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1.
BMC Musculoskelet Disord ; 24(1): 615, 2023 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-37501088

RESUMEN

BACKGROUND: The effectiveness of physiotherapy to reduce low back pain depends on patient adherence to treatment. Facilitators and barriers to patient adherence are multifactorial and include patient and therapist-related factors. This Delphi study aimed to identify an expert consensus on aspects facilitating the adherence of patients with back pain to physiotherapy. METHOD: International experts were invited to participate in a three-round standard Delphi survey. The survey contained 49 items (32 original and 17 suggested by experts) which were rated on 5-point Likert scales. The items were assigned to six domains. The consensus level was defined as 60%. RESULTS: Of 38 invited experts, 15 followed the invitation and completed all three rounds. A positive consensus was reached on 62% of the 49 proposed items to facilitate adherence. The highest consensus was achieved in the domains "Influence of biopsychosocial factors" (89%) and "Influence of cooperation between physiotherapists and patients" (79%). Additional important domains were the "Influence of competencies of physiotherapists" (71%) and "Interdisciplinary congruence" (78%). "Administration aspects" and the "Use of digital tools" did not reach expert consensus. CONCLUSIONS: Biopsychosocial factors, therapeutic skills, and patient-physiotherapist collaboration should be considered in physiotherapy practice to facilitate adherence in patients with LBP. Future studies should prospectively evaluate the effectiveness of individual or combined identified aspects for their influence on patient adherence in longitudinal study designs.


Asunto(s)
Dolor de la Región Lumbar , Humanos , Dolor de la Región Lumbar/diagnóstico , Dolor de la Región Lumbar/terapia , Dolor de la Región Lumbar/psicología , Técnica Delphi , Estudios Longitudinales , Modalidades de Fisioterapia , Encuestas y Cuestionarios
2.
J Gen Physiol ; 150(1): 111-125, 2018 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-29247050

RESUMEN

Malignant hyperthermia (MH) is a fatal hypermetabolic state that may occur during general anesthesia in susceptible individuals. It is often caused by mutations in the ryanodine receptor RyR1 that favor drug-induced release of Ca2+ from the sarcoplasmic reticulum. Here, knowing that membrane depolarization triggers Ca2+ release in normal muscle function, we study the cross-influence of membrane potential and anesthetic drugs on Ca2+ release. We used short single muscle fibers of knock-in mice heterozygous for the RyR1 mutation Y524S combined with microfluorimetry to measure intracellular Ca2+ signals. Halothane, a volatile anesthetic used in contracture testing for MH susceptibility, was equilibrated with the solution superfusing the cells by means of a vaporizer system. In the range 0.2 to 3%, the drug causes significantly larger elevations of free myoplasmic [Ca2+] in mutant (YS) compared with wild-type (WT) fibers. Action potential-induced Ca2+ signals exhibit a slowing of their time course of relaxation that can be attributed to a component of delayed Ca2+ release turnoff. In further experiments, we applied halothane to single fibers that were voltage-clamped using two intracellular microelectrodes and studied the effect of small (10-mV) deviations from the holding potential (-80 mV). Untreated WT fibers show essentially no changes in [Ca2+], whereas the Ca2+ level of YS fibers increases and decreases on depolarization and hyperpolarization, respectively. The drug causes a significant enhancement of this response. Depolarizing pulses reveal a substantial negative shift in the voltage dependence of activation of Ca2+ release. This behavior likely results from the allosteric coupling between RyR1 and its transverse tubular voltage sensor. We conclude that the binding of halothane to RyR1 alters the voltage dependence of Ca2+ release in MH-susceptible muscle fibers such that the resting membrane potential becomes a decisive factor for the efficiency of the drug to trigger Ca2+ release.


