CARBOHYDRATES

From Big Medical Encyclopedia

CARBOHYDRATES (synonym: glitsida, glyu-tsida, saccharites, sugar) — the extensive, most extended on Earth class of the organic compounds which are a part of all organisms and necessary for life activity of the person and animals, plants and microorganisms. At. are primary products of photosynthesis (see), (see) in the nature they serve as a peculiar bridge between inorganic and organic compounds in a circulation of carbon. At. and their derivatives in all living cells carry out a role of plastic and structural material, the supplier of energy, substrates and regulators for specific biochemical processes. Contents various At. in blood, urine and others biol. liquids of the person is an informative diagnostic character of the disturbances of carbohydrate metabolism (see) having hereditary character or which developed for the second time as result various patol. states. In food of the person At. are one of basic groups of substances along with proteins (see) and fats (see).

The term «carbohydrates» (carbon - (-water) was offered in 1844 by Schmidt

(S. to Schmidt) since formulas of representatives of this class of substances famous at that time corresponded to the general formula of the Joint venture (H20) of t. However it turned out later that the similar formula can be had not only At., and napr, milk to - that, besides, to At. began to carry their derivatives, various, similar on properties, with other general formula which are formed at introduction to a molecule U. the deputies containing nitrogen, sulfur or phosphorus, and also products of their oxidation or recovery.

The mankind used At. also he was familiar with their transformations from an extreme antiquity. One of the first emitted purely organic matters (see. Organic compounds) were At., they before other connections were subjected to acid and enzymic hydrolysis, fermentation (see Fermentation), were synthesized by one of the first in the chemical way. Research of chemical properties and transformations At. went parallel to development and achievements of organic chemistry (see) and biochemistry (see). A big contribution to studying of a structure and chemistry At. A. M. Butlerov, Kiliani brought (Ii. Kiliani), E. Fischer, W. N. Haworth, etc.

Class U. includes connections, very different on type, beginning from the low-molecular substances containing only several carbon atoms and finishing connections with repeatedly branched carbon chains and with huge a pier. it is powerful (weight), reaching several million dalton. At. conditionally divide into three big groups: monosaccharides (see), oligosaccharides (see) and polysaccharides (see). Separately the group of conjugate biopolymers is considered, molecules to-rykh contain along with an oligo-sakharidny or polisakharidny chain proteinaceous (see Glycoproteins), lipidic (see Glycolipids) and other components.

Carry polyhydroxy aldehydes (aldoses) and polyhydroxy-ketones (ketosis) to monosaccharides (monoses). On number of carbon atoms monosaccharides divide into trioses, tetroses, pentoses, hexoses, heptoses, octoses, nonoza. Are most widespread in the nature and also pentoses are important for the person of hexose (see) (see). On a relative positioning of hydrogen and hydroxylic group (IT is groups) at the last asymmetric carbon atom all monosaccharides carry to D-or a L-row (see the Isomerism). The free monosaccharides and monosaccharides, widespread in the nature, which are a part of numerous connections belong hl. obr. to a D-row. In solid state monosaccharides are in a type of inner hemiacetals — ■ nyatichlen-ny (faugh rapoz) and six chlenny (pyranoses). In r-re monosaccharides, except their cyclic forms, there are most a rea to i a tsyunno-way-nye, acyclic forms. Treat monosaccharides also deoxysugar, one or two hydroxylic groups in a molecule to-rykh are replaced with hydrogen, an amiiosakhara (see), the hydroxylic group in a molecule to-rykh is replaced and to a minogr of 111 ioii, geksuro new acids, (see) and others uranium to and ate about i p y (with m), of i e r in and h N and I with and and r t about in and I group in a molecule to-rykh am oxidized in carboxyl, aldonic to - you, the carbonyl group in a molecule to-rykh is oxidized in carboxyl, double-base sugar to - you, polyatomic alcohol of an aldita, simple and esters of monosaccharides glycosides (see), sialic acids (see) etc.

