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Purpose:The preservation technique of the piriformis tendon during the posterolateral approach in total hip arthroplasty (THA) is reportedly superior to the reattachment technique in terms of dislocation. However, the long-term effects of preservation of the piriformis tendon during THA remain unknown. In this study, we evaluated the contiguity of the piriformis/conjoined tendon and atrophy of the piriformis/internal obturator muscle during a long-term postoperative follow-up using magnetic resonance imaging (MRI).Methods:We retrospectively evaluated 48 patients with available MRI. The 48 patients were classified into a P group ( n = 29), in which the piriformis tendon was preserved, and an R group ( n = 19), in which the piriformis was reattached after sectioning. The mean follow-up duration was 45.9 months. The contiguity of the piriformis/conjoined tendon and atrophy of the piriformis/internal obturator muscle were evaluated in all patients.Results:The piriformis tendon remained attached to the greater trochanter in all P-group patients and 68.4% of R-group patients. The mean piriformis muscle atrophy ratios were 15.9% ± 21.1% in the P group and 41.6% ± 19.1% in the R group ( p < 0.001). The conjoined tendon repair remained intact in 72.4% of P-group patients and 36.8% of R-group patients ( p < 0.05). The mean internal obturator muscle atrophy ratio was 31.4% ± 26.2% in the P group and 50.4% ± 19.1% in the R group ( p < 0.05). No postoperative pulmonary embolism, wound infection, deep infection, or hip dislocation occurred.Conclusions:In our study, we suggest that the preservation technique of the piriformis tendon is superior to the reattachment technique in terms of contiguity and muscle atrophy.

The epidemiology of patients with traumatic brain injury (TBI) has changed dramatically over recent decades as a result of rapid advances in aging societies. We assessed the influence of age on outcomes of patients with TBI and sought to identify prognostic factors for in-hospital mortality of TBI among elderly patients.Using a nationwide database, we analyzed data from 5651 patients with TBI. Univariate analysis was conducted to compare patient demographics, neurologic status on admission, radiologic findings, systemic complication rates, length of hospital stay, in-hospital mortality, and home discharge rates between elderly and nonelderly groups. Multivariable analysis was conducted to determine prognostic factors for in-hospital mortality among elderly patients.Overall in-hospital mortality was significantly higher in elderly patients (12.8% vs. 19.3%; P0.001). In-hospital mortality of elderly patients with mild TBI increased significantly at7 days after admission, whereas that of elderly patients with moderate or severe TBI was significantly higher immediately after admission. Age (odds ratio [OR], 1.62; P = 0.024), male sex (OR, 1.30; P = 0.004), Japan Coma Scale score on admission (OR, 5.95, P0.001), and incidence of acute subdural hematoma (OR, 1.89; P0.001) were associated with in-hospital mortality in elderly patients with TBI.Elderly patients with TBI showed significantly higher in-hospital mortality. Delayed increases in in-hospital mortality were observed among elderly patients with mild TBI. Level of consciousness on admission was the strongest predictor of in-hospital mortality among elderly patients.

Peri-acetabular osteotomy, especially curved peri-acetabular osteotomy, is an effective surgical procedure for re-orientating the acetabulum. However, there have been few reports on this procedure in teenagers. The purpose of this study was to investigate the treatment outcomes of curved peri-acetabular osteotomy in teenagers. We retrospectively reviewed 33 hips in 27 teenage patients with acetabular dysplasia who underwent curved peri-acetabular osteotomy between 1995 and 2012. The mean age was 17.0 years (range, 14–19 years). The mean follow-up duration at the most recent physical examination was 33.3 months (range, 24–96 months). All hips were evaluated in terms of the Harris hip score, radiographic measurements, and complications. The mean Harris hip score improved from 80.1 points pre-operatively to 95.4 points post-operatively (p

We retrospectively analyzed 83 metal-on-metal total hip arthroplasties in 74 patients. Ultrasonography and magnetic resonance imaging (MRI) of each hip were performed to detect abnormal patterns and pseudotumors. We examined the reliability of ultrasonography for detecting pseudotumors in comparison with MRI. We also compared the acetabular component inclination between patients with and without pseudotumors. The mean positive and negative predictive values for pseudotumor detection by ultrasonography were 65% and 91%, respectively. The mean positive and negative likelihood ratios were 5.78 and 0.32, respectively. There was no clear association between pseudotumor presence and acetabular component inclination. We concluded that ultrasonography is a suitable technique to screen for the presence of pseudotumors. We also need to distinguish between bearing-related and taper junction corrosion-related complications.

Several radiological methods of measuring anteversion of the acetabular component after total hip replacement (THR) have been described. These studies used different definitions and reference planes to compare methods, allowing for misinterpretation of the results. We compared the reliability and accuracy of five current methods using plain radiographs (those of Lewinnek, Widmer, Liaw, Pradhan, and Woo and Morrey) with CT measurements, using the same definition and reference plane. We retrospectively studied the plain radiographs and CT scans in 84 hips of 84 patients who underwent primary THR. Intra- and inter-observer reliability were high for the measurement of inclination and anteversion with all methods on plain radiographs and CT scans. The measurements of inclination on plain radiographs were similar to the measurements using CT (p = 0.043). The mean difference between CT measurements was 0.6° (-5.9° to 6.8°). Measurements using Widmer’s method were the most similar to those using CT (p = 0.088), with a mean difference between CT measurements of -0.9° (-10.4° to 9.1°), whereas the other four methods differed significantly from those using CT (p < 0.001). This study has shown that Widmer’s method is the best for evaluating the anteversion of the acetabular component on plain radiographs. Cite this article: Bone Joint J 2014; 96-B:597–603.

