OBJECTIVE: To explore the possibility of repair long segmental bone defects and preventing infection with cefazolin loaded bone matrix gelatin (C-BMG). METHODS: C-BMG was made from putting cefazolin into BMG by vacuum adsorption and freeze-drying techniques. The sustaining period of effective drug concentration in vitro and in vivo was detected by inhabition bacteria, and the drug concentration in local tissues (bone and muscle) and plasma after implantation of C-BMG was examined by high performance liquid chromatography(HPLC). RESULTS: The effective inhibition time to staphylococcus aureus of C-BMG was 22 days in vitro, while 14 days in vivo. The drug concentration in local tissues(bone and muscle) were higher than that of plasma, and the drug concentration in local tissues was higher in early stage, later it kept stable low drug release. It suggested that C-BMG had excellent ability to repair segmental long bone defects. CONCLUSION: C-BMG can gradually release cefazolin with effective drug concentration and has excellent ability to repair segmental long bone defects. It may be a novel method to repair segmental long bone defects and prevent infection after the operation.
Objective To evaluate the influence of tidal volume on the accuracy of stroke volume variation ( SVV) to predict volume state of pigs with ventilation.Methods Thirty-six healthy pigs were anesthetized after tracheal intubation and ventilated. With the envelope method, they were randomized into a normovolemia group, a hemaerrhagic shock group, and a hypervolemia group, with 12 pigs in each group. The pigs in the hemaerrhagic shock group were removed 20 percent of blood, and the pigs in the hypervolemia group received additional infusion of 20 percent 6% hydroxyethyl starch. In each group, ventilator settings were changed in a randomized order by changing VT [ VT = 5 mL/kg ( VT5 ) , VT =10 mL/kg ( VT10 ) , and VT =15 mL/kg ( VT15 ) ] . Hemodynamic measurements [ heart rate ( HR) , mean arterial boold pressure ( MAP) , systemic vascular resistance index ( SVRI) , cardiac index ( CI) , stroke volume index ( SVI) , intrathoracic blood volume index( ITBVI) , and SVV] were obtained after 10 minutes of stabilization. Results SVV was increased in the hemaerrhagic shock group comparing with the normovolemia group for VT10 [ ( 21 ±5) % vs. ( 11 ±2) % , P lt;0. 05] , but SVV was decreased in the hypervolemia group comparing with the normovolemia group [ ( 7 ±2) % vs. ( 11 ±2) % , P lt; 0. 05] . The variation tendency for VT15 was the same with VT10 , moreover SVV were all above 12% for the hemaerrhagic shock group, the normovolemia group, and the hypervolemia group [ ( 30 ±7) % , ( 19 ±3) % , and ( 15 ±4) % ] . There were no significant diffrences among the hemaerrhagic shock group, hypervolemia group and normovolemia group [ ( 8 ±6) % ,( 7 ±5) % , and ( 7 ±4) % , P gt; 0. 05] for VT5 . Conclusions SVV was a precise indicator of cardiac preload, but SVV was less sensitive to the changes of volume during low tidal volume ( 5 mL/kg) ventilation. The threshold of SVV for predicting fluid responsiveness maybe above 12% with a high tidal volume ( 15 mL/kg) ventilation.
To evaluate the efficacy and the surgical procedures of submandibular sialoadenectomy by a modified retroauricular approach. Methods Between October 2008 and April 2009, 8 patients with benign submandibular gland disorders underwent removal of benign submandibular gland lesions using a retroauricular approach. There were 4 males and 4 females with an average age of 38.5 years (range, 32-54 years), including 3 pleomorphic adenoma and 5 chronic sialadenitis with sialol ithiasis. The disease duration was from 2 months to 5 years. The anterior facial vein and the facial artery were reserved only by the l igation of branching vessels in the submandibular gland. Results Submandibular sialoadenectomy were successfully performed in 8 cases. The operative time was 45-75 minutes (mean, 60 minutes). All incisions obtained heal ing by first intention. No nerve paralysis occurred, including marginal mandibular branch of the facial nerve, the l ingual nerve, and hypoglossal nerve. One patient had poor blood circulation of flap due to excessive traction during operation, but it returned normal after 24 hours without special treatment. Other flaps had good blood circulation. All patients were followed up 1-6 months (mean, 3 months). The incision scars were hidden with satisfactory appearance. Conclusion The modified retroauricular approach has some advantages such as simple operation, better cosmetic outcome, and no compl ication.
