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Biomedical subjects

T Uchiyama

Publications and source records attributed to T Uchiyama.

At least 145 records · Page 8Linked to original sources
PubMed1999

Molecular cloning and nucleotide sequencing of organophosphorus insecticide hydrolase gene from Arthrobacter sp. strain B-5.

The organophosphorus insecticide hydrolase (OPH) gene of Arthrobacter sp. strain B-5, isolated from turf green soil was cloned into Escherichia coli JM109. Three clones, termed EpB511, EpB521 and EpB531, exhibiting OPH activity were obtained. However, these three clones showed lower OP-degrading ability than strain B-5. A 7.7-kb inserted fragment of the plasmid pB521 harbored by EpB521 was subcloned, resulting in construction of a plasmid, pB526, carrying the 2.6-kb inserted fragment with OP-degrading ability. In this sequence, an open reading frame (ORF) that encodes a 43,607 Da polypeptide composed of 415 amino acids was identified. The N-terminal amino acid sequence deduced from the nucleotide sequence was identical to that of purified OPHs. The deduced amino acid sequence was compared with the sequences in the data bank and a 58.1% amino acid identity was found with the aryldialkylphosphatase from Nocardia sp. strain B-1, an enzyme that possesses catalytic functions similar to OPH.

Journal Article↗
PubMed1999

Changes in cortical width with bone turnover in the three different endosteal envelopes of the ilium in postmenopausal osteoporosis.

Histological indicators of bone turnover were compared in the three endosteal envelopes (cancellous, endocortical, and intracortical) of iliac bone specimens obtained from 82 osteoporotic women, to assess the correlation between bone turnover and bone volume in different remodeling sites. Although there was a significant but weak correlation between the mineral apposition rate (MAR), a histological indicator of bone formation at the basic multicellular unit (BMU) level, and the three endosteal envelopes, the bone formation rate corrected for bone surface (BFR/BS) and mineralizing surface (MS/BS), indicators of the rate of bone formation reflecting activation frequency, in the cancellous and endocortical envelopes was more closely related to the rate in the intracortical envelope. The endocortical BFR/BS and MS/BS were higher than the rate in the cancellous envelope (1.6-2.1 times and 2.0-2.4 times, respectively), indicating a higher turnover rate in the endocortical envelope. According to stepwise regression analysis of the significant determinants contributing to bone mass, several histological determinants relating to bone turnover were identified: (1) trabecular thickness (Tb.Th) was a positive determinant, whereas age and cancellous bone volume referent BFR (BFR/BV) were negatively correlated determinants of the cancellous bone volume (BV/TV) (R2 = 0.50, p < 0.001); and (2) the endocortical wall thickness (W.Th) of the given side and the cortical width (Ct.Wi) of the opposite side were positive determinants, whereas the cancellous osteoid surface (OS/BS), cancellous MAR, and endocortical eroded surface (ES/BS) of the given side were the negatively correlated determinants of the Ct.Wi of the thicker cortex (R2 = 0.62, p < 0.001). In the thinner cortex, the endocortical W.Th of the given side and Ct.Wi of the opposite side were only used as the positive determinants of the Ct.Wi of the given side (R2 = 0.55, p < 0.001). In addition: (3) a significant but weak correlation was found using the intracortical BFR/BV as a positively correlated determinant of the cortical porosity (Ct.Po) in the thicker cortex (R2 = 0.17, p < 0.01). Although these histological determinants do not fully explain the mechanisms of bone loss, an increased rate of bone turnover contributes to bone loss not only in the cancellous and intracortical envelopes, but also in the endocortical envelope, indicating increased endocortical bone resorption in osteoporosis.

Aged↗
PubMed1999

Three-dimensional microstructural analysis of human trabecular bone in relation to its mechanical properties.

