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Biomedical subjects

Masami Sato

Publications and source records attributed to Masami Sato.

16 recordsLinked to original sources
PubMed2003

Combination use of vitamin K(2) further increases bone volume and ameliorates extremely low turnover bone induced by bisphosphonate therapy in tail-suspension rats.

Bisphosphonate is a potent inhibitor of bone resorption, which results in the increase of bone volume. However, bisphosphonate treatment may lead to extremely low bone turnover and abnormal bone microstructure. In this study, we examined whether the combination of bisphosphonate with vitamin K(2) treatment may have beneficial effects on bone turnover and trabecular microstructure as well as on bone volume loss by using tail-suspension model rats. In these model rats, bone mineral density (BMD) decreased with histological evidence of enhanced bone resorption and suppressed bone formation. By bisphosphonate treatment, BMD was increased compared with that of tail-suspended rats. Osteoclast surface per bone surface (Oc.S/BS) and number of osteoclasts per bone perimeter (N.Oc/B.Pm) were reduced and mineral apposition rate (MAR) decreased, suggesting extreme suppression of bone turnover. However, trabecular structure examined by microfocus CT was apparently abnormal. By contrast, combination of bisphosphonate with vitamin K(2) leads to further increase of bone volume. MAR and BFR as well as Oc.S/BS and N.Oc/B.Pm were increased compared with those of the bisphosphonate-treated group. However, abnormal structure of trabeculae in secondary spongiosa was not completely ameliorated. These data suggested that concomitant use of vitamin K(2) with bisphosphonate excessively ameliorates too much suppression of bone turnover while more efficiently preventing bone volume loss.

Absorptiometry, Photon↗
PubMed2003

Endobronchial carcinoid tumor combined with pulmonary non-tuberculous mycobacterial infection: report of two cases.

We report here two cases of endobronchial carcinoid tumor complicated with pulmonary infection with non-tuberculous mycobacteria (NTM). Case 1 was an 81-year-old woman with the left lower lobe atelectasis. Bronchoscopy showed complete obstruction of the left basal bronchus by a tumor and a sleeve lower lobectomy with mediastinal lymph node dissection was performed. Pathological examination showed typical carcinoid located in the left basal bronchus and many caseous granulomas containing mycobacteria in the lung parenchyma distal to the bronchus. Bacterial examinations of sputum and gastric juice after the operation showed a growth of Mycobacterium kansasii. Case 2 was a 50-year-old woman with the atelectasis of the left upper division. Bronchoscopy showed complete obstruction of the left upper division bronchus by a tumor and a left upper lobectomy with mediastinal lymph node dissection was performed. Pathological examination showed typical carcinoid located in the left upper division bronchus and many caseous granulomas in the lung parenchyma distal to the bronchus. The Ziehl-Neelsen stain showed many mycobacteria in these granulomas and they were identified as Mycobacterium avium by PCR analysis. Although NTM are not well recognized as possible pathogens of pulmonary infection related to bronchial obstruction by endobronchial carcinoma, our experiences rouse a caution to consider NTM as potential pathogens. We also discuss the possible mechanisms responsible for the specific relationship between carcinoid tumor and TNM.

Aged↗
PubMed2003

Potentiation of proopiomelanocortin gene expression in cultured pituitary cells by benzodiazepines.

