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1.
Front Pharmacol ; 8: 466, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28855870

RESUMEN

Phytochemical studies are seeking new alternatives to prevent or treat cancer, including different types of leukemias. Campomanesia adamantium, commonly known as guavira or guabiroba, exhibits pharmacological properties including antioxidant, antimicrobial, and antiproliferative activities. Considering the anticancer potential of this plant species, the aim of this study was to evaluate the antileukemic activity and the chemical composition of aqueous extracts from the leaves (AECL) and roots (AECR) of C. adamantium and their possible mechanisms of action. The extracts were analyzed by LC-DAD-MS, and their constituents were identified based on the UV, MS, and MS/MS data. The AECL and AECR showed different chemical compositions, which were identified as main compounds glycosylated flavonols from AECL and ellagic acid and their derivatives from AECR. The cytotoxicity promoted by these extracts were evaluated using human peripheral blood mononuclear cells and Jurkat leukemic cell line. The cell death profile was evaluated using annexin-V-FITC and propidium iodide labeling. Changes in the mitochondrial membrane potential, the activity of caspases, and intracellular calcium levels were assessed. The cell cycle profile was evaluated using propidium iodide. Both extracts caused concentration-dependent cytotoxicity only in Jurkat cells via late apoptosis. This activity was associated with loss of the mitochondrial membrane potential, activation of caspases-9 and -3, changes in intracellular calcium levels, and cell cycle arrest in S-phase. Therefore, the antileukemic activity of the AECL and AECR is mediated by mitochondrial dysfunction and intracellular messengers, which activate the intrinsic apoptotic pathway. Hence, aqueous extracts of the leaves and roots of C. adamantium show therapeutic potential for use in the prevention and treatment of diseases associated the proliferation of tumor cell.

2.
J Environ Qual ; 37(4): 1567-74, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18574189

RESUMEN

Vegetated buffers strips typically have limited ability to reduce delivery of dissolved phosphorus (DP) from agricultural fields to surface waters. A field study was conducted to evaluate the ability of buffer strips enhanced with drinking water treatment residuals (WTRs) to control runoff P losses from surface-applied biosolids characterized by high water-extractable P (4 g kg(-)(1)). Simulated rainfall (62.4 mm h(-1)) was applied to grassed plots (3 m x 10.7 m including a 2.67 m downslope buffer) surface-amended with biosolids at 102 kg P ha(-1) until 30 min of runoff was collected. With buffer strips top-dressed with WTR (20 Mg ha(-1)), runoff total P (TP = 2.5 mg L(-1)) and total DP (TDP = 1.9 mg L(-1)) were not statistically lower (alpha = 0.05) compared to plots with unamended grass buffers (TP = 2.7 mg L(-1); TDP = 2.6 mg L(-1)). Although the applied WTR had excess capacity (Langmuir P maxima of 25 g P kg(-1)) to sorb all runoff P, kinetic experiments suggest that sheet flow travel time across the buffers ( approximately 30 s) was insufficient for significant P reduction. Effective interception of dissolved P in runoff water by WTR-enhanced buffer strips requires rapid P sorption kinetics and hydrologic flow behavior ensuring sufficient runoff residence time and WTR contact in the buffer. Substantial phosphate-adsorbent contact opportunity may be more easily achieved by incorporating WTRs into P-enriched soils or blending WTRs with applied P sources.


Asunto(s)
Fósforo/aislamiento & purificación , Aguas del Alcantarillado , Abastecimiento de Agua/análisis , Cinética , Lluvia
3.
Proc Natl Acad Sci U S A ; 97(21): 11377-82, 2000 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-11027338

RESUMEN

Exons of three genes were identified within the 85-kilobase tandem triplication unit of the slow Wallerian degeneration mutant mouse, C57BL/Wld(S). Ubiquitin fusion degradation protein 2 (Ufd2) and a previously undescribed gene, D4Cole1e, span the proximal and distal boundaries of the repeat unit, respectively. They have the same chromosomal orientation and form a chimeric gene when brought together at the boundaries between adjacent repeat units in Wld(S). The chimeric mRNA is abundantly expressed in the nervous system and encodes an in-frame fusion protein consisting of the N-terminal 70 amino acids of Ufd2, the C-terminal 302 amino acids of D4Cole1e, and an aspartic acid formed at the junction. Antisera raised against synthetic peptides detect the expected 43-kDa protein specifically in Wld(S) brain. This expression pattern, together with the previously established role of ubiquitination in axon degeneration, makes the chimeric gene a promising candidate for Wld. The third gene altered by the triplication, Rbp7, is a novel member of the cellular retinoid-binding protein family and is highly expressed in white adipose tissue and mammary gland. The whole gene lies within the repeat unit leading to overexpression of the normal transcript in Wld(S) mice. However, it is undetectable on Northern blots of Wld(S) brain and seems unlikely to be the Wld gene. These data reveal both a candidate gene for Wld and the potential of the Wld(S) mutant for studies of ubiquitin and retinoid metabolism.


