The role of mast cells in gastro-intestinal nematode parasitism of the goat

Studies were conducted to investigate the in vivo and in vitro responses of caprine mast cells to challenge with gastro-intestinal nematode parasites. Initial work concentrated on the isolation and purification of a mast cell-specific neutral granule protease, termed goat mast cell protease (GMCP), from homogenates of caprine intestinal tissue. Immunological, biochemical and molecular characterisation studies localised the enzyme to caprine mast cells, confirmed its similarity to a sheep mast cell protease (SMCP), uncovered cDNA coding for a second mast cell protease (termed GMCP II) and highlighted a dual chymotrypsin and trypsinlike substrate specificity. This latter finding categorised it alongside SMCP and bovine duodenase as a member of the novel 'janus' class of dual-specific ruminant serine esterases. Polyclonal and monoclonal antibodies were raised against GMCP and an enzyme linked immunosorbent assay (ELISA) constructed which was used to determine the functional activity of mast cells. This was achieved initially in the tissues of animals undergoing experimental infections with nematodes and subsequently in ex vivo populations of isolated intestinal mast cells and bone marrow derived mast cells grown in vitro.In vivo studies comparing yearling goats and kids with lambs undergoing primary and secondary infections with Telodorsagia circumcincta demonstrated that after secondary infections the goat and kid abomasal tissues retained more worms and, after both primary and secondary infections, contained considerably less GMCP than the equivalent lamb abomasal tissues. A significant mastocytosis response following repeated exposure to the parasites was also demonstrated in both species, although the secondarily infected goats and kids contained proportionately more globule leukocytes (GL) than the lambs. Blood and tissue eosinophil responses were variable, but measurements for total serum IgE demonstrated that the goats, kids and lambs developed increased mean total serum IgE levels after primary and secondary exposure to nematodes.Caprine mast cells were also studied in isolation through ex vivo purification of caprine intestinal mucosal mast cells (MMC) and GL and in vitro growth of bone marrow marrow derived mast cells (BMMC) from haemopoietic precursor cells using recombinant ovine cytokines. Caprine and ovine BMMC cultures were characterised in terms of their cell morphology, GMCP, SMCP and acid hydrolase content during cytokine dose and time response experiments, which demonstrated the significant effects of ovine stem cell factor on BMMC proliferation and long term culture viability when used in combination with ovine interleukin-3. Biochemical and morphological studies, including the use of electron microscopy, were carried out to compare isolated goat MMC with goat and sheep BMMC as well as with isolated sheep MMC. These highlighted significant differences in the mediator content of the different cell populations with markedly less protease in caprine BMMC when compared with ovine BMMC and caprine MMC.Goat MMC and BMMC were stimulated to release the contents of their cytoplasmic granules in the presence of synthetic secretogogues and crude nematode antigen preparations. Initial results showed that calcium ionophore A21387 produced the greatest dose-related release of mediators from caprine BMMC, indicating that the majority of the cells present in these cultures possessed a functional phenotype similar to that associated with MMC. Subsequent studies involving crude antigen preparations derived from T. circumcincta and Haemonchus contortus demonstrated that they were capable of inducing BMMC activation. This activation response could also be enhanced after passive sensitisation of the cells with IgE-containing serum or lymph preparations obtained from animals undergoing experimental exposure to parasitic nematodes

Assisted reproductive technology in the USA: is more regulation needed?

The regulation of assisted reproductive technologies is a contested area. Some jurisdictions, such as the UK and a number of Australian states, have comprehensive regulation of most aspects of assisted reproductive technologies; others, such as the USA, have taken a more piecemeal approach and rely on professional guidelines and the general regulation of medical practice to govern this area. It will be argued that such a laissez-faire approach is inadequate for regulating the complex area of assisted reproductive technologies. Two key examples, reducing multiple births and registers of donors and offspring, will be considered to illustrate the effects of the regulatory structure of assisted reproductive technologies in the USA on practice. It will be concluded that the regulatory structure in the USA fails to provide an adequate mechanism for ensuring the ethical and safe conduct of ART services, and that more comprehensive regulation is required

Perinatal mortality following assisted reproductive technology treatment in Australia and New Zealand, a public health approach for international reporting of perinatal mortality

