Biomedical subjects

K Tomita

Publications and source records attributed to K Tomita.

At least 19 recordsLinked to original sources

PubMed2006

Inhibition of prostasin-induced ENaC activities by PN-1 and regulation of PN-1 expression by TGF-beta1 and aldosterone.

Prostasin has been shown to regulate sodium handling in the kidney. Recently, a serine protease inhibitor, protease nexin-1 (PN-1), was identified as an endogenous inhibitor for prostasin. Therefore, we hypothesized that PN-1 may regulate sodium reabsorption by reducing prostasin activity, and that expression of PN-1 was regulated by transforming growth factor-beta1 (TGF-beta1) or aldosterone, like prostasin. cRNAs for epithelial sodium channel (ENaC), prostasin, and PN-1 were expressed in Xenopus oocytes, and the amiloride-sensitive sodium currents (I(Na)) were measured. The effect of TGF-beta1 and aldosterone on the mRNA and protein abundance of PN-1 and ENaC was detected by real-time polymerase chain reaction and immunoblotting in M-1 cells. Expression of PN-1 substantially decreased prostasin-induced I(Na) by approximately 68% in oocytes. Treatment of M-1 cells with 20 ng/ml TGF-beta1 significantly increased protein expression of PN-1 by 3.8+/-0.5-fold, whereas administration of 10(-6) M aldosterone markedly decreased protein expression of PN-1 to 53.7+/-6.7%. Basolateral, but not apical, application of TGF-beta1 significantly reduced I(eq). To elucidate the involvement of PN-1 in basal ENaC activity, we silenced the expression of PN-1 by using short-interfering RNA. This increased I(eq) by 1.6+/-0.1-fold. Our study indicates that PN-1 could have a natriuretic role by inhibiting prostasin activity and suggests the possibility that aldosterone and TGF-beta reciprocally regulate the expression of PN-1 in renal epithelial cells contributing to salt retention or natriuresis, respectively by an additional mechanism. PN-1 could represent a new factor that contributes to regulation of ENaC activity in the kidney.

Aldosterone↗

PubMed2006

Powdery mildew (Podosphaera xanthii) resistance in melon is categorized into two types based on inhibition of the infection processes.

Physiological races of powdery mildew (Podosphaera xanthii) cause different symptoms in eight melon lines. Infection by races 1, 2, and 5 was examined in different melon lines. After a compatible reaction, conidia germination, haustorium initiation from the germ tube, germ tube branching, and sporulation occurred within 12, 24, 48, and 120 h, respectively, and the conidia matured within 240 h. In contrast, type i and ii inhibition were identified through incompatible reactions. The germ tube and haustorium were initiated from conidia, but no germ tube branching occurred in the lines with type i resistance within 48-240 h. In type ii resistance, germ tube branching was observed within 120 h, but no sporulation was observed within 240 h. The number of fluorescing epidermal cells was higher within 24 h in type i, and within 48-120 h in type ii resistance lines than in susceptible lines. Callose accumulation around the haustorium was detected in type ii resistance lines within 48-120 h. This suggests that the rapid hypersensitive response (HR) within 24 h has an important role in the type i response, while HR and callose accumulation in the type ii response occur slowly between 48 and 120 h. Of the resistant lines, PMR 45 and WMR 29 showed a type i incompatible response; the PI 414723 response was entirely type ii; and PMR 5, PI 124112, and MR-1 showed different responses depending on the race. Therefore, the two types of incompatible responses were intermixed in the same germplasm.

Ascomycota↗

PubMed2006

Radiation myelopathy after radioactive iodine therapy for spine metastasis.

A case of radiation myelopathy after radioactive iodine therapy is reported. This is the first report to describe radiation myelopathy after I-131 therapy. A 62-year-old female with spinal metastasis of T10 received I-131 therapy. She presented with radiation myelopathy 34 months after the irradiation. We need to recognize the possibility of this serious complication even in the case of I-131 therapy. There is a risk of radiation myelopathy even after I-131 therapy, especially in cases with spinal cord compression such as this.

Female↗

PubMed2005

Tumour necrosis factor alpha signalling through activation of Kupffer cells plays an essential role in liver fibrosis of non-alcoholic steatohepatitis in mice.

