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Biomedical subjects

M Osada

Publications and source records attributed to M Osada.

At least 73 records · Page 4Linked to original sources
PubMed1997

The influence of different types of hard palate closure in two-stage palatoplasty upon palatal growth: dental cast analysis.

We investigated the influence of different types of hard palate closure in two-stage palatoplasty. In 12 cases the lip and soft palate were closed at the age of 3 to 7 months; these 12 were then divided into two groups. The hard palate was closed at the age of 1 year 5-11 months by the vomer flap with skin graft in the vomer flap (VF) Group (Osada's two-stage palatoplasty), and by push-back procedure of the mucoperiosteal flap in the push-back (PB) Group. Dental casts of the two groups were measured and compared at the ages of 0, 1, 3-4, and after 10 years. 1) In spite of apparent differences in palatal configurations at the age of 3-4 years, no significant differences in palatal size and area were noted between the groups. The cross-sectional areas in the VF Group were significantly larger than those in the PB Group in all the sections. 2) When the two groups were compared for rates of growth from 1 to 3-4 years, no significant differences in palatal size were noted, except in palatal width 1, although palatal growth from 1 to 3-4 years was more consistent and favorable in the VF Group. The rates of growth or change in palatal area and cross sectional-area 2 were significantly larger in the VF Group. 3) In spite of the apparent difference in palatal configuration, after age 10, no significant differences in palatal size, area, and depth were noted except in cross-sectional area 2.

Adolescent↗
PubMed1997

[Functional screening of p53 status in tumor cells using Saccharomyces cerevisiae].

We have detected both germ-line and somatic p53 mutations in lymphocytes, cell lines and tumor tissues using a functional analysis of p53 tumor suppressor gene based on yeast transcription assay. Through our screening projects of the p53 gene, a number of missense p53 mutations were identified as loss-of-function mutations. This method, previously termed FASAY, is rapid, sensitive, less-expensive and can be automated for screening both somatic and germ-line p53 mutations.

Genes, p53↗
PubMed1997

[p53 mutation does not determine prognosis in non-Hodgkin's lymphoma].

We studied the clinical significance of the extent of p53 protein expression by immunohistochemical analysis and p53 mutations by functional analysis of p53 in 42 patients with high and intermediate grade of Non-Hodgkin's Lymphoma (NHL). Neither p53 expression nor mutation correlated with short survival or resistance to chemoradiotherapy, implying that p53 mutation is not a prognostic factor in NHL.

Genes, p53↗
PubMed1997

[p53 as a molecular target for cancer therapy].

Development of novel strategies is required for cancer treatment because most human tumors are refractory to current conventional therapy. During the past decade, a number of oncogenes and tumor suppressor genes have been cloned and the molecular mechanisms as to how mutations in such genes contribute to tumor development are going to be clarified. It is, therefore, a great challenge to develop novel strategies for tumor specific therapy based on molecular biology of cancer. p53 tumor suppressor gene is one of the most frequently mutated genes in a variety of human cancers. This review paper introduces several recent approaches related to the p53 as a molecular target of cancer treatment, including (i) p53 status and chemo-radiosensitivity, (ii) p53 gene therapy, (iii) E1B-deficient adenovirus and (iv) restoration of p53 function by synthetic polypeptides.

Animals↗
PubMed1997

Spinal fusion using a vascularized fibular bone graft for a patient with cervical kyphosis due to neurofibromatosis.

We performed an anterior spinal fusion using a vascularized fibular bone graft combined with posterior fusion for a patient with severe cervical kyphosis due to neurofibromatosis. The kyphosis was corrected from 85 degrees preoperatively to 38 degrees postoperatively. A vascularized fibular bone graft is a useful surgical procedure in selected patients to obtain successful bony union.

Adolescent↗
PubMed1997

Two different hard palate closure techniques in two-stage palatoplasty: effects on velopharyngeal closure and articulation.

Two different hard palate closure techniques, in two-stage palatoplasty, was evaluated in 12 patients. The lip and soft palate were closed at 3 to 7 months of age. The patients were then divided into two groups of six and the hard palate closed at 17 to 23 months of age, either by a vomer flap (VF) with a skin graft (Osada's two-stage palatoplasty) in the VF group, or by the push-back (PB) procedure of the mucoperiosteal flap in the PB group. Velopharyngeal closure (VPC) during a gag reflex before and after hard palate closure, and the articulation of these patients after closure, were evaluated and compared between the two groups. Regarding VPC before hard palate closure, three "Poor" and three "Borderline" outcomes were noted in each group. We conclude that, by introducing the pharyngeal flap, the patients in the VF group obtained good articulation, actually comparable to that in the PB group.

Articulation Disorders↗
PubMed1996

Bone marrow stromal cells produce thrombopoietin and stimulate megakaryocyte growth and maturation but suppress proplatelet formation.

