Comparison of acute and long-term outcomes of Evolution® and TightRail™ mechanical dilator sheaths during transvenous lead extraction.

BACKGROUND: Powered transvenous lead extraction (TLE) tools are commonly required to remove the leads with long implant duration due to fibrotic adhesions. However, comparative data are lacking among different types of TLE tools. AIM: To compare the efficacy and safety of two different rotational mechanical dilator sheaths in retrospectively analyzed patients who underwent TLE. METHODS AND RESULTS: A total of 566 lead extractions from 302 patients using TightRail™ (333 lead extractions from 169 patients) and Evolution® (233 lead extractions from 133 patients) mechanical dilator sheaths were performed between July 2009 and June 2018. Acute and long-term outcomes of study groups were compared. There is no statistically significant difference between Evolution® and TightRail™ groups in procedural success (93.9% vs. 94%), clinical success (99.2% vs. 98%), and major complications (3.8% vs. 1.2%), respectively (p > .05). In multivariate regression analysis, lead dwell time, the number of extracted leads, and baseline leukocyte count were found as independent predictors of procedural success (p < .05). During the median follow-up of 36.6 (0.2-118) months, all-cause mortality was observed in 73 patients (25.6% in the Evolution® vs. 23.1 in the TightRail™ group, p > .05). Chronic renal disease, heart failure, and coagulopathy were shown as independent predictors of all-cause mortality in multivariate regression analysis (p < .05). CONCLUSION: TLE using TightRail™ or Evoluation® mechanical dilator sheaths was a safe and effective therapeutic option. Both mechanical dilator sheaths showed similar efficacy, safety, and all-cause mortality at acute and long-term follow-up of patients who underwent TLE.

Pulmonary hypertension in Takayasu arteritis.

AIM: To determine the frequency and define the causes of pulmonary hypertension (PH) in patients with Takayasu arteritis (TA). METHOD: Sixty-four TA patients were evaluated by transthoracic echocardiography (TTE). Having an estimated systolic pulmonary arterial pressure (sPAP) ≥40 mm Hg by echocardiography or if performed, mean PAP ≥25 mm Hg in right heart catheterization was defined as PH. Clinical, imaging and laboratory results of the TA patients were obtained from hospital files. RESULT: In total, seven (10.9%) patients had PH. Four patients had PH due to left-sided heart disease (group 2 PH), three patients due to pulmonary arterial involvement (PAI; group 4 PH) and one patient due to atrial septal defect (group 1 PH). In one patient, combination of PAI, aortic insufficiency and pulmonary venous return anomaly was present and he was considered to have both group 2 and group 4 PH. PAI was more frequent (42.9% vs 15.7%) in patients with PH but the difference was not statistically significant. The percentage of patients treated with cyclophosphamide and/or biologics was higher in the group with PH as compared to the group without PH (P = 0.015). One patient with group 4 PH had been on pulmonary arterial hypertension (PAH)-specific agents for 8 years. CONCLUSION: Pulmonary hypertension is not infrequent in TA patients and all the potential causes of PH should be carefully evaluated. Patients with severe or treatment-resistant disease are prone to have PH. PAH-specific agents may be effective in patients with group 4 PH.

Effects of serum uric acid levels on the arginase pathway in women with metabolic syndrome.

BACKGROUND: Elevated serum uric acid levels and increased arginase activity are risk factors for cardiovascular diseases (CVD). The aim of the present study was to investigate effects of serum uric acid levels on the arginase pathway in women with metabolic syndrome (MetS). METHODS: Serum arginase activity, and nitrite and uric acid levels were measured in 48 women with MetS and in 20 healthy controls. The correlation of these parameters with components of MetS was also evaluated. RESULTS: Our data show statistically higher arginase activity and uric acid levels but lower nitrite levels in women with MetS compared to controls. Serum uric acid levels were negatively correlated with HDL cholesterol, nitrite levels and positively with Body Mass Index, waist to hip ratio, triglyceride and total cholesterol levels, systolic blood pressure, Homeostasis Model Assessment-Insulin Resistance-Index, serum arginase activity, and LDL-cholesterol levels in women with MetS. CONCLUSION: Results of the present study suggest that serum uric acid levels may contribute to the pathogenesis of MetS through a process mediated by arginase pathway, and serum arginase activity and nitrite and uric acid levels can be used as indicators of CVD in women with MetS.

