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Biomedical subjects

T Yamashiro

Publications and source records attributed to T Yamashiro.

At least 55 records · Page 3Linked to original sources

Behçet's colitis.

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Anti-Inflammatory Agents, Non-Steroidal↗

A filamentous phage of Vibrio parahaemolyticus O3:K6 isolated in Laos.

A filamentous phage, 'lvpf5,' of Vibrio parahaemolyticus O3:K6 strain LVP5 was isolated and characterized. The host range was not restricted to serotype O3:K6, but 7 of 99 V. parahaemolyticus strains with a variety of serotypes were susceptible to the phage. The phage was inactivated by heating at 80 C for 10 min and by treating with chloroform. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the phage exhibited a 3.8 kDa protein. The amino-terminal amino acid sequence of the coat protein was determined as AEGGAADPFEAIDLLGVATL. The phage genome consisted of a single-stranded DNA molecule. The activity of the phages was inhibited by anti-Na2 pili antibody.

Amino Acid Sequence↗

Functional recovery after coronary artery bypass grafting in patients with severe left ventricular dysfunction and preserved myocardial viability in the left anterior descending arterial territory as assessed by thallium-201 myocardial perfusion imaging.

To evaluate the functional recovery after coronary bypass surgery in patients with severe left ventricular (LV) dysfunction (ejection fraction (EF) < or = 35%), 100 consecutive patients with viable myocardium in the territory supplied by the left anterior descending artery (LAD) underwent coronary bypass grafting. In addition, cardiac catheterization and single-photon emission computed tomography (SPECT) perfusion imaging with thallium-201 were repeated 1-year postoperatively. Although 12 patients with severe LV dysfunction were preoperatively in a worse New York Heart Association functional class (3.1+/-0.7 vs 2.4+/-0.8; p<0.01), had a higher incidence of heart failure (10/12 vs 14/88; p<0.001) and had a worse LVEF (29+/-5 vs 61+/-14%; p<0.001) compared with 88 patients without severe LV dysfunction, the operative mortality was similar in the 2 groups (1/12 vs 2/88; p=NS). The postoperative NYHA functional class in the patients with severe LV dysfunction was similar to that in the patients without such dysfunction (1.6+/-0.7 vs 1.3+/-0.6; p=NS). In addition, the 1-year postoperative study revealed a significant improvement in the thallium defect score in both the LAD territory (1.7+/-1.2 to 0.7+/-1.0, p=0.01) and all the territories (5.2+/-2.2 to 3.2+/-1.9, p=0.002) in patients with severe LV dysfunction, whereas no improvement in defect score was found in either of these territories in those without severe LV dysfunction (LAD: 0.6+/-1.4 to 0.4+/-1.2, p=NS; All: 1.9+/-2.2 to 1.8+/-2.0, p=NS). Furthermore, a marked 1-year postoperative improvement (15-24%; 95% confidence interval) in LVEF (29+/-5 to 48+/-10%, p<0.001) was demonstrated in patients with severe LV dysfunction, but not in those without such dysfunction (60+/-13 to 61+/-11%, p=NS). These results indicate that myocardial viability in the LAD territory, as demonstrated by thallium-201 SPECT perfusion imaging, predicts a significant improvement in functional class and LVEF of at least 10% or more after coronary artery bypass grafting in patients with severe LV dysfunction.

Adult↗

Double lung cancer combined with idiopathic thrombocytopenic purpura. A case report.

A 68-year-old woman was admitted because of two abnormal lung shadows, which later proved to be differentiated double cancer. Preoperative hematology tests showed a low platelet count and the result of bone marrow aspiration was compatible with idiopathic thrombocytopenic purpura (ITP). A normal platelet count was once obtained by preoperative percutaneous partial splenic arterial embolization (PSE). However, as there was a tendency for the platelet count to decrease just before surgery, one shot high-dose immunoglobulin (Ig) was administered, which is thought to have a short term effect. The operation was performed successfully. After resection of lung cancer, her platelet count was maintained at around 15x10(4) mm3 without taking drugs for ITP. These findings suggest a relationship between lung cancer and ITP.

