Warmteregulatie van de testikel

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Publicaties over de verstoring van de thermoregulatie van de testikels

Onderstaande publicaties gaan over de rol van de warmteregulatie van de testikels en de spermakwaliteit van de man. Meer over de rol van de man, leest u op de pagina de rol van de man.

1. Eur J Obstet Gynecol Reprod Biol. 1988 Oct;29(2):137-41

Influence of occupation and living habits on semen quality in men (scrotal insulation and semen quality)

Auteurs: Laven JS, Haverkorn MJ, Bots RS.

Department of Anatomy, School of Veterinary Medicine, State University Utrecht, The Netherlands.

Fifty-six males from infertile couples were categorised into two different groups and their semen quality examined. Patients in which there was no evidence of interference with normal testicular thermoregulation either during the day or the night were classified as 'cool workers' and 'cool sleepers' (Group I, n = 26). In the other group (II), 'warm workers'/'warm sleepers' (n = 30), there was evidence for scrotal insulation. The number of good moving spermatozoa per ejaculate as well as this number per ml was greater in 'cool workers'/'cool sleepers' than in 'warm workers'/'warm sleepers' (p less than 0.001). These results emphasize the need for comprehensive patient history when evaluating infertility problems. Similarly, living habits may play a role in human male infertility and treatment.

2. Int J Androl. 2005 Apr;28(2):93-8

Improvement of semen quality by nocturnal scrotal cooling in oligozoospermic men with a history of testicular maldescent.

Auteurs: Jung A, Schill WB, Schuppe HC.

Center of Dermatology and Andrology, Justus Liebig University, D-35392 Giessen, Germany. andreas.jung@derma.med.uni-giessen.de

For infertile men with a history of testicular maldescent only few therapeutic options exist beside assisted reproduction. The aim of our study was to evaluate the influence of nocturnal scrotal cooling on semen quality in such patients presenting with oligozoospermia. Twenty infertile men with a history of testicular maldescent and oligozoospermia were included for nocturnal scrotal cooling over 12 weeks for every night. To increase nocturnal periscrotal air circulation we used a membrane pump connected via plastic tubes to receptacles placed in both groins. Semen analysis was performed at the beginning of the cooling period and at weeks 4, 8 and 12. Another 20 infertile patients with a history of testicular maldescent and oligozoospermia were followed without specific treatment and served as a retrospectively built control group. Scrotal cooling at night by means of a perigenital air stream resulted in a scrotal temperature drop by 0.8 degrees C (median). A significant increase in sperm concentration and total sperm count was achieved by nocturnal cooling after 8 weeks (p < 0.01; p < 0.05; respectively) and 12 weeks (p < 0.01; p < 0.01; respectively). The improvement of sperm motility and sperm morphology was statistically insignificant. The present study suggests nocturnal scrotal cooling as a therapeutic option to improve semen quality. In a further controlled prospective study the influence on pregnancy rates should be evaluated.

3. Reproduction. 2001 Apr;121(4):595-603.

Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress in men with oligoasthenoteratozoospermia.

Auteurs: Jung A, Eberl M, Schill WB.

Center of Dermatology and Andrology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany. Andreas.Jung@derma.med.uni-giessen.de

A questionnaire assessing factors that might cause an increase in scrotal temperature was completed by patients with reproducible oligoasthenoteratozoospermia of idiopathic nature or caused by varicocele. Evaluation by means of a grading scale revealed increased scrotal heat stress in oligoasthenoteratozoospermic patients compared with normozoospermic men (P < 0.01). In addition, long-term determination of 24 h scrotal temperature profiles showed that compared with semen donors, oligoasthenoteratozoospermic patients frequently had scrotal temperatures above 35.5 degrees C despite the same environmental temperatures (P < 0.05). In 88% of cases, maximum scrotal temperatures were measured during rest or sleep phases, whereas minimum values were recorded during physical activity or frequent change of position. Nocturnal scrotal cooling by means of an air stream resulted in a decrease in scrotal temperature of approximately 1 degrees C. Furthermore, a highly significant increase in sperm concentration (P < 0.0001) and total sperm output (P < 0.0001) was achieved after nocturnal scrotal cooling for 12 weeks together with a moderate decrease in factors leading to genital heat stress. A significant improvement in sperm motility (P < 0.05) and sperm morphology (P < 0.05) was also observed, but this improvement was markedly less pronounced than the changes in sperm concentration. This study shows the importance of genital heat stress as a cofactor in fertility impairment in men and indicates nocturnal scrotal cooling as a therapeutic option.

4. Int J Androl. 2004 Feb;27(1):5-11

Semen quality and sedentary work position.

