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Interventional oncology offers minimally invasive treatments for malignant tumors for curative and palliative purposes based on the percutaneous insertion of needles or catheters into the target location under image guidance. Robotic systems have been gaining increasing attention as tools that provide potential advantages for image-guided interventions. Among the robotic systems developed for intervention, those relevant to the oncology field are mainly those for guiding or driving the needles in non-vascular interventional procedures such as biopsy and tumor ablation. Needle-guiding robots support planning the needle path and align the needle robotically according to the planned trajectory, which is combined with subsequent manual needle insertion by the physician through the needle guide. Needle-driving robots can advance the needle robotically after determining its orientation. Although a wide variety of robotic systems have been developed, only a limited number of these systems have reached the clinical phase or commercialization thus far. The results of previous studies suggest that such interventional robots have the potential to increase the accuracy of needle placement, facilitate out-of-plane needle insertion, decrease the learning curve, and reduce radiation exposure. On the other hand, increased complexity and costs may be a concern when using robotic systems compared with conventional manual procedures. Further data should be collected to comprehensively assess the value of robotic systems in interventional oncology.
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Procedimentos Cirúrgicos Robóticos , Tomografia Computadorizada por Raios X , Humanos , Tomografia Computadorizada por Raios X/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Agulhas , BiópsiaRESUMO
OBJECTIVES: To evaluate the accuracy of robotic CT-guided out-of-plane needle insertion in phantom and animal experiments. METHODS: A robotic system (Zerobot), developed at our institution, was used for needle insertion. In the phantom experiment, 12 robotic needle insertions into a phantom at various angles in the XY and YZ planes were performed, and the same insertions were manually performed freehand, as well as guided by a smartphone application (SmartPuncture). Angle errors were compared between the robotic and smartphone-guided manual insertions using Student's t test. In the animal experiment, 6 robotic out-of-plane needle insertions toward targets of 1.0 mm in diameter placed in the kidneys and hip muscles of swine were performed, each with and without adjustment of needle orientation based on reconstructed CT images during insertion. Distance accuracy was calculated as the distance between the needle tip and the target center. RESULTS: In the phantom experiment, the mean angle errors of the robotic, freehand manual, and smartphone-guided manual insertions were 0.4°, 7.0°, and 3.7° in the XY plane and 0.6°, 6.3°, and 0.6° in the YZ plane, respectively. Robotic insertions in the XY plane were significantly (p < 0.001) more accurate than smartphone-guided insertions. In the animal experiment, the overall mean distance accuracy of robotic insertions with and without adjustment of needle orientation was 2.5 mm and 5.0 mm, respectively. CONCLUSION: Robotic CT-guided out-of-plane needle insertions were more accurate than smartphone-guided manual insertions in the phantom and were also accurate in the in vivo procedure, particularly with adjustment during insertion. KEY POINTS: ⢠Out-of-plane needle insertions performed using our robot were more accurate than smartphone-guided manual insertions in the phantom experiment and were also accurate in the in vivo procedure. ⢠In the phantom experiment, the mean angle errors of the robotic and smartphone-guided manual out-of-plane needle insertions were 0.4° and 3.7° in the XY plane (p < 0.001) and 0.6° and 0.6° in the YZ plane (p = 0.65), respectively. ⢠In the animal experiment, the overall mean distance accuracies of the robotic out-of-plane needle insertions with and without adjustments of needle orientation during insertion were 2.5 mm and 5.0 mm, respectively.
