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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In one area of the northern savanna of Nigeria the proportional frequency of the Burkitt lymphoma in childhood cancers was 39 percent. The age, sex and clinical expression of the tumour were similar to the well described pattern in Ibadan in the southern forest belt. The BL can therefore be regarded as "endemic" in this area, although its frequency is probably less than that recorded in the south. The possibility of a differing epidemiological pattern of P. falciparum malaria being responsible for this finding is discussed.
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PMID:The Burkitt lymphoma in the northern savanna of Nigeria. 746 82

Immobilized metal-ion affinity partitioning (IMAP) is shown to be useful as a preliminary screening test and for the separation of different cell populations based upon recognition of the differences in the proteins on cell surfaces. The feasibility of using IMAP to segregate a spectrum of normal human cells (red blood cells, lymphocytes and fibroblasts) from their counterpart pathological cells has been demonstrated. A clear segregation between normal and sickle-cell anemia red blood cells (RBC), or malaria (Plasmodium vivax) infected RBCs was obtained. Further, the partition differences were found to depend on the nature and the concentrations of metal used. Cells from breast cancer and those from the lung adenocarcinoma showed differences in their partition pattern as compared to normal fibroblasts when PEG-IDA-M(II) was added to the phase system. Maximum differences between the three cell populations were observed in the presence of 10% PEG-IDA-Ni(II). Normal lymphocytes and Burkitt's lymphoma cells (Raji and Namalwa cell lines) were shown to partition differently in the presence of PEG-IDA-M(II) in the phase system. Normal lymphocytes could be distinguished from the Burkitt's lymphoma cell lines in all three phases (top, interface and bottom), in the presence of 10% PEG-IDA-Ni(II) in the system. These differences in the partition behavior could mainly be attributed to the density, surface exposure and micro-environment of histidine residues of cell membrane-associated proteins. These data, along with those obtained for normal and pathological human cells show that IMAP could be a simple and versatile tool for the segregation and study of cells.
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PMID:Segregation of normal and pathological human red blood cells, lymphocytes and fibroblasts by immobilized metal-ion affinity partitioning. 759 55

From the survey that first identified cancer effects of foetal irradiation and related sources has come support for the following hypotheses: (1) competing causes of death for childhood cancers include abortions (solid tumours) and infections (RES neoplasms); (2) the forms taken by RES neoplasms vary with the nature and intensity of indigenous infections; (3) ideal conditions for developing diffuse RES neoplasms (leukaemia) include the gross immunological incompetence caused by trisomy 21; (4) the unusually localised RES neoplasms found in children who have survived repeated attacks of malaria (Burkitt lymphoma and chloroma) are probably the result of these children having exceptionally high levels of passive as well as active immunity; and (5) when teratogenic effects of in utero mutations include faulty erythropoiesis as well as faulty leucopoiesis, infections are not the only rival causes of death.
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PMID:Childhood cancers and competing causes of death. 786 38

In this study the presence of Epstein-Barr virus (EBV) carrying B lymphocytes in different B-cell subpopulations from peripheral blood was determined by spontaneous outgrowth which gives rise to lymphoblastoid cell lines. In healthy seropositive adults, the EBV-carrying B cell was predominantly within the IgM- and IgD-positive but not the IgG-positive subpopulations. Furthermore, these B lymphocytes were in the low-density (large cell) Percoll fraction. The IgM- and IgD-positive B cell phenotype suggests the EBV-carrying B cells to be circulating virgin B cells recently released from the bone marrow. These B cells have an estimated life span of only 6-8 weeks suggesting that long-term EBV persistence in the body may be the result of infection of a more primitive B-cell type. Similar experiments were carried out in children with acute malaria from the Gambia, West Africa, where Burkitt lymphoma (BL) is endemic in order to determine whether a population of EBV-carrying B cells could be identified which had a similar phenotype to the BL cell. The EBV-carrying B cells in this patient group were also found in the IgM-positive, IgG-negative B-cell subpopulation. The majority of these cells were found in the low-density (large cell) Percoll fraction although in some patients a proportion was derived from the high-density (small cell) fraction. This cellular phenotype is not representative of a BL cell.
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PMID:Epstein-Barr virus-carrying B cells are large, surface IgM, IgD-bearing cells in normal individuals and acute malaria patients. 795 72

The etiology of Burkitt's lymphoma (BL) includes three factors which operate in a stepwise fashion: (1) the ubiquitous Epstein-Barr virus (EBV) which possesses oncogenic potential when it infects infants or very young children; (2) malaria which specifically depresses cytotoxic T cell clones controlling the polyclonal proliferation of EBV-infected B cells in the host; and (3) chromosomal translocations activating the c-myc oncogene which in turn induces uncontrolled B cell proliferation. The unravelling of such a multistep carcinogenic process has shaken a number of well-established dogmas of our time.
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PMID:The etiology of Burkitt's lymphoma and the history of the shaken dogmas. 801 47

