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Biomedical subjects

Yoshitaka Yamazaki

Publications and source records attributed to Yoshitaka Yamazaki.

At least 19 recordsLinked to original sources
PubMed2006

Angiosarcoma with sacral origin metastasizing to the lung.

A 73-year-old man with fever, lumbago and hemosputum showed ground-glass opacity around multiple lung nodules on chest computed tomography. Examination of the man revealed anemia. Specimens obtained by video-assisted thoracic surgery revealed angiosarcoma, but the primary site of angiosarcoma could not be detected before autopsy. Angiosarcoma is a rare malignant neoplasm with rapid proliferation and they can arise at any region of the body. It can originate in the skin, soft tissue, liver or heart. Their multicentric and local recurrence easily leads us to misdiagnosis, and we have struggled to reach diagnosis and its origin. Angiosarcoma should be included in the different diagnosis of diffuse pulmonary hemorrhage with multiple lung nodules.

Aged↗
PubMed2006

Hypersensitivity pneumonitis induced by spores of Penicillium citrinum in a worker cultivating Enoki mushroom.

A 47-year-old Japanese woman was admitted to our hospital with a 2-week history of dry cough and shortness of breath. She had been engaged in Enoki mushroom production for 22 years. Chest X-ray and chest computed tomography (CT) scan showed bilateral fine-nodular shadows and ground glass opacity. Bronchoalveolar lavage fluid demonstrated an increase of total cell counts with predominant lymphocytosis. Pathological specimens obtained by video-assisted thoracoscopic surgery revealed alveolitis and noncaseating granuloma with giant cells. Lymphocyte stimulation test showed positive responses with Enoki mushroom, culture medium, and Penicillium citrinum. On double immunodiffusion test, a precipitation line was observed between patient's serum and Penicillium citrinum antigen. She was found to have hypersensitivity pneumonitis caused by Penicillium citrinum. This is the first report of mushroom worker's lung caused by Penicillium citrinum.

Agaricales↗
PubMed2006

Usefulness of preoperative endobronchial ultrasound for airway invasion around the trachea: esophageal cancer and thyroid cancer.

BACKGROUND: It is important to confirm preoperative tracheobronchial invasion to enable the selection of the most appropriate treatment. OBJECTIVE: This study was performed to compare the usefulness of computed tomography (CT), magnetic resonance image (MRI) and bronchoscopy by endobronchial ultrasonography (EBUS) for the assessment of invasion of thyroid or esophageal cancer in cases with suspected tracheobronchial invasion. METHODS: In cases with suspected contact between the tumor and tracheobronchial wall, CT, MRI and EBUS indicated deformity of the tracheobronchial wall due to the adjacent mass. The final diagnosis was based on surgical and histological results, and/or clinical follow-up. RESULTS: Fifty-four patients were included in this study. Based on the findings of CT, MRI and EBUS, invasion was suspected in 29, 28 and 25 patients, respectively. Seventeen patients did not undergo surgery based on the results of CT, MRI and bronchoscopy with EBUS. Final diagnosis was intact trachea or bronchial adventitia in 26 patients and invasion in 28 patients. The sensitivity and specificity of CT, MRI and EBUS for invasion were 59 and 56, 75 and 73, and 92 and 83%, respectively. The accuracy of EBUS was significantly greater than that of CT in the present study (p = 0.0011). The accuracy of EBUS was significantly different from that of CT and MRI in the surgically treated patients (p = 0.005 and p = 0.032, respectively). CONCLUSION: EBUS is the most useful technique for determining the depth and extent of tumor invasion into the airway wall. The combination of MRI and EBUS will contribute to surgical planning in patients with esophageal and thyroid cancer.

Adult↗
PubMed2006

Clinical differences in the Global Initiative for Chronic Obstructive Lung Disease Stage 0.

