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Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 55 records · Page 3Linked to original sources
PubMed2004

Effects of ageing and smoking on SP-A and SP-D levels in bronchoalveolar lavage fluid.

Surfactant protein (SP)-A and SP-D are collagen-like glycoproteins that are synthesised in the distal pulmonary epithelium. This study examined the effects of ageing and long-term smoking on SP-A and SP-D in the lungs. The possible links to the development of pulmonary emphysema were also investigated. Sequential lavage was performed in young and middle-aged or elderly nonsmokers and asymptomatic current smokers with various smoking histories. Middle-aged or elderly smokers were further categorised according to the presence of emphysema by high-resolution computed tomography. Levels of SP-A and SP-D in bronchial lavage (BL) fluid and in bronchoalveolar lavage (BAL) fluid were quantified by ELISA. Significant decreases in SP-A were seen with age in nonsmokers in BL fluid, but not in BAL fluid. Middle-aged or elderly smokers with emphysema had lower levels of SP-A in both BL and BAL fluids when compared with young subjects, and in BL fluid when compared with middle-aged or elderly smokers without emphysema. SP-D did not change with age alone, however, it was decreased in middle-aged or elderly smokers when compared with similarly aged nonsmokers. In conclusion, surfactant protein-A may decrease with age alone or due to the cumulative effects of long-term smoking and development of emphysema, while surfactant protein-D decreases due to long-term smoking.

Adolescent↗
PubMed2004

Endobronchial ultrasonography with guide-sheath for peripheral pulmonary lesions.

The usefulness of endobronchial ultrasonography (EBUS) with guide-sheath (GS) as a guide for transbronchial biopsy (TBB) for diagnosing peripheral pulmonary lesions (PPL)s and for improving diagnostic accuracy was evaluated in this study. EBUS-GS-guided TBB was performed in 24 patients with 24 PPLs of < or =30 mm in diameter (average diameter=18.4 mm). A 20-MHz radial-type ultrasound probe, covered with GS was inserted via a working bronchoscope channel and advanced to the PPL in order to produce an EBUS image. The probe with the GS was confirmed to reach the lesion by EBUS imaging and X-ray fluoroscopy. When the lesion was not identified on the EBUS image, the probe was removed and a curette was used to lead the GS to the lesion. After localising the lesion, the probe was removed, and TBB and bronchial brushing were performed via the GS. Nineteen peripheral lesions (79.2%) were visualised by EBUS. All patients whose PPLs were visible on EBUS images subsequently underwent an EBUS-GS-guided diagnostic procedure. A total of 14 lesions (58.3%) were diagnosed. Even when restricted to PPLs <20 mm in diameter, the diagnostic sensitivity was 53%. In conclusion, endobronchial ultrasonography with guide sheath-guided transbronchial biopsy was feasible and effective for diagnosing peripheral pulmonary lesions.

Adult↗
PubMed2004

[Multi-vessel dissection; report of a case].

We report an extremely rare case of multi-vessel dissection including left carotid artery, ascending aorta and thoracoabdominal aorta independently. A 65-year-old man suffered from cerebral infarction due to left carotid artery dissection. Five days later, he complained of severe back pain and was diagnosed as acute DeBakey type IIIb aortic dissection. He had been treated medically. One month later, computed tomography (CT) scan demonstrated DeBakey type II as well as type IIIb aortic dissections. The ascending aorta was replaced on August 8, 2001. Then replacement of the descending thoracic aorta with reconstruction of the eighth and tenth intercostal arteries was performed on September 26, 2001. The left carotid artery dissection has been treated medically.

Aged↗
PubMed2004

[Long survival with chronic ventricular fibrillation under support of uni-left-ventricular assist system].

Few minutes of suspended malignant ventricular arrhythmia may be permitted for the patient with left ventricular assist system (LVAS). However, longer and continuous ventricular arrhythmia, especially ventricular fibrillation (Vf), may induce the low output of LVAS, which leads circulatory collapse immediately. Our presenting case is a female dilated cardiomyopathy patient who has been supported with LVAS. Four months after the LVAS installation, her electrocardiogram has changed to Vf without any symptoms. Her ventricular function has never recovered, even ventricular tachycardia. She has been a candidate of heart transplantation for more than 19 months with this rare hemodynamic condition (LVAS+Vf), like the Fontan circulation. Her performance status is limited due to deceasing of the LVAS flow, which caused by the change of her position: 2.5-2.9 l/min (lie down) to 2.0 l/min (rise). Her peak VO2/W is 6.9 ml/min/kg measured by the cardio-pulmonary exercise test. However, she has developed her general status by doing rehabilitation program and is able to walk for more than 100-150 meters.

Adult↗
PubMed2004

Quantitative analysis of the effects of hyaluronan and aggrecan concentration and hyaluronan size on the elasticity of hyaluronan-aggrecan solutions.

