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Biomedical subjects

K Nezu

Publications and source records attributed to K Nezu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Thoracoscopic lung volume reduction surgery for emphysema. Evaluation using ventilation-perfusion scintigraphy.

Thoracoscopic lung volume reduction surgery was conducted in 28 consecutive patients (bilateral 21, unilateral 7). The bilateral procedure was conducted simultaneously in 16 and as a planned staged approach in 5, using stapler resection with Nd:YAG laser ablation. Perfusion and ventilation scintigraphy were used to evaluate status before and after surgery. One operative death (3.6%) due to pneumonia occurred after a simultaneous bilateral procedure. Three to 6 months after surgery, the forced expiratory volume in 1 second (FEV1.0) had improved an average of 44% after the bilateral procedure and 17% after unilateral. Improved ventilation and perfusion distribution in the lower lung field correlated significantly with improved dyspnea scale (p < 0.01). Mean transit time was shortened significantly in each lung field (p < 0.01). Improved mean transit time correlated significantly with improved FEV1.0 and maximum oxygen consumption (VO2max) (p < 0.05). In conclusion, we found that bilateral thoracoscopic lung volume reduction surgery produces short-term functional outcomes superior to those of the unilateral procedure, and should be considered the procedure of choice for most patients. Ventilation and perfusion scintigraphy are useful both in determining target areas for resection and in evaluating lung volume reduction surgery effects.

Aged↗
PubMed1999

Body composition analysis by dual energy X-ray absorptiometry and exercise performance in underweight patients with COPD.

STUDY OBJECTIVES: The aim of this study was to examine the effect of body composition on maximal exercise performance in patients with COPD. METHODS: The study was carried out on 27 patients with COPD and was confirmed by pulmonary function testing. Body composition was measured by dual energy x-ray absorptiometry (DXA). Exercise performance was conducted on a cycle ergometer and was measured as maximal work rate (WRmax) and maximal oxygen uptake (VO2max). Bone mineral content (BMC), lean mass (LEAN), and fat mass (FAT) were assessed by DXA and were expressed as a percentage of ideal body weight, BMC, LEAN, and FAT. RESULTS: LEAN% correlated significantly with VO2max (r = 0.66, p = 0.0002) and WRmax (r = 0.70, p < 0.0001). No significant correlation was found between FAT% and exercise performance. By stepwise regression analysis, variables significantly contributing to WRmax and VO2max were LEAN% and the maximal voluntary ventilation. Total variance explained in these models was 81% for WRmax aid 82% for VO2max. CONCLUSION: Lean mass was an important determinant of maximal exercise performance in patients with COPD.

Absorptiometry, Photon↗
PubMed1999

Enhanced expression of Tie2, its ligand angiopoietin-1, vascular endothelial growth factor, and CD31 in human non-small cell lung carcinomas.

Expression of angiogenesis-associated genes was compared in 32 primary non-small cell lung carcinoma samples (14 adenocarcinomas, 17 squamous cell carcinomas, and 1 large cell carcinoma) and paired adjacent noncancerous lung tissues using a multiprobe RNase protection assay. Levels of Tie2, angiopoietin (Ang)-1, vascular endothelial growth factor (VEGF), and CD31 mRNAs were higher in cancers than in adjacent noncancerous tissues, in contrast to the fms-like tyrosine kinase (Flt)-1, Flt-4, Tie1, thrombin receptor, endoglin, and VEGF-C, for which no differences were evident. Overexpression did not seem to differ with histological type and pathological stage. Significant positive correlations were found between mRNA expression of Ang-1 and those of Tie2 and CD31, and that of VEGF and those of Flt-1 and CD31. These findings suggest that Ang-1 and VEGF are important angiogenic factors in human non-small cell lung carcinomas.

Adult↗
PubMed1999

[Re-coronary artery bypass grafting using a MIDCAB technique in a patient with a patent RITA-LAD graft].

In a patient with a patent RITA-LAD (right internal thoracic artery-left anterior descending artery) graft, re-CABG (re-coronary artery bypass grafting) with re-median sternotomy has been a high risk procedure. A 56-year-old male underwent 4-CABG (RITA-LAD, LITA-Dx, SVG-PL, and SVG-RCA) nine years ago. Coronary angiography showed that the RITA-LAD graft was well patent, but there was 95% stenosis distal to RITA-LAD anastomosis site. We performed re-CABG (right gastroepiploic artery-LAD; RGEA-LAD), using MIDCAB (minimally invasive direct coronary artery bypass) technique with neither re-median sternotomy nor cardiopulmonary bypass. The right gastroepiploic artery was harvested through a small upper median laparotomy and anastomosed to LAD through a small left anterior thoracotomy. The postoperative course was uneventful. This technique seems to be useful for re-revascularization of the LAD in a patient with a patent RITA-LAD graft.

