In vivo implant fixation of carbon fiber‐reinforced PEEK hip prostheses in an ovine model

Carbon fiber‐reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough‐textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone‐cement and cement‐stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA‐coated CFR/PEEK implants, even under load‐bearing conditions. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 485–492, 2013     

Merits and Demerits of Operative Procedure to the Trachea in Patients with Differentiated Thyroid Cancer

Local radical thyroidectomy, including cervical lymph node dissection and combined circumferential resection of the trachea, has been performed over the past 20 years in 31 patients with differentiated cancer invading the trachea. The 5- and 10-year survival rates for these patients were 77.4% and 66.7%, respectively. In 19 of the 31 (61%) cases the recurrent nerve was resected because of direct cancer invasion. Bilateral recurrent nerve palsy occurred in 12 patients, 3 of whom were managed postoperatively using a T-shaped tube for preservation of the larynx. Hoarseness remained in 21 patients. In two patients with recurrent cancer invasion of the larynx, partial laryngectomy and hemilaryngectomy were performed, and reconstruction was done using ear cartilage without postoperative dyspnea or dysphagia. Parathyroid function is an important factor in regard to the quality of life of patients. In 22 patients at least one of the parathyroids was preserved. Postoperative calcium administration was necessary in 14 patients. Our long-term observations indicate that local radical thyroidectomy with combined resection of the trachea can serve as a useful treatment for advanced differentiated cancer invading the airway.     

Solid-pseudopapillary pancreatic tumor, mimicking submucosal tumor of the stomach: A case report

Solid-pseudopapillary tumors of the pancreas(SPTs) are comparatively rare and have low malignancy,with a predilection for young women.Diagnosis is difficult when a SPT develops in a boundary region with other organs.Here,we report a 42-year old woman with a SPT of the pancreas mimicking a submucosal tumor of the stomach on imaging.She was admitted to our hospital complaining of abdominal pain.We suspected a submucosal tumor of the stomach from the f indings of endoscopy,endoscopic ultrasonography and abdominal computed tomography.However,angiography showed that some of the tumor vessels arose from the pancreas.Intraoperative f indings revealed the tumor originated from the pancreas.Therefore,distal pancreatectomy was performed.The pathological diagnosis was SPT of the pancreas.     

Culture-expanded periosteal-derived cells exhibit osteochondrogenic potential in porous calcium phosphate ceramics in vivo.

Chick tibial periosteal cells were enzymatically disaggregated, introduced into cell culture, and subcultured. These subcultured cells were combined with porous calcium phosphate ceramics and implanted into a subcutaneous site in athymic mice as an immunocompatible host to test the in vivo osteochondrogenic potential of this composite graft. These cells eventually gave rise to bone tissue in the pores of ceramics at the heterotopic implantation sites. The process of bone formation occurred through two different mechanisms: Intramembranous bone formation occurred at the peripheral pores of ceramics early, and endochondral bone formation occurred in the central pores later. Cultured chick muscle fibroblasts of the same-aged donor as controls did not form bone or cartilage under identical conditions to those of cultured periosteal-derived cells. These results raise the possibility that composite graft of cultured periosteal-derived cells and porous ceramics can be clinically used as a bone graft substitute in situations requiring bone augmentation or regeneration.     

Application of support vector machine classifiers to preoperative risk stratification with myocardial perfusion scintigraphy

BACKGROUND: Myocardial perfusion single-photon emission computed tomography (SPECT) has been used for risk stratification before non-cardiac surgery. However, few authors have used mathematical models for evaluating the likelihood of perioperative cardiac events. METHODS AND RESULTS: This retrospective cohort study collected data of 1,351 patients referred for SPECT before non-cardiac surgery. We generated binary classifiers using support vector machine (SVM) and conventional linear models for predicting perioperative cardiac events. We used clinical and surgical risk, and SPECT findings as input data, and the occurrence of all and hard cardiac events as output data. The area under the receiver-operating characteristic curve (AUC) was calculated for assessing the prediction accuracy. The AUC values were 0.884 and 0.748 in the SVM and linear models, respectively in predicting all cardiac events with clinical and surgical risk, and SPECT variables. The values were 0.861 (SVM) and 0.677 (linear) when not using SPECT data as input. In hard events, the AUC values were 0.892 (SVM) and 0.864 (linear) with SPECT, and 0.867 (SVM) and 0.768 (linear) without SPECT. CONCLUSION: The SVM was superior to the linear model in risk stratification. We also found an incremental prognostic value of SPECT results over information about clinical and surgical risk.     

