Endoscopic sleeve gastroplasty requiring conversion to partial gastrectomy with paraesophageal hernia repair.

Endoluminal bariatric surgery has lower costs and perceived risks compared to traditional surgery. Endoluminal procedures are a newer approach to weight loss but long-term outcomes and complications continue to emerge. This case report is an endoscopic sleeve gastroplasty that resulted in a paraesophageal hernia repair with removal of gastroplasty sutures and partial gastrectomy.

Colorectal Cancer Screening and Race in an Equal Access Medical System.

National colorectal cancer (CRC) screening rates have improved, but significant racial disparities have been identified. Improved access to care has been proposed as a solution to eliminate such disparities. To determine if racial disparities in CRC screening rates persist in a medical system without barriers to access or cost. A retrospective review study was performed, examining the healthcare effectiveness data and information set data from patients between the ages of 50 and 65 years who were eligible for CRC screening. Data on the type of CRC screening and rates of up-to-date screening were also examined. Data were available for 14,196 patients of whom 8809 (62%) reported race. Subjects included were 53% male and 47% female, with breakdown by race as follows: 53% White, 34% Asian/Pacific Islander, 11% Black, 1% Hispanic, and <1% Native-American. Overall, CRC screening and up-to-date rates were higher than the national average (81 and 72%, respectively). Blacks were less likely than non-Blacks to have undergone CRC screening (75 vs. 82%, p < 0.001), and were also less likely to be up-to-date with CRC screening (66 vs. 72%, p < 0.001). Despite elimination of access and cost barriers, racial disparities in CRC screening persist. Equal access to CRC screening tools will be necessary, but not sufficient, to eliminate the currently observed national trends. Further study should focus on elucidating patient-specific barriers to successful completion and maintenance of CRC screening.

A Cell Phone-Based Microphotometric System for Rapid Antimicrobial Susceptibility Testing.

This study demonstrates a low-cost, portable diagnostic system for rapid antimicrobial susceptibility testing in resource-limited settings. To determine the antimicrobial resistance phenotypically, the growth of pathogens in microwell arrays is detected under different antibiotic conditions. The use of a colorimetric cell viability reagent is shown to significantly improve the sensitivity of the assay compared with standard absorbance spectroscopy. Gas-permeable microwell arrays are incorporated for facilitating rapid bacterial growth and eliminating the requirement of bulky supporting equipment. Antibiotics can also be precoated in the microwell array to simplify the assay protocol toward point-of-care applications. Furthermore, a low-cost cell phone-based microphotometric system is developed for detecting the bacterial growth in the microwell array. By optimizing the operating conditions, the system allows antimicrobial susceptibility testing for samples with initial concentrations from 10(1) to 10(6) cfu/mL. Using urinary tract infection as the model system, we demonstrate rapid antimicrobial resistance profiling for uropathogens in both culture media and urine. With its simplicity and cost-effectiveness, the cell phone-based microphotometric system is anticipated to have broad applicability in resource-limited settings toward the management of infectious diseases caused by multidrug-resistant pathogens.

Enhanced nucleic acid amplification with blood in situ by wire-guided droplet manipulation (WDM).

There are many challenges facing the use of molecular biology to provide pertinent information in a timely, cost effective manner. Wire-guided droplet manipulation (WDM) is an emerging format for conducting molecular biology with unique characteristics to address these challenges. To demonstrate the use of WDM, an apparatus was designed and assembled to automate polymerase chain reaction (PCR) on a reprogrammable platform. WDM minimizes thermal resistance by convective heat transfer to a constantly moving droplet in direct contact with heated silicone oil. PCR amplification of the GAPDH gene was demonstrated at a speed of 8.67 s/cycle. Conventional PCR was shown to be inhibited by the presence of blood. WDM PCR utilizes molecular partitioning of nucleic acids and other PCR reagents from blood components, within the water-in-oil droplet, to increase PCR reaction efficiency with blood in situ. The ability to amplify nucleic acids in the presence of blood simplifies pre-treatment protocols towards true point-of-care diagnostic use. The 16s rRNA hypervariable regions V3 and V6 were amplified from Klebsiella pneumoniae genomic DNA with blood in situ. The detection limit of WDM PCR was 1 ng/µL or 10(5)genomes/µL with blood in situ. The application of WDM for rapid, automated detection of bacterial DNA from whole blood may have an enormous impact on the clinical diagnosis of infections in bloodstream or chronic wound/ulcer, and patient safety and morbidity.

