Gerard W. Ostheimer Lecture 2006: What’s New in Obstetric Anaesthesia? Contributions from the 2005 literature

The Gerard W. Ostheimer lecture is given every year at the annual meeting of the Society for Obstetric Anesthesia and Perinatology by an obstetric anaesthesiologist who has reviewed the scientific literature for the previous calendar year. This article is based on the 2006 Ostheimer lecture and reviews three areas of interest in neonatology: resuscitation of the newborn, neonatal encephalopathy and the influence of epidural analgesia on breastfeeding.

An outbreak of Aspergillus meningitis following spinal anaesthesia for caesarean section in Sri Lanka: a post-tsunami effect?

An outbreak of Aspergillus fumigatus meningitis occurred in 5 women following spinal anaesthesia, performed between 21 June and 17 July 2005 for caesarean section, in Colombo, Sri Lanka. The patients' median age was 27 years. Different teams in 2 maternity hospitals gave spinal anaesthesia. Mean incubation period was 11.2 days. Fever, headache and nuchal rigidity were common presentations. Remittent fever continued despite broad-spectrum intravenous antibiotics. Papilloedema, lateral rectus palsy, cerebral infarction and haemorrhage developed later. Three patients died. Cerebrospinal fluid pleocytosis with low glucose yielded negative PCR for fungi. Fungal cultures subsequently grew Aspergillus fumigatus. A post-mortem of the first patient confirmed Aspergillus meningitis, followed by treatment with amphotericin B and voriconazole, that saved the lives of others. Visual and hearing impairment in one and complete recovery in the other were observed a year after treatment. Examination of unused plastic syringes, needles, cannulae, and ampoules of anaesthetic agents confirmed that 43 syringes from three different manufactures were contaminated with Aspergillus fumigatus. The stores for drugs and devices of the Ministry of Health were examined and found to be full of tsunami donations, while regular procurements of the Ministry were kept in a poorly maintained humid warehouse. Inadequate space for tsunami donations was identified as the most plausible explanation for sub-optimal storage. Withdrawal and incineration of all unused syringes controlled the outbreak. The survival of those aggressively treated for Aspergillus meningitis suggests in hindsight that the availability of diagnostic tests and specific treatment, and early recognition of the outbreak could have saved the lives of victims who died. Early life-threatening side-effects and permanent long term sequelae of antifungal medication stress the need to be cautious with empirical treatment in immuno-competent low-risk individuals.

Paclitaxel induced apoptosis in breast cancer cells requires cell cycle transit but not Cdc2 activity

PURPOSE

Paclitaxel (PTX) is a widely used chemotherapy agent and may cause cell death by apoptosis subsequent to microtubule (MT) disruption. In this paper, we have investigated whether cell cycle transit and or Cdc2 (Cdk1) activity is required for the apoptosis induced by PTX.

METHODS

Cell cycle was analyzed by flow cytometry, Cdc2 was assayed bio chemically. Cdc2 activity was decreased by siRNA and dominant negative (dn) Cdc2 expression. Cells were arrested by chemical or biological inhibitors in a G1 or S phase. Apoptosis was measured by DNA fragmentation and examination of nuclei by microscopy. JNK and AKT activations were assessed as well.

RESULTS

Cell cycle inhibition was highly effective in decreasing PTX induced apoptosis. MT morphology was not altered by these inhibitors. PTX induced JNK activity or AKT mediated BAD phosphorylation was unaffected by cell cycle inhibitors. Abrogation of Cdc 2 activity was without effect on PTX induced apoptosis.

CONCLUSIONS

While cell cycle transit is required for PTX induced apoptosis; Cdc2 activity is not required.

Methods of repair for obstetric anal sphincter injury

BACKGROUND

Anal sphincter injury during childbirth - obstetric anal sphincter injuries (OASIS) - is associated with significant maternal morbidity including perineal pain, dyspareunia and anal incontinence. Anal incontinence affects women psychologically and physically. Many do not seek medical attention because of embarrassment. The two recognised methods for the repair of damaged external anal sphincter (EAS): are end-to-end (approximation) repair and overlap repair.

OBJECTIVES

To compare the effectiveness of overlap repair versus end-to-end repair following OASIS in reducing subsequent anal incontinence, perineal pain, dyspareunia and improving quality of life.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 January 2006), MEDLINE (January 1966 to 31 January 2006), EMBASE (January 1974 to 31 January 2006), SciSearch (January 1974 to 31 January 2006) and conference proceedings of obstetrics and gynaecology, surgery and coloproctology.

SELECTION CRITERIA

Randomised controlled trials comparing different techniques of immediate primary repair of EAS following OASIS.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed independently by all authors.

