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1.
Surg Radiol Anat ; 46(5): 635-643, 2024 May.
Article in English | MEDLINE | ID: mdl-38517513

ABSTRACT

PURPOSE: Cone-beam computed tomography (CBCT) was used in this study for evaluating the diameter, prevalence, spatial location, and risk factors of the accessory canal (AC) of the canalis sinuosus. METHODS: A comprehensive assessment of the incidence rate, diameter, three-dimensional (3D) spatial location, and direction of travel of AC was performed on 1003 CBCT images. The CBCT data were used to reconstruct a 3D model of the maxilla to determine the alveolar bone volume. The obtained data were further analyzed and processed. RESULTS: AC was present in 50.1% of images. Male patients more frequently had ACs than female patients did (P < 0.01) and was positively correlated with the maxillary alveolar bone volume (P < 0.001, OR 1.532). Age or nasopalatine canal diameter were not significantly associated with the occurrence of AC (P > 0.05). Among the 502 patients with AC, AC was present on the left side, right side, and bilaterally in 189, 98, and 215, respectively. The maximum number of ACs observed per individual was eight. The average AC diameter was 0.89 ± 0.26 mm (minimum, 0.5 mm; maximum, 2.02 mm). CONCLUSIONS: As the prevalence of AC and its trajectory display considerable variation among individuals, surgeons must consider the possibility of the presence of AC when devising surgical plans involving the anterior maxillary region.


Subject(s)
Anatomic Variation , Cone-Beam Computed Tomography , Imaging, Three-Dimensional , Humans , Male , Female , Middle Aged , Adult , Risk Factors , Aged , Adolescent , Young Adult , Maxilla/diagnostic imaging , Maxilla/anatomy & histology , Aged, 80 and over , Child , Retrospective Studies
2.
Front Surg ; 9: 893404, 2022.
Article in English | MEDLINE | ID: mdl-35722530

ABSTRACT

Background: Percutaneous vertebroplasty (PVP), percutaneous kyphoplasty (PKP), and bone-filling mesh containers(BFC) are three viable minimally invasive techniques that have been used to treat Kümmell's disease(KD). However, there is still debate as to which is safer and more effective. This study summarized the pros and cons of the three techniques in the treatment of KD through network meta-analysis(NMA). Methods: All eligible published clinical control studies comparing PVP, PKP, and BFC for KD up to December 2021 were collected by online search of Cochrane Library, PubMed, Embase, CNKI, Wanfang Database, and Chinese biomedical literature database. Data were extracted after screening, and Stata 16.0 software was used to perform the network meta-analysis. Results: Four randomized controlled trials (RCTs) and 16 retrospective case-control studies (CCTs) with a total of 1114 patients were included. The NMA results showed no statistical difference between the 3 procedures in terms of improving patients' clinical symptoms. PKP was most likely to be the most effective in correcting kyphosis, while BFC was likely to be the most effective in managing the occurrence of cement leakage. No statistical differences were found in the incidence of new vertebral fractures in adjacent segments. Conclusions: Ranking analysis showed that BFC has the highest likelihood of being the optimal procedure for the treatment of KD, based on a combined assessment of effectiveness in improving patients' symptoms and safety in the occurrence of adverse events.

