I read this book the same weekend that the Packers took on the Rams, and the experience of the latter event, obviously, colored my judgment. Although I abhor anything that smacks of being a handbook (like, \"How to Earn a Merit Badge in Neurosurgery\") because too many volumes in biomedical science already evince a boyscout-like approach, I must confess that parts of this volume are fast, scholarly, and significant, with certain reservations. I like parts of this well-illustrated book because Dr. Sj6strand, without so stating, develops certain subjects on technique in relation to the acquisition of judgment and sophistication. And this is important! So, given that the author (like all of us) is somewhat deficient in some areas, and biased in others, the book is still valuable if the uninitiated reader swallows it in a general fashion, realizing full well that what will be required from the reader is a modulation to fit his vision, propreception, adaptation and response, and the kind of problem he is undertaking. A major deficiency of this book is revealed by comparison of its use of physics and of chemistry to provide understanding and background for the application of high resolution electron microscopy to problems in biology. Since the volume is keyed to high resolution electron microscopy, which is a sophisticated form of structural analysis, but really morphology in a modern guise, the physical and mechanical background of The instrument and its ancillary tools are simply and well presented. The potential use of chemical or cytochemical information as it relates to biological fine structure , however, is quite deficient. I wonder when even sophisticated morphol-ogists will consider fixation a reaction and not a technique; only then will the fundamentals become self-evident and predictable and this sine qua flon will become less mystical. Staining reactions (the most inadequate chapter) ought to be something more than a technique to selectively enhance contrast of morphological elements; it ought to give the structural addresses of some of the chemical residents of cell components. Is it pertinent that auto-radiography gets singled out for more complete coverage than other significant aspects of cytochemistry by a high resolution microscopist, when it has a built-in minimal error of 1,000 A in standard practice? I don't mean to blind-side (in strict football terminology) Dr. Sj6strand's efforts for what is \"routinely used in our laboratory\"; what is done is usually well done. It's just that …

Methods in Enzymology.

Vitamin C is an essential micronutrient for humans, with pleiotropic functions related to its ability to donate electrons. It is a potent antioxidant and a cofactor for a family of biosynthetic and gene regulatory enzymes. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune system. Vitamin C supports epithelial barrier function against pathogens and promotes the oxidant scavenging activity of the skin, thereby potentially protecting against environmental oxidative stress. Vitamin C accumulates in phagocytic cells, such as neutrophils, and can enhance chemotaxis, phagocytosis, generation of reactive oxygen species, and ultimately microbial killing. It is also needed for apoptosis and clearance of the spent neutrophils from sites of infection by macrophages, thereby decreasing necrosis/NETosis and potential tissue damage. The role of vitamin C in lymphocytes is less clear, but it has been shown to enhance differentiation and proliferation of B- and T-cells, likely due to its gene regulating effects. Vitamin C deficiency results in impaired immunity and higher susceptibility to infections. In turn, infections significantly impact on vitamin C levels due to enhanced inflammation and metabolic requirements. Furthermore, supplementation with vitamin C appears to be able to both prevent and treat respiratory and systemic infections. Prophylactic prevention of infection requires dietary vitamin C intakes that provide at least adequate, if not saturating plasma levels (i.e., 100–200 mg/day), which optimize cell and tissue levels. In contrast, treatment of established infections requires significantly higher (gram) doses of the vitamin to compensate for the increased inflammatory response and metabolic demand.

Vitamin C and Immune Function

Oxidative stress induced-neurodegenerative diseases: the need for antioxidants that penetrate the blood brain barrier.

https://www.cell.com/trends/neurosciences/pdf/S0166-2236(99)01543-X.pdf

Ascorbate regulation and its neuroprotective role in the brain

Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

The requirement of ascorbic acid (vitamin C ) is a common property of living organisms, and it has long been considered that all animals except the guinea pig, monkey, and man can synthesize this vitamin. The classic method for determining the ability of an animal to synthesize ascorbic acid is to feed it a scorbutogenic diet for a prolonged period and to observe the appearance of the scurvy syndrome. Obviously, the method is laborious and time-consuming. Also, the onset of the scorbutic syndrome depends on the ascorbic-acid-retention capacity of the animal. For example, whereas the guinea pigs can be made scorbutic in about 3 weeks, it takes 3 to 4 months to produce scurvy in man. Since the discovery of the technique for studying ascorbic acid synthesir in vitro,1-8 the task has become much simpler. In this technique, the tissue homogenates or the subcellular fractions are incubated with precursors of ascorbic acid and the amount of the vitamin formed is estimated. Using the in vitro method, we have examined the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree, and the results are given below.

Synthesis and some major functions of vitamin C in animals.

1. In guinea-pigs fed an ascorbic-acid-free diet, as the ascorbic acid levels decreased the histamine levels in blood and urine rose steadily to maxima in about 10-12 days. The elevated histamine levels persisted in the blood and urine of scorbutic guinea-pigs and the histamine levels in lung, gastric mucosa and spleen also increased. The increased histamine content of the urine, blood and other tissues in the ascorbic-acid-depleted condition could be brought back to normal levels by administration of a single dose of ascorbic acid 5 mg/100 g body wt. guinea-pig. 3. The drop in the elevated histamine level was not due to an indirect effect of ascorbic acid on histamine forming capacity, histaminase activity or histamine release.

Effect of ascorbic acid on histamine metabolism in scorbutic guinea‐pigs.

Effect of ascorbic acid on detoxification of histamine under stress conditions.

Large doses of ascorbic acid had neither beneficial nor toxic effect on growth and maintenance of rats and guinea pigs fed a nutritionally balanced fortified wheat diet. However, a daily intake of 50 mg or more ascorbic acid was toxic to guinea pigs fed unfortified wheat diet. Supplementation of the unfortified wheat diet by casein counteracted the toxicity of large doses of ascorbic acid. J. Nutr. 203: 1688- 1695, 1973.

A. K. Majumder

Papers

Synthesis and some major functions of vitamin C in animals.

Effect of ascorbic acid on histamine metabolism in scorbutic guinea‐pigs.

Effect of ascorbic acid on detoxification of histamine under stress conditions.

Effects of Large Doses of Vitamin C in Guinea Pigs and Rats

Effect of ascorbic acid on detoxification of histamine in rats and guinea pigs under drug treated conditions.