The present review presents basic concepts of blood rheology related to vascular diseases. Blood flow in large arteries is dominated by inertial forces exhibited at high flow velocities, while viscous forces (i.e., blood rheology) play an almost negligible role. When high flow velocity is compromised by sudden deceleration as at a bifurcation, endothelial cell dysfunction can occur along the outer wall of the bifurcation, initiating inflammatory gene expression and, through mechanotransduction, the cascade of events associated with atherosclerosis. In sharp contrast, the flow of blood in microvessels is dominated by viscous shear forces since the inertial forces are negligible due to low flow velocities. Shear stress is a critical parameter in microvascular flow, and a force-balance approach is proposed for determining microvascular shear stress, accounting for the low Reynolds numbers and the dominance of viscous forces over inertial forces. Accordingly, when the attractive forces between erythrocytes (represented by the yield stress of blood) are greater than the shear force produced by microvascular flow, tissue perfusion itself cannot be sustained, leading to capillary loss. The yield stress parameter is presented as a diagnostic candidate for future clinical research, specifically, as a fluid dynamic biomarker for microvascular disorders. The relation between the yield stress and diastolic blood viscosity (DBV) is described using the Casson model for viscosity, from which one may be able determine thresholds of DBV where the risk of microvascular disorders is high.
Accounting ; Arteries ; Atherosclerosis ; Blood Viscosity ; Capillaries ; Deceleration ; Endothelial Cells ; Erythrocytes ; Gene Expression ; Hemorheology ; Hydrodynamics ; Microvascular Angina ; Microvessels ; Perfusion ; Rheology ; Vascular Diseases ; Viscosity

Podcasts are increasingly being used for medical education, both within teaching institutions and on an international scale by major journals. To date, there are no evidence-based guidelines for the development of educational podcasts. To review the state of the literature, MEDLINE, SCOPUS, and ERIC were searched in May 2016 for articles describing audio format podcasts used in medical education. Eighty-four articles met inclusion criteria. A qualitative synthesis of the evidence was done using Kirkpatrick’s model for evaluating outcomes. Twenty-four articles described reaction outcomes, eleven described learning outcomes, and one described behavioral outcomes. None measured patient impact. The literature demonstrates that podcasts are both feasible and accepted by learners. The mean length of reported podcasts was 18 minutes, which falls within the recommended range in at least one paper, and is consistent with reported listener preference. Interview format, clear disclosures, and accurate information were reported as desirable. There is limited evidence showing the efficacy of podcasts as teaching tools, or regarding best practices in making podcasts. More rigorous studies evaluating efficacy, changes in behavior, and changes in patient outcomes need to be performed in order to prove podcasts’ value and to justify production costs.
Accidental Falls ; Education, Medical* ; Education, Medical, Continuing ; Education, Medical, Graduate ; Humans ; Learning ; Practice Guidelines as Topic ; Webcasts as Topic

BACKGROUND: Mental health issues such as stress and depression have been regarded as major social problems in Korea. We investigated the relationship between stress and depression with unmet medical needs (UMN). METHODS: Using the nationwide database of 2010 Korea National Health and Nutritional Examination Survey (K-NHANES), subjects aged 19 years or above were selected (n=6,055). In the K-NHANES questionnaire, subjects were asked about their UMN experience, severity of stress, and perceived depression lasting at least 2 weeks over the past year. The effects of stress and depression on UMN were analyzed in 4 models established by adding predisposing, enabling and need factors in a step-wise fashion. The risks for UMN were also assessed according to the causes of UMN. RESULTS: Individuals who felt stress ‘very often’ (odds ratio (OR) 3.28, 95% CI=2.23-4.86) and ‘often’ (OR 2.53, 95% CI=1.93-3.31) and who experienced depression (OR 1.68, 95% CI=1.35-2.10) reported significantly elevated UMN rates, and these effects were substantial especially for the individuals who had UMN due to economic constraint. Females, lower education level, lower income, unemployed status, and negative perceptions about health status were found to be additional risk factors for UMN. CONCLUSION: Our results confirmed the risks of stress and depression on UMN. It is strongly advisable to create initiatives to improve mental health, particularly stress and depression, and to fulfill individuals' medical utilization needs.
Depression* ; Education ; Female ; Humans ; Korea ; Mental Health ; Risk Factors ; Social Problems

