P1909Cryobaloon pulmonary vein isolation without pulmonary venography

Introduction

Cryoballoon pulmonary vein isolation (PVI) has been shown to be non-inferior to radiofrequency PVI and have several advantages including shorter procedure times. Cryoballoon PVI traditionally requires the use of occlusive pulmonary venography to assess for balloon position and contact however, some patients have contraindications to the use of iodinated radiocontrast.

Purpose

We assessed the feasibility of performing cryoballoon PVI without pulmonary venography.

Methods

Thirty-five initial consecutive patients with paroxysmal or persistent atrial fibrillation underwent cryoballoon PVI as a primary procedure under conscious sedation by a single operator. None had a contraindication to radiocontrast administration. Left atrial CT was obtained the day prior in all patients to assess pulmonary vein anatomy. Transeptal puncture was performed using 1–5 ml of contrast given the non-routine availability of intracardiac echocardiography. CT images obviated the requirement for pre-balloon deployment venography and pulmonary vein balloon occlusion was assessed by tactile feedback as well as the fluoroscopic appearance of balloon deformation (Fig 1.). If adequate temperature was not obtained with initial cooling during ablation, application was discontinued and the balloon repositioned. If repeated ablation did not result in sufficient cooling and vein isolation, pulmonary venography was utilised to assess adequacy of vein occlusion and sites of leak.

Results

The median age was 57 yrs with 69% male and 63% having paroxysmal AF. 137/138 pulmonary veins were successfully isolated with mean 1.77 ablations per vein. Median nadir ablation temperature was −45°C (range −62 to −30°C) with a median time to isolation of 36.5 seconds. 120/138 (87%) of veins were isolated without the use of contrast, however 18/138 required venography. Overall, 63% of patients had successful PVI without requiring any pulmonary venography. Average procedure time was 104 minutes. One patient sustained a mediastinal hematoma that resolved with conservative management. Median follow up was 3.6 months, with 74% of patients being free from atrial fibrillation at last follow up.

Conclusion

This study demonstrates that it is feasible to perform cryoballoon PVI without pulmonary venography in 87% of targeted veins. In this series, 63% of patients had successful 4 vein isolation without pulmonary vein contrast administration. This technique combined with imaging guided transeptal puncture can allow for truly contrast-less PVI in patients with severe contrast allergy or severe renal dysfunction.

Effectiveness and cost-effectiveness of admissions to women's crisis houses compared with traditional psychiatric wards: pilot patient-preference randomised controlled trial

BACKGROUND

Women's crisis houses have been developed in the UK as a less stigmatising and less institutional alternative to traditional psychiatric wards.

AIMS

To examine the effectiveness and cost-effectiveness of women's crisis houses by first examining the feasibility of a pilot patient-preference randomised controlled trial (PP-RCT) design (ISRCTN20804014).

METHOD

We used a PP-RCT study design to investigate women presenting in crisis needing informal admission. The four study arms were the patient preference arms of women's crisis house or hospital admission, and randomised arms of women's crisis house or hospital admission.

RESULTS

Forty-one women entered the randomised arms of the trial (crisis house n = 19, wards n = 22) and 61 entered the patient-preference arms (crisis house n = 37, ward n = 24). There was no significant difference in outcomes (symptoms, functioning, perceived coercion, stigma, unmet needs or quality of life) or costs for any of the groups (randomised or preference arms), but women who obtained their preferred intervention were more satisfied with treatment.

CONCLUSIONS

Although the sample sizes were too small to allow definite conclusions, the results suggest that when services are able to provide interventions preferred by patients, those patients are more likely to be satisfied with treatment. This pilot study provides some evidence that women's crisis houses are as effective as traditional psychiatric wards, and may be more cost-effective.

Functional variants at the 11q13 risk locus for breast cancer regulate cyclin D1 expression through long-range enhancers

Analysis of 4,405 variants in 89,050 European subjects from 41 case-control studies identified three independent association signals for estrogen-receptor-positive tumors at 11q13. The strongest signal maps to a transcriptional enhancer element in which the G allele of the best candidate causative variant rs554219 increases risk of breast cancer, reduces both binding of ELK4 transcription factor and luciferase activity in reporter assays, and may be associated with low cyclin D1 protein levels in tumors. Another candidate variant, rs78540526, lies in the same enhancer element. Risk association signal 2, rs75915166, creates a GATA3 binding site within a silencer element. Chromatin conformation studies demonstrate that these enhancer and silencer elements interact with each other and with their likely target gene, CCND1.

