Alistair G. Paice

Alcoholic myopathy: biochemical mechanisms.

Between one- and two-thirds of all alcohol abusers have impairment of muscle function that may be accompanied by biochemical lesions and/or the presence of a defined myopathy characterised by selective atrophy of Type II fibres. Perturbations in protein metabolism are central to the effects on muscle and account for the reductions in muscle mass and fibre diameter. Ethanol abuse is also associated with abnormalities in carbohydrate (as well as lipid) metabolism in skeletal muscle. Ethanol-mediated insulin resistance is allied with the inhibitory effects of ethanol on insulin-stimulated carbohydrate metabolism. It acutely impairs insulin-stimulated glucose and lipid metabolism, although it is not known whether it has an analogous effect on insulin-stimulated protein synthesis. In alcoholic cirrhosis, insulin resistance occurs with respect to carbohydrate metabolism, although the actions of insulin to suppress protein degradation and stimulate amino acid uptake are unimpaired. In acute alcohol-dosing studies defective rates of protein synthesis occur, particularly in Type II fibre-predominant muscles. The relative amounts of mRNA-encoding contractile proteins do not appear to be adversely affected by chronic alcohol feeding, although subtle changes in muscle protein isoforms may occur. There are also rapid and sustained reductions in total (largely ribosomal) RNA in chronic studies. Loss of RNA appears to be related to increases in the activities of specific muscle RNases in these long-term studies. However, in acute dosing studies (less than 1 day), the reductions in muscle protein synthesis are not due to overt loss of total RNA. These data implicate a role for translational modifications in the initial stages of the myopathy, although changes in transcription and/or protein degradation may also be superimposed. These events have important implications for whole-body metabolism.

Free radicals in alcoholic myopathy: indices of damage and preventive studies

Chronic alcoholic myopathy affects up to two-thirds of all alcohol misusers and is characterized by selective atrophy of Type II (glycolytic, fast-twitch, anaerobic) fibers. In contrast, the Type I fibers (oxidative, slow-twitch, aerobic) are relatively protected. Alcohol increases the concentration of cholesterol hydroperoxides and malondialdehyde-protein adducts, though protein-carbonyl concentration levels do not appear to be overtly increased and may actually decrease in some studies. In alcoholics, plasma concentrations of α-tocopherol may be reduced in myopathic patients. However, α-tocopherol supplementation has failed to prevent either the loss of skeletal muscle protein or the reductions in protein synthesis in alcohol-dosed animals. The evidence for increased oxidative stress in alcohol-exposed skeletal muscle is thus inconsistent. Further work into the role of ROS in alcoholic myopathy is clearly warranted.Chronic alcoholic myopathy affects up to two-thirds of all alcohol misusers and is characterized by selective atrophy of Type II (glycolytic, fast-twitch, anaerobic) fibers. In contrast, the Type I fibers (oxidative, slow-twitch, aerobic) are relatively protected. Alcohol increases the concentration of cholesterol hydroperoxides and malondialdehyde-protein adducts, though protein-carbonyl concentration levels do not appear to be overtly increased and may actually decrease in some studies. In alcoholics, plasma concentrations of alpha-tocopherol may be reduced in myopathic patients. However, alpha-tocopherol supplementation has failed to prevent either the loss of skeletal muscle protein or the reductions in protein synthesis in alcohol-dosed animals. The evidence for increased oxidative stress in alcohol-exposed skeletal muscle is thus inconsistent. Further work into the role of ROS in alcoholic myopathy is clearly warranted.

Serial review: alcohol, oxidative stress, and cell injuryFree radicals in alcoholic myopathy: indices of damage and preventive studies1

Chronic alcoholic myopathy affects up to two-thirds of all alcohol misusers and is characterized by selective atrophy of Type II (glycolytic, fast-twitch, anaerobic) fibers. In contrast, the Type I fibers (oxidative, slow-twitch, aerobic) are relatively protected. Alcohol increases the concentration of cholesterol hydroperoxides and malondialdehyde-protein adducts, though protein-carbonyl concentration levels do not appear to be overtly increased and may actually decrease in some studies. In alcoholics, plasma concentrations of α-tocopherol may be reduced in myopathic patients. However, α-tocopherol supplementation has failed to prevent either the loss of skeletal muscle protein or the reductions in protein synthesis in alcohol-dosed animals. The evidence for increased oxidative stress in alcohol-exposed skeletal muscle is thus inconsistent. Further work into the role of ROS in alcoholic myopathy is clearly warranted.Chronic alcoholic myopathy affects up to two-thirds of all alcohol misusers and is characterized by selective atrophy of Type II (glycolytic, fast-twitch, anaerobic) fibers. In contrast, the Type I fibers (oxidative, slow-twitch, aerobic) are relatively protected. Alcohol increases the concentration of cholesterol hydroperoxides and malondialdehyde-protein adducts, though protein-carbonyl concentration levels do not appear to be overtly increased and may actually decrease in some studies. In alcoholics, plasma concentrations of alpha-tocopherol may be reduced in myopathic patients. However, alpha-tocopherol supplementation has failed to prevent either the loss of skeletal muscle protein or the reductions in protein synthesis in alcohol-dosed animals. The evidence for increased oxidative stress in alcohol-exposed skeletal muscle is thus inconsistent. Further work into the role of ROS in alcoholic myopathy is clearly warranted.