Asunto(s)
Proteínas Fúngicas/genética , Nicotinamida-Nucleótido Adenililtransferasa , Proteínas/genética , Proteínas Recombinantes de Fusión/genética , Proteínas de Unión al Retinol/genética , Proteínas de Saccharomyces cerevisiae , Degeneración Walleriana , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sistema Nervioso Central/metabolismo , ADN Complementario , Exones , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Sistema Nervioso Periférico/metabolismo , ARN Mensajero/genética , Proteínas Celulares de Unión al Retinol , Homología de Secuencia de Aminoácido , Enzimas Ubiquitina-Conjugadoras
4.
Comb Chem High Throughput Screen ; 1(3): 143-53, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10500773

RESUMEN

Combinatorial libraries are an important tool for lead discovery in the pharmaceutical industry. Advances in high throughput screening coupled with combinatorial chemistry can significantly reduce the time to find lead compounds. A major difficulty in developing large combinatorial libraries is the ability to identify active compounds. This paper describes a rapid and sensitive encoding/decoding methodology that utilizes stable isotopes and mass spectrometry. The ability of mass spectrometry to precisely determine the intensity of isotopic abundances provides a unique encoding strategy employing synthetically generated ratios of stable isotopes in a compound as the code. The application of ratio encoding is demonstrated using peptoid and imidazole chemistries. Supporting data demonstrate that the incorporation of one or more stable isotopes using unique-predetermined ratios can encode chemical libraries. In addition, the presence of a unique isotopic pattern in a ligand can facilitate the pharmacokinetic analysis. Isotope incorporation into a compound and subsequently into its metabolites reliably distinguishes products from other molecules in the mass spectrum. This is illustrated by metabolic analyses of peptoid and imidazole compounds.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Isótopos/análisis , Espectrometría de Masas/métodos , Biblioteca de Péptidos , Secuencia de Aminoácidos , Animales , Sistema Enzimático del Citocromo P-450/metabolismo , Industria Farmacéutica/métodos , Imidazoles/síntesis química , Imidazoles/química , Microsomas Hepáticos/metabolismo , Datos de Secuencia Molecular , Isótopos de Nitrógeno , Péptidos/química , Péptidos/metabolismo , Peptoides , Proteínas Proto-Oncogénicas pp60(c-src)/química , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo , Ratas , Investigación , Programas Informáticos , Dominios Homologos src
5.
Holist Nurs Pract ; 11(4): 1-26, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9274170

RESUMEN

Interventions utilized by nurses to manage "difficult" patients and outcomes indicating successful interventions were investigated. Themes included getting the difficult patient label, difficult patient behaviors, reflecting on the label and passing it on, coping with a difficult patient, interventions that worked, and interventions that did not work. Clues indicating that patient behavior was changing were also identified.


Asunto(s)
Relaciones Enfermero-Paciente , Atención de Enfermería , Rol del Enfermo , Adaptación Psicológica , Adulto , Investigación en Enfermería Clínica , Demografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Estereotipo
6.
Ann Allergy Asthma Immunol ; 79(1): 85-8, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9236507

