Time-resolved fluorescence resonance energy transfer and surface plasmon resonance-based assays for retinoid and transthyretin binding to retinol-binding protein 4

Retinol-binding protein-4 (RBP4) is an emerging candidate drug target for type 2 diabetes and lipofuscin-mediated macular degeneration. The retinoic acid derivative fenretinide (N-(4-hydroxyphenyl) retinamide; HPR) exerts therapeutic effects in mouse models of obesity, diabetes, and Stargardt’s disease by targeting RBP4. Fenretinide competes with retinoids for RBP4 binding, disrupts RBP4-transthyretin (TTR) complexes, and results in urinary secretion of RBP4 and systemic depletion of retinol. To enable the search for nonretinoid molecules with fenretinide-like activities we developed a HTS-compatible homogeneous TR-FRET assay monitoring the displacement of retinoic acid derivatives from RBP4 in high-density 384-well and 1536-well microtiter plate formats. The retinoid displacement assay proved to be highly sensitive and robust after miniaturization with IC₅₀s for fenretinide and retinol ranging around 50 and 100 nM, respectively, and Z′-factors around 0.7. In addition, a surface plasmon resonance (SPR)-based secondary assay was developed to interrogate small molecule RBP4 binders for their ability to modulate the RBP4-TTR interaction. Finally, a 1.6 × 10⁶ compound library was screened against the retinoid displacement assay. Several potent retinoid competitors were identified that also appeared to disrupt RBP4-TTR complexes. Some of these compounds could potentially serve as valuable tools to further probe RBP4 biology in the future.     

Reliability and stability of mothers' reports about their pregnancies with twins.

The objective of this study was to determine if mothers' retrospective reports about events in their pregnancies with twins are reliable and stable. Six hundred and twenty-four mothers completed psychiatric interviews about their twins. These interviews also contained questions about the mothers' pregnancies, the perinatal period, and the child's early development. The mothers reported first on one twin and then on the other with interviews spaced from 3 days to 2 weeks apart. Thus mothers reported on the same pregnancy twice. Of these mothers, 47 were re-interviewed 6 to 18 months later by raters blind to the results of the initial interview. The twin design allowed us to compare the short-term reliability of the 624 mothers' reports of the same pregnancy. The re-interview of the 47 mothers enabled us to compare the stability of reports over a longer time period. Agreement between the reports was measured with the kappa statistic. Kappas were good to excellent for the short-term reports of pregnancy for each twin for the 624 mothers. Kappas were equally high for the 47 mothers that were re-interviewed 6 to 18 months later. Mothers show good reliability and stability of reporting about events during pregnancy.     

Sequential morphologic changes in adult Echinococcus granulosus during complement-mediated lysis In vitro

Herd R. P., Ko L., Weisbrode S. E. and Heath D. D. 1984. Sequential morphologic changes in adult Echinococcus granulosus during complement-mediated lysis in vitro. International Journal for Parasltology14:141–149. Sequential changes (5,10, 20, 30,40, 50 min, 1, 2, 3, 4, 5, 6, 7, 8, h) were observed by light, scanning and transmission electron microscopy after 38-day-old adult Echinococcus granulosus were exposed to 50% guinea pig serum in vitro. Early changes within 3 h included contraction of worms, fusion of microtriehes, vacuolization and vesiculization of the distal cytoplasm, followed by rupture of vesicles leading to erosion and loss of the distal cytoplasm. This was most marked in the terminal proglottid but ultimately there was complete erosion of the distal cytoplasm of all proglottids and the scolex. After 3 h there was loss of definition of organelles, apparent edema of the perinuclear cytoplasm and, in some instances, rupture of the circular muscle layer with extrusion of parenchyma. Adult tape-worms exposed to heat-inactivated complement showed none of these changes. Lysis and death of the parasite was attributed to osmotic changes subsequent to the formation of trans-membrane channels induced by complement-mediated attack of the tegument after activation of the alternate pathway by factors present in the cestode tegument.     

