Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 150
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Psychol Med ; 47(9): 1678-1689, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28173893

RESUMEN

BACKGROUND: Subjective reports of insomnia and hypersomnia are common in bipolar disorder (BD). It is unclear to what extent these relate to underlying circadian rhythm disturbance (CRD). In this study we aimed to objectively assess sleep and circadian rhythm in a cohort of patients with BD compared to matched controls. METHOD: Forty-six patients with BD and 42 controls had comprehensive sleep/circadian rhythm assessment with respiratory sleep studies, prolonged accelerometry over 3 weeks, sleep questionnaires and diaries, melatonin levels, alongside mood, psychosocial functioning and quality of life (QoL) questionnaires. RESULTS: Twenty-three (50%) patients with BD had abnormal sleep, of whom 12 (52%) had CRD and 29% had obstructive sleep apnoea. Patients with abnormal sleep had lower 24-h melatonin secretion compared to controls and patients with normal sleep. Abnormal sleep/CRD in BD was associated with impaired functioning and worse QoL. CONCLUSIONS: BD is associated with high rates of abnormal sleep and CRD. The association between these disorders, mood and functioning, and the direction of causality, warrants further investigation.


Asunto(s)
Trastorno Bipolar , Ritmo Circadiano/fisiología , Melatonina/metabolismo , Trastornos del Sueño-Vigilia , Adulto , Trastorno Bipolar/epidemiología , Trastorno Bipolar/metabolismo , Trastorno Bipolar/fisiopatología , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/metabolismo , Apnea Obstructiva del Sueño/fisiopatología , Trastornos del Sueño del Ritmo Circadiano/epidemiología , Trastornos del Sueño del Ritmo Circadiano/metabolismo , Trastornos del Sueño del Ritmo Circadiano/fisiopatología , Trastornos del Sueño-Vigilia/epidemiología , Trastornos del Sueño-Vigilia/metabolismo , Trastornos del Sueño-Vigilia/fisiopatología , Adulto Joven
2.
Neurochem Res ; 40(2): 284-92, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25135598

RESUMEN

Patients with liver cirrhosis often exhibit sleep-wake abnormalities, which are, at least to some extent, circadian in origin. A relatively novel non-pharmacological approach to circadian disruption is appropriately timed bright light therapy. The aims of this pilot study were to investigate sleep-wake characteristics of a well-characterized population of inpatients with cirrhosis, and to evaluate the efficacy of bright light therapy in the hospital setting. Twelve consecutive inpatients with cirrhosis underwent complete sleep-wake assessment, to include qualitative and semi-quantitative (actigraphic) indices of night-time sleep quality, daytime sleepiness, diurnal preference, habitual sleep timing, quality of life, mood and circadian rhythmicity [i.e. urine collections for measurement of the melatonin metabolite 6-sulphatoxymelatonin (aMT6s)]. Patients showed extremely impaired night sleep quality (Pittsburg Sleep Quality Index global score: 16.3 ± 2.1) and daytime sleepiness was common (Epworth Sleepiness Scale: 8.3 ± 3.2). Five patients were randomly assigned to a single room in which lighting was controlled in relation to timing, spectral composition and intensity (lights on at 06:30 and off at 22:30, blue-enriched, more intense light in the morning, red-enriched, less intense light in the afternoon/evening); the others stayed in identical rooms with standard lighting. Sleep diaries revealed poor sleep quality, prolonged sleep latency (67 ± 138 min) and a reduced sleep efficiency (69 ± 21%). These features were confirmed by actigraphy (sleep efficiency: 71 ± 13%; fragmentation index: 55 ± 15%). Quality of life was globally impaired, and mood moderately depressed (Beck Depression Inventory: 19.4 ± 7.9). Seven patients underwent serial urine collections: no circadian aMT6s rhythm was detected in any of them, neither at baseline, nor during the course of hospitalization in either room (n = 4). In conclusion, sleep and circadian rhythms in hospitalized, decompensated patients with cirrhosis are extremely compromised. Treatment with bright light therapy did not show obvious, beneficial effects, most likely in relation to the severity of disturbance at baseline.


