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Biomedical subjects

H Yasuda

Publications and source records attributed to H Yasuda.

At least 37 records · Page 2Linked to original sources
PubMed2004

T lymphocyte response against pancreatic beta cell antigens in fulminant Type 1 diabetes.

AIMS/HYPOTHESIS: Fulminant Type 1 diabetes is a novel subtype of Type 1 diabetes that involves the abrupt onset of insulin-deficient hyperglycaemia. This subtype appears to be non-autoimmune because of the absence of diabetes-related autoantibodies in the serum, and of insulitis in pancreatic biopsy specimens. The pathogenesis of the disease is still unknown. In this study, we investigated whether T cell autoimmune responses are involved in fulminant Type 1 diabetes. METHODS: Cellular immune responses to beta cell autoantigens were studied by enzyme-linked immunospot (ELISPOT) assay in 13 fulminant Type 1 diabetic patients and 49 autoantibody-positive autoimmune Type 1 diabetic patients. Results were compared with those of 18 Type 2 diabetic patients, six secondary diabetic patients (diabetes due to chronic pancreatitis) and 35 healthy controls. RESULTS: Nine of 13 (69.2%) GAD-reactive Th1 cells, and three of 12 (25%) insulin-B9-23-reactive Th1 cells were identified in fulminant Type 1 diabetic patients by ELISPOT, as in autoantibody-positive Type 1 diabetic patients. Four fulminant Type 1 diabetic patients possessed the highly diabetes-resistant allele DR2, three of whom had GAD-reactive Th1 cells in the periphery. CONCLUSIONS/INTERPRETATION: Peripheral immune reaction was observed in 69.2% of fulminant Type 1 diabetic patients, indicating that autoreactive T cells might contribute, at least in part, to the development of fulminant Type 1 diabetes.

Adolescent↗
PubMed2004

Nonlinear responses of electronic-excitation-induced phase transformations in GaSb nanoparticles.

We studied electronic-excitation-induced phase transformations in nanoparticles using transmission electron microscopy. GaSb particles excited by 75 keV electrons transform to two phases consisting of an antimony core and a gallium shell or an amorphous phase, or remain in the original crystalline phase, depending on particle size and/or temperature. It is suggested that such nonlinear responses of the phase transformations may arise from synergistic effects of bond instability, localized excitations, enhanced diffusivity, or thermal equilibrium in reactions.

Journal Article↗
PubMed2004

Brain-derived neurotrophic factor increases inhibitory synapses, revealed in solitary neurons cultured from rat visual cortex.

To elucidate chronic actions of brain-derived neurotrophic factor (BDNF) on GABAergic synapses, we examined effects of a long-term application of BDNF for 10-15 days on autapses (synapses) of solitary GABAergic neurons cultured from rat visual cortex. Solitary neuron preparations were used to exclude a possible contamination of BDNF actions on excitatory neurons in dissociated neuron culture or slice preparations. Neurons were confirmed to be GABAergic pharmacologically with bicuculline, a selective antagonist for GABAA receptors and immunocytochemically with antibody against glutamic acid decarboxylase 65, a GABA synthesizing enzyme. To evaluate GABAergic synaptic function, evoked and/or miniature inhibitory postsynaptic currents (IPSCs) were recorded in the whole-cell voltage-clamp mode. The treatment with BDNF at a concentration of 100 ng/ml enhanced the amplitude of evoked IPSCs and the frequency of miniature IPSCs. In contrast, BDNF did not have a detectable effect on the amplitude of miniature IPSCs and the paired pulse ratio of IPSCs evoked by two, successive activations. To evaluate morphological changes, neurons were immunocytochemically stained with antibodies against microtubule-associated protein 2, to visualize somatodendritic region and synapsin I, to visualize presynaptic sites. The quantitative analysis indicated that BDNF increased the area of soma, the numbers of primary dendrites and dendritic branching points, the total length of dendrites and the number of synaptic sites. Such an action of BDNF was seen in both subgroups of GABAergic neurons, parvalbumin-positive and -negative neurons. To visualize functionally active presynaptic sites, neurons were stained with a styryl dye, FM1-43. BDNF increased the number of stained sites that was correlated with the frequency of miniature IPSCs. These results suggest that the chronic treatment with BDNF promotes dendritic and synaptic development of GABAergic neurons in visual cortex.

Analysis of Variance↗
PubMed2004

Human airway submucosal glands augment eosinophil chemotaxis during rhinovirus infection.