Auteurs: Stoy J, Hjollund NH, Mortensen JT, Burr H, Bonde JP.

Department of Occupational Medicine, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus, Denmark. stoey@stofanet.dk

Increased scrotal temperature can, in experimental settings, markedly disturb the production of semen. Sedentary work position may increase the temperature of the scrotum, but previous studies have failed to determine whether changes in scrotal temperature caused by sedentary work actually do affect semen quality. This study was carried out to elucidate the possible harmful effects of sedentary work on sperm count and other semen characteristics. In 1981-1983 a semen sample was obtained from 3119 men who attended an infertility workup in one of four Danish fertility centres. A total of 2517 men returned a postal questionnaire with information on life style, leisure time activities, occupational history and job duties. Information on job specific work position was obtained from The Danish Work Environment Cohort study 1990 (DWECS). In this analysis DWECS data for a total of 1747 men was included from men aged 18-39 years with >30 h of work per week. For all job titles represented in the DWECS, the mean proportion of sedentary work was estimated. The sperm cell concentration was 30.6 million/mL among men in the quintile with lowest job specific sedentary work compared with 40.5 million/mL in the highest quintile. The difference was, however, not statistically significant. Stratification on infertility period, educational level of the man, fertility centre, and fertility-related disease of the spouse did not influence the results. The analyses do not suggest that sedentary work is a risk factor for abnormal semen characteristics.

5. Hum Reprod. 2002 Jul;17(7):1837-8

Correlation of scrotal temperature in twins.

Auteurs: Hjollund NH, Storgaard L, Ernst E, Bonde JP, Christensen K, Olsen J.

Department of Occupational Medicine, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus C, Denmark. hhjol@akh.aaa.dk

BACKGROUND: Scrotal temperature and semen quality have been found to be inversely correlated in several studies, and variation in scrotal temperature may contribute to the well known variation in semen quality. The reason for the variation in scrotal temperature is not well understood although determinants could be of a genetic nature. METHODS: We monitored scrotal skin temperature for 24 h in a group of monozygotic and dizygotic twins and single-born brothers (n = 48 males). A thermistor was attached to the underwear and the temperature of the scrotal skin was recorded every 5 min using a small portable data logger. RESULTS: A correlation in median scrotal temperature was found among monozygotic twins (r = 0.64, P = 0.01), but not in dizygotic twins and single-born brothers (r = 0.17, NS). Similar results were found for other percentiles of temperature. CONCLUSIONS: The results suggest a genetic component to the variation in scrotal temperature. An hereditary element in male fecundity may be expressed through scrotal temperature, which constitutes a mechanism independent of those responsible for the development of the sperm producing epithelium.

6. Reprod Toxicol. 2002 May-Jun;16(3):209-14

The relation between daily activities and scrotal temperature.

Auteurs: Hjollund NH, Storgaard L, Ernst E, Bonde JP, Olsen J.

Department of Occupational Medicine, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus, Denmark. hhjol@akh.aaa.dk

Normal sperm production depends on a testicular temperature below body temperature, but the thermogenic effects of daily life activities are not well known. We described the association between scrotal temperature and daily activities in 101 males using a non-invasive method for measuring scrotal temperature. A thermistor was attached to the underwear and the temperature of the scrotal skin was logged by a portable device every 5 min for 24h. Participants reported sedentary position and activities at work and during spare time in a questionnaire. Scrotal temperature was strongly correlated with sedentary work position with a dose-effect association (<1 h sedentary: 33.1 degrees C, >6 h sedentary: 34.7 degrees C, median values). The variation in sedentary work accounted for 31.5% of the variation in median temperature during the entire 24h. Sedentary position during spare time did not correlate with scrotal temperature. Median temperature at night was 1.2 degrees C higher than during the daytime. No effect was found for size or reported tightness of the underwear. In a model experiment, the deviance between testicular and scrotal temperature was estimated as maximally 0.1-0.6 degrees C, depending on the type of activity. Measuring scrotal temperature provides a valid estimate of testicular temperature and is feasible in large cohorts. We conclude that work position is an important determinant of testicular temperature.

7. Reproduction. 2001 Apr;121(4):595-603

Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress in men with oligoasthenoteratozoospermia.

Auteurs: Jung A, Eberl M, Schill WB.

