RESUMO
Granulomatosis with Polyangiitis (GPA), or Wegener's Granulomatosis, is an immunologically mediated systemic vasculitis of small and medium vessels, which commonly compromises the upper airway, lungs, and kidneys and is rarely associated with cardiac manifestations. Compromise of the cardiac conduction system is rare, and isolated cases of different degrees of atrioventricular block (AVB) have been described. We report a case of a 49-year-old male patient previously diagnosed with GPA 3 years ago, who presented to the emergency department with dyspnea, clinical signs of low output, bradycardia of 30/min, advanced second-degree AVB and complete left bundle branch block (LBBB) on the ECG. A literature review is presented, and we discuss the causes, evolution, and management of this GPA complication.
Assuntos
Bloqueio Atrioventricular , Eletrocardiografia , Granulomatose com Poliangiite , Humanos , Granulomatose com Poliangiite/complicações , Masculino , Pessoa de Meia-Idade , Bloqueio Atrioventricular/etiologiaRESUMO
Brillouin spectroscopy emerges as a promising non-invasive tool for nanoscale imaging and sensing. One-dimensional semiconductor superlattice structures are eminently used for selectively enhancing the generation or detection of phonons at few GHz. While commercially available Brillouin spectrometers provide high-resolution spectra, they consist of complex experimental techniques and are not suitable for semiconductor cavities operating at a wide range of optical wavelengths. We develop a pragmatic experimental approach for conventional Brillouin spectroscopy that can integrate a widely tunable excitation-source. Our setup combines a fibered-based angular filtering and a spectral filtering based on a rotating single etalon and a double grating spectrometer for sequential reconstruction of Brillouin spectra. This configuration allows probing confined acoustic phonon modes in the 20-300â GHz frequency range with excellent laser rejection and high spectral resolution. Remarkably, our scheme based on the excitation and collection of the enhanced Brillouin scattering signals through the optical cavity allows for better angular filtering with decreasing phonon frequency. It can be implemented for the study of cavity optomechanics and stimulated Brillouin scattering over broadband optical and acoustic frequency ranges.
RESUMO
The pursuit of a physiological indicator of noxious stimulation is desirable as it has the potential to provide mechanistic information regarding acute pain and may ultimately improve pain management strategies. Currently, there are no specific neurophysiological markers of pain to evaluate treatments. Recent attempts to identify neural correlates of pain have focused on different neuroimaging modalities. The purpose of this review is to discuss common neuroimaging techniques and findings thus far.
Assuntos
Encéfalo/diagnóstico por imagem , Eletroencefalografia/métodos , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Medição da Dor/métodos , Dor/diagnóstico por imagem , Encéfalo/fisiopatologia , Ritmo Gama , Humanos , Dor/fisiopatologiaRESUMO
Human Machine Interfaces (HMIs) can provide critical support and improve daily task functionality for prosthesis users or social interaction for patients with locked-in syndrome using an assistive communication device. One goal in the development of sophisticated HMIs is to reduce the cognitive load (CL) they place on the user to promote the use of the technology. Electroencephalogram (EEG)-derived measures collected with wired wet-electrode systems have been used to assess CL in laboratory environments and have demonstrated acceptable test-retest reliability. Assessment of CL during real-world unconstrained HMI operation, however, requires the use of a wireless dry-electrode EEG system which provides easier electrode application and untethered movement. However, the test-retest reliability of wireless dry-electrode systems to quantify CL has not been explored. Ensuring the consistent capture of CL-related signals across multiple sessions is critical if these devices are to be used to assess how improvements in HMIs affect CL. Therefore, the current study used a wireless dry-electrode EEG system to compare Evoked Response Potential (ERP) features of a simple auditory oddball task to measure CL during two separate testing sessions a week apart. ERPs of 11 subjects were recorded while participants performed a virtual task at two difficulty levels. A significant correlation was found between the P300 component of the ERPs and subjective ratings of CL during both testing sessions. Furthermore, there was a statistically significant test-retest reliability for this same ERP feature and similar signal-to-noise ratios (SNRs) across sessions.Clinical Relevance- This is an initial step in validating wireless dry-electrode EEG systems to assess cognitive load across multiple sessions. The evidence presented is critical if dry-wireless EEG systems are to be used to identify aspects of HMIs that reduce CL in clinical and real-life environments. Assessing CL in unconstrained environments can better inform clinicians and technology developers in their design of future HMIs.
