Biomedical subjects

H Shibata

Publications and source records attributed to H Shibata.

At least 91 records · Page 5Linked to original sources

PubMed2000

Synchronized transcriptional gene expression of H+-ATP synthase subunits in different tissues of Fischer 344 rats of different ages.

Little is known about the relationship between the stoichiometry of polypeptides of multisubunit enzyme complexes and the absolute amount of each transcript of the complexes in mammalian tissues. Here we showed that the absolute amounts of the transcripts of most subunits of rat H+-ATP synthase examined greatly differed in the different tissues, showing the following hierarchy of tissue-specificity: heart > kidney > brain approximately liver. However, surprisingly, there was no difference in the expression pattern of these in terms of the molar ratio of each transcript, indicating a nearly similar stoichiometric expression pattern irrespective of tissue or age of the rat. Therefore, the present finding clearly indicates that most of the transcripts of the 16 subunits of rat H+-ATP synthase were concertedly and synchronously expressed, having a constant expression pattern of the transcripts, irrespective of tissue or age of the rats. This is the first report of the absolute amounts of the transcripts of this multisubunit enzyme.

Age Factors↗

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

Peripheral blood extrathymic CD4(+)CD8(+) T cells with high cytotoxic activity are from the same lineage as CD4(+)CD8(-) T cells in cynomolgus monkeys.

We have previously reported that CD4/CD8 double-positive (DP) T cells with the resting memory phenotype are present in the periphery of healthy cynomolgus monkeys. In the present study, we performed functional studies on the T cells. The expression of CD4 and CD8 on DP, CD4 single-positive (SP) or CD8 SP T cells was stable in cultures with either mitogen or anti-CD3 antibody stimulation. In spite of lacking CD28 expression, DP T cells showed similar proliferative ability and apoptosis sensitivity to CD4 SP and CD8 SP T cells. DP T cells showed both helper and cytotoxic activities. Although the helper activity of DP T cells was lower than that of CD4 SP T cells, cytotoxic activity was comparable to that of CD8 SP T cells. Fresh DP T cells killed target cells mainly by the perforin-granzyme pathway. In addition, fresh DP T cells expressed a high level of mRNA for IFN-gamma and produced a high level of IFN-gamma when they were activated by anti-CD3 antibody ligation. On the other hand, several expanded DP T cell clones shared TCR V(beta) with expanded CD4 SP T cell clones, strongly suggesting that those two corresponding clones with DP and CD4 SP phenotypes might be derived from the same ancestor T cell. These results showed that the DP T cells are a novel T cell subset with functions overlapping with those of CD4 SP and CD8 SP T cells, and that they might play protective and regulatory roles in secondary immune response in cynomolgus monkeys.

Animals↗

PubMed2000

Determinants for the development of hypertension in adolescents. A 6-year follow-up.

OBJECTIVE: This study was aimed to evaluate the determinants of elevated blood pressure (BP) in adolescents. DESIGN AND METHODS: We retrospectively evaluated the BP and anthropometric data in 419 Japanese students (268 males and 151 females) during high school and university. Their annual health records were analysed for BP, heart rate, height and body weight between the ages of 15 and 21 years. RESULTS: The number of hypertensive students did not vary significantly during the 6 years. Concerning changes in BP categories according to the modified JNCVI classification between the ages of 15 to 21 years, 150 males kept a normal BP (keeping normal BP group); 39 males developed high BP (developing high BP group); 37 males kept high BP (keeping high BP group); and 42 males became normal BP (becoming normal BP group). The majority of females (n = 144, 95.4%) were included in the keeping normal BP group. In male students, both the keeping and becoming normal BP groups, especially the latter, showed a significant decrease in heart rate over the 6 years, while the other two groups showed no change. The height and body weight of each of the four groups showed a significant increase, but the body mass index (BMI) of the males in the becoming normal BP group did not increase over the 6 years. Body weight and BMI at the age of 15 years in the male keeping normal BP group were significantly below that of the other three groups; this difference persisted at the age of 21 years. Furthermore, male university students who showed a BP above 'high-normal' at the age of 21 years exhibited a significantly higher BP, heart rate, body weight and BMI than did the normotensives, when they were high school students. Stepwise regression analysis of the data showed that the best predictors of BP at the age of 21 years were the initial high school BP and BMI levels and changes in BMI and heart rate during the 6-year period for male students. CONCLUSION: Results indicate that the BP and BMI during high school and the changes in BMI and heart rate from high school to university influenced the BP at the age of 21 years in male students. Data indicate that information on the prevention and management of hypertension including weight control should begin early, especially in male adolescents.

