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Biomedical subjects

Kenji Nakamura

Publications and source records attributed to Kenji Nakamura.

At least 55 records · Page 3Linked to original sources
PubMed2004

Assessment of cerebral microembolism during percutaneous radiofrequency ablation of lung tumors using diffusion-weighted imaging.

OBJECTIVE: It is well known that radiofrequency ablation generates microbubbles in the liver. We hypothesized that microbubbles generated during percutaneous radiofrequency ablation of lung tumors flow into the pulmonary veins and are distributed to the systemic arteries, as with radiofrequency ablation of liver tumors. To assess the risk of cerebral infarction during radiofrequency ablation of lung tumors, we performed diffusion-weighted imaging and, if possible, monitored microemboli in the carotid artery during radiofrequency ablation. SUBJECTS AND METHODS: We prospectively studied 20 patients (19 men and one woman) who underwent radiofrequency ablation of lung tumors. Pre- and postoperative MRI examinations were performed in all 20 patients, and during 17 radiofrequency ablation sessions, sonography was used to monitor whether microemboli were generated. RESULTS: Radiofrequency ablation was technically feasible for the treatment of selected pulmonary tumors. Microemboli, which were believed to represent microbubbles, were seen on sonography during three of the 17 radiofrequency ablation sessions. They were rarely observed when a lung tumor was small, the treatment session was brief, and the radiofrequency emission power was low. No new area of abnormal intensity was seen on postoperative MRI in all 20 patients. Although the microemboli were observed, MRI could not confirm infarction. CONCLUSION: We concluded that cerebral infarction as a result of microbubbles generated during radiofrequency ablation of lung tumors has a low possibility of becoming a clinical problem.

Aged↗
PubMed2004

[Sjögren's syndrome with solitary nodular pulmonary amyloidosis].

We describe a case of limited pulmonary amyloidosis with Sjögren syndrome. A 58-yr-old woman was referred to our hospital because of an abnormal chest radiograph (solitary small nodule) that was examined to investigate the cause of a persistent cough. A chest CT revealed a solitary small nodule in the left lower lung field. The specimens obtained by thoracoscopic surgery showed AL (kappa) amyloid deposits with lymphoplasmacytic infiltrate. Immunofixation of the serum and concentrated urine failed to demonstrate monoclonal immunoglobulins, and no amyloid deposits in the stomach were detected. She was subsequently diagnosed as having primary Sjögren's syndrome. Nodular pulmonary amyloidosis with Sjögren syndrome is very rare condition, and most cases present multiple nodules. As far as is known, this is the first report of a solitary nodule in pulmonary amyloidosis with Sjögren syndrome.

Amyloidosis↗
PubMed2004

[Pathogenesis and treatment of chronic empyema].

In chronic empyema (CE), thickened pleura, collapsed chest wall, and the accumulation of purulent fluid in the thoracic cavity are typical findings. Patients complaints of symptoms with bronchopleural fistula (BPF). On the other hand, there is another type of CE in which the pleural space expands progressively to shift the neighboring lungs, mediastinum, and diaphragm. This type of CE is considered to be chronic expanding hematoma (Reid et al.) occurring in the thoracic cavity. In the empyemic cavity, mycobacterial infection is found approximately in 20-30% of cases, pyogenic bacillus or fungus in about 40%, but the cavity is aseptic in other 30-40%. Although the fundamental treatment procedures include decortication and pleuropneumonectomy, the method of muscle or omental plombage to manage dead space or BPF are far superior functionally in intractable CE. Recently, the methods of plastic and reconstructive surgery have been used to utilize the muscle or omentum more effectively. The classic thoracoplasty procedure should not be undertaken unnecessarily to avoid additional deterioration of respiratory function. Additionally, it should be remembered that malignant lymphoma occurs frequently in the empyemic chest wall.

Chronic Disease↗
PubMed2004

[Development of the reimbursement system based on DPC].

In the health insurance system of Japan, a fee-for-service system has been applied to individual treatment services, but this fee system involves a structural problem of causing increases in examinations and drug administration. Various attempts have been made to solve this structural problem in several treatment fields, in which a flat payment system can be introduced with the fee for-service system as the basis. The diagnosis procedure combination (DPC) system introduced in April 2003, which is a flat payment system using a diagnosis classification, is the first large scale revision of the medical fee system of Japan. This diagnosis classification is considered to be effective for simplifying the medical fee system, within the framework of EBM, and for providing patients with information. However, since there are also structural problems in the flat payment system, such as examination and treatment of low quality, selection of patients, and upcoding, its introduction should be performed with sufficient caution. We will make more efforts to establish a better medical fee system by evaluating these problems.