Assuntos
Eletroencefalografia , Potenciais Evocados , Cognição , Eletrodos , Humanos , Reprodutibilidade dos TestesRESUMO
Phosphate removal is an important factor that must be taken into account in eutrophized waters. For this reason, many studies on different ways of removing phosphates from water have been published nowadays. In this work, a comparative study between the use of graphene oxide (GO) and graphene oxide functionalized with silver nanoparticles (GO@AgNPs) as adsorbents to remove phosphates from water samples has been carried out. Experimental conditions, including the pH, adsorbent dose, contact time and temperature, have been analyzed to achieve the highest adsorption efficiency. Although both adsorbents can be considered suitable for removing phosphates from aqueous solutions, GO@AgNPs provided a maximum removal efficiency of 100%, reaching the equilibrium conditions instantaneously under straightforward experimental conditions. Moreover, a much lower adsorbent dose was necessary than with graphene oxide. When GO was used, the maximum removal efficiency was 75%, 9â¯min were necessary to reach the equilibrium conditions and 20â¯mg of adsorbent were needed. Both adsorbents can be regenerated in an acid medium, giving recovery percentages of 98% and 80% for GO and GO@AgNPs respectively, which allows them to be recycled and used again.
RESUMO
Adhesions between lumbricales and interossei muscles are known as "saddle deformities." Clinical diagnosis of saddle deformities of the hand requires a high index of clinical suspicion; this specific injury is often missed or remains undiagnosed using conventional X-ray or MRI techniques. Although the "gold standard" for treatment is surgical release of the adhesions, ultrasound-guided steroid injections at the site of adhesions could be considered a promising treatment option prior to surgical management and, as illustrated in this case, is shown to provide adequate pain relief and positive outcomes for the patient.
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Glucocorticoides/administração & dosagem , Injeções Intramusculares , Aderências Teciduais/tratamento farmacológico , Ultrassonografia de Intervenção , Adulto , Dexametasona/administração & dosagem , Dexametasona/análogos & derivados , Mãos/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Aderências Teciduais/diagnóstico por imagem , Escala Visual AnalógicaRESUMO
INDRODUCTION: Trigger finger is very common in the population, with a life-threatening risk of developing the disease of 2.6% in the general population and increasing to 4 to 10% in diabetics. Since there is no standard gold of surgical treatment and there is still controversy in this, it is important to evaluate the results of the different surgical techniques. The objective of this study is to evaluate postoperative results of both surgical techniques in patients with follow-up of 1 to 12 months postoperative. MATERIAL AND METHODS: It is a prospective, longitudinal, descriptive and observational study carried out in a period from January 2015 to December 2017. Postoperative open (group 1) and percutaneous needle (group 2) patients were included. All patients were reviewed and surveyed by telephone. The comparison results of both techniques were analyzed using 2 for parametric results and by the Fisher test for nonparametric results. RESULTS: It was found that patients in group 2 expressed greater satisfaction, where 21.8% (n = 12) were fully satisfied with the percutaneous procedure, unlike those in group 1 where total satisfaction was only manifested at 3.8% (n = 2). CONCLUSIONS: In this study we can conclude that both techniques are effective for the treatment of trigger finger, with percutaneous needle release offering the highest degree of satisfaction in patients.
INTRODUCCIÓN: El dedo en gatillo es muy frecuente en la población, con un riesgo de vida de padecer la enfermedad de 2.6% en la población general y con un aumento de 4 a 10% en diabéticos. Dado que no hay un estándar de oro de tratamiento quirúrgico y aún hay controversia en ello, es importante evaluar los resultados de las distintas técnicas quirúrgicas. El objetivo de este estudio es evaluar resultados postoperatorios de ambas técnicas quirúrgicas en pacientes con seguimiento de uno a 12 meses de postoperatorio. MATERIAL Y MÉTODOS: Se trata de un estudio prospectivo, longitudinal, descriptivo y observacional realizado en un período de Enero de 2015 a Diciembre de 2017. Se incluyeron pacientes postoperados de liberación con técnica abierta (grupo 1) y percutánea con aguja (grupo 2). Se llevó a cabo la revisión de expedientes de todos los pacientes y se les hizo una encuesta mediante vía telefónica. Los resultados de la comparación de ambas técnicas se analizaron mediante 2 para resultados paramétricos y mediante la prueba de Fisher para los no paramétricos. RESULTADOS: Se encontró que los pacientes del grupo 2 manifestaron mayor satisfacción, de los cuales 21.8% (n = 12) estuvieron totalmente satisfechos con el procedimiento percutáneo, a diferencia de los del grupo 1 quienes manifestaron satisfacción total sólo en 3.8% (n = 2). CONCLUSIONES: En este estudio podemos concluir que ambas técnicas son efectivas para el tratamiento de dedo en gatillo, siendo la liberación percutánea con aguja la que ofrece mayor grado de satisfacción en los pacientes.
