Neuronal inclusions resembling Negri bodies in the thalamus of a red kangaroo (Macropus rufus).

Eosinophilic intracytoplasmic neuronal inclusions resembling Negri bodies, but not associated with lyssaviral infection, were detected in the ventrolateral thalamus of a young-adult, male red kangaroo (Macropus rufus). Similar neuronal inclusions, also with a regional distribution in the brain, have been reported as an incidental, possibly age-related finding in other animal species.

Outcome of challenging HIV case consultations provided via teleconference by the Clinician Consultation Center to the Federal Bureau of Prisons.

OBJECTIVES: To describe the collaboration and prospective outcome of challenging human immunodeficiency virus (HIV) cases presented by Board of Prisons (BOP) pharmacists in consultation with Clinician Consultation Center (CCC) clinical pharmacists and physicians to improve correctional patient care. SETTING: Federal correctional facilities. PRACTICE DESCRIPTION: Pharmacists improve care of incarcerated persons infected with HIV. PRACTICE INNOVATION: Pharmacists evaluate, implement, and provide successful oversight of HIV/hepatitis C virus (HCV) care. EVALUATION: Retrospective review of the clinical outcomes of HIV and HCV coinfected cases implemented by BOP pharmacists following CCC clinical consultations from 2010 through 2012. RESULTS: Most cases focused on selecting optimal antiretroviral therapy (ART) regimens in patients experiencing treatment failure by interpreting resistance tests, limiting ART toxicity, identifying adherence strategies, and managing HIV/HCV coinfection. In 32 of the 34 cases presented, 87.5% (28/32) of CCC recommendations were implemented, resulting in 89% of those patients (25/28) achieving optimal virologic or clinical outcome. Complete virologic suppression occurred in 64% (18/28), and significant viral load reductions in 25% (7/28) of the cases. No changes occurred in 2 patients, and data were not available in 2 others lost to follow-up. BOP participation has increased since its inception from 6 to 12-15 pharmacists per call. Discussions also included updates in antiretroviral guidelines, screening and management of patients coinfected with HIV and HCV, and implications for BOP guidelines. CONCLUSION: BOP clinical consultant pharmacists can successfully implement CCC recommendations to achieve desired clinical outcomes. Consultations and educational efforts from CCC experts assist BOP pharmacists in ensuring excellence in management of complex HIV/HCV issues and medication regimens to achieve desired outcomes. CCC collaboration and BOP pharmacist involvement have improved patient care. Using a team approach to include BOP clinical pharmacists and obtaining expert opinion in management of other chronic illnesses may be a model that can be considered to improve correctional care.

Highly Pathogenic Avian Influenza (H5N1) Virus in Feathers.

H5N1 highly pathogenic avian influenza (HPAI) virus causes high mortality of infected birds, with infection in multiple organs, including in feathers. Feathers have been proposed as samples for diagnosis of HPAI infection in birds, and this study is part of a broader investigation validating the use of feathers for diagnostic purposes. To understand and characterize the morphological basis for feather infection, sections from 7 different skin tracts of ducks and chickens infected with 3 different clades of H5N1 HPAI virus from Indonesia and Vietnam were examined histologically. Results showed that in ducks, lesions and viral antigen were mainly detected in the epidermis of feathers and follicles, whereas in chickens, they were mostly found in the dermis of these structures. Abundant viral antigen was found in nearly all the feathers examined from chickens, and there was no apparent difference between virus isolates or skin tracts in the proportion of feathers that were antigen positive. By immunohistochemistry, the majority of feathers from most skin tracts from ducks infected with a Vietnamese H5N1 HPAI virus contained abundant levels of viral antigen, while few feathers were antigen positive from ducks infected with 2 Indonesian viruses. These results support and inform the use of feathers for diagnostic detection of H5N1 HPAI virus in birds.

Atypical scrapie in Australia.

BACKGROUND: Since its initial detection in Norway in 1998, atypical scrapie ('atypical/Nor98 scrapie') has been reported in sheep in the majority of European countries (including in regions free of classical scrapie) and in the Falkland Islands, the USA, Canada, New Zealand and Australia. CASE SERIES: The diagnosis in Australia of atypical scrapie in four Merino and one Merino-cross sheep showing clinical signs of neurological disease was based on the detection of grey matter neuropil vacuolation (spongiform change) in the brain (particularly in the molecular layer of the cerebellar cortex) and associated abnormal prion protein (PrPSc ) deposition in both grey and white matter. Changes were minimal in the caudal brainstem, the predilection site for lesions of classical scrapie. CONCLUSION: The distinctive lesion profile of atypical scrapie in these five sheep highlights the diagnostic importance of routine histological evaluation of the cerebellum for evidence of neuropil vacuolation and associated PrPSc deposition in adult sheep with suspected neurological disease.