Refer connections to oligosaccharides. molecules to-rykh are constructed of the remains of cyclic forms of the monosaccharides connected by Au - a glycoside-nymi by bonds to a .mezhd hemiacetal or between noluatsetalny and spirit gidroksily1ymi groups in reaction with eliminating of water, and chis lo the remains of monosaccharides in molecules of oligosaccharides does not exceed 10. Oligosaccharides divide into di - three - tetrasakharida etc. on number of the remains of monosaccharides entering them. If the molecule of oligosaccharide is constructed of the remains of the same monosaccharide, then such oligosaccharide is called gomooligosakharidy if such molecule is constructed of the remains of different monosaccharides — geterooligo-Sakha Read. About l of an igos ha rida happen linear. cyclic, branched, reducing and nere-du feasting (depending on that, the carbonyl group is free or engaged in any rest of a monosaccharide), oligosaccharides distinguish also on bonding between the remains of monosaccharides. Sometimes monosaccharides and oligosaccharides combine under the general name of «sugar». In glycosides (gete-rozid) a monosakharidny or oli-gosakharidny part of a molecule can be connected to npzkomolekulyar-ny substance of not carbohydrate nature (aglikony) through sulfur, oxygen or nitrogen.

Polysaccharides (a floor of a pose, glycanes) represent vysokomo-lekul the yarny products of a jyulikondensa-tion of monosaccharides sometimes containing tens and hundreds of thousands of remains of the monosaccharides connected by gliko-zpdny bonds. The 33rd structure poly-sakharidoi the remains sulfuric, phosphoric and fat to - t can enter. There is a group of the polysaccharides constructed by means of phosphodiester bonds. Polysaccharides divide on gomo-and heteropolysaccharides depending on that, their molecules are constructed of the remains of monosaccharides of one view or from the remains of various monosaccharides, and also on linear and branched; polysaccharides are distinguished also on ooze of communication between the monosakharidny remains. Oligosaccharides and polysaccharides, at full hydrolysis to-rykh are formed only monosaccharides, often call just saccharites.

Uglevodsoderzhashchy conjugate biopolymers (glycoconjugates) carry out very important biol. functions, however their classification it is finally not developed. Among gln-kokonjyugat distinguish gliko! gro-teida (contain peptide and polisakharidny or oligosakharidny chains), glycolipids (are constructed of io-l is and ha r and d by N y x silt and about l and state and x and r go y x chains and a lipidic component), glikoliioproteida (contain carbohydrate, lipidic and proteinaceous components), teykhoyevy to - you (in their molecules amino acids and monosaccharides are attached to a chain from the remains of spirit derivatives iolioz — polyalcohols), nucleic acids (see). The ratio of various components in molecules of the separate mixed uglevodsoderzhashchy biopolymers .mozht to fluctuate over a wide range.

Properties of oligosaccharides and polysaccharides are defined first of all by properties of their monomer units therefore studying of chemical behavior, dependences between structure and fnz. chemical and biol. properties U., and also ways of modification of these properties by structural change of a molecule first of all it is connected with development of chemistry of monosaccharides. Many monosaccharides have sweet taste, represent nonvolatile, easily water soluble and other polar solvents of substance and not a rastvorima in non-polar solvents that is caused by existence in their molecules of a large number of hydroxylic groups. In water solution monosaccharides are capable to mutarotation (see), many of them easily crystallize, but mutarotation slows down this process. All monosaccharides are optically active connections and have the recovering (reducing) ability. Atsiklig-chesky monosaccharides are capable to recovery with formation of poly-alcohols, or on l of yoles, to oxidation with education uranium, and ldonovy and sugar to - t. At impact on monosaccharides to - t or alkalis at first there is an epimeriza-tion and interconversion of an aldosa-har in ketosugar and back. In more rigid conditions under action to - the t from monosaccharides are formed furfurals (see), and under the influence of alkalis in molecules of monosaccharides there is a gap carbon — carbon bonds. At. with free carbonyl group react, characteristic of aldehydes (see), form hydrazones, osazones and their substitution derivates. Formation of glycosides happens at the expense of noluatsetalny hydroxylic group U.; alkylation, acyl to an irovaipa ari-lprovat not, formation of ethers inorganic to - t — at the expense of spirit hydroxylic groups.

Polysaccharides, as a rule, are amorphous substances, low solubility or water-insoluble and various organic solvents, not capable to crystallization (see). Water soluble polysaccharides form colloids (see), insoluble — bulk up (see Swelling). Polysaccharides have practically no reducing power.