We determined elasticity (G') and viscosity (G'') of various aggrecan-hyaluronan solutions using a controlled-stress rheometer with high (10 Hz) to low (0.1 Hz) frequencies. Aggrecan solution (50 mg/ml) alone showed little elasticity at any frequency, but the addition of 3300 kDa hyaluronan at 0.001-0.1 mg/ml markedly increased the elasticity, but not the viscosity, at all frequencies. Increasing hyaluronan concentration at >0.1 mg/ml did not further increase the elasticity of the aggrecan solution, and the elasticity of the aggrecan-hyaluronan complex solution reached a plateau at a 500:1 (w/w) ratio. In studies with increasing concentrations of aggrecan and a constant concentration (0.5 mg/ml) of 3300 kDa hyaluronan, aggrecan induced elasticity only at >20 mg/ml, indicating the presence of a critical concentration for elasticity. In the presence of 50 mg/ml aggrecan, 1000 kDa hyaluronan had far less effect on the elasticity of the aggrecan solution than did 3300 kDa hyaluronan. These findings suggest that only approximately 50% reduction in aggrecan concentration (<20 mg/ml), or reduced hyaluronan size (<1000 kDa)--compared with their physiological levels in young cartilage--can abolish the elastic network of the aggrecan-hyaluronan complex.

Aggrecans↗
PubMed2003

Modulation of the onset age in primary dystonia by APOE genotype.

APOE polymorphisms were studied in 200 unrelated patients with primary dystonia as well as 300 age-matched control subjects. Although no difference was found in APOE genotype between the patients with dystonia and the controls, APOE-epsilon4 carriers developed the disease on average approximately 10 years earlier than APOE-epsilon4 noncarriers (p = 0.0012). This suggests that APOE-epsilon4 genotype affects the clinical presentation of primary dystonia.

Adolescent↗
PubMed2003

Effects of extracellular Ca2+ on phagocytosis and intracellular Ca2+ concentrations in polymorphonuclear leukocytes of postpartum dairy cows.

The aim of this study was to determine the effects of extracellular Ca(2+) concentration ([Ca(2+)](e)) on phagocytosis and intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine polymorphonuclear leukocytes (PMNs). The experiments were performed by using blood samples from parturient paretic and clinically normal parturient cows and manipulating the [Ca(2+)](e) in vitro. Phagocytosis by PMNs (with and without stimulation with phorbol myristate acetate and inhibition with cytochalasin B) and resting [Ca(2+)](i) were significantly lower in parturient paretic cows. Repletion of Ca(2+) in the extracellular media for the samples from these animals increased phagocytosis and resting [Ca(2+)](i). In the blood of clinically normal parturient cows, decreasing the [Ca(2+)](e) decreased phagocytosis and resting [Ca(2+)](i) in PMNs, but increasing the [Ca(2+)](e) did not affect phagocytosis. These results suggest that the hypocalcemic condition of parturient paretic cows in vivo causes decreased phagocytosis and resting [Ca(2+)](i) in PMNs, which may partly contribute to greater susceptibility to infection.

Adjuvants, Immunologic↗
PubMed2003

Expression of interleukin 6 in synovial tissues in patients with internal derangement of the temporomandibular joint.

Using an immunohistochemical technique, we examined synovial tissue from 46 temporomandibular joints (TMJ) with internal derangement in 44 patients. As controls, we examined synovial tissue specimens from 7 joints with habitual dislocation without pain. In synovial tissues from 21 of the 46 joints with internal derangement, interleukin 6 (IL-6) was expressed in the synovial lining cells and in the mononuclear cells infiltrating the periphery of the blood vessels. The density of IL-6-stained cells in specimens with internal derangement correlated significantly with the grade of joint effusion shown by magnetic resonance imaging (P=0.01, r=0.32).

Adolescent↗
PubMed2003

Relation between the expression of vascular endothelial growth factor in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging in patients with internal derangement of the temporomandibular joint.

The aim of this study is to elucidate the relation between the expression of vascular endothelial growth factor (VEGF) in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging (MRI) in patients with internal derangement of the temporomandibular joint (TMJ). Using an immunohistochemical technique, we examined specimens of synovial tissues from 41 joints in 40 patients with internal derangement. Specimens from 36 of the 41 joints stained for VEGF. There was a significant correlation between the percentage of the VEGF-stained cells and the grade of joint effusion seen on MRI (P=0.0002, r=0.62). The correlation between the two was also significant on multiple logistic regression analysis (P=0.003, odds ratio=1.75). These results suggest that VEGF may have an important role in the genesis of joint effusion.

Adolescent↗
PubMed2003

The activity-regulated cytoskeleton-associated (Arc) gene is a new light-inducible early gene in the mouse suprachiasmatic nucleus.

