Carboxymethyl chitin (CM-chitin) was prepared at room temperature and characterized using 1H NMR, FTIR and elemental analysis methods. The prepared CM-chitin was then used as a hydrophilic matrix for the preparation of the aspirin sustained release tablets via the wet granulation technique. The aspirin release profiles of the prepared tablets in a simulated gastric fluid and simulated intestinal fluid, respectively, were studied with the rotating-basket dissolution method. The results showed that the aspirin release rate in simulated gastric fluid was lower than that in simulated intestinal fluid. Thus, CM-chitin proved to be a pH-sensitive hydrophilic matrix.

Water-soluble 2'-O-hydroxypropyltrimethylammoniumchitin chloride (2'-O-HTACCt) was prepared directly from p-chitin and 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) in basic medium. The effect of alkali concentration, reaction temperature, reaction time, and dosage of CTA on yield and degree of substitution (DS) of 2'-O-HTACCt were studied. These quaternized chitin derivatives were characterized by FTIR and H-1 NMR spectroscopy, conductometric titration, and elemental analysis methods. Research results indicate that beta-chitin can react directly with CTA to produce a water-soluble 2'-O-HTACCt derivative with a high DS. The optimal preparation conditions were determined to be 3540 wt % (aq NaOH), 40 degrees C (reaction temperature), 6 h (reaction time), and 4 (molar ratio of CTA to beta-chitin unit). (C) 2010 Elsevier Ltd. All rights reserved.

Carboxymethyl chitins (CM-chitins) with a high degree of substitution (DS), a low degree of deacetylation (DD), and high molecular weight were prepared directly from beta-chitin and characterized using (1)H NMR, FT-IR, TA, potentiometric titration, and elemental analysis methods. CM-chitins with different molecular weight were prepared using ultrasonic degradation method. Their abilities of moisture absorption and retention were investigated. The moisture-absorption ratio and moisture-retention ratio of CM-chitins increased as their DS increased. The moisture-absorption ratio and moisture-retention ratio of CM-chitins with high DS were close to that of hyaluronic acid (HA). The effect of molecular weight (>10(6)) of CM-chitin on its moisture-absorption ratio and moisture-retention ratio is neglectable.

Influence of temperature,total concentration and molar ratio on the aqueous two-phase system of sodium dodecylbenzene sulfonate(SDBS) and tetradecyltrimethylammnium chloride(TTAC) was investigated and the ternary phase diagram of the SDBS/TTAC/H2O system was determined.Extraction of L-tryptophan by this system was also studied.The results show that the aqueous two-phase system can be formed with n(SDBS)∶n(TTAC)=(1.6∶1)～(1∶4) at 20～40 ℃.The volume ratio of upper/lower phases decreases when TTAC molar ratio increases in the TTAC excessive region.The phase separation time decreases(in 12 min)and the volume ratio of upper/lower phases increases when n-butanol was added.The curve of conductance and the polarizing optical microscope photograph indicate that there is liquid crystal in the lower phase of the TTAC excessive region.This work has been confirmed to be innovative by the Southwest Information Center of Ministry of Science and Technology in《Certificate of New Technology Information Search》J 20071385 on August 16,2007.

Objectives - The primary aim of the study was to investigate whether there is a difference in plasma B-type natriuretic peptide (BNP) levels among the left ventricular systolic dysfunction caused by different types of heart disease.Methods and results - Plasma BNP was measured in patients with left ventricular systolic dysfunction as a result of mitral valve regurgitation (n=26), hypertension (n=36), coronary heart disease (n=37) and dilated cardiomyopathy (n=32). The left ventricular end-diastolic diameter and ejection fraction were assessed with echocardiography. The valvular heart disease group had more women and was younger (p < 0.05). There was no significant difference in the New York Heart Association functional class, left ventricular end-diastolic diameter and ejection fraction among the four groups (p < 0.05). The average plasma BNP was also similar among the four groups of patients. In each group, a significant correlation between the levels of BNP and the left ventricular end-diastolic diameter or ejection fraction was identified (p < 0.001).Conclusion - Plasma BNP concentrations during left ventricular systolic dysfunction are associated with left ventricular diameter and function, but they are not determined by the causes of the heart failure.

Aims: To investigate the level and clinical significance of plasma B-type natriuretic peptide (BNP) in patients with hyperthyroidism. Methods: Plasma BNP was measured in 32 healthy subjects and 67 patients with clinical hyperthyroidism. Left ventricular anatomy and function was assessed with echocardiography. Results: The average BNP in hyperthyroid patients was higher than that in healthy subjects (186±140 vs 34±17 ng/l, p =0.001). The increase in BNP was mainly found in hyperthyroid patients who had clinical and echocardiographic evidence of left ventricular dysfunction (250±190 ng/l). The BNP level in patients with hyperthyroidism, but with normal left ventricular function, was similar to that of the controls (37±17 vs 34±17, ng/l, p > 0.05). Multi-regression analysis showed that left atrial diameter and left ventricular ejection fraction were independently associated with the plasma levels of BNP. Conclusions: there is a significant elevation in plasma BNP in patients with hyperthyroidism; the increase is largely due to hyperthyroidism-induced left ventricular dysfunction. Measurements of plasma BNP may help to detect heart failure in patients with clinical hyperthyroidism.

