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PubMed1989

Central implants of diluted estradiol: independent effects on ingestive and reproductive behaviors of ovariectomized rats.

The present experiment was undertaken to evaluate the hypothesis that the effects of estrogens on feeding and sexual behaviors are organized separately within the brain. Thirty-three ovariectomized rats were implanted with bilateral guide cannulae aimed at either the paraventricular nucleus (PVN), medial preoptic area (MPOA), or posterior hypothalamus (PH). Subjects that received PVN implants were stimulated with either undiluted estradiol, a 3:1, or 10:1 mixture of cholesterol and estradiol. Animals in the other groups were treated with undiluted estradiol. All females were stimulated unilaterally with cholesterol and estradiol, yielding a total of 66 stimulation sites. Histological analysis revealed that, compared to cholesterol implants, undiluted estradiol in the PVN reduced food intake and body weight. More importantly, diluted estradiol implants in the PVN significantly lowered food intake and body weight. In contrast, undiluted estradiol in the MPOA, PH, or ventromedial hypothalamus (VMH) had no significant effects on feeding or body weight. Analyses of variance revealed significant main effects of implant location on female sexual behavior. Newman-Keuls tests indicated that diluted estradiol implants in the PVN produced lordosis quotients and quality scores that were significantly lower than those obtained with VMH implants. The possibility that the behavioral changes observed were due to peripheral rather than central effects of the hormone was evaluated by comparing the results of implants that produced vaginal cell cornification to those that did not. There were no significant differences between these groups on any of the other dependent variables, indicating that peripheral estradiol sufficient to induce vaginal cell cornification was neither necessary nor sufficient to account for the behavioral changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Effects of corticosterone treatment on male aggressive behavior in a lizard (Anolis sagrei).

Social dominance in several species of lizards appears related to adrenal gland activity. The purpose of this study was to test whether the adrenal hormone corticosterone (CS) would inhibit the aggressive behavior of males of the lizard Anolis sagrei. Reproductively active males were randomly assigned to either CS or placebo (P) treatment groups or to an untreated stimulus male group. Both CS and P were administered in pellet form. Corticosterone pellets were designed to release approximately 4.8 micrograms of CS/day. Initially (Day 1), treatment males were implanted subcutaneously with a single pellet of either CS or P. After 1 week (Day 8), behavior tests were staged between treatment males and untreated stimulus males. The behavior of treatment males in response to stimulus males was videotaped. Significantly fewer CS-treated males than P-treated males approached the stimulus males, erected a crest, or showed biting behavior. Corticosterone-treated males also displayed significantly less frequently than did P-treated males and gave fewer displays of a type associated with dominance. Mean combined testis weight at the end of the experiment was significantly less in CS-treated males than in P-treated males and spermatogenic activity in CS-treated males was reduced. Plasma testosterone in CS-treated males was nondetectable, whereas P-treated males had normal levels of this steroid. These results indicate that CS can inhibit male aggressive behavior and testicular function in a lizard and support the hypothesis that the behavior changes observed in subordinate animals following defeat in agonistic encounters may in part be due to increased plasma CS levels.

Aggression↗
PubMed1991

Daily variation of multiple behaviors in Aplysia fasciata: integration of feeding, reproduction, and locomotion.

Daily variations in feeding, reproductive behaviors, and activity level were examined under three conditions: (1) animals had access to food and mates; (2) there was access only to food; (3) neither food nor mates were present. Behaviors differed in amplitude of variations from their daily mean value. Egg-laying had the strongest tendency to be clustered. Amplitude of variations in courtship and swimming was larger than those of immobility, crawling, and feeding, while moving in place was the least clustered behavior. Changes in state affected the tendency to be clustered. When food and mates were present, amplitude of variations became progressively larger for immobility, moving in place, crawling, and swimming. Behaviors differed in the degree to which variations were patterned as a 1/day oscillation. Relatively little of the variability in crawling, moving in place, courtship, and egg-laying was due to a 1/day oscillation under any condition. By contrast, a large proportion of the variability of immobility, swimming, mating, and eating was modulated by a 1/day oscillation in at least one condition. The contribution of a 1/day oscillation to variability differed in the conditions examined. For immobility and swimming, when food and mates were present, the 1/day component of variability became smaller. By contrast, presence of mates led to an increase in the 1/day component of variability modulating feeding. Daily peaks of swimming and feeding were in phase with one another, and out of phase with mating and feeding. The ratio of locomotion to inactivity is constant, independent of change in external conditions. However, this ratio varied throughout the day. When food and mates were absent, variations of immobility and swimming were strongly related to variations in the inactivity ratio. When food and mates were added, this tendency decreased. The data suggest that daily variations in occurrence of behaviors can be accounted for by interactions between oscillators affecting Aplysia behavior and motivational variables. A 1/day oscillator has strong effects on mating, swimming, and immobility. The effect of the oscillator is modified by changes in motivational state.

