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Biomedical subjects

H Kawamitsu

Publications and source records attributed to H Kawamitsu.

24 records · Page 2Linked to original sources
PubMed1980

A novel method for purification of poly(ADP-ribose).

A novel method for the purification of poly(ADP-ribose) was established. Calf thymus nuclei were incubated with NAD. After pronase digestion, DNA was isolated as a flocculent form by adding 1 M NaCl and 2 volumes of ethanol. Acid-insoluble poly(ADP-ribose), which was synthesized during incubation, was quantitatively recovered in this DNA fraction. Poly(ADP-ribose) was purified as a single peak from a hydroxylapatite column after the nuclease treatment. Preparation of poly(ADP-ribose) thus obtained revealed the characteristics of pure poly(ADP-ribose), including a ratio of A280 to A260 of 0.24.

Animals↗
PubMedDate not supplied

Two-dimensional time-of-flight MR venography: assessment with detection of chronic deep venous thrombosis in combination with magnetization transfer contrast.

PURPOSE: The purpose of this study was to determine the optimum imaging parameters for 2D-TOF MR venography (MRV) of the pelvis and suprapopliteal deep venous system in combination with off-resonance magnetization transfer constant (MTC) and to evaluate the use of MRV in patients suspected of having chronic deep venous thrombosis (DVT) by comparing its accuracy with that of conventional venography (CV). METHOD: MRV was performed in 10 normal subjects to determine the optimum imaging parameters. Systematically varied scan parameters included flip angles ranging from 30 to 120 degrees by 10 degrees increments. Best TR was calculated by using the theoretical relation between the optimal TR and flow velocity. We then evaluated the use of MRV in 26 patients (total 52 deep venous systems) suspected of having chronic DVT by comparing its accuracy in evaluating the intrapelvic and suprapopliteal deep venous system with that of CV. RESULTS: The optimal imaging parameters for intrapelvic and suprapopliteal venous system MRV were found to be a flip angle of 60 degrees and a pulse sequence of 35/6.9 (TR ms/TE ms) combined with an off-resonance MTC technique. All the main veins of the intrapelvic and suprapopliteal venous systems were clearly demonstrated in each subject. The sensitivity of MRV was 100% and its specificity was 100% for diagnosis of pelvic venous stenosis. The collateral vessels were demonstrated with MRV in all patients. CONCLUSION: 2D-TOF off-resonance MTC MRV of the pelvis and the suprapopliteal lower extremities is suitable for evaluation of intrapelvic branches and suprapopliteal deep venous system and chronic DVT.

Chronic Disease↗
PubMedDate not supplied

Detection of minute pleural fluid in the pleural retracted space associated with peripheral lung cancer: evaluation with MR imaging.

PURPOSE: To evaluate the efficacy of magnetic resonance imaging (MRI) in detecting minute pleural fluid in the pleural retracted space (PRS) associated with peripheral lung cancer. MATERIALS AND METHODS: Our subjects were 20 patients with peripheral lung cancer in whom thin-section CT in the lung window setting demonstrated lesions adjacent to the pleural surface, and who were referred for MR imaging. The imaging findings were retrospectively evaluated and correlated with the histopathologic specimens. Pleural fluid was aspirated for cytology under ultrasound (US) guidance in six patients. RESULTS: STIR MR images revealed water SI areas beneath the chest wall associated with the lung cancer, whereas, on CT images, lung cancer and minute pleural fluid in the PRS showed similar soft-tissue density without enabling easy differentiation. Two of the six patients who underwent aspiration cytology showed malignancy. All histopathologic specimens obtained from 18 patients who underwent surgery showed pleural retraction corresponding to the water SI areas on STIR images. Histopathological study revealed that the fibrotic focus of the tumor tended to occur more intensively when the shape of pleural retraction was thinner and deeper. CONCLUSION: Water SI areas on STIR images were thought to suggest pleural fluid retention in the PRS. MRI was sensitive in detecting minute pleural fluid in the PRS and may help to avoid overdiagnosis of chest wall invasion induced from peripheral lung cancers.

Adult↗
PubMedDate not supplied

Diagnosis of chest wall invasion by lung cancer: useful criteria for exclusion of the possibility of chest wall invasion with MR imaging.

PURPOSE: To compare the accuracy of thin-section CT, conventional static MR imaging (conventional MRI), and breathing dynamic echo planar magnetic resonance imaging (BDEPI) in evaluating lung cancer invasion to the chest wall. MATERIALS AND METHODS: Thin-section CT, conventional MRI, and BDEPI were performed preoperatively in 20 patients suspected of having primary lung cancers adjacent to the chest wall on conventional CT. The results of imaging findings were compared with those of surgical and histopathological findings. RESULTS: All patients were confirmed to have no chest wall invasion after surgery. By thin-section CT, 10 of 20 patients were correctly diagnosed as having no chest wall invasion (50% specificity). Two of the 20 patients were incorrectly diagnosed as having chest wall invasion by conventional MRI and BDEPI (90% specificity). CONCLUSION: When chest wall invasion is suspected on CT scans, static and breathing dynamic MRI are recommended to avoid false positive interpretations.

Adenocarcinoma↗