Asthma: the role of low high-density-lipoprotein cholesterol in childhood and adolescence.

BACKGROUND: Several studies have examined the relationship of asthma with serum dyslipidemia and reported positive, negative or no association. Most studies were limited by their cross-sectional design and the wide age range of the participants. In a cohort of children in Cyprus, we explored the association of asthma with serum high-density-lipoprotein cholesterol (HDL-C) at age 16-18 years (follow-up) independently of and in relation to HDL-C at age 11-12 years (baseline). METHODS: In a case-control design, we recruited active asthmatics (AA; n = 68), current wheezers only (CWO; n = 123) and non-asthmatic controls (n = 660). Logistic regression models were used to evaluate associations of asthma with follow-up serum HDL-C and the role of baseline HDL-C. RESULTS: At follow-up, mean HDL-C levels in AA and CWO patients were significantly lower than in the controls (47.9 and 49.7 vs. 53.4 mg/dl; p = 0.001 and p = 0.011). We observed significant associations of AA patients with low HDL-C (<15th percentile; OR 2.32, 95% CI 1.16-4.47) that remained significant after further adjustment for baseline HDL-C (OR 2.14, 95% CI 1.06-4.14). Stratification by baseline HDL-C indicated that the association was significant only in those with high baseline HDL-C (OR 2.40, 95% CI 1.03-5.20). Stratification by IgE sensitization showed that the association was pronounced only in subjects who were sensitized (OR 3.41, 95% CI 1.12-9.88). CONCLUSIONS: Adolescent asthma is associated with low serum HDL-C independent of previous HDL-C levels in childhood. The association appears pronounced in those with a drop in HDL-C levels between childhood and adolescence and in those who have IgE sensitization.

Development of novel LOXL1 genotyping method and evaluation of LOXL1, APOE and MTHFR polymorphisms in exfoliation syndrome/glaucoma in a Greek population.

PURPOSE: In the Greek population of Epirus, exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) occur at a high prevalence. In this study, we validate a novel lysyl oxidase-like 1 (LOXL1) genotyping method, investigate the previously reported association of LOXL1 with XFS/XFG, and evaluate apolipoprotein E (APOE) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms as genetic risk factors for both conditions in our population. METHODS: Blood samples were collected from 82 patients with XFG, 69 patients with XFS, 52 patients with primary open-angle glaucoma (POAG), and 107 controls. APOE and MTHFR 677C>T genotyping was performed from extracted genomic DNA with established methods. A novel methodology of real-time PCR and melting curve analysis was developed and validated to accurately genotype the LOXL1 G153D and R141L polymorphisms by using two different fluorescent channels of the LightCycler instrument (Roche) examining each SNP separately. RESULTS: No significant differences were observed for the APOE and MTHFR polymorphisms between the patients with XFS, the patients with XFG, and the control subjects. The APOE ε2 allele appears to be associated with elevated risk of POAG in our population. Our novel LOXL1 genotyping method was easy to perform, fast, and accurate. A statistically significant association was found for the LOXL1 gene with XFS/XFG in this Greek population. The association of XFS and XFG with G153D appeared to be less powerful in this population (XFS: odds ratio [OR]=2.162, p=0.039, XFG: OR=2.794, p=0.002) compared to other populations, and for R141L, the association was proven only with XFG (OR=3.592, p<0.001). Neither of the two LOXL1 SNPs was significantly associated with POAG. CONCLUSIONS: We confirmed the association between LOXL1 and XFS/XFG, but the APOE and MTHFR polymorphisms are not significant risk factors for the development of XFS/XFG in our population of patients from Epirus (Greece).

The role of procalcitonin and IL-6 in discriminating between septic and non-septic causes of ALI/ARDS: a prospective observational study.

