1.Construction and heterologous expression of a truncated Haemagglutinin (HA) protein from the avian influenza virus H5N1 in Escherichia coli
Chee Wei, T. ; Nurul Wahida, A.G. ; Shaharum, S.
Tropical Biomedicine 2014;31(4):792-801
Malaysia first reported H5N1 poultry case in 2004 and subsequently outbreak in
poultry population in 2007. Here, a recombinant gene encoding of peptide epitopes, consisting
fragments of HA1, HA2 and a polybasic cleavage site of H5N1 strain Malaysia, was amplified
and cloned into pET-47b(+) bacterial expression vector. DNA sequencing and alignment
analysis confirmed that the gene had no alteration and in-frame to the vector. Then, Histagged
truncated HA protein was expressed in Escherichia coli BL21 (DE3) under 1 mM IPTG
induction. The protein expression was optimized under a time-course induction study and
further purified using Ni-NTA agarose under reducing condition. Migration size of protein was
detected at 15 kDa by Western blot using anti-His tag monoclonal antibody and demonstrated
no discrepancy compared to its calculated molecular weight.
2.Surgeon-Performed Ultrasound-Guided Fine-Needle Aspiration Cytology (SP-US-FNAC) Shortens Time for Diagnosis of Thyroid Nodules.
Wei Xiang GU ; Chuen Seng TAN ; Thomas W T HO
Annals of the Academy of Medicine, Singapore 2014;43(6):320-324
INTRODUCTIONUltrasound-guided fine-needle aspiration cytology (US-FNAC) of thyroid nodules is an important diagnostic procedure. In most hospitals, patients are referred to radiologists for US-FNAC, but this often results in a long waiting time before results are available. Surgeon-performed US-FNAC (SP-US-FNAC) during the initial patient consultation attempts to reduce the waiting time but it is not known whether this is as accurate as radiologist-performed US-FNAC (RP-US-FNAC). The aim of this study is to compare the clinical efficiency between SP-US-FNAC and RP-US-FNAC.
MATERIALS AND METHODSA retrospective study was performed on patients from the Department of General Surgery, Tan Tock Seng Hospital (TTSH) who underwent an US-FNAC from August 2011 to May 2012. All cases of SP-US-FNAC were performed by a single surgeon. This study compared the rates of positive diagnoses achieved by SP-US-FNAC and RPUS- FNAC as well as the time interval to reach a cytological diagnosis by each group.
RESULTSA total of 40 cases of SP-US-FNAC and 72 cases of RP-US-FNAC were included in the study. SP-US-FNAC resulted in 28 (70%) positive diagnoses and 12 (30%) nondiagnoses while RP-US-FNAC resulted in 47 (65.3%) positive diagnoses and 25 (34.7%) non-diagnoses. These results were comparable (P=0.678). The median time taken to reach a cytological diagnosis was 1 working day for SP-US-FNAC and 29.5 working days for RP-US-FNAC resulting in a shorter interval to reaching a cytological diagnosis for SP-US-FNAC (P<0.001).
CONCLUSIONIn the workup of thyroid nodules, SP-US-FNAC is as accurate as RP-US-FNAC but significantly reduces the time taken to reach a cytological diagnosis. This leads to greater clinical efficiency in the management of patients with thyroid nodules, which in turn leads to other benefits such as decreased patient anxiety and increased patient satisfaction.
