Circulating Cd34+ cell count differentiates primary myelofibrosis from other Philadelphia-negative myeloproliferative neoplasms: a pragmatic study.

A high number of circulating CD34+ cells has been advocated to distinguish primary myelofibrosis from other Philadelphia-negative myeloproliferative neoplasms. We re-evaluated the diagnostic interest of measuring circulating CD34+ cells in 26 healthy volunteers and 256 consecutive patients at diagnosis for whom a myeloproliferative neoplasm was suspected. The ROC curve analysis showed that a number of CD34+ <10/µl excludes the diagnosis of primary myelofibrosis with a sensitivity of 97 % and a specificity of 90 % (area under the curve: 0.93 [0.89-0.98]; p < 0.001). Patients with PMF harboring a CALR mutation had more circulating CD34+ cells than patients with either a JAK 2 or MPL mutation (p = 0.02 and p < 0.01, respectively). These results suggest that this fast, simple, non-invasive, and standardized test is of particular interest to exclude the diagnosis of primary myelofibrosis.

Histone H3 E50K mutation confers oncogenic activity and supports an EMT phenotype.

Sequencing of human patient tumors has identified recurrent missense mutations in genes encoding core histones. We report that mutations that convert histone H3 amino acid 50 from a glutamate to a lysine (H3E50K) support an oncogenic phenotype in human cells. Expression of H3E50K is sufficient to transform human cells as evidenced by a dramatic increase in cell migration and invasion, and a statistically significant increase in proliferation and clonogenicity. H3E50K also increases the invasive phenotype in the context of co-occurring BRAF mutations, which are present in patient tumors characterized by H3E50K. H3E50 lies on the globular domain surface in a region that contacts H4 within the nucleosome. We find that H3E50K perturbs proximal H3 post-translational modifications globally and dysregulates gene expression, activating the epithelial to mesenchymal transition. Functional studies using S. cerevisiae reveal that, while yeast cells that express H3E50K as the sole copy of histone H3 show sensitivity to cellular stressors, including caffeine, H3E50K cells display some genetic interactions that are distinct from the characterized H3K36M oncohistone yeast model. Taken together, these data suggest that additional histone H3 mutations have the potential to be oncogenic drivers and function through distinct mechanisms that dysregulate gene expression.

Retrospective Review of Acute Renal Colic Management in the Emergency Department and Review of Guidelines.

INTRODUCTION: The influence of multispecialty guidelines on practice patterns in the emergency department is unknown. We documented practice patterns in our emergency department among patients presenting with acute renal colic. METHODS: We identified practice patterns in the treatment of nephrolithiasis in our emergency department via a retrospective chart review of 469 patients from 2013 to 2015. We compared practice patterns to available guidelines over the domains of 1) diagnostic and imaging studies, 2) medications and 3) referral to urology. RESULTS: There was a slight preference toward noncontrast computerized tomography (29%) as a single modality imaging study compared to renal ultrasound (26%). Overall 74% of renal ultrasounds were completed at bedside by emergency department physicians. Alpha blockers were used for medical expulsive therapy in 47% of patients. However, 133 patients with ureteral stones did not receive medical expulsive therapy. Only 34% of the total cohort received a urology consultation in the emergency department or subsequent outpatient referral. CONCLUSIONS: We noted variability in practice patterns for patients presenting with nephrolithiasis in the emergency department compared to guidelines provided by several professional organizations. There is inconsistent use of imaging studies, underuse of medical expulsive therapy and underuse of urology, highlighting a need for collaborative standardization of a diagnostic and treatment protocol to enhance quality of care.

Uptake, efflux, and hydrolysis of aclacinomycin A in Friend leukemia cells.

The kinetics of uptake by cells and nuclear incorporation of aclacinomycin A was studied in Friend leukemia cells. It was shown that uptake is a very rapid process. The intracellular concentration is maximum in 10 min and mainly (about 75%) localized in the nucleus. Most of the incorporated drug will disappear from the cell by a two-step mechanism: (a) efflux from the nucleus to the cytoplasm; and (b) deglycosidation at C-7 to the alkavinone form in the cytoplasmic fraction. The cellular uptake was temperature dependent but was not prevented by sodium azide treatment. We assumed, therefore, that it is related to the composition and to the dynamic structure of the cell surface membrane. Nuclear outward transport and deglycosidation were inhibited by sodium azide and low temperatures; this suggests that they are regulated by an active transport process and by an enzymatic activity, respectively.

