The effect of vasoactive intestinal peptide (VIP) and naloxone combination on survival rates in rats exposed to severe hemorrhage.

In this experiment, the effects of different doses of vasoactive intestinal peptide (VIP) and naloxone (NLX) combinations on survival rates were investigated in rats exposed to 40% hemorrhage. A combination of 25 ng.kg-1 VIP+5 mg.kg-1 NLX showed the best results on survival. The important prospect of this combination is to have the most potent inhibitory effect on mast cell degranulation. When this combination was given together with shed blood reperfusion and 7.5% NaCl, survival rate increased relative to the administration of shed blood alone and of 7.5% NaCl. These findings suggest that inhibition of mast cell degranulation has a beneficial effect on severe hemorrhage.     

Nonionic, Water Self-Dispersible "Hairy-Rod" Poly(p-phenylene)-g-poly(ethylene glycol) Copolymer/Carbon Nanotube Conjugates for Targeted Cell Imaging

The generation and fabrication of nanoscopic structures are of critical technological importance for future implementations in areas such as nanodevices and nanotechnology, biosensing, bioimaging, cancer targeting, and drug delivery. Applications of carbon nanotubes (CNTs) in biological fields have been impeded by the incapability of their visualization using conventional methods. Therefore, fluorescence labeling of CNTs with various probes under physiological conditions has become a significant issue for their utilization in biological processes. Herein, we demonstrate a facile and additional fluorophore-free approach for cancer cell-imaging and diagnosis by combining multiwalled CNTs with a well-known conjugated polymer, namely, poly(p-phenylene) (PP). In this approach, PP decorated with poly(ethylene glycol) (PEG) was noncovalently (π-π stacking) linked to acid-treated CNTs. The obtained water self-dispersible, stable, and biocompatible f-CNT/PP-g-PEG conjugates were then bioconjugated to estrogen-specific antibody (anti-ER) via -COOH functionalities present on the side-walls of CNTs. The resulting conjugates were used as an efficient fluorescent probe for targeted imaging of estrogen receptor overexpressed cancer cells, such as MCF-7. In vitro studies and fluorescence microscopy data show that these conjugates can specifically bind to MCF-7 cells with high efficiency. The represented results imply that CNT-based materials could easily be fabricated by the described approach and used as an efficient "fluorescent probe" for targeting and imaging, thereby providing many new possibilities for various applications in biomedical sensing and diagnosis.     

Porphyromonas gingivalis Strain Specific Interactions with Human Coronary Artery Endothelial Cells: A Comparative Study

Both epidemiologic and experimental findings suggest that infection with Porphyromonas gingivalis exacerbates progression of atherosclerosis. As P. gingivalis exhibits significant strain variation, it is reasonable that different strains possess different capabilities and/or mechanisms by which they promote atherosclerosis. Using P. gingivalis strains that have been previously evaluated in the ApoE null atherosclerosis model, we assessed the ability of W83, A7436, 381, and 33277 to adhere, invade, and persist in human coronary artery endothelial (HCAE) cells. W83 and 381 displayed an equivalent ability to adhere to HCAE cells, which was significantly greater than both A7436 and 33277 (P<0.01). W83, 381, and 33277 were more invasive than A7436 (P<0.0001). However, only W83 and A7436 were able to remain viable up to 48 hours in HCAE cell cultures, whereas 381 was cleared by 48 hours and 33277 was cleared by 24 hours. These differences in persistence were in part due to strain specific differences in intracellular trafficking. Both W83 and 381 trafficked through the autophagic pathway, but not A7436 or 33277. Internalized 381 was the only strain that was dependent upon the autophagic pathway for its survival. Finally, we assessed the efficacy of these strains to activate HCAE cells as defined by production of IL-6, IL-8, IL-12p40, MCP-1, RANTES, TNF-α, and soluble adhesion molecules (sICAM-1, sVCAM-1, and sE-selectin). Only moderate inflammation was observed in cells infected with either W83 or A7436, whereas cells infected with 381 exhibited the most profound inflammation, followed by cells infected with 33277. These results demonstrate that virulence mechanisms among different P. gingivalis strains are varied and that pathogenic mechanisms identified for one strain are not necessarily applicable to other strains.     

