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Biomedical subjects

Osamu Ishida

Publications and source records attributed to Osamu Ishida.

At least 37 records · Page 2Linked to original sources
PubMed2004

Bone formation using novel interconnected porous calcium hydroxyapatite ceramic hybridized with cultured marrow stromal stem cells derived from Green rat.

The clinical use of cultured marrow stromal stem cells (MSCs) has recently attracted attention in the field of tissue engineering. For the clinical use of the MSCs, a prominent scaffold is needed. A scaffold hybridized with MSCs is transformed into a "bioactive bone substitute," and this provides good osteoconduction. In this study, a novel calcium hydroxyapatite ceramic with an interconnected porous structure (IP-CHA) was used as a scaffold. MSCs were harvested from Green rats containing Green Fluorescent Protein (GFP), and then these hybrids were implanted into the tibias of Sprague-Dawley rats. The purposes of this study were to examine the osteogenic ability of these hybrids without coculture, and to evaluate whether the resulting bone formation originated from the grafted MSCs or the recipient's cells. The hybridized group showed excellent bone formation compared with the IP-CHA-only implant group. Observation of the implanted MSCs revealed that they survived 8 weeks after surgery, and differentiated into osteoblast-like cells, thus providing bone formation. This implantation of the MSCs/IP-CHA composite provides excellent osteoconduction, and is expected to have extensive clinical applications.

Animals↗
PubMed2004

Basal jawed vertebrate phylogeny inferred from multiple nuclear DNA-coded genes.

BACKGROUND: Phylogenetic analyses of jawed vertebrates based on mitochondrial sequences often result in confusing inferences which are obviously inconsistent with generally accepted trees. In particular, in a hypothesis by Rasmussen and Arnason based on mitochondrial trees, cartilaginous fishes have a terminal position in a paraphyletic cluster of bony fishes. No previous analysis based on nuclear DNA-coded genes could significantly reject the mitochondrial trees of jawed vertebrates. RESULTS: We have cloned and sequenced seven nuclear DNA-coded genes from 13 vertebrate species. These sequences, together with sequences available from databases including 13 jawed vertebrates from eight major groups (cartilaginous fishes, bichir, chondrosteans, gar, bowfin, teleost fishes, lungfishes and tetrapods) and an outgroup (a cyclostome and a lancelet), have been subjected to phylogenetic analyses based on the maximum likelihood method. CONCLUSION: Cartilaginous fishes have been inferred to be basal to other jawed vertebrates, which is consistent with the generally accepted view. The minimum log-likelihood difference between the maximum likelihood tree and trees not supporting the basal position of cartilaginous fishes is 18.3 +/- 13.1. The hypothesis by Rasmussen and Arnason has been significantly rejected with the minimum log-likelihood difference of 123 +/- 23.3. Our tree has also shown that living holosteans, comprising bowfin and gar, form a monophyletic group which is the sister group to teleost fishes. This is consistent with a formerly prevalent view of vertebrate classification, although inconsistent with both of the current morphology-based and mitochondrial sequence-based trees. Furthermore, the bichir has been shown to be the basal ray-finned fish. Tetrapods and lungfish have formed a monophyletic cluster in the tree inferred from the concatenated alignment, being consistent with the currently prevalent view. It also remains possible that tetrapods are more closely related to ray-finned fishes than to lungfishes.

Animals↗
PubMed2004

Wide-range visualization of compound nerve action magnetic fields in the human median and ulnar nerves from the forearm to Erb's point.

We successfully visualized the compound nerve action magnetic fields (CAFs) in the human median and ulnar nerves from the forearm to Erb's point. To observe the CAFs, we used a superconducting quantum interference device gradiometer system that was developed for human peripheral nerves. The CAFs were visualized as a quadrupole pattern consisting of leading and trailing dipoles. The CAFs propagated along the anatomical pathway and extended longitudinally in the proximal segment. The most reasonable explanation is that the peak separation in the trailing dipole appeared when the leading dipole reached the proximal segment after stimulation of the median nerve at the wrist. A temporal dispersion of the CAFs was suggested to be visualized.

