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Biomedical subjects

William E Roudebush

Publications and source records attributed to William E Roudebush.

15 recordsLinked to original sources
PubMed2006

Influence of the preimplantation embryo development (Ped) gene on embryonic platelet-activating factor (PAF) levels.

PURPOSE: A major gene responsible for the control of preimplantation cleavage rate is the Ped gene, the product of which is the Qa-2 protein. Fast, but not slow developing mouse embryos express the Qa-2 protein. Platelet-activating factor (PAF) is a novel and potent signaling phospholipid that has unique pleiotropic properties in addition to platelet activation. PAF plays a significant role in virtually every reproductive event, including ovulation, fertilization, implantation, and parturition. The role of the Ped gene in PAF production by preimplantation embryos is yet to be established. The presence of this gene provides embryos with a reproductive advantage over those that are Ped negative, and may also serve as a regulator of PAF synthesis. The study hypothesis is that the amount of PAF produced is dependent upon the presence or absence of the Ped gene. METHODS: B6.K1 (Ped negative) and B6.K2 (Ped positive) mouse embryo-conditioned culture media were assayed for PAF content by a PAF-specific radioimmunoassay. RESULTS: There was a significant (p < 0.001) difference in blastocyst development rates between the Ped+ B6.K2 (61.0%) and the Ped- B6.K1 (25.3%) embryo culture groups. There was a significant difference (p < 0.05) in PAF production between the Ped+ B6.K2 (4.70+/-0.46 pmol per embryo) embryo culture group and the Ped- B6.K1 (10.02+/-3.49 pmol per embryo) embryo group. The B6.K1 (Ped-) embryo group produced >2x more PAF than did the B6.K2 (Ped+) group. CONCLUSIONS: The Ped gene plays a role in PAF production and release in preimplantation stage embryos. The use of two mouse identical strains, except for the Ped gene, show that its presence is associated with an increase in developmental potential. Embryos where the Ped gene was absent produced significantly higher levels of PAF, which may aid in their survival.

Animals↗
PubMed2006

Platelet-activating factor acetylhydrolase activity affects sperm motility and serves as a decapacitation factor.

OBJECTIVE: To determine the relationship between platelet-activating factor acetylhydrolase (PAFah) content in semen and sperm motility. DESIGN: The PAFah levels in semen were measured and correlated with sperm motility. SETTING: Clinical laboratory in a private assistant reproductive technology clinic. PATIENT(S): Three hundred and twelve men seeking diagnosis and treatment of infertility. INTERVENTION(S): Semen samples were collected from 312 healthy mature men seeking infertility treatment. Sperm motility and PAFah activity were measured in seminal plasma. Data was analyzed by Student's t test and regression analysis. MAIN OUTCOME MEASURE(S): PAFah activity and sperm motility. RESULT(S): Seminal PAFah content ranged from a low of 179 IU/L to a high of 2,457 IU/L. The overall mean PAFah content in semen was 780.59 IU/L. Linear regression analysis revealed a significant (R2 = 0.655) and negative relationship between PAFah content in semen and sperm motility. Semen specimens with high percent motility (> or = 50%) had significantly lower PAFah concentrations (442.03 +/- 14.37 IU/L) than those with the lower percent sperm motility (< 50%) (882.16 +/- 18.45 IU/L). CONCLUSION(S): The data confirm the presence of PAFah in human semen and that activity is significantly and negatively correlated with sperm motility. The PAFah is proven to be a candidate for sperm decapacitation factors, whereas PAF is qualified to be a candidate for sperm capacitation factors.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2005

Impact of body mass index values on sperm quantity and quality.

