Malignant hyperthermia in a Greyhound

A rapid rise in rectal temperature (to 45 C) in a young male Greyhound was attributed to the use of halothane and succinylcholine. Circulatory failure and death occurred within approximately 90 minutes of the onset of the hyperthermia.     

Effect of magnesium deficiency in the hen on egg production and hatchability of eggs

The influence of the level of magnesium (Mg) in the ration on reproduction by the hen was studied in 2 experiments. In experiment 1, it was found that feeding a semi‐purified ration, containing 56 p.p.m. of Mg, resulted in decreased egg production and reduced serum Mg concentration within 10 to 14 days. Although fertility of eggs was not affected noticeably by Mg deficiency, hatchability of fertile eggs was decreased markedly. The influence of inadequate dietary Mg was partially alleviated by adding 250 p.p.m. Mg to the ration. In experiment 2, a decline in hatchability preceded decreases in egg production and food consumption. A decrease in Mg concentration in egg contents accompanied the decline in hatchability. Hens fed rations containing 50 or 150 p.p.m. added Mg produced eggs of relatively low hatchability by day 14 of the trial. Subsequent to being fed a ration containing 550 p.p.m. added Mg, these hens increased in rate of egg production while hatchability of fertile eggs also increased. The results indicate that the dietary Mg requirement of the laying hen, sufficient to maintain a high rate of production of eggs which hatch satisfactorily, is 400 or more p.p.m.     

Binding of Salmonella strains to immobilized intestinal mucosal preparations from broiler chickens.

The binding kinetics of radiolabeled Salmonella california 1989/O (mannose-sensitive hemagglutinin-positive [MSHA+]) to immobilized mucus or enterocytes isolated from broiler ceca and inhibition of binding by D-mannose and sodium metaperiodate were characteristic of adherence of mannose-sensitive type 1 fimbriae of bacteria to eukaryotic mannose-containing receptors. Binding by radiolabeled strains 1989/O (in the presence of D-mannose) and S. typhimurium S 7471 N (MSHA-, non-fimbriated) indicated non-specific binding that was characterized by less binding to enterocytes and mucus and lack of inhibition by carbohydrates or prior treatment with sodium metaperiodate. Inhibition of non-specific binding to enterocytes by pretreatment with various enzymes or by the presence of tetramethylurea or p-nitrophenol (known to disrupt hydrophobic interactions) indicate involvement of multiple sites and hydrophobic bonding. Strain-specific outer-membrane preparations inhibited non-specific binding to a greater extent than did lipopolysaccharide, Escherichia coli outer-membrane preparations, or bovine serum albumin.     

Species of Staphylococcus isolated from animal infections

One hundred randomly selected clinical strains of staphylococci were identified by species using a commercial micromethod system. Eight species of staphylococci were identified. Staphylococcus intermedius was the most frequent (n = 74) species identified and accounted for 70/74 (94.6%) of the coagulase-positive strains and 70/79 (88.6%) of the total isolates from dogs. Other species identified, in order of their frequency, included S. epidermidis (8), S. aureus (7), S. simulans (4), S. sciuri (2), S. xylosus (2), S. hyicus (2) and S. saprophyticus (1). These results show that at least 8 different species of staphylococci can be recovered from animal infections and that coagulase-positive species such as S. intermedius may be more common than S. aureus. The relative significance of these other species in animal infections needs to be assessed.     

Cultivar mixtures for the simultaneous management of multiple diseases: tan spot and leaf rust of wheat

ABSTRACT Because of differences in life histories between Puccinia triticina, a highly specialized, polycyclic, windborne pathogen with a shallow dispersal gradient, and Pyrenophora tritici-repentis, a residue-borne pathogen with a steep dispersal gradient, wheat mixtures are expected to be more effective at controlling leaf rust than tan spot. The objectives of this research were to determine the effect of two-cultivar mixtures with varying proportions and different pathogen resistance profiles on the severity of tan spot and leaf rust, to evaluate yield of the mixtures in the presence or absence of disease, and to directly compare the relative effectiveness of cultivar mixing for tan spot versus leaf rust. In a field experiment at two sites in Kansas over two growing seasons, winter wheat cvs. Jagger and 2145, which have differential resistance reactions to leaf rust and tan spot, each were planted in proportions of 0.25, 0.50, 0.75, and 1.00. Plots were inoculated with each pathogen alone, both pathogens, treated with a fungicide, or exposed to ambient conditions. For both diseases for all siteyears, severity decreased substantially on the susceptible cultivar as the proportion of that cultivar decreased in mixture. Mixtures were significantly more effective at reducing leaf rust than tan spot in three of four site-years. Mixtures generally yielded the same as the weighted mean of components in monoculture although, in two of three site-years, at least one fungicide-treated and one diseased mixture each yielded higher than expected values. Although this particular mixture produced only modest yield benefits, the potential for simultaneous reductions in tan spot and leaf rust was demonstrated.     

Allometric analysis of ciprofloxacin and enrofloxacin pharmacokinetics across species

The purpose of this study was to examine the allometric analysis of ciprofloxacin and enrofloxacin using pharmacokinetic data from the literature. The pharmacokinetic parameters used were half-life, clearance and volume of distribution. Relationships between body weight and the pharmacokinetic parameter were based on the empirical formula Y = aW(b), where Y is half-life, clearance or volume of distribution, W the body weight and a is an allometric coefficient (intercept) that is constant for a given drug. The exponential term b is a proportionality constant that describes the relationship between the pharmacokinetic parameter of interest and body weight. A total of 21 different species of animals were studied. Results of the allometric analyses indicated similarity between clearance and volume of distribution as they related to body weight for both drugs. Results of the current analyses indicate it is possible to use allometry to predict pharmacokinetic variables of enrofloxacin or ciprofloxacin based on body size of species. This could provide information on appropriate doses of ciprofloxacin and enrofloxacin for all species.