Adult↗
PubMed2004

Bone lengthening for congenital differences of the hands and digits in children.

PURPOSE: We investigated the growth of bones after lengthening to evaluate the effectiveness and usefulness of bone lengthening in congenital hand deficiencies. METHODS: Bone lengthening was performed to treat congenital hand deficiencies including hypoplastic thumb, hypoplasia of the small finger, cleft hand, metacarpal synostosis, brachymetacarpia, symbrachydactyly, and amniotic band syndrome. A total of 15 patients (1-13 years old) underwent lengthening of 23 bones. The average of distraction was 10 mm. The mean follow-up period was 59 months. The length of the bones at follow-up evaluation was measured and then compared with the length of the bones immediately after lengthening. The bone growth after lengthening, the percentage of growth after lengthening, and the growth rate were compared among diagnostic groups. RESULTS: In the cases involving older patients the bone length changed little and the growth plates of these patients closed naturally soon after lengthening. In contrast, in the cases in which the patients were younger than 7 years old the lengthened bones grew continuously. The amount of bone growth was different for each disease in the younger patients. In patients with amniotic band syndrome the lengthened bones grew at the same rate as the bones in the hand. Other diagnoses such as symbrachydactyly had a different growth pattern in the hand. CONCLUSIONS: We conclude that bone lengthening is a reliable method for the correction of congenital differences of the hand. The indications for this procedure must be determined while considering the relationship between the specific disease and subsequent bone growth.

Adolescent↗
PubMed2004

Acceleration of surgical angiogenesis in necrotic bone with a single injection of fibroblast growth factor-2 (FGF-2).

The aim of this study was to accelerate angiogenesis in necrotic bone by combining vascular bundle implantation and fibroblast growth factor-2 (FGF-2) administration. Twenty-four Japanese white rabbits were evaluated in this study. A portion of a rabbit iliac crest bone was removed as a free bone graft and frozen in liquid nitrogen to ensure complete cellular necrosis. A narrow hole was created in the bone and the graft was placed in the proximal thigh. In group 1, FGF-2 was injected into the hole at a single dose of 100 microg, and the saphenous artery and its venae comitantes were passed through the hole of the bone. In group 2, injection of saline into the hole and the vascular bundle implantation was used as a control. Neovascularization around the vessel was evaluated at weeks 1 and 2 after surgery. Neovascularization was observed along the implanted vascular bundle in both groups. At both 1 and 2 weeks after surgery, the vessel density of group 1 was significantly higher than that of group 2. The average length of newly formed vessels of group 1 was also significantly longer than that of group 2 at both 1 and 2 weeks after surgery. Both the vessel density and length were greater in week 2 animals than week 1. A local single injection of FGF-2 improved surgical angiogenesis in necrotic bone in this study. As FGF-2 is recognized as a potent mitogen for a variety of mesenchymal cells, the combination of vascular bundle implantation and FGF-2 administration may contribute to the treatment of ischemic osteonecrosis.

Animals↗
PubMed2004

Interposed autologous nerve segment stimulates nerve regeneration in peripheral nerve allografts in a rat model.

The ability of autologous nerve segments interposed between allografts, to increase the total nerve-gap distance, was studied. Sciatic nerve allografts were carried out in a rat model. A 15-mm nerve gap was repaired with a 25-mm nerve graft (interposed group: allo-auto-allograft; control group: allo-allo-allograft). Cyclosporin was given for 12 weeks. Nerve regeneration was evaluated using the weight of the anterior tibial muscle and histologic, morphometric and immunohistochemical analyses at 12, 13, 14, 15, 16, 20, and 24 weeks. Nerve regeneration in the interposed group was statistically significantly better than that in the control group. The authors concluded that a nerve allograft with interposed autograft may enhance nerve regeneration in this model, because of the migration of host-derived Schwann cells into the graft from not only the proximal and distal host nerve stumps, but also the interposed autograft.

