Biomedical subjects

H Satoh

Publications and source records attributed to H Satoh.

At least 109 records · Page 6Linked to original sources

PubMed2001

Water-soluble chlorophyll protein in Brassicaceae plants is a stress-induced chlorophyll-binding protein.

Two kinds of water-soluble chlorophyll (Chl) proteins (WSCPs) have been found, e.g., a WSCP from Chenopodium, Atriplex, Polygonum, and Amaranthus species (class I) and that from Brassica, Raphanus, and Lepidium species (class II). Classes I and II WSCPs differ mainly in their photoconvertiblity. Class I WSCPs show a light-induced absorption change, whereas Class II WSCPs do not. The molecular and functional properties of Class I WSCP are largely uncertain. On the other hand, recent studies on the adaptation of plants to osmotic stress revealed the participation of drought-stress induced proteins with molecular masses of 20-22 kDa possessing a sequence similarity with class II WSCPs. This mini review focuses on the molecular signature of class II WSCPs. The physiological function of class II WSCPs has not been clarified either, but, their water-solubility, low Chl content, and stress-inducibility suggested little contribution to photosynthesis. Several molecular properties predicting its physiological role are as follows. The WSCP tetramer, may have only one or no Chl molecules in each subunit. All WSCPs possess a motif for Künitz-type proteinase inhibitor family in their sequence. WSCP is induced by drought- and heat-stresses suggesting its protective role during stress conditions. Monomeric recombinant apo-WSCP is able to remove Chls from the thylakoid membrane in aqueous solution and form into a tetramer. Brassica-WSCP contains a signal sequence targeted to endoplasmic reticulum. The highly conserved, C-terminal region is missing in the mature WSCP. Possible functions of class II WSCPs in plant tissues are discussed.

Adaptation, Physiological↗

PubMed2001

Factors affecting the difference between screening and home blood pressure measurements: the Ohasama Study.

OBJECTIVE: To establish the factors affecting the difference between screening and home blood pressure measurements. DESIGN: A cross-sectional study. SETTING: General population in a rural Japanese community, Ohasama, Japan. PARTICIPANTS: There were 1,789 community-based subjects aged > or =40 years, for whom blood pressure was measured at screening site (screening blood pressure) and at home (home blood pressure). RESULTS: Multiple stepwise regression analysis of all subjects demonstrated that screening pulse pressure was positively associated with the difference between screening and home blood pressure measurements for systolic blood pressure. Age, the use of antihypertensive medication, and smoking status were negatively associated with the difference between measurements of both systolic and diastolic blood pressure. CONCLUSION: We have demonstrated that age, smoking, antihypertensive medication, and screening pulse pressure are independent predictors of the magnitude of the difference between screening and home blood pressure measurements, suggesting that the necessity to consider these factors, for the detection of the subjects who may be inappropriately treated or misjudged following screening blood pressure measurements.

Adult↗

PubMed2001

Usefulness of home blood pressure measurements in assessing the effect of treatment in a single-blind placebo-controlled open trial.

OBJECTIVES: Reproducibility of home blood pressure measurements (HBP), and the placebo effect on HBP, were examined to establish the number of subjects required in order to observe a significant antihypertensive effect of a drug for a comparative study between placebo and active treatment. METHODS: Reproducibility of HBP (n = 172 for systolic blood pressure and n = 137 for diastolic blood pressure) and the placebo effect on HBP (n = 35 for systolic and n = 42 for diastolic blood pressure) were examined using a semi-automatic electronic device on untreated hypertensive subjects during 21 consecutive days of measurements. From these two studies, the number of subjects required in order to observe a significant antihypertensive drug effect was assessed. In both studies, measurements from the first 3 days were excluded from the analysis. RESULTS: Reproducibility, defined as the difference between the initial 5 day average (days 4-8) and the last 5 day average (days 17-21) was -1.9 +/- 7.0/-1.4 +/- 4.8 mmHg (mean +/- SD), indicating high reproducibility with a minimal regression to the mean effect. A placebo was administered after the 8 day run-in period. The difference between the initial 5 day average (days 4-8) and the last 5 day average (days 17-21) was compared. The mean difference was 1.1 +/- 6.2/0.2 +/- 5.7 mmHg, suggesting that there was a minimal, if any, placebo effect. As determined by the power calculations, based on the standard deviations of the tests for reproducibility and the placebo effect, nine of 13 subjects are required to show that a 9/5 mmHg decrease in systolic HBP/diastolic HBP (50% of estimated effective decrease in systolic HBP/diastolic HBP according to the guidelines for clinical trials in Japan) is statistically significant CONCLUSIONS: The results suggest that the HBP measurement is highly reproducible and that there is a minimal, if any, placebo effect. These characteristics of HBP contribute to minimizing the number of subjects necessary for assessment of antihypertensive drug effects in comparative studies between an active treatment and placebo.

