PURPOSE: To investigate the protective effect of sub-hypothermic mechanical perfusion combined with membrane lung oxygenation on ischemic hypoxic injury of yorkshire brain tissue caused by traumatic blood loss. METHODS: This article performed a random controlled trial. Brain tissue of 7 yorkshire was selected and divided into the sub-low temperature anterograde machine perfusion group (n = 4) and the blank control group (n = 3) using the random number table method. A yorkshire model of brain tissue injury induced by traumatic blood loss was established. Firstly, the perfusion temperature and blood oxygen saturation were monitored in real-time during the perfusion process. The number of red blood cells, hemoglobin content, NA⁺, K⁺, and Ca²⁺ ions concentrations and pH of the perfusate were detected. Following perfusion, we specifically examined the parietal lobe to assess its water content. The prefrontal cortex and hippocampus were then dissected for histological evaluation, allowing us to investigate potential regional differences in tissue injury. The blank control group was sampled directly before perfusion. All statistical analyses and graphs were performed using GraphPad Prism 8.0 Student t-test. All tests were two-sided, and p value of less than 0.05 was considered to indicate statistical significance. RESULTS: The contents of red blood cells and hemoglobin during perfusion were maintained at normal levels but more red blood cells were destroyed 3 h after the perfusion. The blood oxygen saturation of the perfusion group was maintained at 95% - 98%. NA⁺ and K⁺ concentrations were normal most of the time during perfusion but increased significantly at about 4 h. The Ca²⁺ concentration remained within the normal range at each period. Glucose levels were slightly higher than the baseline level. The pH of the perfusion solution was slightly lower at the beginning of perfusion, and then gradually increased to the normal level. The water content of brain tissue in the sub-low and docile perfusion group was 78.95% ± 0.39%, which was significantly higher than that in the control group (75.27% ± 0.55%, t = 10.49, p < 0.001), and the difference was statistically significant. Compared with the blank control group, the structure and morphology of pyramidal neurons in the prefrontal cortex and CA1 region of the hippocampal gyrus were similar, and their integrity was better. The structural integrity of granulosa neurons was destroyed and cell edema increased in the perfusion group compared with the blank control group. Immunofluorescence staining for glail fibrillary acidic protein and Iba1, markers of glial cells, revealed well-preserved cell structures in the perfusion group. While there were indications of abnormal cellular activity, the analysis showed no significant difference in axon thickness or integrity compared to the 1-h blank control group. CONCLUSIONS Mild hypothermic machine perfusion can improve ischemia and hypoxia injury of yorkshire brain tissue caused by traumatic blood loss and delay the necrosis and apoptosis of yorkshire brain tissue by continuous oxygen supply, maintaining ion homeostasis and reducing tissue metabolism level.
Animals ; Perfusion/methods* ; Disease Models, Animal ; Brain Injuries/etiology* ; Swine ; Male ; Hypothermia, Induced/methods*

Objective:To compare the protective effects of the static cold storage (SCS) and normothermic machine perfusion (NMP) on the skeletal muscle of the amputated limbs of pigs.Methods:Four Landrace pigs were selected, from which eight limbs were amputated and divided into SCS group ( n=5) and NMP group ( n=3) according to the random number table method. After blood collection from the carotid artery, an amputated limb model was established by amputating the limbs at the scapulohumeral joints. The limbs in the SCS group were wrapped in sterile cloth and stored at 4 ℃ for 24 hours. In the NMP group, the limbs were mechanically perfused with a red blood cell-containing perfusion fluid at 37 ℃ for 24 hours, with 70% of the perfusion fluid replaced every 6 hours. Before the experiment, cross-matching tests with the saline medium were conducted between donor and recipient pigs to evaluate blood coagulation and blood safety in the NMP group. An allogeneic red blood cell perfusion fluid was prepared and the levels of pH, Na +, K +, Cl -, Ca 2+, glucose (Glu), hematocrit (Hct), lactic acid (Lac) and osmotic pressure of the perfusion fluid were measured. At 