Fate of aclacinomycin-A and its metabolites effect on cell growth and macromolecular synthesis.

The relationship between the structure and activity of aclacinomycin-A (ACM) metabolites was investigated in vitro in Friend leukaemia cells (FLC). The cytotoxic effect was related to the ease with which ACM and its metabolites accumulate in the nucleus. Cellular uptake and nuclear incorporation are influenced by the hexopyranoses linked to aklavinone (AKV) and by the two methyls linked to the L-rhodosamine amino groups. The effect of ACM and its metabolites on macromolecular synthesis depended on the drug concentrations and the exposure time. ACM was the most active in the inhibition of nucleic acid synthesis whereas it had no direct effect on protein synthesis even at high drug concentrations. When cells were treated for a short time with low drug concentrations (1 microM), RNA synthesis was inhibited to a greater extent than DNA synthesis. But when incubated for longer periods, inhibition of DNA synthesis increased further. RNA and DNA syntheses were both inhibited to about the same extent only when cells were exposed to the higher drug concentrations (10 microM). We conclude therefore that at low drug concentrations the effect on DNA synthesis is probably a consequence of RNA synthesis inhibition. The early DNA synthesis inhibition which occurs at higher drug concentrations may result from the direct action on the cellular genome.

Biochemical and cytotoxic properties of the isomeric forms of N,N'-bis[N-2-chloroethyl)-N-nitrosocarbamoyl] cystamine.

Three isomeric forms of a cystamine-containing chloroethylnitrosourea, N,N'-bis[N-(2-chloroethyl)-N-nitrosocarbamoyl]cystamine (CNCC), have been identified and separated by high pressure liquid chromatography. Isomer S, 3,3'-bis[N-(2-chloroethyl)-N-nitrosocarbamoyl] ethyl disulfide, was significantly less cytotoxic than isomer C, 1,1'-bis [N-(2-chloroethyl)-N-nitrosocarbamoyl] ethyl disulfide, or isomer M, 1,3'-bis[N-(2-chloroethyl)-N-nitrosocarbamoyl] ethyl disulfide, in either a human Namalva lymphoblastoid or a rat Walker 256 carcinoma cell line. Both isomers S and C inhibited DNA synthesis at a 50 microM concentration. A structural analysis of the isomeric forms suggested that bioreduction of the disulfide bond would permit both isomers to produce isocyanate moieties which would carbamoylate intracellular proteins and depress nucleic acid synthesis. The reduced cytotoxic potential of isomer S is consistent with a prolongation in the half-life of production of alkylating carbonium species that lack the capacity to cross-link macromolecules. Overall, the relative position of the NH group within each of the nitrosourea isomers appears critical to the biological properties of the drug.

Induction of ovulation in clomiphene-resistant polycystic ovary syndrome with pulsatile GnRH.

OBJECTIVE: To determine the efficacy of pulsatile GnRH alone and in combination with clomiphene citrate or gonadotropins in a stepwise approach for inducing ovulation in women with clomiphene-resistant polycystic ovary syndrome (PCOS). METHODS: Eighty women with clomiphene-resistant anovulatory infertility and PCOS were given subcutaneous pulsatile GnRH (15 micrograms every 90 minutes) using a portable infusion pump. If no follicular development was seen, clomiphene citrate (100 mg/day for 5 days) was given concurrently with the hormone in the next cycle of treatment. Those who still failed to ovulate regularly were treated with combined pulsatile GnRH with intramuscular gonadotropins (one ampule per day for 5-7 days). RESULTS. Sixty-six of 131 (50%) pulsatile GnRH cycles, 94 of 142 (66%) pulsatile GnRH with clomiphene cycles, and 48 of 69 (70%) pulsatile GnRH with gonadotropin cycles were ovulatory. Monofollicular response (one follicle at least 14 mm on the day of ovulation) occurred in 80.6, 83.9, and 53.6% of cycles, and multifollicular response occurred in 4.8, 3.1, and 21.6% of cycles in the three groups, respectively. Mild ovarian hyperstimulation occurred in one of the 342 cycles. The cumulative conception rate was 30% after three cycles, 60% after six cycles, and 73% after nine cycles. The miscarriage rate was 22% (ten of 45 pregnancies), and 35 women (78%) had live births (33 singletons and two sets of twins). CONCLUSION: The use of subcutaneous pulsatile GnRH alone and in combination with clomiphene citrate or gonadotropins for induction of ovulation in clomiphene-resistant PCOS in a stepwise approach produces a high cumulative conception rate associated with a low rate of multiple pregnancy and ovarian hyperstimulation syndrome.

