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Biomedical subjects

K Shimizu

Publications and source records attributed to K Shimizu.

At least 73 records · Page 4Linked to original sources
PubMed2003

Characterization of the development of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells during osteoinduction by rhBMP-2: a histochemical and ultrastructural study.

OBJECTIVE: To investigate the characteristics of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells induced by recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS: rhBMP-2 (5 microg) combined with atelocollagen was implanted into calf muscles of rats and removed on days 7, 10, 14, 21, or 28. Tissue sections were examined using: (i) hematoxylin/Alcian blue/Sirius red stain, (ii) enzyme histochemistry for alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase activity, (iii) immunohistochemistry for types I, II, and X collagen, and (iv) electron microscopy. RESULTS: On day 7, numerous fibroblast-like cells with ALP activity were present on the pellet rim. On day 10, chondroid matrix (CM) had formed, contained both type I collagen and proteoglycans, and often continued into the BMP pellet. On day 14, bone-like matrix formed around hypertrophic chondrocytes simultaneously with endochondral ossification. Coexpression of types I and II collagen within chondrocytes and osteocytes was observed throughout the time course of the experiment. CONCLUSION: These results suggest that fibroblast-like cells invading the pellet differentiate into chondrocytes and form CM under the scaffold of the carrier component. It appears that some chondrocytes change their phenotype to produce the bone-like matrix and remain within the endochondral bone. This process enables rapid osteogenesis to occur.

Acid Phosphatase↗
PubMed2003

Sudden onset of paraparesis caused by hypertrophy of the thoracic posterior longitudinal ligament.

STUDY DESIGN: Case report of a rare form of hypertrophy of the thoracic posterior longitudinal ligament (HPLL), causing paraparesis. OBJECTIVE: To describe this very rare pathological condition in the thoracic spine and the results of surgical intervention. SETTING: A department of orthopaedic surgery in Japan. METHODS: A 61-year-old man presented with acute paraparesis associated with HPLL in the thoracic region. A radiographic and pathological review of the case was conducted. Anterior decompression was performed, and he was followed for 3 years after the operation. RESULTS: Pathologic examination of the surgical specimen revealed proliferation of fibrocartilage and calcification. The patient's paraparesis ameliorated after the operation. CONCLUSION: For this case of myelopathy due to HPLL in the thoracic spine, urgent decompression gave excellent results. Clinical awareness of HPLL may aid correct diagnosis and prompt therapy.

Acute Disease↗
PubMed2003

Spinal subarachnoid hematoma compressing the conus medullaris and associated with neurofibromatosis type 2.

STUDY DESIGN: Report of a case of subarachnoid hematoma associated with neurofibromatosis type 2 (NF2) in a 10-year-old girl. OBJECTIVE: To report a rare case of subarachnoid spontaneous hematoma associated with NF2, with no evidence of trauma. SETTING: Gifu, Japan. METHODS: The patient presented with severe leg pain. MRI revealed a subarachnoid hematoma at the level of L2 and a spinal cord tumor at the level of T6. The subarachnoid hematoma had low and high heterogeneous signal intensity on the T1-weighted image and low signal intensity on the T2-weighted image, indicating the presence of extracellular methemoglobin. The tumor and hematoma were resected. RESULTS: Pathological analysis demonstrated that the surgical specimen removed from the area of L2 was a hematoma and the specimen from T6 was a neurinoma. At follow-up 1 year after surgery, the girl remained neurologically asymptomatic. CONCLUSIONS: This rare case of spinal subarachnoid hematoma was associated with NF2. MRI was useful in establishing the diagnosis.

Child↗
PubMed2003

Role of mitogen-activated protein kinases in influenza virus induction of prostaglandin E2 from arachidonic acid in bronchial epithelial cells.

