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1.
Mar Environ Res ; 197: 106428, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38492503

RESUMEN

The critically endangered endemic bivalve Pinna nobilis from the Mediterranean Sea suffered a sudden population decline after a mass mortality event in early autumn 2016. Conservation efforts aimed at preventing extinction included safeguarding resistant individuals and implementing a breeding plan to contribute to the repopulation of the species. This study utilized a model combining Lagrangian dispersion and connectivity analyses to pinpoint optimal restocking sites in the Western Mediterranean. Our approach allowed to identify locations capable of sustaining and generating larvae for broader repopulation in key areas of the Western Mediterranean Sea prior to the mass mortality event. Six important repopulation locations from Murcia, Valencia and Balearic Islands were selected for reintroduction efforts. The results obtained in this study show how the network could be self-sufficient and able to self-replenish itself of recruits. Overall, our work can be used to direct the reintroduction of resistant animals in the Western Mediterranean Sea.


Asunto(s)
Bivalvos , Humanos , Animales , Mar Mediterráneo , España
2.
Aust Vet J ; 99(1-2): 46-54, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33227826

RESUMEN

There are limited techniques available to assess the health of sea turtles as physical examination has little correlation to clinical findings, and blood reference intervals are broad and provide limited prognostic significance. Advances in the portability of ultrasound machines allow echocardiography to be increasingly used in the health assessments of wild animals. This study performed blood analysis and echocardiograms on 11 green sea turtles upon admission to a rehabilitation clinic and six animals before release. Significant differences were seen between groups, with admission animals having significantly smaller diameters of the cavum arteriosum at systole and diastole, smaller E-waves and an increased fractional shortening. Pre-release animals displayed significant increases in the maximum blood velocities of both the pulmonary artery and the left aorta. Significant negative correlations were seen between fractional shortening and uric acid and between the velocity time integral of the pulmonary artery and urea. The pulmonary artery velocity time integral was also significantly correlated to the E wave. Furthermore, there was asynchrony between the cavum arteriosum and the cavum pulmonale and the detection of a parasitic granuloma in the ventricular outflow tract of one animal. Overall, the results suggest that cardiac function in stranded green sea turtles is significantly impaired and that echocardiography has applications in the health assessments of green sea turtles.


Asunto(s)
Tortugas , Animales , Animales Salvajes , Ecocardiografía/veterinaria , Pruebas Hematológicas/veterinaria , Valores de Referencia
3.
Eur J Nutr ; 58(1): 335-344, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29274034

RESUMEN

BACKGROUND: Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise-induced immune dysfunction, but there is a lack of research with clinically relevant in vivo measures. AIM: To investigate the effects of COL supplementation on in vivo immunity following prolonged exercise using experimental contact hypersensitivity (CHS) with the novel antigen diphenylcyclopropenone (DPCP). METHODS: In a double-blind design, 31 men were randomly assigned to COL (20 g/day) or placebo (PLA) for 58 days. Participants ran for 2 h at 60% maximal aerobic capacity on day 28 and received a primary DPCP exposure (sensitisation) 20 min after. On day 56, participants received a low-dose-series DPCP challenge to elicit recall of in vivo immune-specific memory (quantified by skinfold thickness 24 and 48 h later). Analysis of the dose-response curves allowed determination of the minimum dose required to elicit a positive response (i.e., sensitivity). RESULTS: There was no difference in summed skinfold thickness responses between COL and PLA at 24 h (p = 0.124) and 48 h (p = 0.405). However, sensitivity of in vivo immune responsiveness was greater with COL at 24 h (p < 0.001) and 48 h (p = 0.023) with doses ~ twofold greater required to elicit a positive response in PLA. CONCLUSIONS: COL blunts the prolonged exercise-induced decrease in clinically relevant in vivo immune responsiveness to a novel antigen, which may be a mechanism for reduced illness reports observed in the previous studies. These findings also suggest that CHS sensitivity is highly relevant to host defence.


