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Biomedical subjects

S Fujimura

Publications and source records attributed to S Fujimura.

At least 19 recordsLinked to original sources
PubMed2001

Germinal center-associated nuclear protein (GANP) has a phosphorylation-dependent DNA-primase activity that is up-regulated in germinal center regions.

Antigen stimulation induces a rapid proliferation of B cells for expansion of specific B cell clones and their further differentiation into antibody-producing cells in germinal centers of T-dependent antigen-immunized mice. Previously, we identified a 210-kDa germinal center-associated nuclear protein (GANP) that is up-regulated selectively in germinal centers and carries an MCM-binding domain in the carboxyl-terminal side. In addition, here, we found a region (from 414 to 550 aa) in GANP molecule that is slightly similar to the known DNA-primase component p49. The recombinant GANP fragment covering this region synthesizes RNA primers for extension by DNA polymerase I with single-stranded DNA templates in vitro. GANP DNA-primase activity is controlled by phosphorylation at Ser(502) that is induced by CD40-mediated signaling in vitro and in the germinal center B cells stimulated with antigen in vivo. Overexpression of ganp cDNA in Daudi B cells caused the increased DNA synthesis more than the levels of the mock-transfectants. These evidences suggested that the novel DNA-primase GANP is involved in regulation of cell proliferation of antigen-driven B cells in germinal centers.

Acetyltransferases↗
PubMed2001

A case-control study for evaluating the efficacy of mass screening program for lung cancer in Miyagi Prefecture, Japan.

BACKGROUND: In Miyagi Prefecture, Japan, a mass screening program for lung cancer has been conducted since 1982 (miniature chest X-ray for all screenees and sputum cytology for those with a smoking index > or = 600) [smoking index 600 = 30 pack years, the average number of cigarettes smoked per day multiplied by the number of years of regular smoking]. Over 1500 lung carcinomas, including 250 roentgenographically occult lung tumors, were detected and treated up to 1999. In the current study, a nested case-control study was conducted in the population that was screened in 1989 to evaluate the efficacy of the screening program for lung cancer. METHODS: To reduce self-selection bias, the source population was defined as screenees with negative results in 1989 (284,226 individuals). In the population, 474 individuals died of lung carcinoma during 1992-1994. After exclusion, 328 patients who died of primary lung carcinoma at between ages 40 years and 79 years were defined as the cases. Six controls were supposed to be selected in the source population for each case and matched by gender, year of birth, municipality, and smoking habits. Controls who had died or moved before the matched case was diagnosed were excluded. Finally, 328 cases and 1886 controls were selected. Screening histories were compared, and odds ratios were calculated using conditional logistic regression analysis. RESULTS: Within the 12 months before diagnosis, 241 of 328 cases (73.5%) had attended the screening compared with 1557 of 1886 controls (82.6%). The smoking-adjusted odds ratio was 0.54 (95% confidence interval, 0.41-0.73). CONCLUSIONS: The mass screening program for lung cancer in Miyagi Prefecture was capable of reducing by 46% the risk of death from carcinoma of the lung.

Adult↗
PubMed2001

Specific recognition of cytosolic thymidine kinase in the human lung tumor by monoclonal antibodies raised against recombinant human thymidine kinase.

Anti-TK monoclonal antibodies (mAbs) were raised against recombinant human cytosolic thymidine kinase (rhTK) and characterized by Western immunoblotting, enzyme-linked immunosorbent assay (ELISA) and immunostaining of tumor cells. Twenty-three clones of TK mAbs were characterized to recognize specifically not only rhTK produced by Escherichia coli but also TK subunit of 25 kDa in human lung cancer. The anti-TK mAbs reacted specifically with cytosolic TK but not with mitochondrial TK. Only one clone of the mAbs inhibited the catalytic activity of TK. By solid phase sandwich enzyme immunoassay using these mAbs, we could quantitate the cytosolic TK content in tissues. Immunohistochemical staining analysis using one of the TK mAbs showed that human lung adenocarcinoma and squamous cell carcinoma exhibited much higher staining intensity than stromal cells. These mAbs are useful for biochemical studies on the regulation of human TK in proliferating cells such as tumor cells and for diagnosis of highly proliferating tumors.

Adenocarcinoma↗
PubMed2001

Heterogeneous nuclear ribonucleoprotein B1 as early cancer biomarker for occult cancer of human lungs and bronchial dysplasia.

