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Biomedical subjects

R Oda

Publications and source records attributed to R Oda.

At least 19 recordsLinked to original sources
PubMed2007

Light-responsive hydrophobic association of azobenzene-modified poly(acrylic acid) with neutral surfactants.

Photoresponsive association between azobenzene-modified poly(acrylic acid)s (AMPs) and the nonionic surfactants tetraethylene glycol monododecyl ether and octadecyl ether (C12E4 and C18E4) has been achieved in dilute aqueous solution. The binding was investigated by (i) spectrophotometry that probes the polarity close to the azobenzene chromophore, (ii) capillary electrophoresis to obtain the amount of C12E4 bound per polymer chain, and (iii) pressure-area curves of Langmuir films to obtain information on the adsorption of AMP at the water-C18E4 interface. Increasing hydrophobicity of AMP (with increasing degree of modification with azobenzene side-groups) tightened the association with C12E4 in the dark. Exposure to UV light rapidly converted the azobenzene to their more polar cis isomer, which in turn weakened the association with surfactant. Almost complete photorelease of bound C12E4 was obtained with the optimal structure of AMP. Adsorption on large interfaces is much less sensitive to light. The possible origin of the photoresponse is analyzed in terms of AMP affinity for surfactant assemblies and azobenzene penetration in the hydrophobic core of micelles. We propose that the photoswing of polarity is amplified by the binding to small micelles because of the small number of anchors involved. A few azobenzene anchors afford tight binding in the dark, but also detach more easily than the whole AMP chain upon photoisomerization.

Journal Article↗
PubMed2001

Lack of association between the hKCa3 gene and Japanese schizophrenia patients.

Several researchers have suggested an association between large numbers of CAG repeats in the hKCa3 gene and schizophrenia. However, these reports remain inconclusive and require further investigation. We tried to replicate these results in 112 Japanese schizophrenia patients and 102 control subjects of highly matched age and sex by applying an allele dichotomization model. No association was found. The overall distributions of allele frequencies were not significantly different between schizophrenic patients and normal control subjects. In addition, we tested the association between the size of the CAG repeats and the scores on three dimensions (positive and negative symptoms, and disorganization), but no significant results were obtained. Our results do not support the involvement of the hKCa3 gene in schizophrenia, at least in the Japanese population.

Adult↗
PubMed2000

[The advantages and disadvantages of Artemisia princeps and A. montana].

In Japan, Moxa is made from Artemisia princeps and A. montana P. which are plants of the composiae family. Evaluations of the superiority or inferiority of these raw materials for Moxa have been confusing. The judgement of superiority or inferiority is roughly based on the strenght of the fragrance and somewhat of down. When I investigated 14 kinds of documents from the Edo period to the Showa period, 10 of the documents gave good evaluations for Artemisia princeps. On the other hand the remaining four gave good evaluations for A. montana P. But there is quite an opposite opinion, because the four deemed good for Artemisia princeps were misunderstood regarding the discrimination of Artemisia princeps and A. montana P. Since correcting them, each material has seven good evaluations, tying the score. Therefore, I researched the contents of the principal ingredient, Cineole, using an important evaluation index and the fragrances were compared measuring both materials, which were collected from different places. The results to examining six kinds of Artemisia princeps, and eight kinds of A. montana P. (14 kinds in total) are as follows: The A. montana P. contents Cineole was more abundant than the other on average. However, it is from three to five times the change by the growing both ground, and superiority or inferiority cannot be decided indiscriminately. When quality is evaluated, it is necessary to clarify the materials orgin. Generally speaking, the fragrance of A. montana P. is stronger than the other.

History, Modern 1601-↗
PubMed1999

Tuning bilayer twist using chiral counterions.

From seashells to DNA, chirality is expressed at every level of biological structures. In self-assembled structures it may emerge cooperatively from chirality at the molecular scale. Amphiphilic molecules, for example, can form a variety of aggregates and mesophases that express the chirality of their constituent molecules at a supramolecular scale of micrometres. Quantitative prediction of the large-scale chirality based on that at the molecular scale remains a largely unsolved problem. Furthermore, experimental control over the expression of chirality at the supramolecular level is difficult to achieve: mixing of different enantiomers usually results in phase separation. Here we present an experimental and theoretical description of a system in which chirality can be varied continuously and controllably ('tuned') in micrometre-scale structures. We observe the formation of twisted ribbons consisting of bilayers of gemini surfactants (two surfactant molecules covalently linked at their charged head groups). We find that the degree of twist and the pitch of the ribbons can be tuned by the introduction of opposite-handed chiral counterions in various proportions. This degree of control might be of practical value; for example, in the use of the helical structures as templates for helical crystallization of macromolecules.

Membranes↗
PubMed1998

Expression of membrane-bound transferrin-like protein p97 on the cell surface of chondrocytes.

