Risks associated with commodity trade: transmission of viral haemorrhagic septicaemia virus (VHSV) to rainbow trout fry from VHSV-carrying tissue-homogenates

Movements of commodity fish present a potential risk of transferring pathogens. Within a study to estimate the risk from imported rainbow trout Oncorhynchus mykiss carcases, fry were exposed to tissue homogenates from market size rainbow trout infected experimentally with viral haemorrhagic septicaemia (VHS) by waterborne exposure to VHS virus (VHSV, isolate of genotype Ia). Tissues were collected from fish that showed clinical signs and from recent mortalities. Homogenates of (i) internal organs, (ii) brain/gills and (iii) muscle tissue were prepared and added to tanks holding the fry. Virus transmission occurred from all tissues tested, causing high mortality of the fry. The results underline the potential risk of introduction of VHSV through the trade of fish products.

Seroprevalence of canine leishmaniasis and American trypanosomiasis in dogs from Grenada, West Indies

Canine leishmaniasis and American trypanosomiasis (AT) are caused by related hemoflagellated parasites, Leishmania spp. and Trypanosoma cruzi, which share several common host species. Dogs are reservoirs for human infections by both pathogens. We determined the prevalence of antibodies to Leishmania spp. and T. cruzi in dogs from Grenada, West Indies. We examined 70 dog sera using the qualitative immunochromatographic dipstick tests (ICTs) based on recombinant antigens specific for visceral leishmaniasis and AT. Antibodies to visceral Leishmania were not detected in Grenadian dogs by ICT. Using the canine dipsticks for AT, antibodies to T. cruzi were determined in 3 (4.3%) of the 70 dogs. Results from this study indicate that dogs in Grenada are exposed in low levels to T. cruzi , but not to visceral Leishmania spp. at all.

Seroprevalence of Leptospira in rattus norvegicus in Grenada, West Indies

OBJECTIVE

To determine the seroprevalence of Leptospira and the serovars responsible for Leptospira exposure in rats in Grenada in order to assess rats as a reservoir host for human infection.

DESIGN AND METHODS

Rattus norvegicus rodents were collected from each of the six parishes on the island of Grenada. Serum from 237 rats was tested by the microscopic agglutination test (MAT) and an Immunoglobulin G (IgG) Enzyme-Linked Immunosorbent Assay (ELISA). Seroprevalence rates among parishes were compared using a chi-squared test of homogeneity.

RESULTS

Of the 237 serum samples tested, 64 were positive by either MAT or ELISA for an overall seroprevalence of 27%. The ELISA identified 24.5% (57/233) of the rats positive at a titer of > or = 1:160. The MAT identified 7.1% (13/183) of the rats positive at a titer of > or = 1:100. Six of the 13 MAT positive samples had antibodies to multiple serovars. The serovars identified by the MAT with the greatest frequency were from the Icterohaemorrhagiae serogroup. Two rats had antibodies for serogroup Cynopteri, the first time this serogroup has been identified in Grenada.

CONCLUSIONS

Our results for Leptospira exposure in rats in Grenada support R norvegicus as an important reservoir host for Leptospira, particularly those from the Icterohaemorrhagiae serogroup. Because this serogroup is the primary serogroup responsible for documented human exposure in Grenada, exposed rats represent a public health threat.

Gene transfer into rat brain using adenoviral vectors

Recombinant adenovirus vectors are attractive vehicles to deliver genes into the brain for the purposes of neurobiological research and for gene therapy of neurological diseases. This unit provides a comprehensive set of protocols for adenovirus vector-mediated gene transfer to the brain, including introduction of the vector into the brain by stereotaxic injection and preparation and processing of brain tissue for the evaluation of gene transfer. The potential side-effects of administering adenovirus vectors to the brain are discussed in detail. The unit also provides protocols for evaluating these side-effects (e.g., demyelination, inflammation, vector-mediated cytotoxicity, etc.). Finally, critical parameters for obtaining optimal gene transfer with minimum side-effects are presented.

Accuracy of comparing bone quality to chocolate bars for patient information purposes: observational study

OBJECTIVE

To test whether standard information for patients using Crunchie and Aero chocolate bars to explain bone health and risk of fracture is robust.

DESIGN

Observational study.

SETTING

Domestic kitchen in rural west Wales.