Simultaneous hermaphroditism; cost and benefit

Current theories explain simultaneous hermaphroditism by the advantage it gives to organisms which are widely dispersed or sluggish, resulting in a low frequency of reproductive contacts. It is difficult to see why hermaphroditism is not more widespread unless there is some counterbalancing disadvantage.It is suggested that hermaphrodites suffer an energetic cost because they maintain two reproductive systems and a cost due to the reduced number or viability of offspring which may result from accidental self-fertilization. These costs will result in a disadvantage to hermaphroditism (compared to gonochorism) when reproductive contacts are frequent. However, even in widely dispersed or sluggish organisms behavioural mechanisms may exist which increase the frequency of reproductive contacts, favouring gonochorism instead of hermaphroditism.It is argued that externally fertilizing species should as a rule be gonochoric and that species which brood their young may often be hermaphroditic. Hermaphroditism in species which form permanent male/female pairs in the breeding season could result in more zygotes being produced. However, where parental care of the young is important, it is suggested that gonochorism and sexual dimorphism may result in more progeny being reared.     

The human aldose reductase gene maps to chromosome region 7q35

Summary The human aldose reductase (AR) gene has been mapped to chromosome 7 using the polymerase chain reaction to specifically amplify the human AR sequence in hamster/human hybrid DNA and also in mouse/ human monochromosome hybrids. The assignment to chromosome 7 was confirmed by in situ hybridisation to human metaphase chromosomes using a novel, rapid hybridisation, method giving a regional localisation at 7q35.     

Interactions between rate processes with different timescales explain counterintuitive foraging patterns of arctic wintering eiders

To maximize fitness, animals must respond to a variety of processes that operate at different rates or timescales. Appropriate decisions could therefore involve complex interactions among these processes. For example, eiders wintering in the arctic sea ice must consider locomotion and physiology of diving for benthic invertebrates, digestive processing rate and a nonlinear decrease in profitability of diving as currents increase over the tidal cycle. Using a multi-scale dynamic modelling approach and continuous field observations of individuals, we demonstrate that the strategy that maximizes long-term energy gain involves resting during the most profitable foraging period (slack currents). These counterintuitive foraging patterns are an adaptive trade-off between multiple overlapping rate processes and cannot be explained by classical rate-maximizing optimization theory, which only considers a single timescale and predicts a constant rate of foraging. By reducing foraging and instead digesting during slack currents, eiders structure their activity in order to maximize long-term energetic gain over an entire tide cycle. This study reveals how counterintuitive patterns and a complex functional response can result from a simple trade-off among several overlapping rate processes, emphasizing the necessity of a multi-scale approach for understanding adaptive routines in the wild and evaluating mechanisms in ecological time series.     

A factor synthesized by rabbit periosteal fibroblasts stimulates bone resorption and collagenase production by connective tissue cells in vitro

Unstimulated monolayer cultures of confluent rabbit periosteal fibroblasts synthesize a factor that stimulates bone resorption in vitro. Furthermore it stimulates rabbit chondrocytes and mouse osteoblasts to synthesize collagenase. The factor has no effect on dead bone in culture, and its activity on live bone is mediated principally by osteoclasts, since it is 75% inhibited by salmon calcitonin. Characterization of the factor by gel filtration and isoelectric focusing indicates an M_r in the range 15 000–25 000 and a pI corresponding to approx. pH 4.7. These biological and physicochemical properties are similar to those reported for a factor released by peripheral blood monocytes. However, whereas human monocyte factor in both the crude and partially-purified state exhibits interleukin-1 activity, crude and fractionated periosteal fibroblast-conditioned medium does not. This is the first report of a conditioned medium containing a molecule like the monocyte-factor which appears to have no interleukin 1 activity. The factor may be synthesized by a wide range of cell types, and could have an important role in mediating connective tissue degradation during both physiological and pathological resorption.     

Unraveling the Genetic Etiology of Adult Antisocial Behavior: A Genome-Wide Association Study

Crime poses a major burden for society. The heterogeneous nature of criminal behavior makes it difficult to unravel its causes. Relatively little research has been conducted on the genetic influences of criminal behavior. The few twin and adoption studies that have been undertaken suggest that about half of the variance in antisocial behavior can be explained by genetic factors. In order to identify the specific common genetic variants underlying this behavior, we conduct the first genome-wide association study (GWAS) on adult antisocial behavior. Our sample comprised a community sample of 4816 individuals who had completed a self-report questionnaire. No genetic polymorphisms reached genome-wide significance for association with adult antisocial behavior. In addition, none of the traditional candidate genes can be confirmed in our study. While not genome-wide significant, the gene with the strongest association (p-value = 8.7×10⁻⁵) was DYRK1A, a gene previously related to abnormal brain development and mental retardation. Future studies should use larger, more homogeneous samples to disentangle the etiology of antisocial behavior. Biosocial criminological research allows a more empirically grounded understanding of criminal behavior, which could ultimately inform and improve current treatment strategies.