Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada.

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Taste preference, food neophobia and nutritional intake in children consuming a cows' milk exclusion diet: a prospective study.

BACKGROUND: Taste exposure in infancy is known to predict food preferences later in childhood. This is particularly relevant in children with cows' milk allergy who consume a substitute formula and/or a cows' milk exclusion (CME) diet early in life. This prospective study aimed to show whether there is a long-term effect of consuming a substitute formula and CME diet on taste preferences and dietary intake. METHODS: Children were predominantly recruited from two large birth cohort studies in the UK. Two groups were recruited: an experimental group of children who had consumed a CME diet during infancy and a control group who had consumed an unrestricted diet during infancy. Parents completed a food neophobia questionnaire and an estimated prospective food diary. Children completed a taste preference test and their growth was assessed. RESULTS: One hundred and one children with a mean age of 11.5 years were recruited (28 CME and 73 controls). Children in the CME group had a significantly higher preference for bitter taste than those in the control group (P < 0.05). There were significant differences between the groups with respect to the intake of some micronutrients, including riboflavin, iodine, sodium and selenium. Food neophobia did not differ between groups. Some 28% of the CME group were overweight/obese compared to 15% of the control group; however, this difference was not statistically significant. CONCLUSIONS: Consuming a substitute formula and/or a CME diet in infancy has a long-term effect on the preference for bitter taste. Differences exist with respect to the intake of some micronutrients, but not macronutrients. There was a nonsignificant trend towards being overweight and obese in children in the CME group.

Changing prevalence of wheeze, rhinitis and allergic sensitisation in late childhood: findings from 2 Isle of Wight birth cohorts 12 years apart.

BACKGROUND: While the prevalence of asthma in children is decreasing or remaining the same, time trends in the prevalence of rhinitis in children are not known. Understanding sensitisation trends may help inform about trends in asthma and rhinitis prevalence. OBJECTIVE: To assess time trends of wheeze, rhinitis and aero-allergen sensitisation prevalence at 10 years of age, we compared two birth cohorts established 12 years apart. To gain insight into differences in disease prevalence, we assessed association of family history, early life exposures and sensitisation with wheeze and rhinitis in each cohort. METHODS: The IoW (Isle of Wight) and FAIR (Food Allergy and Intolerance Research) unselected birth cohorts were established in 1989 and 2001 respectively in IoW. Identical ISAAC questionnaire and skin prick test data were collected and compared at 10 years of age. RESULTS: Over the 12-year period from 2001 to 2012, prevalence of lifetime wheeze, current wheeze and those ever treated for asthma decreased by 15.9% (45.5 vs. 29.6, P < 0.001), 3.9% (18.9 vs. 15, P = 0.020) and 8.2% (31.7 vs. 23.5, P = 0.001), respectively. Conversely, current rhinitis and lifetime rhinitis prevalence increased by 5.5% (22.6 vs. 28.1, P = 0.004) and 13% (18.6 vs. 31.7, P < 0.001), respectively. Atopic status remained stable; however, house dust mite (HDM) sensitisation decreased by 5.6% (19.2 vs. 13.6, P = 0.004) and grass sensitisation increased by 3.5% (12.9 vs. 16.4, P = 0.054). Male sex, parental history of asthma and HDM sensitisation were significantly associated with lifetime wheeze in both cohorts, while maternal smoking during pregnancy was a significant risk factor only in the earlier IoW cohort. Parental history of rhinitis and grass sensitisation was significantly associated with lifetime rhinitis in both cohorts, while HDM sensitisation was significant only for the IoW cohort. CONCLUSION: Contrasting changes were noted with falling wheeze and HDM sensitisation but rising rhinitis and grass sensitisation prevalence. Changing prevalence of aero-allergen sensitisations may explain the different time trends observed in these cohorts.

The specific recognition by macrophages of CD8+,CD45RO+ T cells undergoing apoptosis: a mechanism for T cell clearance during resolution of viral infections.

