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Biomedical subjects

I Z Mackenzie

Publications and source records attributed to I Z Mackenzie.

At least 19 recordsLinked to original sources
PubMed2006

Induction of labour at the start of the new millennium.

Around 20% of all deliveries are preceded by labour induction, a proportion that has not varied dramatically over recent years. Fetal death was the only indication for labour induction centuries ago, while this is now a very rare indication, with prolonged pregnancy and maternal hypertensive disorders being the major indications for the last 50-60 years. Techniques for inducing labour have also changed from dietary delicacies and verbal threats giving way to physical stimulation mainly achieved by cervical stretching and amniotomy and more recently to sophisticated pharmacological manipulation using oxytocin and prostaglandins, based on our expanding knowledge of the physiological processes involved in spontaneous parturition. Relaxin, antiprogestins, nitric oxide as well as complementary medicines have also been explored in recent years. Successful induction is, however, still not guaranteed and there has been increasing emphasis during the past decade on exploring strategies for identifying the probability of success. Measurement of fetal fibronectin in cervical mucus, maternal serum nitrite/nitrate concentrations, ultrasound delineation of cervical form and electrical impedance measurements across the cervix are all being investigated. Safety, success, and patient satisfaction continue to be the major objectives with economic evaluations now becoming a significant factor in the search for the ideal induction method.

Amnion↗
PubMed2005

Does discussion of possible scar rupture influence preferred mode of delivery after a caesarean section?

Using retrospective and prospective analyses of antenatal records, it was found that by 2003, discussions about the options for delivery after one lower segment caesarean section (LSCS) were almost always documented in antenatal notes, compared with only rare entries in 1993; specific mention of the risks of scar rupture were made in just under 50% in 2003. There was a considerable reduction in the proportion of women whose preference was to labour in 2003 compared with 1993 and also in the number who ultimately delivered vaginally. There was, however, no evidence that those women with whom possible scar rupture had been discussed were discouraged from attempting vaginal delivery. These data suggest that, contrary to expectations, increasing patients' involvement in their management in this situation does not result in fewer caesarean sections.

Cesarean Section↗
PubMed2004

Efficacy of follow-up and contact tracing of women who test positive for genital tract chlamydia trachomatis prior to pregnancy termination.

We examined the efficacy of follow-up, contact tracing and the need for retreatment in women who were screen-positive for genital tract Chlamydia trachomatis prior to termination of pregnancy. Eighty-six of 1363 (6.3%) women screened positive. These women were significantly younger than those who screened negative (P < 0.0001). The genitourinary medicine (GUM) clinic was notified of 73 (84.9%) screen-positive women and 41 (47.7%) attended for follow-up. Contact tracing was undertaken in 38 (92.7%) women who attended and 29 (70.7%) women who attended required retreatment for Chlamydia. The median duration between pregnancy termination and GUM clinic attendance was significantly longer in women who required retreatment compared to those who did not require retreatment (P = 0.003). In conclusion, follow-up and contact-tracing of women who screen positive for genital tract C. trachomatis was incomplete. This may substantially compromise the cost-effectiveness of a screen-and-treat programme.

Abortion, Induced↗
PubMed1999

Patient satisfaction in gynaecological outpatient clinic attendances.

A questionnaire was used to assess patients' perception of and satisfaction with gynaecology outpatient appointment date and waiting times at gynaecology outpatient clinics. While 95% were satisfied with the overall service, 19% expressed dissatisfaction with waiting times for first appointment and 26% with the waiting time at the clinic. These findings are discussed in the light of the recommendations of the Patient's Charter and with respect to reorganising outpatient gynaecology services to improve efficiency.

Journal Article↗
PubMed1998

Validation of anti-vascular endothelial growth factor (anti-VEGF) antibodies for immunohistochemical localization of VEGF in tissue sections: expression of VEGF in the human endometrium.

Transient transfection of COS-1 cells followed by fixation, embedding in paraffin, and immunohistochemistry has identified anti-vascular endothelial growth factor (anti-VEGF) mouse monoclonal antibodies that efficiently immunostain VEGF in paraffin-embedded tissue sections. Immunohistochemical localization of VEGF in 34 specimens of normal human endometrium that had been collected at different stages of the menstrual cycle was then performed. VEGF was present at all stages of the cycle, but both the pattern and the intensity of staining varied. Thus, VEGF expression occurred predominantly in the endometrial epithelium and while weak in the proliferative phase, was strong in the secretory phase. VEGF expression in the stroma was weaker than in the proliferative phase glands and did not change throughout the cycle. These findings are in agreement with reports of VEGF mRNA expression in the endometrium, but disagree with previous immunohistochemical studies that employed an immunohistochemically unvalidated antiserum. This study has shown that the commercially available anti-VEGF monoclonal antibody M293 is excellent for the immunohistochemical localization of VEGF in paraffin sections.

