Indicators for the total number of melanocytic naevi : an adjunct for screening campaigns. Observational study on 292 patients.

BACKGROUND: The presence of multiple melanocytic naevi is a strong risk factor for melanoma. Use of the whole body naevus count to identify at-risk patients is impractical. OBJECTIVES: To (i) identify a valid anatomical predictor of total naevus count; (ii) determine the number of naevi that most accurately predict total naevus count above 25, 50 and 100; and (iii) evaluate determinants of multiple melanocytic naevi and atypical naevi. METHODS: Clinical data from 292 consecutive Spanish patients consulting for skin lesions requiring debriding were collected throughout 2009 and 2010. Correlations between site-specific and whole body naevus counts were analysed. Cut-offs to predict total naevus counts were determined using the area under the receiver operating characteristic curve. RESULTS: The studied population was young (median age 31 years, interquartile range 28-43). The naevus count on the right arm correlated best with the total nevus count (R(2) 0·80 for men, 0·86 for women). Presence of at least five naevi on the right arm was the strongest determinant of a total naevus count above 50 [odds ratio (OR) 34·4, 95% confidence interval (CI) 13·9-85·0] and of having at least one atypical naevus (OR 5·7, 95% CI 2·4-13·5). Cut-off values of 6, 8 and 11 naevi on the right arm best predicted total naevus count above 25, 50 and 100, respectively. CONCLUSIONS: Our results support the arm as a practical and reliable site to estimate the total naevus count when screening or phenotyping large populations. Threshold values for the number of naevi on the arm are proposed to help identify patients for melanoma screening.

A theoretical and practical study on linear reforms of dual taxes

We extend the linear reforms introduced by Pf¨ahler (1984) to the case of dual taxes. We study the relative effect that linear dual tax cuts have on the inequality of income distribution -a symmetrical study can be made for dual linear tax hikes-. We also introduce measures of the degree of progressivity for dual taxes and show that they can be connected to the Lorenz dominance criterion. Additionally, we study the tax liability elasticity of each of the reforms proposed. Finally, by means of a microsimulation model and a considerably large data set of taxpayers drawn from 2004 Spanish Income Tax Return population, 1) we compare different yield-equivalent tax cuts applied to the Spanish dual income tax and 2) we investigate how much income redistribution the dual tax reform (Act ‘35/2006’) introduced with respect to the previous tax.

PKS2: A link between phototropin signalling and auxin transport - a study on how plants sense and respond to light.

The blue light photoreceptors phototropins (phot1 and phot2 in Arabidopsis thaliana (L.)) carry out various light responses of great adaptive value that optimize plant growth. These processes include phototropism (the bending of an organ induced by unequal light distribution), chloroplast movements, stomatal opening, leaf flattening and solar tracking. The biochemical pathways controlling these important blue light responses are just starting to be elucidated. The PHYTOCHROME KINASE SUBSTRATE (PKS1-4) proteins - the subject of this research - have recently been identified as novel phototropism signalling components. PKS1 (the founding member of this family) interacts in a same complex in vivo with phot1 and the important phot1 signalling element NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3). This suggested that the PKS may act as early components of phot signalling. This work further investigates the role of this protein family during phototropin signalling Genetic experiments clearly showed that the PKS do not control chloroplast movements or stomatal opening. However, PKS2 plays a critical role with NPH3 during leaf flattening and solar tracking. Epistasis data indicated that both proteins act in phot1 and phot2 pathways, which is consistent with their in vivo interaction with both phototropins. Because phototropism, leaf flattening and solar tracking are developmental processes regulated by the hormone auxin, the role of PKS2 and NPH3 during auxin homeostasis was also investigated. Interestingly, PKS2 loss-of-function restores leaf flattening in the auxin transporter mutant aux1. Moreover, PKS2 and NPH3 are found in a same complex with AUX1 in vivo. Taken together, these results suggest that PKS2 may act with NPH3 as a connecting point between phot signalling and auxin transport. Further experiments were performed to explore the molecular mode of action of PKS2 and NPH3 in this process. The significance of these results is discussed.

Study on thermostabilizers for trivalent oral poliomyelitis vaccine

Different formulations of trivalent oral poliomyelitis vaccine were tested, in order to obtain better thermostability, reduce corrosion of machinery and improve production costs. Magnesium chloride, sucrose, arginine and 199-Hank's medium were used in the formulations. The most appropriate formulation was a mixture of MgCl2 and arginine, which was highly thermostable, and had low production costs. The low corrosive formulation was rejected, due to low thermostability on storage.

