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Biomedical subjects

N Matsuda

Publications and source records attributed to N Matsuda.

At least 73 records · Page 4Linked to original sources
PubMed1998

Perioperative changes in plasma brain natriuretic peptide concentrations in patients undergoing cardiac surgery.

The plasma concentrations of brain natriuretic peptide (BNP), a cardiac hormone, were measured in 30 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) during the perioperative period. BNP concentrations remained unchanged until 6 h after the cessation of bypass, and were elevated 12, 24, and 48 h post-bypass (P < 0.0001 versus baseline). They had returned to the baseline values when measured 3 weeks postoperatively. The preoperative plasma BNP concentration correlated significantly with the left ventricular ejection fraction (r = -0.895). The peak plasma BNP concentration 24 h after bypass correlated with the cardiac index (r = -0.64), stroke volume index (r = -0.62), injection rate of dopamine hydrochloride (r = 0.65), and aortic crossclamp time (r = 0.57). There was also a significant correlation between the preoperative BNP concentration and the plasma BNP concentration 24 h post-CPB. These findings led us to conclude that the plasma concentrations of BNP become markedly and acutely elevated after cardiac surgery with CPB, and reflect the state of left ventricular function. Moreover, the severity of acute heart failure after cardiac surgery can be predicted by the preoperative plasma BNP concentration.

Cardiac Surgical Procedures↗
PubMed1998

[Postoperative therapy using human atrial natriuretic peptide in cases of valve replacement].

The effect of hANP (atrial natriuretic peptide) was investigated clinically in 40 patients who underwent isolated valve replacement. Patients were divided into four groups: aortic regurgitation (AR), aortic stenosis (AS), mitral regurgitation (MR) and mitral stenosis (MS). Each group was divided into two subgroups: one was administered hANP after the operation until leaving ICU, and the other was not administered hANP. We measured the levels of hANP and c-GMP and blood pressure, pulmonary artery pressure, central venous pressure and levels of Na, K of urine and blood prcoperatively, immediately postoperatively and 1, 2, 4, 6 hours after operation. First, to examine the relationship between preoperative level of hANP and cardiac function, the relationship between preoperative level of hANP and history of cardiac failure and pulmonary artery wedge pressure (PAWP) were evaluated. Also, we evaluated the relationship between preoperative level of hANP and each dimension on echocardiography. There was a weak statistical relationship between hANP and PAWP (row = 0.39 (p = 0.04) Pearson correlation method) and there was no statistical relationship between hANP and duration of cardiac failure (row = 0.00445 (p = 0.98) Pearson correlation method). Preoperatively Left atrial diameter (LAD) showed a statistical relationship with level of hANP in every group using Spearman correlation method. Other dimensions such as left ventricular diastolic diameter (LVDd) and left ventricular systolic diameter (LVDs) and also fractional shortening (FS) did not show a strong correlation with preoperative level of hANP. Especially, in AS group there was a strong relationship between every dimension and preoperative level of hANP. Only in MS group LAD and the level of hANP were negatively related. This finding suggests that atrial dilatation results in reduction of secretion of hANP in cases of MS on long term follow up. Finally, hNAP therapy was shown to have a continuous diuretic effect, with stable hemodynamics.

Adult↗
PubMed1998

Role of epidermal growth factor and its receptor in mechanical stress-induced differentiation of human periodontal ligament cells in vitro.