Body mass index (BMI) has been demonstrated to affect female fertility; however, little information is available on the impact of BMI on male fertility or semen parameters. Therefore, the study objective was to determine the relationship between BMI and semen parameters, including sperm chromatin integrity. We analyzed data on semen samples from 520 men who were grouped based upon calculated BMI values (normal, 20-24 kg/m(2); overweight, 25-30 kg/m(2); obese, >30 kg/m(2)). The data collected included patient height and weight, semen volume, sperm concentration, percent sperm motility, percent sperm morphology (normal forms), and sperm chromatin integrity (DNA fragmentation index [DFI]). Data were analyzed by regression analysis and analysis of variance (ANOVA) with Tukey's test for multiple pairwise comparisons. The overall BMI mean (+/-SEM) was 27.5 (+/-0.49) kg/m(2). Linear regression revealed a significant (P < .05) and negative relationship between BMI and the total number of normal-motile sperm cells. ANOVA revealed a significant difference (P < .05) in the total number of normal-motile sperm cells among the different BMI groups. The number of normal-motile sperm cells per BMI group was as follows: normal, 18.6 x 10(6); overweight, 3.6 x 10(6); and obese, (0.7) x 10(6). All multiple pairwise comparisons were found to be significantly (P < .05) different. The overall DFI mean (+/-SEM) was 24.7 (+/-2.57). Linear regression revealed a significant (P < .05) and positive relation between BMI and DFI. Men presenting with a BMI greater than 25 kg/m(2) have fewer chromatin-intact normal-motile sperm cells per ejaculate. Therefore, to ensure maximum fertility potential, patients may be advised to reduce body weight.

Adult↗
PubMed2005

High seminal platelet-activating factor acetylhydrolase activity in men with spinal cord injury.

Spinal cord injury (SCI) causes male infertility, with low sperm motility the major long-term cause. It has been suggested in previous studies that some seminal components may be responsible for the pathological asthenozoospermia. It is hypothesized that platelet-activating factor (PAF) acetylhydrolase (PAFah), which originates in the epididymis and other accessory sexual glands, may be a causative factor. This enzyme catalyzes PAF to acetate and biologically inactive lyso-PAF. PAF is well recognized to be an important phospholipid mediator that stimulates sperm motility and enhances sperm capacitation and fertilization. The present study was designed to analyze differences in PAFah activity in semen of men with SCI and age-matched healthy men. PAFah assay reagent kits were used to measure enzymatic activity by monitoring the production rates of 4-nitrophenol on a spectrophotometer during a given interval. The results showed that subjects with SCI had a higher concentration of PAFah than men in the control group (P < .001). A statistically significant negative correlation was found between enzymatic activity and sperm motility (r(2) = 0.8449; P < .001). Further studies will determine whether seminal vesicle dysfunction in men with SCI leads to abnormal PAFah activity, resulting in low sperm motility.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2005

The significance of platelet-activating factor and fertility in the male primate: a review.

Since its discovery nearly 30 years ago platelet-activating factor (PAF) has emerged as one of the more important lipid mediators known. PAF (1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphorylcholine) exists endogenously as a mixture of molecular species with structural variants of the alkyl moiety. PAF is a novel potent signaling phospholipid that has unique pleiotropic biological properties in addition to platelet activation. PAF also plays a significant role in reproduction and is present in the sperm of a number of primate species. PAF content in squirrel monkey sperm is significantly higher during the breeding season than the non-breeding season. PAF content in rhesus sperm has a significant relationship with sperm motility. PAF content in human sperm has a positive correlation with seminal parameters and pregnancy outcomes. The enzymes (lyso-PAF-acetyltransferase and PAF-acetylhydrolase) necessary for PAF activation and deactivation are present in primate sperm. PAF-acetylhydrolase may act as a "decapacitation factor". Removal of this enzyme during capacitation promotes PAF synthesis increasing primate motility and fertilization. PAF also plays a significant role in the fertilization process, enhancing the fertilization rates of oocytes. Enhanced embryo development has also been reported in oocytes fertilized with PAF-treated sperm. Exogenous PAF will also significantly improve primate artificial insemination pregnancy outcomes. PAF antagonists inhibit sperm motility, acrosome reaction, and fertilization thus suggesting the presence of receptors for PAF. The PAF-receptor is present on primate sperm, with altered transcript levels and distribution patterns on abnormal cells. Whereas, the exact mechanism of PAF in sperm function and reproduction is uncertain, its importance in normal primate fertility is substantial.

