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H Fukami

Publications and source records attributed to H Fukami.

At least 19 recordsLinked to original sources
PubMed2001

Quantitative analysis of synaptic contacts made between functionally identified oralis neurons and trigeminal motoneurons in cats.

A previous study revealed that rostrodorsomedial oralis (Vo.r) neurons synapsing on trigeminal motoneurons use GABA and/or glycine as neurotransmitters. To determine the number and spatial distribution of contacts, injections of biotinamide and horseradish peroxidase were made into a Vo.r neuron and an alpha-motoneuron in the jaw-closing (JC) and jaw-opening (JO) motor nucleus, respectively, in 39 cats. All Vo.r neurons responded to low-threshold mechanical stimulation of the oral tissues. Single Vo.r neurons terminating in the JC nucleus (Vo.r-dl neurons; n = 5) issued, on average, 10 times more boutons than Vo.r neurons terminating in the JO nucleus (Vo.r-vm neurons; n = 5; 4437 vs 445). The Vo.r-dl neuron-JC alpha-motoneuron pairs (n = 4) made contacts on either the soma-dendritic compartment or dendrites, and the Vo.r-vm neuron-JO motoneuron pairs (n = 2) made contacts on dendrites, with a range of two to seven contacts. In five of the six pairs, individual or groups of two to three terminals contacted different dendritic branches of a postsynaptic cell. The Vo.r-dl neurons innervated a greater number of counter-stained motoneuronal somata than did the Vo.r-vm neurons (216 vs 26). Total number of contacts per Vo.r neuron was higher for the Vo.r-dl than Vo.r-vm neurons (786 vs 72). The present study demonstrates that axonal branches of Vo.r neurons are divided into two types with different innervation domains on the postsynaptic neuron and that they are highly divergent. The overall effect exerted by these neurons is predicted to be much greater within the JC than JO motoneuron pool.

Action Potentials↗
PubMed2001

Hexosaminidase-altered aberrant crypts, carrying decreased hexosaminidase alpha and beta subunit mRNAs, in colon of 1,2-dimethylhydrazine-treated rats.

Aberrant crypt foci (ACF), consisting of morphologically irregular crypts, are thought to be precancerous lesions for colon cancers. For their molecular analysis, it is necessary to avoid contamination with adjacent normal crypts and stromal cells. Decreased hexosaminidase activity in ACF, which has been histochemically demonstrated, was used in the present study to classify isolated crypts in combination with morphological changes. The length, rim diameter, and width (average SD, microm) of hexosaminidase-positive (Hex + ) crypts were 238.6 +/- 40.4, 89.5 +/- 22.9, and 57.6 +/- 14.0, respectively. For hexosaminidase-negative (Hex - ) crypts, the values were 314.4 +/- 77.8, 140.3 +/- 45.7, and 97.3 +/- 34.7, the width being 1.69 times greater (P < 0.0001). Crypts wider than 115 microm (approximately 2 times the average size of Hex + crypts) were all from ACF, judging from hexosaminidase staining. To analyze transcription levels of Hex alpha and beta subunits (Hexa and Hexb, respectively), real-time relative quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed using the LightCycler system. In aberrant crypts, both Hexa and Hexb were significantly down-regulated to 0.266 (P < 0.002) and 0.131 (P < 0.001) units, respectively, compared with those in morphologically normal crypts, with beta-actin as the internal standard. This decrease could be a molecular marker for precancerous enzyme-altered ACF.

1,2-Dimethylhydrazine↗
PubMed2001

Treatment of hypersaline-containing wastewater with salt-tolerant microorganisms.

Two salt-tolerant bacteria were isolated from soil samples to treat a high-salt-content wastewater from a pickled plum production plant. The strains, which were identified as Staphylococcus sp. and Bacillus cereus, grew well in a medium containing 0 to 15% NaCl. When wastewater in a flask was treated with the strains for 72 h, the COD removal was about 70%, and this was increased to about 90% when they were used in a pilot plant (working volume 1 m3) in a batch culture carried out for 7 d. The Staphylococcus sp. and Bacillus cereus strains occupied almost all of the pilot plant, in which they were present in a ratio of 3:1 (at 23-27 degrees C).

Journal Article↗
PubMed2001

The relationship between a leaf-rolling moth (Dactylioglypha tonica) and fungi covering the cocoon.

