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1.
Mindfulness (N Y) ; 10(4): 724-736, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30931014

RESUMEN

The development and evaluation of mindfulness-based interventions for a variety of psychological and medical disorders has grown exponentially over the past 20 years. Yet, calls for increasing the rigor of mindfulness research and recognition of the difficulties of conducting research on the topic of mindfulness have also increased. One of the major difficulties is the measurement of mindfulness, with varying definitions across studies and ambiguity with respect to the meaning of mindfulness. There is also concern about the reproducibility of findings given few attempts at replication. The current secondary analysis addressed the issue of reproducibility and robustness of the construct of self-reported mindfulness across two separate randomized clinical trials of mindfulness-based relapse prevention (MBRP), as an aftercare treatment for substance use disorder. Specifically, we tested the robustness of our previously published findings, which identified a latent construct of mindfulness as a significant mediator of the effect of MBRP on reducing craving following treatment. First, we attempted to replicate the findings in a separate randomized clinical trial of MBRP. Second, we conducted sensitivity analyses to test the assumption of the no-omitted confounder bias in a mediation model. The effect of MBRP on self-reported mindfulness and overall mediation effect failed to replicate in a new sample. The effect of self-reported mindfulness in predicting craving following treatment did replicate and was robust to the no-omitted confounder bias. The results of this work shine a light on the difficulties in the measurement of mindfulness and the importance of examining the robustness of findings.

3.
J Anim Sci ; 88(9): 3121-7, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20495121

RESUMEN

The objective was to determine the effects of natural- or synthetic-source vitamin E on reproductive efficiency in Angus-cross beef cows. In Exp. 1, one hundred fifty-two cows were fed hay and corn silage based diet and assigned to 1 of 3 dietary supplements (3 pens/treatment): 1) containing no additional vitamin E (CON), 2) formulated to provide 1,000 IU x d(-1) of synthetic-source vitamin E (SYN; all-rac or dl-alpha-tocopherol acetate), or 3) formulated to provide 1,000 IU x d(-1) of natural-source vitamin E (NAT; RRR or D-alpha-tocopherol acetate). In Exp. 2, seventy-five cows (2 reps/treatment) were assigned to similar treatments as Exp. 1; however, a vitamin-mineral supplement was offered for ad libitum intake and vitamin intake was calculated from predicted mineral intakes. Cows grazed pastures rather than being fed hay and corn silage as in Exp. 1. In Exp. 1 and 2, supplementation began 6 wk prepartum and continued until initiation of the breeding season. Blood samples were collected at calving (Exp. 1) or breeding (Exp. 2) to determine alpha-tocopherol concentration and weekly beginning 4 wk postpartum (Exp. 1) or 7 and 14 d before estrus synchronization (Exp. 2) to determine return to estrus via progesterone concentration. Cows were synchronized and bred by AI based on heat detection; nonresponding cows were time bred (AI) 66 h after PGF(2 alpha) injection, and cows returning to estrus after AI were bred by natural service. In Exp. 1, cows supplemented with NAT and SYN had greater (P < 0.001) serum concentrations of alpha-tocopherol at calving compared with CON cows. Dietary supplement did not affect (P >or= 0.55) the percentage of cows cycling before synchronization or the number of days to return to estrus by cows that resumed estrus before synchronization. Cows supplemented with SYN tended to have greater first service conception rates compared with CON and NAT (P = 0.09); however, first plus second services combined and overall conception rates were not affected (P >or= 0.23). In Exp. 2, NAT cows had greater (P = 0.002) concentrations of alpha-tocopherol at breeding, whereas there was no difference (P > 0.05) between SYN and CON. Supplementation of SYN or NAT did not affect (P >or= 0.17) days to resumption of estrus before breeding, first service, first plus second services combined, or overall conception rates. These data suggest that supplementation of SYN or NAT source vitamin E increased alpha-tocopherol concentration in cows; however, effects on reproductive efficiency are minimal.


