1.Activation of Neutrophil Menbrane Phospholipase D by Soluble Proteins: Comparison of Cytosolic Neutrophil 50 kDa Factor , ADP-ribosylation Factor and a Novel Brain Factor.
Yong KIM ; Jong Young KWAK ; Tae Hoon G LEE ; Isabel LOPEZ ; J David LAMETH ; Pann Ghill SHU ; Sung Ho RYU
Korean Journal of Immunology 1999;21(3):183-191
GTPrS-dependent phospholipase D activity in human neutrophils was investigated using exogenous phospholipid as a substrate. Both cytosolic and membrane- associated phospholipase D activities were identified. The previously described 50 kDa cytosolic activating factor was resolved chromatographically from the cytosolic phospholipase D. Using exogenous phospholipid as substrate along with chromatographically resolved 50 kDa factor and recombinant ADP-ribosylation factor 1, plasma membrane was required for activity, indicating that the activity which was previously seen using endogenous phospholipid substrate was due to a phospholipase D located in the plasma membrane. In addition, ADP-ribosylation factor and the 50 kDa factor activated synergistically. Using neutrophil plasma membranes, a third regulator of neutrophil membrane phospholipase D was identified from bovine brain cytosol. This factor was resolved from ADP-ribosylation factor and Rho A by successive column chromatographies. The brain factor showed a synergistic effect with the 50 kDa neutrophil activator but an additive effect with recombinant ADP- ribosylation factor. Whether or not ADP-ribosylation factor or the brain factor were present, high activities were seen only when the 50 kDa factor was present, indicating that the 50 kDa cytosolic factor is a major activating factor for the neutrophil plasma membrane phospholipase D.
ADP-Ribosylation Factor 1
;
ADP-Ribosylation Factors*
;
Brain*
;
Cell Membrane
;
Chromatography
;
Cytosol*
;
Fibrinogen
;
Humans
;
Membranes
;
Neutrophils*
;
Phospholipase D*
;
Phospholipases*
2.NADPH oxidase mediated oxidative stress in hepatic fibrogenesis.
Yong Han PAIK ; David A BRENNER
The Korean Journal of Hepatology 2011;17(4):251-257
NADPH oxidase (NOX) is a multicomponent enzyme complex that generates reactive oxygen species (ROS) in response to a wide range of stimuli. ROS is involved as key secondary messengers in numerous signaling pathways, and NADPH oxidases complex has been increasingly recognized as key elements of intracellular signaling of hepatic fibrogenesis. In the liver, NADPH oxidase is functionally expressed both in the phagocytic form and in the non-phagocytic form. The non-phagocytic NADPH oxidase complex is structurally and functionally similar to the phagocytic NADPH, resulting in reduction of molecular oxygen to generate superoxide. There are six homologous NOX proteins in the non-phagocytic forms of NADPH oxidase. An emerging concept is that both phagocytic and nonphagocytic NADPH oxidase components in hepatic stellate cells (HSCs) mediate hepatic fibrosis, suggesting its potential role as a pharmacological target for anti-fibrotic therapy. The molecular components and signaling pathways of various NADPH oxidase homologues that are critical for the fibrotic activity in HSCs need to be more clearly identified.
Angiotensin II/metabolism
;
Hepatic Stellate Cells/metabolism
;
Humans
;
Liver Cirrhosis/*enzymology/pathology
;
NADPH Oxidase/*metabolism
;
Oxidative Stress
;
Reactive Oxygen Species/metabolism
3.Frontalis Transfer and Closed Silicone Rod Frontalis Suspension.
Yong Jig LEE ; David Dae Hwan PARK
Archives of Aesthetic Plastic Surgery 2016;22(1):3-9
BACKGROUND: Improvements in the degree of marginal reflex distance 1 (MRD1) were compared before and after use of the frontalis transfer (FT) method and closed silicone rod frontalis suspension surgery (SS) for severe blepharoptosis under general or local anesthesia with or without minimal sedation. METHODS: We reviewed the medical records and photographs of 76 patients who had visited our institute between 2006 and 2013 because of severe blepharoptosis with poor levator function and treated by the same senior doctor. RESULTS: In total, 104 eyes (63 patients) were included after applying exclusion criteria; 71 eyes (44 patients) were corrected using FT, and 33 eyes (19 patients) were corrected using the frontalis sling method with a silicone rod. Among the general FT, local FT, general SS, and local SS groups, the mean preoperative MRD1 was not significantly different. Postoperative MRD1 was highest in the local FT group. CONCLUSIONS: Both FT and SS positively increased MRD1, regardless of the anesthesia used; however, the change in MRD1 of the general SS group was the lowest (1.11+/-0.848 mm). Further, general FT, local FT, and local SS groups had an approximate 2 mm or greater increase in the differences between postoperative and preoperative MRD1. Specifically, the local FT group had a definite positive correlation with postoperative MRD1.
