Clinicodemographic Predictors of Tracheotomy Tube Size and Decannulation: A Multiinstitutional Retrospective Cohort Study on Tracheotomy.

OBJECTIVE: We aimed to discern clinico-demographic predictors of large (≥8) tracheostomy tube size placement, and, secondarily, to assess the effect of large tracheostomy tube size and other parameters on odds of decannulation before hospital discharge. SUMMARY OF BACKGROUND DATA: Factors determining choice of tracheostomy tube size are not well-characterized in the current literature, despite evidence linking large tracheostomy tube size with posttracheotomy tracheal stenosis. The effect of tracheostomy tube size on timing of decannulation is also unknown, an important consideration given reported associations between endotracheal tube size and probability of failed extubation. METHODS: We collected information pertaining to patients who underwent tracheotomy at 1 of 10 U.S. health care institutions between 2010 and 2019. Tracheostomy tube size was dichotomized (≥8 and <8). Multivariable logistic regression models were fit to identify predictors of (1) large tracheostomy tube size, and (2) decannulation before hospital discharge. RESULTS: The study included 5307 patients, including 2797 (52.7%) in the large tracheostomy cohort. Patient height (odds ratio [OR] = 1.060 per inch; 95% confidence interval [CI] 1.041-1.070) and obesity (1.37; 95% CI 1.1891.579) were associated with greater odds of large tracheostomy tube; otolaryngology performing the tracheotomy was associated with significantly lower odds of large tracheostomy tube (OR = 0.155; 95% CI 0.131-0.184). Large tracheostomy tube size (OR = 1.036; 95% CI 0.885-1.213) did not affect odds of decannulation. CONCLUSIONS: Obesity was linked with increased likelihood of large tracheostomy tube size, independent of patient height. Probability of decannulation before hospital discharge is influenced by multiple patient-centric factors, but not by size of tracheostomy tube.

Accuracy of Ultrasound Imaging for Etiology of New-Onset Painless Jaundice.

PURPOSE: Ultrasound (US) is considered a first-line study for painless jaundice. However, in our hospital system, patients with new-onset painless jaundice often have a contrast-enhanced computed tomography (CECT) or magnetic resonance cholangiopancreatography (MRCP) regardless of the sonographic findings. Thus, we investigated the accuracy of US for detection of biliary dilatation in patients with new-onset painless jaundice. METHODS: Our electronic medical record was searched from January 1, 2012, to January 1, 2020, for adult patients with new-onset painless jaundice. Presenting complaint/setting, laboratory values, imaging studies/findings, and final diagnoses were recorded. Patients with pain or known liver disease were excluded. A gastrointestinal physician reviewed the laboratory values/chart to classify the type of suspected obstruction. Two radiologists blindly re-reviewed the US scans, and κ between the radiologists was calculated. Fisher exact test and the 2-sample t test were used for statistical analysis. RESULTS: Three hundred sixty patients presented with jaundice (>3 mg/dL), of whom 68 met the inclusion criteria (no pain and no known liver disease). Laboratory values had an overall accuracy of 54%, but were accurate in 87.5% and 85% for obstructing stones/pancreaticobiliary cancer. Ultrasound demonstrated overall accuracy of 78%, but only 69% for pancreaticobiliary cancer and 12.5% for common bile duct stone. Seventy-five percent of the patients underwent follow-up CECT or MRCP regardless of presenting setting. In the emergency department or inpatient setting, 92% of the patients underwent CECT or MRCP regardless of US, and 81% had follow-up CECT or MRCP within 24 hours. CONCLUSION: A US-first strategy in the setting of new-onset painless jaundice is accurate only 78% of the time. In practice, US was almost never a stand-alone imaging examination in patients presenting to the emergency department or inpatient setting with new-onset painless jaundice, no matter the suspected diagnosis based on clinical and laboratory grounds or on the US findings themselves. However, for milder elevations of unconjugated bilirubin (suspicious for Gilbert disease) in the outpatient setting, a US demonstrating lack of biliary dilatation was often a definitive study for exclusion of pathology.

T-Cell Mediation of Pregnancy Analgesia Affecting Chronic Pain in Mice.

