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Biomedical subjects

Yoko Suzuki

Publications and source records attributed to Yoko Suzuki.

18 recordsLinked to original sources
PubMed2005

Propagation of avalanches in Mn12-acetate: magnetic deflagration.

Local time-resolved measurements of fast reversal of the magnetization of single crystals of Mn12-acetate indicate that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity that is roughly 2 orders of magnitude smaller than the speed of sound. We argue that this phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance.

Journal Article↗
PubMed2005

Modeling the interplay between geometrical and energetic effects in protein folding.

A theoretical framework is constructed with the aid of a free-energy functional method that is capable of describing the interplay between geometrical and energetic effects on protein folding. In this paper, we generalize a free-energy functional model based on polymer theory to make it more appropriate for comparison with protein folding simulations and experiments. This generalization is made by introducing cooperativity into the configurational entropy and the internal energy. Modifications to configurational entropy enable the model to account for the loop-loop interactions, a contribution neglected in the original model. Modifications to the internal energy introduce many-body corrections, which are needed to establish quantitative contact to simulations as well as experimental observations. To demonstrate the efficiency of the modified analytical model, we compare our results with C(alpha) structure-based (Go) model simulations of chymotrypsin inhibitor II and the SH3 domain of src.

Entropy↗
PubMed2005

An increase of oxidized coenzyme Q-10 occurs in the plasma of sporadic ALS patients.

We have compared plasma redox status of coenzyme Q-10 in 20 sporadic amyotrophic lateral sclerosis (sALS) patients with those in 20 healthy age/sex-matched controls. A significant increase in the oxidized form of coenzyme Q-10 (sALS=109.3+/-95.2 nM; controls=23.3+/-7.5 nM, P=0.0002) and in the ratio of oxidized form of coenzyme Q-10 to total coenzyme Q-10 (%CoQ-10) (sALS=12.0+/-9.3%; controls=3.2+/-0.9%, P<0.0001) were observed. Moreover, %CoQ-10 correlated significantly with the duration of illness (rho=0.494, P=0.0315). Our finding suggests systemic oxidative stress in the pathogenesis of sALS.

Adult↗
PubMed2005

Obesity and risk of cancer in Japan.

We conducted a population-based prospective cohort study in Japan to examine the relationship between body mass index (BMI) and the risk of incidence of any cancer and of cancer at individual sites. Body mass index was calculated from self-administered body weight and height at baseline. Relative risks (RR) and 95% confidence intervals (CI) were calculated in multivariate proportional-hazards models. Among 27,539 persons (15,054 women and 12,485 men) aged 40 years or older who were free of cancer at enrollment in 1984, 1,672 (668 women and 1,004 men) developed cancer during 9 years of follow-up. In women, after adjustment for potential confounders, the RR of all cancers associated with different BMI, relative to a BMI of 18.5-24.9, were 1.04 (95% CI = 0.85-1.27) for BMI = 25.0-27.4, 1.29 (1.00-1.68) for BMI = 27.5-29.9 and 1.47 (1.06-2.05) for BMI >/=30.0 (p for trend = 0.007). Higher BMI was also significantly associated with higher risk of cancers of the colorectum, breast (postmenopausal), endometrium and gallbladder in women. In men, we observed significantly increased all-cancer risk among only never-smokers. Overweight and obesity could account for 4.5% (all subjects) or 6.2% (never-smokers) of the risk of any cancer in women and -0.2% (all subjects) or 3.7% (never-smokers) in men. The value for women was within the range among women reported from Western populations (3.2%-8.8%). Our data demonstrate that excess weight is a major cancer risk among Japanese women.

Adult↗
PubMed2005

Identification of nitrated proteins in the normal rat brain using a proteomics approach.

BACKGROUND: The nitration of tyrosine has been suggested to play a role in the pathogenesis of neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and Alzheimer's disease (AD). METHODS: In the present study, we identified four targets of protein nitration, T-complex polypeptide 1 alpha subunit (TCP-1), neurofilament L (NFL), glial fibrillary acidic protein (GFAP) and clathrin heavy chain (CHC), in the normal rat cortex using a proteomics approach. CONCLUSIONS: There have been no reports on these proteins being identified by proteomics as nitrated forms in the brain. For further study, we have to investigate alterations in these nitrated proteins during aging and in neurodegenerative disorders.

Amino Acid Sequence↗
PubMed2005

Green tea and the risk of colorectal cancer: pooled analysis of two prospective studies in Japan.

