Risk Factor Analysis of Facet Fusion Following Cervical Lateral Mass Screw Fixation with a Minimum 1-Year Follow-up: Assessment of Maximal Insertional Screw Torque and Incidence of Loosening

Posterior stabilization is a common surgical procedure, which aims for rigid stabilization by facet fusion. Facet non-union has a potential risk of the screw loosening and malalignment. Although some authors have reported the influencing factors about screw loosening in the lumbar spine, there are few reports about the risk factor contributing to the facet non-union in the cervical spine. In all, 22 patients (78 facets and 122 screws) with degenerative cervical kyphosis or spondylolisthesis who underwent decompression and lateral mass screw (LMS) fixation were analyzed. Age, gender, smoking, bone mineral density (BMD), the degree of facet decortication with bone packing, and screw loosening were investigated as risk factors contributing to the facet non-union at each segmental fused level. Facet fusion rate was 85.9% (67/78 facets) and the incidence of loosening was 4.9% (6/122 screws, 4 patients). Insufficient facet decortication with bone packing is a significant risk factor of facet non-union (p <0.05, odds ratio: 26.5). All six loosened screws were associated with bony non-union of the facet and were located in the uppermost or lowermost vertebrae. Comparing loosened screws and stable screws, the average maximal insertional screw torque (MIT) was 9.8 cNm and 39.5 cNm, respectively (p <0.05). Additionally, the length of the stable screws was significantly longer versus the loosened screws (p <0.05). Lower MIT and shorter screw length located near the ends of the lateral mass may predict loosening, which can lead to facet non-union. Sufficient facet decortication with bone packing is one of the important factors contributing to the facet fusion.     

Cutaneous ultrastructural diagnosis of ceroid-lipofuscinosis

A skin biopsy from a 6-year-old girl was examined by electron microscopy and the diagnosis of ceroid-lipofuscinosis (CL) was confirmed. This has not been reported in the dermatology literature, because of the absence of specific skin manifestations. However, as we have shown, various cells of skin, including fibroblasts, Schwann cells, eccrine serous cells, endothelial cells and smooth muscle cells, accumulated characteristic substances to produce the finger print pattern (FPP) or the curvilinear profile (CLP) which are thought to be diagnostic for CL. Cutaneous ultrastructural research in such cases is important as asymptornatic skin disorders may exist in other congenital storage diseases.     

Deficiency of Testosterone Associates with the Substrate of Atrial Fibrillation in the Rat Model

Background: Since the prevalence of atrial fibrillation (AF) increases progressively with aging, especially in men, we hypothesized that testosterone might affect the occurrence of AF.
Methods and Results: We examined the electrophysiological properties of the atria in isolated-perfused hearts of sham-operated male (SM), female (SF), orchiectomized male with and without administration of testosterone (ORCH-T and ORCH), and ovariectomized female (OVX) Sprague-Dawley rats. An electrophysiological study revealed that repetitive atrial responses induced by electrical stimuli significantly increased in ORCH rats without changes in other electrophysiological properties and were abolished by administration of testosterone. To investigate the underlying mechanisms, we evaluated the expression level of calcium-handling proteins. In ORCH rats, the immunoreactive protein level of ryanodine receptor type 2 (RyR2) and sodium–calcium exchanger significantly increased as compared with SM and ORCH-T rats without alterations in the level of FK506-binding protein (FKBP12.6), sarcoendoplasmic reticulum Ca-ATPase, and phospholamban. Immunoprecipitation analysis demonstrated decreased binding of FKBP12.6 to RyR2 in ORCH rats, which was prevented by testosterone. In contrast, the expression levels of these proteins showed no significant differences between SF and OVX rats.
Conclusion: Deficiency of testosterone was arrhythmogenic in rat atria possibly through less binding of FKBP12.6 to RyR2, which could induce feasible calcium leakage from the sarcoendoplasmic reticulum. These results would explain, at least in part, the increase in the prevalence of AF in accordance with the decline of testosterone particularly in elderly men.     

