Knowledge, attitudes, and influencing factors of cancer patients toward approving advance directives in China.

PURPOSE: Many cancer patients do not have advance directives (ADs), which may lead to unwanted excessive or aggressive care when patients have lost decision-making capacity. The aim of this study was to investigate knowledge and attitudes of approving ADs and explore factors associated with willing to designate ADs among cancer patients in China. METHODS: We conducted semi-structured interview method investigating 753 in-patients with cancer in two cancer centers. RESULTS: Of those subjects, none of the cancer patients had an AD. Only 22.4 % (118 of 526) approved ADs. Comparing with the disapproved ADs group, the approved ADs group were more likely to discuss the AD with oncologist or nurse (χ (2) = 180.4, p < 0.001) in the cancer center (χ (2) = 244.1, p < 0.001), and they chose more comfort care (χ (2) = 18.8, p < 0.001). Most of cancer patients in the two groups wanted to die at home (72.8 %, 73.7 %, respectively). The older patients (OR, 1.04, 95 % CI, 1.02-1.07, p = 0.001), female (OR, 0.55, 95 % CI, 0.35-0.88, p = 0.013), with higher education levels (OR, 3.38, 95 % CI, 1.92-5.96, p < 0.001), with religious beliefs (OR, 2.91, 95 % CI, 1.71-4.94, p < 0.001), and with higher scores of ECOG (OR, 1.46, 95 % CI, 1.17-1.82, p = 0.001) were associated with desiring for ADs. CONCLUSIONS: Our findings indicate that there was a dearth of knowledge and different attitudes toward approving ADs among cancer patients, and some factors of demographic and clinical characteristics influenced their willing to designate ADs. This research highlights the importance of propagandizing the ADs to the public, especially to the patients, and further discussing with them when the time is ripe.

[Low Intensity Anticoagulation Therapy for Chinese Population with Heart Valve Replacement--3 000 Cases Follow-up].

OBJECTIVE: To investigate the effect of low-intensity anticoagulation therapy for Chinese population with heart valve replacement. METHODS: From January 2011 to March 2012, 3 000 patients with heart valve replacement in Fuwai Hospital and West China Hospital were followed-up for 1 year, the method and intensity of postoperative anticoagulation, as well as the complications were studied and analyzed. RESULTS: The rate of follow-up was 88.57%, and the cumulative follow-up was 1 726.1 patient-years (Pty). The mean oral warfarin dosage was (2.68 ± 6.45) mg/d, and the mean INR values of the patients treated in Fuwai Hospital and West China Hospital were 2.01 ± 1.10 and 186 ± 0.69 respectively (total 54 379 samples). The total rates of anticoagulation complication and mortality were 5.79% Pty and 0.12% Pty respectively, among which the morbidity and mortality of hemorrhage were 3.59% Pty and 0.12% Pty respectively, while the morbidity and mortality of thromboembolism were 2.03% Pty and 0.00% Pty respectively. There are no significant differences of actual anticoagulation intensity (P = 0.28)and the complication rates between the two hospitals . CONCLUSION: The optimal intensity scope (INR) of 1.5-2.5 (mean 1.8-2.0) is safe and efficient for Chinese patients with prosthetic heart valves, and no significant regional difference in the intensity of anticoagulation therapy required.

A novel "box lesion" minimally invasive totally thoracoscopic surgical ablation for atrial fibrillation.

