Heart Failure ; Humans ; Natriuretic Peptide, Brain ; Peptide Fragments

Peptide mass mapping is the matching of experimentally generated peptides masses with the predicted masses of digested proteins contained in a database. To identify proteins by matching their constituent fragment masses to the theoretical peptide masses generated from a protein database, the peptide mass fingerprinting technique is used for the protein identification. Thus, it is important to know the theoretical mass distribution of the database. However, few researches have reported the peptide mass distribution of a database. We analyzed the peptide mass distribution of non-redundant protein sequence database in the NCBI after digestion with 15 different types of enzymes. In order to characterize the peptide mass distribution with different digestion enzymes, a power law distribution (Zipfs law) was applied to the distribution. After constructing simulated digestion of a protein database, rank-frequency plot of peptide fragments was applied to generalize a Zipfs law curve for all enzymes. As a result, our data appear to fit Zipfs law with statistically significant parameter values.
Databases, Protein* ; Dermatoglyphics ; Digestion ; Jurisprudence ; Peptide Fragments ; Peptides

The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; Oligopeptides ; Papain ; Peptide Fragments ; Sincalide ; chemical synthesis

The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; *Oligopeptides ; Papain ; Peptide Fragments ; Sincalide/*chemical synthesis

BACKGROUND/AIMS: Chronic right ventricular pacing (RVP) can lead to increased risks of ventricular dyssynchrony (VD), heart failure, and mortality. This study examined the factors influencing VD in patients treated with a permanent pacemaker (PPM). METHODS: The study enrolled 139 patients (M:F=1:1.35, 66.8+/-1.0 years) who had permanent pacemaker implanted [AAI (R): 11, VVI (R): 39, VDD (R): 50, DDD: 39]. Their clinical characteristics, 12-lead electrocardiogram (ECG), echocardiography, and laboratory parameters were evaluated. The patients were divided into two groups according to the presence of VD. RESULTS: VD was seen in 71.9% of the patients with a PPM. No significant difference was observed in the clinical characteristics, except for the indications and current action mode of the PPM. VD was more frequently associated with patients with AV block and ventricular pacing. The QRS duration and QTc interval were significantly wider in patients with VD (159.9+/-3.2 vs. 129.4+/-6.3 ms, p<0.001; 487.7+/-4.0 vs. 470.9+/-8.0 ms, p<0.05, respectively). On echocardiography, tricuspid regurgitation was more common in patients with VD. The N-terminal B-type natriuretic peptide (NT-proBNP) level was higher in the dyssynchrony group (431.4+/-66.1 vs. 202.8+/-40.8, p<0.05). CONCLUSIONS: Patients with AV block and ventricular pacing developed VD more frequently. A higher serum NT-proBNP level and prolonged QRS duration, QTc, and tricuspid regurgitation might be associated with VD.
Atrioventricular Block ; Echocardiography ; Electrocardiography ; Heart Failure ; Humans ; Natriuretic Peptide, Brain ; Peptide Fragments ; Tricuspid Valve Insufficiency

Assays for B-type natriuretic peptide (BNP) or N-terminal pro-brain BNP (NTproBNP) BNP are useful diagnostic method for evaluation of patients with dyspnea. And, natriuretic peptide levels have important prognostic value in heart failure. Therefore, measurements of BNP or NT-proBNP, taken together with conventional clinical assessment, may assist in the decision of treatment process. The following brief review summarizes available information concerning clinical significance of BNP or NT-proBNP.
Biomarkers ; Dyspnea ; Heart ; Heart Failure ; Humans ; Natriuretic Peptide, Brain ; Peptide Fragments

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia with a population prevalence of about 1%. Natriuretic peptide level is elevated in patients with AF with diastolic dysfunction even with a normal left ventricular (LV) ejection fraction. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level and Doppler echocardiographic parameters for diastolic function have shown correlation with LV filling pressures. We aimed to evaluate the relationship between echocardiographic parameters and serum NT-proBNP in patients with AF with preserved LV ejection fraction. METHODS: We examined transthoracic echocardiography and NT-proBNP levels in the patients with AF and patients with sinus rhythm. Blood samples were taken for serum NT-proBNP measurements within 24 hours of echocardiographic examination. The group 1 was the patients with sinus rhythm (n = 30, mean age 68 +/- 13 years) and the group 2 was the patients with AF (n = 33, mean age 70 +/- 14 years). RESULTS: The group 2 patients had significantly higher mitral E, E' (lateral annulus), E/E' (septal annulus), left atrial (LA) volume index, LA size, pulmonary vein diastolic velocity, and NT-proBNP level than those of group 1 patients (p < 0.05). The area under the receiver-operating characteristic curve showed a NT-proBNP had good diagnostic power for E/E' (septal annulus) > 15 in patients with AF at cutoff value of 433 pg/mL. CONCLUSION: NT-proBNP level is well correlated with Doppler echocardiographic parameters of diastolic function in patients with AF and preserved LV ejection fraction. NT-proBNP level more than 433 pg/mL may suggest elevated LV filling pressure in patients with AF.
Arrhythmias, Cardiac ; Atrial Fibrillation ; Echocardiography ; Echocardiography, Doppler ; Humans ; Natriuretic Peptide, Brain ; Peptide Fragments ; Prevalence ; Pulmonary Veins

