Separation of current- and voltage-dependent inactivation of calcium current in frog sensory neuron

The inactivation process of the calcium current was studied in frog dorsal root ganglion cells using a newly developed 'concentration clamp' technique, and an inactivation component independent of Ca influx was separated from the Ca-dependent component. The neuron was first placed in Ca-free solution, and pre-pulses of various amplitude were applied, thereby inducing depolarization without the Ca influx. Successive test pulses were applied immediately after a rapid exchange to a solution containing normal Ca. The amount of inactivation under this condition was much smaller than that measured when both pre- and test pulses were applied in the normal solution, and reached a steady level on pre-pulses over +50 mV. We suggest that the inactivation process of the Ca current consists of two components, i.e. a dominant component which is dependent on Ca influx, and a smaller one which is presumably voltage-dependent.     

Angioscopic prediction of late vascular patency after transluminal balloon angioplasty for arteriosclerotic obstructions of the artery of the lower extremities]

Arterial occlusion or stenosis of the lower extremity due to arteriosclerosis obliterans (ASO) was treated by transluminal balloon angioplasty (TBA). Angioscopic observation of the vascular lumen, performed immediately after TBA, provided five major findings: (1) abrasion of the intima, (2) irregularity of the lumen due to poor expansion, (3) laceration of the wall, (4) mural thrombus and (5) calcification. The degree of each of these abnormalities was scored with a 3-grade scale (0, 1 and 2), and scores for the 5 abnormalities were totaled in each patient. Analysis of the relationship between scores and postoperative vascular patency demonstrated that patients without vascular patency in the early (within 6 months) or late period (6 months or more) after the operation had higher total scores as compared to those in whom the vessel remained patient in the corresponding postoperative periods (p less than 0.01, p less than 0.05). Among others, patients with a total score over 5 showed markedly lower patency rates in the early period (10%) as well as late period (0%) after the operation (p less than 0.01). These results indicate the usefulness of post-TBA angioscopic observation of vascular lumen in predicting the long-term patency of the vessels operated on.     

A clinicopathological studies on gastrointestinal leiomyosarcomas, with special reference to prognosis

Twenty-five cases of gastrointestinal leiomyosarcomas were subjected to clinico-pathological studies in an attempt to correlate the prognosis with tumor size, mitosis, cellularity and DNA ploidy pattern. Leiomyosarcomas greater than 5cm in diameter had poorer prognosis. Those with mitotic index larger than 3.0/mm2, cellularity larger than 3.0/0.0004mm2, DNA aneuploidy had poorer prognosis. By multiple regression analysis, mitotic index was useful for the prediction of tumor recurrence in earlier postoperative period, but cellularity, tumor size were useful for the prediction of recurrence in later postoperative period. As for the type of tumor recurrence, hematogenous metastasis was observed in 7 cases, peritoneal dissemination in 2 and local recurrence in 4. Four cases with local recurrence had all hematogenous metastasis. Two cases of gastric leiomyosarcomas developing local recurrence were greater than 10cm in diameter and gastric local resection was done for them. One case was diagnosed benign leiomyoma in the rectum histologically, but after trans-anal tumor resection local recurrence and metastasis to the lung occurred. We must pay attention to the surgical margin and the surface of tumor dissection during of the tumor, especially in larger tumors. Aggressive surgical resection is efficient for the treatment of recurrent tumors.