Production of blood cells is regulated by the interplay of various cytokines and bone marrow stromal cells. Recently, a ligand for the orphan receptor Mpl was identified as thrombopoietin (TPO), which specifically regulates megakaryocyte differentiation, and it was reported to be expressed mainly in liver and kidney. As it was found that thrombopoietin is also produced in bone marrow stromal cells, we studied further the roles of bone marrow stromal cells on megakaryocytopoiesis and platelet formation. The stromal cells stimulated growth and maturation of bone-marrow-derived megakaryocytes in the presence of thrombopoietin, and also supported growth of BaF3 cells expressing exogenous Mpl without thrombopoietin. Thrombopoietin induces drastic morphological change of megakaryocytes in bone marrow cells in vitro, ie, the formation of lengthy beaded cytoplasmic processes (proplatelet formation). However, when the purified megakaryocytes were cocultured with the stromal cells with or without thrombopoietin, most of the megakaryocytes adhered to the stromal cells and remained unchanged, while free megakaryocytes induced proplatelet formation. These observations indicated that the stromal cells in a hematopoietic microenvironment in bone marrow secrete thrombopoietin and stimulate proliferation and maturation of megakaryocytes, but the interaction of megakaryocytes with the stromal cells may suppress proplatelet formation.

Animals↗
PubMed1996

Attempt to obtain greater dermal depth of vascular injury using dye-enhanced laser technique: a new approach.

BACKGROUND AND OBJECTIVE: Although pulsed dye laser has been successfully used in the treatment of portwine stains, a number of patients had incomplete clearance because the depth of penetration by the pulsed dye laser was inadequate. This study was performed to establish the greater penetration depth of vascular injury using a dye-enhanced laser technique. STUDY DESIGN/MATERIALS AND METHODS: The ruby laser at 694.3 nm was used, and the corresponding specific dye was Prussian blue solution (maximum absorbance 694 nm). We compared the penetration depth of vascular injury by the ruby laser irradiation after the Prussian blue injection with that by the dye laser irradiation. A flashlamp dye laser with a pulse duration of 300 microseconds and a 5 mm diameter spot size was used to 6.2 J/cm2 at 590 nm. The Prussian blue solution was injected into the superficial epigastric artery of white male Japanese rabbits, immediately followed by the ruby laser exposure to 6.2 J/cm2 at a pulse duration of 283 microseconds in a 15 x 15 mm spotsize. Depth of penetration was measured from the dermoepidermal junction to the deepest site of vascular injury at 24 hours after laser exposure. RESULTS: Mean penetration of 590 nm of the dye laser light was 1.45 mm; mean penetration of the 694.3 nm ruby laser irradiation after the Prussian blue injection was 2.33 mm. Ruby laser penetration was greater than that of the dye laser. CONCLUSION: This study emphasizes that the ruby laser irradiation after the Prussian blue injection can induce deeper vascular injury than the dye laser inducing similar pathological changes.

Animals↗
PubMed1996

Expression of adhesion molecules on cytoplasmic processes of human megakaryocytes.

Megakaryocytes generate cytoplasmic processes (CP) that penetrate endothelial cells in the bone marrow sinus, and these processes may release platelets into the circulation at their terminal stage. Adhesion between the CP and endothelial cells may be important during the extension of CP. We examined the expression of adhesion molecules of the integrin family (CDw49b, CDw49d, CDw49e, CDw49f, CD18, CD11a CD11c, and CD11b), the immunoglobulin superfamily (CD54, CD56, CD58, and CD31), the selectin family (ELAM-1, LECAM-1, and CD62), and CD44, CD41b, and CD42b on platelets, megakaryocytes, and megakaryocytes with CP. No specific adhesion molecules were observed on the megakaryocytes with CP. Three staining patterns of adhesion molecules-homogeneous, speckled, and accumulated-were observed on the megakaryocytes with CP, but not on those without CP. Platelet integrins (i.e., CD41a, CDw49b, CDw49e and CDw49f) and GPIb (CD42b) were strongly and homogeneously stained on the CP. GMP-140 CD62) was weakly stained, in a speckled pattern. CD31 (PECAM-1) was also weakly stained but accumulated selectively on the tip of the CP. ANTI-CD31 suppressed CP formation of megakaryocytes. We speculate that the homodimerization of CD31 expressed on the tips of CP and endothelial cells is important for the extension of the processes and for the migration of megakaryocytes.

Antigens, CD↗
PubMed1995

Assessment of cancer susceptibility in humans by use of genetic polymorphisms in carcinogen metabolism.