Asunto(s)
Potenciales de Acción , Anestésicos por Inhalación/farmacología , Calcio/metabolismo , Fiebre/metabolismo , Halotano/farmacología , Fibras Musculares Esqueléticas/metabolismo , Animales , Células Cultivadas , Fiebre/genética , Masculino , Ratones , Contracción Muscular , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/fisiología , Canal Liberador de Calcio Receptor de Rianodina/genética
3.
PLoS One ; 12(3): e0173803, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28346464

RESUMEN

The study aim was to investigate the effect of endogenous insulin release on lipolysis in subcutaneous adipose tissue after adrenergic stimulation in obese subjects diagnosed with type 2 diabetes (T2D). In 14 obese female T2D subjects, or 14 obese non-T2D controls, glycerol concentration was measured in response to the α1,2,ß-agonist norepinephrine, the α1-agonist norfenefrine and the ß2-agonist terbutaline (each 10-4 M), using the microdialysis technique. After 60 minutes of stimulation, an intravenous glucose load (0.5 g/kg lean body mass) was given. Local blood flow was monitored by means of the ethanol technique. Norepinephrine and norfenefrine induced a four and three fold rise in glycerol dialysate concentration (p<0.001, each), with a similar pattern in adipose tissue. Following agonist stimulation and glucose infusion, endogenous insulin release inhibited lipolysis in the presence of norepinephrine, which was more rapid and pronounced in healthy obese controls than in T2D subjects (p = 0.024 obese vs T2D subjects). Insulin-induced inhibition of lipolysis in the presence of norfenefrine was similar in all study participants. In the presence of terbutaline the lipolysis rate increased two fold until the effect of endogenous insulin (p<0.001). A similar insulin-induced decrease in lipolysis was observed for each of the norfenefrine groups and the terbutaline groups, respectively. Adipose tissue blood flow remained unchanged after the iv-glucose load. Both norepinephrine and norfenefrine diminished blood flow slightly, but insulin reversed this response (p<0.001 over the entire time). Terbutaline alone and terbutaline plus increased endogenous insulin augmented local blood flow (p<0.001 over the entire time). In conclusion, a difference in insulin-induced inhibition of lipolysis was observed in obese T2D subjects compared to obese healthy controls following modulation of sympathetic nervous system activity and is assumed to be due to ß1-adrenoceptor mediated stimulation by norepinephrine.


Asunto(s)
Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/fisiopatología , Obesidad/complicaciones , Obesidad/fisiopatología , Grasa Subcutánea/inervación , Sistema Nervioso Simpático/fisiopatología , Agonistas Adrenérgicos/administración & dosificación , Agonistas Adrenérgicos/farmacología , Adulto , Glucemia/análisis , Diabetes Mellitus Tipo 2/sangre , Femenino , Glucosa/administración & dosificación , Glicerol/sangre , Humanos , Insulina/sangre , Lipólisis/efectos de los fármacos , Persona de Mediana Edad , Norepinefrina/administración & dosificación , Norepinefrina/farmacología , Obesidad/sangre , Octopamina/administración & dosificación , Octopamina/análogos & derivados , Octopamina/farmacología , Grasa Subcutánea/irrigación sanguínea , Grasa Subcutánea/efectos de los fármacos , Grasa Subcutánea/fisiopatología , Sistema Nervioso Simpático/efectos de los fármacos , Adulto Joven
4.
Cell Cycle ; 13(10): 1560-70, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24626197

RESUMEN

Glioblastoma are the most frequent and malignant human brain tumors, having a very poor prognosis. The enhanced radio- and chemoresistance of glioblastoma and the glioblastoma stem cells might be the main reason why conventional therapies fail. The second messenger cyclic AMP (cAMP) controls cell proliferation, differentiation, and apoptosis. Downregulation of cAMP sensitizes tumor cells for anti-cancer treatment. Opioid receptor agonists triggering opioid receptors can activate inhibitory Gi proteins, which, in turn, block adenylyl cyclase activity reducing cAMP. In this study, we show that downregulation of cAMP by opioid receptor activation improves the effectiveness of anti-cancer drugs in treatment of glioblastoma. The µ-opioid receptor agonist D,L-methadone sensitizes glioblastoma as well as the untreatable glioblastoma stem cells for doxorubicin-induced apoptosis and activation of apoptosis pathways by reversing deficient caspase activation and deficient downregulation of XIAP and Bcl-xL, playing critical roles in glioblastomas' resistance. Blocking opioid receptors using the opioid receptor antagonist naloxone or increasing intracellular cAMP by 3-isobutyl-1-methylxanthine (IBMX) strongly reduced opioid receptor agonist-induced sensitization for doxorubicin. In addition, the opioid receptor agonist D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux, whereas doxorubicin increased opioid receptor expression in glioblastomas. Furthermore, opioid receptor activation using D,L-methadone inhibited tumor growth significantly in vivo. Our findings suggest that opioid receptor activation triggering downregulation of cAMP is a promising strategy to inhibit tumor growth and to improve the effectiveness of anti-cancer drugs in treatment of glioblastoma and in killing glioblastoma stem cells.


