Going paperless: improved cataract surgery outcome data quality in a new fully electronic unit

OBJECTIVES

To report outcome data on the first 5000 consecutive cataract cases at a new paperless eye unit and benchmark against the Royal College of Ophthalmologists' National Ophthalmology Database (RCOphth NOD).

METHODS

Using the in-built audit tool of the electronic medical records system, data from all cataract operations performed between 1 April 2014 and 13 January 2017 were compiled.

RESULTS

Five thousand and eight cases were recorded of which the overall intra-operative complication rate was 2.4%, the most common being posterior capsular rupture-1.14%. Follow-up data on post-operative complications were recorded in 98.6% of cases. Pre- and post-operative visual acuities was measured in 98.0% of cases. In all, 40.8% of eyes achieved a visual acuity of 6/6 or better and 90.7% achieved 6/12 or better.

CONCLUSIONS

A data set of >5000 consecutive cataract operations was obtained in this eye department. The recording of pre- and post-operative visual acuity in 98% of cases compare very favourably to the RCOphth NOD Audit Report 2017 where pre- and post-operative visual acuities were recorded in only 57.1% of operations. Despite this difference, the outcome measures from this unit and RCOphth NOD were very similar, validating the results of the RCOphth NOD audit reports. Significantly, when applying the RCOphth NOD audit criteria for measuring post-operative visual acuity, approximately 15% of cases were excluded from the data set, reducing the completeness of the data set. Paperless ophthalmology units are feasible in today's NHS and can produce near complete cataract data sets; this can ultimately lead to more comprehensive and reliable aggregate cataract outcome data.

Pre-transplant predictors of one yr weight gain after kidney transplantation

Clinically useful predictors of weight gain could be used to reduce the epidemic of post-kidney transplant obesity and resulting co-morbidities. The purpose of this study was to identify predictors of weight gain at 12 months following kidney transplant in a cohort of 96 recipients. Demographic, clinical, and environmental data were obtained at transplant and 12 months. Descriptive, correlational, and Bayesian network analysis were used to identify predictors. For the 52 (55.9%) recipients who gained weight, the average amount gained was 9.18 ± 6.59 kg. From the 15 baseline factors that met inclusion criteria, Bayesian network modeling identified four baseline predictors for weight gain: younger age, higher carbohydrate consumption, higher trunk fat percentage, and higher perception of mental health quality of life. Three are modifiable through either pre- or immediate post-transplant clinical intervention programs.

Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

Novel CDH3 mutations in hypotrichosis with juvenile macular dystrophy

BACKGROUND

Hypotrichosis with juvenile macular dystrophy (HJMD) is a rare autosomal recessive disorder characterized by sparse and short hair, heralding progressive degeneration of the retinal pigment epithelium, which leads to blindness by the second decade of life. The disorder is caused by mutations in CDH3, a gene encoding P-cadherin, a major component of adherens junctions. Most HJMD cases reported to date have been shown to be caused by homozygous CDH3 mutations segregating in consanguineous families.

AIM AND METHODS

To elucidate the genetic basis of HJMD in two nonconsanguineous families, we established the coding sequence of CDH3 in four patients and their healthy siblings.

RESULTS

The four patients demonstrated markedly variable degrees of visual acuity impairment. Novel biallelic recessive mutations were identified in all affected individuals. One patient in the first family was found to carry two heterozygous mutations, IVS2 + 1G-->A and p.E504K; the other three patients in the second family were compound heterozygous for a missense mutation, p.H575R, and a nonsense mutation, p.R221X.

CONCLUSION

This paper expands the spectrum of known mutations in CDH3 and points to the existence of clinical heterogeneity in this syndrome.

Sexual dimorphism in the rabbit masseter muscle: myosin heavy chain composition of neuromuscular compartments

The myosin heavy chain (MyHC) isoform composition of six adult (>7 months old) male and female rabbit masseter muscles was studied using seven monoclonal antibodies. In matched serial tissue sections, muscle fibers in 10 different neuromuscular compartments were analyzed. Nearly all fibers were found to express one of five phenotypes. They either contained one of four different slow/beta MyHC phenotypes (I(1)-I(4)), nearly all of which co-express cardiac alpha MyHC, or they contained type IIa MyHC. Very few fibers contained slow/beta or cardiac alpha MyHC only or both the alpha/slow/beta and IIa isoforms. Most, but not all, of the compartments studied contained similar proportions of fibers of the five major phenotypes, at least within sex. For 7 of the 10 compartments studied, significant sex differences in the proportion of I(1) and IIa fibers were found. Males contained more IIa fibers and fewer I(1) fibers than females. Fibers of the IIa phenotype were significantly larger than fibers of all of the other phenotypes and larger in males than females.

