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1.
Front Med (Lausanne) ; 8: 591201, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33869240

RESUMEN

Growing concerns about the safety of long-term opioid therapy and its uncertain efficacy for non-cancer pain have led to relatively rapid opioid deprescribing in chronic pain patients who have been taking opioid for years. To date, empirically supported processes for safe and effective opioid tapering are lacking. Opioid tapering programs have shown high rates of dropouts and increases in patient distress and suicidal ideation. Therefore, safe strategies for opioid deprescribing that are more likely to succeed are urgently needed. In response to this demand, the EMPOWER study has been launched to examine the effectiveness of behavioral medicine strategies within the context of patient-centered opioid tapering in outpatient settings (https://empower.stanford.edu/). The EMPOWER protocol requires an efficient process for ensuring that collaborative opioid tapering would be offered to the most appropriate patients while identifying patients who should be offered alternate treatment pathways. As a first step, clinicians need a screening tool to identify patients with Opioid Use Disorder (OUD) and to assess for OUD severity. Because such a tool is not available, the study team composed of eight chronic pain and/or addiction experts has extended a validated screening instrument to develop a brief and novel consensus screening tool to identify OUD and assess for OUD severity for treatment stratification. Our screening tool has the potential to assist busy outpatient clinicians to assess OUD among patients receiving long-term opioid therapy for chronic pain.

2.
Bioresour Technol ; 155: 334-41, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24463408

RESUMEN

Six species of marine and freshwater green macroalgae were cultivated in outdoor tanks and subsequently converted to biocrude through hydrothermal liquefaction (HTL) in a batch reactor. The influence of the biochemical composition of biomass on biocrude yield and composition was assessed. The freshwater macroalgae Oedogonium afforded the highest biocrude yield of all six species at 26.2%, dry weight (dw). Derbesia (19.7%dw) produced the highest biocrude yield for the marine species followed by Ulva (18.7%dw). In contrast to significantly different yields across species, the biocrudes elemental profiles were remarkably similar with higher heating values of 33-34MJkg(-1). Biocrude productivity was highest for marine Derbesia (2.4gm(-2)d(-1)) and Ulva (2.1gm(-2)d(-1)), and for freshwater Oedogonium (1.3gm(-2)d(-1)). These species were therefore identified as suitable feedstocks for scale-up and further HTL studies based on biocrude productivity, as a function of biomass productivity and the yield of biomass conversion to biocrude.


Asunto(s)
Biocombustibles , Chlorophyta/química , Calor , Biomasa , Carbono/análisis , Chlorophyta/crecimiento & desarrollo , Agua Dulce , Microbiología Industrial/instrumentación , Microbiología Industrial/métodos , Especificidad de la Especie
3.
Nanoscale ; 4(11): 3482-9, 2012 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-22552632

RESUMEN

The first continuous, real-time spectroscopic monitoring of a photo-driven cargo delivery event from a mesoporous silica-based nanocarrier inside a single living cell is reported. By chemically attaching azobenzene molecules inside the 3 nm pore channels of mesoporous silica nanoparticles (∼70 nm diameter), the escape of the cargo molecule [propidium iodide (PI)] from the pore is prevented in the dark but is facilitated by the light-driven isomerization motion. Real-time spectroscopic measurements of a single cell uncover intermediate processes that occur during this intracellular delivery event, from nanomachine activation to the release of PI into the cytosol and to PI's eventual intercalation with nuclear DNA. Changes in PI's fluorescence intensity and the hypsochromic shift of the band maxima are used to identify the local environment of the fluorophore that is being observed in the cell. The ability to precisely initiate a chemical event inside an individual cell and continuously monitor the subsequent biological responses will enhance our understanding of intracellular process upon drug, protein and nucleic acid delivery.


Asunto(s)
Nanopartículas/química , Compuestos Azo/química , Línea Celular , ADN/química , Humanos , Sustancias Intercalantes/química , Microscopía Fluorescente , Porosidad , Propidio/química , Dióxido de Silicio/química
5.
Nucleosides Nucleotides Nucleic Acids ; 29(4-6): 457-60, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20544537

RESUMEN

AMP deaminase could be a potential target for treatment of heart disease but experimental evaluation of this concept is difficult due to limited availability of inhibitors with proven efficiency in biological systems. This study evaluated the effect of 3-[2-(3-carboxy-4-bromo-5,6,7,8-tetrahydronaphthyl)ethyl]-3,6,7,8-tetrahydroimidazo [4,5-d][1,3]diazepin-8-ol, an AMP deaminase inhibitor (AMPDI) on the pathways of nucleotide metabolism in perfused rat heart. We show that AMPDI at 0.3 mM concentration effectively inhibits AMP deaminase in this experimental model.


