Sexual self-efficacy and sexual communication among adolescent girls: moderated mediation results from a randomized controlled trial

OBJECTIVE

Guided by the Operating Conditions Framework, the goal of this study was to identify how and for whom an online sexual health program called Health Education and Relationship Training (HEART) worked.

DESIGN

Data come from a randomized controlled trial among 198 U.S. high school girls who completed HEART or an attention-matched control. We conducted mediation and moderated mediation models to determine if sexual self-efficacy was a mediator and if program acceptability and sexual activity status were moderators of HEART efficacy.

MAIN OUTCOME MEASURE

Sexual communication skills were assessed with a behavioral role-play task.

RESULTS

HEART significantly improved sexual communication skills. These effects were fully mediated through sexual self-efficacy. Specifically, HEART improved sexual self-efficacy which in turn increased sexual communication skills. Also, when participants liked the program more, the effect of HEART on sexual self-efficacy was stronger. Further, among girls who had engaged in sexual activity, sexual self-efficacy was significantly associated with sexual communication skills.

CONCLUSION

This study provides insights into the mechanisms of behavior change underlying HEART. Results highlight the need to further 'unpack' the effects of other sexual health programs, as we showed that programs may work better under certain conditions.

Parents' attitudes towards the content of sex education in the USA: Associations with religiosity and political orientation

While most parents support their adolescents receiving school-based sex education, there is variability in which sex education topics receive the most support from parents. Conservative political orientation and greater religiosity have been independently associated with parents' lack of support for school-based sex education; however, no studies have examined the intersection of these two factors. The three goals of this study were to: 1) identify how specific sexual education topics cluster together to form content areas; 2) examine if religiosity and political orientation are uniquely associated with these content areas; and 3) examine if political orientation moderates the relationship between parents' religiosity and their perceived importance for the specific sex education content areas. Participants were a national sample of 881 US parents. The sex education topics clustered into three content areas: Factual Knowledge (e.g., STI transmission), Practical Skills (e.g., how to access condoms), and Pleasure and Identity (e.g., pleasurable aspects of sex). Politically conservative and more religious parents reported the lowest perceived importance for each content area. Importantly, these main effects were qualified by a significant interaction: parents who reported both political conservativism and high levels of religiosity reported the lowest perceived importance for these three content areas being taught.

Behavioral Measures to Assess Adolescent Sexual Communication with Partners: A Scoping Review and Call for Further Studies

Sexual communication with partners is important for adolescents' sexual and socioemotional well-being. Behavioral assessments of partner sexual communication capture the complex and nuanced process of communication and are commonly used with adults, yet the existing literature among adolescents overwhelmingly relies on self-report measures. In the current paper, we reviewed the literature on adolescent partner sexual communication, identifying 14 studies including 2,043 participants (M age = 16) that used behavioral assessments (i.e., dyadic observations, role-plays with confederates, role-plays with vignettes). We also identify key gaps in the current literature: First, only one study recruited couples; studies that assessed dyadic interactions largely relied on confederates. Second, assessments often assumed that participants engaged in heterosexual sex, and no studies specifically recruited LGBTQ+ adolescents. Third, behavioral tasks often involved assumptions of participants' sexual goals (e.g., desire to refuse sex) and focused almost exclusively on sexual refusal and condom negotiation. Additionally, coding schemes lacked standardization and micro-analytic strategies (e.g., coding change over time). Finally, observational methods have been almost exclusively used to assess intervention efficacy, rather than to understand associations between behaviorally-assessed communication skills and sexual outcomes or self-reported communication in basic research. We discuss recommendations for future research, including regular use of behavioral observation methods with diverse samples, to triangulate across multiple methodologies and identify correspondence between behavioral and self-report measures.

Parent-child communication and adolescent sexual decision making: An application of family communication patterns theory

Family communication patterns theory proposes two dimensions of family communication-conversation orientation and conformity orientation-that can impact adolescent decision making. The purpose of this study is to examine how family communication patterns, above and beyond the frequency of parent-child sexual communication, are associated with adolescents' (a) sexual self-efficacy, (b) intentions to communicate about sex with partners, and (c) intentions to use condoms. Participants were 452 U.S. adolescents (M_age = 15.06; 59% girls; 35% White, 33% Latinx, 25% Black). Controlling for the frequency of parent-child sexual communication and gender, we found the interaction between conversation and conformity orientation was associated with adolescent sexual self-efficacy and intentions to communicate about sex with partners. When families were high on conversation and low on conformity, adolescents had statistically significantly higher sexual self-efficacy than any other family communication patterns. When families were low on conversation and low on conformity, adolescents had statistically significantly lower intentions to communicate with future sex partners than any other family communication pattern. Findings highlight the importance of understanding general communication processes beyond the frequency of parent-child sexual communication. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Development and Testing of the Parent-Child Sex Communication Inventory: A Multidimensional Assessment Tool for Parent and Adolescent Informants