Heterogeneous nuclear ribonucleoprotein (hnRNP) B1 is a RNA-binding protein of Mr 37,000. We previously reported that hnRNP B1 was specifically overexpressed in the nuclei of human lung cancer cells, particularly in squamous cell carcinoma (E. Sueoka et al., Cancer Res., 59: 1404-1407, 1999). We extended this study to determine whether hnRNP BL was overexpressed in roentgenographically occult cancers of the lungs and premalignant lesions of squamous cell carcinomas, such as bronchial dysplasia. The additional object of our study was to examine the usefulness of hnRNP B1 as a potential diagnostic marker for squamous cell carcinoma of various organs, such as the oral cavity and esophagus in humans. Surgically resected specimens of bronchial dysplasia, lung cancers, and various human squamous cell carcinomas, collected at two hospitals in Japan, were subjected to immunohistochemical staining with anti-hnRNP B1 antibody. Overexpression of hnRNP B1 protein was observed in 100% of stage I lung cancer tissues, but it was not found in normal bronchial epithelium. Squamous cell carcinoma of the lungs showed stronger staining than other histological types, and elevation of hnRNP B1 was found in both roentgenographically occult lung cancers and bronchial dysplasia. Furthermore, cytological examination with anti-hnRNP B1 antibody detected cancer cells in sputum, suggesting the potential of hnRNP B1 protein as a new biomarker for the very early stage of lung cancer in humans. Because strong staining of hnRNP B1 was also observed in various squamous cell carcinomas of oral and esophageal tissues as shown in our recent reports, overexpression of hnRNP B1 seems to be a common event in the carcinogenic processes of squamous cell carcinoma. These results suggest that hnRNP B1 protein could be a useful diagnostic biomarker for both the very early stages of lung cancer and various squamous cell carcinomas in humans.

Adenocarcinoma↗
PubMed2001

Production of monoclonal antibodies against mammalian Ring1B proteins.

The Polycomb group (PcG) genes play a role of transcriptional repressor for long-term maintenance of the Hox cluster gene expression. Recently two structurally similar gene products, Ring1A and Ring1B, were identified. Genetic evidence has indicated that Ring1A has Pc-G properties, however, Ring1B functions are still unknown. To gain functional insights for Ring1B, we raised the mouse monoclonal antibodies (MAbs) against murine Ring1B protein. Using these antibodies, we have detected specifically mouse, human and monkey Ring1B gene products from whole cell extracts in immunoblot and immunoprecipitation analyses. Immunofluorescent staining by the antibodies has shown that endogenous Ring1B proteins clearly co-localize with Ring1A at the pattern of diffuse nuclear speckles. Together with their sequence similarity, Ring1B also may function as a Pc-G protein. Finally, we have proposed that the anti-Ring1B would be useful for biochemical and cytological analyses of Ring1B and Pc-G complex.

Animals↗
PubMed2001

Leupeptin-induced appearance of partial fragment of betaine homocysteine methyltransferase during autophagic maturation in rat hepatocytes.

A cytosolic enzyme, betaine homocysteine methyltransferase (BHMT), and its partial fragments were discovered as autolysosomal membrane proteins from rat liver in the presence of leupeptin [Ueno et al. (1999) J. Biol. Chem. 274, 15222-15229]. The present study was undertaken to further characterize the transport and processing of BHMT from cytosol to autolysosome and to test if the fragment can be used as an in vitro probe for the maturation step of macroautophagy. Upon subcellular fractionation, BHMT (p44) was found in all fractions, while its 32-kDa fragment (p32) was found only in the mitochondrial-lysosomal (ML) fraction. Incubation of isolated hepatocytes with leupeptin induced time-dependent accumulation of p32 in the ML fraction from 30 to 90 min after the start of incubation. However, chloroquine completely inhibited the appearance of p32, indicating that the processing from p44 to p32 is lysosomal. Incubation with Bafilomycin A(1), a vacuolar H(+)-ATPase inhibitor, together with leupeptin, led to linear accumulation of p44, but not of p32. The p44 accumulation rate was calculated to be 4.9%/h, which was comparable to autophagic sequestration rate. The distribution of p44 within the ML fraction turned out to be dual, i.e., the membrane-surface attached and luminal/sedimentable forms. Amino acids and 3-methyladenine, both of which specifically suppress macroautophagy, inhibited the accumulation of p32 as well as of p44. Finally, energy-dependent appearance of p32 was demonstrated during incubation of postnucler supernatant fractions, making it possible to establish an in vitro assay system. All the results strongly support the idea that BHMT is taken up and degraded to p32 through the macroautophagic pathway, and that p32 could be a novel probe for the maturation of macroautophagy.

