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Biomedical subjects

H Iwata

Publications and source records attributed to H Iwata.

At least 91 records · Page 5Linked to original sources
PubMed2001

Osteonecrosis of the femoral head after allogeneic bone marrow transplantation.

A comparative retrospective analysis of 100 consecutive patients after bone marrow transplantation was performed with magnetic resonance imaging in addition to plain radiography for the development of osteonecrosis of the femoral head. The incidence and risk factors for osteonecrosis of the femoral head were identified, comparing various parameters concerning bone marrow transplantation between the groups with and without evidence of osteonecrosis. Nineteen (19%) of 100 patients had osteonecrosis of the femoral head develop. Four factors were found to be statistically significantly different between patients who had osteonecrosis develop and those who did not: younger age at the time of bone marrow transplantation, chronic graft-versus-host disease, cumulative dose of steroid, and intravenous pulse therapy with methylprednisolone. It was concluded that a low rate of complications and low dose steroid administration would reduce the incidence of osteonecrosis after bone marrow transplantation.

Adolescent↗
PubMed2001

Prediction of osteonecrosis by magnetic resonance imaging after femoral neck fractures.

Thirty-one patients undergoing internal fixation for femoral neck fractures who were examined by magnetic resonance imaging at 2, 6, and 12 months after surgery and who could be followed up more than 2 years were enrolled in the current study. The items investigated were timing of the appearance of the band image on T1 weighted images, magnetic resonance imaging classification, and plain radiographs. Band images were observed 2 months after surgery in eight patients and 6 months in 12 patients (39% of all patients). According to the location and extent of the band image on magnetic resonance imaging, one patient was classified in the B1 Group (lateral type), four patients in the B2 Group (surface type), three patients in the B3 Group (intermediate type), and four patients in the B4 Group (extended type). Band images appeared in all patients in the B4 Group 6 months after surgery. Femoral heads of the patients in the B3 and B4 Groups by magnetic resonance imaging classification all were collapsed. On plain radiographs, osteonecrosis of the femoral head could be diagnosed in eight patients between 11 and 24 months after injury. The interval giving the greatest sensitivity, specificity, and accuracy of the diagnosis of osteonecrosis of the femoral head by magnetic resonance imaging was 6 months after surgery.

Adult↗
PubMed2001

Successful subcutaneous pancreatic islet transplantation using an angiogenic growth factor-releasing device.

INTRODUCTION: Although the subcutaneous tissue is considered as an attractive site for pancreatic islet transplantation, the success rate has been extremely low. AIMS: To use basic fibroblast growth factor (bFGF) to induce neovascularization and sufficient blood flow around the space formed for grafted islets in the subcutaneous tissue to improve the islet survival. METHODOLOGY: In the experimental group, two bFGF-releasing devices were implanted bilaterally into the subcutaneous tissue (back) of diabetic Lewis rats. One week after implantation, in the same site, isolated rat islets were syngeneically transplanted after the removal of the devices. In the control group, two devices without bFGF were implanted before subcutaneous islet transplantation of the same number of islets. RESULTS: One week after the implantation of the bFGF-releasing devices in the experimental animals, the devices induced angiogenesis by slow release of bFGF. After transplantation of islets, the neovascularized recipient rats showed significant decreases in nonfasting blood glucose concentration and maintained normoglycemia for more than 3 months. However, in the control group, all rats failed to achieve normoglycemia after transplantation in the absence of neovascularization. CONCLUSION: This study provides evidence that the subcutaneous tissue is a promising site for pancreatic islet transplantation, which suggests the acceptability of this treatment for diabetic recipients.

Animals↗
PubMed2001

Derivation of pharmacokinetics equations for quantitative evaluation of bioartificial liver functions.

A bioartificial liver (BAL) is an extracorporeal medical device incorporating living hepatocytes in a cartridge. A variety of BALs have been developed and new devices are being introduced. Some of them have been clinically applied and from the results obtained they are claimed to be useful devices for assisting the liver functions of patients. However, there is still uncertainty as to their efficacy and their limitations are not clear. It is important to establish methods to quantitatively evaluate the metabolic and synthetic functions of BAL. In this paper, we derive simple equations for the quantitative evaluation of BAL functions on the basis of pharmacokinetics. Pharmacokinetics was originally developed to understand the processes of absorption, distribution, and elimination of administered drugs. Metabolic functions of the natural liver have been analyzed using pharmacokinetics and values of the useful parameters, clearance (CL) and intrinsic clearance (CLint), have been reported. The metabolic functions of the BAL expressed using values of CL and CLint are easily compared with those of the normal human liver. We believe that our method provides a useful basis for estimating the clinical effectiveness of BAL.

