Is heat inactivation of enzymes reversible? Enzyme activation and inhibition
One of the purposes of heat treatment is to inactivate enzymes. The thermal stability of enzymes is comparable to that of microorganisms. For this reason, enzymes can be inactivated by heat treatment, as is the case with microorganisms.
During the pasteurization of acidic foods such as fermented vegetables or fruit juices, the following types of enzymes may be inactivated: pectin methylstearase and polygalacturonase. Inactivation of enzymes in these products is more important than destruction of microorganisms.
Some types of enzymes are very heat stable, such as heat-stable enzymes produced by psychrophilic bacteria. These enzymes (lipases and proteases) can limit the shelf life of UHT products such as milk.
Sometimes the intensity of thermal processes is based on the inactivation of certain enzymes, which are called indicator enzymes:
When blanching vegetables: peroxidase enzyme (sometimes catalase or others);
When pasteurizing milk: phosphatase or peroxidase, these indicator enzymes allow the milk to be classified according to the intensity of heat treatment (Figure 2.9).
Figure 2.9 - Inactivation of milk enzymes.
2.9 Optimization of heat treatment processes
D and Z values nutrients and quality indicators are usually higher than those of microorganisms. This fact makes it possible to optimize the heat treatment process towards inactivation of microorganisms and at the same time maintaining quality indicators.
The conditions depend on the type of process, but in general the best results are obtained by the intensive short-term type of process. Table 2.5 shows the loss of vitamin B 1 during sterilization.
It is easy to achieve optimization of the sterilization process of convective heated products. For liquids with or without small particles in suspension the best solution is ultra-high temperature processing.
Table 2.5 - Loss of vitamin B1 during sterilization
2.10 Estimation of F 0 values
Required value F 0 depends on the type of product and includes several factors. Great importance has the pH of the product. The higher the acidity of the product, the less stringent the sterilization regime will be.
There are 4 pH ranges.
In addition to the destruction of microorganisms, the pH value also implies:
Heat treatment less intense if the product has a low acidity pH;
pH 4.5 is critical: it is the most low level pH that allows growth C. botulinum. If the pH value is greater than 4.5, the selected process may result in complete inactivation C. botulinum or 2.45 F 0 - 3 F 0.
A pH value of 4.1 is the lowest for sterilization. In the pH range 4.1-4.5, treatment 1 is used F 0. At pH<4,1 нет необходимости проводить стерилизацию, т.к. пастеризация обеспечивает необходимый срок хранения и промышленную стерильность. Интенсивность процесса пастеризации часто определяется активностью ферментов, не микробиальной активностью.
Table 2.6 - Classification of canned food according to pH.
thermophilic microorganisms and characteristic enzymesPh.D.
Kuznetsova Ekaterina Igorevna Mechanisms of enzyme inactivation
1. Change of primary structure:
1.1. Polypeptide chain rupture:
Severe conditions (prolonged boiling in HCl) –
hydrolysis to individual amino acids.
When heated to 100 °C (pH 7-8), hydrolysis
peptide bonds are insignificant.
Most sensitive to
high temperature hydrolysis are
peptide bonds formed by residues
aspartic acid.
Proteases (bacterial contamination, autolysis). Solution:
inactivated enzymes. 1.2.Oxidation of enzyme functional groups
SH groups of cysteine and indole fragments
tryptophan, at elevated temperatures, can
oxidize (sulfoxy-cysteine compounds
(SOH, SO2H) and products are formed
opening of the indole ring of tryptophan. Solution:
Reactivate with restoratives
agents, in particular low molecular weight thiols
(for example, cysteine or dithiothreitol).
Caused by: Thiols and other reduced
sulfur compounds, for example Na2SO3, Na2S2O3.
Disulfide bond reduction product
(S-S) is:
1) thiol form (protein–SH)
2) mixed disulfide of the thiol form of the protein with
a reducing reagent, for example
protein–S–SO3). 1.3. Cleavage of disulfide bonds
Alkaline hydrolysis of cysteine →dehydroalanine→
Due to its nucleophilic properties
interacts with NH2 groups of lysine and SHcysteine →lysinoalanine and lanthionine.
For complete destruction of all S–S bonds, fairly stringent conditions are required (0.1–1 M alkali,
100 °C).