Animals↗
PubMed2001

Generation of oxidative stress contributes to the development of pulmonary hypertension induced by hypoxia.

Chronic hypoxia causes pulmonary hypertension and right ventricular hypertrophy associated with pulmonary vascular remodeling. Because hypoxia might promote generation of oxidative stress in vivo, we hypothesized that oxidative stress may play a role in the hypoxia-induced cardiopulmonary changes and examined the effect of treatment with the antioxidant N-acetylcysteine (NAC) in rats. NAC reduced hypoxia-induced cardiopulmonary alterations at 3 wk of hypoxia. Lung phosphatidylcholine hydroperoxide (PCOOH) increased at days 1 and 7 of the hypoxic exposure, and NAC attenuated the increase in lung PCOOH. Lung xanthine oxidase (XO) activity was elevated from day 1 through day 21, especially during the initial 3 days of the hypoxic exposure. The XO inhibitor allopurinol significantly inhibited the hypoxia-induced increase in lung PCOOH and pulmonary hypertension, and allopurinol treatment only for the initial 3 days also reduced the hypoxia-induced right ventricular hypertrophy and pulmonary vascular thickening. These results suggest that oxidative stress produced by activated XO in the induction phase of hypoxic exposure contributes to the development of chronic hypoxic pulmonary hypertension.

Acetylcysteine↗
PubMed2001

Endothelin receptor antagonist prevents parathyroid cell proliferation of low calcium diet-induced hyperparathyroidism in rats.

Secondary hyperparathyroidism, one of the most frequently encountered disorders of the calcium homeostasis, is characterized by an increase in parathyroid epithelial (PT) cell number, which is crucial from a functional viewpoint. However, it is still unknown what factors are involved in PT cell proliferation. Endothelin-1 (ET-1), a vasoconstrictive peptide, has been shown to act as a mitogen in a variety of cell types. Rat PT cells are reported to synthesize ET-1 and possess its receptors. To test the hypothesis that ET-1 plays a role in PT cell proliferation, we used rat test subjects fed a low calcium diet for 8 weeks (low Ca rats). The number of the proliferating PT cells, measured by proliferating cell nuclear antigen immunostaining, was significantly increased, with striking immunoreactivity of ET-1 in the low Ca rats. An endothelin receptor antagonist, bosentan (100 mg/kg.day), prevented any increase in the proliferation of PT cells in the low Ca rats (14.3 +/- 2.7/1000 PT cells with no bosentan; 2.1 +/- 1.3 with bosentan; P < 0.01). These results indicate that ET-1 is involved in PT cell proliferation in vivo and suggest that blocking of ET receptors may become one of the important therapeutic strategies for preventing secondary hyperparathyroidism.

Animals↗
PubMed2001

[New approaches for excellent operative field during tracheobronchial anastomoses in sleeve pneumonectomy: cardiopulmonary bypass and diseased lung ventilation].

Cardiopulmonary bypass (CPB) and diseased lung ventilation were presented as new methods of oxygenation during carinal reconstruction. Two cases of left sleeve pneumonectomy (SP) were performed for bronchial gland carcinoma through clamshell incisions. Adequate oxygenation and excellent operative fields were provided by CPB in both patients. The postoperative courses of these patients were uneventful, although they developed temporary pulmonary edema that needed mechanical ventilation and appropriate diuretics for several days. One case of patient with squamous cell carcinoma after chemotherapy was successfully treated by right SP through midline sternotomy. Adequate oxygenation and excellent operative fields was obtained by diseased right lung ventilation in this patient. The postoperative course of the patient was uneventful without mechanical ventilation support. These procedures of oxygenation in this paper are considered to be safe and effective methods for carinal reconstruction.

Adult↗
PubMed2001

Experience with fatal interstitial pneumonia after operation for lung cancer.

