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BACKGROUND: Embolization is a common treatment method for tumor-targeting, anti-organ hyper-function, and hemostasis. However, the injection of embolic agents largely depends on the experiences of doctors, and doctors need to work in an X-ray environment that hurts their health. Even for a well-trained doctor, complications such as ectopic embolism caused by excessive embolic agents are always inevitable. RESULTS: This paper established a flow control curve model for embolic injection based on local arterial pressure. The end-vessel network was simplified as a porous media. The hemodynamic changes at different injection velocities and embolization degrees were simulated and analyzed. Sponge, a typical porous medium, was used to simulate the blocking and accumulation of embolic agents by capillary networks in the in vitro experimental platform. CONCLUSIONS: The simulation and experimental results show that the local arterial pressure is closely related to the critical injection velocity of the embolic agent reflux at a certain degree of embolization. The feasibility of this method for an automatic embolic injection system is discussed. It is concluded that the model of the flow control curve of embolic injection can effectively reduce the risk of ectopic embolism and shorten the time of embolic injection. The clinical application of this model is of great value in reducing radiation exposure and improving the success rate of interventional embolization.
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Embolização Terapêutica , Injeções , Bandagens , Simulação por ComputadorRESUMO
Interventional embolization therapy is widely used for procedures such as targeted tumour therapy, anti-organ hyperactivity and haemostasis. During embolic agent injection, doctors need to work under X-ray irradiation environment. Moreover, embolic agent injection is largely dependent on doctors' experience and feelings, and over-injection of embolic agent can lead to reflux, causing ectopic embolism and serious complications. As an effective way to reduce radiation exposure and improve the success rate of interventional embolization therapy, embolic agent injection robot is highly anticipated, but how to decide the injection flow velocity of embolic agent is a problem that remains to be solved. On the basis of fluid dynamics simulation and experiment, we established an arterial pressure-injection flow velocity boundary curve model that can avoid reflux, which provides a design basis for the control of embolic agent injection system. An in vitro experimental platform for injection system was built and validation experiments were conducted. The results showed that the embolic agent injection flow speed curve designed under the guidance of the critical flow speed curve model of reflux could effectively avoid the embolic agent reflux and shorten the embolic agent injection time. Exceeding the flow speed limit of the model would lead to the risk of embolization of normal blood vessels. This paper confirms the validity of designing the embolic agent injection flow speed based on the critical flow speed curve model of reflux, which can achieve rapid injection of embolic agent while avoiding reflux, and provide a basis for the design of the embolic agent injection robot.
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Embolização Terapêutica , Embolização Terapêutica/métodosRESUMO
BACKGROUND: Osteoporosis is a common phenomenon in HIV patients on tenofovir treatment, but its underlying mechanisms remain to be explored. METHODS: Quantitative real-time PCR was performed to analyze the expression of miR-302, miR-101, miR-145 and osteoclast-specific genes in the serum of HIV patients treated with tenofovir and ZOL. ELISA was used to evaluate the expression of RANKL, SMAD3 and PRKACB in the serum of these patients. Luciferase assay was carried out to explore the inhibitory effects of miR-302, miR-101 and miR-145 on the expression of PRKACB, RANKL and SMAD3, respectively. Western blot was used to examine the expression of genes involved in NFκB and JNK signaling pathways. RESULTS: ZOL treatment significantly suppressed the expression of CTx and osteocalcin in HIV patients treated with tenofovir. The BMD loss of HIV patients treated with tenofovir was effectively hindered by ZOL treatment. Mechanistically, the expression of miR-302, miR-101, miR-145, RANKL, SMAD3 and PRKACB in the serum was remarkably activated by ZOL treatment. Luciferase assays showed that miR-302, miR-101 and miR-145 effectively suppressed the expression of PRKACB, RANKL and SMAD3, respectively, through binding to their 3' UTR. Furthermore, ZOL treatment notably restored the normal expression of osteoclastspecific genes while activating NFκB and JNK signaling pathways. CONCLUSION: The findings of this study demonstrated that administration of ZOL suppressed the expression of RANKL via modulating signaling pathways of miR-101-3p/RANKL, miR-302/PRKACB/RANKL and miR-145/SMAD3/RANKL. Furthermore, down-regulated expression of RANKL by ZOL treatment alleviated osteoporosis in HIV-positive subjects treated with tenofovir.
