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T Watabe

Publications and source records attributed to T Watabe.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Hyaline cartilage delineation of the knee joint using magnetization transfer contrast images].

Using a magnetization transfer contrast method (MTC), we evaluated its clinical feasibility for demonstration of hyaline cartilage of the human knee in five normal subjects. MTC images, obtained from a gradient echo sequence with an off resonance pulse, were compared with those without off resonance pulse. Signal to noise ratio (SNR) and magnetization transfer rate (MTR) were analyzed with respect to hyaline cartilage, muscle, fat, joint fluid and background noise. Also, contrast to noise ratios (CNRs) of cartilage and fluid were compared. MTRs were significantly different between cartilage-muscle group and fat-fluid group. The CNRs of cartilage and fluid were increased on MTC images, showing good contrast separation between hyaline cartilage and joint fluid.

Adolescent↗
PubMed1994

Novel theta class glutathione S-transferases Yrs-Yrs' and Yrs'-Yrs' in rat liver cytosol: their potent activity toward 5-sulfoxymethylchrysene, a reactive metabolite of the carcinogen 5-hydroxymethylchrysene.

Two novel theta class glutathione S-transferases (GSTs), designated Yrs-Yrs' and Yrs'-Yrs', were isolated from rat liver cytosol and purified to homogeneity. Polyclonal antibody raised against the previously reported theta class GST Yrs-Yrs (Hiratsuka, A. et al., J. Biol. Chem. 265, 11973 (1990)) cross-reacted with GSTs Yrs-Yrs' and Yrs'-Yrs'. These three theta class GSTs had different pI values and were separated by chromatofocusing. The enzyme subunit Yrs' was separated from Yrs by reverse partition HPLC, but identical to Yrs in the first 37 N-terminal amino acid sequence. Like GST Yrs-Yrs, both GSTs Yrs-Yrs' and Yrs'-Yrs' were not retained on an S-hexyl-GSH affinity column and had little activity toward 1-chloro-2,4-dinitrobenzene. However, they showed potent activities toward the reactive sulfate ester of the carcinogen, 5-hydroxymethylchrysene. GSTs Yrs-Yrs and Yrs'-Yrs' showed much higher GSH peroxidase activities toward arachidonate hydroperoxide than did rat liver alpha class GST Ya-Ya.

Amino Acid Sequence↗
PubMed1994

[High resolutional MR angiography of renal arteries with Gd-DTPA infusion and breath-holding].

To obtain high resolutional renal MR angiogram we combined 3D fast scanning technique with Gd-DTPA infusion and surface coil imaging in seven individuals. 1 x 2 x 4 mm spatial resolution provided excellent renal arterial images although thinner slices suffered from decreased signal to noise ratio and ghost artifacts. Twenty seconds interval between injection and data sampling was considered suitable to obtain sufficient signal of the renal arteries. Its easiness, no x-ray irradiation, and capability of repeating study make this technique promising for screening renal arterial diseases.

Adolescent↗
PubMed1994

Expression of insulin-like growth factor II by a gastric carcinoma associated with hypoglycaemia.

A gastric cancer with liver metastases was associated with low morning levels of plasma glucose (24 mg/dl), insulin (< 2.5 microU/ml) and growth hormone (0.23 ng/ml). Primary and metastatic tumour tissue stained positively with anti-insulin-like growth factor II (IGF-II) monoclonal antibody. Western immunoblot analysis revealed a high molecular weight IGF-II in the serum: 15 kDa (normal: 7.5 kDa). Postmortem reverse transcription polymerase chain reaction on mRNA from both sites revealed 471 base pairs size cDNA encoding prepro-IGF-II. These results suggest that the gastric carcinoma encoded, expressed, and secreted IGF-II, probably causing the extrapancreatic tumour hypoglycaemia.

Aged↗
PubMed1994

Molecular cloning and functions of rat liver hydroxysteroid sulfotransferases catalysing covalent binding of carcinogenic polycyclic arylmethanols to DNA.

