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S Katayama

Publications and source records attributed to S Katayama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Size-dependent in vivo growth potential of adult rat hepatocytes.

The present study was performed to determine whether hepatocytes show a size-dependent growth in vivo using as a growth assay system, a retrorsine/partial hepatectomy model of dipeptidyl dipeptidase IV-deficient (DPPIV(-)) mutant Fischer rats. Nearly pure populations of small hepatocytes (SHs) and parenchymal hepatocytes (PHs) were prepared from DPPIV(+) rats. The same number of these SHs and PHs was transplanted into the liver of retrorsine-treated and two-thirds partial hepatectomized DPPIV(-) rats. At 21 days after transplantation, colonies derived from donor hepatocytes were detected as DPPIV(+) cells by enzyme histochemistry. SHs were approximately three times more proliferative than PHs (673 +/- 25 cells/colony versus 226 +/- 10 cells/colony, mean +/- SE). SHs were subfractionated by a fluorescence-activated cell sorter into SH-R2s and SH-R3s. SH-R3s showed a lower extent of granularity and autofluorescence, and a smaller size than SH-R2s that showed characteristics similar to PHs. The growth potential of SH-R3s assayed as above was approximately three times higher than that of SH-R2s (1,101 +/- 46 cells/colony versus 341 +/- 13 cells). These results indicate that the in vivo growth potential of hepatocytes is heterogeneous and is correlated with their size, and the extent of their granularity and autofluorescence.

Albumins↗
PubMed2001

Second nation-wide study of atherosclerosis in infants, children and young adults in Japan.

This paper reports the results of the second nation-wide cooperative study of atherosclerosis in young Japanese, aged from 1 month to 39 years, who were autopsied between 1991 and 1995. Atherosclerotic lesions in 1066 aortas and 974 coronary arteries were classified into fatty streaks, fibrous plaques and complicated lesions and quantificated with the point-counting method. The results of this study were compared with those of the former study, which was conducted 13 years earlier in almost the same fashion as this study. Atherosclerosis of aorta, which was determined by surface involvement (SI) of atherosclerotic lesions and atherosclerotic index (AI), increased with age in both sexes of the former and the present studies and their tendency for the progression of the extent of atherosclerotic lesions appeared to be similar. In the coronary arteries, the mean values of SI and AI in the males of the present study were greater significantly than those in the male of the former studies and in the female of the both studies in the third and fourth decades. This difference suggests that atherosclerotic lesions are increasing in young Japanese males. It also suggests that these subjects may be increasingly susceptible to atherosclerotic cardiovascular disease with increasing age.

Adolescent↗
PubMed2001

A questionnaire for neurological symptoms in patients with diabetes--cross-sectional multicenter study in Saitama Prefecture, Japan.

This study was designed to investigate the prevalence of neurological symptoms in diabetic patients living in Saitama Prefecture, Japan using 13-item questionnaire. A total of 6472 outpatients with diabetes (3417 men and 3055 women) were recruited from 100 centers. Mean age and mean disease duration were 60.9-year old and 10.4 years, respectively. The questionnaire for monitoring of neurological symptoms was completed at the clinic or hospital visited, and Achilles' tendon reflex, ophthalmologic, blood and urinary examinations were also performed. Of the 6472 patients, 84.8% suffered from a mean of 3.3+/-2.2 neurological symptoms. However, half of these symptoms were not considered to be those of diabetic neuropathy by attending physicians. "Feeling as if a piece of paper is attached to the sole of the foot," "stinging and prickling sensations in feet," and "pain in feet" were the most common symptoms of diabetic neuropathy. The prevalence of diabetic neuropathy as determined by attending physician increased with disease duration and worse control of diabetes. This study found that the majority of diabetics were suffered from neurological symptoms, although half of such symptoms were not considered to be those of diabetic neuropathy by physicians. Furthermore, it is important for diabetics to be diagnosed and treated earlier to prevent progression to severe neuropathic complications by means of optimal glycemic control and use of some chemicals such as aldose reductase inhibitor, and to develop this study to evaluate the efficacy of treatments.

