Identification of 5-(Aryl/Heteroaryl)amino-4-quinolones as Potent Membrane-Disrupting Agents to Combat Antibiotic-Resistant Gram-Positive Bacteria.

Nosocomial infections caused by resistant Gram-positive organisms are on the rise, presumably due to a combination of factors including prolonged hospital exposure, increased use of invasive procedures, and pervasive antibiotic therapy. Although antibiotic stewardship and infection control measures are helpful, newer agents against multidrug-resistant (MDR) Gram-positive bacteria are urgently needed. Here, we describe our efforts that led to the identification of 5-amino-4-quinolone 111 with exceptionally potent Gram-positive activity with minimum inhibitory concentrations (MICs) ≤0.06 µg/mL against numerous clinical isolates. Preliminary mechanism of action and resistance studies demonstrate that the 5-amino-4-quinolones are bacteriostatic, do not select for resistance, and selectively disrupt bacterial membranes. While the precise molecular mechanism has not been elucidated, the lead compound is nontoxic displaying a therapeutic index greater than 500, is devoid of hemolytic activity, and has attractive physicochemical properties (clog P = 3.8, molecular weight (MW) = 441) that warrant further investigation of this promising antibacterial scaffold for the treatment of Gram-positive infections.

Proof-of-Concept: A Hands-Free Interface for Robot-Assisted Self-Feeding.

Eating and drinking is an essential part of every-day life. And yet, there are many people in the world today who rely on others to feed them. In this work, we present a prototype robot-assisted self-feeding system for individuals with movement disorders. The system is capable of perceiving, localizing, grasping, and delivering non-compliant food items to an individual. We trained an object recognition network to detect specific food items, and we compute the grasp pose for each item. Human input is obtained through an interface consisting of an eye-tracker and a display screen. The human selects options on the monitor with their eye and head movements and triggers responses with mouth movements. We performed a pilot study with four able-bodied participants and one participant with a spinal cord injury (SCI) to evaluate the performance of our prototype system. Participants selected food items with their eye movements, which were then delivered by the robot. We observed an average overall feeding success rate of 89.1% and an average overall task time of $31.4 \pm 2.4$ seconds per food item. The SCI participant gave scores of 90.0 and 8.3 on the System Usability Scale and NASA Task Load Index, respectively. We also conducted a custom, post-study interview to gather participant feedback to drive future design decisions. The quantitative results and qualitative user feedback demonstrate the feasibility of robot-assisted self-feeding and justify continued research into mealtime-related assistive devices.

Controlling an effector with eye movements: The effect of entangled sensory and motor responsibilities.

Restoring arm and hand function has been indicated by individuals with tetraplegia as one of the most important factors for regaining independence. The overall goal of our research is to develop assistive technologies that allow individuals with tetraplegia to control functional reaching movements. This study served as an initial step toward our overall goal by assessing the feasibility of using eye movements to control the motion of an effector in an experimental environment. We aimed to understand how additional motor requirements placed on the eyes affected eye-hand coordination during functional reaching. We were particularly interested in how eye fixation error was affected when the sensory and motor functions of the eyes were entangled due to the additional motor responsibility. We recorded participants' eye and hand movements while they reached for targets on a monitor. We presented a cursor at the participant's point of gaze position which can be thought of as being similar to the control of an assistive robot arm. To measure eye fixation error, we used an offline filter to extract eye fixations from the raw eye movement data. We compared the fixations to the locations of the targets presented on the monitor. The results show that not only are humans able to use eye movements to direct the cursor to a desired location (1.04 ± 0.15 cm), but they can do so with error similar to that of the hand (0.84 ± 0.05 cm). In other words, despite the additional motor responsibility placed on the eyes during direct eye-movement control of an effector, the ability to coordinate functional reaching movements was unaffected. The outcomes of this study support the efficacy of using the eyes as a direct command input for controlling movement.

Toll-like receptor 7 and 8 imidazoquinoline-based agonist/antagonist pairs.

