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Biomedical subjects

Yoshio Fujii

Publications and source records attributed to Yoshio Fujii.

8 recordsLinked to original sources

Intra-individual variation in lumbar bone mineral density as a measure of spondylotic deformity in the elderly.

In an attempt at quantitative assessment of spondylotic deformity, the intra-individual variation in L(1)-L(4) bone mineral density (BMD) was calculated, as the standard deviation (SD) and coefficient of variation (CV), obtained by dividing the SD by mean L(1)-L(4) BMD, in 463 subjects. The subjects ranged in age from their second to tenth decades. Dual-energy X-ray absorptiometry (DXA), using the Lunar DPX-L, was employed to assess the BMD. The SD of lumbar (L)BMD increased with advancing age in males, but not in females, whereas the CV of LBMD increased with age in both males and females, along with the radiographically assessed degree of severity of spondylosis deformans. Both the intra-individual SD and CV of L(1)-L(4) BMD showed a highly significant correlation with the radiological degree of severity of spondylosis deformans, and SD, but not CV, showed a strong dependence on the mean L(1)-L(4) BMD on a multiple regression test. Multiple regression test revealed no significant correlation between on body height, weight, fracture, and intra-individual variation in L(1)-L(4) projected area, reflecting compression fracture, one hand and SD or CV of L(1)-L(4) BMD on the other. Intra-individual variation in lumbar bone mineral density, expressed as a coefficient of variation, is suggested as an index of spondylotic deformity.

Adult↗

An iron-regulated gene required for utilization of aerobactin as an exogenous siderophore in Vibrio parahaemolyticus.

A previous investigation using the Fur titration assay system showed that Vibrio parahaemolyticus possesses a gene encoding a protein homologous to IutA, the outer-membrane receptor for ferric aerobactin in Escherichia coli. In this study, a 5.6 kb DNA region from the V. parahaemolyticus WP1 genome was cloned and two entire genes, iutA and alcD homologues, were identified which are absent from Vibrio cholerae genomic sequences. The V. parahaemolyticus IutA and AlcD proteins share 43 % identity with the Escherichia coli IutA protein and 24 % identity with the Bordetella bronchiseptica AlcD protein of unknown function, respectively. Primer extension analysis revealed that the iutA gene is transcribed in response to low-iron availability from a putative promoter overlapped with a sequence resembling a consensus E. coli Fur-binding sequence. In agreement with the above finding, V. parahaemolyticus effectively utilized exogenously supplied aerobactin for growth under iron-limiting conditions. Moreover, insertional inactivation of iutA impaired growth in the presence of aerobactin and incapacitated the outer-membrane fraction from iron-deficient cells for binding (55)Fe-labelled aerobactin. These results indicate that the V. parahaemolyticus iutA homologue encodes an outer-membrane protein which functions as the receptor for ferric aerobactin. Southern blot analysis revealed that the iutA homologues are widely distributed in clinical and environmental isolates of V. parahaemolyticus. However, additional genes required for ferric aerobactin transport across the inner membrane remain to be clarified.

Amino Acid Sequence↗

Studies of the mechanism of action of the aerolysin-like hemolysin of Aeromonas sobria in stimulating T84 cells to produce cyclic AMP.

We previously reported that the aerolysin-like hemolysin of Aeromonas sobria stimulates T84 cells to produce cyclic AMP, which then emerges in the culture medium. In order to clarify the mechanism of action of the hemolysin, we examined the involvement of adenosine nucleotide. The results show that the hemolysin stimulates T84 cells to release ATP, which is then converted to adenosine by ectonucleotidase. The adenosine generated might stimulate the P1 adenosine receptors of T84 cells to produce cyclic AMP.

Adenosine↗

The effect of active absorbable algal calcium (AAA Ca) with collagen and other matrix components on back and joint pain and skin impedance.

The effect of active absorbable algal calcium (AAA Ca) with collagen and other matrix components on aging-associated skin changes and backache and joint pain was tested in a case-controlled study of 40 test subjects and 40 age-matched control subjects (mean age, 65 years) complaining of backache and knee joint pain due to osteoarthritis, spondylosis deformans, and/or osteoporosis. Supplementation with 900 mg calcium (given as AAA Ca) and 3.5 g collagen and other matrix components, including glucosamine, daily for 4 months resulted in a marked alleviation of subjective pain, assessed by the face scale. A fall of skin impedance in response to exercise loads, such as standing up, walking, squatting, and climbing up and down stairs, reported as an objective manifestion of pain, was also alleviated. The basal skin impedance, which increases with age, was significantly reduced in response to the Ca-collagen-matrix supplementation, suggesting a change of skin properties similar to rejuvenation, along with subjective smoothening and moistening of the skin. Urinary excretion of N-terminal crosslinking telopeptide of type I collagen (NTx) was decreased in the Ca-collagen-matrix supplementation group, but not in the control group. In addition to calcium suppression of parathyroid hormone, preventing bone resorption, collagen, acting on the intestinal lymphatic system, may protect collagen from degradation through the inhibition of cytokine-induced release of metalloproteinases, including collagenase.

Absorption↗

Modulation of Brucella-induced macropinocytosis by lipid rafts mediates intracellular replication.

Intracellular replication of Brucella requires the VirB complex, which is highly similar to conjugative DNA transfer systems. In this study, we show that Brucella internalizes into macrophages by swimming on the cell surface with generalized membrane ruffling for several minutes, after which the bacteria are enclosed by macropinosomes. Lipid raft-associated molecules such as glycosylphosphatidylinositol (GPI)-anchored proteins, GM1 gangliosides and cholesterol were selectively incorporated into macropinosomes containing Brucella. In contrast, lysosomal glycoprotein LAMP-1 and host cell transmembrane protein CD44 were excluded from the macropinosomes. Removing GPI-anchored proteins from the macrophage surface and cholesterol sequestration markedly inhibited the VirB-dependent macropinocytosis and intracellular replication. Our results suggest that the entry route of Brucella into the macrophage determines the intracellular fate of the bacteria that is modulated by lipid raft microdomains.

Animals↗

Physicochemical and biological properties of an extracellular serine protease of Aeromonas sobria.

Previously, we cloned a protease gene of Aeromonas sobria, determined its nucleotide sequence and established a method of purifying its product. In this study, we examined the properties of the purified protease. The protease was temperature-labile and had an optimal pH of 7.5. Metallo-protease inhibitors and a cysteine protease inhibitor did not block the proteolytic activity of the enzyme. The treatment with reagents to modify sulfhydryl group did not reduce the activity. But, serine protease inhibitors did, showing that it was a serine protease. Subsequently, we examined the ability of the protease to enhance vascular permeability in dorsal skin. The protease showed activity and the reaction was inhibited by a simultaneously injected antihistaminic agent. Histopathological examination showed that mast cells appeared around the site where the protease was injected. These findings show that the vascular permeability-enhancing effect of the protease is due to histamine released at the site. Furthermore, we found that a soybean trypsin inhibitor (Kunitz) did not block the proteolytic action of the protease in vitro, but inhibited its vascular permeability-enhancing activity in skin. This suggests that a trypsin-like protease from skin mediates the activity of the protease to enhance its vascular permeability.

Aeromonas↗

The protein encoded at the 3' end of the serine protease gene of Aeromonas sobria functions as a chaperone in the production of the protease.

For the successful production of Aeromonas sobria serine protease (ASP), open reading frame 2 (ORF2) protein, encoded at the 3' end of the protease operon, is required. In this study, we examined the action of ORF2 protein. The results showed that the protein associated with ASP in the periplasm and helped ASP to form an active structure.

Aeromonas↗