Effectiveness of a web-based virtual journal club to promote medical education (Web-Ed): protocol of a multicentre pragmatic randomised trial

INTRODUCTION

A journal club (JC) is a commonly used medical educational tool. Videoconferencing technology can facilitate the delivery of JCs, however, there remains no evidence on the role of web-based virtual JCs in promoting the acquisition and retention of medical knowledge. The Web-Ed trial aims to evaluate the educational benefits, feasibility and acceptability of web-based virtual JCs compared with traditional face-to-face ones.

METHODS AND ANALYSIS

Web-Ed is a multicentre pragmatic parallel-group randomised trial across teaching hospitals within the UK National Health Service (NHS). We will enrol qualified doctors or medical students who are >18 years old, proficient in English and able to use online videoconferencing software. Block randomisation will be used to allocate participants in 1:1 ratio to either intervention group. Both groups will be presented with the same educational material and follow a standardised JC structure hosted by nominated moderators and medical faculty members.The primary outcome is the difference in participants' knowledge acquisition and retention 7 days after the JCs evaluated using standardised multiple-choice questions. We will report secondarily on the feasibility and acceptability of the JCs using Likert scale questionnaires. Assuming a 30% drop-out rate, we aim to enrol 75 participants to detect a 20% improvement in knowledge acquisition at 80% power and 5% significance. We will report using mean difference or risk ratio with 95% CIs and assess significance using parametric/non-parametric testing. Where relevant, we will adjust for predetermined characteristics (age, grade of training and session duration) using multivariate regression analyses.

ETHICS AND DISSEMINATION

Web-Ed was designed by doctors in training to address their learning needs and evaluate the preferred mode of learning. The trial results will be published in peer-reviewed journals and presented at relevant scientific conferences. The trial has been approved by the NHS Health Regulation Authority (21/HRA/3361).

TRIAL REGISTRATION NUMBER

ISRCTN18036769.

Clinical management of deviations in maternal temperature during labour and childbirth: an evidence-based intrapartum care algorithm

AIM

The development of an evidence-based algorithm for the clinical management of deviations in maternal temperature during labour and childbirth.

POPULATION

Pregnant women at any stage of labour, with singleton, term (37-42 weeks) pregnancies at low risk of developing complications.

SETTING

Health facilities in low- and middle-income countries.

SEARCH STRATEGY

We searched for international guidelines and prioritised WHO guidelines. In addition, we searched for other sources of evidence in the Cochrane Database of Systematic Reviews, EMBASE, MEDLINE and CINAHL until June 2020. Studies were prioritised according to the hierarchy of evidence.

CASE SCENARIOS

Two case scenarios were identified: maternal hyperthermia and hypothermia. We developed a single algorithm including both, due to commonalities in diagnosis, monitoring and management of underlying causes. The underlying conditions covered in the pathway include maternal sepsis and infection, chorioamnionitis, pyelonephritis, lower urinary tract and respiratory infections. Key decision points in the algorithm are suspicion of condition, definition, differential diagnosis, monitoring and management.

CONCLUSIONS

We present an evidence-based algorithm to assist healthcare professionals in making decisions about appropriate clinical management of deviations in maternal temperature. Research is needed to assess the views of healthcare professionals and women accessing healthcare on the feasibility of implementing the algorithm.

TWEETABLE ABSTRACT

An evidence-based intrapartum care algorithm to support management of deviations in maternal temperature in labour and childbirth. #sepsis #maternitycare.

P139 Women's Health Care during COVID-19

Introduction

The coronavirus disease 2019 (COVID-19) pandemic is disrupting health services worldwide. Women's health care is often acute and in continual demand, with poor health outcomes seen in women's health in particular in the recent Ebola and Swine flu epidemics. Regrettably, early reports globally and in the UK have shown a rise in the stillbirth rate. We aimed to evaluate the provision of obstetrics and gynaecology services in the UK during the acute phase of the COVID-19 pandemic.