Asunto(s)
Calostro/inmunología , Suplementos Dietéticos , Ejercicio Físico , Tolerancia Inmunológica/efectos de los fármacos , Adolescente , Adulto , Animales , Bovinos , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Embarazo , Tiempo , Adulto Joven
4.
Biomed Res Int ; 2017: 5453606, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28349062

RESUMEN

Cardiovascular disease in patients with end-stage renal disease (ESRD) is driven by a different set of processes than in the general population. These processes lead to pathological changes in cardiac structure and function that include the development of left ventricular hypertrophy and left ventricular dilatation and the development of myocardial fibrosis. Reduction in left ventricular hypertrophy has been the established goal of many interventional trials in patients with chronic kidney disease, but a recent systematic review has questioned whether reduction of left ventricular hypertrophy improves cardiovascular mortality as previously thought. The development of novel imaging biomarkers that link to cardiovascular outcomes and that are specific to the disease processes in ESRD is therefore required. Postmortem studies of patients with ESRD on hemodialysis have shown that the extent of myocardial fibrosis is strongly linked to cardiovascular death and accurate imaging of myocardial fibrosis would be an attractive target as an imaging biomarker. In this article we will discuss the current imaging methods available to measure myocardial fibrosis in patients with ESRD, the reliability of the techniques, specific challenges and important limitations in patients with ESRD, and how to further develop the techniques we have so they are sufficiently robust for use in future clinical trials.


Asunto(s)
Cardiomiopatías/fisiopatología , Enfermedades Cardiovasculares/fisiopatología , Corazón/fisiopatología , Fallo Renal Crónico/fisiopatología , Cardiomiopatías/diagnóstico por imagen , Cardiomiopatías/etiología , Enfermedades Cardiovasculares/diagnóstico por imagen , Enfermedades Cardiovasculares/etiología , Diagnóstico , Fibrosis/diagnóstico por imagen , Fibrosis/fisiopatología , Corazón/diagnóstico por imagen , Humanos , Hipertrofia Ventricular Izquierda/fisiopatología , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/diagnóstico por imagen , Diálisis Renal
5.
Biomed Res Int ; 2017: 5765417, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28194419

RESUMEN

There is accumulating evidence that the intestinal barrier and the microbiota may play a role in the systemic inflammation present in HD patients. HD patients are subject to a number of unique factors, some related to the HD process and others simply to the uraemic milieu but with common characteristic that they can both alter the intestinal barrier and the microbiota. This review is intended to provide an overview of the current methods for measuring such changes in HD patients, the mechanisms behind these changes, and potential strategies that may mitigate these modifications. Lastly, intradialytic exercise is an increasingly employed intervention in HD patients; however the potential implications that this may have for the intestinal barrier are not known; therefore future research directions are also covered.


Asunto(s)
Microbioma Gastrointestinal , Intestinos/microbiología , Intestinos/fisiopatología , Diálisis Renal/métodos , Femenino , Humanos , Masculino , Diálisis Renal/efectos adversos
6.
BMC Nephrol ; 17(1): 69, 2016 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-27391774

RESUMEN

BACKGROUND: There is emerging evidence that exercise training could positively impact several of the cardiovascular risk factors associated with sudden cardiac death amongst patients on haemodialysis. The primary aim of this study is to evaluate the effect of an intradialytic exercise programme on left ventricular mass. METHOD AND DESIGN: Prospective, randomised cluster open-label blinded endpoint clinical trial in 130 patients with end stage renal disease on haemodialysis. Patients will be randomised 1:1 to either 1) minimum of 30 min continuous cycling thrice weekly during dialysis or 2) standard care. The primary outcome is change in left ventricular mass at 6 months, assessed by cardiac MRI (CMR). In order to detect a difference in LV mass of 15 g between groups at 80 % power, a sample size of 65 patients per group is required. Secondary outcome measures include abnormalities of cardiac rhythm, left ventricular volumes and ejection fraction, physical function measures, anthropometric measures, quality of life and markers of inflammation, with interim assessment for some measures at 3 months. DISCUSSION: This study will test the hypothesis that an intradialytic programme of exercise leads to a regression in left ventricular mass, an important non-traditional cardiovascular risk factor in end stage renal disease. For the first time this will be assessed using CMR. We will also evaluate the efficacy, feasibility and safety of an intradialytic exercise programme using a number of secondary end-points. We anticipate that a positive outcome will lead to both an increased patient uptake into established intradialytic programmes and the development of new programmes nationally and internationally. TRIAL REGISTRATION NUMBER: ISRCTN11299707 (registration date 5(th) March 2015).