Adult↗

PubMed2001

Aldosterone synthase gene (CYP11B2) C-334T polymorphism, ambulatory blood pressure and nocturnal decline in blood pressure in the general Japanese population: the Ohasama Study.

OBJECTIVE: The C-344T polymorphism in the 5'-flanking region of the aldosterone synthase (CYP11B2) gene has been suggested to be associated with hypertension and disturbed circadian blood pressure (BP) rhythm through its effect on aldosterone synthesis. However, previous findings on this topic have been inconsistent. DESIGN: A cross-sectional study. SUBJECTS AND METHODS: We investigated the CYP11B2 C-344T genotype in 802 subjects, aged 40 and over, in a Japanese community, who gave written informed consent and were monitored for 24 h ambulatory BP. RESULTS: The frequencies of the CC, CT, and TT genotypes in these Japanese subjects were 0.14, 0.44, and 0.42, showing a higher frequency of the T allele (0.64) than in Caucasians. Although there was no significant difference in 24 h ambulatory BP levels among the genotypes, the nocturnal decline in BP was significantly greater in the CC homozygous subjects than in other subjects (P = 0.0065 for systolic and P = 0.031 for diastolic decline in nocturnal BP). Detailed analyses demonstrated that this association was significant only in aged (60 years and over) or male subjects. The prevalence of previous cardiovascular disease was significantly less in these subjects with the CC genotype than in those with the TC and TT genotypes, although age, body mass index, male gender, smoking, use of alcohol and antihypertensive medication did not differ among the three genotypes. There was no significant difference among the three genotypes in biochemical and hormonal parameters. CONCLUSION: Although the C-344 T polymorphism of CYP11B2 did not directly influence the level of 24 h BP, the CC genotype was associated with decreased nocturnal BP in elderly or male Japanese. Since prevalence of previous cardiovascular disease was significantly less in homozygous CC subjects, greater nocturnal BP decline in this genotype appears to be beneficial in the circadian BP rhythm.

Aged↗

PubMed2001

Predictive values of automated blood pressure measurement: what can we learn from the Japanese population - the Ohasama study.