Comprehensive evaluation of canonical versus Dicer-substrate siRNA in vitro and in vivo

Since the discovery of RNA interference (RNAi), researchers have identified a variety of small interfering RNA (siRNA) structures that demonstrate the ability to silence gene expression through the classical RISC-mediated mechanism. One such structure, termed "Dicer-substrate siRNA" (dsiRNA), was proposed to have enhanced potency via RISC-mediated gene silencing, although a comprehensive comparison of canonical siRNAs and dsiRNAs remains to be described. The present study evaluates the in vitro and in vivo activities of siRNAs and dsiRNAs targeting Phosphatase and Tensin Homolog (PTEN) and Factor VII (FVII). More than 250 compounds representing both siRNA and dsiRNA structures were evaluated for silencing efficacy. Lead compounds were assessed for duration of silencing and other key parameters such as cytokine induction. We identified highly active compounds from both canonical siRNAs and 25/27 dsiRNAs. Lead compounds were comparable in potency both in vitro and in vivo as well as duration of silencing in vivo. Duplexes from both structural classes tolerated 2'-OMe chemical modifications well with respect to target silencing, although some modified dsiRNAs demonstrated reduced activity. On the other hand, dsiRNAs were more immunostimulatory as compared with the shorter siRNAs, both in vitro and in vivo. Because the dsiRNA structure does not confer any appreciable benefits in vitro or in vivo while demonstrating specific liabilities, further studies are required to support their applications in RNAi therapeutics.     

Ghrelin immunohistochemistry of gastric adenocarcinoma and mucoepidermoid carcinoma of salivary gland

Ghrelin (G-HH) synthesized in several tissues including salivary and stomach glands stimulates appetite in humans by modulating neuropeptide Y neurons in the hypothalamic arcuate nucleus. Loss of appetite is one of the most important symptoms of stomach cancer. We conducted a study using immunohistochemistry to determine whether salivary glands and stomach cancer tissues produce ghrelin. We determined that negative ghrelin immunohistochemistry discriminates tumors from normal tissues and may therefore further our understanding of the clinically important problem of reduced food intake and anorexia in cancer patients. Radioimmunoassay analyses confirmed that cancer cells do not produce a G-HH peptide, whereas normal cells yield this peptide.     

Structural and chemical properties of grass lignocelluloses related to conversion for biofuels

Grass lignocelluloses, such as those in corn and switchgrass, are a major resource in the emerging cellulose-to-ethanol strategy for biofuels. The potential bioconversion of carbohydrates in this potential resource, however, is limited by the associated aromatic constituents within the grass fiber. These aromatics include both lignins, which are phenylpropanoid units of various types, and low-molecular weight phenolic acids. Structural and chemical studies over the years have identified the location and limitation to fiber degradation imposed by a variety of these aromatic barriers. For example, coniferyl lignin appears to be the most effective limitation to biodegradation, existing in xylem cells of vascular tissues. On the other hand, cell walls with syringyl lignin, e.g., leaf sclerenchyma, are often less recalcitrant. Ferulic and p-coumaric acids that are esterified to hemicellulosic sugars constitute a major limitation to biodegradation in non-lignified cell walls in grass fibers, especially warm season species. Non-chemical methods to improve bioconversion of the lignocelluloses through modification of aromatics include: (1) use of lignin-degrading white rot fungi, (2) pretreatment with phenolic acid esterases, and (3) plant breeding to modify cell wall aromatics. In addition to increased availability of carbohydrates for fermentation, separation and collection of aromatics could provide value-added co-products to improve the economics of bioconversion. JIMB-2008: BioEnergy—Special issue.     

Heme oxygenase-1 is an anti-inflammatory host factor that promotes murine plasmodium liver infection

The clinically silent Plasmodium liver stage is an obligatory step in the establishment of malaria infection and disease. We report here that expression of heme oxygenase-1 (HO-1, encoded by Hmox1) is upregulated in the liver following infection by Plasmodium berghei and Plasmodium yoelii sporozoites. HO-1 overexpression in the liver leads to a proportional increase in parasite liver load, and treatment of mice with carbon monoxide and with biliverdin, each an enzymatic product of HO-1, also increases parasite liver load. Conversely, mice lacking Hmox1 completely resolve the infection. In the absence of HO-1, the levels of inflammatory cytokines involved in the control of liver infection are increased. These findings suggest that, while stimulating inflammation, the liver stage of Plasmodium also induces HO-1 expression, which modulates the host inflammatory response, protecting the infected hepatocytes and promoting the liver stage of infection.     

