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PubMed2003

Identification of the human and bovine ATP:Cob(I)alamin adenosyltransferase cDNAs based on complementation of a bacterial mutant.

In humans, deficiencies in coenzyme B12-dependent methylmalonyl-CoA mutase (MCM) lead to methylmalonyl aciduria, a rare disease that is often fatal in newborns. Such deficiencies can result from inborn errors in the MCM structural gene or from mutations that impair the assimilation of dietary cobalamins into coenzyme B12 (Ado-B12), the required cofactor for MCM. ATP:cob(I)alamin adenosyltransferase (ATR) catalyzes the terminal step in the conversion of cobalamins into Ado-B12. Substantial evidence indicates that inherited defects in this enzyme lead to methylmalonyl aciduria, but the corresponding ATR gene has not been identified. Here we report the identification of the bovine and human ATR cDNAs as well as the corresponding human gene. A bovine liver cDNA expression library was screened for clones that complemented an ATR-deficient bacterial strain for color formation on aldehyde indicator medium, and four positive clones were isolated. The DNA sequences of two clones were determined and found to be identical. Sequence similarity searching was then used to identify a homologous human cDNA (89% identity) and its corresponding gene that is located on chromosome XII. The bovine and human cDNAs were independently cloned and expressed in Escherichia coli. Enzyme assays showed that expression strains produced 87 and 98 nmol/min/mg ATR activity, respectively. These specific activities are in line with values reported previously for bacterial ATR enzymes. Subsequent studies showed that the human cDNA clone complemented an ATR-deficient bacterial mutant for Ado-B12-dependent growth on 1,2-propanediol. This demonstrated that the human ATR is active under physiological conditions albeit in a heterologous host. In addition, Western blots were used to show that ATR expression is altered in cell lines derived from cblB methylmalonyl aciduria patients compared with cell lines from normal individuals. We propose that inborn errors in the human ATR gene identified here result in methylmalonyl aciduria. The identification of genes involved in this disorder will allow improvements in the diagnosis and treatment of this serious disease.

Adenosine Triphosphate↗
PubMed2003

Hydroxylation-induced stabilization of the collagen triple helix. Further characterization of peptides with 4(R)-hydroxyproline in the Xaa position.

4(R)-Hydroxyproline in the Yaa position of the -Gly-Xaa-Yaa-repeated sequence of collagen plays a crucial role in the stability of the triple helix. Since the peptide (4(R)-Hyp-Pro-Gly)10 does not form a triple helix, it was generally believed that polypeptides with a -Gly-4(R)-Hyp-Yaa-repeated sequence do not form a triple helix. Recently, we found that acetyl-(Gly-4(R)-Hyp-Thr)10-NH2 forms a triple helix in aqueous solutions. To further study the role of 4(R)-hydroxyproline in the Xaa position, we made a series of acetyl-(Gly-4(R)-Hyp-Yaa)10-NH2 peptides where Yaa was alanine, serine, valine, and allo-threonine. We previously hypothesized that the hydroxyl group of threonine might form a hydrogen bond to the hydroxyl group of 4(R)hydroxyproline. In water, only the threonine- and the valine-containing peptides were triple helical. The remaining peptides did not form a triple helix in water. In 1,2- and in 1,3-propanediol at 4 degrees C, all the soluble peptides were triple helical. From the transition temperature of the triple helices, it was found that among the examined residues, threonine was the most stable residue in the acetyl-(Gly-4(R)-Hyp-Yaa)10-NH2 peptide. The transition temperatures of the valine- and allo-threonine-containing peptides were 10 degrees lower than those of the threonine peptide. Surprisingly, the serine-containing peptide was the least stable. These results indicate that the stability of these peptides depends on the presence of a methyl group as well as the hydroxyl group and that the stereo configuration of the two groups is essential for the stability. In the threonine peptide, we hypothesize that the methyl group shields the interchain hydrogen bond between the glycine and the Xaa residue from water and that the hydroxyl groups of threonine and 4(R)hydroxyproline can form direct or water-mediated hydrogen bonds.

Circular Dichroism↗
PubMed2005

Sphingosine kinase 2 is required for modulation of lymphocyte traffic by FTY720.

