PubMed Health⌕ Search

Biomedical subjects

K Sugimoto

Publications and source records attributed to K Sugimoto.

At least 19 recordsLinked to original sources
PubMed2006

Preparation of prefabricated vascularized bone graft with neoangiogenesis by combination of autologous tissue and biodegradable materials.

Prefabricated vascularized bone grafts have previously been prepared by combining an autologous vessel bundle with auto-particulate cancellous bone and marrow (PCBM) and a biodegradable membrane. Only small quantities of low-density vascularized bone tissue have been formed using this method. The authors of the present study combined beta-tricalcium phosphate (beta-TCP), a biodegradable ceramic, with a prefabricated vascularized bone graft to augment osteogenesis. A saphenous vessel bundle from a rat was wrapped in a biodegradable membrane. Then, autologous PCBM was mixed with beta-TCP granules and packed into the rolled membrane. In the control group, beta-TCP was omitted. Bone formation was histologically assessed 6 and 9 weeks after implantation. The volume of newly formed bone tissue in the rolled membrane was greater in the presence of beta-TCP granules than in the control. Microvessels had formed throughout the new bone tissue. When a prefabricated vascularized bone graft was onlay-grafted to the femur of the same rat, the prefabricated vascularized bone graft directly fused to the cortical surface of the femur, with no intervening fibrous tissue. These findings suggest that beta-TCP in combination with PCBM enhances the volume and density of bone tissue in prefabricated vascularized bone grafts.

Absorbable Implants↗
PubMed2006

Phase II trial of radiotherapy after hyperbaric oxygenation with chemotherapy for high-grade gliomas.

We conducted a phase II trial to evaluate the efficacy and toxicity of radiotherapy immediately after hyperbaric oxygenation (HBO) with chemotherapy in adults with high-grade gliomas. Patients with histologically confirmed high-grade gliomas were administered radiotherapy in daily 2 Gy fractions for 5 consecutive days per week up to a total dose of 60 Gy. Each fraction was administered immediately after HBO with the period of time from completion of decompression to irradiation being less than 15 min. Chemotherapy consisted of procarbazine, nimustine (ACNU) and vincristine and was administered during and after radiotherapy. A total of 41 patients (31 patients with glioblastoma and 10 patients with grade 3 gliomas) were enrolled. All 41 patients were able to complete a total radiotherapy dose of 60 Gy immediately after HBO with one course of concurrent chemotherapy. Of 30 assessable patients, 17 (57%) had an objective response including four CR and 13 PR. The median time to progression and the median survival time in glioblastoma patients were 12.3 months and 17.3 months, respectively. On univariate analysis, histologic grade (P=0.0001) and Karnofsky performance status (P=0.036) had a significant impact on survival, and on multivariate analysis, histologic grade alone was a significant prognostic factor for survival (P=0.001). Although grade 4 leukopenia and grade 4 thrombocytopenia occurred in 10 and 7% of all patients, respectively, these were transient with no patients developing neutropenic fever or intracranial haemorrhage. No serious nonhaematological or late toxicities were seen. These results indicated that radiotherapy delivered immediately after HBO with chemotherapy was safe with virtually no late toxicity in patients with high-grade gliomas. Further studies are required to strictly evaluate the effectiveness of radiotherapy after HBO for these tumours.

Adult↗
PubMed2006

Plasma brain natriuretic peptide concentrations in patients undergoing pulmonary vein isolation.

OBJECTIVE: To examine whether raised plasma brain natriuretic peptide (BNP) concentrations decrease after successful pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). METHODS: 53 patients (mean age 53 years) with drug-refractory, paroxysmal lone AF underwent segmental ostial PVI. Blood samples were collected before and after PVI. BNP concentrations were determined by immunoassays. RESULTS: Median plasma BNP concentrations were significantly higher in patients with lone AF than in controls (patients with supraventricular tachyarrhythmias, n = 21) (64.6 (71.9) v 13.9 (7.8) pg/ml, p < 0.01). AF recurred in 21 patients after the initial PVI procedure (recurrent AF group), and the others were free from AF without antiarrhythmic drugs (non-recurrent AF group). BNP concentrations were significantly decreased by PVI in the non-recurrent AF group (38.9 (39.1) to 18.3 (16.1) pg/ml, p < 0.01) but not in the recurrent AF group. CONCLUSIONS: Raised plasma BNP concentrations decreased after successful segmental ostial PVI in patients with AF.