However, the destruction of the most reactive
S–S bonds can occur in fairly soft
conditions - for example, at temperatures of 60–80 ° C and
slightly alkaline pH values.
Should be taken into account when using enzymes in
as additives to detergents. Solution:
Addition of thiols to the medium will lead to
cleavage of mixed disulfide and
subsequent formation of the correct S–S bond 1.4. Chemical modification of catalytic SH groups.
Heavy metal cations (Hg, Pb and Cu)
bind to the SH groups of the active site
enzyme
↓
Formation of the corresponding mercaptides
↓
The enzyme is inactivated
10.
1.5. Phosphorylation of proteins in vivo.Under the influence of phosphorylase and phosphatase,
contained in semi-purified enzymatic
drugs in the form of impurities
↓
Phosphoric acid binds to OH groups
serine and threonine.
↓
Conformational changes in protein
molecule
↓
enzyme inactivation.
11.
Solution:There are practically no examples in the literature
good luck reactivating this way
inactivated enzymes.
12.
1.6. Deamination of asparagine residues.At temperatures (about 100 °C) and pH (about
4.0–5.0) deamination of residues occurs
asparagine.
↓
enzyme inactivation.
13.
Solution:There are practically no examples in the literature
good luck reactivating this way
inactivated enzymes.
14.
1.7. Radiation inactivation of enzymesγ-irradiation and UV light
Affect functional groups
enzymes, peptide bonds and SH groups
cysteine residues.
15.
2. AggregationObserved at elevated temperatures, at
extreme pH values, in the presence
some chemical compounds.
The higher the concentration, the faster it goes
aggregation.
Hydrophobic interactions and hydrogen
bonds, the formation of disulfide bonds is possible
bridges between individual proteins
molecules
16.
Solution:It is necessary to destroy intermolecular
covalent and non-covalent contacts c
using concentrated solutions
urea and guanidine chloride, extreme
pH values.
If the aggregation of enzymes results in the formation of
intermolecular S-S bridges are added to the medium
relatively low concentrations
(μmol/L) thiol-containing reagents (e.g.
cysteine or dithiothreitol).
At such concentrations, intramolecular
S–S bonds in the protein are usually not affected.
17.
3. Inactivation of enzymes by surfacetension
Surface tension at the interface
between air and clean water is 80
din/cm.
Foaming causes denaturation
enzymes adsorbed at the interface
phases
18.
Solution:Adding a surfactant reduces the surface
tension up to 1 dyne/cm.
19.
4. Sorption of protein on the walls of the reactionvessel
Sorption due to non-covalent interactions
leads to a decrease in enzyme concentration in
solution.
Must be taken into account when working with
diluted protein solutions
(concentration 10-8–10-10 mol/l).
Under the influence of denaturing factors
ability of proteins to adsorb on walls
reaction vessel may increase.
20.
Solution:Desorption of enzyme from the walls of the reaction
the vessel is achieved through destruction
nonspecific interactions between
protein and sorption centers on the surface
vessel.
Extreme pH values can be used
concentrated solutions of urea or
guanidine chloride.
21.
5. Dissociation of oligomeric proteins intosubunits
Caused by: Urea, detergents, acids or
heating.
Lead to:
conformational changes of individual
subunits;
subunit aggregation;
dissociation of cofactors from active centers;
modifications of functional groups that
oligomeric protein were shielded from
contact with solvent.
22.
6. Desorption of cofactor from the active siteenzyme
Causes: heating, chelating effects, dialysis
If cofactor dissociation is accompanied
significant conformational shifts or
chemical modification of important
functional groups → enzyme
is irreversibly inactivated.
If no significant
changes in protein conformation, then adding
in an environment of excess cofactor leads to
enzyme reactivation.
23.
Cofactor regenerationRegeneration methods:
Enzymatic (methods using conjugated substrates or enzymes)
Non-enzymatic (chemical and
electrochemical approaches)
24.
Enzymatic methodExcessive amounts are introduced into the system.
conjugate substrate of the same enzyme:
Example: when alcohol dehydrogenase works
NADH is consumed.
25.
Enzymatic method1. Use of conjugated substrates.
Disadvantage:
high concentrations are used
conjugated substrate, since the equilibrium
reactions are greatly shifted to the side
alcohol formation;
complicates the procedure for identifying the main
product from the reaction mixture.
