The expression of placental soluble fms-like tyrosine kinase 1 in mouse placenta varies significantly across different litters from normal pregnant mice.

OBJECTIVE: Gene expression studies often pool tissues from multiple placentas when using animal models of preeclampsia without accounting for the potential confounders of litter origin or pup sex. We aimed to determine whether placental gene expression differs based on sex or litter. METHODS: We examined the differential expression of soluble fms-like tyrosine kinase 1 (Flt-1) using 35 pups from six normal pregnant mice. RESULTS: Expression of sFlt-1 (p = 0.003) was significantly different between litters but not between sexes (p = 0.17). CONCLUSIONS: These findings highlight the importance of adequate sampling from multiple litters in expression studies when using animal models in clinical research.

OS010. Use of retinal imaging to characterise physiological vascularchanges throughout pregnancy.

INTRODUCTION: Visualisation of the microcirculation through retinal imaging can provide information on the health of systemic vasculature. Characterisation of the retinal vasculature throughout pregnancy using retinal imaging is a novel approach to examine physiological changes to the cardiovascular system, and may be useful to predict early pathophysiological signs of adverse maternal outcomes. OBJECTIVES: To characterise the retinal vascular and blood pressure (BP) changes that occur throughout a healthy pregnancy. METHODS: Data was collected from women recruited at 13±2 weeks of gestation from Royal Prince Alfred Hospital, a major tertiary referral hospital in Sydney, Australia. Retinal images centred on the optic disc and BP readings were collected throughout pregnancy. Postnatal data was collected from medical records, and women with hypertensive disorders of pregnancy and gestational diabetes mellitus were excluded. This left a final group of 19 women. Retinal images from 13±2, 19±2, 29±2 and 38±2 weeks gestation were graded using semi-automated retinal vascular calibre measurement (IVAN) software and the central retinal arteriolar equivalent (CRAE), and central retinal venular equivalent (CRVE). BP data was collected at the same time points as the retinal images. Analysis of data was performed using paired t-tests and repeated measures analysis of variance (ANOVA). Women with missing data points were excluded from the analysis at the relevant time points. RESULTS: Over the course of pregnancy, there was a significant dilatation of retinal arterioles between 13±2 and 19±2weeks (from 166.4 to 172.7µm, SE: 3.7µm, n=19, p=0.01), corresponding to a significant fall in diastolic BP during this time (from 64.6 to 60.2mmHg, SE: 1.5mmHg, p=0.01). No significant changes in venular diameter or systolic BP were noted. Between 19±2 and 29±2weeks (n=4), no significant changes to retinal arteriolar or venular diameter were seen although there were significant increases in both systolic and diastolic BP (SBP: from 100.3 to 109.9mmHg, SE: 1.9mmHg, p=0.01; DBP: from 59.3 to 64.6mmHg, SE: 6.9mmHg, p=0.01). Between 29±2 and 38±2weeks (n=3), no significant changes in retinal arteriolar, and venular diameter or BP were observed. CONCLUSION: An increase in retinal arteriolar diameter between 13±2 and 19±2 weeks gestation was observed, which corresponded to a decrease in both systolic and diastolic BP. However, between 19±2 and 29±2 weeks there was no change in vasculature, even though there was a significant increase in BP. By characterising the changes to retinal vessels that occur throughout a healthy pregnancy, we can further our understanding of the response of the systemic vasculature to pregnancy, which may provide clues to early vascular disease of pregnancies.

OS016. Retinal vascular changes in hypertensive disorders of pregnancy.

