Biochemical characteristics and clinical manifestation of normocalcemic primary hyperparathyroidism.

BACKGROUND: Normocalcemic primary hyperparathyroidism (nPHPT) is a condition characterized by persistently high levels of parathyroid hormone (PTH) and normal serum calcium levels in the absence of other causes for secondary hyperparathyroidism. The aim of the present study was to assess the clinical presentation and the biochemical characteristics in patients with nPHPT and to compare them with those in patients with hypercalcemic PHPT (hPHPT). MATERIALS AND METHODS: The study included 316 patients (277 women and 39 men, average age 58.7 ± 12.1) diagnosed with PHPT. Total serum calcium, inorganic phosphates (PO4), PTH, urinary Ca (uCa), albumin, creatinine, 25(OH)D and bone markers (b-CTX and ALP) were examined in all of them. BMD of the lumbar spine (LS), distal third of the radius (DR), femoral neck (FN) and total proximal femur (TF) were measured by a dual-energy X-ray absorptiometry (DXA). The patients were divided into two groups according to albumin-corrected calcium (Ca) level - with hPHPT (Ca>2.62 mmol/L) and with nPHPT (Ca 2.12-2.62 mmol/l), without other causes for secondary hyperparathyroidism. RESULTS: The frequency of nPHPT was 15.2%. Normocalcemic patients had lower levels of PTH, higher PO4 and 25(OH)D, and smaller parathyroid adenomas. No significant difference in the frequency of osteoporosis, low-energy fractures, nephrolithiasis and gastrointestinal disorders was found between nPHPT and hPHPT. There was no difference in BMD between the two groups. CONCLUSION: The patients with nPHPT show a more favorable biochemical profile compared to those with hPHPT. Nevertheless, clinical manifestations and complications are similar, without a significant difference in the frequency of osteoporosis, nephrolithiasis, gastrointestinal disorders and low-energy fractures.

Chronic obstructive pulmonary disease exacerbations and progression in relation to ambient air pollutants exposure.

BACKGROUND: The information for the impact of air pollutants on the severity of chronic obstructive pulmonary disease (COPD) and hospital admissions in Bulgaria is scarce. The aim of the study is to assess the relationship between some ambient air pollution and exacerbations levels as well as hospital admissions of patients with COPD in Bulgaria. METHODS: A multi-center, prospective, one-year observational study was conducted among 426 COPD patients. Data from pollution monitoring are collected from the Executive Environment Agency (EEA). RESULTS: The results showed that the pollution with sulfur dioxide (SO2) is less than limit concentrations recommended by the European Union and World Health Organization (WHO), while the pollution with PM exceeds limits values of WHO two times. The mean rate of exacerbations in selected towns are between 0.5-3, the number of exacerbations with hospitalization are between 0.2-1.8 and length of hospital stay is between 1-14 days. CONCLUSIONS: The study confirms that air pollution leads to increased number of exacerbations and hospital stay. The patients with mild level of COPD have 0.86 exacerbations and 2.61 days in hospital per year, while in case of very severe COPD these values increase 4 times. Outside pollutions lead to worsening of the disease severity and hospitalizations due to a higher rate of COPD exacerbations.

Diagnostic Significance of Biomarkers of Iron Deficiency for Anemia in Clinical Practice.

AIM: Iron deficiency anemia (IDA) is a common medical condition, yet there is still some diagnostic uncertainty in this respect. The aim of this study was to compare the clinical significance of biomarkers of iron deficiency (ID) in diagnosing IDA and iron-deficient erythropoiesis in anemic patients. MATERIALS AND METHODS: A total of 103 untreated patients with non-hemolytic anemia were included. Blood count, reticulocyte hemoglobin content (CHr), iron, transferrin saturation (TSAT), ferritin (Ferr), soluble transferrin receptor (sTfR) and sTfR/logFerr index (sTfR-F index) were determined in the patients. RESULTS: TSAT<16% diagnosed 79 patients with IDA (76.6%), Ferr<30 µg/l - 50 patients with IDA (48.5%). Thomas-plot analysis found 76 patients with ID (73.8%) and 56 of them were with iron-restricted erythropoiesis and IDA (54.4%). Biomarkers of ID were significantly different in anemic patients with iron-deficient erythropoiesis (CHr<28 pg) compared with patients with normal hemoglobinisation (p<0.001). With regard to the predictive value of the parameters of ID for iron-deficient erythropoiesis in anemia, their mutually controlled influence proved sTfR-F index only as independent statistically significant (p=0.011). The optimal cut-off value of sTfR-F index from the ROC curve analysis for detecting iron-deficient erythropoiesis in anemia (CHr<28 pg) was 1.35, with sensitivity of 82.1% and specificity of 80.9% (AUC 0.866; p<0.001). CONCLUSIONS: Diagnosis of IDA depends on the applied biomarkers of ID, and TSAT or ferritin when used alone may lead to diagnostic difficulties. Combining sTfR-F index and CHr to evaluate iron-deficient erythropoiesis in patients with anemia in addition to ferritin and TSAT could contribute to improving the diagnosis of IDA in clinical practice.