26.
Enzymatic method2. Use of paired
enzymatic reactions
Enzyme 2 is additionally introduced into the system,
whose functioning is ensured
coenzyme regeneration.
The enzymes used in the system must have
different substrate specificity
27.
Non-enzymatic methods1. Chemical methods.
Sodium dithionite and some
pyridinium salts:
+ Low cost.
- can inhibit certain enzymes.
Flavin coenzymes
28.
Non-enzymatic methods2. Electrochemical methods.
Direct electrochemical reduction or
oxidation.
“-” appearance during the regeneration process
enzymatically inactive forms of coenzyme,
for example, as a result of its dimerization.
29. STABILIZATION OF ENZYMES IN BIOTECHNOLOGICAL SYSTEMS
30.
Problems encountered during useenzymes in biotechnological processes:
1. Elevated temperatures
2. Extreme pH values
3. High concentrations of organic
solvents or surfactants.
4. Inability to reuse
enzyme.
5. Difficulty in separating the enzyme from
product.
31.
Basic approaches for stabilizationenzymes:
1. Adding stabilizing substances to the medium,
in which the enzyme is stored or carried out
enzymatic reaction.
2. Chemical modification of the enzyme.
3. Immobilization of the enzyme.
32.
1. Substrates or their analogues:
The enzyme-substrate complex is often more
more stable than the free enzyme.
Example: Lactate dehydrogenase in the presence
lactate is more heat stable.
33.
Enzyme stabilization using:2. Organic solvents:
Polyhydric alcohols stabilize some
enzymes by increasing stability
intramolecular protein hydrogen bonds.
Example: Chymotrypsin in the presence of 50–90%
glycerol is more resistant to proteolysis
34.
Enzyme stabilization using:3. Soleil:
At low salt concentrations (<0,1M) катионы
Ca2+, Zn2+, Mn2+, Fe2+, etc. can specifically
interact with metalloproteins.
Some of them are cofactors.
Ca2+ is capable of stabilizing tertiary
the structure of a number of proteins due to the formation
ionic bonds with two different
amino acid residues.
Example: α-Amylase (from bacillus caldolyticus)
Ca2+ significantly increases thermal
sustainability.
35.
36.
Chemical modification of the enzyme1. The enzyme takes on a more stable
conformation.
2. Introduction of new functional groups into the protein
leads to the formation of additional
stabilizing hydrogen bonds or salt
bridges.
3. When using non-polar compounds
hydrophobic interactions are enhanced.
4. Modification of hydrophobic surface areas
protein by hydrophilic compounds reduces
area of unfavorable contact of external
non-polar residues with water.
Example: glutaraldehyde
37.
Enzyme immobilization allows:Increase enzyme stability (heat,
autolysis, exposure to aggressive environments, etc.)
1. Reuse the enzyme
2. Separate enzyme from reagents and products
reactions.
3. Interrupt the reaction at the right moment.
38.
Immobilized enzymes are drugsenzymes whose molecules are associated with
carrier, while retaining completely or
partly its catalytic properties.
Immobilization methods:
1. Chemical
2. Physical
39.
Immobilization methods:The following media can be used:
1)Organic materials:
1.1) natural (polysaccharides, proteins, lipids)
1.2) synthetic polymer carriers
2) Inorganic materials (matrices on
based on silica gel, clay, ceramics, natural
minerals, etc.)
40.
1) adsorption of the enzyme on an insoluble carrier
as a result of electrostatic, hydrophobic,
van der Waals and other interactions;
;
structures;
4) Connection to a two-phase system.
41.
Methods of physical immobilization:Achieved by contact of an aqueous solution
enzyme with a carrier.
42.
Methods of physical immobilization:1) adsorption of the enzyme on an insoluble carrier
Factors influencing adsorption:
1. Specific surface area and porosity of the carrier
2. pH value (on non-ion exchangers max adsorption
at the isoelectric point of the protein)
3. Ionic strength of the solution (increasing ionic strength -
enzyme desorption, but sometimes the opposite situation
“salting out”)
4. Enzyme concentration.
5. Temperature (on the one hand denaturation, on the other
another accelerated diffusion)
43.