Asunto(s)
Antineoplásicos/farmacología , Neoplasias Encefálicas/patología , AMP Cíclico/metabolismo , Glioblastoma/patología , Receptores Opioides mu/genética , Animales , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo , Doxorrubicina/farmacología , Doxorrubicina/uso terapéutico , Sinergismo Farmacológico , Glioblastoma/tratamiento farmacológico , Glioblastoma/metabolismo , Humanos , Metadona/farmacología , Metadona/uso terapéutico , Ratones , Ratones Desnudos , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/patología , Receptores Opioides mu/agonistas , Receptores Opioides mu/metabolismo
5.
Oncotarget ; 4(5): 677-90, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23633472

RESUMEN

Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies.


Asunto(s)
Adenilil Ciclasas/metabolismo , Apoptosis , AMP Cíclico/metabolismo , Leucemia de Células B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Receptores Opioides/metabolismo , Inhibidores de Adenilato Ciclasa , Analgésicos Opioides/farmacología , Animales , Antibióticos Antineoplásicos/farmacología , Caspasas/metabolismo , Línea Celular Tumoral , Regulación hacia Abajo , Doxorrubicina/sangre , Doxorrubicina/farmacología , Resistencia a Antineoplásicos , Activación Enzimática/efectos de los fármacos , Humanos , Masculino , Metadona/sangre , Metadona/farmacología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Trasplante de Neoplasias , Receptores Opioides/biosíntesis , Transducción de Señal/efectos de los fármacos
6.
Am J Physiol Gastrointest Liver Physiol ; 297(6): G1163-71, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19779015

RESUMEN

Mechanisms leading to acute pancreatitis after a fat-enriched meal combined with excess alcohol are incompletely understood. We have studied the effects of alcohol and fat (VLDL) on pancreatic acinar cell (PAC) function, oxidative stress, and repair mechanisms by pancreatic stellate cells (PSC) leading to fibrogenesis. To do so, PAC (rat) were isolated and cultured up to 24 h. Ethanol and/or VLDL were added to PAC. We measured PAC function (amylase, lipase), injury (lactic dehydrogenase), apoptosis (TUNEL, Apo2.7, annexin V binding), oxidative stress, and lipid peroxidation (conjugated dienes, malondialdehyde, chemoluminescence); we also measured PSC proliferation (bromodeoxyuridine incorporation), matrix synthesis (immunofluorescence of collagens and fibronectin, fibronectin immunoassay), and fatty acids in PAC supernatants (gas chromatography). Within 6 h, cultured PAC degraded and hydrolyzed VLDL completely. VLDL alone (50 microg/ml) and in combination with alcohol (0.2, 0.5, and 1% vol/vol) induced PAC injury (LDL, amylase, and lipase release) within 2 h through generation of oxidative stress. Depending on the dose of VLDL and alcohol, apoptosis and/or necrosis were induced. Antioxidants (Trolox, Probucol) reduced the cytotoxic effect of alcohol and VLDL. Supernatants of alcohol/VLDL-treated PAC stimulated stellate cell proliferation and extracellular matrix synthesis. We concluded that, in the presence of lipoproteins, alcohol induces acinar cell injury. Our results provide a biochemical pathway for the clinical observation that a fat-enriched meal combined with excess alcohol consumption can induce acinar cell injury (acute pancreatitis) followed by repair mechanisms (proliferation and increased matrix synthesis in PSC).


