Introgression in peripheral populations and colonization shape the genetic structure of the coastal shrub Armeria pungens

The coastal shrub Armeria pungens has a disjunct Atlantic-Mediterranean distribution. The historic range expansion underlying this distribution was investigated using the nuclear internal transcribed spacer region, three plastid regions (namely trnL-F, trnS-fM and matK) and morphometric data. A highly diverse ancestral lineage was identified in southwest Portugal. More recently, two areas have been colonized: (1) Corsica and Sardinia, where disjunct Mediterranean populations have been established as a result of the long-distance dispersal of Portuguese genotypes, and (2) the southern part of the Atlantic range, Gulf of Cadiz, where a distinct lineage showing no genetic differentiation among populations occurs. Genetic consequences of colonization seem to have been more severe in the Gulf of Cadiz than in Corsica-Sardinia. Although significant genetic divergence is associated with low plastid diversity in the Gulf of Cadiz, in Corsica-Sardinia, the loss of plastid haplotypes was not accompanied by divergence from disjunct Portuguese source populations. In addition, in its northernmost and southernmost populations, A. pungens exhibited evidence for ancient or ongoing introgression from sympatric congeners. Introgression might have created novel genotypes able to expand beyond the latitudinal margins of the species or, alternatively, these genotypes may be the result of surfing of alleles from other species in demographic equilibrium into peripheral populations of A. pungens. Our results highlight the evolutionary significance of genetic drift following the colonization of new areas and the key role of introgression in range expansion.

Internationally adopted children: what vaccines should they receive?

It is of paramount importance to know the vaccination status in internationally adopted children, so that they can be correctly immunized. This study ascertains the seroprotection rate for vaccine-preventable diseases and the validity of the immunization cards in 637 adopted children. The absence of the immunization card (13% of children) correlated with a poor global vaccine protection. Children with immunization records (87%) had a better global seroprotection but the information obtained from the card did not accurately predict seroprotection for each particular antigen. The best variable to predict the status of seroprotection was the country of origin. The highest rate of protection was found in children from Eastern Europe and, in descending order, India, Latin America, China and Africa. General recommendations for immunization of internationally adopted children are difficult to establish. Actions for vaccination have to be mainly implemented on the basis of the existence of the immunization card and of the country of origin.

Lack of effect of the ghrelin gene-derived peptide obestatin on cardiomyocyte viability and metabolism

Obestatin is a recently discovered peptide encoded by the ghrelin gene that opposes ghrelin effects on food intake and gastrointestinal function. The biological activity of obestatin depends on amidation at its carboxyl terminus and on its postulated binding to the orphan G protein-coupled receptor 39 (GPR39). We have previously demonstrated that ghrelin is synthesized by cardiomyocytes and has direct effects on its viability. Our aim was to know if obestatin, derived from the same gene as ghrelin, also affects cardiomyocyte physiology. By RT-PCR and immunocytochemistry we have demonstrated that murine cardiomyocytes cultured in vitro and human atrial tissue express GPR39 receptor. Competitive binding studies with radioiodine 125I-labeled obestatin recognized specific binding sites for this peptide in the murine cardiomyocyte cell line HL-1. However, obestatin did not modify the cell cycle or viability of these cells, and it was not able to prevent the cytosine arabinoside-induced apoptosis of HL-1 cardiomyocytes, as assessed by Hoechst dye vital staining, flow cytometry analysis and determination of lactate dehydrogenase in the culture media. Finally, treatment with obestatin did not affect fatty acid or glucose uptake by HL-1 cardiomyocytes. In conclusion, obestatin is not a relevant metabolic or viability modifier for cardiomyocytes.

[Preventive care and health promotion in primary care: comparison between the views of Spanish and European doctors]

OBJECTIVE

Disease prevention and health promotion are important tasks in the daily practice of all general practitioners (GPs). The objective of this study was to explore the knowledge and attitudes of European and Spanish GPs in implementing evidence-based health promotion and disease prevention recommendations in primary care, to describe GPs' perceived barriers to implementing these recommendations, and to assess how GPs' own health behaviors affect their work with their patients.

