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Biomedical subjects

N Mutoh

Publications and source records attributed to N Mutoh.

At least 37 records · Page 2Linked to original sources
PubMed1993

Fate of cadmium bound to phytochelatin in rats.

The fate cadmium(Cd) bound to phytochelatin [PC, (gamma-Glu-Cys)n-Gly)] was studied in rats using synthesized 109Cd-PC. Less Cd was absorbed through the digestive tracts than CdCl2, but the ratio of renal Cd to hepatic Cd was higher. After parenteral administration of Cd-PC, Cd was distributed mainly in the liver, kidney, small intestine and pancreas. More Cd was found in the kidney than the liver after Cd-PC (n = 5) administration. Most of the Cd was bound to the high molecular weight fraction in the hepatic cytosol 0.5 hr after administration and moved to the metallothionein fraction at 6 hr. The tissue distribution of Cd was not affected even when free PC (n = 5) was administered 3 hr after or before Cd injection. The distribution in the kidney increased only in the case of the simultaneous administration of Cd with PC. These findings show that the absorbance of Cd bound to PC from the alimentary tract is lower than that of CdCl2 although absorbed Cd is distributed to the kidney more than CdCl2, and Cd is liberated from PC soon after uptake by the cells.

Absorption↗
PubMed1992

Study of experimental cervical spondylotic myelopathy.

UNLABELLED: Most cervical spondylotic myelopathy cases show insidious onset. Experimental cervical spondylotic myelopathy models were made using cats to analyze advancing patterns of myelopathy in the spinal cord and to identify the most responsible factor. Spinal cord compression was applied anteriorly using one screw through the C5 vertebral body or three screws through the C4, C5, and C6 vertebral bodies. Every few weeks, the screws were turned approximately 1 mm at a time up to approximately 50% of the spinal canal. At more than 6 months after final compression, limb function and evoked spinal cord potentials were evaluated. Thereafter, histologic examinations were performed. THE RESULTS: the single compression group showed normal limb function, but the multiple compression group showed sluggish gait. Histologically, mild neuronal decrease in the gray matter was noticeable in the single compression group. Conversely, the multiple compression group showed severe changes in the gray matter and significant changes in the posterior and anterior columns. There was a correlation between the evoked spinal cord potentials and histologic changes. It was clear that multiple compressions to the spinal cord caused more severe deterioration functionally and electrophysiologically as well as histologically than a single compression.

Animals↗
PubMed1992

Sporeamicin A, a new macrolide antibiotic. I. Taxonomy, fermentation, isolation and characterization.

Sporeamicin A, a novel antibiotic, was isolated from the culture filtrate of an actinomycete. The producing organism, strain L53-18, was taxonomically assigned as a species of the genus Saccaropolyspora. The antibiotic was extracted with chloroform and was then purified by crystallization. It was obtained as colorless prisms from ethanolic solutions. Sporeamicin A exhibited a strong UV absorption peak at 276 nm. The molecular formula of sporeamicin A was determined to be C37H63NO12.

Anti-Bacterial Agents↗
PubMed1992

Sporeamicin A, a new macrolide antibiotic. III. Biological properties.

Sporeamicin A is a new erythromycin-type antibiotic isolated from a species of Saccharopolyspora. It was active in vitro against a wide variety of Gram-positive bacteria. In vitro studies indicated that the sporeamicin A was stable in the presence of human serum, although it was bound to serum proteins. Sporeamicin A was effective in the mouse protection test against Staphylococcus aureus, Streptococcus pyogenes and Streptococcus pneumoniae. Sporeamicin A attained higher plasma and tissue levels in the rat than did erythromycin stearate.

Animals↗
PubMed1992

[Image analysis of the inner ear with CT and MR imaging: pre-operative assessment for cochlear implant surgery].

Recent progress in magnetic resonance imaging (MRI) has made it possible to obtain detailed images of the inner ear by delineating the lymphatic fluid within the labyrinth. We analyzed CT scans and MR images in 70 ears manifesting profound deafness owing to inner ear lesions and compared their detective ability for inner ear lesions. The following results were obtained. 1) CT scan examination showed slight to extensive ossification of the labyrinth in six ears (9%), whereas MRI examination revealed low to absent signal intensity of the inner ear in nine ears (13%). Therefore, it was concluded that MRI is more sensitive in detecting abnormalities of the inner ear than CT scan. 2) MRI provided useful information as to whether the cochlear turn is filled with lymphatic fluid or obstructed. This point was one of the greatest advantages of MRI over CT scan. 3) Abnormal findings in either or both the CT scan and the MRI were detected in suppurative labyrinthitis occurring secondary to chronic otitis media, bacterial meningitis and in inner ear trauma. However, such abnormal findings were not detected in patients with idiopathic progressive sensorineural hearing loss, ototoxicity or sudden deafness. These findings should be taken into consideration in pre-operative assessment of cochlear implant candidates.

Adult↗
PubMed1991

Cloning and sequencing of the gene encoding the large subunit of glutathione synthetase of Schizosaccharomyces pombe.

The gene for the large subunit of glutathione synthetase (EC 6.3.2.3) of Schizosaccharomyces pombe was cloned from a S. pombe genomic DNA library by complementation of cadmium hypersensitivity of a glutathione synthetase deficient mutant of S. pombe. A long open reading frame was found in the cloned DNA sequence. Amino acid sequence predicted from the long open reading frame coincided with amino acid sequences of peptides obtained by V8 protease digestion of the large subunit of the purified glutathione synthetase. The glutathione synthetase deficient mutant which harbored plasmids containing the glutathione synthetase large subunit gene exhibited glutathione synthetase activity higher than the activity in the wild type strain, though the plasmid did not contain the gene for the small subunit of the enzyme.

