PubMed Health⌕ Search

Biomedical subjects

T Yonemoto

Publications and source records attributed to T Yonemoto.

At least 19 recordsLinked to original sources

Ligand-exchange chromatography at zirconium(IV) immobilized on IDA-type chelating polymer gel

Ligand-exchange chromatography of organo-acidic compounds at Zr(IV) immobilized on IDA-type chelating polymer gel using an aqueous mobile phase was studied, to obtain some insight into their retention on zirconia. Zirconium(IV) has no contribution to the retention of phenols, while appreciably enhancing that of benzoic acids and strongly or occasionally irreversibly adsorbing the potentially chelating substances. The presence of two stationary-phase species adsorbing benzoates was confirmed, and the retention over a wide pH range of 3.5-9.5 was quantitatively formulated. The correlation of the retention factor with the Bronsted acidity of samples and its dependence on pH were theoretically explained, and the performance of this chromatographic system was compared with that of zirconia.

Journal Article↗

Effect of sarpogrelate hydrochloride on platelet-derived microparticles and various soluble adhesion molecules in diabetes mellitus.

We measured platelet-derived microparticles, activated platelets, and various adhesion molecules in 48 patients with diabetes mellitus. We also performed a comparative study of these parameters before and after administration of sarpogrelate hydrochloride. The numbers of platelet-derived microparticles and activated platelets were increased significantly in diabetic patients, and CD63-positive platelets were increased in patients with diabetic complications and poorly controlled blood glucose. Soluble adhesion molecules and thrombomodulin were also increased significantly. After administration of sarpogrelate hydrochloride, not only CD62p- and CD63-positive platelets, but also platelet-derived microparticles were decreased significantly. Soluble adhesion molecules and thrombomodulin were also significantly decreased after the treatment. These data suggest that (a) in patients with diabetes, antiplatelet therapy with sarpogrelate hydrochloride is a useful antithrombin therapy because it suppresses the production of intrinsic coagulants by activated platelets; and (b) sarpogrelate hydrochloride decreases endothelial cell damage via adhesion molecules.

Antigens, CD↗

The surgical management of sacrococcygeal chordoma.

BACKGROUND: Complete excision of sacrococcygeal chordoma is necessary at initial surgery due to its poor sensitivity to radiotherapy and chemotherapy. However, due to the anatomic characteristics of this tumor, intralesional excision tends to be employed, resulting in local recurrences in many patients. METHODS: The clinical features and results of surgical treatment of 13 patients with sacrococcygeal chordoma who were treated at the Chiba Cancer Center and Chiba University beginning in 1972 were analyzed. RESULTS: Intralesional excision was performed in eight patients, marginal excision in two patients, and wide excision in three patients. Local recurrence was observed in six patients, with a high proportion occurring in the gluteal muscles attached to the sacrum (the gluteus maximus muscle and piriform muscle). Seven patients died of their disease and six patients were alive with no evidence of disease. The 5-year survival rate was 81.8% and the 10-year survival rate was 29.1%. CONCLUSIONS: It is highly possible that residual chordoma infiltrating the gluteal muscles accounts mainly for the local recurrences. Therefore, a precise preoperative assessment of the tumor infiltration into the gluteal muscles by magnetic resonance imaging is important for the prevention of local recurrence. For complete tumor removal, a radical wide posterior surgical margin of the gluteal muscles should be employed. A less radical anterior surgical margin is sufficient because there is a firm presacral fascia anterior to the sacrum. The appropriate surgical margin for the complete removal of the chordoma differs according to the location of the tumor and tissues involved.

Adult↗

Effect of treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on serum coenzyme Q10 in diabetic patients.