This study was to examine the clinical differences between Stage 0 and normal subjects, using low-dose chest computed tomography (CT) and pulmonary function tests. Enrolled subjects performed as a health check for lung cancer screening including low-dose CT and pulmonary function tests. Subjects were divided into Stage 0, chronic obstructive pulmonary disease according to pulmonary function tests, and normal subjects. The severity of emphysema (visual score) was calculated on three low-dose CT slices. Low-dose CT and pulmonary function tests were performed in 1359 men and 888 women. The numbers and percentages of men and women smokers were 1076 (79.2%), and 107 (12.0%), respectively. A total of 722 individuals had one or more respiratory symptoms, such as cough (69.8%), sputum (75.8%), or shortness of breathing (0.83%). Of the 722 subjects, 71 (9.8%) individuals satisfied the criteria of chronic respiratory symptoms. Among the normal subjects, smoking caused differences in airflow limitation as a result of pulmonary function tests. The proportion of smokers and the visual score were significantly higher in Stage 0 than those in the normal subjects. The percentages of the maximal mid-expiratory flow (%MMF) and of the peak expiratory flow rate were significantly lower in Stage 0 than in the normal subjects. %MMF and the proportion of visual score were significantly lower in the smoking Stage 0 than in the nonsmoking Stage 0 subjects. Smoking would indicate early signs of emphysematous change between Stage 0 and normal subjects in comparison of pulmonary function tests and visual score of low-dose CT.

Female↗
PubMed2006

Therapeutic effects for hypersensitivity pneumonitis induced by Japanese mushroom (Bunashimeji).

BACKGROUND: Bunashimeji-related hypersensitivity pneumonitis is found among workers who cultivate the mushroom in indoor facilities. An evaluation of protective measures was initiated using the outcomes of clinical, immunological, and radiological findings. METHODS: Twenty-two patients presented with symptoms of HP; all were employed cultivating Bunashimeji mushrooms in indoor facilities. After hospitalization, 6 of 22 patients quit their job to avoid exposure to spores (Avoidance group). Sixteen patients continued to work used a mask for 3 months, and were then divided into two subgroups: Mask alone (seven patients) and mask plus oral prednisolone (Mask + PSL) (nine patients). The erythrocyte sedimentation rate (ESR), serum Krebs von der Lungen-6 (KL-6), surfactant protein-D (SP-D), lymphocyte stimulation test (LST), ground-glass scores in chest high-resolution computed tomography (HRCT), and bronchoalveolar lavage (BAL) were assessed before and after treatment. RESULTS: Complete avoidance resulted in a significant decrease in LST. There was a significant decrease after PSL treatment in serum KL-6, SP-D, and total cell counts in the BAL fluid in the Mask + PSL group. In the Mask alone group, serum KL-6, SP-D, ground-glass scores in chest HRCT and total cell counts in BAL fluid showed high levels compared with the other two groups. CONCLUSIONS: Complete cessation was the best treatment for hypersensitivity pneumonitis. The use of a mask was ineffective for patients with a high serum KL-6 and SP-D concentration and severe ground-glass opacity on chest HRCT. Initial treatment with PSL is recommended for these patients with high levels of total cell counts in BAL fluid.

Agaricales↗
PubMed2006

Endobronchial argon plasma coagulation for the management of post-intubation tracheal stenosis.

Post-intubation tracheal stenosis is usually caused by pressure necrosis at the cuff. Despite the fact that this phenomenon is well known and both large volume and low pressure cuffs have been developed, this lesion nevertheless continues to occur. Although the best results for tracheal reconstruction are obtained by an experienced surgeon, not all patients are able to undergo this operation for either medical or personal reasons. Argon plasma coagulation (APC) using flexible bronchoscopy has been successfully employed in the treatment of post-intubation tracheal stenosis in two of the surgery-refused and inoperable patients. The patients immediately experienced a relief of symptoms after APC. APC was thus performed 3-4 times every 1-2 weeks for each patient. In addition, there were no complications related to this procedure. The number of published clinical reports describing APC in benign airway stenosis are increasing. APC has also been reported to have several advantages over other interventional endobronchial techniques in the management of tracheo-bronchial stenosis. We report two patients, and to our knowledge this is the first description of APC being used in the treatment of endobronchial dilatation for post-intubation tracheal stenosis.

Aged↗
PubMed2006

The ability to form biofilm influences Mycobacterium avium invasion and translocation of bronchial epithelial cells.

