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3.
Int Nurs Rev ; 58(3): 379-85, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21848787

RESUMO

BACKGROUND: The present study considers the production of knowledge and the interactions in the environment of research and their relationships in the system of caring in nursing and health. AIM: To elaborate a theoretical model of the organization of the practices used for caring, based on the experiences made by the research groups of administration and management in nursing, in Brazil. METHODS: The study is based on grounded theory. Twelve leaders of research groups, working as professors in public universities in the south and the south-east of Brazil, distributed in sample groups, were interviewed. FINDINGS: The core phenomenon 'research groups of administration and management in nursing: arrangements and interactions in the system of caring in nursing' was derived from the categories: conceptual bases and contexts of the research groups; experiencing interactions in the research groups; functionality of the research groups; and outputs of the research groups. The research groups are integrated in the system of caring in nursing. CONCLUSIONS: The activities of the Brazilian administration and management in nursing research groups are process oriented and in a process of constant renovation, socially relevant, operate in a complex scenario and contribute to the advancement of the organizations of the system of caring in nursing through strengthening the connection among academia, service and community.


Assuntos
Empatia , Pesquisa em Administração de Enfermagem/organização & administração , Pesquisa Translacional Biomédica , Brasil , Humanos , Pesquisa em Administração de Enfermagem/métodos
4.
Eur J Neurol ; 18(9): 1122-31, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21362108

RESUMO

BACKGROUND: Spasticity is a disabling complication of multiple sclerosis, affecting many patients with the condition. We report the first Phase 3 placebo-controlled study of an oral antispasticity agent to use an enriched study design. METHODS: A 19-week follow-up, multicentre, double-blind, randomized, placebo-controlled, parallel-group study in subjects with multiple sclerosis spasticity not fully relieved with current antispasticity therapy. Subjects were treated with nabiximols, as add-on therapy, in a single-blind manner for 4weeks, after which those achieving an improvement in spasticity of ≥20% progressed to a 12-week randomized, placebo-controlled phase. RESULTS: Of the 572 subjects enrolled, 272 achieved a ≥20% improvement after 4weeks of single-blind treatment, and 241 were randomized. The primary end-point was the difference between treatments in the mean spasticity Numeric Rating Scale (NRS) in the randomized, controlled phase of the study. Intention-to-treat (ITT) analysis showed a highly significant difference in favour of nabiximols (P=0.0002). Secondary end-points of responder analysis, Spasm Frequency Score, Sleep Disturbance NRS Patient, Carer and Clinician Global Impression of Change were all significant in favour of nabiximols. CONCLUSIONS: The enriched study design provides a method of determining the efficacy and safety of nabiximols in a way that more closely reflects proposed clinical practice, by limiting exposure to those patients who are likely to benefit from it. Hence, the difference between active and placebo should be a reflection of efficacy and safety in the population intended for treatment.


Assuntos
Esclerose Múltipla/tratamento farmacológico , Espasticidade Muscular/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Adulto , Idoso , Canabidiol , Método Duplo-Cego , Dronabinol , Combinação de Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Espasticidade Muscular/etiologia
5.
Opt Express ; 17(2): 544-51, 2009 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-19158866

RESUMO

Thin metal films show a residual transmission for light in the visible and UV spectral range. This transmission can be strongly reduced by an appropriate sub-wavelength patterning of the metal film. Our investigation is focused on metal films with a thickness much below 100nm, where the transmission response is dominated by the individual posts acting like antennas and cannot be attributed to the excitation of surface plasmons. The almost complete suppression of transmission for ultra-thin metal films depends mainly on the absorber width, but not on the pitch of the pattern. The effect is robust with respect to imperfections of the geometry or larger features imprinted into the sub-wavelength pattern.

6.
Psychopathology ; 35(5): 272-9, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12457018

RESUMO

The impact of auditory command hallucinations on the behaviour of schizophrenic patients sometimes appears to be unpredictable. In order to tackle this problem, the psychopathological characteristics of command hallucinations in 31 schizophrenic patients were assessed using a 24-item questionnaire. Using binary data and relative risk analysis methods, predictors were determined for obeying or resisting command hallucinations. Characteristics of voices and the attitude toward the voices appear equally important for prediction. A set of three psychopathological characteristics comprising a voice known to the patient, emotional involvement during the hallucinations, and seeing the voice as real provides significant predictivity of behaviour following command hallucinations. These results are interesting for clinical and forensic psychiatrists.


