Purified plasma membranes were obtained from five transplantable human tumors, a Grade IV astrocytoma, an oat cell carcinoma, and three melanomas. Plasma membrane fractions were isolated from tumor homogenates by differential and discontinuous sucrose gradient centrifugation. Determination of enzyme activities indicated that the plasma membranes were enriched 10to 20-fold with respect to 5'-nuc...

Acetaldehyde may be the injurious agent in acute alcoholic liver disease. It has been suggested that the mechanism of liver injury in this situation may be immunologically mediated. In the present study acetaldehyde has been bound to human liver plasma membranes. The activation of C3 by the acetaldehyde/membrane product was measured by immunofixation of the separated C3 components. Activation o...

?2 microglobulin (?2m) fibril has been recognized as the major factor of dialysis-related amyloidosis. elevated serum levels are thought to be the basis for tissue deposition. in order to evaluate the effect of cellulosis membrane (fb 110) and treatment duration on s?2m levels, we determined serum levels in 23 hemodialyzed patients with end-stage renal failure. s?2m levels were markedly elevate...

Because human platelets participate in the contact phase of intrinsic coagulation and contain a Factor XI-like coagulant activity, the nature of the Factor XI-like activity was examined and compared with purified plasma Factor XI. The platelet factor XI-like activity was sedimented with the particulate fraction of a platelet lysate, was inactivated by heat (t(1/2) 3.5 min, 56 degrees C), was no...

Plasma membranes were isolated from both unfrozen and frozen tissues of Jerusalem artichoke tubers (Helianthus tuberosus L.) in high purity utilizing an aqueous two-polymer phase partition system. Although the recovery of the plasma membranes was decreased significantly by freezing of tissues even at the nonlethal temperature (-5 degrees C), the isolated plasma membrane samples were considered ...

1. The mechanism responsible for the failure of insulin to activate pyruvate dehydrogenase (PDH) in white adipose tissue in vivo during lactation was investigated. 2. Insulin failed to increase PDH in isolated adipocytes from lactating rats. 3. Insulin binding to plasma membranes from adipocytes was unchanged by lactation. 4. Incubation of plasma membranes plus permeabilized mitochondria from a...

Retinal pigment epithelial cell plasma membranes were isolated from the eyes of normal and RCS-dystrophic rats by binding glass microbeads to the intact pigment epithelial cell layer, removal of the bead-bound cells from the eyes and subsequent sucrose density gradient centrifugation. Plasma membranes were recovered from the gradients in identical yields and characterized by membrane marker enz...

Calcium specifically binds to adipocyte plasma membranes, demonstrating two classes of binding sites having affinity constants of 4.5 x 10(4) M-1 and 2.0 x 10(3) M-1. Insulin (100 microunits/ml) added directly to the isolated plasma membranes caused no alteration in calcium binding, whereas incubation of the adipocytes with 100 microunits/ml of insulin resulted in a 2.50 +/- 1.6% increase in ca...

Niemann-Pick type C (NPC) disease is a neuro-visceral cholesterol storage disorder caused by mutations in the NPC-1 or NPC-2 gene. In the present paper, we studied IR (insulin receptor) activation and the plasma-membrane lipid assembly in primary hepatocytes from control and NPC1-/- mice. We have previously reported that, in hepatocytes, IR activation is dependent on cholesterol-sphingolipid ra...

This study was performed to evaluate the protective effects of pyrroline and pyrrolidine nitroxides Pirolin, PL, and Pirolid, PD, on the plasma membranes of rat cardiomyocytes treated in vitro with anthracycline drugs aclarubicin (ACL) and doxorubicin (DOX). The influence of two concentrations of drugs (10 and 20 microM) and nitroxides (0.1 and 1 mM) as well as their combinations (a drug and a ...