Biomedical subjects

Shinji Yamaguchi

Publications and source records attributed to Shinji Yamaguchi.

At least 19 recordsLinked to original sources

PubMed2006

Involvement of insect-derived growth factor (IDGF) in the cell growth of an embryonic cell line of flesh fly.

Insect-derived growth factor (IDGF) is the first adenosine deaminase-related growth factor (ADGF) purified from the conditioned medium of NIH-Sape-4, an embryonic cell line of Sarcophaga peregrina (flesh fly). Here we show the requirement of IDGF for the growth of NIH-Sape-4 cells. Growth factor activity was abolished by adsorption of IDGF from the conditioned medium of NIH-Sape-4 cells. In addition, knockdown of IDGF gene expression by RNA interference (RNAi) significantly reduced IDGF secretion from the cells following cell growth inhibition. The IDGF gene was strongly expressed in the hemocytes, and IDGF increased the viability of the larval hemocytes. These data provide evidence that IDGF is required for the growth of NIH-Sape-4 cells and possibly for hemocyte viability.

Animals↗

PubMed2006

Characteristics of asthma resistant to moderate dose inhaled corticosteroid treatment on bronchial hyperresponsiveness.

OBJECT: This study was performed to determine the clinical characteristics of asthmatics with bronchial hyperresponsiveness (BHR) that could not be normalized by 6 months of treatment with a moderate dose of an inhaled corticosteroid (ICS). METHODS: Thirty-four symptomatic patients with mild to moderate asthma, who had never received any ICS, were treated with 200 mug of inhaled fluticasone propionate twice a day for 6 months. Spirometry, BHR to methacholine, exhaled nitric oxide (NO) and eosinophils in induced sputum were examined before and 2 and 6 months after beginning treatment. RESULTS: FEV1 was increased and bronchial responsiveness, exhaled NO and sputum eosinophilia were significantly decreased 2 and 6 months after starting ICS treatment. Bronchial responsiveness was further decreased at 6 months together with a further increase in FEV1. In 13 patients, BHR was not normalized despite the 6 months of treatment. This group showed a higher prevalence of males, those with a smoking history and airflow limitation, a higher eosinophil count in the sputum following 6 months of treatment and a longer history of asthma. Multiple, stepwise, linear regression analysis showed that sputum eosinophilia and lower FEV1/FVC following 6 months of treatment and a longer history of asthma were significant independent determinants for BHR after 6 months of ICS treatment. CONCLUSIONS: These findings suggest that the resistance to a moderate dose of ICS for BHR in asthmatics may be significantly associated with remained airflow limitation, eosinophilic airway inflammation resistive to moderate dose of ICS, and delayed introduction of ICS therapy.

Administration, Inhalation↗

PubMed2006

Long-chain fatty acids induce lipid droplet formation in a cultured human hepatocyte in a manner dependent of Acyl-CoA synthetase.

Lipid droplets (LDs) are intracellular storage sites of neutral lipids, which accumulate in fatty liver disease. Here, we investigated the effects of fatty acids and glucose on LD formation in a cultured human hepatocyte, HuH7, by adding them to culture media. Fatty acids with carbohydrate chains C12-C18 efficiently induced LDs, but those of C8 and C10 were ineffective. Glucose did not induce LD formation even in the presence of insulin. Oleic acid induced significant increases in cellular neutral lipids, and cell fractionation revealed that most of the newly synthesized neutral lipids were concentrated in LDs together with LD proteins. The LD formation was not abrogated by removal of medium glucose but was significantly inhibited by an ACSL inhibitor, triacsin C. These results demonstrate that long-chain fatty acids contribute to LD formation to a greater extent than glucose, possibly by being taken up into the cells, activated by ACSL, reconstituted into neutral lipids and then stored in LDs. Pregnenolone and lithium did not suppress oleic acid-dependent LD formation, despite previous reports of their ability to inhibit LD formation in macrophages and adipocytes suggesting differences among LD formations in these cells.

Caffeine↗

PubMed2006

[Successful treatment of intrapericardial administration of carboplatin following systemic chemotherapy in a case of advanced thymic cancer with cardiac tamponade].

A 72-year-old woman developed cardiac tamponade due to direct invasion of thymic cancer. Carboplatin was administered into the pericardial cavity two times with a total dose of 600 mg. Pericardial effusion disappeared without any toxicities. Following four cycles of systemic chemotherapy by carboplatin, doxorubicin, vincristine, cyclophosphamide (ADOC), partial response was obtained. She is alive 10 month after being given a diagnosis of cardiac tamponade. Intrapericardial administration of carboplatin is a useful therapy for control of pericardial effusion and chemosensitive cases should de identified among patients with thymic cancer.