Cognitive Impairment and Affective Disorders in Patients With Obstructive Sleep Apnea Syndrome.

Sleep-related breathing disorders could be accompanied by or caused by a variety of medical conditions. They are considered to be a significant medical and social problem. Together with excessive daytime sleepiness, patients with obstructive sleep apnea experience neuropsychological symptoms such as anxiety, attention deficits, cognitive impairment, depressive symptoms and other psychological disturbances leading to social adjustment difficulties. Patients diagnosed with obstructive sleep apnea demonstrate a decline in a wide spectrum of cognitive abilities, including memory, attention, psychomotor speed, executive, verbal and visual-spatial skills. The aim of this study is to investigate the cognitive functioning and affective disorders among patients with obstructive sleep apnea syndrome and to examine the frequency and severity of cases in comparison with a control group consisting of healthy volunteers. Our research has shown that there is a relation between sleep apnea and cognitive impairments and affective changes. This relation can be explained by the direct effect of the syndrome on the patient, where the main connecting factor is the severity and the distribution of excessive daytime sleepiness. Along with treatment of the somatic medical condition, it is extremely important that the patient's mental state is treated as well. Trial Registration: 57/2013, Medical University - Sofia, Bulgaria.

Pericardial Effusion in Obstructive Sleep Apnea without Pulmonary Arterial Hypertension and Daily Hypoxemia - is it Unusual?

Background: Pericardial effusion in chronic hypoxemic lung diseases, such as Obstructive Sleep Apnea syndrome, usually occurs after the development of severe pulmonary arterial hypertension. However, data about the frequency of pericardial effusions in Obstructive Sleep Apnea syndrome without pulmonary arterial hypertension and/or daytime hypoxemia are still scarce, and their pathogenesis is unclear. Aims: To assess the prevalence of pericardial effusions and their volume and location in patients with obesity and Obstructive Sleep Apnea syndrome without pulmonary arterial hypertension and/or hypoxemia. Study Design: Cross-sectional study. Methods: We included 279 consecutive patients (162 males) with newly diagnosed Obstructive Sleep Apnea syndrome having a mean age of 42.8±12.4 years and a mean body mass index of 37.3±7.8 kg/m2. Obstructive Sleep Apnea syndrome was confirmed by polysomnography. Main exclusion criteria were concomitant inflammatory diseases, thyroid dysfunction, daytime hypoxemia, nephrotic syndrome, left ventricular systolic dysfunction and pulmonary arterial hypertension. Results: Pericardial effusion was found in 102 (36.56%) -all of them with moderate to severe obstructive Sleep Apnea syndrome. The mean effusion volume was mild to moderate (up to 250 mL). In 36 patients (35.3%) the pericardial effusion was diffuse, in 42 (41.2%), the pericardial effusion was located in front of the right atrium and the right ventricle, and in 24 (23.5%) the pericardial effusion was situated in front of the right cardiac cavities and the left atrium. We found a significant positive correlation between the presence of pericardial effusion and apnea-hypopnea index (r=0.374, p<0.001), body mass index (r=0.473, p<0.001), and desaturation time during sleep (r=0.289, p<0.001). Conclusion: Pericardial effusion in patients with obesity and moderate to severe Obstructive Sleep Apnea syndrome without daily hypoxemia and/or pulmonary hypertension is a relatively common finding. The occurrence of pericardial effusions is dependent mostly on the grade of Obstructive Sleep Apnea syndrome, degree of obesity, and duration of sleep desaturation.