Assuntos
Procedimentos Ortopédicos , Dedo em Gatilho/cirurgia , Humanos , Período Pós-Operatório , Estudos Prospectivos , Resultado do TratamentoRESUMO
Anaerobically-digested sludge called fresh sludge (F), composted sludge (C) and thermally-drying sludge (T), all from the same batch, were applied to the surface of a calcareous Udic Calciustept with loamy texture. Dosage equivalent was 10 t ha(-1) of dry matter. The concentration of mineral nitrogen (ammonium and nitrate) in the soil was measured in order to estimate the effects of the post-treatments to which the different kinds of sewage sludge are subjected in relation to the availability of N in the surface layer of the soil. The most significant differences in NH(4)-N and NO(3)-N concentrations due to the transformation of the organic matter were observed during the first three weeks following soil amendment. Thermally-dried and composted sludge initially displayed higher concentrations of ammonium and nitrate in soil. Five months after the amendment, soil applied with fresh sludge showed the highest concentrations of NH(4)-N and NO(3)-N (6.1 and 36.6 mg kg(-1), respectively). It is clear that the processes of composting and thermal-drying influence the bioavailability of nitrogen from the different types of sewage sludge.
Assuntos
Nitrogênio/análise , Esgotos/análise , Solo/análise , Clima , Incêndios , Umidade , Fenômenos Fisiológicos Vegetais , Chuva , Dióxido de Silício , Espanha , TemperaturaRESUMO
In order to evaluate potential toxic effects of stabilized sewage sludge that are currently applied to agricultural soils, three types of municipal sewage sludge and one pig slurry were subjected to phytotoxicity assays using three plants (Brassica rapa, Lolium perenne and Trifolium pratense). Equivalent batches of aerobically and anaerobically-digested sludge (F) from two municipal wastewater treatment plants, were composted (C) or thermally dried (T). In addition, one anaerobically-digested and thermally-dried pig slurry (P) was tested. A seedling growth test was performed in accordance with the OECD Guideline 208A, using seed emergence and shoot length as endpoints to identify the inhibition of plants growing in increasing doses of sludge. A correlation analysis between EC50 and physico-chemical parameters or the pollutant burden of the biosolids was also calculated. In all tests, lower germination rates were observed for T. pratense than for L. perenne and B. rapa. A moderate stimulatory effect on shoot length at low doses was observed for the three plants. In these wastes, a strong positive correlation was found between higher values of EC50 (less toxicity) and the stability degree of their organic matter, and a negative correlation between EC50 and total N, hydrolysable N or NH4-N content. No correlations were found with heavy metal or organic pollutant content in those wastes. Results indicate that digested sludge, thermally-dried sludge and thermally-dried pig slurry have non-negligible short term phytotoxic effects, and confirm that composting is an effective sludge treatment for the reduction of phytotoxicity.
Assuntos
Esterco , Desenvolvimento Vegetal , Esgotos , Solo , Animais , SuínosRESUMO
La Granulomatosis con Poliangeítis (GPA), o Granulomatosis de Wegener, es una vasculitis sistémica de pequeño y mediano vaso inmunológicamente mediada, que preferentemente compromete la vía aérea superior, pulmones y riñones, y es poco frecuente que se asocie a manifestaciones cardíacas. El compromiso del sistema éxcitoconductor (SEC) es muy raro y se han descrito casos aislados de distintos grados de bloqueo aurículoventricular (BAV). Describimos el caso de un paciente con GPA que durante una recidiva de su enfermedad consultó por disnea, documentándose signos de bajo débito, bradicardia de 30/ min, BAV de 2° grado avanzado y bloqueo completo de rama izquierda (BCRI) en el electrocardiograma (ECG). Se presenta una revisión de la literatura y discutimos sus causas, la evolución y manejo de estos pacientes.
