Biomedical subjects

K Shimizu

Publications and source records attributed to K Shimizu.

At least 37 records · Page 2Linked to original sources

PubMed2005

Clinical outcomes of multilevel anterior corpectomy and fusion as a revision surgery of the cervical spine: report of seven cases.

STUDY DESIGN: Report of seven cases. OBJECTIVE: There is no general consensus on the best surgical procedures for late-onset complications of cervical operations. We reported seven patients who had been treated effectively by multilevel anterior corpectomy and fusion (ACF) as revision surgery of the cervical spine. SETTING: Gifu University Hospital, Gifu, Japan. METHOD: Multilevel ACF using autogenous fibular strut graft as revision surgery was performed on seven patients: four patients having disorders of adjacent discs after anterior discectomy and fusion and three patients having postlaminoplasty disorders. Japanese Orthopedic Association scores (JOA scores) of the cervical myelopathy and severity of radicular and axial pains were used to evaluate outcomes. RESULTS: Rigid osseous fusion was achieved in all patients. JOA scores of the cervical myelopathy and the radicular pain, which had worsened just before the revision surgery, were improved significantly. CONCLUSION: In the present seven patients who had variety of pathological conditions with various previous surgeries, multilevel ACF using strut graft was effective as a revision procedure in ameliorating their symptoms.

Adult↗

PubMed2005

Applicability of anti-neovascular therapy to drug-resistant tumor: suppression of drug-resistant P388 tumor growth with neovessel-targeted liposomal adriamycin.

Anti-neovascular therapy, one of the effective anti-angiogenic chemotherapy, damages new blood vessels by cytotoxic agents delivered to angiogenic endothelial cells and results in indirect eradication of tumor cells. We previously reported that liposomes-modified with a pentapeptide, Ala-Pro-Arg-Pro-Gly (APRPG-Lip) homing to angiogenic site, highly accumulated in tumor tissue, and APRPG-Lip encapsulating adriamycin (APRPG-LipADM) effectively suppressed tumor growth in tumor-bearing mice. In the present study, we examined the topological distribution of fluorescence-labeled APRPG-LipADM as well as TUNEL-stained cells in an actual tumor specimen obtained from Colon 26 NL-17 carcinoma-bearing mice. The fluorescence-labeled APRPG-Lip dominantly localized to vessel-like structure: a part of which was also stained with anti-CD31 antibody. Furthermore, TUNEL-stained cells were co-localized to the same structure. These data indicated that APRPG-LipADM bound to angiogenic endothelial cells and induced apoptosis of them. We also investigated the applicability of anti-neovascular therapy using APRPG-LipADM to ADM-resistant P388 solid tumor. As a result, APRPG-LipADM significantly suppressed tumor growth in mice bearing the ADM-resistant tumor. These data suggest that APRPG-LipADM is applicable to various kinds of tumor including drug-resistant tumor since it targets angiogenic endothelial cells instead of tumor cells, and eradicates tumor cells through damaging the neovessels.

Angiogenesis Inhibitors↗

PubMed2005

NK105, a paclitaxel-incorporating micellar nanoparticle formulation, can extend in vivo antitumour activity and reduce the neurotoxicity of paclitaxel.

Paclitaxel (PTX) is one of the most effective anticancer agents. In clinical practice, however, high incidences of adverse reactions of the drug, for example, neurotoxicity, myelosuppression, and allergic reactions, have been reported. NK105, a micellar nanoparticle formulation, was developed to overcome these problems and to enhance the antitumour activity of PTX. Via the self-association process, PTX was incorporated into the inner core of the micelle system by physical entrapment through hydrophobic interactions between the drug and the well-designed block copolymers for PTX. NK105 was compared with free PTX with respect to their in vitro cytotoxicity, in vivo antitumour activity, pharmacokinetics, pharmacodynamics, and neurotoxicity. Consequently, the plasma area under the curve (AUC) values were approximately 90-fold higher for NK105 than for free PTX because the leakage of PTX from normal blood vessels was minimal and its capture by the reticuloendothelial system minimised. Thus, the tumour AUC value was 25-fold higher for NK105 than for free PTX. NK105 showed significantly potent antitumour activity on a human colorectal cancer cell line HT-29 xenograft as compared with PTX (P<0.001) because the enhanced accumulation of the drug in the tumour has occurred, probably followed by its effective and sustained release from micellar nanoparticles. Neurotoxicity was significantly weaker with NK105 than with free PTX. The neurotoxicity of PTX was attenuated by NK105, which was demonstrated by both histopathological (P<0.001) and physiological (P<0.05) methods for the first time. The present study suggests that NK105 warrants a clinical trial for patients with metastatic solid tumours.

