ascorbic-acid and Thyroid-Neoplasms

Topics: Adenoma; Ascorbic Acid; Carcinoma; Cytodiagnosis; Glycogen; Glycosaminoglycans; Goiter, Nodular; Histocytochemistry; Humans; Hyperplasia; Karyometry; Precancerous Conditions; Thyroid Gland; Thyroid Neoplasms; Thyroiditis, Autoimmune

The aim of this study was to evaluate the effect of vitamin E and supragingival scaling with vitamin C on the salivary glands of patients with differentiated thyroid carcinoma after 131I treatment.. A total of 89 prospective patients with differentiated thyroid carcinoma were enrolled and randomly divided into the following groups: vitamin E group (n = 30, group A), vitamin C group (n = 30, group B) and supragingival scaling with vitamin C group (n = 29, group C). Using functional indices (e.g. maximum uptake fraction, uptake index, excretion fraction, secretion time and excretion rate), changes in the salivary gland functions before and a month after 131I treatment were assessed by dynamic imaging of salivary gland.. We compared the before and after 131I therapy results of the three groups. In group A (P  < 0.05), the excretion fraction and excretion rate of the left parotid gland were significantly higher, and the uptake index of the bilateral submandibular glands was significantly lower. No significant changes in salivary gland functional parameters were observed in group B (P > 0.05). The uptake index of the bilateral parotid glands and the excretion rate of the left parotid gland were significantly higher in group C (P < 0.05). The degree of serum amylase level reduction decreased significantly in group C (P < 0.05).. Vitamin E showed a protective effect on parotid excretion function in patients with differentiated thyroid carcinoma who underwent 131I treatment. Supragingival scaling may be a promising radiation protector because it is associated with a protective effect on the salivary gland functions.

Topics: Adenocarcinoma; Ascorbic Acid; Dental Scaling; Humans; Iodine Radioisotopes; Parotid Gland; Prospective Studies; Salivary Glands; Thyroid Neoplasms; Vitamin E

The goal of this study was to evaluate the protective and mitigative effect of vitamin C on oxidative stress in differentiated thyroid cancer (DTC) patients ablated with radioiodine. 58 DTC patients selected for radioactive iodine therapy (RAIT) with 5550 MBq

Topics: Adult; Aged; Ascorbic Acid; Female; Glutathione; Humans; Iodine Radioisotopes; Male; Middle Aged; Oxidative Stress; Radiation-Protective Agents; Superoxide Dismutase; Thyroid Neoplasms; Young Adult

The objective of this study, in addition to confirming that therapy with 131I causes oxidative stress, was to evaluate the effect of supplementation with vitamins C and E and selenium on this phenomenon by measuring plasma 8-epi-PGF2a, a marker of lipid peroxidation.. Forty patients with thyroid cancer submitted to thyroidectomy, who received 3.7 GBq 131I after levothyroxine withdrawal, were selected; 20 patients did not receive (control group) and 20 patients received (intervention group) daily supplementation consisting of 2000 mg vitamin C, 1000 mg vitamin E and 400 µg selenium for 21 days before 131I. Plasma 8-epi-PGF2a was measured immediately before and 2 and 7 days after 131I.. A significant increase in plasma 8-epi-PGF2a after 131I was observed in the two groups. The concentrations of 8-epi-PGF2α were significantly higher in the control group before and 2 and 7 days after 131I. The percentage of patients with elevated 8-epi-PGF2α was also significantly higher in the control group before and after 131I. Furthermore, the increase (percent) in 8-epi-PGF2α was significantly greater in the control group (average of 112.3% versus 56.3%). Only two patients (10%) reported side effects during supplementation.. Ablation with 131I causes oxidative stress which can be minimized by the use of antioxidants.