Parent-child sex communication is a complex and multidimensional construct, and effective measurement tools that reflect this complexity are scarce. The purpose of this study was to develop and test an assessment tool of parent-child sex communication that reflects the multidimensional nature of the construct and which can be flexibly administered between both parent and adolescent informants. Using two large national samples from the United States involving adolescents (N = 2,044; M_age = 16.19, SD = 1.71) and unrelated parents of adolescents (N = 2,081), we psychometrically tested the Parent-Child Sex Communication Inventory (PCSCI). Validity evidence (i.e., construct, discriminant, convergent, and divergent) supported a 30-item measure that consisted of three overarching dimensions distributed along seven subscales: Frequency of sex communication (about sexual risk, about sex physiology, and about the positive aspects of sex); the Quality of sex communication (open communication versus parent controlled communication); and Child Managed sex communication (involving disclosure and secrecy). The PCSCI is an assessment tool for tapping multiple fundamental dimensions of parent-child sex communication that is quick and easy to administer. Further, it can be administered to both parent and adolescent informants. Therefore, it represents a significant methodological advancement for continuing research on parent-child sex communication.

Suicide Risk in Emerging Adulthood: Associations with Screen Time over 10 years

Suicide rates have increased over the past decade, and screen media (and social media in particular) are often blamed for this marked increase. However, there is little longitudinal research on this topic. The current study examined the link between various types of screen media use over a 10-year period (from adolescence to emerging adulthood) to suicide risk in emerging adulthood. Participants included 500 adolescents (51% female) who were first surveyed in 2009, when they were an average of 13.82 years old (range 12-15 years). For girls, a high level of social media or television use in early adolescence followed by a marked increase over time was most predictive of suicide risk in emerging adulthood. Additionally, video game use that increased over time was also associated with a higher risk for developing suicide risk for girls. A passive sensing measurement was also included at the final wave of data collection to obtain a more accurate and complete picture of phone use in particular. The use of entertainment apps was risky for girls while reading apps were risky for boys. Additionally, video game use (for boys) was associated with suicide risk when cyberbullying was also high. Identifying nonnormative patterns of media during adolescence may be instructive in terms of suicide prevention efforts.

Trajectories of Perceived Parental Psychological Control across Adolescence and Implications for the Development of Depressive and Anxiety Symptoms

Theory and research indicate considerable changes in parental control across adolescence (e.g., declining behavioral control), but the developmental course and significance of psychological control remains largely unknown. This study examined trajectories of adolescents' reports of mothers' and fathers' psychological control from ages 12 to 19, predictors of occupying distinct trajectories, and the developmental significance of these trajectories for adolescents' development of depressive and anxiety symptoms. It used eight waves of survey data on 500 adolescents (M_age = 11.83, SD = 1.03; 52% female; 67% White, 12% African American) and their parents from the Pacific Northwest United States. Most adolescents (about 90%) reported low but increasing levels of parental psychological control over time, with a small but significant subset (about 10%) perceiving perpetually elevated levels. Mothers' (but not fathers') depressive symptoms, reported at the age 12 assessment, predicted adolescents' membership in the elevated psychological control trajectory. Adolescents occupying these elevated trajectories showed more problematic growth in depressive and anxiety symptoms across adolescence. Taken together, the findings suggest that many adolescents experience increased parental psychological control as they age, and that variability in these trends indicates individual differences in their development of depressive and anxiety symptoms over time.

The socialization of attitudes about sex and their role in adolescent pornography use

INTRODUCTION

This study examines the socialization of conservative attitudes about sex and pornography use in later adolescence. We tested a socialization model whereby we anticipated that parent conservative sex attitudes would more strongly predict teen conservative sex attitudes when more frequent and higher quality parent-teen communication was present. We further hypothesized that teen conservative sex attitudes would mediate relations between parent conservative sex attitudes and teen pornography use over time.

METHODS

The data come from three waves of the National Survey of Youth and Religion (N = 3290; ages 13 through 18; M age = 15.5).

RESULTS

Path analyses found that teen sex attitudes mediated the negative link between parent sex attitudes and subsequent teen pornography use, but frequency and quality of parent-teen communication extensiveness (operationalized as frequency) and quality (operationalized as comfort) did not moderate the association between parent and teen sex attitudes. However, communication extensiveness did moderate relations between parent sex attitudes and later teen pornography use. The model was largely consistent across teen gender.

CONCLUSIONS

In short, parent and teen conservative sex attitudes are developmentally linked and predictive of later teen pornography use, but the role of parent-teen communication and teen gender are complex and in need of further research.

Serological survey of virus infection among wild house mice (Mus domesticus) in the UK

The serological prevalence of 13 murine viruses was surveyed among 103 wild-caught and 51 captive-bred house mice ( Mus domesticus), originating from several trapping locations in northwest England, using blood samples obtained during routine health screening of an established wild mouse colony. A high proportion of recently caught wild mice were seropositive for mouse hepatitis virus (86%), mouse cytomegalovirus (79%), mouse thymic virus (78%), mouse adenovirus (68%), mouse parvovirus (59%) and minute virus of mice (41%). Seroprevalences of lymphocytic choriomeningitis virus (LCMV), orthopoxvirus, reovirus-3 and murid herpesvirus 4 (MuHV-4, also called murine γ-herpesvirus [MHV-68]) were low (3–13%), and no animals were seropositive to Sendai virus, pneumonia virus or polyomavirus. Seroprevalence in wild-caught animals that had been in captivity for over six months was generally consistent with the range found in recently caught wild animals, while seroprevalence was generally much lower in captive-bred mice despite no attempt to prevent viral spread. A notable exception to this was LCMV, which appeared to have spread efficiently through the captive population (both captive-bred and wild-caught animals). Given the known viral life cycles in laboratory mice, it appears that viral persistence in the host was an important contributing factor in the spread of infection in captivity.