INTRODUCTION: Minimally invasive surgical ablation is an emerging alternative method to catheter ablation and the full surgical maze procedure for nonpharmacologic treatment of atrial fibrillation (AF). We present a totally thoracoscopic "box lesion" radiofrequency ablation procedure in patients with paroxysmal or persistent AF. MATERIALS AND METHODS: From June 2011 to October 2012, 14 patients with lone paroxysmal (n = 7) or persistent AF (n = 7) were enrolled in this study. Procedures were performed through 3 5-12 mm holes on each side of the chest wall. A bipolar ablation device was used to create a box lesion in the posterior wall of the left atrium that encircled the 4 pulmonary veins (achieving bilateral pulmonary vein/posterior left atrial wall isolation). Perioperative complications were recorded for all patients. Freedom from AF was assessed by 24-hour Holter monitoring every 3 months or during symptoms of arrhythmia. RESULTS: The ablation was successfully performed in all patients, with median operation time of 128 minutes (range, 45 to 180 minutes). No operative mortality or morbidity were noted during the study period. Freedom from AF was achieved in 12 patients (85.7%) during follow-up (median follow-up 9 months). One patient with persistent AF was shifted to paroxysmal AF. No atrial flutter or atrial tachycardia was noted during the follow-up. CONCLUSION: These early results show that totally thoracoscopic surgical ablation using a unique "box lesion" procedure for persistent or paroxysmal AF is a feasible and effective method with good short-term results. Further study is necessary to validate this result.

Time-dependent changes of plasma inflammatory biomarkers in type A aortic dissection patients without optimal medical management.

OBJECTIVES: To investigate the time-dependent changes in plasma levels of interleukin-6, C-reactive protein, and tumor necrosis factor-α in patients with type A aortic dissection (TAAD) who received unoptimal medical management since the onset of dissections. DESIGN AND METHODS: Plasma levels of interleukin-6, C-reactive protein, and tumor necrosis factor-α were detected by ELISA and immuno-turbidimetric assay in 92 TAAD patients at hospital admission. Blood samples from 78 patients with uncontrolled hypertension and 82 healthy volunteers were also analyzed as controls. The occurrence of TAAD-related complication and its relationship with the plasma levels of these inflammatory biomarkers was also investigated. RESULTS: The concentrations of inflammatory mediators were significant higher in TAAD than those in the uncontrolled hypertension and the healthy group. The time to peak plasma level of IL-6.and TNF-α was shorter than that of CRP in TAAD group. In the TAAD group, 51 patients suffered TAAD-related complications, and their plasma level of CRP was significantly higher than that in patients without TAAD-related complications (94.5 ± 58.8 mg/L versus 47.4 ± 47.8 mg/L, p < 0.001). Also, CRP levels strongly correlated with the value of PaO2/FiO2 ratio (r = -0.69, p < 0.001) and creatinine (r = 0.60, p < 0.001). The time to the peak level of CRP was shorter and the duration of persistently high CRP level was longer in the complication group than those in the complication-free group. CONCLUSIONS: Elevated and persistently high levels of plasma CRP, IL-6 and TNF-α were associated with progressively development of the TAAD. The changing pattern of CRP might be a marker for diagnosis and prophylactic treatment of complications. Our findings suggested a critical role of the inflammation in the progression of dissection and TAAD-related complications.

Tricuspid valve obstruction and right heart failure due to a giant right atrial myxoma arising from the superior vena cava.

Myxomas are the most common primary cardiac tumors. The cardiac myxomas are mostly diagnosed within the atria, and only a few such tumors are reported to have arisen from atrioventricular valves or pulmonary vessels. The authors here present a case of 59-year-old Chinese woman who was hospitalized for exacerbating symptoms of tricuspid stenosis and right heart failure. Echocardiography revealed a giant right atrial myxoma arising from an extremely rare site, the anterior wall of the superior vena cava. With the aid of transesophageal echocardiography, the surgical resection was performed successfully with the patient achieving complete recovery.

Quality of life, physical diseases, and psychological impairment among survivors 3 years after Wenchuan earthquake: a population based survey.

BACKGROUND: Few research studies have addressed the long-term effects caused by catastrophes, and no study has ever explored the life quality, physical diseases, and psychological impairment of earthquake survivors at the same time. This study seeks to reveal survivors' quality of life, physical diseases, and mental health. METHODS: A cross-sectional survey was conducted through multi-stage sampling approach three years after the Wenchuan earthquake. RESULTS: A total of 2525 subjects were interviewed. Symptoms of PTSD were reported by 8.8% of the respondents from the seriously affected areas and 0.5%, the less hit areas. Prevalence of chronic diseases was 39.2% and 22.1% respectively, and two-week prevalence rate, 24.9% and 12.7% respectively. In the multivariate analysis, two-week prevalence, displacement, no regular income, receiving mental health support after the disaster, family members died or missing, injured due to the quake, and person who witnessed someone being killed or injured were independently associated with higher prevalence for symptoms of PTSD. Most subscales of SF-12 negatively correlated with age, chronic diseases, two-week prevalence, injured due to the disaster, home or property loss, and score of the 3-year PTSD symptoms, but positively correlated with higher education and higher household income. CONCLUSIONS: The rates of physical diseases and symptoms of PTSD were relatively high, and the quality of life was poor among victims in the hard-hit areas 3 years after the earthquake. Physical impairment correlated with symptom of PTSD, and both were negatively associated with quality of life.

