615 research outputs found
Modeling-based determination of physiological parameters of systemic VOCs by breath gas analysis, part 2
In a recent paper we presented a simple two compartment model which describes
the influence of inhaled concentrations on exhaled breath concentrations for
volatile organic compounds (VOCs) with small Henry constants. In this paper we
extend this investigation concerning the influence of inhaled concentrations on
exhaled breath concentrations for VOCs with higher Henry constants.
To this end we extend our model with an additional compartment which takes
into account the influence of the upper airways on exhaled breath VOC
concentrations
Some Biochemical Properties of Pemphigoid Antigen Bound to the Surface of Dissociated Epidermal Basal Cells
Bullous pemphigoid antigen (BP Ag) is a cell surface marker of epidermal basal cells. The functional role of this molecule is unknown. Epidermal cell suspensions obtained by trypsinization of skin show a population of epidermal basal cells with a polar rim of antigen as demonstrated by indirect immunofluorescence technique. This study shows that treatment of these cells suspensions with a variety of proteolytic and glycosidic enzymes failed to remove the antigen from these basal cells. BP Ag was also stable upon incubation with distilled water, Triton X-100, PBS, and 1 m NaCl. Treatment of epidermal basal cells with 2 n NaSCN, 1% periodic acid, and 4 m urea, as well as acidic pH or 56°C temperature, abolished the reactivity of these cells with BP antibodies
Nanoscale -Nuclear Magnetic Resonance Depth Imaging of Topological Insulators
Considerable evidence suggests that variations in the properties of
topological insulators (TIs) at the nanoscale and at interfaces can strongly
affect the physics of topological materials. Therefore, a detailed
understanding of surface states and interface coupling is crucial to the search
for and applications of new topological phases of matter. Currently, no methods
can provide depth profiling near surfaces or at interfaces of topologically
inequivalent materials. Such a method could advance the study of interactions.
Herein we present a non-invasive depth-profiling technique based on -NMR
spectroscopy of radioactive Li ions that can provide "one-dimensional
imaging" in films of fixed thickness and generates nanoscale views of the
electronic wavefunctions and magnetic order at topological surfaces and
interfaces. By mapping the Li nuclear resonance near the surface and 10 nm
deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we
provide signatures related to the TI properties and their topological
non-trivial characteristics that affect the electron-nuclear hyperfine field,
the metallic shift and magnetic order. These nanoscale variations in
-NMR parameters reflect the unconventional properties of the topological
materials under study, and understanding the role of heterogeneities is
expected to lead to the discovery of novel phenomena involving quantum
materials.Comment: 46 pages, 12 figures in Proc. Natl. Aca. Sci. USA (2015) Published
online - early editio
Analysis of Oocyte-Like Cells Differentiated from Porcine Fetal Skin-Derived Stem Cells
We previously reported the differentiation of cells derived from porcine female fetal skin into cells resembling germ cells and oocytes. A subpopulation of these cells expressed germ cell markers and formed aggregates resembling cumulus-oocyte complexes. Some of these aggregates extruded large oocyte-like cells (OLCs) that expressed markers consistent with those of oocytes. The objective of the current study was to further characterize OLCs differentiated from porcine skin-derived stem cells. Reverse transcriptase (RT)-polymerase chain reaction and Western blot revealed the expression of connexin37 and connexin43, both of which are characteristic of ovarian follicles. The expression of meiosis markers DMC1 and synaptonemal complex protein, but not STRA8 and REC8, was detected in the OLC cultures. Immunofluorescence with an antibody against synaptonemal complex protein on chromosome spreads revealed a very small subpopulation of stained OLCs that had a similar pattern to leptotene, zytotene, or pachytene nuclei during prophase I of meiosis. Sodium bisulfite sequencing of the differentially methylated region of H19 indicated that this region is almost completely demethylated in OLCs, similar to in vivo-derived oocytes. We also investigated the differentiation potential of male skin-derived stem cells in the same differentiation medium. Large cells with oocyte morphology were generated in the male stem cell differentiation cultures. These OLCs expressed oocyte genes such as octamer-binding transcription factor 4 (OCT4), growth differentiation factor-9b (GDF9B), deleted in azoospermia-like (DAZL), VASA, zona pellucida B (ZPB), and zona pellucida C (ZPC). It was concluded that skin-derived stem cells from both male and female porcine fetuses are capable of entering an oocyte differentiation pathway, but the culture system currently in place is inadequate to support the complete development of competent oocytes
