Hypercapnic Chemosensitivity in Patients with Heart Failure: Relation to Shifts in Type-1 Insulin-Like Growth Factor and Sex Hormone-Binding Globulin Levels

In patients suffering from heart failure (HF), autonomic imbalance develops even at early stages along with derangements of cardiopulmonary reflex control and abnormalities in metabolism of several hormones. In 34 men with stable systolic HF, we investigated hypercapnic chemosensitivity (HCS, liter/min·mm Hg) measured using the rebreathing method and defined as the slope of the regression line relating minute ventilation (VE, liter/min) to end­tidal carbon dioxide concentration (PETCO₂ , mm Hg). Serum levels of testosterone, dehydroepiandrosterone sulfate, type­1 insulin­like growth factor (IGF­1), sex hormonebinding globulin (SHBG), estradiol, and cortisol were measured using immunoassays. We found that there were no associations between HCS and clinical variables, applied therapy, and co­morbidities (all P > 0.2). Augmented HCS was accompanied by increased serum SHBG (when expressed in nM, r = 0.43, P < 0.05; when expressed as percentage of the agematched reference values, r = 0.62, P < 0.001) and the reduced serum IGF­1 (when expressed in ng/ml and as percentage of the above­mentioned values, r = –0.49, P < 0.05, and r = = –0.47, P = 0.007, respectively). The HCS was not related to serum levels of all the remaining analyzed hormones (all P > 0.2). Thus, it may be suggested that the hormone stimuli can noticeably modify the reflex mechanisms in cardiorespiratory control in the clinical setting of cardiovascular pathology.У пацієнтів із серцевою недостатністю (СН) навіть на ранніх стадіях захворювання розвивається автономний дисбаланс паралельно з розладами контролю серцево­судинної системи та відхиленнями метаболізму деяких гормонів від норми. Ми досліджували хемочутливість до гіперкапнії (HCS) у 34 чоловіків із СН, використовуючи метод зворотного дихання. Така чутливість визначалась як нахил лінії регресії при співставленні хвилинного об’єму вентиляції (л/хв) та кінцевої концентрації двооксиду вуглецю (мм рт. ст.). Рівні тестостерону, дигідроепіандростерону сульфату, інсулінподібного фактора росту типу 1 (IGF­1), глобуліну, що зв’язує статеві гормони (SHBG), естрадіолу та кортизолу визначали в сироватці крові, використовуючи імунологічні методики. Як виявилося, зв’язки між рівнем HCS, з одного боку, та клінічними показниками, застосованою терапією та супутніми захворюваннями – з другого, були відсутніми (в усіх випадках P > 0.2). Підвищена HCS супроводжувалася підвищеними рівнями SHBG (для концентрацій у наномолях на 1 л r = 0.43, P < 0.05, а для нормованих значень, наведених щодо певної вікової групи, r = 0.62, P < 0.001) та низькими рівнями IGF­1 (для концентрацій у нанограмах на 1 мл та для наведених нормованих значень r = –0.49, P < 0.05 та r = –0.47, P = 0.007 відповідно). Значення HCS не виявляли будь­яких зв’язків з рівнями всіх досліджених гормонів у сироватці. Це дозволяє думати, що гормональні стимули можуть помітно модифікувати рефлекторні механізми контролю серцево­судинної системи у клінічних випадках її патологій

Iron status and survival in diabetic patients with coronary artery disease

Objective-To investigate the impact of iron status on survival in patients with type 2 diabetes and coronary artery disease (CAD). Research Design and Methods-Serum ferritin, transferrin saturation (Tsat), and soluble transferrin receptor (sTfR) were measured in 287 patients with type 2 diabetes and stable CAD (65 ± 9 years of age, 78% men). Results-During a mean follow-up of 45 ± 19 months, there were 59 (21%) deaths and 60 (21%) cardiovascular hospitalizations. Both serum ferritin and sTfR strongly predicted 5-year all-cause mortality rates, independently of other variables (including hemoglobin, measures of renal function, inflammation, and neurohormonal activation). There was an exponential relationship between sTfR and mortality (adjusted hazard ratio [HR] per 1 log mg/L · 4.24 [95% CI 1.43-12.58], P = 0.01), whereas the relationship between ferritin and mortality was U-shaped (for the lowest and the highest quintiles vs. the middle quintile [reference group], respectively: adjusted HR 7.18 [95% CI 2.03-25.46], P = 0.002, and adjusted HR 5.12 [1.48-17.73], P = 0.01). Similar patterns were observed for the composite outcome of all-cause mortality or cardiovascular hospitalization, and in these multivariable models, low Tsat was related to unfavorable outcome. Conclusions-Both low and high serum ferritin (possibly reflecting depleted and excessive iron stores, respectively) along with high serum sTfR (reflecting reduced metabolically available iron) identify patients with type 2 diabetes and CAD who have a poor prognosis. © 2013 by the American Diabetes Association

