Beatty's box

William Beatty, the surgeon aboard the Victory who tended Nelson in his final moments, had an unusual set of surgical instruments, put together to his own specification

Cost-effectiveness of population screening for Helicobacter pylori in preventing gastric cancer and peptic ulcer disease, using simulation

OBJECTIVES

To evaluate the cost-effectiveness of population screening for Helicobacter pylori in preventing gastric cancer and peptic ulcer disease in England and Wales.

METHODS

A discrete event simulation model used parameter estimates, derived from peer-reviewed literature, routine data and statistical modelling. Population screening was compared with no screening but with opportunistic eradication in patients presenting with dyspepsia. Costs included screening, eradication and costs averted to provide costs per life years saved (cost/LYS) for preventing gastric cancer and peptic ulcer disease. Sensitivity analyses were undertaken.

RESULTS

The cost/LYS from screening at age 40 years was Uk pounds 5860 at discount rates of 6%. The outcomes were sensitive to H. pylori prevalence, the degree of opportunistic eradication, the discount rate, the efficacy of eradication on gastric cancer risk, the risk of complicated peptic ulcer disease and gastric cancer associated with H. pylori infection, and the duration of follow-up. In sensitivity analyses, the cost/LYS rarely exceeded UK pounds 20000 over an 80-year follow-up, but did for shorter periods.

CONCLUSIONS

H. pylori screening may be cost-effective in the long term. However, before screening can be recommended further evidence is needed to resolve some of the uncertainties, particularly over the efficacy of eradication on risk of gastric cancer, the risk associated with complicated peptic ulcers, and the effect of more widespread opportunistic testing of patients with dyspepsia.

Cost-effectiveness of population screening for Helicobacter pylori in preventing gastric cancer and peptic ulcer disease, using simulation

OBJECTIVES

To evaluate the cost-effectiveness of population screening for Helicobacter pylori in preventing gastric cancer and peptic ulcer disease in England and Wales.

METHODS

A discrete event simulation model used parameter estimates, derived from peer-reviewed literature, routine data and statistical modelling. Population screening was compared with no screening but with opportunistic eradication in patients presenting with dyspepsia. Costs included screening, eradication and costs averted to provide costs per life years saved (cost/LYS) for preventing gastric cancer and peptic ulcer disease. Sensitivity analyses were undertaken.

RESULTS

The cost/LYS from screening at age 40 years was Uk pounds 5860 at discount rates of 6%. The outcomes were sensitive to H. pylori prevalence, the degree of opportunistic eradication, the discount rate, the efficacy of eradication on gastric cancer risk, the risk of complicated peptic ulcer disease and gastric cancer associated with H. pylori infection, and the duration of follow-up. In sensitivity analyses, the cost/LYS rarely exceeded UK pounds 20000 over an 80-year follow-up, but did for shorter periods.

CONCLUSIONS

H. pylori screening may be cost-effective in the long term. However, before screening can be recommended further evidence is needed to resolve some of the uncertainties, particularly over the efficacy of eradication on risk of gastric cancer, the risk associated with complicated peptic ulcers, and the effect of more widespread opportunistic testing of patients with dyspepsia.

Decontamination of pork carcasses during scalding and the prevention of Salmonella cross-contamination

AIMS

The objective of this study was to establish critical temperature limits to prevent cross-contamination of pork carcasses during scalding.

METHODS AND RESULTS

Mixtures of antibiotic-resistant mutants of Salmonella species were heat treated at 50, 55 and 60 degrees C in samples of commercial scald tank water. Surviving cell numbers were estimated by plating treated suspensions on (i). tryptone soya agar (TSA) and (ii). on TSA, overlaid with brilliant green agar plus nalidixic acid and streptomycin sulphate and used to estimate D-values for the treated mixed cell suspensions.

CONCLUSIONS

A time-temperature combination of 1.4 min at 60 degrees C is required to achieve a 1 log reduction in Salmonella in scald tank water. The predicted equivalent at 65 degrees C is 0.18 min.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides data and a model to enable pork processors to identify and apply processing parameters to limit the risks of transfer of Salmonella between pig carcasses during commercial scalding operations.

Warm or cold contrast medium in the micturating cystourethrogram (MCUG): which is best?

AIM

The purpose of this study was to determine what difference using room temperature ("cold") or body temperature ("warm") contrast medium had on the outcome of MCUG examinations in infants under 1 year of age.

MATERIALS AND METHODS

One hundred infants (50 males and 50 females) referred for an MCUG were identified. Individuals with known bladder neuropathy were excluded. Each was randomized to receive either warm or cold contrast medium. The screening time, volume of contrast instilled, number of attempts at voiding, patient distress, completeness of bladder emptying and incidence of reflux were measured and the results between the two groups compared.

