Predictors of favorable outcome after pyloroplasty for gastroparesis: should response to pyloric dilation or Botox injection be used as a marker of surgical outcome?

INTRODUCTION: Pyloroplasty and gastric peroral endoscopic myotomy (G-POEM) are effective surgeries for gastroparesis. The primary aim of this study was to evaluate outcomes of pyloroplasty and G-POEM in patients with gastroparesis and determine factors associated with favorable outcome. The secondary aim was to assess the utility of clinical response to preoperative pyloric dilation or botulinum toxin injection (Botox) on surgical outcome, a factor conventionally used as a favorable marker. METHODS: There were 204 patients who underwent pyloroplasty (n = 177) or G-POEM (n = 27) for gastroparesis at our institution from 2014 to 2021. Demographic and clinical parameters were analyzed to assess their impact on surgical outcome. A subgroup of patients who had pyloric dilation or Botox injection were assessed separately. Favorable outcome was defined as patient reported complete resolution of the predominant gastroparesis symptom. RESULTS: Favorable outcome was achieved in 78.4% of patients (pyloroplasty: 79.7% and G-POEM: 70.4%, p = 0.274). Among 61 patients where pre- and postoperative gastric emptying studies (GES) were available, mean 4-hour retention significantly improved from 33.5 to 15.0% (p < 0.001) and 77.0% of patients achieved normalization. Favorable outcome was not significantly impacted by etiology of gastroparesis (p = 0.120), GERD (p = 0.518), or primary gastroparesis symptom (p = 0.244). Age ≥ 40 was a significant predictor of favorable surgical outcome on multivariate analysis [OR: 2.476 (1.224-5.008), p = 0.012]. Among the patients who had preoperative dilation (n = 82) or Botox injection (n = 46), response to these interventions was not a predictor of favorable surgical outcome (p = 0.192 and 0.979, respectively). However, preoperative Botox injection, regardless of response to injection, was associated with favorable surgical outcome [OR: 3.205 (CI 1.105-9.299), p = 0.032]. CONCLUSION: Symptomatic improvement after pyloroplasty or G-POEM is independent of etiology of gastroparesis, GERD, and primary symptom. Response to dilation or Botox are not markers of response to surgery. However, patients who receive Botox are 3.2 times more likely to improve postoperatively.

A unifying framework for analyzing temporal changes in functional and taxonomic diversity along disturbance gradients.

Frameworks exclusively considering functional diversity are gaining popularity, as they complement and extend the information provided by taxonomic diversity metrics, particularly in response to disturbance. Taxonomic diversity should be included in functional diversity frameworks to uncover the functional mechanisms causing species loss following disturbance events. We present and test a predictive framework that considers temporal functional and taxonomic diversity responses along disturbance gradients. Our proposed framework allows us to test different multidimensional metrics of taxonomic diversity that can be directly compared to calculated multidimensional functional diversity metrics. It builds on existing functional diversity-disturbance frameworks both by using a gradient approach and by jointly considering taxonomic and functional diversity. We used previously unpublished stream insect community data collected prior to, and for the two years following, an extreme flood event that occurred in 2013. Using 14 northern Colorado mountain streams, we tested our framework and determined that taxonomic diversity metrics calculated using multidimensional methods resulted in concordance between taxonomic and functional diversity responses. By considering functional and taxonomic diversity together and using a gradient approach, we were able to identify some of the mechanisms driving species losses following this extreme disturbance event.

Multifactorial dysphagia: Azygos vein aneurysm (AVA) and esophagogastric junction outflow obstruction (EGJOO).

INTRODUCTION: Vascular impingement of the esophagus is a rare cause of dysphagia, and is most commonly due to aortic arch anomalies such as arterial lusoria. Dysphagia resultant from venous compression is even further less likely. PRESENTATION OF CASE: We present a highly unusual case of dysphagia secondary to a large aneurysm of the azygous vein near its confluence with the superior vena cava, which was managed with endovascular modalities. Despite initial treatment success, patient reported some intermittent solid food dysphagia, and was also found to have esophagogastric junction outflow obstruction (EGJOO) on high resolution impedance manometry (HRIM) which was successfully managed with surgical myotomy and partial fundoplication. DISCUSSION: The azygos vein has an intimate anatomic relationship with the esophagus as it traverses the posterior mediastinum. Because of this anatomic association, the azygos vein may present a point of esophageal obstruction in the setting of significant pathology. CONCLUSION: This case highlights the possibility of multifactorial causes of dysphagia, and that HRIM is a key aspect of this workup. Additionally we discuss the pertinent anatomy, diagnosis, and treatments for azygos vein aneurysm and EGJOO.

The Molecular Basis of pH-Modulated HIV gp120 Binding Revealed.

Decades of research has yet to provide a vaccine for HIV, the virus which causes AIDS. Recent theoretical research has turned attention to mucosa pH levels over systemic pH levels. Previous research in this field developed a computational approach for determining pH sensitivity that indicated higher potential for transmission at mucosa pH levels present during intercourse. The process was extended to incorporate a principal component analysis (PCA)-based machine learning technique for classification of gp120 proteins against a known transmitted variant called Biomolecular Electro-Static Indexing (BESI). The original process has since been extended to the residue level by a process we termed Electrostatic Variance Masking (EVM) and used in conjunction with BESI to determine structural differences present among various subspecies across Clades A1 and C. Results indicate that structures outside of the core selected by EVM may be responsible for binding affinity observed in many other studies and that pH modulation of select substructures indicated by EVM may influence specific regions of the viral envelope protein (Env) involved in protein-protein interactions.