Atrial Fibrillation↗
PubMed2006

Spindle checkpoint protein Bub1 corrects mitotic aberrancy induced by human T-cell leukemia virus type I Tax.

Bub1 is a component of the mitotic spindle checkpoint apparatus. Abnormality of this apparatus is known to cause multinuclei formation, a hallmark of chromosomal instability (CIN). A549, aneuploid cell line, aberrantly passed through the mitotic phase and became multinuclei morphology in the presence of nocodazole. Time-lapse videomicroscopy showed unreported bizarre morphology, which we named 'mitotic lobulation' in A549 cells just before the exit from mitosis and multinuclei formation. External expression of wild-type Bub1-EGFP clearly suppressed the multinuclei formation by retaining A549 cells at the mitotic phase during 48 h of time-lapse observation. This suppressive effect on mitotic aberrancy should not be mere restoration of normal Bub1 function, because A549 cells express proper amount of Bub1, which distributed cytoplasm during interphase and concentrated at kinetochore in metaphase. Furthermore, external expression of wild-type Bub1-EGFP suppressed multinuclei formation induced by Tax both in A549 and HeLa cells. Tax is known to induce mitotic abnormality by binding and inactivating Mad1. These observations, therefore, suggest functional redundancy between Bub1 and other mitotic checkpoint protein(s) and a possibility of correction of mitotic aberrancy by external Bub1 expression.

Cell Cycle Proteins↗
PubMed2006

Low tibial osteotomy for varus-type osteoarthritis of the ankle.

In this retrospective study we have assessed the results of low tibial valgus osteotomy for varus-type osteoarthritis of the ankle and its indications. We performed an opening wedge osteotomy in 25 women (26 ankles). The mean follow-up was for eight years and three months (2 years 3 months to 17 years 11 months). Of the 26 ankles, 19 showed excellent or good clinical results. Their mean scores for pain, walking, and activities of daily living were significantly improved but there was no change in the range of movement. In the ankles which were classified radiologically as stage 2 according to our own grading system, with narrowing of the medial joint space, and in 11 as stage 3a, with obliteration of the joint space at the medial malleolus only, the joint space recovered. In contrast, such recovery was seen in only two of 12 ankles classified as stage 3b, with obliteration of the joint space advancing to the upper surface of the dome of the talus. Low tibial osteotomy is indicated for varus-type osteoarthritis of stage 2 or stage 3a.

Activities of Daily Living↗
PubMed2005

A Japanese family with Alport syndrome associated with esophageal leiomyomatosis: genetic analysis of COL4A5 to COL4A6 and immunostaining for type IV collagen subtypes.

BACKGROUND: In some families, X-linked Alport syndrome (AS) is associated with diffuse leiomyomatosis. We describe clinical, pathologic and molecular-genetic findings in a Japanese family with this inheritance mode of AS in association with leiomyomatosis. PATIENT: AS was diagnosed in a one-year-old boy with recurrent aspiration pneumonia caused by esophageal stenosis from leiomyomatosis. Diagnosis was confirmed by electron microscopy coupled with type IV collagen chain subtype staining in a renal biopsy specimen. His mother, who exhibited esophageal leiomyomatosis and is heterozygous for AS, showed a discontinuous staining pattern for collagen alpha5(IV) chain along the epidermal basement membrane in a skin biopsy specimen. Genetic analysis in the boy revealed the deletion of the first two exons of COL4A6 together with deletion of the 5' end of COL4A5. Despite administration of cyclosporin A, massive proteinuria has persisted in the boy, although renal function otherwise remains normal. CONCLUSION: Identification of an AS patient during infancy is extremely rare. Clinical manifestations, including macroscopic hematuria, cataracts and leiomyomatosis caused by the large deletion involving COL4A5 to COL4A6, led to early presentation with AS.

Collagen Type IV↗
PubMed2004

Pattern of collaterals, type of infarcts, and haemodynamic impairment in carotid artery occlusion.