DESIGN

A postal multinational survey was carried out from June 2000 to May 2001.

SETTING

A random sample of GPs listed from national colleges of each country. Participants. A total of 2082 GPs from 11 European countries participated in the survey. In Spain a total of 270 GPs participated.

RESULTS

Spanish GPs carried out more frequently most of the health promotion or disease prevention activities than the European GPs. Spanish GPs carried out less often those no evidence-based activities. The most important barrier reported was heavy workload/lack of time. Associations between personal health behaviour and attitudes to health promotion or activities in prevention were found. GPs who smoked felt less effective in helping patients to reduce tobacco consumption than non-smoking GPs (39.34% vs 48.18%; P < .01). GPs who exercised felt that they were more effective in helping patients to practice regular physical exercise than sedentary GPs (59.14% vs 49.70%;P < .01). No differences were observed for Spanish GPs.

CONCLUSIONS

Significant gaps between GP's knowledge and practices persist in the use of evidence-based recommendations for health promotion and disease prevention in primary care. Spanish GPs carried out more frequently evidence-base recommendations for health promotion and disease prevention by age and sex.

Healthy diet in primary care: views of general practitioners and nurses from Europe

BACKGROUND

Most of the national colleges of general practitioners (GPs) do not have their own dietary/nutritional tools, and GPs and nurses do not have the time, knowledge, or skills to advise their patients about desirable dietary practices.

OBJECTIVE

To assess the usefulness of a simple and practical guide on healthy diet to be used by European GPs and nurses.

DESIGN

A postal survey was mailed to 171 GPs and nurses from 12 European countries to obtain information about the usefulness of a guide on healthy diet developed by EUROPREV.

RESULTS

The perception of health professionals is that the main source of information on healthy diet for the population was the media. In all, 95% of GPs and nurses reported that the guide was useful; 93, 95, and 82% reported that the concepts were concise, easy to understand, and realistic, respectively. Also, 77% reported that the type of counselling recommended was feasible and could be applied, 94% reported that the implementation measures proposed could be effective and 88% reported that the Traditional Mediterranean Diet Pyramid is useful, but some concerns about the content were mentioned.

CONCLUSIONS

GPs and nurses from Europe think that a practical guide on healthy diet developed by EUROPREV could be used to advise patients in primary care, although the Traditional Mediterranean Diet Pyramid should be modified.

GH prevents apoptosis in cardiomyocytes cultured in vitro through a calcineurin-dependent mechanism

The use of GH to treat heart failure has received considerable attention in recent years. Although the mechanisms of its beneficial effects are unknown, it has been implicated in the regulation of apoptosis in several cell types, and cardiomyocyte apoptosis is known to occur in heart failure. We therefore decided to investigate whether GH protects cardiomyocytes from apoptosis. Preliminary experiments confirmed the expression of the GH receptor (GHR) gene in primary cultures of neonatal rat cardiomyocytes (PC), the specific binding of GH by HL-1 cardiomyocytes, and the GH-induced activation of GHR and its classical downstream effectors in the latter. That GH prevented the apoptosis of PC cells deprived of serum for 48 h was shown by DNA electrophoresis and by Hoechst staining assays in which GH reduced the percentage of cells undergoing apoptosis. Similarly, the TUNEL-evaluated pro-apoptotic effect of cytosine arabinoside (AraC) on HL-1 cells was almost totally prevented by pre-treatment with GH. Fluorescence-activated cell sorter (FACS) analysis showed apoptosis in 9.7% of HL-1 cells growing in normal medium, 21.1% of those treated with AraC and 13.9% of those treated with AraC+GH, and that GH increased the percentage of AraC-treated cells in the S/G(2)/M phase from 36.9% to 52.8%. GH did not modify IGF-I mRNA levels or IGF-I secretion in HL-1 cells treated with AraC, and the protection afforded by GH against AraC-induced apoptosis in HL-1 cells was not affected by the presence of anti-IGF-I antibodies, but was largely abolished by the calcineurin-inhibiting combination cyclosporin+FK506. GH also reduced AraC-induced phosphorylation of mitogen-activated protein kinase p38 (MAPK p38) in HL-1 cells. In summary, GH protects PC and HL-1 cells from apoptosis. This effect is not mediated by IGF-I and may involve MAPK p38 as well as calcineurin.

