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Biomedical subjects

S Okada

Publications and source records attributed to S Okada.

At least 271 records · Page 15Linked to original sources
PubMed1999

Effects of thiamine and clenbuterol on body composition, plasma metabolites and hepatic oxygen consumption in broiler chicks.

1. We examined the effects of thiamine-hydrochloride (10 mg/kg body weight) and a beta-agonist, clenbuterol (50 microg/kg body weight), on plasma metabolites and hepatic oxygen consumption in female broiler chicks. 2. Clenbuterol, thiamine or both, dissolved in saline, were injected into thigh muscle on 2, 4 and 6 d of age. At 7 d of age blood samples in each treatment group were obtained and breast muscle and liver were weighed; liver slices were used for measurement of oxygen consumption. 3. Body weight gain was reduced by clenbuterol. Thiamine increased breast muscle weight as a proportion of body weight regardless of clenbuterol dose. Clenbuterol increased relative liver weight markedly, especially when chicks received thiamine also. 4. Clenbuterol increased plasma free fatty acid concentration in chicks treated with thiamine. Thiamine decreased plasma triglyceride regardless of clenbuterol dose. Plasma glucose concentration was decreased by both thiamine and clenbuterol. 5. The absolute rate of oxygen consumption in liver slices was greater in the thiamine-treated chicks; clenbuterol did not affect hepatic oxygen consumption. 6. These findings suggest that thiamine-induced energy expenditure results not only from thermogenesis in the liver, but also from increasing energy utilisation for muscle hypertrophy and this vitamin supplementation facilitates the lipolytic effects of the beta-agonist.

Adrenergic beta-Agonists↗
PubMed1999

Oxygen concentration regulates NO-dependent relaxation of aortic smooth muscles.

Nitric oxide (NO) functions as an endothelium-derived relaxation factor and regulates vascular resistance. Recent studies in this laboratory(Arch.Biochem.Biophys.323, 27-32, 1995) revealed that the lifetime of NO significantly increased at physiologically low levels of oxygen concentrations and, hence, this gaseous radical strongly inhibited mitochondrial electron transport for a fairly long duration at low oxygen concentrations. The present work describes the effect of oxygen concentration on NO-induced relaxation and guanylate cyclase (GC) activity of endothelium-denuded aorta of the rat. Both NO and 2,2 '-(hydroxynitrosohydrazono)bis-ethanamine (NOC18), an NO donor, induced the relaxation of endothelium-denuded helical segments of rat aorta which were contracted by norepinephrine. NO-dependent relaxation of arterial specimens was enhanced by lowering oxygen concentration in the medium with concomitant increase in their cGMP levels. Anoxia induced the relaxation of the aorta by some NO-enhanceable and methylene blue-insensitive mechanism. These results suggested that local concentrations of oxygen might play important roles in the regulation of NO-dependent GC activity and vascular tonus of resistance arteries.

Animals↗
PubMed1999

Rapid down-regulation of CD63 transcription by progesterone in human endometrial stromal cells.

Differentiation of endometrial stromal cells (decidualization) plays a crucial role in embryo implantation and maintenance of pregnancy. While progesterone is a key factor in regulating endometrial cell decidualization, the molecular mechanisms remain unclear. In the present study, we investigated the effect of gene transcription in human endometrial stromal cells (ESC) by progesterone, oestrogen or vehicle using the polymerase chain reaction-based differential display methodology. A transcript which is down-regulated by progesterone, but not by vehicle and oestrogen, was identified from a differential display band and the progesterone sensitivity of its expression was verified in Northern blot analysis. The level of the gene expression in progesterone-treated ESC was approximately 60% of that in the vehicle- and oestrogen-treated ESC. This cDNA was revealed to be human CD63 antigen, a recently identified member of the transmembrane 4 superfamily. The inhibitory effect of progesterone is observed within 30 min after hormone treatment. In human endometrium, CD63 mRNA levels were significantly decreased (P < 0.05) during the secretory phase compared with levels during the proliferative phase. This down-regulation of CD63 in vivo elevated levels of progesterone in the secretory phase. These results suggest that CD63 transcription is down-regulated by progesterone in human endometrium.

Adult↗
PubMed1999

Two mRNA species encoding calcium-dependent protein kinases are differentially expressed in sexual organs of Marchantia polymorpha through alternative splicing.