Toll-like receptors (TLRs) 7 and 8 are key targets in the development of immunomodulatory drugs for treating infectious disease, cancer, and autoimmune disorders. These receptors can adopt both agonist and antagonist binding conformations that switch the receptor signal on or off to the downstream production of cytokines. In this study, we examined the effect of simple isomeric substitutions to the C2-butyl group of two imidazoquinoline agonists and evaluated the activity of these analogs using both TLR7 and TLR8 reporter cells and cytokine induction assays. Results are presented showing the C2-isobutyl and C2-cyclopropylmethyl isomers are both mixed TLR7/8 competitive antagonists of the parent agonist [4-Amino-1-(4-(aminomethyl)benzyl)-2-butyl-7-methoxycarbonyl-1H-imidazo[4,5-c]quinoline], indicating the conformation of the dimeric receptor complex is highly sensitive to steric perturbations to the ligand binding pocket. This observation is consistent with prior work demonstrating TLR7 and TLR8 activity is directly correlated to C2-alkyl substitutions that project into a hydrophobic pocket at the dimer interface of the receptor. The close structural relationship of the agonist/antagonist pairs identified here highlights the importance of this pocket in tipping the balance between the agonist and antagonist binding states of the receptor which may have significant ramifications to the design of imidazoquinoline-based immunomodulatory agents.

Structural Basis of Polyketide Synthase O-Methylation.

Modular type I polyketide synthases (PKSs) produce some of the most chemically complex metabolites in nature through a series of multienzyme modules. Each module contains a variety of catalytic domains to selectively tailor the growing molecule. PKS O-methyltransferases ( O-MTs) are predicted to methylate ß-hydroxyl or ß-keto groups, but their activity and structure have not been reported. We determined the domain boundaries and characterized the catalytic activity and structure of the StiD and StiE O-MTs, which methylate opposite ß-hydroxyl stereocenters in the myxobacterial stigmatellin biosynthetic pathway. Substrate stereospecificity was demonstrated for the StiD O-MT. Key catalytic residues were identified in the crystal structures and investigated in StiE O-MT via site-directed mutagenesis and further validated with the cyanobacterial CurL O-MT from the curacin biosynthetic pathway. Initial structural and biochemical analysis of PKS O-MTs supplies a new chemoenzymatic tool, with the unique ability to selectively modify hydroxyl groups during polyketide biosynthesis.

Intra-discal injection of autologous, hypoxic cultured bone marrow-derived mesenchymal stem cells in five patients with chronic lower back pain: a long-term safety and feasibility study.

BACKGROUND: Chronic low back pain due to disc degeneration represents a major social and economic burden worldwide. The current standard of care is limited to symptomatic relief and no current approved therapy promotes disc regeneration. Bone marrow-derived mesenchymal stem cells (MSCs) are easily accessible and well characterized. These MSCs are multipotent and exhibit great tissue regenerative potential including bone, cartilage, and fibrous tissue regeneration. The use of this cell-based biologic for treating protruding disc herniation and/or intervertebral disc degeneration is a promising therapeutic strategy, due to their known regenerative, immuno-modulatory and anti-inflammatory properties. METHODS: Five patients diagnosed with degenerative disc disease received an intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells (15.1-51.6 million cells) as part of a previous study. These patients were re-consented to participate in this study in order to assess long-term safety and feasibility of intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells 4-6 years post mesenchymal stem cell infusion. The follow-up study consisted of a physical examination, a low back MRI, and a quality of life questionnaire. RESULTS: Patients' lower back MRI showed absence of neoplasms or abnormalities surrounding the treated region. Based on the physical examination and the quality of life questionnaire, no adverse events were reported due to the procedure or to the stem cell treatment 4-6 years post autologous, hypoxic cultured mesenchymal stem cell infusion. All patients self-reported overall improvement, as well as improvement in strength, post stem cell treatment, and four out of five patients reported improvement in mobility. CONCLUSION: This early human clinical data suggests the safety and feasibility of the clinical use of hypoxic cultured bone marrow-derived mesenchymal stem cells for the treatment of lower back pain due to degenerative disc disorders and support further studies utilizing hypoxic cultured bone marrow-derived stem cells. The overall improvements reported are encouraging, but a larger double-blind, controlled, randomized clinical study with significant number of patients and implementation of validated endpoint measurements are next steps in order to demonstrate efficacy of this cell-based biologic.