BACKGROUND: Measurements of ambulatory blood pressure (ABP) and of home blood pressure (HBP) as an adjunct to casual/clinic blood pressure (CBP) measurements are currently widely used for the diagnosis and treatment of hypertension. We have monitored a rural cohort of people from the population of Ohasama, Japan, with respect to their prognosis and have previously reported that ABP and HBP are superior to CBP for the prediction of cardiovascular mortality. One reason that CBP is a poor predictor of prognosis is that it incorporates several biases, including the white-coat effect. METHODS AND RESULTS: We examined the prognostic significance of white-coat hypertension for mortality and found that the relative hazard for the overall mortality of patients with white-coat hypertension was significantly lower than that for true hypertension. Short-term blood pressure variability has recently attracted attention as a cause of target-organ damage and cardiovascular complications. Our results confirmed that short-term blood pressure variability (as measured every 30 min) was independently associated with cardiovascular mortality. In addition, research has recently focused on isolated systolic hypertension and pulse pressure as independent risk factors for poor cardiovascular prognosis. The Ohasama study also clearly demonstrated that isolated systolic hypertension and increased pulse pressure, as assessed by HBP, were associated with an increase in the risk of cardiovascular mortality. Circadian blood pressure variation is characterized by a diurnal elevation and a nocturnal decline in blood pressure. We therefore compared morbidity from stroke between dippers (subjects who show an ordinal nocturnal dipping of blood pressure) and non-dippers (those with a diminished nocturnal dipping or nocturnal elevation of blood pressure [inverted dippers]) in the Ohasama study. The incidence of stroke increased with an increased length of observation in dippers using antihypertensive medication but not in non-dippers using antihypertensive medication. In contrast, the relative hazard for mortality increased in non-dippers and inverted dippers. These results suggest a cause-and-effect relationship for both dippers and non-dippers. CONCLUSION: The Ohasama study showed that the level and variability of hypertension as assessed by ABP and HBP are independent predictors of cardiovascular mortality. It also demonstrated an independent association between the prognosis of hypertension and each component of ABP and HBP, indicating the prognostic significance of these blood pressure measurements.

Bias↗

PubMed2001

Nonsense-mediated decay of mutant waxy mRNA in rice.

Two rice (Oryza sativa) waxy mutations of the Japonica background were shown to contain approximately 20% of the fully spliced mRNA relative to the wild type. Sequencing analysis of the entire waxy genes of the two mutants revealed the presence of premature translation termination codons in exon 2 and exon 7. These results indicated that the lower accumulation of fully spliced RNA in the mutants was caused by nonsense-mediated decay (NMD), which is an RNA surveillance system universally found in eukaryotes. It is interesting that levels of RNA retaining intron 1 were not changed by premature nonsense codons, suggesting that splicing may be linked with NMD in plants, as previously found in mammalian cells. Measurements of the half-lives of waxy RNAs in transfected rice protoplasts indicated that the half-life of waxy RNA with a premature nonsense codon was 3.3 times shorter than that without a premature nonsense codon. Because the wild-type waxy transcripts, which are derived from the Wx(b) gene predominantly distributed among Japonica rice, have been shown to be less efficiently spliced and their alternative splicing has been documented, we examined whether these splicing properties influenced the efficiency of NMD. However, no effects were observed. These results established that NMD occurs in rice waxy RNA containing a premature nonsense codon.

Alternative Splicing↗

PubMed2001

Complete 3-D reconstruction of dental cast shape using perceptual grouping.

To achieve the complete three-dimensional (3-D) data retrieval of the shape of dentition, dental casts were measured from four directions; occlusal, right, left, and labial sides using a line laser scanner. Reconstruction of the entire shape, including undercuts and tooth crowding area, was attempted by applying a perceptual grouping algorithm, which is one of pattern-recognition theories. In the data measured from occlusal, right and left sides, the rows of measurements were parallel to the frontal plane, and three-directionally combined data (3-DC data) was accomplished by affine transformation. While, in the labial side, transformation to the frontal plane was done since rows of the measured data were parallel to the sagittal plane. To combine the labial data with the 3-DC data and reconstruct the complete image, rearrangement of the order of the data in the file was attempted by applying the perceptual grouping. That is, the minimum total length of data combining was examined by considering the factor of proximity and continuity between the data. The most appropriate order of data combining and recognition of islands were accomplished. Using a computer graphic (CG) with a wire-frame model, complicated regions such as anterior segments showing tooth crowding and undercut area were found to be successfully reconstructed without any data defects. The accuracy of reconstruction was ascertained by comparing the characteristic distances between apexes of molars in the reconstructed model with the real cast. The difference was within 0.3 mm, and present method for dental cast reconstruction is considered to be satisfactory for the present purpose such as orthodontics.

Dental Casting Technique↗

PubMed2001

Seroprevalence of antibodies against spotted fever group rickettsia among dogs and humans in Okinawa, Japan.