Early prediction of ovarian multifollicular response during ovulation induction in patients with polycystic ovary syndrome.

OBJECTIVE: To examine the association between the midfollicular FSH-LH ratio and the number of follicles, and the multifollicular ovarian response to gonadotropin stimulation in patients with polycystic ovary syndrome (PCOS) with normal basal LH and FSH levels. SUBJECT(S): Eighteen patients who had an abandoned treatment cycle because of multifollicular ovarian response. For comparison, all other completed treatment cycles in the same group of patients were used. MAIN OUTCOME MEASURE(S): The dose of hMG or FSH, daily effective dose, day 8 serum FSH and LH concentration, day 8 number of follicles > or = 8 mm, E2 and number of follicles on hCG day or day of cycle was abandoned. RESULT(S): In the abandoned cycles, day 8 serum LH concentrations were significantly lower and day 8 number of follicles and FSH-LH ratios were significantly higher compared with the completed cycles. A high predictive power (> 90%) for multifollicular response was established by using a set of two criteria: a FSH-LH ratio > or = 1.6 and the number follicles > or = 7 as the cutoff point. CONCLUSION(S): When aiming for a monofollicular response in women with PCOS and normal basal FSH and LH levels, cycles with high midfollicular FSH-LH ratios (> or = 1.6) and a high number of follicles (> or = 7) are those prone to develop a multifollicular ovarian response.

Effect of laparoscopic ovarian electrocautery on ovarian response and outcome of treatment with gonadotropins in clomiphene citrate-resistant patients with polycystic ovary syndrome.

OBJECTIVE: To evaluate the effect of ovarian electrocautery on the ovarian response to gonadotropic stimulation and pregnancy rate (PR) in clomiphene citrate (CC)-resistant women with polycystic ovary syndrome (PCOS) and high basal serum LH levels. DESIGN: Retrospective study. SETTING: Outpatient infertility clinic in a tertiary referral center. SUBJECTS: Twenty-two women with PCOS, high basal serum LH concentrations, and CC resistance who underwent laparoscopic ovarian electrocautery. Treatment with gonadotropin was scheduled after failure to ovulate spontaneously or conceive after electrocautery. Data from gonadotropin-stimulated cycles were compared with data from treatment cycles in the same patients before ovarian electrocautery. MAIN OUTCOME MEASURES: Number of ampules, duration of induction phase, daily effective dose, PR, and pregnancy outcome. RESULTS: Markedly reduced basal serum LH concentrations and normal menstrual cyclicity in 41% of patients were recorded after laparoscopic ovarian electrocautery. Comparison of gonadotropin-stimulated cycles before and after electrocautery revealed significantly higher rates of ovulation and pregnancy after electrocautery as well as significant reduction in the number of ampules, daily effective dose, and duration of the induction phase with hMG and in daily effective dose with FSH. CONCLUSIONS: Our results indicate an increased ovarian sensitivity to gonadotropins after laparoscopic ovarian electrocautery. A preference for laparoscopic ovarian electrocautery over medical treatment in all or selected groups of CC-resistant PCOS patients is suggested.

Incubation with sperm enhances in vitro maturation of the oocyte from the germinal vesicle to the M2 stage.

OBJECTIVE: To evaluate the effect of sperm in the culture medium on the rate of oocyte maturation in vitro from the germinal vesicle to the M2 stage. DESIGN: Prospective randomized controlled study. SETTING: The IVF Unit, Wolfson Medical Center, Holon, Israel. PATIENT(S): All women in whom oocytes were retrieved at the germinal vesicle stage between December 1995 and March 1996. INTERVENTION(S): Oocytes retrieved at the germinal vesicle stage were divided prospectively and randomly into four groups of incubation conditions: group 1, intact germinal vesicle with cumulus; group 2, intact germinal vesicle with sperm cells in the culture medium; group 3, stripped germinal vesicle; and group 4, stripped germinal vesicle with sperm cells. Oocytes were observed 24 hours after retrieval, and the stage of maturation was recorded. Oocytes that reached the M2 stage underwent the intracytoplasmic injection procedure, and the fertilization rate in each group was recorded at 48 hours. MAIN OUTCOME MEASURE(S): Maturation rate from the germinal vesicle to M2 stage and fertilization rate. RESULT(S): Each group contained 20 germinal vesicle oocytes. In groups 1 and 2, 2 (10%) and 9 (45%) oocytes, respectively, reached the M2 stage at 24 hours; at 48 hours, 1 (5%) and 8 (40%) embryos developed, respectively. The results in group 2 were significantly higher than in group 1. In groups 3 and 4, 6 (30%) and 16 (80%) oocytes, respectively, reached the M2 stage at 24 hours; at 48 hours, 5 (25%) and 14 (70%) embryos developed, respectively. Results in group 4 were significantly higher than those in groups 1, 2, and 3. CONCLUSION(S): Both methods of oocyte activation (i.e., addition of sperm to the culture medium or removal of the cumulus) enhance oocyte maturation in vitro, but the sperm-incubation method has a more pronounced effect. A combination of both methods leads to an exceptionally high rate of oocyte maturation, followed by a high fertilization rate.

