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D Le Lannou

Publications and source records attributed to D Le Lannou.

At least 19 recordsLinked to original sources
PubMed2006

Geographic variations in probability of pregnancy in four cities of France.

BACKGROUND: Several studies have described geographic variations in human fecundability, but this phenomenon has almost exclusively been studied at an international level rather than within a given country. Our aim was to describe geographic variations in fecundability, the monthly probability of pregnancy, between four cities of France. METHODS: We conducted a cross-sectional study in four French maternity units from Toulouse, Rennes, Lyons and Paris, among partners of pregnant women. Women were asked about the time to pregnancy (TTP) of their current pregnancy. TTP was analysed with a discrete Cox model allowing to estimate fecundability ratios (FR). RESULTS: Time to pregnancy was defined for 894 couples. There was no strong evidence of heterogeneity in fecundability between the four compared cities (p=0.05 without adjustment and p=0.25 after adjustment for behavioural and medical factors). The highest fecundability was observed in Rennes and the lowest in Toulouse (fecundability ratio (FR)=1.28, 95% CI: 1.01-1.63). Differences in fecundability were smaller between the other cities. CONCLUSION: We highlighted a possibly slightly higher fecundability in Rennes compared to Toulouse. Possible explanations for this finding are discussed. We note that the finding is consistent with previous observations indicating a higher sperm concentration among semen donors in Rennes than in Toulouse.

Cross-Sectional Studies↗
PubMed2004

Selection bias in semen studies due to self-selection of volunteers.

BACKGROUND: Reports of a secular decrease in semen quality remain controversial, particularly due to the possibility of selection bias. We aimed to describe the potential bias due to self-selection of volunteers in semen studies involving fecund men. METHODS: Using data from the French multicentre study REPRHOM, we compared the characteristics of the partners of pregnant women for three levels of participation: completion of a refusal questionnaire (n = 698), agreement to complete the study questionnaires only (n = 676) and agreement to complete the study questionnaires and give a semen sample (n = 331, 13% of the subjects approached). RESULTS: Poorly educated men refused more often to participate than highly educated men. Semen providers were more likely to have experienced unfavourable pregnancy outcomes (odds ratio 1.68, 95% confidence interval 1.14-2.49) compared with participants completing the questionnaires only. Time to pregnancy was similar for all participants. CONCLUSIONS: This study demonstrates the existence of selection bias in semen studies associated with fertility and socio-demographic characteristics of men. The results of semen analysis for this population sample cannot be extrapolated to the whole population from which the volunteers originate. More information is required on who participates, and participation rates should be reported in semen studies to make it possible to interpret the results correctly.

Adult↗
PubMed2004

[Artificial insemination with donor frozen sperm].

The cryopreservation of human sperm decreases its fecondity, by reduction in the number of motile sperm. However the fertilizing ability of the spermatozoa is not faded. The use of frozen sperm requires an optimization of the methods of artificial insemination to hope to approach the results obtained with fresh sperm. Intrauterine insemination with sperm selection meets this aim.

Cryopreservation↗
PubMed2002

[Is the limitation to 6 cycles of insemination with donor sperm justified?].

OBJECTIVE: To evaluate the effect of the limitation at 6 cycles of artificial insemination in a program of sperm donation. STUDY DESIGN: 266 couples included in a program of sperm donation underwent 1,354 cycles including 532 intracervical insemination (ICI), 678 intrauterine insemination (IUI) and 133 in vitro fertilization (IVF). RESULTS: The birth rate by cycle was 10.8% in ICI, 18% in IUI, 21.9% in IVF. The risk of multiple pregnancies was 0% in ICI, 13% in IUI, 33% in IVF. The authors feign then two strategies, the first one with 6 ICI followed by 6 IUI, and the other one with 6 IUI alone. The birth rate, the risk of multiple pregnancies and the cost of these two strategies is discussed. CONCLUSION: The restriction to 6 IA Cycles in a donor semen program does not change the birth rate, but increases the multiple pregnancy rate and the cost of the treatment of these patients.