INTRODUCTION: Hypertensive disorders of pregnancy (HDP) are characterised by vascular dysfunction. Retinal vascular imaging is a novel, non-invasive way to characterise early microvascular changes in pregnancy, and as a result has the potential to be used to predict the onset of HDP. OBJECTIVES: To characterise retinal vascular changes that occur in HDP, and compare these changes to those in healthy pregnancies. METHODS: Women were recruited at 13±2 weeks of gestation from Royal Prince Alfred Hospital, a major metropolitan tertiary referral hospital in Sydney, Australia. Retinal images centred on the optic disc and blood pressure (BP) readings were collected at 13±2, 19±2, 29±2 and 38±2 weeks gestation. Retinal images were graded using semi-automated retinal vascular calibre measurement software (IVAN) and the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated. Within and between subject repeat measures analysis was performed on images from each trimester, using paired t-tests and repeated measures analysis of variance (ANOVA). Multiple linear regressions were used to model the average arteriole diameter adjusted for age, tobacco consumption and body mass index (BMI). All tests were two-sided using a 5% level of significance. A clinical diagnosis of HDP was obtained from postnatal medical record data. Women with missing data points were excluded from the analysis at that time point. RESULTS: Of the 39 women included in the study, 6 (15%) were diagnosed with HDP. In the HDP cohort, repeated measures ANOVA revealed no significant changes in arteriolar or venular diameter measurements throughout pregnancy. Paired t-tests indicated no significant differences in any of the outcome measures between HDP and healthy pregnancies at 13±2 (n=36) and 19±2 (n=39)weeks. At 29±2weeks (n=39), there was a significantly smaller venular diameter in HDP pregnancies (220.4±6.9µm vs 239.1± 5.4µm in healthy pregnancies, p=0.03). At 38±2weeks (n=39), arteriolar diameter was significantly smaller in HDP pregnancies (148.6±6.0µm vs 164.1±4.6µm in healthy pregnancies, p=0.04). Similar results persisted following adjustments for cardiovascular risk factors (age, tobacco use and BMI). CONCLUSION: Significant differences in the retinal vasculature develop in HDP as compared to healthy pregnancies. These differences appear at29±2weeks gestation and persist throughout the rest of the pregnancy. Retinal vascular imaging is a promising tool for the detection of the early microvascular changes in HDP, prior to diagnosis.

OS055. Sex-dependent differences in expression of FLT-1 variants andJMJD6 in mouse placenta.

INTRODUCTION: There is evidence for fetal sex-dependent differences in the way in which preeclamptic pregnancies proceed, and in maternal and neonatal outcomes. Mouse models are common in the study of preeclampsia and pooled tissue from multiple placentae is often used to obtain samples for expression studies. Potential concerns regarding this practice are the sex-dependent differences in placental expression of candidate factors. One biomolecule of interest is soluble fms-like tyrosine kinase 1 (sFLT-1) which is a known marker of preeclampsia and commonly used to determine the severity of the induced preeclampsia-like syndrome in rodent models. OBJECTIVES: It was the aim of this preliminary study to determine whether variation exists in the expression of different genes in murine placenta based on pup sex in C57BL/6JArc mice. A novel gene, Jumonji domain-containing protein 6 (Jmjd6) that may prove to have a role in the pathogenesis of preeclampsia, mFLT-1 and sFLT-1 were selected as targets. METHODS: Seventeen pups were retrieved from three normal pregnant female mice euthanized via cervical dislocation (CD) on day 17.5 or 18.5. Tails and corresponding placentas were collected from the pups, snap frozen in liquid nitrogen and stored at -80°C. Tails were used to accurately determine pup sex via PCR amplification of sex chromosome-specific sequences and revealed the presence of 3 females and 14 males. Quantitative PCR was used to determine the relative expression of the FLT-1 and Jmjd6 transcripts in each placenta. The placenta collected from the first pup of the first pregnant female served as the reference sample and transcript expression in the remaining samples was expressed relative to this sample. General linear modelling using linear regression with categorical variables was used to evaluate the difference in transcript expression between the sexes and Pearson's correlation coefficient used to examine relationships between variables. RESULTS: Pup sex was found to have a significant effect on the relative expression of sFLT-1 after controlling for litter, pup weight and gestational age (p=0.013), with 1.5 times more expression in the placentas of female pups. The expression of sFLT-1 was highly correlated with mFLT-1 (r=0.690,p=0.002). The relative expression of Jmjd6 was not significantly different in male and female placentas and sFlt-1 was not correlated with Jmjd6. CONCLUSION: This is the first study to demonstrate a link between fetal sex and placental sFLT-1 expression in mice, finding increased levels of this gene in the placentas of female pups. It is possible that in normal pregnancies, female placentas produce more sFLT-1 which acts to condition them and offer some protection during the sFLT-1 spike seen in preeclampsia. The findings of this study also highlight a possible need to consider sex as a variable in placental expression studies using mice to ensure the accuracy of results.

