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Biomedical subjects

Y Hattori

Publications and source records attributed to Y Hattori.

At least 19 recordsLinked to original sources
PubMed2006

Arthoscopic diagnosis of partial scapholunate ligament tears as a cause of radial sided wrist pain in patients with inconclusive x-ray and MRI findings.

To clarify the pathology of radial-sided wrist pain with inconclusive X-ray and MRI findings, we performed arthroscopic examinations of 11 wrists in 10 patients. Physical examination and various image investigations could not identify the cause of the pain. Arthroscopy revealed partial to complete tears of the scapho-lunate interosseous ligament and synovitis and/or chondral bone defects at the scaphotrapezio-trapezoidal joint in all 11 wrists. Surgical procedures consisted of eight simple synovectomies, two ligament reconstructions and one percutaneous pinning. Pain relief was achieved in 10 wrists. One wrist which had a simple synovectomy did not recover, so underwent secondary scaphotrapezio-trapezoidal fusion. In conclusion, we found that various degrees of scapholunate interosseous ligament tear and scaphotrapezio-trapezoidal joint osteoarthritis were the main causes of radial-sided wrist pain with inconclusive X-ray and simple MRI findings.

Humans↗
PubMed2006

Functional properties and regional differences of human masseter motor units related to three-dimensional bite force.

The aim of this study was to estimate numerically the properties of masseter motor units (MUs) in relation to bite force magnitude and direction three-dimensionally and to confirm the hypothesis that the properties differ between different parts of the muscle by means of simultaneous recording of MU activity along with the MU location and three-dimensional (3D) bite force. The MU activity of the right masseter of four healthy men was recorded using a monopolar needle electrode in combination with a surface reference electrode. The location of the needle electrode was estimated stereotactically with the aid of magnetic resonance images and a reference plate. The magnitude and direction of the bite force was recorded with a custom-made 3D bite force transducer. The recorded bite force was displayed on a signal processor, which enabled the participant to adjust the direction and magnitude of the force. The activities of 65 masseter MUs were recorded. Each MU had specific ranges of bite force magnitude and direction (firing range: FR) and an optimum direction for recruitment (minimum firing threshold: MFT). There was a significant negative correlation between MFT and FR width. There were functional differences in MU properties between the superficial and deep masseter and between the superficial layer and deep layer in the superficial masseter. These results indicate that the contribution of human masseter motor units to bite force production is heterogeneous within the muscle.

Action Potentials↗
PubMed2005

Angiotensin-II-induced oxidative stress elicits hypoadiponectinaemia in rats.

AIMS/HYPOTHESIS: Hypertension, endothelial dysfunction and insulin resistance are associated conditions that share oxidative stress and vascular inflammation as common features. Adiponectin is an abundant plasma adipokine that plays a physiological role in modulating lipid metabolism and exerts a potent anti-inflammatory activity. We hypothesised that adiponectin levels decrease in response to oxidative stress and that this may promote the development of hypertension, endothelial dysfunction and insulin resistance. METHODS: Rats were infused with angiotensin II (AngII) or its vehicle, either alone or in combination with tempo1 (4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl), a membrane-permeable metal-independent superoxide dismutase mimetic, or tetrahydrobiopterin (BH4), one of the most potent naturally occurring reducing agents and an essential cofactor for nitric oxide synthase activity. Heart rate, systolic blood pressure, body weight and serum levels of adiponectin were measured on day 7 of treatment, and then the animals were killed. Vessel tone and superoxide production were measured ex vivo in thoracic vascular rings. The expression of adiponectin mRNA in adipose tissue was assessed by Northern blotting, and in 3T3-L1 adipocytes exposed to H2O2 by real-time PCR. The expression of NAD(P)H oxidase subunit mRNAs in the rats was assessed by RT-PCR and real-time PCR. RESULTS: Hypertension and endothelial dysfunction were induced in rats by infusion of AngII and reversed by administration of tempol. Plasma concentrations of adiponectin and adipose tissue levels of adiponectin mRNA were decreased in AngII-infused rats, and this effect was prevented by cotreatment with tempol or BH4. The production of superoxide anions (O2-) was significantly increased in the aortae of AngII-treated rats, and this increase was prevented by the administration of tempol or BH4. Levels of mRNAs that encode NAD(P)H oxidase components, including p22phox, gp91phox, p47phox and Rac1, were similarly increased in adipose tissue, aortae and hearts of AngII-infused rats. Cotreatment of rats with tempol or BH4 reversed AngII-induced increases in NAD(P)H oxidase subunit mRNAs. Fully differentiated 3T3-L1 adipocytes, also exhibited diminished adiponectin mRNA levels when exposed to low concentrations of H2O2. CONCLUSIONS/INTERPRETATION: Our results demonstrate that AngII-induced oxidative stress and endothelial dysfunction are accompanied by a decrease in adiponectin gene expression. Since antioxidants were observed to prevent the actions of AngII, and H2O2 on its own suppressed adiponectin expression, we conclude that adiponectin gene expression is negatively modulated by oxidative stress. Plasma adiponectin levels may provide a useful indicator of oxidative stress in vivo, and suppressed levels may contribute to the proinflammatory and metabolic derangements associated with type 2 diabetes, coronary artery disease and the metabolic syndrome.

