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Biomedical subjects

H Toyoshima

Publications and source records attributed to H Toyoshima.

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

Difference in the occurrence of cardiovascular events according to class of antihypertensive agent, based on a follow-up study of Japanese hypertension patients.

We conducted a nested case-control study to evaluate the relationship between antihypertensive agent class and the incidence of initial cardiovascular events. A total of 7.443 patients being treated with an antihypertensive agent in 1985-1986 were enrolled for follow-up of up to 5 years. A total of 362 patients (186 males and 176 females) developed cardiovascular events. Age (5-year interval) and sex-matched controls were then randomly selected. A Multiple logistic regression analysis was done to control for the effects of confounding factors. The results showed that the use of diuretics and beta-blockers was associated with a reduced risk of cardiovascular events (odds ratio [OR] =0.65, 95% confidence interval [CI]: 0.49-0.86, and OR=0.75, 95% CI: 0.56-1.02, respectively), against a significantly raised risk associated with the use of calcium antagonists (OR=1.34, 95% CI: 1.03-1.80). However, as far as stroke was concerned, there was no significant association of risk with the use of any agent. The control group was found to be similar to the case group with respect to the changes in the treatment program during the follow-up period. The results suggest that the calcium antagonists used in Japan during the period of 1985-1990 constituted a potential risk for the occurrence of cardiovascular events.

Adrenergic beta-Antagonists↗
PubMed2001

[Epidemiology and primary prevention of colorectal cancer].

The incidence of and mortality from colorectal cancer are increasing in Japan, as is its proportion among all malignant neoplasms. Thus, primary prevention of this cancer is crucial. Colorectal cancer is caused by interactions between host and environmental factors, with accumulation of gene alterations, such as activation of oncogenes and inactivation of suppressor genes, and generally involves an adenoma-carcinoma sequence. Carcinogenesis progresses with multi-factor, multi-hit and multi-stage mechanisms. According to the report by WCRF/AICR, convincing preventive factors include eating vegetables (not fruit) and physical activity (colon only), while probable risk factors are red meat and alcohol. Possible preventive factors include dietary fiber, starch and carotenoids, whereas possible risk factors include high body mass, fat and heavily cooked meat. Such preventive and risk factors for colorectal cancer are discussed in this review.

Colorectal Neoplasms↗
PubMed2001

[Not Available].

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Possible involvement of the p57(Kip2) gene in bone metabolism.

We previously uncovered that growth stimulation of rat primary osteoblasts by transforming growth factor-beta1 (TGF-beta1) resulted in a dramatic decrease in p57(Kip2), a member of cyclin-dependent kinase (CDK) inhibitors, through the proteasomal degradation pathway (Urano et al., J. Biol. Chem. 274, 12197-12200, 1999). Here we demonstrated that the amount of p57 protein increases markedly, when rat calvarial primary osteoblasts treated with 1,25-dihydroxyvitamin D3 transit from proliferation toward differentiation. Next, we have analyzed the association of four amino acids deletion polymorphism of p57 and bone mineral density (BMD). The p57 genotype was determined in 154 postmenopausal Japanese women. When we separated the subjects into two groups, one having one or two copies of deletion polymorphism and the other without the deletion, the former subjects had higher BMD (Z score of total body, 0.67 +/- 0.93 vs 0. 23 +/- 0.90, mean +/- standard deviation; P = 0.021). Taken together, these findings suggest that the p57 regulated in the osteoblast proliferation and differentiation may play a role in determination of bone mineral density and pathogenesis of osteoporosis.

Aged↗
PubMed2000

Effect of vibration magnitude and repetitive exposure on finger blood flow in healthy subjects.

In order to study the effect of the magnitude of vibrations and repetitive exposure on finger blood flow, we exposed ten healthy subjects to three experimental conditions: (1) vibration of 3.16 m/s2 at 60 Hz, (2) vibration of 31.6 m/s2 at 60 Hz, and (3) no vibration, as a control. Under the experimental conditions, the right hand was exposed to 5-min vibration three times, with intervening 5-min rests. Meanwhile, the blood flows of both middle fingers were continuously measured with a blood flow meter based on the thermal diffusion method. Finger blood flow was significantly decreased in both hands with exposure to vibrations of 3.16 m/s2 and 31.6 m/s2. Increased magnitude of vibration tended to enhance the decrease in finger blood flow in both hands, and repeated exposure to vibration had cumulative effects on the decrease in finger blood flow in the unexposed left hand.

