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Biomedical subjects

K Murayama

Publications and source records attributed to K Murayama.

At least 73 records · Page 4Linked to original sources
PubMed1999

An electrophysiological follow-up study on acquired unilateral nyctalopia.

PURPOSE: To describe the clinical picture and electrophysiological findings in acquired unilateral nyctalopia. METHODS: A patient who had acquired unilateral visual loss with normal fundus was followed for a period of 2.5 years with basic ophthalmological examinations including standard electroretinogram and photopic on and off responses. RESULTS: A 46-year-old woman suffered from acquired unilateral nyctalopia. She complained of photopsia and blurred vision in her left eye. The initial examination of the left eye showed 1+ cells in the anterior chamber and a granular appearance in the fovea. After 1 month of treatment she still complained of photopsia in her left eye. Ophthalmoscopy and fluorescein angiography revealed no abnormality in either eye. A bright flash electroretinogram (ERG) in the left eye was a negative shape. Photopic ERG elicited by a 150 ms stimulus showed a depressed b-wave and enhanced a- and d-waves in the left eye. CONCLUSIONS: This ERG waveform suggested that the transmission between photoreceptor and on-bipolar cell might be affected by idiopathic retinal disease.

Electroretinography↗
PubMed1999

Crystallization and preliminary X-ray diffraction studies of Streptococcus pyogenes plasmid pSM19035-encoded omega transcriptional repressor.

The transcriptional repressor, omega protein, from the Streptococcus pyogenes broad-host-range plasmid pSM19035 was crystallized at pH 7. 5 and 8.5 by the vapour-diffusion method using PEG 4000 as precipitant. Two crystal forms were obtained; the first belongs to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2 and the second to the hexagonal space group P6(1) or P6(5). The crystals are most likely to contain one omega protein in the asymmetric unit, with V(m) values of 3.2 and 3.5 A(3) Da(-1), respectively. The crystals diffract X-rays to 2.4 and 2.9 A resolution for the tetragonal and hexagonal systems, -respectively.

Bacterial Proteins↗
PubMed1999

Proteolipid protein gene duplications causing Pelizaeus-Merzbacher disease: molecular mechanism and phenotypic manifestations.

Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder characterized by dysmyelination of the central nervous system (CNS) caused by mutations involving the proteolipid protein gene (PLP). In addition to point and frameshift mutations in the coding region, duplications involving the entire PLP have been recognized recently as a major genetic abnormality causing PMD. We devised an interphase fluorescence in situ hybridization (FISH) assay to establish an efficient screening test for PLP duplication. Thirteen patients from 11 Japanese PMD families were determined to have PLP duplications. This molecular diagnostic FISH test also readily detected female carriers. Molecular analysis revealed that the size of the duplication and location of the breakpoints showed striking variation. Fiber FISH demonstrated that the duplication is tandem in nature. Haplotype analysis indicated an intrachromosomal origin for the duplication. These results suggest that an unequal sister chromatid exchange in male meiosis is likely to be the major mechanism leading to the formation of the duplication. Patients with the duplication commonly present with a mild PMD phenotype. Two patients with an exceptionally severe clinical phenotype carried large duplications, suggesting that either the larger duplicated segment incorporates additional dosage-sensitive genes or that the location of the duplication junction may affect the phenotype.

Adolescent↗
PubMed1999

[Marked thrombocytopenia after high-dose intravenous gamma globulin in a pregnant woman with idiopathic thrombocytopenic purpura].

A 35-year-old pregnant woman had thrombocytopenia with a platelet count of 6.3 x 10(4)/microliter. After her third normal delivery, peripheral blood studies revealed that the patient had a normal Hb concentration and leukocyte count, with mild thrombocytopenia. A diagnosis of idiopathic thrombocytopenic purpura (ITP) was made based on the high megakaryocyte count of 338/microliter and PAIgG of 40.8 ng/10(7) cells in January 1995. The patient was followed without treatment. She was 9 weeks pregnant on June 7, 1996, and desired an abortion. Her platelet count was 6.3 x 10(4)/microliter, leukocyte count 8,600/microliter, and Hb 13.7 g/dl at the time. She was given high-dose intravenous gammaglobulin (Globenin-I) at 400 mg/kg/day for 5 consecutive days. The platelet count was found to have decreased markedly, to 0.9 x 10(4)/microliter on June 11. The percentage reduction in the Hb concentration, leukocyte count, and platelet count after gammaglobulin treatment was 11.7%, 46.6%, and 85.8%, respectively. The PAIgG titer had increased to 181.2 ng/10(7) cells on June 17, but hypergammaglobulinemia was suspected. The patient was started on prednisolone on June 24, and an abortion was performed on July 29. The mechanism of thrombocytopenia after infusion of Globenin-I was unknown. We suspect that Globenin-I treated with polyethylene glycol was one of the possible causes of myelosuppression in this case.

