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1.
Health Technol Assess ; 11(51): iii-iv, 1-164, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18021578

RESUMEN

OBJECTIVES: To evaluate the clinical effectiveness and cost-effectiveness of proton pump inhibitors (PPIs) in the prevention and treatment of acute upper gastrointestinal (UGI) haemorrhage, as well as to compare this with H2-receptor antagonist (H2RA), Helicobacter pylori eradication (in infected patients) or no therapy, for the prevention of first and/or subsequent bleeds among patients who continue to use non-steroidal anti-inflammatory drugs (NSAIDs). Also to evaluate the clinical effectiveness of PPI therapy, compared with other treatments, for the prevention of subsequent bleeds in patients who had previously experienced peptic ulcer (PU) bleeding. DATA SOURCES: Electronic databases and major conference proceedings were searched up to February 2006. REVIEW METHODS: Data were collected from the systematic reviews addressing each research objective. These were then entered into an economic model to compare the costs and quality-adjusted life-days of alternative management strategies over a 28-day period for patients who have had UGI bleeding. A Markov model with a Monte Carlo simulation used data from the systematic reviews to identify the most cost-effective treatment strategy for the prevention of UGI bleeding (first and subsequent) among NSAID users using an outcome of costs per quality-adjusted life-years (QALYs) over a lifetime from age 50 years. RESULTS: PPI treatment initiated after endoscopic diagnosis of PU bleeding significantly reduced re-bleeding and surgery compared with placebo or H2RA. Although there was no evidence of an overall effect of PPI treatment on all-cause mortality, PPIs significantly reduced mortality in subgroups when studies conducted in Asia were examined in isolation or when the analysis was confined to patients with high-risk endoscopic findings. PPI treatment initiated prior to endoscopy in UGI bleeding significantly reduced the proportion of patients with stigmata of recent haemorrhage (SRH) at index endoscopy compared with placebo or H2RA, but there was no evidence that PPI treatment affected clinically important outcomes. Giving oral PPI both before and after endoscopy, with endoscopic haemostatic therapy (EHT) for those with major SRH, is preferred to all others on cost-effectiveness grounds at any threshold over 25,000 pounds per QALY, even if only short-term effects are taken into account, and at any threshold over 200 pounds per life-year gained if long-term effects are included. The risk of NSAID-induced endoscopic gastric and duodenal ulcers was reduced by standard doses of PPI and misoprostol, and double doses of H2RAs. Standard doses of H2RAs reduced the risk of endoscopic duodenal ulcers. PPIs reduced NSAID-induced dyspepsia. PPIs were superior to misoprostol in preventing recurrence of NSAID-induced endoscopic duodenal ulcers, but PPIs were comparable to misoprostol in preventing the recurrence of NSAID-induced endoscopic gastric ulcers. Full-dose misoprostol reduced bleeding, perforation or gastric outlet obstruction due to NSAID-induced ulcers, but misoprostol was poorly tolerated and associated with frequent adverse effects. H. pylori eradication treatment was equally effective with PPI treatment for the primary or secondary prevention of endoscopic ulcers in NSAID users. H. pylori eradication treatment was more effective than placebo for the primary prevention of endoscopic PU and for the prevention of re-bleeding from PU in NSAID users. With regard to primary and secondary prevention of bleeding PU in NSAID users, the two most cost-effective strategies are H. pylori eradication alone, and H. pylori eradication followed by misoprostol (substituted by a PPI, if misoprostol is not tolerated) at an additional 4810 pounds per QALY. In patients who had previously experienced a bleed from a PU, re-bleeding was less frequent after H. pylori eradication therapy than after non-eradication antisecretory therapy, whether or not the latter was combined with long-term maintenance antisecretory therapy. CONCLUSIONS: PPI treatment compared with placebo or H2RA reduces mortality following PU bleeding among patients with high-risk endoscopic findings, and reduces re-bleeding rates and surgical intervention. PPI treatment initiated prior to endoscopy in UGI bleeding significantly reduces the proportion of patients with SRH at index endoscopy but does not reduce mortality, re-bleeding or the need for surgery. The strategy of giving oral PPI before and after endoscopy, with EHT for those with major SRH, is likely to be the most cost-effective. Treatment of H. pylori infection was found to be more effective than antisecretory therapy in preventing recurrent bleeding from PU. H. pylori eradication alone or eradication followed by misoprostol (with switch to PPI, if misoprostol is not tolerated) are the two most cost-effective strategies for preventing bleeding ulcers among H. pylori-infected NSAID users, although the data cannot exclude PPIs also being cost-effective. Further large randomised controlled trials are needed to address areas such as PPI administration prior to endoscopic diagnosis, different doses and administration of PPIs, as well as the primary and secondary prevention of UGI bleeding.


