PubMed Health⌕ Search

Biomedical subjects

M Wachi

Publications and source records attributed to M Wachi.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Epilepsy surgery for focal cortical dysplasia and dysembryoplastic neuroepithelial tumor].

We studied six patients with focal cortical dysplasia (CD) and four patients with dysembryoplastic neuroepithelial tumor (DNT) who had surgical resection for medically intractable epilepsy. In all CD patients, ictal single photon emission computed tomography (SPECT) using 99mTc-ECD revealed hyperperfusion in the regions where magnetic resonance (MR) imaging showed CD abnormalities. Interictal epileptiform activity and ictal seizure onset on electrocorticography using subdural strip or grid electrodes were demonstrated in the CD itself. In contrast, in all DNT patients, interictal SPECT disclosed hypoperfusion in the area of the lesions. Ictal SPECT in one DNT patient disclosed hyperperfusion in the superior area of the region where MR imaging showed cystic abnormalities. Interictal spiking in all DNT patients and ictal seizure onset in two DNT patients were demonstrated not in the lesions themselves but in the distinct zone from the region of the tumor-involved brain. All CD patients who underwent lesionectomy became seizure-free with a mean follow-up period of 33.5 months. All DNT patients who underwent lesionectomy and resection of the epileptogenic cortex became seizure-free or had their seizure significantly reduced a mean follow-up period of 41.5 months. We conclude that CDs have intrinsic epileptogenicity, while DNTs have epileptogenicity not intrinsically but in encompassed cortical surface areas.

Adolescent↗
PubMed2000

Acute and subacute toxicities of theophylline are directly reflected by its plasma concentration in dogs.

The purpose of this study was to evaluate the relationship between acute and subacute toxicity and blood levels of theophylline in dogs. Theophylline was administered intravenously into dogs once (at doses of 50, 100 and 150 mg/kg) or for 4 weeks (at doses of 20, 35 and 70 mg/kg/day). In the single dose toxicity study, by increasing the dose of theophylline, plasma concentration increased and the severity of toxic symptoms were intensified. After a single dosing of theophylline, accentuated heart rate and vomiting were observed at a concentration of more than 67 micrograms/ml, and excitement, spasm and hyperpnea were observed at more than 130 micrograms/ml. Animals died after tonic convulsion at 180 micrograms/ml. In the repeated dose toxicity study, the plasma concentration of theophylline increased dependent on dosage, and was not affected by repeated dosing. Even under these conditions, the toxic symptoms were quite similar to those of the single dose, except for an additional decrease in movement, body weight reduction and myocardial lesion. These present results suggest that the severity of theophylline toxicity is dependent on its plasma concentrations rather than accumulated dosages. The blood concentration of theophylline-treated patients should be maintained within the therapeutic range in order to diminish risk.

Animals↗
PubMed1999

Negative regulatory role of the Escherichia coli hfq gene in cell division.

We found that the hfq::cat mutant strain produced minicells at high frequency. Minicell production by the mutant strain was more prominent in poor media and in the stationary phase than in rich media and in the exponentially growing phase. The amount of the cell division protein FtsZ increased up to two- to threefold of the wild-type cells in the hfq::cat mutant in the stationary phase, while such differences were not observed in the exponentially growing phase. Increased ftsZ mRNA levels were also observed in the hfq::cat mutant in the stationary phase. These results suggest a negative regulatory role of the DNA-, RNA-binding protein Hfq in cell division in the stationary phase.

Bacterial Proteins↗
PubMed1999

Overproduction of the outer-membrane proteins FepA and FhuE responsible for iron transport in Escherichia coli hfq::cat mutant.

We found that 82- and 76-kDa proteins in the outer-membrane fractions were overproduced in the hfq::cat mutant cells when grown in synthetic media. Expression of these proteins was repressed by addition of FeCl(3) in the mutant as well as in the wild type. It was revealed that these are FepA and FhuE proteins involved in iron transport. The hfq::cat mutant was more susceptible to killing by hydrogen peroxide, probably due to the excess incorporation of iron, which potentially generates hydroxyl radicals. Increased incorporation of iron in the hfq::cat mutant was also confirmed by the suppressive effect on the ftsH1 mutation. These results suggest that the hfq gene product is involved in the defense mechanism against oxidative stress.