MAIN RESULTS

Three eligible trials, of grade A quality, involving 279 women, were included. There was considerable heterogeneity in the outcome measures, time points and reported results. Meta-analyses showed that there was no statistically significant difference in perineal pain (relative risk (RR) 0.08, 95% confidence interval (CI) 0.00 to 1.45, one trial, 52 women), dyspareunia (RR 0.62, 95% CI 0.11 to 3.39, one trial, 52 women), flatus incontinence (RR 0.93, 95% CI 0.26 to 3.31, one trial, 52 women) and faecal incontinence (RR 0.07, 95% CI 0.00 to 1.21, one trial, 52 women) between the two repair techniques at 12 months but showed a statistically significantly lower incidence in faecal urgency (RR 0.12, 95% CI 0.02 to 0.86, one trial, 52 women) and lower anal incontinence score (weighted mean difference -1.70, 95% CI -3.03 to -0.37) in the overlap group. Overlap technique was also associated with a statistically significant lower risk of deterioration of anal incontinence symptoms over 12 months (RR 0.26, 95% CI 0.09 to 0.79, one trial, 41 women). There was no significant difference in quality of life.

AUTHORS' CONCLUSIONS

The limited data available show that compared to immediate primary end-to-end repair of OASIS, early primary overlap repair appears to be associated with lower risks for faecal urgency and anal incontinence symptoms. As the experience of the surgeon is not addressed in the three studies reviewed, it woudl be inappropriate to recommend one type of repair in favour of another.

The effects of biocides (antiseptics and disinfectants) on the endospores ofRhinosporidium seeberi

No data exists on the activity of biocides (antiseptics and disinfectants) on Rhinosporidium seeberi that causes rhinosporidiosis in humans and animals. On account of the inability to culture R. seeberi, in vitro, dyes were used to assess the morphological integrity and viability of biocide-treated endospores that are considered to be the infective stage of this pathogen. Evan's Blue (EvB) identifies the morphological integrity of the endospores while MTT (3-[4, 5-dimethylthiazol-2yl]-2, 5-diphenyl tetrazolium bromide) identifies metabolic activity through its reduction by cellular dehydrogenases to microscopically visible deposits of insoluble formazan. MTT-negativity has earlier been shown to correlate with absence of growth of yeast and mycelial fungi in culture and could thus indicate the loss of viability of MTT-negative rhinosporidial endospores. Hydrogen peroxide, glutaraldehyde, chloroxylenol, chlorhexidine, cetrimide, thimerosal, 70% ethanol, iodine in 70% ethanol, 10% formalin, povidone-iodine, sodium azide and silver nitrate were tested on freshly-harvested endospores and all biocides caused metabolic inactivation with or without altered structural integrity as shown by absence of MTT-staining after 3, 24 or 36 hour after exposure, while EvB stained only the endospores treated with sodium azide, ethanol, thimerosal, chloroxylenol, glutaraldehyde and hydrogen peroxide. With clinically useful biocides - chlorhexidine, cetrimide-chlorhexidine, 70% ethanol, povidone-iodine and silver nitrate, a total period of exposure of endospores to the biocide, for seven minutes, produced metabolic inactivation of the endospores. Anti-rhinosporidial antiseptics that could be used in surgery on rhinosporidial patients include povidone-iodine in nasal packs for nasal and naso-pharyngeal surgery, chlorhexidine and cetrimide-chlorhexidine on the skin, while povidone-iodine and silver nitrate could have application in ocular rhinosporidiosis.

Computed tomography pseudofractures of the mid face and skull base

Thin-section multislice CT delineates numerous normal skull-base and mid-facial bony discontinuities. These represent sutures, fissures and neurovascular foramina or channels, and should be differentiated from fractures. This pictorial review describes and illustrates the characteristic location and multiplanar CT appearances of these structures. Their clinical significance in terms of pathological processes and surgical planning are discussed.

The angiotensin IV/AT4 receptor

The angiotensin AT(4) receptor was originally defined as the specific, high-affinity binding site for the hexapeptide angiotensin IV (Ang IV). Subsequently, the peptide LVV-hemorphin 7 was also demonstrated to be a bioactive ligand of the AT(4) receptor. Central administration of Ang IV, its analogues or LVV-hemorphin 7 markedly enhance learning and memory in normal rodents and reverse memory deficits observed in animal models of amnesia. The AT(4) receptor has a broad distribution and is found in a range of tissues, including the adrenal gland, kidney, lung and heart. In the kidney Ang IV increases renal cortical blood flow and decreases Na(+) transport in isolated renal proximal tubules. The AT(4) receptor has recently been identified as the transmembrane enzyme, insulin-regulated membrane aminopeptidase (IRAP). IRAP is a type II integral membrane spanning protein belonging to the M1 family of aminopeptidases and is predominantly found in GLUT4 vesicles in insulin-responsive cells. Three hypotheses for the memory-potentiating effects of the AT(4) receptor/IRAP ligands, Ang IV and LVV-hemorphin 7, are proposed: (i) acting as potent inhibitors of IRAP, they may prolong the action of endogenous promnestic peptides; (ii) they may modulate glucose uptake by modulating trafficking of GLUT4; (iii) IRAP may act as a receptor, transducing the signal initiated by ligand binding to its C-terminal domain to the intracellular domain that interacts with several cytoplasmic proteins.

