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Biomedical subjects

E Tanaka

Publications and source records attributed to E Tanaka.

At least 469 records · Page 26Linked to original sources
PubMed1990

Association between mechanical stress and bone remodeling.

Stress patterns and levels were analyzed by use of the three-dimensional finite element method. Three-dimensional models were constructed for the human upper central incisor (1205 nodes and 920 elements) and the sheep metacarpus (240 nodes and 128 elements). Orthodontic and orthopedic forces were applied to the tooth and the bone, simulating orthodontic tooth movement and experimental loading test for the bone. Three principal stresses were determined in the alveolar bone and the sheep long bone. The following results were obtained. 1. Stress distributions in the lateral alveolar bone were similar to those with bone deformation from cantilever bending mode. On the medial surface of the alveolar bone, a bending stress was observed, however, remaining stresses exhibited changes corresponding to those in the PDL produced by tipping displacement of the tooth. 2. In the sheep long bone, tensile and compressive stresses were induced on the dorsal and volar sides, respectively. The magnitude of stresses was greatest at the mid-diaphyseal region. Compressive and tensile stresses were related with bone resorption and apposition. The magnitude of principal stresses was almost proportional to dimensional changes of the bone at the mid-diaphyseal region. Bone remodeling in the long bone is related with mechanical stress, principal stress in particular, indicating that remodeling of the alveolar bone may be induced by application of orthodontic force in addition to conventional change of the bone adjacent to the PDL. Thus, it is shown that mechanical stress in living structures may be a trigger to induce biological remodeling of bones.

Alveolar Process↗
PubMed1990

[An evaluation of 3-dimensional position of mandibular condyle to glenoid fossa using tomogram: an analytical technique and its clinical application].

In recent years, temporomandibular disorder (TMD) is occasionally found among orthodontic patients and has become a great concern in orthodontics. From this point of view, a certain technique has been hopefully anticipated for diagnosis and treatment planning. The purpose of this study was to develop a new method for evaluating three-dimensional position of the mandibular condyle relative to the glenoid fossa and also to investigate its clinical application. Seven-layered tomograms were taken and contours of the condyle and glenoid fossa were traced on an acetate paper. These contours were entered into a personal computer by use of a digitizer and were equally divided into 9 parts for the condyle and 15 parts for the glenoid fossa, consisting of 10 and 16 points on the contours of condyle and glenoid fossa. Three-dimensional configuration of the TMJ was thus constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and the glenoid fossa (CGFD) was then calculated along a perpendicular line to center of gravity of a triangle on the condyle. For evaluating the position of the condyle to the glenoid fossa easily in a three dimensional space, surface of the condyle was divided into five areas, i.e. anterior, posterior, middle, lateral and medial areas. In order to investigate whether or not the CGFD is accurate enough to identify the distance between surface of the condyle and glenoid fossa, a model of hemi-spherical solid shell was made, of which the thickness is 3.0 mm. Tomograms of the model were taken to analyze the thickness. Direct measurement of the same area was also made by calipers. Two means were approximately 3.0 mm, which is the thickness itself and no significant differences were indicated at 5% level of confidence. The present technique was applied to diagnosis of an orthodontic patient with painful clicking as TMD. The analyzed CGFDs were coincident with clinical symptom. It is shown that the present approach provides an availability and a possibility to evaluate positional relationship between the mandibular condyle and the glenoid fossa of patients with TMDs.

Humans↗
PubMed1990

[Changes of three types in the secretory systems present in the rat submandibular glands during aging].

