Toxicity and biomedical imaging of layered nanohybrids in the mouse

Layered nanohybrids (LNH) are a promising nonviral system allowing controlled drug and DNA delivery. In order to test the toxicity of LNH consisting of a magnesium/aluminum core, mice were subjected to subcutaneous, intraperitoneal, and intravenous injections of these nanoparticles at three doses. Intravenous injections resulted in 8% (1 out of 12) lethality at doses 100 micro l and 200 micro l of 6.96 x 10(- 4) M solution, while all mice survived after LNH administration by any other routes. Histopathological alterations were limited to mild localized inflammatory lesions in the lungs and the dermis after intravenous and subcutaneous administration, respectively. LNH labeled with Lucifer Yellow were readily detectable in both locations by fluorescent microscopy. To test their potential for intravital imaging, LNH-Lucifer Yellow were injected into the ovarian bursa and successfully visualized by multiphoton microscopy within the ovarian surface epithelial cells. In similar experiments, the ovary and the ovarian bursa were readily detectable by magnetic resonance imaging after administration of modified LNH, where aluminum was substituted for gadolinium. Taken together, these results demonstrate minimal in vivo toxicity of LNH and illuminate their potential as multifunctional nanoscale particles suitable for combination of intravital biomedical imaging with controlled drug release.     

Role of Chemistry and Crystal Structure on the Electronic Defect States in Cs-Based Halide Perovskites

The electronic structure of a series perovskites ABX₃ (A = Cs; B = Ca, Sr, and Ba; X = F, Cl, Br, and I) in the presence and absence of antisite defect X_B were systematically investigated based on density-functional-theory calculations. Both cubic and orthorhombic perovskites were considered. It was observed that for certain perovskite compositions and crystal structure, presence of antisite point defect leads to the formation of electronic defect state(s) within the band gap. We showed that both the type of electronic defect states and their individual energy level location within the bandgap can be predicted based on easily available intrinsic properties of the constituent elements, such as the bond-dissociation energy of the B–X and X–X bond, the X–X covalent bond length, and the atomic size of halide (X) as well as structural characteristic such as B–X–B bond angle. Overall, this work provides a science-based generic principle to design the electronic states within the band structure in Cs-based perovskites in presence of point defects such as antisite defect.     

Antibacterial potential of Ni-doped zinc oxide nanostructure: comparatively more effective against Gram-negative bacteria including multi-drug resistant strains

Infections by multidrug-resistant (MDR) bacteria are one of the most threatening concerns for public health. For this purpose, nanomaterials have emerged with great potential for antibacterial activity. In this paper, we report the synthesis of new Ni²⁺-doped zinc oxide (Ni-ZnO or NZO) nanostructures as targeted antibacterial agents for Gram-negative bacteria. A one-pot low-temperature solution process was used with varying compositions containing 2 or 5% Ni²⁺ relative to Zn²⁺, resulting in 2NZO or 5NZO, respectively. X-ray diffractometry, transmission electron microscopy, and X-ray photoelectron spectroscopy were used for material characterization. Further, the antibacterial activity against both Gram-negative [Escherichia coli (E. coli) and Acinetobacter baumannii (A. baumannii) strains including standard, MDR, and clinical isolates associated with mcr-1 gene] and Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) bacteria were evaluated through analysis of zone of inhibition, minimum inhibitory concentration (MIC), and scanning electron microscopy images. Among the prepared nanostructures, the 5NZO sample showed excellent antibacterial activity against MDR strains of A. baumannii and E. coli. In addition, samples of NZO generated approximately 7 to 16 times more reactive oxygen species (ROS) in E. coli compared to ZnO. Our synthesized nanomaterials have the potential to fight MDR and colistin-resistant Gram-negative bacteria.

Synthesis of Ni²⁺-doped ZnO nanoparticles and their antibacterial activity.     