Detection of serum antibody by the antimitogen assay against streptococcal erythrogenic toxins. Age distribution in children and the relation to Kawasaki disease

We describe a new method to measure human serum antibody against streptococcal erythrogenic toxins that uses inhibition of lymphocyte mitogenicity of the toxins as the indicator. Sera from 53% of 53 Kawasaki disease patients contained specific inhibitory activity against A toxin, whereas only 15% had serum inhibitory activity against B toxin. The specific anti-A toxin serum inhibitor was found in 10% of 118 age-matched control patients suffering from various infections and allergic diseases (p = 0.001, compared to Kawasaki disease patients). Serum inhibitory activity was detected in a small number of patients with beta-hemolytic streptococcal infection (3/19) and in none of the age-matched healthy children (0/17). However, four of seven cord blood sera samples and five of 13 sera samples from healthy neonates contained the inhibitor, a result suggesting passive transfer from mothers. Most of the antimitogen-positive sera were also positive by ELISA of IgG antibody against A toxin, and IgG fractions of the positive sera remained positive in both assays. Thus, it is possible that the specific serum inhibitor detected by the antimitogen assay represents anti-A toxin antibody. The role of toxin-producing bacteria in the pathogenesis of Kawasaki disease remains to be investigated.     

Cell-cycle-dependent invasion in vitro by rat ascites hepatoma cells

The relationship between cell cycle and experimental metastasis of tumor cells in vivo has been investigated, but it remains to be elucidated which step of metastasis, or whether tumor-cell invasion in particular, depends on cell cycle. We previously reported an in vitro cell-monolayer invasion (transcellular migration) assay system, in which the invasive capacity of tumor cells is measured by counting tumor cells penetrating beneath a cultured mesothelial cell monolayer after tumor-cell seeding. Using our invasion assay system, the relationship between invasive capacity and cell-cycle distribution of MMI cells, a highly invasive clone of rat ascites hepatoma AH130, was investigated. Invasive capacity of aphidicolin- or hydroxyurea-synchronized tumor cells enriched in G₁/S—early S-phase cells was about 2 to 6 times higher than that of asynchronous cells. According to time-course experiments to examine the relationship between invasive capacity and the size of fraction of cells in each phase after release from an aphidicolin or a nocodazole block, it was suggested that MMI cells are most invasive in G₁/S-S phase. Phagokinetic assay using colloidal gold particles showed that one possible reason for the enhanced invasiveness might be the increased cell motility in such phases, as suggested by the in vitro invasion assay.     

Rapid regrowth of solitary subependymal giant cell astrocytoma--case report

A 48-year-old female presented with a subependymal giant cell astrocytoma (SEGA) without tuberous sclerosis manifesting as memory and mental disturbance. Magnetic resonance imaging showed a huge mass which was well-demarcated and extended from the anterior horn of the right lateral ventricle to the septal area on the right side. Surgery was performed with partial removal of the tumor. The histological diagnosis was typical SEGA. One year postoperatively, follow-up magnetic resonance imaging revealed marked regrowth of the tumor. Total resection of the tumor was performed. Microscopic and immunohistochemical studies could not identify the cause of the rapid regrowth. SEGA can regrow rapidly after partial removal of the tumor.     

Evidence for the possible involvement of Ca<Superscript>2+</Superscript> entry blockade in the relaxation by class I antiarrhythmic drugs in the isolated pig coronary smooth muscle

Effects of several Na+ channel blockers (i.e., class I antiarrhythmic agents), procainamide, quinidine, lidocaine, mexiletine, propafenone, were investigated in the isolated endothelium-denuded pig coronary artery focusing on the possible involvement of the blockade of Ca2+ channels and/or opening of K+ channels in the relaxant responses.All drugs except procainamide induced a concentration-dependent full relaxation of the coronary artery precontracted with high-KCl (30 mM, 80 mM). Inhibitions by procainamide of both high-KCl-induced contractions were less than 50% even at a concentration of 3 x 10(-2) M. Both high-KCl contractions were diminished by an L-type Ca2+ channel blocker, diltiazem, in a concentration-dependent manner. In contrast, cromakalim failed to inhibit 80 mM KCl-induced contraction. Tetrodotoxin (3 x 10(-5) M) did not affect the relaxant actions of the tested class I antiarrhythmic agents in high-KCl (80 mM)- or prostaglandin F2alpha-contracted muscle. The inhibitions by these class I antiarrhythmic agents of high-KCl-induced contraction were significantly attenuated when extracellular CaCl2 was increased from 2 mM to 20 mM. Furthermore, procainamide, quinidine, lidocaine, mexiletine as well as diltiazem decreased both cytoplasmic Ca2+ level ([Ca2+](cyt)) and muscle tension elevated by high-KCl in fura-2-loaded coronary preparations.These findings suggest that blockade of voltage-gated Ca2+ channels is involved in the relaxing action of these class I antiarrhythmic drugs in pig coronary artery. Blockade of Na+ channel and/or opening of K+ channels does not seem to play the principal role in the mechanism by which these antiarrhythmic drugs relax coronary artery.