[Cerebral vasoreactivity and functional response in stroke: a study with functional MR]

INTRODUCTION

Lacunar infarcts are usually associated with anatomical and possibly functional changes in the walls of small blood vessels (penetrating arteries). The functional effect varies and is accompanied by cerebral adaptive/reorganizational changes. BOLD contrast, originated in the microvasculature (especially with ultra high magnetic fields) depends, in the end, on haemodynamic changes and is useful for exploring patterns of cerebral activation using fMR.

OBJECTIVES

To compare the temporal behaviour of the BOLD signal and the distribution of activation between a group of patients with no functional sequelae following a stroke and a control group, by using fMR at 3T.

RESULTS

The stroke group showed a smaller number of voxels activated, but this was not statistically significant. The patterns of activation, size of the sensor motor area (SM or ASM) and index of laterality were similar in both groups. In SM the BOLD response was 85% slower (p< 0.01) and 25% less (not statistically significant).

CONCLUSIONS

We found no differences in the patterns of activation of the two groups. This may be explained by the minimal lesions of the stroke group, which were insufficient to produce reorganizational/adaptive changes or by the great variety of responses. The temporal response of the BOLD response was different in the stroke group, probably as a result of the alteration in the haemodynamic response in relation to the underlying processes which damage the functional properties of the vascular wall. This difference in the BOLD response should be interpreted with caution, and borne in mind when interpreting activation in persons with vascular pathology. Further studies are necessary for better understanding of its significance.

[Functional magnetic resonance and the motor cortex II: measurement of activity]

INTRODUCTION

Functional magnetic resonance (fMR) with BOLD contrast has been shown to be a useful tool for clinical investigation. It is still uncertain which is the best way to establish the measures of activation for subsequent comparisons and their physiological significance.

OBJECTIVE

To explore the activation expressed as a function of different parameters.

PATIENTS AND METHODS

We did fMR with BOLD contrast at 3T and a motor paradigm in 14 healthy persons. The activation was expressed as the number of voxels activated within each area; their percentage in relation to the total number of voxels activated; z value; laterality index, speed and degree of temporal variation in the signal of these voxels.

RESULTS

Somatomotor area (SM) activated 121% more voxels than supplementary motor area (SMA), but their variation expressed with their standard variation was very large. The percentage of voxels activated was 163.6% greater in SM than in SMA. The laterality index increased at the expense of activation outside SM. The variation of the two relative measurements was less than the total number of voxels. The z value did not correlate with the degree of activity. The time course of the SMA signal was slightly different to SM.

CONCLUSIONS

Very high field fMR is very sensitive to changes in signal. The number of voxels activated varies considerably, so its use as a measurement of activity should be limited. Relative value, such as the index of laterality of the percentage of voxels may show less variability. The centre of mass and z value are stable figures but the physiological significance of the latter is not clear. The study of the temporal variation of the signal seems to be a potentially useful parameter with a certain degree of physiological significance, although better understanding and further analysis is necessary.

[Functional magnetic resonance and the cerebral cortex. 1: Group analysis]

INTRODUCTION

Various strategies are used to increase the sensitivity to activation in functional magnetic resonance (RMf) with bold contrast, including raised magnetic fields and group analysis. Although very important, study of the behaviour of the signal in a group (normal pattern) remains a problem in RMf.

OBJECTIVES

To study the behaviour of the signal in response to the motor paradigm using RMf with bold contrast at 3T in a group, by random effect analysis.

