Clinical presentation, disease course, and outcome of COVID-19 in hospitalized patients with and without pre-existing cardiac disease: a cohort study across 18 countries

AIMS

Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality.

METHODS AND RESULTS

We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66-75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02-1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10-1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20-1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients.

CONCLUSION

Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

A rare variant in EZH2 is associated with prostate cancer risk

Prostate cancer (PrCa) is highly heritable, and although rare variants contribute significantly to PrCa risk, few have been identified to date. Herein, whole-genome sequencing was performed in a large PrCa family featuring multiple affected relatives spanning several generations. A rare, predicted splice site EZH2 variant, rs78589034 (G > A), was identified as segregating with disease in all but two individuals in the family, one of whom was affected with lymphoma and bowel cancer and a female relative. This variant was significantly associated with disease risk in combined familial and sporadic PrCa datasets (n = 1551; odds ratio [OR] = 3.55, P = 1.20 × 10^-5 ). Transcriptome analysis was performed on prostate tumour needle biopsies available for two rare variant carriers and two wild-type cases. Although no allele-dependent differences were detected in EZH2 transcripts, a distinct differential gene expression signature was observed when comparing prostate tissue from the rare variant carriers with the wild-type samples. The gene expression signature comprised known downstream targets of EZH2 and included the top-ranked genes, DUSP1, FOS, JUNB and EGR1, which were subsequently validated by qPCR. These data provide evidence that rs78589034 is associated with increased PrCa risk in Tasmanian men and further, that this variant may be associated with perturbed EZH2 function in prostate tissue. Disrupted EZH2 function is a driver of tumourigenesis in several cancers, including prostate, and is of significant interest as a therapeutic target.

Cerebral small vessel disease genomics and its implications across the lifespan

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were associated with altered white matter integrity (p = 2.5×10-7) in brain images from 1,738 young healthy adults, providing insight into the lifetime impact of SVD genetic risk. Mendelian randomization suggested causal association of increasing WMH-volume with stroke, Alzheimer-type dementia, and of increasing blood pressure (BP) with larger WMH-volume, notably also in persons without clinical hypertension. Transcriptome-wide colocalization analyses showed association of WMH-volume with expression of 39 genes, of which four encode known drug targets. Finally, we provide insight into BP-independent biological pathways underlying SVD and suggest potential for genetic stratification of high-risk individuals and for genetically-informed prioritization of drug targets for prevention trials.

Analysis of the F2LR3 (PAR4) Single Nucleotide Polymorphism (rs773902) in an Indigenous Australian Population

The F2RL3 gene encoding protease activated receptor 4 (PAR4) contains a single nucleotide variant, rs773902, that is functional. The resulting PAR4 variants, Thr120, and Ala120, are known to differently affect platelet reactivity to thrombin. Significant population differences in the frequency of the allele indicate it may be an important determinant in the ethnic differences that exist in thrombosis and hemostasis, and for patient outcomes to PAR antagonist anti-platelet therapies. Here we determined the frequency of rs773902 in an Indigenous Australian group comprising 467 individuals from the Tiwi Islands. These people experience high rates of renal disease that may be related to platelet and PAR4 function and are potential recipients of PAR-antagonist treatments. The rs773902 minor allele frequency (Thr120) in the Tiwi Islanders was 0.32, which is similar to European and Asian groups and substantially lower than Melanesians and some African groups. Logistic regression and allele distortion testing revealed no significant associations between the variant and several markers of renal function, as well as blood glucose and blood pressure. These findings suggest that rs773902 is not an important determinant for renal disease in this Indigenous Australian group. However, the relationships between rs773902 genotype and platelet and drug responsiveness in the Tiwi, and the allele frequency in other Indigenous Australian groups should be evaluated.

New Genetic Loci Associated With Chronic Kidney Disease in an Indigenous Australian Population

The common occurrence of renal disease in Australian Aboriginal populations such as Tiwi Islanders may be determined by environmental and genetic factors. To explore genetic contributions, we performed a genome-wide association study (GWAS) of urinary albumin creatinine ratio (ACR) in a sample of 249 Tiwi individuals with genotype data from a 370K Affymetrix single nucleotide polymorphism (SNP) array. A principal component analysis (PCA) of the 249 individual Tiwi cohort and samples from 11 populations included in phase III of the HapMap Project indicated that Tiwi Islanders are a relatively distinct and unique population with no close genetic relationships to the other ethnic groups. After adjusting for age and sex, the proportion of ACR variance explained by the 370K SNPs was estimated to be 37% (using the software GCTA.31; likelihood ratio = 8.06, p-value = 0.002). The GWAS identified eight SNPs that were nominally significantly associated with ACR (p < 0.0005). A replication study of these SNPs was performed in an independent cohort of 497 individuals on the eight SNPs. Four of these SNPs were significantly associated with ACR in the replication sample (p < 0.05), rs4016189 located near the CRIM1 gene (p = 0.000751), rs443816 located in the gene encoding UGT2B11 (p = 0.022), rs6461901 located near the NFE2L3 gene, and rs1535656 located in the RAB14 gene. The SNP rs4016189 was still significant after adjusting for multiple testing. A structural equation model (SEM) demonstrated that the rs4016189 SNP was not associated with other phenotypes such as estimated glomerular filtration rate (eGFR), diabetes, and blood pressure.

Interactive responses of primary producers and grazers to pollution on temperate rocky reefs

Macroalgal beds provide important habitat structure and support primary production for rocky reef communities, but are increasingly degraded as a result of human pressures. Various sources of pollution can have both direct and interactive effects on stressed ecosystems. In particular, interactions involving invertebrate grazers could potentially weaken or strengthen the overall impact of pollution on macroalgal beds. Using a paired impact-control experimental design, we tested the effects of multiple pollution sources (fish farms, marinas, sewerage, and stormwater) on translocated and locally established algal assemblages, while also considering the influence of invertebrate grazers. Marinas directly affected algal assemblages and also reduced densities of amphipods and other invertebrate mesograzers. Fish farms and sewerage outfalls tended to directly increase local establishment of foliose and leathery algae without any indication of changes in herbivory. Overall, pollution impacts on algae did not appear to be strongly mediated by changes in grazer abundance. Instead, mesograzer abundance was closely linked to availability of more complex algal forms, with populations likely to decline concurrently with loss of complex algal habitats. Macrograzers, such as sea urchins, showed no signs of a negative impact from any pollution source; hence, the influence of this group on algal dynamics is probably persistent and independent of moderate pollution levels, potentially adding to the direct impacts of pollution on algal beds in urbanised environments.