The Association of Serum Galectin-3 Levels with Atrial Electrical and Structural Remodeling.

INTRODUCTION: Left atrial (LA) interstitial fibrosis is known to have a role in the initiation and maintenance of atrial fibrillation (AF). The role of galectin-3 in the pathogenesis of cardiac fibrosis has been demonstrated in previous studies. We aimed to determine whether serum galectin-3 level is associated with markers of atrial remodeling, including the extent of LA fibrosis detected by delayed enhancement magnetic resonance imaging (DE-MRI) and atrial electromechanical delay (AEMD) in paroxysmal AF patients with preserved left ventricular (LV) functions. METHODS AND RESULTS: Thirty-three patients (58 [28-74] years, 51.5% male) with paroxysmal AF who underwent DE-MRI prior to cryoballoon-based AF ablation were included in the study. Serum galectin-3 levels were measured with ELISA. LA volume index (B ± SE: 0.424 ± 0.504, 95% CI: 0.560-2.627, P = 0.004) and serum galectin-3 levels (B ± SE: 0.549 ± 7.745, 95% CI: 16.874-47.550, P < 0.001) were found to be independently correlated with extent of LA fibrosis detected with DE-MRI in paroxysmal AF patients with preserved LV function. Correlation analysis between AEMD parameters and baseline characteristics showed that galectin-3 was significantly correlated with intra-left (ρ = 0.432, P = 0.012) and inter-AEMD (ρ = 0.395, P = 0.023). Duration of AF, LAD, and extent of LA fibrosis were also found to be significantly correlated with AEMD parameters. CONCLUSION: This is a hypothesis-generating study pointing out that serum galectin-3 level is significantly associated with atrial remodeling in paroxysmal AF patients with preserved LV function. Further studies are necessary to provide exact pathophysiological mechanisms.

Elevated M2-muscarinic and ß1-adrenergic receptor autoantibody levels are associated with paroxysmal atrial fibrillation.

BACKGROUND: Pathophysiologic mechanisms underlying lone atrial fibrillation (AF) have not been clearly demonstrated yet. Emerging evidence has indicated that autoimmunity may play a role in the development of AF. Relationship between serum anti-M2-muscarinic receptor autoantibody (anti-M2-R) and anti-ß1-adrenergic receptor autoantibody (anti-ß1-R) levels and lone paroxysmal atrial fibrillation (PAF) has not been investigated. We aimed to compare anti-M2-R and anti-ß1-R levels between lone PAF patients and healthy control subjects. METHODS AND RESULTS: 75 patients with lone PAF (age: 52.80 ± 6.80 years, 53 % male) and 75 healthy control subjects (age: 53.30 ± 6.80 years, 54 % male) were enrolled in the study. Serum anti-M2-R and anti-ß1-R levels were measured by ELISA and compared between two groups. Anti-M2-R [142.30 (77.65-400.00) vs. 69.00 (39.48-299.04) ng/mL; p < 0.001) and anti-ß1-R [102.56 (65.18-348.41) vs. 44.17 (30.89-158.54) ng/mL; p < 0.001] levels were significantly higher in patients with lone PAF compared to healthy controls. Multivariate regression analysis showed that left atrial diameter (OR: 1.471, p < 0.001), hs-CRP(OR: 1.940, p < 0.001), anti-M2-R (OR: 1.158, p < 0.001) and anti-ß1-R (OR: 1.296, p < 0.001) levels were independent predictors for the presence of lone PAF. Using a cut-off level of 101.83 ng/mL, anti-M2-R levels predicted presence of lone PAF with a sensitivity of 94.68 % and specificity of 81.33 %. Anti-ß1-R levels predicted presence of lone PAF with a sensitivity of 92.00 % and specificity of 73.30 %, using a cut-off level of 72.16 ng/mL. CONCLUSION: Our results demonstrated that higher serum anti-M2-R and anti-ß1-R levels are associated with lone PAF. Autoantibodies related to autonomic system may play an important role in the development of lone AF.

