Investigation of the hydromechanical threshold of high-mobility group box 1 release from synovial cells and chondrocytes / 口腔疾病防治

Objective@#To investigate the effect of fluid flow shear stress (FFSS) on the fluid mechanic threshold of high-mobility group box 1 (HMGB1) release by synovial cells and chondrocytes. Moreover, the mechanism of chondrocyte and synovial cell damage induced by abnormal mechanical force was investigated to provide an experimental basis for exploring the pathogenesis and pathology of temporomandibular joint osteoarthritis.@*Methods@#With the approval of the Ethics Committee for Animal Experiments of the hospital, synovial tissue and cartilage tissue blocks were obtained from the knee joints of Sprague-Dawley (SD) rats, and synovial cells and chondrocytes were cultured and digested for subsequent experiments. Synovial cells and chondrocytes of 3-4 generations were acquired, and FFSS was applied to synovial and cartilage cells using a fluid shear mechanical device. The cells were divided according to the FFSS values of different sizes. Synovial cells were stimulated for 1 h with 1, 3, 5, or 10 dyn/cm2 of FFSS, and chondrocytes were stimulated for 1 h with 4, 8, 12, or 16 dyn/cm2 of FFSS. Resting cultures (0 dyn/cm2) were used as the control group. Changes in the morphology of the cells were observed. The expression and distribution of HMGB1 and interleukin-1β (IL-1β) were observed by immunohistochemistry. The expression of HMGB1 and IL-1β in the supernatant was analyzed by ELISA. The protein expression levels of intracellular HMGB1 and IL-1β were detected by Western blot.@*Results@#With increasing FFSS, the synovial cells and chondrocytes gradually swelled and ruptured, and the number of cells decreased. With increasing FFSS, the localizationof HMGB1 and IL-1β gradually shifted from the nucleus to the cytoplasm. In synovial cells, compared with those in the control group, the expression levels of HMGB1 and IL-1β were increased both in the supernatant and cells in the 1, 3, 5 and 10 dyn/cm2 intervention groups (P<0.01). In chondrocytes, compared with those in the control group, the expression levels of HMGB1 in the supernatant were increased in the 4, 12 and 16 dyn/cm2 intervention groups (P<0.05), and the protein expression levels of HMGB1 were significantly increased (P<0.01). The expression levels of HMGB1 in the supernatant were significantly increased in the 8 dyn/cm2 intervention groups (P<0.01); however, the protein expression levels of HMGB1 were significantly decreased. Compared with those in the control group, the expression levels of IL-1β in the supernatant gradually increased in the 4, 8, 12 and 16 dyn/cm2 intervention groups (P<0.01). With the exception of those in the 4 dyn/cm2 group, the protein expression levels of IL-1β gradually increased with increasing FFSS (P<0.05).@*Conclusion@#With increasing FFSS, synovial cells and chondrocytes gradually swelled and burst, and the hydromechanical thresholds of HMGB1 release were 1 dyn/cm2 and 8 dyn/cm2, respectively. Therefore, upon stimulation with a mechanical force, synovial damage was damaged before chondrocytes.

Preliminary Conception of Theory of Triple Energizer-nutrient-defense Loop / 中国实验方剂学杂志

