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Biomedical subjects

I A Greer

Publications and source records attributed to I A Greer.

At least 127 records · Page 7Linked to original sources
PubMed1994

Increased concentrations of cytokines interleukin-6 and interleukin-1 receptor antagonist in plasma of women with preeclampsia: a mechanism for endothelial dysfunction?

OBJECTIVE: To determine if plasma concentrations of defined cytokines are increased in women with preeclampsia, and to correlate any increases with the elevated concentrations of the vascular cell adhesion molecule (VCAM)-1. METHODS: Twenty primigravidas with preeclampsia were compared to 20 healthy primigravidas. Plasma levels of cytokines, tumor necrosis factor-alpha (TNF alpha), interleukin (IL)-6, IL-8, IL-1 beta, IL-1 receptor antagonist (IL-1ra), granulocyte macrophage-colony-stimulating factor (GM-CSF), and VCAM-1, were measured by enzyme-linked immunosorbent assay. RESULTS: Concentrations of IL-6 and IL-1ra were significantly higher (P < .01) in preeclamptic women (2.56 and 251.85 pg/mL, respectively) compared to normal pregnant patients (2.06 and 142.00 pg/mL, respectively). There were no significant changes in concentrations of TNF alpha, IL-8, GM-CSF, and IL-1 beta in preeclamptic patients (14.09, 50.52, 125.8, and 2.08 pg/mL, respectively) compared to normal patients (11.96 44.46, 121.3, and 2.01 pg/mL, respectively). Serum concentrations of VCAM-1 were increased in women with preeclampsia (preeclamptic group 841.9 +/- 49.7 ng/mL, control group 560.2 +/- 47.9 ng/mL; t = 3.673, P < .001). Interleukin-6 and IL-1ra concentrations correlated with VCAM-1 concentrations (IL-6: r = 0.539, z = 2.9, P < .005; IL-1ra: r = 0.451, z = 2.428, P < .02). CONCLUSIONS: Increased cytokine concentrations may contribute to the endothelial damage that occurs with preeclampsia and may explain the mechanism underlying leukocyte activation in this disorder. The increased cytokine concentration may also be responsible for the endothelial adhesion that accompanies preeclampsia.

Adult↗
PubMed1994

Mechanical stretch increases proto-oncogene expression and phosphoinositide turnover in vascular smooth muscle cells.

OBJECTIVE: To determine whether changes in haemodynamic load, simulated in vitro by mechanically stretching cultured vascular smooth muscle cells, could be transduced into biochemical signals similar to those produced by growth factors. DESIGN: A system was developed which was capable of stretching cultured vascular smooth muscle cells from 0 to 20%. The effect of stretching quiescent vascular smooth muscle cells on both c-fos messenger RNA (mRNA) expression and release of total inositol phosphates was determined over a time interval of 0-360 min. METHODS: Rat mesenteric artery vascular smooth muscle cells were grown using standard cell culture methods. Induction of the proto-oncogene, c-fos, was determined by Northern blotting. Phosphoinositide breakdown was assessed by measuring [3H]-inositol phosphates released from prelabelled cells. RESULTS: A 20% fixed stretch resulted in a rapid induction of c-fos mRNA which reached maximal levels by 15 min. The amount of c-fos mRNA detected was dependent on the degree of stretch, with maximum induction obtained for 15 and 20% stretch. The effects of mechanical stretch were also assessed on phosphoinositide turnover by measuring [3H]-inositol phosphates released from prelabelled cells. A 20% fixed stretch of vascular smooth muscle cells for 20 min resulted in a 3.2-fold increase in total [3H]-inositol phosphates released compared with unstretched cells. CONCLUSIONS: Our results show that mechanical stretch increases proto-oncogene expression and phosphoinositide turnover in vascular smooth muscle cells in vitro. These observations suggest that mechanical stretch and growth factors share common signal transduction pathways which may be important in the development of vascular hypertrophy.

Animals↗
PubMed1993

The effect of introduction of umbilical Doppler recordings to obstetric practice.