Effect of age and plaque morphology on diagnostic accuracy of dual source multidetector computed tomography coronary angiography.

BACKGROUND: Multidetector computed tomography (MDCT) coronary angiography represents one of the most exciting technological revolutions in cardiac imaging and it has been increasingly used in the diagnosis of coronary artery disease. The purpose of this study is to investigate the effect of age and coronary plaque calcification on diagnostic accuracy of MDCT. METHODS: The patients were examined by using dual-source MDCT and conventional coronary angiography. MDCT results were analyzed with regard to the severity (> 50% stenosis) and morphology (non-calcified, mixed, or calcified) of coronary atherosclerotic plaques evaluated in a 16-segment model. RESULTS: In total, 181 patients (94 men and 87 women) with 2,687 coronary artery segments were examined with MDCT. Ninety three patients were older than 65 years of age (group A, 42 men) and 88 were younger (group B, 52 men). Two-hundred nine coronary artery segments (7.2%) were excluded because of small distal coronary vessel segments and/or motion artifacts. The overall number of segments with non-diagnostic image quality was similar in both groups of patients. Of the 2,687 evaluated segments, 157 (5.8%) were significantly diseased, and 144 of them were correctly detected by MDCT. Diagnostic evaluation showed that the sensitivity, positive predictive value, specificity, and negative predictive value were 89.5%, 62.5%, 96.0%, and 99.2%, respectively in group A, and 95.2%, 64.8%, 97.5%, and 99.8% in group B, respectively. In addition, detailed segment-based analyses in coronary segments with non-calcified, mixed and calcified plaques in both groups were similar diagnostic accuracy. CONCLUSIONS: Very high diagnostic accuracy observed in this study suggests that MDCT coronary angiography could be a suitable diagnostic tool for not only younger patients but also for older patients.

The effects of gender difference on monocrotaline-induced pulmonary hypertension in rats.

The present study aimed to compare the effect of gender difference on hemodynamic consequences in the development of monocrotaline (MCT)-induced pulmonary hypertension in rat. The effect of antioxidant enzyme systems on the development of pulmonary hypertension mediated by the phytotoxin MCT and the effect of gender on these antioxidant systems were also investigated. For this purpose, the right ventricular pressures (RVPs) and right ventricular/heart weight (HW) ratios were compared between groups and the glutathione (GSH) level and superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities were determined in lung and liver tissue samples of rats. RVP and right ventricular/HW ratios significantly increased in the MCT group compared to the control group. In the MCT group, RVP was significantly higher in males than females. MCT-induced pulmonary hypertension resulted in decreased GSH level, decreased GST and SOD activities and increased CAT activity in lung and liver tissues of both male and female rats. In addition, the lung and liver GSH level and GST and SOD levels were higher in female control rats compared to male control rats. The results of the present study, that antioxidant enzyme activities were different between the groups, highlight the possible role of oxidative stress in the pathogenesis of MCT-induced pulmonary hypertension in rats. Moreover, the lower antioxidant defense capacity of male rats than female rats may be considered as a cause of more aggressive course of MCT-induced pulmonary hypertension in males compared to females.

Evaluation of low-dose letrozole addition to ovulation induction in IVF.

