scholarly journals ENHANCEMENT OF THE OPSONIZING AND AGGLUTINATING POWERS OF ANTIPNEUMOCOCCUS SERUM BY SPECIFIC PRECIPITATING SERUM

1920 ◽  
Vol 32 (3) ◽  
pp. 283-293 ◽  
Author(s):  
Ida W. Pritchett
Keyword(s):  
Horse Serum ◽  
Test Tube ◽  
Immune Serum ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Type I ◽  
Type Ii ◽  
Normal Horse Serum ◽  
Serum Type

1. No demonstrable antiopsonins are formed in rabbits following the intravenous injection of monovalent pneumococcus horse sera, Types I, II, and III. 2. The serum of rabbits injected with immune pneumococcus horse serum, Type I, II, or III, or with normal horse serum, when mixed in the proportion of 1:4 with Type I or Type II pneumococcus horse serum, can greatly augment, in vitro, the opsonization and agglutination of Type I and Type II pneumococci by the homologous immune horse sera. No similar effect is obtained with Type III serum and pneumococci. 3. The increase in opsonization and agglutination is dependent upon (a) specific sensitization of the pneumococci by the homologous immune serum and (b) the presence of the precipitating serum. In the absence of sensitization, as when a heterologous or normal horse serum is employed, opsonization and agglutination do not occur, even though a precipitating mixture is provided. The substitution of normal rabbit serum for the precipitating rabbit serum gives opsonization and agglutination in dilutions slightly higher than are effected with salt solution only, due possibly to the more favorable medium created for the leucocytes by the addition of 25 per cent of whole rabbit serum. 4. Different methods of combining the immune horse serum, precipitating rabbit serum, and pneumococci yield very similar results, preliminary sensitization of the bacteria before precipitation, or precipitation in the rabbit-horse serum mixture before the addition of the pneumococci for sensitization causing little if any difference in result from that obtained when immune horse serum, precipitating rabbit serum, and pneumococci are all mixed and incubated together. 5. This increased opsonization in the test-tube does not seem to be paralleled by increased protective power, or at any rate such protection is not readily demonstrated.

scholarly journals FURTHER EXPERIMENTS WITH THE INTRADERMAL PNEUMOCOCCUS INFECTION IN RABBITS

1928 ◽  
Vol 48 (3) ◽  
pp. 413-429 ◽  
Author(s):  
Kenneth Goodner
Keyword(s):  
Horse Serum ◽  
Blood Stream ◽  
Immune Serum ◽  
Rabbit Serum ◽  
Exact Nature ◽  
Normal Rabbit Serum ◽  
Type I ◽  
Early Recovery ◽  
Simple Method ◽  
Therapeutic Value

1. The continuation of our experiments with intradermal Type I pneumococcus infection in rabbits has furnished further evidence of the marked analogies between this condition and that of human lobar pneumonia. 2. It has been found that the amount of antiserum necessary for successful therapy increases as the disease progresses, and that this progression has a definite mathematical character. Such a condition, it seems, can only be caused by a progressive accumulation of some toxic or antagonistic substance, the exact nature of which is not known. 3. Various lots of antipneumococcus sera have been tested for their therapeutic properties. The results from seven such sera show that this therapeutic value does not parallel the mouse-protective value. It is suggested that the rabbit technic may prove useful for the routine comparison and standardization of antipneumococcus sera since it represents a simple method for determining that property for which the serum is to be utilized. 4. The effect of non-specific therapy in this condition has been determined to be a transient disappearance from the blood stream of circulating organisms. This result was obtained with such heterologous materials as normal horse serum and typhoid vaccine but not with the homologous normal rabbit serum. 5. Rabbits recovering from the intradermal disease without treatment or with such inadequate treatment that the disease runs its normal course, were shown to have a definite though not permanent immunity. Cases in which the disease had been arrested at 24 hours by effective therapy with heterologous immune serum showed no immunity after the early disappearance of the passively administered elements. Cases which were brought to early recovery with immune homologous serum did show a definite immunity comparable to that which was developed in other animals as the result of an untreated course of the disease. 6. The immunity conferred by single and multiple vaccination is reported. The possibility of the application of such methods in the pneumonias of man is discussed and a method for such an application is suggested.

scholarly journals CHEMO-IMMUNOLOGICAL STUDIES ON CONJUGATED CARBOHYDRATE-PROTEINS

