Which of the following statements regarding the complement system are true? a. Complement activation yields products which are directly cytotoxic as well as products which act indirectly via activated leukocytes b. Complement products referred to as anaphylatoxins include C1, C3a, C4a, and C5a c. The principal role of C5a is in bacterial opsonization d. The alternative and classical pathways converge proximal to generating the membrane attack complex (C5b-9)

Which of the following statements regarding the complement system are true? a. Complement activation yields products which are directly cytotoxic as well as products which act indirectly via activated leukocytes b. Complement products referred to as anaphylatoxins include C1, C3a, C4a, and C5a c. The principal role of C5a is in bacterial opsonization d. The alternative and classical pathways converge proximal to generating the membrane attack complex (C5b-9)
by

1 Answer

Answer :

Answer: a, d  The complement system is composed of two different but linked sequences, the classic and alternative pathways. The pathways involve serum proteins that act to amplify the inflammatory-immune response as well as to directly mediate tissue injury. Complement activation by either pathway has been associated with a cascade of events, some of which are mediated directly at a physiologic level by complement products and some of which occur indirectly via activated leukocytes. The direct physiologic effects mediated by C3a and C5a, and to a lesser extent C4a, include increased vascular permeability and contraction of smooth muscle. These are key elements of anaphylaxis. C1 is not an anaphylatoxin as it is the initial complement component which binds to antigen-antibody complex to initiate classical pathway activation. C5a acts principally to alter the behavioral characteristics of leukocytes. Effects include enhanced adherence, enhanced chemotactic activity, release of proteinases, and production of toxic metabolites of oxygen. C3, on the other hand, plays a key role in bacterial opsonization, resulting in enhanced phagocytosis of invading microorganisms. The alternative and classical complement pathways converge at the C5 level proximal to generating the membrane attack complex (C5b-9) (Figure 6-3)
by
selected

Related questions

Which of the following statement(s) is/are correct concerning the immunoinflammatory response to shock? a. The anaphylactoxins, C3a and C5a, are products of activation of only the classical pathway of the compliment cascade b. Eicosanoids, such as prostaglandins are stored in platelets and endothelial cells and released in response to inflammatory stimuli c. Thromboxane and PGI2 have similar effects d. Platelet-activating factor can be released by both circulating and fixed tissue cells

Description : Which of the following statement(s) is/are correct concerning the immunoinflammatory response to shock? a. The anaphylactoxins, C3a and C5a, are products of activation of only the classical pathway ... effects d. Platelet-activating factor can be released by both circulating and fixed tissue cells

Last Answer : Answer: d Inflammatory mediators have recently been recognized as playing a significant role in the clinical manifestations and progression of shock and the development ... increased pulmonary vascular resistance, bronchoconstriction, peripheral vasodilatation, and increased vascular permeability

Which of the following statements regarding the alternative complement pathway are true? a. C1, C4 and C2 are involved b. NH3 apparently activates complement via this pathway c. Factors B and D are involved d. Endotoxin activates complement via the alternative pathway

Description : Which of the following statements regarding the alternative complement pathway are true? a. C1, C4 and C2 are involved b. NH3 apparently activates complement via this pathway c. Factors B and D are involved d. Endotoxin activates complement via the alternative pathway

Last Answer : Answer: b, c, d The alternative pathway differs from the classic pathway in that the first steps involving C1, C4 and C2 are bypassed. (See Figure 6-3 previously reproduced.) ... been correlated with impaired renal function and the presence of complement components at the sites of renal injury

In the complement system; a. alternative pathway does not rely on antibody b. C1 is the first enzyme complex in the classical pathway c. both the alternative and classical pathway converge at C3 d. all above

Description : In the complement system; a. alternative pathway does not rely on antibody b. C1 is the first enzyme complex in the classical pathway c. both the alternative and classical pathway converge at C3 d. all above

Last Answer : all above

The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following statement(s) is/are true concerning complement activation? a. The alternate (properdin) pathway of complement activation can occur directly through contact with fungal or bacterial cell wall compounds b. Complement component fragments may serve to decrease vascular permeability c. Excessive complement activation can produce deleterious effects d. Fragments of certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Description : The complement system consists of a series of serum proteins that exist in a quiescent or very low-level state of activation in the uninfected host. Which of the following ... certain complement components serve as chemoattractants to additional cellular components of the host defense mechanism

Last Answer : Answer: a, c, d Complement activation can occur through either classic or alternate (properdin) pathways, both of which eventuate in deposition of terminal complement pathway components on the ... and release of lysosomal enzymes that can directly damage certain target tissues, such as the lung

True statements regarding eicosanoids include which of the following? A. Prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase pathway. B. The vasoconstricting, platelet-aggregating, and bronchoconstricting effects of thromboxane A 2 are balanced by the actions of prostacyclin, which produces the opposite effects. C. Leukotriene synthesis is inhibited by the action of nonsteroidal anti-inflammatory drugs (NSAIDs). D. The principal prostaglandins have a short circulation half-life and exert most of their effects locally.

Description : True statements regarding eicosanoids include which of the following? A. Prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase pathway. B. The vasoconstricting, platelet-aggregating, ... prostaglandins have a short circulation half-life and exert most of their effects locally.