Asunto(s)
Ritmo Circadiano , Hospitalización , Pacientes Internos , Cirrosis Hepática/fisiopatología , Cirrosis Hepática/terapia , Fototerapia , Sueño , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad
3.
Nat Med ; 2(12): 1348-53, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8946834

RESUMEN

In nonobese diabetic (NOD) mice, beta-cell reactive T-helper type 1 (Th1) responses develop spontaneously and gradually spread, creating a cascade of responses that ultimately destroys the beta-cells. The diversity of the autoreactive T-cell repertoire creates a major obstacle to the development of therapeutics. We show that even in the presence of established Th1 responses, it is possible to induce autoantigen-specific anti-inflammatory Th2 responses. Immune deviation of T-cell responses to the beta-cell autoantigen glutamate decarboxylase (GAD65), induced an active form of self-tolerance that was associated with an inhibition of disease progression in prediabetic mice and prolonged survival of syngeneic islet grafts in diabetic NOD mice. Thus, modulation of autoantigen-specific Th1/Th2 balances may provide a minimally invasive means of downregulating established pathogenic autoimmune responses.


Asunto(s)
Autoantígenos/uso terapéutico , Diabetes Mellitus Tipo 1/prevención & control , Glutamato Descarboxilasa/uso terapéutico , Supervivencia de Injerto/efectos de los fármacos , Trasplante de Islotes Pancreáticos , Células Th2/inmunología , Traslado Adoptivo , Animales , Autoanticuerpos/sangre , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/cirugía , Progresión de la Enfermedad , Femenino , Interferón gamma/metabolismo , Interleucina-4/metabolismo , Interleucina-5/metabolismo , Activación de Linfocitos , Ratones , Ratones Endogámicos NOD , Pancreatina/inmunología , Autotolerancia , Bazo/inmunología , Células TH1/inmunología
5.
Bioorg Med Chem Lett ; 19(1): 62-6, 2009 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-19041240

RESUMEN

Insulin-like growth factor receptor (IGF-1R) is a growth factor receptor tyrosine kinase that acts as a critical mediator of cell proliferation and survival. Inhibitors of this receptor are believed to provide a new target in cancer therapy. We previously reported an isoquinolinedione series of IGF-1R inhibitors. Now we have identified a series of 3-cyanoquinoline compounds that are low nanomolar inhibitors of IGF-1R. The strategies, synthesis, and SAR behind the cyanoquinoline scaffold will be discussed.


Asunto(s)
Antineoplásicos/síntesis química , Nitrilos/síntesis química , Quinolinas/síntesis química , Receptor IGF Tipo 1/antagonistas & inhibidores , Humanos , Nitrilos/farmacología , Quinolinas/farmacología , Relación Estructura-Actividad
6.
Artículo en Inglés | MEDLINE | ID: mdl-31236522

RESUMEN

Successful pregnancy requires adaptation in maternal physiology. During intrauterine life the mother's circadian timing system supports successful birth and postnatal development. Maternal melatonin is important to transmit circadian timing and day length to the fetus. This study aims to describe the third trimester of pregnancy among day (n = 5) and night (n = 3) workers by assessing their melatonin levels in a natural environment. Additionally, we describe the worker's metabolic profiles and compare the health status of the newborns between groups of day and night working mothers. Our results indicate an occurrence of assisted delivery (cesarean and forceps) among night workers. Moreover, the newborns of night workers showed lower Apgar index and breastfeeding difficulty indicating a worse condition to deal with the immediate outside the womb environment. Additionally, there was lower night-time melatonin production among pregnant night workers compared to day workers. These findings may be related to light-induced suppression of melatonin that occurs during night work. We conclude that night work and consequent exposure to light at unconventional times might compromise the success of pregnancy and the health of the newborn. Further studies need to be carried out to monitor pregnancy and newborn health in pregnant night workers.

