1.BRIEF HYPOXIA PRECEDING E. COLI BACTEREMIA DOWNREGULATES HEPATIC TNF-α PRODUCTION
Zhoumou CHEN ; Bingyin SHI ; Subbash TODI ; Cheryl JOHANNS ; M. GEORGE ;
Journal of Pharmaceutical Analysis 1999;11(1):40-44
Hepatic TNF-α production following gram-negative bacteremia or hypovolemic shock predisposes to acute lung injury. However, TNF-α expression may be modified by the manner in which the hepatic O2 supply is reduced and equally important, its timing relative to bacteremia. Brief secondary hypoxic stress of buffer-perfused rat livers downregulates E. Coli (EC)-induced TNF-α expression whereas low-flow ischemia preceding EC increases subsequent TNF-α production owing to reactive O2 species (ROS). Here we determined whether 30 min of constant-flow hypoxia preceding 109 intraportal EC likewise increases antigenic and bioactive TNF-α protein concentrations during reoxygenation via production of ROS. Multiple groups (n=38) were studied over 180 minutes, circulation antigenic TNF-α decreased in H/R+EC vs. EC controls (1 939±640 vs. 12 407±2 476 μg/L at t=180 min; P<0.01, along with TNF-α bioactivity). TNF-α protein were not restored to control levels in ALLO+H/R+EC. Thus, EC-induced hepatic TNF-α production and export is strongly O2-dependent in intact liver regardless of the generation of ROS or the sequence of bacteremia and modest hypoxic stress.
2.A family cluster of nitrite poisoning, Suzhou City, Jiangsu Province, China, 2013
Wang Ruiping ; Teng Chen-gang ; Zhang Ning ; Zhang Jun ; Conway George
Western Pacific Surveillance and Response 2013;4(3):33-36
Background:In April 2013, a hospital in Suzhou City notified authorities of a patient with nitrite poisoning with two other family members who had similar toxic symptoms five days prior. We investigated the event to identify the cause, source and possible route of contamination.Methods:A case was defined as any person living in the Yang Shan Hua Yuan community who had been diagnosed with cyanoderma and food poisoning symptoms from 15 to 25 April 2013. Active case finding was conducted by interviewing community residents and reviewing medical records from local clinics; information was then retrospectively collected on the patient’s food history, cooking procedures and food sources.Results:We identified three nitrite poisoning cases, one male and two females, from the same family. The time between dinner and onset of illness was less than an a hour. A retrospective survey showed that a substance presumed to be sugar mixed with asparagus on 17 April and with stir-fried asparagus on 21 April was the suspected contaminant. The presumed sugar came from a clean-up of a neighbouring rental house. Nitrite was detected in a vomitus sample, the sugar substance and two leftover food samples.Conclusion:This family cluster of nitrite poisoning resulted from the mistaken use of nitrite as sugar to cook dishes. We recommend that sodium nitrite be dyed a bright colour to prevent such a mistake and that health departments strengthen food hygiene education to alert people about the danger of eating unidentified food from an unknown source.
4.The independent effect of exercise on biopsy-proven non-alcoholic fatty liver disease: A systematic review
George CHEN ; Bubu BANINI ; Albert DO ; Joseph K. LIM
Clinical and Molecular Hepatology 2023;29(Suppl):S319-S332
Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Although previous studies have demonstrated that exercise independently reduces hepatic steatosis measured by imaging modalities in NAFLD, the effect of exercise on histological endpoints remains unclear. We aimed to conduct a systematic review of the independent effect of exercise on hepatic steatosis, steatohepatitis, and liver fibrosis as measured by histological assessment or non-invasive tests (NITs) in biopsy-proven NAFLD. A systematic literature search of PubMed, Embase, and Web of Science databases was performed using keywords related to exercise, NAFLD, and biopsy. Articles were selected based on the following inclusion criteria: (1) involved human subjects with biopsy-proven NAFLD, (2) analyzed the independent effect of exercise, (3) assessed changes in hepatic steatosis, steatohepatitis, or liver fibrosis via either histological evaluation or NITs, and (4) were original research studies. We identified a total of six studies that analyzed the independent effect of exercise on histological endpoints in biopsy-proven NAFLD. Two randomized controlled trials (RCTs) did not detect significant histological improvement following exercise interventions, while other non-randomized interventional studies showed that exercise reduces hepatocyte ballooning and liver fibrosis. In addition, five studies assessed NIT outcomes, collectively demonstrating that exercise improves hepatic steatosis measured by magnetic resonance imaging-based techniques but not serum biomarkers for steatohepatitis and liver fibrosis. Additional large RCTs and meta-analyses are warranted to investigate the independent effect of exercise on histological and clinical outcome endpoints in NAFLD.
