This study examined the current changes of human ether-a-go-go-related gene (hERG) mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identified and site-directed mutagenesis was performed to induce the mutation in wild-type (WT) hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A>G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of -40 mV after depolarizing at +50 mV, tail current densities were 83.35±7.06 pA/pF in WT and 50.38±7.74 pA/pF in V535M respectively (n=20, P<0.01). Gating kinetics of hERG revealed that V (1/2) of steady-state inactivation shifted to negative potential in the mutant (V (1/2,V535M): -61.81±1.7 mV vs. V (1/2, WT): -43.1±0.71 mV). The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.

OBJECTIVE:To optimize the extraction technology for flavonoids in leaves and seeds of Hippophae rhamnoides. METHODS:Using the total extraction rate of 6 flavonoid aglycones(catechins,rutin,myricetin,quercetin,kaempferol,isorham-netin)as index,ethanol volume fraction,extraction time,extraction times,material-lipid ratio as investigation indexes,L9(34)or-thogonal test was designed to optimize the extraction technology of flavonoids in leaves and seeds of H. rhamnoides,and verifica-tion test was carried out. RESULTS:The optimum extraction technology for flavonoids in leaves of H. rhamnoides was ethanol vol-ume fraction of 70%,extracting for 3 times with material-lipid ratio of 1:16,and 2.0 h each time;and that of seeds was ethanol volume fraction of 50%,extracting for 3 times with material-lipid ratio of 1:24,and 1.5 h each time. In verification test,the total extraction rate of 6 flavonoid aglycones was 56.4 mg/g in the leaves (RSD=1.4%,n=3) and 15.4 mg/g in the seeds (RSD=3.4%,n=3). CONCLUSIONS:Optimized extraction technology is simple,stable,feasible,and can be used for extracting the fla-vonoids in leaves and seeds of H. rhamnoides.

Objective To determine whether sleep-disordered breathing (SDB) may lead to nocturnal myocardial ischemia and whether the severity of this ischemia may be relieved by nasal continuous positive airway pressure (CPAP). Methods Overnight polysomnogram examination and simultaneous 3-channel Holter monitoring were performed on 76 patients with moderate to severe SDB and no history of coronary heart disease. All the cases were treated with CPAP for one night. ST depression was defined as a ST segment decrease of more than 1 mm from baseline and lasting 1 min or more. The total duration (minutes) of ST depression was indexed to the total sleep time (minutes per hour of sleep). Results Twenty-eight patients (37%) showed ST segment depression during their sleep. Before CPAP treatment, the respiratory disturbance index (RDI) and arousal index were significantly higher during periods of ST depression than when ST segments were isoelectric, whereas no significant difference was found in blood oxygen saturation (SaO2). After the CPAP treatment of patients with ST depression, the duration of ST depression was significantly reduced from 36.8±18.9 to 11.4±13.2 min/h (P＜0.05). ST depression-related indexes, including RDI, arousal index and the percentage of sleep time spent at SaO2 below 90% (TS90/ TST), were all significantly decreased, with RDI from 63.4±23.8 to 8.1±6.6 /h, arousal index from 51.2±18.9 to 9.6±5.4 /h, and TS90/ TST from 50.6±21.4 to 12.9±14.7% (P＜0.05). Conclusion ST-segment depression is rather common in patients with moderate to severe SDB, and CPAP treatment can significantly reduce the duration of ST depression. ST depression in these patients may reflect the myocardial ischemia that really exists and the non-ischemic changes associated with recurrent SDB.

This study examined the current changes of human ether-a-go-go-related gene (hERG) mutation derived from a LQT2 Chinese family with a highly penetrating phenotype.Mutation was identified and site-directed mutagenesis was performed to induce the mutation in wild-type (WT) hERG.WT　hERG and mutated V535M were cloned and transiently expressed in HEK293 cells.At the 48th and 72nd h after transfection,membrane currents were recorded using whole cell patch-clamp procedures.An A＞G transition at 1605 resulting in replacement of V535M was identified.Compared to WT,V535M mutation significantly decreased tail currents of hERG.At test potential of-40 mV after depolarizing at +50 mV,tail current densities were 83.35±7.06 pA/pF in WT and 50.38±7.74 pA/pF in V535M respectively (n=20,P＜0.01).Gating kinetics of hERG revealed that V1/2 of steady-state inactivation shifted to negative potential in the mutant (V1/2,V535M:-61.81±1.7 mV vs.V1/2,WT:-43.1±0.71mV).The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials.V535M hERG mutation demonstrated markedly decreased tail current densities,which suggests that V535M is a new loss-of-function mutation of bERG channel responsible for LQT2.