BACKGROUND: Influenza virus (IV) infection causes airway inflammation; however, it has not been determined whether IV infection could catabolize arachidonic acid cascade in airway epithelial cells. In addition, the responsible intracellular signalling molecules that catabolize arachidonic acid cascade have not been determined. OBJECTIVE: In the present study, to clarify these issues, we examined the cyclooxygenase (COX) expression, cytosolic phospholipase A2 (cPLA2) phosphorylation and prostaglandin E2 (PGE2) release in human bronchial epithelial cells (BEC) upon IV infection, and the role of mitogen-activated protein kinase (MAPK) including extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun-NH2-terminal kinase (JNK) in catabolizing arachidonic acid cascade in BEC. METHODS: COX-2 expression, phosphorylation of cPLA2 and phosphorylation of ERK, JNK and p38 MAPK were determined by Western blot. The concentrations of PGE2 were determined by ELISA. PD 98059 as a specific inhibitor of MAPK kinase-1 (MEK-1), an up-stream kinase of ERK, SB 203580 as a specific inhibitor of p38 MAPK and CEP-11004 as a specific inhibitor of JNK cascade were used to investigate the role of ERK, p38 MAPK and JNK in catabolizing arachidonic acid cascade in BEC. RESULTS: The results showed that (1) IV infection increases COX-2 expression, cPLA2 phosphorylation and PGE2 release, (2) ERK, p38 MAPK and JNK were phosphorylated, (3) CEP-11004 and PD 98059 predominantly attenuated COX-2 expression and cPLA2 phosphorylation, respectively, (4) SB 203580 did not remarkably affect COX-2 expression and cPLA2 phosphorylation, and (5) each inhibitor dose-dependently attenuated PGE2 release by various extents. CONCLUSION: These results indicate that IV infection activates three distinct MAPKs, ERK, p38 MAPK and JNK, to participate to various extents in the induction of PGE2 synthesis from arachidonic acid in BEC.

Arachidonic Acid↗
PubMed2003

Silicone gel sheets relieve pain and pruritus with clinical improvement of keloid: possible target of mast cells.

Silicone gel sheet treatment is widely used to treat hypertrophic scars and keloids since it is easily applied and prevents scar pain and itching. We used Cica-Care silicone gel sheets in the conservative treatment of six patients for 24 weeks and recorded pain, itching, redness, and scar elevation every 4 weeks. We also investigated the number of mast cells and Fas antigen expression in the lesional skin (one patient) before and after treatment. The pain and itching clearly decreased after 4 weeks of the silicone gel sheeting and disappeared after 12 weeks. Twelve weeks were required for a reduction in scar redness and elevation. After 24 weeks, a decrease in the number of mast cells and the enhanced expression of Fas antigen by lesional fibroblasts were observed. Thus, silicone gel sheeting is effective and safe, especially with more severe symptoms of pain and itching possibly induced by mediators derived from increased mast cells.

Administration, Topical↗
PubMed2003

Procollagen II C propeptide level in the synovial fluid as a predictor of radiographic progression in early knee osteoarthritis.

OBJECTIVE: To investigate the prognostic value of procollagen type II carboxy-terminal propeptide (PIICP) level in synovial fluid in relation to early tibiofemoral joint osteoarthritis (OA). METHODS: Data were collected on 172 women (age 40 to 59 years) who had knee pain and tibiofemoral joint OA in the early stage. Standing semiflexed knee radiographs were obtained by fluoroscopy at baseline and at four year follow up and a computerised, magnification corrected measurement system was applied to measurement of minimal joint space width in the tibiofemoral compartment. Synovial fluid sampling was performed at baseline and at the four year follow up. Levels of PIICP in the synovial fluid were measured by enzyme immunoassay. The outcome measures were assessed by radiographic joint space narrowing (JSN) in the tibiofemoral joints over four years. Multiple linear regression analyses were used to examine the relation between radiographic JSN and synovial fluid level of PIICP. RESULTS: The number of women available at both baseline and at four year follow up was 110. The average of radiographic JSN over four years was 0.53 mm (range 0.00-2.01). Body mass index showed a slightly positive association with baseline PIICP level. In multiple linear regression analyses adjusted for age and body mass index, radiographic JSN over four years had a direct positive correlation with baseline PIICP level (r=0.395; 95% confidence interval (95% CI) 0.231 to 0.529; p<0.001). CONCLUSION: In a four year prospective study of women, quantification of synovial fluid PIICP was able to predict subsequent radiographic progression in early tibiofemoral joint OA.

