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S Shinkai

Publications and source records attributed to S Shinkai.

At least 37 records · Page 2Linked to original sources
PubMed2001

Polysaccharide--polynucleotide complexes. 2. Complementary polynucleotide mimic behavior of the natural polysaccharide schizophyllan in the macromolecular complex with single-stranded RNA and DNA.

Schizophyllan is an extracellular polysaccharide consisting of a beta-1,3-D-glucan main chain and exists as a triple helix in water and as a single chain in dimethyl sulfoxide (DMSO). When the single chain of schizophyllan (s-SPG) was mixed with poly(C), poly(A), poly(dA), or poly(dT), they form a macromolecular complex. On the other hand, poly(G), poly(U), poly(I), poly(dG), and poly(dC) do not. This nucleotide specificity evidences that the hydrogen bonds are essential to form the complex, because the former nucleotides have an unoccupied hydrogen-bonding site and the latter ones use the hydrogen-bonding sites in the intramolecular aggregation (i.e., such as the G quartet for poly(G) and poly(dG) and the U hairpin for poly(U)). The hypochromic effect and the increment in the circular dichroism (CD) intensity are observed in accordance with the complex formation. These facts indicate that the base stacking is enhanced in the complex. The solvent-composition (DMSO/water) dependence demonstrates that the hydrophobic interaction is important to form the complex as well as the hydrogen-bonding interaction. With increasing temperature the complex dissociates cooperatively and the melting curve enables the thermodynamic parameters to be evaluated (delta H = -60 to 70 kcal mol-1 and delta S = -150 to 200 cal mol-1 K-1). These values are comparable with those for double helix DNA. Namely, the complex can be characterized by enhancement of the base stacking, cooperative dissociation, the similar thermodynamic parameters to DNA, and combination of the hydrogen-bonding and hydrophobic interactions to form the higher-order structure. These facts surprisingly coincide with characters of the double helix of DNA. In other words, the s-SPG molecule behaves as if it were a complementary polynucleotide chain for the corresponding polynucleotide. Furthermore, stoichiometric study suggested that the complex structure is a triple helix consisting of two s-SPG and one poly(C) or poly(A) chains.

Carbohydrate Conformation↗
PubMed2001

Application of schizophyllan as a novel gene carrier.

Schizophyllan (SPG) is a kind of beta-1,3-glucan which has glucose side chain through a beta-1,6-glycosil bond (Fig. 1). It was found that SPG could form complex with single stranded polynucleotides. SPG forms triple stranded complex with single stranded RNAs thorough hydrogen bonding and hydrophobic interaction. It was found tht polynucleotide was protected from nuclease attacking to form the complex with SPG, and SPG enhanced antisense efficient.

DNA, Antisense↗
PubMed2001

A novel technique to specifically separate RNAs by Schizophyllan.

Schizophyllan (SPG) is a kind of beta-1,3-glucan which has glucose side chain through a beta-1,6-glycosil bond (Fig. 1). It was found that SPG could form complex with single stranded polynucleotides. SPG complexes with single stranded RNAs that have similar helix parameter to triple stranded SPG thorough hydrogen bonding and hydrophobic interaction. We prepared single stranded SPG appended gel supports. It worked as affinity column for polynucleotides. Poly(C) and poly(A) was retained in the SPG column at low temperature, though poly(G) passed by SPG column without interaction. RNAs trapped in the SPG appended column were released by changing elution buffer under mild condition. This SPG column could use to separation of mRNA which has poly(A) tail. The results obtained led to the conclusion that SPG which has neither cation charge or nucleic base can play as RNA separation material.

Chromatography, Affinity↗
PubMed2001

[Survey of consciousness of community residents regarding the community life of disabled persons with service dogs].