Asunto(s)
Proliferación Celular/efectos de los fármacos , Etanol/toxicidad , Matriz Extracelular/metabolismo , Lipoproteínas VLDL/toxicidad , Páncreas Exocrino/efectos de los fármacos , Pancreatitis/etiología , Enfermedad Aguda , Amilasas/metabolismo , Animales , Apoptosis/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Fibrosis , L-Lactato Deshidrogenasa/metabolismo , Lipasa/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Lipoproteínas VLDL/metabolismo , Estrés Oxidativo/efectos de los fármacos , Páncreas Exocrino/metabolismo , Páncreas Exocrino/patología , Pancreatitis/metabolismo , Pancreatitis/patología , Ratas , Ratas Wistar , Factores de Tiempo
7.
ACS Nano ; 3(10): 2953-64, 2009 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-19739601

RESUMEN

We report on the electromechanical actuation and switching performance of nanoconstructs involving doubly clamped, individual multiwalled carbon nanotubes. Batch-fabricated, three-state switches with low ON-state voltages (6.7 V average) are demonstrated. A nanoassembly architecture that permits individual probing of one device at a time without crosstalk from other nanotubes, which are originally assembled in parallel, is presented. Experimental investigations into device performance metrics such as hysteresis, repeatability and failure modes are presented. Furthermore, current-driven shell etching is demonstrated as a tool to tune the nanomechanical clamping configuration, stiffness, and actuation voltage of fabricated devices. Computational models, which take into account the nonlinearities induced by stress-stiffening of 1-D nanowires at large deformations, are presented. Apart from providing accurate estimates of device performance, these models provide new insights into the extension of stable travel range in electrostatically actuated nanowire-based constructs as compared to their microscale counterparts.

8.
Cancer Res ; 68(15): 6059-64, 2008 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-18676827

RESUMEN

The therapeutic opioid drug methadone (d,l-methadone hydrochloride) is the most commonly used maintenance medication for outpatient treatment of opioid dependence. In our study, we found that methadone is also a potent inducer of cell death in leukemia cells and we clarified the unknown mechanism of methadone-induced cell killing in leukemia cells. Methadone inhibited proliferation in leukemia cells and induced cell death through apoptosis induction and activated apoptosis pathways through the activation of caspase-9 and caspase-3, down-regulation of Bcl-x(L) and X chromosome-linked inhibitor of apoptosis, and cleavage of poly(ADP-ribose) polymerase. In addition, methadone induced cell death not only in anticancer drug-sensitive and apoptosis-sensitive leukemia cells but also in doxorubicin-resistant, multidrug-resistant, and apoptosis-resistant leukemia cells, which anticancer drugs commonly used in conventional therapies of leukemias failed to kill. Depending on caspase activation, methadone overcomes doxorubicin resistance, multidrug resistance, and apoptosis resistance in leukemia cells through activation of mitochondria. In contrast to leukemia cells, nonleukemic peripheral blood lymphocytes survived after methadone treatment. These findings show that methadone kills leukemia cells and breaks chemoresistance and apoptosis resistance. Our results suggest that methadone is a promising therapeutic approach not only for patients with opioid dependence but also for patients with leukemias and provide the foundation for new strategies using methadone as an additional anticancer drug in leukemia therapy, especially when conventional therapies are less effective.


Asunto(s)
Apoptosis/efectos de los fármacos , Resistencia a Antineoplásicos , Leucemia Linfoide/patología , Leucemia Mieloide/patología , Metadona/farmacología , Trastornos Relacionados con Opioides/tratamiento farmacológico , Western Blotting , Doxorrubicina/farmacología , Células HL-60 , Humanos , Metadona/uso terapéutico
9.
Int J Legal Med ; 122(3): 245-9, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18180941

RESUMEN

Ethyl glucuronide, as a direct metabolite of ethanol degradation, has proven useful as a long-term marker in many forensic applications. The inability to determine ethyl glucuronide in dried blood left a missing link in many investigations. Here, we describe a new method based on mass spectrometry in a Pauli-type ion trap in order to determine this substance in dried blood samples.


