ROS-Mediated Fragmentation Alters the Effects of Hyaluronan on Corneal Epithelial Wound Healing.

A buildup of reactive oxygen species (ROS) occurs in virtually all pathological conditions. Hyaluronan (HA) is a major extracellular matrix component and is susceptible to oxidation by reactive oxygen species (ROS), yet the precise chemical structures of oxidized HA products (oxHA) and their physiological properties remain largely unknown. This study characterized the molecular weight (MW), structures, and physiological properties of oxHA. For this, high-molecular-weight HA (HMWHA) was oxidized using increasing molar ratios of hydrogen peroxide (H2O2) or hypochlorous acid (HOCl). ROS lead to the fragmentation of HA, with the oxHA products produced by HOCl exhibiting an altered chemical structure while those produced by H2O2 do not. HMWHA promotes the viability of human corneal epithelial cells (hTCEpi), while low MWHA (LMWHA), ultra-LMWHA (ULMWHA), and most forms of oxHA do not. HMWHA and LMWHA promote hTCEpi proliferation, while ULMWHA and all forms of oxHA do not. LMWHA and some forms of oxHA promote hTCEpi migration, while HMWHA does not. Finally, all native forms of HA and oxHA produced by HOCl promote in vivo corneal wound healing, while oxHA produced by H2O2 does not. Taken together, our results show that HA fragmentation by ROS can alter the physiological activity of HA by altering its MW and structure.

Characterization of the Molecular Weight of Hyaluronan in Eye Products Using a Novel Method of Size Exclusion High-Pressure Liquid Chromatography.

Purpose: Hyaluronan (HA) exists in two forms, high molecular weight HA (HMWHA) and low molecular weight HA (LMWHA), which have distinct physiological functions. Therefore it is imperative to know the form of HA within pharmaceutical products, including eye products. This study developed an accurate, sensitive, and quantitative method to characterize the form of HA in eye products. Thereafter, the effects of the HA-containing eye products on corneal wound healing were investigated. Methods: The MW distributions and concentrations of HA in over the counter eye products were determined by size exclusion chromatography (SEC) high-pressure liquid chromatography (HPLC). The effects of the eye products containing HA on corneal wound healing were characterized both in vitro and in vivo using the scratch assay and the debridement wound model, respectively. Results: The concentrations and MWs of HA were successfully determined within a range of 0.014 to 0.25 mg/mL using SEC HPLC. The concentrations of HA in the ophthalmic products varied from 0.14 to 4.0 mg/mL and the MWs varied from ∼100 kDa to >2500 kDa. All but one HA-containing eye product had an inhibitory effect on corneal wound healing, whereas pure HA promoted corneal wound healing. Conclusions: A novel SEC-HPLC method was developed for quantifying and characterizing the MW of HA in eye products. Although HA promoted corneal wound healing, HA-containing eye products inhibited corneal wound healing, likely caused by preservatives. Translational Relevance: SEC-HPLC could be implemented as a routine method for determining the form of HA in commercially available ophthalmic products.

Metabolic acidosis due to ingestion of lanthanum sulfates and chlorides in cetyl alcohol solution pool cleaner.

Cetyl Alcohol is a rare cause of acidosis if ingested in large quantities. Hyponatremia with overlapping anion gap and osmolal gap-positive metabolic acidosis may appear to have iso-osmolar serum. This is a case of an unusual toxic exposure.

A Case of Novel Coronavirus Disease 19 in a Chronic Hemodialysis Patient Presenting with Gastroenteritis and Developing Severe Pulmonary Disease.

Novel coronavirus disease 2019 (COVID-19) is a highly infectious, rapidly spreading viral disease with an alarming case fatality rate up to 5%. The risk factors for severe presentations are concentrated in patients with chronic kidney disease, particularly patients with end-stage renal disease (ESRD) who are dialysis dependent. We report the first US case of a 56-year-old nondiabetic male with ESRD secondary to IgA nephropathy undergoing thrice-weekly maintenance hemodialysis for 3 years, who developed COVID-19 infection. He has hypertension controlled with angiotensin receptor blocker losartan 100 mg/day and coronary artery disease status-post stent placement. During the first 5 days of his febrile disease, he presented to an urgent care, 3 emergency rooms, 1 cardiology clinic, and 2 dialysis centers in California and Utah. During this interval, he reported nausea, vomiting, diarrhea, and low-grade fevers but was not suspected of COVID-19 infection until he developed respiratory symptoms and was admitted to the hospital. Imaging studies upon admission were consistent with bilateral interstitial pneumonia. He was placed in droplet-eye precautions while awaiting COVID-19 test results. Within the first 24 h, he deteriorated quickly and developed acute respiratory distress syndrome (ARDS), requiring intubation and increasing respiratory support. Losartan was withheld due to hypotension and septic shock. COVID-19 was reported positive on hospital day 3. He remained in critical condition being treated with hydroxychloroquine and tocilizumab in addition to the standard medical management for septic shock and ARDS. Our case is unique in its atypical initial presentation and highlights the importance of early testing.

Blocking pro-inflammatory platelet-activating factor receptors and activating cell survival pathways: A novel therapeutic strategy in experimental ischemic stroke.

