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M Maekawa

Publications and source records attributed to M Maekawa.

At least 109 records · Page 6Linked to original sources
PubMed1997

Genetic mutations of butyrylcholine esterase identified from phenotypic abnormalities in Japan.

We have identified 12 kinds of genetic mutations of butyrylcholine esterase (BCHE) from phenotypic abnormalities, showing that BCHE activities were deficient or diminished in sera. These genetic mutations, detected by PCR-single-strand conformation polymorphism analysis and direct sequencing, consisted of one deletion (BCHE*FS4), nine missense (BCHE*24 M, *1005, *250P, *267R, *330I, *365R, *418S, *515C, *539T), and two nonsense mutations (BCHE*119STOP, *465STOP). All of the individuals deficient in serum BCHE activity were homozygous for silent genes (6 of 6). Fifty-eight percent of the individuals (31 of 53) with slightly reduced serum BCHE activity were heterozygous for silent genes. They also showed a higher frequency (47% as allele frequency) of the K-variant than the general population (17.5%). Finally, we confirmed low serum BCHE activity in 10 of 23 individuals heterozygous for silent genes.

Butyrylcholinesterase↗
PubMed1997

[Transient hyperphosphatasemia observed in a boy with acute lymphoblastic leukemia].

A detailed time course of alkaline phosphatase (ALP; EC3.1.3.1) activity of transient hyperphosphatasemia (TH) in a 9-year-old boy with acute lymphoblastic leukemia (ALL) is described. The patient's serum ALP activity rose transiently to 49 times the upper limit of normal adult, without any evidences of hepatic and bone disease. The half-life of ALP activity was calculated about 10 days. We characterized ALP isoenzymes by usual electrophoresis using cellulose acetate membrane (Titan III iso-vis) and polyacrylamide disc gel (AlkPhor), and isoelectric focusing using polyacrylamide slab gel. The former two methods showed typical two bands (fast-alpha 2 and alpha 2 beta bands) and the latter one method revealed more basic bands of liver and bone, suggesting the extensive sialylation. The patient complained fever and diarrhea. Enterococcus faecium was detected from his stool. Etiologically, two more patients in the same ward showed TH in the same period. It suggested TH would be occurred by infectious states. Awareness of such benign forms of hyperphosphatasemia not related to malignancy will aid the physician in the differential diagnosis of elevated ALP activity.

Alkaline Phosphatase↗
PubMed1996

Difference in selectivity to song note properties between the vocal nuclei of the zebra finch.

Responses to a single note from a zebra finch song and an artificially modified note were recorded from neurons in the vocal nuclei in the zebra finch. Response patterns recorded in the higher vocal center (HVC) and the lateral magnocellular nucleus of the neostriatum (IMAN) were compared. A subset of neurons were found to preferentially respond to the original temporal sequence of the components of the note and/or the specific harmonic structure of the note. These neurons were more common in the IMAN than in the HVC. These results suggest that response selectivity to both the harmonic and temporal pattern of the note increases as auditory information flows from the HVC to the IMAN.

Acoustic Stimulation↗
PubMed1996

Relative ratios of mRNA molecules encoded by genes with homologous sequences using fluorescence-based single-strand conformation polymorphism analysis.

The combination of reverse transcribed (RT)-PCR and fluorescence-based single-strand conformation polymorphism (SSCP) analysis is proposed for the quantitative determination of the ratio of mRNA molecules with homologous sequences. We applied this procedure to lactate dehydrogenase (LDH) subunits A and B. We designed fluorescence labeled common PCR primers in the sequences highly homologous between LDH-A and LDH-B cDNAs and performed RT-PCR-SSCP analysis. When PCR efficiency was almost the same between the different target sequences, analysis of mixtures of known amounts of LDH-A and LDH-B revealed linear and precise proportions of LDH-A mRNA. Template concentrations and PCR cycles did not affect the determination of proportions of LDH-A to total LDH. The present procedure could be easily applied to investigation of expression levels of genes encoding mRNAs with homologous sequences.

Amino Acid Sequence↗
PubMed1996

The small GTP-binding protein Rho binds to and activates a 160 kDa Ser/Thr protein kinase homologous to myotonic dystrophy kinase.