Methods of physical immobilization:1) adsorption of the enzyme on an insoluble carrier
Advantages:
2) Media availability
Flaws:
1) Insufficient bonding strength
2) Many media are biodegradable
44.
Methods of physical immobilization:2) inclusion of the enzyme in the semipermeable
capsule, in a semi-permeable membrane
45.
Methods of physical immobilization:2) inclusion of the enzyme in the semipermeable
capsule, in a semi-permeable membrane
Advantages:
1) Relative simplicity of the technique
2) Protection against microorganisms
3) There are no diffusion restrictions (since
The surface to area ratio is high and
membrane thickness is small)
Flaws:
1) Biodegradable
2) Not applicable for high molecular weight
46.
Methods of physical immobilization:3) mechanical inclusion of the enzyme in the gel
structures
The enzyme is included in a three-dimensional network
polymer chains that form a gel.
47.
Methods of physical immobilization:3) mechanical inclusion of the enzyme in the gel
structures
Should be considered:
1. Correspondence of pore size to the size of the enzyme.
2. The nature of the matrix (since it creates
microenvironment for the enzyme, maybe
create a pH different from the pH of the solution and
increase the affinity of the substrate for the matrix, which
increases the rate of enzymatic reaction)
48.
Methods of physical immobilization:3) mechanical inclusion of the enzyme in the gel
structures
Advantages:
1) Relative simplicity of the technique
2) Increased mechanical, chemical and
thermal resistance of matrices.
3) The enzyme is stabilized
4) The enzyme is protected from bacterial
damage
Flaws:
1) Not applicable for high molecular weight
49.
Methods of physical immobilization:4) Connection to a two-phase system
The enzyme is soluble in only one of the phases, and
product - to another
Allows you to work in high molecular weight
substrates.
50.
Chemical immobilization methods:Formation of covalent bonds between
enzyme and carrier.
Advantages:
1) High strength of the conjugate
2) Enzyme stability can be increased
51.
When immobilizing enzymes, it is necessarycomply with the following conditions:
1. Active groups of the matrix should not
block the catalytic center of an enzyme.
2. Immobilization should not lead to loss
enzyme activity.
52.
Very promising is the use inas immobilized biocatalysts
cells.
Because can be avoided:
1) expensive isolation and purification steps
enzymes
2) the need for their subsequent stabilization
53.
ThermozymsStable under high temperature conditions,
high salt concentrations and extreme
pH values.
Hyperthermophilic microorganisms
found among Archaea and Bacteria, live
at temperatures of 80–100 °C.
54.
Mechanisms responsible for thermal stabilityenzymes in thermozymes:
Between mesophilic and thermophilic
enzyme versions - high degree of homology
sequences and structures.
Thus, sequences of thermostable
dehydrogenases from Pyrococcus and Thermotoga at 35 and
55% respectively identical
mesophilic dehydrogenase sequences
from Clostridium.
55.
It was discovered that dehydrogenase from Pyrococcusfuriosus (Tm == 105 °C) contains 35 isoleucines,
while dehydrogenases from Thermotoga
maritima (Tm = 95 °C) and Clostridium symbiosum (Tm
= 55 °C) only 21 and 20 isoleucines
respectively.
Heat-stable enzymes contain less
glycine: Cs dehydrogenase contains 48 residues
glycine, and dehydrogenases from Tm and Pf only
39 and 34 glycines, respectively.
More isoleucine and less glycine.
56.
Increased thermal stability correlates:1) with increasing rigidity of the protein structure
by reducing the content of residues
glycine,
2) with improvement of hydrophobic contacts in the core
dehydrogenase from Pf as a result of valine replacement
isoleucine. (As a result of site-directed
mutagenesis leading to isoleucine replacement
valine thermostability mutants
decreased).
57.
Stabilization mechanisms:minimizing the available hydrophobic area
protein surface;
optimization of protein atom packing
molecules (minimizing the ratio
surface/volume);
optimization of charge distribution (achieved
thanks to the elimination of repulsive
interactions, as well as as a result of the organization
interactions between charges into a peculiar
net)
Reducing the number of depressions
58.
Application of enzymes from extremophilesModern technologies of molecular biology
and genetic engineering allows:
1) obtain sufficient amounts of enzymes from
extremophiles for their subsequent
analysis and practical application.