Assuntos
Tomada de Decisões , Alucinações/epidemiologia , Alucinações/psicologia , Adolescente , Adulto , Análise por Conglomerados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
7.
Fortschr Neurol Psychiatr ; 69(5): 203-10, 2001 May.
Artigo em Alemão | MEDLINE | ID: mdl-11417259

RESUMO

Command hallucinations are a subtype of auditory verbal hallucinations in schizophrenia. More likely than any other schizophrenic symptom, they may have an impact on the individual's behavior. In the forensic literature, aspects of dangerous actions induced by psychotic motivation have been discussed. From the psychiatric point of view, the main problem is the unpredictability of behavioral consequences. The present study examines psychopathological details of command hallucinations in 31 hospitalized schizophrenic patients, 10 females and 21 males, using a questionnaire including 24 items. The predictive accuracy of a distinct set of signs was rated concerning compliance vs. resistance of hallucinated commands. The predictors are: identifying the hallucinated voice, being affected by emotions after hallucinations, and misregarding the voice as being real. In the presence of these conditions, behavioral consequences are predicted by a value which was 6.7 times higher than that without any information about predictors. In the absence of these conditions, resistance of command voices is predicted by a value of 7.


Assuntos
Alucinações/psicologia , Psicologia do Esquizofrênico , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica
8.
Rev Gaucha Enferm ; 21(2): 19-36, 2000 Jul.
Artigo em Português | MEDLINE | ID: mdl-11998465

RESUMO

The article approaches some aspects considered relevant to rethink relations on the care offered by health services, especially, hospital organizations. It presents some reflection upon the possibilities of constructing human civility, centered on solidarity relations and on the exercise of citizenship, on an ethical condition of a dignified and healthier life. Mutual comprehension between human beings is vital to restore life, nature and conviviality values.


Assuntos
Relações Interprofissionais , Cuidados de Enfermagem , Ética em Enfermagem , Humanos
9.
Behav Neurosci ; 112(5): 1048-61, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9829783

RESUMO

Twenty-six split-brain rhesus monkeys learned and remembered 8 go/no-go discriminations of monkey faces significantly better with the right hemisphere than with the left. Four discriminations required differentiating individual identity with expression held constant, and 4 required discriminating facial expression with identity held constant. There was no significant difference in the degree of laterality shown for these 2 types of problems. Female monkeys were more lateralized for learning to discriminate faces than were males. This sex difference in laterality was significant for learning but not for memory. Laterality for the facial discriminations was not significantly related to handedness of the monkeys. Overall, rhesus monkeys, like humans, show a right-hemispheric superiority for facial processing.


Assuntos
Comportamento Animal/fisiologia , Encéfalo/fisiologia , Aprendizagem por Discriminação/fisiologia , Expressão Facial , Lateralidade Funcional , Análise de Variância , Animais , Encéfalo/cirurgia , Feminino , Macaca mulatta , Masculino , Memória/fisiologia , Caracteres Sexuais
10.
J Struct Biol ; 121(1): 19-29, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9573617

RESUMO

In 26S proteasomes, "19S cap complexes" associate with either one or both ends of the barrel-shaped 20S core complex. These regulatory complexes which comprise about 20 different subunits, including 6 ATPases of the AAA family, are thought to recognize ubiquitinated substrate proteins, to dissociate and unfold them before threading them into the 20S core where they are degraded. Here, we examine the structure of 26S proteasomes from Drosophila embryos and Xenopus oocytes by electron microscopy. Image analysis reveals a rather flexible linkage between the 19S caps and the 20S core, with a peculiar wagging-type movement of the caps relative to the core. At this stage of the analysis, it is not clear whether this movement is relevant in terms of function. Three-dimensional reconstructions, taking this into account, provide first insights into the remarkably complex structure of the 19S caps and allows us to put forward a composite model of the entire 26S complex.