BMI Trajectories Associated With Resolution of Elevated Youth BMI and Incident Adult Obesity

BACKGROUND AND OBJECTIVES

Youth with high BMI who become nonobese adults have the same cardiovascular risk factor burden as those who were never obese. However, the early-life BMI trajectories for overweight or obese youth who avoid becoming obese adults have not been described. We aimed to determine and compare the young-childhood BMI trajectories of participants according to their BMI status in youth and adulthood.

METHODS

Bayesian hierarchical piecewise regression modeling was used to analyze the BMI trajectories of 2717 young adults who had up to 8 measures of BMI from childhood (ages 3-18 years) to adulthood (ages 34-49 years).

RESULTS

Compared with those with persistently high BMI, those who resolved their high youth BMI by adulthood had lower average BMI at age 6 years and slower rates of BMI change from young childhood. In addition, their BMI levels started to plateau at 16 years old for females and 21 years old for males, whereas the BMI of those whose high BMI persisted did not stabilize until 25 years old for male subjects and 27 years for female subjects. Compared with those youth who were not overweight or obese and who remained nonobese in adulthood, those who developed obesity had a higher BMI rate of change from 6 years old, and their BMI continued to increase linearly until age 30 years.

CONCLUSIONS

Efforts to alter BMI trajectories for adult obesity should ideally commence before age 6 years. The natural resolution of high BMI starts in adolescence for males and early adulthood for females, suggesting a critical window for secondary prevention.

Abundance and local-scale processes contribute to multi-phyla gradients in global marine diversity

Among the most enduring ecological challenges is an integrated theory explaining the latitudinal biodiversity gradient, including discrepancies observed at different spatial scales. Analysis of Reef Life Survey data for 4127 marine species at 2406 coral and rocky sites worldwide confirms that the total ecoregion richness peaks in low latitudes, near +15°N and -15°S. However, although richness at survey sites is maximal near the equator for vertebrates, it peaks at high latitudes for large mobile invertebrates. Site richness for different groups is dependent on abundance, which is in turn correlated with temperature for fishes and nutrients for macroinvertebrates. We suggest that temperature-mediated fish predation and herbivory have constrained mobile macroinvertebrate diversity at the site scale across the tropics. Conversely, at the ecoregion scale, richness responds positively to coral reef area, highlighting potentially huge global biodiversity losses with coral decline. Improved conservation outcomes require management frameworks, informed by hierarchical monitoring, that cover differing site- and regional-scale processes across diverse taxa, including attention to invertebrate species, which appear disproportionately threatened by warming seas.

Bayesian hierarchical piecewise regression models: a tool to detect trajectory divergence between groups in long-term observational studies

Background

Bayesian hierarchical piecewise regression (BHPR) modeling has not been previously formulated to detect and characterise the mechanism of trajectory divergence between groups of participants that have longitudinal responses with distinct developmental phases. These models are useful when participants in a prospective cohort study are grouped according to a distal dichotomous health outcome. Indeed, a refined understanding of how deleterious risk factor profiles develop across the life-course may help inform early-life interventions. Previous techniques to determine between-group differences in risk factors at each age may result in biased estimate of the age at divergence.

Methods

We demonstrate the use of Bayesian hierarchical piecewise regression (BHPR) to generate a point estimate and credible interval for the age at which trajectories diverge between groups for continuous outcome measures that exhibit non-linear within-person response profiles over time. We illustrate our approach by modeling the divergence in childhood-to-adulthood body mass index (BMI) trajectories between two groups of adults with/without type 2 diabetes mellitus (T2DM) in the Cardiovascular Risk in Young Finns Study (YFS).

Results

Using the proposed BHPR approach, we estimated the BMI profiles of participants with T2DM diverged from healthy participants at age 16 years for males (95% credible interval (CI):13.5–18 years) and 21 years for females (95% CI: 19.5–23 years). These data suggest that a critical window for weight management intervention in preventing T2DM might exist before the age when BMI growth rate is naturally expected to decrease. Simulation showed that when using pairwise comparison of least-square means from categorical mixed models, smaller sample sizes tended to conclude a later age of divergence. In contrast, the point estimate of the divergence time is not biased by sample size when using the proposed BHPR method.

Conclusions

BHPR is a powerful analytic tool to model long-term non-linear longitudinal outcomes, enabling the identification of the age at which risk factor trajectories diverge between groups of participants. The method is suitable for the analysis of unbalanced longitudinal data, with only a limited number of repeated measures per participants and where the time-related outcome is typically marked by transitional changes or by distinct phases of change over time.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0358-9) contains supplementary material, which is available to authorized users.

Consistent multi-level trophic effects of marine reserve protection across northern New Zealand

Through systematic Reef Life Survey censuses of rocky reef fishes, invertebrates and macroalgae at eight marine reserves across northern New Zealand and the Kermadec Islands, we investigated whether a system of no-take marine reserves generates consistent biodiversity outcomes. Ecological responses of reef assemblages to protection from fishing, including potential trophic cascades, were assessed using a control-impact design for the six marine reserves studied with associated reference sites, and also by comparing observations at reserve sites with predictions from random forest models that assume reserve locations are fished. Reserve sites were characterised by higher abundance and biomass of large fishes than fished sites, most notably for snapper Chrysophrys auratus, with forty-fold higher observed biomass inside relative to out. In agreement with conceptual models, significant reserve effects not only reflected direct interactions between fishing and targeted species (higher large fish biomass; higher snapper and lobster abundance), but also second order interactions (lower urchin abundance), third order interactions (higher kelp cover), and fourth order interactions (lower understory algal cover). Unexpectedly, we also found: (i) a consistent trend for higher (~20%) Ecklonia cover across reserves relative to nearby fished sites regardless of lobster and urchin density, (ii) an inconsistent response of crustose coralline algae to urchin density, (iii) low cover of other understory algae in marine reserves with few urchins, and (iv) more variable fish and benthic invertebrate communities at reserve relative to fished locations. Overall, reef food webs showed complex but consistent responses to protection from fishing in well-enforced temperate New Zealand marine reserves. The small proportion of the northeastern New Zealand coastal zone located within marine reserves (~0.2%) encompassed a disproportionately large representation of the full range of fish and benthic invertebrate biodiversity within this region.

