Assessing oral and toothbrush microbial profiles among high-altitude individuals with and without periodontal disease: a case-control study.

BACKGROUND: Periodontitis is the sixth-most common disease worldwide. The oral microbiome composition and its association with Periodontal disease (PD) have been largely explored; however, limited studies have explored the microbial profiles of both oral and toothbrushes in patients with PD. Thus, this study aimed to ascertain the oral and toothbrushes microbial composition in high-altitude populations, hypothesizing that their correlation with periodontal health would differ from those at lower altitudes, potentially indicating links between environmental factors, microbial colonization patterns, and periodontal health in distinct geographic contexts. METHODS: In the present study, we enrolled 35 individuals including 21 healthy and 14 diagnosed with PD from the Lhasa region of Tibet, China. Saliva and toothbrush samples were collected from each participant to assess the association between toothbrush usage and oral microbiome with PD using 16 S rRNA gene-specific V3-V4 regions sequencing. To assess the oral and toothbrush microbiome composition and diversity and its possible link to PD. RESULTS: Significantly higher Alpha diversity (Shannon index) was observed between the PD group and PD toothbrushes (p = 0.00021) and between the PD group and Healthy toothbrushes (p = 0.00041). The predominant species were Proteobacteria, Bacteroidota, Firmicutes, Actinobacteria, and Fusobacteria, with genera Pseudomonas, Veillonella, Neisseria, Acinetobacter, and Haemophilus. In addition, PICRUST2 analysis unveiled 44 significant pathways differentiating the disease and healthy groups, along with 29 pathways showing significant differences between their respective toothbrush microbial profiles. The distinct oral and toothbrush microbial composition among high-altitude populations suggests potential adaptations to the challenges of high-altitude environments. CONCLUSION: This study emphasizes the importance of tailored dental care strategies, accounting for altitude and racial factors, to effectively manage periodontal health in these communities. Further research is warranted to investigate the specific microbial mechanisms and develop targeted interventions for optimizing oral health in populations across varying altitudes.

Effect of Leaflet Pattering on Mechanical Valve Hydrodynamic Properties / 医学研究杂志

Objective To investigate the effects patterned structure located on the surface of mechanical valve leaflet exerted on the hydrodynamic properties of valve prostheses.Methods Bileaflet aortic mechanical valves of GKS 21A and 23 A were randomly selected as the control group,hydrodynamic performance of each valve were assessed,as per ISO5840 by calculating mean transvalvular pressure(MTP),regurgitation fraction(REG),effective orifice area(EOA)and effective orifice area(eLoss).Then,laser etching was applied to construct a parallel-groove array pattern on leaflet surface perpendicular to the direction of the blood flow.The valve was subjected a-gain to the same test,and the data obtained were recorded and analyzed.Results In the pulsating flow test,the MTP of the experimental group was smaller than that of the control group at the same flow rate and size.The RE in GKS 21A experimental group was smaller than that in control group,and the RE in GKS 23A experimental group was larger than that in control group.The EOA in the experimental group was larger than that in the control group at the same flow rate and size.The eLoss in the GKS 21A experimental group was smaller than that in the control group,and the eLoss in the GKS 23A experimental group was larger than that in the control group.Conclusion The parallel-groove array pattern on the surface of the leaflet affected the hemodynamic performance of the valve prostheses.

Hyaluronic acid hydrogel-encapsulated bone marrow mesenchymal stem cells promote cardiac function in myocardial infarction rats(Ⅲ) / 中国组织工程研究