The purpose of this preliminary study is to explore the relationship between elastic modulus, bone mineral density (BMD), and trabecular microstructure in three dimensions. Twenty cubes of trabecular bone were processed from two lumbar vertebrae obtained from one individual. The BMD of each cube was measured by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Each cube was serially scanned by microcomputed tomography to produce three-dimensional data sets. By analyzing these data sets, three-dimensional trabecular microstructural indices of connectivity density and fractal dimension were calculated as well as histomorphometric parameters. The cubes were tested mechanically in a nondestructive manner for measurement of their elastic modulus. This preliminary study showed that: (1) bone mass index is correlated with mechanical properties, with coefficients of correlation ranging from 0.552 to 0.601; and (2) when controlling for BMD, no association could be detected between measures of structural complexity (connectivity density and fractal dimension) and elastic modulus in the craniocaudal direction of human vertebral bodies.

Biomechanical Phenomena↗
PubMed1999

Identification of an adhesion molecule expressed on adult T cell leukemia cells derived from a patient with gastrointestinal involvement: implication for a possible role of integrin beta 7 in leukemic cell infiltration into intestinal mucosa.

Patients with adult T cell leukemia (ATL) often manifest leukemic cell infiltration into various organs such as lung, liver, skin, and gut. To analyze the mechanism of intestinal infiltration of ATL cells, we made mAbs against ATL-43T, a human T cell line derived from an ATL patient with severe intestinal mucosal infiltration. One of the mAbs, named H920, was noted for a high and relatively specific reactivity with ATL-43T. Molecular cloning was done to identify this molecule and disclosed that the Ag molecule was identical to integrin beta 7. Since integrin beta 7 and its ligand MAdCAM-1 had been reported to mediate homing of lymphocytes to endothelial cells in intestinal mucosa, we next examined wither ATL-43T cells could adhere to MAdCAM-1+ cells. Human MAdCAM-1 transfectants of MMCE, a mouse epithelial cell line, were made and used to evaluate cell adhesion mediated by integrin beta 7 and MAdCAM-1. Considerable levels of cell adhesion were observed between ATL-43T and the transfectant cells, which was inhibited by H920 mAb in a dose-dependent manner. Furthermore, peripheral blood leukemic cells or lymphoma cells from 10 ATL patients were examined for expression of integrin beta 7 with regard to organ involvement. Samples from three patients with gastrointestinal tract involvement showed considerably higher expression of integrin beta 7. These results suggest that integrin beta 7 may play a role in adhesion and subsequent infiltration of a certain type of ATL cells into intestinal mucosa.

Adult↗
PubMed1999

Sequence analysis of the gene encoding the major outer membrane protein rOmp B of Rickettsia japonica.

The complete nucleotide sequence of the gene encoding rOmp B (ompB), one of the two major outer membrane antigen proteins, of Rickettsia japonica was determined and compared to those of the other spotted fever group and typhus group rickettsiae. Open reading frame of the ompB gene of R. japonica consisted of 4,968 nucleotides coding for a putative precursor protein with 1,656 amino acids (aa) in which the N-terminal 1,363 aa and the C-terminal 293 aa encode 135-kilodalton rOmp B and 32-kilodalton beta-peptide, respectively. Putative promoter and terminator sequences for transcription were present in the upstream region of the ATG start codon and downstream of the TAA stop codon. Overall sequences of the ompB genes were well conserved beyond the group, especially in the beta-peptide regions.

Amino Acid Sequence↗
PubMed1999

Phenotypic and genotypic homogeneity of the strains of Rickettsia japonica isolated from patients with Oriental spotted fever.

Nine pathogenic strains of Rickettsia japonica isolated from patients with Oriental spotted fever were compared phenotypically and genotypically. Constitution and antigenicity of the proteins demonstrated to be the same among strains. Polymerase chain reaction (PCR) amplification of the two major outer membrane protein genes (ompA and ompB) and an intracellular spotted fever group-common antigen protein gene (rps120) produced the same sizes of products for all strains. Restriction fragment length polymorphism of the PCR products showed the same pattern among strains with each endonuclease. Thus, these strains belong to a single type, the same as the type strain YH (=ATCC VR-1363).

Bacterial Outer Membrane Proteins↗
PubMed1999

Sequence analysis of the gene encoding a spotted fever group-specific intracytoplasmic protein PS120 of Rickettsia japonica.

