Purification and some properties of carbonic anhydrase from Elephas trogontherii (Steppe elephant) bone.

Four isoenzymes of carbonic anhydrase (CA) were purified from Elephas Irogontherii (steppe elephant) bone (approx 0.3-0.5 million years old) from different locations (outer peripheral, cytosolic, inner peripheral and integral) using Sepharose 4B-L-tyrosine sulphanilamide affinity chromatography and their kinetics properties were investigated and compared with known CA isoenzymes. The purification degree of CAs was monitored by SDS-PAGE. Purification fold for outer peripheral, inner peripheral, cytosolic and integral CA was 395.6, 652.8, 1091 and 429.3 and the molecular mass (as determined by gel filtration chromatography) was 37, 36, 35, and 39 kDa, respectively. The optimal temperature for isozymes was 10-20, 30, 30 and 60 degrees C and optimal pH- was between 7.5-11, 7.5-10, 7.5-10 and 7.5 respectively. K(m) values (at optimum pH and 20 degrees C) for p-nitrophenyl acetate as substrate were 4.83, 6.80, 4.525 and 3.86 mM and the Vmax values for the same substrate were 0.00097, 0.0149, 0.00249 and 0.00072 micromol/L*min, respectively. I50 values of isoenzymes for the inhibitors of CA - sulphanilamide, KSCN, acetazolamide and NaN3 were also determined.

Haemolytic potential of three chemotherapeutic agents and aspirin in glucose-6-phosphate dehydrogenase deficiency

The potential haemolytic effect of three chemotherapeutic drugs and aspirin was tested in vitro by gluthathione stability tests. Blood was collected from the local population of Basra, Iraq where previous studies had found a high frequency of glucose-6-phosphate dehydrogenase [G6PD] deficiency. Primaquine, chloramphenicol and sulfanilamide caused significant concentration-dependent reductions of glutathione levels in G6PD-deficient red cells when compared to normal red cells. Acetylsalicylic acid had no effect on glutathione level. The G6PD-deficient erythrocytes behaved as previously reported, probably due to similar patterns in the distribution of its variants. Studies on each local variant are warranted and new drugs should be tested for haemolytic potential prior to their introduction in areas where the deficiency is common

p-Aminobenzene sulphonyl morpholine, compound 82/208 a new anticonvulsant agent.

p-Aminobenzene sulphonyl morpholine, compound 82/208, was evaluated for acute toxicity and anticonvulsant action in mice against tonic seizures induced by supramaximal electroshock and pentylene tetrazole and strychnine induced seizures and for its effect on blood pressure and respiration in cat. Diphenyl hydantoin (DPH) was used as reference standard. Compound 82/208 exhibited anticonvulsant activity against electroshock induced seizures and PTZ induced tonic seizures in mice. The compound had several distinct advantages over DPH in experimental evaluation in mice.

Tratamento da paracoccidioidomicose: estudo retrospectivo de 500 casos. II - Avaliaçäo dos resultados terapêuticos com sulfanilamídicos, anfotericina B, associaçäo sulfametoxazol/trimetoprim, cetoconazol e miconazol / Treatment of paracoccidioidomycosis; retrospective: retrospective study of 500 cases. II - Evaluation of therapeutic results with sulfonamides, amphotericin B, ketoconazole and miconazole

Säo analisados rretrospectivamente 500 pacientes com paracoccidioidomicose antendidos no Hospital Evandro Chagas da Fundaçäo Oswaldo Cruz, Rio de janeiro, no período de 1960 a 1986. Os resultados ao término do tratamento com o emprego dos sulganilamídicos, anfotericina B, associaçäo sulfametoxazol/trimetoprim, cetoconazol e miconazol mostraram eficácia semelhante. A sulfamidoterapia curou a doença, principalmente da forma clínica tipo adulto; a anfotericina B, eficaz em todas as formas clínicas da doença, mostrou-se comparativamente melhor quando complementadas com sulfanilamídicos ou imidazólico do que a aplicaçäo isolada. A associaçäo sulfametoxazol/trimetoprim cura a doença, mas näo foi útil nos casos resistentes aos sulfamídicos. O cetoconazol foi eficáz, inclusive em casos resistentes aos outros tratamentos; encontramos os piores resultados na forma clínica tipo juvenil e o miconazol cura a doença na forma clínica tipo adulto. As drogas foram bem toleradas mas em todos os casos tratados com a anfotericina B ocorreram efeitos cerebrais

Epidemiology of emergence and spread of drug-resistant falciparum malaria in Southeast Asia.

