228 research outputs found
Age-related differences in the neck strength of adolescent rugby players:A cross-sectional cohort study of Scottish schoolchildren
No full textTo evaluate the neck strength of school-aged rugby players, and to define the relationship with proxy physical measures with a view to predicting neck strength
Limited antigenic diversity of Plasmodium falciparumapical membrane antigen 1 supports the development of effective multi-allele vaccines
No full textBackground: Polymorphism in antigens is a common mechanism for immune evasion used by many important pathogens, and presents major challenges in vaccine development. In malaria, many key immune targets and vaccine candidates show substantial polymorphism. However, knowledge on antigenic diversity of key antigens, the impact of polymorphism on potential vaccine escape, and how sequence polymorphism relates to antigenic differences is very limited, yet crucial for vaccine development. Plasmodium falciparum apical membrane antigen 1 (AMA1) is an important target of naturally-acquired antibodies in malaria immunity and a leading vaccine candidate. However, AMA1 has extensive allelic diversity with more than 60 polymorphic amino acid residues and more than 200 haplotypes in a single population. Therefore, AMA1 serves as an excellent model to assess antigenic diversity in malaria vaccine antigens and the feasibility of multi-allele vaccine approaches. While most previous research has focused on sequence diversity and antibody responses in laboratory animals, little has been done on the cross-reactivity of human antibodies. Methods: We aimed to determine the extent of antigenic diversity of AMA1, defined by reactivity with human antibodies, and to aid the identification of specific alleles for potential inclusion in a multi-allele vaccine. We developed an approach using a multiple-antigen-competition enzyme-linked immunosorbent assay (ELISA) to examine cross-reactivity of naturally-acquired antibodies in Papua New Guinea and Kenya, and related this to differences in AMA1 sequence. Results: We found that adults had greater cross-reactivity of antibodies than children, although the patterns of cross-reactivity to alleles were the same. Patterns of antibody cross-reactivity were very similar between populations (Papua New Guinea and Kenya), and over time. Further, our results show that antigenic diversity of AMA1 alleles is surprisingly restricted, despite extensive sequence polymorphism. Our findings suggest that a combination of three different alleles, if selected appropriately, may be sufficient to cover the majority of antigenic diversity in polymorphic AMA1 antigens. Antigenic properties were not strongly related to existing haplotype groupings based on sequence analysis. Conclusions: Antigenic diversity of AMA1 is limited and a vaccine including a small number of alleles might be sufficient for coverage against naturally-circulating strains, supporting a multi-allele approach for developing polymorphic antigens as malaria vaccines
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Analysis of gait kinematics to determine the effect of manipulating the appearance of stairs to improve safety: a linked series of laboratory-based, repeated measures studies
No full textBackground: Falls on stairs are a common and dangerous problem for older people. This series of studies evaluated whether or not selected changes to the appearance of stairs could make them safer for older people to negotiate. Objectives: To determine the effect of (1) a step edge highlighter and its position and (2) an optimised horizontal–vertical (H–V) visual illusion placed on a step riser on gait safety during stair descent and ascent. Design: A series of studies using a repeated measures, laboratory-based design, investigating gait control and safety in independently mobile older people. Setting: The University of Bradford Vision and Mobility Laboratory. Participants: Fit and healthy older people aged 60 years of age or more, independently mobile, reasonably active and with normal healthy eyes and corrected vision. Interventions: A step edge highlighter in a variety of offsets from the stair edge and an optimised H–V visual illusion placed on the stair riser. The H–V illusion was provided on a staircase by horizontal step edge highlighters on the tread edges and vertical stripes on the step risers. Main outcome measures: Gait parameters that are important for safe stepping in ascent and descent, measured using three-dimensional lower limb segmental kinematic data
Genetic Variability in Brazilian Populations of Biomphalaria straminea Complex Detected by Simple Sequence Repeat Anchored Polymerase Chain Reaction Amplification
No full textMem Inst Oswaldo Cruz 2001, Volume 96, Number 4, pp. 535-544 Genetic
Variability in Brazilian Populations of Biomphalaria straminea Complex
Detected by Simple Sequence Repeat Anchored Polymerase Chain Reaction
Amplification Roberta L Caldeira, Teofânia HDA Vidigal, Andrew JG
Simpson,Omar S Carvalho Code Number: oc01082 ABSTRACT: Biomphalaria
glabrata, B. tenagophila and B. straminea are intermediate hosts of
Schistosoma mansoni, in Brazil. The latter is of epidemiological
importance in the northwest of Brazil and, due to morphological
similarities, has been grouped with B. intermedia and B. kuhniana in a
complex named B. straminea. In the current work, we have standardized
the simple sequence repeat anchored polymerase chain reaction (SSR-PCR)
technique, using the primers (CA)8RY and K7, to study the genetic
variability of these species. The similarity level was calculated using
the Dice coefficient and genetic distance using the Nei and Li
coefficient. The trees were obtained by the UPGMA and neighbor-joining
methods. We have observed that the most related individuals belong to
the same species and locality and that individuals from different
localities, but of the same species, present clear heterogeneity. The
trees generated using both methods showed similar topologies. The
SSR-PCR technique was shown to be very efficient in intrapopulational
and intraspecific studies of the B. straminea complex snails.
