Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides

The Salmonellae PhoP-PhoQ virulence regulators induce resistance to host cationic antimicrobial peptides (CAMP) after infection of vertebrate tissues, and Mg2+ or Ca2+ limitation. The PhoP-PhoQ activated gene, pagP, was identified as important to inducible CAMP resistance and increased acylation of lipid A, the major component of the outer leaflet of the outer membrane. pagP mutants demonstrated increased outer membrane permeability in response to CAMP, supporting the hypothesis that increased lipid A acylation is a CAMP resistance mechanism. Similarly, in response to Mg2+ limited growth, other enteric Gram-negative bacteria demonstrated increased lipid A acylation. Compounds that inhibit the ability to increase lipid A acylation may have utility as new antimicrobial agents.

Induction of AIDS in rhesus monkeys by molecularly cloned simian immunodeficiency virus

Better understanding of the pathogenesis of acquired immunodeficiency syndrome (AIDS) would be greatly facilitated by a relevant animal model that uses molecularly cloned virus of defined sequence to induce the disease. Such a system would also be of great value for AIDS vaccine research. An infectious molecular clone of simian immunodeficiency virus (SIV) was identified that induces AIDS in common rhesus monkeys in a time frame suitable for laboratory investigation. These results provide another strong link in the chain of evidence for the viral etiology of AIDS. More importantly, they define a system for molecular dissection of the determinants of AIDS pathogenesis.

Effectiveness of a community-directed 'healthy lifestyle' program in a remote Australian aboriginal community

OBJECTIVE

To assess the sustainability and effectiveness of a community-directed program for primary and secondary prevention of obesity, diabetes and cardiovascular disease in an Aboriginal community in north-west Western Australia.

METHOD

Evaluation of health outcomes (body mass index, glucose tolerance, and plasma insulin and triglyceride concentrations) in a cohort of high-risk individuals (n = 49, followed over two years) and cross-sectional community samples (n = 200 at baseline, 185 at two-year and 132 at four-year follow-ups), process (interventions and their implementation) and impact (diet and exercise behaviour).

RESULTS

For the high-risk cohort, involvement in diet and/or exercise strategies was associated with protection from increases in plasma glucose and triglycerides seen in a comparison group; however, sustained weight loss was not achieved. At the community level, significant reductions were observed in fasting insulin concentration but no change in prevalence of diabetes, overweight or obesity. Weight gain remained a problem among younger people. Sustainable improvements were observed for dietary intake and level of physical activity. These changes were related to supportive policies implemented by the community council and store management.

CONCLUSIONS

Community control and ownership enabled embedding and sustainability of program, in association with social environmental policy changes and long-term improvements in important risk factors for chronic disease.

IMPLICATIONS

Developmental initiatives facilitating planning, implementation and ownership of interventions by community members and organisations can be a feasible and effective way to achieve sustainable improvements in health behaviours and selected health outcomes among Aboriginal people.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Self-contained Kondo effect in single molecules

Kondo coupling of and conduction electrons is a common feature of f-electron intermetallics. Similar effects should occur in carbon ring systems (metallocenes). Evidence for Kondo coupling in Ce(C(8)H(8)(2) (cerocene) and the ytterbocene Cp*(2) Yb(bipy) is reported from magnetic susceptibility and L(III)-edge x-ray absorption spectroscopy. These well-defined systems provide a new way to study the Kondo effect on the nanoscale, should generate insight into the Anderson Lattice problem, and indicate the importance of this often-ignored contribution to bonding in organometallics.

Myocardial infarction with normal coronary arteries is common and associated with normal findings on cardiovascular magnetic resonance imaging: results from the Stockholm Myocardial Infarction with Normal Coronaries study

OBJECTIVES

Myocardial infarction with angiographically normal coronary arteries (MINCA) is an important subtype of myocardial infarction; however, the prevalence, underlying pathophysiology, prognosis and optimal management of this condition are still largely unknown. Cardiovascular magnetic resonance (CMR) imaging has the potential to clarify the underlying pathology in patients with MINCA. The objective of this study was to investigate the diagnostic value of CMR imaging in this group of patients.