BACKGROUND: The aim was to evaluate the clinical usefulness of a single plasma and bronchoalveolar lavage fluid (BALF) PCT and IL-6 measurement in discriminating septic from non-septic causes of acute respiratory distress syndrome (ARDS) and forecasting clinical outcomes. METHODS: One hundred patients were enrolled within 48 h of ALI/ARDS recognition. Demographic, clinical data, severity indices were recorded and PCT and IL-6 concentrations were measured in plasma and BALF. RESULTS: Plasma PCT and IL-6 values were significantly higher in septic compared to non-septic individuals (p=0.001 and 0.0005, respectively), while there were no differences in their respective BALF values. As far as identification of septic vs. non-septic ARDS is concerned, the comparison of the areas under the curves favored PCT vs. IL-6 [0.88, (95% CI 0.81-0.95) vs. 0.71, (95% CI 0.60-0.81); χ(2)=9.04, p=0.003]. A plasma PCT level of 0.815 ng/mL was associated with 74.1% sensitivity and 97.6% specificity in identifying septic ARDS cases; this corresponded to a diagnostic odds ratio value of 116. Linear regression multivariable analysis disclosed a significant relation of plasma PCT with SOFA score in septic ARDS patients (p<0.001), while neither BALF PCT nor IL-6 levels were associated with clinical outcome. CONCLUSIONS: Early plasma - but not BALF - PCT concentrations can discriminate between septic and non-septic ARDS causes and are associated with the severity of multiple organ dysfunction syndrome in septic ARDS patients. However, neither plasma or BALF IL-6 levels nor BALF PCT levels carry any prognostic potential. A single plasma PCT value higher than 0.815 ng/mL makes a non-septic cause of ARDS highly unlikely.

Nomenclature and basic concepts in automation in the clinical laboratory setting: a practical glossary.

In the early 80s, the word automation was used in the clinical laboratory setting referring only to analyzers. But in late 80s and afterwards, automation found its way into all aspects of the diagnostic process, embracing not only the analytical but also the pre- and post-analytical phase. While laboratories in the eastern world, mainly Japan, paved the way for laboratory automation, US and European laboratories soon realized the benefits and were quick to follow. Clearly, automation and robotics will be a key survival tool in a very competitive and cost-concious healthcare market. What sets automation technology apart from so many other efficiency solutions are the dramatic savings that it brings to the clinical laboratory. Further standardization will assure the success of this revolutionary new technology. One of the main difficulties laboratory managers and personnel must deal with when studying solutions to reengineer a laboratory is familiarizing themselves with the multidisciplinary and technical terminology of this new and exciting field. The present review/glossary aims at giving an overview of the most frequently used terms within the scope of laboratory automation and to put laboratory automation on a sounder linguistic basis.

Serum markers of deranged myocardial collagen turnover: their relation to malignant ventricular arrhythmias in cardioverter-defibrillator recipients with heart failure.

BACKGROUND: Pathologic collagen remodeling has been involved in the occurrence of ventricular arrhythmias and sudden cardiac death in heart failure. The aim of the study was to investigate the relationship between malignant ventricular arrhythmias and cardiac collagen turnover indexes, expressing specific types of derangement in collagen physiology, in stable patients with an implantable cardioverter-defibrillator (ICD). METHODS: Seventy-four patients with an ICD and heart failure were studied. They had coronary artery disease (n = 42) or dilated cardiomyopathy, New York Heart Association classes I and II, and left ventricular ejection fraction 29% ± 1%. An ICD had been implanted for secondary (n = 36) or primary prevention of sudden cardiac death. We assessed (1) markers of collagen types I and III synthesis and their ratio: procollagen type I carboxyterminal peptide (PICP), procollagen type III aminoterminal peptide (PIIINP), and PICP/PIIINP; (2) markers of collagen degradation, degradation inhibition, and their ratio: matrix metalloproteinase 9 (MMP-9), tissue inhibitor of matrix metalloproteinase (TIMP) 1 (TIMP-1), and MMP-9/TIMP-1. Patients were prospectively followed up for 1 year. The number of episodes necessitating appropriate interventions for ventricular tachyarrhythmias (>170 beat/min) was related to the assessed parameters. RESULTS: Multivariate analysis revealed a significant relation between the number of tachyarrhythmic episodes and MMP-9/TIMP-1 (P = .007), PICP/PIIINP (P = .007), and ejection fraction (P = .04). No other significant relation was observed between arrhythmias and the remaining parameters. CONCLUSION: In heart failure, biochemical markers indicative of a deranged equilirium in myocardial collagen deposition/degradation and collagen I/III synthesis are related to ventricular arrhythmogenesis. Further studies are needed to investigate their predictive ability.

Angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism and circulating ACE levels are not associated with outcome in critically ill septic patients.

BACKGROUND: In critically ill patients independent studies have shown contradictory findings regarding the prognostic significance of the D/D genotype of the I/D angiotensin converting enzyme (ACE) polymorphism. The study aim was to evaluate the effect of both ACE I/D polymorphism and ACE serum levels on the clinical outcomes of critically ill septic patients. METHODS: This study recruited 186 Caucasian patients with sepsis, severe sepsis or septic shock. Epidemiological, clinical data, co-morbidities and severity scores were recorded. Measurements of serum ACE activity and genotyping for ACE I/D polymorphism were carried out. Primary outcomes were the 28- and the 90-day mortality; secondary outcomes included the number of days without renal or cardiovascular failure and ventilation-free days over the 28-day period following study enrolment. RESULTS: Neither 28- nor 90-day mortality were associated with ACE I/D polymorphism (p=0.59 and 0.34, respectively) or circulating ACE levels (p=0.17 and 0.25, respectively). Similarly, ACE polymorphism and levels were not related to ventilation-free days (p=0.14 and 0.25, respectively), days without cardiovascular failure (p=0.14 and 0.81, respectively) and days without renal failure (p=0.64 and 0.27, respectively). CONCLUSIONS: Neither ACE I/D polymorphism nor serum ACE levels seem to be significant prognostic factors of clinical outcomes in septic, critically ill patients.

Predictive value of B-type natriuretic peptides in detecting latent left ventricular diastolic dysfunction in beta-thalassemia major.

BACKGROUND: Beta-thalassemia major is a unique disease characterized by early diastolic dysfunction, related exclusively to iron myocardial deposition. N-terminal-proBNP(amino-terminal) (NT-proBNP) and B-type natriuretic peptide (BNP) are sensitive biomarkers for the detection of asymptomatic left ventricular (LV) dysfunction, and they have important diagnostic and prognostic implications. Using beta-thalassemia as a model disease with isolated diastolic dysfunction, we sought to investigate the predictive value of NT-proBNP and BNP levels in comparison with the conventional and new Doppler echocardiography indexes in detecting this disorder. METHODS: Seventy beta-thalassemia major patients (mean age 27.2 +/- 12.5 years) with normal LV systolic function (mean LV ejection fraction = 59% +/- 6.8%), and 50 healthy age-matched adults (control group: mean age 25.5 +/- 10.1 years, mean LV ejection fraction = 60% +/- 4.5%) were included. All subjects were studied thoroughly by tissue Doppler echocardiography and blood samples were taken for plasma NT-proBNP and BNP measurements at the same time. To examine LV diastolic function, patients were divided in 3 groups according to the E mitral/E mitral annulus ratio (E/E'): group A, patients without diastolic dysfunction: E/E' ratio <8; group B, patients with suspected diastolic dysfunction: E/E' ratio 8 to 15; group C, patients with documented diastolic dysfunction: E/E' ratio, >15. RESULTS: NT-proBNP and BNP levels were higher in thalassemic patients compared with the control group (NT-proBNP levels: 80 +/- 19 vs 21 +/- 4 pg/mL, P < .001; BNP levels: 34 +/- 6 vs 9 +/- 3 pg/mL, P < .001). NT-proBNP levels showed a statistically significant increase in group C in comparison to groups A and B, which was also detected between groups A and B (A vs B: P < .05). BNP levels were also significantly increased in group C in comparison to the other 2 groups, but there was no statistically significant difference between groups A and B. Using receiver operating characteristic analysis, NT-proBNP at a cut point of 49.2 pg/mL was highly accurate (area under curve: 0.97, P < .001) in ruling out diastolic dysfunction (E/E' <8) with a sensitivity of 93.7% and a specificity of 89.6%. CONCLUSIONS: BNP and NT-proBNP levels are significantly increased in documented left ventricular diastolic dysfunction, while NT-proBNP seems to have better predictive value in detecting latent left ventricular diastolic dysfunction in beta-thalassemia major.