Extreme streams: species persistence and genomic change in montane insect populations across a flooding gradient.

The ecological and evolutionary consequences of extreme events are poorly understood. Here, we tested predictions about species persistence and population genomic change in aquatic insects in 14 Colorado mountain streams across a hydrological disturbance gradient caused by a one in 500-year rainfall event. Taxa persistence ranged from 39 to 77% across sites and declined with increasing disturbance in relation to species' resistance and resilience traits. For taxa with mobile larvae and terrestrial adult stages present at the time of the flood, average persistence was 84% compared to 25% for immobile taxa that lacked terrestrial adults. For two of six species analysed, genomic diversity (allelic richness) declined after the event. For one species it greatly expanded, suggesting resilience via re-colonisation from upstream populations. Thus, while resistance and resilience traits can explain species persistence to extreme disturbance, population genomic change varies among species, challenging generalisations about evolutionary responses to extreme events at landscape scales.

Wheelchair-mounted robotic arm to hold and move a communication device - final design.

At the 51st Rocky Mountain Bioengineering Symposium we presented a preliminary design for a robotic arm to assist an individual living within an assistive technology smart home. The individual controls much of their environment with a Dynavox Maestro communication device. However, the device obstructs the individual’s line of site when navigating about the smart home. A robotic arm was developed to move the communication device in and out of the user’s field of view as desired. The robotic arm is controlled by a conveniently mounted jelly switch. The jelly switch sends control signals to a four state (up, off, down, off) single-axis robotic arm interfaced to a DC motor by high power electronic relays. This paper describes the system, control circuitry, and multiple safety features. The arm will be delivered for use later in 2015.

Wrist/Arm support to assist in fine motor control for essential tremor patients.

Steady-state hand tremors tend to exhibit simple harmonic motion associated with frequencies of 2-11 Hz, and maximum amplitudes of 7.8 inches. Tremors often present difficulties in applications dependent on fine motor control. A wrist/arm constraint is being designed to minimize the difficulty of performing fine motor functions via amplitude and frequency reduction of the hand tremor. Tremor amplitude and frequency reduction can be achieved by utilizing mechanical dampers as well as viscoelastic materials to cradle the wrist and hand. The goal of this project is to design a mechanical, table-mounted wrist cradle with a damped natural frequency lower than the tremor frequency. This project is being designed for a specific person with tremor frequency of 5-6 Hz and peak-to-peak amplitude of 2.5 inches. These specifications will enable the user to touch a 1 inch by 1 inch icon on a touchscreen tablet device. The design team for this project consisted of senior Mechanical Engineering students from the University of Wyoming. Funding for this project is provided by NSF-BME-RAPD Grant 0962380.

Wheelchair-mounted robotic arm to hold and move communication device.

Some individuals with disabilities who use wheelchairs utilize communication devices to control their environment. Such devices are typically mounted on a fixed arm in a manner that obstructs the line of sight of a user when navigating the wheelchair. Some individuals with disabilities who utilize wheelchairs have limited or no control of arm or head movement. Design of a user-controlled robotic arm which moves the communication device in and out of the user’s line of sight would enable navigation of the wheelchair without removal of the communication device. Such a robotic device will be controlled by a push-button jelly switch. Positioning of this activation device will be located behind the user’s left elbow. Design of a single-axis, rotary robotic arm to be installed on a Quantum Q6 Edge wheelchair is ongoing, and will be completed by February 2014. A working prototype will be completed before April 2014. It is expected that upon completion of the robotic arm, the device will successfully move an 8 lb. Dynavox Maestro communication device in and out of a user’s line of sight by single-switch activation initiated by a user. The design presented in this report is patent pending.

Hydrolytic synthesis and structural characterization of lanthanide-acetylacetonato/hydroxo cluster complexes--a systematic study.

Lanthanide hydroxide cluster complexes with acetylacetonate were synthesized by the hydrolysis of the corresponding hydrated lanthanide acetylacetonates in methanol in the presence of triethylamine. Polymeric lanthanide hydroxide complexes based on diamond-shaped dinuclear repeating units of [Ln(2)(CH(3)CO(3))(2)](4+) (Ln = La, Pr) and discrete complexes featuring a tetranuclear distorted cubane core of [Ln(4)(µ(3)-OH)(2)(µ(3)-OCH(3))(2)](8+) (Ln = Nd, Sm) and a nonanuclear core of [Ln(9)(µ(4)-O)(µ(4)-OH)(µ(3)-OH)(8)](16+) (Ln = Eu-Dy, Er, Yb) were obtained. The dependence of the cluster nuclearity on the identity of the lanthanide ion is rationalized in terms of the influences of a metal ion's Lewis acidity and the sterics about the Ln-OH unit on the kinetics of the assembly process that leads to a particular cluster.

Undergraduate design projects to aid persons with disabilities: reflections.

In Spring 2002 the University of Wyoming, College of Engineering, received a five year grant from the National Science Foundation to link senior capstone design projects with the custom requirements of the assistive technology (AT) community. This serendipitous collaboration has been highly beneficial to our senior design students as well as individuals with a disability requiring one-of-a-kind AT devices. Now that the program is coming to a close on its five year term, we believe there are lessons we have learned that would be valuable to others considering participation in such a program. We will briefly review program development and organization, highlight lessons learned, and discuss program benefits and pitfalls. Paper emphasis will be on the practical implementation and management of this valuable program. Due to the rich benefits received from participating in the program, we plan on applying for a second five year program funding increment.