The figure-L unilateral mini-sternotomy for anterior mediastinal tumor.

We performed a figure-L unilateral mini-sternotomy for anterior mediastinal tumor resection in ten patients. Pathological diagnosis among the ten included six thymomas, three mature teratomas including one with a seminoma component, and one thymic cyst. Mean tumor length was 7 x 5 x 4 cm. The required skin incision was 8 cm in mean length. The third intercostal space was transected in six cases, the fourth intercostal space in four cases. Bilateral internal thoracic arteries were preserved in all cases. All tumors were completely resected without complications during the procedure. Mean operating time was 106 minutes (range 85 to 120 minutes). Postoperative hospital stay ranged from three to seven days without any complications. All patients were alive at the end of a mean follow-up period of 39 months (range 3 to 60 months). The figure-L unilateral mini-sternotomy is considered an effective and useful minimally invasive approach for anterior mediastinal tumors.

Placement of the Dumon stent using a flexible bronchofiberscope via tracheostomy.

In this paper, we report on a new technique of Dumon stent placement using a flexible bronchofiberscope. This procedure was used to insert Dumon stents in two bronchial obstruction and two bronchofistula cases. The stenting technique described here can be used through either a tracheostoma or the oral cavity; it presents a very straightforward and safe procedure that does not require the use of a rigid bronchoscope.

A single-stage video-assisted thoracoscopic surgery procedure for simultaneous bilateral spontaneous pneumothorax in a supine position.

We report on the case of a 23-year-old man with simultaneous bilateral spontaneous pneumothorax (SBSP), treated with bilateral video-assisted thoracoscopic surgery (VATS) in a supine position. SBSP is a very rare condition that can be life-threatening when therapeutic techniques fail. We performed a unique operative procedure for SBSP using one-stage bilateral VATS in a supine position. This procedure is less invasive, more effective, and safer for the treatment of SBSP.

Clinical experience with temporary vena cava filters.

An experience with temporary filter placement, which seems to be safe and effective for temporarily preventing pulmonary embolism, is reported. Since October 1997, six patients had temporary filters. There were two men and four women, with a mean age of 37 years. Three filters were placed at the infrarenal inferior vena cava, two at the suprarenal inferior vena cava, and one at the superior vena cava. All filters were placed before various surgical interventions. During filter placement, anticoagulation therapy was routinely performed. There were no complications at and during filter placement. No pulmonary emboli occurred during surgical intervention. All filters were successfully removed, two of which were exchanged for permanent filters. All patients are alive and well without recurrent deep vein thrombosis and/or pulmonary emboli during a follow-up period of 11 to 25 months. Although this experience is small, temporary filter placement is safe and effective for short-term prevention of pulmonary emboli even in older patients or those with malignant disease. Veins of the upper part of the body may be more favorable than the femoral vein for insertion of a temporary filter. Temporary filters can be safely placed not only at the infrarenal inferior vena cava, but also at the suprarenal inferior vena cava or superior vena cava.

Persistent Na+ current and Ca2+ current boost graded depolarization of rat retinal amacrine cells in culture.

Retinal amacrine cells are depolarized by the excitatory synaptic input from bipolar cells. When a graded depolarization exceeds the threshold level, trains of action potentials are generated. There have been several reports that both spikes and graded depolarization are sensitive to tetrodotoxin (TTX). In the present study, we investigated the contribution of voltage-gated currents to membrane depolarization by using rat GABAergic amacrine cells in culture recorded by the patch-clamp method. Injection of a negative current induced membrane hyperpolarization, the waveform of which can be well fitted by a single exponential function. Injection of positive current depolarized the cell, and the depolarization exceeded the amplitude expected from the passive properties of the membrane. The boosted depolarization sustained after the current was turned off. Either 1 microM TTX or 2 mM Co2+ suppressed the boosted depolarization, and co-application of TTX and Co2+ blocked it completely. Under the voltage clamp, we identified a transient Na+ current (fast I(Na)), a TTX-sensitive persistent current that reversed the polarity near the equilibrium potential of Na+ (I(NaP)), and three types of Ca2+ currents (I(Ca)), L, N, and the pharmacological agent-resistant type (R type). These findings suggest that the I(NaP) and I(Ca) of amacrine cells boost depolarization evoked by the excitatory synaptic input, and they may aid the spread of electrical signals among dendritic arbors of amacrine cells.

Targeting adjuvant brachytherapy for a superior sulcus tumor: report of two cases.

We report herein the cases of two patients who underwent complete resection of a superior sulcus tumor (SST) plus adjuvant brachytherapy, with the area to be irradiated determined by a computer program system designed to minimize unnecessary irradiation to the normal components and to optimize the effect on the targeted area. Although the efficacy of brachytherapy on the inhibition of local relapse needs to be observed over a long period, the selective and alternative use of delivering adjuvant brachytherapy by this method appears to enhance the quality of life of patients with a SST.

Continuous growth of autocatalytic sets.

We investigated a topology of the reaction network for polymerization of amino acids as the emergence and the continuous growth of autocatalytic sets. Reaction networks including transpeptidation reaction can yield newer and longer peptides with time having higher concentrations. Conditions necessary for the occurrence of transpeptidation can be met in actual amino acid/peptide systems.