Diagnosis-Related Groups↗
PubMed2003

Disruption of protein kinase Ceta results in impairment of wound healing and enhancement of tumor formation in mouse skin carcinogenesis.

We have generated a mouse strain lacking protein kinase C (PKC) eta to evaluate its significance in epithelial organization and tumor formation. The PKCeta-deficient mice exhibited increased susceptibility to tumor formation in two-stage skin carcinogenesis by single application of 7,12-dimethylbenz(a)anthracene (DMBA) for tumor initiation and repeated applications of 12-O-tetradecanoylphorbol-13-acetate (TPA) for tumor promotion. The tumor formation was not enhanced by DMBA or TPA treatment alone, suggesting that PKCeta suppresses tumor promotion. Epidermal hyperplasia induced by topical TPA treatment was prolonged in the mutant mice. The enhanced tumor formation may be closely associated with the prolonged hyperplasia induced by topical TPA treatment. In the mutant mice, after inflicting injury by punch biopsy, wound healing on the dorsal skin, particularly reepithelialization, was significantly delayed and impaired in structure. Impairment of epithelial regeneration in wound healing indicates a possibility that PKCeta plays a role in maintenance of epithelial architecture. Homeostasis in epithelial tissues mediated by PKCeta is important for tumor formation in vivo. We propose that PKCeta is involved in tumor formation modulated by regulation of proliferation and remodeling of epithelial cells in vivo.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Expression of cyclooxygenase-1 and -2 in human breast cancer.

PURPOSE: We investigated the expression of cyclooxygenase (Cox-1 and Cox-2) in mammary tissues from patients with breast cancer. METHODS: We used reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: The cancer cells showed very weak expression of Cox-1, but strong expression of immunoreactive Cox-2. In contrast, immunoreactive Cox-2 was very weak in all of the benign mammary tumors examined, including fibroadenoma (FA) and mastopathy (MP). Immunoreactive Cox-1 was also very weak in these benign tumors. The extent and intensity of immunoreactive Cox-2 polypeptides was significantly greater in the cancer cells than in the FA cells or MP cells. RT-PCR analysis showed enhanced expression of Cox-2, but not Cox-1 in breast cancer tissue, and faint expression of Cox-2 in benign tissue. CONCLUSIONS: These results demonstrated that human breast cancer cells generated Cox-2, indicating that Cox-2 might play an important role in the proliferation of breast cancer cells.

Adult↗
PubMed2003

Pulmonary embolism in a living-related kidney transplantation donor.

Living-related renal transplantation is the optimal therapy for patients with end-stage renal disease (ESRD). Normally, complications are rare in living-related donor nephrectomy. However, we experienced a case of pulmonary embolism (PE). The incidence of PE in living donor nephrectomy is rare, but the total incidence of PE in surgical operations has recently increased. The patient in the case reported here was diagnosed relatively early and recovered with appropriate treatment. It is very important for surgeons to realize that serious complications such as PE can develop in any case of living donor nephrectomy.

Aged↗
PubMed2003

Simultaneous determination of percentage of Lens culinaris agglutinin-reactive alpha-fetoprotein and alpha-fetoprotein concentration using the LiBASys clinical auto-analyzer.

BACKGROUND: Lens culinaris agglutinin (LCA)-reactive alpha-fetoprotein (AFP-L3) percentage of total AFP concentration [(AFP-L3/total AFP)x100] has been used as an effective marker for earlier diagnosis, for assessment of therapeutic effects and for predicting the prognosis of hepatocellular carcinoma (HCC). METHODS: A new clinical automatic analyzer, the "LiBASys", and an assay kit for the simultaneous determination of AFP-L3 percentage and concentration of AFP in human serum were developed. LiBASys performed automatic re-measurement and also met stat samples. Both AFP-L3 percentage and AFP concentration were calculated simultaneously and printed out continuously every 3.4 min per test. RESULTS: A linear dose-response relationship was observed up to 1000 ng/ml AFP concentration. The detection limit and functional sensitivity of LCA-nonreactive AFP (AFP-L1) and AFP-L3 concentrations were 0.4 and 0.8 ng/ml, and 0.4 and 1.0 ng/ml, respectively. Interassay CVs of AFP-L3 percentage and AFP concentration ranged from 2.8% to 13.4% and 2.6% to 4.6%, respectively. Assay results exhibited good correlations with those of commercially available lectin-affinity electrophoresis (r=0.984) for AFP-L3 percentage and with the RIA method (r=0.999) for AFP concentration. CONCLUSIONS: This method simultaneously yields both qualitative and quantitative results for AFP-L3 percentage and AFP concentration.