Changes of the three types, termed here as alpha, beta and gamma, in the secretory functions present in the submandibular glands (SMG) of male rats were observed throughout almost all animal lives from 2 weeks to 24 months of age, by measuring changes of the wet weights of the SMG, salivary volumes secreted, the concentrations of protein, calcium and inorganic phosphate, and the types of proteins secreted in response to alpha-methylnoradrenaline (alpha-mNA) for the alpha-type, isoproterenol (IPR) for the beta-type and clonidine (Clonid) for the gamma-type, volumetrically, colorimetrically, atomic absorption-pectrophotometrically and isoelectric focusing electrophoretically. The molecular weight, isoelectric point and some posttranslational variations of a purified protein were elucidated by SDS-polyacrylamide gel electrophoresis (PhastSystem), isoelectric focusing electrophoresis (IEF, PhastSystem) on gradient pH 3.5 to 5 gels and neuraminidase or alkaline phosphatase treatment. The localization in the SMG, the inhibitory effects on the BrdU incorporation of the cultured thymocytes and the adhesive properties to the acrylic resin plate of this antigen were also analyzed by the indirect immunofluorescence, IEF and protein detection methods. The wet weights of the SMG were substantially increased up to 3.5 months of age with a positive correlation to body weight, but thereafter it reached the plateau level up to 24 months of age, somewhat different from changes of body weight. The salivary volumes as well as the amounts of protein secreted in response to alpha-mNA, IPR and Clonid were positively correlated to the wet weights of the SMG throughout the animal life. The concentration of calcium in the three types of secretions was positively correlated to the protein concentration, whereas the concentration of inorganic phosphate was tended to be reversely correlated to the salivary flow rate with some exceptions throughout the animal life. The gamma-type of proteins was not greatly changed, whereas the alpha- and beta-types of proteins were greatly changed in some proteins quantitatively or qualitatively throughout the animal life.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1990

[Locomotor activity and urinary excretion of orthocresol in rats exposed to toluene].

To clarify the effect of toluene on behavior, and to evaluate urinary orthocresol excretion as an indicator of toluene exposure and locomotor activity, we have investigated the urinary orthocresol excretion and levels of locomotor activity in rats exposed to 0-3000 ppm of toluene intermittently for 2 hours. The levels of locomotor activity were measured by a laboratory animal activity measuring apparatus (ANIMEX-III). Exposure of adult male rats to more than 1000 ppm (v/v) of toluene caused an elevation of the urinary orthocresol excretion and a good correlation was noted between the amount of toluene in the air and the urinary orthocresol excretion. Exposure to over 2000 ppm of toluene suppressed the level of locomotor activity, and there was a good correlation between the level of locomotor activity and the urinary orthocresol excretion. Further, rats exposed to 3000 ppm toluene showed elevated levels of locomotor activity during a 10-hour period after exposure. These patterns of urinary orthocresol excretion and the levels of locomotor activity remained unchanged even when rats were exposed to 3000 ppm of toluene intermittently over a 4-day period.

Animals↗
PubMed1990

Inelastic constitutive modeling for blood vessels based on viscoplasticity.

A transversely isotropic inelastic constitutive model based on the concept of internal variable theories is proposed to describe the hysteresis loops of blood vessels under cyclic loading by taking account of loading path dependence as well as loading rate dependence. The comparison of the numerical results with literature shows that the present model can describe the anisotropic inelastic mechanical behavior well.

Animals↗
PubMed1990

Initial accumulation of paraquat in the heart leading to acute death.

When a large amount of paraquat (364 mg/kg) which caused death in several hours was orally ingested in rats, the herbicide concentration in blood continued to increase until the animal died. Furthermore, there was a correlation between the paraquat concentration in the blood, heart, liver and adrenal gland and the survival time. While the paraquat concentration in the heart had the most evident correlation in those tissues (r = -0.962), there was no correlation between the paraquat concentration and survival time in the lung or kidney. ECG of the rats which died in the early stages showed severe damage in the heart. It was found by histopathological studies that edema, congestion and hemorrhage occurred in the myocardium of rats that had died shortly after administration of a large amount of paraquat (364 mg/kg). These results suggest that a rapid accumulation of paraquat into the heart in the early stages may play an important role in the cause of acute death.

Animals↗
PubMed1989

The complete nucleotide sequence of the glutamine synthetase gene (glnA) of Bacillus subtilis.

The glutamine synthetase (GS) gene from Bacillus subtilis PCI 219 was cloned in Escherichia coli using the vector pBR329. A plasmid, pSGS2, was isolated from a glnA+ transformant and the cloned GS gene was found to be located in a 3.6 kb DNA fragment. The nucleotide sequence of a 1.8 kb segment encoding the GS was determined. This segment showed an open reading frame which would encode a polypeptide of 444 amino acids. The amino acid sequence of this GS gene product has higher homology with that of the Clostridium acetobutylicum GS than that of the E. coli GS.