The research on the essence of triple energizer has not reached a consensus. The correspondence between the existing understanding and the classical theory of triple energizer is still limited in terms of structure and function. According to the traditional theory， nutrient-defense takes channels as the main circulatory system， while the operation of nutrient-defense in the triple energizer remains unclear. Since little is known about the physical structure of the triple energizer， the role of triple energizer as a collection of other Zang-fu organs has been ignored in most cases. The new progress in anatomy paves the way for the research on the essence of triple energizer. The function and structure of triple energizer are similar to those of interstitium and interfacial fluid flow， which enriches our understanding of the macro and micro structures of triple energizer. The triple energizer is distributed throughout the body and composed of membrane and interstitial space. The material structure of triple energizer includes fiber scaffold， collagen fiber， mesenchymal stem cells， histiocytes， pericytes， and interstitial fluid. The functions of triple energizer include passing body fluids， operating nutrient-defense， distributing original Qi， and transmitting and changing pathogenic Qi. According to the available theories and research achievements， we put forward the concept of vertical and horizontal triple energizer， pointed out that triple energizer had independent structure and the features of Zang-fu organs， and preliminarily defined the spatial distribution of triple energizer. The relationship between channels and triple energizer is essential for discussing the operation of nutrient-defense. Telocyte （Tc） and telopod （Tp） has the characteristics of channels in function and structure. The connective tissue with the distribution of Tc and Tp belongs to the same material as the basic structure of interstitial/interfacial fluid flow system and the fibrous skeleton of interstitium. It is clear that channels and triple energizer have material commonality. From the operation paths of nutrient-defense， we proposed that channels may be soaked and attached in triple energizer and put forward the model of channels soaked and attached in triple energizer. By combining the circulation of nutrient-defense with the vertical and horizontal triple energize， we developed the theory of triple energizer-nutrient-defense loop to comprehensively describe the generation， transport， and metabolism of nutrient-defense in channels and triple energizer， aiming to provide a theoretical model for future studies of disease transmission and change from exterior to interior.

Preliminary Conception of Theory of Triple Energizer-nutrient-defense Loop / 中国实验方剂学杂志

The research on the essence of triple energizer has not reached a consensus. The correspondence between the existing understanding and the classical theory of triple energizer is still limited in terms of structure and function. According to the traditional theory， nutrient-defense takes channels as the main circulatory system， while the operation of nutrient-defense in the triple energizer remains unclear. Since little is known about the physical structure of the triple energizer， the role of triple energizer as a collection of other Zang-fu organs has been ignored in most cases. The new progress in anatomy paves the way for the research on the essence of triple energizer. The function and structure of triple energizer are similar to those of interstitium and interfacial fluid flow， which enriches our understanding of the macro and micro structures of triple energizer. The triple energizer is distributed throughout the body and composed of membrane and interstitial space. The material structure of triple energizer includes fiber scaffold， collagen fiber， mesenchymal stem cells， histiocytes， pericytes， and interstitial fluid. The functions of triple energizer include passing body fluids， operating nutrient-defense， distributing original Qi， and transmitting and changing pathogenic Qi. According to the available theories and research achievements， we put forward the concept of vertical and horizontal triple energizer， pointed out that triple energizer had independent structure and the features of Zang-fu organs， and preliminarily defined the spatial distribution of triple energizer. The relationship between channels and triple energizer is essential for discussing the operation of nutrient-defense. Telocyte （Tc） and telopod （Tp） has the characteristics of channels in function and structure. The connective tissue with the distribution of Tc and Tp belongs to the same material as the basic structure of interstitial/interfacial fluid flow system and the fibrous skeleton of interstitium. It is clear that channels and triple energizer have material commonality. From the operation paths of nutrient-defense， we proposed that channels may be soaked and attached in triple energizer and put forward the model of channels soaked and attached in triple energizer. By combining the circulation of nutrient-defense with the vertical and horizontal triple energize， we developed the theory of triple energizer-nutrient-defense loop to comprehensively describe the generation， transport， and metabolism of nutrient-defense in channels and triple energizer， aiming to provide a theoretical model for future studies of disease transmission and change from exterior to interior.

Blood-cerebrospinal fluid (CSF) barrier dysfunction means reduced CSF flow not barrier leakage - conclusions from CSF protein data / Disfunção da barreira hemato-liquórica significa redução do fluxo de líquido cefalorraquidiano, e não quebra de barreira - conclusões a partir de estudos sobre as proteínas do LCR