To discover the relationship between a leaf-rolling moth and the fungi densely covering its cocoons, the rolled nest leaves were collected in two districts in Japan and antibacterial properties of the fungi were examined. Cocoons and fungi isolated from the nest were classified into 5 categories by the growth stages of the insects, and 7 categories based on taxonomic properties and pigment productivity, respectively. The dominant genus was Penicillium in each location. However, the composition of the fungal categories was different and seemed to depend on their circumstances. From all cocoons with larvae, the strains that belonged to the same fungal category and produced the same antibiotic (deoxyherqueinone) were isolated. From these results, the species-specific relationship between the insect and fungi or fungal products was considered to be not extremely tight, and it was suggested the period of the larval spinning of the cocoon is a key stage of this unique relationship.

Animals↗
PubMed2001

An efficient screening approach for anti-Microcystis compounds based on knowledge of aquatic microbial ecosystem.

To improve the efficiency of screening for anti-Microcystis compounds, we planned to use algae-lysing bacteria that kill the organisms of water blooms. A two step-screening process was carried out, i.e., the screening of algae-lysing bacteria and the selection of anti-Microcystis producers from the bacteria. Sources for the isolation of the bacteria were a co-cultivated fluid of a water sample with axenic Microcystis viridis, a water sample collected in a water bloom season, and a water bloom sample. The water bloom sample was the best source for the isolation of the algae-lysing bacteria and such bacteria were shown to exhibit potent activity. Seventeen strains out of 20 isolated algae-lysing bacteria produced anti-Microcystis activities, and one of the principles was the previously reported argimicin A. These results indicate that algae-lysing bacteria in water blooms may be good sources for potent and selective anticyanobacterial compounds.

Cell Extracts↗
PubMed2000

Quantitative ultrastructure of physiologically identified premotoneuron terminals in the trigeminal motor nucleus in the cat.

Little is known about the ultrastructure of synaptic boutons contacting trigeminal motoneurons. To address this issue, physiologically identified premotor neurons (n = 5) in the rostrodorsomedial part of the oral nucleus (Vo.r) were labeled by intracellular injections of horseradish peroxidase (HRP) in cats. The ultrastructure of 182 serially sectioned axon terminals from the five neurons was both qualitatively and quantitatively analyzed. In addition, the effects of the glycine antagonist strychnine, GABA(A) antagonist bicuculline, NMDA antagonist 2-amino-5-phosphonovalerate (APV), and non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on Vo.r-induced postsynaptic potentials in trigeminal motoneurons (n = 11) were examined to evaluate potential signaling substances of the premotor neurons. Labeled boutons made synaptic contacts with either jaw-closing or -opening motoneurons. All the boutons contained pleomorphic vesicles, and most formed a single symmetric synapse either on the somata or on primary dendrites. Morphometric analyses indicated that bouton volume, bouton surface area, apposed surface area, total active zone area, and mitochondrial volume were not different between boutons on jaw-closing and -opening motoneurons. Vesicle number and density, however, were higher for boutons on jaw-closing motoneurons. The five morphological parameters were positively correlated with bouton volume. Vesicle density was the exception, which tending to be negatively correlated. Intravenous infusion of strychnine or bicuculline suppressed Vo.r-induced inhibitory postsynaptic potentials (IPSPs) in jaw-closing motoneurons. Abolition of Vo. r-induced excitatory postsynaptic potentials in jaw-opening motoneurons with APV and CNQX unmasked IPSPs. The present results suggest that premotor neurons in the Vo.r are inhibitory and that positive correlations between the ultrastructural parameters associated with synaptic release and bouton size are applicable to the interneurons, as they are in primary afferents.

2-Amino-5-phosphonovalerate↗
PubMed2000

Mouse strain susceptibility to diethylnitrosamine induced hepatocarcinogenesis is cell autonomous whereas sex-susceptibility Is due to the micro-environment: analysis with C3H <--> BALB / c sexually chimeric mice.