Oligosaccharides on the properties are intermediate between monosaccharides and polysaccharides, they are rastvorima in water, crystallize, many have sweet taste. Oligosaccharides and polysaccharides under action to - t are hydrolyzed to monosaccharides, and iod effect of alkalis occurs so-called alkaline degradation as about l a yoke - and polysaccharides.

Commercially At. receive hl. obr. from natural sources, since in the nature At. are widespread very widely. However from monosaccharides in a stand-at-ease in natural sources D-glucose and D-fructose are found generally, other monosaccharides in a free look meet much less often; they, as a rule, are a part of extremely various natural oligosaccharides, polysaccharides, glycosides and the mixed uglevodsoderzhashchy biopolymers (glycoconjugates). In plants up to 70 — 80% of dry weight it is the share of

U. V bodies and tissues of the person and animals no more than 2% contain At. on the dry weight of fabric, generally it is a glycogen of a liver and muscles. At. food — sucrose, lactose, starch, dextrins — are exposed in

about r to of a h and z me r and z l ichn y m and p e in r and shche and iya m with formation of glucose (see), edges is the main sugar of blood, forms a glycogen of fabrics and along with a galactose (see), glyukozazhiny (see) and to galactoses other is a part of glycoconjugates. Glucose is necessary in an organism not only as the main source of energy, but also as the predecessor of pentoses, uranium to - t and phosphoric ethers of hexoses. In blood of the healthy adult its concentration normal makes 50 — 95 mg! 100 ml; except it, are found in blood of the person fructose (0,5 — 5 l of / 100 ml), pentoses (1,8 — 3,3 m of/YuO of ml), traces of a galactose (see), maipoza (see), lactoses (see), maltoses (see), sucrose (see), a glycogen (see) in concentration of 7 — 15 mg! 100 ml. At children the maintenance of a glycogen in blood reaches

20 laid down / 100 ml. Cerebrospinal liquid normal contains 40-THAT mg! 100 ml of sugars, i.e. 2/3 —:3/4 amounts of the sugars which are contained in blood. With urine of the adult healthy person in days 16 — 132 mg of glucose are allocated, in urine traces of xylose (see), pectine sugars, riboses (see), rhamnoses, fructose, lactoses, sucrose, a glyu-kuronlaktona, etc. are found. At the child at food milk the content of lactose in urine can increase to 35 mg / 100 ml, in the first 10 days of life of the child contain in his urine lactose (120 mg! 100 ml), fructose (70 mg! 100 ml), glucose and a galactose (on 25 mg! 100 ml). at premature children these indicators are higher. Normal with urine at adults 65,8 — 193,4 mg of mukopro-teid (see Mukoproteida) and 2,7 — 7,5 mg of acid glikozaminoglikan are allocated per day (hondroitinsulfat And yes C), the daily amount of urine contains

1 — 11 mg! 100 ml of glycoproteins.

Studying biol. properties U., their functions in biochemical systems it is necessary for knowledge of a being of the major processes of life activity and it is directly connected with progress of biochemistry and molecular biology (see). A role At. it is not limited to the reserve functions consisting in a covering of continuous power consumption in the course of life activity, silt and the structural and basic function characteristic napr for cellulose (see) or chitin (see). It was proved that the photosynthesis providing synthesis of organic matters on Earth is generally process of transformation fosforilirovanny sa ha a ditch. H a cut-vychayno highly specialized functions U are important.: N-glikozi-

dy, nucleotides coenzymes and redoxons and B15 play an exclusive role in all parties of a metabolism and energy; highly active anticoagulant is polysaccharide heparin (see); hyaluronic to also ate t y (see) interfere with penetration of microorganisms into fabrics, participate in process of fertilization, etc. In medicine the group of the antibiotics, by the chemical nature which are glycosides is widely used; specific l and p about p ol and saccharites (see) microorganisms have pronounced antigenic properties that formed a basis for their use in medical practice as so-called chemical vaccines (see). Similar vaccines from

pneumococci (see), meningokokk (with m of M e N and and about coccal and and fekts and I),

