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Biomedical subjects

Y Suto

Publications and source records attributed to Y Suto.

At least 55 records · Page 3Linked to original sources
PubMed1997

A case of rest angina due to microvascular spasm.

A 66-year-old woman underwent elective cardiac catheterization for investigation of periodic attacks of chest pain at rest. During the examination, a chest pain attack occurred unexpectedly, resulting in ST elevation in the precordial leads on electrocardiography. Immediate coronary arteriography demonstrated no organic stenosis but markedly delayed contrast medium perfusion in the mild to distal portion of the left anterior descending artery. These phenomena spontaneously disappeared about 3 min later, and the patient was diagnosed as having angina pectoris due to microvascular spasm. The demonstration of angina pectoris due to microvascular spasm by coronary arteriography during a spontaneous attack is very rare.

Aged↗
PubMed1997

Optimum conditions for iron colloid enhanced fast spin echo imaging in hepatocellular carcinoma.

The optimum conditions for iron colloid enhanced fast spin echo (FSE) in the detection of hepatocellular carcinoma have not been clearly established as yet. MRI was performed on 14 patients with hepatocellular carcinoma (45 nodules) before and after administration of chondroitin sulphate iron colloid (CSIC). One type of conventional spin echo (CSE) (TR/TE = 1800/80) was then quantitatively and qualitatively compared with three types of FSE (FSE 1800 (TR/effective TE/echo factor = 1800/90/7); FSE 7 (3500/90/7); and FSE 11 (3500/99/11)). The liver signal-to-noise ratio (SNR) was significantly decreased after CSIC administration in all sequences, while the tumour-to-liver contrast-to-noise ratio (CNR) was significantly increased. Although the decreased ratio of the liver SNR was smaller on the three FSE sequences compared with CSE, the increased ratio of the tumour-to-liver CNR was higher on the FSE sequences. The highest increase of the tumour-to-liver CNR was on the FSE 7 sequence. The number of detectable tumours, both before and after the administration of CSIC, was largest on FSE 7. In conclusion, FSE with longer TR and TE, and decreased echo factor, was especially useful for CSIC enhanced liver MRI.

Adult↗
PubMed1997

MRI appearances of fascioliasis complicating liver iron overload.

A case of hepatic fascioliasis with an unusual appearance on MRI due to liver iron overload is presented. The diagnosis of fascioliasis was based on positive serological tests and the presence of eggs in the bile. Hepatic lesions of fascioliasis exhibited hyperintense signals on T1 weighted images as well as proton density and T2 weighted images. Histological study of biopsy specimens from the lesions showed central necrosis and peripheral fibrosis with inflammatory cells including eosinophils. Abundant iron deposition in hepatocytes and Kupffer cells was found in specimens from the surrounding liver. These findings suggested that this appearance on MR images was probably due to a decrease in signal intensity in surrounding liver.

Fascioliasis↗
PubMed1997

[Estimation of myocardial viability and clinical significance of reverse redistribution in resting technetium-99m sestamibi myocardial single photon emission computed tomography in patients with acute myocardial infarction].

The clinical significance of reverse redistribution of technetium-99m sestamibi (MIBI) was investigated in 36 patients with acute myocardial infarction and angiographically confirmed single-vessel disease, but without previous infarction using resting MIBI myocardial single photon emission computed tomography (SPECT) and exercise-reinjection thallium-201 (Tl) myocardial SPECT. MIBI myocardial SPECT was performed 90 min and 300 min after injection of MIBI 370 MBq at rest. Four hours after exercise Tl imaging was completed, reinjection imaging was obtained. Wall motion abnormalities on left ventriculograms were analyzed at the onset of infarction and 1 month later. The severity scores on the MIBI early image, MIBI delayed image and Tl reinjection image were 98 +/- 18, 170 +/- 22 and 90 +/- 18, respectively. The reverse redistribution of MIBI was marked in acute infarction. A significant correlation of severity score was found between the MIBI early image and Tl reinjection image (r = 0.89). In 18 patients with significant stenosis of an infarct-related artery, there was a significant correlation between the degree of reverse redistribution and that of Tl redistribution (r = 0.826). A good correlation was found between the severity score on the MIBI early image and wall motion abnormality at 1 month after infarction (r = 0.816). There was a significant correlation between the degree of reverse redistribution and wall motion improvement (r = 0.782). Despite stenosis of the infarct-related artery, the wall motion abnormality was less in 22 patients with marked reverse redistribution (defect score on the MIBI delayed image was double that on the early image) than the other 14 patients. In conclusion, the MIBI early image may reflect myocardial viability and the reverse redistribution of MIBI was observed frequently in patients with acute myocardial infarction. Marked reverse redistribution was observed in patients with preserved left ventricular function. Because of the close correlation of reverse redistribution with Tl redistribution and wall motion improvement, reverse redistribution of MIBI is considered to occur in areas at risk for acute myocardial infarction.

