Chemical and biochemical aspects of the glycosaminoglycans and proteoglycans in health and disease

Anticancer potential of dietary vitamin D and ascorbic acid: A review

Cancers have been the leading cause of death worldwide and poor diet and physical inactivity are major risk factors in cancer-related deaths. Micronutrients such as vitamins and minerals appear to have preventive properties against cancer. One important mechanism by which dietary changes can exert preventive effects on cancer is via the modulation of micronutrient concentrations in target tissues. Many of these micronutrients are available in the form of dietary supplements, and the intake of these supplements is prevalent in various parts of the world. However, in most cases, it is not known which micronutrient (or combination of micronutrients) is best when it comes to lowering the risk of cancer. The present review illustrates the effect of vitamin D and ascorbic acid intake on preventing cancer.

Orthomolecular Oncology Review: Ascorbic Acid and Cancer 25 Years Later

The effect of ascorbic acid on cancer has been a subject of great controversy. This is a follow-up review of the 1979 article by Cameron, Pauling, and Leibovitz published in Cancer Research. In this updated version, the authors address general aspects of ascorbic acid and cancer that have been presented before, while reviewing, analyzing, and updating new existing literature on the subject. In addition, they present and discuss their own mechanistic hypothesis on the effect of ascorbic acid on the cancer cell. The objective of this review is to provide an updated scientific basis for the use of ascorbic acid, especially intravenously as adjuvant treatment in pharmacological nutritional oncology.

Significance of glycosaminoglycans for the formation of calcium oxalate stones

Glycosaminoglycans (GAG) are polysaccharide chains composed of repeating disaccharides of identical composition. Little is known about the mechanism of their excretion, but there is no doubt that urinary GAGs are degradation products of high molecular weight proteoglycans. Renal excretion takes place chiefly as glomerular filtration, and tubular reabsorption or secretion has not been demonstrated. Differences in the literature comparing GAG excretion in urolithiasis patients and healthy subjects are mainly attributable to methods of analysis and noncomparability of the investigation conditions. We found no differences between the two groups in several series. It is interesting to note that GAG excretion in men is significantly higher than in women, that a circadian rhythm of GAG concentration and excretion occurs in healthy subjects on a standardized diet, and that values are raised postprandially and at night. Seasonal course of GAG excretion curves is almost synchronous for men and women, irrespective of the absolute values, and GAG excretion in the spring and summer significantly exceeds that in winter months by up to 50%. All crystallization models cited demonstrate that GAG reduce the risk of calcium oxalate stone formation. Inhibitors of crystal growth and aggregation act by blocking the growth sites. Inhibition of calcium oxalate crystallization is also attributed to direct binding of calcium to GAG. In the presence of urate ions, and favorable pH, the ability of chondroitin sulfate C to bind calcium may be impaired by as much as 31%. These measurements support the concept that urate ions interact with GAG in urine.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of glycosaminoglycans on the crystallisation of calcium oxalate

The effect of glycosaminoglycans on urinary stone formation was evaluated using a mixed suspension, mixed product removal (MSMPR) crystallisation system together with scanning electron microscopy (SEM) to examine the resulting crystals. Chondroitin sulphate was found to decrease the nucleation rate and to promote both the growth rate and suspension density. Results obtained with hyaluronic acid, although inconclusive, are similar to those given by chondroitin sulphate. Heparin sodium salt had a powerful inhibitory effect on both the nucleation rate and the suspension density, the effect increasing in proportion to the heparin concentration. SEM examination showed that the octahedral habit of calcium oxalate dihydrate was modified by the addition of heparin sodium salt and confirmed that the average crystal size in the presence of chondroitin sulphate and hyaluronic acid was significantly greater than the control or that found in the presence of heparin sodium salt.

Aortic connective tissue in ageing--a biochemical study

The biochemical analysis of samples of aortic connective tissue was carried out in 22 subjects from 9 to 84 years old. Aortic samples were taken at necropsy performed after sudden or, more often, traumatic death. The results suggest that aging of the aorta is accompanied by an increase both in collagen content and in total sugar content when expressed as mg/cm2 while the elastin content, when expressed in the same way, does not undergo any variation.

The distribution of the glycosaminoglycans in the anatomic components of the lung and the changes in concentration of these macromolecules during development and aging

The glycosaminoglycans of the normal human and bovine lungs and of the major structural components of these organs (pleura, 'alveoli', peripheral and central bronchi, arteries and veins) were investigated. To carry out this study, a micromethod for the separation and quantitative determination of these macromolecules, namely two-dimensional electrophoresis on cellulose acetate plates, was employed. This procedure made it possible to measure the content of each glycosaminoglycan present in the mentioned anatomic components. In the human lung the distribution of the glycosaminoglycans varies considerably from one component to another: dermatan sulfate was the predominant mucopolysaccharide of the pleura, chondroitin 6-sulfate that of the central bronchi, and heparan sulfate and chondroitin sulfate those of the alveoli. Heparin and keratan sulfate were not detected in any of the structural components. Significant changes in the mucopolysaccharide levels were found during maturation and aging. Further age-related changes were noted between 22 and 39 years. In the bovine lung significant changes in the glycosaminoglycan levels were also observed during growth and aging. Heparin appeared in the lung at an age between 1 and 16 months. Similarities and differences in the total contents and compositions of the glycosaminoglycans between the human and bovine lung were noted.

Glycosaminoglycan patterns in diabetic and toxemic term placentas

Crude glycosaminoglycans were prepared from acetone powder of diabetic, toxemic, and normal term placentas. Glycosaminoglycan composition was determined by electrophoresis and densitometric scanning with and without treatment with testicular hyaluronidase and chondroitinase ABC. The identity of individual glycosaminoglycans was confirmed by the nature of their hexosamine. Glycosaminoglycan content was found to be significantly increased in diabetic placentas and increased to a lesser degree in the toxemic placentas. The amount of hyaluronic acid was elevated in both abnormal tissues, and heparan sulfate was slightly higher in diabetes, while unchanged in toxemia. Dermatan sulfate was markedly reduced in the abnormal placentas while chondroitin 4/6 sulfate was unaltered. An attempt was made to correlate the histopathologic changes reported to occur in these conditions with the alterations in the glycosaminoglycans patterns of placentas.

Development of gel filtration and specific analyses of urinary carbohydrate and protein material

Hitherto investigations into urinary carbohydrate and proteinaceous macromolecular material has largely been restricted to non-dialysable fractions. We found that this limits the investigation to less than 1% of the total material present and we present a method for direct analysis of urine without prior concentration or extraction. This method extends existing techniques allowing deeper investigation into necessary and important chemical aspects of health and disease. The method is based on gel filtration using Bio-Gel P2. Means included to overcome the observed adsorption by the gel matrix of relevant material depend on use of high ionic concentration buffers for column elution. The problems of bacterial contamination of the gel matrix are discussed and the use of presterilised urine samples is proposed to prevent contamination. The coupling of the gel filtration column to three specific automated analyses allows simultaneous determination of uronic acid, neutral sugar and proteinaceous material.

Adsorption of heparin on sodium acid urate

The adsorption of heparin on sodium acid urate powder suspended in aqueous solution was found to be dependent upon the concentration of Ca2+ and Mg2+. It was concluded that heparin adsoprtion on sodium acid urate powder can occur in urine. Speculations are made about the relevance of these observations to calcium oxalate urolithiasis.