Simeprevir for the treatment of chronic hepatitis C.

INTRODUCTION: The addition of protease inhibitors such as telaprevir and boceprevir with PEGylated interferon and ribavirin has significantly improved cure rates for genotype 1 hepatitis C virus (HCV) infection. Simeprevir (TMC435) is a second-generation protease inhibitor that is in development for the treatment of genotype 1 HCV infection. AREAS COVERED: The authors present: i) an overview of Phases I - III clinical trials of simeprevir for HCV infection based on peer-reviewed literature and congress presentations and ii) an evaluation of the efficacy and safety of simeprevir in the treatment of HCV infection. EXPERT OPINION: Simeprevir is a once-daily oral medication that combined with PEGylated interferon and ribavirin appears to be a potent and safe agent to treat genotype 1 HCV infection for patients who are treatment-naïve and prior treatment-failures. Compared to telaprevir and boceprevir, simeprevir will likely be the protease inhibitor of choice for genotype 1 HCV infection based on ease of use, lower rates of adverse events, including rash and anemia, and no significant reported drug-drug interactions. Associated side effects inherent with interferon-based regimens may be problematic for patients. As HCV therapies evolve into interferon-free regimens, simeprevir may potentially be combined with other oral direct-acting agents without interferon to treat HCV infection.

Life-threatening hypokalemia following rapid correction of respiratory acidosis.

A 56-year-old woman with a history of paraplegia and chronic pain due to neuromyelitis optica (Devic's syndrome) was admitted to a spinal cord injury unit for management of a sacral decubitus ulcer. During the hospitalization, she required emergency transfer to the intensive care unit (ICU) because of progressive deterioration of respiratory muscle function, severe respiratory acidosis, obtundation and hypotension. Upon transfer to the ICU, arterial blood gas revealed severe acute-on-chronic respiratory acidosis (pH 7.00, PCO2 120 mm Hg, PO2 211 mm Hg). The patient was immediately intubated and mechanically ventilated. Intravenous fluid boluses of normal saline (10.5 L in about 24 h) and vasopressors were started with rapid correction of hypotension. In addition, she was given hydrocortisone. Within 40 min of initiation of mechanical ventilation, there was improvement in acute respiratory acidosis. Sixteen hours later, however, the patient developed life-threatening hypokalemia (K(+) of 2.1 mEq/L) and hypomagnesemia (Mg of 1.4 mg/dL). Despite aggressive potassium supplementation, hypokalemia continued to worsen over the next several hours (K(+) of 1.7 mEq/L). Urine studies revealed renal potassium wasting. We reason that the recalcitrant life-threatening hypokalemia was caused by several mechanisms including total body potassium depletion (chronic respiratory acidosis), a shift of potassium from the extracellular to intracellular space (rapid correction of respiratory acidosis with mechanical ventilation), increased sodium delivery to the distal nephron (normal saline resuscitation), hyperaldosteronism (secondary to hypotension plus administration of hydrocortisone) and hypomagnesemia. We conclude that rapid correction of respiratory acidosis, especially in the setting of hypotension, can lead to life-threatening hypokalemia. Serum potassium levels must be monitored closely in these patients, as failure to do so can lead to potentially lethal consequences.

Shear- vs. nanotopography-guided control of growth of endothelial cells on RGD-nanoparticle-nanowell arrays.

