New stationary phases for efficient separations and selectivity studies in anion chromatography

Spacer arm anion-exchange resins for single-column ion chromatography (SCIC) were prepared by a two-step procedure consisting of a bromoalkylation of Rohm & Haas XAD-1 resin under mild conditions, followed by amination with trimethylamine. The five resins prepared are all of a similar, low capacity and contain a one-, two-, three-, four- or six-carbon spacer arm linkage between the resin surface and the quaternary ammonium exchange group. The selectivity of these resins for mono- and divalent anions is evaluated and explained using classical ion-exchange theory. Separations are presented to demonstrate resin selectivity and to show the usefulness of these resins for practical ion chromatography;Trimethylammonium, tributylammonium and tributylphosphonium anion-exchange resins were synthesized and used for SCIC. The three resins were prepared using a 7 to 12 [mu]m polystyrene-divinylbenzene resin and are all of a similar, low capacity. The selectivity of these resins for mono- and divalent anions is examined and related to classical theory. It is shown that the unique selectivity obtained with the quaternary phosphonium resin is of practical value in the separation of anions;A new stationary phase for anion chromatography was prepared by a simple method of coating quaternized latex particles onto the surface of unsulfonated polymeric resins. A nonporous polystyrene resin of very uniform particle size is described that serves as an excellent substrate for the coated resins. These latex-coated resins are used to obtain highly efficient anion separations

Distinct Mitochondrial Pathologies Caused by Mutations of the Proximal Tubular Enzymes EHHADH and GATM

The mitochondria of the proximal tubule are essential for providing energy in this nephron segment, whose ATP generation is almost exclusively oxygen dependent. In addition, mitochondria are involved in a variety of metabolic processes and complex signaling networks. Proximal tubular mitochondrial dysfunction can therefore affect renal function in very different ways. Two autosomal dominantly inherited forms of renal Fanconi syndrome illustrate how multifaceted mitochondrial pathology can be: Mutation of EHHADH, an enzyme in fatty acid metabolism, results in decreased ATP synthesis and a consecutive transport defect. In contrast, mutations of GATM, an enzyme in the creatine biosynthetic pathway, leave ATP synthesis unaffected but do lead to mitochondrial protein aggregates, inflammasome activation, and renal fibrosis with progressive renal failure. In this review article, the distinct pathophysiological mechanisms of these two diseases are presented, which are examples of the spectrum of proximal tubular mitochondrial diseases

Multi-frequency study of DEM L299 in the Large Magellanic Cloud

We have studied the HII region DEM L299 in the Large Magellanic Cloud to understand its physical characteristics and morphology in different wavelengths. We performed a spectral analysis of archived XMM-Newton EPIC data and studied the morphology of DEM L299 in X-ray, optical, and radio wavelengths. We used H alpha, [SII], and [OIII] data from the Magellanic Cloud Emission Line Survey and radio 21 cm line data from the Australia Telescope Compact Array (ATCA) and the Parkes telescope, and radio continuum data from ATCA and the Molonglo Synthesis Telescope. Our morphological studies imply that, in addition to the supernova remnant SNR B0543-68.9 reported in previous studies, a superbubble also overlaps the SNR in projection. The position of the SNR is clearly defined through the [SII]/H alpha flux ratio image. Moreover, the optical images show a shell-like structure that is located farther to the north and is filled with diffuse X-ray emission, which again indicates the superbubble. Radio 21 cm line data show a shell around both objects. Radio continuum data show diffuse emission at the position of DEM L299, which appears clearly distinguished from the HII region N 164 that lies south-west of it. We determined the spectral index of SNR B0543-68.9 to be alpha=-0.34, which indicates the dominance of thermal emission and therefore a rather mature SNR. We determined the basic properties of the diffuse X-ray emission for the SNR, the superbubble, and a possible blowout region of the bubble, as suggested by the optical and X-ray data. We obtained an age of 8.9 (3.5-18.1) kyr for the SNR and a temperature of 0.64 (0.44-1.37) keV for the hot gas inside the SNR, and a temperature of the hot gas inside the superbubble of 0.74 (0.44-1.1) keV. We conclude that DEM L299 consists of a superposition of SNR B0543-68.9 and a superbubble, which we identified based on optical data.Comment: Accepted for publication in Astronomy and Astrophysics. 17 pages, 16 figure