A concanavalin-A-binding protein of 76 kDa was purified from the plasma membrane fraction of rabbit chondrocyte cultures. Amino acid sequencing of the N-terminal region and of tryptic peptides of the protein, in addition to sequencing of its cDNA revealed that this protein is highly similar to the tumour-associated antigen p97. Hence, it was concluded that this protein is the rabbit form of p97. Western blotting, Northern blotting and reverse-transcription PCR analyses indicated that rabbit p97 is expressed at high levels in cartilage and chondrocytes, but is barely detectable in the bone, liver, kidney, small intestine, eye, pancreas, heart, testis, skeletal muscle, spleen and fibroblasts. Immunocytochemical and immunohistochemical analyses demonstrated that p97 is expressed in the plasma membrane of chondrocytes. p97 transcript was detected in all zones of the cartilage but the level was relatively low in the hypertrophic zone. These findings suggest that p97 is involved in maintaining the cell surface characteristics of chondrocytes.

Amino Acid Sequence↗
PubMed1998

Changes in the activity budget of cycling female chimpanzees.

This study is a preliminary report on the time allocated to various activities by female wild chimpanzees (Pan troglodytes schweinfurthii) during their sexual cycle. Cycling females with maximal tumescence (estrous females) tended to spend more time moving than cycling females with quiescent sexual skin (anestrous females). Although there was no statistically significant decrease in any specific activity that corresponded to the increase in time spent moving, feeding time did decrease in four of the five females. The frequency of approach by females toward males and the frequency of approach by males toward females significantly increased when females were in estrus. Direct aggression by males occurred more frequently toward estrous females than toward anestrous females. The copulation frequency and the frequency of approach to males was not significantly correlated with the increase in time spent moving. There was a high but not significant correlation between the time spent moving and the frequency of direct aggression by males toward females. Mating effort, feeding competition, male aggression, and other possible reasons that might explain the increase in moving time are discussed.

Aggression↗
PubMed1997

The Effect of Fluctuations on Bilayer and Monolayer Systems: High-Resolution X-ray Scattering Study of a Three-Component Lamellar Phase

We have investigated the effect of symmetry on the fluctuation of a three-component lamellar phase composed of oil (octane), water, and a nonionic surfactant (C12E5). The studied lamellae consist of various oil/water volume ratios for a fixed surfactant concentration. From aligned lamellae, we succeeded in obtaining highly reproducible, high-resolution X-ray spectra with very small full width at half maximum (6 x 10(-4) A-1 ). The deviation of the periodicity expected by the dilution law can be explained from the fluctuations. Measuring this deviation, we observed that for the constant surfactant concentration, lamellae with equal oil/water ratios have higher fluctuation than when oil/water --> 0 or infinity because of the difference of the flexibility of monolayers and bilayers

Journal Article↗
PubMed1997

Effects of concanavalin A on chondrocyte hypertrophy and matrix calcification.

Resting chondrocytes do not usually undergo differentiation to the hypertrophic stage and calcification. However, incubating these cells with concanavalin A resulted in 10-100-fold increases in alkaline phosphatase activity, binding of 1,25(OH)2-vitamin D3, type X collagen synthesis, 45Ca incorporation into insoluble material, and calcium content. On the other hand, other lectins tested (including wheat germ agglutinin, lentil lectin, pea lectin, phytohemagglutinin-L, and phytohemagglutinin-E) marginally affected alkaline phosphatase activity, although they activate lymphocytes. Methylmannoside reversed the effect of concanavalin A on alkaline phosphatase within 48 h. Concanavalin A did not increase alkaline phosphatase activity in articular chondrocyte cultures. In resting chondrocyte cultures, succinyl concanavalin A was as potent as concanavalin A in increasing alkaline phosphatase activity, the incorporation of [35S]sulfate, D-[3H]glucosamine, and [3H]serine into proteoglycans, and the incorporation of [3H]serine into protein, although concanavalin A, but not succinyl concanavalin A, induced a rapid change in the shape of the cells from flat to spherical. These findings suggest that concanavalin A induces a switch from the resting, to the growth-plate stage, and that this action of concanavalin A is not secondary to changes in the cytoskeleton. Chondrocytes exposed to concanavalin A may be useful as a novel model of endochondral bone formation.

Alkaline Phosphatase↗
PubMed1996

[Simejigahara, a place noted for moxa].

