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S Kato

Publications and source records attributed to S Kato.

At least 343 records · Page 19Linked to original sources

[Peroxisome proliferator-activated receptor(PPAR)--structure, function, tissue distribution, gene expression].

Peroxisome proliferator-activated receptors(PPARs, alpha, beta/delta, and gamma) are members of the nuclear receptor superfamily of ligand-activated transcription factors. PPAR has been shown to be regulated the expression of genes involved in lipid metabolism by various compounds such as fibrates, thiazolidinediones, prostaglandins, and fatty acids that is important in adipocyte differentiation and glucose homeostasis. PPARs form a heterodimer with the retinoid X receptor(RXR) and bind to specific DNA sequences located upstream of peroxisome proliferator responsive genes and interact with co-activators, including SRC-1 family, CBP/p300 or TRAP/DRIP complex by ligand dependent way. It is suggested that the selective interactions of PPAR with coactivators induced by PPAR's compounds specify the biological activities of the its compounds. Such differential combinations of transcription factors/coactivators are believed to activate only particular sets of target gene promoters.

Animals↗

Usefulness of hemodynamic evaluation in patients with major cerebral arterial occlusive disease before cardiac surgery.

Patients with ischemic heart disease are often complicated with cerebrovascular disease. The purpose of this study is to examine the usefulness of Xe-CT CBF study in patients with cerebral arterial occlusive disease before cardiac surgery with cardiopulmonary bypass. This study was carried out in 11 patients suffered from ischemic heart disease with cerebrovascular diseases. They had severe stenoses or occlusions of cerebral arteries. Cerebral hemodynamics was measured by Xe-CT. There were no ischemic complications in the brain or heart during the study. Hemispheric CBF in the occlusive side is lower than that in the non-occlusive side. Cerebral ischemic events occurred in one patient after the cardiac surgery. Xe-CT CBF study can be performed safely in patients with ischemic heart disease. The patients with low CBF and low cerebrovascular reserve, had a greater risk of cerebral complication after cardiac surgery with cardiopulmonary bypass.

Adult↗

The value of acetazolamide challenge test in the evaluation of acute stroke.

The acetazolamide (ACZ) challenge test provides a useful information about compromised hemodynamic state in chronic stroke. However, there is no consensus whether this test is of any value in the evaluation of acute ischemic stroke. The purpose of this study is to examine the value of ACZ challenge test in the management of acute ischemic stroke. Study 1: Nineteen patients with acute embolic stroke were subjected to the Xe CT with and without ACZ (17 mg/kg, i.v.) within 6 hours from the onset. The cases included 12 middle cerebral artery (MCA) occlusions and 7 internal carotid artery (ICA) occlusions. The baseline cerebral blood flow (CBF) values and cerebrovascular reserve (CVR) (% increase in CBF after ACZ) were analyzed in 53 affected regions of interest (ROI). The study indicated that the CBF threshold of subsequent permanent infarction was 15 ml/100 g/min and the ROI with negative CVR had a higher incidence of hemorrhagic infarction. Study 2: Xe-CT with and without ACZ was performed in 32 patients with acute occlusion of the main trunks of cerebral arteries within 6 hours after the onset. Occluded arteries were MCA in 20 patients, ICA in 7, both ICA and MCA in 4 and anterior cerebral artery (ACA) in one. The abnormal hemispheric CBF (< 20 ml/100 g/min) and CVR (< 10%) were correlated with the Glasgow outcome scales of the patients. The predictability of Good Recovery, Moderately Disabled, Severely Disabled, Vegetative Survival and Dead were 80%, 50%, 50%, 100% and 100% by CBF criteria, and 80%, 60%, 80%, 100% and 100% by CVR criteria, respectively. There was no significant increase in the predictability of final outcome of the patients by adding the CVR information of the acute stage. The ACZ challenge test has a potential value in the prediction of hemorrhagic transformation of the ischemic regions. It does not increase the predictability of the long-term outcome. We do not recommend performing ACZ challenge test on routine basis in the evaluation of acute ischemic stroke.

Acetazolamide↗

Effect of acute ethanol administration on the intestinal absorption of endotoxin in rats.