Asunto(s)
Antagonistas de los Receptores H2 de la Histamina/uso terapéutico , Úlcera Péptica Hemorrágica/tratamiento farmacológico , Inhibidores de la Bomba de Protones/uso terapéutico , Tracto Gastrointestinal Superior/efectos de los fármacos , Enfermedad Aguda , Anciano , Antiinflamatorios no Esteroideos/efectos adversos , Antiinflamatorios no Esteroideos/uso terapéutico , Congresos como Asunto , Análisis Costo-Beneficio , Bases de Datos Bibliográficas , Úlcera Duodenal/complicaciones , Endoscopía Gastrointestinal , Hemorragia Gastrointestinal/tratamiento farmacológico , Hemorragia Gastrointestinal/economía , Hemorragia Gastrointestinal/prevención & control , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/efectos de los fármacos , Antagonistas de los Receptores H2 de la Histamina/economía , Humanos , Persona de Mediana Edad , Úlcera Péptica Hemorrágica/economía , Úlcera Péptica Hemorrágica/prevención & control , Inhibidores de la Bomba de Protones/economía , Años de Vida Ajustados por Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento
2.
Cochrane Database Syst Rev ; (4): CD002301, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11687157

RESUMEN

BACKGROUND: Studies have also shown that NUD patients have higher scores of anxiety, depression, neurotism, chronic tension, hostility, hypochondriasis, and tendency to be more pessimistic when compared with the community controls. OBJECTIVES: This review aims to determine the effectiveness of psychological interventions including psychotherapy, psychodrama, cognitive behavioral therapy, relaxation therapy, guided imagery or hypnosis in the improvement of either individual or global dyspepsia symptom scores and also quality of life scores patients with non-ulcer dyspepsia (NUD). SEARCH STRATEGY: Trials were located through electronic searches of the Cochrane Controlled Trials Register (CCTR), MEDLINE, EMBASE, CINAHL and PsycLIT, using appropriate subject headings and text words and searching bibliographies of retrieved articles. SELECTION CRITERIA: All randomised controlled trials (RCTs) or quasi-randomised studies assessing the effectiveness of psychological interventions (including psychotherapy, psychodrama, cognitive behavioural therapy, relaxation therapy, guided imagery or hypnosis) for non-ulcer dyspepsia (NUD). DATA COLLECTION AND ANALYSIS: Data were collected on individual, global dyspepsia symptom scores, as well as measures of quality of life (QoL) scores and adverse effects. MAIN RESULTS: The three trials identified showed that there was improvement in the dyspepsia symptom scores at the end of treatment and one trial showed improvement in the psychological parameters. However, meta-analysis was not possible as these trials used different psychological interventions and two of the trials only reported mean change in symptoms and did not give standard deviations of this change. REVIEWER'S CONCLUSIONS: Psychological intervention in the form of psychodynamic psychotherapy and cognitive behavioral therapy may be useful in the treatment of NUD. However, we need more trials to assess dyspepsia symptom scores and also psychological intervention in order to give us a clearer picture of the role of psychological intervention in NUD.


