The existence of different strains of infectious agents involved in scrapie, a transmissible spongiform encephalopathy (TSE) of sheep and goats, remains poorly explained. These strains can, however, be differentiated by characteristics of the disease in mice and also by the molecular features of the protease-resistant prion protein (PrP res ) that accumulates into the infected tissues. For further analysis, we first transmitted the disease from brain samples of TSE-infected sheep to ovine transgenic [Tg(OvPrP4)] and to wild-type (C57BL/6) mice. We show that, as in sheep, molecular differences of PrP res detected by Western blotting can differentiate, in both ovine transgenic and wild-type mice, infection by the bovine spongiform encephalopathy (BSE) agent from most scrapie sources. Similarities of an experimental scrapie isolate (CH1641) with BSE were also likewise found following transmission in ovine transgenic mice. Secondly, we transmitted the disease to ovine transgenic mice by inoculation of brain samples of wild-type mice infected with different experimental scrapie strains (C506M3, 87V, 79A, and Chandler) or with BSE. Features of these strains in ovine transgenic mice were reminiscent of those previously described for wild-type mice, by both ratios and by molecular masses of the different PrP res glycoforms. Moreover, these studies revealed the diversity of scrapie strains and their differences with BSE according to labeling by a monoclonal antibody (P4). These data, in an experimental model expressing the prion protein of the host of natural scrapie, further suggest a genuine diversity of TSE infectious agents and emphasize its linkage to the molecular features of the abnormal prion protein.

Transgenic mice expressing the prion protein (PrP) of species affected by transmissible spongiform encephalopathies (TSEs) have recently been produced to facilitate experimental transmission of these diseases by comparison with wild-type mice. However, whilst wild-type mice have largely been described for the discrimination of different TSE strains, including differentiation of agents involved in bovine spongiform encephalopathy (BSE) and scrapie, this has been only poorly described in transgenic mice. Here, two ovine transgenic mouse lines (TgOvPrP4 and TgOvPrP59), expressing the ovine PrP (A136 R154 Q171) under control of the neuron-specific enolase promoter, were studied; they were challenged with brainstem or spinal cord from experimentally BSE-infected sheep (AA136 RR154 QQ171 and AA136 RR154 RR171 genotypes) or brainstem from cattle BSE and natural sheep scrapie. The disease was transmitted successfully from all of these sources, with a mean of approximately 300 days survival following challenge with material from two ARQ-homozygous BSE-infected sheep in TgOvPrP4 mice, whereas the survival period in mice challenged with material from the ARR-homozygous BSEinfected sheep was 423 days on average. It was shown that, in the two ovine transgenic mouse lines, the Western blot characteristics of protease-resistant PrP (PrP res ) were similar, whatever the BSE source, with a low apparent molecular mass of the unglycosylated glycoform, a poor labelling by P4 monoclonal antibody and high proportions of the diglycosylated form. With all BSE sources, but not with scrapie, florid plaques were observed in the brains of mice from both transgenic lines. These data reinforce the potential of this recently developed experimental model for the discrimination of BSE from scrapie agents. INTRODUCTIONTransmissible spongiform encephalopathies (TSEs) are fatal, neurodegenerative diseases of the central nervous system (CNS) affecting both humans (Creutzfeldt-Jakob disease; CJD) and animals, mainly sheep and goats (scrapie), deer and elk (chronic wasting disease), and cattle (bovine spongiform encephalopathy; BSE). Incubation periods are long and ultimately lead to fatal neurological clinical signs. The disease is generally associated with the accumulation of an abnormal form of a host-encoded prion protein (PrP c ) in the CNS (Prusiner, 1982). This disease-associated PrP (PrPd) differs from the cellular protein (PrP c ) in its biochemical properties, including partial resistance to proteinase K degradation (PrP res ) and insolubility in nondenaturing detergents. Prion-disease transmission between different species, if it occurs, is generally characterized by prolonged incubation periods and low susceptibility at first passage in a new host species. On subsequent subpassages in the new host species, the infectious agent generally adapts to give shorter incubation times and higher susceptibility. This illustrates the existence of a 'species barrier' phenomenon. The transmission efficiency of the disease across species largely depend...

The Tg(OvPrP4) mouse line, expressing the sheep prion protein, is a sensitive model crucial for the identification of the bovine spongiform encephalopathy agent possibly present in natural sheep spongiform encephalopathies. It was also previously demonstrated as susceptible to infection with natural scrapie isolates from sheep harbouring various genotypes. The performance of this new transgenic mouse line in scrapie strain characterization was further assessed by intracranial inoculation of five groups of Tg(OvPrP4) mice with brain homogenate of the wild type mouse-adapted scrapie strains, C506M3, 22A, 79A, 87V, or Chandler. The Tg(OvPrP4) mice were susceptible to the scrapie agent transmitted using mouse-adapted scrapie strains but not equivalently. Strains 87V and Chandler were most readily transmissible followed by 79A and C506M3. Strain 22A was the least transmissible. Clinical signs, survival data, spongiosis, and PrP(sc) distribution were also reported. These various data demonstrate the possibility of distinguishing between scrapie strains. Our findings are discussed with regard to agent strain and host factors and already demonstrate the dissimilar susceptibilities of Tg(OvPrP4) mice to the different murine strains studied, thus, reinforcing their potential use in strain typing studies.

The practice of crushing drugs is very common in geriatric units. In 2009 a first study, performed in all geriatric units of a university hospital, showed that numerous errors were made during prescription, preparation and administration. The aim of this second prospective study was to assess the impact of regional and national recommendations in the same geriatric units. A survey of 719 patients (85.3 ± 6.7 years) was performed in 2013. For each patient who received crushed drugs, we recorded the reason the drugs were crushed, pharmacological classes, galenic presentations and the technique used for preparation and administration. Results were compared to the previous study. The number of patients receiving drugs after crushing was significantly lower than in the previous study (22.9% vs. 32.3%, P < 0.001). The number of crushed drugs was lower too (594 per 165 patients vs. 966 per 224 patients (P < 0.01). The main indication for crushing drugs remained swallowing disorders. The dosage form prevented crushing in 24.9% of drugs (vs. 42.0% in 2009, P < 0.001), but the drugs generally remained crushed all together. A mortar was used less often (38.6% vs. 92.6%, P < 0.001), with preference for individual-specific cups (56.1%). Mortars were more often cleaned between each patient (56.0% vs. 11.6%). The vehicle was more often neutral (water 88.5% vs. 5.7%, P < 0.001). This second study shows that regional and national recommendations have led to an overall improvement of practices for crushing drugs. Technical improvements are still possible, in association with appropriate pharmacological studies.

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