Virtual electrode effects in transvenous defibrillation-modulation by structure and interface: evidence from bidomain simulations and optical mapping

INTRODUCTION

Our goal in this combined modeling and experimental study was to gain insight into the transmembrane potential changes in defibrillation conditions, namely, when shocks are delivered by an implantable cardioverter defibrillator (ICD). Two hypotheses concerning the presence and characteristics of virtual electrode effects (VEE) during an ICD shock were tested numerically and experimentally: (H1) anisotropy-dependent VEE are induced over a considerable portion of the "bulk" myocardium; and (H2) surface (epicardial and endocardial) VEE are generated under special tissue bath conditions and are not fully anisotropy determined.

METHODS AND RESULTS

Optical mapping was performed on Langendorff-perfused rabbit hearts (n = 4) stained with di-4-ANEPPS. Monophasic shocks were applied during the plateau phase of an action potential through a 9-mm long distal electrode in the right or left ventricle and a 6-cm proximal electrode positioned 3 cm posteriorly to the heart. We modeled the experiment using an ellipsoidal bidomain heart with transmural fiber rotation, placed in a perfusing bath, and subjected to defibrillation shocks delivered by an electrode configuration as described. Our numerical simulations demonstrated VEE occupying a significant portion of the myocardium in the conditions of unequal anisotropy ratios for the intra- and extracellular domains. Statistically significant differences in epicardial polarization patterns were predicted numerically and confirmed experimentally when the interface conditions varied.

CONCLUSION

The present study concludes that VEE are present in transvenous defibrillation. They are shaped by the combined effect of cardiac tissue characteristics and interface conditions. Because of their size, VEE might contribute significantly to defibrillation outcome.

Influence of anisotropy on local and global measures of potential gradient in computer models of defibrillation

A heart-torso model including fiber orientation is used to calculate electric field strength in an active-can transvenous defibrillation system and estimate errors due to inadequate description of the anisotropy of the myocardium. Using a minimum potential gradient (5 V/cm) in a critical mass (95%) of the tissue, the estimated defibrillation voltage threshold for a right ventricular transvenous lead placement differs by only 4.5% when using isotropic myocardial conductivity compared to a model with realistic fiber architecture. In addition, pointwise comparisons of the two solutions reveal differences of 10.8% rms in potential gradient strength and 31.6% rms in current density magnitude in the myocardium, resulting in a change in the location of the low gradient regions. These results suggest that if a minimum potential gradient throughout the heart is necessary to avoid reinitiation of fibrillatory wave fronts, then isotropic models are adequate for modeling the electric field in the heart. Alternatively, the model demonstrates the use of physiologically based descriptions of anisotropy and fiber orientation, which will soon allow simulations of shock induced membrane polarization during defibrillation.

Different phenotypes among slow/beta myosin heavy chain-containing fibres of rabbit masseter muscle: a novel type of diversity in adult muscle

Difference in the phenotype of different mammalian muscle fibres are usually attributed to differences in the expression of the product of different myosin heavy chain (MyHC) genes, which are known as isoforms. We studied differences in phenotype among fibres containing a single MyHC isoform (slow/beta) of the masseter muscle of adult rabbits. Four different monoclonal antibodies to slow/beta MyHC were used to stain serial sections from muscles in males and females. All antibodies recognize a single band on immunoblots and stain the same set of fibres in rabbit postcranial muscles. However, differential staining was observed in the masseter muscles. Antibody BA-D5 reacts with the most fibres, antibody A4.951 reacts with a subset of these fibres, and antibody A4.840 reacts with a subset of these fibres, and antibody A4.840 reacts with a subset of A4.951-positive fibres. Antibody S58 reacts only with an even smaller subset of fibres. Even though differential staining using four antibodies might allow for the expression of as many as 15 different staining patterns, or patterns, or phenotypes, only four were observed on > 99% of over 30 000 fibres studied. In females, nearly 40% of the fibres stain exclusively with antibody BA-D5, while in males, fewer than 8% of the fibres express this phenotype. The proportions of fibres of the other phenotypes do not differ so strikingly with gender. We conclude that an epitope diversity exists among muscle fibres in the adult rabbit masseter and that it is not necessarily a consequence of differences in gene expression. We feel that it is a regulated process and that, at least for some phenotypes, this regulation may be hormonally influenced.