In plants, calcium-dependent calmodulin-independent protein kinases (CDPKs) are the predominant calcium-regulated protein kinases and their genes are encoded by a multigene family. A CDPK gene was cloned from a liverwort, Marchantia polymorpha, which showed a high level of sequence similarities to other higher plant CDPK genes. The liverwort CDPK gene consisted of 9 exons and 8 introns. The 6th and 7th exons (Exon 6A and Exon 6B) were almost identical except for 4-amino acid substitutions, both of which coded for EF-hands in the calcium-binding domain. RT-PCR analysis revealed that two species of mature mRNA containing either Exon 6A or Exon 6B were generated from a single CDPK gene by mutually exclusive alternative splicing. Both histidine-tagged fusion proteins derived from cDNAs containing either Exon 6A or Exon 6B exhibited calcium-dependent protein kinase activity in vitro. Preferential accumulation of the mature mRNA with Exon 6A detected in male sexual organ implies possible sexual control of the ratio between the two CDPK isozymes through alternative splicing. Functions and evolution of CDPKs are discussed based on the structure and expression of the liverwort CDPK gene.

Alternative Splicing↗
PubMed1999

An apoptotic depletion of oligodendrocytes in the twitcher, a murine model of globoid cell leukodystrophy.

Morphological alterations of oligodendrocytes (OLs) leading to their depletion were studied in the genetic demyelinating mutant, twitcher, a murine model of globoid cell leukodystrophy (GLD). With pi-glutathione-S-transferase immunostaining, OLs with multiple varicose processes were recognized in the early stages and adjacent areas of demyelination and then the OLs cytoplasm as well as the processes became shrunken with progression of the disease. These shrunken OLs were labeled by the TUNEL method, indicative of apoptotic cell death. The ultrastructural features of apoptotic cells were noted in these OLs and DNA laddering was noted in the twitcher brain in advanced stages. This is the first report describing the gradual depletion of OLs by apoptosis in genetic demyelination.

Animals↗
PubMed1999

A Japanese case of dengue fever with lymphocytic vasculitis: diagnosis by polymerase chain reaction.

A 37-year-old Japanese male was admitted to Nagasaki University Hospital with abrupt onset of biphasic fever, general malaise and myalgia 9 days after coming back to Japan from Manila. He developed a rubella like erythematous rash 3 days after admission and purpuric eruption one week after admission. A biopsied specimen from the purpura revealed lymphocytic vasculitis with T cell dominance and without immunoglobulin or complement deposition around the blood vessels. RT-PCR analysis on peripheral blood mononuclear cells using dengue virus specific primers confirmed the diagnosis of type 3 dengue fever. PCR analysis using virus specific primers is a rapid and valuable method for making a correct diagnosis of dengue fever.

Adult↗
PubMed1999

Ictal video-EEG recording of three partial seizures in a patient with the benign infantile convulsions associated with mild gastroenteritis.

PURPOSE: In infants, benign convulsions can be triggered by febrile illness or mild diarrhea such as Rotavirus gastroenteritis. The triggering mechanism of these convulsions is still unknown. In spite of several reports concerning clinical features, the ictal EEG recordings were rarely analyzed by a video-EEG monitoring system. To reveal a clue for the triggering mechanism of these convulsions, we analyzed the correlation of clinical manifestations and the EEG discharges during the ictal events and compared with previous reports. METHODS: The ictal EEG of a cluster of three afebrile convulsions associated with mild gastroenteritis was recorded by an EEG closed-circuit TV (EEG-CCTV) monitoring system in a 6-month-old healthy female infant. RESULTS: All seizures began as complex partial seizures (CPSs), which exhibited a motionless stare with or without leftward deviation of both eyes, and evolved to secondarily generalized tonic-clonic seizures (SGTCSs) for approximately 90 s. Each of three ictal discharges began from the right occipital, right centroparietotemporal, and left occipital regions, respectively. CONCLUSIONS: Although initiating sites of ictal discharges of benign infantile convulsions associated with mild gastroenteritis (BICE) were previously reported to be variable among patients, these results indicated that those differ among seizures even in a same infant.

Cerebral Cortex↗
PubMed1999

Diagnosis of pancreatic cancer by detecting telomerase activity in pancreatic juice: comparison with K-ras mutations.

