Background: Glenoid position and inclination are important factors in protecting against scapular notching, which is the most common complication that directly affects the longevity of reverse shoulder arthroplasty (RSA). This study aimed to investigate the biomechanical characteristics of glenosphere orientation, comparing neutral tilt, inferior overhang with an eccentric glenosphere at the same placement of baseplate, and inferior tilt after 10° inferior reaming in the lower part of the glenoid in RSA. Methods: Nine cadaveric shoulders were tested with 5 combinations of customized glenoid components: a centric glenosphere was combined with a standard baseplate (group A); an eccentric glenosphere to provide 4-mm inferior overhang than the centric glenosphere was combined with a standard baseplate (group B); a centric glenosphere was combined with a wedge-shaped baseplate tilted inferiorly by 10° with the same center of rotation (group C); an eccentric glenosphere was attached to a wedge-shaped baseplate (group D); and 10° inferior reaming was performed on the lower part of the glenoid to apply 10° inferior tilt, with a centric glenosphere secured to the standard baseplate for simulation of clinical tilt (group E). Impingement-free angles for adduction, abduction, forward flexion, external rotation, and internal rotation were measured. The capability of the deltoid moment arm for abduction and forward flexion, deltoid length, and geometric analysis for adduction engagement were evaluated. Results: Compared with neutral tilt, inferior tilt at the same position showed no significant difference in impingement-free angle, moment arm capability, and deltoid length. However, group D resulted in better biomechanical properties than a central position, regardless of inferior tilt. Group E demonstrated a greater range of adduction, internal and external rotation, and higher abduction and forward flexion capability with distalization, compared to corresponding parameters for inferior tilt with a customized wedgeshaped baseplate. Conclusions A 10° inferior tilt of the glenosphere, without changing the position of the baseplate, had no benefit in terms of the impingement-free angle and deltoid moment arm. However, an eccentric glenosphere had a significant advantage, regardless of inferior tilt. Inferior tilt through 10° inferior reaming showed better biomechanical results than neutral tilt due to the distalization effect.

Background: Disruption of the rotator cuff muscles compromises concavity compression force, which leads to superior migration of the humeral head and loss of stability. A novel idea of using the magnetic force to achieve shoulder stabilization in massive rotator cuff tears (MRCTs) was considered because the magnets can stabilize two separate entities with an attraction force. This study aimed to investigate the biomechanical effect of the magnetic force on shoulder stabilization in MRCTs. Methods: Seven fresh frozen cadaveric specimens were used with a customized shoulder testing system. Three testing conditions were set up: condition 1, intact rotator cuff without magnets; condition 2, an MRCT without magnets; condition 3, an MRCT with magnets. For each condition, anterior-posterior translation, superior translation, superior migration, and subacromial contact pressure were measured at 0°, 30°, and 60° of abduction. The abduction capability of condition 2 was compared with that of condition 3. Results: The anterior-posterior and superior translations increased in condition 2; however, they decreased compared to condition 2 when the magnets were applied (condition 3) in multiple test positions and loadings (p <0.05). Abduction capability improved significantly in condition 3 compared with that in condition 2, even for less deltoid loading (p < 0.05). Conclusions The magnet biomechanically played a positive role in stabilizing the shoulder joint and enabled abduction with less deltoid force in MRCTs. However, to ensure that the magnet is clinically applicable as a stabilizer for the shoulder joint, it is necessary to thoroughly verify its safety in the human body and to conduct further research on technical challenges.