PARTICIPANTS

10 Crunchie bars and 10 Aero bars.

MAIN OUTCOME MEASURE

Fracture after falls from varying heights.

RESULTS

Both Crunchie and Aero bars exhibited the same T and Z scores for bone density. Crunchie bars had a lower chocolate mass index than the Aero bars. Crunchie bars are more liable to fracture.

CONCLUSIONS

Using Crunchie and Aero chocolate bars to explain bone structure to patients may be visually attractive but oversimplifies the situation.

Isolation of a cyprinid herpesvirus 2 from goldfish, Carassius auratus (L.), in the UK

Haematopoietic necrosis virus [cyprinid herpesvirus 2 (CyHV-2)] was isolated during disease outbreaks in goldfish, Carassius auratus, at an ornamental fish retail site in southern England in 2004. Signs of disease included lethargy and inappetence and were first seen after water temperatures increased from 14-15 to 19-21 degrees C. External gross pathology included pale patches on the gills and skin and internally the spleen was enlarged, often with distinctive white nodules. The most prominent histopathological changes observed were necrotic lesions in the spleen and kidney and focal patches of necrosis in the gill lamellae. Necrotic cells often contained nuclei with marginated chromatin and pale intranuclear inclusions. Ultrastructural examination of the spleen tissue revealed typical herpesvirus-like particles measuring 100 nm in diameter. The virus was isolated from extracts of gill tissue in KF-1 cells at 20 degrees C and oligonucleotide primer sets were designed based on conserved gene sequences and used to amplify viral DNA by polymerase chain reaction (PCR). The PCR assays were then used to detect the virus in DNA extracted from tissues sampled during earlier disease investigations at the retail site owner's holding facility in 2002 and 2003 and stored at -70 degrees C since then. Polymerase gene-specific PCR amplification products obtained from tissue samples and from the virus isolated in cell culture shared 100% nucleotide sequence identity with the published sequence for CyHV-2.

Arsenic in Oregon community water systems: demography matters

Recently, the maximum contaminate level (MCL) for arsenic was lowered to 10 microg/L in community water systems (CWS) throughout the United States. In this study, CWS in Oregon were assessed for the occurrence and magnitude of arsenic >10 microg/L between the effective and compliance dates for the new MCL. Ten CWS, with a combined population of 49,395, met the criteria for this study. Arsenic levels above the new MCL ranged from 11-25 microg/L. The demographic characteristics of these systems were queried and considered in the context of risk, exposure and outreach. A disproportionate percent of residents in affected CWS were of Hispanic origin (35%) compared to the statewide average (8%). Residents in these CWS had a lower median household income (20% less than the statewide average), a lower median age (32.5 vs. 36.3) and a higher percent of a second language spoken in the home besides English (34.6% vs. 12.1%) compared to the statewide census. These community characteristics have implications for exposure, risk and outreach associated with the occurrence of arsenic in drinking water. Consequently, demographic parameters are informative for risk management and communication and ultimately, beneficial to the affected public.

Mortality event in freshwater drum Aplodinotus grunniens from Lake Ontario, Canada, associated with viral haemorrhagic septicemia virus, type IV

A mortality event primarily affecting freshwater drum Aplodinotus grunniens was noted during April and May 2005 in the Bay of Quinte, Lake Ontario, Canada. A conservative estimate of the number of dead drum was approximately 100 metric tonnes. Large numbers of dead round goby Neogobius melanostomus were also seen, as well as a few muskellunge Esox masquinongy. In the drum, there was a consistent histological pattern of variably severe panvasculitis, a necrotising myocarditis, meningoencephalitis and a segmental enteritis. Moderate numbers of bullet-shaped viral particles consistent with a rhabdovirus were identified by transmission electron microscopy (TEM) in affected heart tissue. Following primary isolation from pooled tissues on fathead minnow (FHM) cells, a morphologically similar virus, approximately 165 x 60 nm in size, was visualised. Identification of the isolate as viral haemorrhagic septicemia virus (VHSV) was confirmed by enzyme immunoassay and by polymerase chain reaction. An appropriately sized product (468 bp) of the G-glycoprotein gene (nucleotides [nt] 340 to 807) was generated with RNA extracted from FHM cell supernatant. Analysis of a 360 nt partial glycoprotein gene sequence (nt 360 to 720) indicated a 96.4 to 97.2% nucleotide identity with known strains of North American (NA) VHSV. Analysis using Neighbour-joining distance methods assigned the isolate to the same lineage as the NA and Japanese isolates (Genogroup IV). However, there was sufficient sequence divergence from known NA VHSV isolates to suggest that this isolate may represent a distinct subgroup. The effects of ongoing mortality in freshwater drum and in multiple species during spring 2006 suggest that this newly recognised virus in the Great Lakes will have continued impact in the near future.

