Reduced transforming growth factor-beta signaling in cartilage of old mice: role in impaired repair capacity

Osteoarthritis (OA) is a common joint disease, mainly effecting the elderly population. The cause of OA seems to be an imbalance in catabolic and anabolic factors that develops with age. IL-1 is a catabolic factor known to induce cartilage damage, and transforming growth factor (TGF)-beta is an anabolic factor that can counteract many IL-1-induced effects. In old mice, we observed reduced responsiveness to TGF-beta-induced IL-1 counteraction. We investigated whether expression of TGF-beta and its signaling molecules altered with age. To mimic the TGF-beta deprived conditions in aged mice, we assessed the functional consequence of TGF-beta blocking. We isolated knee joints of mice aged 5 months or 2 years, half of which were exposed to IL-1 by intra-articular injection 24 h prior to knee joint isolation. Immunohistochemistry was performed, staining for TGF-beta1, -2 or -3, TGF-betaRI or -RII, Smad2, -3, -4, -6 and -7 and Smad-2P. The percentage of cells staining positive was determined in tibial cartilage. To mimic the lack of TGF-beta signaling in old mice, young mice were injected with IL-1 and after 2 days Ad-LAP (TGF-beta inhibitor) or a control virus were injected. Proteoglycan (PG) synthesis (³⁵S-sulfate incorporation) and PG content of the cartilage were determined. Our experiments revealed that TGF-beta2 and -3 expression decreased with age, as did the TGF-beta receptors. Although the number of cells positive for the Smad proteins was not altered, the number of cells expressing Smad2P strongly dropped in old mice. IL-1 did not alter the expression patterns. We mimicked the lack of TGF-beta signaling in old mice by TGF-beta inhibition with LAP. This resulted in a reduced level of PG synthesis and aggravation of PG depletion. The limited response of old mice to TGF-beta induced-IL-1 counteraction is not due to a diminished level of intracellular signaling molecules or an upregulation of intracellular inhibitors, but is likely due to an intrinsic absence of sufficient TGF-beta receptor expression. Blocking TGF-beta distorted the natural repair response after IL-1 injection. In conclusion, TGF-beta appears to play an important role in repair of cartilage and a lack of TGF-beta responsiveness in old mice might be at the root of OA development.     

Modeling climate change impacts on overwintering bald eagles

Bald eagles (Haliaeetus leucocephalus) are recovering from severe population declines, and are exerting pressure on food resources in some areas. Thousands of bald eagles overwinter near Puget Sound, primarily to feed on chum salmon (Oncorhynchus keta) carcasses. We used modeling techniques to examine how anticipated climate changes will affect energetic demands of overwintering bald eagles. We applied a regional downscaling method to two global climate change models to obtain hourly temperature, precipitation, wind, and longwave radiation estimates at the mouths of three Puget Sound tributaries (the Skagit, Hamma Hamma, and Nisqually rivers) in two decades, the 1970s and the 2050s. Climate data were used to drive bald eagle bioenergetics models from December to February for each river, year, and decade. Bald eagle bioenergetics were insensitive to climate change: despite warmer winters in the 2050s, particularly near the Nisqually River, bald eagle food requirements declined only slightly (<1%). However, the warming climate caused salmon carcasses to decompose more rapidly, resulting in 11% to 14% less annual carcass biomass available to eagles in the 2050s. That estimate is likely conservative, as it does not account for decreased availability of carcasses due to anticipated increases in winter stream flow. Future climate-driven declines in winter food availability, coupled with a growing bald eagle population, may force eagles to seek alternate prey in the Puget Sound area or in more remote ecosystems.     