Adenocarcinoma↗
PubMed1997

Stillbirth and caesarean section.

In one health region between 1991 and 1996, 105 (11%) of all stillbirths were delivered by caesarean section. Forty-eight (46%) were unexpected at the time of birth, two of whom were macerated. Most of the macerated stillbirths were one of a multiple pregnancy, while 22 of the fresh stillbirths were delivered by caesarean section prior to the onset of labour. Twenty-one caesarean sections were performed because of failed attempts to induce labour, or at the request of the mother. The unexpectedly high rate of stillbirths delivered by caesarean section could be reduced by improved methods and understanding of antenatal and intrapartum fetal monitoring and techniques for inducing labour.

Journal Article↗
PubMed1997

Regulation of the expression of the angiogenic enzyme platelet-derived endothelial cell growth factor/thymidine phosphorylase in endometrial isolates by ovarian steroids and cytokines.

The angiogenic enzyme platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) was strongly expressed in the endometrial glands in the luteal and menstrual, but not the proliferative, phases of the cycle. The converse was seen in the stroma, where expression was strong in the proliferative, but not the luteal or menstrual, phases. Inflammatory cytokines induced PD-ECGF/TP expression in primary cultures of human normal endometrial epithelial (NEE) and normal endometrial stromal cells. The profile of cytokine induction of PD-ECGF/TP was cell dependent. Thus, in NEE cells, PD-ECGF/TP expression was strongly induced by the combination tumor necrosis factor-a and interferon-gamma. In contrast, in normal endometrial stromal cells, interferon-gamma gave, by far, the strongest induction of PD-ECGF/TP. Expression of the enzyme was not regulated by ovarian hormones alone. Although treatment of NEE cells with a physiological concentration of progesterone (5 X 10[-8] M) or transforming growth factor-beta1 (10 ng/ml) alone had no effect on PD-ECGF/TP expression, when delivered together at the same dose they induced a 48-fold increase in expression. This expression correlates with cyclic changes in progesterone and transforming growth factor-beta1 levels in the uterus.

Adenocarcinoma↗
PubMed1994

Prenatal determination of fetal rhesus D status by DNA amplification of peripheral blood of rhesus-negative mothers.

We have developed a sensitive PCR-based assay for the RhD gene and used it to detect circulating fetal cells from RhD-positive fetuses from peripheral blood of RhD-negative mothers. With further improvement in diagnostic accuracy, this assay may have implications in the management of RhD-sensitized pregnancies in women whose partners are heterozygous for the RhD gene. Further studies are required to determine the relationship between maternal anti-D levels and circulating fetal cell numbers.

Amniotic Fluid↗
PubMed1992

Computerized measurement of heart rate variation in fetal anemia caused by rhesus alloimmunization.

OBJECTIVE: The purpose of this study was to examine the relationship between fetal heart rate variation and fetal hematocrit. STUDY DESIGN: In 36 red-cell alloimmunized pregnancies (mean gestational age 30, range 25 to 36 weeks) 65 computerized fetal heart rate recordings were obtained before ultrasonographically guided fetal blood sampling for the measurement of fetal hematocrit. The recordings were captured and analyzed by a microcomputer on-line. Fetal heart rate variation in anemic fetuses was accurately measured. RESULTS: Significant positive correlations between short-term or long-term heart rate variation and fetal hematocrit have been demonstrated even after adjusting for the effect of gestation (r = 0.60, n = 65, p less than 0.01, y = 19.264 + 0.913x - 0.003x2; r = 0.52, n = 65, p less than 0.01, y = 21.13 + 0.858x - 0.003x2, respectively). The relationship was best described by a quadratic model. When short-term variation was less than 5 milliseconds or long-term variation was less than 30 milliseconds, the positive predictive values for fetal hematocrit of less than 30 were 85% and 90%, and the negative predictive values 56% and 57%, respectively. CONCLUSION: Computerized recording and analysis of fetal heart rate variation may prove to be a useful noninvasive tool for assessing fetal anemia in red-cell alloimmunization.

Anemia↗
PubMed1992

A comparison of perinatal outcome, antenatal and intrapartum care between England and Wales, and France.

