The importance of parasite load in the killing ofPlasmodium vinckeiin mice treated withCorynebacterium parvumor alloxan monohydrate

Parasitology ◽  
1984 ◽  
Vol 89 (3) ◽  
pp. 417-424 ◽  
Author(s):  
F. E. G. Cox ◽  
Stephanie M. Millott
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Parasite Load ◽  
Corynebacterium Parvum ◽  
Specific Immunity ◽  
Pre Treatment ◽  
Alloxan Monohydrate ◽  
High Parasitaemias ◽  
Plasmodium Vinckei

SUMMARYMice pre-treated withCorynebacterium parvumand later challenged withPlasmodium vinckeibecome infected but do not die whereas control mice do. When pre-treated mice were challenged with 1, 10, 1 × 102, 1 × 104, 1 × 105or 1 × 106parasites, the pre-patent periods correlated directly with the number of parasites injected, but the subsequent parasitaemias reached similar levels. This suggests that parasite killing, resulting from pre-treatment withC. parvum, is not triggered until the parasite load has reached a particular threshold. The injection of alloxan monohydrate, which brings about the release of toxic oxygen inter mediates thought to be involved in non-specific immunity, has little effect onP. vinckeiinfections until the parasitaemia is relatively high. This indicates that oxygen-mediated parasite killing also does not occur until the parasitaemia has reached a particular threshold. It is suggested that it is only at relatively high parasitaemias that the factors involved in parasite killing are able to enter the infected red blood cells.

scholarly journals Detection of short-chain carbonyl products of lipid peroxidation from malaria-parasite (Plasmodium vinckei)-infected red blood cells exposed to oxidative stress

1988 ◽  
Vol 249 (1) ◽  
pp. 63-68 ◽  
Author(s):  
G D Buffinton ◽  
N H Hunt ◽  
W B Cowden ◽  
I A Clark
Keyword(s):  
Lipid Peroxidation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Radical Scavenger ◽  
Parasite Plasmodium ◽  
Infected Rbcs ◽  
Carbonyl Products ◽  
Plasmodium Vinckei

Reversed-phase h.p.l.c. was used to detect 2,4-dinitrophenylhydrazine-reactive carbonyl products, which excludes malonaldehyde, in malaria-parasite (Plasmodium vinckei)-infected murine red blood cells (RBCs). A number of alkanals, 4-hydroxyalk-2-enals and alka-2,4-dienals were tentatively identified by comparison with authentic standards. The formation of 4-hydroxynon-2-enal, deca-2,4-dienal and hexanal was greater in P. vinckei-infected RBCs than in their uninfected counterparts and was increased by the presence of t-butyl hydroperoxide. Several of these aldehydes have previously been shown to be toxic to various types of cells, including P. falciparum, in vitro. The iron chelator desferrioxamine and the free-radical scavenger butylated hydroxyanisole inhibited the formation of these aldehydes. These experiments demonstrate that products of lipid peroxidation other than malonaldehyde are formed during the exposure of malaria-infected RBCs in vitro to drugs that generate reactive oxygen species and have anti-parasitic activity. The formation of products of this type during the natural course of malaria infection may have implications for the mechanisms underlying intra-RBC parasite death and the tissue damage associated with the disease.

Heterologous immunity between piroplasms and malaria parasites: the simultaneous elimination of Plasmodium vinckei and Babesia microti from the blood of doubly infected mice

Parasitology ◽  
1978 ◽  
Vol 76 (1) ◽  
pp. 55-60 ◽  
Author(s):  
F. E. G. Cox
Keyword(s):  
Malaria Parasite ◽  
Babesia Microti ◽  
Common Mechanism ◽  
Malaria Parasites ◽  
Corynebacterium Parvum ◽  
Heterologous Immunity ◽  
Pre Treatment ◽  
Plasmodium Vinckei ◽  
Simultaneous Elimination

SummaryMice which have recovered from infections with the avirulent piroplasm Babesia microti are also resistant to challenge with the virulent malaria parasite Plasmodium vinckei. In mice infected with P. vinckei before the peak of the B. microti infection the numbers of malaria parasites in the blood increase until that peak and are then eliminated at the same time as the piroplasms. In mice infected with P. vinckei at or after the peak there is no apparent multiplication and the malaria parasites begin to disappear from the blood immediately. The malaria parasites in doubly infected mice show signs of degeneration similar to those seen in mice pre-treated with Corynebacterium parvum and it is suggested that a common mechanism exists in homologous and heterologous immunity and in immunity following pre-treatment with C. parvum or BCG.

Reduced Arteriosclerotic Plaque Thrombus Formation

1981 ◽  
Author(s):  
M Dujovny ◽  
N Kossovsky ◽  
J-M Loubeau ◽  
R Segal ◽  
D Nelson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Thrombus Formation ◽  
White Blood Cells ◽  
Control Group ◽  
X Rays ◽  
Aspirin 650Mg ◽  
Calcium Deposits ◽  
Pre Treatment ◽  
Cell Fragments

Sixty surgical patients with cerebrovascular accidents and angiographically diagnosed carotid plaques were divided into two groups: .1) pre-treatment with aspirin (650mg/day) and dipyridamol (25mg/tid) (42 patients); 2) no treatments (18 patients). The control group consisted of 10 autopsy of patients dying for unrelated cause.SEM examination of the endarterectomy plaque revealed intact red blood cells in 12 of 42 pre-treated and 18 of 18 untreated specimens; degenerating red blood cells and cell fragments (24/42, 18/18); fibrin (24/42, 18/18) and white blood cells (15/42, 18/18). These were frequently enmeshed in large surface thrombi. Cholesterol crystals (6 μm) were matted on the plaque surface (12/42, 15/18), and spherical globules averaging 3 to 10 μm sporadically blanketed the surface (6/42, 6/18). Plaque from the asymptomatic controls was smaller and less thrombotic. Energy dispersive analysis x-rays (EDAX) of the inner surface of all 70 specimens (50 years old +) revealed surface calcium deposits and nodules in 18 of the surgical cases (12/42, 6/18), and diffuse calcium deposits in 6 controls.Treatment with aspirin and dipyridamol significantly reduces plaque thrombosis.

