Platelet-activating factor improves intrauterine insemination outcome.

OBJECTIVE: Our purpose was to investigate intrauterine insemination pregnancy rates after human spermatozoa exposure to platelet-activating factor. STUDY DESIGN: Spermatozoa were incubated with platelet-activating factor in sperm-washing medium before intrauterine insemination. Patients whose sperm were incubated with sperm-washing medium alone served as controls. Pregnancy outcome was determined by ultrasonography (fetal heartbeat). RESULTS: Patients whose sperm were treated with exogenous platelet-activating factor had a significantly (P <.05) higher pregnancy rate (40%) than patients (20%) not receiving treatment. CONCLUSION: Inclusion of platelet-activating factor into a semen processing protocol, before intrauterine insemination, will significantly improve pregnancy rates. Platelet-activating factor may have a stimulatory effect on centriole-intact spermatozoa, enhancing their motility and fertilization success and resulting in improved pregnancy rates. Additional studies will elucidate the reproductive significance of platelet-activating factor activity in spermatozoa and its role in the establishment of pregnancy.

Presence of ribonucleic acid in human spermatozoa: differences in content between normal and abnormal spermatozoa.

OBJECTIVE: Our purpose was to determine whether there are any differences in total ribonucleic acid content between normal and abnormal human spermatozoa. STUDY DESIGN: Spermatozoa were obtained from men undergoing routine semen analysis at a university-based reproductive genetics laboratory. Specimens were classified as normal or abnormal according to World Health Organization criteria. Total ribonucleic acid was removed by acid-phenol extraction, and ribonucleic acid expression levels were determined by spectrophotometric analysis. RESULTS: Abnormal spermatozoa were found to have significantly more ribonucleic acid (0.14 +/- 0.02 mg/10(6) spermatozoa) than normal spermatozoa (0.05 +/- 0.01 mg/10(6) spermatozoa; P <.001). CONCLUSION: Ribonucleic acid content is significantly altered in abnormal spermatozoa, and this alteration may be the result of some defect in the posttranscriptional pathway.

Expression of the platelet-activating factor receptor in human spermatozoa: differences in messenger ribonucleic acid content and protein distribution between normal and abnormal spermatozoa.

OBJECTIVE: To determine the expression and distribution of the platelet-activating factor (PAF) receptor in normal and abnormal specimens of human spermatozoa. DESIGN: Prospective analysis of membrane-bound PAF receptors by immunofluorescence and PAF receptor messenger RNA by quantitated reverse transcription-polymerase chain reaction in normal and abnormal spermatozoa. SETTING: University-based reproductive genetics laboratory. PATIENT(S): Men undergoing routine semen analysis. INTERVENTION(S): Normal and abnormal spermatozoa were exposed to rabbit anti-PAF receptor antibody, fluorescein isothiocyanate-conjugated goat anti-rabbit antibody, and fluorescent microscopy or subjected to RNA isolation by acid-phenol extraction and quantitated (MIMIC Construction Kit [Clontech Laboratories, Inc., Palo Alto, CA]) reverse transcription-polymerase chain reaction. MAIN OUTCOME MEASURE(S): Fluorescent intensities at six locations along spermatozoa (end piece, principal tail, midpiece, neck, proximal head, and acrosomal region) and PAF receptor expression (messenger RNA) levels. RESULT(S): Immunofluorescence demonstrated a significant difference in PAF receptor distribution between normal and abnormal human spermatozoa, specifically at the neck region. Additionally, abnormal spermatozoa were found to have statistically significantly more PAF receptor messenger RNA than normal spermatozoa. CONCLUSION(S): Platelet-activating factor receptor expression and distribution are significantly altered in abnormal spermatozoa and this may be the result of some defect in gene transcription.

Extensive and saturable accumulation of paclitaxel by the human platelet.

Little is known about the cellular distribution of paclitaxel in humans. In the present study we examined the distribution of [3H]-paclitaxel in human blood. When 1 microM paclitaxel was incubated with fresh blood at 37 degrees C, the platelet/plasma concentration ratio was 240 +/- 17 (mean +/- SEM), whereas the red blood cell (RBC)/plasma concentration ratio was only 0.59 +/- 0.05. In kinetics experiments using platelet-rich plasma, we observed that the platelet accumulation of paclitaxel was highly temperature- and concentration-dependent. Scatchard analysis of the 37 degrees C uptake data demonstrated a dissociation constant (Kapp) of 0.80 +/- 0.10 microM and a maximal binding capacity of 672 +/- 102 pmol/10(9) platelets. It is proposed that the platelet accumulation of paclitaxel reflects binding to microtubules and may serve as a useful model for binding to less accessible cellular sites.