Adolescent↗

PubMed2000

Predictors for functional decline among nondisabled older Japanese living in a community during a 3-year follow-up.

OBJECTIVES: To examine predictors for functional decline in basic activities of daily living (BADL) as well as predictors for decline in instrumental activities of daily living (IADL) among nondisabled older Japanese people living in a community during a 3-year interval from 1992 to 1995. DESIGN: A prospective cohort study. SETTING: A community-based environment. PARTICIPANTS: A total of 583 men and women aged 65 to 89 at baseline who were independent in both BADL and IADL. MEASUREMENTS: Independent variables regarding various factors potentially associated with functional decline were obtained from an interview survey and medical examinations at baseline. Dependent variables were functional status in BADL and IADL obtained at the time of the 3-year follow-up. RESULTS: During the 3-year follow-up, significant predictors for functional decline in BADL and only IADL decline included (1) age of > or = 75, (2) less hand-grip strength, and (3) a history of hospitalization during the past 1 year. In addition, having poor intellectual activities and having poor social roles were identified as significant predictors for functional decline in only IADL during the 3-year follow-up. Furthermore, not having the habit of taking a walk was identified as a significant predictor of functional decline in BADL during the 3-year interval. CONCLUSION: Having a high level hand-grip strength, good intellectual activities, and good social roles are strongly associated with remaining independence in IADL for the nondisabled Japanese persons aged > or = 65.

Activities of Daily Living↗

PubMed2000

[Evaluation of antiretroviral chemotherapy based on the profile of virus isolation from HIV-1 infected individuals].

It is well-known that the biological characteristics of HIV-1 persistently infected in the host have often changed into a rapid growth in vitro, T-cell line tropism and marked syncytium inducing (SI) ability accompanied by the progress of clinical stages from AC to ARC or AIDS. We have developed a follow-up diagnostic test using the clinical markers based on the virus phenotypes mentioned above, and reported that the test was significantly useful for determining the clinical status of HIV infected individuals. Recently, highly active antiretroviral therapy (HAART) was introduced into HIV-1 chemotherapy, and has been reported to be a markedly effective treatment for HIV infected individuals. In this study, we carried out an investigation to see whether the follow-up diagnosis was useful even after introducing the HAART in Japan in 1997. The results by the laboratory diagnosis on 139 HIV infected individuals who were clinically observed over a long period showed that the positive rate of virus isolation and MT-4 cell tropism in the isolates during the two years between 1997 and 1998 were significantly lower than that of the nine years from 1988 to 1996 before the implementation of HAART. In addition, we obtained data that the effect of HAART reflects the biological profiles of virus isolation more than the CD4+ T cell counts. These results suggest that data of clinical examination using virus isolation as a parameter are useful not only for predicting the development of AIDS but also for evaluating the effects of HAART, particularly in patients showing no association between the CD4+ T cell counts and the plasma viral load.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Gastric carcinoid tumours and pernicious anemia: case report and review of the literature.

Patients with pernicious anemia are at risk of developing carcinoid tumours of the stomach. A patient with pernicious anemia and multifocal carcinoid tumours of the gastric fundus that regressed after antrectomy is presented. The frequent occurrence of gastric carcinoid tumours in patients with long-standing pernicious anemia suggests that surveillance gastroscopy and biopsies of the fundus might be indicated. Compete functional antrectomy may effectively cause these tumours to regress by removing their excessive gastrin hormonal stimulation. However, incomplete antrectomy can result in persistently elevated serum gastrin and failure of total disappearance of the carcinoid tumours.