3.
J Orthop Translat ; 28: 47-54, 2021 May.
Article in English | MEDLINE | ID: mdl-33717981

ABSTRACT

BACKGROUND: Chondrons are composed of chondrocytes and the surrounding pericellular matrix (PCM) and function to enhance chondrocyte-mediated cartilage tissue engineering. This study aimed at investigating the potential effect of combined chondrocytes with chondrons on the production of proteoglycan and collagen-II (Col-2) and the repair of defective knee cartilage in rabbits. METHODS: Chondrocytes and chondrons were isolated from the knee cartilage of rabbits, and cultured alone or co-cultured for varying periods in vitro. Their morphology was characterized by histology. The levels of aggrecan (AGG), Col-2 and glycosaminoglycan (GAG) expression were quantified by qRT-PCR, Alcian blue-based precipitation and ELISA. The effect of combined chondrocytes with chondrons in alginate spheres on the repair of defective knee cartilage was examined in rabbits. RESULTS: The isolated chondrocytes and chondrons displayed unique morphology and began to proliferate on day 3 and 6 post culture, respectively, accompanied by completely degenerated PCM on day 6 post culture. Evidently, chondrocytes had stronger proliferation capacity than chondrons. Longitudinal analyses indicated that culture of chondrons, but not chondrocytes, increased AGG mRNA transcripts and GAG levels with time and Col-2 mRNA transcripts only on day 3 post culture. Compared with chondrocytes or chondrons alone, co-culture of chondrocytes and chondrons significantly up-regulated AGG and Col-2 expression and GAG production, particularly at a ratio of 1:1. Implantation with chondrocytes and chondrons at 1:1 significantly promoted the repair of defective knee cartilage in rabbits, accompanied by reduced the Wakiteni scores with time. CONCLUSION: Combined chondrons with chondrocytes promoted the production of extracellular matrix and the repair of defective knee cartilage in rabbits. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This study explores that the combination of chondrons and chondrocytes may be new therapeutic strategy for cartilage tissue engineering and repair of defective cartilage.

5.
J Gastroenterol Hepatol ; 36(1): 196-203, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32537806

ABSTRACT

BACKGROUND AND AIM: Tubulointerstitial nephritis antigen-like 1 (TINAGL1), as a novel matricellular protein, has been demonstrated to participate in cancer progression, whereas the potential function of TINAGL1 in gastric cancer (GC) remains unknown. METHODS: The expression pattern of TINAGL1 in GC was examined by immunohistochemistry, ELISA, real-time polymerase chain reaction, and Western blot. Correlation between TINAGL1 and matrix metalloproteinases (MMPs) was analyzed by the GEPIA website and Kaplan-Meier plots database. The lentivirus-based TINAGL1 knockdown, CCK-8, and transwell assays were used to test the function of TINAGL1 in vitro. The role of TINAGL1 was confirmed by subcutaneous xenograft, abdominal dissemination, and lung metastasis model. Microarray experiments, ELISA, real-time polymerase chain reaction, and Western blot were used to identify molecular mechanism. RESULTS: TINAGL1 was increased in GC tumor tissues and associated with poor patient survival. Moreover, TINAGL1 significantly promoted GC cell proliferation and migration in vitro as well as facilitated GC tumor growth and metastasis in vivo. TINAGL1 expression in GC cells was accompanied with increasing MMPs including MMP2, MMP9, MMP11, MMP14, and MMP16. GEPIA database revealed that these MMPs were correlated with TINAGL1 in GC tumors and that the most highly expressed MMP was MMP2. Mechanically, TINAGL1 regulated MMP2 through the JNK signaling pathway activation. CONCLUSIONS: Our data highlight that TINAGL1 promotes GC growth and metastasis and regulates MMP2 expression, indicating that TINAGL1 may serve as a therapeutic target for GC.


Subject(s)
Cell Proliferation/genetics , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/metabolism , Gene Expression Regulation, Neoplastic/genetics , Gene Expression/genetics , Lipocalins/genetics , Lipocalins/metabolism , Matrix Metalloproteinases/genetics , Matrix Metalloproteinases/metabolism , Neoplasm Metastasis/genetics , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Up-Regulation/genetics , Up-Regulation/physiology , Animals , Cell Line , Cell Movement/genetics , Disease Models, Animal , Disease Progression , Extracellular Matrix Proteins/physiology , Female , Humans , Lipocalins/physiology , Mice, Nude , Molecular Targeted Therapy , Stomach Neoplasms/therapy
6.
ACS Appl Mater Interfaces ; 12(24): 27001-27009, 2020 Jun 17.
Article in English | MEDLINE | ID: mdl-32459950

ABSTRACT

Bismuth telluride (Bi2Te3)-based thermoelectric materials are well-known for their high figure-of-merit (zT value) in the low-temperature region. Stable joints in the module are essential for creating a reliable device for long-term applications. This study used electroless Co-P to prevent a severe interfacial reaction between the joints of solder and Bi2Te3. A thick and brittle SnTe intermetallic compound layer was successfully inhibited. The strength of the joints improved, and the fracture mode became more ductile; furthermore, there was no significant degradation of thermoelectric properties after depositing the Co-P layer after long-term aging. The result suggests that electroless Co-P could enhance the interfacial stability of the joints and be an effective diffusion barrier for Bi2Te3 thermoelectric modules.