A cross-continental comparison of plant and beetle responses to retention of forest patches during timber harvest

Timber harvest can adversely affect forest biota. Recent research and application suggest that retention of mature forest elements (retention forestry), including unharvested patches (or aggregates) within larger harvested units, can benefit biodiversity compared to clearcutting. However, it is unclear whether these benefits can be generalized among the diverse taxa and biomes in which retention forestry is practiced. Lack of comparability in methods for sampling and analyzing responses to timber harvest and edge creation presents a challenge to synthesis. We used a consistent methodology (similarly spaced plots or traps along transects) to investigate responses of vascular plants and ground-active beetles to aggregated retention at replicate sites in each of four temperate and boreal forest types on three continents: Douglas-fir forests in Washington, USA; aspen forests in Minnesota, USA; spruce forests in Sweden; and wet eucalypt forests in Tasmania, Australia. We assessed (1) differences in local (plot-scale) species richness and composition between mature (intact) and regenerating (previously harvested) forest; (2) the lifeboating function of aggregates (capacity to retain species of unharvested forest); and whether intact forests and aggregates (3) are susceptible to edge effects and (4) influence the adjacent regenerating forest. Intact and harvested forests differed in composition but not richness of plants and beetles. The magnitude of this difference was generally similar among regions, but there was considerable heterogeneity of composition within and among replicate sites. Aggregates within harvest units were effective at lifeboating for both plant and beetle communities. Edge effects were uncommon even within the aggregates. In contrast, effects of forest influence on adjacent harvested areas were common and as strong for aggregates as for larger blocks of intact forest. Our results provide strong support for the widespread application of aggregated retention in boreal and temperate forests. The consistency of pattern in four very different regions of the world suggests that, for forest plants and beetles, responses to aggregated retention are likely to apply more widely. Our results suggest that through strategic placement of aggregates, it is possible to maintain the natural heterogeneity and biodiversity of mature forests managed for multiple objectives.

The Combined Effect of Common Genetic Risk Variants on Circulating Lipoproteins Is Evident in Childhood: A Longitudinal Analysis of the Cardiovascular Risk in Young Finns Study

Low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) are modifiable risk factors for cardiovascular disease. Several genetic loci for predisposition to abnormal LDL-C, HDL-C and TG have been identified. However, it remains unclear whether these loci are consistently associated with serum lipid levels at each age or with unique developmental trajectories. Therefore, we assessed the association between genome wide association studies (GWAS) derived polygenic genetic risk scores and LDL-C, HDL-C, and triglyceride trajectories from childhood to adulthood using data available from the 27-year European ‘Cardiovascular Risk in Young Finns’ Study. For 2,442 participants, three weighted genetic risk scores (wGRSs) for HDL-C (38 SNPs), LDL-C (14 SNPs) and triglycerides (24 SNPs) were computed and tested for association with serum lipoprotein levels measured up to 8 times between 1980 and 2011. The categorical analyses revealed no clear divergence of blood lipid trajectories over time between wGRSs categories, with participants in the lower wGRS quartiles tending to have average lipoprotein concentrations 30 to 45% lower than those in the upper-quartile wGRS beginning at age 3 years and continuing through to age 49 years (where the upper-quartile wGRS have 4–7 more risk alleles than the lower wGRS group). Continuous analyses, however, revealed a significant but moderate time-dependent genetic interaction for HDL-C levels, with the association between HDL-C and the continuous HDL-C risk score weakening slightly with age. Conversely, in males, the association between the continuous TG genetic risk score and triglycerides levels tended to be lower in childhood and become more pronounced after the age of 25 years. Although the influence of genetic factors on age-specific lipoprotein values and developmental trajectories is complex, our data show that wGRSs are highly predictive of HDL-C, LDL-C, and triglyceride levels at all ages.

Loss of native rocky reef biodiversity in Australian metropolitan embayments

Urbanisation of the coastal zone represents a key threat to marine biodiversity, including rocky reef communities which often possess disproportionate ecological, recreational and commercial importance. The nature and magnitude of local urban impacts on reef biodiversity near three Australian capital cities were quantified using visual census methods. The most impacted reefs in urbanised embayments were consistently characterised by smaller, faster growing species, reduced fish biomass and richness, and reduced mobile invertebrate abundance and richness. Reef faunal distribution varied significantly with heavy metals, local population density, and proximity to city ports, while native fish and invertebrate communities were most depauperate in locations where invasive species were abundant. Our study adds impetus for improved urban planning and pollution management practises, while also highlighting the potential for skilled volunteers to improve the tracking of changes in marine biodiversity values and the effectiveness of management intervention.

Regulation of the ITGA2 gene by epigenetic mechanisms in prostate cancer

BACKGROUND

Integrin alpha2 beta1 (α2 β1 ) plays an integral role in tumour cell invasion, metastasis and angiogenesis, and altered expression of the receptor has been linked to tumour prognosis in several solid tumours. However, the relationship is complex, with both increased and decreased expression associated with different stages of tumour metastases in several tumour types. The ITGA2 gene, which codes for the α2 subunit, was examined to investigate whether a large CpG island associated with its promoter region is involved in the differential expression of ITGA2 observed in prostate cancer.

METHODS

Bisulphite sequencing of the ITGA2 promoter was used to assess methylation in formalin-fixed paraffin-embedded (FFPE) prostate tumour specimens and prostate cancer cell lines, PC3, 22Rv1 and LNCaP. Changes in ITGA2 mRNA expression were measured using quantitative PCR. ITGA2 functionality was interrogated using cell migration scratch assays and siRNA knockdown experiments.

