Nanoparticle surface energy transfer (NSET) in ferroelectric liquid crystal-metallic-silver nanoparticle composites: Effect of dopant concentration on NSET parameters

In the recent past, the resonance energy transfer studies using metallic nanoparticles has become a matter of quintessence in modern technology, which considerably extends its applications in probing specific biological and chemical processes. In the present study, metallic-silver nanoparticles of 2-4 nm (diameter) capped with hexanethiol ligand are developed and dispersed in ferroelectric liquid crystal (FLC). The morphology of nanoparticles was characterized using HR-TEM and SEM techniques. Furthermore, a systematic study of energy transfer between the host FLC material (as donors) and metallic-silver nanoparticles (as acceptors) has been explored employing steady state and time resolved fluorescence spectroscopic techniques. The nanoparticle based surface energy transfer (NSET) parameters viz., transfer efficiency, transfer rate, and proximity distance between donor and acceptor, have been determined for NSET couples (FLC material-metallic-silver nanoparticle) composites. It is observed that various NSET parameters and quenching efficiency follow a linear dependence on the concentration of metallic-silver nanoparticles in host FLC material. The nonradiative energy transfer and superquenching effect were analyzed with the help of Stern-Volmer plots. The impact of present study about superquenching effect of the silver nanoparticles can be used for sensing applications that require high degree sensitivity.

Crystal structure of 4,5,6,7,8,8-hexa-chloro-2-(3,4-di-meth-oxy-pheneth-yl)-3a,4,7,7a-tetra-hydro-1H-4,7-methano-iso-indole-1,3(2H)-dione [+solvent]

In the title compound, C19H15Cl6NO4 [+solvent], the six-membered ring of the norbornene moiety adopts a boat conformation and the two five-membered rings have envelope conformations. The pyrrolidine ring makes a dihedral angle of 14.83 (12)° with the 3,4-di-meth-oxy-phenyl ring, which are attached to each other by an extended N-CH2-CH2-Car bridge. In the crystal, the structure features C-H⋯O inter-molecular hydrogen bonds, an offset π-π inter-action [inter-centroid distance = 3.564 (1) Å] and a C-Cl⋯π inter-action. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9-18] of PLATON. The solvent contribution was not included in the reported mol-ecular weight and density.

Structural insights and binding of a natural ligand, succinic acid with serine and cysteine proteases

In the age of growing infectious diseases, there is a great demand for new inhibitors which can exhibit minimum side effects. Owing to the importance of proteases in life cycle and invasion, they have been projected as attractive targets for structure based drug designing against microbes including viruses. Here we report the inhibitory activity of a well known natural compound succinic acid against both serine and cysteine proteases. The ligand is found co-crystallized with Bovine pancreatic trypsin in one of our crystallization trials and the diffraction data up to1.9 Å reveal its interactions with the catalytic triad residues Histidine 57 and Serine 195. Binding of the ligand with these proteases have been validated using caseinolysis inhibition. With trypsin, ITC analysis showed tight binding of the ligand, resulting in change in Gibb's free energy (ΔG) by -20.31 kJ/mol. To understand the existence of succinic acid at the active site, molecular docking was performed and it revealed binding of it with trypsin and papain at corresponding active sites. This dual inhibitory activity of natural ligand, succinic acid can be accounted for the recent reports on anti-viral property of plant extracts where dicarboxilic fatty acids are normally abundant.

Effect of graphene oxide interlayer electron-phonon coupling on the electro-optical parameters of a ferroelectric liquid crystal

Electro-optical properties of FLC are cell thickness dependent. Interlayer electron-phonon coupling is responsible for the change in the E-O properties. The FLC–GO composite is suitable for use in UV filters.

Comparative Evaluation of Specific Phytochemical Indicatives in Cirivilvādi Kaṣāya Prepared Freshly and at Commercial Scale

Kaṣāya or decoction is an Ayurvedic dosage form, prescribed based on the stage of the disease according to the principles of Ayurveda. This dosage form is traditionally prepared fresh and consumed on the same day but for the sake of convenience; the process of preparation has been modified so that it can be stored with longer shelf life, easy availability and produced in large quantities. There is a need to understand the implications of this modification in terms of chemical changes. This work attempted to check the phytochemical profile of both freshly prepared decoction and commercially available decoction with reference to some analytical parameters like pH, total soluble solids, phenols, alkaloids, potassium and to assess the changes in the thin layer chromatography profiling of the decoction. The results showed that phenols and potassium are found to be two fold higher in freshly prepared decoction, compared to commercially available decoction diluted to dosage in practice (1:4 ratio). However, the total alkaloid content was found to be approximately ten fold higher in commercially available decoction. It was observed that the thin layer chromatography profile of decoctions was extracted into petroleum ether and chloroform was similar and consistent with different batches though the bands in commercially available decoction were slightly more intense compared to freshly prepared decoction. The total soluble solids in commercially available decoction were four times higher than freshly prepared decoction. The study reveals that there are differences in the phytochemical profiles of the freshly prepared decoction and commercially available decoction of the same formulation. However, the significance of these differences can be determined only by further clinical studies. On the other hand, the study lends support to the practice of diluting the commercially available decoction to make it equivalent to freshly prepared decoction.

