Summary
Background
Allergen and fungal exposures are important risk factors for asthma. We conducted a longitudinal analysis of allergen levels in Melbourne homes between 1996 and 1998 to examine the ...effects of changing residential characteristics on allergen and fungal levels. We also examined the changes in levels of indoor allergens.
Methods
The subjects were participants in the European Community Respiratory Health Survey (ECRHS) in Melbourne. In 1996, 485 subjects participated in a follow‐up study, which involved both home and laboratory visits. Dust and air samples were collected from participants' bedrooms and a validated residential questionnaire was administered. In 1998, 360 participants underwent further follow‐up. House dust mite (Der p 1) and cat allergens (Fel d 1) and ergosterol were measured in dust.
Results
We observed moderate within home correlations between 1996 and 1998 in floor Der p 1 (intraclass correlation ICC=0.48), bed Der p 1 (ICC=0.61), Fel d 1 (κ=0.53) and ergosterol (ICC=0.28) levels. We found that the floor Der p 1 levels decreased from 1996 to 1998 in the homes of participants who moved to an attached home, moved their bedrooms to the first floor, removed fitted carpet or central heating. Replacing or vacuuming the mattress more than twice per year reduced levels of Der p 1 in the bed. Ergosterol levels were reduced by removing visible mould and fitted carpet.
Conclusions
These findings provide evidence to support current advice with regard to allergen avoidance in patients with dust mite and fungal allergies.
Hereditary hemochromatosis can cause individuals to absorb too much iron from their diet. Higher tissue iron content, below the threshold of toxicity, may enhance oxygen carrying capacity and offer a ...competitive advantage. Single nucleotide polymorphisms (SNP) in the homeostatic iron regulator (HFE) gene have been shown to modify iron metabolism and can be used to predict an individual's risk of hemochromatosis. Several studies have shown that HFE genotypes are associated with elite endurance athlete status; however, no studies have examined whether HFE genotypes are associated with endurance performance.
The objectives of this study were to determine whether there was an association between HFE risk genotypes (rs1800562 and rs1799945) and endurance performance in a 10-km cycling time trial as well as maximal oxygen uptake (V˙O2peak), an indicator of aerobic capacity.
Competitive male athletes (n = 100; age = 25 ± 4 yr) completed a 10-km cycling time trial. DNA was isolated from saliva and genotyped for the rs1800562 (C282Y) and rs1799945 (H63D) SNP in HFE. Athletes were classified as low risk (n = 88) or medium/high risk (n = 11) based on their HFE genotype for both SNP using an algorithm. ANCOVA was conducted to compare outcome variables between both groups.
Individuals with the medium- or high-risk genotype were ~8% (1.3 min) faster than those with the low-risk genotype (17.0 ± 0.8 vs 18.3 ± 0.3 min, P = 0.05). V˙O2peak was ~17% (7.9 mL·kg-1⋅min-1) higher in individuals with the medium- or high-risk genotype compared with those with the low-risk genotype (54.6 ± 3.2 vs 46.7 ± 1.0 mL·kg-1⋅min-1, P = 0.003).
Our findings show that HFE risk genotypes are associated with improved endurance performance and increased V˙O2peak in male athletes.
