Biomedical subjects

T Ohyama

Publications and source records attributed to T Ohyama.

At least 91 records · Page 5Linked to original sources

PubMed2000

Analysis of urgent colonoscopy for lower gastrointestinal tract bleeding.

BACKGROUND: Three hundred and forty-five patients who underwent urgent colonoscopy for acute hematochezia during the past 20 years (from 1976 to 1995) were retrospectively analyzed. METHODS: Urgent colonoscopy was defined as endoscopy performed within 24 h after a bleeding episode. Preparation was initially minimal with a water or glycerine enema. Recently, however, polyethylene glycol is used. RESULTS: The overall diagnostic accuracy for bleeding site detection was 89.1% (307 cases). Successful insertion was made to the ileocecal region in 193 cases (55.9%). The disease most frequently discoverd by urgent colonoscopy was transient ischemic colitis (62 cases). Negative urgent colonoscopy specimens (18 cases) were later diagnosed by other methods as being small intestinal bleeding foci. In 10 cases, initial colonoscopy failed to detect the bleeding foci. Endoscopic hemostasis was performed in 48 cases. Permanent hemostasis succeeded in 32 cases (66.7%). Complications of urgent colonoscopy were fever after the examination (22 cases) and hypotension during endoscopy (7 cases). CONCLUSION: Urgent colonoscopy is considered to be a safe and useful examination for acute lower gastrointestinal bleeding and hemostasis.

Acute Disease↗

PubMed2000

Effects of chronic administration of sibutramine on body weight, food intake and motor activity in neonatally monosodium glutamate-treated obese female rats: relationship of antiobesity effect with monoamines.

When the hypothalamic ventromedial nucleus and arcuate nucleus were destroyed in rats by treatment with monosodium glutamate in the neonatal stage, increase in the Lee index (body weight 1/3/body length) and in retroperitoneal fat as well as decreases in spontaneous motor activity, food consumption and growth hormone secretion function associated with hypothalamic low body length obesity (monosodium glutamate-treated obesity; MSG-OB) were observed as these rats grew. Treatment with sibutramine at 3 and 10 mg/kg p.o. once a day continuously for 14 days improved these parameters, and the degree of improvement was dose related. The plasma lipid values in MSG-OB rats, which were the same as those in normal rats, were decreased by consecutive administration of sibutramine. Levels of hypothalamic monoamines (MAs) such as norepinephrine, 5-HT (serotonin) and dopamine and their metabolites DOPAC, HVA and 5-HIAA were decreased in MSG-OB rats, and further decrease in them, though slight, was observed with consecutive daily administration of sibutramine, probably as a result of the feedback attributable to an increase in MA in synapses caused by inhibition of MA uptake by sibutramine. These results suggest that sibutramine can activate the MA nervous system by MA uptake inhibition in regions of the brain such as the lateral hypothalamic area and the paraventricular nucleus, which control food intake and sympathetic nerve activity, and the nigrostriatal area related to the extrapyramidal motor system, and thereby exhibit anti-obesity effects in the MSG-OB rat.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2000

Arborcandins A, B, C, D, E and F, novel 1,3-beta-glucan synthase inhibitors: production and biological activity.

Arborcandins A, B, C, D, E and F, which possess potent 1,3-beta-glucan synthase inhibitory activity, were isolated from the culture broth of a filamentous fungus, strain SANK 17397. Arborcandins are novel cyclic peptides, that are structurally different from known glucan synthase inhibitors such as echinocandins. The 1,3-beta-glucan synthases of Candida albicans and Aspergillus fumigatus were inhibited by arborcandins with IC50 ranging from 0.012 to 3 microg/ml. The apparent Ki value of arborcandin C for C. albicans and A. fumigatus were 0.12 microM and 0.016 microM, respectively. The inhibition against these two 1,3-beta-glucan synthases by arborcandin C was noncompetitive. These compounds exhibited potent fungicidal activity against Candida spp. with MIC ranging from 0.25 to 8 microg/ml. The growth of A. fumigatus was suppressed by arborcandins with concentrations ranging from 0.063 to 4 microg/ml.

