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T Obayashi

Publications and source records attributed to T Obayashi.

At least 19 recordsLinked to original sources
PubMed2006

In silico assessment of gene function involved in cysteine biosynthesis in Arabidopsis: expression analysis of multiple isoforms of serine acetyltransferase.

In plants, the inorganic sulfur is first fixed into cysteine by the cysteine biosynthetic pathway. This biosynthetic pathway of cysteine involves several enzymatic reactions. In Arabidopsis thaliana, multiple isoforms seem to participate in each enzymatic step for cysteine biosynthesis. To obtain more insights on the specific role of each isoform involved in the cysteine biosynthesis, in silico analysis of these isoforms using Arabidopsis expressed sequence tags (EST) database was carried out. This EST database analysis revealed distinct population distribution of ESTs among multiple isoforms, suggesting that each isoform has its particular expression pattern, presumably associated with its specific role in cysteine biosynthesis. As another in silico analysis, co-expression analysis of genes involved in sulfur metabolism in Arabidopsis was performed using a public transcriptome database of DNA microarrays. This co-expression analysis also suggested specific function and co-regulation of some isoform genes for cysteine biosynthesis by consideration on the clustering of co-expressed genes. From the results of sensitivity to feedback regulation, subcellular localization and expression of mRNA analyses, each serine acetyltransferase (SATase) isoform seems to have its specific role for cysteine biosynthesis. Similar expression patterns were observed between the experimental results of expression data for SATase isoforms and the in silico results of "digital northern" analysis using EST database.

Arabidopsis↗
PubMed2002

Polyclonal nature of diffuse proliferation of interstitial cells of Cajal in patients with familial and multiple gastrointestinal stromal tumours.

BACKGROUND: Diffuse proliferation of interstitial cells of Cajal (ICCs) in the myenteric plexus layer of the intestine has been described in patients with familial and multiple gastrointestinal stromal tumours (GISTs). However, it is not fully understood whether proliferation is polyclonal or monoclonal. AIMS: To evaluate the clonal nature of diffuse ICC proliferation in familial and multiple GIST cases, we carried out clonal analysis using inactivation at the human androgen receptor (HUMARA) locus. MATERIALS AND METHODS: Diffuse ICC proliferation tissues from three female patients were microdissected using a laser capture microdissection (LCM) system. Normal intestinal mucosal tissues were also microdissected for polyclonal controls and GIST tissues for monoclonal controls from the same patients, and genomic DNA was extracted. After digestion by restriction enzyme HhaI, the HUMARA locus was amplified by a fluorescent polymerase chain reaction (PCR) procedure and the PCR products were analysed. RESULTS: One case was uninformative because it was homozygous at the HUMARA locus. In the two other cases, PCR products from the diffuse ICC proliferation showed two alleles as well as those from normal intestinal mucosal tissues, indicating that ICC proliferation was polyclonal. In contrast, PCR products from associated GIST tissues showed only one allele, indicating that GISTs were monoclonal. CONCLUSION: The results suggested that diffuse ICC proliferation in familial and multiple GIST cases was non-neoplastic hyperplasia.

Cell Division↗
PubMed2001

Transient QT interval prolongation with inverted T waves indicates myocardial salvage on dual radionuclide single-photon emission computed tomography in acute anterior myocardial infarction.

In patients with acute myocardial infarction (AMI), transient QT interval prolongation with a prominent negative T wave is frequently observed in cases of early spontaneous reperfusion and often indicates a good prognosis. Additionally, in nuclear cardiac imaging, technetium-99m/thallium-201 overlap on dual single-photon emission computed tomography (dual SPECT) in AMI patients indicates the presence of viable myocardium and early recanalization. To elucidate the clinical significance of this transient QT interval prolongation, 34 patients (64 +/- 8 years) admitted within 24h of the onset of anterior AMI were enrolled and classified into 2 groups according to the presence (group A, n=24) or absence (group B, n=10) of scintigraphic overlap on simultaneous dual SPECT imaging. The maximal QTc interval was 0.59 +/- 0.06 s in group A and 0.52 +/- 0.06 s in group B (p<0.01). The peak creatine kinase was lower in group A (2650 +/- 2160 IU/L) than in group B (3490 +/- 2060 IU/L). The left ventricular ejection fraction (LVEF) at discharge was 62 +/- 11% in group A and 49 +/- 14% in group B (p<0.01). The scintigraphic overlap group had a smaller infarct and better LVEF, which suggests that the QT interval prolongation that appears transiently in the acute phase of AMI indicates scintigraphically the presence of salvaged myocardium.