Amino Acid Sequence↗
PubMed1991

Tetramethylthiuram disulfide or dimethyldithiocarbamate induces the synthesis of cadystins, heavy metal chelating peptides, in Schizosaccharomyces pombe.

Tetramethylthiuram disulfide (TMTD) or dimethyldithiocarbamate (DMDTC) induces the synthesis of cadystins, a family of heavy metal chelating isopeptides with the formula (gamma-Glu-Cys)n-Gly (n = 2,3,4,...), in the fission yeast Schizosaccharomyces pombe. Amount of cadystins synthesized in TMTD or DMDTC treated cells is less than that synthesized in CdCl2 treated cells but much more than that synthesized in ZnCl2 or CuSO4 treated cells.

Amino Acids↗
PubMed1991

Desmoplastic fibroma in the thoracic spine.

Desmoplastic fibroma of the spine is an extremely rare, benign tumor. So far, only 7 cases have been reported in the world. We have treated 1 case of desmoplastic fibroma in the thoracic spine. Due to insufficient removal of the tumor, local recurrence was observed, and a second surgery posteriorly and anteriorly was performed for complete removal 8 years following the first operation. After resection of the tumor, Luque instrumentation was used to reconstruct the destroyed spine. At present, 7 years after the second operation, there are no signs or symptoms. Therefore, complete resection of the tumor is most important in the treatment, and rigid spinal instrumentation and bone grafts must be used after removing the tumor in spine cases.

Adult↗
PubMed1991

Intraoperative monitoring for tethered spinal cord syndrome.

Functions of the lower extremities and bowel and bladder must be monitored during releasing surgery for tethered spinal cord syndrome, because neural elements are embedded in lipoma or anomalous tissues. Evoked muscle action potentials of the external anal sphincter muscle, external urethral sphincter muscle, and lower extremity muscles can indicate promptly whether or not neural elements are involved before the surgeon releases or cuts the tissue for cord release. It is also important to monitor vesical pressure because of different types of innervation from the external urethral and anal sphincters, in spite of slow reaction times of vesical pressure elevation. Evoked muscle action potentials indicate only motor function; therefore, it is more appropriate to record evoked spinal cord potentials from the spinal cord above a lumbosacral operative field, because sensory function can also be monitored. Evoked muscle action potentials are an easy and extremely sensitive monitoring system; nevertheless, monitoring of vesical pressure and evoked spinal cord potentials should also be done to achieve optimum monitoring. For the past 5 years, 10 patients have undergone cord-release surgery with such a monitoring system, and the results indicate no exacerbating case.

Adolescent↗
PubMed1989

Effect of pirenzepine on aminopyrine uptake by isolated guinea pig parietal cells.

The inhibitory action of pirenzepine on acid secretion of isolated guinea pig parietal cells was investigated by the aminopyrine method. Pirenzepine markedly inhibited acid secretion of isolated parietal cells induced by carbachol in a dose-dependent manner but showed no inhibition on acid secretion stimulated by histamine. These results may suggest a direct action of pirenzepine on muscarinic receptors in parietal cells.

Aminopyrine↗
PubMed1988

Isolation of mutants of Schizosaccharomyces pombe unable to synthesize cadystin, small cadmium-binding peptides.

Schizosaccharomyces pombe synthesize small cadmium-binding peptides cadystin, structure of which is (gamma-Glu-Cys)n-Gly, in response to cadmium. Mutants unable to synthesize cadystin were found in the mutants hypersensitive to cadmium. Some of them lack activity of either gamma-glutamylcysteine synthetase (EC 6.3.2.2) or glutathione synthetase (EC 6.3.2.3), enzyme involved in glutathione biosynthesis. Some mutants have the same activity levels of these enzymes as wild type has. These results indicate that some steps of cadystin biosynthesis are catalyzed by the enzymes catalyzing glutathione biosynthesis.

Cadmium↗
PubMed1988

Cloning of the C-terminal cytoplasmic fragment of the tar protein and effects of the fragment on chemotaxis of Escherichia coli.

A gene encoding only the C-terminal portion of the receptor-transducer protein Tar of Escherichia coli was constructed. The gene product was detected and localized in the cytoplasmic fraction of the cell by immunoblotting with anti-Tar antibodies. The C-terminal fragments from wild-type and mutant tar genes were characterized in vivo. The C-terminal fragment generated from tar-526, a mutation that results in a dominant "tumble" phenotype, was found to be deamidated and methylated by the CheB and CheR proteins, respectively. The C-terminal fragment derived from a wild-type gene was poorly deamidated, and the C-terminal fragment derived from tar-529, a dominant mutant with a "smooth swimming" phenotype, was not apparently modified. Cells carrying the C-terminal fragment with the tar-526 mutation as the sole receptor-transducer protein showed a high frequency of tumbling and chemotaxis responses to changes in intracellular pH. These results suggest that the cytoplasmic C-terminal fragment of Tar retains some of the functions of the whole protein in vivo.

Aspartic Acid↗
PubMed1986

Nucleotide sequence corresponding to five chemotaxis genes in Escherichia coli.

The nucleotide sequence of DNA which contains five chemotaxis-related genes of Escherichia coli, cheW, cheR, cheB, cheY, and cheZ, and part of the cheA gene was determined. Molecular weights of the polypeptides encoded by these genes were calculated from translated amino acid sequences, and they were 18,100 for cheW, 32,700 for cheR, 37,500 for cheB, 14,100 for cheY, and 24,000 for cheZ. Nucleotide sequences which could act as ribosome-binding sites were found in the upstream region of each gene. After the termination codon of the cheW gene, a typical rho-independent transcription termination signal was observed. There are no other open reading frames long enough to encode polypeptides in this region except those which code for the two previously reported genes tar and tap.

Base Sequence↗