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Biomedical subjects

H Yukawa

Publications and source records attributed to H Yukawa.

At least 19 recordsLinked to original sources
PubMed2006

Risk factors for dietary variety decline among Japanese elderly in a rural community: a 8-year follow-up study from TMIG-LISA.

OBJECTIVE: To examine the factors related to the decline of dietary variety among the rural community-dwelling Japanese elderly people and the implication on the planning of elderly people's nutritional improvement program in the future. DESIGN: A prospective cohort study during 8-year follow-up from 1992 to 2000. SETTING: This study was conducted in Nangai Village, a rural and mainly agricultural area of Akita Prefecture in the northern part of Honshu, one of four main islands in Japan. SUBJECTS: A total of 417 elderly people (160 men, 257 women) who completed interviews and food intake frequency surveys conducted in 1992, 1994, 1996, 1998, and 2000 were studied. METHODS: Dietary variety and variables potentially associated with dietary variety decline were identified from a face-to-face interview at the baseline and 8-year follow-up surveys. The dietary variety was measured using the dietary variety score (DVS), which covers the 10 main food groups in Japanese meals. RESULTS: During the 8-year follow-up, 36.2% of the subjects showed a decline in dietary variety. Health characteristics also change among the 8-year follow-up and these changes have an effect on the decline of dietary variety. Significant predictors for decline in dietary variety included loss of spouse, deterioration in self-perceived chewing ability, and decrease in intellectual activity score. CONCLUSIONS: Loss of spouse, deterioration in chewing ability, and decline in intellectual activity may increase the risk of decline in dietary variety in community-dwelling Japanese elderly people.

Activities of Daily Living↗
PubMed2005

Acute effects of glucocorticoids on ATP-induced Ca2+ mobilization and nitric oxide production in cochlear spiral ganglion neurons.

Rapid, non-genomic effects of glucocorticoids on extracellular adenosine 5'-triphosphate (ATP)-induced intracellular Ca(2+) concentration ([Ca(2+)](i)) changes and nitric oxide (NO) production were investigated in type I spiral ganglion neurons (SGNs) of the guinea-pig cochlea using the Ca(2+)-sensitive dye fura-2 and the NO-sensitive dye 4,5-diaminofluorescein (DAF-2). Pretreatment of SGNs with 1 microM dexamethasone for 10 min, a synthetic glucocorticoid hormone, enhanced the ATP-induced [Ca(2+)](i) increase in SGNs. RU 38486, a competitive glucocorticoid receptor antagonist eliminated the effects of dexamethasone on the ATP-induced [Ca(2+)](i) increase in SGNs. These acute effects of dexamethasone were dependent on the presence of extracellular Ca(2+), thereby suggesting that dexamethasone may rapidly enhance the Ca(2+) influx through the activation of ionotropic P2X receptors which may interact with glucocorticoid-mediated membrane receptors. Extracellular ATP increased the intensity of DAF-2 fluorescence, indicating NO production in SGNs. The ATP-induced NO production was mainly due to the Ca(2+) influx through the activation of P2 receptors. S-nitroso-N-acetylpenicillamine, a NO donor, enhanced the ATP-induced [Ca(2+)](i) increase in SGNs while L-N(G)-nitroarginine methyl ester (L-NAME), a NO synthesis inhibitor, inhibited it. Dexamethasone enhanced the ATP-induced NO production in SGNs. The augmentation of dexamethasone on ATP-induced NO production was abolished in the presence of l-NAME. It is concluded that the ATP-induced [Ca(2+)](i) increase induces NO production which enhances a [Ca(2+)](i) increase in SGNs by a positive-feedback mechanism. Dexamethasone enhances the ATP-induced [Ca(2+)](i) increase in SGNs which results in the augmentation of NO production. The present study suggests that NO may play an important role in auditory signal transduction. Our results also indicate that glucocorticoids may rapidly affect auditory neurotransmission due to a novel non-genomic mechanism.