Copeptin levels in patients with vasovagal syncope.

BACKGROUND AND PURPOSE: Vasovagal syncope (VVS) is linked to more than one pathophysiologic mechanisms. Copeptin, an emerging cardiovascular marker, is a surrogate for arginine-vasopressin, which increases following VVS. We aimed to assess the dynamic pattern of copeptin levels in typical VVS, categorized by the degree of vasoconstriction during orthostasis, and healthy controls. METHODS: The following groups were studied: Group A (n=21), with adequate limb vasoconstriction during the first min. of tilt, assessed by limb plethysmography (at least 30% flow reduction); Group B (n=15), showing impaired vasoconstriction during orthostasis (<10% reduction); Group C (n=18), history of VVS and negative tilt test result; Group D (n=18), healthy controls. Copeptin plasma levels were assessed before and 5min following tilt test positivity or termination. RESULTS: Baseline copeptin values were similar in all groups (8.3±6.4 in Group A, 5.7±2.3pmol/l in B, 6.0±1.9 in C, and 6.9±2.6 in D, p: 0.41). Significant increases in copeptin during tilt were observed in all Groups of VVS patients (A, B, C), including those with negative tilt (Group C: from 6.0±1.9 to 27.7±12.6pmol/l, p: 0.001), but not in controls. Following tilt termination, a greater increase was observed in copeptin values in Group B vs all other Groups A, C, and D (111.6±63.5 vs 29.5±51.3, 27.7±12.6, and 8.3±2.9, respectively). CONCLUSIONS: Copeptin increases following tilt not only in VVS with a positive response, but also in typical history patients with a negative test. Increased copeptin levels following orthostasis may be useful for diagnosing VVS.

The interplay between renin-angiotensin system activation, abnormal myocardial deformation and neurohumoral activation in hypertensive heart disease: a speckle tracking echocardiography study.

Angiotensin converting enzyme (ACE) promotes cardiac fibrosis. LV myocardial deformation and torsion are markers of subclinical myocardial dysfunction. We investigated the association of serum ACE levels with LV deformation markers in untreated hypertensives. In 120 untreated patients (age: 53.5 ± 11.2 years) with essential hypertension and 60 healthy controls, we measured (a) LV longitudinal, circumferential and radial strain (S), peak torsion and the percentage changes between peak twisting and untwisting at the end of early diastolic filling (%dpTw-UtwEDF) using speckle tracking echocardiography and (b) serum levels of ACE and NTproBNP. Compared to controls, patients had decreased longitudinal strain (-19.1 ± 2.9 vs. -21.7 ± 1.8%), increased peak twisting (19.1 ± 4.6 vs.14.0 ± 3.7 deg) but decreased %dpTw-UtwEDF (78 ± 8 vs. 86 ± 8%) and higher serum ACE levels (27.6 ± 8.0 vs 20.9 ± 7.1 U/ml) (p < 0.05 for all comparisons). Increasing serum ACE levels were related to impaired radial strain and longitudinal systolic SR (b = -0.41 and b = 0.31 respectively, p < 0.01), as well as to reduced %dpTw-UtwEDF (b = -0.37, p < 0.05). Furthermore, increasing serum ACE levels were related to increasing NTproBNP levels (b = 0.41, p < 0.01). In multivariate analysis, the above relations of serum ACE levels and LV function parameters remained significant after adjustment for other confounding factors (p < 0.01). The close link between serum ACE levels and impaired LV deformation suggests that activation of renin-angiotensin system is involved in the impairment of LV function resulting in elevated LV filling pressures causing the concomitant elevation of BNP levels in untreated hypertensive patients.

Shared genetic variants between serum levels of high-density lipoprotein cholesterol and wheezing in a cohort of children from Cyprus.

