Rational design,preparation and characterization of recombinant Ag85B variants and their glycoconjugates with T-cell antigenic activity against Mycobacterium tuberculosis

Tuberculosis is the deadliest infectious disease in the world. The variable efficacy of the current treatments highlights the need for more effective agents against this disease. In the past few years, we focused on the investigation of antigenic glycoconjugates starting from recombinant Ag85B (rAg85B), a potent protein antigen from Mycobacterium tuberculosis. In this paper, structural modifications were rationally designed in order to obtain a rAg85B variant protein able to maintain its immunogenicity after glycosylation. Lysine residues involved in the main T-epitope sequences (namely, K30 and K282) have been substituted with arginine to prevent their glycosylation by a lysine-specific reactive linker. The effectiveness of the mutation strategy and the detailed structure of resulting neo-glycoconjugates have been studied by intact mass spectrometry, followed by peptide and glycopeptide mapping. The effect of K30R and K282R mutations on the T-cell activity of rAg85B has also been investigated with a preliminary immunological evaluation performed by enzyme-linked immunospotting on the different variant proteins and their glycosylation products. After glycosylation, the two variant proteins with an arginine in position 30 completely retain the original T-cell activity, thus representing adequate antigenic carriers for the development of efficient glycoconjugate vaccines against tuberculosis.

Recombinant Ag85B variants were designed and prepared to improve the immunogenicity of a potential glycoconjugate vaccine against tuberculosis.     

Introgression of a synthetic sex ratio distortion transgene into different genetic backgrounds of Anopheles coluzzii

The development of genetically modified mosquitoes (GMM) and their subsequent field release offers innovative approaches for vector control of malaria. A non-gene drive self-limiting male-bias Ag(PMB)1 strain has been developed in a 47-year-old laboratory G3 strain of Anopheles gambiae s.l. When Ag(PMB)1 males are crossed to wild-type females, expression of the endonuclease I-PpoI during spermatogenesis causes the meiotic cleavage of the X chromosome in sperm cells, leading to fertile offspring with a 95% male bias. However, World Health Organization states that the functionality of the transgene could differ when inserted in different genetic backgrounds of Anopheles coluzzii which is currently a predominant species in several West-African countries and thus a likely recipient for a potential release of self-limiting GMMs. In this study, we introgressed the transgene from the donor Ag(PMB)1 by six serial backcrosses into two recipient colonies of An. coluzzii that had been isolated in Mali and Burkina Faso. Scans of informative Single Nucleotide Polymorphism (SNP) markers and whole-genome sequencing analysis revealed a nearly complete introgression of chromosomes 3 and X, but a remarkable genomic divergence in a large region of chromosome 2 between the later backcrossed (BC6) transgenic offspring and the recipient paternal strains. These findings suggested to extend the backcrossing breeding strategy beyond BC6 generation and increasing the introgression efficiency of critical regions that have ecological and epidemiological implications through the targeted selection of specific markers. Disregarding differential introgression efficiency, we concluded that the phenotype of the sex ratio distorter is stable in the BC6 introgressed An. coluzzii strains.     

A comprehensive management system for heart failure improves clinical outcomes and reduces medical resource utilization]

BACKGROUND: Hospital admissions for heart failure are common and readmission rates are high. Many admissions and readmissions may be avoidable, so that alternative strategies are needed to improve long-term management. METHODS: We conducted a randomized trial of the effect of a guideline-based intervention on rates of readmission within 90 days of hospital discharge and costs of care for patients who were hospitalized due to decompensated heart failure. The intervention consisted of comprehensive education of the patient and family, a prescribed diet and intensive application of guidelines' recommendations on pharmacological therapy. The intervention started before discharge and continued thereafter with follow-up visits for up to 3 months. Two hundred and nine guideline-managed patients were compared to 209 concurrent normally-discharged patients. RESULTS: Patients in the study group were more prescribed beta-blockers, ACE-inhibitors, angiotensin receptor blockers, and spironolactone. Sixteen patients (8%) in the intervention group and 31 (15%) among controls were readmitted for DRG 127, within 3 months of discharge (Fisher's exact test, p < 0.01), while the 6-month mortality rate was similar between groups (9 and 11.5% respectively). Quality of life significantly improved from 5.6 +/- 1.0 to 6.1 +/- 1.9 (Mann-Whitney U-test, p < 0.05). The overall costs of care were lower for guideline-managed patients (110 vs 150 Euro per patient per month), due to the lower readmission rates. CONCLUSIONS: Our study showed that a guideline-based management program for patients with heart failure at discharge improves quality of life and reduces readmission for DRG 127 and total bed days, allowing relevant cost savings.     