PP001. Variability in MRNA expression of Jmjd6 and FLT-1 variants in normal and preeclamptic human placenta.

INTRODUCTION: Biomolecules such as soluble fms-like tyrosine kinase 1 (sFLT-1) have been implicated in the pathogenesis of preeclampsia with many studies reporting on their expression in human placenta. OBJECTIVES: This study aimed to determine whether variation exists in the expression of different genes in human placenta based on collection site. Expression of different FLT-1 variants including the primate-specific sFLT-1e15a and a novel gene, Jumonji domain-containing protein 6 (Jmjd6) that may prove to have a role in the pathogenesis of preeclampsia, was selected as targets. METHODS: Placental tissue was collected from one normotensive and one preeclamptic woman following caesarean section at 38 weeks. Twelve 1.5cm diameter×2mm thick samples were excised from various sites around the decidual surface. Quantitative PCR was used to determine the relative expression of the FLT-1 and Jmjd6 transcripts in the separate samples. Within a placenta, the first sample collected served as the reference and transcript expression in the remaining 11 samples was expressed relative to this sample. Between placentas, a pooled normal sample was used as a reference to determine the relative expression in preeclamptic compared to normal placental samples. One sample t -tests and coefficients of variation (CV) were used to explore the variation and Pearson's correlation coefficient was used to examine relationships. RESULTS: Within the normal placenta, significant variation was seen in the 12 collection sites for sFLT-1 e15a (CV=45.1% p=0.008) and Jmjd6 (CV=30.4% p=0.019). The CVs for sFLT-1 i13 and mFLT-1 were 25.6% and 23.7% respectively. Within the preeclamptic placenta, significant variation was seen in the expression of all FLT-1 variants; mFLT-1 (CV=66.9% p=0.023), sFLT-1 i13 (CV=64.8% p=0.033) and sFLT-1 e15a (CV=61.1% p=0.001) across different collection sites. Significant variation was also seen between preeclamptic placenta sites and a normotensive pool; mFLT-1 (CV=66.9% p=0.012), sFLT-1 e15a (CV=61.1% p=0.005) and Jmjd6(CV=65.2% p=0.029). Using cumulative moving means, the minimum number of samples required to obtain a zero difference in means for all transcripts in a data subset was 8 for the normal placenta and 6 for the preeclamptic placenta. Overall, the expression of Jmjd6 and all FLT-1 variants was increased in the samples from the preeclamptic placenta compared to normal. Expression of mFLT-1 was highly correlated with sFLT-1 i13 and sFLT-1 e15ain preeclamptic (r=0.808 p=0.001; r=0.841p=0.001) but not normal placenta, and Jmjd6 was not correlated with any transcript in either placenta. CONCLUSION: This study demonstrates significant variation in expression levels of several new and commonly investigated genes across sites in both normal and preeclamptic human placenta. These data show samples should be obtained from no less than 8 separate sites when pooling samples for expression analysis. Further, given that many studies examine relationships between different colocalised molecules, it may also be prudent to examine expression levels in each site separately to ensure that no relationships are missed.

PP033. High blood pressure in pregnancy: an indicator of future health outcomes.

INTRODUCTION: Hypertensive disorders of pregnancy (HDP) remain a leading cause of maternal and perinatal morbidity and mortality worldwide. In Australia approximately 10% of all pregnancies are affected by HDP. There is growing evidence that endothelial damage caused by HDP remains after pregnancy and has long term consequences on maternal health. OBJECTIVES: The aim of our research was to determine the association between HDP and risk of having high blood pressure in later life. METHODS: Self-reported data regarding a physician's diagnosis of HDP and of high blood pressure later in life were obtained from women recruited from the 45 and Up Study, Australia. Relative risks (converted from odds ratios) and 99% confidence intervals were estimated using logistic regression, adjusting for demographic and lifestyle characteristics. RESULTS: A total of 82,164 women were included in the study, of which 9,845 reported having HDP. Women who had HDP had a significantly increased risk of having high blood pressure later in life compared to women who did not have HDP (adjusted relative risk of 2.05, 99% CI 1.99-2.11, p<0.001). The results showed that women who had HDP develop high blood pressure 6.3 years (99% CI 5.85-6.66, p<0.001) earlier compared to women without HDP. CONCLUSION: Women who have HDP are at a greater risk of future onset of high blood pressure compared to women who have a healthy pregnancy. Women with HDP should be monitored closely in the years following pregnancy for early identification and intervention of high blood pressure.