Anemia, Pernicious↗

PubMed2000

Lysophosphatidylcholine induces urokinase-type plasminogen activator and its receptor in human macrophages partly through redox-sensitive pathway.

Urokinase-type plasminogen activator (uPA) and its cell surface receptor (uPAR) have been shown to be expressed in macrophages in atherosclerotic arterial walls, but the regulatory mechanisms of their expression remain unclear. The present study was performed to examine the effects of lysophosphatidylcholine (lysoPC), an important atherogenic lipid, on the expression of uPA and uPAR in human monocyte-derived macrophages. LysoPC upregulated the mRNA expression of uPA and uPAR, and it increased the protein expression of uPA in the culture medium and bound to the cell surface and of uPAR in the particulate fraction of the cells. LysoPC significantly increased the binding of the amino-terminal fragment of uPA to the treated cells and the cell-associated plasminogen activator activity. LysoPC stimulated superoxide anion production and increased intracellular oxidant levels in the cells. The combined incubation with reduced glutathione diethyl ester or N-acetylcysteine, antioxidants, suppressed the upregulation of uPA and uPAR mRNA and the increase in plasminogen activator activity by lysoPC. uPA and uPAR mRNA expression was also induced by the incubation with xanthine and xanthine oxidase, a superoxide anion-generating system. The results suggest that lysoPC increased the expression of uPA and uPAR and their functional activities in human monocyte-derived macrophages, at least in part through a redox-sensitive mechanism. This coordinate increase in the expression of uPA and uPAR in human macrophages by lysoPC could play an important role in plaque formation and disruption, arterial remodeling, and angiogenesis in atherosclerotic arterial walls.

Acetylcysteine↗

PubMed2000

Oxidation and reduction of nitrite ion in the TiO2 photo-induced catalytic reaction.

During a photo-induced catalytic reaction under near UV irradiation to an aqueous suspension of Ti4O2, about 95% of NO2- was oxidized to NO3-, but NH4+ was not detected. The oxidation was inhibited by the addition of mannitol or under anaerobic conditions. The nitration of HPA was observed in the presence of t-buthanol, suggesting the formation of ONOO. An ESR spectrum gave a triplet signal at g = 2.041,in the presence of NO2-, mannitol, FeSO4, and MGD, indicating the reduction of NO2- to NO.

Catalysis↗

PubMed2000

Participation in school sports clubs and related effects on cardiovascular risk factors in young males.

The effects of belonging to sports clubs on male high school students was evaluated. The relationships between the type and extent of school-based exercise were examined in conjunction with percent body fat, blood pressure (BP), and other key metabolic parameters. A total of 264 male Japanese high school students (age range: 17-18 years old) were studied. Percent body fat was measured and blood was collected in the fasting state during a routine health check. Subjects were divided into two groups. The exercise (E) group (n=150) included students who had belonged to a sports club during the past 2 years. The non-exercise (NE) group (n=114) included students who did not belong to a sports club during the past 2 years. The body mass index was significantly greater in group E (21.7 +/- 2.3 (SD) kg/m2) than in group NE (20.7 +/- 2.6 kg/m2, p < 0.01). However, the percent body fat in group E (13.6 +/- 3.4%) was significantly lower than that in group NE (14.9 +/- 3.8%, p < 0.01). The diastolic BP and heart rate in group E (64 +/- 7 mmHg, 70 +/- 11/min) were significantly lower in group E than in group NE (66 +/- 8 mmHg, p < 0.05; 76 +/- 14/min, p < 0.01). The serum triglyceride level was significantly lower, and the HDL cholesterol level was higher in group E than in group NE. The homeostasis model assessment (HOMA) index, used as an index of insulin resistance, was similar in the two groups. However, the level of the HOMA index was significantly lower among the 62 subjects in group E who preferred highly dynamic exercise (1.50 +/- 0.46) than it was among those in group NE (1.66 +/- 0.49, p < 0.05). Results indicate that belonging to sports clubs influences the BP and lipid profiles of adolescent males, as well as their percent body fat. In view of the reduction of cardiovascular risk factors, it is recommended that even young males practice regular exercise, especially aerobic exercise.

