Surgical Outcomes in Charcot Arthropathy.

Treatment of Charcot neuroarthropathy (CN) of the foot and ankle remains challenging for both patients and surgeons. Nonoperative treatment with cast/orthosis immobilization has long been the mainstay of treatment, but surgical intervention has gained interest to improve poor long-term outcomes. A review of existing data on the operative management of CN demonstrates the potential benefits but also the continued risks associated with treatment. Additionally, a retrospective review of cohorts managed with limited surgical interventions (wound debridements, exostectomies, and other surgical procedures) compared to reconstructive procedures provides additional insight into the surgical management of CN.

Deletion of PTP4A3 phosphatase in high grade serous ovarian cancer cells decreases tumorigenicity and produces marked changes in intracellular signaling pathways and cytokine release.

The oncogenic protein tyrosine phosphatase PTP4A3 is frequently overexpressed in human ovarian cancers and is associated with poor patient prognosis. PTP4A3 is thought to regulate multiple oncogenic signaling pathways, including STAT3, SRC, and ERK. The objective of this study was to generate ovarian cancer cells with genetically depleted PTP4A3; to assess their tumorigenicity; to examine their cellular phenotype; and to uncover changes in their intracellular signaling pathways and cytokine release profiles. Genetic deletion of PTP4A3 using CRISPR/Cas9 enabled the generation of individual clones derived from single cells isolated from the polyclonal knockout population. We observed a >90% depletion of PTP4A3 protein levels by Western blotting in the clonal cell lines compared to the sham transfected wildtype population. The wildtype and polyclonal knockout cell lines shared similar monolayer growth rates, while the isolated clonal populations 2B4, 3C9, and 3C12 exhibited significantly lower monolayer growth characteristics consistent with their lower PTP4A3 levels. The clonal PTP4A3 knockout cell lines also had substantially lower in vitro colony formation efficiencies compared to the wildtype cells and were less tumorigenic in vivo The clonal knockout cells were markedly less responsive to IL-6-stimulated migration in a scratch wound assay compared to the wildtype cells. Antibody microarray assays documented differences in cytokine release and intracellular phosphorylation patterns in the PTP4A3 deleted clones. Bioinformatic network analyses indicated alterations in cellular signaling nodes. These biochemical changes could ultimately form the foundation for pharmacodynamic endpoints useful for emerging anti-PTP4A3 therapeutics. Significance Statement Clones of high grade serous ovarian cancer cells were isolated in which the oncogenic phosphatase PTP4A3 was deleted using CRISPR/Cas9 methodologies. The PTP4A3 null cells exhibited loss of in vitro proliferation, colony formation, and migration, and reduced in vivo tumorigenesis. Marked differences in intracellular protein phosphorylation and cytokine release were seen. The newly developed PTP4A3 knockout cells should provide useful tools to probe the role of PTP4A3 phosphatase in ovarian cancer cell survival, tumorigenicity and cell signaling.

Pharmacological profiling identifies divergent chemosensitivities of differentiating and maturing iPSC-derived human cortical neuron populations.

Neuronal differentiation and maturation are extended developmental processes. To determine whether neurons at different developmental stages have divergent chemosensitivities, we screened differentiating and maturing neuronal populations using a small compound library comprising FDA-approved and investigational drugs. Using a neurotoxicity assay format, both respective neuronal population-based screening campaigns performed robustly (Z-factors = 0.7-0.8), although the hit rate for the differentiating neurons (2.8%) was slightly higher than for maturing neurons (1.9%). While the majority of hits were toxic to both neuronal populations, these hits predominantly represented promiscuous drugs. Other drugs were selectively neurotoxic, with receptor tyrosine kinase inhibitors disproportionally represented after confirmation. Ponatinib and amuvatinib were neuroinhibitory for differentiating and maturing neurons, respectively. Chemoinformatic analyses confirmed differences in potential drug targets that may be differentially expressed during neuronal development. Subsequent studies demonstrated neuronal expression of AXL, an amuvatinib target, in both neuronal populations. However, functional AXL activity was confirmed only in the maturing neuronal population as determined by AXL phosphorylation in response to GAS6, the cognate ligand of AXL, and concurrent STAT3Y705 phosphorylation. Differentiating neurons were unresponsive to the effects of GAS6 suggesting that the AXL-STAT3 signaling axis was nonfunctional. Amuvatinib treatment of maturing neuronal cultures significantly reduced pAXL levels. These studies indicate that neuronal developmental states may exhibit unique chemosensitivities and that drugs may have different neuro-inhibitory effects depending upon the developmental stage of the neuronal population.