Role of vagotony in sinus node dysfunction in children with symptomatic congenital long QT syndrome

The present study examined chronotropic dysfunction and the role of vagotony in congenital long QT syndrome, sinus node function and the effects of parasympathetic blockade. Six patients with congenital long QT syndrome were studied. The four males and two females, aged 1–15 years, had episodes of syncope and malignant ventricular arrhythmias. Congenital long QT syndrome was defined as a corrected QT interval greater than 0.45 s, T wave alternans and the age at diagnosis. The sinus heart rate measured from a 24 h electrocardiograph was abnormally low (< 50 min) in three patients (1, 4 and 5 years old) and did not increase sufficiently with the administration of atropine in five of the six patients with congenital long QT syndrome. From intracardiac electrophysiological studies, the corrected sinus node recovery time was prolonged in three patients and the total sinoatrial conduction time was prolonged in two patients. In most patients who had an abnormally long sinoatrial conduction time and corrected sinus node recovery time, these values returned to normal following atropine administration. In one patient, the corrected sinus node recovery time was prolonged paradoxically by atropine. Sinus node dysfunction in congenital long QT syndrome was affected by vagotony associated with a right sympathetic nerve system abnormality.     

Ureteral obstruction due to retroperitoneal fibrosis secondary to a solitary internal iliac aneurysm

We report a case of ureteral obstruction due to retroperitoneal fibrosis secondary to a solitary left internal iliac aneurysm. It has been reported that as a cause of ureteral obstruction, an internal iliac aneurysm without aortic and/or common iliac aneurysms is very rare. In the present case, magnetic resonance imaging was a useful modality to diagnose retroperitoneal fibrosis secondary to an internal iliac aneurysm as a direct cause of ureteral obstruction.     

An α-adrenoceptor-mediated mechanism of hypoactivity induced by β-amyrin palmitate

Abstract— Inhibitory effects of β-amyrin palmitate in locomotor activity of mice were studied by combining this compound with α-adrenergic agonists or antagonists and a dopaminergic agonist. β-Amyrin palmitate (2·5, 5·0 and 10·0 mg kg^?1, i.p.) decreased locomotor activity of mice in a dose-dependent manner. It enhanced hypoactivity of mice treated with clonidine (0·025 mg kg^?1, i.p.) and antagonized hyperactivity produced by phenylephrine (40 μg, i.c.v.). The inhibitory action of β-amyrin palmitate was not affected by yohimbine (1·5 mg kg^?1, i.p.), but was potentiated by prazosin (0·75 mg kg^?1, i.p.). When combined with a dopaminergic agonist, apomorphine (2·0 mg kg^?1, i.p.), β-amyrin palmitate (5·0 and 10·0 mg kg^?1, i.p.) did not affect locomotor stimulation produced by apomorphine. These results suggest that β-amyrin palmitate might inhibit α₁-adrenoceptors.     

Polysomnography and body temperature changes by phototherapy in a delayed sleep phase syndrome case

Abstract We examined polysomnography (PSG) and body temperature in a patient with delayed sleep phase syndrome who responded to phototherapy. The patient was a 31-year-old woman whose condition had slightly improved by a vitamin B₁₂ administration. Phototherapy was administered to her in combination with the vitamin B₁₂ medication, and this combined treatment successfully advanced her delayed sleep phase. On PSG, the regimen showed shortened sleep latency, decreased total sleep time and stages 1 and 2 sleep, and increased slow wave sleep. Phototherapy also improved temporal distribution of delta half-waves (0.5-2.0 Hz, 31 µV) as well as phase relationship between sleep and body temperature.     

Effects of ultraviolet B irradiation on cell–cell interaction; implication of morphological changes and actin filaments in irradiated cells

We studied the effects of ultraviolet B (UV-B) irradiation on cell–cell interactions using mouse lymphoma RMA cells and T cell hybridoma HTB-176.10 cells. RMA cells act as stimulators by presenting H-2K^b surface antigens to HTB-176.10 cells, inducing IL-2 production in HTB-176.10 cells. Irradiating RMA cells with 1000 J/m² UV-B suppressed cell cluster formation between RMA and HTB-176.10 cells and reduced the level of IL-2 production in HTB-176.10 cells, although H-2K^b surface antigens of RMA cells were still expressed. Electron microscopic observations of irradiated RMA cells revealed that UV-B irradiation damaged cell structures, resulting in the disappearance of microvilli on the cell surface, destruction of mitochondria, vacuolation of cytoplasm and swelling of the perinuclear cisterna space. We found that these alterations were accompanied by polymerization of filamentous actin quantified by flow cytometry after NBD-phallacidin staining. Our results suggest that a target of UV-B-induced alterations is actin filaments, which support the cell morphology as the cytoskeleton, and that modification of filamentous actin inhibits interaction between RMA and HTB-176.10 cells. This underlying mechanism may account for the impaired interaction between antigen-presenting cells and T cells after transfusion with UV-B-irradiated allogeneic blood components.