Methods

We undertook an interview-based national survey of junior doctors in obstetrics and gynaecology in women’s healthcare units in the National Health Service using the network of the UK Audit and Research Collaborative in Obstetrics and Gynaecology. We sought responses on general training, labour ward care, antenatal and postnatal care, benign gynaecology and gynaecology oncology services.

Results

We received responses from 148/155 units (95%) contacted. Most completed specific training drills for managing obstetric and gynaecological emergencies (89/148, 60.1%) and two-person donning and doffing of personal protective Equipment (PPE) (96/148, 64.9%). The majority of surveyed units implemented COVID-19-specific protocols (130/148, 87.8%), offered adequate PPE (135/148, 91.2%) and operated dedicated COVID-19 emergency theatres (105/148,70.8%). Most units suspended elective gynaecology services (131/148, 88.5%). The 2-week referral pathway for oncological gynaecology was not affected in half of the units (76/148,51.4%), but half reported a planned reduction in oncology surgery (82/148, 55.4%)

Discussion

Women's health care services have responded well to the acute phase of the COVID-19 pandemic, however further planning is required for the long term.

The FAST-M complex intervention for the detection and management of maternal sepsis in low-resource settings: a multi-site evaluation

OBJECTIVE

To evaluate whether the implementation of the FAST-M complex intervention was feasible and improved the recognition and management of maternal sepsis in a low-resource setting.

DESIGN

A before-and-after design.

SETTING

Fifteen government healthcare facilities in Malawi.

POPULATION

Women suspected of having maternal sepsis.

METHODS

The FAST-M complex intervention consisted of the following components: the FAST-M maternal sepsis treatment bundle and the FAST-M implementation programme. Performance of selected process outcomes was compared between a 2-month baseline phase and 6-month intervention phase with compliance used as a proxy measure of feasibility.

MAIN OUTCOME RESULT

Compliance with vital sign recording and use of the FAST-M maternal sepsis bundle.

RESULTS

Following implementation of the FAST-M intervention, women were more likely to have a complete set of vital signs taken on admission to the wards (0/163 [0%] versus 169/252 [67.1%], P < 0.001). Recognition of suspected maternal sepsis improved with more cases identified following the intervention (12/106 [11.3%] versus 107/166 [64.5%], P < 0.001). Sepsis management improved, with women more likely to receive all components of the FAST-M treatment bundle within 1 hour of recognition (0/12 [0%] versus 21/107 [19.6%], P = 0.091). In particular, women were more likely to receive antibiotics (3/12 [25.0%] versus 72/107 [67.3%], P = 0.004) within 1 hour of recognition of suspected sepsis.

CONCLUSION

Implementation of the FAST-M complex intervention was feasible and led to the improved recognition and management of suspected maternal sepsis in a low-resource setting such as Malawi.

TWEETABLE ABSTRACT

Implementation of a sepsis care bundle for low-resources improved recognition & management of maternal sepsis.

Development of the FAST-M maternal sepsis bundle for use in low-resource settings: a modified Delphi process

Objective

To develop a sepsis care bundle for the initial management of maternal sepsis in low resource settings.

Design

Modified Delphi process.

Setting

Participants from 34 countries.

Population

Healthcare practitioners working in low resource settings (n = 143; 34 countries), members of an expert panel (n = 11) and consultation with the World Health Organization Global Maternal and Neonatal Sepsis Initiative technical working group.

Methods

We reviewed the literature to identify all potential interventions and practices around the initial management of sepsis that could be bundled together. A modified Delphi process, using an online questionnaire and in‐person meetings, was then undertaken to gain consensus on bundle items. Participants ranked potential bundle items in terms of perceived importance and feasibility, considering their use in both hospitals and health centres. Findings from the healthcare practitioners were then triangulated with those of the experts.

Main outcome measure

Consensus on bundle items.

Results

Consensus was reached after three consultation rounds, with the same items deemed most important and feasible by both the healthcare practitioners and expert panel. Final bundle items selected were: (1) Fluids, (2) Antibiotics, (3) Source identification and control, (4) Transfer (to appropriate higher‐level care) and (5) Monitoring (of both mother and neonate as appropriate). The bundle was given the acronym ‘FAST‐M’.

