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Biomedical subjects

H Tsuchiya

Publications and source records attributed to H Tsuchiya.

At least 19 recordsLinked to original sources
PubMed2006

Anisotropy and corotation of galactic cosmic rays.

The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

Journal Article↗
PubMed2005

Reconstruction using an autograft containing tumour treated by liquid nitrogen.

We describe a method of reconstruction using tumour-bearing autograft treated by liquid nitrogen in 28 patients. The operative technique consisted of en bloc excision of the tumour, removal of soft tissue, curettage of the tumour, drilling and preparation for internal fixation or prosthetic replacement before incubation for 20 minutes in liquid nitrogen, thawing at room temperature for 15 minutes, thawing in distilled water for ten minutes, and internal fixation with an intramedullary nail, plate or composite use of prosthetic replacement. Bone graft or cement was used to augment bone strength when necessary. The limb function was rated as excellent in 20 patients (71.4%), good in three (10.7%), fair in three (10.7%), and poor in two (7.1%). At the final follow-up six patients had died at a mean of 19.8 months after the operation, while 21 remained free from disease with a mean follow-up of 28.1 months (10 to 54). One patient is alive with disease. Bony union was seen at a mean of 6.7 months after the operation in 26 patients. Complications were encountered in seven patients, including three deep infections, two fractures, and two local recurrences. All were managed successfully. Our results suggest that this is a simple and effective method of biological reconstruction.

Adolescent↗
PubMed2004

Observation by an air-shower array in Tibet of the multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun.

We report on the solar diurnal variation of the galactic cosmic-ray intensity observed by the Tibet III air shower array during the period from 1999 to 2003. In the higher-energy event samples (12 and 6.2 TeV), the variations are fairly consistent with the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun, while the variation in the lower-energy event sample (4.0 TeV) is inconsistent with this anisotropy. This suggests an additional anisotropy superposed at the multi-TeV energies, e.g., the solar modulation effect. This is the highest-precision measurement of the Compton-Getting anisotropy ever made.

Journal Article↗
PubMed2004

Fibronectin protects endotoxin-induced liver injury after partial hepatectomy in rats.

Endotoxemia following extended hepatectomy may be a cause of postoperative death. Multiple organ failure related to septemia is a common cause of early mortality after liver transplantation. Fibronectins (Fns) are involved in cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing, and ischemic injury. Studies were performed to determine whether Fn influences the survival rate of rats subjected to endotoxin-induced liver injury after partial hepatectomy. Male Sprague-Dawley rats were intravenously administered lipopolysaccharide (LPS) 48 hours after 70% hepatectomy. Prior to LPS administration, plasma Fn or bovine serum albumin was given intravenously. The survival rate of the Fn-treated group was higher than that of the controls. Fn prevented increases in serum enzyme activity and total bilirubin related to liver injury. The levels of inflammatory cytokines including tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 interferon-gamma were also significantly lower in the Fn-treated than the control group. Furthermore, the number of apoptotic cells and the degree of necrosis in the remnant liver were significantly decreased in the Fn-treated rats compared with controls. These results indicate that Fn prevents endotoxin-induced liver injury after partial hepatectomy, at least in part through inhibiting the production of inflammatory cytokines, and the necrosis apoptosis in the remaining liver.

Animals↗
PubMed2003

Differentiation of soft tissue haemangioma by 201Tl scintigraphy.

Radiological diagnosis of deep soft tissue is often difficult. In the present study, thallium-201 ( Tl) uptake into haemangiomas and deep malignant soft tissue tumours was investigated in order to assess its clinical utility. Tl scintigraphy was reviewed in four patients presenting with soft tissue haemangiomas. Early and delayed planar images, obtained at 15 min and 3 h following the intravenous injection of Tl (111 MBq), were examined. The Tl uptake ratio was calculated by dividing the count density of the tumour region of interest (ROI) by that of the background ROI. Results were compared with those of five cases of rhabdomyosarcoma and a single instance of angiosarcoma. All haemangioma lesions demonstrated increased Tl uptake in early images. However, Tl uptake in delayed images was markedly decreased. No significant differences were observed in the early uptake ratio between haemangiomas (1.60-2.72) and reference malignant tumours (1.48-2.45); however, the difference was significant in delayed images (range, 1.01-1.26 vs. 1.43-2.03, respectively) ( P<0.02). Deep soft tissue haemangiomas revealed Tl accumulation in early images; however, a rapid washout was observed in delayed images. This distinctive feature may facilitate the use of Tl scintigraphy in the diagnosis of haemangiomas.