The x-ray structure of D-amino acid oxidase at very high resolution identifies the chemical mechanism of flavin-dependent substrate dehydrogenation

Flavin is one of the most versatile redox cofactors in nature and is used by many enzymes to perform a multitude of chemical reactions. d-Amino acid oxidase (DAAO), a member of the flavoprotein oxidase family, is regarded as a key enzyme for the understanding of the mechanism underlying flavin catalysis. The very high-resolution structures of yeast DAAO complexed with d-alanine, d-trifluoroalanine, and l-lactate (1.20, 1.47, and 1.72 A) provide strong evidence for hydride transfer as the mechanism of dehydrogenation. This is inconsistent with the alternative carbanion mechanism originally favored for this type of enzymatic reaction. The step of hydride transfer can proceed without involvement of amino acid functional groups. These structures, together with results from site-directed mutagenesis, point to orbital orientation/steering as the major factor in catalysis. A diatomic species, proposed to be a peroxide, is found at the active center and on the Re-side of the flavin. These results are of general relevance for the mechanisms of flavoproteins and lead to the proposal of a common dehydrogenation mechanism for oxidases and dehydrogenases.     

Über die Pulsform und Wellengeschwindigkeit in den Fingerarterien

Ohne ZusammenfassungMit 8 Abbildungen.     

Heart rate as a predictor of development of sustained hypertension in subjects screened for stage 1 hypertension: the HARVEST Study

OBJECTIVE: Whether heart rate predicts the development of sustained hypertension in individuals with hypertension is not well known. We carried out a prospective study to investigate whether clinic and ambulatory heart rates assessed at baseline and changes in clinic heart rate during 6 months of follow-up were independent predictors of subsequent blood pressure (BP). METHODS: The study was conducted in a cohort of 1103 white, stage 1 hypertensive individuals from the HARVEST study, never treated for hypertension and followed-up for an average of 6.4 years. Data were adjusted for baseline BP, age, sex, body fatness, physical activity habits, parental hypertension, duration of hypertension, cigarette smoking, alcohol consumption, and change of body weight from baseline. RESULTS: Clinic heart rate and heart rate changes during the first 6 months of follow-up were independent predictors of subsequent systolic blood pressure (SBP) and diastolic blood pressure (DBP) regardless of initial BP and other confounders (all P < 0.01). A significant interaction was found between sex (male) and baseline resting heart rate on final SBP (P = 0.017) and DBP (P < 0.001). The ambulatory heart rate and the heart rate white-coat effect did not add prognostic information to that provided by the clinic heart rate. Patients whose heart rate was persistently elevated during the study had a doubled fully adjusted risk (95% confidence interval 1.4-2.9) of developing sustained hypertension in comparison with subjects with a normal heart rate. CONCLUSIONS: Baseline clinic heart rate and heart rate changes during the first few months of follow-up are independent predictors of the development of sustained hypertension in young persons screened for stage 1 hypertension.     

Rapid brain natriuretic peptide test and Doppler echocardiography for early diagnosis of mild heart failure

BACKGROUND: The early identification of patients at risk for the development of clinical heart failure (HF) is a new challenge in an effort to improve outcomes. METHODS: We prospectively evaluated whether the combination of brain natriuretic peptide (BNP) measurements (Triage BNP test, Biosite Diagnostics) and echocardiography would effectively stratify patients with new symptoms in a cost-effective HF program aimed at early diagnosis of mild HF. A total of 252 patients were referred by 100 general practitioners. RESULTS: Among the study population, the median BNP value was 78 ng/L (range, 5-1491 ng/L). BNP concentrations were lower among patients without heart disease [median 15 ng/L (range, 5-167 ng/L); n = 96] than among patients with confirmed HF [median, 165 ng/L (22-1491 ng/L); n = 157; Mann-Whitney U-test, 12.3; P <0.001]. Patients were grouped into diastolic dysfunction [BNP, 195 (223) ng/L], systolic dysfunction [BNP, 290 (394) ng/L], and both systolic and diastolic dysfunction [BNP, 776 (506) ng/L]. In this model, a cutoff value of 50 ng/L BNP increases the diagnostic accuracy in predicting mild HF, avoiding 41 echocardiograms per 100 patients studied, with a net saving of 14% of total costs. CONCLUSIONS: Blood BNP concentrations, in a cost effective targeted screening, can play an important role in diagnosing mild HF and stratifying patients into risk groups of cardiac dysfunction.     

