PubMed Health⌕ Search

Biomedical subjects

C Kirby

Publications and source records attributed to C Kirby.

At least 37 records · Page 2Linked to original sources
PubMed1987

Incidence of chromosome anomalies in first-cleavage mouse embryos obtained from frozen-thawed oocytes fertilized in vitro.

To assess the effect of low temperature storage on mouse oocytes we (1) examined the capacity for normal development of embryos derived from frozen oocytes fertilized in vitro after transfer to pseudopregnant foster mothers and (2) analyzed the chromosome complement at the first cleavage division. Fewer frozen than control oocytes were fertilized (36% vs 66%), but after embryo transfer the proportion of fertilized eggs that implanted (67-68%) and formed normal foetuses (50-53%) was similar in the two groups. Freezing did not affect the observed incidence of aneuploidy (1.5-3.3%). The frequency of polyploid embryos derived from frozen oocytes was almost double that of controls (15.8% vs 8.5%), but it is unclear whether this is a real effect of freezing or is an artifact produced by the chromosome preparation technique.

Aneuploidy↗
PubMed1987

Effect of growth factors in culture medium on the rate of mouse embryo development and viability in vitro.

The development of mouse embryos from two cells to blastocysts in Whittingham's T6 medium containing the growth factor insulin or the serum replacement Nu-Serum was studied and compared with development in vivo. The rate of embryo development to blastocysts was increased by the addition of Nu-Serum to T6 and there was a significant increase in the implantation rate of embryos grown in T6 + Nu-Serum compared with T6 alone or with insulin. However, the rate of embryo development in vitro was retarded compared with that in vivo and the number of normal fetuses following transfer to recipients of blastocysts grown in T6 + Nu-Serum was not different from the number for those grown in T6 alone or with insulin. The addition of neither insulin nor Nu-Serum to T6 optimizes embryo development or viability.

Animals↗
PubMed1987

Ultrarapid freezing: a new low-cost and effective method of embryo cryopreservation.

The authors describe a rapid freezing method (ultrarapid freezing) that has been developed for cryopreservation of early cleavage stage embryos. In the present experiments, 2-cell mouse embryos were frozen under a wide range of conditions in an attempt to optimize their survival and viability in vitro and in vivo. The experiments show that embryos exposed briefly (2 to 2.5 minutes) to relatively high concentrations of dimethyl sulfoxide (3 to 4 M) and 0.25 M sucrose survive and develop when plunged directly into liquid nitrogen and thawed in a 37 degrees C waterbath when sealed in 0.25-ml plastic pailettes. Survival and viability rates of ultrarapidly frozen embryos after thawing were comparable to those obtained with conventional slow-freezing techniques. The authors believe that this freezing technique can be further improved and that the speed, ease, and low cost of the method make it a very attractive alternative to more conventional methods for freezing early cleavage stage embryos.

Animals↗
PubMed1987

Tracking of mouse cell lineage using microinjected DNA sequences: analyses using genomic Southern blotting and tissue-section in situ hybridizations.

We examined the feasibility of applying DNA microinjection to label cells for lineage studies of mouse embryos. Tissues from three transgenic mice mosaic due to the insertion of an exogenously introduced mouse beta-major globin gene were analyzed by genomic Southern-blotting and in situ hybridization. These studies allowed the direct quantification and localization of lineage descendants derived from the marked or transformed founder cells. The results of these studies suggested an early segregation of cells in the somatic vs. germ-cell lineages. The in situ hybridization data further demonstrated that cells of the transformed lineages were usually finely dispersed, indicative of extensive cell-cell mixing during mouse development. However, a notable exception to this was the patchy distribution of cells in the kidney (corresponding to individual nephrons), the clustering of transformed cells in individual villi of the small intestine, and the segregation of positive and negative seminiferous tubules in the testis. These data suggest a clonal basis for the organization of development in organs like the kidney, intestine, and testis.

Animals↗
PubMed1987

Development of mouse embryos cryopreserved by vitrification.

Eight-cell mouse embryos were cryopreserved by vitrification in a concentrated solution of dimethylsulphoxide, acetamide, propylene glycol and polyethylene glycol. This solution (designated VS1) does not crystallize when cooled to subzero temperatures but instead forms a glassy transparent solid. Embryos were exposed in three steps to a stock VS1 solution or a saline solution containing 90% of the cryoprotectants in the stock VS1 (90% VS1) and then the suspensions were vitrified by rapid cooling in liquid nitrogen. Of 568 embryos vitrified in 90% VS1, 80% developed in vitro and 98 normal fetuses or young (17% of the total) were produced after transfer to pseudopregnant recipients. By contrast, 22% of 153 embryos vitrified in the stock VS1 developed in vitro, but only one normal fetus was obtained after transfer. These results demonstrate that normal fetuses and young can be produced from embryos cryopreserved by the simple and rapid method of vitrification.

