364 research outputs found
Cerebral venous thrombosis: a changing landscape
Cerebral venous thrombosis (CVT) is an uncommon cause of stroke and is mainly a disease of the young. The aims of the study were to summarize the change in the clinical profile of CVT and provide an update regarding the current management of the same. A literature search was conducted using Pubmed and Google scholar using the desired terms. Studies were analysed and review was formulated. The median age of CVT in most studies was 32 years. There has been a shift from female pre-ponderence to equal gender predilection. Several studies are confirming the efficacy of D-dimer as a diagnostic marker of CVT. Newer oral anticoagulants have been found to be as efficient as warfarin. There have been several cases of CVT reported in association with COVID-19. This review confirmed the traditional understanding of age and risk factors of CVT. It also noted a change from the female pre-ponderence. NOACS are emerging as the preferred drug for the long-term management of CVT
A study of prevalence of peripheral neuropathy in patients with impaired glucose tolerance
Background: It is estimated that about half of the diabetics develop diabetic peripheral neuropathy (DPN). Prediabetes is the precursor of type 2 diabetes and it is projected that by 2045 nearly 8.6% of the global adult population may be affected by prediabetes. Pre diabetics also shares the vascular complications of diabetes. Evaluation of impaired glucose tolerance (IGT) and its association with neuropathy is hence very essential. According to International Diabetes Federation, number of global impaired glucose regulation (IGR) patients will reach 471 million by 2035. It is imperative that management strategies aimed at timely diagnosis and prevention of these complications be framed.Methods: 30 patients with IGT were recruited from outpatient/inpatient department of JSS hospital who met the following WHO diagnostic criteria (HbA1C of 5.7-6.4%, fasting blood sugar of 100-125 mg/dl, oral glucose tolerance test (OGTT) 2-hour blood sugar of 140-199 mg/dl) were included in the study. All the patients underwent nerve conduction studies as per the established clinical practice and results were compared with the standard values of our laboratory.Results: 13 patients (43.33%) had neuropathy based on nerve conduction studies (NCS). Sensory neuropathy (53.85%) was most common followed by motor and mixed types with 3 patients each (23.08%).Conclusions: Prevalence of neuropathy was high in prediabetics. Small fibre involvement as manifested by sensory component was predominant in our study. Family history of diabetes was an important risk factor associated with higher neuropathy prevalence.
Study of insulin resistance as an inflammatory marker for ischemic stroke severity among non-diabetics
Background: Insulin resistance (IR) is emerging as an important modifiable risk factor causing acute ischemic stroke. The purpose of the study was to evaluate insulin resistance among patients of acute ischemic stroke, in non-diabetic patients, and to correlate insulin resistance with the severity of acute ischemic stroke, and to observe its association with traditional risk factors.
Methods: It was a prospective study conducted at JSS Medical College, Mysore, India from September 2021 to December 2022. Patients who presented with the history of stroke, who were non-diabetics and aged >18 years were included with informed consent. Ischemic stroke was diagnosed with clinical findings and by neuroimaging. Stroke severity was assessed by NIHSS score. Homeostasis model assessment (HOMA) was used to estimate insulin resistance and the levels were studied in relation to the stroke severity.
Results: A total of 127 non-diabetic ischemic stroke patients were enrolled in the study. Hyperinsulinemia, i.e. serum insulin >9 μU/mL, was observed in 44 (34.64%) patients. IR with HOMA-IR ≥2.5 was noted in 39 (30.7%) patients. NIHSS score in severity (group III) was strongly associated with serum insulin >9 μU/mL (62.1%) (P = 0.001) and HOMA-IR ≥2.5 (62.1%) (P<0.0001).
Conclusions: Screening for insulin resistance in nondiabetic patients with ischemic stroke may identify those who are at higher risk for poor outcomes, allowing for early intervention and closer monitoring. Also, interventions to reduce insulin resistance, such as lifestyle modifications or medications, may be beneficial in improving stroke outcomes
Neuropathy in the setting of alcoholism-an entity less thought of
Disulfiram is a commonly used adjunctive treatment in the management of alcohol dependency. It has been noted that disulfiram can induce peripheral neuropathy, the mechanism of which has not been clearly determined. A 35-year-old patient, reformed alcoholic, on disulfiram presented with complaints of painful distal dysesthesias and foot drop. Clinical examination revealed bilateral foot drop without any objective sensory loss. Patient was evaluated for the same and routine blood investigations including vitamin B-12, inflammatory and virological markers were found to be normal. Nerve conductions studies revealed in excitable bilateral common peroneal and tibial nerves. Possibility of disulfiram induced peripheral neuropathy was thought of and drug was withdrawn. Patient was followed up and after two months improvement in motor power and reduction in paraesthesia’s was noted. Disulfiram is a commonly used drug, the uncommon side effect of which is distal predominant axonal neuropathy. This must be kept be kept in mind when evaluating a patient presenting with features of peripheral neuropathy, on a background of alcohol abuse
Zero Temperature Dynamics of 2D and 3D Ising Ferromagnets
We consider zero-temperature, stochastic Ising models with nearest-neighbor
interactions in two and three dimensions. Using both symmetric and asymmetric
initial configurations, we study the evolution of the system with time. We
examine the issue of convergence of the dynamics and discuss the nature of the
final state of the system. By determining a relation between the median number
of spin flips per site, the probability p that a spin in the initial spin
configuration takes the value +1, and lattice size, we conclude that in two and
three dimensions, the system converges to a frozen (but not necessarily
uniform) state when p is not equal to 1/2. Results for p=1/2 in three
dimensions are consistent with the conjecture that the system does not evolve
towards a fully frozen limiting state. Our simulations also uncover `striped'
and `blinker' states first discussed by Spirin et al., and their statistical
properties are investigated.Comment: 17 pages, 12 figure
Ising Ferromagnet: Zero-Temperature Dynamic Evolution
The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a
square lattice is followed by Monte Carlo computer simulations. The system
always eventually reaches a final, absorbing state, which sometimes coincides
with a ground state (all spins parallel), and sometimes does not (parallel
stripes of spins up and down). We initiate here the numerical study of
``Chaotic Time Dependence'' (CTD) by seeing how much information about the
final state is predictable from the randomly generated quenched initial state.