In recent years, fuel consumption of vehicles has been remarkably improved by some cutting edge technologies (e.g., hybrid electric vehicles, non-idling systems). In-vehicle equipment is also required to improve efficiency. The vane pumps used to control power steering and transmissions must demonstrate maximum performance, even under high temperature conditions and with rich gases contained in hydraulic oil. Precise recognition of the dynamics of pump inner flow can help in the design and development of vane pumps. In this study, the 3-dimensional CFD is adopted to analyze the characteristics of inner flow dynamics of vane pumps. Since the gases contained in hydraulic oil influence the characteristics of vane pumps, the two-phase flow model with cavitation is assumed in particular. First, this CFD was verified by comparison with experimental results which were carried out at higher rotational speeds and with oil containing a high level of gas; the results showed the error of the suction flow rate could be as little as 5% or less. Internal pressure in the vane chambers was then studied to identify the relationship between the cavitation model and the contained gas ratio of the oil. The simulation results further clarified that the gas clouds deformed by pump rotation could restrict the flow of the suction ports.

Introduction Various methods have been described for measuring acetabular component anteversion. However, accurate measurement of anteversion is difficult. We herein propose a new method using cross-table lateral (CL) radiography performed with the contralateral hip flexed to 45° (45° flexed CL radiography). The main purpose of this study was to evaluate the reliability and validity of this new method. Methods The study group included 93 patients who underwent total hip arthroplasty (THA). All hips were evaluated with computed tomography (CT) and both standard and 45° flexed CL radiographs to measure acetabular component anteversion the week after THA. The intraobserver and interobserver reliability of each measurement was assessed. Plain radiography measurements were compared with reference CT measurements to evaluate their validity. Results All measurements had excellent intraobserver and interobserver reliability, and plain radiography measurements correlated well with CT measurements. The mean measurements were 21.9° (3°-39°) with CT, 24.9° (7°-47°; pDiscussion The anteversion values measured with our new method were closer to the CT values used as a reference standard than those with standard CL radiographs. Our new method appears to be reliable and valid for measuring acetabular component anteversion.

Background Although there were many clinical studies of highly cross-linked polyethylene (XLPE) wear among different femoral head diameters, few referred to thickness of XLPE in case larger femoral heads were used because smaller sockets were frequently used for Asian population. Methods This prospective study included 240 hips that underwent primary total hip arthroplasty using XLPE combined with 26-mm (group S) or 32-mm (group L) cobalt–chromium head with maximum follow-up of 10 years. We measured 3-dimensional (3-D) linear penetration rate of XLPE among same implant design groups except head diameter and estimated the validity of thinner XLPE. Results Our study demonstrated comparable 3-D linear penetration rates, which were 0.06 ± 0.07 mm/y for group S and 0.03 ± 0.02 mm/y for group L at 10 years after surgery and penetration rates seemed to be almost constant with no significant difference after 3 years. Minimum liner thickness (5.3 mm for 48-mm socket in combination with 32-mm femoral head) and the second thinnest XLPE (6.3 mm in case of socket from 50 mm to 54 mm combined with 32-mm femoral head) was distributed in 25% and 72% with group L, respectively, and there were no significant differences in penetration rates between 5.3-mm– and 6.3-mm–thickness groups. Conclusion Our study suggested that whether to select 26- or 32-mm diameters of femoral head does not affect XLPE wear in combination with this type of articulation.

Medial displacement of the femoral head reduces the force transmitted across the hip joint. Since 2005, we have performed a modified Ganz's osteotomy with curved periacetabular osteotomy (CPO) to obtain medialization of the femoral head. The modification involves cutting of the pubis at 30 degrees to the horizontal line. Here, we examined whether this modified CPO procedure medialized the femoral head more than the conventional CPO procedure.69 patients (mean age 37 years, 72 hips) treated with the modified CPO procedure (the M group) were compared with 68 patients (mean age 38 years, 72 hips) previously treated with conventional CPO (the C group). All patients were operated because of dysplastic hips. We used radiographic measurements from anteroposterior radiographs. The magnitude of the resultant hip force normalized with respect to the body weight (R/WB) and hip contact joint stress (Pmax/ WB) was calculated in all cases.The average lateral center-edge (CE) angle, acetabular roof obliquity (ARO), and acetabulum-head index (AHI) improved in both groups. The CE angle, ARO, and AHI were similar in the 2 groups before and after surgery. Medialization of the femoral head was larger in the M group than in the C group (p0.001). The average value of the resultant hip force decreased from 3.2 to 2.9 in the M group and remained unchanged, at 3.1, in the C group. In addition, the average value of the peak contact stress decreased more in the M group (from 9.4 kPa/N to 3.4 kPa/N) than in the C group (from 9.1 kPa/N to 4.3 kPa/N).In dysplastic hips, the modified CPO reduces the contact hip stress more than the conventional CPO because of better medialization of the femoral head.

