Vascularized composite islet-kidney transplantation in a miniature swine model

Previous work from this laboratory has demonstrated that transplantation of allogeneic thymic tissue as part of a composite vascularized graft is far more successful in terms of both engraftment and long-term survival than transplantation of thymic tissue or cells alone. We have subsequently extended this concept to transplantation of allogeneic islets, comparing survival of islet cell suspensions to that of vascularized composite islet-kidneys (IK), prepared by injection of autologous islets underneath the renal capsule 2-3 months prior to allogeneic transplantation of the composite organ. We have utilized partially inbred miniature swine with defined MHC loci as the experimental large animals for this study, permitting reproducible transplantation across specific MHC barriers. Composite IK have been transplanted successfully across minor and full MHC mismatch barriers, using treatment regimens previously demonstrated to induce long-term tolerance of kidney allografts across these barriers. IK allografts containing ≥5000 islet equivalents (IE)/kg recipient body weight were found capable of reversing surgically induced diabetes, while injection of comparable numbers of purified islets via the portal vein or under the renal capsule did not. Studies are also being directed toward preparation of autologous “thymo-islet-kidneys” (TIK), for potential use as xenografts, in which the thymic component is intended to induce tolerance and the islets to reverse diabetic hyperglycemia. The use of both types of composite organ transplants may eventually be applicable to the treatment of type I diabetic patients suffering from end-stage diabetic nephropathy.     

Isolation and functional characterization of three abiotic stress-inducible (Apx,Dhn and Hsc70) promoters from pearl millet (Pennisetum glaucum L.)

Molecular Biology Reports - Pearl millet is a C4 cereal crop that grows in arid and semi-arid climatic conditions with the remarkable abiotic stress tolerance. It contributed to the understanding...     

Metal–Organic Framework: A Novel Material for Triboelectric Nanogenerator–Based Self‐Powered Sensors and Systems

The triboelectric nanogenerator (TENG) offers a simple and cost‐effective method to harness waste energy and works on the principle of contact electrification and electrostatic induction. The performance and application of TENG depend to a great extent on the material used for fabrication. The most widely used materials include polymers and a few metals, well‐arranged in the triboelectric series so as to promote electrification upon contact. New triboelectric materials are important for extending the applications and specificity of the TENG. A TENG based on a metal–organic framework (MOF) of the zeolitic imidazole family is reported here. The zeolitic imidazole framework‐8 (ZIF‐8) and Kapton are used as the active materials for MOF–TENG fabrication. Surface potential, structural, morphological and electrical measurements reveals detailed characteristics of ZIF‐8, confirming the MOF as a potential candidate for TENG applications. The MOF–TENG generates a sustainable output of 164 V and 7 µA in vertical contact–separation mode. Finally, a self‐powered UV counterfeit system and a tetracycline sensor are successfully developed and demonstrated with the MOF–TENG. The sensor is highly selective and reusable simply by washing.     

Antioxidant enzyme changes in neem,pigeonpea and mulberry leaves in two stages of maturity

Differential expression of antioxidant enzymes in various growth and differentiation stages has been documented in several plant species. We studied here, the difference in the levels of protein content and antioxidant enzymes activity at two stages of maturity, named young and mature in neem (Azadirachta indica A. Juss), pigeonpea (Cajanus cajan (L.) mill sp) and mulberry (Morus Alba L.) leaves. The results showed that detached neem and pigeonpea mature leaves possessed higher activities of catalase (CAT) and peroxidase (POD) and lower activities of polyphenol oxidase (PPO) and ascorbate peroxidase (APX) as compared with young leaves. However, glutathione reductase (GR) showed higher activity in mature leaves of neem, whereas no change in its activity was observed in pigeonpea. On the other hand, antioxidant enzymes in mulberry showed either positive (PPO) or negative (POD, GR, APX) correlation with the progression of leaf maturity. Apparently the trend of changes in antioxidant enzymes activity during leaf development is species-specific: their activity higher at mature stage in some plants and lower in others.     