A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone
Recommended standardized procedures for determining exhaled lower respiratory
nitric oxide and nasal nitric oxide have been developed by task forces of the
European Respiratory Society and the American Thoracic Society. These
recommendations have paved the way for the measurement of nitric oxide to
become a diagnostic tool for specific clinical applications. It would be
desirable to develop similar guidelines for the sampling of other trace gases
in exhaled breath, especially volatile organic compounds (VOCs) which reflect
ongoing metabolism. The concentrations of water-soluble, blood-borne substances
in exhaled breath are influenced by: (i) breathing patterns affecting gas
exchange in the conducting airways; (ii) the concentrations in the
tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations
of the compound. The classical Farhi equation takes only the alveolar
concentrations into account. Real-time measurements of acetone in end-tidal
breath under an ergometer challenge show characteristics which cannot be
explained within the Farhi setting. Here we develop a compartment model that
reliably captures these profiles and is capable of relating breath to the
systemic concentrations of acetone. By comparison with experimental data it is
inferred that the major part of variability in breath acetone concentrations
(e.g., in response to moderate exercise or altered breathing patterns) can be
attributed to airway gas exchange, with minimal changes of the underlying blood
and tissue concentrations. Moreover, it is deduced that measured end-tidal
breath concentrations of acetone determined during resting conditions and free
breathing will be rather poor indicators for endogenous levels. Particularly,
the current formulation includes the classical Farhi and the Scheid series
inhomogeneity model as special limiting cases.Comment: 38 page
Long-Term Complications of Ebola Virus Disease: Prevalence and Predictors of Major Symptoms and the Role of Inflammation
Background
Cohort studies have reported a high prevalence of musculoskeletal, neurologic, auditory, and visual complications among Ebola virus disease (EVD) survivors. However, little is known about the host- and disease-related predictors of these symptoms and their etiological mechanisms.
Methods
The presence and patterns of 8 cardinal symptoms that are most commonly reported following EVD survival were assessed in the 326 EVD survivors who participated in the ongoing longitudinal Liberian EVD Survivor Study. At quarterly study visits, symptoms that developed since acute EVD were recorded and blood was collected for biomarkers of inflammation and immune activation.
Results
At baseline (mean 408 days from acute EVD), 75.5% of survivors reported at least 1 new cardinal symptom since surviving EVD, which in 85.8% was rated as highly interfering with life. Two or more incident symptoms were reported by 61.0% of survivors, with pairings of joint pain, headache, or fatigue the most frequent. Women were significantly more likely than men to report headache, while older age was significantly associated with musculoskeletal and visual symptoms. In analyses adjusted for multiple comparisons, no statistically significant association was found between any symptom and 26 markers of inflammation and immune activation. Symptom frequency remained largely unchanged during study follow-up.
Conclusions
Post-EVD complications occur in a majority of survivors and remain present more than 4 years after acute infection. An association between markers of inflammation and immune activation and individual symptoms was not found, suggesting an alternative etiology for persistent post-EVD symptomatology
9th Biennial Judge Joe Lee Bankruptcy Institute
Materials from the 9th Biennial Judge Joe Lee Bankruptcy Institute held December 1999
Is Persistent Motor or Vocal Tic Disorder a Milder Form of Tourette Syndrome?