Molecular neuropathology of MELAS: level of heteroplasmy in individual neurones and evidence of extensive vascular involvement

Mitochondrial DNA (mtDNA) disease is an important genetic cause of neurological disability. A variety of different clinical features are observed and one of the most common phenotypes is MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes). The majority of patients with MELAS have the 3243A>G mtDNA mutation. The neuropathology is dominated by multifocal infarct-like lesions in the posterior cortex, thought to underlie the stroke-like episodes seen in patients. To investigate the relationship between mtDNA mutation load, mitochondrial dysfunction and neuropathological features in MELAS, we studied individual neurones from several brain regions of two individuals with the 3243A>G mutation using dual cytochrome c oxidase (COX) and succinate dehydrogenase (SDH) histochemistry, and Polymerase Chain Reaction Restriction Fragment Lenght Polymorphism (PCR-RFLP) analysis. We found a low number of COX-deficient neurones in all brain regions. There appeared to be no correlation between the threshold level for the 3243A>G mutation to cause COX deficiency within single neurones and the degree of pathology in affected brain regions. The most severe COX deficiency associated with the highest proportion of mutated mtDNA was present in the walls of the leptomeningeal and cortical blood vessels in all brain regions. We conclude that vascular mitochondrial dysfunction is important in the pathogenesis of the stroke-like episodes in MELAS patients. As migraine is a commonly encountered feature in MELAS, we propose that coupling of the vascular mitochondrial dysfunction with cortical spreading depression (CSD) might underlie the selective distribution of ischaemic lesions in the posterior cortex in these patients.

Mitochondrial DNA damage in non-melanoma skin cancer

Mitochondrial DNA (mtDNA) damage, predominantly encompassing point mutations, has been reported in a variety of cancers. Here we present in human skin, the first detailed study of the distribution of multiple forms of mtDNA damage in nonmelanoma skin cancer (NMSC) compared to histologically normal perilesional dermis and epidermis. We present the first entire spectrum of deletions found between different types of skin tumours and perilesional skin. In addition, we provide the first quantitative data for the incidence of the common deletion as well as the first report of specific tandem duplications in tumours from any tissue. Importantly, this work shows that there are clear differences in the distribution of deletions between the tumour and the histologically normal perilesional skin. Furthermore, DNA sequencing of four mutation 'hotspot' regions of the mitochondrial genome identified a previously unreported somatic heteroplasmic mutation in an SCC patient. In addition, 81 unreported and reported homoplasmic single base changes were identified in the other NMSC patients. Unlike the distribution of deletions and the heteroplasmic mutation, these homoplasmic mutations were present in both tumour and perilesional skin, which suggests that for some genetic studies the traditional use of histologically normal perilesional skin from NMSC patients may be limited. Currently, it is unclear whether mtDNA damage has a direct link to skin cancer or it may simply reflect an underlying nuclear DNA instability.

Sites of phosphorylation in tau and factors affecting their regulation

The microtubule-associated protein, tau, is the principal component of paired helical filaments (PHFs) in Alzheimer's disease. PHF-tau is highly phosphorylated and a total of 25 sites of phosphorylation have so far been identified. Many of these sites are serine or threonine residues that are immediately followed in the sequence by proline residues, and hence are candidate phosphorylation sites for proline-directed kinases. In vitro, glycogen synthase kinase-3 (GSK-3), extracellular signal-related kinase-1 and -2, and mitogen-activated protein kinases, p38 kinase and c-jun N-terminal kinase, all phosphorylate many of these sites, although with different efficiencies for particular sites. Phosphorylation studies in transfected cells and neurons show that GSK-3 phosphorylates tau more extensively than do these other proline-directed kinases. Mutations in tau have been shown to affect in vitro phosphorylation of tau by GSK-3. The Arg406-->Trp (R406W) tau mutation also affects tau phosphorylation in cells.

Apolipoprotein E gene and Alzheimer's disease: is tau the link?

The finding that APOE (the gene encoding apolipoprotein E) polymorphic variation was associated with an altered risk of developing Alzheimer's disease (AD) was a significant advance and immediately prompted a search for the mechanisms responsible for this alteration. Some 6 years later, a number of different hypotheses remain that might account for this influence on pathogenesis with no single mechanism being unequivocally accepted. The different approaches to understanding these mechanisms can be broadly categorized as: those suggesting a remote effect, such as different rates of vascular risk factors in those with the different APOE alleles; those proposing altered neuronal vulnerability, perhaps due to apolipoprotein E (ApoE)-isoform-specific differences in local cholesterol transport; and those hypotheses postulating an ApoE interaction with the two key lesions of AD, plaques and tangles. In this chapter we will review the evidence for and against an interaction between ApoE and the neuronal cytoskeleton, in particular with the microtubule-associated protein tau.