Regulation of lipoprotein trafficking in the kidney: role of inflammatory mediators and transcription factors

Inflammation and dyslipidaemia both play important roles in the development of glomerular atherosclerosis in renal diseases. We have demonstrated that inflammatory mediators induced Scr (scavenger receptor) expression and the formation of foam cells, and that AP-1 (activator protein 1)/ets were necessary transcriptional factors for Scr induction in HMCs (human kidney mesangial cells). Most cells are protected from excessive native LDL (low-density lipoprotein) accumulation by tight feedback regulation of the LDLr (LDL receptor). However, we observed that HMCs formed foam cells via the LDLr pathway when incubated with IL-1β (interleukin-1β; 5 ng/ml) and unmodified LDL (200 μg/ml), suggesting that inflammatory mediators may disrupt the cholesterol-mediated feedback regulation. This feedback involves cholesterol-mediated down-regulation of LDLr controlled by SCAP [SREBP (sterol responsive element-binding protein) cleavage-activating protein]. We have also demonstrated that both tumour necrosis factor α and IL-1β increased nuclear SREBP-1 levels by increasing SCAP mRNA expression, even in the presence of a high concentration of LDL. Since intracellular lipid content is governed by both influx and efflux mechanisms, we set out to examine the impact of inflammatory cytokines on cholesterol efflux, a process mediated by the protein ABCA1 (ATP binding cassette A1). IL-1β inhibited [3H]cholesterol efflux from HMCs by inhibition of the peroxisome-proliferator-activated receptor/LXR (liver X receptor)/ABCA1 pathway. Taken together, our results suggest that inflammatory mediators increase lipid accumulation in HMCs not only by promoting increased lipoprotein uptake by Scr and LDLr, but also by inhibiting ABCA1-mediated cholesterol efflux to high-density lipoprotein.

A study of the investigation of death (coroner system) in Sri Lanka

Sri Lanka (Ceylon) inherited the 'coroner system' of investigating death in the early nineteenth century. Unlike in England and Wales, the coroner system in Sri Lanka did not change much in the last century. This study, the first of its kind, was performed for a period of three months in 1995 to analyse the causes and circumstances of deaths reported for inquest, and the number of autopsies performed. Of the 868 cases reported to the Inquirer, the circumstances were not determined in 94 cases at the initial inquest proceedings. Of the other 774 cases, 454 (58.7%) were natural deaths. Autopsies were performed on 44.5% of natural deaths, 58.2% of accidental deaths, 96% of road traffic accidents, 44.9% of suicides and 81.6% of homicides. Coronary heart disease was the leading cause of natural death (33.9%). Head injuries were responsible for 31.8% of accidental deaths while burns accounted for 24.5% of accidental deaths and 46.3% of suicides. There were 38 cases (4.9%) of homicide of which autopsies were performed in 31. There is an urgent need to reform the century-old laws relating to inquest procedures in the country.

Protein kinase-dependent phosphorylation of the Menkes copper P-type ATPase

The Menkes copper-translocating P-type ATPase (ATP7A; MNK) is a key regulator of copper homeostasis in humans. It has a dual role in supplying copper to essential cuproenzymes in the trans-Golgi network (TGN) and effluxing copper from the cell. These functions are achieved through copper-regulated trafficking of MNK between the TGN and the plasma membrane. However, the exact mechanism(s) which regulate the localisation and biochemical functions of MNK are still unknown. Here we investigated copper-dependent phosphorylation of MNK by a putative protein kinase(s). We found that in the presence of elevated copper there was a substantial increase in phosphorylation of the wild-type MNK in vivo. The majority of copper-dependent phosphorylation was on serine residues in two phosphopeptides. In contrast, there was no up-regulation of phosphorylation of a non-trafficking MNK mutant with mutated cytosolic copper-binding sites. Our findings suggest a potentially important role of kinase-dependent phosphorylation in the regulation of function of the MNK protein.

Cell-mediated immune responses (CMIR) in human rhinosporidiosis

Cell mediated immune responses (CMIR) to Rhinosporidium seeberi in human patients with rhinosporidiosis have been studied. With immuno-histochemistry, the cell infiltration patterns in rhinosporidial tissues from 7 patients were similar. The mixed cell infiltrate consisted of many plasma cells, fewer CD68+ macrophages, a population of CD3+ T lymphocytes, and CD56/57+ NK lymphocytes which were positive for CD3 as well. CD4+ T helper cells were scarce. CD8+ suppressor/cytotoxic-cytolytic cells were numerous. Most of the CD8+ cells were TIA1+ and therefore of the cytotoxic subtype. CD8+ T cells were not sub-typed according to their cytokine profile; 1L2, IFN-gamma (Tcl); IL4, ILS (Tc2). In lympho-proliferative response (LPR) assays in vitro, lymphocytes from rhinosporidial patients showed stimulatory responses to Con A but lymphocytes from some patients showed significantly diminished responses to rhinosporidial extracts as compared with unstimulated cells or cells stimulated by Con A, indicating suppressor immune responses in rhinosporidiosis. The overall stimulatory responses with Con A suggested that the rhinosporidial lymphocytes were not non-specifically anergic although comparisons of depressed LPR of rhinosporidial lymphocytes from individual patients, to rhinosporidial antigen with those to Con A, did not reveal a clear indication as to whether the depression was antigen specific or non-specific. The intensity of depression of the LPR in rhinosporidial patients bore no relation to the site, duration, or the number of lesions or whether the disease was localized or disseminated. Rhinosporidial extracts showed stimulatory activity on normal control lymphocytes, perhaps indicating mitogenic activity. These results indicate that CMIR develops in human rhinosporidiosis, while suppressed responses are also induced.

