Background. The gut is a major reservoir for human immunodeficiency virus (HIV) in patients receiving antiretroviral therapy (ART). We hypothesized that distinct immune environments within the gut ...may support varying levels of HIV. Methods. In 8 HIV-1-positive adults who were receiving ART and had CD4+ T cell counts of >200 cells/µL and plasma viral loads of <40 copies/mL, levels of HIV and T cell activation were measured in blood samples and endoscopic biopsy specimens from the duodenum, ileum, ascending colon, and rectum. Results. HIV DNA and RNA levels per CD4+ T cell were higher in all 4 gut sites compared with those in the blood. HIV DNA levels increased from the duodenum to the rectum, whereas the median HIV RNA level peaked in the ileum. HIV DNA levels correlated positively with T cell activation markers in peripheral blood mononuclear cells (PBMCs) but negatively with T cell activation markers in the gut. Multiply spliced RNA was infrequently detected in gut, and ratios of unspliced RNA to DNA were lower in the colon and rectum than in PBMCs, which reflects paradoxically low HIV transcription, given the higher level of T cell activation in the gut. Conclusions. HIV DNA and RNA are both concentrated in the gut, but the inverse relationship between HIV DNA levels and T cell activation in the gut and the paradoxically low levels of HIV expression in the large bowel suggest that different processes drive HIV persistence in the blood and gut. Trial registration. ClinicalTrials.gov identifier: NCT00884793 (PLUS1).
Improved limit on the muon electric dipole moment Bennett, G. W.; Bousquet, B.; Brown, H. N. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2009, Letnik:
80, Številka:
5
Journal Article
Both methylmercury (MeHg) and inorganic divalent mercury (Hg++) alter the flux of ions and small molecules across nerve terminal membranes by mechanisms that may involve membrane depolarization. We ...compared the effects of MeHg and Hg++ on plasma (psi p) and mitochondrial membrane potentials (psi m) in synaptosomes using the potentiometric carbocyanine dye 3,3'-diethylthiadicarbocyanine iodide diS-C2(5). Both mercurials (1-20 microM) produced concentration-dependent increases in dye fluorescence after 5 min of exposure which were not altered by removal of Ca++ from the medium. To determine directly effects of mercurials on psi p, predepolarization of psi m using NaN3 and oligomycin was necessary. Under this condition, MeHg- and Hg(++)-induced increases in fluorescence were associated with depolarization of psi p. A second approach was used to assess changes in psi p. In synaptosomes, the magnitude of the increase in fluorescence resulting from depolarization of psi p with a stimulus of constant intensity is a function of the resting psi p. The fluorescence response to depolarization of synaptosomes previously exposed to either MeHg or Hg++ (1-20 microM each) was reduced in a concentration-dependent manner relative to mercury-free controls. The concentration-dependent depolarization of psi p calculated in this manner correlated (r = 0.958) with calculations of psi p using direct measurements of increases in fluorescence intensity. MeHg- and Hg(++)-induced depolarizations were not altered by lowering Na+e or by the addition of the Na+ and Ca++ channel blockers tetrodotoxin and Co++, respectively. Thus, the effects of these two neurotoxic mercurials on synaptosomal membrane potentials were similar with respect to their loci but differed in magnitude.
Telehealth (TH) visits have been growing with exponential increased utilization during the COVID-19 pandemic. The aim of this manuscript is to describe the implementation and early experience of a ...pediatric electrophysiology (EP) TH program implemented during the pandemic, assessing patient satisfaction, patient equity and inclusion (measured by geographical outreach), and sustainability.
A retrospective chart review study was performed and data were collected from the medical record, including demographic, testing, and billing data from scheduled TH encounters between March and August 2020 of a single pediatric EP group in the Midwest. Patients were called to complete satisfaction surveys.
Patients with diverse pathologies were seen in TH, with supraventricular/atrial tachycardias (n = 41, 35%) and inherited arrhythmia syndromes (n = 23, 20%) being most common. The mean distance from clinic was 95 miles (range 2.8–320 miles), with 43% of patients living more than 100 miles away from clinic. A total of 172 tests were performed previsit (n = 102, 59%), during the visit (n = 17, 10%), or postvisit (n = 53, 31%), including 15 EP studies. Time-based Current Procedural Terminology codes were predominantly used for billing purposes (n = 92, 78%). There was generation of work relative value units (wRVU) for visits (220.5 wRVU) and testing (325.1 wRVU). Survey data demonstrated that 98% of patients were satisfied with their telehealth appointment and 99% had a clear understanding of their diagnosis.
Pediatric EP TH clinics can provide care for a geographically and pathologically heterogeneous group of patients who had positive attitudes toward TH. Our study shows significant downstream testing and subsequent wRVU generation, suggesting financial sustainability.