Conclusion

A clinically relevant maternal sepsis bundle for low resource settings has been developed by international consensus.

Tweetable abstract

A maternal sepsis bundle for low resource settings has been developed by international consensus.

A maternal sepsis bundle for low resource settings has been developed by international consensus.

Weaning practices in phenylketonuria vary between health professionals in Europe

Background

In phenylketonuria (PKU), weaning is considered more challenging when compared to feeding healthy infants. The primary aim of weaning is to gradually replace natural protein from breast milk or standard infant formula with solids containing equivalent phenylalanine (Phe). In addition, a Phe-free second stage L-amino acid supplement is usually recommended from around 6 months to replace Phe-free infant formula. Our aim was to assess different weaning approaches used by health professionals across Europe.

Methods

A cross sectional questionnaire (survey monkey®) composed of 31 multiple and single choice questions was sent to European colleagues caring for inherited metabolic disorders (IMD). Centres were grouped into geographical regions for analysis.

Results

Weaning started at 17–26 weeks in 85% (n = 81/95) of centres, >26 weeks in 12% (n = 11/95) and < 17 weeks in 3% (n = 3/95). Infant's showing an interest in solid foods, and their age, were important determinant factors influencing weaning commencement. 51% (n = 48/95) of centres introduced Phe containing foods at 17–26 weeks and 48% (n = 46/95) at >26 weeks. First solids were mainly low Phe vegetables (59%, n = 56/95) and fruit (34%, n = 32/95).

A Phe exchange system to allocate dietary Phe was used by 52% (n = 49/95) of centres predominantly from Northern and Southern Europe and 48% (n = 46/95) calculated most Phe containing food sources (all centres in Eastern Europe and the majority from Germany and Austria). Some centres used a combination of both methods.

A second stage Phe-free L-amino acid supplement containing a higher protein equivalent was introduced by 41% (n = 39/95) of centres at infant age 26–36 weeks (mainly from Germany, Austria, Northern and Eastern Europe) and 37% (n = 35/95) at infant age > 1y mainly from Southern Europe. 53% (n = 50/95) of centres recommended a second stage Phe-free L-amino acid supplement in a spoonable or semi-solid form.

Conclusions

Weaning strategies vary throughout European PKU centres. There is evidence to suggest that different infant weaning strategies may influence longer term adherence to the PKU diet or acceptance of Phe-free L-amino acid supplements; rendering prospective long-term studies important. It is essential to identify an effective weaning strategy that reduces caregiver burden but is associated with acceptable dietary adherence and optimal infant feeding development.

What Proportion of Cancers in the UK and Its Constituent Countries Could Be Prevented? An Updated Analysis

Background: Understanding population-level exposure to cancer risk factors is vital when devising risk-reduction policies. By reducing exposure to cancer risk factors, many cancers could be prevented. But what impact on cancer incidence do these risk factors have? And what proportion of cancers could be prevented if these risk factors are avoided? Aim: The aim of this analysis was to update the estimates of the number and proportion of theoretically preventable cancers in the UK to reflect the changing behavior as assessed in representative national surveys, and new epidemiologic evidence. Separate estimates were also calculated for England, Wales, Scotland, and Northern Ireland because prevalence of risk factor exposure varies between them. Methods: Population attributable fractions (PAFs) were calculated for combinations of risk factor and cancer type with sufficient/convincing evidence of a causal association. Relative risks (RRs) were drawn from meta-analyses of cohort studies where possible. Prevalence of exposure to risk factors was obtained from nationally representative population surveys. Cancer incidence data for 2015 were sourced from national data releases and, where needed, personal communications. Results: Around four in ten (38%) cancer cases in 2015 in the UK were attributable to known risk factors. The proportion was around two percentage points higher in UK males (39%) than UK females (37%). Comparing UK countries, the attributable proportion for persons was highest in Scotland (41%) and lowest in England (37%). Tobacco smoking contributed by far the largest proportion of attributable cancer cases, followed by overweight and obesity, accounting for 15% and 6%, respectively, of all cases in the UK in 2015. Conclusion: Around four in ten (38%) cancer cases in the UK could be prevented. Tobacco and obesity remain the top contributors of attributable cancer cases. Tobacco smoking has the highest PAF because it greatly increases cancer risk and has a large number of cancer types associated with it. Obesity has the second-highest PAF because it affects a high proportion of the UK population and is also linked with many cancer types. Public health policy may seek to reduce the level of harm associated with exposure or reduce exposure levels - both approaches may be effective in preventing cancer. The variation in PAFs between UK countries is affected by sociodemographic differences which drive differences in exposure to theoretically avoidable 'lifestyle' factors. PAFs at UK country level have not been available previously and they should be used by policymakers in the devolved nations to develop more targeted public health measures. This analysis demonstrates the importance of nationally representative exposure prevalence data and cancer registration in informing evidence-based public health policy.