[Effects of myocardial platelet rich plasma injection on rats with acute myocardial infarction:(99)Tc(m)-MIBI gated SPECT imaging evaluation results].

OBJECTIVE: To observe the effect of direct myocardial injection of platelet rich plasma (PRP) on cardiac function, ventricular remodeling and myocardial perfusion. METHODS: Myocardial infarction was induced in 30 Fisher rats by left anterior descending coronary artery (LAD) ligation. One week after LAD ligation, rats in control group (n = 15) received 0.5 ml saline myocardial injection and rats in PRP group (n = 11) received 0.5 ml PRP myocardial injection.(99)Tc(m)-methoxyisobutylisonitrile (MIBI) gated single photon-emission computed tomography (SPECT) imaging was applied at 1 week post LAD ligation and prior myocardial saline/PRP injection and repeated at 4 week post LAD ligation to assess myocardial perfusion and ejection fraction (EF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and the number of infarct segments. RESULTS: EF remained unchanged between 1 and 4 weeks post LAD ligation in control group and was significantly higher at 4 weeks post LAD ligation than at 1 week post LAD ligation in PRP group (P < 0.05). LVESV was significantly increased in the control group (P < 0.05) while remained unchanged in the PAP group (P < 0.05) at 4 weeks post LAD ligation compared that at 1 week post LAD ligation. LVEDV remained unchanged in the control group (P > 0.05) and significantly increased in the PRP group (P < 0.05) from 1 week to 4 weeks post LAD ligation. Myocardial perfusion remained unchanged in the control group and significantly improved in the PRP group at 4 week post LAD ligations. Histological examination also confirmed that PRP treatment can decrease infarct size [from (47 ± 19)% to (36 ± 11)%], increase ventricular wall thickness [from (3.1 ± 0.9) mm to(4.6 ± 1.8) mm] (P < 0.05). CONCLUSION: Myocardial PRP injection could improve cardiac function and reperfusion in this rat model of acute myocardial infarction.

Cardiocerebral resuscitation vs cardiopulmonary resuscitation for cardiac arrest: a systematic review.

OBJECTIVE: The objective of this study is to evaluate the efficacy of cardiocerebral resuscitation (CCR) vs cardiopulmonary resuscitation (CPR) for patients with out-of-hospital cardiac arrest (OHCA). METHODS: We conducted a systematic review of controlled trials and observational studies. We searched Cochrane Central Register of Controlled Trials; MEDLINE; Embase; and Chinese databases such as VIP, CNKI, WANFANG, and CBM from their inception to September 2010. Data from original studies were extracted and assessed with predefined criteria. RESULTS: Thirteen studies comprising 3 randomized controlled trials and 10 observational studies were included. Pooled analysis of 4 observational studies suggested that neurologically intact survival of patients with OHCA was improved in CCR group (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.07-1.97). Survival to hospital discharge in the CCR group was superior or at least equal to that in CPR group (randomized controlled trial OR, 1.25; 95% CI, 1.01-1.55; cohort studies OR, 1.15; 95% CI, 0.72-1.82; case-control studies OR 0.85; 95% CI, 0.65-1.12). In the subgroup analysis of patients with a shockable rhythm as an initial rhythm, survival to hospital discharge was significantly improved in the CCR group (cohort studies OR, 2.03; 95% CI, 1.44-2.86). However, when only noncardiac origin cardiac arrest was taken into consideration, survival rate was better in the CPR group (cohort studies OR, 0.87; 95% CI, 0.77-0.98). CONCLUSION: Cardiocerebral resuscitation might be equivalent or superior to CPR in patients with OHCA in both survival rate and neurologic benefits. Further work is needed to assess the efficacy of CCR for victims who had OHCA of noncardiac causes.

