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Biomedical subjects

A Nakamura

Publications and source records attributed to A Nakamura.

At least 361 records · Page 20Linked to original sources
PubMed1997

[A case report of surgical treatment for aneurysm of the brachiocephalic artery associated with tracheal stenosis].

A 76-year-old woman, diagnosed with aneurysm of the brachiocephalic artery thirteen years ago, encountered tracheostenosis due to tracheal compression induced by an increase in size of the aneurysm. Complete aneurysmectomy with graft replacement under cardiopulmonary bypass failed to improve the bronchostenosis. This was attributed to tracheomalacia developed as a result of malatic tracheal cartilages. On day 14 post operation, external fixation of the trachea with an autografted costa relieved her condition markedly. Aneurysm of the brachiocephalic artery is rare and asymptomatical. As such, the present case report suggests that patients with such a aneurysm should be promptly operated to present both the risk of arterial rupture and unfavorable compression of adjacent organs.

Aged↗
PubMed1997

[A case of corticobasal degeneration presenting with primary progressive aphasia].

We report a 64-year-old right-handed woman whose initial symptom was slowly progressive aphasia without generalized dementia and who was subsequently diagnosed as having corticobasal degeneration (CBD). Neurological examination revealed disturbed vertical gaze, dysarthria, rigidity of the right upper extremity, and bilateral instinctive grasp reaction. Neuropsychological assessment disclosed Broca's aphasia, buccofacial apraxia, and memory disturbance. MRI of the brain showed atrophy of the frontotemporal lobes, which was more severe on the left than on the right, especially the left inferior frontal gyrus. In most reported cases of CBD, the initial symptom is motor dysfunction of the unilateral upper or lower extremity. However, we should be cautious that among cases with CBD, there have been rare cases that begin with progressive aphasia alone. In our case, the atrophied region of the cerebral cortex was most severe around the left inferior frontal gyrus. In a few reported cases with the initial symptom of aphasia, the atrophied region corresponded considerably to the type of the aphasia. On the other hand, in those whose initial symptom was mainly motor dysfunction of the unilateral extremity, the atrophied region was remarkable in the posterior part of the frontal lobe and parietal lobe. Therefore, we suggest that in CBD the distribution of the cerebral cortical lesions differs in accordance with whether the initial symptom is motor disturbance or aphasia, and that the type of aphasia corresponds to the location of the cortical lesion.

Aphasia, Broca↗
PubMed1997

[Two clinical case of spontaneous hemopneumothorax caused by aberrant vessel].

Spontaneous hemopneumothorax is a rare disease and intrathoracic bleeding reportedly occurs in the detached region of adhesive parietal pleura, aberrant vessel and cystic wall. We experienced two cases of bleeding most likely from the aberrant vessel. One patient was a 25-year-old male who had severe chest pain with dyspnea for four days. Chest X-ray revealed left pneumothorax and mediastinal shift to the right. Approximately 1500 ml of blood was aspirated from the left thoracic cavity. Since bleeding continued, emergency thoracotomy was performed. A restiform structure was noted in the bulla at the apex of the lung and the stump of the structure was considered as the source of bleeding. The other patient was a 29-year-old male who underwent emergency operation 16 hours after the massive bleeding amounting to 1800 ml. At the thoracotomy, a ruptured bulla at the apex of the collapsed lung with restiform structure was encountered. The bleeding point in the stump of the structure was ligated and the ruptured bulla was resected. In the histological study of these patients, an aberrant blood vessel was revealed in the restiform structure, which suggests the etiology of the bleeding. Their postoperative course was uneventful and had no symptom at the discharge. In the management of spontaneous hemopneumothorax, early thoracotomy should be the first consideration taking into account the massive bleeding from the aberrant vessel as in the cases.

Adult↗
PubMed1997

[Combination effect of fosfomycin to beta-lactam, aminoglycoside, and macrolide antibiotics against clinical isolates of Klebsiella pneumoniae].

