Portal-hepatic venous shunt through a portal aneurysm complicated by hepatic encephalopathy and pulmonary hypertension.

We report a rare case of portal-hepatic venous shunt through an enormous portal aneurysm complicated by pulmonary hypertension. A 66-year-old woman was admitted to our hospital for hepatic encephalopathy. Chest roentgenography revealed pulmonary hypertension. Computed tomography and ultrasound examination demonstrated a shunt between the portal and hepatic veins through an enormous portal aneurysm. The diagnoses of portal-hepatic venous shunt and pulmonary hypertension were confirmed by hepatic venous catheterization and cardiac catheterization. Pulmonary hypertension might result from the effects of vasoconstrictive agents, which should be metabolized by the liver in normal subjects, passing through the intrahepatic shunt into the lung.

Identification of ATP-sensitive potassium channel in frog ventricular myocytes.

ATP-sensitive potassium channels were found in frog ventricular myocytes using the inside-out patch-clamp technique. The channel was selectively permeable to K+. Single-channel conductance was 32.6 pS at 3.0 mM of [K+]o and 132 mM [K+]i and 77.3 pS at 114 mM [K+]o and 132 mM [K+]i. ATP did not affect single-channel conductance. The open probability of the channel was decreased by intracellular application of ATP in both the presence and absence of 2 mM MgCl2. The coexistence of Mg2+ with ATP shifts the dose-response curve for the open probability of ATP-sensitive K+ channel against ATP rightward. The shift of the curve indicates that Mg-ATP is less effective than free ATP in inhibiting the channel. An open-time histogram was fitted by a single exponential function with a time constant of 1.63 +/- 0.17 msec (n = 5) in an ATP-free medium. Mean open time (1.57 +/- 0.10 msec; n = 5) was not altered but the inter-burst time (closed time between bursts) lengthened in 10 microM ATP.

Effect of N-feruloyl tyramine (an analogue of tyramine) on inwardly rectifying potassium channel in frog ventricular myocytes.

Electrophysiological effects of N-feruloyl tyramine (NFT), an analogue of tyramine, on potassium currents in frog ventricular myocytes were examined using single-channel recording and whole-cell voltage clamp technique. Extracellular application of NFT induced a concentration-dependent decrease of macroscopic inward rectifier potassium current (iK1) with ID50 of 198 microM, while tyramine (100 microM) was ineffective in producing an inhibitory effect on iK1. NFT reduced the mean open time of iK1 to 1.3 ms from 3.1 ms in control without affecting the amplitude of single-channel conductance. It is indicated that boi containing NFT produces a prolongation of the plateau phase caused by the suppression of inwardly rectifying K channel. Thus, this prolongation may induce an increase in the inflow of Ca ions, which in turn leads to a positive inotropic effect.

Intracellular signal transduction systems do not regulate Na channel in frog ventricular cells.

The regulation of sodium channel activity through intracellular signal transduction systems was studied on isolated frog ventricular cells using a whole cell patch-clamp technique. Special care was exercised in evaluating the stability of the voltage-clamp condition by observing shifts in the steady-state inactivation curve (h infinity curve) and changes in series resistance. We applied the following reagents: isoproterenol (Iso; 0.1-10 microM) and forskolin (Fsk; 0.1-10 microM) to activate protein kinase A. 1-Oleoyl-2-acetyl-sn-glycerol (40 microM) and 12-O-tetradecanoylphorbol-13-acetate (80-800 nM) were used to activate protein kinase C, and phenylephrine (0.1-10 microM), dopamine (0.1-10 microM), and histamine (10 microM) were used to stimulate alpha-adrenergic, dopaminergic, and histaminergic receptors, respectively. The current-voltage relationship and the h infinity curve for the sodium channel remained unchanged regardless of the application of these reagents. Iso and Fsk did not affect the sodium current but substantially increased the calcium current, suggesting that the intracellular signal transduction systems remained intact. Therefore, it is concluded that sodium channel in frog ventricular cells is not regulated by intracellular signal transduction systems.

Polymorphic ventricular tachycardia with cardiac sarcoidosis: treatment with low-dose metoprolol and cibenzoline.

A 38-year-old female had felt exertional dyspnea for six months. Physical examination and laboratory data including angiotensin-converting enzyme, failed to diagnose sarcoidosis. Her chest X-ray showed cardiomegaly but no hilar lymph node enlargement. Holter ECG showed nonsustained and sustained ventricular tachycardias, monomorphic or polymorphic tachycardia. Echocardiography and contrast left ventriculography showed left ventricular dilatation and generalized hypo- and akinesis. Endomyocardial biopsy revealed myocardial sarcoidosis. Administration of corticosteroids, metoprolol of 20 mg/day and cibenzoline of 300 mg/day was markedly effective for the treatment of ventricular tachycardia. This patient is alive for one year after treatment and the combination therapy seems to contribute to good prognosis.

Renal artery aneurysm: the significance of abdominal bruit and use of color Doppler.

A case of renal artery aneurysm is presented. The patient had no hypertension and no signs of arteriosclerosis obliterans or aortitis syndrome, except for abdominal bruit. A saccular aneurysm, 1 cm in diameter, was demonstrated by two-dimensional and color Doppler ultrasound and documented by angiography. The aneurysm was embolized by a steel coil. The abdominal bruit, though uncommon, is a very important bed-side sign of renal artery aneurysm, if the patient exhibits no arteriosclerosis obliterans or aortitis syndrome. Ultrasound Doppler is very useful in screening for aneurysm.