Répartiteur de dose des médicaments radiopharmaceutiques : contrôle qualité sur deux sites hospitaliers et comparaison avec la législation en vigueur en France

An increasing number of nuclear medicine departments are equipped with automated measurement systems for the preparation of radiopharmaceuticals, with the main aim of minimising technician's irradiation. However, the automatic measurement of the patient activity differs from the manual measurement in material and method. In this context, the objective of the present study was to test the performances of one of these systems, the Unidose by TRASIS^®, in two newly equipped hospitals. The particularity of these systems is they are made up of two dose calibrators: the entrance calibrator (well chamber) and the exit calibrator (probe). Controls were performed on both of these dose calibrators. The results obtained, as well as the methodology employed, were then compared with the regulatory requirements in France. The results found are coherent between the two sites and have highlighted several non-conformities compared to the current regulations, part of which concerning the carpule dose calibrator, which is actually a probe. These results raise the question of a suitable regulation for the new automated measurement systems in nuclear medicine.     

β-carotene ameliorates CUS-induced circadian alternations of locomotor activity and melatonin patterns in rats

Circadian and stress systems have a crucial role in adaptation of organisms to environmental challenges. This study investigates the ability of Oscillatoria brevis (O. brevis) β-carotene extract (βC) in modulating the circadian alternations of locomotor activity (LA) and serum melatonin (M) rhythms under chronic unpredictable stress (CUS) in rats. Twenty rats (5 rats/group) were used in monitoring LA using running wheels. Eighty rats (20 rats/group) were used in observing circadian serum M profile. Rats were randomly divided into four groups, viz. control, βC-treated, CUS-exposed, and “βC-treated&CUS-exposed” groups. CUS-exposure was applied for 21 days. One hour before exposure, βC was daily administered (10 mg/kg), intraperitoneally (IP). Blood was sampled at 6-h intervals for 5 rats/time point at Zeitgeber (ZT) 3, 9, 15, and 21. Results demonstrated that unstressed rats exhibited circadian M pattern and nocturnal LA rhythm with acrophase around ZT 21 and ZT 15, respectively. CUS-exposure revealed a disturbance in these patterns. Phase shifting of M and LA profiles was recorded. A decrease M acrophase and a significant decrease in LA (p < 0.05) were recorded at ZT 9. Daily βC administration in stressed rats modulates the CRs alternation induced by CUS. It may be concluded that βC ameliorated the induced alternations in circadian rhythms.     

Social isolation of mice: activity rhythm changes and the expression of clock

Social isolation usually affects the physical and mental health of the human and produces depression, whether it may relate with circadian rhythm still remains to be investigated. Two groups of mice were employed to this experiment to continuously monitoring their activities in a dark environment. Immunofluorescence was used to show the expression of the circadian clock gene in two groups of mice. The results demonstrate that the social isolation leads to decrease of mouse activities, phase advance of rhythm relatively and down-regulated of clock gene expression. We conclude that social isolation can affect the physiological function and the normal physiological rhythm of mice, which may be related to depression.     

Geographic variation in 'costs of reproduction' in the scincid lizard Lampropholis guichenoti

1. A major focus of life-history research has been the analysis of reproductive effort (RE). However, while clearly defined in theory, RE has proved very difficult to measure. Consequently, researchers have looked for indices that estimate the components of RE. Uncritical use of indices of reproductive investment, such as measures of costs of reproduction, without verification of the underlying assumptions of the link between these traits, may lead to spurious conclusions. In this paper, the common assumption that the physical burden of the clutch impairs locomotor ability in gravid reptiles is examined.
2. Two neighbouring populations of Australian scincid lizards ( Lampropholis guichenoti) are similar in adult body sizes, body shapes and reproductive output (egg sizes, clutch sizes, relative clutch masses).
3. Despite morphological and reproductive similarities, the effects of pregnancy on maternal locomotor ability (running speeds, as measured in a laboratory raceway) differed dramatically between the two populations.
4. Lizards from the two populations ran at similar speeds when nongravid (i.e. after egg-laying), but pregnancy significantly reduced running speeds in one population and increased them in the other. Thus, superficial similarities in body size and reproductive output masked a strong divergence in the locomotor 'costs' of reproduction.
5. Caution is advised if using simple measures of reproductive output (e.g. relative clutch mass) as indices of reproductive effort, or to generalize results even among conspecific populations.     