Adiponectin↗
PubMed2005

Sclerosing therapy of internal hemorrhoids with a novel sclerosing agent. Comparison with ligation and excision.

BACKGROUND AND AIMS: Patients with prolapsing internal hemorrhoids were treated with a novel sclerosing agent (OC-108), and the results were compared with surgery of ligation and excision. PATIENTS AND METHODS: This study included 20 years or older patients with prolapsing internal hemorrhoids who visited ten medical institutions in Japan from October 2000 to October 2002. Investigation on surgery was also performed. RESULTS: Comparing OC-108 and surgery in patients with third- and fourth-degree internal hemorrhoids according to the Goligher's classification, for which surgery has been generally indicated, at 28 days after treatment, the disappearance rate of prolapse was similar between OC-108 and surgery, 94% (75/80 patients) and 99% (84/85 patients), respectively. The 1-year recurrence rate was 16% (12/73 patients) in the OC-108 group, and this value was satisfactory because of its less invasive nature while it was more or less higher compared with 2% (2/81 patients) in the surgery group. The incidences of pain and bleeding were lower in the OC-108 group. CONCLUSIONS: OC-108 is a useful alternative treatment for hemorrhoids.

Adult↗
PubMed2005

Immunosuppressive effect of long-term drainage of thoracic duct on immunological memory in adult thymectomized rats.

Profound reduction of the recirculating lymphocyte pool using thoracic duct drainage (TDD), a method developed by Gowans et al, has been shown to be of limited immunosuppressive value when applied in experimental as well as in clinical settings across major histocompatibility antigen complex (MHC) differences. This limitation is due to the observation that animals, in particular mice, are normally not able to have the drainage last longer than 8 to 10 days. However, using a simple modification of TDD, we have established a long-term TDD method, ie, more than 20 days. Combining this long-term TDD with adult thymectomy, we have examined the life span of naive and memory T cells specific for the minor histocompatibility antigen H-Y in female lewis rats. Furthermore, we demonstrated that memory T cells specific for the H-Y antigen do not appear to be recirculating lymphocytes.

Animals↗
PubMed2005

A heteroplasmic mitochondrial DNA 3310 mutation in the ND1 gene in a patient with type 2 diabetes, hypertrophic cardiomyopathy, and mental retardation.

A mentally retarded 57-year-old Japanese man with maternally-inherited type 2 diabetes was found to have hypertrophic cardiomyopathy (HCM) that was associated with pathological changes in the myocardial mitochondria. The mitochondrial DNA (mtDNA) of this patient was examined and a C3310 T mutation was found in the ND1 gene, which resulted in the substitution of serine for proline. The normal 3310 mtDNA band could not be detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in mtDNA from his myocardium, pancreas, cerebral tissue, skeletal muscle, and lymphocytes. However two clones sequenced from his pancreatic tissue did not show this C3310 T mutation while forty-eight did. Mitochondria isolated from the lymphocytes of his two sisters also had this mutation. mtDNA point mutations in the ND1 gene region reported thus far have been mostly homoplasmic. However, the C3310 T point mutation that was found in this patient was heteroplasmic, which is a high level of mutation and may represent the pathogenic gene that was responsible for causing mitochondrial disease.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Shell model for rotating turbulence.

A modified shell model for rotating turbulence is proposed. The effect of rotation is introduced by a randomized linear term. Randomization is shown to be important in correctly modeling the rotation effect. Numerical simulation shows that the exponent of the energy spectrum in the inertial range changes from -5/3 to -2 as rotation rate increases. The mechanism behind this change is explained by weak turbulence theory and supported by numerical results.

