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Biomedical subjects

K Tabuchi

Publications and source records attributed to K Tabuchi.

At least 55 records · Page 3Linked to original sources
PubMed2000

[A case report of a successful surgical treatment for infective endocarditis involving four valves in a elderly patient with ventricular septal defects].

A 72-year-old female was examined because of acute congestive heart failure. Echocardiogram revealed vegetations on aortic and pulmonary valve, regurgitation of four valves, and perimembraneous ventricular septal defect. Aortic valve replacement, mitral valve replacement, repair of tricuspid valve using a Carpentier ring, partial resection of pulmonary valve, and direct closure of VSD was performed. Pathological finding of resected valves showed acute endocarditis. A patient resumed social activities after surgery.

Aged↗
PubMed1999

Peroxiredoxin I expression in human thyroid tumors.

Peroxiredoxin I (Prx I) is newly discovered oxidative stress inducible protein, having a thioredoxin peroxidase activity. The Prx I expression level in 107 samples out of 60 thyroid lesions, including normal thyroid, tumors and thyroiditis including Graves' disease were examined using immunoblotting. Prx I expression levels in follicular neoplasm (P = 0.00005) and thyroiditis group (P = 0.0037) were significantly higher than that of the control group, while papillary carcinoma group did not show statistical significance. Immunohistochemistry indicated that Prx I was in epithelial cells of thyroid follicles. These results suggest that Prx I is expected to be a candidate for novel tumor markers to discriminate tissue types of tumors.

Adult↗
PubMed1999

Heme oxygenase-1 expression in oral squamous cell carcinoma as involved in lymph node metastasis.

Thirty-eight oral squamous cell carcinomas (SCCs) were semi-quantitatively analyzed by immunohistochemical staining, and the relation between heme oxygenase-1 (HO-1) expression and the clinical status were correlated. High immunostaining of HO-1 was detected in lymph node metastasis negative groups (P = 0.0018) and in well-differentiated SCCs (P = 0.0016). There were no significant correlations between heme oxygenase-1 expression and other factors, such as size of the tumor, staging, age and sex. These findings further support the proposition that high heme oxygenase-1 expression in oral SCCs can be useful in identifying patients at low risk of lymph node metastasis.

Adult↗
PubMed1999

Thallium-201 SPECT of adjacent intracranial tumours: a contrast in thallium kinetics.

We report a case of adjacent intracranial tumours: malignant fibrous histiocytoma (MFH) and meningioma. Thallium-201 single-photon emission computed tomography demonstrated different thallium kinetics between the tumours (slow washout from the MFH and rapid clearance in the meningioma) and could be said to have been useful for preoperative histological estimation.

Aged↗
PubMed1999

Esophageal varices before and after endoscopic variceal ligation: evaluation using helical CT.

The purpose of this study was to demonstrate the utility of helical CT in assessing the therapeutic effects of endoscopic variceal ligation (EVL). Twenty-four patients with esophageal varices were examined. Helical scanning was initiated 60 s after intravenous injection (Iopamidol 300 mgI/ml, total 120 ml, 3 ml/s) was started. Esophageal varices were clearly depicted as high-density areas. Multiplanar reformation and 3D images demonstrated collateral circulation three-dimensionally. After EVL, mucosal high-density areas had diminished markedly, but collateral veins around the esophagus, and gastro- and/or spleno-renal shunts, were unchanged in all patients. Of 21 patients with collateral circulation, esophageal varices recurred endoscopically in 6 patients within 12 months. In 3 patients without collateral circulation, esophageal varices did not recur within 12 months. From these findings, we conclude that helical CT is a useful method for assessing the therapeutic effects of EVL.

Collateral Circulation↗
PubMed1999

Effect of A1 adenosine receptor agonist upon cochlear dysfunction induced by transient ischemia.

The present study was undertaken to determine whether 2-chloro-N6-cyclopentyladenosine (CCPA), a highly selective A1 adenosine receptor agonist, attenuated cochlear dysfunction induced by transient ischemia or not. Ischemia of different durations (15, 30 or 60 min) was induced in 46 albino guinea pigs by transiently pressing the labyrinthine artery. CCPA or physiological saline solution was intraperitoneally administered to the animals 15 min prior to ischemia. The post-ischemic CAP threshold shift from the pre-administration value was measured 4 h after the onset of reperfusion to assess post-ischemic cochlear dysfunction. A statistically significant reduction in the CAP threshold shift was seen in CCPA-given animals after 15- and 30-min ischemia, whereas there was no statistical difference after 60-min ischemia. These results suggest that A1 adenosine receptor agonist exerts a protective effect on the cochlear injury induced by transient ischemia of intermediate duration.

Action Potentials↗
PubMed1999

A genetic approach to visualization of multisynaptic neural pathways using plant lectin transgene.