7.
J Steroid Biochem Mol Biol ; 189: 265-273, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30710742

RESUMEN

There is a lack of research into 25-hydroxyvitamin D (25(OH)D) status, light exposure and sleep patterns in South Asian populations. In addition, results of research studies are conflicting as to whether there is an association between 25(OH)D status and sleep quality. We investigated 25(OH)D status, self-reported and actigraphic sleep quality in n = 35 UK dwelling postmenopausal women (n = 13 South Asians, n = 22 Caucasians), who kept daily sleep diaries and wore wrist-worn actiwatch (AWL-L) devices for 14 days. A subset of n = 27 women (n = 11 South Asian and n = 16 Caucasian) also wore a neck-worn AWL-L device to measure their light exposure. For 25(OH)D concentration, South Asians had a median ± IQR of 43.8 ± 28.2 nmol/L, which was significantly lower than Caucasians (68.7 ± 37.4 nmol/L)(P = 0.001). Similarly, there was a higher sleep fragmentation in the South Asians (mean ± SD 36.9 ± 8.9) compared with the Caucasians (24.7 ± 7.1)(P = 0.002). Non-parametric circadian rhythm analysis of rest/activity patterns showed a higher night-time activity (L5) (22.6 ± 14.0 vs. 10.5 ± 4.4; P = 0.0008) and lower relative amplitude (0.85 ± 0.07 vs. 0.94 ± 0.02; P < 0.0001) in the South Asian compared with the Caucasian women. More South Asians (50%) met the criteria for sleep disorders (PSQI score >5) than did Caucasians (27%) (P = 0.001, Fishers Exact Test). However, there was no association between 25(OH)D concentration and any sleep parameter measured (P > 0.05) in either ethnic group. South Asians spent significantly less time in illuminance levels over 200 lx (P = 0.009) than did Caucasians. Overall, our results show that postmenopausal South Asian women have lower 25(OH)D concentration than Caucasian women. They also have higher sleep fragmentation, as well as a lower light exposure across the day. This may have detrimental implications for their general health and further research into sleep quality and light exposure in the South Asian ethnic group is warranted.


Asunto(s)
Posmenopausia , Sueño , Deficiencia de Vitamina D/sangre , Vitamina D/análogos & derivados , Anciano , Asia Sudoriental/epidemiología , Pueblo Asiatico , Ritmo Circadiano , Femenino , Humanos , Persona de Mediana Edad , Posmenopausia/sangre , Trastornos del Sueño-Vigilia/sangre , Trastornos del Sueño-Vigilia/epidemiología , Reino Unido/epidemiología , Vitamina D/sangre , Deficiencia de Vitamina D/epidemiología , Población Blanca
8.
Bioorg Med Chem ; 16(20): 9202-11, 2008 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-18815050

RESUMEN

A series of substituted 7-alkenyl 4[3-chloro-4-(1-methyl-1H-imidazol-2-ylsulfanyl)]anilino-3-quinolinecarbonitrile analogs were synthesized and evaluated as MEK1 kinase inhibitors. The synthetic details, structure-activity relationships, biological activity, and selected oral exposure studies of these analogs are described. From these studies, compound 5m was chosen as a strong candidate for further evaluation. The selectivity of 5m was ascertained against a panel of 17 kinases, where activity was observed against EGFR, Src, Lyn, and IR kinases. Western blot studies in WM-266 cells demonstrated that 5m inhibited phosphorylation of ERK, while additional kinase pathways tested showed no inhibition at up to 10 microM of 5 m. PK studies, as well as a xenograft and in vivo biomarker studies are described for 5m.


Asunto(s)
Alquenos/química , Compuestos de Anilina/química , MAP Quinasa Quinasa 1/antagonistas & inhibidores , Nitrilos/síntesis química , Nitrilos/farmacología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Animales , Línea Celular Tumoral , Activación Enzimática/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Isoquinolinas/química , MAP Quinasa Quinasa 1/metabolismo , Ratones , Ratones Desnudos , Estructura Molecular , Neoplasias/enzimología , Nitrilos/química , Inhibidores de Proteínas Quinasas/química , Relación Estructura-Actividad , Especificidad por Sustrato , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Mol Cell Biol ; 14(4): 2731-9, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8139572

RESUMEN

The intrinsic stimulatory potential or potency of a eukaryotic gene activator is controlled by the interaction between the activation domain and the transcriptional machinery. To further understand this interaction, we undertook a biochemical study to identify parameters that could be used to modulate activator potency. We considered how varying the number of activation domains, their flexibility, and the number of promoter sites affects potency in a yeast nuclear extract. The effects of GAL4 derivatives bearing either one, two, or four herpes simplex virus VP16 activation domains (amino acids 413 to 454) were measured on DNA templates containing one or two GAL4 sites in a Saccharomyces cerevisiae nuclear extract. We found that multimerized VP16 activation domains acted synergistically to increase the potency of the activators. The spacing between the activation domains was critical, such that the increased flexibility imparted by a protein linker contributed to increased activator potency. With highly potent activators, the levels of transcription stimulated on a single site were saturating, whereas the stimulatory effect of weaker activators increased with the number of sites. We discuss how these biochemical studies relate to the mechanism of gene activation and synergy in a yeast in vitro system.