Federal Bureau of Prisons clinical pharmacy program improves patient A1C.

OBJECTIVE: The Federal Bureau of Prisons (BOP) currently has over 13,000 patients with diabetes and has placed an emphasis on preventing and delaying the onset or progression of diabetes-related complications. In an ongoing effort to improve patient outcomes, BOP has implemented a nationwide, dynamic system of pharmacist-delivered patient care services via pharmacist clinicians working under the auspices of a physician-pharmacist collaborative practice agreement (CPA). SETTING: The BOP Clinical Pharmacy Workgroup targets improved patient outcomes via oversight and support of institution pharmacist clinicians and physicians in establishing and maintaining physician-pharmacist CPAs. A primary emphasis is diabetes and the pharmacist-run clinic clinical outcomes data are presented. PRACTICE INNOVATION: Seventy (nearly one-half) of eligible BOP pharmacists at 37 institutions offer pharmacist-delivered patient care services via an approved CPA. In total, BOP has 111 active physician-pharmacist CPAs. MAIN OUTCOME MEASURES: Pharmacist-run diabetes clinic outcomes from 5 institutions have been reported to date. A total of 126 patients were enrolled. Patient's hemoglobin A1C, blood pressure, and LDL cholesterol level are measured before (i.e., when accepted in the diabetes clinic) and after pharmacist-delivered care has been provided. The pharmacist-run diabetes clinics reported an average baseline A1C of 10.6% and produced an average outcome decrease in A1C of 2.3% from baseline. RESULTS: Specific pharmacist clinic interventions found to have the greatest impact are: 1) timely medication adjustment when indicated to help patients meet outcome goals; and 2) timely follow-up after a change in therapy is made (often within 1-2 weeks) with continued medication adjustment when indicated until outcome goal is achieved. CONCLUSION: BOP pharmacists have become respected and trusted clinicians within the team medicine model. As demonstrated by the pharmacist-run diabetes clinic outcomes, pharmacist clinicians are a valued link to the improvement of patient outcomes in BOP.

Morbillivirus-associated unusual mortality event in South Australian bottlenose dolphins is largest reported for the Southern Hemisphere.

Cases of morbillivirus have been recorded in the Southern Hemisphere but have not been linked to significant marine mammal mortality. Post-mortems were conducted on 58 carcasses (44 Indo-Pacific bottlenose dolphins, two common bottlenose dolphins, 12 short-beaked common dolphins) from South Australia during 2005-2013, including an unusual mortality event (UME) in St Vincent Gulf Bioregion (SVG) during 2013. Diagnostic pathology, circumstance of death, body condition, age and stomach contents were documented for Indo-Pacific bottlenose dolphins. At least 50 dolphins died during the UME, 41 were Indo-Pacific bottlenose dolphins and most were young. The UME lasted about seven months and had two peaks, the first being the largest. Effect on the population is unknown. Diagnostic testing for morbillivirus was conducted on 57 carcasses, with evidence for infection in all species during 2011-2013. All tested UME bottlenose dolphins were positive for cetacean morbillivirus (CeMV), and the pathology included interstitial pneumonia, lymphoid depletion and syncytia. Concurrent pathologies, including lung parasite and fungal infections, and severe cutaneous bruising were observed in many dolphins. The event coincided with elevated water temperatures, a diatom bloom and significant fish die-offs. We conclude that the cause for the UME was multifactorial and that CeMV was a major contributor.

Increased sensitivity to platinum drugs of cancer cells with acquired resistance to trabectedin.

