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Biomedical subjects

M Moriya

Publications and source records attributed to M Moriya.

At least 55 records · Page 3Linked to original sources
PubMed1995

Bulbar morphology and expression of bulbar dopamine and parvalbumin in experimentally-induced anosmic rats.

Morphological study was carried out in rats with olfactory dysfunction induced by deafferentation of serotonergic fibers in the olfactory bulb. With a computer capable of area measurements, olfactory bulbs of the anosmic rats were found to be decreased in size to 61% of control bulbs, and all bulbar layers were involved in the bulbar shrinkage. Given areas of each bulbar layer in control bulbs to be 100%, percentages of each bulbar layer in the anosmic rats were 23% in the olfactory nerve layer, 54% in the glomerular layer, 63% in the external plexiform layer, 83% in the internal plexiform layer and 81% in the granule cell layer. Dopamine-and parvalbumin-containing neurons were examined immunohistochemically in the experimentally-induced anosmic rats. As a result, immunoreactive neurons for these two chemical substances were significantly decreased in number (dopamine, 33% of control value; parvalbumin, 46% of control value). The present study, using an animal model of anosmia, provided quantitative data on the bulbar atrophy and showed effects of anosmia on expression of dopamine and parvalbumin in the bulb.

Animals↗
PubMed1995

Effects of ranitidine on gastric vesicles containing H+,K(+)-adenosine triphosphatase in rats.

BACKGROUND: To ascertain the mechanism for rebound acid hypersecretion after treatment with an H2-receptor blocker, we investigated the effects of ranitidine on gastric H+,K(+)-adenosine triphosphatase (ATPase) in rats. METHODS: Male Wistar rats received ranitidine (1-50 mg/kg body weight intraperitoneally twice a day for 5 days). The rats were starved for 15 h after the last treatment and then killed, and gastric vesicles containing H+,K(+)-ATPase were prepared. RESULTS: Treatment with ranitidine dose-dependently increased protein content in the gastric vesicular fraction purified from the gastric mucosa without changing total protein content. Ranitidine also increased the content of a 94,000-dalton protein, the catalytic subunit of H+,K(+)-ATPase. On the other hand, ranitidine did not affect the specific activity of the enzyme (mumol/min/mg of the gastric vesicular protein). Since gastric vesicles in the fasting state mainly consist of the tubulovesicular membrane, these results suggest that ranidine administration increases total tubulovesicular H+,K(+)-ATPase content (mumol/min/rat) by increasing the number of tubulovesicles per parietal cell. The ranitidine-induced increase in total tubulovesicular H+,K(+)-ATPase activity was still evident 1 week after treatment and returned to control level 1 month later. CONCLUSIONS: All these findings suggest that the increased content and total activity of tubulovesicular H+,K(+)-ATPase after ranitidine treatment may contribute to the mechanism for acid rebound after H2-blocker therapy.

Animals↗
PubMed1994

Mutagenic potency of exocyclic DNA adducts: marked differences between Escherichia coli and simian kidney cells.

A single-stranded shuttle vector containing a single 3,N4-etheno-2'-deoxycytidine (epsilon dC) or 1,N2-(1,3-propano)-2'- deoxyguanosine (PdG) DNA adduct was used to investigate translesional DNA synthesis in Escherichia coli and simian kidney (COS) cells. The presence of either exocyclic adduct was associated with reduced numbers of transformants. In E. coli, this inhibitory effect could be overcome partially by irradiating cells with UV light before transformation. Translesional synthesis past both exocyclic lesions was accompanied by targeted mutations. For PdG, the primary mutagenic events observed in both hosts were PdG-->T transversions; in preirradiated E. coli, PdG-->A transitions were also observed. The targeted mutation frequency for single-stranded DNA that contained PdG was 100% in nonirradiated E. coli, 68% in preirradiated cells, and 8% in COS cells. In contrast, the targeted mutation frequency for single-stranded DNA that contained epsilon dC was 2% in nonirradiated E. coli, 32% in preirradiated cells, and 81% in COS cells. The primary mutations generated by epsilon dC in both E. coli and COS cells were epsilon dC-->A and epsilon dC-->T base substitutions. These observations appear to reflect the variable specificity of DNA replication complexes in incorporating bases opposite certain adducts. We conclude that DNA synthesis past the same DNA adduct can have strikingly different consequences in bacteria and mammalian cells, underscoring the importance of establishing the intrinsic mutagenic potential of DNA adducts in mammalian cells.

Animals↗
PubMed1994

Prominent expression of protein kinase C (gamma) mRNA in the dendrite-rich neuropil of mice cerebellum at the critical period for synaptogenesis.