During viral infections, CD8+,CD45RO+ T populations expand. These primed cells express abundant levels of cytoplasmic granules that contain perforin and TIA-1. Recent work has suggested that the majority of this CD8+ population downregulates Bcl-2 protein expression and is destined to undergo apoptosis. In this study we have investigated the elimination of these apoptotic CD8+ T cells by both human monocyte-derived and murine bone marrow macrophages. We have found that these phagocytes recognize and ingest both apoptotic CD8+ and CD4+ T cells using an alpha v beta 3 (vitronectin receptor)/CD36/thrombospondin recognition system, with the same receptors being used in the recognition of apoptotic neutrophils. These data provide new evidence for a mechanism that enables the clearance of greatly increased populations of CD8+ effector cells which are found during viral infections. This enables cellular homeostasis to occur in the host upon resolution of viral diseases in vivo.

The significance of low bcl-2 expression by CD45RO T cells in normal individuals and patients with acute viral infections. The role of apoptosis in T cell memory.

The bcl-2 gene product has been shown to prevent apoptotic cell death. We have now investigated the bcl-2 protein expression by resting and activated mature T cell populations. Freshly isolated CD45RO+ T cells within CD4+ and CD8+ subsets expressed significantly less bcl-2 than CD45RO- (CD45RA+) T cells (p < 0.001). When CD45RA+ T cells within both CD4+ and CD8+ subsets were activated in vitro, the transition to CD45RO phenotype was associated with a decrease in bcl-2 expression. Patients with acute viral infections such as infectious mononucleosis caused by Epstein-Barr virus infections or chickenpox, resulting from varicella zoster virus infection, had circulating populations of activated CD45RO+ T cells which also showed low bcl-2 expression. In these patients, a significant correlation was seen between low bcl-2 expression by activated T cells and their apoptosis in culture (r = 0.94, p < 0.001). These results suggest that the primary activation of T cells leads to the expansion of a population that is destined to perish unless rescued by some extrinsic event. Thus the suicide of CD45RO+ T cells could be prevented by the addition of interleukin 2 to the culture medium which resulted in a concomitant increase in the bcl-2 expression of these cells. Alternatively, apoptosis was also prevented by coculturing the activated T lymphocytes with fibroblasts, which maintained the viability of lymphoid cells in a restinglike state but with low bcl-2 expression. The paradox that the CD45RO+ population contains the primed/memory T cell pool yet expresses low bcl-2 and is susceptible to apoptosis can be reconciled by the observations that maintenance of T cell memory may be dependent on the continuous restimulation of T cells, which increases their bcl-2 expression. Furthermore, the propensity of CD45RO+ T cells to extravasate may facilitate encounter with fibroblast-like cells in tissue stroma and thus be an important additional factor which promotes the survival of selected primed/memory T cells in vivo.

Time trends in the prevalence of peanut allergy: three cohorts of children from the same geographical location in the UK.

BACKGROUND: This article investigated the prevalence of peanut allergy in three cohorts of children born in the same geographical location, Isle of Wight, UK and seeks to determine whether the prevalence of peanut allergy has changed between 1994 and 2004. METHODS: Three cohorts of children (age 3-4 years) born on the Isle of Wight, were assessed for peanut allergy and the outcomes compared: Cohort A: Born in 1989; reviewed at 4 years of age (n = 2181). Cohort B: Born between 1994 and 1996; reviewed between 3 and 4 years of age (n = 1273). Cohort C: Born between 2001 and 2002; reviewed at 3 years of age (n = 891). RESULTS: Peanut sensitization increased significantly from 1.3% in Cohort A to 3.3% (P = 0.003) in Cohort B before falling back to 2.0% in Cohort C (P = 0.145). Similarly, clinical peanut allergy increased significantly from 0.5% in Cohort A to 1.4% (P = 0.023) in Cohort B, with a subsequent fall to 1.2% in Cohort C (P = 0.850). CONCLUSIONS: Our data from three cohorts of 3- to 4-year-old children born in the same geographical area shows that peanut allergy prevalence has changed over time. Peanut sensitization and reported allergy in children born in 1994-1996 increased from 1989 but seems to have stabilized or slightly decreased since the late 1990s, although not significant.