Endothelialization of therapeutic cardiovascular implants is essential for their intravascular hemocompatibility. We previously described a novel nanowell-RGD-nanoparticle ensemble, which when applied to surfaces led to enhanced endothelialization and retention under static conditions and low flow rates. In the present study we extend our work to determine the interrelated effects of flow rate and the orientation of ensemble-decorated surface arrays on the growth, adhesion and morphology of endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were grown on array surfaces with either 1 µm × 5 µm spacing ("parallel to flow") and 5 µm × 1 µm spacing ("perpendicular to flow") and were exposed to a range of shear stress of (0 to 4.7 ± 0.2 dyn·cm-2 ), utilizing a pulsatile flow chamber. Under physiological flow (4.7 ± 0.2 dyn·cm-2), RGD-nanoparticle-nanowell array patterning significantly enhanced cell adhesion and spreading compared with control surfaces and with static conditions. Furthermore, improved adhesion coincided with higher alignment to surface patterning, intimating the importance of interaction and response to the array surface as a means of resisting flow detachment. Under sub-physiological condition (1.7 ± 0.3 dyn·cm-2; corresponding to early angiogenesis), nanowell-nanoparticle patterning did not provide enhanced cell growth and adhesion compared with control surfaces. However, it revealed increased alignment along the direction of flow, rather than the direction of the pattern, thus potentially indicating a threshold for cell guidance and related retention. These results could provide a cue for controlling cell growth and alignment under varying physiological conditions.

Single-pipetting microfluidic assay device for rapid detection of Salmonella from poultry package.

A direct, sensitive, near-real-time, handheld optical immunoassay device was developed to detect Salmonella typhimurium in the naturally occurring liquid from fresh poultry packages (hereafter "chicken matrix"), with just single pipetting of sample (i.e., no filtration, culturing and/or isolation, thus reducing the assay time and the error associated with them). Carboxylated, polystyrene microparticles were covalently conjugated with anti-Salmonella, and the immunoagglutination due to the presence of Salmonella was detected by reading the Mie scatter signals from the microfluidic channels using a handheld device. The presence of chicken matrix did not affect the light scatter signal, since the optical parameters (particle size d, wavelength of incident light λ and scatter angle θ) were optimized to minimize the effect of sample matrix (animal tissues and blood proteins, etc.). The sample was loaded into a microfluidic chip that was split into two channels, one pre-loaded with vacuum-dried, antibody-conjugated particles and the other with vacuum-dried, bovine serum albumin-conjugated particles. This eliminated the need for a separate negative control, effectively minimizing chip-to-chip and sample-to-sample variations. Particles and the sample were diffused in-channel through chemical agitation by Tween 80, also vacuum-dried within the microchannels. Sequential mixing of the sample to the reagents under a strict laminar flow condition synergistically improved the reproducibility and linearity of the assay. In addition, dried particles were shown to successfully detect lower Salmonella concentrations for up to 8 weeks. The handheld device contains simplified circuitry eliminating unnecessary adjustment stages, providing a stable signal, thus maximizing sensitivity. Total assay time was 10 min, and the detection limit 10 CFU mL(-1) was observed in all matrices, demonstrating the suitability of this device for field assays.

Cell-phone-based measurement of TSH using Mie scatter optimized lateral flow assays.