BACKGROUND: Persistent motor or vocal tic disorder (PMVT) has been hypothesized to be a forme fruste of Tourette syndrome (TS). Although the primary diagnostic criterion for PMVT (presence of motor or vocal tics, but not both) is clear, less is known about its clinical presentation. OBJECTIVE: The goals of this study were to compare the prevalence and number of comorbid psychiatric disorders, tic severity, age at tic onset, and family history for TS and PMVT. METHODS: We analyzed data from two independent cohorts using generalized linear equations and confirmed our findings using meta‐analyses, incorporating data from previously published literature. RESULTS: Rates of obsessive–compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) were lower in PMVT than in TS in all analyses. Other psychiatric comorbidities occurred with similar frequencies in PMVT and TS in both cohorts, although meta‐analyses suggested lower rates of most psychiatric disorders in PMVT compared with TS. ADHD and OCD increased the odds of comorbid mood, anxiety, substance use, and disruptive behaviors, and accounted for observed differences between PMVT and TS. Age of tic onset was approximately 2 years later, and tic severity was lower in PMVT than in TS. First‐degree relatives had elevated rates of TS, PMVT, OCD, and ADHD compared with population prevalences, with rates of TS equal to or greater than PMVT rates. CONCLUSIONS: Our findings support the hypothesis that PMVT and TS occur along a clinical spectrum in which TS is a more severe and PMVT a less severe manifestation of a continuous neurodevelopmental tic spectrum disorder. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Societ
Clinically Actionable Hypercholesterolemia and Hypertriglyceridemia in Children with Nonalcoholic Fatty Liver Disease
OBJECTIVE:
To determine the percentage of children with nonalcoholic fatty liver disease (NAFLD) in whom intervention for low-density lipoprotein cholesterol or triglycerides was indicated based on National Heart, Lung, and Blood Institute guidelines.
STUDY DESIGN:
This multicenter, longitudinal cohort study included children with NAFLD enrolled in the National Institute of Diabetes and Digestive and Kidney Diseases Nonalcoholic Steatohepatitis Clinical Research Network. Fasting lipid profiles were obtained at diagnosis. Standardized dietary recommendations were provided. After 1 year, lipid profiles were repeated and interpreted according to National Heart, Lung, and Blood Institute Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction. Main outcomes were meeting criteria for clinically actionable dyslipidemia at baseline, and either achieving lipid goal at follow-up or meeting criteria for ongoing intervention.
RESULTS:
There were 585 participants, with a mean age of 12.8 years. The prevalence of children warranting intervention for low-density lipoprotein cholesterol at baseline was 14%. After 1 year of recommended dietary changes, 51% achieved goal low-density lipoprotein cholesterol, 27% qualified for enhanced dietary and lifestyle modifications, and 22% met criteria for pharmacologic intervention. Elevated triglycerides were more prevalent, with 51% meeting criteria for intervention. At 1 year, 25% achieved goal triglycerides with diet and lifestyle changes, 38% met criteria for advanced dietary modifications, and 37% qualified for antihyperlipidemic medications.
CONCLUSIONS:
More than one-half of children with NAFLD met intervention thresholds for dyslipidemia. Based on the burden of clinically relevant dyslipidemia, lipid screening in children with NAFLD is warranted. Clinicians caring for children with NAFLD should be familiar with lipid management
The Prevalence and Influence of New or Worsened Neck Pain After a Sport-Related Concussion in Collegiate Athletes: A Study From the CARE Consortium
BACKGROUND: Neck pain in a concussion population is an emerging area of study that has been shown to have a negative influence on recovery. This effect has not yet been studied in collegiate athletes.
HYPOTHESIS: New or worsened neck pain is common after a concussion (>30%), negatively influences recovery, and is associated with patient sex and level of contact in sport.
STUDY DESIGN: Cohort study; Level of evidence, 2.
METHODS: Varsity-level athletes from 29 National Collegiate Athletic Association member institutions as well as nonvarsity sport athletes at military service academies were eligible for enrollment. Participants completed a preseason baseline assessment and follow-up assessments at 6 and 24 to 48 hours after a concussion, when they were symptom-free, and when they returned to unrestricted play. Data collection occurred between January 2014 and September 2018.
RESULTS: A total of 2163 injuries were studied. New or worsened neck pain was reported with 47.0% of injuries. New or worsened neck pain was associated with patient sex (higher in female athletes), an altered mental status after the injury, the mechanism of injury, and what the athlete collided with. The presence of new/worsened neck pain was associated with delayed recovery. Those with new or worsened neck pain had 11.1 days of symptoms versus 8.8 days in those without (P < .001). They were also less likely to have a resolution of self-reported symptoms in ≤7 days (P < .001). However, the mean duration of the return-to-play protocol was not significantly different for those with new or worsened neck pain (7.5 ± 7.7 days) than those without (7.4 ± 8.3 days) (P = .592).
CONCLUSION: This novel study shows that neck pain was common in collegiate athletes sustaining a concussion, was influenced by many factors, and negatively affected recovery
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