PubMed Health⌕ Search

Biomedical subjects

A K Slob

Publications and source records attributed to A K Slob.

At least 37 records · Page 2Linked to original sources
PubMed1997

Quantitative estimation of estrogen and androgen receptor-immunoreactive cells in the forebrain of neonatally estrogen-deprived male rats.

Using quantitative immunocytochemical procedures, the total number of estrogen and androgen receptors was estimated in a large number of hypothalamic and limbic nuclei of male rats, in which brain estrogen formation was inhibited neonatally by treatment with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione. The highest densities of estrogen receptor immunoreactivity were observed in the periventricular preoptic area and the medial preoptic area. Neonatally estrogen-deprived males showed a higher estrogen receptor immunoreactivity than control males in the periventricular preoptic area and the ventrolateral portion of the ventromedial nucleus of the hypothalamus, i.e. those brain areas in which sex differences have been reported, with female rats showing a greater estrogen binding capacity than male rats. The highest densities of androgen receptor immunoreactivity were found in the septohypothalamic nucleus, the medial preoptic area, the posterior division of the bed nucleus of the stria terminalis and the posterodorsal division of the medial amygdaloid nucleus. No significant differences in distribution or total numbers of androgen receptors were found between neonatally estrogen-deprived males and control males. These findings suggest that neonatal estrogens, derived from the neural aromatization of testosterone, are involved in the sexual differentiation of the estrogen receptor system in the periventricular preoptic area and the ventromedial hypothalamus. The role of neonatal estrogens in the development of the forebrain androgen receptor system is less clear.

Androstatrienes↗
PubMed1997

Yohimbine, erectile capacity, and sexual response in men.

In a double-blind, placebo-controlled crossover study on a group of men with erectile problems and a sexually functional comparison group, the effect of yohimbine (up to 30 mg/day) was assessed on a number of objective and subjective measures of erectile response through the use of daily logs and psychophysiological laboratory procedures involving response to visual sexual stimulation (VSS). Sexual desire, arousal, and ejaculatory response were also assessed. Results indicated no effect of yohimbine on most aspects of sexual response in sexually functional men. Mixed effects were found on measures of sexual function in men erectile dysfunction, with 3 of 11 men reporting strong positive effects. Under yohimbine, frequency of sexual activities increased, as did self-assessed genital response to VSS. Daily diaries indicated increased sexual arousal and erectile response during masturbation but not intercourse. A number of other measures, including NPT and retrospective summaries of erectile functioning at the end of drug phases, showed no effect. Results are discussed in terms of possible yohimbic effects on psychological factors that modulate overall sexual response, and consequently, erectile response.

Adult↗
PubMed1997

Psychosocial functioning of children, adolescents, and adults following hypospadias surgery: a comparative study.

Used standardized questionnaires to compare psychosocial functioning of 116 children and adolescents (9 to 18 years) and 73 adults (18 to 38 years) operated on for hypospadias, a congenital penile anomaly, with that of 88 and 50 age-matched comparison males, respectively, treated for an inguinal hernia. The relationships of coping with penile appearance, subject age, severity of hypospadias, number of operations, age at final surgery, and type of surgical procedure with psychosocial functioning were also investigated. Hypospadias patients did not exhibit a poorer psychosocial functioning and no significant relationships of various medical characteristics with psychosocial functioning could be discerned. Genital/body perception of hypospadias patients ages 9 to 18 years correlated positively with psychosocial functioning, albeit with low values. These findings are important for psychologists and specialists in the counseling process of hypospadias patients and their parents.

Adolescent↗
PubMed1996

Neonatal inhibition of brain estrogen synthesis alters adult neural Fos responses to mating and pheromonal stimulation in the male rat.