Three sulfotransferases (STs) catalysing the metabolic activation of potent carcinogenic polycyclic arylmethanols were purified from female Sprague-Dawley (SD) rat liver cytosol without loss of their enzyme activities in the presence of Tween 20 used for preventing the enzymes from aggregation during purification and identified as hydroxysteroid sulfotransferases (HSTs). All the purified HSTs, STa, STb, and STc, with different electric charges had an apparently equal size of subunit (30.5 kDa) and cross-reacted with polyclonal antibody raised against STa. Our study on molecular cloning of cDNA libraries from two female SD rat livers indicated that both contained cDNA inserts coding for 5 different HST subunits, consisting of 284-285 amino acid residues (M(r), 33,084-33,535) and sharing strong amino acid sequence identity (> 83%). Of the 5 HST subunits, two had an identical amino acid sequence except for only one amino acid residue, and the other two contained only 6 amino acid substitutions in their sequences.

Amino Acid Sequence↗
PubMed1994

Major hydroxysteroid sulfotransferase STa in rat liver cytosol may consist of two microheterogeneous subunits.

The possible existence of two microheterogeneous subunits, designated ST-40P and ST-41P, of hydroxysteroid sulfotransferases in female Sprague-Dawley rat liver cytosol was demonstrated by cloning and sequencing of cDNAs, both isolated from two rat liver cDNA libraries. These subunits consisted of an equal number of amino acid residues with only one amino acid substitution. ST-40P and ST-41P expressed as homodimers from the ST-40 and ST-41 cDNAs in Escherichia coli had enzyme activities toward all of the examined 20 hydroxysteroids, 13 bile acids, and the carcinogen 5-hydroxymethylchrysene (5-HCR), with formation of the reactive metabolite 5-HCR sulfate, at rates very similar to those by STa, the major hydroxysteroid sulfotransferase in rat liver cytosol. This strongly suggested that they are essential components of STa. The present study carried out by using the recombinant enzymes provides the first direct evidence for the identity of sulfotransferases catalysing the sulfation of hydroxysteroids and bile acids and proposes that the current nomenclature system used for distinguishing hydroxysteroid sulfotransferases from bile acid sulfotransferases should be improved.

Amino Acid Sequence↗
PubMed1994

Intracranial aneurysms: diagnostic accuracy of three-dimensional, Fourier transform, time-of-flight MR angiography.

PURPOSE: To assess the accuracy of three-dimensional, Fourier transform, time-of-flight magnetic resonance (MR) angiography in the identification of intracranial aneurysms. MATERIALS AND METHODS: MR angiograms of 126 patients (59 male and 67 female patients, aged 12-77 years) with various intracranial vascular lesions were evaluated. Seventy-eight aneurysms, including 60 less than 5 mm in diameter, in 61 patients were depicted at conventional angiography. Eight projection images, as well as one axial collapsed MR angiogram obtained with a maximum-intensity projection algorithm, were used for evaluation. RESULTS: Sensitivity for the five observers ranged from 58% to 68% (mean, 63%). Higher sensitivity was achieved for anterior communicating and middle cerebral artery aneurysms, while that for internal carotid artery aneurysms was poor. Sensitivities for small and medium aneurysms ranged from 50% to 60% (mean, 56%) and from 77% to 94% (mean, 86%), respectively. CONCLUSION: MR angiography can depict intracranial aneurysms 5 mm or larger with good accuracy but is less useful for the identification of smaller aneurysms.

Algorithms↗
PubMed1994

Intracranial vascular stenosis and occlusion: diagnostic accuracy of three-dimensional, Fourier transform, time-of-flight MR angiography.

