Objective To evaluate the safety and efficacy of a self-developed micro-normothermic machine perfusion (NMP) system (micro-perfusion device) for preserving isolated porcine limbs. Methods Five healthy Landrace pigs were selected, and their left and right forelimbs were randomly divided into the NMP group and static cold storage (SCS) group. The NMP group was perfused with the self-developed micro-perfusion device and polymerized hemoglobin perfusate for 32 hours at normothermia, while the SCS group was preserved at 4 ℃. Hemodynamic parameters such as perfusion pressure and flow were monitored. The pH value, partial pressure of oxygen (PO₂), lactic acid (Lac), creatine kinase (CK) and lactate dehydrogenase (LDH) in the perfusate were measured. Hematoxylin-eosin staining was used to assess the muscle tissue structure, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was employed to evaluate muscle cell apoptosis, and immunohistochemistry staining was applied to detect the expressions of tumor necrosis factor (TNF)-α and interleukin (IL)-6. A mixed-effects model was used to analyze the effects of time and treatment methods on tissue structure, cell apoptosis and inflammatory factors. Results The device could stably maintain a perfusion pressure of (69±15) mmHg and a flow rate of (117±42) mL/min. The pH value and electrolytes of the perfusate were generally stable, with PO₂ maintained at a high level. Lac was maintained at 5.38(3.81, 6.45) mmol/L, while CK and LDH increased over time. After 32 hours of perfusion in the NMP group, both the myocyte spacing and apoptosis rate were better than those in the SCS group. Mixed-effects model analysis showed that there were statistically significant differences in the effects of NMP treatment and SCS treatment on myocyte spacing and apoptosis rate per unit time (both P < 0.05). There were no statistically significant differences in TNF-α and IL-6 between the two groups, and mixed-effects model analysis showed no statistically significant differences in the effects of NMP treatment and SCS treatment on TNF-α and IL-6 per unit time (both P > 0.05). Conclusions The micro-perfusion device used in this study may achieve 32-hour normothermic preservation in a porcine limb amputation model, maintain basic metabolism and ionic homeostasis, reduce muscle structural damage and cell apoptosis without inducing additional inflammatory responses. This technology is expected to significantly extend the time window for replantation of amputated limbs in disaster rescue and long-distance transportation, providing an important technical basis for clinical translation and subsequent replantation research.

Objective To systematically evaluate the similarities between six-gene-modified pig red blood cells and human red blood cells in multiple dimensions, including cell morphology, hematological parameters, microbial safety and serological compatibility, and to verify the feasibility of using six-gene-modified pig red blood cells as an alternative for blood transfusion in cases of traumatic hemorrhage. Methods Blood samples from O-type human donor, six-gene-modified O-type pig and wild-type O-type pig were collected. The pig gene-modified phenotype was identified by flow cytometry. The morphology was observed using field emission scanning electron microscopy and the diameter was measured. Hematological tests, including blood routine, osmotic fragility test, adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) content and partial pressure of oxygen at 50% hemoglobin saturation (P50), were conducted to assess the deformability of red blood cells. Real-time fluorescent quantitative polymerase chain reaction was used to screen for zoonotic viruses, and cross-matching was performed using column gel method, condensation amine method and saline tube method. Results The six-gene-modified pig red blood cells successfully knocked out the α-Gal, Neu5Gc and Sda antigens and expressed hCD55. Wild-type pig red blood cells expressed these three antigens but did not express human complement regulatory proteins. All three types of red blood cells presented a biconcave discoid morphology. The diameter of O-type human red blood cells was larger than that of the six-gene-modified porcine red blood cells and wild-type pig red blood cells (all P < 0.05). The average red blood cell volume and average red blood cell hemoglobin of O-type humans were higher than those of the six-gene-modified pig red blood cells, and the distribution width-variable coefficient of O-type human red blood cells was lower than that of the six-gene-modified pig red blood cells (all P < 0.05). There were no statistically significant differences in the permeability fragility, ATP content, 2,3-DPG content, P50 and red blood cell deformability indicators of the three types of red blood cells (all P > 0.05). The screening for zoonotic viruses in human and animal cells of the six-gene-modified pigs and wild-type pigs was negative. The cross-matching results showed that in the column gel method and condensation amine method, the primary and secondary sides of the six-gene-modified pig red blood cells did not agglutinate with human red blood cells, while the wild-type pig red blood cells agglutinated with human red blood cells in all cross-matching methods. Conclusions The six-gene-modified pig red blood cells are highly similar to human red blood cells in terms of morphology, key hematological parameters, energy metabolism, oxygen-carrying capacity, mechanical properties, microbial safety and serological compatibility, providing an experimental basis for the clinical transformation of xenotransfusion.

