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Biomedical subjects

Yukihito Saito

Publications and source records attributed to Yukihito Saito.

12 recordsLinked to original sources
PubMed2006

Bronchial stump reinforcement with the intercostal muscle flap without adverse effects.

OBJECTIVE: Bronchopleural fistula is a serious complication of pulmonary resection. For anatomical reasons, lower lobectomy is thought to carry a higher risk for bronchopleural fistula. We investigated the efficacy of bronchial stump reinforcement with a pedicled intercostal muscle flap after lower lobectomy and compared the responses in patients treated with the flap, without the flap, and with other types of flap. We also investigated whether harvesting the intercostal muscle flap leads to an increase in blood loss during surgery and whether the type of flap influences chest-tube volume and pain after surgery. METHODS: One hundred and sixty-eight patients had lower or middle-lower lobectomy between January 1990 and December 2004. The bronchial stumps were treated in one of the three ways: covered with an intercostal muscle flap (116 patients, group A), not covered with a muscle flap (32 patients, group B), or covered with free fat or pleura (20 patients, group C). In a separate study, we compared the blood loss during surgery, and chest-tube volume and pain after surgery between patients treated with the intercostal muscle flap (23 patients) and non-intercostal muscle flap (32 patients). RESULTS: No patients in group A exhibited bronchopleural fistula, and two patients in group B and one patient in group C exhibited bronchopleural fistula. These differences were not significant. Blood loss, chest-tube volume, and pain score after surgery did not differ significantly between treatment groups. CONCLUSIONS: Bronchial stump reinforcement with the intercostal muscle flap after pulmonary resection is safe and effective when performed during lower and lower-middle lobectomy and does not increase the risk of complications.

Adult↗
PubMed2006

Pneumothorax after pneumonectomy: surgery with successful double lobe ventilation.

Contralateral pneumothorax is potentially lethal in patients who have undergone pneumonectomy. There are few reports about the diagnosis and treatment of this situation. This is a report of our experience with selective lobar ventilation of the middle and lower lobes using a guidewire and a bronchial blocker in the right upper bronchus of a patient who had previously undergone left pneumonectomy.

Bronchoscopy↗
PubMed2005

Airway stenting.

Interventional pulmonology, otherwise known as "airway stenting," has developed in the field of pulmonary medicine focused on using advanced bronchoscopic techniques to treat airway disorders. Tracheobronchial disorders can be caused by malignant or benign tumors, extrinsic compression, postintubation tracheal injuries, tracheobronchomalacia, or sequelae after tracheostomy. Tracheobronchial prostheses, known as airway stents, are used to palliate the effects of large airway obstruction. Specially designed stents are being used increasingly, not only in the airways, but also in the biliary tree, esophagus, urinary tract, and vascular system. There are two main types of airway stents currently available; tube stents made of silicone, and expandable metallic stents. Silicone stents are usually placed with the aid of a rigid bronchoscope while the patient is under general anesthesia. Unlike silicone stents, metal stents can be placed with a flexible bronchoscope. We examine the advantages and disadvantages of currently available stents and present our thoughts on the future development of airway stenting.

Airway Obstruction↗
PubMed2005

Long-term observation after simultaneous lung and intra-bone marrow-bone marrow transplantation.

BACKGROUND: Although lung transplantation is now an established treatment for end-stage lung diseases, allogeneic transplantation of parenchymal organs requires immunosuppressive therapy to prevent rejection. It has been reported that bone marrow transplantation (BMT) induces specific tolerance to donor organs. We have recently discovered a new method for BMT, which is called intra-bone marrow (IBM) BMT, in which bone marrow cells (BMCs) are injected directly into the bone marrow cavity. We demonstrate that IBM-BMT can be used to induce tolerance even in simultaneous lung transplantations in rats without administering any immunosuppressants. METHODS: Allogeneic lung transplantation was carried out from Brown Norway to Lewis rats. Simultaneously, IBM-BMT was carried out. RESULTS: Transplantation of nonirradiated lung or nontreated BMCs (T cell-containing BMCs) induced graft vs host disease. Therefore, the donor lung was irradiated, and T cells in the BMCs were depleted by anti-CD4, anti-CD5, and anti-CD8 antibodies plus anti-mouse antibody-coated magnetic beads. Lung allografts with conventional (intravenous) BMT failed to induce tolerance. However, the recipients treated with lung allografts plus IBM-BMT, which showed either mixed chimerism or full chimerism of hematopoietic cells, did not show symptoms of graft rejection or graft vs host disease, even without the use of immunosuppressants. CONCLUSIONS: These results suggest that simultaneous lung transplantation and IBM-BMT (but not conventional BMT) is effective in inducing persistent tolerance without the use of immunosuppressants.

Animals↗
PubMed2004

New tubular bioabsorbable knitted airway stent: feasibility assessment for delivery and deployment in a dog model.

