Search PubMed⌕ Search

Biomedical subjects

M Aoshima

Publications and source records attributed to M Aoshima.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Allergic granulomatous angiitis associated with cerebral infarction, myo-pericarditis and acute respiratory failure due to eosinophilic pneumonia].

We encountered a 23-year-old woman with allergic granulomatous angiitis (AGA) associated with cerebral infarction, myo-pericarditis, and acute respiratory failure due to extended eosinophilic pneumonia. She underwent emergency treatment at our hospital because of right hemiparesis and impaired consciousness. AGA was suspected because the patient had a history of bronchial asthma accompanied by pulmonary infiltrations with eosinophilia, and presented with diffuse pulmonary infiltrates, pericardial effusion, diffuse hypokinesis of myocardium, cerebral infarction and marked peripheral eosinophlia. Pulmonary eosinophilia was confirmed by examination of broncho-alveolar lavage fluid. Myocardial tissue biopsy specimens revealed fibrous granulation indicative of myocarditis. The patient responded well to corticosteroid therapy.

Acute Disease↗
PubMed1997

Purification and characterization of isocitrate dehydrogenase from a hyperthermophilic archaebacterium, Caldococcus noboribetus.

Isocitrate dehydrogenase from a hyperthermophilic archaebacterium Caldococcus noboribetus produced in Escherichia coli was purified. The purification was performed by heat treatment at 80 degrees C followed by single column chromatography. N-terminal amino acid sequencing analysis revealed that the N-terminal methionine is removed from the purified enzyme. Gel filtration analysis suggests that the enzyme has a homodimeric structure with a molecular weight of 90,000. The isoelectric point of the enzyme was estimated to be 5.6 by isoelectric focusing electrophoresis. The circular dichroism spectrum suggests that the enzyme has a secondary structure consisting of 23% alpha-helix and 34% beta-sheet. Enzymatic activity was observed under neutral pH, and the highest specific activity was obtained using cacodylic acid-KOH (pH 7.0) buffer. MgCl2 or MnCl2 was essential for the activity, and KCl concentrations higher than 0.33 M had an inhibitory effect on it. Apparent Km values were 72 and 43 microM for D,L-isocitrate and NADP, respectively. The enzyme showed extremely high stability against heat treatment, and no activity loss was observed by the treatment at 80 degrees C. The specific activity of the enzyme increased as temperature rose. Nearly no activity was observed at 40 degrees C or lower.

Archaea↗
PubMed1997

Stabilization of Escherichia coli isopropylmalate dehydrogenase by single amino acid substitution.

To determine the key position for the unusual stability of isopropylmalate dehydrogenase from extreme thermophiles (Thermus thermophilus and T. aquaticus), sequence comparisons were carried out. As a result, a motif which is characteristic to the thermophilic dehydrogenases was found between two highly conserved stretches. The sequence motif was introduced into a mesophilic (Escherichia coli) isopropylmalate dehydrogenase, one by one. Contrary to our expectation, introduction of the whole motif led the mesophilic enzyme to be more unstable whereas substitution of only one amino acid residue in the motif thermostabilized the enzyme. From the 3D structure of the enzyme, a mechanism for the thermostabilization is speculated.

3-Isopropylmalate Dehydrogenase↗
PubMed1996

Eubacteria-type isocitrate dehydrogenase from an archaeon: cloning, sequencing, and expression of a gene encoding isocitrate dehydrogenase from a hyperthermophilic archaebacterium, Caldococcus noboribetus.

A gene coding for isocitrate dehydrogenase (ICDH) was cloned from a hyperthermophilic archaebacterium, Caldococcus noboribetus, and sequenced. The gene was preceded by a promoter-like sequence and was followed by a terminator-like sequence. The deduced amino acid sequence of C. noboribetus ICDH showed high similarities to eubacterial ICDH. In particular, extremely high identity scores were found for ICDHs from Vibrio sp. (48.2%) and Escherichia coli (47.9%). The gene was expressed in E. coli by connecting it with the T7 promoter. The molecular weight of the gene product was estimated to be 48,000, which is consistent with that calculated from the deduced amino acid sequence. The gene product showed NADP-dependent ICDH activity at 80 degrees C. While the host-derived ICDH was completely inactivated by treatment at 70 degrees C for 10 min, the ICDH from C. noboribetus showed much higher thermostability.

Amino Acid Sequence↗
PubMed1996

Thioredoxin: a redox-regulating cellular cofactor for glucocorticoid hormone action. Cross talk between endocrine control of stress response and cellular antioxidant defense system.