Safety and complications reporting update on the re-implantation of culture-expanded mesenchymal stem cells using autologous platelet lysate technique.

UNLABELLED: Mesenchymal stem cells (MSCs) hold great promise as therapeutic agents in regenerative medicine. Numerous animal studies have documented the multipotency of MSCs, showing their capabilities for differentiating into orthopedic tissues such as muscle, bone, cartilage, and tendon. However, the safety of culture expanded MSC's for human use has only just begun to be reported. METHODS: Between 2006 and 2010, two groups of patients were treated for various orthopedic conditions with culture-expanded, autologous, bone marrow-derived MSCs (group 1: n=50; group 2: n=290-one patient in both groups). Cells were cultured in monolayer culture flasks using an autologous platelet lysate technique and re-injected into peripheral joints or into intervertebral discs with use of c-arm fluoroscopy. While both groups had prospective surveillance for complications, Group 1 additionally underwent 3.0T MRI tracking of the re-implant sites. RESULTS: The mean age of patients treated was 53 +/- 13.85 years; 214 were males and 125 females with mean follow-up time from any procedure being 435 days +/- 261 days. Number of contacts initiated based on time from first procedure was 482 at 3 months, 433 at 6 months, 316 contacts at 12 months, 110 contacts at 24 months, and 22 contacts at 36 months. For Group 1, 50 patients underwent 210 MRI surveillance procedures at 3 months, 6 months, 1, 2, and 3 years which failed to demonstrate any tumor formation at the re-implant sites. Formal disease surveillance for adverse events based on HHS criteria documented significantly less morbidity than is commonly reported for more invasive surgical procedures, all of which were either self-limited or were remedied with therapeutic measures. Two patients were diagnosed with cancer out of 339 patients treated since study inception; however, this was almost certainly unrelated to the MSC therapy and the neoplasm rate in similar to that seen in the U.S. Caucasian population. Knee outcome data was collected on a subset of patients. Here, > 75% improvement was reported in 41.4% while decreasing the improvement threshold to > 50% improvement, 63.2% reported an improvement. At an average reporting time of 11.3 months from first procedure average reported relief in the knee sample equaled 53.1% (n=133 reporting). CONCLUSIONS: Using both intensive high field MRI tracking and complications surveillance in 339 patients, no neoplastic complications were detected at any stem cell re-implantation site. These findings are consistent with our prior publication and other published reports that also show no evidence of malignant transformation in vivo, following implantation of MSCs for orthopedic use.

Safety and complications reporting on the re-implantation of culture-expanded mesenchymal stem cells using autologous platelet lysate technique.

UNLABELLED: ABSTRUCT: Mesenchymal stem cells (MSCs) hold great promise as therapeutic agents in regenerative medicine. Numerous animal studies have documented the multipotency of MSCs, showing their capabilities for differentiating into orthopedic tissues such as muscle, bone, cartilage, and tendon. However, the complication rate for autologous MSC therapy is only now beginning to be reported. METHODS: Between 2005 and 2009, two groups of patients were treated for various orthopedic conditions with culture-expanded, autologous, bone marrow-derived MSCs (group 1: n=45; group 2: n=182). Cells were cultured in monolayer culture flasks using an autologous platelet lysate technique and re-injected into peripheral joints (n=213) or into intervertebral discs (n=13) with use of c-arm fluoroscopy. While both groups had prospective surveillance for complications, Group 1 additionally underwent 3.0T MRI tracking of the re-implant sites. RESULTS: Mean follow-up from the time of the re-implant procedure was 10.6 +/- 7.3 months. Serial MRI's at 3 months, 6 months, 1 year and 2 years failed to demonstrate any tumor formation at the re-implant sites. Formal disease surveillance for adverse events based on HHS criteria documented 7 cases of probable procedure-related complications (thought to be associated with the re-implant procedure itself) and three cases of possible stem cell complications, all of which were either self-limited or were remedied with simple therapeutic measures. One patient was diagnosed with cancer; however, this was almost certainly unrelated to the MSC therapy. CONCLUSIONS: Using both high field MRI tracking and general surveillance in 227 patients, no neoplastic complications were detected at any stem cell re-implantation site. These findings are consistent with other reports that also show no evidence of malignant transformation in vivo, following implantation of MSCs that were expanded in vitro for limited periods.

