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Biomedical subjects

K Katoh

Publications and source records attributed to K Katoh.

At least 73 records · Page 4Linked to original sources
PubMed1999

A patient with preclinical Cushing's syndrome and excessive DHEA-S secretion having unilateral adrenal carcinoma and contralateral adenoma.

We report a case of preclinical Cushing's syndrome in a 54-year-old male associated with bilateral adrenocortical tumours. Physical findings and general laboratory data were unremarkable except for mild hypertension (158/90 mmHg) and impaired glucose tolerance. Endocrinological evaluation revealed the presence of autonomous cortisol secretion including unsuppressible serum cortisol by 8 mg dexamethasone test (11 microg/dl), high serum DHEA-S (3580 ng/ml, normal: 400-3500) and increased urinary 17-KS excretion (31.0-35.8 mg/day, normal: 5.8-21.3). CT scan demonstrated the presence of tumours in both adrenals and bilateral adrenalectomy was subsequently performed. Histological examination of the resected specimens revealed an adrenocortical carcinoma on the right side and an adenoma on the left side with noticeable cortical atrophy in non-neoplastic adrenals. Immunohistochemical study of steroidogenic enzymes demonstrated that all the steroidogenic enzymes involved in cortisol biosynthesis were expressed in both right and left adrenal tumours. Enzymatic activities of 21, 17alpha, 18, 11beta-hydroxylases were detected in both right and left adrenals except for the absence of 11beta-hydroxylase activity in the left adrenal adenoma. Results of in vitro tissue steroidogenesis examined in short-term tissue culture of the specimens revealed no significant differences between carcinoma and adenoma in cortisol production, but the production of adrenal androgens in carcinoma was significantly higher than that in adenoma, which may indicate the importance of evaluating adrenal androgen levels in patients with adrenocortical neoplasms.

17-Ketosteroids↗
PubMed1999

Prediction of life expectancy in patients with primary pulmonary hypertension. A retrospective nationwide survey from 1980-1990.

Primary pulmonary hypertension (PPH) is a progressive disease of unknown etiology usually followed by death within 5 years after diagnosis. Although heart-lung or lung transplantation is now offered to patients with advanced PPH, adequate criteria assessing an accurate prediction of life expectancy in PPH has been difficult to establish. The aims of this study were to identify the characteristic features associated with a poor prognosis in patients with PPH, and to attempt to establish an individual prognostic index that predicts with great accuracy survival or death of PPH after one year, thereby helping to define criteria for patient selection for transplantation. In 1991, a retrospective nation-wide survey on PPH was conducted in Japan, and the clinical and cardiorespiratory variables of 223 PPH cases (female; 144, male; 79) in the period from 1980-1990 were obtained. The mean pulmonary arterial pressure (PPA) was 57.5+/-17.2 mm Hg (mean+/-SD), and the overall median survival time was 32.5 months since the first diagnostic catheterization. The characteristic features of 61 patients who died within one year of catheterization (Nonsurvivors group) were compared to 141 patients who survived one year or more from the time of catheterization (Survivors group). Among several clinical and cardiorespiratory variables, heart rate, PPA, right atrial pressure (PRA), stroke volume index (SI), pulmonary vascular resistance, and partial pressure of carbon dioxide (PaCO2) were significantly different between the two groups. As the independent factors, PPA, PRA, SI, and PaCO2 were selected for the multiple logistic analysis. Using a 0.7 probability cut-point to separate Nonsurvivors from Survivors, 84.6% of Nonsurvivors and Survivors could be correctly predicted from this logistic regression equation. Predictive equations like the present preliminary one can be used in the future to better assess life expectancy in patients with PPH in whom transplantation will be considered.

Adolescent↗
PubMed1999

Hypnagogic imagery and EEG activity.

The relationships between hypnagogic imagery and EEG activity were studied. 7 subjects (4 women and 3 men) reported the content of hypnagogic imagery every minute and the hypnagogic EEGs were classified into 5 stages according to Hori's modified criteria. The content of the hypnagogic imagery changed as a function of the hypnagogic EEG stages.

Acoustic Stimulation↗
PubMed1999

The FLS mouse: a new inbred strain with spontaneous fatty liver.