Center of Dermatology and Andrology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany. Andreas.Jung@derma.med.uni-giessen.de

A questionnaire assessing factors that might cause an increase in scrotal temperature was completed by patients with reproducible oligoasthenoteratozoospermia of idiopathic nature or caused by varicocele. Evaluation by means of a grading scale revealed increased scrotal heat stress in oligoasthenoteratozoospermic patients compared with normozoospermic men (P < 0.01). In addition, long-term determination of 24 h scrotal temperature profiles showed that compared with semen donors, oligoasthenoteratozoospermic patients frequently had scrotal temperatures above 35.5 degrees C despite the same environmental temperatures (P < 0.05). In 88% of cases, maximum scrotal temperatures were measured during rest or sleep phases, whereas minimum values were recorded during physical activity or frequent change of position. Nocturnal scrotal cooling by means of an air stream resulted in a decrease in scrotal temperature of approximately 1 degrees C. Furthermore, a highly significant increase in sperm concentration (P < 0.0001) and total sperm output (P < 0.0001) was achieved after nocturnal scrotal cooling for 12 weeks together with a moderate decrease in factors leading to genital heat stress. A significant improvement in sperm motility (P < 0.05) and sperm morphology (P < 0.05) was also observed, but this improvement was markedly less pronounced than the changes in sperm concentration. This study shows the importance of genital heat stress as a cofactor in fertility impairment in men and indicates nocturnal scrotal cooling as a therapeutic option.

8. Int J Androl. 2000 Oct;23(5):309-18

Diurnal scrotal skin temperature and semen quality. The Danish First Pregnancy Planner Study Team.

Auteurs: Hjollund NH, Bonde JP, Jensen TK, Olsen J.

Department of Occupational Medicine, Aarhus University Hospital, Denmark. hhjol@aaa.dk

It is well established that heat is associated with reduced sperm production, but the role of physiological variation in temperature has never been scrutinized in humans. We studied diurnal scrotal temperature and markers of male fertility in a population of couples planning their first pregnancy. Sixty men from a cohort of couples who were planning their first pregnancy were included and scrotal skin temperature was monitored during 3 days using a portable data recorder. Working hours and working postures were recorded daily in a questionnaire. Each man provided a fresh semen sample and the couples were followed for six menstrual cycles or until a clinical pregnancy was recognized. The median value of scrotal skin temperature was 33.3 degrees C in the daytime and 34.8 degrees C at night. In periods of sedentary work, the median temperature was on average 0.7 degrees C higher (SE=0.2 degrees C). In addition, scrotal temperature was higher in the daytime, in summer, and in leisure time compared with working hours. Median sperm concentration among men with more than 75% of their daytime readings above 35 degrees C was 33.4 x 10(6)/mL, compared with 91.8 x 10(6)/mL for men with less than half of their readings above 35 degrees C (difference 58.4; 95% CI: 25.9-77.8 x 10(6)/mL). It is concluded that a sedentary position is a significant source of increased scrotal skin temperature, and even moderate and physiological elevation in scrotal skin temperature is associated with a substantially reduced sperm concentration. Sedentary work should be considered as an important potential confounder for reduced sperm count in epidemiological research.

9. Hum Reprod. 1998 Aug;13(8):2122-5

Occupational heat exposure and male fertility: a review.

Auteurs: Thonneau P, Bujan L, Multigner L, Mieusset R.

Department of Epidemiology, Public Health and Human Reproduction, INSERM U-292, Toulouse, France.

In humans, as in most mammals, spermatogenesis is temperature dependent. This temperature dependence has been clearly demonstrated by several experimental studies showing that artificial increases in scrotum or testicle temperature in fertile men reduce both sperm output and quality. Our knowledge of the effects of occupational heat exposure on male fertility comes mostly from a small number of epidemiological studies. We conducted an extensive review of these published reports, focusing on methodology and design (retrospective or prospective; reference group; number of subjects) and principal results (using several indicators such as the time taken to obtain a pregnancy or sperm characteristics). We concluded that occupational heat exposure is a significant risk factor for male infertility, affecting sperm morphology and resulting in delayed conception. The limits and biases involved in this type of research are also discussed.

10. Fertil Steril. 1997 Aug;68(2):334-9

Effect of increased scrotal temperature on sperm production in normal men.

Auteurs: Wang C, McDonald V, Leung A, Superlano L, Berman N, Hull L, Swerdloff RS.

