BACKGROUND:Hydrogels have become a research hotspot due to their unique advantages in the biomedical field due to their superior mechanical and biological properties.At present,related research involves tissue engineering,wound dressing and so on. OBJECTIVE:To review the advantages and properties of hydrogels and the research progress of their application in the repair of oral and maxillofacial defects,discuss the current limitations and challenges of hydrogels in application and promotion,and provide new ideas for future research directions. METHODS:Relevant literature was searched in PubMed,CNKI,and WanFang database by computer.The search terms were"hydrogel,oral and maxillofacial defects,mechanical properties,tissue engineering,wound dressing"in Chinese and"hydrogel,oral and maxillofacial defects,mechanical properties,guided tissue regeneration,wound dressing"in English.Preliminary screening was carried out by reading titles and abstracts,and articles not related to the topic of the article were excluded.According to the inclusion and exclusion criteria,108 articles were finally included for the result analysis. RESULTS AND CONCLUSION:(1)The hydrogel has good biological activity,mechanical controllability,and stimulation response.(2)Polymer,metal,and ceramic hydrogel composites have appropriate mechanical properties,biodegradability,and controlled release rate,which are suitable for maxillofacial bone tissue engineering.(3)Fibrin-based hydrogel could fill the hollow nerve conduit through the nerve defect area and promote the regeneration and growth of axons to restore the function of maxillofacial nerve.(4)Controlling the interaction between nanomaterials and hydrogels can improve the formation of muscle fiber oriented structure to promote maxillofacial muscle tissue regeneration.(5)Polysaccharide hydrogel has gradually become the first choice for repairing irregular periodontal defects due to its ability to control drug delivery,carry bioactive molecules,and combine with other materials to produce the best scaffold matching the extracellular matrix.(6)Calcium phosphate or calcium carbonate-based hydrogels can be used to fill irregular or fine tissue defects and remineralize hard tissues.The self-assembled hydrogels are simple to prepare and have good biological activity.(7)Salivary gland-derived extracellular matrix-like gel is expected to participate in the treatment of many salivary gland diseases.(8)Hydrogels can be used as wound dressings in combination with biological adhesives,acellular biomaterials,antimicrobials,antioxidants,or stem cells to treat various wounds.(9)Fibrin-based hydrogel has the most potential in the repair of oral and maxillofacial defects.It has excellent biocompatibility,flexibility,and plasticity.It can combine with cells,extracellular matrix proteins,and various growth factors,and promote the osteogenic differentiation of mesenchymal stem cells,axon regeneration and growth,angiogenesis,myotube differentiation,salivary gland tissue regeneration,and periodontal tissue regeneration.It has a broad prospect in the repair of oral and maxillofacial defects.However,its therapeutic effect depends on the function of the substance carried.The complex preparation process,its safety and long-term efficacy,and the special anatomical oral and maxillofacial structure is the problem that hinders its promotion,which also provides directions for future research.

BACKGROUND:Graphene is the thinnest,strongest,and toughest type of two-dimensional new crystal material,demonstrating significant advantages in biomedical applications.Angiogenesis and vascularization of bone are key factors in tissue repair and regeneration,and are effective ways to address vascular and osteogenic issues. OBJECTIVE:To review the characteristics and mechanisms of graphene and its derivatives in promoting angiogenesis activity and vascularizing bone,in order to provide a reference for their clinical application in vascular tissue repair and regeneration. METHODS:Using a computer to search for relevant literature included in PubMed,ScienceDirect,CNKI,and Wanfang databases,the Chinese search terms were"grapheme","angiogenesis,vascularization","vascularized bone",and"endothelial cells",while the English search terms were"graphene""angiogenesis OR vascularization""vascularized bone""endothelial cells".After excluding literature unrelated to the topic of the article,according to the inclusion and exclusion criteria,62 articles were ultimately included for result analysis. RESULTS AND CONCLUSION:(1)At present,graphene oxide has been studied more and is the most widely used in graphene and its derivatives.(2)Graphene and its derivatives are suitable for heart,bone,nerve,and wound healing related diseases.(3)Graphene and its derivatives have excellent physical and chemical properties and biological properties,but they have potential cytotoxicity.We should pay attention to its biological safety in application.(4)The application of graphene and its derivatives requires further research to demonstrate the optimal size and concentration and measures to reduce toxicity.(5)On the cellular level,graphene and its derivatives can promote angiogenic activity by tip endothelial cell phenotype,mesenchymal stem cell adhesion and proliferation, and vascular smooth muscle cell growth.(6)On the molecular level,graphene and its derivatives can increase the expression of vascular endothelial growth factor,basic fibroblast growth factor,hepatocyte growth factor and activate reactive oxygen species/nitric oxide synthase/nitric oxide signaling pathway,lysophosphatilate R6/Hippo-YAP pathway,stromal cell-derived factor-1/vascular endothelial growth factor and ZEB 1/Notch1 pathway.(7)Grapheme oxide and graphene oxide-copper phosphorylated extracellular regulatory protein kinase and activated hypoxia-inducible factor-1,thereby promoting the up-regulation of vascular endothelial growth factor and bone morphogenetic protein-2 expression,and promoting angiogenesis and vascularized bone.(8)In summary,graphene and its derivatives,especially graphene oxide,have great application prospects in the repair and regeneration of vascularized tissues due to their excellent biological properties,good angiogenesis and vascularized bone ability.

