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An 1 year and 4 months ill infant with vascular ring and VSD is presented. She had serious pulmonary hypertension and dysphagia because of vascular ring consisting of right aortic arch with left ligamentum arteriosum. Division of the ligamentum arteriosum and simultaneous patch closure of large VSD were performed successfully. Postoperative course was uneventful and she recovered from her body weight favorably.

A 3-year-old female with discrete subaortic stenosis is presented. Angiocardiographic studies showed a long segmental narrowing below the aortic valve. Although membranectomy and myectomy were selected as a surgical treatment, a longitudinal aortotomy was performed in order to extend the operation to ventriculoseptoplasty. During the operation, the right coronary cusp was seriously damaged and therefore aortoventriculoplasty was applied. The aortic valve was replaced with a 21 mm St. Jude Medical mechanical prosthesis. The left ventricular outflow tract was adequately enlarged, and postoperative course was uneventful.

Actin-modulating activity was analysed with the 16,131-dalton calcium-binding light chain (CaLc, Kobayashi et al. (1988) J. Biol. Chem. 263, 305-313) of Physarum myosin, which is under an inhibitory Ca-control (Kohama and Kendrick-Jones (1986) J. Biochem. 99, 1433-1446). When skeletal muscle actin was polymerized in the presence of CaLc and Ca2+, increases in both viscosity and birefringence were reduced under high shear conditions. However, CaLc did not inhibit actin polymerization under no or low shearing forces, which was demonstrated by a variety of methods including fluorescence intensity measurements using pyrenyl actin. We propose that actin polymerized in the presence of CaLc and Ca2+ is easily fragmented under high shearing forces to produce the changes in viscosity and birefringence.

The rate of actin polymerization gradually decreased without changing the final level of polymerization, when incubated in the presence of 0.2 mM ATP at pH 8.0 and 25 degrees C. This change was much faster in Mg2+-actin than Ca2+-actin, and Mg2+-actin became denatured and unpolymerizable on prolonged incubation. The drop in the polymerization rate was due both to weakened nucleation and a slowed elongation rate in the incubated actin. The change in the polymerization rate was partially reversible by storing the sample at 0 degrees C. When the rate of polymerization dropped markedly on prolonged incubation, a gel filtration profile showed that Ca2+-actin existed as monomer not as oligomer. On the other hand, Mg2+-actin formed dimers, and other oligomers, as revealed by crosslinking analysis. There were changes in fluorescence intensities due to tyrosine and/or tryptophan residues of the actin molecule, and in difference absorption spectra, suggesting that conformational changes intermediate between native and denatured states occurred during incubation.

A 44-year-old woman suddenly developed dyspnea and loss of consciousness four days after cholecystectomy. Under the diagnosis of acute pulmonary embolism, the patient was treated with anticoagulant with temporary relief of her symptoms. But emergency embolectomy was performed because of large right ventricular thrombus detected by two-dimensional echocardiography. Many reports suggest a relationship between pulmonary embolism and right-sided cardiac thrombi. We consider that two-dimensional echocardiography is essential in case of acute pulmonary embolism.

Phalloidin (2 mol per mol actin)-treated pyrenyl F-actin showed a critical concentration of 1.8 microM in the presence of 10 mM KCl, 0.2 mM ADP, and 5 mM Tris-HCl buffer, pH 8.0 at 25 degrees C. The filament weight concentration did not change at all during and after sonication, yet degrees of flow birefringence increased and the filament number concentration decreased after the termination of sonication. The latter changes were not affected by EDTA, but inhibited by beta-actinin. These observations suggest that reannealing of short pieces of phalloidin-treated actin filaments fragmented during sonication takes place during recovery after sonication.

A management of surgery for infant having a small left ventricular cavity associated with atrial septal defect and tricuspid valve regurgitation was presented. A right upper part of the defect was remained in open during a patch closure of ASD and this portion was temporarily sutured by prolene stayed extracardialy through Waterston's groove. During 20 minutes after weaning from the cardiopulmonary bypass, left heart failure did not appear and then it was completely closed. DeVega's method was employed for the tricuspid valve regurgitation using a absorbale Polydioxanone suture, because of a growth of the sutured annulus. Postoperative course was uneventful and trivial tricuspid valve regurgitation was recognized in angiocardiographic studies performed in 2 weeks and 6 months after operation.

We present a 63-year old man with the arteriovenous fistula caused by the rupture of the aneurysm which extended from the abdominal aorta to the bilateral internal iliac arteries. The clinical manifestations included edema of the left lower extremity, pulmonary embolism, high-output congestive heart failure, origulia, azotemia, liver dysfunction and unstable angina. Because of the variety of the clinical symptoms and the lack of the awareness of this rare complication (arteriovenous fistula), we missed the prompt detection of the entity of the abdominal arteriovenous fistula. We finally succeeded the surgical closure of the fistula and the aortic reconstruction with a woven Dacron bifarcation graft. Problems of diagnosis and operative management are discussed.

It was shown that substoichiometric concentrations of chaetoglobosin J, one of the fungal metabolites belonging to cytochalasins, inhibited the elongation at the barbed end of an actin filament. Stoichiometric concentrations of chaetoglobosin J decreased both the rate and the extent of actin polymerization in the presence of 75 mM KCl, 0.2 mM ATP and 10 mM Tris-HCl buffer at pH 8.0 and 25 degrees C. In contrast, stoichiometric concentrations of cytochalasin D accelerated actin polymerization. Chaetoglobosin J slowly depolymerized F-actin to G-actin until an equilibrium was reached. Analyses by a number of different methods showed the increase of monomer concentration at equilibrium to depend on chaetoglobosin J concentrations. F-actin under the influence of stoichiometric concentrations of chaetoglobosin J only slightly activated the Mg2+-enhanced ATPase activity of myosin at low ionic strength. It is suggested that when the structure of the chaetoglobosin-affected actin filaments is modified, the equilibrium is shifted to the monomer side, and the interaction with myosin is weakened.

A patient who developed subaortic stenosis ten years after patch closure of perimembranous VSD was surgically treated. The subaortic obstruction could not relief sufficiently by the conventional transaortic maneuver. In this surgery, additional ventriculo-septoplasty (modified Konno's operation or Cooley's operation) was performed, preserving the patient's own aortic valve, because of the valve and the valvular ring diameter were almost normal. The postoperative course was uneventful. In this case, a posterior deviation of the infundibular septum and the ventricular septal patch seemed to have played an important role in the pathogenesis of the development of subaortic stenosis.

beta-Actinin is an actin-pointed end capping protein in skeletal muscle. Casella et al. have reported that a protein isolated from muscle acetone powder by procedures similar to those used for beta-actinin purification caps the barbed end of an actin filament (J. Biol. Chem. 261, 10915-10921 (1986)). We have confirmed the above results. However, it turned out that the two proteins were identical as to subunit sizes, peptide maps, and cross-reactivities with anti-beta-actinin IgG. The binding of the two proteins to opposite ends of an actin filament remains unexplained.