Female↗
PubMed2000

Molecular screening of the CFTR gene in men with anomalies of the vas deferens: identification of three novel mutations.

Many studies have shown that congenital absence of the vas deferens (CAVD) is a genital cystic fibrosis transmembrane conductance regulator (CFTR)-mediated phenotype, with a broad spectrum of abnormalities causing male infertility. The genotype of these patients includes mutations in the CFTR gene, e.g. DeltaDeltaF508, R117H and the T5 allele; all of which are commonly found in CAVD. In this study we have screened the entirety of CFTR gene in 47 males with anomalies of the vas deferens: 37 cases of congenital bilateral absence of the vas deferens, three cases of congenital unilateral absence of the vas deferens and seven cases of obstructive azoospermia with hypoplastic vas deferens. Among the 94 chromosomes studied, 65 mutations, of which three are novel (2789+2insA, L1227S, 4428insGA), were identified. The majority of patients (63.8%) had two detectable CFTR gene mutations. Furthermore, high frequencies of the DeltaDeltaF508 mutation (44.7%), the T5 allele (36.2%) and R117H mutation (19.1%) were observed.

Adult↗
PubMed1999

Influence of seminal plasma on cryopreservation of human spermatozoa in a biological material-free medium: study of normal and low-quality semen.

The objective was to evaluate the efficiency of a biological material-free medium and the role of seminal plasma (SP) in the cryopreservation of human spermatozoa. Normal semen samples and low-quality semen samples were used for this study. After centrifugation of 300 microL fractions of whole semen, pellets were resuspended either in autologous SP or in a chemically defined medium (BM) supplemented or not with 3% bovine serum albumin (BSA); after 15 min at 37 degrees C, the samples were diluted (V/V) with cryoprotective medium (30 mM NaCl; 22 mM sodium citrate, 19.4 mM fructose; 80 mM glutamine; 14%, V/V, glycerol) and maintained for 15 min at room temperature before freezing. Assessment of viability and motility was performed using fresh semen (T0), after centrifugation and resuspension prior to adding the cryoprotectant (T15), after adding the cryoprotectant (T30) and after freezing and thawing (Tpost). In all three resuspending media used, sperm viability and motility (forward and total) decreased (p < 0.05) during both the equilibration period especially before addition of the cryoprotective medium (between T0 and T15) and during the freeze-thaw process comparison between T30 and Tpost. The recovery of viable and motile spermatozoa (post-thaw values/values of fresh samples) was higher (p < 0.05) in normal semen than in low-quality semen. In both groups, the recovery was slightly, but significantly, higher with SP than with BM and the presence of BSA has no beneficial effect. To conclude, these data suggest that SP may reduce the deleterious effects of cryopreservation. Nevertheless cryopreservation of spermatozoa in a medium containing neither SP nor biological substances could offer an acceptable cryoprotection of spermatozoa to be used in assisted fertilization procedures, especially for intracytoplasmic sperm injection.

Animals↗
PubMed1999

[Microsurgical epididymal sperm aspiration (MESA), testicular biopsy and intracytoplasmic sperm injection (ICSI) in the treatment of male infertility].

OBJECTIVE: To assess if ICSI using epididymal or testicular spermatozoa is effective in the treatment of couples with male factor infertility. MATERIAL AND METHODS: 56 couples suffering from male infertility underwent a total of 88 treatment cycles of ICSI, in combination with microsurgical epididymal sperm aspiration (MESA): 62 cycles, or testicular sperm retrieval: 26 cycles. RESULTS: Overall, fertilization rate was 63% per injected metaphase II oocyte. In MESA group, fertilization rate was 64% compared to 61% embryos in testicular sperm aspiration. The overall pregnancy rate was 26% per started ICSI cycle. Pregnancy rates were also similar in both group: 24% for MESA and 32% for testicular sperm extraction. 9 pregnancy (41%) were obtained using cryopreserved epididymal sperm (6 cases) or testicular sperm (3 cases). CONCLUSION: ICSI combined with epididymal or testicular sperm achieved a high fertilization and pregnancy rate. It constitutes an efficient alternative in the treatment of men suffering of testicular failure or azoospermia not amenable to surgical reconstruction.

