Rear limb paralysis in market age swine occurs sporadically and can be attributed to a variety of causes, including fractures, spinal abscesses, and ischemic myelomalacia due to cartilage (fibrocartilage) emboli from the nucleus pulposus. 11,16 Cartilage emboli resulting in ischemic myelomalacia have been reported in several species, most commonly in adult large-and giant-breed dogs and rarely in swine. [4][5][6]9,10,[14][15][16] In a recent report, there was a high incidence of rear limb paresis/paralysis in a large group of finishing pigs caused by ischemic myelomalacia due to fibrocartilage emboli in the spinal cord. 3 However, no factors were identified in the affected pigs that predisposed them to development of cartilage emboli. In this follow-up report to that case, we describe an additional group of finishing pigs with ischemic myelomalacia caused by cartilage emboli. These pigs also had chronic diskospondylitis.Market weight swine in a production unit with approximately 1,800 grow-finish swine developed a high incidence of acute rear limb paralysis following transportation to market (25/1,800 swine affected). 3 These swine were from a high-lean, heavily muscled genetic line that had a rapid growth rate, and they were extremely large (127 kg) when transported. Nine of these paralyzed swine were submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL) for necropsy. All 9 of these swine had ischemic myelomalacia associated with cartilage emboli in spinal cord vessels. However, abnormalities in the spine were not detected, and a predisposing cause for the cartilage emboli was not discovered. Several weeks later, acute rear limb paralysis developed in several market weight swine in additional groups (500 swine/group) from the same production unit. The circumstances of this episode were similar to those of the previous episode of paralysis, occurring after transportation to market. Five paralyzed swine were submitted to the ISU-VDL for necropsy and complete examination of the spinal cord and spine. The spinal cords were removed following dorsal laminectomy, and the spines were sectioned longitudinally with a bandsaw in a dorsoventral vertical plane. Sections of vertebrae, intervertebral disks, and the entire spinal cords from all 5 pigs were fixed in 10% neutral buffered formalin. Vertebrae were demineralized in a 25% aqueous solution of formic acid, and all tissues were embedded in paraffin, sectioned at 5 m, and stained with hematoxylin and eosin. Replicate sections were stained with Alcian blue at pH 2.5 to identify fragments of nucleus pulposus.From the Department of Veterinary Pathology and the Veterinary
The isosteric heat of adsorption qat of krypton on an 82% Ca-exchanged Y zeolite was obtained at a surface coverage corresponding to about one krypton per 64 supercages. The value of q.,t, calculated from adsorption isotherms taken at pressures between 5 and 180 torr and temperatures between 0°and 150°C ., was found to be 5.3 kcal. per mole after prior evacuation of the adsorbent at 410°C. and 4.6 kcal. per mole when the sample was heated above 700°C. in vacuo before adsorption. These values must be compared with a calculated heat of adsorption of about 20 kcal. per mole, largely due to polarization energy if krypton were adsorbed at Ca2+ ion sites at the window between supercage and sodalite cage. It is concluded that such sites, if present at all, must represent a fraction less than about 10~7 of all the sites available to krypton. Thus, the large electrostatic fields associated with these bivalent cation sites play an insignificant role in the adsorption of krypton. Similar conclusions have been reached by measuring q,( on Y samples containing Mg2+, Sr2+, Ba2+, and Fe2+. It is proposed that krypton is adsorbed at effectively univalent sites consisting of a single M2+ associated with OHor of two M2+ ions bridged by a O2ion, depending on the degree of dehydroxylation of the sample.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.