Growth phase-associated changes in protein expression in Mycobacterium smegmatis identify a new low molecular weight heat shock protein

De novo protein synthesis and the heat-shock response during different stages of bacterial culture of Mycobacterium smegmatis LR222 were investigated. A discontinuance in the increase in number of colony forming units occurred at mid-exponential phase of growth. This coincided with a plateau in the ATP content of the culture, a reduction in the synthesis of exponential phase proteins (58, 30.5, and 20 kDa), a transitory synthesis of a 32 kDa protein and the induction of stationary-phase proteins (48, 46, 31, 25, and 20 kDa). The response to heat shock showed a growth-phase dependency, with the highest fold-induction of the 75 kDa (DnaK) protein occurring during the transitory cessation in the increase in CFU, while the greatest increase of the 95 kDa, 66 kDa (GroEL), and approximately 17 kDa (a doublet) proteins occurred during stationary phase. The approximately 17 kDa doublet was resolved into four polypeptides by two-dimensional electrophoresis. Mass spectrometric analysis of the sequence of one polypeptide (named Hsp17-2, 16.8 kDa) revealed significant homology to a conserved, 16.2 kDa, hypothetical protein of unknown function in Mycobacterium tuberculosis H37Rv. The increased synthesis of Hsp17-2 in response to heat shock suggests that it may represent a new low molecular weight heat shock protein.

A randomized controlled trial of a community-based consultation service to prevent falls

BACKGROUND

Multifaceted programs that combine assessment with interventions have been shown to reduce subsequent falls in some clinical trials. We tested this approach to see whether it would be effective if offered as a consultation service using existing health care resources.

METHODS

The subjects of this randomized controlled trial had to be aged 65 years or more and had to have fallen within the previous 3 months. They were randomly assigned to receive either usual care or the intervention, which consisted of in-home assessment in conjunction with the development of an individualized treatment plan, including an exercise program for those deemed likely to benefit. The primary outcomes were the proportion of participants who fell and the rate of falling during the following year. Visits to the emergency department and admissions to hospital were secondary outcomes.

RESULTS

One hundred and sixty-three subjects were randomly assigned to either the control or the intervention group, and 152 provided data about their falls. There were no significant differences between the control and intervention groups in the cumulative number of falls (311 v. 241, p = 0.34), having one or more falls (79.2% v. 72.0%, p = 0.30) or in the mean number of falls (4.0 v. 3.2, p = 0.43). Analysis of secondary outcomes (health care use) also showed no significant differences between the intervention group and the control group. In the Cox regression analysis, there was no significant difference between the groups in the proportion of subjects having one or more falls (p = 0.55), but there was a significantly (p < 0.001) longer time between falls in the intervention group. In a post hoc subgroup analysis, subjects with more than 2 falls in the 3 months preceding study entry who had been assigned to the intervention group were less likely to fall (p = 0.046) and had a significantly longer time between falls (p < 0.001), when compared with the group who received usual care.

INTERPRETATION

The intervention did not decrease significantly the cumulative number of falls, the likelihood of participants having at least one fall over the next year or the mean number of falls. It did increase significantly the time between falls in a survival analysis when age, sex and history of falling were used as covariates.

Overexpression of heat-shock proteins reduces survival of Mycobacterium tuberculosis in the chronic phase of infection

Elevated expression of heat-shock proteins (HSPs) can benefit a microbial pathogen struggling to penetrate host defenses during infection, but at the same time might provide a crucial signal alerting the host immune system to its presence. To determine which of these effects predominate, we constructed a mutant strain of Mycobacterium tuberculosis that constitutively overexpresses Hsp70 proteins. Although the mutant was fully virulent in the initial stage of infection, it was significantly impaired in its ability to persist during the subsequent chronic phase. Induction of microbial genes encoding HSPs might provide a novel strategy to boost the immune response of individuals with latent tuberculosis infection.