RESUMEN

INTRODUCTION: During the 1970s, scientists suggested that the growing use of chlorofluorocarbons (CFCs) was contributing to depletion of the stratospheric ozone layer with potentially harmful results. A committee on the ozone layer organized the preparation of the Montreal Protocol. This protocol mandated the cessation of production and use of CFCs by January 1, 1996. The primary exemption to this ban is for the use of CFCs as propellants in metered dose inhalers (MDIs) for the treatment of asthma. Suitable replacement hydrofluoroalkane (HFA) propellants, such as HFA-134a, for use in MDIs have been identified. Albuterol, a selective beta-adrenergic agonist, currently widely available for inhalation asthma therapy, has been reformulated in HFA-134a (Proventil HFA). OBJECTIVE; To compare the efficacy of Proventil HFA to Ventolin, Proventil, and placebo (HFA-134a) MDI in protecting asthmatic patients from exercise-induced bronchoconstriction. METHODS: This was a randomized, single-blind, placebo-controlled, 4-period crossover study of asthmatic patients with documented exercise-induced broncho-constriction. Twenty patients self administered two puffs of either Proventil HFA, Ventolin, Proventil or placebo, from an MDI, 30 minutes prior to performing a standardized exercise challenge at the study site. Spirometry was performed predose and 5, 10, 15, 30, 45, 60, 75, and 90 minutes after completion of the exercise challenge. Heart rate and blood pressure were measured just prior to spirometry and a 12-lead ECG was performed 15 minutes after completion of the exercise challenge for measurement of the QT corrected interval. RESULTS: The primary efficacy variable was the smallest percent change from the predose FEV1 following exercise. The smallest percent change from predose FEV1 for Proventil HFA was 2.0 +/- 9.9 SD, similar to the 2.0 +/- 11.4 SD for Ventolin, and the 3.6 +/- 10.2 SD for Proventil. The smallest percent change from predose FEV1 for each of the active treatments was significantly different from placebo, -23.7 +/- 14.5. Twelve of the patients had a > or = 20% fall in FEV1 post-exercise with placebo pretreatment, but only 1, 1, and 0 had > or = 20% FEV1 falls after treatment with Proventil HFA, Ventolin, and Proventil respectively. Changes in heart rate, blood pressure and QT corrected interval were similar for the three active treatments following exercise. CONCLUSIONS: Proventil HFA provides protection against exercise-induced bronchoconstriction comparable to Ventolin and Proventil and protection superior to placebo. Proventil HFA has a safety profile similar to Ventolin when used to prevent exercise-induced bronchoconstriction.


Asunto(s)
Agonistas Adrenérgicos beta/uso terapéutico , Albuterol/uso terapéutico , Asma Inducida por Ejercicio/prevención & control , Broncoconstricción/fisiología , Broncodilatadores/uso terapéutico , Hidrocarburos Fluorados/uso terapéutico , Adolescente , Adulto , Asma Inducida por Ejercicio/fisiopatología , Broncoconstricción/efectos de los fármacos , Tolerancia a Medicamentos , Femenino , Humanos , Masculino
7.
Metabolism ; 46(6): 619-24, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9186295

RESUMEN

It has previously been shown that the n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (20:5(n-3)) and docosahexaenoic acid (22:6(n-3)) possess antiinflammatory properties and can interfere with immune functions. To evaluate whether this would affect resistance to infection, we studied the influence of different types of fatty acids (FAs) on experimental tuberculosis in an animal model. Three groups of 26 weanling guinea pigs were fed isocaloric diets with 26 cal% fat that differed in FA composition with respect to saturated FAs, linoleic acid (18:2(n-6)), eicosapentaenoic acid (20:5(n-3)), and docosanexaenoic acid (22:6(n-3)) as follows: (1) reference (REF) group: 14.8 cal% saturated FAs and 2.8 cal% linoleic acid; (2) n-6 group: 4.6 cal% saturated FAs and 15.4 cal% linoleic acid; (3) n-3 group: 6.3 cal% saturated FAs, 10 cal% linoleic acid, 1.4 cal% eicosapentaenoic acid, and 0.9 cal% docosahexaenoic acid. After 13 weeks, 18 animals from each group were intramuscularly injected with 180 colony-forming units (CFU) Mycobacterium tuberculosis strain H37Rv. Eight noninfected animals per group served as controls. Seven weeks later, the mean number of mycobacteria recovered from the spleens of the n-3 group (log 4.34 CFU, standard error of the mean [SEM], 0.12) was significantly higher than from the REF group (log 3.90 CFU; SEM, 0.15) and the n-8 group (log 3.93 CFU; SEM, 0.13; P < .05). In addition, the Root Index of Virulence (RIV) showed the most pronounced progression of the disease in the n-3 group. The mean size of the tuberculin reaction was larger in the n-3 group than in the other groups (P < .05). There was no significant difference between the n-6 group and the REF group. We conclude that supplementing the diet with n-3 FAs eicosapentaenoic acid and docosahexaenoic acid can affect resistance to M tuberculosis, whereas supplementing with n-6 FAs does not.