Coronary Artery Bypass↗
PubMed1998

Which type of diffuse emphysema is adequately contracted by the Nd:YAG laser. An ex-vivo experiment.

Diffusely emphysematous lungs are not always effectively contracted by laser therapy; however, which type of diffuse emphysema that responds to laser therapy remains unclear. We macroscopically and histopathologically examined human lung tissue, which was resected from patients with carcinoma, after irradiation with an Nd:YAG laser. Forty-six lung lobes were irradiated with a non-contact mode Nd:YAG laser at a power setting 15 watts. Macroscopically, twenty samples of normal lungs revealed moderate contraction, fourteen samples of predominantly centrilobular diffuse emphysema showed significant contraction, and eight samples of predominantly panlobular diffuse emphysema with a slight elastic network showed slight contraction. Histopathologically, the normal lungs showed amorphous change of the collagen and severely contracted elastic fibers (amorphous degeneration) at the pleura and some parenchymal coagulation; the predominantly centrilobular diffuse emphysema showed contraction of elastic fibers and collagen (coagulative degeneration) in the pleura and adequate contraction of the elastic fibers in the parenchyma and the predominantly panlobular diffuse emphysema showed only slight coagulation of the visceral pleura and very little coagulation of the parenchyma. On ex-vivo lung, panlobular emphysema was inadequately contracted by laser therapy, due to elastic recoil. Centrilobular emphysema responded to laser treatment, due to the severe contraction of the elastic fibers.

Elastic Tissue↗
PubMed1998

Tracheal replacement with cryopreserved tracheal allograft: experiment in dogs.

BACKGROUND: It has been difficult to perform tracheal allotransplantation without immunosuppression. To determine whether cryopreserved trachea can be used in tracheal replacement, we evaluated the viability of cryopreserved tracheal allografts in a canine model of immunosuppressant-free transplantation. METHODS: Cryopreserved tracheal allografts, which had been frozen to -80 degrees C in a programmed freezer and then stored in liquid nitrogen (-196 degrees C) (group 1, n = 6), fresh tracheal autografts (group 2, n = 5), and fresh tracheal allografts (group 3, n = 4) were transplanted into the thoracic segment of the trachea using an omental flap without immunosuppressive agents. RESULTS: All dogs in groups 1 and 2 survived, but in group 3, all 4 died of airway obstruction between 1 month and 2 months after operation. Histologically, the cryopreserved allografts displayed normal epithelium and cartilage, but the fresh allografts showed chronic inflammatory changes, no epithelium, and no cartilage. CONCLUSIONS: Cryopreserved tracheal allografts maintain their structural integrity after transplantation. The cryopreservation process seems to reduce the allogenic response of the trachea in canine models. Therefore, we believe the cryopreserved tracheal allograft is an excellent choice for tracheal replacement.

Airway Obstruction↗
PubMed1998

Epithelial regeneration and preservation of tracheal cartilage after tracheal replacement with cryopreserved allograft in the rat.

OBJECTIVE: We investigated the origin of the epithelium in transplanted cryopreserved tracheal allografts in rats and tried to clarify the mechanism by which immunogenicity is reduced in this procedure. METHODS: Tracheal transplantation was performed with PVG rats (allele at the RT1 locus: c) used as donors and ACI rats (allele at the RT1 locus: a) as recipients. After resection of a 5-ring segment of the cervical trachea of an ACI rat, the trachea was reconstructed with the cryopreserved tracheal segment of a PVG rat (n = 6). No immunosuppressive agents or steroids were given. Histologic changes were determined and immunohistochemical staining was performed to investigate major histocompatibility complex class I antigens of the transplanted tracheal segment. RESULTS: Two months after tracheal transplantation, 6 surviving ACI rats were killed. Histologically, the epithelium and tracheal cartilage of the transplanted cryopreserved segment displayed normal structure. Immunohistochemical staining showed that the major histocompatibility complex class I antigen of the ACI rat was expressed in the epithelium of the transplanted segment and that the class I antigen of the PVG rat was expressed in the cartilage of the transplanted segment. CONCLUSIONS: After transplantation of the cryopreserved trachea, the epithelium of the transplanted cryopreserved segment originated from the recipient epithelium whereas the cartilage retained the structure of the donor trachea. We hypothesize that transplantation of a cryopreserved trachea leads to the growth of the recipient's epithelium over the donor trachea, thereby reducing the antigenicity of the transplant.