In man, liver cancer is on the increase, especially in males. Sex differences also exist in rodent models. To elucidate the mechanisms, chimeric mice were produced by amalgamation of early embryos from high and low hepatocarcinogen-susceptible strains, C3H and BALB / c. Tumor formation was initiated with 10 mg / kg of diethylnitrosamine at the ages of 7 and 14 days and mice were sacrificed at 30 and 45 weeks. The chimeras were classified into XY <--> XY, XY <--> XX, XX <--> XY, and XX <--> XX in terms of sex chromosomes by means of polymerase chain reaction-simple sequence length polymorphism analysis (SSLP) using Y chromosome-specific Sry primers in combination with the D3Mit21 marker. Liver lesions were analyzed histopathologically, by immunostaining using a C3H strain-specific antibody and by DNA in situ hybridization with the Y chromosome-specific digoxigenin-labeled Y353 / B probe. Sex and strain genotyping by SSLP analysis matched histological observations, confirming the reliability of our system. The strain differences in liver tumor numbers of each strain type in XY <--> XY and XX <--> XX subtypes of C3H <--> BALB / c chimeras were retained well (P < 0. 0001 and P < 0.001, respectively), indicating a minimum influence of the C3H or BALB / c surrounding milieu on development of individual lesions. On the other hand, significant promotion of XX cell tumors was evident in phenotypically male sexually chimeric XY <--> XX and XX <--> XY chimeras for both C3H (P < 0.02) and BALB / c (P < 0.01) lesions compared to the XX <--> XX case. The results suggest the presence of hormonal or micro-environmental factors specific for males, which are not caused cell-autonomously. Basic strain differences, however, are determined by intrinsic genetic factors rather than the strain-dependent micro-environment.

Animals↗
PubMed2000

More frequent beta-catenin gene mutations in adenomas than in aberrant crypt foci or adenocarcinomas in the large intestines of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-treated rats.

Alteration of adenomatous polyposis coli (APC) is known to be an early event in neoplasia, causing activation of the beta-catenin / Tcf pathway. Although it is thought that alterations in APC and beta- catenin may complement one another, the contribution of beta-catenin mutations to colorectal carcinogenesis remains unclear. We therefore performed PCR-single strand conformation polymorphism analysis and direct sequencing of exon 3 of beta-catenin gene in adenomas, adenocarcinomas, and aberrant crypt foci (ACF), considered to be putative precursor lesions of colorectal neoplasias, in 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) treated F344 rats. beta-Catenin mutations were identified in all of 7 adenomas (100%) and 6 of 12 (50%) adenocarcinomas. All of the mutations were found in codons 32 through 34, the serine encoded by codon 33 being an important phosphorylation site by glycogen synthase kinase-3beta. Regarding ACF, 14 of 46 (30.4%) were found to be mutated, eleven (78%) in codon 34, and the others in codon 45 (frequently altered in human colon cancer), and codons 47 and 56 (which have not been previously reported). The frequency of beta-catenin mutations in adenomas was significantly higher than in ACF (P < 0.001) and adenocarcinomas (P < 0.05). Thus, beta-catenin mutations may have more importance in the genesis of adenomas than ACF or adenocarcinomas in rat colon carcinogens by PhIP.

Adenocarcinoma↗
PubMed2000

Substituted 3-phenylsulfonylquinazoline-2,4-dione derivatives as novel nonpeptide inhibitors of human heart chymase.

A series of 3-phenylsulfonylquinazoline-2,4-dione derivatives have been synthesized and evaluated for their ability to inhibit human heart chymase. The structure-activity relationship studies on these compounds gave the following results. The phenyl moiety of quinazoline participates in a hydrophobic interaction where an optimum size is required. In this moiety, 7-chloroquinazoline is the best moiety for inhibiting chymase, chymotrypsin and cathepsin G. A 3-phenylsulfonyl moiety substituted with hydrophobic electron-withdrawing groups at the 4-position potentiated the activity. Anthranil moiety also enhanced the activity. Pyridylmethyl and N-pyridylacetamide at the 1-position gave an IC50 in the order of 10(-8)M. Molecular modeling studies on the interaction of 7-chloro-3-(4-chlorophenylsulfonyl) quinazoline-2,4(1H, 3H)-dione (4) with the active site of human heart chymase suggested that the phenyl moiety of quinazoline interacts with the hydrophobic P1 pocket, the 3-phenylsulfonyl moiety resides in the S1'-S2' subsites, the moiety at the 1-position locates in the S2-S3 subsites and the 4-carbonyl and 3-sulfonyl group interact with the oxyanion hole and the His57 side-chain of chymase, respectively.

Chymases↗
PubMed1999

Physiologic and morphologic properties of motoneurons and spindle afferents innervating the temporal muscle in the cat.

