Reproduction impairments in metal-polluted environments and parental hormones: No evidence for a causal association in an experimental study in breeding feral pigeons exposed to lead and zinc.

Humans are responsible for land-cover changes resulting in the emission of hazardous chemical elements including metallic trace elements i.e. MTEs. As a consequence, urban wildlife is exposed to high concentrations of MTEs, which exposure is linked to reproductive impairments. MTE effects on reproduction outputs might result from MTE exposure disrupting the endocrine pathways involved in reproductive behaviours. In birds, there is strong evidence that prolactin, corticosterone and testosterone are all involved in the regulation of parental effort during incubation and chick rearing. Endocrine-disrupting chemicals might stimulate or inhibit the production of those hormones and consequently alter parental investment and reproductive success outcomes. We measured baseline corticosterone, prolactin and testosterone plasma levels, and the corticosterone stress response of breeding feral pigeons (Columba livia) experimentally exposed to ecologically relevant lead and/or zinc concentrations. Independently of lead and/or zinc exposure, male and female plasma levels of corticosterone and prolactin (but not testosterone) showed temporal variations along the reproduction stages (i.e. incubation, early rearing and late rearing). In addition, both hatching and fledging success were slightly correlated with corticosterone, prolactin and testosterone levels. However, our study did not find any influence of lead or zinc exposure on hormone levels, suggesting that MTE effects on reproductive outputs might not be explained by MTE-induced modifications of corticosterone, prolactin and testosterone-linked behaviours during incubation and rearing. Alternatively, MTE-induced reproductive impairments might result from MTE exposure having direct effects on offspring phenotypes or prenatal indirect effects on the embryo (e.g. maternal transfer of MTEs, hormones or immune compounds).

Pre-analytical issues in the haemostasis laboratory: guidance for the clinical laboratories.

Ensuring quality has become a daily requirement in laboratories. In haemostasis, even more than in other disciplines of biology, quality is determined by a pre-analytical step that encompasses all procedures, starting with the formulation of the medical question, and includes patient preparation, sample collection, handling, transportation, processing, and storage until time of analysis. This step, based on a variety of manual activities, is the most vulnerable part of the total testing process and is a major component of the reliability and validity of results in haemostasis and constitutes the most important source of erroneous or un-interpretable results. Pre-analytical errors may occur throughout the testing process and arise from unsuitable, inappropriate or wrongly handled procedures. Problems may arise during the collection of blood specimens such as misidentification of the sample, use of inadequate devices or needles, incorrect order of draw, prolonged tourniquet placing, unsuccessful attempts to locate the vein, incorrect use of additive tubes, collection of unsuitable samples for quality or quantity, inappropriate mixing of a sample, etc. Some factors can alter the result of a sample constituent after collection during transportation, preparation and storage. Laboratory errors can often have serious adverse consequences. Lack of standardized procedures for sample collection accounts for most of the errors encountered within the total testing process. They can also have clinical consequences as well as a significant impact on patient care, especially those related to specialized tests as these are often considered as "diagnostic". Controlling pre-analytical variables is critical since this has a direct influence on the quality of results and on their clinical reliability. The accurate standardization of the pre-analytical phase is of pivotal importance for achieving reliable results of coagulation tests and should reduce the side effects of the influence factors. This review is a summary of the most important recommendations regarding the importance of pre-analytical factors for coagulation testing and should be a tool to increase awareness about the importance of pre-analytical factors for coagulation testing.

Trace Metals Affect Early Maternal Transfer of Immune Components in the Feral Pigeon.

Maternal early transfers of immune components influence eggs' hatching probability and nestlings' survival. They depend on females' own immunity and, because they are costly, on their physiological state. Therefore, trace metals, whether toxic and immunosuppressive (e.g., lead, cadmium, etc.) or necessary and immunostimulant (e.g., zinc, copper, iron, etc.), are likely to affect the amount of immune components transferred into the eggs. It may also vary with plumage eumelanin level, which is known to be linked to immunity, to transfer of antibodies, and to metal detoxification. In feral pigeons (Columba livia) injected with an antigen and experimentally exposed to lead and/or zinc (two highly abundant trace metals in urban areas), we measured specific antibody transfer and concentrations of two antimicrobial proteins (lysozyme and ovotransferrin) in eggs. As expected, lead had negative effects on specific antibody transfer, while zinc positively affected lysozyme egg concentrations. Moreover, eggs from lead-exposed females exhibited higher ovotransferrin concentrations; because it binds metal ions, ovotransferrin may enable egg detoxification and embryo protection. Finally, eggs' lysozyme concentrations increased with plumage darkness of females not exposed to zinc, while the relation was opposite among zinc-exposed females, suggesting that benefits and costs of plumage melanism depend on trace metal environmental levels. Overall, our study underlines the potential ecotoxicological effects of trace metals on maternal transfers of immune components and the role of plumage melanism in modulating these effects.