RESULTS

Bisulphite sequencing revealed strikingly decreased methylation at key CpG sites within the promoter of tumour samples, when compared with normal prostate tissue. Altered methylation of this CpG island is also associated with differences in expression in the non-invasive LNCaP, and the highly metastatic PC3 and 22Rv1 prostate cancer cell lines. Further bisulphite sequencing confirmed that selected CpGs were highly methylated in LNCaP cells, whilst only low levels of methylation were observed in PC3 and 22Rv1 cells, correlating with ITGA2 transcript levels. Examination of the increased expression of ITGA2 was shown to influence migratory potential via scratch assay in PC3, 22Rv1 and LNCaP cells, and was confirmed by siRNA knockdown experiments.

CONCLUSIONS

Taken together, our data supports the assertion that epigenetic modification of the ITGA2 promoter is a mechanism by which ITGA2 expression is regulated.

Identifying the interacting roles of stressors in driving the global loss of canopy-forming to mat-forming algae in marine ecosystems

Identifying the type and strength of interactions between local anthropogenic and other stressors can help to set achievable management targets for degraded marine ecosystems and support their resilience by identifying local actions. We undertook a meta-analysis, using data from 118 studies to test the hypothesis that ongoing global declines in the dominant habitat along temperate rocky coastlines, forests of canopy-forming algae and/or their replacement by mat-forming algae are driven by the nonadditive interactions between local anthropogenic stressors that can be addressed through management actions (fishing, heavy metal pollution, nutrient enrichment and high sediment loads) and other stressors (presence of competitors or grazers, removal of canopy algae, limiting or excessive light, low or high salinity, increasing temperature, high wave exposure and high UV or CO2 ), not as easily amenable to management actions. In general, the cumulative effects of local anthropogenic and other stressors had negative effects on the growth and survival of canopy-forming algae. Conversely, the growth or survival of mat-forming algae was either unaffected or significantly enhanced by the same pairs of stressors. Contrary to our predictions, the majority of interactions between stressors were additive. There were however synergistic interactions between nutrient enrichment and heavy metals, the presence of competitors, low light and increasing temperature, leading to amplified negative effects on canopy-forming algae. There were also synergistic interactions between nutrient enrichment and increasing CO2 and temperature leading to amplified positive effects on mat-forming algae. Our review of the current literature shows that management of nutrient levels, rather than fishing, heavy metal pollution or high sediment loads, would provide the greatest opportunity for preventing the shift from canopy to mat-forming algae, particularly in enclosed bays or estuaries because of the higher prevalence of synergistic interactions between nutrient enrichment with other local and global stressors, and as such it should be prioritized.

Congruence in demersal fish, macroinvertebrate, and macroalgal community turnover on shallow temperate reefs

To support coastal planning through improved understanding of patterns of biotic and abiotic surrogacy at broad scales, we used gradient forest modeling (GFM) to analyze and predict spatial patterns of compositional turnover of demersal fishes, macroinvertebrates, and macroalgae on shallow, temperate Australian reefs. Predictive models were first developed using environmental surrogates with estimates of prediction uncertainty, and then the efficacy of the three assemblages as biosurrogates for each other was assessed. Data from underwater visual surveys of subtidal rocky reefs were collected from the southeastern coastline of continental Australia (including South Australia and Victoria) and the northern coastline of Tasmania. These data were combined with 0.01 degree-resolution gridded environmental variables to develop statistical models of compositional turnover (beta diversity) using GFM. GFM extends the machine learning, ensemble tree-based method of random forests (RF), to allow the simultaneous modeling of multiple taxa. The models were used to generate predictions of compositional turnover for each of the three assemblages within unsurveyed areas across the 6600 km of coastline in the region of interest. The most important predictor for all three assemblages was variability in sea surface temperature (measured as standard deviation from measures taken interannually). Spatial predictions of compositional turnover within unsurveyed areas across the region of interest were remarkably congruent across the three taxa. However, the greatest uncertainty in these predictions varied in location among the different assemblages. Pairwise congruency comparisons of observed and predicted turnover among the three assemblages showed that invertebrate and macroalgal biodiversity were most similar, followed by fishes and macroalgae, and lastly fishes and invertebrate biodiversity, suggesting that of the three assemblages, macroalgae would make the best biosurrogate for both invertebrate and fish compositional turnover.

Effects of a range-expanding sea urchin on behaviour of commercially fished abalone

BACKGROUND

Global climate change has resulted in a southerly range expansion of the habitat modifying sea urchin Centrostephanus rodgersii to the east coast of Tasmania, Australia. Various studies have suggested that this urchin outcompetes black-lipped abalone (Haliotis rubra) for resources, but experiments elucidating the mechanisms are lacking.

METHODOLOGY/PRINCIPAL FINDINGS

We outline a new framework involving experimental manipulations and Markov chain and Pareto modelling to examine the effects of interspecific competition between urchins and abalone and the effect of intraspecific competition in abalone, assessed as effects on behaviour. Manipulations of abalone densities had no detectable effect on urchin behavioural transitions, movement patterns or resightability through time. In contrast, additions of urchins resulted in abalone shifting microhabitats from exposed to sheltered positions, an increase in the proportion of mobile abalone, and declines in abalone resightability through time relative to controls without the urchins. Our results support the hypothesis of asymmetrical competitive interactions between urchins and abalone.

CONCLUSIONS/SIGNIFICANCE

The introduction of urchins to intact algal beds causes abalone to flee and seek shelter in cryptic microhabitat which will negatively impact both their accessibility to such microhabitats, and productivity of the abalone fishery, and will potentially affect their growth and survival, while the presence of the abalone has no detectable effect on the urchin. Our approach involving field-based experiments and modelling could be used to test the effects of other invasive species on native species behaviour.