It is well known that fosfomycin (FOM) shows the combination effects with some other antibiotics. Suck effects have not been known against Klebsiella pneumoniae, however. In this report, combination effects of FOM with beta-lactam, aminoglycoside, and macrolide antibiotics were investigated against clinical isolates of both FOM-susceptible and resistant Klebsiella pneumoniae. FOM had synergistic activities with beta-lactams such as ampicillin (ABPC) and cefminox (CMNX), and macrolide antibiotics as erythromycin (EM) and midecamycin (MDM) against all strains tested. Among beta-lactams, penicillin V showed synergistic actions against FOM-susceptible strain of Tf341A and additive actions against FOM-resistant 3 strains with FOM. Pheneticillin was synergistic with FOM against FOM-highly susceptible strain Tf341A and the additive or nearly synergistic effects against other strains. FOM with amoxicillin was synergistic against Tf341A, and FOM-resistant strain of Tf170B and additive against other strains. While the activities of combination of FOM with kanamycin or dibekacin against FOM-susceptible 2 strains were additive, those with amikacin were synergistic. Five different aminoglycosides tested showed antagonistic activities with FOM against 3 FOM-resistant strains. From these results, FOM appears to be clinically useful in treating FOM-susceptible and resistant strains of Klebsiella pneumoniae in combination of 4 antibiotics such as ABPC, CMNX, EM, and MDM.

Aminoglycosides↗
PubMed1997

Increased portal tract infiltration of mast cells and eosinophils in primary biliary cirrhosis.

OBJECTIVES: Although recent reports demonstrate that eosinophilia is a distinctive feature of early stage primary biliary cirrhosis (PBC), the pathogenesis of this eosinophilia remains unknown. Clinical and experimental data suggest potential mast cell activation in cholestatic liver diseases. Because mast cell-derived mediators could induce eosinophil chemotaxis and activation, we hypothesized that mast cell activation may play a role in the pathogenesis of eosinophilia in PBC. Thus, as the first step in examining a possible link between mast cell activation and eosinophilia in PBC, we quantified the infiltration of mast cells and eosinophils in the livers of patients with PBC. METHODS: The study population consisted of 11 patients with stage I or stage II PBC and 11 patients with chronic viral hepatitis. Mast cells and eosinophils were identified by immunohistochemistry using monoclonal antibodies against mast cell tryptase (AA1) and eosinophilic cationic protein (EG2), respectively. Cell infiltration in the portal tract was quantitated morphometrically. RESULTS: When compared with patients with chronic viral hepatitis, patients with PBC showed significantly increased portal infiltration with mast cells (140 +/- 25 vs 72 +/- 10 cells/mm2 [mean +/- SEM, p < 0.05]) and eosinophils (76 +/- 19 vs 32 +/- 9 cells/mm2 [p < 0.05]). Numbers of portal mast cells correlated with numbers of eosinophils in patients with PBC (r = 0.60, p < 0.05) but not in patients with chronic hepatitis (r = 0.34, p = 0.47). CONCLUSION: Concomitant increases in mast cell and eosinophil infiltration in the portal tract suggest a role for mast cell activation in the pathogenesis of eosinophilia in PBC.

Antibodies, Monoclonal↗
PubMed1997

[Correlation of cardiac muscle involvement and the dystrophin gene abnormality in Becker muscular dystrophy].

Cardiomyopathy is one of the most important clinical manifestations in Becker muscular dystrophy (BMD), but the severity of cardiac involvement is not usually related to that of skeletal muscle disability in this disease. In general, BMD patients who carry the mutations in the 5' end of the dystrophin gene tend to show severe cardiac dysfunction compared with skeletal myopathy, and these mutations may be responsible for more selective involvement of dystrophin appearance in the myocardium. In this article, we review the causative relationship of the variable clinical pictures and the dystrophin gene abnormalities in BMD patients, focusing on the severity of cardiac disorder.

Cardiomyopathy, Dilated↗
PubMed1997

[A case of pneumoconiosis (welder's lung) suspected to be lung cancer].

A 60-year-old man, employed as a welder for 25 years, was admitted with an abnormal shadow on chest X-ray. An ill-defined and solitary mass shadow 3 cm in diameter was subsequently detected in the left upper lung field. The mass shadow exhibited high attenuation on chest CT scan. Transbronchial lung biopsy (TBLB) revealed an organized lesion possessing a large quantity of iron. Although pneumoconiosis was suspected, the possibility of lung cancer could not be dismissed. Pneumoconiosis (welder's lung) was diagnosed after thoracotomy and examination of the resected mass. Pneumoconiosis (welder's lung) rarely presents as a solitary mass lesion.

Diagnosis, Differential↗
PubMed1997

[Cytotoxicity of chemicals used in household products: estimation of eye irritating potency of 25 chemicals tested during 1991-1996].