Why do male ICR(CD-1) mice perform bar-related (stereotypic) behaviour?

Prolonged interaction with cage bars by captive mammals (usually classed as stereotypic) may reflect poor welfare. Such behaviour may arise from motivation to investigate the external environment or to escape captivity. However, these hypotheses have not been explicitly tested. We raised mice, Mus musculus, to adulthood in modified laboratory cages with two sets of bars at the top and side of the cage. One set provided a potential escape route, and half of each set was backed by Perspex to reduce cues from the external environment. We predicted where mice should interact with the bars according to their motivational priorities. Body weights were recorded weekly to study the relationship between physical development and bar-related behaviour. Serum corticosterone was measured to monitor the effect of bar-related behaviour on stress physiology. Mice preferred to interact with bars where external cues were detectable. As adults, mice responded more to the bars providing a potential exit, though this was affected by the exit location. Corticosterone titres were higher in mice whose potential exit was situated at the cage top. Response to the bars was apparently restricted by the physical development of mice, particularly among those whose potential exit was situated in the cage top.

The scent of senescence: sexual signalling and female preference in house mice

Sexual signals are expected to be costly to produce and maintain, thus ensuring that only males in good condition can sustain their expression at high levels. When males reach senescence they lose physiological function and condition, which could constrain their ability to invest in costly sexual signals, decreasing their attractiveness to mates. Furthermore, females may have evolved mating preferences that cause avoidance of senesced males to enhance fertilization success and viability of offspring. Among mammals, the size of antlers and other weapons can decrease with senescence, but changes in olfactory sexual signals have been largely unexplored. We examined changes in olfactory signals with senescence in house mice (Mus musculus domesticus), where males excrete volatile and involatile molecules in scent marks that elicit behavioural and priming responses in females. Compared to middle-aged males, the urine of senesced males contained a lower concentration of involatile signalling proteins (major urinary proteins or MUPs), and associated volatiles that bind to these proteins. The reduced intensity of male scent will affect the longevity of scent signals deposited in the environment and, accordingly, females were less attracted to urine from senesced males deposited 12 h previously. Females also discriminated against senesced males encountered behind a mesh barrier. These results reveal that investment in olfactory signalling is reduced during senescence and suggest that senesced males and their scent may be less attractive to females.

How effective is recognition of siblings on the basis of genotype?

The ability to recognize kin based on genetic markers has been widely proposed as a mechanism to facilitate altruistic behaviour and inbreeding avoidance. Siblings are an important group of relatives to discriminate from unrelated individuals but present a problem, because siblings can share 0, 1 or 2 alleles at any single recognition locus. Here, we present a Bayesian model of kin recognition that defines the potential for genotypic information to convey kinship. Under the direct comparison model, where the signaller's genotype is compared with that of the receiver, the odds ratio that a pair of individuals were siblings was substantially increased if they shared both alleles at a single locus, but only a minority of siblings were recognized; increasing the number of recognition loci used could not increase both the odds ratio and the proportion of siblings recognized. A maternal comparison model, where the signaller's genotype is compared with that of the receiver's mother, performed poorly when only a single recognition locus was considered, but became increasingly effective with more recognition loci. Nevertheless, incorporating partial-matching information across multiple, independent loci are likely to be difficult. Further empirical work needs to establish the mechanistic basis of genetic kin recognition used by different taxa.

Haemoparasites of common shrews (Sorex araneus) in Northwest England

The presence of haemoparasites belonging to the taxa Anaplasma, Bartonella and Trypanosoma was determined among 76 common shrews (Sorex araneus) from Northwest England. Anaplasma phagocytophilum DNA was recovered from the blood of 1 shrew (1.3%), with the amplified 16S rRNA sequence identical to one previously reported from a bank vole (Clethrionomys glareolus). Trypanosoma spp. DNA was detected in 9 shrews (11.8%), the amplified 18S rDNA fragments being indistinguishable from one another, and distinct from previously published data. This represents the first report of trypanosome infection in S. araneus and suggests they are susceptible to an uncharacterized Trypanosoma species. Blood from 11 shrews (14.5%) yielded Bartonella spp., with characterization of isolates using comparative sequence analysis of partial gltA and 16S-23S rRNA intergenic spacer regions revealing 2 different genotypes. Phylogenetic inference from alignment of partial gltA sequences found that both UK S. araneus types formed a well-supported cluster with Bartonella sp. isolated from S. araneus in Sweden. No significant effect of host age, sex, or year of collection was found on prevalence of Bartonella or trypanosome infections. The results of this survey demonstrate that common shrews in the UK are susceptible to haemoparasitic infections, at prevalences similar to those reported from sympatric rodents.