Neonatal inhibition of brain estrogen formation in male rats by administration of the aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD), permanently changes aspects of their mating behavior and partner preference in adulthood. The medial preoptic area receives chemosensory inputs via a sexually dimorphic vomeronasal projection circuit, which responds to reproductively relevant pheromonal cues. The medial preoptic area also receives genital somatosensory inputs via the midbrain central tegmental field and the medial amygdala. We used Fos immunoreactivity as a marker of neuronal activation to determine whether there is a correspondence between the behavioral profiles of neonatally ATD-treated male rats and their neuronal responses in the medial preoptic area and other brain regions to somatosensory and chemosensory stimuli. Achieving eight intromissions with an estrous female led to a greater neuronal Fos immunoreactivity in the medial preoptic area of neonatally ATD-treated male rats compared with neonatally cholesterol-treated male rats. Exposure for 1.5 h to chemosensory cues derived from soiled bedding of estrous females induced Fos immunoreactivity throughout the vomeronasal pathway (i.e. medial amygdala, bed nucleus of the stria terminalis and medial preoptic area) in both ATD and cholesterol males (Experiment 2a). By contrast, exposure for 1.5 h to chemosensory cues derived from soiled bedding of sexually active males revealed clear differences between ATD and cholesterol males in neuronal Fos immunoreactive (Experiment 2b). At peripheral portions of the vomeronasal pathway (i.e. the accessory olfactory bulb and the medial amygdala), there were no differences in the number of Fos immunoreactivity neurons between ATD and cholesterol males. However, neurons in the more central portions of the vomeronasal pathway (i.e. the bed nucleus of the stria terminalis and the medial preoptic area) showed increased Fos immunoreactivity after exposure to odors from sexually active males in ATD males as opposed to cholesterol males. Females, like ATD males, showed neuronal Fos immunoreactivity at each level of the vomeronasal pathway after being exposed to odors from sexually active males. These results suggest that the responsiveness of neurons in the central portion of the vomeronasal projection circuit to odors from sexually active males, but not estrous females, is sexually differentiated in male rats due to the neonatal action of estrogens.

Androstatrienes↗
PubMed1996

Sexual arousability and the menstrual cycle.

We have repeated a study of the objective (labium minus temperature) and subjective (semantic scales) changes in sexual arousability over the menstrual cycle to erotic video stimulation in 20 women with natural cycles. We extended the study with concomitant vibrotactile stimulation of the clitoral region. In an earlier study women tested for the first time in their follicular phase were sexually more aroused (as indicated by greater increase in labium minus temperature) than women tested for the first time during their luteal phase. When these women were retested in their alternative phase of the menstrual cycle, those who were then follicular did not score higher than those who were then luteal. We then postulated the involvement of a cognitive or conditioned phenomenon which was responsible for the women's repeating their initial phase-dependent response when tested the second time in their alternative phase of the cycle. Identical results were obtained in the present study as far as sexual arousability is concerned during the first test, i.e. follicular women generally scored higher than luteal women; this difference in response persisted during the second test. Concomitant vibrotactile stimulation had no effect on labium minus temperature change but raised subjective sexual arousal and caused a 'more pleasurable' response to the erotic video. Subjective sexual and subjective genital arousal were positively correlated, but neither was significantly correlated with labium minus temperature change. The relationship between menstrual cycle phase and sexual arousal was further substantiated by the reported greater increase in sexual desire after the first erotic video in follicular women than in luteal women. This increased desire, as well as more erotic fantasies, persisted during the next 24 h. In conclusion, studies into effects of menstrual cycle phase on sexual arousability in the laboratory should seriously consider the possible learning and conditioning effects as suggested by the present investigation.

Adolescent↗
PubMed1996

Sexual differentiation of odor and partner preference in the rat.

