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Biomedical subjects

M Sato

Publications and source records attributed to M Sato.

At least 451 records · Page 25Linked to original sources
PubMed2000

Frequency dependence of H2O2 generation from distilled water

The frequency dependence of H2O2 generation from H2O by a sonochemical reaction was detected experimentally. The results are in good agreement with previous experimental results, which indicate that in sonochemical reactions, frequencies higher than 90 kHz are more effective than frequencies of several tens of kilohertz. The phonon concept of acoustic waves makes it clear that energy depends on frequency, i.e. on the condition of equal phonon density; higher frequency means higher energy. The concentration and accumulation of acoustic energy will be performed through a bubble surface. From the analogy of photoelectric effects, the frequency dependence of the sonochemical reaction was discussed using the phonon concept.

Journal Article↗
PubMed2000

Visualization of human umbilical vein endothelial cells by acoustic microscopy.

The morphology and acoustic properties of the human umbilical vein endothelial cells (HUVECs) were evaluated using a scanning acoustic microscope system. HUVECs were cultured for 4 days and exposed to the endotoxin for 4 h. The frequency of the scanning acoustic microscope was variable between 100 and 210 MHz. By changing the measuring frequency, ultrasonic amplitude and phase were measured and the quantitative value of attenuation was calculated. Before and after endotoxin stimuli, HUVECs were observed by scanning acoustic microscopy and the attenuation was measured. The acoustic images were successfully obtained to identify the outer shape of the HUVEC and the location of the nucleus in the cell. The attenuation of the nucleus is higher than that of the cytoplasm. The attenuation of the cytoplasm was increased and became inhomogeneous after endotoxin exposure. This finding would be related to the change of F-actin filaments, which is the main component of the cytoskeleton. Scanning acoustic microscopy is useful for assessing the cellular viscoelastic properties since it can detect both the morphological and acoustic changes without contacting the cellular surface.

Acoustics↗
PubMed2000

Cisternal irrigation therapy with urokinase and ascorbic acid for prevention of vasospasm after aneurysmal subarachnoid hemorrhage. Outcome in 217 patients.

BACKGROUND: Cisternal irrigation therapy with urokinase and ascorbic acid was introduced to prevent symptomatic vasospasm after aneurysmal subarachnoid hemorrhage (SAH). To dissolve and wash out the subarachnoid clot, cisternal irrigation with urokinase is used. Ascorbic acid is added to degenerate oxy-hemoglobin, one of the strongest spasmogenic substances, into verdohemelike products, which are nonspasmogenic. The efficacy and safety of this therapy were evaluated. METHODS: This therapy was performed consecutively in 217 patients. The degree of SAH of the patients was classified as Fisher CT Group 3, and the highest CT number (Hounsfield number) exceeded 60 in the SAH, which suggested a significant risk for symptomatic vasospasm. All patients underwent surgery within 72 hours from the onset of SAH. After clipping the aneurysm, irrigation tubes were placed in the Sylvian fissure (inlet) unilaterally or bilaterally and in the prepontine or chiasmal cistern (outlet). Lactated Ringer's solution with urokinase (120 IU/mL) and ascorbic acid (4 mg/mL) was infused at a rate of 30 mL/hour/side for approximately 10 days. RESULTS: Of the 217 patients studied, symptomatic vasospasm was observed in 6 cases (2.8%), and two of these six cases (0.9%) demonstrated sequelae. The average total blood volume calculated from the drainage fluid was approximately 114 mL. Analysis of the absorption spectrum of the drainage fluid revealed disappearance of the oxy-hemoglobin-specific 576-nm peak. Complications occurred in eight patients during irrigation therapy; two patients experienced seizures, two patients developed meningitis, and four patients had an intracranial hemorrhage. However, all of these patients recovered without neurological deficits. CONCLUSIONS: These results suggest that cisternal irrigation therapy with urokinase and ascorbic acid is effective in preventing symptomatic vasospasm after aneurysmal SAH.

Adult↗
PubMed2000

Induction of Th1-type cytokines by lipoteichoic acid-related preparation isolated from OK-432, a penicillin-killed streptococcal agent.