Impact of bispectral index monitoring on propofol administration in patients undergoing cardiopulmonary bypass.

Propofol anaesthesia using target control infusion during cardiac surgery has become more popular recently. However, without depth of anaesthesia monitoring, the standard target concentration used may be higher than necessary to maintain adequate hypnosis during hypothermic cardiopulmonary bypass. The purpose of this study was to evaluate the effect of bispectral index monitoring on propofol administration during hypothermic cardiopulmonary bypass. After ethics committee approval and written informed consent, 20 New York Heart Association class I-III patients scheduled for elective cardiac surgery requiring hypothermic cardiopulmonary bypass were studied in this prospective randomised controlled trial. In group C, routine anaesthesia was practised, where patients received propofol at target concentration between 1.5 to 2.5 microg/ml during cardiopulmonary bypass. In group B, the target concentration was titrated to a bispectral index value of 40 to 50. Mean arterial pressure and bispectral index were recorded at various time intervals. The use of propofol, phenylephrine, sodium nitroprusside and adrenaline were recorded. The median propofol administration in group B was significantly less than that in group C (2.9 mg/kg/h compared to 6.0 mg/kg/h). The bispectral index value during bypass was significantly lower in group C than in group B, reflecting a deeper state of anaesthesia. There was no difference in the use of inotropes, vasoconstrictors or vasodilators. Bispectral index monitoring enables a 50% reduction in propofol administration at this standard dose during hypothermic cardiopulmonary bypass.

The contents and forms of solid-phase species of radioactive strontium and cesium in Taiwan soils.

This study was to investigate the activities and contents of (137)Cs in the profiles of selected arable and forest soils in Taiwan and various solid-phase species of (85)Sr and (137)Cs in selected arable soils in Taiwan. The gamma (gamma) ray spectra of the collected soil samples and some of the soils amended with (85)Sr and (137)Cs were measured. The data indicate that the arable soils from Sanhsing series, Sanhsing Township and Chuangwei series, Chuangwei Township, Ilan County, and from Tunglochuan series, Pinglin Township, Taipei County shows significantly higher radioactivity of (137)Cs (ND - 11.0 +/- 0.2 Bq kg(-1)). Furthermore, the radioactivity of (137)Cs in the mountain soils (1.24 +/- 0.07 - 42 +/- 1 Bq kg(-1)) from Yuanyang Lake Nature Preserve among Ilan, Taoyuan, and Hsinchu Counties is the highest among the investigated mountain forest soils. This may be mainly attributed to the fact that Ilan County is located in the northeastern part of Taiwan and faces the northeastern and northern seasonal winds with lots of precipitation annually from mid-autumn through mid-spring next year and is receiving greater amount of fallouts yearly. Due to longer reaction period (>or=3 y) of (137)Cs with soil components, (137)Cs was mainly in the forms bound to oxides and to organic matter in the soil amended with (137)Cs and in the soil contaminated with (137)Cs. On the contrary, due to shorter reaction period (<60 d) of (85)Sr with soil components, (85)Sr was mainly in exchangeable form and partially in the forms bound to carbonates and oxides in the soils amended with (85)Sr.

Randomized double-blind comparison of ketamine-propofol, fentanyl-propofol and propofol-saline on haemodynamics and laryngeal mask airway insertion conditions.