PURPOSE: To assess the accuracy of three-dimensional, Fourier transform, time-of-flight magnetic resonance (MR) angiography in the detection of intracranial steno-occlusive diseases. MATERIALS AND METHODS: One hundred thirty-one patients (62 male and 69 female patients, aged 6-77 years [mean, 53 years 8 months]) underwent MR and conventional angiography for evaluation of possible intracranial vascular disease. A total of 502 arteries were assessed. Eight projections and a collapsed image postprocessed by means of a maximum-intensity projection algorithm were reviewed by five observers in a blinded manner, with conventional angiography as the standard. RESULTS: A total of 32 steno-occlusive lesions were available for review. Receiver operating characteristic analysis from the pooled data revealed overall sensitivities of 85% and 88% and specificities of 96% and 97% for the internal carotid artery and the middle cerebral artery, respectively. CONCLUSION: MR angiography is useful as the primary diagnostic tool for evaluating suspected intracranial steno-occlusive disease.

Algorithms↗
PubMed1994

Existence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols in lipoproteins from diabetic patients and normal subjects.

We report evidence for the presence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols (cholesterol 7-hydroperoxides, Ch 7 alpha-OOH and Ch 7 beta-OOH, respectively) in human plasma lipoproteins in vivo, which had been reported to be markers of aging in rat skin. A comparative study was carried out focusing on the detection of Ch 7-OOHs in plasma lipoproteins from diabetic patients whose plasma has been suggested to be under high oxidative stress. Blood samples were collected from healthy volunteers (control) and diabetics with and without hypercholesterolemia. Ch 7-OOHs were isolated from low and high density lipoproteins (LDL and HDL, respectively) in the plasma of these subjects, identified, and determined by high-performance liquid chromatography with a chemiluminescence detector. The percent detection of Ch 7-OOHs in LDL from diabetics without hypercholesterolemia was similar to that in the control group. However, it was significantly higher in diabetics with hypercholesterolemia than in those without hypercholesterolemia. The percent detection of Ch 7-OOHs in HDL from diabetics without hypercholesterolemia was higher than both that in LDL from the same group and that in HDL from the control group.

Adult↗
PubMed1993

Transport pathways for macromolecules in the aortic endothelium: I. Transendothelial channels revealed by three-dimensional reconstruction using serial sections.

Three-dimensional organization of structures labeled by horseradish peroxidase as a tracer molecule in rat aortic endothelium was examined to elucidate the transport pathways for macromolecules. Aortic endothelium was divisible morphologically into four distinct parts, i.e., the parajunctional region (JR), peripheral region (PR), organelle region (OR), and nuclear region (NR). Almost all vesicles, intercellular clefts, and phagosomes were labeled by horseradish peroxidase. Peroxidase-positive vesicles tended to gather in the PR, occasional JR, and the upper part of the NR. Ultrathin serial micrographs revealed the transcellular channels composed of vesicles in the PR and JR, and the paracellular channels composed of the intercellular cleft without constrictions of tight and gap junctions. Transcellular channels were subdivided into three morphologically different types, where not only vesicles but invagination of abluminal membrane and intercellular cleft occasionally participated in their formation. Three-dimensional reconstructions from three series of consecutive electron micrographs revealed that almost all peroxidase-positive vesicles were connected directly or indirectly with the cell surface. These results indicate that the transcellular and paracellular channels are the transport pathways for macromolecules in the aortic endothelium and may suggest that the "shuttle" hypothesis is unsuitable to explain transport system for macromolecules because it postulates the existence of many free vesicles in the cytoplasm.

Animals↗
PubMed1993

Visual outcome after vitrectomy for diabetic retinopathy. A five-year follow-up.

For 5 years after surgery we measured visual acuity in 56 eyes that had undergone pars plana vitrectomy for proliferative diabetic retinopathy. A total of 44.7% eyes maintained improved visual outcome, 19.6% had unchanged visual acuity, and 35.7% were considered failures, as compared to preoperative measurements. Visual results obtained from each patient's visual acuity measured at 3 months, 6 months, 1 year, and 3 years after surgery were statistically compared with that obtained from the visual acuity at 5 years using the chi 2 test. Results showed that visual results recorded at 3 months and 6 months were significantly different from that recorded at the 5-year follow-up (p < 0.02, respectively). We found a tendency for the visual acuity to change during the initial 6 months after surgery and to stabilize by 1 year. Further analysis showed that the initial instability was due to the presence of preoperative retinal detachment. Postoperative visual functions also worsened with complications such as postoperative retinal detachment, glaucoma, and cataract formation.