It has been suggested that the expression of type 1 (gamma) protein kinase C(PKC) plays an active role in synaptogenesis. In situ hybridization assisted by an original computer image analysis technique (superimposition method) enabled the identification of PKC mRNA expression in the dendrite-rich neuropil area of the cerebellum. This study revealed prominent expression of PKC mRNA in the dendrite-rich neuropil area of the cerebellum at the critical period for synaptogenesis compared with adult mice cerebellum. Therefore, it is suggested that PKC mRNA in the dendrites of Purkinje cells plays an important role in synaptogenesis.

Algorithms↗
PubMed1994

Lipid interference with fluorometric assay of DNA in adipose tissues under various conditions.

Interference by lipids with fluorometric assay of DNA in adipose tissues using Hoechst 33258 was investigated. Mixed glycerides shifted the emission maximum of standard DNA and induced a dose-dependent increase in fluorescence intensity. Glycerides in the samples containing a known concentration of DNA yielded erroneously higher DNA concentrations. The DNA concentrations obtained from acetone-defatted white and brown adipose tissues (WAT and BAT) were lower than those of non-defatted ones, while DNA content did not differ in low lipid-containing skeletal muscle between defatted and non-defatted samples, indicating that large amounts of lipids interfere with DNA measurement using Hoechst 33258 and that acetone defatting is a simple method to avoid this interference. Using this defatting method, the cellularity of WAT and BAT was estimated in rats under various experimental conditions. Cold-acclimation and repetitive immobilization stress decreased the body weight gain and the epididymal WAT weight. Sucrose overfeeding increased WAT weight but not body weight. These treatments of 4 weeks' duration did not induce any significant difference in WAT cell number from controls, while cold-acclimation increased the tissue cell number as well as the BAT weight.

Acetone↗
PubMed1994

A new computer analysis technique using automatic threshold selection algorithm, available for quantitative estimation of the immunostained dendrites of the cerebellum.

We developed a new computer image analysis technique with application of an automatic threshold selection (ATS) algorithm which was successfully used in the quantitative evaluation of a highly complex texture of immunostained brain tissue. We applied this new method for estimation of the volume of the Purkinje dendrites, which were immunohistochemically stained for inositol 1,4,5-trisphosphate receptor protein (P400), and demonstrated a significant reduction of the dendritic arborization of the Purkinje cells of a neurological mutant mouse. Wriggle mouse Sagami, which would appear normal if stained with conventional methods such as H-E and Nissle staining.

Algorithms↗
PubMed1994

[Nutritional adaptation in brown adipose tissue thermogenesis--with special reference to overfeeding and iron deficiency].

The effect of sucrose overfeeding and low iron diet on brown adipose tissue (BAT) thermogenesis of rats has been investigated from the view point of in vitro BAT oxygen consumption and BAT fatty acids (FA) compositions in rats. Control group was fed on a standard diet with tap water, sucrose group was on the standard diet and 32% sucrose solution, and iron deficient group on a low iron diet with tap water. In vitro interscapular BAT thermogenesis as estimated by oxygen consumption was measured in minced tissue blocks in Krebs-Ringer phosphate buffer using a Clark oxygen electrode. In sucrose overfeeding rats, caloric intake was greater than in controls, but did not differ body weight. Interscapular BAT weight and DNA content were greater. Colonic and tail skin temperatures were higher. Basal oxygen consumption was higher. Noradrenaline- and glucagon-stimulated oxygen consumptions did not differ when expressed per DNA, but significantly greater per whole tissue pad. Both BAT-triglyceride (TG) and -phospholipid (PL) levels were higher. Polyunsaturated FA were lower, while monosaturated FA were higher in both BAT-TG and -PL. In iron deficient rats, BAT weight and DNA content were higher. Colonic and tail skin temperatures did not differ. Although basal oxygen consumption did not differ, noradrenaline-stimulated oxygen consumption was less per DNA, but did not differ per whole tissue pad, while glucagon-stimulated oxygen consumption was less when expressed per DNA, as well as whole tissue pad. Cold-tolerance as assessed by the fall in colonic temperature at 0 degree C was decreased. BAT-TG and -PL levels did not differ. Polyunsaturated FA were higher in both BAT-TG and -PL. These findings indicated that sucrose-induced overfeeding enhances BAT thermogenesis mainly by tissue hyperplasia, while iron deficiency suppresses BAT thermogenic response, although it causes the compensatory tissue hyperplasia.

Adaptation, Physiological↗
PubMed1994

Studies on the inferior phrenic vein of rats: the probability of its being a collateral route of blood from the lower portion of the body to the heart.