DESIGN

The prospective, multicentre, observational Stockholm Myocardial Infarction with Normal Coronaries (SMINC) study.

SETTING

Coronary care units in the Stockholm metropolitan area.

SUBJECTS

Patients between 35 and 70 years of age with MINCA were consecutively included in the screening phase of the SMINC study. All patients had a typical clinical presentation, fulfilling the universal definition of myocardial infarction and had normal coronary angiography finding. Patients with known structural or coronary heart disease or other known causes of elevated troponin levels were excluded.

RESULTS

In total, 176 patients with MINCA were screened from 2007 to 2011. Of these, 152 underwent CMR imaging. The investigation was performed a median of 12 (interquartile range 6-28) days after hospital admission; 67% of the findings were normal, whereas 19% of patients had signs of myocardial necrosis and 7% had signs of myocarditis. The remaining patients (7%) had either unrecognized hypertrophic cardiomyopathy or could not be classified.

CONCLUSION

In this consecutive series of patients with MINCA, CMR imaging may help to differentiate between those with myocarditis, myocardial necrosis and normal myocardium. The incidence of MINCA was higher than previously reported. After excluding cases of myocarditis, MINCA consists of a large group of patients with normal CMR imaging results and a smaller group with myocardial necrosis. The aetiologies of these different imaging findings need to be explored.

Labelling of peripheral-type benzodiazepine binding sites in human brain with [3H]PK 11195: anatomical and subcellular distribution

The peripheral-type benzodiazepine binding site, erstwhile characterized in the rodent and feline brain, has now been characterized in post-mortem human brain using [3H]PK 11195. The kinetics and pharmacological properties of the binding of this ligand are similar to peripheral-type benzodiazepine binding sites elsewhere. The potency of RO5-4864 for this site in human brain is close to that seen in ruminant and carnivore tissues but considerably lower than in rodent tissues. The regional distribution of these binding sites would suggest a neuronal rather than a glial localization. [3H]PK 11195 bound in a similar fashion to slide-mounted sections of human brain, thus allowing quantitative studies of the regional distribution of peripheral-type benzodiazepine binding sites to be made. The binding sites were distributed heterogeneously, but were restricted to the grey matter. Highest densities of binding sites were found in forebrain structures. The localization was not limited to any functional system, nor did it resemble any previously described transmitter system. The similarities between peripheral-type benzodiazepine binding sites in human and in feline brain in terms of their pharmacological characteristics and their regional and subcellular distribution suggest that the cat, rather than the rat, may be the better model for studying a possible role for this site in human cerebral function.

Diabetes incidence in an Australian aboriginal population. An 8-year follow-up study

OBJECTIVE

To examine prospectively the association between age, BMI, and subsequent incidence of type 2 diabetes in Australian aboriginal people.

RESEARCH DESIGN AND METHODS

We performed a stratified analysis of incidence data from a community-based longitudinal study. Measures included fasting and 2-h postload glucose concentrations, and BMI, stratified into four categories. Subjects were 882 male and female participants in diabetes screening initiatives in two remote Australian aboriginal communities, free from diabetes at baseline, ages 15-77 years.

RESULTS

There were 46 incident cases of diabetes over 2,808 person-years of follow-up. BMI modified strongly the sex- and community-adjusted association between age and diabetes incidence (P < 0.001). Adjusted for age, sex, and community, the population diabetes incidence rate was 20.3 cases/1,000 person-years, with BMI-specific rates of 10.7-47.2 cases/1,000 person-years, and relative risks (95% CI) for BMI strata beyond the reference category (< 25 kg/m2) of 3.3 (1.5-7.0), 2.7 (1.1-6.8), and 4.4 (1.7-11.6), respectively. The population's attributable risk (95% CI) associated with BMI beyond the reference category was 70.1% (58.1-82.4).