Adult↗
PubMed1996

TEL-AML1 translocations with TEL and CDKN2 inactivation in acute lymphoblastic leukemia cell lines.

The t(12;21) (p 13; q22) results in the fusion of the TEL gene located on chromosome 12 with the AML1 gene located on the derivative chromosome 21. Because this translocation is difficult to detect using standard cytogenetic techniques, 27 previously karyotyped B-lineage acute lymphoblastic leukemia (ALL) cell lines were evaluated for the presence of the TEL-AML1 fusion using the reverse transcriptase-polymerase chain reaction (RT-PCR), fluorescence in situ hybridization (FISH), and cDNA sequencing. Six cell lines expressed the TEL-AML1 chimeric transcript by RT-PCR and the t(12;21) was confirmed by FISH analysis with probes for TEL, AML1, and chromosome 12. While only one of the 6 cell lines with the t(12;21) lost the der(12)t(12;21)-encoded AML1-TEL fusion transcript, 4 cell lines lacked expression of the nontranslocated allele of TEL and 5 cell lines lacked expression of CDKN2. Moreover, in 2 patients (1 with the TEL-AML1 transcript and 1 without), TEL expression was lost with disease progression; le, TEL was expressed in the initial cell lines (established at diagnosis or first relapse) whereas TEL was not expressed in the cell lines established from these patients in late-stage disease. These data show the coexistence of multiple genetic defects in childhood B-lineage ALL Cell lines with t(12;21) will facilitate the study of TEL-AML1 and AML1-TEL fusion proteins as well as TEL and CDKN2 gene inactivation in leukemia transformation and progression.

Base Sequence↗
PubMed1996

Visual demonstration of the organization of the human complement C4 and 21-hydroxylase genes by high-resolution fluorescence in situ hybridization.

We analyzed the gene organization in the complement component C4 and 21-hydroxylase (21OH) gene region of the human major histocompatibility complex using visual mapping of stretched DNA by multicolor fluorescence in situ hybridization (FISH). Normally, this region contains a duplicated 21OH-C4 gene cluster (21OHB-C4B-21OHA-C4A). Duplication and deletion of one or more copies of the 21OH-C4 gene unit are known to occur frequently. Biotin-labeled cDNA of the C4 gene and digoxigenin-labeled cDNA of the 21OH gene were hybridized to decondensed nuclei of peripheral blood lymphocytes obtained from individuals with various 21OH-C4 haplotypes. Hybridization signals of the C4 and 21OH probes were detected with fluorescein isothiocyanate (green) and rhodamine (red), respectively. Two linear green and red signal clusters were observed in each nucleus showing the normal haplotype. Gene duplication and deletion were visualized as addition and deletion of the signal cluster, respectively. The DNA types of the 21OH-C4 region determined by FISH were concordant with the results previously obtained by conventional molecular studies. Our high-resolution FISH technique is found to be useful for screening gene duplications and deletions.

Complement C4↗
PubMed1996

Experimental acute dorsal compression of cat spinal cord: correlation of magnetic resonance signal intensity with spinal cord evoked potentials and morphology.

STUDY DESIGN: Acute dorsal compression of the spinal cord was applied to adult cats, and magnetic resonance signal intensity, spinal cord evoked potentials, and morphologic changes of the spinal cord were examined after 5 hours. OBJECTIVES: The present study investigated the correlation of magnetic resonance signal intensity with spinal cord evoked potentials and spinal cord morphology after 5 hours of spinal cord compression in cats. SUMMARY OF BACKGROUND DATA: Neurologic prognosis of the injury might be predicted by an analysis of magnetic resonance signal intensity pattern. Little information is available on relationships between magnetic resonance images and functional or morphologic damage of spinal cord in acute animal experiments. METHODS: Acute dorsal compression of the spinal cord was performed in 24 anesthetized cats. After laminectomy, the L2 segment was compressed for 5 hours. Spinal cord evoked potentials were recorded by electrodes placed in the epidural space at L4, and the spinal cord was stimulated at T12. The animals were divided into four groups based on changes in the amplitude of spinal cord evoked potentials. Immediately after compression for 5 hours, magnetic resonance images were obtained. Signal intensity of the spinal cord was measured on sagittal midline images. Morphologic changes were assessed. RESULTS: Spinal compression significantly increased the signal intensity of the L1, L2, and L3 segments on T2-weighted and proton density-weighted images. The increase in signal intensity was remarkable in the animals whose spinal cord evoked potentials were reduced greatly (< 40% of the control group). Histologically, edema was present in the high intensity area on T2-weighted and proton density-weighted images. CONCLUSIONS: In summary, the present study documents that spinal compression causes tissue edema, which produces high signal intensity on magnetic resonance imaging. The magnetic resonance signal intensity is correlated closely with decreased amplitude of spinal cord evoked potentials.