Adult↗
PubMed1999

[Prevalence rate of allergy to Japanese cedar pollen in Tokyo--from field investigation in 1996 by Tokyo Japanese Cedar Pollen Allergy Measurements and Review Committee].

Prevalence rate of allergy to Japanese cedar pollen was investigated by means of questionnaires and immunological examinations in residents of 3 regions in Tokyo (Akiruno city, Chofu city, and Ota ward). The results were as follows: 1) the prevalence rate of allergy to Japanese cedar pollen in Tokyo was 25.7% in Akiruno city, 21.1% in Chofu city, and 17.7% in Ota ward in 1996; 2) stratification by the age reveal that the prevalence rate was the highest in the age group of 30 to 44, and the group showed prevalence rate of above 40% in Akiruno city; 3) overall prevalence rate of Tokyo was 19.4% in 1996, which was approximately twice as much as that in 1985; 4) increase in prevalence rate in the recent decade was most significant in Akiruno city where the largest number of Japanese cedar pollen was detected in the air, and prevalence rate tended to rise in the young group of 14 or less.

Adolescent↗
PubMed1999

[Clinical studies of faropenem in the field of obstetrics and gynecology].

The clinical effect of faropenem was evaluated in 165 ambulatory patients with various infections in the field of obstetrics and gynecology at 10 institutions in Yamagata Prefecture. The results obtained are summarized below. 1. The rate of efficacy, as determined from the clinical effect following 3- to 7-day repeated administration at a dose of 600 mg/day, was 97.9% (46/47) for intrauterine infections, 92.0% (23/25) for adnexitis, 93.8% (15/16) for external genital infections, 88.9% (8/9) for mastitis, 94.0% (63/67) for cystitis, and 100% (1/1) for cervicitis. The overall efficacy rate was estimated to be 94.5% (156/165). 2. The rate of clinical efficacy, as classified by isolate, was high, 95.1% for Gram-positive bacteria, 100% for Gram-negative bacteria, and 100% for anaerobes. As for bacteriological response classified by isolate, the eradication rate was high, 91.4% (74/81) for Gram-positive bacteria, 98.4% (62/63) for Gram-negative bacteria, 89.5% (17/19) for anaerobes, and 93.9% (153/163) in all. 3. No adverse reactions or laboratory abnormalities were observed in any patient. The results presented suggest that faropenem is a highly safe and effective antibiotic for the treatment of obstetric or gynecological infections of various kinds in an ambulatory setting.

Adult↗
PubMed1998

Identification of multidrug resistant protein 1 of mouse leukemia P388 cells on a PVDF membrane using 6-aminoquinolyl-carbamyl (AQC)-amino acid analysis and World Wide Web (WWW)-accessible tools.

Multidrug resistant protein 1 (MDR1) in a doxorubicin-resistant mouse leukemia cell line (P388/DOX) was identified using its amino acid composition combined with protein database searching (ExPASy and EMBL PROPSEARCH) via the World Wide Web. The proteins were separated by one-dimensional SDS-polyacrylamide gel electrophoresis, blotted onto a polyvinylidene fluoride membrane, and stained with Coomassie brilliant blue. A 160-kDa protein band was acid-hydrolyzed in the vapor phase (6 N HC1) and converted to 6-aminoquinolyl-carbamyl (AQC)-amino acids without extraction of the amino acids from the membrane. The amino acid composition of the protein was determined using the sensitive AQC-amino acid analysis method, improving our previously described method. The improved method involved using a Cosmosil 5C8-MS column instead of a Pegasil C8; replacement of the mobile phase A, constituent, 75 mM ammonium phosphate (pH 7.5), with 30 mM sodium phosphate buffer (pH 7.2); and slight modification of the separation program (9). All manipulations for protein hydrolysis and AQC derivatization were carried out in a hood using clean tools. This minimized contamination of amino acids at the low femtomolar level. A database search was carried out with bovine serum albumin as a calibration protein. MDR1 in P388/DOX was ranked first by both databases with high reliability (score 14 for ExPASy, distance 1.34 for EMBL).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Beta-casomorphin-5 stimulates neurite outgrowth in a mouse neuroblastoma cell line (Neuro-2a).

