The utilization of an ocular wound chamber on corneal epithelial wounds

Purpose Currently available ocular moisture chambers are not adequate to manage the treatment of periocular burns, corneal injuries, and infection. The purpose of these studies was to demonstrate that a flexible, semi-transparent ocular wound chamber device adapted from technology currently used on dermal wounds is safe for use on corneal epithelial injuries. Materials and methods A depilatory cream (Nair™, 30 seconds) was utilized to remove the excess hair surrounding the left eyes of anesthetized Institute Armand Frappier (IAF) hairless, female guinea pigs (Crl:HA-Hrhr). A 4 mm corneal epithelium defect was created using a corneal rust ring remover (Algerbrush®II). Epithelial defects were either left untreated or the eyes were fitted with an ocular wound chamber and 0.5 mL of hydroxypropyl methylcellulose (HPMC) gel (GenTeal®) or HPMC liquid (GenTeal®) was injected into each chamber (N=5 per group). At 0, 24, 48, and 72 hours fluorescein and optical coherence tomography imaging was collected and the intraocular pressure (IOP) was measured. H&E staining was performed on corneal and eyelid skin samples and evaluated by a veterinary pathologist. Results: Corneal epithelial wounds demonstrated 100% closure rates when left untreated or treated with an ocular wound chamber containing HPMC gel at 72 hours while wounds treated with an ocular wound chamber containing HPMC liquid were 98% healed. No significant differences were found in corneal thickness and wound healing, IOP, or eyelid skin pathology in any treatment group when compared to controls. Conclusions: This study indicates that adapted wound chamber technology can be safely used on sterile, corneal epithelial wounds without adverse effects on periocular or ocular tissue when filled with a liquid or gel

Regulation of ROS Production and Vascular Function by Carbon Monoxide

Carbon monoxide (CO) is a gaseous molecule produced from heme by heme oxygenase (HO). CO interacts with reduced iron of heme-containing proteins, leading to its involvement in various cellular events via its production of mitochondrial reactive oxygen species (ROS). CO-mediated ROS production initiates intracellular signal events, which regulate the expression of adaptive genes implicated in oxidative stress and functions as signaling molecule for promoting vascular functions, including angiogenesis and mitochondrial biogenesis. Therefore, CO generated either by exogenous delivery or by HO activity can be fundamentally involved in regulating mitochondria-mediated redox cascades for adaptive gene expression and improving blood circulation (i.e., O2 delivery) via neovascularization, leading to the regulation of mitochondrial energy metabolism. This paper will highlight the biological effects of CO on ROS generation and cellular redox changes involved in mitochondrial metabolism and angiogenesis. Moreover, cellular mechanisms by which CO is exploited for disease prevention and therapeutic applications will also be discussed

Repeat low-level blast exposure increases transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1) expression in the trigeminal ganglion.

Blast-associated sensory and cognitive trauma sustained by military service members is an area of extensively studied research. Recent studies in our laboratory have revealed that low-level blast exposure increased expression of transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1), proteins well characterized for their role in mediating pain transmission, in the cornea. Determining the functional consequences of these alterations in protein expression is critical to understanding blast-related sensory trauma. Thus, the purpose of this study was to examine TRPV1 and ET-1 expression in ocular associated sensory tissues following primary and tertiary blast. A rodent model of blast injury was used in which anesthetized animals, unrestrained or restrained, received a single or repeat blast (73.8 ± 5.5 kPa) from a compressed air shock tube once or daily for five consecutive days, respectively. Behavioral and functional analyses were conducted to assess blast effects on nocifensive behavior and TRPV1 activity. Immunohistochemistry and Western Blot were also performed with trigeminal ganglia (TG) to determine TRPV1, ET-1 and glial fibrillary associated protein (GFAP) expression following blast. Increased TRPV1, ET-1 and GFAP were detected in the TG of animals exposed to repeat blast. Increased nocifensive responses were also observed in animals exposed to repeat, tertiary blast as compared to single blast and control. Moreover, decreased TRPV1 desensitization was observed in TG neurons exposed to repeat blast. Repeat, tertiary blast resulted in increased TRPV1, ET-1 and GFAP expression in the TG, enhanced nociception and decreased TRPV1 desensitization

