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Biomedical subjects

K L Harrison

Publications and source records attributed to K L Harrison.

At least 37 records · Page 2Linked to original sources
PubMed1989

Patient age and success in a human IVF programme.

Previous studies suggest that at around 40 years of age, pregnancy rates achieved by IVF programmes fall and pregnancy loss rates increase. The actual age at which this occurs has not been clearly delineated. This study of 2,692 patients including 94 aged 41 or over shows that satisfactory pregnancy rates can be achieved up to and including age 40. As age 40 is approached the pregnancy loss rate increases to around 40%. In the 41 years and over group the pregnancy rate was poor at 6% (6/94) and the pregnancy loss rate very discouraging at 83% (5/6).

Adult↗
PubMed1988

Fertilization of human oocytes in relation to varying delay before insemination.

Fertilization and pregnancy rates in an in vitro fertilization and embryo transfer program were studied after a range of insemination times of between 1 and 26 hours after oocyte recovery. There was no significant variation in fertilization rate across this range. The pregnancy rate showed no significant variation for insemination between 3 and 16 hours after aspiration. However, it was disappointing at 2 hours (3%), and no pregnancies were achieved from the nine patients whose ova were inseminated 20 or more hours after aspiration. It is concluded that mature oocytes can be inseminated in vitro at any time between 3 and 16 hours after aspiration and still retain the same potential to produce a pregnancy.

Female↗
PubMed1987

Results using medium supplemented with either fresh or frozen stored serum in human in vitro fertilization.

This study retrospectively compared the success of in vitro fertilization (IVF) among patients whose gametes had been incubated either in medium supplemented with freshly prepared pooled serum (331 cases) or in pooled serum which had been stored at -20 degrees C prior to use (728 cases). Frozen stored serum was as effective as fresh serum with regard to the proportion of oocytes which fertilized and embryos which implanted and was not associated with any increased incidence of fetal loss during postimplantation development.

Blood Physiological Phenomena↗
PubMed1987

Stress and semen quality in an in vitro fertilization program.

While a greater understanding is emerging of the psychological stresses of infertility treatment, little is known about the specific effects of these stresses upon the quality of the semen sample used at the fertilization stage in an in vitro fertilization and embryo transfer (IVF-ET) program. This study evaluated two semen profiles for each of 500 couples on IVF treatment. The first semen sample was collected in the couple's pre-IVF workup, and the second sample was given by husbands after ovum aspiration, and used to inseminate the eggs in vitro. Comparisons of samples revealed that sperm density, total sperm count, and both quantitative and qualitative sperm motility were significantly lower in the second sample presented for IVF. For 91% of cases, there was no change across samples in assigned fertility index categories. However, 14 cases revealed a deterioration, falling from normal to pathologic, while 21 cases changed in semen character from normal in IVF workup to severely pathologic in IVF treatment. For these cases, the incidence of total fertilization failure in the procedure also dramatically increased. Several steps are discussed in the better management of patients with such declines in semen quality.

Fertilization in Vitro↗
PubMed1986

A formula for scoring human embryo growth rates in in vitro fertilization: its value in predicting pregnancy and in comparison with visual estimates of embryo quality.

Two systems for measuring embryo development in vitro were evaluated. One was a 1-4 scale based on a subjective evaluation of embryo quality (EQ) from microscopic appearance. In addition, a formula for scoring embryo growth rate in vitro was developed. The embryo development rating (EDR) was based on the ratio between the time at which embryos were observed at a particular stage after insemination and the time at which they would be expected to reach that stage in a hypothetical "ideal" growth rate with a cell cycle length of 11.9 hr. Using this scoring system, "normally" growing embryos scored 100. This approach was aimed at partially normalizing the data and allowed all embryos to be analyzed similarly regardless of the time of observation. Analysis of 1539 embryo replacements resulting in 232 clinical pregnancies showed that both EDR and embryo-quality scores were of value in predicting success, with clinical pregnancy most likely to eventuate from a combination of moderate to good EQ scores (2-4) coupled with average or above-average growth rates (EDR scores from 90 to 129). Poor-quality and very slowly or very rapidly growing embryos were underrepresented in cycles that proceeded to pregnancy. These inferences were based on all embryos transferred (mean, 2.73 per transfer cycle), and they were substantiated by an analysis of 33 pregnancies resulting from replacement of a single embryo and from 18 pregnancies in which all embryos scored the same with both systems. EQ and EDR were significantly associated with each other and together provide a valuable guide in predicting pregnancy, in selecting embryos for freezing, and in monitoring day-to-day performance in the in vitro fertilization (IVF) program.

Embryo Transfer↗
PubMed1984

Treatment of male sperm autoimmunity by in-vitro fertilization with washed spermatozoa.

Pregnancies have been achieved in two couples with prolonged infertility in whom no apparent abnormalities were found, except for the presence of seminal plasma autospermagglutinins in the male partners. Using a method previously advocated for artificial insemination by husband, the semen was collected directly into Tyrode's solution and immediately dispersed. After they were washed and resuspended in Tyrode's solution, the spermatozoa were used for the in-vitro fertilization of the wife's ova collected after induced ovulation. In a condition characterized by the difficulty of achieving sperm-ovum contact and interaction, this approach allows close monitoring of all stages of this process and appears to circumvent any expected difficulties.

Antigen-Antibody Reactions↗
PubMed1984

Value of maternal anti-D concentration in predicting the outcome of Rh(D) haemolytic disease.

The outcomes of 43 pregnancies complicated by the presence of Rhesus antibodies were studied in relation to the peak concentrations of anti-D reached during pregnancy. Antibody concentration was measured by an automated method calibrated against the British Anti-D Working Standard. Where the anti-D concentration remained below 5 IU/ml, the infants at worst suffered only moderate jaundice controllable with phototherapy. Above this level the incidence of requirement for exchange or top-up transfusion was high with concentrations greater than 50 IU/ml being predictive of a very severely affected fetus. It is recommended that amniocentesis in these patients be deferred until maternal anti-D levels exceed 5 IU/ml.

Autoanalysis↗
PubMed1981

Anti-C haemolytic disease requiring intrauterine and exchange transfusion.

A case is presented of anti-C haemolytic disease of the newborn in which the infant required three intrauterine transfusions and an exchange transfusion after birth. Anti-C is not a common cause of haemolytic disease of the newborn and this is the first recorded case requiring intrauterine transfusion.

Adult↗
PubMed1981

The effect of maternal smoking on carboxyhemoglobin levels and acid-base balance of the fetus.

Results are presented showing a dose-related effect of maternal smoking during pregnancy on cord blood carboxyhemoglobin levels. These elevated cord blood carboxyhemoglobin levels are associated with decreased pH and pO2 levels and raised pCO2 levels. This evidence of chronic intrauterine hypoxia in the infants of mothers who smoke during pregnancy provides a potential mechanism for the reduced birthweight found in these infants.

Acid-Base Equilibrium↗
PubMed1979

The effect of maternal smoking on neonatal leucocytes.

Results are presented showing an association of maternal smoking during pregnancy with a reduction in the numbers of circulating neutrophils in their infants. It is postulated that such infants may be more susceptible to infection.

Female↗