BACKGROUND: Although laboratory experiments suggest protective effects of green tea against colorectal cancer, few prospective cohort studies have been conducted. METHODS: We conducted a pooled analysis of two prospective cohort studies among residents in Miyagi Prefecture in rural northern Japan. The first study started in 1984 and included 26,311 subjects. The second study started in 1990 and included 39,604 subjects. The subjects responded to a self-administered questionnaire including an item on green tea consumption. With 7 to 9 years of follow-up, 305 colon and 211 rectal cancers were identified in the two cohorts through record linkage to a regional cancer registry. We used Cox regression to estimate the hazard ratio (HR) of colorectal cancer according to the consumption of green tea with adjustment for potential confounders, and pooled the estimates obtained from each cohort by general variance-based method. RESULTS: Multivariate pooled HRs for colon cancer associated with drinking 1-2, 3-4, and 5 or more cups of green tea per day, as compared with less than 1 cup per day, were 1.06 (95% confidence interval [CI]=0.74-1.52), 1.10 (0.78-1.55), 0.97 (0.70-1.35), respectively (trend p=0.81). Corresponding HRs for rectal cancer were 0.85 (95% CI=0.56-1.29), 0.70 (0.45-1.08), 0.85 (0.58-1.23), respectively (trend p=0.31). CONCLUSIONS: Consumption of green tea was not associated with lower risk of colorectal cancer.

Adult↗
PubMed2004

Redox status of plasma coenzyme Q10 indicates elevated systemic oxidative stress in Parkinson's disease.

Oxidative stress is suggested to play an important role in the pathogenesis of Parkinson's disease (PD). However, no elevation of plasma oxidative stress marker has been reported. We measured percent content of the oxidized form of coenzyme Q10 in total coenzyme Q10 (%CoQ-10) because %CoQ-10 has been shown to be a sensitive marker of oxidative stress. A slight but significant elevation in %CoQ-10 was observed in PD patients when compared with age/gender-matched normal subjects, suggesting elevated systemic oxidative stress in PD patients.

Adult↗
PubMed2004

Body mass index and mortality in Japan: the Miyagi Cohort Study.

BACKGROUND: The relation between body mass index (BMI) and mortality is not well established. The objective of this study was to examine the association in Japanese adults. METHODS: In 1990, 18,740 men and 20,870 women in Miyagi Prefecture in rural northern Japan (40-64 years of age) completed a self-administered questionnaire including height and weight. Cox regression was used to estimate relative risk (RR) of mortality according to levels of BMI, with adjustment for age, marital status, smoking, drinking, walking, and weight change since 20 years of age. RESULTS: During 11 years of follow-up, 1,121 men and 567 women had died. Compared with the referent BMI category (23.0-24.9), women in the highest BMI category (BMI>30.0) had a RR of death of 1.64 (95% confidence interval (CI), 1.09-2.49) and men and women in the lowest BMI categories (BM1<18.5) had a RR of death of 2.06 (95% CI, 1.49-2.84) and 1.83 (95% CI, 1.17-2.88), respectively, after adjustment for potential confounders and after exclusion of deaths occurring in the first three years of follow-up. We did not observe significant differences in mortality for subjects with wide range of BMI (18.5 or higher in men and 18.5 to 29.9 in women). CONCLUSIONS: The risk of death from all causes increases in lean men and women, and obese women in this cohort.

Adult↗
PubMed2004

Health practices and mortality in Japan: combined effects of smoking, drinking, walking and body mass index in the Miyagi Cohort Study.

BACKGROUND: Evidence is limited regarding the association between the combinations of multiple health practices and mortality. METHODS: In 1990, 28,333 men and women in Miyagi Prefecture in rural northern Japan (40-64 year of age) completed a self-administered questionnaire. A lifestyle score was calculated by adding the number of high-risk practices (smoking, consuming > or = 22.8 g alcohol/d, walking < 1 hr/d, body mass index < 18.5 or > or = 30.0). Cox regression was used to estimate relative risk (RR) of mortality according to the lifestyle score, with adjustment for age, education, marital status, past history of diseases, and dietary variables. During 11 years of follow-up, 1,200 subjects had died. RESULTS: We observed linear increase in risk of death associated with increasing number of high-risk practices: compared with men who had no high-risk practices, multivariate RRs for men who had 1 to 4 practices were 1.20, 1.66, 1.94, and 3.96, respectively (P for trend<0.001), and corresponding RRs for women were 1.31, 2.14, 3.98, 5.56, respectively (P for trend<0.001). A unit increase in the number of high-risk practices corresponded to being 2.8 and 4.8 years older for men and women, respectively. CONCLUSIONS: In this prospective cohort study of middle-aged men and women in rural Japan, a larger number of high-risk practices was associated with linear increase in risk of all-cause mortality.

