Cardiovascular responses of three salmonid species affected with amoebic gill disease (AGD)

The cardiovascular effects of amoebic gill disease (AGD) were investigated immediately following surgery in three salmonid species; Atlantic salmon (Salmo salar L.), brown trout (Salmo trutta L.) and rainbow trout (Oncorhynchus mykiss Walbaum). Fish, both naïve (control) and infected (AGD-affected) of each species, were fitted with dorsal aorta catheters and cardiac flow probes. Cardiac output and dorsal aortic pressures were then continuously measured over a 6-h period following surgery. Results showed that Atlantic salmon, brown trout and rainbow trout displayed similar dorsal aortic pressure, cardiac output, and systemic vascular resistance (mean dorsal aotic pressure divided by cardiac output) values. However, the only significant differences relating to disease status i.e. infected or control, were found in Atlantic salmon. Although no significant differences were seen in dorsal aortic pressure values, AGD-affected salmon displayed significantly elevated systemic vascular resistance at 4 and 6 h post surgery. Cardiac output was also approximately 35% lower in AGD-affected salmon compared to the non-affected control counterparts. These results comparatively examine cardiac function in response to AGD across three salmonid species and highlight species-specific cardiovascular responses that occur in association with disease. It is suggested that the apparent cardiac dysfunction seen in AGD-affected Atlantic salmon could, under stressful conditions, become exacerbated. Cardiac failure is therefore suggested to be a possible physiological mechanism by which AGD causes or contributes to mortality in Atlantic salmon.

Experience of targeting subsidies on insecticide-treated nets: what do we know and what are the knowledge gaps?

Widespread coverage of vulnerable populations with insecticide-treated nets (ITNs) constitutes an important component of the Roll Back Malaria (RBM) strategy to control malaria. The Abuja Targets call for 60% coverage of children under 5 years of age and pregnant women by 2005; but current coverage in Africa is unacceptably low. The RBM 'Strategic Framework for Coordinated National Action in Scaling-up Insecticide-Treated Netting Programmes in Africa' promotes coordinated national action and advocates sustained public provision of targeted subsidies to maximise public health benefits, alongside support and stimulation of the private sector. Several countries have already planned or initiated targeted subsidy schemes either on a pilot scale or on a national scale, and have valuable experience which can inform future interventions. The WHO RBM 'Workshop on mapping models for delivering ITNs through targeted subsidies' held in Zambia in 2003 provided an opportunity to share and document these country experiences. This paper brings together experiences presented at the workshop with other information on experiences of targeting subsidies on ITNs, net treatment kits and retreatment services (ITN products) in order to describe alternative approaches, highlight their similarities and differences, outline lessons learnt, and identify gaps in knowledge. We find that while there is a growing body of knowledge on different approaches to targeting ITN subsidies, there are significant gaps in knowledge in crucial areas. Key questions regarding how best to target, how much it will cost and what outcomes (levels of coverage) to expect remain unanswered. High quality, well-funded monitoring and evaluation of alternative approaches to targeting ITN subsidies is vital to develop a knowledge base so that countries can design and implement effective strategies to target ITN subsidies.

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).

Cerebrospinal fluid and serum concentrations of beta-trace protein during pregnancy

We conducted a prospective observational study among a cohort of 40 term parturients undergoing spinal anaesthesia for elective Caesarean section, to determine the concentration of beta-trace protein in cerebrospinal fluid (CSF) and serum. Serum and CSF samples, taken at the time of dural puncture, were assayed by nephelometry. The mean serum beta-trace protein concentration was 0.39 mg.l(-1) and the mean CSF concentration was 27.9 mg.l(-1), giving a mean ratio of CSF to serum concentration of 76. This ratio is higher than that published for non-pregnant females and for males because of both a higher mean CSF and a lower mean serum beta-trace protein concentration. The concentration correlated positively with both serum creatinine and gestational age. If these concentrations are used to estimate the normal range, we propose that the nephelometric measurement of beta-trace protein might prove a useful diagnostic test for cerebrospinal fluid-cutaneous fistula in parturients.