Aged↗

PubMed2005

Klotho insufficiency causes decrease of ribosomal RNA gene transcription activity, cytoplasmic RNA and rough ER in the spinal anterior horn cells.

The klotho gene was identified in 1997 as the gene whose severe insufficiency (kl/kl) causes a syndrome resembling human aging, such as osteoporosis, arteriosclerosis, gonadal atrophy, emphysema, and short life span in a mouse strain. Regarding the gait disturbance reported in kl/kl mice, the present study examined the spinal cord of kl/kl mice, and revealed decreases in the number of large anterior horn cells (AHCs), the amount of cytoplasmic RNA, the number of ribosomes and rough endoplasmic reticulum (rER), and the activity of ribosomal (r) RNA gene transcription without significant loss of the total number of neurons in the ventral gray matter. Increased immunostaining of phosphorylated neurofilament in the AHCs and of glial fibrillary acidic protein in reactive astrocytes in the anterior horn of kl/kl mice were also observed. On the other hand, the posterior horn was quite well preserved. The results suggest that the kl/kl insufficiency causes atrophy and dysfunction of the spinal AHCs through decreased activity of rRNA gene transcription, which may reduce the amount of cytoplasmic RNA and the number of ribosomes and rER. These findings resemble those found in the spinal cord of patients with classic amyotrophic lateral sclerosis (ALS). The results show that klotho gene insufficiency causes dysfunction of the protein synthesizing system in the AHCs, and might indicate the klotho gene is involved in the pathological mechanism of classic ALS. The kl/kl is a new animal model of AHC degeneration, and may provide clues to understanding the etiology of classic ALS.

Animals↗

PubMed2005

Involvement of EDTP, an egg-derived tyrosine phosphatase, in the early development of Drosophila melanogaster.

Previously, we purified a novel protein tyrosine phosphatase from eggs of the flesh fly, Sarcophaga peregrina. This protein tyrosine phosphatase, named egg-derived tyrosine phosphatase (EDTP), is expressed during oogenesis and early embryogenesis but is rapidly degraded in middle embryogenesis by lysosomal cathepsin L. Here, we demonstrate the requirement of EDTP in the development of the fruit fly, Drosophila melanogaster. Deletion of the Drosophila EDTP gene using transposase-catalyzed imprecise excision resulted in homozygous lethals during embryogenesis. Additionally, germline clones generated using the FLP-FRT-ovo(D) system showed severe defects in ovarian development during oogenesis. These results indicate that the Drosophila EDTP gene is crucial in oogenesis and embryogenesis.

Animals↗

PubMed2005

Traumatic dislocation of the hamate and pisiform: a case report and review of the literature.

Isolated dislocation of the hamate bone and pisiform bone is rare. We describe the simultaneous complete dislocation of both the hamate and pisiform bones in a 27-year-old man who crushed his right hand in a rolling press. An open reduction and internal fixation with Kirschner wires was performed. Four weeks later, the Kirschner wires were removed and rehabilitation was started. At 6 months follow-up, the patient had minimal pain and full range of motion in the affected wrist joint and fingers. However, grip strength was 50% compared to his unaffected left hand, and sensation of the ulnar nerve area was reduced to almost 30% of that of his left hand. It appears that the ulnar nerve injury was the largest contributing factor to the poor outcome of our patient. Evaluation of soft-tissue injuries, especially nerve injury, is important in the treatment of complex carpal dislocations.

Adult↗

PubMed2004

Thymic squamous cell carcinoma producing parathyroid hormone-related protein and CYFRA 21-1.

A 54-year-old man was admitted to our hospital because of dyspnea. Radiographic examination showed an anterior mediastinal mass and pericardial effusion. Serum calcium and parathyroid hormone-related protein (PTHrP) levels were elevated, and serum CYFRA 21-1 level was extremely high. Results of percutaneous needle biopsy under computed tomography guidance led to a diagnosis of moderately differentiated squamous cell carcinoma. Immunohistological staining showed the tumor cells to be positive for PTHrP and cytokeratin monoclonal antibodies. Postmortem findings were considered to indicate thymic carcinoma. Thymic carcinoma is rare, but our case indicates that thymic squamous cell carcinoma can be identified in terms of paraneoplastic hypercalcemia.

Antigens, Neoplasm↗

PubMed2003

DHP-insensitive L-type-like Ca channel of ascidian acquires sensitivity to DHP with single amino acid change in domain III P-region.

