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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 289 records · Page 16Linked to original sources
PubMed1998

Citrate promotes attachment of Prevotella nigrescens (intermedia) ATCC 25261 to hydroxyapatite.

Large quantities of Prevotella nigrescens (intermedia) ATCC 25261 (P. nigrescens) cells adhere to hydroxyapatite (HA) treated with citrate, but do not adhere experimental pellicle prepared from human whole saliva. To determine the nature of the citrate responsible for promoting P. nigrescens cell adhesion, the duration and frequency of citrate treatment of HA and the inhibitory effect of other carboxylates were tested. The citrate rapidly adhered to HA beads in less than 15 min. With a lower concentration (0.4 mM) of citrate, four treatments of HA were required to promote the maximum adherence to P. nigrescens cells. Citrate-enhanced P. nigrescens cell adherence to HA beads was also inhibited in the presence of cis-aconitate, oxaloacetate and oxalsuccinate. It was also found that P. nigrescens cells heated to 65 degrees C or higher for 5 min could no longer become attached to citrate-treated HA. These data suggest that citrate is one of the essential factors responsible for P. nigrescens cell attachment to apatitic surfaces, and that P. nigrescens' adhesion to citrate is extremely heat-sensitive.

Aconitic Acid↗
PubMed1998

Analysis of clonality in human endometriotic cysts based on evaluation of X chromosome inactivation in archival formalin-fixed, paraffin-embedded tissue.

The clonality of epithelial cells in ovarian endometriotic cysts was evaluated on the basis of a polymorphism of the X-linked phosphoglycerate kinase gene (PGK). The problems associated with clonality analysis of DNA samples extracted from archival formalin-fixed, paraffin-embedded tissue were addressed with the use of newly designed primers and a modified stepdown program for PCR amplification. The method relies on digestion of DNA with the methylation-sensitive restriction enzyme SnaBI, PCR amplification of PGK, and detection of a BstXI polymorphism. With this approach, only the inactive (methylated) PGK allele is selectively amplified by PCR. A total of 25 epithelial cells in endometriotic cysts and 25 matched normal ovarian stromal tissue specimens were analyzed. All of the control tissue samples yielded PCR products, with 11 of the 25 samples found to be heterozygous for the BstXI polymorphism. Ten of the 25 epithelial cells in endometriosis specimens were informative at this locus, and all of these 10 were shown to be monoclonal on the basis of PGK methylation. The results indicate that this new method of clonal analysis with archival formalin-fixed tissue is reliable and confirm that endometriotic cysts are monoclonal in origin.

Base Sequence↗
PubMed1998

Effects of soy protein on the morphology of ileum and the ultrastructure of liver cells in adult mice.

The influences of soy protein on the morphology of ileum and on the ultrastructure of liver were studied. Adult male mice of the Crj: CD-1 (ICR) strain were fed a semisynthetic diet containing casein or soy protein for three weeks. Villus heights in ileum from the mice fed soy protein diet were significantly greater than those fed casein diet. There were evident ultrastructural differences in the liver cells between the mice fed the two diets. Many lipid droplets from the mice fed the casein diet were larger than those fed the soy protein diet. The maximum diameter of lipid droplet per liver cell in the soy protein diet group was smaller than that in the casein diet group (p < 0.01). These results suggest that soy protein and casein affect the ultrastructure of liver and the morphology of ileum in different ways.

Animal Nutritional Physiological Phenomena↗
PubMed1998

Effect of beta-sitosterol on ultrastructure of liver cells in young and aged mice.

The effects of beta-sitosterol on liver ultrastructure were studied using young and aged male mice. Both groups of mice were fed a beta-sitosterol or a control diet. The beta-sitosterol diet contained 1% beta-sitosterol. Ultrastructural differences in the liver cells were evident between two groups fed the two diets. The number of peroxisomes was significantly greater in the liver cells of both young and aged mice fed the beta-sitosterol diet than in those fed the control diet. There were also significant differences in the maximum length of lipid droplets between the young and aged mice fed the beta-sitosterol diet. These results suggest that beta-sitosterol affects liver ultrastructure, and that some ultrastructural differences in liver cells exist between young and aged mice fed the beta-sitosterol diets.

Aging↗
PubMed1998

[Internalized norms and social norms relating to negative health behaviors. The relationship of sociodemographic characteristics and reference groups].

