Biomedical subjects

M Matsubara

Publications and source records attributed to M Matsubara.

At least 109 records · Page 6Linked to original sources

PubMed1996

Syntheses of triglycosyl tetrapeptides and a hexaglycosyl tetrapeptide.

A stereo-controlled synthesis of the model compound for the phytoalexin elicitor-active glycoprotein is described. Glycosylation of the trisaccharide, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl-(1-->6)-2,3,4-tri-O-acetyl- alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-acetyl-alpha-D-mannopyranosyl trichloroacetimidate (12), with N-(9-fluorenylmethoxycarbonyl)-L-seryl-L- proline benzyl ester (3) or N-(carbobenzoxy)-L-seryl-L-proline methyl ester (4) by use of BF3. OEt2 gave the triglycosyl-seryl-proline derivatives. The N- as well as C-terminus of these triglycosyl dipeptides could be deblocked selectively to give compounds 14 and 16, which are versatile intermediates for the completion of model compound synthesis of glycopeptide. Triglycosyl tetrapeptides (18, 21) and hexaglycosyl tetrapeptide (23) have been prepared by the convergent block synthesis.

Amino Acid Sequence↗

PubMed1996

Paraquat causes S-phase arrest of rat liver and lung cells in vivo.

We examined the in vivo effect of paraquat on the cell cycle in rat liver and lung tissues and the protective effect of tungsten (a xanthine oxidase inhibitor) on paraquat toxicity. The bromodeoxyuridine/propidium iodide double-staining method and flow cytometry were used for cell cycle assessment. Wistar rats were fed a standard diet or a tungsten-enriched diet were injected intravenously with 20 mg/kg paraquat, while uninjected rats served as controls. At 1, 3, and 5 days after paraquat injection, the liver and lungs were removed for examination following in vivo labeling with 20 mg/kg bromodeoxyuridine for 1 h. Liver and lung cells were isolated and incubated with an anti-bromodeoxyuridine antibody and with propidium iodide for DNA staining. Flow cytometry showed that the S-phase cell populations in the liver and lungs of paraquat-injected rats fed a standard diet were increased markedly on days 1 and 3 after injection compared with the control levels. However, on day 5 the liver cells had nearly returned to normal, while the S-phase population remained high in the lungs. In contrast, the S-phase cell populations of liver and lung tissue showed no increase after paraquat injection in rats fed a tungsten-enriched diet. These findings suggest that paraquat-induced cytotoxicity is more prolonged in the lungs than in the liver. In addition, paraquat toxicity appears to be mediated by xanthine oxidase and xanthine oxidase inhibitors may be useful an an antidote.

Animals↗

PubMed1996

Topographic analyses of somatosensory evoked potentials following stimulation of tibial, sural and lateral femoral cutaneous nerves.

Using topographic maps, we studied the scalp field distribution of somatosensory evoked potentials (SEPs) in response to the stimulation of the tibial (TN), sural (SN) and lateral femoral cutaneous (LFCN) nerves in 24 normal volunteers. Cortical peaks, i.e., N35, P40, N50 and P60 were generally dominant in the contralateral hemisphere for the LFCN-SEP, whereas all peaks except N35 had dominance in the ipsilateral hemisphere to TN- and SN-SEPs. The findings imply that ipsilateral or contralateral peak dominance for the lower extremity SEP is determined by where the cortical leg representation occurs. As a result, mesial hemisphere representation results in peak dominance projected to the hemisphere ipsilateral to stimulation. Representations at the superior lip of the interhemispheric fissure or lateral convexity lead to midline or contralateral peak dominance. These findings also suggest that the paradoxically lateralized P40 is not the result of a positive field dipole shadow generated by the primary negative wave in the mesial hemisphere, but is the primary positive wave, analogous to P26 of the median nerve SEP. Accordingly, contralaterally dominant N35 is likely equivalent to the first cortical potential of N20 in the median nerve SEP. The difference in vector directions of potential fields between N35 and P40 may account for the opposite hemispheric dominance for these peaks in TN- and SN-SEPs.

Adult↗

PubMed1996

Magnetic resonance imaging of neurogenic tumors of the thoracic inlet: determination of the parent nerve.