We have performed carotid artery stenting (CAS) for 327 patients with ICA stenosis in our institutes using various embolic protection devices since 1997. After establishment of embolic protection methods in 1999, we have performed CAS for 114 asymptomatic carotid stenosis of more than 60%, according to the criteria of ACAS trial. In this paper, we report our initial results (perioperative complication, morbidity/mortality at 30 days after CAS, changes in stenosis ratio), rate of re-stenosis, and midterm results in cases followed more than 3 years after CAS. The mean preoperative stenosis ratio, 75.6%, remarkably decreased to 5.6% after CAS. The morbidity/motality rate at 30 days after CAS was 0.8% (1/114 cases). In 22 cases, followed up more than 3 years after CAS, no ipsilateral ischemic stroke was encountered. CAS for asymptomatic carotid stenosis is an effective and safe treatment to alleviate stenosis and prevent future ischemic stroke as well as carotid endarterectomy (CEA). Randomized controlled trials, based on the natural history of carotid stenosis, are needed in the near future to establish the indication of CAS for asymptomatic carotid stenosis.

The Bernese periacetabular osteotomy has a considerable rate of postoperative complications such as reflex sympathetic dystrophy, motor nerve palsy, heterotopic ossification, and delayed union of the ilium, which are assumed to be caused by extensive exposure or asphericity of the osteotomy surfaces. To address these issues, we developed the curved periacetabular osteotomy, a modification of the Bernese periacetabular osteotomy which limits dissection, prevents the outside of the ilium from being exposed, and produces osteotomy surfaces with the same curvature. Curved periacetabular osteotomies were done on 128 hips in 118 patients whose average age at the time of surgery was 35.2 years (range, 16-59 years). The average followup was 46 months (range, 24-99 months). The average center-edge angles were 4 degrees (range, -15 degrees -5 degrees ) preoperatively and 35 degrees (20 degrees -55 degrees ) postoperatively, and union of the iliac osteotomy was achieved in all hips. We experienced three asymptomatic pubic nonunions. Dysesthesias occurred in 27 patients along the lateral femoral cutaneous nerve and symptoms resolved in 23 patients within 1 year. The average Harris hip score improved from 72 to 93 points. There were no major complications such as sciatic nerve palsy, abductor dysfunction, or heterotopic ossification.Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

We have performed CAS for 239 patients with ICA stenosis in our institute using various protection devices since 1997. In this paper, we report our initial results (perioperative complication, morbidity/mortality 30 days after the procedure, change of stenosis ratio), rate of re-stenosis, and midterm results in the cases more than 3 years after CAS. The mean preoperative stenosis ratio, 79.6%, remarkably decreased to 6.2% after CAS. The morbidity/mortality rate at 30 days after CAS was 2.1% (5/239 cases). Five of 179 cases showed restenosis 6 months after CAS (3.2%). In 4 of these cases, in-stent PTA was performed. None of the cases showed new neurological deficits. In 62 cases, followed up more than 3 years after CAS, no ipsilateral ischemic stroke was encountered. Carotid artery stenting (CAS) for internal carotid artery (ICA) stenosis is an effective and safe treatment to alleviate stenosis and prevent future ischemic stroke as well as carotid endarterectomy (CEA). However, it is necessary to learn several technical methods and optional procedures for successful CAS in all carotid stenoses.

Ipsilateral distal femoral fracture after postoperative femoral neck fracture is a rare complication and treatment is often difficult. We treated three cases in which retrograde supracondylar intramedullary nails were used for internal fixation. The patients consisted of three females with ages ranging from 75 to 89. Two patients underwent hemiarthroplasty and another underwent Gamma nailing. According to AO classification, they were classified into A1 (2 cases) and C1 (1 case), respectively. All patients tended to fall down easily after postoperative femoral neck fracture.Consequently all fractures healed within four months. The average knee range of motion was —10 to 93 degrees. Clinical results were evaluated according to Neer's criteria. All cases were ranked as unsatisfactory. In generally, walking ability tended to deteriorate because multiple fractures occurred ipsilatelly. One case developed secondary femoral fracture at the mid shaft postoperatively, because of jamming between the distal tip of the cement and proximal tip of the intramedullay nail.Use of retrograde supracondylar intramedullary nail is effective for this type of fracture, but we have to be careful about the length of the intramedullary nail before surgical planning. As rigid fixation is difficult for the osteoporotic bone, post operative treatment is also important.