Immunotherapeutic drugs that mimic sphingosine 1-phosphate (S1P) disrupt lymphocyte trafficking and cause T helper and T effector cells to be retained in secondary lymphoid tissue and away from sites of inflammation. The prototypical therapeutic agent, 2-alkyl-2-amino-1,3-propanediol (FTY720), stimulates S1P signaling pathways only after it is phosphorylated by one or more unknown kinases. We generated sphingosine kinase 2 (SPHK2) null mice to demonstrate that this kinase is responsible for FTY720 phosphorylation and thereby its subsequent actions on the immune system. Both systemic and lymphocyte-localized sources of SPHK2 contributed to FTY720 induced lymphopenia. Although FTY720 was selectively activated in vivo by SPHK2, other S1P pro-drugs can be phosphorylated to cause lymphopenia through the action of additional sphingosine kinases. Our results emphasize the importance of SPHK2 expression in both lymphocytes and other tissues for immune modulation and drug metabolism.

Animals↗
PubMed2006

Probing of HIV-1 integrase/DNA interactions using novel analogs of viral DNA.

The specific activity of the human immunodeficiency virus, type 1 (HIV-1), integrase on the viral long terminal repeat requires the binding of the enzyme to certain sequences located in the U3 and U5 regions at the ends of viral DNA, but the determinants of this specific DNA-protein recognition are not yet completely understood. We synthesized DNA duplexes mimicking the U5 region and containing either 2'-modified nucleosides or 1,3-propanediol insertions and studied their interactions with HIV-1 integrase, using Mn2+ or Mg2+ ions as integrase cofactors. These DNA modifications had no strong effect on integrase binding to the substrate analogs but significantly affected 3'-end processing rate. The effects of nucleoside modifications at positions 5, 6, and especially 3 strongly depended on the cationic cofactor used. These effects were much more pronounced in the presence of Mg2+ than in the presence of Mn2+. Modifications of base pairs 7-9 affected 3'-end processing equally in the presence of both ions. Adenine from the 3rd bp is thought to form at least two hydrogen bonds with integrase that are crucial for specific DNA recognition. The complementary base, thymine, is not important for integrase activity. For other positions, our results suggest that integrase recognizes a fine structure of the sugar-phosphate backbone rather than heterocyclic bases. Integrase interactions with the unprocessed strand at positions 5-8 are more important than interactions with the processed strand for specific substrate recognition. Based on our results, we suggest a model for integrase interaction with the U5 substrate.

Base Pairing↗
PubMed2006

Analysis of the Salmonella typhimurium proteome through environmental response toward infectious conditions.

Salmonella enterica serovar Typhimurium (also known as Salmonella typhimurium) is a facultative intracellular pathogen that causes approximately 8,000 reported cases of acute gastroenteritis and diarrhea each year in the United States. Although many successful physiological, biochemical, and genetic approaches have been taken to determine the key virulence determinants encoded by this organism, the sheer number of uncharacterized reading frames observed within the S. enterica genome suggests that many more virulence factors remain to be discovered. We used a liquid chromatography-mass spectrometry-based "bottom-up" proteomic approach to generate a more complete picture of the gene products that S. typhimurium synthesizes under typical laboratory conditions as well as in culture media that are known to induce expression of virulence genes. When grown to logarithmic phase in rich medium, S. typhimurium is known to express many genes that are required for invasion of epithelial cells. Conversely stationary phase cultures of S. typhimurium express genes that are needed for both systemic infection and growth within infected macrophages. Lastly bacteria grown in an acidic, magnesium-depleted minimal medium (MgM) designed to mimic the phagocytic vacuole have been shown to up-regulate virulence gene expression. Initial comparisons of protein abundances from bacteria grown under each of these conditions indicated that the majority of proteins do not change significantly. However, we observed subsets of proteins whose expression was largely restricted to one of the three culture conditions. For example, cells grown in MgM had a higher abundance of Mg(2+) transport proteins than found in other growth conditions. A second more virulent S. typhimurium strain (14028) was also cultured under these same growth conditions, and the results were directly compared with those obtained for strain LT2. This comparison offered a unique opportunity to contrast protein populations in these closely related bacteria. Among a number of proteins displaying a higher abundance in strain 14028 were the products of the pdu operon, which encodes enzymes required for propanediol utilization. These pdu operon proteins were validated in culture and during macrophage infection. Our work provides further support for earlier observations that suggest pdu gene expression contributes to S. typhimurium pathogenesis.

Amino Acid Sequence↗
PubMed2002

Taxonomy of the glycerol fermenting clostridia and description of Clostridium diolis sp. nov.

