Biomedical subjects

M Sekiguchi

Publications and source records attributed to M Sekiguchi.

At least 73 records · Page 4Linked to original sources

PubMed2000

RT-PCR suggests human skeletal muscle origin of alveolar soft-part sarcoma.

In 1952, Christopherson et al. proposed that alveolar soft-part sarcoma (ASPS) was a distinct entity with unique clinical and pathological features. Since their report, its histogenesis has not been determined. In order to clarify the histogenesis of ASPS, a study using reverse transcription polymerase chain reaction using cDNAs from MyoD1 and myogenin, and the actin filament from human-skeletal-muscle-related mRNAs has been performed in 5 cases of ASPS. The expression of MyoD1 and myogenin was determined in 5 and 2 cases of the 5 cases, respectively. Moreover, expression of the many mRNAs from the actin filament of skeletal muscle was also found in ASPS. According to these findings, it is now postulated that ASPS is of skeletal muscle origin.

Actins↗

PubMed2000

Pulmonary function tests of Mycobacterium avium-intracellulare infection: correlation with bronchoalveolar lavage fluid findings.

BACKGROUND: The pulmonary Mycobacterium avium-intracellulare (MAI) infection in patients with neither predisposing lung disease nor immunodeficiency is recognized to occur predominantly in older or middle-aged and thin females, and has characteristic chest computed tomography (CT) findings with multiple nodules and bronchiectasis. OBJECTIVE: To investigate the pathophysiology with and individual of MAI infection with neither predisposing lung disease nor immunodeficiency. The bronchoalveolar lavage (BAL) fluid (BALF) was recovered directly from the affected segments identified by the chest CT. METHODS: We performed a pulmonary function test (PFT) and BAL in 15 patients (all females) with MAI infection and 5 normal female volunteers. RESULTS: The residual volume and the slope of phase III (DeltaN(2)) were significantly increased and V(25) was significantly decreased in the 15 patients compared with the normal control subjects. The patients' BALF showed significant increases in neutrophils and activated CD4 lymphocytes, proinflammatory cytokines, and neutrophil elastase (NE) compared to those in the controls. We analyzed the PFT and BALF findings, and observed a significant correlation between the DeltaN(2) and interleukin (IL)-8 concentration (r = 0.65, p < 0.01), IL-8/albumin ratio (r = 0.51, p < 0.05) and NE/albumin ratio (r = 0.57, p < 0.05) in the BALF and DeltaN(2), respectively. CONCLUSIONS: These findings suggest that small airway dysfunction in MAI infection without predisposing lung disease is related to the inflammation probably related to the neutrophil.

Aged↗

PubMed2000

Spontaneous pneumomediastinum in 33 patients: yield of chest computed tomography for the diagnosis of the mild type.

BACKGROUND: Spontaneous pneumomediastinum (SPM) usually occurs in young people without an apparent precipitating factor or disease. Although there have been many studies focused on the clinical features and standard chest X-ray (CXR) findings of SPM, few have reviewed the chest computed-tomographic (CT) findings. OBJECTIVES: We assessed SPM using CXR and CT, and the relation between them. METHODS: We evaluated 33 patients (26 males) diagnosed with SPM on the basis of symptoms and chest radiological findings. RESULTS: Three patients showed normal CXR but a diagnostic CT scan. Seven showed mild pneumomediastinum on CXR. In these 10 patients, pneumomediastinum was easily detected by chest CT. Moderate and severe SPM were easily detected by both CXR and CT. CONCLUSIONS: These findings suggested that CXR alone poorly detected approximately 30% of SPM and that chest CT scan was needed to make the diagnosis in these cases. It seems likely that SPM is underdiagnosed by 30% or more in clinical practice.

Adolescent↗

PubMed2000

Pulmonary hypertension as a result of asymptomatic portosystemic shunt.

This report describes a patient with severe pulmonary hypertension accompanied by a congenital intrahepatic portosystemic shunt. Primary pulmonary hypertension was suspected initially because none of the classic symptoms of a portosystemic shunt were present. Physicians should note that disorders of the portal system may cause pulmonary hypertension even in the absence of symptoms suggesting liver disease.

