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PubMed2003

[Estrogens and synaptic plasticity].

Estrogens influence morphology of the brain not only in structures linked to reproductive cycle and reproductive behavior but also structure engaged in memory and cognitive functions. Estrogens stimulate synaptogenesis in pyramidal neurons of CA1 field of hippocampus. Increase in the number of spines on apical dendrites in rats occurs in the prostures phase of the cycle as well as exogenous estradiol application in ovariectomized females. The new synapses are enriched in NMDA receptor and it was found that their generation involves activation of NMDA receptors, PKA and CREB. Estradiol-induced synaptogenesis is accompanied by facilitation of LTP induction. Estradiol affects pyramidal cells of CA1 probably by inhibiting GABA-ergic interneurons. It also modulates unspecific activatory systems, which contribute significantly to neuroplasticity.

Animals↗
PubMedDate not supplied

[Regulation of reproductive medicine in North America or the Wild West of Medicine (Part I)].

The objective of this work is to offer a general introduction of the legal regulation of the Reproductive Medicine that is practiced in the United States of America. In the United States, besides the Federal Administration, there are also fifty state juridical instances who have competence in Assisted Reproduction subjects. The first section studies the limits of the Right to Reproduction. The American Constitution, interpreted by the Supreme Court, has been useful to establish the limits. Then, will be analyzed the reasons that have been taken by the legislator to adopt a permission with regard to issues appeared by the Medicine of the Fertility. Once studied the general context of the regulation of the Procreation Technology, it is exposed the state legislation and jurisprudence about the matter, and it is also made a review to the most relevant doctrine opinions of the american jurist in relation to Assistance to Reproduction. The cultural and juridical answers that these new clinic methods have used to control, improve or limit the reproduction capacity of human beings are almost as interesting as the Reproductive Technology. Contrary to what happens in Europe, where the legislator has firmly establish the regulation of the Reproductive Medicine since the late 80's, in North-America the lack of regulation has caused a free market where all kind of treatments of fertility are offered, just up to the point that an American author has called the sector "wild west of the Medicine".

Human Rights↗
PubMedDate not supplied

[Contraceptive practices among adolescents and youths of the metropolitan area of Mexico City].

The purpose of this article is to provide a brief description of the information that the adolescent and youth population of Mexico City has concerning the knowledge and use of contraceptive methods, as well as the reasons why they do not adopt some contraceptive method during their sexual relations. The data obtained from the Survey on Adolescent and Youth Reproductive Behavior in the Metropolitan Area of Mexico City serves as a basis for pointing out several behavior patterns of the male and female population from 10 to 25 years of age. Of those interviewed, 32.7 per cent had had at least one sexual contact; the average age at which sexual relations had begun was 16 years for males and 17 for females. A total of 33.8 per cent of those who had had sexual contact stated that they had used some form of contraception, the principal methods used during first sexual intercourse being rhythm (36.9%); withdrawal (23.6%), and condoms (12.3%). The reasons for not using any contraceptive method were as follows: lack of knowledge regarding the methods, how to use them or where to obtain them (39.4%), and unplanned sexual intercourse (28.9%). During the last sexual contact they had, 70.5 per cent had used a contraceptive. The methods most frequently used were hormonal contraceptives and IUD (40.9%); rhythm (23.8%), and withdrawal and condoms. The reasons why no contraceptive was used in the last sexual contact were: neither partner thought that pregnancy would occur (27.1%) and the sexual contact was unplanned.

Adolescent↗
PubMed1992

Underreporting of abortion in surveys of U.S. women: 1976 to 1988.

Although research on reproductive behavior depends heavily on information from surveys, abortions are characteristically underreported in such data. Estimates of the level of reporting are made for each of the recent major surveys of U.S. women: the 1976, 1982, and 1988 cycles of the National Survey of Family Growth, the 1976 and 1979 National Surveys of Young Women, and the National Longitudinal Surveys of Work Experience of Youth. The estimates are based on comparisons with external counts of abortions taking place. We examine variation by characteristics of women, trends over time, and the possible effects of length of recall and of the way in which questions about abortion are asked. Abortion reporting is found to be highly deficient in all the surveys, although the level varies widely. Whites are more likely to report their abortions than nonwhites. Special, confidential questioning procedures hold promise for improving the results.

