Haematological study of healthy volunteers 5 years after G-CSF.
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Adult↗
Biomedical subjects
T Matsunaga
Publications and source records attributed to T Matsunaga.
An iron-regulated gene, magA, encoding an iron transport protein of Magnetospirillum sp. strain AMB-1.
Magnetospirillum sp. AMB-1 is a freshwater magnetic bacterium which synthesizes intracellular particles of magnetite (Fe3O4). A genomic DNA fragment required for synthesis of magnetic particles was previously isolated from a nonmagnetic transposon Tn5 mutant. We have determined the complete nucleotide sequence of this fragment. The 2975-base pair region contains two putative open reading frames. One open reading frame, designated magA, encodes a polypeptide which is homologous to the cation efflux proteins, the Escherichia coli potassium ion-translocating protein, KefC, and the putative Na+/H(+)-antiporter, NapA, from Enterococcus hirae. Northern hybridization demonstrated that the magA mRNA transcript is 1.3 kilobases in size, corresponding to the size of the magA gene. A functional promoter was located upstream from the magA gene, and the transcription in AMB-1 was regulated by environmental iron concentration. Vesicles isolated from E. coli in which the MagA protein was expressed exhibited iron accumulation ability. We consider that the MagA protein is an iron transport involved in the synthesis of magnetic particles in AMB-1.
Amino Acid Sequence↗
Rapid identification of Streptococcus pneumoniae by PCR amplification of ribosomal DNA spacer region.
Streptococcus pneumoniae is one of the important human pathogens in clinical microbiology. A polymerase chain reaction assay was designed to detect and identify S. pneumoniae through amplification of the ribosomal DNA spacer regions between the pneumococcal 16S-23S ribosomal RNA genes. Thirty-two Streptococcus and non-Streptococcus strains were tested to verify the specificity of the assay, and only S. pneumoniae strains gave a positive reaction. This method is a powerful technique for the rapid identification of S. pneumoniae.
Bacteriological Techniques↗
Purification and characterization of the XPF-ERCC1 complex of human DNA repair excision nuclease.
A complex, which consists of ERCC1 (38 kDa) and a 112-kDa protein, was purified from HeLa cells to homogeneity. This complex complemented the nucleotide excision repair defects of rodent ERCC-1, ERCC-4, and human XP-F mutant cell-free extracts, indicating that the 112-kDa protein is XPF/ERCC4 and providing direct biochemical evidence that XPF and ERCC4 are identical. The XPF/ERCC4-ERCC1 complex has an endonuclease activity with preference for single-stranded DNA and a single-stranded region of duplex DNA with a "bubble" structure. This complex also nicks supercoiled DNA weakly, and this nicking activity is stimulated by human replication protein A when the DNA contains UV damage.
Base Sequence↗
Human DNA repair excision nuclease. Analysis of the roles of the subunits involved in dual incisions by using anti-XPG and anti-ERCC1 antibodies.
Human DNA repair excision nuclease removes DNA damage by incising on both sides of the lesion in a precise manner. The activity requires participation of 16-17 polypeptides. Of these, the XPF.ERCC1 complex and XPG were predicted to carry the nuclease active sites based on studies with the recombinant proteins and the yeast homologs of these proteins. Furthermore, recent work with model (undamaged) substrates have led to predictions of the roles of these proteins in incising 5' or 3' to the lesion. We have used damaged DNA substrates and antibodies to XPG and ERCC1 to test these predictions. Our results reveal that anti-XPG antibodies change the site of 3' incision and at high concentration inhibit the 3' incision without significantly affecting the 5' incision, indicating that XPG makes the 3' incision and further that under this condition 5' incision can occur without 3' incision. In contrast, anti-ERCC1 antibodies inhibit both the 3' and 5' incisions. Using a defined system for excision repair we also demonstrate that the 3' incision can occur without the 5' incision, leading us to conclude that under certain conditions the two incisions can occur independently.
Animals↗
Linear ablation of the isthmus between the inferior vena cava and tricuspid annulus for the treatment of atrial flutter. A study in the canine atrial flutter model.