Bacterial Outer Membrane Proteins↗
PubMed1999

Isolation of the murI gene from Brevibacterium lactofermentum ATCC 13869 encoding D-glutamate racemase.

The murI gene encoding D-glutamate racemase plays an important role in the biosynthesis of D-glutamic acid, an essential component of cell wall peptidoglycan of almost all eubacteria. A DNA fragment that could rescue the auxotrophy of D-glutamic acid in the Escherichia coli murI mutant strain WM335 was isolated from Brevibacterium lactofermentum ATCC 13869 belonging to the coryneform bacteria. DNA sequencing reveals that it encodes a protein of 284 amino acid residues, which shows a high level of homology with D-glutamate racemases from several other bacteria.

Amino Acid Isomerases↗
PubMed1999

Escherichia coli cafA gene encodes a novel RNase, designated as RNase G, involved in processing of the 5' end of 16S rRNA.

We found that the Escherichia coli cafA::cat mutant accumulated a precursor of 16S rRNA. This precursor migrated to the same position with 16.3S precursor found in the BUMMER strain that is known to be deficient in the 5' end processing of 16S rRNA. Accumulation of 16. 3S rRNA in the BUMMER mutant was complemented by introduction of a plasmid carrying the cafA gene. The mutant type cafA gene cloned from the BUMMER strain had a 11-bp deletion in its coding region. A small amount of the mature 16S rRNA was still formed in the cafA::cat mutant. This residual activity was found to be due to RNase E encoded by the rne/ams gene by rifampicin-chase experiments of the cafA::cat ams1 double mutant. These results indicated that the cafA gene encodes a novel RNase responsible for processing of the 5' end of 16S rRNA.

Bacterial Proteins↗
PubMed1999

A murC gene from coryneform bacteria.

The upstream flanking region of the ftsQ and ftsZ genes of Brevibacterium flavum MJ233, which belongs to the coryneform bacteria, was amplified by the inverse polymerase chain reaction method and cloned in Escherichia coli. Complementation analysis of E. coli mutant with a defective cell-wall synthesis mechanism with the cloned fragment and its DNA sequencing indicated the presence of the murC gene, encoding UDP-N-acetylmuramate:L-alanine ligase involved in peptidoglycan synthesis, just upstream from the ftsQ gene. The B. flavum murC gene could encode a protein of 486 amino acid residues with a calculated molecular mass of 51 198 Da. A 50-kDa protein was synthesized by the B. flavum murC gene in an in vitro transcription/translation system using E. coli S30 lysate. These results indicate that the genes responsible for cell-wall synthesis and cell division are located as a cluster in B. flavum similar to the E. coli mra region.

Amino Acid Sequence↗
PubMed1999

Stereotaxy for hypothalamic hamartoma with intractable gelastic seizures: technical case report

OBJECTIVE AND CLINICAL IMPORTANCE: We report a patient with a hypothalamic hamartoma treated by stereotactic radiofrequency thermocoagulation. CLINICAL PRESENTATION: A 15-year-old girl presented with a hypothalamic hamartoma associated with intractable gelastic and tonic seizures. There were no clinical signs of precocious puberty. Magnetic resonance imaging revealed an isointense suprasellar mass, about 1 cm in diameter. TECHNIQUE: A depth electrode was placed into the hamartoma using a computed tomography-compatible stereotactic frame. Depth electroencephalographic studies allowed us to record the seizure onset from the lesion, and stereotactic radiofrequency thermocoagulation produced seizure remission. CONCLUSION: These findings suggest that hypothalamic hamartoma itself has intrinsic epileptogenicity. We believe that this surgical treatment is effective for the relatively small hypothalamic hamartoma associated with intractable gelastic seizures.

Journal Article↗
PubMed1999

fcsA29 mutation is an allele of polA gene of Escherichia coli.

The cold-sensitive fcsA29 mutation of Escherichia coli was found to be a new type of cold-sensitive allele of the polA gene encoding DNA polymerase I, caused by an Asp(116)-->Asn change in the 5'-->3' exonuclease domain. The fcsA29 mutant showed typical polA mutant phenotypes such as UV sensitivity and unacceptability of recA mutation. Cold-sensitive growth of the mutant was suppressed by introduction of a sulA mutation, indicating that cell filamentation was due to the SOS response.

