PURPOSE: The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value. MATERIALS AND METHODS: Two types of three-dimensional models for the mandibular first molar were designed: bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions: 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed. RESULTS: The stress values in the implant were as follows: 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°. CONCLUSION The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.

PURPOSE: Lung Cancer Subcommittee of Korean Radiation Oncology Group (KROG) has recently launched a prospective clinical trial (KROG 17-06) of hippocampus-sparing whole brain radiotherapy (HS-WBRT) with simultaneous integrated boost (SIB) in treating multiple brain metastases from non-small cell lung cancer. In order to improve trial quality, dummy run studies among the participating institutions were designed. This work reported the results of two-step dummy run procedures of the KROG 17-06 study. MATERIALS AND METHODS: Two steps tested hippocampus contouring variability and radiation therapy planning compliance. In the first step, the variation of the hippocampus delineation was investigated for two representative cases using the Dice similarity coefficients. In the second step, the participating institutions were requested to generate a HS-WBRT with SIB treatment plan for another representative case. The compliance of the treatment plans to the planning protocol was evaluated. RESULTS: In the first step, the median Dice similarity coefficients of the hippocampus contours for two other dummy run cases changed from 0.669 (range, 0.073 to 0.712) to 0.690 (range, 0.522 to 0.750) and from 0.291 (range, 0.219 to 0.522) to 0.412 (range, 0.264 to 0.598) after providing the hippocampus contouring feedback. In the second step, with providing additional plan priority and extended dose constraints to the target volumes and normal structures, we observed the improved compliance of the treatment plans to the planning protocol. CONCLUSION: The dummy run studies demonstrated the notable inter-institutional variability in delineating the hippocampus and treatment plan generation, which could be decreased through feedback from the trial center.
Brain ; Carcinoma, Non-Small-Cell Lung ; Compliance ; Hippocampus ; Lung Neoplasms ; Neoplasm Metastasis ; Prospective Studies ; Radiation Oncology ; Radiotherapy

The porcine reproductive and respiratory syndrome virus (PRRSV) is a globally ubiquitous swine viral pathogen that causes major economic losses worldwide. We previously reported an over-attenuated phenotype of cell-adapted PRRSV strain CA-2-P100 in vivo. In the present study, CA-2-P100 was serially propagated in cultured porcine alveolar macrophage (PAM) cells for up to 20 passages to obtain the derivative strain CA-2-MP120. Animal inoculation studies revealed that both CA-2-P100 and CA-2-MP120 had decreased virulence, eliciting weight gains, body temperatures, and histopathologic lesions similar to those in the negative control group. However, compared to CA-2-P100 infection, CA-2-MP120 yielded consistently higher viremia kinetics and enhanced antibody responses in pigs. All pigs inoculated with CA-2-MP120 developed viremia and seroconverted to PRRSV. During 20 passages in PAM cells, CA-2-MP120 acquired 15 amino acid changes that were mostly distributed in nsp2 and minor structural protein-coding regions. Among these changes, 6 mutations represented reversions to the sequences of the reference CA-2 and parental CA-2-P20 strains. These genetic drifts may be hypothetical molecular markers associated with PRRSV macrophage tropism and virulence. Our results indicate that the PAM-passaged CA-2-MP120 strain is a potential candidate for developing a live, attenuated PRRSV vaccine.
Animals ; Antibody Formation ; Body Temperature ; Genetic Drift ; Humans ; Kinetics ; Macrophages ; Macrophages, Alveolar ; Parents ; Phenotype ; Porcine Reproductive and Respiratory Syndrome ; Porcine respiratory and reproductive syndrome virus ; Swine ; Tropism ; Vaccines, Attenuated ; Viremia ; Virulence ; Weight Gain

Milk-alkali syndrome (MAS), a triad of hypercalcemia, metabolic alkalosis, and renal failure, is associated with ingestion of large amounts of calcium and absorbable alkali. MAS is the third most common cause of hypercalcemia in hospital, after primary hyperparathyroidism and malignant neoplasm. MAS is not often reported in the Korean literature. We describe MAS secondary to intake of calcium citrate for the treatment of osteoporosis with thoracic spine compression fracture. A 70-year-old man presented to our hospital with a 1-week history of general weakness and lethargy. He was found with acute kidney injury (serum creatinine, 4.6 mg/dL), hypercalcemia (total calcium, 14.8 mg/dL), and alkalosis. Laboratory evaluation excluded both hyperparathyroidism and malignancy. Mental status and serum calcium level was normalized within a week after proper hydration and intravenous administration of furosemide. However, he developed aspiration pneumonia, pseudomembranous colitis, and sepsis with multi-organ failure. Despite intensive treatment including inotropics, mechanical ventilation, and renal replacement therapy, he expired with no signs of renal recovery on the 28th hospital day.
Acute Kidney Injury ; Administration, Intravenous ; Aged ; Alkalies ; Alkalosis ; Calcium Citrate ; Calcium* ; Creatinine ; Eating ; Enterocolitis, Pseudomembranous ; Fractures, Compression ; Furosemide ; Humans ; Hypercalcemia* ; Hyperparathyroidism ; Hyperparathyroidism, Primary ; Lethargy ; Osteoporosis ; Pneumonia, Aspiration ; Renal Insufficiency ; Renal Replacement Therapy ; Respiration, Artificial ; Sepsis ; Spine