Granulomatosis with Polyangiitis (GPA), or Wegener's Granulomatosis, is an immunologically mediated systemic vasculitis of small and medium vessels, which commonly compromises the upper airway, lungs, and kidneys and is rarely associated with cardiac manifestations. Compromise of the cardiac conduction system is rare, and isolated cases of different degrees of atrioventricular block (AVB) have been described. We report a case of a 49-year-old male patient previously diagnosed with GPA 3 years ago, who presented to the emergency department with dyspnea, clinical signs of low output, bradycardia of 30/min, advanced second-degree AVB and complete left bundle branch block (LBBB) on the ECG. A literature review is presented, and we discuss the causes, evolution, and management of this GPA complication.
RESUMO
To explore our hypothesis of a direct reticulocyte origin of irreversibly sickled cells (ISCs), we fractionated light, reticulocyte-rich, and discocyte-rich sickle anemia red cells on Stractan gradients, and examined the effects of deoxygenation-induced sickling, external Ca2+, acidification, and replacing external Na+ by impermeant N-methyl-D-glucamine (NMG+). Sickling permeabilized light reticulocyte-rich cells to cations (Na+, K+, and Ca2+) more than discocytes; without external Ca2+, Na+ influx matched K+ efflux, with stable cell volume; with Ca2+, many light, low hemoglobin (Hb) F reticulocytes dehydrated rapidly (preventable by quinine, a Ca2(+)-dependent K+ channel inhibitor). Acidification of oxygenated discocytes (high mean Hb F) and reticulocyte-rich fractions yielded denser, reticulocyte-enriched cells with lower Hb F (as in light reticulocyte or dense ISC-rich fractions). Light cells shrank when NMG+ replaced Na+, supporting predictions of a Na(+)-dependent volume control system. Demonstration of sickling-induced, Ca2(+)-dependent dehydration of Hb F-free reticulocytes, and conservation of acid-stimulated K:Cl cotransport among low Hb F, reticulocyte-enriched cells in discocyte fractions support the hypothesis. Ancillary new findings included heparin stimulation of sickling-induced Na+ and K+ permeabilizations, and Ca2+ inhibition of the Na+ leak.
Assuntos
Anemia Falciforme/sangue , Eritrócitos/metabolismo , Reticulócitos/metabolismo , Anemia Falciforme/metabolismo , Água Corporal/metabolismo , Cálcio/sangue , Cálcio/farmacologia , Permeabilidade da Membrana Celular , Hemoglobina Fetal/análise , Heparina/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Potássio/sangue , Quinina/farmacologia , Sódio/sangueRESUMO
To explore basic properties of the sickling-induced cation permeability pathway, the Ca2+ component (Psickle-Ca) was studied in density-fractionated sickle cell anemia (SS) discocytes through its effects on the activity of the cells' Ca2+sensitive K+-channels (KCa). The instant state of KCa channel activation was monitored during continuous or cyclic deoxygenation of the cells using a novel thiocyanate-densecell formation method. Each deoxy pulse caused a reversible, sustained Psickle-Ca, which activated KCa channels in only 10-45% of cells at physiological [Ca2+]o ("activated cells"). After removal of cells activated by each previous deoxy pulse, subsequent pulses generated similar activated cell fractions, indicating a random determination rather than the response of a specific vulnerable subpopulation. The fraction of activated cells rose monotonically with [Ca2+]o along a curve reflecting the cells' distribution of Psickle-Ca, with values high enough in a small cell fraction to trigger near-maximal KCa channels. Consistent with the stochastic nature of Psickle-Ca, repeated deoxygenated-oxygenated pulsing led to progressive dense cell formation, whereas single long pulses caused one early density shift. Thus deoxygenation-induced Ca2+-permeabilization in SS cells is a probabilistic event with large cumulative dehydrating potential. The possible molecular nature of Psickle-Ca is discussed.