The aim of this prospective, double-blind, randomized, placebo-controlled clinical trial was to investigate whether the administration of ketamine before induction with propofol improves its associated haemodynamic profile and laryngeal mask airway (LMA) insertion conditions. Ninety adult patients were randomly allocated to receive either ketamine 0.5 mg x kg(-1) (n = 30), fentanyl 1 microg x kg(-1) (n = 30) or normal saline (n = 30), before induction of anaesthesia with propofol 2.5 mg x kg(-1). Insertion of the LMA was performed 60s after injection of propofol. Arterial blood pressure and heart rate were measured before induction (baseline), immediately after induction, immediately before LMA insertion, immediately after LMA insertion and every minute for three minutes after LMA insertion. Following LMA insertion, the following six subjective endpoints were graded by a blinded anaesthestist using ordinal scales graded 1 to 3: mouth opening, gagging, swallowing, movement, laryngospasm and ease of insertion. Systolic blood pressure was significantly higher following ketamine than either fentanyl (P = 0.010) or saline (P = 0.0001). The median (interquartile range) summed score describing the overall insertion conditions were similar in the ketamine [median 7.0, interquartile range (6.0-8.0)] and fentanyl groups [median 7.0, interquartile range (6.0-8.0)]. Both appeared significantly better than the saline group [median 8.0, interquartile range (6.75-9.25); P = 0.024]. The incidence of prolonged apnoea (> 120s) was higher in the fentanyl group [23.1% (7/30)] compared with the ketamine [6.3% (2/30)] and saline groups [3.3% (1/30)]. We conclude that the addition of ketamine 0.5 mg x kg(-1) improves haemodynamics when compared to fentanyl 1 microg x kg(-1), with less prolonged apnoea, and is associated with better LMA insertion conditions than placebo (saline).

An evaluation of the modified Airway Management Device.

This is a preliminary report on the use of the modified Airway Management Device in 50 spontaneously breathing patients undergoing elective day care surgery. We were successful in establishing a clear airway in all 50 patients, 46 of these patients had a patient airway on the first attempt. All patients were successfully managed with the Airway Management Device throughout the surgery. Partial airway obstruction during maintenance of anaesthesia occurred in three cases requiring only minor manipulations. Our result showed that the Airway Management Device may be used as an alternative airway management in anaesthesia.

Temporary cardiopulmonary bypass and isolated lung ventilation for tracheal stenosis and reconstruction.

A 27-yr-old lady with a past history of prolonged ventilation presented with worsening respiratory distress caused by tracheal stenosis. She required urgent tracheal resection and reconstruction. Because of the risk of an acute respiratory obstruction, spinal anaesthesia was used to establish cardiopulmonary bypass by cannulating the femoral artery and femoral vein. Adequate gas exchange was possible with full flow rate. Thoracotomy was then carried out to mobilize the left main bronchus. After successfully securing an airway by intubation of the left main bronchus, cardiopulmonary bypass was discontinued and tracheal resection and anastomosis was done under conventional one lung anaesthesia.

The use of modified VBM laryngeal tube compared to Laryngeal Mask Airway during spontaneous ventilation.

We have compared the use of the laryngeal mask airway with the new modified laryngeal tube in a prospective randomized controlled study. Sixty ASA 1 or 2 patients, aged 18 to 65 years, scheduled for elective surgery and breathing spontaneously under general anaesthesia, were studied. After preoxygenation, anaesthesia was induced with fentanyl and propofol. The patients were randomized to receive either a laryngeal mask airway or a laryngeal tube. Anaesthesia was maintained with nitrous oxide, oxygen and isoflurane. We recorded the speed and the ease of insertion, the number of attempts needed to successfully secure the airway and intraoperative complications, such as partial airway obstruction needing airway manipulation. The airway devices were removed with the patients fully awake at the end of surgery. Systolic arterial blood pressure, heart rate and end-tidal CO2 were recorded at various time intervals. Postoperative complications were recorded. We found that the incidence of partial airway obstruction needing intraoperative airway manipulation was higher with the laryngeal tube than with the laryngeal mask airway. We conclude that during spontaneous ventilation the modified laryngeal tube is not as reliable in providing a satisfactory airway and we consider it is not a suitable alternative to the laryngeal mask airway.

Retrospective review of spinal versus epidural anaesthesia for caesarean section in preeclamptic patients.

A 5-year retrospective survey of anaesthesia for caesarean section for mild/moderate and severe preeclampsia was performed, covering the period between 1 January 1996 and 31 December 2000. One hundred and twenty-one cases of non-labouring preeclamptic patients receiving spinal or epidural anaesthesia for caesarean section were included for analysis. Comparisons were made of the lowest blood pressures recorded before induction of anaesthesia, during the period from induction to delivery and the period from delivery to the end of operation. The decreases in blood pressure were similar after spinal and epidural anaesthesia. The use of intravenous fluids and ephedrine were also comparable in the two anaesthetic groups. There was no difference in maternal or neonatal outcome. Our result supports the use of spinal anaesthesia in preeclamptic women.