Little is known about physiology and morphology of motoneurons and spindle afferents innervating the temporalis and on synaptic connections made between the two. The present study was aimed at investigating the above issues at the light microscopic level by using the intracellular recording and horseradish peroxidase or biotinamide labeling techniques and by the use of succinylcholine (SCh) for the classification of spindle afferents in the cat. Temporalis motoneurons had dendritic trees that ranged from a spherical form to an egg-shaped form. The shape deformation was more prominent for the dendritic trees made by motoneurons located closer to the nuclear border. No axon collaterals of the motoneurons were detected. On the basis of the values for the dynamic index after SCh infusion, temporalis spindle afferents were classified into two populations: presumptive groups Ia and II. The spindle afferents terminated mainly in the supratrigeminal nucleus (Vsup), region h, and the dorsolateral subdivision (Vmo.dl) of the trigeminal motor nucleus (Vmo). The proportion of group Ia afferent terminals was lower in the Vsup than that of group II afferents. In the Vmo.dl, the proportion of group Ia afferent terminals was nearly even throughout the nucleus, but that of group II afferent terminals increased in the more outlying regions. The proportion of terminal distribution in the central region of Vmo.dl was higher for group Ia than group II. The frequency of contacts (presumptive synapses) made by a single spindle afferent on a motoneuron was higher for group Ia than group II. The present study provided evidence that the central organization of spindle afferent neurons is different between groups Ia and II.

Animals↗
PubMed1999

Reproductive and genetic evidence for a reticulate evolutionary history of mass-spawning corals.

Reef-building corals, which reproduce through simultaneous multispecies spawning, are thought to hybridize frequently, and it is hypothesized that they have evolved in repeated rounds of species separation and fusion. We conducted cross-fertilization experiments and molecular analyses with a number of mass-spawning coral species in the genus Acropora. A high rate of interspecific fertilization occurred between some species despite very different morphologies. The hybrid larvae developed normally and contained an allelic sequence transmitted from each parent, suggesting common diploid hybridization. Molecular phylogenetic analyses provided strong evidence for a gene pool shared between the hybridizing species. These reproductive and genetic characteristics are consistent with a species complex formed under the separation/fusion processes predicted for a reticulate evolutionary history.

Animals↗
PubMed1999

Development and distribution of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced aberrant crypt foci in the rat large intestine.

Aberrant crypt foci (ACF) are generally considered to be preneoplastic lesions for colon cancer. To assess their induction by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a colon carcinogen, we performed a sequential study of ACF morphology and localization. F344 male rats were given PhIP, and methylene blue-stained colon epithelium and isolated crypts were analyzed at weeks 12, 25, 50, and 75. Each crypt was classified into 2 groups, "single" with round bottoms and "bifurcating" displaying V-shaped clefts (indicating proliferation). In combination with the number of crypts in an ACF, this classification was a good indicator for the generation of ACF in line with the fission mechanism of growth. Increasing numbers of crypts in ACF through weeks 12 to 75 and decreased percentages of ACF with bifurcating crypts at the late time points indicated that proliferation of crypts occurs predominantly during the early stages. The distribution pattern showed a significant shift (P < 0.000005) from the distal to the proximal part of the large intestine between weeks 25 and 50. Adenocarcinomas were first found to develop at week 50 in the ascending colon and cecum where bifurcating crypts were generally lacking at weeks 12 and 25. These data suggest the existence of (1) proliferating ACF which contains bifurcating crypt(s) and (2) quiescent or senescent ACF which consists of only single crypts.

Animals↗
PubMed1999

Clonality of urogenital organs as determined by analysis of chimeric mice.

Though the first mammalian chimera was reported in 1961, suitable markers for different animal strains which are easily detectable in histological sections of all or most organs have not existed. Chimeric mice were produced having an excellent histological marker, the C3H antigen, which is strain-specific and fulfills all the criteria for an ideal strain-specific histological marker. Using male and female C3H-Balb/c chimeric mice we examined epithelial cells of urogenital organs and their morphological or functional units, such as the glomerulus, to determine whether individual organs and their morphological subunits were monoclonal or polyclonal in origin. We found that the epithelial parenchyma of most male and female urogenital organs (the prostate, seminal vesicle, epididymis, ovaries, vagina, kidney, ureter and bladder) and their morphological subdivisions were derived from cells of both input strains, indicating a polyclonal origin for each organ and/or organ component. A notable exception was the uterus in which all individual uterine glands examined (n = 403) were found to be either entirely Balb/c or entirely C3H, indicating a monoclonal origin. The clonality of urogenital structures is discussed in terms of the morphogenesis of the urogenital system.