Anesthesia
;
Anesthesia, Local
;
Blepharoptosis
;
Eyelids
;
Humans
;
Medical Records
;
Reflex
;
Silicon*
;
Silicones*
4.Teleophthalmology and its evolving role in a COVID-19 pandemic: A scoping review.
Jiamin Charmaine CHONG ; Chai-Hoon Nowel TAN ; David Z CHEN
Annals of the Academy of Medicine, Singapore 2021;50(1):61-76
INTRODUCTION:
Teleophthalmology may assist the healthcare sector in adapting to limitations imposed on clinical practice by a viral pandemic. A scoping review is performed in this study to assess the current applications of teleophthalmology for its suitability to diagnose, monitor or manage ophthalmological conditions with accuracy.
METHODS:
A search of PubMed was conducted for teleophthalmology-related articles published from 1 January 2018 to 4 May 2020. Only articles that focused on the use of teleophthalmology in terms of diagnosis and management, as well as its benefits and detriments, were included. The Mixed Methods Appraisal Tool (MMAT) was used to assess the quality of the included articles.
RESULTS:
A total of 38 articles were assessed at the full-text level. There were 2 qualitative studies and 1 quantitative randomised controlled trial, while the majority were either quantitative descriptive studies (19, 50.0%) or quantitative non-randomised studies (16, 42.1%). Overall, 8 studies described reducing manpower requirements, 4 described reducing direct patient-doctor contact, 17 described storage of medical imaging and clinical data, and 9 described real-time teleconferencing. The MMAT analysis revealed limitations in appropriate sampling strategy in both quantitative non-randomised studies (9 of 16, 56.3%) and quantitative descriptive studies (9 of 19, 47.4%). Cost-effectiveness of teleophthalmology was not performed in any included study.
CONCLUSION
This current review of the various aspects of teleophthalmology describes how it may potentially assist the healthcare sector to cope with the limitations imposed by a viral pandemic through technology. Further research is required to evaluate the cost-effectiveness of the various strategies.
COVID-19/transmission*
;
Humans
;
Ophthalmology/organization & administration*
;
Telemedicine/organization & administration*
5.Rehabilitation of mandibular edentulous patients with a few unilateral remaining teeth using implant-assisted removable partial denture: A case report.
Bhumgey David LEE ; Yong Sang LEE
The Journal of Korean Academy of Prosthodontics 2019;57(1):42-48
In the case of a patient with a small number of unilateral remaining teeth in the mandible, a restoration with conventional removable partial denture cannot provide sufficient retention and resistance. A harmful stress from the poor stability of denture on remaining teeth occurs due to alveolar bone resorption in edentulous area. Although implant fixed prosthesis can provide multiple benefits over conventional removable partial denture, there are limitations come from anatomic structures and costs. In this case, an implant-assisted removable partial denture (IARPD) with a couple of implants placed in strategic positions can be a treatment modality. The objective of this article is to present a case report of two patients showed satisfactory clinical outcomes during three-year follow-up period describing the fabrication and advantages of removable partial denture assisted by teeth and implants (IARPD) for a patient with a small number of unilateral remaining teeth in mandible using Locator as an implant attachment.
Bone Resorption
;
Denture, Partial, Removable*
;
Dentures
;
Follow-Up Studies
;
Humans
;
Mandible
;
Prostheses and Implants
;
Rehabilitation*
;
Tooth*
6.Five-year Change in Corneal Endothelial Cell Density after Foldable Iris-fixed Lens Insertion
Myungsik NAM ; David Sung Yong KANG ; Sun Woong KIM
Journal of the Korean Ophthalmological Society 2021;62(4):479-486
Purpose:
To investigate changes in corneal endothelial cell density over 5 years after implantation of Artiflex lenses (Ophtec BV, Groningen, The Netherlands) and to explore the influence of anterior chamber depth and volume on changes in endothelial cell density.