Gas emission during laparoscopic colorectal surgery using a bipolar vessel sealing device: A pilot study on four patients.

BACKGROUND: Dissection during laparoscopic surgery produces smoke containing potentially toxic substances. The aim of the present study was to analyze smoke samples produced during laparoscopic colon surgery using a bipolar vessel sealing device (LigaSuretrade mark). METHODS: Four consecutive patients undergoing left-sided colectomy were enrolled in this pilot study. Smoke was produced by the use of LigaSuretrade mark. Samples (5,5l) were evacuated from the pneumoperitoneum in a closed system into a reservoir. Analysis was performed with CO2-laser-based photoacoustic spectroscopy and confirmed by a Fourier-transform infrared spectrum. The detected spectra were compared to the available spectra of known toxins. RESULTS: Samples from four laparoscopic sigmoid resections were analyzed. No relevant differences were noted regarding patient and operation characteristics. The gas samples were stable over time proven by congruent control measurements as late as 24 h after sampling. The absorption spectra differed considerably between the patients. One broad absorption line at 100 ppm indicating H2O and several unknown molecules were detected. With a sensitivity of alpha min ca 10-5 cm-1 no known toxic substances like phenol or indole were identified. CONCLUSION: The use of a vessel sealing device during laparoscopic surgery does not produce known toxic substances in relevant quantity. Further studies are needed to identify unknown molecules and to analyze gas emission under various conditions.

The Impact of Information Provision on Agglomeration Bonus Performance: An Experimental Study on Local Networks

The Agglomeration Bonus (AB) is a mechanism to induce adjacent landowners to spatially coordinate their land use for the delivery of ecosystem services from farmland. This paper uses laboratory experiments to explore the performance of the AB in achieving the socially optimal land management configuration in a local network environment where the information available to subjects varies. The AB poses a coordination problem between two Nash equilibria: a Pareto dominant and a risk dominant equilibrium. The experiments indicate that if subjects are informed about both their direct and indirect neighbors’ actions, they are more likely to coordinate on the Pareto dominant equilibrium relative to the case where subjects have information about their direct neighbors’ action only. However, the extra information can only delay – and not prevent – the transition to the socially inferior risk dominant Nash equilibrium. In the long run, the AB mechanism may only be partially effective in enhancing delivery of ecosystem services on farming landscapes featuring local networks.

Theoretical study on receptor-G protein recognition: new insights into the mechanisms of the alpha1b-adrenergic recptor activation

This work compares the structural/dynamics features of the wild-type alb-adrenergic receptor (AR) with those of the D142A active mutant and the agonist-bound state. The two active receptor forms were compared in their isolated states as well as in their ability to form homodimers and to recognize the G alpha q beta 1 gamma 2 heterotrimer. The analysis of the isolated structures revealed that, although the mutation- and agonist-induced active states of the alpha 1b-AR are different, they, however, share several structural peculiarities including (a) the release of some constraining interactions found in the wild-type receptor and (b) the opening of a cytosolic crevice formed by the second and third intracellular loops and the cytosolic extensions of helices 5 and 6. Accordingly, also their tendency to form homodimers shows commonalties and differences. In fact, in both the active receptor forms, helix 6 plays a crucial role in mediating homodimerization. However, the homodimeric models result from different interhelical assemblies. On the same line of evidence, in both of the active receptor forms, the cytosolic opened crevice recognizes similar domains on the G protein. However, the docking solutions are differently populated and the receptor-G protein preorientation models suggest that the final complexes should be characterized by different interaction patterns.

The reasons for discrepancies in target volume delineation : a SASRO study on head-and-neck and prostate cancers.