Last Answer : Answer: ABD DISCUSSION: The eicosanoids are a group of compounds arising from the metabolism of arachidonic acid. The prostaglandins and thromboxanes are synthesized via the cyclo-oxygenase ... effects and may be involved in the physiologic responses associated with anaphylactic and septic shock

Fibrinolytic therapy is based on activation of plasminogen, the inactive proteolytic enzyme of plasma that binds to fibrin during the formation of thrombosis. Activation of plasminogen to plasmin results in selective thrombolysis at the fibrin clot surface. Which of the following statement(s) is/are true concerning agents used in thrombolytic therapy? a. Streptokinase is a bacterial protein which is antigenic in humans, resulting in allergic reactions in up to l5% of cases b. Tissue plasminogen activator acts directly on plasmin without an intermediate drug–plasmin complex c. The half-life of urokinase, streptokinase, and TPA all exceed 30 minutes d. Streptokinase is significantly cheaper than urokinase or TPA

Description : Fibrinolytic therapy is based on activation of plasminogen, the inactive proteolytic enzyme of plasma that binds to fibrin during the formation of thrombosis. Activation of plasminogen to plasmin results ... TPA all exceed 30 minutes d. Streptokinase is significantly cheaper than urokinase or TPA

Last Answer : Answer: a, b, d Streptokinase is a bacterial protein produced by group C b-hemolytic streptococci. It is therefore antigenic in humans and can be associated with allergic reaction in ... one agent over the other. Streptokinase however, is markedly less expensive than either urokinase or TPA

Tests of coagulation are used to monitor anticoagulation treatment and detect intrinsic abnormalities in coagulation. Which of the following statement(s) is/are true concerning coagulation tests? a. Prothrombin time (PT) measures both the intrinsic and extrinsic clotting pathways and fibrinogen b. Activated partial thromboplastin time (aPTT) can be used to monitor both oral anticoagulation with Warfarin and intravenous anticoagulation with heparin c. Thrombin clotting time (TCT) is a measurement of the time it takes for exogenously administered thrombin to turn plasma fibrinogen into fibrin clot d. Whole blood activated clotting time (ACT) is a measurement of the ability of whole blood to clot and is used to monitor heparin levels intraoperatively during cardiovascular and peripheral vascu

Description : Tests of coagulation are used to monitor anticoagulation treatment and detect intrinsic abnormalities in coagulation. Which of the following statement(s) is/are true concerning ... is used to monitor heparin levels intraoperatively during cardiovascular and peripheral vascular operations

Last Answer : Answer: a, c, d Coagulation tests include prothrombin time (PT), which measures the intrinsic and extrinsic pathways of fibrinogen production and is the most common method for ... more while for peripheral vascular applications, values of 250 seconds or greater are considered appropriate

Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may be generated from activated neutrophils and during reperfusion following a period of ischemia. C. The deleterious effects of oxidants include lipid peroxidation and cell membrane damage, oxidative damage to DNA, and inhibition of adenosine triphosphate (ATP) synthesis. D. The mechanism of ischemia-reperfusion injury involved the catalytic production of superoxide anion (O 2•) by the enzyme xanthine oxidase.

Description : Which of the following statements are true of oxidants? A. In addition to their pathophysiologic roles in inflammation, injury, and infection, oxidants also have physiologic roles. B. Oxidants may ... involved the catalytic production of superoxide anion (O 2 ) by the enzyme xanthine oxidase.

Last Answer : Answer: ABCD DISCUSSION: Oxidants are reactive oxygen metabolites that have both physiologic and pathophysiologic roles. As potent oxidizing agents, oxidants are involved in cytochrome P ... leukocyte infiltration and activation, causing further tissue damage by the release of cytotoxic proteases

Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) is a major proinflammatory mediator with multiple effects, including regulation of skeletal muscle proteolysis in patients with sepsis or significant injury. C. Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability. D. Tumor necrosis factor alpha (TNF-a), despite its short plasma half-life, appears to be a principal mediator in the evolution of sepsis and the multiple organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Description : Which of the following statements regarding cytokines is incorrect? A. Cytokines act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) ... organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates.

Last Answer : Answer: C DISCUSSION: Cytokines are soluble peptide molecules that are synthesized and secreted by a number of cell types in response to injury, inflammation, and infection. Cytokines, which ... is thought to play a central role in the stress response, particularly in response to endotoxemia

Neutrophil chemotaxis is a fundamental aspect of inflammatory injury in conditions such as the Adult Respiratory Distress Syndrome (ARDS). Neutrophil chemotaxis is directly attributable to which of the following molecules? a. C5a b. TNFa c. LPS d. IL-1 e. ENA-78 (Epithelial Neutrophil Activating Protein)

Description : Neutrophil chemotaxis is a fundamental aspect of inflammatory injury in conditions such as the Adult Respiratory Distress Syndrome (ARDS). Neutrophil chemotaxis is directly attributable to which of the following molecules? ... TNFa c. LPS d. IL-1 e. ENA-78 (Epithelial Neutrophil Activating Protein)

Last Answer : Answer: a, e There is a large collection of peptide, polypeptide and lipid mediators which have chemotactic properties. Although TNF a, IL-1 and LPS were initially reported to have direct ... are several complement-derived peptides. Perhaps, the most potent of these is the short-lived C5a peptide