Asunto(s)
Fenómenos Fisiológicos Cardiovasculares , Terapia por Ejercicio , Ejercicio Físico/fisiología , Hipertrofia Ventricular Izquierda/diagnóstico por imagen , Hipertrofia Ventricular Izquierda/terapia , Fallo Renal Crónico/terapia , Tamaño Corporal , Volumen Cardíaco , Muerte Súbita Cardíaca/prevención & control , Terapia por Ejercicio/efectos adversos , Humanos , Hipertrofia Ventricular Izquierda/fisiopatología , Inflamación/sangre , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/fisiopatología , Imagen por Resonancia Magnética , Calidad de Vida , Diálisis Renal , Proyectos de Investigación , Volumen Sistólico
7.
Aust Vet J ; 94(6): 203-207, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27169383

RESUMEN

BACKGROUND: The virus family Papillomaviridae has been documented in a wide range of animal species and can cause benign and malignant proliferative lesions. The presence of concurrent lingual papillomas and squamous cell carcinomas (SCC) in cetaceans has also been documented in both wild and captive populations, suggesting malignant transformation of benign papilloma to SCC may occur in this species. CASE REPORT: In 2008, a 38-year-old captive male inshore bottlenose dolphin (Tursiops aduncus) was diagnosed with papillomatous lesions on the intermandibular frenulum rostral to the tongue and an infiltrative SCC of the soft palate following biopsy and histological analysis. A treatment regimen of piroxicam and doxycycline was initiated with misoprostol as a gastroprotectant. The treatment resulted in a marked reduction in tumour size and reversible hepatotoxicosis. Subsequent biopsies revealed the presence of SCC in the oral cavity; however, the disease remains stable at the time of writing. CONCLUSION: To the best of our knowledge, this case is the first report of piroxicam and doxycycline used to treat SCC in a bottlenose dolphin. The treatment was successful in reducing the clinical presentation of the disease.

8.
Scand J Med Sci Sports ; 25(6): 788-96, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25727914

RESUMEN

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise-induced immune dysfunction. The aims of this study were to identify the effects of 4 weeks of COL supplementation on neutrophil responses and mucosal immunity following prolonged exercise. In a randomized double-blind, parallel group design, participants [age 28 ± 8 years; body mass 79 ± 7 kg; height 182 ± 6 cm; maximal oxygen uptake (V̇O2max) 55 ± 9 mL/kg/min] were assigned to 20 g per day of COL (n = 10) or an isoenergetic/isomacronutrient placebo (PLA; n = 10) for 4 weeks. Venous blood and unstimulated saliva samples were obtained before and after 2.5 h of cycling at 15% Δ (∼55-60% V̇O2max). A significantly greater formyl-methionyl-leucyl phenylalanine-stimulated oxidative burst was observed in the COL group compared with PLA group (P < 0.05) and a trend toward a time × group interaction (P = 0.06). However, there was no effect of COL on leukocyte trafficking, phorbol-12-myristate-13-acetate-stimulated oxidative burst, bacterial-stimulated neutrophil degranulation, salivary secretory IgA, lactoferrin or lysozyme (P > 0.05). These findings provide further evidence of the beneficial effects of COL on receptor-mediated stimulation of neutrophil oxidative burst in a model of exercise-induced immune dysfunction.