KEYWORDS: snails, Planorbidae, Biomphalaria straminea, Biomphalaria
kuhniana, Biomphalaria intermedia, SSR anchored PCR amplification,
genetic variability Copyright 2001 Mem Inst Oswaldo Cru
Evidentiation of Paramyosin (Sm-97) as a modulating antigen on granulomatous hypersensitivity to Schistosoma mansoni eggs
No full textMem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 92(5), September/October
1997, pp. 663-667 Evidentiation of Paramyosin (Sm-97) as a modulating
antigen on granulomatous hypersensitivity to Schistosoma mansoni eggs
Cristine Hirsch, Claudia Carvalho-Queiroz, Gloria R Franco, Sergio DJ
Pena, Andrew JG Simpson, Alfredo M Goes Code Number:OC97125 Sizes of
Files: Text: 21.6K Graphics: photographs (jpg) - 100.9K A Schistosoma
mansoni adult worm anionic fraction (PIII) has previously been shown to
protect mice against challenge infection and to reduce pulmonary and
hepatic granulomatous hypersensitivity. Serum from PIII-immunized
rabbit was used to screen a lambda gt11 cDNA library from S. mansoni
adult worm in order to identify antigens capable of modulating
granulomatous hypersensitivity. We obtained four clones with 400
(Sm-III.11), 900 (Sm-III.16), 1100 (Sm-III.10) and 1300 (Sm-III.12) bp
of length. All clone-specific antibodies were able to recognize most of
the PIII components. The sequence analysis showed that these clones
presented high homology with S. mansoni paramyosin (Sm-97). These
findings ascribe a new function to this antigen with an important role
in modulation of granulomatous hypersensitivity to S. mansoni eggs. Key
words: Paramyosin - modulation - granuloma - Schistosoma mansoni
Copyright 1997 Fundacao Oswaldo Cru
Identification of Biomphalaria havanensis and Biomphalaria obstructa Populations from Cuba Using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism of the Ribosomal RNA Intergenic Spacer
No full textMem Inst Oswaldo Cruz 2001, Volume 96, Number 5, pp. 661-665
Identification of Biomphalaria havanensis and Biomphalaria obstructa
Populations from Cuba Using Polymerase Chain Reaction and Restriction
Fragment Length Polymorphism of the Ribosomal RNA Intergenic Spacer
Teofânia HDA Vidigal, Roberta L Caldeira, Andrew JG Simpson, Omar
S Carvalho Code Number: oc01102 ABSTRACT: In Cuba, several
Biomphalaria species have been reported such as B. orbignyi, B.
schrammi, B. helophila, B. havanensis and B. peregrina; only the latter
three are considered as potential hosts of Schistosoma mansoni. The
specific identification of Biomphalaria species is based on anatomical
and morphological characters of genital organs and shells. The correct
identification of these snails is complicated by the high variation in
these characters, similarity among species and in some cases by the
small size of the snails. In this paper, we reported the classical
morphological identification, the use of PCR and RFLP analysis of the
internal transcribed spacer region of the ribosomal RNA genes for
molecular identification of seven snail populations from different
localities in Cuba. Using morphological and molecular analysis, we
showed that among the studied Cuban Biomphalaria populations only B.
