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________ are semisynthetic derivatives that have replaced artemisinins, which are particularly well suited for the treatment of severe P.
falciparum malaria and now play a key role in the combination therapy of drug-resistant infections.
________ are semisynthetic derivatives that have replaced artemisinins, which are particularly well suited for the treatment of severe P. falciparum malaria and now play a key role in the combination therapy of drug-resistant infections.
Please match the following:
Please match the following:
Resistance to isoniazid usually results from = an inactivating mutation in the mycobacterial enzyme catalase-peroxidase, which converts isoniazid into its antimycobacterial form Resistance to antimycobacterial agents in general = results from chromosomal mutations Resistance to pyrazinamide is generally due to = mutations in the pyrazinamidase gene, which result in the inability to convert the prodrug into its active form Ethambutol resistance most often results from = mutations in the arabinosyl transferase gene, some of which cause overexpression of the target enzyme
Arrange the following events of the mechanism of action of chloroquine
(alphabetical) with respect to their sequential occurence (numerical).
Arrange the following events of the mechanism of action of chloroquine (alphabetical) with respect to their sequential occurence (numerical).
Accumulation of unpolymerized heme metabolite leads to active oxidative membrane damage and is toxic to the parasite = 4 Chloroquine thus poisons the parasite by preventing the detoxification of a toxic product of hemoglobin catabolism = 5 As a result, protonated chloroquine accumulates to high concentrations inside the parasite’s food vacuole, where it binds to ferriprotoporphyrin IX and inhibits the polymerization of the heme metabolite = 3 Once inside the acidic environment of the parasite’s food vacuole, chloroquine is rapidly protonated, making it to unable to diffuse out of the vacuole = 2
Chloroquine is highly effective against which of the following erythrocytic forms of
plasmodial species/strains?
Chloroquine is highly effective against which of the following erythrocytic forms of plasmodial species/strains?
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Chloroquine-resistant plasmodia accumulate less chloroquine inside food vacuoles
than chloroquine-sensitive plasmodia do. Which of the following statements are
correct? SATA
Chloroquine-resistant plasmodia accumulate less chloroquine inside food vacuoles than chloroquine-sensitive plasmodia do. Which of the following statements are correct? SATA
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Each tuberculous lesion in an infected lung can contain
108 bacteria. The frequency of mutants resistant to any single
antimycobacterial drug is about 1 in 106 bacteria. What would be
the frequency of mutants resistant to the coadministration of four
antimycobacterial drugs?
Each tuberculous lesion in an infected lung can contain 108 bacteria. The frequency of mutants resistant to any single antimycobacterial drug is about 1 in 106 bacteria. What would be the frequency of mutants resistant to the coadministration of four antimycobacterial drugs?
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______ itself does not accumulate appreciably in tissues during
long-term administration, except in erythrocytes, where its concentration is about
three times that in plasma.
______ itself does not accumulate appreciably in tissues during long-term administration, except in erythrocytes, where its concentration is about three times that in plasma.
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Because of the protection conferred by their walls, the____________ of E
histolytica or G lamblia can survive days to weeks in the external environment and are responsible for transmission
Because of the protection conferred by their walls, the____________ of E histolytica or G lamblia can survive days to weeks in the external environment and are responsible for transmission
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Resistant mutants are present in all microbial populations at approximately 1
in 106 and are rapidly selected out if _____________ is used as a single drug, especially in a patient with active infection
Resistant mutants are present in all microbial populations at approximately 1 in 106 and are rapidly selected out if _____________ is used as a single drug, especially in a patient with active infection
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The nitro group of ______________ is reduced by ferredoxin and the
resulting products are responsible for disrupting the DNA helical structure which
leads to inhibition of nucleic acid synthesis and causing strand breakage;
___________is amebicidal, bactericidal, trichomonacidal.
The nitro group of ______________ is reduced by ferredoxin and the resulting products are responsible for disrupting the DNA helical structure which leads to inhibition of nucleic acid synthesis and causing strand breakage; ___________is amebicidal, bactericidal, trichomonacidal.