Serum coenzyme Q10 (CoQ10: 2-(3,7,11,15,19,23,27,31,35,39-decamethyl-2,6,10,14,18,22,26,30,34 ,38 -tetracontadecaenyl)-5,6-dimethoxy-3-methyl-1,4-benzoquinone, CAS 303-98-0) and cholesterol levels were measured to assess the effect of cholesterol-lowering therapy in patients with non-insulin-dependent diabetes mellitus (NIDDM). Twenty healthy volunteers, 97 NIDDM patients and 2 patients with familial hypercholesterolemia were studied. None had overt heart failure or any other heart disease. Mean serum CoQ10 concentrations were significantly (p < 0.01) lower in diabetic patients with normal serum cholesterol concentrations, either with or without administration of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HMG-CoA RIs) including simvastatin (normal: 0.91 +/- 0.26 (mean +/- SD) mumol 1(-1); diabetic with HMG-CoA RI: 0.63 +/- 0.19; diabetic without HMG-CoA RI: 0.66 +/- 0.21). CoQ10 concentrations were higher (1.37 +/- 0.48, p < 0.001) in diabetic patients with hypercholesterolemia. Simvastatin or low density lipoprotein apheresis decreased serum CoQ10 concentrations along with decreasing serum cholesterol. Oral CoQ10 supplementation in diabetic patients receiving HMG-CoA RI significantly (p < 0.001) increased serum CoQ10 from 0.81 +/- 0.24 to 1.47 +/- 0.44 mumol 1(-1), without affecting cholesterol levels. It significantly (p < 0.03) decreased cardiothoracic ratios from 51.4 +/- 5.1 to 49.2 +/- 4.7%. In conclusion, serum CoQ10 levels in NIDDM patients are decreased and may be associated with subclinical diabetic cardiomyopathy reversible by CoQ10 supplementation.

Adult↗

Age- and sex-related changes in type-1 iodothyronine deiodinase messenger ribonucleic acid in rat liver and kidney.

To evaluate the age- and sex-related changes in Type 1 iodothyronine deiodinase gene expression in the liver and kidneys, we measured 5'-deiodinating activity and deiodinase mRNA in developing rats. The activity in the liver increased after birth, and that in neonates was approximately half that in adults. In contrast, the activity in neonatal kidneys remained very low. The relative importance of activity in male kidneys compared to the liver increased from the ages of 1 to 20 days. The male adult rat liver showed a higher level of activity than the female liver. Deiodinase mRNA in the male liver gradually increased from 1 to 20 days, in correlation with the activity. In kidneys, deiodinase mRNA was low before day 20, and there was no significant sex difference in all age groups. In orchiectomized male rats, the activity and mRNA in the liver was similar to the low levels found in females; however, the levels in the kidneys were not significantly different than those of normal males. These data suggest that the age- and sex-related changes in iodothyronine deiodinase gene expression are regulated mainly at the pretranslational level, and that the relative importance of kidneys to liver in iodothyronine deiodinase increases from birth to age 20 days due to the difference in the gene expression.

Aging↗

Circadian heart rate rhythms in Japanese centenarians.

OBJECTIVE: To investigate age-associated changes in the circadian rhythm of the heart rate. DESIGN: The circadian rhythm was extracted from diurnal heart rate (HR) variations, and patterns of HR rhythm were compared in centenarians and controls. SETTING: Centenarians living in the metropolitan area of Tokyo and in Aichi prefecture in 1992. PARTICIPANTS: Fifty centenarians underwent 24-hour ambulatory electrocardiogram (Holter) monitoring. The control group, comprised of 100 clinically healthy subjects who underwent similar Holter monitoring, was subdivided, by age, into two groups: the younger controls (age range 23 to 54 years, mean age 41) and the older controls (age range 55 to 82 years, mean age 69). MEASUREMENTS: Harmonic analysis was used to approximate the 24-hour RR interval (the interval between two neighboring R waves on the electrocardiogram) data obtained by Holter monitoring to a summation of three cosine waves with 24-hour, 12-hour, and 8-hour periods. The power of the period was adjusted for the goodness of curve-fit. The power of each period and the circadian acrophase (the timing of the peak in a 24-hour rhythm) were compared among the centenarians, older controls, and younger controls. HR rhythms were classified by k-means cluster analysis based on the power of the period. The prevalence of each pattern was compared among the three age groups. In the centenarians, the relationship between clinical parameters (activities of daily living, cognitive function, nutritional status, and present illness) and patterns of HR rhythm was investigated. RESULTS: The power of the 24-hour period in the centenarians was significantly smaller than that in the older (P < .05) and younger (P < .001) controls. The power of the 8-hour period in the centenarians was significantly larger than that in the younger controls (P < .05). Advances or delays in the circadian acrophase were frequently observed in the centenarians compared with the younger controls. The power of each period did not differ between centenarians with (n = 11) and without (n = 39) overt diseases capable of altering HR rhythms. Five patterns of HR rhythm were identified: 24-hour period dominant (n = 84), 24-hour+12-hour period (n = 18), 12-hour period dominant (n = 11), 8-hour period dominant (n = 7), and low goodness of curve-fit (n = 30). The 8-hour period dominant pattern and the low goodness of curve-fit pattern were observed commonly in the centenarians, whereas the 24-hour period dominant pattern and the 24-hour+12-hour period pattern were observed frequently in the younger controls. Patterns of HR rhythm were not related to clinical parameters in the centenarians. CONCLUSIONS: The circadian rhythm of HR changed with aging: there was reduction in the power of the 24-hour period, augmentation in the power of the 8-hour period, and a shift in the circadian acrophase.