The Prevalence of Chronic Kidney Disease in Rheumatology Outpatients

Background

The introduction of routine reporting of estimated glomerular filtration rate coupled with a new definition of chronic kidney disease (CKD) has led to an unprecedented focus on kidney disease in many patient groups. In light of this, we performed an audit of patients attending the rheumatology clinics to assess the prevalence of CKD in this population.

Methods

Over a four week period, we reviewed the renal function of all patients attending the rheumatology clinics and day ward at our hospital (n=351). Renal function was assessed using the 4-variable MDRD formula. We then interviewed those patients with estimated glomerular filtration rate (eGFR) of 59 ml/min or lower.

Results

We found a prevalence rate of 18% for stage 3 CKD or lower in our audit population. Surprisingly, 60.3% of patients in this category were not aware of any problems with their kidneys (n=38).

Conclusions

The prevalence rate of 18% for stage 3 CKD or lower is significantly higher than the five per cent reported within the general population. As a result of this audit, we now plan to ensure that these patients undergo measurement of blood pressure, eGFR, and urinalysis on a six to twelve monthly basis.

Past environmental sun exposure and risk of multiple sclerosis: a role for the Cdx-2 Vitamin D receptor variant in this interaction

Multiple studies have provided evidence for an association between reduced sun exposure and increased risk of multiple sclerosis (MS), an association likely to be mediated, at least in part, by the vitamin D hormonal pathway. Herein, we examine whether the vitamin D receptor ( VDR), an integral component of this pathway, influences MS risk in a population-based sample where winter sun exposure in early childhood has been found to be an important determinant of MS risk. Three polymorphisms within the VDR gene were genotyped in 136 MS cases and 235 controls, and associations with MS and past sun exposure were examined by logistic regression. No significant univariate associations between the polymorphisms, rs11574010 ( Cdx-2A > G), rs10735810 ( Fok1T >  C), or rs731236 ( Taq1C > T) and MS risk were observed. However, a significant interaction was observed between winter sun exposure during childhood, genotype at rs11574010, and MS risk ( P = 0.012), with the ‘G’ allele conferring an increased risk of MS in the low sun exposure group (≤2 h/day). No significant interactions were observed for either rs10735810 or rs731236, after stratification by sun exposure. These data provide support for the involvement of the VDR gene in determining MS risk, an interaction likely to be dependent on past sun exposure.

Melanocortin 1 receptor genotype, past environmental sun exposure, and risk of multiple sclerosis

OBJECTIVE

Low past sun exposure, fair skin type, and polymorphisms of the MC1R gene have been associated with multiple sclerosis (MS) risk. We aimed to investigate the interplay between melanocortin 1 receptor gene variants, red hair/fair skin phenotype, and past environmental sun exposure in MS.

METHODS

Population-based case-control study in Tasmania, Australia, involving 136 cases with MS and 272 controls randomly drawn from the community and matched on sex and year of birth. Measures included past sun exposure by calendar and questionnaire, spectrophotometric skin type, and MC1R genotype, with any MC1R Arg151Cys, Arg160Trp, or Asp294His alleles present denoted as red hair color (RHC) variant.

RESULTS

The association between RHC variant genotype and MS was more evident for women (odds ratio 2.02 [1.15-3.54]) than for men (odds ratio 0.65 [0.27-1.57]) (difference in effect, p = 0.03). The RHC variant genotype was associated with behavioral sun avoidance. In addition, increasing summer sun exposure at ages 6 through 10 years was associated with reduced MS risk among those with no RHC variant (p = 0.03), but not among those with RHC variant genotype (p = 0.15; difference in effect, p = 0.02). Similar findings were evident for other past sun exposure measures and when the sample was restricted to women only.

CONCLUSION

The interplay between red hair color variant genotype, red hair/fair skin phenotype, and multiple sclerosis (MS) is complex. The modification of past sun exposure by MC1R genotype provides further support that ultraviolet radiation or derivatives such as vitamin D may be causally related to a reduced MS risk.

Overweight and obesity from childhood to adulthood: a follow-up of participants in the 1985 Australian Schools Health and Fitness Survey

OBJECTIVE

To examine overweight and obesity in Australian children followed through to adulthood.

DESIGN AND PARTICIPANTS

A cohort study of 8498 children aged 7-15 years who participated in the 1985 Australian Schools Health and Fitness Survey; of these, 2208 men and 2363 women completed a follow-up questionnaire at age 24-34 years in 2001-2005.

MAIN OUTCOME MEASURES

Height and weight were measured in 1985, and self-reported at follow-up. The accuracy of self-reported data was checked in 1185 participants. Overweight and obesity in childhood were defined according to international standard definitions for body mass index (BMI), and, in adulthood, as a BMI of 25-29.9 and > or =30 kg/m2, respectively, after correcting for self-report error.

RESULTS

In those with baseline and follow-up data, the prevalence of overweight and obesity in childhood was 8.3% and 1.5% in boys and 9.7% and 1.4% in girls, respectively. At follow-up, the prevalence was 40.1% and 13.0% in men and 19.7% and 11.7% in women. The relative risk (RR) of becoming an obese adult was significantly greater for those who had been obese as children compared with those who had been a healthy weight (RR = 4.7; 95% CI, 3.0-7.2 for boys and RR = 9.2; 95% CI, 6.9-12.3 for girls). The proportion of adult obesity attributable to childhood obesity was 6.4% in males and 12.6% in females.

CONCLUSION

Obesity in childhood was strongly predictive of obesity in early adulthood, but most obese young adults were a healthy weight as children.

Adolescent exposure to high-dose estrogen and subsequent effects on lactation

Treatment with high-dose estrogens has been used to reduce the adult height of tall girls for many years. Short-term side effects on the breast have been reported but there have been no studies to investigate whether there are long-term effects on lactation. This retrospective cohort study of 371 treated and 409 untreated women asked about breastfeeding history. After adjusting for maternal age at first live-birth, treated women (4.4%) were no more likely than untreated women (4.1%) to not commence breastfeeding (RR 1.13, 95% CI 0.50-2.52). After adjusting for age, there was no significant difference in the average duration of breastfeeding between treated (median 41.1 weeks) and untreated women (median 43.3 weeks) (p=0.77) for all live-births. Treated women were not significantly more likely to report physiological reasons for stopping breastfeeding than untreated women. Women treated with high-dose estrogens during adolescence appeared to be no different to untreated women in their ability to lactate.