BACKGROUND: Asthma exacerbations are frequently associated with rhinovirus (RV) infections. However, the contribution of airway submucosal gland (SMG) to exacerbations of asthma in RV respiratory infection has not been studied. OBJECTIVE: This study was undertaken to examine whether RV-infected human respiratory SMG cells produce pro-inflammatory cytokines and chemokines for eosinophils, and augment eosinophil transmigration across human airway epithelium. METHODS: We infected cultured human tracheal SMG cells with RV14, collected culture media at 1, 3, and 5 days after infection, and measured the chemotactic activity for eosinophils in the culture supernatant using a 48-well microchemotaxis chamber and a (51)Cr-labelled eosinophil transmigration assay. RESULTS: Exposing a confluent human tracheal SMG cell monolayer to RV14 consistently led to infection. Human SMG cells with RV infection secreted soluble factors activating human eosinophil chemotaxis into the culture supernatant in a time-dependent manner, and the culture supernatant significantly augmented the transmigration of (51)Cr-labelled eosinophils through human airway epithelial cell layers from the basal to mucosal side. These effects were completely abolished by a mixture of a monoclonal antibody regulated on activation, normal T cells expressed and secreted (RANTES) and an antibody to granulocyte macrophage-colony stimulating factor (GM-CSF). CONCLUSION: These results suggest that human respiratory SMG cells may augment eosinophil transmigration across the airway epithelium through the secretion of RANTES and GM-CSF after RV infection, and may contribute to exacerbations of asthma.

Adult↗
PubMed2004

Lancefield group C Streptococcus dysgalactiae infection responsible for fish mortalities in Japan.

A Lancefield serological group C Streptococcus sp. was isolated from cultured amberjack, Seriola dumerili Risso, and yellowtail, Seriola quinqueradiata Temminck and Schlegel, immunized with Lactococcus garvieae commercial vaccines in Japan. The isolated bacteria were Gram-positive cocci, auto-aggregating in saline, morphologically long chains in growth medium, catalase negative and alpha-haemolytic on blood agar. An almost complete gene sequence of the 16S rDNA of two isolates was determined and compared with that of bacterial strains in the database. The isolates were identified as Streptococcus dysgalactiae based on the results of the 16S rDNA sequence, the bacteriological properties and the Lancefield serological grouping. Oligonucleotide primers specifically designed for the 16S-23S rDNA intergenic spacer region of S. dysgalactiae amplified a gene from all the fish isolates, as well as the type strains alpha-haemolytic S. dysgalactiae subsp. dysgalactiae ATCC430738 and beta-haemolytic S. dysgalactiae subsp. equisimilis ATCC35666, but not those of S. equi ATCC33398, Lactococcus garvieae ATCC43921 and L. garvieae KG9408. The severe necrotic lesions of the caudal peduncle seen in experimentally infected fish were similar to those seen in naturally infected fish.

Animals↗
PubMed2004

Magnetic resonance spectroscopic determination of a neuronal and axonal marker in white matter predicts reversibility of deficits in secondary normal pressure hydrocephalus.

BACKGROUND: Normal pressure hydrocephalus (NPH) is considered to be a treatable form of dementia, because cerebrospinal fluid (CSF) shunting can lessen symptoms. However, neuroimaging has failed to predict when shunting will be effective. OBJECTIVE: To investigate whether 1H (proton) magnetic resonance (MR) spectroscopy could predict functional outcome in patients after shunting. METHODS: Neurological state including Hasegawa's dementia scale, gait, continence, and the modified Rankin scale were evaluated in 21 patients with secondary NPH who underwent ventriculo-peritoneal shunting. Outcomes were measured postoperatively at one and 12 months and were classified as excellent, fair, or poor. MR spectra were obtained from left hemispheric white matter. RESULTS: Significant preoperative differences in N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) were noted between patients with excellent and poor outcome at one month (p = 0.0014 and 0.0036, respectively). Multiple regression analysis linked higher preoperative NAA/Cr ratio, gait score, and modified Rankin scale to better one month outcome. Predictive value, sensitivity, and specificity for excellent outcome following shunting were 95.2%, 100%, and 87.5%. Multiple regression analysis indicated that NAA/Cho had the best predictive value for one year outcome (p = 0.0032); predictive value, sensitivity, and specificity were 89.5%, 90.0%, and 88.9%. CONCLUSIONS: MR spectroscopy predicted long term post-shunting outcomes in patients with secondary NPH, and it would be a useful assessment tool before lumbar drainage.