7.
Transl Cancer Res ; 9(12): 7432-7439, 2020 Dec.
Article in English | MEDLINE | ID: mdl-35117343

ABSTRACT

BACKGROUND: Glioblastoma (GB) is the most common and aggressive brain and central nervous system malignancy. MicroRNAs (miRNAs) have been demonstrated to be predictors of prognostic outcomes, playing an important role in the pathogenesis and progression of GB. We aim to identify the potential miRNAs in GB. METHODS: GSE103228 was downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed miRNAs (DE-miRNAs) using the Student's t-test. Potential target genes for DE-miRNAs were predicted using miRTarBase, and their functions were analyzed using Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The protein-protein interaction (PPI) network was constructed using the STRING database and visualized using Cytoscape to identify a hub target gene-miRNA network. Furthermore, the expression of GB target genes was verified using University of Alabama Cancer (UALCAN) database. RESULTS: A total of 49 DE-miRNAs were identified in GB including 30 down-regulated miRNAs and 19 up-regulated miRNAs. Our analysis predicted 1,118 and 1,063 potential target genes from the top three most up-regulated and down-regulated DE-miRNAs, respectively, that were enriched in several GB-related pathways including the cancer pathway. ACTB and MYC were considered to be hub genes in our PPI networks. CONCLUSIONS: MiR-218-5p and miR-148a-3p regulated most of the hub genes and miR-148a-3p appeared to be a prognostic biomarker.

8.
Acta Biomater ; 100: 52-60, 2019 12.
Article in English | MEDLINE | ID: mdl-31606530

ABSTRACT

Vascular stiffening is associated with the prognosis of cardiovascular disease (CVD). Endothelial dysfunction, as shown by reduced vasodilation and increased vasoconstriction, not only affects vascular tone, but also accelerates the progression of CVD. However, the precise effect of vascular stiffening on endothelial function and its mechanism is unclear and a possible underlying has not been determined. In this study, we found that increasing substrate stiffness promoted endothelin-1 (ET-1) expression and inhibited endothelial nitric oxide synthase expression in human umbilical vein endothelial cells. Additionally, miR-6740-5p was identified as a stiffness-sensitive microRNA, which was downregulated by a stiff substrate, resulting in increased ET-1 expression. Furthermore, we found that substrate stiffening reduced the expression and activity of the calcium channel TRPV4, which subsequently enhanced ET-1 expression by inhibiting miR-6740-5p. Finally, analysis of clinical plasma samples showed that plasma miR-6740-5p levels in patients with carotid atherosclerosis were significantly lower than those in healthy people. Taken together, our findings show a novel mechanically regulated TRPV4/miR-6740/ET-1 signaling axis by which substrate stiffness affects endothelial function. Our findings indicate that vascular stiffening induces endothelial dysfunction, thereby accelerating progression of CVD. Furthermore, this study indicates that endothelial dysfunction induced by improper biophysical cues from cardiovascular implants may be an important reason for complications arising from the use of cardiovascular implants. STATEMENT OF SIGNIFICANCE: Cardiovascular disease is the leading cause of morbidity and mortality worldwide. The incidence of cardiovascular disease is accompanied by increased vascular stiffness. Our work indicated that increased vascular stiffness accelerates the development of cardiovascular disease by inducing endothelial dysfunction, which is a key contributor to the pathogenesis of cardiovascular disease. In addition, we identified a novel underlying molecular pathophysiological mechanism by which increased stiffness induce endothelial dysfunction. Our work could help determine the pathogenesis of cardiovascular disease induced by biomechanical factors.