The principal aim of this study was to elucidate key features of the inferior phrenic vein (IPV) of adult rats to determine whether the IPV has the potential to function as a collateral return route conveying blood from the lower portion of the body to the heart, bypassing the subhepatic vein segment of the inferior caval vein. In rats, the IPVs on both sides were found to reveal a symmetric appearance. They were both composite vessels, being made up of two fellow subvessels, the sternocostal and the lumbocostal veins, which in turn anastomosed in tandem in their periphery with each other, formed a collateral route bridging the interval between the suprarenal and the hepatic vein segments of the inferior caval vein. In rat embryos of E17.5, the sternocostal and lumbocostal veins of the IPV were observed to have been well developed, forming tandem anastomoses more clearly than in adults, thus connecting the subcardinal vein to the hepatic vein segment of the inferior caval vein. This fact substantiates our supposition that the rat's IPV originally has the potential to act as a collateral returning route which allows blood to bypass the subhepatic vein segment of the inferior caval vein.

Animals↗
PubMed1993

Single-stranded shuttle phagemid for mutagenesis studies in mammalian cells: 8-oxoguanine in DNA induces targeted G.C-->T.A transversions in simian kidney cells.

A single-stranded shuttle vector has been developed for the purpose of investigating translesional events in mammalian cells. The vector is designed to permit site-specific introduction of defined DNA lesions between a gene for neomycin resistance and its promoter. Efficiencies of translesional synthesis in simian kidney cells (COS) and Escherichia coli are established by determining the number of neomycin- and ampicillin-resistant colonies recovered, respectively, after introduction of a modified vector. Fidelity of translesional synthesis is evaluated by analyzing the nucleotide sequence of progeny phagemid DNA in the region corresponding to the lesion site. This experimental system, capable of detecting mutagenic and nonmutagenic events at and adjacent to the lesion site, was used to establish the mutagenic potential of a single 8-oxoguanine residue in DNA. This modified base, produced by attack of reactive oxygen species on cellular DNA, did not cause a decrease in the number of transformants when single-stranded DNA containing the lesion replicated in COS cells or E. coli. The predominant mutations observed (> 78%) were G-->T transversions targeted to the site of the lesion. The mutation frequencies for this event were 2.5-4.8% in COS cells and 1.8% in E. coli. It is concluded that a single-stranded shuttle vector, utilized in conjunction with a site-specific approach, can be used to investigate translesional events in mammalian cells and in bacteria.

Adamantane↗
PubMed1993

An endoplasmic reticulum protein, calreticulin, is transported into the acrosome of rat sperm.

Recently, we purified a Ca(2+)-binding protein from rat spermatogenic cells [Biochem. Biophys. Res. Commun. 176, 135-1364, 1991]. In the present study, this protein was identified as calreticulin, which is a resident protein of the endoplasmic reticulum (ER). Immunohistochemical studies revealed that calreticulin was present in the acrosome of both round spermatids and mature sperm. However, under immunoelectron microscopy, gold-particles were seen over other subcellular structures of spermatocytes, spermatids, and Sertoli cells. When the labeling density in subcellular structures of spermatids was analyzed, the acrosome was found to be most heavily labeled and the Golgi apparatus was second. The complete amino acid sequence of calreticulin, deduced from the cDNA sequence, shares a high degree of identity with that of the analogous mouse protein. The cDNA encoded a protein of 416 amino acids, including a 17-residue NH2-terminal signal sequence. The mature protein contains a KDEL sequence as an ER signal at the COOH terminus. Sperm calreticulin contained no glycosyl moiety. Northern blot analysis of RNAs from purified populations of rat spermatogenic cells indicated that the calreticulin mRNA was present in both pre- and postmeiotic cells. Immunoblot analysis of calreticulin during developmental stages showed that calreticulin was detected in the testis between the ages of 5 and 50 days. Furthermore, purified rat calreticulin contained two Ca(2+)-binding sites, a low affinity/high capacity site and a high affinity/low capacity site. These results suggest that calreticulin, which is not specific to testis, is closely associated with spermatogenesis of rats. This ER protein may be incorporated into the acrosomal vesicle via the Golgi apparatus, without glycosylation, during spermiogenesis, and may play an important role in the regulation of cell functions such as sperm motility and acrosome reaction.

Acrosome↗
PubMed1993

Mutations in the mutY gene of Escherichia coli enhance the frequency of targeted G:C-->T:a transversions induced by a single 8-oxoguanine residue in single-stranded DNA.