To investigate the value of magnetic resonance imaging (MRI) in determining the parent nerves of neurogenic tumors in the thoracic inlet, analysis of MR images was performed in nine patients with surgically resected neurogenic tumors in the thoracic inlet (two neurofibromas and one schwannoma of the vagus nerve, three schwannomas of the brachial plexus, and two schwannomas and one ganglioneuroma of the sympathetic nerves). These MR images were compared with surgical and pathologic findings. The multidirectional capability and excellent tissue contrast of MRI facilitated recognition of the location, shape, and extent of the tumors. MRI, which permitted an easy understanding of the spatial relation between the tumors and the subclavian vessels, scalenus muscles, and brachial plexus, was useful in determining the nerves of origin. Two neurofibromas, four of six schwannomas, and one ganglioneuroma were recognized to extend along the axes of the parent nerves on MR images. MRI is useful in determining the parent nerve of neurogenic tumors in the thoracic inlet and is helpful in planning surgical treatment of these tumors.

Brachial Plexus↗

PubMed1996

Characterization of manganese peroxidases from the hyperlignolytic fungus IZU-154.

Four isozymes of manganese peroxidase (MnP) were identified in the culture fluid of the hyperlignolytic fungus IZU-154 under nitrogen starvation conditions. One of them was purified and characterized kinetically. The specific activity and Kcat/K(m) value of the MnP from IZU-154 were 1.6 times higher than those of the MnP from a typical lignin-degrading fungus, Phanerochaete chrysosporium. Two cDNAs encoding MnP isozymes from IZU-154 were isolated. The coding sequence of the two cDNAs, IZ-MnP1 cDNA and IZ-MnP2 cDNA, were 1,152 (384 amino acids) and 1,155 (385 amino acids) bp in length, respectively. They exhibit 96.2% identity at the nucleotide level and 95.1% identity at the amino acid level. Southern blot analysis indicated that two MnP isozyme genes exist in IZU-154 genomic DNA. The primary structures of two MnPs from IZU-154 were similar to those of MnPs from P. chrysosporium. The amino acid sequences including the important residues identified in MnPs from P. chrysosporium, such as the manganese-binding residues, the calcium-binding residues, the disulfide bonds, and the N-glycosylation site, were conserved in the two deduced IZ-MnPs. However, several discrepancies were found in the context around the distal histidine residue between MnP from IZU-154 and MnP from P. chrysosporium, which likely led to the difference in the kinetic parameters for MnP function.

Amino Acid Sequence↗

PubMed1996

[Relationship between diaphragm weight and body composition].

To study the relationship between diaphragm weight and body composition, we measured fat body mass and lean body mass by dual-energy X-ray absorptiometry (XR-26, Norland), and weighed the diaphragms of patients at autopsy. The subjects were 22 patients with various diseases (13 men and 9 women, aged 72.6 +/- 9.5 years). In 8 of the patients, respiratory muscle strength was assessed with maximal pressure at the mouth. The diaphragm weight was 185.2 +/- 58.2 g and it correlated significantly with lean body mass (r = 0.77, r = 0.73, p < 0.01). Maximal inspiratory pressure at TLC correlated significantly with diaphragm weight. These results show that respiratory muscle strength is related to diaphragm weight and that analysis of body composition may be useful in assessing changes in the mass of the diaphragm.

Absorptiometry, Photon↗

PubMed1996

Role of matrix metalloproteinases in failure to re-epithelialize after corneal injury.

Delayed re-epithelialization of the cornea after injury usually precedes stromal ulceration. Previous findings using a rat thermal injury model suggested that re-epithelialization is impeded by products of resident corneal cells, which destroy adhesive structures at the basement membrane zone. In this study, we provide additional evidence for this concept. Failure to re-epithelialize was found to correlate with an increase in the amounts of gelatinolytic matrix metalloproteinases present in the rat cornea. One of these gelatinases, gelatinase B, is synthesized by the resident corneal cells, and inhibitions of its synthesis correlated with inhibition of basement membrane dissolution. The matrix metalloproteinases collagenase and stromelysin are also synthesized by resident corneal cells in thermally injured corneas of rabbits, but the timing of bulk enzyme synthesis correlated more closely with deposition of repair tissue in the stroma than with failure to re-epithelialize. Nevertheless, in human corneas with repair defects, gelatinase B and collagenase are synthesized by cells in the basal layer of the epithelium directly adjacent to the basement membrane, suggesting that both could participate in dissolution of this structure. Importantly, treatment of thermally injured corneas with a synthetic inhibitor of matrix metalloproteinases significantly improved basement membrane integrity. These data support the concept that over-expression of matrix metalloproteinases by resident corneal cells impedes re-epithelialization after some types of corneal injury.

Animals↗

PubMed1996

[Sjögren's syndrome complicated by thymoma].