Adult↗
PubMed2003

The influence of early ambulation and other factors on headache after lumbar myelography.

In order to determine the influence of early ambulation and other factors on headaches occurring after lumbar myelography we randomised 207 patients (127 men and 80 women) into two groups. Following the investigation, we allowed the 101 patients (65 men and 36 women) in group A to sit or stand freely, while we confined the 106 patients (62 men and 44 women) in group B to bed for 20 hours. The nine patients in group B who could not maintain bed rest were excluded. There was no significant difference between the two groups as regards the prevalence of spinal headache (8.9% in group A v 14.4% in group B). Patients who reported headaches, however, were significantly more likely to be women (18.7%) than men (73%), be younger (mean age 45 years v 56 years), have a higher cerebrospinal pressure before removal of fluid (mean values 172 v 137 mm H2O) and a lower systolic (mean values 120 v 134 mmHg) and diastolic blood pressure. We conclude that, although other factors may be associated with headaches, late ambulation is not effective in preventing spinal headaches after lumbar myelography.

Adult↗
PubMed2003

Somatic mutation of the Caspase-5 gene in human lung cancer.

Using cDNA array-based gene expression profiling, we previously found reduced expression of the Caspase-5 gene in highly metastatic subpopulations of a lung cancer cell line. The Caspase-5 gene contained poly(A) repeats in its coding region, an area that has been reported to be mutated in both endometrial and gastrointestinal tumors displaying evidence of microsatellite instability. In order to determine the contribution of Caspase-5 gene inactivation to lung cancer development and progression, the mutational status of the Caspase-5 poly(A) tract in 30 primary lung cancers with distant metastasis and 30 lung cancer cell lines was determined by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. Three somatic mutations of the Caspase-5 gene were found in two out of 30 lung cancer tissues, although no mutations were found in other genes that also contain small nucleotide repeats, such as hMSH3, hMSH6 and BAX. The results of the present study, combined with our prior cDNA array-based gene expression profiling data, suggest that Caspase-5 might be a suppressor gene of highly metastatic potential in lung cancer.

Base Sequence↗
PubMed2003

Combined effects of vasopressin V2 receptor antagonist and loop diuretic in humans.

AIMS: Patients with edematous diseases are generally treated with diuretics, but frequently present with hyponatremia associated with impaired water excretion. This study investigated the combined effects of vasopressin V2 receptor antagonist OPC-31260, an aquaretic, and furosemide, a saluretic, on free water excretion and serum sodium concentration (PNa). MATERIAL AND METHODS: The study was planned as an open-label, 4-period, 4-treatment, crossover study in 12 healthy subjects using single doses of placebo, furosemide 20 mg (F), OPC-31260 30 mg (O), and furosemide 20 mg plus OPC-31260 30 mg (O+F). RESULTS: OPC-31260 co-administered with furosemide induced an increase in PNa and serum osmolality (F: 281.6 +/- 0.7, O+F: 284.9 +/- 0.7 mOsm/kgH2O) as a result of an additive increase in maximal urine volume (F: 7.7 +/- 1.9, O: 6.8 4 0.5, O+F: 13.2 +/- 1.4 ml/min) with increased electrolyte-free water excretion (F: 0.35 +/- 0.15, O: 5.3 4 0.5, O+F: 4.8 +/- 0.5 ml/min) while maintaining sodium excretion (F: 731 +/- 110, O+F: 1,064 +/- 149 microEq/min). It was suggested that by the co-administration, the resulting decreased generation of free water in Henle's loop was canceled out by a decrease in back--diffusion of free water across the collecting ducts. CONCLUSIONS: The co-administration may be particularly effective in treating edema and hyponatremia in edematous diseases.