The periodontal ligament (PDL) contains precursor cells for osteoblasts and cementoblasts. It has been shown that epidermal growth factor (EGF) inhibits dexamethasone-induced differentiation and up-regulates EGF-receptor (EGF-R) expression, whereas EGF-R is down-regulated in the course of differentiation. Thus it was suggested that EGF and its receptors act as a negative regulator of osteoblastic differentiation in PDL cells. In order to investigate further this hypothesis, human PDL cells were now used to elucidate the role of EGF and EGF-R in their proliferation and differentiation under mechanical stress-loaded conditions in vitro, as the PDL regularly receives mechanical stress from occlusal forces. As a model of mechanical stress, a cyclic stretch of 9 or 18% elongation was applied to the cells with a Flexercell cell-strain unit system. Alkaline phosphatase activity and osteocalcin mRNA expression were significantly induced by loading cyclic stretch for more than 4 days, whereas stretch slightly inhibited cell proliferation. Visualization of the actin stress fibres of the cells by rhodamine phalloidin revealed that approx. 10% of the total number of cells had become aligned perpendicularly to the direction of the stretch. The effects of stretch on alkaline phosphatase activity and cell proliferation were totally abolished by the presence of 10 ng/ml EGF. Western blotting of EGF-R protein demonstrated that stretch-induced differentiation accompanied the decreased expression of EGF-R protein in the cells. However, the amount of tyrosine-phosphorylated EGF-R upon EGF stimulation was restored to the control level in stretched cells. These results suggest that the EGF/EGF-R system acts as a negative regulator of differentiation of PDL cells regardless of the type of differentiation stimuli. Also, interaction between mechanical stress and the EGF/EGF-R system may participate in the osteoblastic differentiation of PDL cells and thereby regulate the source of cementoblasts and osteoblasts.

Actins↗
PubMed1998

RMA1, an Arabidopsis thaliana gene whose cDNA suppresses the yeast sec15 mutation, encodes a novel protein with a RING finger motif and a membrane anchor.

To identify molecules that function in the plant secretory pathway, we screened for Arabidopsis thaliana cDNA clones that complement the temperature-sensitive (ts), secretion-deficient sec15 mutation of yeast Saccharomyces cerevisiae. RMA1, one of the genes obtained in this screening, suppressed not only the ts growth of sec15 but also its secretory defect. RMA1 is not a structural homologue of SEC15 but encodes a novel 28 kDa protein with a RING finger motif and a C-terminal membrane-anchoring domain. Mutational analysis indicates that the RING finger motif of RMA1 is important for its suppression activity. In Arabidopsis plant, RMA1 is ubiquitously expressed. A search for homologous proteins in the database revealed that Arabidopsis, nematode, mouse and human possess close homologues of RMA1.

Amino Acid Sequence↗
PubMed1998

Porphyromonas gingivalis lipopolysaccharide modulates the responsiveness of human periodontal ligament fibroblasts to platelet-derived growth factor.

Lipopolysaccharides (LPS) prepared from periodontopathic bacteria have been known to induce various biological responses which may lead to periodontal tissue breakdown. The purpose of this study was to determine if Porphyromonas gingivalis LPS could affect cellular functions of human periodontal ligament fibroblasts (HPLF). We showed here the responsiveness of cultured HPLF to platelet-derived growth factor (PDGF)-BB, a growth factor for mesenchymal cells, in the presence of P. gingivalis LPS. DNA synthesis of HPLF was enhanced in a dose-dependent manner when LPS were co-incubated for 48 h; thereafter, it decreased to the baseline level within 24 h incubation. The stimulating effect of PDGF-BB was further enhanced by the pretreatment of HPLF with LPS (10 micrograms/ml) for 48 h. The binding assay of [125I]PDGF-BB and the flow cytometric assay using rabbit antiserum to human PDGF receptor (PDGF-R) beta-type indicated that this enhancement was due to the increase of the number of PDGF-R beta-type on HPLF. Immunoprecipitation using antiserum to human PDGF-R beta-type also showed that the synthesis of PDGF-R beta-type was augmented in the LPS-treated HPLF. These results indicate that P. gingivalis LPS stimulate cellular proliferation and responsiveness to PDGF-BB of cultured HPLF. These cellular reactions may be mediated by PDGF-BB binding, followed by increased synthesis of the receptor protein.

Becaplermin↗
PubMed1998

Effects of tea infusions of various varieties or different manufacturing types on inhibition of mouse mast cell activation.

