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Y Ninomiya

Publications and source records attributed to Y Ninomiya.

At least 289 records · Page 16Linked to original sources
PubMed1985

Activation of collagen synthesis in primary culture of rat liver parenchymal cells (hepatocytes).

An increase in collagen synthesis by hepatic parenchymal cells (hepatocytes) was observed during 8 days in primary culture by the quantification of total [3H]hydroxyproline as a marker of total collagen synthesis and the ratio of [3H]hydroxyproline in the high-molecular-weight fraction to total [3H]hydroxyproline as a marker of collagen degradation after incubation of the cells with [3H]proline for 24 h. Type analysis of the collagen produced by the cells after 8 days in culture showed the presence of type I and type III collagens in addition to the components corresponding to type IV and type V (alpha A and alpha B) collagens. Only the latter two types were found in the collagens produced by the cells after 2 days in primary culture. The purity of the hepatocytes inoculated was 97%, and the majority of the contaminating small cells were erythrocytes. The rate of serum albumin synthesis, which is a typical function of the hepatocytes, was constant or increased during the culture period. Immuno-electron microscopic observation indicated the production of type I collagen by the hepatocytes after 8 days in primary culture. These results are explained only by the activation of collagen synthesis in the day-8 hepatocytes in primary culture.

Animals↗
PubMed1985

A distinct class of vertebrate collagen genes encodes chicken type IX collagen polypeptides.

Type IX collagen is a disulfide-bonded protein first isolated from hyaline cartilage. The structure of this collagen is unusual in that the molecules contain three triple-helical domains interspersed with noncollagenous regions. The molecules are heterotrimers composed of three genetically distinct polypeptide chains. In our laboratory, cDNAs specific for two of these polypeptide chains have recently been isolated. Here we report on the isolation of genomic clones by use of these cDNAs as probes for screening a chicken genomic library. Nucleotide sequence analysis of these clones shows that the exon structure of type IX collagen genes is fundamentally different from the exon structure of the genes for the fibrillar collagen types I-III. Whereas the sizes of exons in fibrillar collagen genes are related to a basic 54-base-pair coding unit, the exons of type IX collagen genes show a large variation in size and do not appear to be related to a 54-base-pair unit. We propose, therefore, that type IX collagen genes belong to a class of vertebrate collagen genes distinct from that of fibrillar collagens.

Amino Acid Sequence↗
PubMed1985

Comparative studies on the modes of action of the antirhinovirus agents Ro 09-0410, Ro 09-0179, RMI-15,731, 4',6-dichloroflavan, and enviroxime.

Modes of action of five antirhinovirus agents were compared. Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 were active preferentially against human rhinovirus. Serotypes of the virus varied in their susceptibility to these three agents, whereas Ro 09-0179 and enviroxime showed activity against all the serotypes of the virus tested to date. Ro 09-0410, RMI-15,731, and 4',6-dichloroflavan inactivated the virus directly, although 4',6-dichloroflavan did so only slightly. Inactivation by 4',6-dichloroflavan and RMI-15,731 was associated with the binding of the agents to the virus, since the infectivity, reduced by exposure to the agents, was restored to the original level by extraction of the agents with chloroform. The binding of [3H]Ro 09-0410 to human rhinovirus type 2 was inhibited by unlabeled Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 but not by Ro 09-0179 or enviroxime. Furthermore, subtypes resistant to both 4',6-dichloroflavan and RMI-15,731 showed cross-resistance to Ro 09-0410 and vice versa. On the other hand, sublines resistant to these three agents were not cross-resistant to Ro 09-0179 or enviroxime. These results indicate (i) that Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 exert their activities through the same mode of action, namely, binding to or interaction with some specific site on the viral capsid protein, and (ii) that the binding or interaction sites for these three agents are either the same or very close to each other.

Antiviral Agents↗
PubMed1984

Qualitative discrimination of gustatory stimuli in three different strains of mice.

Qualitative similarities and differences among various taste stimuli were examined by comparing the generalization patterns of a conditioned aversion from single chemicals to other compounds in 3 different strains of mice (BALB, C3H and C57BL mice). It was observed as a common characteristic in all 3 strains of mice that generalization gradients among sugars and saccharin Na appeared in the order sucrose--saccharin Na--fructose--glucose--maltose, in which the closer stimuli generalized more strongly to each other. Strain differences were found in sensitivities to D-phenylalanine and L-proline, which generalized to sugars and saccharin Na in C57BL mice, but not in BALB and C3H mice. These strain differences correspond quite well to those previously observed in the responses of single chorda tympani fibers to these amino acids in the 3 strains of mice. A hierarchical cluster analysis and a multidimensional scaling analysis showed that 15 compounds including the 4 basic taste stimuli (sucrose, NaCl, HCl and quinine-HCl) were classified into 7 different groups according to their behavioral similarities and some amino acids were not grouped with any of the 4 basic taste stimuli in the 3 strains of mice. These results suggest the possibility that mice perceive tastes of these amino acids in a way different from human taste primaries.