Aged↗
PubMed2001

Diabetic ketoacidosis in a case of pheochromocytoma.

A 31-year-old woman was admitted to our hospital because of diabetic ketoacidosis (DKA). Ultrasound sonography revealed the existence of the left adrenal tumor and endocrinological examinations established a diagnosis of pheochromocytoma. She had been healthy and there was no evidence for gestational diabetes in her personal history. Characteristic features were not found in her tumor size and the catecholamine levels as compared with typical cases of pheochromocytoma. An overwhelming secretion of catecholamine might suppress insulin secretion, as evidenced by the improvement after the resection of the tumor. However, a significant insulin resistance continued after tumor resection. Obesity and the heterozygosity of beta3-adrenergic receptor gene (Try64Arg) might play a role in insulin resistance, which resulted in DKA at least in part. Literature survey revealed four cases of DKA in the patients with pheochromocytoma including ours, three of which were Japanese. Pancreatic capacity to secrete insulin has been reported to be less than Caucasians, which might be another reason for DKA. Thus, we speculate that both suppressed insulin secretion and insulin resistance deteriorated by obesity or other factor(s) such as abnormality in beta3 adrenergic receptor probably depress beta-cell function resulting in abnormal metabolic imbalance such as DKA.

Adrenal Gland Neoplasms↗
PubMed2001

Phosphorylation of Mei2 and Ste11 by Pat1 kinase inhibits sexual differentiation via ubiquitin proteolysis and 14-3-3 protein in fission yeast.

Fission yeast Pat1 kinase inhibits sexual differentiation by phosphorylating the meiotic inducer Mei2 and the transcription factor Ste11. Here, we show how Pat1 downregulates these proteins. Mei2 is degraded via a ubiquitin-proteasome pathway in a phosphorylation-dependent fashion. The E2 Ubc2 and the E3 Ubr1 are required for this proteolysis. In addition, Pat1 negatively regulates Ste11 via Rad24/14-3-3, thereby repressing mei2+ transcription. The Pat1 phosphorylation sites of Ste11 match the consensus recognition sequence for 14-3-3. Rad24 binds preferentially to phosphorylated Ste11, and this binding results in inhibition of the transcriptional activation capacity of Ste11. Overall, therefore, these results show that Pat1 coordinates concerted molecular mechanisms that govern the sexual differentiation developmental decision.

14-3-3 Proteins↗
PubMed2001

Abnormal signals on proton density-weighted MRI of the superior cerebellar peduncle in progressive supranuclear palsy.

OBJECTIVE: To assess MRI signal abnormalities of the superior cerebellar peduncle (SCP) in progressive supranuclear palsy (PSP) patients. MATERIAL AND METHODS: Signal changes were examined on proton density-weighted images (PDWI) and on T2-weighted images (T2WI) of SCP in 9 PSP patients, and findings were compared to those in 20 Parkinson's disease patients and 20 age-matched control subjects. RESULTS: We observed effacement or lack of clarity of the low signal on PDWI in SCP in 4 of 9 PSP patients, but not in any of the Parkinson's disease patients or control subjects. These signal changes were not observed on T2WI. CONCLUSIONS: The signal changes on PDWI may be a specific finding reflecting demyelination and gliosis of SCP in PSP. Our findings suggest that evaluation of SCP on PDWI may be helpful in the diagnosis of PSP patients.

Aged↗
PubMed2001

The relationship between alphaB-crystallin and neurofibrillary tangles in Alzheimer's disease.