Objective Patients with severe chronic kidney disease (CKD) and peripheral vascular disease are at increased risk of major adverse limb events (MALEs) and death; however, patients with end-stage ...renal disease have been excluded in current objective performance goals. We evaluated the effect of severe (class 4 and 5) CKD on outcomes after infrainguinal endovascular arterial interventions. Methods All primary peripheral vascular interventions (PVIs) performed at a single institution (January 2002 through December 2009) were included. End points were defined by Society for Vascular Surgery objective performance goals for critical limb ischemia (CLI), which include all-cause mortality, reintervention, and composite end points of death or amputation and MALEs (reintervention or amputation). Univariate and multivariable analysis was used to examine the effect of severe CKD on study end points. Results A total of 879 PVIs were performed, with severe CKD in 125 (14%). Severe CKD patients were significantly ( P < .05) more likely to have diabetes (64% vs 46%), CLI (72% vs 11%), and need a multilevel PVI (34% vs 19%) or tibial intervention (35% vs 20%) compared with the remainder of the cohort. Distribution of TransAtlantic Inter-Society Consensus C and D lesions were similar (19% severe CKD vs 15%; P = .2). Severe CKD predicted perioperative (30-day) reintervention (odds ratio OR, 2.3; 95% confidence interval CI, 1.5-4; P = .05), amputation or death (OR, 3.1; 95% CI, 1.1-9; P = .04), and MALEs (OR, 2.8; 95% CI, 1.3-6.1; P = .04), which was independent of CLI in multivariable regression analysis. On Kaplan-Meier analysis, severe CKD was significantly (log-rank P < .05) associated with death (31% ± 4% vs 7% ± 1%), amputation (14% ± 3% vs 3% ± 1%), and MALEs (40% ± 5% vs 26% ± 2%) at 1 year. Freedom from reintervention was similar at 1 year (70% ± 5% severe CKD vs 75% ± 2%; P = .23). Risk-adjusted (age, CLI, diabetes, coronary artery disease) Cox proportional hazards regression showed that severe CKD increased the risk of late mortality (hazard ratio HR, 2.4; 95% CI, 1.8-3.2; P < .01), amputation (HR, 2.1; 95% CI, 1.1-3.9; P = .02), and death or amputation (HR, 1.8; 95% CI, 1.3-2.4; P = .04), without increasing the risk of late reinterventions or MALEs. Conclusions CKD independently predicts early and late adverse events after a PVI, in particular, excessive mortality. CKD should figure prominently in clinical decision making for patients with peripheral vascular disease.
In the 1960s, the basidiomycete Oncobasium theobromae was identified as the cause of a devastating disease in Papua New Guinea named 'vascular-streak dieback' (VSD). VSD now causes heavy losses of ...seedlings and in plantations throughout Southeast Asia and the Pacific. Symptoms include a green-spotted chlorosis, fall of the second or third youngest leaf, raised lenticels, and blackened vascular traces at leaf scars and browning of affected xylem. Eventually all new leaves fall and, if the fungus spreads to the trunk, trees die. O. theobromae is a highly specialised, nearly obligate parasite of cacao that probably evolved as an endophyte on an as yet unidentified indigenous host. The rate and distance of disease spread on cacao is limited. Sporocarps only develop when leaf fall occurs during wet weather, basidiospores only remain viable for a few hours around dawn, and transmission through seed or infected cuttings has not been demonstrated. Strict quarantine measures are needed to reduce interregional spread. Effective control relies on integrated management, including the planting of less susceptible genotypes, nursery hygiene, canopy pruning and shade management.
Pathogens of the Stramenopile genus Phytophthora cause the greatest disease losses to global cocoa production. P. megakarya causes significant pod rot and losses due to canker in West Africa, while ...P. capsici and P. citrophthora cause pod rots in Central and South America. The only global, and most damaging, species is P. palmivora, which attacks all parts of the cocoa tree at all stages of the growing cycle, causing 20-30% global yield losses through black pod rot, and killing up to 10% of trees annually through stem cankers. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum, resulting in an explosive epidemic during favorable environmental conditions. The spread of localized pathogens must be prevented by effective quarantine barriers. Resistance is typically low in commercial cocoa genotypes. Disease losses can be reduced through integrated management practices that include pruning and shade management, leaf mulching, regular and complete harvesting, sanitation and pod case disposal, appropriate fertilizer application and targeted fungicide use. Packaging these options to improve uptake by smallholders presents a major challenge for the industry.