ABSTRACT Background: Increased concentrations of serum proteins in cerebrospinal fluid (CSF) are interpreted as blood-CSF barrier dysfunction. Frequently used interpretations such as barrier leakage, disruption or breakdown contradict CSF protein data, which suggest a reduced CSF flow rate as the cause. Results: Even the severest barrier dysfunctions do not change the molecular size-dependent selectivity or the interindividual variation of the protein transfer across barriers. Serum protein concentrations in lumbar CSF increase with hyperbolic functions, but the levels of proteins that do not pass the barrier remain constant (brain proteins) or increase linearly (leptomeningal proteins). All CSF protein dynamics above and below a lumbar blockade can also be explained, independent of their barrier passage, by a reduced caudally directed flow. Local accumulation of gadolinium in multiple sclerosis (MS) is now understood as due to reduced bulk flow elimination by interstitial fluid (ISF). Nonlinear change of the steady state in barrier dysfunction and along normal rostro-caudal gradients supports the diffusion/flow model and contradicts obstructions of diffusion pathways. Regardless of the cause of the disease, pathophysiological flow blockages are found in bacterial meningitis, leukemia, meningeal carcinomatosis, Guillain-Barré syndrome, MS and experimental allergic encephalomyelitis. In humans, the fortyfold higher albumin concentrations in early fetal development decrease later with maturation of the arachnoid villi, i.e., with beginning CSF outflow, which contradicts a relevant outflow to the lymphatic system. Respiration- and heartbeat-dependent oscillations do not disturb net direction of CSF flow. Conclusion: Blood-CSF and blood-brain barrier dysfunctions are an expression of reduced CSF or ISF flow rate.

RESUMO Introdução: Concentrações aumentadas de proteínas séricas no líquido cefalorraquidiano são interpretadas como disfunção da barreira (hemato-liquórica) sanguínea do LCR. Interpretações frequentemente usadas, como vazamento de barreira (quebra ou rompimento de barreira), rompimento ou quebra, contradiz os dados de proteína do LCR, que sugerem uma taxa de fluxo reduzida do LCR como a causa. Resultados: Mesmo as disfunções de barreira mais graves não alteram a seletividade dependente do tamanho molecular nem a variação interindividual da transferência de proteína através de barreiras. As concentrações de proteínas séricas no LCR lombar aumentam com as funções hiperbólicas, mas as proteínas que não passam a barreira permanecem constantes (proteínas do cérebro) ou aumentam linearmente (proteínas leptomeningeais). Toda a dinâmica das proteínas do LCR acima e abaixo de um bloqueio lombar também pode ser explicada, independente de sua passagem pela barreira, por um fluxo caudal reduzido. O acúmulo local de gadolínio na esclerose múltipla (EM) é agora entendido como decorrente da redução da eliminação do bulk flow pelo fluido intersticial (FIS). A mudança não linear do estado estacionário na disfunção da barreira e ao longo dos gradientes rostro-caudais normais apoia o modelo de difusão/fluxo e contradiz as obstruções das vias de difusão. Independentemente da causa da doença, os bloqueios fisiopatológicos do fluxo são encontrados na meningite bacteriana, leucemia, carcinomatose meníngea, síndrome de Guillain-Barré, EM e encefalomielite alérgica experimental. Em humanos, as concentrações de albumina quarenta vezes mais altas no desenvolvimento fetal inicial diminuem tarde com a maturação das vilosidades aracnoides, isto é, com o início do fluxo de LCR, o que contradiz um fluxo relevante para o sistema linfático. As oscilações dependentes da respiração e do batimento cardíaco não perturbam a direção do fluxo do LCR. Conclusão: As disfunções das barreiras hemato-liquórica e hemato-encefálica são uma expressão da redução da taxa de fluxo do LCR ou FIS.

The Trans-Scale Conduction Behavior of Fluid Stimulation in Loaded Bone / 医用生物力学

Objective To investigate the conduction behavior of fluid flow induced by physiological loads at different scales of bone. Method sThe multiscale bone models were established by using the COMSOL Multiphysics software, and the fluid behaviors were investigated at macro-, meso- and micro-scale. Results At macro-meso scale，the distribution of pore pressure and fluid velocity of osteon near the periosteum and endoosteum were different from that in other parts. Due to the different structure and material parameters at different layers, the loading and fluid pressure caused different biomechanical responses in the process of transferring from macro-scale to micro-scale. Conclusions The multi-scale layered modeling of bone structure-osteon-lacunae-bone canaliculi was established, which provided the theoretical reference for deeper understanding of fluid stimulation and mechanotransduction.