We have isolated the lipoteichoic acid (LTA)-related molecule (OK-PSA) from OK-432, a streptococcal preparation, by an affinity chromatography on CNBr-activated Sepharose 4B-bound TS-2 monoclonal antibody (mAb) that neutralizes interferon (IFN)-gamma-inducing activity of OK-432. In in vitro experiments using human peripheral blood mononuclear cells (PBMC), OK-PSA induced IFN-gamma, interleukin (IL)-2, IL-12, IL-18, tumor necrosis factor (TNF)-alpha and TNF-beta that are generally called "Th1-type cytokines" both in protein and in mRNA levels. Furthermore, the neutralizing test using cytokine-specific antibodies demonstrated that IL-18 plays a most significant role for IFN-gamma- and killer cell-inducing ability of OK-PSA among the other cytokines tested. These findings clearly indicated that OK-PSA, an LTA-related molecule, is a main effective component of OK-432, and is a potent inducer of Th1-type cytokines by T cell and natural killer (NK) cell activation mediated by monocytes-derived IL-18, and that it may be a useful immunotherapeutic agent for the patients with malignancies better than original OK-432.

Animals↗
PubMed2000

Purification and characterization of cytokine-inducing protein of seed extract from Aeginetia indica L., a parasitic plant.

We have isolated 55 kDa protein from the seed extract of Aeginetia indica L. (AIL), a parasitic plant, by an affinity chromatography on N-hydroxysuccinimide (NHS)-activated Sepharose High Performance column bound F3 monoclonal antibody which neutralizes cytokine-inducing and antitumor effect of AIL. In in vitro model using human peripheral blood mononuclear cells (PBMC), the 55 kDa protein (AILb-A) induced multiple cytokines, such as IFN-gamma, tumor necrosis factor (TNF)-alpha, granulocyte macrophage-colony stimulating factor (GM-CSF), IL-2, IL-6, IL-10, IL-12 and IL-18, and also accelerated killer cell activities of PBMC. When compared with a commonly used immunotherapeutic agent OK-432, AILb-A induced Th1 cytokines are greater than OK-432. Of the Th2 cytokines, the amounts of IL-6 and IL-10 induced by AILb-A were lower than those by OK-432. No significant induction of IL-4 and IL-13 was observed in AILb-A-stimulated PBMC. TNF family including TNF-alpha, TNF-beta, Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL) were suggested to be important for AILb-A-induced killing activity of PBMC by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Furthermore, the neutralizing test using cytokine-specific antibodies demonstrated that IL-18 plays a most significant role for IFN-gamma- and killer cell-inducing ability of AILb-A among the cytokines tested. These findings clearly indicated that AILb-A, a 55 kDa protein of AIL, is a potent Th1 cytokine inducer and may be a useful immunotherapeutic agent for the patients with malignancies.

Adjuvants, Immunologic↗
PubMed2000

Psychiatric disorders in juvenile patients with insulin-dependent diabetes mellitus.

The relationships of psychiatric characteristics to metabolic control and psychosocial functioning were examined in a group of 16 patients with insulin-dependent diabetes mellitus (IDDM) (mean age: 14.3+/-5.1 years, mean duration of follow-up: 5.0+/-2.3 years) and psychiatric disorders. The comparison is also made to 69 IDDM controls (mean age: 17.0+/-6.7 years) without psychiatric disorders. Metabolic control was evaluated in terms of glycosylated hemoglobin (HbA1c). Psychosocial functioning at both psychiatric treatment entry and discharge was assessed using the global assessment of functioning (GAF) scale. Subjects were divided into three subgroups - Somatoform Type (25%), Behavioral Type (50%) or Psychotic Type (25%) - according to the Diagnostic and Statistical Manual of Mental Disorders, third edition revised (DSM-III-R), based on semi-structured interviews. Four patients (25%) were diagnosed as having schizophrenia or schizoaffective disorder (Psychotic Type), which is rather rare. The mean HbA1c level in the Behavioral Type patients was significantly higher than in the other subgroups (P<0. 01). After psychiatric treatment a significant difference (P<0.0001) in the GAF Scale was observed in the Psychotic Type compared with the other subgroups. We conclude that the Behavioral Type is associated with poor metabolic control and that for the Psychotic Type, improved psychosocial functioning can be achieved through psychiatric treatment.

Adaptation, Psychological↗
PubMed2000

High plasma cardiac natriuretic peptides associated with enhanced cyclic guanosine monophosphate production in preascitic cirrhosis.