Assuntos
Anemia Falciforme/patologia , Cálcio/metabolismo , Eritrócitos/patologia , Canais de Potássio/metabolismo , Anemia Falciforme/metabolismo , Membrana Eritrocítica/metabolismo , Eritrócitos/metabolismo , Humanos , Transporte de ÍonsRESUMO
We developed a mathematical model of the reticulocyte, seeking to explain how a cell with similar volume but much higher ionic traffic than the mature red cell (RBC) regulates its volume, pH, and ion content in physiological and abnormal conditions. Analysis of the fluxbalance required by reticulocytes to conserve volume and composition predicted the existence of previously unsuspected Na(+)-dependent Cl- entry mechanisms. Unlike mature RBCs, reticulocytes did not tend to return to their original state after brief perturbations. The model predicted hysteresis and drift in cell pH, volume, and ion contents after transient alterations in membrane permeability or medium composition; irreversible cell dehydration could thus occur by brief K+ permeabilization, transient medium acidification, or the replacement of external Na+ with an impermeant cation. Both the hysteresis and drift after perturbations were shown to depend on the pHi dependence of the K:Cl cotransport, a major reticulocyte transporter. This behavior suggested a novel mechanism for the generation of irreversibly sickled cells directly from reticulocytes, rather than in a stepwise, progressive manner from discocytes. Experimental tests of the model's predictions and the hypothesis are described in the following paper.
Assuntos
Anemia Falciforme/metabolismo , Água Corporal/metabolismo , Eletrólitos/metabolismo , Modelos Biológicos , Reticulócitos/metabolismo , Transporte Biológico , Permeabilidade da Membrana Celular , Humanos , Concentração de Íons de Hidrogênio , Matemática , Potenciais da MembranaRESUMO
The total and DTPA-extractable concentrations of Pb, Ni, Zn, Cu, Cr and Cd were measured in a calcareous soil amended with different doses of sewage sludge under field conditions. The same metals were also measured in the roots and leaves of Dactylis glomerata at the end of the first vegetative period after the sludge was added. The root concentrations of all the metals were unrelated to their concentrations in the soil. Leaf concentrations of Zn and Cr correlated with total (Zn) and DTPA-extractable (Zn and Cr) concentrations in the soil. DTPA extraction did not appear to be very useful for evaluating the bioavailability of metals in this kind of soil as it gave very low correlation coefficients with leaf content (r = 0.684, P = 0.0049 for Zn and r = 0.557, P = 0.0249 for Cr). Concentrations of Pb, Ni, Cu, and Cd in roots and leaves of Dactylis glomerata were unrelated to the total or DTPA-extractable concentrations in the sludge-amended soil.
Assuntos
Dactylis/metabolismo , Metais Pesados/farmacocinética , Esgotos , Solo/análise , Disponibilidade Biológica , Metais Pesados/análise , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Espanha , Espectrofotometria AtômicaRESUMO
Lithium intoxication has a low prevalence, the 75% of patients with treatment with lithium could have toxic levels of lithium during the treatment. Asymptomatic patients have been observed with doses under 2.5 mmol/L. Systems with high prevalence of symptoms are the nervous system, gastrointestinal tube and cardiovascular. Symptoms could appear from two hours to four hours after ingestion. Early hours after lithium ingestion, levels of lithium are not related with severity. However, monitoring seric levels is necessary to lead therapeutic approach and to give a prognosis. Induce urine with isotonic solution, is used during therapeutic approach. Other therapeutic option is dialysis. In summary, intoxication with lithium could be a severe situation. It is necessary to describe therapeutic protocols in this entity.
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Compostos de Lítio/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/diagnóstico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/terapia , Humanos , Compostos de Lítio/farmacologia , Compostos de Lítio/uso terapêuticoAssuntos
Baclofeno/intoxicação , Coma/induzido quimicamente , Eletroencefalografia/efeitos dos fármacos , Relaxantes Musculares Centrais/efeitos adversos , Tétano/tratamento farmacológico , Baclofeno/administração & dosagem , Baclofeno/uso terapêutico , Coma/diagnóstico por imagem , Coma/fisiopatologia , Overdose de Drogas , Emergências , Evolução Fatal , Feminino , Humanos , Imunização Passiva , Injeções Intramusculares/efeitos adversos , Metronidazol/uso terapêutico , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos , Relaxantes Musculares Centrais/administração & dosagem , Relaxantes Musculares Centrais/uso terapêutico , Antitoxina Tetânica/uso terapêutico , Ultrassonografia Doppler TranscranianaRESUMO
Axoplasm from freshly isolated Myxicola giant axons was mixed with small volumes of 'artificial axoplasm' containing 45Ca and either CaEGTA/EGTA or CaDTPA/DTPA buffers giving various nominal values of [Ca2+]. The axoplasm samples were centrifuged at 100 000 X g for 30 min to form a pellet and the percentage of 45Ca bound to the pellet was determined. The fraction of bound calcium rose with increasing values of [Ca2+] along an S-shaped curve. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) was used to reveal the presence of mitochondrial Ca uptake. At physiological values of [Ca2+], around 100 nM, Ca uptake was insensitive to FCCP. As [Ca2+] was elevated, increasing sensitivity to FCCP was noted above [Ca2+] = 0.5 microM. At low values of [Ca2+], including the physiological range, Ca binding was significantly reduced by vanadate and quercetin, agents known to inhibit Ca uptake mediated by Ca2+-activated ATPase reactions. Inhibition of Ca binding by these agents was approximately 50% at physiological values of [Ca2+]. ATP depletion decreased the percentage of Ca binding by the pellet at physiological [Ca2+]. The results suggest that about 50% of the Ca buffering by particulate matter in axoplasm is via organelles requiring intact Ca2+-ATPase reaction at physiological values of [Ca2+].