BACKGROUND AND PURPOSE: A new strain of mouse, named FLS (fatty liver Shionogi), which develops spontaneous fatty liver without obesity, was established by inbreeding. Morphologic, physiologic, and genetic characterization of the strain was done. METHODS: Characteristics of male FLS mice were compared with those of the sister strain, dd Shionogi (DS), which does not develop spontaneous fatty liver. A genetic cross experiment was performed by mating FLS with C3H/He/Shi mice. RESULTS: The hepatocytes of neonatal FLS mice contained fine lipid droplets throughout the lobules, and large lipid droplets appeared as mice aged. Liver triglyceride concentrations of FLS mice were fivefold higher than those of DS mice, but serum lipid concentrations and the lipoprotein profile did not indicate abnormalities. Higher plasma aspartate transaminase and alanine transaminase activities in FLS, compared with DS mice, suggested hepatocellular lesions. The genetic cross experiment suggested that the fatty liver formation is a complex polygenic trait. CONCLUSION: The FLS mice develop a progressive hepatic steatosis without obesity and diabetes. The FLS mouse might be a good model for investigating hepatic disorders accompanied by fatty liver unrelated to alcoholism or obesity.

Adipose Tissue↗
PubMed1998

Transcriptional activation of the alternative oxidase gene of the fungus Magnaporthe grisea by a respiratory-inhibiting fungicide and hydrogen peroxide.

Alternative oxidase (AOX) is dramatically induced when the fungus Magnaporthe grisea is incubated with the fungicide SSF-126, which interacts with the cytochrome bc1 complex in the electron transport system of mitochondria. A full-length cDNA for the alternative oxidase gene (AOX) was obtained, and the deduced amino acid sequence revealed marked similarity to other AOXs, but lacks two cysteine residues at corresponding sites which are conserved in plant AOXs and play essential roles in the post-translational regulation. Northern blot experiments showed that treatment of M. grisea cells with SSF-126 induces accumulation of AOX mRNA in a dose-dependent manner, and the level was correlated with the activity of alternative respiration. H2O2 also induced the accumulation of the transcript with a short half-life (<15 min). Nuclear run-on experiments showed that the AOX gene was transcribed constitutively in unstimulated cells. Cycloheximide did not change the basal level of transcription, but induced the accumulation of the transcript, indicating that active degradation of the transcript occurs by factor(s) sensitive to cycloheximide. On the other hand, SSF-126 enhanced the transcriptional activity of AOX gene threefold compared to that of control cells, and H2O2 was also potent for enhancement of the transcription. From these results, it is concluded that the respiratory inhibitor-dependent activation of the transcription is a primary determinant for the induction of alternative respiration in M. grisea. Because we have previously shown that SSF-126 treatment of M. grisea mitochondria induced the generation of superoxide, active oxygen species are thought to be signal mediators to activate AOX gene transcription in M. grisea.

Amino Acid Sequence↗
PubMed1998

Functional transitions in myosin: formation of a critical salt-bridge and transmission of effect to the sensitive tryptophan.

For analyzing the mechanism of energy transduction in the "motor" protein, myosin, it is opportune both to model the structural change in the hydrolytic transition, ATP (myosin-bound) + H2O --> ADP.Pi (myosin-bound) and to check the plausibility of the model by appropriate site-directed mutations in the functional system. Here, we made a series of mutations to investigate the role of the salt-bridge between Glu-470 and Arg-247 (of chicken smooth muscle myosin) that has been inferred from crystallography to be a central feature of the transition [Fisher, A. J., Smith, C. A., Thoden, J. B. , Smith, R., Sutoh, K., Holden, H. M., & Rayment, I. (1995) Biochemistry 34, 8960-8972]. Our results suggest that whether in the normal, or in the inverted, direction an intact salt-bridge is necessary for ATP hydrolysis, but when the salt-bridge is in the inverted direction it does not support actin activation. Normally, fluorescence changes result from adding nucleotides to myosin; these signals are reported by Trp-512 (of chicken smooth muscle myosin). Our results also suggest that structural impairments in the 470-247 region interfere with the transmission of these signals to the responsive Trp.

Animals↗
PubMed1998

Different distributions of immunoreactive S100-alpha and S100-beta protein expression in human breast cancer.

BACKGROUND AND OBJECTIVES: Although the localization of S100 protein in breast carcinoma has previously been studied, the immunohistochemical expression of the S100-alpha and -beta subunits has not been examined. METHODS: Immunohistochemical staining for S100-alpha and S100-beta proteins was performed on 72 benign breast lesions and 72 infiltrating ductal carcinoma of the breast. Noncross-reactive anti-S100-alpha and anti-S100-beta antibodies purified by affinity chromatography were used in the studies. RESULTS: More than 30% of the epithelial cells comprising all the benign lesions were either S100-alpha or S100-beta positive. In breast carcinoma cases, however, >30% of malignant cells were S100-alpha positive in 70/72 cases (97.2%), whereas the number of S100-beta positive cells exceeded 30% in only 3/72 cases (4.0%). CONCLUSIONS: Immunohistochemical staining for S 100-alpha and S100-beta proteins may help to differentiate benign proliferative breast lesions from breast cancers in difficult cases.