PURPOSE: Service dogs have received much attention as effective choices for promoting participation in society of disabled persons. The purpose of this study was to obtain the fundamental data to prepare guidelines regarding service dogs use in community life, by making clear the problems in terms of public health and community welfare through a survey of attitudes towards service dogs in community residents. METHODS: Study 1 was conducted as follows. The subjects were 423 community residents between their teens and seventies who participated in health and welfare lectures in 4 metropolitan areas. A questionnaire survey was conducted just after watching a promotion video about service dogs, including several items on aspects not accept, were anxious about or were unpleasant in the case of community life of a disabled person and a service dog. Study 2 was as follows. A questionnaire survey was conducted inside a supermarket in the central part of Tokyo. One group of subjects were 103 shopping customers who witnessed a shopping scene featuring a disabled person with her service dog, and the other subjects were 84 customers who were not witnessed to the scene. The same survey was simultaneously performed for impression about the shopping scene. RESULTS: Study 1 showed that 31.8% of all the respondents replied that they had some knowledge of service dogs before watching the video. A total of 20.4% (32.5% of the elderly) replied that there were places where service dogs should not enter. Concretely speaking, these included restaurants for 7.3-22.5% and medical institutions for 8.5-12.5% of the respondents. A third of all the respondents (51.3% of older persons) replied they could not endure some actions by service dogs, concretely "carrying food in the mouth" was highly pointed out by 27.3%. Zoonosis (15.3-19.0%), hair scattering (9.5-21.3%), injuries (4.4-7.4%) were also pointed out as main sources of anxiety or uncomfortable feelings. Such negative opinions were especially apparent among those aged 60 years and older. Also, 44.1% knew some disabled person. Cross tabulation showed those who had experience of taking care of a dog were significant less anxious about "vague anxiety or discomfort," and "zoonosis" than those who had not (P < 0.01). On the other hand, most of both witness (79.6%), and non-witness groups (81.0%) replied that it was heartwarming that the service dog assisted with shopping. None expressed discomfort about the presence of "service dog" inside the supermarket. In terms of carrying a commodity in the mouth, 92.2% and 89.1% in both groups replied that they don't mind, especially if safety was guaranteed for public health, and 91.3% and 95.2% in both groups replied that they had no other problems. Moreover, none of them would not entering stores. Significant differences were seldom in replies between the witness and non-witness groups. CONCLUSION: Although the respondents were extremely affirmative regarding the image of service dogs, it became clear that anxiety about public health aspects such as "zoonosis" or "utilization of medical institutions" was persisting. On the whole, negative opinions were more apparent in the elderly.

Adolescent↗
PubMed2001

[Incidence and prognosis of, and risk factors for the home-bound in a community elderly population].

This longitudinal study examined numbers of homebound and bed bound individuals over time, and risk factors in a rural community elderly populations. A total of 731 older persons who needed no assistance of another person in traveling from their homes participated in the baseline survey in 1992 and were assessed annually for their ability to travel for subsequent six-years. We defined operationally a homebound status as the necessity for assistance of another person to be able to leave home, but without being bedbound. During the follow-up period, 86 homebound (23.7 per 1,000 person-years) and 32 bedbound cases (8.4 per 1,000 person-years) were noted, the former being 2.8 times more likely to occur. Of the newly bound cases 26% returned to a state capable of leaving home by themselves one year later, and maintained this independent living level even two years later. Of the other cases who remained as homebound or bedbound one year later, only one (1/31) had returned to independent living after two years; most of them became bedbound at home, hospital admitted or deceased. Stepwise multiple logistic regression analysis showed that independent risk factors for the homebound include older age, male gender, slower walking speed, history of hospital admission in the previous year, lower masticatory ability, and higher level of serum beta 2-microglobin. These results indicate that health promotion programs for prevention of becoming homebound among community elderly people should target more intensively assistance to maintaining walking and masticatory ability. In addition, public health professionals should pay more attention to elderly people shortly after hospital discharge.

Activities of Daily Living↗
PubMed2000

Sol-gel polycondensation in a cyclohexane-based organogel system in helical silica: creation of both right- and left-handed silica structures by helical organogel fibers.