Animals↗
PubMed1986

Cryopreservation of human embryos: progress on the clinical use of the technique in human in vitro fertilization.

Embryo cryopreservation has been studied at Monash University since 1981 and has been available to patients since mid-1983. Of approximately 1200 patients' cycles of in vitro fertilization (IVF), 445 have had excess embryos which they requested to be frozen. To date 205 patients have requested thawing of their embryos and 144 have had frozen-thawed embryos replaced in utero, resulting in 16 pregnancies. Four of these pregnancies aborted, four are ongoing, and eight deliveries have resulted, including one stillbirth at 26 weeks and one set of twins. Analysis of the data collected to date shows that patients with three or more embryos frozen have a significantly higher pregnancy rate than patients with one or two embryos frozen (23 versus 4%, respectively). Embryo viability, but not embryo survival, following freeze-thawing is related to the degree of embryonic fragmentation and the cell stage at freezing. Eight-cell embryos had a significantly higher viability than other cleavage stages. Those resulting in pregnancy tended to be the faster-dividing eight-cell embryos and were undamaged after freezing and thawing. However, when considering all cleavage stages, there was little effect of freezing damage on embryo viability, providing that at least 50% of the cell complement of embryos were intact and the zona pellucida was undamaged. Nor was there any marked effect of the age of embryos postinsemination. It is also possible that patients who were pregnant following the initial embryo replacement on the cycle of IVF treatment are more likely to conceive following replacement of their frozen-thawed embryos.

Cell Count↗
PubMed1986

Mouse interferon produced in vivo does not inhibit the development of preimplantation mouse embryos.

Mouse embryos were cultured in vitro in medium with serum containing interferon which had been induced in vivo by intravenous administration of polyinosine-polycytidylic acid. Two-cell and blastocyst-stage embryos were incubated for 72 and 24 h respectively before embryo transfer, or fixation to determine cell number. Further, blastocysts were outgrown on coverslips in embryo culture medium with fetal calf serum and interferon. Expression of an intermediate filament protein (Mr 55 000) in blastocyst outgrowths was examined with a monoclonal antibody. Embryos appeared morphologically normal and after treatment the mean cell number did not differ from that of controls. Implantation was unaffected by any of the treatments, but culture before transfer in medium containing mouse serum reduced the number of normal fetuses recovered on Day 14 of gestation compared to those cultured in medium without serum. Exposure to interferon did not modify the expression of filaments in the outgrown blastocyst. It is therefore unlikely that interferon induced by viral infection during pregnancy is responsible for preimplantation embryonic loss.

Animals↗
PubMed1985

The effect of porcine relaxin vaginally applied at human embryo transfer in an in vitro fertilization programme.

It has been suggested that the polypeptide hormone relaxin is an early pregnancy factor which facilitates implantation and pregnancy maintenance. To test this hypothesis a double blind randomized placebo controlled trial was conducted where 2 mg purified porcine relaxin or distilled water was given in a vaginal gel on the day of embryo transfer and again 3 days later in a human in vitro fertilization (IVF) programme. There were 96 patients in the randomized trial and 73 patients who were treated concurrently in the same IVF programme acted as a further control group. Of the 51 patients who received relaxin, 10 pregnancies were confirmed and 8 continued successfully. In the 45 patients treated with placebo 10 pregnancies were also confirmed and 6 continued successfully. Amongst the 73 patients concurrently treated outside the trial 14 achieved a pregnancy and 10 continued to term. Thus, porcine relaxin given in these circumstances in a human IVF programme did not appear to improve or interfere with the pregnancy rate. Possible factors that affected the implantation rates in this trial are discussed.

Animals↗
PubMed1985

Culture factors affecting the success rate of in vitro fertilization and embryo transfer.

The development of one-cell mouse zygotes to the blastocyst stage in vitro has been used as a quality control for the media and handling procedures employed for human in vitro fertilization and embryo transfer (IVF/ET). One-cell mouse zygotes were placed in culture in medium containing bovine serum albumin. Aliquots of the same batch of medium containing female patients' homologous serum were used for the fertilization and culture of human oocytes. The following procedures were associated with high rates of mouse embryo development and human pregnancies following IVF/ET: adequate gassing and equilibration of the medium, double-rinsing of pipets and catheters used to handle embryos, use of a HEPES-buffered medium for manipulating embryos in the absence of an atmosphere containing 5% CO2, control of excessive temperature in the vicinity of the embryos, and ET using medium containing 50% patient's serum. The institution of these procedures gave more consistent pregnancy rates. However, there was no obvious association between fertilization and cleavage of human oocytes and the quality of the medium ascertained by the mouse embryo development test. In a continuing trial, we are comparing two culture media (modified Tyrode's and a medium formulated on the composition of human fallopian tube fluid [HTF]) and two culture techniques (culture in medium under oil in petri dishes and in loosely capped tubes). Significantly more mouse zygotes developed in HTF medium compared to Tyrode's medium. In a randomized 2 X 2 factorial trial with human IVF/ET, the highest pregnancy rate occurred when fertilization and culture were carried out in HTF medium under oil, but numbers are not yet sufficient to show any statistical difference between treatments.