It has been reported consistently that many female chronic pain sufferers have an attenuation of symptoms during pregnancy. Rats display increased pain tolerance during pregnancy due to an increase in opioid receptors in the spinal cord. Past studies did not consider the role of non-neuronal cells, which are now known to play an important role in chronic pain processing. Using an inflammatory (complete Freund's adjuvant) or neuropathic (spared nerve injury) model of persistent pain, we observed that young adult female mice in early pregnancy switch from a microglia-independent to a microglia-dependent pain hypersensitivity mechanism. During late pregnancy, female mice show no evidence of chronic pain whatsoever. This pregnancy-related analgesia is reversible by intrathecal administration of naloxone, suggesting an opioid-mediated mechanism; pharmacological and genetic data suggest the importance of δ-opioid receptors. We also observe that T-cell-deficient (nude and Rag1-null mutant) pregnant mice do not exhibit pregnancy analgesia, which can be rescued with the adoptive transfer of CD4+ or CD8+ T cells from late-pregnant wild-type mice. These results suggest that T cells are a mediator of the opioid analgesia exhibited during pregnancy.SIGNIFICANCE STATEMENT Chronic pain symptoms often subside during pregnancy. This pregnancy-related analgesia has been demonstrated for acute pain in rats. Here, we show that pregnancy analgesia can produce a complete cessation of chronic pain behaviors in mice. We show that the phenomenon is dependent on pregnancy hormones (estrogen and progesterone), δ-opioid receptors, and T cells of the adaptive immune system. These findings add to the recent but growing evidence of sex-specific T-cell involvement in chronic pain processing.

Effect of Body Position on Pharyngeal Swallowing Pressures Using High-Resolution Manometry.

The effect of body position and gravitational pull on the complex pressure-driven process of pharyngeal swallowing remains unknown. Using high-resolution manometry (HRM), this study aims to identify positional adaptations of pharyngeal physiology by evaluating swallowing pressure patterns in a series of inverted body positions. Ten healthy adults each underwent swallowing tasks with pharyngeal HRM at six body positions using an inversion table (0°[upright], 45°, 90°[supine], 110°, 135°, and 180°[fully inverted]). Repeated measures ANOVA was used to assess impact of position on pressure parameters, and pharyngeal-UES pressure gradients translate. Velopharyngeal pressures varied by position (P < 0.001), with significantly higher pressures generated with inversion ≥90°, compared with upright and 45°. Change in position did not significantly affect common mesopharyngeal pressures or swallowing pressure durations. UES valving mechanisms were preserved during inversion, with subtle variations observed in integral pressures (P = 0.011). Pharyngeal-UES pressure gradients changed with position (P < 0.01), increasing with inversion > 90° compared to upright and 45°. Mechanisms of deglutition may differ with position and relative direction of gravity, particularly when at > 45° inclination. Increased palatal pressure is generated in the upside-down position to achieve nasopharyngeal closure and prevent regurgitation. While other classically measured pressures may not consistently differ with positioning, many individuals exhibit adaptations in pressure gradients when inverted, likely due to a combination of changes in pharyngeal driving force and UES opening mechanisms. Identification of these changes, relative to position, further builds on our understanding of the adaptability of the pharyngeal swallowing system.

Sex differences in neuroimmunity and pain.

Differences in the prevalence of chronic pain in women vs. men are well known, and decades of laboratory experimentation have demonstrated that women are more sensitive to pain than are men. Attention has thus shifted to investigating mechanisms underlying such differences. Recent evidence suggests that neuroimmune modulation of pain may represent an important cause of sex differences. The current Review examines the evidence for gonadal hormone modulation of the immune system, immune system modulation of pain, and interactions that might help to explain sex differences in pain. © 2016 Wiley Periodicals, Inc.

Olfactory exposure to males, including men, causes stress and related analgesia in rodents.

We found that exposure of mice and rats to male but not female experimenters produces pain inhibition. Male-related stimuli induced a robust physiological stress response that results in stress-induced analgesia. This effect could be replicated with T-shirts worn by men, bedding material from gonadally intact and unfamiliar male mammals, and presentation of compounds secreted from the human axilla. Experimenter sex can thus affect apparent baseline responses in behavioral testing.