Alleles↗
PubMed1998

Ipidacrine (NIK-247), a novel antidementia, rapidly enters the brain and improves scopolamine-induced amnesia in rats during the Morris water maze task.

The effects of single and repeated administrations of ipidacrine (NIK-247, 9-amino-2, 3, 5, 6, 7, 8-hexahydro-1H-cyclopenta [b] quinoline monohydrochloride monohydrate) on scopolamine-induced spatial learning deficit were investigated in rats using the Morris water maze task. A single oral administration of ipidacrine (0.3 and 1 mg/kg) reduced the increased total latency induced by scopolamine in this task. The repeated administration of ipidacrine (1 mg/kg) of once a day for 5 successive days reduced the increased total latency induced by scopolamine to the levels of the saline-treated control rats in this task. In this pharmaco-kinetic study, ipidacrine was rapidly taken up into the brain within 5 min. Moreover, higher drug levels were observed mainly in the cortex and hippocampus, which both play important roles in learning and memory. Thus, a previous study together with this investigation indicate that ipidacrine improves amnesia which consists of the impairment of the working and reference memory in various animal models, suggesting that ipidacrine is a useful candidate for the therapy of patients with Alzheimer's disease.

Aminoquinolines↗
PubMed1997

DNA binding properties of the hfq gene product of Escherichia coli.

We found that plasmids isolated by alkaline-lysis method occasionally showed abnormal mobility on agarose gel electrophoresis. This abnormality was not detected after phenol extraction of plasmids, indicating that it was caused by proteinous factor(s). A 15-kDa protein was found in the plasmid preparations on SDS-PAGE. The sequence of eighteen N-terminal amino acid residues of the 15-kDa protein was identical with the host factor I (HF-I) encoded by the hfq gene at 95 min on the Escherichia coli chromosome map, which is known to be required for bacteriophage Qbeta replication. The HF-I protein was purified and in vitro DNA binding experiment was carried out. HF-I bound to both supercoiled DNA and linear DNA and the binding of HF-I seemed to be sequence-nonspecific.

Amino Acid Sequence↗
PubMed1997

Cloning, sequencing, and characterization of the ftsZ gene from coryneform bacteria.

Taking advantage of highly conserved domains present in the ftsZ genes from Escherichia coli, Rhizobium meliloti, and Bacillus subtilis, we designed degenerate oligonucleotides (oligos) corresponding to these regions. These oligos were used as primers in PCR in order to amplify DNA sequences from Brevibacterium flavum MJ233 chromosomal DNA. The PCR product was used as a probe to recover genomic fragments from a lambda library of Br. flavum MJ233. The complete nucleotide sequence (nt) of the cloned 4.2-kb EcoRI fragment containing the ftsZ homolog from Br. flavum MJ233 indicated that the deduced gene product of the Br. flavum ftsZ homolog is composed of 438 amino acids (aa) with a deduced molecular weight of 46.9 kDa. This size of molecular weight was also confirmed by the in vitro protein synthesis assay. Comparison of this aa sequence to the corresponding sequences from E. coli, Rh. meliloti, B. subtilis, and Streptomyces coelicolor revealed a high degree of conservation and suggested that the Br. flavum ftsZ homolog has a putative GTP binding motif and a GTP hydrolizing region. Expression of Br. flavum ftsZ gene in E. coli, JM109 inhibited its cell division, leading to filamentation. This suggested that the Br. flavum ftsZ product competed with the E. coli ftsZ product.

Amino Acid Sequence↗
PubMed1997

Functional relationship between Escherichia coli RNase E and the CafA protein.

We analyzed the functional relationship between the Escherichia coli RNase E and the CafA protein, which show extensive sequence similarity. The temperature-sensitive growth of the RNase E mutant strain ams1 was partially suppressed by multicopy plasmids bearing the cafA gene. Introduction of a cafA::cat mutation enhanced the temperature sensitivity of the ams1 mutant. These results suggest that there is a functional homology between these two proteins.

Bacterial Proteins↗
PubMed1997

Diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) controls the timing of cell division in Escherichia coli.