RESULTS

The areas of most solid activation were the somatomotor area, the contralateral SMA and ipsilateral cerebellar area. Other areas showed greater variability (the number of persons who activated them and their localization). Analysis of the group showed close correlation between individuals both in the areas mentioned and in the basal ganglia, and to a lesser extent in ipsilateral premotor and somatomotor areas. There was wide variability in prefrontal, frontal, dorsolateral and parietal areas.

CONCLUSIONS

There is some variation in activation (number and position of the activated areas). SM, SMA and cerebellum have a high degree of inter individual anatomofunctional concordance. Activity in the basal ganglia, in spite of high inter individual anatomofunctional correlation, may not be easy to observe. Some areas are activated in certain persons but not on analysis of the group. This shows inter individual functional and/or anatomical variability. Such variation in activation should be remembered in subsequent analysis. Group analysis is useful for showing collective patterns which determine the most consistent areas on which to base subsequent individual analysis.

[Introduction to functional magnetic resonance]

INTRODUCTION

During recent years we have seen the birth and development of a technique destined to revolutionize the world of the neurosciences, functional magnetic resonance (fMR). This new technique presents many challenges, both from the hardware point of view (little signal, relatively limited spatial and temporal resolution, artefacts, etc.) and of analysis (correction for movement, improved signal/noise ratio, statistical models used, etc.).

DEVELOPMENT

In this paper we review the most important aspects of fMR regarding artefacts, analysis and origin of the signal, based on the widely used BOLD contrast.

CONCLUSION

Although still at its beginnings, and in spite of aspects which need improvement, fMR appears to be a very useful tool both for clinical applications and investigation, and its use should be encouraged by normal MR imaging teams in everyday clinical practice.

[Magnetoencephalography: a new functional diagnostic technique for the neurosciences]

INTRODUCTION AND OBJECTIVES

We present a review on the technical, methodological and clinical advances in the functional study of the brain by means of magneto-encephalography. We look back the milestones of its historical development, through the work of the major research groups on this field and through our group's works and database (including doctoral thesis). Discussion on the neurophysiological and biomagnetism basis is provided as well as description of technical developments in superconducting detectors (SQUID, Superconducting Quantum Interference Device), signal processing, enhancement of noise-signal ratio and dipole modeling.

DEVELOPMENT

The need for brain functional studies has led to newer imaging procedures (functional magnetic resonance, PET, SPECT, etc.). Their spatial and temporal resolution and invasivity are compared to that of magneto-encephalography. Current equipment, up to 306 whole-head channels, may accurately detect cortical and subcortical activity. Apart from the physiological activity, it may be applied to a number of conditions: epilepsy (ictal, interictal and presurgical); dementia, movement disorders, stroke, eloquent cortex delimitation prior to tumour or lesion resection; learning disabilities and foetal studies.

CONCLUSIONS

Magnetoencephalography provides with an excellent temporal, very good spatial resolution, acquires in real-time, without references and minimal interference. It entails a great advance in the diagnostic approach in neurosciences.

A new clinical tool for gait evaluation in Parkinson's disease

This study was devised to check the feasibility and validity of a rating scale specifically designed to evaluate gait impairment in Parkinson's disease (RSGE). Demographic data, a brief questionnaire on general aspects influencing gait and mobility, a battery of scales (Barthel Index; Hoehn and Yahr staging; and Northwestern University Disability, Schwab and England, and Unified Parkinson's Disease Rating Scale [UPDRS]), and timed tests ("Up and Go" and "Steps x Seconds" tests) were recorded under protocol, as was the RSGE-Version 1.0 (23 items in four subscales). Fifty patients enrolled at two centers were included. Twenty-five (50%) were simultaneously (though independently) evaluated by three examiners, in order to determine the interrater reliability. The mean age of the patients was 67.6 +/- 11.16 years, with a mean 8.18 +/- 5.58 years of disease duration. Motor fluctuations were present in 48% of patients. The RSGE Cronbach's alpha was 0.94. Only the item "Dyskinesias" was not correlated with the RSGE total sum. The item "Axial rigidity" showed a fair interrater reliability (kappa = 0.30). However, most of the RSGE items (16/23, 70%) had kappa > or = 0.65. The convergent validity with the applied scales was very high (Spearman r = 0.74-0.90, p < 0.001). The highest correlation (0.90) was obtained with the UPDRS. Also, the RSGE correlation with timed tests was very satisfactory ("Up and Go" = 0.81; "Steps x Seconds" = 0.70; both, p < 0.001). Factor analysis of the RSGE disclosed four dimensions explaining 68% of the variance. The RSGE-Version 1.0 proved to be a valid instrument. The reliability of some items has to be improved, however.