Adult↗
PubMed2000

Changes in serum hepatic fibrosis markers in biochemical responders to interferon therapy for chronic hepatitis C.

Serum hepatic fibrosis markers (7s domain of type IV collagen, N-terminal peptide of type III procollagen, and hyaluronate) were determined during and after a 6-month interferon treatment of patients with chronic hepatitis C. Changes in these markers were compared among the patients who showed a sustained normalization of serum alanine transaminase (ALT) levels with and without eradication of serum hepatitis C virus RNA (complete responders and biochemical responders) and nonresponders. In the case of complete responders, the serum 7s domain of type IV collagen and the N-terminal peptide of type III procollagen levels decreased at the end and 24 weeks after the end of the treatment. Hyaluronate levels were significantly decreased 24 weeks after the end of the treatment, as compared with those prior to the treatment. During and after interferon treatment, changes in these markers in the case of biochemical responders were nearly the same as those in the complete responders. These results suggest that serum hepatic fibrosis markers decrease in patients with chronic hepatitis C who show a sustained normalization of ALT after interferon treatment, even if serum hepatitis C virus RNA fails to be eradicated.

Journal Article↗
PubMed2000

Thermal and physicochemical properties of rice grain, flour and starch.

Three types of rices, namely, Thailand rice (Indica), Nipponbare (Japonica), and Himenomochi (Japonica waxy), in grain, flour, and starch forms have been studied for their thermal and physicochemical properties. In grain form, Indica was slender and Japonica rices were bold and thick. Indica had the highest protein and amylose equivalent. Protein contents in isolated starches varied from 0.2 to 0.9%. Cooked Indica grain was hardest and waxy rice was softest; stickiness was highest in Japonica rice. Glass transition temperature (T(g)) was highest in Indica rice flour (approximately 222 degrees C) and almost the same in Japonica rice flours. Melting point was highest for Japonica (approximately 264 degrees C) and almost the same for Japonica waxy and Indica rice flours. T(g) values of starches were almost the same in Indica and Japonica waxy (approximately 237 degrees C); defatting caused reduction in this property in all of the starches. Highest melting point was shown by Indica starch (approximately 276 degrees C) and was almost the same for the other two starches. Protein and fats play a critical role in glass transition and melting points of rice flours and their respective starches. Viscosities of the cooked pastes of flour and starch during cooking in an RVA instrument and their gel and other properties have been discussed.

Calorimetry, Differential Scanning↗
PubMed2000

Significant increase in prostaglandin E-main urinary metabolite by laxative administration: comparison with ulcerative colitis.

OBJECTIVE: To assess the production of prostaglandin E(2), an important chemical mediator in diarrhea induced by laxative administration, a prostaglandin E-main urinary metabolite (7alpha-hydroxy-5,11-diketotetranor-prosta-1,16-dioic acid, PGE-MUM) was measured in healthy volunteers and compared with the values of patients with ulcerative colitis. METHODS: PGE-MUM was determined by a simplified immunoassay of bicyclic PGE-MUM and analyzed for the influence of laxative administration and active/remission phases of ulcerative colitis. RESULTS: Administration of laxatives induced a significant increase in PGE-MUM in healthy volunteers. A significant elevation was also found in the active as compared with the remission phase of ulcerative colitis. The PGE-MUM levels were significantly correlated with our modified Talstad scores, clinical disease activity indices in ulcerative colitis. It was confirmed by time course studies of individual patients that changes in PGE-MUM correlated well with colitis activity. CONCLUSION: Laxative administration induces production of prostaglandin E(2) as one of the chemical mediators, although its production grade is relatively low as compared with ulcerative colitis in the active phase.

Aged↗
PubMed2000

Thermal perception threshold testing for the evaluation of small sensory nerve fiber injury in patients with hand-arm vibration syndrome.