Chiral amide- and urea-type organic gelators (1-6), based on cyclohexanediamine, have been prepared, and the superstructures of the organogels were evaluated by circular dichroism (CD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The CD spectrum of the amide-based organogel system 1+2 exhibited a negative sign for the first Cotton effect, indicating that the dipole moments in the gelator aggregate orient into an anticlockwise direction. In contrast, the system 3+4 has a positive sign for the first Cotton effect, indicating that they orient into a clockwise direction. In the mixture of urea- and amide-based organogels, CD spectra of 5+2 and 6+4 revealed negative and positive signs, respectively. The helical structure of the amide-based organogels 1+2 and 3+4 clearly showed left- and right-handed structures, respectively, by SEM. To transcribe the chiral, helical structures of the organogels into silica gel, the sol-gel polycondensation of tetraethoxysilane (TEOS) was carried out in acetonitrile or ethanol. Very surprisingly, the left- and right-handed structures of the silica can be created by transcription of left- and right-handed structures of the organogels 1+2 (R enantiomer) and 3+4 (S enantiomer), respectively. In addition, in the mixture systems of urea- and amide-based organogels, the right- and left-handed structures of the organogels 5+2 (R enantiomer) and 6+4 (S enantiomer) were precisely transcribed into the silica structure. The findings suggest that the sol-gel polycondensation proceeds along the surface of the helical structure of the organogels. We therefore believe that the sol-gel polycondensation by means of molecular assembly templates abundantly built in the organogel phase is a new strategy to create superstructured silica materials.

Journal Article↗
PubMed2000

Ag+ labeling: a convenient new tool for the characterization of hydrogen-bonded supramolecular assemblies by MALDI-TOF mass spectrometry.

Herein we describe our results on the characterization of a wide variety of different hydrogen-bonded assemblies by means of a novel matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique with Ag+ labeling. The labeling technique with Ag+ ions is extremely mild and provides a nondestructive way to generate charged assemblies that can be detected by mass spectrometry. Up to now more than 25 different single (1(3).2(3)), double (3(3).2(6)), and tetrarosettes (4(3).2(12)) have been successfully characterized by the use of this method. The success of the method entirely depends on the presence of a suitable binding site for the Ag+ ion. A variety of functionalities has been identified that provide strong binding sites for Ag+, either acting in a cooperative way (pi-arene and pi-alkene donor functionalities) or individually (cyano and crown ether functionalities). The method works well for assemblies with molecular weights between 2,000 and 8,000 Da, and most likely far beyond this limit.

Journal Article↗
PubMed2000

A self-assembled porphyrin-based dimeric capsule constructed by a Pd(II)-pyridine interaction which shows efficient guest inclusion

Novel self-assembled molecular capsules were constructed from two moles of pyridine-containing porphyrin derivatives and four moles of Pd(II) complexes utilizing a pyridine-Pd(II) interaction. The (1)H NMR spectral studies established that these self-assembled molecular capsules 5 and 6 have a highly symmetrical D(4)(h)() structure as well as a large inside cavity. It was shown that molecular capsule 6 can include a large bipyridine guest by a two-point simultaneous pyridine-Zn(II) interaction.

Journal Article↗
PubMed2000

Direct comparison of electron transfer properties of two distinct semisynthetic triads with non-protein based triad: unambiguous experimental evidences on protein matrix effects.

In order to understand the roles of protein matrix in electron transfer processes (ET) within biological systems, a heme-based donor (Zn-heme: ZnPP)-sensitizer (Ru2+(bpy)3)-acceptor (cyclic viologen: BXV4+) triad 1 was used as a probe molecule. Two semi-synthetic systems, Cyt-b562(1) and Mb(1), in which the triad is incorporated into cytochrome b562 (Cyt-b562) or into myoglobin (Mb), were constructed by cofactor reconstitution. These two semi-synthetic proteins were compared with the triad itself (i.e., without the protein matrix) using absorption spectroscopy, steady state emission and excitation studies, laser flash photolysis experiments, and molecular modeling. Photoexcitation of the ZnPP moiety of Cyt-b562(1) or Mb(1) leads to a direct ET from the triplet state of ZnPP state (3ZnPP) to BXV4+ to generate a final charge-separated (CS) state, Cyt-b562(Zn+)-Ru2+-BXV3+* or Mb(Zn+)-Ru2+-BXV3+*. On the other hand, direct ET from the excited ZnPP moiety to the BXV4+ moiety is also involved in 1 in the absence of the protein matrix, but the excited state of ZnPP involved is not 3ZnPP, but the singlet excited state (1ZnPP) in this pathway. When the Ru2+(bpy)3 moiety of Cyt-b562(1) or Mb(1) is excited, a stepwise ET relay occurs with the ion-pair, Cyt-b562(Zn)-Ru3+-BXV3+* or Mb(Zn)-Ru3*-BXV3+*, as an intermediate, leading to the same final CS state as that generated in the direct ET pathway. The lifetimes of the corresponding final CS states were determined to be 300 ns for 1 in the absence of the protein matrix, 600-900 ns for Cyt-b562(1) and 1.1-18 micros for Mb(1), the values of which are greatly affected by the protein matrix. Molecular modeling study of the three systems consistently explained the differences of their photophysical behavior.