Acute Disease↗
PubMed1996

Sleep apnea syndrome: comparison of MR imaging of the oropharynx with physiologic indexes.

PURPOSE: To compare magnetic resonance (MR) imaging of the oropharynx in patients with sleep apnea syndrome with fiberoptic nasopharyngoscopy, and oropharyngeal pressure and apnea index values. MATERIALS AND METHODS: After sleep induction, 24 patients with sleep apnea syndrome and nine patients with non-sleep-apnea snoring underwent MR imaging and fiberoptic nasopharyngoscopy combined with subsequent measurement of oropharyngeal pressure. Patients were previously classified with apnea index values obtained at polysomnography. MR imaging and fiberoptic nasopharyngoscopic findings of severity and location of oropharyngeal abnormalities were compared. Oropharyngeal pressure and apnea index values were also compared with MR findings. RESULTS: A statistically significant correlation was observed between MR and fiberoptic nasopharyngoscopic findings (r = .931; P < .0001). The degree of decompression in oropharyngeal pressure and apnea index values in the multiple-site abnormality group were statistically significantly higher than those in the single-site abnormality group. CONCLUSION: MR imaging is useful for localization of sites of oropharyngeal abnormalities and for evaluation of the severity of apnea.

Adult↗
PubMed1996

Sleep apnea syndrome. Examination of pharyngeal obstruction with high-speed MR and polysomnography.

PURPOSE: We attempted to determine the usefulness of high-speed MR imaging for evaluating the severity of sleep apnea syndrome (SAS) by comparing findings of pharyngeal obstruction obtained with high-speed MR with those of all-night polysomnography (PSG). SUBJECTS AND METHODS: A total of 33 patients with SAS underwent turbo-FLASH MR examination, while awake and after i.v. injection of hydroxyzine hydrochloride. Serial images were examined by cinemode. Pharyngeal findings on MR were divided into single-site obstruction (SO) at the velopharynx, multiple-site obstruction (MO), and no obstruction (NO). PSG findings were analyzed to determine the predominant type of apnea, severity as evaluated by an apnea index (AI), and the lowest SaO2 value during sleep. RESULTS: Seventy-five percent of the central apnea group had SO, and 70% of the mixed apneas had MO, while only 15% of the obstructed apneas had MO. The percentage of patients with severe SAS (AI of 20% or higher) was 48% for the SO, and 70% for the MO. The lowest SaO2 value tended to be low in the mixed apnea in the case of PSG, and tended to be low in the MO at MR examination. CONCLUSION: Analysis of pharyngeal dynamics using high-speed MR may provide some useful information for evaluating the severity of SAS.

Aged↗
PubMed1996

Time-course changes of contrast enhancement in iron colloid enhanced MRI in patients with hepatocellular carcinoma.

Time-course changes in contrast enhancement of chondroitin sulphate iron colloid (CSIC), an MR contrast agent, were determined in 12 patients with 20 lesions of classical hepatocellular carcinoma (HCC). Spin echo T1 weighted (T1WI) and T2 weighted images (T2WI) were obtained before administration of CSIC and 1, 6 and 24 h after injection. The signal-to-noise ratio (SNR) in the tumour region and the liver and the tumour-to-liver contrast-to-noise ratio (CNR) were calculated, and time-course changes of these ratios were determined. SNRs for tumour before the administration of contrast medium did not differ significantly from SNRs after administration on T1WI or T2WI. SNRs for the liver on both T1WI and T2WI were significantly lower at each time point after administration than before administration. The tumour-to-liver CNRs for both T1WI and T2WI were significantly higher after administration than before administration. The maximum CNR was observed 6 h after administration on both T1WI and T2WI. The contrast enhancement was maintained for at least 24 h, with a peak at 6 h after administration. The prolonged enhancement obtained with CSIC has extended the time during which effective contrast is maintained.

Aged↗
PubMed1996

Effects of microwave tissue coagulation on the livers of normal rabbits: a comparison of findings of image analysis and histopathological examination.

