Biomedical subjects

H Matsuda

Publications and source records attributed to H Matsuda.

At least 415 records · Page 23Linked to original sources

PubMed1999

Chemical constituents from the leaves of Hydrangea macrophylla var. thunbergii (III): Absolute stereostructures of hydramacrosides A and B, secoiridoid glucoside complexes with inhibitory activity on histamine release.

Following the characterization of dihydroisocoumarin constituents, two secoiridoid glucoside complexes, called hydramacrosides A and B, were isolated from the leaves of Hydrangea macrophylla Seringe var. thunbergii Makino. The absolute stereostructures of hydramacrosides A and B were elucidated on the basis of chemical and physicochemical evidence, which included the application of the 13C-NMR glycosylation shift rule of 1,1'-disaccharides and the modified Mosher's method. Hydramacrosides A and B exhibited an inhibitory effect on histamine release from rat mast cells induced by an antigen-antibody reaction.

Acetylation↗

PubMed1999

Bioactive saponins and glycosides. XV. Saponin constituents with gastroprotective effect from the seeds of tea plant, Camellia sinensis L. var. assamica Pierre, cultivated in Sri Lanka: structures of assamsaponins A, B, C, D, and E.

The saponin fraction from the seeds of the tea plant, Camellia sinensis L. var. assamica Pierre cultivated in Sri Lanka, was found to show a potent protective effect on gastric mucosal lesions induced by ethanol in rats. Nine new acylated polyhydroxyoleanene-type triterpene oligoglycosides called assamsaponins A-I were isolated from the active saponin fraction together with three known saponins, theasaponin E1 and E2 and camelliasaponin B1. The structures of assamsaponins A-E were elucidated on the basis of chemical and physicochemical evidence. Theasaponin E1 exhibited potent gastroprotective activity.

Animals↗

PubMed1999

Medicinal flowers. I. Aldose reductase inhibitors and three new eudesmane-type sesquiterpenes, kikkanols A, B, and C, from the flowers of Chrysanthemum indicum L.

The methanolic extract from the flowers of Chrysanthemum indicum L., Chrysanthemi Indici Flos, was found to show inhibitory activity against rat lens aldose reductase. By bioassay-guided separation, the active components, such as flavone and flavone glycosides, were isolated from the extract together with three new eudesmane-type sesquiterpenes, kikkanols A, B, and C. The structures of kikkanols A, B, and C were elucidated on the basis of chemical and physicochemical evidence, which included application of the modified Mosher's method.

Aldehyde Reductase↗

PubMed1999

[Bioactive saponins and glycosides. XIII. Horse chestnut. (3): Quantitative analysis of escins Ia, Ib, IIa, and IIb by means of high performance liquid chromatography].

As a part of our studies on the characterization of bioactive saponin constituents of horse chestnut trees, a quantitative method using high performance liquid chromatography (HPLC) has been developed for four principle saponin constituents, such as escins Ia, Ib, IIa, and IIb, isolated from the seeds of European horse chestnut trees (Aesculus hippocastanum L., Hippocastanaceae). As an application of this HPLC method, we examined the contents and compositions of these escins in the seeds of Japanese horse chestnut trees (A. turbinata BLUME) and in several commercial materials named as "beta-escin". Additionally, the distribution of escins in the Japanese horse chestnut trees was examined, and escins were found to be contained only in the seeds.

Chromatography, High Pressure Liquid↗

PubMed1999

Purification, characterization and gene analysis of N-acetylglucosaminidase from Enterobacter sp. G-1.

Enterobacter sp. G-1 is a bacterium isolated previously as a chitinase-producing bacterium. We found this bacterium also produced N-acetylglucosaminidase and characterized that in this study. Extracellular N-acetylglucosaminidase of 92.0 kDa was purified near homogeneity by 8.57-fold from Enterobacter sp. G-1. The optimum temperature and the optimum pH of the purified N-acetylglucosaminidase was 45 degrees C and 6.0, respectively. The N-terminal amino acid sequence of 23 residues of N-acetylglucosaminidase was identified. Based on the N-terminal sequence, we amplified pieces of the DNA fragments by PCR. Using these PCR products as probes, we screened the genomic library and successfully isolated the entire N-acetylglucosaminidase gene (designated nag1) from Enterobacter sp. G-1. The nucleotide sequence of the nag1 gene was found to consist of 2,655 bp encoding a protein of 885 amino acid residues. Comparison of the deduced amino acid sequence from the nag1 gene found 97.3% identity with chitobiase from Serratia marcescens, 54.4% identity with N,N'-diacetylchitobiase from Vibrio harveyi, and 42.7% identity with N-acetylglucosaminidase (ExoI) from Vibrio furnissii. Enzymatic activity assay of N-acetylglucosaminidase indicated stronger activity toward PNP-GlcNAc than PNP-(GlcNAc)2 or PNP-(GlcNAc)3.