An initial evaluation of virtual reality simulation in teaching pre-clinical operative dentistry in a UK setting

The use of virtual reality (VR) training in dentistry is a recent innovation and little research has been conducted to evaluate its use. For each preclinical exercise carried out the VR software currently records a final mark for the procedure, the time taken to complete the procedure and the number of 'internal' assessments carried out by the student. The aims of this study were two fold; a critical appraisal of the software by the students using a structured feedback together with an assessment of any link between the preparation time, final mark and number of evaluations. Sixteen 2nd year undergraduate dental students spent 6 hours cutting an unlimited number of Class I cavities and Class II cavities. The final mark awarded by the VR software together with the overall preparation time and number of evaluations for each cavity were recorded. For the Class I cavity the mean mark obtained was 66.8, the mean preparation time was 12.5 mins and the mean number of evaluations was 6.7. For the Class II cavity the mean mark was 26.5, the mean preparation time was 18 mins and the mean number of evaluations was 7.0. Final marks were also stratified into quartiles (0-24, 25-49, 50- 74, 75-100). For the Class II cavity the time taken to complete the cavity and the number of evaluations made were greater for those cavities that gained a mark of 50 or more. In conclusion, this initial evaluation of the DentSim VR package was a generally positive undergraduate educational experience. The class II cavity was more difficult to cut than the class I which was reflected in the mean scores. There was also a trend towards higher marks being associated with longer preparation times and more evaluations during the preparation.

Composite Materials with Viscoelastic Stiffness Greater Than Diamond

We show that composite materials can exhibit a viscoelastic modulus (Young's modulus) that is far greater than that of either constituent. The modulus, but not the strength, of the composite was observed to be substantially greater than that of diamond. These composites contain bariumtitanate inclusions, which undergo a volume-change phase transformation if they are not constrained. In the composite, the inclusions are partially constrained by the surrounding metal matrix. The constraint stabilizes the negative bulk modulus (inverse compressibility) of the inclusions. This negative modulus arises from stored elastic energy in the inclusions, in contrast to periodic composite metamaterials that exhibit negative refraction by inertial resonant effects. Conventional composites with positive-stiffness constituents have aggregate properties bounded by a weighted average of constituent properties; their modulus cannot exceed that of the stiffest constituent.

Urotensin-II induces ear flushing in rats

BACKGROUND AND PURPOSE

While investigating the effects of systemic urotensin II (U-II), a potent vasoactive peptide acting at the UT receptor, we observed ear pinna flushing after systemic administration to conscious rats. In the present study, U-II-induced ear flushing was quantified in terms of ear pinna temperature change and potential mechanisms were explored.

EXPERIMENTAL APPROACH

U-II-induced ear flushing was quantified by measuring lateral ear pinna temperature changes and compared to that of calcitonin gene-related peptide (CGRP), a known cutaneous vasodilator. Further, the effects of a variety of pharmacological agents on U-II-induced ear flushing were explored.

KEY RESULTS

Subcutaneous injection of U-II (9 microg kg(-1))produced localized ear pinna flushing with an onset of approximately 15 min, a duration of approximately 30 min and a maximal temperature change of 9 degrees C. In contrast, CGRP caused cutaneous flushing within multiple cutaneous beds including the ear pinna with a shorter onset and greater duration than U-II. A potent UT receptor antagonist, urantide, blocked U-II-induced ear flushing but did not affect CGRP-induced ear flushing. Pretreatment with indomethacin or L-Nomega-nitroarginine methylester (L-NAME) abolished U-II-induced ear flushing. Mecamylamine or propranolol did not affect this response to U-II. Direct intracerebroventricular injection studies suggested that the ear flushing response to U-II was not mediated directly by the CNS.

