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PubMed2006

Comparing intracytoplasmic sperm injection and in vitro fertilization in patients with single oocyte retrieval.

OBJECTIVE: To compare the efficacy of intracytoplasmic sperm injection (ICSI) and conventional IVF in patients with favorable and poor sperm parameters in which only a single oocyte was available for insemination. DESIGN: Retrospective analysis. SETTING: University-affiliated IVF center. PATIENT(S): A total of 311 patients (425 cycles) who underwent either stimulated or spontaneous IVF cycles that resulted in single oocyte retrieval. INTERVENTION(S): The ICSI was indicated when fertilization failure was anticipated because of sperm quality or other confounding female factors. MAIN OUTCOME MEASURE(S): Fertilization rates and pregnancy rates (PRs) were analyzed according to the woman's age (< or =39 or >39 years), sperm quality, and mode of insemination. RESULT(S): In patients <39 years old with favorable semen quality, ICSI and standard insemination produced similar fertilization rates (67.1% vs. 75.0%) and PRs (0.0 vs. 8.2%). Conversely, in cases with apparent lower semen quality, ICSI gave a significantly higher fertilization rate (85.4% vs. 44.2%) but no significant difference in PRs (14.6% vs. 4.7%). In patients >39 years old and with favorable semen quality, ICSI and standard insemination produced similar fertilization rates (82.4% vs. 68.4%) and PRs (0.0 vs. 1.1%). The ICSI for lower semen quality, however, produced both higher fertilization rates (84.0% vs. 52%) and higher PRs (8.0% vs. 0). CONCLUSION(S): Our results suggest that in poorly responding patients, semen quality should remain the most important determinant when considering whether to perform ICSI. We have found that the values of 20 x 10(6)/mL and 35% motility are good predictors of success in such patients.

Adult↗
PubMed2006

Distribution of natural radionuclides in the production and use of phosphate fertilizers in Brazil.

The Brazilian phosphate fertilizer is obtained by wet reaction of igneous phosphate rock with concentrated sulphuric acid, giving as final product, phosphoric acid and dehydrated calcium sulphate (phosphogypsum) as by-products. Phosphoric acid is the starting material for triple superphosphate (TSP), single superphosphate (SSP), monoammonium phosphate (MAP) and diammonium phosphate (DAP). The phosphate rock used as raw material presents in its composition radionuclides of the U and Th natural series. Taking this into account, the main aim of this paper is to evaluate the fluxes of natural radionuclides and radioactive disequilibria involved in the Brazilian industrial process of phosphoric acid production; to determine the content of radioactivity in several commercial fertilizers produced by this industry; to estimate their radiological impact in crop soils and the long term exposure due to their application. Radiological characterization of phosphate rock, phosphogypsum and phosphate fertilizers was performed by alpha and gamma spectrometry. The fertilizer samples, which are derived directly from phosphoric acid, MAP and DAP, presented in their composition low activity concentrations for 226Ra, 228Ra and 210Pb. As for U and Th, the concentrations found in MAP and DAP are more significant, up to 822 and 850Bqkg(-1), respectively. SSP and TSP, which are obtained by mixing phosphoric acid with different amounts of phosphate rock, presented higher concentrations of radionuclides, up to 1158Bqkg(-1) for (238)U, 1167Bqkg(-1) for (234)U, 1169Bqkg(-1) for 230Th, 879Bqkg(-1) for 226Ra, 1255Bqkg(-1) for 210Pb, 521Bqkg(-1) for 232Th, 246Bqkg(-1) for 228Ra and 302Bqkg(-1) for 228Th. Long term exposure due to successive fertilizer applications was evaluated. Internal doses due to the application of phosphate fertilizer for 10, 50 and 100 years were below 1mSvy(-1), showing that the radiological impact of such practice is negligible.

Brazil↗
PubMed2006

Accumulation of uranium derived from long-term fertilizer applications in a cultivated Andisol.

