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Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 271 records · Page 15Linked to original sources
PubMed2001

Production and characterization of recombinant Phanerochaete chrysosporium cellobiose dehydrogenase in the methylotrophic yeast Pichia pastoris.

The hemoflavoenzyme cellobiose dehydrogenase (CDH) from the white-rot fungus Phanerochaete chrysosporium has been heterologously expressed in the methylotrophic yeast Pichia pastoris. After 4 days of cultivation in the induction medium, the expression level reached 1800 U/L (79 mg/L) of CDH activity, which is considerably higher than that obtained previously for wild-type CDH (wtCDH) and recombinant CDH (rCDH) produced by P. chrysosporium. Analysis with SDS-PAGE and Coomassie Brilliant Blue (CBB) staining revealed a major protein band with an approximate molecular mass of 100 kDa, which was identified as rCDH by Western blotting. The absorption spectrum of rCDH shows that the protein contains one flavin and one heme cofactor per protein molecule, as does wtCDH. The kinetic parameters for rCDH using cellobiose, ubiquinone, and cytochrome c, as well as the cellulose-binding properties of rCDH were nearly identical to those of wtCDH. From these results, we conclude that the rCDH produced by Pichia pastoris retains the catalytic and cellulose-binding properties of the wild-type enzyme, and that the Pichia expression system is well suited for high-level production of rCDH.

Carbohydrate Dehydrogenases↗
PubMed2001

Antimutagenic activity against trp-P-1 of the edible Thai plant, Oroxylum indicum vent.

A methanolic extract of Oroxylum indicum strongly inhibited the mutagenicity of Trp-P-1 in an Ames test. The major antimutagenic constituent was identified as baicalein with an IC50 value of 2.78+/-0.15 microM. The potent antimutagenicity of the extract was correlated with the high content (3.95+/-0.43%, dry weight) of baicalein. Baicalein acted as a desmutagen since it inhibited the N-hydroxylation of Trp-P-2.

Antimutagenic Agents↗
PubMed2001

Radicicol binding to Swo1/Hsp90 and inhibition of growth of specific temperature-sensitive cell cycle mutants of fission yeast.

A panel screening using cdc mutants of Schizosaccharomyces pombe identified radicicol as a potent growth inhibitor of certain mutants at the permissive temperature. The strains sensitive to radicicol were cdc7, cdc11, and cdc14, all of which are defective in early septum formation. Cytokinesis but not nuclear division of these mutants was inhibited by radicicol, but that of cells with the wild-type background was not. A biologically active derivative of radicicol with a biotin moiety at the C-11 position bound Swo1, an Hsp90 homologue in S. pombe. Increased Swo1 expression partially suppressed radicicol sensitivity of cdc14 and almost completely rescued morphological abnormalities in cdc14 and cdc7 cells induced by radicicol at the permissive temperature. On the other hand, the increased Swo1 expression did not restore septum formation at the nonpermissive temperature. These results suggest that Swo1, as a molecular chaperone, plays a role in stabilizing these temperature-sensitive proteins at the permissive temperature or in activating the cytokinesis signaling cascade.

Antifungal Agents↗
PubMed2001

Characterization of the pro-aminopeptidase from Aeromonas caviae T-64.

The pro-aminopeptidase from Aeromonas caviae T-64 (pro-apAC) had maximal activity at 60 degrees C and was more stable than mature apAC at temperature up to 65 degrees C for 1 hour. The pH stability of pro-apAC ranged from 4.0 to 8.0, which is broader than the range for the mature apAC. The kcat/Km of pro-apAC was 1.4% to 24% of that of mature apAC.

Aeromonas↗
PubMed2001

A family with von Hippel-Lindau disease revealed by pheochromocytoma.