BACKGROUND/AIMS: The initial abnormalities of renal sodium handling in cirrhosis remain unclear. The aim of this study was to characterize sodium metabolism in preascitic cirrhosis. METHODS: Ten patients with preascitic cirrhosis and ten controls were studied. All subjects ate a diet providing 120 mmol sodium during an equilibration period lasting 5 days and the study day. On the study day, after remaining in bed, plasma levels of atrial natriuretic peptide, brain natriuretic peptide, renin activity, aldosterone, noradrenaline, and cyclic guanosine monophosphate were measured at 7 am. Thereafter, they were instructed to maintain an upright posture until dinner and the measurements were repeated at 9 am and 6 pm. After having dinner, all subjects were asked to remain in bed and the measurements were repeated at 11 pm. To measure renal sodium and cyclic guanosine monophosphate excretion, 24-h urine collections were performed, starting from 7 pm on the day before the experimental day. RESULTS: Plasma levels of atrial natriuretic peptide, brain natriuretic peptide and cyclic guanosine monophosphate in patients with preascitic cirrhosis were significantly elevated compared with those in controls at every sampling time (p=0.03 or less, p= 0.04 or less, and p=0.01 or less). In contrast, plasma renin activities at every sampling time were significantly lower in patients than in controls (p= 0.04 or less). Plasma aldosterone and noradrenaline levels were not significantly different at every sampling time in the two groups. No significant differences in daily renal sodium excretion were found. However, urinary cyclic guanosine monophosphate excretion was significantly higher in patients than in controls (p<0.01). CONCLUSIONS: The initial abnormalities of sodium metabolism in cirrhosis might be characterized by blunted renal responsiveness to natriuretic peptides. The results of the study also provide indirect evidence that the impairment is mainly located at postreceptor levels of signal transduction pathway to the peptides, if the activation of antinatriuretic factors other than renin-angiotensin or sympathoadrenergic systems does not play a role.

Adult↗
PubMed2000

Inhibitory effects of tea extracts on the mutagenicity of 1-methyl-1, 2,3,4-tetrahydro-beta-carboline-3-carboxylic acid on treatment with nitrite in the presence of ethanol.

It has been shown that the mutagenicity of 1-methyl-1,2,3, 4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), a major mutagen precursor in soy sauce on treatment with nitrite and ethanol, was strongly decreased by the addition of hot water extracts of green, black and oolong teas in the reaction mixture when it was treated with 50mM nitrite at pH3.0, 37 degrees C for 60min in the presence of 7.5% ethanol. The mutagenicity-decreasing activity of the teas was scarcely decreased by washing the teas with chloroform and benzene and was partly decreased by butanol and ethyl acetate. Typical polyphenols such as catechins were shown to have the antimutagenicity dose dependently. The antimutagenicity and the reducing power of tea extracts gave a positive good correlation. The results suggest that the mutagenicity of MTCCA on treatment with nitrite in the presence of ethanol may be decreased by the mixed fractions of lyophilic components such as polyphenols, which have high reducing power such as catechins and the other compounds which have little reducing power including the derivatives of the catechins and so on. Although the antimutagenicity of teas and catechins was also considerably effective when they were added after the nitrosation, that of black tea and some catechins was less effective.

Carbolines↗
PubMed2000

New concept of information resolution in scanning electron microscope images

As a new means to evaluate SEM images from the viewpoint of image information, we have proposed information resolution, Rinf, defined as a spatial length per bit in information-passing capacity (IPC). The IPC densities (per basic area) were carried out by both taking into account the signal-to-noise ratio of the statistical mean power densities and applying a previously reported fitting functions to an optical system with an arbitrary size of aberration, diffraction (including lambda = 0), and source. Here, the nu-independent specimen contrast of tau(s)(nu)= 1 [used in Eq. (9)] is assumed. General characteristics on Rinf are typically plotted as a curve of log (Rinf/R(inf, ideal)) vs. log T, where T is (Bm2 + Cm4)(1/2), Bm and Cm are the modified spherical and chromatic aberrations, respectively. The subscript "ideal" represents an aberration-free optical system. The values of Rinf [calculated by Eq. (11)] are compared to those of the conventional beam size d [calculated by Eq. (1)] and the previously reported modified resolution Res [calculated by Eq. (7)]. It was found that R(inf, min) value is 0.3-0.9 times as small as the d(min) value and its corresponding beam semi-angle alpha(inf, min) is 1.2-1.8 times as large as the alpha(conv, min) value (depending on S/N).

Journal Article↗
PubMed2000

Suppression-burst patterns in intractable epilepsy with focal cortical dysplasia.

We report on a patient with early-onset spasms in series and partial seizures associated with focal cortical dysplasia whose EEGs showed suppression-burst patterns during early infancy. These electroclinical characteristics suggested a diagnosis of Ohtahara syndrome, but the EEG findings were atypical because of the lack of suppression-burst patterns during wakefulness. In addition, the patient did not have severe psychomotor retardation. With high-dose pyridoxal phosphate therapy, seizures were suppressed and suppression-burst patterns disappeared at 2 months of age. Focal motor seizures recurred later and they often evolved into epilepsia partialis continua. Patients with early-onset intractable seizures associated with suppression-burst patterns on EEGs have several different etiologies, and these patients should be categorized according to their etiology in addition to their syndromic diagnosis.

