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At least 811 records · Page 45Linked to original sources
PubMed2000

Comparison of the effects of two methods of cryopreservation on testicular sperm DNA.

OBJECTIVE: To assess the effects of two methods of freezing on testicular sperm DNA from subjects with obstructive azoospermia and to compare these with samples of fresh and freeze-thawed testicular sperm from fertile men. DESIGN: The Comet assay was used to determine the percentage of undamaged DNA in fresh testicular sperm, testicular sperm freeze-thawed in suspension and in a biopsy sample (men with obstructive azoospermia), and in fresh and freeze-thawed testicular sperm (fertile men). SETTING: The Regional Fertility Center, Royal Maternity Hospital, Belfast, Northern Ireland, United Kingdom. PATIENT(S): Twelve males with obstructive azoospermia (normal testicular volume and hormone profiles) and nine fertile control subjects. INTERVENTION(S): Trucut needle testicular biopsy under local anesthetic. MAIN OUTCOME MEASURE(S): Measurement of the percentage of undamaged DNA in fresh and freeze-thawed testicular sperm using the Comet assay. RESULT(S): No significant difference was found between the percentage of undamaged DNA of fresh testicular sperm and of both types of freeze-thawed testicular sperm. There was also no significant difference between the percentage of undamaged DNA in fresh or freeze-thawed testicular sperm from controls. Control ejaculated sperm DNA was significantly more damaged than testicular sperm DNA from control men. CONCLUSION(S): Cryopreservation of testicular sperm does not increase baseline levels of DNA damage.

Biopsy↗
PubMedDate not supplied

Dual DNA staining assessment of bovine sperm viability using SYBR-14 and propidium iodide.

A new membrane-permeant DNA stain, SYBR-14, was used in combination with propidium iodide (PI) to estimate the proportion of living sperm in bovine semen. The SYBR-14 stained living sperm while PI only stained degenerate cells that had lost their membrane integrity. Staining with SYBR-14 resulted in the nuclei of living sperm fluorescing bright green. Aliquots containing nearly all living bovine sperm were prepared using glass wool/Sephadex filtration to remove dead and damaged cells. A portion of this filtered sample was killed by unprotected freeze-thawing and used to provide mixed aliquots containing known ratios of living and dead sperm. Flow cytometry was used to assess the green and red fluorescence of these mixtures. The percentages of living sperm, as determined by the log of green fluorescence, were 85.1, 68.8, 39.8, 20.7, and 1.4 for ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 of the filtered, killed mixtures. Also, bovine semen was diluted 1:60 in HEPES-0.1% bovine serum albumin and incubated for 0, 3, 6, and 24 hours at 36 degrees C to assess changes in cell viability. As cell death occurred during this incubation period, a relatively rapid transition of staining from green to red occurred as sperm died. Three replicates of cryopreserved sperm from six bulls were also examined using SYBR-14 and PI to assess the proportion of living and dead cells. Flow cytometric analyses of these samples, which had been processed and stored in homogenized milk, indicated that this stain combination was useful in assessing the quality of cryopreserved sperm. The combination of SYBR-14 and PI was determined to be an effective tool for assessing the viability of fresh or cryopreserved sperm.

Animals↗
PubMed2006

Artificial insemination in domestic cats (Felis catus).

Artificial insemination (AI) in cats represents an important technique for increasing the contribution of genetically valuable individuals in specific populations, whether they be highly pedigreed purebred cats, medically important laboratory cats or endangered non-domestic cats. Semen is collected using electrical stimulation, with an artificial vagina or from intact or excised cauda epididymis. Sperm samples can be used for AI immediately after collection, after temporary storage above 0 degrees C or after cryopreservation. There have been three and five reports on intravaginal and intrauterine insemination, respectively, and one report on tubal insemination with fresh semen. In studies using fresh semen, it was reported that conception rates of 50% or higher were obtained by intravaginal insemination with 10-50x10(6) spermatozoa, while, in another report, the conception rate was 78% after AI with 80x10(6) spermatozoa. After intrauterine insemination, conception rates following deposition of 6.2x10(6) and 8x10(6) spermatozoa were reported to be 50 and 80%, respectively. With tubal insemination, the conception rate was 43% when 4x10(6) spermatozoa were used, showing that the number of spermatozoa required to obtain a satisfactory conception rate was similar to that of cats inseminated directly into the uterus. When frozen semen was used for intravaginal insemination the conception rate was rather low, but intrauterine insemination with 50x10(6) frozen/thawed spermatozoa resulted in a conception rate of 57%. Furthermore, in one report, conception was obtained by intrauterine insemination of frozen epididymal spermatozoa. Overall, there have been few reports on artificial insemination in cats. The results obtained to date show considerable variation, both within and among laboratories depending upon the type and number of spermatozoa used and the site of sperm deposition. Undoubtedly, future studies will identify the major factors required to consistently obtain reliable conception rates, so that AI can become a practical technique for enhancing the production of desirable genotypes, both for laboratory and conservation purposes.

