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F Eltes

Publications and source records attributed to F Eltes.

25 records · Page 2Linked to original sources

Interaction between membrane properties and proteins synthesis in reticulocytes - a two step inhibition of protein synthesis by valinomycin.

In this work we consider the differential effect of Valinomycin used at different concentrations both on the protein synthesis of reticulocytes and on 42K exchange. We demonstrate that there is a two step action of this antibiotic. At 10(-6)M and below the drug has no effect on the 42K exchange, but it stops, however reversibly, protein synthesis. At 10(-5)M the drug has a very sharp action on the 42K exchange and stops protein synthesis in an irreversible way. Ribosomal population checked by two ways, sucrose gradient and direct counting on E.M. sections shows that at low concentrations of Valinomycin (10(-8)M to 10(-6)M) there is no breakdown of the polysomes which can be detected by either one of these methods. On the contrary, after short incubation with 10(-5)M of Valinomycin the breakdown of ribosomes is very clear, as evidenced by sucrose gradient analysis. By direct ribosomes clusters counting on E.M. sections this breakdown is seen only after long incubation.

Animals↗

Quantitative ultramorphological analysis of human sperm: fifteen years of experience in the diagnosis and management of male factor infertility.

The advantages of quantitative ultramorphological (QUM) sperm analysis in the diagnosis and treatment of male infertility are presented. The QUM methodology is based on three elements: complementary scanning electron microscopy and transmission electron microscopy observations of 7 sperm cell subcellular organelles (acrosome, postacrosomal lamina, nucleus, neck, axoneme, mitochondrial sheath, and outer dense fibers); systematic classification of the specific ultramorphological malformations into 4 pathological and the normal categories, indicating the morphological state of each subcellular organelle; and comparison between well-defined reference groups with opposite fertility status or treatment conditions. QUM has established 2 indices for the in vivo and in vitro male fertility potential: (1) Natural Fertility Index (NFI), with accurate prediction (97% sensitivity and 90% specificity) of 80% of the male patients; and (2) IVF score, with prediction of 76% of the nonfertilizing and 90% of fertilizing IVF groups. QUM has enabled assessment of ultramorphological indications for varicocele and radiation exposure. Varicocele causes defects in sperm head organelles related to early spermatid development, whereas ionizing radiation causes amorphous head shape. QUM established criteria for specific non-in-vitro therapeutic interventions, including varicocelectomy, follicle-stimulating hormone (FSH) administration, and acupuncture. The varicocele index enabled correct classification of 79 and 89% of patients with and without varicocele. Males with idiopathic impairment of sperm acrosome and nucleus are potential responders to FSH treatment, whereas patients exhibiting low sperm activity are candidates for acupuncture treatment. Patients with a low Natural Fertility Index are recommended for an assisted reproduction technique (ART). based on the ultramorphology of the tail axoneme. Patients who achieved pregnancy following intrauterine insemination or in vitro fertilization and those whose wives conceived only following intracytoplasmic sperm injection were classified with accuracy of 78 and 74%, respectively. QUM sperm analysis is clinically informative, nontraumatic, and cost-effective, and is recommended when the male infertility factor cannot be clearly diagnosed by routine tests prior to first ART trial.

Cell Nucleus↗

Quantitative ultramorphological (QUM) analysis of human sperm: diagnosis and management of male infertility.

The advantages of quantitative ultramorphological (QUM) sperm analysis in the diagnosis and treatment of male infertility are presented. QUM methodology is based on three elements: (1) complementary SEM and TEM observations of 7 sperm cell subcellular organelles: acrosome, postacrosomal lamina, nucleus, neck, axoneme, mitochondrial sheath, and outer dense fibers; (2) systematic classification of the specific ultramorphological malformations into 4 pathological and the normal categories, which indicate the morphological state of each subcellular organelle; and (3) comparison between well-defined reference groups with opposite fertility status or treatment conditions. QUM analysis has enabled the establishment of two indices that optimally express the in vivo and in vitro male fertility potential: The Natural Fertility Index (NFI), which allowed an accurate prediction (97% sensitivity and 90% specificity) of 80% of the naturally fertile and suspected infertile male patients, and the in vitro fertilization (IVF) score, which enabled prediction of 76% of the nonfertilizing and 90% of the fertilizing IVF groups. Validation tests confirmed these data. QUM also enabled assessment of ultramorphological indications for varicocele and radiation exposure: Both male factor etiologies indicated a persistent effect on the natural fertility potential, as expressed by structural changes in the nucleus. Varicocele was found to cause defects in the sperm head organelles related to early spermatid development, whereas ionizing radiation resulted in amorphous head shape. Criteria for specific non-in vitro therapeutic interventions such as varicocelectomy, follicle-stimulating hormone (FSH) administration, and acupuncture treatment were established. A varicocele index, which enabled the correct classification of 79 and 89% of the patients pre- and post-high ligation, respectively, was suggested to be a good indicator for varicocele which affects the fertility potential. Males exhibiting idiopathic impairment of sperm acrosome and nucleus were found to be potential responders to FSH treatment, whereas patients exhibiting low sperm activity proved to be good candidates for acupuncture treatment. Indications for selecting the optimal appropriate assisted reproduction technique (ART) procedure were found: Patients with a low Natural Fertility Index should be recommended for ART. A first choice ART selection should be performed according to an ART index based on the ultramorphological examination of the tail axoneme. The above index enabled correct prediction of 78% of the patients who achieved pregnancy following conventional ART (intrauterine insemination or IVF) and 74% of those whose wives conceived only following intracytoplasmic sperm injection. QUM sperm analysis is clinically informative, nontraumatic, and in the long run also cost-effective. This analysis should be performed when the male infertility factor cannot be clearly diagnosed by routine tests and prior to the first ART trial.

