Biomedical subjects
Alison Taylor
Publications and source records attributed to Alison Taylor.
ABC of subfertility. Making a diagnosis.
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ABC of subfertility: extent of the problem.
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Selective regulation of xSlo splice variants during Xenopus embryogenesis.
Calcium-activated potassium channels regulate excitability of the adult nervous system. In contrast, little is known about the contribution of calcium-activated potassium channels to excitability of the embryonic nervous system when electrical membrane properties and intracellular calcium levels show dramatic changes. Embryonic Xenopus spinal neurons exhibit a well-characterized developmental program of excitability that involves several different currents including calcium-activated ones. Here, we show that a molecular determinant of calcium-activated potassium channels, xSlo, is expressed during Xenopus embryogenesis even prior to differentiation of excitable tissues. Five different xSlo variants are expressed in embryonic tissues as a consequence of alternative exon usage at a single splice site. One of these variants, xSlo59, is neural-specific, and its expression is limited to late stages of neuronal differentiation. However, expression of the four other variants occurs in both muscle and neurons at all stages of development examined. Electrophysiological analysis of recombinant xSlo channels reveals that the xSlo59 exon serves as a gain-of-function module and allows physiologically relevant levels of membrane potential and intracellular calcium to activate effectively the resultant channel. These results suggest that xSlo59 channels play a unique role in sculpting the excitable membrane properties of Xenopus spinal neurons.
Effect of blastomere loss on the outcome of frozen embryo replacement cycles.
OBJECTIVE: To assess the impact of survival of cryopreservation and thawing with all blastomeres intact on the outcome of frozen embryo replacement (FER) cycles. DESIGN: Prospective observational study. SETTING: University-affiliated tertiary referral assisted conception unit. PATIENT(S): The number of intact blastomeres before cryopreservation and after thawing was prospectively recorded in 1,687 cleavage-stage embryos thawed in 377 FER cycles. The cycles were categorized into two groups: group A (n = 184) included cycles in which all embryos transferred survived the cryopreservation and thawing process with all their original blastomeres intact; group B (n = 193) included cycles in which embryos transferred included at least one partially damaged embryo that has lost up to 50% of its original blastomere number. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Pregnancy and embryo implantation rates. RESULT(S): Groups A and B were comparable with respect to mean age at cryopreservation, mean number of oocytes retrieved and fertilized normally in the fresh cycle, and mean age at frozen transfer. No significant difference was found between the two groups with regard to mean number of frozen and thawed embryos per cycle and mean endometrial thickness reached before P supplementation. More embryos were transferred per cycle in group B than group A (2.4 +/- 0.6 vs. 2.1 +/- 0.6, respectively). However, the pregnancy and clinical pregnancy rates per cycle were significantly higher in group A than in group B (39.1% and 28.3% vs. 22.8% and 13.5%, respectively). The implantation rate was also higher in group A than in group B (17.3% vs. 8.1%, respectively). CONCLUSION(S): FER cycles in which all embryos transferred remained fully intact at thawing achieve a better outcome than those with at least one partially damaged embryo.
Daughters and mothers exercising together: effects of home- and community-based programs.
PURPOSE: This pilot study compares the effectiveness of home- and community-based physical activity interventions that target mothers and daughters to increase physical activity and improve health-related fitness. METHODS: Mothers (45.18 +/- 7.49 yr) and daughters (15.41 +/- 1.33 yr) were randomly assigned to a community-based (CB) (N = 20 participants) or home-based (HB) (N = 14 participants) program. CB participants attended three instructor-led sessions per week for 12 wk. HB participants were asked to participate in 3 sessions per week for 12 wk in a program similar to the CB program. The main difference between the programs was that CB activities were completed at a fitness facility within a university and HB activities were completed in or near the home. Before and after the intervention, changes in health-related fitness and physical activity were assessed. A series of 2 (group assignment) x 2 (time) ANOVAs were conducted to assess changes separately for mothers and daughters. RESULTS: CB participants attended 77% of the sessions, and none of the pairs dropped out. HB participants completed 70% of the recommended sessions, and three pairs dropped out. Mothers and daughters in both groups significantly increased their participation in aerobic, muscular strength, and flexibility activities (P = 0.02 to 0.000). Daughters in both groups significantly improved their muscular endurance (sit-ups,P = 0.000). Mothers in both groups improved their muscular strength (push-ups, P = 0.003), muscular endurance (sit-ups, P = 0.000), flexibility (sit-and-reach, P = 0.008), and aerobic capacity (1-mile walk, P = 0.002). Positive changes in diastolic blood pressure also occurred (P = 0.008). CONCLUSION: Mothers and daughters responded positively to CB and HB physical activity programs. Home-based physical activity programming is a cost-effective means to increase physical activity and improve health-related fitness in these groups.
Young age does not protect against the adverse effects of reduced ovarian reserve--an eight year study.
BACKGROUND: Ovarian reserve significantly influences IVF outcome. Low response to ovarian stimulation due to reduction of ovarian reserve is occasionally encountered in young women. The aim of this study was to evaluate the outcome of IVF treatment in young patients with reduced ovarian reserve. METHODS AND RESULTS: Between January 1993-2001, 762 consecutive patients satisfied the definition of reduced ovarian reserve (raised early follicular phase FSH or gonadotrophin stimulation cycles where three or fewer oocytes were retrieved after routine FSH stimulation) and were included in the study. They were classified into three age groups: young (< or = 30 years), intermediate (31-38 years) and older (>38 years). The three age groups were similar with respect to basal (day 3) serum FSH and estradiol concentrations, cause of infertility and number of previous treatment cycles. Implantation (13, 9.6 and 9.8%), clinical pregnancy (11.8, 10.2 and 10%) and live birth (7.4, 7.3 and 6.8%) rates were not significantly different in the three age groups respectively (P > 0.05). CONCLUSION: This study shows that younger patients with reduced ovarian reserve have a poor outcome of IVF treatment similar to their older counterparts. Such information may be helpful in counselling these patients who otherwise might anticipate an outcome related to their chronological age.