Journal Article↗
PubMed2004

Complete replacement of tracheal epithelia by the host promotes spontaneous acceptance of orthotopic tracheal allografts in rats.

BACKGROUND: Tracheal immunogenicity has been controversial. Although replacement of allotracheal epithelia by the host epithelia has been reported in rat orthotopic tracheal grafting, the immunological effect of epithelial replacement is still uncertain. METHODS: We performed orthotopic tracheal grafting of nine cartilage rings in the following groups: 1, Lewis --> Lewis (n = 30); 2, ACI --> DA (n = 25); 3, Lewis --> F344 (n = 23); 4-A, DA --> Lewis (n = 41); 4-B, DA --> Lewis with tacrolimus therapy (1 mg/kg/d for 10 days) starting from the day of the operation (n = 31); 4-C, retransplantation of DA allografts to secondary naive Lewis rats 10 or 15 days after primary grafting (n = 11); 4-D, DA --> Lewis with tacrolimus therapy starting from postoperative day 10 (n = 6). Survival times and histopathology were assessed. Epithelial replacement was evaluated by immunohistochemistry. RESULTS: All rats survived in groups 1, 2, and 3. Even in the fully histoincompatible group 4-A, survival ratio on day 120 was 15%. Epithelial replacement was in progress on day 10 in this group. However, all tacrolimus-treated rats died by day 54 and epithelial replacement did not occur on days 30 and 50 in group 4-B. In group 4-C, retransplantation after complete epithelial replacement increased the long-surviving rats. In group 4-D, all rats receiving tacrolimus therapy after complete epithelial replacement survived over 120 days. CONCLUSIONS: These results suggest that complete replacement of tracheal epithelia by the host promotes spontaneous acceptance of orthotopic tracheal allografts in rats.

Animals↗
PubMed2004

Characterization of vascular endothelial growth factor (VEGF) in the uterine cervix over pregnancy: effects of denervation and implications for cervical ripening.

Bilateral neurectomy of the pelvic nerve (BLPN) that carries uterine cervix-related sensory nerves induces dystocia, and administration of its vasoactive neuropeptides induces changes in the cervical microvasculature, resembling those that occur in the ripening cervix. This study was designed to test the hypothesis that (a) the cervix of pregnant rats expresses vascular endothelial growth factor (VEGF) and components of the angiogenic signaling pathway [VEGF receptors (Flt-1, KDR), activity of protein kinase B, Akt (phosphorylated Akt), and endothelial nitric oxide synthase (eNOS)] and von Willebrand Factor (vWF) and that these molecules undergo changes with pregnancy, and (b) bilateral pelvic neurectomy (BLPN) alters levels of VEGF concentration in the cervix. Using RT-PCR and sequencing, two VEGF isoforms, 120 and 164, were identified in the rat cervix. VEGF, VEGF receptor-1 (Flt-1), eNOS, and vWF immunoreactivities (ir) were localized in the microvasculature of cervical stroma. Their protein levels increased during pregnancy but decreased to control levels by 2 days postpartum. VEGF receptor-2 (KDR)-ir was confined to the epithelium of the endocervix. BLPN downregulated levels of VEGF by a third. Therefore, the components of the angiogenic signaling pathway are expressed in the cervix and change over pregnancy. Furthermore, angiogenic and sensory neuronal factors may be important in regulating the dynamic microvasculature in the ripening cervix and may subsequently play a role in cervical ripening and the birth process.

Animals↗
PubMed2004

Aromatase is abundantly expressed by neonatal rat penis but downregulated in adulthood.

Although synthesis of estrogen by male gonads has been well documented for over half a century, it is only recently that the role of estrogen in male reproductive events has gained appreciation. We recently reported abundant expression of estrogen receptor (ER)-alpha and -beta in different cell types of the rat penis, whose levels diminished with advancing age. The present study, which builds on data from the ER study, was designed to determine whether the penis is capable of generating its own local estrogen by examining evidence of the expression of aromatase, a microsomal enzymatic complex which irreversibly converts androgens to estrogens, using immunohistochemistry, Western blotting, in situ hybridization and real-time PCR analyses. Secondly, the effects of sex steroid hormones on penile aromatase were examined. Discrete aromatase immunoreactive cells were localized in primordial corpus cavernosum, corpus spongiosus and os penis, blood vessels and sensory corpuscle of glans penis. In situ hybridization signals corresponded with immunohistochemical findings. Western blot, enzyme immunoassay and real-time PCR analyses of rat penile samples revealed an age-dependent expression of aromatase and estrogen, with levels at week 1 almost resembling those of the ovary, but they decreased sharply by week 8, and decreased further by week 35. This expression pattern was strikingly similar to that of ER-alpha reported previously. Testosterone and diethylstilbesterol administered prenatally upregulate levels of aromatase mRNA and protein, and estrogen postnatally. Dihydrotestosterone upregulated aromatase mRNA and protein, but not estrogen. We conclude that estrogen acts via ER in a paracrine and/or autocrine manner to regulate penile events, particularly during development, and that estrogen synthesis is regulated by estrogen and androgens.

