Biomedical subjects

T Matsunaga

Publications and source records attributed to T Matsunaga.

At least 19 recordsLinked to original sources

PubMed1999

The plant cell wall polysaccharide rhamnogalacturonan II self-assembles into a covalently cross-linked dimer.

The location of the 1:2 borate-diol ester cross-link in the dimer of the plant cell wall polysaccharide rhamnogalacturonan II (RG-II) has been determined. The ester cross-links the apiofuranosyl residue of the 2-O-methyl-D-xylose-containing side chains in each of the subunits of the dimer. The apiofuranosyl residue in each of the two aceric acid-containing side chains is not esterified. The site of borate esterification is identical in naturally occurring and in in vitro synthesized dimer. Pb2+, La3+, and Ca2+ increase dimer formation in vitro in a concentration- and pH-dependent manner. Pb2+ is the most effective cation. The dimer accounts for 55% of the RG-II when the monomer (0.5 mM) is treated for 5 min at pH 3.5 with boric acid (1 mM) and Pb2+ (0.5 mM); at pH 5 the rate of conversion is somewhat slower. Hg2+ does not increase the rate of dimer formation. A cation's charge density and its ability to form a coordination complex with RG-II, in addition to steric factors, may regulate the rate and stability of dimer formation in vitro. Our data provide evidence that the structure of RG-II itself determines which apiofuranosyl residues are esterified with borate and that in the presence of boric acid and certain cations, two RG-II monomers self-assemble to form a dimer.

Boric Acids↗

PubMed1999

Automated detection of anti-double-stranded DNA antibody in systemic lupus erythematosus serum by flow immunoassay.

We describe a novel automated flow immunoassay system for quantification of anti-double-stranded (ds) DNA autoimmune antibodies in the serum of patients suffering from systemic lupus erythematosus. dsDNA (360 bp) was covalently coupled with alkaline phosphatase (ALP) to form a novel analytical reagent (ALP-DNA). After immunoreaction, antibody-antigen complexes between ALP-DNA and anti-dsDNA monoclonal antibody were separated from unreacted ALP-DNA by an ion-exchange column on the basis of the difference in isoelectric point. Antibody-antigen complexes were subsequently quantified by luminescence following addition of 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl- 1,2-dioxetane. The assay yielded a linear relationship between signal and concentration of anti-dsDNA monoclonal antibody in the range of 0-300 micrograms/mL. This simple technique permits the assay of anti-dsDNA autoimmune antibodies within 25 min. The ion-exchange column was simply regenerated by occasional elution with eluent (20 mM N-methylpiperazine, pH 5.5) supplemented with 0.5 M NaCl, to remove unreacted ALP-DNA.

Antibodies, Antinuclear↗

PubMed1999

Recognition of Amphiphiles with Many Pendent Galactose Residues by Ricinus communis Agglutinin.

Amphiphiles which carry many pendent galactose residues as side chains were prepared by telomerization of 2-methacryloyloxyethyl beta-D-galactopyranoside (MEGal) or 3-(2-methacryloyl aminoethylthio)propyl D-galactopyranoside (MEPGal, alpha:beta = 3.9:1) using a lipophilic radical initiator. The galactose-carrying amphiphiles (DP (degree of polymerization) = 15) incorporated in liposomes were recognized by a lectin from Ricinus communis (RCA120), which was proven by the increase in turbidity of the liposome suspension after mixing with the lectin. The recognition was largely affected by the distance between the galactose residues and the polymer main chain, and the surface density of the amphiphile in the liposomes. The liposomes containing these galactolipids were not taken up by mouse peritoneal macrophages, probably due to a steric hindrance of polymer main chains from the uptake of D-galactose receptors on the macrophages. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Hybrid functional electrical stimulation for energy-efficient restoration of standing-up motion.