Adaptation to stress evokes a variety of biological responses, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and synthesis of a panel of stress-response proteins at cellular levels: for example, expression of thioredoxin (TRX) is significantly induced under oxidative conditions. Glucocorticoids, as a peripheral effector of the HPA axis, exert their actions via interaction with a ligand-inducible transcription factor glucocorticoid receptor (GR). However, how these stress responses coordinately regulate cellular metabolism is still unknown. In this study, we demonstrated that either antisense TRX expression or cellular treatment with H2O2 negatively modulates GR function and decreases glucocorticoid-inducible gene expression. Impaired cellular response to glucocorticoids is rescued by overexpression of TRX, most possibly through the functional replenishment of the GR. Moreover, not only the ligand binding domain but the DNA binding domain of the GR is also suggested to be a direct target of TRX. Together, we here present evidence showing that cellular glucocorticoid responsiveness is coordinately modulated by redox state and TRX level and propose that cross talk between neuroendocrine control of stress responses and cellular antioxidant systems may be essential for mammalian adaptation processes.

Animals↗
PubMed1996

Cloning and sequencing of a gene encoding 16S ribosomal RNA from a novel hyperthermophilic archaebacterium NC12.

A hyperthermophile NC12 was newly isolated from Noboribetsu hot spring. To characterize this organism, a gene coding for 16S rRNA was cloned and sequenced. The 16S rRNA sequence from NC12 shows the highest similarity with those from Pyrodictium occultum and Desulfurococcus mobilis among the sequences in the database, indicating that NC12 belongs to a cluster of extreme thermophiles (Crenarchaeota) in the archaeal domain. However, since the highest identity score was only 91.2%, it is suggested that NC12 may constitute a new genus.

Archaea↗
PubMed1996

Two-exon skipping due to a point mutation in p67-phox--deficient chronic granulomatous disease.

The cytosolic 67-kD protein in phagocytes (p67-phox) and B lymphocytes is one of essential components of the superoxide-generating system in these cells, and its defect causes an autosomal recessive type of chronic granulomatous disease (CGD). We performed mutation analysis of p67-phox mRNA from a CGD patient who lacks the protein and found an in-frame deletion from nucleotide 694 to 879, which corresponds to the entire sequence of exons 8 and 9. This sequence encodes one of two Src homology 3 domains and a part of proline-rich domain in p67-phox and lack of these domains seem to have influenced stability of this protein. To know causative reason for the deletion, we analyzed genomic DNA for p67-phox using two sets of primers that covered exons 8 and 9 with adjacent introns. The DNA fragments from the patient were shown to be same in length as those from control. However, the single-strand conformation-polymorphism analysis of the fragments showed that a patient's specimen that included the splice junction of exon 9 exhibited different mobility from the control. By sequencing of the fragment, a homozygous G to A replacement at position +1 of intron 9 was found to be a sole mutation, which reduced the matching score of the splicing sequence to the consensus calculated according to the formula proposed by Shapiro and Senapathy (Nucleic Acids Res 15:7155, 1987). The reduced matching score at the splice doner site (5' splice site) of intron 9 and the original low matching score at the acceptor site (3' splice site) of intron 7 may explain the skipping of exon 8 and 9, and another predicted mechanism is discussed on the basis of Shapiro and Senapathy's hypothesis.

Adult↗
PubMed1996

Increase of sulfated ursodeoxycholic acid in the serum and urine of patients with chronic liver disease after ursodeoxycholic acid therapy.

The present study was undertaken in order to investigate the influence of ursodeoxycholic acid (UDCA) on the composition of sulfate-conjugated bile acids in the serum and urine of patients with chronic active hepatitis and compensated liver cirrhosis. After a 12 week UDCA treatment (600 mg/day), total serum bile acid concentration increased two-fold in patients with compensated liver cirrhosis and increased slightly in patients with chronic active hepatitis. The percentage of sulfated bile acids significantly increased in patients with both compensated liver cirrhosis and chronic active hepatitis. UDCA made up 63% of the total serum bile acids in compensated liver cirrhosis and 61% in chronic active hepatitis after UDCA treatment. Of the serum bile acids after UDCA treatment, 35.2 and 53.9% of UDCA was sulfate conjugated in compensated liver cirrhosis and chronic active hepatitis, respectively. Urinary excretion of total bile acid and UDCA after UDCA treatment in compensated liver cirrhosis were higher than in chronic active hepatitis. UDCA made up 68% of the total urinary bile acids in compensated liver cirrhosis and 64% in chronic active hepatitis after UDCA treatment. Of the urinary bile acids after UDCA treatment, 51.8 and 54.8% of UDCA was sulfate conjugated in compensated liver cirrhosis and chronic active hepatitis, respectively. UDCA treatment for compensated liver cirrhosis was less effective than for chronic active hepatitis. We found that sulfate conjugation is one of the major metabolic pathways for UDCA after UDCA treatment in chronic liver diseases.

Adult↗
PubMed1995

Simultaneous dietary supplementation of sodium cholate and beta-carotene markedly enhances accumulation of beta-carotene in mice.

