2.Induce and differentiation of pig Müller cells into photoreceptors in vitro
Ni, XU ; Yongqing, LIU ; Dean C DOUGLAS ; Fangtian, DONG
Chinese Journal of Experimental Ophthalmology 2016;34(1):43-48
Background Recent studies indicated that rat and mouse Müller cells can be induced and differentiated into photoreceptor-like cells in vitro, but it is not known whether this also happens to adult pig Müller cells nowadays.Objective This study was to test whether adult pig Müller cells can be differentiated to the retinal photoreceptors (the primary transmission neurons of the retina) in vitro.Methods Müller cells were isolated from the neural retina of adult pig eyes and cultured and passaged.The 3rd and 4th generation of cells were themonolayerly cultured,and the cells forced to form spheres in suspension in altra-low adherent dishes for 2-3 days first and then reseeded in normal adherent plates,and both of them were cultured in a specifically formulated medium to induce the differentiation of retinal photoreceptor.The cells was verified by immunocytochemistry.Cell morphology and immunofluorescence staining were utilized to measure the efficacy of the differentiation.Results The 2nd,3rd and 4th generation of Müller cells expressed glutamate synthetase (GS) , a specific maker of Müller cells.Inaddition, the 3rd generation of cells also expressed glial fibrillary acidic protein (GFAP) and another specific maker of Müller cells.Three visual fields under fluorescence-microscope were randomly chosen to calculate the average positive ratio of rhodopsin,a specific marker of mature photoreceptors.The photoreceptor differentiation ratios of the 2nd generation of cells for monolayer culture only and with additional sphere suspension culture were (27.99±6.53 (% and (16.54±3.40) % , respectively.With passages, the number of rhodopsin positive cells gradually decreased, and the intensity of rhodopsin expression gradually weakened.The directed rhodopsin positive ratios of the 2nd,3rd and 4th generation of cells from sphere formation were (56.23±7.32)% , (36.26 ±8.55)% and (12.68 ±3.18)% , respectively.Although the rhodopsin expression was weakened over passages,the differentiated cells were more slender and elongated.There was no statistic ally significant difference between different groups (F =2.618, P =0.099).Conclusions Adult pig Müller cells can be differentiated into retinal photoreceptors in vitro.The morphology of the differentiated cells appears moreslender and elongates if the sphere-induced differentiation method is used and/or the directed differentiation time is further extended.
3.Quantative measurement of tumor-associated antigen by autoradiography.
June Key CHUNG ; Dong Soo LEE ; Myung Chul LEE ; Chang Soon KOH ; James C REYNOLDS
Journal of the Korean Cancer Association 1991;23(4):740-748
No abstract available.
Autoradiography*
4.Analysis of remaining renal Function After nephrectomy in Mongrea Dogs.
Korean Journal of Urology 1971;12(3):253-268
No abstract available.
Animals
;
Dogs*
;
Nephrectomy*
5.Cognitive aspect of diagnostic errors.
Dong Haur PHUA ; Nigel C K TAN
Annals of the Academy of Medicine, Singapore 2013;42(1):33-41
Diagnostic errors can result in tangible harm to patients. Despite our advances in medicine, the mental processes required to make a diagnosis exhibits shortcomings, causing diagnostic errors. Cognitive factors are found to be an important cause of diagnostic errors. With new understanding from psychology and social sciences, clinical medicine is now beginning to appreciate that our clinical reasoning can take the form of analytical reasoning or heuristics. Different factors like cognitive biases and affective influences can also impel unwary clinicians to make diagnostic errors. Various strategies have been proposed to reduce the effect of cognitive biases and affective influences when clinicians make diagnoses; however evidence for the efficacy of these methods is still sparse. This paper aims to introduce the reader to the cognitive aspect of diagnostic errors, in the hope that clinicians can use this knowledge to improve diagnostic accuracy and patient outcomes.
Affect
;
Attitude of Health Personnel
;
Cognition
;
Diagnosis, Differential
;
Diagnostic Errors
;
psychology
;
Humans
;
Physicians
;
psychology
;
Prejudice
;
Thinking
6.Clusterin confers paclitaxel resistance in ovarian cancer.