Methods:
This study included 146 eyes of 88 patients implanted with foldable phakic iris-fixation intraocular (Artiflex) lenses for myopia correction from March 2009 to March 2014. To simulate chronological changes in endothelial cell density with age, we collected normal endothelial cell density data from 100 healthy subjects aged 20, 25, or 30 years, and compared the changes among these groups at 5 years after surgery. Changes in corneal endothelial cell density were compared among four groups to which subjects were assigned based on the distance from the intraocular lens to the corneal endothelium, and the volume and depth of the preoperative anterior chamber.
Results:
The mean endothelial cell density, pre-operatively and at 1, 3, and 5 years post-operatively, was 3,038.8 ± 223.2, 2,985.3 ± 235.5, 2,905.1 ± 231.3, and 2,814.9 ± 250.5 cells/mm2, respectively (1.73%, 4.36%, and 7.31% reduction, respectively, vs. pre-operatively, p < 0.001). These differences were greater than those observed among different age groups (2.2% difference between 20- and 25-year-olds, and 1.2% difference between 25- and 30-year-olds, p < 0.001). A shorter distance from the lens to the endothelium and smaller anterior chamber volume were associated with greater decreases in endothelial cell density following surgery.
Conclusions
Corneal endothelial cell density significantly decreased during a 5-year follow-up after Artiflex lens implantation. The distance from the intraocular lens to the corneal endothelium, and the anterior chamber volume, were negatively correlated with the rate at which endothelial cell density decreased over time.
7.Five-year Change in Corneal Endothelial Cell Density after Foldable Iris-fixed Lens Insertion
Myungsik NAM ; David Sung Yong KANG ; Sun Woong KIM
Journal of the Korean Ophthalmological Society 2021;62(4):479-486
Purpose:
To investigate changes in corneal endothelial cell density over 5 years after implantation of Artiflex lenses (Ophtec BV, Groningen, The Netherlands) and to explore the influence of anterior chamber depth and volume on changes in endothelial cell density.
Methods:
This study included 146 eyes of 88 patients implanted with foldable phakic iris-fixation intraocular (Artiflex) lenses for myopia correction from March 2009 to March 2014. To simulate chronological changes in endothelial cell density with age, we collected normal endothelial cell density data from 100 healthy subjects aged 20, 25, or 30 years, and compared the changes among these groups at 5 years after surgery. Changes in corneal endothelial cell density were compared among four groups to which subjects were assigned based on the distance from the intraocular lens to the corneal endothelium, and the volume and depth of the preoperative anterior chamber.
Results:
The mean endothelial cell density, pre-operatively and at 1, 3, and 5 years post-operatively, was 3,038.8 ± 223.2, 2,985.3 ± 235.5, 2,905.1 ± 231.3, and 2,814.9 ± 250.5 cells/mm2, respectively (1.73%, 4.36%, and 7.31% reduction, respectively, vs. pre-operatively, p < 0.001). These differences were greater than those observed among different age groups (2.2% difference between 20- and 25-year-olds, and 1.2% difference between 25- and 30-year-olds, p < 0.001). A shorter distance from the lens to the endothelium and smaller anterior chamber volume were associated with greater decreases in endothelial cell density following surgery.
Conclusions
Corneal endothelial cell density significantly decreased during a 5-year follow-up after Artiflex lens implantation. The distance from the intraocular lens to the corneal endothelium, and the anterior chamber volume, were negatively correlated with the rate at which endothelial cell density decreased over time.
8.Impact of Baseline Ischemia on Outcome in Older Patients Undergoing Endovascular Therapy for Acute Ischemic Stroke.
Yang Ha HWANG ; Yong Won KIM ; Dong Hun KANG ; Yong Sun KIM ; David S LIEBESKIND
Journal of Clinical Neurology 2017;13(2):162-169
BACKGROUND AND PURPOSE: The outcome for older stroke patients who undergo endovascular revascularization remains unsatisfactory. We aimed to determine the effect of the extent of baseline ischemia on outcome according to age, testing the hypothesis that the restorative capacity for recovery is only marginal in older patients. METHODS: Two hundred and thirteen patients who underwent endovascular revascularization due to occlusion in the M1 segment of the middle cerebral artery (with or without internal carotid artery occlusions) were selected for analysis. Patients were categorized into three age groups: group A (<66 years), group B (66–75 years), and group C (>75 years). Using pretreatment diffusion-weighted imaging (DWI), the Alberta Stroke Program Early CT Score (ASPECTS) and lesion volume were independently measured and analyzed in relation to a favorable outcome. RESULTS: A favorable outcome was achieved in 111 of 213 patients overall: in 60 of the 94 (63.8%) patients in group A, in 36 of the 70 (51.4%) patients in group B, and in 15 of the 49 (30.6%) patients in group C (p=0.001). In older stroke patients (group C), a DWI ASPECTS ≥9 and lesion volume ≤5 mL were found to predict a favorable outcome, which was more restrictive than the cutoffs for their younger counterparts (groups A and B; DWI ASPECTS ≥8 and lesion volume ≤20 mL). CONCLUSIONS: The age-adjusted pretreatment DWI lesion volume and ASPECTS may represent useful surrogate markers for functional outcome according to age. The use of more-restrictive inclusion criteria for older stroke patients could be warranted, although larger studies are necessary to confirm these findings.