Disposition of inhaled mercury vapor in pregnant rats: maternal toxicity and effects on developmental outcome

The disposition and toxicity of inhaled elemental mercury (Hg0) vapor for pregnant Long-Evans rats, and potential adverse effects on reproductive outcome were investigated. Rats were exposed to 0, 1, 2, 4, or 8 mg Hg0/m(3) for 2 h/day from gestation day (GD) 6 through GD 15. Maternal toxicity occurred primarily in rats exposed to 4 and 8 mg/m(3) and was manifested as a concentration-related decrease in body weight gain and mild nephrotoxicity. Control rats gained about 13% of their initial body weight during the 10-day exposure. Rats exposed to 4 mg/m(3) Hg0 gained about 7% less than controls, and rats exposed to 8 mg/m(3) Hg0 lost about 17% of their initial body weight during the 10-day exposure period. Maternal kidney weights were significantly increased in the 4 and 8 mg/m(3) concentration groups, and urinalysis revealed increased levels of protein and alkaline phosphatase activity in urine of all Hg0-exposed rats. Dams exposed to 8 mg/m(3) were euthanized in moribund condition on postnatal day (PND) 1. There was no histopathological evidence of toxicity in maternal lung, liver, or kidney of exposed rats at GD 6, GD 15, or PND 1. The incidence of resorptions was significantly increased, litter size and PND 1 neonatal body weights were significantly decreased only in the 8-mg/m(3) group. Total Hg concentrations in maternal tissues increased with increasing number of exposure days and concentration. In general, approximately 70% of Hg was eliminated from maternal tissues during the week following the last exposure (GD 15 to PND 1). Elimination of Hg from maternal brain and kidney was slower than in other tissues, possibly due to higher levels of metallothionein. Total Hg concentrations in fetal tissues increased with increasing number of exposure days and concentration, demonstrating that a significant amount of Hg crossed the placenta. One week after the last exposure, significant amounts of Hg were still present in brain, liver, and kidney of PND 1 neonates. Metallothionein levels in neonatal tissues were not significantly increased by exposure to 4 mg/m(3) Hg0. The total amount of Hg in neonatal brain (ng/brain) continued to increase after termination of inhalation exposure, suggesting a redistribution of Hg from the dam to neonatal brain. These data demonstrate that inhaled Hg0 vapor is distributed to all maternal and fetal tissues in a dose-dependent manner. Adverse effects of Hg on developmental outcome occurred only at a concentration that caused maternal toxicity.

Primary endodermal sinus (yolk sac) tumour of the liver

Primary endodermal sinus tumour of the liver is an extremely rare neoplasm. A 37-year-old man presented with a mass in the left lobe of the liver and a raised serum alpha-fetoprotein concentration. A left hepatic lobectomy was performed. Histological examination revealed an endodermal sinus tumour of the liver. There was no evidence of an extrahepatic primary source.

Primary endodermal sinus (yolk sac) tumour of the liver

Primary endodermal sinus tumour of the liver is an extremely rare neoplasm. A 37-year-old man presented with a mass in the left lobe of the liver and a raised serum alpha-fetoprotein concentration. A left hepatic lobectomy was performed. Histological examination revealed an endodermal sinus tumour of the liver. There was no evidence of an extrahepatic primary source.

Intermittent oral iron supplementation during pregnancy

RATIONALE

It has been suggested that in pregnant women weekly iron supplements are as effective as daily supplements in preventing iron deficiency anaemia (IDA).

OBJECTIVE

To compare the effectiveness of prophylactic antenatal oral iron supplements given weekly, thrice weekly and daily in preventing IDA in pregnancy.

DESIGN

A randomised control trial.

SETTING

University antenatal clinic, (UANC) Galle.

SUBJECTS AND METHOD

An oral iron supplement containing 100 mg of elemental iron was randomly given weekly (n = 26) thrice weekly (n = 35) and daily (n = 31) to 92 women who were 14 to 24 weeks pregnant. Haemoglobin (Hb), serum ferritin (SF) and haematocrit (Hct) were assessed before and after 12 to 20 weeks of supplementation and a logistic regression analysis carried out.