The ownership signature in mouse scent marks is involatile

Male house mice advertise their territory ownership through urinary scent marks and use individual-specific patterns of major urinary proteins (MUPs) to discriminate between their own scent and that of other males. It is not clear whether recognition occurs through discrimination of the non-volatile proteins or protein-ligand complexes (direct model), or by the detection of volatile ligands that are released from MUPs (indirect model). To examine the mechanism underlying individual scent mark signatures, we compared investigatory and countermarking responses of male laboratory mice presented with male scent marks from a strain with a different MUP pattern, when they could contact the scent or when contact was prevented by a porous nitrocellulose sheet to which proteins bind. Mice investigated scent marks from other males whether these were covered or not, and biochemical analysis confirmed that the porous cover did not prevent the release of volatiles from scent marks. Having gained information through investigation, mice increased their own scent marking only if they had direct contact with another male's urine, failing to do this when contact was prevented. Individual signatures in scent marks thus appear to be carried by non-volatile proteins or by non-volatile protein-ligand complexes, rather than by volatiles emanating from the scent.

Multiple roles of major urinary proteins in the house mouse, Mus domesticus

The urine of the house mouse, Mus domesticus, contains large amounts of proteins that are specifically synthesized in the liver to be secreted in the urine. These proteins, termed major urinary proteins (MUPs), have multiple roles in the communication of information in urine-derived scent marks. They bind low-molecular-mass volatile pheromones, and effect their delivery to the scent mark, followed by a slow release that is controlled by the rate of dissociation from the MUPs. However, this family of proteins is extremely polymorphic, more than might be expected for a simple role of ligand binding and release. We have analysed the polymorphism in wild mice, and have now shown that the pattern of MUPs in the urine acts as a type of individuality 'bar code' that signals the identity of the owner of the scent mark. This multiplicity of function, from a generic ligand-binding property to an extremely specific individuality, sets the MUPs apart from other lipocalin family proteins that are involved in chemical signalling.

Individual recognition in mice mediated by major urinary proteins

The ability to recognize individuals is essential to many aspects of social behaviour, such as the maintenance of stable social groups, parent-offspring or mate recognition, inbreeding avoidance and the modulation of competitive relationships. Odours are a primary mediator of individuality signals among many mammals. One source of odour complexity in rodents, and possibly in humans, resides in the highly polymorphic major histocompatibility complex (MHC). The olfactory acuity of mice and rats allows them to distinguish between the urinary odours of congenic strains differing only in single genes within the MHC, although the chemical mediators or odorants are unknown. However, rodent urine also contains a class of proteins, termed major urinary proteins (MUPs), that bind and release small volatile pheromones. We have shown that the combinatorial diversity of expression of MUPs among wild mice might be as great as for MHC, and at protein concentrations a million times higher. Here we show in wild house mice (Mus domesticus) that urinary MUPs play an important role in the individual recognition mechanism.

Effect of polymorphisms on ligand binding by mouse major urinary proteins

Mouse urine contains an abundance of major urinary proteins, lipocalins, whose roles include slow release of semiochemicals. These proteins are highly polymorphic, with small sequence differences between individual members. In this study, we purified to homogeneity four of these proteins from two strains of inbred mice and characterized them by mass spectrometry. This analysis has led to the discovery of another variant in this group of proteins. Three of the polymorphic variants that map to the surface have no effect on the binding of a fluorescent probe in the binding cavity, but the fourth, characterized by a Phe to Val substitution in the cavity, shows a substantially lower affinity and fluorescence yield for the probe. These results are interpreted in light of the known crystal structure of the protein and molecular modeling calculations, which rationalize the experimental findings. This work raises the possibility that the calyx-binding site can show specificity for different ligands, the implications of which on pheromone binding and chemical communication are discussed.

Structural complexity of territories: preference, use of space and defence in commensal house mice, Mus domesticus

Previous studies suggest the physical structure of a habitat has profound effects on intraspecific competition and spacing behaviour among small mammals. We compared habitat preferences and the exploratory behaviour and aggressive territorial defence of male house mice in three types of enclosure differing only in their degree of structural complexity. Each enclosure contained a nestbox placed in one corner, a central food hopper and 10 house bricks. The bricks were either placed around the outer walls (open enclosures), lined up across the middle (wall enclosures) or scattered separately across the floor (complex enclosures). In pairwise choice tests, mice showed a strong preference for wall or complex enclosures over open enclosures but no preference between wall and complex enclosures. They were more active throughout the enclosure with complex structuring and stayed near the side walls in open enclosures. Residents in open enclosures initially showed a lower rate of attack and duration of pursuit when faced with an intruder but not when faced with a second intruder. In complex enclosures, nearly all encounters ended because the residents continued pursuit but lost track of the intruder. This occurred in only half of intruder pursuits in open and wall enclosures. Our results suggest that mice prefer areas containing physical structure because this provides a degree of protection from predators but territories with complex physical structuring appear to be much more difficult to defend. Complex areas may thus support a higher density of mice than open areas or those with more simply aligned physical structuring. Copyright 2000 The Association for the Study of Animal Behaviour.

