[Resection of a metastatic left ventricular tumor with an aid of thoracoscopy].

A 61-year-old woman who complained of chest pain and cough was admitted to our hospital. She was diagnosed with multiple metastasis of breast or lung cancer, and a cardiac tumor was detected by echocardiography during chemotherapy. The tumor was located on the papillary muscle near the apex, had a smooth surface, and was well mobile. Emergency operation was performed because the tumor was considered to be a cause of cerebral infarction. Under cardiopulmonary bypass, resection of the tumor was performed by trans-mitral-valve approach. By using a thoracoscope, we could share information and obtain the details of the tumor during the operation. Resection using a trans-mitral-valve approach with an aid of thoracoscopy is considered useful.

Coronary artery aneurysm in a patient with Marfan syndrome.

True aneurysm of the coronary artery in Marfan syndrome is very rare. We present a patient with Marfan syndrome who had aneurysms from the ascending aorta to the thoracoabdominal aorta and a large aneurysm of the left main coronary artery after an original Bentall operation. Prosthetic graft replacement of total aorta, coronary artery bypass grafting, and removal of the aneurysm of the left main coronary artery were successfully performed.

[A case of malignant fibrous histiocytoma of the chest wall].

A case of malignant fibrous histiocytoma of the chest wall. A 56-year old man was admitted to the hospital with a complaint of showing abnormal shadow on chest X-ray. Chest X-ray and chest CT scan showed a calcified tumor of the chest wall. Histological diagnosis could not be made prior to the operation. Wide resection of the right chest wall containing the tumor and partial resection of the right lung were done. Malignant fibrous histiocytoma (MFH) showing a striform-pleomorfic pattern was recognized histologically with resected specimen. MFH commonly arises in the soft tissues of the extremities, but rarely in those of the chest. This paper also presents a review of 38 reported cases of MFH originated from the chest wall.

Regulatory mechanisms of calponin phosphorylation in endothelin-1-induced contraction of porcine coronary artery.

Calponin is an actin-associated protein that appears to play an auxiliary regulatory role in the contraction of smooth muscle. We report here on the mechanisms for regulation of calponin phosphorylation in the endothelin-1-induced contraction of porcine coronary artery. Treatment of strips of porcine artery with endothelin-1 increased calponin phosphorylation and contraction in a concentration-dependent manner. The time course of the phosphorylation was biphasic, with the response to endothelin-1. The extent of phosphorylation reached a maximum within 5 min of stimulation with 10(-7)M endothelin-1 and then it declined rapidly to reach a minimum at 20 min. A potent inhibitor of protein kinase C, GF109203X, inhibited both calponin phosphorylation and contraction that were induced by endothelin-1 at 5 min, without an inhibition for myosin light chain phosphorylation. Protein phosphatase inhibitor, okadaic acid, had no effect on the extent of phosphorylation at 5 min, but it significantly inhibited the subsequent decrease in calponin phosphorylation. In contrast, in PDBu-treated strips of coronary artery, okadaic acid caused a significant steady increase of the extent of calponin phosphorylation. Our results suggest that calponin phosphorylation might be regulated by protein kinase C and okadaic acid sensitive protein phosphatases, in the endothelin-1-induced contraction of porcine coronary artery.

Two distinct actin-binding sites of smooth muscle calponin.

Amino acid residues 145-163 of calponin have been proposed as a putative actin-binding site [Mezgueldi, M., Mendre, C., Calas, B., Kassab, R. & Fattoum, A. (1995) J. Biol. Chem. 270, 8867-8876]. Our previous work demonstrated that a fragment of calponin, which corresponded to the first repeated region of calponin and contained the preferred site of phosphorylation by protein kinase C [Nakamura, F., Mino, T., Yamamoto, J., Naka, M. & Tanaka, T. (1993) J. Biol. Chem. 268, 6194-6201] enhanced the Ca2+-induced contraction of permeabilized smooth muscle [Itoh, T., Suzuki, A., Watanabe, Y., Mino, T., Naka, M. & Tanaka, T. (1995) J. Biol. Chem. 270, 20400-20403]. In the present study, we compared the interactions with actin of a synthetic peptide (Lys172-His187) that encompassed the first repeated region with those of three other synthetic peptides. Lys172-His187 inhibited the binding of calponin to F-actin in a concentration-dependent manner but not the binding of caldesmon. Gly141-Gly160, including the above-mentioned putative actin-binding site, also competed with intact calponin to the same extent as Lys172-His187. Inhibition of actomyosin MgATPase activity was observed only with Gly141-Gly160. Lys172-His187 and other tested peptides had no effect. However, Gly141-Gly160 and Lys172-His187 reduced the fluorescence intensity of pyrene-labeled F-actin with approximately equal potency. Moreover, Lys172-His187 was able to reverse the inhibition of actomyosin MgATPase activity by calponin. Lys172-His187 was phosphorylated stoichiometrically by protein kinase C and phosphorylation of this peptide decreased its actin-binding activity. These observations suggest the direct involvement of two distinct actin-binding sites, with different regulatory functions, in the interactions of calponin with actin.

Phosphorylation of calponin mediated by protein kinase C in association with contraction in porcine coronary artery.

Calponin is an actin-associated regulatory protein in smooth muscle. We report that both endothelin-1 (ET-1) and phorbol 12, 13-dibutyrate (PDBu) caused a significant increase in phosphorylation of calponin during contraction of porcine coronary artery, while high levels of KCl were ineffective. This phosphorylation was predominantly catalyzed by activation of protein kinase C(PKC). In addition, the level of phosphorylation of calponin increased closely in association with the size of the contractile force induced by PDBu. Thus, the phosphorylation of calponin in vivo by PKC might modulate in part the contraction of smooth muscle that occurs in response to ET-1 or PDBu.

Clinical experience using the Bio-pump for extracorporeal circulation during open-heart surgery.

The Bio-pump is still being used in a wide range of clinical applications such as open-heart surgery, left-heart bypass, extracorporeal membrane oxygenation, and supplementary circulation. Clinical application of the Bio-pump for extracorporeal circulation in 21 patients undergoing open-heart surgery was compared with application of the roller pump in terms of their effects on hemolysis, platelet function, and renal function. Although the amount of hemolysis was not significantly different between the Bio-pump group and the roller-pump group, platelet function was slightly better maintained in the Bio-pump group as judged by the levels of platelet factor 4, beta-thromboglobulin, and 6-keto-prostaglandin F1 alpha/thromboxane B2. There was no difference between the two pumps in terms of their effects on renal function. The above findings lead us to conclude that there is a slight advantage to use of the Bio-pump in clinical settings.