Extracellular action potentials and isometric contractile tension have been recorded simultaneously in vitro from uterine longitudinal smooth muscle of the pregnant cat, pregnant rabbit, estrogen-treated rabbit, and estrogen-treated rat. Action potentials were recorded from the surface of the muscle strips with glass electrodes having a large tip diameter. Tension was recorded with an RCA transducer. Spontaneous contractions are associated with a series of action potentials. During relaxation no electrical activity is observed. Electrical and mechanical activities were first recorded in Kreb's Ringer medium and then in sodium-poor media (replacement of sodium chloride with choline chloride or sucrose). Sufficient reduction in the external sodium concentration resulted in increased amplitude (peak to peak) of the biphasic action potential spikes. The duration of the peak to peak deflection and the maximum rate of potential, change remained unchanged. However, decrease in the external sodium concentration reduced the frequency of the action potentials, considerably in the cat, and less so in the rabbit and rat. The external sodium concentration was reduced in stepwise ; fashion to ½, ¼ , ⅛ its initial value. Each successive decrease in the external sodium concentration was accompanied by a prompt initial contraction, followed by very slow relaxation and subsequent resumption of spontaneous contractions accompanied by action potentials. With cat uteri reduction of the sodium concentration of the medium to a level of 15-20 mEq/1 resulted in a greatly prolonged contraction with eventual relaxation when tissues failed to contract. This paralysis was associated with cessation of action potentials. The electrical responses of uteri of the other two species (rabbit and rat) during exposure to sodium-poor media were similar to those observed with the cat uterus. However, the mechanical activity of rat and rabbit uteri in sodium poor media was different from that of the cat uterus. Decrease in the external sodium concentration below 25-30 mEq/1 usually resulted in prolonged contractions, and finally to complete failure of the tissue to relax (even after 2-2½ hours). Outbursts of action potentials at irregular intervals were seen in the initial stages of this persistent contraction but eventually action potentials also disappeared. It was difficult to reconcile these facts with the "Sodium Hypothesis". A selective inward flow of sodium ions probably cannot account for the initiation of action potentials in uterine smooth muscle since considerable reduction of the external sodium concentration (down to 15-20 mEq/1 in cat and 25-30 mEq/1 in the other two species) did not affect the characteristics of the action potentials in the expected manner. However, further reduction in sodium did result in electrical and mechanical inactivity. The view that an outward flow of intracellular anions might be responsible for depolarization (14) receives further support from the present studies. In addition to many differences from other types of excitable tissue (nerve, cardiac and skeletal muscle), uterine smooth muscle also shows considerable intra- and inter-species variation. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

Utilizing non-metabolizable substrates as valuable tools to differentiate between transport and subsequent metabolism, the possibility was explored whether there was a relationship between the sodium requirement by marine bacterial cella for growth and a sodium requirement for uptake of substrates. Various aspects of the transport phenomenen in these organisms were studied and the following findings are claimed to constitute a contribution to knowledge. [...]

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Eight well-trained male and female cyclists were studied to determine the effect of sodium and/or water intake on plasma aldosterone during six hours of cycling (55% VO2max) in a warm environment (Tdb = 350C WBGT = 30°C). Each subject randomly completed three trials (water = W; saline = S and no fluid = NF) at one week intervals. Venous blood samples were obtained before dehydration, at 2, 4, 5 and 6 hours during exercise, and also after dehydration. Plasma samples were analyzed for hemoglobin, sodium, potassium, aldosterone and osmolality. Sweat and urine samples were also collected and analyzed for sodium content. Plasma volume based on hemoglobin decreased significantly ( P < 0.01 ) at 15 min in all three trials (Trial W = -7.6%±1.12%; Trial S = -8.6%±1.42% and Trial NF = -6.7%±0.88%) and continued to decrease significantly in Trial NF during exercise ( -10.99% ± 1.3% at the 2th hr; -15.5% ±1.3% at the 4th hr and -16.8%±1.32% at the 5th hr).No significant differences were found betwee trials. Plasma sodium concentration [Na+] decreased over time in Trials W and S and increased in Trial NF due to plasma volume