Activities of Daily Living↗

Significance of platelet-derived microparticles and activated platelets in diabetic nephropathy.

We measured levels of platelet-derived microparticles (PMP), which have coagulative activity and are produced by platelet activation or physical stimulation, and CD62P/CD63-positive platelets in patients with diabetes mellitus to determine their clinical significance and effects on complications of diabetes including diabetic nephropathy. We also compared these levels before and after administration of the antiplatelet drug cilostazol. Plasma PMP and CD62P/CD63-positive platelet levels were significantly higher in patients with diabetes mellitus than normal controls. CD62P-positive platelet levels were significantly higher in patients with nephropathy than in patients without complications. After administration of cilostazol, PMP and CD62P/CD63-positive platelet levels were significantly decreased. The increases in platelet activity and its related procoagulant activity appear to account in part for the hypercoagulability observed in diabetes mellitus. Our findings suggest that activated platelets might play a role in the development of diabetic nephropathy. Furthermore, antiplatelet therapy with cilostazol for diabetic patients may be useful as antithrombin therapy including antiplatelet therapy, since it suppresses the production of intrinsic coagulants produced by platelet activation.

Antigens, CD↗

Serum concentration and renal handling of 1,5-anhydro-D-glucitol in patients with chronic renal failure.

We measured serum and urinary 1,5-anhydro-D-glucitol (1,5-AG) during a glucose tolerance test (GTT) in patients with chronic renal failure (CRF) and compared the fractional excretion of 1,5-AG (FEAG) with that of diabetes mellitus (DM) patients and healthy controls. The mean serum 1,5-AG in CRF patients [60 +/- 23(SE) mumol/L] was significantly lower than in controls (155 +/- 7 mumol/L) in spite of a normal glycaemia. The levels in the CRF group were similar to those in the DM group. During GTT, the blood glucose profile in the CRF group was not significantly different from that of the control group, and urinary glucose excretion was negligible. However, FEAG was significantly higher in CRF patients than in controls. These data suggest that serum 1,5-AG in patients with CRF decreases due to a decrease in 1,5-AG reabsorption, independently of glucose excretion, and that serum and/or urinary 1,5-AG can be a useful marker for renal tubular dysfunction because the 1,5-AG reabsorption system is more vulnerable than the glucose reabsorption system.

Biomarkers↗

Effect of nicotine on type 2 deiodinase activity in cultured rat glial cells.

Intracellular generation of triiodothyronine (T3) from thyroxine (T4) by type 2 deiodinase (D2) in the mammalian brain, plays a key role in thyroid hormone action. The presence of D2 in rat astrocytes suggests the importance of glial cells in the regulation of intracellular T3 levels in the rat central nervous system (CNS). To analyze further the factors that regulate D2 activity in the CNS, we investigated the effects of nicotine and of mecamylamine, which inhibits the binding of nicotine with nicotinic acetylcholine receptors, on D2 activity in cultured mixed glial cells of the rat brain. We incubated cultured mixed glial cells obtained from neonatal Wistar rats in the presence of 10 mM dithiothreitol, 2 nM [125I] reverse T3 and 1 mM 6-N-propyl-2-thiouracil for 2 h at 37 degrees C, and the released 125I- was counted in a gamma counter. D2 activity of cultured cells was dependent on the temperature and the amount of protein. The basal D2 activity of rat mixed glial cells was 1.9 +/- 0.2 fmol of I- released/mg protein/h (mean +/- SEM). The addition of 10(-11), 2 x 10(-11), 10(-10), and 10(-9) M nicotine significantly increased D2 activity to approximately 2.2-, 2.4, 3.5- and 2.9-fold the basal level, respectively. D2 activity stimulated by 10(-8) M nicotine (2.5-fold) reached a peak after 9 h incubation. The stimulatory effect of nicotine was completely blocked by 10(-6) M mecamylamine. In conclusion, nicotine increases D2 activity probably via nicotinic acetylcholine receptors, and may influence brain function, at least in part, by affecting thyroid hormone metabolism.