Adolescent↗
PubMed2002

Melatonin deficiency and fibrous dysplasia: might a relation exist?

Fibrous dysplasia of bone might be monostotic, polystotic, or occurs as a part of McCune-Albright syndrome and Jaffe-Lichtenstein syndrome. Activating mutations of GNAS1 gene was identified in patients with fibrous dysplasia. However, fibrous dysplasia might occur in the absence of these mutations and fibrous dysplastic tissue was produced in vitro by the effects of excess exogenous cAMP on human osteogenic cells. It was proved that the fibrous dysplastic tissue is deficient in bone sialoprotein. Melatonin deficiency might be hypothesized in syndromes associated with fibrous dysplasia or formation of fibrous dysplasia-like tissue. The receptor RZR/ROR is the nuclear receptor of melatonin and the human bone sialoprotein gene contains a RZR/ROR response element. It was supposed that binding of melatonin to its membrane receptors results in changes in the levels of activity of nuclear cAMP that lead to alteration of expression of bone sialoprotein. Also, melatonin deficiency might increase cAMP in bone through its effect on prostaglandins of the E group. Further, melatonin deficiency might explain precocious puberty in cases of McCune-Albright syndrome. We might hypothesize that melatonin deficiency might play a role in development of fibrous dysplasia in some cases.

Bone Development↗
PubMed2002

Simple bone cyst is not a single entity: point of view based on a literature review.

Three varieties of simple bone cysts have not attracted a lot of clinical attention: simple bone cysts in non-tubular bones, multiple cysts and epiphyseal cysts. Simple bone cysts occurring in non-tubular bones form about 4-10% of total cases, with a higher age incidence and better prognosis. Epiphyseal simple bone cysts have a higher age incidence, a lower male/female ratio, a very high humerus/femur ratio and higher incidence of tibial location than the classic metaphyseal cysts. Multiple cysts occur in the higher age group and show very high male predominance. In the review of the literature, 15 cysts (35.7%) were in non-tubular bones and six cysts (14.3%) were epiphyseal. They have a better prognosis than the classic metaphyseal ones. Four clinico-anatomic varieties of simple bone cysts could be recognized: classic metaphyseal, non-tubular, epiphyseal, and multiple. Venous obstruction might be the cause of all forms of the disease but the etiologies of venous obstruction causing the last three clinical forms might be different from that causing the classic metaphyseal ones.

Bone Cysts↗
PubMed2002

Intense 201 Tl uptake in giant-cell tumour of bone.

The aim of this study was to determine the characteristics and clinical usefulness of 201Tl scintigraphy in giant-cell tumour of bone (GCT). Twenty-one patients with histopathologically proven benign GCT (22 lesions; 18 primary and four recurrent) underwent 201Tl scintigraphy. We also studied conventional osteosarcoma (10 lesions), a very common primary malignant bone tumour; and chordoma in the sacrum (four lesions), an entity requiring differential diagnosis from GCT of the sacrum. Early and delayed planar imaging was performed at 15 min (early) and 3 h (delayed) after the intravenous injection of 201Tl chloride (111 MBq). The Tl uptake ratio was calculated by dividing the count density of the tumour region of interest (ROI) by that of the background ROI. All GCT lesions showed increased Tl uptake in both early and delayed images. The mean Tl uptake ratios of primary GCT were 4.7 (range, 2.0-11.1) in the early images and 2.2 (range, 1.4-3.6) in the delayed images, and those of recurrent lesions were 5.8 (range, 2.4-11.5) in the early images and 2.7 (range, 2.0-4.3) in the delayed images. There were no significant differences between the uptake ratios in GCT and osteosarcoma, but the values of GCT tended to be higher than those of osteosarcoma, 3.1 (range, 1.7-4.4) in the early images and 1.8 (range, 1.3-2.3) in the delayed images. Chordoma did not show appreciable Tl uptake: the uptake ratio was 1.19 (range, 0.98-1.5) in the early images and 1.1 (range, 1.0-1.3) in the delayed images. In GCT, a benign lesion, Tl scintigraphy demonstrated marked uptake in both primary and recurrent lesions with no exceptions, precluding the use of Tl scintigraphy for the differential diagnosis of GCT from malignant tumours. However, the Tl scintigraphy can be used for excluding GCT when no lesional Tl uptake is observed, and diagnosing recurrent lesions on post-operative follow-up.