1937 ◽  
Vol 66 (2) ◽  
pp. 191-205 ◽  
Author(s):  
Walther F. Goebel ◽  
Rollin D. Hotchkiss
Keyword(s):  
Carboxylic Acids ◽  
Galacturonic Acid ◽  
Horse Serum ◽  
Type I ◽  
Specific Antibodies ◽  
Cross Reactions ◽  
Normal Horse Serum ◽  
High Dilutions ◽  
Serum Type

1. Azoprotein antigens containing glucuronic and galacturonic acids give rise in rabbits to specific antibodies. The immune sera show no serological crossing with antigens containing glucose or galactose. 2. The galacturonic acid antigen reacts in antipneumococcus horse serum Type I in high dilutions. 3. Azoprotein antigens containing galacturonic acid, benzene sulfonic and carboxylic acids precipitate in antipneumococcus horse sera of various types but not in normal horse serum. The mechanism underlying these cross reactions is discussed.

scholarly journals CRYSTALLINE PNEUMOCOCCUS ANTIBODY

1949 ◽  
Vol 32 (6) ◽  
pp. 705-724 ◽  
Author(s):  
John H. Northrop ◽  
Walther F. Goebel
Keyword(s):  
Ammonium Sulfate ◽  
Horse Serum ◽  
Insoluble Fraction ◽  
Rabbit Serum ◽  
Type I ◽  
Type Ii ◽  
Serum Globulin ◽  
Saturated Ammonium Sulfate ◽  
Diphtheria Antitoxin ◽  
Specific Polysaccharide

1. The immune precipitate formed by antipneumococcus horse serum and the specific polysaccharide is not hydrolyzed by trypsin as is the diphtheria toxin-antitoxin complex, and purified pneumococcus antibody cannot be isolated by the method used for the isolation and crystallization of diphtheria antitoxin. 2. Type I pneumococcus antibody, completely precipitable by Type I polysaccharide, may be obtained from immune horse serum globulin by precipitation of the inert proteins with acid potassium phthalate. 3. The antibody obtained in this way may be fractionated by precipitation with ammonium sulfate into three main parts. One is insoluble in neutral salts but soluble from pH 4.5 to 3.0 and from pH 9.5 to 10.5. This is the largest fraction. A second fraction is soluble in 0.05 to 0.2 saturated ammonium sulfate and the third fraction is soluble in 0.2 saturated ammonium sulfate and precipitated by 0.35 saturated ammonium sulfate. The second fraction can be further separated by precipitation with 0.17 saturated ammonium sulfate to yield a small amount of protein which is soluble in 0.17 saturated ammonium sulfate but insoluble in 0.25 saturated ammonium sulfate. This fraction crystallizes in poorly formed, rounded rosettes. 4. The crystallization does not improve the purity of the antibody and is accompanied by the formation of an insoluble protein as in the case of diphtheria antitoxin. 5. None of the fractions obtained is even approximately homogeneous as determined by solubility measurements. 6. Purified antibody has also been obtained by dissociating the antigen-antibody complex. 7. The protective value of the fractions is quite different; that of the dissociated antibody being the highest and that of the insoluble fraction, the lowest. 8. All the fractions are immunologically specific since they do not precipitate with Type II polysaccharide nor protect against Type II pneumococci. 9. All the fractions give a positive precipitin reaction with antihorse rabbit serum. The dissociated antibody gives the least reaction. 10. Comparison of the various fractions, either by their solubility in salt solution or through immunological reactions, indicates that there are a large number of proteins present in immune horse serum, all of which precipitate with the specific polysaccharide but which have very different protective values, different reactions with antihorse rabbit serum, and different solubility in salt solutions.

scholarly journals A STUDY OF PNEUMOCOCCI REACTING WITH ANTIPNEUMOCOCCUS SERA OF TYPES I, II, AND III, WITH AN OBSERVATION OF A MUTATION OF ONE OF THE STRAINS

1919 ◽  
Vol 30 (2) ◽  
pp. 123-146 ◽  
Author(s):  
Mildred C. Clough
Keyword(s):  
Ascitic Fluid ◽  
Horse Serum ◽  
The Body ◽  
Blood Agar ◽  
Broth Culture ◽  
Type I ◽  
Type Ii ◽  
Human Beings ◽  
Cultural Characteristics ◽  
Normal Horse Serum