Acetylglucosaminidase↗

PubMed1999

Two cytosolic cyclophilin genes of Arabidopsis thaliana differently regulated in temporal- and organ-specific expression.

We have previously isolated two closely related genes (ATCYP1 and ATCYP2) each encoding a cytosolic cyclophilin of Arabidopsis thaliana. Here we tested expression patterns of these two genes by Northern analysis and by histochemical analysis with transgenic plants carrying the promoter: beta-glucuronidase (GUS) fusion. The results showed that ATCYP1 is predominantly transcribed in vascular tissue and flowers, but ATCYP2 is at higher levels in younger leaves. The different expression patterns seemed to be conferred by the quite different promoter structures carrying various cis elements. Our finding suggests that the two cyclophilins have different roles in Arabidopsis thaliana cells.

Arabidopsis↗

PubMed1999

Evidence for norepinephrine-activated Ca2+ permeable channels in guinea-pig hepatocytes using a patch clamp technique.

To determine whether the hepatocyte plasma membrane possesses a Ca2+ channel. we applied a patch clamp technique to isolated guinea-pig hepatocytes. In a cell-attached configuration, using an internal pipette solution of 110 mM BaCl2 or CaCl2, we observed sporadic inward single channel currents (Po = 0.004 +/- 0.002, n = 6) at various membrane potentials. The unit amplitude was 0.60 +/- 0.15 pA (n = 6) at resting membrane potential. The single channel conductance was 20.4 +/- 4.6 pS (n = 6) and this channel showed no rectification and no voltage dependence. Bay K 8644, a dihydropyridine Ca2+ channel activator, did not affect this channel activity. Although norepinephrine in the pipette solution did not activate this channel, its external application increased channel activity. These observations suggest that guinea-pig hepatocytes possess Ca2+ permeable channels that differ from the voltage-operated Ca2+ channels found in excitable cells and that such channels are responsible for the agonist-stimulated Ca2+ entry in hepatocytes.

Animals↗

PubMed1999

Impaired nitric oxide-independent dilation of renal afferent arterioles in spontaneously hypertensive rats.

Sustained hypertension alters vasomotor regulation in various vascular beds. We studied whether nitric oxide (NO)-dependent and NO-independent vasodilator mechanisms are altered in renal microvessels in hypertension. To directly visualize the renal microcirculation, the isolated perfused hydronephrotic rat kidney model was used. After pretreatment with indomethacin (100 micromol/l), afferent arterioles were constricted by norepinephrine (NE) or by increasing renal arterial pressure (i.e., myogenic constriction; from 80 to 180 mmHg). Acetylcholine (ACH) was then added, and the renal microvascular response was assessed by computer-assisted video image analysis. A similar protocol was conducted in the presence of nitro-L-arginine methylester (L-NAME; 100 micromol/l). During NE constriction, ACH caused dose-dependent and sustained vasodilation of the afferent arteriole, similar in magnitude in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). In the presence of L-NAME, ACH (0.01-1 micromol/l) elicited only transient dilation, and the degree of vasodilation was very low in SHR. During myogenic constriction, afferent arterioles from WKY and SHR kidneys responded to ACH with only transient vasodilation, which was unaffected by NO inhibition; the transient vasodilative responses elicited by ACH (0.1-1 micromol/l) were smaller in SHR than in WKY. In conclusion, ACH has both sustained and transient vasodilative effects on the afferent arteriole. Sustained vasodilation is attributed to NO generation, which is similar in WKY and SHR. In contrast, transient vasodilation, mediated by NO-independent vasodilator factors, is impaired in SHR. Deranged vasodilatory mechanisms in hypertension may disturb the renal microcirculation, which may result in renal injury.

Acetylcholine↗

PubMed1999

In vitro system for immunoglobulin class switching using BHK cells transfected with murine recombinant CD40 ligand.