Anti-Bacterial Agents↗

PubMed2000

Effect of dopaminergic drugs on the reserpine-induced lowering of hippocampal theta wave frequency in rats.

The effects of dopaminergic drugs on the lowering of hippocampal theta wave frequency induced by reserpine 1 mg/kg s.c. were examined. Sibutramine (monoamine reuptake inhibitor) 10 mg/kg p.o., methamphetamine (monoamine releaser) 1 mg/kg, quinpirole (dopamine D2 receptor agonist) 10 mg/kg i.p., and SKF 38393 (dopamine D1 receptor agonist) 10 mg/kg i.p. each antagonized the reserpine-induced lowering of hippocampal theta wave frequency in rats. Moreover, the combined administration of SKF 38393 1 mg/kg i.p. and quinpirole 1 mg/kg i.p. synergistically antagonized a reserpine-induced lowering of this frequency. Dosulepin, amitriptyline, and desipramine, which are weak inhibitors of dopamine reuptake, each had little effect on the reserpine-induced lowering of theta wave frequency at a dose of 40 mg/kg p.o. Furthermore, atropine (muscarinic anticholinergic drug) 20 mg/kg p.o. decreased theta wave power in the low-frequency range following a shift to the lower range by reserpine. A positive correlation was observed for each of the above drugs between a reversal of reserpine-induced lowering of theta wave frequency and a reversal of impairment of reserpine-induced conditioned avoidance responses (ACAR) in rats. These results suggest that the reserpine-induced lowering of hippocampal theta wave frequency plays a role in the impairment of reserpine-induced ACAR, and that dopamine D1 and D2 receptors play important roles in antagonizing this lowering of frequency.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed2000

The vibration analysis of obturator framework designs.

The purpose of this study was to analyze the vibration of obturator framework designs and investigate the vibration effects of connecting parts of the components. Four designs of maxillary obturator framework were used in this study: a partial palatal plate with continuous bar (A), with a part of continuous bar (B), without continuous bar (C) and without continuous bar and indirect retainer (D). In order to investigate the vibration of each framework (total) and some component parts, the measurement points of the retentive parts were divided into 3 groups; anterior, middle and posterior. The framework was activated by a vibration generator. The vibration of each measurement point was detected with a laser doppler vibrometer. The frequency response signals were conducted by an FFT Analyzer between 220-2000 Hz. The maximum displacement (MDP) and the decay rate (DR) of the vibration were analyzed statistically by ANOVA and Fisher's PLSD (p<0.05). The result showed that in the posterior group, MDP of D was higher than those of A, B and C. Regarding the anterior, middle and total group, the DR of D were lower than A, B and C. It was suggested that D might be clinically unfavorable.

Analysis of Variance↗

PubMed2000

The vibratory properties of an obturator prosthesis with a soft lining material.

This study used modal analysis to evaluate the vibratory properties of cast obturator prostheses fitted with soft lining material. Three types of buccal flange bulbs were prepared: a resin (R) type; a 2 mm-thickness relined (RM) type; and a type fully relined with MOLTENO, (M) type. A vibration generator excited the obturator, while a Laser-Doppler Vibrometer detected the vibrations at specified measurement points. Both the excitation and response signals were sent to an FFT analyzer, which calculated the frequency response functions. Then, using DAMPCAL simulation software, the decay rates and the maximum amplitudes of rest and clasp parts were calculated. Statistical analysis was performed by means of one-way ANOVA with Fisher's PLSD test. The results indicated that for impacts simulated on both the defective and non-defective sides, the R type showed a significantly higher decay rate than did the other samples (p<0.0001). When impacts were directed at the non-defective side, the R and M types showed significantly smaller maximum amplitude values than did the RM type (p<0.0001). Only the M type, however, showed significantly smaller values when impacts were directed at the defective side (p<0.0001).

Analysis of Variance↗

PubMed1999

Proportion of reflux esophagitis in 6010 Japanese adults: prospective evaluation by endoscopy.