The consequences of inbreeding for recognizing competitors

Extreme inbreeding will compromise an animal's ability to discriminate between individuals and, thus, assess familiarity and kinship with conspecifics. In rodents, a large component of individual recognition is mediated through chemical communication. The counter-marking of competitor males' scent marks provides a measure of discrimination between their own scent and that from other individuals. We investigated whether males in common outbred (ICR(CD-1) and TO) and inbred (BALB/c) strains of laboratory mice could recognize the urinary scents of other individuals by measuring their investigation and counter-marking responses. Dominant males of outbred strains investigated and counter-marked scents from other males, whether of the same or another strain. Dominant inbred BALB/c males investigated but did not counter-mark their own strain scents, counter-marking only those from another strain. They did not use environmentally induced status differences in odours to recognize scents from other males. The inability of the inbred mice to discriminate between their own scent marks and those of other males is likely to alter their competitive behaviour, which could influence responses in experiments and the welfare of caged laboratory mice.

Unravelling the chemical basis of competitive scent marking in house mice

Major urinary proteins (MUPs) in the urine of male house mice, Mus domesticus, bind the male signalling volatiles 2- sec -butyl-4,5-dihydrothiazole (thiazole) and 3,4-dehydro- exo -brevicomin (brevicomin) and slowly release these volatiles from urinary scent marks. To examine the role of urinary proteins and volatiles, either attached or unattached to the proteins, in competitive scent marking, we fractionated urine from isolated male BALB/c laboratory mice, Mus musculus, by size-exclusion chromatography into three pools. Pool I contained all of the urinary proteins and their bound ligands while pools II and III contained lower molecular weight components including unbound signalling volatiles. In experiment 1, pools I-III were streaked out on to absorbent paper (Benchkote) and introduced into enclosures housing single wild-caught male mice, together with a clean control surface. Each male was tested with fresh stimuli and with aged stimuli deposited 24 h previously. Only pool I stimulated significantly more countermarking and investigation than the control, attracting mice to investigate from a distance even when the rate of ligand release was considerably reduced after 24 h. Experiment 2 examined responses to pool I when this was fresh, aged by 7 days, or had been mixed with menadione to displace ligands from the proteins. Although all three protein stimuli were investigated and countermarked more than a clean control, the aged and menadione-treated pool I stimulated the strongest responses, despite containing the lowest levels of thiazole and brevicomin. Thus competitive countermarking is stimulated by proteins or by nonvolatile protein-ligand complexes in male urine, while release of volatile ligands attracts attention to a competitor's scent marks. Copyright 1999 The Association for the Study of Animal Behaviour.

The competing countermarks hypothesis: reliable assessment of competitive ability by potential mates

Scent marking on top of (overmarking), or in the vicinity of, a scent mark already present is commonly termed countermarking. Scent marks and countermarks provide a continuous record of competitive challenges between conspecifics, thus providing a reliable advertisement of an individual's ability to dominate or defend an area to other competitors and potential mates. To test the hypothesis that females should prefer males that countermark competing scent marks in their territory over those whose own marks are partially countermarked by a competing male, we manipulated scent marks in the territories of neighbouring male house mice (captive-bred Mus domesticus). As predicted, oestrous females were more strongly attracted to approach territory owners that countermarked the scent mark challenges of competitors than those that had been countermarked, and females themselves deposited more scent marks near the scents of these males. To investigate whether female mice use scent age, overlap or intrinsic qualitative or quantitative differences between scent marks and countermarks to make this discrimination, we redeposited male scent marks artificially as marks and partially overlapping countermarks, with or without a 24-h age difference between them. While the intrinsic quality or quantity of countermarks did not affect discrimination, an age difference between the original mark and subsequent countermark was important for consistent discrimination. The ultimate function of such competitive scent signalling thus may be to provide potential mates with a reliable indicator of the competitive ability of individuals advertising their high status. Since scent marks remain in the environment and are continuously available to challenge and investigation, they may provide a particularly effective and reliable means of dominance advertisement. Copyright 1999 The Association for the Study of Animal Behaviour.

Housing and welfare in laboratory rats: effects of cage stocking density and behavioural predictors of welfare

Using male and female Alderley Park (Wistar-derived) rats housed in single-sex groups in standard laboratory cages, we looked at the effect of group size (one, three, five or eight) on competitive behaviour and time budgeting (initial and longer term), changes in their serum testosterone (males), corticosterone and antibody concentrations, and organ pathology at age 16 weeks, together with the interrelationships between behavioural measures and pathophysiological indices of social stress. Group size had only limited long-term effects on overall time budgeting and did not affect pathophysiological responses, although there were highly significant differences between individuals in replicate cage groups. Pathophysiology within both sexes showed strong and highly specific correlations with a small subset of behaviours suggesting frustrated attempts to escape from cages, including chewing the cage bars. Escape-related behaviour also correlated strongly with one component of competitive behaviour, Aggressive Grooming within both sexes, although Aggressive Grooming correlated with pathophysiological responses only among males. Females generally showed greater escape-related behaviour associated with greater signs of pathophysiology regardless of the level of aggression shown between cagemates. Major differences in intercorrelated behavioural and pathophysiological responses between replicate groups implied that the individual composition of groups rather than their size had the greater impact on the welfare of the rats, especially among females. This may be consistent with adaptive sex differences in their competitive reproductive strategies. The frequency of apparent escape-related behaviours and Aggressive Grooming, particularly when rats are first introduced into their cage groups, may provide a simple assessment of the welfare implications of particular cage groupings. Copyright 1999 The Association for the Study of Animal Behaviour.

