RESUMEN

5-lipoxygenase (5-LO) catalyzes the conversion of arachidonic acid (AA) into pro-inflammatory leukotrienes. N-3 PUFA like eicosapentaenoic acid are subject to a similar metabolism and are precursors of pro-resolving mediators. Stearidonic acid (18:4 n-3, SDA) is a plant source of n-3 PUFA that is elongated to 20:4 n-3, an analogue of AA. However, no 5-LO metabolites of 20:4 n-3 have been reported. In this study, control and 5-LO-expressing HEK293 cells were stimulated in the presence of 20:4 n-3. Metabolites were characterized by LC-MS/MS and their anti-inflammatory properties assessed using AA-induced autocrine neutrophil stimulation and leukotriene B4-mediated chemotaxis. 8­hydroxy­9,11,14,17-eicosatetraenoic acid (Δ17-8-HETE) and 8,15-dihydroxy-9,11,13,17-eicosatetraenoic acid (Δ17-8,15-diHETE) were identified as novel metabolites. Δ17-8,15-diHETE production was inhibited by the leukotriene A4 hydrolase inhibitor SC 57461A. Autocrine neutrophil leukotriene stimulation and neutrophil chemotaxis, both BLT1-dependent processes, were inhibited by Δ17-8,15-diHETE at low nM concentrations. These data support an anti-inflammatory role for Δ17-8,15-diHETE, a novel 5-LO product.

Asunto(s)

Antiinflamatorios/metabolismo , Araquidonato 5-Lipooxigenasa/metabolismo , Ácidos Hidroxieicosatetraenoicos/biosíntesis , Leucotrieno B4/biosíntesis , Neutrófilos/enzimología , Ácido Araquidónico/metabolismo , Ácido Eicosapentaenoico/análogos & derivados , Ácido Eicosapentaenoico/metabolismo , Femenino , Células HEK293 , Humanos , Masculino

RESUMEN

This paper presents the irradiation and processing of high-current 100Mo targets at the University of Alberta (UofA) in a GMP compliant setting. For purpose of comparison with a second production facility, additional studies at Centre Hospitalier Universitaire de Sherbrooke (CHUS) are also described. INTRODUCTION: More than 70% of today's diagnostic radiopharmaceuticals are based on 99mTc, however the conventional supply chain for obtaining 99mTc is fragile. The aim of this work was to demonstrate reliable high yield production and processing of 99mTc with medium-energy, high-current, cyclotrons. METHODS: We used two cyclotrons (TR-24, Advanced Cyclotron Systems, Inc) for irradiations with 22 MeV or 24 MeV incident energy and 400 µA current up to a maximum of 6 h. The irradiated 100Mo was dissolved using peroxide, basified using ammonium carbonate, and purified using a PEG-based solid phase extraction technique. RESULTS: High-yield productions with 22 MeV (400 µA, 6 h) yielded an average isolated [99mTc]TcO4- yield of 878 GBq ±â€¯99 GBq (23.7 Ci ±â€¯2.7 Ci) decay corrected to EOB, n = 8 (isolated saturation yield: 4.36 ±â€¯0.49 GBq/µA). Irradiations with 24 MeV (400 µA, 6 h) resulted in an average isolated [99mTc]TcO4- yield of 993 GBq ±â€¯100 GBq (26.8 Ci ±â€¯2.7 Ci) decay corrected to EOB, n = 7 (isolated saturation yield: 4.97 ±â€¯0.50 GBq/µA). These yields corresponds to 600-700 GBq (16-19 Ci) of [99mTc]TcO4- at release (i.e. 3 hour post-EOB). For all tested batches, the QC results were within the recently published specifications in the European Pharmacopoeia. CONCLUSION: Reliable near-TBq production yields for 99mTc can be obtained using medium-energy cyclotrons. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: This work presents evidence that medium-energy high-current cyclotrons can provide high yields of [99mTc]TcO4- with radionuclidic impurities levels within the specifications of the existing European Pharmacopoeia monograph, indicating that this technology can have a share in the future 99mTc supply market.

