A. Koos Slob
Erasmus University Rotterdam
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by A. Koos Slob.
The Journal of Urology | 1996
Marc A.M. Mureau; Froukje M.E. Slijper; A. Koos Slob; Frank C. Verhulst; Rien J.M. Nijman
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.
The Journal of Urology | 1995
Marc A.M. Mureau; Froukje M.E. Slijper; Rien J.M. Nijman; Jacques C. van der Meulen; Frank C. Verhulst; A. Koos Slob
PURPOSE We studied the psychosexual adjustment, sexual behavior and genital appraisal of 9 to 18-year-old hypospadias patients. MATERIALS AND METHODS We interviewed 116 hypospadias patients and 88 comparison subjects in a semi-structured manner. RESULTS Hypospadias patients had a more negative genital appraisal and anticipated more ridicule by a partner because of penile appearance than comparison subjects but they did not have a different sexual adjustment. No significant impact of medical treatment (surgical procedures, number of operations or age at final surgery) was noted. Many hypospadias patients (38.8%) desired functional or cosmetic penile improvement. CONCLUSIONS In addition to procedures that bring the meatus to a more terminal position, those that bring it more ventral can be performed without negatively affecting psychosexual adjustment. Hypospadias patients were reluctant to seek advice for problems and, therefore, they should be followed through adolescence.
Journal of Sex & Marital Therapy | 1999
Donald S. Strassberg; Carlos A. de Gouveia Brazao; David L. Rowland; Peter Tan; A. Koos Slob
Twenty-three premature ejaculators (PEs) and 11 control subjects were administered 25 mg of clomipramine in a double-blind, placebo-controlled, crossover design study. During 2-week trials, subjects took either the drug or the placebo 4 to 6 hours prior to sexual activity. Daily diary data revealed that, for both groups, orgasmic latency was significantly increased when taking the clomipramine. For the PEs, the average increase in orgasmic latency during intercourse was from less than 1 minute to more than 3.5 minutes. Subjects also participated in two laboratory sessions while on the drug and placebo. During these lab sessions they were exposed to erotic videos with and without the addition of vibrotactile stimulation to the penis. Results from the laboratory data support those from the diaries. Specifically, PEs were significantly less likely to reach orgasm during the lab sessions while on the clomipramine than while on the placebo. Further, they reported a significantly greater sense of control over their orgasm while on the drug. The results of this study, along with previous research, strongly support the value of low doses of clomipramine in the treatment of premature ejaculation, specifically when taken on an as-needed basis as little as 4 hours prior to sexual activity. It is important to note, however, that the beneficial effects of the drug were not uniform across clinical subjects. In this study, those PEs with the shortest orgasmic latencies while on the placebo were the least likely to substantially improve while on the drug. Additional research is necessary to determine whether changes in the timing and dosage of the clomipramine administration can extend the benefits of the drug to those with the shortest latencies.
Journal of Psychosomatic Research | 2000
David L. Rowland; Donald S. Strassberg; Carlos A. de Gouveia Brazao; A. Koos Slob
OBJECTIVE Men with premature ejaculation (PE) exhibit diminished control over and short latency to ejaculation. The present study attempted to delineate further characteristics of men with PE and to address a number of presumed hypotheses regarding the etiology of this disorder. METHODS Twenty-six men with PE were compared with an age-matched group of 13 sexually functional men on multiple indices of erectile and ejaculatory response during coital and masturbatory activities. These data were collected through retrospective, prospective, and laboratory methods. RESULTS Psychophysiological testing indicated greater ejaculatory vulnerability to penile stimulation, although not visual erotic stimulation, in PE men than functional controls. PE men also showed subtle anomalies in the way they perceived their somatic response. The correlation between measures of ejaculatory latency and control was positive and high for intercourse, but low or even negative for masturbation. Whereas functional men showed consistency in ejaculatory latency over coital and masturbatory activities, PE men exhibited much shorter latencies during coitus than masturbation. Data collected under various methodologies (retrospective, prospective, and laboratory) showed greater consistency among sexually functional subjects; and preliminary analysis of laboratory data suggests psychophysiological methodology is as effective in differentiating dysfunctional from functional men as prospective and retrospective methodologies. CONCLUSION Although ejaculatory latency and control tend to be related, these measures are not always stable over different kinds of sexual activity or using different methods of data collection. Psychophysiological methodology is effective in differentiating group membership (PE vs. control), but does not predict individual ejaculatory responses measured prospectively.
Physiology & Behavior | 1996
Julie Bakker; Jan van Ophemert; A. Koos Slob
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.