Early feeding practices in infants with phenylketonuria across Europe

Background

In infants with phenylketonuria (PKU), dietary management is based on lowering and titrating phenylalanine (Phe) intake from breast milk or standard infant formula in combination with a Phe-free infant formula in order to maintain blood Phe levels within target range. Professionals use different methods to feed infants with PKU and our survey aimed to document practices across Europe.

Methods

We sent a cross sectional, survey monkey® questionnaire to European health professionals working in IMD. It contained 31 open and multiple-choice questions. The results were analysed according to different geographical regions.

Results

Ninety-five centres from 21 countries responded. Over 60% of centres commenced diet in infants by age 10 days, with 58% of centres implementing newborn screening by day 3 post birth. At diagnosis, infant hospital admission occurred in 61% of metabolic centres, mainly in Eastern, Western and Southern Europe. Breastfeeding fell sharply following diagnosis with only 30% of women still breast feeding at 6 months.

53% of centres gave pre-measured Phe-free infant formula before each breast feed and 23% alternated breast feeds with Phe-free infant formula. With standard infant formula feeds, measured amounts were followed by Phe-free infant formula to satiety in 37% of centres (n = 35/95), whereas 44% (n = 42/95) advised mixing both formulas together. Weaning commenced between 17 and 26 weeks in 85% centres, ≥26 weeks in 12% and < 17 weeks in 3%.

Discussion

This is the largest European survey completed on PKU infant feeding practices. It is evident that practices varied widely across Europe, and the practicalities of infant feeding in PKU received little focus in the PKU European Guidelines (2017). There are few reports comparing different feeding techniques with blood Phe control, Phe fluctuations and growth. Controlled prospective studies are necessary to assess how different infant feeding practices may influence longer term feeding development.

Dietary management of urea cycle disorders: European practice

BACKGROUND

There is no published data comparing dietary management of urea cycle disorders (UCD) in different countries.

METHODS

Cross-sectional data from 41 European Inherited Metabolic Disorder (IMD) centres (17 UK, 6 France, 5 Germany, 4 Belgium, 4 Portugal, 2 Netherlands, 1 Denmark, 1 Italy, 1 Sweden) was collected by questionnaire describing management of patients with UCD on prescribed protein restricted diets.

RESULTS

Data for 464 patients: N-acetylglutamate synthase (NAGS) deficiency, n=10; carbamoyl phosphate synthetase (CPS1) deficiency, n=29; ornithine transcarbamoylase (OTC) deficiency, n=214; citrullinaemia, n=108; argininosuccinic aciduria (ASA), n=80; arginase deficiency, n=23 was reported. The majority of patients (70%; n=327) were aged 0-16y and 30% (n=137) >16y. Prescribed median protein intake/kg body weight decreased with age with little variation between disorders. The UK tended to give more total protein than other European countries particularly in infancy. Supplements of essential amino acids (EAA) were prescribed for 38% [n=174] of the patients overall, but were given more commonly in arginase deficiency (74%), CPS (48%) and citrullinaemia (46%). Patients in Germany (64%), Portugal (67%) and Sweden (100%) were the most frequent users of EAA. Only 18% [n=84] of patients were prescribed tube feeds, most commonly for CPS (41%); and 21% [n=97] were prescribed oral energy supplements.