So-called "negative health behaviors" (e.g. smoking, excessive eating/drinking), which are related to morbidity and mortality, are generally well known to the public. However there are many who undertake negative health behaviors despite knowing of their negative health effects. Using a mail survey of subjects aged 25 to 54, we examined reasons and justifications for engaging in negative health behaviors and their related factors from the lay person's perspective. Concerning the reasons for negative health behaviors, we hypothesized seven concepts (work priority, group harmony priority, the contribution to relaxation, tools for communication, prior orientation focused on the present, individualistic priority, and appearance), and devised multiple questions for each concept. The results are as follows. 1. Compared to females, males tended to support of the five concepts about the internalized norms concerned with negative health behaviors (e.g. the tendency of each individual to approve or disapprove of the reasons for negative health behaviors). In females, the younger generation and those that were married expressed more support than the older and the unmarried. There were differences in males according to occupation. 2. Concerning which reference groups had the largest influence on the social norms concerned with negative health behaviors (e.g. the perceptions as to what degree a group regards the reasons about negative health behaviors as desirable), most perceived that the "office" and "friends" groups would be more supportive of reasons for negative health behaviors than the "family" groups. 3. The health behaviors, which correlated with the internalized norms or the social norms concerned with negative health behaviors, were eating breakfast, smoking, and drinking (frequency and amount). In particular, drinking behavior was influenced most by the internalized norms and the social norms.

Adult↗
PubMed1998

HRA model for hypercholesterolemia based on a longitudinal health database.

To evaluate the risk factors for hypercholesterolemia, we examined 4,371 subjects (3,207 males and 1,164 females) who received medical checkups more than twice at an AMHTS in Tokyo during the period from 1976 through 1991; and whose serum total cholesterol was under 250 mg/dl. The mean follow-up duration was 6.6 years. A self-registering questionnaire was administered at the time of the health checkup. The endpoint of this study was the onset of hypercholesterolemia when the level of serum total cholesterol was 250 mg/dl and over. We compared two prognosis groups (normal and hypercholesterol) in terms of age, examination findings and lifestyle. After assessing each variable, we employed Cox's proportional hazards model analysis to determine the factors related to the occurrence of hypercholesterolemia. According to proportional hazards model analysis, total cholesterol, triglyceride and smoking at the beginning, and hypertension during the observation period were selected in males; and total cholesterol at the beginning and age were selected in females to determine the factors related to the occurrence of hypercholesterolemia.

Adult↗
PubMed1998

Elimination of inter-institutional discrepancies in health check-up results: standardization of diagnostic decision level and uniformity of examination data.

In Japan, more people are taking AMHTS and the number of medical institutions where it is provided is also increasing. AMHTS is expected to continue to expand in scope and importance from now on. People do not necessarily take AMHTS at the same medical institutions year after year. For AMHTS to be truly useful from the viewpoint of preventive medicine and be able to continue its development, it is imperative that the level of diagnosis be standardized and the compatibility of examination data be established among different institutions. The Japan Society of MHTS is conducting pilot studies of reversed quality control (RQC) as part of its activities with the aim of clearly understanding inter-institution gaps regarding AMHTS and to establish uniformity in examination data.

Humans↗
PubMed1998

[Treatment of mediastinal infection by continuous closed irrigation with an antibiotic solution in a new bone baby].

The patient was a three-week-old girl. Four days after thoracic surgery, mild fever developed, and turbid fluid was drained from the incision. Culture of the discharge showed Pseudomonas aeruginosa and Serratia marcescens. Débridement was immediately performed and continuous closed irrigation with an antibiotic solution started and maintained for 17 days. During this period, the upper half of the body was elevated. Ten days after irrigation started culture of the drainage fluid became negative. We emphasize early diagnosis, and the usefulness of continuous closed irrigation with an antibiotic solution in neonates.

Drug Therapy, Combination↗
PubMed1997

Scleraxis messenger ribonucleic acid is expressed in C2C12 myoblasts and its level is down-regulated by bone morphogenetic protein-2 (BMP2).