BACKGROUND: Endotoxin has been implicated in the pathogenesis and progression of alcoholic liver disease. Not only inactivation of reticuloendothelial function, which reduces clearance of endotoxin, but also an increase in absorption of endotoxin from the intestine may be involved in mechanisms of ethanol-induced endotoxemia. However, it is unclear how ethanol affects absorption of endotoxin from the intestine in vivo. METHODS: We gave 10 mg/kg of lipopolysaccharides to rats with water (group 1), 5% ethanol (group 2), or 20% ethanol (group 3) using an intubation tube to the stomach. Blood samples were collected and plasma endotoxin levels were measured. We used fluorescence spectrophotometer to examine permeability of the gut to macromolecules (fluorescein isothiocyanate-dextran; 4,000 Da [FD4] or 20,000 Da [FD20]). RESULTS: Plasma endotoxin levels were not different between group 1 (9 +/- 2 pg/ml) and group 2 (14 +/-3 pg/ml), whereas they significantly increased in group 3 with a peak at 60 min (87 +/- 35 pg/ml). Acute ethanol administration did not affect clearance of endotoxin in rats. Hemorrhagic erosions of the proximal small intestine with epithelial cell loss were observed in group 3 at 4 hr, but no significant histological change was observed at 30 min by light microscopy. Acute ethanol administration (20%) increased the permeability of the small intestine to FD4 and FD20 in 30 min when no hemorrhagic erosions of the proximal small intestine with epithelial cell loss were observed. CONCLUSIONS: Acute ethanol administration increases intestinal permeability before pathological changes are revealed by light microscopy. Acute ethanol ingestion, especially at high concentrations, facilitates the absorption of endotoxin from rats' small intestine via an increase in intestinal permeability, which may play an important role in endotoxemia observed in alcoholic liver injury.

Animals↗

Detection of the Na(+)-translocating NADH-quinone reductase in marine bacteria using a PCR technique.

To examine the distribution of the Na(+)-translocating NADH-quinone reductase (Na(+)-NQR) among marine bacteria, we developed a simple screening method for the detection of this enzyme. By reference to the homologous sequences of the Na(+)-NQR operons from Vibrio alginolyticus and Haemophilus influenzae, a pair of primers was designed for amplification of a part of the sixth ORF (nqr6) of the Na(+)-NQR operon. When PCR was performed using genomic DNA from 13 marine bacteria, a 0.9-kbp fragment corresponding to nqr6 was amplified in 10 strains. Although there were three PCR-negative strains phylogenetically, based on the sequence of the 16S rRNA, these were placed far from the PCR-positive strains. No product was observed in the case of nonmarine bacteria. The nucleotide and predicted amino acid sequences of nqr6 were highly conserved among the PCR-positive marine bacteria. A phylogenetic analysis of marine bacteria, based on nqr6 sequencing, was performed.

Amino Acid Sequence↗

Sex differences in proximal humeral outline shape: elliptical Fourier functions.

A method is presented for the numerical analysis of sex differences in size and shape of the proximal humeral outlines using elliptical Fourier functions (EFFs). A skeletal sample consisting of right and left humeri pairs of 69 individuals, 36 males and 33 females, was used. The proximal superior view in the plane of the proximo-distal axis of each humerus was photographed and then 54 boundary points were located on the two-dimensional outline tracings. These points were digitized and used to compute EFFs with 27 harmonics. From the EFFs, a set of expected points on the proximal humeral outline was generated using the centroid as an origin. Superimposition of the male and female outlines on this centroid provided a detailed picture of the relative sex differences in size and shape with respect to that center. The bounded area of the proximal humeral outline showed statistically significant sex differences. Additionally, statistical results of the amplitudes derived from the "area-standardized" EFFs and visual assessments of the mean outline plots indicated significant sex differences in shape of the proximal humeral outlines. Focusing on localized regional differences, the greater tubercle was located more postero-medially and the lesser tubercle was located more anteriorly in the males compared to the females. Sex determinations from the proximal humeri were also examined with discriminant functions based on the amplitudes, which represent shape characteristics of the outline, and the hounded area. Using a cross-validation method, predictions of the percentages of cases correctly classified with the discriminant functions were ranged from 92.8% to 95.7% for the right and left humeral data. These results suggest that differences in size and shape of the proximal humeral outlines may be better predictors of sex when compared with conventional measurements of the humerus.

Adult↗

Hepatic microvascular dysfunction in endotoxemic rats after acute ethanol administration.

