Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Various peptide segments have been modeled as asymmetric amphipathic alpha-helices. Theoretical calculations have shown that they insert obliquely into model membranes. They have been named "tilted peptides". Molecular modeling results reported here also evidence the presence of tilted peptides in ADM-1 protein of Caenorhabditis elegans that may be involved in fusion events, in meltrin alpha, a protein implicated in myoblast fusion, in hemagglutinin of influenza virus, in the E2 glycoprotein of rubella virus, in the S protein of hepatitis B virus, in a subdomain of Ebola virus and in the malaria CS protein. Experimental results have indicated that tilted peptide fragments may be involved in cellular life events like sperm-egg fecondation, muscle development, protein translocation through signal sequences and cellular death caused by viral infection or parasite infestation. We speculate that membrane destabilization by these tilted peptides may be an important common step in life processes involving fusion phenomena.
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PMID:Are the fusion processes involved in birth, life and death of the cell depending on tilted insertion of peptides into membranes? 1033 92

In the present study, the genetic mechanisms responsible for generation of antibodies recognizing the dominant epitope within a synthetic peptide PS1CT3 were examined. PS1CT3 is a peptide model antigen containing residues 28-42 of the large protein of the surface antigen of hepatitis B virus as B epitope (designated PS1), and the known T-helper-cell epitope derived from the circumsporozoite protein of the malaria parasite Plasmodium falciparum (designated CT3). To characterize the repertoire generated, the immunoglobulin heavy chain variable regions from IgM and IgG monoclonal antibodies against PS1CT3 were sequenced. Although all IgG monoclonal antibodies were directed against the immunodominant epitope, the genetic elements used were diverse. Comparison of the sequence of germ line precursor IgM to a mature IgG revealed that during maturation of the primary IgM response only the heavy chain fragment of the antibody molecule underwent somatic mutation.
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PMID:B-cell responses to a peptide epitope: mutations in heavy chain alone lead to maturation of antibody responses. 1044 8

Plasmodium vivax is responsible for an approximate 35 million yearly human cases of malaria. Unfortunately, due to the low mortality rate associated with it and the difficulties of continuously in vitro culturing of this parasite, vaccine development against this human malaria has been largely neglected. In here, the antigenic properties of the merozoite surface protein 1 gene of P. vivax (PvMSP-1), were studied. Thus, seven recombinant bacterial plasmids coding different regions of the PvMSP-1 protein were constructed and used to immunize BALB/c mice. The results demonstrated that a plasmid encoding the entire N-terminus comprising 682 amino acids and a plasmid encoding the C-terminus including the two juxtaposed epidermal growth factor (EGF)-like domains fused to the Hepatitis B surface antigen, were antigenic. Moreover, the elicited immune responses were similar to those reported for these same PvMSP-1 regions in natural human infections.
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PMID:Antigenic properties of the merozoite surface protein 1 gene of Plasmodium vivax. 1046 30

The liver- and blood-stage-expressed serine repeat antigen (SERA) of Plasmodium falciparum is a candidate protein for a human malaria vaccine. We compared the immune responses induced in mice immunized with SERA-expressing plasmid DNA vaccines delivered by intramuscular (i.m.) injection or delivered intradermally by Gene Gun immunization. Mice were immunized with a pcdna3 plasmid encoding the entire 47-kDa domain of SERA (amino acids 17 to 382) or the N-terminal domain (amino acids 17 to 110) of SERA. Minimal antibody responses were detected following DNA vaccination with the N-terminal domain of SERA, suggesting that the N-terminal domain alone is not highly immunogenic by this route of vaccine delivery. Immunization of mice by Gene Gun delivery of the 47-kDa domain of SERA elicited a significantly higher serum antibody titer to the antigen than immunization of mice by i.m. injection with the same plasmid did. The predominant isotype subclass of the antibodies elicited to the SERA protein following i.m. and Gene Gun immunizations with SERA plasmid DNA was immunoglobulin G1. Coimmunization of mice with SERA plasmid DNA and a plasmid expressing the hepatitis B surface antigen (pCMV-s) by the i.m. route resulted in higher anti-SERA titers than those generated in mice immunized with the SERA DNA plasmid alone. Vaccination with DNA may provide a viable alternative or may be used in conjunction with protein-based subunit vaccines to maximize the efficacy of a human malaria vaccine that includes immunogenic regions of the SERA protein.
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PMID:Immune responses induced by gene gun or intramuscular injection of DNA vaccines that express immunogenic regions of the serine repeat antigen from Plasmodium falciparum. 1049 91

The safety and immunogenicity of 2 yeast-derived, blood-stage malaria vaccines were evaluated in a phase l trial. Healthy adults were given 2 or 3 doses of alum-adsorbed vaccine containing the 19 kDa carboxy-terminal fragment of the merozoite surface protein-1 (MSP-1(19)) derived from the 3D7 or the FVO strain of Plasmodium falciparum fused to tetanus toxoid T-helper epitopes P30 and P2. The first 2 doses of MSP-1(19) were well tolerated. Hypersensitivity reactions occurred in 3 subjects after the third dose of MSP-1(19), including bilateral injection site reactions in 2 (one with generalized skin rash), and probable histamine-associated hypotension in 1. Serum antibody responses to MSP-1(19) occurred in 5/16, 9/16 and 0/8 subjects given 20 microg of MSP-1(19), 200 microg of MSP-1(19), and control vaccines (hepatitis B or Td), respectively. Both MSP-1(19) vaccines were immunogenic in humans, but changes in formulation will be necessary to improve safety and immunogenicity profiles.
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PMID:Phase I trial of two recombinant vaccines containing the 19kd carboxy terminal fragment of Plasmodium falciparum merozoite surface protein 1 (msp-1(19)) and T helper epitopes of tetanus toxoid. 1051 44

