P. falciparum

The success of quinine inspired the search for other antimalarials. The greatest impetus for the development of synthetic dmgs came this century when the two World Wars intermpted the supply of cinchona bark to the combatants. A stmcturally related 4-quinolinemethanol is mefloquine (65, Lariam [51773-92-3]) which now serves as an effective alternative agent for chloroquine-resistant P. falciparum. This is a potent substance that requires less than one-tenth the dose of quinine to effect cures. There are some untoward side effects associated with this dmg such as gastrointestinal upset and dizziness, but they tend to be transient. Mefloquine is not recommended for use by those using beta-blockers, those whose job requires fine coordination and spatial discrimination, or those with a history of epilepsy or psychiatric disorders. A combination of mefloquine with Fansidar (a mixture of pyrimethamine and sulfadoxine) is known as Fansimef but its use is not recommended. Resistance to mefloquine has been reported even though the compound has not been in wide use. 

Quinacrine (49) is an acridine that was used extensively from the mid-1920s to the end of World War 11. It acts much like chloroquine and is reasonably effective. Because it causes the skin to turn yellow and, in high doses, causes yellow vision, the dmg is no longer in use as an antimalarial. Pyronaridine (77), a 1-azaacridine developed in China, appears to be effective against mefloquine-resistant, but not entirely against chloroquine-resistant, strains of P falciparum. 

Four different protozoa of the genus Plasmodium -P. falciparum, P. vivax, P. ovale and P malariae - can cause malaria. P. falciparum is the most virulent, being responsible for virtually all fatal malaria cases. Humans are infected by a feeding female Anopheles mosquito (Fig. 2). The clinical symptoms of malaria are associated with the development of the parasite within human red blood cells, while the liver stages remain asymptomatic. The following dtugs (in alphabetical order) are currently in use for the treatment of malaria [5]. 

P. malariae), P. falciparum is responsible for the most severe form. At particular risk of developing severe malaria-associated pathology are the non-immune, including tourists and, in endemic areas, children and pregnant women during first pregnancy. 

Bfx and Fx derivatives have been evaluated against the parasites Trypanosoma cruzi (T. cruzi), which is responsible for American Trypanosomiasis and Plasmodium falciparum (P. falciparum) responsible for Malaria. 

Fig. 11 Sulfonyl Fxs and its deoxygenated analogues evaluated as anti-P. falciparum agents...

Malaria is transmitted by the bites of the Anopheles mosquitoes which introduce into the bloodstream one of four species of sporozoites of the plasmodia (Plasmodium falciparum, P. ovale, P. vivax or P. malariae). Initial symptoms of malaria are nonspecific and may resemble influenza and include chills, headache, fatigue, muscle pain, rigors, and nausea. The onset of the symptoms is between 1 to 3 weeks following exposure. Fever may appear 2 to 3 days after initial symptoms and may follow a pattern and occur every 2 or 3 days (P. vivax, P. ovale and P. malariae). Fever with P. falciparum can be erratic and may not follow specific patterns. It is not unusual for patients to have concomitant infections with P. vivax and P. falciparum. Falciparum malaria must always be regarded as a life-threatening medical emergency. 

The distribution of the various species of malaria is not well defined but P. vivax is reported to be prevalent in the Indian subcontinent, Central America, North Africa, and the Middle East, whereas P. falciparum is predominantly in Africa (including sub-Saharan Africa), both East and West Africa, Haiti, the Dominican Republic, the Amazon region of South America, Southeast Asia, and New Guinea. Most P. ovale infections occur in Africa, while the distribution of P. malariae is worldwide.7 Most infections in the United States are reported in American travelers, recent immigrants, or immigrants who have visited... 

P. falciparum malaria is a life-threatening emergency. Complications include hypoglycemia, acute renal failure, pulmonary edema, severe anemia (high parasitism), thrombocytopenia, heart failure, cerebral congestion, seizures, coma, and adult respiratory distress syndrome. 

In an uncomplicated attack of malaria (for all plasmodia except chloroquine-resistant P. falciparum and P. vivax), the recommended regimen is chloroquine 600 mg (base) initially, followed by 300 mg (base) 6 hours later, and then 300 mg (base) daily for 2 days.3 In severe illness or falciparum malaria, patients should be admitted to an acute care unit and quinidine gluconate 10 mgsalt/kg... 

Alternatives Doxycycline (oral) 1 00 mg daily Greater than or equal to 8 years of age 2 mg/kg (maximum 100 mg) Effective for mefloquine-resistant P. falciparum Start 1-2 days before departure, continue through stay in endemic area, and continue regimen for 4 weeks after returning... 

Exchange transfusion that may be required in patients with P. falciparum malaria in whom parasitemia may be between 5% and 15% remains a questionable modality. Either peritoneal or hemodialysis may be indicated in renal failure. 

When advising potential travelers on prophylaxis for malaria, be aware of the incidence of chloroquine-resistant P. falciparum malaria and the countries where it is prevalent. In patients who have P. vivax or P. ovale malaria (note that some patients can have P. falciparum and one of these species), following the treatment of the acute phase of malaria and screening for glucose-6-phosphate dehydrogenase deficiency, patients should receive a regimen of primaquine for 14 days to ensure eradication of the hypnozoite stage of P. vivax or P. ovale. For detailed recommendations for prevention of malaria go to www.cdc.gov/travel/. 

Acute P. falciparum malaria resistant to chloroquine should be treated with intravenous quinidine via central venous catheter and fluid status and the electrocardiogram (ECG) should be monitored closely. 

Hypoglycemia that is associated with both P. falciparum and quinidine administration, should be checked every... 

Figure 8.4 Positive ion direct atmospheric pressure LD mass spectrum of in vitro grown P. falciparum parasites. Protocol C is used for sample preparation estimated number of parasites deposited is approximately 103. A commercially available AP LD quadrupole ion trap (LCQ) system is used.19,20 Typical laser beam spot diameter is 0.5 mm acquisition time is approximately 20 s LCQ inlet capillary temperature -200°C.

In the first LDMS-based detection of malaria in human subjects (unpublished), lOOpl P. falciparum or P. v/vax-infected blood samples, grouped into three different parasitemia ranges—low (10-150 parasites/pl), mid (2 x 103 parasites/pl), and high (25 x 103-60 x 103 parasites/pl)—have been examined using both sample preparation protocols. Parasitemia levels in these samples were previously determined independently for each sample by optical microscopy examination of blood smears. The LDMS data clearly indicate that... 

Figure 8.6 Positive ion LD TOF mass spectra of P. falciparum parasite sample (upper trace), and a control (uninfected blood) sample (lower trace). Protocol D is used for sample preparation. Both samples—in vitro cultured P. falciparum parasites in whole blood, and the whole blood control—are diluted to 5% hematocrit (10-fold) in PBS buffer. In the infected sample the estimated number of deposited parasites per sample well is approximately 100. A commercial LD TOF system is used, and both spectra are normalized to the same (40 mV) detector response value. Each trace represents the average of one hundred single laser shot spectra obtained from linear scanning of an individual well (no data smoothing). The characteristic fingerprint ions of detected heme in the upper trace are denoted.

P. falciparum proteome Ammonium acetate Biphasic LCQ DECA SEQUEST (Florens et al., 2002)... 

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