Influence of the Crushing System: Phenol Content in Virgin Olive Oil Produced from Whole and De-stoned Pastes

Publisher Summary The mechanical processes used to extract virgin olive oil from olive fruit include the crushing of the olives, malaxation of resulting pastes and separation of the oily phase essentially by pressure or centrifugation. All these operations affect the quality of virgin olive oil. Olive paste preparation is the most important phase of the process when oil is mechanically extracted from the olives. The use of differing machines in olive oil production has inevitable repercussions on the cost-effectiveness of the oil-making process, on the amounts of oil extracted and especially on the quality of the oil obtained. In order to obtain the best virgin olive oil, quality olives must be processed as quickly as possible after harvesting from the trees. Normally they should be delivered to the mill within a day or so of picking, in order to keep down oxidation and acidity. When extracting oil from olives, it is very important to clean them properly first, in order to ensure the levels of hygiene required for a high-quality olive oil product. Once cleaned, the olives must be crushed, in order to make the olive paste that itself is the first stage in extracting the oil. How this is done is crucial for both the quantity and the quality of the olive oil product. Mechanical oil extraction from de-stoned pastes can improve the oil phenolic concentration. The quality characteristics of virgin olive oil also depend on oxidative enzyme reactions that take place in olive paste during the extraction process. Two enzymes, polyphenol oxidase (PPO) and peroxidase (POD), are highly concentrated in the olive kernel. PPO and POD can oxidize phenolic compounds resulting in a reduced phenolic concentration of oil. The de-stoning process, excluding the olive seed before malaxation, partially removes the peroxidase activity in the pastes. This results in an increase in oxidative stability and nutritional value of virgin olive oil.

Ca2+-regulatory muscle proteins in the alcohol-fed rat☆

Alcoholic myopathy is characterized by muscle weakness and difficulties in gait and locomotion. It is one of the most prevalent skeletal muscle disorders in the Western hemisphere, affecting between 40% and 60% of all chronic alcohol misusers. However, the pathogenic mechanisms are unknown, although recent studies have suggested that membrane defects occur as a consequence of chronic alcohol exposure. It was our hypothesis that alcohol ingestion perturbs membrane-located proteins associated with intracellular signalling and contractility, in particular those relating to calcium homeostasis. To test this, we fed male Wistar rats nutritionally complete liquid diets containing ethanol as 35% of total dietary energy. Controls were pair-fed identical amounts of the same diet in which ethanol was replaced by isocaloric glucose. At the end of 6 weeks, rats were killed and skeletal muscles dissected. These were used to determine important ion-regulatory skeletal muscle proteins including sarcalumenin (SAR), sarcoplasmic-endoplasmic reticulum Ca(2+)-adenosine triphosphatase (ATPase) (SERCA1), the junctional face protein of 90 kd (90-JFP), alpha(1)- and alpha(2)-dihydropyridine receptor (alpha(1)-DHPR and alpha(2)-DHPR), and calsequestrin (CSQ) by immunoblotting. The relative abundance of microsomal proteins was determined by immunoblotting using the enhanced chemiluminescence (ECL) technique. The data showed that alcohol-feeding significantly reduced gastrocnemius and hind limb muscle weights (P <.05 in both instances). Concomitant changes included increases in the relative amounts of SERCA1 (P <.05) and Ca(2+)-ATPase activity (P <.025). However, there were no statistically significant changes in either SAR, 90-JFP, alpha(1)-DHPR or alpha(2)-DHPR (P >.2 in all instances). Reductions in CSQ were of marginal significance (P =.0950). We conclude that upregulation of SERCA1 protein and Ca(2+)-ATPase activity may be an adaptive mechanism and/or a contributory process in the pathology of alcohol-induced muscle disease.

The Malaxation Process: Influence on Olive Oil Quality and the Effect of the Control of Oxygen Concentration in Virgin Olive Oil

Publisher Summary Malaxing is an extremely important phase in olive oil extraction. During the malaxing phase the olive paste is subjected to a slow continuous kneading, aimed at breaking off the emulsions formed during the crushing process and facilitating adequate coalescence. It is necessary to heat the olive paste at a carefully monitored temperature during malaxation in order to diminish the viscosity of the product and to stimulate its enzymic activity, therefore increasing the extraction yields. This operation facilitates high extraction yields, by helping small oil droplets to coalesce. These can be separated subsequently using a decanter centrifuge. The malaxing process determines the balance between the quality and the quantity of the oil extracted, by varying a range of parameters (time, temperature, and atmosphere in contact with the olive paste), as the olive paste is gradually heated and the enzymes within are activated. All this must be done without affecting the biochemical structure of the olive paste, as this would affect the flavor, shelf-life and nutritional properties of the oil. This operation is one of the critical points in olive oil extraction. Many studies have been carried out to investigate its influence on the olive oil quality. Nowadays the olive oil consumer asks for healthy products. There has been a large increase in demand for high-quality virgin olive oil, attributed not only to its potential health benefits, but also to its particular organoleptic properties. In fact, the sensory quality plays an important role in customer preferences. The operating environment during malaxation affects the volatile and phenolic composition of virgin olive oil and, as a consequence, its sensory and healthy qualities.