Protective effects of adenosine in rabbit sinoatrial node ischemia-reperfusion model in vivo: control of arrhythmia by hyperpolarization-activated cyclic nucleotide-gated (HCN)4 channels.

Disturbance of cardiac rhythm is one of the consequences of myocardial ischemia/reperfusion injury. Many researchers have prompted considerable interests in developing therapeutic approaches for its control. In present study, we want to determine whether that adenosine pre- and postconditioning have protective effects on sinoatrial node ischemia/reperfusion injury on morphology, arrhythmia score, serological markers (CK-MB and cTnT), SOD activities, MDA levels and expression of HCN4 channels in SA node cells. According to the arrhythmia score recorded, whether adenosine used in terms of ischemia or reperfusion, the total number of arrhythmia was significantly reduced, as well as the number of its episodes was also markedly decreased. We have also shown a clear correlation between HCN4 channels expression and the dysfunction of SA node cells. HCN4 immunoreactivity decreased after adenosine pre- and postconditioning, but changes were significantly smaller in the cells of the SA node compared with cells of I/R group. The content of cTnT, CK-MB and MDA in adenosine pre- and postconditioning group reduced significantly; but the level of SOD increased significantly. Histological examination and electron microscopy observations found in adenosine pre- and postconditioning group sinoatrial node injury also mitigated. These findings suggested that adenosine pre- or postconditioning were to reduce the incidence of ischemia/reperfusion arrhythmias, reduce myocardial ischemia reperfusion injury. The mechanism was to stabilize the SA node cells membrane and one possible mechanism involves modulation of HCN4 channels in pacemaker cells of the sinoatrial node.

Chest injuries associated with earthquakes: an analysis of injuries sustained during the 2008 Wen-Chuan earthquake in China.

PURPOSE: The goal of this study was to analyze the patterns, therapeutic modalities, and short-term outcomes of patients with chest injuries in the aftermath of the Wen-Chuan earthquake, which occurred on May 12, 2008 and registered 8.0 on the Richter scale. METHODS: Of the 1522 patients who were referred to the West China Hospital of Sichuan University from May 12 to May 27, 169 patients (11.1%) had suffered major chest injuries. The type of injury, the presence of infection, Abbreviated Injury Score (AIS 2005), New Injury Severity Score (NISS), treatment, and short-term outcome were all documented for each case. RESULTS: Isolated chest injuries were diagnosed in 129 patients (76.3%), while multiple injuries with a major chest trauma were diagnosed in 40 patients (23.7%). The mean AIS and the median NISS of the hospitalized patients with chest injuries were 2.5 and 13, respectively. The mortality rate was 3.0% (5 patients). CONCLUSIONS: Most of the chest injuries were classified as minor to moderate trauma; however, coexistent multiple injuries and subsequent infection should be carefully considered in medical response strategies. Coordinated efforts among emergency medical support groups and prior training in earthquake preparedness and rescue in earthquake-prone areas are therefore necessary for efficient evacuation and treatment of catastrophic casualties.

Challenges for rear hospital care of Wenchuan earthquake casualties: experience from West China Hospital.

To review the challenges and countermeasures in the hospital care for Wenchuan earthquake casualties and draw lessons for the protective response in the future. Medical records and laboratory findings of the victims admitted in West China Hospital (WCH) were retrospectively analyzed. Related data were compared between beforemath and aftermath of the earthquake and between WCH and frontier county hospitals. One thousand and thirty-one earthquake survivors were hospitalized, 1 358 victims underwent surgery and 142 victims were transferred to intensive care unit. The incidence of infection, crush syndrome and multiple organ dysfunction syndrome (MODS) was 39.6%, 20.7% and 2.3% respectively. Wound classification showed that the incidence of extremity damage was 72%, while the incidence of chest trauma, abdominal trauma and brain trauma was less than 10% respectively. Isolating rates of environmental pathogens were increased in the aftermath of earthquake, and the spectrum of the pathogens and related antibiotic sensitivities were quite different from those in the beforemath of earthquake. The social economic and population conditions in the earthquake-stricken areas affected the composition of the victims and the geographic features restricted the efficiency of rescue. Trauma-induced MODS, crush syndrome and severe infections all constituted the dilemma for the hospital care, to resolve whether the multidiscipline team work was proved to be an optimizing choice. For a more effective disaster protective response in the future, the study on rescue plan and the ladder therapies for massive casualties should be potentiated.