Asunto(s)
Grasas Insaturadas en la Dieta/farmacología , Ácidos Grasos Omega-3/farmacología , Ácidos Grasos Insaturados/farmacología , Tuberculosis/fisiopatología , Animales , Ingestión de Energía , Ácidos Grasos no Esterificados/sangre , Ácidos Grasos Omega-6 , Cobayas , Inmunidad Innata , Masculino , Mycobacterium tuberculosis/aislamiento & purificación , Pruebas Cutáneas , Bazo/microbiología , Tuberculosis/inmunología , Aumento de Peso
8.
Med Klin (Munich) ; 92 Suppl 3: 26-8, 1997 Sep 15.
Artículo en Alemán | MEDLINE | ID: mdl-9417492

RESUMEN

BACKGROUND: Previous examinations have demonstrated decreased selenium levels in serum and full blood in patients with myocardial infarction. PATIENTS AND METHOD: 28 patients received a selenium treatment additional to the usual treatment of myocardial infarction. 19 patients with myocardial infarction with no supplementary selenium treatment served as a control group. Selenium levels in serum, full blood and urine were measured and the complications of the myocardial infarction documanted. RESULTS: There was a significant increase of serum and full blood selenium and glutathione peroxidase levels under i.v. selenium therapy in the acute phase of myocardial infarction (first to third day). Left heart failure more rarely occurred in the selenium group (20%) than in control patients (57%). Acute tachycardial cardiac rhythm disturbances such as ventricular extrasystoles and couplets diminished in both groups; ventricular extrasystoles decreased in the selenium group. CONCLUSIONS: Selen should be substituted in patients with acute myocardial infarction and decreased selen levels. It would be useful to carry out a prospective double-blind study.


Asunto(s)
Infarto del Miocardio/tratamiento farmacológico , Selenito de Sodio/administración & dosificación , Administración Oral , Anciano , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Electrocardiografía/efectos de los fármacos , Femenino , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Infarto del Miocardio/sangre , Estudios Prospectivos , Selenio/sangre , Resultado del Tratamiento
9.
Microsc Res Tech ; 28(2): 141-8, 1994 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-8054663

RESUMEN

In respiratory epithelium, the mucus is densely packed inside the secretory granules (SG) of secretory cells (SC) before being released by exocytosis in the airway lumen. We have previously shown that the frog palate is a representative model of respiratory epithelium and that rapid cryofixation is a very effective technique in preserving the integrity of the mucus SG. The concentration of phosphorus (P), sulphur (S), and calcium (Ca) were analysed inside the SG of the SC of frog palate after quick freezing, cryosubstitution, and embedding in Lowicryl resin at low temperature. The experiments were carried out using X-ray microanalysis conducted with energy dispersive spectrometry (EDS) at 100 kV. The quantitation was carried out using the continuum method with reference to Agar standards. The cryofixation permitted us to distinguish two types of SG depending on whether they were electron dense (serous cells) or electron-lucent (mucous cells). A significant (P < 0.001) difference in the S concentration was observed between the individual serous (239 +/- 79 mmol.kg-1) and the mucous SG (161 +/- 48 mmol.kg-1). No significant difference could be identified in the Ca concentration between the two SG phenotypes. In the serous SG, the P content was high (41 +/- 17 mmol.kg-1) compared with the mucous SG where it was not measurable. The comparison of the three element concentrations in each type of secretory cells showed that significant differences in concentration of S and Ca concentration could be observed from one SC cell to another.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Calcio/análisis , Microanálisis por Sonda Electrónica , Hueso Paladar/química , Fósforo/análisis , Azufre/análisis , Animales , Criopreservación , Gránulos Citoplasmáticos/química , Gránulos Citoplasmáticos/ultraestructura , Masculino , Rana esculenta , Sistema Respiratorio/química , Sistema Respiratorio/ultraestructura
10.
Infection ; 22(2): 106-12, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-8070921