OBJECTIVE: To find the most energy-efficient standing-up motion for quadriceps and to restore that motion in a person with complete paraplegia by using hybrid functional electrical stimulation. DESIGN: Nonrandomized control trial. SETTING: A referral center and institutional practice providing outpatient care. PARTICIPANTS: Twenty-nine volunteer samples were used to collect normal data. One patient with complete paraplegia received treatment for the restoration of standing-up motion. MAIN OUTCOME MEASUREMENTS: Joint angles and ground reaction forces were investigated during the standing-up motion with arms crossed in front of the chest with an ankle-foot orthosis set at various angles. The electromyogram (EMG) was performed during the standing-up motion with and without the orthosis. The energy costs of quadriceps during the standing-up motion were calculated using a mathematical model. Standing-up motion in a person with complete paraplegia was restored and then analyzed by measuring the vertical ground reaction force and the hip and knee angles. RESULTS: Quadriceps energy cost was lowest (p < .05) in subjects wearing the ankle-foot orthosis set at neutral with a flat sole line. In the integrated EMG the peak value of rectus femoris contraction was larger with the orthosis than without it (p < .05). A patient with complete paraplegia was able to stand up smoothly from a wheelchair based on stimulation patterns obtained from healthy subjects. CONCLUSIONS: Energy-efficient standing-up motion in a patient with complete paraplegia was restored when the patient used an ankle-foot orthosis set at neutral with a flat sole line.

Adult↗

PubMed1999

Muscle fatigue from intermittent stimulation with low and high frequency electrical pulses.

OBJECTIVE: To evaluate muscle fatigue resulting from intermittent low frequency and high frequency stimulation for the application of closed-loop control in functional electrical stimulation (FES). DESIGN: Nonrandomized trial. SETTING: General community, a referral center, institutional practice, and ambulatory care. PATIENTS: Twenty healthy nondisabled men volunteered for the normal muscle group. Four paraplegic men with implanted percutaneous intramuscular electrodes for FES volunteered for the paralyzed muscle group. INTERVENTION: The stimulation frequency was set at low (20 Hz) or high (100 Hz). Stimulation was administered in 4-second bursts at the start of 60-second, 120-second, and 240-second periods (duty cycles of 1/15, 1/30, and 1/60, respectively). MAIN OUTCOME MEASUREMENTS: Knee extensor torques were measured during intermittent electrical stimulation. A strength decrement index (SDI) was used to assess muscle fatigue. Actual knee extensor torques in the paraplegic men were also measured with an isokinetic dynamometer. RESULTS: Muscle fatigue was significantly greater at 20 Hz than at 100 Hz for both the nondisabled and the paraplegic subjects (p < .0001). Muscle fatigue at the 1/15 cycle was significantly reduced (p < .01). CONCLUSIONS: Muscle fatigue was greater at the lower frequency (20 Hz) than at the higher frequency (100 Hz) during intermittent electrical stimulation, suggesting that intermittent high frequency stimulation may be valuable in the development of closed-loop control strategies for FES.

Adult↗

PubMed1999

Tympanoplasty in a patient with hemophilia B.

We report the case of a 36-year-old hemophilia B who suffered from cholesteatoma and underwent tympanoplasty. Though the factor IX activity was less than 1% of normal before surgery, adequate replacement of factor IX led to the achievement of hemostasis during and after surgery. The cholesteatoma was completely extirpated with matrix, and a type I canal-up tympanoplasty was subsequently performed. Careful preoperative evaluation and close cooperation with the hematologist are required if surgery is to be successful. We also present here the use of continuous administration of monoclonal antibody-purified factor IX concentrate, Christmassin M.

Adult↗

PubMed1999

Postnatal growth failure, short life span, and early onset of cellular senescence and subsequent immortalization in mice lacking the xeroderma pigmentosum group G gene.

The xeroderma pigmentosum group G (XP-G) gene (XPG) encodes a structure-specific DNA endonuclease that functions in nucleotide excision repair (NER). XP-G patients show various symptoms, ranging from mild cutaneous abnormalities to severe dermatological impairments. In some cases, patients exhibit growth failure and life-shortening and neurological dysfunctions, which are characteristics of Cockayne syndrome (CS). The known XPG protein function as the 3' nuclease in NER, however, cannot explain the development of CS in certain XP-G patients. To gain an insight into the functions of the XPG protein, we have generated and examined mice lacking xpg (the mouse counterpart of the human XPG gene) alleles. The xpg-deficient mice exhibited postnatal growth failure and underwent premature death. Since XPA-deficient mice, which are totally defective in NER, do not show such symptoms, our data indicate that XPG performs an additional function(s) besides its role in NER. Our in vitro studies showed that primary embryonic fibroblasts isolated from the xpg-deficient mice underwent premature senescence and exhibited the early onset of immortalization and accumulation of p53.