Haemophilus influenzae (see Gemo-globinofilpye of a bacterium), etc. have high performance. Specificity of blood groups (see) and t to and N e y about at with l about in l e N and r at p have a sleep c and f and - accurate substances (see), to-rye by the nature are the uglevodso-holding connections. Marker function. At. in glycoproteins provides interaction of various biologically active agents with the corresponding receptors. Glycolipids gangliosides play an important role in carrying out nervous impulses and are necessary for normal implementation of functions of century and. In processes of exchange At., there are intermediate products, to-rye are used for synthesis of various not carbohydrate connections. At plants by such way phenols (see), organic to - you, tanning agents (see Tannins), amino acids (see), proteins, fats, etc. are synthesized; at the person and animals at glycolysis biosynthetic predecessors of lipids, and in a pentozofosfatny way — predecessors nucleinic to - t etc. are formed.

At disturbance of exchange any At. its concentration in biol. liquids changes; registration of these changes plays an important role in establishment of the diagnosis. So, at diagnosis of a diabetes mellitus (see a diabetes mellitus) definition in blood and urine of concentration of glucose is one of the main diagnostic tests. Different types of meliturias (see) — a galaktozuriya, a fruktozuriya, a sakharozuriya, iyento-zuriya, etc. — diagnose on existence in urine of the corresponding sugars. At glycogenoses (see) concentration of a glycogen in blood increases to 100 mg! 100 ml and above, observe decrease in concentration of a glycogen in blood at acute hepatitises (see Hepatitis). At meningitis (see) in cerebrospinal liquid note reduction of concentration of glucose (gipoglikorakhiya), and at encephalitis (see) and a diabetes mellitus — increase in concentration of glucose (hyperglycorrhachia). At genetically caused disturbances of exchange of glikozaminoglikan — mukopolisakharidoza (see) in urine of patients concentration of acid mucopolysaccharides increases (see); at a gargoilizm and Gunter's syndrome (see Gargoilizm) — a hondroitinsulfata In and a geparitinsulfata, at Sanfilippo's syndrome (see. With anfilippo a disease) — a geparitinsulfata, at Morkio's syndrome (see Morkio a disease) — a keratin ulfa-that and a hondroitinsulfata And. at Sheye's syndrome (see Sheye a disease) — a hondroitinsulfata In, etc.

Methods of definition of carbohydrates.

At disturbances of carbohydrate metabolism (see) the content of separate sugars usually define in the most available material — urine and blood of the patient. According to the destination methods of definition At. it is possible to divide into qualitative tests, quantitative methods, methods of identification of sugars and the ress-methods of definition of sugars which are intensively developing in the last decades on l at a stake ichestvenn yo e ks p with use of ready forms of reactants (tablets, paper strips, so-called test pieces of paper, etc.).

In urine healthy to Luda]! trace amounts of glucose and other sugars contain, to find to-rye usual reactions very difficult. However at a number of disturbances of carbohydrate metabolism, at damages of kidneys and nek-ry the friendtheir diseases concentration of sugars in urine can sharply increase, and this increase can be found by means of qualitative tests on sugar. The majority of tests is based on ability of glucose and other monosaccharides at oxidation to recover a number of substances. In tests of T rum a measure, Felinga, Gaynesa, Benedict (see Benedict methods) p other glucose during the heating in alkaline condition recovers the hydrate of SI copper oxide (ON) 2 of blue color which is formed in the course of definition of CuS04 copper sulfate and NaOH caustic soda in hydrate of IT SI cuprous oxide of yellow color and Sn20 cuprous oxide of red color. Test is considered positive at decolourization from blue till yellow-red color. Interferes with conducting test surplus of copper ions since at the same time the black deposit oksp <and SIO copper is formed. For removal of surplus of m ■ I add to a reactant of Felinga! to an eegpetov salt (vinnoktic, 1 yp h-i' — sodium), in a reactant Gapn< i • glycerin, in a reactant Bepedim ■ sodium citrate. In test Nilap. “ra (see Nilander test) in Kacha *' 1 not recovered substance and with use bismuth nitrate, to-ry turns into brown bismuth oxide, and then into black metal bismuth. All tests based on recovery easily can be carried out in any laboratory, do not demand the special equipment, () d N and to about it 11 with t of p i i yes to> t with at shch (1 with t in e and and y m of t \shortcomings:

it is impossible to define amount of sugar by such tests and they are nesletsifichna since substances of m answer in the affirmative not only with sugars, but also with any and, about l and d and yu shch and m and in wasps with that a pas and l and - the howling properties. Therefore qualitative ii of a uniform on sugar find practical application in clinicodiagnostic and the more so in biochemical laboratories more and more seldom.