Animals↗
PubMed2002

Processing of ovine cardiac valve allografts: 3. Implantation following antimicrobial treatment and preservation.

It is known that a satisfactory clinical outcome can follow the implantation of cardiac valve allografts in spite of the loss of living cells in the tissue. If viable cells are not required for long term graft function, then effective disinfection of the tissue might become possible. In an earlier paper in this series we reported that peracetic acid (PAA) is an effective antimicrobial agent for the treatment of valve allografts; it was lethal to the cells but at a concentration of 0.21% had little effect on the mechanical properties or extracellular morphology of the valve leaflets. It was also found that PAA-treatment could be combined with storage in 85% glycerol at 4 degrees C, or cryopreservation with 10% Me(2)SO, without substantial further impairment of microscopic structure or mechanical properties. In this paper we describe the implantation of processed ovine aortic valves in the descending thoracic aorta of sheep. The experimental groups included control untreated valves and valves that had been treated with antibiotics or PAA and either cryopreserved, or stored in 85% glycerol. The recipient sheep showed good clinical appearances until the experiment was terminated at six months. The explanted grafts were examined by standard morphological and mechanical testing methods. The PAA-treated valves were clearly recognisable as valves: the leaflets had fair to medium morphology in both the unpreserved and the cryopreserved groups. All leaflets had a superficial overgrowth of cells. Microsatellite analysis for allelic differences were performed on samples of donor and recipient tissues using three markers of tissue source. Only one valve, which had been treated with PAA, revealed allelic differences between donor and recipient. It is suggested that DNA-fragments may have remained after the destruction of donor cells and six months of implantation: the overgrowing cells were almost certainly of recipient origin. We conclude that our experiments, in which PAA-treatment was combined with preservation, are sufficiently encouraging to justify further studies to refine the technique, but in our opinion they are not sufficient to justify a clinical trial at this time.

Journal Article↗
PubMed1998

Successful treatment of idiopathic anejaculation with electroejaculation after microsurgical vas aspiration.

This case report describes a couple suffering from infertility secondary to psychogenic anejaculation, which was refractory to all conservative treatment modalities. A first trial of microsurgical vas aspiration in combination with in-vitro fertilization (IVF) resulted in a pregnancy. After 2 years, three more trials of microsurgical vas aspiration in combination with either IVF or subzonal insemination (SUZI) resulted in embryo transfer without pregnancy. Finally, after 3 years, spermatozoa obtained by rectal probe stimulation under general anaesthesia were cryopreserved. A second intracytoplasmic sperm injection (ICSI) procedure using these cryopreserved spermatozoa also resulted in a second pregnancy. Although sperm concentration was in the normal range, in all samples obtained by either rectal probe electrostimulation or microsurgical vas aspiration, motility was <30% in all but two samples.

Adult↗
PubMed1981

Measurement of near-normal concentrations of erythrocyte protoporphyrin with the hematofluorometer: influence of plasma on "front-surface illumination" assay.

Zinc protoporphyrin in erythrocytes increases in iron depletion. Because the hematofluorometer directly measures zinc protoporphyrin in whole blood, it may therefore be a useful screening instrument for detecting iron deficiency. We evaluated its performance with normal to slightly above-normal zinc protoporphyrin concentrations (0.2 to 2.0 mg/L) in erythrocytes, because this is a critical range for differentiating normal and iron-deficient individuals. There was excellent correlation (r2 = 0.900) between erythrocyte protoporphyrin as measured by an extraction procedure and as measured directly with the hematofluorometer. However, at these concentrations, plasma caused hematofluorometer readings to be spuriously high, by 2.4 to 89.4%, an effect due to the instrument's optical design. The effect can be eliminated by washing the cells free of plasma or by allowing erythrocytes to displace plasma by settling to the illuminated surface before the measurement. The interference does not affect the hematofluorometer's sensitivity, but abnormal results obtained for whole blood should be confirmed with more-specific tests, and interlaboratory precision may be influenced if whole-blood samples are used. A 1-min delay from sample placement to measurement decreased zinc protoporphyrin values by 2.6 to 36.9%. We also describe the use of cryopreserved control erythrocytes, for which the CV is 2.3% for a concentration of 0.96 mg per liter of erythrocytes, which are not affected by time of measurement, and which are stable for three months.