Subject(s)
Endothelin-1/metabolism , Extracellular Matrix/metabolism , Human Umbilical Vein Endothelial Cells/metabolism , Mechanotransduction, Cellular , MicroRNAs/metabolism , TRPV Cation Channels/metabolism , Calcium Signaling , Carotid Artery Diseases/blood , Carotid Artery Diseases/genetics , Case-Control Studies , Cell Adhesion , Cytoskeleton/metabolism , Cytosol/metabolism , Female , Gene Expression Regulation , HEK293 Cells , Humans , Male , MicroRNAs/blood , MicroRNAs/genetics , Middle Aged
9.
Nanomedicine (Lond) ; 14(19): 2519-2533, 2019 10.
Article in English | MEDLINE | ID: mdl-31317822

ABSTRACT

Aim: To explore the potential therapeutic effect of yttrium oxide nanoparticles (Y2O3 NPs) on fulminant hepatic failure. Materials & methods: RAW264.7 cells and a lipopolysaccharide/D-galactosamine-induced hepatic failure murine model were used to assess the effects of Y2O3 NPs. Results: Y2O3 NPs exhibited anti-inflammatory activity by scavenging cellular reactive oxygen species and dampening reactive oxygen species-mediated NF-κB activation in vitro. A single intraperitoneal administration of Y2O3 NPs (30 mg/kg) enhanced hepatic antioxidant status and reduced oxidative stress and inflammatory response in lipopolysaccharide/galactosamine-induced mice. Y2O3 NPs also attenuated hepatic NF-κB activation, cell apoptosis and liver injury. Conclusion: Y2O3 NP administration could be used as a novel therapeutic strategy for treating fulminant hepatic failure and oxidative stress-related diseases.


Subject(s)
Liver Failure, Acute/drug therapy , Nanoparticles/administration & dosage , Oxidative Stress/drug effects , Yttrium/pharmacology , Animals , Antioxidants/chemistry , Apoptosis/drug effects , Galactosamine/toxicity , Gene Expression Regulation/drug effects , Humans , Lipid Peroxidation , Lipopolysaccharides/toxicity , Liver/drug effects , Liver/pathology , Liver Failure, Acute/chemically induced , Liver Failure, Acute/pathology , Mice , NF-kappa B/genetics , Nanoparticles/chemistry , RAW 264.7 Cells , Reactive Oxygen Species/metabolism , Yttrium/chemistry
10.
J Trauma Acute Care Surg ; 85(2): 327-333, 2018 08.
Article in English | MEDLINE | ID: mdl-29787551

ABSTRACT

BACKGROUND: Platelets are essential for primary hemostasis and also play an important role in inflammatory reactions. The hemostatic property of cryopreserved platelets (CPPs) has been confirmed in the treatment of bleeding casualties, but inflammatory injury induced by CPP transfusion is relatively unclear. We aim to investigate the effects of CPP transfusion on inflammatory organ injury in mice after hemorrhage. METHODS: Mice were subjected to a volume-controlled hemorrhage over 1 hour, and then were transfused with fresh platelets (FPs), Liquid-stored platelets (LPPs), CPPs, or fresh frozen plasma (FFP, control). At 6 hours posttransfusion, mice were sacrificed, and blood and tissues were sampled. Tissue sections were examined histologically and by immunohistochemical staining of neutrophils and macrophages. Plasma alanine aminotransferase, hepatic myeloperoxidase activity and inflammatory cytokine levels were measured. RESULTS: Transfusion of stored platelets (LPPs and CPPs) caused more serious histological injury in liver and lung compared with FPs and FFP (p < 0.05). However, kidney histological injury was similar among groups. Significantly higher numbers of Ly-6G-positive neutrophils were detected in liver and of F4/80-positive macrophages in liver and lung of mice transfused with LPPs or CPPs compared with FPs or FFP (p < 0.05). Transfusion of CPPs caused the most severe inflammatory liver injury, as reflected by alanine aminotransferase levels, hepatic macrophage infiltration, and hepatic myeloperoxidase activity and inflammatory cytokine levels (macrophage inflammatory protein-2, tumor necrosis factor-α, and interleukin-1ß). CONCLUSION: Cryopreserved platelet transfusion is more likely to aggravate hemorrhage-induced liver and lung injury by activating macrophage and facilitating neutrophil infiltration into hepatic tissues.