In Southeast Asia the medicated salt project of Pailin, on the Kampuchea-Thai border, demonstrated that drug resistance, especially chloroquine resistance, can develop when a large population of P. falciparum parasites is exposed to intense transmission under intense drug pressure. The selection of resistant parasites being activated by the introduction of non-immune groups. Emergence of drug resistance was the result of continuous and prolonged mass exposure of P. falciparum to pyrimethamine and chloroquine resulting in the selection of resistant mutants. This selection was associated with multiple exposures of the parasites to much higher drug doses, during repeated passages through the non-immune hosts, increasing the degree of resistance. Resistances spread to the receptive areas of Kampuchea and other neighbouring countries through the movements of the temporary migrants who, by then, had become carriers infected with drug resistant falciparum parasites. The rapid and early spread of chloroquine resistance in A. balabacensis areas was not a coincidence but the result of the biological advantages of this species complex in relation to malaria transmission. In Australasia the medicated salt project carried out in Irian Jaya, on the border with Papua New Guinea, also resulted in the development of drug resistance in P. falciparum.

Biochemical aspects of drug action and resistance in malaria parasites.

Biochemical aspects of action of antifolates and 4-aminoquinolines and their resistance in the malaria parasites are reviewed, with emphasis on pyrimethamine and chloroquine respectively. Resistance to pyrimethamine has been shown to be associated with either an increase in the amount of parasite dihydrofolate reductase or a reduced affinity of the enzyme for drug binding, in line with the presence of a distinctive pathway for folate metabolism. The theories for drug synergism in the folate pathway are discussed with respect to resistance to pyrimethamine and its combination with sulpha drugs. The biochemical basis for chloroquine resistance is still unclear, reflecting incomplete understanding of its mechanism of action. Data implicating the role of haemozoin and other components as a putative chloroquine receptor of the parasites are reviewed, and possible explanations for resistance are discussed.

In vitro sensitivity of Plasmodium falciparum to sulfadoxine and pyrimethamine.

An in vitro microtechnique of Rieckmann et al., (1978) modified by Yisunsri and Rieckmann (1980) using 3 media; Waymouth, Waymouth plus 10% human serum, and RPMI was assessed to determine the sensitivity of P. falciparum to sulfadoxine, pyrimethamine and its combination. The study confirmed the synergism between sulfadoxine and pyrimethamine. There was no interaction between media and drug tested. MIC1 and MIC2 of sulfadoxine in different media showed significant difference (p less than 0.001). No significant difference was observed in MIC1 and MIC2 of pyrimethamine in the three media used (p greater than 0.05). For sulfadoxine-pyrimethamine combination, MIC1 and MIC2 in Waymouth alone and plus 10% human serum showed no significance (p greater than 0.05) while in RPMI showed positive correlation (p less than 0.001). MIC1 might be more applicable for clinical evaluation than MIC2. At present Waymouth medium with 5% patient serum, is considered to be the most suitable for testing sensitivity of malarial parasites.

Mefloquine-pyrimethamine-sulfadoxine combination delays emergence of mefloquine resistant Plasmodium falciparum in continuous culture.

The efficacy of mefloquine against Plasmodium falciparum in continuous culture was studied. The development of mefloquine resistance in P. falciparum was significantly inhibited by a combination of mefloquine, pyrimethamine and sulfadoxine. By contrast, more resistant variants were selected in continuous culture without drug pressure or with pyrimethamine-sulfadoxine pressure. The most mefloquine resistant variants were selected by step-wise increases in mefloquine pressure.

The effect of sulphadoxine/pyrimethamine on gametocytes in falciparum malaria.

A study of the effect of sulphadoxine/pyrimethamine (Fansidar) on P. falciparum's gametocytes in peripheral blood was carried out in Western Thailand. One group of 77 patients with asexual form P. falciparum sensitive to Fansidar were followed weekly to detect the appearance and the duration of gametocytes in peripheral blood after Fansidar treatment on the basis of thick blood film examination. Another group of 14 patients with sexual form P. falciparum was not given any antimalarial treatment and also followed up weekly. No significant difference of average duration of detectable gametocytes was observed between the groups. The average number of days that gametocytes appeared after asexual form in patients receiving treatment was the same as in the untreated group. It is unlikely that Fansidar has the stimulating effect on gametocytogenesis as previously reported.

Cross resistance of pyrimethamine and sulfadoxine to their related compounds in Plasmodium falciparum.

Cross resistance of pyrimethamine and amethopterin, sulfadoxine and the other sulfonamides in Plasmodium falciparum culture lines was studied. Our results indicate some evidence of a cross resistance between pyrimethamine to amethopterin a drug sharing the same mode of action but never been used as an antimalarial before. Studies on sulfonamides revealed that the minimal inhibitory concentration for sulfadoxine was lower than for sulfadiazine and sulfisoxasole, and that a cross resistance between sulfadoxine and the other sulfonamides may not occur.