We examined the mRNA expression of scleraxis, a non-myogenic helix-loop-helix type transcription factor in C2C12 myogenic cells. Scleraxis mRNA has been shown to be expressed in sclerotome and perichondrium of the embryos. We found that C2C12 cells express 1.2 kb scleraxis mRNA constitutively. Since BMP was reported to induce ectopic bone formation when implanted in muscle, we examined the effects of BMP on scleraxis expression. Scleraxis mRNA expression in C2C12 cells was suppressed by the treatment with BMP2. This suppression was observed at 200 ng/ml but not at the lower concentrations. BMP2 treatment suppressed scleraxis mRNA level within 24 h and lasted at least up to 48 h. Electrophoresis mobility shift assay showed that the proteins in the crude nuclear extracts prepared from C2C12 cells bound to an Scx-E-box sequence, CATGTG, which is preferentially recognized by scleraxis. This binding was competed out by 100-fold molar excess of cold Scx-E-box sequence but not by the one with mutations in the E-box. This band was supershifted by the addition of antiserum raised against scleraxis. BMP2 treatment suppressed the Scx-E binding activity in C2C12 cells. This suppression of the Scx-E-box binding activity was in parallel to the BMP2 suppression of the transcriptional activity of the Scx-E-CAT reporter gene transfected into C2C12 cells. These data indicated that although the default pathway for C2C12 cells is to differentiate into muscle cells, these cells do express non-myogenic transcription factor, scleraxis, whose expression is suppressed by BMP2.

Animals↗
PubMed1997

FUT-175, a synthetic inhibitor of the complement pathway, protects against the inactivation of infectious retroviruses by human serum.

Serum-induced inactivation of retroviruses is the most critical limitation for in vivo gene transfer therapy. To solve this problem, we searched for reagents that protect retroviruses from inactivation. The effects of the protease inhibitors FOY-007 and FOY-305 and of an inhibitor of the complement pathway FUT-175, all of which have been used clinically, were investigated. All of these agents protected against the inactivation of retroviruses by human serum, with 1 microM FUT-175 providing the most effective protection. Thus, the co-administration of FUT-175 with retroviruses may make retrovirus-mediated in vivo gene transfer feasible for the treatment of patients. FUT-175 dose-dependently inhibited the classical pathway of complement in a hemolysis protection assay of sensitized sheep erythrocytes with guinea pig serum or by cell-lysis assay of mouse fibroblasts with human serum. However, increasing the FUT-175 concentration by 10-fold (10 microM) did not produce further protection against retroviral inactivation in most human sera. There was also no correlation between the serum-induced inactivation of retroviruses and either the amount of anti-alpha-galactosyl (anti-alpha-Gal) antibody or the complement activity in human serum. These results suggest that retroviruses are not inactivated by utilizing the same pathway leading to cell lysis by the classical complement system.

3T3 Cells↗
PubMed1997

Localized near-infrared spectroscopy and functional optical imaging of brain activity.

Changes in cerebral blood flow (CBF) and cerebral metabolic rates (CMRO2) have been used as indices for changes in neuronal activity. Near-infrared spectroscopy (NIRS) can also measure cerebral haemodynamics and metabolic changes, enabling the possible use of multichannel recording of NIRS for functional optical imaging of human brain activity. Spatio-temporal variations of brain regions were demonstrated during various mental tasks. Non-synchronous behaviour of cerebral haemodynamics during the neuronal activation was observed. Gender- and handedness-dependent lateralization of the function between right and left hemispheres was demonstrated by simultaneous measurement using two NIR instruments during the mirror-drawing task. A lack of interhemispheric integration was observed with schizophrenic patients. These observations suggest an application for NIRS in psychiatric disease management, as an addition to clinical monitoring at the bedside. A time resolved 64-channel optical imaging system was constructed. This consisted of three picosecond laser diodes and 64 channels of TAC and CFD systems. Image reconstruction for phantom model systems was performed. Time-resolved quantitative optical imaging will become real in the very near future.

Adult↗
PubMed1997

Changes in right ventricular volume in early human neonates.

To evaluate changes in the right ventricular volume in early human neonates, twenty fullterm infants were examined at 2, 24 and 120 h of age by two-dimensional echocardiography. End-diastolic and end-systolic right ventricular volumes (RVEDV and RVESV, respectively) were calculated with a computer system based on the bi-plane Simpson's rule using the apical four chamber and parasternal short axis views. Then right ventricular stroke volume (RVSV), ejection fraction (RVEF), and the mean normalized systolic ejection rate were obtained. The inner diameter of the ductus arteriosus was also measured simultaneously. RVEDV increased significantly by 24 h of age, but remained constant thereafter. RVESV remained virtually unchanged from 2 to 120 h, resulting in a significant increase (36%) of RVSV at 24 h compared with that at 2 h. The mean normalized systolic ejection rate remained unchanged. There was a good correlation between RVEDV and RVSV (r = 0.83). All ductus arteriosus except three narrow ones was closed by 24 h of age. In conclusion, at 24 h of age, the significantly increased RVEDV was closely related to the increased RVSV, which might be induced by increased volume load to the right ventricle because of the closure of the ductus arteriosus.

