Rapid multiplex microfiber-based immunoassay for anti-MERS-CoV antibody detection.

On-site multiplex biosensors for innate immunity antibodies are ideal tools for monitoring health status of individuals against various diseases. This study introduces a novel antibody immunoassay testing platform incorporating microfiber-based arrays of antigens to capture specific antibodies. The fabrication and setup of the device revolved around electrospun polystyrene (ESPS) microfibers that act as three-dimensional membrane filters, capable of rapid and multifold analyte capture. In particular, the ESPS microfibers were patterned through localized oxygen plasma to create hydrophilic zones that facilitate fluid flows and immobilizations of antigens. The bulk of this robust antibody immunoassay platform could be installed into a compact syringe-driven cassette device, which could perform multiplex antibody immunoassay for antibodies specifically against Middle East respiratory syndrome coronavirus (MERS-CoV) with rapid preparation amounting to a total of 5 min, as well as high sensitivity and specificity for the MERS-CoV down to 200 µg/mL.

Fabrication and assessment of an electrospun polymeric microfiber-based platform under bulk flow conditions with rapid and efficient antigen capture.

Correction for 'Fabrication and assessment of an electrospun polymeric microfiber-based platform under bulk flow conditions with rapid and efficient antigen capture' by Carlton F. O. Hoy et al., Analyst, 2018, 143, 865-873.

Fabrication and assessment of an electrospun polymeric microfiber-based platform under bulk flow conditions with rapid and efficient antigen capture.

This study investigated the fabrication and proof of concept design demonstrating rapid and highly sensitive antigen capture utilizing electrospun polystyrene (PS) microfiber mat substrates paired with vacuum pump pressurization to induce bulk flow. In comparison with conventional flat PS surfaces used for immunoassay purposes, this system optimizes the increased surface area of the electrospun polystyrene (ESPS) fiber mat substrates and the accelerated propagation of the antigen through the detection platform by using a vacuum pump to enable efficient and rapid antigen capture. The novelty of this work was demonstrated through a parametric study detailing how a fiber substrate can capture antigen sensitively and at high speeds. In terms of sensitivity, the current system is comparable to the conventionally used flat PS substrates. Additionally, the amount of antigen captured on a flat PS substrate in 60 minutes was surpassed in under 5 seconds when utilizing the ESPS-vacuum system. Three-dimensional ESPS fiber mats were then noted as a comparison between Damkohler numbers and between flat PS and ESPS-vacuum systems. The bulk flow of the ESPS-vacuum system allows for a Damkohler number of 0.37 indicating a balance between the flow rate and the reaction rate as opposed to a PS flat platform of 5.80 × 104 which illustrates a diffusion rate limited system. Finally, the overall ESPS-vacuum system was tested for its immunoassay capability. A sandwich fluorescence-based immunoassay was performed on both PS flat-diffusion and ESPS-vacuum systems. The ESPS-vacuum system indicated a wider detection range capability from 5 to 1000 ng mL-1 in comparison with the PS flat-diffusion system at 5 to 100 ng mL-1.

Fabrication and control of CT number through polymeric composites based on coronary plaque CT phantom applications.

Biomedical phantoms are commonly used for various medical imaging modalities to improve imaging quality and procedures. Current biomedical phantoms fabricated commercially are high in cost and limited in the specificity of human environments and structures that can be mimicked. This study aimed to control the measurable computed tomography (CT) number in Hounsfield units through polymeric biomedical phantom materials using controlled amounts of hydroxyapatite (hA). The purpose was to fabricate CT phantoms capable of mimicking various coronary plaque types while introducing a fabrication technique and basis for a numerical model to which the technique may be applied. The CT number is tunable based on the controlled material properties of electron density and atomic numbers. Three different polymeric matrices of polyethylene (PE), thermoplastic polyurethane (TPU), and polyvinylidene fluoride (PVDF) were selected due to their varied specific densities and ease of fabrication acting as integral properties for CT phantom fabrication. These polymers were processed together with additions of hA in mass percentages of 2.5, 5, 10, and 20% hA as well as a 0% hA as a control for each polymeric material. By adding hA to PE, TPU, and PVDF an increasing trend was exhibited between CT number and weight percent of hA.

Comparison of monodisperse droplet generation in flow-focusing devices with hydrophilic and hydrophobic surfaces.