Asunto(s)
Calostro/inmunología , Suplementos Dietéticos , Ejercicio Físico/fisiología , Mucosa Bucal/inmunología , Neutrófilos/inmunología , Estallido Respiratorio , Adulto , Animales , Bovinos , Degranulación de la Célula , Método Doble Ciego , Humanos , Inmunoglobulina A/metabolismo , Recuento de Leucocitos , Mucosa Bucal/metabolismo , N-Formilmetionina Leucil-Fenilalanina/farmacología , Cultivo Primario de Células , Estallido Respiratorio/efectos de los fármacos , Saliva/inmunología , Saliva/metabolismo , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacología , Adulto Joven
11.
Chemosphere ; 68(9): 1650-9, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17524450

RESUMEN

Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs.


Asunto(s)
DDT/análisis , Hexaclorobenceno/análisis , Hexaclorociclohexano/análisis , Invertebrados/química , Bifenilos Policlorados/análisis , Contaminantes Químicos del Agua/análisis , Animales , Invertebrados/clasificación , Región Mediterránea , Factores de Tiempo , Contaminación Química del Agua
12.
J Alzheimers Dis ; 7(1): 25-35, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15750212

RESUMEN

Inflammation mediated by activated microglia cells has been shown to contribute to the pathogenesis of Alzheimer disease (AD) [1]. Microglia are the immune cells in the central nervous system, and when activated they secrete the lipid-derived mediator prostaglandin E2 (PGE2), the cytokine interleukin-1beta (IL-1beta), and other inflammatory mediators. Apolipoprotein E isoform 4 (apoE4), coded for by the gene APOE4 (epsilon4), has been shown to correlate with higher risk of onset of AD, as well as with increased severity of other diseases with a neuroinflammatory component. This study investigated isoform-specific effects of apoE on the regulation of PGE2, COX2, and IL-1beta expression. Two physiologically relevant preparations of apoE displayed an isoform-specific effect on inflammation in primary adult microglia cultured from adult rat brain cortex. Specifically, apoE4 alone, but not the more common isoform apoE3, stimulated secretion of PGE2 and IL-1beta. The increase in PGE2 release stimulated by apoE4 was not accompanied by the upregulation of the COX-2 enzyme in microglia.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/fisiopatología , Apolipoproteínas E/metabolismo , Dinoprostona/biosíntesis , Inflamación/metabolismo , Inflamación/fisiopatología , Interleucina-1/biosíntesis , Microglía/metabolismo , Prostaglandina-Endoperóxido Sintasas/biosíntesis , Isoformas de Proteínas/metabolismo , Animales , Ciclooxigenasa 2 , Ratas , Ratas Sprague-Dawley
13.
Neurobiol Aging ; 25(5): 675-83, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15172747

RESUMEN

Alzheimer disease (AD) involves glial inflammation associated with amyloid plaques. The role of the microglial cells in the AD brain is controversial, as it remains unclear if the microglia form the amyloid fibrils of plaques or react to them in a macrophage-phagocytic role. Also, it is not known why microglia are preferentially associated with some amyloid plaque types. This review will provide substantial evidence to support the phagocytic role of microglia in the brain as well as explain why microglia are generally associated with specific plaque types that may be explained through their unique mechanisms of formation. In summary, the data presented suggests that plaque associated microglial activation is typically subsequent to specific amyloid plaque formations in the AD brain.


Asunto(s)
Enfermedad de Alzheimer/patología , Encéfalo/patología , Microglía/patología , Fagocitosis/fisiología , Placa Amiloide/metabolismo , Enfermedad de Alzheimer/metabolismo , Animales , Encéfalo/ultraestructura , Humanos , Modelos Biológicos
14.
Am J Psychiatry ; 158(11): 1856-63, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11691692