Animals↗
PubMed1984

Gustatory neural responses in three different strains of mice.

Taste sensitivity in mice and its strain variation were studied by examining integrated responses and single fiber discharges of the chorda tympani nerve to various taste stimuli in the 3 different strains of mice (BALB, C3H and C57BL mice). A comparison among integrated responses of the 3 strains demonstrated that C57BL mice possess the highest sensitivity to sucrose and the lowest to acids, whereas the opposite is true for BALB mice. These 3 strains of mice commonly possess higher sensitivity to divalent chloride salts than to NaCl. Measures of the breadth of responsiveness showed that single fibers of all 3 strains of mice are relatively more narrowly tuned to taste stimuli than those of rats and hamsters, although the specificity of fibers tends to be greater in the order of C57BL greater than C3H greater than BALB mice. A cluster analysis of fibers demonstrated that two distinct fiber types, a sweet- and Na-type, commonly exist in all 3 strains of mice. The most clear strain difference was found in the sensitivity to D-phenylalanine, which produced good responses in 'sweet-type' fibers of C57BL mice but not in those of C3H and BALB mice. This suggests the possibility that D-phenylalanine has a taste to C57BL mice that is similar to that of sucrose and that it tastes different to C3H and BALB mice.

Animals↗
PubMed1984

Antivirus agent, Ro 09-0410, binds to rhinovirus specifically and stabilizes the virus conformation.

The antiviral mechanisms of Ro 09-0410 (4'-ethoxy-2'-hydroxy-4,6'-dimethoxychalcone), which inactivates rhinovirus exclusively, have been investigated. It was suggested that Ro 09-0410 bound to human rhinovirus type 2 (HRV-2) and made it inactive, since the reduced infectivity was completely restored to original levels by extraction of the agent with chloroform [H. Ishitsuka, Y. Ninomiya, C. Ohsawa, M. Fujiu, and Y. Suhara (1982) Antimicrob. Agents Chemother. 22, 617-621]. This was confirmed using radioactively labeled Ro 09-0410 and HRV-2. HRV-2 was inactive while bound to the agent, whereas a subline of HRV-2 resistant to the agent had no binding site for the agent. Ro 09-0410 appeared to bind to some specific site(s) on the virion of susceptible virus strains. Treatment of rhinovirus at pH 5 or 56 degrees caused a change of the virion size and greatly reduced its infectivity. Ro 09-0410 could no longer bind to HRV-2 after such treatment. On the other hand, when the virion bound with Ro 09-0410 was treated at pH 5 or 56 degrees, the Ro 09-0410 remained bound and the conformational alteration of the virion did not take place. Furthermore, Ro 09-0410 protected HRV-2 from the reduction of infectivity caused by mild acid or heat treatment, as revealed by infectivity measurements after extraction of the agent with chloroform. These results suggest that Ro 09-0410 binds to the HRV-2 virion and prevents viral replication in the cell.

Antiviral Agents↗
PubMed1984

Synthesis and characterization of cDNA encoding a cartilage-specific short collagen.

Hyaline cartilage contains a unique set of collagenous proteins. Type II collagen is the most abundant, constituting about 85% of the total cartilage collagen. In addition, several minor collagenous components have been described. To study the structure and developmental regulation of chondrocyte-specific collagens, we have constructed a cDNA library from embryonic chicken sternal cartilage mRNA. We report here on the isolation and characterization of a 3200 base-pair-long cDNA that codes for a collagenous polypeptide of unusual structure in that the total length of the molecule is only about half of pro alpha 1(II) collagen chains. The mRNA for this polypeptide is considerably smaller than mRNA encoding the pro alpha chains of interstitial collagens. In addition, the peptide encoded by the cDNA appears to contain at least three domains with triple-helical potential separated by short, noncollagenous peptides. Between the three collagenous domains are several cysteinyl residues.

Amino Acid Sequence↗
PubMed1984

Hepatocytes (hepatic parenchymal cells) produce a major part of liver collagen in vivo.