We studied the effect of beta-casomorphin-5 (mu-acting opioid peptides derived from milk protein beta-casein) on neurite outgrowth of mouse neuroblastoma cell line, Neuro-2a. Beta-casomorphin-5 stimulated neurite outgrowth of Neuro-2a cells in a naloxone-reversible manner. The stimulating effect of beta-casomorphin-5 was observed even at picomolar concentrations. The selective mu-agonist, (D-Ala2, N-Me-Phe4, Gly5-ol)-enkephalin (DAMGO) exhibited the similar stimulating effect only at micromolar concentrations. On the other hand, (D-Pen(2,5))-enkephalin (DPDPE) (a delta-agonist), U-50,488 (a kappa-agonist), and endogenous opioid peptides, such as enkephalins and dynorphin A (1-13), showed no such stimulating effect. These results suggest that the neurite outgrowth-stimulating action of beta-casomorphin-5 may be mediated via a receptor which has mu-like characteristics and high sensitivity to beta-casomorphin-5, and that beta-casomorphins may play a role as a neurite elongation factor during the suckling period.

Animals↗
PubMed1998

Tissue-specific involvement of multiple mitochondrial DNA deletions in familial mitochondrial myopathy.

It is still uncertain how deleted mitochondrial DNA (mtDNA) is distributed to each tissue during development, although deletions of mtDNA have been extensively observed in various pathologic conditions. This paper presents two Japanese siblings with progressive external ophthalmoplegia exhibiting multiple mtDNA deletions. In one patient, similar multiple mtDNA deletions were found in skeletal muscle specimens as well as in the spinal cord but not in the myocardium, liver or leukocytes. A similar deletion pattern was found in the skeletal muscle but not in the leukocytes of the other patient. The results suggest the complex mechanism to generate, expand and eliminate the deleted mtDNA in humans.

Adult↗
PubMed1998

Inactivation of human manganese-superoxide dismutase by peroxynitrite is caused by exclusive nitration of tyrosine 34 to 3-nitrotyrosine.

Peroxynitrite has recently been implicated in the inactivation of many enzymes. However, little has been reported on the structural basis of the inactivation reaction. This study proposes that nitration of a specific tyrosine residue is responsible for inactivation of recombinant human mitochondrial manganese-superoxide dismutase (Mn-SOD) by peroxynitrite. Mass spectroscopic analysis of the peroxynitrite-inactivated Mn-SOD showed an increased molecular mass because of a single nitro group substituted onto a tyrosine residue. Single peptides that had different elution positions between samples from the native and peroxynitrite-inactivated Mn-SOD on reverse-phase high performance liquid chromatography were isolated after successive digestion of the samples by staphylococcal serine protease and lysylendopeptidase and subjected to amino acid sequence and molecular mass analyses. We found that tyrosine 34 of the enzyme was exclusively nitrated to 3-nitrotyrosine by peroxynitrite. This residue is located near manganese and in a substrate O-2 gateway in Mn-SOD.

Amino Acid Sequence↗
PubMed1998

Acrosin accelerates the dispersal of sperm acrosomal proteins during acrosome reaction.

Using homologous recombination, we have previously produced male mice carrying a disruptive mutation (Acr-/-) in the acrosin gene. Although Acr-/- mouse sperm lacking the acrosin protease activity still penetrated the zona pellucida and fertilized the egg, the mutant sperm exhibited a delay in penetration of the zona pellucida solely at the early stages after insemination. To further elucidate the role of acrosin in fertilization, we have examined the involvement of acrosin in the acrosome reaction of sperm using the Acr-/- mutant mice. When the ability of sperm to adhere (attach) and bind to the zona pellucida of cumulus-free eggs was assessed in vitro, no significant difference was observed among Acr+/+, Acr+/-, and Acr-/- mouse sperm. Immunocytochemical analysis demonstrated that the release of several acrosomal proteins from the acrosome of Acr-/- mouse sperm was significantly delayed during the calcium ionophore- and solubilized zona pellucida-induced acrosome reaction, despite normal membrane vesiculation. These data indicate that the delayed sperm penetration of the zona pellucida in the Acr-/- mouse results from the altered rate of protein dispersal from the acrosome and provide the first evidence that the major role of acrosin is to accelerate the dispersal of acrosomal components during acrosome reaction.

