Cellulose is the cellular tissue of plants. It is a member of the carbohydrate family and is allied to starch. In plants, cellulose is normally combined with woody, fatty, or gummy substances. With some exceptions among insects, true cellulose is not found in animal tissues. Microorganisms in the digestive tracts of herbivorous animals break down the cellulose into products that can then be absorbed.
Cellulose is insoluble in all ordinary solvents and may be readily separated from the other constituents of plants. Depending on its concentration, sulphuric acid acts on cellulose to produce glucose, soluble starch, or amyloid; the last is a form of starch used for the coating of parchment paper. When cellulose is treated with an alkali and then exposed to the fumes of carbon disulphide, the solution yields films and threads. Rayon and cellophane are cellulose regenerated from such solutions.
Cellulose acetates are spun into fine filaments for the manufacture of some fabrics and are also used for photographic safety film, as a substitute for glass, for the manufacture of safety glass, and as a moulding material. Cellulose ethers are used in paper sizings, adhesives, soaps, and synthetic resins. With mixtures of nitric and sulphuric acids, cellulose forms a series of flammable and explosive compounds known as cellulose nitrates, or nitrocelluloses. Pyroxylin, also called collodion cotton, is a nitrate used in various lacquers and plastics; another, collodion, is used in medicine, photography, and the manufacture of artificial leather and some lacquers. A third nitrate, guncotton, is a high explosive. Research Cellulose
Nutrition is the strategy adopted by an organism to obtain the chemicals it needs to live, grow, and reproduce. The term is also applied to the science of food, and its effect on human and animal life, health, and disease.
Nutrition involves the study of the basic nutrients required to sustain life, their bio-availability in foods and overall diet, and the effects upon them of cooking and storage. It is also concerned with dietary deficiency diseases. There are six classes of nutrients: water, carbohydrates, proteins, fats, vitamins, and minerals. Water is involved in nearly every body process. Animals and humans will succumb to water deprivation sooner than to starvation. Carbohydrates are composed of carbon, hydrogen and oxygen. The major groups are starches, sugars, and cellulose and related material (or ' roughage'). The prime function of the carbohydrates is to provide energy for the body; they also serve as efficient sources of glucose, which the body requires for brain functioning, utilisation of foods, maintenance of body temperature. Roughage includes the stiff structural materials of vegetables, fruits, and cereal products. Proteins are made up of smaller units, amino acids. The primary function of dietary protein is to provide the amino acids
required for growth and maintenance of body tissues. Both vegetable and animal foods are protein sources. Fats serve as concentrated sources of energy, and protect vital organs such as the kidneys and skeleton. Saturated fats derive primarily from animal sources; unsaturated fats from vegetable sources such as nuts and seeds. Vitamins are essential for normal growth, and are either fat-soluble or water-soluble. Fat-soluble vitamins include A, essential to the maintenance of mucous membranes, particularly the conjunctiva of the eyes; D, important to the absorption of calcium; E, an antioxidant; and K, which aids blood clotting. Water-soluble vitamins are the B complex, essential to metabolic reactions, and C, for maintaining connective tissue and cell functioning. Minerals are vital to normal development; calcium and iron are particularly important as they are required in relatively large amounts. Minerals required by the body in trace amounts include chromium, copper, fluoride, iodine, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, sodium, and zinc. Research Nutrition
Acetohexamide is a medicine used to lower the level of glucose in the blood given to some people with non-insulin-dependent diabetes in pill form. Research Acetohexamide
Aldose reductase inhibitors are a class of drugs believed to prevent eye and nerve damage in people with diabetes. Aldose reductase is an enzyme that is normally present in the eye and in many other parts of the body. It helps change glucose into the sugar alcohol sorbitol. Too much sorbitol trapped in eye and nerve cells can damage these cells, leading to retinopathy and neuropathy. Drugs that prevent or slow the action of aldose reductase are a possible way to prevent or delay these complications of diabetes. Research Aldose Reductase Inhibitor
Cholera is an acute, infectious, often fatal disease caused by the micro organism Vibrio cholerae. It is endemic in India and some other tropical countries and occasionally spreading to temperate climates. The symptoms of cholera are diarrhoea and the loss of water and salts in the stool.
In its more ordinary form it commences with sickness, vomiting, or perhaps two or three loose evacuations of the bowels; after which follow a sense of burning at the praecordia, an increased purging and vomiting of a white or colourless fluid, great prostration of strength, spasms at the extremities, which increase in violence with the vomiting and purging. Such cases may last from twelve to thirty- six hours; after this the patient generally sinks into a state of extreme collapse, and this stage in most cases passes by a gradualtransition into a febrile one, which in a majority of instances proves fatal. Sometimes the patient is suddenly stricken down and dies, collapsed within a few hours without diarrhoea or vomiting.