Reaching every district - development and testing of a health micro-planning strategy for reaching difficult to reach populations in Mongolia.

CONTEXT: Since the 1990s, Mongolia has undergone a rapid social and economic transition with migration to the urban areas of the national capital Ulaanbaatar. The main reasons for the migration are social sector decline in rural areas and the potential for employment opportunities in urban areas. There are also new internal patterns of migration in rural and remote areas relating to recent developments in the economic sector. Despite recent innovations in health system management in Mongolia, in some urban and rural and remote locations health services are not sufficiently accessed by the most socially and economically disadvantaged populations. These concerns provided the motivation for the Ministry of Health of Mongolia and development partners to attempt to access the most difficult to reach populations through the development of a micro-planning process referred to as the 'Reaching Every District strategy' (RED). This article describes and analyses RED micro-planning processes and content, and highlights the lessons learned. The main source of data for this planning system development was in the development and testing of the micro-planning process in Byanzurkh District, Ulaanbaatar in June 2008. INTERVENTION: The principal intervention developed and trialed was a health micro-planning strategy for improved access to immunization and maternal and child health services for difficult to reach populations. The planning methodology was a problem-solving approach progressing from health mapping to barrier analysis, to activity planning and costing and finally to monitoring and evaluation. LESSONS LEARNED: Main success factors in the development of the planning methodology were the use of barrier analysis and mapping approaches for data analysis and problem solving at the local level, and re-orientation of management approaches from 'inspection' to supportive supervision. Additionally, although the RED strategy is intended to be an immunization-specific intervention internationally, evidence from the development and trial of the process in Mongolia indicates its potential for wider health systems applications. This is particularly so for detecting and responding to the maternal and child health service needs of the more difficult to reach sub-populations.

Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life.

BACKGROUND: Prevalence and incidence of food hypersensitivity (FHS) and its trends in early childhood are unclear. METHODS: A birth cohort born on the Isle of Wight (UK) between 2001 and 2002 was followed-up prospectively. Children were clinically examined and skin prick tested at set times and invited for food challenges when indicated. RESULTS: Nine hundred and sixty-nine children were recruited and 92.9%, 88.5% and 91.9% of them respectively were assessed at 1, 2 and 3 years of age. Prevalence of sensitization to foods was 2.2%, 3.8% and 4.5% respectively at these ages. Cumulatively, 5.3% [95% confidence interval (CI): 3.9-7.1] children were sensitized to a food. Using open food challenge and a good clinical history, the cumulative incidence of FHS was 6.0% (58/969, 95% CI: 4.6-7.7). Based on double-blinded, placebo-controlled, food challenge (DBPCFC) and a good clinical history, the cumulative incidence was 5.0% (48/969, 95% CI: 3.7-6.5). There is no evidence to suggest that the incidence of FHS has increased, comparing these results with previous studies. Overall, 33.7% of parents reported a food-related problem and of these, 16.1% were diagnosed with FHS by open challenge and history and 12.9% by DBPCFC and history. Main foods implicated were milk, egg and peanut. CONCLUSIONS: By the age of 3 years, 5-6% of children suffer from FHS based on food challenges and a good clinical history. There were large discrepancies between reported and diagnosed FHS. Comparing our data with a study performed in the USA more than 20 years ago, there were no significant differences in the cumulative incidence of FHS.

Multiple G-protein-dependent pathways mediate the antisecretory effects of somatostatin and clonidine in the HT29-19A colonic cell line.