Cytochrome b Group↗
PubMed2000

Phase separation in the mixture of schizophyllan and poly(ethylene oxide) in aqueous solution driven by a specific interaction between the glucose side chain and poly(ethylene oxide).

We found that the mixture of schizophyllan and poly(ethylene oxide) in aqueous solution underwent phase separation at around 3-4 degrees C, and this temperature was independent of both polymer concentration and the difference in poly(ethylene oxide) molecular weight (Mw 6000 and 70,000). The phase-separation took place at the same temperature at which the optical rotation changed. Since the optical rotation change is ascribed to the difference in the nature of hydrogen bonding between the schizophyllan side chain and water, the phase separation is also considered to be due to an interaction between poly(ethylene oxide) and schizophyllan. The phase-separation temperature increased on changing H2O to D2O in accordance with a change in the optical rotation, confirming the specific interaction essential for the phase separation.

Chemical Phenomena↗
PubMed2000

Incorporation of artificial receptors into a protein/peptide surface: a strategy for on/off type of switching of semisynthetic enzymes.

Recent developments in new bioorganic methodologies have greatly facilitated the site-specific incorporation of non-natural amino acids into the protein framework. It is now desirable for chemists to explore promising concepts based on chemistry for regulation and extension of functions of naturally occurring enzymes using non-natural molecules, in order to promote the new trends in protein/enzyme engineering. This article demonstrates that the concepts of host-guest (or supramolecular) chemistry, which have been developed over the last few decades, provide powerful tools for the artificial control of the functions of native proteins and enzymes.

Amino Acid Sequence↗
PubMed2000

Regulatory factors of medical care expenditures for older people in Japan--analysis based on secondary medical care areas in Hokkaido.

For the purpose of clarifying determinants of medical care expenditure for older people in Japan, we analyzed the data on medical care expenditure for older people in 21 secondary medical care areas in Hokkaido, the second largest island of Japan. The annual amount of medical expenditure per insured older person can be reduced into three components: annual number of medical care bills per insured older person days of hospitalization or visits per medical care bill and amount of medical expenditure per day and per insured older person. The 21 secondary medical care areas in Hokkaido showed large differences in per capita amount of both inpatient and outpatient medical expenditures for older people. Per capita inpatient medical expenditure for men and women correlated positively with the days of hospitalization per bill and the per capita number of inpatient medical care bills per year, but inversely with the per capita amount of expenditure per day of hospitalization. The same held true for outpatient medical expenditure for men, but for women outpatient medical expenditure correlated positively with all three components. Multiple regression analysis indicated the more powerful effects of medical care demand or supply on inpatient medical expenditure, on the other hand, not much powerful effects of every index were indicated on outpatient medical expenditure.

Aged↗
PubMed2000

Walking speed as a good predictor for the onset of functional dependence in a Japanese rural community population.