OBJECTIVE: To assess the effect on obstetric practice of clinician access to umbilical artery Doppler ultrasound results. DESIGN: Randomised controlled trial. SETTING: A large teaching hospital. SUBJECTS: Two thousand two hundred and eighty-nine pregnancies defined as being at risk by referral for Doppler or fetal monitoring. INTERVENTIONS: Continuous wave Doppler studies of umbilical artery. Results immediately available to clinicians. MAIN OUTCOME MEASURES: Fetal outcome: perinatal mortality, Apgar score and admission to the neonatal unit. Obstetric intervention: admission to hospital, induction of labour and caesarean section. Use of of fetal well being: cardiotocography, biophysical profile and ultrasound biometry. RESULTS: The treatment and control groups were comparable in age, parity, gestation at point of entry and risk features. There were no overall differences in perinatal outcome, obstetric intervention or use of fetal monitoring. Examination of a subset recruited only because of hypertension or suspected intrauterine growth retardation (n = 754) similarly showed no difference attributable to group randomisation. Comparison of only those pregnancies retrospectively defined as low risk and high risk showed more use of cardiotocography in the high risk group with access to Doppler (P = 0.007) but no difference in the low risk group. CONCLUSION: Doppler umbilical artery recording has been shown to perform well in prediction power of antenatal fetal compromise. What has been examined in this study is the response of clinicians to the test. The results suggest that obstetricians do not use the test to modify their risk assessment, and, therefore, the need for fetal monitoring in particular pregnancies. There is a real need for accumulation of information from very large data sets, particularly in the prediction power of Doppler for antenatal fetal compromise from apparently chronic utero-placental cause to guide use of monitoring resources. If simply added to existing fetal monitoring techniques in a hospital where these are widely used, then umbilical artery Doppler recordings may at present simply involve extra resources of staff and expenses, without benefit.

Adult↗
PubMed1993

Plasma prostaglandin metabolite concentrations in normal and dysfunctional labour.

OBJECTIVE: To determine the concentrations of the metabolites of prostaglandin E2 (PGEM) and of prostaglandin F2 alpha (PGFM) prior to the onset of labour and during spontaneous labour, and to correlate the changes in concentrations of these metabolites with labour outcome. DESIGN: Longitudinal study throughout labour. SETTING: Labour ward of a large maternity unit. SUBJECTS: Seven primigravid and 11 parous women in the late third trimester with no signs of labour, and 17 primigravid and 11 parous women in spontaneous labour. INTERVENTIONS: Six of the primigravid women required augmentation with oxytocin because of dysfunctional labour. RESULTS: Before labour, parous women had significantly higher concentrations of both PGEM (P < 0.007) and PGFM (P < 0.006) compared with primigravid women. During labour, PGFM concentrations were significantly higher in both primigravid (P < 0.0002) and parous (P < 0.0001) women compared with the concentrations of these metabolites in women not in labour; the same was true for PGEM in primigravid (P < 0.003) but not in parous (P = 0.1) women. There was a small but significant increase (P < 0.02) in PGEM as labour progressed in both the normal groups. Amniotomy was associated with a significant increase in PGFM in primigravid and parous women (P < 0.002 and P < 0.009, respectively). The concentration of PGFM one hour following amniotomy correlated inversely with the amniotomy to delivery interval in both the normal primigravid (r = -0.624; P = 0.04) and the parous (r = 0.745; P = 0.021) groups. Women with dysfunctional labour showed no significant rise in PGEM or PGFM. Their PGFM concentrations were significantly lower than those seen in normal labour (P < 0.05). The concentration of PGFM in cord blood was significantly higher (P < 0.0001) in the parous women who laboured than in women delivered by elective caesarean section. There was no difference in the corresponding concentrations of PGEM (P = 0.9). CONCLUSIONS: These data show that spontaneous labour is associated with increased concentrations of prostaglandin metabolites in the maternal plasma, and are consistent with PGF2 alpha being an important stimulator of uterine contractility, with a relative deficiency of PGF2 alpha being associated with dysfunctional labour.

Adult↗
PubMed1993

Fetal growth, gestation length and phosphoglucomutase-1 phenotype.

This study investigates reports that phosphoglucomutase-1 (PGM1) phenotype is associated with fetal growth and gestation length. A total of 350 women were studied, 234 having uncomplicated pregnancies and 114 with a baby weighing greater than 90th centile, corrected for parity, gestation and fetal sex. All women had gestation confirmed by early ultrasound. Conventional cellulose acetate electrophoresis was used to distinguish the three common PGM1 phenotypes and polyacrylamide gel isoelectric focusing to distinguish the ten PGM1 subtypes. Neither PGM1 phenotype nor subtype were found to be associated with gestation length or standardised birth weight. Logistic regression, where maternal age, parity, fetal sex, maternal weight, gestation and smoking were introduced as explanatory variables in addition to PGM1 phenotype testing against the dependent variables birth weight, standardised birth weight and gestation length, did not show differences related to PGM1 phenotype. Two possible reasons for the discrepancy with previously published data are discussed. We conclude that the study provides no support for the belief that PGM1 phenotype is related to fetal growth or gestation length and that the original observations could have arisen as a result of statistical artefact due to multiple testing.

Biomarkers↗
PubMed1992

Gemeprost-induced cervical ripening: histological and biophysical effects.