To develop an in vitro system for mouse immunoglobulin (Ig) class switching, the expression vector of murine CD40 ligand (CD40L) which is expressed on T cells was transfected to BHK cells. By using culture plates coated with the BHK cells expressing the recombinant CD40L, Ig class switching of splenic B cells was examined. The CD40L mRNA was cloned from splenic T cells of BALB/mice activated with anti-CD3 antibody in vitro. As the No.593 base in the open reading frame sequence of the CD40L from BALB/c spleen differed from T to G, when compared with the known sequence from C57BL/6, one of the BALB/c-derived clones was reconstructed to the known CD40L by site-directed mutagenesis. Splenic B cells from BALB/c were induced secretion of Ig isotypes, IgM, IgG1 and IgE when cultured on two types of BHK cells, the transfected BHK cells with a CD40L clone from BALB/c and the transfected BHK cells with the reconstructed CD40L clone, in the presence of IL-4. However, when splenic B cells from C57BL/6 were cultured on the same systems, the B cells produced Ig isotypes, IgM, IgG1, IgG2a, IgG2b, IgG3 and IgE. In the similar experiments using the transfected BHK cells with a empty vector and the normal BHK cells, none of B cells produced any Ig isotypes other than IgM. These results indicate that Ig class switching of murine B cells can be induced by using these two types of CD40L-expressing BHK cells in vitro.

Animals↗

PubMed1999

Changes in the distribution of the substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the laryngeal mucosa of chronically hypoxic rats.

The distribution and abundance of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive nerve fibers in four different regions of the laryngeal mucosa were compared between normoxic and chronically hypoxic rats (10% O2 and 3.0-4.0% CO2 for 3 months). In the chronically hypoxic laryngeal mucosa, the number of SP and CGRP fibers within and just beneath the epithelium, and around the laryngeal gland was increased in comparison with those in the normoxic controls. Especially in the epiglottic and arytenoid regions, the number of intraepithelial SP fibers was increased remarkably. Most intraepithelial SP and CGRP fibers penetrated into the epithelium to extend to the luminal surface. There was no distinct difference in the distribution and abundance of these peptidergic fibers in the mucosa of the normoxic and chronically hypoxic vocal cord regions. These results suggest that the increased density of SP and CGRP fibers within the epithelium of the upper laryngeal mucosa is a predominant feature of hypoxic adaptation, and this may be involved in airway protection, swallowing, and other functions in the chronically hypoxic environment. In addition, the increased SP and CGRP fibers around the laryngeal gland suggest an enhanced mucous secretion, and this may participate in the airway defense mechanism in low O2 conditions.

Animals↗

PubMed1999

Zonal heterogeneity in action of angiotensin-converting enzyme inhibitor on renal microcirculation: role of intrarenal bradykinin.

The present study examined the role of intrarenal bradykinin in angiotensin-converting enzyme inhibitor (ACEI)-induced dilation of renal afferent (AFF) and efferent arterioles (EFF) in vivo, and further evaluated whether ACEI-stimulated bradykinin activity differed in superficial (SP) and juxtamedullary nephrons (JM). Arterioles of canine kidneys were visualized with an intravital charge-coupled device camera microscope. E4177 (an angiotensin receptor antagonist, 30 microg/kg) dilated AFF and EFF in SP (15 +/- 3% and 19 +/- 5%) and JM (15 +/- 3% and 18 +/- 4%). Subsequently, cilazaprilat (30 microg/kg) caused further dilation of both AFF (29 +/- 4%) and EFF (36 +/- 4%) in JM, whereas in SP it dilated only EFF (29 +/-3%). Similarly, in the presence of E4177, cilazaprilat caused further increases in sodium excretion. This cilazaprilat-induced vasodilation and natriuresis was abolished by a bradykinin antagonist (N(alpha)-adamantaneacetyl-D-Arg-[Hyp3,Thi5,8,D-Phe7]b radykinin). In parallel with these results, cilazaprilat increased renal bradykinin content, more greatly in the medulla than in the cortex (5.7 +/- 0.4 versus 4.6 +/- 0.1 ng/g). Similarly, cilazaprilat elicited greater bradykinin-dependent increases of nitrite/nitrate in the medulla. In conclusion, zonal heterogeneity in renal bradykinin/nitric oxide levels and segmental differences in reactivity to bradykinin contribute to the diverse responsiveness of renal AFF and EFF to ACEI. ACEI-enhanced kinin action would participate in the amelioration of glomerular hemodynamics and renal sodium excretion by ACEI.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1999

[Reconstruction of great vessel for patients with advanced lung cancer or malignant mediastinal tumor].