In this paper are reported the results of a study of nine strains of pneumococci agglutinating with antipneumococcus sera of all three types (Nos. I, II, and III). Seven of the strains were the cause of serious or fatal infections in human beings. Morphologically they were typical pneumococci with characteristic growth on ordinary media. Most of the strains were soluble in bile, fermented inulin, and caused no precipitation on glucose ascitic fluid agar. Two of the strains, however, resembled streptococci in these three cultural characteristics, but have been regarded as pneumococci on account of their serological reactions. Variations in the cultural reactions occurred with several strains while they were under observation. The virulence of the strains varied greatly, some strains being almost non-pathogenic, and others killing mice in doses of 0.000001 cc. of a 24 hour broth culture. Antipneumococcus Sera I, II, and III agglutinated all the strains in fairly high dilution (1:8 to 1:64 or higher), while normal horse serum caused no agglutination. Antipneumococcus Sera I, II, and III stimulated active phagocytosis of all the strains, while no phagocytosis occurred in control preparations with normal horse serum. These strains elaborated a soluble substance in the body of inoculated mice which caused the formation of a precipitate when the peritoneal washings, cleared by centrifugalization, were added to the antipneumococcus sera of all three types. Antipneumococcus Sera I, II, and III protected mice equally well against 1,000 to 10,000 times the minimal lethal dose of the two strains with which protection tests could be carried out. Absorption of serum of Types I and II with the homologous pneumococcus removed the agglutinins and the bacteriotropins for all these strains. Absorption of these sera with Strains T and N removed the agglutinins and the bacteriotropins for the homologous strain only, and not for typical members of Type I or II, or for the other atypically agglutinable strains reported in this paper. The agglutinins concerned in the agglutination of these peculiar strains are therefore minor agglutinins. As shown not only by agglutination tests, but also by protection tests and agglutinin absorption tests, these organisms bear the same relation to Types I, II, and III, as do atypical Type II strains to Type II. Immune sera were prepared with these strains, and each strain was tested with all the immune sera by means of phagocytic and agglutinative reactions. In general, the strains were found to be serologically distinct, though some interrelationships existed between Strains V and R, and between Strains H, F, and N. These sera had no activity towards strains belonging to Type I or II, or atypical Type II. A mutation occurred in one of the strains, B, while it was under observation. On isolation this strain had the cultural reactions of a typical pneumococcus, and had the phagocytic and agglutinative reactions of an atypical Type II. After 6 months cultivation on blood agar its serological reactions changed, and it became actively phagocyted and agglutinated in antipneumococcus sera of Types I, II, and III. Its cultural characteristics also changed, and it became bile-insoluble, did not ferment inulin, and caused precipitation in glucose ascitic fluid agar. At this time it caused an intense green discoloration at the base of the blood agar slants around the water of condensation. By repeated animal passages this strain was three times made to revert abruptly to its original form (atypical Type IIa), both in cultural and serological reactions. An immune serum was prepared to each form of the strain, and each serum acted strongly on the homologous form, but was without action on the heterologous form of the strain. This mutation suggests that these pneumococci reacting with all three types of antipneumococcus sera may represent primitive, relatively undifferentiated forms from which the fixed types may have arisen.

scholarly journals STUDIES ON IMMUNOLOGICAL RELATIONSHIPS AMONG THE PNEUMOCOCCI

1929 ◽  
Vol 49 (2) ◽  
pp. 183-193 ◽  
Author(s):  
John Y. Sugg ◽  
James M. Neill
Keyword(s):  
Horse Serum ◽  
Rabbit Serum ◽  
Type I ◽  
Type Ii ◽  
Immunological Relationship ◽  
The Individual ◽  
Relationship Of ◽  
Convincing Data

The paper reports evidence of an immunological relationship between one variety of Saccharomyces ceremsise and the Type II variety of Diplococcus pneumonix (Pneumococcus). The most convincing data consisted of the reactions of the Type II bacteria with potent antiyeast serum which agglutinated, and protected mice against these pneumococci as well as the average antiserum obtained by immunization of rabbits with Type II bacteria themselves. The reactivity of the antiyeast serum is strictly specific to the Type II variety of Pneumococcus in the sense that it is entirely devoid of antibodies reactive with Type I or III. The results of absorption experiments with both the antiyeast (rabbit) serum and the anti-Type II (horse) serum were the same as those usually obtained in analogous experiments with immunologically related, but not identical, kinds of bacteria. The immunological relationship of the yeast and the Type II pneumococcus is apparently based upon S-anti-S reactions. It represents an example of heterogenetic specificity which is of particular interest because of the wide genetic separation of the pathogenic schizomycete and the saprophytic ascomycete. Data on the individual irregularity in the yeast-agglutinating capacity of serum from non-immunized or "normal" rabbits are presented as experimental facts.