BACKGROUND: A high concentration of ethanol is reported to cause hepatic microvascular dysfunction. However, little is known about the effect of ethanol on hepatic microcirculation in endotoxemic animals. The objective of this study was to determine whether endotoxemia enhances the hepatic microvascular dysfunction induced by acute ethanol administration. METHODS: Intravital videomicroscopy was used to monitor leukocyte recruitment, number of nonperfused sinusoids, and flow velocity of erythrocytes (RBC) labeled with fluorescein isothiocyanate (FITC) in the livers of male Wistar rats that were administered ethanol (20%, 3 g/kg; or 40%, 6 g/kg) from a gastric tube. Flow velocity of RBC in sinusoids was measured with an off-line velocimeter. Plasma tumor necrosis factor (TNF)-alpha levels were also measured. In some experiments, rats were injected with 2 mg/kg of lipopolysaccharides (LPS) intraperitoneally at 16 hr before the experiments, and the same protocol was performed. RESULTS: Although FITC-RBC velocity was initially increased by both 20% and 40% ethanol in control rats, it was reduced by only 40% ethanol at 60 min. In LPS-treated rats, the FITC-RBC velocity also was increased initially but was reduced at 60 and 30 min by 20% and 40% ethanol, respectively. Only 40% ethanol caused leukostasis in the pericentral region of control rats. In LPS-treated rats, however, leukostasis was noted in the midzonal and pericentral regions of liver after both 20% and 40% ethanol administration. Ethanol increased plasma TNF-alpha levels only in LPS-treated rats. CONCLUSIONS: These results suggest that LPS synergistically enhances ethanol-induced hepatic microvascular dysfunction and liver injury, especially in the midzonal region via coagulation, which may be mediated by TNF-alpha.

Animals↗

A case of normotensive scleroderma renal crisis after high-dose methylprednisolone treatment.

A 68-year-old male was admitted for interstitial pneumonia associated with scleroderma. High-dose methylprednisolone was administered for treatment of the pneumonitis. Two weeks later, anemia, thrombocytopenia and progressive increase in BUN, creatinine and LDH were observed. Although the blood pressure remained normotensive, renal biopsy showed thrombosis of the polar arterioles and glomerular capillaries. The affected interlobular artery included concentric intimal thickening and thrombosis in the lumen. Our findings suggested that the antecedent use of high-dose corticosteroids is involved in precipitating normotensive renal crisis. Corticosteroids should be used in low doses and with great caution in scleroderma patients.

Aged↗

Role of nitric oxide in endotoxin-induced hepatic microvascular dysfunction in rats chronically fed ethanol.

BACKGROUND: Nitric oxide (NO) appears to be involved in the pathogenesis of endotoxin-induced liver injury. However, little is known about how NO acts on the hepatic microcirculation, especially in alcohol-fed animals. We examined the roles of NO in endotoxin-induced hepatic microvascular dysfunction in control and ethanol-fed rats. METHODS: One lobe of the liver was observed with an intravital microscope. Flow velocity of fluorescein isothiocyanate-labeled erythrocytes in sinusoids was measured with an off-line velocimeter. Portal pressure and mean arterial pressure also were measured. RESULTS: After administration of endotoxin to control, the flow velocity decreased after 30 min. Portal pressure increased after 45 min. However, in ethanol-fed rats, both the flow velocity and portal pressure temporarily increased in the early phase. Thereafter, the flow velocity decreased and portal pressure increased. At 30 min after administration of the endotoxin, pretreatment with 10 mg/kg of an NO synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), enhanced the endotoxin-induced decrease in the velocity of erythrocytes in the midzonal region of both control and ethanol-fed rats. Although 0.5 mg/kg of L-NMMA enhanced the endotoxin-induced reduction of erythrocyte velocity in the midzonal region of ethanol-fed rats, L-NMMA enhanced the endotoxin-induced reduction of erythrocyte velocity in the pericentral region of control rats. At 60 min after the endotoxin administration, L-NMMA did not affect the endotoxin-induced decrease of erythrocyte velocity in either control or ethanol-fed rats. Although 10 mg/kg of L-NMMA increased mean arterial pressure both in control and ethanol-fed rats, 0.5 mg/kg of L-NMMA did not change mean arterial pressure in either control or ethanol-fed rats. CONCLUSIONS: These results suggest that NO is involved in endotoxin-induced hepatic microvascular dysfunction, which may contribute to the sequential liver injury, especially in alcohol-fed animals.

Animals↗

[Nuclear steroid hormone receptors as possible target molecule for endocrine disruptant].

Endocrine disruptant is supposed to act as a ligand to modulate a certain set of receptors. One class of the candidate receptors is the nuclear receptor superfamily. This family compromises nearly hundred members in human including steroid/thyroid hormones, vitamin A and D, other fat-soluble compounds nuclear receptors, and a subfamily of orphan receptors, whose ligands have not yet been identified. The nuclear receptors regulate transcription of target genes as ligand-inducible transcription factors. In this review, the functions of nuclear receptors are described in terms of transcriptional controls, and a possible target molecule for endocrine disruptants is discussed.

DNA↗

Amelioration of murine experimental colitis by inhibition of mucosal addressin cell adhesion molecule-1.