BACKGROUND: Benzodiazepines are frequently used not only as a part of general anesthesia but also for the purpose of sedation during regional anesthesia. Effects of these drugs on the hypothalamic-pituitary-adrenal axis activity have been studied, but are still controversial. It is not known whether benzodiazepines affect expression of proopiomelanocortin, precursor protein of adrenocorticotropic hormone and related peptides. METHODS: AtT20PL cell line, a clone of AtT20/D16v mouse corticotroph tumor cells stably transfected with approximately 0.7 kilobases (kb) of the rat proopiomelanocortin 5' promoter-luciferase fusion gene, was used. In the presence or absence of diazepam or midazolam, cells were stimulated by corticotropin-releasing hormone (CRH) or forskolin. Proopiomelanocortin gene expression was estimated by measurement of luciferase activity. Furthermore, to study the mechanism of benzodiazepine effects, cyclic adenosine 3',5'-monophosphate (cyclic AMP) efflux was measured by enzyme immunoassay. RESULTS: Diazepam and midazolam dose-dependently increased the proopiomelanocortin gene expression induced by CRH or forskolin. The potentiating effect was not affected by benzodiazepine receptor antagonists flumazenil and PK11195, but was abolished by a cyclic AMP-dependent protein kinase inhibitor H89. Cyclic AMP efflux induced by CRH or forskolin was also enhanced by diazepam and midazolam. In the presence of isobutylmethylxanthine, a nonspecific phosphodiesterase inhibitor, potentiation of proopiomelanocortin gene expression and enhancement of cyclic AMP efflux by benzodiazepines were not observed. CONCLUSIONS: Benzodiazepines potentiate the effect of CRH or forskolin on proopiomelanocortin gene expression. The potentiating effect is not mediated by the benzodiazepine receptors, but its mechanism probably involves inhibition of phosphodiesterase.

1-Methyl-3-isobutylxanthine↗
PubMed2002

Airflow through the auxiliary line of the laser fiber prevents ignition of intra-airway fire during endoscopic laser surgery.

BACKGROUND AND OBJECTIVES: Ignition accidents during bronchoscopic laser irradiation have occasionally been reported, but the mechanisms responsible for the ignition accidents are not fully understood. We examined causative factors including ignition site, oxygen concentration, and role of airflow through the laser fiber. STUDY DESIGN/MATERIALS AND METHODS: Porcine muscle tissue was placed in a bottle and irradiated by laser under various conditions. Also, a piece of porcine muscle was wedged in a main bronchus of the isolated porcine lungs and irradiated by laser in the same way. RESULTS: Flashing occurred on the tissue exposed to the laser, and this flashing reached the ignition when the oxygen concentration was above 30%. Increasing airflow through the laser fiber prevented the ignition even at an oxygen concentration at 100%. CONCLUSIONS: In laser irradiation, the tissue exposed to the laser can be the ignition site of fire. Increasing airflow through the laser fiber was an effective technique to prevent airway fire.

Air↗
PubMed2002

Maintenance of trabecular structure and bone volume by vitamin K(2) in mature rats with long-term tail suspension.

Bone volume loss is one of the major health problems during long-term spaceflight. We examined the effects of vitamin K(2) on bone abnormalities in tail-suspended mature male Sprague-Dawley rats (13 weeks old). In this model, increased bone resorption and sustained suppression of bone formation resulted in progressive bone loss in 4 weeks, which simulates bone changes in humans during spaceflight. A significant decrease in bone mineral density (BMD), as well as a decreased mineral apposition rate (MAR), increased number of osteoclasts per bone perimeter (N.Oc/B.Pm), and increased osteoclast surface per bone surface (Oc.S/BS) in the suspended group was effectively prevented by vitamin K(2), given orally (menatetrenone, 22 mg/kg body weight). Microfocus computed tomography (CT) and node-strut analyses revealed that the volume and structure of trabecular bone were maintained near normal by the vitamin K(2) treatment. A recent report has suggested the abnormal metabolism or action of vitamin K in a microgravity environment, and our data therefore suggest that vitamin K(2) may be useful for the prevention of bone loss and for the maintenance of normal trabecular structure during spaceflight.

Absorptiometry, Photon↗
PubMed2002

A microarray-based method for detecting methylated loci.

CpG island DNA methylation plays an important role in regulating gene expression in development and carcinogenesis. We developed a new microarray-based method called methylation amplification DNA chip (MAD) for detecting differences in methylation. In this method, only methylated CpG islands from the two samples that we wanted to compare were amplified and used for hybridization. The resource material for the microarray was derived from the methylated DNA library of the sample in which we wanted to detect hypermethylation. Choosing the methylated DNA library as the resource material of the microarray increased the percentage of DNA fragments derived from hypermethylated loci on the microarray.