Anticancer mechanism of peptide P18 in human leukemia K562 cells.

Studies on the anticancer mechanism of peptide P18 in human leukemia K562 cells revealed that P18 causes the death of most K562 cells by depolarizing plasma membrane potential and enhancing membrane permeability, rather than activating the classical apoptosis pathway. The mechanistic studies indicate that disrupting plasma membrane is an effective approach to kill cancer cells and help design more effective peptide analogues in future cancer therapies.

Fluorescence studies on a designed self-assembling peptide of RAD16-II as a potential carrier for hydrophobic drug.

The self-assembling peptide, RAD16-II (Ac-RARADADARARADADA-NH2), has been shown to have many great applications in nanotechnology and tissue engineering. But few studies have been carried out to study the application of self-assembling peptides as a drug carrier. We used hydrophobic drug pyrene as a model and liposome vesicles to mimic bilayer membranes to study the ability of RAD16-II in drug encapsulation and transfer to lipid vesicles. It was found that this designed self-assembling peptide was able to stabilize hydrophobic drug in aqueous solution and deliver it into lipophilic environment. Analysis of the fluorescence excitation spectra showed that pyrene was present in the crystalline form when stabilized by RAD16-II and was able to be dispersed in egg phosphatidylcholine vesicles. This suggested that pyrene was completely released from RAD-Py mixture into the bilayer membranes. Furthermore, the concentration of pyrene transferred into the vesicles was quantified and its transfer rate was determined. The scanning electron micrograph image showed that pyrene microcrystals and peptide were absorbed by each other and the size of the pyrene-peptide complexes was larger than 10 microm. These data further demonstrated that this type of ionic complementary oligopeptides was able to significantly encapsulate hydrophobic drug and provide a new type of nanomaterials for delivering drugs.

Designed amphiphilic peptide forms stable nanoweb, slowly releases encapsulated hydrophobic drug, and accelerates animal hemostasis.

How do you design a peptide building block to make 2-dimentional nanowebs and 3-dimensional fibrous mats? This question has not been addressed with peptide self-assembling nanomaterials. This article describes a designed 9-residue peptide, N-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-C, which creates a strong fishnet-like nanostructure depending on the peptide concentrations and mechanical disruptions. This peptide is intramolecularly amphiphilic because of a single pair of ionic residues, Lys and Glu, at one end and nonionic residues, Phe, Cys, and Phe, at the other end. Circular dichroism and Fourier transform infrared spectroscopy analysis demonstrated that this peptide adopts stable beta-turn and beta-sheet structures and self-assembles into hierarchically arranged supramolecular aggregates in a concentration-dependent fashion, demonstrated by atomic force microscopy and electron microscopy. At high concentrations, the peptide dominantly self-assembled into globular aggregates that were extensively connected with each other to form "beads-on-a-thread" type nanofibers. These long nanofibers were extensively branched and overlapped to form a self-healing peptide hydrogel consisting of >99% water. This peptide can encapsulate the hydrophobic model drug pyrene and slowly release pyrene from coated microcrystals to liposomes. It can effectively stop animal bleeding within 30 s. We proposed a plausible model to interpret the intramolecular amphiphilic self-assembly process and suggest its importance for the future development of new biomaterials for drug delivery and regenerative medicine.

Risk factors of earthquake inpatient death: a case control study.