Asunto(s)

Ciclotrones , Radioquímica/instrumentación , Pertecnetato de Sodio Tc 99m/química , Endotoxinas/análisis

RESUMEN

Hydrophobic adsorbents such as C18 and C30 were coated with PEG and subsequently used for the separation of Mo/Tc. The most effective resin for adsorbing PEG was the C18-U resin, which demonstrated a coating capacity of 97.6±2.8mg PEG per g of resin. The ability to adsorb pertechnetate was proportional to the amount of PEG coated on the hydrophobic resin. The [(99m)Tc]pertechnetate recovery during the separation of cyclotron produced (99m)Tc from (100)Mo was 91.8±0.3% (n=2). The resultant product met relevant USP monograph specifications.

Asunto(s)

Molibdeno/aislamiento & purificación , Pertecnetato de Sodio Tc 99m/aislamiento & purificación , Adsorción , Ciclotrones , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Isótopos/aislamiento & purificación , Polietilenglicoles , Radioisótopos/aislamiento & purificación , Radiofármacos/aislamiento & purificación , Resinas Sintéticas

RESUMEN

Obstructive sleep apnea (OSA) is characterised by repetitive cessation or reduction of airflow due to upper airway obstructions. These respiratory events lead to chronic sleep fragmentation and intermittent hypoxemia. Several studies have shown that OSA is associated with daytime sleepiness and cognitive dysfunctions, characterized by impairments of attention, episodic memory, working memory, and executive functions. This paper reviews the cognitive profile of adults with OSA and discusses the relative role of altered sleep and hypoxemia in the aetiology of these cognitive deficits. Markers of cognitive dysfunctions such as those measured with waking electroencephalography and neuroimaging are also presented. The effects of continuous positive airway pressure (CPAP) on cognitive functioning and the possibility of permanent brain damage associated with OSA are also discussed. Finally, this paper reviews the evidence suggesting that OSA is a risk factor for developing mild cognitive impairment and dementia in the aging population and stresses the importance of its early diagnosis and treatment.

Asunto(s)

Trastornos del Conocimiento/etiología , Apnea Obstructiva del Sueño/psicología , Adulto , Anciano , Atención/fisiología , Daño Encefálico Crónico/etiología , Daño Encefálico Crónico/fisiopatología , Daño Encefálico Crónico/prevención & control , Trastornos del Conocimiento/fisiopatología , Trastornos del Conocimiento/prevención & control , Comorbilidad , Presión de las Vías Aéreas Positiva Contínua , Demencia/etiología , Demencia/fisiopatología , Demencia/prevención & control , Trastornos de Somnolencia Excesiva/etiología , Trastornos de Somnolencia Excesiva/prevención & control , Electroencefalografía , Potenciales Evocados , Función Ejecutiva/fisiología , Femenino , Humanos , Hipoxia/etiología , Hipoxia/prevención & control , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/prevención & control , Persona de Mediana Edad , Neuroimagen , Desempeño Psicomotor/fisiología , Factores de Riesgo , Apnea Obstructiva del Sueño/complicaciones , Apnea Obstructiva del Sueño/diagnóstico , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/fisiopatología , Apnea Obstructiva del Sueño/terapia , Privación de Sueño/etiología , Privación de Sueño/psicología , Ronquido/etiología

RESUMEN

There is growing interest in the large scale cyclotron production of (99m)Tc via the (100)Mo(p,2n)(99m)Tc reaction. While the use and recycling of cyclotron-irradiated enriched molybdenum targets has been reported previously in the context of (94m)Tc production, to the best of our knowledge, previous recycling studies have been limited to the use of oxide targets. To facilitate reuse of high-power enriched (100)Mo targets, this work presents and evaluates a strategy for recycling of enriched metallic molybdenum. For the irradiated (100)Mo targets in this study, an overall metal to metal recovery of 87% is reported. Evaluation of "new" and "recycled" (100)Mo revealed no changes in the molybdenum isotopic composition (as measured via ICP-MS). For similar irradiation conditions of "new" and "recycled" (100)Mo, (i.e. target thicknesses, irradiation time, and energy), comparable levels of (94g)Tc, (95g)Tc, and (96g)Tc contaminants were observed. Comparable QC specifications (i.e. aluminum ion concentration, pH, and radiochemical purity) were also reported. We finally note that [(99m)Tc]-MDP images obtained by comparing MDP labelled with generator-based (99m)Tc vs. (99m)Tc obtained following the irradiation of recycled (100)Mo demonstrated comparable biodistribution. With the goal of producing large quantities of (99m)Tc, the proposed methodology demonstrates that efficient recycling of enriched metallic (100)Mo targets is feasible and effective.

