The physiological feedback regulation mechanism of the heart rate variation due to the blood pressure variation is studied. The continuous closed-loop mathematical model of the heart rate feedback regulation system is constructed. Numerical simulation is completed based on the above model. The simulation results demonstrate that the regulation system has the ability to constrain the fluctuation of the blood pressure to certain extent. The results are helpful for the pathological studies of some hypertensive diseases.
Blood Pressure ; physiology ; Computer Simulation ; Feedback, Physiological ; Heart Rate ; physiology ; Humans ; Mathematics ; Models, Cardiovascular

Objective To investigate the clinical characteristics and risk factors of bacterial liver abscess (BLA) complicated with septicemia.Methods Fifty two BLA patients complicated with septicemia admitted in our hospital from January 2011 to December 2015 were retrospectively reviewed;and 52 cases of BLA without septicemia admitted at the same period were randomly selected as control group.The clinical manifestations, laboratory and radiographic findings, clinical outcome of these patients were analyzed.Logistic regression analysis was used to study the clinical features and risk factors of BLA complicated with septicemia.Results Compared to the control group, the BLA with septicemia group had higher prevalence rates in diabetes mellitus, malignant tumors, jaundice, albumin <35 g/L, BUN≥8.2 mmol/L, hyperglycemia, multiple abscesses and abscesses size ≥10 cm(P<0.05 or <0.01).The blood culture showed that K.pneumoniae(63.3%) was the most commonly isolated pathogen, followed by E.coli(16.7%).Univariate analysis revealed that diabetes mellitus(OR=2.200,95%CI 1.042-4.646), malignant tumors (OR=3.667,95%CI 1.023-13.143), albumin <35 g/ L(OR=2.800,95%CI 1.009-7.774), BUN≥8.2 mmol/L(OR=3.167,95%CI 1.265-7.929), hyperglycemia(OR=3.400,95%CI 1.254-9.216), multiple abscesses(OR=2.667,95%CI 1.043-6.815), abscesses size≥10 cm (OR=5.000,95%CI 1.096-22.820) were positively associated with bacterial liver abscess complicated with septicemia.Multivariate Logistic regression showed that abscesses size≥10 cm (OR=14.016,95%CI 1.354-145.070) was an independent risk factor for complication of with septicemia.Conclusion septicemia is a common complication for bacterial liver abscess, clinically effective measures shauld be taken to prevent and control risk factors associated with septicemia.

Numerical simulation of the thyroxin producing process of a human body is presented to analyze the dynamic and static variation laws of the process. The relationship between the static value of thyroxin and the reaction coefficients of various physiologic chemical reactions upon the producing thyroxin is clarified. The simulation results provided in this paper can be utilized as some reference data for clinical pathogeny analysis of some thyroxin diseases.
Computer Simulation ; Humans ; Mathematics ; Models, Theoretical ; Numerical Analysis, Computer-Assisted ; Thyroid Gland ; secretion ; Thyroxine ; biosynthesis

Objective:To explore the status quo of the readiness of evidence-based nursing practice for the maintenance and removal of children's central venous catheter (CVC) in 6 domestic medical institutions Pediatric Intensive Care Unit (PICU), analyze the obstacles faced by the application of CVC maintenance and removal evidence in PICU, so as to provide basis for formulating reform strategies.Methods:This study was a cross-sectional survey. In December 2019, 169 nurses from PICU of 6 medical institutions in Shanghai, Guangzhou, Shenzhen, Hangzhou, Xiamen and Hefei were selected by convenience sampling for investigation. The General Information Questionnaire and Clinic Readiness to Evidence-based Nursing Assessment (CREBNA) were used to evaluate the readiness of clinical nurses to evidence, organizational environment and promoting factors in the process of evidence-based practice. A total of 169 questionnaires were issued, and 169 valid questionnaires were recovered, with a valid recovery rate of 100%.Results:A total of 169 nurses were investigated in 6 evidence application sites. The total score of the multi center CREBNA was (136.96±15.33), which was 88.36% of the full score. The scores of the three dimensions were as follows: organizational environment (40.31±4.45), evidence dimension (53.43±6.14), and promoting factors (43.22±5.81). Four of the last five items in the score ranking were from the promoting factor, and the low score items in four places were all from the promoting factor.Conclusions:The best practice project of children's CVC maintenance in PICU is feasible. However, there are still some deficiencies in the preparation of various evidence application sites, especially in the promoting factors, which should be constantly improved to further promote and maintain the implementation of change.