Adult ; Biopsy, Fine-Needle ; methods ; Female ; Humans ; Image-Guided Biopsy ; Male ; Middle Aged ; Retrospective Studies ; Specialties, Surgical ; Thyroid Nodule ; pathology ; Time Factors
3.Over-the-Scope Clip in the Treatment of Gastrointestinal Leaks and Perforations
Mike T. WEI ; Ji Yong AHN ; Shai FRIEDLAND
Clinical Endoscopy 2021;54(6):798-804
While perforations, postoperative fistulas, and leaks have traditionally led to surgical or interventional radiology consultation for management, the introduction of the over-the-scope clip has allowed increased therapeutic possibilities for endoscopists. While primarily limited to case reports and series, the over-the-scope clip successfully manages gastrointestinal bleeding, perforations, as well as postoperative leaks and fistulas. Retrospective studies have demonstrated a relatively high success rate and a low complication rate. Given the similarity to variceal banding equipment, the learning curve with the over-the-scope clip is rapid. However, given the higher risk of procedures involving the use of the over-the-scope clip, it is essential to obtain the scope in a stable position and grasp sufficient tissue with the cap using a grasping tool and/or suction. From our experience, while closure may be successful in lesions sized up to 3 cm, successful outcomes are obtained for lesions sized <1 cm. Ultimately, given the limited available data, prospective randomized trials are needed to better evaluate the utility of the over-the-scope clip in various clinical scenarios, including fistula and perforation management.
4.Genotyping and preparation of the recombinant nucleocapsid protein antigen of hantavirus
JQ TANG ; M CAO ; T TANG ; CJ WANG ; CB WEI ; WL LEI
Chinese Medical Journal 2001;114(10):1030-1034
Objective To identify new recombinant antigens with potential for diagnosis of hemorrhagic fever with renal syndrom (HFRS) and establish reverse transcription-polymerase chain reaction-restriction fragments length polymorphism (RT-PCR-RFLP) for genotyping of hantavirus. Methods One group of primers was used to clone the full-length S genome segment and the partial S genorme segment of the N-terminal. The two cloned genes were both fusionally expressed and non fusionally expressed in the T7 system. The other group of primers was used to establish a RT-PCR method to detect RNAs in 37 virus isolates, 2 positive standard virus strains of hantavirus and 5 negative controls. The method for typing RFLP was set up by digesting the PCR products of 20 virus isolates with Ras Ⅰ and Hind Ⅲ. Results The non-fusionally expressed products with a working concentration of 1:10 000 by chapping enzyme-linked immunosorbent assay (cELISA), presented good biological activity though yields were lower than that of the fusionally expressed products.The specific component of the hantavirus genome (299 bp or 577 bp) wes seen in all viral samples. The genotyping of hantavirus showed that 9 out of the total were hantann (HTN) viruses, 8 were seol (SEO) viruses and 3 were not determined. Conclusions The good working titrer of expressed recombinant antigen showed that it has the potential to replace the natural antigen for detecting hantavirus antibodies. On comparison with cELISA, the detection rates for these two methods were 100% and 84.6%, and the coincidence rate was 84.6%. The former had a 15.4% higher sensitivity than the latter. The typing efficiency of RT-PCR-RFLP and sero-typing method was 85% (17/20) and 55% (11/20), respectively, showing that the former was 30% higher than the latter, while their results were highly consistant.
5.Differences in Variation of Human Immunodeficiency Virus Type 1 Sequences from Henan and Shanghai Regions of China
Chun-yu, YIN ; Hong-zhou, LU ; Wei-ming, JIANG ; Maria Pia De PASQUALE ; Yue-kai, HU ; Xiao-zhang, PAN ; Xin-hua, WENG ; Richard T. D'AQUILA ; Yi-Wei, TANG
Virologica Sinica 2007;22(3):212-217
Illegally paid blood donation was a risk factor for HIV acquisition exclusively in Henan and Hubei Provinces of China, and not in Shanghai. Nucleotide sequences in the gag and env genes of HIV-1 were compared between isolates from Henan and Shanghai regions of China to test whether an expected higher degree of a common source of infections from this unique blood donation transmission risk would be evident as decreased variation among Henan isolates in an exploratory cross-sectional analysis. Among 38 isolates studied, 23 of 23 (100%) from Henan and 8 of 15 (54%) from Shanghai were subtype B. In addition, fewer sequence differences were found in gp41 of subtype B isolates from Henan than from Shanghai isolates. Further studies with additional controls are therefore warranted to confirm the role of the degree of a common source of infections in differences in HIV variation across populations.
6.Study on chemical constituents from leaves of Naudea officinalis.