scholarly journals PROPERTIES OF THE TYPE SPECIFIC PROTEINS OF ANTIPNEUMOCOCCUS SERA

1937 ◽  
Vol 66 (4) ◽  
pp. 425-435 ◽  
Author(s):  
Kenneth Goodner ◽  
Frank L. Horsfall
Keyword(s):  
Capsular Polysaccharide ◽  
Horse Serum ◽  
Total Content ◽  
Immune Serum ◽  
Rabbit Serum ◽  
Antibody Activity ◽  
Subsequent Paper ◽  
Type I ◽  
Protective Capacity ◽  
Precipitable Protein

The generally held view has been that in any immune serum only a single antibody would be induced by and react with a single antigen. Were this true the various manifestations of antibody activity should show a quantitative parallelism. It has already been shown (1), however, that with antipneumococcus horse serum the mouse protective potency does not parallel the maximum amount of specifically precipitable protein except within certain well defined groups of antisera. The simplest explanation of this situation is that different horses form antibodies differing in specific protective capacity, but from our studies it seems probable that in any immune serum there may occur a mixture of antibodies which, while directed against the same antigen, possess different protective capacities, different avidities, etc. It would now appear that this latter hypothesis is the more tenable since the experiments here reported indicate the existence of antibodies of various protective potencies in horse antisera. It would not be unreasonable to hold that the antibodies of a single serum represent a series of substances with varying properties. On the basis of the present immunological fractionation experiments, the following deductions seem permissible. 1. Antipneumococcus horse sera must contain at least three, possibly many, antibody substances which react with the capsular polysaccharide. These are: (a) A substance which precipitates upon the addition of a relatively small amount of polysaccharide. This antibody possesses a low protective potency. (b) A substance which is precipitated with intermediate amounts of polysaccharide and which possesses an extremely high protective value. (c) A third substance which is precipitated only with the addition of relatively large amounts of polysaccharide. The protective value of this antibody is very low It may represent a degraded form. 2. With antipneumococcus rabbit serum the situation is somewhat simpler. This is in accord with the fact that with Type I antipneumococcus sera from this species there is a direct proportionality between the amount of specifically precipitable protein and the protective potency of the serum (1). The results with antipneumococcus rabbit serum indicate the existence of at least two antibody substances: (a) An antibody with high protective value which makes up the greater proportion of the total content. (b) A second substance which is precipitated only upon the addition of relatively large amounts of capsular polysaccharide. The existence of this second antibody is not clearly demonstrated by the present findings but the lower protective ratios obtained as greater amounts of antibody are removed probably indicate its existence. This may also represent degraded material. The observations on the antibodies of both horse and rabbit antisera will be supported by experiments with immunochemical fractionation which will be reported in a subsequent paper.

scholarly journals QUANTITATIVE EXPERIMENTS WITH ANTIBODIES TO A SPECIFIC PRECIPITATE

1942 ◽  
Vol 75 (2) ◽  
pp. 135-150 ◽  
Author(s):  
Henry P. Treffers ◽  
Dan H. Moore ◽  
Michael Heidelberger
Keyword(s):  
Horse Serum ◽  
Rabbit Antiserum ◽  
Cross Reaction ◽  
Rabbit Serum ◽  
Type Ii ◽  
Rabbit Antibody ◽  
Serum Albumins ◽  
Normal Horse Serum ◽  
Antigenic Properties ◽  
The Cross

1. Rabbit antisera to a Type II pneumococcus specific precipitate from horse serum were tested with fractions prepared by ultracentrifugation and electrophoresis of normal and immune horse serum. 2. In one instance a rapidly sedimenting protein from normal horse serum had nearly the same quantitative antigenic properties toward the anti-antibody rabbit serum as did the purified pneumococcus antibody solutions previously reported. In another instance a comparable fraction removed only a part of the rabbit antibody. 3. Electrophoretic γ-globulin from an immune horse serum had quantitatively the same antigenic properties as did antibody solutions prepared by salt-dissociation of specific precipitates. 4. Electrophoretic γ-globulin from normal horse serum differed in its antigenic behavior from γ-globulin containing antibody. The data are compared with the antigenic properties of acid and alkali treated pneumococcus specific polysaccharides toward antipneumococcus horse sera. An interpretation in terms of polymers is suggested. 5. The cross-reaction of goat serum γ-globulin against the anti-antibody serum is reported and the extent of the reaction compared with those of goat and horse serum albumins against a rabbit antiserum to the latter.