Following intraperitoneal injection of [3H]proline and colchicine, rat liver cells were dispersed by collagenase perfusion and fractionated by low-speed and density gradient centrifugation. Analysis of the collagenous components using purified bacterial collagenase showed that 0.1 to 0.2% of the labeled protein produced by the liver cells was collagen. Considering the population of the hepatocytes in the liver (70%), 80% of the collagen produced by the liver could be attributed to the hepatocytes.

Animals↗
PubMed1984

Decrease in L-type pyruvate kinase activity in rat liver by some promoters of hepatocarcinogenesis.

A probably promoter-specific decrease of L-type pyruvate kinase (L-PK) in Wistar rat liver is described. The possibility of utilizing the decrease in L-PK activity for screening of hepatic promoters is discussed. A significantly decreased level of activity of L-PK was observed during continuous feedings of the hepatocarcinogen 3'-methyl-4-dimethylaminoazobenzene [(3'-MeDAB) CAS: 55-80-1], which initiates and promotes hepatocarcinogenesis, and of the known hepatic promoters phenobarbital [(PB) CAS: 50-06-6] and dichlorodiphenyltrichloroethane (CAS: 50-29-3) for at least 4 weeks. In contrast, if it occurred, the decrease in L-PK activity by the nonpromoting agents amobarbital (CAS: 57-43-2) and diphenylhydantoin. (CAS: 57-41-0) was temporary and almost overcome by the 4th week. The depression of L-PK activity caused by PB was reversible, was inversely correlated with PB concentration in the diet, and seemed to be organ-specific. Although hepatic promoters lowered L-PK activity in this study, data are so limited that a much more extensive study is necessary before a general conclusion can be drawn. In contrast to L-PK activity, the activity of K-type pyruvate kinase (K-PK) was induced by injections of the carcinogen diethylnitrosamine (CAS: 55-18-5) or the hepatotoxin CCl4 (CAS: 56-23-5) or by the feeding of 3'-MeDAB. However, feeding of PB or 2-methyl-4-dimethylaminoazobenzene (CAS: 54-88-6), which initiates but does not promote hepatocarcinogenesis, did not increase K-PK activity.

Animals↗
PubMed1984

Evaluation of a histologic classification of mouse liver tumors based on pyruvate kinase isozymes and status of host lipids.

The histologic classification of mouse liver tumors, i.e., hepatic nodules type 1 and type 2 and hepatocellular carcinomas, was evaluated by a comparison of several biologic and biochemical markers that have been shown to be useful for the grading of tumor malignancy. The liver tumors were induced by N,N'-2,7-fluorenylenebisacetamide (CAS: 304-28-9; N,N'-fluoren-2,7-ylenebisacetamide) administration to male CD-1 mice. The ability to induce L-type pyruvate kinase activity in response to a high-carbohydrate diet disappeared in almost all the liver tumors. However, fairly good correlations were observed between the histologic classification and the relative weights of liver and intraperitoneal fat pads, between the histologic classification and the level of serum total cholesterol, and between the histologic classification and the K-type pyruvate kinase activity. The results suggest that the present histologic classification reflects the degree of tumor malignancy, and therefore, it would be useful for the classification of mouse liver tumors.

Animals↗
PubMed1983

Relations between the spontaneous firing rate and taste responsiveness of the dog cortical neurons.

The breadth of responsiveness and the spontaneous discharge rates of dog cortical neurons to 4 taste stimuli (NaCl, tartaric acid, sucrose and quinine-HCl) were examined and compared to thalamic neurons. Spontaneous rates were higher in the cortex, and there was a smaller breadth of responsiveness. There were common tendencies observed in both thalamus and cortex; more narrowly tuned taste neurons and neurons having inhibitory responses had higher spontaneous rates. However, as shown by across-neuron correlations, the ability of cortical neurons to discriminate among the 4 tastes was less influenced by the level of spontaneous activity than thalamic neurons.

Animals↗
PubMed1983

The sweetness-inducing effect of miraculin; behavioural and neurophysiological experiments in the rhesus monkey Macaca mulatta.