Previous studies have shown that adult male rats, in which brain estrogen formation was inhibited neonatally by SC administration of the aromatase inhibitor 1,4, 6-androstatriene-3,17-dione (ATD), show an altered sexual partner preference. When tested in a three-compartment box, such gonadally intact ATD males approach and mate both with the estrous female and the sexually active male, whereas normal males prefer to approach and mate with the estrous female, avoiding the stimulus male. After castration in adulthood and estradiol treatment, ATD males prefer sexually active males. Similarly treated normal males prefer estrous females, and estrous females prefer to mate with males. In the present study, we asked what stimulus characteristics of active males vs. estrous females determined the different sexual preferences of males, ATD males, and of females. Were they chemosensory cues or more distal cues such as actually seeing and hearing the stimulus animals or the reward of sexual activity with the stimulus animals? Sex differences in preference were evident when animals were given a choice between soiled bedding from estrous females and from sexually active males. ATD and control males spent significantly more time on soiled bedding from estrous females than on soiled bedding from sexually active males. Control females spent significantly more time on soiled bedding from sexually active males than on soiled bedding from estrous females. More distal cues, such as seeing and hearing the stimulus animals, revealed differences in preference between control males and females, but not between ATD and control males. Physical interaction with the stimulus animals was a prerequisite for revealing differences in preference between ATD and control males. Then, the behavior of ATD males was clearly intermediate between that of normal male and female rats. In conclusion, neonatal estradiol is important for the psychosexual development of the male rat. However, the present data suggest that the psychosexual development of the male rat also requires either prenatal estradiol or perinatal testosterone.

Androstatrienes↗
PubMed1996

Genital and psychoaffective response to erotic stimulation in sexually functional and dysfunctional men.

To understand the sexual response patterns of men with premature ejaculation and erectile dysfunction, the authors compared genital and affective responses of sexually functional and dysfunctional men with 3 types of sexual stimulation: an erotic video, penile vibrotactile stimulation, and a combination of both. Genital response differed across both groups and stimulus conditions, with an interactive effect indicating that groups showed different response patterns depending on the stimulation. Affective responses also differed across groups and interacted with stimulus conditions. The combination genital and affective response was superior to either alone in distinguishing men with no sexual problems from those with erectile or ejaculatory problems (or both). These factors were particularly useful in discriminating men with premature ejaculation from those with combined premature ejaculation and erectile dysfunction.

Adult↗
PubMed1996

Sexual arousal and the quality of semen produced by masturbation.

The influence of sexual arousal on the quality of semen produced by masturbation was investigated. One group of 29 patients referred to our andrology outpatient clinic (group A) and one group of 14 healthy potential sperm donors filled out a questionnaire after having produced two semen samples, at least 1 month apart, by masturbation. Changes in questionnaire scores between first and second visit were compared with changes in semen characteristics between those two occasions to identify statistically significant correlations. A second group of 23 subfertility patients (group B) were asked to produce a semen sample by masturbation in a designated room at the hospital without additional sexual stimulation, and a second sample while viewing a sexually explicit video. Differences in questionnaire scores and semen characteristics obtained with visual erotic stimulation (VES) and without VES were analysed. In group A, the change in sexual arousal and change in intensity of orgasm correlated with change in semen volume (r = 0.38, P < 0.05; r = 0.48, P < 0.01 respectively). In healthy donors and group B, however, no such correlation was found. With VES in group B, significantly higher scores were given for 'feeling at ease/relaxed' (P < 0.01), 'sexual arousal' (P < 0.001), 'quality of erection' (P = 0.01), 'intensity of orgasm' (P < 0.05), 'satisfaction after orgasm' (P < 0.05), and 'ease with which orgasm was achieved' (P < 0.001) with VES compared to without VES. There was no statistically significant improvement in semen quality with VES compared to without VES. It is concluded that sexual arousal has no significant influence on the quality of an ejaculate produced by masturbation. On the other hand, providing a patient with a sexually stimulating video is obviously a facilitative factor when the patient 'has to' produce a semen sample for analysis. The use of visual erotic stimulation is recommended when patients and donors have to produce a semen sample in the university surroundings of a fertility clinic.