Adult↗
PubMed2002

Cannulation of simple bone cysts.

We describe a consecutive series of 26 patients with simple bone cysts who were treated by curettage, multiple drilling and continuous decompression by the insertion of either a cannulated screw or a pin. In the first 15 patients we used titanium cannulated screws (group 1) and in the next 11 a cannulated hydroxyapatite pin (group 2). Satisfactory healing was achieved in 12 patients in group 1 (80%) and in all in group 2. This technique seems to be a promising option for the treatment of simple bone cysts. The cannulated hydroxyapatite pin is recommended because of its higher success rate and the fact that it does not need to be removed.

Adolescent↗
PubMed2002

Osteosarcoma around the knee. Intraepiphyseal excision and biological reconstruction with distraction osteogenesis.

In 11 patients juxta-articular osteosarcoma around the knee was treated by intraepiphyseal excision of the tumour and reconstruction of the bone defect by distraction osteogenesis. Preoperative and postoperative chemotherapy was given to eight patients with high-grade tumours. The articular cartilage of the epiphysis and a maximum of healthy soft tissues were preserved. Distraction osteogenesis was then carried out. The mean gain in length was 9.7 cm. Full function of the limb was preserved in all except one patient, with a mean follow-up of 53.8 months. Treatment of juxta-articular osteosarcomas around the knee with joint preservation and biological reconstruction using distraction osteogenesis can give excellent functional results.

Adolescent↗
PubMed2001

Candesartan inhibits carotid intimal thickening and ameliorates insulin resistance in balloon-injured diabetic rats.

This study investigates the effects of candesartan, an angiotensin II type 1 receptor blockade, on carotid arterial intimal thickening and glucose tolerance in balloon-injured male Wistar fatty rats and their littermates (Wistar lean rats). Candesartan was orally administered to 12-week-old rats for 21 days, and age-matched rats without the agent were used as the respective controls. Balloon catheterization in the left common carotid artery was performed on day 7, and the artery was removed on day 14 for histological analysis. Compared with the area ratios of the neointima/media in fatty rats without treatment, the ratios in fatty rats treated with candesartan at 1 mg. kg(-1). d(-1) and lean rats without treatment were significantly decreased to 65%; on the other hand, the ratios of fatty rats treated with candesartan at 10 mg. kg(-1). d(-1) and lean rats treated with 1 mg. kg(-1). d(-1) were reduced to 35%, and those of lean rats treated with 10 mg. kg(-1). d(-1) were reduced to 28%. The administration of candesartan also decreased the level of plasma glucose time- and dose-dependently in fatty rats. In an intragastric glucose load, the levels of both glucose and insulin at 30 and 60 minutes were significantly decreased when fatty rats were treated with candesartan at 10 mg. kg(-1). d(-1). In cultured vascular smooth muscle cells from fatty rats, insulin-stimulated Akt (New England Biolabs) phosphorylation and 2-deoxy-D-glucose uptake were inhibited to 59% and 68%, respectively, by angiotensin II, but the effects were ameliorated by the addition of 10(-7) mol/L candesartan. We conclude that candesartan could be effective for the suppression of vascular smooth muscle cell growth dose-dependently in Wistar fatty and lean rats. Furthermore, the agent could improve insulin resistance in Wistar fatty rats.

