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PubMed2000

[Two years follow-up of a heroin users cohort treated with high dosage buprenorphine. Results of the SPESUB study (pharmacoepidemiologic follow-up of general practice Subutex)].

BACKGROUND: Since February 1996, French GPs are allowed to prescribe high dosage buprenorphine for maintenance treatment of major opioid drug addiction. A prospective cohort of major opioid addicts was initiated in order to assess patient outcomes: follow-up, retention rate in treatment, drug use, intravenous injection and social situation evolution. METHODS: Each GP, known to be involved in drug user management, had to include the first 10 opioid drug addict patients to whom he prescribed high dosage buprenorphine, with a maximum inclusion period of 3 months. Patients were followed up for two years and a regular standardized information was collected (usual data on drug users and prescription modalities). RESULTS: Between May and July 1996, 919 patients (664 men and 255 women, mean age: 30 years) were included by 101 GPs. They had a long and serious history of drug addiction, important parallel consumption of cocaine, codeine and other illicit drugs and psychiatric problems (28% of definite problems and 45% of probable) and frequent hepatic conditions (hepatitis B: 23%, hepatitis C: 21%). Two years later, 55% of patients were still followed-up by the same GP and an additional 12% were followed by another GP or in a health care service (hospitalized or receiving methadone in a specialized centre). 13% were not followed, but GPs were able to describe their situation. 8% had been included by GPs who had dropped the study. Finally, 12% of patients were lost to follow-up. Among the 508 patients still followed-up by the same GP after 2 years, the substitution treatment rate was 84%. The dosage bracket had widened (inclusion: mean dosage=7.8 mg +/-4.5, minimum=0.8, maximum=28, median=8; after 2 years: mean=7.6 mg +/-5.4, minimum=0.4, maximum=28, median=8) and the duration of the prescription and dispensing had increased. Declaration of heroin intake in the previous month had fell from 40% to 11% and declaration of drug intake from 53% to 20%. Social situation had improved on average (housing conditions and work). There were 12 seroconversions for hepatitis B, 21 for hepatitis C and 4 for HIV. 14% of patients had declared intravenous injection of high dosage buprenorphine in the previous month. CONCLUSION: After two years of follow-up, 55% of patients were still followed-up by the same GP and an additional 12% was followed by another GP or in a health care service. Among patients still followed up by the same GP, a reduction of drug related harm (seroconversions for hepatitis B, hepatitis C and HIV) was observed.

Adult↗
PubMed1997

Genetic determination of paternity and variation in male reproductive success in two populations of rhesus macaques.

The fundamental framework for uncovering factors affecting the evolution of social behavior rests upon analyses of variation in reproductive success. In species where females mate with multiple males, paternity is invisible in the absence of genetic data. We determined paternity in two populations of rhesus macaques, Macaca mulatta, using both single locus and multilocus techniques. One troop, Group R, is one of four troops living on a 15 ha island (Cayo Santiago) off the coast of Puerto Rico, while the other troop, Group M, was translocated from Cayo Santiago to the Sabana Seca Field Station (Puerto Rico) in 1984. About a dozen human-derived short tandem repeat (STR) markers have been found to be polymorphic in the study of populations and provide the initial paternity determination. Final evaluation of paternity is then confirmed by multilocus DNA fingerprinting using synthetic oligonucleotide probes. Body condition, age, and dominance rank have an impact on male progeny production, while canine size does not. We suggest that nonagonistic competition in the form of sperm competition and endurance rivalry will modulate male reproductive success. A large body size among males provides them with an advantage in both sperm competition and endurance rivalry. Comparison of the two populations indicated that demographic, social, ecological, and morphological factors interact to regulate variation in reproductive success among male nonhuman primates.

Aging↗
PubMed2004

Worker honey bee pheromone regulation of foraging ontogeny.