Erotica↗
PubMed1996

Satisfaction with penile appearance after hypospadias surgery: the patient and surgeon view.

PURPOSE: We studied the degree of agreement between hypospadias patient and surgeon satisfaction with the cosmetic surgical result, and the relation between penile length, meatal position and patient satisfaction. MATERIALS AND METHODS: Cosmetic and functional results in 35 boys with hypospadias were assessed, and a standardized questionnaire was completed by patients and surgeon. RESULTS: There was hardly any agreement between patient and surgeon satisfaction with patient penile appearance. Patients were less satisfied than the surgeon. No significant correlation was noted between penile satisfaction and penile length. Patients with a retracted meatus were less satisfied with the meatal position than those with a glanular meatus. Of the 35 patients 4 underwent repeat surgery after our study. CONCLUSIONS: Hypospadias surgeons should explicitly asked if patients are satisfied and they should follow patients through adolescence.

Adolescent↗
PubMed1996

Visual erotic and vibrotactile stimulation and intracavernous injection in screening men with erectile dysfunction: a 3 year experience with 406 cases.

To establish the number of patients with erectile dysfunction (ED) who appear to be sexually potent when exposed to visual erotic (VES) and vibrotactile stimulation (VIB) and to investigate whether or not older patients are less responsive to VES/VIB than young patients. Retrospective analysis of data on 406 consecutive patients screened for ED with VES, VES + VIB, VES + Intracavernous injection (ICI). Partial or full erection was obtained in 34% of patients with VES, 52% with VES + VIB, 82% with VES + ICI. Men < 40 y (n = 86) responded better than men > 40; between 40 and 80 no differences in penile responses were found. 50% of patients who reported no morning/night erections appeared to have good, rigid nocturnal penile tumescence (NPT). The use of VES, VES + VIB, VES + ICI is strongly recommended in the screening of men with ED of all ages; up to 80% will respond with a good erection. Only a positive penile response has diagnostic significance. The positive results reduce the necessity for further invasive investigations.

Adult↗
PubMed1995

Increased number of vasopressin neurons in the suprachiasmatic nucleus (SCN) of 'bisexual' adult male rats following perinatal treatment with the aromatase blocker ATD.

In an earlier article an enlarged subpopulation of vasopressin containing neurons was found in the suprachiasmatic nucleus (SCN) of homosexual men as compared to heterosexuals. The present study investigates the possibility that the number of vasopressin neurons in the SCN and sexual partner preference behavior in male rats are both influenced by sex hormones during brain development. For this purpose, we studied groups of adult male rats that had been treated either prenatally or pre- and postnatally with the aromatase inhibitor ATD (1,4,6-androstatriene-3,17-dione) which blocks the aromatization of testosterone to estradiol. Rats treated with ATD in both pre- and postnatal periods showed 'bisexual' partner preference behavior and appeared to have 59% more vasopressin-expressing neurons in the SCN than the controls. The prenatally treated rats did not differ from the controls. This observation supports the hypothesis that the increased number of vasopressin neurons found earlier in the SCN of adult homosexual men might reflect differences that took place in the interaction between sex hormones and the brain early in development.

Androstatrienes↗
PubMed1995

Plasma testosterone in fetal rats and their mothers on day 19 of gestation.

Plasma testosterone levels were higher in pooled samples from male fetuses than from female fetuses on day 19 of pregnancy. Plasma testosterone from female fetuses with males located caudally in the uterus was higher than from females that lacked such males. Testosterone level of both male and female fetuses was correlated with maternal testosterone. No correlation was found between maternal testosterone and number of males in the litter, male-to-female ratio, or litter size. These results corroborate earlier findings of a sex difference in plasma testosterone levels on fetal day 19 in rats, and provide support for the hypothesis that female rats receive androgens from males located caudally in the uterus. No evidence was found that testosterone of pregnant females is affected by the sex ratio or size of her litter.