Adult↗
PubMed2003

Antioxidant properties of carvedilol: inhibition of lipid peroxidation, protein oxidation and superoxide generation.

Oxidative stress has been suggested to be an etiological factor in cerebro- and cardiovascular disorders. We examined antioxidant activities of carvedilol, a beta- and alpha-adrenoreceptor blocker. Carvedilol suppressed lipid auto-oxidation and protein carbonyl formation in brain homogenate in a dose-dependent manner. Carvedilol also suppressed superoxide generation of human neutrophils. These properties of carvedilol should be suitable for treating hypertension resulting in cerebro- and cardiovascular diseases.

Animals↗
PubMed2003

[A case of Tinea capitis caused by Trichophyton tonsurans].

A 10-year-old Peruvian girl, living in Japan since 1996, visited our hospital in August 2000 complaining of alopecia which had been present on her scalp for one year. The bald areas appeared as multiple small, scattered, angular patches with indistinct margins. Follicular pustules, erythemic nodules and lymphadenopathy were also seen. In the culture of the affected hair, a tan surface with wiry undulations grew on Sabouraud's media. The colony reverse had reddish-brown central pigmentation. Slide cultured fungi produced great numbers of round and short club-shaped microconidia, hyphae and intercalary chlamydospores. These fungi showed the following characteristics: positive urease test, no pigment production on cornmeal agar and positive thiamine dependency. The restriction fragment length polymorphism pattern and the nucleotide sequences of ribosomal-DNA internal transcribed spacer region of the causative fungus was compatible with Trichophyton tonsurans. Daily administration of 125 mg of terbinafine resulted in a satisfactory response and the lesion healed almost completely.

Administration, Oral↗
PubMed2003

[A case suspected multibacillary leprosy].

The presence of acid-fast bacilli in the lesion and its positive culture usually provide the diagnosis in cutaneous mycobacteriosis. But in diagnosis of leprosy, characteristic clinico-histopathological findings are so important as the demonstration of the organism, because of the failure to grow Mycobacterium leprae in vitro. It is classified in various forms along a spectrum of infectious and immunological symptoms supported by the pathogen-host relationship. The patient was a Japanese woman 69 years of age. She had been diagnosed as multibacillary leprosy with the positive results of slit-smear tests and the confirmation of the genomic sequence by PCR. Multidrug therapy had been started, but it was discontinued afterwards because an exact diagnosis of leprosy could not be determined by clinical, histological, and immunological assessment. As its diminishing prevalence in Japan, where ordinary physicians cannot have opportunities to see leprosy patients and they are unfamiliar with protean manifestations of the disease, it can be very difficult to make accurate diagnosis in those cases with atypical findings.

Aged↗
PubMed2002

Antioxidant properties of cabergoline: inhibition of brain auto-oxidation and superoxide anion production of microglial cells in rats.

We evaluated the effect of cabergoline on superoxide anion production by rat microglial cells using a 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1, 2-a]pyrazin-3-one-dependent chemiluminescence assay. Cabergoline dose-dependently inhibited superoxide anion production by microglial cells stimulated with phorbol myristate acetate or opsonized zymosan, while it had no superoxide dismutase-like activity. We also studied the effects of cabergoline and alpha-tocopherol on thiobarbituric acid reactive substances formation in homogenized brain-tissue in rats. Cabergoline was stronger than alpha-tocopherol in inhibiting auto-oxidation. While cabergoline is commonly used to treat the motor dysfunction of Parkinson's disease, it may also be effective in inhibiting oxidative stress, a possible mechanism of dopaminergic neuronal degeneration in Parkinson's disease.

Animals↗
PubMed2002

Chemically modified ribozyme targeting TNF-alpha mRNA regulates TNF-alpha and IL-6 synthesis in synovial fibroblasts of patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is chronic polyarthritis in which a variety of inflammatory cytokines play a role. Since tumor necrosis factor-alpha (TNF-alpha) is one of the most important cytokines in the pathogenesis of RA, we evaluated the feasibility of ribozymes as a therapeutic agent to control the inflammatory process of RA synovium. A hammerhead ribozyme against TNF-alpha was chemically modified to increase nuclease resistance and added to RA fibroblastlike cell cultures without using a delivery system. The cellular uptake of fluorescent-labeled ribozyme into synovial cells was found to last at least 48 hr by confocal laser scanning microscopy. The ribozyme targeting TNF-alpha gene inhibited both the expression of TNF-alpha mRNA and the secretion of TNF-alpha and IL-6. The cytotoxic effect by the ribozyme on synovial cells was negligible when determined by an alamar blue assay. Chemically modified ribozymes designed to suppress the TNF-alpha gene may be potential as a therapeutic agent for rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed2002

Elevation of serum thrombopoietin precedes thrombocytosis in acute infections.