Topics: Adult; Analysis of Variance; Antioxidants; Ascorbic Acid; Carcinoma; Dietary Supplements; Dinoprost; Female; Humans; Iodine Radioisotopes; Lipid Peroxidation; Male; Middle Aged; Oxidative Stress; Prospective Studies; Reproducibility of Results; Selenium; Thyroid Neoplasms; Thyroidectomy; Thyroxine; Time Factors; Treatment Outcome; Vitamin E; Young Adult

In this study, vitamin C was administered at various times as a sour stimulant to thyroid cancer patients, and the effect on salivary absorbed dose of therapeutic radioiodine ((131)I) was investigated.. Patients with differentiated thyroid cancer who had been prepared for thyroid remnant ablation after total thyroidectomy were prospectively recruited and, using a random-number table, were divided into 4 groups. In the hypothyroid condition, the patients in groups A, B, C, and D began sucking vitamin C (100 mg every 4 h in the daytime over 6 d) at 1, 5, 13, and 25 h, respectively, after receiving 3.7 GBq of (131)I. Scintigraphic images of the head and neck were serially acquired after (131)I administration to assess biokinetics in the salivary glands. Calculation of salivary absorbed dose was based on the MIRD schema of the Society of Nuclear Medicine.. Seventy-two patients (18, 18, 19, and 17 patients from groups A, B, C, and D, respectively) were eligible for the analysis of salivary dosimetry. Differences in absorbed doses to the parotid salivary gland (0.18 +/- 0.11, 0.16 +/- 0.07, 0.16 +/- 0.09, and 0.16 +/- 0.12 mGy/MBq in groups A, B, C, and D, respectively; P = 0.37) and submandibular salivary gland (0.19 +/- 0.05, 0.17 +/- 0.05, 0.18 +/- 0.07, and 0.17 +/- 0.06 mGy/MBq, respectively; P = 0.28) were not statistically significant among groups. Salivary cumulated activities arising from the first 24 h after (131)I administration accounted for 86.08% +/- 7.89% (range, 75%-98%) of total cumulated activities. Differences in salivary absorbed dose during the first 24 h were not statistically significant among the 4 groups either (P = 0.32 and 0.24, respectively, for the parotid and submandibular salivary glands).. Salivary stimulation with vitamin C at any time after (131)I administration has only a limited effect on salivary absorbed dose in thyroid cancer patients.

Topics: Adult; Ascorbic Acid; Eating; Female; Humans; Iodine Radioisotopes; Male; Middle Aged; Prospective Studies; Radiation Dosage; Salivary Glands; Single-Blind Method; Taste Perception; Thyroid Neoplasms; Time Factors

DNA methylation plays an important role in thyroid oncogenesis. The aim of this study was to investigate the connection between global and local DNA methylation status and to establish the levels of important DNA methylation regulators (TET family and DNMT1) in thyroid tumours: follicular adenoma-FA, papillary thyroid carcinoma-PTC (classic papillary thyroid carcinoma-cPTC and papillary thyroid carcinoma follicular variant fvPTC).. Global DNA methylation profile in thyroid tumours tissue (41 paired samples) was assessed by 5-methylcytosine and 5-hydroxymethylcytosine levels evaluation (ELISA), along with TETs and DNMT1 genes expression quantification. Also, it was investigated for the first time TET1 and TET2 promoter's methylation in thyroid tumours. BRAF V600E mutation and RET/PTC translocation testing were performed on all investigated samples. In vitro studies upon DNA methylation in K1 thyroid cancer cells were performed with demethylating agents (5-AzaC and vitamin C).. TET1 and TET2 displayed a significantly reduced gene expression level in PTC, while DNMT1 gene presented a high level of expression. PTC samples presented increased levels of 5-methylcytosine and low levels of 5-hydroxymethylcytosine. 5-methylcytosine levels were associated with TET1/TET2 expression levels. TET1 gene expression was significantly lower in patients positive for BRAF mutation and with RET/PTC rearrangement. TET2 gene was found hypermethylated in thyroid carcinoma patients overall, especially in PTC-follicular variant samples (p= 0.0002), where TET2 gene expression levels were significantly reduced (p= 0.0031). Furthermore, the data indicate for all thyroid cancer patients a good sensitivity (81.08%) and specificity (86.49%) regarding the use of TET1 (p< 0.0001), and TET2 (71.79%, 64.10%, p= 0.0001) hypermethylation as biomarkers for thyroid oncogenesis.. These results suggest that TET1/TET2 gene expression and methylation may serve as potential diagnostic tools for thyroid neoplasia. Our study showed that the methylation of TET1 increases in malignant thyroid tumours. fvPTC patients presented lower methylation levels compared to cPTC and could be a discriminatory factor between two cancer types and benign lesions. TET2 is a poorer discriminator between FA and fvPTC, but it can be useful for cPTC identification. K1-cells treated with demethylating agents showed a demethylation effect, especially upon TET2 gene. The cumulative effect of L-AA and 5-AzaC proved to have a potent combined demethylating effect on genes promoter's activation and could open new perspectives for thyroid cancer therapy.