Female↗

PubMed2000

h-Caldesmon as a specific marker for smooth muscle tumors. Comparison with other smooth muscle markers in bone tumors.

Caldesmon is a protein widely distributed in smooth and non-smooth muscle cells and is thought to regulate cellular contraction. Its isoform, high-molecular-weight caldesmon (h-CD), was demonstrated to be specific for smooth muscle cells and smooth muscle tumors of the soft tissue and to never be expressed in myofibroblasts. We performed an immunohistochemical study to examine h-CD expression in the following bone tumors: conventional and non-conventional osteosarcoma, 13; malignant fibrous histiocytoma of bone, 5; giant cell tumors of bone, 5; chondroblastoma, 3; metastatic leiomyosarcoma, 2; and rhabdomyosarcoma, 1. Frequent immunoreactivity for muscle actin (alpha-smooth muscle actin or muscle-specific actin) was seen in 11 of 13 osteosarcomas and all other tumors, whereas h-CD was expressed intensely only in 2 leiomyosarcomas. h-CD is considered a specific and useful marker to distinguish smooth muscle tumor from bone tumors with myoid differentiation.

Adolescent↗

PubMed2000

Inflammatory myofibroblastic tumor (inflammatory fibrosarcoma) of the bone.

Although inflammatory myofibroblastic tumors, originally described in the lung, have recently been recognized to occur in various sites, their origin in bone is exceptional. We present a case of inflammatory myofibroblastic tumor, so-called inflammatory fibrosarcoma, of the bone. The tumor occurred in the iliac bone of a 70-year-old woman. Standard radiographs and magnetic resonance imaging revealed a destructive bone tumor that expanded into the soft tissue. Although the patient underwent excision of the hemi-iliac bone, multiple pulmonary metastases were noted 1 year after the operation. On histologic examination, the tumor was found to be composed of a sarcoma-like cellular area and a hypocellular fibrous area. Inflammatory cell infiltration into the tumor was a distinctive feature and is analogous with that of conventional inflammatory myofibroblastic tumor or inflammatory fibrosarcoma of the soft tissue. This is the first report to our knowledge of an inflammatory myofibroblastic tumor of the bone with distant metastasis.

Aged↗

PubMed2000

[Utility of Ringer's acetate solution as an intraoperative fluid during cardiovascular surgery with cardiopulmonary bypass].

This study aimed to clarify the difference in the effects of Ringer's acetate (AR) and Ringer's lactate (LR) administration during cardiovascular surgery with cardiopulmonary bypass. We evaluated their effects on intra and postoperative metabolism, liver functions, blood gas and hemodynamic states. Twenty patients were divided into two groups; AR group (n = 10) and LR group (n = 10). Intraoperative serum D-lactate levels in LR group were significantly higher than those in AR group from the beginning of the operation to awakening. Serum acetate levels showed no increase in both groups. The arterial ketone body ratio (AKBR) in AR group was higher than that in LR group, but the difference was not significant. Serum glutamic pyruvic transaminase (GPT) and alkaline phosphatase (ALP) levels in LR group were significantly higher than those in AR group from the induction of the anesthesia. It has been reported that acetate has a greater vasodialatory effect than lactate. However, our findings indicate no significant difference in hemodynamics between the two groups. These results suggest that AR may be more useful than LR during cardiovascular surgery with cardiopulmonary bypass.

Adult↗

PubMed2000

[From arrhythmogenic right ventricular dysplasia/cardiomyopathy(ARVD/ARVC) to a broader concept of ABCDE syndrome].

The concept on the presence of a peculiar disease, arrhythmogenic right ventricular cardiomyopathy, has been widely recognized to be involved in the category of cardiomyopathy. The authors believe this disease entity should be further expanded, and propose the new term "ABCDE Syndrome", abbreviated from Arrhythmogenicity, Brugada syndrome, Competitive sports, Death(especially sudden death) and Electric disturbance type of cardiomyopathy(ECM), be incorporated to encompass all facets of this category.