Adult↗
PubMed2004

Two cases of subepidermal blistering disease with anti-p200 or 180-kD bullous pemphigoid antigen associated with psoriasis.

We describe two patients with psoriasis vulgaris who subsequently developed a subepidermal blistering disease which disclosed IgG and C3 at the basement membrane zone in direct immunofluorescence. The first case was a 75-year-old Japanese man with herpetiform lesions. Histopathology showed neutrophil infiltration. IgG antibodies bound to the dermal side of the salt-split skin. Immunoblot analysis identified a 200-kD antigen in dermal extracts. The second case was a 70-year-old Japanese man. Histopathology showed eosinophil infiltration. IgG antibodies bound to the epidermal side of salt-split skin. Immunoblot analysis identified a 180-kD bullous pemphigoid (BP) antigen in epidermal extracts. We review the clinical and pathological features of psoriatic patients who presented a subepidermal blistering disease in which antigens were detected by immunoblot analysis; i.e., anti-p200 pemphigoid (14 cases) or BP (12 cases). There were few distinct clinical differences between two diseases. However, neutrophils were predominant in anti-p200 pemphigoid, while eosinophils were predominant in BP. After blister formation, ciclosporin was used effectively in addition to systemic steroids in the treatment of anti-p200 pemphigoid. On the other hand, ciclosporin was not used in the treatment of BP with psoriasis.

Aged↗
PubMed2003

Extramammary Paget's disease with superimposed herpes simplex virus infection: immunohistochemical comparison with cases of the two respective diseases.

We describe an extremely rare case of genital Paget's disease with superimposed herpes simplex virus (HSV) infection. We also describe immunohistochemical comparison of this lesion with 19 cases of genital Paget's disease and 12 cases of skin lesions caused by HSV or varicella-zoster virus. The Paget cells expressed simple epithelial keratins (CK7 and CK19) and carcinoembryonic antigen (CEA), but did not express stratified epithelial keratins (CK1, CK2e, CK10, CK5/8, CK14). Conversely, the virus-infected keratinocytes were positive for stratified epithelial keratins but negative for simple epithelial keratins and CEA. In the present case, simple epithelial keratins, stratified epithelial keratins, CEA and HSV were heterogeneously expressed in the ballooning and multinucleated giant cells. These results suggest that these cells were derived from keratinocytes and Paget cells and that the production of many multinucleated giant cells resulted from the virus-mediated cell fusion between Paget cells and neighbouring keratinocytes.

Aged↗
PubMed2003

Critical roles of CD30/CD30L interactions in murine autoimmune diabetes.

CD30/CD30L is a member of tumour necrosis factor (TNF) receptor/TNF superfamily and has been implicated in immune-regulation. A genetic study has also suggested a possible implication of CD30 in spontaneous autoimmune diabetes in NOD mice. In this study, we investigated the involvement of CD30/CD30L in the development of diabetes in NOD mice. Flow cytometric analysis showed that CD30 and CD30L were highly expressed on CD4+ or CD8+ T cells in the spleen and pancreatic lymph node of younger NOD mice. In addition, islet-specific CD4+ or CD8+ T cell lines expressed CD30 and CD30L. Administration of a neutralizing anti-CD30L monoclonal antibody (mAb) from 2 to 10 week of age completely suppressed the development of spontaneous diabetes in NOD mice. In addition, the treatment with anti-CD30L mAb also inhibited the development of diabetes induced by adoptive transfer of spleen cells from diabetic NOD mice or islet-specific CD4+ or CD8+ T cell lines into NOD-SCID mice. Furthermore, anti-CD30L mAb inhibited T cell proliferation in response to islet antigens. These results suggested that CD30/CD30L interaction plays important roles in both induction and effector phases of autoimmune diabetes in NOD mice.

Adoptive Transfer↗
PubMed2003

MR angiography for the evaluation of non-systemic vasculitic neuropathy.

Peripheral neuropathy due to vasculitis without any complications of vasculitis in other organs was first reported in 1987. This condition was termed non-systemic vasculitic neuropathy (NSVN). Although vasculitis is believed to develop in small arteries and arterioles in this disease, the level of vascular involvement has not been fully established. We present a case of NSVN followed up by MR angiography, which was thought to be useful to assess the level as well as the state of vascular lesions in this condition.