Acrosome↗

Separation of sub-populations of sperm with higher fertility potential from normal and pathological semen by peanut agglutinin.

Incubation of human sperm from semen with counts below 20 x 10(6)/ml with peanut agglutinin (PNA) resulted in agglutination of about 70% of sperm. An inverse correlation was found between non-agglutinating (PNA) sperm and sperm density (r = 0.48, p less than 0.01) and a direct correlation with acrosome-damaged sperm (r = 0.83, p less than 0.001). Binding of 125I-PNA to sperm revealed high, and possibly also low affinity binding sites on sperm from both normozoospermic and oligozoospermic origins. Quantitative transmission electron microscopy analysis revealed that agglutinated, PNA+, sperm had lower frequency of acrosomeless spermatozoa than PNA(-)-sperm (44% versus 77%) and higher fertility score (+0.18 +/- 0.1 and -1.5 +/- 0.87 respectively, p less than 0.01). Removal of PNA- sperm from oligozoospermic semen may increase the fertility score of the remaining sperm.

Cell Separation↗

Relation of human sperm acrosin activity and fertilization in vitro.

The aim of the study described here was to determine the possible contribution of the acrosin activity test to routine semen analysis in enhancing the precision of the prognosis of IVF success in a group of patients in which the contribution of the egg factor to infertility was ruled out (20 cases) compared to a control IVF group (39 cases). Semen analysis, acrosin activity and acrosome ultrastructure were determined for all semen samples. The group with high fertilization rates was comprised of normozoospermic patients while the group with low fertilization rates was comprised of astheno-teratozoospermic patients. The mean acrosin level of the positive IVF group was significantly higher than that of the negative group (51.7 +/- 33.2 and 28.6 +/- 13.7, respectively). Two parameters: per cent motile spermatozoa and acrosin level, were found to have a significant positive correlation with subsequent successful IVF (r = 0.36, P < 0.006; r = 0.37, P < 0.004, respectively); and agenesis of the acrosome was found to have a significant negative correlation (r = -0.33, P < 0.01). The ability of these parameters to correctly predict fertilization success was 59%, with 5% false positive, among which 15.4% was predicted solely by the acrosin level (above 54 microIU 10(6) cells-1) and 23% solely by per cent motile spermatozoa (above 50%). Abnormalities of the acrosome ultrastructure did not contribute further to the correct classification. The apparent clinical benefit of the acrosin level test is discussed.

Acrosin↗

Effect of acupuncture on sperm parameters of males suffering from subfertility related to low sperm quality.

The aim of this prospective controlled study was to assess the effect of acupuncture on the sperm quality of males suffering from subfertility related to sperm impairment. Semen samples of 16 acupuncture-treated subfertile patients were analyzed before and 1 month after treatment (twice a week for 5 weeks). In parallel, semen samples of 16 control untreated subfertile males were examined. Two specimens were taken from the control group at an interval of 2-8 months. The expanded semen analysis included routine and ultramorphological observations. The fertility index increased significantly (p < or = .05) following improvement in total functional sperm fraction, percentage of viability, total motile spermatozoa per ejaculate, and integrity of the axonema (p < or = .05), which occurred upon treatment. The intactness of axonema and sperm motility were highly correlated (corr. = .50, p < or = .05). Thus, patients exhibiting a low fertility potential due to reduced sperm activity may benefit from acupuncture treatment.

Acrosome↗