2) cloning and expression of these enzymes in
mesophilic organisms.
59.
Starch is used to produce sugars.
First, the process is carried out at (95–105 °C) and at values
pH 6–6.5.
At the next stage, the temperature drops to 60°C and
pH=4.5.
The use of thermostable enzymes (αamylase, glucoamylase, xylose isomerase),
isolated from hyperthermophiles will allow:
1) carry out the process in one stage and at the same
the same conditions
2) abandon expensive ion exchangers
60.
Application of enzymes from extremophiles:The most thermostable α-amylases were
found in the archaea Pyrococcus woesei,
Pyrococcus furiosus, Desulfurococcus mucosus,
Pyrodictium abyssi and Staphylothermus
marinus. Amylase genes from Pyrococcus sp. were
cloned and expressed in E.coli and Bacillus
subtilis.
61.
Application of enzymes from extremophiles:Proteolytic enzymes
Serine alkaline proteinases are widely
used as additives to detergents
means.
Proteinases from extremophiles retain
nativeness at high temperatures, in
presence of high concentrations of detergents and
other denaturing agents. Pyrococcus,
Thermococcus, Staphylothermus, Desulfurococcus and
Sulfolobus. The maximum activity of these
enzymes develop at temperatures
from 90 to 110 °C and pH values from 2 to 10
62.
Application of enzymes from extremophiles:DNA polymerases
Thermostable DNA polymerases are used
in PCR and play an important role in genetic engineering.
Thermostable polymerases have been found in
hyperthermophiles Pyrococcus furiosus and Pyrococcus
litoralis, as well as in thermophiles Thermus aquaticus.
All influences leading to inactivation of enzymes are sometimes conventionally divided into physical and chemical. Physical include heating or hypothermia, irradiation (y- and X-ray radiation), ultrasound, sorption on
phase boundaries (such as water - air or liquid - liquid). Chemical inactivation can be caused by, for example, alkalis to acids, surfactants, organic solvents, urea and guanidine chloride, certain oxidizing agents (e.g. oxygen or hydrogen peroxide) and reducing agents (e.g. thiols, metal ions), as well as some enzymes (for example, proteases or protein kinases). However, an attempt to classify inactivation processes based on the conditional division of inactivating effects into physical and chemical ones does not provide practically anything for understanding the essence of these processes. For example, under the influence of a physical factor (heating) chemical changes often occur in a protein molecule; oxidation of functional groups, hydrolysis of peptide bonds. On the other hand, the action of such chemical denaturants as urea or guandinine chloride, as a rule, causes changes only in the physical state of the protein (conformational rearrangements), but does not change its chemical structure.
More informative, from the point of view of solving the stabilization problem, is the classification of inactivation processes by molecular mechanisms.
§ 2. Molecular mechanisms of enzyme inactivation
Back in the 40s and early 50s, basic ideas about the mechanisms of inactivation were formed. In the most general case, the inactivation process can be represented as a two-stage scheme:
where N, D and 1 are, respectively, the native, reversibly denatured and irreversibly inactivated forms of the protein*. The first stage in the diagram (!) most often represents a reversible conformational change; in the case of oligomeric enzymes, this stage consists of reversible dissociation into subunits. Following reversible processes, irreversible stages occur (D-L)< Механизмы инактивации ферментов, как правило, классифицируют, исходя из природы процессов, происходящих именно на второй, необратимой стадии. Кратко рассмотрим основные ииактивационные механизмы.
Aggregation. Very often during prolonged incubation in plants at elevated temperatures, at extreme pH values t
*Term<кнеобратимость» по ей ношению к инактивации имеет t\gt the meaning is that after removing the inaction-anion effect (for example, when the temperature decreases after 1 phase<мжнтельн^го нагревания) фермент не втвращается h иатнвной каталитически активной информации N. Он остается в неактивной форме 1 и в течение разумных времен наблюдения (часы. с\тки) ш- списобен само произвольно реактивироваться, т, е. перейти в форму N,"
in the presence of chemical denaturants, proteins aggregate. The possibility of such inactivation is influenced by a number of factors: temperature, pH, etc.; however, the decisive factor among them is the protein concentration. Since the kinetic order of the equation describing the aggregation stage is equal to or even greater than two, then, naturally, an increase in protein concentration leads to an increase in the rate of aggregation and the size of the resulting aggregates, as well as an acceleration of inactivation in general. Based on this characteristic feature (the strong dependence of the inactivation rate on the enzyme concentration in solution), aggregation can be kinetically distinguished from monomolecular inactivation mechanisms.