Adenosine Triphosphate↗
PubMed2004

Inhibitor-associated transposition events in Corynebacterium glutamicum.

In up to 100% of all bacteria grown in the presence of initially inhibitory concentrations of five diverse inhibitors, an extra copy of the resident insertion element IS 31831 was found in specific chromosomal regions, the sites of which apparently depended on the inhibitor used. Thus, in nine out of nine independently isolated cyanide-associated transpositions, the acquired copy was located within an ORF encoding a protein related to the hypothetical but conserved protein YeiH of Escherichia coli. A putative Sox box upstream of the yeiH gene implicates superoxide as a potential regulator of the gene, a possibility further supported by the finding that superoxide dismutase (SodA) is overexpressed in cells cultured in cyanide-containing medium. Neither the cyanide-associated nor any of the other transposition mutations appeared to confer any discernible phenotypic advantage upon cells grown in the presence or absence of the inhibitors, as revealed most stringently by mixed-cell experiments. An alternative, albeit heterodox, explanation for the emergence of the mutants postulates a very high rate of transpositional activity in the presence of inhibitors. The initial emergence of the mutants was found to depend crucially upon the cell density. Thus, when growth medium was supplemented with 50 mM fluoropyruvate and inoculated to a density of 2 x 10(7) cfu/ml, single colonies with heterogeneous restriction fragment length polymorphisms (RFLPs) were routinely isolated at a frequency of 6 to 16% after 1-2 days of incubation. After 3 days, 10-36% of the colonies showed RFLPs, but the type was now dominated by the fluoropyruvate-specific RFLP, which, at higher resolution, invariably proved to be heterogeneous. This heterogeneity proved that these specific mutants were of multiple origin, indicating that clonal enrichment was irrelevant to their emergence. It is suggested that the presence of the inhibitor induces the development of hyper-transpositional activity, which is regulated by a soluble bacterial product.

Base Sequence↗
PubMed2003

Effect of calcium antagonist on cerebral blood flow and oxygen metabolism in patients with hypertension and chronic major cerebral artery occlusion: a positron emission tomography study.

To evaluate the effect of a calcium antagonist, nilvadipine, on cerebral blood flow and oxygen metabolism, we prospectively examined five ischaemic stroke patients, with both hypertension and chronic major cerebral artery occlusion, using positron emission tomography. The blood pressure showed a significant decrease after 3 months of nilvadipine treatment, the cerebral blood flow in the affected regions showed a significant increase and the oxygen extraction fraction showed a significant decrease. We conclude that nilvadipine is a safe and effective anti-hypertensive agent for patients with both hypertension and chronic major cerebral artery occlusion.

Aged↗
PubMed2001

The ptsI gene encoding enzyme I of the phosphotransferase system of Corynebacterium glutamicum.

The phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) is widespread among bacteria where it mediates carbohydrate uptake and often serves in carbon control. Here we present cloning and analysis of the monocistronic ptsI gene of Corynebacterium glutamicum R, which encodes PTS Enzyme I (EI). EI catalyzes the first reaction of PTS and the reported ptsI was shown to complement the corresponding defect in Escherichia coli. The deduced 59.2-kDa EI of 564 amino acids shares more than 50% homology with EIs from Bacillus stearothermophilus, Bacillus subtilis, and Lactobacillus sake. Chromosomal inactivation of ptsI demonstrated that EI plays an indispensable role in PTS of C. glutamicum R and this system represents a dominant sugar uptake system. Cellobiose was only transported and utilized in adaptive mutants of C. glutamicum R. Cellobiose transport was also found to be PTS-dependent and repressed by PTS sugar glucose.

Amino Acid Sequence↗
PubMed2001

Structure, expression and products of the ribosomal RNA operons of Rhodopseudomonas palustris No. 7.