Compared with findings in Western countries, the prevalence of reflux esophagitis in Oriental countries is estimated to be low. In this prospective study, we aimed to examine the proportion of reflux esophagitis in Japanese adults, as evaluated by endoscopy. Endoscopists were prospectively directed to grade esophageal mucosal breaks with esophagitis according to the Los Angeles Classification of Esophagitis in all subjects that underwent endoscopic examination. In total, 6010 subjects underwent endoscopic examination for evaluation of esophagitis grading from December 1996 to February 1998. The subjects included 4394 outpatients who were not receiving medication for gastrointestinal disease and 1616 subjects who visited the hospital for routine physical examinations. The overall proportion of esophagitis was 16.3%. Most of the subjects with esophagitis were classified as having grade A or B (proportion of grades A and B, 9.6% and 4.6%, respectively). The age-related proportion of esophagitis and of severe esophagitis (i.e., grades C and D) increased in females aged over 70 and in males aged over 80. Increased body mass index (partly due to decreased height caused by osteoporosis), and/or hiatal herniation, were related to the proportion of esophagitis in females aged over 70. These data indicated that reflux esophagitis is a common disease in Japan. However, severe esophagitis (grades C and D) is not common.

Adult↗

PubMed1999

Anabolic effect of aminoterminally truncated fibroblast growth factor 4 (FGF4) on bone.

Fibroblast growth factor 4 (FGF4), a member of the FGF family, plays several important roles in bone development during embryogenesis. Systemic administration of FGF4 increases bone mass in rats, which suggests the potential therapeutic usefulness of this growth factor in treatment for osteopenia and in bone regeneration. We investigated the length of FGF4 required to exert its anabolic effects, because this information may be useful in developing new molecules to mimic the effects of FGF4. Because the active site of FGF family molecules is in the carboxylterminal region, we produced aminoterminally truncated recombinant human FGF4s (rhFGF4s) of different sizes. Human FGF4 cDNA containing almost the full length of the coding region (573 bp, 191 amino acid residues) was inserted into pUC18 vector and then deleted from the 5' end using the ExoIII system. Each of the deleted FGF4 cDNAs was subcloned into a pET29(+) expression vector. Differently sized recombinant proteins were expressed in the BL21(DE3)pLysS Escherichia coli strain and then purified. The growth-stimulative effects on NIH3T3 cells of each recombinant protein were examined by means of MTT colorimetric assay. Full-length and the shortened recombinant proteins, which stimulated NIH3T3 cell growth, were then subcutaneously administered into male ddY mice (6 weeks old) every day for 2 weeks. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computed tomography (pQCT). The rhFGF4 of 134 amino acid residues, the region homologous to other members of the FGF family, exerted a growth-stimulative effect on NIH3T3 cells comparable to the full-length version of FGF4; however, the shortest version, with 111 amino acid residues, showed a limited growth-stimulative effect. Systemic administration of the rhFGF4 of 134 amino acid residues increased the bone mineral density (BMD) of femurs at a dose of 0.1 mg/kg, which was comparable to that of the full-length rhFGF4. DEXA analysis, pQCT analysis, soft X-ray photos, and contact microradiographs revealed an increase in femoral trabecular bone in FGF4-treated animals; an increase in bone formation was also evident upon histomorphometric analysis. These results indicate that the region of FGF4 that is homologous to other FGF family members provides a sufficient anabolic effect in bone and that this recombinant protein is potentially useful as a therapeutic agent in bone.

3T3 Cells↗

PubMed1999

Influence of highly curved DNA segments on in vivo topology of plasmids.

Recombinant plasmids carrying a highly curved DNA structure are sometimes unstable in Escherichia coli. In order to know the underlying mechanism, several plasmids carrying one or two highly bent DNA segment(s) from the human adenovirus type 2 (Ad2) enhancer and/or origin region of phage lambda replication were systematically constructed and propagated in E. coli. The highly bent DNA segments disturbed the action of DNA topoisomerases: i.e. they were shown to be able to produce an anomalously wide spectrum of linking number topoisomers that tails toward lower supercoiling with a little of the DNA actually positively supercoiled. Furthermore, bent DNA caused multimeric plasmid formation. The linking number topoisomers and multimers seemed to be intermediate topological states of the bent DNA-containing plasmids that would lead to the deletion occurring in them. The nucleotide sequence of a deletion product of a bent DNA-containing plasmid showed that the putative source of the severe topological constraint was entirely eliminated from the plasmid.

