Characterisation of a new infectious full-length cDNA clone of BVDV genotype 2 and generation of virus mutants.

Based on their genomic sequences, two genotypes of Bovine viral diarrhea virus (BVDV) can be differentiated, BVDV type 1 (BVDV-1) and BVDV type 2 (BVDV-2). The complete genomic sequence of the highly virulent BVDV-2 strain 890 was cloned as cDNA to establish the infectious cDNA clone p890FL. In vitro-synthesised full-length RNA of p890FL was transfected into bovine cells and infectious virus could be recovered (v890FL). In vitro, recombinant v890FL showed similar growth characteristics as wild type virus v890WT. However, infection experiments in calves revealed an attenuation of recombinant v890FL in comparison to the parental isolate. Both leukocytopenia and fever were less pronounced in v890FL-infected calves. Nevertheless, viremia and virus shedding were comparable between recombinant and parental BVDV 890. Furthermore, mutants with partial deletions of the genomic region encoding for the autoprotease N(pro) (p890DeltaN(pro)) or the capsid protein (p890DeltaC) were constructed and characterised. In order to generate pseudovirions, replicon p890DeltaC was efficiently trans-complemented on a helper cell line. In summary, the newly developed construct p890FL represents the first infectious full-length cDNA clone for the BVDV-2 strain 890 and offers a useful tool for further studies on the pathogenesis of BVDV-2 and the development of novel recombinant BVDV-2 specific vaccine candidates.

Intramuscular temperature responses in the human leg to two forms of cryotherapy: ice massage and ice bag.

Cryotherapy is often used to affect the muscle underlying skin and subcutaneous tissues. However, the relationship between the penetrative ability of various cryotherapy methods and treatment time is not thoroughly understood. The purpose of this study was to measure muscle temperature responses during two frequently used cryotherapy techniques. A 23-gauge hypodermic needle microprobe was inserted to one-half skin-fold thickness plus 1 cm into the medial aspect of the gastrocnemius muscle of 14 subjects. Two groups of seven subjects each were measured for temperature changes during ice bag or ice massage treatment. Each treatment consisted of a 15-minute application of the selected method. A significant difference between the two methods was observed (t = -2,157, p < or = 0.05). Ice massage achieved its lowest temperature in an average of 17.9 +/- 2.4 minutes, while ice bag reached its lowest temperature in 28.2 +/- 12.5 minutes. Ice massage appears to cool muscle more rapidly than ice bag.