Search PubMed⌕ Search

Biomedical subjects

L Yogev

Publications and source records attributed to L Yogev.

At least 37 records · Page 2Linked to original sources
PubMed2000

Maturation phenotype of Sertoli cells in testicular biopsies of azoospermic men.

The involvement of Sertoli cells in different spermatogenic impairments has been studied by an immunohistomorphometric technique using cytokeratin-18 (CK-18) as a marker for immature Sertoli cells. CK-18 is known to be expressed in Sertoli cells during prenatal and prepubertal differentiation and is normally lost at puberty. Forty-nine azoospermic men were included in the current study. Quantitative measurements on testicular biopsies revealed the highest CK-18 expression in the mixed atrophy biopsies (22 men), a lower expression in the Sertoli cell-only (SCO) biopsies (12 men), and minimal residual staining in the group considered as representing normal spermatogenesis (six obstructive azoospermia patients). The cytokeratin immunopositive-stained tubules were associated either with arrest in spermatogenesis or with SCO. Examination of sections from nine men with microdeletions in the AZF region of the Y chromosome revealed that these men were either negative for CK-18 expression or showed only weak residual staining. This may suggest that the spermatogenic defect in the AZF-deleted men originates in the germ cell and has no impact on Sertoli cell maturation. The cause that determined the spermatogenic defect in the other cases of male infertility with high CK-18 expression may have damaged both the Sertoli and the germ cells.

Adult↗
PubMed2000

Follow-up of sperm concentration and motility in patients with lymphoma.

Lymphomas are a group of diseases, prevalent at reproductive age. Fertility is notoriously reduced among lymphoma patients. This study evaluates pre- and post-treatment semen concentration and motility, and factors associated with semen quality deterioration. We followed-up 33 patients with non-Hodgkin's lymphoma or with Hodgkin's disease during the years 1987-1997 who were referred for semen cryopreservation. Pretreatment semen analysis, and hormonal profile were recorded at diagnosis and at least 1 year after completion of the treatment, and compared. Medical records for disease type, disease stage and treatment protocols were related to long-term sperm outcome. Hormonal concentrations were not predictive of post-treatment sperm concentration. In patients with localized disease, initial sperm concentration and motility tended to be preserved, compared with patients with widespread disease (P: = 0. 016). In Hodgkin's disease patients, treatment with the adriamycin, bleomycin, vinblastine and dacarbazine (ABVD) protocol was superior to the mechloretamine, vincristine, procarbazine and prednisone with ABV protocol regarding germinal toxicity (P: = 0.0008). The post-treatment sperm outcome was better in patients treated with local irradiation than in those who did not undergo irradiation (P: = 0.0027). No predictive tools for post-treatment fertility were found and, therefore, every patient with a lymphoma should have his semen cryopreserved at diagnosis.

Adolescent↗
PubMed2000

[Immunohistochemical identification of testicular germ cells--preliminary report].

The use of testicular spermatozoa for intracytoplasmic sperm injection introduced a new treatment modality for management of male infertility. Since testicular biopsies of non-obstructive azoospermic men are not homogenous in their histological patterns, identification with certainty of focal spermatogenesis might be difficult, particularly in those with small foci of spermatogenesis. We used an immunohistochemical marker of the male germ line, an antibody generated against RBM (RNA-binding-motif), to recognize with high precision the presence of germ cells in the biopsy. Biopsies of 30 men with azoospermia, most with non-obstructive azoospermia and a few with obstruction of the vas deferens, were evaluated. Immunohistochemical staining for RBM protein contributed to the detection and accuracy of the identification of germ cells. Furthermore, this immunohistochemical technique aided the histopathologist to focus on even small foci of spermatogenesis. Absence of the protein expression confirmed the diagnosis of Sertoli-cell-only syndrome. The results indicate that expression of RBM can be a diagnostic marker for identifying the germ cells of small concentrations of spermatogenesis. This method can enhance the accuracy of histopathological evaluation of testicular biopsies that had formerly relied mainly on hematoxylin-and-eosin staining.

Biopsy↗
PubMed1999

Pre-freezing sperm preparation does not impair thawed spermatozoa binding to the zona pellucida.