PURPOSE: The aim was to investigate the impact of low-dose letrozole usage along with gonadotropin treatment in vitro fertilization (IVF) cycles in comparison to gonadotropin treatment alone. MATERIALS AND METHODS: Fifty patients were prospectively included in this randomized study and were divided into two groups. Age, demographic features, causes, and period of infertility were adjusted and matched for both groups. Group 1 included 25 patients who received gonadotropin treatment and letrozole along with gonadotropin-releasing hormone (GnRH) antagonist protocol; group 2 included 25 patients who received gonadotropin treatment along with GnRH antagonist protocol. RESULTS: Total follicle-stimulating hormone (FSH) and daily FSH doses were lower in group 1, although not statistically significant (p > 0.05). The period of ovulation induction was significantly shorter in group 2. While numbers of retrieved oocytes and transferred embryos were lower in group 1, they were not statistically significant (p > 0.05). Number of clinical pregnancies per embryo transfer, number of clinical pregnancies per cycle, and number of ongoing pregnancies (> 16 gestational weeks) were similar in both groups (p > 0.05). CONCLUSIONS: Addition of low-dose letrozole to gonadotropin treatment in GnRH antagonist protocols may result in a lower dose of gonadotropin administration. However, routine clinical practice remains questionable due to no evident positive effect on pregnancy rates.

The effects of gender difference on monocrotaline-induced pulmonary hypertension in rats.

The present study aimed to compare the effect of gender difference on hemodynamic consequences in the development of monocrotaline (MCT)-induced pulmonary hypertension in rat. The effect of antioxidant enzyme systems on the development of pulmonary hypertension mediated by the phytotoxin MCT and the effect of gender on these antioxidant systems were also investigated. For this purpose, the right ventricular pressures (RVPs) and right ventricular/heart weight (HW) ratios were compared between groups and the glutathione (GSH) level and superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities were determined in lung and liver tissue samples of rats. RVP and right ventricular/HW ratios significantly increased in the MCT group compared to the control group. In the MCT group, RVP was significantly higher in males than females. MCT-induced pulmonary hypertension resulted in decreased GSH level, decreased GST and SOD activities and increased CAT activity in lung and liver tissues of both male and female rats. In addition, the lung and liver GSH level and GST and SOD levels were higher in female control rats compared to male control rats. The results of the present study, that antioxidant enzyme activities were different between the groups, highlight the possible role of oxidative stress in the pathogenesis of MCT-induced pulmonary hypertension in rats. Moreover, the lower antioxidant defense capacity of male rats than female rats may be considered as a cause of more aggressive course of MCT-induced pulmonary hypertension in males compared to females.

Relationship between hemorheology and endothelial dysfunction in renal transplant patients receiving calcineurin inhibitors.

BACKGROUND: Calcineurin inhibitors, mainly cyclosporin A (CsA), are associated with endothelial dysfunction in renal transplant recipients (RTRs). Hemorheological disturbances including decreased erythrocyte deformability (ED), increased plasma viscosity and erythrocyte aggregation (EA) have also been reported in CsA-treated RTRs. The aim of this study was to investigate the relationship between hemorheological factors and endothelial dysfunction in CsA- and tacrolimus (Tc)-treated RTRs. METHODS: Thirty-one RTRs and 16 healthy subjects were recruited. The RTR group received either CsA (n = 16) or Tc (n = 15). Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. ED and EA were measured with laser-assisted optical rotational cell analyzer, and plasma viscosity by a cone-plate viscometer. RESULTS: FMD of the CsA group was significantly lower than that of controls (6.3% ± 5.1% vs. 11.9% ± 5.6%, p = 0.024), whereas, there was no significant difference between the Tc group (8.8% ± 5.4%) and controls. At shear stresses ranging between 0.95 and 30 Pa, EDs of the CsA group were significantly lower compared with controls. In the Tc group, the decrease in ED was significant at shear stresses ranging between 0.53 and 5.33 Pa. ED indices did not correlate with FMD in any of the groups. CONCLUSIONS: The degree of endothelial dysfunction and reduction in ED were more remarkable in patients on CsA therapy. Hemorheological factors were not likely to be associated with endothelial dysfunction in RTRs.

Impact of the mandatory age-based single-embryo transfer legislation in Turkey on outcome of in vitro fertilization: a multicentre study.

