Cell freeze-drying can be divided into the freezing and drying processes. Mechanical damage caused by ice crystals and damage from solute during freezing shall not be ignored and lyoprotectants are commonly used to reduce those damages on cells. In order to study the mechanism of lyoprotectants to protect cells and determine an optimal lyoprotectant formula, the thermophysical properties and percentage of unfrozen water of different lyoprotectants in freezing were investigated with differential scanning calorimeter (DSC). The survival rate indicated by trypan blue exclusion test and cell-attachment rate after 24 h using different lyoprotectants to freeze hepatoma Hep-G2 cells were measured after cell cryopreservation. The results show that 40% (W/V) PVP + 10% (V/V) glycerol + 15% (V/V) fetal bovine serum + 20% (W/V) trehalose formula of lyoprotectant demonstrate the best effect in protecting cells during freezing, for cell-attachment rate after 24 h is 44.56% ± 2.73%. In conclusion, the formula of lyoprotectant mentioned above can effectively protect cells.
Methylcellulose is a semi-flexible cellulose ether derivative, whose hydrogels are thermosensitive and reversible, with good biocompatibility and adjustable function, and its application has attracted much attention in the biomedical field. In this paper, the application of methylcellulose-based thermo-sensitive hydrogels in biomedical field was reviewed. Based on the mechanism of gelation and influencing factors of methylcellulose, this paper focused on the recent advances in biomedical applications of methylcellulose-based hydrogels, including drug delivery, regenerative medicine, and other related fields. The current achievements in these fields were summarized in the form of lists in this paper to provide ideas and tendencies for future research. Finally, the future development of multifunctional methylcellulose-based hydrogel materials with improved performance was also discussed.
The freeze-drying is a technology that preserves biological samples in a dry state, which is beneficial for storage, transportation, and cost saving. In this study, the bovine pericardium was treated with a freeze-drying protectant composed of polyethylene glycol (PEG) and trehalose (Tre), and then freeze-dried. The results demonstrated that the mechanical properties of the pericardium treated with PEG + 10% w/v Tre were superior to those of the pericardium fixed with glutaraldehyde (GA). The wet state water content of the rehydrated pericardium, determined using the Karl Fischer method, was (74.81 ± 1.44)%, which was comparable to that of the GA-fixed pericardium. The dry state water content was significantly reduced to (8.64 ± 1.52)%, indicating effective dehydration during the freeze-drying process. Differential scanning calorimetry (DSC) testing revealed that the thermal shrinkage temperature of the pericardium was (84.96 ± 0.49) ℃, higher than that of the GA-fixed pericardium (83.14 ± 0.11) ℃, indicating greater thermal stability. Fourier transform infrared spectroscopy (FTIR) results showed no damage to the protein structure during freeze-drying. Hematoxylin and eosin (HE) staining demonstrated that the freeze-drying process reduced pore formation, prevented ice crystal growth, and resulted in a tighter arrangement of tissue fibers. The frozen-dried bovine pericardium was subjected to tests for cell viability and hemolysis rate. The results revealed a cell proliferation rate of (77.87 ± 0.49)%, corresponding to a toxicity grade of 1. Additionally, the hemolysis rate was (0.17 ± 0.02)%, which is below the standard of 5%. These findings indicated that the frozen-dried bovine pericardium exhibited satisfactory performance in terms of cytotoxicity and hemolysis, thus meeting the relevant standards. In summary, the performance of the bovine pericardium treated with PEG + 10% w/v Tre and subjected to freeze-drying could meet the required standards.
Objective To investigate the role of β-catenin gene in breast tumorigenesis by detecting mutation and expression of β-catenin gene in breast hyperplasia and breast cancer. Methods Mutation and expression of β-catenin gene in 42 breast cancer, 15 simple hyperplasia and 15 atypical hyperplasia were detected by polymerase chain reaction-single strand conformation polymorphism and immunohistochemistry. Results Normal expression of β-catenin occurred in tissue of breast simple hyperplasia. The rate of abnormal expression of β-catenin in tissue of breast atypical hyperplasia and breast cancer were 26.7% （4/15） and 59.5% （25/42）, respectively, which were higher than that of simple hyherplasia tissue (P＜0.05). And there was a markedly difference between the atypical hyperplasia tissue and breast cancer tissue (P＜0.05). Mutation of β-catenin gene wasn’t detected in this three kinds of tissues. Conclusion Abnormal expression of β-catenin plays an important role in human breast tumorigenesis, reason of abnormal expression of β-catenin isn’t mutation of β-catenin gene. Expression of β-catenin can be regulated by other mechanisms.
Objective The survival data of patients with colon cancer who were treated by laparoscopic-assisted surgery and open surgery three years after operation were analyzed and contrasted, which provided data to support the future treatment. Methods The 217 patients who were cured by laparoscopic-assisted surgery and 193 patients who were cured by open surgery were followed up, and the rates of local recurrence, metastasis, implantative, and survival were contrasted and analyzed. Results Three years after laparoscopic-assisted surgery and open surgery, the disease-free survival rate was 86.2% （187/217） and 85.5% （165/193）, respectively, and the overall survival rate was 91.2% （198/217） and 92.7% （179/193）, respectively, the difference between the two groups was not statistic significance（P＞0.05）. The differences of the rates of local recurrence, metastasis, and implantative between the two groups were not statistic significance（P＞0.05）. Conclusions Laparoscopic-assisted surgery is similar with open surgery in the rates of local recurrence, forward metastasis, and overall survival. So laparoscopic-assisted surgery is a safe and radical curative surgery.
Objective To summarize the short-term efficacy， surgery complications， and relative experiences in the management of severe functional constipation （SFC） under laparoscopy-assisted subtotal colectomy combined modified Duhamel procedure. Methods All the data of 15 patients underwent laparoscopy-assisted subtotal colectomy combined modified Duhamel procedure from March 2010 to August 2011 were collected retrospectively， all the patients were diagnosed as SFC and failed to conservative therapy. The postoperative short-term efficacy， complications of surgery， score of gastrointestinal living condition， and improvement degree of defecation were analyzed. Results All 15 procedures achieved success， the operation time was （247.33±55.10） min， the intraoperative blood loss volume was （107.33±45.59） ml， the incision length was （8.40±2.41） cm， the postoperative out of bed activity time was （2.27±1.28） d，the postoperative passage of gas by anus time was （2.60±1.89） d， the postoperative defecation time was （2.87±2.50） d，the postoperative foods taken per oral time was （3.07±1.16） d， the hospital stay was （12.64±2.37） d. Approximately on day 3-4 after operation， 10 patients presented with postoperative diarrhea but were all under control with antidiarrheals efficiently. One patient presented with incomplete bowel obstruction on day 8 after operation and one patient with stomal leakage complicated with deep infection on day 9 after operation， who both recovered under conservative therapy. The scoreof gastrointestinal living quality on month 1 after operation was significantly higher than that on day 1 before operation （121.80±4.72 versus 90.80±7.24， P=0.000）， and the improvement degree of defecation was （0.81±0.56）%. Conclusions From the limited case informations， the laparoscopy-assisted subtotal colectomy combined modified Duhamel procedure has a certain short-term curative effect in treatment for SFC with the advantages of faster recovery， less bleeding， shorter hospital stay， and fewer complications.