BACKGROUND: In order to investigate the mechanisms of acquired resistance to trabectedin, trabectedin-resistant human myxoid liposarcoma (402-91/T) and ovarian carcinoma (A2780/T) cell lines were derived and characterised in vitro and in vivo. METHODS: Resistant cell lines were obtained by repeated exposures to trabectedin. Characterisation was performed by evaluating drug sensitivity, cell cycle perturbations, DNA damage and DNA repair protein expression. In vivo experiments were performed on A2780 and A2780/T xenografts. RESULTS: 402-91/T and A2780/T cells were six-fold resistant to trabectedin compared with parental cells. Resistant cells were found to be hypersensitive to UV light and did not express specific proteins involved in the nucleotide excision repair (NER) pathway: XPF and ERCC1 in 402-91/T and XPG in A2780/T. NER deficiency in trabectedin-resistant cells was associated with the absence of a G2/M arrest induced by trabectedin and with enhanced sensitivity (two-fold) to platinum drugs. In A2780/T, this collateral sensitivity, confirmed in vivo, was associated with an increased formation of DNA interstrand crosslinks. CONCLUSIONS: Our finding that resistance to trabectedin is associated with the loss of NER function, with a consequent increased sensitivity to platinum drugs, provides the rational for sequential use of these drugs in patients who have acquired resistance to trabectedin.

p53 protein aggregation promotes platinum resistance in ovarian cancer.

High-grade serous ovarian carcinoma (HGSOC), the most lethal gynecological cancer, often leads to chemoresistant diseases. The p53 protein is a key transcriptional factor regulating cellular homeostasis. A majority of HGSOCs have inactive p53 because of genetic mutations. However, genetic mutation is not the only cause of p53 inactivation. The aggregation of p53 protein has been discovered in different types of cancers and may be responsible for impairing the normal transcriptional activation and pro-apoptotic functions of p53. We demonstrated that in a unique population of HGSOC cancer cells with cancer stem cell properties, p53 protein aggregation is associated with p53 inactivation and platinum resistance. When these cancer stem cells differentiated into their chemosensitive progeny, they lost tumor-initiating capacity and p53 aggregates. In addition to the association of p53 aggregation and chemoresistance in HGSOC cells, we further demonstrated that the overexpression of a p53-positive regulator, p14ARF, inhibited MDM2-mediated p53 degradation and led to the imbalance of p53 turnover that promoted the formation of p53 aggregates. With in vitro and in vivo models, we demonstrated that the inhibition of p14ARF could suppress p53 aggregation and sensitize cancer cells to platinum treatment. Moreover, by two-dimensional gel electrophoresis and mass spectrometry we discovered that the aggregated p53 may function uniquely by interacting with proteins that are critical for cancer cell survival and tumor progression. Our findings help us understand the poor chemoresponse of a subset of HGSOC patients and suggest p53 aggregation as a new marker for chemoresistance. Our findings also suggest that inhibiting p53 aggregation can reactivate p53 pro-apoptotic function. Therefore, p53 aggregation is a potential therapeutic target for reversing chemoresistance. This is paramount for improving ovarian cancer patients' responses to chemotherapy, and thus increasing their survival rate.

Federal Bureau of Prisons HIV consultant pharmacist monitoring and advisory program.

OBJECTIVE: To present outcomes resulting from the implementation of a pharmacist-run human immunodeficiency virus (HIV) medication management model. SETTING: Federal Bureau of Prisons (BOP) from December 2004 to December 2009. PRACTICE DESCRIPTION: The BOP instituted the National HIV Clinical Pharmacist Consultant (NHCPC) program in December 2004. NHCPCs monitor and provide guidance as to the appropriateness of antiretroviral therapy (ART) throughout the BOP. They also serve as readily accessible resources for all BOP providers, having the training and expertise necessary to affect positive patient outcomes. NHCPCs were provided intensive training through a Johns Hopkins University HIV/acquired immunodeficiency syndrome pharmacotherapy traineeship administered by the American Society of Consultant Pharmacists and have AAHIVE (HIV Expert) credentialing. PRACTICE INNOVATION: NHCPCs monitor HIV therapy and patient outcomes via BOP electronic medical records. MAIN OUTCOME MEASURES: The vision for this program encompasses an overall healthier BOP HIV patient population being treated in accordance with current Department of Health & Human Services guidelines. Specifically, all patients taking ART have the goals of (1) achieving undetectable viral loads (≥70%), (2) maintaining CD4 T-cell counts of 200 cells/mm3 or more (≥70%), and (3) taking at least 90% of prescribed doses. RESULTS: From April 2004 to December 2009, the overall percentage of BOP patients with undetectable viral loads increased from 32% to 66%. As of December 2009, 76% of patients receiving ART achieved CD4 counts of 200 cells/mm3 or greater and 73% were taking 90% or more of prescribed doses. CONCLUSION: The NHCPC program lends credence to the value of pharmacists in improving patient outcomes.

Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus).