Bambara Groundnut [ Vigna subterranea (L.) Verdc. (Fabaceae)] Usage in Human Health

Publisher Summary This chapter presents a report on bambara groundnut seed utilization in human health. The plant has a significant impact on human nutrition by improving the quality of nutrition and, consequently, the health of many rural communities. BG produces a food of exceptional nutritional quality and thus plays an important role in building and maintaining a solid foundation for good health. The seeds have a good nutrient balance and are a rare example of a complete food. They contain sufficient quantities of proteins, carbohydrates, and lipids to sustain human life. Seed proteins also contain more of the essential amino acid methionine than almost any other bean. Another broad category of health benefit exhibited by the plant is its use in traditional medicine therapies. Seeds are used by the Igbos tribe in Nigeria to treat venereal diseases, and, according to the Luo tribe in Kenya, seeds are also used to overcome diarrhea. The consumption of roasted seeds is recommended in the treatment of polymenorrhea. Among the beans, bambara groundnut seeds have the highest concentration of soluble fiber. They are a non-nutrient believed to reduce the incidence of heart disease and to help prevent colon cancer. The chewing and swallowing of immature fresh seeds is supposed to arrest nausea and vomiting; this remedy is often used to treat morning sickness in pregnant women. Bambara groundnut seeds have also been used to treat some malignancies and inflammatory disorders in Africa. Pharmacological studies needed to confirm these ethno-botanical reports remain to be performed. Currently, no detailed biochemical studies have been published on the toxicity and potential adverse effects associated with the medicinal usage of bambara groundnuts.

Black Soybean (Glycine max L. Merril) Seeds’ Antioxidant Capacity

Publisher Summary This chapter describes the black soybean as a plant and a source of food products and illustrates the activity of its extract and subsequent food products in preventing diseases and promoting health. Black soybean has been used as a health-food ingredient and herb in China for centuries. Recently, studies on the biological activities of the black soybean have increased significantly, especially in the investigation of its anthocyanin content. Anthocyanin is a bioactive compound found in the seed coat of the black soybean that is reported to inhibit several diseases due to its inherent antioxidant activity. In food systems, antioxidants can help prevent undesirable flavors and nutritional degradation. In the human body, antioxidants are believed to play an important role in the inhibition of several degenerative diseases, such as cancer, coronary heart disease, atherosclerosis, and diabetes. Black soybean seed coats, on the other hand, are rich in phenolic substances, in which secondary metabolites from plants are biologically active as antioxidants. The seed coat contains anthocyanins, which is a water-soluble pigment responsible for the black, red, and blue color of the plants, and is well known as having considerable pharmaceutical activity. The beneficial properties of black soybean may be linked to its ability to prevent LDL oxidation. In the human body, LDL is a transport mechanism for cholesterol. Oxidized LDL is thought to play a central role in the development of atherosclerosis, leading to diseases such as coronary heart disease. Despite its beneficial properties, black soybean contains potential allergenic and toxic components. However, adverse effects following soy consumption are rare and depend on the individual.

Use of Seeds of Malay Apple ( Ziziphus mauritiana ) and Related Species in Health and Disease

Publisher Summary This chapter examines the potent health-beneficial properties of the seeds of the Malay apple. As a rich source of many compounds like ascorbic acid, riboflavin, alkaloids, glycoside, saponins, and triterpenoic acid, the malay apple is used in the prevention and cure of many diseases. The seeds of Ziziphus species possess anxiolytic and sedative activities. In vitro studies have demonstrated that the oleamide component of the Ziziphus jujube seed extract may help patients suffering from Alzheimers disease. They are also known to suppress the central nervous system, resulting in reduced anxiety and the induction of sleep. The flavonoids, saponins, and alkaloids present in seeds can also be used for sedation. Seed extract may also have applications in the treatment of tuberculosis, cancer, and AIDS, as alterations to TH-1-mediated immunity are implicated in these diseases. Ziziphus seeds are also rich in saponins, known to bind cholesterol. These compounds are widely used for cholesterol control. It contains the valuable phytocompound betulinic acid, which may be useful in new drug designs. This adaptable plant has a wide range of potential economic roles, such as bee-keeping, fodder, or fuel.