0, 6, 12, 18, and 24 hours after perfusion, the skin temperature and oxyhemoglobin saturation (SaO 2) levels in the NMP group were monitored and the levels of pH, Glu, creatine kinase (Ck), K +, Ca 2+, and Na +levels of the perfusion fluid were analyzed to evaluate the metabolism of the skeletal muscle in the amputated limbs. The mean intercellular distance and apoptosis index of the myocytes were quantitatively analyzed and histopathological changes were observed by performing HE staining and TUNEL staining on the skeletal muscle of the amputated limbs in both groups at 0 and 24 hours after perfusion. After perfusion was ended, the weight gain rate and swelling degree of the amputated limbs were compared between the two groups and the overall state of the amputated limbs was evaluated. Results:The result of the cross-matching test between donor and recipient pig blood was negative. The parameters in the prepared red blood cell-containing perfusion fluid generally maintained within a normal range: pH 7.38±0.04, Na + concentration (138.30±4.48)mmol/L, K + concentration (3.50±0.26)mmol/L, Glu concentration (6.11±2.08)mmol/L, and osmotic pressure (305.67±3.79)mmol/L. However, slightly higher Cl - and Ca 2+ concentrations [(118.34±12.00)mmol/L and (2.00±0.15)mmol/L] and lower Hct and lactate concentrations [0.30±0.03 and (1.54±0.38)mmol/L] were detected when compared with the reference range. During the perfusion, the average skin temperature of the amputated limbs in the NMP group was (36.13±0.98)℃, with the skin temperatures at 6, 12, 18, and 24 hours after perfusion being significantly higher than that at 0 hour ( P<0.01), while no significant difference among the skin temperatures at 6, 12, 18, and 24 hours after perfusion was observed ( P>0.05). The SaO 2 levels in the skin of the amputated limbs in the NMP group averaged over 95%, which showed no significant difference at 0, 12, 18, and 24 hours after perfusion ( P>0.05), while a significant elevation was observed at 6 hours compared with that at 0 hour ( P<0.05). There were no significant differences in pH, Glu, Na +, and Ca 2+ levels in the NMP group at 0, 6, 12, 18, and 24 hours after perfusion ( P>0.05), while the Ck levels at 18 and 24 hours were both significantly higher than that at 6 hours after perfusion ( P<0.05), and the Ck levels at 6, 12, 18, and 24 hours were all significantly higher than that at 0 hour ( P<0.05). The K + level progressively increased with the perfusion time, with significant elevations at 18 and 24 hours after perfusion compared with that at 0 hour ( P<0.05). HE staining revealed well-preserved muscle fiber continuity and regular arrangement in the NMP group and the SCS group at 0 hour, with an intercellular distance of (8.95±0.60)μm. At 24 hours, the NMP group exhibited slight skeletal muscle fiber rupture and swelling, with a slightly increased intercellular distance of (14.75±0.90)μm, significantly greater than that at 0 hour ( P<0.01). At 24 hours, the SCS group showed marked skeletal muscle fiber rupture and swelling, with a significantly increased intercellular distance of (23.51±1.49)μm, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). TUNEL immunofluorescence staining indicated a tiny amount of apoptotic cells in the skeletal muscle in both groups at 0 hour, with an apoptotic index of (4.26±1.62)%. There was a small number of apoptotic cells in the skeletal muscle in the NMP group at 24 hours, with an apoptotic index of (25.94±2.69)%, significantly larger than that in the same group at 0 hour ( P<0.01). The SCS group exhibited a large number of apoptotic cells at 24 hours, with an apoptotic index of (62.97±3.22)%, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). In comparison with the SCS group at 24 hours, the amputated limbs in the NMP group showed red color in the appearance, no symptoms of ischemic muscle contracture and good joint movement despite slight edema in the subcutaneous layer. At 24 hours, the weight gain rate of the amputated limbs was (15.82±0.89)% in the NMP group, significantly higher than (0.97±0.28)% in the SCS group ( P<0.01). Conclusion:Compared with SCS, NMP with the red blood cell-containing perfusion fluid prepared with the allogeneic blood for the amputated limbs of pigs can alleviate the ischemic injury of the muscle fibers and inhibit the apoptosis of the muscle cells by sustaining stable energy and oxygen supply and balancing ion homeostasis and pH of the perfusion fluid.