Crowding by a repeating pattern.

Theinability to recognize a peripheral target among flankers is called crowding. For a foveal target, crowding can be distinguished from overlap masking by its sparing of detection, linear scaling with eccentricity, and invariance with target size.Crowding depends on the proximity and similarity of the flankers to the target. Flankers that are far from or dissimilar to the target do not crowd it. On a gray page, text whose neighboring letters have different colors, alternately black and white, has enough dissimilarity that it might escape crowding. Since reading speed is normally limited by crowding, escape from crowding should allow faster reading. Yet reading speed is unchanged (Chung & Mansfield, 2009). Why? A recent vernier study found that using alternating-color flankers produces strong crowding (Manassi, Sayim, & Herzog, 2012). Might that effect occur with letters and reading? Critical spacing is the minimum center-to-center target-flanker spacing needed to correctly identify the target. We measure it for a target letter surrounded by several equidistant flanker letters of the same polarity, opposite polarity, or mixed polarity: alternately white and black. We find strong crowding in the alternating condition, even though each flanker letter is beyond its own critical spacing (as measured in a separate condition). Thus a periodic repeating pattern can produce crowding even when the individual elements do not. Further, in all conditions we find that, once a periodic pattern repeats (two cycles), further repetition does not affect critical spacing of the innermost flanker.

The umbilicus: a reliable surface landmark for the aortic bifurcation?

PURPOSE: Anatomical surface landmarks are frequently used by clinicians to guide both diagnosis and treatment. Few studies have examined the reliability of vascular anatomical landmarks in living subjects. The umbilicus has traditionally been described as a surface landmark for the bifurcation of the abdominal aorta. This study examined the factors affecting the position of the umbilicus relative to that of the aortic bifurcation in 95 patients. METHODS: 106 consecutive abdominal CT scans were analysed by a surgeon and radiologist. Following exclusion of CT scans with relevant significant intra-abdominal pathology, 95 patients were included in the study. Measurements were taken of the craniocaudal distance between the aortic bifurcation and umbilicus, as well as maximum subcutaneous fat thickness at the level of the umbilicus. Patient age and gender were also documented. RESULTS: The umbilicus was found to lie -6.3 ± 26.5 mm from the aortic bifurcation. Increasing subcutaneous fat thickness was associated with a more caudal position of the umbilicus relative to the aortic bifurcation. This result was highly statistically significant in males over 65 years old. CONCLUSIONS: This study suggests that the umbilicus is a reliable clinical surface landmark for the bifurcation of the abdominal aorta. Whilst some variation in craniocaudal distance exists between patients, in the majority of cases, the bifurcation of the abdominal aorta lies within a clinically narrow range of distances from the umbilicus.

The conserved P body component HPat/Pat1 negatively regulates synaptic terminal growth at the larval Drosophila neuromuscular junction.

The temporal and spatial regulation of protein synthesis plays an important role in the control of neural physiology. In axons and dendrites, translationally repressed mRNAs are actively transported to their destinations in a variety of ribonucleoprotein particles (RNPs). A subset of these neuronal RNPs has been shown to contain proteins associated with mRNA processing bodies (P bodies). P bodies are a class of highly conserved cytoplasmic granules that have been linked to both mRNA decay and translational repression via general and miRNA-mediated pathways. Here, we characterize functions for HPat/Pat1 (also known as Patr-1), a core component of P bodies, at the glutamatergic larval Drosophila neuromuscular junction (NMJ). We show that hpat mutants exhibit a strong synaptic hyperplasia at the NMJ. The synaptic defects observed in hpat mutants are associated with rearrangement of the axonal microtubule cytoskeleton suggesting that HPat negatively regulates presynaptic microtubule-based growth during NMJ development. Consistent with this, overexpression of HPat also blocks the rapid growth of presynaptic boutons induced by spaced depolarization. Finally, we demonstrate that HPat interacts genetically with the catalytic subunit of the deadenylase complex (twin/CCR4) and the miRNA pathway (Argonaute 1) to control bouton formation. We propose that HPat is required to target mRNAs involved in the control of microtubule architecture and synaptic terminal growth for repression, presumably in P bodies, via both general and miRNA-mediated mechanisms.

