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Biomedical subjects

R Mieusset

Publications and source records attributed to R Mieusset.

At least 37 records · Page 2Linked to original sources
PubMed1995

Clinical and biological characteristics of infertile men with a history of cryptorchidism.

Out of 85 fertile and 1014 infertile men, two (2.4%) and 95 (9.4%) respectively had a history of cryptorchidism. Thus cryptorchidism appears to be a risk factor for fertility since this difference was significant. Further comparisons showed that the volume of a former cryptorchid testis was smaller than the contralateral normally descended one and that sperm output/concentration was more impaired in bilateral than in unilateral cryptorchidism. A retractile testis, defined as a testis reported by the patient to be spontaneously and regularly, i.e. at least once a week, ascending up into a supra-scrotal position, was more frequent in infertile men with a history of cryptorchidism than in fertile men. Retractility was more frequent on the cryptorchid side, and was found more frequently after hormonal than after surgical treatment. Independently of all epidemiological and clinical parameters studied, retractility was associated with a lower sperm output. Among the infertile men with a history of cryptorchidism, 45% had an abnormally high scrotal temperature. This abnormal temperature represented a pejorative risk factor for fertility in this group, since it was associated with a more severely impaired spermatogenesis and a higher incidence of primary infertility than in infertile men with a history of cryptorchidism but normal scrotal temperatures.

Adult↗
PubMed1995

[Male contraception by hyperthermia].

Assessment of the contraceptive efficacy of a daily mild increase (1 degree C to 2 degree C) in testicular temperature during waking hours is reported in nine couples using two techniques of immobilization of the testes in a supra-scrotal position (close to the inguinal canal). With technique 1 (3 couples and 42 cycles), immobilization was achieved with a specific underwear; there was one undesired pregnancy from a man who stopped the heating for 3 weeks. With technique 2 (6 couples and 117 cycles), immobilization was achieved by adding a supplementary ring to the specific underwear; there was no pregnancy. Reversibility and safety were evaluated. These results suggest that a daily mild increase in testis temperature could be a potential contraceptive method for men.

Adult↗
PubMed1994

The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men.

A preliminary assessment of the contraceptive efficacy of a daily mild increase (1-2 degrees C) in testicular temperature during waking hours is reported in nine couples using two techniques of non-surgical fixation of the testes close to the inguinal canal. With technique 1, immobilization was achieved by passing the penis and the empty scrotum through a hole made in close-fitting underwear; there was one pregnancy, from a man who stopped the heating after 7 weeks, for 42 cycles of exposure in three couples. With technique 2, immobilization was achieved by adding a ring of soft material surrounding the hole in the underwear; there was no pregnancy for 117 cycles of exposure in six couples. Reversibility and safety were assessed. These preliminary results suggest that a daily mild increase in testicular temperature could be a potential contraceptive method for men.

Adult↗
PubMed1993

Increase in testicular temperature in case of cryptorchidism in boys.

Temperature of the undescended testis, measured in its cryptorchid location during surgical procedure for orchidopexy in 46 boys, 13- to 180-months-old, was significantly higher (34.4 +/- 0.9 degrees C) than that of the contralateral normally descended testicle (33.2 +/- 1.2 degrees C; P < 0.001). Temperature significantly declined from the Bogros' space (35.3 +/- 0.5 degrees C) to the inguinal canal (34.7 +/- 0.7 degrees C) and from the latter to the empty scrotal cavity (31.1 +/- 1.8 degrees C). The physiological descent of the testicle is associated with a marked cooling of its thermal environment. When this process is interrupted for any reason, temperature of the cryptorchid testis is significantly increased. This rise in temperature could be either a concomitant or a main factor for the impairement of testicular functions associated with cryptorchidism.

Body Temperature↗
PubMed1993

Influence of sperm parameters on embryo quality.