Adult↗
PubMed1998

Influence of oxygen tension on function of isolated spermatozoa from ejaculates of oligozoospermic patients and normozoospermic fertile donors.

Oxygen radical generation is known to be detrimental to sperm function. An example of a reactive oxygen species-associated male pathology is oligozoospermia in which fertilization and pregnancy rates are low in in-vitro fertilization (IVF) programmes. As the extent of the modifications induced by reactive oxygen species (ROS) depends on several factors, notably from oxygen tension in the incubation medium, the aim of this study was to examine the influence of a low (5%) rather than atmospheric (20%) oxygen tension in the incubator gas phase on the function of Percoll-selected spermatozoa from ejaculates of oligozoospermic patients and normozoospermic fertile donors. After incubation for several hours in a gas phase of either 5% CO2/90% N2/5% O2 or 5% CO2/95% air (20% O2), none of the parameters investigated, e.g. movement characteristics, potential of spermatozoa to acquire hyperactivated motility, to undergo the acrosome reaction when challenged with a calcium ionophore and to fuse with zona-free hamster oocytes, was significantly different between the two oxygen tensions in fertile donors. In contrast, among oligozoospermic patients, the motility parameters, the percentage of hyperactivated motility and of induced-acrosome reaction were significantly improved under a gas phase of 5% O2 compared with those observed under an atmosphere of 20% O2 (P < 0.05). Exposure to 5% rather than 20% oxygen tension also induced a significant increase in the percentage of penetration of zona-free hamster eggs after capacitation for 17 h, but no difference was found in the mean number of bound spermatozoa per oocyte. After incubation for 24 h, a significantly higher survival rate was observed under 5% compared with 20% oxygen tension. These results show that the use of a low oxygen tension rather than air might improve spermatozoan competence of oligozoospermic patients during IVF programmes.

Acrosome Reaction↗
PubMed1998

Multicentre approaches to donor insemination in the French CECOS Federation: nationwide evaluation, donor matching, screening for genetic diseases and consanguinity. Centre d'Etudes et de Conservation des Oeufs et du Sperme humain.

The French CECOS Federation collates the results of its 22 sperm banks and provides annual reports on their activity. These records allow studies on many different aspects; annual nationwide evaluation, matching of donors and recipients, follow-up of pregnancies, research into artificial procreation, and natural fertility. Risk of transmitted hereditary disease is minimised by genetic screening which establishes the genealogy of donor candidates and includes karyotyping and other biological investigations when a particular risk is suspected. The real risk of consanguinity is very small. Limiting the number of children born from a given sperm donor can be defined at the local level.

Consanguinity↗
PubMed1997

Reactive oxygen species and human spermatozoa: physiology and pathology.

The role of reactive oxygen species (ROS) in the pathophysiology of human sperm function has been emphasized in recent years. ROS production in semen has been associated with loss of sperm motility, decreased capacity for sperm-oocyte fusion and loss of fertility. There is a current presumption that the most prolific source of ROS in sperm suspensions is an NADPH oxidase located in leukocytes or in spermatozoa which produces superoxide which is further converted to peroxide by the action of superoxide dismutase. Hydrogen peroxide has been recognized as the most toxic oxidizing species for human spermatozoa, which are very sensitive to lipid peroxidation owing to the high content of polyunsaturated fatty acids in their plasma membrane, though this is not the sole mechanism by which sperm function might be impaired by ROS. Although the excessive production of ROS is detrimental to human spermatozoa, there is a growing body of evidence which suggests that ROS are also involved in the physiological control of some sperm functions. This review focuses on the nature and source of the ROS generated by human spermataozoa as well as their operational mechanisms and their effects, which may be detrimental or beneficial.

Animals↗
PubMed1997

Influence of oxygen tension on reactive oxygen species production and human sperm function.