The wiring patterns among various types of neurons via specific synaptic connections are the basis of functional logic employed by the brain for information processing. This study introduces a powerful method of analyzing the neuronal connectivity patterns by delivering a tracer selectively to specific types of neurons while simultaneously transsynaptically labeling their target neurons. We developed a novel genetic approach introducing cDNA for a plant lectin, wheat germ agglutinin (WGA), as a transgene under the control of specific promoter elements. Using this method, we demonstrate three examples of visualization of specific transsynaptic neural pathways: the mouse cerebellar efferent pathways, the mouse olfactory pathways, and the Drosophila visual pathways. This strategy should greatly facilitate studies on the anatomical and functional organization of the developing and mature nervous system.

Animals↗
PubMed1999

Effect of nitric oxide synthase inhibitor on cochlear dysfunction induced by transient local anoxia.

To evaluate whether nitric oxide (NO) plays a role in the mechanism of generation of cochlear dysfunction induced by anoxia and reperfusion, the effects of a nitric oxide synthase (NOS) inhibitor, N-nitro-L-arginine, were examined using 71 albino guinea pigs. Transient cochlear anoxia of different duration (15, 30 or 60 min) was induced by pressing the labyrinthine artery and compound action potential (CAP) was measured before and 4 h after anoxia. N-nitro-L-arginine (1-30 mg/kg) administered intraperitoneally 1 h before the onset of anoxia alleviated the cochlear dysfunction when the anoxic period was 15 or 30 min. No beneficial effect was observed, however, in the 60-min anoxia. These results indicate that NO contributes to the generation of anoxia-induced cochlear dysfunction and that NOS inhibitor has a protective effect on the cochlear injury induced by anoxia of moderate duration.

Action Potentials↗
PubMed1999

Methods for rapid cloning and detection for sequencing of cloned inverse PCR-generated DNA fragments adjacent to known sequences in bacterial chromosomes.

Since the invention of PCR, many adaptation techniques have been developed for sequencing DNA fragments flanking known sequences. Of them, inverse PCR is a matter of interest because of the simplicity of its principle. However, the protocols for inverse PCR introduced so far consist of some time-consuming procedures, and with them, we cannot "walk" chromosomes too far since the number of suitable restriction enzymes is limited. Our experiments led to confirming simpler technical approaches applicable to the case of bacterial chromosomes, that is, designing two end-specific "contextual" sequences with which we can quickly detect the desired clones of targeted DNA fragments by simply analyzing PCR products, employing "the minimum value of the desired fragments" as a "discriminating minimum" value to decrease contaminant DNA fragments, and creating a new tandem of two cleaved end fragments of a known sequence ("reordering") for PCR amplification in combination with cloning of the inverse PCR-generated DNA. With the improvements, we could both simplify the procedures and broaden the capacity of the inverse PCR in "walking" chromosomes.

Chromosomes, Bacterial↗
PubMed1999

[Study on the verotoxin-producing Escherichia coli--isolation of the bacteria from deer dung].

To identify the source and route of verotoxin-producing Escherichia coli (VTEC) infection in humans, we tried to isolate VTEC from fresh deer dung collected from free-range animals in two parks during the period from August 1997 to January 1998. The results are presented below. 1) VTEC were isolated from 21 of 200 deer dung samples (10.5%), consisting of 15 of 100 samples (15.0%) collected in park A and 6 of 100 samples (6.0%) collected in park B, suggesting that the incidence of VTEC isolation differs depending on location. 2) With respect to typing of verotoxin, the 21 isolated VTEC strains consisted of 10 strains (47.6%) as VT1 producer, 5 strains (23.8%) as VT2 producer, and 6 strains (28.6%) as double producer of both types. 3) With respect to serogroup of the isolated VTEC strains, 2 strains belonged to O128:H2.1 strain each belonged to the O8:H10, O128:H12, and O169:HUT groups. The remaining 16 strains failed to be identified as particular serotypes. Regarding local distribution of the serotype, in park A, 1 strain each belonged to the O128:H2, O8:H10, and O169:HUT groups. The remaining 12 strains did not clearly show particular serotypes. In park B, 2 strains belonged to O128:H2, and 4 strains failed to show particular serotypes. The remaining 1 strains showed autoagglutination. In conclusion, we isolated VTEC strains from deer that showed types of toxin and serogroups identical to those of human VTEC. Therefore, VTEC found in deer dung could well be a source of VTEC-infectious diseases in humans.

Animals↗
PubMed1999

[Prevalence and serotypes of verocytotoxin-producing Escherichia coli (VTEC) isolates from dairy cattle].