There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s) is/are true concerning energy converting transport? a. The site of energy conversion and transport in the plasma membrane involves the phospholipid component b. The Na+-K++-ATPase derives energy from hydrolysis of extracellular ATP c. In some systems, energy inherent in the transmembrane ion gradient can be used to drive transport of a second species d. Examples of species transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Description : There are two properties of the cell necessary to maintain nonequilibrium cellular composition; the first is selectivity and the second is energy conversion. Which of the following statement(s ... transported via secondary active transport include hydrogen ions, calcium, amino acids and glucose

Last Answer : Answer: c, d The selectivity of the plasma membrane, although impressive, cannot account for the nonequilibrium composition of living cells. A cell can be maintained in a nonequilibrium state only by ... to drive the transport of a second species such as protons, calcium, amino acids, or glucose

The following are true: a. Ig G crosses the placenta b. thymus gland is responsible for cellular immunity c. C1-9 is used by the alternative complement pathway d. eosinophils are responsible for phagocytosis

Description : The following are true: a. Ig G crosses the placenta b. thymus gland is responsible for cellular immunity c. C1-9 is used by the alternative complement pathway d. eosinophils are responsible for phagocytosis

Last Answer : Ig G crosses the placenta

Which of the following cells or blood elements play a role in the initial phases of wound healing? a. Polymorphonuclear leukocytes (PMNs) b. Platelets c. Monocytes d. Lymphocytes

Description : Which of the following cells or blood elements play a role in the initial phases of wound healing? a. Polymorphonuclear leukocytes (PMNs) b. Platelets c. Monocytes d. Lymphocytes

Last Answer : Answer: a, b, c, d Shortly after the initial injury, the wound is full of debris which is cleared over the next several days by recruited and activated phagocytic cells. ... in the initial hemostatic process as well as releasing chemotactic factors and factors leading to fibroblast proliferation

Which of the following statements about the role of the gut in shock and sepsis are true? A. Selective decontamination of the digestive tract with the use of oral antibiotics has been shown to reduce nosocomial pneumonias and to improve mortality rates. B. Enteral nutrition, as compared with parenteral nutrition, preserves the villus architecture of the gut. C. Gut dysfunction may be an effect of shock, but it may also contribute to the development of MODS by the mechanism of bacterial translocation. D. As compared with parenteral nutrition, enteral nutrition is associated with a reduction in septic morbidity.

Description : Which of the following statements about the role of the gut in shock and sepsis are true? A. Selective decontamination of the digestive tract with the use of oral antibiotics has been ... As compared with parenteral nutrition, enteral nutrition is associated with a reduction in septic morbidity.

Last Answer : Answer: BCD DISCUSSION: The gut has a vital role in the pathophysiology of shock. The splanchnic circulation is very vulnerable to the circulatory redistribution that occurs in shock, thus, gut ... , enteral feeding is more cost effective and is associated with a lower rate of septic morbidity

The following statement(s) is/are true concerning host defense mechanisms to intraabdominal infection. a. Bacterial clearance can occur via translymphatic absorption b. Phagocytic activity and bacterial killing can occur via resident phagocytic cells and an influx of PMNs c. A fibrinogen-rich inflammatory exudate is released into the peritoneal cavity, trapping large numbers of bacteria and other particulate matter d. Perforations of a bowel may be walled off but are seldom sealed by the omentum and other mobile viscera

Description : The following statement(s) is/are true concerning host defense mechanisms to intraabdominal infection. a. Bacterial clearance can occur via translymphatic absorption b. Phagocytic activity and bacterial killing can ... may be walled off but are seldom sealed by the omentum and other mobile viscera

Last Answer : Answer: a, b, c The introduction of microorganisms into the normally sterile peritoneal environment invoke several potent specialized host antimicrobial defense mechanisms. Bacterial clearance, ... the contaminated enteric contents walled off, preventing continued soilage of the peritoneal cavity

Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The pulmonary edema of ARDS occurs in the face of elevated left heart pressures c. The initial physiologic changes of ARDS involve the capillary endothelial cells and the type I pneumocyte d. Mechanisms proposed in the pathogenesis of ARDS include injury from mediators of inflammation elsewhere and from activated cellular elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Description : Which of the following statement(s) is/are true concerning the pulmonary response to shock? a. The acute pulmonary vascular response to shock differs markedly from that of systemic vasculature b. The ... elements e. A decrease in lung compliance may result from the loss of type I pneumocytes

Last Answer : Answer: c, d, e Contributing pathophysiologic processes to the pulmonary manifestations of shock include the pulmonary component of the cardiovascular response, disruption of the normal ... injury from mediators of inflammation elaborated elsewhere, and from activated cellular blood elements

Polymorphonuclear leukocytes (or PMNs) A- can be attracted to the site of an infection following activation of complement B- are derived from bone marrow stem cells C- are a type of phagocyte that can engulf and kill bacteria D- .all of the above

Description : Polymorphonuclear leukocytes (or PMNs) A- can be attracted to the site of an infection following activation of complement B- are derived from bone marrow stem cells C- are a type of phagocyte that can engulf and kill bacteria D- .all of the above

Last Answer : .all of the above

C1 component of classical complement pathway is made up of (A) Complements 1q and 1r (B) Complements 1q and 1s (C) Complements 1r and 1s (D) Complements 1q, 1r and 1s

Description : C1 component of classical complement pathway is made up of (A) Complements 1q and 1r (B) Complements 1q and 1s (C) Complements 1r and 1s (D) Complements 1q, 1r and 1s