A comparative study of sevoflurane sedation with nitrous oxide sedation for dental surgery.

This study compares the use of inhalation sedation using sevoflurane (group S) with inhalation sedation using nitrous oxide (group N) in patients undergoing bilateral extraction of third molar teeth under local anaesthesia. The study was designed as a cross-over study. Seventeen ASA I, day surgery patients were studied. Patients were randomly allocated to receive either 8 l/min 50% nitrous oxide in oxygen (group N) or same flow of 1% sevoflurane (group S) for the first procedure. Each patient then had the alternate method of sedation for the second procedure. There were no significant differences between the methods in patient co-operation and surgeon's satisfaction with sedation. Psychomotor tests were comparable in both groups. The patients were significantly more sedated in the group S compared to group N (P=0.004). Significantly more patients complained of an unpleasant odour group S (P<0.01) but none withdrew from the study for this reason. No adverse cardiorespiratory effects resulted from sevoflurane or nitrous oxide sedation. Both methods gave good amnesia during the procedure. There was high acceptance of both methods and the patients rated the technique as equally satisfactory. We conclude that inhalation sedation with sevoflurane is a suitable alternative method to nitrous oxide sedation.

Trends in obstetric anaesthesia and analgesia over a ten year period in the University Malaya Medical Centre, Kuala Lumpur.

Available data for obstetric care in the University Malaya Medical Centre, Kuala Lumpur from 1987 to 1999 were reviewed. Despite incomplete data, we were able to determine fairly well the practice of obstetric anaesthesia and analgesia in the unit, and the changes over the years. There was a decline in the use of general anaesthesia for both elective and emergency caesarean sections from 41.3% and 69.4% respectively in 1995 to 21.6% and 26.9% respectively in 1999. By 1999, regional anaesthesia had become the most common method of anaesthesia administered in both elective (14.3% epidural and 63.5% spinal) and emergency (30.2% epidural and 42.6% spinal) caesarean sections. The percentage of patients delivering vaginally who received epidural analgesia appeared to have stabilised at about 8 to 9% in the last few years, with a gradual decline in the total instrumental delivery rate from a high of about 12% to the pre-epidural rate of 7%.

The effect of prophylactic metaraminol on systemic hypotension caused by induction of anaesthesia with propofol in patients over 55 years old.

We conducted a double-blind, randomised, placebo-controlled study evaluating the efficacy of prophylactic metaraminol for preventing propofol-induced hypotension. Thirty patients aged 55-75 years undergoing general anaesthesia were randomly allocated to receive either metaraminol 0.5 mg or saline before administration of fentanyl 1 microg.kg(-1) and propofol 2 mg.kg(-1). Induction of anaesthesia was associated with a decrease in mean and systolic arterial pressure in both groups (p = 0.0001). However, there was no significant difference between the two groups. These results show that prophylactic use of metaraminol 0.5 mg does not prevent the decrease in blood pressure following fentanyl and propofol induction in older patients.

Fatal hepatorenal failure associated with hydrazine sulfate.

BACKGROUND: The Internet has revolutionized the manner in which patients obtain information about health care. This technology has also allowed patients to obtain directly both prescription and nonprescription therapies. OBJECTIVE: To report a case of fulminant hepatorenal failure associated with the use of hydrazine sulfate, an unregulated alternative remedy for cancer marketed on the Internet. DESIGN: Case report. SETTING: Academic medical center. PATIENT: A 55-year-old man with maxillary sinus cancer. INTERVENTION: Self-medication with hydrazine sulfate. MEASUREMENTS: Serum liver and renal function tests; histologic evaluation of liver and kidney tissue. RESULTS: The patient developed hepatic encephalopathy, renal failure, and profound coagulopathy. He died after severe gastrointestinal hemorrhage developed. Autopsy revealed autolysis of the kidneys and submassive bridging necrosis of the liver. CONCLUSION: Fatal hepatorenal failure may occur after the use of hydrazine sulfate. This fatal complication must be considered in anyone taking or contemplating the use of hydrazine sulfate.