Animals↗
PubMed2004

Choline acetyltransferase activity and evoked spinal cord potentials for diagnosis of brachial plexus injury.

The purpose of this study is to investigate the diagnostic value of evoked spinal cord potentials (ESCPs) and choline acetyltransferase (CAT) activity during exploration of injuries to the brachial plexus. We assessed 25 spinal roots in 19 patients. The results of the two investigations were consistent in all except two roots. Although assessment of ESCPs is easy and quick, it mainly records the nerve potentials along the sensory pathway. Although measurement of CAT activity needs a specimen of the nerve and the availability of a radioisotope laboratory, it gives direct information regarding the motor function of ventral spinal roots. These two techniques should be complementary to each other in order to achieve a more accurate diagnosis.

Adolescent↗
PubMed2004

Effect of cationic charge on receptor-mediated transfection using mannosylated cationic liposome/plasmid DNA complexes following the intravenous administration in mice.

The purpose of this study was to evaluate the effect of cationic charge of complexes after intravenous administration of cholesten-5-yloxy-N-[4-[(1-imino-2-D-thiomannosyl-ethyl)amino]butyl]formamide (Man-C4-Chol) containing cationic liposomes/pDNA complexes in mice. Transfection efficiency after intravenous administration of complex at a charge ratio (- : +) of 1.0:2.3 and/or 1.0:3.1 in liver and spleen expressing a mannose receptor on the cell surface were higher than those in lung. When complexes were formed at a charge ratio (- : +) of 1.0:4.7, on the other hand, transfection efficiency in the lung was highest, suggesting a non-specific interaction. Although asialoglycoprotein receptors are expressed on hepatocytes, a liver-selective gene transfection was not achieved by the intravenous administration of pDNA complexed with cholesten-5-yloxy-N-[4-[(1-imino-2-D-thiogalactosyl-ethyl)-amino]butyl]formamide (Gal-C4-Chol)/DOPE liposomes at a charge ratio (- : +) of 1.0 : 2.3. This information supports the design of pDNA/ligands-grafted cationic liposome complexes for cell-specific gene delivery after intravenous administration.

Animals↗
PubMed2003

Globular adiponectin upregulates nitric oxide production in vascular endothelial cells.

AIMS/HYPOTHESIS: Adiponectin, also called ACRP30, is a novel adipose tissue-specific protein that has been shown to improve insulin sensitivity and to exert anti-atherogenic effects. It is known that knockout mice lacking endothelial NO synthase (eNOS) develop hypertension, insulin resistance, hyperlipidaemia, and show augmented ischaemia-reperfusion damage. Thus, we examined whether globular adiponectin activates eNOS to produce NO. METHODS: To analyze NO production in bovine aortic endothelial cells (BAE), NOx (nitrite and nitrate) was measured in the medium with an automated NO detector/high-performance liquid chromatography system. eNOS activation was assessed by phosphorylation of the enzyme and its activity was evaluated by citrulline synthesis in human umbilical vein endothelial cells (HUVEC). eNOS mRNA and protein expressions in HUVEC were evaluated by Realtime PCR and Western blot analysis. RESULTS: Gobular adiponectin increased NO production in BAE. It also caused eNOS phosphorylation and potentiated eNOS activity in HUVEC. In addition, globular adiponectin up-regulated the eNOS gene to increase protein expression in HUVEC. CONCLUSION/INTERPRETATION: Globular adiponectin increases NO production through two mechanisms, namely, by activation of eNOS enzyme activity and via an increase in eNOS expression. Activation and up-regulation of eNOS could explain some of the observed vasoprotective properties of globular adiponectin, as well as its beneficial effects on the cardiovascular system.