Quantitative methods of definition of sugars in biol. liquids are very different. The most important of them are polarimetric (see

II Olya R and meter iya), titrimetric

(see. The titrimetric analysis),

different types of colorimetric methods (see Colorimetry) and enzymatic methods. In molecules of glucose and other sugars there are asymmetric carbon atoms therefore solutions of these sugars can rotate the plane of the polarized ray of light. The angle of rotation is proportional to concentration of sugar, defining an angle of rotation, naira, test of urine, in the polarimeter, it is possible to determine the content of glucose in urine. However the direction and size of specific rotation of various sugars significantly differ from each other, and presence at urine of several sugars or other optically active substances brings a big mistake in definition of glucose. For polarimetric definition of sugars urine needs to be exempted from impurity of other sugars previously; urine, in a cut determine glucose by a polarimetric method, shall be transparent and colourless.

Titrimetric methods of definition of glucose are based on reducing power of sugars (so-called reduktometrichesky methods). During the definition of concentration of glucose by the Hagedor-na method — Janszen blood proteins besiege zinc hydroxide, and glucose of a protein-free filtrate in alkaline condition recovers red blood salt to yellow blood salt. Excess of red blood salt is measured by yodometrichesky titration and thus establish concentration of glucose. This method was applied earlier widely and the wedge, laboratories continues to be applied in separate, however it should be noted that it nesiyetsifichen concerning glucose since together with it all substances having the recovering properties are determined by Hagedorn's method — Janszen. Modification of this method is Fujita's method — Ivatake when blood proteins besiege cadmium sulfate, to-ry together with proteins besieges the nek-ry substances having the recovering properties: uric acid (see), glutathione (see) etc. Nevertheless all titrimetric methods of definition of glucose are not specific, they are labor-consuming and demand a lot of time for performance that complicates their use at mass inspections, medical examinations, etc.

The first attempts to simplify quantitative methods of definition of sugars were made in an otnosha

of scientific research institute redukto metric methods, to-rye were modified in colorimetric. Kretselius's method — Zeyferta is based on recovery in alkaline condition picric to - you under the influence of glucose to a brown-red p and to r and m in about in about y

to - you, intensity of coloring a cut is measured by a kolorimetrirovaniye. However this method was very inexact (the error of definition made 20 — 30%). More perfect of this group of methods Nelson method — Shomodyi when copper from a copper and hydroxy-malonic reactant is exposed to recovery is considered; the formed protoxidic hydroxide of copper with arsenomolibdaty ammonium gives a molybdenic blue, intensity of coloring a cut define colorimetric. The further attempt to simplify quantitative methods of definition of sugars can be tracked on the example of the Alt-gauzena method and its modification (see Aljtgauzen a method). The recovering sugar in solution during the heating with alkali is exposed wasps to a prayer, at the same time coloring from various tones of red color to brown develops; comparing this coloring to a color standard scale, it is possible to define approximately a sugar content in urine or other liquid. However Altgau-zen's method, as well as his modifications, is inexact and nesiyetsifichen.

At careful heating of monosaccharides with mineral to-tami there is their dehydration and turning into faugh r faugh beaters (see). The last in acid medium can form colored compounds with various cyclic substances (and - naphthol, Anteronum, L-tryptophane, phenol, etc.). In a wedge, and biochemical laboratories in 50 — the 60th 20 century the colorimetric antronovy method of definition of glucose in blood after removal of proteins (Morris's method and his modifications) based on this principle was widespread. Intensity of the developed blue coloring was measured on a photometer (see Photometry), and the summary contents of sugars in blood was determined by a standard curve. In such methods special attention should be paid to strict observance of a temperature schedule of reaction.

Aldosugar during the heating in the subacidic environment are capable to be condensed with arylamines (aniline, biphenyl amine, au tolite-idinom, etc.) and to form the painted products. This their property was used for development of methods of definition of aldoses. In our country the method of definition of glucose in urine and in blood by means of au - tolui-dyne is unified (see. Orthotoluidne test). This method is more specific concerning aldosugars, than reduktometrichesky and antronovy methods.