Objective:To compare the clinical effects of restrictive transfusion strategy and liberal transfusion strategy for cardiac valve surgery.Methods:This study employed a prospective, randomized controlled superiority design, enrolling 439 patients undergoing non-emergency cardiac valve surgery with cardiopulmonary bypass at Department of Cardiovascular Surgery, Guangdong Provincial People′s Hospital, Southern Medical University from June 2023 to October 2024 who met the inclusion and exclusion criteria. While all the patients appeared hematocrit (Hct)≤24% or hemoglobin (Hb)≤80 g/L during the cardiopulmonary bypass. A simple random design was adopted to generate a random sequence and participants were randomized into a restrictive transfusion group (restrictive criteria: Hct≤18% or Hb≤60 g/L during cardiopulmonary bypass, and Hct≤21% or Hb≤70 g/L postoperatively) or a liberal transfusion group (liberal criteria: Hct≤24% or Hb≤80 g/L during cardiopulmonary bypass and Hct≤30% or Hb≤100 g/L postoperatively). If Hb or Hct fell below the respective thresholds, 2 units of red blood cells were transfused, followed by re-evaluation. If levels remained below the threshold, an additional 2 units were transfused until the criteria were met. The primary outcome was a composite of postoperative 3-month mortality, infection, ischemic events, and new-onset renal failure requiring dialysis. Secondary outcomes included blood product utilization, length of stay in the ICU and so on. Intergroup comparisons were performed using independent sample t-test, Mann-Whitney U test, χ2 test, or Fisher′s exact test, and analyses were conducted using a binary multivariable Logistic regression model. Results:A total of 439 patients were included in this study. The restrictive roup included 221 patients, including 75 males and 146 females, aged ( M(IQR)) 57.0 (14.0) years (range: 21 to 76 years). The liberal group included 218 patients, including 67 males and 151 females, aged 56.0 (20.0) years (range: 19 to 74 years). No statistically significant difference was observed in the incidence of primary outcome (restrictive group: 10.9%(24/221) vs. liberal group: 9.6%(21/218), χ2=0.180, P>0.05), 2 patints in the restrictive group died and 3 patints in liberal group died ( P=0.684). The transfusion rate was significantly lower in the restrictive group(19.0%(42/221) vs. 100%(218/218), P<0.01), with no significant differences in other secondary outcomes (all P>0.05). Subgroup analysis revealed an interaction between sex and transfusion strategy ( P=0.023), suggesting that using liberal transfusion strategy in male patients might increase the risk of the primary outcome. Conclusion:The mid-term results do not show that the restrictive transfusion strategy is superior to the liberal transfusion strategy in reducing the incidence of postoperative outcome events in patients undergoing cardiac valve surgery.

Objective:To compare the protective effects of the static cold storage (SCS) and normothermic machine perfusion (NMP) on the skeletal muscle of the amputated limbs of pigs.Methods:Four Landrace pigs were selected, from which eight limbs were amputated and divided into SCS group ( n=5) and NMP group ( n=3) according to the random number table method. After blood collection from the carotid artery, an amputated limb model was established by amputating the limbs at the scapulohumeral joints. The limbs in the SCS group were wrapped in sterile cloth and stored at 4 ℃ for 24 hours. In the NMP group, the limbs were mechanically perfused with a red blood cell-containing perfusion fluid at 37 ℃ for 24 hours, with 70% of the perfusion fluid replaced every 6 hours. Before the experiment, cross-matching tests with the saline medium were conducted between donor and recipient pigs to evaluate blood coagulation and blood safety in the NMP group. An allogeneic red blood cell perfusion fluid was prepared and the levels of pH, Na +, K +, Cl -, Ca 2+, glucose (Glu), hematocrit (Hct), lactic acid (Lac) and osmotic pressure of the perfusion fluid were measured. At 0, 6, 12, 18, and 24 hours after perfusion, the skin temperature and oxyhemoglobin saturation (SaO 2) levels in the NMP group were monitored and the levels of pH, Glu, creatine kinase (Ck), K +, Ca 2+, and