The 3,438-nucleotide (nt) sequence containing a 3,054-nt open reading frame of the gene (rps120) encoding an antigenic, intracytoplasmic, spotted fever group-specific and heat-stable 120-kilodalton protein (PS120) of Rickettsia japonica was determined. The nt and deduced 1,018 amino-acid (aa) sequences were compared to those of R. conorii since only those of this species had been determined among SFG rickettsiae. The homologies of these sequences between R. japonica and R. conorii were considerably high at 97 and 95%, respectively. These high homologies were comparable to those of beta-peptides encoded by the ompB genes among SFG rickettsiae. It was also found that the genome of R. prowazekii contained a nt sequence with 68% homology to that of the rps120 gene of R. japonica.

Amino Acid Sequence↗
PubMed1999

Urinary function in elderly people with and without leukoaraiosis: relation to cognitive and gait function.

OBJECTIVES: To investigate urinary function in the elderly with and without white matter lesion (leukoaraiosis) in relation to cognitive and gait function. METHODS: Sixty three subjects were examined, with mean age 73 (range 62 to 86 years). Subjects with brainstem stroke or with large hemispheric lesions were excluded. Spin echo 1.5 T MRI images were graded from 0 to 4 for severity of white matter lesions. Urinary function was assessed by detailed questionnaire and urodynamic studies were performed in 33 of the subjects, including measurement of postmicturition residuals, water cystometry, and sphincter EMG. A mini mental state examination (MMSE) and examination of gait was also performed and compared with urinary function. RESULTS: Urodynamic studies showed subjects with grade 1-4 white matter lesions to have detrusor hyperreflexia more commonly (82%) than those with grade 0 white matter lesions (9%) (p<0.05), indicating that leukoaraiosis was a factor associated with geriatric urinary dysfunction. Postmicturition residuals, low compliance, detrusor-sphincter dyssynergia, and uninhibited sphincter relaxation were also more common in grade 1-4 than in grade 0 white matter lesions, though the difference was not significant. In grade 1 white matter lesions urinary dysfunction (urge urinary incontinence) was more common than cognitive (MMSE<19) (p<0.05) and gait disorders (slowness, short step/festination, and loss of postural reflex) (p<0. 05), which increased together with the grade of white matter lesions (p<0.05). CONCLUSIONS: Urinary dysfunction is common and probably the early sign in elderly people with leukoaraiosis on MRI.

Aged↗
PubMed1999

Enhanced permeability of insulin across the rat intestinal membrane by various absorption enhancers: their intestinal mucosal toxicity and absorption-enhancing mechanism of n-lauryl-beta-D-maltopyranoside.

We have examined the in-vitro permeability characteristics of insulin in the presence of various absorption enhancers across rat intestinal membranes and have assessed the intestinal toxicity of the enhancers using an in-vitro Ussing chamber method. The absorption enhancing mechanism of n-lauryl-beta-D-maltopyranoside was studied also. The permeability of insulin across the intestinal membranes was low in the absence of absorption enhancers. However, the permeability was improved in the presence of enhancers such as sodium glycocholate and sodium deoxycholate in the jejunum, and sodium glycocholate, sodium deoxycholate, n-lauryl-beta-D-maltopyranoside, sodium caprate and ethylenediaminetetraacetic acid (EDTA) in the colon. Overall, the absorption enhancing effects were greater on the colonic membrane than on the jejunal membrane. The intestinal membrane toxicity of these enhancers was characterized using the release of cytosolic lactate dehydrogenase from the colonic membrane. A marked increase in the release of lactate dehydrogenase was observed in the presence of sodium deoxycholate and EDTA. The release of lactate dehydrogenase in the presence of these absorption enhancers was similar to that seen with sodium dodecyl sulphate (SDS), used as a positive control, indicating high toxicity of these enhancers to the intestinal membrane. In contrast, sodium glycocholate and sodium caprate caused minor releases of lactate dehydrogenase, similar to control levels, suggesting low toxicity. In addition, the amount of lactate dehydrogenase in the presence of n-lauryl-beta-D-maltopyranoside was much less than that seen with sodium deoxycholate, EDTA and SDS. Therefore, sodium glycocholate, sodium caprate and n-lauryl-beta-D-maltopyranoside are useful absorption enhancers due to their high absorption enhancing effects and low intestinal toxicity. To investigate the absorption enhancing mechanisms of n-lauryl-beta-D-maltopyranoside, the transepithelial electrical resistance (TEER), voltage clamp experiments and the circular dichroism spectra were studied. n-Lauryl-beta-D-maltopyranoside decreased the TEER values in a dose-dependent manner, suggesting that the enhancer may open the tight junctions of the epithelium, thereby increasing the permeability of insulin via a paracellular pathway. This speculation was supported by the findings that 20 mM n-lauryl-beta-D-maltopyranoside produced a greater increase in the paracellular flux rate than in the transcellular flux rate by the voltage clamp studies. Evaluating the circular dichroism spectra we found that insulin oligomers were not dissociated to monomers by the addition of n-lauryl-beta-D-maltopyranoside, but dissociation did occur with the addition of sodium glycocholate. Thus, the dissociation of insulin was not a major factor in the absorption enhancing effect of n-lauryl-beta-D-maltopyranoside. These findings provide basic information to select the optimal enhancer for the intestinal delivery of peptide and protein drugs including insulin.