The mechanism of prostaglandin-induced cervical ripening is not clear. The aim of this study was to measure the biophysical and histological effects of gemeprost on the cervix. Thirty-four women admitted for surgical termination of pregnancy in the first trimester were randomised in a double-blind manner to receive either gemeprost or placebo prior to surgery. In 20 (10 active, 10 placebo) a needle biopsy was taken from the anterior lip of the cervix prior to cervical dilatation for histology. The forces required to dilate the cervix from 3 mm to 10 mm were measured. A group of seventeen parous women undergoing surgical termination who did not receive gemeprost were also studied as a parous control group. A needle biopsy was obtained in eight of them and also in six non-pregnant parous women undergoing hysterectomy for benign conditions, the latter acting as a non-pregnant control group. Polymerised collagen was stained with Picrosirius red and glycosaminoglycans with alcian blue using a MgCl2 gradient. Optical densitometry was used as an objective measure of staining. Neutrophil concentration was assessed immunohistochemically. Gemeprost treatment increased free passibility (the size of the largest dilator which could be passed without encountering resistance) (P < 0.01), reduced the forces required to dilate the cervix (P < 0.01) reduced blood loss (P < 0.05), reduced the collagen concentration (P < 0.01) and was associated with a modest neutrophil influx (P < 0.02) as compared to placebo. The pregnant parous group had a significantly lower collagen concentration than the non-pregnant parous group (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Induced↗
PubMed1992

Prostaglandins and the cervix.

The dramatic capabilities of prostaglandins to modify the condition of the uterine cervix have been exploited to the considerable benefit of patients who require therapeutic interventions for labour induction and termination of pregnancy. This will continue to be an important facet of clinical obstetric and gynaecologic practice, although further refinements and improvements in techniques seem certain to continue.

Abortion, Therapeutic↗
PubMed1992

The effect of pH on release of PGE2 from vaginal and endocervical preparations for induction of labour: an in-vitro study.

OBJECTIVE: To study the effect of pH and precoating with obstetric cream on the release of prostaglandin E2 (PGE2) from commercially available triacetin and starch based gels, lactose based vaginal tablets and sustained release hydrogel polymer pessaries in-vitro. DESIGN: A prospective observational study. METHODS: PGE2 preparations held in dialysis bags were placed in Ringers lactate buffer and release of PGE2 into the buffer was measured over 8-12 h by radioimmunoassay. The hydrogel polymer pessary was also assessed after precoating with obstetric cream. MAIN OUTCOME MEASURES: In-vitro PGE2 release at pH 7.4, pH 5.4 and pH 3.4. RESULTS The gel preparations provided rapid and reliable release, while the lactose based vaginal tablet provided much lower release of PGE2 with sudden and variable release occurring after 5-8 h, an effect which was enhanced at low pH. With the triacetin gel preparation, release of PGE2 was reduced at lower pH, while the starch based gel appeared to provide optimal release at pH 5.4. The hydrogel polymer pessaries provided linear release in-vitro and this was reduced at pH 3.4. In addition, precoating the sustained release hydrogel polymer pessaries with obstetric cream virtually abolished release of PGE2. CONCLUSIONS: As the vagina is normally acid, these results suggest that vaginal pH could influence PGE2 release and this may result in variable clinical responses. In view of this, pH should be taken into account in the development of preparations for clinical use. Furthermore, the use of obstetric cream should be avoided when administering PGE2 preparations for induction of labour.

Cells↗
PubMed1992

Doppler umbilical artery flow velocity waveforms in diabetic pregnancy.

OBJECTIVE: To assess the effect of uncomplicated diabetes on umbilical artery flow velocity waveforms (FVWs); to investigate the relation between glycaemic control and FVWs and the predictive value of umbilical artery FVWs for antenatal fetal compromise. DESIGN: Prospective descriptive study. SETTING: A large diabetic pregnancy clinic in a teaching hospital. SUBJECTS: 128 pregnancies complicated by diabetes mellitus. 170 non diabetic women with no pre-existing or pregnancy complications. INTERVENTIONS: In diabetic pregnancies, umbilical artery resistance index (RI) Doppler recordings and glycosylated haemoglobin were measured every 2 weeks from 28 weeks. MAIN OUTCOME MEASURES: Umbilical artery RI and antenatal fetal compromise defined as a non reactive, decelerative cardiotocograph and/or a biophysical profile score persistently less than 6 and leading to immediate caesarean section. RESULTS: Uncomplicated diabetic pregnancies had FVW values similar to those in the non-diabetic range. Glycaemic control was unrelated to umbilical artery FVW values. Abnormal umbilical artery RI was found in nine pregnancies, these were more likely to show evidence of fetal compromise and to be associated with birthweights of less than 50th centile. In seven pregnancies there was evidence of fetal compromise, but only three of these pregnancies had abnormal FVW values. CONCLUSIONS: The non-diabetic range of umbilical artery RI values is appropriate for diabetic pregnancies. Long-term glycaemic control, within the range in this study, does not seem to affect umbilical artery RI. Abnormal umbilical artery RI is a significant predictor of fetal compromise in diabetic pregnancy, but fetal compromise can occur in association with normal RI values. Undue reliance should not be placed on normal FVW values in diabetic pregnancies.