Bioartificial Organs↗
PubMed2001

An approach to constructing three-dimensional tissue.

The authors propose an approach to constructing three-dimensional tissue with capillaries using cellulose hollow fibers. Fibronectin (FN) was immobilized on hollow fibers to assure cell attachment. Bovine coronary artery smooth muscle cells (BCASMC) and L cells were seeded on FN-immobilized fibers and cultured for an extended period of time. The cells proliferated and formed multicellular layers on the fibers. The hollow fibers were removed by enzymatic digestion using cellulase. The cellulase treatment did not damage L cells, although some cells fell off from the fibers. On the other hand, no deterioration was observed in the BCASMC aggregate structure. The BCASMC aggregates maintained several lumens after removal of the hollow fibers by cellulase digestion. The authors believe that their approach offers a useful method to tissue engineering in preparation of three-dimensional tissue structure.

Animals↗
PubMed2001

Effects of different durations of exercise on macrophage functions in mice.

The effects of differing durations of daily exercise on macrophage functions in mice were studied. Male ICR mice aged 4 wk were divided into five groups: a nonexercise group (control) and four exercise groups with differing daily exercise durations of 15--120 min (Exr groups). The exercise applied was 5 days/wk treadmill running at 13 m/min for 12 wk. The potentiation of the phagocytosis function of the reticuloendothelial system and the glucose consumption of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly higher than those in the control group. Superoxide anion production of peritoneal macrophages in both the absence and the presence of phorbol 12-myristate 13-acetate in the Exr 60 and 120 groups was significantly higher than that in the control group. The acid phosphatase and beta-glucuronidase activities of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly increased. These results suggest that treadmill running exercise for at least 30 min/day (30--120 min) effectively enhances macrophage functions in mice. These data provide preliminary evidence indicating that chronic exercise-induced increases in phagocytic activity exhibit a dose-dependent relationship with exercise duration.

Acid Phosphatase↗
PubMed2001

Interaction of poly(2-acrylamido 2-methylpropane sulfonate)-grafted polystyrene beads with cationic complement proteins.

Influence of various biomaterials on the complement system in serum has been intensively studied by many research groups, since activation of the complement pathway in vivo has been known to give rise to some pathological conditions, such as inflammation and anaphylaxis. Much effort has been devoted to develop new materials that do not activate or deteriorate the complement system. The present work is aimed at revealing the mode of reactions of anionic poly(2-acrylamido 2-methylpropane sulfonate) grafted on polystyrene bead (PAMPS-g-bead) with serum complement. Complement activity assay, determination of complement proteins levels, and immunoblot analysis were carried out for sera pretreated with PAMPS-g-beads. The results clearly showed that, when PAMPS-g-beads were incubated with serum, those beads adsorbed several complement proteins, i.e. C1q, factor D, factor P, C6, and C8, but the generation of activation fragments of complement components was not observed. Especially, factor D was most effectively removed from serum, resulting in potential inhibition of the alternative pathway. A larger amount of PAMPS-g-beads was needed to decrease the serum CH50 level. That may be caused by removal of C6. Although some polyanions, such as dextran sulfate, were reported to activate the complement system, the obtained results indicate that the PAMPS-g-bead is not an activator of the complement pathway, but acts as an adsorbent of complement components. One possible clinical application of the PAMPS-g-beads is adsorption of serum factor D by extracorporeal treatment of patients with renal failure with a high level of factor D, because the increased quantity of factor D in serum may cause consistent activation of the alternative pathway.

Biocompatible Materials↗
PubMed2001

Caffeoyl, coumaroyl, galloyl, and hexahydroxydiphenoyl glucoses from Balanophora japonica.

Eighteen new and sixteen known acyl glucoses having caffeoyl, coumaroyl, galloyl, and hexahydroxydiphenoyl groups were isolated from a medicinal parasitic plant, Balanophora japonica. Their structures were determined by spectroscopic and chemical methods. Caffeoyl ellagitannins, which have been rarely found in nature, were major phenolic constituents of this plant, and this is the first report of the isolation of ellagitannins from Balanophoraceae.

Biphenyl Compounds↗
PubMed2001

Nine cases of granular cell tumors in B6C3F1 mice.

The histological characteristics of 9 cases of granular cell tumors (GCTs) observed in B6C3F1 mice were examined to determine their cellular origin. Seven of the 9 cases were found in the uterus and other 2 cases were in the subcutaneous tissue. Tumor cells had abundant granules in the cytoplasm which were stained with PAS and were resistant to diastase treatment. Ultrastructurally, the granules were identified as lysosomes. The cell surface had cytoplasmic processus showing interdigitation with adjacent cells. A character feature of the tumor cells was the presence of a desmosome-like structure on their cell surface but no basal lamina was demonstrated. Although GCTs have been considered to be derived from Schwann cells on the basis of their ultrastructural features and S-100 protein-immunopositive findings, the absence of basal lamina in the present cases may raise a controversy as to their origin.

