Genetic architecture of knee radiographic joint space in healthy young adults

Evidence of a significant genetic component to the age-related degenerative joint disease osteoarthritis has been established, but the nature of genetic influences on normal joint morphology in healthy individuals remains unclear. Following up on our previous findings on the influence of body habitus on phenotypic variation in knee joint space [Duren et al., Human Biology 78:353-364 (2006)], the objective of the current study was to estimate the heritability of radiographic joint space in the knees of healthy young adults from a community-based sample of families. A sample of 253 subjects (mean age = 18.02 years) from 87 randomly ascertained nuclear and extended families was examined. Joint width (JW) and minimum joint space in the medial (MJS) and lateral (LJS) knee compartments were measured. A maximum-likelihood variance components method was used to estimate the heritability of MJS, LJS, and JW. Covariate effects of age, sex, age-by-sex interactions, stature, weight, and BMI were simultaneously estimated. Genetic correlation analyses were then conducted to examine relationships between trait pairs. MJS, LJS, and JW were each significantly heritable (p < 0.001), with heritabilities of 0.52, 0.53, and 0.63, respectively. The genetic correlation between MJS and LJS was not significantly different from 1. Genetic correlations between each joint space measure and JW were not significantly different from 0. This study demonstrates a significant genetic component to radiographic knee joint space during young adulthood in healthy subjects. This suggests that there are specific but as yet unidentified genes that influence the morphology of healthy articular cartilage, the target tissue of osteoarthritis. Genetic correlation analyses indicate complete pleiotropy between MJS and LJS but genetic independence of joint space and JW.     

Moderation of ruminal fermentation by ciliated protozoa in cattle fed a high-grain diet.

The objective of this study was to assess the influence of ciliated protozoa on ruminal fermentation in cattle fed high-grain diets. Six ruminally cannulated steers fed a corn-based grain diet (85% concentrate plus 15% alfalfa hay) at 12-h intervals were assigned randomly to two groups, ciliate free and faunated, in a crossover design. Defaunation was by ruminal emptying, omasal flushing, and treatment with sodium sulfosuccinate. Two to 3 weeks after defaunation, the ruminal contents of all steers were sampled before the morning feeding (0 h) and at 1, 2, 4, 6, 8, and 12 h after feeding to measure pH, analyze fermentation products, and monitor counts of ciliated protozoa and lactic acid-producing and -fermenting bacterial groups. Total numbers of ciliated protozoa in the faunated steers averaged 4.3 x 10(5)/g, and the protozoa consisted of nine genera. Ciliate-free steers had lower (P less than 0.01) ruminal pHs (pH 5.97) than faunated cattle (pH 6.45); however, the treatment-time interaction was not significant. Ruminal lactate and ammonia concentrations were similar in both groups. The total volatile fatty acid concentration was higher (P less than 0.05) in the ciliate-free steers than in the faunated steers and exhibited a treatment-time interaction (P less than 0.05). The acetate-to-propionate ratio was higher (P less than 0.05) in the faunated group than in the ciliate-free group and showed a treatment-time interaction (P less than 0.05). Total anaerobic bacterial counts were about fourfold higher in the ciliate-free group than in the faunated group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heritability of brachydactyly type A3 in children, adolescents, and young adults from an endogamous population in eastern Nepal

Brachymesophalangia-V (BMP-V), a short and broad middle phalanx of the fifth digit, is the most common of all skeletal anomalies of the hand. When this feature appears alone, it is clinically known as brachydactyly type A3 (BDA3). A high prevalence of BDA3 has been observed among the children of the Jirel ethnic group in eastern Nepal. As part of the Jiri Growth Study, a hand-wrist radiograph is taken annually of each child to assess skeletal development. For this study the most recent radiographs of 1,357 Jirel children, adolescents, and young adults (676 boys, 681 girls), age 3-20 years, were examined for the presence or absence of BDA3, to report the prevalence and estimate the heritability of BDA3 in the Jirel population. The overall prevalence of BDA3 in this sample was 10.5% (12.9% of the males and 8.9% of the females were classified as BDA3 affected). The additive genetic heritability of BDA3 was statistically significant in this sample (h2 +/- SE = 0.87 +/- 0.16, p < 0.0001). This study is the first to estimate the prevalence and heritability of BDA3 in a large South Asian family-based sample.     