Asunto(s)
Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Proteína Vmw65 de Virus del Herpes Simple/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Transcripción Genética , Núcleo Celular/metabolismo , ADN de Hongos/metabolismo , Proteínas de Unión al ADN , Proteínas Fúngicas/aislamiento & purificación , Proteína Vmw65 de Virus del Herpes Simple/aislamiento & purificación , Modelos Biológicos , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/aislamiento & purificación , Proteínas Recombinantes de Fusión/metabolismo , Mapeo Restrictivo , Saccharomyces cerevisiae/metabolismo , Simplexvirus/metabolismo , Moldes Genéticos , Factores de Transcripción/metabolismo , Activación Transcripcional
10.
Sci Rep ; 7(1): 6967, 2017 07 31.
Artículo en Inglés | MEDLINE | ID: mdl-28761043

RESUMEN

PER3 gene polymorphisms have been associated with differences in human sleep-wake phenotypes, and sensitivity to light. The aims of this study were to assess: i) the frequency of allelic variants at two PER3 polymorphic sites (rs57875989 length polymorphism: PER3 4, PER3 5; rs228697 SNP: PER3 C, PER3 G) in relation to sleep-wake timing; ii) the effect of morning light on behavioural/circadian variables in PER3 4 /PER3 4 and PER3 5 /PER3 5 homozygotes. 786 Caucasian subjects living in Northern Italy donated buccal DNA and completed diurnal preference, sleep quality/timing and sleepiness/mood questionnaires. 19 PER3 4 /PER3 4 and 11 PER3 5 /PER3 5 homozygotes underwent morning light administration, whilst monitoring sleep-wake patterns and the urinary 6-sulphatoxymelatonin (aMT6s) rhythm. No significant relationship was observed between the length polymorphism and diurnal preference. By contrast, a significant association was observed between the PER3 G variant and morningness (OR = 2.10), and between the PER3 G-PER3 4 haplotype and morningness (OR = 2.19), for which a mechanistic hypothesis is suggested. No significant differences were observed in sleep timing/aMT6s rhythms between PER3 5 /PER3 5 and PER3 4 /PER3 4 subjects at baseline. After light administration, PER3 4 /PER3 4 subjects advanced their aMT6s acrophase (p < 0.05), and showed a trend of advanced sleep-wake timing. In conclusion, significant associations were observed between PER3 polymorphic variants/their combinations and both diurnal preference and the response to light.


Asunto(s)
Afecto , Ritmo Circadiano , Proteínas Circadianas Period/genética , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Femenino , Frecuencia de los Genes , Humanos , Italia , Masculino , Melatonina/análogos & derivados , Melatonina/orina , Persona de Mediana Edad , Fotofobia/genética , Sueño , Encuestas y Cuestionarios , Adulto Joven
11.
Poult Sci ; 85(1): 117-22, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16493954

RESUMEN

Growing pullets were maintained on 14-h photoperiods and given diets supplemented with 25 mg of melatonin (MEL)/kg during the final 7 h of the photo-period to investigate the role of MEL in sexual development. Melatonin diets were fed to 70 d (to mimic a transfer from 7 to 14 h at 70 d), from 105 d onward (to mimic a transfer from 14 to 7 h at 105 d), or throughout the trial (to mimic constant 7-h photoperiods). Control birds, which were fed normal diets, were maintained on 7 or 14 h, transferred from 7 to 14 h at 70 d, or transferred from 14 to 7 h at 105 d. The MEL groups matured 6 to 11 d later than the constant 14-h controls. The group mimicking a transfer from 7 to 14 h matured 35 d later than photostimulated controls, the group mimicking a 14 to 7-h change at 105 d matured 41 d earlier than birds given a decrease in day length; the third group matured 13 d earlier than constant 7-h controls. Although these data suggest that the birds did not perceive the final 7 h of the photoperiod as being part of the night, when given MEL diets, residual plasma MEL during the first 7 h of the photoperiod was atypically high, possibly preventing an interpretation of day and night. However, continuously high plasma MEL did not result in birds responding as if in constant darkness, because birds transferred from darkness to 14 h at 70 d would not have matured at a similar time to birds changed from 14 h to darkness at 105 d. Plasma LH concentrations for birds mimicking a 7 to 14 h change at 70 d were not significantly different from constant 7-h controls after the transfer to normal diets. The later maturity of the experimental groups, compared with constant 14-h controls, clearly indicated that MEL had some influence over hypothalamic activity and gonadal development.