Animals↗

PubMed2005

Novel intramedullary plug with sliding mechanism used in revision total knee arthroplasty.

A novel intramedullary plug with sliding mechanism has been developed and evaluated clinically in the settings of revision total knee arthroplasty (TKA). The new plug consists of a pair of specially designed components. Each component is shaped like an obliquely cut cylinder. Postoperative plain radiographs of 8 arthroplasties that include 7 stemmed femoral components and 6 stemmed tibial components (total 13 regions) were examined. No radiolucent line between the cement and the cortical bone was observed. Plugging was complete in 11 regions. No migration of the plug was observed. Slight leak of the cement was observed in 2 of 7 femoral components, but not found in tibial components. Our study demonstrated the efficacy of the plug in occluding the femoral and tibial canal completely in 11 out of 13 regions in revision TKAs.

Aged↗

PubMed2005

Multiple organ failure caused by end-stage liver disease successfully treated with living donor liver transplantation using perioperative percutaneous cardiopulmonary support: a case report.

A 54-year-old female diagnosed with primary biliary cirrhosis (PBC) 10 years earlier was referred for a living donor liver transplant (LDLT). During her workup, she developed pulmonary edema and respiratory failure due to aspiration pneumonia, which required artificial ventilation. The PaO2/FiO2 (P/F) ratio at that time was 60. Although continuous hemodiafiltration (CHDF) and plasma exchange (PE) were initiated, improvement in the P/F ratio was limited to 133. As transplantation was the only approach to save this patient, we performed LDLT using a right lobe graft aided by percutaneous cardiopulmonary support (PCPS). The graft weight was 650 g and the graft weight/recipient weight ratio was 1.6%. During LDLT, the patient's cardiopulmonary function was stable with PCPS, and the surgical procedure was completed without complications. Following the surgery, she continued to have high-end inspiratory pressure and progressed to the chronic phase of adult respiratory distress syndrome (ARDS). We treated her with low-dose steroid therapy and she improved gradually. The patient was weaned off mechanical ventilation and was discharged approximately 25 weeks after LDLT. In the condition of cardiac or respiratory failure, cadaveric liver transplantation using plasmapheresis is contraindicated because of the associated high mortality rate. Our case suggests that if infections are controlled, a patient with multiple organ failure (MOF) due to end-stage liver disease might be successfully treated with LDLT aided by plasmapheresis and PCPS.

Cardiopulmonary Resuscitation↗

PubMed2005

Foramen magnum decompression for the treatment of Arnold Chiari malformation type I with associated syringomyelia in an elderly patient.

STUDY DESIGN: Report of a rare case of an elderly patient with late onset of Arnold Chiari malformation type I with associated syringomyelia that was successfully treated with foramen magnum decompression. OBJECTIVE: To report this rare case along with a literature review. SETTING: Gifu, Japan. METHODS: A 69-year-old woman with a 4-year history of dull pain in her right arm was referred to the clinic. After physical and radiographical examinations, she was diagnosed with Arnold Chiari malformation type I with associated syringomyelia. A foramen magnum decompression by the removal of the outer layer of the dura mater was performed. RESULTS: At 2 years postoperatively, MRI revealed a decrease in the size of the syringomyelia. Her symptoms had also remarkably improved. CONCLUSIONS: A rare case of symptomatic Arnold Chiari malformation type I with associated syringomyelia in an elderly woman was successfully treated with foramen magnum decompression by the removal of the outer layer of the dura mater.