Identification of a candidate stem cell in human gallbladder

There are currently no reports of identification of stem cells in human gallbladder. The differences between human gallbladder and intrahepatic bile duct (IHBD) cells have also not been explored. The goals of this study were to evaluate if human fetal gallbladder contains a candidate stem cell population and if fetal gallbladder cells are distinct from fetal IHBD cells. We found that EpCAM+CD44+CD13+ cells represent the cell population most enriched for clonal self-renewal from primary gallbladder. Primary EpCAM+CD44+CD13+ cells gave rise to EpCAM+CD44+CD13+ and EpCAM+CD44+CD13- cells in vitro, and gallbladder cells expanded in vitro exhibited short-term engraftment in vivo. Last, we found that CD13, CD227, CD66, CD26 and CD49b were differentially expressed between gallbladder and IHBD cells cultured in vitro indicating clear phenotypic differences between the two cell populations. Microarray analyses of expanded cultures confirmed that both cell types have unique transcriptional profiles with predicted functional differences in lipid, carbohydrate, nucleic acid and drug metabolism. In conclusion, we have isolated a distinct clonogenic population of epithelial cells from primary human fetal gallbladder with stem cell characteristics and found it to be unique compared to IHBD cells.

Restoring systemic GDF11 levels reverses age-related dysfunction in mouse skeletal muscle

Parabiosis experiments indicate that impaired regeneration in aged mice is reversible by exposure to a young circulation, suggesting that young blood contains humoral "rejuvenating" factors that can restore regenerative function. Here, we demonstrate that the circulating protein growth differentiation factor 11 (GDF11) is a rejuvenating factor for skeletal muscle. Supplementation of systemic GDF11 levels, which normally decline with age, by heterochronic parabiosis or systemic delivery of recombinant protein, reversed functional impairments and restored genomic integrity in aged muscle stem cells (satellite cells). Increased GDF11 levels in aged mice also improved muscle structural and functional features and increased strength and endurance exercise capacity. These data indicate that GDF11 systemically regulates muscle aging and may be therapeutically useful for reversing age-related skeletal muscle and stem cell dysfunction.

Posological Considerations of Ocimum sanctum (Tulasi) as per Ayurvedic Science and Pharmaceutical Sciences

A study in 2010 reported that administration of 2 g of O. sanctum leaves for 30 days to laboratory male albino rabbits showed adverse effect on sperm count and male hormones. The dose and duration at which this testing was reported was commented upon as being high. It is learnt that basis this publication a few European regulators have imposed restrictions on usage of O. sanctum. Recognizing the need for evaluation, a review has been made of the posological considerations related to decision on dose of a drug in pharmaceuticals (drug development stages) and in Ayurvedic science as part of history of use and current usage. Specifically, we report the dose range as per documented tradition, marketed products containing O. sanctum as an ingredient and current clinical practice. Greater consultation is suggested before deciding the studies on Ayurvedic herbs. Regulatory action of banning use of O. sanctum needs a review and may need to be replaced with an advisory.

Identification and expansion of a unique stem cell population from adult mouse gallbladder

The identification of resident stem cells in the mouse gallbladder is, to date, unexplored. In addition, the relationship between adult gallbladder stem cells and intrahepatic bile duct (IHBD) cells is not well understood. The aim of this study was to isolate stem cells from an adult mouse gallbladder and determine whether they were unique, compared to IHBD cells. By limiting dilution analyses and index sorts, we found that an EpCAM(+) CD49f(hi) epithelial cell subpopulation from primary gallbladder is enriched in colony-forming cells, compared to EpCAM(+) CD49f(lo) cells. EpCAM(+) CD49f(hi) cells expressed cluster of differentiation (CD)29, CD133, and stem cell antigen-1, but were negative for lineage markers CD31, CD45, and F4/80. Using a novel feeder cell-culture system, we observed long-term (>passage 20) and clonal expansion of the EpCAM(+) CD49f(hi) cells in vitro. In a matrigel differentiation assay, EpCAM(+) CD49f(+) cells expanding in vitro underwent organotypic morphogenesis forming ductular structures and cysts. These structures are similar to, and recapitulate a transport function of, primary gallbladder. EpCAM(+) CD49f(+) cells also engraft into the subcutaneous space of recipient mice. We compared primary gallbladder and IHBD cells by flow cytometry and found phenotypic differences in the expression of CD49f, CD49e, CD81, CD26, CD54, and CD166. In addition, oligonucleotide microarrays showed that the expanded EpCAM(+) CD49f(+) gallbladder cells and IHBD cells exhibit differences related to lipid and drug metabolism. Notable genes that were different are cytochrome P450, glutathione S-transferase, Indian hedgehog, and solute carrier family genes.

CONCLUSION

We have isolated an epithelial cell population from primary mouse gallbladder with stem cell characteristics and found it to be unique, compared to IHBD cells.