BACKGROUND: The isthmus between the inferior vena cava and the tricuspid annulus has been shown to be involved in the reentry circuit of common atrial flutter. The effects of radio-frequency catheter ablation of this isthmus were examined in the canine model of atrial flutter due to reentry around the tricuspid annulus. METHODS AND RESULTS: A model of atrial flutter was prepared in 11 of 14 dogs by creating intercaval and connected transverse lesions (Y-shaped lesion). Bipolar electrodes were attached at 24 atrial sites, and computer-assisted mapping was performed. Stable atrial flutter with a cycle length of 133 +/- 11 ms was repeatedly induced by rapid atrial pacing in all dogs, and atrial mapping revealed reentry around the tricuspid annulus including the isthmus. In 6 dogs, the isthmus was ligated during atrial flutter (mechanical ablation). In the other 5 dogs, a 7F large-tip electrode catheter was placed at the isthmus under a fluoroscopic control. Radiofrequency energy (25 W for 30 s) was delivered to three sequential sites from the tricuspid annulus to the inferior vena cava to ablate the isthmus linearly. Atrial flutter was terminated in all dogs after mechanical and radio-frequency ablation of the isthmus and was not induced again. Atrial pacing from the posterior left atrium during sinus rhythm demonstrated intra-atrial conduction block at the isthmus after ablation. Pathological examination of the isthmus showed transmural myocardial damage. CONCLUSIONS: Linear radiofrequency ablation of the isthmus can induce intra-atrial conduction block and is effective as a curative therapy for atrial flutter when the reentry circuit involves the isthmus.
Animals↗
Effect of ultraviolet-A (UV-A) light on growth, photosynthetic activity and production of biopterin glucoside by the marine UV-A resistant cyanobacterium Oscillatoria sp.
We have isolated a marine planktonic cyanobacterium Oscillatoria sp. NKBG 091600 which is resistant to ultraviolet-A (UV-A) irradiation. In response to UV-A irradiation this cyanobacterium produces high levels of a UV-A absorbing compound which was identified previously as biopterin glucoside. Here, we have investigated the effect of UV-A light intensity on growth, biopterin glucoside production and photosynthetic activity. Oscillatoria sp. NKBG 091600 could grow at UV-A intensities of up to 800 microW/cm2 and at 300 microW/cm2 could grow as well as in the absence of UV-A irradiation. In addition, pre-culture of cells with UV-A protected cells from UV-A induced inhibition of photosynthetic activity. Detection of biopterin glucoside levels in irradiated cells by HPLC demonstrated that after 10 h there was a rapid increase in biopterin glucoside content. This increase was dependent on the intensity on the intensity of the UV-A irradiation.
Biopterins↗
Phylogenetic analysis of a novel sulfate-reducing magnetic bacterium, RS-1, demonstrates its membership of the delta-Proteobacteria.
Most of the 16S ribosomal RNA gene of a sulfate-reducing magnetic bacterium, RS-1, was sequenced, and phylogenetic analysis was carried out. The results suggest that RS-1 is a member of the delta-Proteobacteria, and it appears to represent a new genus. RS-1 is the first bacterium reported outside the alpha-Proteobacteria that contains magnetite inclusions. RS-1 therefore disrupts the correlation between the alpha-Proteobacteria and possession of magnetite inclusions, and that between the delta-Proteobacteria and possession of greigite inclusions. The existence of RS-1 also suggests that intracellular magnetite biomineralization is of multiple evolutionary origins.
Bacteria↗
Reconstitution of human DNA repair excision nuclease in a highly defined system.
Xeroderma pigmentosum is a hereditary disease caused by defective DNA repair. Somatic cell genetics and biochemical studies with cell-free extracts indicate that at least 16 polypeptides are required to carry out the repair reaction proper, i.e. the removal of the lesion from the DNA by the dual incisions of the damaged strand. To find out if these proteins are necessary and sufficient for excision repair, they were obtained at a high level of purity in five fractions. The mixture of these five fractions reconstituted the excision nuclease (excinuclease) activity. Using the reconstituted excinuclease, we found that the excised fragment remains associated with the post-incision DNA-protein complex, suggesting that accessory proteins are needed to release the excised oligomer.
Animals↗
A novel drug delivery system for osteomyelitis using porous hydroxyapatite blocks loaded by centrifugation.