Animals↗

PubMed1999

Purification of a growth-suppressing factor for bovine artery endothelial cells from mouse lymphoma P388D1 cells.

A growth-suppressing factor for bovine artery endothelial cells (BAEGSF) was purified from the conditioned medium of a mouse lymphoma P388D1 cell culture in the presence of 100 microg/ml carboxymethylated curdlan. The purification steps included, in order, ammonium sulfate fractionation and eight stages of column chromatography on Macro-Prep Ceramic Hydroxyapatite, Q-Sepharose, Sephacryl S-300 HR, Matrex PBA-30, CHT II, Resource-Q, anti-bovine serum albumin (BSA) agarose, and Superdex 200HR columns. The purified BAEGSF showed two bands with silver staining on a sodium dodecyl sulfate polyacrylamide gel under reducing conditions (SDS-PAGE) and their molecular weights were estimated as approximately 55 and 63 kDa, while the molecular weight of the purified BAEGSF was estimated as about 65 kDa by gel filtration using Superdex 200HR. This result shows that BAEGSF obtained from Superdex 200HR chromatography is a partially purified preparation and suggests that one of the two bands on SDS-PAGE corresponds to BAEGSF. BAEGSF was shown not to have a lethal effect on endothelial cells, but had an inhibitory action on the proliferation of these cells. Furthermore, the growth-suppressing activity of BAEGSF for bovine artery endothelial cells (BAE) was not inhibited by anti-transforming growth factor-beta (TGF-beta), anti-tumor necrosis factor-alpha (TNF-alpha), and anti-interleukin-1 (IL-1) antibodies. These results suggest that BAEGSF is different from TGF-beta, TNF-alpha, and IL-1 which have been reported to inhibit BAE growth.

Animals↗

PubMed1999

Effect of salt addition on the fractal structure of aggregates formed by heating dilute BSA solutions.

The fractal dimension, Df, of aggregates in a dilute BSA system with added salt was evaluated by static light scattering (SLS). A fractal structure was observed for the system with NaCl addition. The values of Df increased with increasing heating time and ionic strength. The values of Df were larger than those (Df = 1.8 or 2.1) predicted by the conventional cluster-cluster aggregation model, probably due to a "restructuring" of aggregates during the aggregation process. On the other hand, a fractal structure was not apparent for the system with added CaCl2.

Animals↗

PubMed1999

Use of PCR serum in diagnosing and monitoring cytomegalovirus reactivation in bone marrow transplant recipients.

We previously reported that the use of polymerase chain reaction (PCR) in detecting cytomegalovirus (CMV) DNA in serum (sPCR) enables the detection of CMV viremia, which has not been possible with other methods. In this study, the clinical usefulness of sPCR was investigated by comparison with the results of three other diagnostic methods, i.e., antigenemia assay (AG), shell vial culture test (shell vial), and complement-fixing (CF) antibody titer. The present study included 26 patients with hematological diseases who had undergone allogeneic bone marrow transplantation (BMT). A total of 347 samples were collected, and the results of the sPCR and AG methods were in agreement in 91.1% of the samples. When a subject was positive in both the sPCR and AG tests, and the other two tests (shell vial and CF) were also positive, CMV reactivation was surmised as definite. When only the result of the shell vial test or the CF test was positive, these results were taken as false-positives. The time at which the samples became positive in each of these four tests was 7.5 weeks post-BMT for sPCR, 7.0 weeks post-BMT for the AG test, 7.4 weeks post-BMT for the shell vial test, and 9.7 weeks post-BMT for the CF test. Thus, it was found that samples became positive at almost the same time for the sPCR, AG, and shell vial tests. Interstitial pneumonitis (IP) due to CMV developed in 3 subjects. These cases were positive in the sPCR, AG, and shell vial tests prior to the manifestation of symptoms of IP. The CF test did not become positive until after the onset of the disease. As the IP due to CMV was controlled with treatment, the sPCR and AG tests became negative. With the shell vial and CF tests, on the other hand, the test results continued to be positive even after the IP was cured. These findings demonstrate that the sPCR test method--like the AG test--yields few false-positive results. Therefore, the sPCR method is useful in early diagnosis of reactivation of CMV and for evaluation of the efficacy of therapy administered for IP. In addition, sPCR can be performed simultaneously on a large number of samples, and the evaluation of the test results is simple. We conclude that the sPCR test may be superior to the three other diagnostic methods for evaluation of serum samples from multiple institutions.