Blood Chemical Analysis↗
PubMed1997

Comparative viability of bovine sperm frozen on a cryomicroscope or in straws.

The accuracy and repeatability of freezing rates and effects of evaporation were examined using a new cryomicroscope system to establish its usefulness in assessing the development of cryopreservation protocols for bovine semen. Post-thaw sperm plasma membrane integrity, as assessed by using combinations of fluorescent stains and flow cytometry, was used in evaluating protocols for freezing spermatozoa on the cryomicroscope. Semen was diluted in Test-yolk (20%) extender containing 7% glycerol and frozen in 0.5-ml straws, 0.25-ml straws (over liquid nitrogen for 8 min) or in a quartz crucible using a Linkam BCS 196 cryomicroscope. Thawed samples were diluted with Hepes buffered medium containing 0.1% bovine serum albumin (BSA) and stained with either carboxymethylfluorescein diacetate (CMFDA) or SYBR-14 each in combination with propidium iodide (PI). Flow cytometry analysis of the samples revealed 2 major populations: 1) spermatozoa with intense green fluorescence (stained with CMFDA or SYBR-14), which were classified as plasma membrane-intact and 2) spermatozoa with intense red fluorescence, (stained with PI), which were classified as plasma membrane-damaged. Samples frozen using the cryomicroscope contained 29 and 26 % plasma membrane-intact (PMI) sperm cells, as assessed by CMFDA and SYBR-14, respectively. Cryopreservation of spermatozoa in 0.5-ml straws resulted in 22 and 20% plasma membrane- intact sperm cells, while spermatozoa frozen in 0.25-ml straws resulted in 34 and 31% PMI sperm cells for CMFDA and SYBR-14, respectively. No significant difference was observed (P > 0.05) for PMI spermatozoa stained with either CMFDA or SYBR-14. In addition, the ability to recover spermatozoa after freezing on the cryomicroscope establishes the Linkam BCS 196 as a useful tool for the study of sperm cell cryopreservation.

Journal Article↗
PubMed1996

[Lipid peroxidation and hemolysis in HES cryopreserved erythrocytes].

Using malondialdehyde (MDH) as an indicator of lipid peroxidation it was examined, whether oxygen radicals could be an origin of freeze-induced weakness of HES-cryopreserved erythrocytes. Each of 11 erythrocyte suspensions (Hct = 40; HES 200,000/0.62/12.5%; 60 mmol NaCl) was separated into 40 ml samples, cooled down to -196 degrees C und stored at -80 degrees C, finally. Samples were thawed after 1, 2, 3 und 6 months storage and besides that, one sample having remained at -196 degrees C (LN2). The MDH content (1.5 mumol/l Ery unwashed; 0.4 mumol/l Ery washed) amounted to 3.4 mumol/l Ery after LN2 storage, to 4 mumol/l Ery after 1 und to 8 mumol/l Ery after 6 months at -80 degrees C. Similarly, the MDH generation rate at -80 degrees C increased with storage time. The membrane fragility (1 in freshly drawn erythrocytes; 1.3 in erythrocytes out of LN2) rose from 1.6 after 1 month to 2.4 after 6 months. MDH content and membrane fragility were correlated linearly (r = 0.98). It is concluded that increased superoxide formation is mediated by freezed-induced oxidation of Hb-bound Fe. This allows peroxidation of membrane lipids which in consequence causes hemolysis.

Blood Preservation↗
PubMed2006

Measurement of light transmittance of cryopreserved human amniotic membrane.

PURPOSE: To measure the light transmission of human amniotic membrane (AM) and compare it with that of therapeutic soft contact lens (TSCL). METHODS: Total light transmittance of each sample (4 AMs and 2 TSCLs) was measured in the 250- to 800-nm range by using a spectrophotometer. RESULTS: The percent light transmission of TSCL was nearly 100% at wavelengths greater than 450 nm, decreased gradually in the sub-450-nm range, and reached 78.4 +/- 3.7 at 250 nm. In contrast, the percent transmission of the 4 AMs decreased gradually and continually throughout the spectrum as wavelength shortened. The transmission of light through AM dropped to less than 20% at 250 nm but remained 90% or more at wavelengths more than 600 nm. CONCLUSION: Light transmittance properties of cryopreserved human AM and human cornea are relatively similar, but AM (and not cornea) allows transmission of 24.6% of UVC.