Objective:To investigate whether endoplasmic reticulum transmembrane protein IRE1(encoded by Ern1)can modulate the immunogenicity and tumorigenicity of cancer cells and explore the underlying mechanism.Methods:Correlation between ERN1 expression and the overall survival of cancer patients was explored with public cancer databases.CRISPR-Cas9 technology was used to delete Ern1 in mouse tumor cell lines MCA205 and TC-1.By CCK-8,flow cytometry,ELISA,luciferase reporter systems,subcutaneous tumor models,prime-boost regimens,we analyzed impact of Ern1 on tumor cell proliferation in vitro and tumor growth in vivo,intratumoral immune cell composition,tunicamycin-induced immunogenic cell death and activation of anti-tumor effector T cells.The growth kinetics of Ern1-/-tumors was also monitored in Ifnar-/-mice.Results:ERN1 expression was found to be negatively correlated with the overall survival of cancer patients across multiple cancer types.Although Ern1 deficiency didn't affect tumor cell proliferation in vitro,it largely delayed tumor growth or caused spontaneous tumor regression in immune-competent mice.As compared to wild type counterparts,Ern1-/-tumors harbored much more neutrophils but significantly less CD4+T cells.Upon tunicamycin-induced endoplasmic reticulum stress,Ern1-/-cells were more vulnerable to cell death.Although Ern1-deficiency reduced HMGB1 release and calreticulin exposure,IFN-α/β secretion was increased,and strongly elevated type Ⅰ IFN response in tumor cells and augmented IFN-γ production by anti-tumor effector T cells.Ern1-/-tumor cells restored the tumorigenic capacity in Ifnar-/-mice.Conclusion:Ern1 defi-ciency can enhance the immunogenicity of tumor cells and inhibit tumor outgrowth by boosting endoplasmic reticulum stress-induced type Ⅰ IFN response.

Objective To investigate the effect of miR-217 on gefitinib resistance in non-small cell lung cancer(NSCLC),and to explore the downstream target genes and related pathways.Methods qRT-PCR was used to detect the expression of miR-217 in human lung normal epithelial cell lines BEAS-2B,NSCLC cell lines A549,HCC827,PC9,NCI-H1975 and gefitinib resistant strain PC9/GR.PC9/GR cells were selected and the cells of control group,NC-mimic group,miR-217 mimic group,miR-217 mimic+si-NC group,and miR-217 mimic+si-FOXO3 group were constructed using liposome transfection technique.CCK8 and clonal formation assay were used to detect changes in cell proliferation capacity,flow cytometry was used to detect changes in cell apoptosis capacity,and western blot was used to detect protein expression related to PI3K/AKT signaling pathway.The Targetscan bioinformatics website predicted the downstream target genes of miR-217,and the correlation between miR-217 and the target gene FOXO3 was detected by dual luciferase assay.Results Compared with BEAS-2B cells,the expression of miR-217 in A549,HCC827,PC9 and NCI-H1975 cells was significantly decreased(P＜0.05).With the increase of gefitinib concentration,the expression of miR-217 gene in PC9 cells was gradually decreased(P＜0.05),and the expression of miR-217 in PC9/GR cells was lower than that in PC9(P＜0.05).Compared with the control group and NC-mimic group,the cell proliferation capacity of miR-217 mimic group was significantly decreased(P＜0.05),the number of apoptosis was increased(P＜0.05),and the expression levels of p-PI3K and p-AKT were decreased(P＜0.05).Dual luciferase reporter gene assay proved that FOXO3 is the target of miR-217.Compared with miR-217 mimic group and miR-217 mimic+si-NC group,the cell drug resistance of miR-217 mimic+si-FOXO3 group was increased(P＜0.05),the proliferation ability was significantly increased(P＜0.05),and the number of apoptosis was decreased(P＜0.05).The expression levels of P-PI3K and P-AKT were increased(P＜0.05).Conclusion Overexpression of miR-217 reversed the resistance of PC9/GR to gefitinib in NSCLC cells and inhibited the proliferation and accelerated apoptosis of PC9/GR cells,which may be related to the regulation of PI3K/AKT signaling pathway by targeting FOXO3.

INTRODUCTIONIncreasing financial challenges have resulted in great debt among medical graduates worldwide. In Singapore, more scholarships and bursaries have been disbursed in recent years to support students who are financially challenged. We aimed to study the financial status of medical students in National University of Singapore (NUS) Yong Loo Lin School of Medicine (i.e. NUS Medicine), Singapore, and the financial support available to them.