Asunto(s)
Bovinos/fisiología , Reproducción/efectos de los fármacos , alfa-Tocoferol/química , alfa-Tocoferol/farmacología , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Embarazo , alfa-Tocoferol/administración & dosificación
4.
J Anim Sci ; 88(9): 3128-35, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20495133

RESUMEN

The objective of this study was to determine the effects of maternally supplemented natural- or synthetic-source vitamin E on suckling calf performance and immune response. In a 2-yr study, one hundred fifty-two 2- and 3-yr-old, spring-calving, Angus-cross beef cows were blocked by age, BW, and BCS into 1 of 3 isocaloric, corn-based dietary supplements containing 1) no additional vitamin E (CON), 2) 1,000 IU/d of synthetic-source vitamin E (SYN), or 3) 1,000 IU/d of natural-source vitamin E (NAT). Maternal supplementation began approximately 6 wk prepartum and continued until the breeding season. Colostrum from cows and blood from calves was collected 24 h postpartum for analysis of IgG concentration as an indicator of passive transfer and circulating alpha-tocopherol concentration. At 19 d of age, blood was collected from calves to determine the expression of CD14 and CD18 molecules on leukocytes. At 21 and 35 d of age, humoral immune response was measured by a subcutaneous injection, in the neck, with ovalbumin (20 mg; OVA) and blood samples collected weekly until d 63 of age to determine antibodies produced against OVA. At d 63 of age, calves were administered an intradermal injection of OVA (1 mg) in the neck to assess cell-mediated immunity, which was determined on d 65 of age by measuring nodule size with calipers. Circulating alpha-tocopherol concentrations were increased at both 24 h (P = 0.001) and at the day of initial OVA challenge (P < 0.001) in SYN and NAT compared with CON calves. No differences were detected (P > 0.05) for calf birth BW, ADG, or weaning BW. There were no differences (P > 0.05) in calf serum total IgG or cow colostrum total IgG at 24 h or presence of CD14 and CD18 receptors at d 19 of age. The NAT calves had a greater antigen response to OVA at d 63 than SYN calves (P = 0.01; treatment x day interaction). As an indicator of cell-mediated immunity to OVA, nodule size at 65 d of age was not affected (P = 0.92) by maternal dietary supplementation. In conclusion, calves suckling cows supplemented with natural- and synthetic-source vitamin E had increased circulating concentrations of alpha-tocopherol at 24 h, which appeared to continue throughout maternal supplementation; however, calf immune function and performance were not affected.


Asunto(s)
Bovinos/fisiología , Fenómenos Fisiologicos Nutricionales Maternos/efectos de los fármacos , Reproducción/efectos de los fármacos , alfa-Tocoferol/química , alfa-Tocoferol/farmacología , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Animales Lactantes , Bovinos/crecimiento & desarrollo , Bovinos/inmunología , Calostro/química , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Inmunoglobulina G/análisis , Embarazo , Aumento de Peso , alfa-Tocoferol/administración & dosificación
5.
J Chem Ecol ; 27(3): 547-68, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11441445

RESUMEN

Protease inhibitors (PIs) are plant compounds that can inhibit proteases of mammal, insect, or pathogen origin and are frequently induced by mechanical wounding, insect feeding, or pathogen infection. Nicotiana attenuata is a species that induces nicotine, volatiles, and phenolics in response to damage. Here we examine the distribution of PIs in N. attenuata to determine if they are part of the induced response in this species and if this response is ontogenetically constrained. We found that N. attenuata shoot extracts inhibited trypsin (Tryp) and chymotrypsin (Chym) activities, while root extracts inhibited Tryp, Chym, and the bacterial protease subtilisin (Sub). The highest TrypPI levels were found at midday in the source-sink transition leaf, while older or younger leaves contained lower TrypPI levels and did not show significant diurnal fluctuations. Rosette plants, bolting plants, and flowering plants all contained TrypPIs in leaves, stems, and flowers, while seed capsules, seeds, and young seedlings did not contain any PIs. PIs in N. attenuata rosette plants were induced by Manduca sexta larval feeding, methyl jasmonate (MeJA) treatment, wounding, and application of M. sexta oral secretion and regurgitant. The response to MeJA application was stronger and longer lasting than to mechanical wounding. The direction and magnitude of the systemic response to mechanical wounding or larval damage depended on the age of the leaf that was damaged and the frequency of wounding. The systemic signal for TrypPI induction appears to follow source-sink relations in the plant and to be regulated by the octadecanoid pathway. Interestingly, by the time plants reach the flowering stage, they had lost the ability to increase PI levels after MeJA treatment. We concluded that plant ontogeny constrains both constitutive and inducible PI production in N. attenuata.