Assuntos
Microscopia Eletrônica/métodos , Peptídeo Hidrolases/química , Peptídeo Hidrolases/ultraestrutura , Complexo de Endopeptidases do Proteassoma , Animais , Drosophila melanogaster/enzimologia , Feminino , Processamento de Imagem Assistida por Computador , Substâncias Macromoleculares , Modelos Moleculares , Oócitos/enzimologia , Conformação Proteica , Xenopus
11.
Thyroid ; 7(4): 633-40, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9292955

RESUMO

Transforming growth factor beta 1 (TGF beta 1) is an autocrine growth factor for thyrocytes and is supposed to be the mediator of iodine-induced growth inhibition of thyroid epithelial cells, but this is still controversial. We further investigated this hypothesis using intact porcine thyroid follicles ex vivo in a three-dimensional culture system. In this culture system it has been shown previously that both iodide as well as delta-iodolactone, the putative iodocompound mediating thyroid cell proliferation, inhibit growth of these follicles. We measured the amount of TGF beta 1 mRNA expression in these follicles after treatment either with thyrotropin (TSH), epidermal growth factor (EGF), or transforming growth factor alpha (TGF alpha) for growth stimulation or with inorganic iodine or delta-iodolactone in concentrations known to inhibit growth. TGF beta 1-mRNA was detected by Northern blot analysis. The known major transcript of 2.5 kb was detected in a steady state level up to 48 hours in untreated thyroid follicles. EGF and TGF alpha (5 ng/mL each) enhanced TGF beta 1 mRNA about threefold within 4 and 8 hours. This increase of TGF beta 1 mRNA was slightly decreased by simultaneous incubation with delta-iodolactone (1 microM) or iodide (40 microM KI). In contrast, both TSH (1 mU/mL) and forskolin (16 microM) decreased TGF beta 1 mRNA expression to about 70%, and this effect was abolished when follicles were pretreated with iodide (40 microM KI) in a concentration known to inhibit TSH action on cyclic adenosine monophosphate (cAMP) formation and proliferation. Iodide or delta-iodolactone alone had no significant effect on basal TGF beta 1 mRNA expression. We conclude that the growth inhibitory effect of iodide as well as of delta-iodolactone is not mediated through TGF beta 1 in intact porcine thyroid follicles ex vivo. The stimulatory effect of EGF and TGF alpha on TGF beta 1 expression might be related to extracellular matrix modulation during proliferation.


Assuntos
Ácidos Araquidônicos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Substâncias de Crescimento/farmacologia , Glândula Tireoide/metabolismo , Fator de Crescimento Transformador beta/genética , Animais , Células Cultivadas , Colforsina/farmacologia , Fator de Crescimento Epidérmico/farmacologia , Iodeto de Potássio/farmacologia , RNA Mensageiro/metabolismo , Suínos , Tireotropina/farmacologia
12.
Eur J Immunol ; 27(7): 1671-9, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9247576

RESUMO

Cell surface components of pathogens, such as lipopolysaccharide (LPS), are an important signal for receptor-mediated activation of immune cells. Here we demonstrate that DNA of gram-positive and gram-negative bacteria or certain synthetic oligonucleotides displaying unmethylated CpG-motifs can trigger macrophages in vitro to induce nuclear translocation of nuclear factor-kappa B, accumulate tumor necrosis factor (TNF)-alpha mRNA and release large amounts of TNF-alpha. In vivo these events culminate in acute cytokine-release syndrome which includes systemic but transient accumulation of TNF-alpha. D-Galactosamine (DGalN)-sensitized mice succumb to lethal toxic shock due to macrophage-derived TNF-alpha resulting in fulminant apoptosis of liver cells. LPS and a specific oligonucleotide synergized in vivo as measured by TNF-alpha-release, suggesting that macrophages integrate the respective signals. The ability of macrophages to discriminate and to respond to bacterial DNA with acute release of pro-inflammatory cytokines may point out an important and as yet unappreciated sensing mechanism for foreign DNA.