Breast Neoplasms↗
PubMed1998

Preservation of the knee joint in limb salvage of osteosarcoma in the proximal tibia. A case report.

A 12-year-old boy with osteosarcoma in the proximal tibia underwent a successful limb-saving operation with preservation of the epiphyseal and articular cartilage of the proximal tibia as a result of his remarkable response to chemotherapy. There was no evidence of tumour invasion to the adjacent physis, as demonstrated by image findings. The bone defect was reconstructed using autoclaved autogeneous bone with a vascularized fibula. The patient exhibits excellent function of the affected limb, and the knee joint remains disease-free 55 months postoperatively.

Bone Neoplasms↗
PubMed1998

Functional magnetic resonance imaging during recognition of written words: Chinese characters for concrete objects versus abstract concepts.

An attempt was made to apply functional magnetic resonance imaging (fMRI) to reveal cortical areas activated upon presentation of two groups of Chinese characters in six normal right-handed, male, Japanese subjects. Presentation of the characters representing 'abstract concepts' activated the bilateral occipital region without a significant difference between the bilateral occipital and temporal regions. Presentation of the characters representing 'concrete objects' resulted in significantly stronger activation in the left occipital and temporal regions. These results suggest that recognition of concrete characters involves a stronger initial process in the left occipital temporal cortices than recognition of abstract characters.

Adult↗
PubMed1998

Functional magnetic resonance imaging during recognition of written words: Chinese characters for concrete objects versus abstract concepts.

An attempt was made to apply functional magnetic resonance imaging (fMRI) to reveal cortical areas activated upon presentation of two groups of Chinese characters in six normal right-handed, male, Japanese subjects. Presentation of the characters representing 'abstract concepts' activated the bilateral occipital region without a significant difference between the bilateral occipital and temporal regions. Presentation of the characters representing 'concrete objects' resulted in significantly stronger activation in the left occipital and temporal regions. These results suggest that recognition of concrete characters involves a stronger initial process in the left occipital temporal cortices than recognition of abstract characters.

Adult↗
PubMed1998

Human Plasma Fibronectin Mediates Adhesion of U937 Cells by RGD and CS1.

Fibronectin specifically binds to U937 cells (monocytic cell line) in a dose-dependent manner. The specific receptors for the RGD sequence have been identified as alphainfinity 5beta infinity 1wedge alpha infinity: IIb& beta infinity 3, and that for CS1 has been defined as alpha infinity 4& beta infinity 1. RGDS, CS1 peptide, and two peptides together showed similar inhibitory activities on this adhesion, while the 29-kD dispase-digested fragment of the C-terminal heparin-binding domain did not. Thus, the adhesion of fibronectin to U937 cells is mainly mediated by RGDS in the cell-binding domain and CS1 in the alternatively spliced region. Flow cytometry using monoclonal antibodies revealed expressions of alpha infinity 3& beta 1 infinity, alpha4 & beta infinity 1, and alpha infinity 5 beta 1, and not expression of alpha infinity 2 beta infinity 1. Adhesion of U937 cells to fibronectin-coated wells is specific and is inhibited by anti-alpha infinity 4 beta infinity 1 and anti- alpha infinity 5 beta infinity 1 monoclonal antibodies. The IC-50 for anti-alpha infinity 5 beta infinity 1 antibody was almost a log lower than the value for anti-alpha infinity 4 beta infinity 1 antibody. These results demonstrated that interactions of RGDS and CS1 sequence of fibronectin with alpha infinity 5 beta infinity 1 and alpha infinity 4 beta infinity 1& on U937 cells were required for the adhesion of U937 cells to fibronectin. These results may provide further information to understand the mechanism(s) of tumor cell adhesion and atherogenesis.

Journal Article↗
PubMed1998

Diagnostic value of hemostatic parameters in bone marrow transplant-associated thrombotic microangiopathy.

