Kenzo Kawakami

Age-related changes in the static and dynamic mechanical properties of mouse lungs.

To investigate the effects of aging on pulmonary mechanical properties in mice, we devised a new experimental apparatus to measure the respiratory impedance of excised lungs in mice and examined age-related changes in both static and dynamic properties. In an accelerated senescence-resistant strain of mice, SAMR1 (Takeda, T., Y. Fukuchi, Y. Uejima, K. Teramoto, T. Oka and H. Orino, J. Am. Geriatr. Soc. 39: 911-919, 1991), ranging from 3 to 24 months of age, static compliance (Cst) as well as total lung capacity increased significantly with age, whereas specific compliance and the K value, as determined by exponential analysis, showed no significant change. In the dynamic study, dynamic compliance (Cdyn) increased significantly with age, whereas the frequency dependence of Cdyn (Cdyn/Cst) did not vary with age. From these results we concluded that lung elasticity, normalized to lung volume, remained constant with age and that the effects of aging on pulmonary mechanics might be solely derived from increases in lung volume in the SAMR1 strain of mice.

Distorted Trachea in Patients with Chronic Obstructive Pulmonary Disease

Background and Objectives: We evaluated the size and configuration of the trachea in patients with chronic obstructive pulmonary disease (COPD; n = 35) on high-resolution computed tomography (HRCT) images and compared them with those of healthy volunteers (n = 24). Methods: Using a newly developed computed method for analyzing the digital data of HRCT, the size and configuration of the trachea were automatically evaluated. Results: The size of the trachea of the COPD subjects was the same as that of the control subjects; however, the configuration was more distorted in the COPD patients. There was no difference in the tracheal index (TI), which is the ratio of the coronal to the sagittal length, between these two groups; however, the ratio of the short to the long radius (SR/LR) was significantly smaller in the COPD group than in the control group. There was a significant correlation between SR/LR and airflow limitation as assessed by pulmonary function tests in the COPD group. Conclusions: The SR/LR is a better index of tracheal deformity than the classical TI. This deformity is not a consequence secondary to hyperinflation or emphysematous change of the lung, because the low attenuation area of the lung was not correlated with SR/LR.

Massive mediastinal bleeding due to spontaneous rupture of the vertebral artery in von Recklinghausen disease

In Von Recklinghausen disease, patients rarely demonstrate vascular abnormalities, but several reports have noted massive bleeding from vascular rupture. A 28-year-old man with Von Recklinghausen disease was admitted to our hospital because of swelling on the left neck accompanied by dyspnea. Neck and thoracic CT revealed a high density shadow on the mediastinum and left upper thorax which was suspected to indicate hemomediastinum. Under suspicion of bleeding from the intrathoracic artery, the patient underwent on surgery. Massive hematoma disrupted visual recognition of bleeding point, but under anatomical consideration, we concluded that the bleeding was from the ruptured left vertebral artery (VA) which branched independently from the aorta. The left VA was ligated distally and proximally. Left subclavian artery, injured unexpectedly, was not reconstructed but sutured carefully because of its fragility. Thus massive bleeding was controlled. Histology of the neighboring subclavian artery revealed involvement with neurofibrinomatosis. Although the patients left arm demonstrated a slightly low blood pressure, he was discharged without complaint on the 56th postoperative day.

N-Isopropyl-p-iodoamphetamine receptors in normal and cancerous tissue of the human lung

N-Isopropyl-p-iodoamphetamine (IMP) receptors in normal human lung tissue were characterized using a radioligand binding assay with iodine-125 IMP as the ligand. Saturation binding studies revealed the presence of two binding sites with dissociation constant (Kd) values of 53 ± 2 and 4687 ± 124 nM and maximum binding capacity (Bmax) values of 7 ± 1 and 133 ± 27 pmol/mg protein (n=5) respectively. The IC50 values of various amines were as follows: IMP, 9 × 10−5M; propranolol, 5 × 10−4M; haloperidol, 6 × 10−4M; ketamine, 9 × 10−3M; dopamine, 1 × 10−2M. The IMP receptors of cancerous tissue obtained from human lung also had two binding sites with Kd values of 54 ± 2 and 5277 ± 652 nM and Bmax values of 7±1 and 103 ± 21 pmol/mg protein (n = 3) respectively. There was no significant difference in binding parameters between normal and cancerous lung tissue. These results demonstrate the existence of IMP receptors and suggest that cancer does not affect the nature of IMP receptors in human lung tissue.

Phase differences between chest and mouth flows in patients suffering from pulmonary disease

The phase difference (PD) between mouth flow and chest flow during rest breathing was measured in pulmonary diseased patients using a body box and the results were compared with normal subjects. Whereas the PD increased in patients with chronic pulmonary obstructive disease (COPD) compared to normal subjects, PD was found to be normal in patients with interstitial pulmonary fibrosis (IPF) (Normal: 2.94 +/- 1.25, COPD: 11.32 +/- 4.17*, IPF: 2.62 +/- 1.67 degrees; *P < 0.01). PD correlated well with FEV1.0/VC%, PFR, RV/TLC, VTG and Ra (r: -0.759, -0.672, -0.788, 0.666, 0.606). From an in-depth analysis of the results, we suggest that the factors which increase PD in COPD patients include hyperinflation of the lung, increases in airway resistance and increases in the parallel inhomogeneity of airway resistance accompanied by an unevenness of alveolar pressures. PD was thought to be clinically useful for the evaluation of the pathological stages of COPD because it reflects the overall clinical manifestations in COPD patients.