[Pseudomonas aeruginosa and hospital-acquired infections]

Pseudomonas aeruginosa is involved in 10% of hospital-acquired infections as well in adults as in children. The origin of the colonization is as well endogenous as exogenous favoured by the water environment or the hand carriage. The adequate use of antibiotics is the main way to prevent hospital-acquired infections due to P. aeruginosa. Indeed, the use of fluoroquinolones is the main risk factor to select multiresistant P. aeruginosa.

The reliability of character recognition: An Australian & New Zealand expert-novice comparison study in the interpretation of chemically recovered serial numbers

The chemical recovery of a defaced serial number is a common forensic science practice, however it is not understood how proficient experts perform in correctly identifying recovered serial numbers. Understanding the accuracy of experts and how they compare to novices in character recognition can help to establish a baseline for this expertise. In this study an expert-novice comparison assessment was completed involving 118 test plates, each stamped with six randomised alphanumeric characters. The plates were defaced and chemically recovered before being viewed by multiple participants over six time intervals. A total of 3169 character inspections were completed. An assessment of confidence and error rates were calculated for both expert (trained) and novice (untrained) participants. Errors were counted when a participant interpreted a different character to that of the ground truth and believed the result was accurate for reporting. The results showed a similar (2.3 % and 2.4 %) error rate for the cohorts, however a statistical difference in confidence levels was recorded, demonstrating the more conservative nature of experts. This study aims to assist in validating practitioner interpretations, through addressing some forensic science criticisms, such as establishing error rates to routine scientific practices.

Understanding power in randomized trials: The example of vertebroplasty

OBJECTIVES

Randomized trials (RCTs) should include a sufficient number of patients to reduce the risk that the observed outcome is a result of chance rather than from a truly different treatment effect. Trials must be even larger to claim an absence of treatment effect in a placebo-controlled trial. To estimate the size of the trial and maximize power, it is often suggested to use a comparison between the means of a continuous variable.

METHODS

We examine the RCTs that have compared vertebroplasty and placebo for patients with osteoporotic fractures. Most trials compared the means of a continuous pain score to yield implausibly small trials, as small as 24 patients per group.

RESULTS

The minimally significant difference between groups has no precise clinical meaning for patients when it is based on a comparison of means of pain scores. A comparison of the proportions of patients reaching a per-patient outcome measure of treatment success is much more pertinent if the trial is to inform the care of future patients. The resulting trials will admittedly need to be larger, but they will be much less likely to fall prey to the 'evidence of absence' fallacy. Furthermore, trial size should also take into consideration harder clinical outcome measures, such as death and disability.

CONCLUSION

When the goal of a trial is to inform outcome-based medical care, comparing the proportions of patients reaching a clinically pertinent outcome is more appropriate than comparing the means of a continuous variable.

[Helicobacter pylori gastric infections in children]

OBJECTIVES

Numerous reports have established the association of Helicobacter pylori and recurrent abdominal pain in children. We investigated the clinical, bacteriological and therapeutic features of our patients seen over a 1 year period.

METHODS

We investigated 121 children during 1992 in Hospital Saint Vincent-de-Paul, Paris. At endoscopy, biopsies were taken and sent for histology and bacteriology and urease testing. A decision regarding treatment by amoxicillin and metronidazol was made after positive results of bacteriology and/or histology.

RESULTS

Heliobacter pylori was found in 47 antral biopsies after pathology examination with Giemsa staining alone 16 times, bacterial culture 9 times and both methods 22 times. Abdominal pain was the prominent symptom, occurring in 35.5% of Helicobacter pylori+patients. In 25 of the positive negative patients, a nodular gastritis was observed (53.1%) and in 27.6% of them a weight loss or a delay in weight gain. Few patients became after combined treatment with amoxicillin and metronidazol whereas eradication rates after triple therapy with amoxicillin-metronidazol and H2 antagonist or proton pump blocker were higher.

CONCLUSION

Helicobacter pylori related gastritis is a common cause of abdominal complaints in children. The most common symptom is recurrent abdominal pain. Antral nodularity is a peculiar endoscopic finding in children. Two-drug therapy associating amoxicillin-metronidazol is often ineffective to eradicate the bacteria whereas eradication rates after triple therapy amoxicillin-metronidazol and H2 antagonist or proton pump blocker are higher.

Intracavernous aneurysms: treatment by proximal balloon occlusion of the internal carotid artery

Seven patients with intracavernous aneurysms were treated by proximal balloon occlusion of the carotid artery, with no attempt to preserve carotid blood flow. After a 15-minute occlusion trial, two balloons were detached proximal to the neck of these aneurysms. Major clinical improvement occurred in six patients and no procedure-related complications were encountered (the follow-up period was 4-14 months). Because these aneurysms arise proximal to major collateral pathways, proximal carotid occlusions via endovascular techniques are simple and safe and carry with them little risk of thromboembolism.

Percutaneous angioplasty of atherosclerotic and postsurgical stenosis of carotid arteries

A technique for safe angioplasty of atherosclerotic stenosis of internal and common carotid arteries is described in which temporary balloon occlusion of the internal carotid artery is used to prevent cerebral embolization during manifestation of ulcerated plaques. Its successful use in six atherosclerotic stenosis is described. Five angioplasties of postsurgical stenoses are also reported in which the technique of temporary occlusion was not used. The future of carotid artery angioplasty is discussed.

Developmental study of rat vestibular neuronal circuits during a spaceflight of 17 days

The aim of this study was to investigate the potential plasticity of the vestibular system, in structural and biochemical terms, at the level of the gravity receptors (the sensory hair cells), the primary neurons relaying the sensory signals (the vestibular ganglion neurons) and their projections into the vestibular nuclei. We studied the biochemical differentiation of the sensory cells and of the vestibular ganglion by investigating which calcium-binding proteins were present. We studied the development of peripheral synaptic connections of the efferent system by investigating the distribution of CGRP (calcitonin-gene related-peptide) and we also studied the cerebellar synaptic connections in the vestibular nuclei, as identified by the presence of calbindin. Putative changes were studied after a 17-day episode of microgravity (Neurolab STS-90), in developing rats between postnatal days 8 and 25. The extent to which these changes could be caused by alterations in gravity was determined by examining sensory and nervous structures not involved in gravity detection, the cochlea and the cochlear nuclei.