We investigated effects of various tea infusions on mast cell activation using mouse mast cells. Among various tea extracts, infusions from cultivar 'Benihomare' and Taiwan lineage strongly inhibited histamine release after Fc epsilon RI cross-linking. Among three types of tea (from cultivar 'Benihomare'), extract from oolong tea or black tea inhibited histamine release more strongly than green tea extract. Furthermore, 'Benihomare' oolong tea extract suppressed tyrosine phosphorylation of cellular proteins after Fc epsilon RI cross-linking, but polyvinyl polypyrrolidone treatment of the extract to remove phenolic compounds, weakened the suppressive effect.

Animals↗
PubMed1998

Inter-laboratory difference among eleven clinical laboratories in the Okayama City area.

The aim of the present study was to find the cause of inter-laboratory differences in laboratory test data and to examine whether control assessment helps to reduce inter-laboratory differences. Blood and serum samples of one healthy subject and one subject with liver cirrhosis were analyzed by 11 laboratories in the Okayama City area. No differences were found in the assay units of 26 tests surveyed. However, considerable differences were observed in test data, reference interval, and clinical level (CL), though most laboratories pointed out that the test data for the normal subject was within the reference intervals and those for the patient with liver cirrhosis showed abnormalities in tests for liver function. The difference in reference intervals was serious in the tests of direct bilirubin (D-Bil), thymol turbidity test (TTT), alkaline phosphatase (ALP), gamma-glutamyltranspeptidase (GGTP) and choline sterase. Marked differences in CLs were found in the tests of D-Bil, TTT, ALP, GGTP, creatine phosphokinase, amylase, heavy density lipoprotein cholesterol and white blood cell count. However, three hepatologists independently suggested that such inter-laboratory differences would not seriously affect a clinical decision on the disease status of the cirrhotic patient. Most tests that showed a trend error in a recent quality control survey appeared to have the same trend in the present study. These results indicate that inter-laboratory differences occur at various levels and control assessment are helpful in establishing, and therefore reducing, the level of inter-laboratory differences.

Aged↗
PubMed1998

[Clinical study on chlormadinone acetate alone followed by combination with LH-RH analogue for prostatic cancer: effects on lipid metabolism].

Twenty-four previously untreated patients with a diagnosis of prostatic cancer were treated with chlormadinone acetate (CMA) alone (100 mg/day) for 4 weeks, and luteinizing hormone-releasing hormone analogue (LH-RHa) was added for the next 24 weeks. Marked decreases in blood LH, testosterone (T), prostate specific antigen (PSA), gamma-seminoprotein (gamma-Sm), and prostatic acid phosphatase (PAP) were observed after a single dose of CMA. T levels were significantly increased 3 days after the initial dose of LH-RHa, and did not return to the pretreatment level. There were no significant increases in any of the markers, nor were there any flare-up cases. Triglyceride levels, which were slightly elevated before the start of treatment, were significantly decreased 24 weeks after the completion of combined therapy. PSA was evaluated as partial response (PR) or better in 86.7% of the patients. Overall evaluation showed PR or better in 75.0% of the patients. These findings suggest that prior administration of CMA followed by combined administration with LH-RHa is useful in the treatment of prostatic cancer. No negative effects on lipid metabolism were observed at any time during the treatment period.

Aged↗
PubMed1998

[Consultation service for efficacious usage of laboratory tests based on logical reasoning and evidence].

To effectively respond to the desire for consultation in clinical practice, we must prepare logical reasoning and evidence which rationally supports laboratory test selection, the interpretation of test results and recommendation of certain tests to physicians. Standard of medical decision making can be used for logic issues such as posttest probability, test characteristics and receiver operating characteristics (ROC) curves and establishing appropriate cut-off points. Although we usually obtain evidence by consulting authorities or the literature, good evidence can also be obtained from meta-analysis. In addition, we can demonstrate the relationship of laboratory tests among several frequently occurring diseases and epidemiological tendencies such as frequency of causative organisms at several infection sites and bacterial sensitivities to antimicrobial agents, because we have access to a large-scale laboratory database. To construct a well-organized knowledge base with explicit evidence, cooperation among many facilities is necessary to develop system, which allows the free exchange of data.