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Hypnozoites are formed in the life cycle of which of the following plasmodial
species?
Hypnozoites are formed in the life cycle of which of the following plasmodial species?
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It has been established that electrons required for metronidazole activation are
released from pyruvate by the activity of __________________ and transferred to
the drug by a low-redox-potential carrier, ferredoxin.
It has been established that electrons required for metronidazole activation are released from pyruvate by the activity of __________________ and transferred to the drug by a low-redox-potential carrier, ferredoxin.
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Match the following antitubercular drugs (numerical) with their most common side or adverse effects (alphabetical) as given below (scroll down to see). Use only the UPPER CASE alphabet (A-D) for your answer
Match the following antitubercular drugs (numerical) with their most common side or adverse effects (alphabetical) as given below (scroll down to see). Use only the UPPER CASE alphabet (A-D) for your answer
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Metronidazole is indicated for the treatment of
Metronidazole is indicated for the treatment of
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Excystation occurs in which of the following organs:
Excystation occurs in which of the following organs:
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When a malarial parasite infects a red blood cell, its presence can be detected by the existence
of a parasite protein on the cell’s surface. The immune system can then learn to recognize this
protein and develop weapons to eliminate the infected red blood cells. Which of the following
statements are correct with regard to malarial parasites’ ability to fool our immune system in
recognizing and eliminating the infected RBC? SELECT ALL THAT APPLY.
When a malarial parasite infects a red blood cell, its presence can be detected by the existence of a parasite protein on the cell’s surface. The immune system can then learn to recognize this protein and develop weapons to eliminate the infected red blood cells. Which of the following statements are correct with regard to malarial parasites’ ability to fool our immune system in recognizing and eliminating the infected RBC? SELECT ALL THAT APPLY.
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What is the mechanism of non-bloody diarrhea caused by Giardia Lamblia?
What is the mechanism of non-bloody diarrhea caused by Giardia Lamblia?
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Recurrent malaria due to immunodeficiency, such as from corticosteroids, stress,
or chemotherapy differs from the type that is usually seen in the
immunocompetents. It is because the organisms did not come from the hypnozoite
stage, but rather from an erythrocytic stage. This type of malaria is which of the
following?
Recurrent malaria due to immunodeficiency, such as from corticosteroids, stress, or chemotherapy differs from the type that is usually seen in the immunocompetents. It is because the organisms did not come from the hypnozoite stage, but rather from an erythrocytic stage. This type of malaria is which of the following?
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Patients with active tuberculosis and without a history of prior therapy are started:
Patients with active tuberculosis and without a history of prior therapy are started:
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Peripheral neuropathy is due to competitive inhibition by INH of pyridoxine in
neurotransmitter synthesis and can be prevented by ______________ supplementation
Peripheral neuropathy is due to competitive inhibition by INH of pyridoxine in neurotransmitter synthesis and can be prevented by ______________ supplementation
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Prolonged medication with suppressive doses occasionally causes all the following
side effects. Which of the following could lead to a medical emergency?
Prolonged medication with suppressive doses occasionally causes all the following side effects. Which of the following could lead to a medical emergency?
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Pyrazinamide is a prodrug; it must be converted to its active form, pyrazinoic acid,
by the enzyme pyrazinamidase. It acts by
Pyrazinamide is a prodrug; it must be converted to its active form, pyrazinoic acid, by the enzyme pyrazinamidase. It acts by
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The mechanism of action of Isoniazid is to:
The mechanism of action of Isoniazid is to:
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The mechanism of action of Ethambutol is to:
The mechanism of action of Ethambutol is to:
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When initially introduced, chloroquine was a first-line drug used against all types of
malaria; however, it is now ineffective against most strains of P. falciparum in
Africa, Asia, and South America. This is predominantly because of the following
reasons: SATA
When initially introduced, chloroquine was a first-line drug used against all types of malaria; however, it is now ineffective against most strains of P. falciparum in Africa, Asia, and South America. This is predominantly because of the following reasons: SATA
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Which are the five first-line agents used to treat tuberculosis?