Biochemical characterization of acyl carrier protein (AcpM) and malonyl-CoA:AcpM transacylase (mtFabD), two major components of Mycobacterium tuberculosis fatty acid synthase II

Malonyl coenzyme A (CoA)-acyl carrier protein (ACP) transacylase (MCAT) is an essential enzyme in the biosynthesis of fatty acids in all bacteria, including Mycobacterium tuberculosis. MCAT catalyzes the transacylation of malonate from malonyl-CoA to activated holo-ACP, to generate malonyl-ACP, which is an elongation substrate in fatty acid biosynthesis. To clarify the roles of the mycobacterial acyl carrier protein (AcpM) and MCAT in fatty acid and mycolic acid biosynthesis, we have cloned, expressed, and purified acpM and mtfabD (malonyl-CoA:AcpM transacylase) from M. tuberculosis. According to the culture conditions used, AcpM was produced in Escherichia coli in two or three different forms: apo-AcpM, holo-AcpM, and palmitoylated-AcpM, as revealed by electrospray mass spectrometry. The mtfabD gene encoding a putative MCAT was used to complement a thermosensitive E. coli fabD mutant. Expression and purification of mtFabD resulted in an active enzyme displaying strong MCAT activity in vitro. Enzymatic studies using different ACP substrates established that holo-AcpM constitutes the preferred substrate for mtFabD. In order to provide further insight into the structure-function relationship of mtFabD, different mutant proteins were generated. All mutations (Q9A, R116A, H194A, Q243A, S91T, and S91A) completely abrogated MCAT activity in vitro, thus underlining the importance of these residues in transacylation. The generation and characterization of the AcpM forms and mtFabD opens the way for further studies relating to fatty acid and mycolic acid biosynthesis to be explored in M. tuberculosis. Since a specific type of FabD is found in mycobacterial species, it represents an attractive new drug target waiting to be exploited.

Trichuris muris: CD4+ T cell-mediated protection in reconstituted SCID mice

Resistance to the murine intestinal nematode Trichuris muris requires the development of a strong Th2 response. In a reconstituted SCID mouse model, CD4+ Th2 cells can mediate resistance to infection in the absence of antibody (Else & Grencis, 1996). The data presented here address the issue of how CD4+ T cells mediate this protective immunity within the SCID host. These studies demonstrate that timing and cell dose are critical if transfer is to result in resistance, with a minimum of 5 x 10(6) immune donor cells required to confer immunity. Furthermore, this CD4-mediated protective immunity only operates against the larval stages of the parasite. When the molecules necessary for activated CD4+ T cell migration to the GALT are inhibited with a cocktail of anti-integrin/addressin antibodies (anti-beta7, anti-MAdCAM-1 and anti-alphaE), the resistance conferred by immune donor cells is completely abrogated. This implies that the effector mechanism acts locally at the level of the gut. CD4+ mediated cytotoxicity, directed against the epithelial cells inhabited by the parasite, could represent a novel, locally acting effector mechanism. However, Fas and Fas ligand-deficient mice, which are unable to mount CD4-mediated cytotoxic responses, readily expel T. muris indicating that the mechanism by which CD4-T cells mediate protective immunity is unlikely to involve killing of infected gut epithelial cells.

European regulatory issues

Current EU regulations do not cover all aspects of the manufacture and control of blood products. Recent legislation coming into force on 1 January 1995 has established the European Medicines Evaluation Agency and introduced revised systems for approving pharmaceutical products, including blood products. There remains a need for comprehensive harmonized legislation covering plasma collection and screening, virus validation studies, and batch release.

Identification of Salmonella typhimurium invasiveness loci

Salmonella typhimurium is capable of entering into (invading) nonphagocytic host cells. To systematically identify the bacterial genes necessary for this process, 15,000 Tn10dCm random transposon mutants of S. typhimurium were individually screened for invasiveness, using the human colonic epithelial Caco-2 cell line. Four hundred and eighty-eight mutants had decreased levels of invasiveness; most were nonmotile. However, five mutants, representing four loci, were completely motile. Further characterization of these five mutants showed that they were also unable to enter the dog kidney epithelial cell line MDCK and the mouse macrophage line J774.A1. In contrast to the parental strain, they were unable to disrupt the transepithelial resistance of polarized epithelial monolayers, nor were they able to penetrate across these epithelial barriers. Three of the four classes of mutants remained virulent in mice. The results confirm several aspects of S. typhimurium invasiveness: (i) intact motility enhances invasiveness of cultured cells; (ii) S. typhimurium invasiveness is multifactorial, and at least six distinct genetic loci are involved; and (iii) invasion loci involved in uptake into epithelial cells are also needed for uptake into cultured phagocytic cells. The results also emphasize that decreased levels of invasiveness eliminate bacterial penetration of polarized epithelial barriers and invasiveness loci mutants are not necessarily avirulent.