Fifteen lung cancer (LC) and 11 malignant mediastinal tumor (MMT) patients who received surgical treatment in association with a reconstruction of great vessel from 1981 to 1997 were retrospectively reviewed. The aorta was resected in 7 (AO group) of 15 LC patients and the superior vena cava in the remaining 8 patients (SVC group). Pathological examination revealed actual tumor invasion in one (14%) of AO group and 6 (75%) of SVC group. In 7 p-T4 patients, 6 (85.7%) were p-N2 or N3 diseases. Five of the 6 patients belonged to SVC group and one to AO group. Five-year survival rate was 10% in all LC patients, 20% in p-T3 patients, 0% in p-T4 cancers, 50% in p-N0 patients and 0% in p-N2 or N3 patients. Eleven MMT patients included 5 thymomas, 2 thymic cancers and 4 germ cell tumors. SVC was resected and replaced with ringed PTFE graft in all patients. Invasion of vessel wall was diagnosed pathologically in 10 of 11 patients. Fifteen-year survival rate was 60% in 5 thymoma patients but 4 of whom had distant metastasis. Five-year survival rate was 50% in thymic cancers and 0% in germ cell tumors. Since the prognosis of LC and MMT patients who have tumor invasion of the great vessel is very poor, induction therapy based on preoperatively pathological diagnosis is recommended.

Adult↗

PubMed1999

[Longitudinal evaluation of early dementia of Alzheimer type using brain perfusion SPECT].

Regional cerebral blood flow (rCBF) measurements using a Patlak plot method of 99mTc-ECD were performed in early dementia of Alzheimer type (DAT) with both HDS-R and MMSE of over 20 to investigate initial abnormality and longitudinal changes of rCBF. A fusion technique of MRI and SPECT images was developed for MRI-guided analysis of regions of interest in hippocampal areas and statistical parametric mapping (SPM) was used for automated and objective approach to analysis of SPECT image data. Seventeen patients with clinically diagnosed early DAT and age-matched 32 normal control subjects were studied. At the first SPECT studies, the mean cerebral blood flow (mCBF) of 38.6 +/- 4.7 ml/100 g/min (mean +/- SD) for early DAT did not show significant reduction as compared with the normal control value of 42.0 +/- 3.8, whereas the rCBF values in the bilateral hippocampi (right; 26.8 +/- 4.7, left; 26.7 +/- 5.2) showed significant reduction (p < 0.05) as compared with the normal control values (right; 38.3 +/- 4.2, left; 38.4 +/- 3.8). The SPM analysis (voxel height; p < 0.001, Bonferroni correction; p < 0.05) of the first SPECT images revealed significant selective decrease of relative rCBF in the bilateral posterior cingulate gyri. At the second SPECT studies after 1.4 year on the average from the first studies, mCBF for early DAT showed a slight decrease by 1.7 +/- 3.8 ml/100 g/min/year. Bilateral hippocampi showed a greater decrease with slight left-side dominance by 3.8 +/- 3.3 on the right and 4.4 +/- 3.2 on the left side. The SPM analysis demonstrated significant decrease of relative rCBF in the basal fore-brain area, the left hippocampus, the left amygdala, and the left parahippocampal area. These results suggest that the MRI-guided ROI analysis of rCBF values in the hippocampus and the SPM analysis of SPECT images are quite useful for early diagnosis and follow-up of DAT.

Aged↗

PubMed1999

[Assessment of a new non-invasive cerebral blood flow determination method using the brain uptake ratio of 99mTc-ECD].

We modified the method of calculating brain uptake ratio (BUR) reported previously, and devised a new non-invasive cerebral blood flow measurements for 99mTc-ECD that does not require blood sampling. This method yields BUR that is not influenced by the gamma camera type and the choice of acquisition-reconstruction conditions, when corrected by the SPECT/Planar cross calibration coefficient. A good correlation was observed between the BUR obtained by this method and the cerebral blood flow (CBF) obtained by the 123I-IMP continuous arterial blood sampling method. And based on these results, it is now possible to convert BUR to CBF. This method is applicable to small field type of gamma cameras, and it is expected to be useful as a routine test.

Brain↗

PubMed1999

Inhibition of gastric emptying by triterpene saponin, momordin Ic, in mice: roles of blood glucose, capsaicin-sensitive sensory nerves, and central nervous system.