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Rim/cirurgia , Músculo Esquelético/cirurgia , Agulhas , Imagens de Fantasmas , Punções/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Animais , Biópsia Guiada por Imagem/métodos , Rim/patologia , Músculo Esquelético/patologia , Robótica/métodos , Smartphone , Software , Cirurgia Assistida por Computador/métodos , Suínos , Tomografia Computadorizada por Raios X/métodosRESUMO
INTRODUCTION: This was a prospective, first-in-human trial to evaluate the feasibility and safety of insertion of biopsy introducer needles with our robot during CT fluoroscopy-guided biopsy in humans. MATERIALS AND METHODS: Eligible patients were adults with a lesion ≥ 10 mm in an extremity or the trunk requiring pathological diagnosis with CT fluoroscopy-guided biopsy. Patients in whom at-risk structures were located within 10 mm of the scheduled needle tract were excluded. Ten patients (4 females and 6 males; mean [range] age, 72 [52-87] years) with lesions (mean [range] maximum diameter, 28 [14-52] mm) in the kidney (n = 4), lung (n = 3), mediastinum (n = 1), adrenal gland (n = 1), and muscle (n = 1) were enrolled. The biopsy procedure involved robotic insertion of a biopsy introducer needle followed by manual acquisition of specimens using a biopsy needle. The patients were followed up for 14 days. Feasibility was defined as the distance of ≤ 10 mm between needle tip after insertion and the nearest lesion edge on the CT fluoroscopic images. The safety of robotic insertion was evaluated on the basis of machine-related troubles and adverse events according to the Clavien-Dindo classification. RESULTS: Robotic insertion of the introducer needle was feasible in all patients, enabling pathological diagnosis. There was no machine-related trouble. A total of 11 adverse events occurred in 8 patients, including 10 grade I events and 1 grade IIIa event. CONCLUSION: Insertion of biopsy introducer needles with our robot was feasible at several locations in the human body. KEY POINTS: ⢠Insertion of biopsy introducer needles with our robot during CT fluoroscopy-guided biopsy was feasible at several locations in the human body.
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Biópsia Guiada por Imagem/métodos , Radiografia Intervencionista/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Adulto , Biópsia por Agulha/métodos , Desenho de Equipamento , Estudos de Viabilidade , Feminino , Fluoroscopia/métodos , Humanos , Biópsia Guiada por Imagem/instrumentação , Masculino , Pessoa de Meia-Idade , Agulhas , Estudos Prospectivos , Robótica/métodos , Tomografia Computadorizada por Raios X/métodosRESUMO
Since 2012, we have been developing a remote-controlled robotic system (Zerobot®) for needle insertion during computed tomography (CT)-guided interventional procedures, such as ablation, biopsy, and drainage. The system was designed via a collaboration between the medical and engineering departments at Okayama University, including various risk control features. It consists of a robot with 6 degrees of freedom that is manipulated using an operation interface to perform needle insertions under CT-guidance. The procedure includes robot positioning, needle targeting, and needle insertion. Phantom experiments have indicated that robotic insertion is equivalent in accuracy to manual insertion, without physician radiation exposure. Animal experiments have revealed that robotic insertion of biopsy introducer needles and various ablation needles is safe and accurate in vivo. The first in vivo human trial, therefore, began in April 2018. After its completion, a larger clinical study will be conducted for commercialization of the robot. This robotic procedure has many potential advantages over a manual procedure: 1) decreased physician fatigue; 2) stable and accurate needle posture without tremor; 3) procedure automation; 4) less experience required for proficiency in needle insertion skills; 5) decreased variance in technical skills among physicians; and 6) increased likelihood of performing the procedure at remote hospitals (i.e., telemedicine).
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Radiologia Intervencionista/instrumentação , Procedimentos Cirúrgicos Robóticos/instrumentação , Robótica , Tomografia Computadorizada por Raios X , Humanos , Agulhas , Radiologia Intervencionista/métodos , Procedimentos Cirúrgicos Robóticos/métodos , UniversidadesRESUMO
BACKGROUND: Although rodent decidual mast cells (MCs) reportedly play an important role in implantation and placenta formation, the characterization of human decidual MCs has been not well clarified. The aims of this study were to investigate the distribution and characteristics of MCs in human decidua and to establish a culture system for decidua-derived MCs. METHODS: Decidual tissues were obtained from patients who underwent a legal elective abortion (6th week to 9th week of pregnancy), and decidual MCs were enzymatically dispersed. Cultured decidua-derived MCs were generated by culturing decidual cells with stem cell factor. An ultrastructural analysis of primary decidual MCs and cultured decidua-derived MCs was performed using a transmission electron microscope. Receptor and protease expression was analyzed using FACS. Histamine released from MCs was measured using enzyme immune assays. RESULTS: A larger proportion of tryptase positive(+) MCs in decidua was present on the maternal side. Both enzymatically dispersed decidual MCs and cultured decidua-derived MCs showed an FcεRIα+Kit+tryptase+chymase+ phenotype. Their granules contenting particles exhibited variable amounts of electron-lucent space separating electron-dense particles. Both enzymatically dispersed decidual MCs and cultured decidua-derived MCs released comparable amounts of histamine following FcεRI aggregation. CONCLUSIONS: The isolation method for MCs from decidua during early pregnancy and the culture system for decidua-derived MCs may enable the roles of decidual MC during pregnancy to be explored.