OBJECTIVE: to investigate and compare the predictive values of four physical performance measures for the onset of functional dependence in older Japanese people living at home. DESIGN: a population-based prospective cohort study. SETTING: Nangai village, Akita Prefecture, Japan. METHODS: out of the population aged 65 years and older living in Nangai (n = 940) in 1992, we measured hand grip-strength, one-leg standing, and usual and maximum walking speeds in 736 subjects who were independent in the five basic activities of daily living. Their functional status was assessed each year for the subsequent 6 years. The outcome event was the onset of functional dependence, defined as a new disability in one or more of the five basic activities of daily living, or death of a subject who had shown no disability at the previous follow-up. RESULTS: even after controlling for age, sex and a number of chronic conditions, lower scores on each baseline performance measure showed increased risk for the onset of functional dependence. Maximum walking speed was most sensitive in predicting future dependence for those aged 65-74 years, while usual walking speed was most sensitive for people aged > or = 75 years. CONCLUSION: walking speed was the best physical performance measure for predicting the onset of functional dependence in a Japanese rural older population.

Activities of Daily Living↗
PubMed2000

[Alcohol consumption and change of activity of daily living among the elderly living in an urban community].

Alcohol consumption has both adverse and beneficial effects on survival. We examined the baseline status of alcohol consumption and the changes of instrumental activity of daily living (I-ADL) by a prospective survey for the elderly living in an urban community who were participants in the "Longitudinal and Interdisciplinary Study on Aging by the Tokyo Metropolitan Institute of Gerontology (TMIG-LISA)". Detailed information on alcohol intake was collected during a structured interview. At a baseline survey in 1991, 1) the frequency of current drinkers decreased lineally by age. 2) the most popular alcohol beverage was beer for both sexes and average ethanol intake per day were 41 (10-45) g in men and 24 (8-28) g in women. Current drinkers had significantly stronger grip strength, higher velocity in maximum walking and higher score on the TMIG Index of Competence, designed to measure the higher-level competence in elderly community residents. After 4 years follow-up, in 1995, 73.3 percent of the participants completed the examination. They were classified into five categories as "current drinkers", "lifetime abstainers", "beginning to drink during follow-up period", "quit drinking during follow-up period" and "quit drinking at baseline". The decline of I-ADL was significantly greater among the elderly who "quit drinking during follow-up period" than "current drinkers". Further "current drinkers" had significantly lower decline of I-ADL than "lifetime abstainers". Our findings show beneficial effects of moderate alcohol intake in the maintenance of a higher level of competence in the elderly living in a community.

Activities of Daily Living↗
PubMed2000

[A comparison between three methods to investigate falls among the elderly living in the community].

PURPOSE: Interview survey is the often selected method to investigate falls among the elderly. However, the reliability of data obtained by that method has not be confirmed. The aim of this study is to clarify the number of intervals of recollection that should be specified to ensure accurate data when we investigate falls by using interview surveys among the elderly. METHODS: We carried out a total health survey among the elderly in Shigenobu town, and reported about the frequency of falls and its relating factors. Sex, age, walking ability over a distance of 1 km and hospitalization experience for past 1 year were related to falls significantly. In this study, we set 3 groups matching for the above factors in addition to history of falls during the preceding a year, and for one year we asked about falls every month for the first group (116 participants), every 3 months for the second group (116 participants) respectively. The third group (118 participants) was asked once at the end of this study. These three groups totaled 350 persons who were participants of physical fitness measurements that we carried out in Shigenobu town. The existence of falls was investigated by mail, and the nonrespondents were questioned by direct telephone calls. RESULTS: For reasons such as death, moving out, hospitalization and answer denial, persons whose answer was not obtained were excluded from the analysis. Finally, 87.1% in the 1st group, and 89.7% in the 2nd group and 96.6% in the 3rd group were analyzed. Statistically significant difference for the above factors related to falls did not exist among the 3 groups. Annual incidence for falls tended to be more frequent in the 1st group that in the 3rd group (20.5% in the 1st group, 15.9% in the 2nd group and 6.4% in the 3rd group) in males. In females, such a difference was not observed. (26.3% in the 1st group, 18.3% in the 2nd group and 20.9% in the 3rd group). CONCLUSIONS: There were no significant differences for the factors related to falls in 3 groups, therefore, the groups had almost similar backgrounds. In men, the difference of annual reported incidence between the 1st group and the 3rd group may be due to differences in the method of recollection.

Accidental Falls↗