We investigated hemostatic parameters in a prospective study of 16 patients who received bone marrow transplants (BMT). We found a significant rise in the levels of fibrinogen, plasmin-alpha2 antiplasmin inhibitor complex, tissue-plasminogen activator.plasminogen activator inhibitor complex (t-PA.PAI), von Willebrand factor antigen, and thrombomodulin on day 14 after transplant compared with values before transplant. Protein C and thrombin-antithrombin III levels did not change significantly. No significant changes in prothrombin time ratio, activated partial thromboplastin time, or protein S were detected. Patients who had grades II-IV graft-versus-host disease (GVHD) (n = 6) showed a significantly higher level of t-PA.PAI on day 14 compared with those with grades 0-I GVHD (n = 10) (P = 0.0062). Three patients with grades II-IV GVHD developed thrombotic microangiopathy (TMA) on days 19, 19 and 62. In these patients, we noted significantly lower levels of fibrinogen (P = 0.0383), and significantly higher levels of t-PA.PAI (P = 0.0008) and thrombomodulin (P = 0.0001) on day 14 compared with those patients who did not develop TMA. These results suggest that prothrombotic states and endothelial damage may be caused by the conditioning regimen and/or acute GVHD during BMT; thrombomodulin values on day 14 post BMT may be useful in surveillance for TMA because of endothelial cell injury.

Adolescent↗
PubMed1998

Isolation and contraction of the stress fiber.

Stress fibers were isolated from cultured human foreskin fibroblasts and bovine endothelial cells, and their contraction was demonstrated in vitro. Cells in culture dishes were first treated with a low-ionic-strength extraction solution and then further extracted using detergents. With gentle washes by pipetting, the nucleus and the apical part of cells were removed. The material on the culture dish was scraped, and the freed material was forced through a hypodermic needle and fractionated by sucrose gradient centrifugation. Isolated, free-floating stress fibers stained brightly with fluorescently labeled phalloidin. When stained with anti-alpha-actinin or anti-myosin, isolated stress fibers showed banded staining patterns. By electron microscopy, they consisted of bundles of microfilaments, and electron-dense areas were associated with them in a semiperiodic manner. By negative staining, isolated stress fibers often exhibited gentle twisting of microfilament bundles. Focal adhesion-associated proteins were also detected in the isolated stress fiber by both immunocytochemical and biochemical means. In the presence of Mg-ATP, isolated stress fibers shortened, on the average, to 23% of the initial length. The maximum velocity of shortening was several micrometers per second. Polystyrene beads on shortening isolated stress fibers rotated, indicating spiral contraction of stress fibers. Myosin regulatory light chain phosphorylation was detected in contracting stress fibers, and a myosin light chain kinase inhibitor, KT5926, inhibited isolated stress fiber contraction. Our study demonstrates that stress fibers can be isolated with no apparent loss of morphological features and that they are truly contractile organelle.

Actin Cytoskeleton↗
PubMed1998

Quinolone-resistant mutations of DNA gyrase increase sensitivity to acriflavine.

DNA gyrases were constructed to possess the quinolone-resistant (D87N in GyrA or K447E in GyrB) and acrB (S759R-R760C in GyrB) mutations and their sensitivities to acriflavine and oxolinic acid were examined. Both quinolone-resistant mutations in GyrA and GyrB increased acriflavine sensitivities in the supercoiling assay irrespective of the co-presence of the acrB mutation. In the DNA binding assay, however, the hypersensitvity caused by the GyrB (K447E) mutation was observed only in the co-presence of the acrB mutation; the presence of the acrB mutation, which not affecting acriflavine sensitivity, reduces the extent of DNA binding, as reported previously. Thus, the quinolone-resistant mutation site in GyrB is likely to be involved in DNA binding which is not detectable in acrB+ gyrase. Furthermore, oxolinic acid was found to enhance DNA binding of the gyrase having GyrB (acrB-K447E), supporting a recent proposal that quinolone binding to the DNA-gyrase complex does not require DNA breakage.

4-Quinolones↗
PubMed1998

Arterial and mixed venous oxygen desaturation during incremental exercise in patients with chronic pulmonary disease.

We evaluated arterial and mixed venous oxygen desaturation during symptom-limited exercise in patients with chronic pulmonary disease. Patients were divided into five groups according to disease: [chronic pulmonary emphysema (CPE), chronic bronchitis (CB), pulmonary tuberculosis sequalae (TB-seq), fibrosing lung disease (FLD), and pulmonary vascular disease (PVD)]. There were no significant difference in the values of arterial (PaO2) and mixed venous (PvO2) oxygen tension before and at the end of exercise among the five groups, whereas absolute decreases in PvO2 were significantly larger in PVD and FLD. The changes in PvO2 were similar to the changes in the coefficient of oxygen delivery (COD) which is equal to oxygen transport divided by oxygen consumption. These results suggest that the relative decrease in oxygen transport during exercise due to the high ratio of oxygen extraction by tissues is an important factor to determine decreases in PvO2 in pulmonary hypertensive disease and fibrosing lung disease.

Aged↗