Adenoviruses, Human↗

PubMed1999

Molecular composition of progenitor toxin produced by Clostridium botulinum type C strain 6813.

The molecular composition of the purified progenitor toxin produced by a Clostridium botulinum type C strain 6813 (C-6813) was analyzed. The strain produced two types of progenitor toxins (M and L). Purified L toxin is formed by conjugation of the M toxin (composed of a neurotoxin and a non-toxic nonhemagglutinin) with additional hemagglutinin (HA) components. The dual cleavage sites at loop region of the dichain structure neurotoxin were identified between Arg444-Ser445 and Lys449-Thr450 by the analyses of C-terminal of the light chain and N-terminal of the heavy chain. Analysis of partial amino acid sequences of fragments generated by limited proteolysis of the neurotoxin has shown to that the neurotoxin protein produced by C-6813 was a hybrid molecule composed of type C and D neurotoxins as previously reported. HA components consist of a mixture of several subcomponents with molecular weights of 70-, 55-, 33-, 26 through 21- and 17-kDa. The N-terminal amino acid sequences of 70-, 55-, and 26 through 21-kDa proteins indicated that the 70-kDa protein was intact HA-70 gene product, and other 55- and 26 through 21-kDa proteins were derived from the 70-kDa protein by modification with proteolysis after translation of HA-70 gene. Furthermore, several amino acid differences were exhibited in the amino acid sequence as compared with the deduced sequence from the nucleotide sequence of the HA-70 gene which was common among type C (strains C-St and C-468) and D progenitor toxins (strains D-CB16 and D-1873).

Amino Acid Sequence↗

PubMed1999

Dichain structure of botulinum neurotoxin: identification of cleavage sites in types C, D, and F neurotoxin molecules.

Botulinum neurotoxin (NT) is synthesized by Clostridium botulinum as about a 150-kDa single-chain polypeptide. Posttranslational modification by bacterial or exogenous proteases yielded dichain structure which formed a disulfide loop connecting a 50-kDa light chain (Lc) and 100-kDa heavy chain (Hc). We determined amino acid sequences around cleavage sites in the loop region of botulinum NTs produced by type C strain Stockholm, type D strain CB16, and type F strain Oslo by analysis of the C-terminal sequence of Lc and the N-terminal sequence of Hc. Cleavage was found at one or two sites at Arg444/Ser445 and Lys449/Thr450 for type C, and Lys442/Asn443 and Arg445/Asp446 for type D, respectively. In culture fluid of mildly proteolytic strains of type C and D, therefore, NT exists as a mixture of at least three forms of nicked dichain molecules. The NT of type F proteolytic strain Oslo showed the Arg435 as a C-terminal residue of Lc and Ala440 as an N-terminal residue of Hc, indicating that the bacterial protease cuts twice (Arg435/Lys436 and Lys439/Ala440), with excision of four amino acid residues. The location of cleavage and number of amino acid residue excisions in the loop region could be explained by the degree of exposure of amino acid residues on the surface of the molecule, which was predicted as surface probability from the amino acid sequence. In addition, the observed correlation may also be adapted to the cleavage sites of the other botulinum toxin types, A, B, E, and G.

Amino Acid Sequence↗

PubMed1999

The mature size of rat 4-aminobutyrate aminotransferase is different in liver and brain.

The amino acid sequence predicted from a rat liver cDNA library indicated that the precursor of beta-AlaAT I (4-aminobutyrate aminotransferase, beta-alanine-oxoglutarate aminotransferase) consists of a mature enzyme of 466 amino acid residues and a 34-amino acid terminal segment, with amino acids attributed to the leader peptide. However, the mass of beta-AlaAT I from rat brain was larger than that from rat liver and kidney, as assessed by Western-blot analysis, mass spectroscopy and N-terminal sequencing. The mature form of beta-AlaAT I from the brain had an ISQAAAK- peptide on the N-terminus of the liver mature beta-AlaAT I. Brain beta-AlaAT I was cleaved to liver beta-AlaAT I when incubated with fresh mitochondrial extract from rat liver. These results imply that mature rat liver beta-AlaAT I is proteolytically cleaved in two steps. The first cleavage of the motif XRX( downward arrow)XS is performed by a mitochondrial processing peptidase, yielding an intermediate-sized protein which is the mature brain beta-AlaAT I. The second cleavage, which generates the mature liver beta-AlaAT I, is also carried out by a mitochondrial endopeptidase. The second peptidase is active in liver but lacking in brain.

