Search PubMed⌕ Search

Biomedical subjects

H Toh

Publications and source records attributed to H Toh.

At least 73 records · Page 4Linked to original sources
PubMed1993

Molecular cloning and expression of the gene for serine hydroxymethyltransferase from an obligate methylotroph Hyphomicrobium methylovorum GM2.

The gene encoding serine hydroxymethyltransferase (SHMT), one of the key enzymes of the one-carbon-compound assimilation of a methylotroph, Hyphomicrobium methylovorum GM2, and its flanking regions were isolated using a DNA fragment encoding Escherichia coli SHMT as a probe. Nucleotide sequencing of the recombinant plasmids revealed the SHMT gene codes for the 434-amino-acid protein with a calculated molecular mass of 46,068 Da. The amino-acid sequence of the enzyme showed identity to the sequences of the enzymes from E. coli (55%) and rabbit liver (44%). The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced to an SHMT-deficient E. coli mutant ME5427 (glyA-). The transformed E. coli cells expressed SHMT, which was immunologically and enzymologically indistinguishable from the enzyme isolated from H. methylovorum GM2.

Amino Acid Sequence↗
PubMed1993

Organization and nucleotide sequence of the DNA polymerase gene from the archaeon Pyrococcus furiosus.

We cloned the gene encoding the thermostable DNA polymerase from the archaeon Pyrococcus furiosus. The DNA fragment of 2785 base pair (bp) containing the structural gene for DNA polymerase was sequenced. DNA polymerase (Pfu polymerase), as deduced from the DNA sequence, consisted of 775 amino acids, had a molecular weight of 90, 109, and was structurally homologous to the alpha-like DNA polymerases (family B) represented by human DNA polymerase alpha and Escherichia coli DNA polymerase II. An unrooted phylogenetic tree of the alpha-like DNA polymerases based on the amino acid sequence alignment was constructed. Pfu polymerase, with two other archaeon polymerases, constitutes a group with some animal viruses. The transcription initiation sites of the pol gene were identified by analysis of in vivo transcripts of both from P. furiosus and E. coli, and the promoters were assigned upstream of the pol coding region. A typical promoter sequence for the archaeon was found at a reasonable distance from the transcription initiation site in P. furiosus.

Amino Acid Sequence↗
PubMed1993

Incidence and histology of human accessory parotid glands.

The parotid glands of 228 Japanese human cadavers were examined to determine the incidence and histological features of accessory parotid glands. The incidence was found to be 56% with no differences between right and left sides or between sexes. Thirty parotid glands and their associated accessory glands were examined histologically: eight of these accessory glands were found to be mixed secretory glands (i.e., containing both serous and mucous acini). Thus, the pattern of differentiation of a significant fraction of accessory glands differs from that of the main parotid gland: it appears that mixed acini, present in the early stages of development, persist into later life, and their presence may be related to tumors developing at these sites.

Adult↗
PubMed1993

Fine structure and subepithelial capillaries of the main excretory duct epithelium of the submandibular gland of the Japanese monkey, Macaca fuscata.

The fine structure and subepithelial capillaries of the main excretory duct epithelium (MEDE) of the submandibular gland in the Japanese monkey, Macaca fuscata were investigated by light, scanning, and transmission electron microscopy. Capillaries found beneath the MEDE were all fenestrated ones. Some of them had elevated endothelium known as pored domes. The capillary density (number of capillaries per 200 microns length of MEDE) was 6.05 +/- 1.36, and the number of fenestrae per 10 microns length of available endothelium was 11.62 +/- 3.82. The MEDE was pseudostratified, and consisted of four cell types: Type I and II, which were columnar cells without basal infoldings, basal and goblet cells. The most characteristic feature was the presence of well-developed lateral interdigitations between Type I and II cells.

Animals↗
PubMed1993

Characterization of neutrophil activation by repeated injection of endotoxin in rabbits. Role of neutrophils in the generalized Shwartzman reaction.