Apgar Score↗
PubMed1992

Dexamethasone inhibits basal and stimulated prostaglandin E2 output from human placental cells by inhibition of prostaglandin H synthase.

In view of the temporal relation between elevated concentrations of glucocorticoids and prostaglandins (PG) at the time of parturition, we have examined the effects of dexamethasone on PGE2 output by mixed cell preparations from human placentae at term maintained in short-term (48 or 96 h) culture. Dexamethasone inhibited placental PGE2 output in a dose-dependent fashion. The effect on placental cells was more marked than on short-term cultures of amnion cells and was not influenced by the presence of progesterone. Dexamethasone also inhibited stimulated PGE2 output after addition of arachidonic acid. These results suggest that glucocorticoids inhibit placental PG output by a mechanism involving attenuation of PG synthase activity or expression and do not support a direct causal role for elevated maternal or fetal glucocorticoids at term on increased placental PG biosynthesis.

Arachidonic Acid↗
PubMed1991

Haemorrhagic problems in obstetrics and gynaecology in patients with congenital coagulopathies.

OBJECTIVE: To review the obstetric and gynaecological problems in women with congenital coagulopathies. DESIGN: Retrospective review. SETTING: Regional Adult Haemophilia Unit, Glasgow Royal Infirmary. SUBJECTS: All women in contact with the Unit over a period of 30 years, comprising eight with von Willebrand's disease, 18 obligate carriers of haemophilia A and five obligate carriers of Christmas disease. Each woman was interviewed and details of their obstetric and gynaecological histories were obtained and their case records were reviewed. MAIN OUTCOME MEASURES: Haemostatic changes associated with pregnancy and gynaecological problems. RESULTS: In 14 pregnancies in seven patients with von Willebrand's disease, there were four primary and four secondary post-partum haemorrhages and a large perineal haematoma complicating an episiotomy. These problems arose despite the endogenous rise in factor VIIIc seen with pregnancy. All women seen with von Willebrand's disease complained of menorrhagia and had been referred to gynaecologists. Treatment included danazol, tranexamic acid and the contraceptive pill. Diagnostic curettage resulted in severe haemorrhage in one woman and two women with pelvic pain and dyspareunia were found to have spontaneous broad ligament haematomas, one requiring surgery. In 43 pregnancies in obligate carriers of haemophilia A and Christmas disease there were five post-partum haemorrhages and a large perineal haematoma. CONCLUSION: In von Willebrand's disease it should be noted that adequate laboratory correction of factor VIIIc levels does not ensure clinical haemostasis; hence platelet function should also be measured. Patients with congenital coagulopathies pose particular problems for the obstetrician and gynaecologist and should be managed in close association with the local haemophilia centre.

Blood Coagulation Disorders↗
PubMed1991

Immunocytochemical localization of neutrophil elastase in term placenta decidua and myometrium in pregnancy-induced hypertension.

OBJECTIVE: The aim of the study was to determine whether there was evidence of elastase containing neutrophils at the materno-fetal interface in women with pregnancy-induced hypertension (PIH). DESIGN: An observational prospective study. SETTING: The Simpson Memorial Maternal Pavilion Edinburgh. METHODS: Placentas were obtained at vaginal or abdominal delivery from 51 consecutive women, 23 had normal pregnancies (13 caesarean sections) and 28 had PIH (18 caesarean sections). An immunocytochemical technique was used to localize elastase containing neutrophils in the placenta, decidua and myometrium. MAIN OUTCOME MEASURES: The numbers of positively stained cells, estimated subjectively as minimal, moderate or heavy, in subchorionic plate, perivillous fibrin and decidua. RESULTS: In both normal and PIH pregnancies neutrophils were absent from the myometrium. However, elastase containing neutrophils were located in areas of fibrin in the subchorionic plate and around the villi although there was no significant difference between the normal and PIH group. Neutrophils were also located in the fibrin of the decidua and in this case the number was significantly greater in the PIH group than in the normal group and correlated with plasma urate. CONCLUSION: The release of neutrophil elastase in the decidua could contribute to the vascular damage evident in PIH.

Adult↗