Biomedical subjects

H Tsuchiya

Publications and source records attributed to H Tsuchiya.

At least 37 records · Page 2Linked to original sources

PubMed2001

Stereospecificity in membrane effects of catechins.

Green tea catechins consisting of catechin stereoisomers and their derivatives have been suggested to show biological activities through the interactions with cellular membranes. Their effects on membrane fluidity were comparatively studied by measuring fluorescence polarization of liposomal membranes prepared with phospholipids and cholesterol. All catechin stereoisomers reduced membrane fluidity by acting on the hydrophilic and hydrophobic regions of membrane bilayers at 20-500 microM. Both epicatechins in a cis form were more effective for reducing membrane fluidity than both catechins in a trans form. (-)-Epicatechin, (+)-epicatechin, (-)-catechin and (+)-catechin reduced membrane fluidity in increasing order of intensity. Such difference between optical isomers was increased by chiral cholesterol added to membrane lipids. In reversed-phase chromatographic evaluation, (-)-epicatechin and (+)-epicatechin were more hydrophobic than (-)-catechin and (+)-catechin, although hydrophobicity was not distinguishable between optical isomers. Stereospecificity in the membrane effects of catechin stereoisomers may be induced by the different hydrophobicity of geometrical isomers and the chirality of membrane lipid components. At lower concentrations (5-100 microM), (-)-epigallocatechin gallate and (-)-epicatechin gallate reduced membrane fluidity more significantly than (-)-epicatechin, suggesting that the intensive membrane effect contributes to the potent medicinal utility of (-)-epigallocatechin gallate.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2001

Anatomical aspects of biopsy of the proximal fibula.

The relationship between the peroneal nerves and the anatomical structures near the fibular head were studied in 20 cadavers. It was the purpose to define the boundaries of a "safe" area when performing a biopsy of the fibular head. The distances between the proximal end of the fibular head and the deep peroneal nerve (26+/-0.32 mm) and the intermuscular septum (15+/-0.19 mm) were measured, as well as the angle between the deep peroneal nerve and the fibula as seen in the A-P view (23.5+/-3.5 degrees). We considered that biopsies should be performed with an anterolateral approach in the safe area formed by the fibular head and the deep peroneal nerve in the anterior compartment.

Biopsy↗

PubMed2001

Presacral tumor associated with the Currarino triad in an adolescent.

A 17-year-old woman presented with pain over the sacral region. Plain radiographs of the sacrum demonstrated a bony deformity of the sacrococcygeal region in the shape of a scimitar. Magnetic resonance imaging showed a cystic mass of the presacral region which appeared to be continuous with the dural sac. An anteroposterior view myelogram revealed caudal elongation of the dural sac, and on the lateral view it was recognized as an anterior meningocele. At surgery, we confirmed a connection between the presacral mass and the rectum. In light of the combination of a sacral bony deformity, presacral mass including meningocele, and mass-rectum connection, we made the diagnosis of the Currarino triad, which is a rare complex of congenital caudal anomalies. The patient underwent excision of the presacral mass. Histologic examination of the resected specimen revealed features of an epidermoid cyst.

Abnormalities, Multiple↗

PubMed2001

Bilateral symmetrical cysts in the upper tibiae in a skeletally mature patient: might they be simple bone cysts?

A 55-year-old Japanese woman presented with right knee pain of 1-month duration. Radiological studies revealed bilateral mild osteoarthritic changes in the medial knee joint compartment and symmetrical cysts in the upper tibial metaphyses, extending to the epiphyses. Intraosseous ganglion was considered the most probable diagnosis. However, intraoperatively, serous fluid-filled cavities were recognized; these were curetted and filled with hydroxyapatite granules. Histopathological examination of the cyst wall revealed thin fibrous tissue formed of collagen fibers without a lining cell layer, with scattered lymphocytes, histiocytes, irregular masses of fibrin-like material, and periosteal osteocartilagenous callus formation; a picture compatible with simple bone cysts. Bilateral symmetrical cysts of the upper tibial metaphyses extending to the epiphyses are extremely rare. A literature review revealed that the age incidence, and bony locations of multiple and epiphyseal simple bone cysts are atypical in relation to the classic metaphyseal simple bone cysts. Also, multiple and epiphyseal simple bone cysts have a better prognosis than the classic metaphyseal ones. Four clinicoanatomic varieties of simple bone cysts are recognized; classic metaphyseal, nontubular, epiphyseal, and multiple.