4-Aminobutyrate Transaminase↗

PubMed1999

Detection and nucleotide sequence analysis of human caliciviruses (HuCVs) from samples in non-bacterial gastroenteritis outbreaks in Hokkaido, Japan.

Samples of feces and vomit collected from patients during 13 non-bacterial gastroenteritis outbreaks which occurred in Hokkaido between 1995 and 1998 were examined by electron microscopy (EM) and reverse-transcription polymerase chain reaction (RT-PCR) for evidence of infection with human caliciviruses (HuCVs). In 6 food-borne outbreaks, oysters were the probable source of infection, while the origin of HuCVs was not found out for the other 7 outbreaks. One-hundred-eleven of 214 stool, vomit and oyster specimens examined gave positive results by RT-PCR, while HuCVs were detected by EM in 36 of 121 stool specimens examined. We determined the nucleotide sequences of 470-bp or 373-bp PCR products amplified from the RNA polymerase region of the HuCV genomes with primer sets MR3/4 and Yuri22F/R, respectively. The sequences of different strains revealed great heterogenicity, with a range of 60 to 100% homology among strains. In a few cases, a mixed genotype was found in the same patient or same outbreak by means of nested PCR and cloning of PCR products into an appropriate vector. Of the 19 different strains found, 4 strains could be classified as Norwalk virus (genogroup 1) and the other 15 strains as Snow Mountain agent (genogroup 2) based on genotyping with homology analysis. Furthermore, the strains belonging to genogroup 2 could be classified into 4 subgroups with more than 93% homology in amino acids among strains in the subgroup.

Animals↗

PubMed1999

A dual topoisomerase inhibitor, TAS-103, induces apoptosis in human cancer cells.

TAS-103 (6-[[2-(dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c] quinolin-7-one dihydrochloride), a dual topoisomerase (topo) inhibitor, was developed as an anticancer agent by targeting topo I and topo II and has previously been shown to be effective against lung tumors. In this study, we investigated the cytotoxic activity of TAS-103 in various human cancer cell lines (including gastric, colon, squamous, lung, and breast cancer cells) and the induction of apoptosis by TAS-103. We next established stable transfectants of Bcl-2 in the gastric cancer cell line AZ521 and found that Bcl-2 blocked TAS-103-induced apoptosis. In addition, we demonstrated that the activities of ICE-like and CPP32-like proteases are involved in the signal transduction pathway of TAS-103-induced apoptosis. In summary, TAS-103 is a novel type of anticancer agent with a unique mechanism and could be useful as a lead compound for development of new drugs.

Aminoquinolines↗

PubMed1999

Direct and rapid detection by PCR of Erysipelothrix sp. DNAs prepared from bacterial strains and animal tissues.

A PCR method for rapid screening of Erysipelothrix spp. in the slaughterhouse was carried out by using four species-specific sets of oligonucleotide primers after initial amplification with the primer set MO101-MO102, which amplifies the 16S rRNA sequences of all four Erysipelothrix species. The DNA sequences coding for the rRNA gene cluster, including 16S rRNA, 23S rRNA, and the noncoding region downstream of 5S rRNA, were determined in order to design primers for the species-specific PCR detection system. The homology among the 4.5-kb DNA sequences of the rRNA genes of Erysipelothrix rhusiopathiae serovar 2 (DNA Data Bank of Japan accession no. AB019247), E. tonsillarum serovar 7 (accession no. AB019248), E. rhusiopathiae serovar 13 (accession no. AB019249), and E. rhusiopathiae serovar 18 (accession no. AB019250) ranged from 96.0 to 98.4%. The PCR amplifications were specific and were able to distinguish the DNAs from each of the four Erysipelothrix species. The results of PCR tests performed directly with tissue specimens from diseased animals were compared with the results of cultivation tests, and the PCR tests were completed within 5 h. The test with this species-specific system based on PCR amplification with the DNA sequences coding for the rRNA gene cluster was an accurate, easy-to-read screening method for rapid diagnosis of Erysipelothrix sp. infection in the slaughterhouse.

