A Potent Kalihinol Analogue Disrupts Apicoplast Function and Vesicular Trafficking in P. falciparum Malaria

Here we report the discovery of MED6-189, a new analogue of the kalihinol family of isocyanoterpene (ICT) natural products. MED6-189 is effective against drug-sensitive and -resistant P. falciparum strains blocking both intraerythrocytic asexual replication and sexual differentiation. This compound was also effective against P. knowlesi and P. cynomolgi. In vivo efficacy studies using a humanized mouse model of malaria confirms strong efficacy of the compound in animals with no apparent hemolytic activity or apparent toxicity. Complementary chemical biology, molecular biology, genomics and cell biological analyses revealed that MED6-189 primarily targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses in P. falciparum revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. The high potency of MED6-189 in vitro and in vivo, its broad range of efficacy, excellent therapeutic profile, and unique mode of action make it an excellent addition to the antimalarial drug pipeline.

Distressing psychotic-like experiences, cognitive functioning and early developmental markers in clinically referred young people aged 8-18 years

PURPOSE

Neurocognitive difficulties and early childhood speech/motor delays are well documented amongst older adolescents and young adults considered at risk for psychosis-spectrum diagnoses. We aimed to test associations between unusual or psychotic-like experiences (PLEs), co-occurring distress/emotional symptoms, current cognitive functioning and developmental delays/difficulties in young people (aged 8-18 years) referred to Child and Adolescent Mental Health Services in South London, UK.

METHODS

Study 1 examined receptive language, verbal learning and caregiver-reported speech and motor delays/difficulties in a sample of 101 clinically-referred children aged 8-14 years, comparing those reporting no PLEs (n = 19), PLEs without distress (n = 16), and PLEs with distress (n = 66). Study 2 tested associations of severity of distressing PLEs with vocabulary, perceptual reasoning, word reading and developmental delays/difficulties in a second sample of 122 adolescents aged 12-18 years with distressing PLEs.

RESULTS

In Study 1, children with distressing PLEs had lower receptive language and delayed recall and higher rates of developmental delays/difficulties than the no-PLE and non-distressing PLE groups (F values: 2.3-2.8; p values: < 0.005). Receptive language (β = 0.24, p = 0.03) and delayed recall (β = - 0.17, p = 0.02) predicted PLE distress severity. In Study 2, the cognitive-developmental variables did not significantly predict PLE distress severity (β values = 0.01-0.22, p values: > 0.05).

CONCLUSION

Findings may be consistent with a cognitive-developmental model relating distressing PLEs in youth with difficulties in cognitive functioning. This highlights the potential utility of adjunctive cognitive strategies which target mechanisms associated with PLE distress. These could be included in cognitive-behavioural interventions offered prior to the development of an at-risk mental state in mental health, educational or public health settings.

Predictors of isoniazid preventive therapy completion among adults newly diagnosed with HIV in rural Malawi

SETTING

To reduce the risk of tuberculosis (TB) among individuals with human immunodeficiency virus (HIV) infection, the World Health Organization recommends at least 6 months of isoniazid preventive therapy (IPT). Completion of IPT remains a major challenge in resource-limited settings.

OBJECTIVE

To evaluate predictors of IPT completion in individuals newly diagnosed with HIV.

DESIGN

Predictors of IPT completion among adults newly diagnosed with HIV in rural Malawi were evaluated using a multilevel logistic regression model.

RESULTS

Of 974 participants who screened negative for active TB and were started on IPT, 732 (75%) completed treatment. Only one IPT-eligible individual refused treatment. Participants who were aged <25 years (compared with those aged 45 years, adjusted OR [aOR] 0.33, 95%CI 0.18-0.60) and male (compared to non-pregnant females, aOR 0.57, 95%CI 0.37-0.88) had lower odds of IPT completion.

CONCLUSION

IPT provision at the time of initial HIV diagnosis was highly acceptable in rural Malawi; three quarters of those who initiated IPT successfully completed therapy. We observed lower odds of completion among males and among female participants aged <25 years. Additional efforts may be needed to ensure IPT completion among males and young females who have recently been diagnosed with HIV.

Delay in seeking care for tuberculosis symptoms among adults newly diagnosed with HIV in rural Malawi

SETTING:

Ten primary health clinics in rural Thyolo District, Malawi.

OBJECTIVE :

Tuberculosis (TB) is a common initial presentation of human immunodeficiency virus (HIV) infection. We investigated the time from TB symptom onset to HIV diagnosis to describe TB health-seeking behaviour in adults newly diagnosed with HIV.

DESIGN :

We asked adults (⩾18 years) about the presence and duration of TB symptoms at the time of receiving a new HIV diagnosis. Associations with delayed health seeking (defined as >30 and >90 days from the onset of TB symptoms) were evaluated using multivariable logistic regression.

RESULTS :

TB symptoms were reported by 416 of 1265 participants (33%), of whom 36% (150/416) had been symptomatic for >30 days before HIV testing. Most participants (260/416, 63%) were below the poverty line (US$0.41 per household member per day). Patients who first sought care from informal providers had an increased odds of delay of >30 days (adjusted odds ratio [aOR] 1.6, 95%CI 0.9–2.8) or 90 days (aOR 2.0, 95%CI 1.1–3.8).

CONCLUSIONS :

Delayed health seeking for TB-related symptoms was common. Poverty was ubiquitous, but had no clear relationship to diagnostic delay. HIV-positive individuals who first sought care from informal providers were more likely to experience diagnostic delays for TB symptoms.

Two-stage activity-safety study of daily rifapentine during intensive phase treatment of pulmonary tuberculosis

BACKGROUND

Rifapentine (RPT) has potent activity against Mycobacterium tuberculosis; however, the optimal dose for anti-tuberculosis treatment is unknown.

OBJECTIVE

To determine the antimicrobial activity, safety and tolerability of RPT 450 mg or 600 mg administered daily during the first 8 weeks of treatment for pulmonary tuberculosis (TB).

DESIGN

In a two-stage, randomised open-label study, adults with sputum smear-positive TB were randomised to receive RPT 450 mg, RPT 600 mg or rifampicin (RMP) 600 mg daily for 8 weeks with isoniazid, pyrazinamide and ethambutol. The primary endpoint was sputum culture status on Löwenstein-Jensen (LJ) medium at completion of 8 weeks of treatment.

RESULTS

A total of 153 participants were enrolled. Both RPT regimens met pre-specified criteria to advance to stage 2. At completion of 8 weeks of treatment, LJ culture conversion occurred in 85% (35/41), 96% (43/45) and 94% (34/36) of participants in the RPT 450 mg, RPT 600 mg and RMP groups, respectively. The proportions of participants discontinuing treatment were similar (respectively 1/54 [2.0%], 1/51 [2.0%] and 4/48 [8.3%] in the RPT 450 mg, RPT 600 mg and RMP groups), as were ⩾grade 3 adverse events (0/54 [0%], 1/51 [2.0%] and 4/48 [8.3%]).