The study was designed to investigate the impact of radiofrequency catheter ablation on the plasma level of B-type natriuretic peptide (BNP). In 36 patients who underwent catheter ablation of paroxysmal supraventricular tachycardia, the plasma level of BNP was analyzed before and after the ablation procedures. The plasma BNP at baseline, 30 minutes after the ablation, 3 and 24 hours after the ablation was 12.78 +/- 2.47, 18.45 +/- 4.02 (P = 0.446), 43.54 +/- 8.12 (P = 0.0001), and 17.88 +/- 4.71 (P = 0.493) pg/mL, respectively. Plasma troponin I was also increased 3 and 24 hours after the ablation (n = 10, P < 0.05). Multivariate regression analysis showed a significant correlation between the levels of BNP 3 hours after ablation and the preablation BNP and the total radiofrequency energy used for the ablation. We conclude that radiofrequency catheter ablation of supraventricular tachycardia increases the plasma level of BNP. The clinical significance of the ablation-induced increase in BNP needs to be further investigated.

Previous studies have found that plasma B-type natriuretic peptide (BNP) is elevated during left ventricular systolic or diastolic dysfunction. It is unclear whether the ventricular systolic and diastolic function is associated with different levels of plasma BNP. Plasma BNP was measured in 149 heart failure patients by a rapid point-of-care assay. The patients were divided into left ventricular diastolic dysfunction (n = 48), left ventricular systolic dysfunction (n = 62) and right ventricular systolic dysfunction group (n = 39). The mean BNP level in the left ventricular diastolic dysfunction, left ventricular systolic dysfunction and right ventricular systolic dysfunction was 115 +/- 80 pg/ml, 516 +/- 445 pg/ml and 345 +/- 184 pg/ml, respectively (p < 0.05). We concluded that ventricular systolic and diastolic dysfunction increases plasma BNP levels to a different extent. Left and right ventricular systolic dysfunction is associated with a higher level of plasma BNP than left ventricular diastolic dysfunction.

Aims: To investigate the value of B-type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction in patients with hypertension. Methods: The left ventricular diastolic function and plasma BNP levels were assessed prospectively in 135 hypertensive patients. Results: The plasma BNP in patients with (n=61) and without (n=74) diastolic dysfunction was 122 +/- 105 and 18 +/- 16 pg/ml, respectively (p<0.001). Increased BNP levels were associated with systolic blood pressure (p<0.05), left ventricular mass index (p<0.001), the E/A ratio of transmitral flow (p<0.01) and the isovolumic relaxation time (p<0.01). A receiver-operator characteristic curve showing the sensitivity and specificity of BNP against the echocardiography diagnosis of diastolic dysfunction revealed an area under the curve (accuracy) of 0.904 (p<0.01). Using a cut-off value of >40 pg/ml, the sensitivity and specificity of plasma BNP in diagnosing left ventricular diastolic dysfunction were 79% and 92%, respectively. Conclusions: The plasma BNP levels in patients with hypertension are closely related to left ventricular hypertrophy and filling impairment. Plasma BNP may be used to facilitate the diagnosis of left ventricular diastolic dysfunction. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

OBJECTIVE To investigate the factors that may predict the occurrence of depression in patients with primary hypertension. METHODS We conducted a cross-sectional survey on 891 hypertensive patients and 651 normal subjects (control group) from a single community. Zung self-rating depression scale (SDS) was applied to evaluate the symptoms of depression, which was diagnosed when the SDS score was >41. RESULTS There was no significant difference in gender distribution (female, 48.5 vs. 47.6%) and age (65.3±9.2 vs. 64.0±7.9 years) between the hypertensive control groups (P>0.05). Depression was diagnosed in 139 hypertensive patients (15.6%) and 27 (4.2%) control subjects (P<0.01). The average SDS score was higher in patients with hypertension duration of more than 3 years (33.3±9.0 vs. 30.6±7.6, P<0.001), in patients with severe hypertension (44.0±7.8 vs. 28.9±4.9, P<0.001) and in patients with a history of hospitalization for cardiovascular disorders (38.1±9.3 vs. 32.0±8.4, P<0.001). Multivariate regression analysis showed that the degree and the duration of hypertension, as well as hospitalization history, were independent predictors of depression in the hypertensive patients. CONCLUSIONS Hypertension is associated with a higher prevalence of depression that can be predicted by the duration and severity of hypertension as well as a history of hospitalization.

Objectives -To evaluate the impact of mild to moderate commissural calcification on the immediate outcomes of percutaneous balloon mitral valvuloplasty (PBMV).Methods and results -We analysed the results of 223 consecutive patients (mean age 37.6 +/- 8.7 years) who underwent PBMV for rheumatic mitral stenosis. Commissural calcification was identified with a two-dimensional echocardiography (echo) in 65 (29.1%) patients with the severity of calcification being graded from 0-3.The anatomy and function of the mitral valve were assessed by Wilkins echo score. In patients with no commissural calcification the increase in mitral valve area after PBMV was 0.90 +/- 0.42 cm(2), which was greater than the increase in those with calcification grade 1 (0.83 +/- 0.42 cm2, p<0.05),grade 2 (0.72 +/- 0.38 cm(2), p<0.05) and grade 3 (0.63 +/- 0.13 cm(2), p<0.05). In patients with an echo score of less than or equal to8, the presence of commissural calcification was associated with a smaller increase in mitral valve area (p <0.05) and a smaller reduction in New York Heart Association (NYHA) function class after PBMV (p<0.05). In patients with an echo score of more than 8, commissural calcification had no significant effect on the valve area increase and NYHA function class reduction (p>0.05).Conclusions - Commissural calcification has an adverse effect on the clinical results of PBMV. Detailed pre-procedural assessment of commissural calcification with echocardiography must be performed to provide background information on the immediate outcomes of PBMV.