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Biomedical subjects

M Taniguchi

Publications and source records attributed to M Taniguchi.

At least 505 records · Page 28Linked to original sources
PubMed1993

Potassium-stimulating mechanism of geranylgeranyl diphosphate synthase of Methanobacterium thermoformicicum SF-4.

The catalytic properties of geranylgeranyl diphosphate (GGPP) synthase [EC 2.5.1.29] purified from Methanobacterium thermoformicicum SF-4 were studied by kinetic procedures. The plots of 1/v versus 1/[S] and inhibition patterns by enzyme reaction products, PPi and GGPP, showed that the GGPP synthase reaction mechanism is an ordered-sequential Bi Bi one. Monovalent cations at low concentration (0.05 M) enhanced the enzyme activity, but at high concentration (0.4 M) they were inhibitory, except for K+. The K+ ion was found to be a modifier forming a parallel reaction pathway and accelerated the binding of substrates to the enzyme, especially the binding of isopentenyl diphosphate (IPP). When substrate concentrations are near the Km values, the rate-limiting step of the GGPP synthase reaction may be the substrate-binding step, probably the IPP-binding step, rather than the conversion step of the enzyme-farnesyl diphosphate-IPP complex to the enzyme-PPi-GGPP complex.

Alkyl and Aryl Transferases↗
PubMed1993

123I-labelled BMIPP fatty acid myocardial scintigraphy in patients with hypertropic cardiomyopathy: SPECT comparison with stress 201Tl.

123I-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) was performed in 17 patients with hypertrophic cardiomyopathy, and was compared with 201Tl exercise stress myocardial perfusion SPECT images. Fourteen patients showed asymmetrical hypertrophy, and three demonstrated apical hypertrophy. SPECT was performed 20 min and 3 h after injection of 111 MBq 123I-BMIPP at rest. Exercise stress 201Tl SPECT was performed at 10 min and 3 h after injection and was compared with BMIPP imaging. In 13 patients BMIPP accumulation in the hypertrophied area in the 20 min image was lower than that of 3 h 201Tl uptake. Interestingly, six patients demonstrated 201Tl redistribution in the region where the uncoupling of BMIPP uptake at 20 min and 201Tl accumulation at 3 h after exercise was observed. These findings suggest that impaired fatty acid metabolism or utilization in hypertrophic myocardium and ischaemia or impaired coronary flow reserve may be one of the causes of the abnormality of fatty acid accumulation.

Adult↗
PubMed1993

Transduction mechanisms in the olfactory and vomeronasal organs of turtles.

It is generally believed that odorants bind to receptor proteins and activate cAMP-dependent channels located in olfactory cilia. In the present paper, we discuss whether or not this mechanism holds for in vivo transduction in the olfactory and vomeronasal organs of a turtle: (1) Elimination of salts from the olfactory epithelium did not affect the responses to odorants; changes in concentration of NaCl or CaCl2 did not affect the olfactory responses. (2) The sensitivity of the vomeronasal system to various general odorants was essentially similar to that of the olfactory system, although the vomeronasal cells have no cilia. Elimination of salts from the surface of the vomeronasal organ, similar to the olfactory system, did not affect responses to odorants. (3) Liposomes having certain lipid compositions responded to odorants with a sensitivity comparable to that in the olfactory system. The liposomes containing phosphatidylserine (PS) exhibited strong responses, especially to fatty acids. (4) Application of PS-containing liposomes to the olfactory epithelium greatly enhanced the responses to fatty acids. The results suggest that the cation channels located at olfactory cilia may not contribute to in vivo olfactory transduction. The results also suggest that lipids in olfactory receptor membranes are important in odor reception.

Animals↗
PubMed1993

Modification of cortical stimulation for motor evoked potentials under general anesthesia: technical description.

This pilot study presents a possible modification of direct cortical electrical stimulation technique for the recording of motor evoked potentials under general anesthesia. The exposed primary motor cortex was stimulated by a short train of anodal rectangular pulses at high frequency (300-500 Hz), while the compound muscle action potentials were recorded from the forearm and hand muscles. When compared with the traditional way of eliciting movement of the extremities by applying a train of pulses at lower frequency (50-60 Hz), muscle responses were obtainable at an intensity of much lower charge. It is suggested that this stimulation achieves a repetitive activation of the corticomotoneuronal tract. Responses could be continuously recorded throughout surgery and seemed to respond to surgical manipulation affecting the motor pathways. This technique seems to be applicable for intraoperative monitoring of motor pathways but requires further optimization of stimulation and recording parameters before wider clinical applications are possible.