CONCLUSIONS

Dietary treatment for UCD varies significantly between different conditions, and between and within European IMD centres. Further studies examining the outcome of treatment compared with the type of dietary therapy and nutritional support received are required.

Dietary management of urea cycle disorders: UK practice

BACKGROUND

There is no published data describing UK dietary management of urea cycle disorders (UCD). The present study describes dietary practices in UK inherited metabolic disorder (IMD) centres.

METHODS

Cross-sectional data from 16 IMD centres were collected by a questionnaire describing the management of UCD patients on prescribed protein-restricted diets.

RESULTS

One hundred and seventy-five patients [N-acetylglutamate synthase deficiency, n = 3; carbamoyl phosphate synthase deficiency (CPS), n = 8; ornithine transcarbamoylase deficiency (OTC), n = 75; citrullinaemia, n = 41; argininosuccinic aciduria (ASA), n = 36; arginase deficiency, n = 12] were reported; 70% (n = 123) aged 0-16 years; 30% (n = 52) >16 years. Prescribed median protein intake decreased with age (0-6 months: 2 g kg(-1) day(-1); 7-12 months: 1.6 g kg(-1) day(-1); 1-10 years: 1.3 g kg(-1) day(-1); 11-16 years: 0.9 g kg(-1) day(-1) and >16 years: 0.8 g kg(-1) day(-1)) with little variation between disorders. Adult protein prescription ranged 0.4-1.2 g kg(-1) day(-1) (40-60 g day(-1)). In the previous 2 years, 30% (n = 53) were given essential amino acid supplements (EAAs) (CPS, n = 2; OTC, n = 20; citrullinaemia, n = 15; ASA, n = 7; arginase deficiency, n = 9). EAAs were prescribed for low plasma quantitative essential amino acids (n = 13 centres); inadequate natural protein intake (n = 11) and poor metabolic control (n = 9). From diagnosis, one centre prescribed EAAs for all patients and one centre for severe defects only. Only 3% (n = 6) were given branch chain amino acid supplements. Enteral feeding tubes were used by 25% (n = 44) for feeds and 3% (n = 6) for medications. Oral energy supplements were prescribed in 17% (n = 30) of cases.

CONCLUSIONS

In the UK, protein restriction based on World Health Organization 'safe intakes of protein', is the principle dietary treatment for UCD. EAA supplements are prescribed mainly on clinical need. Multicentre collaborative research is required to define optimal dietary treatments.

Multiconjugate adaptive optics: laboratory experience

We present the results from a laboratory multiconjugate adaptive optics experiment. The experiment is differentiated from other published work in that it has a programmable deterministic turbulence generator and an output science camera. The turbulence was generated using a dual layer turbulence emulator, and then corrected using an AO system with 2 wavefront correctors and a Shack-Hartman wavefront sensor, which processed information from five artificial guide stars. We report our results and also describe some of the problems.

Dual-conjugate wavefront generation for adaptive optics

We present results of the isoplanatic performance of an astronomical adaptive optics system in the laboratory, by using a dual layer turbulence simulator. We describe how the performance of adaptive correction degrades with off--axis angle. These experiments demonstrate that it is now possible to produce quantifiable multi-layer turbulence in the laboratory as a precursor to constructing multi-conjugate adaptive optics.