Semi-quantitative thyr oid stimulating hormone (TSH) lateral flow immunochromatographic assays (LFA) are used to screen for serum TSH concentration >5 mIUL(-1) (hypothyroidism). The LFA format, however, is unable to measure TSH in the normal range or detect suppressed levels of TSH (<0.4 mIU L(-1); hyperthyroidism). In fact, it does not provide quantitative TSH values at all. Obtaining quantitative TSH results, especially in the low concentration range, has until now required the use of centralized clinical laboratories which require specimen transport, specialized equipment and personnel, and result in increased cost and delays in the timely reporting of important clinical results. We have conducted a series of experiments to develop and validate an optical system and image analysis algorithm based upon a cell phone platform. It is able to provide point-of-care quantitative TSH results with a high level of sensitivity and reproducibility comparable to that of a clinical laboratory-based third-generation TSH immunoassay. Our research approach uses the methodology of the optimized Rayleigh/Mie scatter detection by taking into consideration the optical characteristics of a nitrocellulose membrane and gold nanoparticles on an LFA for quantifying TSH levels. Using a miniature spectrometer, LED light source, and optical fibers on a rotating benchtop apparatus, the light intensity from different angles of incident light and angles of detection to the LFA were measured. The optimum angles were found that the minimized Mie scattering from nitrocellulose membrane, consequently maximizes the Rayleigh scatter detection from the gold nanoparticles in the LFA bands. Using the results from the benchtop apparatus, a cell-phone-based apparatus was designed which utilized the embedded flash in the cell phone camera as the light source, piped the light with an optical fiber from the flash through a collimating lens to illuminate the LFA. Quantification of TSH was performed in an iOS application directly on the phone and verified using the code written in MATLAB. The limit of detection of the system was determined to be 0.31 mIU L(-1) (never achieved before on an LFA format), below the commonly accepted minimum concentration of 0.4 mIU L(-1) indicating clinical significance of hyperthyroidism. The system was further evaluated using human serum showing an accurate and reproducible platform for rapid and point-of-care quantification of TSH using a cell phone.

Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations.

A computer numerical control (CNC) apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using "wire-guided" method (a pipette tip was used in this study). This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging of droplets, simple DNA extraction utilizing the hydrophobicity difference between the tip and the superhydrophobic surface, and rapid thermocycling with a moving droplet, all with wire-guided droplet manipulations on a superhydrophobic surface and a multi-chambered PCB heater (i.e., not on a 96-well plate). Serial dilutions were demonstrated for diluting sample matrix. Centrifuging was demonstrated by rotating a 10 µL droplet at 2300 round per minute, concentrating E. coli by more than 3-fold within 3 min. DNA extraction was demonstrated from E. coli sample utilizing the disposable pipette tip to cleverly attract the extracted DNA from the droplet residing on a superhydrophobic surface, which took less than 10 min. Following extraction, the 1500 bp sequence of Peptidase D from E. coli was amplified using rapid droplet thermocycling, which took 10 min for 30 cycles. The total assay time was 23 min, including droplet centrifugation, droplet DNA extraction and rapid droplet thermocycling. Evaporation from of 10 µL droplets was not significant during these procedures, since the longest time exposure to air and the vibrations was less than 5 min (during DNA extraction). The results of these sequentially executed processes were analyzed using gel electrophoresis. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability), in rapid succession (using droplets), and with a high level of accuracy and automation.

Cytomegalovirus infection and the gastrointestinal tract.

Cytomegalovirus (CMV) infection is common worldwide, but the majority are asymptomatic. However, during initial infection or reactivation, CMV can cause tissue-invasive end-organ damage including in the gastrointestinal tract, especially in immunocompromised individuals. Gastrointestinal CMV disease can present with myriad of symptoms and be highly variable endoscopically. In this article we review the manifestations of CMV infection within the luminal gastrointestinal tract and discuss the options for diagnosis and management.

Direct and sensitive detection of foodborne pathogens within fresh produce samples using a field-deployable handheld device.