The small GTP-binding protein Rho functions as a molecular switch in the formation of focal adhesions and stress fibers, cytokinesis and transcriptional activation. The biochemical mechanism underlying these actions remains unknown. Using a ligand overlay assay, we purified a 160 kDa platelet protein that bound specifically to GTP-bound Rho. This protein, p160, underwent autophosphorylation at its serine and threonine residues and showed the kinase activity to exogenous substrates. Both activities were enhanced by the addition of GTP-bound Rho. A cDNA encoding p160 coded for a 1354 amino acid protein. This protein has a Ser/Thr kinase domain in its N-terminus, followed by a coiled-coil structure approximately 600 amino acids long, and a cysteine-rich zinc finger-like motif and a pleckstrin homology region in the C-terminus. The N-terminus region including a kinase domain and a part of coiled-coil structure showed strong homology to myotonic dystrophy kinase over 500 residues. When co-expressed with RhoA in COS cells, p160 was co-precipitated with the expressed Rho and its kinase activity was activated, indicating that p160 can associate physically and functionally with Rho both in vitro and in vivo.

Amino Acid Sequence↗
PubMed1996

Sensitive detection of loss of heterozygosity in the TP53 gene in pancreatic adenocarcinoma by fluorescence-based single-strand conformation polymorphism analysis using blunt-end DNA fragments.

We have developed a fluorescence-based single-strand conformation polymorphism analysis to detect Haelil-sensitive polymorphic sites in intron 1 of the TP53 gene. It is important to treat the PCR products with Klenow fragment to remove a 3'-protruding nucleotide from the amplified DNA fragments added during the reaction in order to obtain a single peak for each allele. A comparison of the signal profiles of two alleles with those of normal heterozygotes by data processing using computer software has enabled sensitive detection of loss of heterozygosity (LOH) from clinical materials with a fraction of tumor cells below 10%. In analysis of 14 pancreatic carcinomas in which the proportion of the tumor cells is usually low due to the abundance of the stromal component, 7 samples (50%) were informative and 5 of the 7 (71.4 %) were positive for LOH at the TP53 locus. This approach would be useful for allelotyping tumors with low cellularity, as well as other clinical samples such as biopsied specimens and paraffin embedded tissues.

Adenocarcinoma↗
PubMed1996

Somatosensory evoked potentials following proprioceptive stimulation of finger in man.

Brisk passive flexion of the proximal interphalangeal joint of the middle finger, produced by using a newly devised instrument, elicited evoked potentials on the scalp. The present study carefully excluded the possible contribution of sensory modalities other than proprioception. The initial part of cortical response was a positive deflexion at the contralateral central area (P1 at 34.6 ms after the stimulus). This was followed by a midfrontal negative wave (N1 at 44.8 ms) and a clear positivity at the contralateral centroparietal area (P2 at 48.0 ms). The evoked responses persisted in spite of the abolition of cutaneous and joint afferents of the finger caused by ischemic anesthesia, but they were lost by ischemic anesthesia of the forearm. Thus, the cortical evoked responses obtained in this study most probably reflect muscle afferent inputs. The scalp distribution of P1 suggested that its cortical generator source was different from that of the N20-P20 components of evoked potentials to electrical median nerve stimulation. Brodmann areas 2 and 3a of human brain, which are known to receive deep receptor inputs, are the most plausible generator sites for the early components of the proprioception-related evoked responses. The amplitude of P2 was related to the velocity but not to the magnitude of movement. In conclusion, the present study established a method for recording the evoked responses to the brisk passive movement of the finger joint, which mainly reflect the dynamic aspects of proprioception mediated through muscle afferent.

Adult↗
PubMed1996

Three different point mutations in the butyrylcholinesterase gene of three Japanese subjects with a silent phenotype: possible Japanese type alleles.

OBJECTIVE: To investigate genetic mutations in three Japanese subjects homozygous for silent butyrylcholinesterase mutations. METHODS AND RESULTS: One of them was compound heterozygous for two mutations; GGA(Gly) to CGA(Arg) at codon 365 (G365R) and CAA(Gln) to TAA(Ter) at codon 119 (Q119X). The other two subjects were homozygous for different missense mutations: CGT(Arg) to TGT(Cys) at codon 515 (R515C) and G365R, respectively. Simple identification methods for all of the mutations were developed and applied for family analysis and to control individuals. Two mutations, G365R and R515C, have been reported in the Japanese population, while the nonsense mutation Q119X was discovered in the present study. Genetic heterogeneity between human populations with regard to the butyrylcholinesterase gene was suggested. CONCLUSIONS: Among the three mutations found in this investigation, one was novel, and none of these mutations have been reported outside Japan.

