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Biomedical subjects

N Sugano

Publications and source records attributed to N Sugano.

At least 19 recordsLinked to original sources
PubMed2006

Disorders of acetabular labrum and articular cartilage in hip dysplasia: evaluation using isotropic high-resolutional CT arthrography with sequential radial reformation.

OBJECTIVE: Acetabular labral tear may predispose to adjacent articular cartilage disorder and hip osteoarthritis in patients with hip dysplasia. We evaluated the diagnostic ability of isotropic computed tomography (CT) arthrography with radial reformation technique for detection of acetabular labral and articular cartilage disorders, and evaluate those interactions in hip dysplasia. METHODS: Forty-one hips in 29 patients with hip dysplasia received CT arthrography with isotropic spatial resolution of 0.5mm. After processing of multiplanar radial reformation over the whole acetabular circumference, frequencies of labral tear and acetabular cartilage disorder were evaluated at six divided zones of the weight-bearing areas. Of the 41 hips, 20 hips underwent arthroscopic examinations, and sensitivity, specificity and accuracy for detecting labral tear and acetabular cartilage disorder by CT arthrography were calculated using the arthroscopic findings as the standard of reference. RESULTS: The sensitivity, specificity and accuracy of CT arthrography were 97%/87%/92% for labral tear and 88%/82%/85% for acetabular cartilage disorder, respectively, using arthroscopic findings as the reference. The CT arthrography showed significantly higher frequency of labral and acetabular cartilage disorders at the anterior zones. Those zones with labral tear had significantly higher frequency of adjacent cartilage disorder than zones without labral tear. CONCLUSIONS: Isotropic CT arthrography with radial reformation technique allowed simultaneous, accurate assessment of labral and cartilage disorders in the whole acetabular circumference. Our findings indicated that labral tear is closely associated with adjacent cartilage disorder in hip dysplasia.

Acetabulum↗
PubMed2006

Service comparison between vascular and general surgery in the treatment of chronic venous insufficiency with special reference to preoperative Doppler techniques.

AIMS: To compare the ability of vascular and general surgical services to abolish reflux in superficial venous system with a special reference to preoperative use of Doppler techniques. MATERIALS AND METHODS: 68 lower limbs operated on for venous insufficiency based on either preoperative Duplex evaluation and Doppler marking in a vascular surgical unit (Vascular Surgical Service, VSS: 33 limbs, clinical class C2-C6) or clinical findings in a general surgical unit (General Surgical Service, GSS: 35 limbs, clinical class C2-C4) were re-examined clinically and with duplex scanning for reflux some three years postoperatively. RESULTS: Marked superficial or perforator vein reflux was observed in 27 of 68 (39.7 %) operated limbs, thirteen of which in VSS and fourteen in GSS. However, axial reflux at saphenofemoral or thigh level was observed significantly less in VSS compared to GSS (3 vs 13, p = 0,006). CONCLUSION: Total ablation of any reflux appeared difficult irrespective of the preoperative assessment. Preoperative Duplex examination, however, aided in identifying and treating axial reflux at thigh level.

Adult↗
PubMed2005

Development of the needle insertion robot for percutaneous vertebroplasty.

Percutaneous Vertebroplasty (PVP) is an effective and less invasive medical treatment for vertebral osteoporotic compression fractures. However, this operative procedure is quite difficult because an arcus vertebra, which is narrow, is needled with accuracy, and an operator's hand is exposed to X-ray continuously. We have developed a needle insertion robot for Percutaneous Vertebroplasty. Its experimental evaluation on the basic performance of the system and needle insertion accuracy are presented. A needle insertion robot is developed for PVP. This robot can puncture with accuracy and an operator does not need to be exposed to X-ray. The mechanism of the robot is compact in size (350 mm x D 400 mm x H270 mm, weight: 15 kg) so that the robot system can be inserted in the space between C-arm and the patient on the operating table. The robot system is controlled by the surgical navigation system where the appropriate needle trajectory is planned based on pre-operative three-dimensional CT images. The needle holding part of the robot is X-ray lucent so that the needle insertion process can be monitored by fluoroscopy. The position of the needle during insertion process can be continuously monitored. In vitro evaluation of the system showed that average position and orientation errors were less than 1.0 mm and 1.0 degree respectively. Experimental results showed that the safety mechanism called mechanical fuse released the needle holding disk properly when excessive force was applied to the needle. These experimental results demonstrated that the developed system has the satisfactory basic performance as needle insertion robot for PVP.