A thin flow-focusing microfluidic channel is evaluated for generating monodisperse liquid droplets. The microfluidic device is used in its native state, which is hydrophilic, or treated with OTS to make it hydrophobic. Having both hydrophilic and hydrophobic surfaces allows for creation of both oil-in-water and water-in-oil emulsions, facilitating a large parameter study of viscosity ratios (droplet fluid/continuous fluid) ranging from 0.05 to 96 and flow rate ratios (droplet fluid/continuous fluid) ranging from 0.01 to 2 in one geometry. The hydrophilic chip provides a partially-wetting surface (contact angle less than 90°) for the inner fluid. This surface, combined with the unusually thin channel height, promotes a flow regime where the inner fluid wets the top and bottom of the channel in the orifice and a stable jet is formed. Through confocal microscopy, this fluid stabilization is shown to be highly influenced by the contact angle of the liquids in the channel. Non-wetting jets undergo breakup and produce drops when the jet is comparable to or smaller than the channel thickness. In contrast, partially-wetting jets undergo breakup only when they are much smaller than the channel thickness. Drop sizes are found to scale with a modified capillary number based on the total flow rate regardless of wetting behavior.

Three dimensional drop tracking flow chamber for coalescence studies.

We have developed a novel flow chamber which imposes a controlled axisymmetric stagnation flow to enable the study of external flow effects on coalescence dynamics. This system allows for the first time the precise positioning of a drop in a three dimensional flow and additionally enforces a highly symmetric flow around the drop. We focus on the study of a single drop approaching a stationary flat plane as this is analogous to two drops approaching each other. A single drop is created and then guided along the unsteady center line of a stagnation flow. The real time computer control algorithm analyzes video images of the drop in two orthogonal planes and manipulates flow restricting valves along the four outlets of the flow. We demonstrate using particle image velocimetry that the computer control not only controls the drop position but also ensures a symmetric flow inside the flow chamber. This chamber will enable a detailed investigation of the drainage of the thin film between the drop and the lower surface in order to probe the effect of external flow on coalescence.

Experimental investigation of the spontaneous wetting of polymers and polymer blends.

The dynamics of polymeric liquids and mixtures spreading on a solid surface have been investigated on completely wetting and partially wetting surfaces. Drops were formed by pushing the test liquid through a hole in the underside of the substrate, and the drop profiles were monitored as the liquid wet the surface. Silicon surfaces coated with diphenyldichlorosilane (DPDCS) and octadecyltrichlorosilane (OTS) were used as wetting and partial wetting surfaces, respectively, for the fluids we investigated. The response under complete and partial wetting conditions for a series of polypropylene glycols (PPG) with different molecular weights and the same surface tension could be collapsed onto a single curve when scaling time based on the fluid viscosity, the liquid-vapor surface tension, and the radius of a spherical drop with equivalent volume. A poly(ethylene glycol) (PEG300) and a series of poly(ethylene oxide-rand-propylene oxide) copolymers did not show the same viscosity scaling when spread on the partially wetting surface. A combined model incorporating hydrodynamic and molecular-kinetic wetting models adequately described the complete wetting results. The assumptions in the hydrodynamic model, however, were not valid under the partial wetting conditions in our work, and the molecular-kinetic model was chosen to describe our results. The friction coefficient used in the molecular-kinetic model exhibited a nonlinear dependence with viscosity for the copolymers, indicating a more complex relationship between the friction coefficient and the fluid viscosity.

The bispectral index monitor: a new tool for air medical personnel.

The bispectral index monitor (BIS) is commonly used in the operating room to help anesthesiologists quantitate the level of anesthesia. The BIS has been shown to reduce the incidence of anesthetic overuse and decrease costs. The device has made its way into critical care areas, where it has proven effective in monitoring sedation levels, specifically in reducing the incidence of oversedation. This article explores the possibility of using the monitor in the air medical environment.

Recent advances in the pharmacologic management of diabetes mellitus.