The present study was conducted to assess the fertilizing potential of frozen-thawed spermatozoa, which were cryopreserved after separation on a Percoll gradient, or washed out of seminal plasma. For this purpose, binding to the zona pellucida and other characteristics of the treated sperm cells were compared with those of cryopreserved spermatozoa from the same original sample which were not manipulated before freezing. Semen specimens were obtained from 80 candidates for sperm donation. Percoll-treated sperm samples compared with the sibling, unprocessed controls had significantly higher values of sperm motility characteristics and per cent of cells with normal morphology after freezing and thawing. Sperm binding ability to the zona pellucida was not statistically different (109 +/- 8.1% and 94 +/- 6.7% in unprocessed and Percoll-treated samples respectively). Sperm specimens processed by washing had significantly higher values for motility characteristics than untreated sibling samples, but no differences were found between the treated and untreated samples for morphology and binding to the zona pellucida (hemizona index of 75 +/- 7.0% and 76 +/- 6.7% in unprocessed and washed samples respectively). These findings suggest that, judged by the binding assay, the aforementioned pre-freezing separation processes have no adverse effect upon the fertilizing potential of the thawed sperm cells. These procedures make it possible to optimize the progressive motile sperm cell concentration of the frozen specimen, which facilitates the storage of samples with good quality, even when the features of the original semen are sub-optimal.

Cell Separation↗
PubMed1999

Genetic evaluation of infertile men.

Recently, microdeletions in the azoospermic factor region of the Y chromosome, in addition to chromosomal anomalies, have been detected in men with azoospermia or severe oligozoospermia. In this study we evaluated the molecular and cytogenetic defects of infertile men. The frequency of Y microdeletions among 105 azoospermic, 28 oligozoospermic and 32 fertile men was tested on lymphocyte DNA using a series of 20 sequence-tagged sites. In addition, microdeletions were evaluated on testicular-derived DNA among 26 azoospermic patients who underwent testicular biopsy and in whom no sperm cells could be identified. Karyotype analysis was performed on 72 of the infertile patients. Deletions were detected in 6.7% azoospermic and 3.6% oligozoospermic men. No deletions were identified among the fertile men. Identical results were obtained with DNA derived either from lymphocytes or testicular tissue. The frequency of chromosomal aberrations in the 72 infertile patients tested (62 azoospermic, 10 oligozoospermic) was 16.6%, with a high percentage of gonosome anomalies. Additional andrological parameters (hormone values, cryptorchidism) failed to identify men at risk for having microdeletions before the test. Our findings support the recommendation to perform genetic defect screening among infertile men before their enrollment in an intracytoplasmic injection/in-vitro fertilization programme.

Adult↗
PubMed1999

Testicular sperm retrieval and cryopreservation prior to initiating ovarian stimulation as the first line approach in patients with non-obstructive azoospermia.

The potency for fertilization and successful implantation was compared between fresh and cryopreserved testicular spermatozoa obtained from the same patient with non-obstructive azoospermia. Spermatozoa cryopreserved at the outset were also evaluated. Non-obstructive azoospermic men (n = 55) underwent testicular sperm extraction (TESE); mature spermatozoa were found in 33 (60%) of them. Of 57 intracytoplasmic sperm injection (ICSI) cycles in 25 patients, 15 used fresh spermatozoa (14 patients, group 1), 24 used the excess spermatozoa cryopreserved after 'fresh' ICSI (11 couples who did not conceive in the 'fresh' cycle, group 2) and 18 cycles used cryopreserved spermatozoa at the outset (11 other patients, group 3). Fertilization, cleavage, embryo quality, implantation and take home baby rates were not significantly different in groups 1 and 2, and 6/14 couples ultimately had healthy babies (42.8% cumulative take home baby rate per TESE). In group 3, neither the fertilization rate, embryo development, pregnancy nor implantation rates per embryo transfer were significantly different from groups 1 and 2. The cumulative delivery and ongoing pregnancy rate in this group was 36. 4%. Cryopreservation did not impair the availability of motile spermatozoa for ICSI. When immotile spermatozoa were injected, however, fertilization rate decreased dramatically. Since criteria for predicting the presence of spermatozoa in the testicular tissue of patients with non-obstructive azoospermia are inadequate, it is suggested that TESE be performed prior to initiating ovarian stimulation.

Adult↗
PubMed1998

Expression of mannose-ligand receptors on human spermatozoa: effect of lecithin and association with sperm binding to the zona pellucida.