Social Isolation in Community-Dwelling Older Adults During COVID-19: Understanding the Role of Resilience.

The COVID-19 pandemic increased social isolation for many older adults, causing concern for their health and well-being. To enhance understanding of how community-dwelling older adults were impacted by prolonged social isolation during COVID-19, a qualitative descriptive study was conducted to: (1) explore the self-reported factors supporting their resilience during COVID-19 related social isolation, and (2) to help understand the intentional and unintentional outcomes of the government mandated health measures. A total of 19 community dwelling older adults were sampled. Factors that supported older adults' resilience during COVID-19 included maintaining positivity, drawing on historical experiences of resilience and finding opportunities to connect with their community. However, collective safety came with losses: such as time, freedom, opportunity, engagement, and initiative. The findings provide insight on contributing factors to resilience against social isolation in older adults and suggest the value of collective, community-based approaches to build resilience across variable contexts in this population.

High content screening miniaturization and single cell imaging of mature human feeder layer-free iPSC-derived neurons.

Human induced pluripotent stem cell (iPSC)-derived neurons are being increasingly used for high content imaging and screening. However, iPSC-derived neuronal differentiation and maturation is time-intensive, often requiring >8 weeks. Unfortunately, the differentiating and maturing iPSC-derived neuronal cultures also tend to migrate and coalesce into ganglion-like clusters making single-cell analysis challenging, especially in miniaturized formats. Using our defined extracellular matrix and low oxygen culturing conditions for the differentiation and maturation of human cortical neurons, we further modified neuronal progenitor cell seeding densities and feeder layer-free culturing conditions in miniaturized formats (i.e., 96 well) to decrease neuronal clustering, enhance single-cell identification and reduce edge effects usually observed after extended neuronal cell culture. Subsequent algorithm development refined capabilities to distinguish and identify single mature neurons, as identified by NeuN expression, from large cellular aggregates, which were excluded from image analysis. Incorporation of astrocyte conditioned medium during differentiation and maturation periods significantly increased the percentage (i.e., ∼10% to ∼30%) of mature neurons (i.e., NeuN+) detected at 4-weeks post-differentiation. Pilot, proof of concept studies using this optimized assay system yielded negligible edge effects and robust Z-factors in population-based as well as image-based neurotoxicity assay formats. Moreover, moxidectin, an FDA-approved drug with documented neurotoxic adverse effects, was identified as a hit using both screening formats. This miniaturized, feeder layer-free format and image analysis algorithm provides a foundational imaging and screening platform, which enables quantitative single-cell analysis of differentiated human neurons.

Inadvertent triggering of the ventilator caused by surgically placed pacer wires.