The relationship between activated neutrophils and end-organ injury in endotoxemia was studied. The function of peripheral blood neutrophils (PMNs) in rabbits with the generalized Shwartzman reaction (GSR) was compared to that of PMNs rabbits receiving a single injection of endotoxin. The following results were obtained: (1) PMNs from rabbits with the GSR demonstrated enhanced adherence to endothelial cells and increased mitochondrial ATP production; (2) the GSR did not enhance chemotaxis and oxygen radical production of PMNs; (3) a single injection of endotoxin did not cause necrosis of visceral organs; (4) in vitro detachment of endothelial cells by PMNs was increased in rabbits with the GSR; (5) in vivo administration of monoclonal antibody (mAb) against CD11b/CD18 (Mac-1) suppressed the increase in PMN adherence; and (6) hemorrhagic necrosis did not occur when mAb to Mac-1 was injected. Thus, enhanced adherence of PMNs to endothelial cells appears to play a key role in endotoxin-induced end-organ injuries in this animal model.

Animals↗
PubMed1993

Zymomonas mobilis--science and industrial application.

Zymomonas mobilis is undoubtedly one of the most unique bacterium within the microbial world. Known since 1912 under the names Termobacterium mobilis, Pseudomonas linderi, and Zymomonas mobilis, reviews on its uniqueness have been published in 1977 and 1988. The bacterium Zymomonas mobilis not only exhibits an extraordinarily uniqueness in its biochemistry, but also in its growth behavior, energy production, and response to culture conditions, as well as cultivation techniques used. This uniqueness caused great interest in the scientific, biotechnological, and industrial worlds. Its ability to couple and uncouple energy production in favor of product formation, to respond to physical and chemical environment manipulation, as well as its restricted product formation, makes it an ideal microorganism for microbial process development. This review explores the advances made since 1987, together with new developments in the pure scientific and applied commercial areas.

Carbohydrate Metabolism↗
PubMed1993

Keratin expression in taste bud cells of the circumvallate and foliate papillae of adult mice.

The patterns of keratin expression of taste buds in murine oral mucosa were examined using a panel of antibodies with various specificities for cytokeratins. The patterns for taste buds differed markedly from those of the surrounding epithelium but no regional differences in the staining patterns of the taste buds themselves were detected. The taste buds and the ducts of von Ebner's glands were strongly stained by monoclonal antibodies (mAbs) against cytokeratins (K) 8, 18 and 19, those typically expressed by simple epithelia. Merkel cells, which are also present in the oral epithelium and may correspond to the type III cells in taste buds, stained for K8 and K18 but not K19. None of the mAbs against simple epithelial keratins stained the stratifying epithelium of the trench wall or of the oral mucosa. Antibodies with specificity for keratins that are expressed as differentiation products of the mucosal epithelium did not stain taste buds. The staining pattern of the epithelium of the trench wall indicated that it expressed some keratins typical of stratifying epithelia but lacked the full pattern of differentiation of the adjacent mucosal epithelia. Staining within the taste buds was not homogeneous but no clear differences of keratin staining could be directly related to the subtypes of cells constituting them. The markedly differing patterns of keratin expression between taste buds and the adjacent epithelium raises questions about the type of inductive signals that produce and maintain these patterns.

Animals↗
PubMed1993

Prolonged lung edema formation during the generalized Shwartzman reaction in rabbits--can it be a model for septic lung disease?