Department of Medicine, Harbor-University of California, Los Angeles Medical Center, Torrance 90509-2910, USA. WANG@HARBOR6.HUMC.EDU

OBJECTIVE: To determine whether application of polyester-lined athletic supports to bring the testes closer to the abdomen increases scrotal temperature and decreases sperm production. DESIGN: Prospective clinical study. SETTING: University academic medical center. PATIENT(S): Twenty-one healthy male volunteers. INTERVENTION(S): The study consisted of a pretreatment period of 6 weeks, a treatment phase of 52 weeks, and a recovery phase until return to normal sperm production. During the treatment phase, the men wore polyester-lined athletic supports (single layer, double layer, or double layer impregnated with aluminum) throughout the day. MAIN OUTCOME MEASURE(S): Semen parameters and sperm function tests. RESULT(S): In all three groups of subjects, scrotal temperature was consistently increased by 0.8 to 1 degree C while the subjects were wearing the athletic supports. Mean sperm concentration; sperm motility, morphology, and viability; sperm hyperactivation; and ability of spermatozoa to penetrate zone-free hamster oocytes were not affected by the increase in scrotal temperature. CONCLUSION(S): The increase in scrotal temperature induced by polyester-lined athletic supports was insufficient to cause significant suppression of spermatogenesis or alteration of sperm function.

11. Reprod Toxicol. 1990;4(3):229-32

Fit of underwear and male spermatogenesis: a pilot investigation.

Auteurs: Sanger WG, Friman PC.

University of Nebraska Medical Center, Omaha.

We evaluated the effect fit of underwear had on sperm production in two healthy adult males in their early thirties. The subjects alternated from wearing tight fitting bikini type briefs to loose fitting boxer type briefs in an ABAB withdrawal design. Conditions lasted three months and were alternated twice resulting in a one year study. The initial condition for each subject was randomly determined with the laboratory technologist blind to the conditions. Four semen parameters were analyzed in this study: sperm density, total number of sperm, total number of motile sperm, and total number of motile sperm per hour of abstinence. The results showed the semen parameters gradually decreased in tight conditions and gradually increased during loose conditions. Although preliminary, the results support the commonly held but undocumented belief that the fit of men's underwear can influence sperm production.

12. Lancet. 1996 Jun 29;347(9018):1844-5

Tight-fitting underwear and sperm quality.

Auteurs: Tiemessen CH, Evers JL, Bots RS.

Publication Types:

  • Clinical Trial
  • Letter
  • Randomized Controlled Trial
  • 13. Int J Androl. 1997 Oct;20(5):274-8

    Effect of male occupational heat exposure on time to pregnancy.

    Auteurs: Thonneau P, Ducot B, Bujan L, Mieusset R, Spira A.

    Department of Epidemiology, Public Health and Human Reproduction, INSERM, Paris, France.

    The relationship between male occupational heat exposure and the time required to achieve a pregnancy [TTP] was studied in a retrospective survey of 402 fertile couples. The TTP for t he subgroups 'exposure t o heat' (median = 4 .0 months; mean 11.8; SD = 13.3) and 'professional driver >3 h/day' (median = 4.5; mean = 14.4; SD = 28.5) was significantly longer (both p < 0.05) than for the controls (median = 2.8; mean = 7.8; SD = 13.3). Bakers and welders showed comparable results: only 14% of the bakers' partners became pregnant within 3 months (cf. 55% of controls, p < 0.05) and only 29% became pregnant within 6 months (cf. 74% of controls, p < 0.02). This study suggests that occupational exposure to heat is a 'weak' risk factor for male subfertility.

    14. Reproduction. 2001 Apr;121(4):595-603

    Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress in men with oligoasthenoteratozoospermia.

    Auteurs: Jung A, Eberl M, Schill WB.

    Center of Dermatology and Andrology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany. Andreas.Jung@derma.med.uni-giessen.de

    A questionnaire assessing factors that might cause an increase in scrotal temperature was completed by patients with reproducible oligoasthenoteratozoospermia of idiopathic nature or caused by varicocele. Evaluation by means of a grading scale revealed increased scrotal heat stress in oligoasthenoteratozoospermic patients compared with normozoospermic men (P < 0.01). In addition, long-term determination of 24 h scrotal temperature profiles showed that compared with semen donors, oligoasthenoteratozoospermic patients frequently had scrotal temperatures above 35.5 degrees C despite the same environmental temperatures (P < 0.05). In 88% of cases, maximum scrotal temperatures were measured during rest or sleep phases, whereas minimum values were recorded during physical activity or frequent change of position. Nocturnal scrotal cooling by means of an air stream resulted in a decrease in scrotal temperature of approximately 1 degrees C. Furthermore, a highly significant increase in sperm concentration (P < 0.0001) and total sperm output (P < 0.0001) was achieved after nocturnal scrotal cooling for 12 weeks together with a moderate decrease in factors leading to genital heat stress. A significant improvement in sperm motility (P < 0.05) and sperm morphology (P < 0.05) was also observed, but this improvement was markedly less pronounced than the changes in sperm concentration. This study shows the importance of genital heat stress as a cofactor in fertility impairment in men and indicates nocturnal scrotal cooling as a therapeutic option.