Objective To investigate the impact of phase Ⅱ cardiac rehabilitation on the rehabilitation needs and physical activity status of patients after coronary heart disease intervention.Methods A total of 90 patients with coronary heart disease who underwent percutaneous coronary intervention(PCI)in the Coronary Heart Disease Center of the hospital from August 2023 to August 2024 were selected as the research subjects.They were subjected to a 12-week standardized phase Ⅱ cardiac rehabilitation training.General data survey forms,cardiac rehabilitation scales,and the International Physical Activity Questionnaire were used for scale surveys to understand the patients' needs before and after rehabilitation and their weekly physical activity en-ergy expenditure.The cardiopulmonary exercise test gold standard,which reflects exercise capacity through three indicators-maximum oxygen uptake(VO2 max),anaerobic threshold(AT),and metabolic equivalents(MET),were used to compare the physical activity status before and after cardiac rehabilitation.Results Compared with before the implementation,after the implementation of cardiac rehabilitation,the autonomy score in-creased(21.36±1.85 vs.16.73±3.28),the process anxiety(12.60±3.87 vs.14.27±2.12)and outcome anxiety scores(2.31±1.76 vs.4.56±3.56)decreased,the level of low-intensity physical activity decreased[(2 711.62±1 487.09)min/week vs.(3 845.97±2 083.71)min/week],the levels of moderate-intensity[(1 314.67±783.54)min/week vs.(686.22±126.79)min/week],high-intensity[(1 861.33±798.27)min/week vs.(112.00±40.77)min/week],and total physical activity increased[(5 887.62±2 843.54)min/week vs.(4 644.19±2 287.16)min/week].The levels of VO2 max[(28.11±14.28)mL·min-1·kg-1 vs.(23.82±12.34)mL·min-1·kg-1],AT[(16.06±5.41)mL·min-1·kg-1 vs.(13.53±4.56)mL·min-1·kg-1],and MET[(6.89±1.59)mL·min-1·kg-1 vs.(5.78±1.21)mL·min-1·kg-1]all in-creased,with statistically significant differences(P＜0.05).Conclusion Phase Ⅱ rehabilitation after PCI can effectively improve patients' physical activity levels.

Objective:To investigate the characteristics of gut microbiota distribution in children with cyclic vomiting syndrome（CVS）complicated by constipation.Methods:The children with CVS, aged from 1 to 16 years, who were admitted to Beijing Tsinghua Changgung Hospital from June 2022 to January 2024, were divided into constipation group and normal group(non-constipation group) according to whether they were complicated with constipation or not.The clinical data and stool samples of children were collect. The abundance, diversity and composition of intestinal flora in fecal samples of two groups were detected by metagenomics sequencing.Results:A total of 20 children with CVS were collected, including 10 patients in constipation group and 10 patients in normal group.There were no significant differences in general demographic data between the two groups, including age at admission, age at first onset, body mass index, gender distribution, disease severity, endoscopic findings, and abdominal pain patterns.Microbiome analysis yielded 470 operational taxonomic units (OTUs), with 414 OTUs identified in normal group and 56 OTUs in constipation group. The abundance and diversity of intestinal flora in constipation group were significantly lower than those in normal group. Principal coordinate analysis and principal component analysis indicated significant structural differences in gut microbiota composition between the two groups. LEfSe analysis revealed distinct taxonomic patterns between the two groups, with the normal group demonstrating predominant representation of Firmicutes at the phylum level, while the constipation group showed higher relative abundance of Bacteroidetes and Actinobacteria. KEGG pathway analysis revealed that the carbon metabolism pathways was significantly enriched in the constipation group.Conclusion:There are significant differences in intestinal flora between CVS children with and without comorbid constipation.Bacteroides and Actinomycetes play an important role in constipation of children with CVS. The diversity and metabolic function of intestinal flora may be one of the pathological mechanisms of CVS complicated with constipation.