Bone Cements↗
PubMed2005

Treatment of three pancreaticoduodenal artery aneurysms associated with coeliac artery occlusion and splenic artery aneurysm: a case report and review of the literature.

A case of three pancreaticoduodenal artery (PDA) aneurysms associated with coeliac artery occlusion and a concomitant splenic arterial aneurysm is described. Surgical treatment was used because it was anticipated that the hepatic blood supply would be obstructed completely if percutaneous transluminal embolization for three PDA aneurysms were performed. Splenectomy in continuity with the splenic artery aneurysm and PDA aneurysmectomies were performed, and infrarenal abdominal aorto-splenic artery bypass was accomplished using a 6mm ringed expanded polytetrafluoroethylene graft. The postoperative course was uneventful. Graft patency and successful aneurysm ablation were confirmed using MRA and intravenous DSA. Arterial histology revealed segmental arterial mediolysis. At 2-year follow-up, the patient was well and asymptomatic. A literature review of PDA aneurysms is presented.

Aneurysm↗
PubMed2005

Characteristics of peripheral microembolization during iliac stenting: Doppler ultrasound monitoring.

OBJECTIVE: To evaluate the characteristics of distal microembolic signals (MES) during iliac stenting using Doppler ultrasound monitoring. DESIGN: Prospective clinical study. METHODS: A 2-MHz probe was used to monitor continuously at the ipsilateral tibioperoneal trunks during technically and hemodynamically successful iliac stenting in 10 patients without infrainguinal occlusive lesion. MESs at guide-wire, balloon, or stent crossing (phase 1), predilatation (phase 2), stent deployment (phase 3), postdilatation (phase 4), and contrast medium or heparinized saline injection (at injection) were analyzed. Differentiation of gaseous emboli from particulate emboli was achieved by calculation of the sample volume length. RESULTS: No distal embolic complications were observed. Five hundred and forty-one MESs were detected. The MES incidence and intensity in phase 3 were significantly higher than those in phase 1, phase 2, and phase 4 (p<0.05). The MES intensity at injection was significantly higher than that in each of four phases (p<0.0001). CONCLUSIONS: Both the MES incidence and intensity were highest at stent deployment. Further study is required of microembolism during endovascular procedures in the lower extremities.

Aged↗
PubMed2005

Detection of periodontopathic bacteria and an oxidative stress marker in saliva from periodontitis patients.

We assessed the salivary levels of periodontopathic bacteria and 8-hydroxydeoxyguanosine (8-OHdG) in patients with periodontitis. The salivary levels of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia (formerly Bacteroides forsythus) were assessed using real-time polymerase chain reaction. The 8-OHdG levels were determined using an enzyme-linked immunosorbent assay. The salivary levels of 8-OHdG, P. gingivalis, and T. forsythia in the periodontitis patients were significantly higher than those in healthy subjects. By contrast, the A. actinomycetemcomitans level in healthy subjects was higher than that in periodontitis patients. 8-OHdG was significantly correlated with P. gingivalis. Statistically significant decreases in the levels of P. gingivalis, probing depth, bleeding on probing, and 8-OHdG were observed after initial periodontal treatment. These results suggest that the 8-OHdG levels in saliva reflect the load of periodontal pathogens. 8-OHdG could be a useful biomarker for assessing periodontal status accurately, and for evaluating the efficacy of periodontal treatment.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2004

Preservation of venous valve function after catheter-directed and systemic thrombolysis for deep venous thrombosis.

