Alan C. Pipkin

Bio: Alan C. Pipkin is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Schizogony & Plasmodium gallinaceum. The author has an hindex of 6, co-authored 6 publications receiving 202 citations.

The Morphology and Behavior of Living Exoerythrocytic Stages of Plasmodium gallinaceum and P. fallax and Their Host Cells

Abstract: The morphology and behavior of living exoerythrocytic stages of Plasmodium gallinaceum and P. fallax were studied by the use of tissue cultures, phase contrast microscopy, and time-lapse cinephotomicrography. The morphology of exoerythrocytic stages of these two species was essentially that previously observed in fixed, stained material, with the following exceptions: (1) the presence of a filament on one end of the merozoite, (2) the absence of clefts in the cytoplasm of the large schizonts, and (3) the absence of a vacuole-like space around the parasite. The following behavior was observed either directly or in time-lapse sequences: (1) emergence of merozoites from mature schizonts, (2) progressive motility of free merozoites, (3) entry of merozoites, both actively and passively, into host cells, (4) nuclear division in the parasite, (5) the various stages of schizogony, including final production of merozoites, (6) massive infection of host cells, and (7) phagocytosis of merozoites and attempted phagocytosis of mature schizonts by macrophages. Exoerythrocytic stages of P. fallax differed from those of P. gallinaceum in that the merozoites of the former were (1) somewhat more curved in shape and (2) present in fewer numbers in mature schizonts. The use of tissue culture, phase contrast microscopy, and time-lapse cinephotomicrography promises to solve many of the remaining problems concerning exoerythrocytic stages of malarial parasites and their interrelationships with host cells.

The morphology and behavior of living exoerythrocytic stages of Plasmodium gallinaceum and P. fallax and their host cells.

Abstract: The morphology and behavior of living exoerythrocytic stages of Plasmodium gallinaceum and P. fallax were studied by the use of tissue cultures, phase contrast microscopy, and time-lapse cinephotomicrography. The morphology of exoerythrocytic stages of these two species was essentially that previously observed in fixed, stained material, with the following exceptions: (1) the presence of a filament on one end of the merozoite, (2) the absence of clefts in the cytoplasm of the large schizonts, and (3) the absence of a vacuole-like space around the parasite. The following behavior was observed either directly or in time-lapse sequences: (1) emergence of merozoites from mature schizonts, (2) progressive motility of free merozoites, (3) entry of merozoites, both actively and passively, into host cells, (4) nuclear division in the parasite, (5) the various stages of schizogony, including final production of merozoites, (6) massive infection of host cells, and (7) phagocytosis of merozoites and attempted phagocytosis of mature schizonts by macrophages. Exoerythrocytic stages of P. fallax differed from those of P. gallinaceum in that the merozoites of the former were (1) somewhat more curved in shape and (2) present in fewer numbers in mature schizonts. The use of tissue culture, phase contrast microscopy, and time-lapse cinephotomicrography promises to solve many of the remaining problems concerning exoerythrocytic stages of malarial parasites and their interrelationships with host cells.

Invasion of erythrocytes by malaria merozoites

Abstract: An electro-optical system was developed to record microscope images with high resolution at low light intensities The system was used to study the invasion of erythrocytes by malaria merozoites Invasion consists of attachment of the anterior end of the parasite to the erythrocyte, deformation of the erythrocyte, and the entry of the parasite by erythrocyte membrane invagination

Trichomonads Parasitic in Humans

Abstract: 1. Introduction..- 2. Taxonomy and Nomenclature.- 3. Structure.- 4. Immunologic Aspects of Human Trichomoniasis.- 5. Biochemistry of Trichomonas vaginalis.- 6. Nucleic Acid Metabolism in Trichomonas vaginalis.- 7. Cultivation of Trichomonads Parasitic in Humans.- 8. Employment of Experimental Animals in Studies of Trichomonas vaginalis Infection.- 9. Host Cell-Trichomonad Interactions and Virulence Assays Using In Vitro Systems.- 10. Microflora Associated with Trichomonas vaginalis and Vaccination Against Vaginal Trichomoniasis.- 11. Clinical Manifestations of Urogenital Trichomoniasis in Women.- 12. Epidemiology and Clinical Manifestations of Urogenital Trichomoniasis in Men.- 13. Urogenital Trichomoniasis in Children.- 14. Cytopathology and Histopathology of Female Genital Tract in Trichomonas vaginalis Infection.- 15. Pathology of Urogenital Trichomoniasis.in Men.- 16. Laboratory Diagnostic Methods and Cryopreservation of Trichomonads.- 17. Epidemiology of Urogenital Trichomoniasis.- 18. Therapy of Urogenital Trichomoniasis.- 19. Trichomonads Found Outside the Urogenital Tract of Humans.- 20. Symptomatology, Pathology, Epidemiology, and Diagnosis of Dientamoeba fragilis.