Von Hippel-Lindau (VHL) disease is an inherited neoplastic disease characterized by a predisposition to develop retinal angiomas, central nervous system hemangioblastomas, renal cell carcinomas, pancreatic cysts and pheochromocytomas. Recently, we encountered three members of the same family who each had both VHL disease and pheochromocytoma. As in all three patients we suspected pheochromocytoma, the diagnosis of VHL disease should be considered. The possible presence of VHL disease was initially investigated in all three patients based on the presence of pheochromocytoma. A mutational analysis of the VHL gene revealed the presence of a missense mutation, consisting of a G to A transversion, at nucleotide 713 in all three patients. This germline point mutation in the VHL gene is often detected in type 2 VHL disease with pheochromocytoma. Genetic analysis seems to be useful for early detection of VHL disease, even when the formal criteria for diagnosis of this disease are lacking.

Adrenal Gland Neoplasms↗
PubMed2001

Biosynthesis and secretion of adrenomedullin and proadrenomedullin N-terminal 20 peptide in a rat model of endotoxin shock.

To study the biosyntheses and pathophysiological roles of adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) in septic shock, we compared the time course of plasma concentrations of these peptides and blood pressure in rats injected with either 0.9% saline (control group) or lipopolysaccharide (LPS group). The plasma AM concentration in the LPS group did not increase 30 and 60 min after LPS injection, at which time points the blood pressure remained low. Thereafter, AM rapidly increased, and it amounted to 35 times the basal value 4 h after injection, when the blood pressure returned to the basal level. The increment of plasma PAMP in the LPS group was lower than that of AM. We also examined the tissue concentration of AM and PAMP--as well as the tissue expression of proadrenomedullin (proAM) mRNA--in the LPS and control groups. LPS significantly increased the tissue concentrations of AM and PAMP in the lung, but decreased them in the adrenal gland and cardiac atrium. The LPS injection augmented proAM gene transcription in the lung, adrenal gland and aorta. In an immunohistochemical examination, AM staining was intense in alveolar endothelial cells of the lung in the LPS group. Thus, this septic shock model had high plasma levels of PAMP as well as AM, while the biosynthesis and secretion of the two peptides may have been differentially regulated in various tissues of rats injected with LPS. The present results suggest that these two bioactive peptides may play different roles in the pathophysiology of septic shock.

Adrenomedullin↗
PubMed2001

An investigation of heavy metal exposure and risks to wildlife in the Kafue flats of Zambia.

Exposure and ecological risks to heavy metals (copper, zinc, manganese, iron) at Lochnivar and Blue Lagoon National Parks in wildlife dependent on the Kafue river contaminated with mining waste was evaluated. Samples included water, fish, grasses and Kafue Lechwe (Kobus leche kafuensis) liver. At both parks copper ranged from 0.03-0.04 mg/l; 3.0-6.0 mg/kg; 11.0-44.0 mg/kg; trace -199.0 mg/kg; while zinc was 0.01 mg/l; 32.0-82.0 mg/kg; 15.0-21.0 mg/kg; and 52.0-138.0 mg/kg; in water, fish, grasses and lechwe, respectively. Manganese ranges were 0.15-0.16 mg/l; 7.0-18.0 mg/kg; 51.0-145.0 mg/kg; and 40.0-53.0 mg/kg while iron ranges were 0.13-0.14 mg/l; 26.0-134.0 mg/kg; 1766.0-1797.0 mg/kg; and 131.0-856.0 mg/kg; in water, fish, grasses and lechwe, respectively. Levels in all samples except water were high indicating potential for adverse effects.

Animals↗
PubMed2001

The polymorphism in the caudal-related homeodomain protein Cdx-2 binding element in the human vitamin D receptor gene.