The livers of normal rabbits were subjected to microwave tissue coagulation (MTC), and comparison was made of the subsequent time-course changes in tissue observed on MRI, CT and histopathological examination. 16 rabbits were used. MTC was performed with a 21 gauge needle electrode inserted into the liver at laparotomy. 1-2 h after thermal coagulation, a region with slightly lower attenuation than that of surrounding normal liver parenchyma was observed on CT, and no enhancement was detected. With MRI, change from high signal intensity to iso-signal intensity from the inner zone to the margin was found on T1 weighted images (T1WI), and heterogeneous high signal intensity was observed on T2 weighted images (T2WI). On Gd-DTPA enhanced MRI, no enhancement occurred. 1-4 weeks after coagulation, the cellular structure at the site of coagulation was lost on histological examination, and the tissue became necrotic. On CT, homogeneous water density was observed, and no enhancement was detected. With MRI, regions of iso- or slightly low signal intensity were observed on T1WI, and regions of heterogeneous high to low signal intensity were seen on T2WI. After 1 week, a granulation layer consisting mainly of fibrous tissue developed, and a ring-shaped enhancement was observed in the low signal intensity region on T1WI and in the high signal intensity region on T2WI. The ring-shaped enhancement was also noted on CT. MRI appears to be useful for observation of time-course changes following MTC therapy because of its sensitivity in the detection of tissue changes.

Animals↗
PubMed1996

MRI of the pharynx in young patients with sleep disordered breathing.

15 patients, aged 1-14 years, with sleep disordered breathing underwent turbo fast low angle shot MRI during drug-induced sleep. The site of obstruction within the pharynx was identified. Data from MRI were compared with fibroscopic findings. The degree of hypertrophy of the palatine tonsils as determined by MRI was also compared with that determined by visual inspection while awake. MRI was completed in all cases, whereas fibroscopy was completed in only six of the 10 cases examined. MRI findings agreed with those of fibroscopy in all the patients who underwent both investigations. On MRI, the pharynx was obstructed in 12 of the 15 cases examined (80%); the palatine tonsils were involved in all of these while both the palatine tonsils and nasopharynx were obstructed in three of the 12 cases. One of the 12 patients was graded as Grade I of Mackenzie's scale. One of the cases graded as Grade II showed no obstruction. In conclusion, fast MRI proved useful in identifying the site of pharyngeal obstruction in young patients with sleep disordered breathing.

Adolescent↗
PubMed1996

Usefulness of iron colloid-enhanced MRI in differentiating experimental hepatocellular carcinoma from hyperplastic nodules in rats: analysis by microautoradiography.

To demonstrate the usefulness of iron colloid-enhanced MR images in differentiating hepatocellular carcinoma (HCC) from hyperplastic nodules (HN), microautoradiographs of chemically induced rat liver tumours were prepared 4 h after intravenous injection of chondroitin sulphate iron colloid (CSIC) labelled with 59Fe by the dipping technique. 20 Wistar rats were allocated into three groups: (1) a normal group, 10; (2) an HN group, 5; and (3) a liver cancer (LC) group, 5. In the I.C group, a diet containing 0.06% 3'-methydiaminobenzine tetrahydro-chloride (DAB) was administered for 3 months. In the HN group, a diet containing 0.025% acetylaminofluorene (AAF) was administered for 4 months. Non-labelled CSIC was intravenously injected into five rats in the normal group, and pseudomicroautoradiographs were prepared using the same technique (normal cold group). 50 sites for examination were randomly selected for each of the normal liver tissue, HN, well-differentiated HCC (HCC-W), and moderately to poorly-differentiated HCC (HCC-MP). The number of Kupffer cell-like macrophages and the photosensitized area ratio (PAR) per field of view were calculated. There was no significant difference in either the number of Kupffer cell-like macrophages or the PAR between HN and normal liver tissue. Although there was no significant difference in the number of these cells between groups HN and HCC-W, the PAR in group HCC-W was significantly lower than that in group HN (p = 0.045). In HCC-MP, both their number (p = 0.003) and the PAR (p = 1.18 x 10(-9)) were significantly lower than in group HCC-W. However, the PAR in HCC-MP was significantly higher than those in the normal cold group (p = 0.019). Iron colloid-enhanced MRI is useful for differentiating HCC from HN, and for diagnosing the degree of HCC differentiation.

Animals↗
PubMed1996

Focal accumulation of iodine-123-BMIPP in liposarcoma of the thigh.

Findings for focal accumulation of 123I-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid ([123I]BMIPP) in a patient with liposarcoma of the thigh are presented. Iodine-123-BMIPP accumulated heterogeneously in the liposarcoma. The region with marked accumulation of [123I]BMIPP was diagnosed as mixoid liposarcoma. The region with little accumulation of [123I]BMIPP was diagnosed as well-differentiated liposarcoma. Differences in the accumulation of [123I]BMIPP may reflect differences in fatty acid metabolism between histopathological types of liposarcoma.

Adult↗