Recently, embolization using the Guglielmi detachable coil (GDC) has been performed as an alternative of direct surgery for cerebral aneurysms. We report clinical results and selection of treatment for cerebral aneurysms after introduction of GDC embolization at Wakayama Medical University and related hospitals. From 1997 to December 2001, 895 patients with intracranial aneurysms were treated either by direct surgery (n=798) or by GDC embolization (n=97). In 239 patients with unruptured aneurysms, 194 patients (81%) underwent direct surgery, while 45 patients (19%) had GDC embolization. In 656 patients with ruptured aneurysms, 604 cases (92%) were treated by direct surgery and 12 cases (8%), by GDC embolization. GDC embolization tended to be selected for paraclinoid IC or posterior fossa aneurysms, especially BA top, BA trunk and VA dissecting aneurysms. Vasospasm after SAH was statistically less in the embolization group than in the surgical group. In unruptured aneurysm series, morbidity and mortality rate of direct surgery was 5.7% and 0.5%, respectively, while those of GDC embolization was 4.4% and 0%, respectively. These clinical outcomes seemed to be almost the same as the previously published data by other neurosurgeons and interventional neuroradiologists. Therefore, our treatment selection and procedures are likely to be appropriate, especially in the unruptured group, after introduction of GDC embolization.

Purpose We performed curved periacetabular osteotomy, a modification of the Bernese periacetabular osteotomy, to treat hip dysplasia. The purpose of our study was to compare the biomechanical stability of acetabular fragments fixed in place with 3 titanium screws, or with 2 or 3 bioabsorbable screws composed of particulate resorbable uncalcined hydroxyapatite (HA) and poly-L-lactic acid (PLLA) termed HA/PLLA screws. Methods Curved periacetabular osteotomy was performed on 24 composite model hemipelves. Three groups of 8 specimens were affixed with 1) 3 titanium screws, 2) 2 HA/PLLA screws, or 3) 3 HA/PLLA screws. After fixation, the hemipelves were biomechanically attested with simulated push-off phase of the gait cycle using a servohydraulic material testing system. Results The average failure loads were not significantly different among the3 groups tested. However, the group repaired with 3 HA/PLLA screws showed significantly greater stiffness than the other groups. Conclusions All 3 fixation methods provided sufficient stability to allow for early partial weight-bearing after surgery. The use of 3 HA/PLLA screws provided significantly greater stiffness for acetabular fragment fixation.

Periacetabular osteotomy has been established as an effective treatment for osteoarthritis caused by developmental dysplasia of the hip. Medialisation of the femoral head during periacetabular osteotomy is crucial for providing significant reduction in joint contact stress. The purpose of this study was to evaluate effective procedures for medialisation of the femoral head during periacetabular osteotomy using three-dimensional computed tomography (3DCT).Thirty hips in 30 patients with hip dysplasia underwent both radiographic and 3DCT scans before and after surgery. The direction of the rotation of the acetabular fragment and movement of the femoral head were evaluated to analyse which parameters contributed to medialisation of the femoral head.Anterior coverage of the acetabular fragment and internal rotation in the axial plane contributed to both medialisation of the femoral head and anteversion of the retroverted acetabulum.This study demonstrated that re-orientation of the acetabulum was spatially confirmed by the method using 3DCT images.

Rosenberg devised a method to use Endobuttons (Acufex Microsurgical Inc. Mansfield, MA) for femoral fixation in ACL reconstruction.80 cases underwent arthroscopic anterior cruciate ligament (ACL) reconstruction using the Endobuttons from April 1997. There were 41 males and 39 females, whose ages ranged from 15 to 50 years (average 24.6 years). Our substitute was bone-patellar tendon-bone autogenous. Artificial ligament was anchored at the tibial side with a post screw.Based on these experiences, we reviewed the demerits of this procedure. The clinical results showed that the Endobutton, used for ACL endoscopic fixation, flips outside the extensor mechanism or vastus lateralis rather than flipping directly outside the lateral femoral cortex.We also found out one case in which the Endobutton dragged into the femoral tunnel during X-rays after operation.The purpose of this study was to estimate the cause of the demerits and improve the method.

An oil hydraulic pilot relief valve has been empirically investigated to fully understand its static performance. Constriction components which dominate the flow in the valves have been individually examined in detail, revealing that the static relation between the pressure drop, flow rate and opening area for a constriction can be represented, not by the traditional hydraulic orifice equation which has always been used for the purpose but by a new one including an additional pressure loss proportional to the flow rate and the fluid viscosity and inversely proportional to the square of the opening area. The new characteristic equation has proved to consistently predict the experimental findings in which the rise in oil temperature results in an increase in the piston displacement, but causes little changes as regards regulated pressure. It has also turned out that, contrary to conventional preconception, the fluid force exerted on a poppet is negligible. On the other hand, that regarding a piston can be influential and works to increase the pilot flow.

To investigate the biochemical mechanism responsible for NO-induced neurotoxicity, the effect of sodium nitroprusside(SNP), a NO-generating agent, on PC12 cells was studied. The cell density was dose-dependently inhibited by SNP. Neuronally differentiated PC12 cells showed a higher resistance to SNP than the undifferentiated cells. The inhibitory effect was enhanced by 8-Br-cGMP, and reduced by methylene blue. However, 8-Br-cGMP alone had no significant cytotoxicity. SNP also inhibited [3H]-thymidine incorporation into the cells in a dose-dependent manner. The dose response curves for reducing cell density and for inhibiting thymidine incorporation; were found to be virtually superimposable. These results suggested that cytotoxieity elicited by NO seemed to be due to inhibition of DNA synthesis in PC12 cells.