Leishmaniasis host response loci (lmr1-3) modify disease severity through a Th1/Th2-independent pathway

The severity of disease caused by infection with Leishmania major depends critically on the genetics of the host. Early induction of T helper (Th)1-type immune responses in the resistant C57BL/6 mice and Th2-type responses in the susceptible BALB/c mice are thought to determine cure or disease, respectively. We have previously mapped three host response loci in a genetic cross between C57BL/6 and BALB/c mice, and here we show definitively the involvement of these loci in disease severity using animals congenic for each of the loci. Surprisingly, in the late stage of infection when the difference in disease severity between congenic and parental mice was most pronounced, their cytokine profile correlated with the genetic background of the mice and not with the severity of disease. This indicates that the loci that we have mapped are acting by a mechanism independent of Th phenotype.

A unique sialidase that cleaves the Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc linkage: comparison of its specificity with that of three microbial sialidases toward four sialic acid dimers

We found that the hepatopancreas of oyster, Crassostrea virginica, contained a sialidase capable of releasing Neu5Gc from the novel polysialic acid chain (-->5-O(glycolyl)Neu5Gcalpha2-->)n more efficiently than from the conventional type of polysialic acid chains, (-->8Neu5Acalpha2-->)n, or (-->8Neu5Gcalpha2-->)n. We have partially purified this novel sialidase and compared its reactivity with that of microbial sialidases using four different sialic acid dimers, Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc (Gg2), Neu5Acalpha2-->8Neu5Ac (A2), Neu5Gcalpha2-->8Neu5Gc (G2), and KDNalpha2-->8KDN (K2) as substrates. Hydrolysis was monitored by high performance anion-exchange chromatography with a CarboPac PA-100 column and pulsed amperometric detection, the method by which we can accurately quantitate both the substrate (sialiac acid dimers) and the product (sialic acid monomers). The oyster sialidase effectively hydrolyzed Gg2 and K2, whereas A2 and G2 were poor substrates. Neu5Ac2en but not KDN2en effectively inhibited the hydrolysis of Gg2 by the oyster sialidase. Likewise, the hydrolysis of K2 by the oyster sialidase was inhibited by a cognate inhibitor, KDN2en, but not by Neu5Ac2en. Using the new analytical method we found that Gg2 was hydrolyzed less efficiently than A2 but much more readily than G2 by Arthrobacter ureafaciens sialidase. This result was at variance with the previous report using the thiobarbituric acid method to detect the released free sialic acid [Kitazume, S., et al. (1994) Biochem. Biophys. Res. Commun. 205, 893-898]. In agreement with previous results, Gg2 was a poor substrate for Clostridium perfringens sialidase, while K2 was refractory to all microbial sialidases tested. Thus, the oyster sialidase is novel and distinct from microbial sialidases with regards to glycon- and linkage-specificity. This finding adds an example of the presence of diverse sialidases, in line with the diverse sialic acids and sialic acid linkages that exist in nature. The new sialidase should become useful for both structural and functional studies of sialoglycoconjugates.

Functional analysis and treatment of self-injury associated with transitions

We applied functional analysis methodology to the assessment and treatment of 2 individuals' self-injurious behavior (SIB), which was reported to be occasioned by transitions from one activity or location to another. A structural (task) analysis of activity transitions identified at least three separate components that might influence behavior either alone or in combination: (a) termination of a prechange activity, (b) initiation of a postchange activity, and (c) movement from one location to another. Results of preference and avoidance assessments were used to identify activities to which participants were exposed in varying arrangements during transitions in a functional analysis. Results of 1 participant's functional analysis indicated that his SIB was maintained by avoidance of having to change locations, regardless of the activity terminated prior to the change or the activity initiated following it. The 2nd participant's analysis revealed the same function but also an additional one: avoidance of certain task initiations. This information was used to identify transition contexts during intervention and to design treatment procedures appropriate for a given context and behavioral function. A procedure involving advance notice of an upcoming transition had no effect on SIB, and differential reinforcement of alternative behavior (DRA) had limited effects in the absence of extinction. Sustained decreases in SIB were observed when DRA was combined with extinction and response blocking. Further extensions of functional analysis methodology to the assessment of problem behavior in situations characterized by multiple or protracted stimulus changes are discussed.

Functional analysis and treatment of problem behavior evoked by noise

We conducted a four-part investigation to develop methods for assessing and treating problem behavior evoked by noise. In Phase 1, 7 participants with developmental disabilities who were described as being hypersensitive to specific noises were exposed to a series of noises under controlled conditions. Results for 2 of the participants verified that noise was apparently an aversive event. In Phase 2, results of functional analyses indicated that these 2 participants' problem behaviors were maintained by escape from noise. In Phase 3, preference assessments were conducted to identify reinforcers that might be used during treatment. Finally, in Phase 4, the 2 participants' problem behaviors were successfully treated with extinction, stimulus fading, and a differential-reinforcement-of-other-behavior (DRO) contingency (only 1 participant required DRO). Treatment effects for both participants generalized to their home environments and were maintained during a follow-up assessment. Procedures and results were discussed in terms of their relevance to the systematic assessment of noise as an establishing operation (EO) and, more generally, to the identification of idiosyncratic EO influences on behavior.

Rapid access to uronic acid-based mimetics of Kdn2en from D-glucurono-6,3-lactone

A concise route to novel mimetics of Kdn2en, based on delta4-uronic acids, from D-glucurono-6,3-lactone is presented. Uronic acid-based mimetics in which an aliphatic ether (O-glycoside), a thioether (S-glycoside), or acetamide takes the place of the natural C-6 glycerol sidechain of the sialic acid were synthesized from the key intermediate, methyl 2,3,4-tri-O-acetyl-alpha-D-glucopyranosyluronate bromide.