We have examined the responses of suspension cultured tobacco cells after inoculation with zoospores from compatible or incompatible races of the Oomycete pathogen Phytophthora nicotianae. The ...incompatible interaction, characterized by the production of reactive oxygen species (ROS) (specifically superoxide (<$>{\rm HO^{\,\cdot}_{2}/O_{2}^{\minus}}<$>) and hydrogen peroxide (H2O2)), and by a hypersensitive response (HR), was not dependent upon the presence of exogenous calcium. However, perturbation of calcium ion movements by EGTA or LaCl3suppressed both ROS production and the extent of cell death. The Ca2+-specific ionophore, A23187, slightly enhanced ROS production during the incompatible interaction but had no effect on the responses of susceptible or unchallenged cells. These results confirm that both ROS production and the HR are potentiated by movement of endogenous calcium across the plasmalemma. While there was no evidence of a transmembrane K+/H+exchange immediately following incompatible zoospore challenge, a later potassium efflux from cells coincided with the onset of the HR. Unexpectedly, medium pH drifted downwards during all host cell responses suggesting that alkaline peroxidases are not the major source of ROS generation during an incompatible tobacco cell/zoospore interaction.
The biosynthesis and processing of proinsulin was investigated in the diabetic Goto-Kakizaki (GK) rat. Immunofluorescence microscopy comparing GK and Wistar control rat pancreata revealed marked ...changes in the distribution of alpha-cells and pronounced beta-cell heterogeneity in the expression patterns of insulin, prohormone convertases PC1, PC2, carboxypeptidase E (CPE) and the PC-binding proteins 7B2 and ProSAAS. Western blot analyses of isolated islets revealed little difference in PC1 and CPE expression but PC2 immunoreactivity was markedly lower in the GK islets. The processing of the PC2-dependent substrate chromogranin A was reduced as evidenced by the appearance of intermediates. No differences were seen in the biosynthesis and post-translational modification of PC1, PC2 or CPE following incubation of islets in 16.7 mM glucose, but incubation in 3.3 mM glucose resulted in decreased PC2 biosynthesis in the GK islets. The rates of biosynthesis, processing and secretion of newly synthesized (pro)insulin were comparable. Circulating insulin immunoreactivity in both Wistar and GK rats was predominantly insulin 1 and 2 in the expected ratios with no (pro)insulin evident. Thus, the marked changes in islet morphology and PC2 expression did not impact the rate or extent of proinsulin processing either in vitro or in vivo in this experimental model.
Southern hybridization and polymerase chain reaction data indicate that the 5S ribosomal RNA gene is linked to the ribosomal RNA gene repeat unit in the oomycetes, Phytophthora vignae, P. cinnamomi, ...P. megasperma f.sp. glycinea and Saprolegnia ferax, and is apparently transcribed in the same direction as the large and small subunit ribosomal RNA genes. The polymerase chain reaction has been used to amplify all components of the entire ribosomal RNA gene repeat unit for each of these oomycetes. The total size of all amplified products is identical to the size of the ribosomal RNA gene repeat unit, as determined by Southern analysis.
Phytophthora species have significant cultural, ecological and economic impacts. Potassium phosphonate (phosphite), used to manage Phytophthora diseases, acts through enhanced plant defence ...responses, although the precise mechanism remains elusive. We developed an Arabidopsis thaliana/P. palmivora pathosystem to examine the role of plant defences in phosphite action. A. thaliana seedlings grown with and without phosphite were inoculated with zoospores of P. palmivora. Key stages in pathogen development and host responses were quantified. Hyphal disruption was associated with the release of O super(2-) at the site of attempted penetration in phosphite-treated seedlings. Cell viability in treated seedlings rapidly declined to 22% between 9 and 12 hours after zoospore challenge, indicating hypersensitive cell death. This is the first report of O super(2-) release in pathogen-challenged Arabidopsis. As in other incompatible interactions, the timing of O super(2-) release immediately precedes hypersensitive cell death. Phosphite treatment also resulted in more intense accumulation of phenolics and camalexin. Application of phosphite to A. thaliana induces a similar host defence response to that reported in incompatible host-pathogen interactions.
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