Adv Exp Med Biol
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Dengue is a major global disease which, in its severe form, affects up to 500,000 people worldwide each year, most of whom are children. The development of a safe and effective vaccine is a clear priority, together with public health measures to prevent the spread of infection. However, while major epidemics continue to occur, clinicians must also focus on optimising management. ⋯ Very careful titration of fluid therapy is necessary combined with frequent reassessment for signs of worsening shock or the development of fluid overload. In most DSS cases isotonic crystalloid solutions are as effective as colloid solutions, but the question whether early intervention with colloid solutions improves outcome in more advanced shock requires further investigation. The outcome of studies to address this question, together with further research to examine the pathophysiological mechanisms underlying the plasma leakage, will hopefully result in better management of children with severe dengue but may also provide useful insights into other diseases that affect endothelial function.
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Randomized Controlled Trial
The effect of two different intermittent hypoxia protocols on ventilatory responses to hypoxia and carbon dioxide at rest.
Intermittent hypoxia (IH) consists of bouts of hypoxic exposure interspersed with normoxic intervals. The optimal IH regime for increasing the ventilatory response in humans is unknown, although in animals there is evidence that multiple short duration bouts of intermittent hypoxia (SDIH) provoke larger changes in chemosensitivity than longer duration bouts of intermittent hypoxia (LDIH). The purpose of this study was to compare responses to both hypercapnia and hypoxia between the two protocols. ⋯ Following each 7-day IH protocol, mean HVR was significantly (p < 0.05) increased by 67% and 49% (for LDIH and SDIH, respectively). One week post IH, HVR values were not different from pre-values. HCVR was increased significantly by the LDIH protocol by 44.1% (p < 0.01) and remained elevated by 41.5% at 7 days post (p < 0.01). The changes following the SDIH protocol were smaller (20.7% and 13.5%, at 1 and 7 days post IH, respectively) and not significant. The HCVR remained elevated 7 days following IH (26.7%, p < 0.01). In both the hyperoxic and hypoxic modified rebreathing tests, the CO2 sensitivity was unchanged by either intervention. In hypoxia, the CO2 threshold was significantly reduced following both protocols (p < 0.05). LDIH reduced the threshold by 1.60mmHg, whereas following SDIH it was reduced by 1.98mmHg. Under hyperoxic conditions, LDIH reduced the CO2 threshold by 2.06 mmHg, and SDIH caused a reduction of 2.53 mmHg. There were no significant differences between the two IH protocols for any of the above measures. A 7-day intermittent hypoxic protocol consisting of daily 60-minute exposures to normobaric poikilocapnic hypoxia caused increases in HVR and HCVR. This protocol caused a left-shift in the CO2 threshold but no change in CO2 sensitivity by the modified rebreathing protocol. Neither protocol proved superior in effecting these changes in the resting control of breathing.
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Respiratory long-term facilitation (LTF), a prolonged augmentation of respiratory motor output, is induced by intermittent hypoxia in anesthetized or sleeping rats (and humans in limited conditions). Whether such augmentation in the controller response is of physiological benefit in terms of ventilatory stability remains uncertain; its impact on ventilatory stability will be determined to some extent by its effects on CO2 chemoreflex loop gain. ⋯ Whereas a decreased chemoreflex threshold would promote ventilatory stability, increased chemoreflex gain represents a destabilizing influence. Based on these considerations alone, the impact of respiratory LTF on respiratory stability remains unclear.
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We now have more than 30 years of solid, scientific research about Lyme disease, a relatively common, vector-borne illness in parts of the United States and of Europe. Although there is still widespread misunderstanding of and misinformation about the disease among the lay public, its clinical manifestations as well as how to diagnose and to treat it are now well understood. In the vast majority of cases simple treatment with a relatively short course of orally administered antimicrobials results in long-term cure with no adverse sequelae.