Asunto(s)
Nicotiana/metabolismo , Inhibidores de Serina Proteinasa/metabolismo , Acetatos/farmacología , Animales , Quimotripsina/antagonistas & inhibidores , Quimotripsina/metabolismo , Ritmo Circadiano , Ciclopentanos/farmacología , Manduca , Oxilipinas , Extractos Vegetales/química , Extractos Vegetales/metabolismo , Brotes de la Planta/química , Brotes de la Planta/metabolismo , Inhibidores de Serina Proteinasa/biosíntesis , Subtilisina/antagonistas & inhibidores , Subtilisina/metabolismo , Nicotiana/química , Nicotiana/crecimiento & desarrollo , Tripsina/metabolismo
6.
J Cardiovasc Magn Reson ; 3(4): 349-60, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11777227

RESUMEN

Nicorandil (SG75) is a potent K+-channel activator with an additional nitro moiety. In the present study we investigated the potential mechanisms (K+-channel activation and nitric oxide [NO] release) for the effects of nicorandil on isolated perfused rat hearts during total global ischemia using 31P-nuclear magnetic resonance. After a 10-min control perfusion, hearts were subjected to treatment with nicorandil-containing (100, 300, or 1000 microM) buffer for 10 min, 15 min of total global ischemia, and 30 min of reperfusion. At high dose (10(-3) M), nicorandil reduced ATP depletion during ischemia by 26% compared with untreated hearts. Blockade of K+ channels by glibenclamide prevented this protective effect. At all doses (10(-4) to 10(-3) M), nicorandil reduced the accumulation of protons during ischemia compared with untreated hearts (pH 6.22 +/- 0.03 vs. 6.02 +/- 0.05 in untreated hearts at the end of ischemia). This effect was preserved after blockade of K+ channels by glibenclamide. Hearts treated with nitroglycerine before ischemia also showed reduced proton accumulation. Therefore, NO release accompanied by increased coronary flow before ischemia, which is caused by the nitro moiety of nicorandil and nitroglycerine treatment, results in reduced proton accumulation. During reperfusion, a pro-arrhythmic effect was observed in hearts treated with the nonpharmacologically high dose of nicorandil (1000 microM). Thus, we conclude that the effects of nicorandil are caused by the simultaneous action of both mechanisms K+-channel activation and NO release. The activation of K+ channels prevents deterioration of ATP during ischemia, whereas NO release and increased coronary flow reduce the accumulation of protons--and thus the decrease in pH--during ischemia.


Asunto(s)
Antiarrítmicos/farmacología , Circulación Coronaria/efectos de los fármacos , Gliburida/farmacología , Contracción Miocárdica/efectos de los fármacos , Nicorandil/farmacología , Canales de Potasio/efectos de los fármacos , Animales , Corazón/efectos de los fármacos , Concentración de Iones de Hidrógeno , Espectroscopía de Resonancia Magnética , Masculino , Isquemia Miocárdica/fisiopatología , Reperfusión Miocárdica , Fósforo , Ratas , Ratas Wistar
7.
Phytochemistry ; 54(6): 591-5, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10963452

RESUMEN

A novel diastereomer of ocobullenone. designated as sibyllenone, was isolated from the stem bark of mature Ocotea bullata in the course of a search for anti-inflammatory compounds from this plant. The stereostructure was established by X-ray crystallography and corroborated by NOESY analysis. Ocobullenone, obtained previously, was re-isolated and crystallised successfully for X-ray analysis, thus making possible an accurate spatial comparison of ocobullenone, iso-ocobullenone and the new stereoisomer. Tested pharmacologically for cyclooxygenase-1 and 2, and 5-lipoxygenase inhibition, sibyllenone was the only compound from O. bullata which showed good inhibitory activity towards 5-lipoxygenase.