Animals↗
PubMed1998

Frequent expression of the vascular endothelial growth factor in human non-small-cell lung cancers.

BACKGROUND: Angiogenesis is an essential factor for progression and metastases in solid tumors. It has been reported that several angiogenic factors play a role in the regulation of angiogenesis. Vascular endothelial growth factor (VEGF) is one of the most important molecules in angiogenesis. We investigated expressions of VEGF in a series of lung carcinomas with regard to clinicopathological factors. METHOD: VEGF expression was investigated by use of immunohistochemical studies and Northern blot analysis, using 155 primary and 26 metastatic lung carcinomas for the immunohistochemical studies and 10 primary and two metastatic lung carcinomas for the Northern blot analysis. All lesions were resected at surgery. RESULTS: The frequencies for positive VEGF expression were 64 of 74 (86.5%) adenocarcinomas, 38 of 67 (56.7%) squamous cell carcinomas, four of four (100%) large cell carcinomas, two of three (66.7%) adenosquamous carcinomas and one of five (20%) small-cell carcinomas, the degree of positivity generally being greater in well differentiated tumors. The majority of metastatic foci from adenocarcinomas and squamous cell carcinomas at other sites were also positive (76.5 and 66.7%, respectively). VEGF expression did not correlate with clinicopathological factors such as tumor size or pathological stage, but pathological stage I adenocarcinoma cases positive for VEGF demonstrated a shorter disease-free period when followed up for 48 months than those cases expressing VEGF negatively. CONCLUSIONS: The results indicated that VEGF expression was frequently detected in non-small-cell lung cancers and suggested that VEGF might relate to the disease-free period of the patients with early adenocarcinomas.

Adenocarcinoma↗
PubMed1998

Recovery and limitation of exercise capacity after lung resection for lung cancer.

OBJECTIVE: To assess the effects of pulmonary resection for lung cancer on postoperative recovery and limitation of exercise capacity. METHODS: Eighty-two patients (20 pneumonectomies, 62 lobectomies) underwent spirometric pulmonary tests and exercise capacity tests preoperatively, and at 3 months and more than 6 months after the operation. RESULTS: In the lobectomy group, FEV1 vital capacity (VC), and maximum oxygen consumption (VO2max) decreased significantly 3 months after the operation and improved after more than 6 months, but did not reach the preoperative values. In the pneumonectomy group, FEV1 VC, and VO2max decreased 3 months after the surgery and the values did not recover thereafter. In comparison with preoperative values, the functional percentage losses after more than 6 months for lobectomies and pneumonectomies were 11.2% and 36.1% for FEV1, 11.6% and 40.1% for VC, and 13.3% and 28.1% for VO2max, respectively. Postoperatively, maximal minute ventilation (VEmax), the maximal heart rate percentage, and maximal O2 pulse during the exercise test significantly decreased in both the lobectomy and pneumonectomy groups. Nevertheless, VEmax and O2 pulse improved more than 6 months after lobectomy compared with the value at 3 months, but not after pneumonectomy. Breathing reserve did not differ before and after surgery in the lobectomy group, although it decreased significantly after surgery in the pneumonectomy group. Subjectively, postoperative exercise after lobectomy was limited by leg discomfort (64% at more than 6 months after surgery); after pneumonectomy, exercise was limited by dyspnea (60%). CONCLUSIONS: These results suggest that there are differences between lobectomy and pneumonectomy for lung cancer in terms of recovery and limitation of exercise capacity.

Exercise Test↗
PubMed1998

[Thoracoscopic lung volume reduction surgery for emphysema].