RESUMEN

In the present study eicosanoid synthesis was studied in macrophages of guinea pigs fed different amounts of (n-6)- and (n-3)-polyunsaturated fatty acids (PUFA). Three groups of weanling guinea pigs were fed by isocaloric diets differing only in their contents of PUFA: controls with 2.8 Cal% of linoleic acid (LA; 18:2(n-6)); (n-6)-rich fed animals with 15.4 Cal% of LA; and (n-3)-rich fed animals with 10.1 Cal% of LA, 1.4 Cal% of eicosapentaenoic acid (20:5(n-3)) and docosahexaenoic acid (22:6(n-3)). After 13 weeks half the number of animals from each group was infected i.m. by 180 colony forming units of Mycobacterium tuberculosis strain H37Rv. Seven weeks after infection the release of leukotriene (LT)B4 and prostaglandin (PG)E2 was quantified in calcium ionophore stimulated whole blood, peritoneal macrophage cultures and alveolar macrophages by immunoassays after high performance liquid chromatography. Synthesis of LTB4 and PGE2 was found to be reduced in (n-3)-rich fed guinea pigs (p < 0.05), and equivalent between controls and (n-6)-rich fed animals. Controls and (n-6)-rich fed animals showed the same mycobacterial counts in the spleen whereas (n-3)-rich fed guinea pigs demonstrated an increased number of mycobacteria (p < 0.05). Our results demonstrate that an increased dietary intake of (n-3)-PUFA suppress LTB4 and PGE2 synthesis. The increased number of M. tuberculosis found in the spleens of (n-3)-rich fed animals could represent persistence of the experimental infection. It may be speculated that a functional relationship exists between the two findings.


Asunto(s)
Dinoprostona/biosíntesis , Modelos Animales de Enfermedad , Ácidos Grasos Omega-3/uso terapéutico , Leucotrieno B4/biosíntesis , Tuberculosis/dietoterapia , Animales , Recuento de Colonia Microbiana , Dinoprostona/sangre , Evaluación Preclínica de Medicamentos , Ácidos Grasos Omega-3/farmacología , Cobayas , Leucotrieno B4/sangre , Macrófagos Alveolares/efectos de los fármacos , Macrófagos Alveolares/metabolismo , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/metabolismo , Masculino , Estado Nutricional , Bazo/microbiología , Tuberculosis/metabolismo , Tuberculosis/microbiología
11.
J Healthc Qual ; 14(2): 30-2, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-10119887

RESUMEN

The home healthcare staff nurse faces formidable challenges that can be met only by an extraordinary commitment to quality care. Functioning autonomously much of the time, the home healthcare nurse must act as the client's case manager. Coordination of multiple services and extensive client education are vital to positive outcomes, and intervention decisions must be based on a holistic view of the client's needs and environment. Reimbursement issues under Medicare often conflict with the delivery of high-quality care. To achieve the goals of the home healthcare agency and perform optimally, the home healthcare nurse needs a supportive QA program and frequent peer review procedures.


Asunto(s)
Servicios de Atención de Salud a Domicilio/normas , Personal de Enfermería , Planificación de Atención al Paciente/normas , Garantía de la Calidad de Atención de Salud , Servicios de Atención de Salud a Domicilio/organización & administración , Proceso de Enfermería , Revisión por Pares , Estados Unidos
12.
Am J Clin Nutr ; 54(2): 386-94, 1991 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1858702

RESUMEN

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P less than 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine.


Asunto(s)
Betaína/farmacología , Dieta , Metionina/análogos & derivados , Metionina/metabolismo , Adulto , Betaína/administración & dosificación , Betaína/orina , Isótopos de Carbono , Cistina/administración & dosificación , Deuterio , Humanos , Cinética , Masculino , Metionina/administración & dosificación , Metionina/sangre , Metilación , Necesidades Nutricionales
13.
J Hered ; 82(4): 302-4, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1880393

RESUMEN

In barley, a heavily self-fertilizing species (approximately 99%), most outcrosses occur between plants that grow closely adjacent to each other. Outcrosses have been detected only rarely between plants that are separated by a meter or more. In this article we present evidence that outcrosses can occur at distances up to 60 m and we discuss the implications of this longer-distance pollen migration on the maintenance of the genetic integrity of pedigreed stocks and experimental populations.