Asunto(s)
Antiinflamatorios/aislamiento & purificación , Dioxanos/aislamiento & purificación , Lauraceae/química , Inhibidores de la Lipooxigenasa/aislamiento & purificación , Plantas Medicinales/química , Antiinflamatorios/química , Araquidonato 5-Lipooxigenasa/química , Cristalografía por Rayos X , Ciclooxigenasa 1 , Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa/química , Inhibidores de la Ciclooxigenasa/aislamiento & purificación , Dioxanos/química , Isoenzimas/antagonistas & inhibidores , Inhibidores de la Lipooxigenasa/química , Espectroscopía de Resonancia Magnética , Prostaglandina-Endoperóxido Sintasas , Estereoisomerismo
8.
Cardiovasc Res ; 43(1): 117-24, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10536696

RESUMEN

OBJECTIVE: In heart failure, cardiac energy metabolism is compromised. The failing myocardium is characterized by reduced contents of both phosphorylated (phosphocreatine) and non-phosphorylated (free) creatine content as well as decreased energy reserve via creatine kinase (creatine kinase reaction velocity). These changes may contribute to cardiac dysfunction. The purpose of the present study was to determine whether chronic feeding with high-dose dietary creatine prevents the derangement of energy metabolism and the development of left ventricular remodeling in a rat model of heart failure, i.e. post-myocardial infarction (MI). METHODS AND RESULTS: Rats were subjected to sham operation or left coronary artery ligation. Surviving rats were fed with 0% (untreated) or 3% creatine (related to weight of diet) for 8 weeks. Creatine feeding increased serum creatine levels significantly approximately 2-fold. Thereafter, hearts were isolated, perfused and left ventricular pressure-volume curves obtained. Steady state and dynamic (CK reaction velocity) high-energy phosphate metabolism was determined with 31P NMR spectroscopy. In both MI groups (treated n = 8, untreated n = 7), pressure-volume curves were shifted right- and downward compared to both sham groups (treated n = 5, untreated n = 7), i.e. creatine had no effect on left ventricular remodeling. Likewise, similar reductions of phosphocreatine, free creatine and creatine kinase reaction velocity (untreated sham 12.0 +/- 0.7 mmol/lxs; untreated MI 7.8 +/- 0.7*; treated sham 13.6 +/- 1.0; treated MI 7.2 +/- 1.1*; *p < 0.025 sham vs. MI) were found in both MI groups. CONCLUSIONS: Chronic creatine feeding of post-MI rats is ineffective in preventing the functional and energetic derangements occurring post-MI. Inspite of increased serum creatine levels, neither the normal nor the failing heart accumulates additional creatine.


Asunto(s)
Creatina/administración & dosificación , Insuficiencia Cardíaca/etiología , Infarto del Miocardio/complicaciones , Miocardio/metabolismo , Remodelación Ventricular , Adenosina Trifosfato/metabolismo , Administración Oral , Animales , Creatina/sangre , Insuficiencia Cardíaca/metabolismo , Espectroscopía de Resonancia Magnética , Infarto del Miocardio/metabolismo , Perfusión , Fosfocreatina/metabolismo , Ratas , Ratas Wistar
11.
Circulation ; 96(7): 2190-6, 1997 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-9337189