Topics: Adenocarcinoma, Follicular; Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Ascorbic Acid; Azacitidine; Biomarkers, Tumor; Carcinogenesis; Cell Line, Tumor; Dioxygenases; DNA (Cytosine-5-)-Methyltransferase 1; DNA Methylation; DNA-Binding Proteins; Drug Screening Assays, Antitumor; Epigenesis, Genetic; Feasibility Studies; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Mixed Function Oxygenases; Promoter Regions, Genetic; Proto-Oncogene Proteins; Sensitivity and Specificity; Thyroid Cancer, Papillary; Thyroid Gland; Thyroid Neoplasms; Young Adult

Anaplastic thyroid carcinoma (ATC) requires more innovative approaches as the current regimes for therapy are inadequate, also most anticancer drugs cause general suppression of physiological functions. However, therapy with limited nontarget tissue damage is desirable. In the present study, we show prooxidant ability of ascorbic acid, which enhances cytotoxicity induced by juglone. We decipher that juglone-ascorbate combination induces reactive oxygen species-mediated apoptosis leading to cell death in ARO cell line originated from ATC. This combination also affects enzyme activity of catalase, glutathione reductase, and superoxide dismutase destabilizing redox balance in cell and thereby making juglone effective at a lower dose. We also show that juglone-ascorbate combination suppresses cell migration, invasion, and expression of tumor-promoting, and angiogenic genes in ARO cell line, thereby disrupting epithelial-mesenchymal transition ability of the cells. Overall, we show that ascorbic acid increases cytotoxic potency of juglone through redox cycling when used in synergy.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Ascorbic Acid; Cell Line, Tumor; Cell Movement; Drug Resistance, Neoplasm; Drug Synergism; Gene Expression Regulation, Neoplastic; Glutathione; Humans; Inhibitory Concentration 50; Naphthoquinones; Neoplasm Invasiveness; Neoplasm Proteins; Oxidants; Oxidation-Reduction; Oxidative Stress; Oxidoreductases; RNA Interference; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms

Enhanced glucose requirement of cancer cells is associated with an increased glucose transport across plasma membrane that is mediated by a family of facilitated glucose transporter proteins, named GLUTs. GLUT1 is the main transporter in thyroid cancer cells. Glucose is the principal physiological substrate of GLUT1; however, it is also capable of transporting of oxidized form of vitamin C [i.e., dehydroascorbic acid (DHAA) which inside the cells is reduced to ascorbic acid (AA)]. The objective of this study was to determine the effect of normo-, hypo-, and hyperglycemia conditions on GLUT1-dependent intracellular ascorbate accumulation and viability of thyroid cancer cells. GLUT1 seems to be the main DHAA transporter in thyroid cancer cells because its knockdown by RNAi reduced DHAA accumulation by more than 80%. The results showed that in thyroid cancer cells high glucose inhibits both transport of AA and DHAA. Inhibition of vitamin C transport by glucose had a cytotoxic effect on the cells. However, stabilization of vitamin C in one of 2 forms (i.e., AA or DHAA) abolished this effect. These results suggest that cytotoxic effect is rather associated with extracellular accumulation of vitamin C and changes of its oxidation state than with intracellular level of ascorbate.