Objective To establish an animal model of postmortem redistribution of amantadine,and to study its postmortem redistribution in rats,so as to provide experimental evidence for forensic identification.Methods One hundred and twenty-six male SD rats were randomly divided into 3 groups and subjected to intragastric administration according to the maximum dose of treatment(L),LD50(M)and 2LD50(H).Those who did not die were killed according to the average time of death of LD50.Heart-blood,peripheral blood,heart,liver,spleen,lung,kidney,brain,muscle and testis were collected at 0 h,6 h,12 h,24 h,48 h,72 h and 96 h after death,and amantadine content was detected.Results For the rats in the L group,the concentration of amantadine decreased within 6 h after death and then increased in the heart-blood,heart and liver,unchanged within 48 h and reached the peak at 96 h in the spleen,kidney,brain,muscle and testis,while decreased in the lung.For the rats in the M group,the concentration of amantadine decreased within 24 h after death and then increased in all samples,and it reached the peak at 48 h after death in the peripheral blood,spleen,kidney and muscle tissues,at 72 h after death in the heart-blood and testis,and at 96 h after death in the liver,lung and brain tissues.For the rats in the H group,the concentration of amantadine showed a downward trend within 12 h after death in the heart and liver tissue,showed a downward trend within 48 h after death in the lung,brain and muscle tissue,and reached the peak at 96 h after death in the heart,liver,spleen,muscle and testicle tissues.Conclusion The postmortem redistribution was found in amantadine poisoning dead rats,which could provide experimental evidence for the forensic identification of death cases caused by amantadine poisoning.

Objective:To analyze the correlation between the body composition and cardiorespiratory fitness (CRF) decline in physical examination population of different genders.Methods:Clinical data of the cardiopulmonary exercise testing (CPET) and body composition analysis of 439 people who received physical examination in the Medical Examination Center of Peking University Third Hospital from May 2021 to September 2021 were retrospectively analyzed. The general data, physical examination, biochemical parameters, body composition and CPET results were collected. The subjects were divided into normal group and decline group according to the percentage of peak oxygen uptake (VO 2peak) levels ≥ 85% or<85%. Multivariate logistic regression was applied to investigate the influencing factors of CRF decline in subjects of different genders. Results:Among men, total cholesterol and triglyceride in the decline group were significantly higher than those in the normal group [(5.097±0.890) vs (4.865±0.856) mmol/L, (1.778±1.200) vs (1.485±0.709) mmol/L], and the blood homocysteine (Hcy) and skeletal muscle index were significantly lower than those in the normal group [13.00 (11.30, 15.90) vs 13.80 (12.05, 17.10) μmol/L, (7.89±0.65) vs (8.08±0.64) kg/m 2] (all P<0.05). Among women, skeletal muscle index in the decline group was significantly lower than that in the normal group [(6.21±0.52) vs (6.53±0.56)kg/m 2], and percent body fat was significantly higher than that in the normal group [(32.83±4.92)% vs (31.21±4.55)%] (all P<0.05). The elevation of triglyceride level ( OR=1.487, 95% CI: 1.042-2.121) and visceral fat area ( OR=1.032, 95% CI: 1.014-1.051) were positively correlated with the decline of CRF in man, the decrease of skeletal muscle index ( OR=0.215, 95% CI: 0.106-0.435) and the increase of percent body fat ( OR=1.149, 95% CI: 1.060-1.245) were positively correlated with the decrease of CRF in women (all P<0.05). Conclusions:There is a correlation between body composition and CRF decline in physical examination population of different genders. Men should control visceral fat more effectively, and women should pay attention to increase muscle mass while reducing body fat, in order to improve CRF.