A juvenile offshore bottlenose dolphin (Tursiops truncatus) was found stranded with neurological signs and unable to swim or float unassisted. It subsequently died, succumbing to a combination of severe pneumonia and encephalitis. Morbillivirus serum neutralisation test serology was positive (titre 1:16) for cetacean morbillivirus and negative for both phocine distemper virus and canine distemper virus. There was concurrent thymic and lymph node lymphoid depletion and necrosis, together with intranuclear and intracytoplasmic acidophilic viral inclusion bodies and multinucleate syncytia within multiple organs. Paramyxovirus capsids were identified in lung sections via electron microscopy and morbillivirus antigen was demonstrated within sections of lung, thymus and brain by immunohistochemistry. Reverse transcription-polymerase chain reaction for morbillivirus nucleoprotein (N) and phosphoprotein (P) genes were positive and phylogenetic gene product sequence analysis revealed 98% and 94% sequence identity to dolphin morbillivirus, respectively. To the authors' knowledge, this is the first report of a cetacean mortality due to morbillivirus infection occurring in the southern hemisphere. Morbillivirus infection should be included in the differential diagnosis of stranded live or dead cetaceans in Australian waters, particularly if animals display neurological signs.

A diverse family of novel peptide toxins from an unusual cone snail, Conus californicus.

Diversity among Conus toxins mirrors the high species diversity in the Indo-Pacific region, and evolution of both is thought to stem from feeding-niche specialization derived from intra-generic competition. This study focuses on Conus californicus, a phylogenetic outlier endemic to the temperate northeast Pacific. Essentially free of congeneric competitors, it preys on a wider variety of organisms than any other cone snail. Using molecular cloning of cDNAs and mass spectrometry, we examined peptides isolated from venom ducts to elucidate the sequences and post-translational modifications of two eight-cysteine toxins (cal12a and cal12b of type 12 framework) that block voltage-gated Na(+) channels. Based on homology of leader sequence and mode of action, these toxins are related to the O-superfamily, but differ significantly from other members of that group. Six of the eight cysteine residues constitute the canonical framework of O-members, but two additional cysteine residues in the N-terminal region define an O+2 classification within the O-superfamily. Fifteen putative variants of Cal12.1 toxins have been identified by mRNAs that differ primarily in two short hypervariable regions and have been grouped into three subtypes (Cal12.1.1-3). This unique modular variation has not been described for other Conus toxins and suggests recombination as a diversity-generating mechanism. We propose that these toxin isoforms show specificity for similar molecular targets (Na(+) channels) in the many species preyed on by C. californicus and that individualistic utilization of specific toxin isoforms may involve control of gene expression.

Experimental studies of the role of the little raven (Corvus mellori) in surveillance for West Nile virus in Australia.

OBJECTIVE: To study the potential role of an Australian corvid, the little raven (Corvus mellori), in the surveillance for exotic West Nile virus (WNV) in Australia. METHOD: In a series of trials, little ravens were infected with WNV (strain 4132 New York 1999) and Kunjin virus (strain K42886) by the intramuscular route. They were observed for 20 days during which blood and swab samples were taken for virus isolation. Tissue samples were taken from ravens humanely killed during the acute infection period, and at the termination of the trials, for virus isolation, histopathology and immunohistochemistry. RESULTS: Ravens infected with WNV became mildly ill, but all recovered and seroconverted. Blood virus titres peaked around 3 to 4 days after inoculation at levels between 10(3.0) to 10(7.5) plaque forming units/mL. Virus or viral antigen was detected in spleen, liver, lung, kidney, intestine, testis and ovary by virus isolation and/or immunohistochemistry. WNV was detected in oral and cloacal swabs from 2 to 7 days post inoculation. The molecular and pathogenic characteristics of the inocula were consistent with them being of high virulence, as expected for this isolate. Ravens infected with Kunjin virus developed viraemia and seroconverted, although they did not develop disease. CONCLUSIONS: Little ravens do not develop severe disease in response to virulent WNV infection and for this reason may not be important sentinel hosts in the event of an outbreak of WNV, as in North America. However, as they have relatively high viraemias, they may be able to support virus cycles.

Maternal IgM anti-D, borderline foetal Doppler middle cerebral artery velocities and absent neonatal haemolysis.