PURPOSE: To understand the reasons for differences in the delineation of target volumes between physicians. MATERIAL AND METHODS: 18 Swiss radiooncology centers were invited to delineate volumes for one prostate and one head-and-neck case. In addition, a questionnaire was sent to evaluate the differences in the volume definition (GTV [gross tumor volume], CTV [clinical target volume], PTV [planning target volume]), the various estimated margins, and the nodes at risk. Coherence between drawn and stated margins by centers was calculated. The questionnaire also included a nonspecific series of questions regarding planning methods in each institution. RESULTS: Fairly large differences in the drawn volumes were seen between the centers in both cases and also in the definition of volumes. Correlation between drawn and stated margins was fair in the prostate case and poor in the head-and-neck case. The questionnaire revealed important differences in the planning methods between centers. CONCLUSION: These large differences could be explained by (1) a variable knowledge/interpretation of ICRU definitions, (2) variable interpretations of the potential microscopic extent, (3) difficulties in GTV identification, (4) differences in the concept, and (5) incoherence between theory (i.e., stated margins) and practice (i.e., drawn margins).

Clinical and pharmacogenetic study on smoking and smoking cessation

Currently, smoking cessation represents one of the main strategies to reduce the incidence of tobacco-related diseases in the population. Smoking can also influence pharmacotherapy through several pharmacokinetic or pharmacodynamic interactions. Some of the most concerned drugs are those metabolized by the cytochrome P450 (CYP) 1A2 enzyme (e.g. caffeine, theophylline, clozapine, olanzapine, duloxetine), whose activity is induced by the polycyclic aromatic hydrocarbons found in tobacco smoke. This can result in a clinically significant decrease in the pharmacological effect of the drugs and the need of higher doses in smokers. Conversely, upon smoking cessation, toxic plasma levels of the drugs can be reached. The main objective of this thesis was to study the interindividual variability in CYP1A2 induction in a large cohort of smokers, by measuring CYP1A2 activity before smoking cessation and one month later in continuously abstinent subjects. For this purpose, a clinical study was conducted, including 194 smokers from the general population who wished to participate in a smoking cessation program and therefore received medical counseling and substitution therapy (nicotine or varenicline). An analytical method for the simultaneous quantification of nicotine, its metabolites and varenicline in plasma was developed and validated using ultra performance liquid chromatography coupled with tandem mass spectrometry. This method was used to confirm abstinence at different time points during the follow-up. Moreover, it was used to determine plasma levels of the smoking cessation drugs, to be used in the study of their pharmacogenetics, which was the secondary objective of this thesis. High interindividual variability in CYP1A2 induction by smoking was observed, ranging from no change to approximately 7 times decreased CYP1A2 activity after smoking cessation. Several clinical and genetic factors were investigated in an attempt to explain this variability. Firstly, a significant influence of CYP1A2*1F and *1D alleles, of contraceptive use and of the number of cigarettes smoked per day on CYP1A2 induced activity was observed, and of CYP1A2*1F and the use of contraceptives on the basal activity. But no influence of these factors was found on CYP1A2 inducibility. Given that known genetic polymorphisms in CYP1A2 gene were shown to explain only poorly the observed variations in activity, additional genetic factors were studied. SNPs in the CYP oxidoreductase (POR) gene were found to influence CYP1A2 basal activity, but not the induction. Finally, a pathway-based approach allowed to identify SNPs in genes coding for nuclear receptors (CAR, RXRa, VDR, PXR) and induction-mediating receptors (AhR), which significantly influenced CYP1A2 inducibility and basal activity (SNPs in the gene coding for CAR and RXRa). As secondary objective of the study, the pharmacogenetics of nicotine and varenicline is being investigated. Therefore, the nicotine metabolite ratio is used in the attempt to better explain nicotine dependence and the failure/success of quitting smoking. A population pharmacokinetic model is being developed for varenicline, integrating clinical and genetic factors (genes coding for its metabolizing enzymes and transporters), with the purpose of trying to predict efficacy and side effects. These findings suggest that the influence of smoking on pharmacotherapy could be better managed by including clinical and possibly in the future genetic factors, in the assessment of the adaptations needed when a person starts or stops smoking.  - L'arrêt du tabac représente une des principales stratégies pour diminuer l'incidence des maladies causées par celui-ci. Le tabagisme peut influencer la thérapie médicamenteuse par des interactions pharmacocinétiques ou pharmacodynamiques. Parmi les médicaments concernés, il y a ceux métabolisés par le cytochrome P450 (CYP) 1A2 (caféine, théophylline, clozapine, olanzapine, duloxétine, etc), dont l'activité enzymatique est induite par les hydrocarbures aromatiques polycycliques présents dans la fumée de cigarette. Ceci peut se traduire par une diminution de l'effet pharmacologique du traitement et la nécessité d'augmenter les doses d'entretien chez les fumeurs. Au contraire, à l'arrêt de la cigarette, les taux plasmatiques des médicaments peuvent devenir toxiques. L'objectif principal de cette thèse était d'étudier la variabilité interindividuelle dans l'induction du CYP1A2 dans une large cohorte de fumeurs, par la mesure de l'activité du CYP1A2 avant l'arrêt de la