As a rule, protein aggregates are formed due to weak non-covalent interactions, such as hydrophobic interactions, hydrogen bonds. However, if protein molecules contain SH groups or, in addition to them, S-8 bonds, then individual molecules inside the aggregates can be cross-linked by covalent disulfide bridges. The size and shape of non-covalent or covalently cross-linked aggregates can vary within wide limits up to the formation of a separate phase - protein sediments.
Change in primary structure. All chemical processes leading to protein inactivation can be divided into two groups. The first includes reactions of breaking the sex and peptide chain; the second includes chemical modification of individual functional groups of the protein.
Hydrolysis of peptide bonds, proteolysis and autolysis. Non-catalytic melting of peptide bonds takes place under very harsh conditions. Thus, complete cleavage of the polypeptide chain into individual amino acid components is achieved only by prolonged (many hours) boiling of a protein solution in concentrated hydrochloric acid. Under somewhat “milder” conditions, when protein solutions are heated at neutral or slightly alkaline pH and a temperature of 80-100°C, the hydrolysis of peptide bonds either occurs only slightly or is not observed at all. Of all peptide bonds, those formed by aspartic acid residues are usually the most labile to high-temperature hydrolysis.
However, hydrolysis of peptide bonds in proteins can also occur under normal conditions - room temperature, neutral pH values. This is the result of the work of proteases - enzymes created by nature to degrade other proteins under mild conditions. Since any (even highly purified) protein preparations may contain proteases as accompanying impurities, when studying the mechanisms of inactivation, it is necessary to take into account the possibility of proteolysis. f Another example of proteolytic inactivation is bacterial contamination of reactors containing enzymes. Microorganism cells that accidentally entered the reactor
They secrete proteases that break down the molecules of the biocatalyst enzyme in solution. Using the “shards” of proteolytic degradation as a growth medium, microorganisms multiply; Thus, on the one hand, they “clog” the reactor, on the other, they reduce the activity of the biocatalyst in the solution, i.e., they inactivate it.
Proteolytic enzymes themselves are capable of breaking down not only molecules of other proteins, but also similar ones. This process of “self-cleavage” of proteases is called a vtoliz A. Autolysis can be distinguished kinetically from most other inactivation mechanisms (with the exception of aggregation). The fact is that an essential stage in autolysis is the formation of a complex between two protease molecules; this bimolecular step often determines the overall rate of inactivation. Therefore, if, with a change in the initial concentration of the protein, a change in the rate of inactivation is observed*, then the inactivation process being studied With most likely represents autolysis.
Oxidation of enzyme functional groups. At elevated temperatures, some functional groups in proteins, and primarily the SH groups of cysteine and indole fragments of tryptophan, are oxidized. As a result of oxidation, modified amino acid derivatives are formed; sulfoxy compounds of cysteine (SOH, SCW, etc.), products of opening of the indole ring of tryptophan, etc. In some enzymes, sulfhydryl groups that are part of the active center have increased reactivity and are oxidized even at room temperature.