Animals↗
PubMed1998

Clonal analysis of urothelial carcinomas in C3H/HeN<-->BALB/c chimeric mice treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

The histological background for multifocal and metachronous development of urothelial carcinomas remains equivocal, although accumulated genetic evidence suggests monoclonal origin of multiple urothelial carcinomas. Clonal development of various preneoplastic and neoplastic urothelial lesions of C3H<-->BALB/c chimeric mice induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was immunohistochemically investigated using a C3H strain-specific antibody. All tumor masses induced in the mice treated with 0.05% BBN for 20 weeks were composed of neoplastic cells of a single parental type, which is indicative of monoclonal lesions. Three of 10 animals harbored two or more separate carcinomas of different clonal type, which is indicative of multicentric development applicable in this model. Using DNAs derived from urothelial carcinomas and tumor-adjacent urothelium of chimeric mice, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing were performed for p53 gene exons 5-7. p53 mutations were identified in four of 11 (36%) dysplasias and non-invasive carcinomas (carcinoma in situ and pTa tumor) and 13 of 22 (59%) invasive carcinomas. Only in a single case were identical p53 mutations found in separate urinary bladder carcinomas. In contrast to the random distribution of urothelial proliferating units in chimeric mice without chemical supplement, invasive carcinomas in BBN-treated mice were accompanied by widely-distributed preneoplastic and neoplastic lesions of the same clonality, which occasionally had frequent foci of microinvasion. This is indicative of lateral clonal expansion of the clones, which precedes the bulk of invasive carcinomas. Thus, two aspects of 'field change' of the urothelium became evident in this model: either independent transformation events or lateral clonal expansion might, respectively, result in multicentric and monoclonal carcinoma development in the urinary tract.

Animals↗
PubMed1998

Induction of glandular stomach cancers in Helicobacter pylori-sensitive Mongolian gerbils treated with N-methyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine in drinking water.

An animal model of stomach carcinogenesis was established using Mongolian gerbils with N-methyl-N-nitrosourea (MNU) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) as the carcinogens. In addition, the sensitivity of these gerbils to Helicobacter pylori (H. pylori) was confirmed. One hundred and sixty specific pathogen-free male MGS/Sea animals, 7 weeks old, were treated with MNU in the drinking water (30 ppm for alternate weeks to give 10 weeks exposure, or 10 ppm or 3 ppm for 20 weeks continuous exposure), or given MNNG in the drinking water at 400 ppm or 200 ppm for 20 weeks, or orally inoculated with ATCC43504 H. pylori (1.7 x 10(8) CFUs/animal). Adenocarcinomas in the glandular stomach were found in 2 out of 12 effective animals (2/ 12) treated with 30 ppm MNU at week 20, although all were dead or moribund by week 30 due to MNU toxicity. At week 50, the incidences of gastric adenocarcinomas in groups treated with 10 ppm MNU, 3 ppm MNU, 400 ppm MNNG, and 200 ppm MNNG were 2/21 (9.5%), 1/23 (4.3%), 7/ 11 (63.6%), and 1/10 (10.0%). The lesions were generally well differentiated, although poorly differentiated adenocarcinoma was also found in a single gerbil in each of the 10 ppm MNU and 400 ppm MNNG groups. In control animals no tumors were found. In the infection study, the animals were killed at week 20, and H. pylori was detected in all cases, causing multiple erosions with marked inflammatory cell infiltration in the lamina propria and submucosa, and frequent formation of lymphoid follicles. Thus, MNU and MNNG in the drinking water induced neoplastic lesions in the glandular stomach epithelium of H. pylori-sensitive gerbils.

Adenocarcinoma↗
PubMed1998

Chymase: its pathophysiological roles and inhibitors.

Chymase is a chymotrypsin-type serine protease mainly localized in mast cells (MCs). Human, primate, and dog chymase generate angiotensin II (Ang II) from Ang I, while mouse and rat chymases degrade Ang II. It is suggested that chymase generating Ang II might be an alternative Ang II-forming enzyme to angiotensin-converting enzyme (ACE) in the renin-angiotensin system in tissues, but not in blood, and cause hypertrophy and remodeling of cardiovascular tissues. Chymase also degrades extracellular matrix, and processes procollagenase, inflammatory cytokines and other bioactive peptides. As a result, chymase plays important roles in inflammatory tissues through its proteolytic activities to cause tissue remodeling, that is, a chymase inhibitor may have the ability to prevent diseases caused by the above inflammatory reactions. The investigation of chymase inhibitors by pharmaceutical companies has yielded peptide and peptide mimetic inhibitors. We also found potent non-peptide low molecular inhibitors. However, the in vivo functions of chymase have not been verified so far by applying a chymase inhibitor to in vivo pathological models. In this article, we overview the pathophysiological roles of chymase and chymase inhibitors proposed to date, and discuss the structure-activity relationships of substituted 3-phenylsulfonyl-1-phenylimidazolidine-2,4-dione derivatives.

Angiotensin I↗