Ethnicity and the distance to the epidural space in parturients.

BACKGROUND AND OBJECTIVES: In a pilot study, we previously demonstrated a higher average skin to lumbar epidural space distance (STLESD) in our obstetric population compared with the published literature. Furthermore, we demonstrated differences in STLESD based on ethnicity. The aim of this study was to perform a comprehensive analysis of the STLESD in our patient population by expanding the number of patients and ethnic groups included. METHODS: Data from 3,305 patients were obtained from our electronic database from September 2003 through November 2005. Self-declared ethnicity included 1,177 Caucasians (36%), 1,162 African Americans (35%), 760 Hispanics (23%), 135 Asians (4%), and 71 Indian/Pakistani/Bangladeshi/Sri Lankans (2%). The influences of body mass index (BMI), ethnicity, and their interaction on the STLESD were tested with a multiple linear regression model. RESULTS: The mean +/- SD STLESD differed among the ethnic groups ranging from 4.8 +/- 0.9 cm in Asian patients to 6.3 +/- 1.6 cm in African American parturients. When all ethnic groups were compared, BMI had a significant influence on STLESD (P < .0001), but so did ethnicity (P = .0004). The Hispanic group demonstrated STLESDs that were significantly lower than the African American and Caucasian groups at high BMI (P < .0001). In a subanalysis performed without the Hispanic group, the influence of BMI on STLESD was found to be similar for each group. In this subanalysis, the African American group had STLESDs that were deeper compared with the other 3 ethnic groups (P < .0001), regardless of BMI. CONCLUSIONS: In this study we found that the STLESD was deeper than what was previously reported in the literature. Furthermore, ethnicity, in addition to BMI, influenced the STLESD.

Detecting an infiltrated intravenous catheter using indigo carmine: a novel method.

An extravasated IV catheter may have serious clinical consequences. These include the inability to circulate emergency medications, cause pain on injection, infection at the site, and tissue damage. Clinical signs such as swelling, redness, and pain with injection are valuable, but may not be helpful in the presence of obesity, edema, or in a tracheally intubated and sedated patient. Here we describe a case illustrating a novel approach in which we used an IV dye injection (indigo carmine) to detect a correctly placed and then an extravasated IV. The ability to see visible flow of IV dye intravascularly helped confirm the correct placement. The technique we describe is quick, safe, and inexpensive.

Partial regeneration of the human hip via autologous bone marrow nucleated cell transfer: A case study.

HISTORY: This is a case report of a 64-year-old white male with a 20 year history of unilateral hip pain that had become debilitating over the last several years. On intake, Harris hip score was rated as: Pain subscale = 10, Function subscale = 32, Deformity subscale = 4, Motions subscale = 4.775 with a total score of 50.8 out of 100. MRI of the affected hip showed severe degeneration with spurring, decrease in joint space, and several large subchondral cysts. The patient had been evaluated by an orthopedic surgeon and told he was a candidate for bipolar hip replacement. METHOD: Two autologous nucleated cell collections were performed from bone marrow with subsequent isolation and transfers into the intra-articular hip using a hyaluronic acid and thrombin activated platelet rich plasma scaffold. Marrow samples were processed by centrifugation and lysis techniques to isolate nucleated cells. CONCLUSION: This report describes partial by articular surface regeneration 8 weeks after intraarticular bone marrow transfer. Post-op 3.0T FGRE MRI showed neocortex formation when compared to immediate pre-op MRI and objective improvements were noted that coincided with subjective reports of improvement.