Optimizing fluid management in patients with acute decompensated heart failure (ADHF): the emerging role of combined measurement of body hydration status and brain natriuretic peptide (BNP) levels

The study tests the hypothesis that in patients admitted with acutely decompensated heart failure (ADHF), achievement of adequate body hydration status with intensive medical therapy, modulated by combined bioelectrical vectorial impedance analysis (BIVA) and B-type natriuretic peptide (BNP) measurement, may contribute to optimize the timing of patient’s discharge and to improve clinical outcomes. Three hundred patients admitted for ADHF underwent serial BIVA and BNP measurement. Therapy was titrated to reach a BNP value of <250 pg/ml, whenever possible. Patients were categorized as early responders (rapid BNP fall below 250 pg/ml); late responders (slow BNP fall below 250 pg/ml, after aggressive therapy); and non-responders (BNP persistently >250 pg/ml). Worsening of renal function (WRF) was evaluated during hospitalization. Death and rehospitalization were monitored with a 6-month follow-up. BNP value on discharge of ≤250 pg/ml led to a 25% event rate within 6 months (Group A: 17.4%; Group B: 21%, Chi2; n.s.), whereas a value >250 pg/ml (Group C) was associated with a far higher percentage (37%). At discharge, body hydration was 73.8 ± 3.2% in the total population and 73.2 ± 2.1, 73.5 ± 2.8, 74.1 ± 3.6% in the three groups, respectively. WRF was observed in 22.3% of the total. WRF occurred in 22% in Group A, 32% in Group B, and 20% in Group C (P = n.s.). Our study confirms the hypothesis that combined BNP/BIVA sequential measurements help to achieve adequate fluid balance status in patients with ADHF and can be used to drive a “tailored therapy,” allowing clinicians to identify high-risk patients and possibly to reduce the incidence of complications secondary to fluid management strategies.     

B-type natriuretic peptide can predict the medium-term risk in patients with acute heart failure and preserved systolic function

BACKGROUND: Half of patients with heart failure (HF) have preserved left ventricular ejection fraction (LVEF). Neurohormonal activation characterizes the disease and measurement of plasma B-type natriuretic peptide (BNP) indicates the severity of left ventricular dysfunction. The purpose of this study was to test the hypothesis that measurement of BNP levels in ambulatory patients with HF and preserved LVEF can predict the occurrence of cardiovascular events in the next 6 months. METHODS AND RESULTS: We enrolled 233 consecutive patients admitted to the Outpatient Heart Failure Clinic (OHFC), on stabilization after an episode of acute HF, with a LVEF > 50%. Standard echocardiography was performed and left ventricular systolic/diastolic function was assessed. Plasma BNP levels were measured on admission to OHFC. Patients were followed for 6 months; the main endpoint combined cardiovascular death or readmission for HF. Among the 233 patients discharged, 48 endpoints occurred (death: n = 15; readmission: n = 33). Receiver operated curve analysis shows that BNP levels are strong predictors of subsequent events (area under the curve = 0.84; CI = 0.78-0.88). Multivariate Cox regression showed that the cutoff values identified by receiver operated curve analysis (200-500 pg/mL) of the neurohormone are the most accurate predictors of events: HR = 2.2 (P < .04) and HR = 5.8 (P < .001), respectively, for 201-499 pg/mL and > or = 500 pg/mL ranges. CONCLUSION: BNP level is a strong predictor for cardiovascular mortality and early readmission in patients with diastolic HF. The results suggest that BNP levels might be used successfully to guide the intensity of follow-up after a decompensation, because increased BNP levels were associated with a progressively bad prognosis.