Using the functionally differentiated colonic cell line, HT29-19A, we have examined sites at which inhibitory G-proteins mediate the antisecretory actions of somatostatin (SST) and the alpha 2-adrenergic agonist, clonidine (CLON) at the epithelial level. Both agents caused a dose-dependent inhibition (EC50:SST 35 nM; CLON 225 nM) of Cl- secretion (assessed by changes in short circuit current) activated by cAMP-mediated agonists, PGE2 and cholera toxin. Inhibition was accompanied by a reduction in intracellular cAMP accumulation and could be blocked by pretreatment with pertussis toxin at a concentration (200 ng/ml) which activated ADP-ribosylation of a 41-kD inhibitory G protein in HT29-19A membranes. Secretion stimulated by the permeant cAMP analogue, dibutyryl cAMP, was also inhibited by SST and CLON (30-50%; P < 0.005), indicating additional inhibitory sites located distal to cAMP production. Both agents were effective inhibitors of secretion mediated through the Ca2+ signaling pathway. SST (1 microM) and CLON (10 microM) reduced the Isc response to the muscarinic agonist, carbachol, by 60-70%; inhibition was reversed in pertussis toxin-treated cells. These effects did not, however, involve inhibition of the carbachol-induced increase in cellular inositol 1,4,5-trisphosphate levels or the rise in cytosolic calcium, [Ca]i. Inhibition by SST of secretion induced by phorbol 12,13 dibutyrate but not by the calcium agonist, thapsigargin, suggests that SST may act at a distal inhibitory site in the Ca(2+)-dependent secretory process activated by protein kinase C. We conclude that SST and alpha 2-adrenergic agonists can act directly on intestinal epithelial cells to exert a comprehensive inhibition of Cl- secretion mediated through both cAMP and Ca2+/protein kinase C signaling pathways. Inhibition is mediated via pertussis toxin-sensitive G-proteins at sites located both proximal and distal to the production of second messengers.

Developments in immunization planning in Cambodia--rethinking the culture and organization of national program planning.

INTRODUCTION: As part of its health system reconstruction following decades of civil war, Cambodia undertook a program of health sector reform in 1996 to expand coverage of essential health services to the population of 14 million, 80% of whom are resident in over 13 000 rural villages. During this reform period, one of the major national health programs, the National Immunization Program (NIP), adapted its planning system to accommodate changes in social and health sector structure. AIMS: The aims of this article are to review changes made in the approach to national immunization planning and to illustrate how these adaptations can help identify future challenges and opportunities for further improving immunization coverage in Cambodia. Sources of information for the study include immunization plans and data from international and national sources, as well as data from the national health information system. Findings of review: Management and service delivery reforms undertaken by the NIP include (1) strengthening links between immunization, health sector and international health planning; (2) development of immunization program multiyear and financial sustainability plans; (3) strengthening of national program decision making structures and processes; (4) widening of decentralized stakeholder participation in health planning; and (5) implementation of service level micro-planning. OUTCOMES: These management reforms have been associated with significant improvement in public health program performance and outcomes during this period (2003-2006). There has been an increase in vaccination coverage for children under the age of one year, over a five-year period (increase of 29% for fully immunized child at one year of age), with no significant differences in vaccination rates between urban and rural areas, and a sharp decrease in the incidence of vaccine preventable diseases. CONCLUSION: The NIP is now well positioned to take on additional challenges in coming years associated with expanding international partnerships, the continued development of civil society, further health system decentralization, and the requirement to further improve coverage in support of global and regional disease elimination goals. However, as costs continue to rise, planners in the future will need to emphasize the economic and public health benefits of immunization programs in order to sustain increasing levels of national and international investment.

Ca(2+)-mobilising agonists potentiate forskolin- and VIP-stimulated cAMP production in human colonic cell line, HT29-cl.19A: role of [Ca2+]i and protein kinase C.