CONCLUSIONS

There was a trend towards greater efficacy with RPT 600 mg than with RPT 450 mg. Daily RPT was safe and well-tolerated.

Community-randomized trial of enhanced DOTS for tuberculosis control in Rio de Janeiro, Brazil

SETTING

Central Rio de Janeiro, Brazil.

OBJECTIVE

To compare the impact of routine DOTS vs. enhanced DOTS (DOTS-Ampliado or DOTS-A) on tuberculosis (TB) incidence.

DESIGN

Cluster-randomized trial in eight urban neighborhoods pair-matched by TB incidence and randomly assigned to receive either the DOTS-A or DOTS strategy. DOTS-A added intensive screening of household contacts of active TB cases and provision of treatment to secondary cases and preventive therapy to contacts with latent TB infection (LTBI) to the standard DOTS strategy. The primary endpoint was the TB incidence rates in communities after 5 years of intervention.

RESULTS

From November 2000 to December 2004, respectively 339 and 311 pulmonary TB cases were enrolled and 1003 and 960 household were identified in DOTS and DOTS-A communities. Among contacts from DOTS-A communities, 26 (4%) had active TB diagnosed and treated, 429 (61.3%) had LTBI detected and 258 (60.1%) started preventive therapy. TB incidence increased by 5% in DOTS communities and decreased by 10% in DOTS-A communities, for a difference of 15% after 5 years (P = 0.04).

CONCLUSION

DOTS-A was associated with a modest reduction in TB incidence and may be an important strategy for reducing the burden of TB.

The aetiology of diarrhoea in newborn infants

Diarrhoea is a common problem in newborn infants in hospital nurseries. In the past, sporadic diarrhoea was often attributed to dietary indiscretion by the mother, and epidemic diarrhoea was though to be caused by an unknown infectious agent. Techniques with which to locate non-cultivable viruses and untypable enteropathogenic strains of Escherichia coli allow reevaluation of the aetiology of diarrhoea in newborn infants. Preliminary results from Melbourne, Australia, suggest that most diarrhoea in newborn infants is induced by a specific infectious agent. During 1975 the agent most often identified from sporadic and epidemic diarrhoea in hospital nurseries was a reovirus-like particle ("duovirus"). Enterotoxin-producing strains of E. coli were rarely isolated. Future attempts to protect newborn infants from developing diarrhoea must be based on an accurate understanding of the aetiology of this disease.

Regulatory roles of Runx2 in metastatic tumor and cancer cell interactions with bone

The three mammalian Runt homology domain transcription factors (Runx1, Runx2, Runx3) support biological control by functioning as master regulatory genes for the differentiation of distinct tissues. Runx proteins also function as cell context-dependent tumor suppressors or oncogenes. Abnormalities in Runx mediated gene expression are linked to cell transformation and tumor progression. Runx2 is expressed in mesenchymal linage cells committed to the osteoblast phenotype and is essential for bone formation. This skeletal transcription factor is aberrantly expressed at high levels in breast and prostate tumors and cells that aggressively metastasize to the bone environment. In cancer cells, Runx2 activates expression of bone matrix and adhesion proteins, matrix metalloproteinases and angiogenic factors that have long been associated with metastasis. In addition, Runx2 mediates the responses of cells to signaling pathways hyperactive in tumors, including BMP/TGFbeta and other growth factor signals. Runx2 forms co-regulatory complexes with Smads and other co-activator and co-repressor proteins that are organized in subnuclear domains to regulate gene transcription. These activities of Runx2 contribute to tumor growth in bone and the accompanying osteolytic disease, established by interfering with Runx2 functions in metastatic breast cancer cells. Inhibition of Runx2 in MDA-MB-231 cells transplanted to bone decreased tumorigenesis and prevented osteolysis. This review evaluates evidence that Runx2 regulates early metastatic events in breast and prostate cancers, tumor growth, and osteolytic bone disease. Consideration is given to the potential for inhibition of this transcription factor as a therapeutic strategy upstream of the regulatory events contributing to the complexity of metastasis to bone.

Tumor necrosis factor alpha (TNF-alpha) coordinately regulates the expression of specific matrix metalloproteinases (MMPS) and angiogenic factors during fracture healing

Recent studies from our laboratory demonstrate that TNF-alpha signaling contributes to the regulation of chondrocyte apoptosis and a lack of TNF-alpha signaling leads to a persistence of cartilaginous callus and delayed resorption of mineralized cartilage. This study examines how delays in the endochondral repair process affect the expression of specific mediators of proteolytic cartilage turnover and vascularization. Simple closed fractures were produced in wild type and TNF-alpha receptor (p55-/-/p75-/-)-deficient mice. Using ribonuclease protection assay (RPA) and microarray analysis, the expression of multiple mRNAs for various angiogenic factors and the metalloproteinase gene family were measured in fracture calluses. The direct actions of TNFalpha on the expression of specific angiogenic factors and metalloproteinases (MMPs) was examined in both cultured callus cells and articular chondrocytes to compare the effects of TNF-alpha in growth cartilage versus articular cartilage. MMPs 2, 9, 13, and 14 were quantitatively the most prevalent metalloproteases and all showed peaks in expression during the chondrogenic period. In the absence of TNF-alpha signaling, the expression of all of these mRNAs was reduced. The angiopoietin families of vascular regulators and their receptors were expressed at much higher levels than the VEGFs and their receptors and while the angiopoietins showed diminished or delayed expression in the absence of TNF-alpha signaling, VEGF and its receptors remained unaltered. The expression of vascular endothelial growth inhibitor (VEGI or TNFSF15) showed a near absence in its expression in the TNF-alpha receptor-deficient mice. In vitro assessment of cultured fracture callus cells in comparison to primary articular chondrocytes showed that TNF-alpha treatment specifically induced the expression of MMP9, MMP14, VEGI, and Angiopoietin 2. These results suggest that TNF-alpha signaling in chondrocytes controls vascularization of cartilage through the regulation of angiopoietin and VEGI factors which play counterbalancing roles in the induction of growth arrest, or apoptosis in endothelial cells. Furthermore, TNF-alpha appears to regulate, in part, the expression of two key proteolytic enzymes, MMP 9 and MMP14 that are known to be crucial to the progression of vascularization and turnover of mineralized cartilage. Thus, TNF-alpha signaling in healing fractures appears to coordinate the expression of specific regulators of endothelial cell survival and metalloproteolytic enzymes and is essential in the transition and progression of the endochondral phase of fracture repair.