RESULTS

No difference was found between the two groups with regards to screening time, volume of contrast instilled or number of attempts at voiding. There was a statistically significant (p<0.05, chi square) difference in distress levels, with more children crying during instillation of cold contrast medium than warm. Bladder emptying was more often to completion when using cold contrast medium (32 compared with 16%), and vesicoureteric reflux (VUR) was more commonly demonstrated when using warm contrast medium (16 compared with 6%), although these values did not reach statistical significance.

CONCLUSION

Warm contrast medium causes significantly less distress than cold contrast medium, but does not prolong screening time or increase the volume of contrast required.

Isoflurane antagonizes the capacity of flurothyl or 1,2-dichlorohexafluorocyclobutane to impair fear conditioning to context and tone

In animals, the conventional inhaled anesthetic, isoflurane, impairs learning fear to context and fear to tone, doing so at concentrations that produce amnesia in humans. Nonimmobilizers are inhaled compounds that do not produce immobility in response to noxious stimulation, nor do they decrease the requirement for conventional inhaled anesthetics. Like isoflurane, the nonimmobilizer 1,2-dichlorohexafluorocyclobutane (2N) impairs learning at concentrations less than those predicted from its lipophilicity to produce anesthesia. The capacity of the nonimmobilizer di-(2,2,2,-trifluoroethyl) ether (flurothyl) to affect learning and memory has not been studied. Both nonimmobilizers can cause convulsions. We hypothesized that if isoflurane, 2N, and flurothyl act by the same mechanism to impair learning and memory, their effects should be additive. We found that isoflurane, 2N, and flurothyl (each, alone) impaired learning fear to context and fear to tone in rats, with the nonimmobilizers doing so at concentrations less than those that cause convulsions. (Fear was defined by freezing [volitional immobility] in the presence of the conditioned stimulus [context or tone].) However, the combination of isoflurane and 2N or flurothyl produced an antagonistic rather than an additive effect on learning, a finding in conflict with our hypothesis. And flurothyl was no less potent than 2N (at least no less potent relative to the concentration of each that produced convulsions) in its capacity to impair learning. We conclude that conventional inhaled anesthetics and nonimmobilizers impair learning and memory by different mechanisms. The basis for this impairment remains unknown.

IMPLICATIONS

Conventional inhaled anesthetics and nonimmobilizers are antagonistic in their effects on learning and memory, and this finding suggests that they impair learning and memory, at least in part, by different mechanisms.

The changing attitudes of health professionals and consumers towards a coordinated care trial--SA HealthPlus

The national coordinated care trials have been a vehicle for health reform in Australia, driven by escalating health care costs and projections of an ageing population. The first round of trials conducted between 1997 and 1999 set the trials a challenge to reduce financial and system barriers to enable health professionals in all sectors and consumers to develop service delivery models which would give better outcomes for patients within existing resources. As part of a change management strategy, the developers of the SA HealthPlus trial assessed the attitudes of health professionals and consumers involved in designing the projects which made up the larger trial, prior to trial development and twelve months later. This paper reports on the results of the survey and how initial enthusiasm gave way to appropriate anxiety as the complexities of creating a new system of care from reactive to prospective patient centred care planning, became a reality. The survey enabled trial developers to show evidence of acceptability for the new model of care and identify areas of concern and appropriate strategies for the project teams. This type of survey and the issues identified may be of benefit to the second round coordinated care trials and health regions aiming to initiate coordinated care programs.

Tooth brushing-induced seizures: a case report

We report a 28-year-old woman of normal intellect, who had three late-onset seizures with unusual ictal features and secondary generalization during prolonged and vigorous tooth brushing. Neurologic examination and brain magnetic resonance imaging (MRI) were normal, but interictal EEG showed left frontal epileptiform activity. Reasonable precautions (regular but briefer and less vigorous brushing of her teeth) combined with a moderate dose of carbamazepine effectively prevented seizure recurrence. This case may be an example of cryptogenic form of reflex epilepsy with seizures induced exclusively by tooth brushing.

On the cause of mental retardation in Down syndrome: extrapolation from full and segmental trisomy 16 mouse models