BACKGROUND: In a cohort of children in Cyprus, we recently reported low levels of high density lipoprotein cholesterol (HDL-C) to be associated with asthma. We examined whether genetic polymorphisms that were previously linked individually to asthma, obesity, or HDL-C are associated with both asthma and HDL-C levels in the Cyprus cohort. METHODS: We assessed genotypes frequencies in current-wheezers (n = 190) and non-asthmatic controls (n = 671) and HDL-C levels across several genotypes. Binary logistic regression models were used to assess the effect of genotypes on wheezing risk and examined whether this effect is carried out through changes of HDL-C. RESULTS: Of the 16 polymorphisms tested, two polymorphisms TNFa rs3093664 and PRKCA rs9892651 presented significant differences in genotype distribution among current-wheezers and controls. Higher HDL-C levels were noted in carriers of genotype GG of polymorphism TNFa rs3093664 that was protective for wheezing Vs AG and AA genotypes (65.3 Vs 51.8 and 53.3 mg/dl, p-value < 0.001 and p-value for trend = 0.028). In polymorphism PRKCA rs9892651, HDL-C levels were lower in carriers of CC and TC genotypes that were more frequent in current-wheezers Vs TT genotype (52.2 and 52.7 Vs 55.2 mg/dl, p-value = 0.042 and p-value for trend = 0.02). The association of TNFa rs3093664 with wheezing is partly mediated by its effect on HDL-C whereas association of PRKCA rs9892651 with wheezing appeared to be independent of HDL-C. CONCLUSIONS: We found evidence that two SNPs located in different genetic loci, are associated with both wheezing and HDL-C levels, although more studies in other populations are needed to confirm our results.

Association of arterial stiffness with coronary flow reserve in revascularized coronary artery disease patients.

AIM: To investigate the association of arterial wave reflection with coronary flow reserve (CFR) in coronary artery disease (CAD) patients after successful revascularization. METHODS: We assessed 70 patients with angiographically documented CAD who had undergone recent successful revascularization. We measured (1) reactive hyperemia index (RHI) using fingertip peripheral arterial tonometry (RH-PAT Endo-PAT); (2) carotid to femoral pulse wave velocity (PWVc-Complior); (3) augmentation index (AIx), the diastolic area (DAI%) and diastolic reflection area (DRA) of the central aortic pulse wave (Arteriograph); (4) CFR using Doppler echocardiography; and (5) blood levels of lipoprotein-phospholipase A2 (Lp-PLA2). RESULTS: After adjustment for age, sex, blood pressure parameter, lipidemic, diabetic and smoking status, we found that coronary flow reserve was independently related to AIx (b = -0.38, r = 0.009), DAI (b = 0.36, P = 0.014), DRA (b = 0.39, P = 0.005) and RT (b = -0.29, P = 0.026). Additionally, patients with CFR < 2.5 had higher PWVc (11.6 ± 2.3 vs 10.2 ± 1.4 m/s, P = 0.019), SBPc (139.1 ± 17.8 vs 125.2 ± 19.1 mmHg, P = 0.026), AIx (38.2% ± 14.8% vs 29.4% ± 15.1%, P = 0.011) and lower RHI (1.26 ± 0.28 vs 1.50 ± 0.46, P = 0.012), DAI (44.3% ± 7.9% vs 53.9% ± 6.7%, P = 0.008), DRA (42.2 ± 9.6 vs 51.6 ± 11.4, P = 0.012) and LpPLA2 (268.1 ± 91.9 vs 199.5 ± 78.4 ng/mL, P = 0.002) compared with those with CFR ≥ 2.5. Elevated LpPLA2 was related with reduced CFR (r = -0.33, P = 0.001), RHI (r = -0.37, P < 0.001) and DRA (r = -0.35, P = 0.001) as well as increased PWVc (r = 0.34, P = 0.012) and AIx (r = 0.34, P = 0.001). CONCLUSION: Abnormal arterial wave reflections are related with impaired coronary flow reserve despite successful revascularization in CAD patients. There is a common inflammatory link between impaired aortic wall properties, endothelial dysfunction and coronary flow impairment in CAD.