Thermodynamic bounds for existence of normal shock in compressible fluid flow in pipes

Abstract The present paper is concerned with the thermodynamic theory of the normal shock in compressible fluid flow in pipes, in the lights of the pioneering works of Lord Rayleigh and G. Fanno. The theory of normal shock in pipes is currently presented in terms of the Rayleigh and Fanno curves, which are shown to cross each other in two points, one corresponding to a subsonic flow and the other corresponding to a supersonic flow. It is proposed in this paper a novel differential identity, which relates the energy flux density, the linear momentum flux density, and the entropy, for constant mass flow density. The identity so obtained is used to establish a theorem, which shows that Rayleigh and Fanno curves become tangent to each other at a single sonic point. At the sonic point the entropy reaches a maximum, either as a function of the pressure and the energy density flux or as a function of the pressure and the linear momentum density flux. A Second Law analysis is also presented, which is fully independent of the Second Law analysis based on the Rankine-Hugoniot adiabatic carried out by Landau and Lifshitz (1959).

Development of LabVIEW-based loading system for cellular shear stress and its experimental validation / 医疗卫生装备

Objective To develop a cellular shear stress loading system with an adjustable stress mode and relevant parameters, and subsequently verify the effectiveness and feasibility of this system. Methods The hardware of the system was developed by using a peristaltic pump and self-designed multi-channel flow chamber, and the mode control program of shear stress based on LabVIEW was designed to control the device via RS485 interfacing and Modbus protocol. Additionally, the relationship between the shear stress and system parameters was calibrated, and finite element analysis was also conducted. Finally, the feasibility of the system was confirmed via the in vitro cell experiment. Results The mode and magnitude of shear stress of the system could be controlled via either the peristaltic pump or computer, and the cellular long-term effect was also able to be detected. The calibration results of the system indicated that the level of shear stress exhibited significantly linear positive correlation with the revolution of the peristaltic pump (P<0.001). Finite element analysis demonstrated that the level of shear stress on the slide was uniformly distributed and the result of simulation was accordant with calibration. Cytoskeleton staining suggested that cellular morphology of MLO-Y4 cells was changed, and microfilament increased and arrayed along fluid flow direction. Conclusion The system is stable and reliable enough to provide different loading modes and magnitude of cellular shear stress to offer a convictive platform of the research for different cellular stress signal transduction mecha-nisms.

Evaluation of Aqueductal Patency in Patients with Hydrocephalus: Three-Dimensional High-Sampling-Efficiency Technique (SPACE) versus Two-Dimensional Turbo Spin Echo at 3 Tesla

OBJECTIVE: To compare the accuracy of diagnosing aqueductal patency and image quality between high spatial resolution three-dimensional (3D) high-sampling-efficiency technique (sampling perfection with application optimized contrast using different flip angle evolutions [SPACE]) and T2-weighted (T2W) two-dimensional (2D) turbo spin echo (TSE) at 3-T in patients with hydrocephalus. MATERIALS AND METHODS: This retrospective study included 99 patients diagnosed with hydrocephalus. T2W 3D-SPACE was added to the routine sequences which consisted of T2W 2D-TSE, 3D-constructive interference steady state (CISS), and cine phase-contrast MRI (PC-MRI). Two radiologists evaluated independently the patency of cerebral aqueduct and image quality on the T2W 2D-TSE and T2W 3D-SPACE. PC-MRI and 3D-CISS were used as the reference for aqueductal patency and image quality, respectively. Inter-observer agreement was calculated using kappa statistics. RESULTS: The evaluation of the aqueductal patency by T2W 3D-SPACE and T2W 2D-TSE were in agreement with PC-MRI in 100% (99/99; sensitivity, 100% [83/83]; specificity, 100% [16/16]) and 83.8% (83/99; sensitivity, 100% [67/83]; specificity, 100% [16/16]), respectively (p < 0.001). No significant difference in image quality between T2W 2D-TSE and T2W 3D-SPACE (p = 0.056) occurred. The kappa values for inter-observer agreement were 0.714 for T2W 2D-TSE and 0.899 for T2W 3D-SPACE. CONCLUSION: Three-dimensional-SPACE is superior to 2D-TSE for the evaluation of aqueductal patency in hydrocephalus. T2W 3D-SPACE may hold promise as a highly accurate alternative treatment to PC-MRI for the physiological and morphological evaluation of aqueductal patency.