Asunto(s)
Análisis Químico de la Sangre , Cromatografía Liquida/métodos , Glucuronatos/análisis , Espectrometría de Masas en Tándem/métodos , Consumo de Bebidas Alcohólicas , Biomarcadores/análisis , Femenino , Toxicología Forense , Humanos , Masculino
10.
Eur J Oral Sci ; 115(6): 510-6, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18028061

RESUMEN

The aim of this in vitro study was to determine the diffusion of 2-hydroxyethyl methacrylate (HEMA) released from different bonding systems (BS) through dentin. Occlusal cavities with a remaining dentin thickness (RDT) of 0.5 mm (n=90) and 0.25 mm (n=80), respectively, were prepared in dentin discs of non-carious human molars. Artificial pulp chambers were attached to the pulpal side of each dentin disc. Bonding systems were applied with (Clearfil SE Bond, OptiBond FL, OptiBond Solo Plus) or without (AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, OptiBond FL, OptiBond Solo Plus Self Etch, Xeno III) prior phosphoric acid etching. HEMA was detected by gas chromatography/mass spectrometry (n=10 per BS and RDT). The highest mean HEMA concentration was found in the 0.25 mm RDT group treated with OptiBond FL (13.3 microg) and the lowest mean HEMA concentration was detected in the 0.5 mm RDT group treated with AdheSE (0.5 microg). At 0.25 mm RDT the quantities of HEMA recovered in the artificial pulp chambers were significantly higher than at 0.5 mm RDT, except for Clearfil SE Bond. Etching with phosphoric acid increased the detected HEMA quantities compared with self-etch BS. In deep cavity preparations, etching with phosphoric acid should be avoided in favor of the use of self-etch BS.


Asunto(s)
Grabado Dental/métodos , Recubrimientos Dentinarios/uso terapéutico , Dentina/efectos de los fármacos , Metacrilatos/análisis , Recubrimiento Dental Adhesivo/métodos , Materiales Dentales/efectos adversos , Dentina/ultraestructura , Recubrimientos Dentinarios/química , Métodos Epidemiológicos , Humanos , Ácidos Fosfóricos/efectos adversos
11.
Forensic Sci Int ; 168(2-3): 133-7, 2007 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-16908109

RESUMEN

A sensitive and specific method for the determination of gamma-hydroxybutyric acid (GHB) in urine and serum is described. Prior to quantification by LC/MS in a Pauli-type ion trap, the molecule is converted by a fast and simple one-step procedure into its n-butyl ester derivative. Hexa-deutero GHB has been used as internal standard.


Asunto(s)
Patologia Forense/métodos , Hidroxibutiratos/sangre , Hidroxibutiratos/orina , Espectrometría de Masas/métodos , Patologia Forense/instrumentación , Humanos , Espectrometría de Masas/instrumentación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
12.
J Pharmacol Exp Ther ; 314(3): 1267-73, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15947037

RESUMEN

Adverse 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) effects are usually ascribed to neurotransmitter release in the central nervous system. Since clinical features such as fasciculations, muscle cramps, rapidly progressing hyperthermia, hyperkalemia, and rhabdomyolysis point to the skeletal muscle as additional target, we studied the effects of MDMA on native and cultured skeletal muscle. We addressed the question whether malignant hyperthermia (MH)-susceptible (MHS) muscle is predisposed to adverse MDMA reactions. Force measurements on muscle strips showed that 100 microM MDMA, a concentration close to that determined in some MDMA users, regularly enhanced the sensitivity of skeletal muscle to caffeine-induced contractures but did not cause contractures on its own. The left-shift of the dose-response curve induced by MDMA was greater in normal than in MHS muscle. Furthermore, MDMA did not release Ca(2+) from isolated sarcoplasmic reticulum vesicles. These findings do not support the view of an MH-triggering effect on muscle. However, MDMA induced Ca(2+) transients in myotubes and increased their acidification rate. Surprisingly, alpha-bungarotoxin, a specific antagonist of the nicotinic acetylcholine receptor (nAChR), abolished these MDMA effects. The nAChR agonistic action of MDMA was confirmed by patch-clamp measurements of ion currents on human embryonic kidney cells expressing nAChR. We conclude that the neuromuscular junction is a target of MDMA and that an activation of nAChR contributes to the muscle-related symptoms of MDMA users. The drug may be of particular risk in individuals with abundant extrajunctional nAChR such as in generalized denervation or muscle regeneration processes and may act on central nAChR.