Adenocarcinoma↗

Requirement of expression of P-glycoprotein on human natural killer leukemia cells for cell-mediated cytotoxicity.

The requirement of P-glycoprotein, a product of the multidrug resistance (MDR)1 gene, for natural killer (NK) cell-mediated cytotoxicity was examined by using a human NK-like cell line, YTN, which is cytotoxic toward JY cells. YTN cells express P-glycoprotein, a judged by flow cytometry and polymerase chain reaction of reverse-transcribed mRNA. YTN cell-mediated cytotoxicity was inhibited by MDR-reversing reagents as well as the F(ab')2 fragment of a monoclonal antibody against P-glycoprotein. Furthermore, antisense oligonucleotides for MDR1 mRNA inhibited expression of P-glycoprotein as well as YTN cell-mediated cytotoxicity. Thus, this study provides firm evidence that P-glycoprotein plays an essential role in cell-mediated cytotoxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Assessment of internal thoracic artery graft with intraoperative color Doppler ultrasonography.

BACKGROUND: Intraoperative ultrasonography has the potential to provide anatomic and functional information about internal thoracic artery (ITA) graft, but this potential has been hindered by the relatively large standard probe. In this study, we used a color Doppler microprobe to evaluate ITA grafts. METHODS: The subjects were 15 consecutive patients who underwent elective coronary artery bypass grafting either with cardiopulmonary bypass (n = 14) or without (n = 1). All patients underwent anastomosis of the left ITA to the left anterior descending artery. The ITA graft was assessed before the chest was closed, with the microprobe placed directly on the graft. RESULTS: A good-quality color Doppler image of the ITA graft was easily obtained in all 15 patients within a few minutes. The ITA graft function was assessed by analyzing the shape of the pulsed Doppler wave. All ITA grafts were patent, and the mean graft diameter was 1.8 +/- 0.04 mm. The peak systolic velocity, peak diastolic velocity, and mean velocity were 52.0 +/- 14.9 cm/s, 58.3 +/- 22.4 cm/s, and 36.5 +/- 10.9 cm/s, respectively. The ratio of peak diastolic velocity to peak systolic velocity was 1.24 +/- 0.66. The ITA graft seemed to function well when the biphasic diastolic predominant flow appeared. The mean blood flow was 55.1 +/- 22.0 mL/min. CONCLUSIONS: Intraoperative ultrasonography using the microprobe provides adequate anatomic and hemodynamic information regarding ITA grafts. As the Doppler flow evaluation has high sensitivity and specificity, we suggest that intraoperative ultrasonography is useful for the assessment of these grafts.

Anastomosis, Surgical↗

Differential responses of mandibular condyle and femur to oestrogen deficiency in young rats.

This response of condyle and femur was evaluated by histomorphometry. Five female Sprague-Dawley rats, 6 weeks of age, were subjected to bilateral ovariectomy, and five others were sham-operated. They were then killed 32 days later. Ovariectomy significantly increased the total thickness of the condylar cartilage and distal femoral growth-plate cartilage in the young, growing rats. Ovariectomy caused a 2-fold increase in thickness of the proliferative layer and a 4-fold increase in thickness of the hypertrophic layer in the condylar cartilage, and a 1.3-fold increase in thickness of the proliferative layer in the epiphyseal growth cartilage of the femur. Ovariectomy had no effect on the percentage of trabecular bone volume, the percentage of the bone surface covered by osteoblasts (Ob.S/BS) and osteoclasts (Oc.S/BS), and number of osteoclasts per bone surface (N.Oc/BS) in the mandibular condyle. On the contrary, ovariectomy caused a 68.5% decrease in bone volume, a 4-fold increase in Ob.S/BS, and 2-fold increases in Oc.S/BS and N.Oc/BS in the secondary spongiosa of the rat distal femur. Thus there was a prominent difference in the response to oestrogen deficiency between the mandibular condyle and femur in young growing rats.