Synthesis of delta4-beta-D-glucopyranosiduronic acids as mimetics of 2,3-unsaturated sialic acids for sialidase inhibition

Mimetics of Neu5Ac2en and KDN2en, based on delta4-beta-delta-glucopyranosiduronic acids, have been synthesised. The Neu5Ac2en mimetic 5 showed inhibition of both bacterial and viral sialidases, with inhibition of the viral sialidase being comparable to that of Neu5Ac2en itself.

Catalysis by a new sialidase, deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm), initially forms a less stable alpha-anomer of 3-deoxy-D-glycero-D-galacto-nonulosonic acid and is strongly inhibited by the transition state analogue, 2-deoxy-2, 3-didehydro-D-glycero-D-galacto-2-nonulopyranosonic acid, but not by 2-deoxy-2,3-didehydro-N-acetylneuraminic acid

Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and 1H NMR spectroscopy. Vmax/Km values determined for synthetic and natural substrates of KDNase Sm reveal that 4-methylumbelliferyl-KDN (KDNalpha2MeUmb, Vmax/Km = 0.033 min-1) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2, 3-didehydro-2,3-dideoxy-D-galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of KDNase Sm (Ki = 7.7 microM versus Km = 42 microM for KDNalpha2MeUmb). 2-Deoxy-2, 3-didehydro-N-acetylneuraminic acid and 2-deoxy-2, 3-didehydro-N-glycolylneuraminic acid are known to be strong competitive inhibitors for bacterial sialidases such as Arthrobacter ureafaciens sialidase; however, KDNase Sm activity is not significantly inhibited by these compounds. This observation suggests that the hydroxyl group at C-5 is important for recognition of the inhibitor by the enzyme. Reversible addition of water molecule (or hydroxide ion) to the reactive sialosyl cation, presumably formed at the catalytic site of KDNase Sm, eventually gives rise to two different adducts, the alpha- and beta-anomers of free 3-deoxy-D-glycero-D-galacto-nonulosonic acid. 1H NMR spectroscopic studies clearly demonstrate that the thermodynamically less stable alpha-form is preferentially formed as the first product of the cleavage reaction and that isomerization rapidly follows, leading to an equilibrium mixture of the two isomers, the beta-isomer being the major species at equilibrium. Therefore, we propose that KDNase Sm catalysis proceeds via a mechanism common to the known exosialidases, but the recognition of the substituent at C-5 by the enzyme differs.

Airway muscle stereology: implications for increased shortening in asthma

Increased airway smooth muscle, resulting from either hyperplasia or hypertrophy, has been implicated as a cause of excessive bronchoconstriction in asthma despite the many methodologic limitations of studies to date. Our recent failure to demonstrate increased muscle volume in an asthmatic airway preparation having 3-fold greater shortening than nonasthmatic controls prompted us to reassess the quantity of muscle in asthmatic versus nonasthmatic airways. Smooth muscle was quantified in axially sectioned, 2nd- to 4th-generation bronchi, using standardized stereologic methods on high-magnification images of cross-sectional airway smooth muscle profiles in tissues from five asthmatic subjects and five nonasthmatic smokers. When data were normalized by total cross-sectional tissue area, no differences between the two groups (asthmatic versus nonasthmatic) were detected for the proportion of smooth muscle (3.45 +/- 0.81% versus 2.74 +/- 0.76%), extracellular matrix between muscle cells (1.65 +/- 0.46% versus 1.06 +/- 0.25%), or connective tissue within smooth muscle bundles (1.65 +/- 0.34% versus 1.53 +/- 0.59%). These methodologies for evaluating cross-sectional airway muscle in axial airway sections at high resolution provide no evidence of increased airway smooth muscle in asthmatic large airways, and suggest that differences in mechanical responses of asthmatic airways cannot be explained solely by the amount of smooth muscle.

Hypothesis: excessive bronchoconstriction in asthma is due to decreased airway elastance

Based on the strikingly different mechanical properties of airway smooth muscle preparations of different species, we hypothesized that a decrease in the elastance of nonmuscle elements within airway walls of asthmatics reduces the load limiting smooth muscle shortening, thereby allowing excessive smooth muscle shortening and bronchoconstriction. Full thickness, circumferentially cut, lobar bronchial preparations were obtained from one asthmatic and six nonasthmatic lobectomy subjects. Passive tension of the asthmatic preparation was less than that for any nonasthmatic preparation at all lengths below that for optimal force generation (Lmax). Maximal isometric force generation was greater in the asthmatic specimen (2.32 g) than in the nonasthmatic specimens (0.90 +/- 0.15 g), with stress threefold higher for the asthmatic tissue. Isotonic shortening of the asthmatic preparation was strikingly greater at starting lengths less than or equal to Lmax, with maximal fractional shortening being 31% versus 11 +/- 2% for nonasthmatic preparations. Morphometric analysis revealed no differences in cross-sectional areas of smooth muscle for asthmatic versus nonasthmatic preparations. We conclude that the reduced tissue elastance may account for the greater muscle shortening by placing a lesser load upon the smooth muscle. Airway inflammation in asthma may alter connective tissue matrix elements within airway walls leading to this decreased elastance and excessive smooth muscle shortening.

Role of leukotrienes in airway hyperresponsiveness in guinea-pigs

1. Repeated aerosolization of leukotriene C4 (LTC4) to guinea-pigs produced leftward shift in their pulmonary resistance (RL) dose-response curves to inhaled acetylcholine (ACh) without increasing the maximum responses. 2. Repeated LTC4 aerosolization did not increase airway eosinophils. 3. The 5-lipoxygenase-activating protein (FLAP) inhibitor, MK-886, prevented the leftward shift in RL dose-response curves to ACh following repeated antigen challenge in guinea-pigs. 4. MK-886 did not inhibit the increased maximal RL produced by repeated antigen challenge, nor inhibit the airway eosinophilia induced by repeated antigen challenge. 5. Our findings suggest that leukotrienes may account for the leftward shift in pulmonary resistance responses caused by antigen but do not cause the airway eosinophilia nor enhanced maximum broncho-constrictor response to antigen.

cis-bis(pyridine)platinum(II) organoamides with unexpected growth inhibition properties and antitumor activity

