Fatty acids disorders

Zytkovicz TH, Fitzgerald EF, Marsden D, Larson CA, Shih VE, Johnson DM, et al. Tandem mass spectro-metric analysis for amino, organic, and fatty acid disorders in newborn dried blood spots a two-year summary from the New England Newborn Screening Program. Clin Chem 2001 47 1945-55. 

Prostaglandins arise from unsaturated C20 carboxylic acids such as arachidonic acid (see Table 26 1) Mammals cannot biosynthesize arachidonic acid directly They obtain Imoleic acid (Table 26 1) from vegetable oils m their diet and extend the car bon chain of Imoleic acid from 18 to 20 carbons while introducing two more double bonds Lmoleic acid is said to be an essential fatty acid, forming part of the dietary requirement of mammals Animals fed on diets that are deficient m Imoleic acid grow poorly and suffer a number of other disorders some of which are reversed on feed mg them vegetable oils rich m Imoleic acid and other polyunsaturated fatty acids One function of these substances is to provide the raw materials for prostaglandin biosynthesis... 

Inositols, ie, hexaliydrobenzenehexols, are sugars that have received increasing study and are useful in the treatment of a wide variety of human disorders, including vascular disease, cancer, cirrhosis of the Hver, frostbite, and muscular dystrophy (269). Myoinositol esters prepared by reaction with lower fatty acid anhydrides are useful as Hver medicines and nonionic surfactants the aluminum and ammonium salts of inositol hexasulfate are useful anticancer agents (270). Tetraarjloxybenzoquinones are intermediates in the preparation of dioxazine dyes (266,271). The synthesis of hexakis(aryloxy)benzenes has also beenpubUshed (272). 

Patterns of ordered molecular islands surrounded by disordered molecules are common in Langmuir layers, where even in zero surface pressure molecules self-organize at the air—water interface. The difference between the two systems is that in SAMs of trichlorosilanes the island is comprised of polymerized surfactants, and therefore the mobihty of individual molecules is restricted. This lack of mobihty is probably the principal reason why SAMs of alkyltrichlorosilanes are less ordered than, for example, fatty acids on AgO, or thiols on gold. The coupling of polymerization and surface anchoring is a primary source of the reproducibihty problems. Small differences in water content and in surface Si—OH group concentration may result in a significant difference in monolayer quahty. Alkyl silanes remain, however, ideal materials for surface modification and functionalization apphcations, eg, as adhesion promoters (166—168) and boundary lubricants (169—171). 

Pollitt, R. J., 1995. Disorders of mitochondrial long-chain fatty acid oxidation. Journal of Inherited Metabolic Disease 18 473—490. 

Trans Fatty Acids Are Implicated in Various Disorders... 

The catabolism of leucine, valine, and isoleucine presents many analogies to fatty acid catabolism. Metabolic disorders of branched-chain amino acid catabolism include hypervalinemia, maple syrup urine disease, intermittent branched-chain ketonuria, isovaleric acidemia, and methylmalonic aciduria. 

Cholesterol modifies the fluidity of membranes. At temperatures below the T, it interferes with the interaction of the hydrocarbon tails of fatty acids and thus increases fluidity. At temperatures above the T, , it limits disorder because it is more rigid than the hydrocarbon tails of the fatty acids and cannot move in the membrane to the same extent, thus timiting fluidity. At... 

Niacin (vitamin B3) has broad applications in the treatment of lipid disorders when used at higher doses than those used as a nutritional supplement. Niacin inhibits fatty acid release from adipose tissue and inhibits fatty acid and triglyceride production in liver cells. This results in an increased intracellular degradation of apolipoprotein B, and in turn, a reduction in the number of VLDL particles secreted (Fig. 9-4). The lower VLDL levels and the lower triglyceride content in these particles leads to an overall reduction in LDL cholesterol as well as a decrease in the number of small, dense LDL particles. Niacin also reduces the uptake of HDL-apolipoprotein A1 particles and increases uptake of cholesterol esters by the liver, thus improving the efficiency of reverse cholesterol transport between HDL particles and vascular tissue (Fig. 9-4). Niacin is indicated for patients with elevated triglycerides, low HDL cholesterol, and elevated LDL cholesterol.3... 