    15. International Journal of Andrology Volume 28 Page 93 - April 2005 doi:10.1111/j.1365-2605.2004.00517.x Volume 28 Issue 2

    Improvement of semen quality by nocturnal scrotal cooling in oligozoospermic men with a history of testicular maldescent

    Auteurs: JUNG, W. -B. SCHILL and H. -C. SCHUPPE

    Summary
    For infertile men with a history of testicular maldescent only few therapeutic options exist beside assisted reproduction. The aim of our study was to evaluate the influence of nocturnal scrotal cooling on semen quality in such patients presenting with oligozoospermia. Twenty infertile men with a history of testicular maldescent and oligozoospermia were included for nocturnal scrotal cooling over 12 weeks for every night. To increase nocturnal periscrotal air circulation we used a membrane pump connected via plastic tubes to receptacles placed in both groins. Semen analysis was performed at the beginning of the cooling period and at weeks 4, 8 and 12. Another 20 infertile patients with a history of testicular maldescent and oligozoospermia were followed without specific treatment and served as a retrospectively built control group. Scrotal cooling at night by means of a perigenital air stream resulted in a scrotal temperature drop by 0.8 °C (median). A significant increase in sperm concentration and total sperm count was achieved by nocturnal cooling after 8 weeks (p < 0.01; p < 0.05; respectively) and 12 weeks (p < 0.01; p < 0.01; respectively). The improvement of sperm motility and sperm morphology was statistically insignificant. The present study suggests nocturnal scrotal cooling as a therapeutic option to improve semen quality. In a further controlled prospective study the influence on pregnancy rates should be evaluated.

    16. Reprod Toxicol. 2002 May-Jun;16(3):215-21

    Impact of diurnal scrotal temperature on semen quality.

    Auteurs: Hjollund NH, Storgaard L, Ernst E, Bonde JP, Olsen J.

    Department of Occupational Medicine, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus, Denmark. hhjol@akh.aaa.dk

    A high scrotal temperature is a common finding in infertile patients and experimental studies indicate that specific types of heat exposure reduce semen quality. More and more men have a sedentary work position, which increases scrotal temperature. Semen and blood samples from 99 healthy men were analysed in relation to scrotal skin temperature obtained by a 24-h continuous monitoring protocol. Information on sedentary position at work and during spare time was collected by questionnaires. A negative correlation was found between high scrotal temperature and sperm output. Sperm concentration decreased 40% per 1 degrees C increment of median daytime scrotal temperature (95% CI: 8-71%). Similar results were found for total sperm count, FSH, and inhibin B. Motility, morphology, pH, and testosterone were not significantly associated with temperature. Only weak and inconsistent associations were found between sedentary position and semen quality. We conclude that scrotal temperature and semen quality are closely associated. Sedentary work position encountered in ordinary jobs, although a strong determinant of scrotal temperature, does not seem to have any effect on semen quality.

    17. Br Med Bull. 2000;56(3):630-42

    Lifestyle and environmental contribution to male infertility.

    Auteurs: Sharpe RM.

    MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, 37 Chalmers Street, Edinburgh EH3 9ET, UK.

    This chapter is an overview of recent developments in our understanding and thinking about the importance and nature of environmental effects on sperm counts and fertility in the human male. This area is plagued by imperfect studies, not necessarily because of imperfect design but because of other 'uncontrollable' constraints. The available data, therefore, need to be placed in context and account taken of the limitations of our understanding or, more correctly, our ignorance. As we enter the new millennium, one of the saddest scientific aspects of human reproduction and infertility is our persisting ignorance about the causes and treatment of male infertility. With one notable exception (Y chromosome microdeletions) there has been little advance in our understanding of the causes of male infertility and its direct treatment over the past 20 years. Although most infertile men can now be offered the chance of fertility via ICSI, it is largely ignored that this does not represent treatment of the patient's infertility (which will persist unchanged), but is a means of circumventing the problem and leaving it for the next generation to tackle. There are many reasons for our ignorance about the causes of infertility, and some of these are outlined below in order to emphasise how this limits our ability to establish whether or not specific lifestyle and environmental factors do, or do not, affect human male reproductive function.

