Pharmacokinetics of hemoglobin-based oxygen carrier hemoglobin-glutamer-200 bovine (oxyglobin) in the horse

Oxyglobin (OXY) is a hemoglobin‐based oxygen carrier (HBOC) made of glutaraldehyde‐polymerized bovine hemoglobin (bHb). Products similar to OXY are under development for use as temporary blood substitutes in trauma, shock and anemia. Since they all may increase blood O₂‐carrying capacity and thus, possibly tissue oxygenation, they may also be used to enhance performance of both equine and human athletes. That is why HBOCs are banned from use in athletic competition. Our goal was to determine the pharmacokinetics of OXY after intravenous (IV) infusion to horses. Blood and urine samples were collected from adult horses that received an IV dose of 32.5 g of OXY. Concentrations of OXY in plasma and urine were quantified using a newly developed LC/Q‐TOF‐MS/MS detection technique. Level of quantification (LOQ) was 50 μg mL^–1. The decline of the plasma concentration‐time curve of the HBOC was described by a 2‐compartment model (C1 and C2). The median distribution alpha (t1/2k1,0) and elimination beta (t1/2k2,0) half‐lives were 1.3 and 12.0 hours, respectively. The bHb molecules in OXY are not of uniform size and vary substantially in molecular weight (MW). Of the OXY molecules 53% were eliminated in C1, which represented the smaller MW molecules and 47% in C2, which represented the larger MW bHb. The maximal 0‐time plasma concentration was 662.0 μg/mL and declined to 97.1 μg mL^–1 at 24 h. The area below the plasma concentration‐time curve was 5143 μg h^–1 mL^–1. The volumes of C₁ and C₂ were 86.9 and 63.9 mL kg^–1, respectively. Oxyglobin was not detected in urine. This study shows the detection and quantification in equine plasma of a HBOC following IV infusion and demonstrates the short half‐life of about 50% of infused bHb molecules.     

BOOK REVIEWS

Book reviewed in this article:
Guide to the Dissection of Domestic Ruminants . RE Habel
Biology and Medicine of Rabbits and Rodents . JE Harkness and JF Wagner     

Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows

Objective To evaluate the effect of the number of days exposure to a prepartum transition diet on reproduction and health in dairy cows. Design A prospective cohort study. Procedures We enrolled 1008 dairy cows from three herds to examine the effects on reproduction and health of increased days exposure to prepartum transition diets that included ryegrass pasture, ryegrass silage, cereal hay, grain, by-products, oilseed meals, BioChlor®, rumen modifiers, minerals and vitamins. Diets provided 9.9 MJ metabolisable energy per kg dry matter (DM), a metabolisable protein balance of 286 g/day and a dietary cation anion difference of −150 meq/kg DM. Statistical models controlled for herd, calving day, age and gestation period. Results In two of the three herds increased days exposure to prepartum transition diets increased the hazards of submission for breeding, conception and clinical mastitis, and decreased the hazard of cow removal. The odds of pregnancy by 6 and 21 weeks after the mating start date tended to increase with increasing days of exposure to prepartum transition diets. Conclusions Increasing exposure to a prepartum transition diet improved the calving to conception interval, tended to improve the odds of pregnancy and reduced the risk of culling of cattle, but increased the hazard of clinical mastitis.     

Mg/Ca Thermometry in Coral Skeletons

The magnesium-to-calcium (Mg/Ca) ratio of coral skeletons from Ishigaki Island, Ryukyu Islands, Japan, closely tracked sea surface temperature (SST) over an 8-year period. Measurements were made with the fast technique of inductively coupled plasma-atomic emission spectrometry. The variation of the coral Mg/Ca ratio with SST change is about four times that of the current, widely used coral strontium-to-calcium ratio. The temporal and geographic variation of the seawater Mg2+/Ca2+ ratio probably has little influence on coral Mg/Ca variation. Results indicate that the coral Mg/Ca ratio has the potential to provide fast, precise, high-resolution proxies for past tropical SSTs.     

A survey of urinary tract disease in New South Wales koalas

From 1980 to 1988 235 koalas were necropsied and 67 were found to have urinary tract disease. Six affected koalas out of 48 were derived from wildlife parks around Sydney while 61 of 187 were derived from free living populations on the central and north coasts of New South Wales. Sixteen had cystitis alone, 5 had cystitis and associated renal disease only, 16 females had cystitis with genital disease, 23 had urinary disease in combination with other systemic disease and 7 had renal disease only. Overall 49 animals had cystitis (30 females and 19 males; 47 being free living) with 12 of these having renal extension (all free living). Cystitis tended to be active but chronic while associated renal disease was mainly designated as hydronephrosis and pyelonephritis. Other forms of renal disease included lymphosarcoma, oxalate nephrosis, acute and chronic nephritis, and microabscessation related to septicaemia. Female genital disease associated with cystitis was commonly vaginitis and metritis. Paraovarian cysts were detected with and without metritis. Other diseases occurring with urinary tract disease included conjunctivitis, dermatitis/stomatitis, pneumonia and hepatic disease. The higher prevalence of urinary tract disease in free living koalas, especially cystitis, is in contrast to captive koalas and may reflect the interaction between disease cause and habitat.     

Phenotypic and genotypic characterisation of Pasteurella multocida isolated from pigs at slaughter in New Zealand

AIMS: To examine pigs at slaughter in New Zealand for the presence of Pasteurella multocida, and to determine for isolates, their biochemical profiles, somatic and capsular types, and the presence or absence of the HSB and toxA genes, associated with haemorrhagic septicaemia (HS) and progressive atrophic rhinitis (PAR), respectively.

METHODS: Swabs from 173 lungs, 158 palatine tonsils and 82 nasal passages of pigs at two abattoirs in New Zealand were cultured for P. multocida using conventional techniques, and isolated colonies were subjected to biochemical tests for identification of biovars. Somatic serotyping was conducted using an agar gel immunodiffusion (AGID) test. Polymerase chain reaction (PCR) assays were used to confirm phenotypic identification of colonies using species-specific primers, capsule type using serogroup-specific primers and multiplex PCR, and to test for the presence of HSB and toxA genes.

RESULTS: Pasteurella multocida was isolated from 11/173 (6.4%) lung, 32/158 (20.2%) palatine tonsil and 5/82 (6.1 %) nasal swab samples, a total of 48 isolates from 413 samples (11.6%). Isolation rates per farm ranged from 1–53% of tissue samples collected from pigs 5–6 months of age. On phenotypic characterisation, isolates were allocated to seven main biovars, viz 1, 2, 3, 5, 9, 12, and a dulcitol-negative variant of Biovar 8, the majority (30/48) being Biovar 3. Of the 42 isolates for which somatic serotyping was conducted, 10% were Serovar 1, 79% were Serovar 3, 2% were Serovar 6,1, 2% were Serovar 12, and 7% could not be typed. All 48 isolates were confirned as P. multocida using a species-specific PCR. In the capsular multiplex PCR, 92% of isolates were Capsular (Cap) type A, 2% were Cap D, and 6% could not be typed. None of the samples were positive for the HSB or toxA genes.

CONCLUSION: Serovars or capsular types of P. multocida associated with HS or PAR in pigs were not detected. Establishment of species-specific, capsular and toxin PCR assays allowed the rapid screening of isolates of P. multocida, while serotyping provided an additional tool for epidemiological and tracing purposes.