Anti-D was detected for the first time at 36 weeks gestation in a group A RhD-negative primigravida without prior sensitizing events or anti-D administration. Simultaneously, foetal ultrasound showed middle cerebral artery maximum velocity (MCA V(max)) at the 95th centile but no hydrops. Labour was induced at 37 weeks. Although neonatal anaemia was anticipated, the baby, who was group O RhD-positive, was born with a normal haemoglobin and negative direct antiglobulin test and antibody screen. Retrospectively, the maternal anti-D proved to be exclusively immunoglobulin M (IgM), which does not cross the placenta. Foetal Doppler MCA V(max) measurements can give false positive results especially late in the third trimester. Thus, antibody class, especially in first pregnancies without prior sensitizing events, and the timing of foetal Doppler MCA velocity measurements should be considered when evaluating the likelihood and severity of haemolytic disease of the foetus and newborn.

In vivo cartilage contact deformation in the healthy human tibiofemoral joint.

OBJECTIVES: In vivo cartilage contact deformation is instrumental for understanding human joint function and degeneration. This study measured the total deformation of contacting articular cartilage in the human tibiofemoral joint during in vivo weight-bearing flexion. METHODS: Eleven healthy knees were magnetic resonance (MR) scanned and imaged with a dual fluoroscopic system while the subject performed a weight-bearing single-leg lunge. The tibia, femur and associated articulating cartilage were constructed from the MR images and combined with the dual fluoroscopic images to determine in vivo cartilage contact deformation from full extension to 120 degrees of flexion. RESULTS: In both compartments, minimum peak compartmental contact deformation occurred at 30 degrees of flexion (24 +/- 6% medial, 17 +/- 7% lateral) and maximum peak compartmental deformation occurred at 120 degrees of flexion (30 +/- 13% medial, 30 +/- 10% lateral) during the weight-bearing flexion from full extension to 120 degrees. Average medial contact areas and peak contact deformations were significantly greater than lateral compartment values (P < 0.05). In addition, cartilage thickness in regions of contact was on average 1.4- and 1.1-times thicker than the average thickness of the tibial and femoral cartilage surfaces, respectively (P < 0.05). CONCLUSIONS: These data may provide base-line knowledge for investigating the effects of various knee injuries on joint contact biomechanics and the aetiology of cartilage degeneration.

Development of a TaqMan PCR assay for the detection of Trypanosoma evansi, the agent of surra.

A TaqMan PCR assay was developed for the detection of Trypanosoma evansi. The assay targets the internal transcribed spacer 1 (ITS-1) region of rRNA. The ITS-1 region of eleven strains of T. evansi from widely separated geographical regions were sequenced and alignments compared. Primers and probe for the test were designed from these sequence data. The assay was tested using blood from infected rats and was found to be sensitive, detecting less than one genomic equivalent of T. evansi. The assay has been tested against 10 different species of trypanosomes found in native animals in Australia and did not detect any of these trypanosome species. Time course experiments using rats infected with T. evansi were performed to compare the TaqMan assay with the Haematocrit centrifugation test (HCT) and the mouse inoculation (MI) assay. The assay was more sensitive than the HCT but not as sensitive as the MI. The TaqMan assay has the ability to rapidly detect T. evansi and determine the number of organisms present in a blood sample from an infected animal. This is the first time a TaqMan assay has been developed for the detection of T. evansi.

Viral morphogenesis and morphological changes in human neuronal cells following Tioman and Menangle virus infection.

Tioman virus (TioPV) and Menangle virus (MenPV) are two antigenically and genetically related paramyxoviruses (genus: Rubulavirus, family: Paramyxoviridae) isolated from Peninsular Malaysia (2001) and Australia (1997), respectively. Both viruses are potential zoonotic agents. In the present study, the infectivity, growth kinetics, morphology and morphogenesis of these two paramyxoviruses in a human neuronal cell (SK-N-SH) line were investigated. Sub-confluent SK-N-SH cells were infected with TioPV and MenPV at similar multiplicity of infection. These cells were examined by conventional and immunoelectron microscopy, and virus titres in the supernatants were assayed. Syncytia were observed for both infections in SK-N-SH cells and were more pronounced during the early stages of TioPV infection. The TioPV titre increased consistently (10(1)) every 12 h after infection. In MenPV-infected cells, cellular material was frequently observed within budding virions, and microfilaments and microtubules were abundant. Viral budding was common, and extracellular MenPVs tended to be more pleomorphic compared to TioPVs, which appeared to be more spherical in appearance. The MenPV cytoplasmic viral inclusion appeared to be comparatively smaller, loose and interspersed with randomly scattered circle-like particles, whereas huge tubule-like cytoplasmic inclusions were observed in TioPV-infected cells. Both viruses also displayed different cellular pathology in the SK-N-SH cells. The intracellular ultrastructural characteristics of these two viruses in infected neuronal cells may allow them to be differentiated by electron microscopy.