The effects of the neurotoxic organomercurial methylmercury (MeHg) on intrasynaptosomal polyvalent cation concentrations were examined using fura-2. In the presence of extracellular Ca2+ (Ca2+e), ...MeHg caused a concentration-dependent, biphasic elevation in the ratio of fluorescence intensity at the emission wavelength of 505 nm following excitation at 340 and 380 nm (340/380 nm ratio). The first phase was independent of Ca2+e and complete within 5 sec. The second phase was dependent upon Ca2+e and was not complete within 6 min. MeHg increased the synaptosomal membrane permeability to Mn2+, suggesting that the second phase was due to influx of Ca2+e. Ruthenium red (20 microM), mitochondrial depolarization (10 mM NaN3 plus 4 micrograms/ml oligomycin), thapsigargin (1 microM), or caffeine (40 mM) did not elevate Ca2+i or alter the response of the synaptosomes to MeHg. Upon closer inspection, we noticed that MeHg simultaneously increased the fluorescence intensity at the excitation wavelengths of 340 and 380 nm and at the Ca(2+)-insensitive excitation wavelength of 360 nm. Pretreatment of synaptosomes with the cell-permeant heavy metal chelator TPEN (50 microM) blocked the MeHg-induced elevations in the 360-nm intensity and the 340/380 nm ratio. TPEN given after MeHg reversed the elevations in the 360-nm intensity. The cell-impermeant heavy metal chelator DTPA (150 microM) had no effect. We conclude that MeHg disrupts polyvalent cation homeostasis by at least two mechanisms. The first involves release of endogenous non-Ca2+ polyvalent cations, while the second is due to increased Ca2+ permeability of the plasma membrane.
The three‐dimensional solution‐state structure is reported for the zinc‐substituted form of rubredoxin (Rd) from the marine hyperthermophilic archaebacterium Pyrococcus furiosus, an organism that ...grows optimally at 100°C. Structures were generated with DSPACE by a hybrid distance geometry (DG)‐based simulated annealing (SA) approach that employed 403 nuclear Overhauser effect (NOE)‐derived interproton distance restraints, including 67 interresidue, 124 sequential (i – j = 1), 75 medium‐range (i – j = 2–5), and 137 long‐range (i – j > 5) restraints. All lower interproton distance bounds were set at the sum of the van Der Waals radii (1.8 å), and upper bounds of 2.7 å, 3.3 å, and 5.0 å were employed to represent qualitatively observed strong, medium, and weak NOE cross peak intensities, respectively. Twenty‐three backbone‐backbone, six backbone‐sulfur (Cys), two backbone‐side chain, and two side chain‐side chain hydrogen bond restraints were include for structure refinement, yielding a total of 436 nonbonded restraints, which averages to > 16 restraints per residue. A total of 10 structures generated from random atom positions and 30 structures generated by molecular replacement using the backbone coordinates of Clostridium pasteurianum Rd converged to a common conformation, with the average penalty (= sum of the square of the distance bounds violations; ± standard deviation) of 0.024 ± 0.003 å2 and a maximum total penalty of 0.035 å2. Superposition of the backbone atoms (C, Cα, N) of residues A1‐L51 for all 40 structures afforded an average pairwise root mean square (rms) deviation value (±SD) of 0.42 ± 0.07 å. Superposition of all heavy atoms for residues A1‐L51, including those of structurally undefined external side chains, afforded an average pairwise rms deviation of 0.72 ± 0.08 å. Qualitative comparison of back‐calculated and experimental two‐dimensional NOESY spectra indicate that the DG/SA structures are consistent with the experimental spectra. The global folding of P. furiosus Zn(Rd) is remarkably similar to the folding observed by X‐ray crystallography for native Rd from the mesophilic organism C. pasteurianum, with the average rms deviation value for backbone atoms of residues A1‐L51 of P. furiosus Zn(Rd) superposed with respect to residues K2–V52 of C. pasteurianum Rd of 0.77 ± 0.06 å. The conformations of aromatic residues that compose the hydrophobic cores of the two proteins are also similar. However, P. furiosus Rd contains several unique structural elements, including at least four additional hydrogen bonds and three potential electrostatic interactions. Four of these interactions involve the nonconservatively substituted Glu 14, Ala 1, and Trp 3 residues. The combined findings are consistent with the proposal that stabilization of the N‐terminal residues inhibits the β‐sheet from “unzipping” at elevated temperatures (Blake, P.R., Park, J.‐B., Bryant, F.O., et al., 1991, Biochemistry 30, 10885–10895). In view of the high structural similarities between this hyperthermophilic protein and C. pasteurianum Rd, this effect may serve as the dominant mechanism by which P. furiosus Rd is stabilized at high temperatures.
The terms MSC and MSCs have become the preferred acronym to describe a cell and a cell population of multipotential stem/progenitor cells commonly referred to as mesenchymal stem cells, ...multipotential stromal cells, mesenchymal stromal cells, and mesenchymal progenitor cells. The MSCs can differentiate to important lineages under defined conditions in vitro and in limited situations after implantation in vivo. MSCs were isolated and described about 30 years ago and now there are over 55,000 publications on MSCs readily available. Here, we have focused on human MSCs whenever possible. The MSCs have broad anti-inflammatory and immune-modulatory properties. At present, these provide the greatest focus of human MSCs in clinical testing; however, the properties of cultured MSCs in vitro suggest they can have broader applications. The medical utility of MSCs continues to be investigated in over 950 clinical trials. There has been much progress in understanding MSCs over the years, and there is a strong foundation for future scientific research and clinical applications, but also some important questions remain to be answered. Developing further methods to understand and unlock MSC potential through intracellular and intercellular signaling, biomedical engineering, delivery methods and patient selection should all provide substantial advancements in the coming years and greater clinical opportunities. The expansive and growing field of MSC research is teaching us basic human cell biology as well as how to use this type of cell for cellular therapy in a variety of clinical settings, and while much promise is evident, careful new work is still needed.
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