Zirconia Phase Transformation,Metal Transfer,and Surface Roughness in Retrieved Ceramic Composite Femoral Heads in Total Hip Arthroplasty

Ceramic femoral heads have had promising results as a bearing surface in total hip arthroplasty. Our objective was to evaluate a series of retrieved alumina-zirconia composite ceramic femoral heads for evidence of the tetragonal to monoclinic zirconia phase transformation, metal transfer and articular surface roughness. Raman spectra showed evidence of the zirconia phase transformation in all retrieved specimens, with distinct monoclinic peaks at 183, 335, 383, and 479 cm^− 1. All components displayed metal transfer. An increase in the zirconia phase transformation was seen with increasing time in vivo. No correlation between extent of zirconia phase transformation and the surface roughness was found. These short-term results suggest that the use of an alumina-zirconia composite ceramic is a viable option for femoral heads in THA.     

Evaluation of the 3-Dimensional,Weight-Bearing Orientation of the Normal Adult Knee

The purpose of this study was to use 3-dimensional, weight-bearing images corrected for rotation to establish normative data of limb alignment and joint line orientation in asymptomatic, adult knees. One hundred adults (200 lower extremities) were recruited to receive weight-bearing, simultaneous biplanar imaging of both lower extremities. Multiple radiographic parameters were measured from 3D images, corrected for limb rotation. 70.0% of knees were in neutral, 19.5% in varus, and 10.5% in valgus overall alignment. Only 31 % of knees possessed both a neutral mechanical axis and the absence of joint line obliquity. There was substantial agreement between the 2D and 3D images for overall mechanical alignment (κ = 0.77), but only a moderate agreement for joint line obliquity (κ = 0.58). A substantial portion of asymptomatic adults possess either a varus or valgus mechanical alignment and joint line obliquity.     

Twist technique for removal of spinal extradural arachnoid cyst: technical note

Study design

We document a spinal extradual arachnoid cyst treated by twist technique. The cyst is tightly adherent to the neural tissue or the dura, and the communication stalk is little or short.

Objective

To demonstrate the effectiveness of twist technique of closure of the communication stalk for the removal of spinal extradural arachnoid cyst.

Summary of background data

The standard treatment for a spinal extradural arachnoid cyst is complete excision of the cyst, followed by obliteration of the communication stalk and repair of the dural defect. To our knowledge, twist technique of the communication stalk for removal of spinal extradural arachnoid cyst has not been reported.

Methods

A 44-year-old woman presented with a 10-year history of pain and dysesthesia, initially in the posterior neck region and extending gradually to the distal portion of the right upper extremity. Pain and dysesthesia were exaggerated when she was lying down and relieved when standing or walking. She was diagnosed with an extradural arachnid cyst ranging from spinal regions T1 to T3 using MRI. Computerized tomography myelography revealed a mass located posterior to the spinal cord. Pooling of contrast medium was observed in the lesion indicating communication with the subarachnoid space. Laminectomy of the T1–T3 region was performed, preserving the spinous processes and the facet joints. A short communication stalk was found at the proximal root sleeve of right T3. This stalk was closed using twist technique.

Results

The patient experienced marked reduction of pain and dysesthesia after surgery, and the headache and blurred vision completely disappeared. Five days after the operation, she was discharged home in good condition. Postoperative 1 year later, the patient had completely recovered and resumed her normal life.

Conclusions

Twist technique can be seen safe and effective as another surgical option for spinal extradural arachnoid cysts containing a short stalk and dense fibrous adhesion with the dura mater.     

Cilostazol suppresses β‐amyloid production by activating a disintegrin and metalloproteinase 10 via the upregulation of SIRT1‐coupled retinoic acid receptor‐β