    18. Reproduktionsmedizin Verlag : Springer Berlin / Heidelberg ISSN: 1434-6931 (Paper) 1434-808X (Online) DOI:10.1007/s00444-002-0362-2 Heft : Band 19, Nummer 1 Datum : Februar 2003 Seiten : 1 - 8

    Die Samenqualität des Mannes nach testikulärer Überwärmung

    Auteurs: A. Jung, H.-C. Schuppe, W.-B. Schill

    Zentrum für Dermatologie und Andrologie der Justus-Liebig-Universität Gießen

    Zusammenfassung
    Die im Vergleich zur Körperkerntemperatur beim Menschen um mehrere Grad Celsius niedrigere Hodentemperatur ist zur Aufrechterhaltung einer ungestört ablaufenden Spermatogenese unerlässlich.Durch regelmäßige skrotale Erwärmung mittels heißer Wasserbäder von bis zu 47°C kann eine Spermatogenesehemmung mit reduzierter Samenqualität resultieren. Die Entstehung einer Azoospermie ist für den Menschen jedoch nicht belegt.Fieber von mindestens 39°C über mehrere Tage kann ebenfalls zu einer passageren Einschränkung der Samenqualität führen. Hinsichtlich einer Spermatogenesehemmung durch berufliche Hitzeexposition ist die Datenlage dürftig und für die am besten untersuchte Berufsgruppe der Schweißer nicht gesichert. Die Bedeutung einer chronischen Behinderung der perigenitalen Luftzirkulation durch isolierende Kleidung bzw. häufiges und langes Sitzen wird kontrovers diskutiert,wobei methodisch überzeugende Arbeiten eine Verschlechterung der Samenqualität wahrscheinlich machen. Die Behinderung der skrotalen Wärmeabgabe durch isolierende Suspensorien in kontrazeptiver Absicht erbringt nach den vorliegenden Daten nur eine bescheidene Verschlechterung für die Spermatozoendichte auf 25-50% der Ausgangswerte.Die Verbesserung der skrotalen Wärmeabgabe durch Umsetzung verschiedener Kühlprinzipien führt wahrscheinlich zur Anhebung der Samenqualität, ist jedoch in der Anwendung gewöhnungsbedürftig.

    Abstract
    In man, the temperature in the testis is normally several degrees centigrade lower than the body core temperature, and this is essential for unimpaired spermatogenesis.Reduced semen quality may result from scrotal heating due to regular hot baths at temperatures up to 47°C.However, there are no data proving the induction of azoospermia in humans in such conditions. It is well documented that high fever for several days can cause genital heat stress with subsequent impairment of semen quality. In contrast,adequate data on the relevance of occupational heat exposure are not available.The studies that have been conducted and published have given conflicting results in the best examined professional group, i.e.that of welders. The relevance of reduced perigenital air circulation due to insulating clothing and/or long phases of sitting each day is also a matter of debate;however, methodically reliable studies have found evidence for reduced semen quality.The examination of single factors, such as the time spent driving a car, appears to have no point unless other, similar factors, such as sitting in an office or at home, are also considered.The reduction of perigenital air circulation by means of insulating supports with contraceptive intent reduces sperm density only to 25-50% of pretreatment values.The increase of scrotal heat dissipation using cooling devices probably improves semen quality, but these devices require a high level of patient compliance.

    19. Int J Androl. 1998 Dec;21(6):358-63

    Effects of sauna on sperm movement characteristics of normal men measured by computer-assisted sperm analysis.

    Auteurs: Saikhun J, Kitiyanant Y, Vanadurongwan V, Pavasuthipaisit K.

    Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.

    The effects of sauna exposure on sperm movement characteristics and other semen parameters were evaluated using computer-assisted sperm analysis (CASA). A significant (p < 0.01) decrease in average path velocity (VAP), curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH) was found after exposure to sauna for 2 weeks. The altered parameters returned to their original values within 1 week after cessation of sauna exposure. Mean values for semen volume, sperm count, percentage motility, sperm morphology and sperm penetration assay (SPA) were not statistically different during and after sauna, when compared to the corresponding control values. The results suggest that increasing scrotal temperature by sauna causes a reversible decrease in sperm movement parameters.

    20. Reprod Biol Endocrinol. 2007; 5: 15. Published online 2007 April 20. doi: 10.1186/1477-7827-5-15.

    Lifestyle impact and the biology of the human scrotum

    Auteur: Richard Ivell

    The possession of a scrotum to contain the male gonads is a characteristic feature of almost all mammals, and appears to have evolved to allow the testes and epididymis to be exposed to a temperature a few degrees below that of core body temperature. Analysis of cryptorchid patients, and those with varicocele suggest that mild scrotal warming can be detrimental to sperm production, partly by effects on the stem cell population, and partly by effects on later stages of spermatogenesis and sperm maturation. Recent studies on the effects of clothing and lifestyle emphasize that these can also lead to chronically elevated scrotal temperatures. In particular, the wearing of nappies by infants is a cause for concern in this regard. Together all of the evidence indirectly supports the view that lifestyle factors in addition to other genetic and environmental influences could be contributing to the secular trend in declining male reproductive parameters. The challenge will be to provide relevant and targeted experimental results to support or refute the currently circumstantial evidence.

