Do body condition and plumage during fuelling predict northwards departure dates of Great Knots Calidris tenuirostris from north-west Australia?

It is often assumed that strong selection pressures give rise to trade-offs between body condition and time in long-distance migrating birds. Birds that are 'behind schedule' in fuel deposition or moult should delay departure, and this should result in a negative correlation between initial condition and departure date. We tested this hypothesis in the Great Knot Calidris tenuirostris migrating from north-west Australia to eastern Asia en route to Siberia. Great Knot gain mass and moult into breeding plumage before leaving northern Australia in late March and early April, and fly 5400-6000 km to eastern China and Korea. We radiotracked 27 individuals (17 males and ten females) to determine departure dates; 23 migrated and four remained in Australia. We characterized body condition at capture using body mass, predicted pectoral muscle mass (based on ultrasound estimates of the size of the pectoral muscles) and breeding plumage scores. Residual condition indices were uncorrelated, indicating that at the individual level, variation in one fuelling component was not strongly associated with variation in the other components. Birds that did not depart had lower residual body mass and breeding plumage indices than those that did migrate; these four birds may have been subadults. Neither sex, size nor the condition indices explained variation in departure date of migrants. Reasons for this are explored. Departure dates for northward migrating waders indicate that the migration window (span over which birds depart) decreases with proximity to the northern breeding grounds. We suggest that migration schedules become tighter as birds get nearer to the breeding grounds. Thus the lack of a relationship between condition and departure date in Great Knots may reflect the fact that the departure episode under study is the first one in sequence and is still 4-8 weeks before breeding

Ambient temperature does not affect fuelling rate in absence of digestive constraints in long-distance migrant shorebird fuelling up in captivity

Pre-flight fuelling rates in free-living red knots Calidris canutus, a specialized long-distance migrating shorebird species, are positively correlated with latitude and negatively with temperature. The single published hypothesis to explain these relationships is the heat load hypothesis that states that in warm climates red knots may overheat during fuelling. To limit endogenous heat production (measurable as basal metabolic rate BMR), birds would minimize the growth of digestive organs at a time they need. This hypothesis makes the implicit assumption that BMR is mainly driven by digestive organ size variation during pre-flight fuelling. To test the validity of this assumption, we fed captive knots with trout pellet food, a diet previously shown to quickly lead to atrophied digestive organs, during a fuelling episode. Birds were exposed to two thermal treatments (6 and 24°C) previously shown to generate different fuelling rates in knots. We made two predictions. First, easily digested trout pellet food rather than hard-shelled prey removes the heat contribution of the gut and would therefore eliminate an ambient temperature effect on fuelling rate. Second, if digestive organs were the main contributors to variations in BMR but did not change in size during fuelling, we would expect no or little change in BMR in birds fed ad libitum with trout pellets. We show that cold-acclimated birds maintained higher body mass and food intake (8 and 51%) than warm-acclimated birds. Air temperature had no effect on fuelling rate, timing of fuelling, timing of peak body mass or BMR. During fuelling, average body mass increased by 32% while average BMR increased by 15% at peak of mass and 26% by the end of the experiment. Our results show that the small digestive organs characteristic of a trout pellet diet did not prevent BMR from increasing during premigratory fuelling. Our results are not consistent with the heat load hypothesis as currently formulated

Empirical evidence of the continuing improvement in cost efficiency of an endoscopic surveillance programme for gastric cancer in Singapore from 2004 to 2010

10.1186/1472-6963-13-139BMC Health Services Research131

Wild Skylarks Seasonally Modulate Energy Budgets but Maintain Energetically Costly Inflammatory Immune Responses throughout the Annual Cycle

A central hypothesis of ecological immunology is that immune defences are traded off against competing physiological and behavioural processes. During energetically demanding periods, birds are predicted to switch from expensive inflammatory responses to less costly immune responses. Acute phase responses (APRs) are a particularly costly form of immune defence, and, hence, seasonal modulations in APRs are expected. Yet, hypotheses about APR modulation remain untested in free-living organisms throughout a complete annual cycle. We studied seasonal modulations in the APRs and in the energy budgets of skylarks Alauda arvensis, a partial migrant bird from temperate zones that experiences substantial ecological changes during its annual cycle. We characterized throughout the annual cycle changes in their energy budgets by measuring basal metabolic rate (BMR) and body mass. We quantified APRs by measuring the effects of a lipopolysaccharide injection on metabolic rate, body mass, body temperature, and concentrations of glucose and ketone. Body mass and BMR were lowest during breeding, highest during winter and intermediate during spring migration, moult and autumn migration. Despite this variation in energy budgets, the magnitude of the APR, as measured by all variables, was similar in all annual cycle stages. Thus, while we find evidence that some annual cycle stages are relatively more energetically constrained, we find no support for the hypothesis that during these annual cycle stages birds compromise an immune defence that is itself energetically costly. We suggest that the ability to mount an APR may be so essential to survival in every annual cycle stage that skylarks do not trade off this costly form of defence with other annual cycle demands

Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study

Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of circulating IGF-I is bound to an acid-labile subunit and to one of six insulin-like growth factor binding proteins (IGFBPs), among which the most important are IGFBP-3 and IGFBP-1. Polymorphisms of the IGF1 gene and of genes encoding for the major IGF-I carriers may predict circulating levels of IGF-I and have an impact on cancer risk. We tested this hypothesis with a case–control study of 807 breast cancer patients and 1588 matched control subjects, nested within the European Prospective Investigation into Cancer and Nutrition. We genotyped 23 common single nucleotide polymorphisms in IGF1, IGFBP1, IGFBP3 and IGFALS, and measured serum levels of IGF-I and IGFBP-3 in samples of cases and controls. We found a weak but significant association of polymorphisms at the 5′ end of the IGF1 gene with breast cancer risk, particularly among women younger than 55 years, and a strong association of polymorphisms located in the 5′ end of IGFBP3 with circulating levels of IGFBP-3, which confirms previous findings. Common genetic variation in these candidate genes does not play a major role in altering breast cancer risk in Caucasians

Preparticipation screening in order to prevent sudden cardiac death: 'Italian design' for Dutch athletes?

Onderzoek naar de kosteneffectiviteit van een verplichte keuring naar hartafwijkingen bij sporters is niet realiseerbaar. Vanwege de kleine schaal waarop de aandoeningen voorkomen, moet een grote groep mensen worden onderzocht. Dit is praktisch moeilijk te verwezenlijken en kost veel geld. Een plotse hartdood bij jonge mensen (jonger dan 35 jaar) tijdens het sporten is meestal het gevolg van een aangeboren of erfelijke hartafwijking. Daarom gaan in Nederland stemmen op om, zoals in Italie, sporters die bij sportverenigingen zijn aangesloten verplicht te keuren op hartafwijkingen. Dergelijk onderzoek omvat een elektrocardiogram (ecg), een korte vragenlijst en een lichamelijk onderzoek. Dit blijkt uit een uitgebreide literatuurstudie van het RIVM in opdracht van de Vereniging voor Sportgeneeskunde. Een plotse hartdood bij jongeren is vrij zeldzaam. In Nederland komt het naar verwachting niet meer dan honderd keer per jaar tegenover een groot aantal sporters. De emotionele impact is evenwel groot. Een vrijwillige keuring met een ecg van sporters kan er zeker aan bijdragen dat erfelijke en aangeboren hartafwijkingen worden opgespoord die op jonge leeftijd tot een plotse hartdood leiden. Een ecg spoort echter niet alle hartafwijkingen op die aan een plotse hartdood ten grondslag liggen, zo blijkt uit de literatuurstudie. Ook zullen er veel 'foutpositieven' worden gevonden, waardoor veel mensen onnodig ongerust raken. Om meer zicht op de oorzaken van plotse hartdoden te krijgen, wordt aangeraden de bestaande maatregelen voort te zetten en uit te bouwen. Een voorbeeld is de registratie van plotse hartdoden bij sporters. Daarnaast is het raadzaam ecg-afwijkingen die bij de meeste intensieve sportbeoefenaars zijn te zien, nader te onderzoeken.Performing a properly designed study into the cost-effectiveness of a compulsory medical examination for competitive athletes to detect hidden cardiac disease is infeasible. Due to the rarity of the underlying disorders an unrealistically large number of individuals would need to be included. This would be difficult to realise and would be very expensive. Sudden cardiac death in young people (aged 35 years or under) during physical activity is usually caused by congenital or hereditary heart disease. For that reason, experts in the Netherlands have recommended to follow the example of Italy and introduce a mandatory preparticipation cardiac screening for all competitive athletes. Such a screening comprises an electrocardiogram (ECG), a short questionnaire and a physical examination. Such is the outcome of an extensive study of the literature carried out by the RIVM at the request of the Society for Sportsmedicine. Sudden cardiac death in young people is quite rare. In the Netherlands it probably occurs with a frequency of at most one hundred cases each year, compared to a large number of athletes. However, the emotional impact is great. A voluntary screening of athletes including an ECG can certainly contribute to the detection of hereditary or congenital diseases of the heart that may cause sudden cardiac death at a young age. However, an ECG will not identify all relevant heart disorders, as appears from the study. Moreover, many false positives will be found, causing unnecessary distress. In order to gain more insight into the causes of sudden cardiac death, it is recommended to continue and further elaborate the initiatives that have already been started. An example is a registry of sudden death in athletes. In addition it is advisable to further investigate ECG abnormalities among those engaged in intensive physical activity.Vereniging voor Sportgeneeskund