Animals↗
PubMed1985

Pathogenicity of mouse hepatitis virus for preimplantation mouse embryos.

Mouse embryos which were hatched from the zona pellucida in vitro in the presence of mouse hepatitis virus (MHV) or outgrown on coverslips and then exposed to MHV were shown by immunohistochemical staining to have virally infected trophoblast cells. Zona-intact embryos incubated with MHV for 48 h (2-cell embryos) or 1.5 h (blastocysts) were resistant to infection. Morulae and early blastocysts collected from donor mice experimentally infected with MHV were not infected, but the medium in which they were flushed from the uterine horns was contaminated with virus. No virus was detected after embryos were washed through three changes of uncontaminated medium. MHV was transmitted to foster mothers when embryos were transferred in medium contaminated with the virus. Fetal and decidual tissues were not infected. We suggest that embryo transfer is an effective and simple alternative to Caesarian rederivation of MHV-contaminated mice.

Animals↗
PubMed1984

Improved conception rate after intrauterine insemination of washed spermatozoa from men with poor quality semen.

The efficacy of high intrauterine insemination of a washed motile fraction of spermatozoa from men with poor quality semen on the day after the luteinising hormone (LH) surge was compared with that of natural intercourse based on symptothermal methods and a single act of intercourse timed on the day after the LH surge in the same 35 couples in a controlled and randomised trial of the three types of cycle. Each couple had been trying to conceive for at least 3 years, the woman being potentially fertile and the only detectable defect related to poor semen quality. After 39 intrauterine insemination cycles, 8 women conceived (all in their first insemination cycle); this procedure was significantly more successful than LH-timed intercourse (0/38; p less than 0.05) and natural intercourse timed by symptothermal methods (1/34; p = 0.022). The technique of intrauterine AIH, with a 'Tomcat' catheter, was simple, painless, and uncomplicated.

Clinical Trials as Topic↗
PubMed1984

In vitro fertilization and embryo transfer program, Department of Obstetrics and Gynecology, University of Adelaide at the Queen Elizabeth Hospital, Woodville, South Australia.

A review is presented summarizing the in vitro fertilization experience at the University of Adelaide, Australia. Initial attempts utilizing the normal cycle were unsuccessful in obtaining a pregnancy. Since 1982 the overall ongoing pregnancy rate has been 21% per embryo transfer, 16% per laparoscopy, and 12% per treatment cycle. A detailed description of presently utilized methodology is presented.

Adult↗
PubMed1984

Culture factors in relation to the success of human in vitro fertilization and embryo transfer.

The development of 1-cell mouse zygotes to the blastocyst stage in vitro has been used as a quality control for the media employed for human in vitro fertilization and embryo transfer (IVF-ET). The following procedures were associated with high rates of mouse embryo development and human pregnancies following IVF-ET: adequate gassing and equilibration of the medium, double rinsing of pipettes and catheters used to handle embryos, use of a HEPES-buffered medium for manipulating embryos in the absence of an atmosphere containing 5% CO2, control of excessive temperature in the vicinity of the embryos, and ET using medium containing 50% patient's serum. The institution of these procedures gave more consistent pregnancy rates. However, there was no obvious association between fertilization and cleavage of human oocytes and the quality of the medium ascertained by the mouse embryo development test.

Animals↗
PubMed1984

Endocrinology of ovarian stimulation for in vitro fertilization.

Understanding of the endocrinology of in vitro fertilization has advanced rapidly in the past 5 years. Despite a multitude of ovarian stimulation regimens a particular regimen has not demonstrated a marked superiority. In principle the achievement of high FSH levels during the early follicular phase to recruit a maximum number of follicles with a tolerable degree of asynchrony for final maturation is confined to a limited time span or 'FSH window' of about 3 to 4 days before negative E2 feedback induces below-threshold FSH levels, thereby condemning all subsequent follicles in that cycle to atresia. It appears that one can widen and/or amplify the 'FSH window' too far from gross hyperstimulation resulting in the recruitment of many follicles with an intolerable degree of asynchrony. This may lead to a defective endocrine environment for the oocytes contained within these follicles or an abnormal luteal environment and an increased frequency of fertilization, cleavage and implantation failure. Whichever regimen is used, the stimulation should ideally be sufficient to promote the development of at least 3 follicles beyond 18mm diameter at the time of OPU. This can be expected to result in at least 2 embryos to be available for transfer. Monitoring of follicular response by a combination of E2 and ultrasonic parameters is recommended so that the administration of HCG is given close to the anticipated endogenous rise of LH. This can be achieved by detecting a reduction in the rate of E2 rise (to plateau).(ABSTRACT TRUNCATED AT 250 WORDS)

Chorionic Gonadotropin↗
PubMed1983

Fate of cholesterol-rich liposomes after subcutaneous injection into rats.