Objective:To investigate the associations between serum uric acid levels during the third trimester of pregnancy and risks of adverse pregnancy outcomes.Methods:In this retrospective study, a cohort of 7 995 pregnant women who were hospitalized for childbirth from January 2014 to January 2019 were collected to compare pregnancy outcomes between subjects with or without hyperuricemia (HUA). A smooth curve analysis was used to evaluate the relationship between uric acid levels and preterm delivery, low birth weight and smaller than gestational age. Logistic regression analyses were performed to identify risk factors for adverse pregnancy outcomes, and the interaction of the factors.Results:During the third trimester of pregnancy, the uric acid levels of about 10% pregnant women were over 420 μmol/L. In those with HUA, the median neonatal birth weight was 2 590 (1 790, 3 410) g, the probability of premature birth was 49.81%, and the incidence of small than gestational age was 20.41%. These were significantly different from the women without HUA (the median neonatal birth weight: 3300 (2850, 3640) g; the probability of premature birth 23.09%; the incidence of small than gestational age 6.55%, respectively) (All P<0.001). Maternal uric acid levels were negatively correlated with neonatal birth weight, and positively correlated with the risk of smaller than gestational age. It has a U-shaped association with the probability of premature birth, and the lowest probability of premature birth was at 200-400 μmol/L of the uric acid. Risks of low birth weight (adjusted β=-5.22, 95% CI-6.46—-3.99) and smaller than gestational age (adjusted OR=1.03, 95% CI 1.02-1.04) were increased in the function of uric acid levels. High uric acid, hypertension, oligoamnios and preeclampsia were important risk factors for the adverse pregnancy outcomes. The risk of preterm delivery and low birth weight enhanced when hyperuricemia combined with hypertension and preeclampsia. Conclusions:Serum uric acid level can be used as one of reliable markers for predicting adverse pregnancy outcomes, which might provide theoretical basis for clinical intervention in practice.

Objective:To explore the relationship between frailty and nutritional status of the elderly in communities.Method:Using the convenience sampling method, 458 elderly people in the community were investigated with the general data questionnaire, frailty phenotype, Mini-Nutritional Assessment, Mini-Mental State Examination, Self-Rating Depression Scale and Instrumental Activity of Daily Living.Results:The prevalence of frailty, pre-frailty and non-frailty in the elderly of the community was 9.2%, 60.0%, and 30.8% respectively, and 10.5% were malnourished or at risk of malnutrition. Logistic analysis showed that malnutrition increased the risk of frailty in the elderly ( OR=9.534, P=0.001). Conclusion:Malnutrition is a risk factor of frailty in the elderly in communities. Improving the nutritional status of the elderly in communities can help delay the development of frailty.

Objective:To summarize and review a Chinese family with cerebrotendinous xanthomatosis (CTX) so as to improve understanding of the disease.Methods:The proband was admitted to the Department of Neurology， the Second Hospital of Hebei Medical University on May 30, 2019. The medical history, neuro-imaging, pathology, CYP27A1 gene of the proband and CYP27A1 gene of her family were analyzed. Clinical features of similar cases from published literatures were retrieved and systematically summarized.Results:The proband was a 39-year-old female who was admitted to the Second Hospital of Hebei Medical University due to weakness of both lower limbs lasted for more than five years and aggravated for one year with speech slurred. The proband manifested with mental retardation, bilateral pyramidal tract impairment and cerebellar lesions, and had cholesterol crystal in xanthomas and compound heterozygous mutations of c.435G>A and c.1263+1G>A in CYP27A1 gene. The proband′s sister had the same mutation as the proband′s. The proband′s mother was the carrier of c.435G>A mutation, and father was the carrier of c.1263+1G>A mutation. Seventeen related cases concerning CTX with detailed clinical data were searched with major domestic databases. Combined with this case, clinical features with the frequency more than 50% were pyramidal sign, mental decline, ataxia, dysarthria, achilles tendon neoplasm, cataract, high arch foot.Conclusions:The onset of CTX is hidden, which can be diagnosed by its pathology and CYP27A1 gene detection. The possibility of CTX should be considered when there are unexplained clinical manifestations in common diseases such as pyramidal sign, mental decline, ataxia, dysarthria, achilles tendon neoplasm, cataract, high arch foot and so on.