Asunto(s)
Dispepsia/psicología , Dispepsia/terapia , Psicoterapia , Terapia Cognitivo-Conductual , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto
3.
Clin Geriatr Med ; 16(3): 619-29, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10918650

RESUMEN

The utility of cardiac rehabilitation for elderly cardiac patients is controversial, and cost, logistic barriers, and encumbering comorbidities often seem disproportionate. Many clinicians view the emphasis of cardiac rehabilitation on behavior modification and risk-factor reduction as irrelevant for very old adults and consider pure exercise programs as appropriate alternatives. The strong rationale for cardiac rehabilitation and secondary prevention is elucidated, and available corroborating data are presented. The benefits of exercise prescription in cardiac rehabilitation and synchronized risk-factor reduction are pertinent to aging and age-related heart disease, including coronary heart disease and heart failure.


Asunto(s)
Enfermedad Coronaria/prevención & control , Enfermedad Coronaria/rehabilitación , Insuficiencia Cardíaca/prevención & control , Insuficiencia Cardíaca/rehabilitación , Factores de Edad , Anciano , Envejecimiento/patología , Envejecimiento/fisiología , Comorbilidad , Enfermedad Coronaria/etiología , Terapia por Ejercicio , Conductas Relacionadas con la Salud , Insuficiencia Cardíaca/etiología , Humanos , Estilo de Vida , Factores de Riesgo , Resultado del Tratamiento
4.
Am Heart J ; 139(1 Pt 1): 85-93, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10618567

RESUMEN

BACKGROUND: Increasing prevalence, use of health services, and number of deaths have made congestive heart failure (CHF) a new epidemic in the United States. Yet there are no adequate data to guide treatment of the more typical and complex cases of patients who are very old and frail. METHODS: Using the SAGE database, we studied the cases of 86,094 patients with CHF admitted to any of the 1492 long-term care facilities of 5 states from 1992 through 1996. We described their clinical and functional characteristics and their pharmacologic treatment to verify agreement with widely approved guidelines. We evaluated age- and sex-related differences, and we determined predictors of receiving an angiotensin-converting enzyme (ACE) inhibitor by developing a multiple logistic regression model. RESULTS: The mean age of the population was 84.9 +/- 8 years. Eighty percent of the patients 85 years of age or older were women. More than two thirds of patients underwent frequent hospitalizations related to CHF in the year preceding admission to a long-term care facility. Coronary heart disease and hypertension were the most common causes. Half of the patients received digoxin and 45% a diuretic, regardless of background cardiovascular comorbidities. Only 25% of patients had a prescription for ACE inhibitors. The presence of cardiovascular comorbidity, already being a recipient of a large number of medications, a previous hospitalization for CHF, and admission to the facility in recent years were associated with an increased likelihood of receiving an ACE inhibitor. The presence of severe physical limitation was inversely related to use of ACE inhibitors, as were a series of organizational factors related to the facilities. CONCLUSIONS: Patients in long-term care who have CHF little resemble to those enrolled in randomized trials. This circumstance may explain, at least in part, the divergence from pharmacologic management consensus guidelines. Yet the prescription of ACE inhibitors varies significantly across facilities and depends on organizational characteristics.


Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Digoxina/uso terapéutico , Diuréticos/uso terapéutico , Servicios de Salud para Ancianos , Insuficiencia Cardíaca/tratamiento farmacológico , Cuidados a Largo Plazo , Anciano , Anciano de 80 o más Años , Ensayos Clínicos como Asunto , Estudios Transversales , Quimioterapia Combinada , Femenino , Servicios de Salud para Ancianos/estadística & datos numéricos , Estado de Salud , Insuficiencia Cardíaca/rehabilitación , Humanos , Masculino , Guías de Práctica Clínica como Asunto , Estudios Retrospectivos
5.
J Adv Nurs ; 26(6): 1183-8, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9429969

RESUMEN

This paper presents a literature review in relation to the meaning of spirituality. It is proposed that meeting the spiritual needs of patients is a fundamental part of providing holistic nursing care, but that the assessment and meeting of those needs is impeded by inadequate definitions and conceptual frameworks. It should not be assumed that spirituality is either synonymous, or coterminous, with religion, and it is suggested that to adopt this restrictive view is unhelpful in the provision of individualized care. Reflection on the literature reveals that the self, others and 'God' provide the key elements within a definition of spirituality, and that other emerging themes namely meaning, hope, relatedness/connectedness, beliefs/belief systems and expressions of spirituality, can be articulated in the context of those three key elements. In particular, it is proposed that the nature of 'God' may take many forms and, essentially, is whatever an individual takes to be of highest value in his/her life. It is suggested that the themes emerging from the literature can be utilized as a framework to give practitioners and researchers a direction for future exploration of the concept of spirituality.