Changes in anesthetic sensitivity and glutamate receptors in the aging canine brain

This study investigated whether the aging process in dogs is associated with an increased sensitivity to inhalation anesthesia and whether age-related changes in glutamate receptors are related to the increased sensitivity. The mean minimum alveolar concentration (MAC) of isoflurane was 1.82 +/- .08% for 2-3 year olds and 1.45 +/- .06% for 11 years olds, indicating that there was an increased potency of isoflurane in the older dogs as compared to the young. These older animals also showed a significant decrease in binding of [3H]glutamate and [3H]dizocilpine ([3H]MK801) to N-methyl-D-aspartate (NMDA) receptors in multiple cortical and hippocampal regions. The density of binding to NMDA receptors in the cortex, using a single concentration of ligand, correlated significantly with individual MAC values. These results demonstrate that dogs experience an increase in anesthetic potency with increased age, similar to humans, and that age-related changes in the NMDA receptor may represent one mechanism underlying this increased sensitivity to anesthesia.

A prospective randomized trial evaluating the haemodynamic role of incompetent calf perforating veins

AIM

This study was undertaken to determine the haemodynamic effect of incompetent calf perforating veins in patients with uncomplicated varicose veins and long saphenous incompetence.

METHODS

Thirty-eight limbs from 35 patients were studied. All patients had uncomplicated varicose veins with both long saphenous and calf perforator incompetence on duplex ultrasonography. Patients were randomized to have incompetent calf perforators ligated or left intact, in addition to saphenofemoral junction ligation, strip of long saphenous vein to knee and stab avulsion of any visible varicosities in the leg. Patients were assessed with air plethysmography pre-operatively and 3 months postoperatively.

RESULTS

Superficial venous surgery improved venous volume, venous filling index and ejection fraction in the patient cohort. No significant haemodynamic difference was demonstrated between the two groups of patients who were randomized.

CONCLUSIONS

At present, the results of this study do not support the use of routine perforator ligation during superficial surgery for uncomplicated varicose veins.

Paraoxonase active site required for protection against LDL oxidation involves its free sulfhydryl group and is different from that required for its arylesterase/paraoxonase activities: selective action of human paraoxonase allozymes Q and R

Human serum paraoxonase (PON 1) exists in 2 major polymorphic forms (Q and R), which differ in the amino acid at position 191 (glutamine and arginine, respectively). These PON allozymes hydrolyze organophosphates and aromatic esters, and both also protect LDL from copper ion-induced oxidation. We have compared purified serum PONs of both forms and evaluated their effects on LDL oxidation, in respect to their arylesterase/paraoxonase activities. Copper ion-induced LDL oxidation, measured by the production of peroxides and aldehydes after 4 hours of incubation, were reduced up to 61% and 58%, respectively, by PON Q, but only up to 46% and 38%, respectively, by an equivalent concentration of PON R. These phenomena were PON-concentration dependent. Recombinant PON Q and PON R demonstrated similar patterns to that shown for the purified serum allozymes. PON Q and PON R differences in protection of LDL against oxidation were further evaluated in the presence of glutathione peroxidase (GPx). GPx (0.1 U/mL) alone reduced copper ion-induced LDL oxidation by 20% after 4 hours of incubation. The addition of PON R to the above system resulted in an additive inhibitory effect on LDL oxidation, whereas PON Q had no such additive effect. The 2 PON allozymes also differed by their ability to inhibit initiation, as well as propagation, of LDL oxidation. PON Q was more efficient in blocking LDL oxidation if added when oxidation was initiated, whereas PON R was more potent when added 1 hour after the initiation of LDL oxidation. These data suggest that the 2 allozymes act on different substrates. Both PON allozymes were also able to reduce the oxidation of phospholipids and cholesteryl ester. PON Q arylesterase activity was reduced after 4 hours of LDL oxidation by only 28%, whereas the arylesterase activity of PON R was reduced by up to 55%. Inactivation of the calcium-dependent PON arylesterase activity by using the metal chelator EDTA, or by calcium ion removal on a Chelex column, did not alter PON's ability to inhibit LDL oxidation. However, blockage of the PON free sulfhydryl group at position 283 with p-hydroxymercuribenzoate inhibited both its arylesterase activity and its protection of LDL from oxidation. Recombinant PON mutants in which the PON free sulfhydryl group was replaced by either alanine or serine were no longer able to protect against LDL oxidation, even though they retained paraoxonase and arylesterase activities. Overall, these studies demonstrate that PON's arylesterase/paraoxonase activities and the protection against LDL oxidation do not involve the active site on the enzyme in exactly the same way, and PON's ability to protect LDL from oxidation requires the cysteine residue at position 283.