X-ray crystal structures of rabbit N-acetylglucosaminyltransferase I (GnT I) in complex with donor substrate analogues

The Golgi-resident glycosyltransferase, UDP-N-acetyl-d-glucosamine:alpha-3-d-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT I), initiates the conversion of high-mannose oligosaccharides to complex and hybrid structures in the biosynthesis of N-linked glycans. Reported here are the X-ray crystal structures of GnT I in complex with UDP-CH2-GlcNAc (a non-hydrolyzable C-glycosidic phosphonate), UDP-2-deoxy-2-fluoro-glucose, UDP-glucose and UDP. Collectively, these structures provide evidence for the importance of the GlcNAc moiety and its N-acetyl group in donor substrate binding, as well as insight into the role played by the flexible 318-330 loop in substrate binding and product release. In addition, the UDP-CH2-GlcNAc complex reveals a well-defined glycerol molecule poised for nucleophilic attack on the C1 atom of the donor substrate analogue. The position and orientation of this glycerol molecule have allowed us to model the binding of the Manalpha1,3Manbeta1 moiety of the acceptor substrate and, based on the model, to suggest a rationalization for the main determinants of GnT I acceptor specificity.     

Modeling of Neuropeptide Receptors Y1, Y4, Y5, and Docking Studies with Neuropeptide Antagonist Analogues: Implications for Selectivity

Abstract Neuropeptide Y (NPY), receptors belong to the G-protein coupled receptor superfamily. NPY mediates several physiological responses, such as blood pressure, food intake, sedation. These actions of NPY are mediated by six receptor subtypes denoted as Y(1)-Y(5) and y(6). Modeling of receptor subtypes and binding site identification is an important step in developing new therapeutic agents. We have attempted to model the three NPY receptor types, Y1, Y4, and Y5 using homology modeling and threading methods. The models are consistent with previously reported experimental evidence. To understand the interaction and selectivity of NPY analogues with different neuropeptide receptors, docking studies of two neuropeptide analogues (BVD10 and BVD15) with receptors Y1 and Y4 were carried out. Results of the docking studies indicated that the interaction of ligands BVD10 and BVD15 with Y1 and Y4 receptors are different. These results were evaluated for selectivity of peptide analogues BVD10 and BVD15 towards the receptors.     

Structural and ICAM-1-Docking Properties of a Cyclic Peptide from the I-domain of LFA-1: An inhibitor of ICAM-1/LFA-1-mediated T-cell adhesion

Abstract

The purpose of this work was to study the conformation of cyclic peptide 1, cyclo(1,12)- Pen1-Ile2-Thr3-Asp4-Gly5-Glu6-Ala7-Thr8-Asp9-Ser10-Gly11-Cys12-OH, derived from the I-domain of the LFA-1 α-subunit. We found that cyclic peptide 1 can bind to the D1- domain of ICAM-1 and inhibit ICAM-1/LFA-1-mediated homotypic and heterotypic T-cell adhesion. To understand the bioactive conformation and binding requirements for cyclic peptide 1, its solution structure was studied using NMR, CD, and molecular dynamics simulations. Furthermore, possible binding properties between the cyclic peptide and the D1- domain of ICAM-1 were evaluated using docking experiments. This cyclic peptide has a stable βII'-turn at Asp4-Gly5-Glu6-Ala7 and a βI-turn at Pen1-Ile2-Thr3-Asp4; a less stable βV-turn is found at the C-terminal region. The β-turn at Asp4-Gly5-Glu6-Ala7 was also found in the X-ray structure of the I-domain of LFA-1. Our CD studies showed that the peptide binds to calcium/magnesium and forms a 1:1 (peptide:calcium/magnesium) complex with low cation concentrations and multiple types of complexes with higher cation concentrations. Binding to divalent cations causes a conformational change in peptide 1; this is consistent with our previous study that binding of peptide 1 to ICAM-1 was influenced by divalent cations. Docking studies show the interaction between cyclic peptide 1 and the D1- domain of ICAM-1; it indicates that the Ile2-Thr3-Asp4-Gly4-Glu6-Ala7-Thr8 sequence interacts with the F and C strands of the D1-domain. Finally, these studies will help us design a new generation of selective peptides that may bind better to the D1-domain of ICAM-1.     