Oxidative damage to guanine in DNA results in the formation of 8-oxoguanine, which has been shown to induce G-->T transversions targeted to this site. The mutagenicity of this lesion was studied in several mutator strains of Escherichia coli, using single-stranded DNA containing a single 8-oxoguanine residue. The frequencies of targeted G-->T transversions increased markedly in mutY strains, while this mutagenic event was not affected in mutM or mutS strains. Introduction of a mutM mutation into a mutY strain caused a somewhat higher frequency of G-->T transversions than that in the mutY strain and the effect of a mutS mutation was marginal. We conclude that the mutY gene plays a crucial role in preventing targeted G-->T mutations derived from misreplication of the 8-oxoguanine-containing template DNA.

Base Sequence↗
PubMed1993

Immuno-electron microscopic localization of calmodulin and calmodulin-binding proteins in the mouse germ cells during spermatogenesis and maturation.

When extracts of mouse testis were Western-blotted against a monoclonal antibody which reacts with calmodulin in the presence of Ca2+, all calmodulin was associated with the macromolecules of molecular weight above 50 kDa. Immuno-electron microscopy of testes using this antibody indicated that calmodulin is localized at higher density in the nucleus and cytoplasm of germ cells during the developmental phase between pachytene and round spermatid, showing the highest level just before meiotic divisions. There was no special association of calmodulin to any organelles in these cells. Extremely low levels of calmodulin occurred in spermatogonia and other testicular tissue cells. Calmodulin decreased dramatically as spermatids underwent metamorphosis, becoming detectable only at the perinuclear space of sperm heads. Further relocation to the postacrosomal region occurred during sperm transit to the cauda epididymis. Immunodetection after the calmodulin overlay on ultrathin sections revealed a sharp increase of calmodulin immunogold deposits in the nuclei of spermatids accompanying their condensation. The results indicate that some calmodulin-binding proteins, but not calmodulin itself, accumulate in the nuclei during the final steps of spermiogenesis.

Animals↗
PubMed1993

Mutagenesis by 8-oxoguanine: an enemy within.

The presence of reactive oxygen species in cells ensures that the oxidatively damaged base 8-oxoguanine will be generated at high frequency in the DNA of all living organisms. DNA damage threatens genomic integrity: enzymes have evolved that protect prokaryotes and eukaryotes from the mutagenic effect of this ubiquitous lesion.

DNA Damage↗
PubMed1993

Analysis of object motion in the ventral part of the medial superior temporal area of the macaque visual cortex.

1. The medial superior temporal area (MST) is an extrastriate area of the macaque visual cortex. Cells in MST have large receptive fields and respond to moving stimuli with directional selectivity. We previously suggested that the dorsal part of MST is mainly involved in analysis of field motion caused by movements of the animal itself, because most cells in the dorsal part preferentially responded to movements of a wide textured field rather than to movements of a small stimulus. To determine whether the remaining ventral part of MST differs in function from the dorsal part, we examined properties of cells in the ventral part in comparison with those of cells in the dorsal part, using anesthetized and paralyzed preparation. 2. Most cells in the ventral part preferably responded to movements of a small stimulus rather than to movements of a wide textured field. 3. Although the cells in the ventral part did not respond to movements of a textured field over a large window, many of them began to respond when a small stationary object was introduced in front of the moving field. The direction to which the cells responded in this stimulus configuration was opposite to the direction in which they responded to movements of an object on a stationary background. Activities of these cells thus represented the direction of relative movement of an object on a background, irrespective of whether the image of the object or the background moved on the retina. 4. We conclude that the ventral part of MST is distinctive from the dorsal part of MST and is mainly involved in the analysis of object movements in external space.

Animals↗
PubMed1993

[Cholecystolithiasis and choledocholithiasis cured by methyl tert butyl ether (MTBE) combined with EST].

A 70-year old male patient was admitted to hospital with fever and right upper quadrant pain. Ultrasonography and cholecystography revealed acute cholecystitis associated with multiple stones not only in the gallbladder but also in the common bile duct. Percutaneous trans-gallbladder drainage (PTGBD) was performed because of his persisting complaints and severe inflammatory change of the gallbladder. Operation was not considered due to his cardiac problem, so we tried direct dissolution treatment of the gallstones by using Methyl tert butyl ether (MTBE) through the percutaneous transhepatic catheter. Following maximal aspiration of the gallbladder contents, same amount of MTBE was infused into and the patient was kept in the right-side-down position for an hour. After 30 times of MTBE treatment, all stones in the gallbladder were thoroughly dissolved without any side effect. A residual stone in the common bile duct was easily taken out by endoscopic sphincterotomy.

Aged↗