Rhodopseudomonas palustris strains carry one or two ribosomal rRNA operons, and those with duplicated rrn operons grow faster. The two rrn operons in R. palustris No. 7 are virtually identical over a 54,70-bp stretch containing the genes for 16S rRNA, tRNAile, tRNAala, 23S rRNA and 5S rRNA, as well as the intergenic spacers and part of the extragenic spacer. In R. palustris, unlike most bacteria with multiple rrn operons, the putative promoter sequences of the two operons are highly diverged, suggesting possible functional differentiation. By simultaneous primer-extension analysis of both pre-rRNAs, we detected a two-fold higher level of expression from rrnA under photoautotrophic conditions. Alteration of the conditions of growth leads to changes in the relative levels of expression of the two operons. Within the 5,470-bp segment, only two sequence differences are found between the 23S rRNA genes; one is at the center of the 23S rRNA molecule and affects a site of unknown function, and the other is within or immediately adjacent to sequences involved in processing of the 5' 23S rRNA IVS. In vitro processing of 5' IVS-containing 23S rRNA precursors from each operon does not reveal any detectable difference between them. The 5' ends of the mature 16S, 23S, and 5S rRNAs were determined by primer-extension analysis, and the 3' end of 23S rRNA was determined by RNA linker ligation-mediated cDNA cloning. The 5' and 3' ends of the R. palustris 23S rRNA molecule are extensively processed, suggesting that, unlike the situation in the established eubacterial model, these ends cannot basepair.

Base Sequence↗
PubMed2001

Bacterial phosphotransferase system (PTS) in carbohydrate uptake and control of carbon metabolism.

More than 20 carbohydrates may be transported into the bacterial cell by the phosphoenopyruvate:carbohydrate phosphotransferase system (PTS) that is widely spread among bacteria. The PTS consists of two cytoplasmic energy-coupling proteins (Enzyme I and HPr) and a range of carbohydrate-specific Enzymes II, which catalyze concomitant carbohydrate translocation and phosphorylation. The phosphorylation status of PTS components reflects the availability of carbohydrates and the energy conditions of the cell. In many bacteria, PTS and the associated proteins convert this information to signals, which transduced through different mechanisms lead to phenomena of catabolite repression, inducer control or chemotaxis. These features of PTS provide bacteria with an integrated system, which assures optimal utilization of carbohydrates in complex environments. Furthermore, some bacteria evolved parallel systems that serve a regulatory functions, but apparently do not catalyze the carbohydrate transport. Here we review the findings that recently advanced the understanding of various aspects of PTS-dependent carbohydrate transport and regulation of bacterial catabolism.

Journal Article↗
PubMed2001

[Clinical study on prognostic factors in thyroid carcinoma].

We treated 227 patients, 45 men and 182 women, with thyroid carcinoma at our hospital from 1984 to 1998. Of these, 177 had papillary carcinoma and 50 follicular carcinoma. The extent of resection was based on tumor size in papillary carcinoma but not follicular carcinoma, and 70% of carcinoma patients underwent hemithyroidectomy. Neck lymph nodes were resected in 93.2% of papillary carcinoma patients, with D1 neck dissection in 45.7% and D2 or D3 neck dissection in 47.5%. In contrast, 70% of follicular carcinoma patients with lymph node resection had D1 dissection. Locoregional recurrence was noted in 22 patients and distant metastasis in 6 cases. Nonsurvivors numbered 17, 12 papillary and 5 follicular carcinoma patients, died of their primary disease. Almost all deaths were in patients with advanced disease, pT3 in 3, pT4 in 10, N1a in 3 and N1b in 8. The prognostic factors for papillary carcinoma were extracapsular spread, age, and distant metastasis, while the only factor for follicular carcinoma was distant metastasis. The 5-year survival for patients with papillary carcinoma was 93.0% and 10-year survival 88.8%, compared to 5-year survival for 93.5% of follicular carcinoma patients and 10-year survival for 93.5%.

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↗
PubMed2001

[Dietary calcium and women's health].