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Decídua/citologia , Mastócitos/metabolismo , Técnicas de Cultura de Células , Células Cultivadas , Quimases/metabolismo , Feminino , Histamina/metabolismo , Liberação de Histamina , Humanos , Mastócitos/ultraestrutura , Receptores de IgE/metabolismo , Membrana Sinovial/citologia , Triptases/metabolismoRESUMO
Purpose To evaluate the accuracy of the remote-controlled robotic computed tomography (CT)-guided needle insertion in phantom and animal experiments. Materials and Methods In a phantom experiment, 18 robotic and manual insertions each were performed with 19-gauge needles by using CT fluoroscopic guidance for the evaluation of the equivalence of accuracy of insertion between the two groups with a 1.0-mm margin. Needle insertion time, CT fluoroscopy time, and radiation exposure were compared by using the Student t test. The animal experiments were approved by the institutional animal care and use committee. In the animal experiment, five robotic insertions each were attempted toward targets in the liver, kidneys, lungs, and hip muscle of three swine by using 19-gauge or 17-gauge needles and by using conventional CT guidance. The feasibility, safety, and accuracy of robotic insertion were evaluated. Results The mean accuracies of robotic and manual insertion in phantoms were 1.6 and 1.4 mm, respectively. The 95% confidence interval of the mean difference was -0.3 to 0.6 mm. There were no significant differences in needle insertion time, CT fluoroscopy time, or radiation exposure to the phantom between the two methods. Effective dose to the physician during robotic insertion was always 0 µSv, while that during manual insertion was 5.7 µSv on average (P < .001). Robotic insertion was feasible in the animals, with an overall mean accuracy of 3.2 mm and three minor procedure-related complications. Conclusion Robotic insertion exhibited equivalent accuracy as manual insertion in phantoms, without radiation exposure to the physician. It was also found to be accurate in an in vivo procedure in animals. © RSNA, 2017 Online supplemental material is available for this article.
Assuntos
Agulhas , Radiografia Intervencionista/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Desenho de Equipamento , Imagens de Fantasmas , Radiografia Intervencionista/instrumentação , Procedimentos Cirúrgicos Robóticos/instrumentação , Suínos , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
BACKGROUND: Isolated prolongation of activated partial thromboplastin time (APTT) has various causes including inheritable bleeding disorders, and has medical significance as it can lead to the cancelation of surgery. However, even an emergency surgery can be conducted in a patient presenting with severe APTT prolongation, provided careful evaluation and appropriate measures are taken. Hence, the identification of the underlying etiology of the prolonged APTT is crucial. To date, little evidence exists regarding the prevalence of isolated APTT prolongation in Japanese patients undergoing surgery. Herein, we aimed to clarify the prevalence of isolated prolongation of APTT in the preoperative setting and to identify the reasons underlying isolated, severely prolonged APTT. METHODS: Preoperative coagulation data of all elective and emergent patients who presented to the anesthetic department between January 1, 2020, and June 30, 2023, were retrospectively collected. Isolated prolongation of APTT was defined as an APTT ≥ 37 s with an international normalized ratio of prothrombin time < 1.2. The underlying etiology of the patient with isolated, severely prolonged APTT (≥ 46 s) was investigated, and canceled surgical procedures in relation to the isolated APTT prolongation were searched. RESULTS: Overall, 10,684 measurements from 9413 patients were included, of which 725 (6.8%) were identified as having isolated APTT prolongation. The reasons for the severely prolonged APTT (n = 60) were miscellaneous, with the most frequently detected etiology being antiphospholipid antibody positivity. Preoperative isolated APTT prolongation contributed to the cancellation of surgery in elective five cases. CONCLUSIONS: We clarified the prevalence of preoperative isolated prolongation of APTT. The presence of antiphospholipid antibody was the most frequently detected etiology of the patient with isolated, severely prolonged APTT. The present study provides an important dataset regarding the isolated prolongation of APTT in East Asian patients undergoing surgery.