Adolescent↗

PubMed2000

Plasma aldosterone concentrations are not related to the degree of angiotensin-converting enzyme inhibition in essential hypertensive patients.

There is increasing evidence of important cardiovascular effects of aldosterone via classical mineralocorticoid receptors in the heart. Aldosterone plus excess salt administration has been shown to produce both cardiac hypertrophy and cardiac fibrosis in rats. Various clinical studies have reported that aldosterone plays an important role in cardiac hypertrophy; however, the factors that control plasma aldosterone concentrations during angiotensin-converting enzyme (ACE) inhibitor treatment have still not been established. In the present study, we examined the relationship between plasma aldosterone concentrations and the degree of ACE inhibition in 25 essential hypertensive patients treated with an ACE inhibitor. Blood pressure decreased with treatment and plasma ACE activity, estimated in vitro (by a colorimetric method) and in vivo (by plasma angiotensin II/angiotensin I ratio) assay, was suppressed compared with that of hypertensive patients treated with medication other than ACE inhibitors. No relationship was found between the level of ACE inhibition and plasma aldosterone concentrations, which rose in parallel with the duration of ACE inhibitor treatment. The present study demonstrates that continuous ACE inhibitor therapy produces significant suppression of plasma ACE activity in essential hypertensive patients, but that no relationship exists between plasma aldosterone concentrations and levels of ACE inhibition. Plasma aldosterone concentrations tend to increase with the duration of ACE inhibitor treatment, although this increase did not reflect a reduced inhibition of ACE activity.

Aldosterone↗

PubMed2000

Prognostic value of nighttime blood pressure in the elderly: a prospective study of 24-hour blood pressure.

Although it has been suggested in several reports that 24-h ambulatory blood pressure (BP) is a better predictor than casual BP measured in a clinician's office of the incidence of cardiovascular (CV) events, little information is available concerning the prognostic value of nighttime BP in the elderly population. Therefore, to evaluate the clinical implications of the nighttime BP in the elderly, we prospectively followed-up 324 elderly individuals (mean age, 77.2 +/- 7.0 years) who had undergone ambulatory BP monitoring at an annual health examination over a mean follow-up period of 51.5 +/- 22.0 months, and the relationship between BP and CV events was analyzed using Cox's proportional hazard model. For the analysis, 310 participants, excluding 14 subjects who were withdrawn due to non-CV events, were classed into two groups, one consisting of 134 individuals who were undergoing treatment with an anti-hypertensive drug (medicated group) and another consisting of 176 who were not medicated (nonmedicated group). New cardiovascular events developed in 43 cases in the medicated group and in 14 cases in the non-medicated group during the follow-up period. In the medicated group, a linear relationship was observed between BP and the event rates. The hazard ratio for CV events adjusted for age, sex, and other cardiovascular risks was 1.28 (95% confidence interval [CI], 1.05 to 1.54, p< 0.05) for a 10 mmHg increase of 24-h systolic BP. Corresponding values in 24-h diastolic BP, nighttime systolic BP, and nighttime diastolic BP were 1.71 (1.19 to 2.46, p< 0.01), 1.34 (1.13 to 1.58, p< 0.01), and 1.67 (1.20 to 2.31, p< 0.01), respectively. In the non-medicated group, the event rate was least in the subgroup in the second-lowest quartile for nighttime systolic BP, with a slight non-significant increase in the subgroup of the lowest quartile. It was shown that insufficient control of nighttime BP in the elderly with hypertension is associated with the development of CV complications.