Abortion, Legal↗
PubMed1992

[20 years of a sex education clinic. Are family planning centers still needed?].

The Sexual Information Clinic in Oslo was founded more than 20 years ago. The clinic is the largest family planning centre in Norway, treating 4,000-6,000 patients per year. In recent years the treatment of venereal diseases has become the major component of the daily work. The authors describe the different groups of patients who visit the clinic. The meanage of the patients is 21 years. The high number of legal abortions among younger women and the rising incidence of sexually transmitted diseases prove the continued existence of a need for family planning centres. The authors discuss the situation of family planning centres in Norway in general and stress the importance of their work. They argue that all venereal diseases should be treated free of charge.

Adolescent↗
PubMed1992

[The mechanism of the pineal gland in inhibiting sexual receptivity of female rats: (II) Does it concern progesterone?].

The present study was designed to find the role of progesterone in modulating the effect of pineal gland upon reproductive behavior in the female rat. Monosodium L-glutamate (MSG) was used as a neurotoxin to induce hypogonadal function. In the first part of the experiment, rats were divided into four groups: (1) normal, (2) pinealectomized (Px), (3) MSG-treated (MSG), and (4) pinealectomized MSG-treated (Px-MSG), as immature rats became mature, the IEC (Incidence of Estrous Cycle) in each group was determined by vaginal smear for three weeks. Serum samples for estimating the levels of progesterone were collected at estrous. Then, ovariectomy was performed. Two weeks later, estradiol was primed for three days following progesterone administration and sexual receptivity as well as solicitation were observed. The results showed that, the serum progesterone levels and IEC of Px-MSG rats were significantly higher than that of the MSG group. In addition, Px and Px-MSG rats showed a higher sexual receptivity than normal and MSG rats, respectively. In the second part of the experiment, rats were divided into two groups: (1) normal and (2) Px. All rats were ovariectomized at 2.5 months of age and implanted with a 2-mm 20% estradiol benzoate-filled silastic capsule. Then, sexual receptivity to various doses of progesterone (0, 0.02, 0.1, 0.5 mg/rat) were observed. The results showed that receptivity of Px rats was significantly higher than that of the normal ones in a dose-dependent manner. It is concluded that pineal gland plays an important role in the regulation of ovary function as well as sexual receptivity in female rats. Also, progesterone may be one of the factors modulating the effect of pineal gland on sexual receptivity.

Animals↗
PubMed2005

Reasons for delaying childbearing--a survey of women aged over 35 years seeking assisted reproductive technology.

BACKGROUND: Many women seeking assisted reproductive technology for their first planned pregnancy may be unaware of the impact of age on fertility. METHOD: An anonymous mailed survey to women aged over 35 years with no previous planned pregnancies, registered with Monash IVF between January 2002 and May 2003. RESULTS: One hundred and fifty-two out of 266 surveys were completed (57%). The most common reported reasons for delaying pregnancies were: not having a partner (50%), wanting financial security (32%) and a career (19%) before having a family, only recently becoming interested in having children (26%), and being unaware of the impact of age on fertility (18%). DISCUSSION: Some reported reasons for delaying childbearing were beyond personal control. Lack of awareness of the impact of age on fertility may have contributed to the delay in a proportion of the women surveyed.

Adult↗
PubMedDate not supplied

[Evolution as resistance to entropy. I. Mechanisms of species homeostasis].

The idea is discussed that the common output of any evolution is creation of the entities that are increasingly resistant to further evolution. The moving force of evolution is entropy, the tendency to disorder. This general aspiration for chaos is a cause of the mortality of organisms and species, however, being prerequisite for any movement, it creates (by chance) novelties, which may occur (by chance) more resistant to further decay and thus survive. The surviving of those who survive is the most general principle of evolution discovered by Darwin for particular case of biological evolution. The second law of thermodynamics states that our Universe is perishing but its ontology is such that it creates resistance to destruction. The evolution is a history of this resistance. Not only those who die do not survive but also those who evolve. The entities that change (evolve) rapidly disappear rapidly and by this reason they are not observed among both the fossils and now-living organisms. We know only about long-living species. All the existing organisms are endowed with an ability to resist other changing. The following main achievements of the species homeostasis are discussed: high fidelity of DNA replication and effective mechanisms of DNA repair; diploidy; normalizing selection; truncated selection; heterozygote superiority; ability to change phenotype adaptively without changing genotype; parental care and the K-strategy of reproduction; behavior that provides independence of the environment. The global resistance of the living systems to entropy is provided the state that all the essential in biology is determined not by physical-chemical interactions but could semantic rules. A conception of "potential zygotic information" that determines the rules of ontogenesis is proposed. A zygote does not contain this information in explicit form. It is created de novo step by step during ontogenesis and it could not be decoded beforehand. The experimental data on the adaptive mutagenesis and the relevant hypothesis are discussed. It is concluded that the special mechanisms for speeding-up of evolution as created by evolution are impossible conceptually.