Adult↗
PubMed1996

Augmented very low frequency component of heart rate variability during obstructive sleep apnea.

After documenting the presence of obstructive sleep apnea syndrome (OSAS) through polysomnographic monitoring, we performed simultaneous ambulatory recordings of electrocardiogram, oronasal airflow, and pulse oximetry on 12 OSAS patients with normal autonomic nervous function for a period of 24 hours. The power spectrum of heart rate variability was investigated before and during treatments using dental appliances. Freuquency domain analysis showed that the very low frequency component of heart rate (0.008-0.04 Hz) was increased in OSAS patients and that a very low frequency peak appeared during episodes of obstructive sleep apnea. The increase in very low frequency identification was synchronized with episodes of absence of air exchange or hypoxemia (decreased arterial oxygen saturation) that occurred repeatedly at a cycle length of 25-120 seconds in our subjects. Frequency domain analysis of heart rate variability before and during prosthetic mandibular advancement treatment showed that only the very low frequency was significantly decreased during prosthetic mandibular advancement treatment, whereas the other frequencies, i.e. high, low, and ultralow frequency component values, showed no significant changes. Time domain analysis of heart rate variability before and during prosthetic mandibular advancement treatment showed no significant changes in any of these parameters. Frequency domain analysis of heart rate variability during nocturnal sleep, especially investigation of very low frequency and very low frequency peak, can be a noninvasive low-cost approach to diagnose and even better monitor subjects undergoing treatment at home, particularly considering that R-R intervals can be extracted from pulse oximetry and that analysis software programs are already commercially available.

Adult↗
PubMed1996

Peritubular myoid cells in the testis: their structure and function.

Peritubular myoid cells, surrounding the seminiferous tubules in the testis, have been found in all mammalian species, but their organization in the peritubular interstitial tissue varies by species. In laboratory rodents, including rats, hamsters and mice, only one layer of myoid cells is seen in the testis. The cells in these animals are joined by junctional complexes as are epithelial cells. On the other hand, several cellular layers exist in the lamina propria of the seminiferous tubule in the human and some other animals. Myoid cells contain abundant actin filaments which are distributed in the cells in a species-specific manner. In the rat, the filaments within one myoid cell run both longitudinally and circularly to the long axis of the seminiferous tubule, exhibiting a lattice-work pattern. The arrangement of the actin filaments in the cells changes during postnatal development, and the disruption of spermatogenesis, such as cryptorchidism, seems to affect further the arrangement of the filaments. Other cytoskeletal proteins, including myosin, desmin/vimentin and alpha-actinin, are also found in the cells. Myoid cells have been shown to be contractile, involved in the transport of spermatozoa and testicular fluid in the tubule. Several substances (prostaglandins, oxytocin, TGF beta, NO/cGMP) have been suggested to affect the contraction of the cell, though the mechanisms of the contraction are still unknown. Recent in vitro studies have demonstrated that the cells secrete a number of substances including extracellular matrix components (fibronectin, type I and IV collagens, proteoglycans) and growth factors (PModS, TGF beta, IGF-I, activin-A). Some of these substances are known to affect the Sertoli cell function. Furthermore, it has been reported that myoid cells contain androgen receptors and are involved in retinol processing. Considering all this, it is evident that peritubular myoid cells not only provide structural integrity to the tubule but also take part in the regulation of spermatogenesis and the testicular function. Their precise roles, however, remain to be solved.

Actins↗
PubMed1996

Myofibroblasts in the lamina propria of human semi-niferous tubules are dynamic structures of heterogeneous phenotype.