The U concentrations in the soils of experimental fields with continuous fertilizer applications and in neighboring non-agricultural soils were determined. The surface soils in the three experimental fields with fertilizer applications contained higher amounts of U compared with the non-agricultural surface soils. The amount of U elevated in the soil was estimated by the vertical profile of U concentration, and an increase of about 200 mg m-2 of U was found in the soils at 0-35 cm depth during a 61-year cultivation period. The estimated value was almost the same as the amount of U added through the fertilizers as calculated from U concentrations in the applied fertilizers. Therefore, almost all the U from the fertilizers would still remain in the upper part of the soils. Chemical extraction results suggested that organic substances and noncrystalline clay minerals in the surface soil should play an important role for accumulation of U derived from the fertilizers.

Agriculture↗
PubMed2006

Epilepsy in India: nuptiality behaviour and fertility.

PURPOSE: The study was conducted to assess the marital status and fertility in adults with epilepsy. METHODS: The study group consisted of 240 subjects with epilepsy aged 15 and above, Unmarried males (m) 55, unmarried females (f) 73 and married males 48, married females 64. Data was collected according to standard protocol regarding age, sex, age at marriage and onset of seizure, effect of epilepsy on marriage, type of seizure and control, fertility pattern and abortions. The study group was followed up for 30 months. The data was compared with latest available state and national data using Student's 't'-test, chi square, Fisher Z-test. RESULTS: The mean age of married subjects was 26.19 + 6.2 years and of the unmarried was 24.94 +/- 7.1 years. People with epilepsy had significantly (p < 0.05) higher mean age at marriage, significantly (p < 0.05) lower rate of marriage (m 46.6% f 46.72%), significantly (p < 0.05) higher divorce rate and withheld marriage. Females compared to males had higher divorce rate (f 5.84%) and withheld marriage (m 5.45% f 10.96%). The marriage rate of subjects with onset of epilepsy in the first decade (m 38.71% f 34.09%) and second decade (m 33.33% f 35.42%) was significantly lower (p < 0.05) than that of subjects with age at onset of epilepsy greater than 20 years (m 66.67% f 71.11%). Subjects with epilepsy not in remission had significantly (p < 0.05) higher mean age at marriage, lower marriage rate and lower fertility per person-year of marriage than those in remission. Majority (95.54%) did not disclose epilepsy before marriage. Total fertility rate (TFR) in males (4.56) and females (5.45) with epilepsy was comparable to general population. Abortions per pregnancy were 4.76%. CONCLUSION: Subjects with epilepsy had lower marriage prevalence rate, delayed marriage (especially females), withheld marriage and higher divorce rate compared to general population. Marriage rate was lower in people with age at onset of epilepsy less than 20 years and in whom seizures were not in remission. Majority of people with epilepsy did not disclose epilepsy before marriage. Though fertility was not affected in people with epilepsy as compared to general population, males had lower fertility than females.

Adolescent↗
PubMed2006

Influence of the dam and sire on size at birth and subsequent growth, milk production and fertility in dairy heifers.

Genetic selection has resulted in larger cows with high milk production potential but a tendency for poor fertility. In multiparous cows fetal development competes for nutrients with concurrent milk production. This study tested the hypotheses that (a) maternal age and milk yield during pregnancy alter calf birth size and (b) birth weight influences subsequent productivity and fertility. Concurrently born Holstein-Friesian heifers (n=65) with multiparous dams and three sires were monitored from birth to the end of their first lactation to assess effects of birth weight on growth, milk production and fertility. Calves were analyzed as three subgroups: low (L), average (A) and high (H) birth weight (BW) calves (n=21-22 per group). LBW calves were born 10 kg lighter than HBW calves and remained significantly lighter throughout the study. They were generally smaller in other measured indices (length, height, girth, ponderal index) between birth and 9 months and were more likely to have older dams (lactations 3-6) with higher peak yields (>42 kg/day). Milk production parameters were indistinguishable between the 3 birthweight groups and metabolic parameters (IGF-I, insulin, glucose) measured around first calving were unaffected. HBW offspring were more likely to have persistent corpora lutea following their first calving and other fertility parameters also tended to be worse. Sire influenced gestation length but not birth size. Sire heritability estimates showed that weight, IGF-I and insulin concentrations after first calving and fertility in the first lactation were all heritable. The results support the hypothesis that high milk production in the dam may predispose to birth of a smaller calf. Smaller birth size did not, however, have any subsequent adverse effects on productivity or fertility in the first lactation and sire was more influential at this stage.