Animals↗
PubMed2002

A prospective trial of systematic nodal dissection for lung cancer by video-assisted thoracic surgery: can it be perfect?

BACKGROUND: There have been no reports evaluating the completeness of systematic nodal dissection with video-assisted thoracic surgery (VATS). In order to elucidate the completeness of the dissection, we have conducted a prospective trial with patients having primary lung cancer. METHODS: Patients with clinical stage I lung cancer were the candidates for this study. Thoracotomy was performed with a small skin incision of 7 cm to 8 cm in length. Through these small wounds and two trocars, pulmonary resection was performed and then hilar and mediastinal lymph nodes were dissected. After that, a standard thoracotomy was carried out by another surgeon to complete systematic nodal dissection. RESULTS: Video-assisted thoracic surgery lobectomy with lymph node dissection was accomplished in 17 right lung cancer patients and 12 left lung cancer patients. On the right side, the average numbers of resected lymph nodes by VATS and remnant lymph nodes were 40.3 and 1.2, respectively. The average weights of dissected tissues by VATS and remnant tissues were 10.0 g and 0.2 g, respectively. On the left side, there were 37.1 and 1.2 lymph nodes and 8.3 g and 0.2 g of weight of dissected tissues. No nodal involvement was observed in the remnant lymph nodes. CONCLUSIONS: The lymph node dissection with VATS was technically feasible and the remnant ("missed" by VATS) lymph nodes and tissues were 2% to 3%, which seems acceptable for clinical stage I lung cancer.

Adult↗
PubMed2002

Roentgenographically occult bronchogenic squamous cell carcinoma involving mediastinal lymph nodes after removal of initial lesion by the diagnostic examination.

A 69-year-old male was suspected of having lung cancer by sputum cytology and diagnosed as roentgenographically occult squamous cell carcinoma (ROSCC) at the spur of left B(1+2)/B(3). However, after the first bronchoscopy, no suspicious lesion was detected by any examinations. Therefore, we considered that cancer cells had been removed completely by the initial examination, and the patient was followed up by sputum cytology, chest roentgenogram, and bronchoscopy. Sixteen months later from the initial examination, bronchoscopy was performed for follow-up. The bronchoscopic findings showed the elevation of the surface of left B(1+2) a+b, but the cytologic specimen by brushing toward B(1+2) a+b showed negative findings. However, the lesion had developed to polypoid-shaped tumor and obstructed B(1+2) a+b after the next 6 months. The tumor was diagnosed as squamous cell carcinoma, and hilar and mediastinal nodal involvement was suspected on chest computed tomography. The standard thoracotomy was performed and the pathological results showed positive for nodal involvement on hilus and mediastinum. The tumor is considered to arise from the residual cancer cells of initially detected ROSCC. In conclusion, although some ROSCCs regress by the diagnostic examinations, it is important to detect the recurrence of residual cancer cells as early as possible by intensive follow-up.

Aged↗
PubMed2002

Computed tomographic image comparison between mediastinal and lung windows provides possible prognostic information in patients with small peripheral lung adenocarcinoma.