Myofibroblasts of the lamina propria of human seminiferous tubules were studied in testes having normal or slightly reduced spermatogenesis by means of electron microscopy, confocal laser microscopy and immunocytochemistry. Myofibroblasts are large, flat individual cells braced in a network of microfibrils and collagen fibrils in the tubular wall. They are arranged in discontinuous cell layers with interposed layers of an extracellular matrix. Myofibroblasts of the lamina propria exhibit an unique cell shape with the peripheral cytoplasm split up in two or more layers. After FITC-phalloidin staining and by means of confocal laser microscopy, actin filaments of variable orientation are visible in their cytoplasm. The thickness and preferential direction of actin filaments differ in the outer and innermost cell layers. The myofibroblasts express both antigens of smooth muscle cells (alpha-smooth muscle actin, pan-actin, desmin, GB 42, smooth muscle myosin), and of connective tissue cells (vimentin, fibroblast surface protein). The variable expression of these antigens evidenced the existence of different phenotypes of myofibroblasts. Immunoreactivity for basic fibroblast growth factor and transforming growth factor beta as well as for components of the extracellular matrix indicate that these agents may be important for the phenotypic differentiation of the lamina propria cells. The detection of CNPase-and galactocerebroside-immunoreactivity in a number of lamina propria cells and some cells of the intertubular tissue gives rise to the hypothesis that components of the testicular tissue share some structural similarities with glia cells of the nervous system. Finally, immunoreactivities for the neuronal and endothelial nitric oxide synthase, soluble guanylyl cyclase, cyclic GMP, calmodulin, calcium-dependent protein kinase II and glutamate indicate that the contractility of myofibroblasts in the lamina propria of human seminiferous tubules may be in part modulated by the NO/cGMP-system.

Aged↗
PubMed1996

Spontaneous regression of intracranial arteriovenous malformation on PET.

We report a case of spontaneous regression of intracranial arteriovenous malformation (AVM) detected by PET in a 57-yr-old woman who had suffered repeated ruptures of the AVM at 28, 30 and 31 yr of age associated with pregnancy. The rupture at this hospitalization was the most critical, and after repeated ruptures for 1 mo, the AVM regressed spontaneously. The decreased cerebral blood volume (CBV) in the AVM indicated regression. The flow-to-volume (CBF/ CBV) ratios surrounding the AVM increased. The metabolic rate for oxygen (CMRO2) did not correlate with her improved neurological status, and an imbalance between CBF and CMRO2 was recognized.

Cerebrovascular Circulation↗
PubMed1996

[Clinical significance of serum cholinesterase concentrations determined by enzyme-linked immunosorbent assay (ELISA)].

We developed a sensitive enzyme-linked immunosorbent assay (ELISA) for measurement of the protein mass of serum cholinesterase (CHE). In our ELISA system, a combination of a monoclonal antibody (a capture antibody) and an anti-CHE rabbit antibody (a second antibody) against CHE were used for the specific determination of CHE. The formed antigen-antibody complexes were detected with an alkaline phosphatase-labeled anti-rabbit IgG antibody. Using this ELISA system, we investigated for a possible relationship between the protein mass value and the catalytic activity of serum CHE in three patients groups with different clinical findings: control subjects selected randomly from outpatients (Group A), individuals with a low serum CHE activity including genetic variants (Group B) and patients with sarin poisoning (Group C). The CHE mass value correlated closely with the CHE activity in Group A, as previously reported. In Group B, a less significant correlation than in Group A was observed because both the CHE mass value and the CHE activity were disturbed at relatively lower levels. However, no discrepant cases were observed. On the other hand, in Group C, patients with serious sarin poisoning showed significant discrepancies between the mass value and activity of CHE before medical treatments, indicating that the inhalation of sarin did not affect the protein mass level but did affect the activity of serum CHE. As the patients recovered during the treatments, their CHE activities increased to the levels expected from the regression curve obtained with Group A, whereas the mass values were almost unchanged. In conclusion, protein mass determination of serum CHE provides valuable information concerning the target value of the serum CHE activity for the treatment of patients with organophosphate insecticide poisoning as well as for investigating the specific activity of genetic variants of serum CHE.

Animals↗
PubMed1995

Genetic basis of the silent phenotype of serum butyrylcholinesterase in three compound heterozygotes.