Animals↗
PubMed2004

Platelet-activating factor significantly enhances intrauterine insemination pregnancy rates in non-male factor infertility.

OBJECTIVE: To determine the efficacy of treating semen specimens with platelet-activating factor (PAF) before IUI. DESIGN: Prospective randomized double-blinded study of PAF treatment of sperm for patients with a history of infertility undergoing IUI. SETTING: Private infertility center. INTERVENTION(S): Patients had ovulation induction therapy with clomiphene citrate (CC) or gonadotropin, two IUIs per month with PAF treatment. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates. RESULT(S): There was a significant difference in IUI pregnancy rates per cycle between control (10/56; 17.9%) and PAF (14/47; 29.8%) treatment groups in the normal male study arm. There was a significant difference in cumulative IUI pregnancy rates between control (10/35; 28.6%) and PAF (14/26; 53.9%) patient groups in the normal male study arm. There was no significant difference in IUI pregnancy rates per cycle between control (12/124; 9.7%) and PAF (14/119; 11.8%) treatment groups in the male factor study arm. There was no significant difference in cumulative IUI pregnancy rates between control (12/46; 26.1%) and PAF (14/38; 36.8%) patient groups in the male factor study arm. There was a significant difference in overall cumulative IUI pregnancy rates between control (21/81; 25.9%) and PAF (27/64; 42.2%) patient groups. CONCLUSION(S): The inclusion of PAF into the IUI sperm wash procedure significantly improves pregnancy rates. However, the significant improvement can only be shown to affect men presenting with normal semen parameters.

Adult↗
PubMed2004

Exposure of preimplantation embryos to platelet-activating factor increases birth rate.

PROBLEM: Platelet-activating factor (PAF) plays a significant role in fertility. Preimplantation stage embryos produce PAF (ePAF) which is required for development. PAF's mechanism of action is receptor-mediated and its presence has been reported in the developing mouse and human embryo. Exposure of preimplantation stage mouse embryos results in higher implantation rates. However, the effect of such treatment on live-birth rates and birth weights has not been reported. Therefore, the objective the study was to determine the effect of exposing preimplantation mouse embryos to PAF on subsequent birth rate and weight. DESIGN: Two-cell stage preimplantation stage mouse embryos exposed to PAF (10(-7) M) for 15 min prior to intraoviductal transfer. METHODS: Preimplantation stage embryos were recovered from eCG/hCG primed BDF1 female mice. Embryos were exposed to synthetic PAF (10(-7) M) for 15 min. PAF-treated embryos were transferred to the oviducts of pseudopregnant female CD-1 female mice. Superovulated and cultured BDF1 embryos not treated with PAF served as in vitro controls and naturally ovulated embryos with no collection/culture served as in vivo controls. Embryos were permitted to develop to term (18-21 days). The number of pups born per litter and litter weights subsequently were recorded. RESULTS: A total of 160 BDF1 mouse embryos were collected, treated, and transferred (20 per CD-1 recipient) as described. There was a significant (P < 0.05) increase in the number of pups born to the PAF treatment group (56/80; 70%) as compared to the control group (44/80; 55%). There was also a significant difference (P < 0.05) in litter birth weights between the PAF (1.31 g/litter) and controls groups (1.25 g/litter). There was a significant difference (P < 0.05) in birth weights between the PAF treatment group and the in vivo group (1.51 g/litter). There was a significant difference in birth weights between the in vitro-control and in vivo groups (1.51 g/litter). There were no observational malformaties to pups born in any group. CONCLUSIONS: Brief exposure of preimplantation stage embryos to PAF will result in a significant increase of delivery rates (pups/litter) as well as birth weights. However, the increase of birth weight was significantly below that found naturally. Additional studies are warranted to elucidate the mechanism of PAF's action in the preimplantation stage embryo and subsequent uterine development.

Animals↗
PubMed2003

Chromosomal location, structure, and temporal expression of the platelet-activating factor receptor (PAFr) gene in porcine endometrium and embryos relative to estrogen receptor alpha gene expression.