Pulmonary edema formation and the role of polymorphonuclear leukocytes (PMN) was evaluated during the generalized Shwartzman reaction (GSR) model in rabbits. Chemiluminescence (CL) and superoxide (O2-) production activity stimulated by FMLP were measured in circulating PMN after a single intravenous injection of endotoxin (E. coli 026:B6, 40 micrograms/kg) (E1). CL peaked at 36 hr after E1 injection and then decreased gradually to a normal range within 7 days. O2- production changed in a similar fashion. On the other hand, the PMN count peaked at 72 hr and remained at a high value until day 7. To induce GSR, a second venous injection of endotoxin (40 micrograms/kg) (E2) was administered 36 hr after the first one (E1). Four times as many PMN were observed in the lung capillaries 4 hr after the second endotoxin injection than after the first endotoxin injection (4 hr). The degree of lung edema formed increased after E2, but did not increase after E1. An alveolar hyaline-like exudate was observed 24 hr after E2. A continuous intravenous injection of superoxide dismutase (SOD) plus catalase or PMN depletion, prevented the development of post-E2 lung edema. If E2 was given 7 days after E1, no lung edema formed at all. These data indicate that oxygen free radicals from activated PMN by endotoxin play an important role in prolonged lung edema formation in the GSR model.

Animals↗
PubMed1992

Structural organization of the gene for prostaglandin D synthase in the rat brain.

A 3-kilobase-pair gene for rat brain prostaglandin D synthase [(5Z,13E)-(15S)-9 alpha,11 alpha-epidoxy-15-hydroxyprosta-5,13- dienoate D-isomerase, EC 5.3.99.2], which belongs to the lipocalin family, was isolated from a rat genomic DNA library by plaque hybridization with the cDNA for the enzyme. The gene contains seven exons, and all the splice donor and acceptor sites conform to the GT/AG rule. Transcription initiates at a guanine residue 39 base pairs upstream of the translation initiation codon, as determined by primer-extension analysis of rat brain mRNA. The 5'-flanking region of the gene lacks typical transcriptional regulatory sequences, such as TATA and CAAT boxes, but contains several sets of inverted repeats, direct repeats, and sequences resembling the transcriptional factor Sp1-binding site. The gene structure of prostaglandin D synthase is remarkably analogous to those of other lipocalins, such as beta-lactoglobulin, alpha 2-urinary globulin, placental protein 14, and alpha 1-microglobulin, in terms of number and sizes of exons and phase of splicing of introns. Furthermore, in a multiple alignment of the deduced amino acid sequences, positions of exon/intron junction of the prostaglandin D synthase gene are highly conserved and located around the positions of those of the genes for other lipocalins despite a weak homology.

Amino Acid Sequence↗
PubMed1992

Pilonidal sinus on the neck.

A recurrent nuchal abscess was treated in a 21-year-old obese young man with a total excision of the lesion. In the histopathological findings, many similarities were found between this lesion and pilonidal sinus. We discuss the pathogenesis of this lesion, as well as our belief that this case was a rare example of pilonidal sinus on the neck.

Adult↗
PubMed1992

Molecular evolution of cyclooxygenase and lipoxygenase.

Four oxygenases of the arachidonic acid cascade (cyclooxygenase, 5-lipoxygenase, 12-lipoxygenase and 15-lipoxygenase) were investigated by the method of computer-assisted sequence comparison. From the calculations, some aspects of evolution and function of these enzymes were revealed. (1) The evolutionary origin of cyclooxygenase was different from that of lipoxygenases. (2) Cyclooxygenase was a distantly related member of a peroxidase family. (3) Enzymes with 12-lipoxygenase activity were created independently twice by gene duplication.

Amino Acid Sequence↗
PubMed1992

Human long-chain acyl-CoA synthetase: structure and chromosomal location.

A complementary DNA clone encoding the entire human long-chain acyl-CoA synthetase was isolated and the total 698-amino acid sequence was deduced. The amino acid sequence of human long-chain acyl-CoA synthetase shows 84.9% identity to that of rat long-chain acyl-CoA synthetase. The nucleotide sequences of the protein coding regions between human and rat long-chain acyl-CoA synthetase mRNAs are highly conserved (85.6%), whereas those of the 3' untranslated regions are less conserved (72%). The location of the human long-chain acyl-CoA synthetase gene was identified on chromosome 4 by spot hybridization of flow-sorted chromosomes. Computer-assisted homology search revealed a significant similarity of the enzyme with the enzymes of the luciferase family. Based on this similarity, the structure of human long-chain acyl-CoA synthetase can be divided into five domains: the N-terminus, two domains similar to those in enzymes of the luciferase family, a long gap region between the similar domains and the C-terminus.