The Bouma law of crowding, revised: critical spacing is equal across parts, not objects.

Crowding is the inability to identify an object among flankers in the periphery. It is due to inappropriate incorporation of features from flanking objects in perception of the target. Crowding is characterized by measuring critical spacing, the minimum distance needed between a target and flankers to allow recognition. The existing Bouma law states that, at a given point and direction in the visual field, critical spacing, measured from the center of a target object to the center of a similar flanking object, is the same for all objects (Pelli & Tillman, 2008). Because flipping an object about its center preserves its center-to-center spacing to other objects, according to the Bouma law, crowding should be unaffected. However, because crowding is a result of feature combination, the location of features within an object might matter. In a series of experiments, we find that critical spacing is affected by the location of features within the flanker. For some flankers, a flip greatly reduces crowding even though it maintains target-flanker spacing and similarity. Our results suggest that the existing Bouma law applies to simple one-part objects, such as a single roman letter or a Gabor patch. Many objects consist of multiple parts; for example, a word is composed of multiple letters that crowd each other. To cope with such complex objects, we revise the Bouma law to say that critical spacing is equal across parts, rather than objects. This accounts for old and new findings.

Impact of Obesity on Timing of Tracheotomy: A Multi-institutional Retrospective Study.

OBJECTIVE: To examine the impact of increased body mass index (BMI) on (1) tracheotomy timing and (2) short-term surgical complications requiring a return to the operating room and 30-day mortality utilizing data from the Multi-Institutional Study on Tracheotomy (MIST). METHODS: A retrospective analysis of patients from the MIST database who underwent surgical or percutaneous tracheotomy between 2013 and 2016 at eight institutions was completed. Unadjusted and adjusted logistic regression analyses were used to assess the impact of obesity on tracheotomy timing and complications. RESULTS: Among the 3369 patients who underwent tracheotomy, 41.0% were obese and 21.6% were morbidly obese. BMI was associated with higher rates of prolonged intubation prior to tracheotomy accounting for comorbidities, indication for tracheotomy, institution, and type of tracheostomy (p = 0.001). Morbidly obese patients (BMI ≥35 kg/m2) experienced a longer duration of intubation compared with patients with a normal BMI (median days intubated [IQR 25%-75%]: 11.0 days [7-17 days] versus 9.0 days [5-14 days]; p < 0.001) but did not have statistically higher rates of return to the operating room within 30 days (p = 0.12) or mortality (p = 0.90) on multivariable analysis. This same finding of prolonged intubation was not seen in overweight, nonobese patients when compared with normal BMI patients (median days intubated [IQR 25%-75%]: 10.0 days [6-15 days] versus 10.0 days [6-15 days]; p = 0.36). CONCLUSION: BMI was associated with increased duration of intubation prior to tracheotomy. Although morbidly obese patients had a longer duration of intubation, there were no differences in return to the operating room or mortality within 30 days. LEVEL OF EVIDENCE: III Laryngoscope, 2024.

Factors Associated With Otolaryngologists Performing Tracheotomy.