BACKGROUND: While tumour necrosis factor alpha (TNF-alpha) appears to be associated with the development of non-alcoholic steatohepatitis (NASH), its precise role in the pathogenesis of NASH is not well understood. METHODS: Male mice deficient in both TNF receptors 1 (TNFR1) and 2 (TNFR2) (TNFRDKO mice) and wild-type mice were fed a methionine and choline deficient (MCD) diet or a control diet for eight weeks, maintaining isoenergetic intake. RESULTS: MCD dietary feeding of TNFRDKO mice for eight weeks resulted in attenuated liver steatosis and fibrosis compared with control wild-type mice. In the liver, the number of activated hepatic Kupffer cells recruited was significantly decreased in TNFRDKO mice after MCD dietary feeding. In addition, hepatic induction of TNF-alpha, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 was significantly suppressed in TNFRDKO mice. While in control animals MCD dietary feeding dramatically increased mRNA expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) in both whole liver and hepatic stellate cells, concomitant with enhanced activation of hepatic stellate cells, both factors were significantly lower in TNFRDKO mice. In primary cultures, TNF-alpha administration enhanced TIMP-1 mRNA expression in activated hepatic stellate cells and suppressed apoptotic induction in activated hepatic stellate cells. Inhibition of TNF induced TIMP-1 upregulation by TIMP-1 specific siRNA reversed the apoptotic suppression seen in hepatic stellate cells. CONCLUSIONS: Enhancement of the TNF-alpha/TNFR mediated signalling pathway via activation of Kupffer cells in an autocrine or paracrine manner may be critically involved in the pathogenesis of liver fibrosis in this NASH animal model.

Animals↗

PubMed2005

Onset of steroid-induced osteonecrosis in rabbits and its relationship to hyperlipaemia and increased free fatty acids.

OBJECTIVES: To clarify the initial onset time of osteonecrosis after the start of steroid treatment and its relation to the onset of abnormal lipid metabolism. METHODS: Animal models were prepared by administering methylprednisolone to rabbits using five different steroid regimens. RESULTS: A single, acute ischaemic event suggested by the frequency, size or number of necrotic foci within the proximal femur was not different among the groups. Histological evidence of osteonecrosis first occurred 1-2 weeks after initial steroid administration. At the same time there were significantly abnormal elevations in serum lipids, which persisted for between 1 and 2 weeks after the initial corticoid treatment. Triglycerides, total cholesterol and free fatty acids were markedly elevated in all groups; these lipid abnormalities were significantly present in the rabbits with osteonecrosis but not in the rabbits without osteonecrosis. CONCLUSIONS: This study shows that (i) osteonecrosis appears in rabbits shortly after corticoids are first administered, and (ii) osteonecrosis in rabbits is chronologically associated with the onset of hyperlipaemia and increased free fatty acids. This supports the occurrence of intraosseous fat embolism as a cause of osteonecrosis.

Animals↗

PubMed2005

Reconstruction using an autograft containing tumour treated by liquid nitrogen.

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

Adolescent↗

PubMed2005

Identification of Fabry's disease by the screening of alpha-galactosidase A activity in male and female hemodialysis patients.

BACKGROUND: Although previous studies reported that the prevalence of Fabry's disease was 0.16 - 1.2% in hemodialysis (HD) patients based on measurement of a-galactosidase A (alpha-Gal A) activity, few reports detected female patients by the screening for alpha-Gal A. Here we determined the prevalence of Fabry's disease not only in male but also in female HD patients by measuring alpha-Gal A. METHODS: Plasma alpha-Gal A was measured in 696 consecutive males (n = 401) and females (n = 295) on HD. Patients with low plasma alpha-Gal A were examined for leukocyte alpha-Gal A, and patients with low leukocyte alpha-Gal A underwent alpha-Gal A gene sequence analysis for possible mutations, and family survey. RESULTS: Among 15 patients with low plasma alpha-Gal A activity, 4 male patients with low leukocyte alpha-Gal A and 1 female patient revealing low plasma alpha-Gal A were detected in 696 HD patients (0.7% of total patients). 3 of these 5 patients were already diagnosed to have the classical type of Fabry's disease. The other 2 patients were newly diagnosed as Fabry's disease, and did not have typical manifestations of Fabry's disease other than renal failure and left ventricular hypertrophy. DNA analysis of these 2 newly diagnosed patients revealed that each had an alpha-Gal missense mutation, previously identified (E66Q, M2961). CONCLUSION: Fabry's disease should be considered in the etiology of unexplained end-stage renal disease. Not only affected males but also affected females undergoing HD patients can be readily diagnosed by alpha-Gal A activities and gene analysis. These patients and their family members may benefit from enzyme replacement therapy for Fabry's disease.

Adult↗

PubMed2004

Increased expression of humanin peptide in diffuse-type pigmented villonodular synovitis: implication of its mitochondrial abnormality.