Asunto(s)
Pollos/crecimiento & desarrollo , Melatonina/farmacología , Maduración Sexual/efectos de los fármacos , Animales , Esquema de Medicación , Femenino , Melatonina/sangre , Oviposición/efectos de los fármacos , Fotoperiodo
12.
Yearb Med Inform ; Suppl 1: S103-16, 2016 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-27488402

RESUMEN

OBJECTIVE: The objective of this review is to summarize the state of the art of clinical decision support (CDS) circa 1990, review progress in the 25 year interval from that time, and provide a vision of what CDS might look like 25 years hence, or circa 2040. METHOD: Informal review of the medical literature with iterative review and discussion among the authors to arrive at six axes (data, knowledge, inference, architecture and technology, implementation and integration, and users) to frame the review and discussion of selected barriers and facilitators to the effective use of CDS. RESULT: In each of the six axes, significant progress has been made. Key advances in structuring and encoding standardized data with an increased availability of data, development of knowledge bases for CDS, and improvement of capabilities to share knowledge artifacts, explosion of methods analyzing and inferring from clinical data, evolution of information technologies and architectures to facilitate the broad application of CDS, improvement of methods to implement CDS and integrate CDS into the clinical workflow, and increasing sophistication of the end-user, all have played a role in improving the effective use of CDS in healthcare delivery. CONCLUSION: CDS has evolved dramatically over the past 25 years and will likely evolve just as dramatically or more so over the next 25 years. Increasingly, the clinical encounter between a clinician and a patient will be supported by a wide variety of cognitive aides to support diagnosis, treatment, care-coordination, surveillance and prevention, and health maintenance or wellness.


Asunto(s)
Sistemas de Apoyo a Decisiones Clínicas/tendencias , Sistemas de Apoyo a Decisiones Clínicas/historia , Predicción , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Informática Médica/historia , Informática Médica/tendencias
13.
Biochim Biophys Acta ; 1302(1): 84-92, 1996 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-8695659

RESUMEN

Pre-incubation of cultured human skin fibroblasts, lung fibroblasts and vascular smooth muscle cells, for 24 h with cAMP-elevating agents resulted in a significant increase (40-60%) of the cells' capacity to bind HDL. The increase was due to enhancement of the maximal binding capacity of a high affinity saturable site which binds HDL in preference to LDL. The effect was dependent upon the concentration of the cAMP-elevating agents and required more than 4 h to become evident. Cyclic AMP-mediated elevation of HDL binding occurred in cells with access to an exogenous source of cholesterol, which could be the physiological donor LDL or non-lipoprotein in origin. The observed effects were not subsequent to changes in cellular balance of cholesterol to cholesterol ester and were not due to inhibition of cellular proliferation.


Asunto(s)
AMP Cíclico/metabolismo , Fibroblastos/metabolismo , Lipoproteínas HDL/metabolismo , Piel/metabolismo , Células Cultivadas , Colesterol/metabolismo , Colesterol/farmacología , Ésteres del Colesterol/metabolismo , Colforsina/farmacología , AMP Cíclico/farmacología , Humanos , Pulmón/metabolismo , Músculo Liso Vascular/metabolismo
14.
Biochim Biophys Acta ; 1391(2): 117-32, 1998 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-9554975

RESUMEN

Elevation of cAMP concurrently enhances cholesterol efflux and binding of HDL3 in human skin fibroblasts. These effects were observed regardless of the route by which cAMP levels were increased. Cholesterol efflux and HDL3 binding were stimulated by the cAMP analogue CPT-cAMP, the adenylate cyclase activator forskolin, and by iloprost and prostaglandin E1 (PGE1) (which elevate cAMP via receptor-mediated processes). Dideoxyforskolin and PGF2alpha, which do not elevate cAMP, altered neither cholesterol efflux nor binding of HDL3. Inhibition of protein kinase A with H89 abolished the stimulatory effects of CPT-cAMP and iloprost, suggesting protein kinase A involvement in enhancing cholesterol efflux and HDL3 binding. Enhancement of HDL3 binding by iloprost was due to increased maximal capacity of the cells to bind HDL3, i.e., a greater number of HDL3 binding sites. A positive correlation was demonstrated between changes in HDL3 binding and changes in [3H]cholesterol efflux. The data are compatible with a model in which cholesterol efflux is partially dependent upon HDL binding to the cells. A short exposure to iloprost was sufficient to stimulate cAMP synthesis, triggering a chain of events leading to increased HDL3 binding and [3H]cholesterol efflux 20-24 h later. We conclude that both cholesterol efflux and the maximal capacity for HDL3 binding are enhanced by elevation of cellular cAMP. Cyclic AMP-elevating prostanoids could initiate these responses in vivo.