BACKGROUND:Our previous experimental results have shown that hyaluronic acid hydrogel can act as a vehicle for bone marrow mesenchymal stem cell delivery to improve the cardiac function of rats with myocardial infarction. OBJECTIVE:To explore the molecular mechanism of bone marrow mesenchymal stem cells and hyaluronic acid hydrogel in promoting damaged heart repair. METHODS:Bone marrow mesenchymal stem cells from male Sprague-Dawley rats were isolated and cultured,and then hyaluronic acid-encapsulated bone marrow mesenchymal stem cells were cultured in vitro in a three-dimensional manner.A model of myocardial infarction was made by ligating the left anterior descending artery of female Sprague-Dawley rats.After 1 week,the model rats were screened by ultrasonic testing and then eligible ones were randomly divided into four groups:PBS group(n=12),hyaluronic acid group(n=12),bone marrow mesenchymal stem cell group(n=15),and hyaluronic acid-encapsulated bone marrow mesenchymal stem cell group(n=15).At 1 week after ligation,the model rats underwent the secondary thoracotomy followed by corresponding injections into the infarcted region and its marginal zone.The expression levels of matrix metalloproteinase-2,vascular endothelial growth factor,thymosin β4 and c-Kit were examined at post-injection day 1,week 1 and week 2 by western blot assay.At post-injection week 2,immunofluorescence staining was used to detect the differentiation of transplanted cells. RESULTS AND CONCLUSION:(1)The expression levels of matrix metalloproteinase-2 and vascular endothelial growth factor protein in the infarct zone in the bone marrow mesenchymal stem cell group were significantly up-regulated at week 1 compared with the other three groups(P<0.05).At week 2,the hyaluronic acid group had a lower expression of matrix metalloproteinase-2 and vascular endothelial growth factor protein than the other three groups(P<0.05).However,the expression of matrix metalloproteinase-2 and vascular endothelial growth factor protein in the hyaluronic acid+bone marrow mesenchymal stem cell group was not significantly different compared with the bone marrow mesenchymal stem cell group.This was primarily attributable to a prolonged paracrine effect via the controlled release of the hyaluronic acid hydrogel.This prolonged paracrine effect offsets the inhibitory effect induced by hyaluronic acid hydrogel at 2 weeks.(2)Compared with the PBS group,thymosin β4 and c-Kit expression levels in the hyaluronic acid group,bone marrow mesenchymal stem cell group and bone marrow mesenchymal stem cell+hyaluronic acid group were significantly increased(P<0.05).(3)No differentiation of transplanted cells into cardiomyocytes or blood vessels was detected 2 weeks after transplantation.(4)It is indicated that transplanted bone marrow mesenchymal stem cells promote myocardial repair through the paracrine effect,and hyaluronic acid hydrogel prolongs the paracrine effect of transplanted bone marrow mesenchymal stem cells.

Circulating microbiota and metabolites: Insights into cardiovascular diseases.

BACKGROUND: In almost every country, cardiovascular diseases are the major cause of death, which are responsible for 17.7 million deaths worldwide, or 54% of all deaths. However, the latest evidence has shown that non-communicable diseases such as obesity, diabetes, and cardiovascular events are significantly influenced by the blood microbiota and circulating metabolites. METHODS: We searched online databases for the most recent related papers through the comprehensive international databases of the Institute of PubMed/ MEDLINE, ISI/WOS, and Scopus up to August 2022, using MESH terms and the related keywords in the English language. Considering the titles and abstracts, unrelated studies were excluded. The full texts of the remained studies were evaluated by authors, independently. Then, the studies' findings were assessed and reported. RESULTS: The study demonstrated that the bacterial profiles of patients with cardiovascular diseases and healthy individuals are significantly different. The diseased patients showed a significantly high abundance of phylum Proteobacteria, an important Proteobacterial component known as lipopolysaccharides that has been linked to the pathogenesis of cardiovascular disease, while phylum Firmicutes were found in healthy individuals. It suggests that Proteobacteria has a direct role in the onset of cardiovascular disease. CONCLUSION: We focused on the blood bacterial composition and circulating microbial metabolites in their relationship with the etiology and onset of cardiovascular disease. However, the various genera and species in the results reported were not always identical. Therefore, the microbial community structure of blood was more complicated and thus required a more in-depth exploration.

Analysis of the blood bacterial composition of patients with acute coronary syndrome and chronic coronary syndrome.