Last Answer : Answer : D

Increasing evidence has implicated gram-negative bacterial lipopolysaccharide (LPS endotoxin) as the portion of the gram-negative bacterial cell membrane responsible for many, if not all the toxic effects that occur during gram-negative bacterial sepsis. The following statement(s) is/are true concerning LPS and the host response. a. The LPS molecule can in itself cause physiologic responses similar to that seen during gram-negative bacterial sepsis b. LPS triggers host macrophages to release a variety of cytokines including TNF-a, IL-1a, and IL-1b, IL-6, and IFN-a c. Excessive cytokine production is not associated with detrimental consequences d. TNFa and IL-1b appear to be the primary mediators within the host, exerting deleterious effects on the host when excessive amounts reach the syst

Description : Increasing evidence has implicated gram-negative bacterial lipopolysaccharide (LPS endotoxin) as the portion of the gram-negative bacterial cell membrane responsible for many, if not all the ... host, exerting deleterious effects on the host when excessive amounts reach the systemic circulation

Last Answer : Answer: a, b, d The LPS molecule exerts diverse effects on the mammalian host. Immunologic responses to LPS include nonspecific polyclonal B-cell proliferation, macrophage activation and ... deleterious effects on the host only after large amounts are secreted and reach the systemic circulation

Which of the following statements regarding the transmission of infectious agents through blood transfusions is/are true? A. The transmission rates for human immunodeficiency virus (HIV) have been decreasing progressively since the early 1980s. B. The transmission rates of hepatitis have been decreasing steadily since the 1980s. C. Cytomegalovirus (CMV) is the infectious agent most commonly transmitted in blood. D. Severely immunocompromised patients (such as patients undergoing transplantation) should receive specially screened blood products.

Description : Which of the following statements regarding the transmission of infectious agents through blood transfusions is/are true? A. The transmission rates for human immunodeficiency virus (HIV) ... patients (such as patients undergoing transplantation) should receive specially screened blood products.

Last Answer : Answer: ABCD DISCUSSION: The incidence of both HIV and hepatitis transmitted via blood transfusions has been steadily decreasing since the 1980s. This is related to improved ... , severely compromised patients such as those undergoing transplantation should receive CMV-negative blood products

Which of the following statement(s) is/are true concerning tumor necrosis factor (TNF)? a. TNF is a product of activated macrophages secreted in response to contact with endotoxin or lipopolysaccharide, antibody complexes, or inflammatory stimuli b. The liver and gut appear to be a major source of TNF following hypoperfusion c. Circulating levels of TNF correlate well with severity of tissue injury in shock d. Recently completed clinical trials of anti-TNF antibody in septic patients shows a marked improvement in survival

Description : Which of the following statement(s) is/are true concerning tumor necrosis factor (TNF)? a. TNF is a product of activated macrophages secreted in response to contact with endotoxin or ... completed clinical trials of anti-TNF antibody in septic patients shows a marked improvement in survival

Last Answer : Answer: a, b Tumor necrosis factor (TNF), a protein product of activated macrophages, is secreted in response to contact with endotoxin or lipopolysaccharide, antibody complexes, or ... patients utilizing infusion of monoclonal antibodies to the TNF molecule have shown no overall survival benefit

The following statement(s) is/are true concerning gram-negative bacterial sepsis. a. Mortality due to this condition has almost been eliminated due to therapeutic intervention with antibiotics, aggressive hemodynamic monitoring and fluid resuscitation b. Recent series have noted a decrease in the incidence of this condition c. Predisposing factors include old age, malnutrition, and immunosuppression d. Pseudomonas bacteremia is the most common cause of gram-negative sepsis e. Polymicrobial sepsis is generally considered a more serious problem than sepsis due to a single organism

Description : The following statement(s) is/are true concerning gram-negative bacterial sepsis. a. Mortality due to this condition has almost been eliminated due to therapeutic intervention with antibiotics, aggressive ... sepsis is generally considered a more serious problem than sepsis due to a single organism

Last Answer : Answer: c, e Gram-negative bacterial sepsis is a serious disease process that produces substantial morbidity and mortality in both normal and immunocompromised patients (10% to 20% and ... and most investigators agree that polymicrobial sepsis is more lethal than infection with a single organism

Wounds are classified according to the likelihood of bacterial contamination. Which of the following statement(s) is/are true concerning wound classifications? a. A clean-contaminated wound would be that associated with an elective colon resection with adequate mechanical and antibiotic bowel preparation b. A contaminated wound would include a resection of obstructed bowel with gross spillage of intestinal contents c. In a clean wound, no viscus is entered d. Antibiotic prophylaxis should be administered for all clean-contaminated and contaminated wounds and selectively in patients involving a clean wound

Description : Wounds are classified according to the likelihood of bacterial contamination. Which of the following statement(s) is/are true concerning wound classifications? a. A clean-contaminated wound would ... all clean-contaminated and contaminated wounds and selectively in patients involving a clean wound

Last Answer : Answer: a, b, c, d Wounds are classified under three classes according to the likelihood of bacterial contamination: 1) clean (no viscus is entered; e.g., herniorrhaphy); 2) clean- ... tenet involves cases in which a prosthetic material may be used (artificial joint, heart valve, tissue patch)