021. Current progress into testis cell transfer between cattle breeds

Male germline cell transfer has produced offspring in mice (Brinster and Zimmermann 1994). Recently the first livestock animal, a goat, was produced (Honaramooz et al. 2003), while early results in cattle are promising (Oatley et al. 2002; Izadyar et al. 2003). There is an opportunity to develop this technology for the beef industry by transferring male germ line stem cells between breeds to improve the genetics of extensive Australian beef herds. This project is a part of the CSIRO National Research Flagship program that combines expertise and facilities in divisions with complementary expertise at Monash University and the University of Sydney. The environmental constraints of Northern Australia dictate that Brahman type animals show far better survival than Bos taurus cattle, although the carcass value of Brahmans is lower than Bos taurus animals. Artificial insemination is impractical in Northern Australia and thus we aim to develop testis cell transfer technique in cattle to permit Brahman bulls to deliver semen from elite Bos taurus or composite bulls, thereby significantly increasing the growth rate, yield and meat quality of the northern beef herd. Experiments using cattle were performed to determine the applicability of techniques used in the mouse. Initial proof of concept has been achieved that germ cell transfer can result in the donor cells successfully colonizing areas of recipient testis. The viability of isolated testis cells following short term (24 h) culture has been demonstrated through transfer into recipient calves. We have completed >50 male germ cell transfers into recipient calves, using ultrasonographic guided injection into the rete testis. Success of this procedure has been demonstrated by persistence of PKH26 dyed donor cells in the seminiferous tubules of a majority of recipients >2 months after transfer. These recipient male calves have not been depleted of their endogenous spermatogonial populations and we thus expect the efficiency of the procedure to increase as depletion procedures (ongoing) are established. Concurrent with these developments has been research into large scale culture of male germ line stem cells to provide large numbers of stem cells for transplant. Culture of testis cell suspensions has demonstrated survival of enriched testis cells under varying media and culture conditions. Initial passaging of testis cell colonies has revealed mixed cell populations (immunohistochemistry positive for spermatogonia and somatic cells). Further studies will aim to demonstrate that these cultured donor cells are able to undergo spermatogenesis in the recipient animals.

107 INITIAL RESULTS FROM MALE GERM CELL TRANSFER BETWEEN CATTLE BREEDS

Male germline cell transfer has produced offspring in mice (Brinster & Zimmerman 1994 PNAS 91, 11 298–11 302). Recently the first livestock animal, a goat, was produced (Honaramooz et al. 2003 Mol. Reprod. Dev. 64 422–64 428.), and early results in cattle are promising (Izadyar et al. 2003 Reproduction 126, 765–774; Oatley et al. 2002 J. Anim. Sci. 80, 1925–1931). We have assessed the outcome of male germ cell transfer between breeds of cattle and the efficacy of two vital dyes as markers of donor cells following transfer. Testis cells from three Bos taurus (Angus) bull calves were used as donor cells to transfer into six Bos indicus cross (predominantly Brahman bloodline) bull calves. Each of the calves was prepubertal and aged between 5 and 7 months. The calves were castrated; then a single-cell suspension of testis cells was prepared enzymatically using collagenase, DNAase, and trypsin. Prior to transfer into the recipient calves, the testis cell suspensions were dyed with one of two long-term vital dyes (PKH26 or CFDA). Approximately 300 million cells were injected into the rete of each testis under ultrasonographic guidance. In four of the six recipients, CFDA was injected into one testis and PKH26 into the other. These four recipients were castrated at 2, 4, 6, and 8 weeks after transfer. The other two recipients received either CFDA or PKH26 into both testes and were castrated at 8 weeks after transfer. Following castration, PKH positive donor cells were found in freshly isolated tubules of each of the five recipients that received PKH-dyed cells, while no CFDA-positive donor cells were conclusively identified in any of the recipients. In the freshly isolated tubules, clumps of PKH-positive donor cells were observed, which indicated either cell division or substantial local colonization of certain areas of the tubules. Frozen sections were used to further localize the PKH positive donor cells. Positive cells were located on the seminiferous tubule basement membrane, which indicates these cells had successfully migrated from the tubule lumen and were likely to be spermatogonia. There was variation in the amount of fluorescence for individual cells, which indicated either cell division or variable uptake of the stain during the staining procedure. We were disappointed to find no conclusive evidence of CFDA stained cells as we encountered high background fluorescence from the majority of testis cells. Although this fluorescence was quenched within 10 s, we were unable to find positive cells with any certainty. We have concluded that PKH26 was more suitable for labeling donor testis cells and that donor cells can be identified for at least 2 months following transfer. Each of the recipients that received PKH26 stained cells retained these cells in the tubule epithelium, which suggests that transfer between different animals, and indeed between breeds, can be achieved. Further studies will aim to demonstrate that donor cells are able to undergo spermatogenesis in the recipient animals.