A genetic algorithm-Bayesian network approach for the analysis of metabolomics and spectroscopic data: application to the rapid detection of Bacillus spores and identification of Bacillus species

Background The rapid identification of Bacillus spores and bacterial identification are paramount because of their implications in food poisoning, pathogenesis and their use as potential biowarfare agents. Many automated analytical techniques such as Curie-point pyrolysis mass spectrometry (Py-MS) have been used to identify bacterial spores giving use to large amounts of analytical data. This high number of features makes interpretation of the data extremely difficult We analysed Py-MS data from 36 different strains of aerobic endospore-forming bacteria encompassing seven different species. These bacteria were grown axenically on nutrient agar and vegetative biomass and spores were analyzed by Curie-point Py-MS. Results We develop a novel genetic algorithm-Bayesian network algorithm that accurately identifies sand selects a small subset of key relevant mass spectra (biomarkers) to be further analysed. Once identified, this subset of relevant biomarkers was then used to identify Bacillus spores successfully and to identify Bacillus species via a Bayesian network model specifically built for this reduced set of features. Conclusions This final compact Bayesian network classification model is parsimonious, computationally fast to run and its graphical visualization allows easy interpretation of the probabilistic relationships among selected biomarkers. In addition, we compare the features selected by the genetic algorithm-Bayesian network approach with the features selected by partial least squares-discriminant analysis (PLS-DA). The classification accuracy results show that the set of features selected by the GA-BN is far superior to PLS-DA

Trends in Acromioplasty Utilization During Arthroscopic Rotator Cuff Repair: An Epidemiological Study of 139,586 Patients

INTRODUCTION: Acromioplasty remains very common during rotator cuff repair (RCR) despite limited evidence of clinical efficacy. This study observed the incidence of acromioplasty from 2010 to 2018 in Texas using a publicly available database. METHODS: A total of 139,586 records were analyzed from the Texas Healthcare Information Collection database ranging from 2010 to 2018. These cases were divided into those with and without acromioplasty (N = 107,427 and N = 32,159, respectively). Acromioplasty use was standardized as the number of acromioplasties per RCR (acromioplasty rate). Two subgroup analyses were conducted: surgical institution type and payor status. RESULTS: In 2010, acromioplasty occurred in 84% of all RCR cases with nearly continuous decline to 74% by 2018 (P \u3c 0.001). All subgroups followed this pattern except teaching hospitals which displayed insignificant change from 2010 to 2018 (P = 0.99). The odds of receiving acromioplasty in patients with neither Medicare nor Medicaid was higher than those with Medicare or Medicaid coverage (odds ratio = 1.36, P \u3c 0.001). DISCUSSION: Overall acromioplasty rates decreased modestly, but markedly, beginning in 2012. Despite this small decrease in acromioplasty rate, it remains a commonly performed procedure in conjunction with RCR. Both the academic status of the surgical facility and the payor status of the patient affect the acromioplasty rate

Aquaporins: important but elusive drug targets.

The aquaporins (AQPs) are a family of small, integral membrane proteins that facilitate water transport across the plasma membranes of cells in response to osmotic gradients. Data from knockout mice support the involvement of AQPs in epithelial fluid secretion, cell migration, brain oedema and adipocyte metabolism, which suggests that modulation of AQP function or expression could have therapeutic potential in oedema, cancer, obesity, brain injury, glaucoma and several other conditions. Moreover, loss-of-function mutations in human AQPs cause congenital cataracts (AQP0) and nephrogenic diabetes insipidus (AQP2), and autoantibodies against AQP4 cause the autoimmune demyelinating disease neuromyelitis optica. Although some potential AQP modulators have been identified, challenges associated with the development of better modulators include the druggability of the target and the suitability of the assay methods used to identify modulators

Increasing Rates of Ulnar Collateral Ligament Repair Outpace Reconstruction in Isolated Injuries: Review of a Texas Surgical Database

