Robert H. Black

The effect of anti-malarial drugs on Plasmodium falciparum (New Guinea strains) developing in vitro

1. 1. A method is described which has been used to study the effects of drugs on trophozoites of P. falciparum (New Guinea strains) growing in vitro 2. 2. The effects of sera containing various anti-malarial drugs—paludrine, atebrin, sontochin (SN6911), M4430, resochin (SN7618), plasmoquine, quinine, sulphadiazine and sulphamerazine—on these parasites are described. 3. 3. Atebrin, sontochin, resochin and quinine were observed to cause arrest of development and degeneration of ring and amoeboid forms. 4. 4. Paludrine and M4430 exerted their lethal effect on the early schizonts. 5. 5. The sulphonamides caused degeneration of divided schizonts. 6. 6. Plasmoquine had inconstant or only minor effects. 7. 7. The degenerating forms seen when paludrine is used in vitro with P. falciparum and in vivo with P. vivax are similar. 8. 8. The mode of action of anti-malarial drugs is discussed.

Experimental studies of the potentiation of proguanil and pyrimethamine by dapsone using Plasmodium berghei in white mice.

An accurate system with stringent criteria has been established to test antimalarial drugs and drug combinations against Plasmodium berghei in mice. Minimum effective doses for a number of antimalarial drugs have been determined when used in this system. Considerable potentiation of the activity of pyrimethamine and to a somewhat less extent of proguanil by dapsone has been demonstrated. The need to extend studies of these combinations to the parasites of human malaria is discussed in terms of establishing a safe chemoprophylactic regime in the presence of drug-resistant strains of parasites.

Enlargement of the liver due to malaria in natives of the South West Pacific area.

Abstract 1. (1) Observations are presented of the liver size of 4,047 indigenous natives in various areas of the South-West Pacific Area with varying degrees of malarial endemicity. 2. (2) An examination was made of two groups of labourers imported from Wallis Island where malaria is not endemic. There was a significantly higher incidence of palpable livers in the group which had been exposed to and suffered from malaria, when no malaria suppressive drugs were being taken, than in the other group which had taken suppressive drugs from the commencement of exposure to infection. 3. (3) In the three areas described in this paper 4,047 natives have been examined in localities where the degree of malaria varied from non-endemic to holoendemic. The changes seen in liver size in all these peoples as a group are discussed. A definite correlation was found between the amount of malaria and the size of livers in the community of endemic areas although no difference was demonstrated between communities in hyper- and holoendemic areas. 4. (4) Liver enlargement with a different age-group distribution was found on an island where malaria is not endemic. 5. (5) It is pointed out that there are no signs of malignant malnutrition in these people and that other endemic diseases which commonly cause liver enlargement are not present in these areas in the South-West Pacific. Further study is required before the pathogenesis of the hepatomegaly due to endemic malaria becomes clear.

Leishman's stain adapted for use with histological sections.

(1948). Leishmans Stain Adapted for Use with Histological Sections. Annals of Tropical Medicine & Parasitology: Vol. 42, No. 1, pp. 52-53.

Comparison of the liver and spleen sizes in a community in Netherlands New Guinea suffering from malaria of a high degree of endemicity.

Abstract 1. (1) Comparison of the spleen and liver sizes in a community in the Nimboran area of Netherlands New Guinea has shown significant positive correlations in the various age-groups considered, ranging upwards from two years. 2. (2) It is concluded that, in the malarious areas of the South-West Pacific, the liver enlarges as well as the spleen and that, in an area of high malarial endemicity, the liver enlargement is proportionate to that of the spleen.