单侧前庭神经切断后猫运动方式的改变和补偿

本工作首次将一种运动分析系统,即视觉自动电视摄相信息处理系统（ｏｐｔｉｃａｌａｕｔｏｍａｔｉｃＴＶ－ｉｍａｇｅｐｒｏｃｅｓｓｏｒ,Ｅ．Ｌ．Ｉ．Ｔ．Ｅｓｙｓｔｅｍ）用于动物运动方式的定量分析,比较了猫一侧前庭神经切断前后在跨越转动横梁测试中运动方式的变化。结果如下：在横梁静止条件下,猫述后行走的初始身高明显下降,步距变短,步 频降低,呈缓慢的蹒中山步态,继而各参量逐渐增加,分别在术后４５和７０ｄ恢复     

Eggs in autumn: responses to declining incubation temperatures by the eggs of montane lizards

Facultative hatching in response to environmental cues may increase the viability of offspring, if the cue that stimulates hatching also predicts the negative consequences of delayed emergence. Declining incubation temperatures might provide such a cue for montane lizards, because eggs that fail to hatch before winter will perish in the nest. I tested this idea by incubating eggs of an alpine scincid lizard ( Bassiana duperreyi ) in the laboratory. For the first half of the incubation period the eggs were kept at nest temperatures typical of those experienced in summer in the field (daily cycle of 18 ± 7.5°C). I then transferred eggs at weekly intervals into cooler regimes (either 15 ± 7.5°C; or with daytime temperatures unchanged but dropping to 0°C overnight). Contrary to prediction, the eggs did not hatch early. However, transfer to lower temperatures caused only a relatively short delay in hatching, because of a virtual temperature-independence of developmental rates late (but not early) in incubation. Decreasing incubation temperatures also modified hatchling running speeds and post-hatching growth rates, even if the thermal decrease occurred only shortly before the usual time of hatching. These processes plausibly affect hatchling fitness in cold-climate reptiles, and might be adaptations to montane habitats. Alternatively, they may prove to be widespread in other (warmer-climate) reptile taxa, in which case no adaptive hypothesis need be proposed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 71–77.     

Effect of temperature on circadian rhythm controlling the crepuscular activity of the burying beetle Nicrophorus quadripunctatus Kraatz (Coleoptera: Silphidae)

Locomotor activity rhythm was examined at various temperatures under a 16 h light : 8 h dark photoperiod (LD 16:8) or LD 12:12 using adults of the burying beetle Nicrophorus quadripunctatus. At 20°C, the locomotor activity of the beetles showed a bimodal daily pattern with two peaks around lights on and lights off under both photoperiods. This bimodal activity rhythm persisted under constant darkness; therefore, the activity of adult N. quadripunctatus is controlled by a circadian clock. Adults showed a bimodal activity pattern for temperatures ranging from 15 to 25°C. The evening peak of the daily activity was earlier at lower temperatures. These findings suggest that in the field, N. quadripunctatus shows crepuscular activity, and is active earlier in the afternoon in cooler seasons. In this species, therefore, temperature appears to play an important role in the determination of daily activity patterns.     