    21. International Journal of Andrology Volume 29 Issue 4 Page 446-457, August 2006

    Changes in the scrotal temperature of subjects in a sedentary posture over a heated floor

    Auteurs: Gook-Sup Song* and Ju Tae Seo†

    *Department of Architecture, Bucheon College, Geongki-Do 421-735, and †Department of Urology, Samsung Cheil Hospital, Sungkyunkwan University School of Medicine, Seoul, 100-380, Republic of Korea

    Abstract
    As Koreans habitually sit on the heated floor in their residential buildings, the male testis is directly exposed, and is therefore affected by the floor surface temperature. The purpose of this study was to investigate the changes in the scrotal temperature of the subjects in a sedentary posture over the heated floor. A rigid screening test was performed to select healthy subjects. Finally, six college students volunteered to participate in the experiments. Two experiments were performed in a controlled environmental chamber. Experiment I was designed for a low metabolism state, with the subjects reading a book in a sedentary posture for 50 min. The floor surface temperature (tf) was controlled by varying the temperature of water (tw) flowing into the floor coil from 15 to 50 °C, at 5 °C intervals. Experiment I revealed that the final scrotal surface temperature was 32.27, 32.62, 33.51, 33.34, 34.14, 34.28, 34.34 and 35.04 °C at the tw 15 °C (tf 17.0 °C), 20 °C (tf 20.8 °C), 25 °C (tf 24.1 °C), 30 °C (tf 27.8 °C), 35 °C (tf 31.7 °C), 40 °C (tf 35.9 °C), 45 °C (tf 38.6 °C) and 50 °C (tf 42.2 °C), respectively. At tf 17.0 and 20.8 °C, the scrotal temperature exhibited a declining pattern and a low temperature for spermatogenesis. At tf 24.1, 27.8 and 31.7 °C, however, the thermal regulatory system of the scrotum and testis was activated appropriately. On the contrary, scrotal temperature ascended at tf 35.9, 38.6 and 42.2 °C. Of the six subjects, two subjects demonstrated scrotal temperatures above 35 °C at tf 38.6 °C and four subjects exhibited scrotal temperatures above 35 °C at tf 42.2 °C. Experiment II was designed for a high metabolism state, with the subjects playing a card game in a sedentary posture for 180 min. The tf was controlled by varying the tw from 30 to 40 °C, at 5 °C intervals. Experiment II revealed that the final scrotal temperature was 33.43, 34.78 and 35.61 °C, and the difference between the initial and final scrotal temperatures was +0.34, +1.06 and +2.24 °C, at tw 30 °C (tf 27.8 °C), 35 °C (tf 31.7 °C) and tw 40 °C (tf 35.9 °C), respectively. The scrotal temperature was affected by the floor surface temperature and by the rate of metabolism of the subject in a sedentary posture. As derived from regression analysis, the recommended surface temperature of a heated floor is within 23–33 °C under the assumption that scrotal and consecutively testicular temperature above 35 °C impairs spermatogenesis.

    22. Int. braz j urol. vol.33 no.1 Rio de Janeiro Jan./Feb. 2007 CLINICAL UROLOGY

    Wet heat exposure: a potentially reversible cause of low semen quality in infertile men

    Auteurs: Shai ShefiI; Phiroz E. TaraporeI; Thomas J. WalshI; Mary CroughanII,III; Paul J. TurekI,II

    IDepartment of Urology, University of California San Francisco, San Francisco, California, USA
    IIDepartments of Obstetrics, Gynecology and Reproductive Science, University of California San Francisco, San Francisco, California, USA
    IIIDepartments of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA

    ABSTRACT
    OBJECTIVE: To evaluate the recovery of semen quality in a cohort of infertile men after known hyperthermic exposure to hot tubs, hot baths or whirlpool baths.
    MATERIALS AND METHODS: A consecutive cohort of infertile men had a history remarkable for wet heat exposure in the forms of hot tubs, Jacuzzi or hot baths. Clinical characteristics and exposure parameters were assessed before exposure was discontinued, and semen parameters analyzed before and after discontinuation of hyperthermic exposure. A significant seminal response to withdrawal of hyperthermia was defined as > 200% increase in the total motile sperm count (TMC = volume x concentration x motile fraction) during follow-up after cessation of wet heat exposure. RESULTS: Eleven infertile men (mean age 36.5 years, range 31-44) exposed to hyperthermia were evaluated pre and post-exposure. Five patients (45%) responded favorably to cessation of heat exposure and had a mean increase in total motile sperm counts of 491%. This increase was largely the result of a statistically significant increase in sperm motility from a mean of 12% at baseline to 34% post-intervention (p = 0.02). Among non-responders, a smoking history revealed a mean of 5.6 pack-years, compared to 0.11 pack-years among responders. The prevalence of varicoceles was similar in both cohorts. CONCLUSIONS: The toxic effect of hyperthermia on semen quality may be reversible in some infertile men. We observed that the seminal response to exposure elimination varies biologically among individuals and can be profound in magnitude. Among non-responders, other risk factors that could explain a lack of response to elimination of hyperthermia should be considered.
    Key words: male infertility; induced hyperthermia; semen; analysis; spermatogenesis