RESUMEN

As water-soluble ionic contaminants, which arise following proton irradiation of [18O]H2O have been associated with decreased [18F]FDG yields, the minimization of these contaminants is an asset in improving the [18F]F reactivity. To this end, we have previously demonstrated that the use of Nb-sputtered Havar foils results in decreased radionuclidic and chemical impurities in proton irradiated [18O]H2O, improved [18F]FDG yields, and improved [18F]FDG yield consistency when compared with non-sputtered Havar. Resulting from the highly reactive chemical microenvironment within the target however, this niobium layer is observed to degrade over time. To find a material that displays increased longevity with regards to maintaining high [18F]F reactivity, this project extensively investigated and compared Havar foils sputtered with Nb, Pt, Ta, Ti, Zr and ZrO2. Of the materials investigated, the results of this study suggest that Ta-sputtered Havar foil is the preferred choice. For similar integrated currents (~1,000,000 µA min), when comparing the Ta-sputtered Havar with Nb-sputtered Havar we observed: (i) greater than an order of magnitude decrease in radionuclidic impurities, (ii) a 6.4 percent increase (p=0.0025) in the average TracerLab MX [18F]FDG yield, and (iii) an overall improvement in the FDG yield consistency. Excellent performance of the Ta-sputtered foil was maintained throughout its ~1,500,000 µA min lifetime.

Asunto(s)

Fluorodesoxiglucosa F18/síntesis química , Niobio/química , Platino (Metal)/química , Tantalio/química , Circonio/química , Ciclotrones , Fluorodesoxiglucosa F18/química , Fluorodesoxiglucosa F18/aislamiento & purificación , Microscopía Electrónica de Rastreo , Protones , Titanio , Agua

RESUMEN

Reversible phosphorylation by protein kinases is probably one of the most important examples of post-translational modification of ion transport proteins. Ste20-related proline alanine-rich kinase (SPAK) and oxidative stress response kinase (OSR1) are two serine/threonine kinases belonging to the germinal centre-like kinase subfamily VI. Genetic analysis suggests that OSR1 evolved first, with SPAK arising following a gene duplication in vertebrate evolution. SPAK and OSR1 are two recently discovered kinases which have been linked to several key cellular processes, including cell differentiation, cell transformation and proliferation, cytoskeleton rearrangement, and most recently, regulation of ion transporters. Na-K-2Cl cotransporter activity is regulated by phosphorylation. Pharmacological evidence has identified several kinases and phosphatases which alter cotransporter function, however, no direct linkage between these enzymes and the cotransporter has been demonstrated. This article will review some of the physical and physiological properties of SPAK and OSR1, and present new evidence of a direct interaction between the Na-K-Cl cotransporter and the stress kinases.

Asunto(s)

Canales de Cloruro/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Membrana Celular/metabolismo , Activación Enzimática , Humanos , Transporte Iónico , Proteínas Serina-Treonina Quinasas/genética , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Estrés Fisiológico/fisiología , Distribución Tisular