Inadvertent ventilator triggering can occur for various reasons. Leaks in the ventilator circuit, endotracheal tube leaks, tracheal cuff leaks, cardiac oscillations, water condensate causing oscillations in the circuit tubing, ventilator expiratory valve integrity, and overly sensitive triggering mechanism settings may precipitate this phenomena. We present a case of inadvertent ventilator triggering caused by electrical stimulation of the diaphragm from surgically placed pacing wires post cardiothoracic surgery. A 47-year-old woman underwent surgical placement of a left (LVAD) and right (RVAD) ventricular assist device for severe end stage cardiomyopathy, as a bridge to cardiac transplantation. The patient was observed to have inadvertent ventilator triggering while deeply sedated postoperatively. The ventilator set respiratory rate was 16 breaths/min, with patient respiratory rate of 30 breaths/min while deeply sedated. Upon assessment of ventilator waveforms and arterial blood gas revealing a profound respiratory alkalosis, the pressure/time waveform demonstrated a -2 cm H(2)O decrease in pressure prior to each cycled breath. The ventilator was subsequently changed from flow trigger sensitivity of 3 L/min to pressure trigger sensitivity of -3 cm H(2)O to eliminate the autotriggering. Later in the patient's ICU stay, inadvertent ventilator triggering was again observed. Further adjustment of the pressure trigger sensitivity to -3 cm H(2)O eliminated the autotriggering. Clinical assessment found the pacing wires were responsible for stimulating the patient's diaphragm, therefore causing airway pressure decreases and premature breath delivery. Once the electrical amplitude of the pacemaker was decreased, the inadvertent ventilator triggering resolved and normal trigger sensitivity and pH was restored.

Platypnea-orthodeoxia related to aortic elongation.

An 80-year-old woman presented with progressive shortness of breath. There was no history of pulmonary or cardiac disease. Results of a physical examination were normal. She had significant oxygen desaturation while she was in an upright position. Admission to the hospital for workup followed, and evaluation included tilt-table transesophageal echocardiogram and cardiac catheterization. A massive right-to-left shunt through a patent foramen ovale was detected, and surgical intervention resulted in dramatic improvement of symptoms. In this patient, it seems that the syndrome of platypnea-orthodeoxia was related to aortic elongation, allowing significant right-to-left shunt.

Percutaneous absorption of benzyl acetate through rat skin in vitro. 3. A comparison with human skin.

The comparative absorption of the fragrance and industrial compound, benzyl acetate, has been studied in rat and human skin, using shaved, full-thickness dorsal skin of male Fischer 344 rats and full-thickness human skin obtained from patients undergoing surgical resection. Penetration of the compound through rat and human skin was evaluated in vitro in flow-through diffusion cells following topical application of neat [methylene-14C] benzyl acetate (33.1 mg/cm2) to the epidermal surface and occlusion with a teflon cap, 2.9 cm above the skin surface. The absorption of benzyl acetate across rat skin was rapid and extensive, reaching 34.3 +/- 3.9% of the applied dose (11.3 +/- 1.3 mg/cm2) (mean +/- SD, n = 12) at 24 hr and 55.8 +/- 5.0% of the applied dose (18.5 +/- 1.7 mg/cm2) at 72 hr. The penetration of benzyl acetate was significantly (P < 0.05) less rapid and extensive through human skin, reaching 5.5 +/- 0.1% of the applied dose (1.8 +/- 0.0 mg/cm2) (mean +/- SD, n = 12) at 24 hr and 17.8 +/- 3.3% of the applied dose (5.9 +/- 1.1 mg/cm2) at 72 hr. The rate of penetration of benzyl acetate was greater through rat skin than through human tissue at all time points studied up to 72 hr. The maximum rate of skin penetration was 0.6 +/- 0.1 mg/cm2/hr and 0.1 +/- 0.0 mg/cm2/hr through rat and human skin, respectively. These data indicate that systemic exposure to benzyl acetate may occur after skin contact in humans. They also support the evidence from the literature that human skin is generally less permeable to xenobiotics than rat skin.

Relationship between cardiac output and the end-tidal carbon dioxide tension.