OBJECTIVE: To evaluate the influence of sperm defects on embryo quality. DESIGN: Retrospective study. SETTING: In vitro fertilization center. PATIENTS: Embryo transfers (710) from IVF attempts for tubal disease (626) or male infertility (84). MAIN OUTCOME MEASURES: Embryo morphology as a function of causes of infertility, semen, and follicular growth parameters. Embryos were classified into three groups according to their morphology. RESULTS: Transfers of embryos with good morphology were associated to a higher pregnancy rate (34%) than those with intermediate (24%) and poor (10%) morphology. Transfers of embryos with a poor morphology were more frequent (26 of 84 versus 114 of 626) and those with a fair aspect were less frequent (24 of 84 versus 229 of 626) in male infertility than in tubal disease. Embryos with a poor morphology were associated with lower percentage of morphologically normal sperms (62% +/- 19% versus 67% +/- 18%; means +/- SD) and a higher percentage of abnormalities of the postacrosomial region (29% +/- 15% versus 18% +/- 7%). Moreover, sperms with counts < 10 x 10(6)/mL were associated with a lower percentage of embryos with good morphology (18% versus 37%) than sperms with counts > or = 10 x 10(6)/mL. CONCLUSION: Embryo quality is influenced by the semen quality and especially by sperm head abnormalities, suggesting an important role of the male gamete on the early stages of embryogenesis.

Adult↗
PubMed1993

Increased oestradiol level in seminal plasma in infertile men.

Seminal hormonal patterns in fertile and infertile men were investigated. Follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, testosterone and oestradiol were assessed by radioimmunoassay, and dehydroepiandrosterone sulphate (DHAS) by bioluminescence assay, on blood and seminal plasma of 23 fertile men and 83 infertile men. For fertile men, mean FSH, LH, testosterone and DHAS concentrations were lower and mean oestradiol was higher in seminal than in blood plasma; prolactin did not differ. For infertile men, mean seminal FSH and LH showed a moderate but significant increase compared with fertile men; testosterone, DHAS and prolactin did not differ but mean seminal oestradiol was significantly increased. Of the infertile men, 53% had seminal oestradiol concentration above the 90th percentile value for fertile men. The meaning of this seminal oestradiol increase is unclear since it is not known whether it is the cause or the consequence of the alteration of spermatogenesis in infertile men. Further studies are required to explore the possible therapeutic implications.

Dehydroepiandrosterone↗
PubMed1992

Effects of heating the testes and epididymides of rams by scrotal insulation on fertility and embryonic mortality in ewes inseminated with frozen semen.

Fertilization rate and embryonic mortality were assessed in 636 ewes inseminated in each uterine horn with 50 x 10(6) frozen spermatozoa from four control rams and from four rams submitted to a moderate (1.4-2.2 degrees C), but repeated, intermittent (16 h/day for 21 consecutive days) increase in their subcutaneous scrotal temperature by means of scrotal insulation. Pregnancy was assessed twice in each ewe from concentration of progesterone in blood plasma at 17 days and by ultrasound at 65 days after insemination. No differences were observed in the pregnancy rate at 17 days between ewes inseminated with semen collected from control rams (56.0, 65.2, 66.7 and 60.3%) and from heated rams (60.6, 71.8, 63.6 and 48.2%) before or after 4, 15 and 21 days of heating, respectively. In contrast, the rate of embryonic mortality between 17 and 65 days after insemination was significantly higher at days 4, 15 and 21 in the heated rams (78.7, 78.6 and 93%) than in the control rams (55, 59 and 65.7%). These results indicate that an intermittent slight, but repeated, increase in the subcutaneous scrotal temperature could induce a significant increase in the embryonic mortality rate. As these changes were apparent on day 4 of heating, an effect must have occurred on sperm stored in the epididymis.

Animals↗
PubMed1992

Increased flow of testicular blood plasma during local heating of the testes of rams.