Emerging evidence revealed that the blood microbiota plays a role in several non-communicable diseases, including cardiovascular disease. However, the role of circulating microbes in atherosclerosis remains understudied. To test this hypothesis, we performed this study to investigate the microbial profile in the blood of Chines atherosclerosis volunteers. A total of seventy Acute Coronary Syndrome patients, seventy Chronic Coronary Syndrome patients, and seventy healthy individuals were examined using high-throughput Illumina Novaseq targeting the V3-V4 regions of the 16S rRNA gene. The relationship between atherosclerosis and blood microbiome, clinical variables, and their functional pathways were also investigated. Our study observed significantly higher alpha diversity indices (Chao1, p = 0.001, and Shannon, p = 0.004) in the acute coronary syndrome group compared with chronic coronary syndrome and healthy group, although a significantly lower alpha diversity was observed in the chronic coronary syndrome compared to acute coronary syndrome and healthy group. Beta diversity based on principal coordinate analysis demonstrated a major separation among the three groups. In addition, using linear discriminant analysis, a significant distinct taxon such as Actinobacteria _ phylum, and Staphylococcus_ genus in the healthy group; Firmicutes_ phylum, and Lactobacillus_ genus in the chronic coronary syndrome group, and Proteobacteria and Acidobacteriota _ phyla in acute coronary syndrome group were observed among three groups. Clusters of Orthologous Genes grouped and Kyoto Encyclopedia of Genes and Genomes pathways suggested a significant variation among all groups (p < 0.05). The blood microbiota analysis provides potential biomarkers for the detection of coronary syndromes in this population.

Comparison of Microbial Populations in the Blood of Patients With Myocardial Infarction and Healthy Individuals.

Increased bacterial translocation in the gut and bloodstream infections are both major comorbidities of heart failure and myocardial infarction (MI). However, the alterations in the microbiome of the blood of patients with MI remain unclear. To test this hypothesis, we conducted this case-control study to explore the microbiota compositions in the blood of Chinese patients with MI. Using high-throughput Illumina HiSeq sequencing targeting the V3-V4 region of the 16S ribosomal RNA (rRNA) gene, the microbiota communities in the blood of 29 patients with MI and 29 healthy controls were examined. In addition, the relationship between the blood microbiome and clinical features of MI was investigated. This study revealed a significant reduction in alpha diversity (Shannon index) in the MI group compared with the healthy controls. Also, a significant difference was detected in the structure and richness between the patients with MI and healthy controls. The members of the phylum Actinobacteria, class Actinobacteria, order Bifdobacteriales, family Bifidobacteriaceae, and genus Bifidobacterium were significantly abundant in the MI group, while the members of the phylum Bacteroidetes, class Bacteroidia, and order Bacteroidales were significantly enriched in the healthy controls (p < 0.05). Moreover, the functional analysis revealed a significant variation between both groups. For instance, the enrichment of genes involved in the metabolism pathways of three amino acids decreased, that is, nucleotide transport and metabolism, coenzyme transport and metabolism, and lipid transport and metabolism, among others. Our study will contribute to a better knowledge of the microbiota of blood, which will further lead to improved MI diagnosis and therapy. Further study is needed to determine the role of the blood microbiota in human health and disease.

Exploring blood microbial communities and their influence on human cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD) is the single biggest contributor to global mortality. CVD encompasses multiple disorders, including atherosclerosis, hypertension, platelet hyperactivity, stroke, hyperlipidemia, and heart failure. In addition to traditional risk factors, the circulating microbiome or the blood microbiome has been analyzed recently in chronic inflammatory diseases, including CVD in humans. METHODS: For this review, all relevant original research studies were assessed by searching in electronic databases, including PubMed, Google Scholar, and Web of Science, by using relevant keywords. RESULTS: This review demonstrated that elevated markers of systemic bacterial exposure are associated with noncommunicable diseases, including CVD. Studies have shown that the bacterial DNA sequence found in healthy blood belongs mainly to the Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria phyla. In cardiac events, such as stroke, coronary heart disease, and myocardial infarction, the increased proportion of Proteobacteria and Actinobacteria phyla was found. Lipopolysaccharides are a major component of Proteobacteria, which play a key role in the onset of CVD. Moreover, recently, a study reported the lower cholesterol-degrading bacteria, including Caulobacterales order and Caulobacteraceae family were both considerably reduced in myocardial infarction. CONCLUSION: Proteobacteria and Actinobacteria were shown to be independent markers of the risk of CVD. This finding is evidence for the new concept of the role played by blood microbiota dysbiosis in CVD. However, the association between blood microbiota and CVD is still inconsistent. Thus, more deep investigations are required in future to fully understand the role of the bacteria community in causing and preventing CVD.