Cerebral Cortex↗
PubMed2000

Clinical aspects of hyperparathyroidism in Japanese multiple endocrine neoplasia type 1.

We describe here the clinical aspects of hyperparathyroidism (HP) in Japanese multiple endocrine neoplasia type 1 (MEN 1). The total number of MEN 1 patients was 37, and they originated from ten unrelated Japanese families. Nine of the ten families were proven to have heterozygous germline mutations of the MEN 1 gene. The incidence of HP, pituitary tumors, and pancreatic tumors in 37 MEN 1 patients was 91.9%, 32.4%, and 45.9%, respectively. The age-related penetrances of HP were 50%, 79%, 84%, by 20, 30, and 40 years of age, respectively. Of these MEN 1 patients, we used 28 individuals, diagnosed with HP at our hospitals, to study the clinical aspects of MEN 1-associated HP. The mean age was 40 years, and the mean was much lower in the sporadic (non-MEN 1) HP patients. The mean levels of calcium, phosphate, and intact PTH were 10.8 mg/dL, 2.3 mg/dL, and 178.0 pg/mL, respectively, and these were not different from those of sporadic HP patients. The levels of intact PTH were positively correlated with age, suggesting that HP may be progressive with time in MEN 1. The percentage of symptomatic HP was 36% in MEN 1, whereas it was 55% in sporadic HP patients. Although histopathological findings revealed that all four parathyroid glands were involved in hyperplasia, imaging studies showed an enlargement of only the single parathyroid gland in most patients. The combination of total parathyroidectomy and autoplantation succeeding in improving HP in MEN 1.

Adult↗
PubMed2000

Absence of somatic RET gene mutation in sporadic parathyroid tumors and hyperplasia secondary to uremia, and absence of somatic Men1 gene mutation in MEN2A-associated hyperplasia.

Germline mutations of the MEN1 gene are found in more than 85% of multiple endocrine neoplasia type 1 (MEN 1) patients, and germline mutations of the RET gene are found in more than 95% of multiple endocrine neoplasia type 2 (MEN2) patients. Parathyroid hyperplasia is seen in more than 90% of MEN 1 and about 15% of MEN2A patients. To date, somatic MEN1 mutations are reported in about 20% of sporadic parathyroid tumors. To elucidate the genetic basis of parathyroid tumor development, we examined somatic RET gene mutations in sporadic parathyroid tumors and hyperplasia secondary to uremia, and somatic MEN1 gene mutations in parathyroid hyperplasia from MEN2A patients. A total of 145 parathyroid tumors comprising 129 sporadic parathyroid tumors, 14 hyperplastic lesions secondary to uremia, and two hyperplastic lesions from MEN2A patients were examined. DNA was extracted from fresh frozen parathyroid tissue. Exons 2-10 of the MEN1 gene and exons 10 and 11 of the RET gene were sequenced. No somatic RET gene mutations were found in the 129 sporadic parathyroid tumors or 14 parathyroid hyperplastic lesions secondary to uremia. No somatic MEN1 gene mutations were found in the two parathyroid hyperplasia from MEN2A patients. These data suggest that RET gene mutation may not be involved in the development of sporadic parathyroid tumors and hyperplasia secondary to uremia and that MEN1 gene mutation may not be or is rarely associated with development of parathyroid hyperplasia in MEN2A patients.

Aged↗
PubMed2000

Involvement of pannier and u-shaped in regulation of decapentaplegic-dependent wingless expression in developing Drosophila notum.

In developing Drosophila notum, wingless expression is regulated by Decapentaplegic signaling positively and negatively so that only notal cells receiving optimal levels of Decapentaplegic signals express wingless (Sato et al., 1999b. Development 126, 1457-1466). Here, we show evidence that this Decapentaplegic-dependent regulation of notal wingless expression includes plural mechanisms, involving pannier and u-shaped. In the medial notum, Pannier and U-shaped form a complex (Haenlin et al., 1997. Genes Dev. 11, 3096-3108). The expression of pannier and u-shaped is positively regulated by Decapentaplegic signals emanating from the dorsal-most region. The Pannier/U-shaped complex serves as a repressor and a transcriptional activator, respectively, for wingless and u-shaped expression. In the more lateral region, wingless expression is up-regulated by U-shaped-unbound Pannier. wingless expression is also weakly regulated by its own signaling.

Animals↗
PubMed2000

Ibotenic acid-induced lesions of the medial septum increase hippocampal membrane associated protein kinase c activity and reduce acetylcholine synthesis: prevention by a phosphatidylcholine/vitamin B12 diet.