Physiology & Behavior | 1975
A. Koos Slob; Jacob J. van der Werff ten Bosch
Abstract Adult male rats are larger than females, due to a persistent difference in the growth rate from puberty onward. Gonadectomy at birth abolished, whereas gonadectomy on Day 21 caused a diminution of the sex differences. There were no differences in growth pattern between females spayed at birth and females spayed on Day 21. In male rats this was different: males castrated at birth became lighter and smaller than males castrated on Day 21. Thus males castrated at birth and females spayed at either age grew at comparable rates which were below the growth rate of males castrated at 21 days. This demonstrated the significant role of the neonatal testes on subsequent growth; prepuberal ovaries did not seem to play an important role. The administration of testosterone propionate (TP) to female rats prenatally suppressed growth of intact, but not of females spayed at birth. This TP effect is ovary-dependent. TP given neonatally promoted growth independently of the ovaries. It is concluded that neonatal androgens organize mechanisms which regulate subsequent body growth in the male rat, and that from puberty on ovarian secretions suppress the growth rate. These opposite actions of the gonads cause the sex differences in body growth of the rat.
Physiology & Behavior | 1986
A. Koos Slob; Tom Huizer; J.J. van der Werff ten Bosch
The effects of age and gonads were studied in rats subjected to open-field tests, during which ambulation behavior was recorded. Subjects were three groups of male and female rats: sham-operation on day 1 and day 21; gonadectomy on day 1 and sham-operation on day 21; and sham-operation on day 1 and gonadectomy on day 21. Half of each group were tested in a circular open field (3 min/day, 3 consecutive days) on days 28-30; the others were tested on days 47-49. Representatives of both batches were tested again in a square open field on days 76-78. There was a sex difference in ambulation at 77 days, but not at earlier ages. In animals gonadectomized on day 1 or day 21 the sex difference in adulthood failed to occur, because castration caused the males to ambulate as much as sham-operated and ovariectomized females. On the basis of our results and reports in the literature it is suggested that testicular secretions around puberty have an organizing effect on ambulation behavior. The intact adult male rat ambulates less than the adult female and this difference persists after castration in adulthood. Castration well before puberty prevents the development of the adult sex difference.
Journal of Abnormal Psychology | 1996
David L. Rowland; Stewart E. Cooper; A. Koos Slob
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.
Behavioural Brain Research | 1981
A. Koos Slob; H. Bogers; M.A. Van Stolk
Two experiments were carried out to investigate the contribution of gonadal hormones to the expression of sex differences in open field behaviour of adult female and male rats. In the first experiment rats were gonadectomized or sham-operated in adulthood and tested in the open field 1, 2, 3, 4, 5 or 6 weeks later (3 min/rat on 3 consecutive days during the light period of the day). It was found that following gonadectomy the well known sex difference in ambulation and rearing behaviour (females more than males), as well as in defaecation (females less than males) remained. Ovariectomy caused a decrease in ambulation and rearing, with an increase in defaecation, whereas castration had no significant effect on ambulation and rearing, but also increased defaecation. Also an overall increase in ambulation and rearing was found: animals tested 5 and 6 weeks following the operation were significantly more active than animals tested at 1-4 weeks after the operation. In the second experiment female and male rats were gonadectomized and 7 weeks later they received a silastic implant containing testosterone (T), dihydrotestosterone (DHT), oestradiol (E2), DHT plus E2, or nothing (control condition). Four weeks after the implantation the animals were tested in the open field (3 min/rat on 3 consecutive days). An overall sex difference was found for ambulation (females more than males) and for defaecation (females less than males). The only effect of hormone administration was found in DHT-treated animals: lowest ambulation and highest defaecation compared to other hormone and control animals. No differences were found between the T, E2, DHT plus E2, and control animals. From these data it was concluded that endogenous gonadal steroids seem to play a minor role in the expression of sex differences in adult open field behaviour in the rat.
Physiology & Behavior | 1987
A. Koos Slob; L.W.L. deKlerk; T. Brand
Ovariectomized female rats, longterm treated with estradiol benzoate (EB, 20 micrograms, 3 x/week) or testosterone propionate (TP, 0.4 mg, 3 X/week), were tested for homo- or heterosexual partner preference behavior with either tethered animals (sexually active male vs. estrous female) or animals behind a wire mesh. A preference score was calculated by subtracting the time spent in the vicinity of the stimulus female from the time spent in the vicinity of the stimulus male. Thus, a positive score indicates preference for the male (heterosexual preference), a negative score preference for the female (homosexual preference). Two weeks of EB treatment caused a clearcut preference for the male incentive. This heterosexual preference was significantly different from the indistinct preference of the TP-treated females. Sexual interaction with a freely moving active male (with or without a vaginal mask which prevented intromissions) did not alter the preference for the male of the EB-treated females. It did affect, however, the preference behavior of the TP-treated females significantly: it changed in the direction of the sexually active estrous incentive female, i.e., a homosexual preference. This change in preference could not be attributed to the experience of penile intromissions, it occurred despite the presence of a vaginal mask. Apparently, being mounted by a sexually active male had a negative reinforcing value in the TP-treated female rats and provoked a homosexual partner preference.