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Conservadores da Densidade Óssea/uso terapêutico , Infecções por HIV/tratamento farmacológico , Osteogênese/efeitos dos fármacos , Osteoporose/tratamento farmacológico , Ligante RANK/metabolismo , Ácido Zoledrônico/uso terapêutico , Adulto , Antirretrovirais/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/sangue , Feminino , Infecções por HIV/sangue , Infecções por HIV/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , MicroRNAs/sangue , Pessoa de Meia-Idade , Osteoclastos/efeitos dos fármacos , Osteoporose/sangue , Osteoporose/metabolismo , Ligante RANK/sangue , Proteína Smad3/sangue , Tenofovir/efeitos adversos , Ácido Zoledrônico/farmacologiaRESUMO
To improve the accuracy of common intelligent algorithms when identifying the parameters of geometric error in medical robots, this paper proposes an improved beetle antennae search algorithm (RWSAVSBAS). We first establish a model for the kinematic error in medical robots, and then add the random wandering behavior of the wolf colony algorithm to the search process of the beetle antennae search algorithm to strengthen its capability for local search. Following this, we improve the global convergence ability of the beetle antennae search algorithm by using the simulated annealing algorithm. We compare the accuracy of end positioning of the proposed algorithm with the frog-jumping algorithm and the beetle antennae search algorithm with variable step length through simulations. The results show that the proposed algorithm has a higher accuracy of convergence, and can significantly improve the accuracy of end positioning of the medical robot.
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Embolization is the prevailing therapy for tumor-targeting, anti-organ hyperfunction, and hemostasis. However, the injection of embolic agents largely depends on the experiences of doctors as assisted by X-ray, which will negate the health of the doctor. To avail embolization therapy feasible even in hospitals without experienced doctors and to prevent the doctors from exposion to X-ray, robotization is a promising alternative. To these ends, building the relationship between physiological parameters and hemodynamic parameters during embolization is crucial. This study takes the renal artery-kidney system of rabbits as the model case to investigate the dynamics of vascular embolization by numerical simulation using porous media for injection of embolic agents. The capillaries at the embolic site inside the kidney are modeled as porous media. The flow from the artery to the vein through the porous media is assumed as a viscous resistance fluid. The resistance, which increases with the increasing degree of embolization, is approached by CFD simulations. According to simulation results, a prediction model of flow resistance is established, enabling building the control law of an embolic agents injection robot. Experimental tests provide physical geometries and relevant parameters for the simulations as well as caliber to verify the simulation results. It is demonstrated that the currently proposed prediction model reflects the relationship between embolic agent injection and hemodynamic parameters reliably, enabling quantitative assessment of the degree of embolization with local blood pressure in the artery of the organ.
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Embolização Terapêutica , Robótica , Animais , Artérias , Injeções , Porosidade , CoelhosRESUMO
BACKGROUND: Under the transcriptional control of numerous factors and intracellular signals, mesenchymal stem cells (MSCs) can differentiate into various cell types, including adipocytes and osteoblasts. However, the precise cellular signaling factors that determine the cell fate of MSCs in bone marrow remain largely unknown. OBJECTIVE: In this review, we focus on the ties of PPAR-γ and Wnt signaling in MSC differentiation into adipocytes and osteoblasts. RESULTS: Peroxisome proliferator-activated receptor-γ (PPAR-γ) is well established as a prime inducer of adipogenesis, while the Wnt pathway is regarded as the master moderator of osteogenesis. A theoretical inverse relationship exists between adipogenic and osteogenic lineage commitment and differentiation: the differentiation toward an osteoblast phenotype occurs at the expense of an adipocyte phenotype. CONCLUSION: It has been proposed that the balance between osteogenic and adipogeneic MSC differentiation is disrupted in diverse areas of human health. Therefore, understanding the ties between PPAR- γand Wnt signaling in MSC differentiation has significant implications in diverse areas of human health, from obesity to osteoporosis to regenerative medicine.