Aged↗

PubMed2005

Tetraparesis due to exostotic osteochondroma at upper cervical cord in a patient with multiple exostoses-mental retardation syndrome (Langer-Giedion syndrome).

STUDY DESIGN: Case report of a severe upper cervical cord compression and tetraparesis by a massive cervical exostotic osteochondroma in a patient with multiple exostoses-mental retardation syndrome (Langer-Giedion syndrome; LGS). OBJECTIVE: To describe this very rare pathological condition and the results of surgical intervention. SETTING: Gifu, Japan. METHODS: A 23-year-old man was referred to our clinic because of progressing tetraparesis. He had previously been diagnosed with hereditary multiple exostoses and mental retardation. As he had not complained of any symptoms, his family only noticed the tetraparesis after advanced deterioration. His face possessed the pathognomic features of LGS. A postmyelogram CT scan demonstrated an exostotic mass arising from the left-side C2 pedicle with associated severe spinal cord compression. He was diagnosed with LGS. Hemilaminectomy on the left side and resection of the osteochondroma were performed. RESULTS: At 5 years postoperatively, a neurological examination showed the full return of all motor functions. The CT scan revealed no intracanalar recurrence of the tumor. CONCLUSION: In this case of severe tetraparesis due to cervical osteochondroma, decompression by hemilaminectomy provided excellent results. In patients with LGS and intracanalar osteochondroma, the neurological deficit may be masked by mental retardation. Hence, awareness of this pathological condition will help clinicians diagnose it at an early stage.

Adult↗

PubMed2005

Identification of human T cell epitopes in Japanese cypress pollen allergen, Cha o 1, elucidates the intrinsic mechanism of cross-allergenicity between Cha o 1 and Cry j 1, the major allergen of Japanese cedar pollen, at the T cell level.

BACKGROUND: Pollens from species of Cupressaceae family are one of the most important causes of respiratory allergies worldwide. In Japan, many patients with pollinosis have specific IgE to both pollens of Japanese cypress (Chamaecyparis obtusa) and Japanese cedar (Cryptomeria japonica). The sequences between Cha o 1 and Cry j 1, the major allergens of Japanese cypress and Japanese cedar pollens, respectively, are 80% identical. OBJECTIVE: This study was undertaken to identify T cell epitopes in Cha o 1, and to elucidate the mechanism of cross-allergenicity between Cha o 1 and Cry j 1, at the T cell level. METHODS: T cell epitopes in Cha o 1 were identified by the reactivity of T cell lines, generated from 19 patients, to stimulation with overlapping peptides. The subsets of T cell clones specific to rCha o 1 were determined according to their ability to produce IL-4 and IFN-gamma. Peptide specificities of two T cell clones were determined by stimulation with the peptides from Cha o 1 and Cry j 1. RESULTS: Four dominant and six subdominant T cell epitopes were identified in Cha o 1. While four T cell epitopes, p11-30, p211-230, p251-270 and p331-350, were common to Cha o 1 and Cry j 1, 4 T cell epitopes, p61-80, p71-90, p311-330 and p321-340, were considered to be unique to Cha o 1. The subsets of T cell clones were predominantly of T helper2-type. One T cell clone recognized p16-30, which is common to Cha o 1 and Cry j 1, but another recognized p321-330, which is unique to Cha o 1. CONCLUSION: Presence of both T cells reactive to T cell epitopes common to Cha o 1 and Cry j 1 and T cells specific to T cell epitopes unique to Cha o 1 in patients with pollinosis contributes to prolonged symptoms after the cedar pollen season in March and the following cypress pollen season in April.

Adult↗

PubMed2005

Anterior decompression and fusion for multiple thoracic disc herniation.

Multiple thoracic disc herniations are rare and there are few reports in the literature. Between December 1998 and July 2002, we operated on 12 patients with multiple thoracic disc herniations. All underwent an anterior decompression and fusion through a transthoracic approach. The clinical outcomes were assessed using the Frankel neurological classification and the Japanese Orthopaedic Association (JOA) score. Under the Frankel classification, two patients improved by two grades (C to E), one patient improved by one grade (C to D), while nine patients who had been classified as grade D did not change. The JOA scores improved significantly after surgery with a mean recovery rate of 44.8% +/- 24.5%. Overall, clinical outcomes were excellent in two patients, good in two, fair in six and unchanged in two. Our results indicate that anterior decompression and fusion for multiple thoracic disc herniations through a transthoracic approach can provide satisfactory results.