AlphaB-crystallin is known as a small heat shock protein with a cytoprotective function. This study was undertaken to investigate the relationship between alphaB-crystallin and changes seen in Alzheimer's disease. The distribution and immunohistochemical characteristics of alphaB-crystallin positive neurones in the cerebral cortices of 4 patients with Alzheimer's disease were examined. AlphaB-crystallin positive neurones were mainly distributed in the limbic and paralimbic regions, namely parahippocampal gyrus, fusiform gyrus, cingulate cortex, middle and superior frontal gyrus, and insular cortex, which corresponded to commonly affected regions in Alzheimer's disease. Moreover, such neurones were present predominantly in the III or V layer of the cerebral cortex. The number of alphaB-crystallin positive neurones increased in parallel with the neuronal loss. Logistic regression analysis revealed a significant relation between the density of alphaB-crystallin positive neurones and that of extracellular neurofibrillary tangles (NFTs), with a correlation coefficient (r) of 0.57 and P < 0.0001 in 14 regions of the cerebral cortex. In contrast, the relation was not statistically significant between the density of alphaB-crystallin positive neurones and that of classical senile plaques, diffuse plaques or intracellular NFTs. Modified Gallyas-Braak (GB) staining on alphaB-crystallin positive neurone demonstrated several patterns of the structures: faint GB positive structures in the swollen perikaryon with straight neurites, fine granules compressed and contorted into fuzzy bundles, intensely GB positive filamentous structures together with fine granules and very intensely GB positive ring-like NFTs in a swollen perikaryon with curved neurites. In positive neurones, the density of ring-like NFTs correlated with that of atrophic perikaryon, or bent neurites and a decrease in the immunoreactivity of alphaB-crystallin. These data suggest that a close relationship exists between the appearance of alphaB-crystallin in neurones, extracellular NFTs, and neurofibrillary formation in alphaB-crystallin positive neurones in Alzheimer brain.

Aged↗
PubMed2001

A comparison of middle latency auditory-evoked response in obstructive sleep apnea syndrome before and after treatment.

The ascending reticular activating system seems to be affected by nocturnal hypoxia in obstructive sleep apnea syndrome (OSAS) patients so that their vigilance level is decreased. To evaluate the change in vigilance level in OSAS patients, polysomnography, the Epworth Sleepiness Scale and middle latency auditory-evoked responses (MLR) were measured before and after treatment in seven men with OSAS (mean age 45.4 +/- 12.9 years, mean body mass index 33.3 +/- 7.6 kg/m2). After treatment there was significant improvement of nocturnal hypoxia in OSAS. Peak amplitude of P1 in MLR increased after treatment. There was also improvement of the electrical field distribution of MLR on the scalp. The results suggest that the decreased vigilance level in OSAS patients is reversible with treatment.

Arousal↗
PubMed2001

The ligands/activators for peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma increase Cu2+,Zn2+-superoxide dismutase and decrease p22phox message expressions in primary endothelial cells.

We examined the effects of a variety of ligands/activators of the peroxisome proliferator-activated receptor (PPAR) on the expression of the superoxide scavenger enzyme, Cu2+,Zn2+-superoxide dismutase (CuZn-SOD), and the superoxide generating enzyme nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase in primary cultures of human umbilical vein endothelial cells (HUVEC) and human aorta endothelial cells (HAEC). Our data show that 3 types of PPARs, PPARalpha, PPARbeta/delta/Nuc1, and PPARgamma are expressed in endothelial cells. Bezafibrate, which is a ligand/activator for PPARalpha, increased the CuZn-SOD gene expression and protein levels in endothelial cells. Troglitazone and pioglitazone, which are ligands/activators for PPARgamma, also induced PPARalpha gene and protein expression and increased CuZn-SOD gene expression and protein levels in addition to increasing PPARgamma gene and protein expression in endothelial cells. Moreover, with treatment of monounsaturated and polyunsaturated fatty acids (PUFA), the CuZn-SOD mRNA levels were positively correlated with PPARalpha mRNA levels (r = .872, P < .0001) in primary endothelial cells. In addition, the phorbol myristate acetate (PMA)-stimulated or PMA-nonstimulated 22-kd a-subunit (p22phox) mRNA levels and 47-kd a-subunit (p47phox) protein levels in NADPH oxidase were decreased by treatment with PPARalpha and PPARgamma ligands/activators. These results suggest that PPARalpha and PPARgamma gene and protein expression in endothelial cells may play a physiologic role as radical scavengers, although the details of these mechanisms remain to be established.