METHODSA cross-sectional quantitative study was performed. Surveys were distributed and completed by medical students of NUS Medicine. Information regarding household income, financial assistance, monthly allowance and expense, and concurrent occupations was collected. We compared our findings with the results of a similar study performed in 2007 and national income data.

RESULTSA total of 956 (66.2%) out of 1,445 medical students completed the survey. 19.5% and 58.5% of respondents came from households with monthly incomes < SGD 3,000 and > SGD 7,000, respectively. 20.6% of students had loans, 18.9% had scholarships and bursaries, and 14.4% worked to support themselves.

CONCLUSIONMedical school fees have risen by more than 50% over the past ten years. Our study found that there were increases in the proportion of students from both the lower- and higher-income segments, with proportionally fewer students from the middle-income segment. A large number of students were working and/or had some form of financial support. More should be done to meet the needs of financially challenged medical students to ensure equal access to quality medical education.

INTRODUCTIONPerioperative glycaemic control is an important aspect of clinical management in diabetic patients undergoing cataract surgery under local anaesthesia. While poor long-term glycaemic control has significant implications for surgery, perioperative hypoglycaemia or hyperglycaemia may also compromise patient safety and surgical outcomes. We aimed to survey ophthalmologists and anaesthesiologists on their approach and to identify the prevalent practice patterns in Singapore.

METHODSThis was a cross-sectional questionnaire-based survey conducted in four public hospitals in Singapore with established ophthalmology and anaesthesia units. Respondents were approached individually, and the self-administered questionnaires comprised questions related to practice patterns, clinical scenarios and awareness of pre-existing guidelines.

RESULTSA total of 129 doctors responded to the questionnaire survey. 76 (58.9%) were from ophthalmology departments and 53 (41.1%) were from anaesthesia departments. The majority chose to withhold oral hypoglycaemic agents (82.9%) and/or insulin (69.8%), and keep the patient fasted preoperatively. A blood glucose level ≥ 17 mmol/L prompted 86.0%-93.8% of respondents to adopt a treat-and-defer strategy, while a level ≥ 23 mmol/L prompted 86.0%-96.9% of respondents to cancel the cataract surgery. The respondents were consistently more concerned about perioperative hyperglycaemia (n = 99, 76.7%) than intraoperative hypoglycaemia (n = 83, 64.3%).

CONCLUSIONThe current study presented the prevalent practice patterns of ophthalmologists and anaesthesiologists in the perioperative management of diabetic patients undergoing cataract surgery in four public hospitals in Singapore. Further research in this field is required, and may be useful for the future formulation of formal guidelines and protocols.

Adult ; Anesthesia, Local ; methods ; Anesthesiologists ; statistics & numerical data ; Blood Glucose ; analysis ; Cataract Extraction ; Cross-Sectional Studies ; Diabetes Mellitus ; blood ; epidemiology ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Ophthalmologists ; statistics & numerical data ; Perioperative Care ; methods ; Singapore ; epidemiology ; Surveys and Questionnaires

INTRODUCTION: Medical school fees are rising globally. Student debt and financial background may affect residency choices, but few studies have been conducted in Asia. This study aimed to explore the relationship between financial background, student debt and postgraduate residency choices among medical students in Singapore. METHODS: An anonymised survey of all medical students in Singapore was conducted and had a response rate of 67.9%. RESULTS: 40.5% of our study population would graduate with debt. Medical students with monthly per capita household income < SGD 1,000 were more likely to graduate with debt (unadjusted odds ratio [OR] 2.0, 95% confidence interval [CI] 1.6-2.7; p < 0.001) and feel burdened by the cost of medical education (unadjusted OR 2.8, 95% CI 2.0-3.9; p < 0.001). Students with monthly per capita household income < SGD 1,000 (unadjusted OR 1.818, 95% CI 1.338-2.470, p < 0.001; adjusted OR 1.692, 95% CI 1.202-2.381, p = 0.003) and those with debt (unadjusted OR 1.623, 95% CI 1.261-2.090, p < 0.001; adjusted OR 1.393, 95% CI 1.048-1.851, p = 0.022) were more likely to rank at least one economic factor as 'very significant' in influencing their postgraduate training choices. CONCLUSION It is concerning that despite financial aid schemes, the cost of medical education remains a burden to students from lower-income households in Singapore. Student debt and financial background may distort postgraduate career choices, creating an undue push towards high-paying specialties.
Career Choice ; Choice Behavior ; Education, Medical ; economics ; Humans ; Internship and Residency ; economics ; Odds Ratio ; Schools, Medical ; economics ; Singapore ; Social Class ; Students, Medical ; statistics & numerical data ; Surveys and Questionnaires ; Training Support