Animals↗

Case report: facial asymmetry and early condylar fracture.

This report describes the surgical-orthodontic treatment of two adult females who exhibited dentofacial asymmetry. Their medical histories included early condylar fractures. Growth was disturbed on the fractured side, resulting in mandibular deviation and maxillary canting. Following the completion of growth, the asymmetries were corrected by combined orthodontic-surgical treatment. The treatment planning procedures and the results are presented.

Adult↗

Case report: orthodontic treatment of dental problems in incontinentia pigmenti.

Incontinentia pigmenti is an uncommon genodermatosis that occurs in female infants. The characteristic dental defects are partial anodontia and the presence of some peg-shaped teeth. This report describes a patient with incontinentia pigmenti who exhibited multiple missing teeth in both arches. The patient had malpositioned teeth and decreased occlusal vertical dimension associated with the missing teeth. Orthodontic treatment was required for prosthetic purposes. The dental anomalies of incontinentia pigmenti and the treatment procedure are presented.

Adult↗

Pure red cell aplasia and myasthenia gravis with thymoma: a case report and review of the literature.

A case of pure red cell aplasia (PRCA), myasthenia gravis (MG) and thymoma is reported. A 70-year-old woman presented with severe anemia. She had been diagnosed as having MG 8 years earlier and her symptoms were adequately controlled with ambenonium chloride. When she visited our hospital, her hematocrit was 13.7% with a hemoglobin concentration of 4.7 g/dl and her reticulocyte counts were persistently abnormal at 0.1%. Although both direct and indirect Coombs' tests were positive, there was no evidence of hemolysis. Routine screening tests for other etiologies of anemia were negative. Serological tests for anti-DNA and anti-acetylcholine receptor antibodies gave positive results. A bone marrow examination revealed severe erythroid hypoplasia. PRCA was diagnosed and the patient was treated with periodic transfusions. A lateral view chest roentgenogram and a computed tomography scan of the thorax showed the presence of an anterior mediastinal mass which was suspected to be thymoma. The patient underwent thymothymectomy and the tumor was diagnosed as a thymoma. Although the patient received no treatment for MG and PRCA after surgery, her hematological test results rapidly improved and she was discharged from the hospital on the 29th postoperative day. At that time, her hematocrit was 33.2%, her hemoglobin concentration was 10.0 g/dl, her peripheral reticulocyte level was 1.8% and her left partial ptosis had improved. She is doing well, 9 months after surgery. For a patient to remain in remission without treatment for PRCA and MG after thymothymectomy is extremely rare.

Aged↗

Adhesive property of toxin-coregulated pilus of Vibrio cholerae O1.

The adhesive property of toxin-coregulated pilus (TCP) to the human intestine jejunum), and whether or not TCP mediates the adhesion of Vibrio cholerae 395 organisms to the intestinal epithelium were investigated using visually proving methods. The purified TCP did not agglutinate human erythrocytes nor adhere to the surface of human intestinal epithelium. V. cholerae 395 adhered to the epithelium, but the adhesion was not inhibited by blocking the pili with the Fab fraction of anti-TCP IgG. The organisms adhered to the intestine treated with purified TCP in advance, as well as to the intact intestine. These findings suggest that TCP is not involved in the adhesion of these organisms to the intestinal epithelium.

Adhesins, Bacterial↗

Filamentous phage fs1 of Vibrio cholerae O139.

Filamentous phage, fs1, was obtained from Vibrio cholerae O139. The lysogenized strains produced a large amount of fs1 phage in the culture supernatant. This phage was previously reported as novel fimbriae of that organism. The genome of the phage was a 6.5 kb single-stranded DNA. The capsid of fsl consists of a small molecule peptide (about 2.5 kDa).

Capsid↗

Etiological study of diarrheal patients in Vientiane, Lao People's Democratic Republic.