Bone Cysts↗

PubMed2001

Tumor growth potential after tumoral and instrumental contamination: an in-vivo comparative study of T-saw, Gigli saw, and scalpel.

In the field of spinal tumors, intralesional tumor cutting is sometimes inevitable. The purpose of this study was to compare the potential for tumor growth after intralesional cutting by T-saw, Gigli saw, and scalpel. Tumors, prepared by the subcutaneous injection of human HT 1080 fibrosarcoma cells in nude mice, were harvested and cut with a T-saw, Gigli saw, or scalpel. A 3-cm wound was created in the skin on the back in another group of nude mice. The cut surface of the tumor was rubbed for 10 s against the subcutaneous tissue in this second group of nude mice. In the same manner, the instrument used for tumor cutting was rubbed against the subcutaneous tissue in the 3-cm wound in the back of a third group of nude mice for 10 s. Other instruments used for tumor cutting were immediately washed in culture medium, and the total number of tumor cells was counted. Tumor blocks and single-cell suspensions prepared from tumor tissues of the same weight were inoculated and injected into a fourth group of nude mice. The incidence of tumor growth after the rubbing of the subcutaneous tissue with the tumor surface cut with a T-saw, Gigli saw, and scalpel was 16.7%, 50.0%, and 33.3%, respectively. The corresponding figures after the rubbing of the subcutaneous tissue with a T-saw, Gigli saw, and scalpel was 16.7%, 33.3%, and 33.3%, respectively. The mean numbers of tumor cells attached to the T-saw, Gigli saw, and scalpel were 1.88 x 105, 5.02 x 105, and 4.92 x 105, respectively. Finally, the incidence of tumor growth after the inoculation of tumor blocks and single-cell suspensions was 100% and 77.8%, respectively. These findings show that tumor recurrence is less likely after intralesional tumor cutting with a T-saw than after such cutting with a Gigli saw or scalpel.

Animals↗

PubMed2001

Ankle arthrodesis and tibial lengthening for congenital sensory neuropathy with anhidrosis.

This report describes a patient with congenital sensory neuropathy with anhidrosis (CSNA) with destructive arthropathy of the left ankle joint that was treated with ankle arthrodesis and tibial lengthening, using an Ilizarov external fixator. The fusion at the ankle joint was successful, but, at the lengthening site, loosening of the apparatus occurred and formation and maturation of the distracted callus were delayed. Intramedullary nailing was used after the removal of the external fixator, and a low-intensity ultrasound device was employed, after which the distracted callus matured gradually. During the maturation period, the patient's dysplastic right hip joint was destroyed, without the occurrence of any severe symptoms. Distraction osteogenesis in patients with CSNA may lead to good results if rigid fixation, nonweight-bearing (i.e., adequate rest), and appropriate biological stimulation can be employed.

Adult↗

PubMed2001

Biphasic membrane effects of capsaicin, an active component in Capsicum species.