OBJECTIVES: To define the pathogenesis of pigmented villonodular synovitis (PVNS), by searching for highly expressed genes in primary synovial cells from patients with PVNS. METHODS: A combination of subtraction cloning and Southern colony hybridisation was used to detect highly expressed genes in PVNS in comparison with rheumatoid synovial cells. Northern hybridisation was performed to confirm the differential expression of the humanin gene in PVNS. Expression of the humanin peptide was analysed by western blotting and immunohistochemistry. Electron microscopic immunohistochemistry was performed to investigate the distribution of this peptide within the cell. RESULTS: 68 highly expressed genes were identified in PVNS. Humanin genes were strongly expressed in diffuse-type PVNS, but were barely detected in nodular-type PVNS, rheumatoid arthritis, or osteoarthritis. Humanin peptide was identified in synovium from diffuse-type PVNS, and most of the positive cells were distributed in the deep layer of the synovial tissue. Double staining with anti-humanin and anti-heat shock protein 60 showed that humanin was expressed mainly in mitochondria. Electron microscopy disclosed immunolocalisation of this peptide, predominantly around dense iron deposits within the siderosome. CONCLUSIONS: Increased expression of the humanin peptide in mitochondria and siderosomes is characteristic of synovial cells from diffuse-type PVNS. Humanin is an anti-apoptotic peptide which is encoded in the mitochondrial genome. Present findings suggest that mitochondrial dysfunction may be the principal factor in pathogenesis of diffuse-type PVNS and that humanin peptide may play a part in the neoplastic process in this form of PVNS.

Arthritis, Rheumatoid↗

PubMed2004

Chelating of titanium by lactic acid in the water-soluble diammonium tris(2-hydroxypropionato)titanate(IV).

Stable water-soluble diammonium tris(2-hydroxypropionato)titanate(IV) [ammonium trilactatotitanate(IV)], (NH4)2[Ti(C3H4O3)3], was prepared in the crystalline form. According to the X-ray single-crystal diffraction data, this compound crystallizes in the cubic cell with a = 11.649(4) angstroms, space group P2(1)3 (no. 198), and has Z = 4 molecules per unit cell. The 13C NMR data and Raman and IR spectra support the determined structure. The absence of nonbonded functional groups restricts the formation of oligomers in contrast to the reported speciation of citratoperoxotitanate(IV) complexes.

Chelating Agents↗

PubMed2004

Oxidative stress reduces histone deacetylase 2 activity and enhances IL-8 gene expression: role of tyrosine nitration.

Oxidative stress is a characteristic of chronic inflammatory diseases. The reactive oxygen intermediate hydrogen peroxide (H(2)O(2)) is an important signaling molecule that modulates gene expression. We have demonstrated that H(2)O(2) significantly enhanced cytokine production in BEAS-2B cells, with a maximal effect at 4h. This did not result from enhanced NF-kappaB activation, but through decreased activity of histone deacetylase (HDAC)2. This results in increased inflammatory gene expression following acetylation of specific histone residues. Decreased HDAC2 activity was associated with tyrosine nitration status. Peroxynitrite and SIN-1, a peroxynitrite generator, were also able to reduce HDAC2 activity via tyrosine nitration. Our data suggest that oxidative stress contributes to worsening inflammation via reduction of HDAC2 activity through HDAC2 nitration. This novel mechanism of inflammation may be important in increasing the severity and chronicity of inflammatory diseases.

Cell Line↗

PubMed2004

Differential expression of IL-10 receptor by epithelial cells and alveolar macrophages.

BACKGROUND: Interleukin (IL)-10 is a pleiotropic cytokine with a broad spectrum of immunosuppressive and anti-inflammatory effects. IL-10 secretion from alveolar macrophages is defective in patients with asthma and lower concentrations of IL-10 are found in bronchoalveolar lavage (BAL) from asthmatic patients than in normal control subjects. Reduced IL-10 may result in exaggerated and more prolonged inflammatory responses in asthmatic airways. IL-10 acting through the IL-10 receptor (IL-10R) stimulates the transcription factors STAT1 and STAT3. METHODS: We investigated IL-10 and IL-10R expression in normal and asthmatic bronchial epithelium and BAL macrophages using reverse transcription-polymerase chain reaction, immunohistochemistry and Western blotting. The functional effect of IL-10 was examined using granulocyte-macrophage-colony stimulating factor, enzyme-linked immunosorbent assay and Western blotting for phosphorylated STAT1 and STAT3. RESULTS: IL-10 was not expressed in epithelial cells; furthermore these cells did not express the IL-10R and had no functional response to exogenous IL-10. Bronchial epithelial cells expressed variable levels of phosphorylated STAT1 and STAT3 with no change in expression between normal subjects and asthmatics. IL-10 protein and IL-10R expression was detected in alveolar macrophages from all subjects. CONCLUSION: Our study suggests that the bronchial epithelium is not a source of IL-10 and cannot respond to exogenous IL-10 because of a lack of IL-10R expression.