Animals↗
PubMed2006

Genetic variation in fertility of heat-stressed male mice.

The damaging effects of heat stress on male fertility are evident in developing spermatozoa expressed in ejaculates 18-28 days post-stress in mice. Our objectives were to: (1) assess genetic variation in fertility of heat-stressed male mice and (2) determine response to selection for fertility after heat stress in male mice. Mature male mice were exposed to heat stress (35+/-1 degrees C; n=50) or control (21+/-1 degrees C; n=10) conditions for 24h (day 0) and then hemicastrated for tissue collection. Two periods of mating tests followed, period 1 (from days 3 to 11) when no reductions in fertility were anticipated, and period 2 (days 18-26) when variation in fertility was expected. Period 2 pregnant females were sacrificed in late gestation. Males were indexed by multiplying overall mean ovulation rate by pre-implantation survival and number of pregnant period 2 mates. The five highest and five lowest ranking males were identified as heat stress resistant and susceptible, respectively. Resistant males were 61.2units superior in the index, 57.5% greater in pregnancy rate, and 57.6 total fetuses greater than susceptible males. Progeny of resistant sires were superior to progeny of susceptible sires in estimated breeding value by 4.5units for the index, 4.1% for pregnancy rate, and 5.2 fetuses (P<0.0001). Heritability estimates for the index, pregnancy rate, and number of fetuses ranged from 0.09 to 0.13, suggesting male fertility following heat stress is heritable and responds to selection.

Animals↗
PubMed2006

Arachidonate 15-lipoxygenase and ubiquitin as fertility markers in boars.

Accurate semen analysis is an important issue in the swine industry. We evaluated two candidate fertility marker proteins associated with sperm cytoplasmic droplet (CD), including 15-lipoxygenase (15-LOX) and ubiquitin (UBI) in a controlled single-sire artificial insemination (AI) trial. Ejaculates (n=116) were collected from 18 fertile Large White boars monthly for 8 mo, and analyzed by semi-quantitative, densitometry-based Western blotting and flow cytometry with antibodies against 15-LOX and UBI. Data were correlated with farrowing rates (FR) and total numbers of piglets born (TNB) from 1754 AI services by 13 of 18 boars, and compared with a conventional microscopic semen analysis. In semi-quantitative Western blotting, both 15-LOX and UBI were correlated with seasonal changes in the percentage of normal (r=-0.38, P<0.01; r=-0.27, P<0.05, respectively) and CD-bearing spermatozoa (r=0.35, P<0.01; r=0.27, P<0.05, respectively). In flow cytometry, UBI and 15-LOX levels showed seasonal changes coinciding with seasonal changes of FR and TNB, representing 13 boars, 88 ejaculates and 1,232 AI services. There were correlations between flow cytometric values of UBI and FR (r=0.31; P<0.05), adjusted FR (r=0.30; P<0.05), TNB (r=-0.38; P<0.01) and adjusted TNB (r=-0.37; P<0.01). Flow cytometric measurements of 15-LOX correlated negatively with TNB (r=-0.33; P<0.05) and adjusted TNB (r=-0.34; P<0.05). These data suggested that boar fertility estimation could be achieved within a group of fertile boars by the use of objectively measurable fertility markers. Flow cytometry appeared more informative and more practical than semi-quantitative Western blotting. This technology could be further optimized for the selection of the most fertile sires in an artificial insemination program.

Animals↗
PubMed2006

Brief coincubation of gametes in porcine in vitro fertilization: role of sperm:oocyte ratio and post-coincubation medium.