Amino Acid Sequence↗
PubMed1989

Seroepidemiology of hepatitis A, B, and D viruses and human T-lymphocyte tropic viruses in Japanese drug abusers.

To evaluate the prevalence of hepatitis virus markers and human T-cell lymphotropic virus infections among drug abusers in Japan, serum samples were collected from 91 male drug abusers at the Shinshu University Hospital and the rehabilitation facility in Matsumoto and from 519 healthy male blood donors as controls. Sera were tested for antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to hepatitis B core antigen (anti-HBc), immunoglobulin M anti-HBc (IgM anti-HBc), antibody to hepatitis D virus (anti-HDV), antibody to HTLV type 1 (anti-HTLV 1), and antibody to human immunodeficiency virus (anti-HIV). The prevalence of anti-HAV was 13.2% in drug abusers and 10.8% in controls (not significant). The prevalences of HBsAg, anti-HBs, anti-HBc and exposure rate to hepatitis B virus (HBV) were 4.4%, 24.2%, 31.9%, and 35.2%, respectively, in drug abusers and 0.8%, 6.7%, 9.6%, and 9.6% in controls. The exposure rate to HBV was significantly different (P less than 0.001). IgM anti-HBc and anti-HDV were not detected in any sera. Anti-HTLV I was detected in three drug abusers (3.3%) and in one (0.2%) of the controls (P less than 0.01). All sera were negative for anti-HIV in all subjects. Infection with HBV and HTLV I is more common among drug abusers than in the general population of blood donors in Japan.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Patch clamp experiments on nicotinic acetylcholine receptor-ion channels in bullfrog sympathetic ganglion cells.

Nicotinic acetylcholine-receptor ion channels (AChR channels) were studied in bullfrog sympathetic ganglion cells cultured for 1 day to 3 weeks, using a patch clamp technique. Microsuperfusion of ACh (2-10 microM) to the ganglion cell under the whole cell clamp produced an inward current at membrane potentials negative to -60 mV, which had a fast onset and decay. This rapid ACh-induced current was accompanied by a large current fluctuation, decreased and increased in amplitude by membrane depolarization and hyperpolarization, respectively, and blocked by d-tubocurarine. Thus, this current must be induced by the nicotinic action of ACh, but not by a muscarinic effect to activate a slow cation-selective current. At depolarized levels more than -50 mV, ACh induced an additional inward current which was slow in time course, accompanied by no or decreased current fluctuation and increased in amplitude by membrane depolarization. Accordingly, this slow ACh-induced current could result from the suppression of a voltage-dependent K+ current (M-current: Brown and Adams 1980) by the muscarinic action of ACh. Fluctuation analysis of the rapid ACh-induced current at potentials negative to -50 mV revealed the elementary conductance of 14 pS and a power spectral density distribution of the double Lorentzian function which yielded the time constants of 5.4 and 62.5 ms at -60 to -80 mV. The variance of either component was independent of the mean current.

Acetylcholine↗
PubMed1989

Comparison of trimethadione and antipyrine as indicators of oxidative drug metabolizing capacity in man.

Ten healthy male volunteers were given trimethadione (TMO) 4 mg/kg and antipyrine (AP) 500 mg alone or concomitantly to determine whether the metabolism of the drugs was mediated by the same or closely related forms of cytochrome P-450. Whether administered alone or together the clearance (CL) and half-life (t 1/2) of TMO and AP were the same, and there was a good correlation between the CL and t 1/2 of TMO and AP (alone r = 0.755 and 0.623, respectively; coadministered r = 0.771 and 0.503, respectively). Excretion of AP and its main metabolite and the clearance for production of AP metabolites after AP was administered alone were not significantly different when TMO and AP were taken together. When the two drugs were administered alone or coadministered, the correlation between the CL of TMO and the excretion of 3-hydroxymethyl-3-norantipyrine (NORA) was close (alone r = 0.734, coadministered r = 0.749). The correlation between the CL of TMO and CLm of NORA when TMO and AP were given alone or concomitantly was 0.762 and 0.772, respectively. The findings suggest that TMO metabolism and the formation of NORA in healthy subjects are mediated by a closely related form(s) of the cytochrome P-450 system.