Asunto(s)
Músculo Esquelético/efectos de los fármacos , N-Metil-3,4-metilenodioxianfetamina/efectos adversos , Receptores Nicotínicos/efectos de los fármacos , Animales , Calcio/metabolismo , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Hipertermia Maligna/metabolismo , Contracción Muscular/efectos de los fármacos , Fibras Musculares Esqueléticas/efectos de los fármacos , Ratas , Retículo Sarcoplasmático/efectos de los fármacos , Retículo Sarcoplasmático/metabolismo
13.
Obes Res ; 12(4): 612-20, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15090628

RESUMEN

OBJECTIVE: To investigate the involvement of alpha1-adrenoceptors in the sympathetic regulation of glucose uptake in human adipocytes. RESEARCH METHODS AND PROCEDURES: Twenty-four severely obese subjects participated in this study. The microdialysis technique was used to determine interstitial glucose concentration after stimulation of abdominal subcutaneous adipose tissue with the alpha1-agonist norfenefrine, the alpha1,2beta-agonist norepinephrine, and both agents in combination with the alpha1-antagonist urapidil. The effect of beta-adrenoceptor stimulation was assessed by orciprenaline. Changes in local blood flow were determined using the ethanol escape technique. RESULTS: Both norfenefrine and norepinephrine induced a concentration-dependent decrease of interstitial glucose concentration, with a greater decrease observed with norepinephrine. Preperfusion of adipose tissue with urapidil inhibited glucose decrease. The inhibition was overcome with high concentrations of norfenefrine and norepinephrine, respectively. Both adrenergic agents induced tachyphylaxia. Urapidil enhanced extracellular glucose level at high concentration. Blood flow decreased in the presence of norfenefrine and norepinephrine but increased in response to urapidil. The accelerated blood flow due to urapidil was counteracted by norepinephrine and norfenefrine. Orciprenaline decreased interstitial glucose concentration and increased nutritive blood flow. The observed changes in blood flow induced by adrenergic agents were not related to glucose uptake. DISCUSSION: The stimulatory effect of the sympathetic nerves on glucose uptake in subcutaneous adipose tissue appears to be mediated by the alpha1-adrenoceptor. Norepinephrine enhances glucose entry into adipocytes independently of insulin action. In obese subjects with insulin resistance, the alpha1-adrenergic receptor may provide an important alternative pathway for glucose uptake.


Asunto(s)
Adipocitos/metabolismo , Glucosa/metabolismo , Receptores Adrenérgicos alfa 1/fisiología , Sistema Nervioso Simpático/fisiología , Agonistas alfa-Adrenérgicos/farmacología , Antagonistas Adrenérgicos alfa/farmacología , Adulto , Femenino , Humanos , Resistencia a la Insulina , Cinética , Microdiálisis , Persona de Mediana Edad , Norepinefrina/farmacología , Octopamina/análogos & derivados , Octopamina/farmacología , Piperazinas/farmacología , Receptores Adrenérgicos alfa 1/efectos de los fármacos
14.
Alcohol Alcohol ; 38(4): 364-8, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12814906

RESUMEN

AIMS: Leptin is a cytokine-type peptide hormone, recently implicated as a putative state marker of alcohol use and in craving. Our goal was to evaluate the potential of leptin as a state and trait marker and to rule out the role of current alcohol intoxication on leptin levels. METHODS: Eighteen alcohol withdrawal patients (16 males, 2 females) whose blood contained 202 mg/dl (median) of ethanol at hospitalization, who had a median age of 43.5 years and had consumed 1075 g of ethanol (median) in the last 7 days were included in the study. Leptin was determined in samples at day 1 (when still intoxicated) and day 7 of withdrawal. Expected leptin levels were calculated with a formula. For comparison, 27 blood samples of 18 abstinent persons, matched for gender, age and body mass index were used. Furthermore, mean cell volume, gamma-glutamyl transferase (GGT), blood glucose, cholesterol, triglycerides and body composition (bioimpedance device) were determined. For statistical analysis, SPSS 11 was used. RESULTS: Expected leptin levels were 1.71 ng/ml (median), leptin measured at day 1 was 2.65 ng/ml (median) and 2.85 ng/ml on day 7 for the alcohol withdrawal patients and 2.2 ng/ml (median) for the abstainers. These concentrations were not significantly different. Significant correlations were found between leptin day 1 and expected leptin levels, percentage fat body mass, cigarettes smoked per day, GGT and blood alcohol concentration. CONCLUSIONS: Our preliminary data do not support the hypothesis of leptin as a state or trait marker and suggest only a minor influence of acute intoxication on leptin levels in alcohol detoxification patients.