Self‐Reported Body Mass Index and Health‐Related Quality of Life: Findings from the Behavioral Risk Factor Surveillance System

Objective: To examine the relationship between self‐reported body mass index (BMI) and health‐related quality of life in the general adult population in the United States. Research Methods and Procedures: Using data from 109,076 respondents in the 1996 Behavioral Risk Factor Surveillance System, we examined how self‐reported BMI is associated with five health‐related quality of life measures developed by the Centers for Disease Control and Prevention for population health surveillance. Results: After adjusting for age, gender, race or ethnicity, educational attainment, employment status, smoking status, and physical activity status, participants with a self‐reported BMI of <18.5 kg/m² and participants with a self‐reported BMI of ≥30 kg/m² reported impaired quality of life. Compared with persons with a self‐reported BMI of 18.5 to <25 kg/m², odds ratios (ORs) of poor or fair self‐rated health increased among persons with self‐reported BMIs of <18.5 (1.57, 95% confidence interval [CI]: 1.31 to 1.89), 25 to <30 kg/m² (1.12, 95% CI: 1.04 to 1.20), 30 to <35 kg/m² (1.65, 95% CI: 1.50 to 1.81), 35 to <40 kg/m² (2.58, 95% CI: 2.21 to 3.00), and ≥40 kg/m² (3.23, 95% CI: 2.63 to 3.95); ORs for reporting ≥14 days of poor physical health during the previous 30 days were 1.44 (95% CI: 1.21 to 1.72), 1.04 (95% CI: 0.96 to 1.14), 1.32 (95% CI: 1.19 to 1.47), 1.80 (95% CI: 1.52 to 2.13), and 2.37 (95% CI: 1.90 to 2.94), respectively; ORs for having ≥14 days of poor mental health during the previous 30 days were 1.18 (95% CI: 0.97 to 1.42), 1.02 (95% CI: 0.95 to 1.11), 1.22 (95% CI: 1.10 to 1.36), 1.68 (95% CI: 1.42 to 1.98), and 1.66 (95% CI: 1.32 to 2.09), respectively. Discussion: In the largest study to date, low and increased self‐reported BMI significantly impaired health‐related quality of life. Particularly, deviations from normal BMI affected physical functioning more strongly than mental functioning.     

Stability ofAlternaria toxins in fruit juices and wine

Alternaria alternata is a common fungal parasite on fruits and other plants and produces a number of mycotoxins, including alternariol (3,7,9-trihydroxy-1-methyl-6H-dibenzo [b,d]pyran-6-one), alternariol monomethyl ether (3,7-dihydroxy-9-methoxy-1-methyl-6H-dibenzo[b,d]pyran-6-one), and the mutagen altertoxin I {[1S-(1α,12aβ,12bα)] 1,2,11,12,12a, 12b-hexahydro-1,4,9,12a-tetrahydroxy-3,10-perylenedione}. Alternariol and alternariol monomethyl ether have previously been detected in some samples of fruit beverages. Stability studies of these toxins as well as altertoxin I added to fruit juices and wine (10–100 ng/mL) were carried out. To include altertoxin I in the analysis, cleanup with a polymer-based Varian Abselut solid phase extraction column was used, as recoveries from C-18 columns were low. The stabilities of alternariol and alternariol monomethyl ether in a low acid apple juice containing no declared vitamin C were compared with those in the same juice containing added vitamin C (60 mg/175 ml); there were no apparent losses at room temperature over 20 days or at 80°C after 20 min. in either juice. Altertoxin I was moderately stable in pH 3 buffer (75% remaining after a two week period). Furthermore, altertoxin I was stable or moderately stable in three brands of apple juice tested over 1–27 day periods and in a sample of red grape juice over 7 days. It is concluded that altertoxin I is sufficiently stable to be found in fruit juices and should be included in methods for alternariol and alternariol monomethyl ether.     

Inverse dispersal patterns in a group of ant parasitoids (Hymenoptera: Eucharitidae: Oraseminae) and their ant hosts