Objective To explore the protective effects of genetically modified porcine erythrocyte suspension as a subnormothermic normoxic mechanical perfusate on hypoxic-ischemic brain injury in cynomolgus monkeys caused by traumatic hemorrhage.Methods Cynomolgus monkeys were randomly divided into positive and negative control groups(a total of 3 monkeys,with 3 left cerebral hemispheres as the positive control group and 3 right cerebral hemispheres as the negative control group)and the subnormothermic perfusion group(n=3).The positive control group was directly sampled 1 hour after circulatory arrest,while the negative control group was placed at subnormothermic conditions for 6 hours after circulatory arrest.The subnormothermic perfusion group underwent 6 hours of subnormothermic normoxic mechanical perfusion of the bilateral common carotid arteries of the cynomolgus monkey hypoxic-ischemic brain injury model using genetically modified porcine erythrocyte suspension 1 hour after circulatory arrest.Before perfusion,cross-matching experiments were conducted between the six genetically modified pig and the cynomolgus monkeys.After the start of perfusion,the levels of routine blood indicators in the perfusate were detected at 0,1,2,3,4,5 and 6 hours.Blood oxygen saturation was recorded,and the levels of Na+,K+,Ca2+,glucose and blood pH in the perfusate were measured,as well as the levels of IgG and IgM in the perfusate.After 6 hours of perfusion,the water content of the brain tissue was measured.Nissl staining was performed on the frontal cortex and hippocampal regions,and immunofluorescence staining was used to detect the expression of glial fibrillary acidic protein(GFAP),ionized calcium-binding adapter molecule 1(Iba1)and neuronal nuclear antigen(NEUN).Results The cross-matching results between the six genetically modified pig and the cynomolgus monkeys were negative.The number of red blood cells in the perfusate decreased significantly at 3 hours of perfusion,and the hemoglobin level showed a downward trend at 1,3,5 and 6 hours.The number of white blood cells and platelets decreased at all time points.The blood oxygen saturation in the subnormothermic perfusion group remained stable at 95%-98%,and the levels of blood oxygen saturation,Na+,Ca2+,glucose and pH were stable,while the K+level first increased and then decreased.There was no significant difference in the levels of IgG and IgM before and after perfusion.The water content of brain tissue at the end of perfusion in the subnormothermic perfusion group was significantly higher than that in the positive control group(P<0.001).Nissl staining results showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex of the subnormothermic perfusion group maintained better morphological integrity,with no significant increase in enlarged and deformed cells.In the hippocampal CA1 region,there was a slight increase in enlarged and deformed cells,and a few cells with undamaged structures showed reduced cell size.In the hippocampal dentate gyrus,fewer granule neurons had compromised structural integrity,with increased cell edema.NEUN immunofluorescence staining showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex and hippocampal CA1 region of the subnormothermic perfusion group had better morphological states,with clear axons.The granule cells in the hippocampal dentate gyrus were well preserved,but the nuclei were less well protected.GFAP immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had sparser protrusions that were more tightly associated with neurons.Iba1 immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had thicker and fewer protrusions.Conclusions Compared with the positive control group,subnormothermic normoxic mechanical perfusion with genetically modified porcine erythrocyte perfusate increases brain tissue edema in cynomolgus monkeys,but better preserves the morphological integrity of neurons and glial cells.The protective effects may be related to the continuous oxygen and energy supply,maintenance of ion homeostasis and perfusate pH,reduced rejection,and low metabolic state of the whole brain.