OBJECTIVE: Telomerase activity is reported to be specific and very frequent in human malignancy. K-ras mutations are also very frequently detected in pancreatic cancer, but their specificity for pancreatic cancer is controversial. We examined the telomerase activity and K-ras mutations in pancreatic juice from patients with pancreatic disease. METHODS: Pancreatic juice was obtained endoscopically at endoscopic retrograde pancreatography from 10 patients with pancreatic cancer, three with chronic pancreatitis, and three with a normal pancreas. The telomerase activity in pancreatic juice was assayed by telomeric repeat amplification protocol. K-ras mutations in exon 1 codon 12 were examined by the two-step polymerase chain reaction combined with restriction enzyme digestion, followed by single-strand conformation polymorphism analysis and direct sequencing. RESULTS: Telomerase activity of >5.0 was detected in eight of 10 (80%) subjects with pancreatic cancer, but in none with chronic pancreatitis or normal pancreas. K-ras mutations were detected not only in eight of 10 (80%) subjects with pancreatic cancer but also in two of three with chronic pancreatitis and in one of three with a normal pancreas. CONCLUSIONS: It was shown that the detection of telomerase activity in pancreatic juice is a more useful diagnostic tool for pancreatic cancer than that of K-ras mutations.

Aged↗
PubMed1999

Interrelations of clinicopathological variables, local immune response and prognosis in esophageal squamous cell carcinoma.

The purpose of this study was to investigate the relationship between the local immune response, clinicopathological variables and prognosis in esophageal squamous cell carcinoma (SCC). A total of 377 cases of esophageal SCC without preoperative radiotherapy, chemotherapy or immunotherapy were studied. Corrected 5-year survival for pronounced, moderate and sparse immunocyte infiltration was 66%, 43% and 24%, respectively. In multivariate survival analysis, the immunocyte infiltration was an independent prognostic factor for survival (p<0.001). A correlation was found between density of T-cell and macrophage infiltration, depth of tumor invasion and lymph node metastasis using immunohistochemical analysis of the expression of T-cell, B-cell and macrophage markers. The results indicate that the local immunocyte infiltration is a manifestation of the host defense against cancer. It is therefore reasonable to infer that the local immunocyte infiltration in and around the cancer stroma is an important factor in predicting the prognosis of patients with esophageal SCC.

Adult↗
PubMed1999

Characteristics of two forms of alpha-amylases and structural implication.

Complete (Ba-L) and truncated (Ba-S) forms of alpha-amylases from Bacillus subtilis X-23 were purified, and the amino- and carboxyl-terminal amino acid sequences of Ba-L and Ba-S were determined. The amino acid sequence deduced from the nucleotide sequence of the alpha-amylase gene indicated that Ba-S was produced from Ba-L by truncation of the 186 amino acid residues at the carboxyl-terminal region. The results of genomic Southern analysis and Western analysis suggested that the two enzymes originated from the same alpha-amylase gene and that truncation of Ba-L to Ba-S occurred during the cultivation of B. subtilis X-23 cells. Although the primary structure of Ba-S was approximately 28% shorter than that of Ba-L, the two enzyme forms had the same enzymatic characteristics (molar catalytic activity, amylolytic pattern, transglycosylation ability, effect of pH on stability and activity, optimum temperature, and raw starch-binding ability), except that the thermal stability of Ba-S was higher than that of Ba-L. An analysis of the secondary structure as well as the predicted three-dimensional structure of Ba-S showed that Ba-S retained all of the necessary domains (domains A, B, and C) which were most likely to be required for functionality as alpha-amylase.

Amino Acid Sequence↗
PubMed1999

Thermus aquaticus ATCC 33923 amylomaltase gene cloning and expression and enzyme characterization: production of cycloamylose.

The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of the Escherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75 degrees C in a 10-min reaction with maltotriose and was stable at temperatures up to 85 degrees C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic alpha-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coli amylomaltase and the plant D-enzyme.

Amylose↗
PubMed1999

Decreased regional cerebral metabolic rate for glucose in systemic lupus erythematosus patients with psychiatric symptoms.

To determine brain functional abnormality in systemic lupus erythematosus (SLE) patients with psychiatric symptoms, we evaluated 12 active SLE patients with or without psychiatric symptoms by means of [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (PET), magnetic resonance imaging and neuropsychological testing. Patients with psychiatric symptoms showed significantly poorer performance in tests which subserved attentional function. The PET study revealed that the psychiatric patients had significantly decreased regional cerebral metabolic rates for glucose in the prefrontal, inferior parietal and anterior cingulate regions. Prefrontal, inferior parietal and anterior cingulate dysfunction may be related to attentional deficits that are involved in various psychiatric symptoms in SLE. PET is an invaluable tool to reveal such brain functional abnormality seen in SLE patients with psychiatric symptoms.