loss. Significant differences in [ Na+ ] were found between Trial NF and Trials W or S. Plasma sodium [Na+ ] adjusted by plasma volume change decreased significantly at 2 hours ( P < 0.01) in the three trials. Average total sodium content of plasma decreased by 125.9 mEq during Trial S, 223.1 mEq during Trial W and 147.1 mEq during Trial NF. Plasma potassium increased significantly (P < 0.01) at 2 hours in all three trials. Plasma osmolality increased significantly (P < 0.01) during prolonged exercise (Trial W = 287.1±2.4 mEq/l; Trial S = 289.4±1.17 mEq/1 and Trial NF = 306±1.6 mEq/1). No significant differences were found between Trials W and S although osmolality was lower in Trial W than in Trial S. A significant difference in osmolality was obtained between Trial NF and Trials W and S (P < 0.01). Plasma aldosterone increased significantly (P < 0.01) during exercise and decreased after exercise. No significant differences existed between Trials W and S although aldosterone levels were lower in Trial S than in Trial W. However, a significant difference was found between Trial NF and Trials W or S. The results of this study suggest that plasma aldosterone has an inverse relationship with plasma volume changes and total sodium concentrations. An increase in plasma potassium and a decrease in plasma sodium during prolonged exercise in a warm environment significantly enhanced plasma aldosterone concentration. The intake of water significantly decreased plasma aldosterone during prolonged exercise in a warm environment, but the intake of sodium had no significant effect in this study. / School of Physical Education

Orientador: Pasqual Barreti / Banca: Thyago Proença de Moraes / Banca: Aline de Araujo Antunes / Banca: Luis Cuadrado Martins / Banca: Francieli Cristina Delatim Vannini / Resumo: O prognóstico de pacientes com doença renal crônica (DRC) é fortemente influenciado por complicações cardiovasculares. A inflamação é sabidamente um dos fatores de risco para essas complicações, ocorrendo em cerca de 30% dos pacientes dialisados. Crescente número de publicações têm sugerido que a expansão de volume é uma das causas de inflamação nesses pacientes. Em estudo prévio em nosso Serviço observou-se que a redução do conteúdo de sódio (Na) na dieta e na solução de diálise se associaram à redução da concentração dos marcadores inflamatórios em pacientes em hemodiálise (HD). Entretanto, em ambos os estudos não observou a redução nos marcadores de volume de água corporal. Esses achados podem ser devidos à pouca sensibilidade dos marcadores de volume utilizados ou sugerir um papel direto do Na, como indutor de inflamação independente do volume. O presente trabalho objetiva confirmar a hipótese que a mobilização de sódio reduz o volume de água corporal e atenua o estado inflamatório em pacientes em HD, utilizando-se um marcador de volume mais sensível, o peptídeo natriurético atrial-B (BNP). Foram incluídos 98 pacientes, divididos em três grupos: dieta, tratado com redução de 2 g/dia de ingestão de Na; dialisato, submetido à redução da concentração de Na na solução de diálise de 138 para 135 mEq/L e controle. Os pacientes foram acompanhados por 16 semanas. Quanto às características basais não houve diferenças significantes entre os grupos. Os dados clínicos, como: pressão arterial, ganho de peso interdialítico, medicações, hipotensão e câimbras não variaram significantemente nos grupos estudados. As concentrações séricas dos marcadores bioquímicos não apresentaram alterações significantes entre os grupos, com exceção à saturação de transferrina no grupo dieta que apresentou um aumento na 8ª semana em relação ao momento inicial. Os marcadores ... / Abstract: The prognosis of chronic kidney disease patients is strongly influenced by cardiovascular complications. Inflammation is known to be one of the risk factors for these complications, occurring in about 30% of dialysis patients. Increasing evidences have suggested that the volume overload is one of the causes of inflammation in these patients. In a previous study in our center, we found that reducing the sodium content (Na) in the diet and in dialysis solution were associated with reduced concentrations of inflammatory markers in patients on hemodialysis (HD). However, in both studies a reduction in markers of body water volume was not found. These results could be due to the low sensitivity of the volume markers used or suggest a direct role of Na as an inflammatory inducer independent of the volume. The present study aims to confirm the hypothesis that the mobilization of sodium reduces the body water volume and attenuates the inflammatory state in HD patients, using a more sensitive volume marker as the type B atrial - natriuretic peptide (BNP). Ninety-eighty patients were included and randomly allocated into three groups: diet, treated with reduction of 2 g/day of dietary Na intake; dialysate, exposed