Ductus Arteriosus↗
PubMed1997

New assay for glycated lipoproteins by high-performance liquid chromatography.

We developed an automated analytic system for glycated lipoprotein using high-performance liquid chromatography (HPLC) with an affinity boronate column and a gel permeation column. This system can measure glycated lipoprotein (glycated LDL and glycated HDL) in a small (5 microliters) sample of serum in a short time (40 min/sample). Recovery with this system was 92.1%. Therefore a large number of samples can be measured in clinical use. The system should contribute to an elucidation of the role of glycated lipoprotein in atherosclerosis.

Chromatography, High Pressure Liquid↗
PubMed1997

Synthesis and structure-activity relationships of carboxylated chalcones: a novel series of CysLT1 (LTD4) receptor antagonists.

The synthesis and CysLT1 antagonistic activities of a new series of 2-, 3-, and 4-(2-quinolinylmethoxy)- and 3- and 4-[2-(2-quinolinyl)ethenyl]-substituted, 2'-, 3'-, 4'-, or 5'-carboxylated chalcones are described. Structure-activity relationship studies indicate a preference for the presence of a negatively charged (acidic) moiety, although in some cases nitrile or ester analogues also exhibit moderate activity. The quinoline moiety may be substituted at either the 3- or the 4-position. Replacement of this heterocycle by other aromatic groups results in compounds with comparable affinities [2-(7-chloroquinoline), 1-(1-methyl-2-benzimidazole), or 1-(2-benzothiazole)] or substantially lower activities [1-(1-ethoxyethyl)-2-benzimidazole, 2-naphthyl, or phenyl]. The quinoline and chalcone moieties may be connected by either an ethenyl or a methoxy spacer. The acidic moiety at the chalcone B ring may be attached to the 2'-, 3'-, 4'-, or 5'-position, for both the 3- and 4-substituted chalcones. There are no general patterns to specify which substitution positions gave the most potent compounds. The series contains several potent CysLT1 receptor antagonists, with K(D) values approaching the nanomolar range, as measured by the displacement of [3H]LTD4 from guinea pig lung membranes. Antagonism of LTD4-induced contraction of guinea pig ileum, the inhibition of antigen-induced contraction of guinea pig trachea in vitro, and the inhibition of LTD4-induced increase of vascular permeability in vivo are determined for chalcones with high CysLT1 receptor affinities (K(D) values below 0.1 microM). 2'-Hydroxy-4-(2-quinolinylmethoxy)-5'-(5-tetrazolyl)chalcone (14, VUF 4819) showed good activity in both in vitro and in vivo assays and has been selected for further evaluation.

Animals↗
PubMed1997

Targeted killing of migrating glioma cells by injection of HTK-modified glioma cells.

The "bystander effect" describes the killing of nearby unmodified cells and herpes simplex thymidine kinase (HTK)-transduced cells by ganciclovir (GCV) treatment. This effect is thought to be produced by contact between these cells. In this study, we showed that injected glioma cells migrated rapidly to a place distant from the injection point whereas injected virus-producing fibroblast cells did not migrate in a murine brain model. Moreover, the initially injected glioma cells and glioma cells injected at a later time mix very well, even at a place distant from the injection point. This suggested that glioma cells migrating after injection could be targeted by HTK-modified glioma cells introduced in a second injection and be killed together by GCV treatment. Therefore, we injected HTK-modified glioma cells 3 days after injection of wild glioma cells to investigate whether wild-type glioma cells that migrated to a place distant from the injection point could also be killed by GCV treatment. Tumor growth was suppressed after the GCV treatment. Suppression of tumor growth of wild glioma cells is not solely mediated by the immune response, which may be triggered by the killing of HTK-modified glioma cells with GCV, because inoculation of HTK-modified glioma to the contralateral side followed by GCV treatment did not cure the initial wild glioma. Moreover, the migration of the second inoculum of glioma cells is necessary for effective killing, because early administration of GCV resulted in insufficient killing.

Animals↗