G3BPs tether the TSC complex to lysosomes and suppress mTORC1 signaling

Ras GTPase-activating protein-binding proteins 1 and 2 (G3BP1 and G3BP2, respectively) are widely recognized as core components of stress granules (SGs). We report that G3BPs reside at the cytoplasmic surface of lysosomes. They act in a non-redundant manner to anchor the tuberous sclerosis complex (TSC) protein complex to lysosomes and suppress activation of the metabolic master regulator mechanistic target of rapamycin complex 1 (mTORC1) by amino acids and insulin. Like the TSC complex, G3BP1 deficiency elicits phenotypes related to mTORC1 hyperactivity. In the context of tumors, low G3BP1 levels enhance mTORC1-driven breast cancer cell motility and correlate with adverse outcomes in patients. Furthermore, G3bp1 inhibition in zebrafish disturbs neuronal development and function, leading to white matter heterotopia and neuronal hyperactivity. Thus, G3BPs are not only core components of SGs but also a key element of lysosomal TSC-mTORC1 signaling.

Prognostic value of central venous pressure in acute myocardial infarction

The investigations were carried out in 296 patients with myocardial infarction (238 men and 58 women) aged 24-91 years, admitted to an intensive care unit on the 1st or 2nd day of the disease. In all patients the catheter for determination of central venous pressure was introduced into the right atrium through the cephalic vein the the first 100 cases, and through the subclavian vein in 196 cases. The catheter was kept in the atrium for 3-4 days. Values of c.v.p. between 50 and 120 mm Hg were accepted as normal.

Hyperlipoproteinemia (acc. to Fredrickson's classification) in patients with myocardial infarction and imminent infarction

In 500 cases (379 men and 121 women) of ischemic heart disease, including 428 patients with myocardial infarction and 72 -- with imminent infarction, blood lipid levels were determined. Blood samples were taken on fasting, by the end of hospitalization, from patients with myocardial infarction on the 18th-21st day of disease, and from those with imminent infarction after cessation of pain. In 152 patients (30.4%), including 87 with infarction and 65 with imminent infarction, disturbances in the blood lipid pattern were found and classified according to Fredrickson. When expressed as percentage against the material of 152 patients with blood lipid disturbances, type II A was found in 103 cases (67.8%), type II B -- in 25 cases (16.4%), and type IV -- in 24 cases (15.8%). When calculated against the whole material of 500 patients, type II A accounted for 20.6%, type II B -- for 5%, and type IV -- 4.8% of cases.

Early diagnosis of myocardial infarction by arginase activity determination

In blood serum of healthy persons the activity of arginase (EC 3.5.3.1) is very low, whereas in patients with myocardial infarction it increases within a few hours after the first attack of coronary pain, and returns to normal values after 3-5 days. No increase of arginase activity was observed in sera of patients with angina pectoris, coronary insufficiency or cardiac failure. Determination of arginase activity in blood serum may serve as a useful test in early differential diagnosis of myocardial infarction.