Anesthesia, General↗
PubMed1993

The mouse Mel-18 "RING-finger" gene: genomic organization, promoter analysis and chromosomal assignment.

The chromosome gene for mouse Mel-18 (mMel-18) protein has been isolated and characterized. The entire mMel-18 gene is composed of thirteen exons spanning about 15 kilobases, in which the protein is encoded by exons 5-13. The "RING-finger" motif of Mel-18 protein that displays a significant evolutionary resemblance to other RING-finger nuclear proteins is encoded by exons 5 and 6. Exon 13 encodes a C-terminal proline/serine-rich domain that is homologous to some transactivator proteins. Sequence analysis of the 5'-flanking region revealed the presence of potential binding sites for transcription factors such as SP-1, NF-1, NF-kappa B and c-myc/max. At least two major cap sites and three minor cap sites were identified by S1 mapping and primer extension analysis. We propose that the mMel-18 gene is regulated by two different types of promoters, the CAAT-TATA box promoter and the GC-rich TATA-less promoter. The 2.4 kb DNA fragment of the 5'-flanking region exhibited constitutive promoter activity when transfected into L cells. By the in situ hybridization method, the mMel-18 gene was assigned to mouse chromosome 10C3.

Animals↗
PubMed1993

UK-1, a novel cytotoxic metabolite from Streptomyces sp. 517-02. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties.

A new benzoxazole, UK-1, was isolated from the mycelial cake of an actinomycete strain 517-02. Based on morphological, cultural and physiological characteristics, strain 517-02 was seemed to be a close relative of Streptomyces morookaense. UK-1 showed potent cytotoxic activity against B16, HeLa and P388 cells and did not show any antimicrobial activity.

Animals↗
PubMed1993

Analysis of the site on a TNF-alpha molecule which affects type II TNF receptor binding in human cells.

The epitope region on the TNF-alpha molecule recognized by monoclonal antibody (mAb) 3-D-6, which neutralizes the cytotoxic activity on murine LM cells, has been determined as Gly24-Gln-Leu-Gln-Trp-Leu-Asn-Arg31. To examine whether this region participates in TNF receptor binding in human cell lines, four kinds of TNF-alpha mutants (Gln25 --> Glu, Gln27 --> Glu, Leu29 --> Val, and Arg31 --> Ser) were prepared using site-directed mutagenesis. One mutant, mRS31, which has a nonconserative mutation at position 31 (Arg --> Ser), showed markedly reduced binding in U-937 cells and in HL-60 cells compared with the wild-type recombinant TNF-alpha (rTNF-alpha). These two cell lines have been reported to have both type I and type II TNF receptors. mRS31 also showed reduced cytotoxicity on U-937 cells. Another mutant, mLV29, which has a conservative mutation at position 29 (Leu --> Val), showed, to a lesser extent, reduced binding in U-937 cells and HL-60 cells and reduced cytotoxic activity in U-937 cells. However, all four TNF-alpha mutants showed a similar binding in HEp-2 cells and in HeLa cells, which have been reported to have only the type I TNF receptor. These results suggest that Leu29 may be involved in direct contact with the type II receptor and that the nonconservative mutation at position 31 may induce a local conformational change in the site involved in type II TNF receptor binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

[Amlexanox has an acute bronchodilator effect in patients with aspirin-induced asthma (AIA)].

Recently, we have reported that a nebulized solution of sodium cromoglycate (SCG) (Intal), a well known antiallergic agent, has an acute bronchodilator effect in patients with aspirin-induced asthma (AIA). Amlexanox is an antiallergic agent, with a structure similar to that of SCG. Therefore, we investigated the acute bronchodilator effect of amlexanox administered orally to adult asthmatics, focusing on a comparison between AIA and non-AIA patients. Fifteen patients participated, 8 having AIA and 7 non-AIA. After performing spirometry during remission, they were administered either amlexanox or placebo using a randomized double-blind protocol. Spirometry was then performed at 30, 60, 90 min, 2 h, and 3 h after administration. The placebo used was lactose. In the AIA group, FEV1 was significantly improved after administration of amlexanox. However, FEV1 was significantly decreased after placebo administration. On the other hand, in the non-AIA group, FEV1 was not changed after administration of either of the drugs. From these results, we conclude that amlexanox has an acute bronchodilator effect only in AIA patients.