Dawen XIE ; Yonghui LI ; Li ZHAO ; Gang DING ; Shaowei YUAN ; Jia XU ; Huarong ZHU ; Wei XIAO
China Journal of Chinese Materia Medica 2011;36(8):1037-1039
OBJECTIVETo study the chemical constituents of the leaves of Naudea officinalis.
METHODThe chemical constituents were separated by column chromatography and semi-preparative HPLC techniques, and their structures were determined by spectral analysis.
RESULTFive compounds were isolated and identified as strictosamide (1), 10-hydroxy strictosamide (2), kaempferol-3-O-rutinoside (3), rutin (4), pumiloside(5).
CONCLUSIONAmong these compounds, 2, 3, 4 are isolated from the leaves of Naudea officinalis for the first time.
Camptothecin ; analogs & derivatives ; chemistry ; isolation & purification ; Chromatography, High Pressure Liquid ; methods ; Kaempferols ; chemistry ; isolation & purification ; Magnetic Resonance Spectroscopy ; methods ; Plant Extracts ; chemistry ; isolation & purification ; Plant Leaves ; chemistry ; Rutin ; chemistry ; isolation & purification ; Vinca Alkaloids ; chemistry ; isolation & purification
7.Study on purification of strictosamide from Nauclea officinalis by macroporous resin.
Zhaoqing MENG ; Gang DING ; Yujie LIU ; Jia XU ; Wenjun LIU ; Wei XIAO
China Journal of Chinese Materia Medica 2011;36(8):1007-1010
OBJECTIVETo study on the purification of strictosamide from Nauclea officinalis by macroporous resin to provide reference for production.
METHODThe best macroporous resin was selected among 10 kinds of resins according to adsorption and desorption of the static adsorption experiments. The adsorption quantity, elution volume of water, concentration and elution volume of alcohol were determined according to the single factor experiment.
RESULTHPD400 was the best resin, and the best adsorption quantity was 20.23 mg x g(-1), the elution volume of water and 30% alcohol was 6 BV, and the elution volume of 70% alcohol was 4 BV.
CONCLUSIONThis technology is simple, feasible, and it can provide reference for the industrialized production.
Adsorption ; Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Ethanol ; chemistry ; Resins, Synthetic ; chemistry ; Rubiaceae ; chemistry ; Technology, Pharmaceutical ; methods ; Vinca Alkaloids ; chemistry ; isolation & purification
8.Changing epidemiological patterns of hepatitis A infection in Singapore.
Hsien Chieh LEE ; Li Wei ANG ; Paul K T CHIEW ; Lyn JAMES ; Kee Tai GOH
Annals of the Academy of Medicine, Singapore 2011;40(10):439-447
INTRODUCTIONSingapore has experienced remarkable socioeconomic progress over the last few decades, with a corresponding rise in standards of sanitation and living conditions. We undertook a study to describe its epidemiological trends of hepatitis A over the last 2 decades.
MATERIALS AND METHODSWe analysed the epidemiological data on all laboratory-confirmed cases of hepatitis A from 1990 to 2009. We also described 3 outbreaks which occurred in 1991, 1992 and 2002. To determine the changing prevalence of hepatitis A virus (HAV) infection, we compared the findings from a seroepidemiological study conducted in 1993 with earlier surveys in 1975 and 1984/1985.
RESULTSThe incidence of indigenous hepatitis A cases per 100,000 population declined significantly from 1.8 in 1989 to 0.7 in 2009, and more than half were imported. While majority of the imported cases were Singapore residents, the proportion of imported cases among Singapore residents had decreased significantly. Most of the Singapore residents contracted the disease from Southeast Asia and the Indian subcontinent. The overall prevalence of HAV infection in the population declined from 31.8% in 1984/85 to 25.9% in 1993.
CONCLUSIONThe incidence and seroprevalence of hepatitis A in Singapore are comparable to other developed countries. As Singapore is situated in a region highly endemic for HAV, it is very vulnerable to the introduction of the disease because of the high volume of regional travel and import of food, especially shellfish. While we note that there have been no further shellfish-associated outbreaks since 2002, sustained vigilance, strict control of food import by the authorities and public health education on the risk of consuming shellfish, especially cockles, raw and half-cooked, should be maintained.