Among the many possible contributors to primary osteoporosis, calcium deficiency is currently considered to be most important. The average calcium intake of the Japanese, by national nutrition survey, however, is now around 568 mg/day which is much lower in women than the recommended dietary allowances of calcium proposed by the Ministry of Health and Welfare, and than those in western countries. Milk is a food with a high ratio of nutrients to energy, and it is also primarily identified as an excellent source of calcium. The significance of dietary calcium intake and milk consumption for bone health of women should be provided by mass health education and individual guidance in a practice of public health.

English Abstract↗
PubMed2000

Divergent mechanisms of 5' 23S rRNA IVS processing in the alpha-proteobacteria.

Widespread occurrence of a separate small RNA derived from the 5'-end of 23S rRNA and of an intervening sequence (IVS) which separates this domain from the main segment of 23S rRNA in the alpha-proteobacteria implies that processing reactions which act to excise the IVS are also maintained in this group. We previously characterized the first example of processing of this IVS in Rhodopseudomonas palustris, which is classified with the Bradyrhizobia In this case, IVS excision occurs by a multistep process and RNase III appears to act at an early step. Here, we characterize in vivo and in vitro IVS processing in two other related, but phenotypically distinct, Bradyrhizobia We also examine in vivo and in vitro processing of rRNA precursors from a more distantly related alpha-proteobacterium, Rhodobacter sphaeroides which produces a separate 5' 23S rRNA domain but has different sequences in the 5' 23S rRNA IVS. The details of the in vivo processing of all of the Bradyrhizobial rRNAs closely resemble the R. palustris example and in vitro studies suggest that all of the Bradyrhizobia utilize RNase III in the first step of IVS cleavage. Remarkably, in vivo and in vitro studies with R.sphaeroides indicate that initial IVS cleavage uses a different mechanism. While the mechanism of IVS cleavage differs among these alpha-proteobacteria, in all of these cases the limits of the internal segments processed in vivo are almost identical and occur far beyond the initial cleavage sites within the IVSs. We propose that these bacteria possess common secondary maturation pathways which enable them to generate similarly processed 23S rRNA 5'- and 3'-ends.

Alphaproteobacteria↗
PubMed2000

Adenovirus-mediated gene transfer of basic fibroblast growth factor promotes the survival of primary-cultured rat neuronal cells.

We constructed two replication-deficient recombinant adenovirus vectors coding human basic fibroblast growth factor (bFGF), one with and one without the interleukin-2 (IL-2) secretory signal sequence and examined their neurotrophic effects on primary neuronal cells in vitro. The primary neuronal cells were successfully infected at a high efficiency with the adenovirus vectors. bFGF protein was detected in the culture medium of the neurons infected with both these vectors. The cells infected with the bFGF-expressing adenovirus containing the IL-2 signal sequence showed 2- to 10-fold higher levels of secretion levels than cells infected with the native bFGF-expressing adenovirus alone. Both bFGF-expressing vectors augmented the survival of primary neuronal cells in an in vitro culture, compared with a mock infection or control virus infection. Notably, the cells infected with the bFGF-expressing adenovirus containing the IL-2 signal sequence were markedly enhanced cell survival in the early phase of the culture, compared with the control cells and even those infected with the bFGF-expressing adenovirus without the IL-2 signal sequence. However, in the late phase of neuronal culture, neither viral vector could support the cell survival. In contrast the co-infection of the bFGF-expressing vector with a Bcl-xL-expressing vector was extremely effective on neuronal survival.

Adenoviridae↗
PubMed2000

Purification, cloning, and three-dimensional structure prediction of Micrococcus luteus FAD-containing tyramine oxidase.