INTRODUCTION: At 2:28 p.m. on 12 May, 2008, a devastating earthquake measuring 8.0 on the Richter scale hit Wenchuan County, Sichuan Province in southwest China, and resulted in the deaths of thousands of people. To date, few epidemiological studies have been conducted on the determinants of the mortality of patients hospitalised after an earthquake. This paper is aimed at identifying the contributing factors of mortality and providing a clinical reference for the management of those injured in earthquakes. METHODS: A hospital-based case-control study was conducted. Cases included all deaths (n = 36) due to earthquake injuries in the West China Hospital. Controls were the quake survivors from the same hospital by at a ratio of four survivors to one death matched for sex and age. Data sources included death certificates and medical records. A conditional logistic regression was performed to assess the odds ratio (OR) of variables used in the study. A chi-squared test for trend was performed to reveal the possible relations between risk factor (variable) number and case fatality. RESULTS: People with a severe traumatic brain injury (TBI) had the greatest risk of death (adjusted OR = 253.3, 95% confidence interval (CI) = 8.9 to 7208.6), followed by patients with multiple system organ failure (MSOF; adjusted OR = 87.8, 95% CI = 3.9 to 1928.3). Prior major disease and infection significantly increased the risk of earthquake-related death (adjusted OR = 14.9, 95% CI = 1.9 to 119.0; adjusted OR = 13.7, 95% CI = 1.8 to 103.7; respectively). The number of fatal cases increased as the risk factor numbers also increased. CONCLUSIONS: Severe TBI, infection, MSOF and prior major disease are the significant determinants of earthquake-related inpatient death in the 2008 Wenchuan earthquake. Future research with a large sample size including macro- and micro-level factors is needed.

De novo design of a bolaamphiphilic peptide with only natural amino acids.

A new self-assembling bolaamphiphilic peptide has been designed and synthesized using only natural amino acids. This simple peptide is composed of two lysines connected by 4-8 alanines to maintain the characteristics of the traditional bolaamphiphiles. Based on an irregular secondary structure, it can self-assemble into nanospheres, nanorods, or nanofibers with lengths up to micrometers. The long nanofibers can be broken into smaller fragments by sonication, however, they could reassemble into nanofibers after incubation. Furthermore, the nanostructures were shown to have considerable thermostability. This new bolaamphiphilic peptide differs from any other self-assembling peptides or bolaamphiphiles, and possibly provides a new approach to fabricate nanomaterials.

Increased N-terminal pro-brain natriuretic peptide level predicts atrial fibrillation after surgery for esophageal carcinoma.

AIM: To evaluate the value of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level for predicting postoperative atrial fibrillation (AF) in patients undergoing surgery for esophageal carcinoma. METHODS: NT-proBNP levels were measured in 142 patients 24 h before and 1 h after surgery for esophageal carcinoma. All patients having a preoperative cardiac diagnosis by electrocardiogram (ECG), remained under continuous monitoring for at least 48 h after surgery, and then underwent clinical cardiac evaluation until discharge. RESULTS: Postoperative AF occurred in 11 patients (7.7%). AF patients were significantly older (69.6 +/- 12.2 years vs 63.4 +/- 13.3 years, P = 0.031) than non-AF patients. There were no significant differences in history of diabetes mellitus, sex distribution, surgical approach, anastomosis site, intraoperative hypotension and postoperative fever. The preoperative plasma NT-proBNP level was significantly higher in patients who developed postoperative AF (121.3 +/- 18.3 pg/mL vs 396.1 +/- 42.6 pg/mL, P = 0.016). After adjustment for age, gender, chronic obstructive pulmonary disease (COPD), history of cardiac diseases, hypertension, postoperative hypoxia and thoracic-gastric dilation, NT-proBNP levels were found to be associated with the highest risk factor for postoperative AF (odds ratio = 4.711, 95% CI = 1.212 to 7.644, P = 0.008). CONCLUSION: An elevated perioperative plasma BNP level is a strong and independent predictor of postoperative AF in patients undergoing surgery for esophageal carcinoma. This finding has important implications for identifying patients at higher risk of postoperative AF who should be considered for preventive antiarrhythmic therapy.

Temperature and pH effects on biophysical and morphological properties of self-assembling peptide RADA16-I.