Noise generation during decompressing hydrogen in fuel cell vehicles is an issue requiring technological solution. This paper studies noise reducing effect and the flow characteristic of radial slits installed in a pressure reducing valve. Simulation is carried out to estimate the pressure–flow characteristic of the radial slit as a noise reducing mean. The simulation indicates a decrease of Reynolds number in the downstream-side of the radial slits structure, which causes noise reduction. Moreover, we proposed installing radial slits to the downstream of a conventional valve. Noise reduction by this new design was verified with a series of experiments. As a result, the valve with radial slits has a noise reduction effect of about 12.1 dB (A) compared with the conventional valve.

While ionizing radiation (Ir) instantaneously causes the formation of water radiolysis products that contain some reactive oxygen species (ROS), ROS are also suggested to be released from biological sources in irradiated cells. It is now becoming clear that these secondarily generated ROS after Ir have a variety of biological roles. Although mitochondria are assumed to be responsible for this Ir-induced ROS production, it remains to be elucidated how Ir triggers it. Therefore, we conducted this study to decipher the mechanism of Ir-induced mitochondrial ROS production. In human lung carcinoma A549 cells, Ir (10 Gy of X-rays) induced a time-dependent increase of the mitochondrial ROS level. Ir also increased mitochondrial membrane potential, mitochondrial respiration, and mitochondrial ATP production, suggesting upregulation of the mitochondrial electron transport chain (ETC) function after Ir. Although we found that Ir slightly enhanced mitochondrial ETC complex II activity, the complex II inhibitor 3-nitropropionic acid failed to reduce Ir-induced mitochondrial ROS production. Meanwhile, we observed that the mitochondrial mass and mitochondrial DNA level were upregulated after Ir, indicating that Ir increased the mitochondrial content of the cell. Because irradiated cells are known to undergo cell cycle arrest under control of the checkpoint mechanisms, we examined the relationships between the cell cycle and mitochondrial content and cellular oxidative stress level. We found that the cells in the G2/M phase had a higher mitochondrial content and cellular oxidative stress level than cells in the G1 or S phase, regardless of whether the cells were irradiated. We also found that Ir-induced accumulation of the cells in the G2/M phase led to an increase of cells with a high mitochondrial content and cellular oxidative stress level. This suggested that Ir upregulated mitochondrial ETC function and mitochondrial content, thereby resulting in mitochondrial ROS production and that Ir-induced G2/M arrest contributed to the increase in the mitochondrial ROS level by accumulating cells in the G2/M phase.

Excellent clinical results have been reported for total hip arthroplasty (THA) using a short stem. However, the range of variance in positioning of the stem has been reported to be wide. The authors hypothesized that the short stem position influences the femoral offset (FO) and hip abductor muscle strength (AMS) after surgery. The AMS was evaluated in 64 limbs in 32 patients who underwent unilateral THA using a short stem with a normal contralateral hip. The average time of AMS evaluation was 46.3 months postoperatively. The Harris Hip Score (HHS) was used for clinical evaluation. The ratio of the AMS on the reconstructed side to that on the contralateral side was calculated (strength ratio). The valgus angle (VA) of each stem and FO was measured on an anteroposterior hip radiograph. The FO ratio, as the normalized FO, was calculated. Linear regression analyses were performed to investigate the relationships among the VA, FO ratio and strength ratio. The average HHS improved from 57.7 points preoperatively to 94.6 points postoperatively. The VA negatively correlated with the FO ratio (r = −0.511, P = 0.028). The strength ratio negatively correlated with the VA (r = −0.505, P = 0.032) and positively correlated with the FO ratio (r = 0.479, P = 0.0056). The average postoperative HHS was generally satisfactory after THA using a short stem. A more valgus postoperative position of the short stem leads to reduced FO, which causes decreasing postoperative AMS after THA with a short stem.

A case of vessel perforation by a guide wire during an interventional neuroradiological procedure is reported. The patient was a 59-year-old woman with a left frontal basal arteriovenous malformation (AVM) fed by the left anterior cerebral artery. Transarterial embolization of the AVM was attempted. During the procedure, vessel perforation by the guide wire occurred at the left A1-A2 junction and resulted in subarachnoid hemorrhage, which stopped spontaneously. The patient developed progressive obstructive hydrocephalus, and surgical treatment was performed. The AVM was totally removed after ventricular drainage, and the arterial perforation site was explored. When clot around the left A1-A2 junction was removed, hemorrhage recurred. This hemorrhage was similar to what has been observed when a small perforating artery was avulsed. The hemorrhage site was coagulated under temporary occlusion of both A1 segments. Surgical intervention was probably not necessary for this type of bleeding if it had stopped spontaneously, because the rebleeding from the small pinhole would be unlikely, and the operation was more hazardous than the usual aneurysmal surgery.