TuCa1, an ascidian homolog of L-type Ca channel alpha(1)-subunit, has many critical sites required for binding 1,4-dihydropyridines (DHPs), but is insensitive to DHPs and methyl 2,5-dimethyl-4-[2-(phenylmethyl)benzoyl]-1H-pyrrole-3-carboxylate (FPL-64176). We have substituted Ser for Ala(1016) at the P-region of domain III in TuCa1 (TuCa1/A1016S) and functionally expressed the channel in Xenopus oocyte along with rabbit alpha(2)/delta and beta(2b). TuCa1/A1016S has gained DHP sensitivity as high as that of a mammalian neuronal L-type Ca channel (rbCII), but remained resistant to FPL-64176. These results reinforce the view that Ser(1016) in TuCa1/A1016S participates in DHP binding, but there exist other novel sites that fully acquire sensitivity to FPL-64176.

Amino Acid Substitution↗

PubMed2003

Chibby, a nuclear beta-catenin-associated antagonist of the Wnt/Wingless pathway.

Inappropriate activation of downstream target genes by the oncoprotein beta-catenin is implicated in development of numerous human cancers. beta-catenin and its fruitfly counterpart Armadillo act as a coactivator in the canonical Wnt/Wingless pathway by binding to Tcf/Lef transcription factors. Here we report a conserved nuclear protein, named Chibby, which was identified in a screen for proteins that directly interact with the C-terminal region of beta-catenin. In mammalian cultured cells we demonstrate that Chibby inhibits beta-catenin-mediated transcriptional activation by competing with Lef-1 to bind to beta-catenin. Inhibition of Drosophila Chibby by RNA interference results in segment polarity defects that mimick a wingless gain-of-function phenotype, and overexpression of the wingless target genes engrailed and Ultrabithorax. In addition, epistasis experiments indicate that chibby acts downstream of wingless and upstream of armadillo.

Animals↗

PubMed2003

Sputum eosinophilia and bronchial responsiveness in patients with chronic non-productive cough responsive to anti-asthma therapy.

OBJECTIVE: We aimed to examine airway inflammation and bronchial responsiveness in patients with chronic non-productive cough responsive to anti-asthma therapy. METHODOLOGY: Bronchial responsiveness to methacholine as well as the number of inflammatory cells and concentration of eosinophil cationic protein (ECP) in induced sputum were measured in 42 patients with chronic non-productive cough of unknown origin. Their response to bronchodilator, antiallergic and inhaled or oral glucocorticoid therapy was subsequently assessed. RESULTS: Complete remission of coughing was attained with anti-asthma therapies in 34 patients (responder group), while eight patients did not respond (non-responder group). Twenty patients in the responder group and three in the non-responder group showed bronchial hyperresponsiveness (BHR). The number of eosinophils and ECP levels in the sputum from responders with BHR were significantly increased when compared with those from non-responders and healthy subjects. These sputum measures were also significantly increased in responders without BHR when compared with healthy subjects. However, there were no significant differences in these inflammatory markers between the responders with and without BHR. The neutrophil numbers in the sputum from non-responders and responders both with and without BHR were also significantly higher than in control subjects, but there were no significant differences. CONCLUSIONS: These findings suggest that patients with chronic non-productive cough responsive to anti-asthma therapy characteristically have eosinophilic airway inflammation, which may play an important role in the development of chronic cough. Furthermore, the evaluation of not only bronchial responsiveness but also airway inflammation by examination of induced sputum may be useful for diagnosis and deciding on therapeutic strategies.

Adult↗

PubMed2003

Key roles of Phe1112 and Ser1115 in the pore-forming IIIS5-S6 linker of L-type Ca2+ channel alpha1C subunit (CaV 1.2) in binding of dihydropyridines and action of Ca2+ channel agonists.

Voltage-dependent L-type Ca2+ channels are modulated by the binding of Ca2+ channel antagonists and agonists to the pore-forming alpha1c subunit (CaV 1.2). We recently identified Ser1115 in IIIS5-S6 linker of alpha1C subunit as a critical determinant of the action of 1,4-dihydropyridine agonists. In this study, we applied alanine-scanning mutational analysis in IIIS5-S6 linker of rat brain alpha1C subunit (rbCII) to illustrate the role of pore-forming IIIS5-S6 linker in the action of Ca2+ channel modulators. Ca2+ channel currents through wild-type (rbCII) or mutated alpha1C subunits, transiently expressed in BHK6 cells with beta1a and alpha2/delta subunits, were analyzed. The replacement of Phe1112 by Ala (F1112A) significantly impaired the sensitivity to Ca2+ channel agonists (S)-(-)-Bay k 8644 and FPL-64176, and modestly to 1,4-dihydropyridine (DHP) antagonists. The low sensitivity of F1112A and S1115A to DHP antagonists was consistent with the reduced binding affinity for [3H](+)PN200-110. The replacement of Phe1112 by Tyr, but not by Ala, restored the long openings produced by FPL-64176, thus indicating the critical role of aromatic ring of Phe1112 in the Ca2+ channel agonist action. Interestingly, double-mutant Ca2+ channel (F1112A/S1115A) failed to discriminate between Ca2+ channel agonist (S)-(-)-1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-[trifluoromethyl] phenyl)-3-pyridine carboxylic acid methyl ester (Bay k 8644) and antagonist (R)-(+)-Bay k 8644 and was blocked by the two enantiomers in an identical manner. These results indicate that both Phe1112 and Ser1115 in linker IIIS5-S6 are required for the action of Ca2+ channel agonists. A model of the DHP receptor is proposed to visualize possible interactions of Phe1112, Ser1115, and other DHP-sensing residues with a typical DHP ligand nifedipine.