Trace metals, melanin-based pigmentation and their interaction influence immune parameters in feral pigeons (Columba livia).

Understanding the effects of trace metals emitted by anthropogenic activities on wildlife is of great concern in urban ecology; yet, information on how they affect individuals, populations, communities and ecosystems remains scarce. In particular, trace metals may impact survival by altering the immune system response to parasites. Plumage melanin is assumed to influence the effects of trace metals on immunity owing to its ability to bind metal ions in feathers and its synthesis being coded by a pleiotropic gene. We thus hypothesized that trace metal exposure would interact with plumage colouration in shaping immune response. We experimentally investigated the interactive effect between exposure to an environmentally relevant range of zinc and/or lead and melanin-based plumage colouration on components of the immune system in feral pigeons (Columba livia). We found that zinc increased anti-keyhole limpet hemocyanin (KLH) IgY primary response maintenance, buffered the negative effect of lead on anti-KLH IgY secondary response maintenance and tended to increase T-cell mediated phytohaemagglutinin (PHA) skin response. Lead decreased the peak of the anti-KLH IgY secondary response. In addition, pheomelanic pigeons exhibited a higher secondary anti-KLH IgY response than did eumelanic ones. Finally, T-cell mediated PHA skin response decreased with increasing plumage eumelanin level of birds exposed to lead. Neither treatments nor plumage colouration correlated with endoparasite intensity. Overall, our study points out the effects of trace metals on some parameters of birds' immunity, independently from other confounding urbanization factors, and underlines the need to investigate their impacts on other life history traits and their consequences in the ecology and evolution of host-parasite interactions.

The adaptive function of melanin-based plumage coloration to trace metals.

Trace metals produced by anthropogenic activities are of major importance in urban areas and might constitute a new evolutionary force selecting for the ability to cope with their deleterious effects. Interestingly, melanin pigments are known to bind metal ions, thereby potentially sequestering them in inert body parts such as coat and feathers, and facilitating body detoxification. Thus, a more melanic plumage or coat coloration could bring a selective advantage for animals living in polluted areas. We tested this hypothesis by investigating the link between melanin-based coloration and zinc and lead concentrations in feathers of urban feral pigeons, both at capture time and after one year of captivity in standardized conditions. Results show that differently coloured pigeons had similar metal concentrations at capture time. Metal concentrations strongly decreased after one year in standardized conditions, and more melanic pigeons had higher concentrations of zinc (but not lead) in their feathers. This suggests that more melanic pigeons have a higher ability to store some metals in their feathers compared with their paler counterparts, which could explain their higher success in urbanized areas. Overall, this work suggests that trace metal pollution may exert new selective forces favouring more melanic phenotypes in polluted environments.

Ambient temperature influences birds' decisions to eat toxic prey.

Aposematic prey warn predators of their toxicity using conspicuous signals. However, predators regularly include aposematic prey in their diets, particularly when they are in a poor energetic state and in need of nutrients. We investigated whether or not an environmental factor, ambient temperature, could change the energetic state of predators and lead to an increased intake of prey that they know to contain toxins. We found that European starlings, Sturnus vulgaris, increased their consumption of mealworm, Tenebrio molitor, prey containing quinine (a mild toxin) when the ambient temperature was reduced below their thermoneutral zone from 20 °C to 6 °C. The birds differed in their sensitivity to changes in ambient temperature, with heavier birds increasing the number of toxic prey they ate more rapidly with decreasing temperature compared to birds with lower body mass. This could have been the result of their requiring more nutrients at lower temperatures or being better able to detoxify quinine. Taken together, our results suggest that conspicuous coloration may be more costly at lower temperatures, and that aposematic prey may need to invest more in chemical defences as temperatures decline. Our study also provides novel insights into what factors affect birds' decisions to eat toxic prey, and demonstrates that selection pressures acting on prey defences can vary with changing temperature across days, seasons, climes, and potentially in response to climate change.

[Syncopes and brief spells of feeling faint: value of Holter monitoring?]. / Syncopes et malaises brefs: utilité du Holter?