Capsaicin, an active component in Capsicum species, not only stimulates sensory afferent neurons but also inhibits bacterial growth and platelet aggregation. To address the pharmacological mechanism of non-neuronal actions, the effects of capsaicin and its structural analog (N-vanillylnonanamide) on membrane fluidity were studied by measuring fluorescence polarization of liposomes prepared with different phospholipids and cholesterol. Capsaicin and the analog changed membrane fluidity over the concentration range of 50-500 microM differentially with varying concentrations and membrane lipid composition. They showed biphasic effects on 100 mol% 1-palmitoyl-2-oleoylphosphatidylcholine liposomes and 40 mol% cholesterol-containing 1-palmitoyl-2-oleoylphosphatidylcholine liposomes to fluidize and rigidify both liposomal membranes at low and high concentrations, respectively. Changes in membrane fluidity occurred at concentrations corresponding to their reported antibacterial and antiplatelet concentrations. Antibacterial (geraniol and lidocaine) and antiplatelet reference compounds (4-ethylphenol and benzyl alcohol) concentration-dependently fluidized membranes, while not showing biphasic effects. Comparing the potency to fluidize membranes, capsaicin was almost comparable to geraniol and 4-ethylphenol, and more active than lidocaine and benzyl alcohol. The membrane effects of capsaicinoids are responsible for their non-neuronal antibacterial and antiplatelet actions, although they are not the simple membrane fluidizers.

Capsaicin↗

PubMed2001

Characterization of platelet-derived growth factor-induced p38 mitogen-activated protein kinase activation in vascular smooth muscle cells.

BACKGROUND: The mitogen-activated protein (MAP) kinase super-family plays a crucial role in cell growth and differentiation and even in programmed cell death in response to diverse extracellular stimuli. The platelet-derived growth factor (PDGF)-BB is well known to promote the proliferation of vascular smooth muscle cells (VSMC) via extracellular-regulated protein kinases (ERKs), leading to the development of cardiovascular diseases. However, it has not yet been clarified whether PDGFs that include other isoforms can activate the other parallel signal transduction pathways, c-jun NH2-terminal protein kinase (JNK) and p38 MAP kinase (p38), in VSMC. In this study, we investigated the effect of PDGFs on p38 activation in cultured rat VSMC. MATERIALS AND METHODS: After stimulation by PDGFs with SB-203580 or PD-98059, the cells were solubilized, and the expressions of MAP kinases, MAP kinase kinases (MKKs), phosphorylated DNA-binding proteins, and cyclooxigenases (COXs) were examined by immunoblot analysis. RESULTS: PDGFs activated p38 phosphorylation dose-dependently, and the phosphorylations were specifically inhibited by SB-203580 but not by PD-98059. PDGFs also activated the phosphorylation of MKK 3/MKK 6 but not that of either stress-activated protein kinase/ERK kinase or JNK. PDGFs affected the activation of a cyclic AMP response-element binding protein, which was inhibited by SB-203580. However, the activating transcription factor-2 was not activated by PDGFs. Interestingly, the stimulation of PDGFs for 72 h enhanced the level of COX-2, and these levels were decreased by SB-203580. CONCLUSION: These results have clarified that PDGFs activate the p38 cascade via an MKK 3/6 pathway, independently of the ERK cascade, and subsequently regulate the level of COX-2 in rat VSMC, providing that PDGFs influence the inflammatory process in the vascular wall.

Activating Transcription Factor 2↗

PubMed2001

Structure-specific membrane-fluidizing effect of propofol.