BACKGROUND: Tosufloxacin is one of the fluoroquinolones with higher antibacterial activity against many organisms than other fluoroquinolones developed previously. However, the antimicrobial susceptibilities of tosufloxacin against uropathogens are not well known. The objective of this study was to compare minimum inhibitory concentrations (MICs) of tosufloxacin with those of levofloxacin and ofloxacin for uropathogens cultured from the urine of female outpatients with acute uncomplicated cystitis. MATERIALS AND METHODS: We collected and cultured urine samples from four metropolitan hospitals between August 2006 and November 2006. The MICs of tosufloxacin, levofloxacin and ofloxacin were determined for 89 isolates using an agar dilution method. RESULTS: The most prevalent causative organism was Escherichia coli (70.8%). The MIC distribution of tosufloxacin and levofloxacin showed a bimodal distribution for E. coli. The two modes for E. coli were 0.03 and 32 microgram/mL for tosufloxacin and 0.03 and 16 microgram/mL for levofloxacin. However, ofloxacin had one more peak at MIC 0.5 microgram/mL. MIC50s of tosufloxacin, levofloxacin and ofloxacin for E. coli were 0.03 microgram/mL, 0.06 microgram/mL and 0.125 microgram/mL, respectively. Tosufloxacin, the newer fluoroquinolone, was more active than levofloxacin and ofloxacin against both E. coli and Gram-positive bacteria. CONCLUSION: Of the studied fluoroquinolones tosufloxacin had the lowest MICs against uropathogens and could be considered a promising alternative fluoroquinolone agent for the treatment of urinary tract infection.
Agar ; Cystitis* ; Escherichia coli ; Female* ; Fluoroquinolones ; Gram-Positive Bacteria ; Hospitals, Urban ; Humans ; Levofloxacin* ; Microbial Sensitivity Tests ; Ofloxacin* ; Outpatients* ; Urinary Tract Infections

BACKGROUND: Tosufloxacin is one of the fluoroquinolones with higher antibacterial activity against many organisms than other fluoroquinolones developed previously. However, the antimicrobial susceptibilities of tosufloxacin against uropathogens are not well known. The objective of this study was to compare minimum inhibitory concentrations (MICs) of tosufloxacin with those of levofloxacin and ofloxacin for uropathogens cultured from the urine of female outpatients with acute uncomplicated cystitis. MATERIALS AND METHODS: We collected and cultured urine samples from four metropolitan hospitals between August 2006 and November 2006. The MICs of tosufloxacin, levofloxacin and ofloxacin were determined for 89 isolates using an agar dilution method. RESULTS: The most prevalent causative organism was Escherichia coli (70.8%). The MIC distribution of tosufloxacin and levofloxacin showed a bimodal distribution for E. coli. The two modes for E. coli were 0.03 and 32 microgram/mL for tosufloxacin and 0.03 and 16 microgram/mL for levofloxacin. However, ofloxacin had one more peak at MIC 0.5 microgram/mL. MIC50s of tosufloxacin, levofloxacin and ofloxacin for E. coli were 0.03 microgram/mL, 0.06 microgram/mL and 0.125 microgram/mL, respectively. Tosufloxacin, the newer fluoroquinolone, was more active than levofloxacin and ofloxacin against both E. coli and Gram-positive bacteria. CONCLUSION: Of the studied fluoroquinolones tosufloxacin had the lowest MICs against uropathogens and could be considered a promising alternative fluoroquinolone agent for the treatment of urinary tract infection.
Agar ; Cystitis* ; Escherichia coli ; Female* ; Fluoroquinolones ; Gram-Positive Bacteria ; Hospitals, Urban ; Humans ; Levofloxacin* ; Microbial Sensitivity Tests ; Ofloxacin* ; Outpatients* ; Urinary Tract Infections

BACKGROUND: IgE is closely related to the development of allergies. However, the poor relationship between the specific IgE level and the severity of allergic diseases suggests the possibility of functionally different IgE isoforms. With this in mind, rat basophilic leukemia (RBL)-2H3 activation was analyzed with each type of rat IgE for two parameters, exocytosis and IL-4 mRNA production. RBL-2H3 has been well documented in the rat mucosal mast cell line. METHODS: RBL-2H3 cells sensitized with each kind of rat IgE was activated by cross-linking FcRI with B5 (monoclonal anti-rat IgE mouse IgG antibodies). The RBL-2H3 exocytosis was measured by analyzing the beta-hexosaminidase level, and the level of IL-4 mRNA synthesis was analyzed using semi- quantitative RT-PCR. Rat IgE, which was produced by a parasite infection (REP), was prepared using either Paragonimus westermani metacercariae (REP-PW) or Anisakis simplex third stage larvae (REP-AS). A rat IgE prototype of IR162 was prepared by a peritoneal injection of immunocytoma. RESULTS: The level of exocytosis showed a linear relationship with the rat IgE concentration when REP-PW or REP-AS was applied. However, it exhibited a biphasic response with IR162. In addition, the time course of heating at 56oC illustrated the similarity between REP-PW and REP-AS, which differed from that of IR162. In contrast, the level of IL-4 mRNA synthesis in the RBL-2H3 cells with IR162 was comparable to that of either REP-PW or REP-AS. CONCLUSION: These results suggest that functionally different rat IgE isoforms exists in RBL-2H3 exocytosis.
Animals ; Anisakis ; Basophils ; beta-N-Acetylhexosaminidases ; Exocytosis* ; Heating ; Hot Temperature ; Hypersensitivity ; Immunoglobulin E* ; Immunoglobulin G ; Interleukin-4 ; Larva ; Leukemia ; Mast Cells ; Metacercariae ; Mice ; Paragonimus westermani ; Parasites ; Protein Isoforms ; Rats* ; RNA, Messenger