To clarify the source of infection and route of transmission of Verocytotoxin-producing Escherichia coli (VTEC) in humans, we collected fresh feces from healthy dairy cattle reared in Hokkaido, Fukushima, Kanagawa and Okinawa prefectures between June 1996 and March 1997, and attempted to isolate VTEC. The results are described below. 1) VTEC was isolated from 68 (27.1%) of 251 fecal samples tested. VTEC was isolated from 14 (28.0%) of 50 in Hokkaido, 13 (26.0%) of 50 in Fukushima, 20 (39.2%) of 51 in Kanagawa and 21 (21.0%) of 100 in Okinawa. There were no difference in the prevalence among the prefectures. 2) Toxin type and serotype of 85 isolates were determined. Thirty-three isolaties (38.8%) were classified into VT1 toxin and VT2 toxin, respectively, and 19 isolates (22.4%) were classified as the strain that produces both VT1 and VT2 toxins. The toxin types of these isolates were divided by serotypes. The VT1-producing isolates were the most frequent among O111:H-. The VT2-producing isolates included O2:H12, O2:H29, O2:H-, O82:H8, O82:HUT, O153:H19, O153:H42 and O153:H-. Among the isolates producing both VT1 and VT2 toxins, O153:H19 was relatively frequent. Based on findings that many bacterial strains coinciding with toxin types and serotypes of human-derived VTEC isolated from dairy cattle, it was suggested that dairy cattle are closely related to VTEC infection in human as a source of infection.

Animals↗
PubMed1999

An enzyme-linked immunosorbent assay using nuclear antigen for detection of feline herpesvirus 1 antibody.

To detect antibody against feline herpesvirus 1 (FHV-1) in the sera of cats, the sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) using nuclear antigen was investigated. The standardized optical density readings (ODs) of the ELISA obtained by the 1-step serum dilution (1:80) method were compared with the serum neutralization test (SNT) results, with a correlation of 0.993, and with the hemagglutination inhibition (HI) test results, with a correlation of 0.851. The ODs for the ELISA titers were obtained using the serial serum dilution method and were compared with the SNT results, with a correlation of 0.933, and with the HI test results, with a correlation of 0.987. In the experimental infection of 4 specific-pathogen-free cats, the results of different serologic tests (SNT and HI) and the ELISA using the serial serum dilution method revealed rapid production of antibodies after inoculation, whereas the ELISA using the one-step serum dilution method indicated that titers increased more slowly. These results indicate that with the present ELISA using nuclear antigen, there are fewer demands on time and labor, making the method convenient for monitoring FHV-1 infection.

Animals↗
PubMed1999

Rosai-Dorfman disease presenting multiple intracranial lesions with unique findings on magnetic resonance imaging. Case report.

Rosai-Dorfman disease (RDD) is a rare idiopathic histoproliferative disease affecting the systemic lymph nodes. Although an extranodal lesion has also been recognized, central nervous system involvement is extremely rare. To the authors' knowledge, only 20 cases of intracranial lesions have been reported previously. Intracranial RDD is clinically and radiologically difficult to distinguish from meningioma, and histological examination is essential for a definitive diagnosis. The authors treated a large frontal lobe tumor associated with multiple meningeal nodules in a 67-year-old patient presenting with diplopia and headache. Radiological examination indicated that the mass was an inflammatory lesion rather than a meningioma. Microscopically the lesion consisted of mixed inflammatory infiltrate with marked emperipolesis, which is characteristic of RDD. A review of the literature and a discussion of the differential diagnosis of this rare lesion are also presented.

Aged↗
PubMed1999

[Evaluation of 99mTc-MAG3 (mercaptoacetyltriglycine) renography for pediatric patients].

It is difficult to evaluate renal function with 99mTc-MAG3 renography in both adult and pediatric patients. We examined 109 pediatric patients with various renal diseases using 99mTc-MAG3 renography. Tenal diseases were classified as follows: 9 vesicoureteral reflux, 4 ureteropelvic junctional stenosis, 3 double pelvis, 23 hydronephrosis, 4 glomerulonephritis, 4 nephrotic syndrome, 24 hemolytic uremic syndrome, 10 others; and 24 patients without abnormal findings on other examinations. After hydration and sedation, 100-200 MBq of 99mTe-MAG3 was injected intravenously. All patients were placed in the supine position, and dynamic data acquisition at 12 sec/frame x 100 frames was performed from the back. The renograms were prepared with the ROIs (regions of interest) set to include the entire kidney. Tmax and T1/2 of renograms were measured for 26 kidneys with no abnormal findings. The correlations between Tmax or T1/2 and age (days after birth) were determined by a linear or logarithmic function. The logarithmic function (Y = 7.49 - 0.56 logeX, r2 = 0.134) yielded a higher correlation than did the linear function (Y = 5.16 - 0.00194X, r2 = 0.089) between Tmax and age. For T1/2 and age (days after birth), the linear function (Y = 8.07 - 0.00451X, r2 = 0.222) yielded a higher correlation than the logarithmic function (Y = 11.9 - 0.986 logeX, r2 = 0.192). Our findings suggest that prolonged Tmax is normalized more rapidly than T1/2 after birth in infants. A delayed excretion phase is not suggestive of renal dysfunction, but is characteristic of renograms in pediatric patients. Abnormality was detected in all patients with hydronephrosis using 99mTc-MAG3 renography. On the other hand, a quantitative study was required because renography detected no abnormality for some of patients with disorders of renal parenchyma.