Na +levels of the perfusion fluid were analyzed to evaluate the metabolism of the skeletal muscle in the amputated limbs. The mean intercellular distance and apoptosis index of the myocytes were quantitatively analyzed and histopathological changes were observed by performing HE staining and TUNEL staining on the skeletal muscle of the amputated limbs in both groups at 0 and 24 hours after perfusion. After perfusion was ended, the weight gain rate and swelling degree of the amputated limbs were compared between the two groups and the overall state of the amputated limbs was evaluated. Results:The result of the cross-matching test between donor and recipient pig blood was negative. The parameters in the prepared red blood cell-containing perfusion fluid generally maintained within a normal range: pH 7.38±0.04, Na + concentration (138.30±4.48)mmol/L, K + concentration (3.50±0.26)mmol/L, Glu concentration (6.11±2.08)mmol/L, and osmotic pressure (305.67±3.79)mmol/L. However, slightly higher Cl - and Ca 2+ concentrations [(118.34±12.00)mmol/L and (2.00±0.15)mmol/L] and lower Hct and lactate concentrations [0.30±0.03 and (1.54±0.38)mmol/L] were detected when compared with the reference range. During the perfusion, the average skin temperature of the amputated limbs in the NMP group was (36.13±0.98)℃, with the skin temperatures at 6, 12, 18, and 24 hours after perfusion being significantly higher than that at 0 hour ( P<0.01), while no significant difference among the skin temperatures at 6, 12, 18, and 24 hours after perfusion was observed ( P>0.05). The SaO 2 levels in the skin of the amputated limbs in the NMP group averaged over 95%, which showed no significant difference at 0, 12, 18, and 24 hours after perfusion ( P>0.05), while a significant elevation was observed at 6 hours compared with that at 0 hour ( P<0.05). There were no significant differences in pH, Glu, Na +, and Ca 2+ levels in the NMP group at 0, 6, 12, 18, and 24 hours after perfusion ( P>0.05), while the Ck levels at 18 and 24 hours were both significantly higher than that at 6 hours after perfusion ( P<0.05), and the Ck levels at 6, 12, 18, and 24 hours were all significantly higher than that at 0 hour ( P<0.05). The K + level progressively increased with the perfusion time, with significant elevations at 18 and 24 hours after perfusion compared with that at 0 hour ( P<0.05). HE staining revealed well-preserved muscle fiber continuity and regular arrangement in the NMP group and the SCS group at 0 hour, with an intercellular distance of (8.95±0.60)μm. At 24 hours, the NMP group exhibited slight skeletal muscle fiber rupture and swelling, with a slightly increased intercellular distance of (14.75±0.90)μm, significantly greater than that at 0 hour ( P<0.01). At 24 hours, the SCS group showed marked skeletal muscle fiber rupture and swelling, with a significantly increased intercellular distance of (23.51±1.49)μm, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). TUNEL immunofluorescence staining indicated a tiny amount of apoptotic cells in the skeletal muscle in both groups at 0 hour, with an apoptotic index of (4.26±1.62)%. There was a small number of apoptotic cells in the skeletal muscle in the NMP group at 24 hours, with an apoptotic index of (25.94±2.69)%, significantly larger than that in the same group at 0 hour ( P<0.01). The SCS group exhibited a large number of apoptotic cells at 24 hours, with an apoptotic index of (62.97±3.22)%, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). In comparison with the SCS group at 24 hours, the amputated limbs in the NMP group showed red color in the appearance, no symptoms of ischemic muscle contracture and good joint movement despite slight edema in the subcutaneous layer. At 24 hours, the weight gain rate of the amputated limbs was (15.82±0.89)% in the NMP group, significantly higher than (0.97±0.28)% in the SCS group ( P<0.01). Conclusion:Compared with SCS, NMP with the red blood cell-containing perfusion fluid prepared with the allogeneic blood for the amputated limbs of pigs can alleviate the ischemic injury of the muscle fibers and inhibit the apoptosis of the muscle cells by sustaining stable energy and oxygen supply and balancing ion homeostasis and pH of the perfusion fluid.

