Dietary nitrate supplementation increases fractional exhaled nitric oxide: implications for the assessment of airway health in athletes

Background: Fractional exhaled nitric oxide (FeNO) is a simple tool that has an established role in the assessment of airway inflammation in athletes. Specifically, FeNO provides information concerning asthma phenotypes, aetiology of respiratory symptoms, response to anti-inflammatory agents, course of disease and adherence to medication. It is recognised that FeNO can be influenced by a variety of external factors (e.g. atopic status, exercise, respiratory tract infection), however, there remains limited research concerning the impact of dietary nitrate ingestion. The primary aim of this study was therefore to evaluate the effect of acute dietary nitrate supplementation on FeNO and resting pulmonary function parameters. Method: The study was conducted as a randomised double-blind placebo-controlled trial. Thirty male endurance trained athletes (age: 28 ± 6 yrs; BMI: 23 ± 2 kg.m-2) free from cardio-respiratory and metabolic disease, and stable at time of study entry (i.e. entirely asymptomatic without recent respiratory tract infection) attended the laboratory on two separate occasions. On arrival to the laboratory, athletes consumed either 140ml nitrate-rich beetroot juice (15.2 mmol nitrate) (NIT) or nitrate-depleted beetroot juice (0 mmol nitrate) (PLA). In accordance with international guidelines all athletes performed resting FeNO and forced spirometry (2.5hrs post ingestion). Airway inflammation was evaluated using established FeNO thresholds: (intermediate [≥25ppb] and high [>50ppb]). Results: All athletes demonstrated normal baseline lung function (FEV1 % predicted >80%). A three-fold rise in resting FeNO was observed following NIT (median [IQR]): 32ppb [37] in comparison to PLA: 10ppb [12] (P0.05). Conclusion: Dietary nitrate ingestion should be considered when employing FeNO for the assessment of airway health in athletes. Our findings have implications concerning the decision to initiate or modify inhaler therapy. Further research is therefore required to determine the impact of chronic dietary nitrat

Development of corn seedlings after a period of exposition to various water potential

Fungicide treated and untreated corn seeds were sets to germinate under varying water availability conditions (0 to -12atm water potential). The seedlings obtained on each individual treatment were subsequently grown under ideal available water conditions. The results permitted to conclude that the occurrence of a water deficit during the on set of the germination process results in reductions on the length of the embryonic structures, particularly the epicotil. This effect attenuates with times due to the increase in growth velocity in environments where water potential is lower. Fungicid treated seeds, did not appear to be consistently vantageous in environments with water stress.Submetendo sementes de milho com e sem tratamento fungicida, a ambientes de germinação variáveis quanto à disponibilidade de água (0 a -12atm), o presente trabalho avaliou o desenvolvimento posterior das plântulas postas em ambientes sem limitações hídricas. Os resultados obtidos permitiram concluir que a ocorrência de déficit hídrico, durante o início do processo de germinação, promove reduções posteriores no comprimento das estruturas embrionárias e, de forma mais acentuada, do epicótilo; apesar disso, esse efeito se atenua com o passar do tempo pela elevação progressiva na velocidade de crescimento em ambientes que oferecem menores potenciais hídricos. Paralelamente, o tratamento fungicida das sementes pode não trazer vantagens em ambientes hidricamente deficientes; esta afirmação, contudo, considera o papel toalha como meio fornecedor de água o que, em contrapartida, exige cautela na sua extrapolação para as condições proporcionadas pelo solo

Avaliação da embebição e do desenvolvimento inicial das estruturas embrionárias de sementes de milho submetidas a diferentes potenciais hídricos

Substrates with water potentials between O and -12atm, were used to evaluate the behavior of corn seeds during the germination process. Water deficiency treatments were compared with the control (adequate available water) using seeds with and without fungicide treatment. The analysis and the interpretation of the results permitted to conclude that the absorption of water, the emergency and the initial development of the embryonic structures are interdependent and vary with the water deficit. For these cases the reduction of water potential promotes difficulties in the evolution of the processes. The presence of fungicide treatment may not influence quantitatively the processes occurring in the beginning of the germination.Empregando substratos com potenciais hídricos variáveis entre 0 e -12atm, o presente trabalho objetivou avaliar o comportamento das sementes de milho postas a germinar. As situações de deficiência hídrica foram diretamente comparadas à testemunha (plena disponibilidade de água), usando sementes com e sem tratamento fungicida. A análise e a interpretação dos resultados permitiram concluir que a absorção de água, a emergência e o desenvolvimento inicial das estruturas embrionárias são interdependentes e reagem no mesmo sentido ao déficit hídrico; para esses casos, a redução do potencial hídrico promove dificuldades na evolução dos processos. Paralelamente, a presença de tratamento fungicida pode não influenciar, quantitativamente, os fenômenos envolvidos no início da germinação