Objective To assess the relationship between the change in fluid overload at 48 h after initiation of continuous renal replacement therapy (CRRT) and 28-day mortality in critically ill patients with acute kidney injury (AKI). Methods A retrospective cohort study was performed using data from the MIMIC-IV database from 2008 to 2019. Patients who received CRRT for AKI for more than 24 h within 14 d of admission to the intensive care unit were included. The exposure variable was the proportion of change of fluid overload (ΔFO%, defined as the difference between body weight normalized fluid input and output) at 48 h after CRRT initiation, and the endpoint was 28-day mortality. Generalized additive linear regression models and logistic regression models were used to determine the relationship between the exposure and endpoint. Results A total of 911 patients were included in the study, with a median (lower quartile, upper quartile) ΔFO% of −3.27% (−6.03%, 0.01%) and a 28-day mortality of 40.1%. Generalized additive linear regression model showed that the ΔFO% at 48 h after CRRT initiation was associated with a J-shaped curve with 28-day mortality. After adjusting for other variables, as compared with the second quartile of ΔFO% group, the first quartile group [odds ratio (OR)=1.23, 95% confidence interval (CI) (0.81, 1.87), P=0.338] was not associated with higher risk of 28-day mortality, while the third quartile group [OR=1.54, 95%CI (1.01, 2.35), P=0.046] and the fourth quartile group [OR=2.05, 95%CI (1.32, 3.18), P=0.001] were significantly associated with higher risk of 28-day mortality. There was no significant relationship between ΔFO% groups and 28-day mortality in the first 24-hour after CRRT initiation (P>0.05), but there was a linear relationship between ΔFO% and 28-day mortality in the second 24-hour after CRRT initiation, the larger the ΔFO%, the higher the mortality rate [OR=1.10, 95%CI (1.04 1.16), P<0.001 for per 1% increase]. ConclusionIn critically ill patients with AKI, the ΔFO% greater than −3.27% within 48 h after CRRT initiation is independently associated with an increased risk of 28-day mortality, and the goals of CRRT fluid management may be dynamical.
To introduce a rat model of the conversion of acute edematous pancreatitis (AEP) to necrotizing pancreatitis (ANP). One hundred and seven Sprague-Dawley rats were randomized in three experimental groups as follows: sham operation control group and AEP group and ANP group. AEP was induced by pancreatic duct ligation and exocrine stimulation, ANP was induced same as AEP，but with a large dose of dextran-110 (500mg/kg) intravenously. The serum concentration of amylase increased significantly in AEP group and ANP group. Cytosolic free Ca2+ concentration in isolated pancreatic acinar cells increased consistently after induction of ANP. Homorrhage, parenchymal necrosis and calcium deposits in acinar cells were observed in pancreas in ANP group. Ultrastructural examination showed desquamation and necrosis of the endothelium of the pancreatic capillary in ANP group. These results suggest that ischemia may induce the conversion of AEP to ANP via acinar cell Ca2+ overloading. The rat model would seem to be a suitable animal model for studying aggravating mechanism of acute pancreatitis.
OBJECTIVETo study the repairing method of facial nerve defect using nerve elongation, and the biomechanical properties of peripheral nerves. METHODS A novel device for peripheral nerve elongation was designed and manufactured. With the device, facial nerves of rabbits were expanded acutely and chronically by string-type loading. The facial nerves were studied with histological and electrophysiological examinations before and after elongation. RESULTS There were no considerable necrosis, degeneration, and infection in the facial nerves after elongation. The experimental animals took food normally and their body temperature were stable. Histological examinations showed dispersing Sunderland degree III injury and occasionally broken capillary blood vessels in the acute group, thicker nerve and fibroblasts hyperplasia between nerve bundles in the chronic group. The electromyogram(EMG) of buccal muscle and nerve conductive velocity(NCV) showed the maximal range was (18.7 +/- 2.4)% in the acute group, and (30.8 +/- 2.4)% in the chronic group. CONCLUSION It suggests that the novel nerve elongation method is feasible, and it can be used to study the nerve elongation basically and clinically.
ObjectiveTo compile the information overload severity scale in the situation of coronavirus disease 2019 epidemic, and evaluate the reliability and validity.MethodsFrom February to March 2020, according to the procedures of literature analysis, semi-structured interview, and expert consultation, an initial scale was formed; and then the online scale was measured, and the scale items were screened based on the measured results of the scale. The reliability was evaluated by Cronbach’s α coefficient, and the validity was tested by exploratory factor analysis.ResultsThere were 8 items in the initial scale. The scale items were screened based on the degree of dispersion, the correlation coefficient with the total score, and the factor-load-related indicators, and finally a 7-item scale was formed. The factor analysis results of the scale showed that one component could be extracted from the scale, and the reliability analysis showed that the total Cronbach’s α coefficient of the scale was 0.863.ConclusionThe information overload severity scale has good reliability and validity, which can provide strong support for related research after the outbreak of coronavirus disease 2019 and other major public events.