Asunto(s)
AMP Desaminasa/antagonistas & inhibidores , Azepinas/farmacología , Inhibidores Enzimáticos/farmacología , Corazón/efectos de los fármacos , Imidazoles/farmacología , Animales , Miocardio/enzimología , Miocardio/metabolismo , Nucleótidos/metabolismo , Ratas
6.
Med Hypotheses ; 74(1): 39-44, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19717244

RESUMEN

The natural selection hypothesis suggests that lighter skin colour evolved to optimise vitamin D production. Some authors question if vitamin D deficiency leads to sufficient health problems to act as a selection pressure. This paper reviews the numerous effects of vitamin D deficiency on human health and argues that vitamin D deficiency is sufficient to pose as a potent selection pressure for lighter skin colour. Vitamin D deficiency manifesting as rickets and osteomalacia are sufficient to impair reproductive success, but additionally, animal studies and some clinical observations suggest that vitamin D may have more direct impact on human fertility. Vitamin D deficiency may lead to a whole host of clinical conditions which impair health and increase mortality rates: increase susceptibility to bacterial and viral infections; rickets, osteomalacia and osteoporosis, with increased risk of falls and fractures; increased risk of cancers; hypertension and cardiovascular disease; maturity onset diabetes; autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease and Type 1 diabetes; and gum disease. We submit that at higher latitudes, lighter skin colour evolved to facilitate vitamin D production under conditions of low ultra-violet B radiation in order to avoid a plethora of ill health, reproductive difficulties and early mortality.


Asunto(s)
Neoplasias/metabolismo , Deficiencia de Vitamina D/complicaciones , Deficiencia de Vitamina D/diagnóstico , Vitamina D/metabolismo , Adulto , Anciano , Niño , Preescolar , Ensayos Clínicos como Asunto , Femenino , Fertilidad , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Modelos Biológicos , Modelos Teóricos , Neoplasias/patología , Riesgo , Pigmentación de la Piel
7.
Ann Trop Paediatr ; 29(3): 239-42, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19689869

RESUMEN

Pseudomonas aeruginosa is a common infection in immunocompromised patients. However, it can also cause severe infections in otherwise healthy individuals. We describe pseudomonal bacteraemia in a 6-month-old boy with significant obstruction of the nasopharynx by pseudomonal debris, which we termed pseudomembranous nectrotising pharyngitis. To prevent aspiration and suffocation, early recognition and removal of the obstruction by endoscopy is recommended.


Asunto(s)
Bacteriemia/microbiología , Faringitis/diagnóstico , Faringitis/microbiología , Infecciones por Pseudomonas/microbiología , Úlcera/microbiología , Obstrucción de las Vías Aéreas/microbiología , Antibacterianos/uso terapéutico , Bacteriemia/tratamiento farmacológico , Preescolar , Fisura Anal/microbiología , Humanos , Masculino , Nasofaringe/microbiología , Úlceras Bucales/microbiología , Faringitis/tratamiento farmacológico , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/aislamiento & purificación
8.
Nanoscale ; 1(1): 16-39, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20644858

RESUMEN

Time and time again humanity is faced with a unifying global crisis that crosses the many great divides in different societies and serves to bring once segregated communities back together as a collective whole. This global community instinctively turns to science to develop the means of addressing its most pressing problems. More often than not, these forces dictate the direction that scientific research takes. This influence is no more apparent than in the field of supramolecular chemistry where, for decades now, its responsibility to tackle such issues has been put on the back burner as a consequence of a lack of platforms with which to deliver this contemporary brand of chemistry to meaningful applications. However, the tide is slowly turning as new materials emerge from the field of nanotechnology that are poised to host the many attractive attributes that are inherent in the chemistry of these supermolecules and also in the mechanostereochemistry of mechanically interlocked molecules (MIMs), which can be reused as a sequel to supramolecular chemistry. Mesoporous silica nanoparticles (SNPs) have proven to be supremely effective solid supports as their surfaces are easily functionalised with either supermolecules or MIMs. In turn, the blending of supramolecular chemistry and mechanostereochemistry with mesoporous SNPs has led to a new class of materials - namely, mechanised SNPs that are effectively biological nanoscale 'bombs' that have the potential to infiltrate cells and then, upon the pulling of a chemical trigger, explode! The development of these materials has been driven by the need to devise new therapies for the treatment of cancer. Recent progress in research promises not only to control the acuteness of this widespread and insidious disease, but also to make the harsh treatment less debilitating to patients. This global scourge is the unifying force that has brought together supramolecular chemistry, mechanostereochemistry and nanotechnology, uniting these three communities for the common good. At the nanoscale level, the mechanism for the release of cargos from the confines of the nanopores in the SNPs is accomplished by way of mechanical modifications made on the surface of these functionalised supports. These mechanical motions rely on both supramolecular, i.e., host-guest complexes, and mechanostereochemical phenomena (e.g., bistable rotaxanes), which are often stimulated by changes in pH, light and redox potentials, in addition to enzymatic catalysis. The future of this field lies in the development of 'smart bombs' wherein the loaded mechanised SNPs are endocytosed selectively by cancer cells, whereupon an intracellular trigger causes release of a cytotoxin, effectively leading to apoptosis. This review serves to highlight (1) the evolution of surface-functionalisation of SNPs with supermolecules and also with MIMs, (2) the mechanisms through which controlled-release of cargo from mechanised SNPs occurs, and (3) results from the in vitro application of these mechanised SNPs.


Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Nanopartículas , Nanotecnología , Modelos Moleculares , Dióxido de Silicio
9.
Nucleosides Nucleotides Nucleic Acids ; 27(6): 830-4, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18600548

RESUMEN

We recently discovered new nucleotides (4-pyridone-3-carboxamide-1-beta -D-ribonucleoside phosphates) in human erythrocytes. To establish the precursor compound and pathways of nucleotide derivative formation and breakdown, human erythrocytes were incubated for 3 hours with 0.3 mM 4-pyridone-3-carboxamide-1-beta-D-ribonucleoside (4PYR) and erythrocyte concentrations of 4PYR and adenine nucleotides were followed. 4PYR triphosphate increased from 16.1 +/- 0.6 micro M to 74.9 +/- 9.17 and 4PYR monophosphate increased from 5 micro M to 254.7 +/- 13.9 micro M. Conversely, incubation with 0.3 mM 4-pyridone-3-carboxamide (4PY) did not lead to additional 4PYR nucleotide formation. 4PYR nucleotides were catabolized to 4PYR. We conclude that 4PYR nucleotides are formed in erythrocytes by nucleoside kinase-mediated 4PYR phosphorylation and catabolized by 5'nucleotidase-mediated dephosphorylation.


Asunto(s)
Eritrocitos/metabolismo , Nucleósidos/sangre , Nucleósidos/metabolismo , Nucleótidos/sangre , Nucleótidos/metabolismo , Humanos , Incubadoras , Nucleósidos/química , Factores de Tiempo
10.
Nucleosides Nucleotides Nucleic Acids ; 27(6): 863-6, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18600553

RESUMEN

Following discovery of NAD(+)-dependent reactions that control gene expression, cytoprotection, and longevity, there has been a renewed therapeutic interest in precursors, such as nicotinamide and its derivatives. We tested 20 analogues of nicotinamide for their ability to protect endothelial cells from peroxynitrite stress and their effect on poly (ADP-ribose) polymerase (PARP) activity. Several nicotinamide derivatives protected endothelial cells from peroxynitrite-induced depletion of cellular NAD(+) and ATP concentrations, but only some of these compounds inhibited PARP. We conclude that some nicotinamide derivatives provide protection of endothelial cells against peroxynitrite-induced injury independent of inhibition of PARP activity. Preservation of the NAD(+) pool was a common effect of these compounds.


Asunto(s)
Citoprotección/efectos de los fármacos , Células Endoteliales/citología , Células Endoteliales/efectos de los fármacos , Niacinamida/análogos & derivados , Niacinamida/farmacología , Línea Celular , Células Endoteliales/metabolismo , Humanos , NAD/metabolismo , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Factores de Tiempo
11.
Nucleosides Nucleotides Nucleic Acids ; 27(6): 867-71, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18600554

RESUMEN

Because mutation of AMP deaminase 1 gene leading to reduced AMP deaminase activity may result in protection of cardiac function in patients with heart disease, inhibitors of AMP deaminase (AMPD) may have therapeutic applications. This study evaluated the effect of a specific inhibitor of AMP deaminase 3-[2-(3-carboxy-4-bromo-5,6,7,8-tetrahydronaphthyl)ethyl]-3,6,7,8-tetrahydroimidazo [4,5-d][1,3]diazepin-8-ol (AMPDI) on the isolated human enzyme and on nucleotide catabolism in rat cardiomyocytes. AMPDI effectively inhibited isolated human AMPD with an IC(50) = 0.5 micro M. AMPDI was much less effective with isolated cardiomyocytes (IC(50) = 0.5 mM). AMPDI is a very effective inhibitor of AMPD that despite lower efficiency in the cell system examined could be useful for in vivo studies.