The roles of capsaicin-sensitive sensory nerves and the central nervous system in the inhibitory effect of momordin Ic, a principal saponin constituent in various Chinese and Japanese herbal medicines, such as the fruit of Kochia scoparia (L.) SCHRAD., on gastric emptying were investigated in nonnutrient meal- or nutrient meal-loaded mice. Momordin Ic (12.5-50 mg/kg) significantly inhibited gastric emptying in 1.5% carboxymethyl cellulose sodium salt test meal-loaded mice by 8.4%-60.6%, 40% glucose test meal-loaded mice by 42.8% (50 mg/kg), milk test meal-loaded mice by 36.4% (50 mg/kg), and 60% ethanol test meal-loaded mice by 37.2% (50 mg/kg). The inhibitory effect on the gastric emptying in 1.5% carboxymethyl cellulose sodium salt test meal-loaded mice was potentiated by glucose (2 g/kg, i.v. or 5 g/kg, i.p.), but markedly attenuated by pretreatment with alloxan (50 mg/kg, i.v.) and streptozotocin (100 mg/kg, i.v.), in which the activity of sympathetic nervous system was decreased, or by insulin (1 or 3 U/kg, s.c.). The effect of insulin (1 U/kg) was markedly reduced by glucose (2 g/kg, i.v.), which can directly nourish the brain, but not by fructose (2 g/kg, i.v.), which cannot be used by the brain. The effect of momordin Ic was also attenuated by pretreatment with capsaicin (75 mg/kg in total, s.c.). These results suggest that the inhibition of gastric emptying by momordin Ic is relative to serum glucose and, at least in part, mediated by capsaicin-sensitive sensory nerves and the central nervous system.

Animals↗

PubMed1999

[Surgery for mitral regurgitation in children].

In pediatric patients, mitral valve (MV) repair is preferable than MV replacement because of no need for anticoagulation and its feasibility in small children. However, long-term outcome of MV repair is still unclear. In the present study, fifty-two pediatric patients who underwent MV repair (n = 46) and MV replacement (n = 6) against mitral regurgitation (MR) between January 1970 and December 1996 were evaluated. 46 patients had associated diseases. Mitral annuloplasty was applied in 20 patients (by Kay method (n = 14) and Paneth-Burr method (n = 6) before and after 1991, respectively). Freedom from reoperation rate in patients with partial endocardial cushion defect (ECD) was significantly lower than that in other patients after MV repair, which was significantly higher than that in patients with MV replacement. Diameter of mitral annulus grew within normal range after MV repair. In conclusion, MV repair may provide better outcomes with respect to reoperation and growth of MV in pediatric patients except with partial ECD.

Cardiac Surgical Procedures↗

PubMed1999

Corneal wound healing in tenascin knockout mouse.

PURPOSE: Tenascin (TN) is a large hexameric extracellular matrix glycoprotein that is expressed in developing organs and tumors. It has also been reported that TN is expressed in the embryonic cornea and during corneal wound healing. However, the role of TN in the cornea is not fully known. In this study, the role of TN in corneal wound healing was examined using the TN knockout (KO) mouse. METHODS: Two different injuries (a linear perforation wound and two 10-0 nylon suture wounds) were made separately on the corneas of both TNKO and congenic wild-type mice. The corneal wound healing was compared histologically, and the expression of TN and fibronectin (FN) on the injured cornea was examined immunohistochemically and by immunoblot analysis. RESULTS: Based on histologic analysis, there was no significant difference in the wound healing process between wild-type and TNKO mice in the linear incision experiment. However, the corneal stromata of TNKO mice were compressed prominently and devoid of migrating keratocytes in suture injury, which induced a more significant amount of TN than perforation wounds. Although FN expression on the sutured corneas of TNKO mice was upregulated during suture injury, the amount of FN protein was smaller than that of wild-type mice at the same time points after injury. CONCLUSIONS: In suture wounds, TN appears to enhance the amount of FN expression, and a lack of TN may impair stromal cell migration. TN plays a significant role in corneal wound healing, especially for wounds with mechanical stress.

Animals↗

PubMed1999

Simultaneous surgery for infective endocarditis and endophthalmitis.

A 54-year-old woman was diagnosed as having septicemia secondary to infective endocarditis with aortic regurgitation which was complicated by endophthalmitis. Her septicemia was controlled by intravenous antibiotic therapy. Then the localized eye infection and the aortic regurgitation with a massive vegetation were surgically treated simultaneously. She had no relapse of infection after intensive postoperative antibiotic therapy.

Endocarditis, Bacterial↗