This study evaluated whether simultaneous supplementation of sodium cholate and beta-carotene to a diet enhanced the accumulation of beta-carotene in mice. For 2 wk, male ICR mice were fed either a basal diet or a diet containing Dunaliella-bardawil beta-carotene 50 mg/100g that was or was not supplemented with sodium cholate (0.25 g/100 g). The concentrations of beta-carotene in liver and plasma were approximately 5 and 10 times higher, respectively. In the mice fed the beta-carotene diet with sodium cholate than in those fed the beta-carotene diet without sodium cholate. Beta-carotene was not detectable in the liver or plasma of mice fed either basal diet. The concentrations of vitamin E in the plasma and liver of mice fed either beta-carotene diet or the basal diet with sodium cholate were significantly lower than in those fed the basal diet. In a second study, mice were fed a diet containing 50 mg/100 g synthetic beta-carotene supplemented with various concentrations of sodium cholate (0, 0.05, 0.1, 0.25, 0.5 g/100 g) for 2 wk. The concentrations of beta-carotene and vitamin E in plasma, liver and bone marrow cells were higher in mice fed the beta-carotene diet supplemented with 0.05 g/100 g of sodium cholate than in those fed the unsupplemented diet. These findings show that simultaneous supplementation of sodium cholate and beta-carotene to a diet markedly enhances the accumulation of beta-carotene. This dietary protocol may be useful to introduce a high amount of beta-carotene in the tissue of mice in a short period of time.

Animals↗
PubMed1995

Feeding of palm oil carotene to mice did not modify X-ray-induced chromosomal damage in bone marrow cells.

The influence of palm oil carotene treatment on X-ray-induced chromosomal damage in bone marrow cells of mice was studied. Palm oil carotene contains alpha- and beta-carotene in a ratio of 1:3. Mice were fed either a basal diet or carotene diet containing 50 mg of palm oil carotene/100 g for 15 days. On day 13, mice to be X-ray-irradiated received 0.5 Gy of X-ray to their whole bodies, and the chromosomal damage in bone marrow cells was evaluated in terms of the percentages of micronucleated reticulocytes in their peripheral blood on day 15. The chromosomal damage in the X-ray irradiated mice was 10 times higher than that in the unirradiated mice. The feeding of the carotene diet did not prevent the X-ray-induced chromosomal damage. In the bone marrow cells of mice fed the carotene diet, alpha- and beta-carotene were detected, but the concentration of the carotenes was less than one-hundredth of that of vitamin E. In addition, the feeding of carotene diet markedly reduced the concentration of vitamin E in bone marrow cells and serum. The X-ray irradiation reduced the concentration of vitamin C in the bone marrow cells, but did not reduce that of vitamin E or carotene in the cells.

Animals↗
PubMed1995

[Conjugated bile acid profiles in serum, urine, and bile of patients with primary biliary cirrhosis under the ursodeoxycholic acid treatment].

We studied the conjugated bile acid profiles (sulfate, glucuronide, and nonsulfate-nonglucuronide) in serum, urine, and bile of 12 patients with primary biliary cirrhosis (PBC) before and under the ursodeoxycholic acid therapy (UDCA, 600mg/day, 6-8 months). Serum total bile acid concentration in those patients without the UDCA therapy was several times higher than those of healthy volunteers, and the percentage of sulfate to total bile acid was 24.8%. After the UDCA therapy, serum total bile acid concentration increased making a progression of Scheuer's stage. In patients with stage I-III, the percentage of sulfate to total was 13.7-65.0% (32.5%, mean), and that of glucuronide to total was 6.6-43.3% (24.0%). Then, the sum of sulfate and glucuronide conjugates was more than 50% to total. Although in patients with stage IV, serum total bile acid level rose markedly, the percentages of sulfate and glucuronide highly reduced. In urine of patients with stage I-III, a large amount of sulfate and glucuronide was found and the percentage of both conjugates was more than 65% of total. On the other hand, sulfate and glucuronide conjugates were only minor component in bile. Based on these data, we might be led to the following conclusion: (1) in patients with PBC (stage I-III), sulfated conjugates of serum bile acid are not minor component, (2) the increased UDCA in serum of patients with PBC during the UDCA treatment might be more easily extracted into urine as sulfate and glucuronide UDCA.

Aged↗
PubMed1995

[Non-Hodgkin's lymphoma presenting as a soft tissue tumor in the connective tissue at the thigh].