OBJECTIVES: The purpose of this study was to determine whether the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor of small peripheral lung adenocarcinoma. METHODS: We studied the computed tomographic images of 143 patients with primary peripheral lung adenocarcinoma of 30 mm or less in maximum diameter. Two groups were categorized according to the tumor's ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image (tumor's area in the mediastinal computed tomographic image/tumor's area in lung computed tomographic image x 100%), both faint density-type (<50%) and solid-type images (>/=50%). Clinical factors and prognoses of the 2 groups were analyzed. RESULTS: There were 58 patients with the solid-type tumor image and 85 patients with the faint density-type tumor image. The number of patients with tumor size of less than 20 mm in the faint density-type tumor group (n = 30) was significantly higher than that in the solid-type tumor group (n = 8, P =.008). The 5-year survival of patients with faint density-type tumors was 74.1%, whereas that in patients with solid-type tumors was 54.2% (P =.013). Furthermore, the survival curve of patients with the solid-type computed tomographic image combined with ground-glass opacity was similar to that of patients with the faint density-type image. Multivariate analysis revealed the prognostic influence of the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image on survival (P =.029, relative risk = 0.48) and showed to be of second highest influence after the N factor. CONCLUSIONS: It is suggested that the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor in patients with small peripheral lung adenocarcinoma.

Adenocarcinoma↗
PubMed2002

Ketamine suppresses platelet aggregation possibly by suppressed inositol triphosphate formation and subsequent suppression of cytosolic calcium increase.

BACKGROUND: Ketamine has been shown to suppress platelet aggregation, but its mechanisms of action have not been defined. The purpose of the current study is to clarify the effects of ketamine on human platelet aggregation and to elucidate the underlying mechanisms of its action. METHODS: Platelet aggregation was measured using an eight-channel aggregometer, and cytosolic free calcium concentration was measured in Fura-2/AM-loaded platelets using a fluorometer. Inositol 1,4,5-triphosphate (IP3) was measured with use of a commercially available IP3 assay kit. To estimate thromboxane A2 (TXA2) receptor binding affinity and expression, Scatchard analysis was performed using [3H]S145, a specific TXA2 receptor antagonist. TXA2 agonist binding assay was also performed. The membrane-bound guanosine 5'-triphosphatase activity was determined using [gamma-32P]guanosine triphosphate by liquid scintillation analyzer. RESULTS: Ketamine (500 microm) suppressed aggregation induced by adenosine diphosphate (0.5 microm), epinephrine (1 microm), (+)-9,11-epithia-11,12-methano-TXA2 (STA2) (0.5 microm), and thrombin (0.02 U/ml) to 39.1 +/- 30.9, 46.3 +/- 4.3, -2.0 +/- 16.8, and 86.6 +/- 1.4% of zero-control, respectively. Ketamine (250 microm-1 mm) also suppressed thrombin- and STA2-induced cytosolic free calcium concentration increase dose dependently. Although ketamine (2 mm) had no effect on TXA2 receptor expression and its binding affinity, it (1 mm) suppressed intracellular peak IP3 concentrations induced by thrombin and STA2 from 6.60 +/- 1.82 and 4.39 +/- 2.41 to 2.41 +/- 0.98 and 1.90 +/- 0.86 pmol/109 platelets, respectively, and it suppressed guanosine triphosphate hydrolysis induced by thrombin (0.02 units/ml) and STA2 (0.5 microm) to 50.3 +/- 3.2 and 67.5 +/- 5.5% versus zero-control, respectively. CONCLUSION: Ketamine inhibits human platelet aggregation possibly by suppressed IP3 formation and subsequent suppression of cytosolic free calcium concentration. The site of action of ketamine is neither TXA2 nor thrombin binding sites but possibly receptor-coupled mechanisms, including G-protein.

Adenosine Diphosphate↗
PubMed2002

Production and application of new monoclonal antibodies specific for a fecal Helicobacter pylori antigen.