At least three genetic changes are known to contribute to the genesis of Burkitt's lymphoma (BL): the Ig/myc translocation, the presence of Epstein-Barr virus (EBV) in the vast majority of the endemic and a minority of sporadic tumors, and a p53 mutation, present in approximately 60% of the BL-derived lines. Activation of c-myc by juxtaposition to Ig sequences is a universal common denominator in endemic and sporadic EBV positive and negative BLs. It acts by preventing the cell from leaving the cycling compartment and by facilitating immune escape. EBV probably acts by expanding the target cell population at risk and prolonging its life span. This, together with the malaria co-factor, would increase the risk of the translocation accident. The p53 mutation may be essential for the continued growth of the tumors where it occurs, since introduction of wild-type p53 leads to their apoptotic death.
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PMID:Multistep evolution of B-cell-derived tumors in humans and rodents. 827 58

The Epstein-Barr Virus (EBV) is consistently found in tumor cells of Burkitt's lymphoma (BL) endemic in central Africa and malaria is considered a pathogenic cofactor. In contrast, fewer than 20% of BL cases occurring in Western countries are EBV-associated. We have investigated 54 BL cases from Bahia, a tropical region of Northeast Brazil, for expression of EBV gene products by in situ hybridization and immunohistology and performed typing of the EBV by polymerase chain reaction. Ten pediatric BL cases from Germany served as controls. New cases of malaria were not observed in the period and area of our study. Small nuclear EBV encoded transcripts, EBER, were found in tumor cells of 47 of 54 Brazilian cases (87%) but in only 2 of 10 German cases (20%). Type I latency of the EBV infection with absence of EBV-encoded proteins LMP1 and EBNA2 was found in 45 of 47 of the EBER-positive Brazilian cases. In two cases, occasional LMP1-containing tumor cells were found in the neighborhood of small Schistosoma mansoni granulomas and scars. BHLF1 transcripts associated with lytic EBV infection could be detected in few cells in 3 of the 40 EBER-positive Brazilian cases investigated. EBV type A was found in the majority of Brazilian BL cases (20 of 30 A-type, 7 of 30 B-type, and 3 of 30 not amplifiable). Our results indicate that the association of Bahian BL with EBV, but not the regional prevalence of malaria, is similar to endemic African BL. In two cases, type II latency was found in association with schistosomiasis, suggesting a role of this parasitosis in the induction of an EBV expression pattern that is unusual for BL. Because chronic schistosomiasis is associated with elevated Th2 cytokine expression resulting in reduced cell-mediated cytotoxicity, it seems possible that altered local immunity is responsible for this peculiar phenotype.
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PMID:Expression of Epstein-Barr virus-gene products in Burkitt's lymphoma in Northeast Brazil. 973 Oct 79

This study was carried out on 100 young patients with Burkitt's tumour from March 1994 to September 1995. They were clinically examined and biopsied at the Dental out patient Clinic, Mulago Hospital, Kampala, Uganda. The tumour was demonstrated as a single or multiple lesion involving the jawbones. It had a male/female ratio 2:1, the peak incidence had occurred at 4-6 years of age. The malaria, as an endemic disease in this country as well as malnutrition are factors which may induce viral factors involved in this formidable tumour.
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PMID:Burkitt's lymphoma: a recent clinical and histopathologic study in Uganda. 884 May 92

The total incidence of childhood cancer varies rather little between different regions of the world, with cumulative risk to age 15 nearly always in the range 1.0-2.5 per thousand. Acute lymphoblastic leukaemia, especially in early childhood, is most common in populations of high socio-economic status and is the most frequent childhood cancer in all industrialised countries. The risk of Burkitt's lymphoma is highest in tropical Africa and Papua New Guinea; it is strongly associated with Epstein-Barr virus infection and intense immune stimulation by malaria. Other lymphomas are also relatively common in developing countries. Non-heritable retinoblastoma has a higher incidence among less affluent populations, suggesting an association with poor living conditions and maybe an infectious aetiology. In contrast, the incidence of Wilms' tumour and Ewing's sarcoma varies largely on ethnic lines, indicating a strong role for genetic predisposition. Much of the variation in recorded incidence of brain tumours and neuroblastoma may be due to varying levels of case ascertainment. Recently the incidence of childhood Kaposi's sarcoma has risen substantially in parts of Africa severely affected by the AIDS epidemic.
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PMID:Geographic and ethnic variations in the incidence of childhood cancer. 903 26

Acute Plasmodium falciparum malaria in African children allows expansion of latent Epstein-Barr virus infection, leading to colonization of lymph nodes by virus-infected lymphoblasts in 60% of cases as demonstrated by in situ hybridization for the detection of EBER-1 and EBER-2 RNA. This probably arises against a background of malaria-induced immunosuppression to EBV and concurrent lymphoid activation. The relevance of the results to the pathogenesis of African endemic Burkitt's lymphoma is discussed.
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PMID:Detection of EBV RNA (EBER-1 and EBER-2) in malaria lymph nodes by in situ hybridization. 944 32


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