5.Effects of enantiomers(R,R)-XY and(S,S)-XY on ocular blood flow in rabbits
Jie, PENG ; Yan-Hong, ZOU ; Wei, JIANG ; Xiao-Bin, JI ; Xin-Yu, CHEN ; Yi-Hua, ZHANG ; Si-Xun, PENG ; George C Y CHIOU
International Eye Science 2008;8(3):437-441
·AIM: To evaluate the effects of two series of enantiomers [(R, R)-XY-1 through (R, R)-XY-12 and (S,S)-XY-1 through (S, S)-XY-12] on ocular blood flow in rabbits.·METHODS; Colored microsphere technique was used for in vivo experiments to determine the ocular blood flow in various tissues of ocular hypertensive (40mmHg) rabbit eyes.·RESULTS; Of the twelve compounds of ( R, R)-XY series examined, four increased choroidal blood flow at 10g/L, 50uL instilled into eyes. All compounds of (S, S)-XY series were not effective on ocular blood flow.·CONCLUSION; Some compounds of (R, R)-XY series increased the ocular blood flow, which might be useful for the prevention and treatment of ocular blood flow related eye diseases. Among all twenty-four compounds, (R, R)-XY-1and (R, R)-XY-9 seem to be the most potent ones.KEYWORDS; ocular blood flow; ischemia; enantiomer
6.Effect of 5F from Pteris semipinnata on expression of Nr1d1 in HO-8910PM cell line.
Taiping HE ; Kefeng WU ; Yingnian LV ; Xianling GONG ; George Gong CHEN ; Nianci LIANG
China Journal of Chinese Materia Medica 2009;34(10):1268-1271
OBJECTIVETo investigate the effects of PsL5F (ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid, an extract from Pteris semipinnata L) on the expression of nuclear receptor subfamily 1, group D, member 1 (Nr1d1) in highly metastatic ovarian carcinoma HO-8910PM cells, and its mechanisms.
METHODMicroarray Chip was used to examine the level of Nr1d1 mRNA expression on HO-8910PM cells treated with PsL5F. Fluorescent quantitative real-time PCR assay and Western blot were performed to verify the effects of PsL5F on Nr1d1 mRNA and protein expression.
RESULTAfter 24 h treatment of 100 micromol x L(-1) PsL5F, the mRNA and protein levels of Nr1d1 in HO-8910PM cells were 35.34 +/- 1.07 and 7.71 +/- 0.43 times compared to those of control group (P < 0.01, P < 0.01), respectively.
CONCLUSIONPsL5F can up-regulate significantly the expression of Nr1d1 in HO-8910PM cells. Antitumor effects and its mechanisms of PsL5F in HO-8910PM cells may be involved in the up-regulation of Nr1d1 expression.
Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Line, Tumor ; Drug Screening Assays, Antitumor ; Female ; Gene Expression ; drug effects ; Humans ; Neoplasm Invasiveness ; Ovarian Neoplasms ; pathology ; Piperidones ; pharmacology ; Pteris ; chemistry ; RNA, Messenger ; drug effects ; metabolism
7.The inhibitory effect of tamoxifen on human dermal fibroblast-populated collagen lattices.
Dahai HU ; Xiongxiang ZHU ; Mingda XU ; Bi CHEN ; A H MARGARET ; W C GEORGE
Chinese Journal of Plastic Surgery 2002;18(3):160-162
OBJECTIVETo investigate the potential therapeutic effect of tamoxifen in treating abnormal skin scar contraction.
METHODSFibroblast-populated collagen lattices, which were made by embedding human dermal fibroblasts within type I collagen forming a three-dimensional culture system, were used as an invitro model. Then media either without or with addition of tamoxifen from 1 mumol/L to 50 mumol/L were added to the collagen lattices. Lattice areas were measured at intervals to assess the influence of tamoxifen on the lattice contraction. To visualize changes in the morphology and vitality of fibroblasts, MTT was added to the lattices.
RESULTSTamoxifen had an inhibitory effect on lattice contraction by a dose- and time-dependent pattern. 5 mumol/L or less of tamoxifen didn't show any influence on lattice contraction but 30 mumol/L or higher completely inhibited contraction. At intermediate concentrations from 10 mumol/L to 20 mumol/L the degree of lattice contraction was dose- and time-dependent, which was demonstrated by the reversibility of inhibition. Both the inhibition of contraction and the reversibility of inhibition appeared to correlate with changes in fibroblast morphology.
CONCLUSIONTamoxifen could inhibit the contraction of fibroblast-populated collagen lattices, indicating that tamoxifen may have potential effect on abnormal scar contraction in vivo.
Cicatrix ; drug therapy ; Collagen ; physiology ; Dose-Response Relationship, Drug ; Fibroblasts ; drug effects ; physiology ; Humans ; Skin ; cytology ; drug effects ; Tamoxifen ; pharmacology ; therapeutic use ; Time Factors
8.Risk factors and outcomes of uterine rupture in Singapore: Emerging trends.