ObjectiveTo establish a mouse model of pressure overload-induced heart failure via suprasternal notch approach. MethodsMale mice were separated into a sham group and an experiment group. Through suprasternal notch approach, the aortic arch port between the origin of the right innominate and left common carotid arteries was partially clipped with tantalum clip, which had a remaining opening of 0.35 mm or 0.25 mm in diameter to cause progres-sively increased afterload. Echocardiography was performed 10 weeks after aortic arch clipped or sham surgery to deter-mine left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular posterior wall end-diastolic thickness (LVPWD), ejection fraction (EF) and fractional shortening (FS). After hemodynamic recordings were completed, mouse body weight (BW) and heart weight (HW) were measured for obtaining HW/BW ratio (mg/g). After heart function examination, mice blood sample was collected for evaluation of serum N-terminal pro-brain natriuretic peptide (NT-proBNP). At the end, part of left ventricular free wall was excised, and hematoxylin and eosin stain was made for histopathological examination. ResultsThe HW/BW, LVEDD and serum NT-proBNP significantly increased in the experiment group compared with those in the sham group (P < 0.01, respectively). The LVPWD, EF and FS significantly decreased compared with the sham group (P < 0.01, respectively). Histopathological examination showed malalignment and rupture of cardiac muscle fibers, hypertrophy and degeneration of myocardial cells, part of which had local or patchy necrosis in left ventricule postoperatively 10 weeks. ConclusionThe model of pressure overload-induced heart failure in mice established through suprasternal approach is simple, minimally invasive and reliable.
【Abstract】 Objective To investigate the effect of verapamil on apoptosis, calcium and expressions of bcl-2 and c-myc of pancreatic cells in ischemia-reperfusion rat model. Methods Wistar rats were randomly divided into three groups: control group （n=10）; ischemia-reperfusion group （n=10）; verapamil treatment group （n=10）. The anterior mesenteric artery and the celiac artery of rats in both ischemia-reperfusion group and verapamil treatment group were occluded for 15 min followed by 12-hour reperfusion. Verapamil （1 mg／kg） was injected via caudal vein to the rats in verapamil treatment group 15 min before occlusion and 1 hour after the initiation of reperfusion, respectively; and ischemia-reperfusion group was given the same volume of salient twice intravenously. Pancreatic tissues were collected from the dead rats after twelve hours since the reperfusion. The pathologic characters of pancreatic tissue were observed under light microscope; The level of calcium in the tissue was measured by atomic absorption spectrometer; TUNEL was used to detect apoptosis of pancreatic cells; and the expressions of c-myc and bcl-2 in the cells were also analyzed by immunohistochemistry technique and flow cytometry. Results The pathologic change in verapamil treatment group was less conspicuous than that of ischemia-reperfusion group. Both the calcium level and the number of apoptotic cells in verapamil treatment group were less than those of ischemia-reperfusion group 〔（411.1±55.8） μg/g dry weight vs （470.9±31.9） μg/g dry weight, P＜0.05 and （9.5±2.9）% vs （18.4±3.1）% 〕, P＜0.05. After taking verapamil, the number of apoptotic cells decreased, whereas the expressions of bcl-2 and c-myc increased. The fluorescent indexes of bcl-2 and c-myc in verapamil treatment group were significantly higher than those of ischemia-reperfusion group (1.72±0.11 vs 1.41±0.07, P＜0.05; 1.76±0.19 vs 1.55±0.13, P＜0.05. Conclusion Ischemia-reperfusion injury can induce apoptosis of pancreatic cells. Verapamil could protect the injured pancreatic tissue by reducing the level of calcium, stimulating the expressions of bcl-2 and c-myc and inhibiting apoptosis of pancreatic cells.
Objective To investigate the research progress of drug-loaded antibacterial coating of orthopedic metal implants in recent years. Methods The recent literature on the drug-loaded antibacterial coating of orthopedic metal implants were reviewed. The research status, classification, and development trend of drug-loaded antibacterial coating were summarized. Results The drug-loaded antibacterial coating of orthopedic metal implants can be divided into passive release type and active release type according to the mode of drug release. Passive drug release coating can release the drug continuously regardless of whether the presence of bacteria around the implants. Active drug release coating do not release the drug unless the presence of bacteria around the implants. Conclusion The sustained and stable release of drugs is a key problem to be solved in various antibacterial coatings research. The intelligent antibacterial coating which release antibiotics only in the presence of bacteria is the future direction of development.