Competitive behaviour in an island population of house mice, Mus domesticus

Because of the cryptic nature of small mammals inhabiting vegetation with widely scattered food resources, little is known about the behavioural mechanisms underlying their spatial dispersion. While house mice exploiting human-built environments attempt to exclude intruders aggressively from small territories that contain concentrated food resources, comparative tests show that the grassland mouse, M. spretus, establishes dominance relationships and then avoids sites used by dominant competitors, probably to avoid displacement from sites that provide safety from predators. We carried out further comparative tests to examine competitive behaviour and response to odours from same-sex conspecifics among house mice living ferally on the Isle of May, U.K., using recently captured adult males (N=62) and females (N=23). In contrast both to house mice caught from buildings and to the grassland M. spretus, feral house mice from the Isle of May showed no aggressive, defensive or cautious behaviour on meeting a same-sex conspecific, with the exception of one aggressive male. Scent marks had no effect on their response to a competitor, although intruders in a scent-marked arena showed a significant sex difference in choice between a clean nest site versus one soiled by a same-sex resident: males spent more time in the soiled nest while females spent more time in the clean one. We propose that the lack of aggression among feral May mice may be due to the infeasibility of defending large territories, containing scattered resources, on an island where there is no real predation risk. We suggest that this hypothesis may explain the lower aggression and higher densities that are characteristic of populations of small mammals, reptiles and birds living on small islands. Copyright 1998 The Association for the Study of Animal Behaviour.

Simultaneous coronary artery bypass grafting and abdominal aneurysm repair decreases stay and costs

BACKGROUND

Patients with large (> or = 5.0 cm) abdominal aortic aneurysms (AAA) frequently have marked associated coronary artery disease. We hypothesized that a single operation for coronary artery bypass grafting (CABG)/AAA would provide equivalent, if not improved, patient care while decreasing postoperative length of stay and hospital costs compared with staged procedures.

METHODS

Eleven patients to date have undergone a combined procedure at our institution. Ten underwent CABG followed by AAA repair, whereas one patient received an aortic valve replacement before aneurysm repair. We performed a retrospective analysis comparing the postoperative length of stay and hospital costs for this single procedure to a combined cohort of 20 randomly selected patients who either received AAA repair (n = 10) or standard CABG (n = 10) during the same time period.

RESULTS

No operative mortality has been reported. There were no episodes of neurologic deficit or cardiac complication after these procedures. The postoperative length of stay was significantly decreased for the CABG/AAA group compared with the combined postoperative length of stay for the AAA plus CABG group (7.44+/-0.88 days versus 14.10+/-2.00; p = 0.012). Total hospital costs were also significantly decreased for the CABG/AAA group compared with total hospital costs for the AAA plus CABG group ($22,941+/-$1,933 versus $34,076+/-$2,534; p = 0.003).

CONCLUSIONS

A single operation for coronary revascularization and AAA repair is safe and effective. Simultaneous CABG and AAA repair substantially decreases postoperative length of stay and hospital costs while avoiding possible interim aneurysm rupture and repeat anesthesia.

Scent marks as reliable signals of the competitive ability of mates

The quality of an individual's odour can allow potential mates to discriminate against individuals of low social class, poor health status or unsuitable genotype. Competitive scent marking provides a further mechanism which could allow mates to discriminate between individuals of apparently high quality. The presence or absence of fresh countermarks from competitors within an owner's territory or area marked by a dominant animal provides a reliable indicator of the owner's ability to defend its territory or dominate competitors. This could be used by potential mates to discriminate between individuals advertising their apparently high competitive ability through their scent-marking behaviour and odour quality. We tested this by manipulating scent marks in the neighbouring territories of wild-caught male house mice, Mus domesticus. As predicted, oestrous females used scent marks to select males apparently able to defend exclusive territories over those unable to exclude intruders. Females were more strongly attracted to the odour of owners of exclusively marked territories and showed more sexually related behaviour when interacting with these males. Furthermore, while females preferred a territory containing a better protected nest site regardless of the owner's apparent competitive ability, they still used the presence or absence of intruder countermarks when selecting a potential mate. This suggests that females use scent marks as a reliable signal of the best-quality mate among neighbouring males independently of their nest location. Since assessment depends on both the territory holder's own marks and those of competitor males, countermarking is likely to be an important mechanism of competition for mates between neighbours. Copyright 1998 The Association for the Study of Animal Behaviour

Proteins in urine scent marks of male house mice extend the longevity of olfactory signals

