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At least 127 records · Page 7Linked to original sources
PubMed2000

Comparative quantification of diverse serotypes of HIV-1 in plasma from a diverse population of patients.

HIV-1 is characterised by extensive genetic variability encompassing at least 10 different phylogenetically related clades within the major group of HIV-1 subtypes. Most commercially available HIV-1 RNA plasma viral load assays have been optimised with clade B viruses and may yield misleadingly low RNA levels for nonclade B viruses that are increasingly found in Europe. In this study we compare the most recent versions of the Roche Amplicor HIV Monitor and the Chiron Quantiplex for ability to detect viraemia in a population of patients infected with a range of HIV-1 subtypes. EDTA-treated plasma was obtained from 206 patients. The Amplicor and Quantiplex assays were carried out in accordance with manufacturers' instructions. Results from 53/206 (25.7%) samples differed by >0.4 log between Amplicor 1.5 and Quantiplex 3.0. A >0.5 log and 1.0 log difference was detected between Amplicor 1.5 and Quantiplex 3.0 in 37/206 (17.9%) and 7/206 (3.4%) of samples, respectively. Overall, Amplicor 1.5 gave a median value of 0.22 log higher than Quantiplex 3.0. Discordant results were detected in 53 out of 206 (25.7%) samples. Of these 22 out of 123 (17.9%) samples were of UK origin, 18 out of 43 (41.9%) African, 1 out of 8 (12.5%) South American, 1 out of 6 (16.7%) North American, 4 out of 9 (44.4%) North European, 3 out of 11 (23.7%) South European and 3 out of 7 (42.3%) Asian samples, respectively. Serotyping revealed that discordant viral load results between Amplicor 1.5 and Quantiplex 3.0 occurred within samples from all subtypes (A-E). Despite the improvements made to both the Roche Amplicor and the Chiron Quantiplex assays discordant results were detected between the two assays in 25.7% of cases. In a substantial minority of patients there were major discrepancies between the two assays that were not explained by HIV subtype differences.

HIV Infections↗
PubMed1994

Diversity within diversity: molecular approaches to studying microbial interactions with insects.

DNA sequence information has greatly augmented the number of characters available for analysis in phylogenetic research. Nowhere is this more evident than in studies of microbial evolution. Ribosomal DNA sequence data has simultaneously permitted the distinction between individual species and the inference of their phylogenetic relationships in many cases where both were formerly impossible. These have contributed to our understanding of the ecology of particular microbe-host interactions and the history of these relationships over evolutionary time. We describe examples from two ends of the ecological spectrum in insect/bacterial associations: one in which bacteria mediate host cytoplasmic incompatibility and parthenogenesis, and the other in which mycetocyte bacteria augment host nutrition. In the former, the pattern of bacterial interaction is general, with the same or closely related strains of the genus Wolbachia associating with a wide range of insect taxa. In the latter, concordance between host and microbe phylogenies suggests cospeciation between bacteria and host, although it is as yet unclear whether this process has involved step-wise, reciprocal coevolution. We conclude with a discussion of how developments in molecular techniques may aid in analyzing more complex interactions between insects and microbes.

Animals↗
PubMed2004

Cardiac connexins Cx43 and Cx45: formation of diverse gap junction channels with diverse electrical properties.

HeLa cells expressing rat connexin43 (Cx43) and/or mouse Cx45 were studied with the dual voltage-clamp technique. Different types of cell pairs were established and their gap junction properties determined, i.e. the dependence of the instantaneous and steady-state conductances (gj,inst, gj,ss) on the transjunctional voltage (Vj) and the kinetics of inactivation of the gap junction current (Ij). Pairs of singly transfected cells showed homogeneous behaviour at both Vj polarities. Homotypic Cx43-Cx43 and Cx45-Cx45 cell pairs yielded distinct symmetrical functions gj,inst=f(Vj) and gj,ss=f(Vj). Heterotypic Cx43-Cx45 preparations exhibited asymmetric functions gj,inst=f(Vj) and gj,ss=f(Vj) suggesting that connexons Cx43 and Cx45 gate with positive and negative Vj, respectively. Preparations containing a singly (Cx43 or Cx45) or doubly (Cx43/45) transfected cell showed quasi-homogeneous behaviour at one Vj polarity and heterogeneous behaviour at the other polarity. The former yielded Boltzmann parameters intermediate between those of Cx43-Cx43, Cx45-Cx45 and Cx43-Cx45 preparations; the latter could not be explained by homotypic and heterotypic combinations of homomeric connexons. Each pair of doubly transfected cells (Cx43/Cx45) yielded unique functions gj,inst=f(Vj) and gj,ss=f(Vj). This can not be explained by combinations of homomeric connexons. We conclude that Cx43 and Cx45 form homomeric-homotypic, homomeric-heterotypic channels as well as heteromeric-homotypic and heteromeric-heterotypic channels. This has implications for the impulse propagation in specific areas of the heart.