Dong Choon PARK ; Seung Geun YEO ; Samuel C MOK
Korean Journal of Obstetrics and Gynecology 2005;48(10):2313-2320
OBJECTIVE: To evaluated whether clusterin over-expression is significantly correlated with paclitaxel resistance in ovarian cancer cell lines. METHODS: Clusterin was validated by performing expression profiling analysis and subsequently, the correlation between clusterin mRNA expression levels and the IC50 of paclitaxel was tested. Transfection of clusterin was performed on SKOV3, which expressed paclitaxel-sensitivity and low level of clusterin, and transfection of clusterin siRNA on PEOH, which expressed paclitaxel-resistance and high level of clusterin, to evaluate their effect on chemo-sensitivity, apoptosis, and cell cycle by XTT assay, cell death ELISA, and flow cytometry, respectively. RESULTS: Clusterin mRNA and protein expression levels were significantly correlated with paclitaxel resistance (P<0.001). Transfection of cluterin on SKOV3 significantly decreased apoptosis and increased paclitaxel resistance. And transfection of clusterin siRNA on PEOH significantly increased paclitaxel-sensitivity (P<0.05), and shifted cells from S to G2/M phase of the cell cycle after paclitaxel treatment. CONCLUSION: These findings suggested that clusterin overexpression confers paclitaxel-resistance by the modulation of the apoptotic pathway and cell cycle progression in ovarian cancer cells.
Apoptosis
;
Cell Cycle
;
Cell Death
;
Cell Line
;
Clusterin*
;
Enzyme-Linked Immunosorbent Assay
;
Flow Cytometry
;
Inhibitory Concentration 50
;
Ovarian Neoplasms*
;
Paclitaxel*
;
RNA, Messenger
;
RNA, Small Interfering
;
Transfection
7.Association Between SLC6A4 Serotonin Transporter Gene Linked Polymorphic Region and ADRA2A -1291C>G and Irritable Bowel Syndrome in Korea.
Yoon Jin CHOI ; Sung Wook HWANG ; Nayoung KIM ; Ji Hyun PARK ; Jane C OH ; Dong Ho LEE
Journal of Neurogastroenterology and Motility 2014;20(3):388-399
BACKGROUND/AIMS: Despite numerous studies on the relation of genetic polymorphisms with irritable bowel syndrome (IBS), the results still remain inconclusive. The aim of this study was to assess the possible association between SLC6A4 serotonin transporter gene linked polymorphic region (5-HTTLPR), ADRA2A -1291C>G, GNB3 825C>T, CCK1R intron 779T>C and TRPV1 945G>C polymorphisms and IBS based on Rome III criteria in Korea. METHODS: Study subjects were prospectively recruited from visitors to Seoul National University Bundang Hospital between July 2009 and January 2014. Ninety-nine IBS patients and 171 healthy controls were enrolled. Polymorphisms of above-mentioned 5 genes were genotyped. Serum serotonin from 101 participants was measured by ELISA and compared according to SLC6A4 5-HTTLPR polymorphisms and IBS subtypes. RESULTS: Regarding SLC6A4 5-HTTLPR polymorphism, L/L genotype was significantly associated with the total IBS, constipation predominant IBS (IBS-C) and mixture of diarrhea and constipation IBS (IBS-M) (adjusted OR: 4.35, 95% CI: 1.04-16.67; adjusted OR: 11.11, 95% CI: 1.69-50.00 and adjusted OR: 5.56, 95% CI: 1.05-33.33, respectively). Carrying ADRA2A -1291G allele was significantly associated with total IBS and diarrhea predominant IBS (adjusted OR: 3.37, 95% CI: 1.16-9.77 and adjusted OR: 5.64, 95% CI: 1.18-27.01, respectively). IBS-C patients showed reduced level of serum serotonin compared to controls and patients with diarrhea predominant IBS (50.2 ng/mL vs. 69.0 ng/mL and 92.9 ng/mL, P = 0.017 and P = 0.001, respectively). CONCLUSIONS: Genetic polymorphisms of SLC6A4 5-HTTLPR and ADRA2A -1291C>G could be one of the pathophysiological factors of IBS in Korea. Reduced serum serotonin shown in the IBS-C group suggested a role of serotonin in IBS, but large study is needed for confirming genotypic difference in serum serotonin level.