Infection trials in pigs with a human isolate of Brucella ( isolate 02/611 'marine mammal type' ).

AIM: To determine if pigs could support infection of a human Brucella isolate (Brucella 02/611) from New Zealand, and to study seroconversion to this isolate using a competitive ELISA. METHODS: Ten weaner piglets were challenged with 4.8 x 10(8) cfu of organisms by the oral and ocular routes. Culture was attempted on blood samples taken prior to challenge, and 4, 7, 9, 11, 14, 21 and 28 days post-challenge, and on tissue samples taken at the termination of the trial, 1 month after challenge. Sera were analysed for antibody using an ELISA. For reference comparison, similar trials were conducted in two pigs using an isolate of Brucella suis biovar 1, and two pigs using an isolate of B. suis biovar 3. RESULTS: Brucella 02/611 organisms were re-isolated from one lymph node each from three pigs; all other samples were negative. Low and transient antibody titres were detected using a competitive ELISA in three pigs, two of which were culture negative. Organisms of B. suis reference strains were re-isolated from multiple samples from each of the four animals. CONCLUSION: Brucella 02/611 does not seem to replicate readily in pigs. It is unlikely that pigs were the original maintenance hosts for Brucella 02/611.

Towards an empirical model of performance enhancing supplement use: a pilot study among high performance UK athletes.

This paper addressed a gap in the literature of empirically derived models of performance enhancing supplement use by developing a demographic and psychosocially based model of athlete supplement use. Selected questions were used from a larger survey conducted by UK Sport into British athletes' experiences, knowledge, attitudes and opinions in relation to anti-doping activities. Forward conditional step wise logistic regression was employed on data from n=757 athletes to develop a model that discriminated supplement non-users from users. The model identified that British athletes most likely to use supplements were younger (under 23) males who were more likely to see doping as a problem in their sport and were more knowledgeable about testing procedures than their non-user counterparts. Post hoc analysis reinforced that non-users saw doping as less of a problem in their sport and were less knowledgeable about drug testing procedures relative to those using supplements. The pattern of results indicated gender-specific interventions on supplement use for young male athletes may yield significant benefits. The relationship between supplement use and perception of a doping problem suggested more work is needed to understand supplement use culture within sports. The relationship between knowledge of testing procedures and supplement use suggested further research is needed to see whether this is a positive or negative effect of detection-based doping deterrence activity.

Investigation of prion removal/inactivation from chromatographic gel.

BACKGROUND AND OBJECTIVES: Concerns about the potential for prions to be retained on chromatography gels during the manufacture of plasma products prompted development of an investigational strategy for detecting infectious prions bound to gels. The objective was to firstly examine methods of implanting gels intracerebrally (IC) in mice, then to examine prion cleaning from a scaled-down version of the DEAE Sepharose column used in a production process to fractionate immunoglobulins and albumin from human plasma. MATERIALS AND METHODS: The study consisted of two parts: (i) the pathophysiological impact by IC inoculation of ground gel beads was compared to whole gel beads; (ii) the feedstreams to two DEAE Sepharose columns were spiked with scrapie ME7. One column was subjected to the protein loading and elution portions of the chromatography cycle. The other column was subjected to the full cycle of protein loading and elution, followed by regeneration with 0.5 m NaCl, 1 m NaOH and solvent/detergent washes. The gels were unpacked and bioassayed by IC implantation in mice to quantify infectivity. RESULTS: IC inoculation of ground gel beads resulted in unacceptably high pathological impact in the mice whereas whole gel bead inoculation resulted in a reduced affect. Accordingly, the whole bead model system was used to assess prion removal/inactivation from chromatography gels at the pre- and postcleaning stage of the chromatography cycle. Infectious prions were detected on the DEAE Sepharose prior to the cleaning step; however, the gel cleaning cycle reduced infectivity by a log reduction factor (LRF) of > or = 2.75, thus reducing infectivity by bioassay to below detectable limits. CONCLUSIONS: A model system for assessment of prion inactivation/removal from chromatography gels has been established. Spiked prion infectivity does bind to DEAE Sepharose gel; however, the cleaning cycle removed infectivity to levels below that detectable by bioassay.