Asunto(s)
Enfermería Holística , Religión , Humanos
6.
Arch Biochem Biophys ; 303(1): 172-6, 1993 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-8489262

RESUMEN

Recently, it was demonstrated that 4-methylpyrazole was not only an inhibitor of alcohol dehydrogenase but also caused competitive inhibition of fatty acyl-CoA synthetase, the enzyme which activates fatty acids (B. U. Bradford, D. T. Forman, and R. G. Thurman, 1993, Mol. Pharmacol. 43, 115-119). Rates of catalase-dependent alcohol metabolism were decreased in alcohol dehydrogenase-negative (ADH-) deer mice because the H2O2 supply for catalase via peroxisomal fatty acid oxidation was inhibited due to substrate limitation. In light of these findings it became necessary to reevaluate the role of catalase and alcohol dehydrogenase in alcohol metabolism. In this study, methanol, a selective substrate for catalase in rodents, was compared with ethanol. Rates of ethanol and methanol metabolism were studied in vivo at blood alcohol levels ranging from 50 to 500 mg/dl. In the ADH- deer mouse, rates of methanol and ethanol metabolism increased when alcohol was elevated from 0 to 100 mg/dl and were maximal at values around 6-8 mmol/kg/h (half-maximal rates were observed at blood alcohol levels around 50 mg/dl). In the ADH+ deer mouse, rates of ethanol metabolism increased to values around 9 mmol/kg/h at 100 mg/dl and remained constant at blood levels up to 500 mg/dl. In contrast, rates of methanol metabolism increased to values of only 5 mmol/kg/h at levels of 100 mg/dl (the half-maximal rate was about 2.5 mmol/kg/h at 50 mg/dl) followed by a steady increase to 9 mmol/kg/h as the blood level was increased from 100 to 500 mg/dl (the half-maximal rate for this second component was around 6 mmol/kg/h at 300 mg/dl). Rates of methanol uptake were 50 +/- 4 nmol/min/mg protein in 10,000g pellets from ADH- deer mouse livers; however, methanol was not metabolized by isolated microsomes. The catalase inhibitor aminotriazole decreased ethanol and methanol metabolism 75% in ADH- deer mice. Further, olive oil, which is rich in oleate, increased methanol metabolism from 7 to 11.5 mmol/kg/h. This stimulation was blocked by fructose, which diminishes ATP and decreases H2O2 supply. In the ADH+ deer mouse, fructose (2 g/kg) stimulated ethanol metabolism as expected; however, inhibition of both ethanol and methanol metabolism was observed with higher doses of fructose (10 g/kg). Taken together, these data support the hypothesis that catalase is the predominant pathway for alcohol metabolism in the ADH- deer mouse. The contribution of catalase was about 50% in the ADH+ mutant at low doses of ethanol and approached 100% as the alcohol concentration was elevated.


Asunto(s)
Alcohol Deshidrogenasa/metabolismo , Catalasa/metabolismo , Etanol/metabolismo , Metanol/metabolismo , Amitrol (Herbicida)/farmacología , Animales , Catalasa/antagonistas & inhibidores , Fructosa/farmacología , Aceite de Oliva , Oxidación-Reducción , Peromyscus , Aceites de Plantas/farmacología
7.
Artículo en Inglés | MEDLINE | ID: mdl-1306092

RESUMEN

Stomach cancer mortality data were compared with dietary and biochemical data from 65 Chinese counties to provide clues to reasons for the marked geographic variation of stomach cancer mortality rates in China. Sex-specific correlation and multivariate regression analyses showed significant positive associations with consumption of salted vegetables and eggs, prevalence of antibodies to Helicobacter pylori, and levels of plasma albumin; and significant negative associations with intake of green vegetables and levels of plasma selenium and beta-carotene. Limitations of ecological data preclude causal inferences, but these findings suggest factors that may contribute to making stomach cancer the leading cause of cancer death in China and other countries.


