Differential effects of high-altitude exposure on markers of oxidative stress, antioxidant capacity, and iron profiles.

High-altitude (HA) exposure may stimulate significant physiological and molecular changes, resulting in HA-related illnesses. HA may impact oxidative stress, antioxidant capacity, and iron homeostasis, yet it is unclear how both repeated exposure and HA acclimatization may modulate such effects. Therefore, we assessed the effects of weeklong repeated daily HA exposure (2,900-5,050 m) in altitude-naïve individuals ( = 21 individuals, 13 females, mean ± SD, 25.

Non-anemic iron deficiency predicts prolonged hospitalisation following surgical aortic valve replacement: a single-centre retrospective study.

Background: Iron deficiency has deleterious effects in patients with cardiopulmonary disease, independent of anemia. Low ferritin has been associated with increased mortality in patients undergoing cardiac surgery, but modern indices of iron deficiency need to be explored in this population.

Methods: We conducted a retrospective single-centre observational study of 250 adults in a UK academic tertiary hospital undergoing median sternotomy for non-emergent isolated aortic valve replacement.

Abnormal whole-body energy metabolism in iron-deficient humans despite preserved skeletal muscle oxidative phosphorylation.

Iron deficiency impairs skeletal muscle metabolism. The underlying mechanisms are incompletely characterised, but animal and human experiments suggest the involvement of signalling pathways co-dependent upon oxygen and iron availability, including the pathway associated with hypoxia-inducible factor (HIF). We performed a prospective, case-control, clinical physiology study to explore the effects of iron deficiency on human metabolism, using exercise as a stressor.

Intravenous iron to treat anaemia following critical care: a multicentre feasibility randomised trial.

Background: Anaemia is common and associated with poor outcomes in survivors of critical illness. However, the optimal treatment strategy is unclear.

Methods: We conducted a multicentre, feasibility RCT to compare either a single dose of ferric carboxymaltose 1000 mg i.

Iron deficiency anaemia in pregnancy: A contemporary review.

Iron deficiency anaemia is a global health problem, which particularly affects pregnant women. Iron deficiency anaemia during pregnancy is associated with increased maternal and perinatal morbidity and mortality. Maternal iron deficiency may also be associated with neurocognitive deficits in infants.

Sir George Johnson FRCP (1818-96), high blood pressure and the continuing altercation about its origins.

New Findings: What is the topic of this review? The review takes a historical approach to examining where in the body it might be possible to identify the most common cause, or causes, of long-term hypertension. It gathers evidence from histology, human and animal physiology, and computational modelling. The burden of decades of controversy is noted.

Intravenous iron and chronic obstructive pulmonary disease: a randomised controlled trial.

Background: Increased iron availability modifies cardiorespiratory function in healthy volunteers and improves exercise capacity and quality of life in patients with heart failure or pulmonary hypertension. We hypothesised that intravenous iron would produce improvements in oxygenation, exercise capacity and quality of life in patients with chronic obstructive pulmonary disease (COPD).

Methods: We performed a randomised, placebo-controlled, double-blind trial in 48 participants with COPD (mean±SD: age 69±8 years, haemoglobin 144.

Iron bioavailability and cardiopulmonary function during ascent to very high altitude.

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Intravenous iron delivers a sustained (8-week) lowering of pulmonary artery pressure during exercise in healthy older humans.

In older individuals, pulmonary artery pressure rises markedly during exercise, probably due in part to increased pulmonary vascular resistance and in part to an increase in left-heart filling pressure. Older individuals also show more marked pulmonary vascular response to hypoxia at rest. Treatment with intravenous iron reduces the rise in pulmonary artery pressure observed during hypoxia.

Intracellular iron deficiency in pulmonary arterial smooth muscle cells induces pulmonary arterial hypertension in mice.

Iron deficiency augments hypoxic pulmonary arterial pressure in healthy individuals and exacerbates pulmonary arterial hypertension (PAH) in patients, even without anemia. Conversely, iron supplementation has been shown to be beneficial in both settings. The mechanisms underlying the effects of iron availability are not known, due to lack of understanding of how cells of the pulmonary vasculature respond to changes in iron levels.

Human hypoxic pulmonary vasoconstriction is unaltered by 8 h of preceding isocapnic hyperoxia.

Exposure to sustained hypoxia of 8 h duration increases the sensitivity of the pulmonary vasculature to acute hypoxia, but it is not known whether exposure to sustained hyperoxia affects human pulmonary vascular control. We hypothesized that exposure to 8 h of hyperoxia would diminish the hypoxic pulmonary vasoconstriction (HPV) that occurs in response to a brief exposure to hypoxia. Eleven healthy volunteers were studied in a crossover protocol with randomization of order.

How Do Antihypertensive Drugs Work? Insights from Studies of the Renal Regulation of Arterial Blood Pressure.

Though antihypertensive drugs have been in use for many decades, the mechanisms by which they act chronically to reduce blood pressure remain unclear. Over long periods, mean arterial blood pressure must match the perfusion pressure necessary for the kidney to achieve its role in eliminating the daily intake of salt and water. It follows that the kidney is the most likely target for the action of most effective antihypertensive agents used chronically in clinical practice today.

Clinical iron deficiency disturbs normal human responses to hypoxia.

Background: Iron bioavailability has been identified as a factor that influences cellular hypoxia sensing, putatively via an action on the hypoxia-inducible factor (HIF) pathway. We therefore hypothesized that clinical iron deficiency would disturb integrated human responses to hypoxia.

Methods: We performed a prospective, controlled, observational study of the effects of iron status on hypoxic pulmonary hypertension.

The pulmonary vasculature--lessons from Tibetans and from rare diseases of oxygen sensing.

What is the topic of this review? This review is principally concerned with results from studies of the pulmonary vasculature in humans, particularly in relation to hypoxia and rare diseases that affect oxygen sensing. What advances does it highlight? This review highlights the degree to which the hypoxia-inducible factor (HIF) transcription system influences human pulmonary vascular responses to hypoxia. Upregulation of the HIF pathway augments hypoxic pulmonary vasoconstriction, while alterations to the pathway found in Tibetans are associated with suppression of the progressive increase in pulmonary artery pressure with sustained hypoxia.

Non-contact measurement of oxygen saturation with an RGB camera.

A novel method (Sophia) is presented to track oxygen saturation changes in a controlled environment using an RGB camera placed approximately 1.5 m away from the subject. The method is evaluated on five healthy volunteers (Fitzpatrick skin phenotypes II, III, and IV) whose oxygen saturations were varied between 80% and 100% in a purpose-built chamber over 40 minutes each.

Exaggerated pulmonary vascular response to acute hypoxia in older men.

What is the central question of this study? Pulmonary arterial pressure is higher in older than younger humans and predicts mortality. It is also increased by acute hypoxia, which causes constriction of the pulmonary vasculature. We asked whether this pulmonary vascular response to hypoxia is greater in older humans.

A cross-sectional study of the prevalence and associations of iron deficiency in a cohort of patients with chronic obstructive pulmonary disease.

Objectives: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Iron deficiency, with or without anaemia, is associated with other chronic conditions, such as congestive heart failure, where it predicts a worse outcome. However, the prevalence of iron deficiency in COPD is unknown.