The importance of glucose control in reducing the complications of diabetes mellitus has been clearly demonstrated. The emergency physician routinely is expected to treat a wide range of problems related to this disease, including making the initial diagnosis of type 2 and occasionally type 1 diabetes. Also common are patients with poorly controlled diabetes. The recent introduction of new classes of agents to lower blood glucose, especially in type 2 diabetes, should improve the control in this category of patient and reduce the complication rate. Some of these agents, such as troglitazone, have potentially fatal complications and require careful monitoring. Emergency physicians should be aware of the common complications of these drugs because patients can present to the ED with them. Hypoglycemia, a common cause of 911 calls and emergency visits, is not a side effect of either metformin or acarbose. Insulin lispro has improved postprandial glycemic control for type 1 and some insulin-requiring type 2 diabetics. Hypoglycemia is less of a risk with insulin lispro, and quality of life is better with this rapidly acting insulin. Newer methods of insulin delivery, such as continuous subcutaneous infusion, have greatly improved glucose control, given greater freedom to patients, and reduced the risks of hypoglycemia.

Prevalence of atypical chest pain descriptions in a population from the southern United States.

INTRODUCTION: The character of chest pain (CP) is a major factor determining triage and admission for patients presenting to the emergency department (ED). Previous studies have found atypical descriptions in as little as 10-15% of patients with true myocardial ischemic pain. Atypical descriptions may be more prevalent in the Deep South of the United States because of cultural differences in the semantic description of pain. METHODS: A retrospective study of patients presenting to the ED of a southern U.S. urban hospital with enzyme-documented myocardial infarction was conducted to determine the prevalence of atypical CP descriptions. A multivariate analysis of those patients with atypical pain descriptions was conducted to determine the independent demographic factors associated with these descriptions. RESULTS: In a total of 77 subjects (56% black; 44% white) meeting the study criteria, 43% were found to have atypical elements in the character of their CP descriptions. Only the black race demographic was found to be significantly correlated with the atypical descriptions. The use of the descriptive term "sharp" accounted for nearly half of the atypical presentations. CONCLUSION: Regional differences in the description of the character of CP may result in misleading portrayals of ischemic heart disease in southern U.S. populations. These differences are associated with a higher prevalence of atypical CP because of semantic distinctions, such as the use of the term "sharp" as a descriptor of acuity rather than character or quality.

The use of chemical restraint in helicopter transport.

INTRODUCTION: Helicopter transport of the combative patient is a major safety hazard facing air medical teams. Although physical restraints alone are helpful, the addition of chemical restraint (CR) often is necessary to control these patients while in flight. METHODS: A survey was conducted to determine the current practices of using nonparalyzing CR in air medical transport programs nationwide. The survey consisted of 24 questions on the use of CR during transport. Each U.S. program belonging to the Association of Air Medical Services was contacted by telephone, and a flight nurse or paramedic provided answers based on personal experience and statistics compiled by his or her individual program. RESULTS: Of the 100 programs responding, benzodiazepines were used most commonly to control agitation with 51% using micazolam. Patients with a head injury required CR more frequently than any other condition (73%). Crews flying larger aircraft reported less need for CR. A physician order was required by only 30% of the programs, but delays infrequently endangered the patient (2%). Only 7% of the responding programs had a patient whose condition deteriorated because of CR. CONCLUSION: CR is necessary in air medical transport. Most programs use short-acting benzodiazepines. Crews in smaller aircraft use CR more frequently, and head injury is the most common condition requiring such restraint.

Methcathinone intoxication in the rat: abrogation by dextrorphan.

STUDY OBJECTIVE: Methcathinone, a designer drug, has high abuse liability. In this study we characterized acute methcathinone toxicity in rats, attempting to determine whether the excitatory amino acid receptor antagonist dextrorphan can antagonize methcathinone intoxication. METHODS: Intoxication was produced with IV methcathinone infusion (5 mg/kg/minute; 100 mg/mL) in conscious rats. We studied pretreatment, in which dextrorphan or vehicle was injected 30 minutes before methcathinone infusion. In a second protocol, dextrorphan or saline solution was given immediately after the onset of convulsions. RESULTS: Methcathinone caused tachycardia (maximal increase, 131 +/- 10 beats/minute), hyperthermia (+2.3 degrees C), convulsions, and cardiorespiratory collapse in vehicle-pretreated rats (n = 9). Death occurred after 32.0 +/- 1.1 minutes of infusion. Dextrorphan pretreatment (25 mg/kg; n = 7) significantly reduced hyperthermia (+.1 degree +/- .3 degree C) and tachycardia and increased the convulsive (dextrorphan, 134 +/- 9 mg/kg; vehicle, 67 +/- 4 mg/kg) and lethal doses (dextrorphan, 204 +/- 9 mg/kg; vehicle, 160 +/- 5 mg/kg). Dextrorphan, given immediately after the initial methcathinone convulsion, reduced hyperthermic and tachycardic responses but not the lethality of methcathinone. CONCLUSION: Blockade of excitatory amino acid receptors by dextrorphan minimizes acute methcathinone intoxication.