Aging
;
Alberta
;
Biomarkers
;
Carotid Artery, Internal
;
Diffusion
;
Humans
;
Ischemia*
;
Middle Cerebral Artery
;
Reperfusion
;
Stroke*
9.The activity of factor VIII and IX of cord blood at mid-trimester in fetuses without hemophilia.
David Kwang Yong CHOE ; Jeong Won OH ; Jong Kwan JUN ; Young Min CHOI
Journal of Genetic Medicine 2016;13(2):89-94
PURPOSE: Molecular genetic analysis is the main approach used for prenatal diagnosis of hemophilia A and B. However, in certain cases, such analysis is uninformative. In such situations, direct measurement of fetal coagulation factor levels is still the best option, and it may be the only option in some cases. This study was conducted to determine the normal ranges of midtrimester cord blood factor VIII (FVIII) and IX (FIX) in a Korean population. MATERIALS AND METHODS: Twenty-six FVIII samples and 29 FIX samples were assayed in fetal cord blood acquired by ultrasound-guided cordocentesis. Sampling was conducted during gestational ages of 19-24 weeks. RESULTS: The mean and standard deviations for FVIII and FIX activity were 45.5±30.5% and 19.9±12.2%, respectively. Ranges for FVIII and FIX were 1.5-125.0% and 6.0-52.0%, respectively. CONCLUSION: Our study revealed the normal ranges and lowest level of factor VIII and factor IX in non-affected normal fetus by fetal cord blood sampling during the mid-trimester in a Korea population. The factor assay of the fetal cord blood is invasive but feasible and provides important basic data related to hemophilia.
Blood Coagulation Factors
;
Cordocentesis
;
Factor IX
;
Factor VIII*
;
Female
;
Fetal Blood*
;
Fetus*
;
Gestational Age
;
Hemophilia A*
;
Humans
;
Korea
;
Molecular Biology
;
Pregnancy
;
Pregnancy Trimester, Second
;
Prenatal Diagnosis
;
Reference Values
10.Diabetes Management and Hypoglycemia in Safety Sensitive Jobs.
See Muah LEE ; David KOH ; Winnie KL CHUI ; Chee Fang SUM
Safety and Health at Work 2011;2(1):9-16
The majority of people diagnosed with diabetes mellitus are in the working age group in developing countries. The interrelationship of diabetes and work, that is, diabetes affecting work and work affecting diabetes, becomes an important issue for these people. Therapeutic options for the diabetic worker have been developed, and currently include various insulins, insulin sensitizers and secretagogues, incretin mimetics and enhancers, and alpha glucosidase inhibitors. Hypoglycemia and hypoglycaemic unawareness are important and unwanted treatment side effects. The risk they pose with respect to cognitive impairment can have safety implications. The understanding of the therapeutic options in the management of diabetic workers, blood glucose awareness training, and self-monitoring blood glucose will help to mitigate this risk. Employment decisions must also take into account the extent to which the jobs performed by the worker are safety sensitive. A risk assessment matrix, based on the extent to which a job is considered safety sensitive and based on the severity of the hypoglycaemia, may assist in determining one's fitness to work. Support at the workplace, such as a provision of healthy food options and arrangements for affected workers will be helpful for such workers. Arrangements include permission to carry and consume emergency sugar, flexible meal times, self-monitoring blood glucose when required, storage/disposal facilities for medicine such as insulin and needles, time off for medical appointments, and structured self-help programs.
alpha-Glucosidases
;
Appointments and Schedules
;
Blood Glucose
;
Developing Countries
;
Diabetes Mellitus
;
Emergencies
;
Employment
;
Humans
;
Hypoglycemia
;
Incretins
;
Insulin
;
Insulins
;
Meals
;
Needles
;
Risk Assessment