Adult↗
PubMed1993

[A case of sarcoidosis presenting as pulmonary nodules associated with pleural indentation fifteen years after onset].

A 65-year-old woman was admitted to our hospital because of pulmonary nodules, about 3 cm in diameter in the right upper lobe accompanied by pleural indentation, and 5 mm in diameter in the left middle lung field, revealed by chest X-ray. She had no clinical signs or symptoms except achalasia-like discomfort swallowing. Results of physical examinations were within normal limits. A specimen obtained from the nodule in right S2 by transbronchial biopsy showed noncaseating epithelioid granuloma containing asteroid bodies, and negative staining for acid-fast bacilli. No malignant cells were found in the specimen. Bacteriological examination of a bronchial lavage specimen was negative for pyogenic bacteria, mycobacteria and fungi. A PPD skin test was negative. BALF revealed an increase of lymphocytes and elevation of CD4/CD8 ratio. Fifteen years previously, the patient had been diagnosed as having sarcoidosis by scalene node biopsy, and had been treated with steroid therapy. Pulmonary nodules associated with pleural indentation in sarcoidosis is relatively rare, and is usually due to malignancy such as lung cancer. This possibility was ruled out clinically in the present case. Therefore, it was concluded that the pulmonary nodules in this case were due to the sarcoidosis itself.

Age of Onset↗
PubMed1993

[Two cases of acute eosinophilic pneumonia with precipitating antibody against Trichosporon cutaneum and Trichoderma viride].

Two cases of acute eosinophilic pneumonia are described. The patients presented with an acute febrile illness, dry cough, severe hypoxemia and diffuse pulmonary infiltrates. Total cell count and the number of eosinophils were increased in bronchoalveolar lavage fluid. The TBLB specimen showed eosinophilic infiltration of alveolar walls and spaces. Precipitating antibodies against Trichosporon cutaneum and Trichoderma viride were noted in the patients' sera, and environmental provocation tests gave positive results. The clinical features of acute eosinophilic pneumonia resemble those of summer type hypersensitivity pneumonitis. From these results, we consider that there is a certain degree of overlap between the two diseases.

Adult↗
PubMed1993

[Congenital extradural cyst causing a 30-year history of myelopathy with long-term remission].

We reported a peculiar case of a patient with a thoracic extradural cyst, who had a 30-year history of thoracic-myelopathy with a very long-term remission. A 42-year-old male was admitted to our hospital complaining of gait disturbance and hypesthesia of his bilateral lower limbs. Neurological examination revealed that he had spastic paraparesis and hypesthesia of all sensory modalities below Th11/12 dermatomes. Investigation of his past history disclosed that he had experienced gait disturbance due to paraplegia 29 years previously and had been able to move only with the aid of wheel-chairs. However these signs had resolved themselves gradually in a period of 3 years, and after that he had been able to live almost without any neurological handicaps until the recent appearance of weakness in both of his legs. Neuroradiological study revealed that plain X-Ps of the thoracic spine showed thinning of the pedicles and widening of the interpedicular distances between Th4-Th7 vertebrae. The old iodine contrast media injected 29 years previously for myelography in an other hospital was also observed. MRI showed a dorsal cystic mass compressing the thoracic spinal cord and subarachnoid space. Myelography showed also that the spinal cord and subarachnoid space were compressed anteriorly between the level of Th3 to Th7 by the dorsal mass. CT myelography disclosed that soon after the injection of contrast media a small part of the cyst was visualized as having direct communication with the subarachnoid space. The contrast media penetrated the major part of the cyst only 19 hours after its injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Assessment of congenital heart disease by a thallium-201 SPECT study in children: accuracy of estimated right to left ventricular pressure ratio].

The characteristics of correlation between the right-to-left ventricular systolic pressure ratios (RVp/LVp) and the thallium-201 right-to-left ventricular (201Tl R/L) count ratios was investigated in children with various congenital heart diseases. High-resolution three-headed SPECT system equipped with either parallel-hole or fan-beam collimators was used. In a total of 102 patients, the correlation between RVp/LVp and 201Tl R/L average count ratios was good in both planar (r = 0.89, p = 0.0001) and SPECT studies (r = 0.80, p = 0.0001). Quantitative analysis of myocardial uptake by SPECT demonstrated the characteristic pattern of each disease as well as the differences in the right ventricular overload types. When the linear regression analysis was performed in each heart disease, ventricular septal defect showed most excellent correlation. Complex heart anomalies also showed positive correlation (r = 0.51, p = 0.05) with RVp/LVp, and it can be used to estimate right ventricular pressure. After surgical treatment of tetralogy of Fallot and pulmonary stenosis, the decrease of 201Tl R/L count ratio was in accordance with improvement of right ventricular overload. We conclude that 201Tl SPECT study can be a good indicator for estimation of right ventricular pressure.