Asunto(s)
Hordeum/genética , Polen , Cruzamientos Genéticos , Reproducción
14.
Gastroenterol Clin Biol ; 15(3): 187-93, 1991.
Artículo en Francés | MEDLINE | ID: mdl-1710587

RESUMEN

Telemetric shuttles for the in vivo investigation of the gastrointestinal tract have been available for sometime. We describe herein the use of a new shuttle model whose original features include: a) continuous, real time transmission of its location in the small bowel and accurate measurement of the gut length, b) controlled release of 1 ml of a given substance at any chosen site, allowing detailed investigation of intestinal absorption at different levels of the small bowel under physiological conditions. Small bowel length was measured in dogs using the shuttle and was later compared to the actual small gut length measured in the same animals at laparotomy. The telemetric measurements appeared to closely match the direct operative measurements. Insulin absorption from the canine small bowel was then investigated releasing different dosages of insulin together with the pancreatic enzyme inhibitors Soybean and Aprotinine and a surfactant (5-methoxysalicylate). By adjusting the dose of insulin released, the type of adjuvant substance delivered with it and the site of release in the small bowel, we have been able to precisely define the conditions of insulin absorption. Insulin as such is exclusively absorbed in the ileum when released in doses of 500 IU or higher and mixed with aprotinine. For absorption to take place the solution delivered by the shuttle needs to have the correct pH and natremic concentration.


Asunto(s)
Insulina/fisiología , Absorción Intestinal/fisiología , Intestino Delgado/fisiología , Telemetría/métodos , Animales , Aprotinina/farmacología , Glucemia/análisis , Perros , Relación Dosis-Respuesta a Droga , Éteres de Hidroxibenzoatos , Insulina/sangre , Absorción Intestinal/efectos de los fármacos , Salicilatos/farmacología , Aceite de Soja/farmacología , Telemetría/instrumentación
15.
Am J Physiol ; 258(5 Pt 1): E790-8, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2185662

RESUMEN

Methionine (Met) conservation in healthy young adult men (4/diet group) was explored by supplying one of the following three L-amino acid based diets: 1) adequate Met but no cystine; 2) neither Met nor cystine; or 3) no Met but cystine supplementation. After 5 days, subjects received a continuous intravenous infusion of L-[1-13C; methyl-2H3]Met for 5 h while the diet was given as small isocaloric isonitrogenous meals. Estimates were made of rates of Met incorporation into protein synthesis (S) and release from body proteins (B), transmethylation (TM), remethylation of homocysteine (RM), and transsulfuration (TS). For the adequate Met diet, the rates were S = 24 +/- 2, B = 18 +/- 1, TM = 12.4 +/- 1.7, RM = 4.7 +/- 1.1, and TS = 7.6 +/- 0.6 (SE) mumol.kg-1.h-1. The sulfur amino acid-devoid diet significantly (P less than 0.05) reduced S, TM, RM, and TS. Supplementation of this diet with cystine reduced Met oxidation (P = 0.05). Therefore, two loci are quantitatively important regulatory points in Met conservation in vivo: 1) the distribution of Met between the pathways of protein anabolism and TM (Met locus) and 2) the distribution of homocysteine between RM and TS (homocysteine locus).


Asunto(s)
Cistina/metabolismo , Metionina/metabolismo , Adulto , Isótopos de Carbono , Cistina/sangre , Deuterio , Dieta , Humanos , Marcaje Isotópico/métodos , Masculino , Metionina/sangre , Técnica de Dilución de Radioisótopos
16.
J Biol Chem ; 264(27): 15850-5, 1989 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-2777767

RESUMEN

Human plasma glutathione peroxidase (GSHPx) has been shown to be a glycosylated selenoprotein distinct enzymatically, structurally, and antigenically from known cellular glutathione peroxidases. The extracellular location of the enzyme and the fact that it is glycosylated suggested that it is a secreted protein. Utilizing mutually non-cross-reactive antibodies to human cellular and plasma GSHPx, we conducted a search to determine the tissue of origin for plasma GSHPx. The cells screened were endothelial cells because they are the main source of extracellular superoxide dismutase, HL-60 cells (myeloid cell line) because they are the main source of extracellular H2O2, and Hep G2 cells (hepatic cell line) because they are the source of many plasma proteins. Human umbilical vein endothelial cells were metabolically labeled with either [35S]methionine or [75Se]selenious acid, and HL-60 cells and Hep G2 cells were metabolically labeled with [75Se]selenious acid. Proteins were immunopurified from the labeled cells and their media with either anti-red blood cell (RBC) GSHPx IgG or with anti-plasma GSHPx IgG. Utilizing anti-RBC GSHPx IgG, only the cellular form of the enzyme was precipitated from all the cells tested but not from their media. When anti-plasma GSHPx IgG was applied to the cells and their media, a selenoprotein was precipitated only from the media of Hep G2 cells. When Hep G2 cells were incubated in the presence of the carboxylic ionophore monensin, an intracellular selenoprotein could be detected using anti-plasma GSHPx IgG. The precipitation of the cellular form from all three cell types was partially inhibited by preincubation of the anti-RBC GSHPx IgG with purified RBC GSHPx while the precipitation of the selenoprotein from the medium of Hep G2 cells by anti-plasma GSHPx IgG was prevented by preincubation of the antibody with purified plasma GSHPx. We suggest that plasma GSHPx is synthesized by and secreted from hepatic cells. This is, to the best of our knowledge, the only known selenoprotein with a defined function that has been shown to be synthesized for secretion by mammalian cells.