The mammalian circadian system is entrained to the environmental light/dark cycle by shifting the phase of the master clock in the suprachiasmatic nucleus. Accompanying the light-induced phase-shift, a variety of immediate-early genes appears in suprachiasmatic nucleus clock cells, and here, we report the expression of a new immediate-early gene Arc (activity-regulated cytoskeleton-associated gene) in mice. Arc messenger RNAs were strongly induced at 30-120 min after the light exposure at subjective night (CT12-CT20) in neurons of the retinorecipient area of the suprachiasmatic nucleus, although their spontaneous expression was absent in usual light-dark cycles and in constant dark conditions. At protein level, ARC appeared not only in the nucleus but also in the perikarya and their processes of the suprachiasmatic nucleus neurons. These findings indicate that Arc is an activity-regulated cytoskeletal gene possibly involved in the light-induced phase-shift of the circadian rhythm.

Animals↗
PubMed2003

In vitro cariogenic potential of Candida albicans.

The adherence and dissociation of Candida albicans, C. tropicalis, Streptococcus mutans and S. sanguis to six substrates including hydroxylapatite (HAP) which exhibit various hydrophobicity, was examined by the use of a bioluminescent adenosine triphosphate (ATP) assay. Dissolution of HAP by C. albicans or S. mutans was determined spectrophotometrically by the use of o-cresolphthalein complexone. In the adherence of C. tropicalis, S. mutans and S. sanguis, the amount of adherent cells correlated with the hydrophobicity of the substrates. In contrast, the adherence of C. albicans to HAP was extraordinary high, although the adherence of the fungi also correlated with the hydrophobicity of the substrates, except for HAP. The yeasts attached to HAP was effectively removed by high concentration of either phosphate or calcium ions. The amount of calcium-release from HAP caused by C. albicans and S. mutans was 113 microg ml(-1) (final pH = 3.45), and 5.4 microg ml(-1) (final pH 4.81), respectively and the maximum growth of C. albicans and S. mutans was 10(7) cfu ml(-1) and 7.4 x 10(12) cfu ml(-1), respectively. The results, taken together, suggest that C. albicans adhere to HAP specifically through electrostatic interaction, and that, in a much smaller number (1.0/7.4 x 10(5)), C. albicans possesses the ability to dissolve HAP to a greater extent (approximately 20-fold) when compared with S. mutans.

Bacterial Adhesion↗
PubMed2003

A novel technique to evaluate the adhesion of Candida species to gingival epithelial cells.

We developed an in vitro ATP assay technique to extract cellular and fungal ATP separately, which allowed to evaluate quantitatively the adhesion of the yeasts to monolayers of human gingival epithelial cells. Thirteen isolates of Candida spp. representing three species (i.e. Candida albicans, C. tropicalis and C. glabrata) were used in the present study. When the adherent capacity of the Candida species was compared, C. albicans exhibited highest capacity of adherence to gingival epithelial cells, followed by C. tropicalis, and C. glabrata was the lowest [analysis of variance (ANOVA), P < 0.01]. The germ tubes of C. albicans exhibited significantly higher adherence capacity than their blastoconidia cells (ANOVA, P < 0.01), which was not observed with a C. albicans isolate, defect of germ tube formation. Our results suggested that the adherence of C. albicans is promoted by germ tube formation and may play an important role in the pathogenesis of the fungus.

Adenosine Triphosphate↗
PubMed2003

Age-related accumulation of Ig V(H) gene somatic mutations in peripheral B cells from aged humans.

To investigate age-related alterations in human humoral immunity, we analysed Ig heavy chain variable region genes expressed by peripheral B cells from young and aged individuals. Three hundred and twenty-seven cDNA sequences, 163 micro and 164 gamma transcripts with VH5 family genes, were analysed for somatic hypermutation and VHDJH recombinational features. Unmutated and mutated micro transcripts were interpreted as being from naive and memory IgM B cells, respectively. In young and aged individuals, the percentages of naive IgM among total micro transcripts were 39% and 42%, respectively. D and JH segment usage in naive IgM from aged individuals was similar to that from young individuals. The mutational frequencies of memory IgM were similar in young and aged individuals. gamma transcripts, which are regarded as being from memory IgG B cells, showed a significantly higher mutational frequency (7.6%) in aged than in young individuals (5.8%) (P < 0.01). These findings suggest that VHDJH recombinational diversity was preserved, but that the accumulation of somatic mutations in the IgG VH region was increased in aged humans. The accumulation of somatic mutations in IgG B cells during ageing may imply that an age-related alteration exists in the selection and/or maintenance of peripheral memory B cells.

Adult↗
PubMed2003

Possible mechanisms underlying development of transfusion-related acute lung injury: roles of anti-major histocompatibility complex class II DR antibody.