Organisms of the Mycobacterium avium complex (MAC) are widely distributed in the environment, form biofilms in water pipes and potable water tanks, and cause chronic lung infections in patients with chronic obstructive pulmonary disease and cystic fibrosis. Pathological studies in patients with pulmonary MAC infection revealed granulomatous inflammation around bronchi and bronchioles. BEAS-2B human bronchial epithelial cell line was used to study MAC invasion. MAC strain A5 entered polarized BEAS-2B cells with an efficiency of 0.1 +/- 0.03% in 2 h and 11.3 +/- 4.0% in 24 h. In contrast, biofilm-deficient transposon mutants 5G4, 6H9 and 9B5 showed impaired invasion. Bacteria exposed to BEAS-2B cells for 24 h had greater ability to invade BEAS-2B cells compared with bacteria incubated in broth. M. avium had no impact on the monolayer transmembrane resistance. Scanning electron microscopy showed that MAC A5 forms aggregates on the surface of BEAS-2B cell monolayers, and transmission electron microscopy evidenced MAC within vacuoles in BEAS-2B cells. Cells infected with the 5G4 mutant, however, showed significantly fewer bacteria and no aggregates on the cell surface. Mutants had impaired ability to cause infection in mice, as well. The ability to form biofilm appeared to be associated with the invasiveness of MAC A5.

Animals↗
PubMed2006

Mycobacterium avium genes associated with the ability to form a biofilm.

Mycobacterium avium is widely distributed in the environment, and it is chiefly found in water and soil. M. avium, as well as Mycobacterium smegmatis, has been recognized to produce a biofilm or biofilm-like structure. We screened an M. avium green fluorescent protein (GFP) promoter library in M. smegmatis for genes involved in biofilm formation on polyvinyl chloride (PVC) plates. Clones associated with increased GFP expression > or =2.0-fold over the baseline were sequenced. Seventeen genes, most encoding proteins of the tricarboxylic acid (TCA) cycle and GDP-mannose and fatty acid biosynthesis, were identified. Their regulation in M. avium was confirmed by examining the expression of a set of genes by real-time PCR after incubation on PVC plates. In addition, screening of 2,000 clones of a transposon mutant bank constructed using M. avium strain A5, a mycobacterial strain with the ability to produce large amounts of biofilm, revealed four mutants with an impaired ability to form biofilm. Genes interrupted by transposons were homologues of M. tuberculosis 6-oxodehydrogenase (sucA), enzymes of the TCA cycle, protein synthetase (pstB), enzymes of glycopeptidolipid (GPL) synthesis, and Rv1565c (a hypothetical membrane protein). In conclusion, it appears that GPL biosynthesis, including the GDP-mannose biosynthesis pathway, is the most important pathway involved in the production of M. avium biofilm.

Bacterial Proteins↗
PubMed2006

The ability of Mycobacterium avium subsp. paratuberculosis to enter bovine epithelial cells is influenced by preexposure to a hyperosmolar environment and intracellular passage in bovine mammary epithelial cells.

Mycobacterium avium subsp. paratuberculosis is the cause of Johne's disease in cattle and other ruminants. M. avium subsp. paratuberculosis infection of the bovine host is not well understood; however, it is assumed that crossing the bovine intestinal mucosa is important in order for M. avium subsp. paratuberculosis to establish infection. To examine the ability of M. avium subsp. paratuberculosis to infect bovine epithelial cells in vitro, Madin-Darby bovine kidney (MDBK) epithelial cells were exposed to M. avium subsp. paratuberculosis. It was observed that bacteria can establish infection and replicate within MDBK cells. M. avium subsp. paratuberculosis also has been reported to infect mammary tissue and milk, and we showed that M. avium subsp. paratuberculosis infects bovine mammary epithelial cells (MAC-T cell line). Using polarized MAC-T cell monolayers, it was also determined that M. avium subsp. paratuberculosis crosses apical and basolateral surfaces with approximately the same degree of efficiency. Because M. avium subsp. paratuberculosis can be delivered to the naïve host by milk, it was investigated whether incubation of M. avium subsp. paratuberculosis with milk has an effect on invasion of MDBK cells. M. avium subsp. paratuberculosis exposed to milk entered epithelial cells with greater efficiency than M. avium subsp. paratuberculosis exposed to broth medium or water (P < 0.01). Growth of M. avium subsp. paratuberculosis within MAC-T cells also resulted in augmented ability to subsequently infect bovine MDBK cells (P < 0.001). Microarray analysis of intracellular M. avium subsp. paratuberculosis RNA indicates the increased transcription of genes which might be associated with an invasive phenotype.