Aged↗
PubMed2001

[A case of free-floating ball thrombus in left atrium with mitral stenosis].

We report a rare case of free-floating ball thrombus in the left atrium with mitral stenosis. The patient was 71-year-old woman who admitted to the local hospital for transient ischemic attack. Electrocardiography showed atrial fibrillation and an echocardiogram examination revealed free-floating ball thrombus in the left atrium with mitral stenosis. She was transferred to our hospital for emergency open heart operation. After removal of the ball thrombus, mitral valve replacement and modified MAZE procedure were successfully performed. The size of the ball thrombus was 40 x 30 x 33 mm and weighed 20 g. Postoperative course was uneventful.

Aged↗
PubMed2000

Non-culture based diagnostic tests for mycotic infections.

Non-culture methods being developed and evaluated for mycotic infections include polymerase chain reaction (PCR), galactomannan (GM) antigenemia, Western blot (WB) to detect antibodies, and detection of the fungal metabolites D-arabinitol and (1,3)-beta-D-glucan. Sample preparation for PCR from blood specimens depends on fractionation of peripheral blood, its pre-incubation in blood culture broth, or a total DNA method, which does not rely on fractionation, or pre-incubation. Targets for PCR of fungi in the 18S or ITS2 subunits of the ribosomal RNA genes facilitated the design of Aspergillus and Candida genus and species probes. Amplicons were identified using PCR-enzyme linked immunosorbent assay (ELISA) or reverse line-blot formats. A pilot study indicated that PCR tests on blood specimens were positive at least once in patients with confirmed invasive aspergillosis (IA). When serum-PCR and serum-GM tests were compared in IA patients, antigenemia was more often positive. PCR detected Aspergillus DNA in bronchoalveolar lavage specimens from patients at risk even when cultures were negative. D-Arabinitol can be detected as a marker of candidiasis with gas chromatography-mass spectrometry or enzyme dependent-fluorometry. Each method can differentiate the microbial D- and host L-enantiomers. (1,3)-beta-D-Glucan is produced by most genera of pathogenic fungi and can be detected in plasma by the 'G-test'. In patients with febrile neutropenia the efficacy of azole therapy correlated with plasma (1,3)-beta-D-glucan concentrations of > or = 10 pg ml(-1). The diagnosis of early acute pulmonary histoplasmosis can be improved by a WB test utilizing deglycosylated M antigen, a 94-kDa glycoprotein. The identity of M antigen as a catalase was deduced from the sequence of the cloned gene. PCR identification of Histoplasma capsulatum cultures was accomplished with primer pairs selected from H and M antigen gene sequences.

Antibodies, Fungal↗
PubMed1999

Postencephalitic focal retrograde amnesia after bilateral anterior temporal lobe damage.