A 43-year-old woman with a history of Sjögren's syndrome was admitted to our hospital because of dyspnea due to anemia. Her chest X ray film on admission revealed an anterior mediastinal tumor. We diagnosed this tumor as a thymoma based on a chest CT scan and magnetic resonance imaging. Because the latter indicated that the thymoma may have involved the mediastinal great vessels, preoperative chemotherapy with cisplatin, doxorubicin hydrochloride, vincristine sulfate and cyclophosphamide. Thereafter the tumor was successfully resected along with part of the right pleura. Thymoma as a complication of Sjögren's syndrome is rare. Here we also discuss the treatment of thymoma and the combination of these two diseases.

Adult↗

PubMed1995

Lipoxygenase product formation and cell adhesion during neutrophil-glomerular endothelial cell interaction.

Leukotriene (LT) and lipoxin (LX) levels were monitored in ionophore-stimulated coincubations of polymorphonuclear neutrophils (PMN) and microvascular kidney glomerular endothelial cells (GEN) to determine the profile of lipoxygenase (LO) products generated during cell-cell interactions and the relative contributions of transcellular pathways to LO product biosynthesis in this setting. LTB4 and LTC4 were the major products formed, as determined by reverse-phase high-performance liquid chromatography and radioimmunoassay. LTB4 and LTC4 levels were increased by 23 and 185%, respectively, in coincubations of PMN and GEN, compared with incubations of PMN alone. In contrast, LXA4 and LXB4 levels were not changed in the presence of GEN. These data suggested that GEN utilize PMN-derived LTA4 to generate LT. In keeping with this hypothesis, LT biosynthesis was enhanced if PMN were primed with human granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine that augments LTA4 biosynthesis by activated PMN. The influence of LT on PMN adhesion to GEN was also assessed, since adhesion appears to be a pivotal event in recruitment of PMN in acute glomerulonephritis. Under basal conditions, LTB4 provoked low levels of adhesion via a PMN-directed CD11/CD18-dependent mechanism. The level of adhesion was markedly enhanced by prior priming of PMN with GM-CSF or activation of GEN with tumor necrosis factor-alpha (TNF). LTB4 was as potent in this regard as the complement component C5a, platelet-activating factor (PAF), and interleukin-8 (IL-8), other mediators that contribute to the entrapment of PMN in inflamed glomeruli. LTC4 also provoked PMN-GEN adhesion via a CD11/CD18-dependent mechanism, but, in contrast to LTB4, via actions with GEN. This action of LTC4 appeared to be mediated, at least in part, by induction of PAF synthesis by GEN. Interestingly, LT-induced PMN-GEN adhesion was markedly attenuated following remodeling of PMN phospholipids with 15(S)-hydroxyeicosatetraenoic acid, a product of 15-LO, which has been implicated as an anti-inflammatory eicosanoid in some experimental and human inflammatory diseases. Taken together, these results provide further evidence that 1) transcellular biosynthetic pathways may amplify the profiles of inflammatory mediators and thereby contribute to leukocyte recruitment in acute glomerulonephritis and 2) that products of the 5-LO and 15-LO pathways may exert opposing actions on PMN trafficking during glomerular inflammation in vivo.

Amino Acid Sequence↗

PubMed1995

Dissociated changes of frontal and parietal somatosensory evoked potentials in sleep.

We studied the changes of frontal and parietal somatosensory evoked potentials (SEPs) in the awake state versus different stages of sleep in 10 normal adult subjects. Frontal and parietal SEP components were affected differentially as sleep stages progressed. In general, the amplitudes of frontal components, notably P22, were increased in sleep, whereas the amplitudes of parietal components were decreased in sleep. A sensitive waveform change from the awake state to sleep was present in the frontal response, where a subtle notched negativity, termed "N40," was present only in the awake state and quickly dissipated in all stages of sleep, including stage 1. The amplitude changes from the awake state to stage 3/4 sleep were neither linear nor parallel among SEP components. The most discordant changes occurred in stage 3/4. The amplitudes for the frontal N18-P22-N30 complex and parietal N20-P26-N32 complex increased from stage 2 to stage 3/4, while those for frontal N30-fP40 and parietal N32-pP40 decreased. In contrast to these divergent amplitude changes, the latencies of all components except P14 and frontal N18 showed progressive prolongation from the awake state to slow-wave sleep. The SEP waveforms and latencies in REM sleep approximated those in the awake state, although amplitudes for frontal peaks still remained slightly higher and amplitudes for parietal peaks slightly lower. We postulate that interactions of excitatory and inhibitory phenomena are responsible for the component-dependent and sleep-stage-dependent amplitude enhancement or depression in sleep.

Adult↗

PubMed1995

Preparation of characteristic diagram for refolding of lysozyme.

The characteristic diagram for refolding of denatured reduced lysozyme was prepared in terms of recovered activity by employing urea and LiCl concentrations as two axes of rectangular coordinates. The diagram obtained will serve as a new tool not only for the optimum design of refolding media but also for the study of the refolding mechanism.

