Search PubMed⌕ Search

Biomedical subjects

J Hatazawa

Publications and source records attributed to J Hatazawa.

185 records · Page 11Linked to original sources
PubMedDate not supplied

Tracheobronchial mucociliary clearance and alveolar epithelial permeability measured by PET with 18FDG powder.

Tracheobronchial mucociliary clearance and alveolar permeability were measured with positron emission tomography using a water-soluble dry aerosol, sodium-N-acetyl-neuraminate tagged with 2-deoxy-2-[18F]fluoro-D-glucose (18FDG powder). Five normal volunteers inhaled 1.5-2.0 mCi of FDG powder by a single deep breath. The distribution of radioactivity, measured by scanning during a period of 120 min, showed that the 18FDG powder deposition progressed from the central airways to the peripheral alveolar areas. In the tracheobronchial system the radioactivity decreased to 24% of the initial deposition at 60 min. In the peripheral alveolar area, where absorption into blood or lymphatic flow crossing the epithelial layer represents a unique mechanism of clearance for water-soluble 18FDG powder, alveolar radioactivity decreased slowly to approximately 70% of the initial deposition at 60 min after inhalation. Positron emission tomography using 18FDG powder provides a regional evaluation of both mucociliary transport in the tracheobronchial system and epithelial permeability in the alveolar area.

Absorption↗
PubMedDate not supplied

Influence of arterial partial pressure of carbon dioxide on cerebral MRA in normal volunteers.

OBJECTIVE: Signal intensity of MR angiography (MRA) is influenced by the physiological factors of flowing blood in the vessels. We examined whether MRA can detect a cerebral hemodynamic change induced by reducing or elevating the arterial partial pressure of carbon dioxide (PaCO2). MATERIALS AND METHODS: Cerebral MRA was performed in six normal volunteers, each having three measurements during hyperventilation, normal breathing, and 7% CO2 inhalation. The MRA data were obtained by a 0.5 T wholebody scanner and a time-of-flight technique of three-dimensional GE imaging. In addition to the visual inspection, the signal intensity and the lengths of the middle cerebral artery (MCA) and posterior cerebral artery (PCA) were estimated in relation to PaCO2. RESULTS: The MRA appearances of major cerebral arteries were remarkably different depending on the breathing conditions. There was significant difference in the mean signal intensity (p < 0.01) and the mean length (p < 0.01) of the MCA and PCA between the hyperventilation and normal breathing trials. CONCLUSION: The MRA signal was sensitive to the changes in PaCO2 level of flowing blood. This phenomenon may result from changes in the velocity of blood flow in major cerebral arteries.

Administration, Inhalation↗
PubMedDate not supplied

Effects of smoking on regional cerebral blood flow in neurologically normal subjects.

The chronic effects of smoking on regional cerebral blood flow (CBF), and on serum lipids and lipoprotein levels in neurologically normal subjects, were studied. CBF was studied by the 133-Xenon inhalation method and gray matter flow was calculated following the method of Obrist et al. One hundred and eleven subjects, who had no abnormalities in neurological examinations nor in CT scans, were divided into two groups: smokers (37) and non-smokers (74). Those who had a smoking index (Number of cigarettes/day) X (years of smoking history) greater than 200 were designated as smokers. The mean smoking index of smokers was 760. Sixty-two of the 74 subjects in the non-smoking group had never smoked, and the mean smoking index of non-smokers was 17. In the male, CBF was significantly lower in smokers than in non-smokers (mean CBF, 12.5% lower in smokers, p less than 0.001). Increased reduction of CBF with advancing age was also observed. Compared to non-smokers, CBF in smokers was found to be significantly lower than the expected age matched value. Serum high density lipoprotein cholesterol values in smokers were significantly lower, and total cholesterol levels significantly higher than in non-smokers. We concluded that smoking chronically reduces CBF. Decrease of CBF in smokers was probably due to advanced atherosclerosis which produces vascular narrowing and raised resistance in cerebral blood vessels.

Adult↗
PubMedDate not supplied

Unusual widening of Virchow-Robin spaces: MR appearance.

MR in two patients with unusual widening of the Virchow-Robin spaces showed multiple cystic foci up to 2 cm in diameter along the perforating medullary arteries in the cerebral white matter, mainly in one cerebral hemisphere. These areas were of the same signal intensity as cerebrospinal fluid on all pulse sequences. In one patient, the cystic foci in the white matter were biopsied and histologically confirmed to be large Virchow-Robin spaces.

Aged↗