Osteogenic differentiation is selectively promoted by morphogenetic signals from chondrocytes and synergized by a nutrient rich growth environment

Cartilage formation always precedes that of bone during endochondral skeletal development. To determine if chondrocytes provide inductive signals for osteogenesis, C3H10T(1/2) mesenchymal stem cells were co-cultured in membrane separated transwell culture chambers with chondrocytes, osteoblasts, or fibroblasts. Osteogenesis, as assessed by the expression of osteocalcin mRNAs, was strongly induced in the C3H10T(1/2) cells co-cultured with chondrocytes but not induced by co-culture with either osteoblasts or fibroblasts. Interestingly, while only osteogenic differentiation was observed in the C3H10T(1/2) cells co-cultured with chondrocytes, bone morphogenetic protein (BMP)-7 treatment induced an ordered endochondral progression of skeletal cell differentiation in which chondrogenic differentiation preceded osteogenesis by 2 to 4 days. A nutrient enriched growth environment enhanced osteogenic differentiation induced by either co-culture or BMP-7 treatment 2- to 5-fold. Nutrient enhanced osteogenic differentiation was associated with an activation of the retinoblastoma-mediated signal transduction pathways. In summary, these results show that osteogenesis is selectively induced by morphogenetic signals produced by chondrocytes and that a nutrient rich environment enhances both BMP-7- and co-culture-induced osteogenic differentiation.

Putting the 'informed' into 'consent': a matter of plain language

Health professionals frequently write at the same level for lay readers as they write for peers. In relation to health research and ethical requirements to provide written explanation of studies, this can complicate the notion of informed consent. Plain language information statements need to be clearly understood by research subjects if the ethics process for research approval is to fulfil its objective. Many delays in gaining ethics approval for child-related research are caused by substandard plain language statements (PLS). We describe specific issues for information statements for research with children, young people and their parents/guardians, particularly in consideration of the literacy capabilities of the general population. We highlight the usefulness of everyday language when explaining research and science in writing to families, and present some guidelines for writing PLS that have emerged from the introduction of a plain language service by an Ethics in Human Research Committee.

Impaired fracture healing in the absence of TNF-alpha signaling: the role of TNF-alpha in endochondral cartilage resorption

TNF-alpha is a major inflammatory factor that is induced in response to injury, and it contributes to the normal regulatory processes of bone resorption. The role of TNF-alpha during fracture healing was examined in wild-type and TNF-alpha receptor (p55(-/-)/p75(-/-))-deficient mice. The results show that TNF-alpha plays an important regulatory role in postnatal endochondral bone formation.

INTRODUCTION

TNF-alpha is a major inflammatory factor that is induced as part of the innate immune response to injury, and it contributes to the normal regulatory processes of bone resorption.

METHODS

The role of TNF-alpha was examined in a model of simple closed fracture repair in wild-type and TNF-alpha receptor (p55(-/-)/p75(-/-))-deficient mice. Histomorphometric measurements of the cartilage and bone and apoptotic cell counts in hypertrophic cartilage were carried out at multiple time points over 28 days of fracture healing (n = 5 animals per time point). The expression of multiple mRNAs for various cellular functions including extracellular matrix formation, bone resorption, and apoptosis were assessed (triplicate polls of mRNAs).

RESULTS AND CONCLUSIONS

In the absence of TNF-alpha signaling, chondrogenic differentiation was delayed by 2-4 days but subsequently proceeded at an elevated rate. Endochondral tissue resorption was delayed 2-3 weeks in the TNF-alpha receptor (p55(-/-)/p75(-/-))-deficient mice compared with the wild-type animals. Functional studies of the mechanisms underlying the delay in endochondral resorption indicated that TNF-alpha mediated both chondrocyte apoptosis and the expression of proresorptive cytokines that control endochondral tissue remodeling by osteoclasts. While the TNF-alpha receptor ablated animals show no overt developmental alterations of their skeletons, the results illustrate the primary roles that TNF-alpha function contributes to in promoting postnatal fracture repair as well as suggest that processes of skeletal tissue development and postnatal repair are controlled in part by differing mechanisms. In summary, these results show that TNF-alpha participates at several functional levels, including the recruitment of mesenchymal stem, apoptosis of hypertrophic chondrocytes, and the recruitment of osteoclasts function during the postnatal endochondral repair of fracture healing.

Direct measurement of the preferred sense of NO rotation after collision with argon

The preferred sense of product molecule rotation (clockwise or counterclockwise) in a bimolecular collision system has been measured. Rotationally inelastic collisions of nitric oxide (NO) molecules with Ar atoms were studied by combining crossed molecular beams, circularly polarized resonant multiphoton ionization probing, and velocity-mapped ion imaging detection. The observed sense of NO product rotation varies with deflection angle and is a strong function of the NO final rotational state. The largest preferences for sense of rotation are observed at the highest kinematically allowed product rotational states; for lower rotational states, the variation with deflection angle becomes oscillatory. Quantum calculations on the most recently reported NO-Ar potential give good agreement with the observed oscillation patterns in the sense of rotation.

A randomized, controlled trial of interventions to improve adherence to isoniazid therapy to prevent tuberculosis in injection drug users

PURPOSE

To determine the effect of several interventions on adherence to tuberculosis preventive therapy.

METHODS

We conducted a randomized trial with a factorial design comparing strategies for improving adherence to isoniazid preventive therapy in 300 injection drug users with reactive tuberculin tests and no evidence of active tuberculosis. Patients were assigned to receive directly observed isoniazid preventive therapy twice weekly (Supervised group, n = 99), daily self-administered isoniazid with peer counseling and education (Peer group, n = 101), or routine care (Routine group, n = 100). Patients within each arm were also randomly assigned to receive an immediate or deferred monthly $10 stipend for maintaining adherence. The endpoints of the trial were completing 6 months of treatment, pill-taking as measured by self-report or observation, isoniazid metabolites present in urine, and bottle opening as determined by electronic monitors in a subset of patients.

RESULTS

Completion of therapy was 80% for patients in the Supervised group, 78% in the Peer group, and 79% in the Routine group (P = 0.70). Completion was 83% (125 of 150) among patients receiving immediate incentives versus 75% (112 of 150) among patients with deferred incentives (P = 0.09). The proportion of patients who were observed or reported taking at least 80% of their doses was 82% for the Supervised arm of the study, compared with 71% for the Peer arm and 90% for the Routine arm. The proportion of patients who took 100% of doses was 77% for the Supervised arm (by observation), 6% for the Peer arm (by report), and 10% for the Routine arm (by report; P <0.001). Direct observation showed the median proportion of doses taken by the Supervised group was 100%, while electronic monitoring in a subset of patients showed the Peer group (n = 27) took 57% of prescribed doses and the Routine group (n = 32) took 49% (P <0.001). Patients in the Routine arm overreported adherence by twofold when data from electronic monitoring were used as a gold standard. There were no significant differences in electronically monitored adherence by type of incentive.