Direct and sensitive detection of foodborne pathogens from fresh produce samples was accomplished using a handheld lab-on-a-chip device, requiring little to no sample processing and enrichment steps for a near-real-time detection and truly field-deployable device. The detection of Escherichia coli K12 and O157:H7 in iceberg lettuce was achieved utilizing optimized Mie light scatter parameters with a latex particle immunoagglutination assay. The system exhibited good sensitivity, with a limit of detection of 10 CFU mL(-1) and an assay time of <6 min. Minimal pretreatment with no detrimental effects on assay sensitivity and reproducibility was accomplished with a simple and cost-effective KimWipes filter and disposable syringe. Mie simulations were used to determine the optimal parameters (particle size d, wavelength λ, and scatter angle θ) for the assay that maximize light scatter intensity of agglutinated latex microparticles and minimize light scatter intensity of the tissue fragments of iceberg lettuce, which were experimentally validated. This introduces a powerful method for detecting foodborne pathogens in fresh produce and other potential sample matrices. The integration of a multi-channel microfluidic chip allowed for differential detection of the agglutinated particles in the presence of the antigen, revealing a true field-deployable detection system with decreased assay time and improved robustness over comparable benchtop systems. Additionally, two sample preparation methods were evaluated through simulated field studies based on overall sensitivity, protocol complexity, and assay time. Preparation of the plant tissue sample by grinding resulted in a two-fold improvement in scatter intensity over washing, accompanied with a significant increase in assay time: ∼5 min (grinding) versus ∼1 min (washing). Specificity studies demonstrated binding of E. coli O157:H7 EDL933 to only O157:H7 antibody conjugated particles, with no cross-reactivity to K12. This suggests the adaptability of the system for use with a wide variety of pathogens, and the potential to detect in a variety of biological matrices with little to no sample pretreatment.

Very quick reverse transcription polymerase chain reaction for detecting 2009 H1N1 influenza A using wire-guide droplet manipulationst.

Reverse transcription polymerase chain reaction (RT-PCR) is currently a gold standard in identifying influenza A virus, especially H1N1 flu. Typical RT-PCR assays take about 1-2 h for thermocycling, and there is a growing need to further speed up the thermocycling to less than 30 min. Additionally, the PCR assay system should be made portable as a point-of-care detection tool. There have been attempts to further speed up the PCR assays by reducing its volume. There have also been attempts to use droplet microfluidics technology to PCR, primarily to automate the PCR enrichment processes and take advantage of its small volume. In all these attempts, heating and cooling is made by conduction heat transfer. Rapid movements of droplets (immersed in oil) over three different temperature zones make very quick PCR possible, as heating/cooling will be made by convection heat transfer, whose heat transfer coefficients are much higher than that of conduction. We used our newly-invented method of wire-guide droplet manipulations towards very quick RT-PCR. Computational fluid dynamics (CFD) simulation of our system revealed that heating/cooling for each temperature change takes 1-4 s for a 10 microL droplet, as compared to >30 s in the other quick PCRs. Theoretically a 30-cycle process can take as short as 13 s x 30 cycles = 6 min 30 s. The entire system was made as a single instrument, with the components made by a milling machine and a rapid prototyping device. No additional equipment and external computers are required. With this newly developed system, 160 bp gene sequence was amplified from 2009 H1N1 influenza A (human origin). The 30-cycle process took as short as 6 min 50 s for a 10 microL droplet (with additional 4 min for reverse transcription). Its product was confirmed by traditional gel electrophoresis, subsequent imaging as well as gene sequencing, which has been very difficult with the other stationary droplet/nanodrop approaches. The proposed system has a potential to become an extremely rapid, portable, point-of-care tool for detecting influenza A.

Diversity and clinical impact of Acinetobacter baumannii colonization and infection at a military medical center.