Amnion↗
PubMed2003

Cryopreservation of cord blood after liquid storage.

BACKGROUND: The processing of cord blood may result in delays prior to RBC depletion and cryopreservation. The overall objective of this investigation is to determine the influence of liquid storage prior to cryopreservation on the post-thaw viability. METHODS: UC blood supplemented with CPD anticoagulant (CB) was obtained from normal donors with informed consent. CB was stored undiluted, or diluted with 1:1 ratio of storage solution STM-sav for up to 72 h. The undiluted control samples were stored at room temperature. CB samples supplemented with STM-sav were stored at 4 degrees C. After completion of the storage protocol, the sample was RBC depleted, frozen, stored, thawed, and assayed for viability. Nucleated cell counts, percentage of CD34+ cells, and frequency of colony formation were determined during liquid storage and after cryopreservation. RESULTS: The post-thaw mononuclear cell recovery and viability of cord blood stored for 72 h was significantly lower than that of cord blood stored for 24 h prior to cryopreservation. This difference was true for cord bloods stored in STM-sav and controls. Dilution of the cord blood with STM-sav improved the frequency of CFU-GM observed. DISCUSSION: Liquid storage of cord blood for 24 h prior to cryopreservation does not adversely influence the post-thaw cell recovery. The use of a storage solution (STM-Sav) enhances the retention of colony-forming capabilities post-thaw. These and other studies provide an important foundation for the development of integrated protocols for cord blood banking.

Antigens, CD34↗
PubMedDate not supplied

Reliability of urinary 6-sulfatoxymelatonin as a biomarker in breast cancer.

The objective of this study is to evaluate the effect of cryopreservation at different storage temperatures on urinary 6-sulfatoxymelatonin (aMT6s) concentration. Overnight urine from 28 postmenopausal women participating in the ORDET cohort study was filtered and separated into 6 mL aliquots. Urine samples were stored at -80 degrees C and at -30 degrees C for an average of 14 years. Urinary aMT6s concentration was assessed using a competitive immunoassay. Mean aMT6s values of samples stored at -30 degrees C were systematically lower than those of samples stored at -80 degrees C (10.7 ng/mL versus 15.8 ng/mL, p<0.001). Bland Altman plots showed disagreement between determinations at different storage temperatures at the highest levels of the metabolite concentration. The degree of agreement evaluated in terms of intraclass correlation coefficient was 0.68 (95% CI 0.41-0.84, p<0.0001). Pearson's correlation coefficient between aMT6s values of the two differently stored samples was 0.93 (p<0.001), while the Kendal tau coefficient for rank distribution was 0.73 (p<0.001). Our data suggest that storage temperatures might affect degradation of aMT6s during storage. However, individual characterization by melatonin levels does not seem to be affected by cryopreservation conditions.

Adult↗
PubMed2000

Testicular tissue cryopreservation in boys. Ethical and legal issues: case report.

Sperm preservation prior to chemotherapy and radiotherapy is common practice in adult males. Spermatozoa are usually retrieved from an ejaculated sample although there are occasions when testicular tissue is used as the source. These techniques of sperm preservation present minimal ethical objections as the patients give their informed consent. Sperm preservation in children presents practical and ethical dilemmas in that the children cannot always give their informed consent, there are no regulatory guidelines and there is no guarantee that spermatogenesis is occurring. With the rapid advances in reproductive technology and the possible future use of immature germ cells by in-vitro maturation or transplantation, the demand for immature testicular tissue preservation is likely to increase. More information for the parents and oncologists with regard to this subject is needed to allow informed decisions to be made on behalf of the children. These issues are discussed using two cases of children having testicular tissue preservation.

Adolescent↗
PubMed2001

Validation of a reverse transcription nested polymerase chain reaction (RT-nPCR) to detect bovine viral diarrhea virus (BVDV) associated with in vitro-derived bovine embryos and co-cultured cells.

