Strontium Uptake in Shell Aragonite from the Freshwater Gastropod Limnaea stagnalis

Shell aragonite from 96 specimens of the freshwater gastropod Limnaea stagnalis grown in laboratory tanks at different temperatures in water with variable strontium/calcium ratios have been analyzed for its strontium content in order to evaluate the mechanisms of strontium uptake in molluskan aragonite. Within the limits defined by natural freshwater environments, the strontium/calcium ratio in the aragonite was found to be linearly related to the strontium/calcium ratio in the water. A distribution coefficient k(A)(Sr) = 0.237 +/- 0.029, unaffected by variations in temperature and growth rate, has been found. This finding substantiates the existence of a strontium-discriminating effect in aragonite precipitated by mollusks as compared to the case for nonbiogenic aragonite which contains about five times as much strontium when precipitated under the same conditions.     

Necrotizing enteritis in suckling pigs (Clostridium perfringens type C enterotoxemia). II. Toxin formation, heat and drug resistance of Clostridium perfringens strains isolated from suckling pigs and broilers with necrotizing enteritis]

Nineteen Clostridium perfringens Type C strains and ten foreign control strains of subtypes C1, C3, and C4 were tested for their toxin formation and spore resistance to heat. The 19 Type C strains had been isolated from unweaned piglets in the context of necrotising enteritis outbreaks in the GDR. The Clostridium perfringens Type C strains formed beta-toxin, but they failed to form epsilon-toxin or gamma-toxin, alpha-toxin was successfully recorded from 15 of the 19 strains tested from unweaned piglets. The minor-lethal toxin fractions were also tested, with delta-toxin being recorded from all strains, non-alpha-delta-theta-toxin from six, theta-toxin from five, and K-toxin from one. Tests for delta-toxin, lambda-toxin, and mu-toxin were negative. The Clostridium perfringens Type C strains isolated in the GDR from unweaned piglets with necrotising enteritis were, basically, identical with those described in Denmark by von Hogh (1967) with regard to toxin formation. Clostridium perfringens strains cultured in broilers with necrotising enteritis were characterised by regular toxin production in the context of alpha, theta, delta as well as non-alpha-delta-theta. They failed to form beta, epsilon, gamma and lambda, while mu-toxin was formed by them quite irregularly. They, consequently, are Type A strains. Resistance to chloramphenicol and/or oxytetracycline was exhibited by 78.5 per cent of 237 tested Clostridium perfringens strains which had been isolated from unweaned piglets and broilers with necrotosing enteritis. Multiple resistance was recorded from 33.9 per cent. All strains were susceptible to penicillin, nitrofurantoin, and erythromycin.     

THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS

Infectious avian encephalomyelitis virus (IAEV) maternal antibody was detected in the serum of chickens for up to 21 days following hatching. This antibody protected chickens against clinical IAE after intracerebral inoculation with van Roekel strain or oral administration of the NSW-1 strain of IAEV. Maternal antibody to IAEV also protected testosterone bursectomised chickens against the development of clinical disease. IAEV maternal antibody also influeced the pattern of virus excretion in faeces and serological responsiveness. This influence on antibody responses persisted beyond the time that IAEV maternal antibody could be detected. The importance of IAEV maternal antibody on the strategy of vaccination against IAE is discussed.     

Indirect solid-phase microradioimmunoassay for detection of pseudorabies virus antibody in swine sera.

An indirect solid-phase microradioimmunoassay (IRIA) was developed for detection and quantitation of antibodies to pseudorabies virus (PRV) in swine serum. Qualitative results of the IRIA compared closely with results of the serum neutralization test (NT) and the microimmunodiffusion test (MIDT). The IRIA was more sensitive than the NT for detection of antibodies to PRV in swine serum. The IRIA result is expressed numerically. With the IRIA and NT, antibody to PRV was first detectable in 3 experimentally infected pigs at 9 days after inoculation. With MIDT, antibody was detected in the 3 experimentally infected pigs at 9 days after inoculation. With the MIDT, antibody was detected in the 3 experimentally infected pigs at 7, 8, and 9 days after inoculation. The IRIA results are obtainable within a few hours; the NT and MIDT require 48 hours for completion.     

Effect of the proteinase inhibitor aprotinin in the management of hemorrhagic shock in the dog.

Aprotinin, a proteinase inhibitor, was evaluated as a pharmacologic aid in dogs subjected to lethal hemorrhagic shock. Survival time, hemodynamic changes, and plasma enzyme analysis were measured as criteria for drug effects. Mixed-breed dogs (n = 14) were divided into 2 groups of 7 each: nontreated dogs in shock (group 1) and aprotinin-treated dogs in shock (group 2). One of 7 dogs in group 1 and 2 of 7 dogs in group 2 survived. Survival time, for the remaining dogs in group 1 (190 min, n = 6) and group 2 (188 min, n = 5) were not significantly different. There was no significant difference in mean arterial pressure, mean pulmonary arterial pressure, cardiac output, or left ventricle systolic pressure associated with aprotinin treatment at any time after hemorrhagic shock. There was no significant difference in plasma lactic acid, aspartate aminotransferase, alanine aminotransferase, creatine phosphokinase, alpha-amylase, and beta-glucuronidase associated with treatment at any time; however, there were significant (P less than 0.05) increases with time. The gastrointestinal tract was the site of most obvious lesions found at necropsy. Lesions varied considerably in extent and severity without apparent correlation to the treatment regimen. These experiments did not show beneficial effects of aprotinin in dogs subjected to hemorrhagic shock, but neither did they completely rule out some valuable actions that may have been obscured by the type of model used.