CONCLUSIONS

BMI-specific diabetes incidence rates in Australian aboriginal people are among the highest in the world. Diabetes incidence in the lowest BMI category (10.7 cases/1,000 person-years) is two to five times greater than corresponding rates for non-aboriginal populations. An urgent need exists to prevent weight gain associated with diabetes. Further study is required to determine for aboriginal people an optimal range of BMI, likely lower than that suggested for non-aboriginal populations.

Airway, feeding and growth in infants with Robin sequence and sleep apnoea

OBJECTIVE

Robin sequence (RS) is associated with airway abnormalities that result in functional problems of obstructive sleep apnoea (OSA), feeding difficulties, and consequent poor growth. We evaluated the relationships between OSA severity, airway and feeding interventions, and weight at 12 months in infants with RS and OSA.

METHODS

Retrospective notes review of children with RS managed at our neonatal unit (1998-2010, inclusive).

RESULTS

Of 39 infants studied, 10 (25.6%) had mild/moderate OSA, and 29 (74.4%) severe. Infants with severe OSA required more airway interventions in hospital (82.8 vs 30.0%, p = 0.004) and at discharge (72.4 vs 20.0%, p = 0.007) than those with mild/moderate OSA; 30.0% of infants with mild/moderate OSA required continuous positive airway pressure (CPAP) during admission and 20.0% on discharge, but amongst those with severe OSA 82.8% required airway interventions as an inpatient, 17.2% underwent mandibular distraction osteogenesis, and 55.2% required CPAP on discharge. Those with severe OSA were also more likely to require tube feeding on discharge (89.7 vs 50.0%, p = 0.02). Overall, children were on a lower weight centiles at discharge compared to birth (-10.2 centiles) and at 12 months of age compared to birth (-14.8 centiles), but this occurred irrespective of OSA severity or need for airway interventions or tube feeding.

CONCLUSIONS

Infants with RS commonly have OSA, feeding and airway difficulties. Weight at 12 months appeared not to be influenced by OSA severity, feeding or airway problems, suggesting that current intervention/management strategy results in the severely affected infants growing as well as those affected less severely.

Induced synthesis of metallothionein by pig kidney cells in vitro in response to cadmium

Cells of a line (K7), derived from the cortex of the adult pig kidney, synthesize and accumulate high levels of metallothionein when grown in vitro in the presence of low concentrations (0.5 mug/ml) of Cd2+. This indicates that the accumulation of this protein in the kidneys of animals exposed to cadmium is due at least partly to synthesis in situ, and not solely to uptake by the renal cells of metallothionein produced by the liver. It is suggested that the ability to synthesize large amounts of metallothionein indicates the tubular origin of the cells of this line.

Lyme borreliosis habitat assessment

Tick ecologists throughout Europe provided descriptions of Lyme borreliosis habitats according to a standardised format and data for 105 habitats in 16 countries were received. The data showed that high risk situations, as defined by the presence of large numbers of B. burgdorferi sensu lato-infected nymphal I. ricinus, occur in heterogeneous deciduous woodland, usually with a recreational function and with a diverse fauna, usually including deer. Large numbers of ticks occurred in some other habitats, but infection prevalence was usually low. The situation for adult I. ricinus was similar but less clearly defined. Tick infection rates were found to be lower in western Europe than in the east, and the infection rate in I. persulcatus, the most easterly vector species, was markedly higher than in I. ricinus. In the vast majority of habitats the infection rate in adult I. ricinus was greater than in nymphs. Larvae were rarely found to be infected.

