk ratio, 1.25; 95% CI, 1.01-1.55; three trials; I(2), 0) and observational studies (odds ratio, 1.14; 95% CI, 1.01-1.28; seven studies; I(2), 21.4%). When only adjusted odds ratios were pooled for observational studies, odds for mortality with liberal fluid resuscitation strategies increased (odds ratio, 1.19; 95% CI, 1.02-1.38; six studies; I(2), 26.3%). Current evidence indicates that initial liberal fluid resuscitation strategies may be associated with higher mortality in injured patients. However, available studies are subject to a high risk of selection bias and clinical heterogeneity. This result should be interpreted with great caution.

Clinical Neuropathology, 2012

Pilocytic astrocytoma (PA) is the most common pediatric tumor, with the vast majority being benig... more Pilocytic astrocytoma (PA) is the most common pediatric tumor, with the vast majority being benign (WHO Grade I). Herein, we present a rare sporadic (not radiation- or NF1-associated) anaplastic PA arising from the cerebellum of an adult patient. The diagnosis was based on the coexistence of classic PA and more cellular foci, associated with both tumor necrosis and up to 27 mitoses per 10 high power fields. Based on these features, the tumor was felt to be equivalent in biological behavior to that of a WHO Grade III astrocytoma. Additional genetic studies revealed the presence of a BRAF V600E mutation. In comparison to the foci of classic PA, the malignant component showed increased p53 protein expression, decreased p16 protein expression, and hemizygous p16 gene deletion by FISH analysis. This case provides additional support for the concept of anaplastic transformation in PA and further elucidates the possible molecular pathways associated with malignant progression.