Oscillatory fluid flow elicits changes in morphology, cytoskeleton and integrin-associated molecules in MLO-Y4 cells, but not in MC3T3-E1 cells

Interstitial fluid flow stress is one of the most important mechanical stimulations of bone cells under physiological conditions. Osteocytes and osteoblasts act as primary mechanosensors within bones, and in vitro are able to respond to fluid shear stress, both morphologically and functionally. However, there is little information about the response of integrin-associated molecules using both osteoblasts and osteocytes. In this study, we investigated the changes in response to 2 hours of oscillatory fluid flow stress in the MLO-Y4 osteocyte-like cell line and the MC3T3-E1 osteoblast-like cell line. MLO-Y4 cells exhibited a significant increase in the expression of integrin-associated molecules, including OPN, CD44, vinculin and integrin avp3. However, there was no or limited increase observed in MC3T3-E1 osteoblast-like cells. Cell area and fiber stress formation were also markedly promoted by fluid flow only in MLO-Y4 cells. But the numbers of processes per cell remain unaffected in both cell lines.

Real-time measurement of dentinal fluid flow during desensitizing agent application / 대한치과보존학회지

OBJECTIVES: The aim of this study was to examine changes in the dentinal fluid flow (DFF) during desensitizing agent application and to compare permeability after application among the agents. MATERIALS AND METHODS: A Class 5 cavity was prepared to exposure cervical dentin on an extracted human premolar which was connected to a sub-nanoliter fluid flow measuring device (NFMD) under 20 cm water pressure. DFF was measured from before application of desensitizing agent (Seal&Protect, SP; SuperSeal, SS; BisBlock, BB; Gluma desensitizer, GL; Bi-Fluoride 12, BF) through application procedure to 5 min after application. RESULTS: DFF rate after each desensitizing agent application was significantly reduced when compared to initial DFF rate before application (p < 0.05). SP showed a greater reduction in DFF rate than GL and BF did (p < 0.05). SS and BB showed a greater reduction in DFF rate than BF did (p < 0.05). CONCLUSIONS: Characteristic DFF aspect of each desensitizing agent was shown in NFMD during the application procedure.

Real-time measurement of dentinal tubular fluid flow during and after amalgam and composite restorations / 대한치과보존학회지

The aim of this study was to measure the dentinal tubular fluid flow (DFF) during and after amalgam and composite restorations. A newly designed fluid flow measurement instrument was made. A third molar cut at 3 mm apical from the CEJ was connected to the flow measuring device under a hydrostatic pressure of 15 cmH2O. Class I cavity was prepared and restored with either amalgam (Copalite varnish and Bestaloy) or composite (Z-250 with ScotchBond MultiPurpose: MP, Single Bond 2: SB, Clearfil SE Bond: CE and Easy Bond: EB as bonding systems). The DFF was measured from the intact tooth state through restoration procedures to 30 minutes after restoration, and re-measured at 3 and 7days after restoration. Inward fluid flow (IF) during cavity preparation was followed by outward flow (OF) after preparation. In amalgam restoration, the OF changed to IF during amalgam filling and slight OF followed after finishing. In composite restoration, application CE and EB showed a continuous OF and air-dry increased rapidly the OF until light-curing, whereas in MP and SB, rinse and dry caused IF and OF, respectively. Application of hydrophobic bonding resin in MP and CE caused a decrease in flow rate or even slight IF. Light-curing of adhesive and composite showed an abrupt IF. There was no statistically significant difference in the reduction of DFF among the materials at 30 min, 3 and 7 days after restoration (P > 0.05).