Amino Acid Sequence↗
PubMed1992

Molecular evolution of phosphoenolpyruvate carboxylase for C4 photosynthesis in maize: comparison of its cDNA sequence with a newly isolated cDNA encoding an isozyme involved in the anaplerotic function.

Molecular events associated with the evolution of an enzyme for C4 photosynthesis were investigated. In maize, at least three isozymes of phosphoenolpyruvate carboxylase [EC 4.1.1.31] are known: the C4-form, the C2-form and the root-form, being named according to their physiological roles and pattern of tissue distribution [Ting, I.P. & Osmond, C.B. (1973) Plant Physiol. 51, 448-453]. A cDNA clone which presumably encodes the C3-form isozyme was newly isolated and analyzed. Comparison of the sequences of the C3-form and C4-form isozymes revealed that (i) the homologies in the nucleotide and deduced amino acid sequences were 71 and 77%, respectively, and (ii) the gene for the C4-form isozyme evolved under strong G/C pressure. The genes for these isozymes were found to be located apart on different chromosomes. A phylogenetic tree was constructed using 8 amino acid sequences of phosphoenolpyruvate carboxylases from various sources. The topology of the tree indicated that, at least in monocots such as maize and sorghum, the genes for the C4-form and C3-form isozymes diverged from their common ancestral gene earlier than the monocot-dicot divergence (about 2 x 10(8) yr ago), though the divergence of maize (C4 plant) from wheat (C3 plant) is supposed to have occurred much later (6 x 10(7) yr ago).

Amino Acid Sequence↗
PubMed1992

Scanning electron microscopic study on the lingual papillae in the Manchurian chipmunk, Tamias sibiricus asiaticus.

The superfacial structures of the tongues in the Manchurian Chipmunk, Tamias sibiricus asiaticus, were observed by scanning electron microscope. The tongues were long, tapering, narrow and thick with a long apical free portion and a small lingual prominence in the posterior half. In this animal, three circumvallate papillae were present in an inverted triangle, a minority of conical papillae on the pharyngeal part and parallel large conical papillae on the lateral border. The fungiform papillae were scanty on the dorsal surface. These characters suggested this animal was more primitive than the others in rodents.

Animals↗
PubMed1992

Anatomical study of the accessory mental foramen and the distribution of its nerve.

We examined the range of the accessory mental foramen [AMF] and its accessory mental nerve in three Japanese cadavers. The diameters of the AMF were relatively small: 0.74 mm, 0.80 mm and 0.89 mm. The distances between the mental foramen and AMF were: 0.67 mm, 2.1 mm and 5.74 mm. The distribution of the accessory mental nerve was different in the three cases. These nerves communicated with the branches of the facial and buccal nerves.

Aged↗
PubMed1991

[Stress management of overseas Japanese in Kuwait].

Forty percent of the Japanese businessmen in overseas positions are working in developing countries. However, few reports on the mental health care for them have been published. The Japan Overseas Medical Fund and The Kuwait Japanese Association has promoted the Kuwait Japanese Clinic. I had an opportunity to work at this clinic and to study the environmental health of Japanese businessmen in Kuwait. I found that in Kuwait, Japanese businessmen had to adapt to climatic, religious, cultural, and historical differences. Therefore, I investigated the incidence of stress related diseases which are caused by these environmental differences. Stress diseases occurred in 15.7 percent of total cases frequently, and some of them were very severe. After my stay in Kuwait, I believe that the setting up of medical information networks between various countries to alleviate medical anxiety and a system whereby instructions in the differences of medical systems in various countries would be very beneficial.

Environmental Health↗