As thrombin generation proceeds, the body has natural anticoagulant systems opposing further thrombus formation. Natural anticoagulants include: a. Tissue plasminogen activator (TPA) b. Antithrombin III c. Activated protein C d. Heparin cofactor II

Description : As thrombin generation proceeds, the body has natural anticoagulant systems opposing further thrombus formation. Natural anticoagulants include: a. Tissue plasminogen activator (TPA) b. Antithrombin III c. Activated protein C d. Heparin cofactor II

Last Answer : Answer: b, c, d Just as thrombin generation is the key to coagulation, antithrombin III is the most central anticoagulant proteins. This glycoprotein binds to thrombin, preventing its removal of ... in the body. Therefore, TPA is part of the fibrinolytic system rather than a natural anticoagulant

Mini-dose heparin has been shown to be useful in the prophylaxis of postoperative venous thrombosis. Mechanism(s) by which low-dose heparin is/are thought to protect against venous thrombosis include: a. Enhancement of antithrombin III activity b. A decrease in thrombin availability c. Inhibition of platelet aggregation and subsequent platelet release action d. A mild prolongation of activated partial thromboplastin time

Description : Mini-dose heparin has been shown to be useful in the prophylaxis of postoperative venous thrombosis. Mechanism(s) by which low-dose heparin is/are thought to protect against venous ... aggregation and subsequent platelet release action d. A mild prolongation of activated partial thromboplastin time

Last Answer : Answer: a, b, c Low-dose heparin is thought to protect against venous thrombosis through three different mechanisms. First, antithrombin III activity with its inhibition of activated Factor X is ... release reaction. The standard doses of heparin administered (5000 units bid) does not affect aPTT

The evaluation of a patient scheduled for elective surgery should always include the following as tests of hemostasis and coagulation: A. History and physical examination. B. Complete blood count (CBC), including platelet count. C. Prothrombin time (PT) and activated partial thromboplastin time (APTT). D. Studies of platelet aggregation with adenosine diphosphate (ADP) and epinephrine.

Description : The evaluation of a patient scheduled for elective surgery should always include the following as tests of hemostasis and coagulation: A. History and physical examination. B. Complete blood count ( ... (APTT). D. Studies of platelet aggregation with adenosine diphosphate (ADP) and epinephrine.

Last Answer : Answer: A DISCUSSION: The evaluation of most patients scheduled for elective surgery who do not have a history of significant bleeding disorders is somewhat controversial. An adequate history and ... suspected of having qualitative defects of platelet function (e.g., von Willebrand's disease)

Which of the following statements about the coagulation cascade is/are true? A. The intrinsic pathway of coagulation is the predominant pathway in vivo for hemostasis and coagulation. B. The intrinsic pathway beginning with the activation of factor XII is the predominant in vivo mechanism for activation of the coagulation cascade. C. Deficiencies of factor VIII and IX cause highly significant coagulation abnormalities. D. Deficiencies of factor XII cause severe clinical bleeding syndromes.

Description : Which of the following statements about the coagulation cascade is/are true? A. The intrinsic pathway of coagulation is the predominant pathway in vivo for hemostasis and coagulation. ... coagulation abnormalities. D. Deficiencies of factor XII cause severe clinical bleeding syndromes.

Last Answer : Answer: AC DISCUSSION: Although it was previously held that two somewhat distinct pathways existed for the activation of the coagulation cascade, it is now recognized that the predominant ... bleeding. This further emphasizes the secondary role that the intrinsic pathway plays in coagulation

Which of the following statements are true of the multiple organ dysfunction syndrome (MODS)? A. The “two-hit” model proposes that secondary MODS may be produced when even a relatively minor second insult reactivates, in a more amplified form, the systemic inflammatory response that was primed by an initial insult to the host. B. The systemic inflammatory response syndrome (SIRS), shock due to sepsis or SIRS, and MODS may be regarded as a continuum of illness severity. C. Prolonged stimulation or activation of Kupffer cells in the liver is thought to be a critical factor in the sustained, uncontrolled release of inflammatory mediators. D. The incidence of MODS in intensive care units has decreased owing to increased awareness, prevention, and treatment of the syndrome.

Description : Which of the following statements are true of the multiple organ dysfunction syndrome (MODS)? A. The two-hit model proposes that secondary MODS may be produced when even a relatively ... intensive care units has decreased owing to increased awareness, prevention, and treatment of the syndrome.

Last Answer : Answer: ABC DISCUSSION: MODS is part of a clinical continuum that begins with the systemic inflammatory response syndrome, which is the host's stress response to any major insult such ... pathogenesis of MODS, the incidence of MODS continues to increase without a significant improvement in outcome

Which of the following statement(s) is/are true concerning the role of antibiotics in wound care? a. Systemic antibiotics are indicated for all open wounds b. Bacterial resistance can occur with systemic but not topical antibiotics c. An indication for systemic antibiotic administration is a granulation tissue bacterial count in excess of greater than 105 organisms/gram of tissue on quantitative analysis d. Silver sulfadiazine is useful only for the management of burns

Description : Which of the following statement(s) is/are true concerning the role of antibiotics in wound care? a. Systemic antibiotics are indicated for all open wounds b. Bacterial resistance can occur with ... of tissue on quantitative analysis d. Silver sulfadiazine is useful only for the management of burns