Adiponectin↗
PubMed2003

Recombinant monoclonal thyrotropin-stimulation blocking antibody (TSBAb) established from peripheral lymphocytes of a hypothyroid patient with primary myxedema.

Anti-TSH receptor antibodies (TRAbs) have been known to be involved in Graves' disease and primary hypothyroidism. We previously isolated and reconstituted immunoglobulin (Ig) genes of Epstein-Barr virus-transformed B cell clones producing monoclonal TRAbs obtained from Graves' patients. In the present study, we performed a similar experiment using a B cell clone, 32A-5, derived from a patient with primary hypothyroidism. The variable region genes of Ig heavy (H) and light (L) chains were isolated and sequenced from the 32A-5 clone. A significant number of somatic mutations were found in variable regions of H and L chain gene segments. Each pair of H and L chain cDNAs was ligated into an expression vector for IgG1 production and stably introduced into myeloma cells. The transfectants were injected ip into BALB/c mice to yield ample volume of the antibody for following applications. Interactions of recombinant 32A-5 with Graves' sera with varying thyroid-stimulating antibody (TSAb) activities were studied. The recombinant antibody tended to suppress TSAb activities in 10 of 15 Graves' sera, in which four were significantly inhibited. In summary, this is the first study to analyze human monoclonal TSH-stimulation blocking antibodies (TSBAb) at the molecular level. Use of human recombinant monoclonal TSBAb may be an analytical tool for molecular-basis etiology and an alternative therapeutic path for Graves' disease.

Animals↗
PubMed2003

Occlusal and TMJ loads in subjects with experimentally shortened dental arches.

To determine whether shortened dental arches (SDAs) cause functional overloading of the teeth and the temporomandibular joints, which has been implicated in periodontal diseases and temporomandibular disorders, we investigated the influences of SDA on occlusal and joint loads. Bite force and masticatory muscle electromyograms were recorded in five dentate subjects who clenched maximally on intra-oral appliances, creating symmetrical SDAs experimentally. Muscular forces estimated from the recorded electromyograms were fed into a finite element jaw model for calculating bite forces and joint loads. Comparison between the measured and the calculated bite forces ensured that the joint loads were representative. The bite force on each tooth increased with missing molar occlusions, while joint loads decreased. The bite force per root surface area was always greatest on the most posterior tooth, and these values were most constant. The findings provide no evidence that SDA causes overloading of the joints and the teeth, which suggests that neuromuscular regulatory systems are controlling maximum clenching strength under various occlusal conditions.

Adaptation, Physiological↗
PubMed2003

Diminished penile expression of vascular endothelial growth factor and its receptors at the insulin-resistant stage of a type II diabetic rat model: a possible cause for erectile dysfunction in diabetes.

Erectile dysfunction (ED) is commonly experienced in men with diabetes mellitus. Vascular endothelial growth factor (VEGF) has been extensively documented for its pathogenic significance in different complications of diabetes. We hypothesized that expressions of VEGF, its receptors and its signaling pathway Akt may be drastically altered in diabetic penile tIssues and their alterations may modulate penile expression of the molecules that are believed to play a role in diabetic ED. Otsuka Long-Evans Fatty (OLETF) rats, a type II (non-insulin-dependent) diabetes mellitus, were used at the insulin-resistant stage of type II diabetes (20 weeks of age). We determined protein and mRNA expressions of VEGF, its receptors, Akt, nitric oxide synthase isoforms, and apoptosis-related molecules in the penis using immunohistochemistry, Western blotting, in situ hybridization, and real-time quantitative PCR analyses. The penile sections were also submitted to the Tdt-mediated dUTP nick end labeling assay for apoptosis. OLETF rats showed marked reductions in penile expression of VEGF, its two receptors and Akt. In OLETF rat penises, endothelial and neuronal nitric oxide synthase isoforms were expressed less abundantly. Furthermore, while anti-apoptotic markers, Bcl-2 and phosphorylated Bad, were down-regulated, pro-apoptotic markers, active caspase-3 and Bax, were up-regulated, resulting in the appearance of apoptotic cells in the penile tIssues of OLETF rats. The VEGF signaling system would work less well in diabetic penile tIssues as a result of the reduced expression, leading to diminished endothelial production of nitric oxide and apoptosis-related erectile tIssue damage. We propose that the abnormalities of the VEGF signaling system in the penis may play a role in the pathophysiology of diabetic ED.

Animals↗