Topics: Ascorbic Acid; Biological Transport; Cell Line, Tumor; Cell Survival; Dehydroascorbic Acid; Down-Regulation; Gene Expression; Glucose; Glucose Transporter Type 1; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Thyroid Neoplasms

The bystander effect is a feature of low dose radiation exposure and is characterized by a signaling process from irradiated cells to non irradiated cells, which causes DNA and chromosome damage in these 'nearest neighbour' cells. Here we show that a low and short dose of Cr(VI) can induce stem cells, cancer cells and fibroblasts to chronically secrete bystander signals, which cause DNA damage in neighboring cells. The Cr(VI) induced bystander signaling depended on the telomerase status of either cell. Telomerase negative fibroblasts were able to receive DNA damaging signals from telomerase positive or negative fibroblasts or telomerase positive cancer cells. However telomerase positive fibroblasts were resistant to signals from Cr(VI) exposed telomerase positive fibroblasts or cancer cells. Human embryonic stem cells, with positive Oct4 staining as a marker of pluripotency, showed no significant increase of DNA damage from adjacent Cr and mitomycin C exposed fibroblasts whilst those cells that were negatively stained did. This selectivity of DNA damaging bystander signaling could be an important consideration in developing therapies against cancer and in the safety and effectiveness of tissue engineering and transplantation using stem cells.

Topics: Ascorbic Acid; Bystander Effect; Cells, Cultured; Chromium; DNA Damage; Embryonic Stem Cells; Fibroblasts; Fluorescent Antibody Technique; Histones; Humans; Micronucleus Tests; Signal Transduction; Telomerase; Thyroid Neoplasms; Tumor Necrosis Factor-alpha

The levels of lipid peroxidation products (TBARS), non-enzymatic antioxidants and enzymatic antioxidants activity were investigated in plasma and erythrocytes of twenty clinically diagnosed stage II papillary thyroid cancer patients and an equal number of age and sex matched healthy subjects. An increase in the levels of lipid peroxidation products, decrease in non-enzymatic antioxidants levels and enzymatic antioxidant activities in plasma and erythrocytes were detected in papillary thyroid cancer patients as compared to healthy subjects. Impairment in antioxidant defence mechanisms are responsible for enhanced lipid peroxidation observed in plasma and erythrocytes of papillary thyroid cancer patients.

Topics: Adult; Antioxidants; Ascorbic Acid; Carcinoma, Papillary; Case-Control Studies; Catalase; Erythrocyte Membrane; Erythrocytes; Female; Glutathione; Glutathione Peroxidase; Humans; India; Lipid Peroxidation; Male; Middle Aged; Neoplasm Staging; Nutritional Status; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Thyroid Neoplasms; Vitamin E

Substance P as well as many other neuropeptides are synthesized as glycine-extended precursors and converted to the biologically active C-terminal amides by posttranslational modification. The final step of posttranslational processing is catalyzed by peptidylglycine alpha-amidating monooxygenase (PAM). In a previous study, N-substituted homocysteine analogs were found to be potent inhibitors of PAM partially purified from conditioned medium of cultured rat medullary thyroid carcinoma CA-77 cells. These compounds, however, were only modest inhibitors of substance P production in cultured dorsal root ganglion cells, possibly because of poor cell penetration. Several ester derivatives of hydrocinnamoyl-phenylalanyl-homocysteine, one of the most potent PAM inhibitors, were prepared to increase the intracellular accessibility of these compounds. Hydrocinnamoyl-phenylalanyl-(S-benzoyl-homocysteine) benzyl ester was identified as the most potent compound, inhibiting substance P biosynthesis in dorsal root ganglion cells with an IC50 of 2 microM. Inhibition of PAM resulted in a concomitant increase in the glycine-extended substance p (substance P-Gly) precursor peptide. In the presence of 3 microM benzyl ester derivative, the intracellular substance P-Gly level was 2.4-fold higher while the substance P level was 2.1-fold lower than the corresponding peptides in control cells. These results suggest that PAM inhibition represents an effective method for suppression of substance P biosynthesis and, therefore, may have therapeutic utility in conditions associated with elevated substance P levels. Furthermore, PAM inhibition may also prove useful in decreasing other amidated peptides.