269. Optimal testicular size of donor and recipient for testicular germ cell transplantation in the bovine

The maturity status of donor and recipient testis appears to be important in the efficiency of testicular germ cell transplantation. When neonatal mice were used as recipients, they show 9.4 times greater colonization and 4 times larger colony size than in the adult.1 The objective of this study in cattle was to investigate the effect of testicular maturity of donor and recipient calves on success of the testis cell transplant procedure. Testicular maturity was measured indirectly by scrotal circumference and donor testicular cells were enzymatically isolated from 8 Angus calves aged 5–7 months (scrotal circumference, SC of 18–22cm) and injected into both testes of 12 recipient calves aged 4–6 months (SC 15–21cm. Donor cells were labeled with the red fluorescent dye PKH26 then transferred into the rete testis under ultrasonographic guidance. Castration of recipients was performed 2–6 months following injection and then frozen sections were used to localize the PKH26 positive donor cells. Five sections from different 5 areas in each testis were prepared and 100 tubules were counted. In 15 of the 24 (63%) testes, PKH positive donor cells were identified. There was no correlation between colonization rate and maturity of donor animal testis for the range of testis sizes studied. Testis cells from donors of SC 18-20 cm or of SC 21-22 did not result in different number of recipient testis with positive cells (7/10 (70%) v. 8/14 (57%)) or the number of positive cells per testis (1.92 ± 0.67% v. 2.5 ± 1.01%). Recipient maturity (SC of 15–18 cm v. SC of 19–21 cm) had no effect on the colonization rate (7/11 (64%) v. 8/13 (62%)); however, there were significantly more positive cells per testis in less mature (SC of 15–18) recipients (3.18±1.21% v. 1.52 ± 0.64% P < 0.05)). In summary we have demonstrated successful testicular germ cell transplantation between calves and while donor testis cell age appeared to have little effect on the efficiency of colonization, less mature testis provided more suitable conditions for colonization. (1)Shinohara T, Orwig KE, Avarbock MR and Brinster RL. (2001) Remodeling of the postnatal mouse testis is accompanied by dramatic changes in stem cell number and niche accessibility. PNAS 98(11), 6186–6191.

300. Differential expression patterns of genes with immune and developmental relevance in individual bovine preimplantation embryos produced by nuclear transfer

The overall efficiency of cloning by somatic cell nuclear transfer (NT) remains low when compared to in-vitro fertilisation (IVF). Inefficient reprogramming of the donor nucleus and epigenetic effects are hypothesized to lead to aberrant gene expression in cloned embryos. In this work differences in gene expression, between blastocysts from IVF and NT derived pre-implantation bovine embryos, were explored using a bovine cDNA array. 439 array elements were identified as being differentially expressed. 102 elements showing upregulation and 337 elements downregulation in NT blastocysts in a pairwise comparison to IVF-derived blastocysts. A major subset (65 elements) of differentially expressed elements comprised immune-related genes, possibly a reflection of the immune-focused cDNA microarray used in this study. For example, several cytokine genes, as well as elements of the innate immune system, were showing elevated expression in NT blastocysts. In addition, two regulatory elements of the same endocrine pathway exhibited a remarkable expression pattern, where the gene for one inhibitor showed upregulation and the gene for another inhibitor showed downregulation in NT blastocysts. Of specific interest is the observation that genes belonging to two growth factor pathways are upregulated in NT embryos. These results suggest an important role for immune-related genes during embryogenesis and indicate that specific cell growth and differentiation factors are of significant interest as targets in defining the abnormalities of preimplantation NT embryo development.