The etiological agents of diarrhea in Vientiane, Lao People's Democratic Republic (Lao PDR), were studied in the period from October 1996 to August 1997. A total of 880 patients with diarrhea visiting medical facilities were examined for Shigella, Salmonella, diarrheagenic Escherichia coli, vibrio, Aeromonas, Campylobacter, and rotavirus. Shigella spp., heat-stable enterotoxin (ST)-producing E. coli, and serogroup-based enteropathogenic E. coli were found to be the main organisms causing diarrhea in Vientiane, with frequencies of 16.8% (148 of 880), 17.2% (111 of 645), and 11.0% (97 of 880), respectively. Relatively low incidences were observed in the cases of Salmonella spp., (0.6%; 5 of 880), Campylobacter spp. (4.4%; 39 of 880), and rotavirus (6.1%; 9 of 148), and no isolates of V. cholerae O1 or O139 or Aeromonas were recovered. An analysis of the incidences of enteropathogens with respect to age and seasonal variations demonstrated that the frequencies of isolation of Shigella spp. and heat-labile enterotoxin-producing E. coli were significantly higher in those aged 1 to 5 years than in those younger than 1 year of age and those older than 5 years of age (P < 0.0001 and P < 0.05, respectively) and that the frequencies of isolation of Shigella spp. and ST-producing E. coli were significantly higher in the rainy season than in the dry season (P < 0.005 and P < 0.001, respectively). Almost all strains of Shigella spp. tested were resistant to ampicillin, tetracycline, and erythromycin and were susceptible to cefdinir and ofloxacin. This is the first intensive and longitudinal study to define the etiologic agents of diarrheal diseases in Lao PDR.

Adolescent↗

Expression of Fos in the rat forebrain following experimental tooth movement.

Orthodontic tooth movement is known to cause pain and discomfort to patients. Mechanically induced inflammatory responses in the periodontium are assumed to be related to the mechanism of pain sensation. An immediate-early gene, c-fos, that is expressed within some neurons following synaptic activation, is widely used as a marker for neuronal activity following noxious or innocuous stimulation. We have recently demonstrated that experimental tooth movement produced Fos induction in the ipsilateral trigeminal subnucleus caudalis and in the bilateral lateral parabrachial nucleus, which is known to be involved in the transmission of nociceptive information. As a further step, we investigated the distribution of Fos-like immunoreactive neurons in the upper brain regions. Twenty-four hours after the commencement of the experimental tooth movement, the Fos-like immunoreactive neurons appeared in the central nucleus of the amygdala (Ce), paraventricular nucleus of the hypothalamus (PVH), and paraventricular nucleus of the thalamus (PV) of the experimental rats. The numbers of the labeled neurons were significantly increased by 639% (P < 0.001) and 644% (P < 0.001) in the ipsilateral and contralateral sides of the Ce, respectively, by 292% (P < 0.001) and 307% (P < 0.001) in the ipsilateral and contralateral sides of the PVH, and by 264% (P < 0.0001) in the PV with respect to sham control rats. These results suggest that nociceptive information caused by experimental tooth movement might be transmitted and modulated in several regions of the forebrain.

Analysis of Variance↗

c-fos expression in the trigeminal sensory complex and pontine parabrachial areas following experimental tooth movement.

Ortodontic tooth movement causes continuous pain. However, it does not appear immediately, usually appearing after the application of orthodontic force to the teeth. Mechanically induced inflammatory responses in the periodontal membrane are assumed to be related to the mechanism of the later pain sensation. In the present study, we investigated Fos-like immunoreactivity in the trigeminal sensory complex and pontine parabrachial areas 24 h after the commencement of experimental tooth movement. An orthodontic elastic module was unilaterally inserted between upper molars. Following experimental tooth movement, Fos-like immunoreactive neurons appeared ipsilaterally in the trigeminal subnucleus caudalis and bilaterally in the lateral parabrachial nucleus. These results indicate that experimental tooth movement evokes delayed and continuous nociception after application of orthodontic force to the teeth and that the nociceptive information would be conveyed to the ipsilateral trigeminal subnucleus caudalis and further processed, at least in part, to the lateral parabrachial nucleus.