Adolescent ; Adult ; Child ; Child, Preschool ; Disease Outbreaks ; Female ; Hepatitis A ; epidemiology ; etiology ; Hepatitis A Virus, Human ; isolation & purification ; Humans ; Immunoglobulin G ; immunology ; Infant ; Male ; Middle Aged ; Seroepidemiologic Studies ; Shellfish ; virology ; Singapore ; epidemiology ; Young Adult
9.Managing breast cancer diagnosed in first trimester pregnancy: a case report.
Ramesh WIJAYA ; Wei Sean YONG ; Allen W Y YEO ; Diana T H SEE
Annals of the Academy of Medicine, Singapore 2007;36(12):1024-1027
INTRODUCTIONBreast cancer is the most common malignancy in pregnant women, occurring at a rate of about 1 in 3000 pregnancies. Unfortunately, this will sometimes occur during the first trimester of pregnancy and this situation warrants discussion of management options with regard to the mother and child, especially with the current trend of deferring child bearing to a later age.
CLINICAL PICTUREWe present a 34-year-old primigravida who had a breast lump prior to confirmation of her pregnancy and received her diagnosis of invasive breast cancer at 7 weeks' amenorrhoea. The oncologic management options of this pregnant patient with breast cancer are discussed.
TREATMENTThe patient eventually opted to undergo wide excision of the breast cancer with sentinel lymph node biopsy and possible axillary clearance together with termination of her pregnancy.
RESULTSThe patient successfully underwent surgery for her breast cancer and was subsequently treated with adjuvant therapy as per normal protocol for a non-pregnant patient.
CONCLUSIONThe management of breast cancer and pregnancy occurring concurrently is a complex problem fraught with many dilemmas for both the medical team, the patient and her family. The option chosen must involve a multidisciplinary team and have full informed consent of the patient.
Abortion, Induced ; Adult ; Breast Neoplasms ; diagnosis ; drug therapy ; surgery ; Female ; Humans ; Pregnancy ; Pregnancy Trimester, First ; Sentinel Lymph Node Biopsy
10.The related factors influencing development of language understanding and expression of early-children.
Bo HAO ; Wei-lan LIANG ; Shuang WANG ; Zhi-xiang ZHANG ; Qi-hua ZUO ; Tardif T ; Fletcher P
Chinese Journal of Preventive Medicine 2005;39(6):403-405
OBJECTIVETo assess the level of language understanding and expression of healthy children aged from 8 to 16 months in urban Beijing and to investigate the children's physical and psychological development conditions and social and economic status of children's family as to identifying the related factors to children's language development and providing a basis for instructing parents child-rearing and promoting early children language development.
METHODSA quantitative Cross-sectional Study was made. The parents or care givers of 636 healthy young children, randomly stratified and selected in two districts in Beijing were interviewed. T-test was used to compare the scores of language understanding and expression between boys and girls in the same age. Single and multiple factors analysis were used so as to find out the related factors.
RESULTSFor boys, the average scores of language were respectively 115.0 for 8 months, 243.0 for 12 months and 410.6 for 16 months; for girls the average scores were respectively 109.9 for 8 months, 286.4 for 12 months and 456.2 for 16 months. The average score of language understanding of boys was higher than that of girls only in the 11 month group. The average scores of language expression of girls were higher than those of boys in 11, 12, 14, 15 month groups. Multiple factors analysis showed that parent-child book reading, parent-child tape listening, higher education level of grandmothers, children' extroversion personality, child being able to speak one word and children's age were positively related to the children' language score.
CONCLUSIONProviding rich language environment should be helpful to early children's language development.
China ; Cross-Sectional Studies ; Female ; Humans ; Infant ; Language Development ; Male ; Reading ; Speech ; Surveys and Questionnaires ; Urban Population ; statistics & numerical data