Animals↗
PubMed2004

Effects of macrolides and ketolides on mycobacterial infections.

New macrolides, such as clarithromycin and azithromycin, are active agents to Mycobacterium avium complex (MAC). Both clarithromycin and azithromycin are well-known for the ability to improve the prognosis of AIDS patients with disseminated MAC infection. However, the administration of monotherapy with a macrolide is usually associated with the emergence of drug resistance after a few months of use. Therefore, the recommended treatment for MAC infection involved the use of at least two antibiotics, which includes a macrolide in combination with rifabutin, moxifloxacin and/or ethambutol. When used as prophylactic therapy in AIDS patients, azithromycin is more convenient (1200 mg, once a week) than clarithromycin (500 mg, twice a day). Ketolides are a semi-synthetic derivative of erythromycin A, which differs from erythromycin A by substitution of a 3-keto group for L-cladinose. Telithromycin has a carbamate group linked to an imidazolium and pyridium nucleus at C11-C12. In mice model, both telithromycin and ABT-733 were active in vivo against MAC.

Animals↗
PubMed2003

[A case of bronchial arterial aneurysm associated with recurrent massive hemoptysis].

A 69-year-old man was admitted to our hospital because of massive hemoptysis. Bronchial arteriography showed no abnormal findings. Bronchoscopic findings revealed a small, reddish elevated lesion on the posterior surface of the left upper lobe bronchus. Since the patient developed massive hemoptysis four times in a month, he underwent ligation and transection of the left bronchial artery, and bronchoplasty. Histopathologically, the resected tissue showed a bronchial arterial aneurysm without any inflammatory changes. We concluded that the aneurysm had developed in a malformed vessel.

Aged↗
PubMed2002

Alveolar shrinkage in bronchioloalveolar carcinoma without central fibrosis.

Preservation of alveolar architecture in small bronchioloalveolar carcinoma (BAC) is one of the most important factors for predicting their prognosis, alveolar shrinkage in BAC, however, has not been studied well. In ten cases of pure BAC without collapse or central fibrosis, we measured two two-dimensional (2D) parameters; side-length of the alveoli facing alveolar ducts and circumference of the alveoli forming complete circles. And we also examined three-dimensionally (3D) elastic fibers and myofibroblasts in the thick sections. In BAC, 2D parameters showed alveolar shrinkage. The elastic fibers forming the alveolar framework, including the alveolar orifice, were 3D sinuous and bent in BAC, and suggested that alveolar shrinkage cased by folding of the alveolar wall. Myofibroblasts lay transversely and longitudinally in the interstitium in BAC, intertwined with the elastic fibers. Proliferation of myofibroblasts may be of importance in alveolar wall-folding and alveolar shrinkage in BAC.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2002

Pseudomembranous tracheobronchitis caused by methicillin-resistant Staphylococcus aureus.

We report a case of severe tracheobronchitis caused by methicillin-resistant Staphylococcus aureus in a man exhibiting symptoms of upper airway obstruction after infection with influenza. Bronchoscopy revealed diffuse pseudomembrane formation throughout the trachea and bilateral bronchi, which were nearly obstructed. In this case, it was helpful to perform bronchoscopy, protected brushing and tracheotomy immediately in order to avoid choking.

Aged↗
PubMed2002

Chemotherapy for advanced thymic carcinoma: clinical response to cisplatin, doxorubicin, vincristine, and cyclophosphamide (ADOC chemotherapy).