Objective:To compare the clinical effects of restrictive transfusion strategy and liberal transfusion strategy for cardiac valve surgery.Methods:This study employed a prospective, randomized controlled superiority design, enrolling 439 patients undergoing non-emergency cardiac valve surgery with cardiopulmonary bypass at Department of Cardiovascular Surgery, Guangdong Provincial People′s Hospital, Southern Medical University from June 2023 to October 2024 who met the inclusion and exclusion criteria. While all the patients appeared hematocrit (Hct)≤24% or hemoglobin (Hb)≤80 g/L during the cardiopulmonary bypass. A simple random design was adopted to generate a random sequence and participants were randomized into a restrictive transfusion group (restrictive criteria: Hct≤18% or Hb≤60 g/L during cardiopulmonary bypass, and Hct≤21% or Hb≤70 g/L postoperatively) or a liberal transfusion group (liberal criteria: Hct≤24% or Hb≤80 g/L during cardiopulmonary bypass and Hct≤30% or Hb≤100 g/L postoperatively). If Hb or Hct fell below the respective thresholds, 2 units of red blood cells were transfused, followed by re-evaluation. If levels remained below the threshold, an additional 2 units were transfused until the criteria were met. The primary outcome was a composite of postoperative 3-month mortality, infection, ischemic events, and new-onset renal failure requiring dialysis. Secondary outcomes included blood product utilization, length of stay in the ICU and so on. Intergroup comparisons were performed using independent sample t-test, Mann-Whitney U test, χ2 test, or Fisher′s exact test, and analyses were conducted using a binary multivariable Logistic regression model. Results:A total of 439 patients were included in this study. The restrictive roup included 221 patients, including 75 males and 146 females, aged ( M(IQR)) 57.0 (14.0) years (range: 21 to 76 years). The liberal group included 218 patients, including 67 males and 151 females, aged 56.0 (20.0) years (range: 19 to 74 years). No statistically significant difference was observed in the incidence of primary outcome (restrictive group: 10.9%(24/221) vs. liberal group: 9.6%(21/218), χ2=0.180, P>0.05), 2 patints in the restrictive group died and 3 patints in liberal group died ( P=0.684). The transfusion rate was significantly lower in the restrictive group(19.0%(42/221) vs. 100%(218/218), P<0.01), with no significant differences in other secondary outcomes (all P>0.05). Subgroup analysis revealed an interaction between sex and transfusion strategy ( P=0.023), suggesting that using liberal transfusion strategy in male patients might increase the risk of the primary outcome. Conclusion:The mid-term results do not show that the restrictive transfusion strategy is superior to the liberal transfusion strategy in reducing the incidence of postoperative outcome events in patients undergoing cardiac valve surgery.

Objective To analyze the influencing factors of survival of patients with airway stenosis requiring clinical interventions after lung transplantation. Methods Clinical data of 66 patients with airway stenosis requiring clinical interventions after lung transplantation were retrospectively analyzed. Univariate and multivariate Cox’s regression models were adopted to analyze the influencing factors of survival of all patients with airway stenosis and those with early airway stenosis. Kaplan-Meier method was used to calculate the overall survival and delineate the survival curve. Results For 66 patients with airway stenosis, the median airway stenosis-free time was 72 (52,102) d, 27% (18/66) for central airway stenosis and 73% (48/66) for distal airway stenosis. Postoperative mechanical ventilation time [hazard ratio (HR) 1.037, 95% confidence interval (CI) 1.005-1.070, P=0.024] and type of surgery (HR 0.400, 95%CI 0.177-0.903, P=0.027) were correlated with the survival of patients with airway stenosis after lung transplantation. The longer the postoperative mechanical ventilation time, the higher the risk of mortality of the recipients. The overall survival of airway stenosis recipients undergoing bilateral lung transplantation was better than that of their counterparts after single lung transplantation. Subgroup analysis showed that grade 3 primary graft dysfunction (PGD) (HR 4.577, 95%CI 1.439-14.555, P=0.010) and immunosuppressive drugs (HR 0.079, 95%CI 0.022-0.287, P<0.001) were associated with the survival of patients with early airway stenosis after lung transplantation. The overall survival of patients with early airway stenosis after lung transplantation without grade 3 PGD was better compared with that of those with grade 3 PGD. The overall survival of patients with early airway stenosis after lung transplantation treated with tacrolimus was superior to that of their counterparts treated with cyclosporine. Conclusions Long postoperative mechanical ventilation time, single lung transplantation, grade 3 PGD and use of cyclosporine may affect the survival of patients with airway stenosis after lung transplantation.