Animals↗

Effect of triiodothyronine administration on reduced expression of type 1 iodothyronine deiodinase messenger ribonucleic acid in streptozotocin-induced diabetic rats.

To examine the mechanism behind a decrease in type 1 iodothyronine deiodinase (D1) gene expression in diabetes mellitus, we evaluated the effect of administering T3 and/or insulin on D1 activity and the mRNA levels in the liver of streptozotocin (STZ)-induced diabetic rats. STZ (100 mg/kg BW) was administered to male Wistar rats, and the rats were divided into four groups as follows: (1) STZ alone, (2) STZ and T3 (5 microg/100 g BW daily for 7 days), (3) STZ and insulin (intermediate-acting insulin, 4 units/100 g BW daily for 7 days), and (4) STZ, T3, and insulin. Blood glucose levels increased in Group 1, but were normalized in Group 3. Serum T3 levels were markedly decreased in Group 1. They were within normal limits 24 hours after the last administration of T3 in Group 2 and after the administration of insulin in Group 3. T3 levels were supranormal in Group 4. TSH levels were normal in Groups 1 and 3, but were suppressed in Groups 2 and 4, suggesting that rats in Groups 2 and 4 were actually in a hyperthyroid state after injecting a large amount of T3. D1 activity in Group 1 was reduced significantly, but it was normal in Groups 2 and 3, and increased in Group 4. D1 mRNA levels in the liver in Group 1 decreased significantly, but they were increased to within normal limits by adding insulin in Group 3. They were also normal in Group 2 where hyperglycemia was evident and rats were hyperthyroid after administering T3. D1 mRNA in Group 4 increased significantly where glucose levels were normal and T3 levels were increased. We suggest that the decrease in hepatic D1 mRNA in STZ-induced diabetic rats is due to metabolic derangement caused by insulin deficiency in addition to a possible decrease in tissue T3 availability.

Animals↗

Effect of streptozotocin-induced diabetes mellitus on type 1 deiodinase (D1) in inherited D1-deficient mice.

We investigated the effects of streptozotocin (STZ)-induced diabetes on thyroid hormone levels, type 1 deiodinase (D1) activity and messenger RNA (mRNA) levels in inherited D1 deficient C3H mice in a comparative manner with control C57 mice. The apparent maximum velocity (Vmax) D1 values in C3H mice were 3% (liver) and 26% (kidney) of those in C57 mice. In C3H mice, similar serum T3, slightly higher T4, and 2.6-fold higher rT3 levels were observed compared with C57 mice. In STZ-induced diabetes, serum T4 level markedly decreased in both C3H and C57 mice. Serum T3 levels in STZ-C3H mice similarly decreased as in STZ-C57 mice. On the other hand, serum rT3 levels increased to 3.3-fold higher in STZ-C3H than in STZ-C57 mice. The Vmax values were decreased to 12% (STZ-C3H) and to 30% (STZ-C57) in liver, and decreased to 33% (both STZ-C3H and STZ-C57) in kidney. The changes in D1 mRNA levels in diabetes versus control were comparable to those of D1 activities in both strains. In summary, similar mechanism(s) to those which decrease the D1 expression and the serum T3 level in diabetes, function in D1 deficient C3H mice as in C57 mice. It appears that hepatic and renal D1 activity alone can not explain the similar reduction in T3 level in STZ-C3H mice and STZ-C57 mice.

Animals↗

Type 1 iodothyronine deiodinase in heart --effects of triiodothyronine and angiotensin II on its activity and mRNA in cultured rat myocytes.