Abattoirs↗

PubMed1999

Study of mandibular movements in mandibulectomy patients--border movements and functional movements during mastication, deglutition and speech.

In mandibulectomy patients who have not undergone surgical reconstruction, the remaining mandibular segment is unstable and often deviated. Its movements have low reproducibility during mastication, deglutition and speech. The purpose of this study was to clarify three-dimensionally the differences in mandibular movements for each of these oral functions in mandibulectomy patients with and without mandibular continuity. Four mandibulectomy subjects (Group I) without mandibular continuity and three subjects (Group II) with mandibular continuity were selected. Their mandibular movements were recorded using a jaw movement tracking device with six degrees of freedom. Each movement was assessed graphically at the virtual incisor point and the rotational angles of the mandible in the frontal, sagittal and horizontal plane were analyzed. The findings were as follows; 1. In Group I, the border movements at the virtual incisor point exhibited an irregular and asymmetric envelope deviated to the resected side in the frontal plane, whereas Group II exhibited a smooth and symmetric envelope. 2. In Group I, the rotational angles in the frontal plane during border movements and mastication, in all planes during speech, and in the frontal and horizontal plane during deglutition were significantly larger than in Group II. A comparison among border and all functional movements in mandibulectomy patients revealed characteristic movements in the rotation of the mandible in the frontal plane. It is suggested that the rotational angle of the mandible is a useful parameter for assessment of mandibular movements in mandibulectomy patients.

Aged↗

PubMed1999

Evaluation of obturator prostheses using vibration analysis.

Obturator prostheses have been extensively used in the functional rehabilitation of maxillectomy patients. The purpose of this study was to evaluate in vitro the vibration movements of three types of obturator prostheses. Three types of bulbs were used: the solid type, the buccal flange type, and the hollow type. Modal analysis was performed to identify the better form. The three types of obturator prostheses were excited by a shaker, and the frequency response functions were recorded on an FFT analyzer to identify their modal shapes. In addition, transient response simulations were carried out, and decay rates of the resultant transient response waves were compared to evaluate the energy absorption after the obturator prosthesis had experienced an impact. The results showed that the modal shapes were closely similar, while the amplitudes at the rests and clasps of the hollow type bulb were the smallest. In the transient response simulation, the decay rates of the hollow type were significantly the highest (p < 0.01). In this study, modal analysis demonstrated that the hollow type obturator prosthesis showed the steepest vibration decay slope, indicating that it might be the best among the three types of bulbs for use in clinical treatments.

Analysis of Variance↗

PubMed1999

Eight-year trend of new patients at Clinic for Disabled Patients, University Hospital, Faculty of Dentistry, Tokyo Medical and Dental University.

The trend of new patients was investigated at the Clinic for Disabled Patients, University Hospital, Faculty of Dentistry, Tokyo Medical and Dental University for eight years from 1989 to 1996. The purpose of this study was to explore the future role of this specialized clinic. The study revealed the following information: 1. A total of 1,388 new patients, corresponding to 173.5 new patients per year on average, visited the clinic. 2. The percentage of patients aged 30 or more increased. As a result, the mean patient age rose from 40.4 in 1989 to 47.6 in 1996. 3. Referrals accounted for more than 80% of new patients. Medical doctors referred more patients to our clinic than dentists did. 4. While the percentage of disabled patients tended to decrease, the percentage of medically compromised patients increased. 5. The predominant complaint was dental caries. Patients with cardiovascular diseases also complained of gingival bleeding and ill-fitting dentures. The growing percentage of medically compromised patients and the increasing mean age of patients over the eight-year period seems to reflect advances in medical science and the aging society. These tendencies could be more remarkable in the future. Therefore, much closer cooperation between dentists and medical doctors will be required.

Adolescent↗