Flocked swab might be one main reason causing the high false-negative rate in COVID-19 screening----the advantages of a novel silicone swab

RNA testing using RT-PCR can provide direct evidence for diagnoses of COVID-19 which has brought unexpected disasters and changes to our human society. However, the absorption of cotton swab for RNA lysates may lead to a low concentration of detectable RNA, which might be one of the main reasons for the unstable positive detecting rate. We designed and manufactured a kind of silicone swab with concave-convex structure, and further compared the effects of silicone and cotton swab on RNA extraction. Principal component analysis and Paired Wilcoxcon test suggested that a higher RNA concentration and A260/A280 would be obtained using silicone swab. The results indicated that our silicone swab had a more excellent ability to sample than the cotton swab, characterized by the higher quantity and quality of extracted RNA. Thus, we advised that the current cotton swabs need to be improved urgently in COVID-19 diagnoses and the process of "sample collection" and "sample pre-processing" must be standardized and emphasized. HighlightsThe current cotton swabs need to be improved urgently in COVID-19 screening.

Design of an axial blood pump of diffuser with splitter blades and cantilevered main blades / 生物医学工程学杂志

An implantable axial blood pump was designed according to the circulation assist requirement of severe heart failure patients of China. The design point was chosen at 3 L/min flow rate with 100 mm Hg pressure rise when the blood pump can provide flow rates of 2-7 L/min. The blood pump with good hemolytic and anti-thrombogenic property at widely operating range was designed by developing a structure that including the spindly rotor impeller structure and the diffuser with splitter blades and cantilevered main blades. Numerical simulation and particle image velocimetry (PIV) experiment were conducted to analyze the hydraulic, flow fields and hemolytic performance of the blood pump. The results showed that the blood pump could provide flow rates of 2-7 L/min with pressure rise of 60.0-151.3 mm Hg when the blood pump rotating from 7 000 to 11 000 r/min. After adding the splitter blades, the separation flow at the suction surface of the diffuser has been reduced efficiently. The cantilever structure changed the blade gap from shroud to hub that reduced the tangential velocity from 6.2 m/s to 4.3-1.1 m/s in blade gap. Moreover, the maximum scalar shear stress of the blood pump was 897.3 Pa, and the averaged scalar shear stress was 37.7 Pa. The hemolysis index of the blood pump was 0.168% calculated with Heuser's hemolysis model. The PIV and simulated results showed the overall agreement of flow field distribution in diffuser region. The blood damage caused by higher shear stress would be reduced by adopting the spindle rotor impeller and diffuser with splitter blades and cantilevered main blades. The blood could flow smoothly through the axial blood pump with satisfactory hydraulics performance and without separation flow.

[Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans].

OBJECTIVE: This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans). METHODS: In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions. RESULTS: 1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 µmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05). CONCLUSION: C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.

Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans).</p><p><b>METHODS</b>In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions.</p><p><b>RESULTS</b>1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 μmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05).</p><p><b>CONCLUSION</b>C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.</p>

Numerical simulation of LVAD inflow cannulas with different tips / 生物医学工程学杂志

The tip structure is one of the key factors to determine the performance of left ventricular assist device (LVAD) inflow cannulas. The tip structure influences the thrombosis, hemolysis in cannula and left ventricle and suction leading to obstruction in ventricle. We designed four kinds of inflow cannulas that had different tips and built the numerical models of the four historical used inflow cannulas inserted into the apex of left ventricle. We computed the hemodynamic characteristics of inflow cannulas insertion by Fluent software. We researched the backflow, turbulent flow and pressure distribution of the four inflow cannulas. The results showed that the trumpet tipped inflow cannula had smooth flow velocity distribution without backflow or low velocity flow. The trumpet tipped inflow cannula had the best blood compatibility characteristics. The trumpet structure could prevent obstruction. The caged tipped cannula had serious turbulent flow which could possibly cause thrombosis and the low pressure near left ventricle wall and easily lead to ventricle collapse. The trumpet tipped inflow cannula has the best blood compatibility and is difficult to be obstructed. The trumpet tipped inflow cannula is fit to long-term use LVAD.