A retrospective study of Holter monitoring of 250 patients referred for syncope and short spells of dizziness suspected of being cardiac in origin was undertaken to assess the diagnostic value of the investigation. The arrhythmias observed were classified in 3 groups, significant, suspect and physiological with respect to their true or potential severity and to previously reported results of Holter monitoring in healthy subjects. The following arrhythmias were classified as significant: supraventricular tachycardia with a ventricular rate greater than or equal to 200 bpm; sustained ventricular tachycardia (greater than 30 s and greater than or equal to 150 bpm), bradycardia (less than bpm), sinus arrest (waking greater than 2 s sleeping greater than or equal to 6 s), complete AV block with wide QRS complexes and pacemaker dysfunction. The following arrhythmias were classified as suspect: paroxysmal supraventricular tachycardia with a ventricular rate less than 200 bpm, salvos of ventricular tachycardia (120 greater than 150 bpm); R/T phenomenon and doublets (greater than or equal to 50/24 hours), sinus arrest of 2 to 6 seconds during sleep, complete AV block with narrow QRS complexes or second degree Mobitz II block. This classification led to a diagnosis of certitude in 20 patients (5.7%) with significant arrhythmias concomitant with syncope or a minor form in only 5 cases, supraventricular tachycardia (4 cases), ventricular tachycardia (4 cases), AV block (5 cases), sinus arrest (3 cases), pacemaker dysfunction (4 cases); a diagnosis of presumption in 74 patients (21.1%) with suspect arrhythmias in the absence of syncope or minor equivalent.(ABSTRACT TRUNCATED AT 250 WORDS)

[Genesis of auricular fibrillation in the Wolff-Parkinson-White syndrome]. / Genèse de la fibrillation auriculaires dans le syndrome de Wolff-Parkinson-White.

Atrial fibrillation seems to be more common in the absence of associated cardiac disease in the Wolff-Parkinson-White syndrome (WPW) than in subjects of the same age without this condition. The aim of this study was to analyse the electrophysiological mechanism of AF and to establish its relationship to the accessory pathway. The series comprises 14 out of 51 patients with WPW undergoing classical endocavitary investigation associating the recording of cardiac potentials from the His bundle, right atrium (RA), left atrium (LA) via the coronary sinus and atrial and ventricular stimulation techniques. Three mechanisms of inducing AF were analysed : - AF triggered by RA stimulation : either by a premature extra stimulus or overdrive atrial pacing. In all cases, the accessory pathway was right sides. - AF triggered by overdrive ventricular pacing : three cases were left sided accessory pathways in which atrial desynchronisation was localised in the LA. - Conversion of reciprocating tachycardia to AF (9 cases). In 2 cases, this was preceded by a progressive acceleration of the heart rate. Of 3 left sided accessory pathways, the atrial desynchronisation was located in the LA in 2 cases. The factors which facilitate AF in THE WPW syndrome are discussed : increased atrial vulnerability, the role of the rapid return of ventricular excitation to the atria through the accessory pathway. Our observations suggest that the accessory pathway plays a role in the genesis of AF in the WPW syndrome.

[Electrophysiological effects of anti-arrhythmia agents in man. Attempt at classification]. / Effets électrophysiologiques des agents antiarythmiaques chez l'homme. Tentative de classification.

The electrophysiological effects of anti-arrhythmic drugs in man may be classified in three groups: -- Group I: comprising drugs whose characteristic action is on the AV node (beta blockers, verapamil, digitalis) The nodal conduction time (A-H interval) and refractory periods are increased. -- Group II: comprising drugs acting on the His-Purkinje system, the AV nodal conduction staying unchanged. This group has two sub-groups. Sub-group A: these drugs delay the His-Prukinje conduction (increased H-V interval). Examples are quinidine, procainamide, disopyramide, ajmaline, chloro-acetyl-ajmaline. In addition these drugs usually increase the atrial refractory periods and those of accessory pathways. Sub-group B: the His-Purkinje conduction is unchanged but the refractory periods are modified: lengthened (bretylium tosylate) or shortened (diphenylhydantoin, lignocaine, mexiletine). -- Group III: which includes amiodarone and aprindine whose effects are mixed: on the one hand AV nodal depression, and on the other, alteration of the His-Purkinje conduction manifested by an increased H-V internal (aprindine) or refractory periods (amiodarone). These preparations also increase the refractory periods of accessory AV pathways and amiodarone increase the refractory periods of the atria. This type of classification could help towards a more rational clinical approach to the use of anti-arrhythmic drugs.