The evolution of sociality has configured communication chemicals, called primer pheromones, which play key roles in regulating the organization of social life. Primer pheromones exert relatively slow effects that fundamentally alter developmental, physiological, and neural systems. Here, I demonstrate how substances extracted from the surface of foraging and young pre-foraging worker bees regulated age at onset of foraging, a developmental process. Hexane-extractable compounds washed from foraging workers increased foraging age compared with controls, whereas extracts of young pre-foraging workers decreased foraging age. This represents the first known direct demonstration of primer pheromone activity derived from adult worker bees.

Aging↗
PubMed2000

"You are what you eat": diet modifies cuticular hydrocarbons and nestmate recognition in the Argentine ant, Linepithema humile.

Nestmate recognition plays a key role in the behavior and evolution of social insects. We demonstrated that hydrocarbons are the chemical cues used in Argentine ant, Linepithema humile, nestmate recognition, and that these hydrocarbons can be acquired from insect prey. Consequently, Argentine ant cuticular hydrocarbon patterns reveal the same hydrocarbons present in their diet. Diet alters both the recognition cues present on the cuticular surface and the response of nestmates to this new colony odor, resulting in aggression between former nestmates reared on different insect prey.

Aggression↗
PubMed2005

[Maternal inheritance in a subsocial spider: web for collective prey capturing of the young].

Construction of a safe refuge is the first step toward the evolution of social organization in spiders. In the case of the subsocial spider Amaurobius Jerox (Araneae, Amaurobiidae), the young remain in the natal nest after consuming their mother's body (matriphagy). The benefit that the young could obtain from the maternal web was investigated in their collective prey capture. The results demonstrated the adaptive value of the maternal web. The prey capturing activity was more effective when the young were allowed to stay on the maternal web than when they used the web constructed by themselves. Maternal web may also provide a better transmission of information on prey state and clutch mates' activities, because more spiderlings were recruited to contact and hold the prey in a shorter period of time than when they were on a spiderling-constructed web. The young's inheritance of the maternal nest is probably one of the crucial ways in which the mother influences the post-maternal social period of the young.

Animals↗
PubMed2006

Disclosure decisions among pregnant women who received donor oocytes: a phenomenological study.

OBJECTIVE: To investigate the controversy surrounding disclosure among donor oocyte recipients. This controversy is escalating worldwide, yet little research has sought to understand the disclosure experience of pregnant, donor oocyte recipient women. This study aims to provide an in-depth description of the disclosure experience, and identify factors that were significant to recipient women which influenced their reasoning as they formulated disclosure decisions. DESIGN: Qualitative, naturalistic design, using a phenomenological approach. SETTING: The home or private office of the recipient woman. PATIENT(S): Donor oocyte recipient women between 9-23 weeks of gestation. RESULT(S): Disclosure decisions were influenced by multiple factors emerging from the women's values and beliefs and their social and cultural environment. Values and beliefs consisted of the right to know and the duty to protect. Social and cultural factors included social support, culture of the family, evolution of the social process, and personal testimonials. Women's age and selection of donor type were interrelated with disclosure decisions. CONCLUSION(S): Disclosing women voiced the right of the child to know, and perceived social and cultural factors as conducive to disclosure. Nondisclosing and undecided women emphasized protecting normative relationships, perceived a social stigma, and were unable to identify a benefit to disclosing. Women's age and choice of oocyte donor should be considered when counseling recipient women.

Adult↗
PubMed2005

[Adaptive behaviors to HIV risk of transmission in different populations].