Asunto(s)
Alcoholismo/sangre , Leptina/sangre , Síndrome de Abstinencia a Sustancias/sangre , Templanza , Adulto , Biomarcadores/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadísticas no Paramétricas , Templanza/estadística & datos numéricos
15.
Alcohol Clin Exp Res ; 27(3): 471-6, 2003 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-12658113

RESUMEN

BACKGROUND: Considerable lives and money could be saved if one could detect early stages of lapsing/relapsing behavior in addicted persons (e.g., in safety-sensitive workplaces) and could disclose harmful drinking in social drinkers. Due to the serious public health problem of alcohol use and abuse worldwide, markers of alcohol use have been sought. Both ethyl glucuronide (EtG) and phosphatidyl ethanol (PEth) appear to have high sensitivity and specificity and a time frame of detection that may elucidate alcohol use not detected by standard testing. Our aim was to assess their potential for detecting recent covert alcohol use under controlled conditions. METHODS: Thirty-five forensic psychiatric inpatients in a closed ward who had committed a substance-related offense ( section sign 64 StGB), were followed for 12 months. The complete time spectrum of possible alcohol consumption was covered by the complementary use of breath and urinary ethanol (hours), urinary EtG (days), %carbohydrate-deficient transferrin (CDT)/PEth (weeks), and gamma-glutamyltranspeptidase (GGT)/mean corpuscular volume (MCV) (weeks-months). RESULTS: Fourteen of the 146 urine samples examined were positive for EtG. In all EtG-positive cases, patients reported alcohol consumption of between 40 and 200 g of ethanol 12-60 hr prior to testing. Urinary and breath ethanol were positive in only one case. In the blood samples, PEth was not positive in any case and %CDT did not exceed the reference value. Isoelectric focusing showed no abnormal Tf subtypes. CONCLUSIONS: The findings emphasize the diagnostic and therapeutic usefulness, specificity, and sensitivity of EtG as a marker of recent alcohol use. Such a test is needed in numerous settings, including alcohol and drug treatment (to detect lapse/relapse), in safety-sensitive work settings where use is dangerous or in other settings where use may be inappropriate (e.g., such as driving, workplace, pregnancy, or monitoring physicians or other professionals who are in recovery and working), or for testing other groups (such as children or those with medical problems) where alcohol use would be unhealthy or unsafe. The health, social and socioeconomic benefits arising from the future use of these markers is hard to overestimate.


Asunto(s)
Alcoholismo/orina , Psiquiatría Forense , Glucuronatos/orina , Adulto , Alcoholismo/psicología , Biomarcadores/orina , Femenino , Psiquiatría Forense/estadística & datos numéricos , Glicerofosfolípidos/orina , Humanos , Masculino , Persona de Mediana Edad , Curva ROC , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Estadísticas no Paramétricas
16.
Forensic Sci Int ; 128(1-2): 59-65, 2002 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-12208024