Melatonin synergizes with low doses of L‐DOPA to improve dendritic spine density in the mouse striatum in experimental Parkinsonism

The dopamine precursor, L‐3,4‐dihydroxyphenylalanine (L‐DOPA), is the preferred drug for Parkinson's disease, but long‐term treatment results in the drug‐induced dyskinesias and other side effects. This study was undertaken to examine whether melatonin could potentiate low dose L‐DOPA effects in 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐induced experimental parkinsonism. Mice were treated with the parkinsonian neurotoxin, MPTP, and different doses of melatonin and low doses of L‐DOPA. Behavior, striatal histology, and dopamine metabolism were evaluated on the 7th day. MPTP‐induced striatal dopamine loss was not modified by melatonin administration (10–30 mg/kg; i.p. at 10‐hr intervals, 6 times; or at 2‐hr intervals, by day). However, low doses of L‐DOPA (5 mg/kg, by oral gavage) administered alone or along with melatonin (10 mg/kg, i.p.) twice everyday for 2 days, 10 hr apart, after two doses of MPTP significantly attenuated striatal dopamine loss and provided improvements in both catalepsy and akinesia. Additionally, Golgi‐impregnated striatal sections showed preservation of the medium spiny neurons, which have been damaged in MPTP‐treated mouse. The results demonstrated that melatonin, but not L‐DOPA, restored spine density and spine morphology of medium spiny neurons in the striatum and suggest that melatonin could be an ideal adjuvant to L‐DOPA therapy in Parkinson's disease, and by the use of this neurohormone, it is possible to bring down the therapeutic doses of L‐DOPA.     

Evaluation of direct agglutination test (DAT) and ELISA for serodiagnosis of visceral leishmaniasis in India

The direct agglutination test (DAT) and the enzyme-linked immunosorbent assay (ELISA) were used for serodiagnosis of parasitologically confirmed Indian visceral leishmaniasis (VL) cases. All the sera of VL cases were positive by both the methods. DAT titres of VL cases were greater than or equal to 1:3,200, and ELISA values were greater than or equal to 0.55 1:400 dilution. In the control group, sera of widely prevalent diseases of India, such as leprosy, tuberculosis, malaria, and liver cirrhosis, were included. Both tests could discriminate between VL and other patients of the control group. The sera of post-kala-azar dermal leishmaniasis (PKDL) patients gave OD values of greater than 0:55 and had DAT titres of 1:1,600. Both tests are sensitive and specific for the diagnosis of VL cases. DAT, being simpler and more economical, will be suitable for diagnosis and epidemiological studies for VL under rural conditions of India.     

Laparoscopic Cholecystectomy in a Patient with Situs Inversus

Laparoscopic cholecystectomy is one of the most common laparoscopic surgical procedures in the world today and has become the standard procedure for the treatment of gallstone disease. Symptomatic cholelithiasis in a patient with situs inversus can give rise to a diagnostic dilemma and calls for modification of the operative approach. We report one such case outlining how the diagnosis was made and describing the pitfalls encountered during surgery and how they were overcome.     

Silk fibroin scaffolds with muscle‐like elasticity support in vitro differentiation of human skeletal muscle cells

Human adult skeletal muscle has a limited ability to regenerate after injury and therapeutic options for volumetric muscle loss are few. Technologies to enhance regeneration of tissues generally rely upon bioscaffolds to mimic aspects of the tissue extracellular matrix (ECM). In the present study, silk fibroins from four Lepidoptera (silkworm) species engineered into three‐dimensional scaffolds were examined for their ability to support the differentiation of primary human skeletal muscle myoblasts. Human skeletal muscle myoblasts (HSMMs) adhered, spread and deposited extensive ECM on all the scaffolds, but immunofluorescence and quantitative polymerase chain reaction analysis of gene expression revealed that myotube formation occurred differently on the various scaffolds. Bombyx mori fibroin scaffolds supported formation of long, well‐aligned myotubes, whereas on Antheraea mylitta fibroin scaffolds the myotubes were thicker and shorter. Myotubes were oriented in two perpendicular layers on Antheraea assamensis scaffolds, and scaffolds of Philosamia/Samia ricini (S. ricini) fibroin poorly supported myotube formation. These differences were not caused by fibroin composition per se, as HSMMs adhered to, proliferated on and formed striated myotubes on all four fibroins presented as two‐dimensional fibroin films. The Young's modulus of A. mylitta and B. mori scaffolds mimicked that of normal skeletal muscle, but A. assamensis and S. ricini scaffolds were more flexible. The present study demonstrates that although myoblasts deposit matrix onto fibroin scaffolds and create a permissive environment for cell proliferation, a scaffold elasticity resembling that of normal muscle is required for optimal myotube length, alignment, and maturation. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd. StartCopTextStartCopText© 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.