The major physiological activity of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] is the regulation of calcium absorption in the small intestine, and the level of vitamin D receptor (VDR) is an important factor in this regulation. In a previous study, we indicated-that the caudal-related homeodomain Cdx-2 played an important role in the intestine-specific transcription of the human VDR gene. In this study, the polymorphism was identified in the core sequence 5'-ATAAAAACTTAT-3' in the Cdx-2 binding site in the VDR gene promoter. In 261 Japanese women with genotyped VDR polymorphisms, 48 were genotype Cdx-A (adenine at -3731 nucleotides [nt] relative to the transcription start site of human VDR gene 5-ATAAAAACTTAT), 82 were genotype Cdx-G (guanine at -3731 nt, 5'-GTAAAAACTTAT-3'), and 131 were genotype Cdx-A/G (heterozygote). In postmenopausal Japanese women, the bone mineral density (BMD) in the lumbar spine (L2-L4) with the Cdx-G homozygote was 12% lower than that with the Cdx-A homozygote (p < 0.05). In electrophoretic gel mobility shift assay (EMSA), the oligonucleotide with Cdx-G allele markedly decreased the binding to Cdx-2 compared with that in the Cdx-A allele. The transcriptional activity of the VDR promoter with Cdx-G allele was decreased to 70% of the Cdx-A allele. In addition, in the herpes simplex virus thymidine kinase promoter, the Cdx-2 binding element with the G allele showed significantly lower transcriptional activity than that of the A allele. Thus, the polymorphism in the Cdx-2 binding site of the VDR gene (Cdx-polymorphism) would affect the expression of VDR in the small intestine. In addition, this polymorphism may modulate BMD in postmenopausal Japanese women.

Adult↗
PubMed2001

A light microscope study of the distribution of muscle in the frog esophagus and stomach.

The present study reports light microscopical observations of the distribution of muscle in the esophagus and stomach of both the bull frog (Rana catesbeiana) and the African clawed frog (Xenopus laevis). The external muscle coat of the upper half of the esophagus in both species had several collagen coated bundles of striated muscle fibres around the circumference. These striated muscle bundles ran longitudinally from the pharynx to around the vicinity of the center of the esophagus. Beneath these striated muscle bundles was an inner circular layer of smooth muscle. In both species, the inner circular layer of smooth muscle was particularly thick in the region close to the pharynx. In the bull frog, the lower half of the esophagus lacked striated muscle. However, the circular smooth muscle layer, extending from the upper half of the esophagus, was also observed throughout the lower half of the esophagus. An outer longitudinal layer of smooth muscle developed towards the terminal portion of the esophagus such that in this region, both outer longitudinal and inner circular layers of smooth muscle were observed. Similarly in the African clawed frog, the inner circular layer of smooth muscle was continuous along the full length of the esophagus. Again, no striated muscle bundles were observed in the lower half of the esophagus. However, the outer longitudinal layer of smooth muscle was seen to develop in the middle region of the esophagus. Its muscle layer extended to the terminal portion of the esophagus. Thus, both outer longitudinal and inner circular layers of smooth muscle were observed throughout the lower half of the esophagus. In both frogs, the thickness of the outer longitudinal and inner circular layers of smooth muscle changed before and after the esophago-gastric junction. In both frogs, no muscularis mucosa was observed in the esophageal wall. However, in the lower half of the esophagus of the African clawed frog, small bundles of smooth muscle were observed here and there in the submucosa. A fully developed muscularis mucosa with both outer longitudinal and inner circular layers was observed in the upper stomach of both frogs.

Animals↗
PubMed2001

Effects of mechanical stimulation on gene expression of articular chondrocytes in polylayer culture.

Mechanical loads are constantly being applied to articular cartilage. However, comparatively few studies have investigated the effects of mechanical stress on the gene expression of chondrocytes. Hence, the objective of the present study was to clarify the effects of mechanical stress on cultured chondrocytes. Articular chondrocytes of rabbits were isolated and placed in minimun essential medium eagle a modification containing 10% fetal bovine serum. The chondrocytes were cultured in polylayer in polypropylene tubes. After 48 hours, centrifugal stress (2.7 MJ) was applied once every 24 hours for 28 consecutive days. The mRNA expression of insulin-like growth factor-I (IGF-I) and cartilage-specific genes (type II collagen and aggrecan) in chondrocytes, cell count, wet tissue mass and protein content were subsequently measured. The results showed that the mRNA expression of the IGF-I gene for the stress groups was significantly greater than that of the control group from days 3 to 5 of incubation, as was the mRNA expression of the type II collagen gene from days 7 to 14 of incubation. However, there were no significant differences in the mRNA expression of the aggrecan gene between the control and stress groups. The cell count for the stress groups was significantly higher from days 7 to 28 of incubation, and the wet tissue mass and protein content were significantly higher from days 14 to 28 of incubation. These findings suggest that one of the mechanisms by which mechanical stress increases the number of cultured chondrocytes and the volume of extracellular matrix is to increase IGF-I expression at the early stage of incubation.