Assessment of the expectancy, seriousness and severity of adverse drug reactions reported for chronic obstructive pulmonary disease therapy.

INTRODUCTION: Adverse drug reactions can cause increased morbidity and mortality, and therefore information needs to be studied systematically. Little is known about the adverse drug reactions for chronic obstructive pulmonary disease therapy. The goal of this study is to assess the expectedness, seriousness and severity of adverse drug reactions during chronic obstructive pulmonary disease therapy based on their reporting in the national pharmacovigilance system. METHODS: This was a prospective, observational, 1-year, real-life study about the pharmacotherapy of a sample of 390 chronic obstructive pulmonary disease patients. Prescribed medicines were systematized and national pharmacovigilance databases were searched for reported adverse drug reactions. The expectedness was evaluated through the review of the summary of product characteristics, the seriousness was evaluated by the clinicians based on the life threatening nature of the adverse drug reactions, and the severity was evaluated through Hartwig's Severity Assessment Scale. Descriptive statistics of the reported adverse drug reactions was performed and the relative risk of developing an adverse drug reaction with all international non-proprietary names included in the analysis was calculated. RESULTS: Results confirm that the chronic obstructive pulmonary disease is a disease with high appearance of adverse drug reactions, and causes many additional costs to the healthcare system. Unexpected and severe adverse drug reactions are frequent. A total of 4.8% of adverse drug reactions were evaluated as life threatening. Majority of adverse drug reactions are classified in Levels 1 (32.6%), 2 (26.4%) and 3 (19%) according to Hartwig's Severity Assessment Scale. Approximately 22% of reported adverse drug reactions affect people's everyday life to a greater extent and require additional therapy which might further increase the risk. The relative risk of developing an adverse drug reaction was highest for novphyllin (relative risk = 0.65), followed by aclidinium bromide (relative risk = 0.09). Both indacaterol and salbutamol are with a relative risk of 0.07. CONCLUSION: In conclusion, the medicines for chronic obstructive pulmonary disease cause many serious adverse drug reactions, most of them were unexpected, lacking in the short product characteristics. Appropriate reporting of adverse drug reactions is necessary to decrease the risk of patients and healthcare system.

Clinical characteristics, treatment patterns, and socio-economic burden of COPD in Bulgaria.

BACKGROUND: While the impact of COPD in Western-Europe is known, data from Eastern-Europe is scarce. This study aimed to evaluate clinical characteristics, treatment patterns, and the socio-economic burden of COPD in Eastern-Europe, taking Bulgaria as a reference case. METHODS: A representative sample of Bulgarian patients with COPD was randomly chosen by pulmonologists, based on the following inclusion criteria: COPD diagnosis with at least 1 year of living with COPD, ≥40 years of age, and use of COPD medication. Patient characteristics, treatment, quality-of-life, healthcare resource use, and costs were systematically assessed. RESULTS: A total of 426 COPD patients were enrolled. Approximately 69% were male, 40% had occupational risk factors, 45% had severe and 11% had very severe COPD. Mean CAT scores were 13.80 (GOLD A), 21.80 (GOLD B), 17.35 (GOLD C), and 26.70 (GOLD D). Annual per-patient costs of healthcare utilization were €579. Yearly pharmacotherapy costs were €693. Indirect costs (reduced and lost work productivity) outnumbered direct costs three times. CONCLUSIONS: Bulgaria has relatively high percentages of (very) severe COPD patients, resulting in considerable socio-economic burden. High smoking rates, occupational risk factors, air pollution, and a differential health system may be related to this finding. Eastern-European COPD strategies should focus on prevention, risk-factor awareness, and early detection.

8-isoprostanes and resistin as markers of vascular damage in non-hypersomnolent obstructive sleep apnoea patients.