Oral health status and its correlation with oral health knowledge among middle-aged people in Dongxiang, Bonan, and Yugur / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To provide basic data for the prevention of oral diseases in minorities by investigating the oral health status and behavior related to oral health knowledge of individuals aged 35 to 44 years in Dongxiang, Bonan, and Yugur.</p><p><b>METHODS</b>The caries and periodontal health of 445 individuals aged 35 to 44 years were examined according to the method and criterion prescribed by the World Health Organization and the Third National Oral Health Epidemiologic Investigation. A questionnaire survey on related oral health knowledge and behavior was conducted.</p><p><b>RESULTS</b>The crown caries prevalence rate in Dongxiang, Baoan, and Yugur were 48.28%, 79.47%, and 67.11%, respectively; the root caries prevalence rates were 38.62%, 69.54%, and 42.95%, respectively. The rates of gum bleeding in Dongxiang, Bonan, and Yugur were 86.90%, 90.07%, and 65.77%, respectively. The rates of dental calculus in Dongxiang, Bonan, and Yugur were 99.31%, 100.00%, 99.33%, respectively, and the rates of periodontal bags were 68.97%, 67.55%, and 43.62%, respectively. Only 69.84% of the respondents brush their teeth every day; 94.90% of the respondents do not floss. Only 20.19% of the respondents contact a doctor for a toothache, and 42.23% of the respondents have never seen a dentist.</p><p><b>CONCLUSION</b>Caries morbidity is high among the respondents aged 35 to 44 years from Dongxiang, Bonan, and Yugur. The periodontal health status and oral hygiene of the respondents are poor, and behavior related to oral health knowledge is insufficient. Thus, more attention must be provided to the prevention and control of caries and periodontal diseases among middle-aged people in the area.</p>

Comparison of CM-DIL and DAPI labeled bone marrow-derived mesenchymal stem cells / 中国组织工程研究

BACKGROUND:cellmarker technology has been widely applied in many studies concerning celltransplantation. Chlormethylbenzamido-1,1-dioctadecyl-3,3,3’3’-tetramethylin-docarbocyamine (CM-DIL) and 4’,6-diamidino-2-phenylindole (DAPI) are commonly used for labeling cells. To our knowledge, there are few reports on comparing the two fluorescent dyes. OBJECTIVE:To compare the effects of CM-DIL and DAPI on labeling bone marrow mesenchymal stem cells in vitro and in vivo. METHODS:Isolation and expansion of bone marrow-derived mesenchymal stem cells were performed according to attachment culture. The cells were labeled by CM-DIL and DAPI, respectively. cellviability was assessed via trypan blue exclusion assay. Growth curves of bone marrow-derived mesenchymal stem cells were depicted using MTS assay. The reduction of fluorescent intensity was observed under an inverted fluorescent contrast phase microscope from passage 1 to passage 3 after labeling. Myocardial infarction was induced by left anterior artery ligation in Sprague-Dawley rats. One week later, bone marrow-derived mesenchymal stem cells labeled by CM-DIL or DAPI were injected randomly into the border area of infarct myocardium. After 3 days, transplanted celldistribution was examined under the fluorescent microscope through paraffin sections and frozen sections respectively. RESULTS AND CONCLUSION:In vitro, bone marrow-derived mesenchymal stem cells labeled by both CM-DIL and DAPI showed decreased cellproliferation during the early period;the percentage of fluorescent-positive cells was approximately 100%in the two groups;however, the fluorescent intensity was significantly reduced from passage 1 to passage 3 in bone marrow-derived mesenchymal stem cells labeled by DAPI. In vivo, the transplanted cells were detected in a concentrated way both on the paraffin sections and frozen ones;the background color of frozen sections was lower in the CM-DIL group than in the DAPI group;false positive results of fluorescent expression could be eliminated in the CM-DIL group by using fluorescent mounting medium with the fluorescence of DNA staining. These data indicates that CM-DIL is more appropriate to in vivo tracing cells than DAPI.