Adolescent↗

PubMed1999

[Late phase II clinical study of RP56976 (docetaxel) in patients with advanced/recurrent head and neck cancer].

A late phase II clinical study of RP56976 (docetaxel), a new anticancer agent for advanced/recurrent head and neck cancer, was conducted in 29 institutions all over Japan as a multi-institutional cooperative study. Docetaxel was administered by 1 to 2-hour intravenous infusion at a dose of 60 mg/m2 every 3 to 4 weeks. Of 63 patients eligible in this study, 59 were judged as complete cases. Complete response (CR) was observed in 1 patient, partial response (PR) in 13, no change (NC) in 25, and progressive disease (PD) in 20, for an overall response rate of 22.2% (14/63, 95% CI: 12.7-34.5%) in eligible cases, and 23.7% (14/59, 95% CI: 13.6-36.6%) in complete cases. Previously treated patients showed a 17.9% (10/56) response rate, whereas treatment--naive patients showed a 57.1% (4/7) response rate. Among 46 patients who received prior chemotherapy, one CR and 7 PR were observed with a 17.4% response rate. Major hematological toxicities were leucopenia in 95.1% (> or = grade 3, 59.7%) and neutropenia in 90.3% (> or = grade 3, 79.0%). Other severe toxicities (> or = grade 3) included anorexia in 9.7% (6 cases), diarrhea in 3.2% (2 cases), dyspnea in 3.2% (2 cases), and fatigue in 3.2% (2 cases). One patient had a grade 3 interstitial pneumonia; however, symptoms were resolved by the administration of corticosteroids. During this study, one patient died due to multiple organ failure (MOF) caused by disseminated intravascular coagulation (DIC), and this case was reported as a therapy-related death. Based on these results, docetaxel is an active agent for treatment of head and neck cancer.

Adenocarcinoma↗

PubMed1998

Different ras gene mutational frequencies in thyroid papillary carcinomas in Japan and Thailand.

The incidence and pattern of ras oncogene mutations in human malignancies demonstrate geographic and racial differences. For example, specificity of alterations is found in cholangiocellular carcinomas in Thai patients with a different etiology from those in Japanese patients. In the present study, a comparison of ras gene mutations in thyroid papillary carcinomas from Japanese and Thai patients was performed using single-strand conformation polymorphism and direct sequencing analyses. The incidence of ras mutation differed markedly in Japanese (two of 24 carcinomas, 8.3%) and Thai (five of 10 carcinomas, 50%) patients. In addition, all but one ras mutation occurred at codon 12 of the K-ras gene in the Thai cases. These results suggest that thyroid cancers in Thailand may be due to specific genetic and/or environmental factors.

Adult↗

PubMed1998

Effects of pilsicainide and propafenone on vagally induced atrial fibrillation: role of suppressant effect in conductivity.

