Recalcification time in breast disease.

Hypercoagulability in malignant disease can be attributed, in part, to excess generation of tissue factor (thromboplastin) by the monocyte. Incubation of anticoagulated venous blood with endotoxin (a cellular activator) enables the generation of tissue factor by monocytes. The quantity of this procoagulant generated is determined by a simple recalcification time (a marker for cellular activation). Individuals with breast cancer have significantly shorter endotoxin-activated recalcification times than patients with cystic hyperplasia, who have, in turn, significantly reduced recalcification times when compared with those of healthy volunteers.

Experiences with an artificial sphincter to establish anal continence in dogs.

An implantable device for establishing urinary continence has been developed and has received FDA approval (AS 800, American Medical Systems, Inc.). The authors have applied this device to the control of anal continence in dogs. Fifteen mongrel dogs underwent either anal sphincter disruption (7) or abdominal-perineal resection (8). Such animals have bowel movements almost hourly. In each case, the device was implanted at the time of surgery. In dogs with working cuffs and disabled or absent sphincters, continence was maintained in seven out of 15 animals for periods of 4-8 hours. After cuff activation, intraluminal cuff pressures of 50-70 cm of water achieved continence for a period of 8 hours. In animals sacrificed from 1 to 12 months after implantation, the device was found to be well tolerated by the body with minimal fibrosis of the mucosa or muscularis of the bowel. Complications observed in the same four out of 15 animals during the study period were infection, device extrusion, and device malfunction. Infection resolved with local wound care and antibiotics (3/4) and the device was successfully replaced in two out of four instances of extrusion. With cuffs of proper size and pressure, this appliance may be effective in the control of human anal incontinence via the establishment of continent perineal colostomies following an abdominal-perineal resection.

Synthesis of the transferrin receptor by cultures of embryonic chicken spinal neurons.

We have purified a glycoprotein from chicken sciatic nerves, sciatin, which has pronounced trophic effects on avian skeletal muscle cells in culture. Recent studies have shown that sciatin is identical to the iron-transport protein, transferrin, in terms of its physicochemical structure, immunological reactivity, and biological activity. To determine whether transferrin is synthesized and released by neuronal tissue, we incubated cultures of dissociated chicken spinal neurons in a medium free of L-leucine containing either L-3H-amino acids or L-[14C]leucine and immunoprecipitated transferrin with highly specific antibodies. The radiolabeled protein precipitated by rabbit heteroclonal, goat heteroclonal, or mouse monoclonal antitransferrin antibodies increased in specific activity in a linear manner for at least 30 min. Synthesis of this protein was abolished by the presence of puromycin (20 micrograms/ml) or cycloheximide (10(-5) M). The disappearance of the radiolabeled protein from cells was linear with a half-life (t 1/2) of 8-10 h. When immunoprecipitates were separated by SDS gel electrophoresis, a prominent band corresponding to transferrin (Mr 84,000) was visualized by staining with Coomassie Blue. However, when such gels were fluorographed, no radioactivity was apparent in the transferrin region of the gel although a prominent radioactive band was visualized at an Mr of 56,000. The protein of Mr 56,000 was not simply a degradation product of transferrin because this particular protein band was not generated by incubating radiolabeled transferrin with unlabeled neuronal homogenates. The protein of Mr 56,000 was purified from embryonic chicken brain and spinal cord by immunoabsorption chromatography on mouse monoclonal antitransferrin IgG conjugated to Sepharose 4B followed by affinity chromatography on immobilized transferrin. The purified protein bound radioiodinated transferrin and was precipitated by rabbit anti-chicken transferrin-receptor antibodies. Furthermore, this receptor protein was found to be localized on the plasma membrane of dorsal root ganglion neurons by immunocytochemistry using the peroxidase-antiperoxidase technique, and by blocking experiments, which showed that antitransferrin receptor IgG could inhibit the binding of fluorescein-conjugated transferrin at 4 degrees C to cultured neurons in vitro. From these data, we conclude that transferrin is not synthesized by cultures of chicken spinal cord neurons, but that the receptor for transferrin is synthesized by these cultures and is precipitated by antitransferrin antibodies as an antigen-receptor complex.

Sciatin: immunocytochemical localization of a myotrophic protein in chicken neural tissues.

A mytotrophic protein (sciatin) purified from chicken sciatic nerves has "trophic" or "maintenance" effects on cultured muscle. We have elicited a specific antiserum against purified sciatin in rabbits. Using this antiserum, we investigated the distribution of sciatin in embryonic and adult chicken tissues by an unlabeled peroxidase-an-tiperoxidase method at the light microscopic level. The antiserum stained adult chicken neural tissues in situ and cultured embryonic chick neurons. Staining was intense in the cell bodies of spinal cord neurons and the axoplasm of sciatic nerves. These was reaction product seen in the outer margins of myelin sheaths that corresponded to the Schwann cell cytoplasm. Cerebral cortical neurons were weakly stained by the antiserum. No staining was apparent in oligodendrocytes or astrocytes. Nonneural tissues, such as skeletal, smooth and cardiac muscle, kidney, and liver, were also unstained by the antiserum. Cultured spinal cord neurons, cerebral cortical neurons, and sensory neurons were stained immunocytochemically by the antiserum. There was no reaction product seen in the glial cells that are usually present in neuronal cultures or cultured cells from liver, kidney, skeletal muscle, smooth muscle, and cardiac muscle. Our results thus show that the myotrophic protein is localized in neuronal perikarya and their processes in vivo as well as in vitro.