Short term in vivo thrombosis evaluation of FW-Ⅱ axial blood pump for left ventricular assist / 中华胸心血管外科杂志

ObjectiveTo evaluate in vivo antithrombosis property of optimized FW-Ⅱ axial blood pump and provides evidence for future clinical use.MethodsA left ventricle-pump-descending aorta bypass model was established in five healthy sheep (60-70 kg) and the circulation of these sheep was assisted by FW-Ⅱ axial blood pump for 2 weeks.In preoperative and postoperative day 1,2,3,7,10 and 14,blood was drawn from the jugular vein to examine platelet activation and leukocyte-platelet aggregation respectively quantified with Annexin V,CD41/61 and CD14-PE by flow cytometry assays.Immediately after termination of the experiment,FW-Ⅱ axial blood pumps were explanted and each part was inspected for thrombus formation.Macroscopic and histological examinations were checked on heart,brain,kidney and spleen,respectively for thrombosis.ResultsCompared with preoperative baseline,the number of platelet activation and leukocyte-platelet aggregation reached a peak at postoperative day 2,it retained a high level within 7 days,then gradually decreased,but was still higher than preoperative level at dayl4.According to rotating speed,the number of platelet activation and platelet-leukocyte aggregation were lowest at the speed of 8000 r/min Minus thrombus were found in the front and rear hub of the pump rotor,and there was no thrombus at other components (flow straighter,impeller and pump housing).There were no ischemia and infarction evidences in macroscopic and histological examination of the heart,brain,kidney and spleen.ConclusionFW-II axial blood pump can be used to assist left ventricular circulation for 2 weeks with a satisfactory antithrombosis property.The level of platelet activation and leukocyte-platelet aggregation can be reduced to a lowest level at an optimized pump rotating speed.

Experiment study of the acellular bovine pericardium treated by dye-mediated photooxidation used as engineering heart tissue / 中华胸心血管外科杂志

ObjectiveTo evaluate the feasibility of constructing tissue engineering cardiac patch with photooxidationfixed acellular bovine pericardium.MethodsFresh bovine pericardia were treated by dye-mediated photooxidation after decellularization.Some of them were seeded with bone marrow stromal cells(MSCs) isolated from male SD rats to construct cardiac patches.Myocardial infarction(MI) model was made in female SD rats by left anterior descending coronary ligation(LAD).One week later, the confirmed MI rats were divided into three groups randomly, group MI (n = 15)without any treatment; group P (n = 18) with photooxidated pericardia implantation ; group P + C (n = 18) with seeded pericardia implantation.A sham group (n = 10) was also performed with opening and closing chest twice only.The heart were explanted at 2 or 4 weeks after implantation, and examined histologically and immunohistochemically.The heart function was evaluated by echocardiography at 4 weeks before excising the rats.ResultsThere were no cells or cell debris remained in bovine pericardium tissue.The fiber structure became condensed after photooxidation.The seeded cells formed a continuous layer on the surface of the tissue.The pericardial degradation level and newly formed microvessel density were larger in group P + C than in group P after 2 [ (13.7 ±5.2)个/mm2 vs (7.1 ±3.1)个/mm2, P＜0.05]and4 [(22.6 ±4.9)个/mrn2 vs (14.1 ±5.3)个/mm2, P＜0.05]weeks.Four weeks after transplantation, cardiac echocardiography showed left ventricular ejection fraction(LVEF) was lower in group MI (44.8 ± 4.4) ％ and group P (48.4 ± 5.0) ％ compared with group P + C (49.3 ± 4.8) ％, left ventricular fractional shorterning(LVFS) was lower in group MI (18.0 ± 2.2) ％ and group P (19.8 ± 2.5) ％ compared with group P + C (20.4 ±2.5) ％, the difference between P + C and MI was significant.ConclusionTransplantation of the tissue engineered bovine pericardial patches with dye-mediated photooxidation can improve heart function in MI rats.This kind of patches demonstrates a promising prospect in the future.