RESUMEN

The efficacy of clinical islet transplantation has been demonstrated with autografts, and although islet allografts have established insulin independence in a small number of IDDM patients, the treatment is confounded by the necessity of immunosuppression. the lack of donor tissue, and recurring islet immunogenicity. These limitations underscore a need to develop therapies to serve the large population of diabetic patients. Porcine islet xenotransplantation, together with a successful immune intervention strategy, may provide the necessary clinical alternative. However, a major obstacle in evaluating this approach has been the difficulty of obtaining adequate volumes of functional islet tissue from pigs. Donors of market weight are preferable to retired breeders due to their abundance, lower animal and husbandry costs. and are more suitable to meet regulatory guidelines for donor tissue for xenotransplantation. We describe a simple isolation procedure that following purification yields a mean of 350,000 IE, corresponding to 179 units of insulin and 1.8 mg of DNA with an islet purity and viability in excess of 85% (n = 317 isolations). In both short- and long-term cell cultures, porcine islets demonstrated glucose-responsive insulin secretion. However, this secretion is density dependent, which may have significant consequences in the development of immunoisolation technologies to support porcine islet xenotransplantation. Following implantation into diabetic nude mice, porcine islets remained functional in excess of 1 year. Implantation of a bioartificial pancreas containing porcine islets into pancreatectomized dogs provided significant clinical benefit with an improved diabetic condition. Finally, secretagogue-induced insulin release was demonstrated in vitro from these devices after removal from immunocompetent recipients. Immunohistochemical staining identified well-granulated islets following long-term implantation in both the rodent and canine models. This study demonstrates the ability to isolate porcine islets in clinically relevant numbers from market animals, which survive and remain functional for prolonged periods of time in an immune-deficient or immunoprotected environment.

Asunto(s)

Trasplante de Islotes Pancreáticos , Islotes Pancreáticos/citología , Islotes Pancreáticos/fisiología , Páncreas Artificial , Animales , Peso Corporal , Separación Celular , Células Cultivadas , Diabetes Mellitus Tipo 1/cirugía , Perros , Femenino , Glucosa/farmacología , Insulina/metabolismo , Secreción de Insulina , Islotes Pancreáticos/efectos de los fármacos , Masculino , Estimulación Química , Porcinos , Trasplante Heterólogo

RESUMEN

Coupled K and Cl movements are mediated by several isoforms of the K-Cl cotransporter (COT) encoded by the KCC genes. The ubiquitous KCC1 isoform, important for cell volume and ion homeostasis, has 12 transmembrane domains (Tmds), and cytoplasmic N- and C-terminal domains (Ntd and Ctd). This study investigates the cellular localization of KCC1 by confocal microscopy, activation of K-Cl COT by various non-osmotic and osmotic interventions with net unidirectional K and Rb fluxes at 37( degrees )C, and the effect of Ctd deletion on K-Cl COT regulation. Human embryonic kidney (HEK293) cells were transfected with full-length (fl) rabbit (rb)KCC1 and - CtdKCC1 cDNAs obtained after truncation at nucleotide 2011. Normal cells exposed to polyclonal anti-Ctd antibodies against Ctd epitopes within a 77 amino acid sequence (a.a.943-1020) revealed granular membrane and cytoplasmic immunostaining, presumably endogenous KCC1. Additional diffuse membrane and cytoplasmic immunofluorescence in flKCC1-transfected cells was absent in -CtdKCC1-transfected cells. Monoclonal antibodies against a c-myc epitope at the protein Ntd showed both membrane and cytosolic fluorescence. Basal and N-ethylmaleimide (NEM)-stimulated Rb influxes through K-Cl COT, calculated as Cl-dependent Rb fluxes, were 2-3-fold higher in flKCC1-transfected than in normal cells. NEM stimulation of K-Cl COT was highest in flKCC1-transfected cells, significantly lower in stably and abrogated in transiently -CtdKCC1-transfected cells. Furosemide, calyculin and genistein inhibited basal and NEM-stimulated K-Cl COT in normal and transfected cells. Staurosporine and hydroxylamine were ineffective stimulators. No effect of pH(0) changes (6.3-8.4) was observed in basal or NEM-stimulated K-Cl COT, in both normal and transfected cells. However, inhibition by NEM occurred at pH(0) 8.4. Furthermore, in a Cl-independent manner, NEM lowered cell K content by >30% and hypotonicity (210-70mOsM) stimulated furosemide-sensitive Rb influx and K loss. Thus, in cultured normal and KCC1-transfected cells, K-Cl COT shows significant differences from erythrocytes, and NEM and cell swelling open furosemide-sensitive and Cl-independent K/Rb channels. Failure of K-Cl COT in cells transfected with Ctd-truncated KCC1 to respond to NEM suggests a role of the Ctd for signal transduction.

