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Biomedical subjects

Kazutoshi Kotani

Publications and source records attributed to Kazutoshi Kotani.

6 recordsLinked to original sources

Transintestinal systemic oxygenation using perfluorocarbon.

PURPOSE: Perfluorocarbons have an excellent oxygen- and carbon dioxide-carrying capacity. This prompted us to investigate the feasibility of transintestinal systemic oxygenation using perfluorocarbon. METHODS: A rat hypoventilation model (room air, 20 breaths/min and a tidal volume of 10 ml/kg) was thus established, and FC-77 (Sumitomo-3M, Osaka, Japan) was used as a perfusate. Oxygenated FC-77 was perfused through the small intestine for 4 h. The rats were allocated into three groups as follows. Group 1 (n = 6): hypoventilation only; Group 2 (n = 6): saline was perfused instead of FC-77; Group 3 (n = 6): FC-77 was perfused. Arterial blood samples were drawn from the common iliac artery every 30 min until the end of perfusion. A standard blood gas analysis was performed. RESULTS: The PaO2 level in Group 3 was significantly higher than in Groups 1 or 2 (P = 0.006: at the end of perfusion, Group 1 = 58.6 +/- 14.5 mmHg, Group 2 = 65.2 +/- 29.4 mmHg, Group 3 = 84.0 +/- 35.5 mmHg). The PaCO2 level in Group 3 was significantly lower than that in Groups 1 or 2 (P = 0.014: at the end of perfusion, Group 1 = 56.8 +/- 8.5 mmHg, Group 2 = 52.6 +/- 5.7 mmHg, Group 3 = 44.4 +/- 11.1 mmHg). CONCLUSION: Our findings indicate that transintestinal systemic oxygenation is indeed possible and could therefore become a useful new modality for respiratory assist.

Animals↗

A subacute hypoxic model using a pig.

PURPOSE: A large animal model of hypoxia is necessary to develop a new therapeutic method for respiratory failure. METHODS: The experiments were performed on six pigs weighing from 15 to 19 kg. Under general anesthesia the left chest was opened and the left main bronchus was closed by a stapler. A Swan-Ganz catheter was inserted through the right jugular vein. The right carotid artery was cannulated and the mean arterial blood pressure was monitored, and arterial blood samples were drawn every 24 h until 96 h after the operation. The blood samples were submitted for a blood gas analysis. All data were expressed as the mean +/- standard deviation of the mean. RESULTS: The partial pressure of the oxygen of the arterial blood at baseline (104.8 +/- 24.3 mmHg) significantly decreased at 24 h after closure of the bronchus (76.7 +/- 9.9 mmHg, P < 0.001) and thereafter remained at the same level for 4 days. CONCLUSION: This hypoxic model using a pig was found to be very simple, effective, and reproducible. This model can be used for a variety of experiments to evaluate new therapeutic modalities for respiratory failure.

Animals↗

Transintestinal oxygenation with perfluorocarbon: investigation of perfusion rate.

OBJECTIVE: Perfluorocarbons are structurally similar to hydrocarbons but with the hydrogen atoms replaced by fluorine. In general, perfluorocarbons have an excellent oxygen and carbon dioxide carrying capacity. We studied the suitability of oxygenated perfluorocarbon as an agent for transintestinal oxygenation and measured its perfusion rates under different conditions. SUBJECTS AND METHODS: We used FC-77 (Sumitomo 3M, Tokyo, Japan) perfluorocarbon and a rat hypoventilation model (room air, 20 breaths/min, a tidal volume of 10 ml/kg). Oxygenated FC-77 was perfused through the small intestine for 4 hours. Rats were allocated to 3 experimental groups according to the perfusion rate and a control group: Group 1 (n=6), 10 ml/min; Group 2 (n=6), 2.5 ml/min; Group 3 (n=6), 0.75 ml/min; Group 4 (n=6) served as a control (hypoventilation only). Arterial blood samples were drawn every 30 minutes. Standard blood gas analysis was performed. RESULTS: After four hours of perfusion, the PaO2 levels in Groups 1 to 3 were significantly better than Group 4 (p<0.01, Group 1: 141.7 +/- 18.0 mmHg, Group 2: 145.2 +/- 25.1 mmHg, Group 3: 120.5 +/- 21.2 mmHg, Group 4: 67.4 +/- 7.2 mmHg). PaCO2 levels in Groups 1 and 2 were significantly better than Groups 3 and 4 (p<0.01, Group 1: 42.6 +/- 7.2 mmHg, Group 2: 52.1 +/- 7.7 mmHg, Group 3: 78.2 +/- 22.8 mmHg, Group 4: 75.3 +/- 10.3 mmHg). CONCLUSION: In the present settings, 8 ml/kg/min was adequate for oxygenation and CO2 clearance. This approach promises to become another modality for respiratory assistance.

Animals↗

Mediastinal parathyroid cyst with tracheal constriction.

A 63-year-old man visiting a physician for slight dyspnea, attributed to a lump on his neck, was found in ultrasonography and computed tomography to have a cyst extending from the left lobe of the thyroid gland to the superior mediastinum. Radiography showed right deviation of the trachea. The cyst disappeared after fine-needle aspiration, but cyst fluid subsequently reaccumulated and he was admitted to our hospital. No abnormalities were detected in tests of thyroid and parathyroid function or blood chemical analysis. The cyst was surgically removed and diagnosed as a nonfunctioning parathyroid cyst, based on the high-intact parathyroid hormone in cyst fluid. The patient recovered fully and has shown no recurrence in the 11 months to data since surgery.

Cysts↗