Algorithms↗
PubMed1999

Responses of Mentha suspension-cultured cells to 2,4-dichlorophenoxyacetic acid and accumulation of esterified phenolic acids in their cell walls.

Two distinct types of cell growth of suspension-cultured Mentha were formed when the cells maintained in the medium containing 1000 micrograms l-1 2,4-D were subcultured into different 2,4-D concentrations. Few cell elongation of Mentha (average cell length: 34-40 microns) was observed after division in the medium containing 1-200 micrograms l-1 2,4-D; and significant cell elongation (average cell length: 95-130 microns) was observed after cell division in the medium containing 500-2000 micrograms l-1 2,4-D. A close correlation between culture medium and water content in the cells indicated that 2,4-D promoted cell elongation by water uptake. Amounts of phenolic acid in cell walls were much higher in unelongated cell walls than in elongated ones during the cultivation, and there was a close correlation between the amounts and the level of PAL activity in elongated and unelongated cells. However, there was no significant difference in cell wall components and its neutral sugar composition between elongated and unelongated cells.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1999

Graphical comparison of coronary arterial culprit lesions in acute myocardial infarction and unstable angina pectoris.

OBJECTIVE: The culprit lesion morphology at acute myocardial infarction (AMI) and unstable angina pectoris (UAP) was investigated by observing the responsible vessels through intravascular ultrasound (IVUS) during the acute stage. METHODS: As the subjects of study, 54 lesions of 54 ACS patients (26 in AMI patients, 28 in UAP patients) were enrolled prospectively from June 1994 to June 1998. The appearance of plaque in the lesion, the distal and proximal sites, extent of calcification, eccentricity, remodeling and shrinkage were observed through IVUS before the intervention. RESULTS: At lesion and distal site, significantly more soft plaques were observed in AMI than UAP. As to the extent of calcification in the former, mild calcification was noted significantly more in distal site as well as a tendency of more mild calcification in the lesion and proximal site. CONCLUSION: These results suggested that the condition of responsible coronary artery is involved in the onset mechanism of AMI and UAP.

Adult↗
PubMed1999

[The usefulness of tracheostomy in Duchenne muscular dystrophy ventilated by a chest respirator].

The respiratory dysfunction in Duchenne muscular dystrophy (DMD) patients increases with age. We have attempted various methods of artificial respiration for them. Recently, a non-invasive positive pressure ventilation (NIPPV) became the first choice of respiration, but the chest respirator (CR) was still one of the choices. In our hospital, DMD patients with tracheostomy wearing a CR were alive for longer period, despite of respiratory dysfunction and complications. We studied 6 DMD patients with CR to evaluate nocturnal hypoxia index (NHI) by examining nocturnal periodic hypoxia, and measured oxygen saturation after 20 mg of clomipramine hydrochloride administration before sleep. Three patients had periodic nocturnal hypoxia which was prevented by the clomipramine administration. Two patients with tracheostomy did not exhibit hypoxia. We speculated that pharyngeal hypotonia during REM sleep induces periodic nocturnal hypoxia, therefore the tracheostomy would prevent hypoxia. Next, we examined the pharyngeal MRI on one DMD patient at the same disease stage who also had night NIPPV. We found that his soft palate and tongue shifted downward, which narrowed his pharynx during REM sleep. Consequently we have concluded that noctunnal periodic hypoxia is mainly caured by obstructive sleep apnea. For DMD patients with CR, the tracheostomy may be effective to prevent hypoxia during sleep.