BACKGROUND: Marked retrograde amnesia with no or almost no anterograde amnesia is rare. Recently, a combination of ventrolateral prefrontal and temporopolar cortical lesions has been suggested as the cause of such isolated or focal retrograde amnesia. It is also assumed that when the right-sided cortical structures are damaged, autobiographical episodic memories are affected. OBJECTIVE: To search for new anatomic substrates for focal retrograde amnesia. METHODS: We performed extensive neuropsychological tests and obtained detailed neuroimages on a 43-year-old woman who showed a severe, persistent retrograde amnesia but only a limited anterograde amnesia after probable herpes simplex encephalitis. RESULTS: Tests of autobiographical memory revealed that she had a memory loss extending back to her childhood for both semantics and incidents; however, the ability to recall specific episodes appeared much more severely impaired than the ability to recall factual information about her past. The patient also showed profound impairments in recalling public memories; however, her scores improved nearly to a control level on forced-choice recognition memory tasks, although the recall of memories for a decade just before her illness remained mildly impaired. MRI revealed focal pathologies in the temporal poles and the anterior parts of the inferotemporal lobes on both sides, predominantly on the left, with some extension to the anterior parts of the medial temporal lobes. There was additional damage to the left insular cortex and its surrounding structures but no evidence of frontal lobe damage on MRIs or cognitive tests. CONCLUSIONS: A profound retrograde amnesia may be produced by damage to the bilateral temporal poles and anterior inferotemporal lobes in the absence of frontal lobe pathologies, and a dense and persistent episodic old memory loss can arise even with a relatively small lesion in the right anterior temporal lobe if it is combined with extensive damage to the left.

Adult↗
PubMed1999

Molecular epidemiological study on tetracycline resistance R plasmids in enterohaemorrhagic Escherichia coli O157:H7.

Restriction patterns obtained with EcoRI and Southern hybridization were used for the differentiation of tetracycline-resistant (Tet(r)) R plasmids in enterobaemorrhagic Escherichia coli (EHEC) O157:H7 isolates from a mass outbreak at a kindergarten in Obihiro-City, Hokkaido, Japan, 1996. Two kinds of Tet(r) R plasmids of 50 and 95 kb were detected. The 50-kb plasmids were identical to each other, while the 93-kb plasmids were of three types that were very similar to each other. The tet genes of both 50- and 95-kb R plasmids were 100% identical to the tet gene of pSC101 and all plasmids hybridized to a probe for tet. Because food-origin O157 strains were sensitive to tetracycline, we concluded that such Tet(r) R-plasmids might transfer to drug-sensitive O157 strains in the infected individuals.

Anti-Bacterial Agents↗
PubMed1999

[Mapping-guided focal cryoablation and endoaneurysmorrhaphy for a case of ischemic ventricular tachycardia with left ventricular aneurysm].

A 74-year-old woman admitted with exertional dyspnea. Echocardiography revealed the giant left ventricular aneurysm. In the hospital course, she fell into sustained monomorphic ventricular tachycardia. Coronary angiogram showed complete obstruction of the LAD. Left ventricular ejection fraction was 20%. The origin of tachycardia seems to be at infero-apicallateral area of LV by electrophysiology study. Because of the failure of RF energy ablation, we planned mapping-guided cryoablation, CABG and endoaneurysmorrhaphy. To prevent air embolism and myocardial ischemic damage for long aortic cross clamp, intraoperative endocardial mapping was carried out on beating heart due to continuous normothermic coronary blood perfusion (300 ml/min) from the aortic root cannula under aortic clamping. Cold crystalloid cardioplegia changed into the root cannula after EPS, focal cryoablation (-100 degrees C) was performed 3 times on cardiac arrest. Sustained VT was not inducible in the following study. CABG and endoaneurysmorrhaphy was performed on repeated cardiac arrest during single aortic clamp. Postoperative course was uneventful, and she discharged 8 weeks after the operation.

Aged↗
PubMed1999

[Non-culture based laboratory diagnosis of sepsis].

Blood culture is clearly the most important diagnostic procedure for sepsis. In the majority of cases, however, it yields negative results when bacterial or fungal sepsis is strongly suspected in view of an excellent response to antibacterial or antifungal medication. This is likely because infecting microbes have already been too seriously damaged in the blood stream to grow in culture media. Therefore, various tests have been devised to detect cellular components of pathogens including endotoxin for gram-negative bacteria, (1-->3)-beta-D-glucan for fungi, a non-mannan heat-labile candida antigen, glucronoxylomannan for Cryptococcus neoformans, and galactomannan for Aspergillus. The first two tests are particularly suitable for screening purposes, because, in addition to their high sensitivity and specificity, they cover a wide range of species in each category, though not as widely as blood culture. The candida antigen detectable by Candi-Tec is probably a complex of immune-related proteins, and appears to be a poor indicator in immunocompromised hosts. Glucronoxylomannan has been established as a useful marker of cryptococcosis, whereas galactomannan, though highly specific for aspergillosis, needs a more sensitive detection system to be useful for diagnostic purposes.