In severe cholera, the patient develops violent diarrhoea with characteristic 'rice-water stools,' vomiting, thirst, muscle cramps, and sometimes circulatory collapse. Death can occur as quickly as a few hours after the onset of symptoms. The mortality rate is more than 50 percent in untreated cases, but falls to less than 1 percent with proper treatment. Treatment consists mainly of intravenous or oral replacement of fluids and salts. Packets for dilution containing the correct mixture of sodium, potassium, chloride, bicarbonate, and glucose have been made widely available by the WHO. Most patients recover in three to six days. Antibiotics such as tetracyclines, ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole can shorten the duration of the disease, but have their own long term risks in damage to the immune system.
Cholera first appeared (in recognised form) in Europe in 1829, and reached Britain in 1831, spreading thence to America. Western Europe was again visited by it in 1847, 1853, 1865, 1873, 1875, and in 1885. In 1892 Russia and Western Europe suffered severely.
By 1905 it was ascertained that the primary and essential element in the production of cholera was a constituent of the excreta of cholera patients. At the time it wasn't known what the agent was, but that it is an organism capable of propagating itself when it is taken into the alimentarycanal in food, impure water, or the like, was beyond a doubt. Dr. Koch asserted that the essential cause was a bacillus, having the form of a curved rod, hence then called the comma bacillus, and that the disease was caused by the multiplication of this organism in the small intestines.
A method of protective inoculation against cholera was tried in India, with some success around 1900. At the same time it was established that the contagion of cholera is not so likely to be conveyed by personal intercourse as by residence in an infected district. Sanitary measures proved to be the only efficacious means of arresting an epidemic; insanitary conditions decidedly favour it - quite obvious as the disease is spread through contact with infected faeces.
What is called British cholera is a bilious disease, long known in most countries, and is characterized by copious vomiting and purging, with violent griping, cramps of the muscles of the abdomen and lower extremities, and great depression of strength. It is most prevalent at the end of summer or the beginning of autumn. Cholera infantum (infants' cholera) is the name sometimes given to a severe and dangerous diarrhoea to which infants are liable in hot climates or in the hot season. Research Cholera
Gluconeogenesis (glyconeogenesis) is the sequence of metabolic reactions by which glucose is synthesized in the liver, from noncarbohydrate sources, such as amino acids, pyruvic acid, or glycerol. Research Gluconogenesis
Hypoglycemia is a condition characterised by an abnormally low level of sugar in the blood. Symptoms of hypoglycemia include weakness, shakiness, nervousness, anxiety, and faintness and actual fainting. Patients may also show marked personality changes and may seem intoxicated. Hypoglycemia is the result of hyperinsulinism, or an excess of insulin , due either to an overdose of insulin - in the case of persons with diabetes mellitus - or to the body's overproduction of insulin. Insulin is instrumental in regulating carbohydrate metabolism; when hyperinsulinism occurs, glucose is sharply depleted in the process of conversion to glycogen in the liver and muscles and to fat in the adipose tissues. The most common type of hypoglycmia is reactive, or functional hypoglycemia and occurs particularly among persons under emotional stress. It is also due to overproduction of insulin, commonly three to five hours after meals. Its symptoms are milder than those suffered by insulin-dependent diabetics, and it can be controlled by lowering carbohydrate intake. Because reactive hypoglycemia has many of the classical symptoms of depression or anxiety, it is often wrongly believed to be the cause of underlying psychological disorders. Even when this physical condition is properly diagnosed, it is most often found to be incidental to, rather than the direct cause of, the patient's symptoms. Research Hypoglycemia
Insulin is a hormone produced by the pancreas and released into the bloodstream. It promotes the uptake of glucose from the blood by the body cells. A lack of insulin results in glucose being neither consumed as fuel nor adequately stored, but instead the glucose accumulates in the blood until it spills over into the urine. An excess of insulin dangerously decreases the amount of glucose in the blood. Research Insulin
The stomach (fundus) is one of the primary organs of the digestive system. It is located in the middle of the abdominal cavity and extends from the lower end of the esophagus to the duodenum. A curved sac, the stomach has a lesser curvature along the top and a greater curvature along the bottom. The bolus of chewed food paste enters the stomach from the esophagus, propelled by peristaltic waves. The cardiac gastric glands are located near the entrance to the stomach and lubricate the food as it comes in. The stomach secretes hydrochloric acid and the enzymes pepsin, rennin, and lipase which help digest the carbohydrates, proteins and fats in food. The stomach is lined with a durable mucous lining which protects it from the gastric juices so that the stomach itself is not digested. Occasionally, a portion of this lining wears thin and the digestive juices do aggravate the stomach lining. This condition is known as an ulcer and is a frequent occurrence which may affect the stomach, the lower esophagus, or the duodenum. The lower end of the stomach is guarded by the pylorus, a sphincter muscle which admits digested food into the duodenum after it has been adequately processed by the digestive juices.
The average stomach can hold about a liter, but can stretch to hold much more than this. When empty, or nearly empty, the stomach contracts to form folds, or rugae, in its mucous lining. Though it was once thought that the contractions of the stomach in the absence of food was what caused the sensation of hunger, it is now known that the primary impulse of hunger is due to low glucose levels in the bloodstream. However, the contraction of the stomach can often be felt, and this and the 'grumbling' heard as food is passed through the lower digestive tract also serve to remind one of the sensation of hunger. Research Stomach
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Cellulose