In recent years, the number of three-phase squirrel-cage induction motors fed by inverters has increased due to the benefits of high efficiency and variable speed control. Motors driven by inverters produce electromagnetic vibrations caused by many time-harmonic voltages as well as by the fundamental voltage. To reduce the electromagnetic vibration, it is necessary to determine the relationship between time-harmonic voltages and electromagnetic vibration.In this paper, two kinds of time-harmonic voltages superimposed on the fundamental voltage with various phase angles are supplied to the motor at no-load, and the causes of the dominant electromagnetic vibration are analyzed. First, the effects of amplitudes and phase angles of harmonic voltages on the electromagnetic vibration are theoretically studied and characterized. Next, the theoretical results are experimentally verified. It is determined that the characteristics of the dominant electromagnetic vibration can be classified into the following three categories:(1) the vibration is proportional to the amplitude of one harmonic voltage, (2) the vibration is proportional to the product of amplitudes of two harmonic voltages, (3) the vibration varies complicatedly with amplitudes and phase angles of two harmonic voltages.

The effects of amlodipine, a Ca2+-channel blockade, on hemodynamic and hormonal responses to exercise were evaluated in patients with essential hypertension. In 7 patients (WHO stage, I, II), the exercise by bicycle ergometer was done before and after amlodipine treatment (5mg/day, 2-4wk). The hemodynamic responses to exercise were evaluated by changes in systolic and diastolic blood pressure, heart rate, cardiac output measured by UCG, and total peripheral resistance. In addition, plasma norepinephrine concentration (PNE) and renin activity (PRA) were measured at rest and peak exercise. A significant rise in systolic and diastolic blood pressure associated with tachycardia was observed during exercise. An increase in cardiac output was also observed, but the total peripheral resistance decreased by exercise. The PNE and PRA were increased by exercise. Amlodipine reduced both basal blood pressure and exercise-induced rise in blood pressure. On the other hand, the basal heart rate and exercise-induced increase in heart rate were not affected by amlodipine treatment. These changes were similar to those in pretreatment of amlodipine. Amlodipine did not produce any significant changes in PNE both at rest and during exercise. Although the PRA at rest was increased by amlodipine treatment, the increase in PRA induced by exercise was unaffected by amlodipine. These findings indicate that amlodipine might have some different effects on hemodynamics and hormones compared with the other Ca2+-channel blockades which produce an enhanced response of hemodynamics and hormonal system to exercise.

Background: Osteoporosis is a potential risk factor affecting implant stability following total joint arthroplasty. Bisphosphonates are potent inhibitors of osteoblastic bone resorption, and vitamin D is an important hormone involved in the regulation of calcium metabolism. We investigated the benefit of preoperative treatment with alendronate, vitamin D (calcitriol), or a combination of these substances on fixation of hydroxyapatite-coated implants in an ovariectomized rat model of osteoporosis. Methods: Of sixty-four female rats in the study, fifty-six underwent ovariectomy and eight, a sham operation. A hydroxyapatite-coated femoral implant and an uncoated implant were implanted in all rats seven months after the ovariectomy or the sham operation. Of the fifty-six rats that underwent ovariectomy, eight served as the control group. The remaining forty-eight were treated with alendronate, calcitriol, or a combination of these agents either starting eight weeks before implantation of the rod or starting immediately after implantation. The treatment was continued until four weeks after the implantation. Four weeks after the implantation, the total and cancellous bone mineral density at the proximal part of the tibia and the shear strength of the bone-implant interface were measured in all rats. Results: Although total bone mineral density increased in all of the alendronate-treated groups, compared with that in the ovariectomized control group, cancellous bone mineral density increased only in the group pretreated with both alendronate and calcitriol. The implant stability in the ovariectomized control rats was significantly decreased compared with that in the sham-operation rats. While treatment with alendronate only or calcitriol only did not improve the stability of the implants, treatment with a combination of alendronate and calcitriol, starting preoperatively, significantly improved the stability of the hydroxyapatite-coated implants. Conclusions: Treatment with a combination of alendronate and calcitriol, starting preoperatively, can improve cancellous bone mineral density and the stability of hydroxyapatite-coated implants in an osteoporotic rat. Conclusions: Clinical Relevance: Patients who receive alendronate and vitamin D for the treatment of osteoporosis before cementless joint arthroplasty may have more stable fixation of the implants.

A 61-year-old man presented with the complaint of headache. Investigations revealed a fusiform middle cerebral artery aneurysm at the M2 part. The formation of the aneurysm rapidly developed to a partially thrombosed aneurysm in the course of four months. As regards the treatment of the aneurysm, at first we tried surgery with a superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and trapping of the aneurysm. However, during the procedure, it was difficult to control bleeding from the temporal muscle, bone flap, and subdural space. Because of this, we finished the STA-MCA bypass without trapping of the aneurysm and then, four days later, we confirmed bypass patency and treated the aneurysm using endovascular coil embolization. Based on both surgical and interventional investigations in this case and a review of the reported literature, the authors propose that there are two mechanisms causing the middle cerebral artery fusiform aneurysm to develop thrombosed formation rapidly: (i) Peripheral middle cerebral artery branches demand less blood flow than other major trunk arteries. (ii) Bypass flow maintains perfusion to the distal branches. On the other hand, this flow alteration caused by surgical vascular bypass may promote the development of the aneurysm to thrombosed formation. The treatment of a fusiform middle cerebral artery aneurysm at the M2 part is also discussed.