Objective:To investigate the characteristics of gut microbiota distribution in children with cyclic vomiting syndrome（CVS）complicated by constipation.Methods:The children with CVS, aged from 1 to 16 years, who were admitted to Beijing Tsinghua Changgung Hospital from June 2022 to January 2024, were divided into constipation group and normal group(non-constipation group) according to whether they were complicated with constipation or not.The clinical data and stool samples of children were collect. The abundance, diversity and composition of intestinal flora in fecal samples of two groups were detected by metagenomics sequencing.Results:A total of 20 children with CVS were collected, including 10 patients in constipation group and 10 patients in normal group.There were no significant differences in general demographic data between the two groups, including age at admission, age at first onset, body mass index, gender distribution, disease severity, endoscopic findings, and abdominal pain patterns.Microbiome analysis yielded 470 operational taxonomic units (OTUs), with 414 OTUs identified in normal group and 56 OTUs in constipation group. The abundance and diversity of intestinal flora in constipation group were significantly lower than those in normal group. Principal coordinate analysis and principal component analysis indicated significant structural differences in gut microbiota composition between the two groups. LEfSe analysis revealed distinct taxonomic patterns between the two groups, with the normal group demonstrating predominant representation of Firmicutes at the phylum level, while the constipation group showed higher relative abundance of Bacteroidetes and Actinobacteria. KEGG pathway analysis revealed that the carbon metabolism pathways was significantly enriched in the constipation group.Conclusion:There are significant differences in intestinal flora between CVS children with and without comorbid constipation.Bacteroides and Actinomycetes play an important role in constipation of children with CVS. The diversity and metabolic function of intestinal flora may be one of the pathological mechanisms of CVS complicated with constipation.

Objective To explore the protective effects of genetically modified porcine erythrocyte suspension as a subnormothermic normoxic mechanical perfusate on hypoxic-ischemic brain injury in cynomolgus monkeys caused by traumatic hemorrhage.Methods Cynomolgus monkeys were randomly divided into positive and negative control groups(a total of 3 monkeys,with 3 left cerebral hemispheres as the positive control group and 3 right cerebral hemispheres as the negative control group)and the subnormothermic perfusion group(n=3).The positive control group was directly sampled 1 hour after circulatory arrest,while the negative control group was placed at subnormothermic conditions for 6 hours after circulatory arrest.The subnormothermic perfusion group underwent 6 hours of subnormothermic normoxic mechanical perfusion of the bilateral common carotid arteries of the cynomolgus monkey hypoxic-ischemic brain injury model using genetically modified porcine erythrocyte suspension 1 hour after circulatory arrest.Before perfusion,cross-matching experiments were conducted between the six genetically modified pig and the cynomolgus monkeys.After the start of perfusion,the levels of routine blood indicators in the perfusate were detected at 0,1,2,3,4,5 and 6 hours.Blood oxygen saturation was recorded,and the levels of Na+,K+,Ca2+,glucose and blood pH in the perfusate were measured,as well as the levels of IgG and IgM in the perfusate.After 6 hours of perfusion,the water content of the brain tissue was measured.Nissl staining was performed on the frontal cortex and hippocampal regions,and immunofluorescence staining was used to detect the expression of glial fibrillary acidic protein(GFAP),ionized calcium-binding adapter molecule 1(Iba1)and neuronal nuclear antigen(NEUN).Results The cross-matching results between the six genetically modified pig and the cynomolgus monkeys were negative.The number of red blood cells in the perfusate decreased significantly at 3 hours of perfusion,and the hemoglobin level showed a downward trend at 1,3,5 and 6 hours.The number of white blood cells and platelets decreased at all time points.The blood oxygen saturation in the subnormothermic perfusion group remained stable at 95%-98%,and the levels of blood oxygen saturation,Na+,Ca2+,glucose and pH were stable,while the K+level first increased and then decreased.There was no significant difference in the levels of IgG and IgM before and after perfusion.The water content of brain tissue at the end of perfusion in the subnormothermic perfusion group was significantly higher than that in the positive control group(P<0.001).Nissl staining results showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex of the subnormothermic perfusion group maintained better morphological integrity,with no significant increase in enlarged and deformed cells.In the hippocampal CA1 region,there was a slight increase in enlarged and deformed cells,and a few cells with undamaged structures showed reduced cell size.In the hippocampal dentate gyrus,fewer granule neurons had compromised structural integrity,with increased cell edema.NEUN immunofluorescence staining showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex and hippocampal CA1 region of the subnormothermic perfusion group had better morphological states,with clear axons.The granule cells in the hippocampal dentate gyrus were well preserved,but the nuclei were less well protected.GFAP immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had sparser protrusions that were more tightly associated with neurons.Iba1 immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had thicker and fewer protrusions.Conclusions Compared with the positive control group,subnormothermic normoxic mechanical perfusion with genetically modified porcine erythrocyte perfusate increases brain tissue edema in cynomolgus monkeys,but better preserves the morphological integrity of neurons and glial cells.The protective effects may be related to the continuous oxygen and energy supply,maintenance of ion homeostasis and perfusate pH,reduced rejection,and low metabolic state of the whole brain.