Hip fractures are among the most common fractures in the elderly, presenting to be a leading cause of disability and mortality. Surgical treatment is currently the main treatment method for hip fractures. The incidence of perioperative malnutrition is increased after hip fractures in the elderly due to the comorbidities, decreased basal metabolic rate, accelerated protein breakdown, weakened anabolism and surgical stress. However, malnutrition not only increases the incidence of postoperative complications, but also leads to increased mortality, indicating an important role of perioperative nursing management of nutrition for the elderly patients with hip fractures. At present, there still lacks scientific guidance and application standards on perioperative nursing management of nutrition for the elderly patients with hip fractures. Therefore, the Orthopedic Nursing Committee of Chinese Nursing Association and the Editorial Board of Chinese Journal of Trauma organized relevant experts to formulate the Expert consensus on perioperative nursing management of nutrition for elderly patients with hip fractures ( version 2023) according to evidence-based medical evidences and their clinical experiences. Fourteen recommendations were made from aspects of nutrition screening, nutrition assessment, nutrition diagnosis, nutrition intervention and nutrition monitoring to provide guidance for perioperative nursing management of nutrition in elderly patients with hip fractures.

Objective To develop the automated preparation of 18F-Alfatide II using newly-designed 18F-minireactor and perform 18F-Alfatide D microPET/CT imaging in tumor.Methods The automated preparation of 18F-Alfatide H was developed by using 18F-microreactor and water phase Al18F-chelating method,and the radiochemical yield and quality analysis were measured.The nude mice bearing breast tumor ZR-75-1 and nasopharyngeal tumor CNE1 were established(n = 3 respectively).MicroPET/CT imaging was performed at 0.5,1.0 and 2.0 h after the injection of 18F-Alfatide II.The region of interest(ROI)was depicted and the tumor/muscle(T/M)ratio was calculated.Results 18F-Alfatide II was automatically prepared with the total synthesis time of 40 min,the radiochemical yield of(28±6)%(no decay corrected,n=11),and the radiochemical purity >97%.All quality analysis indexes accorded with the radiopharmaceutical requirements.18F-Alfatide II microPET/CT images of ZR-75-1 and CNE1 tumors were clear due to the high radioactivity uptake of tumor lesions(T/M ratio was greater than 4.0 at 1.0 h after injection).Conclusion Based on the 18F-minireactor,the,8F-Alfatide II can be prepared successfully with short synthesis time and high radiochemical yield,which can help the application studies in 18F-Alfatide II microPET/CT imaging.

Objective: To investigate the feasibility of early monitoring doxorubicin (DOX)-induced cardiotoxicity by apoptosis molecular imaging of 2-(5-[¹⁸F]fluoro-pentyl)-2-methyl-malonic acid (¹⁸F-ML-10) PET/CT. Methods: Forty-seven BALB/c mice were randomly divided into the chemotherapy group (n=30) and the control group (n=17) according to the random number table. The mice in chemotherapy group were intraperitoneally injected with DOX (4 mg/kg) once a week for 3 weeks and mice in the control group were injected with the same amount of normal saline. All mice were subjected to ¹⁸F-fluorodeoxyglucose (FDG) and ¹⁸F-ML-10 PET/CT imaging at day 0, 2, 9, 16, and left ventricular ejection fraction (LVEF) was continuously monitored using cine cardiac MR (cine-CMR) imaging. The region of interest (ROI) was delineated on PET/CT images, and the maximum percentage activity of injection dose per gram of tissue (%ID/g) was calculated. The mice were sacrificed after imaging, and the heart tissue was taken for HE staining and TdT-mediated dUTP nick end labeling (TUNEL) assay. One-way analysis of variance, independent-samples t test and Pearson correlation analysis were used to analyze the data. Results: In the chemotherapy group, the myocardial ¹⁸F-FDG uptake on day 0, 2, 9, 16 were (63.3±14.5), (93.7±24.0), (153.6±20.6) and (135.8±32.5) %ID/g respectively, and ¹⁸F-ML-10 uptake were (0.09±0.02), (0.18±0.03), (0.22±0.04) and (0.55±0.12) %ID/g respectively. Compared with baseline (day 0), ¹⁸F-FDG and ¹⁸F-ML-10 uptake were significantly increased in the chemotherapy group at each time point after DOX administration(F=6.823, 20.848, both P<0.01). The myocardial ¹⁸F-ML-10 and ¹⁸F-FDG uptake were essentially unchanged at all time points in the control group(F=2.036, 1.155, both P>0.05). TUNEL and HE staining indicated that the cardiomyocytes in the chemotherapy group showed obvious apoptosis and vacuolization, and the apoptotic index (AI) was positively correlated with the ¹⁸F-ML-10 uptake (r=0.950, P<0.01). The cine-CMR imaging results showed that the LVEF in the chemotherapy group continued to decrease after DOX administration (F=4.507, P<0.05), and significant difference was identified at day 16 (t=2.980, P<0.05). There was a significant negative correlation between ¹⁸F-ML-10 uptake and LVEF (r=-0.709, P=0.01). Conclusions Both ¹⁸F-FDG and ¹⁸F-ML-10 PET/CT imaging can early assess DOX-induced cardiotoxicity in vivo. Given the high targeting specificity of ¹⁸F-ML-10, it may have a greater clinical transformation advantage over ¹⁸F-FDG in early assessment of cardiotoxicity.