Cumulative conception and livebirth rates after in-vitro fertilisation

Cumulative conception and livebirth rates related to age and cause of infertility provide the most useful estimate of success after in-vitro fertilisation (IVF), but limited data are available. It is also uncertain whether the probability of pregnancy, livebirth, and pregnancy failure changes with repeated treatment cycles. To assess the effects of patients' age and cause of infertility on these outcomes, we studied the results of 5055 consecutive IVF cycles (773 clinical pregnancies, 518 livebirths) undertaken on 2735 patients in a single IVF unit. Cumulative conception and livebirth rates were analysed by the life-table approach and differences in rates between age-groups and between causes of infertility were measured by the log-rank test and logistic regression modelling. Both conception and livebirth rates per cycle declined with age (p less than 0.001), and cumulative conception and livebirth rates after five treatment cycles were about 54% and 45%, respectively, at 20-34 years, compared with 38.7% and 28.9% at 35-39 years and 20.2% and 14.4% at greater than or equal to 40 years. The two rates were significantly different between causal groups (p less than 0.001 and p = 0.02, respectively) and were lowest in patients with male infertility or multiple infertility factors. The pregnancy failure rate was higher (p = 0.006) in women over the age of 34 years and there was a significant decline in the chances of pregnancy and livebirth per cycle with successive treatment cycles.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemophilus influenzae lipopolysaccharide disrupts confluent monolayers of bovine brain endothelial cells via a serum-dependent cytotoxic pathway

An in vitro blood-brain barrier (BBB) model consisting of primary cultures of bovine brain microvascular endothelial cells was used to examine the effect of Haemophilus influenzae type b (Hib) on the BBB. Whole bacteria and purified lipopolysaccharide (LPS; greater than 10 ng/ml) caused marked cytotoxicity on the bovine brain endothelial cells. This effect could be completely blocked by polymyxin B. Similar cytotoxic effects were observed with a cultured bovine pulmonary endothelial cell line. Serum was essential for the LPS-mediated cytotoxic effect, and human, horse, bovine, or fetal calf serum all had similar effects. The serum factor was not a complement component. A monoclonal antibody against CD14, a receptor involved in mediating the effect of LPS in monocytes, completely blocked the cytotoxic effect in both brain and pulmonary endothelial cells. These results suggest that Hib LPS disrupts an in vitro BBB model via a serum- and CD14-dependent pathway and that LPS has cytotoxic effects on bovine endothelial cells without the involvement of monocytic cells, an effect that may be important in gram-negative meningitis and in endotoxic shock.

Woven carbon surface replacement in the knee: independent clinical review

An independent assessment was performed of the results of woven carbon implants of mesh or rods into articular cartilage defects performed by two surgeons in the knees of 96 patients. Eight had symptomatic osteochondritis, 31 had chondromalacia patellae and 57 had early osteoarthritis. They were reviewed up to 5 yr after operation. Seventy-six patients (79%) experienced an improvement in analogue pain score and similar improvements occurred in a range of functional activities (P = 0.002). No evidence of inflammatory change or deterioration in joint damage was found. It is concluded that this relatively minor procedure is valuable in younger patients with troublesome symptoms due to early articular cartilage damage and does not prejudice further operative treatment.

Perinatal outcome and congenital malformations in in-vitro fertilization babies from the Bourn-Hallam group

The perinatal outcome and congenital malformations in children born between 1978 and 1987 in Great Britain after in-vitro fertilization (IVF) at Bourn Hall Clinic and the Hallam Medical Centre are presented. The average maternal age was 34.2 years. Multiple births were frequent, constituting 23% of all deliveries; 19% were twins and 4% triplets. There were no quadruplet or higher order multiple births during that period. Twenty-five per cent of all deliveries were preterm. The mean birth weight was 2793 g and was strongly related to multiplicity of pregnancy and gestational age. Overall, 32% of babies had a low birthweight (less than 2500 g) with 6% having a very low birthweight (less than 1500 g). The overall stillbirth and infant mortality rates were two to three times higher than those of infants born after natural conception in England and Wales; this is attributed to the high incidence of multiple births. The stillbirth rates were 5.07, 20.8 and 24.7 per thousand total births in singletons, twins and triplets respectively. The corresponding figures for perinatal mortality were 13.5, 38.2 and 37 per thousand. Overall, 2.5% of the babies had one or more major congenital malformations diagnosed within one week of life. This was within the range of expected values in the United Kingdom and there was no significant increase in any specific malformation.

