Effects of plasmapheresis on the course of experimental allergic neuritis in rabbits

Experimental allergic neuritis was induced in 30 rabbits with extract of bovine peripheral nerve in complete Freund's adjuvant. Of the 22 animals that completed the study, nine animals were plasmapheresed within two weeks of inoculation and 13 animals served as controls. The plasmapheresed animals developed a less severe form of EAN than the controls. Differences were apparent in clinical weakness, weight loss, degree of dispersion of the muscle action potential and histological changes.     

A new method of measuring the deformability of the red cell membrane

Red cells moving in a stream of fluid can be arrested by means of a network of fibrin threads. Those cells which fold over a fibrin thread present to view a flat strap-like portion of membrane in which the strain can be easily observed and accurately measured both optically and by scanning electron microscopy. Preliminary results obtained by this method show elastic strains of nearly 300% and indicate that the stress required to produce these large strains is an order of magnitude greater than that reported by other methods.     

Gonadotropin stimulation of in vitro progesterone production in reptilian and amphibian ovaries.

The gonadotropic stimulation of progesterone production in vitro by preovulatory ovarian tissues from a chelonian reptile (Chelydra serpentina), crocodilian (Caiman sclerops), urodele amphibian (Ambystoma tigrinum) and anuran amphibian (Rana catesbeiana) was examined with a variety of mammalian and nonmammalian hormones, with emphasis on the homologous FSH and LH. In the turtle ovary, ovine (NIH) FSH was the most potent hormone while NIH-LH was relatively inactive. However, both FSH and LH from a turtle (Chelonia mydas) and crocodilian (Alligator mississipiensis) were effective; the two reptilian LHs appeared more potent than the FSHs. Similarly, both FSH and LH from the alligator and sheep effectively stimulated progesterone production by the Caiman ovary; in this case, Alligator-LH was the most potent steroidogenically.Results with postovulatory follicles and corpora lutea from the snapping turtle (Chelydra) were similar to those for preovulatory tissues. FSH from sheep and Chelydra were more potent than the respective LHs. Ovine LH was especially inactive in these tissues, but the homologous LH stimulated significant progesterone production.In contrast, only LH (ovine and amphibian were tested) stimulated progesterone release from the two amphibian ovaries. Rana-LH was more potent than ovine LH in Rana. In Ambystoma, both progesterone secretion and ovulation were observed over a wide range of doses of homologous LH, but FSH was inactive in both regards. Ovulation was inhibited while progesterone was maximal at the highest doses of LH.These comparative data suggest that the “primitive” tetrapod condition involved a relatively high specificity for LH for the control of ovarian progesterone production. This LH-specificity was apparently lost during early reptilian radiation, at least by the time that the captorhinids diverged into the extant orders. Since FSHs from diverse species are active in reptiles (and reptilian LHs but not FSHs are active in amphibians), the sensitivity to FSH in the reptilian ovary is viewed as being due to an alteration in gonadal receptors rather than to a structural change in the reptilian FSH molecule.     

Red cell membrane deformability: new data

Red cells arrested by fine fibers and subjected to drag forces in a moving stream of fluid can be stressed beyond the point of rupture. The technique, which is basically an in vitro analogue of the microangiopathic hemolytic state, thus permits a study of red cell behavior over the entire range of stress that the membrane can withstand. Measurements made by this approach show an exponential relationship between the velocity of fluid flow and the resultant membrane deformation. Such exponential membrane deformation is consistent with the morphology of red cell fragments and appears to explain their mechanism of formation.