The effects of pilsicainide on vagally induced atrial fibrillation and on electrophysiological parameters were compared with those of propafenone in alpha-chloralose-anesthetized dogs. Conduction velocity, effective refractory period, wavelength, averaged atrial fibrillation cycle length and activation sequence in the right atrial free wall were determined before and after drug administration. Pilsicainide (2 mg/kg/5 min and 3 mg/kg/h)(n=10) or propafenone (2 mg/kg/15 min and 4 mg/kg/h)(n=10) was intravenously infused during stable atrial fibrillation sustaining > 30 min. Pilsicainide terminated atrial fibrillation in nine dogs, while propafenone did so in three (p < 0.01). After the drug, conduction velocity was suppressed more in the pilsicainide than in the propafenone group(p < 0.01). There was no difference in effective refractory period after drug between the two groups. Mean wavelength was prolonged from 46.0 to 70.4 mm in the pilsicainide group and from 45.0 to 110.8 mm in the propafenone (p < 0.01 vs. pilsicainide). Activation mapping during atrial fibrillation showed Type II or III atrial fibrillation as previously defined [Konings, K.T.S., Kirchhof, C.J.H.J., Smeets, J.R.L.M., Wellens, H.J.J., Penn, O.C., Allessie, M.A., 1994. High-density mapping of electrically induced atrial fibrillation in humans. Circulation. Vol. 89, pp. 511-521.] before the drug, and changed to Type I before atrial fibrillation termination. Thus, pilsicainide was more effective to terminate vagally induced atrial fibrillation than was propafenone despite a greater effect of propafenone than of pilsicainide on wavelength. In this canine atrial fibrillation model, the suppression of conduction velocity may play an important role in changing the activation pattern of atrial fibrillation and thus, terminating atrial fibrillation.

Animals↗

PubMed1998

Prevention of marine biofouling using a conductive paint electrode

Conductive paint electrode was used for marine biofouling on fishing nets by electrochemical disinfection. When a potential of 1.2 V vs. a saturated calomel electrode (SCE) was applied to the conductive paint electrode, Vibrio alginolyticus cells attached on the electrode were completely killed. By applying a negative potential, the attached cells were removed from the surface of the electrode. Changes in pH and chlorine concentration were not observed at potentials in the range -0.6 approximately 1.2 V vs. SCE. In a field experiment, accumulation of the bacterial cells and formation of biofilms on the electrode were prevented by application of an alternating potential, and 94% of attachment of the biofouling organisms was inhibited electrically on yarn used for fishing net coated with conductive paint. Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗

PubMed1998

Negative regulation by interleukin-3 (IL-3) of mouse early B-cell progenitors and stem cells in culture: transduction of the negative signals by betac and betaIL-3 proteins of IL-3 receptor and absence of negative regulation by granulocyte-macrophage colony-stimulating factor.

The receptors for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-5 share a common signaling subunit betac. However, in the mouse, there is an additional IL-3 signaling protein, betaIL-3, which is specific for IL-3. We have previously reported that IL-3 abrogates the lymphoid potentials of murine lymphohematopoietic progenitors and the reconstituting ability of hematopoietic stem cells. We used bone marrow cells from betac- and betaIL-3-knock-out mice to examine the relative contributions of the receptor proteins to the negative regulation by IL-3. First, we tested the effects of IL-3 on lymphohematopoietic progenitors by using lineage-negative (Lin-) marrow cells of 5-fluorouracil (5-FU)-treated mice in the two-step methylcellulose culture we reported previously. Addition of IL-3 to the combination of steel factor (SF, c-kit ligand) and IL-11 abrogated the B-lymphoid potential of the marrow cells of both types of knock-out mice as well as wild-type mice. Next, we investigated the effects of IL-3 on in vitro expansion of the hematopoietic stem cells. We cultured Lin-Sca-1-positive, c-kit-positive marrow cells from 5-FU-treated mice in suspension in the presence of SF and IL-11 with or without IL-3 for 7 days and tested the reconstituting ability of the cultured cells by transplanting the cells into lethally irradiated Ly-5 congenic mice together with "compromised" marrow cells. Presence of IL-3 in culture abrogated the reconstituting ability of the cells from both types of knock-out mice and the wild-type mice. In contrast, addition of GM-CSF to the suspension culture abrogated neither B-cell potential nor reconstituting abilities of the cultured cells of wild-type mice. These observations may have implications in the choice of cytokines for use in in vitro expansion of human hematopoietic stem cells and progenitors.

Animals↗

PubMed1998

Thrombopoietin promotes the survival of murine hematopoietic long-term reconstituting cells: comparison with the effects of FLT3/FLK-2 ligand and interleukin-6.