Mathematical estimation of stress distribution in normal and dysplastic human hips

By using a mathematical model of the adult human hip in the static one-legged stance position of the body, the forces acting on the hip, peak stress in the hip joint and other relevant radiographic and biomechanical parameters were assessed. The aims were to examine if the peak stress in dysplastic hips is higher than in normal hips and to find out which biomechanical parameters contribute significantly to higher peak stress. The average normalized peak stress in dysplastic hips (7.1 kPa/N) was markedly higher (to approximately 100%) than the average normalized peak stress in normal hips (3.5 kPa/N). The characteristic parameters that contributed to higher peak stress in dysplastic hips included the smaller lateral coverage of the femoral head, the larger interhip distance, the wider pelvis, and the medial position of the greater trochanter. These results are consistent with the hypothesis that stress distribution over weight-bearing surface of the hip joint is the relevant parameter for assessment of the risk for developing coxarthrosis.

Fentanyl, esmolol, and clonidine blunt the transient cardiovascular stimulation induced by desflurane in humans

BACKGROUND

A rapid increase in the end-tidal concentration of desflurane to greater than 1 MAC transiently increases heart rate, arterial blood pressure, and circulating epinephrine and vasopressin concentrations. We hypothesized that drugs that block sympathetic activity or decrease sympathetic outflow (an opioid, a beta-adrenergic antagonist, and an alpha 2-adrenergic agonist) would blunt these responses.

METHODS

After induction of anesthesia with intravenous propofol 2 mg/kg in ten healthy male volunteers age 25 +/- 1 yr (mean +/- standard error), anesthesia was maintained with 4% end-tidal desflurane in oxygen (0.55 MAC) via an endotracheal tube for 32 min. Controlled ventilation provided normocapnia. We then increased the end-tidal desflurane concentration within 1 min to 8% (1.1 MAC) and maintained this concentration for 10 min. On separate days, five of these volunteers were similarly anesthetized except that 5 min before the increase to 8% desflurane, we administered intravenous fentanyl 1.5 micrograms/kg and on another day 4.5 micrograms/kg (dose randomly assigned). On 2 separate days, intravenous esmolol 0.75 mg/kg was given to five volunteers 1.5 min before, or clonidine 4.3 micrograms/kg by mouth to four volunteers 90 min before, the increase from 4% to 8% desflurane.

RESULTS

Without pretreatment, the increase to 8% desflurane increased heart rate (from 57 +/- 2 to 118 +/- 6 beats/min at peak, mean +/- standard error) and mean arterial blood pressure (from 66 +/- 2 to 118 +/- 5 mmHg). At the time of peak hemodynamic changes (within 1-2 min of the increase in desflurane concentration), plasma epinephrine and norepinephrine concentrations increased (from 22 +/- 6 to 339 +/- 83 pg/ml and from 205 +/- 19 to 283 +/- 30 pg/ml, respectively). Fentanyl 1.5 and 4.5 micrograms/kg attenuated the heart rate increase by 61 +/- 14% and 70 +/- 7% and the mean arterial blood pressure increase by 31 +/- 16% and 46 +/- 11% but did not alter the epinephrine or norepinephrine response at the time of peak cardiovascular changes. Esmolol attenuated the heart rate response but no other response. Clonidine attenuated all responses except that of norepinephrine and also caused postanesthesia sedation.

CONCLUSIONS

Fentanyl, esmolol, and clonidine blunt the transient cardiovascular response to a rapid increase in desflurane concentration. Fentanyl may be the most clinically useful of these drugs because it blunts the increase in heart rate and blood pressure, has minimal cardiovascular depressant effects, and imposes little postanesthetic sedation.

Assessment of level of consciousness following severe neurological insult. A comparison of the psychometric qualities of the Glasgow Coma Scale and the Comprehensive Level of Consciousness Scale

An alternative method of coma assessment is presented and compared with the Glasgow Coma Scale. The merits of the Comprehensive Level of Consciousness Scale as a research tool are presented. An analysis of 101 consecutive consciousness-impaired patients with their short-term outcome is presented.