Recycling biosolids to pasture-based animal production systems in Australia: a review of evidence on the control of potentially toxic metals and persistent organic compounds recycled to agricultural land

Biosolids from municipal waste water treatment are commonly used in agriculture as a source of nutrients, organic matter, and irrigation. There is, however, concern that the use of biosolids on pasture can lead to an accumulation of potentially toxic metals (PTM) and persistent organic compounds (POC) in the surface layers of soil and associated herbage that can be ingested by grazing livestock. This review examines the following two key questions. Is the use of these materials in an agricultural setting safe and practical? Is the use of biosolids safe in all climates, on all soils, and is it sustainable over the long term? To answer these important questions, the Australian regulatory framework is examined in light of similar legislation in Europe and the United States on the basis of scientific evidence that underpins the published limits, contaminant gradings, annual loadings, and prescribed restrictions on the use of biosolids in agriculture. The review concludes that the regulatory frameworks currently enacted at State level suffer from a lack of data to underpin the risk assessments conducted to prevent transfer of PTM and POC to the human food chain from livestock production and the basis of published thresholds is poorly defined. The important areas of future research are identified as studies on acquisition and transfer of PTM and POC to grazing animals and the subsequent effect of attenuation of the pollutant on the human food chain, the validation and acceptance of methods to quantify POC in biosolids, the effect of recycling of biosolids on the economic performance of pasture-based agriculture, and the market perception of animal products produced from land receiving biosolids.

263. The successful use of busulfan to deplete endogenous spermatogonia in ram testes

Our research into germ cell transfer builds upon murine research1 and is aimed at using this technique in livestock species. To increase the efficiency of colonization of transplanted germ cells, the recipient testes must be depleted of endogenous spermatogonia, without affecting the supporting cells. Three depletion methods were investigated, heat, cold and chemotherapy. Our first investigation looked at the direct cooling (0ºC) and heating (45ºC) of the testes of 4–6 week old ram lambs. Testes were collected 7 days post treatment. The second investigation involved the systemic injection of busulfan to ram lambs aged 3-4 months. Busulfan is used for preparing recipient mice for testes cell transfer.1 At doses affecting the stem cells of the testes, busulfan will result in mylosuppression. Therefore a preliminary dose response trial was conducted at dose rates 4, 8 and 16mg/kg to determine the most effective dose, without threatening the survival of the animal. Testes were recovered after 3 and 6 weeks. All testes sections followed routine histology and immunochemistry with PGP 9.5 (Table 1). For the heat and cold study, only gonocytes were present and there were no differences in testes weights, tubule diameters or gonocyte numbers in any of the treatment groups. For the busulfan study, dose rates of 8 and 16 mg/kg resulted in severe mylosuppression and euthanasia of 7 out of 8 animals between day 12 and 18, whereas animals in the 4mg/kg group showed only mild clinical effects, that were not life threatening. These results indicate that busulfan reduced endogenous spermatogonia in the pre-pubertal ram. This effect is observed at systemic doses of 4 mg/kg or higher; however, doses of 8 mg/kg and above are lethal to the survival of the animal. The use of direct heat (45ºC) or cold (0ºC) to the testes does not affect gonocyte numbers in ram lambs; however, effects on more mature stages was not studied. (1)Brinster RL, Zimmermann JW. (1994) Spermatogenesis following male germ-cell transplantation. Proc Natl Acad Sci USA 91, 11298–11302.

Delayed stoma formation in Fournier's gangrene

Fournier's gangrene is traditionally treated with prompt surgical debridement and in many cases a diverting colostomy is also fashioned during the same procedure. We present four cases where stoma formation was delayed until the second look procedure. The physiological states at the time of either procedure were compared using POSSUM. The results showed an improvement in the physiological condition in all patients at the time of the second operation, suggesting that a delay can potentially improve prognosis in such cases.

The strength duration test: a novel tool in the identification of occult neuropathy in women with pelvic floor dysfunction

OBJECTIVE

The Strength-duration test (SDT) is a simple minimally invasive measure of muscle innervation, recently adapted for the assessment of the external anal sphincter (EAS). This test can discriminate women with faecal incontinence from controls. The purpose of this study was to determine if the SDT could detect denervation of the EAS in women with weak but anatomically intact EAS and normal pudendal nerve terminal motor latency (PNTML).