A 62-year-old man visited our hospital in July 1993, because of a right thigh mass which had grown gradually since two years previously. Physical examination revealed that the mass at the right thigh region, was elastic soft and about 15 x 10 cm in diameter, without regional lymph node swelling. An ultrasound study showed a hypoechogenic and mesh patterned mass. MRI revealed that the tumor was well defined from subcutaneous adipose tissue and skeletal muscle, indicating that it arose in connective tissue. Angiography demonstrated diffuse hypervascularization of the tumor, and Gallium scintigraphy showed remarkable accumulation at the tumor. Serum IgM was increased, which was proven to be an monoclonal hypergammopathy (IgM, lambda). Histological examination of a biopsied specimen obtained from the thigh mass revealed B cell lymphoma, lymphoplasmacytic cell type. The patient achieved a complete remission after surgical treatment following radiation and combination chemotherapy.

Humans↗
PubMed1995

[Mechanical ventilation and long-term respiratory care in the intensive care unit of a general hospital].

We studied the need for mechanical ventilation in 265 patients with respiratory failure who came to our medical ICU over the past 3 years. The time required for weaning from mechanical ventilation and the percentage of patients who needed oxygen therapy or mechanical ventilation at home after their condition was no longer acute were also studied. Of the patients treated in the medical ICU, 143 (54%) required mechanical ventilation; 104 (39%) had acute respiratory failure and the others had acute exacerbations of chronic respiratory failure. Some causes of acute respiratory failure were aspiration pneumonia, bronchial asthma, and drug use. Three-fourths of those with chronic respiratory failure had pulmonary emphysema, sequela of pulmonary tuberculosis, or idiopathic interstitial pneumonia. In patients with chronic respiratory failure, success in weaning could be predicted from the respiratory index (PaO2/FIO2), the serum albumin level, and the length of time that they were ventilated with more than 60% oxygen. Thirteen patients with chronic respiratory failure died while receiving mechanical ventilation. Of those who survived, 11 underwent tracheostomies, and 4 of those 11 were mechanically ventilated at home with portable devices. Ten other survivors received home oxygen therapy. Chest physicians bear the greatest responsibility for managing mechanical ventilation in medical emergencies. Moreover, the prognosis for patients with chronic respiratory failure can be improved with a long-term program for respiratory care that includes home mechanical ventilation and home oxygen therapy.

Adult↗
PubMed1994

High-level expression of Mycoplasma arginine deiminase in Escherichia coli and its efficient renaturation as an anti-tumor enzyme.

The arginine deiminase (AD) gene was cloned from Mycoplasma arginini and expressed in the cytosol of Escherichia coli as inclusion bodies with an expression level of at least 20% of the total bacterial proteins. The inclusion bodies were solubilized with 6 M guanidine hydrochloride (Gdn-HCl) under reducing conditions, in order to avoid incorrect disulfide-bond formation of the recombinant (r-) AD molecules, and renaturation was performed under various refolding conditions. The optimum renaturation conditions were found to be incubation for 90 h at pH 7.5 and 15 degrees C. The resulting completely refolded r-AD was purified to homogeneity by anion-exchange and arginine-affinity chromatography and its activity yield was 72.5%. The specific activity of the purified r-AD was comparable to and its amino acid composition was identical to those of Mycoplasma AD, and NH2-terminal sequence analysis revealed that its methionine residue corresponding to the translation initiation codon had been removed completely. Anti-tumor activity analyses showed that r-AD inhibited the growth of two mouse cell lines, hepatoma MH134 and fibrosarcoma Meth A, strongly in vitro at concentrations in excess of 10 ng ml-1. Moreover, when MH134-implanted mice were given single intravenous injections of r-AD at doses of 50 mg kg-1 and higher, their survival times were prolonged significantly. These results, taken together, indicate that the enzymatic properties and biological actions of r-AD were highly consistent with those of Mycoplasma AD.

Amino Acid Sequence↗
PubMed1994

Hydrophobic interaction at the subunit interface contributes to the thermostability of 3-isopropylmalate dehydrogenase from an extreme thermophile, Thermus thermophilus.

We cloned and sequenced the leuB gene encoding 3-isopropylmalate dehydrogenase from Escherichia coli K-12 (JM103). Errors (33 residues) were found and corrected in the sequence previously reported for the leuB gene of Thermus thermophilus. The three-dimensional structure of the thermophile enzyme and the amino acid sequence comparison suggested that a part of the high stability of the T. thermophilus enzyme is conferred by increased hydrophobic interaction at the subunit-subunit interface. Two residues at the interface of the T. thermophilus enzyme, Leu246 and Val249, are substituted with less hydrophobic residues, Glu and Met, respectively, in the E. coli enzyme, whereas other residues in this region are highly conserved. The mutated T. thermophilus enzyme [L246E, V249M]IPMDH had reduced stability to heat. Two residues of the E. coli dehydrogenase, Glu256 and Met259, were replaced with the corresponding residues from the thermophile sequence. The resulted mutant enzyme was more resistant to heat than the wild-type enzyme.

3-Isopropylmalate Dehydrogenase↗