Effectiveness of community-directed diabetes prevention and control in a rural Aboriginal population in British Columbia, Canada

This report presents the process and summative evaluation results from a community-based diabetes prevention and control project implemented in response to the increasing prevalence and impact of non-insulin-dependent diabetes mellitus (NIDDM) in the Canadian Aboriginal population. The 24-month project targeted the registered Indian population in British Columbia's rural Okanagan region. A participatory approach was used to plan strategies by which diabetes could be addressed in ways acceptable and meaningful to the intervention community. The strategies emphasised a combination of changing behaviours and changing environments. The project was quasi-experimental. A single intervention community was matched to two comparison communities. Workers in the intervention community conducted interviews of individuals with or at risk for diabetes during a seven-month pre-intervention phase (n = 59). Qualitative analyses were conducted to yield strategies for intervention. Implementation began in the eighth month of the project. Trend measurements of diabetes risk factors were obtained for 'high-risk' cohorts (persons with or at familial risk for NIDDM) (n = 105). Cohorts were tracked over a 16-month intervention phase, with measurements at baseline, the midpoint and completion of the study. Cross-sectional population surveys of diabetes risk factors were conducted at baseline and the end of the intervention phase (n = 295). Surveys of community systems were conducted three times. The project yielded few changes in quantifiable outcomes. Activation of the intervention community was insufficient to enable individual and collective change through dissemination of quality interventions for diabetes prevention and control. Theory and previous research were not sufficiently integrated with information from pre-intervention interviews. Interacting with these limitations were the short planning and intervention phases, just 8 and 16 months, respectively. The level of penetration of the interventions mounted was too limited to be effective. Attention to process is warranted and to the feasibility of achieving effects within 24 months.

Do mother's education and foreign born status interact to influence birth outcomes? Clarifying the epidemiological paradox and the healthy migrant effect

INTRODUCTION

The unresolved "epidemiological paradox" concerns the association between low socioeconomic status and unexpectedly favourable birth outcomes in foreign born mothers. The "healthy migrant" effect concerns the association between foreign born status per se and birth outcomes. The epidemiological paradox and healthy migrant effect were analysed for newborns in a favourable sociopolitical environment.

METHODS

98,330 live births to mothers in Montreal, Canada from 1997 to 2001 were analysed. Mothers were categorised as foreign born versus Canadian born. Outcomes were: small for gestational age (SGA) birth; low birth weight (LBW) and preterm birth (PTB). Multilevel logistic regression was used to examine the interaction between maternal education and foreign born status, adjusting for covariates.

RESULTS

Not having a high school diploma was associated with LBW in Canadian (odds ratio (OR) 3.20; 95% CI 2.61 to 3.91) but not foreign born (OR 1.14; 95% CI 0.99 to 2.10) mothers and was more strongly associated with SGA birth in Canadian (OR 2.03; 95% CI 1.84 to 2.22) than in foreign born (OR 1.26; 95% CI 1.07 to 1.49) mothers. Foreign born status was associated with SGA birth (OR 1.37; 95% CI 1.28 to 1.47), LBW (OR 1.51; 95% CI 1.27 to 1.79) and PTB (OR 1.12; 95% CI 1.03 to 1.22) in university-educated mothers only.

CONCLUSIONS

The epidemiological paradox associated with low educational attainment was present for SGA birth and LBW but not PTB. Foreign born status was associated with adverse birth outcomes in university-educated mothers, the opposite of the healthy migrant effect.