The adaptation of three isolates ofBabesia divergensto continuous culture in rat erythrocytes

Parasitology ◽  
1991 ◽  
Vol 103 (2) ◽  
pp. 165-170 ◽  
Author(s):  
N. Ben Musa ◽  
R. S. Phillips
Keyword(s):  
Red Blood Cells ◽  
Continuous Culture ◽  
Blood Cells ◽  
Calf Serum ◽  
The Other ◽  
Foetal Calf Serum ◽  
Rat Erythrocytes ◽  
Rpmi Medium ◽  
Babesia Divergens ◽  
High Parasitaemias

Three isolates ofBabesia divergenshave been cultured continuously for 6 months in rat erythrocytes using the candle jar technique (Trager & Jensen, 1976). One isolate was already rat-adapted, the other two became adapted to rats through continuous culture in rat erythrocytes. Parasites were cultured in rat erythrocytes in RPMI medium supplemented with 20% foetal calf serum. The highest parasitaemia obtained was 35% and multiparasitization of red blood cells was often observed. Cultures ofB. divergensremained infective to splenectomized rats. Cultures with high parasitaemias contained a large number of extracellular merozoites. When separated from the red blood cells, these extracellular merozoites retained their infectivity.

Hemoglobin crystals of the red blood cells in the human renal cortex: electron microscopic observations of the renal lithiasis

1978 ◽  
Vol 36 (2) ◽  
pp. 480-481
Author(s):  
Kosuke Ueda ◽  
Hiroto Washida ◽  
Nakazo Watari
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Renal Cortex ◽  
Uranyl Acetate ◽  
Osmic Acid ◽  
Renal Lithiasis ◽  
Electron Microscopic ◽  
Hemoglobin C ◽  
First Case ◽  
Ultrathin Sections

IntroductionHemoglobin crystals in the red blood cells were electronmicroscopically reported by Fawcett in the cat myocardium. In the human, Lessin revealed crystal-containing cells in the periphral blood of hemoglobin C disease patients. We found the hemoglobin crystals and its agglutination in the erythrocytes in the renal cortex of the human renal lithiasis, and these patients had no hematological abnormalities or other diseases out of the renal lithiasis. Hemoglobin crystals in the human erythrocytes were confirmed to be the first case in the kidney.Material and MethodsTen cases of the human renal biopsies were performed on the operations of the seven pyelolithotomies and three ureterolithotomies. The each specimens were primarily fixed in cacodylate buffered 3. 0% glutaraldehyde and post fixed in osmic acid, dehydrated in graded concentrations of ethanol, and then embedded in Epon 812. Ultrathin sections, cut on LKB microtome, were doubly stained with uranyl acetate and lead citrate.

Densitometric Identification of Primitive Erythroblasts After Reaction With Diaminobenzidine

1973 ◽  
Vol 31 ◽  
pp. 328-329
Author(s):  
John A. Trotter
Keyword(s):  
Red Blood Cells ◽  
Analytical Method ◽  
Blood Cells ◽  
Guinea Pigs ◽  
Specific Protein ◽  
Visual Examination ◽  
Hemoglobin Synthesis ◽  
Peroxidatic Activity ◽  
Small Density

Hemoglobin is the specific protein of red blood cells. Those cells in which hemoglobin synthesis is initiated are the earliest cells that can presently be considered to be committed to erythropoiesis. In order to identify such early cells electron microscopically, we have made use of the peroxidatic activity of hemoglobin by reacting the marrow of erythropoietically stimulated guinea pigs with diaminobenzidine (DAB). The reaction product appeared as a diffuse and amorphous electron opacity throughout the cytoplasm of reactive cells. The detection of small density increases of such a diffuse nature required an analytical method more sensitive and reliable than the visual examination of micrographs. A procedure was therefore devised for the evaluation of micrographs (negatives) with a densitometer (Weston Photographic Analyzer).

Scanning electron microscopy of erythrophagocytosis by Entamoeba histolytica trophozoites

1992 ◽  
Vol 50 (1) ◽  
pp. 880-881
Author(s):  
Victor Tsutsumi ◽  
Adolfo Martinez-Palomo ◽  
Kyuichi Tanikawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Red Blood Cells ◽  
Entamoeba Histolytica ◽  
Causative Agent ◽  
Blood Cells ◽  
Protozoan Parasite ◽  
Complex Phenomenon ◽  
Great Capacity ◽  
Scanning Electron

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis in man. The trophozoite or motile form is a highly dynamic and pleomorphic cell with a great capacity to destroy tissues. Moreover, the parasite has the singular ability to phagocytize a variety of different live or death cells. Phagocytosis of red blood cells by E. histolytica trophozoites is a complex phenomenon related with amebic pathogenicity and nutrition.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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