Subject(s)
Cryopreservation , Hemorrhage/therapy , Multiple Organ Failure/etiology , Plasma , Platelet Transfusion/adverse effects , Alanine Transaminase/blood , Animals , Cytokines/blood , Disease Models, Animal , Hemorrhage/complications , Inflammation/pathology , Liver/physiopathology , Lung/physiopathology , Male , Mice , Mice, Inbred BALB C
11.
Shock ; 48(2): 196-200, 2017 08.
Article in English | MEDLINE | ID: mdl-28709157

ABSTRACT

OBJECTIVE: To compare the efficacy of hypotensive resuscitation with hypertonic saline dextran 70 (HSD) and lactated Ringer (LR) solutions in a rat model of hemorrhagic shock at a simulated altitude of 4,000 m. METHODS: Anesthetized rats were bled to maintain their mean arterial pressure (MAP) at 45 mm Hg for 1 h. The distal quarter of the tail was then amputated to allow free blood loss; rats were simultaneously resuscitated with 4 mL kg HSD (HSD group, n = 10) or 4 mL kg LR (LR group, n = 10), followed by hypotensive resuscitation with LR to maintain MAP at 55 to 60 mm Hg for 1 h. A control group received no resuscitation (n = 10). Afterward, the cut end of the tail was ligated. The MAP, acid-base balance, blood loss, volume of fluid infused, and survival were recorded. RESULTS: Compared with controls, HSD resuscitation improved MAP (without increasing uncontrolled blood loss), increased arterial pH and oxygen saturation (SaO2), decreased arterial lactate concentration at the end of resuscitation, and resulted in higher survival rate (P < 0.05). Hypotensive resuscitation with LR also maintained higher MAP, pH, and SaO2 than the control group, but was associated with increased blood loss and inferior survival (P > 0.05). CONCLUSIONS: For hemorrhagic shock at simulated high altitude, resuscitation of rats with a bolus of HSD was associated with reduced blood loss and serum lactate concentration, and superior SaO2, hemoglobin concentration and survival rate, compared with LR solution.


Subject(s)
Altitude , Dextrans/pharmacology , Hypotension/drug therapy , Resuscitation , Shock, Hemorrhagic/drug therapy , Sodium Chloride/pharmacology , Animals , Hypotension/physiopathology , Isotonic Solutions/pharmacology , Male , Rats , Rats, Sprague-Dawley , Ringer's Lactate , Shock, Hemorrhagic/physiopathology
12.
Mediators Inflamm ; 2016: 3549207, 2016.
Article in English | MEDLINE | ID: mdl-27746589

ABSTRACT

RBCs undergo numerous changes during storage and stored RBCs may induce adverse effects, ultimately resulting in organ injury in transfusion recipients. We tested the hypothesis that the addition of SP to stored RBCs would improve the quality of the stored RBCs and mitigate liver injury after transfusion in a murine model. RBCs were harvested from C57BL/6J mice and stored for 14 days in CPDA-1 containing either a solution of SP in saline or saline alone. Haemolysis, the 24-hour posttransfusion recovery, the oxygen-carrying capacity, and the SOD activity of stored RBCs were evaluated. The plasma biochemistry, hepatic MDA level, MPO activity, IL-6, TNF-α concentrations, and histopathology were measured two hours after the transfusion of stored RBCs. Compared with RBCs stored in CPDA-1 and saline, the addition of SP to stored RBCs restored their oxygen-carrying capacity and SOD activity, reduced the AST activity, BUN concentrations, and LDH activity in the plasma, and decreased the MDA level, MPO activity, and concentrations of IL-6 and TNF-α in the liver. These data indicate that the addition of SP to RBCs during storage has a beneficial effect on storage lesions in vitro and subsequently alleviates liver injury after the transfusion of stored RBCs in vivo.


Subject(s)
Blood Transfusion/methods , Erythrocytes/drug effects , Liver Diseases/therapy , Pyruvic Acid/pharmacology , Sodium/pharmacology , Animals , Blood Preservation , Disease Models, Animal , Hemoglobins/chemistry , Humans , Interleukin-6/blood , Lactic Acid/blood , Liver Diseases/pathology , Male , Malondialdehyde/blood , Mice , Mice, Inbred C57BL , Oxygen/chemistry , Peroxidase/blood , Superoxide Dismutase/blood , Superoxide Dismutase/metabolism , Time Factors , Tumor Necrosis Factor-alpha/blood
13.
Sci Total Environ ; 545-546: 465-75, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26760267