Sensitive RT-nPCR assays can be used for the rapid detection of viruses. The objective of this research was to validate an RT-nPCR assay for detection of BVDV associated with various samples collected from an IVF system. In 12 research replicates, we maintained matured COCs as negative controls or exposed them to 1 of 4 noncytopathic strains (SD-1, NY-1, CD-87, or PA-131) of BVDV for 1 h immediately before IVF. After 4 d of IVC, we harvested groups of 5 nonfertile ova or degenerated embryos (NFD) and some associated cumulus cells and transferred developing embryos and the remaining cumulus cells into secondary IVC drops. On the seventh d of IVC, cumulus cells, groups of 5 washed NFD and groups of 5 developed, washed embryos were harvested. We also collected single developed embryos after washing, washing with trypsin, washing and cryopreservation in ethylene glycol, or washing with trypsin and cryopreservation in ethylene glycol. All washes were performed according to International Embryo Transfer Society standards. Developed embryos and NFD were sonicated prior to assay. All samples were assayed for BVDV using virus isolation and RT-nPCR. The virus isolation and RT-nPCR assays determined that all negative control samples were BVDV-free. Virus was detected in association with all exposed cumulus cells and groups of developed embryos using both virus isolation and RT-nPCR. Results from viral assays of other exposed samples indicate enhanced sensitivity of the RT-nPCR assay. The RT-nPCR assay used in this research exhibited acceptable sensitivity, specificity, predictive value and repeatability for rapid detection of BVDV associated with the various samples obtained from an IVF system.

Animals↗
PubMed2005

Cryopreservation does not affect proliferation and multipotency of murine neural precursor cells.

Stem cell research offers unique opportunities for developing new medical therapies for devastating diseases and a new way to explore fundamental questions of biology. Establishing an efficient freezing protocol for neural precursor cells (NPCs) is of great importance for advances in cell-based therapies. We used fluorescence-activated cell sorter-based cell death/survival analysis and Western blot analysis of proliferation markers (proliferating cell nuclear antigen) and prosurvival proteins (Bcl-2) to study the effect of a variety of cryoprotective agents on fetal mouse forebrain NPCs. Neurospheres frozen at -70 degrees C or in liquid nitrogen in a rate-controlled manner and thawed after 5 days retained viability of 60%-70% measured 24 hours after thawing. However, 1 week after thawing, viability dropped to 50%-60%. Using a clonogenic sphere formation assay, we showed that recovery rate of frozen NPCs was approximately 26% and did not significantly differ between dimethyl sulfoxide (DMSO)- and glycerol-supplemented samples. Application of the caspase inhibitor zVAD-fmk during freezing or in the first week after thawing resulted in protection of cryopreserved neurospheres after thawing but not during the freezing process, indicating that apoptosis limits recovery of NPCs. Cell survival was not reduced in cells that were enzymatically separated before cryopreservation. Optimal protection of NPCs was achieved when 10% DMSO alone or in a combination with 10% fetal calf serum (FCS) was used. However, 10% glycerol alone was equally effective. Using these protocols, NPCs retained their multipotency and differentiated into both glial (GFAP-positive) and neuronal (Tuj1-positive) cells. Percentage of Tuj1-positive cells in 5% and 10% DMSO, in 10% DMSO + 10% FCS, and in 10% glycerol remained at the same level as before freezing and varied from 5%-7%. We conclude that cryopreservation (up to 1 month at -70 degrees C and up to 1 year in liquid nitrogen) does not markedly alter the rate of proliferation and multipotency of murine neural precursor cells.

Animals↗
PubMed2002

Effect of seminal plasma concentration and various extenders on postthaw motility and glass wool-Sephadex filtration of cryopreserved stallion semen.

OBJECTIVE: To compare the effect of semen extender and seminal plasma on postthaw motility and filtration through a glass wool-Sephadex (GWS) filter for frozen stallion semen. SAMPLE POPULATION: 7 stallions from which we collected > or = 3 ejaculates/stallion. PROCEDURES: 4 experiments were conducted to evaluate postthaw quality of frozen stallion semen. Kenney extender was compared with glucose-EDTA extender by use of various dilution rates that resulted in differing concentrations of seminal plasma. Stallions known to produce semen with poor postthaw quality were used to investigate whether a particular extender or dilution rate could improve ability of such semen to survive freeze-thaw procedures. RESULTS: Use of Kenney extender as the centrifugation extender significantly improved postthaw motility and GWS filtration, compared with glucose-EDTA. Extending semen at a dilution of 1:3 was significantly better than 1:1 for both motility and GWS filtration. In addition, including seminal plasma at a concentration of 5% in the cryopreserved semen resulted in significantly higher yield of spermatozoa after GWS filtration, compared with complete removal of SP or use of seminal plasma at 25%. Lastly, semen with poor postthaw quality had significantly improved postthaw quality in regard to motility and GWS filtration when semen was frozen with seminal plasma at a concentration of 5%, compared with semen frozen with seminal plasma at a concentration of 25%. CONCLUSIONS AND CLINICAL RELEVANCE: Use of Kenney extender at a high dilution (> or = 1:3) immediately after collection of semen can improve postthaw quality of frozen stallion semen.