Animals↗

PubMed1995

Retroperitoneal approach for lumbar lateral meningocele--case report.

A 29-year-old female with neurofibromatosis presented with a right lumbar lateral meningocele. Abdominal computed tomography (CT) showed a huge right retroperitoneal cyst expanding anterolaterally and displacing the right kidney. CT following myelography disclosed the cyst expanding through a wide defect of the right pedicles of the T-12 and L-1 vertebrae. The cyst was resected through a retroperitoneal approach with right flank oblique incision. Postoperatively, cerebrospinal fluid leakage occurred, which improved after lumboperitoneal shunt. Careful screening for lateral meningocele, including the lumbar region, should be undertaken in a patient with neurofibromatosis who presents with vertebral anomalies.

Adult↗

PubMed1995

[Value of serum PSA and PAP measurement with newly developed latex turbidimetric immunoassay].

Serum prostate specific antigen (PSA) and prostatic acid-phosphatase (PAP) levels in normal controls, and patients with prostate cancer, benign prostate hypertrophy (BPH) and other urological diseases were examined with a newly developed latex turbidimetric immunoassay (LPIA ACE PSA, LPIA ACE PAP, IATRON LABORATORIES, INC., Tokyo, Japan). The advantageous characteristics of this method are small amount (10 microliters) of serum required and short time (about 20 min.) for performing this assay. There was a high linear correlation between LPIA ACE PSA and MARKIT-F PA (r2 = 0.953), between LPIA ACE PSA and TANDEM-E PSA (r2 = 0.881) and between LPIA ACE PAP and ABBOTT-PAP EIA (r2 = 0.946). When the BPH patients (n = 110) were used as negative controls, the cut-off value of PSA was determined to be 4.3 ng/ml. Using this level as the cut-off value, the sensitivity was 78% (42 positive/54 untreated prostate cancer patients), specificity (negative rate in BPH patients) was 95% and efficiency was 89%. In a follow-up study of prostate cancer, the PSA value was elevated above the cut-off value in 68% at the time of clinical progression. These findings suggest that LPIA ACE PSA is a useful tool for serum PSA measurement. The cut-off value of PAP measured with LPIA ACE PAP was 9.0 ng/ml, which was determined by the same method as PSA. The sensitivity, specificity and efficiency ware 39%, 96% and 77%, respectively. These findings indicate that PAP is less useful than PSA in the diagnosis of prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗

PubMed1995

Unique regulation of the matrix metalloproteinase, gelatinase B.

PURPOSE: The matrix metalloproteinase (MMP), gelatinase B, is expressed by both corneal cell types found at the epithelial-stromal tissue interface, the site of basement membrane repair in the healing cornea. This study investigates the relative regulation of gelatinase B compared to other MMPs in response to agents related to those found in the corneal repair environment or in corneal ulcers. METHODS: A culture model of corneal cells isolated from rabbit was used. RESULTS: Gelatinase B is the major MMP expressed by corneal epithelial cells, whereas stromal fibroblasts produce gelatinase B along with three other MMPs: collagenase, stromelysin, and gelatinase A. Phorbol-12-myristate 13-acetate (PMA) stimulates gelatinase B mRNA and protein synthesis by corneal cells, which is similar to its effect on the other MMPs. Stimulation occurs, at least partially, at the transcriptional level. PMA-stimulated MMP expression follows biphasic kinetics, with the major effect on collagenase, stromelysin, and gelatinase A occurring during the late component. In contrast, the major gelatinase B response occurs during the early component. Transforming growth factor-beta (TGF-beta) has no effect on constitutive expression of gelatinase B by fibroblasts; however, expression stimulated by PMA is enhanced. In contrast, constitutive expression of collagenase and stromelysin is inhibited by TGF-beta. However, in the presence of PMA, the initial inhibitory effect of TGF-beta is reversed after treatment. CONCLUSION: Gelatinase B expression is regulated differently from other corneal MMPs. This provides a mechanism for control of basement membrane repair independent of repair processes in the stroma.

Animals↗

PubMed1994

The rabbit gene for 92-kDa matrix metalloproteinase. Role of AP1 and AP2 in cell type-specific transcription.