Adaptation, Biological↗
PubMedDate not supplied

Sexual abuse as a factor in adolescent pregnancy and child maltreatment.

Two-thirds of a sample of 535 young women from the state of Washington who became pregnant as adolescents had been sexually abused: Fifty-five percent had been molested, 42 percent had been victims of attempted rape and 44 percent had been raped. Compared with adolescent women who became pregnant but had not been abused, sexually victimized teenagers began intercourse a year earlier, were more likely to have used drugs and alcohol and were less likely to practice contraception. The abused adolescents were also more likely to have been hit, slapped or beaten by a partner and to have exchanged sex for money, drugs or a place to stay. Young women in the abused group were also more likely to report that their own children had been abused or had been taken from them by Child Protective Services.

Adolescent↗
PubMedDate not supplied

[Acceptance and rejection of vasectomy in rural males].

BACKGROUND: One problem in rural population is the gap between coverage of contraception and scant masculine participation, which could be due to lack of information of to other sociocultural factors. METHODS: We investigated, in two stages, the characteristics or the profile of the sexual and reproductive behavior of males in an exploratory study by means of focus groups to determine their relevant motivations and characteristics and subsequently, a structured questionnaire to ascertain the magnitude of the factors explored. The population corresponded to zones of rural hospital medical services zones of medical services in seven ethnic groups of the Mexican Republic and included men who accepted and who rejected vasectomy. RESULTS: The profile of males who accepted vasectomy allowed to determine that there exist a unsatisfied demand for contraceptive protection and the desire of not having additional children; in addition, we found that the decision to accept vasectomy is determined to a greater extent for reasons different from that of information on the contraceptive method. The important proportion of males who were non-users of contraceptive methods who accepted vasectomy supposed information on contraception to be the most consistent reason; nonetheless, this information was not considered sufficient and timely; thus, adverse economic situation, a certain condition related with the couple such as health or love for the female partner are the more weighty reasons for deciding to accept vasectomy, while the fear of poor sexual performance is the most powerful factor for rejection of vasectomy. CONCLUSIONS: Masculine participation in family planning is a factor that conditions contraceptive coverage and its respective benefits. The profile of the male who accepts vasectomy aids in identifying candidates forthe procedure and in reducing unsatisfied demand. Greater diffusion of information of the contraceptive method of vasectomy, greater links between male needs and vasectomy, and maintaining or increasing access to family planning are required.

Adolescent↗
PubMedDate not supplied

A comparison of the fertility of Dominican, Puerto Rican and mainland Puerto Rican adolescents.

Data from three fertility surveys are used to examined the probabilities and determinants of adolescent births among Dominican and Puerto Rican women. Young women in the Dominican Republic are the most likely to have had a child by each year of age from 14 through 24, followed by young women on the Island of Puerto Rico; the probability of an early birth is lowest for Puerto Rican women on the U.S. mainland. Eighteen percent of Dominican women have had a child before their 18th birthday, compared with 13% of women living in Puerto Rico, and 10% of Puerto Rican women in metropolitan New York. The cumulative probabilities that Puerto Rican women will have borne a child before their 20th birthday are almost identical, whether the women live on the island or the U.S. mainland, but the difference between Puerto Rican and Dominican women widens. The order is reversed, however, in the analysis of premarital births: The probability of a premarital birth during adolescence is highest for Puerto Rican women in New York, and lowest for Dominican women. In a separate logistic regression analysis, education and age at first sexual intercourse are shown to be important determinants of adolescent fertility in all three populations.

Adolescent↗
PubMedDate not supplied

Methuselah moms.

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Adult↗