Adult↗
PubMed1992

[2D MR angiography of the aortic aneurysm--effectiveness of oblique saturation pulses for selective angiogram].

2D time-of-flight MR angiography was performed in 6 cases of thoracic aortic aneurysm. Oblique saturation pulses were used to suppress the signals of the pulmonary artery and SVC, providing excellent selective MR aortograms. 3 dimensional extension of the aneurysm and its relation with cervical branches were easily assessed. It could be possible to replace invasive aortography by this technique.

Aorta, Thoracic↗
PubMed1992

Vitreous, retinal and subretinal hemorrhages associated with von Willebrand's syndrome.

Two patients with von Willebrand's syndrome had intraocular hemorrhages without trauma or neovascularization. A 13-year-old Japanese girl complained of sudden spotted vision in her left eye. Vitreous, peripapillary retinal, and subretinal hemorrhages were seen by ophthalmoscopy in the affected eye. In addition, a 19-year-old Japanese man had repeated vitreous hemorrhage and epistaxis. Also noted was gyrate atrophy of the choroid and retina. Analysis of the coagulation-fibrinolysis system revealed decreased activities of Factor VIII and von Willebrand's factor in both patients. The amount of von Willebrand's factor antigen also was decreased. These results suggested that the patients had von Willebrand's syndrome. The bleeding tendency in the disorder appeared to be responsible for the pathogenesis of the intraocular hemorrhages seen in these patients.

Adolescent↗
PubMed1992

Giant air cell of the petrous apex: a possible cause of facial hypalgesia.

A giant air cell of the left petrous apex was found in a 23-year-old man with ipsilateral facial hypalgesia. The size of the giant air cell depicted on computed tomography was 1.5 x 2.0 x 2.0 cm. A coronal T1-weighted magnetic resonance image showed that the trigeminal nerve was compressed superomedially by a large signal void area that was probably a result of excessive pneumatization of the petrous apex. It is suggested that the facial hypalgesia was caused by the compression by the giant air cell of the petrous apex on the trigeminal nerve.

Adult↗
PubMed1991

Molecular cloning and amino acid sequencing of rat liver class theta glutathione S-transferase Yrs-Yrs inactivating reactive sulfate esters of carcinogenic arylmethanols.

A cDNA containing the entire coding sequence for the subunit protein of rat liver class theta glutathione S-transferase (GST) Yrs-Yrs was isolated from a rat liver lambda gt11 cDNA library. The cDNA, designated GST theta-1, consisted of 1,258 bp which had an open reading frame of 732 bp encoding a polypeptide of 244 amino acid (AA) residues, including the leading AA Met to be removed on expression. The authenticity of the cDNA structure was supported by matching its deduced AA sequence with N-termini of Yrs and peptides obtained thereof by tryptic digestion as well as by CNBr cleavage. The deduced AA sequence of the subunit Yrs (M.W. 27,311) had only a weak homology (19-23%) with those of rat liver classes alpha, mu, and pi GST isozymes. Thus, the first evidence for the molecular cloning of the class theta GST was provided.

Amino Acid Sequence↗
PubMed1991

Occurrence of cholesterol 7 alpha- and 7 beta-hydroperoxides in rat skin as aging markers.

Evidence for presence of cholesterol 7 alpha- and 7 beta-hydroperoxides in rat skin was presented for the first time. The 7-hydroperoxides in rat skin were reduced with sodium borohydride and trimethylsilylated for identification with the authentic compounds by gas chromatography/mass spectrometry. A content of cholesterol 7-hydroperoxides in rat skin, determined by high performance liquid chromatography with a chemiluminescence detector, highly correlated with the age of rats (r = 0.874; between 1 and 45 weeks old), indicating that cholesterol 7 alpha- and 7 beta-hydroperoxides were good markers for aging.

Aging↗