CONCLUSION

Adherence to isoniazid preventive therapy by injection drug users is best with supervised care. Peer counseling improves adherence over routine care, as measured by electronic monitoring of pill caps, and patients receiving peer counseling more accurately reported their adherence. More widespread use of supervised care could contribute to reductions in tuberculosis rates among drug users and possibly other high-risk groups.

runt homology domain transcription factors (Runx, Cbfa, and AML) mediate repression of the bone sialoprotein promoter: evidence for promoter context-dependent activity of Cbfa proteins

Expression of the bone sialoprotein (BSP) gene, a marker of bone formation, is largely restricted to cells in mineralized tissues. Recent studies have shown that the Cbfa1 (also known as Runx2, AML-3, and PEBP2alphaA) transcription factor supports commitment and differentiation of progenitor cells to hypertrophic chondrocytes and osteoblasts. This study addresses the functional involvement of Cbfa sites in expression of the Gallus BSP gene. Gel mobility shift analyses with nuclear extracts from ROS 17/2.8 osteoblastic cells revealed that multiple Cbfa consensus sequences are functional Cbfa DNA binding sites. Responsiveness of the 1.2-kb Gallus BSP promoter to Cbfa factors Cbfa1, Cbfa2, and Cbfa3 was assayed in osseous and nonosseous cells. Each of the Cbfa factors mediated repression of the wild-type BSP promoter, in contrast to their well known activation of various hematopoietic and skeletal phenotypic genes. Suppression of BSP by Cbfa factors was not observed in BSP promoters in which Cbfa sites were deleted or mutated. Expression of the endogenous BSP gene in Gallus osteoblasts was similarly downregulated by forced expression of Cbfa factors. Our data indicate that Cbfa repression of the BSP promoter does not involve the transducin-like enhancer (TLE) proteins. Neither coexpression of TLE1 or TLE2 nor the absence of the TLE interaction motif of Cbfa1 (amino acids 501 to 513) influenced repressor activity. However, removal of the C terminus of Cbfa1 (amino acids 362 to 513) relieved suppression of the BSP promoter. Our results, together with the evolutionary conservation of the seven Cbfa sites in the Gallus and human BSP promoters, suggest that suppressor activity by Cbfa is of significant physiologic consequence and may contribute to spatiotemporal expression of BSP during bone development.

Epidemiological patterns of rotaviruses causing severe gastroenteritis in young children throughout Australia from 1993 to 1996

Rotavirus strains that caused severe diarrhea in 4,634 (2,533 male) children aged less than 5 years and admitted to major hospitals in eight centers throughout Australia from 1993 to 1996 were subject to antigenic and genetic analyses. The G serotypes of rotaviruses were identified in 81.9% (3,793 of 4,634) children. They included 67.8% (from 3,143 children) serotype G1 isolates (containing 46 electropherotypes), 11.5% (from 531 children) serotype G2 isolates (27 electropherotypes), 0.8% (from 39 children) serotype G3 isolates (8 electropherotypes), and 1.6% (from 76 children) serotype G4 isolates (9 electropherotypes). G6 (two strains) and G8 (two strains) isolates were identified during the same period. G1 serotypes were predominant in all centers, with intermittent epidemics of G2 serotypes and sporadic detection of G3 and G4 strains. With the exception of two strains (typed as G1P2A[6] and G2P2A[6]) all serotype G1, G3, and G4 strains were P1A[8] and all serotype G2 strains were P1B[4]. Two contrasting epidemiological patterns were identified. In all temperate climates rotavirus incidence peaked during the colder months. The genetic complexity of strains (as judged by electropherotype) was greatest in centers with large populations. Identical electropherotypes appeared each winter in more than one center, apparently indicating the spread of some strains both from west to east and from east to west. Centers caring for children in small aboriginal communities showed unpredictable rotavirus peaks unrelated to climate, with widespread dissemination of a few rotavirus strains over distances of more than 1,000 km. Data from continued comprehensive etiological studies of genetic and antigenic variations in rotaviruses that cause severe disease in young children will serve as baseline data for the study of the effect of vaccination on the incidence of severe rotavirus disease and on the emergence of new strains.

Cost effectiveness of rotavirus vaccination in Australia

OBJECTIVE

Rotavirus gastroenteritis causes substantial morbidity, including hospital admission, in young children. In the context of recent vaccine developments, this study aimed to estimate the cost-effectiveness of a rotavirus vaccination program in Australia.

METHOD

Standard methods of health economic evaluation were used to assess the total cost of rotavirus immunisation (as the difference between estimated vaccination program costs and the cost of disease that would be avoided by immunisation) and relate this to the number of cases of disease that would be prevented. Estimates were made from both societal and health care systems perspectives.

RESULTS

Based on Australian data on disease incidence and cost of hospitalisation, the current annual cost of rotavirus disease is about $26.0 million. Using conservative vaccine efficacy estimates, current immunization uptake rates and a cost of $30 per dose of vaccine, rotavirus immunisation would incur a net societal cost of $2.9 million ($11 per child), at a gross program cost of $21.6 million. These estimates are sensitive to two sources of uncertainty in the estimation of program delivery costs: vaccine price and whether separate immunization visits would be required.

CONCLUSION

A rotavirus immunisation program would be cost-neutral to Australian society at a vaccine price of $26 per dose (or $19 when health care system costs only are considered).

IMPLICATIONS

Rotavirus immunization may be cost-effective in Australia, but considerable uncertainty remains. Policy decisions will depend heavily on pricing of the vaccine and may also need to consider intangible costs not accounted for in this analysis.

Etiology of acute gastroenteritis in hospitalized children in Melbourne, Australia, from April 1980 to March 1993

Acute infectious diarrhea is common in children. Control requires knowledge of causes. Few comprehensive long-term studies of etiology have been undertaken in developed countries. This report is of a 13-year survey of 4,637 children from 0 to 14 years of age, admitted to a large children's hospital for treatment of gastroenteritis, in which viruses, bacteria, and parasites were sought. A recognized enteric pathogen was identified in 56.6% of children. Group A rotaviruses occurred in 39.6% of children overall and in 55% of children 12 to 23 months of age. They were a frequent cause (18.7%) of acute gastroenteritis in children under 6 months and in those aged 5 to 13 years (16%). Rotaviruses were almost entirely responsible for winter admission peaks. Enteric adenovirus types 40 and 41 (6% overall) were more frequent in children under 12 months (9.4%). Salmonella spp. (5.8%) and Campylobacter jejuni (3.4%) were more common in children over 5 years (13.1% and 6.7%, respectively). The 43.5% of cases (60% in children under 6 months) where no enteric pathogen was identified are cause for concern. The involvement of small viruses (including caliciviruses and astroviruses) may be clarified when molecular biology techniques are utilized to address this gap in our knowledge. This comprehensive 13-year study of the cause of acute infectious diarrhea in children in developed countries reinforces the importance of rotavirus and highlights a large group for whom the etiology remains unknown, an issue of particular concern with babies under 6 months of age. New techniques have the potential to identify old and new pathogens causing disease in these vulnerable infants.