Assuntos
DNA Bacteriano/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/microbiologia , Choque Séptico/imunologia , Choque Séptico/microbiologia , Fator de Necrose Tumoral alfa/fisiologia , Animais , Apoptose/genética , Apoptose/imunologia , Composição de Bases/imunologia , DNA Bacteriano/administração & dosagem , DNA Bacteriano/farmacologia , Sinergismo Farmacológico , Galactosamina/imunologia , Injeções Intraperitoneais , Lipopolissacarídeos/administração & dosagem , Fígado/imunologia , Fígado/metabolismo , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/genética , Macrófagos Peritoneais/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos SCID , Oligodesoxirribonucleotídeos/administração & dosagem , Oligodesoxirribonucleotídeos/farmacologia , Choque Séptico/genética , Fator de Necrose Tumoral alfa/biossíntese
13.
Ann Hematol ; 75(1-2): 33-9, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9322681

RESUMO

In order to determine the dynamics of hematopoietic cell turnover, proliferative activity and incidence of apoptosis (programmed cell death) were evaluated in bone marrow trephine biopsies. Selection of patients (20 in each group) included in addition to a control group, idiopathic thrombocytopenia (ITP), reactive thrombocytosis (TH), secondary polycythemia-smokers' polyglobuly (PG), primary (essential-hemorrhagic) thrombocythemia (PTH), polycythemia vera (PV), and finally acute myeloid leukemia (AML). Apoptosis was demonstrated by the in situ end-labeling technique (ISEL) and proliferative activity by applying the monoclonal antibody PC10 raised against proliferating cell nuclear antigen (PCNA). To assess dynamic features of hematopoiesis, an index was calculated consisting of the ratio between PCNA-positive nuclei and the apoptotic cell fraction. This factor was termed the hematopoietic turnover index (HTI). Morphometric analysis revealed that the HTI was significantly increased in AML and PV. According to cell culture studies both disorders are characterized by either a prevalent proliferation of the myeloid or erythroid cell mass. On the other hand, PG, PTH, and TH showed no relevant enhancement of this index in comparison to the control specimen. In vitro experiment results are in keeping with the finding that PG and PTH are not associated with a significant expansion of the erythroid lineage (CFU-E). Similar to ITP and TH, in PTH megakaryocyte proliferation (CFU-MEG) is the predominant feature of cell turnover. Differences between PTH and TH are in line with the reduced in vitro formation of CFU-MEG in the latter disorder. In conclusion, our in situ study on turnover rates of the bone marrow in various neoplastic and reactive lesions extends previous experimental data on hematopoietic cell kinetics.


Assuntos
Doenças da Medula Óssea/fisiopatologia , Hematopoese , Doença Aguda , Antígenos de Neoplasias/análise , Apoptose , Neoplasias da Medula Óssea/fisiopatologia , Humanos , Leucemia Mieloide/fisiopatologia , Policitemia/fisiopatologia , Antígeno Nuclear de Célula em Proliferação/análise , Trombocitopenia/fisiopatologia , Trombocitose/fisiopatologia
14.
Eur J Immunol ; 27(4): 825-33, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9130631

RESUMO

Endotoxin (lipopolysaccharide; LPS) and superantigens (exotoxins) have been identified as potent inducers of lethal shock. While endotoxin primarily interacts with CD14 receptors on macrophages, superantigens like the staphylococcal enterotoxin B (SEB) preferentially activate T cells. Both cell types are triggered to release pro-inflammatory cytokines that in turn induce lethal shock. We analyzed whether endotoxin and superantigen interact during the induction phase of lethal shock. We report that LPS and SEB operate synergistically. Lethal doses of both inducers were reduced 100-fold when given in combination. The induced serum levels of tumor necrosis factor, interleukin-6, and interferon-gamma (IFN-gamma) were elevated and remained high for a prolonged period. Moreover, synergistic action of LPS and SEB induced lethal toxic shock even without presensitization of mice with D-galactosamine (D-GalN). Opposed to D-GalN-pretreated mice, mice injected with LPS and SEB showed less liver damage, but rather apoptosis of epithelial cells in the bowel. Cyclosporin A and treatment with anti-IFN-gamma monoclonal antibody blocked the synergistic action of LPS and SEB, indicating that T cell-derived IFN-gamma is the mediator of the observed synergism. Concomitant injection of LPS and SEB had no influence on SEB-induced T cell deletion and anergy induction. Since Gram-positive and Gram-negative bacteria can be recovered from septic blood samples, the synergistic action of endotoxin and superantigens might be relevant during lethal septicemia.