However the methods based on use of pure enzymes have the highest specificity. Glucose in urine and in blood determine of the hatch zoo ks and yes zn ym by method by enzyme of glucose oxydas (see Gorodetsky methods). Glucose under the influence of this enzyme turns in gluconic to - that, and in reaction hydrogen peroxide is formed, to-ruyu split iyerok-sidazy, and the emitted elemental oxygen oxidizes a leykoforma of any dye (about - toluidi - on, au dianisidine, etc.) in his painted form. Intensity of the developed coloring is proportional to the content of glucose, the amount of glucose is determined by a standard curve. Attempts to define glucose by enzyme of a hexokinase (see) were carried out. In reaction glyukozo-6-phosphate and ADF, contents glyukozo - 6 - phospha are formed - that define with the help glyukozo-

6-fosfatdegidrogenaza (the so-called two-level UF-test of Warburg) or define the maintenance of ADF by a pyruvatekinase and a lactate dehydrogenase (the three-stage UF-test of Warburg). Hexokinase methods are exact, specific, but are a little applied because of absence and high cost of pure fermental drugs. With receiving pure fermental drug of a galaktozooksi-daza the specific galaktozooksidazny method of definition of a galactose in biol was developed. liquids with use of this enzyme, similar to glyukozooksidazny. Further development and modification of enzymatic methods is very perspective since their use gives the chance precisely, quickly and is specific to determine the content of each sugar in biol. liquids. Many quantitative methods of definition of sugars (reduktometrichesky, o-toluidine, glyukozo-oksidazny) were modified for autoanalyzers (see the Car analyzers) therefore clinics had an opportunity to carry out within a short period of time and with the minimum expenses serial definitions of concentration of sugars in blood, urine, etc.

Attempts to identify sugar in urine and blood were undertaken long ago, special need for use of methods of identification arose in connection with diagnosis of various meliturias and diseases of accumulation (see of a likozidoza, t. 10, additional materials), research of oligosaccharides of urine, etc. Earlier often applied a research to identification of sugars of urine easily about -

razuyushchikhsya ozazonovy and gidrazo new crystals of sugars, to-rye strongly differ not only but to outward, but also on properties. Tried to apply fermentation of sugars different types of bacteria (e.g., Monilia, etc.). Were developed and were applied in clinic of test on separate types of sugars, the majority from to-rykh was based on formation of furfurals. Pentoses found by means of phloroglucinol test of Tollens, ortsinovy test of Bial, a benzidine test of Tauber, etc.; fructose — by means of Selivanov's test with resorcin (see Selivanov test) and a resorcinol method of Rowe (the method is based on transformation of fructose in the presence of the concentrated chamois or salt to - you in the oxymethylfurfural forming with resorcin red-brown coloring, intensity to-rogo are proportional to amount of fructose), Bang's test, methods with R-indolil-uksusnoy and thiobarbituric to-tami; the galactose and lactose were found mucic acid by training (see) in Kolmer's test — Bernera (test is based that a galactose in the presence of nitric to - you are oxidized to mucic to - you, edges drops out in the form of a white deposit); sucrose — on acid or enzymic hydrolysis and change of an angle of rotation of the polarized light, increase in reducing power or emergence of free glucose. However to characterize all composition of sugars in the studied test became possible only during the use of electrophoretic division of borate complexes of sugars (see the Electrophoresis) or different types of a chromatography (see) — on paper, in a thin coat of silica gel, columnar and a gas liquid chromatography. At the same time, applying various systems of solvents and different developers, it is possible to define authentically qualitative composition of sugars in test, to measure amount of each sugar and even to allocate it preparativno for the further analysis and identification. By the most perspective, exact and reliable method of identification and definition of sugars in biol. substrates the method gas and a gas liquid chromatography is.

At identification of oligosaccharides it is necessary to define their monomeric structure, a polymerization degree and types of bonds. During the definition of polysaccharides (e.g., a glycogen) by the method offered M. E. Preobrazhenskoy who is quantitatively received from 5 ml of the studied blood a glycogen subject to acid hydrolysis of 1 N sulphuric acid, and determine the formed glucose by a glyukozooksidazny method.