In this study, a short coincubation time of 10 min was used to determine the effect of different sperm:oocyte ratios during in vitro fertilization (IVF), and different periods of post-coincubation in a medium that is not appropriate for IVF, on fertilization parameters. In the first experiment, a total of 1624 in vitro matured oocytes, from 4 replicates, were inseminated with frozen-thawed spermatozoa at different sperm:oocyte ratios (2000, 1500, 1000 and 500 sperm:oocyte) and coincubated for 10 min or 6 h. The oocytes from 10 min of coincubation were washed in IVF medium to remove spermatozoa not bound to the zona pellucida and transferred to another droplet of the same medium (containing no spermatozoa) for 6h. The oocytes from the other group remained with the spermatozoa for 6h. Oocytes from both groups were then cultured in embryo culture medium (IVC) for 12h to assess fertilization parameters. In the second experiment, 1872 in vitro matured oocytes, in 3 replicates were inseminated with frozen-thawed spermatozoa using the same sperm:oocyte ratios as in the first experiment. The oocytes were coincubated for 10 min and transferred directly to IVC medium for 18 h (group A), to IVF medium (containing no sperm) only for 2h and then to IVC medium for 16 h (group B), or to IVF medium (containing no sperm) for 6h and then to IVC medium for 12 h (group C or control). There was an effect of sperm:oocyte ratio on all fertilization parameters in experiment 1. The efficiency of IVF (number of monospermic oocytes/total number inseminated) was higher (P<0.05) for oocytes coincubated with spermatozoa for 10 min and inseminated with 1500 and 1000 sperm:oocyte (35.8+/-3 and 37.6+/-2.7%, respectively) and for those coincubated for 6h with 500 spermatozoa per oocyte (37.2+/-3.1%). In experiment 2, the penetration and efficiency rates obtained in group A were poor (between 3 and 15%) irrespective of the sperm:oocyte ratio. However, in group B the fertilization parameters were similar to the controls and were also affected by the sperm:oocyte ratio. These results demonstrate that coincubation time may be reduced to 10 min to increase the efficiency of fertilization depending on the sperm:oocyte ratio, and that the spermatozoa bound to the zona pellucida require a maximum of 2h in an appropriate medium to penetrate the oocytes.

Animals↗
PubMed2004

Identification of a starfish egg PLC-gamma that regulates Ca2+ release at fertilization.

At fertilization, eggs undergo a cytoplasmic free Ca2+ rise, which is necessary for stimulating embryogenesis. In starfish eggs, studies using inhibitors designed against vertebrate proteins have shown that this Ca2+ rise requires an egg Src family kinase (SFK) that directly or indirectly activates phospholipase C-gamma (PLC-gamma) to produce IP3, which triggers Ca2+ release from the egg's endoplasmic reticulum (ER) [reviewed in Semin. Cell Dev. Biol. 12 (2001) 45]. To examine in more detail the endogenous factors in starfish eggs that are required for Ca2+ release at fertilization, an oocyte cDNA encoding PLC-gamma was isolated from the starfish Asterina miniata. This cDNA, designated AmPLC-gamma, encodes a protein with 49% identity to mammalian PLC-gamma1. A 58-kDa Src family kinase interacted with recombinant AmPLC-gamma Src homology 2 (SH2) domains in a specific, fertilization-responsive manner. Immunoprecipitations of sea urchin egg PLC-gamma using an affinity-purified antibody directed against AmPLC-gamma revealed fertilization-dependent phosphorylation of PLC-gamma. Injecting starfish eggs with the tandem SH2 domains of AmPLC-gamma (which inhibits PLC-gamma activation) specifically inhibited Ca2+ release at fertilization. These results indicate that an endogenous starfish egg PLC-gamma interacts with an egg SFK and mediates Ca2+ release at fertilization via a PLC-gamma SH2 domain-mediated mechanism.

Amino Acid Sequence↗
PubMed2004

Functional domains and temperature-sensitive mutations in SPE-9, an EGF repeat-containing protein required for fertility in Caenorhabditis elegans.