CONCLUSION AND IMPLICATIONS

Our results suggest that U-II-induced ear flushing and temperature increase is mediated by peripheral activation of the UT receptor and involves prostaglandin- and nitric oxide-mediated vasodilation of small capillary beds in the rat ear pinna.

Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease ? evidence from systematic reviews of randomized controlled trials (second update, January 2006)

AIM

To update dietetic guidelines based on systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention).

METHODS

The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to January 2005 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomized controlled trials relating to diet and secondary prevention of CVD. Each review was critically appraised by at least two members of the UK Heart Health and Thoracic Dietitians Group. The quality and results of each review were discussed and summarized at a group meeting.

RESULTS

Evidence-based strategies that reduce cardiovascular events in those with CVD include reduction in saturated fat and substitution with unsaturated fats. Individuals who have suffered a myocardial infarction may also benefit from adopting a Mediterranean type diet and increasing intake of omega 3 fats, but it is not clear whether they are beneficial for all patients with CVD. There is no systematic review evidence to support the use of antioxidant vitamins supplements, low glycaemic index diets, or homocysteine lowering therapies in this group.

CONCLUSION

There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.

31 FULL-TERM AND LIVE RABBIT CLONES PRODUCED BY SOMATIC CELL NUCLEAR TRANSFER

Transgenic/knockout (KO) rabbits can serve as an excellent animal model for human cardiovascular diseases (CVD) and other diseases. However, the production of transgenic/KO rabbits is hindered by low efficiency of traditional DNA microinjection and the unavailability of embryonic stem cell lines. An alternative approach is to produce transgenic/KO rabbits by somatic cell nuclear transfer (SCNT) using genetically modified somatic cells as nuclear donors. Our initial objective of the study was to prove the feasibility of cloning rabbits by SCNT because rabbit is a difficult species to be cloned. Rabbit oocytes were flushed from the oviducts of superovulated donors treated with the regime of follicle-stimulating hormone (FSH) and human choriani gonadotropin (hCG). Cumulus cells were then denuded from the oocytes by incubation in 0.5% hyaluronidase and pipetting. Oocyte enucleation was conducted in M199 + 10% fetal bovine serum (FBS) and confirmed by fluorescence microscopy. Cumulus cells used for nuclear donors were prepared from fresh cumulus-oocytes complexes. The donor nucleus was transferred into a recipient oocyte by either cell fusion or direct nuclear injection method. In the cell fusion method, a small donor cell with the diameter approximately 15–19 µm was transferred into the perivitelline space of an enucleated oocyte; subsequently the somatic cell-cytoplast pair was fused by applying three direct current pulses at 3.2 kV/cm for a duration of 20 µs/pulse. In the direct nuclear injection method, a mechanically lysed donor cell was injected into oocyte cytoplasm with the aid of a piezo-drill system. Fused embryos or injected oocytes were activated by the same electrical stimulation regime described above, and subsequently cultured in M199 + 10% FBS containing 2.0 mM 6-dimethylaminopurine (DMAP) and 5 µg/mL cycloheximide for 2 h. For the in vitro study, cloned embryos were cultured in B2 medium plus 2.5% FBS for 5 days (initiation of activation = day 0) at 38.5°C in 5% CO2 humidified air. For the in vivo study, cloned embryos were cultured for 20–22 h in vitro before transfer into pseudopregnant rabbit recipients. Pregnancy was monitored by palpation and/or ultrasound on Days 14–16 post embryo transfer (ET). The results (Table 1) show that the donor nuclei-introducing rate was higher with nuclear direct injection than with the cell fusion method (P < 0.05). There were no significant differences among subsequent cleavage and development to morula and blastocysts between both methods, although the development rates of cloned embryos via electrically mediated fusion were higher than those derived from the injection group. One recipient in the injection group (1/6, 17%) and six recipients in the fusion group (6/16, 38%) were diagnosed as pregnant. From the fusion group, one full-term but stillborn and one live and healthy clone rabbit were delivered on Days 33 and 31 post-ET, respectively. To our knowledge, this is the second report of full term development of cloned rabbit by somatic nuclear transfer cloning. Our further study is to clone live rabbit offspring with modified transgenic/KO somatic cell lines. Table 1. In vitro development of rabbit cloned embryos with cumulus cells as nuclear donors This work was supported by NIH/NCRR-SBIR grant: 1R43RR020261–11.