Ibotenic acid infusion into the medial septum (MS) results in biochemical alterations in the hippocampus. The biochemical events involved in this neuronal lesion are poorly understood. We investigated the effect of a purified diet supplemented with egg phosphatidylcholine (PC) and vitamin B(12) on ibotenic acid-medicated biochemical changes in the rat hippocampus and crude synaptosomal membranes. Male Wistar rats with this MS lesion were fed a purified diet (control diet) or a purified diet supplemented with 5.7 g PC and 125 microg vitamin B(12) per 100 g (experimental diet) for 18 days. Sham-operated rats were fed the control diet. Compared with the sham-operated rats, MS-lesioned rats fed the control diet showed increased activity of membrane-bound protein kinase C (PKC), decreased activity of choline acetyltransferase, and decreased concentrations of acetylcholine in the hippocampus. The ratio of cholesterol to phospholipid in the crude synaptic membrane was lower in the lesioned rats than in the sham-operated rats, but this was not accompanied by any alteration in membrane lipid fluidity. MS-lesioned rats fed the experimental diet showed lowered PKC activity and elevated acetylcholine concentrations than did rats fed the control diet, but there were no significant effects on choline acetyltransferase activity and the lipid ratio. The ibotenic acid-mediated elevation of PKC activity was observed as early as 2 days postinjury in the control diet-fed rats but not in the experimental diet-fed rats. We propose that ibotenic acid mediates pathophysiologic actions through the activation of PKC and that PC combined with vitamin B(12) ameliorates the second messenger-mediated injury.

Journal Article↗
PubMed2000

Distinct and essential roles of transcription factors IRF-3 and IRF-7 in response to viruses for IFN-alpha/beta gene induction.

Induction of the interferon (IFN)-alpha/beta gene transcription in virus-infected cells is an event central to innate immunity. Mice lacking the transcription factor IRF-3 are more vulnerable to virus infection. In embryonic fibroblasts, virus-induced IFN-alpha/beta gene expression levels are reduced and the spectrum of the IFN-alpha mRNA subspecies altered. Furthermore, cells additionally defective in IRF-7 expression totally fail to induce these genes in response to infections by any of the virus types tested. In these cells, a normal profile of IFN-alpha/beta mRNA induction can be achieved by coexpressing both IRF-3 and IRF-7. These results demonstrate the essential and distinct roles of thetwo factors, which together ensure the transcriptional efficiency and diversity of IFN-alpha/beta genes for the antiviral response.

Animals↗
PubMed2000

Detection of plasmalogen from plasma low density lipoprotein and high density lipoprotein in carp, Cyprinus carpio, and rainbow trout, Oncorhynchus mykiss.

The study revealed the presence of plasmalogens in the low density lipoprotein (LDL) and high density lipoprotein (HDL) of the fish. The composition of the plasmalogen in the carp plasma LDL phospholipids was 0.94 and 0.23% in the HDL; the LDL phospholipids in the rainbow trout were 0.44% and the HDL was 0.18%. Aldehydes from the plasmalogen were derivatized with dansylhydrazides and separated by high performance liquid chromatography (HPLC). Their presence was detected using a fluorescence detector. Hexadecanal (C16: 0), octadecanal (C18: 0) and octadecenal (C18: 1) were determined to be the major components in the carp and rainbow trout.

Animals↗
PubMed2000

Genetically high susceptibility to oral squamous cell carcinoma in terms of combined genotyping of CYP1A1 and GSTM1 genes.

An association of oral squamous cell carcinoma (SCC) susceptibility with an MspI restriction site polymorphism of the CYP1A1 gene and GSTM1 polymorphism were reported in our previous study (Sato M, Sato T, Izumo T, Amagasa T. Genetic polymorphism of drug-metabolizing enzymes and susceptiblility to oral cancer. Carcinogenesis 1999;20:1927-31). We report here that genetic risk for oral SCC was associated with another isoleucine-valine (Ile-Val) polymorphism, which resulted in an Ile-Val amino acid replacement in the heme-binding region of CYP1A1, and combined genotyping of CYP1A1 and GSTM1 genes in relation to the cumulative cigarette-smoking dose. The genetic polymorphisms of CYP1A1 and GSTM1 genes in oral cancer susceptibility were assessed by examining polymorphic prevalences in 142 oral SCC patients and 142 healthy controls who were individually matched to the patients with respect to sex and age (+/-1 year). Individuals with a combined genotype of Val/Val and GSTM1(-) were at an increased risk for oral SCC compared with other combined genotypes, in particular, at a low dose level of cigarette smoking.

Carcinoma, Squamous Cell↗