STUDY OBJECTIVE: To further define the relationship between cardiac output (CO) and end-tidal carbon dioxide tension (ETCO2) at various levels of systemic flow. DESIGN: Prospective, controlled laboratory investigation. SETTING: Animal laboratory. TYPE OF PARTICIPANTS: Fourteen anesthetized, intubated sheep weighing 23 to 47 kg. INTERVENTIONS: One hundred seventy-two simultaneous measurements of thermodilution CO and ETCO2 were made during controlled arterial hemorrhage. After a 30-minute baseline control period, CO was sampled from approximately 0.6 to more than 8.0 L/min during a 60- to 90-minute period of controlled hemorrhage. MEASUREMENTS: Thermodilution CO; arterial pressure using fluid-filled plastic 14-gauge catheters; ETCO2 using an infrared analyzer. MAIN RESULTS: A plot of CO versus ETCO2 suggested that the relationship was logarithmic rather than linear. Linear regression showed that ETCO2 was significantly related (r = .91; P less than .001) to a logarithmic transformation of the CO. CONCLUSIONS: The relationship between CO and ETCO2 is logarithmic. Decreased presentation of CO2 to the lungs is the major, rate-limiting determinant of the ETCO2 during low flow. As the CO increases during resuscitation from shock or cardiac arrest, respiration becomes the rate-limiting controller of the ETCO2 (after the tissue washout of CO2 has occurred). Under such conditions, the ETCO2 provides useful information about the adequacy of ventilation provided that there is little ventilation/perfusion mismatch.

Dose-dependent vasopressor response to epinephrine during CPR in human beings.

The optimal dose of epinephrine during CPR in human beings is unknown. We studied ten prehospital cardiac arrest patients (six men and four women; mean age, 54 +/- 5 years) to determine the vasopressor response and change in the end-tidal carbon dioxide concentration (PetCO2) after incremental (1-, 3-, and 5-mg) doses of IV epinephrine given five minutes apart during closed-chest CPR. All patients were in ventricular fibrillation on arrival of the paramedics and did not respond to standard advanced cardiac life support. CPR was performed with a computerized Thumper; all patients were intubated and ventilated at 12 times a minute at an FiO2 of 0.8. Radial artery pressure was measured with a 20 angiocath inserted by radial artery cutdown. Paramedic response time was 4.3 +/- 0.5 minutes; elapsed time to emergency department arrival was 40.0 +/- 9.5 minutes. Initial blood gases were paO2, 241 +/- 50 mm Hg; pH, 7.23 +/- 0.08; paCO2, 27 +/- 5 mm Hg; and HCO3, 11 +/- 2 mEq/L. Baseline systolic and diastolic blood pressures were 47 +/- 5 mm Hg and 18 +/- 2 mm Hg, respectively. Systolic blood pressure was directly related to the dose of epinephrine (P less than .0001), rising to 69 +/- 7 mm Hg, 74 +/- 8 mm Hg, and 85 +/- 8 mm Hg after 1-, 3-, and 5-mg doses of epinephrine, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of applied chest compression force on systemic arterial pressure and end-tidal carbon dioxide concentration during CPR in human beings.

Twelve adult (nine men and three women) cardiac arrest patients were studied as they received CPR by a computerized Thumper to determine the influence of the applied chest compression force on blood flow (as assessed by the end-tidal carbon dioxide concentration) and arterial pressure. At the end of a resuscitation when the decision was made by the senior physician to cease resuscitative efforts, the applied force on the CPR Thumper was decreased from 140 to 0 pound-force (lbf) in 20-lbf increments at 30-second intervals. Radial artery cutdown blood pressure and end-tidal carbon dioxide (ETCO2) were recorded continuously. Arterial systolic blood pressure was linearly related (r = .59, P less than .0001) to applied force (systolic blood pressure, 31 +/- 6 mm Hg at 20 lbf to 60 +/- 7 mm Hg at 140 lbf). ETCO2 (r = .42, P less than .0001) was also linearly related to applied force (ETCO2, 0.7 +/- 0.1% at 20 lbf to 1.5 +/- 0.2% at 140 lbf). Diastolic pressure did not change significantly with change in applied force (17 +/- 2 mm Hg from 20 to 140 lbf). Our findings indicate that higher compression force than that currently recommended may improve arterial systolic pressure and flow in human beings receiving closed-chest compression during CPR.

Capnographic waveforms in esophageal intubation: effect of carbonated beverages.