Investigating thermal acclimation effects before and after a cold shock in Drosophila melanogaster using behavioural assays

Acclimation to environmental change can impose both costs and benefits to organisms. In this study we explored to what extent locomotor behaviour of Drosophila melanogaster is influenced by developmental temperature and adult temperature in both the laboratory and the field. Following development at 15, 25, or 31 °C, adult flies were tested for locomotor activity at all developmental temperatures in the laboratory before and after exposure to a cold shock and in the field for their ability to locate resources after a cold shock. Both test (15, 25, and 31 °C) and developmental temperatures strongly affected locomoter activity, with flies developed at 25 °C having the highest activity at all three test temperatures before the cold shock. After the cold shock flies developed at 15 °C had higher activity compared with flies developed at 25 and 31 °C when tested at 15 and 25 °C, and flies developed at 25 °C had the highest activity when tested at 31 °C. Furthermore, flies developed at 31 °C showed longer recovery times following the cold shock at test temperatures of 15 and 25 °C. However, flies acclimated at 15 °C during development did not recover faster at 15 and 25 °C compared with flies developed at 25 °C. There were no significant correlations between recovery time and locomotor activity at any of the test temperatures. Flies developed at 15 °C and exposed to a cold shock before release in the field were much more successful in locating a resource at low field temperatures compared with flies developed at 25 and 31 °C. Our results provide support for both the beneficial acclimation hypothesis and the optimal developmental temperature hypothesis, but the results are highly context dependent and change with the temperature experienced by the individual during its lifetime.     

A comparison of species diversity estimators

Although having been much criticized, diversity indices are still widely used in animal and plant ecology to evaluate, survey, and conserve ecosystems. It is possible to quantify biodiversity by using estimators for which statistical characteristics and performance are, as yet, poorly defined. In the present study, four of the most frequently used diversity indices were compared: the Shannon index, the Simpson index, the Camargo eveness index, and the Pielou regularity index. Comparisons were performed by simulating the Zipf–Mandelbrot parametric model and estimating three statistics of these indices, i.e., the relative bias, the coefficient of variation, and the relative root-mean-squared error. Analysis of variance was used to determine which of the factors contributed most to the observed variation in the four diversity estimators: abundance distribution model or sample size. The results have revealed that the Camargo eveness index tends to demonstrate a high bias and a large relative root-mean-squared error whereas the Simpson index is least biased and the Shannon index shows a smaller relative root-mean-squared error, regardless of the abundance distribution model used and even when sample size is small. Shannon and Pielou estimators are sensitive to changes in species abundance pattern and present a nonnegligible bias for small sample sizes (<1000 individuals). Received: May 8, 1998 / Accepted: May 6, 1999     

Incorporating Motion into Investigations of mimicry

During the past thirty years, natural selection due to predation has been investigated with regard to prey motion in three areas that are relevant to the evolution of mimicry: (1) anti-apostatic selection, (2) locomotor mimicry, and (3) escape mimicry. Anti-apostatic selection, or selection against the odd individuals, arises when prey are at very high densities or when prey are Müllerian mimics. When prey are at high densities, motion of the prey increases selection against odd individuals. When the prey are Müllerian mimics, motion may also play an important role in strengthening selection against odd individuals. This may explain locomotor mimicry between Müllerian mimics. Locomotor mimicry arises when two distantly-related prey species appear alike in behaviour, and there is a corresponding suite of morphological, physiological, and biomechanical traits that the prey have in common. Locomotor mimicry has been demonstrated in Müllerian mimics. It is also predicted to occur in Batesian mimics but with important limitations due to selection by the predator for the prey to maintain the ability to escape if detected. Locomotor mimicry may also occur between palatable species that are alike as a result of unprofitable prey (or escape) mimicry. Escape mimicry arises when prey are difficult to capture. By frustration learning, the predator associates the colour of the prey with unprofitability. In all three instances, dis-similarity in colour or motion probably increases selection against the odd individual. In addition, the interaction of colour and motion gives rise to greater reliability of the signals to a specialist predator. However for a generalist predator, multiple component signals of the prey lead to errors in signal perception and greater risk of cheating. This revised version was published online in July 2006 with corrections to the Cover Date.