L-type calcium channels in the axon terminal of mouse bipolar cells.

Two types of calcium current (I(Ca)) have been identified in the bipolar cell of the mouse retina: a transient (T-) type current and a long lasting (L-) type current. It has been suggested that the former is present in the soma and the latter in the axon terminal. To establish the cellular localization of the two types of I(Ca), bipolar cells of the mouse retina was studied electrophysiologically in a slice preparation, and immunocytochemically by staining specific calcium channels in isolated cells. The dihydropyridine-sensitive L-type I(Ca) was recorded in the axon terminal, and the T-type current was recorded in the somatic region. Strong immunoreactivity to a polyclonal antibody against the L-type calcium channel was found in the axon terminal. These observations suggest that the L-type I(Ca) is generated at the axon terminal and contributes to the transmission of sustained depolarization.

Two types of stretch-activated channels coexist in the rabbit corneal epithelial cell.

Ion channels contribute to the regulation of cellular function through control of the membrane potential and intracellular concentration of various ions. We examined stretch-activated channels in the corneal epithelial cell. Patch clamping was applied to enzymatically dissociated corneal epithelial cells to characterize their stretch-activated ion channels. The plasma membrane was stretched by applying suction to the patch pipette in cell-attached or inside-out patch configuration. The ion selectivity, voltage-dependence, and stretch-dependence were examined. Two kinds of stretch-activated channel events were observed; the previously-reported large conductance (L) channel and a novel small conductance (S) channel. The probability of recording L vs. S channels in the cell-attached configuration was about 2:1. The L channel was potassium selective with single channel conductance (gamma) of about 160 pS under the symmetrical (150 mm K+) solution. The S channel was permeable to Na+ and K+ with gamma of about 20 pS under the same conditions. Both L and S channels showed little activity in the absence of suction applied to the recording pipette. Channel activity was evoked by suction (negative pressure) stronger than -20 mmHg in both channels. The open probability (Po) and the mean current increased in proportion to further applied stretch and did not saturate for applied suction as strong as -80 mmHg, the pressure at which the gigaseal started to break. Thus, two types of stretch-activated channels coexist in corneal epithelial cells; a potassium-selective L channel and non-selective S channel. The contribution of these channels to the membrane potential is discussed.

[Application of heparin-coated percutaneous cardiopulmonary support system to elective cardiac and aortic operations].

Non emergency use of heparin-coated percutaneous cardiopulmonary support (PCPS) in cardiovascular surgery was applied in 4 patients (3 patients with descending aortic aneurysm, and one with aortic valvular stenosis and impaired left ventricular contractility (LVEF = 0.18). In aortic surgery, femoral inflow and outflow cannulae were inserted after introduction of anesthesia, and low flow F F bypass was established with the patient in supine position. Subsequently lateral posture was taken for aortic grafting. Activated clotting time was kept around 200 sec during the whole operative period and F F bypass was continued after the grafting procedure, and the cannulae were removed when the patient posture was returned to supine. With this method cannulation and decannulation were easy, and almost prone position, which was sometimes necessary for dissection of the adhesion of lung to the posterior aspect of the aneurysmal wall, was easily performed. Because of the percutaneous insertion, there was no local hemorrhage in the groin. Heparin coating circuit permitted only low grade systemic anticoagulation during the operative period, which could lead to decreased amount of hemorrhage. Long F F bypass without full heparinization made no harmful effect on patients' coagulability nor their hemodynamic status. For the patient with extremely impaired cardiac contractility, "scheduled PCPS and IABP" was proved to be safe, reliable, and cost-effective: F F bypass was established before sternotomy, and intracardiac procedure with aortic crossclamping was performed under total cardiopulmonary bypass using PCPS. After declamping of the aorta, weaning from the bypass was not tried and total anticoagulation was reversed with protamine. Then the sternum was closed and patient was transferred to ICU with the PCPS and IABP on. After more than 10 hours, when the cardiac contractility recovered from the intraoperative ischemic insult to a considerable degree, weaning from PCPS was successfully accomplished.

Release of secretin by licorice extract in dogs.

To determine the effect of a fraction of licorice extract, FM100, on the endogenous release of secretin and exocrine pancreatic secretion, five dogs were prepared with chronic pancreatic fistulas and gastric cannulas. Intraduodenal administration of licorice extract (pH 7.4) in three different doses (0.5, 1.0, and 2.0 g) resulted in significant increases of both plasma secretin concentrations and pancreatic bicarbonate secretion in a dose-related manner. The plasma secretin concentration and pancreatic bicarbonate output produced by licorice extract correlated well. Intragastric administration of licorice extract (2 g) in 5% liver extract meal (in which pH was maintained at 5.5 by the intragastric titration method) resulted in significant increases of both plasma secretin concentration and pancreatic bicarbonate output. The increase in pancreatic bicarbonate secretion was completely abolished by intravenous infusion of a rabbit antisecretin serum in the two dogs so studied. Thus, the present study indicates that the endogenous release of secretion is involved in a mechanism of an increase in exocrine pancreatic secretin induced by FM100.