A novel drug delivery system for osteomyelitis was developed using porous hydroxyapatite blocks (HA-b) loaded with antibiotics by centrifugation. In the study, 10 mm3 HA-b was placed in a container and mixed with antibiotic solution; the antibiotic was then loaded into the pores of the HA-b by centrifuging at 1500 rpm for 15 min. Slow release of HA-b in both moist form and dried form (by heating at 160 degrees C) was tested after loading with the antibiotic arbekacin sulfate (ABK), 1-N-(S)-4 amino-2-hydroxybutyryl dibekacin. To estimate the concentration of antibiotic, both forms of HA-b were placed in 3 mL of phosphate buffered saline (PBS), which was replaced every 48 h. In both groups, which were loaded with 70 mg ABK per one block of HA (concn 0.5 microgram/mL) which is sufficiently high to control most pathogens, was maintained for 21 exchanges of PBS (after 42 days). Minimum inhibitory concentration for methicillin-resistant Staphylococcus aureus (MRSA), 3.13 micrograms/mL, was maintained until nine exchanges took place (after 18 days). The centrifugation method is simple, and dried ABK produced by heating loaded HA-b is particularly useful in clinical applications for osteomyelitis.
Anti-Bacterial Agents↗
Prednisolone excitation of medial vestibular nucleus neurons in cats.
An electrophysiological study was performed to determine whether prednisolone hydrochloride directly influenced neuronal activities of the medial vestibular nucleus (MVN) in alpha-chloralose-anesthetized cats. Single neuronal activities of MVN were recorded extracellularly with a glass-insulated silver wire microelectrode attached along a seven-barreled micropipette. Each barrel was filled with prednisolone, glutamate, glutamic acid diethylester (GDEE) or CoCl2. Except for prednisolone, which was administered both intravenously and microiontophoretically, other chemicals were applied microiontophoretically to the immediate vicinity of the target neurons. These MVN neurons were classified as type I and II neurons according to their responses to horizontal and sinusoidal rotations. Intravenous prednisolone (up to 5 mg/kg) enhanced spontaneous and rotation-induced neuronal firings of both type I and II neurons in a dose-dependent manner. In a similar tendency, microiontophoretically applied prednisolone (50-200 nA) dose-dependently increased spontaneous and rotation-induced firings of both type I and II neurons. Microiontophoretic GDEE, a non-selective glutamate receptor antagonist, inhibited glutamate- and rotation-induced neuronal discharges without affecting prednisolone-induced increases in neuronal responses of MVN. In addition, iontophoretically applied CoCl2, a Ca2+ channel blocker, did not affect prednisolone-, glutamate- and rotation-induced neuronal findings of MVN. These results suggest that prednisolone induces excitation of type I and II neurons, probably by acting directly on the membrane of MVN neurons. Thus, glucocorticoids such as prednisolone may be effective for the treatment of vertigo resulting from hypofunction of vestibular nucleus neurons.
Animals↗
The action of substance P methyl ester on cochlear potentials in the guinea pig.
The action of the substance P agonist, substance P methyl ester (SPME) on cochlear potentials was examined in the guinea pig. Previous studies have shown that SPME is a selective agonist for neurokinin 1 (NK1) receptor. Perfusion with SPME at a concentration of more than 10(-6)M produced an increase in the amplitudes of the compound action potential and negative summating potential in a dose-dependent manner. N1 latency showed a tendency to be shortened, but this change was not significant. Amplitudes of the cochlear microphonics and endocochlear potential remained unchanged. Substance P fragment 7-11, an inactive analogue, produced no changes in the cochlear potentials. In contrast, the substance P antagonist [D-Pro2, D-Trp7,9]-SP blocked the action of SPME on the cochlear potentials. These results suggest that substance P may modulate neurotransmission through NK1 receptors in the cochlea.
Action Potentials↗
Evolution of the immunoglobulin M constant region genes of salmonid fish, rainbow trout (Oncorhynchus mykiss) and Arctic charr (Salvelinus alpinus): implications concerning divergence time of species.
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Amino Acid Sequence↗
Auditory brainstem response findings in brainstem ischemia following selective occlusion of the anterior inferior cerebellar artery in the rat.
Auditory brainstem responses (ABRs) were measured ipsilaterally (n = 13) or contralaterally (n = 5) after inducing permanent right and left anterior inferior cerebellar artery (AICA) occlusion. Three types of wave patterns were classified when ABRs were recorded ipsilaterally. In type 1 (n = 4) all components disappeared; in type 2 (n = 2) all components disappeared transiently and then reappeared; and in type 3 (n = 7) only the latency difference between components I and IV increased. These findings indicate that all components reappeared in type 2 responses because cochlear blood flow was re-established quickly by collateral circulation, while type 3 changes reflected the relative sensitivity of the cochlea to ischemic damage when compared with the rest of the auditory pathways. When the ABRs were recorded contralaterally, characteristic findings included a delay in latency of component IV and a significant increase in inter-peak latency in components I-IV and IIb-IV.