RESULTS

The risk of developing anaemia was significantly higher in the weekly (odds ratio 15, 95% CI 1.4-165.6, p < 0.03) and possibly higher in the thrice weekly (odds ratio 3, 95% CI 0.3-30.3, p = 0.3) groups. The risk of developing iron deficiency (SF < 12 micrograms/l) was also significantly higher in the weekly (odds ratio 18, 95% CI 2.8-115.5, p < 0.003) and thrice weekly (odds ratio 10, 95% CI 1.6-64.8, p < 0.02) groups.

CONCLUSION

Prophylactic oral iron supplements when given intermittently were not effective in preventing iron deficiency anaemia in pregnancy.

Minimum local analgesic dose of intrathecal bupivacaine in labor and the effect of intrathecal fentanyl

BACKGROUND

Combining bupivacaine with fentanyl for intrathecal analgesia in labor is well recognized, but dosages commonly used are arbitrarily chosen and may be excessive. This study aimed to determine the median effective dose (ED50) of intrathecal bupivacaine, defined as the minimum local analgesic dose (MLAD), and then use this to assess the effect of different doses of fentanyl.

METHODS

In this double-blind, randomized, prospective study, 124 parturients receiving combined spinal epidural analgesia at 2-6-cm cervical dilatation were allocated to one of four groups to receive bupivacaine alone or with 5, 15, or 25 microg fentanyl, using the technique of up-down sequential allocation. Analgesic effectiveness was assessed using 100-mm visual analog pain scores, with less than or equal to 10 mm within 15 min defined as effective. MLAD was calculated using the formula of Dixon and Massey. Pruritus and duration of spinal analgesia were also recorded.

RESULTS

Minimum local analgesic dose of intrathecal bupivacaine was 1.99 mg (95% confidence interval, 1.71, 2.27). There were similar significant reductions in MLAD (P < 0.001) for all bupivacaine-fentanyl groups compared with bupivacaine control. There was a dose-dependent increase in both pruritus and duration of spinal analgesia with increasing fentanyl (P < 0.0001).

CONCLUSION

Under the conditions of this study, the addition of intrathecal fentanyl 5 microg offers a similar significant bupivacaine dose-sparing effect as 15 and 25 microg. Analgesia in the first stage of labor can be achieved using lower doses of fentanyl, resulting in less pruritus but with a shortening of duration of action.

Mercury vapor and female reproductive toxicity

Epidemiological studies finding menstrual cycle abnormalities among women occupationally exposed to Hg degrees prompted us to investigate the mechanisms of reproductive toxicity of Hg degrees in the female rat. Nose-only Hg degrees vapor inhalation exposures were conducted on regularly cycling rats 80-90 days of age in dose-response and acute time-course studies, which have previously proven useful as a model to identify ovarian toxicants. Vaginal smears were evaluated daily and serum hormone levels were correlated with cycle and with ovarian morphology at necropsy. Exposure concentration-related effects of Hg degrees were evaluated by exposing rats to 0, 1, 2, or 4 mg/m3 Hg degrees vapor 2 h/day for 11 consecutive days. Tissue Hg levels correlated with exposure concentration and duration. Exposure of rats to 4 mg/m3 (but not 1 or 2 mg/m3) Hg vapor for 11 days resulted in significant decreases in body weights relative to controls. Estrous cycles were slightly prolonged in the 2 and 4 mg/m3 dose groups, and serum estradiol and progesterone levels were significantly different in the 4 mg/m3 group compared to controls. The alterations in cycle and hormones at the 4 mg/m3 exposure concentration were attributed to body weight loss and generalized toxicity. In the time-course study, rats were exposed to 2 mg/m3 Hg degrees or air beginning in metestrus and evaluated daily for 8 days. A lengthening of the cycle was detected and morphological changes were observed in the corpora lutea (CL) after exposure for 6 days. To determine if changes in the CL and cyclicity correlated with a functional defect, rats were exposed to Hg degrees vapor and evaluated for pregnancy outcome. There were no significant effects on pregnancy rate or numbers of implantation sites when rats were exposed to 1 or 2 mg/m3 Hg degrees for 8 days prior to breeding, or when exposed for 8 days after breeding. These studies indicate that exposure to Hg degrees vapor altered estrous cyclicity, but had no significant effect on ovulation, implantation, or maintenance of first pregnancy during exposure of short duration in female rats.

Inferring the trajectory of genetic variance in the course of artificial selection

A method is proposed to infer genetic parameters within a cohort, using data from all individuals in an experiment. An application is the study of changes in additive genetic variance over generations, employing data from all generations. Inferences about the genetic variance in a given generation are based on its marginal posterior distribution, estimated via Markov chain Monte Carlo methods. As defined, the additive genetic variance within the group is directly related to the amount of selection response to be expected if parents are chosen within the group. Results from a simulated selection experiment are used to illustrate properties of the method. Four sets of data are analysed: directional selection with and without environmental trend, and random selection, with and without environmental trend. In all cases, posterior credibility intervals of size 95% assign relatively high density to values of the additive genetic variance and heritability in the neighbourhood of the true values. Properties and generalizations of the method are discussed.