Adolescent↗
PubMed1999

Interstitial deletion of 14q, 46, XY, del (14) (q24.3q32.1) associated with status nonepileptic myoclonia and delayed myelination.

A Japanese boy with interstitial deletion of the long arm of chromosome 14, including band 14q31, is described. The characteristic dysmorphic facial features, such as dolichocephaly, bushy eyebrows, horizontal narrow palpebral fissures, long philtrum, etc, and mental and motor developmental delay were observed. Other characteristic clinical manifestations were anuresis and status nonepileptic myoclonia The finding of delayed myelination of the cerebral white matter was observed on magnetic resonance examination, suggesting that an unknown factor related to myelination in the central nervous system might be localized in band 14q31.

Abnormalities, Multiple↗
PubMed1999

Geranylgeranylacetone induces apoptosis in HL-60 cells.

Geranylgeranylacetone (GGA) induces apoptosis in human leukemia HL-60 cells in a dose- and time-dependent manner. This effect was completely prevented by the pan-caspase inhibitor z-Val-Ala-Asp(OMe) fluoromethylketone, thereby implicating the caspase cascade in the process. Prior to DNA fragmentation, GGA treatment markedly activated caspase-3(-like) proteases, which might be responsible for the observed apoptosis. In addition, GGA treatment interfered with the processing and membrane localization of Rap1 and Ras, and these changes may be a result of apoptosis. Moreover, nitric oxide donors significantly accentuated the GGA-induced apoptosis, suggesting that the apoptotic pathway induced by GGA might be regulated by a redox-sensitive mechanism. Taken together, these data suggest that the isoprenoid, GGA, is an effective inducer of apoptotic cell death in HL-60 cells.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Dimethylarsinic acid exposure causes accumulation of Hsp72 in cell nuclei and suppresses apoptosis in human alveolar cultured (L-132) cells.

We previously found that 72-kDa heat shock protein (Hsp72) was induced and accumulated in the nuclei, together with DNA damage, in human alveolar epithelial (L-132) cells by exposure to dimethylarsinic acid (DMAA), which is a main metabolite of inorganic arsenics in mammals. In the present study, the intracellular behavior of Hsp72 was investigated during the recovery from the DNA damage induced by exposure to DMAA. L-132 cells were exposed to 10 mM DMAA for 3 h, and then incubated in DMAA-free medium. The induction of Hsp72 by exposure to DMAA reached a peak at 6-9 h after removal of DMAA. However, the cell-nuclear distribution of Hsp72 was observed until 3 h after the start of DMAA-free incubation. We further investigated the appearance of apoptosis of L-132 cells after exposure to 10 mM DMAA for 3 h. Internucleosomal DNA fragmentation and morphological changes, as criteria for the evidence of apoptosis, were observed 6-22 h after the start of DMAA-free incubation. The appearance of apoptosis was followed by the release of Hsp72 from the cell nuclei. These results suggest a possibility that the cell-nuclear Hsp72 may suppress the appearance of apoptosis in DNA-damaged cells.

Apoptosis↗
PubMed1999

4-(1-benzoylindol-3-yl)butyric acids and FK143: novel nonsteroidal inhibitors of steroid 5 alpha-reductase (II).

A novel series of indolebutyric acids with varying benzoyl substituents were synthesized to develop nonsteroidal inhibitors of steroid 5 alpha-reductase. We previously reported the discovery of a novel nonsteroidal 5 alpha-reductase inhibitor, FR119680, which had an IC50 value of 5.0 nM against the rat prostatic enzyme. However, this compound was not strongly active against the human prostatic enzyme. By further study of the structure-activity relationships we succeeded in producing the strongly active compound, FK143, 4-[3-[3-[bis(4-isobutylphenyl)-methylamino]benzoyl]-1H-indol-1-yl] butyric acid, with an IC50 value of 1.9 nM against the human enzyme. FK143 also has in vivo inhibitory activity against the castrated young rat model and it should therefore be an extremely useful agent for the treatment of benign prostatic hyperplasia.

5-alpha Reductase Inhibitors↗