Androgens↗
PubMed1995

Understanding and diagnosing sexual dysfunction: recent progress through psychophysiological and psychophysical methods.

The psychophysiological method has been applied to the study of human sexual response for well over three decades. The value of this method in providing an objective, integrated approach to the understanding of sexual response, and more specifically sexual dysfunction, is presented. Selected results from recent studies using this methodology illustrate the complex relationships that emerge among cognitive, affective, and physiological components of the sexual response. In addition, data from a systematic study of the use of psychophysiological procedures as an aid in differential diagnosis are given as evidence that this methodology offers a further strategy for assessing problems such as erectile dysfunction and premature ejaculation. Finally, recent findings utilizing sensory psychophysical procedures which relate subjective penile thresholds to sexual response and dysfunction are reviewed. Such procedures also study the interaction of physical/physiological systems with psychological events, and as such may be considered relevant to understanding the relationship between psychological aspects of sexual response.

Female↗
PubMed1995

Postweaning housing conditions and partner preference and sexual behavior of neonatally ATD-treated male rats.

Male rats were neonatally treated with cholesterol or a substance that blocks the aromatization of testosterone to estradiol (1,4,6-androstatriene-3,17-dione: ATD). At weaning (21 days) they were either housed alone or in small groups (2-3 animals) and tested for partner preference behavior (PPB) in adulthood. Choice was between an estrous female and an active male (Part I) and between an estrous female and an ATD-male (Part II). Tests were carried out in a 3-compartment box. Social isolation did not have major effects on PPB except when sexual interaction with the stimulus animals was prevented (Part I). In this case, isolates (ATD and control) showed higher preference scores (PS) for the estrous female and spent less time in the empty middle compartment. When the choice was between an estrous female and an ATD-male, partner PS decreased in all males, most clearly in ATD-males. The latter animals spent more time with the stimulus ATD-male than they had done in previous PPB tests with the normal stimulus male. In contrast to partner preference behaviors, sexual behavior was clearly affected by social isolation. Isolates (ATD and control) displayed lower frequencies of mounts and intromissions. These effects persisted over consecutive tests. Ejaculation was not affected. In conclusion, the present results confirm earlier findings about the significance of neonatal endocrine conditions for the organization of adult PPB in male rats. The presence or absence of social conspecifics after weaning appears to have little influence on adult PPB.

Androstatrienes↗
PubMed1995

Endogenous reproductive hormones and nocturnal rhythms in partner preference and sexual behavior of ATD-treated male rats.

Male rats received subcutaneously silastic capsules, containing the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD), shortly after birth. Control males were given silastic capsules containing cholesterol. The capsules were removed at the age of 21 days. In adulthood, blood serum was collected early and late in the dark phase of the light/dark cycle (experiment I). Testosterone and luteinizing hormone and follicle stimulating hormone (FSH) fluctuated nocturnally, both in ATD and control males, with highest levels late in the dark phase. FSH levels were significantly higher in ATD males. Nocturnal levels of inhibin, a selective suppressor of pituitary FSH secretion, also fluctuated in both ATD and control males, with lowest levels late in the dark phase. In experiment II, ATD and control males were tested for partner preference behavior in a three-compartment box (choice: sexually active male vs. estrous female) early and late in the dark phase. When gonadally intact, ATD males, but not controls, showed a clear nocturnal rhythmicity in partner preference behavior and sexual behavior. Early in the dark phase, such ATD males preferred the vicinity of and interaction with a sexually active male. Late in the dark phase, this preference for the active male shifted to a preference for the estrous female. Control males preferred the estrous female. After castration and subsequent treatment with testosterone via silastic capsules, which ensured constant blood serum levels, ATD males continued to show their nocturnal rhythms in partner preference behavior and in sexual behavior. Thus, the underlying mechanism of the nocturnal rhythmicity phenomenon is an organizational effect of neonatal ATD treatment rather than an activational effect of fluctuating serum hormone levels.

Animals↗