scholarly journals SEROLOGICAL RELATIONSHIP BETWEEN PNEUMOCOCCUS TYPE I AND AN ENCAPSULATED STRAIN OF ESCHERICHIA COLI

1935 ◽  
Vol 62 (2) ◽  
pp. 281-287 ◽  
Author(s):  
L. A. Barnes ◽  
Eleanor C. Wight
Keyword(s):  
Escherichia Coli ◽  
Horse Serum ◽  
Rabbit Serum ◽  
Type I ◽  
Type B ◽  
Soluble Substance ◽  
Serological Relationship ◽  
Normal Horse Serum ◽  
The Relationship ◽  
Pneumococcus Type

An encapsulated strain of Escherichia coli has been isolated which is hemolytic, pathogenic for mice, and which has served to illustrate further evidence of heterogenetic specificity. The relationship appears to be limited to the serological reactions between the colon organism and Type I antipneumococcic horse serum. Type I antipneumococcic rabbit serum failed to agglutinate the organism and no reactions occurred with Types II and III antipneumococcic horse serums, normal horse serum, and a variety of other immune horse serums. Serum from rabbits immunized with the colon bacillus agglutinated the homologous organism and precipitated its soluble substance, but failed to cause agglutination of Type I pneumococci or to precipitate Type I pneumococcic polysaccharide. The evidence indicates a connection somewhat analogous to that between Type II pneumococcus and Type B Friedländer's bacillus.

scholarly journals IMMUNOLOGICAL STUDIES ON PURE CULTURES OF VARIOUS SPIROCHETES

1917 ◽  
Vol 25 (6) ◽  
pp. 765-788 ◽  
Author(s):  
Hideyo Noguchi ◽  
Seinai Akatsu
Keyword(s):  
Complement Fixation ◽  
Virulent Strain ◽  
Immune Serum ◽  
The Other ◽  
Rabbit Serum ◽  
Complete Suppression ◽  
Normal Rabbit Serum ◽  
Slight Degree ◽  
Group Reaction