In recent years, several institutions have been performing lung volume reduction surgery (LVRS) for emphysema, and have reported that LVRS is effective for patients with emphysema that is resistant to other forms of therapy. However, questions remain about the relationship between the extent of resection and the therapeutic benefits. In our study, 15 men with emphysema underwent thoracoscopic LVRS. We analyzed the effects of LVRS on pulmonary function, exercise performance, and subjective symptoms after both bilateral and unilateral procedures. The patients who underwent the bilateral procedure, demonstrated significantly improved pulmonary function and exercise performance and relief of their subjective symptoms. Those who underwent the unilateral procedure, demonstrated significantly improved pulmonary function and relief of their subjective symptoms. Forced expiratory volume in 1.0 second increased by an average of 51% after the bilateral procedure, and 17% after the unilateral procedure. We conclude that thoracoscopic LVRS is an effective treatment for emphysema, especially with the bilateral procedure.

Aged↗
PubMed1997

Thoracoscopic wedge resection of blebs under local anesthesia with sedation for treatment of a spontaneous pneumothorax.

We performed thoracoscopic wedge resections of blebs with a stapling device under local anesthesia with sedation in 34 consecutive patients who presented with spontaneous pneumothoraces. The indications for surgery included the absence of parietal pleural adhesions and knowledge of the precise bleb location prior to the procedure. Prior to surgery, 0.5% lidocaine was administered into the pleural space, and IV butorphanol tartrate and diazepam were administered to reduce pain and anxiety during the procedure. In our series, the thoracoscopic procedure resulted in favorable outcomes in all but two patients. There was no evidence of hemodynamic instability or arterial blood gas abnormalities encountered during the procedure. Minor postoperative complications were seen in only three patients (two with air leakage and one with transient atelectasis). One patient had a recurrence of his spontaneous pneumothorax 3 months following the procedure. Therefore, the overall success rate was 91%. We compared the results of this therapeutic modality (group 1) with those of 38 patients who underwent the procedure under general anesthesia (group 2) during the same period. The length of hospital stay was shorter in group 1 than in group 2 (4.5 +/- 1.3 vs 5.8 +/- 1.1 days; p < 0.01). Thoracoscopic wedge resections under local anesthesia are safe and offer the benefit of shorter hospital stays. We believe that this thoracoscopic technique will further simplify the surgical treatment of pneumothoraces without incremental risks.

Adolescent↗
PubMed1997

[Exercise performance and body composition in patients with chronic obstructive pulmonary disease].

Malnutritions is one cause of exercise intolerance in patients with chronic obstructive pulmonary disease. We studied the relation between exercise limitation and body composition in 20 clinically stable patients with chronic obstructive pulmonary disease. Maximal work capacity was measured during incremental exercise on a cycle ergometer, along with maximal oxygen uptake. Anaerobic threshold was determined by the V-slope method. Bone mineral content, lean mass, and fat mass were assessed by dual-energy X-ray absorptiometry. Bone mineral content and lean mass were significantly lower in moderately malnourished patients (%IBW < 80) than in well-nourished patients (%IBW > or = 90). Fat mass was significantly lower in mildly malnourished patients than in well-nourished patients. Maximal work capacity, maximal oxygen uptake, and anaerobic threshold correlated significantly with lean mass, but not with fat mass. These data suggest that lean mass is one determinant of exercise capacity in patients with chronic obstructive pulmonary disease.

Aged↗
PubMed1997

[Clipping of the thoracic duct with video-assisted thoracic surgery in the treatment of chylothorax after pulmonary resection].

We describe a procedure for video-assisted thoracoscopic clipping of the thoracic duct to treat postoperative chylothorax. This technique was successfully performed on a 62-year-old man who developed chylothorax following right lower lobectomy and partial resection of the 11th and 12th vertebral bodies for squamous cell lung cancer. Because conservative therapy for 7 days failed to reduce the amount of pleural effusion, we performed thoracoscopic examination of the thoracic duct and found a site leaking chylous fluid. The thoracic duct was successfully and easily clipped resulting in complete elimination of the effusion in 2 days. Generally, chylothorax complicating pulmonary resection has been managed by medical treatment first, followed by surgical intervention in case that fail to respond to initial therapy. The newly designed video-assisted thoracic surgery procedure reduces the trauma, shortens the drainage period and hospital stay, and provides better exposure of the thoracic duct. We believe that this procedure can be carried out shortly after the occurrence of chylothorax.

Chylothorax↗
PubMed1996

In vitro study of ablated lung tissue in Nd:YAG laser irradiation.