This study in Turkey evaluated the impact of age-based mandatory single-embryo transfer (SET) legislation with the subsequent increase in frozen-thawed embryo transfer (FT-EU) on pregnancy outcome of in vitro fertilization (IVF) patients. SET, FT-FT and double-embryo transfer were used in 5632 patients after legislation, while traditional IVF and FT-FT approach was used in 6029 patients before legislation. The cumulative pregnancy rate after legislation was slightly lower (38.2%) than before legislation (42.0%) but not significantly so. The single pregnancy rate for SET and traditional IVF were similar between the 2 groups (37.8% versus 28.7%), while multiple pregnancy rates were significantly higher before than after legislation (13.7% versus 0.3%). For FT-ET, the number of cycles was significantly higher after legislation (862 versus 616). SET yielded similar results to traditional IVF. In order to reduce multiple pregnancies without significantly decreasing pregnancy rates, SET might be a successful strategy.

Impact of the mandatory age-based single-embryo transfer legislation in Turkey on outcome of in vitro fertilization:a multicentre study

This study in Turkey evaluated the impact of age-based mandatory single-embryo transfer [SET] legislation with the subsequent increase in frozen-thawed embryo transfer [FT-ET] on pregnancy outcome of in vitrofertilization [IVF] patients. SET, FT-ET and double-embryo transfer were used in 5632 patients after legislation, while traditional IVF and FT-ET approach was used in 6029 patients before legislation. The cumulative pregnancy rate after legislation was slightly lower [38.2%] than before legislation [42.0%] but not significantly so. The single pregnancy rate for SET and traditional IVF were similar between the 2 groups [37.8% versus 28.7%], while multiple pregnancy rates were significantly higher before than after legislation [13.7% versus 0.3%]. For FT-ET, the number of cycles was significantly higher after legislation [862 versus 616]. SET yielded similar results to traditional IVF. In order to reduce multiple pregnancies without significantly decreasing pregnancy rates, SET might be a successful strategy

Relationship between left ventricular diastolic dysfunction and six minute walk test in patients with systemic sclerosis.

OBJECTIVE: The six minute walk test (6MWT) is used for the assessment of functional capacity in pulmonary and cardiovascular diseases. Left ventricular diastolic dysfunction (LVDD) is the most common cardiac abnormality in systemic sclerosis (SSc). The aim of this study was to define the effect of LVDD on 6MWT parameters in patients with SSc. METHODS: We studied 45 (female : male 40 : 5) SSc patients. Patients with obvious conditions that can affect 6MWT distance (6MWD) were excluded. All subjects were evaluated by 6MWT. Additionally, 6MWD of the participants was calculated as the percentage of normal predicted values. LVDD was assessed by using echocardiographic findings and classified into three categories: impaired relaxation, pseudonormal or restrictive. RESULTS: There were 12 (27%) patients with LVDD. SSc patients with LVDD were older than SSc patients without LVDD (50 ± 12 years vs. 41 ± 10 years; P = 0.017). In all, the mean 6MWD was 487.9 ± 98.3 m. The 6MWD was shorter in SSc patients with LVDD as compared to those without LVDD (438.0 ± 94.7 m vs. 506.0 ± 94.5 m; P = 0.039). There was significant difference between the groups regarding the percentage of the predicted 6MWD (74.1 ± 10.1%vs. 82.8 ± 13.1%; P = 0.041). CONCLUSION: The presence of LVDD alters 6MWD in SSc patients. Reduction of 6MWD in a patient with SSc should prompt the investigation of LVDD.

Data filtering with support vector machines in geometric camera calibration.