Six Clostridium strains which ferment glycerol to 1,3-propanediol were tested for their taxonomic and phylogenetic relatedness. All but one were known as C butyricum. By physiological tests, 16S rDNA sequences and fatty acid composition two groups were distinguished. The first comprised the strains VPI 3266, DSM 2478 and DSM 523 (C. "kainantoi") and was consistent with the type strain of C. butyricum in almost all characters. The second group comprising the strains DSM 5430, DSM 5431 and E5 was related to C. beijerinckii. The 16S rDNAs of these strains were almost identical with that of the type strain of C. beijerinckii, DSM 791. The DNA-DNA hybridization value of DSM 5431 and ES with C. beijerinckii DSM 791 was markedly but not decisively lower (67 and 72%, respectively). However, there were significant physiological differences to C. beijerinckii which suggested to describe the strains as a separate species, Clostridium diolis with strain SH1 (= DSM 5431) as the type strain. The new species is distinguished from C. beijerinckii, which requires complex nutrients, by its ability to grow in glucose mineral medium with biotin as the only growth factor and by differences in substrate utilization. "C. kainantoi" Takeda and Matsui was recognized as a later synonym of C. butyricum.

Base Sequence↗
PubMedDate not supplied

Fetal calf serum versus human serum: ultrastructural evaluation of protein support influence on human ovarian tissue cryopreservation.

The aim of this study was to examine the effect of the different protein supports in the cryopreservation solution on improving human ovarian tissue preservation after frozen-thawed procedures. Biopsies of ovarian cortical tissue were obtained from 14 subjects. All specimens were cryopreserved using a slow freezing/rapid thawing method in a solution consisting of propanediol and sucrose in different proportions of 3 protein supports: 30% human serum (HS) (solution A), 20% HS (solution B), or 20% fetal calf serum (solution C). After thawing, 191 follicles and a total of 70 samples were analyzed using transmission electron microscopy (TEM). The post-thaw preservation rate of the follicles in solution A was significantly higher with respect to solution C (p < 0.05). Unlike the follicles, the stromal cell morphology was not affected by any of the solutions investigated. By comparing stromal morphology and the patient age, it was found that HS better preserved the tissue in patients over 20 years of age with respect to younger ones, which showed a wider variability in ovarian preservation. TEM evaluation showed that 30% HS is more suitable for human ovarian tissue cryopreservation, and research should be focused on defining cryopreservation protocols specific to young patients.

Adolescent↗
PubMedDate not supplied

Predominant K-ras codon 12 G --> A transition in chemically induced lung neoplasms in B6C3F1 mice.

Based on long-term toxicity and carcinogenicity studies in B6C3F1 mice conducted by the National Toxicology Program, 2,2-Bis(bromomethyl)-1,3-propanediol (BMP) and tetranitromethane (TNM) have been identified as carcinogens. Following 2 yr of exposure to 312, 625, or 1,250 ppm BMP in feed, or exposure to 0.5 or 2 ppm TNM by inhalation, increased incidences of lung neoplasms were observed in B6C3F1 mice at all exposure concentrations compared to unexposed mice. The present study characterizes genetic alterations in the K-ras protooncogene in BMP- and TNM-induced lung neoplasms, respectively, and compares the findings to spontaneous lung neoplasms from corresponding control mice. The frequencies of the K-ras mutations were 57% (29/51) in BMP-induced lung neoplasms compared to 15% (3/20) in lung neoplasms from dosed feed control mice, and 54% (14/26) in TNM-induced lung neoplasms compared to 60% (3/5) in lung neoplasms from inhalation control mice. G --> A transitions at the second base of the K-ras codon 12 (GGT --> GAT) were the most frequent pattern of K-ras mutations identified in BMP-induced (20/29) and TNM-induced lung neoplasms (13/14), which differed from the mutational patterns identified in the lung neoplasms from unexposed control mice. These results indicate that mutations in the K-ras gene are involved in B6C3F1 lung carcinogenesis following BMP- and TNM-exposure, and the high frequency and specificity of the ras mutation profile in lung neoplasms (G --> A transition) may be due to in vivo genotoxicity by the parent compounds or their metabolites.

Animals↗
PubMedDate not supplied

Analytical methods for the determination of 3-chloro-1,2-propandiol and 2-chloro-1,3-propandiol in hydrolysed vegetable protein, seasonings and food products using gas chromatography/ion trap tandem mass spectrometry.