Animals↗
PubMed2005

Strategies and issues for managing menopause-related symptoms in diverse populations: ethnic and racial diversity.

Menopause is a naturally occurring "equal opportunity" event that every woman who lives beyond the age of approximately 52 years will experience. During the next 20 years, approximately 3.5 million African American women, 2 million Latinas, and 1 million Asian American women will enter the menopause. How a woman approaches the menopausal transition depends on a number of factors, from educational level to socioeconomic status; health-related factors, including stress; and marital status. Increasingly, the roles of race and ethnicity, as they relate to menopausal symptoms, are being explored. Understanding similarities and differences among women of color in perceptions, attitudes, and expectations surrounding the menopause can help provide culturally appropriate care and promote lifestyles that may decrease symptoms and increase quality of life. For example, minority women are usually the gatekeepers for healthcare for themselves and their families and have a highly developed social support network, often including extended family, a church community, and involvement in sororal or social organizations. In the future, research on menopausal symptoms among women of different racial/ethnic groups should focus on exploring in greater detail the effect of dietary factors and body mass index, additional evaluation of pituitary sensitivity, and use of complementary and alternative medicines in symptom management, with a better understanding of the risks and benefits of such therapies.

Complementary Therapies↗
PubMed1998

Complement diversity: a mechanism for generating immune diversity?

Unlike mammalian species, several cold-blooded species have been shown to possess multiple forms of complement components. The multiple forms of C3 characterized in several fish species can bind with different specificities to various complement-activating surfaces. Here, Oriol Sunyer, Ioannis Zarkadis and John Lambris explore the possible advantages conferred by having multiple forms of individual complement proteins in a single organism.

Animals↗
PubMedDate not supplied

A general treatment of solubility. 3. Principal component analysis (PCA) of the solubilities of diverse solutes in diverse solvents.

A phenomenological study of solubility has been conducted using a combination of quantitative structure-property relationship (QSPR) and principal component analysis (PCA). A solubility database of 4540 experimental data points was used that utilized available experimental data into a matrix of 154 solvents times 397 solutes. Methodology in which QSPR and PCA are combined was developed to predict the missing values and to fill the data matrix. PCA on the resulting filled matrix, where solutes are observations and solvents are variables, shows 92.55% of coverage with three principal components. The corresponding transposed matrix, in which solvents are observations and solutes are variables, showed 62.96% of coverage with four principal components.

Journal Article↗
PubMed2004

Two-dimensional diversity: screening human cDNA phage display libraries with a random diversity probe for the display cloning of phosphotyrosine binding domains.

A random phosphopeptide probe (bio-pYZZZ) has been used for the isolation and identification of multiple SH2 domains from human cDNA-displaying phage libraries. In addition, on-phage analysis and quantification of binding affinities for these phage-displayed proteins has shown them to be functional domains, retaining the same characteristics as in their native state.

Cloning, Molecular↗
PubMed1986

Antigenic diversity and size diversity of Plasmodium falciparum antigens in isolates from Gambian patients. I. S-antigens.

Ring-stage asexual parasites of P. falciparum were collected from six Gambian children and the S-antigens radiolabelled by 3H-glycine uptake during in vitro culture up to rupture of infected cells and merozoite release. Ouchterlony double diffusion of boiled culture supernatants against a panel of adult Gambian sera identified one S-antigen precipitin arc for five isolates and two precipitin arcs for one isolate. Five of the six isolates were serologically distinct. Analysis of S-antigens by comparison of SDS-polyacrylamide gel electrophoresis patterns of heat-treated soluble proteins revealed a more complex pattern of 3H-labelled S-antigens that was different for each isolate. There were between two and six different 3H-labelled bands for each isolate in the size range of molecular weight 137 000 to 285 000. This result confirms the large size range of S-antigens identified with culture adapted P. falciparum. Several bands were relatively weakly labelled with 3H-glycine, suggesting that natural isolates contain one or two predominant S-antigen phenotypes and several other S-antigen phenotypes expressed by minor parasite subpopulations. Immunoprecipitation was performed using a panel of sera from Gambian adults, or, acute and 3 week convalescent sera from the same patients used for S-antigen radiolabelling. Adult sera generally immunoprecipitated some of the S-antigens in each isolate, including antigens that must represent extremely minor parasite subpopulations since they could not be seen in the patterns of non-immunoprecipitated heat-stable proteins. Sera from convalescent children were generally negative on immunoprecipitation, even with the homologous isolate. In one case we observed the acquisition of specific immunoprecipitating antibody to one of the homologous S-antigens during the convalescent period. The antigenic and structural complexity of S-antigens in natural isolates that have not been submitted to the selection pressure of adaptation for in vitro culture is clearly greater than for culture adapted P. falciparum.

Adult↗