Topics: Animals; Animals, Newborn; Ascorbic Acid; Carcinoma, Medullary; Cells, Cultured; Culture Media, Conditioned; Enzyme Inhibitors; Esters; Ganglia, Spinal; Gene Expression; Homocysteine; Indicators and Reagents; Mixed Function Oxygenases; Molecular Structure; Multienzyme Complexes; Neurons, Afferent; Prodrugs; Protein Precursors; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship; Substance P; Thyroid Neoplasms; Tumor Cells, Cultured

Much evidence gathered in the last years involve the free radicals (FR) in the mechanisms of initiation, development of neoplastic transformations in vivo and in vitro, as well as in the activity of specific oncogenes. Most of it comes from the fact that the agents that remove the FR or interfere in the chain of events induced by FR can inhibit the neoplastic process both at cellular and molecular level. The antioxidant and free-radical scavenging activities of vitamin C have been intensely investigated, vitamin C being considered the most important antioxidant protective agent in the plasma. Our study is focused on the changes in lipid peroxides (MDA), free SH groups and the total antioxidative capacity in the plasma of 22 patients with differentiated thyroid cancer operated and treated with 131I, and then given 1 g vitamin C/day along one month. Blood samples were collected before 131I and then 4 days following 131I administration, and after 1 month of vitamin C administration per os. The following results were noted: (1) an increase of MDA concentration after 131I; (2) a decrease in the MDA level after one month of vitamin C administration; (3) an increase in the concentration of free SH groups after 131I; (4) a decrease in the level of free SH after vitamin C, and (5) a non-significant decrease in TAC after 131I and vitamin C. The results confirm the change in the balance between the oxidative and antioxidative factors under the effect of ionizing radiations and suggest the involvement of vitamin C as a protective and/or potentiating factor for the other antioxidative systems.

Topics: Adult; Antioxidants; Ascorbic Acid; Combined Modality Therapy; Female; Humans; Iodine Radioisotopes; Lipid Peroxides; Male; Middle Aged; Postoperative Care; Reactive Oxygen Species; Sulfhydryl Compounds; Thyroid Hormones; Thyroid Neoplasms; Thyroidectomy

The biosynthesis of C-terminal alpha-amidated peptides from their corresponding C-terminal glycine-extended precursors is catalyzed by peptidylglycine alpha-amidating enzyme (alpha-AE) in a reaction that requires copper, ascorbate, and molecular oxygen. Using bifunctional type A rat alpha-AE, we have shown that O2 is the source of the alpha-carbonyl oxygen of pyruvate produced during the amidation of dansyl-Tyr-Val-[alpha-13C]-D-Ala, as demonstrated by the 18O isotopic shift in the 13C NMR spectrum of [alpha-13C]lactate generated from [alpha-13C]pyruvate in the presence of lactate dehydrogenase and NADH. In addition, one-to-one stoichiometries have been determined for glyoxylate formed/dansyl-Tyr-Val-Gly consumed, pyruvate formed/dansyl-Tyr-Val-D-Ala consumed, dansyl-Tyr-Val-NH2 formed/ascorbate oxidized, and dansyl-Tyr-Val-NH2 formed/O2 consumed. Quantitative coupling of NADH oxidation to dansyl-Tyr-Val-NH2 production using Neurospora crassa semidehydroascorbate reductase showed that two one-electron reductions by ascorbate occurred per alpha-AE turnover. The stoichiometry of approximately 1.0 dansyl-Tyr-Val-NH2 produced/ascorbate oxidized observed in the absence of a semidehydroascorbate trap resulted from the disproportionation of two semidehydroascorbate molecules to ascorbate and dehydroascorbate.