1,7,8,9,10,10-Hexachloro-4-(thiophen-2-ylmethyl)-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione

In the title compound, C₁₄H₇Cl₆NO₂S, the six-membered ring of the aza­tricyclo system has a boat conformation whereas the five-membered rings have an envelope conformation. The thio­phene ring and the ring of the succinimide moiety enclose a dihedral angle of 67.2 (1)°. The crystal packing is stabilized by weak inter­molecular C—H⋯O hydrogen bonds.

1,7,8,9,10,10-Hexachloro-4-(2-phenyl-eth-yl)-4-aza-tricyclo-[5.2.1.0]dec-8-ene-3,5-dione

In the title compound, C(17)H(11)Cl(6)NO(2), the six-membered ring of the norbornene moiety adopts a boat conformation whereas the two five-membered rings adopt envelope conformations. The phenyl ring and the ring of the succinimide moiety are almost coplanar [dihedral angle = 7.44 (14)°]. The crystal packing is stabilized by a weak inter-molecular C-H⋯O hydrogen bond.

Rescue of lethal hepatic failure by hepatized lymph nodes in mice

BACKGROUND & AIMS

Hepatocyte transplantation is a potential therapeutic approach for liver disease. However, most patients with chronic hepatic damage have cirrhosis and fibrosis, which limit the potential for cell-based therapy of the liver. The development of an ectopic liver as an additional site of hepatic function represents a new approach for patients with end-stage liver disease. We investigated the development and function of liver tissue in lymph nodes in mice with liver failure.

METHODS

Hepatocytes were isolated from 8- to 12-week-old mice and transplanted by intraperitoneal injection into 8- to 12-week-old fumarylacetoacetate hydrolase mice (Fah(-/-)), a model of the human liver disease tyrosinemia type I. Survival was monitored and the locations and functions of the engrafted liver cells were determined.

RESULTS

Lymph nodes of Fah(-/-) mice were colonized by transplanted hepatocytes; Fah(+) hepatocytes were detected adjacent to the CD45(+) lymphoid cells of the lymphatic system. Ten weeks after transplantation, these mice had substantial improvements in serum levels of transaminases, bilirubin, and amino acids. Homeostatic expansion of donor hepatocytes in lymph nodes rescued the mice from lethal hepatic failure.

CONCLUSIONS

Functional ectopic liver tissue in lymph nodes rescues mice from lethal hepatic disease; lymph nodes therefore might be used as sites for hepatocyte transplantation.

Neuralgic amyotrophy

Neuralgic amyotrophy is an uncommon condition characterised by the acute onset of severe pain in the shoulder and arm, followed by weakness and atrophy of the affected muscles, and sensory loss as the pain subsides. The diversity of its clinical manifestations means that it may present to a variety of different specialties within medicine. This article describes the epidemiology, aetiopathogenesis, clinical features, differential diagnoses, investigations, treatment, course and prognosis of the condition.

Identification of active-site residues of sheep liver serine hydroxymethyltransferase

Chemical modification of amino acid residues with phenylglyoxal, N-ethylmaleimide and diethyl pyrocarbonate indicated that at least one residue each of arginine, cysteine and histidine were essential for the activity of sheep liver serine hydroxymethyltransferase. The second-order rate constants for inactivation were calculated to be 0.016 mM-1 X min-1 for phenylglyoxal, 0.52 mM-1 X min-1 for N-ethylmaleimide and 0.06 mM-1 X min-1 for diethyl pyrocarbonate. Different rates of modification of these residues in the presence and in the absence of substrates and the cofactor pyridoxal 5'-phosphate as well as the spectra of the modified protein suggested that these residues might occur at the active site of the enzyme.

Kinetic mechanism of the interaction of D-cycloserine with serine hydroxymethyltransferase

The kinetic mechanism for the interaction of D-cycloserine with serine hydroxymethyltransferase (EC 2.1.2.1) from sheep liver was established by measuring changes in the activity, absorbance, and circular dichoism (CD) of the enzyme. The irreversible inhibition of the enzyme was characterized by three detectable steps: an initial rapid step followed by two successive steps with rate constants of 5.4 X 10(-3) s-1 and 1.4 X 10(-4) s-1. The first step was distinguished by a rapid disappearance of the enzyme absorbance peak at 425 nm, a decrease in the enzyme activity to 25% of the uninhibited velocity, and a lowering of the CD intensity at 432 nm to about 65% of the original value. The second step of the interaction was accompanied by a complete loss of enzyme activity and a marginal increase in the CD intensity at 432 nm. The final step resulted in the complete loss of the enzyme absorbance at 425 nm and of the CD band at 432 nm. The products of the reaction were identified as (a) apoenzyme by absorbance measurements, CD spectra, and reconstitution with pyridoxal 5'-phosphate and (b) a pyridoxal 5'-phosphate-D-cycloserine Schiff's base complex identified by its fluorescence and absorbance spectra. The Schiff base complex was expelled from the enzyme active site in the final step of the reaction. The proposed mechanism, which is different from those operative in other pyridoxal phosphate dependent enzymes, probably accounts for the selective inhibition of serine hydroxymethyltransferase by the drug in vivo.