Capnography is a useful tool in differentiating tracheal from esophageal intubation. It may be an especially useful tool in emergency airway management by rescue squads or in the emergency department. However, in clinical practice the question has arisen as to whether prior ingestion of carbonated beverages can generate false-positive capnographic evidence of endotracheal intubation when in fact esophageal intubation has occurred. To answer this question, we compared the difference between tracheal and esophageal capnographic waveforms in dogs in the setting of recent ingestion of carbonated beverages. Esophageal capnographic recordings from three of five dogs undergoing esophageal ventilation were strikingly positive for exhaled carbon dioxide; however, the waveforms were significantly different from waveforms of tracheal ventilation. We conclude that esophageal intubation, after recent ingestion of carbonated beverages, may give false-positive waveforms suggestive of tracheal intubation. Rapidly diminishing CO2 concentrations, however, help differentiate esophageal from tracheal ventilation in this setting.

Hypercarbic arterial acidemia following resuscitation from severe hemorrhagic shock.

Arteriovenous pH and PCO2 gradients can develop during low cardiac output states. We have seen a transient rise in arterial PCO2 and a fall in arterial pH in humans receiving closed-chest cardiopulmonary resuscitation immediately following restoration of spontaneous circulation. Using a hemorrhagic shock model in sheep, serial arterial and mixed venous blood gases were sampled and CO2 elimination was measured. When cardiac output was less than 30% of the baseline value and the arteriovenous PCO2 difference was greater than 20 mmHg, the animals were rapidly resuscitated with intravenous 0.9% NaCl and dopamine. Following resuscitation, there was a transient arterial acidosis and hypercarbia due to passage of venous blood with a high CO2 content into arterial blood. The clinical implications in the setting of hemorrhagic shock are that (1) arterial blood gases are poor indicators of the systemic acid-base state, (2) arterial blood gases drawn immediately following volume resuscitation may be misinterpreted and should probably not be used to guide therapy and (3) there is a transient hypercarbic arterial acidosis following volume resuscitation that may have deleterious effects on cardiac and cerebral function in the early post-resuscitative period.

Treatment of paroxysmal supraventricular tachycardia in the emergency department by clinical decision analysis.

Vagal maneuvers terminate new onset, catheter-induced paroxysmal supraventricular tachycardia (PSVT) in up to 92% of patients. The risk and benefit of vagal maneuvers for treating PSVT in the emergency department (ED) is inadequately defined. The purpose of this study was to determine the efficacy of nonpharmacological vagal interventions in converting spontaneous episodes of PSVT in adult patients and to derive a treatment plan for such patients based on clinical decision analysis. Seventeen adult patients who presented to the ED because of PSVT were treated with carotid sinus massage, Valsalva maneuver, and head-down tilt (alone and in combination). Only three patients converted out of PSVT with vagal intervention. The remainder received verapamil, which converted 12 of the 14 patients (86%) who received the drug (one required digoxin, one required synchronized cardioversion). Vagal maneuvers are safe in young, otherwise healthy patients but problems have been documented in the literature in older patients, who have a higher likelihood of coronary and/or cerebrovascular disease. Clinical decision analysis indicates that young patients should be treated initially with vagal maneuvers but that older patients (above approximately 65 years of age) should be treated initially with verapamil.

Effect of cardiopulmonary resuscitation compression rate on end-tidal carbon dioxide concentration and arterial pressure in man.

The optimal rate of chest compression during CPR in man has been debated. Recently, the end-tidal carbon dioxide concentration (PetCO2) has been shown to correlate with cardiac output during CPR in experimental animals. Eighteen prehospital cardiac arrest patients were studied to determine the effect of external chest compression rate on the PetCO2 and BP in man when ventilation rate, ventilation inspiration time, applied compression force, and a 50:50 downstroke:upstroke ratio were held constant using a microprocessor-controlled CPR Thumper. Compression rate was increased from 60 to 140/min in 20 beat/min increments. The PetCO2 was 1.7 +/- 0.2% at a compression rate of 60/min and did not change significantly at increased rates. Systolic BP fell progressively from 59 +/- 5 mm Hg at 60/min to 46 +/- 4 mm Hg at 140/min. Diastolic BP remained approximately 23 mm Hg at all rates studied. Using a CPR manikin, we found that greater Thumper compression force was necessary to sustain the same sternal displacement and to achieve the same applied sternal pressure when the rate was increased due to a rate-limited fall in the compression duration.