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is an adhesion molecule that mediates recruitment of lymphocytes into the gut mucosa. Attenuation of excessive expression of MAdCAM-1 in the inflamed mucosa could be useful for treatment of inflammatory bowel diseases. The aim of this study was to investigate whether anti-MAdCAM-1 antibody has a prophylactic effect on experimental colitis induced by dextran sulfate sodium (DSS). Colitis was induced by orally feeding BALB/c mice 5% DSS (mol. wt. 5000). Mice were sacrificed at intervals up to 21 days after administration to evaluate the changes over time in intestinal damage. The infiltrating lymphocytes and their subpopulations, and the expression of cell adhesion molecules were determined by immunohistochemistry. In another set of experiments, the attenuating effect of i.p.-injected anti-MAdCAM-1 antibody on colonic lesions was evaluated on day 14. Significant histological damage with shortening of crypts was observed on day 14 in colonic mucosa of DSS-treated mice. Before mucosal inflammation had become significant, expression of MAdCAM-1 was already increased in the microvessels of lamina propria on day 7. Significant infiltration of beta7-integrin-positive T and B cells in the mucosa was then noted on day 14. Administration of anti-MAdCAM-1 antibody significantly reduced colonic injury as well as the infiltration of beta7-integrin-positive lymphocytes in the colonic mucosa. This antibody also was effective when given 7 days after the start of DSS treatment. In the present study, we demonstrated that anti-MAdCAM-1 antibody significantly ameliorates DSS-induced colitis, suggesting that MAdCAM-1 may be useful for control of inflammatory bowel diseases.

Animals↗

[A clinical study of psychopathology in systemic lupus erythematosus].

Thirty patients (24 inpatients and 6 outpatients) with a clinical diagnosis of SLE were examined between September 1, 1998 and August 1, 1999 in the rheumatology clinic of Jichi Medical School Hospital. All of these patients fulfilled the 1982 revised criteria of the American Rheumatism Association for the classification of SLE and had some psychiatric manifestations (psychiatric SLE; P-SLE group). Mean patient age was 38.6 +/- 13.0, and there were 5 males and 25 females. When classified into 5 subgroups according to the most prominent symptoms, the distribution was as follows: consciousness disturbance group: 6 (20%), schizophrenia-like group: 5 (16.7%), mood disorder group: 7 (23.3%), neurosis-like group: 10 (33.3%), and convulsive disorder group: 2 (6.7%). Among all 37 psychiatric episodes, symptoms appeared in 37.8% of cases during the acute phase of SLE (during onset or recurrence) and in 62.9% during the chronic phase (during remission). The profile of the P-SLE group showed that the psychiatric symptoms of the SLE patients were milder and more chronic than those described in previous reports. To begin to comprehend the psychopathology of SLE, we put forward the concept of "Psychiatric basal state" and "psychiatric conjugated state". The former is considered a direct reflection of the acute-phase SLE process on mental condition. It is defined clinically as psychiatric symptoms that parallel the activity of SLE and respond well to steroid therapy. The latter include all other psychiatric problems in which one cannot rule out the effects of pharmacological, somatic, personality, and environmental effects on psychiatric symptoms. Only 3 patients in the P-SLE group fulfilled the criteria for the "psychiatric basal state". All three patients belonged to the consciousness disturbance group, whose clinical features were defined as slight clouding of consciousness, so-called "Amentia" in the sense of the German terminology. The clinical profile of this state is: 1. the patients are young (about 16 years old), 2. the onset of psychiatric symptoms is within 5 years after the onset of SLE, 3. confusion and disorientation are the most characteristic features, and 4. the clinical course of this state is almost 2 months. The experience structure of the "psychiatric basal state" consists of: 1. difficulty in selecting and holding a topic in cognition, 2. confusion and emotional instability as the basal mood, and 3. primitive and floating forms of delusions and hallucinations. Using this concept of the "psychiatric basal state" as a clue, we can hypothesize the continuity of diverse psychiatric symptoms in SLE. The "proper process of SLE (Harada)" has a disintegrating effect on the "ego" and it allows various psychopathological phenomena to emerge in the experience field. Against this background, additional factors, such as secondary organ damage, personality structure, and social environment, induce organization of the "psychiatric conjugated state".

Adolescent↗

[Nuclear receptor-mediated signaling pathway].

Nuclear receptors for steroid/thyroid hormones, vitamins A and D, and fat-soluble ligands form a gene superfamily of ligand-inducible transaction factors, which plays important roles in a wide spectrum of biological events by regulating the expression of a set of target genes. DNA-bound nuclear receptors control transcription in a ligand-binding dependent way in cooperation with a multiprotein complex containing RNA polymerase II and a series of auxillary factors, TFIIA, B, D, E, F and H. During the process of ligand-induced transactivation by nuclear receptors, nuclear cofactors interacting with AF-1 and AF-2 seem to be involved. Several transcriptional co-activators and co-repressors forming coactivator complexes have been recently identified, and their function is discussed.

Humans↗