Aged↗

PubMed2005

[Perioperative management for lung cancer with interstitial pneumonia].

The purpose of this study was to review perioperative managements from the clinical features and the postoperative course of lung cancer patients with interstitial pneumonia (IP). Twenty-two patients with IP were divided into 2 groups: the acute exacerbation (AE) group (6 patients) and the non-acute exacerbation (NAE) group (16 patients). There was no significant difference in the patient background between the 2 groups. In hematological examination, KL-6 levels were significantly higher in the AE group than in the NAE group. There was no significant difference in the respiratory function tests in the both groups, and the heart rate after 2 flights test was significantly higher in the AE group than in the NAE group. There was no significant difference in operation-related factors, tumor-related factors and the postoperative course in the both groups. No postoperative death occurred in our 22 patients probably due to adequate treatments of IP which was managed by our detailed manual. Long-term follow-up for lung cancer patients with IP undergoing surgical intervention is needed to prevent AE.

Aged↗

PubMed2005

[Acute type A aortic dissection combined with surgical treatment with acute myocardial infarction].

Acute myocardial infarction, as a result of coronary malperfusion caused by acute type A aortic dissection, has been identified as one of significant factors relating to operative mortality. This complication could be diagnosed with a combination of electrocardiography and echocardiography in acute phase. However, the indication of coronary angiography and/or intervention has been controversial as it is time-consuming and renders additional stress to a critical patient requiring an emergency operation. We report a case of myocardial infarction successfully treated with percutaneous transluminal coronary angioplasty (PTCA) at first, after that, recognition of dissection of aorta necessitated subsequent surgical therapy. In this particular case, coronary intervention in advance proved to be mandatory.

Aortic Dissection↗

PubMed2005

[Surgical resection of T3 and T4 lung cancer].

Lung cancer invading neighboring anatomical structures such as the chest wall, pericardium, diaphragm, and left atrium are categorized as T3 or T4, which is regarded as locally advanced lung cancer. The purpose of this study was to evaluate results of surgical treatment of T3-4N0-2M0 non-small cell lung cancer according to involved organs. From 1981 to April 2005, 148 patients with lung cancer invading neighboring organs were surgically treated in our hospital. The 5-year survival was 41.4% in all cases. According to 5-year survival of clinical characteristics, the chest wall (parietal pleura) group (45.5%) had a significantly better prognosis compared with the left atrium (0%, p = 0.03) and diaphragm (0%, p = 0.04) groups. T3N0 (50.3%), IIB (55.4%), IIIA (44.6%), and complete resection groups (49.0%) showed a significantly better prognosis compared with T3N2 (27.9%, p = 0.01), III B (0%, p < 0.0001), and incomplete resection groups (13.9%, p < 0.0001), respectively. These results indicate that the prognosis of patients with N2 disease or incomplete resection remains poor in regardless with the type of involved organs.

Adult↗

PubMed2005

[Concomitant off-pump coronary artery bypass and left lower lobectomy for lung cancer with pneumoconiosis].

Surgical strategy for patients for lung cancer with coronary disease remains controversial. We performed concomitant off-pump coronary artery bypass grafting (off-pump CABG: OPCAB) and left lower lobectomy with ND 2a lymph nodes dissection for lung cancer with pneumoconiosis. After CABG, due to fixed adhesion of peribronchial lymph node, left lower lobectomy was hard to carry out. Postoperative management was done with much difficulty for massive sputum and pneumonia caused by chronic inflammatory lung disease. As a result, postoperative course has been uneventful for 2 years after operation. In the concomitant OPCAB and lung resection with chronic inflammatory lung disease, whether the synchronous or 2 periods operation was appropriate was still unknown. We think that careful pre- and intraoperative assessment for this disease is important.