The use of non-metric digital cameras in close-range photogrammetric applications and machine vision has become a popular research agenda. Being an essential component of photogrammetric evaluation, camera calibration is a crucial stage for non-metric cameras. Therefore, accurate camera calibration and orientation procedures have become prerequisites for the extraction of precise and reliable 3D metric information from images. The lack of accurate inner orientation parameters can lead to unreliable results in the photogrammetric process. A camera can be well defined with its principal distance, principal point offset and lens distortion parameters. Different camera models have been formulated and used in close-range photogrammetry, but generally sensor orientation and calibration is performed with a perspective geometrical model by means of the bundle adjustment. In this study, support vector machines (SVMs) using radial basis function kernel is employed to model the distortions measured for Olympus Aspherical Zoom lens Olympus E10 camera system that are later used in the geometric calibration process. It is intended to introduce an alternative approach for the on-the-job photogrammetric calibration stage. Experimental results for DSLR camera with three focal length settings (9, 18 and 36 mm) were estimated using bundle adjustment with additional parameters, and analyses were conducted based on object point discrepancies and standard errors. Results show the robustness of the SVMs approach on the correction of image coordinates by modelling total distortions on-the-job calibration process using limited number of images.

Conservative management of a patient with endometrial carcinoma desiring fertility: how to inform?

Conservative management of patients with endometrial cancer who desire fertility is becoming widespread in certain circumstances. A 36-year-old women desiring fertility with early-stage endometroid type adenocarcinoma of the endometrium was treated with 160 mg/d megestrol acetate for six months. After confirmation of a normal endometrial biopsy she became pregnant spontaneously. Following an uneventful pregnancy a healthy baby at term was delivered by cesarean section. Definitive surgery was performed. The risks and benefits of this thereupeutic approach are discussed and informing style of the patients emphasized.

Cardioprotection with resveratrol pretreatment: improved beneficial effects over standard treatment in rat hearts after global ischemia.

OBJECTIVE: The major objective of the present study is to evaluate the potential role of resveratrol (RVT), a natural antioxidant found in grapes and red wine, in protecting the myocardium from the deleterious effects of ischemia-reperfusion (I/R) injury using isolated rat hearts. METHODS: Langendorff perfused isolated rat hearts were subjected to 60 min of global ischemia following 60 min of reperfusion. RVT was given according to chronic pretreatment and/or acute treatment protocols. Animals received RVT at the dose of 20 mg/kg via an intragastric tube for 14 days before the experiment and/or at the infusion concentration of 10 microM for 30 min before the onset of ischemia. The myocardial postischemic recovery was compared using hemodynamic data (peak systolic pressure, end diastolic pressure, and +dP/dtmax), coronary flow, biochemical parameters (LDH, CK-MB, cTnI, myoglobin) from coronary effluent, and oxidative stress markers (MDA, GSH, carbonyl) from heart tissue homogenates in each group. RESULTS: RVT pretreatment and treatment protocols have provided increased preservation in myocardial recovery following global ischemia compared to a non-treated group. Furthermore, the ischemic damage of myocardium was significantly lower in chronic pretreated rats than in the acutely treated group. In contrast, no significant difference was observed in cardioprotective effects of RVT between the only pretreated group, and both the pretreated and treated group throughout reperfusion. CONCLUSION: The findings from this study indicate that RVT has potent cardioprotective properties against I/R injury in rat hearts. The study also highlighted that the administration of RVT, as pretreatment, has amplified the beneficial effects over the standard treatment.

A reliable technique of nuclear transplantation for immature mammalian oocytes.

Transplanting a germinal vesicle (GV) to another enucleated oocyte provides a possible way to avoid age-related aneuploidy in metaphase II (MII) oocytes from older women. This study was conducted to examine the efficiency of each step of nuclear transplantation as reflected in the survival and maturation capacity of immature mouse oocytes subjected to this procedure. GV stage oocytes were retrieved from unstimulated ovaries. A GV removed with a small amount of cytoplasm (karyoplast) was transferred subzonally into a previously enucleated oocyte, which was then exposed to direct current to promote fusion. Such reconstituted oocytes were placed in culture to allow maturation, and some that had extruded a first polar body were fixed and processed for chromosome analysis. Each step of nuclear transplantation - survival, enucleation, grafting, and reconstitution - was successful in >90%, with the overall efficiency of reconstitution being 80%. The observation of normal karyotypes confirmed that the procedure did not increase chromosomal aneuploidy. An electrolytic medium, revealed to be superior for the reconstitution procedure, also allowed haploidization of the transplanted nucleus. These findings suggest that this technique can be applied to study the effects of a 'younger' woman's ooplasm on the disjunction of an 'older' woman's chromosomes during meiosis I.

