Heat shock protein-27 attenuates foam cell formation and atherogenesis by down-regulating scavenger receptor-A expression via NF-κB signaling

Previously, we showed an inverse correlation between HSP27 serum levels and experimental atherogenesis in ApoE^?/? mice that over-express HSP27 and speculated that the apparent binding of HSP27 to scavenger receptor-A (SR-A) was of mechanistic importance in attenuating foam cell formation. However, the nature and importance of the interplay between HSP27 and SR-A in atheroprotection remained unclear. Treatment of THP-1 macrophages with recombinant HSP27 (rHSP27) inhibited acLDL binding (? 34%; p < 0.005) and uptake (? 38%, p < 0.05). rHSP27 reduced SR-A mRNA (? 39%, p = 0.02), total protein (? 56%, p = 0.01) and cell surface (? 53%, p < 0.001) expression. The reduction in SR-A expression by rHSP27 was associated with a 4-fold increase in nuclear factor-kappa B (NF-κB) signaling (p < 0.001 versus control), while an inhibitor of NF-κB signaling, BAY11-7082, attenuated the negative effects of rHSP27 on both SR-A expression and lipid uptake. To determine if SR-A is required for HSP27 mediated atheroprotection in vivo, ApoE^?/? and ApoE^?/? SR-A^?/? mice fed with a high fat diet were treated for 3 weeks with rHSP25. Compared to controls, rHSP25 therapy reduced aortic en face and aortic sinus atherosclerotic lesion size in ApoE^?/? mice by 39% and 36% (p < 0.05), respectively, but not in ApoE^?/?SR-A^?/? mice. In conclusion, rHSP27 diminishes SR-A expression, resulting in attenuated foam cell formation in vitro. Regulation of SR-A by HSP27 may involve the participation of NF-κB signaling. Lastly, SR-A is required for HSP27-mediated atheroprotection in vivo.     

Occurrence of faecal contamination in households along the US-Mexico border

Aims:  The study aim was to determine the presence of total and faecal coliforms on kitchen surfaces, in tap water and on the hands of caregivers in households on both sides of the US–Mexico border.
Methods and Results:  Samples were collected in 135 randomly selected households in Ciudad Juarez, Mexico, and El Paso, Texas. Different surfaces throughout the kitchen and head of households' hands were sampled using sterile cotton swabs moistened in D/E neutralizing solution. Sponge/dishcloth and drinking water samples were also obtained. Total and faecal coliforms were enumerated on m-Endo LES and mFC respectively. Total coliforms and Escherichia coli in drinking water samples were enumerated in accordance with the Quanti-Tray^TM method. Sponge/dishcloth samples were the most commonly contaminated kitchen sites, followed by countertops and cutting boards. We recovered faecal coliforms from 14% of the hands of child caregivers, and this indicator was moderately associated with self-reported failure to wash hands after using the toilet (OR = 3·2; 95% CI: 0·9, 11·1).
Conclusions:  Hand washing should continue to be emphasized, and additional interventions should be directed to specific kitchen areas, such as sponges/dishcloths, tables/countertops and cutting boards.
Significance and Impact of the Study:  There is a need for additional interventions regarding kitchen sanitation.     

The effect of muscle flap transposition to the fracture site on TNFalpha levels during fracture healing

The trauma and sepsis that follow open fractures and wounds may lead to the production of various cytokines. Understanding wound healing requires a direct knowledge of the specific cytokines and the respective wound fluid levels that are present at the wound site. An animal model was designed that mimics the open fracture and the clinical repair of the human, high-energy open fracture. Canine right tibiae were fractured with a penetrating, captive-bolt device, then repaired in a standard clinical fashion using an interlocking intramedullary nail. Before primary wound closure, microdialysis probes were placed at the fracture site and in a muscle located at a contralateral site. Canines received one of the following experimental protocols: (1) tibial fracture (n = 5); (2) tibial fracture plus Staphylococcus aureus inoculation at the fracture site (n = 5); and (3) tibial fracture, S. aureus inoculation, and a rotational gastrocnemius muscle flap (n = 5). Microdialysis fluid samples were collected intermittently for 7 days. Tumor necrosis factor alpha (TNFalpha) levels at the fracture site were significantly elevated 3 to 34-fold (p<0.02), as compared with respective serum levels at all time points for all treatment groups. Fracture site TNFalpha levels were elevated (p<0.02) in days 1 through 6, as compared with the baseline and contralateral in all treatment groups. At days 1 through 6, the TNFalpha levels of the muscle flap group fracture site were significantly decreased by approximately 50 percent (p<0.05), as compared with the fractures without muscle flaps and regardless of additional S. aureus inoculation. On day 7, fracture site TNFalpha levels in all animal groups were similar, yet remained well above those of baseline TNFalpha. These results demonstrate that S. aureus does not further elevate TNFalpha levels in the presence of an open fracture and that a muscle flap reduces pro-inflammatory TNFalpha levels during early wound healing. This experimental model allows for the characterization of specific biological signals and cellular pathways that are influenced by bacterial infection and surgical closure. These data provide a scientific framework on which to judge or validate therapeutic regimens for open-fracture wound healing.     