BACKGROUND: Oxidative stress and inflammation are assumed as the main pathological triggers for vascular damage in hypersomnolent obstructive sleep apnoea (OSA) patients, whereas their exact role in less symptomatic population is currently unknown. AIM: To determine whether oxidative stress (urinary 8-isoprostane concentration) and inflammation (plasma resistin levels) are associated with vascular damage in non-hypersomnolent (Epworth Sleep Score <11) OSA patients. METHODS: A total of 325 consecutive patients have undergone standard polysomnography, and 256 of them were diagnosed with OSA. Excessive daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS). Only 86 patients with ESS <11 participated in the study. The control group was presented by 45 subjects without OSA. Endothelial function was assessed by ultrasonographic measurement of flow-mediated dilatation (FMD). Intima-media thickness (IMT) and ankle-brachial index (ABI) were determined by ultrasonography. Urinary 8-isoprostanes (Cayman Chemical, USA) were measured, applying mass spectrometry. Resistin (RayBio_ Human ResistinCat#:ELH-Resistin-001) plasma levels were detected by ELISA. RESULTS: In patients with OSA, flow-mediated dilatation was significantly lower than in control subjects (4·62% ±1·9) and (7·1% ±2·8), respectively (P: 0·013). The prevalence of plaques in a.carotis communis was higher in OSA (16% versus 4%). The same is observed regarding a.tibialis posterior (81% vs. 29%). The average IMT and ABI in OSA and in the control group were, respectively, (IMT - 800 µm versus. 666 µm); (ABI -1·06 versus 1·20). Urinary isoprostanes were higher in OSA patients (0·091 versus 0·078) and correlated negatively to FMD (r: -0·825, P: 0·00), IMT (r: -0·324, P: 0·003) and ABI (r: -0·226, P: 0·043). No association between resistin and the degree of vascular injury was found. CONCLUSIONS: In comparison with the control group, increased prevalence of endothelial dysfunction and vascular damage was established in OSA patients without excessive daytime sleepiness. Urinary 8-isoprostanes (oxidative stress markers) are closely associated with FMD (endothelial dysfunction), IMT and ABI (vascular damage). Resistin plasma levels correlated neither to FMD, nor to IMT or ABI.

Risk factors for lung diseases after renal transplantation.

BACKGROUND: Lung diseases are one of the major causes of morbidity and mortality after renal transplantation. The aim of the study is to define the risk factors for infectious and noninfectious pulmonary complications in kidney transplant patients. MATERIALS AND METHODS: We prospectively studied 267 patients after renal transplantation. The kidney recipients were followed-up for the development of pulmonary complications for a period of 7 years. Different noninvasive and invasive diagnostic tests were used in cases suspected of lung disease. RESULTS: The risk factors associated with the development of pulmonary complications were diabetes mellitus (odds ratio [OR] = 4.60; P = 0.001), arterial hypertension (OR = 1.95; P = 0.015), living related donor (OR = 2.69; P = 0.004), therapy for acute graft rejection (OR = 2.06; P = 0.038), immunosuppressive regimens that includes mycophenolate (OR = 2.40; P = 0.011), azathioprine (OR = 2.25; P = 0.023), and tacrolimus (OR = 1.83; P = 0.041). The only factor associated with the lower risk of complications was a positive serology test for Cytomegalovirus of the recipient before transplantation (OR = 0.1412; P = 0.001). CONCLUSION: The risk factors can be used to identify patients at increased risk for posttransplant lung diseases. Monitoring of higher-risk patients allow timely diagnosis and early adequate treatment and can reduce the morbidity and mortality after renal transplantation.

Color and brightness encoded in a common L- and M-cone pathway with expansive and compressive nonlinearities.

Lights near 560 nm appear brighter when flickered, whereas lights near 520 or 650 nm appear yellower. Both effects are consistent with signal distortion within the visual pathway--brightness changes at an expansive nonlinearity, and hue shifts at a compressive one. We previously manipulated the distortion products generated by each nonlinearity to extract the temporal properties of stages of the L- and M-cone pathways that signal brightness and color before (early stages) and after (late stages) each nonlinearity. We find that the attenuation characteristics of the early and late stages are virtually identical in both pathways: The early temporal stage acts like a band-pass filter peaking at 10-15 Hz, while the late stage acts like low-pass filter with a cut-off frequency near 3 Hz. We propose a physiologically relevant model that accounts for the filter shapes and incorporates both nonlinearities within a common parvocellular pathway. The shape of the early band-pass filter is consistent with antagonism between center signals and more sluggish and delayed surround signals, while the late filter is consistent with a simple two-stage low-pass filter. Modeling suggests that the brightness change and hue shift are both initially caused by the half-wave rectification and partition of signals into ON and OFF components. However, the hue shift is probably caused by the additional effects of a later nonlinearity that compresses chromatic red and green signals. Plausible sites for the expansive half-wave rectifying nonlinearity are after surround antagonism, possibly from horizontal cells, but the compressive nonlinearity is likely to be after the late filter.