Adult↗
PubMed2003

Activin A is an autocrine activator of rat pancreatic stellate cells: potential therapeutic role of follistatin for pancreatic fibrosis.

BACKGROUND AND AIM: The present study was conducted to examine the effect of activin A on activation of rat pancreatic stellate cells (PSCs). METHODS: PSCs were prepared from rat pancreas using collagenase digestion and centrifugation with Nycodenz gradient. Activation of PSCs was examined by determining smooth muscle actin expression with western blotting. The presence of activin A receptors in PSCs was investigated by reverse transcription-polymerase chain reaction (RT-PCR), western blotting, and immunocytochemistry. Expression of activin A and transforming growth factor beta (TGF-beta) mRNA was examined by RT-PCR. Activin A and TGF-beta peptide concentrations were examined with ELISA. Existence of activin A peptide in PSCs was investigated by immunocytochemistry. Collagen secretion was determined by Sirius red dye binding. RESULTS: Activin A receptors I and IIa were present in PSCs. PSCs expressed activin A mRNA and secreted activin A. Activin A enhanced PSC activation and collagen secretion in a dose dependent manner. TGF-beta and activin A increased each other's secretion and mRNA expression of PSCs. Follistatin decreased TGF-beta mRNA expression and TGF-beta secretion of PSCs, and inhibited both PSC activation and collagen secretion. CONCLUSION: Activin A is an autocrine activator of PSCs. Follistatin can inhibit PSC activation and collagen secretion by blocking autocrined activin A and decreasing TGF-beta expression and secretion of PSCs.

Actins↗
PubMed2003

[Analysis of continuous hemodiafiltration after open heart surgery].

The development of renal failure after open heart surgery is associated with a high mortality. Thirteen patients were treated with continuous hemodiafiltration (CHDF) for renal failure following open heart surgery since April 1999 to December 2001. The indication of CHDF was blood purification in 8 patients and water balance control in 5 patients. Two patients with hemodialysis (HD) before operation returned to usual HD early after operation, and discharged. One patient died of severe heart failure, and another patient died of sepsis and multi organ failure. In these 2 patients, CHDF could not withdrawn. Seven patients weaned from CHDF 1 to 19 days after operation. Five of 7 patients discharged, but 2 patients died of cerebral infarction 4 month after operation. The remaining 2 patients could not wean from CHDF, and were introduced HD. Only 1 of 13 patients had bleeding tendency (cardiac tamponade). CHDF did not influence the hemodynamic state and was very effective for the treatment of renal failure in many patients.

Aged↗
PubMed2003

[Routine application of trans-sternal off-pump coronary artery bypass grafting using innovative technique].

OBJECTIVE: With specific apparatus and surgical techniques, we have extended the use of off-pump coronary artery bypass grafting (CABG) [OPCAB] through sternotomy approach to all of the patients with multiple coronary vessel lesions necessitating CABG. The objective of this study is to assess the safety and efficacy of our technique. METHODS: All of the consecutive 100 patients with multiple coronary vessel lesions necessitating CABG underwent trans-sternal OPCAB using our innovative technique between September 2000 and December 2002. Our new technique included left pericardial traction with sternal spreader, right pericardial compression with pericardial retractor and routine use of our original coronary shunt tube. RESULTS: The total number of distal anastomoses was 322 and the individual grafts were to left anterior descending coronary artery branch (LAD) 127, circumflex (CX) 101 and right coronary artery (RCA) 94. The mean number of the grafts was 3.22 +/- 0.97. The conduits included left internal thoracic artery (LITA) 103, right internal thoracic artery (RITA) 29, radial artery (RA) 82, gastro-epiploic artery (GEA) 43 and saphena magna vein graft (SVG) 65. Predischarge graft angiogram showed over all patency of 99.1% (arterial graft 100% and vein graft 95.4%). Postoperative course was uneventful in all cases with no other organ failures. There was no operative or hospital death. CONCLUSIONS: OPCAB of our technique is effective and safe. The early clinical outcome and excellent patency rates suggests its more widespread use in CABG cases.

Adult↗
PubMed2003

[The analysis of renal function in off-pump coronary artery bypass grafting].