Express methods of definition of sugars are characterized by big sensitivity, accuracy, speed and simplicity of implementation of the analysis. Their performance does not require the special equipment. At first tablet reduktometrichesky express methods were developed for definition of sugars in urine by the principle of test of Felinga. Coloring of urine after addition of reactants was compared to a color scale and defined concentration of sugars. Then various options of test pieces of paper for definition of glucose in urine and in blood with use of a glyukozooksi-dazny method were offered. These express methods differed in high specificity. For carrying out the analysis it is enough to moisten the strip of hromatografichesky paper impregnated with reactants, urine or a drop of blood, shown coloring in 1 — 2 min. to compare to the enclosed color scale and to determine concentration of glucose in test by coinciding color. Intensity of coloring of a strip can be more precisely defined in the reflective photoelectrocolorimeter. Similar test pieces of paper began to be issued in various combinations with other express methods thanks to what in 1 — 2 min. it is possible to define up to 10 components of urine. Also test pieces of paper for definition of a galactose in urine by means of enzyme of a galaktozo-oxidase were released. Use of express methods is especially perspective for diagnosis of a diabetes mellitus, control of the course of its treatment, for use in case of emergency (e.g., at suspicion on a diabetic coma) and in the areas remote from clinical laboratories.

Use of specific and adequate methods of definition of the corresponding sugars in urine and blood of the patient, studying of a condition of carbohydrate metabolism by method of loadings with various sugars with control of dynamics of metabolism of these sugars by means of glycemic (sugar) curves gives the chance to make the exact diagnosis of disturbance of carbohydrate metabolism and even to define localization of disturbance in a chain of exchange processes. Glycemic curves build by measurement of a sugar content in blood on an empty stomach and through certain time slices — 15, 30, 60, 90, 120, 150, 180 min. — after loading this sugar, carbohydrates in general or administrations of hormone; results represent in the form of the schedule, on abscissa axis postpone time in minutes for Krom, and on ordinate axis — a sugar content (.ig/100 ml).

Carbohydrates in food. At. food are divided by classification of FAO/WHO (1980) on assimilable a human body and unavailable. Unavailable At. are not hydrolyzed by enzymes went. - kish. a path, are not soaked up in intestines and if are soaked up, then are not metabolized in fabrics. In particular, carry oligosaccharides like raffinose to them, the polysaccharides which are not and - glycanes, napr, cellulose (see Cellulose), and also nek-ry simple sugar, not metaboliziruyemy in tissues of the person. Unavailable polysaccharides and lignins form group of the ballast substances (so-called food fibers) playing a significant role in maintenance of normal regulation of digestion (see) and metabolism of a number of substances.

According to the «Standards of physiological need for feedstuffs and energy for various groups of the population of the USSR» accepted in 1982, the adult at an average on weight physical. work shall receive 344 — 440 g assimilable At. in days. At especially heavy physical. work requirement in At. reaches 602 g; at the persons occupied preferential with brainwork, requirement in At. makes 297 — 378 g depending on age and a floor. At women during the period from 18 to 59 years requirement in At. is about 15% lower, than at men. With age requirement in At. decreases. By 75 years of distinction in requirement in At. at men and women about 5% decrease. At. shall cover apprx. 50 — 55% of need of an organism for energy. Such share At. in a diet allows to avoid possible adverse effects of providing an organism with energy due to excess amounts of proteins and fat. At the same time this share At. it is sufficient for providing with glucose of cells of a brain and erythrocytes, for to-rykh glucose is the only energy source. A shortcoming At. of a diet forces an organism to spend for formation of glucose of amino acid (see. Carbohydrate metabolism), what can cause their deficit in an organism and emergence of an acetonemia (see).

M. Rtsbner determined the average size of heat of combustion At. — 4,1 kcal/g. Sizes of heat of combustion separate At. make (kcal/g): glucose — 3,75, fruit

for — 3,76, lactose — 3,95, sucrose — 3,96, a glycogen — 4,19, starch — 4,20. U. Etuoter found out that in an organism At. are acquired not completely, and proposed the amendments to warmth of their combustion allowing to calculate so-called metabolpzpruye-my energy of U. Sozdana of the table, in to-rykh indicators of comprehensibility are given At. in separate groups of foodstuff (see Caloric content). In approximate calculations metabolizi-ruyemy energy At. accept equal 4 kcal! or recalculate starch and a glycogen of a diet for glucose and, neglecting allowance for its comprehensibility, multiply the received size on 3,75 kcal/g. At hydrolysis of glycosidic linkages of polysaccharides in the course of digestion it is lost apprx. 0,6% of the energy concluded in these At.; in the form of energy-rich bonds of ATP (see Vyso-koergichesky connections) accumulates only apprx. 39% of energy of glucose.