Adult↗
PubMed1999

The pathogenesis of Kawasaki disease and superantigens.

Kawasaki disease (KD) is an acute febrile illness in infants and children with systemic clinical symptoms, including coronary artery aneurysms. Findings seen in KD patients such as infiltration of T cells into vascular lesions, elevation of soluble interleukin 2 receptors in serum, an imbalance of T cell subsets, and transient depletion of T cells with CD11/CD18 suggest that the activation of T cells is involved in the pathogenesis of KD. In 1992, an interesting mechanism was proposed in which T cell activation by a certain superantigen is involved in the pathogenesis of KD. Examinations have been undertaken extensively to confirm the proposed hypothesis. We, however, still do not have reliable evidence supporting the above hypothesis. In the present paper we review the research papers which support or rule out the view described above. In addition, we discuss the relation between KD and systemic Yersinia pseudotuberculosis infection that manifests clinical symptoms quite similar to those in KD.

Bacterial Toxins↗
PubMed1999

Comparative study of vanadate- and phorbol ester-induced cyclo-oxygenase-2 expression in human endothelial cells.

Our previous study showed that vanadate, an inhibitor of protein tyrosine phosphatases, induced the expression of cyclo-oxygenase (COX)-2 in a protein-tyrosine-kinase (PTK)-dependent manner in human umbilical vein endothelial cells (HUVEC). Here, we further compared the actions of vanadate and phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), on induction of COX-2 with special reference to mitogen-activated protein kinases (MAPKs) in HUVEC. Vanadate induced activation of three families of MAPKs, extracellular signal-regulated kinases 1 and 2 (ERK1/2), p38, and c-Jun amino-terminal kinase (JNK) 1, while activation of ERK 1/2 alone was induced by PMA. The former activation by vanadate and the latter one by PMA were inhibited by tyrphostin-47, an inhibitor of PTKs, and by Ro31-8220, a PKC inhibitor, respectively. Either tyrphostin-47, PD98059, a specific inhibitor of the upstream kinase toward ERK1/2, or SB203580, a specific inhibitor of p38, completely suppressed vanadate-induction of COX-2 mRNA and protein. On the other hand, PMA-induction of COX-2 mRNA and protein was abolished by Ro31-8220 or PD98059 but not by SB203580. These data indicate that PMA-induced and PKC-dependent expression of COX-2 requires mainly activation of ERK 1/2 among MAPKs, while activation of both ERK1/2 and p38 or possibly of all three families of MAPKs is necessary for vanadate-induced and PTK-dependent expression of COX-2.

Cyclooxygenase 2↗
PubMed1999

[Blast crisis of chronic myelocytic leukemia that was difficult to differentiate from Ph+ acute lymphoblastic leukemia].

We encountered a 44-year-old woman with suspected chronic myelocytic leukemia (CML) in the acute phase that was difficult to be differentiate from Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). At disease onset, her bone marrow showed an increase in blasts that were negative for myeloperoxydase (MPO) and Positive for CD10, 19, 34, and HLA.DR. Standard type Ph was detected by chromosome analysis, and both major and minor BCR/ABL m-RNA were detected by reverse-transcriptase polymerase chain reaction (RT-PCR) methods. Neutrophil alkaliphosphatase (NAP) score was normal, and neither eosinophilia nor basophilia was observed in peripheral blood. Under a presumptive diagnosis of Ph-positive ALL (L2), the patient was given AdVP (doxorubicin, vincristine, and prednisolone) therapy followed by a regimen of LMVP (L-asparaginase, mitoxantrone, and VP), and obtained a complete remission 2 months later. At that time, FISH analyses of her bone marrow and blood cells no longer detected bone marrow Ph or BCR/ABL fusion gene. A month later, however, the leukemia relapsed with an increase in MPO-positive blasts in bone marrow, and the patient died soon thereafter. We finally concluded that her leukemia was not Ph-positive ALL, but CML in the acute phase at disease onset.

Adult↗