Although platelet-activating factor receptor (PAFr) gene was well characterized in the human, little was known about it in domestic animals. Porcine PAFr gene was mapped using fluorescence in situ hybridization (FISH). The structure of this gene was investigated using a 5' rapid amplification of cDNA ends (RACE) technique. Temporal expression of PAFr and estrogen receptor alpha genes (ER), and distribution of the PAFr transcripts in porcine endometrial and embryonic tissues on days 0, 10, 12, 14, 16, and 18 were analyzed using DNA competitors and reverse transcription and polymerase chain reaction (RT-PCR). The porcine PAFr gene was mapped to SSC6q26-27. Alternative splicing of primary transcripts of the PAFr gene produced two different transcripts. Transcript 1 was expressed in all tissues and cells, and transcript 2 was detected in all tissues but white blood cells. The temporal expression of the PAFr gene in endometrial (P > 0.05) and embryonic (P < 0.05) tissues of pregnant sows increased from day 10 to 16. The temporal expression of ER genes in endometrial tissues of pregnant sows decreased from day 10 to 18 (P < 0.05). In addition, ER expression was detectable in 20-60% of embryonic tissue samples, which generally decreased. In combination with previously obtained data on PAF and estradiol-17beta (E(2)) concentrations in pregnant uterine luminal fluids (pULF), endometrial and embryonic tissues, the present results indicated that the increasing PAFr transcripts were positively associated with increasing levels of PAF. Both ER transcripts and E(2) found in pULF decreased correspondingly from day 13 to 16. These results indicate that via PAFr, PAF could play a dominant role in peri-implantation development in pigs as compared to E(2).

Animals↗
PubMed2003

Fertilization potential of human sperm is correlated with endogenous platelet-activating factor content.

PURPOSE: Platelet-activating factor (PAF) is a potent signaling phospholipid that is found in mammalian sperm and has a positive correlation with fertility. Whereas PAF is present in human sperm, there are no relational reports on its content and the cells fertilization potential. Therefore, the study objective was to determine if PAF content in capacitated-induced sperm is related to fertilization potential as determined by the sperm penetration assay (SPA). METHODS: Endogenous sperm lipids were measured for PAF content by a specific radioimmunoassay following insemination of zona pellucida-free hamster ova. Data were analyzed by regression analysis and Student's t test. RESULTS: Regression analysis revealed a positive and significant relation (R2 = 0.806; P < 0.05) between PAF content in human sperm and SPA outcome (pass: > or = 5.0; fail: < 5.0, penetrations/ova). Patients that passed (22.61 +/- 5.21 picomoles/10(6)) the SPA had significantly (P < 0.01) higher PAF levels in their sperm than patients that failed (12.91 +/- 1.76 picomoles/10(6) cells) the test. CONCLUSIONS: PAF content in capacitated-induced sperm has a significant and positive relationship with fertilization potential. Fertilization potential may be predicted by measuring PAF levels in capacitation-induced human sperm. Determining PAF content in capacitated human sperm may be a beneficial diagnostic tool for the infertility specialist.

Biomarkers↗
PubMed2003

Organization of porcine platelet-activating factor receptor gene.

Four exons of porcine platelet-activating factor receptor (PAFr) gene expressing transcript 1 and transcript 2 were determined previously. In this study, we cloned and sequenced a new exon, which also initiates transcript 2, and determined the order of 5 exons in the PAFr gene. In addition, two other variants of transcript 2 were found, but no additional variants of transcript 1 were found. Transcript 2 has three variants that were detected in porcine tissues other than in white blood cells.

Animals↗
PubMed2002

The pig platelet-activating factor receptor gene is expressed at the mRNA level in different tissues and is mapped to chromosome 6.

After the pig platelet-activating factor receptor (PAFr) gene was cloned and sequenced, the chromosomal location of this gene was studied using a pig/rodent somatic cell hybrid panel containing 27 cell lines. The results indicated that the pig PAFr gene is located on SSC6q22-23. Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is thought to be very important in the animal reproductive processes. Its function is mediated through a membrane-bound receptor. Pig PAFr mRNA distribution in different tissues was tested using reverse transcription and PCR (RT-PCR) reactions. All tissues examined expressed PAFr. Using a pig PAFr gene DNA competitor, PAFr expression was quantificated. The pig PAFr mRNA expression level was estimated to be from 1 x 10(2) to 1.2 x 10(4) copies of complementary DNA (cDNA) per 50 ng of total RNA. The highest level was found in lung, and the lowest in the skeletal muscle. These results demonstrated that PAFr was differentially expressed in pig tissues.