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Bacillus cereus sphingomyelinase (Bc-SMase) induces hemolysis of sheep erythrocytes which contain large amounts of sphingomyelin. We investigated the mechanism of this hemolysis in comparison to that induced by Clostridium perfringens alpha-toxin. Pertussis toxin, a Gi-specific inhibitor, N-oleoylethernolamine, a ceramidase inhibitor, and dihydrosphingosine, a sphingosine kinase inhibitor, did not inhibit the hemolysis by Bc-SMase, but did inhibit that by alpha-toxin. Bc-SMase broadly bound to whole membranes, and alpha-toxin specifically bound to the detergent-resistant membrane fractions, lipid rafts. The level of ceramide production induced by Bc-SMase in sheep erythrocytes was 6- to 15-fold that induced by alpha-toxin, when the extent of the hemolysis by Bc-SMase was the same as that by the toxin. However, the level of ceramide production induced by Bc-SMase in SM-liposomes was equal to that triggered by the toxin, when the carboxyl fluorescein-release from liposomes induced by Bc-SMase was the same as that induced by alpha-toxin. Confocal laser microscopy showed that treatment of the cells with Bc-SMase resulted in the formation of ceramide-rich domains. A photobleaching analysis suggested that treatment of the cells with Bc-SMase leads to a reduction in membrane fluidity. These results show that Bc-SMase-induced hemolysis of sheep erythrocytes is related to the formation of interface between ceramide-rich domains and ceramide-poor domains through production of ceramide from SM.
Assuntos
Bacillus cereus/enzimologia , Membrana Eritrocítica/química , Hemólise , Microdomínios da Membrana/química , Esfingomielina Fosfodiesterase/química , Esfingosina/análogos & derivados , Animais , Bacillus cereus/genética , Toxinas Bacterianas/química , Proteínas de Ligação ao Cálcio/química , Ceramidas/química , Fluidez de Membrana , Toxina Pertussis/química , Ovinos , Esfingomielina Fosfodiesterase/genética , Esfingosina/química , Fosfolipases Tipo C/químicaRESUMO
AIM: To investigate the changes in the maternal immune system at term pregnancy, we studied the expression of natural cytotoxicity receptors (NCRs) and the cytokine production of NK cells in term placenta decidua and peripheral blood. METHODS: Term decidua and peripheral blood were taken from patients undergoing elective cesarean section. The lymphocytes were separated using density gradient centrifugation (DGC) from peripheral blood and were separated from decidua using DGC after enzyme digestion. These cells were stained with FITC anti-CD56 and Per-CP anti-CD3 monoclonal antibodies, and the NCRs were stained with PE-conjugated anti-NKG2D, NKp46, NKp30, and NKp44 monoclonal antibodies. Cytokines, including IFN-γ, TNF-α, IL-10, and TGF-ß, were stained and then analyzed by flow cytometry. RESULTS: There were fewer cells positive for NKG2D, NKp46, and NKp30 among CD56+CD3- cells in deciduas than in peripheral blood, but the percentages of NKp44-positive cells in CD56+CD3- lymphocytes in deciduas tended to be higher. CONCLUSION: The decreased expression of some NCRs in deciduas may be related to decreased cytotoxicity at term pregnancy, but the increased expression of NKp44 may affect the increased cytokine production in the decidua. Similarly, the expression of NCRs in the decidua may be connected to the maintenance of pregnancy at term.
Assuntos
Decídua/imunologia , Células Matadoras Naturais/metabolismo , Gravidez/imunologia , Receptores Desencadeadores da Citotoxicidade Natural/metabolismo , Adulto , Feminino , Citometria de Fluxo , Humanos , Células Matadoras Naturais/imunologia , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Receptor 1 Desencadeador da Citotoxicidade Natural/metabolismo , Receptor 2 Desencadeador da Citotoxicidade Natural/metabolismo , Receptor 3 Desencadeador da Citotoxicidade Natural/metabolismo , Adulto JovemRESUMO
OBJECTIVE: To evaluate the accuracy of robotic insertion of various ablation needles at various locations under computed tomography (CT) guidance in swine. MATERIALS AND METHODS: The robot was used for CT-guided insertion of four ablation needles, namely a single internally cooled radiofrequency ablation (RFA) needle (Cool-tip), a multi-tined expandable RFA needle (LeVeen), a cryoablation needle (IceRod), and an internally cooled microwave ablation needle (Emprint). One author remotely operated the robot with the operation interface in order to orient and insert the needles under CT guidance. Five insertions of each type of ablation needle towards 1.0-mm targets in the liver, kidney, lung, and hip muscle were attempted on the plane of an axial CT image in six swine. Accuracy of needle insertion was evaluated as the three-dimensional length between the target centre and needle tip. The accuracy of needle insertion was compared according to the type of needle used and the location using one-way analysis of variance. RESULTS: The overall mean accuracy of all four needles in all four locations was 2.8â¯mm. The mean accuracy of insertion of the Cool-tip needle, LeVeen needle, IceRod needle, and Emprint needle was 2.8â¯mm, 3.1â¯mm, 2.5â¯mm, and 2.7â¯mm, respectively. The mean accuracy of insertion into the liver, kidney, lung, and hip muscle was 2.7â¯mm, 2.9â¯mm, 2.9â¯mm, and 2.5â¯mm, respectively. There was no significant difference in insertion accuracy among the needles (Pâ¯=â¯.38) or the locations (Pâ¯=â¯.53). CONCLUSION: Robotic insertion of various ablation needles under CT guidance was accurate regardless of type of needle or location in swine.