We retrospectively evaluated 17 hips in 16 patients who underwent a periacetabular osteotomy for the treatment of dysplastic hip with Perthes-like deformities. These residual deformities were graded using the Stulberg classification system. There were three class II hips, 11 class III hips and three class IV hips preoperatively. The average age of the patients at surgery was 36.9 years and the average follow-up was 6.6 years. The average Harris hip score significantly improved from the preoperative value of 68.2 points to 91.1 points postoperatively. The average postoperative range of motion in all directions did not change significantly from the preoperative value. The average postoperative Harris hip score of class IV hips was smaller than that of the class II or class III hips. The standard radiographic evaluations also showed significant improvements postoperatively. Periacetabular osteotomy without combined femoral osteotomies, as a treatment for patients with Perthes-like deformities, produced good clinical and radiographic results.

The presence of subchondral bone cysts reflects degeneration or defects of the articular cartilage and elevated local stresses in the subchondral bone. We asked whether the presence of acetabular cysts deleteriously influenced the clinical and radiographic results of periacetabular osteotomy for treatment of dysplastic hips. We retrospectively reviewed 46 hips in 43 patients with cartilage narrowing who had periacetabular osteotomies. Of the 46 hips, 21 had acetabular cysts (cyst group) and 25 did not (control group). The average followups were 5.8 and 5.4 years in the cyst and control groups, respectively. We compared the Harris hip score and coverage of the femoral head between the two groups. The clinical results were similar between the two groups. There were no differences in radiographic evaluations between the two groups at the latest followup. In the cyst group, complete or partial healing of the cysts was observed in 17 of the 21 hips. A postoperative increase in the center-edge angle of 20 degrees or greater was found in 14 of the 17 hips. The preoperative presence of acetabular cysts did not influence the results of periacetabular osteotomy. Adequate rotation of the acetabular fragment induced cyst remodeling.

The existing methods of assessing limb lengthening during total hip arthroplasty (THA) are prone to error because the measurements are not parallel to the limb lengthening axis. In order to address this, we designed a caliper to estimate limb lengthening during THA and evaluated its accuracy compared with our previous device, the straight caliper. Limb lengths were measured in 100 patients. The L-shaped caliper was used in 50 cases and the straight caliper in 50. The correlation between intra-operative and post-operative radiographic measurements was significantly improved using the L-shaped device (p < 0.0001, r = 0.934). This method was extremely accurate in predicting changes in limb length due to surgery.

We investigated the prevalence and characteristics of ischemic heart disease especially silent myocardial ischemia (SMI) and arrhythmia in need of careful observation in the exercise stress tests in the Total Health Promotion Plan (THP), which was conducted between 1994-96 for the purpose of measuring cardiopulmonary function. All workers (n = 4,918, 4,426 males) aged 18-60 yr old in an occupational field were studied. Exercise tests with an ergometer were performed by the LOPS protocol, in which the maximal workload was set up as a presumed 70-80% maximal oxygen intake, or STEP (original multistage protocol). ECG changes were evaluated with a CC5 lead. Two hundred and fifteen people refused the study because of a common cold, lumbago and so on. Of 4,703 subjects, 17 with abnormal rest ECG and 19 with probable anginal pain were excluded from the exercise tests. Of 4,667 who underwent the exercise test, 37 (0.79%) had ischemic ECG change, and 155 (3.32%) had striking arrhythmia. These 228 subjects then did a treadmill exercise test with Bruce protocol. Twenty-two (0.47% of 4,703) showed positive ECG change, 9 (0.19%) of 22 had abnormal findings on a 201Tl scan. 8 (0.17%) were diagnosed as SMI (Cohn I), in which the prevalence of hypertension, hyperlipidemia, diabetes mellitus, smoker and positive familial history of ischemic heart disease was greater than that of all subjects. In a 15-30 month follow up, none has developed cardiac accidents. Exercise-induced arrhythmia was detected in 11 (0.23%) subjects. Four were non-sustained ventricular tachycardia without any organic disease, 4 were ventricular arrhythmia based on cardiomyopathy detected by echocardiography, 2 were atrial fibrillation and another was WPW syndrome. It is therefore likely that the ergometer exercise test in THP was effective in preventing sudden death caused by ischemic heart disease or striking arrhythmia.

BACKGROUND The efficacy of preoperative embolization for hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries was examined. CASES AND METHODS Five hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries, four posterior ethmoidal arteries, one anterior falx artery, and one recurrent middle meningeal artery were embolized with Gelfoam powder, polyvinyl alcohol (PVA) particles, and/or microcoils as a preoperative treatment using a microcatheter. RESULTS Catheterization of the ophthalmic and tumor feeding artery was possible and feeding arteries and lesion embolization were effective to reduce the bleeding during surgery in all cases. In three cases, visual acuity and visual field were preserved. However, in one case, visual acuity and visual field defect appeared due to the migration of Gelfoam powder (Upjohn, Kalamazoo, MI) into the retinal artery. In another case, the retinal artery was embolized with the feeding arteries since the patient was already blind. CONCLUSION Embolization of hypervascular meningioma feeding vessels arising from the ophthalmic artery is possible and effective with preservation of vision, if embolic agents are injected gently enough not to reflux into the central retinal artery.

