Effects of Bos taurus autosome 9-located quantitative trait loci haplotypes on the disease phenotypes of dairy cows with experimentally induced Escherichia coli mastitis.

Several quantitative trait loci (QTL) affecting mastitis incidence and mastitis-related traits such as somatic cell score exist in dairy cows. Previously, QTL haplotypes associated with susceptibility to Escherichia coli mastitis in Nordic Holstein-Friesian (HF) cows were identified on Bos taurus autosome 9. In the present study, we induced experimental E. coli mastitis in Danish HF cows to investigate the effect of 2 E. coli mastitis-associated QTL haplotypes on the cows' disease phenotypes and recovery in early lactation. Thirty-two cows were divided in 2 groups bearing haplotypes with either low (HL) or high (HH) susceptibility to E. coli. In addition, biopsies (liver and udder) were collected from half of the cows (n=16), resulting in a 2 × 2 factorial design, with haplotype being one factor (HL vs. HH) and biopsy being the other factor (biopsies vs. no biopsies). Each cow was inoculated with a low E. coli dose (20 to 40 cfu) in one front quarter at time 0 h. Liver biopsies were collected at -144, 12, 24, and 192 h; udder biopsies were collected at 24h and 192 h post-E. coli inoculation. The clinical parameters: feed intake, milk yield, body temperature, heart rate, respiration rate, rumen motility; and the paraclinical parameters: bacterial counts, somatic cell count (SCC), and milk amyloid A levels in milk; and white blood cell count, polymorphonuclear neutrophilic leukocyte (PMNL) count, and serum amyloid A levels in blood were recorded at different time points post-E. coli inoculation. Escherichia coli inoculation changed the clinical and paraclinical parameters in all cows except one that was not infected. Clinically, the HH group tended to have higher body temperature and heart rate than the HL group did. Paraclinically, the HL group had faster PMNL recruitment and SCC recovery than the HH group did. However, we also found interactions between the effects of haplotype and biopsy for body temperature, heart rate, and PMNL. In conclusion, when challenged with E. coli mastitis, HF cows with the specific Bos taurus autosome 9-located QTL haplotypes were associated with differences in leukocyte kinetics, with low-susceptibility cows having faster blood PMNL recruitment and SCC recovery and a tendency for a milder clinical response than the high-susceptibility cows did.

Oral transmission as a route of infection for viral haemorrhagic septicaemia virus in rainbow trout, Oncorhynchus mykiss (Walbaum).

Surveys among wild marine fish have revealed occurrence of viral haemorrhagic septicaemia virus (VHSV) infections in a high number of diverse fish species. In marine aquaculture of rainbow trout, preying on invading wild fish might thus be a risk factor for introduction and adaptation of VHSV and subsequent disease outbreaks. Our objective was to determine whether an oral transmission route for VHSV in rainbow trout exists. Juvenile trout were infected through oral, waterborne and cohabitation transmission routes, using a recombinant virus strain harbouring Renilla luciferase as reporter gene. Viral replication in stomach and kidney tissue was detected through bioluminescence activity of luciferase and qRT-PCR. Replication was detected in both tissues, irrespective of transmission route. Replication patterns, however, differed among transmission routes. In trout infected through oral transmission, replication was detected in the stomach prior to kidney tissue. In trout infected through waterborne or cohabitation transmission, replication was detected in kidney prior to stomach or in both tissues simultaneously. We demonstrate the existence of an oral transmission route for VHSV in rainbow trout. This implies that preying on invading infected wild fish is a risk factor for introduction of VHSV into marine cultures of rainbow trout.

General and family-specific gene expression responses to viral hemorrhagic septicaemia virus infection in rainbow trout (Oncorhynchus mykiss).

The ability of rainbow trout (Oncorhynchus mykiss) to respond successfully to infection by viral hemorrhagic septicaemia virus (VHSV) is expected to involve a large number of biochemical processes. We hypothesized that this would be reflected at the gene expression level in infected fish, and we tested it by examining gene expression levels in the head kidney of trout at a genome-wide scale with a 16K cDNA microarray for salmonids. Expression levels were recorded during 16 days following bath challenge. The challenge experiment included a relatively low susceptibility (32% survival following challenge) and a relatively high susceptibility (18% survival following challenge) trout family that were both split into a group exposed to virus and a non-exposed control group. In total, 939 genes were differentially expressed between infected and non-infected fish (FDR p=0.05). Five groups of Gene Ontology categories were involved in immune-related processes and over-represented in infected fish: (i) stress and defense response, (ii) NFkappaB signal transduction, (iii) response to non-self, (iv) antigen processing and presentation, and (v) proteasome complexes. The first four categories were also over-represented among the 642 differentially expressed genes in the low-susceptibility trout family but not among the 556 differentially expressed genes in the high-susceptibility trout family. Expression profiles for most immune genes discussed showed increased transcription from day 3 post-challenge. The results suggest that the innate immune system may play an important role in the successful response to VHSV in rainbow trout. In addition, the results indicate that a superior regulation of the transcription of several key innate immune-related genes contribute to the increased survival in resistant fish.

Short communication: Born to be a loser cow?