BACKGROUND: In internal carotid artery (ICA) occlusion, increased oxygen extraction fraction (OEF) indicates inadequate collateral blood flow distal to the occlusion, which may be caused by poor function of collateral pathways. In ICA occlusion, the circle of Willis may be the major collateral pathway, while the collaterals through the ophthalmic artery and leptomeningeal vessels may be recruited when collateral flow through the circle of Willis is inadequate. Conversely, ischaemic lesions may affect the adequacy of collateral blood flow by reducing the metabolic demand of the brain. OBJECTIVE: To determine whether the pattern of collateral pathways and the type of infarcts are independent predictors of OEF in ICA occlusion. METHODS: We studied 42 patients with symptomatic ICA occlusion. The presence of Willisian, ophthalmic, or leptomeningeal collaterals was evaluated by conventional four vessel angiography. The infarcts on magnetic resonance imaging were categorised as territorial, border zone (external or internal), striatocapsular, lacunar, and other white matter infarcts. The value of OEF in the affected hemisphere was measured with positron emission tomography as an index of haemodynamic impairment. RESULTS: Using multivariate analysis, the presence of any ophthalmic or leptomeningeal collaterals and the absence of striatocapsular infarcts were significant and independent predictors of increased OEF. CONCLUSIONS: In patients with symptomatic ICA occlusion, the supply of collateral flow, which is affected by the pattern of collateral pathways, and the metabolic demand of the brain, which is affected by the type of infarct, may be important factors determining the severity of haemodynamic impairment.

Aged↗
PubMed2004

A boy with Japanese Dent's disease exhibiting abnormal calcium metabolism and osseous disorder of the spine: defective megalin expression at the brushborder of renal proximal tubules.

We encountered a 16-year-old boy with Japanese Dent's disease who exhibited renal insufficiency and an osseous disorder of the spine. Proteinuria first was noted at the age of 2 years. At 13 years, the patient underwent analysis of the CLCN5 gene, which identified missense mutation (I524K) in exon 10. During follow-up, a marked increase in urinary beta2-microglobulin was associated with mild deterioration of renal function. At the age of 15 years, hypocalcemia (7.5 mg/dl) accompanied by an increased plasma concentration of alkaline phosphatase was first detected. At that time, plasma concentration of 25(OH)D3 and 1'alpha25(OH)2D3 were low accompanied by a high plasma parathyroid hormone concentration. A renal biopsy specimen revealed tubulointerstitial alterations including mononuclear cell infiltration, partial fibrosis and focal glomerular sclerosis. Immunofluorescence revealed weak, discontinuous staining of megalin along the brushborder of renal proximal tubules. Western blotting demonstrated decreased urinary excretion of megalin. Thus, clinical manifestations and prognosis may vary in Japanese Dent's disease. Reduced megalin expression may have disturbed calcium homeostasis, leading to osseous disorder in our patient.

Adolescent↗
PubMed2004

Oxygen extraction fraction and acetazolamide reactivity in symptomatic carotid artery disease.

OBJECTIVE: It has been proposed that cerebral blood flow (CBF) response to acetazolamide may be reduced according to the degree of autoregulatory vasodilation in regions with normal oxygen extraction fraction (OEF), whereas the CBF response may be absent in regions with increased OEF where vasodilation may be maximal in response to reduced perfusion pressure. The objective of this study was to test this hypothesis. METHODS: Positron emission tomography (PET) was used to study 30 symptomatic patients with carotid artery steno-occlusive lesions. CBF at baseline and 10 minutes after an intravenous injection of 1 g acetazolamide was measured. The correlation between the change in CBF during acetazolamide administration and the baseline value of OEF in the affected hemisphere was examined. RESULTS: The baseline OEF value was inversely and non-linearly correlated with the percentage change in CBF during acetazolamide administration (R(2) = 0.25, p = 0.02). There was an upward trend of OEF with diminishing acetazolamide response below a critical level around zero response. Acetazolamide response less than 6.65% over baseline (sensitivity 100%, specificity 89%, positive predictive value 50%, negative predictive value 100%) was established as most helpful in predicting abnormally high OEF. CONCLUSIONS: The inverse, non-linear relationship between OEF and CBF response to acetazolamide suggests that these two measurements may not identify haemodynamic impairment in the same patients.

Acetazolamide↗
PubMed2003

Unilateral ocular subalbinism in a laboratory Beagle dog.