Asunto(s)
Neoplasias Gástricas/mortalidad , Adulto , Anticuerpos Antibacterianos/sangre , Carotenoides/sangre , China/epidemiología , Estudios Transversales , Encuestas sobre Dietas , Huevos/efectos adversos , Femenino , Infecciones por Helicobacter/sangre , Infecciones por Helicobacter/complicaciones , Infecciones por Helicobacter/epidemiología , Helicobacter pylori , Humanos , Masculino , Persona de Mediana Edad , Características de la Residencia , Factores de Riesgo , Selenio/sangre , Albúmina Sérica/análisis , Sodio en la Dieta/efectos adversos , Neoplasias Gástricas/sangre , Neoplasias Gástricas/etiología , Verduras , beta Caroteno
8.
Brain Res ; 446(1): 26-36, 1988 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-3370484

RESUMEN

Particulate organelles in isolated axons from the walking legs of the lobster were detected with differential interference contrast optics and video microscopic techniques. The motion of the organelles was studied in normal axons, in axons whose surface membrane was rendered permeable with saponin, and in axoplasm extruded from the axons. In normal axons at 20-22 degrees C, organelles moved more rapidly in the anterograde direction than in the retrograde direction (respective mean velocities 1.73 micron/s and 0.63 micron/s). The instantaneous velocities of both sets of organelles were variable: those of the anterograde organelles varied less than those of retrograde organelles. The variation in instantaneous velocity was patterned; all organelles studied had velocities that fluctuated slowly with a major frequency at about 0.1 Hz. Some organelles oscillated about a fixed position at a similar major frequency. In axons with a permeabilized surface membrane there was no organelle motion unless adenosine 5'-triphosphate (ATP) was present in the bathing medium. Organelle motion reactivated with ATP was patterned in a way similar to that in normal intact axons. In extruded axoplasm in the presence of ATP, organelles moved along transport filaments that were assumed to be microtubules. Movement of organelles from one transport filament to another was not accompanied by changes in motion that could explain the normal fluctuation in velocity. The evidence indicates that the variable, or oscillatory, character of organelle motion in lobster axons is caused by an active component of the mechanisms of axonal transport.


Asunto(s)
Axones/fisiología , Organoides/fisiología , Animales , Axones/ultraestructura , Membrana Celular/fisiología , Permeabilidad de la Membrana Celular , Técnicas In Vitro , Nephropidae , Organoides/ultraestructura , Saponinas
9.
Brain Res ; 412(1): 96-106, 1987 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-3607465

RESUMEN

Mitochondria in isolated motor axons from the walking legs of lobster were observed with differential interference contrast optics and video microscopic techniques. Movements of the mitochondria were analyzed in time-lapse videotape records. The mean velocity of transport in the retrograde direction (1.33 +/- 0.64 micron/s) was greater than the mean velocity of transport in the anterograde direction (0.72 +/- 0.26 micron/s). The mean lengths of the mitochondria moving in the retrograde and anterograde directions were only slightly different (6.9 microns and 5.5 microns, respectively). No correlation was found between mitochondrial length and average velocity or reciprocal velocity. The instantaneous velocities of mitochondria were distributed over a range of approximately 3 micron/s; both the anterograde and retrograde distributions contained a small proportion of values whose sign was opposite to the modal value. The variation in instantaneous velocity took place at frequencies close to 0.1 Hz. Some mitochondria displayed longitudinally oriented oscillatory movements of a similar low frequency. While the movement of most mitochondria was parallel to the axis of the axon, transverse deviations and complex circular paths were sometimes observed. Some mitochondria reversed their orientation and continued in the same direction, so that the end which had been the leading end became the trailing end. Many mitochondria immediately beneath the plasma membrane were stationary and adhered strongly to the plasma membrane when the axoplasmic structure was disrupted. In electron micrographs, fine strands connected peripheral mitochondria and the plasma membrane. These strands may anchor the stationary mitochondria to the plasma membrane.