After removal of the scrotal skin, one testis of each of 12 adult anaesthetized rams was kept at 33 degrees C for 60 min, then heated either to 36 degrees C for 60 min and then to 39 degrees C for 60 min, or to 36 degrees C for 120 min and then returned to 33 degrees C for 100 min, while the other testis was maintained at 33 degrees C. Flow of testicular blood plasma was measured every 10 min using the technique of dilution of sodium p-aminohippurate. When the temperature of the testis was raised to 36 degrees C, flow of blood plasma gradually increased and reached a higher than normal rate at the end of the first hour, without any further increase during the second hour. The increase in mean flow rate was 25.8 +/- 3.4% (mean +/- SEM) during the second hour at 36 degrees C, and 77.1 +/- 12.8% during the hour at 39 degrees C, compared with the respective values at 33 degrees C. No significant changes were seen in testicular lymph flow determined by collection for 10 min in four rams at 36 degrees C (60 min) and then at 39 degrees C (60 min). These results are different from those from earlier studies in which total blood flow was unchanged when the scrotum and testes were heated. The difference could be related either to lack of heating of the scrotum or to the lower temperatures used in the present study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Testicular size in infertile men: relationship to semen characteristics and hormonal blood levels.

Testicular volume was assessed in 1029 infertile men and found to be normal in 704; 71 patients had unilateral and 213 had bilateral testicular hypotrophy; 4 had unilateral and 37 had bilateral atrophy. Sperm count and motility decreased in accordance with testicular volume. The lowest mean sperm counts and lowest mean motility percentages were found in patients with bilateral testicular atrophy. An increase in mean FSH and LH was also significantly linked to decreasing testicular volume; the increase in the former was not related to a drop in sperm count. A significant correlation was found between testicular volume and spermatogenesis and testicular volume is considered to be a reliable indicator of testicular function.

Follicle Stimulating Hormone↗
PubMed1989

Increased levels of serum follicle-stimulating hormone and luteinizing hormone associated with intrinsic testicular hyperthermia in oligospermic infertile men.

A Negative correlation between spermatozoa output and serum gonadotropin levels, as well as between scrotal temperature and spermatozoa output, has been found in man. However, no studies have been done on the relationship between scrotal temperature and serum gonadotropin levels. This paper reports such data from 212 infertile men. The upper limit for normal scrotal temperature was defined as the 90th percentile value (35.3 C) of a control group of 64 fertile men whose mean serum FSH and LH levels were 6.0 +/- 0.8 (+/- SE) and 6.4 +/- 0.7 IU/L, respectively. This value for scrotal temperature (35.3 C) was used to classify infertile men into 3 groups: bilateral hyperthermia (n = 56), unilateral hyperthermia (n = 40), and bilateral normothermia (n = 116). In the unilateral and bilateral hyperthermic groups serum LH and FSH levels were significantly increased compared with those in the normothermic group. The mean serum testosterone values were similar in all groups. To study the relationships between serum gonadotropin levels or spermatozoa output and scrotal temperature, the infertile men also were divided into classes according to their spermatozoa output. These classes were subdivided into two groups, normothermic or hyperthermic, according to whether the left scrotal temperature was equal to or less than, or more than 35.3 C. For the infertile men whose spermatozoa output was more than 60 X 10(6) spermatozoa/ejaculate (normospermia), there was no significant difference between the serum gonadotropin levels of the normothermic (n = 42) and the hyperthermic (n = 20) groups. Among the oligospermic men (spermatozoa output, 0.1-60 X 10(6) spermatozoa/ejaculate), the hyperthermic group (n = 65) had significantly higher serum gonadotropin levels and significantly smaller testicular volumes than the normothermic group (n = 71). The two oligospermic groups also had significantly higher serum FSH values than the infertile normospermic groups. These results were not linked to the presence of a varicocele or a history of cryptorchidism, as the prevalence of varicocele and cryptorchidism was equally distributed within the groups studied. We conclude that the increase in serum gonadotropin levels in the case of a decrease in spermatozoa output is significantly greater in the presence of associated scrotal hyperthermia.

Adult↗