Association between ultrasound-detected synovitis and knee pain: a population-based case–control study with both cross-sectional and follow-up data

Background

An important role for synovial pathology in the initiation and progression of knee osteoarthritis has been emphasised recently. This study aimed to examine whether ultrasonography-detected synovial changes associate with knee pain (KP) in a community population.

Methods

A case–control study was conducted to compare people with early KP (n?=?298), established KP (n?=?100) or no KP (n?=?94) at baseline. Multinomial logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) between groups adjusted for radiographic osteoarthritis (ROA) severity and other confounding factors. After 1 year, 255 participants with early and established KP completed the follow-up questionnaire for changes in KP. Logistic regression with adjustment was used to determine predictors of KP worsening.

Results

At baseline, effusion was associated with early KP (OR 2.64, 95% CI 1.57–4.45) and established KP (OR 5.07, 95% CI 2.74–9.38). Synovial hypertrophy was also associated with early KP (OR 5.43, 95% CI 2.12–13.92) and established KP (OR 13.27, 95% CI 4.97–35.43). The association with effusion diminished when adjusted for ROA. Power Doppler signal was uncommon (early KP 3%, established KP 2%, controls 0%). Baseline effusion predicted worsening of KP at 1 year (OR 1.95, 95% CI 1.05–3.64). However, after adjusting for ROA, the prediction was insignificant (adjusted OR 0.95, 95% CI 0.44–2.02).

Conclusions

Ultrasound effusion and synovial hypertrophy are associated with KP, but only effusion predicts KP worsening. However, the association/prediction is not independent from ROA. Power Doppler signal is uncommon in people with KP. Further study is needed to understand whether synovitis is directly involved in different types of KP.

     

Biofabrication of antibodies and antigens via IgG‐binding domain engineered with activatable pentatyrosine pro‐tag

We report the assembly of seven different antibodies (and two antigens) into functional supramolecular structures that are specifically designed to facilitate integration into devices using entirely biologically based bottom‐up fabrication. This is enabled by the creation of an engineered IgG‐binding domain (HG3T) with an N‐terminal hexahistidine tag that facilitates purification and a C‐terminal enzyme‐activatable pentatyrosine “pro‐tag” that facilitates covalent coupling to the pH stimuli‐responsive polysaccharide, chitosan. Because we confer pH‐stimuli responsiveness to the IgG‐binding domain, it can be electrodeposited or otherwise assembled into many configurations. Importantly, we demonstrate the loading of both HG3T and antibodies can be achieved in a linear fashion so that quantitative assessment of antibodies and antigens is feasible. Our demonstration formats include: conventional multiwell plates, micropatterned electrodes, and fiber networks. We believe biologically based fabrication (i.e., biofabrication) provides bottom‐up hierarchical assembly of a variety of nanoscale components for applications that range from point‐of‐care diagnostics to smart fabrics. Biotechnol. Bioeng. 2009;103: 231–240. © 2008 Wiley Periodicals, Inc.     

Genetic influences on female infidelity and number of sexual partners in humans: a linkage and association study of the role of the vasopressin receptor gene (AVPR1A).

In humans, in contrast to animals, the genetic influences on infidelity are unclear. We report here a large study of over 1600 unselected United Kingdom female twin pairs who confidentially reported previous episodes of infidelity and total lifetime number of sexual partners, as well as attitudes towards infidelity. Our findings demonstrate that infidelity and number of sexual partners are both under moderate genetic influence (41% and 38% heritable, respectively) and the genetic correlation between these two traits is strong (47%). Conversely, attitudes towards infidelity are driven by shared and unique environmental, but not genetic, influences. A genome-wide linkage scan identified three suggestive but nonsignificant linkage areas associated with infidelity and number of sexual partners on chromosomes 3, 7 and 20 with a maximum LOD score of 2.46. We were unsuccessful in associating infidelity or number of sexual partners with a locus implicated in other mammals' sexual behavior, the vasopressin receptor gene. Nonetheless, our findings on the heritability of sexual infidelity and number of sexual partners provide support for certain evolutionary theories of human sexual behavior, as well as justifying further genetic and molecular research in this domain.     

Effects of receptor concentration, media pH and storage on nicotinic receptor-transmitted signal in a fiber-optic biosensor

The optical signal generated by a nicotinic acetylcholine receptor (nAChR)-based optical biosensor was dependent on the density of toxin binding sites (i.e. receptors) immobilized on the surface of the fiber. The maximum density of nAChR receptors absorbed on the optic fibers, measured using [125I]-alpha-bungarotoxin (the alpha-neurotoxin of the Bungarus snake venom) binding, was 6.2 pmol of receptor sites per fiber. Incubation time, that was required for maximal noncovalent immobilization of the receptor protein on the fiber, was less than 10 min. Immobilization of the nAChR protein on the quartz fiber was affected by pH of the medium, with pH 3.5 as the optimal. Stored in phosphate buffered saline (PBS) or in a dry nitrogen atmosphere, the nAChR optical sensor showed no loss of activity over the first 3 days, then showed a slow but gradual loss in activity (45% over the next 30 days).     

Calorimetric determination of polymerization enthalpy for bacterial flagellin (Salmonella)

The polymerization of bacterial flagellin protein (Salmonella strain SJ814) into flagellar filaments has been found by direct calorimetric measurement to be $\text{exothermic}$ at 25° in .15M KCl, pH 6.8 with a ΔH of ?12.7 ± 0.6 kcal per mole of monomer polymerized. The calorimetric result at 25° contrasts sharply with the endothermic ΔH of +38 kcal/mole inferred from temperature dependence of the critical monomer concentration near 40°C. Comparison between these two values implies that unless a different mechanism of polymerization prevails at the two temperatures the heat capacity change for flagellin polymerization may be as large as 3.3 kcal/mole deg.     

Behavior of the plasma level of digoxin in the rat in induced experimental hyperreninemia]

PRA, plasma and urine aldosterone levels and plasma digoxin were measured in rats in which digoxin had been administered under conditions of high PRA and high aldosterone levels experimentally induced by administering distilled water load and in rats in which digoxin had been administered without distilled water load. Results show that under conditions of high PRA and high aldosterone levels, plasma digoxin concentrations as measured 6 h after treatment were higher (45,3%) than in rats having received digoxin without water load. In assays carried out on rats sacrificed 12 h after digoxin treatment (with or without water load) all values approach basic levels again, thus suggesting that in rats too aldosterone might compete with digoxin at the level of tubular excretion.     

Granulation of digested sewage sludge in mesophilic UASB reactors treating distillery waste waters from sugar cane molasses

Five 4.02-1 UASB (Upflow Anaerobic Sludge Blanket) reactors were continuously operated at 30°C under different hydrodynamic regimes for more than 120 days. The effect of the upflow liquid velocity (ULV) over the range of 0.25 to 2.0 m/h on the biological characteristics of the granules formed by treating vinasses (waste water of alcohol distilleries) from sugar cane molasses was investigated constantly maintaining the volumetric loading rate (VLR) (8 g COD/l · d). Granular sludge was found at all the ULV tested. The size, shape, etc., of the granules indicated that the ULV had a considerable effect on the sludge cultivated in this type of system, thereby acting as a selection process for the biomass. The best results in relation to the time of appearance, size, shape, consistence, stability, composition, and the accumulation were observed in the ULV range between 0.25 and 0.5 m/h. Microscopic studies of the granules using optical and epifluorescence microscopes and the scanning electron micrograph (SEM) showed a heterogeneous biomass and revealed the cell characteristics.