The objective of this study was to epidemiologically describe potential infectious agents among rural people in the Republic of Yemen. This would aid clinicians in designing empirical therapy and public health officials in planning disease prevention. We sought to examine evidence for the geographical distribution of pathogens causing human hepatic and splenic disease among villagers and domestic animals living in three remote areas with differing altitudes. In June 1992, a cross-sectional survey was conducted at three survey sites of differing altitudes: 3080, 1440 and 250 m above sea level. Questionnaires, parasitic and serological tests were administered to 627 human volunteers. Additionally 317 domestic animals were studied. Malaria, schistosomiasis, and hepatitis B and C infections were found to be likely causes of human hepatic or splenic disease. Additionally, evidence of human and animal infections with the agents of brucellosis and Q fever was found: IgG antibodies against hepatitis E virus were discovered in two (2.0%) of the 100 volunteers. The prevalence of markers for human and animal disease was often lowest at the village of highest elevation, suggesting that increasing altitude, as a surrogate or a true independent risk factor, was protective against infection with the agents studied.
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PMID:Remote village survey for agents causing hepatosplenic disease in the Republic of Yemen. 1057 34

Unsafe injections and the consequent transmission of bloodborne pathogens are suspected to occur routinely in the developing world. This paper presents a review of the literature to determine the prevalence of unsafe injection practices and assess the disease burden of bloodborne infections. Quantitative data on injection usage and unsafe injection practices, such as the reuse of unsterilized syringe or needles between patients, is obtained by reviewing published articles and unpublished reports of the WHO. In addition, the transmissibility of hepatitis B and C viruses and HIV was determined using information from studies of needle-stick injuries. All epidemiological researches that associate injections with bloodborne diseases were examined to assess the attributable burden of bloodborne infections. It was estimated that each person in developing countries receives an average of 1.5 injections per annum. However, institutionalized children, children and adults who are sick or confined in hospitals, often receive 10-100 times as many injections. Of these injections, 95% are therapeutic, a majority of which are unnecessary. At least 50% of injections in 14 of 19 countries were unsafe. Furthermore, 18 studies present convincing evidence on the association of unsafe injection practices and the transmission of bloodborne viruses such as hepatitis B and C, Ebola, Lassa virus infections and malaria. Such practices account for a significant number of hepatitis B and C infections.
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PMID:Unsafe injections in the developing world and transmission of bloodborne pathogens: a review. 1059 26

Naturally occurring malaria, arbovirus infection and hepatitis in monkeys can be a hazard for the investigator and might interfere with the outcome of experiments. 63 young adult Macaca fascicularis from Malaysia were screened for these infections. About 1 year after their arrival in France, parasitaemia due to Plasmodium spp., was present in 6.4% of the animals and specific antibodies in 55.5%. 19 of 35 initially positive monkeys were tested again 2 years later. Parasitaemia was found in 1 of 4 monkeys and antibodies in 11 of 19 monkeys which were initially positive. 9 of the monkeys initially tested had low titres of antibodies to the Flavivirus genus. All animals were negative for the hepatitis B surface antigen and anti-HBc. The prevalence of IgG antibodies against hepatitis A was 46.0%. The implications in terms of control are discussed.
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PMID:Malaria, arbovirus and hepatitis infections in Macaca fascicularis from Malaysia. 1062 90

RTS,S is a novel pre-erythrocytic malaria vaccine based on the circumsporozoite surface protein (CSP) of Plasmodium falciparum linked to hepatitis B surface antigen (HBs) and combined with a novel adjuvant system (SBAS2). We have conducted a Phase I trial with three doses of this vaccine given at 0, 1, and 6 months to 20 semi-immune, adult, male volunteers in The Gambia to assess its safety and immunogenicity. Eighteen of the 20 volunteers completed the study. There were no clinically significant local or systemic adverse events following each vaccination. Hematologic and biochemical indices before and two weeks after each vaccination showed no evidence of toxicity. Antibody titers to both CSP and HBs showed a significant increase after vaccination; these were the largest after the third dose. We conclude that the RTS,S/SBAS2 vaccine induces no significant toxicity in this semi-immune population and produces significant increases in antibody titers to CSP.
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PMID:A phase I safety and immunogenicity trial with the candidate malaria vaccine RTS,S/SBAS2 in semi-immune adults in The Gambia. 1067 60

Oman is generally hot and dry, but the Salalah region in southern Dhofar province is relatively cool and rainy during the summer monsoon, and has a distinctive pattern of infection. Important, notifiable infections in Oman include tuberculosis, brucellosis (endemic in Dhofar), acute gastroenteritis, and viral hepatitis: 4.9% of the adults are seropositive for hepatitis B surface antigen and approximately 1.2% for hepatitis C virus. Infection with human immunodeficiency virus is uncommon, and leprosy, rabies, and Crimean-Congo hemorrhagic fever are rare. Between 1990 and 1998, the incidence of malaria, (>70% due to Plasmodium falciparum) decreased from 32,700 to 882 cases. Cutaneous and visceral leishmaniasis (caused by Leishmania tropica and L. infantum, respectively) and Bancroftian filariasis occur sporadically. Intestinal parasitism ranges from 17% to 42% in different populations. A solitary focus of schistosomiasis mansoni in Dhofar has been eradicated. There are major programs for the elimination of tuberculosis, leprosy, and malaria, and to control brucellosis, leishmaniasis, sexually transmitted diseases, trachoma, acute respiratory infection in children, and diarrheal diseases. The Expanded Program on Immunization was introduced in 1981: diphtheria, neonatal tetanus, and probably poliomyelitis have been eliminated.
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PMID:Infectious and tropical diseases in Oman: a review. 1067 71


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