cigarette, ainsi qu'un mois après chez les sujets abstinents. Pour ce faire, une étude clinique a été conduite, incluant 194 fumeurs de la population générale dans un programme d'arrêt du tabac offrant des consultations spécifiques et un traitement pharmacologique (nicotine ou varénicline). Une méthode analytique pour la quantification simultanée de la nicotine, ses métabolites et la varénicline dans le plasma par chromatographie liquide couplée à la spectrométrie de masse en tandem à été développée et validée. Cette méthode a été utilisée pour confirmer l'abstinence pendant l'étude et déterminer les taux plasmatiques des médicaments, dans le but d'étudier leur pharmacogénétique. Une grande variabilité interindividuelle dans l'induction du CYP1A2 par la fumée a été observée, parfois sans changement et pouvant aller jusqu'à une diminution d'environ 7 fois l'activité du CYP1A2 après l'arrêt de la cigarette. Plusieurs facteurs cliniques et génétiques ont été étudiés pour essayer d'expliquer cette variabilité. Tout d'abord, on a observé une influence significative: des allèles CYP1A2*1F et *1D, des contraceptifs et du nombre de cigarettes fumées par jour sur l'activité induite du CYP1A2, ainsi que l'influence de l'allèle *1F et des contraceptifs sur l'activité basale. Cependant, aucune influence de ces facteurs n'a été démontrée sur l'inductibilité du CYP1A2. Étant donné que les polymorphismes génétiques du CYP1A2 apportent peu de renseignements sur la variabilité de son activité, des facteurs génétiques supplémentaires ont été étudiés. Des polymorphismes dans le gène POR (CYP oxidoreductase) ont été associés à l'activité basale du CYP1A2, mais pas à l'induction. Finalement, une approche basée sur la voie de signalisation du CYP1A2 a permis d'identifier des polymorphismes dans des gènes codant pour des récepteurs nucléaires (CAR, RXRa, VDR, PXR) et d'autres liés à l'induction (AhR) qui influencent significativement l'inductibilité et l'activité basale (les SNPs du CAR et RXRa). L'objectif secondaire de cette étude était d'investiguer la pharmacogénétique de la nicotine et de la varénicline. Le ratio métabolique de la nicotine est utilisé pour mieux expliquer la dépendance à la nicotine et le succès/échec de l'arrêt de la cigarette. Un modèle pharmacocinétique de population est en cours de développement pour la varénicline, intégrant des facteurs cliniques et génétiques (gènes codant pour ses enzymes de métabolisme et transporteurs), pour tenter de prédire son efficacité et ses effets secondaires. Les résultats de cette thèse suggèrent que l'influence du tabagisme sur la pharmacothérapie serait mieux gérée par l'inclusion des facteurs cliniques et peut-être, dans le futur, génétiques, dans l'évaluation des adaptations nécessaires lorsqu'une personne fume ou arrête de fumer.  - l'arrêt du tabac représente une des principales stratégies pour diminuer l'incidence des maladies causées par celui-ci dans la population. Le tabagisme peut influencer les traitements médicamenteux, soit en modifiant leur élimination par l'organisme, soit en agissant sur leur mode d'action. Parmi les médicaments les plus concernés, on retrouve par exemple: la caféine, la théophylline, la clozapine, l'olanzapine, la duloxétine, dont l'élimination est accélérée par la fumée de cigarette (induction enzymatique). Ceci peut se traduire par une diminution de l'effet du traitement et la nécessité d'en augmenter les doses chez les fumeurs. Au contraire, à l'arrêt de la cigarette, on observe un ralentissement de la fonction enzymatique, qui a pour conséquence une augmentation du taux de médicament dans le sang, pouvant devenir toxique. L'objectif principal de cette thèse était d'étudier comment cette induction par le tabac varie dans une population de fumeurs, par la mesure de l'activité de l'enzyme avant l'arrêt de la cigarette, ainsi qu'un mois après chez les sujets abstinents. Pour ce faire, une étude clinique a été conduite, incluant 194 fumeurs de la population générale dans un programme d'arrêt du tabac offrant des consultations spécifiques et un traitement médicamenteux (nicotine ou varénicline). Une méthode analytique a été mise au point pour mesurer la quantité de nicotine, de ses produits de dégradation et de la varénicline dans le sang des participants à l'étude. De plus, cette méthode a été utilisée pour confirmer l'abstinence pendant l'étude. Une grande variabilité interindividuelle a été observée dans l'induction de l'enzyme par la fumée; il en résulte aucun changement d'activité chez certains sujets après l'arrêt de la cigarette, alors que pour d'autres elle peut être diminuée jusqu'à 7 fois. Plusieurs facteurs cliniques et génétiques ont été étudiés pour essayer d'expliquer cette variabilité. Premièrement, une influence sur l'activité de l'enzyme a été observée pour les contraceptifs hormonaux et le nombre de cigarettes fumées par jour, ainsi que pour certaines variations génétiques dans le gène codant pour l'enzyme d'intérêt, mais il η y a pas eu d'influence sur l'induction. Par la suite, des variations génétiques dans d'autres gènes influençant le fonctionnement de l'enzyme ont été associées soit avec son activité, soit avec son induction par le tabac. Finalement, l'étude propose également d'investiguer si le métabolisme de la nicotine a une influence sur la dépendance, les symptômes de sevrage et le succès/échec de l'arrêt de la cigarette. Des variations génétiques dans les gènes du métabolisme de la varénicline sont également étudiées en lien avec les quantités de varénicline mesurées dans le sang ainsi que les effets du médicament. Ceci permettra peut-être de prédire son efficacité et ses effets secondaires. Les résultats de cette thèse suggèrent que l'influence du tabagisme sur la thérapie médicamenteuse serait mieux gérée en tenant compte des facteurs cliniques et peut-être, dans le futur, de la génétique dans l'adaptation des traitements, que la personne soit fumeuse ou en phase d'arrêt.