In vitro evaluation of biodegradable cardiac tissue engineering polyurethane scaffold / 中国组织工程研究

BACKGROUND: In vitro construction of tissue engineered cardiac muscle becomes a hot spot in recent years, and the selection and design of scaffold is the key link. However, there is lack of ideal cardiac tissue engineering scaffold material. OBJECTIVE: To evaluate the novel biodegradable polyurethane in vitro, and to discuss the feasibility of polyurethane as cardiac tissue engineeru scaffold. METHODS: A new type polyurethane (PV-Lys) was synthesized using diphenylmethane-4,4'-diisocyanate as hard segment and lysine as expand chain. The tensile and suture strength were tested in vitro respectively, hydrolytic degradation was carded out in phosphate buffer saline of pH 7.4 at 37 ℃, and cytotoxicity was evaluated by MTT measurement and morphological observation. RESULTS AND CONCLUSION: The tensile strength of the polyurethane was up to (8.1±0.1) MPa, and the suture strength was (12.2+0.8) N. The average value of the mass loss of PV-Lys was (13.1+0.3)% at 8 weeks of in vitro hydrolytic degradation. MTT assay results showed that the cytotoxic grade of the novel PV-Lys was 0-1. Cell morphology observation showed that the L929 cells were spindle-shaped or tdangular with good stretch. This PV-Lys scaffold is with favorable mechanical property, cytocompatibility, biodegradable property, which meets the requirements of tissue engineering application.

Effect of proteins pre-coating on bone marrow mesenchymal cells retention and proliferation on decellular bovine pericardium / 生物医学工程学杂志

To observe the growth of rat bone marrow mesenchymal cells (BMMCs) on decellular bovine pericardia in vitro and to investigate the effect of proteins pre-coating on cells retention and proliferation, bovine pericardia were decellularized using trypsin, DNase and Triton X-100 respectively. Then three proteins (fibronetin (FN), gelatin, collagen I) were coated on the surfaces of the bovine pericardia separately. BMMCs were harvested from rat thighbone marrow , then expanded and seeded onto decellular bovine pericardia with the proteins pre-coated . Decelluar bovine pericardia without coating were used as controls. The retention and growth of BMMSCs were observed by Hochest staining and analyzed by MTT method. It was shown that the retention and proliferation of BMMCs on FN group and gelatin group were significantly enhanced comparing with those on collagen I group and control group (P < 0.001). There was no significant difference between FN group and gelatin group (P > 0.05), nor between collagen I group and control group (P > 0.05). We conclude that the retention and proliferation of seeding cells on FN and gelatin could be significantly improved on decellular bovine pericardia (DBP) but not on collagen I.

Biostability and calcification resistance of valved bovine jugular veins stabilized by dye-mediated photooxidation / 生物医学工程学杂志

This study was conducted to make an in vitro evaluation of the biological characteristic of valved bovine jugular veins stabilized by dye-mediated photooxidation. The fresh valved bovine jugular veins were stabilized by dye-mediated photooxidation. The glutaraldehyde-treated veins and fresh veins served as controls. The samples were subjected to protein extraction assay and pepsin digestion assay, and were analyzed by polyacrylamide gel electrophoresis. The rat subcutaneous model for assessment of tissue calcification and immunologic properties was used. Calcium levels were determined by elemental analysis on dried samples and von Kossa staining. Both photooxidized and glutaraldehyde-treated tissues were resistant to protein extraction and pepsin digestion, compared to fresh tissue. Calcification levels were much lower for photooxidized tissues when compared with those for both glutaraldehyde-treated and fresh tissues. The perigraft infiltrate was lower in the photooxidized tissues than in the fresh and glutaraldehyde-treated tissues. Valved bovine jugular veins stabilized by dye-mediated photooxidation were biostable and resistant to calcification, and the immunologic property was well.

Reconstruction of right ventricular outflow tract with bovine jugular vein valved conduit: a preliminary clinical report / 中华胸心血管外科杂志

Objective To summarize the experience in application of the bovine jugular vein valved conduct in right ventricular outflow tract (ROVT) reconstruction. Methods Totally 14 patients [6 male, (6.3?5.4) years old] underwent ROVT reconstruction from February 2004 to March 2005 was recorded, and the function of the implanted bovine jugular vein valved conduit was evaluated by Doppler echocardiography one month later after operation. Results There was no perioperative morbidity related to the bovine jugular vein valved conduit. 14 patients were discharged well. One month after operation, echocardiography showed that reconstructed ROVT was patent, and only four implanted conduits had mild regurgition. Conclusion The bovine jugular vein valved conduit provides the favorable hemodynamic performance and thus could be an excellent substitute for the homograft in the reconstruction of ROVT. The mid- and long-term outcomes required further study.