OBJECTIVE: To evaluate the change in the expression of mannose-ligand receptors and sperm binding capacity after the incubation of sperm cells with lecithin liposomes. DESIGN: A randomized, blinded-controlled experiment. SETTING: Andrology laboratory at the Lis Maternity Hospital. PATIENT(S): Fifteen fertile sperm donors and 10 subfertile men. INTERVENTION(S): Incubation of sperm samples with either control medium or 1 mg/mL of liposomal lecithin for 2 hours. MAIN OUTCOME MEASURE(S): Expression of mannose-ligand receptors as evaluated by mannosylated bovine serum albumin-fluorescein isothiocyanate and sperm binding to the zona pellucida as evaluated by the hemizona assay. RESULT(S): The mean +/- SE percentages of spermatozoa with patterns I, II, and III were 86% +/- 4.8%, 11% +/- 3.4%, and 3% +/- 1.6%, respectively, after treatment with control medium and 71% +/- 5.7%, 22% +/- 3.5%, and 7% +/- 2.5%, respectively, after treatment with lecithin. The same effect of lecithin was observed in the 10 sperm samples from subfertile men. The mean +/- SE numbers of sperm that bound to hemizonae after treatment with control medium or lecithin were 116 +/- 32.4 and 176 +/- 29.6, respectively. Statistically significant correlations were observed between the shift in patterns II and III and the enhancement of sperm binding after lecithin treatment (r = 0.44 and 0.6, respectively). CONCLUSION(S): Lecithin shifts the expression of mannose-ligand receptors to the capacitated and acrosoine-reacted patterns and enhances the binding capacity of the sperm cells.

Adult↗
PubMed1998

Sperm motility is a major determinant of pregnancy outcome following intrauterine insemination.

PURPOSE: Our purpose was to assess whether one or more sperm parameters have predictive value for the outcome of intrauterine insemination treatment. METHODS: Infertile couples whose normoovulatory and normomechanical female partners underwent superovulation and intrauterine insemination were investigated. The semen profile of the male partner was discounted. In 160 couples, 544 cycles were obtained, resulting in 59 ongoing pregnancies (10.84%/cycle, 36.87%/patient). RESULTS: The only parameter found to be significantly correlated with a positive outcome was the degree of sperm motility following preparation for intrauterine insemination. Close to half (47.5%) of the couples with a very good or an excellent degree of sperm motility conceived, whereas only 8.3% of those patients who had poor or fair sperm motility conceived. None of the semen characteristics, such as volume, count, percentage motility, or percentage normal morphology, were found to correlate with cycle outcome. Although there was a progressive increase in the pregnancy rate with an increase in the total number of motile sperm inseminated, it did not reach significance. Seventy percent of the pregnancies were achieved within a maximum of three treatment cycles. The spermatogram is not accurate enough as a prognostic factor for treatment outcome. CONCLUSIONS: The degree of sperm motility, after appropriate preparation for intrauterine insemination, is the only parameter to be correlated with treatment outcome. For couples with a normal female partner, we suggest a maximum of three treatment cycles of induction of ovulation and intrauterine insemination, whenever good progressive motile sperm is obtained after suitable preparation. For cases with poor sperm progression, we suggest appropriate couple counseling and that an alternative assisted reproduction procedure be taken into consideration.

Adult↗
PubMed1998

Multiple testicular sampling in non-obstructive azoospermia--is it necessary?

Spermatogenesis may be focal in non-obstructive azoospermia. The present study was conducted to determine whether the performance of multiple, rather than a single testicular sample contributes to obtaining spermatozoa in amounts sufficient for fertilization and cryopreservation in non-obstructive, azoospermic patients. Furthermore, the aim was to clarify the significance of location for retrieval from the testis in such cases. Three biopsies were taken from identical locations in 55 testes of 29 men with non-obstructive azoospermia: (i) the rete testis region, ii) the midline, and (iii) the proximal region of the testis. When sperm cells were detected, they were used for intracytoplasmic sperm injection (ICSI), and the remainder were then cryopreserved in as many aliquots as possible (adjusted for ICSI procedure). Spermatozoa were found in 28 testes (50.9%) of 18 men (62.1%). In the testes from which spermatozoa were obtained, they were present in three, two or one locations in 15 (53.6%), five (17.9%) and eight (28.6%) cases respectively. The possibility of finding spermatozoa was not influenced by the location in the testis. Multiple testicular sperm extraction is recommended in cases of non-obstructive azoospermia, since it may enhance diagnostic accuracy of absolute testicular failure and increase the number of sperm cells retrieved.

Adult↗
PubMed1997

Sperm quality in Hodgkin's disease versus non-Hodgkin's lymphoma.