RESUMEN

OBJECTIVE: Postpartum depressive disorders lead to maternal disability and disturbed mother-infant relationships, but information regarding the rates of major depressive disorder in minority women is noticeably lacking. The goal of this study was to determine whether the risk factors for and rate of postpartum major depressive disorder in a predominantly African American and Hispanic clinic population would be similar to those reported for Caucasian women. METHOD: Investigators systematically screened all women scheduled for their first postpartum visit on selected days at four publicly funded inner-city community maternal health clinics in Dallas County (N=802). A multistage screening process included the Edinburgh Postnatal Depression Scale, the Inventory of Depressive Symptomatology, and the Structured Clinical Interview for DSM-IV for a maximum of three assessments during the initial 3-5-week postpartum period. RESULTS: The estimated rate of major depressive disorder during the postpartum period among women in this setting was between 6.5% and 8.5%. Only 50% of the depressed women reported onset following birth. Bottle-feeding and not living with one's spouse or significant other were associated with depression at the first evaluation; persistent depressive symptoms were linked with the presence of other young children at home. Greater severity of depressive symptoms at first contact predicted major depressive disorder several weeks later. CONCLUSIONS: Rates of postpartum depression among Latina and African American postpartum women are similar to epidemiologic rates for Caucasian postpartum and nonpostpartum women. As previously shown for Caucasian women, major depressive disorder in many Latina and African American postpartum women begins before delivery, revealing the need to screen pregnant women for depression.


Asunto(s)
Depresión Posparto/epidemiología , Población Urbana/estadística & datos numéricos , Adulto , Depresión Posparto/diagnóstico , Depresión Posparto/psicología , Progresión de la Enfermedad , Etnicidad/estadística & datos numéricos , Femenino , Predicción , Humanos , Servicios de Salud Materna , Escalas de Valoración Psiquiátrica , Calidad de Vida , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios
15.
Chem Commun (Camb) ; (21): 2210-1, 2001 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-12240115

RESUMEN

The ketone (+/-)-5, which embodies the bicyclic core associated with the title tRNA synthetase inhibitors 1 and 2, has been prepared via a three-component coupling reaction involving 2-(hydroxymethyl)cyclopent-2-enone (15), methylamine (6) and propiolamide (10); straightforward elaboration of the readily derived acetates (-)-21 and (+)-21 has provided the biologically active analogues 23 and 24, respectively, of the title compounds.


Asunto(s)
Aminoacil-ARNt Sintetasas/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Indenos/química , Sulfonamidas/química , Inhibidores Enzimáticos/farmacología , Indenos/farmacología , Sulfonamidas/farmacología
16.
Bioorg Med Chem Lett ; 10(20): 2263-6, 2000 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-11055334

RESUMEN

SB-203207 and 10 analogues have been prepared, by elaboration of altemicidin, and evaluated as inhibitors of isoleucyl, leucyl and valyl tRNA synthetases (IRS, LRS, and VRS, respectively). Substituting the isoleucine residue of SB-203207 with leucine and valine increased the potency of inhibition of LRS and VRS, respectively. The leucine derivative showed low level antibacterial activity, while several of the compounds inhibited IRS from Staphylococcus aureus WCUH29 more strongly than rat liver IRS.


Asunto(s)
Antibacterianos/síntesis química , Inhibidores Enzimáticos/síntesis química , Indenos/química , Indenos/síntesis química , Isoleucina-ARNt Ligasa/antagonistas & inhibidores , Piridinas , Sulfonamidas/química , Sulfonamidas/síntesis química , Compuestos de Azufre , Valina-ARNt Ligasa/antagonistas & inhibidores , Alcaloides/química , Animales , Antibacterianos/química , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Diseño de Fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Indenos/farmacología , Cinética , Hígado/enzimología , Pruebas de Sensibilidad Microbiana , Ratas , Relación Estructura-Actividad , Sulfonamidas/farmacología
17.
J Med Chem ; 43(19): 3495-504, 2000 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-11000004

