Electrical impedance tomography with compensation for electrode positioning variations

Ideally electrical impedance tomography (EIT) should not be oversensitive to electrode positions, but this conflicts with efforts to produce high-resolution images. Two procedures are presented that balance reducing the sensitivity to electrode position errors with generating practicable EIT images. The first provides a criterion based on electrode sensitivity for regularizing the reconstruction through spectral expansion. The main consequences of this are that smoother images are produced and the number of artefacts and their magnitude are generally reduced. The second modification uses the recorded data to compensate for electrode movements that have occurred after the reference data were measured. Image smoothness is used as the criterion for the readjustment. Computer simulation tests have shown that this modification produces improved image fidelity.     

Fatal G-CSF-induced pulmonary toxicity

Inherited thrombophilia has been suggested as a cause of Legg-Calvé-Perthes disease in up to 75% of patients. This prevalence seems high compared to the prevalence of inherited thrombophilia in other thrombotic disorders (average, 30%). Therefore, we investigated 44 patients with Legg-Calvé-Perthes disease for antithrombin-III, protein-C, and protein-S deficiency and activated protein C (APC) resistance. Three (6.8%) of our patients were positive for APC resistance, and one patient (2.2%) showed deficiency of protein-C activity. Our results suggest that inherited thrombophilia is not associated with avascular necrosis of the femoral head (Legg-Calvé-Perthes disease).     

Adenoma characteristics at first colonoscopy as predictors of adenoma recurrence and characteristics at follow-up. The Polyp Prevention Study Group

In Bacillus transformation, sexual isolation is known to be an exponential function of the sequence divergence between donor and recipient. Here, we have investigated the mechanism under which sequence divergence results in sexual isolation. We tested the effect of mismatch repair by comparing a wild-type strain and an isogenic mismatch-repair mutant for the relationship between sexual isolation and sequence divergence. Mismatch repair was shown to contribute to sexual isolation but was responsible for only a small fraction of the sexual isolation observed. Another possible mechanism of sexual isolation is that more divergent recipient and donor DNA strands have greater difficulty forming a heteroduplex because a region of perfect identity between donor and recipient is required for initiation of the heteroduplex. A mathematical model showed that this heteroduplex-resistance mechanism yields an exponential relationship between sexual isolation and sequence divergence. Moreover, this model yields an estimate of the size of the region of perfect identity that is comparable to independent estimates for Escherichia coli. For these reasons, and because all other mechanisms of sexual isolation may be ruled out, we conclude that resistance to heteroduplex formation is predominantly responsible for the exponential relationship between sexual isolation and sequence divergence in Bacillus transformation.     

Informed consent: how much information is enough?

BACKGROUND: Recent judicial decisions involving informed consent have led to some medical practitioners altering the way they obtain consent. The aim of this study was to determine the degree to which patients understood the risks associated with a surgical procedure after giving routine consent and whether providing additional detailed verbal and/or written information improved their understanding. It was further determined whether the provision of more extensive information altered patients' anxiety levels. METHODS: Patients undergoing femoral popliteal bypass or carotid surgery were randomized to obtain either routine consent only or routine consent with verbal or written or verbal and written consent. Patients undertook a pre-operative risk and complication questionnaire, a pre- and postoperative anxiety and depression evaluation and a follow-up questionnaire 6 weeks after discharge. RESULTS: Thirty-two patients were included in the trial. The comprehension questionnaire resulted in a correct percentage response of 48% for the routine information only, 59% with added verbal information, 59% with added written information and 55% with added written and verbal information. Twenty-five per cent of patients stated that they had a poor understanding of the risks and complications of the procedure. CONCLUSIONS: Additional written or verbal information did not improve a patient's understanding of risks and complications of the procedure. It also did not improve patients' perceived understanding of the operation or its complications. Patients' anxiety levels were unaltered by the increase in the information they were given. The information provided to patients should be simple, easy to understand and list any possible major complications to enable the patient to determine whether to undergo or decline a procedure.     

5-HT4 receptor antagonism does not affect motor and reward mechanisms in the rat

5-HT4 receptors are concentrated in areas of the brain which are rich in dopamine neuronal markers, which may suggest that they influence motor and reward processes. We tested this hypothesis by examining the effects of a 5-HT4 receptor antagonist, 8-amino-7-chloro-(N-butyl-4-piperidyl)methylbenzo-1,4-dioxan-5-car boxylate hydrochloride (SB-204070-A) on amphetamine- and nicotine-induced locomotor stimulation in intact rats. In rats with unilateral 6-hydroxydopamine-induced lesions of the ascending nigrostriatal dopaminergic projection, SB-204070-A was tested for its effects on amphetamine-induced rotation. SB-204070-A was also tested for its effects on rewarded behaviour maintained by intracranial self-stimulation. SB-204070-A did not alter behaviour under any of these conditions, suggesting a lack of involvement of the 5-HT4 receptor in motor and reward processes.