The study was conducted to determine the deleterious effect of lymphoma disease on spermatogenesis and to evaluate the possibility that the disease is mediated primarily by inherent mechanisms in Hodgkin's disease and non-Hodgkin's lymphoma patients. A total of 89 patients with lymphoma disease (Hodgkin's and non-Hodgkin's) were referred for sperm preservation prior to adjuvant treatments. A comparison was made of pre- and post-thaw sperm quality between lymphoma patients and healthy volunteers who applied for sperm donation. This was followed by further assessment of the differences between patients with Hodgkin's disease and non-Hodgkin's lymphoma in terms of sperm variables, clinical parameters and blood hormone concentrations. It was found that patients with lymphoma disease had significantly impaired pre-freeze and post-thaw sperm quality compared with that of healthy volunteers. Patients with non-Hodgkin's lymphoma had spermatozoa of higher quality than patients with Hodgkin's disease. No differences were found in the clinical or hormonal parameters between these two groups. As expected, reduced testicular size and abnormal testicular consistency were correlated with decreased sperm quality. The mere presence of cancer disease has a direct negative effect on spermatogenesis, which is probably not related to incidental side-effects. A variable degree of impairment should be expected with different categories of cancer.

Adolescent↗
PubMed1997

Pregnancy resulting from frozen-thawed embryos achieved by intracytoplasmic injection of cryopreserved sperm cells extracted from an orchidectomized, seminoma-bearing testis, causing obstructive azoospermia.

A clinical pregnancy occurred in a 26-year-old patient after transfer of frozen-thawed embryos had been achieved by intracytoplasmic sperm injection (ICSI) of cryopreserved spermatozoa. These had been obtained from a testis removed due to seminoma. The couple applied to our fertility clinic for sperm cryopreservation before orchidectomy and radiotherapy. Unfortunately the husband was found to be azoospermic upon admission and sperm cells were extracted from the removed testis for use in our ICSI programme. This case represents a new aetiology for obstructive azoospermia that was successfully treated by ICSI. A pregnancy was established, resulting in successful birth.

Adult↗
PubMed1997

Testicular cancer and spermatogenesis.

We retrospectively analysed the characteristics of 54 men with testicular cancer. The group comprised 32 men with pure seminoma and 22 with non-seminoma germ cell tumours (NSGCT). This group was further compared to 190 healthy sperm donor candidates. Sperm quality was found to be higher in the seminoma versus the NSGCT patients in: sperm concentration [50 (0-230) versus 17 (0-288) x 10(6)/ml, P < 0.001], total motile sperm counts (TMC) [57 (0-508) versus 12 (0-854) x 10(6)/ejaculate, P = 0.002], post-thaw forward motile concentration [3 (0-28) versus 1.7 (0-17) x 10(6)/ml, P = 0.003] and motility percentage [20 (0-57) versus 12.5 (0-42) %, P = 0.002]. Serum hormone concentrations did not differ between these two sub-groups, although the follicle stimulating hormone concentrations were higher than normal in both (14.6 +/- 2.5 versus 10.4 +/- 1.4 mIU/ml, P > 0.05). As is well documented, cancer patients were found to have lower sperm quality compared to healthy candidates. The existence of these differences, and the fact that testicular cancer affects spermatogenesis, indicated that the mechanisms involved in the deterioration of sperm quality can, at least partially, be attributed to the type and origin of the malignant cancer. The higher sperm counts in the seminoma group may be related to the fact that the resemblance of the seminoma cells to normal germ cells is greater than that of the NSGCT cells, and therefore they retain a better capacity to function. Due to modern assisted reproductive technologies and micromanipulation achievements, the lower yield of spermatozoa in severe cases is no longer a major obstacle to offering cryopreservation to these patients.

Cryopreservation↗
PubMed1997

Reduction of sperm cholesterol:phospholipid ratio is a possible mechanism for enhancement of human sperm binding to the zona pellucida following incubation with phosphatidylcholine liposomes.

TEST (TES (N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid) and Tris) yolk buffer (TYB) has recently been shown to improve the binding capacity of spermatozoa to zona pellucidae. The present study had two objectives: 1) to elucidate which component(s) of TYB dominates this effect and 2) to define the responsible mechanism. Sperm samples obtained from subfertile men were incubated for 2 h in either TYB or media containing egg yolk lipoproteins or phospholipids. After incubation, sperm binding was tested by the hemizona assay. Yolk lipoprotein-treated spermatozoa bound hemizonae with efficiency equal to that of the spermatozoa incubated in control medium. Conversely, incubation of spermatozoa in media containing either TYB, yolk-phospholipids, or pure phosphatidylcholine (PC) resulted in a 2- to 3-fold increased binding capacity (p < 0.01). A close correlation was found between the effect of yolk-phospholipids and TYB on the binding capacity of the same sperm samples, compared to spermatozoa incubated in control medium. Incubation of spermatozoa in yolk phospholipid medium caused a dose-dependent increase of sperm binding capacity (p < 0.05). Treatment of sperm samples with 1 mg/ml or more of purified PC preparation also resulted in a reduction of the sperm cholesterol:phospholipid molar ratio. Significant correlations between the effects of the treatments on sperm cholesterol: phospholipid molar ratio and sperm binding were obtained with yolk-phospholipids (r = -0.55) or 1 mg/ml purified PC (r = -0.61). We conclude that 1) the enhanced binding capacity of human spermatozoa following TYB treatment is probably due to yolk-phospholipids, mainly egg yolk PC; and 2) it appears that the enhanced binding capacity of human spermatozoa following treatment with egg yolk-containing media may be a result of the reduction of the cholesterol:phospholipid molar ratio in the sperm cells.