Importance: Tracheotomies are frequently performed by nonotolaryngology services. The factors that determine which specialty performs the procedure are not defined in the literature but may be influenced by tracheotomy approach (open vs percutaneous) and other clinicodemographic factors. Objective: To evaluate demographic and clinical characteristics associated with tracheotomies performed by otolaryngologists compared with other specialists and to differentiate those factors from factors associated with use of open vs percutaneous tracheotomy. Design, Setting, and Participants: This multicenter, retrospective cohort study included patients aged 18 years or older who underwent a tracheotomy for cardiopulmonary failure at 1 of 8 US academic institutions between January 1, 2013, and December 31, 2016. Data were analyzed from September 2022 to July 2023. Exposure: Tracheotomy. Main Outcomes and Measures: The primary outcome was factors associated with an otolaryngologist performing tracheotomy. The secondary outcome was factors associated with use of the open tracheotomy technique. Results: A total of 2929 patients (mean [SD] age, 57.2 [17.2] years; 1751 [59.8%] male) who received a tracheotomy for cardiopulmonary failure (652 [22.3%] performed by otolaryngologists and 2277 [77.7%] by another service) were analyzed. Although 1664 of all tracheotomies (56.8%) were performed by an open approach, only 602 open tracheotomies (36.2%) were performed by otolaryngologists. Most tracheotomies performed by otolaryngologists (602 of 652 [92.3%]) used the open technique. Multivariable regression analysis revealed that self-reported Black race (odds ratio [OR], 1.89; 95% CI, 1.52-2.35), history of neck surgery (OR, 2.71; 95% CI, 2.06-3.57), antiplatelet and/or anticoagulation therapy (OR, 1.74; 95% CI, 1.29-2.36), and morbid obesity (OR, 1.54; 95% CI, 1.24-1.92) were associated with greater odds of an otolaryngologist performing tracheotomy. In contrast, history of neck surgery (OR, 1.36; 95% CI, 0.96-1.92), antiplatelet and/or anticoagulation therapy (OR, 0.80; 95% CI, 0.56-1.14), and morbid obesity (OR, 0.94; 95% CI, 0.74-1.19) were not associated with undergoing open tracheotomy when performed by any service, and Black race (OR, 0.56; 95% CI, 0.44-0.71) was associated with lesser odds of an open approach being used. Age-adjusted Charlson Comorbidity Index score greater than 4 was associated with greater odds of both an otolaryngologist performing tracheotomy (OR, 1.26; 95% CI, 1.03-1.53) and use of the open tracheotomy technique (OR, 1.48, 95% CI, 1.21-1.82). Conclusions and Relevance: In this study, otolaryngologists were significantly more likely than other specialists to perform a tracheotomy for patients with history of neck surgery, morbid obesity, and ongoing anticoagulation therapy. These findings suggest that patients undergoing tracheotomy performed by an otolaryngologist are more likely to present with complex and challenging clinical characteristics.

Understanding the relative affinity and specificity of the pleckstrin homology domain of protein kinase B for inositol phosphates.

Protein kinase B (PKB) is a serine/threonine kinase that plays a key role in the phosphoinositide 3-kinase (PI3K) pathway-one of the most frequently activated proliferation pathways in cancer. In this pathway, PKB is recruited to the plasma membrane by direct interaction of its pleckstrin homology (PH) domain with the inositol phosphate head-group of phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)] or phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P(2)]. This recruitment is a critical stage in the activation of PKB, whose downstream effectors play important roles in cell survival, proliferation and growth. It is therefore of great interest to understand PKB's mode of binding, as well as its specificity and affinity for different phosphoinositides. We have used a total of 3 µs of molecular dynamics (MD) simulations to better understand the interactions of the PKB PH domain with the inositol phosphate head-groups of phosphoinositides involved in the PI3K pathway. Our computational models successfully mirror PKB's in vivo selectivity for 3-phosphorylated phosphoinositides. Furthermore, the models also help to rationalize unexpected in vitro data in which inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] binds with a relatively high affinity to the PKB PH domain, despite its parent lipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] being known not to bind in vivo. With the support of computational simulations, we propose that when not bonded to a phosphatidate tail Ins(1,4,5)P(3) binds in an orientation in which its inositol ring is flipped with respect to the 3-phosphorylated inositol phosphate ligands and its parent lipid.

Using a checklist within simulation improves trainees' confidence on ward rounds.

Ward rounds are integral to maintaining patient safety in everyday clinical care. Junior doctors are often expected to conduct independent rounds on graduation, but many feel ill-equipped to do so. We developed a safety checklist and simulation sessions to improve junior-led ward round practice at one district general hospital. We found that embedding a checklist within simulation is an effective way to teach ward round skills and increase confidence among undergraduate and postgraduate medical trainees.

Single-cell RNA transcriptome analysis of CNS immune cells reveals CXCL16/CXCR6 as maintenance factors for tissue-resident T cells that drive synapse elimination.