Animals↗
PubMed2004

Corrective valgus osteotomy after free vascularized fibula transfer for the treatment of osteomyelitis at the neck of the femur: case report.

Reconstruction using a free vascularized fibula was performed on a long bony defect after osteomyelitis of the proximal femur. For this type of bone defect, a double-barrel fibular graft is recommended. The authors used this procedure for a 58-year-old male who had osteomyelitis of the left proximal femur. As osteotomy through a transplanted fibula can be safely performed, abduction osteotomy should be considered when coxa vara remains after reconstruction with a free vascularized fibula transfer.

Femur Neck↗
PubMed2004

Effects of transforming growth factor-beta 1 on the early stages of healing of the Achilles tendon in a rat model.

We studied the effects of transforming growth factor-beta 1 (TGF-beta 1) on the genetic expression of procollagen type I and III and its effects on structural properties in the early stages of healing in rat Achilles tendon. The Achilles tendons in 90 rats were transsected and repaired immediately. TGF-beta 1 dissolved in phosphate-buffered saline was injected locally at the repair site using two different doses, and outcomes in both groups were compared to that in the control group given phosphate-buffered saline only. Five animals in each group were killed at one, two, and four weeks postoperatively, and the healing tendon was evaluated. A dose-dependent increase in the expression of procollagen type I and III mRNA was found one week postoperatively. The failure load and stiffness of the healing tendon were increased by TGF-beta 1 at two and four weeks.

Achilles Tendon↗
PubMed2004

Anterior interosseous nerve palsy after reduction and percutaneous pinning of open fractures of the radius and ulna.

We report a case of an anterior interosseous nerve palsy after closed reduction and percutaneous pinning of open fractures of the radius and ulna in an adult. Operative findings showed that the anterior interosseous nerve was trapped between the distal and proximal part of the fractured radius. Treatment by neurorrhaphy gave a satisfactory result.

Fracture Fixation, Intramedullary↗
PubMed2004

Cervical angina caused by atlantoaxial instability.

Cervical angina is defined as a paroxysmal precordialgia that resembles true cardiac angina caused by cervical spondylosis. Cervical angina most commonly results from compression of the C7 ventral root. We present here a case of cervical angina caused by atlantoaxial instability. This case had marked atlantoaxial instability but no flexibility of the middle to lower levels of the cervical spine. Although there was mild C7 root compression on the radiologic findings, the chest pain was induced by neck motion, and the precordialgia disappeared after posterior atlantoaxial fusion without C7 root decompression. Therefore, we diagnosed this case as cervical angina caused by spinal cord compression at the C1-C2 level. It was speculated that a perturbation of the sympathetic nervous system or a hypofunction of the pain suppression pathway in the posterior horn of the spinal cord caused the pectoralgia. Although cervical angina is a rare disease, physicians should be aware of it; if there are no abnormal findings on cardiac examinations for angina pectoris, they should examine the cervical spine. Cervical angina due to atlantoaxial instability is one of the differential diagnoses of precordialgia.

Afferent Pathways↗
PubMed2003

Transplanted neuronal progenitor cells in a peripheral nerve gap promote nerve repair.

A basic experiment of peripheral nerve regeneration using neuronal progenitor cells embedded in collagen gel was performed in a rat sciatic nerve defect. First, when neuronal progenitor cells derived from the fetal rat hippocampus were cultured in atelocollagen-containing medium, neurospheres positive for anti-nestin antibody were confirmed after 8 days. These cells differentiated into astrocytes positive for anti-glial fibrillary acidic protein (GFAP) antibody, oligodendrocytes positive for anti-galactocerebroside (GalC) antibody and neurons positive for anti-neurofilament 200 (NF200) antibody, and they were capable of extending axons. They also differentiated into Schwann-like supportive cells positive for anti-s100 and anti-p75 antibody. Next, a 15-mm defect was prepared in the sciatic nerve of mature rats, and the nerve was bridged with a silicone tube filled with neuronal progenitor cells (1 x 10(5)) embedded in collagen gel. The transplanted neuronal progenitor cells were labeled in advance with 5-bromo-2-deoxyuridine (BrdU). When the regenerated tissue was examined 6 weeks and 10 weeks after grafting, the number and diameter of myelinated fibers were significantly increased compared with a control tube without neuronal progenitor cells. Action potentials were detected in the regenerated nerve. Also, cells positive for both anti-BrdU antibody and anti-S100 or anti-p75 antibody were observed in the regenerated tissue, and part of the grafted neural stem cells were considered to have differentiated into Schwann cell-like supportive cells. From these results neuronal progenitor cells derived from the fetal rat hippocampus are considered to retain their proliferative and differentiating abilities in collagen gel, and when transplanted to a site of peripheral nerve defect, part of them differentiate into supportive cells and they contributed to promotion of axonal regeneration.

Animals↗
PubMed2003

A morphological study of the scaphoid using a mathematical technique and comparative study of the three-dimensional measurements of the scaphoid.

To guide reconstruction of scaphoid non-union, we attempted to create full-scale models of the scaphoid by three-dimensional computed tomography (3D CT) of the healthy side. In this study, we obtained 3D scans of 51 cadaveric hands and studied the difference in morphology between genders and between the left and right sides. The major axis length on a fixed plane and Fourier transformation curve were examined. Ten scaphoid images were also obtained with 3D CT before and after removal from the cadaveric hands. Our findings suggest good correlation between models produced using 3D CT images of the scaphoid alone, and this could serve as an accurate model if the magnification is corrected using the regression line. However, the model using 3D CT images of the intact wrist joint has a large margin of error and its use will not be practical.

Aged↗
PubMed2003

Triple immune suppression increases short-term survival of porcine fetal retinal pigment epithelium xenografts.

PURPOSE: To determine the effect of triple drug immune suppression on RPE xenograft survival in the fetal pig after transplantation into the albino rabbit subretinal space. METHODS: Primary RPE microaggregates (approximately 40,000 RPE cells) were injected into the subretinal space of 24 albino rabbits, with half the rabbits maintained on triple systemic immune suppression. RPE survival was estimated with a DNA probe (porcine DNA repeat element; PRE) against a porcine-specific repetitive chromosomal marker or a RAM-11 antibody against rabbit macrophages. RESULTS: Numerous pigmented cells were visible in the subretinal space at all time points, but most pigment-containing cells 4 weeks or more after surgery were RAM-11 positive and PRE negative. The number of PRE-positive cells in the immune-suppressed group (4193 +/- 2461, 1184 +/- 1502, and 541 +/- 324 at 4, 8, and 12 weeks, respectively) was greater than in immune-competent control animals (292 +/- 506, 193 +/- 173, and 111 +/- 96), but the difference was only statistically significant at 4 weeks. The time-dependent decrease in PRE-positive cells was more pronounced in immune-suppressed animals. Image analysis performed on serial fundus photographs and fluorescein angiograms did not detect any difference in the appearance of the grafts in immune-suppressed versus immune-competent animals. CONCLUSIONS: Systemic immune suppression increased the 4-week survival of porcine RPE xenografts in the albino rabbit subretinal space, but there was poor survival in immune-suppressed and -competent animals 12 weeks after surgery. Many pigment-containing cells 4 or more weeks after surgery were PRE negative, indicating that they are of host origin.

Animals↗
PubMed2003

[Four cases of gastric cancer with multiple hepatic metastases successfully treated with TS-1 in combination with low-dose cisplatinum].