Arrhythmogenic Right Ventricular Dysplasia↗

PubMed2000

[Myocardial sarcoidosis].

In this review article, clinical features characteristic of myocardial sarcoidosis including illness course, prognosis and treatment strategies are discussed. The pearl of settling the diagnosis of cardiac sarcoidosis is to consider cardiac involvement in all sarcoidosis patients, electrocardiographic and echocardiographic evidence is of greatest importance.

Anti-Inflammatory Agents↗

PubMed2000

[Anesthetic management of a patient with latex allergy diagnosed preoperatively].

Since the first report in 1979, the number of patients with latex allergy has progressively increased. We experienced an anesthetic management of a 3 year-old child who underwent the repair of anal atresia. The first operation was performed in newborn period. After the surgery, the patient developed skin rash and the loss of consciousness every time anal irrigation was made with latex-containing catheter. Latex-allergy was diagnosed at the age of 3 years, with the positive skin test by latex extract. It took enormous time and efforts to find out the possibility of latex-contamination in a wide variety of medical equipments and supplies to prevent allergic reaction during perioperative period. In this patient, perioperative cause was uneventful. It is suggested that preoperative preparation is essential and caution should be also paid to prevent allergic reaction in daily life.

Anesthesia, General↗

PubMed1999

Functional significance of the conserved residues for the 23-residue module among MTH1 and MutT family proteins.

Human MTH1 and Escherichia coli MutT proteins hydrolyze 7, 8-dihydro-8-oxo-dGTP (8-oxo-dGTP) to monophosphate, thus avoiding the incorporation of 8-oxo-7,8-dihydroguanine into nascent DNA. Although only 30 amino acid residues (23%) are identical between MTH1 and MutT, there is a highly conserved region consisting of 23 residues (MTH1, Gly(36)-Gly(58)) with 14 identical residues. A chimeric protein MTH1-Ec, in which the 23-residue sequence of MTH1 was replaced with that of MutT, retains its capability to hydrolyze 8-oxo-dGTP, thereby indicating that the 23-residue sequences of MTH1 and MutT are functionally and structurally equivalent and constitute functional modules. By saturation mutagenesis of the module in MTH1, 14 of the 23 residues proved to be essential to exert 8-oxo-dGTPase activity. For the other 9 residues (40, 42, 44, 46, 47, 49, 50, 54, and 58), positive mutants were obtained, and Arg(50) can be replaced with hydrophobic residues (Val, Leu, or Ile), with a greater stability and higher specific activity of the enzyme. Indispensabilities of Val(39), Ile(45), and Leu(53) indicate that an amphipathic property of alpha-helix I consisting of 14 residues of the module (Thr(44)-Gly(58)) is essential to maintain the stable catalytic surface for 8-oxo-dGTPase.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Localization of the ATP-sensitive potassium channel subunit (Kir6. 1/uK(ATP)-1) in rat brain.

The Kir6.1/uK(ATP)-1, subunit of ATP-sensitive K(+) channels (K(ATP)), was localized in adult rat brain by in situ hybridization and immunohistochemistry. The mRNA of this subunit was ubiquitously expressed in various neurons and nuclei of the adult rat brain. Interestingly, Kir6.1/uK(ATP)-1 mRNA was also expressed in glial cells. Kir6.1/uK(ATP)-1 protein staining gave a dispersed array of fine dots throughout all neurons and glial cells examined. Under electron microscope, the immunoreactive products were specifically restricted to the mitochondria. The present study indicates that this K(ATP) subunit is localized in the mitochondria and may play a fundamental role in vital brain function.

Adenosine Triphosphate↗

PubMed1999

Potentiating effects of 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyaceta mide (PEPA) on excitatory synaptic transmission in dentate granule cells.