Diabetes and impaired glucose tolerance in Aboriginal Australians: prevalence and risk

The prevalence and risk of having impaired glucose tolerance (IGT) and diabetes was estimated relative to body mass index (BMI) among Australian Aboriginal people. A stratified analysis was undertaken of community screening data. Measures included fasting and 2-h glucose concentrations, and BMI (five strata: <22, 22-24.9, 25-29.9, 30-34.9 and >/=35 kg/m(2)). Age was stratified into three groups: 15-34.9, 35-44.9, and >/=45 years. Participants were men and women, ages 15-94 years (n=2626). The prevalence of IGT and diabetes, respectively, adjusted for age and BMI, was 139 and 142 cases/1000 persons among men, and 157 and 152 cases/1000 persons among women. Odds ratios (95% CI) for IGT and diabetes for increasing BMI strata >/=22 kg/m(2) ranged from 1.7 (1.0 to 2.9) to 5.1 (2.4-10.5) for IGT, and from 2.0 (1.2-3.5) to 6.1 (3.3-11.1) for diabetes. For IGT and diabetes, across genders, the population attributable risk percentages (95% CI) for BMI >/=22 kg/m(2) were 34.1% (26.2-41.9%) for IGT, and 46.4% (38.5-54.5%) for diabetes. Diabetes and IGT have reached epidemic proportions among Australian Aboriginal people. An urgent need exists for programmes to reduce the prevalence of diabetes risk factors, especially BMI of 22 kg/m(2) or more, a limit lower than advocated for Euro-American populations.

Fentanyl augments the blockade of the sympathetic response to incision (MAC-BAR) produced by desflurane and isoflurane: desflurane and isoflurane MAC-BAR without and with fentanyl

BACKGROUND

Heart rate (HR) or mean arterial blood pressure (MAP) may increase in response to incision despite the absence of a motor response. The authors hypothesized that the MAC-BAR (minimum alveolar concentration of an anesthetic that blocks adrenergic response to incision) for isoflurane would exceed that for desflurane, and that fentanyl would decrease the MAC-BAR for each anesthetic in a dose-dependent manner.

METHODS

Seventy-one patients were randomly allocated to one of six groups: desflurane or isoflurane without fentanyl or with 1.5 or 3 microg/kg fentanyl given intravenously 5 min before surgical incision. Anesthesia was induced with 2 mg/kg propofol given intravenously, and tracheal intubation facilitated with 0.1 mg/kg given intravenously. The first patient in each group received 1 MAC (end-tidal) of the inhaled anesthetic in 60% nitrous oxide (0.55 MAC), balance oxygen, maintained for at least 10 min before incision. The response was considered positive if the HR or MAP increased 15% or more. If the response was positive, the end-tidal concentration given to the next patient was 0.3 MAC greater; if the response was negative, the end-tidal concentration was 0.3 MAC less. The MAC-BAR level was calculated as the mean of four independent cross-over responses in each group.

RESULTS

Desflurane and isoflurane anesthesia with 60% nitrous oxide did not change HR (P > 0.05) and decreased MAP (P < 0.05) before incision. Plasma epinephrine and norepinephrine concentrations after anesthesia and before incision were normal in all groups. The MAC-BAR level, without fentanyl, did not differ (P > 0.05) between desflurane (1.30 +/- 0.34 MAC [mean +/- SD]) and isoflurane (1.30 +/- 0.18 MAC). Fentanyl given at 1.5 microg/kg intravenously equivalently (P > 0.05) reduced the MAC-BAR for desflurane (to 0.40 +/- 0.18 MAC; P < 0.05) and isoflurane (to 0.55 +/- 0.00 MAC; P < 0.05), but a further increase in fentanyl to 3 microg/kg caused no greater decrease in the MAC-BAR for desflurane (0.48 +/- 0.16 MAC) and isoflurane (0.40 +/- 0.30 MAC).

CONCLUSIONS

Clinically attainable doses of desflurane and isoflurane, in 60% nitrous oxide (0.55 MAC), block the cardiovascular response to surgical incision at 1.3 MAC. Fentanyl given at 1.5 microg/kg decreases the MAC-BAR for each agent with no further decrease produced by 3 microg/kg fentanyl.