Blue discoloration of the iris was found in the left eye of a male laboratory Beagle dog, which had a normal tricolor coat and clinically showed no visual impairment. Ophthalmoscopically, the affected eye revealed red-colored tigroid fundus, in which no tapetum was present. The retinal vasculature and the optic disc showed no noticeable changes. Histopathologically, in the left eye melanocytes had extremely few melanin granules in the anterior segment, including the anterior border layer, in the stroma and sphincter muscle of the iris and in the stroma of the ciliary body and choroid. However, the posterior pigment epithelium of the iris, the pigment epithelium of the ciliary body and the retinal pigment epithelium showed normal pigmentation. The tapetal elements were completely absent. Number and distribution of the S-100 protein-positive melanocytes with or without melanin granules in the iris, ciliary body and choroid of the left eye were similar to those of the normal right eye. Ultrastructurally, melanocytes in the anterior segment of the affected iris possessed no or few melanosomes which were incompletely melanized. In the right eye, no abnormal features were observed. Based on these results, the present case was diagnosed as unilateral ocular subalbinism with tapetal aplasia in a Beagle dog.

Albinism, Ocular↗
PubMed2003

The G1 domain of aggrecan released from porcine articular cartilage forms stable complexes with hyaluronan/link protein.

OBJECTIVE: To raise peptide antibodies recognizing the C-terminal amino acid sequence in the G1 domain of porcine aggrecan, generated by the action of either aggrecanase or neutral metalloproteinase(s), in rabbits and to use them to investigate the release of aggrecan from porcine articular cartilage. METHOD: An explant culture system was used to investigate the release of the G1 domain of aggrecan from porcine articular cartilage treated with retinoic acid or interleukin 1beta and to study how the activity of these agents is modified by the proteinase inhibitor, batimastat (BB94). RESULTS: Retinoic acid and interleukin 1beta induced both enzyme activities and the release of the G1 domain into the culture medium. Proteinase activity was significantly reduced when the tissue was incubated in the presence of BB94. The functional properties of the enzyme-generated G1 domain were studied using large-pore, agarose/polyacrylamide gel electrophoresis, and it was shown to interact with hyaluronan and link protein. CONCLUSIONS: The results show that there must be a mechanism for removing a functional G1 domain from aggrecan during tissue turnover using this culture system.

Aggrecans↗
PubMed2002

Development of a platform to evaluate and limit in-stent restenosis.

The objective of this work was to develop a platform to evaluate and deliver putative therapeutic agents for in-stent restenosis. Arterial stenting is applied in more than 60% of balloon angioplasties for treating cardiovascular disease. However, stented arteries encounter accelerated rates of restenosis. No prior platform has allowed evaluation or local management of in-stent restenosis without perturbing the very system being examined. A stainless steel, balloon-expandable stent was modified to serve as an ablumenal drug delivery platform. Several combinations of bioerodible polymer microspheres and gels were evaluated for channel retention under in vitro flow and in vivo conditions. A stent-anchored hybrid system prevented material embolization under all conditions. Unlike prior platforms, these stents do not alter local inflammation or in-stent plaque formation relative to conventional Palmaz-Schatz stents after in vivo deployment. The system also proved sensitive enough to detect plaque reduction with an antirestenotic agent. We conclude that a platform to evaluate and deliver therapeutic agents for in-stent restenosis has been achieved.

Animals↗
PubMed2002

Subtalar arthrography in recurrent instability of the ankle.

Subtalar arthrography was done in 37 feet of 35 patients in whom recurrent instability of the ankle was diagnosed. There were 16 male and 19 female patients, with a mean age of 29.1 years (range, 11-56 years). The mean interval between the injury and arthrography was 4 years 3 months (range, 6 months-22 years). Anteroposterior, lateral, and oblique radiographs were obtained for all patients. Any leakage during arthrography into the ankle, tendon sheaths, or sinus tarsi was recorded. An oblique view of the microrecess along the interosseous ligament and an anteroposterior view of the lateral recess just under the end of the fibula were examined. At surgery, 13 feet had combined injuries of the anterior talofibular and calcaneofibular ligaments, and 24 feet had isolated injury of the anterior talofibular ligament. The findings of the two groups were significantly different when examined for leakage into the ankle, leakage into the peroneal tendon sheath, and the presence of the lateral recess. Presence of contrast medium in at least two of these three positive arthrographic findings showed 92.3% sensitivity and 87.5% specificity in making the diagnosis of calcaneofibular ligament injury. Subtalar arthrography is valuable in making the diagnosis of calcaneofibular ligament injury in recurrent instability of the ankle.

Adolescent↗