1. While recent studies about the pharmacological mechanism of the intravenous anaesthetic propofol (2,6-diisopropylphenol) have focused on its interaction with functional proteins, there is the possibility that propofol alters membrane properties to produce anaesthesia. In the present study, the structure-specific effects of propofol on liposomal model membranes were studied. 2. The effect of propofol on the phase transition of membrane phospholipid was analysed spectrophotometrically using 1,2-dipalmitoyl-L-alpha-phosphatidylcholine liposomes. Propofol (50-200 micromol/L) lowered the phase transition temperature to fluidize membranes. 3. Membrane fluidization was also analysed by measuring fluorescence polarization of liposomes consisting of 1,2- dipalmitoyl-L-alpha-phosphatidylcholine, 1-palmitoyl-2-oleoyl-L- alpha-phosphatidylcholine and cholesterol with different probes. Propofol fluidized all liposomal membranes in the concentration range 5-500 micromol/L by acting on both the inner and outer layers of the membranes. 4. The membrane effects of propofol were compared with those of 2,6-dialkylphenols, 1,3-dialkylbenzenes, 2-alkylphenols and alkylbenzenes. Although the membrane-fluidizing effects were shared by a series of structural analogues, propofol was most effective in fluidizing membranes, especially liposomal membranes consisting of 20 mol% cholesterol and 80 mol% 1-palmitoyl-2-oleoyl-L-alpha-phosphatidylcholine. 5. Lipophilicity was compared between propofol and its structural analogues using their capacity factors, determined by reverse-phase high-performance liquid chromatography. The potency of propofol to fluidize membranes was much greater than anticipated from its lipophilicity. 6. At 0.125-1.0 micromol/L, almost corresponding to clinically relevant concentrations, propofol significantly enhanced membrane fluidity of cholesterol-containing 1-palmitoyl-2-oleoyl-L-alpha-phosphatidylcholine liposomes. 7. These results indicate that propofol fluidizes membranes in a structure-specific manner through an interaction with membrane lipids. Such a membrane effect may be responsible for the mode of anaesthetic action of propofol.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2001

Characterization of an inhibitory effect of pioglitazone on balloon-injured vascular smooth muscle cell growth.

This study investigates whether pioglitazone could suppress an atherogenic process such as balloon-injured carotid intimal thickening and the proliferation of vascular smooth muscle cells (VSMC). We first examined the effect of pioglitazone to determine whether it could suppress intimal thickening induced by balloon catheterization in Sprague-Dawley rats. After 14 days postcatheterization in the left common carotid artery, the neointimal layers were completely occupied by proliferated VSMC, and the area ratio of neointima to media treated with 10 mg/kg/d of pioglitazone was significantly decreased to 57%. Next, we evaluated the effect of pioglitazone on the proliferation of rat cultured VSMC. Piogliotazone dose-dependently decreased the values of DNA synthesis, total cellular protein content, phosphorylations of extracellular signal-regulated protein kinase 1/2 and mitogen-activated protein kinase kinase 1/2, and proliferative cell nuclear antigen in VSMC. Pioglitazone also inhibited the phosphorylation of Pyk2. We conclude that pioglitazone itself could be effective for suppressing the growth of VSMC and consequent carotid intimal thickening.

Animals↗

PubMed2001

Cold preservation of rat pancreatic islets just above the freezing point using University of Wisconsin solution.

AIMS: To confirm whether rat islets stored at a temperature just above the freezing point using University of Wisconsin (UW) solution would remain viable for the short term. METHODOLOGY: Rat islets were stored for 24 hours in UW solution, either at 4 degrees C or at -0.6 degrees C (just above the specific freezing point of the UW solution). After cold storage, the islets were assessed for in vitro viability by static incubation and for in vivo viability by a transplantation study. One thousand islets preserved under different conditions were injected intraportally into a streptozotocin-induced diabetic rat as an isograft. Four weeks after the transplantation, an intravenous glucose tolerance test was performed. RESULTS: Islets stored at -0.6 degrees C showed higher insulin secretion rates than those stored at 4 degrees C on a static challenge. The interval from transplantation to the achievement of normoglycemia was also shorter in the -0.6 degrees C group than in the 4 degrees C group. After islet transplantation, the daily nonfasting plasma glucose concentration was higher in the 4 degrees C group than in the -0.6 degrees C group. When compared with the 4 degrees C group, the -0.6 degrees C group showed lower blood glucose values during all investigational periods on an intravenous glucose tolerance test. CONCLUSION: Islet preservation at -0.6 degrees C using UW solution is more advantageous for short term.

Animals↗

PubMed2001

Calcitonin induces IL-6 production via both PKA and PKC pathways in the pituitary folliculo-stellate cell line.