Building flax fibres: more than one brick in the walls

The objective of the review is to provide fundamental knowledge on the chemical composition and structural characteristics of flax fibres. These are long and multinucleate cells without septum or partition (average length 2–5 cm) and have a secondary wall of very large thickness (5–15 μm). Fibres are gathered in bundles of one to three dozen cells that encircle the vascular cylinder. The bundle cohesion is insured by pectins, accumulating in the primary wall and cell junctions. In contrast, lignin, which is present in very low amount, does not seem to play a major role in bundle cohesion. At maturity, secondary wall is characterised by (i) a high level of cellulose with microfibrils locked into an almost axial direction and (ii) 5–15% non-cellulosic polysaccharides (NCPs). The chemical composition of NCPs depends on growth stage, indicating important cell wall remodelling, fibre position and variety. Despite the large disparity of the results reported in the literature, galactose appears to be the predominant sugar of NCPs, and β-1-4-galactan together with rhamnogalacturonan of type I (RG-I) and polygalacturonic acid (PGA) become, with fibre maturity, the most abundant tightly bound NCPs. Glycine-rich proteins (GRPs) and arabinogalactan-proteins (AGPs), also present in flax fibres, are both characterised by appreciable levels of glycine and acidic amino acid and are deficient in hydroxyproline, and may contribute to the cross-linking of pectins. (Galacto)glucomanans/glucans rather than xylans consist of cross-linking polymers in fibre secondary wall. A model is proposed where cellulose microfibrils, tethered by cross-linking (galacto)glucomanans/glucans, are embedded in a pectic matrix.     

GEOGRAPHIC VARIATION IN TOOTH MORPHOLOGY AND DENTINAL PATTERNS IN THE SPINNER DOLPHIN, STENELLA LONGIROSTRIS

Sixteen tooth characters were analyzed in 277 specimens of spinner dolphins ( Stenella longirostris ) from the eastern tropical Pacific to determine whether the characters were associated with size of the animal, species-stock membership or geographic location. The tooth characters included 5 continuous measurements and 11 qualitative variables. Statistical analyses of the characters included two-way ANOVA tests which assessed continuous measurement variables for differences based on stock membership, latitude and longitude of collection or whether the animal was collected north or south of the equator. Principal component analyses combined factors of continuous variables with those of qualitative variables into components which were used as variables in further analyses. Discriminant analyses were performed using continuous variables alone and using principal components as potentially discriminating variables. Results showed that tooth differences were not associated with size but significant differences were found in some tooth variables with stock membership, incremental changes in latitude and whether the animal was collected north or south of the equator. A discriminant function, containing only tooth length, correctly classified 67% of northern and 78% of southern animals according to location of collection north or south of the equator.     

Rumen bacterial and fungal degradation of Digitaria pentzii grown with or without sulfur.

Sheep fed the forage Digitaria pentzii fertilized with sulfur were compared with those fed unfertilized forage for the rumen microbial population involved with fiber degradation. No differences were detected in the bacterial population as determined by anaerobic cultures on a habitat-simulating medium, xylan, or pectin, by 35S labeling techniques for microbial protein, or by transmission electron microscopic studies of bacterium-fiber interactions. Rumen volume and water flow from the rumen were not different for sheep fed each of the forages. Rumen fungi were prevalent in sheep fed sulfur-fertilized D. pentzii as shown by sporangia adhering to forage fiber and by colonies developing from zoospores in roll tubes with cellobiose plus streptomycin and penicillin. Fungi were absent or in extremely small numbers in sheep fed unfertilized forage. Nylon bag digestibility studies showed that the fungi preferentially colonized the lignified cells of blade sclerenchyma by 6 h and caused extensive degradation by 24 h. In the absence of bacteria in in vitro studies, extensive hyphal development occurred; other lignified tissues in blades (i.e., mestome sheath and xylem) were attacked, resulting in a residue with partially degraded and weakened cell walls. Nonlignified tissues were also degraded. Breaking force tests of leaf blades incubated in vitro with penicillin and streptomycin and rumen fluid from sheep fed sulfur-fertilized forage or within nylon bags in such sheep showed a residue at least twice as fragile as that from sheep fed unfertilized forage. In vitro tests for dry matter loss showed that rumen fungi, in the absence of actively growing bacteria, could remove about 62% of the forage material. The response of rumen fungi in sheep fed sulfur-fertilized D. pentzii afforded a useful in vivo test to study the role of these microbes in fiber degradation. Our data establish that rumen fungi can be significant degraders of fiber and further establish a unique role for them in attacking and weakening lignocellulosic tissues. The more fragile residues resulting from attack by fungi could explain the greater intake consistently observed by sheep eating sulfur-fertilized compared with unfertilized D. pentzii forage.