Since the beginning of the HIV epidemic in France, surveys aimed at better understanding risk perceptions of HIV infection and preventive sexual behaviors have been implemented in the general population, and in populations such as IVDU and homosexual men, more concerned by risks of HIV transmission. The objective of this article is to describe these surveys, to present their main results and to assess what has been the overall impact of prevention campaigns on the adoption of preventive sexual behaviors in these populations. The results show that very early after the beginning of the AIDS epidemic, both general and homosexual populations have adopted preventive sexual behaviors, mainly increasing condom use and implementing other preventive strategies. However, with the introduction of HAART in 1996, a slackening of these preventive behaviors is noted. The use of condom is less frequent, especially in the youngest generations of both general and homosexual populations. On the opposite, among IVDU, the use of sterile syringes increased dramatically as soon as over-the-counter sales of syringes was authorized in 1987, as well as the adoption of ways other than intravenous to take drugs. Both have contributed to almost stop the HIV epidemic in this specific group. The results of these surveys show that the benefits of prevention campaigns are different between populations and are reversible. It is necessary to renew the messages, campaigns and programs of prevention with the renewal of generations. It is also necessary to adapt these messages to the new scientific data, and to the evolution of social and individual representations of the disease.

Antiretroviral Therapy, Highly Active↗
PubMed1998

A peptidergic basis for sexual behavior in mammals.

Vasopressin (VP) is a peptide neurotransmitter in the limbic system of rats. It is synthesized in the medial amygdaloid nucleus in the presence of sex steroids, transported to other limbic structures such as the hippocampus and septum and secreted there by a calcium-dependent process. In the hippocampus, VP acts on cerebral microvessels and local circuit interneurons. Its excitatory action on the inhibitory interneurons produces near-total shutdown of electrical activity of the efferent fibers of pyramidal cells, the projection neurons of the hippocampus. Stimulation of the medial amygdala and release of the endogenous VP duplicates these effects and, since they are blocked by ventricular application of a VP antagonist, the effects are almost certainly mediated by endogenous VP. Recording from the VP-containing cell bodies or of the hippocampal action of the peptide indicates that the system is selectively involved with the early stages of sexual behavior, specifically those appetitive behaviors that anticipate coitus. Stimulation of the VP cells produces alterations in sexual behavior in a manner consistent with the hypothesis that the medial amygdala organizes the appetitive phase of recognition of an appropriate partner and sexual arousal. This role for the medial amygdala complements the proposed role of nearby structures in the consummatory, reward and learned aspects of sexual behavior. Association between VP, oxytocin (OT) and homologs with sexual behavior is very widespread among vertebrates, including amphibians, reptiles, primates and humans. Humans and other primates display a phenomenon called 'concealed ovulation' that may have played a role in the evolution of social structures. The review concludes with a discussion of possible experimental strategies for evaluating the possible role of VP in concealed ovulation and other conditions in which sexual behavior occurs outside of estrus.

Animals↗
PubMed2000

Alternative reproductive strategies: a queen perspective in ants.

Ant colonies are commonly thought to have a stable and simple family structure, with one or a few egg-laying queens and their worker daughters. However, recent genetic studies reveal that the identity of breeding queens can vary over time within colonies. In several species, some queens are apparently specialized to enter established colonies instead of initiating a new colony on their own. The previously overlooked occurrence of queen turnover within colonies has important consequences not only on the genetic structure and nature of kin conflict within colonies, but also on the evolution of social parasitism.

Journal Article↗
PubMed1998

[Child of a single mother].

There were 658,000 one-parent families in France in 1968; there were 1,600,000 in 1994, disunity today being a component factor much more frequent than widowhood. The guarding parent is the mother in 87% of cases, and in 95% of cases for 0 to 4-year-old children. This mother is generally frustrated in her desire to rebuild the family. These families have suffered a rapid and important economic degradation in the past few years, the French one-parent families being victim of the evolution of social allowances which are more unfavourable for them than for other families. For many years, pediatric, pedopsychiatric and social disturbances observed in the children of these families have been ascribed to one-parent familyhood, the social environmental pressure having heavily influenced the results of the studies performed in this field. Recent studies do not permit implication of the one-parent familyhood as a specific factor and suggest this as a major role for the poverty of these families.

Child↗
PubMed2002

Genetic determination of the queen caste in an ant hybrid zone.