This study has examined the involvement of the Ca(2+)-signalling pathway in the regulation of agonist-stimulated cAMP responses in the human colonic adenocarcinoma cell line, HT29-cl.19A. The muscarinic agonist, carbachol (CCh) stimualted rapid increases in cellular IP3 and cytosolic Ca2+, [Ca2+]i in HT29-cl.19A cells. These were accompanied by a small but significant increase in basal cAMP levels and a marked (3-4-fold) potentiation of both forskolin- (FSK) and VIP-stimulated cAMP generation. Similar effects were observed with two other Ca(2+)-mobilising agonists, neurotensin and ATP. The failure of CCh to elicit potentiation of adenylate cyclase in broken cell preparations indicated an indirect action. Potentiation could be mimicked by the calcium ionophore, ionomycin, and thapsigargin and inhibited 70-90% by depleting intracellular Ca2+ stores suggesting that a rise in [Ca2+]i is the primary mediator of this response. In contrast, increasing [Ca2+]i levels to > 500 nM caused a significant inhibition of FSK-stimulated cAMP generation. The involvement of protein kinase C (PKC) was also assessed. PKC activators phorbol 12,13 dibutyrate (PDB) and 1-oleoyl-2-acetyl glycerol (OAG) potentiated FSK-stimulated cAMP production by 50-70% though PDB markedly inhibited the cAMP response to the receptor-mediated cAMP agonist, VIP. Neither effect could be elicited by the inactive phorbol ester, 4 alpha-phorbol, 12,13 didecanoate (PDD). PKC inhibitors staurosporine and H7 reduced by approximately 25% the CCh-induced potentiation of FSK-stimulated cAMP generation. In conclusion, these results suggest that stimulation of the phosphoinositidase C pathway in HT29-cl.19A colonocytes induces a 'sensitisation' of the adenylate cyclase system resulting in a dramatic amplification of agonist-stimulated cAMP generation. Increases in [Ca2+]i appear to be an important mediator of potentiation though activation of PKC may also play a significant role.

Cytomegalovirus induced up-regulation of LFA-3 (CD58) and ICAM-1 (CD54) is a direct viral effect that is not prevented by ganciclovir or foscarnet treatment.

Cytomegalovirus (CMV) is a major pathogen in transplant recipients and AIDS patients, and the virus may also play a role in allograft rejection. Previous work from this laboratory demonstrated increased cell surface expression of the adhesion molecules ICAM-1 (CD54) and LFA-3 (CD58) following CMV infection in vitro. We investigated whether the induction of adhesion molecules by CMV was a direct viral effect or secondary to cytokine induction. Cytokines known to up-regulate ICAM-1, such as TNFalpha or IL-1beta, were not detected in the supernatants of infected fibroblasts, and neutralizing antibodies against these cytokines did not abrogate the induction of either ICAM-1 or LFA-3 by CMV. Infected cell supernatants had increased levels of IL-6, IL-8 and IFNbeta however, the addition of recombinant forms of these cytokines did not affect adhesion molecule expression. Neither virus-free infected cell supernatants nor UV-inactivated virus up-regulated adhesion molecules, demonstrating that the induction of ICAM-1 and LFA-3 by CMV was a direct effect requiring infectious virus. Effective antiviral treatment with ganciclovir or foscarnet accentuated rather than abrogated the up-regulation of adhesion molecules, suggesting that CMV immediate early/early gene expression, which is not blocked by such treatment, was responsible for the adhesion molecule induction. Thus, despite effective antiviral therapy in the transplant recipient, CMV infected cells may continue to provide a focus of proinflammatory activity, which could contribute to immunopathology and/or accentuate graft rejection or graft-versus-host disease in vivo.

The effect of cytomegalovirus infection on the host response to foreign and hapten-modified self histocompatibility antigens.