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Biópsia por Agulha/instrumentação , Ablação por Cateter/instrumentação , Radiografia Intervencionista , Procedimentos Cirúrgicos Robóticos , Tomografia Computadorizada por Raios X , Animais , Ablação por Cateter/métodos , Modelos Animais de Doenças , Quadril/diagnóstico por imagem , Humanos , Rim/diagnóstico por imagem , Fígado/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Imagens de Fantasmas , Radiografia Intervencionista/instrumentação , Radiografia Intervencionista/métodos , Reprodutibilidade dos Testes , Procedimentos Cirúrgicos Robóticos/instrumentação , Procedimentos Cirúrgicos Robóticos/métodos , Suínos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodosRESUMO
OBJECTIVE: To evaluate a modified single-access method of contained power morcellation performed with a single-access laparoscopic device and a new cordless electric morcellator. The study was a preliminary assessment of the feasibility and safety of the new technique. STUDY DESIGN: A single university hospital observational study involving patients who underwent either laparoscopic myomectomy or laparoscopic hysterectomy. We evaluated the operative results, time required for the contained morcellation, any occurrence of bag leakage, and any complications. RESULTS: The new contained power morcellation technique was applied in 12 patients (9 undergoing laparoscopic myomectomy and 3 undergoing laparoscopic hysterectomy). The mean bag introduction time was 21.8min (range, 14-37min); mean in-bag morcellation time was 11.5min (range, 1-26min); and mean total morcellation time was 36.8min (range, 19-66min). Visual inspection revealed no bag damage. There were no postoperative complications. CONCLUSION: Single-site in-bag morcellation performed with our new technique requires neither bag penetration nor piercing with a trocar and thus may prove beneficial for preventing spillage and dissemination of unwanted cells and tissue.
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Histerectomia/métodos , Laparoscopia/métodos , Morcelação/métodos , Miomectomia Uterina/métodos , Útero/cirurgia , Adulto , Feminino , Humanos , Histerectomia/instrumentação , Laparoscopia/instrumentação , Pessoa de Meia-Idade , Morcelação/instrumentação , Resultado do Tratamento , Miomectomia Uterina/instrumentaçãoRESUMO
The main aim of the present study is to determine the optimal administration period of cisplatin with regards to its toxic effects on ovarian morphology in the repeated-dose toxicity study. Cisplatin was administered to female SD rats intraperitoneally once daily at dose levels of 0.25, 0.5, 1.0 and 2.0 mg/kg for 2 weeks, or at dose levels of 0.125, 0.25 and 0.5 mg/kg for 4 weeks in the repeated-dose toxicity study. In the female fertility study, 0.25, 0.5 and 1.0 mg/kg of cisplatin were administered in the same manner from 14 days prior to mating to Day 7 of gestation. In the repeated-dose toxicity study, a decrease in large follicle, an increase in atresia of medium and large follicles, and/or a decrease in currently formed corpus luteum were observed in animals receiving 1.0 and 2.0 mg/kg for 2 weeks, and decreases in small and/or large follicles and an increase in atresia of large follicle were observed in animals receiving 0.25 and 0.5 mg/kg for 4 weeks on the histopathological examination of the ovaries. In the female fertility study, the copulation and fertility indices in the animals receiving 1.0 mg/kg tended to be lower than those in the control animals. In conclusion, histopathological changes in the ovary that were attributable to cisplatin dosing were detected by detailed observation of the ovary in the 2-week study; and therefore, a 2-week administration period is sufficient to evaluate the ovarian toxicity of cisplatin.