Topics: Amino Acid Sequence; Animals; Ascorbic Acid; Carbon Isotopes; Cell Line; Dansyl Compounds; Glyoxylates; Kinetics; Lactates; Magnetic Resonance Spectroscopy; Mice; Mixed Function Oxygenases; Molecular Sequence Data; Multienzyme Complexes; Neurospora crassa; Oligopeptides; Oxygen Isotopes; Rats; Recombinant Proteins; Substrate Specificity; Thyroid Neoplasms; Transfection

Conversion of dansyl-Tyr-Val-Gly to dansyl-Tyr-Val-NH2 by recombinant type A rat 75-kDa peptidylglycine alpha-amidating enzyme (alpha-AE) is inactivated by ascorbate, dehydroascorbate, and hydrogen peroxide in a time- and concentration-dependent manner. Both ascorbate- and dehydroascorbate-mediated inactivation are saturable with apparent kinact/Kinact values of 1.7 and 0.23 s-1 M-1, respectively. Hydrogen peroxide-mediated inactivation is not saturable with a second-order rate constant of 50 s-1 M-1. Peptidyl-Gly substrates, EDTA, and H2O2 scavengers protect against ascorbate-mediated inactivation while EDTA and semidehydroascorbate scavengers protect against dehydroascorbate-mediated inactivation. Under similar conditions, ascorbate, dehydroascorbate, and H2O2 have no effect on the alpha-AE-catalyzed conversion of dansyl-Tyr-Val-alpha-hydroxyglycine to dansyl-Tyr-Val-NH2 which is consistent with the hypothesis that the 75-kDa enzyme consists of distinct peptidyl-Gly hydroxylase and peptidyl-alpha-hydroxyglycine lyase active sites.

Topics: Amino Acid Sequence; Animals; Antioxidants; Ascorbic Acid; Catechols; Cell Line; Dehydroascorbic Acid; Hydrogen Peroxide; Hydrolases; Kinetics; Mice; Mixed Function Oxygenases; Molecular Sequence Data; Multienzyme Complexes; Oligopeptides; Rats; Recombinant Proteins; Thyroid Neoplasms; Transfection

In 1975, we reported the remarkable case of a 42-year-old man with histologically proven widely disseminated reticulum cell sarcoma who, in a remarkably short time, appeared to enjoy not one, but two, complete spontaneous regressions of his fatal illness. Both these regressions coincided exactly in time with intravenous high-dose ascorbate administration, and it seemed reasonable to conclude that this unconventional therapy must have been responsible for his excellent responses. For those interested in spontaneous regressions of cancer and the possible mechanisms, we now report his subsequent progress some 17 years later.

Topics: Adenocarcinoma; Ascorbic Acid; Dose-Response Relationship, Drug; Humans; Lymphoma, Non-Hodgkin; Middle Aged; Neoplasm Regression, Spontaneous; Thyroid Neoplasms