Animals↗
PubMed1996

Behavioral changes induced by GABA-receptor agonists in Lymnaea stagnalis L.

1. GABA, the GABAA receptor agonist, muscimol, and the GABAB receptor agonist, baclofen, were tested to study the involvement of the GABA neurotransmitter system in control of behaviour in the freshwater pulmonate snail, Lymnaea stagnalis L. Single injections of GABA (1-10 micrograms/ gbw) into the haemocoel of intact snails elicits a sequence of behavioural changes subsequently affecting feeding, locomotion, escape reactions, male mating behaviour and respiration. 2. Both muscimol and baclofen mimic distinct aspects of GABA action implying that the GABA action is mediated by both types of receptors. 3. The modulatory actions of GABA, muscimol, and baclofen on feeding were manifested as opening of the mouth and triggering of specific radular movements (e.g., protraction, retraction, rasping). 4. Baclofen (1-10 micrograms/gbw) evoked the full erection of the penis for a time long enough for natural copulation, while GABA itself caused only partial eversion of the preputium. Muscimol was less effective than GABA. The latency to penis eversion varied in a dose-dependent manner. The data emphasize the participation of baclofen-sensitive receptors in control of reproduction. 5. GABA and baclofen induced withdrawal of the head and anterior part of the foot accompanied by arrest of locomotion and respiration could be considered to be an escape reaction. 6. Muscimol (1-5 micrograms/gbw) failed to elicit withdrawal reactions but caused the loss of normal orientation and longitudinal contractions of the foot. 7. All the agents tested inhibited locomotion in a dose-dependent manner, for a substantial period of time. A decrease in total locomotor activity lead to the failure of animals to attach to the underlying surface, to have foot contractions and also to diminish locomotor velocity. 8. The majority of animals maintained the stereotyped complex reactions of respiration, but with restricted clockwise turning of the shell after drug treatment. 9. All the substances were shown to shift the background behavioural state characterised by high BSSs to a state similar to "rest" which was awarded a low BSS. It is concluded that the GABA neurotransmitter system can play an important role in activation and coordination of neuronal ensembles underlying behaviour and behaviour selection in Lymnaea stagnalis L.

Animals↗
PubMed1991

Ectopic expression of sex peptide alters reproductive behavior of female D. melanogaster.

Sex peptide, a secreted component of the male accessory glands, has been shown to induce behavioral and physiological changes in mated Drosophila. We transformed flies with a hybrid gene containing an hsp70 promoter fused to a cDNA encoding sex peptide. Heat-induced ectopic expression of the peptide in transgenic virgin females altered their reproductive behavior, in the presence of courting males, to that observed in mated females. This demonstrates that the peptide is functional as expected. Time course studies revealed that the behavioral change appeared earlier than the stimulated ovulation. We have also introduced a modified sex peptide gene that is driven by the yp1 enhancer, conferring expression in adult females, and shown that these flies refuse mating constitutively in the presence of courting males and lay unfertilized eggs at the rate of mated females.

Animals↗
PubMed1992

Human immunodeficiency virus/acquired immunodeficiency syndrome in pregnant women.

A pregnant woman experiences selective immunosuppression as a physiologic response to the presence of a genetically heterologous fetus. Case reports early in the acquired immunodeficiency syndrome (AIDS) epidemic suggested that adverse human immunodeficiency virus (HIV)-related clinical outcomes might be causally associated with pregnancy. A review of relevant published data indicates that: (1) Adverse clinical outcomes of pregnancy are common among HIV-infected pregnant women, but no studies to date have fully disentangled the many confounding factors. (2) HIV-related complications are common in pregnancy only among immunosuppressed (< 300 CD4+ cells/mm3) women. (3) The distinct effect of pregnancy on the expression of HIV infection cannot be evaluated in the absence of appropriately controlled observations. (4) Cofactors for perinatal transmission are poorly understood. (5) Research into the motives for reproductive decisions and behaviors is of critical importance for improving our health education and outreach efforts for high-risk women. (6) Adequate clinical treatment and prophylactic health care services must be made easily accessible and available to women at high risk of HIV disease. (7) Treatment with available antiviral and anti-Pneumocystis drugs is advisable for HIV-infected pregnant women with fewer than 300 to 350 CD4+ cells/mm3, though data to definitively guide therapeutic decision making are not available. (8) Large multicenter studies are needed to recruit patients and to retain them in sufficient numbers, allowing for better evaluation of the many variables determining clinical outcomes for HIV-infected mothers and their infants. The natural history of HIV in pregnant women must be studied to facilitate clinical decision making, and to design and implement interventions, including prevention (behavior change, vaccines) and treatment (chemotherapy, immunotherapy).