It has been demonstrated that calcitonin-binding sites are present in a variety of tissue types, including in the pituitary gland. Interleukin-6 (IL-6) is also produced in the pituitary and it regulates the secretion of various hormones. In this study, we examined the expression of the calcitonin receptor and the mechanism of IL-6 production induced by calcitonin in the pituitary folliculo-stellate cell line (TtT/GF). The mRNA of calcitonin receptor subtype C1a, but not that of C1b, was detected by RT-PCR in TtT/GF cells and in the normal mouse pituitary. Calcitonin increased cAMP accumulation and IL-6 production in a concentration-dependent manner in TtT/GF cells. As calcitonin activates the PKA and PKC pathways, we investigated the contributions of PKA and PKC to IL-6 production. IL-6 production was only slightly increased by either 8-bromo-cAMP (1 mM) or phorbol 12-myristate 13-acetate (100 nM) alone. However, IL-6 was synergistically induced in the presence of both 8-bromo-cAMP (1 mM) and phorbol 12myristate 13-acetate (100 nM). Furthermore, calcitonin-induced IL-6 production was completely suppressed by H-89 (PKA inhibitor) or GF109203X (PKC inhibitor), indicating that the activation of both PKA and PKC is necessary for calcitonin-induced IL-6 production. On the other hand, pertussis toxin (G(i)/G(o) signaling inhibitor) treatment achieved an approximately 9-fold increase in calcitonin-induced IL-6 production. These results show that calcitonin-stimulated IL-6 production is mediated via both PKA- and PKC-signaling pathways, whereas calcitonin also suppresses IL-6 production by activating G(i)/G(o) proteins in folliculo-stellate cells.

Animals↗

PubMed2001

Biphasic effects of acetaldehyde-biogenic amine condensation products on membrane fluidity.

I have studied the effects of four acetaldehyde-biogenic amine condensation products on membrane fluidity of liposomes, consisting of 1-palmitoyl-2-oleoylphosphatidylcholine and cholesterol, by measuring fluorescence polarization using different probes. The condensation products were 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC), 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (6-OH-MTBC), 3-carboxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (3-C-MTBC) and 6,7-dihydroxy-1-methyl-1,2,3,4-tetrahydroisoquinoline (salsolinol). They changed the fluidity of the hydrophobic and hydrophilic regions of liposomal membranes at micromolar levels almost corresponding to their antibacterial and antiplatelet concentrations, but their membrane effects varied by structure, concentration and membrane lipid composition. MTBC and salsolinol showed biphasic effects on the inner layers of membranes to enhance the fluidity at 250-1000 microM and reduce the fluidity at 50-100 microM, whereas both of them fluidized the outer layers of the membranes. 3-C-MTBC concentration-dependently fluidized both layers of membranes. 6-OH-MTBC most weakly enhanced and reduced the fluidity of the outer and inner layers, respectively. The membrane effect of MTBC was the greatest of the four condensation products. MTBC (50-1000 nM) significantly reduced the fluidity by exclusively acting on the membrane core, but was less effective in fluidizing the membrane surface. However, the others were not active at low nanomolar levels. The membrane effects may be partly responsible for the antibacterial and antiplatelet actions of the acetaldehyde-biogenic amine condensation products, although they do not appear to be simple membrane fluidizers.

Acetaldehyde↗

PubMed2001

Short-term preservation of mouse oocytes at 5 degrees C.

The temporary preservation of oocytes without freezing would be useful for some experiments. ICR mouse oocytes were kept in a preservation medium under mineral oil for 1, 2, 3, 4 or 7 days at 5 degrees C, and 1 or 2 days at 37 degrees C. In vitro fertilization was attempted on oocytes rinsed with TYH medium after preservation. More than 70% of morphologically normal oocytes were recovered from each preservation group. Fertilization rates of oocytes preserved for 1, 2, 3, 4 or 7 days at 5 degrees C were 69.9, 66.5, 45.3, 26.7 and 8.8% respectively. Fertilization rates of oocytes preserved for 1 or 2 days at 37 degrees C were 9.6 and 1.6%, respectively. Preservation of oocytes at 5 degrees C has some capability as a method of short-term storage without freezing.