Ultrasonic Vocalizations Emitted by Flying Squirrels

Anecdotal reports of ultrasound use by flying squirrels have existed for decades, yet there has been little detailed analysis of their vocalizations. Here we demonstrate that two species of flying squirrel emit ultrasonic vocalizations. We recorded vocalizations from northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels calling in both the laboratory and at a field site in central Ontario, Canada. We demonstrate that flying squirrels produce ultrasonic emissions through recorded bursts of broadband noise and time-frequency structured frequency modulated (FM) vocalizations, some of which were purely ultrasonic. Squirrels emitted three types of ultrasonic calls in laboratory recordings and one type in the field. The variety of signals that were recorded suggest that flying squirrels may use ultrasonic vocalizations to transfer information. Thus, vocalizations may be an important, although still poorly understood, aspect of flying squirrel social biology.     

Relatively simple methodology for the determination of configuration of unsaturation of bacterial monounsaturated fatty acids: application to the unsaturates of Legionella spp.

Unsaturated fatty acids of known degree, position, and configuration of unsturation were esterified, and stereospecifically dihydroxylated at the double bond(s). cis-Hydroxylation was effected using Woodward's reagent (silver acetate/iodine/acetic acid), while trans-hydroxylation was effected using Fenton's reagent (hydrogen peroxide/ferrous sulfate/acetic acid). Diols derived from monounsaturated esters were recovered quantitatively, while tetraols derived from diunsaturates were lost, presumably during extensive washing. The stereospecifically dihydroxylated esters were analyzed by thin-layer chromatography on borate-impregnated silica gel plates, and by gas-liquid chromatography, on a nonpolar capillary column, as the trimethylsilyl, acetyl, n-butylboronyl, isopropylidene, and trifluoroacetyl derivatives. For each derivative, the erythro and threo diols were readily separable, and some resolution of positional isomers was observed. Thus, the cis/trans configuration, and in some instances, the position of unsaturation of the original monounsaturated fatty acid may be deduced. However, gas chromatography-mass spectrometry of appropriately derivatized diol esters is required for unambiguous determination of position of unsaturation in most cases. These reactions are simple, use readily available reagents, and require relatively little operator attention. Further, they do not require specialized apparatus, as do hydrogenation and ozonolysis, or potentially toxic chemicals, such as osmium tetroxide. This series of analyses was applied to the unsaturated non-hydroxylated fatty acids of Legionella species, which were shown to be monounsaturated and of the cis Δ9 family. Position of unsaturation was confirmed by gas chromatography-mass spectrometry.     

H3K4 demethylase activities repress proliferative and postmitotic aging

Homeostasis of postmitotic and proliferating cells is maintained by pathways that repress stress. We found that the Caenorhabditis elegans histone 3 lysine 4 (H3K4) demethylases RBR‐2 and SPR‐5 promoted postmitotic longevity of stress‐resistant daf‐2 adults, altered pools of methylated H3K4, and promoted silencing of some daf‐2 target genes. In addition, RBR‐2 and SPR‐5 were required for germ cell immortality at a high temperature. Transgenerational proliferative aging was enhanced for spr‐5; rbr‐2 double mutants, suggesting that these histone demethylases may function sequentially to promote germ cell immortality by targeting distinct H3K4 methyl marks. RBR‐2 did not play a comparable role in the maintenance of quiescent germ cells in dauer larvae, implying that it represses stress that occurs as a consequence of germ cell proliferation, rather than stress that accumulates in nondividing cells. We propose that H3K4 demethylase activities promote the maintenance of chromatin states during stressful growth conditions, thereby repressing postmitotic aging of somatic cells as well as proliferative aging of germ cells.