The spe-9 gene is required for fertility in Caenorhabditis elegans and encodes a sperm transmembrane protein with an extracellular domain (ECD) that contains 10 epidermal growth factor (EGF) repeats. Deletion analysis reveals that the EGF repeats and the transmembrane domain are required for fertilization. In contrast, the cytoplasmic region of SPE-9 is not essential for fertilization. Individual point mutations in all 10 EGF motifs uncover a differential sensitivity of these sequences to alteration. Some EGF repeats cannot tolerate mutation leading to a complete lack of fertility. Other EGF repeats can be mutated to create animals with temperature-sensitive (ts) fertility phenotypes. All ts mutations were generated by changing either conserved cysteine or glycine residues in the EGF motifs. For two endogenous ts alleles of spe-9, loss of function at nonpermissive temperatures is not due to protein mislocalization or degradation. Additionally, the proper localization of SPE-9 in sperm is not altered in a genetically interacting fertility mutant (spe-13) or a mutant that affects sperm vesicle-plasma membrane fusion (fer-1). Like the EGF repeats in the Notch/LIN-12/GLP-1 receptors and their ligands, the EGF repeats in SPE-9 may carry out different functions. Because EGF motifs are found in many proteins in different species, similar experimental strategies could be used to generate useful temperature-sensitive mutations in other EGF motif-containing molecules.

Animals↗
PubMed2005

Spatiotemporal characteristics and mechanisms of intracellular Ca(2+) increases at fertilization in eggs of jellyfish (Phylum Cnidaria, Class Hydrozoa).

We have clarified, for the first time, the spatiotemporal patterns of intracellular Ca(2+) increases at fertilization and the Ca(2+)-mobilizing mechanisms in eggs of hydrozoan jellyfish, which belong to the evolutionarily old diploblastic phylum, Cnidaria. An initial Ca(2+) increase just after fertilization took the form of a Ca(2+) wave starting from one cortical region of the egg and propagating to its antipode in all of four hydrozoan species tested: Cytaeis uchidae, Cladonema pacificum, Clytia sp., and Gonionema vertens. The initiation site of the Ca(2+) wave was restricted to the animal pole, which is known to be the only area of sperm-egg fusion in hydrozoan eggs, and the wave propagating velocity was estimated to be 4.2-5.9 mum/s. After a Ca(2+) peak had been attained by the initial Ca(2+) wave, the elevated Ca(2+) gradually declined and returned nearly to the resting value at 7-10 min following fertilization. Injection of inositol 1,4,5-trisphosphate (IP(3)), an agonist of IP(3) receptors (IP(3)R), was highly effective in inducing a Ca(2+) increase in unfertilized eggs; IP(3) at a final intracellular concentration of 12-60 nM produced a fully propagating Ca(2+) wave equivalent to that observed at fertilization. In contrast, a higher concentration of cyclic ADP-ribose (cADPR), an agonist of ryanodine receptors (RyR), only generated a localized Ca(2+) increase that did not propagate in the egg. In addition, caffeine, another stimulator of RyR, was completely without effect. Sperm-induced Ca(2+) increases in Gonionema eggs were severely affected by preinjection of heparin, an inhibitor of Ca(2+) release from IP(3)R. These results strongly suggest that there is a well-developed IP(3)R-, but not RyR-mediated Ca(2+) release mechanism in hydrozoan eggs and that the former system primarily functions at fertilization. Our present data also demonstrate that the spatial characteristics and mechanisms of Ca(2+) increases at fertilization in hydrozoan eggs resemble those reported in higher triploblastic animals.

Animals↗
PubMed2005

The spe-42 gene is required for sperm-egg interactions during C. elegans fertilization and encodes a sperm-specific transmembrane protein.

Fertilization, the union of sperm and egg to form a new organism, is a critical process that bridges generations. Although the cytological and physiological aspects of fertilization are relatively well understood, little is known about the molecular interactions that occur between gametes. C. elegans has emerged as a powerful system for the identification of genes that are necessary for fertilization. C. elegans spe-42 mutants are sterile, producing cytologically normal spermatozoa that fail to fertilize oocytes. Indeed, male mating behavior, sperm transfer to hermaphrodites, sperm migration to the spermatheca, which is the site of fertilization and sperm competition are normal in spe-42 mutants. spe-42 mutant sperm make direct contact with oocytes in the spermatheca, suggesting that SPE-42 plays a role during sperm-egg interactions just prior to fertilization. No other obvious defects were observed in spe-42 mutant worms. Cloning and sequence analysis revealed that SPE-42 is a novel predicted 7-pass integral membrane protein with homologs in many metazoan species, suggesting that its mechanism of action could be conserved.

Amino Acid Sequence↗
PubMed2004

Female sexual behavior, but not sex skin swelling, reliably indicates the timing of the fertile phase in wild long-tailed macaques (Macaca fascicularis).