Adult↗

PubMed2004

A short daytime test using correlation dimension for respiratory movement in OSAHS.

In order to examine the pathology in patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS), the nonlinear properties of respiratory movement and breath-to-breath variations during resting wakefulness with eyes closed was investigated. Recording of the respiratory movement using inductive plethysmography was performed on 14 patients with OSAHS and 13 control subjects for 2 h in the supine position during daytime. To calculate the correlation dimension (D2) for respiratory movement, an algorithm proposed by Grassberger and Procaccia was applied. The indices of breath-to-breath variations were estimated. To calculate D2 and breath-to-breath variations, two different segments were selected (200 s each). The value of D2 for respiratory movement in patients with OSAHS was significantly greater than that in control subjects. In the case of > or = 2.0 of D2 for respiratory movement, the sensitivity and specificity of detecting the presence of OSAHS was 85.7% and 76.9%, respectively. On the basis of breath-to-breath variations, only the coefficient of variation of expiratory time for respiratory movement in patients with OSAHS was significantly greater than that in the control subjects. In conclusion, the measurements of correlation dimensions for respiratory movement with a brief period during wakefulness may be a useful index for identifying patients with obstructive sleep apnoea/hypopnoea syndrome.

Adult↗

PubMed2003

Phase I clinical study of a novel lipophilic platinum complex (SM-11355) in patients with hepatocellular carcinoma refractory to cisplatin/lipiodol.

SM-11355 is a platinum complex developed to treat hepatocellular carcinoma (HCC). It is administered via the hepatic artery, using a carrier, lipiodol, that consists of ethyl esters of iodized poppy seed oil. We have performed a phase I clinical trial of an SM-11355-lipiodol formulation in 11 HCC patients, in order to investigate the maximum allowable dose and to maximize the efficacy and safety of the drug in the treatment of HCC. The SM-11355 arterial infusion suspension was administered at doses of 6, 12 and 20 mg ml(-1) in a maximum lipiodol volume of 6 ml. An antitumour efficacy rating of complete response was achieved for one patient and a partial response rating was achieved for a second patient, giving an overall response rate of 18.2%. Anorexia, nausea and vomiting, pyrexia, thrombocytopenia and increases in AST, ALT and total bilirubin were observed as adverse effects, but each was transient and each patient had recovered completely by 4 weeks after drug administration. Hence, we concluded that the maximum allowable dose was not reached in this study. Overall, our results suggest that SM-11355 is effective in treating HCC and we suggest that the dose for early phase II trials should be 20 mg ml(-1).

Adult↗

PubMed2003

The effect of oxidative stress on histone acetylation and IL-8 release.

Acetylation of histone residues regulates the expression of inflammatory genes and is controlled by the activities of histone acetyltransferases (HAT) and histone deacetylases (HDAC). Analysis of histone acetylation in human cells is limited by the large numbers needed to perform activity assays or Western blotting. We have used flow cytometry to investigate changes in HAT and HDAC activities at the single cell level and to investigate the effect of hydrogen peroxide (H(2)O(2)) on histone H4 acetylation and cell-cycle progression. Using an anti-acetylated histone H4 antibody we show that H(2)O(2) induced a time-dependent increase in histone acetylation that was maintained for 12h. This was associated with increased IL-8 production. H(2)O(2) also affected cell-cycle progression. HAT activity was found to be highest in G2/M and equivalent in G0/G1 and S phases of the cell cycle. These data show that detection of acetylated histone residues at the single cell level using FACs may be a powerful new tool for the analysis of modulation of cell proliferation and gene transcription.

Acetylation↗

PubMed2003

Measuring subepithelial thickness using endobronchial ultrasonography in a patient with asthma: a case report.

The chronic inflammation of bronchial asthma is characterized by swelling of the subepithelial mucosa. However, it is difficult to assess subepithelial edema clinically. We report the case of a patient with asthma whose subepithelial edema was evaluated by endobronchial ultrasonography. Receiving montelukast 10 mg/day for 2 weeks, a 42-year-old man with mild, persistent asthma had his symptoms controlled by beta2-inhalation alone. Pretreatment endobronchial ultrasonography revealed subepithelial thickening in the right main stem bronchus, with a low absorption area suggestive of edema. Two weeks of montelukast therapy diminished the amount of subepithelial edema. Endobronchial ultrasonography is a promising technique for determining subepithelial edema in the asthmatic airway.