We previously demonstrated that iodothyronine 5'-deiodination (5'D) activity is present and increased by triiodothyronine (T3) and angiotensin II (Ang II) in cultured rat cardiac myocytes. To further elucidate the stimulatory mechanism of Ang II, we investigated the effect of intracellular Ca2+ and protein kinase C on myocardial 5'D activity. Moreover, to elucidate the molecular mechanism of the stimulatory effect of T3 and Ang II, we detected the mRNA levels by means of a reverse-transcriptase polymerase chain reaction (RT-PCR). 5'D activity was increased by adding Bay-k 8644, Ca2+ channel agonist and the effect of Bay-k 8644 was completely blocked by nifedipine, a Ca2+ channel antagonist. 12-O-tetradecanoylphorbol-13-acetate, a protein kinase C activator, similarly stimulated 5'D activity. The addition of a high concentration (20-40 mM) of K+, which caused the depolarization of the membrane had significant stimulatory effects on 5'D activity. Type 1 deiodinase (D1) mRNA was evident in myocardial cells by RT-PCR in a single 758 bp band similar to that in the liver. Cardiac fibroblasts did not express the D1 mRNA. A significant increase in D1 mRNA was also evident after adding T3 and Ang II. These findings indicate that 5'D activity in myocardial cells is increased by activating the voltage sensitive Ca2+ channel, protein kinase C, and membrane depolarization, and that the D1 mRNA is present in cardiac myocytes and is increased by T3 and Ang II. This study therefore suggests that Ang II could affect the action of thyroid hormone on the heart by increasing the D1 gene expression.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

Primary aldosteronism with aldosterone-producing adrenal adenoma in a pregnant woman.

A 30-year-old pregnant woman complained of muscle weakness at 29 weeks' gestation. She was hypertensive with severe hypokalemia. Lower plasma renin activity and higher aldosterone level than the normal values in pregnancy suggested primary aldosteronism. A cesarean delivery was performed at 31 weeks' gestation because of pulmonary congestion. The neonatal course was uncomplicated. The laparoscopic adrenalectomy for a 2.0-cm right adrenal adenoma resulted in normalizing of her blood pressure and serum potassium level. Although primary aldosteronism is rare, especially during pregnancy, it should be always considered as one of etiologies of hypertension in pregnancy.

Adrenal Cortex Neoplasms↗

Multiple spontaneous small bowel perforations due to systemic cholesterol atheromatous embolism.

A-65-year-old man was admitted for coronary and peripheral angiography to evaluate angina pectoris and peripheral vascular disease. Following angiography, he suffered from blue toes, livedo reticularis and progressive renal failure. The patient's condition continued to deteriorate, including the development of malnutrition. Four months later he suddenly developed panperitonitis, went into shock and died. The autopsy verified multiple perforations of the small bowel with disseminated cholesterol atheromatous embolism. The other organs including kidney were also invaded by atheroembolism. This was a rare case of multiple spontaneous perforations of small bowel due to systemic cholesterol atheromatous embolism.

Acute Kidney Injury↗

[High-dose chemotherapy with autologous peripheral blood stem cell transplantation (PBSCT) for refractory bone and soft tissue sarcomas].

High-dose chemotherapy with autologous peripheral blood stem cell transplantation was administered to 10 patients with refractory bone and soft tissue sarcoma (2 patients with primitive neuroectodermal tumor, 4 patients with Ewing's sarcoma, 3 patients with synovial sarcoma and one patient with osteosarcoma). Busulfan 4 mg/kg x 4, melphalan 140 mg/m2 and thiotepa 200 mg/m2 x 3 were used in the high-dose chemotherapy. Complications related to the treatment were limited to one patient who developed hepatic veno-occlusive disease, no serious complications were seen in the other patients. Four patients died of their disease, one patient was alive with the disease and 5 patients were alive with no evidence of disease. The prognosis for non-resectable primitive neuroectodermal tumor and Ewing's sarcoma is said to be very poor. However, there are some patients in whom the disease is kept in remission by high-dose chemotherapy with autologous peripheral blood stem cell transplantation, so this therapy may be a possible substitute for radical operation. With spindle cell sarcomas, the efficacy of this treatment was temporary, so it will be necessary to investigate frequent high-dose chemotherapy and to change the high-dose chemotherapy regimen.