Phenytoin hypersensitivity syndrome.

The purpose of the current manuscript is to familiarize the primary physician with the presentation of phenytoin hypersensitivity syndrome, and to discuss management options. A review of all admissions to the University of Mississippi Medical Center over a five year period revealed 4 cases of phenytoin hypersensitivity syndrome. These cases are presented and the phenytoin hypersensitivity syndrome, characterized most commonly by fever, cutaneous eruption and lymphadenopathy, is described. It is emphasized that the clinician must be aware of the syndrome and must recognize it on presentation. Theories regarding etiology and treatment options are discussed. It is recommended that all patients with symptoms of phenytoin hypersensitivity syndrome be hospitalized and that steroids be initiated.

Diagnosis of thoracic outlet syndrome in the emergency department.

The use of the emergency department (ED) as a source for primary care has increased the number of patients seen in this setting with even chronic symptoms such as pain, paresthesias, and weakness in the upper extremity. This group may include individuals with thoracic outlet syndrome (TOS). We were concerned that TOS may be underdiagnosed in the ED because of physician unfamiliarity with the signs and symptoms of TOS. Hence, we retrospectively studied cases of TOS seen at the ED of the University hospital during a 29-year period. We believe this is the first report in the English language literature to reflect the assessment and management of TOS in the ED. The study data include clinical presentation, diagnostic tests, and management of TOS. Lack of thorough evaluation resulted in underdiagnosis of TOS in our ED. We recommend that ED personnel pay close attention to patients with symptoms of long duration and that ED physicians be aware of TOS presentation and its management.

Heat emergencies.

Heat emergencies occur when the body is unable to adequately dissipate heat. Hyperthermic patients should be cooled immediately with a lukewarm-water spray and cool moving air. Patients with heat exhaustion respond well to administration of intravenous fluids. Patients with heatstroke have a complete loss of thermoregulation, a core temperature greater than 40.5 degrees C (105 degrees F) and impaired mental status. These critically ill patients must be cooled quickly to 39 degrees C (102 degrees F) to avoid devastating complications. Intensive care monitoring and support are indicated. To reduce the risk of heat injury in hot weather, frail and elderly persons must maintain hydration and may need to consider alternate living arrangements. Laborers, athletes and military personnel benefit from gradual acclimation to the heat, increased fluid intake, vapor-permeable clothing and frequent rest periods.

Evaluation of alimentary tract foreign body: clinical and imaging review of 100 consecutive cases.

We investigated the cases of 100 consecutive patients with alimentary tract foreign bodies for clinical findings and use of imaging and compared our findings with those of other reported series. Most of our patients were children, and the alimentary tract foreign body was metal in most cases. There was no undue morbidity or mortality related to either conservative or interventional treatment. Imaging was useful in diagnosis and management of cases. Use of computed tomography and magnetic resonance imaging in evaluation of alimentary tract foreign bodies is discussed.

Gastric emptying in the acutely inebriated patient.

Fifty inebriated emergency department (ED) patients underwent evacuation of gastric contents via a nasogastric tube, in order to determine if a significant amount of ingested ethanol can be removed prior to absorption. Such a result could potentially reduce additional intoxicating effect. The gastric contents were assayed for total ethanol concentration, and a potential (postabsorption) additive blood alcohol level (PABAL) was projected and compared to the actual BAL on arrival. The type of beverage ingested and the time since last drink were recorded. BAL ranged from 108 to 637 mg/dL (mean +/- SD, 290 +/- 104.7). Gastric aspirate volume ranged from 50 to 700 mL (190 +/- 134), and contained alcohol in a range of 87 to 2271 mg/dL (475 +/- 479). Based on the distribution volume for alcohol calculated according to the patient's weight, this corresponded to a PABAL of 3 to 167 mg/dL (mean, 24.3 +/- 29.3). There was no significant correlation between the volume or concentration of gastric aspirate and the patient's stated drinking history. The authors conclude that a significant amount of ingested alcohol may occasionally be removed from absorption by the routine evacuation of gastric contents in intoxicated patients. These patients cannot be identified upon presentation, however, and these data cannot support routine use of gastric emptying in the detoxification of inebriated patients.