Interacting with other substances of food, At. influence their availability to an organism and the need of an organism for these substances. In the course of storage and thermal treatment of food U., having the recovering properties, interact with amino acids of proteins, forming during a number of transformations of substance, unavailable to assimilation by an organism. As a result the general comprehensibility of protein and especially comprehensibility of a lysine (see) and methionine decreases (see). Monosaccharides, forming complexes with microelements (see), can exert impact on their absorption in intestines. So-called beloksbere-gayushchy action is known At.: they lower the need for protein, interfering with use of amino acids as power material and strengthening through insulin use of amino acids for synthesis of protein. Contents in a diet At. significantly influences the need of an organism for thiamin (see). In the Arctic where the population adapted to food products with low contents At., need of the person for thiamin, according to L. E. Panin, is significantly reduced. A certain influence on assimilation of proteins, lipids, vitamins and microelements of food is rendered At., being a part of ballast substances (food fibers): they reduce digestion of protein and fat a little, can interfere with absorption of vitamins and microelements necessary for an organism.

Consumption of sucrose considerably increased in industrialized countries for the last 200 — 300 years (see). In the conditions of excess receipt of energy an organism, using the adaptive opportunities, accumulates excess metabolites in the form of fat in cells of fatty tissue — obesity develops (see). At early children's age the organism answers excess receipt of energy with the strengthened formation of lipoblasts, and further their number even at healthy nutrition long remains raised. Consumption with food of sucrose, and especially fructose (see), promotes increase in content in blood of triglycerides and cholesterol. It is shown that at the patients suffering from giperlipoproteinemi-it the IV type (see Lipoproteids), concentration of triglycerides of blood under the influence of fructose especially easily increases. Opinions on a role of surplus At. in food in development of atherosclerosis (see) and coronary heart disease (see) are contradictory. J. Yudkin upholds the concept, according to a cut excess of sucrose leads to disturbance of the hormonal status and subsequent change of lipid metabolism, the speaker as a pathogenetic link in development of these diseases. A. Keys and other opponents of this concept indicate that the frequency of these diseases correlates with consumption At. is weaker, than with consumption of saturated fats, and among alimentary factors in a pathogeny of atherosclerosis and coronary heart disease decisive preference is given to fats. Tro-uell (N. S. of Trowell) considers that these diseases are connected with deficit in diets of the population of industrialized countries of the ballast substances normalizing in his opinion, exchange of cholesterol. The hyper dysinsulinism (see) arising at the systematic use of large amounts of sucrose can lead as to dystrophic changes of insular tissue of pancreas, and to decrease in sensitivity of receptors of insulin on cellular membranes of target cells that can promote development of a diabetes mellitus (see a diabetes mellitus). It is established that the use of sucrose and other sugary products (with - m), especially in combination with violation of the rules of hygiene of an oral cavity, leads to development of caries of teeth (see). The opinion is eurysynusic that the diets rich At., promote development of allergic reactions.

In prevention of the listed diseases restriction of excess consumption of sugar is of great importance. Replacement in food of sucrose by xylitol (see) and sorbite has the known preventive value (see), to-rye are acquired worse, and also searches and synthesis of sweet substances, to-rye are not acquired by an organism (see. Sweet substances). Need of restriction digestible At., especially sugar, arises at treatment of a diabetes mellitus and obesity. Xylitol, sorbite and fructose assimilate cells of a liver without participation of insulin and therefore in comparison with sucrose have advantage in food of patients with a diabetes mellitus. At diseases of a liver, intestines, etc. apply as a part of diets honey (see), medical influence to-rogo along with other its components is attributed it At. In clinical nutrition (see clinical nutrition) vegetable products and introduction to diets rich with ballast substances as a source of these fibers of bran gain ground (see Bread, bakery products).

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