Animals↗
PubMed2002

Relationship between platelet-activating factor concentration in rhesus monkey (Macaca mulatta) spermatozoa and sperm motility.

Platelet-activating factor (PAF) is a potent signaling phospholipid that has been implicated in a number of biological activities. PAF concentration in primate spermatozoa has a positive correlation with fertility. While PAF is present in rhesus spermatozoa, there are no relational reports on its concentration and the cell's motility. The study objective was to determine if PAF concentration in rhesus spermatozoa was correlated with motility indices (percent motility and forward progression). Semen was collected from sexually mature males and cell counts, and percent motilities and forward progressions were recorded prior to PAF measurement by radioimmunoassay. Spermatozoa-derived PAF concentration ranged from a low of 0.9 picomoles/10(6) cells to a high of 13.0 picomoles/10(6) cells. The overall mean (+/-SEM) PAF concentration was 4.6 (+/-1.6) picomoles/10(6) spermatozoa. Regression analysis revealed a positive and significant relationship between PAF concentration in the spermatozoa and percent motility (R2 = 0.914; P < 0.01) as well as forward progression (R2 = 0.849; P < 0.05). A receiver-operator characteristic curve and the calculation of the probability that a positive forward progression will be predicted indicated a cutoff limit of 1.5 picomoles/10(6) cells for PAF concentration in rhesus sperm. Rhesus monkey spermatozoa motility was significantly greater (P < 0.01) in the high-PAF (> or =2 picomoles/10(6) cells) group (31.0 +/- 7.6) than in the low-PAF (<2 picomoles/10(6) cells) group (6.8 +/- 2.1). Rhesus monkey spermatozoa forward progression was significantly greater (P < 0.05) in the high-PAF (> or =2 picomoles/10(6) cells) group (3.0 +/- 1.0) than in the low-PAF (<2 picomoles/10(6) cells) group (0.7 +/- 0.3). The data demonstrate that PAF concentration in rhesus spermatozoa has a significant relationship with percent motility and the cell's forward progression. Determining PAF concentration in spermatozoa may be a significant predictor of fertility in the primate. Additional studies will elucidate the role of PAF in spermatozoa function and the significance PAF plays in primate fertility.

Animals↗
PubMed2002

Embryonic platelet-activating factor: temporal expression of the ligand and receptor.

PURPOSE: Preimplantation embryos synthesize platelet-activating factor (PAF) and this embryo-derived PAF is required for development. PAF's signal transduction is receptor-mediated and PAF-receptor mRNA is present in early embryos. The study objective was to determine the relationship between PAF production and PAF-receptor mRNA expression levels in mouse preimplantation embryos. METHODS: Embryo-derived PAF levels were determined by radioimmunoassay. Embryonic PAF-receptor mRNA levels were determined by semiquantitated reverse transcription-polymerase chain reaction. RESULTS: Embryonic-PAF increased as time progressed at a relatively constant rate (1.4-1.9 x) except between the eight- and morula-cell stages where levels increased sevenfold. Embryonic PAF-receptor expression was highest at the two-cell stage and decreased steadily until the morula stage before increasing again. Regression analysis of embryo-derived PAF on PAF-receptor expression does not demonstrate a significant relationship. CONCLUSIONS: PAF-receptor expression (mRNA) levels decrease, while embryo-derived PAF levels decrease, as the preimplantation embryo develops. Embryonic-PAF and PAF-receptor mRNA expression do not appear related. Therefore, embryonic-PAF does not appear to regulate expression of its own receptor in vitro. The data provide a clue to the complicated cell signaling system involving PAF production and receptor expression that may help our understanding of developmental events.

Animals↗