Synthesis and Characterization of Poly(butylene Oxide) Grafted Carbon Nanofibers

The grafting of polybutylene oxide onto purified and functionalized carbon nanofibers is reported. Grafting was possible after the insertion of 2-(formyloxy)ethyl 2-bromo-2-methylpropanoate onto the carbon nanofibers. The polymerization of tetrahydrofuran was mediated by copper(I) bromide and 1,1,4,7-pentamethyl diethylenetriamine. The polymer-grafted carbon nanofibers were characterized by Raman spectrsocopy, Transmission Electron Microscopy, and Thermogravimetric Analysis. TEM images of CNF-COOH (A), CNF-PBO (B), completely open tip of CNF-COOH, and coated tip of CNF-PBO (D) are shown in the left panel. The right panel depicts the distribution of bromine (blue), and carbon (red) atoms inside and in the vicinity of CNF-Br (as obtained by Electron Energy Loss Spectroscopy). The bottom shows the actual doped CNF. Preliminary data showed that these modified fibers have potential applications as smart (electrorheological) fluids

Facile, Green Synthesis of Large Single Crystal Copper Micro and Nanoparticles with Ascorbic Acid and Gum Arabic

Large single crystal colloidal copper particles with diameters between 0.5 - 2 μm were created using a green synthesis process. The process used ascorbic acid to reduce Schweizer’s reagent created in situ using copper salts in the presence of various concentrations of gum arabic. The Schweizer’s reagents were created by varying the concentrations of ammonium hydroxide and copper nitrate solutions, copper hydroxide, or copper sulfate. The pH of the solution was controlled by the addition of ascorbic acid. Particle formation was favored at high temperature using copper sulfate at pH values ranging from 7.5 to 9, while the optimal formation occurred at a pH value of 8.5. At high concentrations, copper particle formation was found to occur from the aggregation of smaller particles which continued to nucleate once aggregated, and this resulted in the creation of globular particles and large aggregates of micron-sized particles. The addition of gum arabic resulted in the creation of large single crystal particles that did not aggregate. SEM was used to observe the effect of increasing gum arabic concentrations and EDX was used to confirm the elemental purity of the particles

Evolución clínica de la endocarditis infecciosa en pacientes tratados con Meropenem

Introducción: La Endocarditis infecciosa (EI) es una enfermedad grave y potencialmente mortal. En nuestro país existen escasos estudios sobre el uso de Meropenem en estos pacientes.Objetivo: Caracterizar las variables clínico-epidemiológicas en pacientes con diagnóstico de Endocarditis infecciosa tratados con Meropenem.Método: Se realizó un estudio observacional descriptivo, de corte transversal con 41 pacientes con diagnóstico de EI, tratados con Meropenem, en el Hospital Clínico-Quirúrgico ¨Hermanos Ameijeiras¨; en el período comprendido entre enero del 2006 y enero del 2018. Se emplearon estadísticos descriptivos, se calculó la media, desviación estándar y porcientos.Resultados: La edad media fue de 56,6 ± 17,1 años, predominando el grupo de edades de 50 a 69 años (43,9%), la Endocarditis infecciosa en válvula nativa izquierda (43,9) y el Estafilococo como germen más frecuente (43,9%). Se encontró como facto-res predisponentes más vinculados a la EI, la enfermedad valvular adquirida (34,1%) y las prótesis valvulares mecánicas (31,7%); siendo la vía oral la puerta de entrada más frecuente (36,6%). El índice de complicaciones fue elevado (78%), requiriendo trata-miento quirúrgico la mayoría de los pacientes; sin embargo, fue menor el número de fallecidos (26,8%), durante la evolución clínica.Conclusiones: Se encontraron como factores predisponentes más vinculados a la EI, el sexo masculino, la edad entre 50 y 69 años, la enfermedad valvular adquirida y las prótesis valvulares mecánicas; siendo la vía oral la puerta de entrada más frecuente. El índice de complicaciones fue elevado por las características de la muestra estudiada. La mayoría de los pacientes requirió intervención quirúrgica. El tratamiento con meropenem fue beneficioso en el manejo de estos pacientes graves, con menor número de pacientes fallecidos durante la evolución clínica

Essential Role for the C5a Receptor in Regulating the Effector Phase of Synovial Infiltration and Joint Destruction in Experimental Arthritis

A characteristic feature of rheumatoid arthritis is the abundance of inflammatory cells in the diseased joint. Two major components of this infiltrate are neutrophils in the synovial fluid and macrophages in the synovial tissue. These cells produce cytokines including tumor necrosis factor α and other proinflammatory mediators that likely drive the disease through its effector phases. To investigate what mechanisms underlie the recruitment of these cells into the synovial fluid and tissue, we performed expression analyses of chemoattractant receptors in a related family that includes the anaphylatoxin receptors and the formyl-MetLeuPhe receptor. We then examined the effect of targeted disruption of two abundantly expressed chemoattractant receptors, the receptors for C3a and C5a, on arthritogenesis in a mouse model of disease. We report that genetic ablation of C5a receptor expression completely protects mice from arthritis

Cerebral protection in homozygous null ICAM-1 mice after middle cerebral artery occlusion. Role of neutrophil adhesion in the pathogenesis of stroke.