BACKGROUND: Neodymium:yttrium-aluminum garnet lasers are used to reduce lung volume. An assessment of the relationship between the histologic and gross findings in the lung irradiated by a laser would be helpful in laser-assisted pneumoplastic procedures. METHODS: In vitro lung lobes surgically resected for pulmonary carcinomas were irradiated with a neodymium:yttrium-aluminum garnet laser at three energy levels in three modes: contact rubbing, contact pointing, and noncontact. Pleural degeneration in 216 samples from 24 lobes was classified as coagulative, amorphous, or destructive. At all energy levels, the laser was applied for 1.5 seconds. RESULTS: Noncontact mode at 7.5 W or 15 W and contact rubbing at 5 W caused coagulative or amorphous degeneration but no destructive degeneration. The energy level correlated with the color of the degenerated pleura. The incidence of destructive pleural degeneration, which led to air leaks as revealed by an air inflation test, was 0% in pink and white samples, 59% in brown samples, and 100% in black samples (p < 0.0001, white versus brown samples). CONCLUSIONS: In neodymium:yttrium-aluminum garnet laser ablation of lung tissue, the color of the degenerated pleura correlates with the intensity of the applied laser energy and the degree of pleural degeneration.

Aged↗
PubMed1996

In vitro comparison between Argon Beam Coagulator and Nd:YAG laser in lung contraction therapy.

BACKGROUND: The Argon Beam Coagulator (ABC) and neodymium:yttrium-aluminum garnet (Nd:YAG) laser are used for lung tissue contraction. Assessing the damage of treated lung tissue is helpful in choosing devices for pulmonary volume reduction by pneumoplastic procedures. METHODS: We assessed the damage of in vitro lung lobes resected at operation for pulmonary carcinoma. Samples were irradiated with noncontact Nd:YAG laser and ABC. One hundred forty-four samples obtained from 24 lobes were examined by light microscopy. The lung tissue showing destructive degeneration at the pleura and slight coagulation at the residual parenchyma was defined as showing "air leak pattern" based on a previously reported experiment of the air inflation test. RESULTS: At the power of clinical use (Nd:YAG, 15 W; ABC, 80 W), most of the visceral pleura treated with the Nd:YAG laser was classified as presenting amorphous degeneration, and that treated with ABC showed destructive degeneration. Air leak pattern occurred in all samples treated with ABC. At the power of 40 W, ten (42%) of 24 visceral pleuras irradiated with the Nd:YAG laser were classified as presenting destructive degeneration, and of those irradiated with the ABC, 18 (75%) showed destructive degeneration (p < 0.05). Air leak patterns were found in 3 (13%) of the samples treated with the Nd:YAG laser and in 16 (63%) of those treated with the ABC (p < 0.05). CONCLUSIONS: The ABC had more potential to damage the pleura and less potential to produce underlying parenchymal coagulation in the lung tissue than did the Nd:YAG laser. This information may be useful in the selection of devices for pulmonary volume reduction by pneumoplastic procedures.

Aged↗
PubMed1996

[A case of mucoepidermoid carcinoma of the thymus].

A 19-year-old man was admitted to our hospital with anterior mediastinal cystic tumor. Subtotal thymectomy with the tumor was performed. The tumor was localized inside the thymus without outer infiltration. It weighed 145 g and measured 9 x 8 x 5 cm. The cut surface was cystic and spongy, partially with a solid focus. Pathological findings of the solid area was compatible with mucoepidermoid carcinoma of the thymus. The histogenesis of mucoepidermoid carcinoma of the thymus was discussed.

Adult↗
PubMed1996

Role of protein phosphatase in malignant osteogenic and soft tissue tumors.

The expression of the three catalytic subunits of protein phosphatase (PP) type 1 and 2A, PP1 alpha, PP1 gamma 1, and PP2AC, was examined in osteogenic tumors and soft tissue tumors by immunohistochemical analysis. The percentage of cells stained positively with antiserum against PP1 catalytic subunit isoform PP1 gamma 1, was significantly higher in malignant osteogenic tumors (chondrosarcoma, osteosarcoma, and Ewing's sarcoma) and in malignant soft tissue tumors (liposarcoma and malignant fibrous histiocytoma [M.F.H.]) than in benign tumors (osteochondroma, osteoblastoma, ossifying fibroma, enchondroma and lipoma). Furthermore, the malignant tumor lesions showed a markedly high number of cells in the S-phase fraction of the cell cycle, as compared to benign tumors. These results suggest that PP1 gamma 1 is involved in the accelerated growth of malignant tumor cells.

Bone Neoplasms↗