Polyproline peptide targets Klebsiella pneumoniae polysaccharides to collapse biofilms

Hypervirulent Klebsiella pneumoniae is known for its increased extracellular polysaccharide production. Biofilm matrices of hypervirulent K. pneumoniae have increased polysaccharide abundance and are uniquely susceptible to disruption by peptide bactenecin 7 (bac7 (1-35)). Here, using confocal microscopy, we show that polysaccharides within the biofilm matrix collapse following bac7 (1-35) treatment. This collapse led to the release of cells from the biofilm, which were then killed by the peptide. Characterization of truncated peptide analogs revealed that their interactions with polysaccharide were responsible for the biofilm matrix changes that accompany bac7 (1-35) treatment. Ultraviolet photodissociation mass spectrometry with the parental peptide or a truncated analog bac7 (10-35) reveal the important regions for bac7 (1-35) complexing with polysaccharides. Finally, we tested bac7 (1-35) using a murine skin abscess model and observed a significant decrease in the bacterial burden. These findings unveil the potential of bac7 (1-35) polysaccharide interactions to collapse K. pneumoniae biofilms.

The National Brain Injury Rescue and Rehabilitation Study - a multicenter observational study of hyperbaric oxygen for mild traumatic brain injury with post-concussive symptoms

The National Brain Injury Rescue and Rehabilitation Project was established as a preliminary study to test the safety and practicality of multi-center hyperbaric oxygen administration for the post-concussive symptoms of chronic mild traumatic brain injury as a precursor to a pivotal, independent, multi-center, controlled clinical trial. This report presents the results for 32 subjects who completed a preliminary trial of hyperbaric oxygen several years before the passage of the 21 ^st Century Cures Act. This study anticipated the Act and its reassessment of clinical research. Subjects received 40-82 one-hour treatments at 1.5 atmospheres absolute 100% oxygen. Outcome measures included repeated self-assessment measures and automated neurocognitive tests. The subjects demonstrated improvement in 21 of 25 neurocognitive test measures observed. The objective neurocognitive test components showed improvement in 13 of 17 measures. Earlier administration of hyperbaric oxygen post injury, younger age at the time of injury and hyperbaric oxygen administration, military status, and increased number of hyperbaric oxygen administrations were characteristics associated with improved outcomes. There were no adverse events. Hyperbaric oxygen was found to be safe, inexpensive and worthy of clinical application in the 21 ^st Century model of facile data collection provided by recent research regulatory shifts in medicine. The study was approved by the ethics review committee of the Western Institutional Review Board (WIRB; Protocol #20090761).

Recovery from ocular ischemic syndrome after treatment with verapamil

Vasospasm has been implicated as a cause of amaurosis fugax, which can be controlled by administration of the calcium channel blockers nifedipine or verapamil. However, vasospasm has not previously been thought to be involved in chronic ocular ischemia. We report a patient with ocular ischemic syndrome, which may have had vasospasm as a contributing cause, since the patient also developed amaurosis fugax despite daily aspirin therapy. An 80-year-old man with chronic open-angle glaucoma developed chronic ocular ischemia characterized by progressively decreased visual acuity, pain, rubeosis, and hypotony, as well as transient visual dimming. Medical evaluation revealed no evidence of carotid stenosis, thromboembolism, or vasculitis as the cause of ocular ischemia. When the calcium channel blocker verapamil was administered, the episodes of transient visual dimming ceased immediately. In addition, soon thereafter, visual acuity improved, the rubeosis partially regressed, and the hypotony reversed. This case indicates that the calcium channel blocker verapamil may be effective in treating cases of ocular ischemic syndrome, when vasospasm is a contributing cause.

Blood loss measured with indium-111-labeled red blood cells in dogs

The authors describe a safe, simple, sensitive, and accurate technique of measuring moderate amounts of blood loss using erythrocytes labeled with indium-111. Donor red cells were labeled with indium-111 and tracer amounts infused into dogs. The magnitude of red cell loss was determined by the difference between two sequential volume measurements. The coefficient of variation of sequential measurements of the same red cell volume was 4.6 +/- 1%. The sensitivity of the technique, as determined by comparison of measured and estimated volumes, was 20.5 ml. The measured volume was related linearly to the calculated volume of red cells lost (r = 0.98). The authors recommend indium-111-labeled erythrocytes as a means of obtaining multiple measurements of small to moderate amounts of hemorrhage.