Behavioural testing and histological assessments of rabbit spinal cord following intrathecal administration of ondansetron.

1. Intrathecal injection of ondansetron has the potential to reduce opioid-related side-effects. The aim of the present study was to determine whether this route of administration produces neuraxial injury. 2. Adult, non-pregnant female New Zealand white rabbits received a single bolus injection of a low (40 microg) or high (4.0 mg) dose of ondansetron into the intrathecal space between the 4th and 5th lumbar vertebrae. In some cases, ondansetron was coadministered with morphine (5 microg/kg). Control animals received a bolus injection of normal saline. Behavioural assessments were conducted at 1 and 24 h to determine overt changes in arousal and mobility, followed by histological evaluation of the excised spinal cord. 3. Of 45 animals investigated, 10 rabbits exhibited modest behavioural evidence of spinal injury, the incidence of which was equally distributed between the treatment groups. Haematoxylin and eosin, along with HAM56, staining of cross-sections of the cervical, thoracic and upper and lower lumbar areas revealed mild signs of inflammation. This, too, was equally distributed between the treatment groups, suggesting that any observed neuraxial injury was the result of needle trauma and not ondansetron neurotoxicity. 4. Collectively, these negative findings support conducting further experiments to fully assess the clinical usefulness of intrathecal ondansetron administration.

Mapping the critical diastolic pathway in intra-atrial reentrant tachycardia using an automated voltage mapping program.

This case report demonstrates the use of an automated voltage mapping algorithm to facilitate the rapid mapping of the low-voltage zone and isolate the critical diastolic pathway of an intra-atrial reentrant tachycardia circuit. Catheter ablation targeted to this pathway successfully terminated the arrhythmia.

Use of a modifier reduces inconsistency in the American Society of Anesthesiologists Physical Status Classification in parturients.

In this study, we sought to determine whether there is a significant discrepancy among a group of practitioners when rating pregnant patients using the ASA Physical Status Classification and whether this discrepancy could be resolved with the addition of a modifier for pregnancy. Our results indicate that significant discrepancy occurs and that it is reduced with the use of the modifier, especially when referring to the healthy parturient.

Characterization of the infarct substrate and ventricular tachycardia circuits with noncontact unipolar mapping in a porcine model of myocardial infarction.

BACKGROUND: Conventional mapping of ventricular tachycardia (VT) after myocardial infarction is limited in patients with hemodynamically untolerated or noninducible VT. OBJECTIVES: The purpose of this study was to develop a unique strategy using noncontact unipolar mapping to define infarct substrate and VT circuits. METHODS: Dynamic substrate mapping (DSM) was performed in seven pigs with healed anterior myocardial infarction. This technique defined substrate as the intersection of low-voltage areas identified in sinus rhythm and during pacing around the infarct. Pacing was also performed within the substrate to determine exit sites. RESULTS: Anteroapical transmural scar was identified in all animals. A mean of three pacing sites was used for substrate definition. The mean area (+/- SD) was 18.4 +/- 8.8 cm2 by DSM and 15.4 +/- 6.9 cm2 by pathology (P >.5). A mean of 4.5 sites was paced within substrate. Ten of 18 paced wavefronts exited substrate adjacent to the pacing area, seven exited at distant areas, and one had two exits. VT was induced in five animals (1.6 morphologies per animal). Except for one VT, circuit exit sites were identified at substrate borders on the endocardium. VT exit sites were at (n = 6) or near (n = 3) a pacing exit site. Electrogram voltages differed significantly between substrate, border, and nonsubstrate areas in infarcted animals and in comparison with control animals. No substrate was identified in two control animals. CONCLUSION: DSM is a reliable method for infarct substrate localization in this model. Pacing within substrate can predict VT exit sites and may prove useful for ablation of unmappable VT after myocardial infarction.