Heart metastases from gastric sarcoma. A case report.

Cardiac involvement by metastatic gastric sarcoma is a rare event. We describe an unusual case of gastric sarcoma involving the heart in a 29-year-old man who presented with heart failure. The diagnosis was made at two-dimensional echocardiography. Heart metastases prolapsing into and obstructing the mitral valve orifice were located in the left atrium. In an attempt to excise the left atrial mass, the patient underwent heart surgery twice. The resections were non-curative. The patient died of refractory heart failure 9 months after the onset of symptoms. This case report is an example of a secondary intracavitary tumor that causes obstruction of the mitral valve orifice. Two-dimensional echocardiography has been confirmed as the examination of choice for the early diagnosis of cardiac tumors.

Plasma Membrane H+-ATPase in Maize Roots Induced for NO3- Uptake.

Plasma membrane H+-ATPase was studied in maize (Zea mays L.) roots induced for NO3- uptake. Membrane vesicles were isolated by means of Suc density gradient from roots exposed for 24 h either to 1.5 mM NO3- or 1.5 mM SO4-. The two populations of vesicles had similar composition as shown by diagnostic inhibitors of membrane-associated ATPases. However, both ATP-dependent intravesicular H+ accumulation and ATP hydrolysis were considerably enhanced (60-100%) in vesicles isolated from NO3--induced roots. Km for Mg:ATP and pH dependency were not influenced by NO3- treatment of the roots. ATP hydrolysis in plasma membrane vesicles for both control and NO3--induced roots was not affected by 10 to 150 mM NO3- or Cl-. On the other hand, kinetics of NO3-- or Cl--stimulated ATP-dependent intravesicular H+ accumulation were modified in plasma membrane vesicles isolated from NO3-- induced roots. Immunoassays carried out with polyclonal antibodies against plasma membrane H+-ATPase revealed an increased steady-state level of the enzyme in plasma membrane vesicles isolated from NO3--induced roots. Results are consistent with the idea of an involvement of plasma membrane H+-ATPase in the overall response of roots to NO3-.