The aim of the present study was to investigate whether thermal perception threshold testing is a useful method that could replace pain threshold testing in the evaluation of small sensory nerve fiber injury in vibration-induced neuropathy. Vibration, pain, and thermal (warm and cold) perception thresholds were examined on both middle fingers of 50 patients with hand-arm vibration syndrome and 29 healthy controls of similar age. The patients were divided into three subgroups according to the Stockholm Workshop sensorineural scale. Thermal (warm and cold) thresholds as well as vibration and pain thresholds were significantly more deteriorated among the patients than in the controls. Among the patients, warm thresholds elevated and cold thresholds lowered according to the Stockholm Workshop scale. Thermal thresholds were significantly correlated with pain thresholds, and the sensitivity of the thermal threshold testing tended to be greater than that of the pain threshold testing. The present findings indicate that thermal threshold testing for warm and cold perception can be a useful substitute for pain threshold testing to examine small nerve fiber injury in vibration-induced neuropathy.

Arm↗
PubMed2000

[Deregulation of cell cycle control in lung cancer].

Studies on cell cycle regulation and cancer genetics have revealed that multiple cell cycle regulatory proteins play key roles in oncogenesis. These can be categorized in three sets. First; p16INK4-Cyclin D1-RB pathway, which controls G1 to S progression of the cell cycle, second; p53 pathway, which is involved in DNA damage repair, and third; p27KIP1 CDK inhibitor, a negative regulator of cell cycle, and decreased expression of which has been correlated to poor prognosis in cancer patients. Among these, p16INK4, RB and p53 are tumor suppressor genes, and p27 has been pointed out to be haplo-insufficient for tumor suppression. Involvement of these cell cycle regulatory proteins in lung cancer will be discussed.

Animals↗
PubMed1999

p57(Kip2) is degraded through the proteasome in osteoblasts stimulated to proliferation by transforming growth factor beta1.

Cyclin-dependent kinase inhibitory proteins are negative regulators of the cell cycle. Although all the cyclin-dependent kinase inhibitory proteins may be involved in cell cycle control during a differentiation process, only p57(Kip2) is shown to be essential for embryonic development. However, the role of p57 in the control of the cell cycle is poorly understood. Using osteoblasts derived from the calvaria of rat fetus, we show that p57 is accumulated in cells starved by low serum. Cyclin-dependent kinase 2 activity was suppressed in these cells with a significant amount bound to p57. Treatment of the cells with transforming growth factor beta1 dramatically reduced the amount of p57, resulting in an activation of cyclin-dependent kinase 2 activity and the stimulation of cell proliferation. The decrease in p57 was inhibited by treating the cells with proteasome inhibitors, Z-Leu-Leu-Leu-aldehyde or lactacystin, but not with Z-Leu-Leu-aldehyde, which is an inhibitor of calpain, indicating that p57 is degraded through the proteasome pathway. p57 was also shown to be ubiquitinated in vitro. Because transforming growth factor beta1 not only stimulates the growth but also inhibits the differentiation of the cells in this system, our results may suggest a possible involvement of p57 in the control of osteoblastic cell proliferation and differentiation.

Animals↗
PubMed1999

Cerebral blood volume in acute brain infarction: A combined study with dynamic susceptibility contrast MRI and 99mTc-HMPAO-SPECT.

BACKGROUND AND PURPOSE: The aim of this study was to correlate the abnormality in cerebral blood volume (CBV) measured by dynamic susceptibility contrast-enhanced MRI with that in cerebral blood flow (CBF) estimated by single-photon emission CT with [99mTc]hexamethylpropylenamine-oxime in patients with acute ischemic stroke. METHODS: Nine patients with unilateral occlusion of either the middle cerebral artery or the internal carotid artery (4 men and 5 women; mean+/-SD age, 74.4+/-11.6 years) were studied within 6 hours after stroke onset. The relative CBV (relCBV) and CBF (relCBF) in the lesions were defined relative to the contralateral mirror regions. RESULTS: In the brain regions with mild (relCBF >/=0.60), moderate (0.40</=relCBF<0.60), and severe (relCBF <0.40) hypoperfusion, the mean relCBV values were 1.29+/-0.31, 0.94+/-0.49, and 0.30+/-0.22, respectively. The relCBV was significantly elevated in the brain areas with mild hypoperfusion (P<0.001) and significantly reduced in the brain areas with severe hypoperfusion (P<0.001). The relCBF was significantly better than the relCBV in predicting the evolution of infarction (P<0.02). The probability of evolving infarction for the hypervolemic (relCBV >1.0) regions was significantly lower than that for hypovolemic (relCBV <1.0) regions in the relCBF range between 0.40 and 0.50 (P<0.02). CONCLUSIONS: In acute ischemic stroke within 6 hours of onset the CBV can be either increased, normal, or decreased, depending on the severity of hypoperfusion. The increased CBV has a protective effect on evolving infarction. Although the CBF is a better predictor of tissue outcome, the CBV measurement may help detect potentially salvageable brain tissue in the penumbra with compromised blood flow.