ABSTRACT

Canopy stomatal ozone (O3) flux (Fst,O3) in a plantation of Schima superba, an ecologically and economically important evergreen pioneer tree species in subtropical China, was quantified based on sap flow measurements during a 2-year period. Mean Fst,O3 and accumulated Fst,O3 (AFst0) were significantly higher in wet seasons from April to September (4.62 nmol m(-2) s(-1) and 35.37 mmol m(-2), respectively) than in dry seasons from October to March (3.90 nmol m(-2) s(-1) and 24.15 mmol m(-1), respectively), yet comparable between the 2 years of the experiment, being 4.23 nmol m(-2) s(-1) and 58.23 mmol m(-2) in April 2013-March 2014 and 4.29 nmol m(-2) s(-1) and 60.80 mmol m(-2) in April 2014-March 2015, respectively. At the diurnal scale, Fst,O3 generally peaked in the early to middle afternoon hours (13:00-15:00), while the maximum stomatal conductance (Gst,O3) typically occurred in the middle to late morning hours (09:00-11:00). Monthly integrated AFst0 reached the maximum in July, although accumulated O3 exposure (SUM0) was highest in October. Seasonally or yearly, the accumulated O3 doses, either exposure-based or flux-based, notably exceeded the currently adopted critical thresholds for the protection of forest trees. These results, on the one hand, demonstrated the decoupling between the stomatal uptake of O3 and its environmental exposure level; on the other hand, indicated the potential O3 risk for S. superba in the experimental site. Therefore, the present study endorses the use of sap flow measurements as a feasible tool for estimating Fst,O3, and the transition from the exposure-based toward flux-based metrics for assessing O3 risk for forest trees. Further studies are urgently needed to relate stomatal O3 uptake doses with tree growth reductions for an improved understanding of O3 effects on trees under natural conditions.


Subject(s)
Air Pollutants/metabolism , Environmental Monitoring , Ozone/metabolism , Theaceae/metabolism , China , Plant Stomata/metabolism
14.
Int J Biometeorol ; 60(4): 545-56, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26307638

ABSTRACT

It is widely accepted that substantial nighttime sap flux (J s,n) or transpiration (E) occurs in most plants, but the physiological implications are poorly known. It has been hypothesized that J s,n or E serves to enhance nitrogen uptake or deliver oxygen; however, no clear evidence is currently available. In this study, sap flux (J s) in Eucalyptus grandis × urophylla with apparent stem photosynthesis was measured, including control trees which were covered by aluminum foil (approximately 1/3 of tree height) to block stem photosynthesis. We hypothesized that the nighttime water flux would be suppressed in trees with lower stem photosynthesis. The results showed that the green tissue degraded after 3 months, demonstrating a decrease in stem photosynthesis. The daytime J s decreased by 21.47%, while J s,n decreased by 12.03% in covered trees as compared to that of control, and the difference was statistically significant (P < 0.01). The linear quantile regression model showed that J s,n decreased for a given daytime transpiration water loss, indicating that J s,n was suppressed by lower stem photosynthesis in covered trees. Predawn (ψ pd) of covered trees was marginally higher than that of control while lower at predawn stomatal conductance (g s), indicating a suppressed water flux in covered trees. There was no difference in leaf carbon content and δ(13)C between the two groups, while leaf nitrogen content and δ(15)N were significantly higher in covered trees than that of the control (P < 0.05), indicating that J s,n was not used for nitrogen uptake. These results suggest that J s,n may act as an oxygen pathway since green tissue has a higher respiration or oxygen demand than non-green tissue. Thus, this study demonstrated the physiological implications of J s,n and the possible benefits of nighttime water use or E by the tree.