Finally, an intriguing possible future therapy arises from a radical idea of Horrobin (2001) that schizophrenia is a nutritional disorder linked to a decreased intake of essential polyunsaturated fatty acids. Recent 31P-MRS studies have shown changes in plasma membrane phospholipids in the neocortex of unmedicated schizophrenics, which would have deleterious consequences on synaptic neurotransmission (Fukuzako, 2001). A clinical trial with the co6 fatty acid derivative ethyleicosa-pentaenoic acid (LAX-101) in patients who had been unresponsive to clozapine, reported that a daily dose of 2g LAX-101 gave a 26% improvement in symptoms over 12 weeks compared with 6% with placebo (Peet and Horrobin, 2001). Maybe in... 

Summary Thalassemias as a group are the most common genetic diseases in the world. Beta thalassemia is an inherited blood disorder in which the body produces an abnormal form of hemoglobin. The disorder results in excessive destruction of red blood cells, which in a severe form manifests as life-shortening anemia shortly after birth. Short-chain fatty acids had previously been shown to be useful in the... 

Refsum s disease is an autosomal recessive peroxisomal disorder characterized by accumulation of phytanic acid and other 3-alkyl-branched fatty acids [55]. Patients develop hypertrophic demyelinative polyneuropathy, retinitis pigmentosa, ichthyosis and deafness. The disorder can be successfully treated by institution of a diet poor in phytanic acid, in conjunction with plasmapheresis to remove circulating phytanic acid. 

Adrenoleukodystrophy is an X-linked dysmyelinative disorder caused by mutations in the ABCD1 gene, which encodes the peroxisomal integral membrane ALD protein, a member of the ATP binding cassette transporter family. These mutations result in impaired clearance of plasma very-long-chain fatty acids. Affected males may present with symmetrical distal axonal polyneuropathy, adrenocortical insufficiency or CNS demyelination, while occasional heterozygous women demonstrate deficits suggestive of multiple sclerosis [56]. Manipulation of dietary fatty acid intake has some minimal therapeutic effect, while bone marrow transplantation has diminished deficits in a few patients. (See in Ch. 41.)... 

Bifunctional protein deficiency. The enzyme defect involves the D-bifunctional protein. This enzyme contains two catalytic sites, one with enoyl-CoA hydratase activity, the other with 3-hydroxyacyl-CoA activity [13]. Defects may involve both catalytic sites or each separately. The severity of clinical manifestations varies from that of a very severe disorder that resembles Zellweger s syndrome clinically and pathologically, to somewhat milder forms. Table 41-6 shows that biochemical abnormalities involve straight chain, branched chain fatty acids and bile acids. Bifunctional deficiency is often misdiagnosed as Zellweger s syndrome. Approximately 15% of patients initially thought to have a PBD have D-bifunctional enzyme deficiency. Differential diagnosis is achieved by the biochemical studies listed in Table 41-7 and by mutation analysis. 

Refsum s disease. This disorder, first described nearly 60 years ago, was recently been shown due to a defect in the enzyme phytanoyl-CoA hydroxylase. Phytanic acid is a 3-methyl fatty acid that because of this methyl group cannot be oxidized directly. It is degraded by a peroxisomal a-oxidation to pristanic acid, a 2-methyl fatty acid which can be degraded by P-oxidation. The principal clinical features of Refsum s disease are progressive polyneuropathy, retinal degeneration, hearing loss, cardiomyopathy and ichthyosis, beginning in late childhood or later. 

A second class of disorders of glycogen and fatty acid metabolism causes progressive weakness 699... 

One class of carbohydrate and fatty acid metabolism disorders is caused by defects in enzymes that function in the brain 703... 

Carnitine deficiency is a clinically useful term describing a diversity of biochemical disorders affecting fatty acid oxidation. Carnitine deficiency may be tissue-specific or generalized. 

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