Asunto(s)
Axones/ultraestructura , Mitocondrias Musculares/ultraestructura , Organoides/fisiología , Animales , Membrana Celular/ultraestructura , Microscopía Electrónica , Mitocondrias Musculares/fisiología , Movimiento , Nephropidae
10.
J Neurocytol ; 16(1): 69-75, 1987 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2438388

RESUMEN

Polarity orientations of microtubules in periaxolemmal and internal regions of squid and lobster axons were determined in order to test the hypothesis that regional differences in particle transport are produced by differentially distributed microtubule subclasses. Over 95% of the microtubules in all regions of the axons investigated were oriented with plus ends located distally, pointing away from axonal somata, and there were no significant differences in orientation ratios in periaxolemmal and internal axoplasm. In axonal sheath glial cells of lobsters, microtubules were found to be oriented parallel to axonal microtubules and to have approximately equally mixed polarities. The results for axonal microtubules did not support the possibility of subclasses of axonal microtubules.


Asunto(s)
Axones/ultraestructura , Decapodiformes/anatomía & histología , Microtúbulos/ultraestructura , Nephropidae/anatomía & histología , Animales , Transporte Axonal , Microscopía Electrónica , Neuroglía/ultraestructura , Especificidad de la Especie
11.
IARC Sci Publ ; (84): 518-23, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3679434

RESUMEN

Urinary excretion of N-nitrosoproline (NPRO) following ingestion of a high-nitrate salad meal, without then with an oral dose of 500 mg L-proline, was investigated in 16 healthy volunteers. The mean excretion rate following consumption of the high-nitrate meal alone was significantly lower than that measured after ingestion of the salad plus proline. Supplementation of the same meal (plus proline) with vitamin C from dietary sources resulted in a significant decrease in mean urinary NPRO levels in healthy subjects. The nitrosation-inhibiting effect of vitamin C was not affected by an increase in the fat content of the meal. Supplementation of the high-nitrate salad with alcohol or coffee did not affect subsequent urinary NPRO levels. No significant difference was observed in the urinary NPRO concentrations of smokers and nonsmokers after ingestion of high-nitrate salad (with or without vitamin C) plus proline.


Asunto(s)
Nitratos/metabolismo , Nitrosaminas/metabolismo , Neoplasias Gástricas/etiología , Ácido Ascórbico/metabolismo , Dieta , Humanos , Nitratos/administración & dosificación , Nitritos/metabolismo , Nitrosaminas/orina , Prolina/metabolismo , Saliva/metabolismo
12.
Cell Motil ; 4(2): 121-8, 1984.
Artículo en Inglés | MEDLINE | ID: mdl-6203649

RESUMEN

In a permeabilized axon model, exogenous ATP can reactivate intraaxonal saltatory organelle movements (microscopically visible manifestations of fast axonal transport). We have studied the dependence of the reactivated movements on the ATP concentration and have also examined the nucleotide specificity of the reactivation. Organelle transport was visualized in isolated lobster giant motor axons using Nomarski optics and video microscopy. The axons were permeabilized with saponin, and movement was reactivated with ATP or other nucleotides. Some slight movement was seen with ATP concentrations as low as 10 microM. The velocity and frequency of the reactivated transport increased with increasing ATP concentrations up to about 5 mM. Movement was also reactivated by deoxyadenosine triphosphate, but not by AMP-PNP (a nonhydrolyzable ATP analogue), ADP, or AMP. Although other nucleotides (CTP, GTP, UTP, ITP) could reactivate transport, movement equivalent to that produced by 0.1 mM ATP was only seen with tenfold or greater concentrations of the other nucleotides. This pattern of specificity is consistent with the hypothesis that a dynein-like ATPase, rather than a myosin, is involved in fast axonal transport.