Animals↗
PubMedDate not supplied

Cryopreservation of horse semen under laboratory and field conditions using a Stirling Cycle freezer.

A Stirling Cycle freezer has been developed as an alternative to conventional liquid nitrogen controlled rate freezers. Horse semen samples were cooled in 0.25 ml straws and 15 ml bags in the Stirling Cycle freezer under laboratory conditions and as a portable device, powered from a car battery. For comparison, straws were frozen in a conventional liquid nitrogen controlled rate freezer. Upon thawing, motility and viability of samples frozen in the Stirling Cycle freezer were not significantly different when compared to samples frozen in the liquid nitrogen freezer. Unlike liquid nitrogen systems, the Stirling Cycle freezer does not pose a contamination risk, can be used in sterile conditions and has no need for a constant supply of cryogen. The freezer has potential for use in veterinary and genetic conservation applications.

Animals↗
PubMed2005

Evaluation of gilthead sea bream, Sparus aurata, sperm quality after cryopreservation in 5 ml macrotubes.

Cryopreservation produces several types of damage in spermatozoa, leading to fertility impairment. The reduction arises both from a lower viability post-thaw and from sublethal dysfunctions in some of the surviving cells. In the present study, we have analysed the effect of cryopreservation in 5 ml macrotubes on the quality of post-thawed gilthead sea bream sperm. Several standard sperm quality parameters were determined: pH and osmolarity of seminal plasma, sperm concentration, and motility. An exhaustive determination of sperm quality before and after cryopreservation was investigated. Several parameters related with spermatozoal status were determined: ATP content, plasma membrane integrity and functionality, mitochondrial functionality, and sperm fertility. Our results demonstrated that gilthead sea bream spermatozoa suffer several types of damage after freezing/thawing. The percentage of viable cells slightly decreased after cryopreservation, however plasma membrane was affected by cryopreservation, since cells could not resist the hyperosmotic shock. Mitochondrial status was affected by cryopreservation since there was a decrease in the parameters of sperm motility, ATP content (3.17 nmol ATP/10(5) spermatozoa to 1.7 nmol ATP/10(5) spermatozoa in 1:20 frozen samples) and an increase of the percentage of cells with mitochondrial depolarized membranes (11% for fresh and 27% for 1:20 frozen samples). Fertility rate was similar either using fresh or frozen/thawed sperm (77 and 75% hatched larvae, respectively).

Animals↗
PubMed1990

The cryopreservation of donor semen by a simplified method: use in an IVF and GIFT programme.

The cryopreservation of semen used in assisted reproduction procedures was carried out exclusively by a simplified method in which a mixture of semen and cryoprotectant was contained in 1-ml tuberculin syringes and plunged directly into liquid nitrogen. Donor semen samples halved and frozen in syringes and in straws in a controlled-rate freezer showed no significant difference in post-thaw motility (P = 0.217) or survival (P = 0.217) after 30 min. However, after 180 min the survival rate showed a significant reduction in syringes (P = 0.045). A significant difference (P less than 0.00008) in the rate of fertilization of oocytes was seen in IVF cycles using frozen-thawed donor sperm (58/142, 42%) when compared to fresh sperm from husbands (2315/3926, 59%). A significant reduction (P less than 0.00005) in fertilization rate was also observed in the case of supernumerary oocytes in GIFT cycles with the cryopreserved donor sperm (29/132, 22%) compared to the husbands' sperm (239/514, 46%). However, the pregnancy rate following IVF and embryo replacement was the same after fertilization with fresh sperm (75/351, 21%) as opposed to frozen sperm (3/14, 21%). Furthermore, a higher pregnancy rate was observed in GIFT with frozen donor sperm (9/19, 47%) than with fresh sperm from husbands (28/103, 27%), though this was not statistically significant (P = 0.079). These results show this simplified methods of semen cryopreservation to be effective when used in an IVF and GIFT programme, giving pregnancy rates comparable to fresh normospermic semen samples. The method is simple, quick and inexpensive.

Cell Survival↗