Adult↗
PubMed2003

Clinicopathological investigation of 20 cases of primary tracheal cancer.

OBJECTIVE: Primary tracheal cancer is considered to be relatively rare. Its epidemiology, therapeutic strategy and prognosis are not well understood. METHODS: We retrospectively investigated the clinicopathological aspects of 20 patients with primary tracheal cancer. RESULTS: Patients included 11 men and nine women with a mean age of 57.3 years. There were 12 squamous cell carcinomas and eight adenoid cystic carcinomas. Four patients received only palliative therapy. Sixteen patients underwent surgical treatment such as segmental tracheal, laryngotracheal, or carinal resection. One patient with squamous cell carcinoma died of postoperative mediastinitis. Although resected specimens from five patients had tumor positive margins, only one of those patients died after local recurrence and only three patients had postoperative treatment. The 5-year survival rate for patients who underwent surgery was 72.3%. CONCLUSIONS: Surgical treatment is the first choice therapeutic modality for primary tracheal cancer in consideration of its prognosis. While performing the operation, safety of the anastomosis should take precedence over completeness of resection.

Adult↗
PubMed2003

Lamivudine therapy for hepatitis B virus reactivation in a patient receiving intra-arterial chemotherapy for advanced hepatocellular carcinoma.

We describe a case of hepatitis B virus (HBV) reactivation that responded to lamivudine therapy in a 58-year-old man with advanced hepatocellular carcinoma (HCC). After seroconversion of hepatitis B e antigen to e antibodies by interferon therapy, the patient was found to have HCC with a portal tumor thrombus. A transarterial port was placed in the right femoral artery to permit infusion of epirubicin and cisplatin. After 3 months of arterial chemotherapy, the serum alpha-fetoprotein level had decreased and tumor staining diminished. Laboratory examinations suggested a flare-up of hepatitis B. Lamivudine was given to manage HBV reactivation. After 1 month, the serum HBV DNA level fell below the detection limit, and the alanine aminotransferase activity decreased to the normal range. With further arterial chemotherapy for HCC, no tumor staining was detected on computed tomography. Administration of lamivudine decreased serum HBV DNA levels for 7 months. Our findings suggest that HBV may be reactivated during chemotherapy for HCC, similar to other types of malignancies, and that lamivudine is effective for the management of HBV reactivation.

Journal Article↗
PubMed2003

Ciliated hepatic foregut cyst. A report of one case and a review of the literature.

We encountered a patient with a ciliated hepatic foregut cyst (CHFC), which is an uncommon cystic lesion of the liver and hard to distinguish from malignant tumor in imaging features. Cases of CHFC are very rare, five cases were reported in the 19th century and 53 cases in the 20th century. The histogenesis of CHFC is still unclear, but most authors consider that it could arise from the embryonic foregut. A few cases of CHFC mimicking neoplasm were reported. When the diagnosis of CHFC was obtained by fine needle aspiration, close follow-up is necessary in order to find early malignant change.

Journal Article↗
PubMed2003

Esophagogastric varices due to arterioportal shunt in a serous cystadenoma of the pancreas in von Hippel-Lindau disease.

Von Hippel-Lindau (VHL) disease is an autosomal dominant inherited disorder characterized by extensively vascularized tumors and cysts in specific organs. Angiogenesis is a striking future of VHL disease with its characteristic cysts and well-vascularized tumors. The hypervascular nature of VHL lesions has been linked to the overproduciton of vascular endothelial growth factor (VEGF) through increased expression of hypoxia inducible factor-1alpha (HIF-1alpha). Here we describe a rare case of VHL disease with esophageal and gastric varices due to arterioportal shunt in a serous cystadenoma of the pancreas, which, upon immunohistochemical examination, exhibited HIF-1alpha and VEGF expression. Rupture of esophageal varices was successfully treated with endoscopic injection sclerotherapy.

Angiography↗
PubMed2003

Clinicopathological evaluation of renal allografts of four patients by 20-year protocol biopsies.