The binding of volatile semiochemicals to lipocalin proteins in many mammalian scent marks may provide a gradual release of volatile ligands, extending the life of airborne odour signals. We tested this by using menadione to displace semiochemical ligands from major urinary proteins (MUPs) in urine streaks obtained from adult male house mice, Mus domesticus, and assessed the responses of other males to these and to intact urine marks as they aged. Dominant male mice scent-mark their territories extensively with urine streaks; MUPs in these marks bind at least two semiochemically active molecules, 2-sec-butyl-4,5-dihydrothiazole (thiazole) and 2,3-dehydro-exo-brevicomin (brevicomin), associated with the males' aggressive status. Wild-caught males (N=24), housed in individual enclosures, were presented with two glass slides, behind mesh to prevent contact, on which 10 µl of both unfamiliar urine and 0.5 mg/ml menadione in ethanol had been streaked. On one slide the urine and menadione solution were mixed to displace ligands; on the other they were separate (intact urine). We carried out tests 0, 0.5, 1 or 24 h after deposition, and matched them to changes in the concentration of thiazole and brevicomin within the intact and displaced marks. Males were hesitant to approach intact urine up to 1 h old but, when ligands were displaced, or were reduced to low levels by natural evaporation from intact urine streaks aged 24 h, their approach was similar to that to water and to menadione controls. Ligands did not appear to cause any longer term avoidance and, after the first approach, investigation increased with the freshness of urine regardless of when the ligands were displaced. This is the first direct demonstration that proteins evince a slow release of olfactory signals from mammalian scent marks. The nature of their response suggests that, from a distance, mice may be unable to tell whether airborne signals emanate from scent marks or from the donor himself and we suggest that this may provide territory owners with a major advantage in defending their territories.Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Tamoxifen-induced regression of breast cysts

The use of Tamoxifen as treatment for breast cancer is well established and its use experimentally as prophylaxis is promising, but little has been written about mammographically detected changes in breast parenchyma as a result of Tamoxifen therapy. We report two cases of spontaneous regression of breast cysts after Tamoxifen therapy for premenopausal breast cancer in the contralateral breast.

Social interaction alters attraction to competitor's odour in the mouse Mus spretus Lataste

When animals defend territories that are large and structurally complex, scent marks alone are unlikely to be reliable signals of a resident's dominance and competitors should require initial proof through direct interaction. This was tested using freshly captured Mus spretus which occupy large non-overlapping ranges in grassland but are strongly attracted to substrate odours from unfamiliar competitors. Choice tests measured time spent investigating and chewing to gain access to paired nestboxes when the entrances were blocked with mesh. Experiment 1 established that mice of both sexes were more strongly attracted to their own odour than to a clean site. Experiment 2 examined choice between the subject's own odour and that of an unfamiliar same-sex competitor both before and after meeting the competitor in a neutral (clean) arena. Prior to interaction, males exerted much effort to gain access to both their own and their unfamiliar competitor's odour. Once relative dominance had been established through agonistic interaction, subordinates avoided their dominant competitor's odour in favour of their own while dominants continued to be attracted to both. There was little aggressive competition between unfamiliar females and relative status did not affect their attraction to a competitor's odour. Females tended to be more attracted to a competitor's odour than to their own prior to interaction but showed less attraction to a competitor's odour post-interaction. A third experiment showed that the odour of an unfamiliar male was more attractive than that from an unfamiliar female, especially to males. The consequences of these responses for maintaining spatial dispersion in this species are discussed.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Minimally invasive coronary artery bypass grafting decreases hospital stay and cost

OBJECTIVE

The authors performed a retrospective cost analysis for patients undergoing revascularization of their left anterior descending (LAD) coronary artery either by standard coronary artery bypass grafting (CABG), percutaneous transluminal coronary angioplasty (PTCA), or minimally invasive coronary artery bypass grafting (MICABG).

SUMMARY BACKGROUND DATA

Minimally invasive CABG has become a safe and effective alternative treatment for single-vessel coronary artery disease. However, the acceptance of this procedure as a routine alternative for the treatment of coronary artery disease will depend on both long-term graft patency rates as well as a competitive market cost.

METHODS

The authors conducted a retrospective analysis of three patient groups undergoing LAD coronary revascularization from January 1995 to July 1996. Ten patients were selected randomly from this period after PTCA of an LAD lesion with or without stenting. Nine patients underwent standard CABG on cardiopulmonary bypass with a left internal mammary artery. Nine patients received MICABG via a limited left anterior thoracotomy and left internal mammary artery to LAD grafting without the use of cardiopulmonary bypass.

RESULTS

Percutaneous transluminal coronary angioplasty (n = 10) was unsuccessful in two patients. One patient in the MICABG group (n = 9) was converted successfully to conventional CABG because of an intramyocardial LAD and dilated left ventricle. There was no operative morbidity or mortality in any group. Average length of stay postprocedure was decreased significantly for both the MICABG and PTCA groups when compared with that of conventional CABG (n = 9) (2.7 + 0.26, p = 0.009, and 2.6 + 0.54, p = 0.006, vs. 4.8 + 0.46, respectively). Total hospital costs for the MICABG and PTCA groups were significantly less when compared with those of standard CABG ($10,129 + 1104, p = 0.0028, and $9113 + 3,039, p = 0.0001, vs. $17,816 + 1043, respectively). There were no statistically significant differences between the MICABG and PTCA groups.