PURPOSE: To efficiently evaluate phased array coil performance using a software tool box with which we can make visual comparison of the sensitivity of every coil element between the real experiment and EM simulation. MATERIALS AND METHODS: We have developed a C++- and MATLAB-based software tool called Phased Array Coil Evaluator (PACE). PACE has the following functions: Building 3D models of the coil elements, importing the FDTD simulation results, and visualizing the coil sensitivity of each coil element on the ordinary Cartesian coordinate and the relative coil position coordinate. To build a 3D model of the phased array coil, we used an electromagnetic 3D tracker in a stylus form. After making the 3D model, we imported the 3D model into the FDTD electromagnetic field simulation tool. RESULTS: An accurate comparison between the coil sensitivity simulation and real experiment on the tool box platform has been made through fine matching of the simulation and real experiment with aids of the 3D tracker. In the simulation and experiment, we used a 36-channel helmet-style phased array coil. At the 3D MRI data acquisition using the spoiled gradient echo sequence, we used the uniform cylindrical phantom that had the same geometry as the one in the FDTD simulation. In the tool box, we can conveniently choose the coil element of interest and we can compare the coil sensitivities element-by-element of the phased array coil. CONCLUSION: We expect the tool box can be greatly used for developing phased array coils of new geometry or for periodic maintenance of phased array coils in a more accurate and consistent manner.
Electromagnetic Fields ; Magnetic Resonance Imaging ; Magnets ; Retrospective Studies*

A systematic review of English and Korean articles published between 1990 and 2004 and a search of database and various online resources was conducted to determine the prevalences, mortality rates, socioeconomic burden, quality of life, and treatment pattern of asthma in Korean adults and children. Asthma morbidity and mortality in Korea are steadily increasing. The prevalence of asthma in Korea is estimated to be 3.9% and its severity is often underestimated by both physicians and patients. Mortality resulting from chronic lower respiratory diseases including asthma increased from 12.9 to 22.6 deaths per 100,000 of the population between 1992 and 2002. Disease severity, level of control, and symptom state were all found to negatively impact the quality of life of asthmatics. Although international and Korean asthma management guidelines are available, familiarity with and implementation of these guidelines by primary care physicians remain poor.
Risk Factors ; Quality of Life ; Practice Guidelines ; Korea/epidemiology ; Humans ; Costs and Cost Analysis ; Child ; *Asthma/economics/epidemiology/mortality/therapy ; Adult

Dermatofibrosarcoma protuberans (DFSP) typically presents during the early or mid-adult life, and the most common site of origin is the skin on the trunk and proximal extremities. DFSP of the parotid gland is extremely rare and only one case has been reported in the literature. We present here a case of a 30-year-old woman with DFSP occurring in the parotid gland, and we discuss the differential diagnosis. The patient is alive and doing well one year after her operation.
Adult ; Dermatofibrosarcoma* ; Diagnosis, Differential ; Extremities ; Female ; Humans ; Parotid Gland* ; Skin

Objective: We compared appendiceal visualization on 2-mSv CT vs. conventional-dose CT (median 7 mSv) in adolescents and young adults and analyzed the undesirable clinical and diagnostic outcomes that followed appendiceal nonvisualization. Materials and Methods: A total of 3074 patients aged 15–44 years (mean ± standard deviation, 28 ± 9 years; 1672 female) from 20 hospitals were randomized to the 2-mSv CT or conventional-dose CT group (1535 vs. 1539) from December 2013 through August 2016. A total of 161 radiologists from 20 institutions prospectively rated appendiceal visualization (grade 0, not identified; grade 1, unsure or partly visualized; and grade 2, clearly and entirely visualized) and the presence of appendicitis in these patients. The final diagnosis was based on CT imaging and surgical, pathologic, and clinical findings. We analyzed undesirable clinical or diagnostic outcomes, such as negative appendectomy, perforated appendicitis, more extensive than simple appendectomy, delay in patient management, or incorrect CT diagnosis, which followed appendiceal nonvisualization (defined as grade 0 or 1) and compared the outcomes between the two groups. Results: In the 2-mSv CT and conventional-dose CT groups, appendiceal visualization was rated as grade 0 in 41 (2.7%) and 18 (1.2%) patients, respectively; grade 1 in 181 (11.8%) and 81 (5.3%) patients, respectively; and grade 2 in 1304 (85.0%) and 1421 (92.3%) patients, respectively (p < 0.001). Overall, undesirable outcomes were rare in both groups. Compared to the conventional-dose CT group, the 2-mSv CT group had slightly higher rates of perforated appendicitis (1.1% [17] vs. 0.5% [7], p = 0.06) and false-negative diagnoses (0.4% [6] vs. 0.0% [0], p = 0.01) following appendiceal nonvisualization. Otherwise, these two groups were comparable. Conclusion The use of 2-mSv CT instead of conventional-dose CT impairs appendiceal visualization in more patients. However, appendiceal nonvisualization on 2-mSv CT rarely leads to undesirable clinical or diagnostic outcomes.