Cloning and characterization of chicken Paraxis: a regulator of paraxial mesoderm development and somite formation

To investigate the molecular regulation of embryonic somite formation and development, we have cloned the full-length cDNA and characterized the embryonic expression profile of chicken Paraxis, a member of a novel family of basic helix-loop-helix (bHLH) proteins, which has been suggested to play a role in paraxial mesoderm development. Chicken Paraxis encodes a 1.35-kb mRNA and contains a 53-amino-acid residue bHLH domain, identical in sequence to that found in the mammalian Paraxis genes of mouse, hamster, and human. Northern analysis revealed significant Paraxis expression in the early embryo up to the 30- to 35-somite stage, declining from Incubation Day 4 on and becoming undetectable by Day 5. By whole-mount in situ hybridization, Paraxis expression is first seen distinctly in the emerging paraxial mesoderm of the primitive streak stage chick embryo. During gastrulation, Paraxis expression in the mesoderm defines bilaterally symmetric crescents located immediately rostral to Hensen's node and appears to pre-configure the emerging somitic mesoderm. During somite development, Paraxis expression is evident in the rostral segmental plate and the newly formed somites, although the level of expression clearly decreases in the more mature somites. By the 10-12th pair of somites, counting from the caudal end, Paraxis expression appears to be preferentially localized to the medial aspect of individual somites. Histological analysis showed that Paraxis expression is evenly distributed in the newly formed caudal epithelial somites, then localized to the medial portion of maturing somites, and preferentially localized in the dermomyotome of more rostral somites before diminishing to undetectable levels in the most cranial somites. The functional involvement of Paraxis in somite development was assessed by perturbing its expression in somitic stage chick embryos using a Paraxis-specific antisense oligonucleotide. Disruption of somite formation from the paraxial mesoderm was observed in 67% of the surviving topically treated embryos, whereas control embryos treated with sense or random sequence oligonucleotides did not show similar effects. In addition, direct injection of Paraxis-specific antisense oligonucleotide into the paraxial mesoderm produced discrete segmentation anomalies which correlated spatially with the site of injection. Whole-mount in situ hybridization revealed that the regions defective in somite formation displayed perturbed Paraxis expression and a reduction of Pax-1 expression, a marker for epithelial somites and sclerotome. Histological analysis indicated poor condensation and/or epithelization of the somitic mesoderm. Finally, embryos treated with valproic acid, a known teratogen which affects somite segmentation, showed perturbed Paraxis expression, suggesting that the mechanism of action of this teratogen involves a pathway(s) requiring Paraxis activity. These data provide evidence that Paraxis acts as an important regulator of paraxial mesoderm and somite development and functions in axial patterning of the chick embryo.

Phase 1 trial of a candidate rotavirus vaccine (RV3) derived from a human neonate

OBJECTIVE

To conduct a phase 1 safety and tolerability trial of an oral rotavirus vaccine candidate RV3 in healthy volunteers.

METHODOLOGY

Double blind placebo controlled trial of a single 1 mL oral dose (6.5 x 10(5) fluorescing focus units [FFU]/mL) in 10 healthy young men, 10 3-4 year old children and 10 3 month old infants with a 4 week surveillance period. The study was undertaken at a children's hospital and nearby community in Melbourne, Australia.

RESULTS

All subjects successfully completed the trial. There were no significant side-effects attributable to the vaccine preparation in any age group. No shedding of vaccine virus was detected by enzyme immunoassay. There was evidence of an immune response in serum and/or gut secretions in two of five vaccinees in each age group.

CONCLUSION

RV3 rotavirus vaccine appears to be safe and well tolerated. Evidence of immunogenicity in some subjects after a single dose encourages further trials to determine immunogenicity after three doses, after reduction of viral dose, and without prior administration of buffer.

Rotavirus infection and prevention

The major advance in knowledge about rotavirus infection and prevention has been in vaccine development. Several large studies of tetravalent rhesis rotavirus vaccine have had encouraging results, and a first-generation vaccine is likely to be licensed by the 25th anniversary of the discovery of rotavirus (in 1973). Epidemiologic studies have highlighted a diversity of less common G types and non-group A strains, observations to be taken into account in further vaccine development. Disconcerting anecdotal reports of central nervous system involvement need to be cautiously interpreted. New information on pathophysiology raises the intriguing concept of viral toxin involvement. Oral immunoglobulin has been used for prophylaxis and also for treatment during active infection.

Chicken Pax-1 gene: structure and expression during embryonic somite development

Recent mouse genetic studies have implicated Pax-1, a paired-box-containing gene, in sclerotomal differentiation and vertebral body formation. To investigate Pax-1 function in somitic sclerotomal differentiation in the chick embryo, we have cloned the chicken Pax-1 gene, and its full length cDNA, and characterized its temporal and spatial expression pattern during somite development. Sequence analysis shows that chicken Pax-1 is highly homologous to murine and human Pax-1 genes with respect to the putative DNA-binding paired-box domain and the octapeptide domain. Northern analysis using probes derived from the paired-box domain and a unique non-paired box sequence of chicken Pax-1 detected 2-kb mRNA transcript. The expression profiles of Pax-1 were examined by in situ hybridization and Northern analysis. The first detectable expression of Pax-1 is seen in the most caudal epithelial somite. As the somite matures, Pax-1 expression takes on a medial distribution, thus corresponding to but preceding the emergence of the sclerotome. In the more mature, rostral somites (stage V and older), Pax-1 expression is found to be progressively localized first to the ventral-medial regions, and then to the caudal-ventral-medial quadrant of the mature somite. This pattern strongly supports the notion that Pax-1 expression is involved in somitogenesis and sclerotomal differentiation, and that it is subsequently a characteristic of the caudal half of the sclerotome, the presumptive precursor of vertebral cartilage. Northern analysis substantiated this expression profile and further revealed that the level of somitic Pax-1 expression increases as a function of embryonic development. Finally, we subjected chicken embryos to controlled heat shock treatment to perturb somite formation and segmentation. The pattern of Pax-1 expression in the anomalous somitic structures generated by controlled heat shock further supports a functional role for Pax-1 in somite development.