This is the published version. Copyright 1996 American Society for Clinical Research.Acute neutrophil (PMN) recruitment to postischemic cardiac or pulmonary tissue has deleterious effects in the early reperfusion period, but the mechanisms and effects of neutrophil influx in the pathogenesis of evolving stroke remain controversial. To investigate whether PMNs contribute to adverse neurologic sequelae and mortality after stroke, and to study the potential role of the leukocyte adhesion molecule intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of stroke, we used a murine model of transient focal cerebral ischemia consisting of intraluminal middle cerebral artery occlusion for 45 min followed by 22 h of reperfusion. PMN accumulation, monitored by deposition of 111In-labeled PMNs in postischemic cerebral tissue, was increased 2.5-fold in the ipsilateral (infarcted) hemisphere compared with the contralateral (noninfarcted) hemisphere (P < 0.01). Mice immunodepleted of neutrophils before surgery demonstrated a 3.0-fold reduction in infarct volumes (P < 0.001), based on triphenyltetrazolium chloride staining of serial cerebral sections, improved ipsilateral cortical cerebral blood flow (measured by laser Doppler), and reduced neurological deficit compared with controls. In wild-type mice subjected to 45 min of ischemia followed by 22 h of reperfusion, ICAM-1 mRNA was increased in the ipsilateral hemisphere, with immunohistochemistry localizing increased ICAM-1 expression on cerebral microvascular endothelium. The role of ICAM-1 expression in stroke was investigated in homozygous null ICAM-1 mice (ICAM-1 -/-) in comparison with wild-type controls (ICAM-1 +/+). ICAM-1 -/- mice demonstrated a 3.7-fold reduction in infarct volume (P < 0.005), a 35% increase in survival (P < 0.05), and reduced neurologic deficit compared with ICAM-1 +/+ controls. Cerebral blood flow to the infarcted hemisphere was 3.1-fold greater in ICAM-1 -/- mice compared with ICAM-1 +/+ controls (P < 0.01), suggesting an important role for ICAM-1 in the genesis of postischemic cerebral no-reflow. Because PMN-depleted and ICAM-1-deficient mice are relatively resistant to cerebral ischemia-reperfusion injury, these studies suggest an important role for ICAM-1-mediated PMN adhesion in the pathophysiology of evolving stroke

Cc Chemokine Receptor (Ccr)3/Eotaxin Is Followed by Ccr4/Monocyte-Derived Chemokine in Mediating Pulmonary T Helper Lymphocyte Type 2 Recruitment after Serial Antigen Challenge in Vivo

Isolated peripheral blood CD4 cells from allergic individuals express CC chemokine receptor (CCR)3 and CCR4 after expansion in vitro. In addition, human T helper type 2 (Th2) cells polarized in vitro selectively express CCR3 and CCR4 at certain stages of activation/differentiation and respond preferentially to the ligands eotaxin and monocyte-derived chemokine (MDC). However, controversy arises when the in vivo significance of this distinct expression is discussed. To address the functional role of CCR3/eotaxin and CCR4/MDC during the in vivo recruitment of Th2 cells, we have transferred effector Th cells into naive mice to induce allergic airway disease. Tracking of these cells after repeated antigen challenge has established that both CCR3/eotaxin and CCR4/MDC axes contribute to the recruitment of Th2 cells to the lung, demonstrating the in vivo relevance of the expression of these receptors on Th2 cells. We have shown that involvement of the CCR3/eotaxin pathway is confined to early stages of the response in vivo, whereas repeated antigen stimulation results in the predominant use of the CCR4/MDC pathway. We propose that effector Th2 cells respond to both CCR3/eotaxin and CCR4/MDC pathways initially, but that a progressive increase in CCR4-positive cells results in the predominance of the CCR4/MDC axis in the long-term recruitment of Th2 cells in vivo

Clinical features and prognosis of prosthetic valve endocarditis due to Staphylococcus aureus

Purpose: Staphylococcus aureus prosthetic valve endocarditis (SAPVE) is a serious infection with high mortality. The main objective of this study was to identify factors associated with in-hospital mortality. Methods: From January 2008 to December 2021, consecutive patients from a Spanish cohort of infective endocarditis with a definitive diagnosis of SAPVE were analyzed. Results: During the study period, 219 cases of definitive SAPVE were diagnosed, which accounted for 16.7% of a total of 1309 cases of definitive prosthetic valve endocarditis (PVE). Patients presented advanced age and marked comorbidity. There was a higher incidence of persistent bacteremia, septic shock, stroke, and acute kidney injury than in cases of PVE caused by other microorganisms. Methicillin resistance was not associated with differences in clinical presentation, echocardiographic findings, or mortality. Only 50.6% of the patients with surgical indications (88 patients) underwent surgery. Overall, in-hospital mortality was 47.9%. The variables associated with in-hospital mortality were age (OR:1.03, 95% CI: 1.00-1.05; p = 0.016), heart failure (OR:2.86, 95% CI: 1.53–5.32; p = 0.001), acute kidney injury (OR:2.42, 95%CI:1.28–4.58; p = 0.006), stroke (OR:3.53, 95% CI:1.79–6.96; p < 0.001) and surgery indicated but not performed (OR:2.01, 95% CI:1.06–3.8; p = 0.030). On the other hand, the performance of surgery per se in patients with SAPVE, regardless of whether there was a surgical indication according to the guidelines, was not associated with a reduction in in-hospital mortality. Conclusions: SAPVE is characterized by high mortality, which is more marked in patients who present a surgical indication but do not undergo surger