Last Answer : Answer: c The role of antibiotics in wound care is controversial. All open wounds are colonized with bacteria. Only when surrounding tissue is invaded (cellulitis) are systemic antibiotics clearly ... of relevant drug-resistant plasmids in bacteria, and its low cost make it a good choice

The neurohormonal arm of the stress response is well defined. Less is known about the inflammatory arm mediated primarily by cytokines. Which of the following statement(s) is/are true concerning this arm of the surgical stress response? a. Cytokines primarily work locally via direct cell-to-cell communication b. Cytokines are never detectable in the systemic bloodstream c. Cytokines are produced only by immune cells attracted to the site of injury d. Cytokine release may stimulate the release of other cytokines leading to an important cascade of events

Description : The neurohormonal arm of the stress response is well defined. Less is known about the inflammatory arm mediated primarily by cytokines. Which of the following statement(s) is/are true ... Cytokine release may stimulate the release of other cytokines leading to an important cascade of events

Last Answer : Answer: a, d Cytokines, which are produced at the site of injury by endothelial cells and by diverse immune cells throughout the body, also occupy a pivotal position in the stress response ... act as hormones and spill over into the systemic circulation and become detectable in the bloodstream

Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following statement(s) is/are true concerning antimicrobial classes? a. Penicillins and cephalosporins share the compound structure of a b-lactam ring which binds to bacterial division plate proteins b. Tetracyclines and macrolides such as erythromycin inhibit bacterial ribosomal activity and therefore protein synthesis c. Aminoglycosides act in a similar fashion to tetracyclines and therefore are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Description : Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following ... are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Last Answer : Answer: a, b, d Penicillins, cephalosporins, and monobactams possess a b-lactam ring of some type and act to bind bacterial division plate proteins, thus inhibiting cell wall ... act in different mechanisms to inhibit protein synthesis, therefore two agents in combination act synergistically

The use of antibiotics can be based on either the clinical course of a patient without the benefit of well-defined microbiologic data (empiric therapy), or targeted at specific identified pathogens once sensitivity reports are available (directed therapy). The following statement(s) is/are true concerning these therapies. a. The issue of toxic side effects of antibiotics is only important in dealing with emperic therapy b. Single agent therapy is generally inferior to specific multi-drug therapy (aminoglycoside plus an antianaerobic agent) for the treatment of secondary bacterial peritonitis due to appendicitis, diverticulitis, penetrating gastrointestinal injury, or anastomotic leak c. With the empiric use of antibiotics, a diligent search for the septic source should be undertaken and co

Description : The use of antibiotics can be based on either the clinical course of a patient without the benefit of well-defined microbiologic data (empiric therapy), or targeted at ... which polymicrobial infection is identified, specifically-directed treatment for the predominant organism is satisfactory

Last Answer : Answer: c The use of empiric therapy without the benefit of well-defined microbiologic data is appropriate when there is sufficient clinical evidence to support the diagnosis such that it would ... components of the infection if the body site is such that these microorganisms may be present

Glucose overload results in increased CO 2 production. Which of the following statements are true? A. In patients with respiratory insufficiency, administration of glucose as a principal calorie source is contraindicated. B. In patients with pulmonary infection and sepsis, calorie support should consist of 95% fat and 5% glucose. C. In Askanazi's study, increased CO 2 production and difficulty in weaning was associated only with pronounced overfeeding. D. CO 2 production should be measured in most patients who are supported by respirators in intensive care units and are receiving nutritional support.

Description : Glucose overload results in increased CO 2 production. Which of the following statements are true? A. In patients with respiratory insufficiency, administration of glucose as a principal calorie ... who are supported by respirators in intensive care units and are receiving nutritional support.

Last Answer : Answer: C DISCUSSION: Few papers have excited as much interest as that by Askanazi, Kinney, and co-workers, which demonstrated that glucose calories given to patients with severe respiratory ... the caloric requirement and glucose for the remainder, without much fear of excessive CO 2 production

Which of the following statements about extracellular fluid are true? A. The total extracellular fluid volume represents 40% of the body weight. B. The plasma volume constitutes one fourth of the total extracellular fluid volume. C. Potassium is the principal cation in extracellular fluid. D. The protein content of the plasma produces a lower concentration of cations than in the interstitial fluid. E. The interstitial fluid equilibrates slowly with the other body compartments.

Description : Which of the following statements about extracellular fluid are true? A. The total extracellular fluid volume represents 40% of the body weight. B. The plasma volume constitutes one fourth ... the interstitial fluid. E. The interstitial fluid equilibrates slowly with the other body compartments.

Last Answer : Answer: B DISCUSSION: The total extracellular fluid volume represents 20% of body weight. The plasma volume is approximately 5% of body weight. Sodium is the principal cation. The ... fluid and cerebrospinal fluid, the majority of the interstitial fluid exists as a rapidly equilibrating component

State the role of activated complex in a reaction and state the relation with energy of activation.

Description : State the role of activated complex in a reaction and state the relation with energy of activation.

Last Answer : Ans.: When the colliding reactant molecules possess the kinetic energy equal to energy of activation then the configuration of atoms of the species at this state is different from the reactants as well as ... barrier means the activated complex is difficult to form and it is a slow reaction.  