havanensis and B. obstructa species were found. KEYWORDS: Biomphalaria
havanensis, Biomphalaria obstructa, polymerase chain reaction, internal
transcribed spacer, ribosomal DNA, snails, Cuba Copyright 2001 Mem
Inst Oswaldo Cru
Identification of Biomphalaria havanensis and Biomphalaria obstructa Populations from Cuba Using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism of the Ribosomal RNA Intergenic Spacer
No full textMem Inst Oswaldo Cruz 2001, Volume 96, Number 5, pp. 661-665
Identification of Biomphalaria havanensis and Biomphalaria obstructa
Populations from Cuba Using Polymerase Chain Reaction and Restriction
Fragment Length Polymorphism of the Ribosomal RNA Intergenic Spacer
Teofânia HDA Vidigal, Roberta L Caldeira, Andrew JG Simpson, Omar
S Carvalho Code Number: oc01102 ABSTRACT: In Cuba, several
Biomphalaria species have been reported such as B. orbignyi, B.
schrammi, B. helophila, B. havanensis and B. peregrina; only the latter
three are considered as potential hosts of Schistosoma mansoni. The
specific identification of Biomphalaria species is based on anatomical
and morphological characters of genital organs and shells. The correct
identification of these snails is complicated by the high variation in
these characters, similarity among species and in some cases by the
small size of the snails. In this paper, we reported the classical
morphological identification, the use of PCR and RFLP analysis of the
internal transcribed spacer region of the ribosomal RNA genes for
molecular identification of seven snail populations from different
localities in Cuba. Using morphological and molecular analysis, we
showed that among the studied Cuban Biomphalaria populations only B.
havanensis and B. obstructa species were found. KEYWORDS: Biomphalaria
havanensis, Biomphalaria obstructa, polymerase chain reaction, internal
transcribed spacer, ribosomal DNA, snails, Cuba Copyright 2001 Mem
Inst Oswaldo Cru
Identification of Biomphalaria havanensis and Biomphalaria obstructa populations from Cuba using polymerase chain reaction and restriction fragment length polymorphism of the ribosomal RNA intergenic spacer
No full textIn Cuba, several Biomphalaria species have been reported such as B. orbignyi, B. schrammi, B. helophila, B. havanensis and B. peregrina; only the latter three are considered as potential hosts of Schistosoma mansoni. The specific identification of Biomphalaria species is based on anatomical and morphological characters of genital organs and shells. The correct identification of these snails is complicated by the high variation in these characters, similarity among species and in some cases by the small size of the snails. In this paper, we reported the classical morphological identification, the use of PCR and RFLP analysis of the internal transcribed spacer region of the ribosomal RNA genes for molecular identification of seven snail populations from different localities in Cuba. Using morphological and molecular analysis, we showed that among the studied Cuban Biomphalaria populations only B. havanensis and B. obstructa species were found
Genetic variability in Brazilian populations of Biomphalaria straminea complex detected by simple sequence repeat anchored polymerase chain reaction amplification
No full textBiomphalaria glabrata, B. tenagophila and B. straminea are intermediate hosts of Schistosoma mansoni, in Brazil. The latter is of epidemiological importance in the northwest of Brazil and, due to morphological similarities, has been grouped with B. intermedia and B. kuhniana in a complex named B. straminea. In the current work, we have standardized the simple sequence repeat anchored polymerase chain reaction (SSR-PCR) technique, using the primers (CA)8RY and K7, to study the genetic variability of these species. The similarity level was calculated using the Dice coefficient and genetic distance using the Nei and Li coefficient. The trees were obtained by the UPGMA and neighbor-joining methods. We have observed that the most related individuals belong to the same species and locality and that individuals from different localities, but of the same species, present clear heterogeneity. The trees generated using both methods showed similar topologies. The SSR-PCR technique was shown to be very efficient in intrapopulational and intraspecific studies of the B. straminea complex snails
Polymerase chain reaction and restriction fragment length polymorphism of cytocrome oxidase subunit I used for differentiation of Brazilian Biomphalaria species intermediate host of Schistosoma mansoni
No full textThe intermediate hosts of Schistosoma mansoni, in Brazil, Biomphalaria glabrata, B. tenagophila and B. straminea, were identified by restriction fragment length polymorphism analysis of the mitochondrial gene cytochrome oxidase I (COI). We performed digestions with two enzymes (AluI and RsaI), previously selected, based on sequences available in Genbank. The profiles obtained with RsaI showed to be the most informative once they were polymorphic patterns, corroborating with much morphological data. In addition, we performed COI digestion of B. straminea snails from Uruguay and Argentina
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