RESUMEN

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50 degrees C) and the extracts were cleaned-up with aminopropyl SPE columns. LC-MS/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation (ESI) using a triple quadrupole mass spectrometer (Sciex API 365) with a turboionspray source and post-column addition of acetonitrile for enhanced sensitivity. The MS/MS transitions monitored were m/z 221 -->75 for EtG and 226 -->75 for D(5)-EtG as an internal standard. The method was selective and sensitive, with a detection limit of 51 pg/mg hair at a signal-to-noise ratio of 3:1. The mean recovery was 96%, with an intra- and inter-day precision of less than 11.7% at a concentration of 200 pg/mg. The linearity was assessed in the range of 25-2000 pg/mg hair, with a correlation coefficient of 0.997. The method was successfully applied to 97 human hair samples which were taken at autopsies from persons with known alcoholism or were obtained from alcoholics who were hospitalized for ethanol withdrawal, from social drinkers and from children having not consumed any alcohol. Although, approximately two-third of the alcoholics showed EtG concentrations in hair of higher than 51 pg/mg (up to >4000 pg/mg), in one-third the EtG concentration was below the detection limit. However, only in one of five hair samples of "social drinkers", the EtG concentration was above the detection limit (51 pg/mg). No EtG has been detected in the hair of children. These investigations demonstrate that heavy alcohol consumption may be but not necessarily has to be detectable by EtG analysis in hair.


Asunto(s)
Medicina Legal/métodos , Glucuronatos/análisis , Cabello/química , Adulto , Alcoholismo/metabolismo , Preescolar , Cromatografía Liquida/métodos , Femenino , Humanos , Masculino , Espectrometría de Masas/métodos , Persona de Mediana Edad
17.
Addict Biol ; 7(4): 427-34, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14578020

RESUMEN

Ethyl glucuronide (EtG) is a promising new biological state marker of recent alcohol consumption that detects alcohol use reliably over a definite time period. Other currently available markers lack acceptable sensitivity and specificity. Our aim is to elucidate under naturalistic conditions the time course of EtG excretion in urine following alcohol consumption and to show how this can be utilized for monitoring and prognosis in patients. There are no other existing data on this issue to date. One hundred and thirty-eight urine samples from 28 male alcohol withdrawal patients were drawn every 3-24 hours for up to 94 hours after hospitalization. Breath ethanol concentration (mean) at hospitalization was 900 mg/L. Patient age in years was 40.3 (mean). Determination of urine EtG was performed by gas chromatography/mass spectrometry (GC/MS) with deuterium-labelled EtG as an internal standard. The strongest correlations (p<0.01) were found between EtG determinations in the different patient when breath ethanol concentrations (BEC) were 0 and 48 hours after BEC=0 (r=0.747), EtG 24 and 48 hours after BEC=0 (r=0.872), and in the time frame of detection (hours) of EtG and EtG 48 hours after BEC=0 (r=0.762). No significant correlation was found (Mann-Whitney test) between EtG concentrations in urine at different time points between the groups of patients with (a) 1 or less-2, (b) 3-4 or more previous hospitalizations, (c) a history of seizures (yes/no) or (d) an age above or below the median (40.5). EtG excretion in urine is not random, but seems rather to follow a kinetic profile. Furthermore our preliminary data indicate, that there is no significant difference for EtG concentration in urine when correlated to group variables such as age, seizures and hospitalizations.


Asunto(s)
Alcoholismo/orina , Glucuronatos/orina , Adulto , Alcoholismo/rehabilitación , Pruebas Respiratorias/instrumentación , Etanol/efectos adversos , Femenino , Cromatografía de Gases y Espectrometría de Masas/instrumentación , Glucuronatos/análisis , Cabello/química , Hospitalización/estadística & datos numéricos , Humanos , Masculino , Pronóstico , Sensibilidad y Especificidad , Síndrome de Abstinencia a Sustancias/etiología , Síndrome de Abstinencia a Sustancias/orina
18.
Addict Biol ; 6(3): 205-212, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11900598

RESUMEN

Ethyl glucuronide (EtG) is a non-volatile, water-soluble metabolite of ethanol, with a high storage stability. It can be detected in body fluids, tissues, sweat and hair for an extended time period after the elimination of ethanol from the body. EtG closes the gap between short-term markers for alcohol consumption such as ethanol or methanol and long-term markers for alcohol misuse such as GGT, MCV and CDT. Due to its specific time-frame of detection and its high sensitivity and specificity, EtG is a promising marker for alcohol consumption and for relapse control that enables the therapist to intervene at an early stage of relapsing behaviour. The aim of this review is to give an overview of analytical techniques for the detection of EtG, its clinical use and remaining questions.

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