Asunto(s)
AMP Desaminasa/antagonistas & inhibidores , Azepinas/farmacología , Inhibidores Enzimáticos/farmacología , Imidazoles/farmacología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/enzimología , Adenosina/metabolismo , Animales , Azepinas/síntesis química , Inhibidores Enzimáticos/síntesis química , Humanos , Imidazoles/síntesis química , Inosina Monofosfato/metabolismo , Miocitos Cardíacos/metabolismo , Ratas
12.
Cytogenet Genome Res ; 119(1-2): 15-20, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-18160776

RESUMEN

We report a newborn male with multiple congenital anomalies including growth retardation, hypotonia, dysmorphic facies, widely-spaced nipples, micropenis, cryptorchidism, optic nerve hypoplasia, heart disease, and a striking, high-pitched cry. Chromosome analysis revealed de novo partial trisomy 11q due to a der(5)t(5;11)(p15.3;q22). Fluorescence in situ hybridization (FISH) showed loss of the 5p telomere signal on the der(5) chromosome, indicating the infant has partial monosomy 5p in addition to partial trisomy 11q. Among cases involving trisomy 11q, an unusual cry has only been documented in the presence of a der(5)t(5p;11q). This apparent dependence of the abnormal cry on monosomy 5p suggested the same genetic mechanism that occurs in Cri du chat syndrome (CDCS) may be responsible for the atypical cry in der(5)t(5p;11q) individuals. Neither a commercial CDCS probe (LSI D5S23, D5S721) nor a series of BAC clones encompassing distal regions implicated in the CDCS-associated cat-cry were deleted in our patient. These results suggest a second cry-modifying locus maps telomeric to BAC RP11-94J21 in band 5p15.33. This locus may not only cause the abnormal cry in individuals with a der(5)t(5p;11q) but could also contribute to the phenotypic variability and discordant mapping studies observed for CDCS.


Asunto(s)
Anomalías Múltiples/genética , Deleción Cromosómica , Cromosomas Humanos Par 5/genética , Llanto , Hibridación Fluorescente in Situ , Anomalías Múltiples/patología , Humanos , Lactante , Cariotipificación , Masculino
13.
Artículo en Inglés | MEDLINE | ID: mdl-17761409

RESUMEN

The aim of this study was to determine whether supplementation with the n-3 long-chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid in patients with chronic refractory epilepsy is associated with beneficial changes in cerebral biochemistry. In a 3-month pilot randomized double-blind placebo-controlled study, three patients received eicosapentaenoic acid and docosahexaenoic acid daily and four received a placebo. 31-Phosphorus neurospectroscopy showed a decrease in phosphodiesters, an increase in gammaNTP and an increase in the broadband component in the active group over this period, while the opposite changes occurred in the placebo group. Therefore, in chronic refractory epilepsy, omega-3 supplementation may be associated with reduced membrane phospholipid breakdown in the brain, an improvement in brain energy metabolism, and an increased level of phospholipids in membranes and/or vesicle bilayers in cells in the brain. The unfavourable biochemical changes observed in the placebo group may be a feature of chronic intractable epilepsy.


Asunto(s)
Encéfalo/metabolismo , Ácidos Docosahexaenoicos , Ácido Eicosapentaenoico , Epilepsia/tratamiento farmacológico , Ácidos Grasos Omega-3 , Adulto , Anciano , Encéfalo/anatomía & histología , Ácidos Docosahexaenoicos/metabolismo , Ácidos Docosahexaenoicos/uso terapéutico , Ácido Eicosapentaenoico/metabolismo , Ácido Eicosapentaenoico/uso terapéutico , Ácidos Grasos Omega-3/metabolismo , Ácidos Grasos Omega-3/uso terapéutico , Humanos , Espectroscopía de Resonancia Magnética , Persona de Mediana Edad , Proyectos Piloto , Placebos
14.
Nucleosides Nucleotides Nucleic Acids ; 25(9-11): 1221-4, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17065095

RESUMEN

Xenotransplantation is one be possible solution for a severe shortage of human organs available for transplantation. However, only a few studies addressed metabolic compatibility of transplanted animal organs. Our aim was to compare activities of adenosine metabolizing enzymes in the heart of different species that are relevant to clinical or experimental xenotransplantation. We noted fundamental differences: ecto-5' nucleotidease (E5' N) activity was 4-fold lower in pig and baboon hearts compared to the human hearts while mouse activity was compatible with human and rat activity was three times higher than human. There also were significant differences in AMP-deaminase (AMPD), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities. We conclude that differences in nucleotide metabolism may contribute to organ dysfunction after xenotransplantation.