Poor outcome with round spermatid injection in azoospermic patients with maturation arrest.

OBJECTIVE: To compare the outcome of intracytoplasmic sperm injection (ICSI) and round spermatid injection (ROSI), both obtained by testicular sperm extraction (TESE), and to compare the results of fresh versus frozen ROSI. DESIGN: Retrospective study. SETTING: An IVF unit at a university hospitalPatient(s): Eighteen infertile couples with nonobstructive azoospermia. INTERVENTION(S): TESE with ROSI or ICSI of mature spermatozoa into metaphase II oocytes was performed. The resulting embryos were transferred to female partners. The spare round spermatids were frozen. MAIN OUTCOME MEASURE(S): Fertilization and cleavage rates, embryo quality, and clinical pregnancy rates. RESULT(S): Seventeen ROSI cycles and six ICSI cycles were compared. Fertilization rate following ROSI (44.9%) was significantly lower than with ICSI (69%). A significantly higher rate of cleavage arrest occurred following ROSI (40.8%) as compared to ICSI (8.2%). The morphology of embryos resulting from ROSI was significantly poorer. No pregnancies were achieved following ROSI as compared to a 50% clinical pregnancy rate in the ICSI group. The fertilization and cleavage rates following ROSI with fresh versus frozen-thawed spermatids were comparable. CONCLUSION(S): In azoospermic patients with maturation arrest at the stage of round spermatids the efficiency of ROSI appears to be extremely poor. The role of ROSI in the treatment of nonobstructive azoospermia should be reevaluated.

Zygote intrafallopian transfer in patients with tubal factor infertility after repeated failure of implantation with in vitro fertilization-embryo transfer.

OBJECTIVE: To evaluate the efficacy of zygote intrafallopian transfer (ZIFT) in terms of implantation and pregnancy rates in patients with tubal factor infertility and repeated implantation failure in IVF-ET cycles. DESIGN: Retrospective analysis of ZIFT cycles. SETTING: An IVF unit in a university hospital. PATIENT(S): Criteria for patient selection for ZIFT included at least four failures of implantation in IVF-ET cycles in which at least 3 embryos were replaced per transfer and a cause of infertility diagnosed as male, unexplained, or tubal factor with proof of one patient tube. INTERVENTION(S): Four to six zygotes were transferred by laparoscopy into the fallopian tube 24-26 hours after oocyte retrieval. MAIN OUTCOME MEASURE(S): Implantation and pregnancy rates were determined in 112 ZIFT cycles performed in 81 patients with repeated failure of implantation. Results were further stratified for patients with tubal factor (n = 15) and patients without tubal factor (n = 66). RESULT(S): The pregnancy and implantation rates for all ZIFT cycles were 35.1% and 11.1%, respectively. Pregnancy and implantation rates per cycle in patients with tubal factor versus patients without tubal factor were 26.6% versus 37.1% and 9.4% versus 11.4%, respectively. CONCLUSION(S): ZIFT can be considered as a mode of treatment for patients with repeated failure of implantation in IVF-ET and with tubal factor with proved patency of one tube.

Zygote intrafallopian transfer may improve pregnancy rate in patients with repeated failure of implantation.