Anti-major histocompatibility complex (anti-MHC) antibodies (Abs) and antipolymorphonuclear neutrophil (anti-PMN) Abs are generally considered as the main causes of the development of transfusion-related acute lung injury (TRALI), which is one of the most severe and sometimes lethal side effects of transfusion. These Abs are postulated to activate recipient's leucocytes, resulting in the release of soluble factors such as reactive oxygen species and detrimental cytokines and chemokines. The harmful effects on the lung tissues and resident leucocytes of these malignant factors are suspected to be profoundly involved in TRALI reactions. Several reports have indicated the principle effect of biologically active lipids on the pathogenesis of TRALI. However, the precise mechanisms of TRALI development remain unclear. To resolve this issue, we have been investigating cytokines that induce continuous inflammation of the lungs, specifically focusing on the cytokines derived from activated PMNs. We observed that the granulocyte-macrophage colony-stimulating factor (GM-CSF) markedly enhances the expression of MHC class II DR in PMNs. Moreover, MHC class II DR-expressing PMNs were also proved to express a high-affinity receptor for immunoglobulin E (IgE) (FcepsilonRI) and to produce tumour necrosis factor-alpha, interferon-gamma and interleukin-18 following a challenge with an anti-MHC class II DR monoclonal Ab (MoAb) or anti-DR antiserum. It is strongly suggested that amongst various inflammatory mediators, at least these three cytokines may contribute to the duration of inflammatory reactions in the lungs. Furthermore, FcepsilonRI expression, in GM-CSF-treated PMNs, suggests the involvement of PMNs in IgE-mediated immune reactions.

Cytokines↗
PubMed2003

Osteoclastogenesis inhibitory factor/osteoprotegerin in synovial fluid from patients with temporomandibular disorders.

The goal of this study was to measure the activities of osteoclastogenesis inhibitory factor/osteoprotegerin (OCIF/OPG), interleukin-1beta (IL-1beta), and tumour necrosis factor-alpha (TNF-alpha) in synovial fluid from 24 patients with internal derangement and 26 with osteoarthritis of the temporomandibular joint (TMJ). Five asymptomatic healthy volunteers were studied as control. Concentrations of OCIF/OPG, IL-1beta, and TNF-alpha were determined by enzyme-linked immunosorbent assay. The mean OCIF/OPG concentration in the patients with osteoarthritis (71 pg/ml) was significantly lower than those in the patients with internal derangement (160 pg/ml, P< 0.05) and the healthy volunteers (196 pg/ml, P< 0.01). In contrast, the IL-1beta and TNF-alpha concentrations were similar in all three groups. These results suggest that OCIF/OPG is associated with the pathogenesis of osteoarthritis of the TMJ. Perhaps, decreased OCIF/OPG concentrations promote osteoclastic activity and induce osteoarthritis of the TMJ.

Adolescent↗
PubMed2003

Genetic susceptibility to thymic lymphomas and K-ras gene mutation in mice after exposure to X-rays and N-ethyl-N-nitrosourea.

PURPOSE: Ras activation is one of the major mechanisms for the development of murine thymic lymphomas by radiation and chemical carcinogens. To gain insight into the relationship between genetic susceptibility and ras gene mutation, the frequency and spectrum of ras gene mutation was examined in thymic lymphomas from susceptible and resistant mice. MATERIALS AND METHODS: K- and N-ras mutations in thymic lymphomas that arose in X-ray-irradiated and N-ethyl-N-nitrosourea (ENU)-treated mice of susceptible C57BL/6, rather resistant C3H and their hybrid B6C3F1 were analysed by polymerase chain reaction-single-strand conformation polymorphism and subsequent DNA sequencing. RESULTS: C57BL/6 exhibited a higher incidence of thymic lymphomas after exposure to X-rays and ENU than C3H, with B6C3F1 being intermediate. K-ras gene mutations occurred frequently in the pathogenesis of ENU-induced thymic lymphomas in susceptible C57BL/6 as opposed to resistant C3H. The ras mutations were more frequent in ENU-induced thymic lymphomas than X-ray-induced thymic lymphomas, and with the latter, there was no clear evidence for strain differences, suggesting that the genetic susceptibility to X-rays was independent of ras activation. The mutations of K-ras in thymic lymphomas from C57BL/6 were predominantly GGT to GAT in codon 12, whereas this mutation type was never found in those from C3H. No strain difference was observed in the nucleotide sequence or expression levels of O(6)-alkylguanine alkyltransferase, indicating that this enzyme did not account for the genetic susceptibility to ras activation. CONCLUSIONS: The results indicate that there is a clear strain and carcinogen dependency of K-ras mutation and that the frequency of ras mutation might determine the genetic susceptibility to ENU-induced lymphomagenesis, whereas pathways independent of ras activation might determine the susceptibility to X-ray-induced lymphomagenesis.

Alkylating Agents↗