Twenty-year protocol biopsies were performed in four cases of renal transplant recipients with grafts that had survived 20 years or more. All four recipients received transplants from their parents, and never had episodes of acute rejection. They were maintained with the conventional immunosuppressive protocol including azathioprine, mizoribine, and prednisolone. Three of them had past history of malignant diseases such as breast cancer and tongue cancer. In spite of fair graft function, the microscopic findings of 20-year protocol biopsy showed various degrees of histological damage; e.g. obsolescence of the glomeruli, glomerulosclerosis, arteriole wall thickening, interstitial fibrosis and tubular atrophy. Although two of the four grafts were functioning with low serum creatinine levels (1.3-1.4 mg dL-1) at 24 years and 26 years following transplantation, respectively, the function of the other two grafts had decreased more than 20 years after transplantation. In the two grafts with decreased function, glomerulosclerosis and arteriole wall thickening tended to be more severe (Banff classification of chronic allograft nephropathy [CAN] grade II and III) at the 20-year protocol biopsy compared with the two well-functioning grafts (CAN grade I and II). We conclude that the protocol biopsies even at 20 years can contribute to predict the fate of renal allografts.

Adolescent↗
PubMed2003

Renal allograft arteriovenous fistula and large pseudoaneurysm.

The patient was a 51-year-old female. Post-biopsy arteriovenous fistula (AVF) and pseudoaneurysm in a renal allograft were diagnosed 5 yr and 4 months after she received a renal transplantation. Four years after the diagnosis, interventional treatment for the AVF and pseudoaneurysm was performed because of a high risk of pseudoaneurysm rupture. Although the longitudinal diameter of the pseudoaneurysm was more than 5 cm, this AVF and pseudoaneurysm were treated successfully by a percutaneous transluminal embolization, and renal function has remained stable after embolization. A selective interventional procedure proved effective for the large pseudoaneurysm in the renal allograft. Therefore, when a transcutaneous needle biopsy of the renal allograft is performed, although there are no apparent symptoms or signs of vascular complications during the clinical course, periodical examinations such as echo-Doppler imaging should be made on the allograft.

Aneurysm, False↗
PubMed2003

Current characteristics of infective endocarditis in Japan: an analysis of 848 cases in 2000 and 2001.

The Japanese Circulation Society appointed a committee to develop guidelines for the prevention, diagnosis and management of infective endocarditis in Japan. In making such guidelines, the committee required information on the current clinical characteristics of infective endocarditis and therefore performed a nationwide questionnaire survey of cases from 2000 and 2001. In total, data were received for 848 cases from 277 of the 817 hospitals surveyed. Mean age was 55+/-18 years and most patients were aged in their 50 s or 60 s; 53.9% of the patients had infective endocarditis of unknown origin (without any prior predisposing conditions or procedures) and the second most common etiology was post dental procedures. The most common microorganism was Gram-positive cocci (345 streptococci and 221 staphylococci) and methicillin resistant Staphylococcus aureus (MRSA) was found in 7.3%. Although more than 90% of cases with Streptococcus viridans were sensitive to penicillin G, 6.6% were resistant. All MRSAs were sensitive to vancomycin. The information obtained from the survey assisted in the making of the guidelines, which should become an indispensable tool for all clinicians.

Adult↗
PubMed2003

Necrotic hepatitis due to Clostridium perfringens infection in newly hatched broiler chicks.

Multiple necrotic hepatitis lesions of 5 newly hatched broiler chicks in three flocks derived from two hatcheries were examined pathologically. The livers were brittle, and multiple yellowish or green foci were scattered on the surface and cut surface. The main histological finding was well demarcated multi-focal necrosis in the liver. Many Gram-positive large bacilli that reacted positively with polyclonal anti-Clostridium perfringens serum were observed in necrotic areas.

Animals↗
PubMed2003

Cigarette smoking-induced acute eosinophilic pneumonia showing tolerance in broncho-alveolar lavage findings.

A 19-year-old man was admitted due to acute respiratory failure. He had started cigarette smoking (CS) about three weeks prior to onset. Multiple nodular shadows and patchy infiltrations were found on chest computed tomography. His respiratory state improved promptly by intravenous methylprednisolone. He resumed CS soon after discharge without any symptoms. We suspected CS-induced acute eosinophilic pneumonia and performed broncho-alveolar lavage (BAL) about one month after onset. The proportion of eosinophils in BAL fluid was 72%. A second BAL was performed about 18 months after onset and BAL fluid included no eosinophils, despite the fact that he had continued CS.

Acute Disease↗