PURPOSE: The aim of this study was to determine whether it is possible to deliver and deploy a new device, a poly-L-lactic acid (PLLA) tubular knitted airway stent, under bronchoscopic guidance in a dog model. DESCRIPTION: The delivery system consisted of a flexible balloon catheter (controlled radial expansion balloon dilator, M00558440, Boston Scientific Corporation, MA, USA) preloaded with a stent. A delivery catheter preloaded with a stent was advanced to a target point in the trachea under bronchoscopic guidance. Once the stent was positioned, the balloon was inflated for sixty seconds. The stent was in full contact with the tracheal wall upon deflation of the balloon. EVALUATION: The stents were successfully delivered into the tracheal lumen and successfully deployed in all dogs. CONCLUSIONS: This is the first study to prove the feasibility of delivering and deploying the PLLA stents in a dog model, using a balloon expansion technique. Further investigation with large numbers of subjects and long-term follow-up will be necessary to assess the utility of the bioabsorbable knitted tubular stent before clinical applications begin.

Absorbable Implants↗
PubMed2004

Endobronchial stents: past, present, and future.

Tracheobronchial prostheses, known as airway stents, are used to palliate the effects of large airway obstruction. The most common types of stents in current clinical use are made of silicone or metallic wire. An ideal stent should possess several characteristics: (1) it should be easy to insert and remove, if necessary; (2) it should be available in different sizes to match the obstruction; (3) once placed, it should maintain its position without migration; (4) it should be firm enough to resist compressive forces, yet have sufficient elasticity to conform to the airway contours; (5) it should be made of inert material, so as not to irritate the airway, precipitate infection, or promote granulation tissue; (6) it should exhibit the same characteristics of the normal airway so that mobilization of secretions is not impaired. We do not yet have an ideal airway stent that combines the advantages of silicone and metal stents. In this article, the advantages and disadvantages of currently available stents are reviewed, and some thoughts on the future development of airway stenting will be mentioned.

Journal Article↗
PubMed2003

A new method for establishing an intrapulmonary tumor in the rabbit.

OBJECTIVES: Local treatments against malignant intrapulmonary tumors, such as radiotherapy, photodynamic therapy, and laser ablation therapy, are sometimes used in preference to surgery or chemotherapy. The efficacy of such treatments is dependent not only on the pathological type of the primary tumor, but also on loco-regional settings such as location of the lesion and relationship between the tumor and surrounding organs as well as tissues. Therefore, in order to evaluate the efficacy of a newly developed local treatment, it is essential to have a model in which a tumor can be established at an intended location. In this study, we developed a model for the establishment of an intrapulmonary tumor, using the rabbit. METHODS: After induction of general anaesthesia, a catheter was inserted via the airway into the lung of a Japanese white rabbit, under X-ray guidance. The lung was then inoculated with a collagen gel matrix containing a suspension of VX2 cells derived from rabbit skin squamous cell carcinoma. Subsequent tumor growth was evaluated with X-ray imaging and pathological examination. RESULTS: Growth of a solitary tumor at the target site was pathologically confirmed in 9 of 12 rabbits that were inoculated with 1 x 10(8) cells. In addition, tumor growth could be followed in 8 of 9 rabbits by chest X-ray examination. That is, a solitary intrapulmonary tumor could be established in 8 of 12 animals (67%). CONCLUSION: The rabbit model reported here enables establishment of a solitary intrapulmonary tumor and thus can provide a suitable experimental setting for evaluation of local treatments of intrapulmonary tumors.

Animals↗
PubMed2002

A new bioabsorbable sleeve for staple-line reinforcement: report of a clinical experience.

PURPOSE: The most frequent and troublesome complication after resection of an emphysematous lung is persistent air leakage. This report describes our recent experience of using sleeves made of polyglycolic acid to reinforce staple-lines to reduce air leaks after resection of emphysematous lung. METHODS: We used bioabsorbable sleeves made of polyglycolic acid (PGA) for staple-line reinforcement during lung resections in 25 patients with emphysema. RESULTS: Immediately after stapling, no air leaks were detected in 20 patients (80%), although prolonged air leaks lasting for more than 7 days were observed in three patients (12.5%). CONCLUSION: PGA sleeves do not constitute a foreign body that stays in the host lung, and they require no rinsing at the time of clinical use. Therefore, the PGA sleeve could be a promising new material instead of non-absorbable materials and xenomaterials for staple-line reinforcement.

Absorbable Implants↗
PubMed2002

Prognostic significance of p53, Ki-67, VEGF and Glut-1 in resected stage I adenocarcinoma of the lung.