We isolated the rabbit gene for the 92-kDa matrix metalloproteinase, gelatinase B, and sequenced 1802 contiguous bases covering the first three exons and 522 bases of DNA upstream of the start site for transcription. The DNA between bases -519 and +19 is sufficient to drive expression of a reporter gene in early passage cultures of corneal fibroblasts or primary cultures of corneal epithelial cells. Basal activity of the gelatinase B promoter in fibroblasts is lower than a collagenase promotor of 1800 base pairs, but activity of both promotors is similarly stimulated by treatment of transfected cells with phorbol 12-myristate 13-acetate, and stimulation is enhanced by co-treatment with transforming growth factor-beta. In contrast, basal activity of the gelatinase B promotor in epithelial cells is higher than the collagenase promotor. Deletion analysis demonstrated that sequences upstream of base -330 confer cell type-specific activity to the gelatinase B promotor. Site-directed mutagenesis revealed that an AP1-like element within this region is specifically utilized by fibroblasts. This region also contains elements that confer the capacity for activation by AP2, a transcription factor found to be expressed by corneal epithelial cells but not by corneal fibroblasts. In contrast, AP2 does not activate the collagenase promotor. These results provide a molecular basis for the unique cell type-specific expression pattern of gelatinase B as compared to other matrix metalloproteinases.

Animals↗

PubMed1994

Renaturation of the mature subtilisin BPN' immobilized on agarose beads.

We report here another example of renaturation of subtilisin BPN'(Sbtl) by using an immobilized preparation instead of applying a digestible mutant of Streptomyces subtilisin inhibitor (SSI), a proteinaceous inhibitor of Sbtl [M. Matsubara et al. (1994) FEBS Letters 342, 193-196]. The mature Sbtl was immobilized on agarose beads employing the amino group of the protein. After thorough washing, the immobilized Sbtl was subjected to denaturation in 6 M guanidine hydrochloride (GdnHCl) at pH 2.4 for 4 h, followed by renaturation in 2 M potassium acetate at pH 6.5 for 24 h. This denaturation/renaturation cycle was repeated five times. The recovered activity of the renatured immobilized Sbtl settled at a constant level after the third denaturation/renaturation cycle, demonstrating that almost 100% renaturation was attained by use of the immobilized Sbtl. This immobilized Sbtl preparation could well be utilized for the mechanistic study of protein folding. We then found that 2 M potassium acetate was superior to 2 M potassium chloride as a refolding medium and that the ability of SSI to induce the correct shape of the mature Sbtl was lacking in several refolding media in both thermodynamic and kinetic criteria. Thus the main cause for the increase of refolding yield of Sbtl by coexistence of SSI was prevention of the autolysis of Sbtl.

Amino Acid Sequence↗

PubMed1994

Achievement of renaturation of subtilisin BPN' by a novel procedure using organic salts and a digestible mutant of Streptomyces subtilisin inhibitor.

The pro-sequences of proteases have been considered to be required for the refolding of denatured proteases. However, here we report achievement of almost complete restoration of enzymatic activity of subtilisin BPN' in the absence of its pro-sequence. The presence of 2 M potassium acetate in the folding medium enhanced the refolding efficiency of guanidine hydrochloride (GdnHCl)-denatured subtilisin BPN' by up to 28%, and other organic salts were also found to be useful, suggesting that general contribution of the bulky hydrophobic moieties of the salts to the formation of a favorable environment required for folding. This finding will provide new insights into the folding mechanisms not only of proteases but also of various other proteins. Almost complete restoration of enzymatic activity of denatured subtilisin in the organic salt solution was accomplished by further addition of mutated Streptomyces subtilisin inhibitor (SSI), which had been converted to a digestible temporary inhibitor by removal of the disulfide bridge near the reactive site.

Acetates↗

PubMed1994

Synthesis of a glycopeptide with phytoalexin elicitor activity. I. Synthesis of a triglycosyl L-serine and a triglycosyl L-seryl-L-proline dipeptide.

A stereocontrolled synthesis of the model compound for the phytoalexin elicitor-active glycoprotein is described. Glycosylation of the disaccharide, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl-(1-->6)-2,3,4-tri-O-acetyl- alpha- D-mannopyranosyl trichloroacetimidate, with N-(carbobenzoxy)-(2,3,4-tri-O-acetyl-alpha-D-mannopyranosyl)-(1-->3)-L- serine methyl ester or N-(carbobenzoxy)-(2,3,4-tri-O-acetyl-alpha-D-mannopyranosyl)-(1-->3)-L- seryl-L- proline methyl ester by use of AgOTf gave the desired trisaccharide-serine or trisaccharide-seryl-proline derivatives, which were transformed into beta-D-glucopyranosyl-(1-->6)-alpha-D-mannopyranosyl-(1-->6)-alpha-D- mannopyranosyl-(1-->3)-L-serine and triglycosyl-(1-->3)-L-seryl-L-proline via removal of the N-carbobenzoxy group, followed by deacylation.

Carbohydrate Conformation↗