Shimejigahara is a place-name often used in old Waka (Japanese poems). It was reputed in the past to be a site rich in the plants moxa and mugwort. A study of this placed carried out. Shimejigahara, as mentioned in the literature of the Heian to Kamakura eras, seems to have been located at the site of the current Tochigi City. During the Edo era, however, Senjogahara in Nikko came to be referred to as Shimejigahara. In addition, some other places in what is now called Utsunomiya City, on Ibuki Mountain in Shiga Prefecture, and in Chiba City were referred to as Shimejigahara during the Edo era. When the types of wild mugwort seen in these various sites called "Shimejigahara" were searched for, Artemisia princeps P. was found in the cities of Tochigi, Utsunomiya and Chiba, while A. montana P. was seen in Senjogahara and on Ibuki Mountain. Papers published during the Edo era suggest that moxa, gathered in the Shimejigahara, was on the market during that period. It is, however, doubtful that the moxa produced from Shimejigahara was really commercialized, like the well-known "Ibuki moxa."

History, Modern 1601-↗
PubMed1994

Lysosomal enzyme replacement using alpha 2-macroglobulin as a transport vehicle.

Improvement of the delivery of exogenous enzymes is essential to achieve effective enzyme replacement therapy in lysosomal storage diseases. To test whether alpha 2-macroglobulin, an endogenous plasma protein, could serve as a transport vehicle of therapeutic agents to cells, alpha 2-macroglobulin and acid alpha-glucosidase or alpha-galactosidase A were coupled using two heterobifunctional cross-linking reagents. The alpha-glucosidase-alpha 2-macroglobulin conjugate was internalized and transported into lysosomes of acid alpha-glucosidase-deficient fibroblasts. The enzyme activity was stable after being taken up by the cells. Uptake of the conjugate resulted in the degradation of glycogen accumulated in lysosomes. The alpha-galactosidase A-alpha 2-macroglobulin conjugate was also internalized into the lysosomes of alpha-galactosidase A-deficient fibroblasts. Internalized alpha-galactosidase A-conjugate degraded globotriaosylceramide accumulated in lysosomes. The endocytosis of both conjugate was inhibited by alpha 2-macroglobulin-trypsin complex, indicating that the conjugates were endocytosed by an alpha 2-macroglobulin receptor system. These results showed the usefulness of alpha 2-macroglobulin as a transport vehicle of lysosomal enzymes for effective enzyme replacement.

Animals↗
PubMed1989

Molecular techniques for the detection of Chlamydia trachomatis.

A DNA probe assay (PACE; Gen-Probe, San Diego, Calif.) was compared with a culture reference method for the detection of Chlamydia trachomatis. Using stock isolates of each of the 15 serovars (A to K, Ba, L1, L2, and L3) of C. trachomatis, the lower limit of sensitivity for the DNA probe ranged between 1,086 inclusion-forming units (IFU) for serovar E (Bour) to 2,930 IFU for serovar L1 (440), with the only exception being serovar C (TW-3), with which 99 IFU was detected. There was no cross-reactivity with Chlamydia psittaci (Texas turkey) and Chlamydia pneumoniae (TWAR-183). Bacterial and fungal isolates representing 14 species of normal vaginal flora as well as Neisseria gonorrhoeae gave negative results with the DNA probe when tested at a level of 1.5 X 10(7) CFU/ml. In addition, the DNA probe, a direct fluorescent-antibody stain (DFA) (MicroTrak; Syva Corp., Palo Alto, Calif.), and an enzyme-linked immunosorbent assay (Chlamydiazyme; Abbott Laboratories, North Chicago, Ill.) were compared with culture for the detection of C. trachomatis, using 196 clinical cervical samples. Of the 196 samples, 20 (10%) were culture positive. Of the 176 culture-negative samples, 1 was not evaluated by DNA probe and 4, because of a lack of cellular material, were not evaluated by DFA. The sensitivities of the DNA probe, DFA, and enzyme-linked immunosorbent assay were 60, 75, and 85%, respectively, and specificities were 95, 99, and 97%, respectively. Of the false-positive direct results, there was only one specimen with which more than one direct method was positive, and with this specimen all three direct methods were positive. The majority of false-negative results by the direct methods were from specimens which by the culture method gave <100 IFU per culture.

Chlamydia Infections↗
PubMed1989

Comparison of a single-antigen microimmunofluorescence assay and inclusion fluorescent-antibody assay for detecting chlamydial antibodies and correlation of the results with neutralizing ability.

An inclusion fluorescent-antibody assay (IFA) with McCoy cells infected with Chlamydia trachomatis serovar L2 was compared with a single-antigen (L2) microimmunofluorescence (MIF) assay for the detection of antichalmydial antibodies. A total of 562 serum specimens were tested by both assays, and sera representing a range of titers were tested for their ability to neutralize the infectivity of C. trachomatis. Overall, there was poor correlation between the two assays (r2 = 0.62). With most sera the inclusion IFA was more sensitive. There was better correlation between IFA titer and ability to neutralize the five serovars tested (L2, L3, C, E, and F) than between the MIF assay and neutralization. In summary, the IFA appeared to be more sensitive than the MIF assay for detecting antibodies to C. trachomatis.

Antibodies, Bacterial↗