The EC Scientific Committee for Foods and more recently the Food Advisory Committee in the UK have proposed that levels of 3-chloro-1,2-propanediol (3-MCPD) in foods and ingredients should be reduced to the lowest possible. This paper reports on the development of methods for the determination of parts-per-billion (microgram/kg) levels of 3-MCPD in hydrolysed vegetable protein (HVP), flour, bread, meat and starch products using gas chromatography/ion-trap tandem mass spectrometry (GC/ITMS/MS). Mass spectrometer conditions for detecting 3-MCPD and the stable isotope internal standard (3-chloro-1,2-propandiol-d7) were established. Candidate extraction methods were initially evaluated for recovery and repeatability by spiking selected commodities at a level of 100 micrograms/kg. Extracts of ingredients and foods prepared by the candidate extraction methods were examined by GC/ITMS/MS using samples spiked at a level of 25 micrograms/kg. The results showed that detection limits of between 3 and 5 micrograms/kg could be achieved for all commodities.

Bread↗
PubMed1999

Evaluation of different types of end-capping modifications on the stability of oligonucleotides toward 3'- and 5'-exonucleases.

Synthetic oligonucleotides are increasingly used because of their potential activity as regulators of gene expression. One of their major drawbacks is instability toward nucleases, in particular exonucleases. In this article, we studied some terminal modifications that can enhance exonuclease resistance, such as end-capping with alkylic chains (1,3-propanediol and 1,6-hexanediol), and with a modified nucleotide (2',3'-secouridine). These compounds were compared with the parent (natural) oligodeoxynucleotide and with different analogs containing a progressive number of phosphorothioate linkages. The resistance toward SVPDE and CSPDE (a 3'- and a 5'-exonuclease) was assessed, in vitro, by two independent techniques, UV and HPLC. Our results showed that the stability of all the modified oligonucleotides was at least 12 times that of the parent compound.

Animals↗
PubMed2003

The uptake, distribution, metabolism, and excretion of methyl tertiary-butyl ether inhaled alone and in combination with gasoline vapor.

The purpose of these studies was to evaluate the tissue uptake, distribution, metabolism, and excretion of methyl tertiary-butyl ether (MTBE) in rats and to determine the effects of coinhalation of the volatile fraction of unleaded gasoline on these parameters. Male F344 rats were exposed nose-only once for 4 h to 4, 40, or 400 ppm 14C-MTBE and to 20 and 200 ppm of the light fraction of unleaded gasoline (LFG) containing 4 and 40 ppm 14C-MTBE, respectively. To evaluate the effects of repeated inhalation of LFG on the fate of inhaled MTBE, rats were exposed for 7 consecutive days to 20 and 200 ppm LFG followed on d 8 by exposure to LFG containing 14C-MTBE. Three subgroups of rats were included for evaluation of respiratory parameters, rates and routes of excretion, and tissue distribution and elimination. MTBE and its chief metabolite, tertiary-butyl alcohol, were quantitated in blood and kidney (immediately after exposure), and the major urinary metabolites, 2-hydroxyisobutyric acid and 2-methyl-1,2- propanediol, were identified and quantified in urine. Inhalation of MTBE alone or as a component of LFG had no concentration-dependent effect on respiratory minute volume. The initial body burdens (IBBs) of MTBE equivalents achieved after 4 h of exposure to MTBE did not increase linearly with exposure concentration. MTBE equivalents rapidly distributed to all tissues examined, with the largest percentages distributed to liver. Between 40 and 400 ppm, there was a significant reduction in percentage of the IBB present in the major organs examined, both immediately and 72 h after exposure. At 400 ppm, the elimination rates of MTBE equivalents from tissues changed significantly. Furthermore, at 400 ppm there was a significant decrease in the elimination half-time of volatile organic compounds (VOCs) in breath and a significant increase in the percentage of the IBB of MTBE equivalents eliminated as VOCs in breath. LFG coexposure significantly decreased the percentage of the MTBE equivalent IBBs in tissues and increased rates of elimination of MTBE equivalents. The study results indicate that the uptake and fate of inhaled MTBE are altered upon increasing exposure levels from 4 to 400 ppm, suggesting that toxic effects observed previously upon repeated inhalation of concentrations of 400 ppm or greater may not necessarily be linearly extrapolated to effects that might occur at lower concentrations. Furthermore, coexposure to LFG, whether acute or repeated, decreases tissue burdens of MTBE equivalents and enhances the elimination rate of MTBE and its metabolites, thereby potentially reducing the toxic effects of the MTBE compared to when it is inhaled alone.