The extent to which catharrine primate males are able to discern the fertile phase during the female ovarian cycle under natural conditions is still debated. In a recent study, we showed that wild male long-tailed macaques are able to detect the fertile phase, but the cues males used to assess female reproductive status remained unclear. In the present study, we tested female sex skin swelling and specific female behaviors for their reliability in signaling the fertile phase, as determined by measurement of fecal estrogens (E) and progestogens (P) during nine ovulatory cycles in seven free-ranging females. We found that changes in sex skin swellings showed a significant positive correlation to the E/P ratio, but swelling size did not significantly differ between cycle phases. In contrast, the frequency of two of the tested female behaviors, namely initiation of sexual interactions and reaching back for the male during copulation, was not only correlated with female reproductive hormones, but was significantly elevated during the fertile phase compared to nonfertile phases of the cycle. We thus conclude that female sex skin swelling does not reliably indicate the timing of the fertile phase in long-tailed macaques, whereas certain female behaviors do. Since cycles differed considerably in the number of males with which females had sexual interactions as well as in the number of sexual interactions with dominant males, the signaling character of these specific female behaviors appears to be robust against inconsistencies in these social variables. Female behavior might therefore play an important role in the recognition of the fertile phase by male macaques under natural conditions.

Anal Canal↗
PubMed1992

Electroejaculation in combination with in vitro fertilization and gamete micromanipulation for treatment of anejaculatory male infertility.

OBJECTIVE: Failure to ejaculate may be overcome by use of electroejaculation. However, such semen samples are often unsuitable for therapies like intrauterine insemination. The combination of electroejaculation with in vitro fertilization, including gamete micromanipulation, should improve chances of fertilization and pregnancy in such cases. STUDY DESIGN: Within a private infertility clinic electroejaculation in combination with intrauterine insemination was carried out in 18 cycles (10 couples). Four couples went on to receive therapy by electroejaculation plus in vitro fertilization, along with six other couples (15 cycles total) with semen too poor for intrauterine insemination. RESULTS: One term pregnancy arose in the electroejaculation-intrauterine insemination group, and one term pregnancy plus one continuing pregnancy arose from two couples (three cycles) who underwent in vitro fertilization with conventional insemination after electroejaculation. Six couples (nine cycles) had embryos arising only from gamete micromanipulation transferred, and this yielded two term pregnancies, one spontaneous abortion, and a biochemical pregnancy. Two couples (three cycles) failed to achieve fertilization even with micromanipulation; however, donor-inseminated eggs gave rise to two term pregnancies and one continuing pregnancy in these patients. CONCLUSIONS: This report confirms the feasibility of in vitro fertilization in conjunction with electroejaculation and extends the therapy to incorporate gamete micromanipulation.

Adult↗
PubMed1996

In vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination: efficacy and potential health hazards on babies delivered.

OBJECTIVE: The purpose of this article was to review the efficacy and potential hazards of assisted conception. STUDY DESIGN: A review of pertinent scientific articles published in English was done. RESULTS: There are no adequate prospective, randomized, controlled, or comparative studies of sufficient power on the efficacy of in vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination in well-defined infertile couples. In vitro fertilization can overcome tubal sterility. The pregnancy per cycle is 19.8% and delivery per cycle is 16.0% for in vitro fertilization (all indications) and 29.5% and 19.8%, respectively, for gamete intrafallopian transfer. In limited prospective studies, in vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination have similar fecundity. Multiple births from in vitro fertilization and gamete intrafallopian transfer are increased, whereas preterm labor and low-birth-weight babies are significantly more common, even in singletons. CONCLUSION: The efficacy or relative superiority of IVF, gamete intrafallopian transfer, and superovulation with intrauterine insemination in nontubal subfertility remains to be shown by properly designed, prospective, randomized, controlled, or comparative studies. Therefore less invasive and less expensive methods such as expectant management or superovulation with intrauterine insemination should be used before embarking on in vitro fertilization and gamete intrafallopian transfer. Further studies on the outcome of babies delivered after assisted conception are required.

Female↗
PubMed1999

The TwoDay Algorithm: a new algorithm to identify the fertile time of the menstrual cycle.

Women who monitor their fertility signs and recognize when they are fertile can use this knowledge to conceive or to avoid pregnancy. Studies have shown that there is a rather small fertile window of several days during each menstrual cycle. Established methods of identifying the fertile window, such as the Ovulation and the Symptothermal methods of Natural Family Planning, can be very effective in helping couples avoid pregnancy. A new algorithm for identifying the fertile window has been developed, based on monitoring and recording of cervical secretions. The TwoDay Algorithm appears to be simpler to teach, learn, and use than current natural methods. A large existing data set from a World Health Organization study of the Ovulation Method, along with Natural Family Planning charts from women using the Ovulation Method and the Symptothermal Method, were used to determine the potential effectiveness of the TwoDay Algorithm in identifying the fertile window. Results suggest that the algorithm can be an effective alternative for low literacy populations or for programs that find current Natural Family Planning methods too time consuming or otherwise not feasible to incorporate into their services. Further studies are needed to determine the efficacy of the TwoDay Algorithm in avoiding pregnancy and to assess its acceptability to users and providers.

Adult↗
PubMed2003

Function of a sea urchin egg Src family kinase in initiating Ca2+ release at fertilization.

Egg activation at fertilization requires the release of Ca(2+) from the egg's endoplasmic reticulum, and recent evidence has indicated that a Src family kinase (SFK) may function in initiating this signaling pathway in echinoderm eggs. Here, we identify and characterize a SFK from the sea urchin Strongylocentrotus purpuratus, SpSFK1. SpSFK1 RNA is present in eggs, and an antibody made against a SpSFK1 peptide recognizes an approximately 58-kDa egg membrane-associated protein in eggs of S. purpuratus as well as another sea urchin Lytechinus variegatus. Injection of both species of sea urchin eggs with dominant-interfering Src homology 2 domains of SpSFK1 delays and reduces the release of Ca(2+) at fertilization. Injection of an antibody against SpSFK1 into S. purpuratus eggs also causes a small increase in the delay between sperm-egg fusion and Ca(2+) release. In contrast, when injected into eggs of L. variegatus, this same antibody has a dramatic stimulatory effect: it causes PLCgamma-dependent Ca(2+) release like that occurring at fertilization. Correspondingly, in lysates of L. variegatus eggs, but not S. purpuratus eggs, the antibody stimulates SFK activity. Injection of L. variegatus eggs with another antibody that recognizes the L. variegatus egg SFK also causes PLCgamma-dependent Ca(2+) release like that at fertilization. These results indicate that activation of a Src family kinase present in sea urchin eggs is necessary to cause Ca(2+) release at fertilization and is capable of stimulating Ca(2+) release in the unfertilized egg via PLCgamma, as at fertilization.

Amino Acid Sequence↗
PubMed2001

Dramatic declines in implantation and pregnancy rates in patients who undergo repeated cycles of in vitro fertilization with blastocyst transfer after one or more failed attempts.

OBJECTIVE: To compare the outcome of second and third cycles of in vitro fertilization with blastocyst transfer to the outcome of first attempts at IVF with blastocyst transfer. DESIGN: Retrospective study. SETTING: Private ART center. PATIENT(S): Three hundred and four patients undergoing treatment with in vitro fertilization with blastocyst transfer, 87 of which underwent at least one cycle of re-treatment after failing to achieve pregnancy in their first cycle. INTERVENTION(S): Bipronucleate oocytes were grown for up to 144 hours and subsequently transferred when at least one embryo attained the expanded blastocyst stage. MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): Pregnancy rates per retrieval were significantly higher for patients undergoing their first cycle of in vitro fertilization with blastocyst transfer (36%) compared to those undergoing their second (19%) or their third (9%) cycles of treatment. Implantation rates per embryo were also higher for first cycles of in vitro fertilization with blastocyst transfer (30%) compared to second (18%) or third cycles (8%). CONCLUSION(S): Pregnancy and implantation rates decline dramatically in repeated cycles of in vitro fertilization with blastocyst transfer following one or more unsuccessful cycles of in vitro fertilization with blastocyst transfer.

Adult↗