The promoting effect of sodium L-ascorbate on two-stage urinary bladder carcinogenesis in F344 rats initiated with A/-butylA/-(4-hydroxybutyl)nitrosamine at levels of 0.01 and 0.05% in drinking water was studied. Administration of 5.0% but not of 1.0% sodium L-ascorbate in the diet significantly increased the incidence and number of preneoplastic lesions, papillary or nodular hyperplasia, papil...

The effect of ascorbic acid on the synthesis, distribution and sulphation of glycosaminoglycans by human skin fibroblasts has been examined. Medium was supplemented with ascorbate over several days, and cultures incubated with [3H]glucosamine and Na2(35)SO4 for 48 h, followed by analysis of the glycosaminoglycans in the medium, in collagenase and trypsin extracts, and in cell fractions. Ascorba...

After prolonged exposure to ascorbate, collagen synthesis in cultured human skin fibroblasts increased approximately 8-fold with no significant change in synthesis of noncollagen protein. This effect of ascorbate appears to be unrelated to its cofactor function in collagen hydroxylation. The collagenous protein secreted in the absence of added ascorbate was normal in hydroxylysine but was mildl...

Studies of recurrent stone formers indicated that they have significantly increased urinary oxalate and decreased ascorbate excretions. Results of oral and intravenous administration of ascorbate indicate an enhanced production of oxalate from ascorbate in recurrent calcium stone formers as compared with normal persons and that most of this oxalate is generated in the gut.

TO THE EDITOR: Research has shown that intravenous, but not oral ascorbate, can produce concentrations selectively toxic to cancer cells, which has renewed the interest in ascorbate as therapy for cancer.1,2 The protocol was approved by the ethics committee of The Center for Improvement of Human Functioning, Wichita, KS. Written informed consent was obtained. Methods. We conducted a mini-pilot ...

BACKGROUND Ascorbate and glutathione play central roles in the defense against free radicals and oxidants that are implicated in chronic diseases. OBJECTIVE The objective was to determine the ability of vitamin C supplements to modulate the concentration of glutathione in human lymphocytes. DESIGN The effect of vitamin C supplements was determined in a sequential study with time points befo...

In recent years, increasing evidence has emerged demonstrating that high-dose ascorbate bears cytotoxic effects on cancer cells in vitro and in vivo, making ascorbate a pro-oxidative drug that catalyzes hydrogen peroxide production in tissues instead of acting as a radical scavenger. This anticancer effect of ascorbate is hypoxia-inducible factor-1α- and O2-dependent. However, whether the intra...

Background: Ascorbate and glutathione play central roles in the defense against free radicals and oxidants that are implicated in chronic diseases. Objective: The objective was to determine the ability of vitamin C supplements to modulate the concentration of glutathione in human lymphocytes. Design: The effect of vitamin C supplements was determined in a sequential study with time points befor...

Liposomes have been intensively investigated as carriers for different applications in dermatology and cosmetics. Ascorbic acid has potent antioxidant and anti-inflammatory properties preventing photodamage of keratinocytes; however, due to its instability and low skin penetration, an appropriate carrier is mandatory to obtain desirable efficacy. The present work investigates the ability of a s...

The extracellular fluid of the striatum contains a high level of ascorbate, an antioxidant vitamin known to play a key role in behavioral activation. We assessed the extracellular dynamics of ascorbate in R6/2 mice engineered to express the gene for Huntington's disease (HD), an autosomal dominant condition characterized by the loss of striatal neurons. Slow-scan voltammetry was used to measure...