The temporal characteristics of the early and late stages of L- and M-cone pathways that signal brightness.

Flickering 560-nm light appears brighter and less saturated than steady light of the same average intensity. The changes in appearance are consistent with the visual signal's being distorted at some nonlinear site (or sites) within the visual pathway at which new temporal components, not part of the original waveform, are produced. By varying the input stimulus to manipulate these new temporal components--called distortion products--and measuring our observers' sensitivity in detecting them, we derived the temporal attenuation characteristics of the early (prenonlinearity) and late (post-nonlinearity) stages of the L- and M-cone pathway that signals brightness. We found that the early stage acts like a band-pass filter peaking at 10-15 Hz with sensitivity losses at both lower and higher frequencies, whereas the late stage acts like a two-stage low-pass filter with a corner frequency near 3 Hz. Although brightness is often associated with the fast achromatic or luminance pathway, these filter characteristics, and particularly those of the late filter, are consistent with comparable features of the L-M chromatic pathway that produce mainly chromatic distortion products (Petrova, Henning, & Stockman, 2013). A plausible site for the nonlinearity is after surround antagonism from horizontal cells. Modeling suggested the form of the nonlinearity to be initially expansive but possibly with a hard limit at the highest input levels.

The temporal characteristics of the early and late stages of the L- and M-cone pathways that signal color.

Flickering long-wavelength light appears more yellow than steady light of the same average intensity. The hue change is consistent with distortion of the visual signal at some nonlinear site (or sites) that produces temporal components not present in the original stimulus (known as distortion products). We extracted the temporal attenuation characteristics of the early (prenonlinearity) and late (post-nonlinearity) filter stages in the L- and M-cone chromatic pathway by varying the input stimulus to manipulate the distortion products and the measuring of the observers' sensitivity to them. The early, linear, filter stage acts like a band-pass filter peaking at 10-15 Hz with substantial sensitivity losses at both lower and higher frequencies. Its characteristics are consistent with nonlinearity being early in the visual pathway but following surround inhibition. The late stage, in contrast, acts like a low-pass filter with a cutoff frequency around 3 Hz. The response of the early stage speeds up with radiance, but the late stage does not. A plausible site for the nonlinearity, which modelling suggests may be smoothly compressive but with a hard limit at high input levels, is after surround inhibition from the horizontal cells.

Resistin - the link between adipose tissue dysfunction and insulin resistance in patients with obstructive sleep apnea.

BACKGROUND: Resistin is an adipocytokine, associated with obesity and inflammation. Its exact role in insulin resistance and diabetes in the general population is still controversial. The relation between resistin plasma levels, insulin resistance and risk of impaired glucose metabolism in OSA patients has not been investigated. MATERIALS AND METHODS: Plasma levels of resistin were measured in 67 patients with OSA and impaired glucose metabolism. 34,7% (23/67) had diabetes; 40% (27/67) patients had impаired glucose tolerance(IGT); 25,3%(17/67) had normal glucose metabolism (NGM). The association between resistin, BMI, obesity, markers of insulin resistance, oxidative stress and sleep study characteristics was analysed. The different groups of patients were compared in regards to glucometabolic parameters and biomarkers of oxidative stress - isoprostanes and insulin resistance - free fatty acids (FFA). RESULTS: Plasma levels of resistin were higher in patients with diabetes (6,12 ±5,93ng/ml), compared to those with IGT (3,85±2,81ng/ml, p-0,021) and NGM (3,77±3,23, p-0,043). Resistin did not differ between patients with IGT and NGM (p-0,954). In OSA patients with BMI>40 resistin plasma levels correlated neither to the clinical parameters (BMI, IRI, HOMA-I, HbA1C, AHI, desaturation index), nor to the biomarkers of oxidative stress and insulin resistance. Free fatty acids (0,232>0,177mmol/l, p-0,037) were higher in diabetics in comparison to NGM. CONCLUSIONS: Plasma resistin levels in OSA patients with BMI>40 are independent of insulin resistance and are not associated with the parameters, characterising the oxidative stress or severity of OSA. Resistin could be used in a multiple panel of clinical and biomarkers to discern patients with diabetes from those with IGT; in OSA patients with BMI >40 resistin together with HbA1C could discern patients with diabetes from those with NGM. In OSA patients with BMI >40 FFA and HbA1C are useful clinical markers in assessing the risk of dysglycaemia among patients with normal and IGT.