Asunto(s)
Adenosina Trifosfato/fisiología , Transporte Axonal , Axones/fisiología , Organoides/fisiología , Animales , Axones/metabolismo , Axones/ultraestructura , Dineínas/fisiología , Movimiento , Nephropidae , Nucleótidos/fisiología
13.
Brain Res ; 272(1): 194-7, 1983 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-6193834

RESUMEN

Retrograde transport of microscopically visible organelles in isolated lobster axons was selectively inhibited by erythro-9-[3-(2-hydroxynonyl)]adenine (EHNA), with little or no effect on anterograde transport. The retrograde velocity was reduced both in living axons and in permeabilized axons in which movement was reactivated with exogenous ATP. This is the first report of an agent that selectively inhibits axonal transport in one direction.


Asunto(s)
Adenina/análogos & derivados , Transporte Axonal/efectos de los fármacos , Adenina/farmacología , Adenosina Trifosfato/farmacología , Animales , Nephropidae , Organoides/efectos de los fármacos
14.
J Neurosci ; 3(6): 1279-88, 1983 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-6189982

RESUMEN

We have developed a method for permeabilizing axons and reactivating the fast transport of microscopically visible organelles. Saltatory movements of organelles in motor axons isolated from lobster walking legs were observed using Nomarski optics and time-lapse video microscopy. In the center of the axon most of the particles and mitochondria moved in the retrograde direction, but immediately below the axolemma the majority moved in the anterograde direction. When axons were permeabilized with 0.02% saponin in an adenosine 5'-triphosphate (ATP)-free "internal" medium, all organelle movement ceased. Saltatory movements resembling those in intact axons immediately reappeared upon the addition of MgATP. Very slight movement could be detected with ATP concentrations as low as 10 microM, and movement appeared to be maximal with 1 to 5 mM ATP. Vanadate, which does not affect axonal transport in intact axons, inhibited the reactivated organelle movements in permeabilized axons. Movement was rapidly and reversibly inhibited by 50 to 100 microM sodium orthovanadate. The effects of vanadate, including the time course of inhibition, its reversibility, and its concentration dependence, are consistent with the hypothesis that a dyneinlike like molecule may play a role in the mechanism of fast axonal transport.


Asunto(s)
Transporte Axonal/efectos de los fármacos , Vanadio/farmacología , Adenosina Trifosfato/fisiología , Animales , Axones/efectos de los fármacos , Mitocondrias/metabolismo , Nephropidae , Organoides/metabolismo , Saponinas , Vanadatos
15.
Ann Clin Lab Sci ; 10(4): 345-50, 1980.
Artículo en Inglés | MEDLINE | ID: mdl-7004332

RESUMEN

Determination of serum ferritin is an important means of assessing body iron stores. Trace amounts of ferritin normally present in serum are detectable by sensitive radioimmunoassay techniques or an enzyme immunoassay procedure. Ferritin normally accounts for no more than a very small fraction of the total iron in serum, but generally maintains a stable concentration that is proportional to the much larger pool of storage iron in tissues. The serum ferritin assay, in contrast to other measurements of iron status such as hemoglobin, serum iron and iron-binding capacity, can distinguish differences in iron stores within the physiological range. In iron deficiency anemia, the concentration is below 10 ng per ml. Increased concentrations (above 200 ng per ml) are found in conditions with increased iron stores. The information it provides is similar to that obtained from bone-marrow aspirates stained for iron. In contrast to the percent transferrin-saturation and concentration of erythrocyte protoporphyrin, ferritin concentrations become abnormal before exhaustion of mobilizable iron stores and before the onset of anemia. Serum ferritin also provides a practical means of assessing new programs of iron supplementation, since it reflects various degrees of iron deficiency and overload.


Asunto(s)
Ferritinas/sangre , Anemia Hipocrómica/diagnóstico , Examen de la Médula Ósea , Femenino , Humanos , Técnicas para Inmunoenzimas , Hierro/metabolismo , Masculino , Radioinmunoensayo , Ensayo de Unión Radioligante
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