OBJECTIVES: The purpose of this study was to evaluate the prognostic significance of various biological factors in patients with resected stage I adenocarcinoma. METHODS: We immunohistochemically examined 47 specimens of surgically resected adenocarcinomas to evaluate the expression of the biological markers p53, Ki-67, vascular endothelial growth factor (VEGF) and glucose transporter-1 (Glut-1). Angiogenesis grade and tumor vessel invasion was also investigated. Actuarial survival was analyzed by the Kaplan-Meier method. Clinical variables and biological markers were analyzed using the Cox's proportional hazards model for multivariate analysis to identify independent prognostic factors. RESULTS: The overall survival rate for the whole series was 85.1% at 3 years and 71.9% at 5 years, with a median survival time of 73 months. Differentiation, Ki-67, Glut-1, VEGF, tumor vessel invasion and microvessel density (MVD) were significant prognostic factors by univariate analysis, with Glut-1 expression the most important prognostic factor for survival (P<0.0001). After multivariate analysis, only Glut-1 expression remained as a prognostic factor for survival. CONCLUSION: Glut-1 expression can be a predictor for prognosis in patients with resected stage I adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed2002

New tubular bioabsorbable knitted airway stent: biocompatibility and mechanical strength.

OBJECTIVE: This study examines the biocompatibility and suitability of a new tubular bioabsorbable knitted stent made of poly-L -lactic acid in normal rabbit airways and examines the mechanical strength of this stent in vitro. METHODS: A tubular knitted airway stent (group B, n = 15) made of poly-L -lactic acid wire was implanted operatively in New Zealand White rabbits intratracheally; silicone stents served as controls (group A, n = 8). The cervical trachea was exposed, and the stent was implanted. Up to 40 weeks after stent implantation, the rabbits were killed, at which time bronchoscopy, histologic examination, and scanning electron microscopic study was done. We tested poly-L -lactic acid stents and silicone stents for their mechanical strength in vitro. We subjected stents to area loads and measured their mechanical strengths. RESULTS: In group A, which received silicone stents, 3 (37.5%) rabbits died within 4 weeks of stent implantation as a result of airway obstruction by secretions inside the stent lumen. In group B, poly-L -lactic acid stents, 1 (6.7%) rabbit died 3 weeks after implantation because of weakness caused by anorexia. In the remaining animals, except for 1 animal with stent trouble, the bronchial lumen was fully open until the 40th week after implantation. After 40 weeks of follow-up, the stents disappeared, except for nonabsorbable suture in the bronchial wall. None of the animals in group B died of airway complication. Histologic examination and scanning electron microscopic examination of the group A silicone stents showed marked regression of ciliated cells under the stent. In group B the ciliated epithelium was preserved, and there were numerous capillary blood vessels in the submucosa. In scanning electron microscopy of the group B poly-L -lactic acid stents, the ciliated cells were preserved between the mesh holes of the stent. For diameters between 4 and 6 mm, the mechanical strength of silicone stents was greater than that of poly-L -lactic acid stents. However, the mechanical strength of poly-L -lactic acid stents increased as a function of their diameter. CONCLUSION: A new tubular bioabsorbable stent made of poly-L -lactic acid is biocompatible in normal rabbit airways, indicating that poly-L -lactic acid is a promising material for airway stents for clinical use.

Absorbable Implants↗
PubMed2002

Pulmonary metastasectomy for 165 patients with colorectal carcinoma: A prognostic assessment.

OBJECTIVE: The purpose of this study was to analyze our entire experience with pulmonary resection for metastatic colorectal carcinoma to determine prognostic factors and critically evaluate the potential role of extended metastasectomy. METHODS: We analyzed the postoperative survival of 165 patients who underwent curative pulmonary surgery at eight institutions in the Kansai region of western Japan (Kansai Clinical Oncology Group) from 1990 to 2000. RESULTS: Overall survivals at 5 and 10 years were 39.6% and 37.2%, respectively. Cumulative survival of patients who underwent simultaneous bilateral metastasectomy was significantly lower than that of the patients who underwent unilateral metastasectomy or sequential bilateral metastasectomy (P =.048). Five-year survival was 53.6% for patients without hilar or mediastinal lymph node metastasis, versus 6.2% at 4 years for patients with metastases (P <.001). Five-year survival of patients with a prethoracotomy carcinoembryonic antigen level less than 10 ng/mL was 42.7%, versus 15.1% at 4 years for patients with a carcinoembryonic antigen level 10 ng/mL or greater (P <.0001). Twenty-one patients underwent a second or third thoracotomy for recurrent colorectal carcinoma. Overall 5-year survival from the date of the second thoracotomy was 52.1%. The 34.1% 10-year survival for the 26 patients with hepatic metastasis resected before thoracotomy did not differ significantly from that of patients without hepatic metastases (P =.38). CONCLUSIONS: The status of the hilar or mediastinal lymph nodes and prethoracotomy carcinoembryonic antigen level were significant independent prognostic factors. Patients with pulmonary metastases potentially benefit from pulmonary metastasectomy even when there is a history of solitary liver metastasis. Careful follow-up is warranted, because patients with recurrent pulmonary metastases can undergo repeat thoracotomy with acceptable long-term survival. Simultaneous bilateral metastasectomy confers no survival benefit. Prospective studies may determine the significance of this type of pulmonary metastasectomy.

Adenocarcinoma↗