Objective To evaluate the preservation effect of normothermic mechanical perfusion with red blood cells from humanized genetically modified pig on severed human limbs.Methods Severed human limbs were perfused with red blood cells from humanized genetically modified pigs for 6 h.Perfusion solution was taken every hour to measure the oxygen partial pressure,Na+,K+,Ca2+,pH value,glucose,lactic acid and creatine kinase levels.Superficial flexor muscle was sampled to detect the changes of tumor necrosis factor(TNF)-α,interleukin(IL)-2 and IL-1 levels.At 0 and 6 h after perfusion,the superficial flexor muscles of the forearm were taken for pathological examination.Intercellular space and glycogen consumption of skeletal muscles were observed.An appropriate amount of forearm vessels was collected every 2 h to detect the apoptosis of vascular endothelial cells.X-ray angiography was performed before perfusion and 6 h after perfusion to observe the filling degree of finger-tip peripheral vessels.Results The oxygen partial pressure was observed in the normal range throughout the perfusion.Na+concentration peaked at 1 h,reaching 138.7 mmol/L,and then fluctuated within the normal range.K+level peaked at 2 h up to 6.08 mmol/L,then decreased and fluctuated within the normal range.Ca2+concentration reached the peak at 4 h,up to 1.03 mmol/L.Glucose level was gradually decreased at the beginning of perfusion,reaching the lowest value of 17.7 mmol/L at 2 h after perfusion,and then maintained a dynamic balance.The pH value was decreased to 7.28 at 6 h after perfusion.The lactic acid level was increased to 9.6 mmol/L at 1 h after perfusion,and then gradually decreased.The creatine kinase level was increased at the start of perfusion,reached the peak at 2 h up to 20 030 U/L,then decreased and remained stable at the end of perfusion.At the end of perfusion,the morphology of muscle fibers was normal,the gap among muscle fibers was expanded slightly,and the glycogen of skeletal muscles was not significantly accumulated.At 0 h perfusion,the number of apoptotic cells in vascular endothelial cells was large,which was declined at 6 h perfusion.Evident vascular filling was observed at 0 h,and the filling degree of some finger-tip vessels was decreased at 6 h.Conclusions Normothermic mechanical perfusion of severed human limbs with red blood cells from humanized genetically modified pigs may continuously and stably supply energy and oxygen,adjust the ion pH balance of perfusion solution,maintain normal cellular metabolism and exerts certain protective effect upon severed human limbs.

Objective:To search,evaluate and summarize the best evidence about nasal mucosa pressure injury caused by nasal feeding tube at home and abroad,and provide evidence-based basis for clinical practice.Methods:According to the"6S"model of evidence resources,literatures related to nasal mucosal stress injury were systematically searched from UpToDate,Guidelines International Network,Joanna Briggs Institute Evidence-based Healthcare Center,Web of Science,Cochrane Library,CNKI,Wanfang database and other related nutrition professional websites.The search period was from the establishment of the database to February 2024.Four researchers independently evaluated the literature quality,and after consulting the opinions of evidence-based experts,evidence was extracted and summarized for literatures that met the quality standards.Results:A total of 12 studies were included,including 5 guidelines,4 expert consensus,1 clinical decision,1 systematic review and 1 evidence summary,covering 24 pieces of evidence on 5 topics,including team building,nasal mucosa evaluation,nasal mucosa care,placement and maintenance of nasal feeding tube,monitoring and education.Conclusions:The evidence of prevention and nursing of nasal mucosal pressure injury caused by nasal feeding tube can be applied to clinical practice,promote the standardized management of nasal feeding tube and improve the implementation effect of enteral nutrition.

Objective To modify the mouse model of orthotopic left lung transplantation from different perspectives, aiming to establish a simpler, faster and stabler mouse model of lung transplantation. Methods Based on preliminary modified rat model of orthotopic left lung transplantation established by our team, varying extent of modifications were made regarding the tracheal intubation, cannula preparation and anastomosis procedures of orthotopic left lung transplantation in the recipient mice. Orthotopic left lung transplantation in 40 mice were performed by an operator with microsurgical experience. The dissection of the recipient's hilar structure was carried out at the plane of the hilar clamp model within the reverse-view, and the three branches (left main bronchus, pulmonary artery and pulmonary vein) of the pulmonary hilum were anastomosed in turn by the "pendulum" anastomosis method. The operation time of each procedure was recorded. The recipient mice were sacrificed at postoperative 2 weeks, and the incidence of postoperative complications was recorded. Results Lung transplantation was successfully completed in 40 mice, with no bronchial and vascular tearing or twisting, and no bleeding at the anastomosis site. The overall cardiopulmonary procurement time was (10.7±1.5) min, cannula preparation time was (16.2±1.5) min, cold ischemia time was (25.1±2.4) min, warm ischemia time was (19.4±1.6) min, and the total operation time was (57.2±2.9) min, respectively. During the follow-up from 6 to 14 days after surgery, one recipient mouse died of pleural effusion, probably caused by infection. No pneumothorax, thrombosis or atelectasis was found in the remaining recipient mice during postoperative follow-up. Conclusions The modified mouse model of orthotopic left lung transplantation based on "pendulum" anastomosis of the reverse-view plane possesses multiple advantages of short operation time, high success rate and few complications, which is expected to become an alternative model of studying pathological changes after lung transplantation and worthy of further application.