Cytotoxicity potential of chemicals was evaluated by determining the concentrations inducing 50% reduction of neutral red (NR) uptake into Chinese hamster fibroblast V79 cells compared with control culture (IC50). The results of cytotoxicity test for surfactants with the data produced by the in vivo Draize eye and skin irritation test were compared. There was a good correlation between cytotoxicity and eye irritation score obtained from the Draize test. In contrast, no correlation was observed between Draize skin irritation score and cytotoxic potential of chemicals. Therefore, the NR cytotoxicity test was regarded as a possible in vitro model for predicting eye irritation. Based on the IC50 values in the NR cytotoxicity test, the eye irritation classification (weak, moderate and strong) for each chemical used in household products has been established. We evaluated the cytotoxicity of 25 chemicals used for antimicrobial, rubber accelerator, rubber antioxidant, ultraviolet absorber etc. in household products, and estimated the eye irritating potency of these test chemicals according to the criterion.

Animals↗
PubMed1997

[Antimicrobial activities of roxithromycin against recently obtained clinical isolates].

The purpose of our investigation was to monitor current trends in the susceptibility patterns of clinical bacterial isolates to roxithromycin (RXM). We measured the MICs of macrolide antibiotics, such as RXM, erythromycin (EM), clarithromycin (CAM), rokitamycin (RKM) and midecamycin (MDM), and other classes of antibacterial compounds against various clinical isolates at seven institutions between October and December in 1994 and 1995. RXM had excellent antibacterial activities for S. pyogenes, S. agalactiae, M. (B.) catarrhalis and methicillin sensitive S. aureus. Against methicillin sensitive S. epidermidis, RXM activity was fairly good but about 20% of the strains had MIC > or = 128 micrograms/ml. The activity against S. pneumoniae was not so potent and similar to activities of EM, CAM, MDM, and clindamycin. The vast majority of methicillin resistant S. aureus and S. epidermidis were also resistant to macrolide antibiotics and other classes of compounds tested. In conclusion, RXM is an unique macrolide antibiotic by retaining potent activity against S. pyogenes, S. agalactiae, S. aureus except MRSA, M. (B.) catarrhalis and M. pneumoniae.

Amoxicillin↗
PubMed1996

Requirement for a noncoding RNA in Drosophila polar granules for germ cell establishment.

In Drosophila embryos, germ cell formation is induced by specialized cytoplasm at the posterior of the egg, the pole plasm. Pole plasm contains polar granules, organelles in which maternally produced molecules required for germ cell formation are assembled. An untranslatable RNA, called Polar granule component (Pgc), was identified and found to be localized in polar granules. Most pole cells in embryos produced by transgenic females expressing antisense Pgc RNA failed to complete migration and to populate the embryonic gonads, and females that developed from these embryos often had agametic ovaries. These results support an essential role for Pgc RNA in germline development.

Animals↗
PubMed1996

Analysis of Cre1 binding sites in the Trichoderma reesei cbh1 upstream region.

A 1.5-kb XbaI-SacII fragment containing the upstream region of the Trichoderma reesei cellobiohydrolase I gene (cbh1) has been sequenced. The 1.5-kb fragment contains eight 6-bp sites having an identical or similar sequence to the consensus sequence for binding a catabolite repressor, Aspergillus nidulans CreA. Results of binding assays with the maltose-binding protein::Cre1(10-131) fusion protein (Cre1 is a catabolite repressor of T. reesei) and the cbh1 upstream region revealed that a 504-bp XbaI-NspV fragment (nucleotide position -1496 to -993) bearing three 6-bp sites, A1, A2, and A3, and a 356-bp NspV-MunI fragment (nucleotide position -994 to -639) bearing three 6-bp sites, B1, B2, and B3, were shifted in the electrophoretic mobility shift assay. DNase I footprinting experiments showed that the 6-bp sites A2, B1, B2, and B3 were protected from DNase I digestion.

Base Sequence↗
PubMed1996

X-ray structure of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011. Comparison of two independent molecules at 1.8 A resolution.

Cyclodextrin glucanotransferase (CGTase) is an enzyme which produces cyclodextrins by the degradation of starch. The enzyme from alkalophilic Bacillus sp. 1011, consisting of 686 amino acid residues, was crystallized from the solution containing 20% PEG 3000 and 20% 2-propanol at pH 5.6 adjusted with citrate buffer. The space group was P1 and the unit cell contained two molecules (V(m) = 2.41 A(3) Da(-1)). The structure was solved by the molecular replacement method and refined to a conventional R value of 0.161 (R(free) = 0.211) for the reflections in the resolution range 1.8-10 A by energy minimization combined with simulated annealing. The molecule consists of five domains, designated A-E, and its backbone structure is similar to the structure of other bacterial CGTases. The molecule has two calcium binding sites where calcium ions are coordinated by seven ligands, forming a distorted pentagonal bipyramid. The two independent molecules are related by a pseudotwofold symmetry and are superimposed with an r.m.s. deviation value of 0.32 A for equivalent C(alpha) atoms. Comparison of these molecules indicated the relatively large mobility of domains C and E with respect to domain A. The active site is filled with water molecules forming a hydrogen-bond network with polar side-chain groups. Two water molecules commonly found in the active center of both molecules link to several catalytically important residues by hydrogen bonds and participate in maintaining a similar orientation of side chains in the two independent molecules.

