Yoshiki Nonami

Two types of major venous anomalies associated with abdominal aneurysmectomy: A report of two cases

We report herein the cases of two patients with major venous anomalies associated with abdominal aneurysmectomy, one being an isolated left-sided vena cava and the other, a retroaortic left renal vein, and discuss the clinical significance of such anomalies. In the first patient, an isolated left-sided vena cava was correctly diagnosed preoperatively by contrast-enhanced computed tomography (CE-CT) and digital subtraction angiography (DSA) which revealed that the vena cava crossed the normal portion of the aorta and the right renal vein ran cephalad. In the second patient, a retroaortic left renal vein was also preoperatively diagnosed with CE-CT and DSA. In both patients, dissection was performed, taking care to avoid injury to anomalous venous tributaries, and graft replacement for abdominal aneurysm was successfully carried out. Thus, careful preoperative evaluations using such imaging techniques as CE-CT, DSA, and venographic studies, are important for establishing the presence of an associated venous anomaly preoperatively to ensure the success of abdominal aneurysmal surgery.

Optimal flow rates for integrated cardioplegia

BACKGROUND Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min). METHODS Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29 degrees C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow. RESULTS Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow groups. CONCLUSIONS Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery.

Quenching the Effects of L-Arginine on Free Radical Injury in Cultured Cardiomyocytes

Neutrophil activation and oxygen-derived free radical formation have been implicated in cardiac ischemiareperfusion injury. To elucidate the mechanism of ischemiareperfusion injury, we thus determined the effect of the nitric oxide (NO) precursorl-arginine on the free radical injury of cultured cardiomyocytes which were obtained from patients undergoing corrective surgery for tetralogy of Fallot. Free radicals were generated from hypoxanthine via xanthine oxidase, and the cellular changes were determined microscopically.All concentrations of L-arginine (0.5 to 3 mM) prolonged the myocyte survival time compared to the control group, with 0.5 mMl-arginine increasing the survival time to the greatest extent. Cellular susceptibility to free radical injury was the lowest with 0.5 mMl-arginine. Further experiments were performed with 0.5 mMl-arginine plus 100 mM or 1 000 mM of the NO synthase (NOS) inhibitorNG-nitro-l-arginine methylester (l-NAME) to determine whether or not the effects of L-arginine are mediated through the NO pathway. The survival time for the cells treated with a concentration ofl-NAME was shorter than for the cells treated with 0.5 mMl-arginine alone. These results suggest thatl-arginine acts through the NO-dependent pathway. In conclusion, our findings thus confirmed the quenching effects of NO on free radical injury in cultured cardiomyocytes.

The role of nitric oxide in cardiac surgery.

The release of nitric oxide (NO) from coronary endothelial cells is impaired following reperfusion; however, several experimental studies have found that it exerts a cardioprotective effect during myocardial ischemiareperfusion. Thus, attempts have been made to supplement NO production exogenously during reperfusion when endogenous NO release may be diminished. Conversely, other studies suggest that NO exacerbates reperfusion injury by inducing the production of peroxynitrite. NO has also been reported to provide beneficial effects as a selective pulmonary vasodilator to relieve pulmonary hypertension. A loss of NO-mediated relaxation caused by the dysfunction of endothelial cells is characteristic of intimal hyperplasia, and nitrosovasodilators have proven efficient against atherosclerotic coronary heart disease, which may be attributable to their antiplatelet effects as well as to vasodilation. Furthermore, protamine sulfate, which is rich inl-arginine, is thought to augment NO production by supplying exogenousl-arginine, or to act on endothelial cell receptors to stimulate the production of NO. This review summarizes the current role of NO in cardiac surgery.

A case of salivary gland-type mixed tumor of the lung differentiating toward type II alveolar epithelial cells in glandular components with a literature review

Abstract. Salivary gland-type mixed tumor primarily arising in the lung is extremely rare. We report here a case of this type of tumor that occurred in the periphery of S4 of the right middle lobe in a 74-year-old man. Light-microscopically, this lung tumor, 15×9mm in size, exhibited almost the same features as those of mixed tumor of the salivary gland intermingled with chondromyxoid stroma, glandular component, solid growth pattern of myoepithelial components and well-developed cartilage formation, exhibiting a sharp margin. Immunohistochemical study revealed that the glandular components in the tumor was positive for thyroid transcription factor-1, TTF-1, a marker of epithelial cells of the thyroid as well as the lung. Furthermore, surface lining cells of the glandular components and luminal contents were positive for surfactant apoprotein A, PE-10, used as a marker of type II alveolar epithelial cells. These findings clearly demonstrate for the first time that glandular epithelial cells in the present salivary gland-type mixed tumor exhibited differentiation toward type II alveolar epithelial cells.