Amino acid sequences of bacterial cytochromes c' and c-556

The cytochrome c' are electron transport proteins widely distributed in photosynthetic and aerobic bacteria. We report the amino acid sequences of the proteins from 12 different bacterial species, and we show by sequences that the cytochromes c-556 from 2 different bacteria are structurally related to the cytochromes c'. Unlike the mitochondrial cytochromes c, the heme binding site in the cytochromes c' and c-556 is near the COOH terminus. The cytochromes c-556 probably have a methionine sixth heme ligand located near the NH2 terminus, whereas the cytochromes c' may be pentacoordinate. Quantitative comparison of cytochrome c' and c-556 sequences indicates a relatively low 28% average identity.

The introduction of a surgical safety checklist in a tertiary referral obstetric centre

BACKGROUND Surgery-related adverse events remain a significant and often under-reported problem. In a recent study, the introduction of a perioperative checklist by the WHO reduced deaths and complications by 46% and 36% respectively. The authors wished to evaluate the introduction of a surgical safety checklist in a busy obstetric tertiary referral centre by assessing staff attitudes, checklist compliance and effects upon patients. METHODS A questionnaire-based assessment was performed on staff working in obstetric theatres before and after the introduction of the surgical safety checklist. Checklist compliance was assessed at 3&emsp14;months and 1&emsp14;year. Patients were asked questions relating to the performance of the surgical safety checklist in order to evaluate any anxiety caused. RESULTS Non-medical staff were significantly more likely than medical staff to feel familiar with other team members both before (p<0.001) and after (p=0.03) the introduction of the checklist. 69.6% of all staff felt that interprofessional communication had improved following the introduction of the checklist. Compliance with pre- and postoperative checks was 61.2% and 67.6%, respectively, improving to 79.7% and 84.7% after 1&emsp14;year. Although the majority of patients were aware of the checks being performed, this did not provoke anxiety. CONCLUSION Following consultation with staff and patients, the authors managed to institute and sustain the performance of a surgical safety checklist for elective cases in obstetric theatres. While significant progress has been made, the authors recognise that further work is required in order to further evaluate and optimise this process.

Sympathetic nervous system does not mediate reflex pupillary dilation during desflurane anesthesia

BACKGROUND

Pupil size is determined by an interaction between the sympathetic and parasympathetic divisions of the autonomic nervous system. Noxious stimulation dilates the pupil in both unanesthetized and anesthetized humans. In the absence of anesthesia, dilation is primarily mediated by the sympathetic nervous system. In contrast, pupillary dilation in cats given barbiturate or cloralose anesthesia is mediated solely by inhibition of the midbrain parasympathetic nucleus. The mechanism by which noxious stimuli dilate pupils during anesthesia in humans remains unknown. Accordingly, the authors tested the hypothesis that the pupillary dilation in response to noxious stimulation during desflurane anesthesia is primarily a parasympathetic reflex.

METHODS

In six volunteers, the alpha-I adrenergic receptors of the iris musculature were blocked by unilateral administration of topical dapiprazole; six other volunteers were given unilateral topical tropicamide to block the muscarinic receptors in the iris. Desflurane anesthesia was subsequently induced in all volunteers. Sympathetic nervous system activation, with reflex dilation of the pupil, was produced by noxious electrical stimulation during 4% and 8% end-tidal desflurane, and by a rapid 4%-to-8% step-up in the desflurane concentration. Pupil diameter and the change in pupil size induced by a light stimulus (light reflex amplitude) were measured with infrared pupillometry.

RESULTS

Dapiprazole drops produced a Horner's miosis, but pupils were equally small after induction of anesthesia. Pupillary dilation after noxious stimulation and desflurane step-up was identical in the unblocked and dapiprazole-blocked pupils. After tropicamide administration, the pupil was dilated and the light reflex was completely inhibited. Noxious stimulation nonetheless produced a slight additional dilation.

CONCLUSIONS

During desflurane anesthesia, pupillary dilation in response to noxious stimulation or desflurane step-up is not mediated by the sympathetic nervous system (as it is in unanesthetized persons). Although inhibition of the pupillo-constrictor nucleus may be the cause of this dilation, the mechanism remains unknown.