Aged↗

PubMed2000

The ortholog of human ataxin-2 is essential for early embryonic patterning in C. elegans.

Ataxin-2, the gene product of the human spinocerebellar ataxia type 2 (SCA2) gene, is a protein of unknown function. Ataxin-2 interacts with ataxin-2-binding-protein 1 (A2BP1), a member of a novel family of putative RNA-binding proteins. Because the sequences of ataxin-2 and A2BP1 are evolutionarily conserved, we investigated functional aspects and expression pattern in the nematode Caenorhabditis elegans. Human ataxin-2 has 20.1% amino acid identity and 43.9% similarity to its C. elegans ortholog, designated ATX-2, that encodes a predicted 1026 aa protein. One of the worm orthologs of human A2BP1 is the numerator element FOX-1, with an overall 29.8% aa identity. We studied the expression pattern of atx-2 using the endogenous promotor coupled with a GFP expression vector. Atx-2 was widely expressed in the adult worm with strong expression in muscle and nervous tissue. It was also heavily expressed in the embryo. In order to elucidate the function of atx-2 and fox-1, we conducted RNA interference (RNAi) studies. The interfering dsRNA was introduced into larval L4 stage worms of the N2 strain by microinjection or soaking. DsRNA representing the full-length atx-2 gene resulted in arrested embryonic development in the offspring of all 58 microinjected worms. Nomarski imaging showed embryos in different stages of developmental arrest, indicating an essential role of atx-2 for early embryonic development. When fox-1 was targeted by RNAi, there was a marked reduction in the number of eggs per worm. The results presented here underline previous findings about the interaction of human ataxin-2 and A2BP1.

Animals↗

PubMed2000

In vitro proliferation potential of AC133 positive cells in peripheral blood.

AC133 antigen is a novel marker for human hematopoietic stem/progenitor cells. In this study, we examined the expression and proliferation potential of AC133(+) cells obtained from steady-state peripheral blood (PB). The proportion of AC133(+) cells in the CD34(+) subpopulation of steady-state PB was significantly lower than that of cord blood (CB), although that of cytokine-mobilized PB was higher than that of CB. The proliferation potential of AC133(+)CD34(+) and AC133(-)CD34(+) cells was examined by colony-forming analysis and analysis of long-term culture-initiating cells (LTC-IC). Although the total number of colony-forming cells was essentially the same in the AC133(+)CD34(+) fraction as in the AC133(-)CD34(+) fraction, the proportion of LTC-IC was much higher in the AC133(+)CD34(+) fraction. Virtually no LTC-IC were detected in the AC133(-)CD34(+) fraction. In addition, the features of the colonies grown from these two fractions were quite different. Approximately 70% of the colonies derived from the AC133(+)CD34(+) fraction were granulocyte-macrophage colonies, whereas more than 90% of the colonies derived from the AC133(-)CD34(+) fraction were erythroid colonies. Furthermore, an ex vivo expansion study observed expansion of colony-forming cells only in the AC133(+)CD34(+) population, and not in the AC133(-)CD34(+) population. These findings suggest that to isolate primitive hematopoietic cells from steady-state PB, selection by AC133 expression is better than selection by CD34 expression.

AC133 Antigen↗

PubMed2000

Effects of functional decline on quality of life among the Japanese elderly.

The effects of functional decline upon social networks, life satisfaction, and depression were observed and statistically tested in a longitudinal prospective design. Subjects were 692 Japanese elderly, aged sixty-five years or older, with high functional capacity at baseline. During a two-year period of follow-up, 12.3 percent of the subjects experienced functional decline. Repeated-measure analyses of covariance with statistical tests for simple main effects revealed that changes in the criterion variables significantly differed along with changes in functional health status when the effects of age, gender, and socioeconomic status were controlled. The subjects who experienced functional decline showed a larger decrease in the number of relatives, friends, and neighbors having frequent contacts, a larger decline in life satisfaction, and a larger increase in depression than those without functional decline. The results seem to confirm further the importance of functional health status as a prerequisite for higher quality of life in old age.