Which are the five first-line agents used to treat tuberculosis?
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Which of the following statements are correct about Rifampin? SATA (select all
four)
Which of the following statements are correct about Rifampin? SATA (select all four)
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Which of the following statements are correct regarding Isoniazid? SATA (select
all three)
Which of the following statements are correct regarding Isoniazid? SATA (select all three)
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Which of the following is the mechanism of action of chloroquine?
Which of the following is the mechanism of action of chloroquine?
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Which of the following statements are correct about Atovaquone? SATA
Which of the following statements are correct about Atovaquone? SATA
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Which of the following drugs is a tissue schizonticide used to prevent relapse of
Pasmodium vivax infections?
Which of the following drugs is a tissue schizonticide used to prevent relapse of Pasmodium vivax infections?
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Match the following qualifying antimalarial drugs for prevention in travelers (numerical) with their
corresponding situations (alphabetical) as given below (scroll down to see). Use only the UPPER CASE alphabet (A-D) for your answer
Match the following qualifying antimalarial drugs for prevention in travelers (numerical) with their corresponding situations (alphabetical) as given below (scroll down to see). Use only the UPPER CASE alphabet (A-D) for your answer
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Study Notes
Antimalarial Drugs
- Artemisinin derivatives are used for severe P.falciparum malaria and drug-resistant infections.
- Chloroquine is highly effective against erythrocytic forms of plasmodial species/strains.
Chloroquine Mechanism of Action
- Chloroquine accumulates in food vacuoles, inhibiting heme polymerization.
- Chloroquine-resistant plasmodia accumulate less chloroquine inside food vacuoles.
Tuberculosis
- Each tuberculous lesion can contain 10^8 bacteria.
- Frequency of mutants resistant to a single antimycobacterial drug is about 1 in 10^6 bacteria.
- The frequency of mutants resistant to the coadministration of four antimycobacterial drugs is (1 in 10^6)^4.
Antimicrobial Drugs
- Metronidazole is amebicidal, bactericidal, and trichomonacidal.
- The nitro group of metronidazole is reduced by ferredoxin, disrupting DNA helical structure.
Plasmodial Species
- Hypnozoites are formed in the life cycle of Plasmodium vivax.
Malaria Immune System
- Malarial parasites can be detected by a parasite protein on the cell's surface.
- The immune system can recognize and eliminate infected red blood cells.
- Malarial parasites can fool the immune system by switching surface proteins.
Giardia Lamblia
- The mechanism of non-bloody diarrhea caused by Giardia Lamblia is the disruption of brush border enzymes.
Recurrent Malaria
- Recurrent malaria due to immunodeficiency differs from the type seen in immunocompetents.
- It is due to the organisms coming from the erythrocytic stage, not the hypnozoite stage.
Antitubercular Drugs
- Patients with active tuberculosis are started on a combination of four antitubercular drugs.
- Pyrazinamide is converted to pyrazinoic acid by pyrazinamidase and acts by inhibiting mycolic acid synthesis.
- The mechanism of action of Isoniazid is to inhibit mycolic acid synthesis.
- The mechanism of action of Ethambutol is to inhibit arabinogalactan synthesis.
- Five first-line agents used to treat tuberculosis are Isoniazid, Rifampin, Ethambutol, Pyrazinamide, and Streptomycin.
- Rifampin is a bactericidal drug that inhibits RNA synthesis and is effective against both intracellular and extracellular bacteria.
- Isoniazid is a bactericidal drug that inhibits mycolic acid synthesis and is effective against both intracellular and extracellular bacteria.
Antimalarial Drugs
- Atovaquone is a prophylactic drug that inhibits electron transport in the parasite.
- Primaquine is a tissue schizonticide used to prevent relapse of Pasmodium vivax infections.
- Qualifying antimalarial drugs for prevention in travelers include Chloroquine, Mefloquine, Doxycycline, and Atovaquone.
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Learn about semisynthetic derivatives that have replaced artemisinins in the treatment of severe P. falciparum malaria. Discover their role in combination therapy for drug-resistant infections.