Acquired Immunodeficiency Syndrome↗
PubMed1992

Changing patterns of adolescent sexual behavior: consequences for health and development.

Sexuality is a fundamental quality of human life, important for health, happiness, individual development, and indeed for the preservation of the human race. During the dynamic period of adolescence in which the passage from childhood to maturity takes place, sexuality takes on new dimensions; feelings become more intense, relationships become more complex, and the consequences of sexual behavior are radically altered. This not only affects the behavior of young people but also of those who interact with them, their families and peers, and those who work in the health, education, youth, social welfare, and other sectors. In the contemporary world the conditions of life for many young people have also changed, and with it patterns of sexual behavior. In general, earlier puberty, later marriage, a decline in the family leading to less control and more autonomy, and intense exposure to sexual stimuli via the mass media and travel across cultural boundaries have made pre-marital adolescent sexual activity more common. This has added to traditional problems of early marriage, newer problems of early pregnancy, childbirth, and induced abortion outside of marriage, sexually transmitted diseases, and human immunodeficiency syndrome infection leading to acquired immunodeficiency syndrome. But the work of the World Health Organization (WHO), along with many others in the field, strongly suggests that given appropriate information and services, trust and equity between the sexes, young people will behave responsibly and well. In this paper some of the findings from methods developed by WHO for research, training, advocacy, and evaluation, and findings in relation to patterns and determinants of sexual and reproductive health and development will be described, and future directions suggested.

Adolescent↗
PubMed1993

Contraceptive self-efficacy in college women.

We examined the relationship between the theory of self-efficacy and its effect on contraceptive use along with other variables in a predominantly white female college population. Written survey questionnaires were administered to 356 subjects in college classrooms; the study sample was limited to those 250 female subjects who were age 17-25 years unmarried, and sexually active. The questionnaire was designed to measure contraceptive use, contraceptive self-efficacy, demographic variables, and other variables associated with the college psychosocial environment (i.e., alcohol use, history of sexual assault, and future orientation in education and career plans). Contraceptive self-efficacy (CSE) was highly correlated with effective use (r = .4, p < 0.01). Highly effective contraceptive users had a significantly higher mean CSE score (p < 0.01) than that of less effective users. Logistic regression analysis of effective contraceptive use resulted in a four-factor model that correctly classified 76.3% of users. Contraceptive self-efficacy was the most important predictor of contraceptive use for this sample. Lack of barriers to contraception was also important, with knowledge and length of time of sexual activity also included in the final regression model. Most demographic and future orientation variables were not significantly associated with effective use; variables measuring sexual experience and personal attitudes and perceptions about birth control were more significantly associated with effective use. A lack of interference from alcohol was highly associated with effective contraceptive use. Self-efficacy would seem to be important in predicting contraceptive use and effecting behavior change.

Adolescent↗
PubMed1997

Using the Kalman filter and dynamic models to assess the changing HIV/AIDS epidemic.

Many factors, including therapy and behavioral changes, have modified the course of the HIV/AIDS epidemic in recent years. To include these modifications in HIV/AIDS models, in the absence of appropriate external data sources, changes over time in the parameters can be incorporated by a recursive estimation technique such as the Kalman filter. The Kalman filter accounts for stochastic fluctuations in both the model and the data and provides a means to assess any parameter modifications included in new observations. The Kalman filter approach was applied to a simple differential model to describe the observed HIV/AIDS epidemic in the homo/bisexual male community in Paris (France). This approach gave quantitative information on the time-evolution of some parameters of major epidemiological significance (average transmission rate, mean incubation rate, and basic reproduction rate), which appears quite consistent with the recent epidemiological literature.

Disease Outbreaks↗
PubMed1995

A Drosophila seminal fluid protein, Acp26Aa, stimulates egg laying in females for 1 day after mating.