Adult↗
PubMed2003

[The evaluation of the complications and its management in 800 patients who underwent the thoracoscopic surgery].

Thoracoscopy has been applied to almost all thoracic surgery as shown (table 1). Besides an opportunity to follow and encounter a trouble during surgery using thoracoscopy, so that it is necessary to become skilled in the prediction and management of complication. Nowadays, there are two options on surgery using thoracoscopy, thoracoscopic surgery (TS) is performed only on in a port and on a mini-thoracotomy with a few ports (video-assisted thoracoscopic surgery: VATS). When changing into emergency or converting into open thoracotomy, a muscle sparing thoracotomy could be available. The symptoms which occurred in the thorax are fundamentally similar during both TS and VATS procedure. However, peculiar dangerous factor existed according to the difference in internal organs, procedures, and diseases. Critical complications during surgery were as follows, i.e., injury of pulmonary vessels and bronchus, tension pneumothorax of the opposite lung and tumor implantation of the chest wall. Basically, standard practice is the most important to avoid an accident and determine whether converting to open thoracotomy should be employed. In the present commentary, we would like to present our experiences and propose regarding management.

Bronchi↗
PubMed2002

Integration of the information from gene expression and metabolic fluxes for the analysis of the regulatory mechanisms in Synechocystis.

Synechocystis was grown under autotrophic, mixotrophic and heterotrophic conditions, and the gene expression patterns at the mRNA and protein levels were measured by using semi-quantitative RT-PCR and two-dimensional electrophoresis (2DE), respectively. Moreover, the intracellular metabolic flux distributions in Synechocystis grown under different trophic conditions were also determined using the carbon isotope labeling technique. By combining the information obtained from the transcript levels, protein abundance and metabolic fluxes, the regulatory mechanisms of some enzymes involved in the central metabolism of Synechocystis during growth in the different culture conditions were analyzed. It was found that depending on the energy source available to cyanobacterial cells, the enzymes required for central metabolism were differently regulated according to different mechanisms. The expression of several genes, such as rbcLS and gap2, was light-regulated transcriptionally, while the gene gnd was regulated in response to an apparent flux requirement but by an unknown mechanism. The expression of other genes was independent of the presence of light. The reactions catalyzed by G6PDH, Fbp, PfkA and FbaA were not regulated through enzyme synthesis but by a change in metabolite concentrations. The enzyme PrK was post-translationally regulated by light, probably through the operation of ferredoxin/thioredoxin system. For the enzyme RubisCO, both transcriptional and post-translational regulation was observed. These findings demonstrate that the information obtained from the analysis of mRNA expression, protein expression, and metabolic flux distribution is necessary to understand the regulatory events in complex cellular networks.

Cyanobacteria↗
PubMed2002

Electronic structure of the trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta).

The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the superconducting gap magnitude and the relative coherence-peak intensity scale linearly with T(c) for various optimally doped materials.

Journal Article↗
PubMed2002

Semiquantitative dynamic computed tomography to predict response to anti-platelet therapy in acute cerebral infarction.

We investigated whether dynamic computed tomography (CT) in patients with acute cerebral infarction could identify patients likely to respond to anti-platelet therapy. Seventy patients underwent semiquantitative dynamic CT within 6 h as well as cerebral angiography. All then received anti-platelet therapy with a thromboxane A2 synthetase inhibitor. Peak value (pv) and time-to-peak (tp) (time-density curves) for the Sylvian fissure were extracted from dynamic CT data and standardizing interpatient data, two indices, PV/TP index and TP index, were prepared following a standard semiquantitative manner. Both PV/TP index and TP index were effective in discriminating between 48 responders (modified Rankin scale (mRS): 0 to 2) and 22 non-responders (mRS: 3 to 5, or death: 6; both P<0.0001). High PV/TP index (>or=0.8) was a strong indicator of favorable response. Most of these patients maintained regional cerebral blood flow (rCBF) via anterograde flow or collaterals, with a TP index 1.1) and non-compensated rCBF. Intermediate PV/TP values could not predict outcome. Dynamic CT prior to therapy can identify patients with acute cerebral infarction who are treatable with anti-platelet therapy alone.