Three Japanese patients showed very low butyrylcholinesterase activity in their sera and appeared to be homozygous for silent genes for butyrylcholinesterase. From DNA analysis, all three patients were compound heterozygotes: GGA(Gly) to CGA(Arg) at codon 365 (G365R) and TTC(Phe) to TCC(Ser) at codon 418 (F418S) in patient 1, G365R and CGT(Arg) to TGT(Cys) at codon 515 (R515C) in patient 2 and ACT(Thr) to CCT(Pro) at codon 250 (T250P) and AGA(Arg) to TGA(Stop) at codon 465 (R465X) in patient 3. The K-variant, GCA(Ala) to ACA(Thr) at codon 539, was also found in patients 1 and 2. Simple identification methods for all the mutations were developed and applied to family analysis and control individuals. The mutant alleles (with silent gene and K-variant) were segregated as predicted by theory in pedigrees of patients 1 and 2. Four of the mutations, F418S, R515C, T250P and R465X, were initially discovered in Japan and genetic heterogeneity among the human population for the butyrylcholinesterase gene was suggested.

Alleles↗
PubMed1995

Changes in the arrangement of actin filaments in myoid cells and Sertoli cells of rat testes during postnatal development and after experimental cryptorchidism.

BACKGROUND: Abundant actin filaments are present in myoid cells and Sertoli cells in the testis. In the adult rat, the filaments form a lattice arrangement within the myoid cell, and show a hexagonal pattern in the basal junctional regions of Sertoli cells. METHODS: Isolated seminiferous tubules and frozen sections were prepared from juvenile to adult Wistar rat testes, stained with FITC-conjugated phalloidin, and observed by confocal microscopy. Unilateral cryptorchidism was induced in adult rats, and seven days later, their testes were also examined. RESULTS: In the myoid cell, parallel actin filaments running circularly around the seminiferous tubules were observed at 15 and 20 days of age. Then, at 30 days, actin filaments arranged longitudinally along the tubular long axis appeared in addition to the circular bundles. A lattice arrangement of actin-filament bundles in myoid cells became obvious at 40 days, when elongated spermatids are found in the tubule. Actin filaments in the basal junctional regions of Sertoli cells did not acquire the hexagonal pattern seen in the adult testis until 30 days of age. In the cryptorchid testes, the arrangement of actin filaments in the both cells showed a remarkable change compared to the control testis; the filaments became thinner and disrupted. CONCLUSIONS: A lattice arrangement of the actin filaments in the myoid cell appear at around 30 days, before the completion of spermatogenesis. A hexagonal pattern of the filaments in the junctional regions of Sertoli cells has already developed at this age. Cryptorchidism affects the actin filaments of the both cells.

Actins↗
PubMed1995

Lactate dehydrogenase M-subunit deficiencies: clinical features, metabolic background, and genetic heterogeneities.

Lactate dehydrogenase M-subunit deficiency was first reported 1980 as an exertional myoglobinuria. Since then, 6 Japanese and 3 Caucasian families have been reported. Also, typical skin lesions were observed in 1 Japanese patient. Since then, 2 families, one Japanese and one Caucasian, have been found with this typical skin eruption. The metabolic background of exertional myoglobinuria was demonstrated as a result of the impaired reoxidation of NADH produced by glyceraldehyde-3-phosphate-dehydrogenase (G3PD) action. The excess NADH was partly reoxidized by the action of alpha-glycerophosphate dehydrogenase abundant in cytosolic fraction of skeletal muscle. This enzyme reoxidizes excess NADH simultaneously draining out triose phosphate from the glycolytic pathway. Abortive glycolysis results in impaired ATP production followed by rhabdomyolysis. Genomic analysis revealed the heterogeneities of the mutations of this disease.

Adolescent↗
PubMed1995

Mutagenicity of O-diazoacetyl-L-serine (azaserine) and 6-diazo-5-oxo-L- norleucine (DON) in a soybean test system.

The mutagenicity of O-diazoacetyl-L-serine (azaserine) and 6-diazo-5-oxo-L-norleucine (DON), glutamine analogues, were assayed in heterozygous soybean plants (Y11y11), according to the appearance of mutational spots (yellow, dark green and twin) on the leaves. The mutagenicity of azaserine was detected at 0.1 mg/ml, and that of DON, at 0.05 mg/ml. DON was strongly cytotoxic at doses exceeding 0.1 mg/ml. After azaserine and DON treatment, large spots which occupied more than half the leaflet were found in the first and second compound leaves. The glutamine analogues increased the frequency of yellow spots much more than dark green spots or twin spots. Light green spots were observed on y11y11 plants. Azaserine and DON induce somatic crossing over, point mutation and segmental loss as major effects.

Azaserine↗