Evaluation of a spinal needle locking device for use with the combined spinal epidural technique

Success of the 'needle-through-needle' technique for combined spinal epidural analgesia requires the immobilisation of the spinal needle during intrathecal injection. A device that achieves this was evaluated in 200 labouring women, randomly allocated to receive a combined spinal epidural using the CSEcure(R) (SIMS Portex, UK) locking needle or a conventional, non-locking technique. Data collection included the incidence of dural click as the spinal needle penetrated the dura mater, presence of cerebrospinal fluid in the spinal needle hub and the number of technical failures with the spinal component. Successful dural punctures with the spinal needle were similar for locking and non-locking needles (99.0 vs. 98.0%; p = 0.55), despite a small but significant reduction in dural click with the locking needle compared with the non-locking technique (97. 0 vs. 84.7%; p < 0.01). Although not statistically significant, there was a higher number of technical failures, mainly due to spinal needle movement, in the non-locking group (9.1 vs. 3.1%; p = 0.08). The locking needle device may be a useful alternative to conventional methods for combined spinal epidural analgesia.

Anti-inflammatory pre-treatment and the resultant effects of interleukin-10: adjuncts to multi-therapeutical strategies

With the advent of off-pump coronary bypass surgery, there is increasing demand for research in attenuating the deleterious effects of cardiopulmonary bypass (CPB). An improved understanding of the systemic inflammatory response syndrome (SIRS) has distinguished which areas of components have the most adverse effects and which are, in fact, anti-inflammatory. This classification of inflammatory components allows strategic treatment for those likely to cause the most clinically significant 'effect', suitably termed 'effectors'. This article will identify current methods in treating 'effectors', as well as those components having anti-inflammatory effects. This article selectively features certain inflammatory components by: (1) grouping them as being 'mediators' or 'effectors'; (2) relating them to interleukin-10 (IL-10) and treatments potentiating anti-inflammatory effects; (3) summarizing their mechanisms of action; (4) recognizing the time periods during bypass exhibiting peak levels; and (5) investigating current treatment. methods and identifying their significance to 'effectors'. A literature search in MEDLINE was performed, featuring articles of the English-language within the past 5 years. Because of the characteristic of having interlinked multi-component cascades, it is evident that treating SIRS with a one-dimensional method would be inadequate. This article not only confirms the importance of a multi-factorial therapeutic approach, but also targets the inflammatory components having the highest potential for causing direct tissue damage, known as 'effectors'. In addition, previous studies have found IL-10 to have 'regulatory effects' during periods of excessive pro-inflammatory stimuli. These findings may arouse new ideas in exploring the area of anti-inflammatory cytokines. In fact, future treatments may suggest a new classification featuring 'mediators', 'effectors', and 'regulators'.

Internal carotid-artery response to 5% carbon dioxide in women with polycystic ovaries

Although polycystic ovary syndrome is associated with hypertension, hyperlipidaemia, and insulin resistance, mortality from cerebrovascular disease is not increased. We previously reported lower downstream resistance in the internal carotid artery in women with polycystic ovary syndrome. This study was designed to assess vascular reactivity by measuring the response to inhalation of 5% carbon dioxide. We studied 34 young women with polycystic ovary syndrome, 15 with symptomless polycystic ovaries, and 18 controls.

Pain perception with pH buffered peribulbar anaesthesia: a pilot study

AIMS

To determine the relation between pH of anaesthetic solutions and patient perception of pain with peribulbar injection of local anaesthesia.

METHODS

This prospective randomised controlled double blind pilot study involved 60 consecutive patients who received a peribulbar block with either a standard acidic local anaesthetic of 5 ml 2% lignocaine and 5 ml of 0.5% bupivacaine (solution A), or an alkalinised solution composed of the same anaesthetic agents but with a pH of 7.44 (solution B). Before surgery patients were asked to grade the pain of both the preoperative dilating drops and the peribulbar injection using a visual analogue scale.

RESULTS

The mean pain scores were similar in the two treatment groups-slightly higher (4.97) in group B who received the buffered solution, compared with group A (4.84) who received the plain solution. The small difference (-0.13, 95% confidence limits -1.6 and +1.3) was not significant. There was, however, a highly significant association between pain threshold ("drop pain") and injection pain levels (p<0.0001).

CONCLUSION

This study showed no difference in the reduction in the pain experienced by patients undergoing peribulbar anaesthesia with pH buffered local anaesthetic. The study suggests the importance of "pain threshold" as a confounder and also showed the considerable pain felt by some patients on instillation of the preoperative dilating drops.

Chemical stability of bupivacaine, lidocaine and epinephrine in pH-adjusted solutions

Epinephrine and sodium bicarbonate may be added to local anaesthetic solutions in order to reduce the onset time and enhance the quality of epidural anaesthesia for Caesarean section. Such mixtures are sometimes prepared several hours in advance for subsequent use in emergency Caesarean section through a pre-existing epidural catheter. To evaluate this practice, we studied the chemical stability in solution over 24 h of nine epidural mixtures consisting of different combinations of bupivacaine, lidocaine, epinephrine and sodium bicarbonate. In mixtures alkalinised with sodium bicarbonate, epinephrine concentrations decreased significantly over 24 h (p<0.0001), whereas those in nonalkalinised mixtures did not change with time. Bupivacaine and lidocaine concentrations in all mixtures did not decrease over time regardless of alkalinisation. We do not recommend adding epinephrine to alkalinised epidural solutions that are to be stored for a prolonged period before clinical use.