OBJECTIVES: The aim of the study was to assess venous reflux and the obstruction pattern after catheter-directed and systemic thrombolysis of deep iliofemoral venous thrombosis. PATIENTS: Thirty-two patients treated either with systemic (16) or catheter-directed local thrombolysis (16) for massive iliofemoral thrombosis were identified from the hospital registry. METHODS: Clinical evaluation at follow up was based on the CEAP classification and disability score. Reflux was assessed by colour duplex ultrasonography and standardised reflux testing. A vascular surgeon blinded to treatment established the clinical status of the lower limb following the previous DVT. RESULTS: Valvular competence was preserved in 44% of patients treated with catheter-directed thrombolysis compared with 13% of those treated with systemic thrombolysis (p=0.049, Chi squared). Reflux in any deep vein was present in 44% of patients treated by catheter-directed lysis compared with 81% of patients receiving systemic thrombolysis (p=0.03, Chi squared). Reflux in any superficial vein was observed in 25% vs. 63% of the patients, respectively (p=0.03, Chi squared). There were significantly more patients with venous insufficiency of classes C0-1 in the group treated with catheter-directed thrombolysis. CONCLUSION: In this clinical series venous valvular function was better preserved after iliofemoral DVT when treated with catheter-directed thrombolysis.

Adult↗
PubMed2004

Analysis of a retrieved UHMWPE acetabular cup crosslinked in air with 1000 kGy of gamma radiation.

The oxidation and degradation that accompany high dose gamma irradiation in air for crosslinking and sterilization are important because they could affect the clinical performance of polyethylene total joint implants. We report a clinical case of a 1000 kGy gamma-irradiated, highly crosslinked ultra-high molecular weight polyethylene acetabular cup retrieved 24 years postoperatively. Performance evaluations included absorbed radiation dose, total wear penetration, average wear rate, crystallinity, oxidation, and equibiaxial tensile properties. A retrieved acetabular cup of the same grade of polyethylene but gamma-sterilized using a conventional dose was used as control. The highly crosslinked and control cups took in about 1300 and 30 kGy of radiation, respectively, as measured using a trans-vinylene index. Direct dimensional measurements revealed average wear rates of the highly crosslinked and control cups were 0.04 and 0.06 mm/year, respectively. The oxidation index of the highly crosslinked cup was very high (0.679), but equivalent to that of a 1000 kGy irradiated reference cup. The retrieved highly crosslinked cup showed much higher equibiaxial ultimate tensile strength than the retrieved control cup. Based on these observations, the increased wear resistance and equibiaxial tensile properties that resulted from extensive crosslinking in the presence of air were partially offset by the adverse effects caused by immediate oxidation during the process.

Aged↗
PubMed2004

Differential cytokine induction by two types of Porphyromonas gingivalis.

The presence of Porphyromonas gingivalis with type II fimA is strongly associated with adult periodontitis. However, the importance of specific fimA types in the immune response is unknown. Two types of P. gingivalis (type I and type II) and Actinomyces naeslundii were assessed for their degree of cytokine induction in the macrophage-like human cell line U937. Real-time reverse transcriptase polymerase chain reaction was used to determine mRNA expression of 12 cytokines. Significant levels of interleukin (IL)-8 induction and a similar cytokine expression pattern were observed at 6 h postinfection for all three bacterial strains. However, type II P. gingivalis infection showed statistically higher levels of IL-1beta, IL-8, IL-12 and tumor necrosis factor-alpha mRNA induction than those of control at 24 h postinfection, whereas type I P. gingivalis and A. naeslundii showed no significant induction of these cytokines. These data suggest that compared with A. naeslundii and type I P. gingivalis, type II P. gingivalis prolongs the cytokine response. Although other factors may also be involved, the sustained cytokine response induced by type II P. gingivalis may play an important role in enhanced periodontal tissue inflammation and destruction.

Actinomyces↗
PubMed2004

Detection of Epstein-Barr virus in saliva by real-time PCR.

The purpose of this investigation was to assess the salivary levels of Epstein-Barr virus (EBV) in patients with periodontitis using real-time PCR. EBV was detected in 16 out of 33 (48.5%) periodontitis patients and in 3 out of 20(15%) healthy subjects. The baseline mean values for bleeding on probing in EBV-positive patients were significantly higher than those in EBV-negative patients. A significant decrease in EBV levels was observed after initial periodontal treatment. Our findings indicate that levels of EBV in saliva may reflect the status of periodontal inflammation.

Adult↗
PubMed2004

Preservation of the bone mineral density of the femur after surface replacement of the hip.

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B. The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery.