To clarify the mechanisms underlying thrombocytosis secondary to infections, we longitudinally studied serum levels of thrombopoietin (TPO) and interleukin (IL)-6 in 15 infants and young children with prominent thrombocytosis (platelets >700 x 10(9)/l) following acute infections and 116 age-matched controls using an enzyme-linked immunosorbent assay. The subjects included nine patients with bacterial infections, three with viral infections and three with non-determined pathogens. TPO values in the controls were 2.24 +/- 0.87 fmol/ml (mean +/- SD) with a 95% reference interval of 0.85-4.47 fmol/ml. In the first week of infection, platelet counts were normal, but TPO values increased (approximately 10.73 fmol/ml). TPO levels peaked on day 4 +/- 2 at 6.44 +/- 2.37 fmol/ml and then fell gradually. When platelet counts peaked in the second and third weeks, TPO levels were similar to the controls. IL-6 levels in the first week rose and dropped more rapidly than TPO. Serum TPO values were significantly correlated with C-reactive protein levels (r = 0.688, P < 0.001) and IL-6 levels (r = 0.481, P = 0.027). These results suggest that TPO contributes to thrombocytosis following infections in conjunction with IL-6, arguing for additional regulatory mechanisms of blood TPO levels.

Acute Disease↗
PubMed2002

Trend of neonatal group B streptococcal infection during the last 15 years.

BACKGROUND: The survey was designed to determine the trend of group B streptococcal (GBS) infection during the last 15 years, as well as update the reality of this disease. METHODS: Questionnaires were administered every 5 years towards neonatal intensive care unit-equipped hospitals. The first survey was made from 1983 to 1987, the second one from 1988 to 1992 and the third one from 1993 to 1997. The 15-year questionnaire survey included a total of 831 patients. The changes in number of patients, the ages at onset, the diagnosis, the serotypes of causative agents, the presence or absence of complicated delivery and the prognosis were analyzed. RESULTS: It seems that the increasing trend of the number of patients has stopped in the period from 1993 to 1997 (third survey). The most common causative subtype was type III GBS, regardless of early onset type or late onset type. As to perinatal abnormality, approximately 40% of the early onset cases were free from risk factors. Concerning the prognosis, 22.6% of early onset cases and 38.7% of late onset cases died or had sequelae. CONCLUSIONS: The number of GBS-infected cases has stopped increasing, but it is still necessary to carry out screenings of pregnant women for the purpose of decreasing the onset of the disease.

Carrier State↗
PubMedDate not supplied

A structural model of the relationships among self-efficacy, psychological adjustment, and physical condition in Japanese advanced cancer patients.

We made detailed research for relationships among physical condition, self-efficacy and psychological adjustment of patients with advanced cancer in Japan. The sample consisted of 85 (42 males and 43 females) advanced cancer patients. Interviews were conducted with some measurement scales including the Self-efficacy scale for Advanced Cancer (SEAC), and the Hospital Anxiety and Depression Scale (HADS). Karnofsky Performance Status (KPS) and medication status were also recorded from the evaluation by physicians. We used structural equation modeling (SEM) for statistical analysis. The analysis revealed that the model, including three self-efficacy subscales, depression, anxiety, KPS, meal-, liquid-intake, prognosis and three latent variables: 'Self-efficacy', 'Emotional Distress', and 'Physical Condition,' fit the data (chi-square(24)=28.67, p=0.23; GFI=0.93; CFI=0.98; RMSEA=0.05). In this model, self-efficacy accounted for 71% of the variance in emotional distress and physical condition accounted for 8% of the variance in self-efficacy. Overall, our findings suggest clearly that close relationships existed among physical condition, self-efficacy and emotional distress. That is, patients in good physical condition had a high self-efficacy, and patients with high self-efficacy were less emotionally distressed. These results imply that psychological intervention which emphasizes self-efficacy would be effective for advanced cancer patients.

Adaptation, Psychological↗