    23. Journal of Andrology, Vol. 28, No. 1, January/February 2007 Copyright © American Society of Andrology DOI: 10.2164/jandrol.106.000646

    Effect of Posture and Clothing on Scrotal Temperature in Fertile Men

    Auteurs: ROGER MIEUSSET, BOURRAS BENGOUDIFA AND LOUIS BUJAN

    From the Human Fertility Research Group, Université Toulouse III – Paul Sabatier, Toulouse, France. Correspondence to: Dr Roger Mieusset, Groupe de Recherche en Fertilité Humaine, EA 3694, Hôpital Paule de Viguier, 330, avenue de Grande-Bretagne, TSA 70034, Toulouse Cedex 9, France (e-mail: mieusset.r@chu-toulouse.fr).

    Investigation of the effects of body position and clothing on the temperature of the scrotum has given discordant results. The aim of the present study was to evaluate these effects in 13 fertile male volunteers in successive positions each held for 15 minutes, either Supine, Standing, Seated with legs apart, and Seated with legs crossed (n = 8) or Standing, Seated with legs crossed, and Standing (n = 5), at first naked and then clothed. The Standing naked position was that in which scrotal temperature reached the lowest point. Clothing increased the scrotal temperature compared with the naked state, whatever the position. The Seated with legs crossed position had specific characteristics: in the naked state, it was thermogenic and increased scrotal temperature as much as clothing in the Supine or Standing positions; in the clothed state, the increase in temperature was less than expected, which could indicate that local mechanisms are involved. Moreover, the Seated with legs crossed position had a persisting effect on scrotal temperature in the next position. These results have both pathophysiological and epidemiological implications.

    Key words: Scrotum, testis, human, thermoregulation

    24. Fertil Steril. 2007 Oct;88(4):970.e1-7. Epub 2007 Apr 16.

    High risk of temporary alteration of semen parameters after recent acute febrile illness.

    Auteurs: Sergerie M, Mieusset R, Croute F, Daudin M, Bujan L.

    Human Fertility Research Group, Université Toulouse III Paul Sabatier (EA 3694), Toulouse, France; CECOS Midi-Pyrenees, CHU Paule de Viguier, Toulouse, France.

    OBJECTIVE: To report parameters in semen samples and sperm deoxyribonucleic acid integrity in a fertile volunteer presenting a 2-day fever of 39 degrees -40 degrees C. DESIGN: Case report. SETTING: University-affiliated teaching hospital. INTERVENTION(S): None. PATIENT(S): Semen samples from a fertile volunteer of proven fertility were obtained and analyzed before the febrile illness episode and at days 15, 37, 58, 79, and >180 after the fever. MAIN OUTCOME MEASURE(S): Semen parameters (total sperm count, motility a+b, and vitality), sperm protamination state, measured by sperm chromatin structure assay (SCSA) and apoptotic activities, measured by terminal uridine nick-end labeling (TUNEL) assay. RESULTS: Total sperm count significantly decreased at days 15, 37, and 58 after the fever and returned to normal by day 79 after the fever. The percentage of motility significantly decreased at days 15 and 37 after the fever and returned to normal by day 58. Vitality score also showed a slight, although not statistically significant, decrease after the fever. The DNA fragmentation index (DFI, a SCSA parameter), which defines abnormal chromatin structure, significantly increased by 24% and 36% at days 15 and 37 after the fever, respectively, and decreased to 15% and 8% when reaching days 58 and 79 after the fever. High DNA stainability (HDS, a SCSA parameter) also significantly increased at day 37 after the fever. On the other hand, sperm DNA fragmentation, as measured by TUNEL assay, increased up to 23% by day 15 after the fever but this was not statistically significant. CONCLUSION(S): This report demonstrates that a febrile episode can have marked effects on semen parameters and sperm DNA integrity. These results are particularly important for the counseling of infertile couples and in relation to assisted reproductive techniques (ART). -->

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