The effect of murine cytomegalovirus (MCMV) infection on the host's ability to respond to allogeneic or hapten-modified syngeneic histocompatibility antigens was characterized by an early suppressive phase followed by a phase of enhancement. Suppression of the potential to respond to allogeneic H-2 antigens, as measured by an in vitro cell-mediated lympholysis assay, was seen on days 2-4 postinfection with MCMV, and was greatest at larger doses of virus and in mice with H-2 haplotypes associated with genetic susceptibility to MCMV. In mice of the C57BL genetic background, such responses had returned to normal levels by day 6 and thereafter (days 7-13) the potential of the infected host to respond to allogeneic histocompatibility determinants was markedly enhanced compared with uninfected control mice. This enhancement of alloreactivity was maximal at lower doses of virus and was coincident with the emergence of reactivity to self antigens, as measured by autoantibody production. A similar pattern of time-dependent suppression and enhancement of the hapten modified self cytotoxic response was observed. Enhancement of alloreactivity during MCMV infection was dependent on the genetic constitution of the host with the response of BALB/c mice remaining in a suppressive phase for up to 17 days postinfection. The possibility that this in vitro finding of enhanced alloreactivity during MCMV infection underlies the clinical observations of association between episodes of kidney allograft rejection and cytomegalovirus infection is discussed.

Augmentation of graft-versus-host reaction by cytomegalovirus infection resulting in interstitial pneumonitis.

The severity of the graft-versus-host (GVH) reaction, judged by splenomegaly and immunosuppression, was augmented by murine cytomegalovirus (MCMV) infection. Profound GVH-induced immunosuppression was seen in adult unirradiated MCMV-infected F1, mice even after challenge with extremely low doses of parental spleen cells. Mice receiving MCMV+GVH challenge died from days 16-21, with interstitial pneumonia being the most prominent pathological lesion. Pulmonary disease was unrelated to levels of viral replication in the lung. These results suggest that in human marrow recipients, cytomegalovirus infection may play a primary role both in provoking or accentuating GVH disease, as well as in the development of interstitial pneumonia.

Cytomegalovirus and beta 2 microglobulin in urine specimens. Reciprocal interference in their detection is responsible for artifactually high levels of urinary beta 2 microglobulin in infected transplant recipients.

We have previously shown that the binding of host beta 2 microglobulin (beta 2 m) by cytomegalovirus (CMV) in body fluids masks the viral antigenic determinants preventing its detection by CMV-specific monoclonal antibodies. We now report that the recognition of CMV-bound beta 2m by anti-beta 2m-specific antibodies in assays for beta 2m, results in erroneously high readings for beta 2m levels in urine specimens containing CMV. Urinary beta 2m levels have previously been reported to be elevated in patients with CMV infection--however, when virion bound beta 2m was removed by ultracentrifugation of urine specimens, the levels of free beta 2m were not found to be elevated in these patients. Since CMV is frequently excreted by transplant recipients and acquired immunodeficiency syndrome patients, our data suggest that measurements of urinary beta 2m levels in such patients are unreliable unless the urine specimens are confirmed to be free of CMV before analysis.

The nifedipine gastrointestinal therapeutic system (GITS). Evaluation of pharmaceutical, pharmacokinetic and pharmacological properties.