Over the last few years, an increasing awareness has arisen in Denmark of the existence of cows with a generally lowered health and production status, referred to as "loser cows." A previous study has estimated that the overall prevalence of loser cows in Danish Holstein herds is 3.2%. The aim of this study was to estimate genetic and phenotypic parameters for the loser cow state and the underlying traits: lameness, hock lesions, other cutaneous lesions, and condition of hair coat. Records on 6,098 cows were analyzed with an animal model including fixed effects of herd, season of scoring and location of scoring, age at first calving, lactation stage, and parity in addition to additive genetic effects and permanent environmental effects. The heritability of the loser cow score was 0.08 and for the underlying traits the heritability ranged from 0.05 to 0.12. The genetic correlations between various pairs of traits included in the loser cow score ranged from 0.04 to 0.68 and the phenotypic correlations ranged from 0.09 to 0.21. The genetic and phenotypic correlations between the loser cow score and the underlying traits ranged from 0.25 to 0.89 and 0.20 to 0.85, respectively, supporting the concept of the loser cow score. The traits included in the loser cow score are easy to assess and all showed genetic variation. They are therefore suitable for inclusion in a total merit index aimed at breeding for more robust cows.

External dose rates in radioiodine treatment of benign goitre: estimation versus direct measurement.

OBJECTIVE: According to European recommendations, the external dose rate (ED) in radioiodine-treated goitre patients can be determined by estimating from calculation of the residual activity (RA) in the patient based on radioiodine uptake measurements or by measuring ED directly. In the European guidelines, "Radiation Protection 97", it is assumed that an RA of 600 MBq (131)I causes an ED of 30 microSv/h at a distance of 1 m. This implies a slope of 0.05 microSv/h/MBq for the ratio ED/RA relationship, but, theoretically, this ratio is higher, at 0.07, a difference that is due to measurement in air versus in a scattering medium. We sought to investigate what the true ratio might be. MATERIAL AND METHODS: Sixty-six patients scheduled for radioiodine treatment of benign goitre (mean size 102 mL, range 20-440), who received (131)I orally (mean 984 MBq, range 173-3700) were examined. After 24 h and 96 h iodine uptake percentage we examined 7269 patients scheduled for radioiodine treatment of benign goitre (mean size 1042 mL, range 20-440) who received (131)I orally (mean 101,100 MBq, range 180-3700). After 24 h and 96 h, the iodine uptake was determined, RA calculated and ED measured using a hand-held dosimeter. RESULTS: At 24 and 96 h, we observed a slope ratio of 0.103 microSv/h/MBq (95 % CI: 0.09564-0.111) and 0.101 microSv/h/MBq (95 % CI: 0.0915-0.11107), respectively, for the ED/RA relationship. None of the confidence intervals included the value 0.05 microSv/h/MBq, reflecting that the observed slopes differed significantly from the expected slope (p < 0.001). Consequently, an RA of 600 MBq typically causes an ED of 60 and not 30 microSv/h, and therefore dose rates based on radioiodine uptake measurements and established assumptions were only about half as high as the directly measured values. We noticed that with an RA roughly below 450 MBq, the anticipated slope of 0.05 microSv/h/MBq is within the prediction interval of our claimed ratio, therefore we cannot rebut the anticipated slope for lower doses. CONCLUSIONS: Dose-rate estimates based on radioiodine uptake measurements and established assumptions were only about half as high as the directly measured values in patients receiving doses higher than the widely accepted limits for outpatient treatment. This finding may have substantial implications for us, in that it makes a considerable difference whether the radiation precautions are taken to limit doses to the patient's surroundings and for deciding if a patient may or may not be regarded as an outpatient, as well as for the safe discharge of an inpatient from hospital.

Flow cytometric measurement of intracellular pH in B16 tumors: intercell variance and effects of pretreatment with glucose.

Flow cytometry was used to measure cytoplasmic pH (pHi) of B16 melanoma cells taken from tumor-bearing animals. We used a ratiometric method to allow measurements on an individual cell basis which were independent of cellular content of the pH indicator BCECF. In order to "freeze" any intercell variance which may have existed within the tumor mass, tumors were mechanically disaggregated in bicarbonate-free medium containing 0.5 mM amiloride at 4 degrees C and loaded with BCECF in choline chloride-based Earle's solution at 37 degrees C. Studies using cells grown in vitro showed that this protocol prevented acid load recovery during the 30-min period typically required between tumor excision and pHi measurement. A calibration curve was obtained by resuspending BCECF-stained cells in a range of buffers containing the proton ionophore nigericin. The range of values for individual cells was estimated by comparing the coefficient of variation of the test sample with that obtained when nigericin was used to reduce all cells to the pHi of the calibration buffer. The average value for mean tumor cell pH was 7.32 +/- 0.05 SD. Pretreatment of animals with intraperitoneal glucose for one hour resulted in an average for mean pHi of 7.17 +/- 0.17 SD. Mean coefficient of variation was 8.7%, and in the presence of nigericin, 8.1%. These values indicate a variance in measured pHi of approximately +/- 0.4 pH units, but most of this results from experimental error rather than true intercell pHi variance. The method used here is capable of detecting reduction in mean tumour pHi caused by ip glucose, but incapable of precise estimation of individual cell values. Despite these uncertainties, the results suggest that the range of pHi within B 16 tumors is small.