BACKGROUND: In 2010, the Clinical and Laboratory Standards Institute (CLSI) revised the minimum inhibitory concentration (MIC) breakpoints of cephalosporins and aztreonam to exempt extended-spectrum beta-lactamase (ESBL) confirmatory tests for Enterobacteriaceae. However, the CLSI did not change the MIC breakpoint of cefepime. Here, a proficiency survey of a strain of ESBL-producing Klebsiella pneumoniae was analyzed for MIC distribution and interpretation of cephalosporins and aztreonam. METHODS: The survey strain, K. pneumoniae, which produced SHV-18, was distributed to 170 clinical laboratories as 1 of 5 presumptive clinical specimens through the proficiency survey of the clinical microbiology division of the Korean Association of Quality Assurance for Clinical Laboratories (KAQACL). MIC, zone diameter of inhibition (ZDI), and interpretation of tested antimicrobials, methods of antimicrobial susceptibility testing (AST), and ESBL confirmatory results were collected. RESULTS: According to the revised breakpoints of the 2010 CLSI guidelines, MIC results indicated resistance to aztreonam in 100%, cefepime in 5.5%, cefotaxime in 20%, ceftazidime in 100%, and ceftriaxone in 100% of samples by broth microdilution methods. ZDI results also indicated resistance to aztreonam in 75%, cefepime in 0%, cefotaxime in 66.7%, ceftazidime in 100%, and ceftriaxone in 80% of samples by disk diffusion method. Ninety (75.6%) participants performed an ESBL confirmatory test, and 89 (98.9%) reported ESBL-positive tests. Of the 55 laboratories that tested the susceptibility of cefepime, 50 (90.9%) self-reported to be "resistant" because of ESBL-positive results. CONCLUSIONS: In conclusion, susceptibility testing of ESBL producers against certain cephalosporins is not reliable enough to apply the revised breakpoints presented in the 2010 CLSI guidelines. It is therefore necessary to reach a consensus for interpretation of ASTs of ESBL producers in Korea. Ideally, clinicians should be provided two interpretations based on both the revised breakpoints and ESBL confirmatory testing.
Aztreonam ; beta-Lactamases ; Cefotaxime ; Ceftazidime ; Ceftriaxone ; Cephalosporins ; Consensus ; Diffusion ; Enterobacteriaceae ; Klebsiella ; Klebsiella pneumoniae ; Korea ; Microbial Sensitivity Tests ; Pneumonia ; Sprains and Strains

BACKGROUND: To ensure safety of blood transfusion, accuracy in performance of blood grouping tests (BGT) is essential. External proficiency testing (PT) for BGT has not been conducted in Korea. The first PT for BGT in domestic blood centers was conducted in order to evaluate the domestic status of accuracy of BGT in blood centers and to aid in improving the quality of blood centers. METHODS: Whole blood survey specimens consisting of three panels for ABO grouping and two panels for Rh typing were sent to 81 blood centers. Evaluation criteria for BGT were as follows: 'Good' for answers with 100% referee consensus, 'Acceptable' for correct answers other than those of the referee, and 'Unacceptable' for answers other than those of 'Good+acceptable' as correct answers. RESULTS: Rates of correct answers on three panels for ABO grouping were all 100%; however, that of cell typing for the panel with BW was 61.7%, and 31 blood centers incorrectly reported normal 'B' type as an answer. The rate of correct answers for the Rh negative panel was 100%; however, that for the weak D panel was 84%, and 13 blood centers incorrectly reported Rh negative type as an answer. CONCLUSION: Findings from this study demonstrated that some hospital blood centers were not able to correctly detect blood groups with weak antigens. Therefore, to improve the quality of blood centers, intensive education for blood center staff and continued PT for BGT should be required.
Blood Group Antigens ; Blood Grouping and Crossmatching ; Blood Transfusion ; Consensus ; Dietary Sucrose ; Korea

BACKGROUND: We evaluated the performance of multiplex tandem mass spectrometry (MS/MS) in newborn screening for detection of 6 lysosomal storage disorders (LSDs), namely, Niemann-Pick A/B, Krabbe, Gaucher, Fabry, and Pompe diseases and Hurler syndrome. METHODS: We revised the conditions and procedures of multiplex enzyme assay for the MS/MS analysis and determined the precision of our enzyme assay and the effects of sample amounts and incubation time on the results. We also measured the degree of correlation between the enzyme activities in the dried blood spots (DBSs) and those in the leukocytes. DBSs of 211 normal newborns and 13 newborns with various LSDs were analyzed using our revised methods. RESULTS: The intra- and inter-assay precisions were 2.9-18.7% and 8.1-18.1%, respectively. The amount of product obtained was proportional to the DBS eluate volume, but a slight flattening was observed in the product vs. sample volume curve at higher sample volumes. For each enzyme assay, the amount of product obtained increased linearly with the incubation period (range, 0-24 hr). Passing and Bablok regression analysis revealed that the enzyme activities in the DBSs and those in the leukocytes were favorably correlated. The enzyme activities measured in the DBSs were consistently lower in patients with LSDs than in normal newborns. CONCLUSIONS: The performance of our revised techniques for MS/MS detection and enzyme assays was of the generally acceptable standard. To our knowledge, this is the first report on the use of MS/MS for newborn screening of LSDs in an Asian population.
Dried Blood Spot Testing ; Enzyme Assays ; Enzymes/blood ; Humans ; Infant, Newborn ; Leukocytes/enzymology ; Lysosomal Storage Diseases/*diagnosis ; Republic of Korea ; Tandem Mass Spectrometry/*methods ; Time Factors