The fate of small (30-60 nm) and large (about 400 nm diameter) liposomes composed of phosphatidylcholine or sphingomyelin and equimolar cholesterol and containing quenched carboxyfluorescein and 111In-labelled bleomycin after footpad injection of rats was investigated. Judging from the values of latent carboxyfluorescein in the plasma, phosphatidylcholine and sphingomyelin small liposomes entered the blood circulation intact, presumably via the lymphatics to reach 3 h after injection a peak of 16.9 and 23.1% of the dose per total blood, respectively. Of the 111In radioactivity given in phosphatidylcholine liposomes, about 32% was recovered in the liver. Hepatic uptake of 111In for sphingomyelin liposomes was lower (about 9%) reflecting their slower rate of clearance. No latent carboxyfluorescein could be detected in the blood after injection with phosphatidylcholine or sphingomyelin large liposomes and levels of 111In in the liver (and spleen) were very low. A proportionally much greater amount of liposomal 111In was intercepted by the popliteal and to a lesser extent, the lumbar lymph nodes. Such uptake was significantly higher (e.g. 463%) for small than for large (e.g. 195% per g popliteal nodes) liposomes. After foot pad injection of large liposomes into Walker 256 tumour-bearing rats, localization of 111In in the popliteal nodes was similar to that seen with control animals. However, 111In localization in the lumbar nodes was augmented more than 5-fold. These results suggest that large liposomes as used in this study, characterized by efficient drug entrapment, inability to reach the liver and spleen and improved localization in the lymph nodes of tumour-bearing animals may be preferable to vesicles of small size for the local treatment of lymphatic metastases.

Animals↗
PubMed1983

Incidence of multiple pregnancy after in-vitro fertilisation and embryo transfer.

7 multiple pregnancies occurred in a series of 20 pregnancies after oocyte recovery for in-vitro fertilisation and embryo transfer. After ovarian stimulation with clomiphene alone or with human menopausal gonadotropin, 102 laparoscopies were carried out in 62 women and the ongoing pregnancy rate beyond the first trimester was 17/102 laparoscopies (17%), including 5 sets of twins. 1 triplet and 1 twin pregnancy showed evidence of regression of two sacs and one sac, and both are progressing as singleton pregnancies at 16 and 34 weeks, respectively. 3 abortions occurred at 7, 8, and 9 weeks--a spontaneous abortion rate of 15%. The pregnancy and multiple pregnancy rates after stimulation with clomiphene alone or with human menopausal gonadotropin were comparable, but oocyte pickup based on a knowledge of the duration of the endogenous rise in luteinising hormone, rather than 36 h after administration of human chorionic gonadotropin, increased the pregnancy rate. As the quality and number of embryos transferred to the uterus increased, the risk of multiple pregnancy also rose. Consideration should therefore be given to restricting the number of embryos transferred to limit multiple pregnancies to twins.

Adult↗
PubMed1983

The effect of lipid composition of small unilamellar liposomes containing melphalan and vincristine on drug clearance after injection into mice.

Melphalan and vincristine together with their radiolabelled derivatives were entrapped in small unilamellar liposomes of varying cholesterol content and phospholipid composition. After intravenous injection of drug-containing egg phosphatidylcholine liposomes into mice, drug clearance rates from the blood were reduced with increasing cholesterol content. Circulating drugs were partially associated with the carrier and partly free, mostly bound to plasma proteins. The ratio of drug associated with liposomes to that circulating as free was dependent on the type of liposomes used and highest when these were cholesterol-rich. Drug clearance rates were reduced and entrapped: free drug ratios increased further when egg phosphatidylcholine in cholesterol-rich liposomes was replaced by sphingomyelin. Drug-containing cholesterol-rich liposomes injected intraperitoneally were found capable of entering the periphery intact and quantitatively to assume clearance rates similar to those observed after intravenous treatment. Such manipulations in liposomal lipid composition can alter pharmacokinetics in ways that could provide optimal conditions for drug distribution into tumours and a therapeutic effect.

Animals↗