Angiotensin Receptor Antagonists↗
PubMed2001

Intracellular trafficking and transgene expression of viral and non-viral gene vectors.

The objective of this review is to summarize the critical steps in intracellular trafficking and the principal factors involved in transgene expression by a comparison of viral and non-viral gene vectors. Intracellular trafficking of viral and non-viral gene vectors are reviewed kinetically as well as from the mechanistic point of view. The peptide-dependent specific mechanism of endosomal escape by viral vectors is compared with the non-specific mechanism of non-viral vectors. Regarding the nuclear transport of DNA, a number of recently developed strategies in non-viral vectors such as the application of nuclear localization signals or cell specific transcription factors are summarized in comparison with viral nuclear gene delivery. The molecular mechanisms of transcription and the translation of delivered genes to nucleus are also summarized in view of drug delivery systems. This information is intended to serve as a basis for developing a new gene delivery system for both viral and non-viral gene vectors. Optimizing the gene delivery system by integrating this intracellular trafficking as well as transgene expression will be required in order to develop an efficient and an safe gene delivery system.

Animals↗
PubMed2001

Specific interaction of the potassium channel beta-subunit minK with the sarcomeric protein T-cap suggests a T-tubule-myofibril linking system.

Ion-channel beta-subunits are ancillary proteins that co-assemble with alpha-subunits to modulate gating kinetics and enhance stability of multimeric channel complexes. They provide binding sites for other regulatory proteins and are medically important as the targets of many pharmacological compounds. MinK is the beta-subunit of the slow activating component of the delayed rectifier potassium current (I(Ks)) channel, and associates with the alpha-subunit, KvLQT1. We report here that minK specifically interacts with the sarcomeric Z-line component, T-cap (also called telethonin). In vitro interaction studies indicated that the cytoplasmic domain of minK specifically binds to the sixteen C-terminal residues of T-cap; these residues are sufficient for its interaction with minK. Consistent with our in vitro studies, immunofluorescence staining followed by confocal analysis revealed that both minK and T-cap are localized within the Z-line region in cardiac muscle. Striated staining of minK was observed in non-washed, membrane-intact cardiac myofibrils, but not in well-washed, membrane-removed cardiac myofibrils, suggesting that minK localizes on T-tubular membranes surrounding the Z-line in the inner ventricular myocardium. Together with our previous data on the colocalization and interaction of T-cap with the N-terminus of the giant protein titin in the periphery of the Z-line, these data suggest that T-cap functions as an adapter protein to link together myofibrillar components with the membranous beta-subunit of the I(Ks) channel. We speculate that this interaction may contribute to a stretch-dependent regulation of potassium flux in cardiac muscle, providing a "mechano-electrical feedback" system.

Amino Acid Sequence↗
PubMed2001

Single cell analysis of CAG repeat in brains of dentatorubral-pallidoluysian atrophy (DRPLA).

Somatic mosaicism of an expanded repeat is present in tissues of patients with triplet repeat diseases. Of the spinocerebellar ataxias associated with triplet repeat expansion, the most prominent heterogeneity of the expanded repeat is seen in dentatorubral-pallidoluysian atrophy (DRPLA). The common feature of this somatic mosaicism is the difference in the repeat numbers found in the cerebellum as compared to other tissues. The expanded allele in the cerebellum shows a smaller degree of expansion. We previously showed by microdissection analysis that the expanded allele in the granular layer in DRPLA cerebellum has less expansion than expanded alleles in the molecular layer and white matter. Whether this feature of lesser expansion in granule cells is common to other types of neurons is yet to be clarified. We used a newly developed excimer laser microdissection system to analyze somatic mosaicism in the brains of two patients, one with early- and another with late-onset DRPLA, and used single cell PCR to observe the cell-to-cell differences in repeat numbers. In the late onset patient, repeat expansion was more prominent in Purkinje cells than in granule cells, but less than that in the glial cells. In the early onset patient, repeat expansion in Purkinje cells was greater than in granule cells but did not differ from that in glial cells. These findings suggest that there is a difference in repeat expansion among neuronal subgroups and that the number of cell division cycles is not the only determinant of somatic mosaicism.