Serum, fecal, and breast milk rotavirus antibodies as indices of infection in mother-infant pairs

Sixty-eight mother-infant pairs were followed for 12-17 months after birth. Rotavirus infections in children were detected by EIA of weekly fecal antigen and anti-rotavirus IgA levels, by EIA of anti-rotavirus IgG in sera at birth, 6, or 12-17 months of age, and by anti-rotavirus EIA IgA and neutralizing antibody (NA) in monthly samples of maternal breast milk. Primary rotavirus infection was detected in 26 children (in 15 [58%] by fecal excretion, 12 [46%] by IgG seroconversion, and 22 [85%] by elevations of IgA anti-rotavirus antibodies [IgA coproconversion] in consecutive fecal specimens). Rotavirus "challenge" was detected by rises in levels of NA in breast milk in 9 (47%) of 19 mothers, including 5 (26%) from pairs in which there was no other evidence of rotavirus infection. Reinfections were detected in 2 children by rotavirus excretion and in 4 by coproconversion. IgA coproconversion is the most sensitive technique for detection of symptomatic and asymptomatic rotavirus infection in young children.

Valproic acid-induced somite teratogenesis in the chick embryo: relationship with Pax-1 gene expression

The repeated pattern of the axial skeleton results from the segmentation and re-segmentation of the mesodermally derived somites. During these early events of somite development, the vertebrate embryonic axial skeleton is most susceptible to the teratogenic effects of a variety of pharmaceutical and environmental agents. One example is the anticonvulsant drug valproic acid (VPA), which has been shown to cause craniofacial and minor and major skeletal defects in human and animal embryos. We hypothesize that a candidate set of molecular targets of teratogens are the Pax family of pattern-forming genes, specifically Pax-1, which has been previously demonstrated to be an important regulator of axial skeletal patterning at the somite level. In this study, early developmental stage chick embryos were treated with VPA and dose-dependent malformations in somite development were observed. Two classes of anomalies were evident: class I included discrete sites of somitic fusions or mis-segmentation, and Class II included large areas of disorganized somite patterning. Northern blot analysis revealed a decreased level of Pax-1 expression in VPA-treated embryos. Whole mount in situ hybridization analysis showed that somite anomalies correlate spatially with regions of decreased Pax-1 expression. Finally, comparison of the VPA-induced somitic anomalies with those caused by gene-specific perturbation of Pax-1 gene expression through the use of an antisense oligonucleotide revealed significant similarities. Taken together, these results support the hypothesis that Pax-1 is a molecular target in VPA axial skeletal teratogenicity.

Multiple-gene rotavirus reassortants responsible for an outbreak of gastroenteritis in central and northern Australia

Two rotavirus strains, E210 and E212, implicated in epidemics of gastroenteritis in children in central and northern Australia during 1993-1994, exhibited the unusual combination of a 'short' RNA electrophoretic pattern and subgroup II specificity. The outer capsid protein VP7 was found by PCR typing and sequence analysis to be related to that of serotype G2 viruses. Both strains displayed a novel pattern of reactivity to G2-specific monoclonal antibodies that correlated with sequence variation in the antigenic regions of VP7. The VP4 serotype of E210 and E212 was determined as P1B in an enzyme immunoassay, consistent with other G2 viruses. Analysis of the VP6 gene indicated significant identity (98-99%) with other human subgroup II viruses. Northern hybridization analysis of E210 RNA using total genome probes derived from the prototype strains RV4 and RV5 indicated that E210 was derived from multiple gene reassortment between rotaviruses belonging to different genetic types.

Histidine-rich protein B of embryonic feathers is present in the transient embryonic layers of scutate scales

Based on its amino acid composition and N-terminal sequence, a polypeptide (HRP-B) has been identified as a member of the avian histidine-rich protein (HRP) family. An antiserum against HRP-B has been used to localize this polypeptide in developing feathers and scales of chick embryos. HRP-B was first detectable in the barb ridge cells of feathers at 13 days of incubation and progressively appeared in the distal/proximal and peripheral/central gradients observed previously for the feather-type beta keratins in developing feathers. The HRP-B polypeptide was detected only in the embryonic layers of scutate scales. It first appeared at 16 days of incubation and was not found in the differentiated beta strata of these scales. At no time during the development of reticulate scales or apteric skin regions did the epidermal cells or cells of the embryonic layers express HRP-B. The transient expression of HRP-B by the embryonic layers of the scutate scale epidermis is discussed in light of the feather-forming potential of the presumptive epidermis of the scutate scale-forming region.

Patients with enteric adenovirus gastroenteritis admitted to an Australian pediatric teaching hospital from 1981 to 1992

During the period 1981 to 1992, 4,473 fecal specimens collected from children hospitalized with acute gastroenteritis at the Royal Children's Hospital, Melbourne, Australia, were examined by electron microscopy. A monoclonal antibody enzyme immunoassay for enteric adenovirus (EAd) types 40 (Ad40) and 41 (Ad41) was used when adenoviruses were visualized. Fecal samples were positive for adenovirus by both electron microscopy and enzyme immunoassay in 138 patients (3.1%). Ad40 was identified in 19 children (14%), and Ad41 was identified in 119 children (86%). These EAd were identified during each of the 12 years surveyed. EAd were present year-round, but the annual number of hospitalizations was not constant. Yearly prevalence varied from 0.7% (1981) to 6.5% (1985). This was associated with monthly fluctuations in Ad41 activity, with overall peak monthly prevalence in May (late autumn). By contrast, Ad40 numbers remained low and constant year-round. The frequency of Ad41 relative to Ad40 increased from 25% in 1981 to exceed 75% after 1983. Children admitted with EAd infection were more likely to have diarrhea for more than 5 days (P < 0.001) but less likely to be febrile or dehydrated (P < 0.05) than children with rotavirus infection. EAd are responsible for enteric symptoms of only a fraction of hospitalized children with infectious diarrhea but result in a more-protracted illness than rotavirus. Their relationship to persistent diarrhea requires further investigation.

Plant sources of acid stable lipases: potential therapy for cystic fibrosis

Exogenous lipase used in the treatment of pancreatic insufficiency may be destroyed by stomach acid. This study was undertaken to search for a readily available source of acid stable lipase. Eleven plant sources (avocado, walnut, pinenut, coconut, lupin, lentils, chickpea, mungbean, oats, castor beans and eggplant) were screened for lipolytic activity using a newly developed radio-isotopic labelled substrate method. The results obtained by this method were confirmed by thin layer chromatography. Two of the sources (castor bean and dehulled oats) showed significant lipolytic activity at pH 5.6, castor beans containing 1.5 U/mg of extracted solid and oats 400-1200 U/mg of extracted solid. Castor beans are difficult to obtain and so may be an impractical commercial source of lipase; however, oats are abundant. If simple methods of enzyme purification and concentration can be developed, oats may prove to be a practical source of acid stable lipase for use in the treatment of patients with pancreatic insufficiency, especially those who have cystic fibrosis.

Is cow's milk protein intolerance a cause of gastro-oesophageal reflux in infancy?

