Biomedical subjects
J Leeton
Publications and source records attributed to J Leeton.
Environment of the preimplantation human embryo in vivo: metabolite analysis of oviduct and uterine fluids and metabolism of cumulus cells.
OBJECTIVE: To determine the levels of metabolites surrounding the human oocyte and embryo in vivo. DESIGN: Oviduct and uterine fluids were collected throughout the menstrual cycle. Cumulus cells were collected at oocyte retrieval and their production of metabolites was assessed. Samples were analyzed for pyruvate, lactate, and glucose by microfluorimetry. PATIENTS: Luminal fluids were collected from naturally cycling patients at the time of routine clinical investigation. Patient consent and hospital ethics approval were obtained for this study. RESULTS: Pyruvate in the oviduct did not vary with the day of cycle, the mean value was 0.24 mM. Lactate and glucose concentrations varied with the day of cycle; lactate increasing from 4.87 mM in the follicular phase to 10.50 mM at the time of ovulation, whereas glucose decreased from 3.11 mM in the follicular phase to 0.50 mM midcycle and subsequently increased to 2.32 mM in the luteal phase. The concentrations of pyruvate, lactate, and glucose in uterine fluid remained constant throughout the cycle (0.10, 5.87, and 3.15 mM, respectively). All metabolite concentrations in uterine fluid were significantly different from those in the oviduct midcycle. Cumulus cells readily consumed glucose in vitro, with lactate being the major metabolite produced. CONCLUSION: These data indicate that lactate and glucose concentrations in the oviduct change with day of cycle and that the human embryo is exposed to different metabolite concentrations as it passes along the tract. Furthermore, cumulus cells readily consume glucose, producing lactate. Therefore, the early human embryo is exposed to low glucose and high lactate levels in vivo.
Uterine glandular area during the menstrual cycle and the effects of different in-vitro fertilization related hormonal treatments.
The human uterine glandular epithelium undergoes a sequence of well characterized changes during the menstrual cycle that presumably play an important role in preparation for blastocyst implantation. The aim of this study was to measure objectively glandular volume over the entire menstrual cycle and compare the results with eight different clinical superovulation or hormone replacement therapy (HRT) subject groups. Endometrial biopsies were taken from control normal menstrual cycle subjects (n = 96), and eight other smaller groups of women who had received different in-vitro fertilization (IVF) related treatments. The total area of glandular epithelium was objectively measured from routine histological slides using computerized image analysis. Control menstrual cycle results showed a significantly greater gland area in the early secretory stage of the cycle than at any time between the early proliferative through to the mid-late proliferative stages (P < 0.05). IVF patients receiving clomiphene citrate and human menopausal gonadotrophin had a significantly smaller glandular area than those in the control groups at equivalent stages of the menstrual cycle. The use of progesterone supplementation removed this significant difference. Patients on the ¿Flare' regime had the highest gland area, although this was not significantly different from controls. Buserelin down-regulation gave a gland area that was closest to the normal cycle controls. The three HRT groups showed high variability in gland volume between patients. The results from this study demonstrate that superovulation can cause significant alterations in endometrial gland volume, but that these do not necessarily preclude implantation.
The changing pattern of egg donation.
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Preparation of the endometrium for egg donation.
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Patient selection for assisted reproduction.
Patient selection is a critical factor in influencing results in assisted reproduction. Patients should be assessed individually in terms of all relevant fertility factors including age, duration and aetiology of infertility and psycho-social attitudes so that an approximate prognosis of their management can be made. Restrictive criteria for patient selection will enhance a programme's results but at the expense of depriving some couples of their only chance of conception. The best overall management of each individual infertile couple should always remain the main criteria for selection into a particular assisted reproduction programme.
Turner's syndrome patients lack tight junctions between uterine epithelial cells.
Eleven endometrial biopsies, taken from six Turner's syndrome patients receiving hormone replacement therapy prior to treatment by oocyte donation and embryo transfer, were assessed by freeze fracture followed by electron microscopy for epithelial tight junctions. Nine of the eleven biopsies had no discernible tight junctions; the other two biopsies had reduced and disorganized junctional structures. Two patients subsequently became pregnant following embryo transfer. It is concluded that compromised epithelial integrity does not prevent embryo implantation in the human, an observation that is consistent with a barrier role for the epithelium except at times when appropriately conditioned with oestrogen and progesterone to induce receptivity for implantation.