Adolescent↗
PubMed1999

Significance of electron-dense deposits in the mitochondrial matrix of erythroid precursors in aplastic anaemia and myelodysplastic syndrome.

Recently the number of long-term survivors of aplastic anaemia has increased, with some of these cases evolving into myelodysplastic syndrome (MDS). Because it is difficult to discriminate between aplastic anaemia and hypoplastic MDS, it is unknown whether these patients have had MDS from the time of diagnosis of aplastic anaemia. Presence of ringed sideroblasts on an iron-stained bone marrow smear is a characteristic of some cases of MDS. Amorphous electron-dense deposits in the mitochondrial matrices of erythroid precursors observed with an electron microscope show ringed sideroblasts, and detection of this mitochondrial pathology is useful for confirming the presence of ringed sideroblasts because this mitochondrial pathology can be found not only in erythroblasts but also in reticulocytes, which is particularly useful in cases in which few erythroblasts are found. We found this mitochondrial pathology in two of nine children who had an initial diagnosis of aplastic anaemia and in three children with hypoplastic MDS. It is unknown at present whether the first two children had aplastic anaemia or hypoplastic MDS. Our results warrant further studies on more patients to confirm the significance of amorphous electron-dense deposits in the mitochondrial matrices of erythroid precursors.

Adolescent↗
PubMed1999

[Quantitative assessment of 201Tl-SPECT in tumors of bone and soft tissue].

201Tl-SPECT was performed to diagnose the malignancy of bone and soft tissue tumors by visual and quantitative assessment in 48 patients (17 malignant lesions and 31 benign lesions). SPECT images were obtained in the early phase (15 min after injection) and the delayed phase (240 min). By visual assessment a tumor was considered malignant if high accumulation was found in the tumor in the early phase and the accumulation was confirmed in the delayed phase. Tumors which did not meet these criteria were considered benign. For quantitative assessment, the ROI (region of interest) accumulation ratios of the tumor to the contralateral normal tissue in the early phase (ER) and in the delayed phase (DR), the ROI accumulation ratio of the delayed phase to the early phase of the tumor (Td/Te), and the ROI accumulation ratio of the delayed phase to the early phase of the contralateral normal tissue (Nd/Ne) were obtained. Sixteen patients with malignant tumors each had a high accumulation each but 12 of 31 benign lesions had no high accumulation on visual assessment. Furthermore, the accuracy was 85.4%, sensitivity 94.1%, and specificity 80.6%. Quantitative assessment was performed for 36 cases of high accumulation. The ER of malignant and benign lesions was 5.51 +/- 3.73 and 2.75 +/- 2.17, respectively, and the ER of malignant lesions was significantly higher than that of benign lesions. The DR did not demonstrate a significant difference. If the tumor having an ER greater than 3.9 was assumed to be malignant, the accuracy for differentiating malignant lesions from benign lesions was 85.4%. The Td/Te of benign lesions (0.97 +/- 0.28) was higher than that of malignant lesions (0.77 +/- 0.09). The Nd/Ne of normal tissue which contained muscles in both lesions were higher than 1.4. In conclusion, 201Tl-SPECT was very useful for the differential diagnosis of benign or malignant bone and soft tissue tumors. The ER was important for quantitative assessment, but a delayed image was necessary for visual assessment.

Adolescent↗
PubMed1999

[Endodermal cyst of the cerebellopontine angle cistern: case report].

We report a case of a 55-year-old man with endodermal cyst located in the cerebellopontine angle cistern. The patient presented with dizziness. Magnetic resonance imaging (MRI) revealed multilocular cystic lesion at the right cerebellopontine angle. T1-weighted image showed a mass with a low signal intensity, but higher intensity than CSF. Gd-DTPA T1-weighted image showed no enhancement in the mass. Diffusion-weighted image showed a mass with no signal lesion. After successful surgical removal, it was found to be an endodermal cyst. These cysts have usually been found in the spinal canal, and their intracranial occurrence is exceptional. The unusual location of the cyst and its histological features and radiological findings are discussed.

Cerebellar Diseases↗