RESUMEN

BACKGROUND: In patients with heart failure due to dilated cardiomyopathy, cardiac energy metabolism is impaired, as indicated by a reduction of the myocardial phosphocreatine-to-ATP ratio, measured noninvasively by 31P-MR spectroscopy. The purpose of this study was to test whether the phosphocreatine-to-ATP ratio also offers prognostic information in terms of mortality prediction as well as how this index compares with well-known mortality predictors such as left ventricular ejection fraction (LVEF) or New York Heart Association (NYHA) class. METHODS AND RESULTS: Thirty-nine patients with dilated cardiomyopathy were followed up for 928+/-85 days (2.5 years). At study entry, LVEF and NYHA class were determined, and the cardiac phosphocreatine-to-ATP ratio was measured by localized 31P-MR spectroscopy of the anterior myocardium. During the study period, total mortality was 26%. Patients were divided into two groups, one with a normal phosphocreatine-to-ATP ratio (>1.60; mean+/-SE, 1.98+/-0.07; n=19; healthy volunteers: 1.94+/-0.11, n=30) and one with a reduced phosphocreatine-to-ATP ratio (<1.60; 1.30+/-0.05; n=20). At re-evaluation (mean, 2.5 years), 8 of 20 patients with reduced phosphocreatine-to-ATP ratios had died, all of cardiovascular causes (total and cardiovascular mortality, 40%). Of the 19 patients with normal phosphocreatine-to-ATP ratios, 2 had died (total mortality, 11%), one of cardiovascular causes (cardiovascular mortality, 5%). Kaplan-Meier analysis showed significantly reduced total (P=.036) and cardiovascular (P=.016) mortality for patients with normal versus patients with low phosphocreatine-to-ATP ratios. A Cox model for multivariate analysis showed that the phosphocreatine-to-ATP ratio and NYHA class offered significant independent prognostic information on cardiovascular mortality. CONCLUSIONS: The myocardial phosphocreatine-to-ATP ratio, measured noninvasively with 31P-MR spectroscopy, is a predictor of both total and cardiovascular mortality in patients with dilated cardiomyopathy.


Asunto(s)
Adenosina Trifosfato/metabolismo , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/mortalidad , Miocardio/metabolismo , Fosfocreatina/metabolismo , Adenosina Trifosfato/análisis , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Tablas de Vida , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Fosfocreatina/análisis , Fósforo , Valor Predictivo de las Pruebas , Pronóstico , Factores de Tiempo
12.
Crit Care Nurs Q ; 20(1): 1-13, 1997 May.
Artículo en Inglés | MEDLINE | ID: mdl-9165773

RESUMEN

This article presents an overview of the varied modes of ventilation and supportive adjuncts for the pediatric patient. Ventilatory management has changed over the past few decades with the advent of high-frequency ventilation, pressure control-inverse ratio, pressure-regulated volume control, volume support, noninvasive bi-level pressure ventilation such as BiPAP, and the emergence of adjuncts to improve oxygenation such as surfactant, extracorporeal membrane oxygenation, nitric oxide, and total and partial liquid ventilation. Ventilatory management of pediatric patients mandates an armamentarium including guided imagery and the use of speech enhancers. A multidisciplinary team approach is essential.


Asunto(s)
Respiración Artificial/métodos , Respiración Artificial/tendencias , Niño , Cuidados Críticos , Humanos , Unidades de Cuidado Intensivo Pediátrico , Enfermería Pediátrica , Respiración Artificial/enfermería
13.
Intensive Care Med ; 23(2): 187-95, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9069004

RESUMEN

OBJECTIVE: To determine the influence of selective oropharyngeal decontamination (SOD) on the rate of colonization and infection of the respiratory tract in intensive care patients requiring mechanical ventilation for more than 4 days. A financial assessment was also performed. DESIGN: Randomized, prospective, controlled study using amphotericin B, colistin sulfate (polymyxin E), and tobramycin applied to the oropharynx and systemic cefotaxime prophylaxis. SETTING: Anesthesiology intensive care unit (ICU) of a 1500-bed hospital. PATIENTS: A total of 88 patients admitted as emergencies and intubated within less than 24 h were enrolled. Fifty-eight patients received SOD and 30 patients served as controls. Randomization was in the proportion of 2 : 1 study patients to controls. INTERVENTIONS: Microbiological samples from the oropharynx and other infected sites were taken at the time of admission, then twice a week and after extubation. MEASUREMENTS AND RESULTS: With the use of SOD, colonization was significantly reduced. Furthermore, the infection rate decreased from 77% in the controls to 22% in the study patients. Staphylococcus aureus was the main potential pathogen causing colonization and pneumonia. Number of days in the ICU, duration of ventilation, and mortality were not significantly decreased. The total cost of antibiotics was reduced. Development of resistance was not observed. CONCLUSIONS: The use of SOD significantly reduced the colonization and pneumonia and the total charge for antibiotics. The length of stay in the ICU, duration of ventilation, and mortality were similar. No resistance was observed. Staphylococcus aureus was selected by SOD in some patients and the clinical relevance needs further observation.