Bacteremia↗
PubMed1998

Primary antiphospholipid syndrome with acute myocardial infarction recanalised by PTCA.

A 20 year old man with severe chest pain was hospitalised for acute myocardial infarction. Coronary angiography revealed total obstruction of his right coronary artery, which was successfully recanalised by direct percutaneous transluminal coronary angioplasty (PTCA). There was also diffuse thrombi in the left coronary artery that was not recanalised by perfusion with 3000 U pro-urokinase. Anticoagulant therapy was performed after PTCA. Creatine kinase peaked one day after hospitalisation (4805 U/l). The activated partial thromboplastin time was 62.6 seconds (45%). Plasma anticardiolipin IgG antibodies were high (3.8 and 2.7) in repeated examinations. The PTCA site was patent after three months. Primary antiphospholipid syndrome should be considered as a cause of acute myocardial infarction in young adults, and PTCA with anticoagulant treatment is effective for initial treatment of the syndrome.

Adult↗
PubMed1998

[Aortic regurgitation with stenosis due to congenitally bicuspid valve with fibrous band: a surgical case report].

A 62-year-old man with aortic regurgitation and stenosis underwent aortic valve replacement. Intraoperative findings showed fibrous band between the edge of the raphe and the ascending aorta. Such fibrous bands are usually observed in juvenile pure aortic valve regurgitation due to congenitally bicuspid valve with degenerative change and are related to cause aortic insufficiency. The present patient was comparatively old, and the aortic regurgitation was combined with stenosis, which revealed sclerotic change on histological examination.

Aortic Valve↗
PubMed1998

Current trends in the detection of antigenaemia, metabolites and cell wall markers for the diagnosis and therapeutic monitoring of fungal infections.

There have been several recent developments in the diagnosis of fungal infections, including the production of novel antigen detection tests, the G-test, and assays for the detection of fungal metabolites. In this article we present an overview of these developments and examine the value of including these tests in clinical trials.

Antigens, Fungal↗
PubMed1997

Comparative ultrasonographic and angiographic study of carotid arterial lesions in Takayasu's arteritis.

The purpose of this study was to compare the usefulness of ultrasonography to that of angiography for studying arterial lesions in Takayasu's arteritis. Ultrasonographic and angiographic findings from 44 carotid arteries of 22 patients with Takayasu's arteritis (2 men and 20 women; mean age, 41.2 years) were compared. Angiography was used to classify the patency of the carotid arteries into three groups: nonstenotic, stenotic, and occlusive. Ultrasonography was also used to classify the same arteries into four groups: nonstenotic, mildly stenotic, moderately stenotic, and occlusive. Thickness of the wall (intima-media complex) of the carotid artery was measured with high-frequency transducers. Angiography showed 23 carotid arteries to be nonstenotic; 12, stenotic; and 9, occlusive; whereas ultrasonography showed 16 to be nonstenotic; 18, mildly stenotic; 7, moderately stenotic; and 3, occlusive. Results of the two diagnostic modalities correlated closely (P < 0.0001). Ultrasonography, aided by color flow imaging, detected six instances of a marginal but definite blood flow that angiography had failed to reveal. Arterial wall thickness correlated closely with the severity of ultrasonographic stenosis (P < 0.005). This thickness was 1.3 +/- 0.4 mm in the nonstenotic group, 1.6 +/- 0.5 mm in the mildly stenotic group, 2.2 +/- 0.8 mm in the moderately stenotic group, and 1.9 +/- 0.2 mm in the occlusive group. Even the walls of the nonstenotic arteries were significantly thicker than those of the normal carotid arteries (0.7 +/- 0.1 mm, P < 0.01). Ultrasonography appeared to be more useful than angiography in estimating stenotic severity of the carotid artery in Takayasu's arteritis. Characteristic ultrasonic findings included luminal stenosis or occlusion on two-dimensional ultrasonograms, decrease in or lack of flow shown by color Doppler flow imaging, and concentric thickening of the carotid arterial walls. Ultrasonographic mural thickness was the most sensitive indicator of early, latent inflammation.