DNA Mutational Analysis↗
PubMed2001

Effect of myocutaneous inflammatory changes caused by intra-arterial chemotherapy on the outcome of patients who undergo limb-saving surgery.

BACKGROUND: This study examined the effect of myocutaneous inflammatory changes caused by intra-arterial chemotherapy on the outcome of patients who undergo limb-saving surgery. METHODS: One hundred seven patients with malignant bone and soft tissue tumors were administered intra-arterial cisplatin and caffeine preoperatively with or without doxorubicin. Nine patients (8.4%) who had had myocutaneous inflammatory reactions were reviewed to determine the effects of this complication on limb-saving surgery. RESULTS: The patients complained of unbearable and continuous pain while undergoing intra-arterial infusion. Gait disturbances and muscle weakness were caused by their severe regional pain, resulting in the use of crutches even before surgery. Extended areas of necrotic skin and muscle were resected simultaneously with limb-saving surgery on four patients. Myocutaneous necrosis in one patient, indurations in two patients, and flares in two patients were not treated surgically. Pain relief was provided to eight patients at some point. Four patients with extensive myocutaneous necrosis around the knee joint had restricted range of motion and poor functional results. Radionuclide angiography using 99m-Technetium-macroaggregated albumins was performed to evaluate the blood flow to the affected muscle and tumor. It showed marked increase of the radioisotope perfusion in the affected muscles but little uptake in the tumor. These results may suggest that the affected muscles diminish the effects of anticancer drugs on the tumors. CONCLUSIONS: Myocutaneous inflammatory reactions should be prevented if possible to obtain good limb function and chemotherapeutic effects in patients who undergo intra-arterial chemotherapy. Resection of necrotic tissue is mandatory to relieve pain.

Adolescent↗
PubMed2001

Short-term nonfrozen storage of mouse epididymal spermatozoa.

Six simple methods for short-term (up to 8 d), nonfrozen (5 to 20 degrees C) storage of mouse epididymides were compared with respect to the motility and fertility of spermatozoa. A high percentage of progressively motile spermatozoa was obtained from epididymis stored for 8 d at 5 degrees C in mineral oil (78.3%), covered with body fat (80.0%), or stored in the intact body of the euthanized donor animal (77.5%). Fertilized eggs (6.4% fertilization rate) were obtained by IVF using spermatozoa that had been stored in mineral oil at 5 degrees C for at least 8 d, and offspring were obtained from 77.5% of transferred eggs that were fertilized by spermatozoa stored for 2 d. These methods inhibited moisture loss from the preserved epididymal spermatozoa, thereby allowing spermatozoa to be stored for a few days without loss of either motility or fertility. These methods make possible such wide-ranging applications as the long-distance transport of epididymis spermatozoa. While in storage at 5 degrees C, the tail of each recovered spermatozoon was bent midway along the tail, possibly owing to damage to the plasma membranes and due to the spermatozoa's hardening in the phospholipid by exposure to the low temperature.

Animals↗
PubMed2001

B7-DC, a new dendritic cell molecule with potent costimulatory properties for T cells.

Dendritic cells (DCs), unique antigen-presenting cells (APCs) with potent T cell stimulatory capacity, direct the activation and differentiation of T cells by providing costimulatory signals. As such, they are critical regulators of both natural and vaccine-induced immune responses. A new B7 family member, B7-DC, whose expression is highly restricted to DCs, was identified among a library of genes differentially expressed between DCs and activated macrophages. B7-DC fails to bind the B7.1/2 receptors CD28 and cytotoxic T lymphocyte-associated antigen (CTLA)-4, but does bind PD-1, a receptor for B7-H1/PD-L1. B7-DC costimulates T cell proliferation more efficiently than B7.1 and induces a distinct pattern of lymphokine secretion. In particular, B7-DC strongly costimulates interferon gamma but not interleukin (IL)-4 or IL-10 production from isolated naive T cells. These properties of B7-DC may account for some of the unique activity of DCs, such as their ability to initiate potent T helper cell type 1 responses.

Amino Acid Sequence↗