Objective: To investigate the representability and etiological diagnostic value of myocardium samples obtained from patients with hypertrophic cardiomyopathy (HCM) by transthoracic echocardiography-guided percutaneous intramyocardial septal biopsy (myocardial biopsy of Liwen procedure). Methods: This study was a retrospective case-series analysis. Patients with HCM, who underwent myocardial biopsy of Liwen procedure and radiofrequency ablation in Xijing Hospital, Air Force Military Medical University from July to December 2019, were included. Demographic data (age, sex), echocardiographic data and complications were collected through electronic medical record system. The histological and echocardiographic features, pathological characteristics of the biopsied myocardium of the patients were analyzed. Results: A total of 21 patients (aged (51.2±14.5) years and 13 males (61.9%)) were enrolled. The thickness of ventricular septum was (23.3±4.5)mm and the left ventricular outflow tract gradient was (78.8±42.6)mmHg (1 mmHg=0.133 kPa). Eight patients (38.1%) were complicated with hypertension, 1 patient (4.8%) had diabetes, and 2 patients (9.5%) had atrial fibrillation. Hematoxylin-eosin staining of myocardial samples of HCM patients before radiofrequency ablation evidenced myocytes hypertrophy, myocytes disarray, nuclear hyperchromatism, hypertrophy, atypia, coronary microvessel abnormalities, adipocyte infiltration, inflammatory cell infiltration, cytoplasmic vacuoles, lipofuscin deposition. Interstitial fibrosis and replacement fibrosis were detected in Masson stained biopsy samples. Hematoxylin-eosin staining of myocardial samples of HCM patients after radiofrequency ablation showed significantly reduced myocytes, cracked nuclear in myocytes, coagulative necrosis, border disappearance and nuclear fragmentation. Quantitative analysis of myocardial specimens of HCM patients before radiofrequency ablation showed that there were 9 cases (42.9%) with mild myocardial hypertrophy and 12 cases (57.1%) with severe myocardial hypertrophy. Mild, moderate and severe fibrosis were 5 (23.8%), 9 (42.9%) and 7 (33.3%), respectively. Six cases (28.6%) had myocytes disarray. There were 11 cases (52.4%) of coronary microvessel abnormalities, 4 cases (19.0%) of adipocyte infiltration, 2 cases (9.5%) of inflammatory cell infiltration,6 cases (28.5%) of cytoplasmic vacuole, 16 cases (76.2%) of lipofuscin deposition. The diameter of cardiac myocytes was (25.2±2.8)μm, and the percentage of collagen fiber area was 5.2%(3.0%, 14.6%). One patient had severe replacement fibrosis in the myocardium, with a fibrotic area of 67.0%. The rest of the patients had interstitial fibrosis. The myocardial specimens of 13 patients were examined by transmission electron microscopy. All showed increased myofibrils, and 9 cases had disorder of myofibrils. All patients had irregular shape of myocardial nucleus, partial depression, mild mitochondrial swelling, fracture and reduction of mitochondrial crest, and local aggregation of myofibrillary interfascicles. One patient had hypertrophy of cardiomyocytes, but the arrangement of muscle fibers was roughly normal. There were vacuoles in the cytoplasm, and Periodic acid-Schiff staining was positive. Transmission electron microscopy showed large range of glycogen deposition in the cytoplasm, with occasional double membrane surround, which was highly indicative of glycogen storage disease. No deposition of glycolipid substance in lysozyme was observed under transmission electron microscope in all myocardial specimens, which could basically eliminate Fabry disease. No apple green substance was found under polarized light after Congo red staining, which could basically exclude cardiac amyloidosis. Conclusion: Myocardium biopsied samples obtained by Liwen procedure of HCM patients are representative and helpful for the etiological diagnosis of HCM.
Biopsy/adverse effects* ; Cardiomegaly/pathology* ; Cardiomyopathy, Hypertrophic/diagnosis* ; Eosine Yellowish-(YS) ; Fibrosis ; Heart Defects, Congenital ; Hematoxylin ; Humans ; Lipofuscin ; Male ; Myocardium/pathology* ; Retrospective Studies