Alanine↗

PubMed2003

[Telemedicine support system in home care of patients with chronic respiratory failure: preliminary results].

We report the preliminary results of an advanced telemedicine system for the delivery of home care services. We have been trying out a system for a ternary telemedicine network for remote consultation in patients with chronic respiratory failure. The elements of this system are: the patients at home, the home doctor (and/or community hospital), and an institution with respiratory staff (Shinshu University), which were linked by ISDN lines. The system allows real-time visualization, at home, of the patients and their physiological data, which are transmitted simultaneously to both the community hospital and Shinshu University. Respiratory specialists can advise the home doctor on the treatment and follow-up evaluations of distant patients. We consider that the telemedicine network system has the potential to improve clinical outcomes and to provide home care services to patients with chronic health conditions.

Aged↗

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

RNAi is activated during Drosophila oocyte maturation in a manner dependent on aubergine and spindle-E.

Gene silencing by double-stranded RNA is a widespread phenomenon called RNAi, involving homology-dependent degradation of mRNAs. Here we show that RNAi is established in the Drosophila female germ line. mRNA transcripts are translationally quiescent at the arrested oocyte stage and are insensitive to RNAi. Upon oocyte maturation, transcripts that are translated become sensitive to degradation while untranslated transcripts remain resistant. Mutations in aubergine and spindle-E, members of the PIWI/PAZ and DE-H helicase gene families, respectively, block RNAi activation during egg maturation and perturb translation control during oogenesis, supporting a connection between gene silencing and translation in the oocyte.

Adenosine Triphosphatases↗

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

Benefits of oxygen on exercise performance and pulmonary hemodynamics in patients with COPD with mild hypoxemia.

STUDY OBJECTIVES: To clarify the effects of oxygen on exercise performance and pulmonary hemodynamics during exercise in patients with COPD with mild hypoxemia at rest. DESIGN: Seventy-five male patients with stable COPD ("pink puffer" type), accompanied by mild hypoxemia (> 60 mm Hg) at rest and with mild (percentage of predicted FEV1 [%FEV1] > 50%, n = 16), moderate (%FEV1 > 35% to < or = 50%, n = 25), and severe (%FEV1 < or =35%, n = 34) airflow obstruction were recruited from an outpatient clinic. A 6-min walking distance (6MD) test was administered to 75 patients, and the pulmonary hemodynamics of 43 subjects were determined during exercise on a supine bicycle ergometer at 25 W and breathing compressed air and oxygen at 2 L/min. RESULTS: Supplemental oxygen resulted in a significant increase in 6MD, except for patients with mild airflow obstruction and mild desaturation. This increase in 6MD produced by oxygen was greater as the restriction of the airflow was more severe, and correlated negatively with %FEV1, but not with PaO2 at rest or exercise hypoxemia. Pulmonary artery pressure (Ppa) and pulmonary artery occlusion pressure (Pop) increased with exercise, while the rates of increase in both types of pressure were significantly higher for severe COPD than for mild COPD and moderate COPD. Oxygen inhalation significantly reduced the increases in Ppa and Pop during exercise in patients with moderate-to-severe COPD, and the effect of oxygen on the increase in Pop correlated positively with airtrapping (vital capacity - FVC). CONCLUSION: These findings suggest that supplemental oxygen benefits patients with COPD with moderate-to-severe airflow obstruction and mild hypoxemia at rest, as reflected in improvement in exercise performance and pulmonary hypertension during exercise.

Aged↗

PubMed2002

Successful salvage therapy of irinotecan for relapsed Hodgkin's lymphoma.

A 30-year-old man, who had a repeated history of relapsed Hodgkin's lymphoma over 7 years, developed bilateral pleural effusion and chest wall involvement. He was treated with weekly irinotecan hydrochloride (CPT-11; 80 mg/m2/week). Partial response was observed after two cycles of irinotecan. Neutropenia and diarrhea were tolerable. This case demonstrated that irinotecan has a therapeutic effect in patients with relapsed Hodgkin's lymphoma.

Adult↗