Modelling of Grass Pollen Interannual Variability in the UK: A Mechanistic Approach

Background Seasonal pollen integral (SPIn) – the integral over time of pollen concentration - is considered an important parameter in aerobiological studies. It is mainly used to quantify the severity of pollen seasons as well as in numerical models to simulate pollen emissions and concentrations. According to the recent studies the SPIn interannual variability is modelled using a statistical approach by analysing 10-20 years of pollen and meteorological observations at the specific region. Methods This study is based on a mechanistic approach which describes grass growth by variation of meteorological parameters in the UK: air temperature, precipitation, shortwave radiation, as well as CO2. Our approach suggests that grass growth correlates with the grass SPIn interannual variability. Six pollen observation sites across the UK have been chosen for this study: Worcester, Leicester, Cardiff, Plymouth, Isle of Wight and Invergowrie. The pollen observation data cover a 21-year period (1995-2015). The meteorological data, provided by the UK Met Office, are gridded data with 5 km horizontal resolution over the UK. The mechanistic approach will be tested for the selected sites and then applied to the grid. Results Analysis of the grass SPIn interannual variability showed the highest SPIn variation at Worcester (from 2908 pollen*day/m3 in 1995 to 10856 pollen*day/m3 in 2006) and Isle of Wight (from 1423 pollen*day/m3 in 1999 to 6815 pollen*day/m3 in 2013) among the considered stations. This could be explained by high variation of local pollen sources at the Worcester site and atmospheric transport from the South to Isle of Wight. Conclusions The grass SPIn analysis did not show correlation between the selected stations during the period studied. The new approach also has the practical application that it can be used directly to estimate local grass pollen productivity in the UK for a better estimation of the severity of the grass pollen season

On the Influence of Pre- and In-seasonal Meteorological Conditions on Grass Pollen Interannual Variations in the UK

Up to 30% of the UK population are sensitized to grass pollen. Therefore, grass pollen is considered the most allergenic pollen type in the UK. Estimating the grass pollen season severity and interannual variation is a key task in aerobiological studies. The season severity is quantified using the Seasonal Pollen Integral (SPIn) - the integral over time of daily pollen concentration. This severity is tightly connected to personal exposure and the symptoms among hay fever sufferers. Recent studies suggest that the SPIn interannual variation is related to variation in pre- and in-seasonal meteorological conditions at the specific region. Here, we investigate whether the SPIn interannual variation can be explained by variation in pre-seasonal precipitation and in-seasonal air temperatures in the UK. Seven UK pollen observation sites have been chosen in the study: Worcester, Plymouth, Isle of Wight, Belfast, York, Islington (London) and Ipswich. The pollen observations cover the 1996-2018 grass pollen seasons, where we include those years without substantial gaps in the daily time series, thereby providing 116 pollen seasons to be included in the study. Maximum daily air temperature and precipitation data have been taken from the global summary of the day meteorological dataset. The SPIn, temperature and precipitation data have been transformed to interannual variations relatively mean value at each pollen observation site. The transformed time series have been analysed by looking for correlation between variations in pre-seasonal precipitation, in-seasonal air temperature and SPIn. The results show positive and significant correlation between pre-seasonal precipitation and SPIn variations (R = 0.35, p-value < 0.001) at the selected sites. Station-wise, the correlation is positive and significant at Worcester (R = 0.54, p-value < 0.01) and Ipswich (R = 0.81, p-value < 0.05). Correlation between in-seasonal air temperature and SPIn variations is also positive and significant (R = 0.33, p-value < 0.001) at the sites. Station-wise, the correlation coefficient is positive and significant at Worcester, Plymouth and Islington (R = 0.51, 0.50, 0.59, respectively p-value < 0.05). The study indicates that the SPIn variation is not a regional scale phenomenon in the UK. Instead, it appears to be related to local environmental effects. It is also shown that the pre- and in-seasonal meteorological conditions are statistically correlated with the SPIn, which may be explained by the fact that governing processes affecting the SPIn are related to both pollen production (pre-season) and atmospheric conditions (in-season)