The influence of training-detraining upon the heart, muscle and adipose tissue of female rats

The purpose of this study was to measure the effects of a 10 week training, 3 week detraining cycle upon heart, muscle and adipose tissue of the rat. Specific pathogen-free female Wistar rats, 175 g at the onset of the experiments, were separated into three treatment groups; Sedentary Control (SC), Trained (T) and Detrained (DT). Animals from the T group were killed at 2, 4, 6, 8 and 10 weeks and animals from the DT group were killed at 7, 14 and 21 days after the last day of training. Unweighted swimming--6 h/day, 5 day/week, was the form of training employed. The animals, after being sacrificed, were anesthetized with nembutal (45 mg/kg body wt.) and muscle samples and heart removed. These tissues were frozen and analyzed at a later date for succinate dehydrogenase (SDH) activity (muscles), total protein (TP), total hydroxylprotein (TH) and wet and dry weight (heart). Adipose tissue was removed last, digested in collagenase (5 mg/ml) and the isolated cells used to measured 2-[3H]deoxyglucose uptake (DOG) and the conversion of D-[1-14C]glucose (C-1) and D-[6-14C]glucose (C-6) to CO2. The results of this study show that 10 weeks of endurance training induced myocardial hypertrophy (P less than 0.05) which involved increases in both TP and TH, the heart of the trained animals having 20.8% more protein and a 28.5% more hydroxlprotein than the sedentary controls. With detraining hypertrophy was lost within 21 days. Training maintained fat cell size at its pre-trained diameter, while inactivity allowed growth in the adipocytes of the control animals. The uptake of DOG and the conversion of glucose C-1 and glucose C-6 to CO2, were significantly (P less than 0.05) higher in the adipocytes of trained animals indicating that they were more responsive to insulin than the sedentary controls, which corresponded to increases in the respiratory enzyme levels of the muscles. During the first 7 days of detraining DOG uptake and both C-1 and C-6 glucose oxidation remained elevated. In conclusion the results of this study clearly demonstrate that there is a direct relationship between adiposity and training that can be related to the insulin responsiveness of the adipose tissue.

Alternative methods of attenuating Salmonella species for potential vaccine use

Because of their invasive properties, Salmonella species are uniquely suited for use as live oral vaccines, and mutants attenuated in general metabolic functions show promise as vaccine strains. We have identified a Salmonella choleraesuis transposon mutant which is deficient in abilities to attach to, invade or penetrate through animal cells. This mutant is avirulent in mice, yet is able to persist within the liver, spleen and gut-associated lymphoid tissue for periods which may be adequate for induction of secretory, humoral and cell-mediated immunity. This and other strains attenuated in factors specifically required for Salmonella pathogenesis may have potential as vaccine strains.

Classification Reliability of Company Financial Performance Models

Many models are in existence that use publicly available company accounting data to construct and weight financial ratios that when aggregated comprise a “z‐score”. This score is used to classify companies as going concerns or bankrupt concerns. These models have generally been very successful in their classification performance. However, ratios can be inherently ill‐conditioned, because dominators can be small relative to particular numerators. Also numerators and denominators can have the wrong sign. When any of these events occur the z‐score is distorted, and therefore the model's classifications unreliable. Examples are given of companies where these phenomena have arisen. It is argued that it is quite common in extant companies. The authors suggest that in such circumstances different models are required to analyse company performance. They suggest that z‐score models ought to be developed where the ratios that comprise the z‐score are naturally bounded, and therefore incapable of displaying such ill conditions.

Surgical management of reflux strictures of the esophagus in childhood

The etiology of gastroesophageal reflux (GER) in infancy is related to developmental factors, and there is a high incidence of associated conditions such as neurologic syndromes and esophageal atresia (60%). This is different from the situation in adults. Experience with 18 consecutive children with peptic esophageal strictures is reviewed to determine if conservative surgical management is effective. Eighteen children 14 months to 13 years (mean 6.3 years) of age took an average of 3.5 years from the time of onset of symptoms of GER to develop tight strictures diagnosed by esophagography and esophagoscopy. The incidence of stricture in patients with GER was approximately 15%. Preoperative dilation or direct surgical management prior to correction of reflux is ineffective. All 18 children were managed by intraoperative dilatation, Nissen fundoplication, and guided dilatation after operation. More aggressive surgical procedures were not required nor were associated operations such as pyloroplasty; they are rarely necessary. An average three-year follow-up indicates that this conservative surgical approach is effective in the management of peptic esophageal strictures in childhood with relief of symptoms and gratifying improvement in growth.