BACKGROUND: The gold standard of treatment for ulnar collateral ligament (UCL) injuries has been reconstruction. Despite early repair studies yielding less than satisfactory results, there has been recent renewed interest in UCL repair due to improved outcomes and new technologies. Data regarding clinical use of these procedures are lacking. The purpose of this study was to define the epidemiological trends of UCL repair and reconstruction surgery from 2010 to 2019, compare demographic characteristics of patients undergoing either procedure, and determine incidence of concomitant procedures in each surgical group as well as comparing respective patient-level charges. METHODS: A retrospective database analysis of UCL surgeries was performed through the Texas Healthcare Information Collection database, a comprehensive and publicly available statewide billing dataset. Inclusion criteria were defined using Current Procedural Terminology billing codes for elbow UCL repair and reconstruction between 2010 through 2019, excluding patients who had concomitant elbow fractures or lateral collateral ligament tears indicative of high-energy trauma. Procedural volume changes, patient demographics, and commonly performed concomitant procedures including elbow arthroscopy, ulnar nerve surgery, and platelet-rich plasma injection were compared. Total patient-level charges were compared across groups. RESULTS: A total of 1664 patients were included, consisting of 484 UCL repairs and 1180 reconstructions. Total UCL surgeries increased eleven-fold when corrected for population growth from 2010 (N = 25) to 2019 (N = 315). In 2010, repair constituted 23% of all UCL tear surgeries and increased to 40% by the end of 2019. The annual frequency of UCL repair increased at a 5.4% faster rate than UCL reconstruction from 2010 to 2019 ( CONCLUSION: While reconstruction remains more common, the annual frequency of UCL repair is increasing at a faster rate. Since were no demographic differences aside from surgical setting, it can be inferred that patients who were previously receiving reconstruction are instead undergoing repair. This highlights the need for future studies to further identify surgical indications for the two interventions

Regulation of Kir4.1 expression in astrocytes and astrocytic tumors: a role for interleukin-1 beta

<p>Abstract</p> <p>Objective</p> <p>Decreased expression of inwardly rectifying potassium (Kir) channels in astrocytes and glioma cells may contribute to impaired K⁺ buffering and increased propensity for seizures. Here, we evaluated the potential effect of inflammatory molecules, such as interleukin-1β (IL-1β) on Kir4.1 mRNA and protein expression.</p> <p>Methods</p> <p>We investigated Kir4.1 (Kcnj10) and IL-1β mRNA expression in the temporal cortex in a rat model of temporal lobe epilepsy 24 h and 1 week after induction of status epilepticus (SE), using real-time PCR and western blot analysis. The U373 glioblastoma cell line and human fetal astrocytes were used to study the regulation of Kir4.1 expression in response to pro-inflammatory cytokines. Expression of Kir4.1 protein was also evaluated by means of immunohistochemistry in surgical specimens of patients with astrocytic tumors (<it>n</it> = 64), comparing the expression in tumor patients with (<it>n</it> = 38) and without epilepsy (<it>n</it> = 26).</p> <p>Results</p> <p>Twenty-four hours after onset of SE, Kir4.1 mRNA and protein were significantly down-regulated in temporal cortex of epileptic rats. This decrease in expression was followed by a return to control level at 1 week after SE. The transient downregulation of Kir4.1 corresponded to the time of prominent upregulation of IL-1β mRNA. Expression of Kir4.1 mRNA and protein in glial cells in culture was downregulated after exposure to IL-1β. Evaluation of Kir4.1 in tumor specimens showed a significantly lower Kir4.1 expression in the specimens of patients with epilepsy compared to patients without epilepsy. This paralleled the increased presence of activated microglial cells, as well as the increased expression of IL-1β and the cytoplasmic translocation of high mobility group box 1 (HMGB1).</p> <p>Conclusions</p> <p>Taken together, these findings indicate that alterations in expression of Kir4.1 occurring in epilepsy-associated lesions are possibly influenced by the local inflammatory environment and in particular by the inflammatory cytokine IL-1β.</p