Absorptiometry, Photon↗
PubMed2003

Detection of Streptococcus anginosus from saliva by real-time polymerase chain reaction.

AIMS: The purpose of the present investigation was to assess the salivary levels of Streptococcus anginosus in periodontitis patients. METHODS AND RESULTS: The salivary levels of Strep. anginosus were assessed using real-time polymerase chain reaction (PCR). Streptococcus anginosus was detected in 28 of 37 (75.6%) of periodontitis patients and in three of the 20 (15%) healthy subjects. The mean values for bleeding on probing and probing depth in positive patients were statistically higher than those in negative patients. A significant decrease in Strep. anginosus levels was observed after periodontal treatment. CONCLUSIONS: Although the levels of Strep. anginosus are extremely low, they may reflect the status of periodontal health. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time PCR is a useful method for obtaining the relative quantities of Strep. anginosus from saliva samples and for monitoring the effect of therapy.

Adult↗
PubMed2003

Evaluation of buttock claudication with hypogastric artery stump pressure measurement and near infrared spectroscopy after abdominal aortic aneurysm repair.

OBJECTIVE: We explored the usefulness of intraoperative measurement of hypogastric artery (HGA) stump pressure (HGA-SP) and postoperative near infrared spectroscopy (NIRS) in evaluating buttock claudication (BC) after abdominal aortic aneurysm (AAA) repair. DESIGN: Retrospective clinical study. PATIENTS AND METHODS: Twenty patients who were undergoing AAA repair were enrolled. The HGA was ligated bilaterally in 5 patients, unilaterally in 12, and preserved in 3. The HGA-SP was measured intraoperatively. Postoperatively, NIRS was used to evaluate buttock muscle ischemia during walking. RESULTS: Six patients had unilateral and 1 bilateral BC after AAA repairs. The median HGA-SP brachial pressure index (HBI) was 0.62 (range: 0.45-0.64) in 8 claudicating buttocks and 0.76 (range: 0.63-0.90) in 13 asymptomatic buttocks (p < 0.0005). The HBI was <0.65 in all claudicating buttocks, whereas it was >0.63 in asymptomatic buttocks. In all 8 claudicating buttocks, NIRS showed the ischemic pattern with recovery time lasting more than 240 s. CONCLUSIONS: An HBI below 0.65 may be a predictor of BC after AAA repair. NIRS appears to be a useful noninvasive method for evaluating BC after AAA.

Aged↗
PubMed2002

Doppler ultrasound monitoring for detection of microembolic signals in peripheral arteries.

OBJECTIVE: to use Doppler ultrasound to detect peripheral microemboluation. METHODS: standard Transcranial Doppler equipment was used to peripheral detect peripheral embolic high intensity transient signals (HITSs) in a pig model following injection of microparticles and atheroma, and in 23 patients who underwent open repair of an abdominal aortic aneurysm (AAA), six patients with blue toe syndrome and 10 age matched healthy subjects. RESULTS: the pig study showed increasing signal intensity with particle size. Particles of 100 (n=24), 200 (n=17), and 400 microm (n=31) elicited 14, 25, 33 dB signals, respectively (p<0.05). During AAA surgery, the intensity (median) of HITSs before clamping (n=226) and after declamping (n=1216) were 14, and 20dB, respectively (p<0.001). Quite a few HITSs were detected after surgery. In patients with blue toe syndrome, a total of 63 HITSs could be detected, and the frequency of HITSs (median: 5.72/30min) was significantly higher than that in patients with AAA before surgery (0.065/30min) (p<0.001). CONCLUSIONS: Doppler ultrasound technique may be a clinically useful test to guide the treatment of patients at risk of distal atheroembolic events.

Aged↗
PubMed2002

The proximal form of mural thrombus in aortoiliac occlusive disease using computed tomography.