OPCAB (off-pump coronary artery bypass grafting) is useful for preventing post-operative neurologic complications. On the other hand, the effect of OPCAB on post-operative renal function is still unclear. We analyzed the post-operative renal function in 39 patients. Thirty-two patients had normal pre-operative renal function (CRE < or = 1.4 mg/dl). Thirty-one patients were doing well in terms of post-operative renal function. Only 1 patient needed hemodialysis (HD) because of systemic infection in early post-operative period. Another 7 patients had pre-operative renal dysfunction (CRE > or = 1.5 mg/dl). Three cases with high-grade pre-operative renal dysfunction (CRE > 3.0 mg/dl and CCR < 20 ml/min) needed temporary HD or continuous hemo-diafiltration (CHDF) in early post-operative period, and then they needed maintenance HD for the treatment of chronic renal failure within 3 weeks after OPCAB. Three of 4 cases with low-grade pre-operative renal dysfunction (CRE: 1.9-2.7 mg/dl and CCR: 22-42 ml/min) needed temporary HD or CHDF in early post-operative period. These 3 patients were relieved of the early post-operative renal failure, but required maintenance HD in the late periods. In summary, OPCAB could not prevent the development of acute renal failure in the patients with pre-operative renal dysfunction.

Aged↗
PubMed2002

Probability of cell hits in selected organs and tissues by high-LET particles at the ISS orbit.

The fluence of high-LET particles (HLP) with LET infinity H2O greater than 15 keV micrometers-1 in selected organs and tissues were measured with plastic nuclear track detectors using a life-size human phantom on the 9th Shuttle-Mir Mission (STS-91). The planar-track fluence of HLP during the 9.8-day mission ranged from 1.9 x 10(3) n cm-2 (bladder) to 5.1 x 10(3) n cm-2 (brain) by a factor of 2.7. Based on these data, a probability of HLP hits to a matured cell of each organ or tissue was roughly estimated for a 90-day ISS mission. In the calculation, all cells were assumed to be spheres with a geometric cross-sectional area of 500 micrometers2 and the cell-hit frequency from isotropic space radiation can be described by the Poisson-distribution function. As results, the probability of one or more than 1 hit to a single cell by HLP for 90 days ranged from 17% to 38%; that of two or more than 2 hits was estimated to be 1.3-8.2%.

Brain↗
PubMed2002

Solid-state integrating detectors as an indicator of biological doses from HZE particles.

For interpretation of results obtained in future biological experiments in the International Space Station (ISS), biologically equivalent doses have to be determined using small-scale detectors without disturbing the surrounding radiation field. The detectors should be lightweight, stable, safe, and simple in handling. Solid-state integrating detectors (SSID) can satisfy these requirements. This paper demonstrates that combination of SSID such as thermoluminescence dosimeters and radiophotoluminescence glasses can be practically used for the evaluation of biologically equivalent doses. Statistical errors (type-A uncertainty) of this method will be satisfactorily small relative to those generally observed in biological responses. Permissible levels of systematic errors (type-B uncertainty) depend on dosimetry purposes (most-probable or conventional) and variability of biological responses.

Animals↗
PubMed2002

Effects of gamma-ray and high energy carbon ion irradiation on swimming velocity of Euglena gracilis.

The effects of gamma-ray and high energy carbon ion irradiation on the swimming velocity of the photosynthetic flagellate Euglena gracilis strain Z were studied, focusing on a dose-effect relationship. Cells were exposed to 60Co gamma-rays at 6 doses of 10, 15, 20, 40, 100 and 200 Gy for water, and also to 290 MeV/amu carbon ions from the Heavy Ion Medical Accelerator in Chiba at 7 doses (5, 10, 15, 20, 50, 100 and 200 Gy for water). The swimming velocity was measured by a biomonitoring system, called ECOTOX. The swimming velocities of Euglena gracilis cells were significantly decreased by >40 Gy gamma-rays and >5 Gy carbon ions, respectively. The 50% effective doses for inhibition, 34 +/- 4 Gy (gamma-rays) and 13 +/- 1 Gy (290 MeV/amu carbon ions), were estimated from the best fit to data of the logistic model. The relative biological effectiveness (2.6 +/- 0.4) was calculated by the ratio of 50% effective doses. The inhibition of the swimming velocity of the cells irradiated with gamma-rays was still present after 3 days, while recovery of the swimming velocity was shown in the cells exposed to 290 MeV/amu carbon ions. It is suggested that ionizing radiation inhibits ATP production and/or increases frictional drag on beating of the flagellum, thus decreasing swimming velocity.

Adenosine Triphosphate↗