Assuntos
Enterotoxinas/farmacologia , Lipopolissacarídeos/farmacologia , Choque Séptico/etiologia , Staphylococcus aureus/imunologia , Superantígenos/farmacologia , Animais , Anticorpos Bloqueadores/farmacologia , Anticorpos Monoclonais/farmacologia , Anergia Clonal , Deleção Clonal , Ciclosporina/farmacologia , Citocinas/biossíntese , Citocinas/sangue , Sinergismo Farmacológico , Enterotoxinas/administração & dosagem , Enterotoxinas/antagonistas & inibidores , Feminino , Galactosamina/administração & dosagem , Galactosamina/análogos & derivados , Injeções Intravenosas , Interferon gama/imunologia , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Choque Séptico/patologia , Superantígenos/administração & dosagem , Superantígenos/imunologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
15.
Rev Lat Am Enfermagem ; 4(3): 89-98, 1996 Dec.
Artigo em Português | MEDLINE | ID: mdl-9070796

RESUMO

The nursing department is a complex organization, or a social system, made up of two or more groups interconnected through a complex net of social relations, common values and goals, used as the context for nursing interventions. The complex organization embodies type, subsystems, limitations, philosophy, life styles and process of adaptation to the environment, integration of subsystems, decision making, information processing, communications, coalition-formation and commitment. Theoretical interchange proposal to achieve full quality parameters is based on the seven stages of Lippit's exchange theory.


Assuntos
Serviço Hospitalar de Enfermagem/organização & administração , Gestão da Qualidade Total/organização & administração , Tomada de Decisões Gerenciais , Humanos , Relações Interprofissionais , Teoria de Enfermagem , Inovação Organizacional
16.
MD Comput ; 13(2): 173-9, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8684281

RESUMO

Recognizing that machines in the practice of medicine are here to stay, physicians have the obligation to learn as much of their advantages and limitations as they can comprehend. The machine described here merely correlates symptoms set down by the patient and draws conclusions on the basis of what it has "learned" from physicians. Hence it makes the same errors as the human brain which "taught" it plus others that are inherent in its inability to initiate the thinking process. One reviewer of the paper presented below asked this important question, "What is the character of the error when a diagnosis is made which is not correct? If a patient with flat feet is simply not so diagnosed, this is one type of error, but if the machine reads, ¿respiratory tuberculosis inactive,' it's another." This and many other questions properly may arise. At the same time, the device is an extremely ingenious one and does eliminate the factors of emotional bias and fatigue, which may confuse the issue when a physician tries to analyze the complex of subjective complaints which the patient serves up to him. Whether the machine described here will have a place in the internists' armamentarium cannot be determined until more of them know about it.


Assuntos
Diagnóstico por Computador/história , Computadores/história , Feminino , História do Século XX , Humanos , Masculino
17.
Appl Environ Microbiol ; 61(12): 4334-42, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16535186

RESUMO

Corynebacterium glutamicum can be triggered to excrete glutamate by the addition of local anesthetics, particularly tetracaine. Glutamate efflux is a carrier-mediated process and not due to unspecific membrane permeabilization. The concentration of local anesthetics triggering optimum excretion depended on the type of anesthetic and varied, ranging from 0.1 (chlorpromazine), 1.3 (tetracaine), and 2.6 mM (butacaine) to 15 mM (benzocaine), in close resemblance to the order of efficiency in anesthetic effect. The onset of glutamate excretion was not correlated to a change in the viscosity or fluidity of the membrane, as measured by electron spin resonance spectroscopy, nor was it related to an action of the anesthetic as an uncoupler. Tetracaine-triggered glutamate excretion was sensitive to changes in the transmembrane osmotic gradient, although an osmotic gradient alone could not trigger glutamate excretion. Tetracaine-triggered glutamate efflux was inhibited by an external rise in osmolality and stimulated by a corresponding decrease. The effects of osmotic gradients and the addition of local anesthetics on glutamate excretion were mutually exchangeable, indicating similar modes of action. We suggest that this common principle is a change in the membrane strain. C. glutamicum cells which excrete glutamate without manipulation of the membrane, e.g., biotin-limited cells or glutamate production mutants, were not stimulated by the addition of tetracaine.