Internal carotid artery haemodynamics in women with polycystic ovaries

Although polycystic ovarian syndrome (PCOS) is associated with risk factors for cerebrovascular disease, the available evidence does not demonstrate increased stroke mortality, and it has been suggested that some protective mechanisms must be operating in these women. Haemodynamic changes have been demonstrated in the pelvic vessels and aorta in this syndrome, but there have been no studies of the cerebral circulation. Since insulin resistance is a central feature of PCOS, it is of interest that cerebral blood flow may be altered in diabetic subjects. The present study was designed to assess internal carotid artery haemodynamics in women with PCOS, asymptomatic women with polycystic ovaries (PCO women) and healthy controls. Mean internal carotid pulsatility index, measured using pulsed Doppler ultrasound under standardized conditions, was significantly lower in 35 PCOS and 15 PCO women than in the 18 controls. This was also shown on multiple regression analyses. Peak systolic velocity did not differ between groups. In view of the difficulty of interpreting pulsatility index in low-impedance vascular beds, the 'back' pressure was calculated and found to be lower in women with polycystic ovaries. This is the first demonstration of lower pulsatility index and back pressure (suggestive of reduced vascular tone) in the cerebral circulation of these women, independent of blood pressure, insulin resistance and other endocrine or metabolic factors. Changes in internal carotid haemodynamics may offset the risk of cerebrovascular disease commonly associated with polycystic ovaries.

Postpartum headache after epidural blood patch: investigation and diagnosis

Use of an epidural blood patch to treat spinal headache after accidental dural puncture is well recognized. The high success rate associated with this practice has been questioned and it is not uncommon for patients to suffer recurring headaches after a supposedly successful blood patch. We describe a patient in labour who suffered accidental dural puncture, and whose headache was treated twice with an epidural blood patch. Despite this, the headache persisted. The case highlights the difficulty in the diagnosis of headache in the postnatal period in patients who have had regional analgesia and the importance of considering an alternative pathology, even if epidural blood patching has been successful. In this case, a diagnosis of cortical vein thrombosis was made. The incidence, presentation, aetiology and treatment of this rare condition is described.

Homicidal poisoning with glibenclamide

Homicidal poisoning is rare in Sri Lanka although suicidal poisoning, especially with pesticides, is a grave health problem. Clinical and medicolegal findings and the subsequent court proceedings of two cases of homicide due to induced hypoglycaemia with an anti-diabetic drug are presented. The drug used was glibenclamide. Findings emphasize the importance of toxicological analysis and extensive police investigations when the clinical diagnosis and the cause of death are in doubt.

Development of the human dispermic embryo

In a recent CD-ROM, we portrayed the microstructure of the pre-implantation human embryo (Sathananthan et al., 1999), which was a multimedia production with computer colour-enhanced electron micrographs of mainly monospermic embryos. This disk portrays light and electron micrographs of over 250 tripronuclear (3PN), dispermic, human embryos during pre-implantation development, viewed in thick and thin Araldite sections, as well as appearances of whole embryos flat embedded in Araldite blocks visualized with the light microscope. The 100 figures were computerized (IBM TIFF format), edited and labelled using Adobe Photoshop 5. Some of the figures were coloured on computer. The early development of 3PN embryos overtly resembles that of normal embryos but there are important differences in their microstructure which are portrayed in this presentation. This is a multicentric study involving researchers from four IVF centres.

Analysis of mercury in hair of EPA region V population

A scoping study, the National Human Exposure Assessment Survey (NHEXAS) was conducted in EPA Region V from July 1995 to May 1997. This probability-based population study provided an opportunity to examine the mercury levels in 182 participants who provided hair samples. A sensitive analytical procedure based on atomic fluorescence spectrometry was developed and evaluated for the analysis of Hg in approximately 5 mg of human hair. The correlation coefficient (r), the precision, and bias were 0.9983, < or = 1.6%, and < or = 8%, respectively, for standard curves in the hair matrix. The method detection limit (MDL), recovery of Hg in a certified sample (NIES-13), precision (% RSD) for duplicate extract analysis, and precision for duplicate sample analysis averaged 12 ppb (range 4 to 22 ppb), 100 +/- 3% (N=27), 4.6 +/- 2.8 (N=18), and 12.5 +/- 7.4 (N=17), respectively, over the 7 to 8 months of sample analysis. The low MDL yielded 95% of the samples with measurable values, permitting the entire distribution of Hg levels to be characterized. Comparison of annualized Hg distribution in hair with and without background correction revealed a negligible bias on the distribution (1.47% at the 90th percentile). Also, a comparison of the unweighted and nonannualized weighted Hg levels throughout the percentile distribution indicated a small deviation in the upper tail (95th percentile) and is attributable to the small sample size (N=182). The mean, median, and maximum of the annualized Hg levels in hair were 287, 204, and 3505 ppb, respectively. The 75th percentiles were 335 and 368 ppb for the weighted annualized and unweighted distributions, respectively. The percent of individuals in three age categories (0-24, 25-49, and 50 years and older) who exceeded the 75th percentile showed a linear increase with age. Males (N=81) had 10% and 20% lower mean levels than females (N=101) for unweighted and annualized weighted Hg data, respectively. The application of this methodology for characterizing hair Hg levels in fish-eating populations is discussed.