Comparison of Piperacillin and Tazobactam Pharmacokinetics in Critically Ill Patients with Trauma or with Burn

Critical illness caused by burn and sepsis is associated with pathophysiologic changes that may result in the alteration of pharmacokinetics (PK) of antibiotics. However, it is unclear if one mechanism of critical illness alters PK more significantly than another. We developed a population PK model for piperacillin and tazobactam (pip-tazo) using data from 19 critically ill patients (14 non-burn trauma and 5 burn) treated in the Military Health System. A two-compartment model best described pip-tazo data. There were no significant differences found in the volume of distribution or clearance of pip-tazo in burn and non-burn patients. Although exploratory in nature, our data suggest that after accounting for creatinine clearance (CrCl), doses would not need to be increased for burn patients compared to trauma patients on consideration of PK alone. However, there is a high reported incidence of augmented renal clearance (ARC) in burn patients and pharmacodynamic (PD) considerations may lead clinicians to choose higher doses. For critically ill patients with normal kidney function, continuous infusions of 13.5–18 g pip-tazo per day are preferable. If ARC is suspected or the most stringent PD targets are desired, then continuous infusions of 31.5 g pip-tazo or higher may be required. This approach may be reasonable provided that therapeutic drug monitoring is enacted to ensure pip-tazo levels are not supra-therapeutic

Repeat, tertiary blast exposure results in enhanced nocifensive behavior.

<p>A dilute concentration of CAP (0.02%) was applied directly to the eye of unrestrained and restrained animals exposed to primary or tertiary low-level single (A) or repeat (B) blast. Eye wipe (nocifensive) responses were recorded for two minutes following application of CAP. Responses were counted as the amount of the time animal spent flinching and wiping the affected eye with either the paw or hind leg. Behavioral assessments were conducted at the indicated time points. Data are representative of 5–6 animals per treatment group. NS, not significant, **p<0.01and ***p<0.001, Repeated Measures ANOVA with Tukey post-hoc test.</p

Increased CGRP and SP expression in TG sensory neurons exposed to repeat, tertiary blast.

<p>Immunofluorescence analysis was performed on frozen TG sections harvested from control and repeat, tertiary (unrestrained) blast exposed animals. Tissues were subjected to staining with anti-TRPV1 (1:250), anti-CGRP (A) (1:250) and anti-SP (C) (1:250) antibodies and probed with the appropriate Alexa Fluor 568 and 488 secondary antibodies. (B, D) Quantification of CGRP- and SP-positive cells as percent of control animals, respectively. Paired t-test, **p<0.01.</p

Repeat blast exposure results in increased TRPV1 and ET-A co- expression.

<p>Western blot and immunofluorescence analysis was performed on TGs harvested from animals that were exposed to either a single or repeat low-level primary or tertiary low-level blast. (A, B) TGs were homogenized and whole cell lysates (50 μg) were assessed for ET-A protein expression. (C) Quantification of ET-A expression in unrestrained and restrained animals following exposure to a single or repeat blast. (D) Immunofluorescence staining was completed on frozen sections of TGs subjected to repeat, tertiary blast. Tissues were subjected to staining with anti-TRPV1 (1:250) and anti-ET-A (1:250) antibodies and probed with Alexa Fluor 568 and 488 secondary antibodies, respectively. Representative images of an n = 4 for both control and repeat blast animals. NS, not significant, *p<0.05 and **p<0.01, one-way ANOVA with Tukey post-hoc test.</p

Decreased TRPV1 desensitization in TG sensory neurons exposed to tertiary low-level blast.

<p>TG were harvested from control animals and unrestrained animals exposed to a single or repeat, tertiary blast. Cumulative traces (A, B) and quantified responses (C) following initial and subsequent capsaicin (CAP) application, CAP₁ and CAP₂, respectively in KCl-sensitive TRPV1-expressing TG neurons. Shaded, yellow vertical bars denote application of CAP (50nM). (D) Quantified receptor desensitization of the indicated animal groups. NS, not significant, *p<0.05 and **p<0.01, two-way ANOVA with Bonferroni post-hoc test, n = 44–77 neurons/ group.</p