Objective To investigate the multi spiral computed tomography(MSCT)characteristics and biological behaviors of advanced gastrointestinal signet ring cell carcinoma(SRCC),so as to provide accurate preoperative type,stage and personalized choice of treatment strategy in clinical practice.Methods The clinical manifestations,five tumor markers and MSCT imaging data of 26 cases(group A)with advanced gastrointestinal SRCC confirmed by surgical or endoscopic biopsy and pathological immunohistochemistry were analyzed retrospectively,and 44 cases(group B)of advanced non-signet ring cell carcinoma(NSRCC)during the same period were randomly selected as the control group.The clinical manifestations,five tumor markers and MSCT imaging features of groups A and B were analyzed.Results There were no significant differences in gender,tumor location,tumor thickness(T)and length(L),and five tumor markers between groups A and B(P＞0.05).There were significant differences in age,main symptoma,tumor thickness-to-length ratio(TLR),angle between cancerous edge and normal tissue(CNA)(P＜0.05).However,age of group A and group B[group A≤50 years old(12/26,46％),group B＞50 years old(42/44,95％)],main symptom(x2=19.085,P＜0.05),tumor TLR(Z=-2.044,P＜0.05)and CNA(x2=14.776,P＜0.05)were significantly different(P＜0.05).Conclusion SRCC affects younger patients and is more likely to originate from the middle and lower parts of the stomach and rectum,with lower TLR,obtuse angle of CNA,and"caterpillar-like"characteristics of colorectal SRCC.

Objective:To observe the protective effect of Panax notoginseng total saponins(PNS)on oxidative stress damage induced by hydrogen peroxide(H 2O 2)in human renal tubular epithelial cells(HK-2)and its mechanism. Methods:HK-2 was cultured and divided into experimental groups: Normal group(without any intervention factors), H 2O 2 group(400 μmol/L H 2O 2 was added into the cell culture system for 6 h)and PNS group(which was divided into three groups: PNS 25 μg/ml, 50 μg/ml and 100 μg/ml were added into the cell culture system for 4 h, and then 400 μmol/l H 2O 2 was added into the cell culture system for 6 h), and the apoptosis of HK-2 induced by H 2O 2 was observed. Results:Compared with the normal group, the cell survival rate of H 2O 2 group decreased to(45.67±2.52)% and the cell apoptosis rate increased to(19.23±1.63)%(all P<0.01), while the cell survival rate of PNS group was(55.12±2.33)%, (65.37±4.72)% and(83.46±1.52)%, and the apoptosis rate was reduced to(15.53±0.70)%, (12.53±1.30)% and(7.17±0.35)%, respectively.The levels of reactive oxygen species(ROS)in HK-2 cells in 50 μg/ml and 100 μg/ml PNS groups were(845.7±17.79)and(353.3±26.1), respectively.With the increase of PNS dose, super oxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activities increased and malonic dialdehyde(MDA)production decreased in the 3 PNS groups, compared with the H 2O 2 group, the differences were statistically significant(all P<0.01). Conclusions:PNS can protect HK-2 cells against oxidative damage by enhancing the activity of intracellular antioxidant enzymes, the effect is enhanced with the increase of the dose.

Non-alcoholic fatty liver disease (NAFLD) has gradually become the most prevalent chronic liver disease in the world, but its pathogenesis has not been fully elucidated. Ferroptosis is a novel type of programmed cell death caused by iron-dependent lipid peroxidation. Heme oxygenase-1 is a recognized antioxidant enzyme and an important regulatory factor in ferroptosis that modulates ferroptosis through various pathways and, in turn, regulates NAFLD. This paper reviews the regulatory mechanism of heme oxygenase-1 on NAFLD in ferroptosis pathway, with a view to clarifying the occurrence and development mechanisms of NAFLD and providing new vision and targets for its prevention and treatment.