Effect of combined spinal-epidural ambulatory labor analgesia on balance

BACKGROUND

Low-dose combined spinal-epidural analgesia in labor has proved popular with women because lower-limb motor power is preserved, allowing ambulation. However, there has been debate about the safety of allowing women to walk following low-dose regional analgesia because of somatosensory impairment. The authors undertook a prospective controlled observational study using computerized dynamic posturography to examine balance function in pregnant women after combined spinal-epidural analgesia.

METHODS

The authors performed posturographic testing on 44 women in labor after institution of regional analgesia and compared them with a control group of 44 pregnant women. A separate group of six women were tested both before and after combined spinal-epidural analgesia.

RESULTS

Neurologic examination after regional analgesia showed two parturients (4%) to have motor weakness (excluded from posturography). Four women (9%) had clinical dorsal column sensory loss; these women all completed posturography. The spinal-epidural analgesia group showed a small, statistically significant reduction in one of six posturographic sensory-organization tests; however, this difference was functionally minor. There were no other differences in posturography between the control and spinal-epidural groups. Similar results were found in the paired study, in which there was minimal change in balance function after spinal-epidural analgesia.

CONCLUSIONS

This is the first study to objectively examine the effect of spinal-epidural analgesia on balance function. Using computerized dynamic posturography, the authors were unable to find any functional impairment of balance function after spinal-epidural ambulatory analgesia in women in labor who had no clinical evidence of motor block.

LDL receptor gene expression in human mesangial cells under the influence of calcium channel blockers

BACKGROUND

Intracellular transport of lipid through the regulation of LDL receptor (LDLr) may be important in the progression of renal dysfunction.

METHODS

We explored LDLr gene expression in human mesangial cell line (HMCL) under influence of calcium channel blockers using cell proliferation, LDL binding, Northern blot and LDLr promoter activity assay.

RESULTS

Diltiazem and verapamil increased the expression of LDLr mRNA in a dose-dependent manner. Increased LDLr mRNA paralleled LDL binding. Nifedipine did not increase the expression of LDLr mRNA and LDL binding to HMCL at 1 - 100 micromol/l. The LDLr promoter activity assay showed that treatment with 100 micromol/ of diltiazem and verapamil increased LDLr promoter activity by 126.72 +/- 10.68%, and 166.41 +/- 11.41%, respectively, at 24 hours (control as 100%), while treatment with 100 micromol/l of nifedipine had an inhibitory effect on LDLr promoter activity. High concentration of LDL (250 microg/ml) inhibited promoter activity. Diltiazem or verapamil coincubated with LDL (250 microg/ml) could not override transcriptional inhibition by LDL. CCBs inhibited the proliferation of HMCL, therefore, CCBs-induced LDLr expression did not depend on a proliferative response. Signal transduction pathway experiments showed that the calmodulin transduction pathway was involved in LDLr upregulation induced by diltiazem or verapamil. Additionally, tyrosine kinase and PKC pathways were involved in the induction of LDLr induced by verapamil.

CONCLUSION

These studies show that diltiazem and verapamil increase LDLr gene transcription and expression which is independent of cell proliferation in HMCL.

Comparison of intrathecal and epidural diamorphine for elective caesarean section using a combined spinal-epidural technique

To assess calculated equivalent doses of intrathecal and epidural opioids for elective Caesarean section in terms of quality and duration of analgesia, and incidence of side effects, we have compared 50 patients, allocated randomly to one of two groups to receive either diamorphine 0.25 mg intrathecally (group 1) or 5 mg epidurally (group 2), in addition to intrathecal bupivacaine 10 mg, using a combined spinal-epidural technique. There was no significant difference in duration of analgesia between groups (group 1 mean 14.6 (SD 5.9) h, group 2 14.2 (6.5) h; mean difference 0.8 h; 95% Cl -2.8-4.5; P = 0.65) or quality of analgesia (VAPS and VRS scores). The degree of pruritus was similar in both groups (80-88%) but the incidence of postoperative nausea and vomiting was significantly higher in the epidural group (24% vs 4%; P < 0.05). Intrathecal diamorphine 0.25 mg produced the same duration and quality of postoperative analgesia as epidural diamorphine 5 mg for elective Caesarean section but with significantly less nausea and vomiting.