Adult↗
PubMed1989

Treatment of chronic non-A non-B hepatitis with human interferon beta: a preliminary study.

Twenty-four patients with chronic non-A non-B hepatitis were randomly assigned to receive either human fibroblast interferon (HuIFN-beta) at doses of 1 or 3 million international units (MIU) per day for 4 or 12 weeks (12 patients) or to receive no therapy (12 patients), and were then compared with 5 patients with chronic type B hepatitis who were treated with HuIFN-beta. Elevated serum aminotransferase levels decreased more rapidly during the treatment of chronic non-A non-B hepatitis than of chronic hepatitis B. Variations in serum aminotransferases were not observed in any of the untreated chronic non-A non-B hepatitis patients. In 3 of the 9 patients with chronic non-A non-B hepatitis who responded to HuIFN-beta therapy, serum aminotransferase levels remained normal 15, 21 and 31 months after therapy was discontinued; liver biopsy specimens obtained after therapy from 2 patients showed marked histological improvement. In the six other patients aminotransferase activity levels became again elevated following cessation of interferon therapy. No response to HuIFN-beta was seen in the remaining 3 patients with chronic non-A non-B hepatitis.

Adult↗
PubMed1989

Nucleotide sequence of the glutamine synthetase gene (glnA) and its upstream region from Bacillus cereus.

We have determined the complete nucleotide sequence of a 2.4 kb chromosomal EcoT22I-NspV fragment, containing the Bacillus cereus glnA gene (structural gene of glutamine synthetase). The deduced amino acid sequence indicates that the glutamine synthetase subunit consists of 444 amino acid residues (50,063 Da). Comparisons are made with reported amino acid sequences of glutamine synthetases from other bacteria. Upstrem of glnA we found an open reading frame of 129 codons (ORF129) preceded by the consensus sequence for a typical promoter. Maxicell experiments showed two polypeptide bands, with molecular weights in good agreement with that of glutamine synthetase and that of ORF129, in addition to vector-coded protein. It is possible that the product of this open reading frame upstream of glnA has a regulatory role in glutamine synthetase expression.

Amino Acid Sequence↗
PubMed1989

The effect of roxatidine acetate and cimetidine on hepatic drug clearance assessed by simultaneous administration of three model substrates.

The effect of pretreatment for 7 days with either roxatidine acetate 75 mg twice daily or cimetidine 200 mg four times daily on the kinetics of antipyrine (AP), trimethadione (TMO) and indocyanine green (ICG) was studied in seven healthy, male, nonsmoking subjects. After pretreatment with cimetidine, the plasma clearances (CL) of AP and TMO were significantly lower and the elimination half-life (t1/2) of AP was significantly increased. The volumes of distribution (V) of AP and TMO were not affected. After roxatidine acetate, the pharmacokinetics of AP and TMO were unchanged. The cumulative renal excretion (% dose) and formation clearance of 3-hydroxymethyl-3-nor-antipyrine (NORA) were lowered by cimetidine treatment, but not following the administration of roxatidine acetate. ICG clearance was not changed significantly by either pretreatment. The results of this study show that roxatidine acetate does not impair the metabolism of three model substrates used to assess hepatic drug clearance.

Adult↗
PubMed1989

The metabolism and excretion of trimethadione in patients with percutaneous transhepatic biliary drainage and renal dysfunction.

The metabolism and excretion of trimethadione (TMO) following an oral dose of 4 mg/kg has been examined in patients with percutaneous transhepatic biliary drainage (PTBD) and renal dysfunction. Biliary excretion as the total amount of TMO and its metabolite, dimethadione (DMO) was 2.0% of the dose during 0 to 48 h after TMO administration in patients with PTBD. Total urinary excretion (0-48 h) was 2.8% and 3.0% of the dose in healthy volunteers and patients with renal dysfunction, respectively. The serum DMO/TMO ratio at 4 h after oral dosing in patients of PTBD and renal dysfunction was not significantly changed in comparison with the ratio reported previously in healthy volunteers. The elimination half-life of TMO was also not altered in patients with PTBD in comparison with that reported previously in volunteers. These results suggest that metabolism and urinary and biliary excretion of TMO are not changed in patients with PTBD and renal dysfunction.

Adult↗