Cells, Cultured↗
PubMed2001

Modulation of reactive oxygen species in endothelial cells by peroxynitrite-treated lipoproteins.

Peroxynitrite has been implicated in the oxidative modification of low-density lipoprotein (LDL) particles, and nitrotyrosine residues in the LDL have been detected in atherosclerotic plaques. Studies have suggested that lipoproteins modified by peroxynitrite lead to the onset of atherosclerotic vascular disease. We therefore prepared in vitro lipoproteins oxidatively modified by peroxynitrite (NO(2)-lipoprotein) and investigated the effect of NO(2)-lipoprotein on the viability of cultured endothelial cells. After exposure of a high-density lipoprotein (HDL) to peroxynitrite, some intermolecular complexes of apolipoproteins in HDL were detected on immunoblotting with monoclonal antibodies against apolipoprotein AI and AII, suggesting that nitration of HDL by peroxynitrite causes intermolecular cross-linking of the apolipoproteins in the particles. Treatment with 1 mM peroxynitrite increased the 3-nitrotyrosine level to 28.5 mmol/mol of tyrosine residues in the prepared NO(2)-HDL, as quantitated by HPLC, and the amount in NO(2)-lipoprotein depended on the peroxynitrite concentration. HDL exhibited a shorter lag phase and the reaction plateaued more rapidly than that with LDL. To clarify whether or not NO(2)-lipoproteins affect the function of endothelial cells, we first examined the viability of cultured human aortic endothelial cells (HAECs) exposed to NO(2)-lipoproteins. Incubation with either NO(2)-HDL or NO(2)-LDL significantly reduced the HAEC viability at 72 h. The results of RT-PCR and Western blotting showed that NO(2)-HDL markedly suppressed at 48 h not only the expressed levels of mRNA and protein but also the activity of catalase in HAECs. In contrast, NO(2)-LDL significantly reduced the expression and activity of Cu(2+),Zn(2+)-superoxide dismutase (CuZn-SOD) in the cells. Neither NO(2)-HDL nor NO(2)-LDL interfered with nitric oxide production or expression of cyclooxygenases and NADPH oxidase in HAECs. Increased radical production in NO(2)-lipoprotein-treated HAECs implied that reactive oxygen species such as superoxide anions and hydroxyl radicals may contribute to the mechanism of the toxic effect induced in endothelial cells by NO(2)-lipoprotein. Overall, NO(2)-lipoprotein may lead to deterioration of the vascular function through these endothelial cell responses.

Arteriosclerosis↗
PubMed2001

Enhanced formation of azoxymethane-induced colorectal adenocarcinoma in gammadelta T lymphocyte-deficient mice.

T cell receptor (TCR) gammadelta-positive T lymphocytes, which are localized mostly within the intraepithelial space of intestinal epithelium, have been suggested to play a role in maintaining the normal configuration of intestinal epithelium. However, the role of TCRgammadelta-positive T lymphocytes in the formation and progression of colorectal adenocarcinoma that originates from colorectal epithelial cells remains to be elucidated. In this study, TCRalphabeta and TCRgammadelta-positive T lymphocyte-deficient mice (homozygous TCRa and TCRd-gene knockout mice) and the background wild-type mice were administered azoxymethane, and the formation of macroscopic tumors and microscopic aberrant crypt foci in colorectal mucosa were compared among the three types of mice. Well-differentiated adenocarcinoma appeared 5 months after 5 administrations of azoxymethane (10 mg/kg weight) only in a few TCRd -gene knockout mice and the frequency of the carcinoma-bearing mice was increased at 7 and 9 months after the administration. Aberrant crypt foci were also detected in the colorectal mucosa of TCRd -gene knockout mice to a greater extent than in colorectal mucosa of TCRa-gene knockout mice 1 month after the azoxymethane administration. These results suggest that TCRgammadelta-positive T lymphocytes, which are present mainly in the intraepithelial space, play a role in suppression of the formation and progression of colorectal adenocarcinoma in mice.