Human spermatozoa were exposed to the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) to stimulate endogenous production of reactive oxygen species (ROS). They were incubated under a gas phase of 5% CO2/90% N2/5% O2, or 5% CO2/95% air (20% O2) to investigate whether a lower than atmospheric oxygen tension in the gas phase of the incubator limited the endogenous production of ROS by human spermatozoa and thus was able to reduce the cytotoxic effects of ROS on sperm function. Exposure of human spermatozoa or exogenous NADPH induced an 8-fold higher production of superoxide anion under ambient vs. low oxygen tension. This marked difference in the stimulation of superoxide anion generation was associated with significantly different sperm motility parameters, according to the oxygen tension in the gas phase of the incubator. Whereas under 5% oxygen the percentage of motile spermatozoa was unaffected by the presence of NADPH, all of the motility parameters recorded under an atmosphere of 5% CO2 in air were dramatically affected, not only compared to their respective controls, but also compared to the motility parameters observed under low oxygen tension. The presence of superoxide dismutase plus catalase protected spermatozoa against the toxic effects of NADPH, confirming a cause/effect relationship between the increased superoxide production and reduced sperm function. Even at a concentration of NADPH which did not alter the percentage of motile spermatozoa, hyperactivated motility and acrosome reaction were significantly lower under an atmosphere of 5% CO2 in air compared to a gas phase of 5% CO2/90% N2/5% O2. These results suggest that there is an advantage in using 5% O2 rather than 20% O2 in the gas phase of the incubator to prevent the excessive production of ROS by spermatozoa and related alterations of sperm functions. This may be of clinical value in fertilization programmes.

Dose-Response Relationship, Drug↗
PubMed1997

Enhancement of motility by treating spermatozoa with an antioxidant solution (Sperm-Fit) following ejaculation.

Oxygen radical generation is known to be detrimental to sperm function, especially motility, through the lipid peroxidation of the membranes. Generation of reactive oxygen species can be induced by leukocyte contamination, sperm centrifugation and the presence of abnormal spermatozoa with excess residual cytoplasm. This study aims to evaluate the effect on sperm motility of incubation in an antioxidant-containing solution, during liquefaction and centrifugation. Thirty semen samples were each divided into two equal parts: one mixed with Tyrode's solution, the other with a salt solution containing antioxidants (Sperm-Fit; Ellios Bio-Media, Paris, France). All the procedures were identical in the two groups. The ratio of leukocytes to spermatozoa was significantly correlated with the motility after liquefaction and after a 24 h incubation in routine in-vitro fertilization (IVF) medium and with the number of motile spermatozoa recovered after Percoll preparation. Moreover, when this ratio was > or = 0.2, all motility parameters were lowered. Incubation with Sperm-Fit allowed a higher percentage of motility after Percoll preparation when the ratio was > or = 0.2 (48 +/- 5% versus 41 +/- 6% for Sperm-Fit and Tyrode's solution respectively; P < 0.05) and a greater number of motile spermatozoa recovered after Percoll preparation, whatever the ratio (3.2 +/- 1.0 x 10(6) versus 2.4 +/- 0.7 x 10(6) for Sperm-Fit and Tyrode's solution respectively when ratio > or = 0.2; 18.1 +/- 3.4 x 10(6) versus 14.4 +/- 2.9 x 10(6) for Sperm-Fit and Tyrode's solution respectively when ratio < 0.2; P < 0.05). These results show that incubation with antioxidants during liquefaction and centrifugation increases recovery of motile spermatozoa.

Antioxidants↗
PubMed1996

Improvement of motility of post-thaw Poitou jackass sperm using glutamine.