[Electrophysiological study on mexiletine in man with reference to dose-response relation]. / Etude électrophysiologique de la méxilétine chez l'homme avec référence à la relation dose-effet.

The electrophysiological properties of Mexiletine were investigated by endocavitary His Bundle recording and programmed electrical stimulation of the heart in 30 patients. Differing dosage (2, 2.7 and 3.4 mg/kg) were given intravenously in 3 groups of 10 patients. The effects on the length of the sinus cycle, conduction intervals and cardiac refractory periods were observed and the following results obtained : 1. Sinus rhythm increased at all dosages but this effect was much more pronounced with 3.4 mg/kg dosage (--12.8% +/- 2.81% : : % shortening of sinus cycle with respect to the basal cycle +/- SD, p less than 0.005); 2. Atrioventricular nodal conduction time (A-H interval) decreased, the effect being more marked with the larger dose regimes; 3.His-Pirkinje conduction time (H-V interval) unaltered except in 3 cases where it increased by 5 ms after injection of 2.7 mg/kg; 4. Relative refractory period of His-Parkinje system shortened, this effect also being more pronounced with the larger doses ( --3.75 +/- 0.25% :2.7 mg/kg, p less than 0,001; -- 7 +/- 1.46% 3.4 mg/kg, p less than 0.005). In conclusion, the changes observed in the His-Purkinje system after mexiletine were similar to those of Lignocaine and Diphenylhydantoin. The drug also appears to have a marked vagal inhibitory effect as shown by the acceleration of the sinus rhythm and reduced atrioventricular conduction times.

[Electrophysiological effects of chloroacetyl ajmaline in Wolff-Parkinson-White syndrome]. / Etude des effets électrophysiologiques de la chloro-acétyl-ajmaline dans le syndrome de Wolff-Parkinson-White.

The electrophysiological effects of chloro-acetyl-ajmaline in the Wolff-Parkinson-White syndrome have been studied in 7 patients after an intravenous dose of 1.5 mg/kg of the drug. Preexcitation was abolished in 3 cases, while 3 other subjects showed a slight increase in effective refractory period of the abnormal route of excitation (a mean of 13 ms). The possibility of bringing about a reciprocal rhythm was removed in one case out of two. During tachycardia, chloro-acetyl-ajmaline produced significant lengthening of the ventriculo-atrial conduction time (p less than 0.05). These results show the usefulness of chloro-acetyl-ajmaline in the control of the arrhythmias associated with the Wolff-Parkinson-White syndrome.

Re-entry via Mahaim fibres as a possible basis for tachycardia.

Paroxysmal tachycardia with widened QRS complexes was recorded in a 21-year-old man. In sinus rhythm there was no evidence of pre-excitation. His bundle studies revealed an abnormally short HV interval of 30 ms. Premature atrial stimuli produced an increased PR interval. At short coupling intervals the His bundle activity became incorporated within the QRS complex. Concurrently, a left bundle-branch block pattern appeared identical to that seen during tachycardia. Closely coupled ventricular extrastimuli initiated a tachycardia identical to the initial episode. A re-entry mechanism via anterograde Mahaim fibres and retrograde His bundle -AV node pathway is postulated.

[Action of chloro-acetyl-ajmaline on the electrical properties of the human heart]. / Action de la chloro-acétyl-ajmaline sur les propriétés électriques du coeur humain.

The electrophysiological changes caused by the intra-atrial injection of 1.5 mg/kg of chloro-acetyl-ajmaline were studied in 23 patients by recording the His potential and by the stimulustest method. The length of the basal cycle being kept constant by atrial stimulation, measurements were made before and after the injection, on the one hand of the -VA node conduction time (A-H interval) and the infra-His conduction time (H-V interval) and on the other of the refractory periods of the right auricle, A-V node, and the His-Purkinje system. The effective refarctory period of the right ventricle was determined under pace-making of the ventricle. Finally, the variability of the sinus rate was measured. The results were as follows: 1. The sinus cycle was significantly shortened after administration of the drug (p 0.001); 2. The conduction time and refractory periods of the A-V node were not influenced by this substance; 3. The H-V interval was increased in 20 patients by an average of 11 ms (p less than 0.001). The relative refractory period of the His-Purkinje system was reduced in 4 cases out of 7 by 21 ms (p less than 0.05); the effective refractory period in one case showed a reduction of more than 45 ms. These findings will serve as a base line for assessing the anti-arrhythmic action of chloro-acetyl-ajmaline.