Host-dependent differences during synergistic infection by Potyviruses with potato virus X

SUMMARY A comparative analysis of the synergistic interaction between PVX and either PVY or TEV potyviruses was performed in Nicotiana benthamiana and N. tabacum plants. In each PVX/potyvirus combination, doubly infected plants developed much more severe symptoms than singly infected ones. However, while PVX accumulation increased in doubly infected N. tabacum plants compared with singly infected plants, the accumulation of PVX did not vary drastically in doubly infected N. benthamiana plants with respect to single infected ones. These findings suggest that the relationship between viral titre enhancement and synergism in PVX/potyvirus infections is host dependent. Since PVX and potyviruses contain suppressors of a plant antiviral defence system mediated by gene silencing, differences observed in the response of these two related hosts to PVX/potyvirus interactions might reflect the effect of these viruses on host specific antiviral defences.

EMG and duration of ventilatory support in children with Guillain-Barre syndrome

RATIONALE

Predicting length of stay in the intensive care unit (ICU) in children with Guillain-Barre syndrome may help decision-making at admission.

MATERIALS AND METHODS

Between 1996 and 2003, we attended to 30 children with Guillain-Barre syndrome who required ventilatory support in ICU. We prospectively collected different variables that could potentially predict prolonged length of stay and ventilatory support in ICU.

CONCLUSION

Using Cox proportional hazard analysis we found that lack of electrical excitability was the best predictor.

Changes in electromyographic results of patients with lumbar radiculopathy: a follow-up study

OBJECTIVE

To assess the neurophysiologic changes in a group of patients with lumbar radiculopathy 5 to 12 months after their first electromyographic examination.

DESIGN

A prospective group of patients with a case definition of lumbar radiculopathy was reassessed between 5 and 12 months after their first clinical, functional, imaging, and neurophysiologic evaluation. Both the lumbar paraspinals (in which the mini-mapping technique was used) and the same lower limb muscles were explored in every patient. Relevant abnormalities were (1) positive sharp waves/fibrillation potentials, (2) polyphasic motor unit potentials, and (3) large-amplitude/long-duration motor unit potentials. Patients were sorted into 5 groups based on the type and distribution of neurophysiologic abnormalities: from 0 (no abnormalities) to 4 (denervation signs in 2 lower limb muscles and paraspinals). Patients' subjective perception of any improvement or worsening of their condition was also recorded.

SETTING

A referral center for neurophysiologic evaluation.

PARTICIPANTS

A consecutive sample of patients (N=91) with a clinical definition of lumbar radiculopathy (lumbar pain radiating down the leg and below the knee) referred for neurophysiologic assessment was selected for an initial clinical, functional, and neurophysiologic evaluation. Patients were called for a second evaluation (between 5 and 12mo). Thirty-eight (42% of the initial sample) were willing/eligible for the second evaluation.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Changes in (1) electromyographic results; (2) patients' subjective perception of pain; and (3) quality of life, based on the Roland-Morris Questionnaire and Medical Outcomes Study 36-Item Short-Form Health Survey scores.

RESULTS

Paraspinal muscles were most frequently affected. Neurophysiologic abnormalities had improved on reassessment. Clinical improvement was more significant for those patients with initially abnormal electromyographic results.

CONCLUSIONS

There was clinical as well as electromyographic improvement in patients with lumbar radiculopathy within the first year of the initial diagnosis.

Tamoxifen inhibits mitochondrial oxidative stress damage induced by copper orthophenanthroline

In this work, we studied the effect of tamoxifen and cyclosporin A on mitochondrial permeability transition caused by addition of the thiol-oxidizing pair Cu²⁺ -orthophenanthroline. The findings indicate that tamoxifen and cyclosporin A circumvent the oxidative membrane damage manifested by matrix Ca²⁺ release, mitochondrial swelling, and transmembrane electrical gradient collapse. Furthermore, it was found that tamoxifen and cyclosporin A prevent the generation of TBARs promoted by Cu²⁺ -orthophenanthroline, as well as the inactivation of the mitochondrial enzyme aconitase and disruption of mDNA. Electrophoretic analysis was unable to demonstrate a cross-linking reaction between membrane proteins. Yet, it was found that Cu²⁺ -orthophenanthroline induced the generation of reactive oxygen species. It is thus plausible that membrane leakiness is due to an oxidative stress injury.

²¹⁰Po in the diet at Seville (Spain) and its contribution to the dose by ingestion

The activity concentrations of (210)Po have been determined in a total of 24 representative diet samples from Seville (south of Spain), inferring from the obtained values the annual intakes of (210)Po by ingestion of the affected population and the corresponding committed effective doses. The annual intakes of (210)Po and, consequently, the corresponding doses of this radionuclide show a high variability in correspondence with the variability in the composition of the analysed samples over time, and their magnitude is comparable with the estimated ones in other regions/countries of the world with similar diet habits (countries where the marine products have a considerable weight in the diets). Committed effective doses by ingestion higher than 0.1 mSv y(-1) have been estimated exclusively for (210)Po, reflecting the importance of this radionuclide and this route of incorporation in the magnitude of the total doses received by the affected population from natural sources.