1. This study was carried out to evaluate the effect of temocapril on haemodynamic and humoral responses to exercise in nine patients with mild essential hypertension (WHO stages I and II). 2. After a 4-week placebo period, temocapril was administered at a dose of 1.0 mg once daily for 2-4 weeks. Graded submaximal bicycle ergometer exercise was performed before and after temocapril treatment, and the changes in arterial blood pressure, heart rate, cardiac output (CO), and systemic vascular resistance (SVR) were evaluated. In addition, the plasma norepinephrine (NE) level was determined both at rest and peak exercise before and after temocapril treatment. 3. Both the systolic and diastolic blood pressure were reduced at rest and during exercise by temocapril treatment. No significant change in the resting heart rate and CO was observed, and the exercise-induced increase of these parameters was also not affected by temocapril. In contrast, the resting SVR was significantly decreased by temocapril, although the exercise SVR was similar during both temocapril and placebo treatment. 4. Although there was no significant change in the plasma NE level with temocapril treatment, the exercise-induced increase of plasma NE was significantly suppressed by temocapril. 5. These results indicate that temocapril reduces the blood pressure without causing any significant changes in the heart rate and CO at rest, and that it does not produce any changes in the haemodynamic response to exercise.

It is well known that neurofibromatosis is associated with various types of arteriovenous fistulas (AVF), but association with an occipital AVF has not been reported. We are reporting this case which was successfully treated with a combination of embolization and surgery. Superselective angiography defines the anatomic details of the fistula and intraoperative digital subtraction angiography (DSA) facilitates the surgery to cure the fistula. It is important to identify the best therapeutic options using angiographic information to treat a complex arteriovenous fistula.

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 × 2.0 mm in the deflated condition and became 2.2 × 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

✓ The authors report three cases of arteriovenous malformations (AVM's) with aneurysms arising from the feeding artery; all were successfully treated with a new nonadhesive liquid embolic material, ethylene vinyl alcohol copolymer (EVAL). In two patients the AVM's were totally removed without difficulty, and in one the AVM was managed conservatively after embolization. No new neurological deficits appeared during or after embolization. After road-mapping techniques, EVAL was injected slowly until the feeding artery and aneurysm were completely obliterated. This embolic agent is easy to handle and is considered safe compared with other adhesive liquid embolic agents, such as isobutyl-2-cyanoacrylate or n-butyl cyanoacrylate. It is concluded that EVAL is an excellent agent for embolizing an AVM with a peripheral aneurysm on the feeding artery.

Dynamic computed tomography (DCT) was evaluated as a diagnostic indicator for chronic supratentorial ischemia in 50 cases with or without minor neurological deficits. Peak height (PH, the maximum value of the gamma fitted curve), peak time (PT, the time to PH from the start of DCT), transit time (TT, the time between the first and second inflection points of the gamma fitted curve), and their functional maps were analyzed. Cerebral angiography was then performed in all cases to identify stenotic or occlusive vascular lesions in major cerebral arteries. DCT clearly detected 12 of 13 occlusions of the internal carotid artery (ICA) or middle cerebral artery (MCA), although one ICA occlusion was masked by the contralateral MCA occlusion. However, DCT detected only severe ICA or MCA stenosis (more than 90%). Probably, stenotic lesions of less than 90% did not cause detectable hemodynamic compromise. DCT using PH, PT, and TT functional maps is a useful diagnostic method for hemodynamic changes in ischemic cerebrovascular disease, although bilateral lesions and less stenotic lesions (less than 90%) are difficult to detect.

Abnormalities of Ca2+ handling have been reported in patients with essential hypertension and in spontaneously hypertensive rats (SHR). In this study, responses of cytosolic Ca2+ to ADP in platelets of SHR were examined. Four- and seven-week-old male SHR and age- and sex-matched Wistar-Kyoto rats (WKY) were used. Basal levels of the intracellular Ca2+ concentration in platelets and responses to ADP were estimated using fluorescent indicator fura-2 in the medium containing 1 mmol/L CaCl2 and Ca2(+)-free buffer with 1 mmol/L EGTA. Basal levels of platelet cytosolic Ca2+ of SHR were significantly higher than those of WKY at 4 and 7 weeks of age in the presence of external Ca2+. However, no significant difference was observed in basal levels of platelet cytosolic Ca2+ in the Ca2(+)-free EGTA-containing buffer between SHR and WKY. The peak cytosolic Ca2+ concentration evoked by ADP was significantly diminished in SHR compared with WKY in the absence of external Ca2+, whereas the responses of platelet cytosolic Ca2+ to ADP were similar in SHR and WKY in the presence of external Ca2+. These results suggest that release from intracellular Ca2+ store is reduced in SHR and that the regulation of cytosolic Ca2+ in SHR is more dependent on extracellular Ca2+ compared with WKY.