Chromosomal substitution analysis of receptivity and sexual isolation in Drosophila melanogaster females

A chromosome substitution analysis was carried out in Drosophila melanogaster to elucidate the contribution of the X, II and III chromosomes to female receptivity, and to sexual isolation with its sibling species D. simulans. Two lines from the same base population with extreme phenotypes, the one showing high receptivity and weak isolation and the other showing low receptivity and strong isolation, were used. Genes involved in receptivity were located in chromosome III whereas those affecting sexual isolation were located in all the three chromosomes. These results indicate that the direct relationship between female receptivity and sexual isolation previously detected in D. melanogaster could be because of the occurrence of genes common to the two traits in the chromosome III.

Male mating speed in Drosophila melanogaster: differences in genetic architecture and in relative performance according to female genotype

From a critical review of the literature on mating speed in Drosophila, the importance of fast mating in male fitness is questioned. The genetic architecture of male mating speed (MMS) has been evaluated in D. melanogaster through a populational analysis and a full 5 x 5 diallel cross between inbred lines. The results emphasize the fundamental role of the female genotype in both the absolute and the relative MMS performances. Somewhat different genetic architectures for MMS are revealed according to the female used in the tests. It is suggested that different parts of the complex genetic system involved in the male's "behavioral sexual phenotype" are relevant depending on the female's characteristics, thus causing the heterogeneity in the MMS genetic architecture. An overall picture reveals a genetic system characterized by additivity, dominance for fast mating, and no influence of the X chromosome. There results do not support strong natural selection favoring fast mating in Drosophila males.

Bidirectional selection for female receptivity in Drosophila melanogaster

A wild population of Drosophila melanogaster was subjected to selection for high and low female receptivity. Selection was only applied in females on the basis of the mating times observed in a 30-min period. We applied a selection paradigm that allowed us to conclude that females unmated after 30 min correspond to the truncated upper tail of the distribution underlying mating times. Selection was successful, with mean mating times of about 5 min for the high lines, 35 min for the low lines, and 12 min for the control. Receptivity of the selection lines remained steady after 42 generations of relaxed selection, suggesting a lack of natural selection on receptivity in laboratory conditions. We also found a clear relationship between high or low receptivity and high or low frequency of hybridization with D. simulans males, emphasizing the role of female receptivity in maintaining isolation with its sibling species D. simulans.

Genetic basis for female receptivity in Drosophila melanogaster: a diallel study

Receptivity of sexually mature, virgin females, measured as the time to copulation, has been investigated. Two independent 5 x 5 diallel crosses were carried out, each one with a different male tester genotype. Interactions between male and female genotypes were detected because some lines appeared as dominant in one diallel and recessive in the other. The overall picture emerging from the analyses shows a genetic system for female receptivity characterized by additive genes, with dominance for high receptivity in one of the diallel crosses. This remarkable additive component does not support the action of natural selection favouring females with extreme values of receptivity, rather, the lack of intrasexual female competition for mates is suggested.

Selection for canalization at extra dorsocentral and scutellar bristles in Drosophila melanogaster

Direct artificial selection for a specific pattern, in the number and position of extra bristles, was carried out in a wild-type population of Drosophila melanogaster to canalize (estimated by probit width) the selected phenotypes. From the same population, independent lines were selected for extra dorsocentral bristles (lines D3 and D4) and for extra scutellar bristles (lines E2, E3, and E4). Differences at canalization between both dorsocentral and scutellar systems were detected. Results fit an independent control hypothesis for canalization, at two symmetrical extra bristles, in the main regions in which extra bristles appear.