Asunto(s)
Alprostadil/farmacología , Colesterol/metabolismo , AMP Cíclico/biosíntesis , Iloprost/farmacología , Lipoproteínas HDL/metabolismo , Sitios de Unión , Transporte Biológico Activo/efectos de los fármacos , Células Cultivadas , Colforsina/farmacología , Dinoprost/farmacología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Humanos , Cinética , Lipoproteínas HDL3
15.
Biochim Biophys Acta ; 713(2): 270-9, 1982 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-7150615

RESUMEN

L-3-Hydroxyacyl-CoA dehydrogenase was measured in mammalian tissues with long-chain (C16) and short-chain (C4) 3-ketoacyl-CoA substrates. The majority of the activity was mitochondrial. Activity with C16 substrate was enriched in the inner membrane fraction while the matrix showed enrichment of activity with C4 substrate. Gel-filtration in the presence of nonionic and ionic detergents separated two peaks of activity with C16 substrate from liver, heart, kidney and brown adipose tissue mitochondria. The highest molecular weight activity was associated with membrane fragments and accounted for 18-32% of the total activity with C16 substrate. This enzyme showed preference for long-chain substrate, the C16/C4 activity ratio being 6-15 for the different mitochondria studied. The other enzyme had a molecular weight of 71 000 and showed highest activity with C4 substrate (C16/C4 activity ratio of 0.2). The substrate specificity of the membrane-associated enzyme was not altered by extraction with detergent or lipid solvents. The membrane-associated enzyme could be partially purified by treatment with high concentrations of KCl and EDTA, when it showed a molecular weight of 186 000 while retaining its high C16/C4 activity ratio. Protease treatment caused loss of C4 activity from the high-molecular-weight enzyme without affecting its C16 activity. We conclude that an inner membrane-associated, long-chain-specific 3-ketoacyl-CoA dehydrogenase coexists in mitochondria with the better-documented matrix enzyme which shows preference for shorter-chain-length substrates.


Asunto(s)
3-Hidroxiacil-CoA Deshidrogenasas/metabolismo , Membranas Intracelulares/enzimología , Mitocondrias Cardíacas/enzimología , Mitocondrias Hepáticas/enzimología , Mitocondrias/enzimología , Tejido Adiposo Pardo/enzimología , Animales , Animales Recién Nacidos , Encéfalo/enzimología , Riñón/enzimología , Cinética , Masculino , Conejos , Ratas , Ratas Endogámicas , Especificidad por Sustrato , Distribución Tisular
16.
Biochim Biophys Acta ; 1429(1): 230-8, 1998 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-9920399

RESUMEN

Isolated human mitochondrial trifunctional protein was incubated with 2-hexadecenoyl-CoA, CoA and NAD+ and the resultant CoA esters measured. Steady state with respect to the concentrations of the intermediates 3-hydroxyhexadecanoyl-CoA and 3-ketohexadecanoyl-CoA and the rate of formation of the product tetradecanoyl-CoA was reached within 4 min. Flux was greatly enhanced by the addition of Tween 20 (0.2% v/v) which stimulated 3-ketoacyl-CoA thiolase activity by over 7-fold. When 3-ketoacyl-CoA thiolase was not stimulated, 3-hydroxyhexadecanoyl-CoA was the prominent CoA ester accumulated, presumably due to inhibition of 3-hydroxyacyl-CoA dehydrogenase activity by accumulated 3-ketoacyl-CoA, analogous to the inhibition of short-chain 3-hydroxyacyl-CoA dehydrogenase by 3-ketoacyl-CoA. When [NAD+]/[NADH] was varied at a fixed total [NAD++NADH], the overall flux was only inhibited by [NAD+]/[NADH] less than 1. In contrast, when [acetyl-CoA]/[CoA] was varied at a fixed total [CoA], much greater sensitivity was observed.