Prevention is an important and effective measure for reducing death caused by cancer. Thus information on individual susceptibility to cancer is valuable in suggesting high risk individuals to avoid intake of carcinogenic substances and receive frequent physical screening. To this end, polymorphisms found within cytochrome P450 (CYP) genes implicated in the metabolism of procarcinogens are expected to be good genetic targets in assessing human cancer susceptibility. We have found polymorphisms in the CYP2E1 and CYP1A1 genes associated with lung cancer susceptibility, though there were some discrepancies from observations made by other investigators. Discrepancies among investigators from different regions, however, are very common in these pharmacogenetic studies. We present an explanation for these discrepancies, difficulties associated with prediction of relative risk of individuals, and future directions.

Carcinogens↗
PubMed1995

[Long-term results of surgical treatment for renal pelvic and ureteral tumors].

Fifty eight cases of primary tumors in the renal pelvis and ureter were treated at Toranomon Hospital between 1983 and 1992. They consisted of 32 renal pelvic tumors, 21 ureteral tumors and 5 tumors at both sites. The age of the patients ranged from 30 to 84 years (mean 63.1). Surgery was performed in 56 cases. Radical nephroureterectomy with concomitant ipsilateral retroperitoneal lymph node dissection was performed in 38 cases. The other surgeries were radical nephroureterectomy without lymph node dissection in 9, nephrectomy in 4, resection of ureter and reanastomosis in 3, radical nephroureterectomy and cystectomy in 1 and partial nephrectomy in 1. Pathologically, 53 were transitional cell carcinoma (TCC), 2 were TCC plus squamous cell carcinoma and 1 was TCC plus adenocarcinoma. Over-all survival rates (Kaplan-Meier) of 56 surgical cases at 1, 3, 5 years were 92.2, 83.7 and 72.8%, respectively. Combination chemotherapy (M-VAC or CAP) was performed in 9 cases of metastatic disease and 1 case of bilateral disease. Of these 10 cases, one achieved complete remission, 2 no change and 7 had progressive disease. Adjuvant chemotherapy was performed in 21 cases after surgery. These 21 patients were of high risk in recurrence either Grade 3 or pT3. However, the 5-year survival rate was 77.3% in these patients. Thus we conclude that the adjuvant chemotherapy in high risk patients was effective in our cases.

Adult↗
PubMed1994

The protective effect of preconditioning on reperfusion-induced arrhythmia is lost by treatment with superoxide dismutase.

The purpose of this study was to investigate the relation between free radicals and the effect of preconditioning on reperfusion arrhythmias using the isolated working rat heart model. Rats were divided into 3 groups: control, preconditioned without superoxide dismutase (SOD) and preconditioned with SOD (n = 8 each group). The incidence of reperfusion-induced ventricular fibrillation (Vf) in the preconditioned without SOD group was reduced from 100% to 13% (p < 0.005 vs control). This protective effect of preconditioning was not observed in the SOD-treated group (incidence of Vf increased from 13% to 75%, p < 0.025). The protective effect of preconditioning on reperfusion arrhythmias is related to the presence of oxygen free radicals which occur during the reperfusion period of the preconditioning phase.

Animals↗
PubMed1993

Acute swim stress increases benzodiazepine receptors, but not GABAA or GABAB receptors, in the rat cerebral cortex.

We have examined the effects of swim stress on gamma-aminobutyric acidA (GABAA), GABAB and benzodiazepine (BZD) receptors in synaptic membranes from rat brain. Acute, but not repeated, stress increased the number of BZD receptors in the cerebral cortex. The stress manipulation did not change BZD receptors either in the hippocampus or cerebellum. Furthermore, both GABAA and GABAB receptors did not change in the cerebral cortex, hippocampus or cerebellum after acute and repeated stress. GABA-stimulated BZD binding was not changed following acute or repeated stress. These results suggest that cortical BZD receptors are closely related to responses to acute stress.

Animals↗
PubMed1993

Use of cultured human epidermal allografts for the treatment of extensive partial thickness scald burn in children.

In spite of recent progress in burn treatment, the early surgical therapy of partial thickness scald burns in children is still controversial. Early tangential excisions is not easily applicable for these patients because of difficulties in determination of the burn depth and probable physiological derangement after surgery. Hypertrophic scar formation and wound contraction after meshed autografts are other limitations. For these reasons, conservative treatment, not early excision therapy, has been chosen initially for these injuries. We used cultured epidermal allografts for extensive, partial thickness scald burns, during the early post-burn period without escharectomy. Fifty to 100% of the engrafted superficial dermal burns were epithelialized within 7 days. In contrast, untreated identical wounds remained open. Repeated grafting of cultured allografts on unexcised wound granulations of dermal burns also enhanced epithelialization. Long term results showed that hypertrophic scar formation in the mixed superficial and deep dermal burns was reduced when cultured allografts were used. Allografting of the cultured epidermis without surgical excision apparently promoted the rapid regeneration of the partial thickness burns. Procedural complications did not occur. Cultured allografts should be used as an effective and safe biological dressing for partial thickness scald burns in children.

Burns↗