The aim of the present study was to establish monoclonal antibodies that could be used to produce a diagnostic test composed of one kind of monoclonal antibody recognizing a fecal Helicobacter pylori antigen. The need to develop such a test arose from disadvantages of the diagnostic test that uses a polyclonal antibody or plural kinds of monoclonal antibodies, such as the lower specificity for H. pylori antigen and the difficulty of reproduction with consistent quality. Mice were immunized with sonicated cells of the coccoid form of H. pylori, and fecal samples from H. pylori-positive subjects were screened by a direct sandwich enzyme immunoassay (EIA) for antibody production from 32 hybridoma clones. The three stable clones produced antibodies (21G2, 41A5, and 82B9) that reacted with the same soluble antigen. Gel filtration chromatography showed that the molecular masses of the cellular antigen and the fecal antigen were the same, 260 kDa. The antigen was labile in response to sodium dodecyl sulfate and heat treatments. A single-step direct sandwich EIA using a single monoclonal antibody, 21G2, was developed. The EIA could detect the antigen in 41 H. pylori clinical isolates and in fecal samples from seven H. pylori-positive subjects. Several kinds of Helicobacter species (Helicobacter felis, Helicobacter hepaticus, Helicobacter mustelae, and Helicobacter cinaedi) except H. pylori, major bacteria in feces (Campylobacter jejuni, Bacteroides vulgatus, Bifidobacterium breve, Bifidobacterium infantis, and Escherichia coli), and fecal samples from six H. pylori-negative subjects showed negative results. These results indicate that the new monoclonal antibodies and the new specific EIA would be useful as a noninvasive method of diagnosis of H. pylori infection.

Animals↗
PubMed2002

Catalase, a specific antigen in the feces of human subjects infected with Helicobacter pylori.

Recently, we reported the production of three new monoclonal antibodies with high specificity for a Helicobacter pylori antigen suitable for diagnosis of H. pylori infection. The aim of the present study was to identify the antigen recognized by these monoclonal antibodies concerning both H. pylori and the feces of human subjects infected with H. pylori. The cellular antigen was purified from an H. pylori cell extract by immunoaffinity column chromatography with the monoclonal antibody as a ligand. The amino-terminal amino acid sequences (eight residues) of the purified antigen and H. pylori catalase were the same. The molecular weights of native and subunit, specific catalase activity, and UV and visible spectra of the purified antigen were in good agreement with those of H. pylori catalase. The human fecal antigens were purified from two fecal samples of two H. pylori-positive subjects by ammonium sulfate precipitation, CM-Sephadex C(50) chromatography, and the same immunoaffinity chromatography used for the H. pylori cellular antigen. The fecal antigens had catalase activity. The amino-terminal amino acid sequences (five residues) of the human fecal antigen and H. pylori catalase were the same. The monoclonal antibodies reacted with the native cellular antigen, but did not react with the denatured antigen, human catalase, and bovine catalase. The results show that the target antigen of the monoclonal antibodies is native H. pylori catalase and that the monoclonal antibodies are able to specifically detect the antigen, which exists in an intact form, retaining the catalase activity in human feces.

Antibodies, Monoclonal↗
PubMed2002

[Lung cancer screening--its efficacy and limitations].

Although the purpose of cancer screening is to decrease the number of cancer deaths, the efficacy of some cancer screening programs has not been proved. This article describes the authorized method for the lung cancer screening system in Japan, and introduces papers reporting the efficacy of lung cancer screening. The problems in the present lung cancer screening system in Japan are also discussed.

Cytodiagnosis↗
PubMedDate not supplied

The efficacy of sputum cytology in mass screening program for early detection of lung cancer.

BACKGROUND: In order to evaluate the efficacy of sputum cytology in lung cancer screening, we re-analyzed the data obtained in our previous case-control study. MATERIALS AND METHODS: The source population was defined as the previous screenees for reducing self-selection bias. Matching conditions were: gender, year of birth, municipality and smoking history. RESULTS: Smoking adjusted odds ratio (SAOR) of dying from lung cancer for those screened by chest roentgenogram (CXp) only vs. not screened was 0.47, and that for those screened by sputum cytology (SpC) & CXp vs. not screened was 0.36, which was approximately three-fourths of the former. In another analysis, SAOR for those screened by SpC & CXp vs. those screened by CXp only was 0.63. CONCLUSION: Although statistical significance was not obtained, there might be some possibility that the risk of lung cancer death in smokers would decrease by additional SpC, compared with CXp only.

Aged↗