Alleles
;
Constipation
;
Diarrhea
;
Enzyme-Linked Immunosorbent Assay
;
Genotype
;
Humans
;
Introns
;
Irritable Bowel Syndrome*
;
Korea
;
Polymorphism, Genetic
;
Polymorphism, Single Nucleotide
;
Prospective Studies
;
Receptors, Adrenergic
;
Seoul
;
Serotonin
;
Serotonin Plasma Membrane Transport Proteins*
8.Incidence of ptosis following trabeculectomy: a comparative study.
Man Sung SONG ; Dong Ho SHIN ; Thomas C SPOOR
Korean Journal of Ophthalmology 1996;10(2):97-103
The occurrence of ptosis after trabeculectomy has been a common postoperative complication. Many factors have been implicated in the development of postoperative ptosis. The purpose of this study was to investigate the incidence of ptosis following trabeculectomy and whether or not it was influenced by combined cataract surgery, type of conjunctival flap, and previous intraocular surgery. We reviewed 386 eyes of 386 patients who underwent either trabeculectomy alone or trabeculectomy combined with cataract surgery, with greater than 6 month follow-up. Ptosis occurred in 10.7% (18 of 150 eyes) after trabeculectomy alone and in 12.7% (30 of 236 eyes) after trabeculectomy with combined cataract surgery (p = 0.96). The incidence of ptosis was 12.3% (10 of 81 eyes) after limbus-based conjunctival flap and 12.5% (38 of 305 eyes) after fornix-based conjunctival flap (p = 0.98). There was no significant difference in the incidence of ptosis between primary surgery eyes (12.5%, 34 of 273 eyes) and secondary surgery eyes (12.4%, 14 of 113 eyes) (p = 0.97). The incidence of ptosis after trabeculectomy was about 12% overall and not significantly influenced by combined cataract surgery, type of conjunctival flap or previous ocular surgery.
Adolescent
;
Adult
;
Aged
;
Aged, 80 and over
;
Blepharoptosis/*etiology
;
Cataract Extraction/adverse effects/methods
;
Female
;
Follow-Up Studies
;
Glaucoma/surgery
;
Humans
;
Incidence
;
Male
;
Middle Aged
;
Postoperative Complications
;
Retrospective Studies
;
Trabeculectomy/*adverse effects
10.Histoscope: A Web-Based Microscopy Tool for Oral Histology Education
Nazlee SHARMIN ; Ava K. CHOW ; Alice S. DONG ; Nadine C. MILOS
Healthcare Informatics Research 2021;27(2):146-152
Objectives:
Histology, the study of tissue structure under a microscope, is one of the most essential yet least engaging topics for health professional students. Understanding tissue microanatomy is crucial for students to be able to recognize cellular structures and follow disease pathogenesis. Traditional histology teaching labs rely on light microscopes and a limited array of slides, which inhibits simultaneous observation by multiple learners, and prevents in-class discussions. We have developed an interactive web-based microscopy tool called “Histoscope” for oral histology in this context.
Methods:
Good quality microscope slides were selected for digital scanning. The slides were scanned with multiple layers of z-stacking, a method of taking multiple images at different focal distances. The digital images were checked for quality and were archived on Histoscope. The slides were annotated, and self-assessment questions were prepared for the website. Interactive components were programmed on the website to mimic the experience of using a real light microscope.
Results:
This web-based tool allows users to interact with histology slides, replicating the experience of observing and manipulating a slide under a real microscope. Through this website, learners can access a broad array of digital oral histology slides and self-assessment questions.
Conclusions
Incorporation of Histoscope in a course can shift traditional teacher-centered histology learning to a collaborative and student-centered learning environment. This platform can also provide students the flexibility to study histology at their own pace.