Animals↗
PubMed2001

The complete nucleotide sequences of L3 and S7 segments of Ibaraki virus encoding for the major inner capsid proteins, VP3 and VP7.

The complete nucleotide sequences of the genes encoding two of the major inner capsid proteins of Ibaraki virus (IBAV), belonging to epizootic hemorrhagic disease virus serotype 2 (EHDV-2) were determined. The L3 RNA segment is 2768 nucleotides in length which encodes VP3 polypeptides of 899 amino acid residues (M.W. 103 kDa). The S7 RNA segment, which encodes the VP7 core protein, is 1162 nucleotides in length and encodes 349 amino acids (M.W. 38 kDa). These RNA segments had the characteristic consensus motifs of Orbivirus RNA segments in termini, namely 5'-GUUAAA... and ...ACUUAC-3'. The comparison of the IBAV L3 and S7 sequences with those of other two EHDV-2 isolates revealed the higher homologies of 93% and 92% against EHDV-2 Australia isolate (EHDV-2AUS) and lower homologies of 80% and 81% against EHDV-2 North America isolate, respectively. The phylogenetic analysis based on L3 and S7 genes also indicated close relationships between IBAV and EHDV-2AUS.

Amino Acid Sequence↗
PubMed2001

Tumor necrosis factor alpha induces expression of genes for matrix degradation in human chondrocyte-like HCS-2/8 cells through activation of NF-kappaB: abrogation of the tumor necrosis factor alpha effect by proteasome inhibitors.

Tumor necrosis factor alpha (TNF-alpha) has been suggested to induce chondrocytic chondrolysis in both inflammatory and degenerative joint diseases. However, its intracellular signaling pathway leading to the chondrolysis has not been studied in detail. Thus, we investigated whether TNF-alpha activates a transcription factor nuclear factor kappaB (NF-kappaB) in human chondrocyte-like cells (HCS-2/8) and induces the expression of genes involved in the degradation of cartilage matrix. Treatment of the cells with TNF-alpha markedly increased the levels of matrix metalloproteinase 1 (MMP-1), MMP-3, intercellular adhesion molecule 1 (ICAM-1), and cyclo-oxygenase 2 (COX-2) messenger RNAs (mRNAs). The increase in the mRNAs was associated with the activation of p65/p50 heterodimer NF-kappaB. IkappaB-alpha and IkappaB-beta, cytoplasmic molecules preventing the nuclear translocation of NF-kappaB, were degraded rapidly by TNF-alpha followed by their synthesis to the basal level. Treatment with proteasome inhibitors inhibited the degradation of both IkappaB-alpha and IkappaB-beta and prevented the TNF-alpha-dependent nuclear translocation of p65. Furthermore, the inhibitors completely prevented the TNF-alpha-dependent induction of MMP-1, MMP-3, ICAM-1, and COX-2 mRNAs. Thus, it is shown that the activation of p65/p50 NF-kappaB by TNF-alpha plays a cardinal role in inducing the expression of MMP-1, MMP-3, ICAM-1, and COX-2 genes, which are involved in matrix degradation and inflammatory reaction in chondrocytes, leading to chondrocytic chondrolysis.

Blotting, Western↗
PubMed2001

Endotracheal/endobronchial metastases : clinicopathologic study with special reference to developmental modes.

BACKGROUND: Endotracheal/endobronchial metastases (EEMs) from nonpulmonary neoplasms are rare. However, their definition and developmental modes have not yet been fully elucidated. METHODS: EEMs were defined as documented nonpulmonary neoplasms metastatic to the subsegmental or more proximal central bronchus, in a bronchoscopically visible range. The clinical and pathologic features of 16 cases were reviewed, with special emphasis on the developmental modes based on five criteria: location in the tracheobronchial tree, number of lesions, laterality of lesions, depth of lesions, and relationship with the associated bronchus. RESULTS: The developmental modes were proposed on the basis of the above five criteria as follows: type I, direct metastasis to the bronchus; type II, bronchial invasion by a parenchymal lesion; type III, bronchial invasion by mediastinal or hilar lymph node metastasis; and type IV, peripheral lesions extended along the proximal bronchus. Primary tumors included colorectal in six patients, breast in three patients, uterus in two patients, osteosarcoma of the bone in two patients, and maxillary, larynx, and parotid carcinoma in one patient each, respectively. The mean recurrence interval was 65.3 months. The developmental modes were as follows: type I, five patients; type II, one patient; type III, four patients; and type IV, nine patients. Three patients underwent surgical resection. One patient has remained well for 5 years after operation. Median and mean survival times were 9 months and 15.5 months, respectively. CONCLUSION: The mean recurrence interval was long at 65.3 months, but the mean survival time was short at 15.5 months. Type I accounted for only 5 of 16 patients. Type II was found in only one patient. It is thought that this type is a rare form. Type IV affected nine patients. Treatment plans must be individualized, because in some cases, long-term survival can be expected.