Aggrecans↗
PubMed2001

Activation of mitochondrial ATP-dependent protease by peptides and proteins.

We examined the effect of peptides or protein on the proteolytic and ATPase activities of mitochondrial ATP-dependent LON protease purified from bovine adrenal cortex. Peptides/proteins including angiotensin I which stimulated ATPase activity without hydrolysis of any peptide bonds stimulated proteolysis of 125I-labeled substrates at low concentrations; whereas at high concentrations they competitively inhibited proteolysis, thus displaying a biphasic activity profile. All peptides and proteins thus examined stimulated degradation of 125I-labeled substrates. When an ATP analog was substituted for ATP, only inhibition; i.e., no stimulation, of proteolysis by unlabeled peptides was observed. Without activator peptides, degradation of [125I] peptides was higher in the presence of an ATP analog than that in the presence of ATP. ADP, a product of the ATPase reaction, inhibited the proteolytic activity in the absence of an activator peptide but not in its presence. From analogy to E. coli ATP-dependent protease La (LON), we suggest that the activator peptides stimulated the proteolysis by releasing enzyme-bound ADP.

ATP-Dependent Proteases↗
PubMed2001

Kinetically controlled separation of cadmium(II) from zinc(II) with dithizone in the presence of nitrilotriacetic acid.

The extraction rates of cadmium(II) and zinc(II) with dithizone (H2dz) in the presence of nitrilotriacetic acid (NTA) were measured, and the possible kinetic separation of cadmium(II) from zinc(II) was investigated. Upon the addition of NTA, the difference in the extraction rate between cadmium(II) and zinc(II) became large. Based on the observed rate constant under the condition [NTA] = 1 x 10(-2) mol dm-3, [H2dz]org = 1 x 10(-3) mol dm-3, and pH = 7.0, the shaking time required for the quantitative separation of cadmium(II) from zinc(II) was calculated to be between 326 and 995 s. The experimental results agreed with the prediction, and the quantitative separation of cadmium(II) from zinc(II) was performed within the above-mentioned range of shaking times.

Journal Article↗
PubMed2001

Protein-losing enteropathy exacerbated with the appearance of symptoms of systemic lupus erythematosus.

A 38-year-old woman visited our hospital with edema on her face and conjunctivae. The underlying disease was not clarified, and she did not visit the hospital afterwards. She suffered from diarrhea, polyarthralgia, Raynaud's phenomenon, malar rash and hair loss in the subsequent two years, and was hospitalized because of hypoproteinemia. Her urine, liver and heart test results did not account for her hypoproteinemia. She was diagnosed as having protein-losing enteropathy (PLE) associated with SLE based on the 99mtechnetium-labeled human serum albumin scintigraphy findings, clinical findings and laboratory results of antinuclear and anti-Sm antibodies. This case report demonstrates a strong association between PLE and SLE because PLE was aggravated along with the appearance of SLE symptoms and PLE subsided with prednisolone treatment along with improvement of SLE.

Adult↗
PubMed2001

Proteomics as a tool in the pharmaceutical drug design process.