Traumatic retinopathy resembling acute macular neuroretinopathy

BACKGROUND

Acute macular neuroretinopathy (AMNR) is an uncommon disease of uncertain aetiology. We report on four males who developed unilateral changes following trauma which closely resembled acute macular retinopathy.

METHODS

Retrospective review of selected cases.

RESULTS

Four male patients developed a central or paracentral scotoma immediately or soon after an accident in which they suffered moderately severe bodily injury without direct ocular trauma. Vision was reduced in three patients. All four patients had characteristic well-circumscribed, dark macular lesions best seen using red-free light. The lesions cleared slowly in the two cases who returned for review.

CONCLUSIONS

A picture that closely resembles AMNR may be seen after trauma. The mechanism may involve a sudden rise in ocular venous pressure. This may be an unrecognized cause of visual loss after non-ocular trauma which may be regarded as functional. The subtle retinal lesions may be overlooked unless the fundi are examined in red-free light and the macular dark areas are compared.

Binary adaptive optics: atmospheric wave-front correction with a half-wave phase shifter

We describe a binary approach to adaptive wave-front correction, especially suitable for narrow band applications, which would be simpler than conventional adaptive technology. Appropriate parts of the aberrant wave front are phase retarded by half a wavelength to ensure that none of the image-forming rays add together destructively. Simulations for monochromatic light show that the residual wave-front errors, in the absence of other errors, would result in Strehl ratios of ~40% with diffraction-limited widths at visible wavelengths. We simulate the imaging performance of such a system and describe a possible implementation that uses a ferroelectric liquid-crystal spatial light modulator.

Clinical investigations of halothane and isoflurane for induction and maintenance of foal anesthesia

Fifty-eight foals were divided into two groups for study of aspects of the clinical anesthetic management of foals and to characterize effects of halothane (n = 30) and isoflurane (n = 28) in foals. There were no significant differences (P greater than 0.05) in the demographics of the two groups. Results of hemograms and biochemical analysis of venous blood samples before and after anesthesia were either not influenced or only mildly (clinically unimportant) affected by either agent. Like adult horses, foals have an increased PaCO2 when anesthetized with inhaled anesthetics. We could detect no difference in the magnitude of increase in PaCO2 with either anesthetic. Anesthetic induction and recovery was most rapid with isoflurane. The quality of induction and recovery was similarly acceptable with either agent. Heart rate during isoflurane was not significantly different from conscious conditions but during halothane, heart rate was significantly less than control except at 91-120 min when statistical significance was not detected. These results support the clinical impression that foals can be safely and reliably anesthetized with either agent.

Effects of five hours of constant 1.2 MAC halothane in sternally recumbent, spontaneously breathing horses

Circulatory and respiratory effects of five h of constant 1.06 per cent alveolar halothane in oxygen were identified in eight healthy horses, which breathed spontaneously, were otherwise unmedicated and positioned in sternal recumbency. Only a few important significant (P less than 0.05) changes occurred with time. Total peripheral resistance was about 15 per cent lower after two hours of constant dose halothane than after 30 mins of constant dose (P less than 0.05) and accounted for the significant 10 per cent reduction in mean carotid arterial blood pressure. By 5 h, the reduction in resistance and arterial blood pressure was 20 and 25 per cent respectively. Heart rate increased progressively with time and the increase became significant at 5 h (15 per cent increase). However, the heart rate change was not large enough to alter cardiac output. There were no major time-related changes in PaO2 or PaCO2. Three of four horses recovered from anaesthesia had markedly elevated serum creatine kinase levels and clinical signs of severe post anaesthetic myopathy.