S-cleavage S-bonds in proteins. Cleavage can occur either in a reducing environment (in the presence of thiols, other reduced sulfur compounds, for example Nagar3, NaACbh, or in an alkaline environment at elevated temperatures. In the first case, the product of reduction of the S-S bond is its thiol form (protein -SH) or a mixed thiol disulfide forms of a protein with a reducing reagent (protein -S-S-R; protein -S-SOr, etc.). When alkaline cleavage of S-S bonds occurs, a more complex chain of chemical reactions occurs. First, cystine is hydrolyzed to form dehydro-alanine:
i-СНг-СН<^ + ОН ~ -* CHSN-CH^S-S~ + CH g = C
which, as a nucleophile, interacts with the amino groups of lysine residues, sulfhydryl groups of cysteine residues, guanidinium groups of arginine residues, forming new amino acids, respectively, lysinoalanine, lanthionine n orni-thnioalanine:
soon h hoon
Local hypothermia (ice on the stomach)
Use of proton pump blockers
9. Characteristic disorders of pancreas secretion in chronic pancreatitis:
Increased amylase activity
Increased lipase activity
Excretory enzyme deficiency
Hyperinsulinism
Increased trypsin activity
10. The clinical picture of pancreatic necrosis is not characterized by:
Girdle pain in the abdomen
Repeated vomiting
Pneumoperitoneum
Collapse
Intestinal paresis
OPTION 2
1. The most informative method of instrumental diagnostics for suspected acute pancreatitis:
Celiacography
Laparocentesis
ERCP
FGDS
2. The main complications of acute destructive pancreatitis are (one extra answer):
Pain shock
Gallbladder perforation
Peritonitis
Retroperitoneal phlegmon
Arrosive bleeding
3. In the pathogenesis of acute pancreatitis, the leading role belongs to:
Aggressive effects of hydrochloric acid on the parenchyma of the gland
Development of infection in the parenchyma of the gland
Activation of enzymes in the gland and its autolysis
Development of the sclerosing process in the parenchyma of the gland
Aggressive effects of pepsin on the gland parenchyma
4. Weakening of the pulsation of the abdominal aorta in acute pancreatitis is called a symptom:
Mayo-Robson
Ortner
Murphy
Mondora
Voskresensky
5. Signs of endocrine pancreatic insufficiency in chronic pancreatitis:
Hyperbilirubinemia
Creatorea
Hyperglycemia, glycosuria
Decreased activity
Steatorrhea
6.Pancreatic cancer corresponding to T3:
Extends beyond the pancreas but does not involve the celiac or mesenteric artery
Extends to the celiac or mesenteric artery
Preinvasive carcinoma
Tumor limited to pancreas up to 2cm
Tumor limited to pancreas more than 2cm
7.The most characteristic of acute pancreatitis are pains with irradiation:
To the right thigh
In the back
To the right shoulder blade
In the left shoulder girdle
In the right shoulder girdle
8. The most informative method for diagnosing pancreatic necrosis is:
Esophagogastroduodenoscopy
Laparocentesis
Laparoscopy
Plain fluoroscopy of the abdominal cavity
9.Acquired cysts of the pancreas include (one extra answer):
Retention cysts
Degenerative
Proliferating cystadenomas
Proliferating cystadenocarcinomas
Teratoid
10. The optimal option for surgery for pancreas cysts:
External drainage
Internal drainage
Marsupilization of the cyst
Fenestration of the cyst
OPTION 3
1.Method that prevents enzymatic autolysis of the pancreas:
Drainage of the thoracic lymphatic duct
Use of cytostatics
Plasmapheresis
Hemosorption
Peritoneal dialysis
2. Mechanism of therapeutic action of cytostatics in acute pancreatitis:
Suppression of gastric secretion
Reducing inflammation in the gland
Improving microcirculation in pancreas
Suppression of exocrine gland function
Normalization of the endocrine function of the gland
3. Pain on palpation in the left costovertebral angle is characteristic of the symptom:
Voskresensky
Mayo-Robson
Courvoisier
Mondora
Murphy
4. Drugs for the treatment of acute pancreatitis (one extra answer):
- antispasmodics (baralgin, atropine)
- cytostatics (5-fluorouracil, cyclophosphamide)
- protease inhibitors (contrical, gordox)
- somatostatin analogues (sandostatin, stylamine)
- drugs (morphine)
5. Forms of acute pancreatitis (one extra answer):
- acute edema
- hemorrhagic pancreatic necrosis
- fatty pancreatic necrosis
- mixed pancreatic necrosis
- pancreatic cyst
6. The development of acute pancreatitis can lead to (one extra answer):
Closed pancreatic injury
Surgical trauma to the pancreas
Pinched Stone BDS
BDS stricture
Cirrhosis of the liver
7.Detoxification methods for acute pancreatitis include (one extra answer):
Plasmapheresis
Blood transfusion
Hemosorption
Intestinal dialysis
Intestinal intubation
8. The optimal option for surgery for a suppurating pancreas cyst:
Percutaneous external drainage under ultrasound guidance
Gastrocystostomy
Pancreaticoduodenectomy
Marsupilization of the cyst
Fenestration of the cyst