Adult↗

PubMed2003

Hyaluronic acid prevents peripheral nerve adhesion.

The purpose of this study was to clarify the effectiveness of hyaluronic acid (HA) in the prevention of scar formation after neurolysis using a rabbit model. In the first stage, the left sciatic nerve was exposed and elevated along a 3 cm section. Then, the surface of the neural bed was coagulated using a bipolar coagulator. Finally, the sciatic nerve was replaced and fixed to the neural bed with 8/0 nylon sutures, and the wound was closed. In the second stage, the adherent sciatic nerve was re-exposed after 6 weeks. In the neurolysis group, a simple neurolysis was performed. In the HA group, the neurolysis was performed in a surgical field coated with HA from the beginning to the end of the operation. In the steroid group, methyl prednisolone acetate was infiltrated at the end of the neurolysis. In the third stage, electrophysiological, histological and biomechanical measurements were taken 6 weeks after the second stage. While there was no significant difference between the HA and the steroid groups, the electrophysiological functions of the HA and steroid groups were significantly better than that of the neurolysis group. Histology showed that the formation of intraneural and extraneural scar tissue was lowest in the HA group, followed by the steroid and neurolysis groups. The tensile strength required to strip the sciatic nerve from the neural bed of the HA group was significantly less than that of the neurolysis group. However, there was no significant difference between the steroid and neurolysis groups. In conclusion, HA effectively reduced scar formation after neurolysis.

Adjuvants, Immunologic↗

PubMed2003

Powdery mildew (Sphaerotheca fuliginea) resistance in melon is selectable at the haploid level.

The major cause of powdery mildew in melons (Cucumis melo L.) is the fungus Sphaerotheca fuliginea. There are several cultivar- and season-specific races of this fungus. In order to control powdery mildew, it is important to introduce resistance to fungal infection into new cultivars during melon breeding. Haploid breeding is a powerful tool for the production of pure lines. In this study, it was investigated whether powdery mildew resistance could be manifested at the haploid level from two disease-resistant melon lines, PMR 45 and WMR 29. the effects of various races of S. fuliginea on diploid and haploid plants of PMR 45 and WMR 29 and of a disease-susceptible line, Fuyu 3 were measured. The responses of haploid and diploid plants to powdery mildew were identical. In addition, haploids that were generated from hybrids between Fuyu 3 and disease-resistant lines were examined. Seven out of 13 haploids from a Fuyu 3xPMR 45 cross and 10 out of 12 haploids from a Fuyu 3xWMR 29 cross were classified as resistant plants because they showed the same responses as their disease-resistant diploid parents to the various fungal races. These results indicate that resistance in PMR 45 and WMR 29 is selectable at the haploid level. All of the plant responses were observed by microscopy. A possible mechanism for generating powdery mildew resistance in two different melon lines is discussed.

Cucumis melo↗

PubMed2003

Angiotensin-converting enzyme inhibitor withdrawal and ACE gene polymorphism.

AIMS: Withdrawal of angiotensin-converting enzyme (ACE) inhibitors may affect the progression of chronic renal failure and an insertion/deletion (I/D) polymorphism of the ACE gene may influence it. METHODS: We retrospectively collected patients with chronic glomerulonephritis and benign nephrosclerosis who discontinued ACE inhibitor use. The relationship between the decline of renal function after the withdrawal and the influencing factors such as ACE gene polymorphism, blood pressure and proteinuria were evaluated using multiple regression analysis. RESULTS: Forty-two patients (initial serum creatinine 0.5 - 6.5 mg/dl) had been treated and discontinued ACE inhibitor use. Only patients with the II or DI genotypes of the ACE gene developed the deterioration of renal function, starting at 2 months after the withdrawal. Stepwise regression analysis revealed that the level of proteinuria after the withdrawal, presence of the insertion of ACE gene and serum creatinine level at the time of withdrawal mainly influenced the decline of renal function after the withdrawal (adjusted R2 = 0.48). CONCLUSION: Withdrawal of ACE inhibitor causes the deterioration of renal function in patients with the II or DI genotypes, high proteinuria after the withdrawal, and high serum creatinine level at the withdrawal, which probably causes the rebound increase in serum ACE activity.

Aged↗