Asunto(s)
Trasplante de Corazón/métodos , Nucleótidos/química , Trasplante Heterólogo/métodos , 5'-Nucleotidasa/biosíntesis , AMP Desaminasa/biosíntesis , Adenosina/química , Adenosina Desaminasa/biosíntesis , Animales , Humanos , Ratones , Papio , Purina-Nucleósido Fosforilasa/biosíntesis , Ratas , Especificidad de la Especie , Porcinos
15.
Int J Cancer ; 119(7): 1567-76, 2006 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-16688717

RESUMEN

Nasopharyngeal carcinoma (NPC) is a common disease in Hong Kong and southern provinces of China. EBV infection is believed to play a critical role in the development of NPC. Previous studies on the transformation mechanism of EBV genes were mostly performed in either NPC or nonnasopharyngeal epithelial cells which may not be representative of premalignant nasopharyngeal epithelial cells. Establishment of a representative cell system would greatly facilitate the elucidation of the role of EBV infection in the development of NPC. Using telomerase alone, we were able to establish an immortalized nasopharyngeal epithelial cell line from primary nonmalignant nasopharyngeal biopsies. The telomerase-immortalized nasopharyngeal epithelial cells are largely diploid in karyotype. Interestingly, this newly immortalized nasopharyngeal epithelial cell line, referred as NP460hTert, harbors genetic alterations previously identified in premalignant and malignant nasopharyngeal epithelial cells. These include inactivation of p16 by homozygous deletion of the p16(INK4A) locus and downregulation of RASSF1A expression. The deletion of the p16(INK4A) locus appears to be the most crucial event for the immortalization of nasopharyngeal epithelial cells by telomerase and precedes RASSF1A downregulation. In addition, detailed analysis of the cytogenetic changes by conventional cytogenetics, spectral karyotyping (SKY) and array-based CGH revealed a gain of a 17q21-q25 fragment on 11p15 chromosome in all NP460hTert cells which occurred before deletion of the p16(INK4A) locus. Gain of 17q has been previously reported in NPC. In addition, activation of NF-kappaB was observed in immortalized NP460hTert cells at the later population doublings, and may play a role in the survival of immortalized NP epithelial cells. Id1 which is commonly expressed in various human cancers, including NPC, was also upregulated in the immortalized NP460hTert cells. Thus, the establishment of an immortalized nasopharyngeal epithelial cell line harboring common genetic alterations present in premalignant and cancerous nasopharyngeal epithelial cells may provide a valuable cell system to examine for early events involved in NPC carcinogenesis, particularly in elucidating the role of EBV infection in NPC development.


Asunto(s)
Células Epiteliales/citología , Células Epiteliales/metabolismo , Nasofaringe/citología , Nasofaringe/metabolismo , Telomerasa/metabolismo , Proliferación Celular , Forma de la Célula , Células Cultivadas , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Regulación de la Expresión Génica , Humanos , Cariotipificación , FN-kappa B/metabolismo , Telomerasa/genética
16.
J Neurol Neurosurg Psychiatry ; 77(1): 101-3, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16361605

RESUMEN

Levetiracetam (Lev) is a new antiepileptic drug with a distinct mechanism of action, shown in regulatory trials to be effective. These controlled trials do not always predict how useful a drug will be in day to day clinical practice. Retention rates can provide a better indication of efficacy and tolerability in everyday use. Patients attending a tertiary referral centre for epilepsy and who received Lev in the first 2 years of its marketing were assessed (n = 811) to determine continuation rates of treatment with this drug. At the last follow up, 65% of patients were still taking Lev, and the estimated 3 year retention rate was 58%. In total, 11% attained seizure freedom of at least 6 months. Patients taking greater numbers of concurrent antiepileptic drugs (AEDs) were more likely to discontinue Lev, and those reaching higher maximum daily dosages were less likely to discontinue Lev. The retention rate for Lev compares favourably with that of other new AEDs.