OBJECTIVE: To compare the national statistics of England and Wales with the national statistics of France, and see if there are significant differences in obstetric care resulting in a significantly different perinatal outcome. DESIGN: Retrospective analysis of national statistics 1970-1989 (latest available figures) relating to perinatal outcome, antenatal and intrapartum care. SETTING: HIPE and DoH statistics (England and Wales); INSERM statistics (France). SUBJECTS: Pregnant women residents of England and Wales, and of France. INTERVENTIONS: Different aspects of obstetric care for which comparable data were available from national statistics. MAIN OUTCOME MEASURES: Perinatal mortality rate, incidence of low birth weight and preterm delivery; type of antenatal care, number of antenatal visits and in-patient admission rate; induction of labour rate, incidence of acceleration of labour with oxytocin, incidence of spontaneous and operative deliveries and person undertaking delivery; episiotomy rate and postnatal in-patient stay. RESULTS: More antenatal intervention and marginally less intrapartum intervention in England and Wales as compared with France. No significant difference in the perinatal mortality rate, in the incidence of low birth weight or preterm delivery, with similar trends being observed over the two decades. CONCLUSION: Significant differences in obstetric practices between the two countries without a major difference in perinatal outcome.

England↗
PubMed1992

Folate and vitamin B12 concentrations in maternal and fetal blood, and amniotic fluid in second trimester pregnancies complicated by neural tube defects.

OBJECTIVE: To investigate maternal and fetal folate and vitamin B12 concentrations in pregnancies affected by neural tube defects (NTD). DESIGN: Measurement of folate and vitamin B12 concentrations in amniotic fluid, fetal blood and maternal blood samples in midgestation. SUBJECTS: 32 women undergoing termination of pregnancy at 14-21 weeks gestation for social reasons (n = 24) or for fetuses with neural tube defects (n = 8). INTERVENTIONS: Fetoscopy before intra-amniotic injection of prostaglandins. RESULTS: In normal pregnancies there was a positive correlation between maternal and fetal serum folate, and the fetal serum and red blood cell folate concentrations were higher than the maternal. There were no differences in amniotic fluid, maternal blood or fetal blood folate concentrations between pregnancies with NTD and normal pregnancies. Although amniotic fluid vitamin B12 was lower in pregnancies with NTD, maternal serum vitamin B12 concentration was not reduced. CONCLUSION: In this small group of pregnancies with NTD at mid-gestation there is no evidence to suggest folate or vitamin B12 deficiency.

Abortion, Spontaneous↗
PubMed1991

P29, an oestrogen receptor-associated protein, is down-regulated by mifepristone in first trimester human placenta and decidua.

P29 is an oestrogen receptor-associated protein which acts as a marker of oestrogen action in several systems. The concentration of P29 was measured in placenta and decidua from women following medical termination of pregnancy with the antiprogesterone steroid mifepristone (RU 38,486) and a prostaglandin E1 analogue, and compared with the concentration of P29 found in matched controls undergoing surgical aspiration of pregnancy. Oestrogen receptors were also measured in the same samples. Placental and decidual P29 concentrations (IU/mg protein) in patients treated with mifepristone were 9.6 (4.6-54) and 4.8 (1.3-13.3) (median and range), respectively. These values were significantly lower than the corresponding values, 39.5 (27-69) and 22.0 (2-107) in the surgical group. In contrast, the levels of oestrogen receptors did not change significantly in either decidua or placenta. These data show that mifepristone causes down-regulation of P29 in placenta and decidua, and therefore its action may disrupt oestrogen function in uterine tissues.

Abortion, Legal↗
PubMed1990

Limb reduction and chorion villus sampling.

Upper limb reduction was diagnosed by ultrasound scan at 17 weeks after chorion villus sampling at 9 weeks' gestation. Pregnancy was terminated and necropsy confirmed limb reduction in an otherwise normal fetus. The relationship of limb reduction to amniotic band syndrome is discussed.

Adult↗
PubMed1990

The physiological and clinical effects of progesterone inhibition with mifepristone (RU 486) in the second trimester.

A double-blind placebo-controlled trial was performed in 20 primigravidae to assess the physiological and clinical effects of oral mifepristone on myometrial contractility and sensitivity in the second trimester. Ten women received 600 mg of oral mifepristone and 10 women a placebo 24 h before abortion was induced in both groups, with extra-amniotic PGE2 instillation. Intrauterine pressure recordings demonstrated increased spontaneous uterine activity and increased sensitivity to PGE2 and ergometrine, but no change in oxytocin sensitivity after mifepristone treatment. There were no significant differences in PGE or PGF metabolite concentrations in peripheral maternal plasma over the 24-h study period after treatment between the mifepristone and placebo groups. The mean induction abortion interval in the mifepristone group was 512 (SD 321) min compared with 1128 (SD 606) min in the placebo group (P less than or equal to 0.02). The mechanism whereby mifepristone provokes enhanced uterine contractility and sensitivity to prostaglandins, with a reduction in abortion times, does not appear to be through endogenous production of PGE or PGF.

Abortion, Induced↗