Potential second-stage modifying effects of 8 antioxidants on lung tumorigenesis initiated by N-bis(2-hydroxypropyl)nitrosamine (DHPN) were examined in male F344 rats. After an initial 2-week treatment with DHPN (0.1% in drinking water), rats were administered one of the antioxidants supplemented in the diet for 30 weeks. Although the incidences of lung adenomas were not affected, those of carcinomas were lowered by 2% butylated hydroxyanisole (BHA, 2 rats/20 rats), 1% butylated hydroxytoluene (BHT, 1/20), 0.8% ethoxyquin (EQ, 3/20) and 1% a-tocopherol (a-TP, 2/20) treatments as compared to the control level (9/20), while 5% sodium L-ascorbate (SA), 0.8% catechol (CC), 0.8% resorcinol (RN), and 0.8% hydroquinone (HQ) did not exert any significant effect on incidence. Quantitative analysis of adenomas and carcinomas (numbers and areas of lesions per unit area of lung section) revealed obvious inhibitory effects of SA, CC, and RN as well as BHA, BHT, EQ, and a-TP. Among the antioxidants, BHT exerted the strongest inhibitory activity. In contrast, DHPN-induced thyroid tumorigenesis was significantly enhanced by BHT (14/20) and EQ (20/20) treatments (control = 5/20). Thus the antioxidants showed opposite effects on lung and thyroid carcinogenesis in the rat.

Topics: Adenoma; Animals; Antioxidants; Ascorbic Acid; Body Weight; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Carcinoma; Catechols; Ethoxyquin; Hydroquinones; Kidney Neoplasms; Lung Neoplasms; Male; Nitrosamines; Organ Size; Rats; Rats, Inbred F344; Resorcinols; Thyroid Neoplasms; Urinary Bladder Neoplasms; Vitamin E

Rats were treated for 1 week each with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), 0.2% N-bis(2-hydroxypropyl)-nitrosamine (DHPN) and 0.2% N-ethyl-N-hydroxyethylnitrosamine (EHEN) in the drinking water, and then administered diet containing 5% sodium L-ascorbate (Na-AsA), 1% butylated hydroxytoluene (BHT) or 0.05% phenobarbital (PB), or weekly intraperitoneal injections of 2 mg of pepleomycin per kg body weight until week 36. Histopathological examination revealed that all exerted significant modulation effects on tumor development in the various target organs. Na-AsA was found to inhibit liver but promote renal pelvis and bladder carcinogenesis. BHT similarly decreased liver and enhanced bladder lesion development. PB, in contrast promoted hepatocarcinogenesis. However both PB and BHT were associated with increased incidences of adenomas and adenocarcinomas of the thyroid. Thus the wide-spectrum initiation model allowed confirmation of site-specific modification potential and in addition demonstrated potentiation of kidney and bladder carcinogenesis promotion by pepleomycin.

Topics: Animals; Ascorbic Acid; Bleomycin; Body Weight; Butylated Hydroxytoluene; Cocarcinogenesis; Kidney Neoplasms; Liver Neoplasms; Lung Neoplasms; Male; Neoplasms, Experimental; Peplomycin; Phenobarbital; Rats; Rats, Inbred F344; Thyroid Neoplasms; Urinary Bladder Neoplasms

Topics: Adult; Ascorbic Acid; Binding, Competitive; Calcitonin; Carcinoma; Humans; Kidney Failure, Chronic; Radioimmunoassay; Thyroid Neoplasms; Urea

A case of reticulum cell sarcoma apparently successfully treated with mega ascorbic acid therapy is described briefly. While the patient continued a large maintenance dose of ascorbic acid, a papillary thyroid carcinoma developed clinically. The role of ascorbic acid in the body resistance to cancer and in tumour prevention is discussed.

Topics: Adult; Ascorbic Acid; Carcinoma, Papillary; Humans; Lymphoma, Large B-Cell, Diffuse; Male; Thyroid Neoplasms

Topics: Adult; Aged; Alkaline Phosphatase; Amyloidosis; Ascorbic Acid; Carcinoma; Glycosaminoglycans; Histocytochemistry; Humans; Lymphatic Metastasis; Male; Methods; Microscopy, Electron; Middle Aged; Nucleic Acids; Thyroid Gland; Thyroid Neoplasms

Topics: Adenocarcinoma, Papillary; Ascorbic Acid; Female; Hemangioendothelioma; Humans; Lymphoma, Non-Hodgkin; Male; Sarcoma; Thyroid Neoplasms