Asunto(s)
Anticonvulsivantes/metabolismo , Anticonvulsivantes/uso terapéutico , Epilepsia/tratamiento farmacológico , Piracetam/análogos & derivados , Adolescente , Adulto , Anciano , Anticonvulsivantes/efectos adversos , Estudios de Cohortes , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Levetiracetam , Masculino , Persona de Mediana Edad , Piracetam/efectos adversos , Piracetam/metabolismo , Piracetam/uso terapéutico , Factores de Tiempo
17.
J Hand Surg Br ; 31(1): 72-5, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16289720

RESUMEN

De Quervain's disease is a stenosing tenovaginitis involving the first extensor compartment of the wrist. The similarity of its symptomatology to a number of other conditions and its controversial aetiology are only a few of the barriers which often delay its diagnosis and treatment. We report the first two cases in the literature of abductor pollicus longus tendon rupture in patients with De Quervain's disease who had been treated with conservative methods. The relevant literature is reviewed.


Asunto(s)
Traumatismos de los Tendones , Tenosinovitis/complicaciones , Adulto , Anciano de 80 o más Años , Síndrome del Túnel Carpiano/complicaciones , Síndrome del Túnel Carpiano/cirugía , Femenino , Humanos , Rotura , Férulas (Fijadores) , Tendones/cirugía
18.
Artículo en Inglés | MEDLINE | ID: mdl-16021912

RESUMEN

We compared concentrations of nucleotide substrates and activities of enzymes of nucleotide metabolism in pig and human blood, heart, and kidney. The most important difference was lower ecto-5-nucleotidase (ESN) activity in both pig hearts and kidney. Furthermore, higher hypoxanthine, inosine, adenine, and uracil, but lower uridine and uric acid concentrations were observed in pig blood as compared to human. A twofold increase in UTP concentration has been observed in pig hearts following 4 h perfusion with human blood. Purine metabolism is an important target for genetic and pharmacological manipulation during xenotransplantations.


Asunto(s)
Purinas/metabolismo , Trasplante Heterólogo/métodos , 5'-Nucleotidasa/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Animales Modificados Genéticamente , Cromatografía Líquida de Alta Presión , Humanos , Riñón/metabolismo , Miocardio/metabolismo , Especificidad de la Especie , Porcinos , Uridina Trifosfato/metabolismo
19.
Artículo en Inglés | MEDLINE | ID: mdl-16021914

RESUMEN

Ecto-5'-nucleotidase (E5'N) is an extracellular enzyme forming anti-inflammatory and immunosuppressive adenosine. We evaluated whether confrontation of pig heart and endothelial cells with human blood changes the activity of E5'N. Pig hearts were perfused ex vivo with fresh human blood for 4 h. Pig aortic endothelial cells (PAEC) were incubated in vitro with human plasma for 3 h. Ex vivo perfusion of pig heart with fresh human blood resulted in a decrease in E5'N activity to 62% and 61% of initial in wild-type and transgenic pig hearts, respectively. PAEC activity of E5'N decreased to 71% and 50% of initial after 3 h exposure to heat-inactivated and active complement human plasma, respectively, while it remained constant in controls. Pig heart activity of E5'N decreased following exposure to human blood, which may affect adenosine production and exacerbate hyperacute and vascular rejection.


Asunto(s)
5'-Nucleotidasa/antagonistas & inhibidores , 5'-Nucleotidasa/metabolismo , Sangre/metabolismo , Endotelio Vascular/metabolismo , Animales , Animales Modificados Genéticamente , Aorta/metabolismo , Proteínas del Sistema Complemento , Endotelio Vascular/citología , Humanos , Nucleótidos/química , Perfusión , Transducción de Señal , Especificidad de la Especie , Porcinos , Factores de Tiempo , Trasplante Heterólogo
20.
Artículo en Inglés | MEDLINE | ID: mdl-16021913

RESUMEN

Adenosine (Ado) triggers several protective mechanisms that may attenuate development of heart failure, both locally and systemically. We developed a procedure allowing sustained increase in endogenous Ado production by the combined application of Ado metabolism inhibitors and nucleotide precursors. We found that our procedure attenuate the development of heart failure induced by adriamycin.


Asunto(s)
Adenosina/metabolismo , Antibióticos Antineoplásicos/efectos adversos , Doxorrubicina/efectos adversos , Insuficiencia Cardíaca/inducido químicamente , Animales , Cromatografía Líquida de Alta Presión , Doxorrubicina/farmacología , Ecocardiografía , Insuficiencia Cardíaca/prevención & control , Nucleótidos/química , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
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