Proteomics is a technology platform that is gaining widespread use in drug discovery and drug development programs. Defined as the protein complement of the genome, the proteome is a varied and dynamic repertoire of molecules that in many ways dictates the functional form that is taken by the genome. The importance of proteomics is a direct consequence of the central role that proteins play in establishing the biological phenotype of organisms in healthy and diseased states. Moreover, proteins constitute the vast majority of drug targets against which pharmaceutical drug design processes are initiated. By studying interrelationships between proteins that occur in health and disease and following drug treatment, proteomics contributes important insight that can be used to determine the pathophysiological basis for disease and to study the mechanistic basis for drug action and toxicity. Proteomics is also an effective means to identify biomarkers that have the potential to improve decision making surrounding drug efficacy and safety issues based on data derived from the study of key tissues and the discovery and appropriate utilization of biomarkers.

Chromatography, High Pressure Liquid↗
PubMed2001

Magnitude of the regression to the mean within one-year intra-individual changes in serum lipid levels among Japanese male workers.

To investigate the magnitude of the 'regression to the mean' effect for the changes in serum total cholesterol (TC), triglycerides (TG), and high density lipoprotein cholesterol (HDLC) levels during one-year interval between annual health check-ups in occupational settings, the relationships between the baseline level and subsequent one-year change in TC, TG or HDLC were analyzed using paired health check-up data in 1998 and 1999 of 547 Japanese male clerical workers. After adjustment for age, body mass index (BMI), yearly change in BMI, drinking score and smoking score by the multivariate analyses, the yearly changes in each serum lipid (deltaTC, deltaLn(TG) or deltaHDLC) were clearly inversely associated with the lipid levels in 1998. For example, in the multiple linear regression analyses setting delta value in each serum lipid as a dependent variable, the partial regression coefficients for the baseline lipid levels (beta1) were - 0.21 (p<0.001) for the TC, -0.39 (p<0.001) for the Ln(TG) and -0.15 (p<0.001) for the HDLC, respectively. These results suggest that the observed yearly change in each serum lipid level may largely reflect the 'regression to the mean' effect in addition to the real yearly biological change.

Adult↗
PubMed2001

[Oral care reduces pneumonia of elderly patients in nursing homes, irrespective of dentate or edentate status].

Aspiration of oral secretions and their bacteria, especially gram-negative bacilli, is increasingly being recognized as an important factor in pneumonia. We investigated whether oral care reduces the frequency of pneumonia in the institutionalized elderly. Nurses or caregivers cleaned patients' teeth with toothbrushes after each meal, and scrubbed the oropharynx with an applicator with povidone iodine (1%) every day. Dentists or dental hygienists gave professional care once a week. During follow up, pneumonia decreased significantly in patients with oral care. Oral care was of benefit for both edentate as well as dentate subjects, although periodontal diseases might cause pneumonia. We suggest that oral care may be useful in preventing pneumonia in institutionalized elderly, irrespective of dentate or edentate status.

Aged↗
PubMed2001

Quantitative evaluation of selenium contained in tea by high performance liquid chromatography.

For determination of selenium (Se) in biological materials, an improved method based on high performance liquid chromatographic determination of the fluorophore formed by reaction of selenite with 2,3-diaminonapththalene was developed. The concentration detection limits were 0.5 ng/g in dried materials and 0.03 ng/mL in fluid materials. In quadruplicate assays of 11 biological reference materials using the proposed method, measured Se concentrations were not significantly different from their certified values. Thus, the proposed method is reliable and suitable for the determination of trace levels of Se in foods. Using the proposed method, Se concentrations in various kinds of tea were determined to assess the contribution of tea to daily Se intake in the Japanese population. Se concentration in the leaves of general black, green and oolong tea obtained in local retail stores was 33 +/- 19 ng/g (n=440). The leaves of a particular Chinese green tea sold under the name "high Se tea" were found to contain 455 +/- 184 ng/g (n= 14) of Se. While the percentage of Se extractable by infusion was less than 5% for the general teas, that in the high Se tea was more than 20%. These results indicated that intake of tea does not contribute to daily Se intake in the Japanese population. However, since infusions from high Se tea contained over 5 ng/mL of Se, consumption of over 1 L/d of tea derived from such high Se teas may increase the daily Se intake by close to 10%.

2-Naphthylamine↗