Shu Qi TAN ; Li Houng CHEN ; Dhilshad Bte MUHD ABDUL QADIR ; Bernard SM CHERN ; George SH YEO
Annals of the Academy of Medicine, Singapore 2021;50(1):5-15
INTRODUCTION:
Uterine rupture is uncommon but has catastrophic implications on the pregnancy. A scarred uterus and abnormal placentation are known contributory factors. The aim of our study was to review the contributing factors, clinical presentation, complications and management of uterine rupture in our population in light of the changing nature of modern obstetric practices.
METHODS:
A retrospective observational study was conducted at KK Women's and Children's Hospital by studying proven cases of uterine rupture in the period between January 2003 and December 2014. These cases were analysed according to their past history, clinical presentation, complications, management and outcome.
RESULTS:
A total of 48 cases of proven uterine rupture were identified. The incidence of uterine rupture was 1 in 3,062 deliveries. The ratio of scarred uterus rupture to unscarred uterus rupture was approximately 3:1. The most common factor was previous lower segment caesarean section for the scarred group, followed by a history of laparoscopic myomectomy. Abdominal pain was the common clinical presentation in the antenatal period, while abnormal cardiotocography findings were the most common presentation in intrapartum rupture.
CONCLUSION
There is a notable shift in the trend of uterine rupture cases given the increasing use of laparoscopic myomectomy and elective caesarean sections. While ruptures from these cases were few, their presentation in the antenatal period calls for diligent monitoring with informed patient involvement in their pregnancy care.
9.A dimeric structure of PD-L1: functional units or evolutionary relics?
Yong CHEN ; Peipei LIU ; Feng GAO ; Hao CHENG ; Jianxun QI ; George F GAO
Protein & Cell 2010;1(2):153-160
PD-L1 is a member of the B7 protein family, most of whose members so far were identified as dimers in a solution and crystalline state, either complexed or uncomplexed with their ligand(s). The binding of PD-L1 with its receptor PD-1 (CD279) delivers an inhibitory signal regulating the T cell function. Simultaneously with the Garboczi group, we successfully solved another structure of human PD-L1 (hPD-L1). Our protein crystallized in the space group of C222(1) with two hPD-L1 molecules per asymmetric unit. After comparison of reported B7 structures, we have found some intrinsic factors involved in the interaction of these two molecules. Based on these results, we tend to believe this uncomplexed hPD-L1 structure demonstrated its potential dimeric state in solution, although it could just be an evolutionary relic, too weak to be detected under present technology, or still a functional unit deserved our attentions.
Antigens, CD
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chemistry
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immunology
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B7-H1 Antigen
;
Crystallography, X-Ray
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Evolution, Molecular
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Humans
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Protein Multimerization
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Protein Structure, Quaternary
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Protein Structure, Secondary
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T-Lymphocytes
;
chemistry
;
immunology
10.Antenatal Anxiety: Prevalence and Patterns in a Routine Obstetric Population.
Tze Ern CHUA ; Dianne Carrol BAUTISTA ; Kok Hian TAN ; George YEO ; Helen CHEN
Annals of the Academy of Medicine, Singapore 2018;47(10):405-412
INTRODUCTION:
Expectant mothers may appear anxious even during healthy pregnancies. Unfortunately, little is known about antenatal anxiety, and affected women may remain undetected and untreated. This study aimed to examine the prevalence, incidence, course and associations of high state anxiety in routine obstetric care.
MATERIALS AND METHODS:
This was an observational prospective cohort study at a large maternity unit. Obstetric outpatients with low-risk singleton pregnancies were recruited during first trimester consultations. Participants provided sociodemographic data and completed the State-Trait Anxiety Inventory (STAI) and Edinburgh Postnatal Depression Scale. The STAI was re-administered at each subsequent trimester.
RESULTS:
Prevalence and incidence of high state anxiety among 634 completers were 29.5% (95% CI 25.6%-33.6%) and 13.9% (95% CI 9.9%-18.0%), respectively. Anxiety was persistent in 17.0% (95% CI 14.3%-20.2%) and transient in 26.3% (95% CI 23.1%-29.9%). Only persistently anxious participants had high mean second trimester state anxiety scores. Odds for anxiety of greater persistence increased by 29% (95% CI 24%-35%) per 1-point increase in first trimester depression scores, and decreased by 36% (95% CI 7%-56%) with tertiary education.
CONCLUSION
Antenatal anxiety symptoms are common even in normal pregnancies, especially among women with depression and lower education. Our study indicates value in exploring diagnostic criteria and quantitative measures for antenatal anxiety.
Adult
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Anxiety Disorders
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diagnosis
;
epidemiology
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Cohort Studies
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Confidence Intervals
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Depressive Disorder
;
diagnosis
;
epidemiology
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Female
;
Humans
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Odds Ratio
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Pregnancy
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Pregnancy Complications
;
diagnosis
;
epidemiology
;
Pregnancy Outcome
;
Pregnancy Trimester, First
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Prenatal Diagnosis
;
Prevalence
;
Prospective Studies
;
Risk Assessment
;
Severity of Illness Index
;
Singapore