BACKGROUND: The timing of the cell division in Escherichia coli is highly regulated, but its mechanism has not been identified. Previously we have found that the cfcA1 mutation uncouples DNA replication and cell division and elevates the frequency of cell division. We further analysed the structure and the role of the cfc genes of cfcA11, a derivative of cfcA1, and another cfc mutant, cfcB1. RESULTS: The cfc mutants divided prior to the ordinary stage of cell division and produced many small cells with nucleoid. However, the cells grew exponentially, and the length of a cell cycle and the initiation mass for chromosome replication were not altered by the cfc mutations. These properties resulted from a reduction of the period between the nucleoid division and the cell division in a cell cycle, and a compensatory lengthening of the period between the cell division and the initiation of the next round of DNA replication. CfcA11 has a mutation in glySa which encodes the alpha-subunit of glycyl-tRNA synthetase, and cfcB1 has an IS2 insertion in apaH which encodes Ap4A hydrolase. The cfc properties of both cfc mutants were suppressed by a multicopy plasmid carrying apaH+, and the intracellular level of Ap4A in cfcA1 was 15-fold higher, and cfcB1 was 100-fold higher than their parent. Experiments using wild-type cells showed that a high level of Ap4A caused early cell division, and that a low level of Ap4A caused delayed cell division. CONCLUSION: Ap4A is a signal for the induction of cell division. High levels of Ap4A are responsible for the initiation of cell division. The glyS mutation permits an efficient synthesis of Ap4A.

Cell Cycle↗
PubMed1996

A cryptic plasmid pBL1 from Brevibacterium lactofermentum causes growth inhibition and filamentation in Escherichia coli.

A shuttle vector composed of pBL1, a 4.46-kb cryptic plasmid from coryneform bacterium Brevibacterium lactofermentum, and Escherichia coli vector pHSG298 was found to inhibit growth and cause cell filamentation in E coli. After construction of several deletions of pBL1, a 1.23-kb AccI-HindIII fragment was found responsible. DNA sequence analysis showed that this fragment contained a 726-bp-long open reading frame (ORF3), encoding a protein with 242 amino acid residues. Corresponding to ORF3, a 28-kDa protein was detected in an in vitro protein synthesis system. ORF3 was dispensable for the stable maintenance of pBL1 in coryneform bacteria.

Brevibacterium↗
PubMed1995

A murC gene in Porphyromonas gingivalis 381.

The gene encoding a 51 kDa polypeptide of Porphyromonas gingivalis 381 was isolated by immunoblotting using an antiserum raised against P. gingivalis alkaline phosphatase. DNA sequence analysis of a 2.5 kb DNA fragment containing a gene encoding the 51 kDa protein revealed one complete and two incomplete ORFs. Database searches using the FASTA program revealed significant homology between the P. gingivalis 51 kDa protein and the MurC protein of Escherichia coli, which functions in peptidoglycan synthesis. The cloned 51 kDa protein encoded a functional product that complemented an E. coli murC mutant. Moreover, the ORF just upstream of murC coded for a protein that was 31% homologous with the E. coli MurG protein. The ORF just downstream of murC coded for a protein that was 17% homologous with the Streptococcus pneumoniae penicillin-binding protein 2B (PBP2B), which functions in peptidoglycan synthesis and is responsible for antibiotic resistance. These results suggest that P. gingivalis contains a homologue of the E. coli peptidoglycan synthesis gene murC and indicate the possibility of a cluster of genes responsible for cell division and cell growth, as in the E. coli mra region.

Alkaline Phosphatase↗
PubMed1995

The pcsA gene is identical to dinD in Escherichia coli.

The pcsA68 mutant of Escherichia coli is a cold-sensitive mutant which forms long filaments with a large nucleoid in the central region at 20 degrees C. We here show that (i) the coding region for the pcsA gene is identical with orfY located upstream of pyrE and can be deleted without loss of viability; (ii) pcsA is also identical to dinD, a DNA damage-inducible gene, whose expression is regulated by the LexA-RecA system; (iii) the cold-sensitive phenotype of the pcsA68 mutation is suppressed by delta recA or lexA1 (Ind-) mutation, but not by sulA inactivation; (iv) overproduction of PcsA68 leads to inhibition of cell growth in recA+ and delta recA strains at 20 and 37 degrees C, but PcsA+ does not show such an effect at any temperature; (v) SOS response is induced in the pcsA68 mutant cells at 20 degrees C. We discuss the possible function of the pcsA gene, comparing it with the sulA or the dif-xerCD function. We also describe a new method for gene disruption with positive and negative selection.

Bacterial Proteins↗