The platinum(II) organoamides [Pt(NRCH2)2L2] (L = pyridine (py), R = p-HC6F4, C6F5,p-IC6F4,p-CIC6F4,p-C6F5C6F4; L = 4-methylpyridine, R = p-HC6F4) and [Pt(NRCH2CH2NR')(py)2] (R = p-HC6F4, R' = C6F5, p-BrC6F4, or p-MeC6F4) inhibit the growth of murine L1210 leukemia cells in culture with ID50 values for continuous exposure in the range 0.6-2.7 microM. Representative complexes are also active against L1210 cells in 2-h pulse exposures, as well as against the cisplatin-resistant variant L1210/DDP and human colonic carcinoma cell lines HT 29 and BE. Three complexes [Pt(NRCH2)2L2] (R = p-HC6F4, C6F5, or p-IC6F4) have good activity (T/C greater than or equal to 180%) against P388 leukemia in mice, and all other compounds tested are active except when R = p-C6F5C6F4, L = py. Although the molecular basis of the biological activity of these complexes is not known, the observation of good activity for amineplatinum(II) compounds with no hydrogen substituents on the nitrogen donor atoms introduces a new factor in the anticancer behavior of platinum(II) complexes.

Nedocromil sodium inhibits airway hyperresponsiveness and eosinophilic infiltration induced by repeated antigen challenge in guinea-pigs

1. Repeated exposure to ovalbumin aerosol produced significant increases in epithelial eosinophils of airways of all sizes and produced increased pulmonary resistance (RL) to inhaled acetylcholine (ACh) in guinea-pigs. 2. Nedocromil sodium 10 mg ml-1, by nebulization prior to each ovalbumin (OA) challenge inhibited both the airway eosinophilia and hyperresponsiveness to ACh. 3. Nedocromil sodium pretreatment (10 mg ml-1 by nebulization) 10 min prior to OA completely inhibited the acute bronchoconstrictor response to OA. 4. Our findings suggest that nedocromil sodium inhibits airway hyperresponsiveness by inhibiting eosinophilic infiltration, or by simultaneously inhibiting mechanisms involved in both processes.

Capsaicin inhibits airway hyperresponsiveness but not lipoxygenase activity or eosinophilia after repeated aerosolized antigen in guinea pigs

To evaluate the role of tachykinins in airway hyperresponsiveness following repeated aerosolized antigen challenge in guinea pigs, we treated 12 guinea pigs with capsaicin (105.6 mg cumulative dose given subcutaneously over 5 days) after sensitization to ovalbumin (OA) and before three repeated OA aerosol challenges per wk for 4 to 5 wk. Ten guinea pigs received identical OA sensitization and challenges without capsaicin treatment, and four of eight nonsensitized controls received capsaicin followed by saline challenges. Capsaicin treatment did not alter antibody responses to OA as assessed by passive cutaneous anaphylaxis, nor did it alter lipoxygenase products from OA-stimulated bronchial tissue in vitro. Capsaicin completely inhibited the increased pulmonary resistance (RL) to acetylcholine produced by repeated aerosolized OA, whereas it did not alter baseline RL or acetylcholine responses of controls. Capsaicin did not alter airway eosinophilia induced by repeated aerosolized OA. We conclude that neuropeptides play an important role in antigen-induced airway hyperresponsiveness without altering antibody levels, lipoxygenase mediator production, or airway eosinophilia.

Inhibition of antigen-induced airway hyperresponsiveness, but not acute hypoxia nor airway eosinophilia, by an antagonist of platelet-activating factor

The role of platelet-activating factor (PAF) in Ag-induced airway hyperresponsiveness was evaluated in a guinea pig model using the PAF antagonist SDZ 64-412. Repeated OVA challenge by aerosol (twice weekly x 4 wk) of previously sensitized guinea pigs produced striking airway hyperresponsiveness as determined by pulmonary resistance changes to increasing doses of inhaled acetylcholine given 3 days after the last OVA challenge. Each OVA challenge produced significant hypoxia that was unaffected by oral pretreatment with 20 mg/kg SDZ 64-412, 2 h before each challenge (pO2 = 35 +/- 2 mm Hg for OVA alone vs 40 +/- 6 mm Hg for SDZ and OVA groups, respectively). SDZ 64-412 pretreatment abolished the airway hyperresponsiveness resulting from repeated Ag challenge. Morphometric analysis revealed that SDZ 64-412 treatment had no effect on the increased numbers of eosinophils that infiltrated the airways of OVA-challenged guinea pigs. These results suggest that PAF may be a primary mediator of airway hyperresponsiveness, but not acute bronchoconstriction, induced by repeated Ag challenge. This activity of PAF appears independent of eosinophil recruitment to airways.

Inhibition of antigen-induced airway hyperresponsiveness, but not acute hypoxia nor airway eosinophilia, by an antagonist of platelet-activating factor

The role of platelet-activating factor (PAF) in Ag-induced airway hyperresponsiveness was evaluated in a guinea pig model using the PAF antagonist SDZ 64-412. Repeated OVA challenge by aerosol (twice weekly x 4 wk) of previously sensitized guinea pigs produced striking airway hyperresponsiveness as determined by pulmonary resistance changes to increasing doses of inhaled acetylcholine given 3 days after the last OVA challenge. Each OVA challenge produced significant hypoxia that was unaffected by oral pretreatment with 20 mg/kg SDZ 64-412, 2 h before each challenge (pO2 = 35 +/- 2 mm Hg for OVA alone vs 40 +/- 6 mm Hg for SDZ and OVA groups, respectively). SDZ 64-412 pretreatment abolished the airway hyperresponsiveness resulting from repeated Ag challenge. Morphometric analysis revealed that SDZ 64-412 treatment had no effect on the increased numbers of eosinophils that infiltrated the airways of OVA-challenged guinea pigs. These results suggest that PAF may be a primary mediator of airway hyperresponsiveness, but not acute bronchoconstriction, induced by repeated Ag challenge. This activity of PAF appears independent of eosinophil recruitment to airways.