OBJECTIVE: To compare the clinical outcomes following conservative treatment and arthroscopic repair in patients with a rotator cuff tear. METHODS: In this retrospective study, patients aged >50 years with a symptomatic rotator cuff tear were reviewed. The rotator cuff tendons were evaluated using ultrasonography, shoulder magnetic resonance imaging or MR arthrography, and the patients with either a high-grade partial-thickness or small-to-medium-sized (≤3 cm) full-thickness tear were included in this study. The primary outcome measures were a pain assessment score and range of motion (ROM) at 1-year follow-up. The secondary outcomes were the rate of tear progression or retear along with the rate of symptom aggravation after the treatments. RESULTS: A total of 357 patients were enrolled, including 183 patients that received conservative treatment and 174 patients who received an arthroscopic repair. The pain assessment score (p<0.001) and the ROM in forward flexion (p<0.001) were significantly improved in both groups. The ROM in internal rotation did not significantly change after conservative treatment and arthroscopic repair. The pain assessment score and ROM were not significantly different between the two groups. Retear was observed in 9.6% of patients who had an arthroscopic repair and tear progression was found in 6.7% of those who underwent conservative treatment. The proportion of aggravation for pain and ROM did not significantly differ between the two groups. CONCLUSION: The effectiveness of conservative treatment is not inferior to arthroscopic repair for patients >50 years old with a less than medium-sized rotator cuff tear in a 1-year follow-up period. Further study is warranted to find the optimal combination of conservative treatment for a symptomatic rotator cuff tear.
Arthrography ; Arthroscopy ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Observational Study* ; Outcome Assessment (Health Care) ; Pain Measurement ; Range of Motion, Articular ; Retrospective Studies* ; Rotator Cuff* ; Shoulder ; Tears* ; Tendon Injuries ; Tendons ; Treatment Outcome ; Ultrasonography

STUDY DESIGN: Prospective randomized noninferiority trial. PURPOSE: To evaluate whether the union rate of anterior cervical discectomy and fusion (ACDF) using a polyetheretherketone (PEEK) cage filled with a mixture of hydroxyapatite (HA) and demineralized bone matrix (DBM) is inferior to that of a mixture of beta-tricalcium phosphate (beta-TCP) and HA. OVERVIEW OF LITERATURE: There have been no clinical trials investigating the outcomes of a mixture of HA and DBM in a PEEK cage in ACDF. METHODS: Eighty-five eligible patients were randomly assigned to group B (n=43), in which a PEEK cage with a mixture of HA and DBM was used, or group C (n=42), in which a PEEK cage with a mixture of HA and beta-TCP was used. The primary study endpoint was the fusion rate, which was assessed with dynamic radiographs and computed tomography (CT) scans. Secondary endpoints included pain intensity using a visual analogue scale, functional outcome using a neck disability index score, laboratory tests of inflammatory profiles, and the infection rate. RESULTS: Seventy-seven patients (38 in group B and 39 in group C) were included in the final analysis. One year postoperatively, bone fusion was achieved in 87% of group B patients and 87% of group C patients on dynamic radiographs, and 87% of group B patients and 72% of group C patients on CT scans (p=1.00 and 0.16, respectively). There were also no between-groups differences with respect to the secondary endpoints. CONCLUSIONS: A HA/DBM mixture inside a PEEK cage can provide noninferior outcomes compared to a HA/TCP mixture in ACDF.
Bone Matrix* ; Diskectomy* ; Durapatite ; Humans ; Hydroxyapatites ; Neck ; Prospective Studies* ; Tomography, X-Ray Computed

We report an unusual case of adult minimal change nephrotic syndrome relapsed after 15-year of complete remission. In this case, the disease had occurred to the patient for the first time when he was 52 years old; relatively high age, and had been remitted with steroid therapy. After 15 years of complete remission, he visited our hospital with the symptoms of the generalized edema and the pitting edema of both lower extremities that occurred 15 days ago. Massive proteinuria(15, 865 mg/day) and hypoalbuminemia(1.7 g/dL) were detected. The pathologic evaluation of the biopsied specimen of the kidney showed the global sclerosis in 19% of glomeruli in light microscopic finding and the fusion of epithelial foot processes in electron microscopic finding. He was treated with pulse steroid therapy (methylprednisolone 500 mg/day iv for 3 days) and then, with oral prednisolone (60 mg/day). Generalized edema and proteinuria disappeared after 14 days of treatment, and there has been no relapse ever since. Adult-onset minimal change nephrotic syndrome relapses within 4 years after complete remission in 90 % of relapsed patients. The relapse after more than 5 years of complete remission, like this case, is very rare, especially in the case of late-onset disease. However, the possibility of relapse of the minimal change nephrotic syndrome after several years of its remission should be considered constantly and the long-term follow-up more than 10 years may be needed.
Adult ; Edema ; Follow-Up Studies ; Foot ; Humans ; Kidney ; Lower Extremity ; Middle Aged ; Nephrosis, Lipoid* ; Prednisolone ; Proteinuria ; Recurrence ; Sclerosis

PRK is presumed to be safe with a high success rate and few complications.However, since epithelial defects created by surgery disrupt corneal barrier function, infectious keratitis may occur.We experienced a case of bilateral infectious keratitis after PRK in a 32 years old woman who had complained of pain and blurred vision in both eyes.To our knowledge, no bilateral infectious keratitis after PRK has been reported in the literature. In our case, we presumed that infectious keratitis after PRK occurred due to therapeutic soft contact lenses, possibility of intraoperative contamination, physical stress or ultraviolet radiation.Although the causative organism was not identified on culture, clinical pattern of keratitis was similar to bacterial infection.The patient was treated with maximal topical antibiotics on both eyes and with amniotic membrane patching in the left eye.After proper management, the patient'suncorrected visual acuity had returned to 1.0/0.9 in Snellen chart. This case emphasizes the need for an informed consent for postoperative complications, careful preoperative examination, and proper management.
Adult ; Amnion ; Anti-Bacterial Agents ; Contact Lenses, Hydrophilic ; Female ; Humans ; Informed Consent ; Keratitis* ; Postoperative Complications ; Visual Acuity