Animals↗
Evolution of immunoglobulin heavy chain variable region genes: a VH family can last for 150-200 million years or longer.
Many immunoglobulin variable region (IgV) genes are present in the vertebrate genome and provide a basis for antibody diversity. IgV genes have been classified into distinct families according to DNA sequence similarity. Comparisons of VH and VL genes from two mammalian species (mouse and human) have led to the conclusion that some V gene families are stable over 65 million years of evolution. Here we show that a VH family can be stable for 150-200 million years or longer. This conclusion is drawn from our extensive comparison of VH genes between two species of low vertebrates (rainbow trout and catfish), and from the estimation of species divergence time by the substitution rate of an IgM constant domain. The estimated speed of VH gene evolution explains the moderate degree of sequence similarity in VH gene families between a mammal (mouse) and a teleost (rainbow trout). The distribution of species-specific amino acid residues in certain VH families indicates that the process of sequence homogenization plays a major role in shaping the V gene family.
Amino Acid Sequence↗
Histochemical differences of the lectin affinities of backbone polylactosamine structures carrying the ABO blood group antigens in papillary carcinoma and other types of thyroid neoplasm.
Endo-beta-galactosidase from Escherichia freundii cleaves linear polylactosamine structure as follows: R-GlcNAc-beta 1-3Gal-beta 1-4GlcNAc-beta 1-R' + H2O-->R-GlcNAc-beta 1-3Gal + GlcNAc-beta 1-R'. Staining with Griffonia simplicifolia agglutinin II (GSA-II) following enzyme digestion reveals the distribution of R-GlcNac-beta 1-3Gal-beta 1-4GlcNAc-beta 1-R' structures in tissue sections. In this study, the procedure was applied to formalin-fixed, paraffin-embedded tissue sections from 26 cases of papillary carcinomas including 2 follicular variants, 8 follicular carcinomas, 7 adenomas, 1 anaplastic carcinoma and 1 medullary carcinoma in order to investigate whether different types of polyactosamine-containing structure are produced in these thyroid neoplasms. Simultaneously, the susceptibility of the ABH antigens expressed in these neoplastic cells to endo-beta-galactosidase digestion was examined. Most of the papillary carcinoma cells from all the individuals examined were strongly stained by GSA-II following enzyme digestion. Without enzyme digestion, little or no reactivity with GSA-II was observed. Among other types of neoplasms, only one case of follicular carcinoma exhibited reactivity with GSA-II following enzyme digestion. ABH antigens were expressed in 22 cases of papillary carcinomas, 2 adenomas, 5 follicular carcinomas and 1 anaplastic carcinoma, and their expression was dependent on the ABO blood group of the patients. Endo-beta-galactosidase digestion resulted in the elimination of these antigens not only in papillary carcinomas but also in other neoplasms.(ABSTRACT TRUNCATED AT 250 WORDS)
ABO Blood-Group System↗
Metabolism of delta 9-tetrahydrocannabinol by cytochrome P450 isozymes purified from hepatic microsomes of monkeys.
The most abundant metabolite of delta 9-tetrahydrocannabinol (delta 9-THC) formed with hepatic microsomes of monkeys was 11-OH-delta 9-THC, followed by 8 alpha-OH-, 8 beta-OH- and 3'-OH-delta 9-THCs. Two cytochrome P450 isozymes, P450RM-A and P450JM-C, were purified from monkey hepatic microsomes and found to have a molecular weight of 51,000. In the reconstituted system, the activities of P450RM-A towards formation of 11-OH-, 8 alpha-OH-, 8 beta-OH- and 3'-OH-delta 9-THCs were 19-, 40-, 22- and 10-fold higher, respectively, than the corresponding activities of the hepatic microsomes. The activity of P450JM-C towards formation of 3'-OH-delta 9-THC was 10-fold higher than that of P450RM-A, while the activities of both isozymes for 11- and 8 alpha-hydroxylation were not so much different and the 8 beta-hydroxylation activity was 14-fold higher in P450RM-A than in P450JM-C. Antibodies against P450RM-A and P450JM-C markedly inhibited the microsomal formation of 11-OH- and 8 alpha-OH-delta 9-THCs, and 3'-OH-delta 9-THC, respectively. These results suggest that P450RM-A and P450JM-C are major isozymes responsible for the formation of 11-OH- and 8 alpha-OH-delta 9-THCs, and 3'-OH-delta 9-THC, respectively, in monkeys.
Amino Acid Sequence↗
Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.
To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