High-resolution genotyping of Pseudomonas aeruginosa strains linked to acute post cataract surgery endophthalmitis outbreaks in India

Background

The number of Salmonella strains with reduced susceptibility to fluoroquinolones has increased during recent years in many countries, threatening the value of this antimicrobial group in the treatment of severe salmonella infections.

Methods

We analyzed the in vitro activities of ciprofloxacin and 10 additional fluoroquinolones against 816 Salmonella strains collected from Finnish patients between 1995 and 2003. Special attention was focused on the efficacy of newer fluoroquinolones against the Salmonella strains with reduced ciprofloxacin susceptibility.

Results

The isolates represented 119 different serotypes. Of all 816 Salmonella strains, 3 (0.4%) were resistant to ciprofloxacin (MIC ≥ 4 μg/ml), 232 (28.4%) showed reduced susceptibility to ciprofloxacin (MIC ≥ 0.125 – 2 μg/ml), and 581 (71.2%) were ciprofloxacin-susceptible. The MIC₅₀ and MIC₉₀ values of ciprofloxacin for these strains were 0.032 and 0.25 μg/ml, respectively, being lower than those of the other fluoroquinolone compounds presently on market in Finland (ofloxacin, norfloxacin, levofloxacin, and moxifloxacin). For two newer quinolones, clinafloxacin and sitafloxacin, the MIC₅₀ and MIC₉₀ values were lowest, both 0.016 and 0.064 μg/ml, respectively. Moreover, clinafloxacin and sitafloxacin exhibited the lowest MIC₅₀ and MIC₉₀ values, 0.064 and 0.125 μg/ml, against the 235 Salmonella strains with reduced susceptibility and strains fully resistant to ciprofloxacin.

Conclusion

Among the registered fluoroquinolones in Finland, ciprofloxacin still appears to be the most effective drug for the treatment salmonella infections. Among the newer preparations, both clinafloxacin and sitafloxacin are promising based on in vitro studies, especially for strains showing reduced ciprofloxacin susceptibility. Their efficacy, however, has not been demonstrated in clinical investigations.     

Optimising surgical management of elderly cancer patients

BACKGROUND: Elderly population is on rise. It is an ethical dilemma how aggressive one should be when it comes to treat cancer in elderly. Presumed fear of increased postoperative morbidity and mortality has resulted in delivery of sub-optimal cancer surgery. METHODS: In this review article we visit physiology of the aged, tools available to assess surgical risks in oncogeriatric patients, and current practice in the management of common cancers encountered in surgical oncology, with the view of increasing awareness on optimising surgical management of senior patients with cancer. A pubmed search for cancer, surgery, elderly, was carried out. RESULTS: Cancer is on rise with increasing age predominantly affecting breast, gastrointestinal tract and lung. Increasingly more surgeons are offering surgery to elderly cancer patient but selection bias is prevalent. Available data reflect short and long-term outcome of cancer surgery in elderly is not greatly different to that of younger patient. Declining physiological reserve along with inability to respond adequately to physiological stress are salient age related changes. Comprehensive Geriatric Assessment (CGA) is not tested in surgical patient. There is need for a tool to define individualised operative risk. Preoperative assessment of cancer in elderly is designed to offer this information based on functional status of an individual utilising currently available tools of risk assessment. CONCLUSION: All elderly cancer patients should be offered optimal treatment depending on their functional status not on chronological age. Oncogeriatric patient would benefit from dedicated multidisciplinary approach. Recruitment of elderly cancer patients to more clinical trials is needed to enhance our knowledge and to offer optimum treatment to this unique subgroup.