Transjugular portosystemic shunts in pediatric patients awaiting liver transplantation

Three pediatric patients from 6 to 11 years of age awaiting liver transplantation for end stage liver disease underwent transjugular intrahepatic portosystemic shunt (TIPS) placement for control of variceal bleeding. Two of the three procedures were performed emergently after endoscopic sclerotherapy failed to stop active bleeding. One procedure was performed electively after multiple prior bleeding episodes. The shunts were created from the middle or left hepatic vein to the left portal vein, and none of the subsequent transplant surgeries was complicated by the presence of the stents. No major or minor complications were related to TIPS placement. Two patients underwent concomitant variceal embolization. Bleeding was successfully controlled in each patient. We conclude that TIPS placement in children is technically feasible, does not complicate subsequent surgery, and is useful treating acute variceal hemorrhage in pediatric patients awaiting liver transplantation.

The Effects of Prophylactic Brace Construction Materials on the Reactive Responses of the MCL During Repetitive Impacts

OBJECTIVE

The purpose of the present study was to investigate the effect of different construction materials on the ability of a prophylactic brace to reduce the stresses sustained by a surrogate medial collateral ligament (MCL) under low-energy repetitive impact conditions.

DESIGN AND SETTING

A surrogate leg was fixed at both the hip and foot with the knee in full extension. A prophylactic brace was attached to the surrogate leg and the system struck by an impactor weighing either 6.68 kg or 16.9 kg.

SUBJECTS

A single brace design (Am Pro Knee Guard) was used. Three different materials (nylon, aluminum, graphite) were used in constructing the brace uprights.

MEASUREMENTS

Tension in the MCL was measured under all conditions of brace material and impactor weight. In addition, the impact impulse response of the system was evaluated.

RESULTS

The graphite and aluminum uprights showed significant reductions in both MCL peak tension magnitude (from 12 to 21% improvement) and in the impulse response of the MCL (from 36 to 47% improvement) when compared to the no-brace condition.

CONCLUSIONS

The present study indicates that the choice of brace upright material does have a significant effect on the transmission and absorption of low-level repetitive impact forces at the MCL and should be an important consideration in the design of better knee braces.

Pupil size and reactivity following hydroxypropyl methylcellulose and sodium hyaluronate

AIMS

A prospective randomised clinical trial was set up to compare the effect of hydroxypropyl methylcellulose (Ocucoat) and sodium hyaluronate (Healonid) on pupil size and reactivity following their use in cataract surgery.

METHODS

Pupil measurements were recorded before and 6 weeks after surgery.

RESULTS

There was no significant difference between the two groups with respect to pupil size (p = 0.69, Mann-Whitney U test) nor with respect to reactivity (p = 0.99, Fischer's exact test). Ninety six per cent of the surgery was performed using phacoemulsification.

CONCLUSION

This trial suggests that both viscoelastic materials have similar effects on the pupil after their use in cataract surgery.

Renal tubular leakage complicating microcephalic osteodysplastic primordial dwarfism

We describe a male infant with phenotypic and radiological features of microcephalic osteodysplastic primordial dwarfism type I/III. He showed severe osteoporosis and biochemical derangement owing to renal tubular leakage, which has not previously been reported in this condition. He died aged 5 months.

Mixed allogeneic chimerism and renal allograft tolerance in cynomolgus monkeys

We have developed a nonmyeloablative preparative regimen that can produce mixed chimerism and renal allograft tolerance between MHC-disparate nonhuman primates. The basic regimen includes ATG, nonmyeloablative total-body irradiation (TBI, 300 rads), thymic irradiation (TI, 700 rads), and donor bone marrow infusion. Kidney allografts from MHC-mismatched donors were transplanted with various manipulations of the preparative regimen. Monkeys treated with the basic regimen alone (n = 2) rejected allografts by day 15. With the addition of cyclosporine (CsA) for one month (n = 3), one monkey developed multilineage mixed chimerism and renal allograft tolerance thereafter (> 430 days). To reduce the toxicity of the preparative regimen, TBI was fractionated to 150 rads on two successive days in subsequent studies. All monkeys receiving this modified regimen (n = 4) developed multilineage chimerism with fewer side effects and accepted renal allografts long-term with no further immunosuppression (196 days, 198 days, > 150 days, and > 40 days). In long-term survivors, donor-specific nonreactivity was confirmed by MLR and skin transplantation. Three monkeys treated with the basic regimen plus CsA but with only 150 rads of TBI (n = 1) or no TBI (n = 2) did not develop multilineage chimerism and grafts were rejected (day 40-50) soon after the CsA discontinuation. Monkeys treated with the same regimen, but without DBM (n = 2), rejected kidney allografts by day 52. Therefore, at least transient engraftment of DBM appears to be essential for induction of donor specific tolerance in this monkey model.