The effects of thrombopoietin (TPO; c-mpl ligand), FLT3/FLK-2 ligand (FL), and interleukin-6 (IL-6) on the survival of murine hematopoietic long-term reconstituting cells (LTRC) were studied by using lineage-negative, Sca-1-positive, c-kit-positive (Lin-Sca-1(+)c-kit+) marrow cells from 5-fluorouracil-treated mice. We tested the ability of these cytokines to maintain the viability of LTRC by transplanting the cultured cells to lethally irradiated Ly-5 congenic mice together with compromised marrow cells. As a single agent, only TPO could maintain the LTRC. Neither IL-6 nor FL was effective by itself, but they acted synergistically to maintain the LTRC. We examined whether the maintenance of LTRC by these cytokines was due to the survival of stem cells or was the result of active cell divisions and self-renewal. To monitor cell division, we used membrane dye PKH26. Enriched cells were stained with PKH26 on day 0 and incubated in suspension culture with TPO or with IL-6 and FL for 7 days. On day 7, PKH26(low) and PKH26(high) cells were prepared by sorting and their in vivo reconstituting abilities were tested by transplantation into lethally irradiated Ly-5 congenic mice together with compromised marrow cells. PKH26(high) populations cultured with both TPO alone and the combination of IL-6 and FL showed greater reconstitution activity than that of PKH26(low) populations. These data indicate that TPO alone and the combination of IL-6 and FL can support the survival of stem cells without stimulating their active cell proliferation.

Animals↗

PubMed1998

Concentrations of thrombopoietin in bone marrow in normal subjects and in patients with idiopathic thrombocytopenic purpura, aplastic anemia, and essential thrombocythemia correlate with its mRNA expression of bone marrow stromal cells.

The function of bone marrow (BM) stromal thrombopoietin (TPO) in megakaryopoiesis remains unknown. In the present study we attempted to clarify the pathophysiological implications of stromal TPO in normal subjects (NS) and in patients with idiopathic thrombocytopenic purpura (ITP), aplastic anemia (AA), and essential thrombocythemia (ET) by measuring TPO concentrations in BM and peripheral blood (PB) and by estimating the levels of stromal TPO mRNA with TaqMan fluorescence-based post-reverse transcription-polymerase chain reaction product detection system. The results showed that TPO concentrations in PB were significantly elevated in patients with ITP (34.9 +/- 11.7 pg/mL) and AA (364.1 +/- 153.5 pg/mL) but within normal range in patients with ET (each 20.0 and 22.1; NS, 22.1 +/- 8.2 pg/mL). In all subjects, the TPO concentrations in BM correlated well with the PB levels, and the former were consistently higher than the latter. The concentrations of TPO in BM also correlated with the levels of TPO mRNA in stromal cells. Furthermore, expression levels of TPO mRNA clearly correlated with megakaryocyte counts in NS and patients with ITP, indicating that stromal TPO actually enhances megakaryopoiesis. Thus, our results in the present study indicate that TPO from BM stromal cells is considered to play an essential role for megakaryopoiesis under various patho-physiological conditions.

Anemia, Aplastic↗

PubMed1998

Neuronal src and trk a protooncogene expression in neuroblastomas and patient prognosis.

Neuroblastomas present a wide variety of clinical and biological behaviors, which are reflected by the heterogeneous expressions of protooncogenes related to the neuronal differentiation and amplification of the N-myc gene. High expression of trk A and Ha-ras in neuroblastomas has been shown to be associated with an excellent patient outcome. We have previously reported that neuron-specific src mRNA was increased in chemically differentiated neuroblastoma cell lines and in clinically observed neuroblastomas without N-myc amplification. In the present study, to clarify both the value of neuronal c-srcN2 expression as a prognostic indicator and the significance of the coexpression of these protooncogenes, we examined the expression of 3 alternatively spliced src, trk A and Ha-ras in neuroblastoma tissues from 60 patients by competitive RNA-polymerase chain reaction (PCR). The results indicate that protooncogene expression in neuroblastomas correlated with a favorable outcome for c-srcN2 and trk A. N-myc gene was amplified exclusively in tumors with low levels of trk A. Low expression of c-srcN2 and trk A might thus characterize different aggressive phenotypes due to different signal transduction pathways of neural differentiation in neuroblastoma. The combined analyses for c-srcN2 and trk A expression by RNA-PCR should provide information about the biological phenotype of a neuroblastoma within a short period of time after obtaining tumor material.

Genes, myc↗