Acrosome↗
PubMed1996

Quantitative microscopic changes in the mole rat's accessory sex organs during an annual cycle.

BACKGROUND: The mole rat, Spalax ehrenbergi, is a solitary, aggressive subterranean rodent. The present study summarizes a year-round investigation of morphological changes in the mole rat's accessory sex organs. METHODS: Mole rats maintained in the laboratory were killed after 3 months of acclimation; additional animals trapped in the wild were killed immediately. The accessory sex organs were processed for routine histological examination. Tissues were fixed in Bouin's solution, embedded in paraffin blocks, and stained by hematoxylin-eosin. A systemic sampling approach was used to photomicrograph the tissues for histomorphometric assessment. RESULTS: The volume fraction (Vv, mean +/- SEM) of prostate connective tissue from animals kept in captivity increased significantly in January (0.49 +/- 0.05 mm3/mm3) and April (0.43 +/- 0.04 mm3/mm3) but only 0.26 +/- 0.03 mm3/mm3 in November. In the field group, the Vv of prostate connective tissue was significantly higher in January (0.58 +/- 0.08 mm3/mm3) and April (0.62 +/- 0.08 mm3/mm3) and lower in November (0.44 +/- 0.03 mm3/mm3) and February (0.43 +/- 0.03 mm3/mm3), with a concomitant decrease in prostate tubuli and lumen. The prostate tubuli star volume (v*) in laboratory animals increased in November (0.009 +/- 0.002 mm3) and May (0.09 +/- 0.02 mm3). The same pattern was shown in the field group, with a significant increase in December (0.012 +/- 0.002 mm3) and March (0.007 +/- 0.001 mm3). The Cowper tubuli Vv in the captive animals increased during February (0.24 +/- 0.02 mm3/mm3), with a concomitant reduction in the connective tissue (0.05 +/- 0.02 mm3/mm3). The Cowper tubuli v* in same animals increased in December, April, and July (1.37 +/- 0.18 x 10(-4) mm3, 0.94 +/- 0.10 x 10(-4) mm3, 1.52 +/- 0.20 x 10(-4) mm3, respectively). In field group, a slight decrease in star volume took place from November to May (1.25 +/- 0.16 mm3 to 0.39 +/- 0.05 mm3, respectively). Testosterone levels appeared to be higher in the field group than in the laboratory group. In December the values were 1.62 +/- 0.15 ng/ml in the field group and 0.55 +/- 0.12 ng/ml in the laboratory group, and in May the laboratory group values were 1.66 +/- 0.12 ng/ml. CONCLUSIONS: In captivity and in the field, male mole rats probably undergo an annual cycle of accessory gland tissue structural changes that are correlated with testosterone secretion.

Animals↗
PubMed1995

The use of hemizona assay in the evaluation of the optimal sperm preparation technique.

The objective of the study was to evaluate the benefit of different sperm preparation methods by using the hemizona assay. A total of 58 men admitted to the male infertility clinic for evaluation were tested by routine semen analysis and hemizona assay. Five different techniques (swim-up, TEST-yolk buffer, Percoll, pentoxifylline and progesterone) were used for preparation of sperm suspensions. The effect of these treatments on the sperm-binding capacity using the hemizona assay was assessed. The routine swim-up preparation was used as the reference method. Of the four preparation methods, only the TEST-yolk buffer and pentoxifylline exhibited an overall statistically significant improvement in sperm-binding capacity in comparison with the swim-up preparation method (P = 0.01 and 0.001 respectively). Following preparation with Percoll and progesterone there was no change in the mean value of binding capacity, compared with swim-up. However, examination of the effect of the four treatments on each specimen individually yielded a diversity in the response, e.g. having the capability to enhance, damage or be ineffective in sperm binding capacity. The results support the conclusion that in-vitro sperm preparation methods can affect sperm binding to the zona pellucida. Since there is a diversity in the response of sperm samples to different treatments, the hemizona assay can be used in selecting the optimal sperm preparation method prior to its use for assisted reproductive techniques. This is advocated mainly for the 'male factor' group.

Cell Separation↗