The FAD-containing tyramine oxidase enzyme and gene from the Gram (+) bacterium Micrococcus luteus were isolated, and computer prediction was used to propose a preliminary 3D model of the protein. A 2.8-kb Sau3AI fragment containing the structural gene of tyramine oxidase was cloned from a M. luteus genomic DNA library. The 1332 bp gene encodes a protein of 443 amino acids, with a calculated molecular mass of 49.1 kDa. The enzyme was found to be a homodimer with a molecular weight of 49,000. It oxidizes tyramine, adrenaline, 3-hydroxytyramine, dopamine, and noradrenaline, and was reversibly inhibited by FAD-containing monoamine oxidase A and B specific inhibitors. Sequence comparison show that tyramine oxidase is smaller than other FAD-amine oxidases but that it contains well-conserved amino acid residues reported in all other FAD-amine oxidases. A hypothetical three-dimensional structure of tyramine oxidase has also been proposed based on secondary structure predictions, threading, and comparative modeling.

Amino Acid Sequence↗
PubMed2000

Indole-inducible proteins in bacteria suggest membrane and oxidant toxicity.

Oxidant toxicity of indole was demonstrated by the induction of alkylhydroperoxide reductase subunit C (AhpC) in Escherichia coli K12 and by the constitutive overproduction of AhpC in a variant of E. coli JM109 with enhanced resistance to indole. Oxidant toxicity was also indicated in an indole-adapted variant of Brevibacterium flavum by the indole-inducible overproduction of a novel 36-kDa protein with N-terminal sequence similarity to proteins involved in superoxide and singlet oxygen resistance. It is proposed that indole dissolved in membrane lipids, which caused membrane derangement and enabled direct interaction of redox-cycling isoprenoid quinones and dioxygen, resulting in the generation of superoxide. A direct indication of membrane derangement in E. coli may be the indole-inducible overproduction of spheroplast protein y (Spy).

Amino Acid Sequence↗
PubMed2000

Indolyl carboxylic acids by condensation of indoles with alpha-keto acids.

The novel indole derivatives 2,2-bis(3,3'-indolyl)propionic acid (1); 1,1,1,-tris(3,3',3"-indolyl)ethane (2); and 2,2-bis(3, 3'-indolyl)isocaproic acid (3) were isolated from solvent extracts of indole-supplemented supernatants of Escherichia coli and corynebacteria. The compounds were also obtained by chemical synthesis: compounds 1 and 2 from indole and pyruvic acid and compound 3 from indole and alpha-ketoisocaproic acid, following incubation at 37 degrees C in aqueous medium. Tryptophan and pyruvic acid gave the novel 2-(2-tryptophanyl)lactic acid (4). The condensation reaction between indoles and alpha-keto acids was of general nature, and the mild reaction conditions suggested it may proceed in vivo. Examples for endogenous occurrence may be the neuro-degenerative diseases phenylketonuria and maple syrup urine disease, both characterized by elevated blood levels of alpha-keto acids.

Brevibacterium↗
PubMed2000

Adenoviral gene transfer of basic fibroblast growth factor promotes angiogenesis in rat brain.

Cerebral ischemic disease often causes morbidity and mortality, while the induction of new blood vessels is expected to provide a therapeutic effect in this occlusive cerebrovascular disease. In this study, we utilized two replication-deficient adenoviral vectors containing cDNA from basic fibroblast growth factor (bFGF), a well-known angiogenic factor, and examined whether biological angiogenic activity of adenovirally gene-transferred bFGF could be observed in the rat brain. One vector contained native cDNA from bFGF without the secretory signal sequence and the other contained the same cDNA fused with an interleukin-2 secretory signal sequence. After ventricular administration of these viral vectors, gene-transferred cells demonstrated a high immunoreactivity against the anti-bFGF antibody and a remarkably high concentration of bFGF was detected in the cerebrospinal fluid. A semiquantitative analysis of angiogenic activity revealed that bFGF gene transfer induced angiogenesis in normal rat brains, with a more pronounced angiogenic effect seen with the vector of a secreted form than with the vector without a secretory signal sequence. These results suggest that bFGF gene transfer using these adenoviral vectors might be useful for the treatment of ischemic cerebrovascular disease.

Adenoviridae↗
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↗