Subject(s)
Eucalyptus/physiology , Plant Stems/physiology , Carbon/metabolism , Eucalyptus/anatomy & histology , Humidity , Nitrogen/metabolism , Periodicity , Photosynthesis/physiology , Plant Leaves/physiology , Plant Stems/anatomy & histology , Plant Transpiration , Temperature , Water/metabolism
15.
Ying Yong Sheng Tai Xue Bao ; 26(9): 2623-31, 2015 Sep.
Article in Chinese | MEDLINE | ID: mdl-26785542

ABSTRACT

In plantations of three different re-vegetation tree species (Schima superba, Acacia auriculaeformis and Eucalyptus citriodora) in southern China, the stem sap flow of individuals at different DBH classes were monitored using Granier's thermal dissipation probes. With synchronously-measured meteorological data, the canopy stomatal conductance (g(c)) was determined and the responses of g(c) to environmental variables were analyzed. We found that daytime mean g(c) in S. superba forest on average was significantly higher than those of A. auriculaeformis and E. citriodora plantations during a year (except in March). In the three plantations, g(c) was positively logarithmically correlated with photosynthetically active radiation (PAR) (P < 0.001), with a higher sensitivity of g(c) to PAR during wet season than that of dry season. By contrast, a negative logarithmical correlation between g(c) and vapor pressure deficit (VPD) was observed, with a higher sensitivity of g(c) to VPD during the wet season. Additionally, a higher partial correlation coefficient between g(c) and VPD was observed during wet season, indicating that VPD played a more important role in regulating the behavior of stomata during wet season. In general, the sensitivity of g(c) to VPD decreased with the decreases of soil water content, but more manifest decreases were found in S. superba and E. citriodora forests than in A. auriculaeformis plantation, while the descend degree in S. superba and E. citriodora forests were equal. Overall, our results demonstrated that the native species S. superba is more suitable for re-vegetation in southern China than the exotic species A. auriculaeformis and E. citriodora.


Subject(s)
Environment , Trees/growth & development , Acacia/growth & development , China , Eucalyptus/growth & development , Photosynthesis , Plant Stems , Plant Transpiration , Seasons , Soil , Theaceae/growth & development , Water
16.
Chin Med J (Engl) ; 125(14): 2574-81, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22882942

ABSTRACT

BACKGROUND: The mechanical microenvironment of the chondrocytes plays an important role in cartilage homeostasis and in the health of the joint. The pericellular matrix, cellular membrane of the chondrocytes, and their cytoskeletal structures are key elements in the mechanical environment. The aims of this study are to measure the viscoelastic properties of isolated chondrons and chondrocytes from rabbit knee cartilage using micropipette aspiration and to determine the effect of aging on these properties. METHODS: Three age groups of rabbit knees were evaluated: (1) young (2 months, n = 10); (2) adult (8 months, n = 10); and (3) old (31 months, n = 10). Chondrocytes were isolated from the right knee cartilage and chondrons were isolated from left knees using enzymatic methods. Micropipette aspiration combined with a standard linear viscoelastic solid model was used to quantify changes in the viscoelastic properties of chondrons and chondrocytes within 2 hours of isolation. The morphology and structure of isolated chondrons were evaluated by optical microscope using hematoxylin and eosin staining and collagen-6 immunofluorescence staining. RESULTS: In response to an applied constant 0.3 - 0.4 kPa of negative pressure, all chondrocytes exhibited standard linear viscoelastic solid properties. Model predictions of the creep data showed that the average equilibrium modulus (E(∞)), instantaneous modulus (E(0)), and apparent viscosity (m) of old chondrocytes was significantly lower than the young and adult chondrocytes (P < 0.001); however, no difference was found between young and adult chondrocytes (P > 0.05). The adult and old chondrons generally possessed a thicker pericellular matrix (PCM) with more enclosed cells. The young and adult chondrons exhibited the same viscoelastic creep behavior under a greater applied pressure (1.0 - 1.1 kPa) without the deformation seen in the old chondrons. The viscoelastic properties (E(∞), E(0), and m) of young and adult chondrons were significantly greater than that observed in young and adult cells, respectively (P < 0.001). The adult chondrons were stiffer than the young chondrons under micropipette aspiration (P < 0.001). CONCLUSIONS: Our findings provide a theoretical model to measure the viscoelastic properties of the chondrons as a whole unit by micropipette aspiration, and further suggest that the properties of the chondrocytes and PCM have an important influence on the biomechanical microenvironment of the knee joint cartilage degeneration that occurs with aging.


Subject(s)
Aging/physiology , Cartilage, Articular/metabolism , Chondrocytes/metabolism , Animals , Elasticity , Rabbits , Viscosity
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