Asunto(s)
Glutatión Peroxidasa/sangre , Selenio/farmacología , Línea Celular , Electroforesis en Gel de Poliacrilamida , Endotelio Vascular/enzimología , Eritrocitos/enzimología , Glutatión Peroxidasa/aislamiento & purificación , Humanos , Peso Molecular , Oxidación-Reducción , Ácido Selenioso
17.
18.
Ann Surg ; 207(4): 421-9, 1988 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3128190

RESUMEN

A cross-over design study was used to examine the metabolic consequences of enteral feeding for 48 to 96 hours with either a branched-chain amino acid (BCAA)-enriched (44% BCAA) or a conventional egg protein formulation in 12 severely burned adult patients. A stable isotope labeled leucine (L-1-13C-leucine) tracer approach was used to measure leucine flux and oxidation and to estimate rates of whole body protein synthesis and breakdown. Additionally, 15N2-urea and 6,6-2H-glucose were administered to assess the status of urea and glucose kinetics with these two nutritional treatments. Average patient age was 54 years, and average burn surface area was 36%. Studies were conducted at an average of 25 days postburn. Leucine flux and oxidation were significantly (p less than 0.01, by paired t-test) elevated with BCAA feeding as compared to the egg protein formulation. However, there were no significant differences in the rates of leucine incorporation into, or release from, proteins (p greater than 0.05) between the two dietary periods. Mean rates of body protein synthesis and breakdown for each diet were about twice the rates reported for healthy young adults. Apparent nitrogen balance measurements were not statistically different (p greater than 0.1) between the two diet periods. Furthermore, urea and glucose kinetics failed to show significant differences between the two diet periods. It appears from these results that the major consequences of increased intake of leucine from the BCAA formula is an enhanced rate of leucine oxidation. In conclusion, (1) the availability of BCAAs is not rate-limiting for enhanced protein synthesis in burn patients, and (2) the use of enriched BCAA formulas in burn therapy does not appear to offer advantages over a routinely used enteral egg protein formula, at least based on the present determinations.


Asunto(s)
Aminoácidos de Cadena Ramificada/administración & dosificación , Quemaduras/metabolismo , Nutrición Enteral , Alimentos Formulados , Leucina/metabolismo , Quemaduras/terapia , Proteínas del Huevo/administración & dosificación , Metabolismo Energético , Glucosa/metabolismo , Humanos , Persona de Mediana Edad , Urea/metabolismo
20.
Infusionsther Klin Ernahr ; 14 Suppl 1: 53-64, 1987 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-3106213

RESUMEN

Carbohydrates and polyols are essential constituents of intravenous nutrition. In order to better understand the problems associated with the supply of energy sources, the physiology of enteral nutrition will be covered and compared with intravenous nutrition. This review article will deal with the metabolic actions of glucose and xylitol and derive therapeutical consequences for their intravenous use during different illnesses.


Asunto(s)
Solución Hipertónica de Glucosa/administración & dosificación , Glucosa/administración & dosificación , Nutrición Parenteral Total , Xilitol/administración & dosificación , Alanina Transaminasa/metabolismo , Aspartato Aminotransferasas/metabolismo , Bilirrubina/metabolismo , Glucemia/metabolismo , Humanos , Insulina/metabolismo , Metabolismo de los Lípidos , Tasa de Depuración Metabólica , Vía de Pentosa Fosfato , Cuidados Posoperatorios , Sepsis/terapia , Heridas y Lesiones/terapia , Xilitol/metabolismo
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