A recombinant hybrid protein as antigen for an anti-blood stage malaria vaccine: a study on the conservation of a protective component

Recently we have shown that two hybrid proteins expressed in Escherichia coli confer protective immunity to Aotus monkeys against an experimental Plasmodium falciparum infection (Knapp et al., 1992). Both hybrid proteins carry a sequence containing amino acids 631 to 764 of the serine stretch protein SERP (Knapp et al., 1989b). We have studied the diversity of this SERP region in field isolates of P. falciparum. Genomic DNA was extracted from the blood of six donors from different endemic areas of Brazil and West Africa. The SERP region encoding amino acids 630 to 781 was amplified by polymerase chain reaction (PCR) and sequenced. Only conserved amino acid substitutions in maximally two positions of the analyzed SERP fragment could be detected which supports the suitability of this SERP region as a component of anti-blood stage malaria vaccine.

A study on the pathogenesis of human cerebral malaria and cerebral babesiosis

Cerebral complications are important, but poorly understood pathological features of infections caused by some species of Plasmodium and Babesia. Patients dying from P. falciparum were classified as cerebral or non-cerebral cases according to the cerebral malaria coma scale. Light microscopy revealed that cerebral microvessels of cerebral malaria patients were field with a mixture of parazited and unparazited erythrocytes, with 94% of the vessels showing parasitized red blood cell (PRBC) sequestration. Some degree of PRBC sequestration was also found in non-cerebral malaria patients, but the percentage of microvessls with sequestered PRBC was only 13% Electron microscopy demonstrated knobs on the membrane of PRBC that formed focal junctions with the capillary endothelium. A number of host cell molecules such as CD36, thrombospondim (TSP) and intracellular adhesion molecule I (ICAM-1) may function as endothelial cell surfacereports for P. falciparum-infected erythrocytes. Affinity labeling of CD36 and TSP to the PRBC surface showed these molecules specifically bind to the knobs. Babesia bovis infected erythrocytes procedure projections of the erythrocyte membrane that are similar to knobs. When brain tissue from B. bovis-infected cattle was examined, cerebral capillaries were packed with PRBC. Infected erythrocytes formed focal attachments with cerebral endothelial cells at the site of these knob-like projections. These findings indicate that cerebral pathology caused by B. bovis is similar to human cerebral malaria. A search for cytoadherence proteins in the endothelial cells may lead to a better understanding of the pathogenisis of cerebral babesiosis.