Acrosin↗
PubMed1998

Inactivation and destruction of conserved Trp159 of Fe-superoxide dismutase from Porphyromonas gingivalis by hydrogen peroxide.

The superoxide dismutase (SOD) of Porphyromonas gingivalis, an obligate anaerobe, was purified from Escherichia coli (sodA sodB mutant) harboring the P. gingivalis SOD-encoding gene. The purified protein contained both iron and a small amount of manganese. Iron- and manganese-reconstituted SOD, which contained one of these metals exclusively, showed specific activities of 1000 and 1200 U/mg/mol of metals/subunit, respectively. These values were similar to the specific activity of the native enzyme purified from the recombinant E. coli strain. The Fe-reconstituted enzyme was inactivated by 10 mM hydrogen peroxide to about 5% of its original activity after a 15 min incubation at 25 degrees C at pH 7.8, whereas the Mn-reconstituted enzyme showed no inactivation after 80 min. A concomitant increase in absorbance at 320 nm was observed with inactivation of the Fe-reconstituted enzyme. Amino acid analysis of the inactivated Fe-reconstituted enzyme showed a decrease of about 0.7 residues of tryptophan/subunit, a value similar to the iron content of the iron-reconstituted enzyme. Three major peptides of the digests of the purified SOD with lysylendopeptidase were separated by a reverse-phase HPLC monitoring at 280 nm. One of the peptides, corresponding to the residues from Gly149 to Lys176, decreased in the HPLC eluent of the H2O2-inactivated SOD to 20% of the amount measured for native SOD. Since this peptide contains only one tryptophan residue, it was concluded that the decomposed tryptophan residue is Trp159, which is located midway between the third and fourth metal ligands, Asp157 and His161, and is conserved in aligned amino acid sequences of all known Fe-SODs and Mn-SODs. Based on these results, we propose that the differences in hydrogen peroxide sensitivities observed for the Fe-SODs and Mn-SODs may be caused by the difference in the identity of the active site metal in the Fe-SODs and Mn-SODs and a tuning of the properties of the iron center in the Fe-SODs.

Amino Acid Sequence↗
PubMed1998

Effect of monoclonal anti-human gp130 antibody (GPX7) on bone turnover in normal and ovariectomized rats.

We examined the effects of a monoclonal antihuman gp130 antibody (GPX7), which is known to inhibit interleukin-6 (IL-6) and leukemia inhibitory factor-mediated responses in human cells on the bone metabolism in normal and ovariectomized (OVX), 7-month-old, Wistar rats for 8 weeks. After confirming the cross-reactivity of the antibody in suppressing the IL-6-mediated proliferation of rat liver cells, GPX7 was injected once a week at doses of 1 (low dose) or 4 (high dose) mg/kg body weight (BW). In the lumbar body, bone mineral density values and the trabecular bone volume (BV/TV) were maintained in the GPX7 groups. The values of the trabecular osteoclast surface and number in the GPX7 high-dose group were significantly smaller than those in the OVX controls. The double-labeled surface and bone formation rates in the GPX7 high-dose group were significantly increased. In the proximal tibia, however, the bone mineral content and BV/ TV values in the GPX7 groups were smaller, but the trabecular thickness value in the GPX7 high-dose group was larger than in the OVX control. The single-labeled surface in the GPX7 high-dose group was significantly larger than that in the OVX control rats. Though the parameter values of trabecular osteoclasts were apparently smaller, the differences were not significant. 17-beta estradiol (0.125 mg/kg BW a week) administration prevented the bone loss by reducing the parameters of bone formation and resorption in both the lumbar and the proximal tibia. The antibody administration to the normal rats did not cause any significant changes in the parameters of bone mass and turnover. These data demonstrate that while GPX7 modulates the bone turnover after ovariectomy in rats, it does not compensate for the action of estrogen after ovariectomy in rats.

