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Biomedical subjects

T Yokozawa

Publications and source records attributed to T Yokozawa.

At least 19 recordsLinked to original sources

Solid tumors after hematopoietic stem cell transplantation in Japan: incidence, risk factors and prognosis.

To evaluate the incidence, risk factors and prognosis for solid tumors after hematopoietic stem cell transplantation (HSCT) in Japan, 809 patients who had received HSCT between 1981 and 2000 were retrospectively analyzed. In all, 19 newly diagnosed secondary cancers were observed. The risk for cancer development was 2.8 times as high as that for expected cases. The cumulative incidence ratios at 5 and 10 years were 1.9 and 4.2%, respectively. The risk was significantly elevated for buccal cavity cancer (standard incidental ratio (SIR), 44.42: 95% confidence interval (CI) 17.86-91.51), esophageal cancer (SIR, 22.36: 95% CI 6.09-57.25), and cervical cancer (SIR, 8.58: 95% CI 1.04-31.01). Of 15 patients who developed solid cancers following allografting, 12 had chronic graft-versus-host disease (GVHD), and all 10 patients with squamous cell carcinoma of the buccal cavity or esophagus had chronic GVHD. On multivariate analysis, extensive chronic GVHD and age over 45 years at the time of transplantation were associated with a higher risk for solid cancers. In all, 17 patients received therapy for secondary cancers, nine of whom are still alive and the 5-year probability of survival from the diagnosis is 42.8%. Our data suggest that early detection of secondary cancers is very important in prolonging overall survival.

Adult↗

Amla (Emblica officinalis Gaertn.) extracts reduce oxidative stress in streptozotocin-induced diabetic rats.

The antioxidant properties of amla extracts and their effects on the oxidative stress in streptozotocin-induced diabetes were examined in rats. Amla in the form of either the commercial enzymatic extract SunAmla (Taiyo Kagaku Co. Ltd., Yokkaichi, Japan) (20 or 40 mg/kg of body weight/day) or a polyphenol-rich fraction of ethyl acetate extract (10 or 20 mg/kg of body weight/day) was given orally for 20 days to the streptozotocin-induced diabetic rats. Amla extracts showed strong free radical scavenging activity. Amla also showed strong inhibition of the production of advanced glycosylated end products. The oral administration of amla extracts to the diabetic rats slightly improved body weight gain and also significantly alleviated various oxidative stress indices of the serum of the diabetic rats. The elevated serum levels of 5-hydroxymethylfurfural, which is a glycosylated protein that is an indicator of oxidative stress, were significantly reduced dose-dependently in the diabetic rats fed amla. Similarly, the serum level of creatinine, yet another oxidative stress parameter, was also reduced. Furthermore, thiobarbituric acid-reactive substances levels were significantly reduced with amla, indicating a reduction in lipid peroxidation. In addition, the decreased albumin levels in the diabetic rats were significantly improved with amla. Amla also significantly improved the serum adiponectin levels. These results form the scientific basis supporting the efficacy of amla for relieving the oxidative stress and improving glucose metabolism in diabetes.

Adiponectin↗

Effect of Wen-Pi-Tang extract on lung damage by influenza virus infection.

The effect of Wen-Pi-Tang extract on influenza virus infection in mice was investigated. The administration of Wen-Pi-Tang extract at a dose of 100mg/kg body wt. for 8 consecutive days to influenza virus-infected mice reversed the lack of body wt. gain and prevented the increase in lung weight caused by the infection in comparison with uninfected mice, while allopurinol, a xanthine oxidase (XOD) inhibitor, did not show these effects. The serum levels of uric acid and allantoin in influenza virus-infected mice were reduced by Wen-Pi-Tang extract administration. Moreover, Wen-Pi-Tang extract reduced the uric acid level more as the dose increased, although it exerted lower activity than allopurinol. The XOD activity of the lungs was elevated by influenza virus infection, but Wen-Pi-Tang extract administration inhibited this activity, indicating prevention of lung damage by oxygen free radicals generated by XOD. After the administration of Wen-Pi-Tang extract to influenza virus-infected mice, the lung superoxide dismutase activity was not significantly different from that of uninfected mice, whereas lung catalase activity was lower in the former than the latter, but slightly higher than that of influenza virus-infected mice, suggesting that Wen-Pi-Tang extract may prevent the generation of highly toxic hydroxyl radicals in the lung. In addition, the administration of both Wen-Pi-Tang extract and allopurinol reduced the degree of lung consolidation caused by influenza virus infection. In particular, Wen-Pi-Tang extract reduced the consolidation score in a dose-dependent manner and more markedly than allopurinol did. This study suggests that Wen-Pi-Tang extract could improve pathological conditions of the lungs induced by influenza virus infection.

Allantoin↗

The role of Coptidis Rhizoma extract in a renal ischemia-reperfusion model.

The effect of Coptidis Rhizoma extract on ischemia-reperfusion in rats was examined. The blood levels of urea nitrogen and creatinine increased significantly more in rats subjected to 24-h reperfusion than those subjected to 6-h reperfusion following 1-h ischemia, indicating functional kidney damage was more severe after the longer reperfusion time. These parameters were reduced by oral administration of Coptidis Rhizoma extract. Greater activity was found in rats given the extract for 30 days than in rats given the extract for 10 days prior to ischemia-reperfusion. In addition, the serum malondialdehyde level was lower, while the glutathione/glutathione disulfide ratio and the activities of the antioxidation enzymes, superoxide dismutase and catalase, were higher in rats given Coptidis Rhizoma extract orally for 30 consecutive days prior to 1-h ischemia and 24-h reperfusion in comparison with control rats given water. These results indicate that Coptidis Rhizoma has a protective action against the renal dysfunction caused by the ischemia and reperfusion process. Furthermore, renal DNA of rats given Coptidis Rhizoma extract orally showed a significantly lower DNA fragmentation rate, which was dose-dependent, implying that the extract afforded the kidneys protection against oxidative stress-mediated apoptosis during the process and ameliorated renal function impairment.

Animals↗

Tie-1 tyrosine kinase expression in human thyroid neoplasms.

AIMS: To investigate tie-1 expression in human thyroid neoplasms. Recent studies have demonstrated that receptor-type tyrosine kinases (RTKs) contribute to carcinoma progression. Tie-1 is one of the RTKs and plays a role in angiogenesis, although its pathophysiological significance in human carcinoma is still to be elucidated. METHODS AND RESULTS: Immunohistochemical expression of tie-1 was studied in various thyroid neoplasms. Tie-1 immunoreactivity was only occasionally observed in normal follicular cells. In papillary carcinoma, tie-1 was classified as positive in carcinoma cells in 55.7% of the cases and was more frequently expressed in those of smaller size with an absence of a poorly differentiated lesion. In contrast, tie-1 was positive in only 8.3% of anaplastic carcinoma and no cases of follicular carcinoma or adenoma were positive. CONCLUSIONS: These results suggest that tie-1 has a role in thyroid tumorigenesis, especially in the early phase of papillary carcinoma, but it is not important in the progression of anaplastic carcinoma or follicular tumour.

Carcinoma↗

Cyclooxygenase-2 expression in thyroid neoplasms.

AIMS: Previous studies have demonstrated that cyclooxygenase-2 (COX-2) plays a role in carcinogenesis and carcinoma development. In this study, we investigated its expression in thyroid neoplasms in order to elucidate its role. METHODS AND RESULTS: COX-2 expression was studied immunohistochemically in 20 anaplastic (undifferentiated) carcinomas, 49 papillary carcinomas, 22 follicular carcinomas and 15 follicular adenomas. Positive staining was only occasionally seen in normal follicles or stromal cells. COX-2 over-expression was found in only 20.0% of follicular adenomas and 40.9% of follicular carcinomas. In papillary carcinomas, the incidence (81.3%) was significantly higher (P < 0.0001) than in follicular carcinomas, although COX-2 expression was reduced in cases with old age (P = 0.0190), large size (P = 0.0028), advanced stage (P = 0.0225), satellite tumours (P = 0.0363), and the presence of solid, scirrhous or trabecular growth patterns (P = 0.0018). Undifferentiated carcinomas less frequently over-expressed COX-2 (P = 0.0004), with an incidence of 40.0%. CONCLUSIONS: These results indicate that the up-regulation of COX-2 may contribute predominantly in the early phase of papillary carcinoma progression, whereas it plays a more adjuvant role in follicular carcinoma progression.

Carcinoma↗

Syndecan-1 expression in thyroid carcinoma: stromal expression followed by epithelial expression is significantly correlated with dedifferentiation.

AIM: To investigate the expression of syndecan-1 in thyroid neoplasia. Syndecan-1 is a proteoglycan regulating cell adhesion. Previous studies have demonstrated that decreased expression of syndecan-1 is linked to malignant progression. METHODS AND RESULTS: Syndecan-1 expression in thyroid neoplasia was studied immunohistochemically. Syndecan-1 was expressed in stromal cells as well as neoplastic epithelial cells. Stromal syndecan-1 expression was observed more frequently in papillary carcinomas larger than 10 mm in size than in microcarcinomas and in widely invasive than in minimally invasive follicular carcinomas. Furthermore, poorly differentiated carcinomas showed this phenomenon more than well-differentiated carcinomas, but the expression in undifferentiated carcinomas was similar to that of poorly differentiated carcinomas. Epithelial syndecan-1 expression was more frequently observed in anaplastic (undifferentiated) carcinomas than in papillary and follicular carcinomas. No significant difference in epithelial expression was found between well and poorly differentiated carcinomas, but undifferentiated carcinomas expressed epithelial syndecan-1 more frequently than did poorly differentiated carcinomas. CONCLUSIONS: These results are in contrast to those previously reported for carcinomas at other sites. It is suggested that the role of syndecan-1 in thyroid carcinomas might be unique. Stromal syndecan-1 expression followed by its epithelial expression is significantly related to progression, including dedifferentiation of thyroid carcinoma.

Adenocarcinoma↗

The effects of Coptidis Rhizoma extract on a hypercholesterolemic animal model.

The serum cholesterol (total, free, esterified, low density lipoprotein (LDL) and oxidized LDL) levels of rats fed a diet containing, by weight, 1% cholesterol and 0.5% cholic acid increased, as compared with those of rats fed a normal diet. The levels, especially of total cholesterol, LDL and oxidized LDL, were reduced significantly in a dose-dependent manner, in rats given Coptidis Rhizoma extract orally at doses of 50 and 100 mg/kg body wt./day for 30 days. These results indicate that Coptidis Rhizoma extract is effective in reducing the pathological damage caused by hypercholesterolemia, through lowering of serum cholesterol levels. In addition, Coptidis Rhizoma extract reduced the level of liver cholesterol, but it did not reduce that of fecal cholesterol, suggesting that the cholesterol level-lowering effect resulted from the reduction of cholesterol synthesis, not the enhancement of its excretion. Furthermore, the serum thiobarbituric acid-reactive substance level decreased after oral administration of Coptidis Rhizoma extract, indicating that Coptidis Rhizoma could prevent hypercholesterolemic disease through reducing lipid peroxidation. This study demonstrates that Coptidis Rhizoma may be a useful therapy for hypercholesterolemia through reducing oxidative stress and cholesterol levels.

Administration, Oral↗

Study on the inhibitory effects of Korean medicinal plants and their main compounds on the 1,1-diphenyl-2-picrylhydrazyl radical.

A 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system was used to evaluate the antioxidant properties of Korean medicinal plants that have been used widely as folk medicines for several disorders, as well as compounds isolated from them. Among the Rosaceae, Rosa rugosa and Rosa davurica showed strong DPPH radical-scavenging activity. The most effective medicinal plant from families other than Rosaceae was Cedrela sinensis, followed in order by Nelumbo nucifera, Eucommia ulmoides, Zanthoxylum piperitum, Cudrania tricuspidata and Houttuynia cordata. These results serve as a good index of the free radical-scavenging activities of Korean medicinal plants. Furthermore, the polyphenols isolated from these plants, procyanidin B-3, (+)-catechin, gallic acid, methyl gallate, quercetin, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-galactoside, quercetin-3-O-rutinose and kaempferol, exerted strong DPPH radical-scavenging activity. These results suggest that the Korean medicinal plants and the polyphenols isolated from them that exhibited effective radical-scavenging activity may be promising agents for scavenging free radicals and treating diseases associated with excess free radicals.

Biflavonoids↗

Expression of cdc25A and cdc25B proteins in thyroid neoplasms.

Cdc25B and cdc25A phosphates are prominent stimulators of cell cycle progression and recent studies have also suggested their oncogenic roles. To elucidate the role of these proteins in thyroid neoplasms, we immunohistochemically investigated their expression, and neither protein was expressed in normal follicular cells. Cdc25B was frequently overexpressed in follicular adenoma and minimally invasive follicular carcinoma, but the incidence was significantly lower in widely invasive follicular carcinoma. Furthermore, the cdc25B expression level significantly decreased with the dedifferentiation of thyroid carcinoma. Cdc25A overexpression was observed in high incidences in all types of thyroid neoplasms. These results suggest that cdc25B and cdc25A play oncogenic roles in thyroid follicules and that cdc25B works predominantly in the early phase of the progression of thyroid carcinoma, whereas cdc25A plays a fundamental role in the development of thyroid neoplasms.

Adenoma↗

Caveolin-1 overexpression is an early event in the progression of papillary carcinoma of the thyroid.

Caveolin-1 is a major structural component of caveolae, which are plasma membrane microdomains implicated in the regulation of intracellular signalling pathways. Previous in vitro and in vivo studies on the function of caveolin-1 in carcinoma showed controversial results, indicating that the physiological role of caveolin-1 varies according to the origin of carcinoma. In this study, we investigated caveolin-1 expression in thyroid neoplasms by means of immunohistochemistry using a rabbit polyclonal antibody against caveolin-1. Normal follicular cells did not express caveolin-1. In papillary carcinoma, caveolin-1 expression was observed in high incidence, and especially in microcancer (less than 1.0 cm in diameter), caveolin-1 was positive in all cases except one. In undifferentiated (anaplastic) carcinoma, its incidence was significantly reduced. On the other hand, all cases of follicular carcinoma and adenoma were classified as negative for caveolin-1. These results suggest that caveolin-1 may play a role predominantly in the early phase of papillary carcinoma, whereas it has little influence on follicular tumours.

Adenoma↗

Direct scavenging of nitric oxide and superoxide by green tea.

In the present study, we investigated the free radical scavenging effects of green tea extract and green tea tannin mixture and its components using a nitric oxide (NO) and superoxide (O(2)(-)) generating system in vitro. Green tea extract showed direct scavenging activity against NO and O(2)(-) and green tea tannin mixture, at the same concentration, showed high scavenging activity. Comparison of the activities of seven pure compounds isolated from green tea tannin mixture showed that (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg) and (-)-epicatechin 3-O-gallate (ECg) had higher scavenging activities than (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC) and (+)-catechin (C), showing the importance of the structure of flavan-3-ol linked to gallic acid for this activity. Among the gallate-free tannins, EGC and GC were more effective O(2)(-) scavengers than EC and C, indicating the O-trihydroxy structure in the B ring is an important determinant of such activity. However, this structure did not affect the NO scavenging activity. These findings confirm that green tea tannin has excellent antioxidant properties, which may be involved in the beneficial effect of this compound.

Catechin↗

Constitutive kinase activation of the TEL-Syk fusion gene in myelodysplastic syndrome with t(9;12)(q22;p12).

The TEL gene on 12p12-13 is a target for a number of translocations associated with various hematological malignancies. The fusion of the TEL gene to the Syk gene in a patient with myelodysplastic syndrome (MDS) with t(9;12)(q22;p12) is reported. Southern blot analysis of patient bone marrow cells with TEL and Syk gene probes detected rearranged fragments. Anchored polymerase chain reaction identified the Syk gene, a nonreceptor tyrosine kinase, on 9q22 fused downstream of TEL exon 5. The TEL gene was fused in-frame to Syk and produced a fusion protein that was constitutively phosphorylated in tyrosine with dimerization that was mediated by the helix-loop-helix domain of TEL. A TEL-Syk fusion product transformed the murine hematopoietic cell line BaF3 to interleukin-3 growth factor independence. TEL-Syk is a novel transforming protein and leads to the transformation of hematopoietic cells. These data implicate that the rearranged Syk gene is involved in the pathogenesis of hematopoietic malignancies.

Amino Acid Sequence↗

Animal model of diabetic nephropathy.

Injection of subtotally nephrectomized rats with streptozotocin produced metabolic abnormalities resembling diabetic nephropathy in humans. These abnormalities were hyperglycemia, hypoinsulinemia, azotemia, hypertriglyceridemia and hypercholesterolemia, accompanied with an increase in glycosylated protein. Extraordinary changes in the urinary excretion of glucose and protein were also observed in rats that received streptozotocin treatment after subtotal nephrectomy. In addition, the level of creatinine clearance was significantly decreased. The pathological findings in the kidney of these rats revealed lesions of the glomerular capillary loops, mesangial area and Bowman's capsule. Coagulation was also found in the glomerular capillaries. Our results suggest that this rat model would be useful for studies of diabetic nephropathy.

Animals↗

Effects of hokoei-to (pugongying-tang), a Kampo formula, on monoamine content in brain regions and mitogenic activity of splenic lymphocytes in ovariectomized mice.

Hokoei-to (pugongying-tang) is one of the Kampo formulae clinically used for gynecological disturbances such as lack of lactation and mammary swelling. We investigated the effect of hokoei-to on the nervous and immune systems in ovariectomized mice as a climacteric disorder model. Hokoei-to suppressed the decrease of monoamines in the ventral hippocampus and dorsal hippocampus of ovariectomized mice. It was shown that the hokoei-to could improve the metabolic turnover of dopamine. The mitogenic activity of lymphocytes in the spleen was reduced after ovariectomy; a suppression of this reduced activity was observed in the group given hokoei-to.

3,4-Dihydroxyphenylacetic Acid↗