BACKGROUND: Emerging RNA viruses that target the central nervous system (CNS) lead to cognitive sequelae in survivors. Studies in humans and mice infected with West Nile virus (WNV), a re-emerging RNA virus associated with learning and memory deficits, revealed microglial-mediated synapse elimination within the hippocampus. Moreover, CNS-resident memory T (TRM) cells activate microglia, limiting synapse recovery and inducing spatial learning defects in WNV-recovered mice. The signals involved in T cell-microglia interactions are unknown. METHODS: Here, we examined immune cells within the murine WNV-recovered forebrain using single-cell RNA sequencing to identify putative ligand-receptor pairs involved in intercellular communication between T cells and microglia. Clustering and differential gene analyses were followed by protein validation and genetic and antibody-based approaches utilizing an established murine model of WNV recovery in which microglia and complement promote ongoing hippocampal synaptic loss. RESULTS: Profiling of host transcriptome immune cells at 25 days post-infection in mice revealed a shift in forebrain homeostatic microglia to activated subpopulations with transcriptional signatures that have previously been observed in studies of neurodegenerative diseases. Importantly, CXCL16/CXCR6, a chemokine signaling pathway involved in TRM cell biology, was identified as critically regulating CXCR6 expressing CD8+ TRM cell numbers within the WNV-recovered forebrain. We demonstrate that CXCL16 is highly expressed by all myeloid cells, and its unique receptor, CXCR6, is highly expressed on all CD8+ T cells. Using genetic and pharmacological approaches, we demonstrate that CXCL16/CXCR6 not only is required for the maintenance of WNV-specific CD8 TRM cells in the post-infectious CNS, but also contributes to their expression of TRM cell markers. Moreover, CXCR6+CD8+ T cells are required for glial activation and ongoing synapse elimination. CONCLUSIONS: We provide a comprehensive assessment of the role of CXCL16/CXCR6 as an interaction link between microglia and CD8+ T cells that maintains forebrain TRM cells, microglial and astrocyte activation, and ongoing synapse elimination in virally recovered animals. We also show that therapeutic targeting of CXCL16 in mice during recovery may reduce CNS CD8+ TRM cells.

Olfactory exposure to late-pregnant and lactating mice causes stress-induced analgesia in male mice.

In an attempt to improve reproducibility, more attention is being paid to potential sources of stress in the laboratory environment. Here, we report that the mere proximity of pregnant or lactating female mice causes olfactory-mediated stress-induced analgesia, to a variety of noxious stimuli, in gonadally intact male mice. We show that exposure to volatile compounds released in the urine of pregnant and lactating female mice can themselves produce stress and associated pain inhibition. This phenomenon, a novel form of female-to-male chemosignaling, is mediated by female scent marking of urinary volatiles, such as n-pentyl-acetate, and likely signals potential maternal aggression aimed at defending against infanticide by stranger males.

Long-term male-specific chronic pain via telomere- and p53­mediated spinal cord cellular senescence.

Mice with experimental nerve damage can display long­lasting neuropathic pain behavior. We show here that 4 months and later after nerve injury, male but not female mice displayed telomere length (TL) reduction and p53­mediated cellular senescence in the spinal cord, resulting in maintenance of pain and associated with decreased lifespan. Nerve injury increased the number of p53­positive spinal cord neurons, astrocytes, and microglia, but only in microglia was the increase male­specific, matching a robust sex specificity of TL reduction in this cell type, which has been previously implicated in male­specific pain processing. Pain hypersensitivity was reversed by repeated intrathecal administration of a p53­specific senolytic peptide, only in male mice and only many months after injury. Analysis of UK Biobank data revealed sex-specific relevance of this pathway in humans, featuring male­specific genetic association of the human p53 locus (TP53) with chronic pain and a male-specific effect of chronic pain on mortality. Our findings demonstrate the existence of a biological mechanism maintaining pain behavior, at least in males, occurring much later than the time span of virtually all extant preclinical studies.

A theoretical investigation of inositol 1,3,4,5-tetrakisphosphate.