Down syndrome (DS, trisomy 21, Ts21) is the most common known cause of mental retardation. In vivo structural brain imaging in young DS adults, and post-mortem studies, indicate a normal brain size after correction for height, and the absence of neuropathology. Functional imaging with positron emission tomography (PET) shows normal brain glucose metabolism, but fewer significant correlations between metabolic rates in different brain regions than in controls, suggesting reduced functional connections between brain circuit elements. Cultured neurons from Ts21 fetuses and from fetuses of an animal model for DS, the trisomy 16 (Ts16) mouse, do not differ from controls with regard to passive electrical membrane properties, including resting potential and membrane resistance. On the other hand, the trisomic neurons demonstrate abnormal active electrical and biochemical properties (duration of action potential and its rates of depolarization and repolarization, altered kinetics of active Na(+), Ca(2+) and K(+) currents, altered membrane densities of Na(+) and Ca(2+) channels). Another animal model, the adult segmental trisomy 16 mouse (Ts65Dn), demonstrates reduced long-term potentiation and increased long-term depression (models for learning and memory related to synaptic plasticity) in the CA1 region of the hippocampus. Evidence suggests that the abnormalities in the trisomy mouse models are related to defective signal transduction pathways involving the phosphoinositide cycle, protein kinase A and protein kinase C. The phenotypes of DS and its mouse models do not involve abnormal gene products due to mutations or deletions, but result from altered expression of genes on human chromosome 21 or mouse chromosome 16, respectively. To the extent that the defects in signal transduction and in active electrical properties, including synaptic plasticity, that are found in the Ts16 and Ts65Dn mouse models, are found in the brain of DS subjects, we postulate that mental retardation in DS results from such abnormalities. Changes in timing and synaptic interaction between neurons during development can lead to less than optimal functioning of neural circuitry and signaling then and in later life.

A randomized controlled trial of the effects of multi-sensory stimulation (MSS) for people with dementia

OBJECTIVES

To investigate short-term effects of Multi-Sensory Stimulation (MSS) on behaviour, mood and cognition of older adults with dementia, the generalization of effects to day hospital and home environments and the endurance of any effects over time.

DESIGN

A randomized controlled trial comparing MSS with a credible control of one-to-one activities.

METHODS

Fifty patients with diagnoses of moderate to severe dementia were randomized to either MSS or Activity groups. Patients participated in eight 30-minute sessions over a 4-week period. Ratings of behaviour and mood were taken before, during and after sessions to investigate immediate effects. Pre, mid, post-trial, and follow-up assessments were taken to investigate any generalization of effects on cognition, behaviour at the day hospital and behaviour and mood at home and endurance of effects once sessions had ceased.

RESULTS

Immediately after MSS and Activity sessions patients talked more spontaneously, related better to others, did more from their own initiative, were less bored/inactive, and were more happy, active or alert. Both groups were more attentive to their environment than before, with a significantly greater improvement from the MSS group. At the day hospital, patients in the Activity group improved on their 'speech skills' (amount of speech; initiation of speech), whereas the MSS group remained unchanged during the trial. The MSS group showed a significant improvement in mood and behaviour at home compared to the Activity group whose behaviour deteriorated. No longer-term benefits were shown; indeed, behaviour declined sharply during the month follow-up period.

CONCLUSIONS

Both MSS and Activity sessions appear to be effective and appropriate therapies for people with dementia.

A single-center experience with 1,378 CarboMedics mechanical valve implants

BACKGROUND

The CarboMedics bileaflet prosthetic heart valve was introduced in 1986. We first implanted it in March 1991. The purpose of this study was to analyze our clinical experience with this valve.

METHODS

Between March 1991 and December 1997, 1,378 valves were implanted in 1,247 patients, 705 men (56.5%) and 542 (43.5%) women with a mean age of 62 +/- 11.9 years (+/- the standard deviation). Follow-up is 99% complete and totals 3,978 patient-years.

RESULTS

The early mortality rate was 4.4% (55/1,247). The survival rates at 1 year and 5 years were 91.8% +/- 0.8% (+/- the standard error of mean) (n = 1,062) and 79.2% +/- 1.4% (n = 281), respectively. Freedom from valve-related complications (linearized rate, 4.9% per patient-year) at 1 year and 5 years was 90.6% +/- 0.8% (+/- the standard error of the mean) (n = 996) and 80.6% +/- 1.4% (n = 243), respectively. Linearized rates for various complications were as follows: bleeding events, 1.73% per patient-year; embolic events, 1.76% per patient-year; operated valvular endocarditis, 0.18% per patient-year; valve thrombosis, 0.10% per patient year; and nonstructural dysfunction, 1.21% per patient-year. Freedom from reoperation at 1 year and 5 years was 98.6% +/- 0.3% (+/- the standard error of the mean) (n = 1,070) and 97.7% +/- 0.5% (n = 285), respectively.

CONCLUSIONS

Midterm results demonstrate that the CarboMedics prosthetic heart valve exhibits a low incidence of valve-related complications.

Genetic organization of the Escherichia coli K10 capsule gene cluster: identification and characterization of two conserved regions in group III capsule gene clusters encoding polysaccharide transport functions

Analysis of the Escherichia coli K10 capsule gene cluster identified two regions, regions 1 and 3, conserved between different group III capsule gene clusters. Region 1 encodes homologues of KpsD, KpsM, KpsT, and KpsE proteins, and region 3 encodes homologues of the KpsC and KpsS proteins. An rfaH mutation abolished K10 capsule production, suggesting that expression of the K10 capsule was regulated by RfaH in a manner analogous to group II capsule gene clusters. An IS3 element and a phiR73-like prophage, both of which may have played a role in the acquisition of group III capsule gene clusters, were detected flanking the K10 capsule genes.