Adenocarcinoma↗
PubMed2001

Actigraph analysis of diurnal motor fluctuations during dopamine agonist therapy.

BACKGROUND: Generally, clinicians use rating scales or descriptive writing to characterize diurnal changes in motor signs and symptoms in Parkinson's disease (PD); however, these ratings are subjective and are not easily reproducible. OBJECTIVE: To examine the usefulness of actigraphy as an objective indicator of akinesia by long-term, continuous measurement of limb motor activity (MA), visualize 24-hour circadian profiles of akinesia, and quantitatively detect cabergoline (CBG) efficacy in both hospitalized patients and outpatients with Parkinson's disease. METHODS: MA was continuously recorded with a wrist-worn activity monitor (actigraph) in 29 hospitalized PD patients without tremor or abnormal involuntary movements. In another series consisting of 8 outpatients, the response duration of CBG was measured by using averaged actigraphy. RESULTS: By averaging data gathered every 24 h over several days, it was possible to quantify the circadian patterns of akinesia. These cumulative evaluations of the patients' motor status determined 4 types of akinesia: (1) a wearing-off pattern seen in advanced efficacy stages, (2) stable response, (3) afternoon akinesia, and (4) morning akinesia. Following CBG therapy, the MA increased significantly throughout the daytime, i.e.: by 40% in the morning (8:00 a.m. to 12:00 noon), by 60% in the afternoon (12:00 noon to 6:00 p.m.), and by 60% in the next early morning (from time to get up until 8:00 a.m.). CONCLUSION: In averaged motor activity, the charting of cumulative evaluations of motor status revealed the long-acting efficacy of CBG in ameliorating existing motor fluctuations throughout the daytime and even promoting sleep benefit in the next morning. Averaged actigraphy is considered to be useful in the quantitative detection of drug responses to parkinsonian akinesia and its circadian variations. This enables titration of the lowest dose of drugs needed to alleviate akinesia.

Aged↗
PubMed2001

Regulation of calcitonin receptor by glucocorticoid in human osteoclast-like cells prepared in vitro using receptor activator of nuclear factor-kappaB ligand and macrophage colony-stimulating factor.

Using mouse osteoclast-like cells (OCs), we have shown that treatment with glucocorticoids (GCs) resulted in an increase in calcitonin (CT) binding by enhancing CT receptor (CTR) gene transcription. Additionally, treatment with GCs demonstrated increased sensitivity to CT. There is, however, scant information on the effects of GC or CTR regulation by GCs in human osteoclasts. In this study we examined CTR regulation by GCs and the effects of GCs and CT together in human OCs. OCs were prepared by treatment of peripheral blood mononuclear cells in vitro with soluble receptor activator of nuclear factor-kappaB ligand and macrophage colony-stimulating factor. Treatment of mature OCs with dexamethasone (Dex) resulted in a dose- and time-dependent increase in [(125)I]salmon CT (sCT) binding capacity. Treatment with Dex enhanced CTR messenger RNA (mRNA) expression, suggesting that CTR up-regulation is at least partly due to an increase in de novo CTR synthesis. Triamcinolone and prednisolone reproduced the Dex effect on [(125)I]sCT-specific binding and CTR mRNA expression, but 17beta-estradiol, progesterone, dehydroepiandrosterone, and aldosterone did not. A Scatchard plot analysis showed that Dex enhanced CTR number with a minimal change in the affinity to sCT. Autoradiographic studies using [(125)I]sCT showed that Dex enhanced the CTR density on individual multinuclear OCs. Up-regulation of [(125)I]sCT-specific binding and CTR mRNA expression was seen even in the presence of sCT, but the enhancement diminished subsequently at later times (36-48 h after sCT removal), which was consistent with our previous observation in mouse OCs. This suggests that GCs and CTs act on CTR expression differently, consistent with our previous work using mouse OCs, in which we found that GCs increased transcription of CTR gene expression, whereas CT reduced CTR mRNA stability. The results obtained in this study show that GC increased CTR expression and sensitivity to CT in cells of the human osteoclast lineage and provide the basis for understanding the beneficial effects of combination treatment with GCs and CTs in malignancy-associated hypercalcemia.