A novel sulfonylamino compound, 4-[2-(phenylsulfonylamino)-ethylthio]-2,6-difluoro-phenoxyaceta mide (PEPA) has been shown to selectively potentiate glutamate-induced currents in Xenopus oocytes expressing recombinant AMPA receptor subunits, GluR1-GluR4, by attenuation of desensitization. Here, we examined the effects of PEPA on responses to excitatory amino acids as well as on excitatory synaptic transmission in dentate granule cells of rat hippocampal slices using the whole-cell patch clamp technique. PEPA at 100 microM produced a 3-4-fold increases in the peak amplitude of current responses to AMPA and glutamate applied iontophoretically in the dentate granule cells, whereas it showed no effect on NMDA-induced currents. Excitatory postsynaptic currents (EPSCs) evoked in these neurons by stimulation of the perforant path had fast and slow components mediated by AMPA and NMDA receptors, respectively. PEPA at concentrations between 10 and 100 microM potentiated only the AMPA component of the EPSC (AMPA EPSC) in a dose-dependent manner without affecting the NMDA component. Although the potentiating effect of PEPA on the amplitude of the AMPA EPSC was weaker than that on the AMPA-induced current, it clearly prolonged the duration of the EPSC. PEPA at 100 microM increased the peak amplitude of the AMPA EPSC by 17%, and increased the area enclosed by the AMPA EPSC by 72%.

Animals↗

PubMed1999

Transfection analysis of functional roles of complexin I and II in the exocytosis of two different types of secretory vesicles.

Classical neurotransmitters such as gamma-aminobutyric acid and glutamate are released from synaptic nerve terminals by exocytosis of synaptic vesicles. PC12 cells also have SSVs capable of storing acetylcholine (ACh). A novel method to examine the effect of transient transfection of any gene of interest on the exocytosis of SSVs was developed. The transfection of choline acetyltransferase (ChAT) into PC12 cells which have lost ACh synthesizing activity resulted in the accumulation of a substantial amount of ACh. Synthesized ACh was released in Ca(2+)-dependent manner. Release was thought to occur by an exocytosis of SSVs because: (1) release was abolished by treating the cells with vesamicol, a specific inhibitor of the vesicular ACh transporter (VAChT) localizing specifically in SSVs; and (2) the release was further increased by cotransfecting rat VAChT with the ChAT. By means of this method, we showed that overexpression of complexin I or II with ChAT markedly suppressed high-K(+)-dependent ACh release of SSVs.

Acetylcholine↗

PubMed1999

Multi-forms of human MTH1 polypeptides produced by alternative translation initiation and single nucleotide polymorphism.

The human MTH1 gene for 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase, produces seven types (types 1, 2A, 2B, 3A, 3B, 4A and 4B) of mRNAs. The B-type mRNAs with exon 2b-2c segments have three additional in-frame AUGs in their 5' regions. We report here that these transcripts produce three forms of MTH1 polypeptides (p22, p21 and p18) in in vitro translation reactions. Three polypeptides were also detected in extracts of human cells, using western blotting. B-type mRNAs with a polymorphic alteration (GU-->GC) at the beginning of exon 2c that converts an in-frame UGA to CGA yielding another in-frame AUG further upstream, produced an additional polypeptide (p26) in vitro. Substitution of each AUG abolished the production of each corresponding polypeptide. Cell lines from individuals with the GC allele contain more B-type mRNAs than do those of GT homozygotes, and the former produce all of four polypeptides but the latter lack p26. Amounts of each polypeptide reflected copy number of the GC allele in each cell line. There is an apparent linkage dis-equilibrium between the two polymorphic sites, GT/GC at exon 2c and Val83/Met83 at codon 83 for p18.

Base Sequence↗

PubMed1999

Tissue distribution of prolactin-releasing peptide (PrRP) and its receptor.