Adult↗
PubMed1997

[Surgical treatment of malignant hemangioendothelioma originated from the right atrium: a case report].

A 32-year-old man was admitted to our hospital because a cardiac tumor had been pointed out by a physician. CT scans showed a mass lesion with irregular patterns in the right atrium. The patient had the diagnosis of a malignant cardiac or pericardial tumor and an operation was performed. The mass originated from the right atrium included massive coagulated blood, and was resected with the pericardium and the right pleura. The histological diagnosis was malignant hemangioendothelioma. We present this case because only 35 patients with cardiac malignant hemangioendothelioma were reported in Japan.

Adult↗
PubMed1997

[A case report of type A dissection of the aorta presenting as a superior vena cava syndrome 10 years after aortic valve replacement].

Aortic dissection usually result in chest pain and back pain. This patient is a 58 year-old man who received aortic valve replacement for aortic regurgitation 10 years ago. In this case, the patient had superior vena cava syndrome as a result of a painless aortic dissection. The superior vena cava was compressed by the ascending aorta itself, which had become very large but had not ruptured into the mediastinum. He underwent modified Carbrol's operation under hypothermic cardiopulmonary bypass and circulation arrest on May 8, 1995. Dissecting aneurysm in the late term after aortic valve replacement is rare, and for it to result in superior vena cava syndrome is especially rare.

Aortic Dissection↗
PubMed1997

Plasma (1-->3)-beta-D-glucan assay and immunohistochemical staining of (1-->3)-beta-D-glucan in the fungal cell walls using a novel horseshoe crab protein (T-GBP) that specifically binds to (1-->3)-beta-D-glucan.

A highly sensitive enzyme-linked immunosorbent assay specific to (1-->3)-beta-D-glucans (GBP-ELISA) has been developed using a novel (1-->3)-beta-D-glucan-binding protein (T-GBP), which was purified from the amebocyte lysate of the Japanese horseshoe crab, Tachypleus tridentatus. This method allowed quantitation of the glucans in a concentration range of 0.1-1,000 ng/ml, regardless of linear and branched structures, and was applied to determine the amounts of (1-->3)-beta-D-glucan in human and animal plasmas for diagnosis of fungemia. High levels of plasma glucan contents in clinical samples were found to be correlated closely with the severity of fungal infection. T-GBP was successfully utilized for indirect immunofluorescence staining of (1-->3)-beta-D-glucan in Candida albicans cell walls.

Animals↗
PubMed1997

Differentiation of renal cell carcinomas from angiomyolipomas by ultrasonic frequency dependent attenuation.

PURPOSE: We determined the usefulness of ultrasonic frequency dependent attenuation in differentiating hyperechoic renal cell carcinoma from angiomyolipoma. MATERIALS AND METHODS: Frequency dependent attenuation values were determined in 29 renal cell carcinomas and 13 angiomyolipomas. RESULTS: Frequency dependent attenuation values were significantly lower in renal cell carcinomas than in angiomyolipomas (0.42 versus 0.76 dB./cm./MHz.). Two of the renal cell carcinomas were as hyperechoic as the angiomyolipomas but they were clearly differentiated by the low frequency dependent attenuation. Two other renal cell carcinomas exhibited high values because of the abundance of fibrous tissue. However, they were readily diagnosed by the typical low echoic B-mode images. Frequency dependent attenuation did not differ between histological types of renal cell carcinoma. One angiomyolipoma that was poor in fat and rich in muscle components had an exceptionally low frequency dependent attenuation. Therefore, frequency dependent attenuation values can be regarded as an inversion of computerized tomography numbers. CONCLUSIONS: Frequency dependent attenuation measurement is a promising diagnostic aid in differentiating hyperechoic renal cell carcinomas from angiomyolipomas.

Adult↗