Experiments were carried out for the study of culture spirochetes in their relation to various immunity reactions in vitro. Several strains of Treponema pallidum and one each of Treponema calligyrum, Spirochata refringens, Treponema microdentium, and Treponema mucosum were used. Tests were made of immune substances responsible for agglutination, complement fixation, spirocheticidosis, and opsonization. In cases of agglutination and complement fixation, cross titrations were made. 1. In the sera derived from rabbits immunized with various spirochetes agglutinins were demonstrated in varying quantities for the homologous antigens. The amounts of agglutinins developed were considerably higher in the pallidum immune sera than in the other groups. There was no parallelism between the amounts of antigens injected and the amounts of agglutinins developed. 2. Cross titrations among different pallidum strains revealed that the agglutiantion is not necessarily strongest when homologous antigens and immune sera are brought together. 3. On the other hand, the reactions between the immune sera and antigens belonging to different species were sufficiently specific to justify the grouping. 4. Certain degrees of group reactions were observed between the pallidum immune sera and the calligyrum, and occasionally very faintly also between the pallidum and the refringes antigens and vice versa. There was a much more pronounced group reaction between the calligyrum and refringes. The immune serum and antigen of the microdentium showed a slight affinity for the mucosum but none for the pallidum, calligyrum, or refringes, while the mucosum immune serum caused a slight agglutination with many members of the other groups. Hence, it appears that the pallidum is more or less related to the calligyrum, while the affinity between the calligyrum and refringes, and possibly also between the calligyrum and mucosum in a much smaller degree, seems close. The microdentium showed the least relation to any other spirochetes. 5. Titration of agglutinins in the sera obtained 3 months after the cessation of immunization revealed that the agglutinin contents were already greatly reduced, having fallen roughly to 0.01 of the original strenght. The rates of disappearance were irregular in different animals and bore no direct relation to the initial titers. Titration made of the immune sera which had been preserved aseptically in a refrigerator (6°C.) during the same period (3 months) indicated that the original strength of these sera was reduced to about one-tenth. The agglutinins for spirochetes disappear from the rabbit's body much more rapidly than they are reduced in the separated sera by deterioration on standing at 6°C. 6. Titration of the immune sera for complement fixation power showed with a few exceptions, in which there was only slight complement binding, that the titers were high enough to indicate the presence of this principle. The anti-pallidum sera possessed higher average titers than the other immune sera tested with correspondingly homologous antigens. The least active were the anti-refrigens sera. 7. Cross titration of anti-pallidum immune sera for complement fixation showed that a given serum with a high titer for its own strain of antigen was also strong with most of the other strains of the pallidum. Instances occurred also in which the titers with heterologous pallidum antigens fell far below those of the homologous. Group reactions between the different spirochetes) such as the pallidum and the calligyrum, the calligyrum and the refringens, and the microdentium and the mucosum, were also indicated. The mucosum and the pallidum showed a slight degree of group reaction. No anti-pallidum serum fixed complement with the microdentium. 8. The immune sera were tested for their spirochetiddal properties in vitro against the correspondingly specific and heterologous varieties with and without the addition of complement. Many of the anti-pallidum sera killed their own strains. Normal rabbit serum exhibited only a slight degree of inhibition. Without complement, the immune sera caused a considerable reduction in the number or density of colonies, but not a complete suppression of growth. Complement alone had no injurious effect upon the pallidum strains. The antisera for the calligyrum, refringens, and mucosum showed feeble spirocheticidal action, while the antisera for microdentium was stronger. A syphilitic rabbit serum tested against a strain of culture pallidum gave a feeble inhibitory effect. 9. Under the influence of immune sera and complement, the spirochetes undergo within a few hours complete disintegration or granular degeneration. Without complement, they are more powerfully agglutinated, but no disintegration occurs, even after 20 hours, and complement alone has no effect. 10. In the presence of homologous immune serum and complement, the culture pallidum may be ingested by the leukocytes, but phagocytosis is slight, possibly on account of the filamentous nature of the organisms. The spirochetes in such a mixture disintegrate within a few hours, disintegration being especially rapid when the immune leukocytes are used. In the absence of immune serum, phagocytosis is not noticeable, while without complement but in the presence of immune serum and leukocytes, some phagocytosis, without subsequent lysis, occurs. A virulent strain of pallidum, obtained from syphilitic orchitis in a rabbit, exposed to agglutination, lysis, and phagocytosis by an immune serum prepared by means of culture pallidum strains, showed only slight agglutination and phagocytosis but rapid immobilization without disintegration in the presence of complement.

Modeling Endoleaks and Collateral Reperfusion following Endovascular AAA Exclusion

2003 ◽  
Vol 10 (3) ◽  
pp. 424-432 ◽  
Author(s):  
Chuh K. Chong ◽  
Thien V. How ◽  
Geoffrey L. Gilling-Smith ◽  
Peter L. Harris
Keyword(s):  
Stent Graft ◽  
Aortic Pressure ◽  
Type I ◽  
Type Ii ◽  
Pump System ◽  
Type Ii Endoleak ◽  
Type I Endoleak ◽  
The Impact ◽  
Mean Aortic Pressure

Purpose: To investigate the effect on intrasac pressure of stent-graft deployment within a life-size silicone rubber model of an abdominal aortic aneurysm (AAA) maintained under physiological conditions of pressure and flow. Methods: A commercial bifurcated device with the polyester fabric preclotted with gelatin was deployed in the AAA model. A pump system generated physiological flow. Mean and pulse aortic and intrasac pressures were measured simultaneously using pressure transducers. To simulate a type I endoleak, plastic tubing was placed between the aortic wall and the stent-graft at the proximal anchoring site. Type II endoleak was simulated by means of side branches with set inflow and outflow pressures and perfusion rates. Type IV endoleak was replicated by removal of gelatin from the graft fabric. Results: With no endoleak, the coated graft reduced the mean and pulse sac pressures to negligible values. When a type I endoleak was present, mean sac pressure reached a value similar to mean aortic pressure. When net flow through the sac due to a type II endoleak was present, mean sac pressure was a function of the inlet pressure, while pulse pressure in the sac was dependent on both inlet and outlet pressures. As perfusion rates increased, both mean and pulse sac pressures decreased. When there was no outflow, mean sac pressure was similar to mean aortic pressure. In the presence of both type I and type II endoleaks, mean sac pressure reached mean aortic pressure when the net perfusion rate was low. Conclusions: In vitro studies are useful in gaining an understanding of the impact of different types of endoleaks, in isolation and in combination, on intrasac pressure after aortic stent-graft deployment.

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