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Adipogenia , Células-Tronco Mesenquimais/fisiologia , Osteogênese , PPAR gama/metabolismo , Transdução de Sinais , Proteínas Wnt/metabolismo , Animais , Humanos , Células-Tronco Mesenquimais/metabolismo , PPAR gama/fisiologia , Proteínas Wnt/fisiologiaRESUMO
STUDY DESIGN: Descriptive study. OBJECTIVES: This study aimed to evaluate the hidden blood loss (HBL) of patients who underwent lumbar fusion surgery for degenerative spine and to analyze its risk factors. SUMMARY OF BACKGROUND DATA: When planning transfusion strategies, blood loss calculation is important. However, in clinical practice, spine surgeons usually ignore the possibility that a large amount of HBL may occur after lumbar fusion surgery. MATERIALS AND METHODS: We studied the patients who underwent posterior lumbar fusion (PLF) surgery for degenerative spine from 2014 to 2015 in one institution. The patient's demographics, comorbid conditions, coagulation panel value, surgical time, number of levels fused, American Society of Anesthesiologists (ASA) classification, cell saver, preoperative hematocrit level, preoperative hemoglobin level, and postoperative complications were collected retrospectively. Pearson correlation analyses were used to find an association between patient characteristics and HBL. Multivariate linear analysis was used to determine independent risk factors of HBL. RESULTS: We reviewed 169 consecutive patients who underwent PLF surgery for degenerative spine in one institution. The mean amount of HBL was 588 mL, which was 39% of the total blood loss. On the basis of the model of multiple linear regression analysis, the multilevel fusion (P=0.001), surgical time (P=0.034), and fibrinogen level (P=0.027) were independent risk factors that contributed to HBL, but age of 60 years or above (P=0.110), postoperative complications (P=0.278), and cell saver were not (P=0.739). CONCLUSIONS: We conclude that a large amount of HBL may occur in patients who underwent PLF surgery for degenerative spine. In addition, significant hidden loss may have a correlation with postoperative mortality. Multilevel fused, surgical time, and fibrinogen level should be paid close attention when considering strategies of fluid infusion and blood transfusion.
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Perda Sanguínea Cirúrgica , Vértebras Lombares/cirurgia , Fusão Vertebral/efeitos adversos , Adulto , Vértebras Cervicais/cirurgia , Feminino , Humanos , Lordose/cirurgia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Fatores de RiscoRESUMO
Osteoporosis is a common age-related disorder characterized by low bone mass and deterioration in bone microarchitecture, leading to increased skeletal fragility and fracture risk. The pathophysiology of osteoporosis is multifactorial. It is related to the imbalance between osteoblasts and osteoclasts; reduced bone mass and increased adipogenesis in the bone marrow. Moreover, angiogenesis, inflammatory process and miRNAs have shown effects in the formation of osteoporosis. In the recent years, mesenchymal stem cells (MSCs) have been regarded as an excellent choice for cell-based tissue engineering therapy of osteoporosis. Growing evidence showed that paracrine effect has been considered as the predominant mechanism for the role of MSCs in tissue repair. Recently, many studies have proposed that MSCs-derived exosomes are effective for a variety of diseases like cancer, cardiovascular diseases, etc. However, whether the MSCs-derived exosomes could serve as a novel therapeutic tool for osteoporosis has not clearly described. In this review, we summarize the MSCs-derived exosomes and the relationship with osteogenesis, osteoclast differentiation, angiogenesis, immune processes and miRNAs. Finally, we suggest that MSCs-derived exosomes might be a promising therapeutic method for osteoporosis in the future.