PATIENTS AND METHODS

Thirteen women with weak but intact EAS on endoanal ultrasound (EAUS) with normal maximum resting pressure and PNTML were recruited to undergo the SDT. The results from this group were compared to control data for the SDT previously collected in our unit.

RESULTS

Nine of 13 women were found to have SDT above a 95% confidence interval of the mean curve for controls and six had a SDT outside a 90% confidence interval for individuals derived from control data, suggesting denervation of the EAS. The mean area under the curve was significantly higher in our study group compared to controls (91.0 microsmA vs 72.2 microsmA, P = 0.047) as was the current intensity measured at the 1 ms pulse duration (18.2 mA vs 12.94 mA, P = 0.048), typical of denervation with this test.

CONCLUSION

The SDT was abnormal in nine of the 13 study patients. This may partly explain reduced maximum voluntary contraction seen in this group of patients. SDT may be a more sensitive tool in detecting neuropathy than latency measurement.

Effect of season of application on the adhesion, retention and recontamination of herbage by potentially toxic metals and sewage sludge

Grassland in the United Kingdom can accept sewage sludge when, as a result of cropping restrictions, arable land cannot. However, one of the uncertainties associated with the application of sewage sludge to grassland is the potential exposure of the grazing ruminant to sewage sludge particulates adhered to the grass or deposited on the soil surface. The implications of elevated levels of sludge particulates and associated potentially toxic metals (PTMs) are the potential accumulation of PTMs into edible tissues of the grazing animal. Two experiments were performed to investigate the effect of season of application on the adhesion, retention and recontamination of herbage by sewage sludge and PTMs. In each experiment, three treatments were installed, an untreated control, application of sludge in the autumn and application of sludge in the spring. Sewage sludge particulates and PTMs were eluted sequentially 21 days after the application of sludge using water and detergent and the residual (tissue) concentrations were monitored. Total concentrations in each fraction and adhesion indices were calculated. Soil samples taken from the sward treatments after each application showed no elevated concentrations of PTMs or concentrations that approached the maximum concentrations allowed for soils amended with sewage sludge. The amounts of sludge adhered to herbage ranged from 114 to 360 g sludge DM/kg herbage DM. There was evidence of preferential retention of PTMs to herbage. However, during the 21-day no grazing period there was a general decline in concentration of all PTMs. Copper was retained on the herbage for greater periods of time compared to Zn, CD, Pb and Fe (P < 0.01). The proportion of Pb recovered from the water phase increased during the 21-day no grazing period in comparison to Cu, Zn and Fe (P < 0.001). It is concluded that the concentrations of PTMs adhered and integral to herbage as a result of surface application of sewage sludge are likely to fall to acceptable levels in well-managed permanent grassland.

Evidence for an oscillatory signature in atmospheric neutrino oscillations

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)<Deltam(2)<3.0x10(-3) eV(2) and sin((2)2theta>0.90 at 90% confidence level.

Long-term results of the antegrade continent enema procedure for constipation in adults

OBJECTIVE

The aim of this study was to evaluate the long-term results of the Antegrade Continent Enema (ACE) procedure for treating severe constipation in adults.

METHODS

Over 10 years 37 ACE conduits were created in 32 patients (median age 35 years, 26 women) with constipation caused by slow transit, obstructed defaecation or both. Conduits were created from the appendix (n = 20, 54%), ileum (n = 10, 27%), neoappendix caecostomy (n = 5, 14%) or colon (n = 2, 5%). Clinical records were retrospectively reviewed to determine outcome.

RESULTS

After a median follow up of 36 (range 13-140) months, 28 (88%) required at least one further procedure on a primary conduit, including reversal in 19 (59%). Five patients had a second conduit fashioned, two successfully. Conduit type and constipation cause did not significantly influence the rates of ACE reversal or major revision. Ileal conduits were associated with fewer minor revision procedures for stenosis (1 in 7 patients) than appendix conduits (21 in 20 patients). There was one (3%) serious complication. Satisfactory ACE function was ultimately achieved in 47% of patients, at last follow up. After ACE reversal, 9 (28%) patients underwent formation of an end stoma and 3 patients had a colectomy.

CONCLUSIONS

Revision procedures are common, but approximately half of patients can expect satisfactory long-term ACE function. ACE conduit reversal does not preclude subsequent alternative surgical strategies to treat this difficult condition.