Fabrication and Application of Rose Bengal-chitosan Films in Laser Tissue Repair

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges^1,2. These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production³. In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (λ=532 nm, Fluence~110 J/cm², spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 ± 6 kPa, (n=30). The adhesion strength drops to 2 ± 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.     

Metformin (dimethyl-biguanide) induced DNA damage in mammalian cells

Metformin (dimethyl-biguanide) is an insulin-sensitizing agent that lowers fasting plasma-insulin concentration, wherefore it's wide use for patients with a variety of insulin-resistant and prediabetic states, including impaired glucose tolerance. During pregnancy it is a further resource for reducing first-trimester pregnancy loss in women with the polycystic ovary syndrome. We tested metformin genotoxicity in cells of Chinese hamster ovary, CHO-K1 (chromosome aberrations; comet assays) and in mice (micronucleus assays). Concentrations of 114.4 μg/mL and 572 μg/mL were used in in vitro tests, and 95.4 mg/kg, 190.8 mg/kg and 333.9 mg/kg in assaying. Although the in vitro tests revealed no chromosome aberrations in metaphase cells, DNA damage was detected by comet assaying after 24 h of incubation at both concentrations. The frequency of DNA damage was higher at concentrations of 114.4 μg/mL. Furthermore, although mortality was not observed in in vitro tests, the highest dose of metformin suppressed bone marrow cells. However, no statistically significant differences were noted in micronuclei frequencies between treatments. In vitro results indicate that chronic metformin exposure may be potentially genotoxic. Thus, pregnant woman undergoing treatment with metformin should be properly evaluated beforehand, as regards vulnerability to DNA damage.     

Effects of self-selected music on strength, explosiveness, and mood

There has been much investigation into the use of music as an ergogenic aid to facilitate physical performance. However, previous studies have primarily focused on predetermined music and aerobic exercise. The purpose of this study was to investigate the effects of self-selected music (SSM) vs. those of no music (NM) on the mood and performance of the athletes performing bench press and squat jump. Twenty resistance trained collegiate men completed 2 experimental conditions, one while listening to SSM and the other with NM. The subjects reported their profile of mood states (POMS) and rating of perceived exertion (RPE) before and after performing 3 sets to failure of the bench press at 75% 1 repetition maximum (1RM) and 3 reps of the squat jump at 30% 1RM. Statistical analyses revealed no differences in squat jump height or relative ground reaction force, but the takeoff velocity (SSM-2.06 ± 0.17 m·s(-1); NM-1.99 ± 0.18 m·s(-1)), rate of velocity development (SSM-5.92 ± 1.46 m·s(-2); NM-5.63 ± 1.70 m·s(-2)), and rate of force development (SSM-3175.61 ± 1792.37 N·s(-1); NM-2519.12 ± 1470.32 N·s(-1)) were greater with SSM, whereas RPE (SSM-5.71 ± 1.37; NM-6.36 ± 1.61) was greater with NM. Bench press reps to failure and RPE were not different between conditions. The POMS scores of vigor (SSM-20.15 ± 5.58; NM-17.45 ± 5.84), tension (SSM-8.40 ± 3.99; NM-6.07 ± 3.26), and fatigue (SSM-8.65 ± 4.49; NM-7.40 ± 4.38) were greater with SSM. This study demonstrated increased performance during an explosive exercise and an altered mood state when listening to SSM. Therefore, listening to SSM might be beneficial for acute power performance.     

Imaging characteristics, tissue distribution, and spread of a novel oncolytic vaccinia virus carrying the human sodium iodide symporter

Introduction

Oncolytic viruses show promise for treating cancer. However, to assess therapy and potential toxicity, a noninvasive imaging modality is needed. This study aims to determine the in vivo biodistribution, and imaging and timing characteristics of a vaccinia virus, GLV-1h153, encoding the human sodium iodide symporter (hNIS.

Methods

GLV-1h153 was modified from GLV-1h68 to encode the hNIS gene. Timing of cellular uptake of radioiodide ¹³¹I in human pancreatic carcinoma cells PANC-1 was assessed using radiouptake assays. Viral biodistribution was determined in nude mice bearing PANC-1 xenografts, and infection in tumors confirmed histologically and optically via Green Fluorescent Protein (GFP) and bioluminescence. Timing characteristics of enhanced radiouptake in xenografts were assessed via ¹²⁴I-positron emission tomography (PET). Detection of systemic administration of virus was investigated with both ¹²⁴I-PET and 99m-technecium gamma-scintigraphy.

Results

GLV-1h153 successfully facilitated time-dependent intracellular uptake of ¹³¹I in PANC-1 cells with a maximum uptake at 24 hours postinfection (P<0.05). In vivo, biodistribution profiles revealed persistence of virus in tumors 5 weeks postinjection at 10⁹ plaque-forming unit (PFU)/gm tissue, with the virus mainly cleared from all other major organs. Tumor infection by GLV-1h153 was confirmed via optical imaging and histology. GLV-1h153 facilitated imaging virus replication in tumors via PET even at 8 hours post radiotracer injection, with a mean %ID/gm of 3.82±0.46 (P<0.05) 2 days after intratumoral administration of virus, confirmed via tissue radiouptake assays. One week post systemic administration, GLV-1h153-infected tumors were detected via ¹²⁴I-PET and 99m-technecium-scintigraphy.