Asunto(s)
Acetilcoenzima A/metabolismo , Complejos Multienzimáticos/metabolismo , NAD/metabolismo , Acetilcoenzima A/farmacología , Acilcoenzima A/farmacología , Ésteres/análisis , Humanos , Concentración de Iones de Hidrógeno , Proteína Trifuncional Mitocondrial , NAD/farmacología , Polisorbatos/farmacología
17.
Biochim Biophys Acta ; 1454(1): 115-25, 1999 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-10354521

RESUMEN

The effects of aspirin metabolites on beta-oxidation were studied in skin fibroblasts from eight typical Reye's syndrome (RS) patients and controls. RS patients' cells did not differ from controls in rates of palmitate oxidation or in the three component activities of the mitochondrial trifunctional enzyme (MTE), indicating no inherited beta-oxidation defect. Aspirin metabolites salicylate, hydroxyhippurate and gentisate, but not aspirin, directly inhibited palmitate oxidation in control and RS cells. RS cells were significantly more sensitive to inhibition than controls at 0.5 to 5 mM salicylate. Inhibition was concentration-dependent and reversible. Inhibition did not occur in fibroblasts lacking activity of the long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) activity of MTE. Salicylate was therefore inhibiting beta-oxidation at this step. Hydroxyhippurate and salicylate reversibly inhibited HAD activities in extracts of control and RS cells. Studies with pure short-chain HAD and LCHAD (MTE) showed hydroxyhippurate and salicylate were competitive inhibitors of the former but mixed (not competitive) inhibitors of the latter. Both compounds inhibited the combined, three-step, MTE reaction measured in the physiological direction. We conclude that (1) salicylate and hydroxyhippurate decrease beta-oxidation in intact cells by reversible inhibition of LCHAD activity of the MTE, and (2) beta-oxidation in RS cells is inherently more sensitive to inhibition by low concentrations of salicylate than controls.


Asunto(s)
3-Hidroxiacil-CoA Deshidrogenasas/antagonistas & inhibidores , Antioxidantes/farmacología , Aspirina/farmacología , Complejos Multienzimáticos/antagonistas & inhibidores , Síndrome de Reye/metabolismo , Piel/efectos de los fármacos , 3-Hidroxiacil-CoA Deshidrogenasas/deficiencia , Aspirina/metabolismo , Catálisis , Niño , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Humanos , Proteína Trifuncional Mitocondrial , Oxidación-Reducción/efectos de los fármacos , Palmitatos/metabolismo , Piel/enzimología , Relación Estructura-Actividad , Tritio
18.
J Biol Rhythms ; 12(5): 467-77, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9376645

RESUMEN

In humans, the pineal hormone melatonin can phase shift a number of circadian rhythms (e.g., "fatigue", endogenous melatonin, core body temperature) together with the timing of prolactin secretion. It is uncertain, however, whether melatonin can fully entrain all human circadian rhythms. In this study, the authors investigated the effects of daily melatonin administration on sighted individuals kept in continuous very dim light. A total of 10 normal, healthy males were maintained in two separate groups in partial temporal isolation under constant dim light (< 8 lux) with attenuated sound and ambient temperature variations but with knowledge of clock time for two periods of 30 days. In these circumstances, the majority of individuals free run with a mean period of 24.3 h. In a double-blind, randomized crossover design, subjects received 5 mg melatonin at 20:00 h on Days 1 to 15 (Melatonin 1st) followed by placebo on Days 16 to 30 (Placebo 2nd) or vice versa (Placebo 1st, Melatonin 2nd) during Leg 1 with treatment reversed in Leg 2. The variables measured were melatonin (as 6-sulphatoxymelatonin), rectal temperature, activity, and sleep (actigraphy and logs). In the experiment, 9 of the 10 subjects free ran with Placebo 1st, whereas Melatonin 1st stabilized the sleep-wake cycle to 24 h in 8 of 10 individuals. In addition, 2 individuals showed irregular sleep with this treatment. In some subjects, there was a shortening of the period of the temperature rhythm without synchronization. Melatonin 2nd induced phase advances (5 of 9 subjects), phase delays (2 of 9 subjects), and stabilization (2 of 9 subjects) of the sleep-wake cycle with subsequent synchronization to 24 h in the majority of individuals (7 of 9). Temperature continued to free run in 4 subjects. Maximum phase advances in core temperature were seen when the first melatonin treatment was given approximately 2 h after the temperature acrophase. These results indicate that melatonin was able to phase shift sleep and core temperature but was unable to synchronize core temperature consistently. In the majority of subjects, the sleep-wake cycle could be synchronized.