Air Pollutants↗
PubMed1988

Metabolism of nephrotoxic isopropylcyclohexane in male Fischer 344 rats.

The metabolism of isopropylcyclohexane and associated renal pathology were evaluated in male Fischer 344 rats exposed by oral gavage. The rats experienced moderate proximal tubular damage similar to that produced by acyclic, branched-chain hydrocarbons. The urinary metabolites of isopropylcyclohexane included cis-4-isopropylcyclohexanol, trans-4-isopropylcyclohexanol, 2-cyclohexylpropanoic acid, 2-cyclohexyl-1,3-propanediol, 2t-hydroxy-4t-isopropylcyclohexanol, 2c-hydroxy-4c-isopropyl-cyclohexanol, and 2c-hydroxy-4t-isopropylcyclohexanol. The extent and preferred sites of oxidative metabolism of nephrotoxic hydrocarbons could potentially prove useful in elucidating the pathogenic mechanisms.

Administration, Oral↗
PubMed1976

Isoelectric focusing of alkaline phosphatase isoenzymes in polyacrylamide gels. Use of Triton X-100 and improved staining technic.

The examination of alkaline phosphatase isoenzymes by means of isoelectric focusing in polyacrylamide gel rods using the apparatus and focusing method of Righetti and Drysdale is discussed. A simultaneous coupling procedure using alpha-naphthyl phosphate and fast blue salt R in 2-amino-2-methyl-1,3-propanediol buffer, pH 9.68, containing MgCl2 and ZnSO4 proved sensitive for developing the enzyme bands. Also discussed are the effects seen with the incorporation of Triton X100 into the gel and sample mixtures. Enzyme, which remained at the top of the gel without using this detergent, entered the gel easily with the addition of Triton X-100 into the application solution. Incorporation of Triton into the gel matrix resulted in some enzyme band patterns that showed distinct differences from gels containing no Triton.

Acrylamides↗
PubMed2004

A specific receptor site for glycerol, a new sweet tastant for Drosophila: structure-taste relationship of glycerol in the labellar sugar receptor cell.

Glycerol, a linear triol, is a sweet tastant for mammals but it has not previously been recognized to stimulate the sense of taste in insects. Here we show by electrophysiological experimentation that it effectively stimulates the labellar sugar receptor cell of Drosophila. We also show that in accord with the electrophysiological observations, the behavioral feeding response to glycerol is dose dependent. 3-Amino-1,2-propanediol inhibited the response of the sugar receptor cell to glycerol, specifically and competitively, while it had almost no effect on responses to sucrose, D-glucose, D-fructose and trehalose. In the null Drosophila mutant for the trehalose receptor (DeltaEP19), the response to glycerol showed no change, in sharp contrast with a characteristic drastic decrease in the response to trehalose. The glycerol concentration-response curves for I-type and L-type labellar hairs were statistically indistinguishable, while those for sucrose, D-glucose, D-fructose and trehalose were clearly different. These all indicate the presence of a specific receptor site for glycerol. The glycerol site was characterized by comparing the effectiveness of various derivatives of glycerol. Based on this structure-taste relationship of glycerol, a model is proposed for the glycerol site including three subsites and two steric barriers, which cannot accommodate carbon-ring containing sugars such as D-glucose.

Animals↗
PubMed2002

Crystal structure of the Lactococcus lactis formamidopyrimidine-DNA glycosylase bound to an abasic site analogue-containing DNA.

The formamidopyrimidine-DNA glycosylase (Fpg, MutM) is a bifunctional base excision repair enzyme (DNA glycosylase/AP lyase) that removes a wide range of oxidized purines, such as 8-oxoguanine and imidazole ring-opened purines, from oxidatively damaged DNA. The structure of a non-covalent complex between the Lactoccocus lactis Fpg and a 1,3-propanediol (Pr) abasic site analogue-containing DNA has been solved. Through an asymmetric interaction along the damaged strand and the intercalation of the triad (M75/R109/F111), Fpg pushes out the Pr site from the DNA double helix, recognizing the cytosine opposite the lesion and inducing a 60 degrees bend of the DNA. The specific recognition of this cytosine provides some structural basis for understanding the divergence between Fpg and its structural homologue endo nuclease VIII towards their substrate specificities. In addition, the modelling of the 8-oxoguanine residue allows us to define an enzyme pocket that may accommodate the extrahelical oxidized base.

Amino Acid Sequence↗
PubMed1996

Comparison of cryopreservation of supernumerary pronuclear human oocytes obtained after intracytoplasmic sperm injection (ICSI) and after conventional in-vitro fertilization.

A comparison was made of pronuclear stage human oocytes obtained either after classical in-vitro fertilization (IVF) or after intracytoplasmic sperm injection (ICSI). After ICSI or IVF, three fertilized oocytes from each patient were kept in culture for a further 24 h before embryo transfer. The surplus oocytes were cryopreserved using the 'open freezing system' and 1,2-propanediol and sucrose as cryoprotectants. A cohort of 817 and 1626 oocytes in pronuclear stage were frozen after IVF and ICSI respectively. Of these, 333 and 744 zygotes have been thawed, of which 78 and 76.5% were morphologically intact zygotes after IVF and ICSI respectively. From the 204 (ICSI) and 89 (IVF) zygote transfers performed, 34 (17%) and 18 (20%) pregnancies were established. Both groups showed a similar abortion rate of approximately 20%. It is concluded that pronuclear stage oocytes resulting from ICSI can be successfully frozen/thawed and the survival and pregnancy rates achieved are comparable to those for zygotes obtained after IVF.

Cryopreservation↗
PubMed1997

Birth from cryopreserved embryos following in-vitro maturation of oocytes and intracytoplasmic sperm injection.

This case report describes the birth of a baby following the transfer of cryopreserved embryos generated from intracytoplasmic sperm injection (ICSI) carried out on the second day after oocyte pick-up of in-vitro-matured metaphase I and germinal vesicle stage oocytes. The couple had a history of three failed intrauterine insemination attempts and reduced fertilization rates in two previous in-vitro fertilization (IVF) cycles. In the IVF-ICSI treatment cycle, 6/11 mature oocytes became fertilized following ICSI on the first day. However, the patient failed to conceive following the transfer of three embryos. Five oocytes were immature (two at metaphase I stage and three with a germinal vesicle) and these were cultured overnight. All had extruded a polar body by the following day and ICSI was therefore performed; four oocytes became fertilized, and were cryopreserved at the pronulear stage in propanediol. In the next treatment cycle, transfer of frozen embryos was planned. The pronuclear zygotes were thawed and cultured for 24 h prior to the transfer of two embryos in a cycle stimulated with low doses of follicle stimulating hormone. This resulted in a pregnancy and the delivery of a healthy baby boy. In-vitro maturation of metaphase I and germinal vesicle oocytes which are routinely collected in IVF-ICSI cycles, followed by second day ICSI fertilization, may provide a valuable source of embryos for infertile couples.

Adult↗
PubMed1997

Transfer of cryopreserved-thawed pre-embryos in a cycle using exogenous steroids without prior gonadotrophin-releasing hormone agonist suppression yields favourable pregnancy results.

We have analysed the use of a programmed cycle of administration of exogenous steroids without prior suppression with a gonadotrophin-releasing hormone agonist (GnRHa) for the transfer of cryopreserved-thawed pre-embryos. From July 1992 to June 1994, 199 cycles (162 patients) were studied. Pre-embryos had been previously cryopreserved at the pronuclear stage using 1.5 M 1,2-propanediol as a cryoprotectant. Preparation of the endometrium was achieved in a step-up regime with transdermal oestradiol patches (0.1 to 0.4 mg). Progesterone in oil (50 mg i.m.) was started on cycle day 13. Pre-embryos were thawed on day 14 and transferred on day 15 after evidence of survival and cleavage. The mean (+/- SD) age of patients undergoing transfer was 35.4 +/- 4.3 years. The mean number of pre-embryos thawed was 4.7 +/- 1.8 with a mean of 3.3 +/- 1.4 pre-embryos being transferred. Eight of the cycles demonstrated follicular development >16 mm prior to thaw and transfer; however, these patients did not demonstrate a luteinizing hormone surge. Mean endometrial thickness on day 13 was 10.8 +/- 2.1 mm. Overall pregnancy rate was 29.2% (57/195). The ongoing or delivery rate was 16.1% (32/195). The rate of preclinical losses per transfer was 6.2% (12/195). Overall, the implantation rate was 6.2% (47/757). Thus, the use of a programmed cycle for cryopreserved embryo transfer yields favourable pregnancy outcome and offers practical advantages to patients. Prior suppression with a GnRHa is not necessary for endometrial preparation.

Adult↗