CSF Flow Quantification of the Cerebral Aqueduct in Normal Volunteers Using Phase Contrast Cine MR Imaging

OBJECTIVE: To evaluate whether the results of cerebrospinal fluid (CSF) flow quantification differ according to the anatomical location of the cerebral aqueduct that is used and the background baseline region that is selected. MATERIALS AND METHODS: The CSF hydrodynamics of eleven healthy volunteers (mean age = 29.6 years) were investigated on a 1.5T MRI system. Velocity maps were acquired perpendicular to the cerebral aqueduct at three different anatomical levels: the inlet, ampulla and pars posterior. The pulse sequence was a prospectively triggered cardiac-gated flow compensated gradient-echo technique. Region-of-interest (ROI) analysis was performed for the CSF hydrodynamics, including the peak systolic velocity and mean flow on the phase images. The selection of the background baseline regions was done based on measurements made in two different areas, namely the anterior midbrain and temporal lobe, for 10 subjects. RESULTS: The mean peak systolic velocities showed a tendency to increase from the superior to the inferior aqueduct, irrespective of the background baseline region, with the range being from 3.30 cm/sec to 4.08 cm/sec. However, these differences were not statistically significant. In the case of the mean flow, the highest mean value was observed at the mid-portion of the ampulla (0.03 cm3/sec) in conjunction with the baseline ROI at the anterior midbrain. However, no other differences were observed among the mean flows according to the location of the cerebral aqueduct or the baseline ROI. CONCLUSION: We obtained a set of reference data of the CSF peak velocity and mean flow through the cerebral aqueduct in young healthy volunteers. Although the peak systolic velocity and mean flow of the CSF differed somewhat according to the level of the cerebral aqueduct at which the measurement was made, this difference was not statistically significant.

The Effect of Fluid Flow Induced Shear Stress on the Prostaglandin E2 and Nitric Oxide Production of Osteoblast / 대한정형외과연구학회지

It has been generally known that bone tissue responds to the mechanical stress with an adaptative change in the mass and the structure. Recently, the signal transduction pathways involved in fluid flow have been reported, and several mechanotransduction products were suggested. This study was designed to verify the prostaglandin E2(PGE2) and nitric oxide(NO) involving as the biomechanical transducing material of the osteoblast to the fluid flow stimuli. We have checked changes in PGE2 and NO production after applying fluid flow-induced shearing stress to the primary high-density monolayer cultures of chicken fetus osteoblasts. PGE2 and nitrite which is the stable end-product of nitric oxide oxidationas are measured spectrophotometrically, the former using enzyme immunoassay system and the latter using Griess reaction. As a result, PGE2 and NO production by osteoblast was increased after applying the fluid flow-induced shear stress: PGE2 production was increased accumulatively in response to the duration of stress. There were no significant changes in NO production after 6 hours of the stress, but production of NO was markedly increased only after 24 hours. From the above findings, it was confirmed that osteoblast increased the production of PGE2 and NO in respond to the fluid flow-induced shearing stress and that PGE2 production is an earlier response to mechanical stimuli than the production of NO.

Clinical Applications of Cine MR

Evaluation of intracranial CSF flow was accomplished by the use of cine MR technique. In the cine MR, there were two methods of evaluation in CSF flow pattern. Qualitative and quantitative methods were called magnitude reconstruction and phase contrast mapping method, respectively. The image of magnitude reconstruction method can demonstrate areas of decreased CSF flow and help explain the cause of hydrocephalus. The image of phase contrast mapping method is more sensitive to fluid motion and may increase utility in the future for analysis of fluid flow. Cine MR is capable of showing both normal and abnormal intracranial CSF flow. Such a study can be easily added as an extra pulse sequence at the end of a routinely acquired MR examination. We evaluated 2 cases of the normal pattern of pulsatile flow within subarachnoid space and 3 cases of abnormal patterns of CSF flow(communicating hydrocephalus: 2 cases, arachnoid cyst in posterior fossa: 1 case). These observations were compared with pre- and post-operative CSF flow state. In conditions which result in alterations of flow, cine MR shows either obstruction or excessively turbulent flow within the CSF pathways. In our studies, the most distinctive pathological finding was bulk flow in the aqueduct of Sylvius. The authors suggest that this technique can be applied in a wide range of conditions where CSF pathway is altered including hydrocephalus, evaluation of the function of the shunt system and communication between arachnoid cyst and subarachnoid space . Moreover correct diagnosis is possible in patients with hydrocephalus, in whom the exact level of CSF obstruction can be determined. We believe that surgical decisions can be aided by careful analysis of these CSF cine MR studies. We discuss the normal and abnormal CSF flow findings and indications of cine MR CSF flow technique with literature review.