BACKGROUND: The number of patients with lung cancer is increasing. This study was undertaken to realize the probability, fate and management of acute fatal postoperative complications. Since interstitial pneumonia was one of the most fatal postoperative complications, to know its incidence and fate is very important. METHODS: A total of 2667 patients who underwent thoracotomy caused by malignant tumors during the past 17 years were reviewed and studied. We performed investigations on medical records, chest X-rays, whole-body CT films, operative records and pathological specimens for all inpatients. RESULTS: Nineteen patients died in hospital 30 days after thoracotomy (operative death). Nine patients died in hospital more than 31 days after thoracotomy (hospital death). Eight cases out of 28 patients (operative and hospital deaths) developed and finally died by interstitial pneumonia. Each case was treated with steroids, neutrophil-elastase inhibitor, and/or immunosuppressive agents. These patients could not be selected by any preoperative laboratory examination, such as preoperative pulmonary function tests, serum biochemistry tests, and chest X-ray or CT films. Interstitial pneumonia as a complication of postoperative stage, was fatal and once developed, it was very difficult to save their lives. CONCLUSIONS: Since we reported the cases who died from acute postoperative complications, especially interstitial pneumonia, we could not present effective management. However, in this report, several therapeutic trials that may solve the problems of acute postoperative interstitial pneumonia were proposed.

Acute Disease↗
PubMed2001

[A case of pneumonectomy for lung cancer associated with scleroderma].

A 60-year-old female, diagnosed as scleroderma, was referred to our hospital because of symptoms of common cold and abnormal findings on a chest X-ray. The chest X-ray and CT scan revealed a mass in the left upper field, suspected to invade left anterior chest wall. Moreover, fibrotic changes were observed in the lung field. Cytology by bronchofiberscopy showed squamous cell carcinoma. Evaluation of pulmonary function, including unilateral pulmonary artery occlusion test (UPAO), revealed possibility of lung resection. Subsequently, pneumonectomy with combined resection of left 1st rib was performed. Postoperative course was uneventful and she was discharged. She was admitted again four months after the operation with appetite loss and body weight loss. Further examinations revealed arrhythmia, renal failure, pancreatitis and liver metastasis. Her general conditions grew worse and she died five months after the operation. In conclusion, UPAO was a useful method to determine the functional lung resectability for the case with scleroderma. However, effects of surgical stress for the development of scleroderma remain to be elucidated.

Carcinoma, Squamous Cell↗
PubMed2001

[Recurrence and pulmonary metastasis of extradural paraganglioma in thoracic vertebral canal: report of a case].

A 70-year-old female was operated on for extradural spinal cord tumor in 1982. Microscopic examination revealed the tumor as paraganglioma. Tumor recurred at paravertebral twice in 1985 and 1989, and they were also resected. In 1995, her chest X-ray film showed round tumor in the right upper field. Exploratory open lung biopsy was performed in 1996, and right upper lobectomy was performed according to for malignant lung tumor because intra-operative microscopic findings showed carcinoid or lung metastasis of paraganglioma. Chest wall tumor at paravertebral was resected at the same time. Postoperative microscopic examination revealed the tumors were same as operated paraganglioma. The 2nd thoracotomy was done in 1999, and two chest wall tumors and a pulmonary nodule in right S8 segment were resected. They were recurrence and pulmonary metastasis of paraganglioma. Now 18 years after initial operation, she is out of hospital in tumor free.

Aged↗
PubMed2001

[Japanese cedar pollen in house dust].

Caring for oneself against Japanese cedar pollinosis is important as well as receiving medical-care. Although the importance of avoiding pollen is described in the guideline for nasal allergy medical treatment, however, there is no information for effective dust cleaning for the home. This study examined how many cedar pollens were included in indoor dust in order to obtain basic data whether dust removal for cedar pollen is available for pollinosis suffers. As a result, the study found that there were many Japanese cedar pollens in indoor dust even before the pollen season. Cedar pollen increased with the increasing number of airborne pollen. The highest number of pollen found in one week was approximately 450 pollens in a square meter of a living room floor. The study concluded that cleaning is one of the best way to remove Japanese cedar pollens found in indoor dust.

Dust↗
PubMed2001

[Limited surgery for bronchogenic carcinoma].

In recent years limited operations including wedge resection, segmentectomy and simple lobectomy are getting increased as a treatment of choice for non-small cell lung cancer (NSCLC). However, surgery for lung cancer should be emphasized in terms of postoperative quality of life as well as complete resection or radical resection of the tumor. There have been few number of randomized controlled trials as to limited operation of lung cancer. Thus this kind of procedures such as wedge resection and segmentectomy for stage I NSCLC, and thoracoscopic lobectomy for stage I lung cancer, is not generally evaluated as an alternative treatment to the standard operation at the present time. In this paper current status of limited surgery for lung cancer is reviewed mainly based on recent literatures and results obtained from our experience in Institute of Development Aging and Cancer, Tohoku University.

Adenocarcinoma↗
PubMed2000

A therapeutic approach to roentgenographically occult squamous cell carcinoma of the lung.