Mating triggers behavioral and physiological changes in the Drosophila melanogaster female, including an elevation of egg laying. Seminal fluid molecules from the male accessory gland are responsible for initial behavioral changes, but persistence of these changes requires stored sperm. Using genetic analysis, we have identified a seminal fluid protein that is responsible for an initial elevation of egg laying. This molecule, Acp26Aa, has structural features of a prohormone and contains a region with amino acid similarity to the egg-laying hormone of Aplysia. Acp26Aa is transferred to the female during mating, where it undergoes processing. Here we report the generation and analysis of mutants, including a null, in Acp26Aa. Females mated to male flies that lack Acp26Aa lay fewer eggs than do mates of normal males. This effect is apparent only on the first day after mating. The null mutation has no other detectable physiological or behavioral effects on the male or the mated female.

Amino Acid Sequence↗
PubMed1990

Male knowledge of and attitudes and practices towards AIDS in Zimbabwe.

This paper presents findings from a survey on knowledge of and attitudes and practices towards AIDS among currently married Zimbabwean men conducted between April and June 1988. Findings indicated that knowledge was reasonably high: 89.7% reported having heard of AIDS. The young and middle-aged groups, the most educated, and the urban men were the most knowledgeable in identifying routes of transmission. However, 22% did not know that there could be asymptomatic carriers of the virus capable of transmitting the virus and infecting others. Furthermore, 38% did not know that all those affected with AIDS eventually die as a result, and only 55% knew that there is no cure for AIDS. Behavioral change in order to avoid contracting AIDS seems relatively low given this sample's history of sexually transmitted diseases and extramarital sexual relations during the year prior to the survey. Although condom use was the lowest percentage of the behavioral change categories, a high percentage reported ever using a condom.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Knowledge of AIDS among secondary school pupils in Bagamoyo and Dar-Es-Salaam, Tanzania.

We assessed knowledge of AIDS among pupils in selected schools in Tanzania in August 1989. Four hundred and eight-one pupils from four randomly selected secondary schools, two from Dar-Es-Salaam (a city) and two from Bagamoyo (a semi-rural town), were interviewed using a structured questionnaire. Of these, 476 (99.0%) had heard of AIDS, and 447 (92.9%) were able to mention spontaneously at least one sexually transmitted disease (STD), of whom 374 (83.7%) mentioned AIDS. Knowledge was found to increase with age and tended to be higher among women in Dar-Es-Salaam than in Bagamoyo. These data suggest that communication channels directed at women in rural areas should be strengthened. While knowledge of sexual transmission of HIV was generally high, and prevalence of reported misconceptions about modes of transmission was very low, knowledge of non-sexual means of transmission (transfusions, injections, vertical) was lacking. Although 80% of pupils mentioned reduction of number of sexual partners as a means of AIDS prevention, only 22% mentioned condom use, and less than 5% reported that they had ever used a condom. Future research should concentrate on means of promoting sexual behavior change, the ultimate aim of any AIDS prevention strategy.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Willingness to participate in AIDS vaccine trials among high-risk populations in northern Thailand.

OBJECTIVES: To determine the anticipated participation in a prophylactic AIDS vaccine trial and to identify perceived benefits and barriers to enrollment of HIV-seronegative volunteers at risk of HIV infection in northern Thailand. DESIGN: A cross-sectional survey. METHODS: Subjects interviewed in a cross-sectional survey included female commercial sex workers (n = 215), men attending sexually transmitted disease clinics (n = 219), conscripts in the Royal Thai Army (n = 1453), and men discharged from the army (n = 293) who had returned to civilian life. We determined AIDS vaccine knowledge and attitudes, perceived vulnerability to HIV infection, barriers and incentives to participate in a future vaccine trial and agreement to participate in a randomized trial. RESULTS: Awareness of vaccines (88-97%) and AIDS vaccine development efforts (62-77%) were common and viewed to be a complement to behavior change (74-94%). Approximately 25% of subjects would definitely join a trial if asked, and an additional 38% would accept an AIDS vaccine if they were convinced it would be safe and effective. Important barriers to participation included concerns with discrimination (16-45%), short- (37-60%) and long-term (30-55%) vaccine side-effects, fear of disability and death (36-58%), and beliefs that partners would refuse to have sex (24-49%) after immunization. The principal inducement to join a trial was health insurance (62%). CONCLUSION: Potential HIV vaccine trial participants have several fears of joining a vaccine study at this time. Information derived from Phase I/II trials is needed to address these concerns if enrollment in efficacy trials is to be successful in the near future.