The accumulation of plaques of β‐amyloid (Aβ) peptides, a hallmark of Alzheimer's disease, results from the sequential cleavage of amyloid precursor protein (APP) by activation of β‐ and γ‐secretases. However, the production of Aβ can be avoided by alternate cleavage of APP by α‐and γ‐secretases. We hypothesized that cilostazol attenuates Aβ production by increasing a disintegrin and metalloproteinase 10 (ADAM10)/α‐secretase activity via SIRT1‐coupled retinoic acid receptor‐β (RARβ) activation in N2a cells expressing human APP Swedish mutation (N2aSwe). To evoke endogenous Aβ overproduction, the culture medium was switched from medium containing 10% fetal bovine serum (FBS) to medium containing 1% FBS, and cells were cultured for 3～24 hr. After depletion of FBS in media, N2aSwe cells showed increased accumulations of full‐length APP (FL‐APP) and Aβ in a time‐dependent manner (3–24 hr) in association with decreased ADAM10 protein expression. When pretreated with cilostazol (10–30 μM), FL‐APP and Aβ levels were significantly reduced, and ADAM10 and α‐secretase activities were restored. Furthermore, the effect of cilostazol on ADAM10 expression was antagonized by pretreating Rp‐cAMPS and sirtinol and by SIRT1‐gene silencing. In the N2aSwe cells overexpressing the SIRT1 gene, ADAM10, and sAPPα levels were significantly elevated. In addition, like all‐trans retinoic acid, cilostazol enhanced the protein expressions of RARβ and ADAM10, and the cilostazol‐stimulated ADAM10 elevation was significantly attenuated by LE135 (a RARβ inhibitor), sirtinol, and RARβ‐gene silencing. In conclusion, cilostazol suppresses the accumulations of FL‐APP and Aβ by activating ADAM10 via the upregulation of SIRT1‐coupled RARβ. © 2014 Wiley Periodicals, Inc.     

Neuroprotection of posttreatment with risperidone,an atypical antipsychotic drug,in rat and gerbil models of ischemic stroke and the maintenance of antioxidants in a gerbil model of ischemic stroke

Risperidone, an atypical antipsychotic drug, has been discovered to have some beneficial effects beyond its original effectiveness. The present study examines the neuroprotective effects of risperidone against ischemic damage in the rat and gerbil induced by transient focal and global cerebral ischemia, respectively. The results showed that pre‐ and posttreatment with 4 mg/kg risperidone significantly protected against neuronal death from ischemic injury. Many NeuN‐immunoreactive neurons and a few F‐J B‐positive cells were found in the rat cerebral cortex and gerbil hippocampal CA1 region (CA1) in the risperidone‐treated ischemia groups compared with those in the vehicle‐treated ischemia group. In addition, treatment with risperidone markedly attenuated the activation of microglia in the gerbil CA1. On the other hand, we found that treatment with risperidone significantly maintained the antioxidants levels in the ischemic gerbil CA1. Immunoreactivities of superoxide dismutases 1 and 2, catalase, and glutathione peroxidase were maintained in the stratum pyramidale of the CA1; the antioxidants were very different from those in the vehicle‐treated ischemia groups. In brief, our present findings indicate that posttreatment as well as pretreatment with risperidone can protect neurons in the rat cerebral cortex and gerbils CA1 from transient cerebral ischemic injury and that the neuroprotective effect of risperidone may be related to attenuation of microglial activation as well as maintenance of antioxidants. © 2014 Wiley Periodicals, Inc.     

Lacosamide as an adjunctive therapy in pediatric patients with refractory focal epilepsy

Purpose: To evaluate the efficacy and safety of lacosamide in pediatric patients with refractory focal epilepsy. Methods: We reviewed retrospectively the medical records of children younger than 18 years of age treated at Seoul National University Bundang Hospital, in whom oral lacosamide was used as an adjunctive treatment for refractory focal epilepsy. Clinical information regarding the patients’ epilepsy and the outcome of lacosamide treatment was gathered and analyzed. Results: Twenty-one patients (16 boys, 5 girls) were included, with a median age of 13.9 (range, 1.2–17.9) years. The mean number of concomitant antiepileptic drugs was 3.0 (range, 1–6) and the mean duration of follow-up was 10.1 (range, 6.1–13.0) months. The mean maintenance dose of lacosamide was 5.4 (range, 1.4–9.8) mg/kg/day. Fourteen patients (67%) were responders; four of these were seizure free at the last follow-up. Seven patients (33%) were nonresponders: two of these presented with <50% seizure reduction and five showed no change in seizure frequency. Two patients (10%) discontinued oral lacosamide because of adverse events (aggressive behavior and depression). Mild transient treatment-related adverse events were observed in eight of the 21 patients (38%). Conclusions: Lacosamide represents a useful drug that is effective for a wide range of pediatric refractory focal epilepsy and is well tolerated.