Hironori Tenpaku

Silicone-coated polypropylene hollow-fiber oxygenator : Experimental evaluation and preliminary clinical use

BACKGROUND A membrane oxygenator consisting of a microporous polypropylene hollow fiber with a 0.2-microm ultrathin silicone layer (cyclosiloxane) was developed. Animal experimental and preliminary clinical studies evaluated its reliability in bypass procedures. METHODS Five 24-hour venoarterial bypass periods were conducted on dogs using the oxygenator (group A). In 5 controls, bypass periods were conducted using the same oxygenator without silicone coating (group B). As a preliminary clinical study, 14 patients underwent cardiopulmonary bypass with the silicone-coated oxygenator. RESULTS Eight to 16 hours (mean, 12.2 hours) after initiation of bypass, plasma leakage occurred in all group B animals, but none in group A. The O2 and CO2 transfer rates after 24 hours in group A were significantly higher than at termination of bypass in group B (p < 0.005 and p < 0.03, respectively). Scanning electron microscopy of silicone-coated fibers after 24 hours of bypass revealed no damage to the silicone coating of the polypropylene hollow fibers. In the clinical study, the oxygenator showed good gas transfer, acceptable pressure loss, low hemolysis, and good durability. CONCLUSIONS This oxygenator is more durable and offers greater gas transfer capabilities than the previous generation of oxygenators.

Bronchopulmonary foregut malformation.

Bronchopulmonary foregut malformation (BPFM) is a rare anomaly of accessory pulmonary tissue that usually arises from esophagus or stomach. We present a case of extralobar pulmonary sequestration (ELS) connecting with the esophagus by a cyst, the inner wall of which is lined with squamous epithelium or respiratory epithelium. BPFM is sometimes used to group a number of ventral anomalies of accessory pulmonary tissue. The term currently refers specifically to those lesions composed of sequestrations that retain communication with the gastrointestinal tract. Usually the communication is a well-formed muscular tube lined with stratified squamous or columnar epithelium. The presence of both epithelia in a communication that is a component of the BPFM suggests embryogenesis. We describe an adult with BPFM composed of ELS and a connecting stalk to the esophagus by a foregut cyst that contains both squamous epithelium and respiratory epithelium.

Clinical Experience with the Nikkiso Centrifugal Pump

The Nikkiso HPM-15 is a minimally sized centrifugal pump. Preliminary results regarding clinical use of this pump for cardiopulmonary bypass (CPB) procedures have been reported previously. Recently, we have managed some additional cases using a newly developed controller. This article reports our clinical experiences with the use of this pump. We have managed 23 cases with a Nikkiso centrifugal pump. Twenty-two patients underwent CPB and 1 patient with fulminant viral myocarditis underwent percutaneous cardiopulmonary support (PCPS). With this pump, the circuit was extremely easy to prepare and deaeration was achieved readily. Hemodynamics during CPB and PCPS were stable in all cases. The increase in serum-free hemoglobin levels during CPB with this pump was as low as that seen in preliminary tests. A decrease in the platelet count was observed after the initiation of CPB with this pump; however, platelet counts returned to preoperative values 7 days after surgery. Moreover, urine output during CPB with this pump was as high as that seen in preliminary tests. No abnormalities in renal or liver function occurred during CPB. It appears that this new centrifugal pump is safe and easy to operate, and we conclude that it is useful for CPB and PCPS.

Terminal Warm Blood Cardioplegia Improves Cardiac Function Through Microtubule Repolymerization

BACKGROUND To elucidate the mechanisms responsible for the beneficial effects of terminal warm blood cardioplegia, we studied dynamic change in microtubules induced by cold cardioplegia followed by rewarming. Further, we investigated the relationship between cardiac function and morphologic changes in microtubules caused by hyperkalemic, hypocalcemic warm cardioplegia during initial reperfusion. METHODS In protocol 1 isolated rat hearts were perfused at 37 degrees C with Krebs-Henseleit buffer (KHB). After 3 hours of hypothermic cardiac arrest at 10 degrees C, hearts were reperfused at 37 degrees C with one of two buffers: group C, 60-minute reperfusion with KHB (K+, 5.9 mmol/L; Ca2+, 2.5 mmol/L); and group TC, 10-minute initial reperfusion with modified KHB (K+, 15 mmol/L; Ca2+, 0.25 mmol/L), followed by 50 minutes of reperfusion with KHB. Cardiac function after reperfusion was determined as a percentage of the prearrest value. In protocol 2 hearts were perfused at 37 degrees C with KHB containing colchicine (10(-5) mol/L) for 60 minutes. RESULTS There was spontaneous contractile recovery after 10 minutes of initial reperfusion in hearts from group TC as well as improved cardiac function after 15, 30, and 60 minutes of reperfusion compared with that in group C. Immunohistochemical staining and immunoblot analysis demonstrated microtubule depolymerization during hypothermic cardiac arrest and complete repolymerization after 10 minutes of reperfusion with warm buffers in both groups. Colchicine-induced microtubule depolymerization is associated with deterioration of cardiac function. CONCLUSIONS One mechanism responsible for improved cardiac function mediated by terminal warm blood cardioplegia is the restart of contraction after complete microtubule repolymerization.

Metastasis of Thyroid Cancer to the Sternum after Total Thyroidectomy and Laryngectomy

Metastasis of thyroid cancer to the sternum is rare. Ablation is the therapy of choice for patients with metastasizing differentiated thyroid cancer, while surgical resection is an option for those with resectable bony metastasis. This report describes a case of a 65-year-old woman with a sternal tumor. The patient was treated by partial sternal resection and sternal reconstruction with new material polypropylene/expanded polytetrafluoroethylene (ePTFE) composite. The postoperative course was uneventful, and she was free of recurrence after 1 year of follow-up. We conclude that surgery should be used to manage solid bony metastasis from thyroid papillary carcinoma. Further more, a polypropylene/ePTFE composite may be useful for sternal reconstruction after thoracotomy.