Response to selection for increased hybridization between Drosophila melanogaster females and D. simulans males

Females of Drosophila melanogaster and males of D. simulans hybridizing in a nonchoice condition were artificially selected for 12 generations. The frequency of hybridization increased from 10% to 79%. Response to selection occurred in both species, particularly in D. melanogaster. Female receptivity was the primary sexual trait that accounted for breaking up sexual isolation in these species, but it remained unclear which elements of the D. simulans male courtship were involved.

Canalization at two extra scutellar bristles: artificial selection, chromosome analysis, and effect of temperature

Two isofemale lines (P1 and P2) from a wild-type population of Drosophila melanogaster were selected for an invariant phenotype, two symmetrical and anterior scutellar extra bristles. Both P1 and P2 lines responded quickly to direct selection for two extra bristles, but although this phenotype was canalized in the P2 line, it was not in the P1 line. This lack of canalization at two extra bristles, measured by probit width, is the first reported in the literature. Analysis of chromosomal contribution showed the P1 decanalized phenotype to be due to chromosome 2. Synthetic chromosomal combinations were tested at four development temperatures (17 degrees, 21 degrees, 24 degrees, and 30 degrees C), and no correlation was observed between canalization at two extra bristles measured by probit width and minimum phenotypic change due to different temperatures. In this test, development at the highest temperatures was accompanied by an increased tendency to return to the wild phenotype in the canalized phenotypes only, suggesting that this drastic change could be accounted for by the action of the wild-type canalizing system. Decanalized genotypes, or those canalizing at phenotypes other than the wild type, could be explained by mutations which, to a greater or lesser degree, alter the normal genetic system of canalization.

Selection for canalization at two extra dorsocentral bristles in Drosophila melanogaster

From 10 isofemale lines of D. melanogaster, the D2 line was established with the aim of obtaining an invariant phenotype at two extra dorsocentral bristles. Line D2 was also subdivided into two other lines, SA and ASD, based on their different bristle patterns. The SA line was selected for two symmetrical anterior extra bristles, and the ASD line was selected for two asymmetrical extra bristles, one anterior and one posterior. Only the SA line showed any canalizing response (estimated by the width of the probit transformation) at the two-extra-bristle class. Nevertheless, the results from the different lines were more consistent with the independent ones of both the anterior and posterior regions of the extra dorsocentral bristles. This analysis showed some independent genetic systems for each region, developmental canalization being at two extra symmetrical bristles per region in all the selected lines (D2, ASD, and SA). Therefore, this canalization did not depend directly on the extra-bristle positional pattern used in the selection. The wild-type canalizing system is suggested to explain the fast canalizing response in a phenotype that had not been previously canalized by natural selection.

Environmental sensitivity and heterosis for egg laying in Drosophila melanogaster

Genotype × temperature interactions for egg laying were studied in Drosophila melanogaster using two sets of half diallel crosses: one between inbred lines of the same geographic origin, and the other between established laboratory, newly derived inbred lines from different geographic origins. The sensitivity of most genotypes to changes in temperature was adequately described as a linear regression of mean in temperature. The regression coefficients (linear sensitivities) were heterogeneous between genotypes. Hybrids were more affected by temperature variation than were inbreds. All the heterogeneity of linear sensitivities was accounted for by a linear function of the genotypic means, which strongly suggests that a scale effect is responsible for the differences in sensitivity to temperature. In contrast, no general relationship was found between standard error deviation (sensitivity to small environmental changes) and mean performance between genotypes, although hybrids tended to be less variable than inbreds. This shows that the sensitivity to environmental variation depends not only on the genotype, but also on the nature of the environmental variation. The variability within temperatures may be affected by the general homeostasis of individual genotypes, while the variability between temperatures could be the result of genes directly affecting the trait and their multiplicative interaction with the environment.