RESUMEN

Three new peptidomimetics (1-3) have been developed with highly stable and conformationally constrained macrocyclic components that replace tripeptide segments of protease substrates. Each compound inhibits both HIV-1 protease and viral replication (HIV-1, HIV-2) at nanomolar concentrations without cytotoxicity to uninfected cells below 10 microM. Their activities against HIV-1 protease (K(i) 1.7 nM (1), 0.6 nM (2), 0.3 nM (3)) are 1-2 orders of magnitude greater than their antiviral potencies against HIV-1-infected primary peripheral blood mononuclear cells (IC(50) 45 nM (1), 56 nM (2), 95 nM (3)) or HIV-1-infected MT2 cells (IC(50) 90 nM (1), 60 nM (2)), suggesting suboptimal cellular uptake. However their antiviral potencies are similar to those of indinavir and amprenavir under identical conditions. There were significant differences in their capacities to inhibit the replication of HIV-1 and HIV-2 in infected MT2 cells, 1 being ineffective against HIV-2 while 2 was equally effective against both virus types. Evidence is presented that 1 and 2 inhibit cleavage of the HIV-1 structural protein precursor Pr55(gag) to p24 in virions derived from chronically infected cells, consistent with inhibition of the viral protease in cells. Crystal structures refined to 1.75 A (1) and 1.85 A (2) for two of the macrocyclic inhibitors bound to HIV-1 protease establish structural mimicry of the tripeptides that the cycles were designed to imitate. Structural comparisons between protease-bound macrocyclic inhibitors, VX478 (amprenavir), and L-735,524 (indinavir) show that their common acyclic components share the same space in the active site of the enzyme and make identical interactions with enzyme residues. This substrate-mimicking minimalist approach to drug design could have benefits in the context of viral resistance, since mutations which induce inhibitor resistance may also be those which prevent substrate processing.


Asunto(s)
Fármacos Anti-VIH/síntesis química , Inhibidores de la Proteasa del VIH/síntesis química , Proteasa del VIH/metabolismo , Compuestos Heterocíclicos/síntesis química , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Línea Celular , Cristalografía por Rayos X , Inhibidores de la Proteasa del VIH/química , Inhibidores de la Proteasa del VIH/farmacología , VIH-1/efectos de los fármacos , VIH-2/efectos de los fármacos , Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/farmacología , Humanos , Técnicas In Vitro , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/virología , Modelos Moleculares , Imitación Molecular , Péptidos/química , Relación Estructura-Actividad , Replicación Viral
18.
J Med Chem ; 43(7): 1271-81, 2000 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-10753465

RESUMEN

Inhibitors of proteolytic enzymes (proteases) are emerging as prospective treatments for diseases such as AIDS and viral infections, cancers, inflammatory disorders, and Alzheimer's disease. Generic approaches to the design of protease inhibitors are limited by the unpredictability of interactions between, and structural changes to, inhibitor and protease during binding. A computer analysis of superimposed crystal structures for 266 small molecule inhibitors bound to 48 proteases (16 aspartic, 17 serine, 8 cysteine, and 7 metallo) provides the first conclusive proof that inhibitors, including substrate analogues, commonly bind in an extended beta-strand conformation at the active sites of all these proteases. Representative superimposed structures are shown for (a) multiple inhibitors bound to a protease of each class, (b) single inhibitors each bound to multiple proteases, and (c) conformationally constrained inhibitors bound to proteases. Thus inhibitor/substrate conformation, rather than sequence/composition alone, influences protease recognition, and this has profound implications for inhibitor design. This conclusion is supported by NMR, CD, and binding studies for HIV-1 protease inhibitors/substrates which, when preorganized in an extended conformation, have significantly higher protease affinity. Recognition is dependent upon conformational equilibria since helical and turn peptide conformations are not processed by proteases. Conformational selection explains the resistance of folded/structured regions of proteins to proteolytic degradation, the susceptibility of denatured proteins to processing, and the higher affinity of conformationally constrained 'extended' inhibitors/substrates for proteases. Other approaches to extended inhibitor conformations should similarly lead to high-affinity binding to a protease.