BACKGROUND: Insulin assays are affected by varying degrees of interference from anti-insulin antibodies (IAs) and by cross-reactivity with recombinant insulin analogues. We evaluated the usefulness of the E170 insulin assay by assessing IA effects and cross-reactivity with 2 analogues. METHODS: Sera were obtained from 59 type 2 diabetes patients receiving continuous subcutaneous insulin infusion and 18 healthy controls. Insulin levels were determined using an E170 analyzer. To investigate the effects of IAs, we performed IA radioimmunoassays, and analyzed the differences between directly measured insulin (direct insulin) and polyethylene glycol (PEG)-treated insulins (free, IA-unbound; total, IA-bound and unbound insulin). We performed in-vitro cross-reactivity tests with insulin aspart and insulin glulisine. RESULTS: In IA-positive patients, E170 free insulin levels measured using the E170 analyzer were significantly lower than the direct insulin levels. The mean value of the direct/free insulin ratio and IA-bound insulin, which were calculated as the difference between total and free insulin, increased significantly as endogenous IA levels increased. The E170 insulin assay showed low cross-reactivities with both analogues (< 0.7%). CONCLUSIONS: IAs interfered with E170 insulin assay, and the extent of interference correlated with the IA levels, which may be attributable to the increase in IA-bound insulin, and not to an error in the assay. The E170 insulin assay may measure only endogenous insulin since cross-reactivity is low. Our results suggest that the measurement of free insulin after PEG pre-treatment could be useful for beta cell function assessment in diabetic patients undergoing insulin therapy.
Adult ; Aged ; Aged, 80 and over ; Cross Reactions ; Diabetes Mellitus, Type 2/blood/immunology ; Female ; Humans ; Infusions, Subcutaneous ; Insulin/analogs & derivatives/*blood/chemistry/immunology ; Insulin Antibodies/*blood ; Male ; Middle Aged ; Polyethylene Glycols/chemistry ; Radioimmunoassay/instrumentation/*methods ; Recombinant Proteins/analysis/immunology/metabolism

BACKGROUND: The Lewis histo-blood group system consists of 2 major antigens-Lea and Leb-and a sialyl Lewis antigen-carbohydrate antigen (CA) 19-9. We investigated the distribution of Lewis genotypes and evaluated the relationship between the Lewis/Secretor genotypes and the serum level of CA 19-9 in a Korean population to identify whether the serum CA 19-9 levels are influenced by the Lewis/Secretor genotypes. METHODS: The study included 242 individuals who had no malignancies. Lewis genotyping was performed for the 59T>G, 508G>A and 1067T>A polymorphic sites. The Secretor genotype was determined through analysis of the 357C>T and 385A>T polymorphic sites and the fusion gene. Serum CA 19-9 level was analyzed using an electrochemiluminescence immunoassay. RESULTS: Individuals carrying the 3 common genotypes-Le/Le, Le/le(59,508), and Le/le(59,1067)-accounted for 95% of the study population. In the Korean population, the allelic frequencies of Le, Le(59), le(59,508), and le(59,1067) were 0.731, 0.010, 0.223, and 0.035, respectively. We found a significant difference in serum CA 19-9 concentrations among the 9 Lewis/Secretor genotype groups (P<0.001). The serum CA 19-9 levels in subjects with genotype groups 1 and 2 (Le/- and se/se) were higher than those with genotype groups 3-6 (Le/- and Se/-; 15.63 vs 6.64 kU/L, P<0.001). CONCLUSIONS: Le/Le, Le/le(59,508), and Le/le(59,1067) are frequent Lewis genotypes in Koreans. Because serum CA 19-9 levels are significantly influenced by the Lewis/Secretor genotypes, caution is suggested when interpreting the serum CA 19-9 levels.
Adult ; Aged ; Alleles ; Asian Continental Ancestry Group/*genetics ; CA-19-9 Antigen/*blood ; Chemiluminescent Measurements/methods ; Female ; Gene Frequency ; Genotype ; Humans ; Immunoassay/methods ; Lewis Blood-Group System/*genetics ; Male ; Middle Aged ; Phenotype ; Polymorphism, Genetic ; Republic of Korea