Acute Disease↗
PubMed1999

Life-style related factors and idiopathic dilated cardiomyopathy--a case-control study using pooled controls.

A case-control study was conducted to investigate how basic habits of life including dietary habit, physical activity, cigarette smoking, and drinking, are involved in the development of idiopathic dilated cardiomyopathy (DCM). Collection of cases was entrusted to the clinical research group of DCM, and national pooled controls established by sex and age category by the epidemiological research group of intractable diseases were used to ensure representativeness of the controls. Fifty-eight cases of DCM which developed in and after January 1991 were collected, and 5,912 controls matched with the cases by residential area, sex, and age were selected. Analysis of the results of the study showed that items in the questionnaire suggestive of viral infection, such as "susceptibility to common cold" and "susceptibility to diarrhea", items concerning dietary habit, including "taking no breakfast", "ingestion of salty food", and "ingestion of fatty food", and such items as "cigarette smoking" and "lack of sleep" tended to be observed in the case group at significantly higher frequencies. Since viral infection has been suspected as a causative factor of DCM, further research of this area is thought to be of particular importance for determining the etiology of DCM.

Adult↗
PubMed1999

[Lung volume reduction surgery for pulmonary emphysema].

Surgical treatment for pulmonary emphysema has received renewed attention, because many studies have demonstrated improvements in dyspnea and pulmonary function. After lung volume reduction surgery (LVRS) for carefully selected advanced pulmonary emphysema, pulmonary functional impairments, such as expiratory flow limitation, increase in lung volume, decrease in lung elastic recoil, impaired gas exchange are improved. Improvements of dynamic hyperinflation, respiratory muscle function and exercise tolerance were also demonstrated after LVRS for pulmonary emphysema. Finally these functional effects may improve symptom and prognosis of pulmonary emphysema with better quality of life. Although the basic mechanism responsible for the improvements are not well known yet, physiological mechanisms which brought improvement after surgical treatment for pulmonary emphysema should be further investigated.

Exercise Tolerance↗
PubMed1998

The effect of chronic treatment with trandolapril on cyclic AMP-and cyclic GMP-dependent relaxations in aortic segments of rats with chronic heart failure.

1 Characteristics of cyclic GMP- and cyclic AMP-mediated relaxation in aortic segments of rats with chronic heart failure (CHF) and the effects of chronic treatment with an angiotensin I converting enzyme (ACE) inhibitor, trandolapril, were examined 8 weeks after coronary artery ligation. 2 Cardiac output indices of coronary artery-ligated and sham-operated rats were 125+/-8 and 189+/-10 ml min(-1) kg(-1), respectively (P<0.05), indicating the development of CHF at this period. 3 The maximal relaxant response of aortic segments to 10 microM acetylcholine in rats with CHF and sham-operated rats was 64.0+/-5.7 and 86.9+/-1.9%, respectively (P<0.05), whereas the relaxant response to sodium nitroprusside (SNP) remained unchanged. Tissue cyclic GMP content in rats with CHF was lower than that of sham-operated rats. 4 In endothelium-intact segments of rats with CHF, the maximal relaxant response to 10 microM isoprenaline (44.5+/-6.7%) was lower that sham-operated rats (81.3+/-2.5%, P<0.05) and the concentration-response curve for NKH477, a water-soluble forskolin, was shifted to the right without a reduction in the maximal response. Isoprenaline-induced relaxation of aortic segments was attenuated by NG-nitro-L-arginine methyl ester (L-NAME) in sham-operated rats, but not in rats with CHF. Relaxation to 30 microM dibutyryl cyclic AMP in rats with CHF (26.8+/-2.7%) was lower than that in sham-operated rats (63.4+/-11.8%, P<0.05). 5 Trandolapril (3 mg kg(-1) day(-1)) was orally administered from the 2nd to 8th week after the operation. Aortic blood flow of rats with CHF (38.5+/-3.6 ml min(-1)) was lower than that of sham-operated rats (55.0+/-3.0 ml min(-1)), and this reduction was reversed (54.1+/-3.4 ml min(-1)) by treatment with trandolapril. The diminished responsiveness described above was normalized in the trandolapril-treated rat with CHF (i.e., the maximal relaxation to acetylcholine, 94.7+/-1.0%; that to isoprenaline, 80.5+/-2.8%; that to dibutyryl cyclic AMP, 54.7+/-6.2%). However, aortic segments of trandolapril-treated rats with CHF, L-NAME did not attenuate isoprenaline-induced relaxation and the tissue cyclic GMP level was not fully restored, suggesting that the ability of the endothelium to produce NO was still partially damaged. 6 The results suggest that vasorelaxation in CHF, diminished mainly due to dysfunction in endothelial nitric oxide (NO) production and cyclic AMP-mediated signal transduction, was partially restored by long-term treatment with trandolapril. The mechanism underlying the restoration may be attributed in part to prevention of CHF-induced endothelial dysfunction.