Aged↗

PubMed2005

Peroxisome proliferator-activated receptor gamma ligand prevents the development of chronic pancreatitis through modulating NF-kappaB-dependent proinflammatory cytokine production and pancreatic stellate cell activation.

PURPOSE: Thiazolidinedione derivatives (TZDs) are known to be ligands of peroxisome proliferator-activated receptor gamma (PPARgamma). In this study, we investigated the effect of a TZD, troglitazone, on inflammation and fibrogenesis in the pancreas of an experimental model of chronic pancreatitis. MATERIAL AND METHODS: Male WBN/Kob rats with spontaneous chronic pancreatitis were fed rat chow containing 0.2% troglitazone from 1 to 4 months of age. Immunohistochemical studies of rat pancreas were carried out with monoclonal mouse antibody against human alpha-smooth muscle actin (alpha-SMA) or rabbit polyclonal antibody against collagen type I, collagen type III, or fibronectin. Cytokine production was measured by enzyme-linked immunosorbent assay. The inhibitory action of troglitazone on nuclear factor-kappaB (NF-kappaB) binding activity in activated macrophages was also investigated. RESULTS: Long-term administration of troglitazone reduced inflammatory cell infiltration and fibrosis in the pancreas of WBN/Kob rats, and expression of alpha-SMA, procollagen I, III, and fibronectin was significantly reduced by troglitazone. The increase in TNF-alpha production by activated macrophages was significantly decreased by troglitazone. Peritoneal macrophages isolated from WBN/Kob rats produced a large amount of TNF-alpha, whereas those from troglitazone-treated WBN/Kob rats produced only a marginal amount of TNF-alpha. Lipopolysaccharide-induced NF-kappaB binding activity in peritoneal macrophages was also significantly reduced by troglitazone. CONCLUSIONS: Troglitazone prevented the progression of chronic pancreatitis via inhibition of ECM synthesis and proinflammatory cytokine production mediated by the inhibition of NF-kappaB activity.

Actins↗

PubMed2004

Biomechanical properties of heat-treated bone grafts.

INTRODUCTION: A possible critical complication associated with banking bone is human immunodeficiency virus (HIV) infection. Recently, since the report of HIV infection in bone allografts from an HIV-seronegative donor, a more reliable method of sterilization for preserved bone graft has become necessary. Heat treatment of banking bone is one of the simple sterilization methods. This method is especially safe and practical for the prevention of HIV infection. MATERIALS AND METHODS: We previously reported a biological study on heat-treated bone graft. In that study, we showed that revascularization and new bone formation of bone graft after heat treatment at 60 degrees C was nearly the same as that of non-heat-treated bone graft, while at 100 degrees C, revascularization and new bone formation showed a significant delay. This time, we examined the change of mechanical strength of heat-treated bone grafts after transplantation in an experiment. To eliminate the problem of antigenicity of grafted bone, we used autografts, not allografts. Two types of heat-treated autografts were employed: heat-treated at 60 degrees C for 30 min and heat-treated at 100 degrees C for 5 min; as a control, fresh autografts were replaced in the left femur of rabbits. A strength test was performed for both the transplanted bone and the untreated intact right femur with time after transplantation. The strength test consisted of a compression test and torsional test, and the strength was compared between transplanted bone and the untreated intact right femur. RESULTS: In the compression test, the grafts heat-treated at 60 degrees C showed a strength ratio before transplantation of 97.3%. The strength ratio decreased to 63.5% at 18 weeks after transplantation. Then the strength ratio increased and recovered to 94.5% at 48 weeks after transplantation. However, the grafts heat-treated at 100 degrees C showed unsatisfactory mechanical strength, at 48 weeks the strength ratio was 60.1%, which was significantly lower compared with controls. In the torsional test, the grafts heat-treated at 60 degrees C showed almost the same strength observed in the compression test. However, the grafts heat-treated at 100 degrees C showed unsatisfactory mechanical strength: at 48 weeks, the strength ratio was 57.3%. CONCLUSION: Therefore, heat treatment at 60 degrees C is a useful sterilization method, not only in biological but also mechanical terms.