Synthesis and metabolism of cysteinyl leukotrienes by the isolated pig kidney

The metabolism and synthesis of cysteinyl leukotrienes by the isolated perfused pig kidney has been investigated. Kidneys were maintained for up to six hours in a recirculating perfusion system by using an oxygenated Krebs-Henseleit buffer containing albumin and the perfluorinated oxygen carrier, FC-43. Perfusion pressure was maintained at 12-13.5 kPa, with perfusion flow rates of 150-250 ml/min resulting in a urine output of between 20-180 ml/hr. Infusion of 3H-LTC4 into the renal artery resulted in rapid and complete metabolism, with the major urinary metabolites comprising LTE4, omega-hydroxy-LTE4, omega-carboxy-LTE4 and N-acetyl-omega-hydroxy-LTE4. The capacity of the isolated kidney to synthesize cysteinyl leukotrienes was monitored by measuring urinary LTE4 excretion; there was a basal urinary excretion of LTE4 (median 43 pg/min, range 8-470 pg/min). Neither lipopolysaccharide or human recombinant tumor necrosis factor alpha had any effect on basal excretion. Treatment with the calcium ionophore A23187, however, resulted in a 38.1 +/- 9.6-fold increase in urinary LTE4 excretion. We conclude that the isolated pig kidney, in the absence of circulating cells, can synthesize cysteinyl leukotrienes in the absence of circulating cells, which can then undergo extensive oxidative metabolism.

Aminophylline toxicity--how many hospital asthma deaths does it cause?

Aminophylline administration was compared in 43 patients who died from asthma and 43 matched controls who were admitted, suffering from acute asthma, to hospitals in the North East Thames Region. A computer program, which used information about individual characteristics, medical history and drug intake, was employed to calculate the serum theophylline levels which were likely to have resulted from the hospital treatment each patient received. Toxic theophylline levels were estimated to have occurred in 21% (9/43) of fatal cases and 7% (3/43) controls. Details of four patients who died when their serum theophylline levels were likely to have been very high are presented. Six fatal cases suffered gastro-intestinal bleeds during their final illness: four of these had theophylline levels which were calculated to have been toxic at the time of bleeding.

Systemic air embolism during laser bronchoscopy

We report a case of massive, fatal, systemic gas embolism which occurred during the course of laser bronchoscopic resection of a bronchial carcinoma. The clinical features of systemic air embolism are discussed.

Controlled investigation of deaths from asthma in hospitals in the North East Thames region

One hundred and thirty deaths definitely or potentially due to asthma occurring in hospitals in the North East Thames region over one year were identified from death certificates and Hospital Activity Analysis records. Thirty five of these deaths were considered after independent assessment to have been directly due to asthma. Control patients who left hospital alive after acute asthma attacks were selected and matched with cases for sex, age, and hospital. Management was compared in the two groups. Inadequate monitoring, including failure to monitor arterial blood gas values, and inadequate use of nebulised beta agonists occurred significantly more often in fatal cases. Use of sedation, inadequate treatment with steroids, exposure to potentially toxic doses of aminophylline, and inadequate clinical assessment were more common in cases than controls, but not significantly so. Failure to institute artificial ventilation contributed to seven deaths. Assessors considered important defects in management to have occurred in 83% (29/35) of the cases and 40% (14/35) of the controls. Nevertheless, most of the hospital deaths (19/35) were considered not to have been preventable. Eight other deaths in the region were attributed to the complications of asthma or its treatment. Three of these were associated with gastrointestinal bleeding and one with perforation of a duodenal ulcer. Before considering policies aimed at speeding admission to hospital of patients with acute attacks of asthma it is crucial that the general standard of hospital care offered to all patients with asthma should be improved.