Activities of Daily Living↗

PubMed2000

Risk factors associated with persistent postoperative hypertension in Cushing's syndrome.

The aim of the present study was to assess the long-term results of adrenalectomy and to evaluate potential risk factors for the persistence or recurrence of hypertension. Forty-five patients with Cushing's syndrome caused by benign cortisol-producing adrenocortical adenomas were evaluated before and for a period of 1 year after surgical cure. When the patients were classified into two groups according to whether their preoperative BP was more (HBP group) or less (NBP group) than 140/90 mmHg, the BP level was found to be continuously higher in the HBP group than in the NBP group during the year after surgery. This finding suggests that the preoperative BP level in Cushing's syndrome may be a determinant factor for persistent hypertension after surgery (P<0.05). In addition, a correlation was found between postoperative BP level and duration of hypertension (P<0.05), but no relationships were found between postoperative BP levels and other factors, including age, BMI, tumor size, serum cortisol, aldosterone, potassium, total cholesterol, or glucose levels. The above findings indicate that intensive control of preoperative BP to maintain it below 140/90 mmHg with antihypertensive medication is a very important means of improving prognosis for postoperative BP. Immediate diagnosis and surgical treatment to reduce the duration of hypertension are also crucial for the long-term BP prognosis.

Adrenalectomy↗

PubMed2000

Expression and regulation of BCL-2 family genes in human adrenocortical adenomas in comparison with adrenal hyperplasia of Cushing's disease.

The significance of increases in the expression of apoptosis-suppressing genes such as bcl-2 and mcl-1/EAT in human adrenal tumors has not yet been fully elucidated. Furthermore the roles of these genes in cell proliferation may involve interaction with steroidogenesis in the tumors via intracellular second messengers. Cyclic AMP (cAMP) caused human adrenocortical H295R cells to overexpress hCYP17 resulting in hypersecretion of cortisol. At the same time, however, expression of bcl-2, which has a cAMP response element (CRE), was not affected. Furthermore, in vivo Bcl-2 protein analysis showed its down-regulation in adrenal hyperplasia of Cushing's disease despite ACTH stimulation. Exogenous addition of glucocorticoid did not affect the expression of bcl-2 family genes. Expressions of Mcl-1/EAT and Bax did not differ markedly among human adrenal glands affected by various pathologies. In conclusion the down-regulation of Bcl-2 in Cushing's disease did not agree with no induction of this gene by cAMP in H295R cells, suggesting that expression of Bcl-2 protein was not regulated mainly by cAMP-protein kinase (PKA) pathways in human adrenal hyperplasia.

Adenoma↗

PubMed2000

Transcriptional regulation of steroid receptor coactivator-1 (SRC-1) in glucocorticoid action.

Diverse mechanisms of steroid receptor action have been clarified in recent years, as a consequence of the discovery of multiple coactivators. Among them, steroid receptor coactivator-1 (SRC-1) is a member of the p160 coactivator families, which are 160 kDa proteins that interact with steroid receptors in a hormone-sensitive manner. Since coactivators function as transcriptional power boosters, subtle changes in coactivator expression levels in certain cells markedly change of receptor-mediated transcriptional activity. Expression of the glucocorticoid receptor (GR) has been shown to be autoregulated in glucocorticoid action, i.e., GR is downregulated by its cognate ligand, indicating that this autoregulation of GR may protect target cells against excessive hormone action. In the present study, we examined whether coactivator expression levels are also regulated by glucocorticoids. Among several coactivators, the SRC-1 mRNA level was downregulated by dexamethasone treatment in rat tissues, such as liver, heart, kidney, stomach, and cerebrum, in vivo. We also demonstrated dexamethasone-mediated downregulation of SRC-1 mRNA and its protein levels in rat renal mesangial cells in vitro. These results suggest that ligand-mediated downregulation of SRC-1 is crucial in the physiology of glucocorticoid action.

Animals↗