Acetylcholine↗
PubMed1998

Modulation of cAMP-mediated vasorelaxation by endothelial nitric oxide and basal cGMP in vascular smooth muscle.

Recent in vitro evidence shows a role of endothelial nitric oxide (NO) in the modulation of isoproterenol-induced vasorelaxation. To elucidate roles of endothelial cells and NO in cyclic adenosine monophosphate (cAMP)-mediated vasodilators we examined the effects of removal of endothelium and a NO synthase (NOS) inhibitor on relaxant responses in vitro of rat aortic strips to beta-adrenoceptor stimulants and colforsin dapropate, a water-soluble forskolin, and changes in cAMP and cyclic guanosine monophosphate (cGMP) contents. Relaxant responses of rat aorta to isoproterenol, denopamine, salbutamol, colforsin, and dibutyryl cAMP (dbcAMP) were blunted by removal of endothelial cells or treatment with NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). Relaxant response of endothelium-intact segments to isoproterenol was associated with increases in tissue cAMP and cGMP contents. Removal of endothelium or treatment with L-NAME markedly reduced basal cGMP and abolished the isoproterenol-induced increase in cGMP but not cAMP content. In endothelium-removed segments, pretreatment with sodium nitroprusside (SNP) restored the diminished relaxant response to isoproterenol and increased basal cGMP (from 0.08 +/- 0.01 to 0.16 +/- 0.02 pmol/mg protein), whereas it did not affect the isoproterenol-induced increase in cAMP. The diminished relaxant response of endothelium-removed segments to dbcAMP was not restored by SNP pretreatment. The results suggest that relaxant response of rat aorta to cAMP-mediated vasodilators is mediated, in part, by NO production in endothelium and subsequent increase in cGMP in vascular smooth-muscle cells.

Adrenergic beta-Agonists↗
PubMed1998

Rheological properties and lipid oxidation of rice decontaminated with low-energy electrons.

Microbial load and quality of rice grains which were exposed to electrons at different acceleration voltages of 170 to 200 kV were examined to evaluate the efficacy of decontaminating rice with low-energy electrons. Electrons at any acceleration voltage between 170 and 200 kV reduced microbial loads of brown rice grains to levels lower than 10 colony-forming units (CFU)/g. Higher acceleration voltages resulted in a lower viscosity and a higher thiobarbituric acid value (TBA). Milling at a yield of 90 or 88% after electron treatment made the viscosity and TBA of rice treated with electrons at 170 kV almost the same as untreated rice. Low and high compression analyses of rice grains which were exposed to electrons at 170 to 180 kV and milled at a yield of 90% followed by cooking showed almost the same hardness and stickiness as untreated grains which were milled at 90%. The results indicate that milling at a yield of 90% or lower removes the portion of rice exposed to electrons at 170 kV and that treatment of brown rice with low-energy electrons enables the preparation of milled rice with extremely low levels of microbial load and little quality deterioration.

Decontamination↗