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Antineoplásicos/toxicidade , Cisplatino/toxicidade , Fertilidade/efeitos dos fármacos , Ovário/efeitos dos fármacos , Testes de Toxicidade/métodos , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Cisplatino/administração & dosagem , Copulação/efeitos dos fármacos , Esquema de Medicação , Ingestão de Alimentos/efeitos dos fármacos , Implantação do Embrião/efeitos dos fármacos , Embrião de Mamíferos/efeitos dos fármacos , Feminino , Injeções Intraperitoneais , Japão , Longevidade/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/metabolismo , Folículo Ovariano/patologia , Ovário/patologia , Gravidez , Parcerias Público-Privadas , Ratos , Ratos Sprague-Dawley , Sociedades Científicas , Útero/efeitos dos fármacos , Útero/patologia , Vagina/efeitos dos fármacos , Vagina/patologiaRESUMO
Clostridium perfringens alpha-toxin induces the hemolysis of sheep erythrocytes by activating the metabolism of sphingomyelin (SM) via a GTP binding protein in membranes. alpha-Toxin stimulated the formation of 15-N-nervonoyl sphingosine (C24:1-ceramide), which was identified by positive ion fast atom bombardment-MS and 1H-NMR spectroscopy. C24:1-ceramide stimulated the toxin-induced hemolysis of saponin-pretreated sheep erythrocytes and increased the production of sphingosine 1-phosphate (S1P) in the cells, but N-lignoceroyl sphingosine did not. These events elicited by the toxin in the presence of C24:1-ceramide were significantly attenuated by treatment with dihydrosphingosine, a sphingosine kinase inhibitor. TLC showed that the level of C24:1-ceramide was highest among the ceramides with an unsaturated bond in the fatty acyl chain in the detergent-resistant membranes (DRMs). The toxin specifically bound to DRMs rich in cholesterol, resulting in the hydrolysis of N-nervonoic sphingomyelin (C24:1-SM) in DRMs. Treatment of the cells with pertussis toxin (PT) inhibited the alpha-toxin-induced formation of C24:1-ceramide from C24:1-SM in DRMs and hemolysis, indicating that endogenous sphingomyelinase, which hydrolyzes C24:1-SM to C24:1-ceramide, is controlled by PT-sensitive GTP binding protein in membranes. These results show that the toxin-induced metabolism of C24:1-SM to S1P in DRMs plays an important role in the toxin-induced hemolysis of sheep erythrocytes.
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Toxinas Bacterianas/toxicidade , Proteínas de Ligação ao Cálcio/toxicidade , Eritrócitos/fisiologia , Hemólise , Esfingomielinas/metabolismo , Fosfolipases Tipo C/toxicidade , Animais , Detergentes/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/fisiologia , Eritrócitos/efeitos dos fármacos , Cinética , Ovinos , Esfingosina/análogos & derivados , Esfingosina/farmacologiaRESUMO
Clostridium perfringens alpha-toxin induces the generation of superoxide anion (O2(-)) via production of 1,2-diacylglycerol (DG) in rabbit neutrophils. The mechanism of the generation, however, remains poorly understood. Here we report a novel mechanism for the toxin-induced production of O2(-) in rabbit neutrophils. Treatment of the cells with the toxin resulted in tyrosine phosphorylation of a protein of about 140 kDa. The protein reacted with anti-TrkA (nerve growth factor high-affinity receptor) antibody and bound nerve growth factor. Anti-TrkA antibody inhibited the production of O2(-) and binding of the toxin to the protein. The toxin induced phosphorylation of 3-phosphoinositide-dependent protein kinase 1 (PDK1). K252a, an inhibitor of TrkA receptor, and LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), reduced the toxin-induced production of O2(-) and phosphorylation of PDK1, but not the formation of DG. These inhibitors inhibited the toxin-induced phosphorylation of protein kinase C theta (PKCtheta). U73122, a phospholipase C (PLC) inhibitor, and pertussis toxin inhibited the toxin-induced generation of O2(-) and formation of DG, but not the phosphorylation of PDK1. These observations show that the toxin independently induces production of DG through activation of endogenous PLC and phosphorylation of PDK1 via the TrkA receptor signaling pathway and that these events synergistically activate PKCtheta in stimulating an increase in O2(-). In addition, we show the participation of mitogen-activated protein kinase-associated signaling events via activation of PKCtheta in the toxin-induced generation of O2(-).