The epidemiology of Acinetobacter baumannii emerging in combat casualties is poorly understood. We analyzed 65 (54 nonreplicate) Acinetobacter isolates from 48 patients (46 hospitalized and 2 outpatient trainees entering the military) from October 2004 to October 2005 for genotypic similarities, time-space relatedness, and antibiotic susceptibility. Clinical and surveillance cultures were compared by amplified fragment length polymorphism (AFLP) genomic fingerprinting to each other and to strains of a reference database. Antibiotic susceptibility was determined, and multiplex PCR was performed for OXA-23-like, -24-like, -51-like, and -58-like carbapenemases. Records were reviewed for overlapping hospital stays of the most frequent genotypes, and risk ratios were calculated for any association of genotype with severity of Acute Physiology and Chronic Health Evaluation II (APACHE II) score or injury severity score (ISS) and previous antibiotic use. Nineteen genotypes were identified; two predominated, one consistent with an emerging novel international clone and the other unique to our database. Both predominant genotypes were carbapenem resistant, were present at another hospital before patients' admission to our facility, and were associated with higher APACHE II scores, higher ISSs, and previous carbapenem antibiotics in comparison with other genotypes. One predominated in wound and respiratory isolates, and the other predominated in wound and skin surveillance samples. Several other genotypes were identified as European clones I to III. Acinetobacter genotypes from recruits upon entry to the military, unlike those in hospitalized patients, did not include carbapenem-resistant genotypes. Acinetobacter species isolated from battlefield casualties are diverse, including genotypes belonging to European clones I to III. Two carbapenem-resistant genotypes were epidemic, one of which appeared to belong to a novel international clone.

FRET detection of Octamer-4 on a protein nanoarray made by size-dependent self-assembly.

An alternative approach for fabricating a protein array at nanoscale is suggested with a capability of characterization and/or localization of multiple components on a nanoarray. Fluorescent micro- and nanobeads each conjugated with different antibodies are assembled by size-dependent self-assembly (SDSA) onto nanometer wells that were created on a polymethyl methacrylate (PMMA) substrate by electron beam lithography (EBL). Antibody-conjugated beads of different diameters are added serially and electrostatically attached to corresponding wells through electrostatic attraction between the charged beads (confirmed by zeta potential analysis) and exposed p-doped silicon substrate underneath the PMMA layer. This SDSA method is enhanced by vibrated-wire-guide manipulation of droplets on the PMMA surface containing nanometer wells. Saturation rates of antibody-conjugated beads to the nanometer patterns are up to 97% under one component and 58-70% under two components nanoarrays. High-density arrays (up to 40,000 wells) could be fabricated, which can also be multi-component. Target detection utilizes fluorescence resonance energy transfer (FRET) from fluorescent beads to fluorescent-tagged secondary antibodies to Octamer-4 (Oct4), which eliminates the need for multiple steps of rinsing. The 100 nm green beads are covalently conjugated with anti-Oct4 to capture Oct4 peptides (39 kDa); where the secondary anti-Oct4 and F(ab)(2) fragment of anti-gIgG tagged with phycoerythrin are then added to function as an indicator of Oct4 detection. FRET signals are detected through confocal microscopes, and further confirmed by Fluorolog3 spectrofluorometer. The success rates of detecting Oct4 are 32% and 14% of the beads in right place under one and two component nanoarrays, respectively. Ratiometric FRET is used to quantify the amount of Oct4 peptides per each bead, which is estimated about 2 molecules per bead.

Backscattering particle immunoassays in wire-guide droplet manipulations.

A simpler way for manipulating droplets on a flat surface was demonstrated, eliminating the complications in the existing methods of open-surface digital microfluidics. Programmed and motorized movements of 10 muL droplets were demonstrated using stepper motors and microcontrollers, including merging, complicated movement along the programmed path, and rapid mixing. Latex immunoagglutination assays for mouse immunoglobulin G, bovine viral diarrhea virus and Escherichia coli were demonstrated by merging two droplets on a superhydrophobic surface (contact angle = 155 +/- 2 degrees ) and using subsequent back light scattering detection, with detection limits of 50 pg mL-1, 2.5 TCID50 mL-1 and 85 CFU mL-1, respectively, all significantly lower than the other immunoassay demonstrations in conventional microfluidics (~1 ng mL-1 for proteins, ~100 TCID50 mL-1 for viruses and ~100 CFU mL-1 for bacteria). Advantages of this system over conventional microfluidics or microwell plate assays include: (1) minimized biofouling and repeated use (>100 times) of a platform; (2) possibility of nanoliter droplet manipulation; (3) reprogrammability with a computer or a game pad interface.