Conclusion

GLV-1h153 is a promising oncolytic agent against pancreatic cancer with a promising biosafety profile. GLV-1h153 facilitated time-dependent hNIS-specific radiouptake in pancreatic cancer cells, facilitating detection by PET with both intratumoral and systemic administration. Therefore, GLV-1h153 is a promising candidate for the noninvasive imaging of virotherapy and warrants further study into longterm monitoring of virotherapy and potential radiocombination therapies with this treatment and imaging modality.     

Preservation of cGMP-induced relaxation of pulmonary veins of fetal lambs exposed to chronic high altitude hypoxia: role of PKG and Rho kinase

The roles of Rho kinase (ROCK) and cGMP-dependent protein kinase (PKG) in cGMP-mediated relaxation of fetal pulmonary veins exposed to chronic hypoxia (CH) were investigated. Fourth generation pulmonary veins were dissected from near-term fetuses ( approximately 140 days of gestation) delivered from ewes exposed to chronic high altitude hypoxia for approximately 110 days (CH) and from control ewes. After constriction with endothelin-1, 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) caused a similar relaxation of both control and CH vessels. Rp-8-Br-PET-cGMPS (a PKG inhibitor) inhibited whereas Y-27632 (a ROCK inhibitor) augmented relaxation of control veins to 8-Br-cGMP. These effects were significantly diminished in CH veins. PKG protein expression and activity were greater whereas ROCK protein expression and activity were less in CH vessels compared with controls. Phosphorylation of threonine 696 (ROCK substrate) and serine 695 (PKG substrate) of the regulatory myosin phosphatase targeting subunit MYPT1 of myosin light chain (MLC) phosphatase was stimulated to a lesser extent in CH than in control veins by endothelin-1 (ROCK stimulant) and 8-Br-cGMP (PKG stimulant), respectively. The phosphorylation and dephosphorylation of MLC caused by endothelin-1 and 8-Br-cGMP, respectively, were less in CH veins than in controls. These results suggest that CH in utero upregulates PKG activity but attenuates PKG action in fetal pulmonary veins. These effects are offset by the diminished ROCK action on MYPT1 and MLC and thus lead to an unaltered response to cGMP.     

Small Molecule,Non-Peptide p75NTR Ligands Inhibit Aβ-Induced Neurodegeneration and Synaptic Impairment

The p75 neurotrophin receptor (p75^NTR) is expressed by neurons particularly vulnerable in Alzheimer''s disease (AD). We tested the hypothesis that non-peptide, small molecule p75^NTR ligands found to promote survival signaling might prevent Aβ-induced degeneration and synaptic dysfunction. These ligands inhibited Aβ-induced neuritic dystrophy, death of cultured neurons and Aβ-induced death of pyramidal neurons in hippocampal slice cultures. Moreover, ligands inhibited Aβ-induced activation of molecules involved in AD pathology including calpain/cdk5, GSK3β and c-Jun, and tau phosphorylation, and prevented Aβ-induced inactivation of AKT and CREB. Finally, a p75^NTR ligand blocked Aβ-induced hippocampal LTP impairment. These studies support an extensive intersection between p75^NTR signaling and Aβ pathogenic mechanisms, and introduce a class of specific small molecule ligands with the unique ability to block multiple fundamental AD-related signaling pathways, reverse synaptic impairment and inhibit Aβ-induced neuronal dystrophy and death.     

Antinociceptive effect of the C-terminus of murine S100A9 protein on experimental neuropathic pain

The synthetic peptide identical to the C-terminus of murine S100A9 protein (mS100A9p) has antinociceptive effect on different acute inflammatory pain models. In this study, the effect of mS100A9p was investigated on neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve in rats. Hyperalgesia, allodynia, and spontaneous pain were assessed to evaluate nociception. These three signs were detected as early as 2 days after sciatic nerve constriction and lasted for over 14 days after CCI. Rats were treated with different doses of mS100A9p by intraplantar, oral, or intrathecal routes on day 14 after CCI, and nociception was evaluated 1h later. These three routes of administration blocked hyperalgesia, allodynia and spontaneous pain. The duration of the effect of mS100A9p depends on the route used and phenomenon analyzed. Moreover, intraplantar injection of mS100A9p in the contralateral paw inhibited the hyperalgesia on day 14 days after CCI. The results obtained herein demonstrate the antinociceptive effect of the C-terminus of murine S100A9 protein on experimental neuropathic pain, suggesting a potential therapeutic use for it in persistent pain syndromes, assuming that tolerance does not develop to mS100A9p.     

Chronological aging-induced apoptosis in yeast

Saccharomyces cerevisiae is the simplest among the major eukaryotic model organisms for aging and diseases. Longevity in the chronological life span paradigm is measured as the mean and maximum survival period of populations of non-dividing yeast. This paradigm has been used successfully to identify several life-regulatory genes and three evolutionary conserved pro-aging pathways. More recently, Schizosaccharomyces pombe has been shown to age chronologically in a manner that resembles that of S. cerevisiae and that depends on the activity of the homologues of two pro-aging proteins previously identified in the budding yeast. Both yeast show features of apoptotic death during chronological aging. Here, we review some fundamental aspects of the genetics of chronological aging and the overlap between yeast aging and apoptotic processes with particular emphasis on the identification of an aging/death program that favors the dedifferentiation and regrowth of a few better adapted mutants generated within populations of aging S. cerevisiae. We also describe the use of a genome-wide screening technique to gain further insights into the mechanisms of programmed death in populations of chronologically aging S. cerevisiae.