Prolactin-releasing peptide (PrRP) is a novel bioactive peptide, originally isolated from bovine hypothalamus by utilizing an orphan seven-transmembrane-domain receptor expressed in the human pituitary gland. In this paper, we analyzed the tissue distribution of rat and human PrRP and their receptor mRNAs by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Northern blotting. In RT-PCR analysis, rat PrRP receptor mRNA was detected in the central nervous system, and the highest expression was detected in the pituitary gland. In addition, in situ hybridization revealed that rat PrRP receptor mRNA was highly expressed in the anterior lobe of the pituitary. On the other hand, rat PrRP mRNA was most abundantly expressed in the medulla oblongata, while significant levels of expression were widely detected in other tissues. In Northern blot analyses, human PrRP receptor mRNA was detected only in the pituitary gland among tissues examined. Human PrRP mRNA was detected in the medulla oblongata and in the pancreas. In contrast to the pattern of mRNA expression, the highest content of bioactive PrRP was found in the hypothalamus rather than the medulla oblongata in the rat brain, indicating that PrRP mRNA does not always parallel with mature PrRP in tissue distribution. The wide distribution of PrRP and its receptor suggests that they have various functions not only in the pituitary gland but also in the other tissues.

Amino Acid Sequence↗

PubMed1999

Bleomycin stimulates lung fibroblasts to release neutrophil and monocyte chemotactic activity.

We determined whether human lung fibroblasts might release chemotactic activity for neutrophils (NCA) and monocytes (MCA) in response to bleomycin. The human lung fibroblasts supernatant fluids were evaluated for chemotactic activity by a blind well chamber technique. Human lung fibroblasts released NCA and MCA in a dose- and time-dependent manner in response to bleomycin. Checkerboard analysis of supernatant fluids revealed that both NCA and MCA were chemotactic. Partial characterization revealed that NCA was partly heat labile, trypsin sensitive, and predominantly ethyl acetate extractable. In contrast, MCA was partly trypsin sensitive and ethyl acetate extractable. The release of chemotactic activity was inhibited by lipoxygenase inhibitors and cycloheximide. Molecular sieve column chromatography revealed that both NCA and MCA had multiple chemotactic peaks. NCA was inhibited by leukotriene B4 receptor antagonist and anti-IL-8 and G-CSF Abs. MCA was attenuated by leukotriene B4 receptor antagonist, and monocyte chemoattractant protein-1, GM-CSF, and TGF-beta Abs. Leukotriene B4 receptor antagonist and these Abs inhibited the corresponding m.w. chemotactic activity separated by column chromatography. The concentrations of IL-8, G-CSF, monocyte chemoattractant protein-1, GM-CSF, and TGF-beta in the supernatant fluids significantly increased in response to bleomycin. These data suggest that lung fibroblasts may modulate inflammatory cell recruitment into the lung by releasing NCA and MCA in response to bleomycin.

Bleomycin↗

PubMed1999

Metabolic fate of oxidized guanine ribonucleotides in mammalian cells.

8-Oxo-7,8-dihydroguanine- (8-oxoguanine-) containing nucleotides are generated in the cellular nucleotide pool by the action of oxygen radicals produced during normal cellular metabolism. We examined the interconversion and metabolic fate of 8-oxoguanine-containing ribonucleotides in mammalian cells. (1) 8-OxoGTP can be generated not only by direct oxidation of GTP but also by phosphorylation of 8-oxoGDP by nucleotide diphosphate kinase, and the 8-oxoGTP thus formed can serve as a substrate for RNA polymerase II to induce transcription errors. (2) MTH1 protein carrying intrinsic 8-oxo-dGTPase activity has the potential to hydrolyze 8-oxoGTP to 8-oxoGMP, thus preventing misincorporation of 8-oxoguanine into RNA. 8-OxoGMP, the degradation product, cannot be reutilized, since guanylate kinase, which has the potential to phosphorylate both GMP and dGMP, is inactive on 8-oxoGMP. (3) Ribonucleotide reductase, which catalyzes reduction of four naturally occurring ribonucleoside diphosphates, cannot convert 8-oxoguanine-containing ribonucleotide to the deoxyribonucleotide. This step appears to serve as a gatekeeper to prevent formation of mutagenic substrates for DNA synthesis from oxidized ribonucleotides.

Animals↗