Nifedipine is a short-acting calcium antagonist formulated into several different oral preparations, each of which offers a distinct drug release profile. Of these, the nifedipine gastrointestinal therapeutic system (GITS) affords (rate)-controlled-release (CR) and once-daily administration. Although it is recognised that CR drug formulations may enhance the treatment compliance of patients by reducing the number of daily doses, there are several pharmaceutical, pharmacokinetic and pharmacological considerations which may influence the ultimate selection of a particular dosage form. The formulation design of the nifedipine GITS involves an osmotic pump process which provides approximately zero-order delivery of the drug. This mechanism serves to prevent the possibility of dose dumping, but more importantly allows for maintenance of the relatively constant plasma drug concentrations assumed necessary to maintain smooth control of blood pressure. The pharmacokinetic characteristics of the nifedipine GITS have been evaluated in both single- and multiple-dose studies. The GITS formulation provides drug concentrations which reach a plateau within 6 hours after administration of a single dose, and continue at that concentration until at least 24 hours after administration. In this way large fluctuations in plasma drug concentrations are avoided, which may improve the efficacy and tolerability of the drug. Although a trend showing a small increase in the 24-hour plasma nifedipine concentrations has been observed by our group from some single-dose studies, it does not appear to be clinically relevant. One potentially important disadvantage of the GITS compared with 'naturally' long-acting agents is that the 'intrinsic' pharmacokinetic properties of nifedipine may be exposed in poorly compliant patients, leading to extended periods of subtherapeutic drug concentrations. Drug delivery by the nifedipine GITS is unaffected by changes in pH and gastrointestinal (GI) motility, but the rate of drug release can increase slightly with food intake (although absolute bioavailability remains unchanged). No studies have been conducted to determine the average GI transit time of this particular dosage form, but it is possible that inadequate retention may occur in some patients, perhaps leading to less optimal clinical outcomes. For example, the median GI transit time for both oxprenolol and metoprolol Oros drug delivery systems has been reported as 27.4 hours, with individual times ranging from 5.1 to 58.3 hours. The possibility of inadequate GI retention of the nifedipine GITS is perhaps more likely in patients who have pre-existing GI motility disorders or who are taking other medications that enhance GI motility. The interaction between grapefruit juice and nifedipine is interesting, considering that the exact mechanism involved has yet to be determined. Nonetheless, inhibition of presystemic metabolic processes (probably involving liver enzymes but possibly also enzymes contained within the wall of the small intestine) is likely to be a factor in the increased bioavailability of nifedipine observed in individuals coingesting grapefruit juice. Thus, potential nifedipine formulation differences with respect to the degree of interaction with grapefruit juice may occur if a significant degree of extrahepatic metabolism is involved. The majority of clinical trials with the nifedipine GITS have assessed its efficacy in patients with mild-to-moderate essential hypertension, and have found it to be at least equivalent to other dosage forms of the drug. Since there is limited information available directly comparing the efficacy and adverse effects of the different types of nifedipine formulation, little attention has been focused on this subject. However, modifying the rate and duration of nifedipine release may profoundly affect the clinical performance of this drug. A slower rate of intravenous nifedipine infusion has been shown to reduce the incide

IL2 activated killer cells may contribute to cytomegalovirus induced marrow hypoplasia after bone marrow transplantation.

Cytomegalovirus (CMV) infection remains the commonest cause of infective death following allogeneic bone marrow transplantation (BMT). CMV disease post-BMT occurs in the context of compromised cellular defence mechanisms and is associated with marrow hypoplasia and pneumonitis. However, CMV infection induces release of interleukin 2 (IL2) which in turn generates MHC unrestricted lymphokine activated killer (LAK) cells. We have investigated whether recruitment of IL2 activated MHC unrestricted defence mechanisms post-transplant can be implicated in the marrow hypoplasia that frequently accompanies CMV infection. The results show that IL2 activated peripheral blood mononuclear cells (PBMC) have substantial cytotoxicity against MHC matched and MHC mismatched marrow fibroblasts but that this activity is not specific for CMV infected fibroblasts; uninfected target cells are also equally killed. Furthermore, post-BMT PBMC show greater responsiveness to IL2 than normal PBMC in killing of marrow fibroblasts. We provide a hypothesis from these observations which may explain some of the consequences of CMV infection post-BMT. Local production of IL2 activated cytotoxic cells which would be generated during CMV infection would damage uninfected as well as infected marrow fibroblasts and thereby could compromise haemopoietic growth factor production by marrow fibroblasts. Similarly generated cytotoxicity in the lung may accompany CMV pneumonitis. Our results suggest that administration of anti-IL2 receptor antibody may have a therapeutic role in CMV disease post-BMT as has recently been shown in graft-versus-host disease.

Impact of liver disease and hepatitis infections on allogeneic bone marrow transplantation in Europe: a survey from the European Bone Marrow Transplantation (EBMT) Group--Infectious Diseases Working Party.