The relative effectiveness of L-glutamine in preserving motility and movement characteristics of Poitou jackass spermatozoa diluted at 60 x 10(6) sperm/ml in INRA 82 medium modified by 4 % (v/v) glycerol and 2 % (v/v) quail's egg yolk during the cooling and freezing-thawing process was studied. After cooling to 4 degrees C, glutamine at 80, 120 or 240 mM did not improve the percentages of motile and progressively undulating spermatozoa or the movement characteristics (VCL = curvilinear velocity, VSL = straight line velocity, VAP = velocity of the average path, LIN = VSL/VCL x 100, ALH = amplitude of the lateral head displacement, BCF = beat cross frequency) assessed by the automated analyzer ATSM. However, after the FT process, 80 mM glutamine significantly improved motility, the percentage of progressively undulating spermatozoa and all the movement characteristics analyzed. The presence of glutamine at 80 mM in a glycerol-FT medium thus improves the motility of Poitou jackass spermatozoa during the freezing-thawing process. The presence of glutamine at 80 mM was not sufficient to offset the need to use glycerol in the freezing-thawing medium. This could indicate that glutamine has a mechanism of cryoprotection for Poitou jackass spermatozoa that is independant of glycerol.

Journal Article↗
PubMed1996

Improvement of motility and fertilization potential of postthaw human sperm using glutamine.

The effectiveness of three amino acids, glutamine, proline, and histidine, and one amino acid-related compound, betaine, in preserving human sperm diluted v/v in a basal medium (BM) containing 14% glycerol during the freeze-thaw (FT) process was studied. At 80 mM in BM, only glutamine improved the 5- to 60-min postthaw total and progressive motilities and velocity. The presence of glutamine at 80 mM is not sufficient to achieve lower concentrations of the toxic agent glycerol in FT medium. Glutamine may therefore have a mechanism of protection on human spermatozoa that is independent from that of glycerol. The zona-free hamster egg penetration test showed that the percentage of eggs penetrated was significantly greater when spermatozoa were frozen-thawed with 80 mM glutamine in BM. Consequently, the presence of glutamine at 80 mM in a glycerol-FT medium maintains human sperm motility and fertilizing ability during the FT process.

Animals↗
PubMed1996

[1995 evaluation of the CECOS Federation. Use of different methods of assisted reproductive techniques].

Intracervical insemination IC is still the most common method of ART with frozen donor semen. During the year 1995 in France IC was used in 63% of all cycles, with a pregnancy rate per cycle (PR) of 9.3%. Intrauterine insemination IU was used in 24% of all cycles with a PR of 13% (p < 0.01) and in vitro fertilization IVF in 12% of all cycles with a PR of 22% (p < 0.01). The benefit of the different methods, in relation with the number of unsuccessful cycles, and in relation with the quality of frozen semen is analysed.

Female↗
PubMed1995

Assessment of acrosome-reacted boar spermatozoa using monoclonal antibody GB 24 and propidium iodide.

Fluorescein-labeled GB 24, a mouse monoclonal antibody, was evaluated as an acrosomal dye for boar spermatozoa that had previously been stained with propidium iodide (PI) to assess sperm viability. A specific sperm-staining pattern with fluorescein-labeled GB 24 was shown to be associated with acrosome reaction on freshly ejaculated sperm when fixed with acetone or induced with ionophore A 23187, whereas the presence of PI staining was typical of dying spermatozoa. The GB 24-PI procedure was as accurate as the glutaraldehyde method in assessing acrosomal presence or absence on freshly ejaculated spermatozoa when spontaneous or A 23187-induced acrosomal reactions were considered. Approximately half of A 23187-induced spermatozoa with acrosomal loss did not exhibit a PI fluorescence; these were potentially viable acrosome-reacted spermatozoa. On semen diluted in a boar sperm-specific diluent (BTS-A) and stored, percentages of spermatozoa with nonintact acrosome from glutaraldehyde and GB 24-PI were not significantly different. Conversely, data from GB 24-PI was significantly lower than those from glutaraldehyde when semen were undiluted. This suggested that spermatozoa with reacted acrosome gradually lost their ability to bind with GB 24. Providing unequivocal and rapid scoring of acrosome-reacted spermatozoa, the GB 24-PI procedure may be a valuable tool in the evaluation of the acrosomal status of porcine fresh spermatozoa.

Journal Article↗