Tight junctions of human uterine epithelial cells change during the menstrual cycle: a morphometric study.
Tight junctions between luminal epithelial cells of the human uterus were studied by freeze-fracture electron microscopy. It was found that junctional complexity decreased during the menstrual cycle, and we explore how this finding may contribute to the role of the uterus in facilitating implantation.
Ultrasound-guided embryo transfer: a controlled trial.
Embryo transfer (ET) was performed in 94 patients using transvaginal ultrasound guidance. Pregnancy rates were increased over a control group of 246 patients, although statistical significance was reached only in the subgroup of single ETs. Advantages over the traditional blind technique of ET were observed. Acceptance of the procedure by both clinicians and patients was high.
A comparison of pregnancy rates for 131 donor oocyte transfers using either a sequential or fixed regime of steroid replacement therapy.
This study describes the overall results of 131 donor oocyte transfers between 1982 and 1989 when 30 pregnancies resulted (23% pregnancy rate/transfer). A retrospective comparison of results between an earlier sequential hormone replacement regime and a more recent low dosage, variable length oestrogen replacement shows that the latter offers greater flexibility and a promising trend towards higher pregnancy rates.
Successful pregnancy using known donor oocytes fertilized in vitro by spermatozoa obtained by electro-ejaculation from a quadriplegic husband.
A 34-year-old quadriplegic man with a C6/C7 spinal cord lesion of 10 years' duration fathered a child with his 35-year-old wife who had undergone a premature menopause 10 years earlier. Pregnancy was achieved from in-vitro fertilization of two oocytes donated by the wife's sister using spermatozoa from the husband obtained by repeated electro-ejaculation techniques. A healthy male infant weighing 2250 g was delivered by Caesarean section at 37 weeks following mild pre-eclampsia.
The current status of IVF surrogacy in Australia.
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Pregnancy results following embryo transfer in women receiving low-dosage variable-length estrogen replacement therapy for premature ovarian failure.
This study was undertaken to evaluate the effectiveness of a new, constant low-dose, variable-length estrogen replacement therapy in preparing the endometrium of women suffering premature ovarian failure for embryo implantation. Five of 10 patients receiving the new regime became pregnant following a total of 14 embryo transfers. This study proves the efficacy of low-dosage variable-length estrogen replacement therapy for preparing the endometrium for embryo implantation in patients suffering premature ovarian failure. These studies confirm earlier observations that sequentially increasing doses of estrogen during the follicular phase are unnecessary for implantation and that the length of the follicular phase within certain undefined limits is not critical. A second important observation arising from this study concerns the relative effectiveness of the route of administration of progesterone. Five of seven patients became pregnant after receiving vaginal pessaries, compared to none of seven following intramuscular injections.
Uterine receptivity in women receiving steroid replacement therapy for premature ovarian failure: ultrastructural and endocrinological parameters.
Endometrial biopsies and plasma oestradiol (E2) and progesterone (P4) levels in 23 patients were evaluated during 26 replacement therapy cycles for premature ovarian failure. Plasma E2 and P4 levels showed wide patient to patient variability, despite each patient being given the same hormone replacement therapy. Biopsies were studied by conventional histological dating and scanning electron microscopy (SEM). Eight morphological features of the surface epithelium that have previously been linked to uterine receptivity for implantation were identified and quantified. No correlation was found between endometrial surface morphology by SEM and circulating E2 and P4 levels. The results of this study do not support the hypothesis that there is an obligatory link between any of the eight morphological features measured in this study and uterine receptivity for implantation. To date, three ongoing pregnancies have been achieved following 18 embryo transfers to a total of 10 of the women in the study group.
Ultrastructural study of human uterine epithelium from a patient with a confirmed pregnancy.
Scanning and transmission electron microscopy have been used to study the uterine epithelial cells from a pregnant human uterus approximately 8 days after ovulation. The ultrastructural appearance of the epithelial cells generally conforms with that previously described as showing receptivity, although some significant regional variability exists.
The legal dilemma of in-vitro fertilization surrogate pregnancy in Victoria.
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Management of unruptured tubal pregnancy by aspiration of sac under ultrasound control.
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A case of female infertility investigated by contrast-enhanced echo-gynecography.
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