Journal Article↗
PubMed1996

Cloning, sequencing, and expression of the cellulase genes of Humicola grisea var. thermoidea.

We have cloned an endoglucanase (EGI) gene and a cellobiohydrolase (CBHI) gene of Humicola grisea var. thermoidea using a portion of the Trichoderma reesei endoglucanase I gene as a probe, and determined their nucleotide sequences. The deduced amino acid sequence of EGI was 435 amino acids in length and the coding region was interrupted by an intron. The EGI lacks a hinge region and a cellulose-binding domain. The deduced amino acid sequence of CBHI was identical to the H. grisea CBHI previously reported, with the exception of three amino acids. The H. grisea EGI and CBHI show 39.8% and 37.7% identity with T. reesei EGI, respectively. In addition to TATA box and CAAT motifs, putative CREA binding sites were observed in the 5' upstream regions of both genes. The cloned cellulase genes were expressed in Aspergillus oryzae and the gene products were purified. The optimal temperatures of CBHI and EGI were 60 degrees C and 55-60 degrees C, respectively. The optimal pHs of these enzymes were 5.0. CBHI and EGI had distinct substrate specificities: CBHI showed high activity toward Avicel, whereas EGI showed high activity toward carboxymethyl cellulose (CMC).

Amino Acid Sequence↗
PubMed1996

Effects of tactile interference stimulation on somatosensory evoked magnetic fields.

Tactile stimulation of the hand interferes with somatosensory evoked brain responses following electrical median nerve stimulation. This effect was studied in eight normal subjects by magnetonecephalography (MEG). When stimulation was applied to the hand ipsilateral to the stimulated nerve, only the third response (3M) was enhanced in five subjects, but other responses were attenuated in all subjects. These interference effects were probably due to interactions in areas 3b and 1. After stimulation of the contralateral hand, only the second response (2M) was enhanced in six subjects. This effect was probably due to the intracerebral interactions mediated through the corpus callosum.

Adult↗
PubMed1996

Two-domain haemoglobin of the blood clam Barbatia lima resulted from the recent gene duplication of the single-domain delta chain.

The blood clam Barbatia lima subsp. from Amami-Oshima, Japan, expresses three types of haemoglobins in erythrocytes: a tetramer (alpha 2 beta 2), a homodimer (delta 2) and a polymer consisting of two kinds of chains, a 34 kDa two-domain (2D) globin and a delta chain. This is in sharp contrast to the congeneric clams B. reeveana (a North American species) and B. lima from Kochi, Japan, each containing a tetramer and a polymer consisting of the 2D globin, but not the delta chain. We have determined the cDNA-derived amino acid sequences of all four chains, alpha (163 residues), beta (155 residues), delta (152 residues) and 2D (308 residues) of B. lima (Amami-Oshima). The alpha chain has an extremely long N-terminal extension of 20 residues that may form a 'pre-A helix', and this makes the alpha chain the longest known globin. B. lima alpha and beta chains show about 50% sequence identity with the alpha and beta chains, respectively, of tetrameric haemoglobin from a related clam, Anadara trapezia. The B. lima homodimeric delta chain shows 71-74% identity with each of the two domains of the 2D chain, but only 39% identity with the homodimeric gamma chain of Anadara. In addition, the alignment of amino acid sequences of the delta chain and the two domains of the 2D chain revealed that the delta chain lacks one amino acid (Lys) at the C-terminus, suggesting that the C-terminal Lys (codon AAA or AAG) of the two domains of 2D chain could result from the stop codon TAA in the delta chain by nucleotide substitutions. These results, together with the fact that the delta and 2D chains form a polymeric haemoglobin, indicates that the delta chain is the ancestral single-domain globin for the 2D globin. The delta chain is expressed only in B. lima (Amami-Oshima), and appears to be a relic of molecular evolution.

Amino Acid Sequence↗