BACKGROUND: BNP and NT-proBNP are very useful predictor of perioperative cardiac events. The authors therefore performed a retrospective study about the relationship between NT-proBNP and intraoperative hemodynamic stability. METHODS: The authors reviewed the chart of 126 patients which were consulted to cardiologists for preoperative cardiac evaluation from 2005 through 2007. All patients were divided into two groups; N-group (NT-proBNP < 300 pg/ml, n = 66) and H-group (NT-proBNP > or = 300 pg/ml, n = 60). The kinds of hemodynamic drugs and dosage and infusion time were calculated. Total amounts of hemodynamic drugs are scored by two methods. Infusion drugs were scored 30 points, bolus drugs (esmolol 30 mg, labetalol 10 mg, phenylephrine 50microg, ephedrine 10 mg, atropine 0.25 mg, nicardipine 0.5 mg) and preclusive nitroglycerin infusion were scored 5 points. Drug score is total sum of all scores. We compared the drug score of two groups. In addition, bivariate and partial correlation analysis were performed for the correlation of drug score. RESULTS: H-group showed a high (P = 0.029) drug score (17.68 +/- 21.78) more than N-group (10.13 +/- 15.79). H-group showed a low (P = 0.000) ejection fraction (51.69 +/- 12.90%) more than N-group (61.80 +/- 7.84%). But, only age (R: 0.234, P: 0.023) and ejection fraction (R: -0.222, P: 0.032) were correlated with drug score by partial correlation analysis. CONCLUSIONS: Patients with preoperative high NT-proBNP had decreased systolic function and demanded more hemodynamic drugs during noncardiac surgery. But, NT-proBNP was not correlated with drug score in itself.
Atropine ; Ephedrine ; Hemodynamics ; Humans ; Labetalol ; Natriuretic Peptide, Brain ; Nicardipine ; Nitroglycerin ; Peptide Fragments ; Phenylephrine ; Retrospective Studies

OBJECTIVETo investigate the correlation between pro-B-type natriuretic peptide (NT-proBNP) and heart rate variability (HRV) in patients with diabetes.

METHODSHRV and NT-proBNP levels were assessed in 58 patients with diabetes.The time domain and frequency domain indices and the level of NT-proBNP were compared between patients with normal and abnormal HRV, and the correlation of HRV index and NT-proBNP was analyzed.

RESULTSThe NT-proBNP level was significantly higher in patients with abnormal HRV than in those with normal HRV (320.2±88.3 vs 80.4±25.2 pg/ml, P<0.01).The level of NT-proBNP was negatively correlated with SDNN (r=-0.55, P<0.05), triangle index (r=-0.52, P<0.05), LF (r=-0.62, P<0.01), and VLF (r=-0.56, P<0.05).

CONCLUSIONNT-proBNP level is correlated with HRV, and an increased NT-proBNP indicates cardiac autonomic neuropathy in diabetic patients.

BACKGROUNDSeveral small sample-size observational studies evaluated the association of plasma brain natriuretic peptide (BNP) or N-terminal pro-brain natriuretic peptide (NT-proBNP) with atrial fibrillation (AF), but the results were contradictory. We aimed to perform a meta-analysis of relevant studies to evaluate the availability of this association.

METHODSWe performed an extensive literature search on PubMed, Web of Science (WOS) and the Cochrane Library databases. Pooled standardized mean difference (SMD) and 95% confidence interval (CI) were calculated to assess the strength of association using random effects models. We performed sensitivity and subgroup analyses to explore the potential sources of heterogeneity. We also estimated publication biases. Statistical analyses were performed using the STATA 12.0 software.

RESULTSA total of 11 studies including 777 cases and 870 controls were finally analyzed. Overall, the brain natriuretic peptide/N-terminal pro-brain natriuretic peptide levels were higher in atrial fibrillation patients than controls without atrial fibrillation.

RESULTSshowed that the SMD in the natriuretic peptide levels between cases and controls was 2.68 units (95% CI 1.76 to 3.60); test for overall effect z-score = 5.7 (P < 0.001). There was significant heterogeneity between individual studies (I(2) = 97.8%; P < 0.001). Further analysis revealed that differences in the assay of natriuretic peptide possibly account for this heterogeneity.

CONCLUSIONSIncreased BNP/NT-proBNP levels were associated with the presence of atrial fibrillation. This finding indicates that BNP/NT-proBNP may prove to be a biomarker of an underlying predisposition to AF.