Botulinum toxin--the rationale of its use

Treatment with Oculinum, (Botulinum toxin, Type A), may induce three possible effects. These are a pharmacologic inhibitory effect, a mechanical effect and a sensory effect.

Stereoscopic evoked responses to crossed and uncrossed disparity accompanying simulated refractive error

Evoked potentials were recorded to the occurrence of a disparate stimulus in dynamic random dot stereograms. Seven adult males, all of whom had vision which was normal or corrected to normal, participated in the experiment. Subjects viewed 100 ms duration stimuli which embodied 30 arc min of either crossed or uncrossed disparity under four conditions of spherical overcorrection: -0.25, +1.0, +2.0, +3.0 dioptres. The first condition, essentially normal refraction, yielded reliable behavioural reports of the stimulus and clear evoked potentials to both crossed and uncrossed disparity. With increasing overcorrection the behavioural reports became less reliable, and the evoked potentials were degraded for both conditions of disparity. The responses to the crossed disparity condition, however, showed significantly less degradation in both behavioural and electrophysiological measures. The implications of this finding may be that there are separate cortical subsystems for the processing of crossed and uncrossed disparity and that the former is more robust under non-ideal viewing conditions.

Botulinum toxin in ophthalmology

Alan B. Scott selected, researched and developed Type A Botulinum toxin for clinical use in ophthalmology. This unique drug has proved invaluable for treatment of a number of conditions which are difficult to treat in ophthalmology and in a variety of other disciplines. The indications, methods and problems of its use are described and the results of treatment of 133 patients are discussed. Up to December 1986 over 13,000 patients have been treated in a multicentre international trial without significant complications.

Exogenous ocular candidiasis associated with intravenous heroin abuse

Seven young men developed disseminated candidiasis within 10 days of a single episode of intravenous heroin abuse. Sequential development of eye and skin lesions was noted in all cases. The bone or costal cartilage was involved in five. Ocular manifestations of candidiasis included episcleritis, chorioretinitis, and endophthalmitis. A presumptive diagnosis of candida chorioretinitis was established rapidly by culture of Candida albicans from involved skin and costal cartilage. Systemic therapy with amphotericin B plus 5-fluorocytosine resulted in cure of the episcleritis, chorioretinitis, osteomyelitis, costochondritis, and skin infection. Pars plana vitrectomy with local instillation of amphotericin B was required to cure chorioretinitis associated with vitreal extension of infection.

Contractile properties and ultrastructure of extensor digitorum longus and soleus muscles in spinal cord transected rats

The spinal cord of rats 25 days of age was transected at the thoracic level, and the contractile properties as well as the ultrastructure of their extensor digitorum longus (EDL) and soleus muscles was examined. In the normally slow-twitch soleus muscle, the operation produces a marked reduction of contraction time as well as the appearance of other contractile characteristics of a fast-twitch muscle, namely, post-tetanic potentiation and cooling potentiation of the isometric twitch. This operation has little effect on the fast-twitch EDL. The ultrastructure of the EDL is similarly unaffected by the motor paralysis introduced by transection, but little change to the soleus structure was found, except for an increase in sarcoplasmic reticulum surface to fibre volume ratio. These results provide little evidence that muscle structure, especially the amount of sarcoplasmic reticulum, plays a major role in the determination of contractile speed, and confirms that structure may be regulated independently by the nerve.

A comparison of crown-rump length measurements using a real-time scanner in an antenatal clinic and a conventional B-scanner

In a series of 168 patients in the first trimester of pregnancy, fetal crown-rump length (CRL) measurements were attempted in the Antenatal Clinic using a linear-array real-time ultrasound scanner. The measurements could not be made in 23 of the patients; most of them had a gestational age of less than 10 weeks and the difficulty in obtaining measurements was usually due to an underfilled maternal bladder. When compared with CRL measurements obtained with a conventional B-scanner, a good correlation was obtained (r = 0.92); 80 per cent of the 'real-time' values fell within a range of +/- 5 mm of the conventional values. In all patients the estimates of gestational age using the two methods were within one week of each other.