Asunto(s)
Anfotericina B/uso terapéutico , Antibacterianos/uso terapéutico , Colistina/uso terapéutico , Infección Hospitalaria/prevención & control , Orofaringe/microbiología , Neumonía/prevención & control , Tobramicina/uso terapéutico , Adulto , Infección Hospitalaria/mortalidad , Farmacorresistencia Microbiana , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Orofaringe/efectos de los fármacos , Neumonía/mortalidad , Respiración Artificial
15.
Am J Physiol ; 269(6 Pt 1): L855-64, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8572248

RESUMEN

We demonstrate that in immortalized normal human tracheal epithelial cells (NT-1 and 56FHTE8o-) 14C-labeled glycoconjugate secretion may be regulated independently by agonists of the protein kinase A (PKA) and protein kinase C (PKC) signaling pathways. In contrast, in immortalized cystic fibrosis (CF) human tracheal epithelial cells (CFT-1 and CFT-2), regulation is defective for agonists specific for the PKA but not for the PKC pathway. To characterize the involvement of the cystic fibrosis transmembrane conductance regulator (CFTR) in regulated glycoconjugate secretion, we examined the effect of adenovirus-mediated gene transfer of CFTR to CF and control cells. Forty-eight hours after infection, at a multiplicity of infection of 50 plaque-forming units per cell, high levels of CFTR mRNA were detected by reverse transcription-polymerase chain reaction, and de novo synthesis of CFTR protein was demonstrated by immunoblotting. Gene transfer to CF cells restored defective adenosine 3',5'-cyclic monophosphate (cAMP)-dependent secretion not only of chloride but also of glycoconjugates. Taken together, these results argue for a role for CFTR in cAMP-mediated glycoconjugate secretion.


Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fibrosis Quística/metabolismo , Técnicas de Transferencia de Gen , Glicoconjugados/metabolismo , Tráquea/metabolismo , Adenoviridae/genética , Secuencia de Bases , Cloruros/fisiología , AMP Cíclico/fisiología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , ADN Complementario/metabolismo , Conductividad Eléctrica , Epitelio/metabolismo , Epitelio/patología , Vectores Genéticos , Humanos , Sondas Moleculares/genética , Datos de Secuencia Molecular , Proteína Quinasa C/metabolismo , Tráquea/patología
16.
Circulation ; 86(6): 1810-8, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1451253

RESUMEN

BACKGROUND: The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy. METHODS AND RESULTS: Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly. CONCLUSIONS: Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.


Asunto(s)
Gasto Cardíaco Bajo/metabolismo , Cardiomiopatía Dilatada/diagnóstico , Enfermedad Coronaria/diagnóstico , Metabolismo Energético , Imagen por Resonancia Magnética , Fósforo , Adulto , Anciano , Cardiomiopatía Dilatada/metabolismo , Enfermedad Coronaria/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Miocardio/metabolismo , Miocardio/patología , Fosfatos/metabolismo , Valores de Referencia
17.
Rofo ; 157(5): 452-7, 1992 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-1421185

RESUMEN

The T1 relaxation times of the phosphorus metabolites in human heart muscle measurable by 31P-MR spectra were determined in 12 individuals using a 1.5 Tesla system. Several spectra were recorded consecutively with a pulse repetition time of 1.6 s to 24 s. The T1 times of creatine phosphate (CP), of gamma-, alpha-, beta-adenosintriphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG) together with anorganic phosphate) and phosphodiester (PDE) showed mean measurements of 6.1 +/- 0.5, 5.4 +/- 0.5, 5.0 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s (M +/- SE). The accuracy of the ISIS technique was tested with a special phantom. T1 times were also measured in standard solutions (20 mM CP, 10 mM ATP); CP was 8.7 +/- 0.2 s and gamma-ATP was 9.9 +/- 0.7 s. Corrections for partially saturated 31P-MR spectra--at least for CP/ATP ratios--are relatively small.