To test the hypothesis that cow's milk protein intolerance (CMPI) might cause or contribute to gastro-oesophageal reflux (GOR), 10 of 14 infants with abnormal GOR on prolonged oesophageal pH monitoring who had failed to respond to conventional antireflux therapy were placed on a hypo-allergenic diet for 1 month. In no child was there significant improvement in pH monitoring indices, and only two showed any symptomatic improvement. Therefore, in these children, CMPI did not appear to contribute to GOR. It is probable that CMPI is rare as a cause of passive GOR, although our results do not exclude CMPI as a cause of active vomiting.

Rotavirus gastroenteritis in infants aged 0-6 months in Melbourne, Australia: implications for vaccination

The aim of this study was to determine the occurrence of rotavirus infection in infants under 6 months of age who were admitted to hospital in a developed country for treatment of gastroenteritis. Between April 1980 and April 1990, 595 such infants were admitted to the infectious diseases ward at the Royal Children's Hospital, Melbourne, Australia. Faecal specimens were collected within 6 h of admission and were tested for viral, bacterial and protozoal enteric pathogens. Rotaviruses of several serotypes were found in specimens from 15.1% of the infants, adenoviruses in 12.4% and other pathogens in 10.8%. Rotaviruses were found equally often in infants in each 1 month age group. No pathogens were able to be identified in 61.7% of cases. These results show that rotavirus is an important pathogen in infants under 6 months of age who are admitted to hospital with gastroenteritis. Rotavirus vaccination will need to be given during the first 1-3 months of life in developed countries, as is recommended for developing countries. The large group in whom no pathogens were isolated requires further consideration.

Region-specific patterns of beta keratin expression during avian skin development

The transient embryonic layers primarily composed of a periderm and subperiderm cover most regions of the chick embryo and are the first suprabasal cell layers covering the body ectoderm. This study presents evidence for regional variation in the expression of beta keratin in the embryonic layers. Here we show that the embryonic layers covering the anterior metatarsal region of the chicken hindlimb (scutate scale forming region) produce several members of the beta keratin family of polypeptides, designated beta (beta) 1-7. These specific polypeptides are later expressed in this region exclusively in the thick, cornified beta strata of mature scutate scales. In contrast to this sequence of events, the embryonic layers overlying the epidermis of the ventral foot pad (reticulate scale-forming region) and those covering the epidermis in apteric regions of the body produce beta keratin polypeptides beta 1-3 and beta 2,3, respectively, but no subsequent expression of these proteins occurs in the mature epidermises of these regions. Furthermore, we find that the embryonic layers of the skin overlying the anterior metatarsal region of birds homozygous for the mutation "scaleless" (sc/sc), which completely lack scutate scales, produce the same members of the beta keratin family, beta 1-7, as the embryonic layers and beta strata of normal scutate scales. Thus, the accumulation of specific beta keratin polypeptides in the developing anterior metatarsal region appears to occur in two distinct phases; first, an early region-specific expression in cells of the embryonic layers followed by a second phase of expression which occurs in conjunction with appendage morphogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of coproantibody in clinical protection of children during reinfection with rotavirus

Rotavirus is the major cause of severe, dehydrating infantile gastroenteritis. Infection is limited to the gut, but the relative roles of serum and secretory copro-immunoglobulin A (IgA) in protection are unclear. Specific copro-IgA is predictive of duodenal antirotaviral IgA and correlates with virus-neutralizing coproantibody. Copro-IgA conversion is a more sensitive marker of rotavirus reinfection than seroconversion. We measured rotavirus reinfections by copro-IgA conversion prospectively in 35 children recruited at a time of severe rotavirus illness. The children were followed up longitudinally for 14 to 31 months to determine whether high coproantibody levels correlated with clinical protection against rotavirus disease. Ninety-four percent of the children experienced reinfection, and 38% developed persistent elevations in specific copro-IgA termed plateaus. Plateau children had a higher mean annual rate of rotavirus infection and a lower ratio of symptomatic to total number of rotavirus reinfections than did nonplateau children. The annual rates of rotavirus infection and disease were significantly higher outside the plateau than inside it in children experiencing antirotavirus copro-IgA plateaus. Frequent rotavirus infection of children appears to stimulate production of a specific copro-IgA plateau which correlates with protection against an excess of infection and symptomatic disease.

Normalization of vitamin B12 absorption after ileal resection in children

Impaired Vitamin B12 absorption after significant ileal resection has been reported to be permanent, although partial recovery after ileal bypass can occur. Three children are presented in whom Vitamin B12 malabsorption returned to normal 6-8 years after ileal resection. This was due probably to adaptation of the remaining small bowel, although spontaneous resolution of bacterial overgrowth is a possible explanation. An abnormal Schilling test after ileal resection does not automatically imply the need for life-long Vitamin B12 injections.

Severity of rotavirus infection in relation to serotype, monotype and electropherotype

The aim of this study was to determine whether the severity of symptoms associated with rotavirus infection was related to the serotype of the infecting virus. Severity of clinical symptoms in 108 children admitted to hospital for treatment of rotavirus diarrhoea was retrospectively assessed using a scoring system for frequency and duration of vomiting and diarrhoea, degree of fever, acidosis and dehydration, and presence of electrolyte imbalance. Children were 6-30 months old and were fully weaned at onset of symptoms prior to admission to hospital. No other enteric pathogens were detected during the course of the illness. Serotypes and monotypes were identified using a panel of monoclonal antibodies. Gel electrophoresis of rotavirus RNA was performed to determine electropherotypes. Children surveyed were infected with serotype 1 (47), serotype 2 (15) or serotype 4 (46) rotaviruses. Comparisons of severity of clinical symptoms according to infecting serotype revealed no statistically significant differences between serotype 1, 2 or 4 infections. In addition, no differences were detected between different rotavirus strains within each serotype (as judged by electropherotype) including monotypes 1a or 1c. This study failed to reveal differences in virulence between rotavirus strains of different VP7 serotypes infecting young children.

Epidemiology of rotavirus serotypes in Melbourne, Australia, from 1973 to 1989

Fecal rotavirus strains collected between 1973 and 1989 from 943 children admitted with acute diarrhea to one hospital in Melbourne, Australia, were serotyped by using an enzyme-linked immunosorbent assay. The assay incorporated neutralizing monoclonal antibodies specific for VP7 of the four major human serotypes (1 through 4). A serotype could be assigned to 690 of 943 specimens (73.2%). Typeable strains comprised serotype 1 (72.5%), serotype 2 (6.8%), serotype 3 (2.9%), or serotype 4 (15.4%). Monotypes 1a and 1c comprised 52 and 44%, respectively, of serotype 1 strains. All serotypes and monotypes exhibited polymorphic genomic RNAs. Specimens reacting as mixed serotypes were rare (3.2%) and included intertypic strains (0.7%) and mixed infections (1.0%). Nontypeable strains for which an electropherotype could be determined appeared to be identical with typeable strains present concurrently in the community. Serotypes exhibited various epidemiological patterns. Serotype 1 strains were dominant except during three successive winters when 60 to 90% of the disease was caused by serotype 2. Serotype 4 strains showed an episodic pattern of appearance, recurring at peak incidence approximately every 3 years. Fecal rotavirus strains collected from 145 newborn babies housed in Melbourne obstetric hospitals between 1974 and 1986 were also serotyped. All 135 typeable strains (93.1%) belonged to serotype 3. It is hypothesized that endemic infection with serotype 3 rotaviruses in nurseries for the newborn influenced the epidemiology of rotavirus serotypes responsible for severe clinical disease in young children in the same community.

