ANGIOTENSIN AT2R ACTIVATION INCREASES ACE2/ANG1-7/MASR AXIS AND PREVENTS FATTY-DIET-INDUCED OBESITY

Purpose: Adipose tissue, the obligatory site of fat accumulation causing obesity, expresses local renin angiotensin system (RAS). RAS is commonly known to regulate blood pressure. However recently, we observed that angiotensin type 2 receptor (AT2R) activation prevents high-fat diet (HFD)-induced adiposity and hyperinsulinemia. Although, the mechanism(s) is(are) not known. There is evidence that other RAS components namely, the angiotensin type 1 receptor (AT1R) positively regulates while the angiotensin converting enzyme 2 (ACE2), which catalyzes the production of Mas receptor (MasR) peptide agonist Ang (1-7), inversely regulates adiposity and hyperinsulinemia. In light of the RAS inter-regulatory features, we hypothesize that AT2R activation causes a decrease in AT1R expression and an increase in the ACE2/Ang (1-7)/MasR expression in adipose tissue exerting beneficial effects on HFD-induced adiposity. Method: Male C57BL/6 mice (12-weeks old) were pretreated with AT2R agonist (C21, 0.3 mg/kg, daily i.p.) for 4 days. Thereafter, the animals were placed on normal chow diet (ND) or HFD with concurrent drug treatment for next 10 days. Results: The HFD increased the epididymal white adipose tissue (eWAT) weight, plasma free fatty acid (FFA), triglyceride (TG) and insulin levels. The increase in these parameters was prevented by C21 treatment. Western blot analysis demonstrated that HFD increased the protein expressions of AT1R and ACE, but decreased Ang (1-7) peptide level as measured by LC/MS analysis in eWAT. The C21 treatment under HFD condition caused a significant decreased in protein expressions of eWAT AT1R and ACE, but an increase in the expressions of MasR, ACE2 and ANG(1-7) peptide level. Conclusions: The pharmacological activation of AT2R with C21 affects adipose RAS components i.e., an increase in ACE2/Ang(1-7)/MasR levels and a decrease in ACE/AT1R expression, improving lipid metabolism and hyperinsulinemia under HFD condition. We propose that the pharmacological activation of AT2R may serve as therapeutic target for controlling obesity and associated metabolic disorders. Supported in part by grant from the NIH (RO1 DK-61578) to Dr. Hussain. Key Words: angiotensin receptors, angiotensin converting enzyme 2, obesit

Straw blood cell count, growth, inhibition and comparison to apoptotic bodies

<p>Abstract</p> <p>Background</p> <p>Mammalian cells transform into individual tubular straw cells naturally in tissues and in response to desiccation related stress <it>in vitro</it>. The transformation event is characterized by a dramatic cellular deformation process which includes: condensation of certain cellular materials into a much smaller tubular structure, synthesis of a tubular wall and growth of filamentous extensions. This study continues the characterization of straw cells in blood, as well as the mechanisms of tubular transformation in response to stress; with specific emphasis placed on investigating whether tubular transformation shares the same signaling pathway as apoptosis.</p> <p>Results</p> <p>There are approximately 100 billion, unconventional, tubular straw cells in human blood at any given time. The straw blood cell count (SBC) is 45 million/ml, which accounts for 6.9% of the bloods dry weight. Straw cells originating from the lungs, liver and lymphocytes have varying nodules, hairiness and dimensions. Lipid profiling reveals severe disruption of the plasma membrane in CACO cells during transformation. The growth rates for the elongation of filaments and enlargement of rabbit straw cells is 0.6~1.1 (μm/hr) and 3.8 (μm³/hr), respectively. Studies using apoptosis inhibitors and a tubular transformation inhibitor in CACO2 cells and in mice suggested apoptosis produced apoptotic bodies are mediated differently than tubular transformation produced straw cells. A single dose of 0.01 mg/kg/day of p38 MAPK inhibitor in wild type mice results in a 30% reduction in the SBC. In 9 domestic animals SBC appears to correlate inversely with an animal's average lifespan (R²= 0.7).</p> <p>Conclusion</p> <p>Straw cells are observed residing in the mammalian blood with large quantities. Production of SBC appears to be constant for a given animal and may involve a stress-inducible protein kinase (P38 MAPK). Tubular transformation is a programmed cell survival process that diverges from apoptosis. SBCs may be an important indicator of intrinsic aging-related stress.</p

Capillary-channeled polymeric fiber as solid phase extraction media

Solid phase extraction devices including a plurality of packed nominally aligned capillary-channeled polymeric fibers for use as stationary phase materials are disclosed. A plurality of fibers are packed together in a casing so as to provide good flow characteristics through the fibers and high surface area contact between a sample and the fibers. Different polymer compositions of the fibers permit the chemical tuning of the extraction process. The fibers can be physically or chemically derivatized to target specific analytes for separation from a test sample. Use of the fibers allows a wide range of liquid flow rates with very low backpressures. The fibers are easily packed into a micropipette tip or a conduit for use with a fluid flow device such as an aspirator or a pump. The devices can be used for isolation and pre-concentration of analytes from samples, for instance for proteins from buffer solutions or extraction of pollutants from remote locations