to reduction of dialysate Na concentration from 138 to 135 mEq/L, and control group. The patients were followed up for 16 weeks. The baseline characteristics were similar among the groups. Clinical data, such as blood pressure, interdialytic weight gain; medications prescription, hypotension and cramps did not vary significantly among the groups. Serum concentrations of biochemical markers showed no significant changes among the groups, except for transferrin saturation, which showed an increase at week 8 comparing to initial evaluation in the diet group. Hematological markers did not change in diet and control groups, but in the dialysate group, a significant increase in hematocrit and hemoglobin levels were observed in the follow ... / Doutor

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Made available in DSpace on 2015-06-17T19:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-30. Added 1 bitstream(s) on 2015-06-18T12:48:14Z : No. of bitstreams: 1 000825096.pdf: 336330 bytes, checksum: fdddedb58765301dee1154260b8af6e9 (MD5) / O prognóstico de pacientes com doença renal crônica (DRC) é fortemente influenciado por complicações cardiovasculares. A inflamação é sabidamente um dos fatores de risco para essas complicações, ocorrendo em cerca de 30% dos pacientes dialisados. Crescente número de publicações têm sugerido que a expansão de volume é uma das causas de inflamação nesses pacientes. Em estudo prévio em nosso Serviço observou-se que a redução do conteúdo de sódio (Na) na dieta e na solução de diálise se associaram à redução da concentração dos marcadores inflamatórios em pacientes em hemodiálise (HD). Entretanto, em ambos os estudos não observou a redução nos marcadores de volume de água corporal. Esses achados podem ser devidos à pouca sensibilidade dos marcadores de volume utilizados ou sugerir um papel direto do Na, como indutor de inflamação independente do volume. O presente trabalho objetiva confirmar a hipótese que a mobilização de sódio reduz o volume de água corporal e atenua o estado inflamatório em pacientes em HD, utilizando-se um marcador de volume mais sensível, o peptídeo natriurético atrial-B (BNP). Foram incluídos 98 pacientes, divididos em três grupos: dieta, tratado com redução de 2 g/dia de ingestão de Na; dialisato, submetido à redução da concentração de Na na solução de diálise de 138 para 135 mEq/L e controle. Os pacientes foram acompanhados por 16 semanas. Quanto às características basais não houve diferenças significantes entre os grupos. Os dados clínicos, como: pressão arterial, ganho de peso interdialítico, medicações, hipotensão e câimbras não variaram significantemente nos grupos estudados. As concentrações séricas dos marcadores bioquímicos não apresentaram alterações significantes entre os grupos, com exceção à saturação de transferrina no grupo dieta que apresentou um aumento na 8ª semana em relação ao momento inicial. Os marcadores ... / The prognosis of chronic kidney disease patients is strongly influenced by cardiovascular complications. Inflammation is known to be one of the risk factors for these complications, occurring in about 30% of dialysis patients. Increasing evidences have suggested that the volume overload is one of the causes of inflammation in these patients. In a previous study in our center, we found that reducing the sodium content (Na) in the diet and in dialysis solution were associated with reduced concentrations of inflammatory markers in patients on hemodialysis (HD). However, in both studies a reduction in markers of body water volume was not found. These results could be due to the low sensitivity of the volume markers used or suggest a direct role of Na as an inflammatory inducer independent of the volume. The present study aims to confirm the hypothesis that the mobilization of sodium reduces the body water volume and attenuates the inflammatory state in HD patients, using a more sensitive volume marker as the type B atrial - natriuretic peptide (BNP). Ninety-eighty patients were included and randomly allocated into three groups: diet, treated with reduction of 2 g/day of dietary Na intake; dialysate, exposed to reduction of dialysate Na concentration from 138 to 135 mEq/L, and control group. The patients were followed up for 16 weeks. The baseline characteristics were similar among the groups. Clinical data, such as blood pressure, interdialytic weight gain; medications prescription, hypotension and cramps did not vary significantly among the groups. Serum concentrations of biochemical markers showed no significant changes among the groups, except for transferrin saturation, which showed an increase at week 8 comparing to initial evaluation in the diet group. Hematological markers did not change in diet and control groups, but in the dialysate group, a significant increase in hematocrit and hemoglobin levels were observed in the follow ...