Asunto(s)

Proteínas Portadoras/metabolismo , Cloruros/metabolismo , Riñón/metabolismo , Potasio/metabolismo , Simportadores , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/genética , ADN Complementario , Etilmaleimida/farmacología , Furosemida/farmacología , Genisteína/farmacología , Humanos , Concentración de Iones de Hidrógeno , Inmunohistoquímica , Transporte Iónico , Riñón/citología , Riñón/efectos de los fármacos , Riñón/embriología , Microscopía Confocal , Microscopía Fluorescente , Concentración Osmolar , Oxazoles/farmacología , Rubidio/metabolismo , Transfección , Cotransportadores de K Cl

RESUMEN

Part I of this article (J Can Dent Assoc 65:394-8) looked at the application of guided tissue regeneration (GTR) in endodontics, the mechanisms of action of GTR and its various presentations. Part II examines the technique for surgically inserting a membrane for GTR, based on a review of the current literature.

Asunto(s)

Regeneración Tisular Guiada Periodontal , Tratamiento del Conducto Radicular , Absorción , Regeneración Tisular Guiada Periodontal/efectos adversos , Humanos , Membranas Artificiales

RESUMEN

Over the past twenty years, Guided Tissue Regeneration (GTR) has become an accepted technique for the treatment of tissue loss consequent to periodontal disease. The principles of GTR have recently begun to be employed in endodontics since pulpal necrosis often leads to periodontal tissue loss as a result of the leakage of noxious irritants through apical foramina and accessory canals. This treatment modality is still in its early days for the management of endo-perio lesions and is most appropriately used in specific types of cases. This article, the first of a two-part series, presents a review of the literature about the mechanisms of action of GTR and discusses some of the products used to bring about GTR.

Asunto(s)

Regeneración Tisular Guiada Periodontal , Periodontitis Periapical/cirugía , Necrosis de la Pulpa Dental/complicaciones , Humanos , Membranas Artificiales , Periodontitis Periapical/etiología , Tratamiento del Conducto Radicular/métodos

RESUMEN

BACKGROUND: Idiopathic myelofibrosis (IMF) is a bone marrow and hematologic disorder. Retinal and systemic manifestations are observed and result from inefficient blood cell production and blood cell irregularities. CASE REPORT: A review of IMF as a disease process is presented by way of case report. A 70-year-old woman came to us with specific systemic symptoms. Further ocular investigation revealed bilateral retinal hemorrhages. The hemorrhages were consistent with the results of subsequently ordered blood tests. An understanding of the underlying systemic condition and recognition of the retinal manifestations of IMF aid in the diagnosis. Recognizing differential diagnoses is important as well because IMF produces retinal findings similar to other blood disorders with comparable blood counts and morphologies. There are certain systemic signs the optometrist may look for to assist in the recognition of IMF as opposed to the other diseases. CONCLUSION: This is an important disease process to recognize, since the systemic and retinal manifestations are within optometry's scope to co-manage.

Asunto(s)

Mielofibrosis Primaria/complicaciones , Hemorragia Retiniana/etiología , Anciano , Diagnóstico Diferencial , Femenino , Humanos , Mielofibrosis Primaria/diagnóstico por imagen , Hemorragia Retiniana/diagnóstico , Tomografía Computarizada por Rayos X

RESUMEN

This clinical study was performed to evaluate the advantages and limitations of 3 acoustic stethoscopes and 3 electronic stethoscopes. It shows that it is possible to design a new electronic stethoscope by considering the advantages of both the acoustic and electronic stethoscopes.

Asunto(s)

Estetoscopios , Acústica , Electrónica Médica , Diseño de Equipo , Humanos

Asunto(s)

MEDLINE/normas , Publicaciones Periódicas como Asunto , Descriptores , Humanos