Biomedical subjects

R J Swanson

Publications and source records attributed to R J Swanson.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Comparison of a discontinuous Percoll gradient method versus a swim-up method: effects on sperm morphology and other semen parameters.

Increasing the proportion of motile and normal spermatozoa is an important objective for assisted reproductive procedures. The aim of this study was to compare the results of a Percoll and swim-up-method, especially on the sperm morphology. The Percoll technique gave a recovery rate of 81.3% of motile spermatozoa against a recovery rate of 28.98% for the swim-up technique. When the percentage of normal spermatozoa was also brought into calculation the recovery rate with the Percoll technique decreased to 62.03% and increased to 31.81% for the swim-up technique. This was due to a decrease in the resultant morphology of the Percoll technique to a median of 8.0% and an increase to 11.5% for the swim-up technique from a median of 10.5% of the original samples.

Centrifugation, Zonal↗

PubMedDate not supplied

Value of sperm morphology assessed by strict criteria for prediction of the outcome of artificial (intrauterine) insemination.

The purpose of this study was to investigate the relationship between sperm parameters and the outcome of artificial (intrauterine) insemination (IUI). One hundred and twenty-six patients undergoing 395 consecutive IUI cycles in a 1-year period in our institution were studied. In all cases, controlled ovarian stimulation and hCG-timed IUI were performed, followed by progesterone supplementation of the luteal phase. In 86 patients, (243 cycles) the husband's sperm was utilized, whereas in 40 couples (152 cycles), donor sperm was used due to severe male factor infertility. Among the sperm parameters of the original ejaculate, % normal morphology (assessed by strict criteria) was the most significant predictor of pregnancy (stepwise regression analysis, P = 0.003). Using logistic regression, morphology was the best predictor of pregnancy (r = 0.12); linearity of movement significantly enhanced the predictive value of morphology alone (r = 0.17, P = 0.004). Overall, the pregnancy rates were significantly higher (P = 0.01) in cases with > or = 14% normal morphology (15% per cycle) compared to cases with < 14% normal morphology (7% per cycle). This threshold level for morphology is in agreement with previously published IVF results. These results underscore the significance of sperm morphology assessed by strict criteria as a predictor of pregnancy outcome in the IUI setting.

Adult↗

PubMedDate not supplied

Enhancement of in vitro murine embryo development by recombinant leukemia inhibitory factor.

OBJECTIVE: Human recombinant leukemia inhibitory factor (rLIF) has been shown to stimulate hatching of murine and ovine embryos in vitro. The temporal and dose-dependent effects of murine rLIF (mrLIF) and human rLIF (hrLIF) on embryo development in two different mouse strains were investigated in this work. METHODS: Two-cell embryos were recovered from the fallopian tubes of superovulated/mated females and cultured in Krebs medium plus bovine serum albumin in microdroplets under oil. RESULTS: In the B6CBF1 strain, mrLIF significantly stimulated blastocyst formation and decreased embryo fragmentation/degeneration when added simultaneously at the initiation of culture or 24 hours thereafter. Human rLIF also had a positive effect on development. In the CD1 strain (lower fecundity), mrLIF dose-dependent effects were observed, with enhanced developmental stimulation achieved with higher doses. CONCLUSIONS: These findings confirm that hrLIF stimulates mouse embryo development in vitro and that different mouse strains show distinct responses to the cytokine. In addition, mrLIF enhances blastocyst formation and decreases embryo fragmentation when added to the embryo culture as early as the two-cell stage.

Animals↗

PubMedDate not supplied

Relationship between morphology and motion characteristics of human spermatozoa in semen and in the swim-up sperm fractions.

In this study, the authors evaluated the morphology pattern and motion characteristics of human spermatozoa before and after swim-up separation. Samples were divided into two, morphologically different groups according to the percentage of normal sperm forms assessed by the strict criteria of the Norfolk laboratory: "good"(G) and "poor" (P) prognosis patterns. The percentages of normal forms, slightly abnormal forms, and severe head defects were significantly different in the two groups. Motile characteristics were analyzed by a computerized semen analyzer with constant parameter settings. Before swim-up there were no significant differences in semen volume, percentage of neck and tail defects, concentration, or percentage of motility and linearity, but the mean velocity was higher in group G. After swim-up the percentage of motility, total number of motile cells, and recovery rate were higher for group G, and the incidence of severe head defects correlated negatively with the percentage of cells with a velocity of greater than 80 microns/sec. The results suggest that patients with a high incidence of sperm head defects have impaired original velocity, and swim-up selects for velocity as well as normal forms and motility. Although motility and velocity improved substantially after swim-up, the recovery rate and percentage of motility were significantly lower in the P group.

Cell Separation↗