BACKGROUND There is a need to have uniformed reporting of perinatal mortality for births following assisted reproductive technology (ART) treatment to enable international comparison and benchmarking of ART practice. METHODS The Australian and New Zealand Assisted Reproduction Database was used in this study. Births of ≥ 20 weeks gestation and/or ≥ 400 grams of birth weight following embryos transfer cycles in Australia and New Zealand during the period 2004 to 2008 were included. Differences in the mortality rates by different perinatal periods from a gestational age cutoff of ≥ 20, ≥ 22, ≥ 24, or ≥ 28 weeks (wks) to a neonatal period cutoff of either < 7 or < 28 days after birth were assessed. Crude and specific (number of embryos transferred and plurality) rates of perinatal mortality were calculated for selected gestational and neonatal periods. RESULTS When the perinatal period is defined as ≥ 20 wks gestation to < 28 days after birth, the perinatal mortality rate (PMR) was 16.1 per 1000 births (n = 630). A progressive contraction of the gestational age groups resulted in marked reductions in the PMR for deaths at < 28 days (22 wks 11.0; 24 wks 7.7; 28 wks 5.6); and similarly for deaths at < 7 days (20 wks 15.6, 22 wks 10.5; 24 wks 7.3; 28 wks 5.3). In contrast, a contraction of the perinatal period from < 28 to < 7 days after birth only marginally reduced the PMR from 16.2 to 15.6 per 1000 births which was consistent across all gestational ages. The PMR for single embryo transfer (SET) births (≥ 20 weeks gestation to < 7 days post-birth) was significantly lower (12.8 per 1000 SET births) compared to double embryo transfer (DET) births (PMR 18.3 per 1000 DET births; p < 0.001, Fisher’s Exact Test). Similarly, the PMR for SET births (≥ 22 weeks gestation to < 7 days post-birth) was significantly lower (8.8 per 1000 SET births, p < 0.001, Fisher’s Exact Test) when compared to DET births (12.2 per 1000 DET births). The highest PMR (50.5 per 1000 SET births, 95% CI 36.5-64.5) was for twins following SET births (≥ 20 weeks gestation to < 7 days post-birth) compared to twins following DET (23.9 per 1000 DET births, 95% CI 20.8-27.1). CONCLUSION Reporting of perinatal mortality of ART births is an essential component of quality ART practice. This should include measures that monitor the impact on perinatal mortality of multiple embryo transfer. We recommend that reporting of perinatal deaths following ART treatment, should be stratified for three gestation-specific perinatal periods of ≥ 20, ≥ 22 and ≥ 28 completed weeks to < 7 days post-birth; and include plurality specific rates by SET and DET. This would provide a valuable international evidence-base of PMR for use in evaluating ART policy, practice and new research.Elizabeth A Sullivan, Yueping A Wang, Robert J Norman, Georgina M Chambers, Abrar Ahmad Chughtai and Cynthia M Farquha

Perinatal outcomes from IVF and ICSI

Michael Davie

Assisted reproductive technology in Australia and New Zealand 2010

Use of assisted reproductive technology treatment cycles There were 61,774 assisted reproductive technology (ART) treatment cycles performed in Australia and New Zealand in 2010 (56,489 and 5,285 respectively), representing decreases of 13.4% for Australia and 1% for New Zealand from the previous year. The substantial decrease in cycles in Australia coincided with a change in government funding for fertility treatment. There were 30,588 women who undertook autologous ART treatment in Australia and New Zealand in 2010. On average, 1.9 cycles were undertaken in Australia compared with 1.4 cycles in New Zealand. Women used their own oocytes or embryos in 94.8% of treatments (autologous), and 35.1% of all cycles used frozen/thawed embryos. Women’s age and parity One-quarter (25%) of ART treatment cycles were undertaken by women who had previously given birth. The average age of women undergoing autologous cycles was 36. In contrast, the average age of women undergoing ART treatment using donor oocytes or embryos was 5 years older (40.9). Almost one-quarter (24.3%) of autologous cycles in 2010 were undertaken by women aged 40 or older compared with 20.6% in 2006. Treatment outcomes and number of babies Of the 61,774 initiated treatment cycles, 23.9% resulted in a clinical pregnancy, and 18.1% in a live delivery (the birth of at least one liveborn baby). There were 12,056 liveborn babies following ART treatments in 2010, with almost three-quarters of these (74.4%) being fullterm singletons of normal birthweight. There was a higher live delivery rate in younger women. For women aged 30-34, the live delivery rate was 26.8% for fresh cycles and 21.8% for thaw cycles. For women aged over 44, it was less than 1% and 8.4% respectively. Trends in ART procedures In the last 5 years there has been a shift from day 2-3 embryo (cleavage stage) transfers to day 5–6 embryo (blastocyst) transfers. The proportion of blastocyst transfers has increased from 27.1% in 2006 to 52.1% in 2010. Similarly, there has been an increase in the transfer of vitrified (ultra-rapid frozen) embryos. Compared with 2009, the proportion has more than doubled from 18.3% to 38.2%. Multiple births A continuing trend in ART treatment in Australia and New Zealand has been the reduction in the rate of multiple birth deliveries, with a decrease from 12% in 2006 to 7.9% in 2010. This was achieved by clinicians and patients shifting to single embryo transfer, the proportion of which increased from 56.9% in 2006 to almost 70% in 2009 and 2010. Importantly, this decrease in the multiple delivery rate was achieved while clinical pregnancy rates remained stable at about 23% per cycle

Biosecurity and disease prevention

SIGLEAvailable from British Library Document Supply Centre-DSC:6106.1992(vol 3 no 12) / BLDSC - British Library Document Supply CentreGBUnited Kingdo