OBJECTIVE: To evaluate the efficacy of zygote intrafallopian transfer (ZIFT) on implantation rates and pregnancy rates (PRs) in patients with repeated failure of implantation in IVF-ET cycles. DESIGN: A case-control study. PATIENT(S): Criteria for patient selection included male factor or unexplained infertility, normal uterine cavity, and at least three failures of implantation in IVF-ET cycles in which at least three embryos were placed per transfer. Data on 70 patients who underwent 92 ZIFT cycles are presented. A control group consisted of patients with the same selection criteria who underwent an additional standard IVF-ET cycle during the same time period. INTERVENTION(S): Ovulation induction consisted of down-regulation with GnRH analogue followed by ovarian stimulation with FSH and hMG. Intracytoplasmic sperm injection was performed on the oocytes of all patients with male factor infertility. Zygotes were transferred by laparoscopy into the fallopian tube 24-26 hours after oocyte retrieval. MAIN OUTCOME MEASURE(S): Implantation rates and PRs in the ZIFT and control groups were compared. RESULT(S): The PRs and implantation rates were significantly higher in the ZIFT group than in the control group: 34.2% (24/70) and 8.7% (29/333) versus 17.1% (12/70) and 4.4% (13/289), respectively (P = 0.002 and P = 0.04). The cumulative conception rate for two ZIFT cycles was 59.3%. CONCLUSION(S): Zygote intrafallopian transfer should be considered a beneficial mode of treatment for patients with repeated failure of implantation in IVF and transcervical ET. More prospective randomized studies are needed to support this observation.

Estradiol supplementation during the luteal phase may improve the pregnancy rate in patients undergoing in vitro fertilization-embryo transfer cycles.

OBJECTIVE: To evaluate the effect of adding E(2) to progestin supplementation during the luteal phase on pregnancy and implantation rates in patients undergoing IVF cycles. DESIGN: Prospective, randomized study. SETTING: An IVF unit in a university hospital. PATIENT(S): Patients who were undergoing IVF with controlled ovarian hyperstimulation using a GnRH analog and who had E(2)2,500 pg/dL at the time of hCG administration. INTERVENTION(S): Serum concentrations of E(2) and progesterone were measured in all patients on days 7, 10, and 12 after ET. MAIN OUTCOME MEASURE(S): The E(2) and progesterone profiles of the luteal phase and the pregnancy and implantation rates were documented. Data were analyzed for the entire study population and further stratified according to the GnRH analog protocol used (short or long). RESULT(S): Significantly higher E(2) levels were found during the luteal phase in the group that received E(2) supplementation. This effect was more pronounced in the patients who were treated with the long GnRH analog protocol. Significantly higher pregnancy and implantation rates were recorded in the patients who received E(2) supplementation and were treated with the long GnRH analog protocol. CONCLUSION(S): For patients who are treated with the long GnRH analog protocol for controlled ovarian hyperstimulation and for whom luteal support with hCG is contraindicated, the addition of E(2) to the progestin support regimen may have a beneficial effect on pregnancy and implantation rates.

Polycystic ovary syndrome patients as oocyte donors: the effect of ovarian stimulation protocol on the implantation rate of the recipient.

OBJECTIVE: To evaluate the outcome of oocytes donated by women with polycystic ovarian syndrome (PCOS) compared with oocytes donated by women with mechanical infertility. DESIGN: A retrospective study. PATIENTS: The outcome of 159 oocyte donation cycles with oocyte donated by PCOS patients were compared with 69 oocyte donation cycles with oocytes donated by patients with mechanical infertility. We compared the stimulation protocols in the donors to assess if the combination of GnRH analogue (GnRH-a), FSH, and hMG has an advantage over FSH and hMG alone with respect to their effect on fertilization and implantation rates in oocyte donation cycles. RESULTS: When treated with GnRH-a, pregnancy rates in PCOS and mechanical infertility donors were higher than those treated with FSH and hMG alone. The comparison between PCOS and mechanical factor oocyte recipients revealed no significant difference in the pregnancy and abortion rates, but the oocytes of patients with PCOS that were exposed to GnRH-a had a significantly higher implantation rate than those not exposed to GnRH-a. CONCLUSIONS: Oocytes obtained from PCOS patients had a fertilization potential equal to oocytes obtained from mechanical infertility donors. Furthermore, because the oocytes of patients with PCOS exposed to GnRH-a had a significantly higher implantation rate, a detrimental role of high LH on oocyte quality seems probable. However, because PCOS has a high familial prevalence, some reservations may arise due to a possible propagation of the problem in the next generation of oocyte donation programs.

Minidose gonadotropin-releasing hormone agonist is the treatment of choice in poor responders with high follicle-stimulating hormone levels.