Artificial Intelligence↗
PubMed1998

[Multivariate analysis of the associations between laboratory data and clinical features among patients with infectious mononucleosis syndrome].

Infectious mononucleosis (IM) syndrome is typically caused by EBV, but also by drugs and other organisms such as CMV and HBV. It demonstrates a wide range of clinical and laboratory characteristics, presumably depending on the age of onset. However, associations of laboratory abnormalities with the clinical features have not been well documented. We evaluated here, the associations among patients with IM syndrome using of multiple regression (MR) and multiple logistic regression (MLR) analyses. We examined 90 (40 males, 50 females) patients, who were admitted to our hospital with IM syndrome. The diagnostic criteria were fever and presence of atypical lymphocytes (> 5% of the WBC or the count including monocytes > 5000/microliter), and at least 3 of 7 clinical features: tonsillitis, lymphadenopathy, skin rash, hepato-, spleno-megaly, hepatic dysfunction. The diagnosis of EBV was serologically confirmed in 41 cases. MR revealed that the higher age group tended to have lower platelet counts, and that lower platelet counts were associated with higher ALT levels. In addition, MLR revealed that patients with skin rash tended not to have splenomegaly. The frequency of splenomegaly was not related to age, contrary to the findings of previous reports. These findings are useful to differentiate IM syndrome based on laboratory data.

Adolescent↗
PubMed1998

[Computer-assisted education of laboratory medicine based on common disease database and electric RCPC system using Internet technology].

We are developing computer-assisted instruction systems (CAI) for efficient education of laboratory medicine. To practice evidence-based laboratory medicine and put the education along the way, we gathered a large number of clinical records and constructed a database of clinical symptoms and signs of major diseases. We also constructed a web-based RCPC system featuring interactive multimedia materials and Q/A sessions to guide the students along important points in laboratory interpretations. We have been using these systems for 5th grade medical students and evaluated the effectiveness of them for the students to obtain knowledge regarding laboratory diagnosis. Although we still have a lot of aspects to improve, students showed interests in them and used them willingly. We believe that these CAI systems contribute to raise students' ability of problem solving in laboratory medicine.

Computer-Assisted Instruction↗
PubMed1997

Idiopathic ventricular fibrillation induced with vagal activity in patients without obvious heart disease.

BACKGROUND: Recently, idiopathic ventricular fibrillation (VF) has gained much attention. Although several subgroups have been described, its pathogenesis, mechanism, treatment, and prognosis remain unknown. METHODS AND RESULTS: We studied six cases of idiopathic VF with transient late r' waves and ST elevation (late r'/ST elevation) in leads V1 through V3. Late r'/ST elevation was augmented before and after VF episodes. Signal-averaged ECGs showed late potentials even when no late r'/ST elevation occurred. During late r', a conduction delay was observed by use of body-surface maps at the anterior wall and outflow tract of the right ventricle without inhomogeneity of the repolarization phase. There was a decrease or total disappearance of late r'/ST elevation with isoproterenol, atropine, and exercise stress testing and induction or exacerbation with propranolol, edrophonium, and hyperventilation. VF was induced by programmed electrical stimulation in all cases but two, in which it was induced only after edrophonium injection. In two cases, VF was exacerbated by propranolol, and in all cases, it was uninducible with isoproterenol. Heart rate spectral analysis just before VF episodes showed a sudden rise in vagal activity in two cases. As the VF mechanism, a conduction delay exists at the anterior wall and outflow tract of the right ventricle that is possibly exacerbated by an abrupt rise in vagal activity, inducing random reentry that results in VF. Class I antiarrhythmic agents and beta-blockers were ineffective for this VF. All subjects required implantable cardioverter-defibrillators. CONCLUSIONS: We propose this VF associated with late r'/ST elevation in the precordial leads and influenced by vagal activity as a new possible mechanism of idiopathic VF.