Adolescent↗

Quantitative measurements for type 1 deiodinase messenger ribonucleic acid in human peripheral blood mononuclear cells: mechanism of the preferential increase of T3 in hyperthyroid Graves' disease.

To evaluate the regulatory mechanism of human Type 1 iodothyronine deiodinase (D1) gene expression, we measured the D1 mRNA levels in peripheral blood mononuclear cells (PBMC) in normal control subjects and in patients with Graves' disease. We used competitive reverse transcriptase-polymerase chain reaction with the deleted complimentary RNA of D1 as the standard for quantification. The D1 mRNA levels in PBMC were increased significantly in patients with Graves' disease compared with that in normal controls. There was a significant (p < 0.01) positive correlation (r=0.698) between D1 mRNA level and serum T3 concentration. When PBMC from the normal volunteers were cultured with various doses of T3, the quantity of D1 mRNA increased significantly in a dose-dependent manner. These findings indicate that PBMC D1 mRNA is actually up-regulated by T3 in vivo, and we postulate that a vicious spiral of increasing T3 and D1 is responsible for the exacerbation of thyrotoxicosis in hyperthyroid Graves' disease.

Gene Expression Regulation↗

Maternal thyroid function in multiple pregnancy: the variable thyrotropic activity of human chorionic gonadotropin.

The present study was undertaken to evaluate thyroid function and thyrotropic action of hCG in multiple pregnancy. We examined serum samples from 9 multiple pregnant women (3 triplets and 6 twins) and 27 singleton pregnant women as control subjects. Serum hCG levels in multiple pregnancy were higher than those in singleton pregnancy in the second and third trimesters (P < 0.01). The mean free T3 and T4 concentrations in multiple pregnancy did not differ from those in singleton pregnancy in each trimester. Serum hCG levels showed a statistically significant positive correlation with free T3 and T4 levels in singleton pregnancy (P < 0.001). However, these correlations were not observed in multiple pregnancy. Thyroid stimulation activity (TSA) determined by cAMP accumulation in FRTL-5 cells in multiple pregnancy sera was significantly higher than that in singleton pregnancy in the first trimester (P < 0.05), but did not differ in the second and third trimesters. Moreover, TSA did not show any correlation with serum hCG levels in multiple pregnancy in contrast with the results in normal pregnancy. A bioactivity/immunoreactivity ratio of hCG in multiple pregnancy was lower than in singleton pregnancy in the second and third trimesters. The discrepancy between immunoreactivity and thyrotropic activity of hCG may be caused by the variable thyrotropic potency of heterogeneous hCG molecules in multiple pregnancy.

Adult↗

Induction of type 2 deiodinase activity by cyclic guanosine 3',5'-monophosphate in cultured rat glial cells.

We investigated the effects of cyclic guanosine 3',5'-monophosphate (cGMP) on type 2 iodothyronine deiodinase (D2) in cultured rat glial cells. Rat glial cells were cultured in Dulbecco's modified Eagle's medium supplemented with 15% fetal bovine serum. When cells were cultured in the presence of 8-bromo cGMP (8-Br cGMP), an analogue of cGMP, D2 activity was increased in a time- and concentration-dependent manner. Lineweaver-Burk plots revealed that the stimulation of D2 activity by 8-Br cGMP (10(-3) M) was associated with fivefold increase in maximum velocity but without a significant change in Michaelis-Menten constant, suggesting that cGMP increases D2 activity via new enzyme synthesis. Both atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) are well known to increase the intracellular cGMP level via their guanylate cyclase-linked receptors in rat glial cells. In the present study, ANP (10(-6) M) and CNP (10(-6) M) significantly increased the D2 activity in rat glial cells (1.9-fold [ANP] or 2.3-fold [CNP] compared with control activity, respectively). Northern blot analysis demonstrated that D2 mRNA level increased in the presence of 8-Br cGMP (10(-3) M), and reached a plateau (six-fold) after 4 hours of incubation. The increment of D2 mRNA level by 8-Br cGMP was comparable with the increase of the D2 activity by this agent. Our data suggest that cGMP induces rat D2 activity, at least in part, at the pretranslational level, and that ANP and CNP increase D2 activity most likely via their guanylate cyclase-linked receptors in rat glial cells.

8-Bromo Cyclic Adenosine Monophosphate↗