This survey investigated allogeneic bone marrow transplantation (BMT) policy in European BMT units by questionnaire, in relation to pre-transplant liver disease. It also assessed diagnostic standards for viral hepatitis infections and their prevalence in BMT candidates. Sixty-three EBMT centers from 22 countries participated in the survey. Median pre-transplant prevalences of HBsAg and anti-HCV positivity were 3.5% (range 0-15%) and 5% (range 0-45%), respectively. Forty-six (73%) centers adopt the policy of cancelling or postponing BMT in patients with ALT abnormalities but in four of these centers, BMT is not delayed when progressive disease or acute leukemia is present. In 17 institutions (27%) BMT was reported to be carried out irrespective of transaminase values. Data on fatal post-BMT liver disease were provided by 45 centers. The overall mortality rate for liver failure was 4.5% (258 of 5788) with no differences between centers performing or not performing BMT in cases of ALT elevation. These results indicate that there is strong concern in most European BMT units about performing BMT in the presence of ALT elevation and prospective studies on its real impact on fatal post-BMT liver disease should be conducted.

Practices for cytomegalovirus diagnosis, prophylaxis and treatment in allogeneic bone marrow transplant recipients: a report from the Working Party for Infectious Diseases of the EBMT.

During the past few years major progress has been made in the diagnosis and therapy of CMV infection after allogeneic BMT. The aim of this survey was to investigate the use of diagnostic techniques, use of prophylaxis and the therapeutic strategies among members of the EBMT. Seventy centers from 20 countries responded to the survey. Sixty-seven centers (96%) routinely tried to diagnose CMV from the blood. Fifty-seven centers used standard or rapid isolation techniques. Thirty-seven centers used one of the newly developed techniques, antigenemia detection in leukocytes or PCR together with isolation, while 10 centers used one of these two techniques without standard isolation. Fifty-five centers regularly performed bronchoscopy and bronchoalveolar lavage on the suspicion of CMV pneumonia but only 12 centers required detection of CMV in specimens from the lavage or lungs as the indication to start therapy; 31 centers started therapy on symptoms of pneumonia combined with CMV detection from any site. Prophylaxis was used in 54 centers (84%). The most commonly used regimen was high-dose acyclovir which was used by 42 centers, while seven centers used ganciclovir. The strategy of early therapy was used by 53 centers (76%) and was most frequently based on detection of viremia or CMV antigen in the blood. CMV pneumonia was treated by a combination of ganciclovir and i.v. immunoglobulin by 64 centers, by foscarnet and immunoglobulin in 5 centers and by ganciclovir alone in 5 centers. CMV gastrointestinal disease was treated by antiviral therapy alone in 18 centers and by a combination of antiviral therapy and iv immunoglobulin in 46 centers.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunisations after bone marrow transplantation: results of a European survey and recommendations from the infectious diseases working party of the European Group for Blood and Marrow Transplantation.

Increased numbers of recipients of BMTs and autologous BMTs are becoming long-term survivors. Existing data support that loss of protective immunity to agents such as tetanus and poliovirus is common in patients who received BMTs and autologous BMTs. Thus, a reimmunisation programme is needed to ensure immunity. A questionnaire concerning immunisation practices was sent to EBMT member centres. The immunisation practices varied extensively in the 59 responding BMT and 48 responding autologous BMT centres. Sixty five per cent of responding centres routinely immunise patients who received allogeneic BMTs whereas 37% were routinely immunising recipients of autologous BMTs. Tetanus toxoid and inactivated poliovirus vaccine were the most frequently used vaccines in both BMT and autologous BMT centres. Immunisations of recipients of both BMTs and autologous BMTs with tetanus toxoid, diphtheria toxoid, inactivated poliovirus vaccine and influenza vaccine are recommended. Other vaccines, and in particular live attenuated vaccines, may be considered on an individual basis.