Animals↗

Reduction of intracellular pH by inhibitors of natural killer cell activity, nicardipine, methyl 2-(N-benzyl-N-methylamino)ethyl-2,6-dimethyl-4-(2-isopropyl-pyrazolo[1, 5-a]pyridine-3-yl)-1,4-dihydro-pyridine-3,5-dicarboxylate (AHC-52), and 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS).

Our previous study showed that nicardipine and its structural analog, methyl 2-(N-benzyl-N-methylamino)ethyl-2,6-dimethyl-4-(2-isopropyl-pyrazolo[1,5 -a]pyridine-3-yl)-1,4-dihydro-pyridine-3,5-dicarboxylate (AHC-52), which is devoid of calcium channel blocking activity, were equally effective in inhibiting natural killer (NK) cell activity, perhaps through inhibition of P-glycoprotein. In this study, we confirmed this finding using a human NK-like cell line, YTN, which is highly cytotoxic to JY cells. The YTN cell-mediated cytotoxicity toward JY cells was inhibited by nicardipine and AHC-52 in a concentration-dependent manner, the concentrations required for 50% inhibition being 14 and 7 microM, respectively. We then examined by flow cytometry whether these reagents modulate the intracellular pH (pHi), since P-glycoprotein reportedly plays a role in pHi homeostasis, perhaps by altering chloride translocation. Both reagents reduced pHi at concentrations similar to those required for inhibition of the cytotoxicity. In addition, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS), an inhibitor of anion exchangers, also inhibited NK cell activity, with an IC50 value of 160 microM, and reduced pHi at a similar concentration, although it is not a P-glycoprotein blocker. Thus, the inhibitory activities of nicardipine, AHC-52, and DIDS toward NK cell activity paralleled their lowering activities of pHi, suggesting the possibility that disregulation of pHi is related to inhibition of NK cell activity.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

CMO I deficiency caused by a point mutation in exon 8 of the human CYP11B2 gene encoding steroid 18-hydroxylase (P450C18).

Corticosterone methyloxidase I (CMO I) deficiency is an autosomal recessive disorder of aldosterone biosynthesis. To determine further the molecular genetic basis of CMO I deficiency, a patient of Turkish origin that suffered from CMO I deficiency was studied. Nucleotide sequencing of the PCR-amplified exons from the genomic DNA of this patient revealed a single point mutation CTG (leucine) CCG (proline) at codon 461 in exon 8 of CYP11B2, which is involved in the putative heme binding site of steroid 18-hydroxylase (P450(C18)). The expression study using a cDNA introducing the point mutation revealed that the amino acid substitution totally abolishes the P450(C18)p3 enzyme activities required for conversion of 11-deoxycorticosterone to aldosterone, even though the mutant product was detected in the mitochondrial fraction of the transfected cells. These results suggest that this point mutation causes CMO I deficiency.

Aldosterone↗

Target cell-induced calcium signals in human natural killer leukemia cells as revealed by confocal fluorescence microscopy.

The target cell-induced calcium response in natural killer (NK) cells was examined using indo-1 (a ratiometric fluorochrome), a newly developed video-rate ultraviolet laser-scanning confocal microscope system, and a human NK leukemia cell line, YTN. Susceptible target cells (JY cells), but not unsusceptible target cells (K562 cells), increased the intracellular calcium concentration ([Ca]i) in almost all indo-1-loaded YTN cells with a lag time, although the kinetics of increase in [Ca]i differed in individual YTN cells. The increase in [Ca]i was completely blocked by 2 mM EGTA and partially (around 50%) blocked by 10 microM nicardipine, the extents of inhibition of calcium response correlating well with those of inhibition of cytotoxic activity. Thus, the calcium response in YTN cells observed in this study may constitute a critical step in the manifestation of cytotoxic activity.

Biological Transport↗