The role of systemic chemotherapy and optimal regimen in thymic carcinoma remains uncertain. We evaluated the clinical responsiveness of ADOC (cisplatin, doxorubicin, vincristine, and cyclophosphamide) chemotherapy for advanced thymic carcinoma that have distant metastatic or unresectable lesions. From 1996 to 2000, we treated eight cases of thymic carcinoma. According to the classification by Masaoka et al., the clinical stage in one case was IVa, whereas the others were IVb. Histologic subtypes were as follows: four cases were squamous cell carcinoma, two cases were undifferentiated, and two were small-cell carcinoma. All patients received 50 mg/m2 of cisplatin and 40 mg/m2 of doxorubicin intravenously on day 1, 0.6 mg/m2 of vincristine intravenously on day 3, and 700 mg/m2 of cyclophosphamide intravenously on day 4, ADOC regimen, respectively, at 3- to 4-week intervals. Six patients obtained a partial response after ADOC chemotherapy and the overall clinical response rate was 75%. There were no life-threatening side effects noted. Cisplatin plus VP-16 chemotherapy (PVP) was performed in three cases before the ADOC regimen, but PVP chemotherapy did not show beneficial effects in two patients. Median survival time was 19 months. ADOC chemotherapy appears to have significant activity against thymic carcinoma.

Adult↗
PubMed2002

Lung tissue distribution after intravenous administration of grepafloxacin: comparative study with levofloxacin.

The aim of the present study is to study the pharmacokinetics in plasma, lung lymph and bronchial washing fluid after intravenous infusion of grepafloxacin (GPFX), in comparison with those of levofloxacin (LVFX). Four conscious sheep with chronically instrumented lung lymph fistulas and tracheotomy were prepared. GPFX and LVFX concentrations in plasma and lung lymph after intravenous infusion of the drugs (10 mg/kg) for over 10 min were measured. In addition serial bronchial washing with 50 mL normal saline was performed to obtain epithelial lining fluid (ELF) at 2, 4, 6, 8, 12, 24 h after the intravenous administration. The time courses of lung lymph concentration were almost identical to those of the concomitant levels of both GPFX and LVFX in plasma, suggesting that both GPFX and LVFX could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. However, GPFX concentrations of ELF were significantly higher than LVFX concentrations over time after the administration. In addition, intracellular concentrations in ELF of GPFX were also extremely high compared with those of LVFX. These results demonstrated that penetration of GPFX in bronchial wall, bronchial epithelium and/or phagocytic cells was superior to that of LVFX. These observations suggest that the pharmacokinetic characteristics of GPFX in the lung may provide a new insight into the strategy for clinical treatment of various pulmonary infections, especially cytotropic bacterial infections.

Animals↗
PubMed2002

Effects of serum on hepatocyte growth factor secretion and activation by periodontal ligament and gingival fibroblasts.

BACKGROUND: Hepatocyte growth factor (HGF)/scatter factor is a paracrine growth factor secreted by mesenchymal cells, which exerts an effect on a variety of epithelial cell types. Our recent study revealed that periodontal ligament fibroblasts (PLF) and gingival fibroblasts (GF) cultured in the presence of serum which contains various stimulants produced HGF or HGF-like factor, a predominant chemoattractant for gingival epithelial cells, and suggested that it could be involved in epithelial down-growth in periodontitis. METHODS: To clarify whether serum in medium stimulates PLF and GF to synthesize or activate HGF, the effect of fetal bovine serum (FBS) on HGF production was determined by enzyme-linked immunoabsorbent assay (ELISA), and its chemotactic activity for gingival epithelial cells was examined by modified Boyden chamber assay. RESULTS: One to 10% FBS in the culture medium stimulated HGF secretion in a dose-dependent manner and the chemotactic activity was decreased by treatment with anti-hHGF neutralizing antibody. Furthermore, fibroblast-conditioned medium incubated with FBS and aprotinin reduced its chemotactic activity. Interestingly, serum-free culture of PLF and GF produced potent chemoattractants for gingival epithelial cells other than HGF. CONCLUSIONS: These results show that FBS stimulates both HGF secretion and activation by PLF and GF.

Animals↗