BACKGROUND: To prevent blood-borne infections and guarantee safe transfusion, we proposed a quality assurance program for donor screening tests, such as hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus antibody (anti-HCV), by introducing external proficiency testing for the laboratories that perform donor screening tests. METHODS: The materials for external proficiency testing (PT) were prepared from the HBsAg Standard Panels and anti-HCV Reference Panels provided by the Korea Food and Drug Administration (KFDA), and the normal Human Serum was provided by the Serum Bank of the Korea National Research Resource Center. The external PT materials were sent to 83 laboratories that performed donor screening tests after evaluating their quality. RESULTS: The results of evaluating the quality of the PT materials were acceptable. All the laboratories receiving the materials answered with a 100% response rate. All the laboratories answered that they obtained positive results for the HBsAg Standard Panel E, H, I and J; however, one laboratory answered in the gray-zone and that lab had negative results for HBsAg Standard Panel C and G. Seventy laboratories (84%) and 42 laboratories (51%) among the total 83 laboratories answered they had positive results for HBsAg Standard Panel B and D, suggesting that many laboratories could not detect a low level of HBsAg. All 83 laboratories answered that they had concordant results for the external PT for anti-HCV. CONCLUSION: Donor screening laboratories can detect low levels of HBsAg and anti-HCV without any errors and the performance of the laboratories that could not detect low levels of HBsAg remains to be improved. Quality assurance program using external PT with materials that contain various genotypes and mutants should be conducted to maintain the quality of donor screening tests.
Blood Donors ; Donor Selection ; Genotype ; Hepatitis B Surface Antigens ; Humans ; Korea ; Mass Screening ; Pyridines ; Thiazoles ; United States Food and Drug Administration ; Viruses

Six trials with 3 samples for each trial for external quality assessment of general chemistry and blood gas were performed in 2009. All the control materials were sent in specifically-made boxes at the same time. The response rates were 87.5% in general chemistry and 89.3% in blood gas. The items included sodium, potassium, chloride, BUN, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, total cholesterol, triglyceride, AST, ALT, ALP, LD and GGT in general chemistry and pH, pCO2 and pO2 in blood gas. Compared with the previous year (2008), change of the methods of analysis was not remarkable. The peer group coefficient of variation and the VIS scores of general chemistry items were slightly improved.
Bilirubin ; Calcium ; Chemistry, Clinical ; Cholesterol ; Creatinine ; Glucose ; Hydrogen-Ion Concentration ; Korea ; Peer Group ; Phosphorus ; Potassium ; Sodium ; Uric Acid

BACKGROUND: Hemoglobin A1c (HbA1c) is widely used for the monitoring of glycemic control in diabetes mellitus patients. Various methods are applied for the determination of HbA1c levels. Recently, a novel National Glycohemoglobin Standardization Program (NGSP)-certificated reagent (AutoLab HbA1c, IVD-LAB, Korea) was introduced for use in an automated chemistry analyzer. We evaluated the analytical performance of this immunoturbidimetry reagent and compared it with the ion-exchange high performance liquid chromatography (Variant II Turbo, Bio-Rad Laboratories, Inc., USA) and immunoassay (Cobas Integra 800, Roche Diagnostics, Germany) methods. METHODS: Toshiba 200FR NEO (Toshiba Medical Systems Co., Japan) with the AutoLab reagent was evaluated for precision, linearity, carryover and compared with Cobas Integra and Variant II Turbo. RESULTS: Coefficients of variation (CVs) of within-run imprecision for low and high level were 1.8% and 0.7%, respectively. CVs of within-laboratory imprecision for low and high level were 2.4% and 1.0%, respectively. The linearity was excellent with R2 = 0.99 in the range of 3.05-15.50%. It was well correlated with Variant II Turbo (R=0.9904) and Cobas Integra 800 (R=0.9992). The carryover rate was 0.4%. CONCLUSIONS: The Toshiba 200FR NEO with the AutoLab reagent showed excellent precision and linearity and minimal carryover rate. It was well correlated with the other widely used methodological instruments. It may be used for the diagnosis and the treatment monitoring of diabetes.
Chromatography, Liquid ; Diabetes Mellitus ; Hemoglobins ; Humans ; Immunoassay