Cost-effectiveness of defibrillation by emergency medical technicians.

Effective emergency systems using emergency medical technicians (EMTs) trained to defibrillate or paramedics can save more lives from out-of-hospital cardiac arrest due to ventricular fibrillation than can emergency systems staffed with basic EMTs who cannot defibrillate. This article focuses on the cost-effectiveness of systems staffed with each type of EMT. Data were collected from all 50 states and from the District of Columbia to determine the number of hours and estimated cost of initial training for the three types of EMTs in the United States in 1986. The median initial training hours for basic EMTs, EMTs trained in defibrillation, and paramedics were 110, 129, and 700, respectively. Median costs for initial training at each EMT level were +123, +150, and +1580/student. According to published survival data for emergency medical systems staffed with EMTs at each level, the total initial training personnel and equipment cost per life saved from ventricular fibrillation was +7687, +2126, and +2289 for systems staffed by the respective EMTs. The initial cost per life saved from ventricular fibrillation is more than three times greater in systems staffed by basic EMTs than in systems staffed by EMTs trained in defibrillation or paramedics. From a medical and a cost-effective standpoint, all communities served by basic EMTs should consider upgrading them to at least the defibrillation-trained EMT level.

End-tidal carbon dioxide monitoring during cardiopulmonary resuscitation.

The end-tidal carbon dioxide (CO2) concentration has been found to correlate with cardiac output during and after cardiopulmonary resuscitation (CPR) in animal models. We monitored end-tidal CO2 values continuously during cardiac resuscitation in 23 humans while ventilation was held constant with a computer-controlled CPR Thumper. This report focuses on ten of the 23 patients who experienced return of spontaneous circulation (ROSC) during monitoring. There was no significant difference in the end-tidal CO2 value of patients without ROSC (1.8% +/- 0.9%) and the end-tidal CO2 value of patients before ROSC in patients who had ROSC (1.7% +/- 0.6%). The end-tidal CO2 concentration increased immediately in all patients who had ROSC, from 1.7% +/- 0.6% to 4.6% +/- 1.4%, then gradually returned to a new baseline (3.1% +/- 0.9%). Change in the end-tidal CO2 value was often the first clinical indicator that ROSC had occurred. Our findings suggest that end-tidal CO2 monitoring may provide clinically useful information that can be used to guide therapy during CPR.

Bacterial contamination of ambulance oxygen humidifier water reservoirs: a potential source of pulmonary infection.

The risk and benefit of oxygen humidification during ambulance transport is unknown. We cultured the water in plastic multiple-use bottles of humidifiers on 30 randomly selected area ambulances during November 1985. There were 22 positive cultures. Potentially pathogenic bacteria (four Pseudomonas maltophilia, three Pseudomonas aeruginosa, one Klebsiella pneumoniae, and one Staphylococcus epidermidis) were found in nine samples. Assuming that the water in ambulance humidifiers should have been sterile, the findings are statistically significant (P less than .01). Because there is no evidence that humidification is of benefit for nonintubated patients receiving oxygen at flow rates of 4 L/min or less when environmental humidity is adequate, we suggest that such patients should receive oxygen without humidification during ambulance transport. All other patients requiring oxygen during ambulance transport should continue to receive humidified oxygen. If a multiple-use humidifier reservoir is to be used, a written policy for its use must be developed and there must be appropriate documentation of compliance with the policy. An alternative is to replace the multiple-use humidifier reservoir with single-use sterile disposable devices, which cost approximately $2.00 per unit.

Gentamicin penetration and decay in the human aqueous.

The penetration of gentamicin into human aqueous was measured after intensive drops or subconjunctival injection of the antibiotic. The drop regimen proved ineffective in producing a therapeutically effective level. After a single 40 mg subconjunctival injection an effective concentration was achieved in 2 hours and maintained for 24 hours. The significance of these findings is discussed with respect to therapeutic implications.