CTD was originally proposed to explain how nonequilibrium spin glasses could
manifest equilibrium pure state structure, but in simpler systems such as
homogeneous ferromagnets it is closely related to long-term predictability and
our results suggest that CTD might indeed occur in the infinite volume limit.Comment: 14 pages, Latex with 8 EPS figure
Directional emission of light from a nano-optical Yagi-Uda antenna
The plasmon resonance of metal nanoparticles can enhance and direct light
from optical emitters in much the same way that radio frequency (RF) antennas
enhance and direct the emission from electrical circuits. In the RF regime, a
typical antenna design for high directivity is the Yagi-Uda antenna, which
basically consists of a one-dimensional array of antenna elements driven by a
single feed element. Here, we present the experimental demonstration of
directional light emission from a nano-optical Yagi-Uda antenna composed of an
array of appropriately tuned gold nanorods. Our results indicate that
nano-optical antenna arrays are a simple but efficient tool for the spatial
control of light emission.Comment: 4 pages, including 4 figure
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Sialoglycan recognition is a common connection linking acidosis, zinc, and HMGB1 in sepsis
© 2021 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY). https://creativecommons.org/licenses/by/4.0/Blood pH is tightly maintained between 7.35 and 7.45, and acidosis (pH <7.3) indicates poor prognosis in sepsis, wherein lactic acid from anoxic tissues overwhelms the buffering capacity of blood. Poor sepsis prognosis is also associated with low zinc levels and the release of High mobility group box 1 (HMGB1) from activated and/or necrotic cells. HMGB1 added to whole blood at physiological pH did not bind leukocyte receptors, but lowering pH with lactic acid to mimic sepsis conditions allowed binding, implying the presence of natural inhibitor(s) preventing binding at normal pH. Testing micromolar concentrations of divalent cations showed that zinc supported the robust binding of sialylated glycoproteins with HMGB1. Further characterizing HMGB1 as a sialic acid-binding lectin, we found that optimal binding takes place at normal blood pH and is markedly reduced when pH is adjusted with lactic acid to levels found in sepsis. Glycan array studies confirmed the binding of HMGB1 to sialylated glycan sequences typically found on plasma glycoproteins, with binding again being dependent on zinc and normal blood pH. Thus, HMGB1-mediated hyperactivation of innate immunity in sepsis requires acidosis, and micromolar zinc concentrations are protective. We suggest that the potent inflammatory effects of HMGB1 are kept in check via sequestration by plasma sialoglycoproteins at physiological pH and triggered when pH and zinc levels fall in late stages of sepsis. Current clinical trials independently studying zinc supplementation, HMGB1 inhibition, or pH normalization may be more successful if these approaches are combined and perhaps supplemented by infusions of heavily sialylated molecules.Peer reviewe
Metastability in zero-temperature dynamics: Statistics of attractors
The zero-temperature dynamics of simple models such as Ising ferromagnets
provides, as an alternative to the mean-field situation, interesting examples
of dynamical systems with many attractors (absorbing configurations, blocked
configurations, zero-temperature metastable states). After a brief review of
metastability in the mean-field ferromagnet and of the droplet picture, we
focus our attention onto zero-temperature single-spin-flip dynamics of
ferromagnetic Ising models. The situations leading to metastability are
characterized. The statistics and the spatial structure of the attractors thus
obtained are investigated, and put in perspective with uniform a priori
ensembles. We review the vast amount of exact results available in one
dimension, and present original results on the square and honeycomb lattices.Comment: 21 pages, 6 figures. To appear in special issue of JPCM on Granular
Matter edited by M. Nicodem
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Diverging and Converging: Integrative Insights on a Paradox Meta-perspective
Paradox theory stands at an exciting moment in organization and management theory. Scholars increasingly seek out insights about the nature and management of contradictory demands to explain a wide array of organizational phenomena across multiple levels of analysis. Our two reviews in the 2016 Academy of Management Annals attest to this growing breadth and depth, each integrating and expanding related, yet different bodies of research. Schad, Lewis, Raisch, and Smith (2016) emphasize the depth of scholarship by analyzing an increasing number of paradox studies within management science. Putnam, Fairhurst, and Banghart (2016) highlight the breadth of scholarship by comparing paradoxes that emerge from multiple theories and paradigms that embrace an interdisciplinary orientation. By drawing on distinct literatures, these two manuscripts reveal diverse insights and reflections about paradoxical demands in organizations. In this integrative reflection, we juxtapose our two review articles, surface distinct assumptions and emphases, highlight complementarities, and raise questions for future scholarship. In doing so, we hope to fuel insights toward a meta-perspective on paradox
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