Asunto(s)
Espectroscopía de Resonancia Magnética/métodos , Miocardio/metabolismo , Fósforo/metabolismo , 2,3-Difosfoglicerato , Adenosina Trifosfato/metabolismo , Adulto , Ácidos Difosfoglicéricos/metabolismo , Humanos , Espectroscopía de Resonancia Magnética/instrumentación , Modelos Estructurales , Organofosfatos/metabolismo , Fosfocreatina/metabolismo , Radioisótopos de Fósforo , Factores de Tiempo
18.
Magn Reson Med ; 26(2): 300-7, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1513251

RESUMEN

T1 values of phosphorus metabolites visible in human cardiac 31P-MR spectra were determined in 12 volunteers at 1.5 T. Consecutive spectra were acquired with varying pulse repetition time (TR) from 1.6 to 24 s; volume selection was achieved with ISIS. T1's of creatine phosphate (CP), [gamma-P], [alpha-P], and [beta-P]ATP, 2-3 diphosphoglycerate, and phosphodiesters were 6.1 +/- 0.5, 5.4 +/- 0.5, 5.5 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s, respectively. CP/ATP ratios showed little change with varying TR; linear regression of CP/ATP vs TR was of borderline significance (r = 0.28, P = 0.06). T1's for CP and ATP were also determined in standard solution (20 mM CP, 10 mM ATP) yielding T1CP of 8.7 +/- 0.2 and T1[gamma-P]-ATP of 9.9 +/- 0.7 s. Thus, T1's for CP and ATP were similar at 1.5 T in both human heart and standard solution. In human cardiac 31P-MR spectra, CP/ATP ratios may need little correction for partial saturation.


Asunto(s)
Espectroscopía de Resonancia Magnética , Miocardio/química , Fósforo/metabolismo , 2,3-Difosfoglicerato , Adenosina Trifosfato/análisis , Adulto , Ácidos Difosfoglicéricos/análisis , Humanos , Fosfocreatina/análisis , Fósforo/análisis , Factores de Tiempo
19.
Arzneimittelforschung ; 27(11): 2032-5, 1977.
Artículo en Inglés | MEDLINE | ID: mdl-579996

RESUMEN

The present paper indicates how to regulate the "size of mesh" in drug screening by sample size and/or by modification of the statistical procedure used. Such a regulation is demonstrated on a 2-step procedure of in vivo testing of antiviral compounds as an example, by changing the rules of decision with the parameter R0. From the computed probabilities of discarding substances with defined effectivities, curves have been drawn which allow to read off immediately sample sizes and R0-values for a desired "size of mesh".


Asunto(s)
Antivirales/farmacología , Evaluación Preclínica de Medicamentos/métodos , Probabilidad , Estadística como Asunto
20.
Z Allg Mikrobiol ; 16(1): 57-63, 1976.
Artículo en Inglés | MEDLINE | ID: mdl-184604

RESUMEN

A 2-step procedure of screening of antiviral compounds in vivo is presented on the basis of standardized methods of both experimental examination and statistical analysis. The procedure uses the "rate of protection" R as the sole criterion of activity. In the first step, requiring a total of 40 mice, compounds with significant R are detected. Drugs producing R less than 15% are discarded. Compounds eliciting R larger than or equal to 15%, without significance, are examined in a second step, using again 40 mice, to decide whether the protective activity becomes significant employing a greater number of animals. The procedure works with relatively less expense with regard of the number of animals used and the time required. The procedure can be applied to test systems based on lethal infections as well as to test models for which the use of the "rate of protection" is relevant.


Asunto(s)
Antivirales , Evaluación Preclínica de Medicamentos/métodos , Mengovirus/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Infecciones por Enterovirus/prevención & control , Ratones
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