Animals↗

PubMed2001

Gitelman's syndrome first diagnosed as Bartter's syndrome.

A 29-year-old man, who had been treated with potassium, spironolactone and indomethacin for over 9 years, was admitted because of nausea, vomiting, diarrhea and tetany manifestation. At the age of 20, he had been diagnosed as having Bartter's syndrome according to the criteria of the Japanese Ministry of Health and Welfare. Findings on admission were hypokalemia, hypomagnesemia and hypocalciuria. Renal distal fractional reabsorption rates of sodium, chloride and calcium were markedly decreased by administration of furosemide but there was no obvious change with administration of thiazide. These findings indicate that the patient had Gitelman's syndrome rather than Bartter's syndrome.

Adult↗

PubMed2000

Regeneration of lymphatic vessels and lipometabolism in an experimental rat model of extensive dissection of the abdominal periaortic lymphatic vessels and lymph nodes.

The present study was conducted to analyze the regeneration of lymphatic vessels and lipometabolism in an experimental rat model of extensive dissection of the abdominal periaortic lymphatic vessels and lymph nodes from the renal artery to the mesenteric and celiac artery. Findings showing the regeneration of mesenteric lymphatic vessels were classified as complete, incomplete, or no regeneration. The incomplete regeneration of fine irregular lymphatic vessels was observed in all rats, 2 and 3 weeks postoperatively. At the same time, triglyceride (TG) was found to be significantly lower (P < 0.05) in the rats that were given extensive dissection than in the control group, due to chylomicron blockade after lymphatic dissection. The TG recovered to within the normal range around 4 weeks postoperatively following the growth of fine regenerated lymphatic vessels or collateral route formation.

Animals↗

PubMed2000

Extraskeletal myxoid chondrosarcoma with multiple skeletal metastases.

Pulmonary metastases are not unusual in extraskeletal myxoid chondrosarcoma; however, only two patients have been reported with multiple bony metastases. We report here one patient with extraskeletal myxoid chondrosarcoma associated with lung and multiple bony metastases. After chemotherapy, the primary lesion was resected, but lung and multiple bony metastases were found 20 months later. The bony metastases were in the right femur, right humerus, and at multiple vertebral levels. Because of a pathologic fracture of the right femur, the metastases in the right femur and right humerus were surgically stabilized. After chemotherapy, the lung metastases were resected, and those in the vertebral bodies were treated with radiotherapy.

Bone Neoplasms↗

PubMed2000

Impaired novelty detection and frontal lobe dysfunction in Parkinson's disease.

Recent evidence suggests that the frontal lobe plays an important role in an orienting response to novel events, and that frontal lobe dysfunction is linked to attentional and cognitive deficits in Parkinson's disease (PD). We tested the hypothesis that the neural network involved in novelty detection may be impaired in PD patients by studying event-related brain potentials to target and novel stimuli and their correlation to performance in neuropsychological tests in non-demented PD patients. The PD patients showed prolonged P3 latency to novel stimuli compared with age-matched controls, whereas their P3 latency to target stimuli was not different from that in controls. The PD patients also manifested amplitude reduction and less habituation of the P3 to novel stimuli over frontal scalp sites compared with controls. The prolonged latency and frontal reduction of novelty P3 correlated with a poor performance in the Wisconsin Card Sorting Test. These results suggest that the orienting response of PD patients to novel events is impaired and that recording novelty P3 might provide a neurophysiological and quantitative measure of attentional and cognitive deficits linked to the frontal lobe in non-demented PD patients.

Adult↗