The question of how reproductives and sterile workers differentiate within eusocial groups has long been a core issue in sociobiology because it requires the loss of individual direct fitness in favor of indirect or group-level fitness gains. The evolution of social behavior requires that differentiation between workers and female reproductives be environmentally determined, because genetically determined sterility would be quickly eliminated. Nevertheless, we report clear evidence of genetic caste determination in populations of two seed harvester ant species common to the southwestern USA, Pogonomyrmex rugosus and Pogonomyrmex barbatus. The genetic differentiation between workers and queens is found only in areas of sympatry of the two species, and thus appears to arisen from hybridization. Our data suggest that this hybridization has had a profound historical effect on the caste determination systems and mating patterns of each of these species.

Animals↗
PubMed1982

Evolution of interference competition by individual, family, and group selection.

The necessary conditions for the evolution of social behaviors in a population with three levels of biological organization are derived by using a population genetic model (one locus, two alleles, random mating, discrete generations). Total selection on the behavior, Deltaq, is partitioned into the sum of three components: (i) Deltaq(I), selection between individuals within families; (ii) Deltaq(F), selection between families within groups; and (iii) Deltaq(G), selection between groups of families. I show that any level of selection can be made to operate in concert with or in opposition to any other, depending upon the fitness effects of the behavior. The implications of the model are discussed in relation to those adaptive explanations of phenotypic traits that generally consider selection to operate only between individuals.

Journal Article↗
PubMed1990

Trophallaxis in a communal halictine bee Lasioglossum (Chilalictus) erythrurum.

Food exchange by means of oral trophallaxis was confirmed for a communal halictine bee Lasioglossum (Chilalictus) erythrurum. These results demonstrate an independent evolution of trophallaxis in bees. The occurrence of trophallaxis in a communal species questions the role of trophallaxis in the evolution of sociality. Neutral arena encounters between one fed and one unfed female indicate that food exchange is not associated with familiarity. Donor females fed nestmates and nonnestmates in the same proportion, even when nonnestmates were from a separate nest aggregation located 7 km away. Such universal acceptance is expected if positive fitness benefits accrue from nearly all interactions with conspecifics in nature.

Journal Article↗
PubMed1997

Detecting immigration by using multilocus genotypes.

Immigration is an important force shaping the social structure, evolution, and genetics of populations. A statistical method is presented that uses multilocus genotypes to identify individuals who are immigrants, or have recent immigrant ancestry. The method is appropriate for use with allozymes, microsatellites, or restriction fragment length polymorphisms (RFLPs) and assumes linkage equilibrium among loci. Potential applications include studies of dispersal among natural populations of animals and plants, human evolutionary studies, and typing zoo animals of unknown origin (for use in captive breeding programs). The method is illustrated by analyzing RFLP genotypes in samples of humans from Australian, Japanese, New Guinean, and Senegalese populations. The test has power to detect immigrant ancestors, for these data, up to two generations in the past even though the overall differentiation of allele frequencies among populations is low.

Emigration and Immigration↗
PubMed2002

The origin of conditional logic: does a cheater detection module exist?

The domain-specific hypothesis of L. Cosmides (1989) and L. Cosmides and J. Tooby (1989, 1992) positing that conditional logic has its origin in the evolution of social exchange and in the detection of potential cheaters was tested against a more domain-general hypothesis positing that adult reasoning is logical and that errors in conditional reasoning arise from misunderstandings, not from a lack of logicality. The results of 5 experiments with undergraduate students (n = 682 for Experiments 1-4; n = 188 for Experiment 5), which involved a series of selection tasks that yielded specific predictions about participant performance, were not consistent with the cheater detection hypothesis. Findings supported the misunderstandings hypothesis and imply that adults possess general-purpose logical competence versus domain-specific modules.

Adult↗
PubMed2004

Obesity: the integrated roles of environment and genetics.