Generational change in skin color variation among Habbani Yemeni Jews

The Habbani Yemeni Jews were a religious isolate in Yemen for centuries. Since a bottleneck in the late eighteenth century the population, composed of six partrilineages, has steadily grown. Isonymy analysis of Habbani genealogies reveals a significant increase in lineage endogamy by the early twentieth century, suggesting that microdifferentiation of Habbani population genetic structure along the patrilineages was occurring. We examine reflectance data from a "parental" generation of 159 individuals studied by Hulse in the 1960s and reflectance data from an "offspring" generation of 243 individuals studied by Towne in the 1980s. A greater amount of interlineage skin color differences is found in the offspring generation than in the parental generation. This finding is consistent with what is known of the evolution of Habbani population genetic structure.     

Toolbox for non-intrusive structural and functional analysis of recombinant VLP based vaccines: a case study with hepatitis B vaccine

Background

Fundamental to vaccine development, manufacturing consistency, and product stability is an understanding of the vaccine structure-activity relationship. With the virus-like particle (VLP) approach for recombinant vaccines gaining popularity, there is growing demand for tools that define their key characteristics. We assessed a suite of non-intrusive VLP epitope structure and function characterization tools by application to the Hepatitis B surface antigen (rHBsAg) VLP-based vaccine.

Methodology

The epitope-specific immune reactivity of rHBsAg epitopes to a given monoclonal antibody was monitored by surface plasmon resonance (SPR) and quantitatively analyzed on rHBsAg VLPs in-solution or bound to adjuvant with a competitive enzyme-linked immunosorbent assay (ELISA). The structure of recombinant rHBsAg particles was examined by cryo transmission electron microscopy (cryoTEM) and in-solution atomic force microscopy (AFM).

Principal Findings

SPR and competitive ELISA determined relative antigenicity in solution, in real time, with rapid turn-around, and without the need of dissolving the particulate aluminum based adjuvant. These methods demonstrated the nature of the clinically relevant epitopes of HBsAg as being responsive to heat and/or redox treatment. In-solution AFM and cryoTEM determined vaccine particle size distribution, shape, and morphology. Redox-treated rHBsAg enabled 3D reconstruction from CryoTEM images – confirming the previously proposed octahedral structure and the established lipid-to-protein ratio of HBsAg particles. Results from these non-intrusive biophysical and immunochemical analyses coalesced into a comprehensive understanding of rHBsAg vaccine epitope structure and function that was important for assuring the desired epitope formation, determinants for vaccine potency, and particle stability during vaccine design, development, and manufacturing.

Significance

Together, the methods presented here comprise a novel suite of non-intrusive VLP structural and functional characterization tools for recombinant vaccines. Key VLP structural features were defined and epitope-specific antigenicity was quantified while preserving epitope integrity and particle morphology. These tools should facilitate the development of other VLP-based vaccines.     

Application of a high-content multiparameter cytotoxicity assay to prioritize compounds based on toxicity potential in humans

Prioritization of compounds based on human hepatotoxicity potential is currently a key unmet need in drug discovery, as it can become a major problem for several lead compounds in later stages of the drug discovery pipeline. The authors report the validation and implementation of a high-content multiparametric cytotoxicity assay based on simultaneous measurement of 8 key cell health indicators associated with nuclear morphology, plasma membrane integrity, mitochondrial function, and cell proliferation. Compounds are prioritized by (a) computing an in vitro safety margin using the minimum cytotoxic concentration (IC(20)) across all 8 indicators and cell-based efficacy data and (b) using the minimal cytotoxic concentration alone to take into account concentration of drug in tissues. Feasibility data using selected compounds, including quinolone antibiotics, thiazolidinediones, and statins, suggest the viability of this approach. To increase overall throughput of compound prioritization, the authors have identified the higher throughput, plate reader-based CyQUANT assay that is similar to the high-content screening (HCS) assay in sensitivity of measuring inhibition of cell proliferation. It is expected that the phenotypic output from the multiparametric HCS assay in combination with other highly sensitive approaches, such as microarray-based expression analysis of toxic signatures, will contribute to a better understanding and predictivity of human hepatotoxicity potential.