Resting heart rate variability, attention and attention maintenance in young adults

Heart rate variability (HRV) is a widely used measure that reflects autonomic (parasympathetic) control of the heart. HRV has been linked with attentional performance, but it is unclear to what extent resting HRV is associated with both attention and attentional maintenance. In order to address this, we calculated HRV in seventy-four young and healthy volunteers (43 men, age: 21.6 ± 2.4), who completed the D2 Test of Attention (D2), which was used to calculate an index of Concentration Performance (CP) and a measure of attention maintenance, the coefficient of variation (CV). After accounting for the effects of sex and age on HRV, there was no significant association between HRV and CP (p = .2), but a significant relationship between HRV and CV (p = .03). Overall, our study demonstrates that attention maintenance, but not attentional performance, is associated with higher resting state HRV which suggests that attentional performance from D2 subtest-to-subtest may reflect HRV's facilitation of behaviour flexibility

Iron deficiency: an ominous sign in patients with systolic chronic heart failure

Beyond erythropoiesis, iron is involved in numerous biological processes crucial for maintenance of homeostasis. Patients with chronic heart failure (CHF) are prone to develop iron deficiency (ID), and iron supplementation improves their functional status and quality of life. We sought to examine the relationship between ID and survival in patients with systolic CHF. In a prospective observational study, we evaluated 546 patients with stable systolic CHF [age: 55 +/- 11 (mean +/- standard deviation) years, males: 88%, left ventricular ejection fraction: 26 +/- 7%, New York Heart Association (NYHA) class (I/II/III/IV): 57/221/226/42]. Iron deficiency was defined as: ferritin &lt; 100 mu g/L, or 100-300 mu g/L with transferrin saturation &lt; 20%. The prevalence of ID was 37 +/- 4% [+/- 95% confidence intervals (CI)] in the entire CHF population (32 +/- 4 vs. 57 +/- 10%-in subjects without vs. with anaemia defined as haemoglobin level &lt; 12 g/dL in women and &lt; 13 g/dL in men, P &lt; 0.001). In a multiple logistic model, ID was more prevalent in women, those in the advanced NYHA class, with higher plasma N-terminal pro-type B natriuretic peptide and higher serum high-sensitivity C-reactive protein (all P &lt; 0.05). At the end of follow-up (mean duration: 731 +/- 350 days), there were 153 (28%) deaths and 30 (6%) heart transplantations (HTX). In multivariable models, ID (but not anaemia) was related to an increased risk of death or HTX (adjusted hazard ratio 1.58, 95% CI 1.14-2.17, P &lt; 0.01). In patients with systolic CHF, ID is common and constitutes a strong, independent predictor of unfavourable outcome. Iron supplementation may be considered as a therapeutic approach in these patients to improve prognosis

Radon Treatment Controversy

In spite of long traditions, treatments utilizing radon-rich air or water have not been unequivocally embraced by modern medicine. The objective of this work is to examine factors that contribute to this continuing controversy. While the exact mechanism of radon's effect on human body is not completely understood, recent advances in radiobiology offer new insights into biochemical processes occurring at low-level exposures to ionizing radiation. Medical evidence and patients' testimonials regarding effectiveness of radon spa treatments of various ailments, most notably rheumatoid arthritis are accumulating worldwide. They challenge the premise of the Linear-No-Threshold (LNT) theory that the dose-effect response is the same per unit dose regardless of the total dose. Historically, such inference overshadowed scientific inquiries into the low-dose region and lead to a popular belief that no amount of radiation can be good. Fortunately, the LNT theory, which lacks any scientific basis, did not remain unchallenged. As the reviewed literature suggests, a paradigm shift, reflected in the consideration of hormetic effects at low-doses, is gaining momentum in the scientific community worldwide. The impetus comes from significant evidence of adaptive and stimulatory effects of low-levels of radiation on human immune system