OBJECTIVE: To investigate the effectiveness of minidose GnRH agonist (GnRH-a) + hMG in poor responders with elevated basal level FSH. DESIGN: Retrospective analysis of IVF cycles. SETTING: IVF Unit, Golda Medical Center, Petah Tikva, Israel. PATIENTS: One hundred six patients who were defined as poor responders on two previous IVF attempts. Three treatment protocols of midluteal Decapeptyl (D-Trp6) were compared: [1] a single-dose of 3.75 mg; [2] 0.5 mg daily until menstruation, followed by 0.1 mg daily; and [3] 0.1 mg daily until menstruation, followed by 0.05 mg daily. MAIN OUTCOME MEASURES: Comparisons were made among the three protocols regarding basal FSH levels, number of oocytes retrieved and fertilized, number of days of stimulation, follicular phase, P levels, and pregnancy and miscarriage rates. RESULTS: Treatment with minidose GnRH-a resulted in higher E2 levels and lower P levels on the day of hCG and lower cancellation rates. Furthermore, a higher number of oocytes recovered and fertilized and embryos transferred were recorded. The trend indicated improved pregnancy and implantation rates with a lower miscarriage rate. CONCLUSION: Minidose GnRH-a is a better choice than regular GnRH-a strategies in poor-responder patients undergoing IVF treatment.

Acute pelvic inflammatory disease after oocyte retrieval: adverse effects on the results of implantation.

OBJECTIVE: To determine the impact of pelvic inflammation on the results of IVF after oocyte retrieval. DESIGN: Retrospective analysis of IVF cycles. SETTING: IVF Unit, Golda Medical Center, Petah Tikva, Israel. PATIENTS: Twenty-eight women with a diagnosis of pelvic inflammatory disease (PID) during IVF therapy. MAIN OUTCOME MEASURE: The pregnancy rate (PR) of IVF cycles complicated by PID after oocyte retrieval was compared with our ongoing IVF results. RESULTS: All 28 women with PID during IVF treatment did not conceive, despite the high number of oocytes retrieved, fertilized, and transferred. The PR over the same period was 23% to 31%. CONCLUSIONS: Pelvic infection after IVF treatment might have a detrimental effect on the results of treatment. In an effort to maximize the chances for normal implantation, postponement of ET should be considered when pelvic infection or inflammation is diagnosed.

The value of repeat hysteroscopic evaluation in patients with failed in vitro fertilization transfer cycles.

One hundred ten women with normal initial hysteroscopy who failed to conceive during three or more IVF-ET cycles underwent repeat hysteroscopic evaluation. In 20 patients (18.2%), visualization revealed uterine abnormalities, mainly newly added endometrial lesions, i.e., hyperplasia, polyps, endometritis, and synechiae. Our results indicate that repeat hysteroscopic evaluation, in cases of recurrent IVF-ET failure, is an important adjunctive method for further evaluating and possibly optimizing the IVF-ET procedure.

Timing of testicular sperm retrieval procedures and in vitro fertilization-intracytoplasmic sperm injection outcome.

OBJECTIVE: To compare the outcome of IVF-intracytoplasmic sperm injection (ICSI) using testicular spermatozoa obtained on the day of ovum pick-up (OPU) or on the day before OPU. DESIGN: Retrospective study. SETTING: An IVF clinic in a university hospital. PATIENT(S): Forty-seven IVF-ICSI cycles using testicular spermatozoa in 28 couples with the male partner suffering from nonobstructive azoospermia. INTERVENTION(S): Sperm retrieval was performed either on the OPU day (23 cycles in 19 patients; group A) or on the day before OPU (24 cycles in 15 patients; group B). Testicular sperm aspiration (TESA) was performed and followed by testicular sperm extraction (TESE) if no spermatozoa could be found. MAIN OUTCOME MEASURE(S): The presence of motile spermatozoa at the time of ICSI and fertilization and clinical pregnancy rates. RESULT(S): A similar proportion of motile spermatozoa (60.9% vs. 62.5%), fertilization rate (61.7% vs. 58.9%), and clinical pregnancy rate per transfer (34.8% and 29.2%) were obtained for groups A and B, respectively. CONCLUSION(S): Testicular sperm retrieval can be performed on the day before OPU without compromising success. Considerable medical and practical advantages may be offered by further advancement of testicular sperm retrieval procedures to 48 hours before OPU. This approach should thus be further evaluated.