Animals↗

PubMed2004

Coherent shear phonon generation and detection with ultrashort optical pulses.

Using an optical technique we generate and detect picosecond shear and quasishear coherent acoustic phonon pulses in the time domain. Thermoelastic and piezoelectric generation are directly achieved by breaking the sample lateral symmetry using crystalline anisotropy. We demonstrate efficient detection in isotropic and anisotropic media with various optical incidence geometries.

Journal Article↗

PubMed2004

Cefoselis, a beta-lactam antibiotic, easily penetrates the blood-brain barrier and causes seizure independently by glutamate release.

Cefoselis is a widely used beta-lactam antibiotic, but occasionally induces seizures and convulsion in elder and renal failure patients. However, beta-lactams are known not to pass through the blood-brain barrier (BBB). In this study, we examined the BBB penetration of cefoselis in normal and renal failure rats by means of brain microdialysis. Cefoselis was dose-dependently appeared in brain extracellular fluid in proportion to its blood level. The elimination constant from brain extracellular fluid (apparent) was slightly lower than that from blood. These results indicated that cefoselis might penetrate the BBB or be discharged by a certain transport system. In contrast to the result of cefoselis, cefazolin, a leading drug of cephalosporins, could not be detected in the brain extracellular fluid after an intravenous injection. In renal dysfunction rats, the elimination half-lives of cefoselis from both blood and brain were extensively prolonged. This would be one of responsible factors inducing seizures seen in patients. However, the additional factor, such as decrease in brain function related to aging, would be involved in seizures in patient received cefoselis, because an extremely high dose was required to induce seizures even in renal failure rats. A local administration of cefoselis into the hippocampus through the microdialysis probe caused a striking elevation of extracellular glutamate, with a minimum increase in gamma-aminobutyric acid (GABA). However, a systematic cefoselis administration via the tail vein did not elevate extracellular glutamate and GABA concentrations in the hippocampus of renal failure rats that exhibited marked seizures. These results suggested that not the stimulation of glutamate release, but the blockade of GABA receptors might be responsible for the seizure induced by cefoselis.

Animals↗

PubMed2004

Implication of prostaglandin E(2) in TNF-alpha-induced release of m-calpain from HCS-2/8 chondrocytes. Inhibition of m-calpain release by NSAIDs.

OBJECTIVE: Calpains are known as Ca(2+)-dependent intracellular neutral cysteine proteases. However, m-calpain is detected in synovial fluid of arthritic joints and is shown to possess the proteoglycanase activity in vitro. The mechanism of m-calpain release into the extracellular spaces during arthritis has not yet been well characterized. In the present study, we have analyzed m-calpain release from cultured chondrocytes stimulated by a proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). The effects of non-steroidal anti-inflammatory drugs (NSAIDs) on m-calpain release were also examined. METHODS: Human chondrocytic HCS-2/8 cells were stimulated by TNF-alpha in the presence or absence of an NSAID. m-Calpain in the cells and culture medium was quantified by Western blot analysis using an anti-m-calpain antibody. Western blots were subjected to densitometric analysis and band intensities were determined. RESULTS: TNF-alpha (10 ng/ml) stimulated m-calpain release with transient increase in cellular m-calpain in HCS-2/8 cells. NSAIDs examined (aspirin, loxoprofen-SRS, diclofenac sodium, indomethacin and NS398) inhibited m-calpain release and production of prostaglandin E(2) (PGE(2)) induced by 10 ng/ml TNF-alpha. Exogenously added PGE(2) accelerated the release of m-calpain in response to a lower concentration of TNF-alpha (1 ng/ml). AH6809, an EP1/2 antagonist, but not SC19220 (an EP1 antagonist), effectively inhibited TNF-alpha-induced m-calpain release. In contrast, butaprost, an EP2 agonist, accelerated release of m-calpain by 1 ng/ml TNF-alpha. CONCLUSIONS: These results suggest that TNF-alpha stimulates upregulation and release of m-calpain in chondrocytic HCS-2/8 cells, and that stimulation of EP2-PGE(2) receptor by produced PGE(2) is deeply involved in this process.

Alprostadil↗