BACKGROUND: The significance of limited resections, including wedge resection and segmentectomy, remains controversial because of their curability rates. In the current study, the objective was to determine a strategy for the treatment of patients with roentgenographically occult bronchogenic squamous cell carcinoma (ROSCC) based on the pathologic findings from 184 patients with ROSCC who underwent resection. METHODS: In Miyagi Prefecture, 1422 patients with lung carcinoma were diagnosed during a mass screening program between 1982 and 1995. Among them, 236 patients had ROSCC, and 184 patients with ROSCC underwent pulmonary resection followed by systemic lymph node dissection. RESULTS: Pathologically, only 0.9% of the ROSCCs that were within the range of endoscopic visibility were revealed to have lymph node involvement, whereas 13% of patients with extracartilage invasion had lymph node involvement. Early ROSCC, which means ROSCC that is limited within the cartilaginous layer and is without lymph node involvement, comprised 90% of ROSCCs that measured <10 mm in longitudinal extension, comprised 77% of ROSCCs that measured 10-29 mm in longitudinal extension, and comprised 33% of ROSCCs that measured >30 mm in longitudinal extension. Eighty-nine percent of the tumors with lymph node involvement had extracartilaginous invasion. The 3-year survival rate of patients after undergoing photodynamic therapy was 100% when their tumor was regarded as early ROSCC (i.e., within 10 mm in longitudinal extension and within the range of endoscopic visibility). To date, 18 patients with ROSCC underwent segmentectomy, and all of these patients are alive without tumor recurrence. The incidence rate of multiple lung carcinomas, including synchronous and metachronous tumors, in patients with ROSCC was 22%. CONCLUSIONS: The authors concluded the following: 1) Patients with lesions that are within the range of endoscopic visibility and that measure <10 mm in longitudinal extension are candidates for photodynamic therapy. 2) Patients with lesions that are beyond the range of endoscopic visibility or that measure >10 mm in longitudinal extension are candidates for segmentectomy as long as intraoperative examination shows a tumor free bronchial stump and negative lymph nodes 11-13. 3) Patients with lesions that show bronchial obstruction or extrabronchial invasion should undergo standard resection.

Carcinoma, Squamous Cell↗
PubMed2000

Novel arbekacin- and amikacin-modifying enzyme of methicillin-resistant Staphylococcus aureus.

An aminoglycoside-modifying enzyme in arbekacin-resistant methicillin-resistant Staphylococcus aureus (MRSA), exhibiting 4'''-N-acetylation, was examined. Although the MRSA strain with AAC(4''') had no AAC(6')-APH(2") activity, a DNA fragment of the AAC(6')-APH(2") gene was amplified by PCR and the purified N-terminal 30-amino acid sequence of this AAC(4''') was identical to AAC(6')-APH(2"). Direct DNA sequencing of this 'silent' AAC(6')-APH(2") gene revealed a single point mutation leading to a substitution of Gly for Asp80, through which the secondary structure is affected. A change in protein conformation could lead to a cleavage and a change of the enzymatic activity. We propose a new aminoglycoside-resistance mediated by AAC(4''') is caused by a mutation-modified AAC(6')-APH(2").

Acetyltransferases↗
PubMed2000

A potent inhibitor of inducible nitric oxide synthase, ONO-1714, a cyclic amidine derivative.

(1S,5S,6R,7R)-7-Chloro-3-imino-5-methyl-2-azabicyclo[4.1.0]heptane hydrochloride (ONO-1714), a novel cyclic amidine analogue, inhibits human inducible nitric oxide (iNOS) with a K(i) of 1.88 nM and rodent iNOS with similar potency in vitro. ONO-1714 was found to be 10-fold selective for human iNOS over human endothelial NOS (ecNOS). When the inhibitory activity of ONO-1714 was compared for iNOS, it was found to be 451-fold and >20,000-fold more potent than L-NMMA and aminoguanidine (AG), respectively. In terms of human iNOS selectivity, ONO-1714 was approximately 34- and 2-fold more selective for iNOS than L-NMMA and AG, respectively. ONO-1714 inhibited the LPS-induced elevation of plasma nitrate/nitrite in mice with an ID(50) value of 0.010 mg/kg, s.c. The maximum tolerated dose of ONO-1714 was 30 mg/kg, i.v. Thus, ONO-1714 represents one of the most potent iNOS inhibitors in vitro and in vivo to date and has great potentials for use as an inhibitor for clarifying the pathophysiological roles of iNOS and for use as a therapeutic agent.

Amidines↗