When postulating evolutionary hypotheses for diverse groups of taxa using molecular data, there is a tradeoff between sampling large numbers of taxa with a few Sanger-sequenced genes or sampling fewer taxa with hundreds to thousands of next-generation-sequenced genes. High taxon sampling enables the testing of evolutionary hypotheses that are sensitive to sampling bias (i.e. dating, biogeography and diversification analyses), whereas high character sampling improves resolution of critical nodes. In a group of ant parasitoids (Hymenoptera: Eucharitidae: Oraseminae), we analyse both of these types of datasets independently (203 taxa with five Sanger loci, 92 taxa with 348 anchored hybrid enrichment loci) and in combination (229 taxa, 353 loci) to explore divergence dating, biogeography, host relationships and differential rates of diversification. Oraseminae specialize as parasitoids of the immature stages of ants in the subfamily Myrmicinae (Hymenoptera: Formicidae), with ants in the genus Pheidole being their most common and presumed ancestral host. A general assumption is that the distribution of the parasite must be limited by any range contraction or expansion of its host. Recent studies support a single New World to Old World dispersal pattern for Pheidole at c. 11–27 Ma. Using multiple phylogenetic inference methods (parsimony, maximum likelihood, dated Bayesian and coalescent analyses), we provide a robust phylogeny showing that Oraseminae dispersed in the opposite direction, from Old World to New World, c. 24–33 Ma, which implies that they existed in the Old World before their presumed ancestral hosts. Their dispersal into the New World appears to have promoted an increased diversification rate. Both the host and parasitoid show single unidirectional dispersals in accordance with the presence of the Beringian Land Bridge during the Oligocene, a time when the changing northern climate probably limited the dispersal ability of such tropically adapted groups.     

Decline in American marten occupancy rates at Sagehen Experimental Forest,California

We compared the distribution and frequency of American marten (Martes americana) detections during historic surveys and a recent survey on the Sagehen Experimental Forest (SEF) in the Sierra Nevada Mountains, California. This area has been the location of 9 previous marten surveys during 1980–1993, each involving a systematic detection/non-detection survey on the same grid. These data are a time series of information on the occupancy of martens that can be related to habitat change in the study area. Our objectives were to 1) resurvey martens in SEF using methodology similar to previous studies to assess current marten occupancy; 2) evaluate changes in marten occupancy during the period 1980–2008; and 3) examine associations between marten occurence and changes in habitat and landscape metrics. Current marten occupancy was estimated using surveys conducted in summer 2007, winter 2007–2008, and summer 2008. From 1978 to 2007 there was a decrease in predicted habitat patch size, core area, and total amount of marten habitat in the study area, as well as an increase in distance between patches. Marten detections in 2007–2008 were approximately 60% lower than in surveys in the 1980s. We detected no martens in the summers of 2007 and 2008, and 10 detections in winter 2007–2008 were limited to higher elevations in the southwestern portion of SEF. No martens were detected in the lower elevations where most of the recent forest management activity occurred. We suggest that the marten population at SEF has been negatively affected by the loss and fragmentation of habitat. We recommend that future management of forests in the Sagehen basin focus on restoring and connecting residual marten habitat to improve habitat quality for martens. © 2011 The Wildlife Society.     

Bacteremia After Tooth Extractions Studied with the Aid of Prereduced Anaerobically Sterilized Culture Media

Both prereduced molten agar and broth and aerobic molten agar and broth were inoculated with blood samples collected from patients with periodontitis, but in otherwise good health, both before and after extraction of two or more teeth. Postoperative blood samples from 23 of 25 patients sampled yielded anaerobic and facultative species. Colony counts from nine samples yielded from less than 1 to over 100 colonies per ml of blood. Organisms detected were species belonging to the genera Bacteroides, Fusobacterium, Peptostreptococcus, Leptotrichia, Propionibacterium, Peptococcus, Veillonella, plus Streptococcus mitis, S. salivarius, vibrio forms, and strains resembling S. mutans. The data indicate that prereduced anaerobically sterilized culture medium with polyanethol sulfonate is effective for detecting anaerobic species in bacteremia and that anaerobic species can be prevalent in bacteremias immediately after tooth extraction in patients with periodontitis.     

Deformation of the diastolic left ventricle—II. Nonlinear geometric effects

A finite element model for the rat left ventricle has been developed which is based on finite deformation elasticity theory: i.e. the model is not limited by assumptions relating to the magnitudes of extensions, shears and angles of rotation which are inherent in the classical theory of elasticity. This model represents the ventricle as a heterogeneous, nonlinearly elastic, isotropic thick-wall solid of revolution. For the representation of myocardial elasticity used in this study, the model predicts overall ventricular stiffnesses at physiological pressures which are 20–30 per cent lower than those obtained with a model based on the classical theory. However, extentions predicted by the two theories differ by as much as 100 per cent in certain portions of the ventricular wall.