Obesity represents one of the most serious global health issues with approximately 310 million people presently affected. It develops because of a mismatch between energy intake and expenditure that results from behavior (feeding behavior and time spent active) and physiology (resting metabolism and expenditure when active). Both of these traits are affected by environmental and genetic factors. The dramatic increase in the numbers of obese people in Western societies reflects mostly changing environmental factors and is linked to reduced activity and perhaps also increased food intake. However, in all societies and subpopulations, there are both obese and nonobese subjects. These differences are primarily a consequence of genetic factors as is revealed by the high heritability for body mass index. Most researchers agree that energy balance and, hence, body weight are regulated phenomena. There is some disagreement about exactly how this regulation occurs. However, a common model is the "lipostatic" regulation system, whereby our energy stores generate signals that are compared with targets encoded in the brain, and differences between these drive our food intake levels, activity patterns, and resting and active metabolisms. Considerable advances were made in the last decade in understanding the molecular basis of this lipostatic system. Some obese people have high body weight because they have broken lipostats, but these are a rare minority. This suggests that for the majority of obese people, the lipostat is set at an inappropriately high level. When combined with exposure to an environment where there is ready availability of food at low energy costs to obtain it, obesity develops. The evolutionary background to how such a system might have evolved involves the evolution of social behavior, the harnessing of fire, and the development of weapons that effectively freed humans from the risks of predation. The lipostatic model not only explains why some people become obese whereas others do not, but also allows us to understand why energy-controlled diets do not work. Drug-based solutions to the obesity problem that work with the lipostat, rather than against it, are presently under development and will probably be in regular use within 5-10 y. However, several lines of evidence including genetic mapping studies of quantitative trait loci associated with obesity suggest that our present understanding of the regulatory system is still rudimentary. In particular, we know nothing about how the target body weight in the brain is encoded. As our understanding in this field advances, new drug targets are likely to emerge and allow us to treat this crippling disorder.

Adult↗
PubMed2005

Phase transition in random catalytic networks.

The notion of (auto)catalytic networks has become a cornerstone in understanding the possibility of a sudden dramatic increase of diversity in biological evolution as well as in the evolution of social and economical systems. Here we study catalytic random networks with respect to the final outcome diversity of products. We show that an analytical treatment of this long-standing problem is possible by mapping the problem onto a set of nonlinear recurrence equations. The solution of these equations shows a crucial dependence of the final number of products on the initial number of products and the density of catalytic production rules. For a fixed density of rules we can demonstrate the existence of a phase transition from a practically unpopulated regime to a fully populated and diverse one. The order parameter is the number of final products. We are able to fully understand the origin of this phase transition as a crossover from one set of solutions from a quadratic equation to the other. We observe a remarkable similarity of the solution of the system and the PVT diagrams in standard thermodynamics.

Algorithms↗
PubMed2004

Coexistence of the social types: genetic population structure in the ant Formica exsecta.

The ant Formica exsecta has two types of colonies that exist in sympatry but usually as separate subpopulations: colonies with simple social organization and single queens (M type) or colonial networks with multiple queens (P type). We used both nuclear (DNA microsatellites) and mitochondrial markers to study the transition between the social types, and the contribution of males and females in gene flow within and between the types. Our results showed that the social types had different spatial genetic structures. The M subpopulations formed a fairly uniform population, whereas the P subpopulations were, on average, more differentiated from each other than from the nearby M subpopulations and could have been locally established from the M-type colonies, followed by philopatric behavior and restricted emigration of females. Thus, the relationship between the two social types resembles that of source (M type) and sink (P type) populations. The comparison of mitochondrial (phiST) and nuclear (FST) differentiation indicates that the dispersal rate of males is four to five times larger than that of females both among the P-type subpopulations and between the social types. Our results suggest that evolution toward complex social organization can have an important effect on genetic population structure through changes in dispersal behavior associated with different sociogenetic organizations.

Animals↗