Adult↗
PubMed1997

Three members of the S multigene family are linked to the S locus of Brassica.

Two self-incompatibility genes in Brassica, SLG and SRK (SLG encodes a glycoprotein; SRK encodes a receptor-like kinase), are included in the S multigene family. Products of members of the S multigene family have an SLG-like domain (S domain) in common, which may function as a receptor. In this study, three clustered members of the S multigene family, BcRK1, BcRL1 and BcSL1, were characterized. BcRK1 is a putative functional receptor kinase gene expressed in leaves, flower buds and stigmas, while BcRL1 and BcSL1 are considered to be pseudogenes because deletions causing frameshifts were identified in these sequences. Sequence and expression pattern of BcRK1 were most similar to those of the Arabidopsis receptor-like kinase gene ARK1, indicating that BcRK1 might have a function similar to that of ARK1, in processes such as cell expansion or plant growth. Interestingly, the region containing BcRK1, BcRL1 and BcSL1 is genetically linked to the S locus and the physical distance between SLG, SRK and the three S-related genes was estimated to be less than 610 kb. Thus the genes associated with self-incompatibility exist within a cluster of S-like genes in the genome of Brassica.

Amino Acid Sequence↗
PubMed1997

Helicobacter pylori infection and genetic polymorphisms for cancer-related genes in gastric carcinogenesis.

The development of gastric cancer is a multistep process that is multi-factorial. An association with the Helicobacter pylori infections, gastric atrophy and gastric cancer has received recent attention. The objective of this study was to elucidate the risk factors for gastric cancer by using molecular epidemiological techniques for genetic susceptibility, gastric atrophy and serum markers including H pylori infection. We used an age- and gender-matched case-control study, where patients with benign gastric lesions were the controls. Low serum pepsinogen I levels (cut-off < 50 ng/mL) and low pepsinogen I/pepsinogen II ratios (cut-off < 3.0) were significantly associated with the risk of gastric cancer (odds ratio [OR] = 3.53: 95% confidence interval [CI] = 2.46-5.09 and OR = 4.73: 3.26-6.88, respectively). However, seropositivity of serum immunoglobulin G (IgG) antibody against H pylori (OR = 1.09: 0.74-1.61) was not associated with gastric cancer, even when analyzed by age greater than or less then 50 years. Specific genotypes of the cytochrome p450 2E1 (CYP2E1) RsaI polymorphism and glutathione-S-transferase (GST) M1 gene deletion were determined but were not associated with gastric cancer; however, a Lmyc genetic polymorphism was associated with gastric cancer (OR = 1.55: 1.03-2.34). Therefore, in this Japanese study, atrophic mucosal change, indicated by serum pepsinogen levels, is a possible risk factor for gastric cancer.

Helicobacter Infections↗
PubMed1997

Experience of patients with end-stage heart failure who underwent heart transplant at UCLA.

From 1993 to 1997, nine Japanese heart transplant candidates were accepted by the University of California at Los Angeles (UCLA) Medical Center, because no donor heart was available in Japan from a brain-dead patient. In all nine heart transplant patients described in this investigation, the preoperative diagnosis was dilated cardiomyopathy. One patient underwent implantation with a Novacor left ventricular assist device (Baxter Japan, Tokyo, Japan) as a bridge to heart transplant. All patients survived surgery and for a long-term period. The actuarial 1-year and 3-year survival curves of these patients were both 100%. The postoperative functional status was New York Heart Association Class 1 in all patients (100%). Immunosuppressive triple drug therapy (azathioprine, steroids, and cyclosporine) was given in seven patients; in two patients, cyclosporine was withdrawn and replaced by FK506 due to refractory rejection. The incidence of acute rejection per patient of more than grade 3 according to the International Society for Heart and Lung Transplantation was 6% within 3 months and 4.5% in 3-6 months; there was no rejection episode more than 6 months after transplantation. Post-transplant coronary artery disease was seen in two patients. However, no disease progression was seen after diltiazem therapy. These results may encourage heart transplantation in Japan.

Adult↗