The alternate complement pathway doesn’t involve (A) Antigen-antibody complex (B) Complement 3 (C) Factors B and D (D) Membrane attack unit

Description : The alternate complement pathway doesn’t involve (A) Antigen-antibody complex (B) Complement 3 (C) Factors B and D (D) Membrane attack unit

Last Answer : Answer : A

The formation of _____ by_____ directly lyses and kills pathogens. a. Membrane Attack Complexes, complement b. Inflammation, lymph nodes c. antibodies, plasma cells d. Plasma cells, B cells

Description : The formation of _____ by_____ directly lyses and kills pathogens. a. Membrane Attack Complexes, complement b. Inflammation, lymph nodes c. antibodies, plasma cells d. Plasma cells, B cells

Last Answer : a. Membrane Attack Complexes, complement

Interleukin-6 is recognized as the cytokine primarily responsible for the alteration in hepatic protein synthesis recognized as the acute phase response. Which of the following statement(s) is/are true concerning acute phase protein response to surgical stress? a. Glucocorticoid hormones inhibit this response b. Proteins such as albumin and transferrin which serve in serum transport are generally increased in this response c. Examples of acute phase proteins include fibrinogen and C-reactive protein d. In general, the physiologic role of acute phase proteins are to reduce the systemic effects of tissue damage

Description : Interleukin-6 is recognized as the cytokine primarily responsible for the alteration in hepatic protein synthesis recognized as the acute phase response. Which of the following statement(s) is/are true ... physiologic role of acute phase proteins are to reduce the systemic effects of tissue damage

Last Answer : Answer: c, d IL-6 is now recognized at the cytokine primarily responsible for the alteration in hepatic synthesis recognized as the acute phase response. Glucocorticoid hormones augment ... that generally inhibit the tissue destruction that is associated with the local initiation of inflammation

Which of the following statements regarding neutrophils are true? a. The neutrophil undergoes final maturation after release into the circulation b. Patients with chronic granulomatous disease have a defective neutrophil H-oxidase system c. Neutrophil killing of bacteria is achieved by oxidants, proteinases and cationic proteins d. The normal human neutrophil circulates in the blood for 7–10 days

Description : Which of the following statements regarding neutrophils are true? a. The neutrophil undergoes final maturation after release into the circulation b. Patients with chronic granulomatous disease have a defective ... proteins d. The normal human neutrophil circulates in the blood for 7-10 days

Last Answer : Answer: b, c The neutrophil is a migratory phagocytic cell that defends the host against bacteria and eliminates necrotic tissue. The neutrophil matures in the bone marrow and is ... phagocytose bacteria, they are unable to kill the intracellular microbes and chronic, unresolved infections result

Which of the following statements regarding TNFa are true? a. TNFa has a marked procoagulant effect b. Passive immunization of patients with neutralizing antibodies to TNFa improves survival from multi-organ system failure c. TNFa upregulates E-selectin expression d. The most potent known stimulus for TNFa production and release is IL-1

Description : Which of the following statements regarding TNFa are true? a. TNFa has a marked procoagulant effect b. Passive immunization of patients with neutralizing antibodies to TNFa improves survival from multi-organ ... expression d. The most potent known stimulus for TNFa production and release is IL-1

Last Answer : Answer: a, c TNFa has a marked procoagulant effect on endothelial cells, precipitating intravascular thrombosis. TNFa causes endothelial cells to release procoagulant activity (tissue factor), ... to produce TNFa, however the most potent stimulus for TNFa production and release is endotoxin

Answer: e The role of nutritional support in the cancer patient remains an important component of overall therapy. Preoperative nutritional support should be given only to those patients who do not require an emergency operation and who have severe weight loss (> 15% of pre-illness body weight) and a serum albumen < 2.9 mg%. Preoperative nutrition (enteral or parenteral) should not be given for longer than 7 to 10 days. Enteral nutrition is always the preferred route of feeding cancer patients if the GI tract is functional. There are several benefits of using the bowel lumen for nutrient delivery. The trophic effects of enteral feeding on small bowel mucosa have been well described. The integrity of the mucosal lining is maintained and it may provide an effective barrier to intraluminal

Description : Answer: e The role of nutritional support in the cancer patient remains an important component of overall therapy. Preoperative nutritional support should be given only to those patients who ... of bowel rest; this atrophy is not reversed by currently available total parenteral nutrition solutions

Last Answer : Which of the following hormones can be expected to be released as part of the stress response? a. Antidiuretic hormone (ADH) b. Aldosterone c. Insulin d. Epinephrine nswer: a, b, d ... This hormone has the exact opposite effect of insulin, which promotes glucose storage and uptake by the cells

Intracellular organelles involved with protein synthesis include: a. Mitochondria b. Endoplasmic reticulum c. Golgi complex d. Lysosomes

Description : Intracellular organelles involved with protein synthesis include: a. Mitochondria b. Endoplasmic reticulum c. Golgi complex d. Lysosomes

Last Answer : Answer: b, c Mitochondria are the major source of energy production in eukaryotic cells. The endoplasmic reticulum is the network of interconnected membranes forming closed vesicles, ... containing acid hydrolytic enzymes that degrade polymers such as proteins, carbohydrates, and nucleic acids

The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages may become activated and secrete cytokines c. Macrophages serve as phagocytic cells in the tissues but not within the bloodstream d. Polymorphonucleocytes (PMNS) are normally present in only small numbers within the tissue and enter an area of infection through diapedesis