This paper describes the parameterization of inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P(4)] for use in molecular dynamics (MD) simulations. For this theoretical investigation, eleven isomers of Ins(1,3,4,5)P(4), with different levels and arrangements of protonation, have been considered. Herein we report accurate quantum mechanics (QM) calculations offering a detailed description of the energetic and structural properties of the Ins(1,3,4,5)P(4) isomers and subsequent development of parameters for these isomers for application in the AMBER force field. QM calculations were employed to geometry optimize the Ins(1,3,4,5)P(4) isomers, using the DFT-B3LYP level of theory in gas phase. In subsequent steps, charge parameters were generated for each isomer. These charge parameters, plus assigned atom-types from the AMBER ff99SB force field, were then applied to the optimized isomers for energy minimization in AMBER. The quality of the parameters was evaluated by comparing the structural, energetic and spectroscopic properties of the Ins(1,3,4,5)P(4) isomers between the QM geometry optimization stage, from which the parameters were generated, and the energy minimization stage, in which the parameters were applied. The results were shown to be in strong qualitative agreement between these stages, suggesting good quality parameters have been obtained. Additionally, adaptations to the gas phase protocol, investigating the use of the MP2 method for the geometry optimization stage and GAFF atom-types for the energy minimization stage, were tested. These results confirmed the initial protocol applied was the most appropriate. Calculations for the Ins(1,3,4,5)P(4) isomers were also carried out in the presence of implicit solvent, allowing comparison and validation of the theoretical calculations with experimental data. The computed energetic properties of the Ins(1,3,4,5)P(4) isomers were assessed against their experimental probabilities based on (31)P-NMR titration data. The computational and experimental results were shown to be in strong agreement, with the lower energy isomers corresponding to those more probable. This paper reports a clearly-defined algorithmic approach to generate parameters for the highly charged Ins(1,3,4,5)P(4) ligand, permitting their use in future MD studies.

Spectral arc length as a method to quantify pharyngeal high-resolution manometric curve smoothness.

BACKGROUND: Pharyngeal high-resolution manometry (HRM) has emerged over the last decade as a valuable assessment tool for oropharyngeal dysphagia. Data analysis thus far has focused primarily on measures of pressure and duration within key anatomic regions. We apply spectral arc length (SPARC), a dimensionless metric for quantifying smoothness felt to indirectly reflect neuromuscular coordination, as a new method of describing manometric curves. We then use it to distinguish swallows from healthy subjects and those with dysphagia related to stroke. METHODS: Previously collected pharyngeal HRM data from eight subjects with history of stroke and eight age- and sex-matched controls were reviewed. Receiver operating characteristic (ROC) analysis was used to optimize SPARC inputs. SPARC was then computed for the velopharynx, tongue base, hypopharynx, and upper esophageal sphincter (UES), and the values were compared between the two subject groups. RESULTS: Optimized parameter settings yielded an ROC curve with area under the curve (AUC) of 0.953. Mean SPARC values differed between control and stroke subjects for the velopharynx (t = 3.25, p = 0.0058), tongue base (t = 4.77, p = 0.0003), and hypopharynx (t = 2.87, p = 0.0124). Values were similar for the UES (t = 0.43, p = 0.671). CONCLUSIONS: In this preliminary study, SPARC analysis was applied to distinguish control from post-stroke subjects. Considering alternative methods of analyzing pharyngeal HRM data may provide additional insight into the pathophysiology of dysphagia beyond what can be gleaned from measures of pressure and duration alone.

Decreased antiviral immune response within the central nervous system of aged mice is associated with increased lethality of West Nile virus encephalitis.

West Nile virus (WNV) is an emerging pathogen that causes disease syndromes ranging from a mild flu-like illness to encephalitis. While the incidence of WNV infection is fairly uniform across age groups, the risk of lethal encephalitis increases with advanced age. Prior studies have demonstrated age-related, functional immune deficits that limit systemic antiviral immunity and increase mortality; however, the effect of age on antiviral immune responses specifically within the central nervous system (CNS) is unknown. Here, we show that aged mice exhibit increased peripheral organ and CNS tissue viral burden, the latter of which is associated with alterations in activation of both myeloid and lymphoid cells compared with similarly infected younger animals. Aged mice exhibit lower MHCII expression by microglia, and higher levels of PD1 and lower levels of IFNγ expression by WNV-specific CD8+ T cells in the CNS and CD8+ CD45+ cells. These data indicate that the aged CNS exhibits limited local reactivation of T cells during viral encephalitis, which may lead to reduced virologic control at this site.