We treated five cases for multiple hepatic metastases from gastric cancer with a novel combination of TS-1 and low-dose cisplatinum (CDDP). TS-1 was orally administered at 100 mg/body/day every day or only on weekdays, and 10 mg of CDDP was infused once or twice a week. The efficacy was evaluated by body CT after the treatment. The CT showed more than a 60% reduction of hepatic tumors in four patients. The tumor markers, CEA and CA19-9, were reduced to 10%. The response rate was 80%. Adverse reactions of grade 1 anemia were observed in two patients and grade 1 leucopenia in one patient. The liver function normalized in one patient. The hemoglobin level was increased from 6.8 g/dl to 11.8 g/dl in one patient. In conclusion, this combined chemotherapy of TS-1 and low-dose CDDP proved useful for advanced gastric cancer patients with multiple hepatic metastases, in view of its therapeutic efficacy, patients' quality of life and low toxicity.

Administration, Oral↗
PubMed2002

Intracellular targeting therapy of cisplatin-encapsulated transferrin-polyethylene glycol liposome on peritoneal dissemination of gastric cancer.

Peritoneal dissemination in gastric cancer is a common fatal clinical condition with few effective therapies available. We studied the therapeutic effect of a tumor-targeting drug delivery system that uses cisplatin-encapsulated and Tf-conjugated PEG liposomes (Tf-PEG liposomes) in nude mice with peritoneal dissemination of human gastric cancer cells. Small unilamellar Tf-PEG, PEG or DSPC/CH liposomes (bare liposomes) encapsulating cisplatin were prepared by reverse-phase evaporation followed by extrusion. Electron microscopic studies revealed that Tf-PEG liposomes were internalized into tumor cells by receptor-mediated endocytosis. To examine the biodistribution of each liposome and cisplatin level, nude mice were inoculated i.p. with 10(7) MKN45P human gastric tumor cells. On the fourth day after tumor inoculation, (3)H-CHE-labeled and cisplatin-encapsulated Tf-PEG, PEG or bare liposome were inoculated i.p. The Tf-PEG liposome-administered group maintained high liposome and cisplatin levels in ascites and showed a prolonged residence time in the peripheral circulation. Uptake of Tf-PEG liposomes into the liver and spleen was significantly lower than that of bare liposomes. Uptake of Tf-PEG liposomes in disseminated tumor cells of ascites and the greater omentum was significantly higher than that of PEG or bare liposomes and a significant increase in cisplatin levels was observed in these tumor cells. Mice receiving Tf-PEG liposomes 1 and 4 days after the day of tumor inoculation showed significantly higher survival rates compared with those receiving PEG liposomes without Tf, bare liposomes or free cisplatin solution. These results suggest that cisplatin-encapsulated Tf-PEG liposomes may be useful as a new intracellular targeting carrier for treatment of gastric cancer with peritoneal dissemination.

Animals↗
PubMed2002

Microvascular toe transfer for cleft-foot plasty: eight-year follow-up.

No exact equivalent procedure has been developed for cleft-foot plasty. In the case of a four-year-old boy, the plasty was achieved by using microvascular toe transfer from a contralateral side that was amputated. Eight years postoperatively, the longitudinal growth of the grafted toe is symmetric, compared to the recipient toes, and the appearance of the treated foot is quite natural. The patient can run with a prosthesis on the amputated leg. It is suggested that utilization of parts from a useless extremity is important to reconstruct the other extremity.

Amputation, Surgical↗
PubMed2002

Installing magnetic keepers using LASER welding.

Magnetic overdenture attachments can provide useful denture retention. A technique is proposed that involves installing the magnetic keeper in the overdenture abutment coping using laser welding. Compared with the conventional cast-to technique, the new technique provides a suitable contour to the abutment coping with the magnetic keeper and ensures proper mounting in the abutment coping, installing the magnetic keeper easily and effectively.

Dental Abutments↗