Mechanism of Photolytic Decomposition of N-Halamine Antimicrobial Siloxane Coatings

Generally, antimicrobial N halamine siloxane coatings can be rehalogenated repetitively upon loss of their biocidal efficacies, a marked advantage over coatings containing other antimicrobial materials. However, the N halamine materials tend to slowly decompose upon exposure to ultraviolet irradiation as in direct sunlight. In this work the mechanism of photolytic decomposition for the N halamine siloxanes has been studied using spectroscopic and theoretical methods. It was found that the N chlorinated coatings slowly decomposed upon UVA irradiation, whereas the unhalogenated coatings did not. Model compound evidence in this work suggests that upon UVA irradiation, the N-Cl bond dissociates homolytically, followed by a Cl radical migration to the alkyl side chain connected to the siloxane tethering group. An alpha and/or beta scission then occurs causing partial loss of the biocidal moiety from the surface of the coated material thus precluding complete rechlorination. NMR, FTIR, GCMS, and computation at the DFT (U)B3LYP/6-311++G(2d,p) level of theory have been employed in reaching this conclusion

Adsorption-Induced Changes in Ribonuclease A Structure and Enzymatic Activity on Solid Surfaces

Ribonuclease A (RNase A) is a small globular enzyme that lyses RNA. The remarkable solution stability of its structure and enzymatic activity has led to its investigation to develop a new class of drugs for cancer chemotherapeutics. However, the successful clinical application of RNase A has been reported to be limited by insufficient stability and loss of enzymatic activity when it was coupled with a biomaterial carrier for drug delivery. The objective of this study was to characterize the structural stability and enzymatic activity of RNase A when it was adsorbed on different surface chemistries (represented by fused silica glass, high-density polyethylene, and poly­(methyl-methacrylate)). Changes in protein structure were measured by circular dichroism, amino acid labeling with mass spectrometry, and in vitro assays of its enzymatic activity. Our results indicated that the process of adsorption caused RNase A to undergo a substantial degree of unfolding with significant differences in its adsorbed structure on each material surface. Adsorption caused RNase A to lose about 60% of its native-state enzymatic activity independent of the material on which it was adsorbed. These results indicate that the native-state structure of RNase A is greatly altered when it is adsorbed on a wide range of surface chemistries, especially at the catalytic site. Therefore, drug delivery systems must focus on retaining the native structure of RNase A in order to maintain a high level of enzymatic activity for applications such as antitumor chemotherapy

Inhibitory Activity of Carbonyl Compounds on Alcoholic Fermentation by Saccharomyces cerevisiae

Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and <i>o</i>-phthalaldehyde) were used to examine the quantitative structure–inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and <i>o</i>-phthalaldehyde (5.0 mM) reduced the initial glucose consumption rate by 60 and 89%, respectively, and also decreased the final ethanol yield by 60 and 99%, respectively. Correlating the molecular descriptors to inhibition efficiency in yeast fermentation revealed a strong relationship between the energy of the lowest unoccupied molecular orbital (<i>E</i>_LUMO) of aldehydes and their inhibitory efficiency in fermentation. On the other hand, vanillin, syringaldehyde, and 4-hydroxybenzaldehyde (5.0 mM) increased the final ethanol yields by 11, 4, and 1%, respectively. Addition of vanillin appeared to favor ethanol formation over glycerol formation and decreased the glycerol yield in yeast fermentation. Furthermore, alcohol dehydrogenase (ADH) activity dropped significantly from 3.85 to 2.72, 1.83, 0.46, and 0.11 U/mg at 6 h of fermentation at vanillin concentrations of 0, 2.5, 5.0, 10.0, and 25.0 mM correspondingly. In addition, fermentation inhibition by acetic acid and benzoic acid was pH-dependent. Addition of acetate, benzoate, and potassium chloride increased the glucose consumption rate, likely because the salts enhanced membrane permeability, thus increasing glucose consumption

Straw blood cell count, growth, inhibition and comparison to apoptotic bodies-4

2 cells that were transformed into straw cells. . Regeneration of regular cells from straw cells, three proteins at 63, 57, and 52 KD were abundantly expressed in the early stage of the process.<p><b>Copyright information:</b></p><p>Taken from "Straw blood cell count, growth, inhibition and comparison to apoptotic bodies"</p><p>http://www.biomedcentral.com/1471-2121/9/26</p><p>BMC Cell Biology 2008;9():26-26.</p><p>Published online 20 May 2008</p><p>PMCID:PMC2397387.</p><p></p

Straw blood cell count, growth, inhibition and comparison to apoptotic bodies-2

Bular transformation induced by dehydration. DNA ladder did appear (right panel) in CACO2 cells during a failed tubular transformation . Measurement of caspase-3/7 activity during dehydration induced tubular transformation in CACO2 cells. . Inhibition of tubular transformation by small molecules in vivo. Blood samples are counted from a single dose sc at 24 hr.<p><b>Copyright information:</b></p><p>Taken from "Straw blood cell count, growth, inhibition and comparison to apoptotic bodies"</p><p>http://www.biomedcentral.com/1471-2121/9/26</p><p>BMC Cell Biology 2008;9():26-26.</p><p>Published online 20 May 2008</p><p>PMCID:PMC2397387.</p><p></p