Asunto(s)
Endopeptidasas/química , Inhibidores de Proteasas/química , Secuencia de Aminoácidos , Sitios de Unión , Cromatografía Líquida de Alta Presión , Dicroismo Circular , Cristalografía por Rayos X , Diseño de Fármacos , Endopeptidasas/metabolismo , Proteasa del VIH/química , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Molecular , Unión Proteica , Estructura Secundaria de Proteína , Especificidad por Sustrato
19.
Biochemistry ; 38(25): 7978-88, 1999 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-10387041

RESUMEN

High-resolution crystal structures are described for seven macrocycles complexed with HIV-1 protease (HIVPR). The macrocycles possess two amides and an aromatic group within 15-17 membered rings designed to replace N- or C-terminal tripeptides from peptidic inhibitors of HIVPR. Appended to each macrocycle is a transition state isostere and either an acyclic peptide, nonpeptide, or another macrocycle. These cyclic analogues are potent inhibitors of HIVPR, and the crystal structures show them to be structural mimics of acyclic peptides, binding in the active site of HIVPR via the same interactions. Each macrocycle is restrained to adopt a beta-strand conformation which is preorganized for protease binding. An unusual feature of the binding of C-terminal macrocyclic inhibitors is the interaction between a positively charged secondary amine and a catalytic aspartate of HIVPR. A bicyclic inhibitor binds similarly through its secondary amine that lies between its component N-terminal and C-terminal macrocycles. In contrast, the corresponding tertiary amine of the N-terminal macrocycles does not interact with the catalytic aspartates. The amine-aspartate interaction induces a 1.5 A N-terminal translation of the inhibitors in the active site and is accompanied by weakened interactions with a water molecule that bridges the ligand to the enzyme, as well as static disorder in enzyme flap residues. This flexibility may facilitate peptide cleavage and product dissociation during catalysis. Proteases [Aba67,95]HIVPR and [Lys7,Ile33,Aba67,95]HIVPR used in this work were shown to have very similar crystal structures.


Asunto(s)
Inhibidores de la Proteasa del VIH/química , VIH-1/enzimología , Imitación Molecular , Péptidos Cíclicos/química , Aminobutiratos/química , Asparagina/química , Sitios de Unión , Simulación por Computador , Cristalografía por Rayos X , Inhibidores de la Proteasa del VIH/síntesis química , Isoleucina/química , Leucina/química , Lisina/química , Modelos Moleculares , Oligopéptidos/química , Péptidos Cíclicos/síntesis química , Fenilalanina/química , Conformación Proteica , Estereoisomerismo , Valina/química
20.
Acad Radiol ; 6(6): 333-8, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10376063

RESUMEN

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the accuracy of touch-preparation cytologic examination of breast core biopsy specimens in predicting benign or malignant core histologic results. MATERIALS AND METHODS: One hundred two core biopsies were performed on 88 women with stereotactic or ultrasonographic (US) guidance. Slides were prepared by smearing one core sample on each slide, spraying the slides with fixative, and staining them with the Papanicolaou technique. Slides were blindly reviewed by a cytopathologist. Cytologic results were categorized as positive for malignancy, not diagnostic for malignancy, or insufficient for diagnosis. Results were correlated with histologic results from all specimens obtained during the core biopsy. RESULTS: Imaging depicted the lesions sampled for biopsy as masses (n = 70), clustered calcifications (n = 29), focal asymmetries (n = 2), or architectural distortion (n = 1). Touch-preparation slides of 87 (85%) lesions contained sufficient material for diagnosis. Cytologic results correctly identified 12 of 16 (three of five intraductal and nine of 11 invasive) malignancies in 10 of 13 masses and two of three clusters of calcifications. Two false-positive results occurred, both with fibroadenomas. Overall, touch-preparation studies produced 69 true-negative and four false-negative results. Excluding slides with insufficient material, the sensitivity, specificity, and accuracy of touch-preparation results were 75%, 97%, and 93%, respectively. Including insufficient samples, accuracy was 79%. CONCLUSION: Although touch-preparation cytologic examination of breast core biopsy specimens is fairly accurate in prediction of benign or malignant core histologic results, its correlation with histologic results is not sufficient to justify routine use in immediate counseling and treatment planning.


Asunto(s)
Biopsia con Aguja/métodos , Neoplasias de la Mama/patología , Mama/patología , Adulto , Anciano , Anciano de 80 o más Años , Calcinosis/diagnóstico , Citodiagnóstico , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Técnicas Histológicas , Humanos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad
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