It has been found that the self-assembling peptide RADA 16-I forms a beta-sheet structure and self-assembles into nanofibers and scaffolds in favor of cell growth, hemostasis and tissue-injury repair. But its biophysical and morphological properties, especially for its beta-sheet and self-assembling properties in heat- and pH-denatured conditions, remain largely unclear. In order to better understand and design nanobiomaterials, we studied the self-assembly behaviors of RADA16-I using CD and atomic force microscopy (AFM) measurements in various pH and heat-denatured conditions. Here, we report that the peptide, when exposed to pH 1.0 and 4.0, was still able to assume a typical beta-sheet structure and self-assemble into long nanofiber, although its beta-sheet content was dramatically decreased by 10% in a pH 1.0 solution. However, the peptide, when exposed to pH 13.0, drastically lost its beta-sheet structure and assembled into different small-sized globular aggregates. Similarly, the peptide, when heat-denatured from 25 to 70 degrees C, was still able to assume a typical beta-sheet structure with 46% content, but self-assembled into small-sized globular aggregates at much higher temperature. Titration experiments showed that the peptide RADA16-I exists in three types of ionic species: acidic (fully protonated peptide), zwitterionic (electrically neutral peptide carrying partial positive and negative charges) and basic (fully deprotonated peptide) species, called 'super ions'. The unordered structure and beta-turn of these 'super ions' via hydrogen or ionic bonds, and heat Brownian motion under the above denatured conditions would directly affect the stability of the beta-sheet and nanofibers. These results help us in the design of future nanobiomaterials, such as biosensors, based on beta-sheets and environmental changes. These results also help understand the pathogenesis of the beta-sheet-mediated neuronal diseases such as Alzheimer's disease and the mechanism of hemostasis.

[The expression of GATA-4 and Nkx2.5 gene in the transformation of Rattus mesenchymal stem cells into cardiomyocytes].

OBJECTIVE: To investigate the expression of the transcriptive factors, GATA-4 and Nkx2.5 gene, in the course of induction of mesenchymal stem cells (MSCs) into cardiomyocytes, and analyze its molecular biological mechanism. METHODS: Rattus Mesenchymal Stem Cells were cultured in vitro and 3rd generation cells were induced in 10 micromol/L 5-azacytidine, troponin I was checked with immunohistochemistry and Western blot, GATA-4 and NkX2.5 gene were analyzed by RT-PCR in 1, 2, 3 and 4 weeks respectively. RESULTS: Growth of MSCs stopped after being induced, trending to form colonies, troponin I positive expressed since 2nd week, GATA-4 and Nkx2.5 began to express in 1st week, increasing gradually, peak in 3rd week. CONCLUSION: GATA-4 and Nkx2. 5 gene expression increased gradually in the course of stem cells differentiation, which may control the rule of cardiomyocyte transcription.

[Tricuspid valve replacement and anticoagulation therapy: a report of 70 cases].

OBJECTIVE: To evaluate the operative indication, the choice of valve prostheses, and the method of anticoagulation therapy of tricuspid valve replacement (TVR). METHODS: From May 1998 to January 2008, 70 patients underwent TVR. There were 59 cases of rheumatic heart diseases. The operations included mitral and tricuspid valve replacement for 37 cases, triple valve replacement for 18 cases, isolated TVR for 13 cases, and tricuspid and aortic valve replacement for 2 cases. All the patients received oral anticoagulant therapy (warfarin) 2 d after the operations. RESULTS: There were 3 in-hospital deaths (4.3%) and 1 late death (0.4%). The follow-up rate was 88.1%, and the cumulative follow-up was 243.5 patient-years (pty). The anticoagulation-related event rate was 2.9% pty, and the mean INR value of 643 out-patient samples was 1.87 +/- 0.68. Post-operative heart function NYHA classification: 52 cases in class I to II, and 7 cases in class III. CONCLUSIONS: TVR should be indicated for severely damaged and deformed tricuspid valve of rheumatic heart diseases. Bileaflet mechanical valve is a suitable prosthesis for TVR. The optimal anticoagulation therapy intensity of TVR needs to be investigated.