BACKGROUND: It is important to know the nature of proximal thrombus in patients with aortoiliac occlusive disease (AIOD) when juxtarenal aortic clamping is scheduled. This study was aimed to evaluate the shape and nature of thrombi at several sites of the abdominal aorta in patients with AIOD using enhanced computed tomography (CT). Final judgment was made according to the operative findings. METHODS: Between the years 1999 and 2001, 22 patients, who underwent aortobifemoral bypass, were enrolled. The shape and nature of their thrombi were examined at 4 points (superior mesenteric, suprarenal, juxtarenal and infrarenal arteries at the level of the 2 cm before the renal artery) and 88 slices of CT were examined retrospectively. RESULTS: There was mural thrombus in 31 slices, which could be classified into 4 shapes (crescent-shaped: 10 cases; magatama: 2; wavy: 12; circular: 6). The wavy and circular shaped thrombi were found to be atheromatous. Nine cases (40.9%) on operative findings were atheroma (wavy: 4; circular shaped: 5). The crescent shape might correspond to fibrin thrombus. Atheromatous thrombus clamping near the renal artery was thought to cause microthromboembolism to surrounding organs. CONCLUSIONS: It is recommended that the more proximal aorta or splanchnic arteries should be temporarily clamped during proximal procedures in patients with wavy or circular shaped thrombi at the juxtarenal aorta to prevent kidney or bowel infarction.

Aged↗
PubMed2001

Nicotine inhibits UV-induced activation of the apoptotic pathway.

Although nicotine has been implicated as a potential factor in the pathogenesis of cancer in humans, its mechanism of action in the development of cancer remains largely unknown. Growing evidence indicates that the induction of apoptosis is an important mechanism in the prevention of cancer development. In the study presented here, we examined the effects of nicotine on the process of apoptosis. Preincubation of human cells with nicotine completely inhibited ultraviolet light (UV)-induced apoptosis. The inhibition of apoptosis by nicotine was correlated with the prevention of cytochrome c release and caspase activation, which are essential components of the UV-induced apoptotic pathway. Thus, our results suggest that the inhibition of apoptosis by nicotine contributes to the increased incidence of cancer in smokers.

Apoptosis↗
PubMed2001

Accuracy evaluation of surface-based registration methods in a computer navigation system for hip surgery performed through a posterolateral approach.

OBJECTIVE: Many computer navigation systems have recently been developed for brain surgery, and the use of such systems in orthopedic surgery is increasing. Intraoperative registration of preoperative images is one of the most important steps in controlling the overall accuracy of computer navigation systems. Various parameters, such as CT-scan slice thickness, reconstruction pitch, intraoperative data sampling area, and data sampling volume, may affect the accuracy of registration. The purpose of this study was to evaluate the effect of the aforementioned parameters on the accuracy of registration for hip surgery performed through a posterolateral approach, and to find a clinically suitable trade-off between accuracy and surgical invasiveness. MATERIALS AND METHODS: One cadaveric pelvis and one cadaveric femur were used for this study. Four alumina ceramic balls with a diameter of 28 mm and within 1 micrometer of sphericity were attached to the pelvis, and three similar balls attached to the femur, to determine relative position. CT-scan images of the pelvis and femur were obtained with a helical scanner. Three sets of slice thickness and slice pitch were chosen for data acquisition, and two additional sets of reconstructed data were made. Bone contours were extracted by cutting out the surrounding substrate at a given CT number threshold, and surface models of the bone were made from the resultant data. The positions of the pelvis and femur were tracked by LED markers attached to the bone using an optical three-dimensional position sensor (OPTOTRAK). Registration of the computer models to the real objects was performed by measuring the position of a certain number of surface points on each object with an OPTOTRAK pen-probe. RESULTS AND CONCLUSION: Slice thickness and reconstruction pitch affected the accuracy of registration. As the sampling area was expanded from the periarticular area to the distant peripheral area, accuracy increased slightly. Accuracy did not increase when the whole area was used, but in fact decreased, especially in the femur. The positive effect of increasing the number of sampling points was saturated at 30 points when the surface of the periarticular area was sampled. The following trade-off between accuracy and invasiveness, in terms of various parameters of preoperative and intraoperative data, is proposed as clinically optimal: perform the CT scan with 3-mm slice thickness and 1-mm reconstruction pitch, and sample the periarticular area with 30 sampling points. With these parameters, the accuracy of registration was 1.2 mm and 0.9 degrees of bias with 0.7 mm and 0.3 degrees of RMS in the pelvis, and 1.4 mm and 0.6 degrees of bias with 1.3 mm and 0.3 degrees of RMS in the femur.

Cadaver↗