Objective:To investigate the clinical application of cervix-uterine internal target volume (ITV) in volume-modulated arc therapy (VMAT) for cervical cancer under different bladder filling conditions, aiming to obtain more accurate planning target volume (PTV).Methods:Sixty-two patients with cervical cancer receiving radiotherapy rather than surgery were selected and randomly divided into the study ( n=31) and control groups ( n=31). In the study group, individualized ITV, PTV and PTV margin were obtained under three bladder filling status by localization CT scan to compare the VMAT. The target area and organs at risk (OARs) within the target area were statistically compared between two groups. The target missing rate in CBCT, adverse events and short-term efficacy of radiotherapy were analyzed in two groups. Results:There was no significant difference in the volume of target area and OARs in the target area between two groups (both P>0.05). In the study group, the target missing rate and target missing volume were significantly lower compared with those in the control group (both P<0.05). There was no significant difference in the incidence of acute radiation-induced adverse events between two groups ( P>0.05). The 1-, 2-year overall survival and progress-free survival did not significantly differ between two groups (all P>0.05). One patient in the study group had uterine recurrence and 2 cases in the control group. Conclusion:Application of individualized cervix-uterine ITV and PTV in definitive VMAT under different bladder filling conditions can improve the accuracy of target area contouring and improve the local control rate in cervical cancer patients.

Objective To externally validate the accuracy of combined use of neutrophil-lymphocyte ratio (NLR),V20,and Dmean in predicting the incidence of grade Ⅲ or higher radiation-induced lung injury (RILI) in lung cancer patients.Methods A total of 166 lung cancer patients,who participated in the model establishment were selected into the internal validation group,and 85 lung cancer patients who received intensity-modulated radiotherapy in our department between June 2016 and June 2018 were assigned into the external validation group.The incidence rate of grade 3 or higher RILI was statistically compared between the internal and external validation groups.Multivariate logistic analysis was performed for NLR,V20 and Dmean The discrimination degree of the predictive model was evaluated by using ROC curve in combination with NLR,V20 and Dmean The calibration degree of the predictive model was assessed by Hosmer-Lemeshow test.Results The incidence rate of grade 3 or higher RILI in the internal and external validation groups was 23.8％ and 22.9％.Multivariate logistic analysis demonstrated that NLR,V20 and Dmean significantly differed in the internal validation group (P=0.032,0.006 and 0.005).However,only V20 significantly differed in the external validation group (P=0.038).The discrimination and calibration degree of RILI was almost consistent between the internal and external validation groups (both P＞0.05).The area under the curve (AUC) predicted by NLR,V20,Dmean and the combination of three indexes were 0.611,0.646,0.682 and 0.775 in the internal validation group,and 0.544,0.702,0.658 and 0.754 in the external validation group,respectively.The calibration degree in the internal validation group was P=2.797and 0.834,P=2.452 and 0.653 in the external validation group.Conclusion Combined application of NLR,V20 and Dmean can accurately predict the incidence of grade Ⅲ or higher RILI in lung can cancer patients,which has been validated by external dataset.

Objective Compared with chest CT,endoscopic ultrasonography (EUS) can more accurately determine the upper and lower margins of esophageal cancer,and marking the upper and lower margins of the esophageal cancer with titanium clip contributes to the delineation of target area of esophageal cancer during radiotherapy.To compare the effects of esophageal X-ray,chest computed tomography (CT)scan and EUS-assisted placement of marker clip in the determination of the length of gross target volume (GTV),aiming to provide reference for the determination of GTV during esophageal cancer radiotherapy.Methods Thirty patients who were initially diagnosed with thoracic esophageal cancer by histological and cytological examinations and scheduled to receive radiotherapy were recruited in this investigation.All patients received esophageal X-ray,CT scan,and EUS-assisted placement of marker clip.The length of GTV was quantitatively measured and statistically compared among three different methods.Results The length of GTV was (6.1 ± 1.4) cm,(6.8± 1.9) cm and (6.3± 1.9) cm determined by esophageal X-ray,CT scan and EUS-assisted placement of marker clip,respectively.Compared with CT scan,the length of GTV determined by EUS-assisted placement of marker clip did not significantly differ (P=0.11).The length of GTV determined by esophageal X-ray was significantly shorter than that by CT scan (P =0.03).Among all patients,the length of GTV determined by EUS-assisted placement of marker clip was longer compared with that by chest CT scan in 22.2％ of patients.The length of GTV determined by EUS-assisted placement of marker clip was the same as that by chest CT scan in 11.1％ of patients.The length of GTV determined by EUS-assisted placement of marker clip was shorter compared with that by chest CT scan in 66.7％ of patients.Conclusions EUS-assisted placement of marker clip differs from esophageal X-ray and CT scan in determining the length of GTV,which acts as one of the effective methods in the determination of the length of GTV during esophageal cancer radiotherapy.