CONCLUSIONS

The final role of minimally invasive CABG is unclear. This procedure is clearly cost effective when compared with that of PTCA and conventional CABG. The long-term patency rates for MICABG will determine its overall efficacy.

Expanding aneurysm of aberrant right subclavian artery. Case report and imaging evaluation

We present a case illustrating the complementary role of CT and angiography in evaluation of a slowly expanding vascular thoracic mass representing aneurysmal enlargement in an aberrant right subclavian artery. Anatomy, embryology, incidence, and imaging of aberrant right subclavian artery, bicarotid trunk, and aneurysmal dilatation of the diverticulum of Kommerell are reviewed.

Molecular heterogeneity of urinary proteins in wild house mouse populations

Major urinary proteins (MUPs) from the urine of individual wild mice were characterized using electrospray ionization mass spectrometry (ESI-MS) and compared to MUPs from the urine of inbred mice. The wild mice showed considerable variation between individuals in the expression of a group of MUPs with similar masses. Some individuals excreted MUPs of unique molecular mass whilst some failed to express MUPs seen commonly in the other individuals. All the wild individuals contained proteins not previously observed in inbred mice. Urine from one individual was fractionated using anion exchange chromatography prior to analysis by ESI-MS. By analysing urine from inbred samples under the same conditions it was possible to relate, using mass and net charge in solution, MUPs from the wild sample to the MUPs that have been observed previously in inbred strains. This has allowed tentative identification of some MUPs from the wild mouse. The effect of collection history of urine from wild mice was also investigated. ESI-MS analysis of MUPs in a faecally contaminated sample showed the loss of a C-terminal tripeptide when compared to an uncontaminated sample from the same mouse, consistent with the presence of a specific endopeptidase. Similarly a sample of pooled urine provided by twelve individuals trapped from the same population showed evidence of loss of the C-terminal dipeptide.

The prevalence and intensity of infection with helminth parasites in Mus spretus from the Setubal Peninsula of Portugal

The results of a 5 year study of helminth parasites of Mus spretus, are reported. Six nematode and 5 cestode species were identified but no helminth showed 100% prevalence in M. spretus, the most commonly encountered nematode and cestode species being Syphacia obvelata (46.6%) and Taenia taeniaeformis (22.4%). Among the more unusual helminth species identified was Eucoleus bacillatus, a capillariid nematode inhabiting the stomach musculature. This species was identified in 3 of the 5 years of the study. The results are discussed in the broader context of previous studies and the epidemiology of rodent helminth infections in general.

Of mice and kin: the functional significance of kin bias in social behaviour

1. Sharing recent ancestry (kinship) increases the degree of genetic similarity between individuals, where genetic similarity could mean anything from sharing a particular allele to sharing an entire genome. 2. Genetic similarity can influence behavioural and other responses between individuals in a number of ways, discriminatory and non-discriminatory. All are likely to result in kin bias, because of the correlation between genetic similarity and kinship, but only some should be regarded as involving kin discrimination. 3. Non-discriminatory kin bias could arise through close relatives sharing, for instance, physical characteristics (such as those influencing competitive ability), thresholds of behavioural response or requirements for particular resources. 4. Discriminatory kin bias could arise through the direct perception of genetic similarity between individuals (direct similarity discrimination) or the use of cues likely to correlate with genetic similarity (indirect similarity discrimination--of which kin discrimination is one form). Alternatively, it could arise incidentally through mistaken identity or discrimination at some other level, such as species identification. 5. Experiments with laboratory and wild house mice have revealed kin bias in a number of contexts, including (a) parental and infanticidal behaviour, (b) sexual development and behaviour and (c) investigatory behaviour and passive body contact among juveniles and adults. 6. While kin bias in mice has been interpreted as evidence for kin discrimination, there are several problems with such an interpretation. These include (a) pronounced and complex effects of familiarity on discrimination, (b) a high risk of error-proneness in the indirect cues used in apparent kin discrimination and (c) weak and easily disrupted kin bias effects in certain contexts. 7. Consideration of social structure and discriminatory responses within populations of wild house mice leads to an alternative explanation for some kin bias in terms of incidental discrimination based on social group membership. 8. Several results from laboratory experiments suggest incidental discrimination is a more parsimonious explanation than kin discrimination for some intrasexual kin bias in behaviour. However, kin or direct similarity discrimination appears to be the most likely explanation for other aspects of intrasexual kin bias and for intersexual kin bias.

The effect of temperature on the growth ofCandida saké isolated from the leaves of a subantarctic grass

During a survey of microfungi on the subantarctic island of South Georgia, large numbers of phylloplane yeasts were isolated in late spring from leaves of a tussock grass. The dominant yeast was identified asCandida saké, this being the first record for the Antarctic region. Isolates in liquid culture had a temperature optimum for growth of 20-25°C. It was capable of assimilation of a range of simple carbohydrates, similar to those found in leachates from new leaves of the tussock grass. The seasonal decline of yeasts on the phylloplane is discussed in terms of the availability of leachate and the growth of filamentous microfungi on new leaves.