Alkaline Phosphatase↗
PubMed1998

Parallel stimulations of in vitro and in situ [35S]GTPgammaS binding by endomorphin 1 and DAMGO in mouse brains.

Metabotropic activities of endomorphin 1, a candidate for endogenous mu-opioid receptor ligands, were examined in comparison with the actions of [D-Ala2, N-Me-Phe4, Gly5ol]-enkephalin/DAMGO, a well-known synthetic mu-opioid agonist. Endomorphin 1 stimulated [35S]GTPgammaS binding to synaptic membranes from the mouse amygdala in a naloxone-reversible manner. DAMGO had the same effect in such preparations. In in situ [35S]GTP-gammaS binding experiments using brain sections, both endomorphin 1 and DAMGO similarly stimulated this binding in specific cellular locations throughout the brain regions. These findings strongly support the view that endomorphin 1 selectively acts on a mu-opioid receptor.

Amygdala↗
PubMed1998

p-Aminobenzamidine-sensitive acrosomal protease(s) other than acrosin serve the sperm penetration of the egg zona pellucida in mouse.

It has been reported that a significant delay in protein dispersal from the acrosomal matrix is observed in wild-type sperm by adding p-aminobenzamidine, a trypsin/acrosin inhibitor, to the incubation medium. The pattern of this delayed release was similar to that of the acrosin-deficient mutant mouse sperm (Yamagata et al., J. Biol. Chem., 273, 10470-4, 1998). In the present study, no further delay in protein dispersal was found when the acrosin-deficient sperm were treated with p-aminobenzamidine, indicating that among the p-aminobenzamidine-sensitive protease(s) only acrosin may function to accelerate this process. Although the acrosin-deficient sperm penetrated the zona pellucida (Baba et al., J. Biol. Chem., 269, 31845-9, 1994), the addition of p-aminobenzamidine to the fertilisation medium caused a significant inhibition of fertilisation in vitro. This indicates that there is a p-aminobenzamidine-sensitive protease(s) other than acrosin participating in the zona penetration step. Indeed, we demonstrated that a non-acrosin protease with a size of 42 kDa was present in the supernatant of the acrosome-reacted sperm suspension. The enzyme was inhibited by p-aminobenzamidine, diisopropyl fluorophosphate and N alpha-tosyl-L-lysine chloromethyl ketone, and was apparently activated by acrosin.

Acrosin↗
PubMed1998

[Aging of macular function as seen in multifocal electroretinograms].

Multifocal electroretinograms were recorded from 32 eyes of 32 young and aged healthy volunteers to investigate the change in electrophysiological functions with age in the central, nasal, temporal, superior, and inferior retina. The amplitude and latency of the first negative and positive waves were analyzed statistically in correlation with age. In all regions, amplitudes of focal responses tended to diminish with age. There was significant inverse correlation between amplitude and age in the central retina at 2 and 8 degrees, but no significant correlation was found in the other regions. These facts suggest that the macular retina tends to show functional deterioration with age when compared with other retinal areas.

Adolescent↗
PubMed1998

[Apoptotic changes after pressure-induced ischemia-reperfusion injury in the rat retina].

50 eyes of 30 Sprague-Dawley rats were subjected to 60 minutes of pressure-induced ischemia, then fixed for light and electron microscopy with no reperfusion, or reperfusion after 30 minutes, 1, 2 or 4 hours, and 1 or 3 days from the time ocular ischemia was relaxed. The TdT-mediated dUTP-biotin nick end labeling (TUNEL) method revealed apoptotic signs at the inner retina as early as 1 hour after reperfusion. However, the incidence of apoptotic signs with the TUNEL method did not accord with the results of electron microscopic examination. During the time after the reperfusion started, especially after more than 4 hours, apoptotic signs became obvious and extended from the inner to the outer retina. These apoptotic findings could be seen with both the TUNEL method and electron microscopy. By 3 days after the reperfusion, necrotic cells in the ganglion cell layer, and the inner and outer nuclear layer became more prominent than apoptotic cells. These results may provide a baseline for therapeutic strategy and the prognosis of ischemia-reperfusion injury in the retina.

Animals↗