Bone Neoplasms↗
PubMed2001

Concentration and localization of YKL-40 in hip joint diseases.

OBJECTIVE: YKL-40 is a major secretory protein from human chondrocytes and synovial fibroblasts. We evaluated the concentrations and localization of YKL-40 in hip joint diseases, and analyzed the possibility of YKL-40 as a new inflammatory joint marker. METHODS: The concentration of YKL-40 in synovial fluid (SF) was measured by a sandwich-type ELISA. SF samples were collected from 19 hips with osteoarthritis (OA) of the hip joint, 21 hips with osteonecrosis of the femoral head (ONFH), and 5 hips with failed total hip arthroplasty (failed THA). In all cases of failed THA, cartilage tissue in hip joints was removed completely during the previous THA. The localization of YKL-40 was determined through immunohistochemical analysis using a specific antibody. RESULTS: The mean SF concentration of YKL-40 was significantly higher in ONFH and failed THA than in OA. Comparison by OA grade was not significantly different. In staging of ONFH, Ficat stage III with collapsed femoral head showed significantly higher YKL-40 concentrations than the other stages. Immunohistochemical studies showed that YKL-40 was localized in chondrocytes in the superficial and middle layers of the cartilage. In the synovium, YKL-40 was localized in fibroblasts and macrophages. CONCLUSION: YKL-40 reflects the degree of inflammation rather than cartilage metabolism. YKL-40 may be a useful inflammatory marker of hip joint diseases.

Adipokines↗
PubMed2001

Negative correlation between plasma thyroid hormone levels and chlorinated hydrocarbon levels accumulated in seals from the coast of Hokkaido, Japan.

Chlorinated hydrocarbon (CHC) levels in the blubber of larga seals (Phoca largha) and ribbon seals (Phoca fasciata) collected from the coastal waters of Hokkaido, Japan, were determined in order to assess the hormonal effects of CHC exposure in free-ranging pinnipeds. Plasma thyroid hormone levels, including total thyroxine (T4), free thyroxine (free T4), total triiodothyronine (T3), and free triiodothyronine (free T3), were also measured. Higher concentrations of polychlorinated biphenyl congeners (PCBs), dichlorodiphenyltrichloroethane and its metabolites, and chlordane compounds were found in the range of 380 to 2,600 ng/g, 350 to 2,600 ng/g, and 120 to 760 ng/g on a wet-weight basis, respectively. Spearman rank correlation analyses showed that in larga seals, plasma total T3 and free T3 levels negatively correlated with levels of all the CHCs analyzed, although there was no such correlation between total or free T4 levels and CHC concentrations. In ribbon seals, total T3 levels significantly decreased with an increase of di-ortho PCB (PCB170 and 180) residues. These findings indicated that the plasma T3 deficiency could be associated with some CHC exposure in larga and ribbon seals and that the responses of plasma thyroid hormones may be useful biomarkers for CHC exposure in ribbon seals.

Animals↗
PubMed2001

[Primary squamous cell carcinoma of the prostate forming a rectourethral fistula: a case report].

Eleven cases of squamous cell carcinoma of the prostate have been previously reported in the Japanese medical literature. Patients with this type of carcinoma have dismal prognoses. Herein, we report a case in a 61-year-old man who was admitted to our hospital and whose chief complaints were dysuria and high fever. Pyuria, bacteriuria, and the results of a digital rectal examination suggested acute prostatitis. Despite the administration of antibiotics, the dysuria did not improve. A transrectal needle biopsy was performed, and histology of the tissue showed squamous cell carcinoma. After chemotherapy using methotrexate, pirarubicin, and cisplatin, total pelvic excentration was performed. At 12 months after the operation, the patient is alive with no evidence of the disease.

Antigens, Neoplasm↗
PubMed2001

[A case of fibrous pseudotumor in the scrotum].

A 65-year-old man presented with a complaint of the swelling of his right scrotum. Ultrasonogram indicated a tumor in the right scrotum, but it was not apparent whether the tumor arose from the right testis or not. Right high orchiectomy was performed due to the suspicion of malignancy. The tumor arose from the right epididymis and spermatic cord. Histological examination revealed that the tumor was a fibrous pseudotumor in the scrotum.

Aged↗