1. The gustatory effects of miraculin, the sweetness-inducing protein from the miracle fruit Synsepalum dulcificum, was studied in the rhesus monkey, Macaca mulatta.2. The intake of five acids was recorded in two-bottle preference tests, one bottle containing acid and the other tap water, before and after miraculin treatment. All the acids tasted more pleasant after miraculin.3. The electrical activity of the chorda tympani nerve to stimulation of the tongue with a variety of sweeteners, acids, sodium chloride and quinine hydrochloride was recorded in anaesthetized animals.4. Pre-treatment of the tongue with 0.3-5 mg miraculin doubled the summated nerve response to the acids and diminished the response to sucrose by about 10%. The enhancement lasted for at least an hour and the diminution up to 20 min.5. After miraculin treatment the Spearman's rank correlation coefficient between the order of increased intake of acids and the order of enhancement of the summated nerve response was 0.99.6. A solution of 0.1 mg miraculin per ml. elicited a weak nerve response. No preference over water for this concentration of miraculin was recorded in the two-bottle tests.7. The activity of twenty-nine single taste fibres, selected for their responsiveness to sweetness or acids or both, was recorded after miraculin treatment. Effects were obtained in nine fibres which were similar but more pronounced than those observed in the summated recordings. Before miraculin, these fibres responded better and to a larger variety of sweeteners (81%) than the other fibres (40%). After miraculin, acids elicited on the average 2.3 times more activity than before, while the response to sweeteners was depressed. In twenty fibres no effect of miraculin was observed. These fibres responded to fewer of the sweeteners and were more stimulated by the non-sweet stimuli than the first group.8. The results suggest that miraculin acts on those structures in the taste cell membrane that are involved in perception of the sweet taste, making them sensitive to acids. The new quality of sweetness after miraculin treatment is signalled by taste fibres which normally respond to sweet substances but which, under the influence of miraculin, are responding to acids. It is likely that the quality of a taste stimulus is conveyed by the identity of the taste fibres.

Acids↗
PubMed1983

Serological method for identification of Vibrio parahaemolyticus from marine samples.

Use of agglutination with antiserum against lateral flagella (H-agglutination) for the identification of Vibrio parahaemolyticus was studied. Sucrose-negative bacteria were isolated from seawater, and their characterization was carried out by traditional biological tests and slide agglutination with antiserum specific to lateral flagella of V. parahaemolyticus. Of 135 strains isolated, 78 were identified as V. parahaemolyticus by biological tests and were agglutinated with the above serum. Fifty-five strains did not agglutinate with the serum, and their biological characteristics were different from those of V. parahaemolyticus. Two strains also differed from V. parahaemolyticus in some biological characteristics but agglutinated with the antiserum. All clinically isolated V. parahaemolyticus strains also agglutinated with the above serum. These results suggest that our serological method is useful for the identification of V. parahaemolyticus, especially for samples in which there are many organisms related to V. parahaemolyticus, because many biological tests can be omitted.

Agglutination Tests↗
PubMed1982

Gustatory neural response in the mouse.

Gustatory responses from the mouse chorda tympani nerve were tested with various chemical solutions. Magnitudes of integrated chorda tympani responses to the 4 basic taste stimuli were greater in the order of HCl, sucrose, NaCl and quinine-HCl. Sucrose was the most effective sugar tested, while NaCl was the least effective salt, but divalent chloride salts were prominently effective stimulants. Many of single chorda tympani fibers responded specifically to one or two of the 4 basic taste stimuli. Single fibers sampled were classified into the following 5 types: sweet-type, Na-type, Ca-Mg-type, acid-type and quinine-type.

Animals↗
PubMed1982

Relationships between spontaneous discharge rates and taste responses of the dog thalamic neurons.

Response characteristics to the 4 taste stimuli (NaC1, tartaric acid, sucrose and quinine-HCl) and spontaneous discharge rates of taste neurons in the dog thalamus were examined. Response patterns of 72 thalamic neurons were somewhat complex, involving excitation (on type, on-off type and off type) and inhibition (short-term type and long-term type). A comparison among the responses to the 4 taste stimuli renders low response discharge rates and a high incidence of inhibitory responses to quinine-HCl. Measuring of the breadth of responsiveness showed that the thalamic taste neurons have varying sensitivities to the 4 taste stimuli and neurons responding best to quinine-HCl were more broadly tuned than those to each of the other 3 stimuli. These neurons also have varying spontaneous discharge rates and showed some relationship between the spontaneous rates and responses to taste stimuli. Neurons which showed inhibitory responses to stimuli have relatively high spontaneous rates. Neurons with higher spontaneous rates tend to be more narrowly tuned to the 4 taste stimuli. These relationships appeared not only as a general tendency of all the thalamic neurons but also as a characteristic of each of the 3 individual neurons which changed the spontaneous rates and breadth of responsiveness during long time recordings of neural discharges.

Action Potentials↗