The role of small heat-shock protein αB-crystalline (HspB5) in COPD pathogenesis.

BACKGROUND: αB-crystallin (HspB5) is a chaperone whose role as a marker of innate immunity activation as well as its therapeutic potential have recently been investigated in several inflammatory diseases: multiple sclerosis, myocardial ischemia, and Guillain-Barré syndrome. AIM: The aim of this study is to determine the role of αB-crystallin in chronic obstructive pulmonary disease (COPD) pathogenesis and inflammation. MATERIALS: Plasma levels of αB-crystallin were studied in 163 patients: 52 healthy non-COPD smokers; 20 COPD smokers in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages I-II; 43 COPD smokers in GOLD stages III-IV. Forty-eight patients were diagnosed with acute inflammatory respiratory disease. The plasma levels of αB-crystallin antibodies were determined by an enzyme-linked immunosorbent assay (Calbiochem), and were confirmed with Western blotting. Tissue expression of the protein was compared in three different groups of patients: COPD smokers, COPD nonsmokers, and in patients with age-related emphysema. RESULTS: The mean level of anti-αB-crystallin antibodies in non-COPD smokers was 0.291 nm. In COPD smokers it was 0.352 nm and, in patients with inflammatory lung diseases, 0.433 nm. There was a statistically significant difference between COPD smokers and healthy non-COPD smokers (P = 0.010). The same could be observed comparing the group of patients with acute inflammation and non-COPD healthy smokers (P = 0.007). There was no statistically significant difference between patients with mild/moderate inflammation and those with severe COPD. Tissue detection of the protein showed that it was significantly overexpressed in COPD smokers in comparison to COPD nonsmokers and was only slightly expressed in patients with age-related emphysema. CONCLUSION: αB-crystallin is increased in patients with inflammatory lung diseases. Though unspecific, it could be used in a panel of markers discerning COPD smokers from healthy nonsmokers. As αB-crystallin is a regulator of innate immunity and a therapeutic anti-inflammatory agent, its exact role in COPD pathogenesis and therapy should be explored further.

Obstructive sleep apnea syndrome and depressive symptoms.

A strong body of evidence has emerged over the recent years suggesting a relationship between obstructive sleep apnea (OSA) and depressive symptoms. The frequent co-occurrence of the two conditions makes it necessary that their co-morbidity and the pathogenetic relations between them should be studied in detail. Most of the studies to date have found a significant correlation between depressive symptoms and OSA. The basic pathogenetic mechanisms involved are disturbed neurotransmission, synaptic remodeling and neuronal death (neuroplasticity). Further longitudinal studies are needed to completely elucidate the OSA-depression relationship. Better knowledge of the problem may significantly improve diagnostics and therapeutical options in that group of patients.

Biological applications of quantum dots.

Quantum dots (QDs) are a novel class of inorganic fluorophore which are gaining widespread recognition as a result of their exceptional photophysical properties. They are rapidly being applied to existing and emerging technologies, and could have an important role in many areas. Significant challenges remain, however, which must be understood and more fully defined before they can be widely validated. This review provides on overview of QD technology, covering QD characteristics, synthesis methods, and the applications in which they have been put to use. The influence of synthesis methods on QD characteristics and their subsequent suitability to different applications is discussed, and a broad outline of the technologies into which they have been incorporated is presented, and the relative merits and weaknesses of their incorporation are evaluated. The potential for further development, and inclusion in other technologies is also discussed, and barriers restricting further progress specified, particularly with regard to the poorly understood surface chemistry of QDs, the potential for alteration of function of biological molecules when complexed with QDs, and on a larger scale the significant potential for cytotoxicity both in vitro and in vivo.