AIDS Vaccines↗
PubMed1975

Intrauterine infection of mice with St. Louis encephalitis virus: immunological, physiological, neurological, and behavioral effects on progeny.

Intravenous injection of pregnant mice with St. Louis encephalitis (SLE) virus at 8 days of gestation resulted in infection of the fetus. Progeny developed no antibody or tolerance to SLE virus since the viral antigen was cleared by maternal antibody before antibody-forming competence developed in the young. Temporary growth retardation was observed in a number of young at 3 weeks of age. After the initial setback the growth rate increased, indicating that early runting was due to an inability to adjust adequately to extrauterine life, which was subsequently overcome. In most other young there were no significant effects on growth, reproduction, or life expectancy. A few young died at or shortly after birth; in these, neurological changes ranging from gross defects such as encephaloceles and hydrocephalus to histological evidence of necrosis and congestion were observed. Neurologically related behavioral changes were detected by using the open field test and the rotating-rod test, which indicated neurological damage and memory impairment in the surviving intrauterinely infected animals.

Animals↗
PubMed1992

Time and sex in the male mouse: temporal regulation of infanticide and parental behavior.

Infanticide is a violent but successful reproductive strategy found in many mammals, particularly rodents. In male house mice (Mus domesticus and M. musculus), the act of ejaculation provides a reliable neural signal for timing the birth of their offspring. However, a unique chronobiological aspect of this phenomenon is the extraordinary temporal latency that can occur between the stimulus (coital ejaculation) and its adaptive neural response (male mice cease killing pups and behave parentally toward them instead). Specifically, the inhibition of infanticide is often time delayed for many days after a male ejaculates, but virtually always occurs before or around the time his own sired offspring would be born 18-20 days later. Furthermore, infanticide spontaneously reemerges 50-60 days after mating. In CF-1 stock male mice this entire behavioral sequence is synchronized with the female's reproductive cycle, and occurs even in the total absence of social cues or changes in pituitary or gonadal hormones after mating. When entrained and mated at 22 h (light:dark 11:11) or 27 h (light:dark 13.5:13.5) T-cycles, photoperiodic cues appeared to synchronize this dramatic shift in behavior, because a sudden transition from pup killing to parenting was matched with the number of light/dark cycles experienced after ejaculation rather than the amount of real time experienced, suggesting a circadian timing link. Housing in constant light accelerated the postmating transition to parenting, whereas constant dark significantly delayed the transition to parenting, but still occurred by 3 weeks after mating. Most males tend to oscillate between infanticide and parental behavior for several days before locking in to constant parenting, regardless of lighting conditions. Variation in the time delay between ejaculation and the inhibition of infanticide was consistent within young individuals (< 10 months of age), but in older males (> 18 months of age) the time interval between ejaculation and parenting was significantly prolonged and attenuated. Another unique aspect of this phenomenon is that variation among individuals in their timing and response to light cues is correlated with phenotypic variation in sex steroid exposure during late fetal development. So far, no simple physiological explanation can account for the neural mechanism triggered by ejaculation that coordinates these time-delayed behavioral changes toward pups.

Animals↗
PubMed1988

The ethics of safe sex.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Project Redirection: evaluation of a comprehensive program for disadvantaged teenage mothers.

An evaluation of Project Redirection, a two-year demonstration program designed to help pregnant teenagers and teenage mothers, shows that teenagers from a comparison group, who were not enrolled in the demonstration program, were significantly more likely than project participants to experience a repeat pregnancy after one year, but that after two years the difference was small and nonsignificant. Likewise, at 12 months into the program, the project participants proved more likely to be using contraceptives, but by 24 months the comparison group had caught up. After one year of participation, the project teenagers were more likely than the others either to be in school or to have graduated (56 and 49 percent, respectively). However, this differential also disappeared by 24 months. Nonetheless, even at that point, project teenagers who had dropped out prior to joining the program and those who had had a repeat pregnancy were more likely to be in school or to have completed school than were similar comparison teens. Project teenagers also were somewhat more likely to have held a job during the two-year period than were teenagers not enrolled in the program. All in all, the evaluation demonstrated that teenagers who participated in the project and remained in it for more than a year had consistently better outcomes in education, employment and repeat pregnancy than any other group had. Comparison teenagers who had never participated in any special program for pregnant teenagers, on the other hand, demonstrated consistently poorer outcomes than any other group.

Adolescent↗