Adolescent↗
PubMed1993

cDNA cloning of mouse ret proto-oncogene and its sequence similarity to the cadherin superfamily.

We report the nucleotide sequence of the mouse ret proto-oncogene (proto-ret) and the deduced amino acid sequence. It encodes a transmembrane tyrosine kinase of 1115 amino acids that shows 83% homology with the human proto-Ret protein. The amino acid sequence revealed that the structures of the extracellular domain as well as the tyrosine kinase domain are similar in human and mouse proto-Ret proteins. Interestingly, the extracellular domains of both human and mouse proto-Ret proteins contain a cadherin-related sequence that is known to be important for Ca(2+)-dependent homophilic binding of the cadherins. When we examined transcription of the proto-ret gene in a variety of mouse tissues, it was detected in lymph nodes of C3H/HeJ-gld/gld mice and in normal mouse spinal cord. Furthermore, its transcription was found in the Neuro-2a mouse neuroblastoma cell line but not in 13 other rodent cell lines surveyed. Western blot analysis showed that proto-Ret proteins are expressed as 140-kDa and 160-kDa glycoproteins in Neuro-2a cells.

Amino Acid Sequence↗
PubMed1993

[Clinical features and prognosis of Churg-Strauss syndrome].

We studied the clinical features and prognosis of 11 patients with Churg-Strauss syndrome (CSS). Subjects included 1 man and 10 women with a mean age of 56.3 years. All subjects had a history of bronchial asthma prior to the onset of CSS. It was noted that the age of onset of bronchial asthma was high, and most of the patients had suffered from frequent and severe asthmatic attacks during the periods preceding the vasculitis. Skin tests and IgE RAST revealed that less than half of the subjects were atopic. Therefore it is considered that asthmatics with late onset and severe symptoms have a high risk for CSS, and poor control of asthmatic symptoms may contribute to the onset of the vasculitis. Eleven of 12 cases including 1 patient with a relapse were treated with PSL alone (9 cases) or PSL plus cyclophosphamide (2 cases). Three patients died of heart failure or central nerve involvement. Vasculitis was ameliorated in the other cases (75%). Seven patients received maintenance therapy with low-dose of PSL (5 cases) or cyclophosphamide (2 case). None suffered from relapse of vasculitis during maintenance therapy. Discontinuation of therapy in five cases resulted in a relapse in only one case 62 months after the cessation of low-dose PSL. Although maintenance therapy appears to be useful in some CSS patients, the significance and indications for maintenance therapy should be further clarified.

Adult↗
PubMed1993

[A case of streptomycin-induced lupus].

A case of streptomycin-induced lupus occurring in a 48-year-old female is presented. She was admitted to our hospital in July 1990, complaining of productive cough and general fatigue. A chest roentgenogram showed cavitary lesions and infiltrative shadows in the bilateral upper and middle lung fields and a sputum smear tested positive for acid-fast bacilli. She was diagnosed as lung tuberculosis and antituberculous therapy with isoniazid, rifampicin and streptomycin was started. Ten days after starting the treatment, she began to complain of high fever and erythema on her face and forearms. Blood cell count revealed leucopenia. The antinuclear antibody and antihistone antibody were positive. The improvement of clinical findings and the lowering of antinuclear antibody titer seen after stopping streptomycin confirmed the diagnosis as streptomycin-induced lupus. Streptomycin-induced lupus is very rare.

Female↗
PubMed1992

Malignant fibrous histiocytoma coexistent with mucinous cystadenoma of the pancreas.

A patient with malignant fibrous histiocytoma (MFH) coexistent with mucinous cystadenoma of the pancreas is reported. Primary MFH of the pancreas is rare, with only six patients reported in the world medical literature. A patient with MFH coexistent with a pancreatic mucinous epithelial tumor has not been reported previously, although two patients with pseudosarcomatous tumor associated with mucinous cystadenocarcinoma of the pancreas have been reported. Mural nodules of similar histologic appearance have been reported in ovarian mucinous tumors. The authors believe this to be the first report of the occurrence of MFH in mucinous cystadenoma of the pancreas.

Adult↗