Assuntos
Trifosfato de Adenosina/metabolismo , Axônios/ultraestrutura , Cálcio/metabolismo , Organoides/metabolismo , Animais , Calcimicina/farmacologia , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Microscopia Eletrônica , Poliquetos/metabolismo , Quercetina/farmacologia , Vanadatos , Vanádio/farmacologiaRESUMO
The membrane potential (Em) of sartorius muscle fibers was made insensitive to [K+] by equilibration in a 95 mM K+, 120 mM Na+ Ringer solution. Under these conditions a potassium-activated, ouabain-sensitive sodium efflux was observed which had characteristics similar to those seen in muscles with Em sensitive to [K+]. In addition, in the presence of 10 mM K+, these muscles were able to produce a net sodium extrusion against an electrochemical gradient which was also inhibited by 10- minus 4 M oubain. This suggests that the membrane potential does not play a major role in the potassium activation of the sodium pump in muscles.
Assuntos
Potenciais da Membrana/efeitos dos fármacos , Músculos/fisiologia , Potássio/farmacologia , Sódio/metabolismo , Animais , Anuros , Membro Posterior , Músculos/metabolismo , Concentração Osmolar , Ouabaína/farmacologiaRESUMO
When frog sartorius muscles recover from Na enrichment in the presence of external K, net K entry into the fibers occurs by both passive movement and active inward transport via a K pump. Under normal conditions, it has not been possible to experimentally distinguish these processes. Fractionation into the flux components must be accomplished from inferences concerning the K conductance or permeability during a period of rapid Na extrusion. The best estimates indicate that 60-80% of the K entry occurs via the K pump. In the presence of Ba ions, the membrane permeability to K is very much reduced. Under these conditions, Na-enriched muscles underwent a normal recovery in the presence of external K, and the amount of inward K movement due to the K pump rose to over 90% of the total K entry. The characteristics of the K pump studied by this means were: (a) essentially complete inhibition by 10(-4) M ouabain, (b) inhibition by [Na]omicron, (c) activation by [K]omicron according to a rectangular hyperbola in the absence of [Na]omicron, (d) linear activation by [Na]iota over a wide range in concentration, (e) zero or undetectably low pumping rate as [Na]iota leads to 0, (f) the number of Na ions actively transported per K ion actively transported is 1.4-1.7 normally and 1.1 in the presence of Ba.
Assuntos
Bário/metabolismo , Músculos/metabolismo , Potássio/metabolismo , Animais , Anuros , Permeabilidade da Membrana Celular , Técnicas In Vitro , Potenciais da Membrana , Músculos/fisiologia , Ouabaína/farmacologia , Rana pipiens , Sódio/metabolismoRESUMO
This study tested the hypothesis that black females have an increase in skeletal muscle and bone mineral mass compared with white females matched for age (+/- 5 y), weight (+/- 2 kg), height (+/- 3 cm), and menstrual status. Conventional [underwater weighing, whole body 40K counting (WBC), 3H2O dilution] and newly developed (dual-photon absorptiometry) techniques were used to provide ethnicity-independent estimates of body composition in 28 pairs of matched subjects. Black females had greater appendicular skeletal muscle (P less than 0.001), bone mineral (P less than 0.001), and total body potassium (TBK) (P = 0.05) compared with white females. Two classic coefficients used in body composition research [density of fat-free mass (FFM) for underwater weighing and TBK/FFM for WBC] differed significantly (P less than 0.05) between black and white females; currently applied coefficients underestimated fat in black females. This study confirms that black and white females differ in body composition and that errors in fat estimates occur when ethnicity is not accounted for in body composition models.