Acid Phosphatase↗
PubMed2001

Two new steroidal derivatives from the fruit body of Chlorophyllum molybdites.

Two new steroid derivatives, (22E,24R)-3alpha-ureido-ergosta-4,6,8(14),22-tetraene (1) and (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-triene-3beta-ol 3-O-beta-D-glucopyranoside (2) were isolated from the fruit bodies of Chlorophyllum molybdites (Agaricaceae). The structures were established by spectroscopic and chemical methods. These compounds exhibited cytotoxicity against Kato III cells.

Agaricales↗
PubMed2001

A benzofuran glycoside and an acetylenic acid from the fungus Laetiporus sulphureus var. miniatus.

A new benzofuran glycoside, masutakeside I (1) and a new C10 acetylenic acid, masutakic acid A (2) were isolated from the fruiting bodies of the fungus Laetiporus sulphureus var. miniatus. Their structures were established by spectroscopic and chemical methods. The known compounds 3-6 were also obtained and identified as egonol, demethoxyegonol, egonol glucoside and egonol gentiobioside. Some of these compounds exhibited cytotoxicity against Kato III cells.

Alkynes↗
PubMed2001

Protective effects of clostridium sordellii LT and HT toxoids against challenge with spores in guinea pigs.

The protective effects of Clostridium sordellii lethal toxin (LT) and hemorrhagic toxin (HT) toxoids against challenge with spores in guinea pigs were investigated. Purified LT and partially purified HT were obtained from the culture supernatant of C. sordellii strain 3703, and then were treated with formalin to make toxoids. LT. HT and combined LT and HT (LT/HT) toxoid vaccines were prepared by mixing each toxoid with an aluminum phosphate gel as adjuvant. Guinea pigs immunized twice with the respective toxoid vaccines were challenged with spores of strains 3703 or KZ1047. The latter strain does not produce HT. LT toxoid vaccine conferred protection against challenge with strain KZ1047, but not strain 3703, in guinea pigs. All guinea pigs immunized with HT toxoid vaccine died after challenge with spores of either strain. LT/HT toxoid vaccine gave complete protection against challenge with spores of strains 3703 and KZ1047 to guinea pigs. These results suggest that not only LT toxoid, but also HT toxoid, are essential protective antigens of C. sordellii.

Adjuvants, Immunologic↗
PubMed2001

Induction of autoimmune hypothyroidism and subsequent hyperthyroidism by TSH receptor antibodies following subacute thyroiditis: a case report.

A 45 year-old man had a typical episode of subacute thyroiditis with tender goiter, depressed radioiodine uptake (RAIU) and elevated erythrocyte sedimentation rate. The titer of TSH binding inhibitor immunoglobulin (TBII), which had been 8.6% at initial presentation, rose to 14.9% in 2 weeks. TBII consisted of high titers (94%) of TSH stimulation-blocking antibodies (TBAb) and negative thyroid stimulating antibodies (TSAb). About 2 months after the first visit, TBII titers had risen to 48.9% and were persistently elevated for 5 months with high TBAb activity. The patient developed hypothyroidism with a maximum serum TSH level of 54.5 microU/ml. TBII and TBAb titers then gradually decreased, and the patient spontaneously recovered from hypothyroidism. Eighteen months after the episode of subacute thyroiditis, he became hyperthyroid with elevated TSAb and negative TBAb values. Doppler ultrasonography showed increased blood flow in the thyroid, and RAIU at 24 h was 53%. He was treated with antithyroid drugs, and soon became euthyroid. This case indicates that subacute thyroiditis can induce thyroid autoimmunity, and that the character of TSH receptor antibodies (TSHRAb) in these patients can change thereby modifying their thyroid function.

Antithyroid Agents↗