18.
Am J Physiol ; 266(1 Pt 1): C95-103, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8304434

RESUMO

Ouabain-resistant K efflux and Rb influx in Cl and NO3 media were studied in volume-clamped low-K (LK) sheep red blood cells (SRBC) with normal and experimentally reduced cytoplasmic Mg (Mgi) levels as function of pH and at 37 degrees C. Sucrose was added to solutions with constant ionic strength and variable pH to maintain normal cell volume. Cl-dependent ouabain-resistant K(Rb) fluxes (K-Cl cotransport) at unity relative cell volume exhibited a maximum at pH approximately 7 in normal-Mgi LK cells consistent with the apparent acid pH activation reported for human erythrocytes. However, in LK SRBC with Mgi lowered by A-23187 and an external Mg chelator, K(Rb)-Cl cotransport was reversibly activated as the pH was raised from 6.5 to 9. The alkaline pH effect on Cl-dependent Rb influx in low-Mgi LK SRBC was due to a 10-fold rise in the maximum velocity values without a major change in the Km values. The pH dependence of the experimental flux reversal point, i.e., the extracellular Rb concentration at which no net K-Cl cotransport occurs, approximately paralleled that of the flux reversal point predicted from the ratio of the ion products, in both control and low-Mgi LK cells, albeit with a small displacement to higher extracellular Rb concentration at all pH values. The kinetic data can be explained by a general minimum three-state equilibrium in which deprotonation recruits transporters from a resting R state into the active A state modified by Mgi to an inactive I state.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Equilíbrio Ácido-Base , Proteínas de Transporte/metabolismo , Eritrócitos/citologia , Eritrócitos/metabolismo , Concentração de Íons de Hidrogênio , Magnésio/fisiologia , Potássio/sangue , Simportadores , Animais , Cloretos/farmacologia , Meios de Cultura , Cinética , Magnésio/metabolismo , Nitratos/farmacologia , Ovinos/sangue , Termodinâmica , Cotransportadores de K e Cl-
19.
Ukr Biokhim Zh (1978) ; 65(5): 3-20, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8160294

RESUMO

Effect of low ionic force on the passive transport of univalent cations through the erythrocyte membranes is considered. It is postulated that this effect is complex and cannot be explained on the basis of electrodiffusion. Data are presented on the already known transport pathways in the erythrocyte membranes for univalent cations. Characteristics of residual cation transport (the "leak" flux) through the erythrocyte membranes also affected by the low ionic force are presented.


Assuntos
Cátions Monovalentes/sangue , Membrana Eritrocítica/metabolismo , Animais , Transporte Biológico/fisiologia , Cálcio/sangue , Humanos , Lítio/sangue , Potássio/sangue , Sódio/sangue , Especificidade da Espécie
20.
Gen Physiol Biophys ; 11(3): 287-99, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1330813

RESUMO

The Rb+(K+) efflux of erythrocytes from six mammalian species was investigated in solutions of physiological and low ionic strength. A species dependent increase of the Rb+(K+) efflux in low ionic strength solution could be observed. The rate constant of Rb+(K+) efflux of erythrocytes in physiological ionic strength solution correlates with the content of arachidonic acid of the membrane phospholipids. The same relation was observed in solution of low ionic strength with the exception of human erythrocytes. In addition, an age-dependent correlation of the rate constant of Rb+(K+) efflux from calf erythrocytes in low ionic strength solution with the content of arachidonic acid of the membrane phospholipids was found. The Rb+(K+) efflux of human erythrocytes, which is enhanced in low ionic strength solution, decreases with the decreasing temperature. The temperature-dependent ESR order parameter of a fatty acid spin label for human and cow erythrocytes in solution of physiological and low ionic strength media suggested that the effect of low ionic strength on Rb+(K+) efflux is not solely based on a change of membrane fluidity. The results are interpreted as being due to a specific influence of membrane phospholipids on the Rb+(K+) efflux.


Assuntos
Eritrócitos/metabolismo , Lipídeos de Membrana/sangue , Fosfolipídeos/sangue , Potássio/sangue , Envelhecimento/sangue , Animais , Ácidos Araquidônicos/sangue , Transporte Biológico , Bovinos , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Técnicas In Vitro , Mamíferos , Fluidez de Membrana , Concentração Osmolar , Rubídio/sangue , Especificidade da Espécie , Termodinâmica
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