OBJECTIVE: Acute ischemic stroke triggers complex neurovascular, neuroinflammatory, and synaptic alterations. This study explores whether blocking pro-inflammatory platelet-activating factor receptor (PAF-R) plus selected docosanoids after middle cerebral artery occlusion (MCAo) would lead to neurological recovery. The following small molecules were investigated: (a) LAU-0901, a PAF-R antagonist that blocks pro-inflammatory signaling; and (b) derivatives of docosahexaenoic acid (DHA), neuroprotectin D1 (NPD1), and aspirin-triggered NPD1 (AT-NPD1), which activates cell survival pathways and are exert potent anti-inflammatory activity in the brain. MATERIALS AND METHODS: Sprague-Dawley rats received 2 h MCAo and LAU-0901 (30 or 60 mg/kg, 2 h after stroke), NPD1, and AT-NPD1 (333 µg/kg), DHA (5 mg/kg), and their combination were administered intravenous at 3 h after stroke. Behavior testing and ex vivo magnetic resonance imaging were conducted on day 3 or 14 to assess lesion characteristics and lipidomic analysis on day 1. Series 1 (LAU-0901 + NPD1, 14d), Series 2 (LAU-0901 + AT-NPD1, 3d), and Series 3 (LAU-0901 + DHA, 1d). RESULTS: All combinatory groups improved behavior compared to NPD1, AT-NPD1, or DHA treatments alone. Total lesion volumes were reduced with LAU-0901 + NPD1 by 62% and LAU-0901 + AT-NPD1 by 90% treatments versus vehicle groups. LAU-0901 and LAU-0901 + DHA increased the production of vasoactive lipid mediators (prostaglandins: PGE2, PGF2- α, 6-keto-PGF1- α, and PGD2) as well an inflammatory regulating mediator hydroxyoctadecadienoic acid. In contrast, LAU-0901 and LAU-0901 + DHA decreased the production of 12-hydroxyeicosatetraenoic acid, a pro-inflammatory mediator. CONCLUSION: Combination therapy with LAU-0901 and selected docosanoids is more effective than the single therapy, affording synergistic neuroprotection, with restored pro-homeostatic lipid mediators and improved neurological recovery. Altogether, our findings support the combinatory therapy as the basis for future therapeutics for ischemic stroke.

Deaths in Unlicensed Alcohol Rehabilitation Facilities.

Non-English-speaking people do not always seek medical care through established institutions. This paper reports a series of deaths in unlicensed alcohol rehabilitation facilities serving Spanish-speaking men. These facilities are informal groups of alcohol abusing men who live together. New members receive various treatments, including administration of ethanol or isopropanol, restraint, and seclusion. We reviewed 42 deaths in unlicensed alcohol rehabilitation facilities in Los Angeles County during the years 2003-2014. Data gathered included age, length of time spent in the facility, blood alcohol and drugs at autopsy, and cause and manner of death. Causes of death included acute alcohol poisoning, alcohol withdrawal, and a variety of other causes. Three cases were considered homicides from restraint asphyxia. The Department of Medical Examiner-Coroner has worked with the police, district attorney, and State Department of Health Services to try to prevent additional deaths in unlicensed alcohol rehabilitation facilities. Nevertheless, prevention has been difficult.

Fatalities of the 2008 Los Angeles train crash: autopsy findings.

INTRODUCTION: Train crashes represent a devastating multicasualty event. The purpose of this study was to analyze the injury severity, specific organ injuries, and cause of death in the fatalities of the 2008 Chatsworth, Los Angeles train crash. METHODS: This is a review of the medical examiner records of the 25 fatalities in the train crash. The Injury Severity (ISS) Score, body area with severe injuries (Abbreviated Injury Scale [AIS] > or = 4), specific organ injuries, and causes of death were recorded. The immediate cause of death was determined to be the most severe or most rapidly fatal injury in the opinion of the reviewers. RESULTS: A total of 25 fatalities occurred, including 24 victims who were pronounced dead at the accident scene and one who died 4 days later in the hospital. One victim did not undergo full autopsy. All of the decedents were located in the locomotive or in the passenger car immediately behind the locomotive. Overall, 15/24 decedents (63 percent) sustained unsurvivable injuries to at least one body region rendering an ISS of 75. The chest was the most severely injured body area (AIS > or = 4; 18/24, 75 percent), followed by the head (13/24, 54 percent), the extremities (11/24, 46 percent), and the abdomen (7/24, 29 percent). Spinal fractures were recorded in 17/24 (71 percent), and the cervical spine was the most commonly injured site. Thoracic aortic rupture was found in eight cases (33 percent) and cardiac ruptures in five cases (21 percent). CONCLUSIONS: The Metrolink train crash in 2008 in Chatsworth, Los Angeles, was the worst train crash in the history of California with 25 fatalities. The most common cause of death was due to chest injury (cardiac and aortic laceration) followed by head injury. This review could aid in improving passenger protection from head-on collision and in further development of head protection in train seats, as well as be useful in disaster planning and a benchmark for future rescue and triage operations.

Production of random DNA oligomers for scalable DNA computing.

While remarkably complex networks of connected DNA molecules can form from a relatively small number of distinct oligomer strands, a large computational space created by DNA reactions would ultimately require the use of many distinct DNA strands. The automatic synthesis of this many distinct strands is economically prohibitive. We present here a new approach to producing distinct DNA oligomers based on the polymerase chain reaction (PCR) amplification of a few random template sequences. As an example, we designed a DNA template sequence consisting of a 50-mer random DNA segment flanked by two 20-mer invariant primer sequences. Amplification of a dilute sample containing about 30 different template molecules allows us to obtain around 10(11) copies of these molecules and their complements. We demonstrate the use of these amplicons to implement some of the vector operations that will be required in a DNA implementation of an analog neural network.