Comparison of rotavirus immunoglobulin A coproconversion with other indices of rotavirus infection in a longitudinal study in childhood

In order to determine the sensitivity and reliability of antirotaviral fecal immunoglobulin A (IgA) as an indicator of rotavirus reinfection, the antibody responses to rotavirus of 44 infants with severe rotavirus gastroenteritis recruited on admission to a hospital were studied. Feces were collected daily during hospitalization and weekly thereafter, and sera were obtained every 4 months, for 6 to 32 months (median, 17 months). Antirotaviral IgG, IgA, and IgM were measured by enzyme immunoassay in all samples. Rotavirus antigen, rotavirus-neutralizing antibody, and total IgA were measured in feces. The results showed that use of an IgA index (ratio of specific IgA to total IgA) was unnecessary to identify copro-IgA conversion to rotavirus. The other markers of rotavirus infection tested showed a high level of predictive accuracy of coproconversion in rotavirus-neutralizing antibody. Copro-IgM, serum IgM, and virus in feces were insensitive measures of neutralizing antibody coproconversion. Seroconversion in IgG or IgA was detected in 46% of neutralizing coproconversions. The most sensitive marker, present in 92% of neutralizing coproconversions, was antirotaviral fecal IgA conversion. This correlation of fecal IgA with fecal neutralizing antibody suggests that coproconversions in IgA represent true elevations in antirotaviral IgA with neutralizing capacity. A coproconversion in IgA appears to indicate genuine rotavirus infection. Copro-IgA conversions in feces collected weekly are likely to be more sensitive markers of rotavirus reinfection than are seroconversion and virus detection combined in epidemiological studies of acute diarrhea in children and in rotavirus vaccine trials.

Evaluation of end-point titration, single dilution and capture enzyme immunoassays for measurement of antirotaviral IgA and IgM in infantile secretions and serum

In order to facilitate measurement of antirotaviral IgA in large collections of faeces and secretions, adaptations of enzyme immunoassay methods for estimating antirotaviral IgA and IgM in duodenal fluid, saliva, faeces and serum were studied. To quantitate specific IgA, a single dilution of each sample was assayed. Results were expressed as antirotaviral IgA units derived from a standard curve. Units were calculated by log-logit analysis on computer. There was strong correlation between antirotaviral IgA units and end-point titres in 257 faecal samples (correlation coefficient r = 0.92) and in 182 duodenal fluids and salivary samples (correlation coefficient r = 0.74). The assay was validated using acute and convalescent faeces from children with or without rotavirus infection. Immune conversions in IgA were detected in 33 (75%) of the children by units and 34 (77%) by titres. None of nine children with gastroenteritis due to other infectious agents showed immune conversions to rotavirus. A monoclonal capture IgM assay showed similar end-point titres and numbers of immune conversions when compared with a direct assay for antirotaviral IgM in serum and secretions. Use of the capture method eliminated false-positive reactions with the cell control. The assay for antirotaviral IgA units in secretions is simple, rapid, reproducible and reliable, and has proven of value in longitudinal epidemiological studies of rotavirus coproIgA profiles. Both the capture IgM technique and the single dilution IgA method permit analysis of large numbers of specimens and are appropriate for examination of immune responses to natural rotavirus infection or during vaccine trials.

Rotavirus serotypes causing acute diarrhoea in hospitalized children in Yogyakarta, Indonesia during 1978-1979

Rotavirus strains in stool specimens from 111 children aged 3-24 months admitted to hospital in Yogyakarta, Indonesia for treatment of acute diarrhoea were serotyped using VP7 serotype specific monoclonal antibodies in a double sandwich enzyme immunoassay. A serotype could be assigned to 59 of 111 specimens (53%). Inability to assign a serotype to 47% of specimens was probably due to loss of the outer capsid during transport of specimens from Indonesia to Australia. All four major human rotavirus serotypes were detected during the 15 month survey from June 1978 to August 1979, including one serotype 1, 5 serotype 2, 31 serotype 3, and 21 serotype 4 strains. One additional strain reacted with serotype 3 and 4 Mabs. Serotype 3 strains showed intratypic variation. The relative frequency of serotypes 2, 3, and 4 varied during the 15 months and appeared to be influenced by climatic changes associated with dry and wet seasons. Vaccine strategies must take account of comparatively rapid changes of predominant serotypes in a community and are only likely to be successful if comprehensive immunity can be established simultaneously against the four major human serotypes.

Infectious diarrhea in children undergoing bone-marrow transplantation

Fecal flora of 12 children undergoing bone-marrow transplantation was monitored prospectively using comprehensive microbiological techniques. Diarrhea developed at least once in ten of the 12 children (83%), and a total of 24 episodes were recorded. Recognised gut pathogens were isolated from 11/21 (52%) diarrheal episodes where fecal specimens were obtained. Enteric pathogens identified included viral pathogens in 19% (rotaviruses, 'enteric' adenoviruses), parasites in 19% (cryptosporidium, Giardia lamblia) and cytotoxic C. difficile (14%). Excretion of clostridial species (including cytotoxin negative C. difficile, C. innocuum) occurred in 90% of diarrheal episodes when no enteric pathogen was identified. These results suggest that infection is often responsible for diarrhea associated with bone-marrow transplantation. Prophylaxis against enteric infection might reduce the morbidity and mortality associated with severe diarrhea in bone-marrow transplanted children.

Sweat testing by capillary collection and osmometry: suitability of the Wescor Macroduct System for screening suspected cystic fibrosis patients

A new method of collecting and analysing sweat (Wescor Macroduct) has advantages of simplicity of collection and direct reading of results by osmometry. Forty-seven children with cystic fibrosis and 47 normal children had sweat tests performed simultaneously by the Gibson and Cooke method and by the Wescor Macroduct method. The new method had a higher rate of inadequate collection (19% vs 6%) which was more marked in children under 5 years of age. This was due partly to the difficulty of fitting a 2.5 cm pilocarpine gel disc to small arms. When an adequate collection was obtained, results were reliable with no false negatives occurring during this study. The Wescor Macroduct sweat test is a reliable method for use in peripheral centres to screen patients suspected of having cystic fibrosis. All children with an inadequate collection or a positive result should be referred to a reference centre for confirmation of the diagnosis. However, the majority will be saved the expense and disruption of travel.