Fertilization and pregnancy outcome with intracytoplasmic sperm injection for azoospermic men.

The evident ability of the intracytoplasmic sperm injection (ICSI) procedure to achieve high fertilization and pregnancy rates regardless of semen characteristics has induced its application with spermatozoa surgically retrieved from azoospermic men. Here, ICSI outcome was analysed in 308 cases according to the cause of azoospermia; four additional cycles were with cases of necrozoospermia. All couples were genetically counselled and appropriately screened. Spermatozoa were retrieved by microsurgical epididymal aspiration or from testicular biopsies. Epididymal obstructions were considered congenital (n = 138) or acquired (n = 103), based on the aetiology. Testicular sperm cases were assessed according to the presence (n = 14) or absence (n = 53) of reproductive tract obstruction. The fertilization rate using fresh or cryopreserved epididymal spermatozoa was 72.4% of 911 eggs for acquired obstructions, and 73.1% of 1524 eggs for congenital cases; with clinical pregnancy rates of 48.5% (50/103) and 61.6% (85/138) respectively. Spermatozoa from testicular biopsies fertilized 57.0% of 533 eggs in non-obstructive cases compared to 80.5% of 118 eggs (P = 0.0001) in obstructive azoospermia. The clinical pregnancy rate was 49.1% (26/53) for non-obstructive cases and 57.1% (8/14) for testicular spermatozoa obtained in obstructive azoospermia, including three established with frozen-thawed testicular spermatozoa. In cases of obstructive azoospermia, fertilization and pregnancy rates with epididymal spermatozoa were higher than those achieved using spermatozoa obtained from the testes of men with non-obstructive azoospermia.

Human glucosamine-6-phosphate isomerase, a homologue of hamster oscillin, does not appear to be involved in Ca2+ release in mammalian oocytes.

Injections of cytosolic preparations from mammalian sperm into oocytes have been shown to trigger calcium [Ca2+]i oscillations and initiate activation of development. Recently, a protein isolated from hamster sperm has been suggested to be involved in the generation of these oscillations and it was named "oscillin." The human homologue of hamster oscillin is glucosamine 6-phosphate isomerase (GPI, EC no. 5.3.1.10), an enzyme so far described to be involved in hexose phosphate metabolism. To assess the role of GPI on Ca2+ signaling, a human recombinant protein was generated in a prokaryotic system and injected into fura-2-dextran-loaded metaphase II (MII) mouse oocytes. Injection of recombinant GPI failed to induce Ca2+ responses in 12/12 injected MII oocytes despite the fact that the recombinant GPI was active as assessed by an enzymatic assay. Injection of buffer (0/6 oocytes) or fructose-6-phosphate, a product of GPI enzymatic reaction (0/5 oocytes), also failed to initiate Ca2+ responses. Conversely, injections of sperm cytosolic factor induced [Ca2+]i oscillations in all 17/17 oocytes. In addition, injection of recombinant GPI or GPI mRNA failed to induce parthenogenetic activation (0/30 oocytes). Immunofluorescence studies using an anti-GPI polyclonal antibody (GK) resulted in localization of GPI to the sperm's equatorial region. Incubation of the GK antibody with sperm extracts failed to block the [Ca2+]i responses induced by these extracts. Moreover, near complete depletion of GPI from sperm fractions by immunoprecipitation did not impair the ability of these fractions to induce [Ca2+]i oscillations. In summary, our results support the role of a sperm cytosolic component(s) in the generation of [Ca2+]i oscillations during mammalian fertilization, although a protein other than GPI/oscillin is likely to be the active calcium releasing factor.