Description : The following statement(s) is/are true concerning cellular defense mechanisms. a. Macrophages function solely as antigen processing cells in the initial reaction to exposure to an antigen b. Macrophages ... in only small numbers within the tissue and enter an area of infection through diapedesis

Last Answer : Answer: b, d A wide variety of cell types serve to provide host defense at several levels. Macrophages act as the initial antigen processing cell that serves to ... through diapedesis after chemotactic stimuli are excluded by macrophages, bacterial breakdown products, and complement activation

In the nutritional support of patients with cancer, which of the following statements is/are true? A. Nutritional support benefits the patient's lean body mass but does not enable the tumor to grow. B. In experimental animals, the growth of implanted tumors is directly proportional to the amount of calories and protein supplied. C. Prospective randomized trials of nutritional support utilizing chemotherapy and radiation therapy have revealed benefits to patients receiving total parenteral nutrition. D. Studies of nutritional support for patients with cancer about to undergo surgery revealed decreased morbidity and mortality, especially morbidity from sepsis.

Description : In the nutritional support of patients with cancer, which of the following statements is/are true? A. Nutritional support benefits the patient's lean body mass but does not enable ... with cancer about to undergo surgery revealed decreased morbidity and mortality, especially morbidity from sepsis.

Last Answer : Answer: B DISCUSSION: The problem with the patient with cancer is a very vexing one. Clearly, one of the metabolic effects of cancer, cachexia, affects patients in the last quartile ... undoubtedly reveal that there are certain nutrients that tumors require, which probably should be best avoided

Which of the following activates Hageman factor in blood clotting? B A. Kinins B. Negatively charged surfaces C. Complement C5a D. Positively charged collagen

Description : Which of the following activates Hageman factor in blood clotting? B A. Kinins B. Negatively charged surfaces C. Complement C5a D. Positively charged collagen

Last Answer : Negatively charged surfaces

Which of the following statements regarding endothelial cells in acute inflammation are true? a. Endothelial cells are characterized by phenotypic homogeneity b. Specific patterns of receptor expression regulate leukocyte adherence c. Endothelial cell nitric oxide generation regulates regional blood flow and leukocyte adhesion d. Endothelial cells may be capable of phagocytosis

Description : Which of the following statements regarding endothelial cells in acute inflammation are true? a. Endothelial cells are characterized by phenotypic homogeneity b. Specific patterns of receptor expression ... blood flow and leukocyte adhesion d. Endothelial cells may be capable of phagocytosis

Last Answer : Answer: b, c, d Endothelial cells are increasingly recognized to be phenotypically heterogeneous. Specific receptor molecules are expressed at various sites where they help to direct lymphocytes and ... rather, they possess the ability to direct and focus many aspects of an inflammatory event

Which of the following statements regarding angiogenesis are true? a. Angiogenesis is a seminal biologic event with clinical relevance limited to its effect upon tumor growth b. C-X-C chemokines regulate angiogenesis c. PF-4 has angiogenic properties d. Sites of atherosclerosis demonstrate chronic angiogenic activity

Description : Which of the following statements regarding angiogenesis are true? a. Angiogenesis is a seminal biologic event with clinical relevance limited to its effect upon tumor growth b. C-X-C ... c. PF-4 has angiogenic properties d. Sites of atherosclerosis demonstrate chronic angiogenic activity

Last Answer : Answer: b, d An important component of tissue repair and wound healing is the process of angiogenesis. This normal, physiologic process is a local, transient event which is ... between these factors may govern overall angiogenic potential in a variety of physiological and pathophysiological states

Which of the following statements regarding fibroblasts and their function in wound healing are true? a. IL-1 has both inhibitory and promotional effects on fibroblast growth b. TNFa stimulates fibroblast collagen synthesis c. IL-1 and TNFa have opposite effects on the healing of bone d. In human clinical trials, EGF (epithelial growth factor) has been demonstrated to accelerate epidermal regeneration in cutaneous wounds

Description : Which of the following statements regarding fibroblasts and their function in wound healing are true? a. IL-1 has both inhibitory and promotional effects on fibroblast growth b. TNFa ... EGF (epithelial growth factor) has been demonstrated to accelerate epidermal regeneration in cutaneous wounds

Last Answer : Answer: a, d IL-1 appears to be important in the process of normal wound repair. IL-1 has been shown to stimulate skin fibroblast and keratinocyte growth, as well as ... that recombinant EGF enhances keratinocyte migration. EGF is also a potent chemoattractant for granulation tissue fibroblasts

Which of the following statements regarding transforming growth factor b (TGF-b) are true? a. TGF-b expression is autoregulated b. TGF-b enhances collagen synthesis c. TGF-b inhibits extracellular matrix production d. TGF-b may inhibit or promote cellular proliferation

Description : Which of the following statements regarding transforming growth factor b (TGF-b) are true? a. TGF-b expression is autoregulated b. TGF-b enhances collagen synthesis c. TGF-b inhibits extracellular matrix production d. TGF-b may inhibit or promote cellular proliferation

Last Answer : Answer: a, b, d TGF-b appears to be one of the key cytokines in control of tissue repair. TGF-b is strongly chemotactic for neutrophils, T cells, monocytes, and fibroblasts. ... TGF-b stimulates the proliferation of densely plated human marrow fibroblasts, but is inhibitory at high concentrations