Acute Disease↗
PubMed2002

Intramedullary teratoma of the spine: report of two adult cases.

STUDY DESIGN: Two case reports of intramedullary teratoma in the spinal cord of adults, and a review of the literature. OBJECTIVE: To investigate and describe unusual cases of spinal teratoma using MRI to define features that may be used to avoid misdiagnosis. SETTING: A department of orthopedic surgery in Japan. METHODS: One patient, a 37-year-old woman, was referred because of gait disturbance. She was evaluated by myelography, CT scan with myelography, and MRI. T12 through L1 laminoplasty was performed and the tumor was subtotally removed. The other patient, a 56-year-old man, was referred because of muscle weakness and sensory disturbance. MRI revealed multiple spinal tumors. C4 through C6 laminoplasty and T12 through L2 laminoplasty were performed, and the tumors in these regions were subtotally removed. RESULTS: In Case 1, the postoperative course was excellent, and histological examination of the resected specimen revealed a spinal teratoma consisting of ectodermal and mesodermal elements. In Case 2, the symptoms were resolved after surgery, and ectodermal, mesodermal and endodermal elements were revealed. CONCLUSIONS: Although intramedullary teratomas are very rare in adults, they need to be considered in differential diagnosis.

Adult↗
PubMed2002

Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils.

BACKGROUND: Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. OBJECTIVE: The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. METHODS: RBL-2H3 cells were directly stimulated with anti-rat FcepsilonRI alpha-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human FcepsilonRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). RESULTS: Cross-linking of FcepsilonRI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-FcepsilonRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-FcepsilonRI mAb or by allergen in parallel. CONCLUSION: These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon FcepsilonRI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders.

Adult↗
PubMed2002

Photoprovocation test and immunohistochemical analysis of inducible nitric oxide synthase expression in patients with Sjögren's syndrome associated with photosensitivity.

BACKGROUND: Annular erythema (AE) in Sjögren's syndrome (SS) usually develops on areas of sun-exposed skin and is exacerbated during summer. OBJECTIVES: To evaluate photosensitivity in SS and to investigate the involvement of ultraviolet (UV) radiation in the development of AE in SS. METHODS: Phototesting with UVA and UVB was performed on 14 SS patients, including 10 with primary SS. Clinical and histological features as well as expression of inducible nitric oxide synthase (iNOS) in the evoked skin lesions were compared with those of lupus erythematosus (LE). Eleven SS patients had a history of photosensitive AE (n = 4), papules (n = 3) or other types (n = 4) of lesions on their sun-exposed skin that were induced or aggravated by sunlight exposure. RESULTS: Phototesting induced a prolonged erythematous response (n = 8), infiltrated erythema (IE) (n = 4) and/or papules (n = 3) in 11 of 14 SS patients, including one with primary SS without a history of photosensitivity. Histologically, the induced IE and papules showed coat-sleeve-like or sparse perivascular infiltration of lymphocytes similar to that in primary skin lesions of AE in SS. No epidermal changes characteristic for LE were found except for partial and mild liquefaction degeneration in three cases. In contrast, two cases were indistinguishable from the papular type of polymorphic light eruption in several aspects, including their primary skin lesions and early response to a photoprovocation test. Immunohistochemistry revealed diffuse expression of iNOS throughout the epidermis, which is characteristic for LE, in the three SS patients with minimal liquefaction degeneration, while the remaining seven SS patients examined exhibited no iNOS staining or a normal expression pattern. CONCLUSIONS: Our results indicate that photosensitivity exists in certain primary SS patients, and that UV is critical to the development of AE in SS, probably through a pathological mechanism distinct from that in LE.

Adult↗