We evaluated serum antibodies against Rickettsia japonica in 517 dogs (430 stray dogs and 87 pet dogs) and 164 humans in Okinawa, Japan, by indirect immunofluorescence assay. The seropositive rate in stray dogs was significantly higher than that in pet dogs (30.7 versus 4.6%, P<0.01). This high prevalence rate is attributed to the understandably frequent environmental exposure of stray dogs to tick infestation. Human samples obtained from Okinawa and Sapporo also showed a significant difference in seropositive antibody percentages (45.1 and 12.0%, respectively, P<0.01). This result suggests that there has been pre-exposure to spotted fever group rickettsia in humans in Okinawa.

Animals↗

PubMed2001

First detection of Ehrlichia platys in dogs and ticks in Okinawa, Japan.

We investigated Ehrlichia platys infection of dogs and ticks in Okinawa, Japan. Using E. platys specific primers, E. platys and HE3-R, PCR-positive results were obtained with 32.0% (64/200) of blood samples of dogs and 3.8% (3/77) of ticks. The nucleotide sequences of the amplified DNA fragment from the dogs and the ticks infesting them were identical, and the sequence corresponded to that of the E. platys Gzh981 strain. We concluded that there is a cyclic maintenance of E. platys between dogs and ticks in Okinawa.

Animals↗

PubMed2001

(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays showed a lack of toxicity of ganciclovir (GCV), C.OXTs, and their derivatives, to TaY(OK) cells at 1 microM. Therefore we compared the antiviral potencies of these drugs at 1 microM by monitoring the viral loads produced during a 1-day period during the course of the drug treatment. Among the drugs tested, 3'-fluorocarbocyclic oxetanocin A (3'F-C.OXT-A) was the most effective for inhibiting the virus production, and at concentrations ranging from 0.5 microM to 10 microM, the inhibition of the viral production was dose-dependent. A comparison of the chemical structures of the derivatives with that of C.OXT-A, which is the parental molecule, suggested that the 3'-fluorine-modification might account for the higher anti-HHV-6 activity and lower cytotoxicity.

An infection of TaY cells, which originated from an adult T-cell leukemia, with an HHV-6B OK isolate resulted in a chronically infected culture, termed TaY(OK). Cell cloning analysis revealed that the TaY(OK) culture consisted of a mixture of cells permissive and refractory to the infection, and that the permissive cells were continuously produced from the refractory cell population. Since the chronically infected culture has been maintained for over 2 years without the addition of uninfected TaY cells, we used it for an evaluation of the antiviral potency of nucleoside analogs, especially carbocyclic oxetanocins (C.OXTs).

Adenine↗

PubMed2001

The antitumor mechanism of 1-(2-deoxy-2-fluoro-4-thio-beta-D-arabinofuranosyl)-cytosine: effects of its triphosphate on mammalian DNA polymerases.

The mechanism of action of the antitumor nucleoside analog 1-(2-deoxy-2-fluoro-4-thio-beta-D-arabinofuranosyl)cytosine (4'-thio-FAC) was investigated. 4'-Thio-FAC inhibited cellular DNA synthesis, but not RNA and protein syntheses. We observed potent inhibitory action of the triphosphate of 4'-thio-FAC (4'-thio-FACTP) against DNA polymerase alpha, whereas it showed moderate inhibition of DNA polymerase beta and little inhibition of DNA polymerase gamma. The kinetic analysis showed that the inhibition mode of 4'-thio-FACTP towards DNA polymerase alpha was mixed type, implying a chain-terminating effect of 4'-thio-FACTP. The triphosphate of 2'-deoxy-2',2'-difluorocytidine (gemcitabine), a known antitumor nucleoside, did not show potent inhibition of these three DNA polymerases. Thus, the effect of the diphosphate of gemcitabine on ribonucleotide reductase was suggested to be more important for the antitumor action of gemcitabine. From these findings, the main target enzymes of 4'-thio-FAC and gemcitabine appear to be different. We found a synergistic effect of the two drugs in an in vitro model, which supports the above idea.

Antineoplastic Agents↗

PubMed2001