Asunto(s)
Ritmo Circadiano/efectos de los fármacos , Melatonina/farmacología , Adulto , Temperatura Corporal/fisiología , Estudios Cruzados , Método Doble Ciego , Humanos , Iluminación , Melatonina/análogos & derivados , Melatonina/sangre , Melatonina/orina , Actividad Motora/fisiología , Sueño/fisiología , Vigilia/fisiología
19.
J Biol Rhythms ; 12(6): 604-17, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9406036

RESUMEN

Melatonin has chronobiotic properties in humans. It is able to phase shift strongly endogenous rhythms, such as core temperature and its own endogenous rhythm, together with the sleep-wake cycle. Its ability to synchronize free-running rhythms has not been fully investigated in humans. There is evidence for synchronization of the sleep-wake cycle, but the available data suggest that it is less effective with regard to endogenous melatonin and core temperature rhythms. When suitably timed, most studies indicate that fast release preparations are able to hasten adaptation to phase shift in both field and simulation studies of jet lag and shift work. Both subjective and objective measures support this statement. However, not all studies have been successful. Careful evaluation of the effects on work-related performance is required. When used to alleviate the non-24-h sleep-wake disorder in blind subjects, again most studies report a successful outcome using behavioral measures, albeit in a small number of individuals. The present data suggest, however, that although sleep-wake can be stabilized to 24 h, entrainment of other rhythms is exceptionally rare.


Asunto(s)
Ceguera/fisiopatología , Ritmo Circadiano/efectos de los fármacos , Melatonina/farmacología , Viaje , Tolerancia al Trabajo Programado/fisiología , Animales , Humanos
20.
Chronobiol Int ; 32(5): 701-10, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25839208

RESUMEN

Since there is less movement during sleep than during wake, the recording of body movements by actigraphy has been used to indirectly evaluate the sleep-wake cycle. In general, most actigraphic devices are placed on the wrist and their measures are based on acceleration detection. Here, we propose an alternative way of measuring actigraphy at the level of the arm for joint evaluation of activity and body position. This method analyzes the tilt of three axes, scoring activity as the cumulative change of degrees per minute with respect to the previous sampling, and measuring arm tilt for the body position inference. In this study, subjects (N = 13) went about their daily routine for 7 days, kept daily sleep logs, wore three ambulatory monitoring devices and collected sequential saliva samples during evenings for the measurement of dim light melatonin onset (DLMO). These devices measured motor activity (arm activity, AA) and body position (P) using the tilt sensing of the arm, with acceleration (wrist acceleration, WA) and skin temperature at wrist level (WT). Cosinor, Fourier and non-parametric rhythmic analyses were performed for the different variables, and the results were compared by the ANOVA test. Linear correlations were also performed between actimetry methods (AA and WA) and WT. The AA and WA suitability for circadian phase prediction and for evaluating the sleep-wake cycle was assessed by comparison with the DLMO and sleep logs, respectively. All correlations between rhythmic parameters obtained from AA and WA were highly significant. Only parameters related to activity levels, such as mesor, RA (relative amplitude), VL5 and VM10 (value for the 5 and 10 consecutive hours of minimum and maximum activity, respectively) showed significant differences between AA and WA records. However, when a correlation analysis was performed on the phase markers acrophase, mid-time for the 10 consecutive hours of highest (M10) and mid-time for the five consecutive hours of lowest activity (L5) with DLMO, all of them showed a significant correlation for AA (R = 0.607, p = 0.028; R = 0.582, p = 0.037; R = 0.620, p = 0.031, respectively), while for WA, only acrophase did (R = 0.621, p = 0.031). Regarding sleep detection, WA showed higher specificity than AA (0.95 ± 0.01 versus 0.86 ± 0.02), while the agreement rate and sensitivity were higher for AA (0.76 ± 0.02 versus 0.66 ± 0.02 and 0.71 ± 0.03 versus 0.53 ± 0.03, respectively). Cohen's kappa coefficient also presented the highest values for AA (0.49 ± 0.04) and AP (0.64 ± 0.04), followed by WT (0.45 ± 0.06) and WA (0.37 ± 0.04). The findings demonstrate that this alternative actigraphy method (AA), based on tilt sensing of the arm, can be used to reliably evaluate the activity and sleep-wake rhythm, since it presents a higher agreement rate and sensitivity for detecting sleep, at the same time allows the detection of body position and improves circadian phase assessment compared to the classical actigraphic method based on wrist acceleration.


Asunto(s)
Actigrafía , Ritmo Circadiano/fisiología , Monitoreo Ambulatorio/métodos , Postura/fisiología , Sueño/fisiología , Actigrafía/métodos , Adulto , Femenino , Humanos , Luz , Masculino , Melatonina/análisis , Melatonina/metabolismo , Temperatura Cutánea/fisiología , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA