RESUMEN
Sixteen experimenmtal plots (5 m x 6 m = 30 m2) were designed with four different levels of heavy metals (HMs) concentration in soil. The concentrations of heavy metals in soils, and paddy plant during the different periods of growth were investigated. A relationship between the total HM content in plants and the HM level in soil was found for a wide range of concentrations. The exchangeable fraction of HMs extracted with 1 M MgCl2 solution according to Tessier's method increased correlation with the dosage of supplemented HMs, then decreased as time went on. The time-related variation of exchangeable HMs in soil demonstrated that the amount of effective HMs taken up by paddy differed at various growth phases. The amount of HMs accumulated in different parts of paddy followed the order of root > stem > grain, leaf. The transportation potential of the HMs in paddy in present study followed the order of Zn, Cr > Cd, Cu > Pb. The HM content in root, stem and leaf of paddy plant (dry weight) was low at time of seedling. The concentration in the root increased sharply at time of tillering, decreased thereafter. The concentrations in stem and leaf reached the highest at time of tillering, then decreased, while rose slightly at following time.
Asunto(s)
Productos Agrícolas/metabolismo , Metales Pesados/metabolismo , Contaminantes del Suelo/metabolismo , Suelo/análisis , Contaminantes Químicos del Agua/metabolismo , Transporte Biológico/efectos de los fármacos , Productos Agrícolas/crecimiento & desarrollo , Cloruro de Magnesio/farmacología , Metales Pesados/farmacología , Hojas de la Planta/metabolismo , Raíces de Plantas/metabolismo , Tallos de la Planta/metabolismo , Semillas/metabolismo , Factores de TiempoRESUMEN
Polychlorinated biphenyls (PCBs) are liver-tumor promoters in rodents, but the underlying mechanisms have not been fully elucidated. Tissue sections from the PCB bioassay reported by Mayes et al. 1998, Toxicol Sci., 41-66, were evaluated by histopathological techniques that included immunohistochemistry. In females, and to a much lesser extent in males, iron accumulation in hepatocytes was found at the 26th-week sacrifice, which was pronounced in the mid- and high-dose Aroclor-1254 and -1260 groups. At 52 weeks, large accumulations of iron were also present in Kupffer cells of females, and dose-related increases in proliferating cell nuclear antigen (PCNA) hepatocyte labeling indices were found in both males and females. These changes preceded the formation of liver tumors, which were not generally found until 78 weeks. Glutathione S-transferase placental (GSTP) positive foci were present at 52 weeks in high-dose Aroclor-1254 and -1260 female groups, and small foci were found in some Aroclor 1254-exposed female rats at 26 weeks, along with centrilobular hepatocytes expressing GSTP. The results of this study suggest that PCB-induced iron accumulation in hepatocytes is an early event that may be related to tumor formation, especially in female rats. In both males and females, increases in cell proliferation at 52 weeks were statistically significantly correlated with tumor incidences at termination among the various PCB dosage groups. Consequently, iron accumulations producing oxidative damage, and enhanced cell proliferation resulting in tumor promotion may be components in the mode of action for PCB-induced hepatocarcinogenesis in rodents.
Asunto(s)
Carcinógenos/toxicidad , Hepatocitos/efectos de los fármacos , Hierro/metabolismo , Neoplasias Hepáticas Experimentales/inducido químicamente , Hígado/efectos de los fármacos , Adenocarcinoma/inducido químicamente , Adenocarcinoma/enzimología , Adenocarcinoma/patología , Animales , Pruebas de Carcinogenicidad , División Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Glutatión Transferasa/metabolismo , Hepatocitos/enzimología , Hepatocitos/patología , Inmunohistoquímica , Macrófagos del Hígado/efectos de los fármacos , Macrófagos del Hígado/metabolismo , Hígado/enzimología , Hígado/patología , Neoplasias Hepáticas Experimentales/enzimología , Neoplasias Hepáticas Experimentales/patología , Masculino , Lesiones Precancerosas/inducido químicamente , Lesiones Precancerosas/enzimología , Lesiones Precancerosas/patología , Antígeno Nuclear de Célula en Proliferación/metabolismo , Ratas , Ratas Sprague-Dawley , Caracteres SexualesRESUMEN
We conducted in vitro and in vivo assays in a selenium-deficient system to determine if organic matter (mainly fulvic acid; FA) is involved in a free radical mechanism of action for Kashin-Beck disease. Cartilage cell culture experiments indicated that the oxy or hydroxy functional groups in FA may interfere with the cell membrane and result in enhancement of lipid peroxidation. Experiments with rats demonstrated that toxicity from FA was reduced when the hydroxy group was blocked. Induction of lipid peroxidation by FA in liver and blood of rats was similar to that exhibited by acetyl phenyl hydrazine. FA accumulated in bone and cartilage, where selenium rarely concentrates. In addition, selenium supplementation in rats' drinking water inhibited the generation of oxy-free radicals in bone. We hypothesized that FA in drinking water is an etiological factor of Kashin-Beck disease and that the mechanism of action involves the oxy and hydroxy groups in FA for the generation of free radicals. Selenium was confirmed to be a preventive factor for Kashin-Beck disease.
Asunto(s)
Benzopiranos/efectos adversos , Huesos/efectos de los fármacos , Enfermedades Endémicas , Osteoartritis/inducido químicamente , Contaminantes del Agua/efectos adversos , Abastecimiento de Agua , Animales , Benzopiranos/farmacología , Huesos/metabolismo , Cartílago/efectos de los fármacos , Cartílago/metabolismo , Embrión de Pollo , Femenino , Radicales Libres/metabolismo , Humanos , Peroxidación de Lípido/efectos de los fármacos , Masculino , Malondialdehído/análisis , Ratas , Ratas Endogámicas , Selenio/administración & dosificación , Selenio/deficiencia , Contaminantes del Agua/farmacología , Abastecimiento de Agua/análisisRESUMEN
The chronic toxicity and carcinogenicity of Wingstay 100 (W 100), a rubber antioxidant/antiozonant, were studied in Fischer 344 (F 344) rats in two chronic studies. Earlier genetic studies indicated that the product had weak activity in a bacterial mutation assay, but lacked activity in chromosomal aberration assays. In an one year study, both genders of F 344 rats were exposed to 53, 310 or 1900 ppm in NIH-07 diet for 52 weeks, and sacrifices were made at 38, 52 and 64 weeks. No test substance related deaths occurred, although the high dose of 1900 ppm caused a decrease in body weight gain and food consumption in both genders. Red blood cell mean corpuscular volume was significantly increased at 38 weeks, accompanied by a significant decrease in mean corpuscular hemoglobin concentration. At 52 weeks, the red blood cell count and hemoglobin values were also significantly decreased in high dose animals of both genders. Total bilirubin and cholesterol were increased in high dose animals of 38 and 52-week sacrifices. During the 3 month recovery, hematology parameters, bilirubin and cholesterol returned to control values. Total protein was reduced in high dose animals of both genders, throughout the entire exposure and recovery periods. W 100 also produced increases in relative liver, spleen, heart and kidney weights in high dose animals. Both genders of all W 100 groups exhibited significant increases in urothelial cell proliferation (measured by PCNA) and adaptive hyperplasia. No regenerative hyperplasia, preneoplasia, or neoplasia were present. There was microscopic evidence of extramedullary erythropoiesis in the spleen and liver of high dose animals in both genders, otherwise no other pertinent microscopic finding was evident. In parallel, an accelerated bioassay (ABA) was conducted, which is a mechanistic initiation/promotion carcinogenicity study designed to assess tumor induction and promotion potential of a test substance in major organs of carcinogenesis. The present study was conducted in male F 344 rats for 38 weeks. The target sites chosen for the ABA were liver and urinary bladder and the dose for W 100 was 1900 ppm previously established to be a toxic dose. The liver tumor initiator was diethylnitrosamine (DEN), and the urinary bladder initiator was N-butyl N-(4-hydroxybutyl) nitrosamine (BBN). The initiators were administered during the first 14 weeks followed by the promoters. The promoters, phenobarbital (PB) for the liver and nitrilotriacetate (NTA) for the urinary bladder, were administered during the last 24 weeks of the study after the test substance. The study had 11 test groups including a negative control. The critical comparisons for initiating activity were conducted between groups 3 (PB) and 6 (W 100 + PB) for the liver and groups 8 (NTA) and 11 (W 100 + NTA) for the urinary bladder. The critical comparisons for promoting activity were conducted between groups 2 (DEN) and 5 (DEN + W 100) for the liver and groups 7 (BBN) and 10 (BBN + W 100) for the urinary bladder. There were 26 and 38-week sacrifices. In this study, most body weight reductions were due to DEN. At 26 weeks, significant increases in liver weights were present in all PB-exposed groups. Significant increases in renal weights occurred in all NTA, BBN and DEN groups. A similar organ weight pattern was present at 38 weeks. At 26 weeks, there were hepatocellular (33%) and urothelial (67%) tumors present in positive control groups (DEN/DEN + PB/BBN/BBN + NTA). In contrast, in the DEN + W 100 (5) and the BBN + W 100 (10) groups no tumors were present indicating absence of promotion. In addition, no tumors were present in groups 6 (W 100 + PB) or 11 (W 100 + NTA) indicating absence of initiation. At 38 weeks, the incidences of hepatocellular adenomas and carcinomas in positive control group (DEN) was 44%. The incidence of urothelial adenomas and carcinomas was 67% in group 7 (BBN). In contrast, groups 5 (DEN + W 100) or group 10 (BBN + W 100) had
Asunto(s)
Antioxidantes/toxicidad , Carcinógenos/toxicidad , Fenilendiaminas/toxicidad , Animales , Bilirrubina/sangre , Colesterol/sangre , Índices de Eritrocitos/efectos de los fármacos , Femenino , Riñón/patología , Neoplasias Renales/inducido químicamente , Neoplasias Renales/patología , Hígado/patología , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/patología , Masculino , Miocardio/patología , Neoplasias Experimentales/inducido químicamente , Tamaño de los Órganos/efectos de los fármacos , Fenilendiaminas/administración & dosificación , Ratas , Ratas Endogámicas F344 , Caracteres Sexuales , Bazo/patología , Aumento de Peso/efectos de los fármacosRESUMEN
Oral administration of green or black tea inhibited UVB light-induced complete carcinogenesis in the skin of SKH-1 mice. Green tea was a more effective inhibitor than black tea. Oral administration of decaffeinated green or black tea resulted in substantially less inhibitory activity than did administration of the regular teas, and in one experiment, administration of a high-dose level of the decaffeinated teas enhanced the tumorigenic effect of UVB. Oral administration of caffeine alone had a substantial inhibitory effect on UVB-induced carcinogenesis, and adding caffeine to the decaffeinated teas restored the inhibitory effects of these teas on UVB-induced carcinogenesis. In additional studies, topical application of a green tea polyphenol fraction after each UVB application inhibited UVB-induced tumorigenesis. The results indicate that caffeine contributes in an important way to the inhibitory effects of green and black tea on UVB-induced complete carcinogenesis.
Asunto(s)
Cafeína/farmacología , Flavonoides , Neoplasias Inducidas por Radiación/prevención & control , Neoplasias Cutáneas/prevención & control , Té/química , Rayos Ultravioleta/efectos adversos , Administración Oral , Animales , Carcinoma de Células Escamosas/etiología , Carcinoma de Células Escamosas/prevención & control , Femenino , Queratoacantoma/etiología , Queratoacantoma/prevención & control , Ratones , Ratones Endogámicos , Papiloma/etiología , Papiloma/prevención & control , Fenoles/administración & dosificación , Polímeros/administración & dosificación , Polifenoles , Enfermedades de la Piel/etiología , Enfermedades de la Piel/prevención & control , Neoplasias Cutáneas/etiologíaRESUMEN
Comparative study was performed on the Heart-Qi Deficiency and Blood Stasis type (HQDBS) of hypertensive patients treated with Qigong. The results showed that the clinical symptoms alleviated, cardiac morphology and function, hemorheology and erythrocyte deformity were improved. After one year of practicing Qigong, plasma histofibrinogen activation inhibitor (PAI) and VIII factor related antigen (VIII R: Ag) levels decreased, while plasma tissue fibrinolytic activator (t-PA) and anti-thrombogen III (AT-III) levels increased. Capillary blood velocity of nailfold microcirculation raised from 0.2940 +/- 0.0206 mm/s to 0.3045 +/- 0.0236 mm/s, the diameter and length of afferent limb tended to increase. The above data indicated that Qigong could benefit HQDBS. This might be the mechanism by which HQDBS type of hypertension was treated.
Asunto(s)
Ejercicios Respiratorios , Hipertensión/terapia , Uñas/irrigación sanguínea , Anciano , Viscosidad Sanguínea , Deformación Eritrocítica , Femenino , Humanos , Hipertensión/sangre , Hipertensión/fisiopatología , Masculino , Medicina Tradicional China , Microcirculación , Persona de Mediana Edad , Activador de Tejido Plasminógeno/sangre , Factor de von Willebrand/metabolismoRESUMEN
The levels of plasma tissue-type plasminogen activator (tPA), plasminogen activator inhibitor (PAI), VIII factor related antigen (VIIIR:Ag) and anti-thrombin (AT-III) were determined in 40 hypertensive patients with Blood Stasis. The results indicated that the function of coagulation-fibrinolytic system was disturbed. After one year of practising Qigong, plasma PAI and VIII R:Ag levels were decreased, while plasma tPA and AT-III levels increased. It suggested that Qigong could improve the function of coagulation-fibrinolytic system.
Asunto(s)
Ejercicios Respiratorios , Hipertensión/sangre , Activador de Tejido Plasminógeno/sangre , Anciano , Antitrombina III/metabolismo , Humanos , Hipertensión/terapia , Masculino , Persona de Mediana Edad , Inactivadores Plasminogénicos/metabolismo , Factor de von Willebrand/metabolismoRESUMEN
Ultrasonic cardiogram was performed on 120 aged subjects. Experiment showed that the left ventricular function in the hypertensive aged group (n = 80) was lower than that in the aged group (n = 40), while the left ventricular function in the deficiency of heart-energy hypertensive patients (n = 46) was the lowest in the non-deficiency of heart-energy hypertensive patients (n = 34). After practising Qigong for 1 year, the cardiac output (CO) was increased, the total peripheral resistance (TPR) was decreased, ejection fraction (EF) mitral valve diastolic closing velocity and mean velocity of circumferential fiber shortening (mvcf) tended to be increased. The results indicated that Qigong had a regulatory effect on haemodynamic alteration as well as on improvement of left ventricular function. Nailfold microcirculation detection of 120 aged subjects was made. It found that hypertension had an accelerating effect on the disturbance of microcirculation. The incidence of disturbance of microcirculation was 73.91% in the deficiency of heart-energy hypertensive patients, after 1 year Qigong practice, the incidence of disturbance of microcirculation was 39.13% (P less than 0.01). The result suggested that Qigong had an effect to improve the disturbance of microcirculation. The above data indicate that Qigong can benefit heart-energy and regulate the blood channel.
Asunto(s)
Ejercicios Respiratorios , Hipertensión/terapia , Uñas/irrigación sanguínea , Función Ventricular Izquierda , Anciano , Ecocardiografía , Humanos , Hipertensión/fisiopatología , Masculino , Microcirculación , Persona de Mediana Edad , Deficiencia Yang/terapiaRESUMEN
The serum HDL-C concentration of 100 hypertensive patients had been measured. The results showed that the mean levels of cholesterol (Tc), triglyceride (Tg), LDL-C and AI (AI-Tc-HDL-C/HDL-C) in the serum of male hypertensive patients (n = 100) all were significantly higher than those of male normotensive subjects (n = 50), while the mean levels of serum HDL-C, HDL-C/Tc and HDL-C/LDL-C of male hypertensive patients all were significantly lower than those of male normotensive subjects. The 100 hypertensive patients were also divided randomly into Qigong group (Qigong with regularly antihypertensive drug taking, n = 50) and control group (with regularly antihypertensive drug taking only, n = 50). After one year treatment, in Qigong group, the levels of Tc, Tg, LDL-C and AI were decreased; while the levels of HDL-C, HDL-C/Tc and HDL-C/LDL-C were significant increased. In control group, however, no significant changes were found. The differences between the two groups both were statistically significant (P less than 0.05-0.001). The above results indicated that Qigong practising could elevate serum levels of HDL-C and regulatory metabolism of lipid.