A comparative study for results obtained using biomonitors and PM10 collectors in Sado Estuary.

In 1996 a program was started, financed by the Environmental Ministry of Portugal and IAEA, aiming to study the inorganic atmospheric pollutant dispersion in Sado Estuary. Gent PM10 air samplers were used for air particulate matter sampling. Three sampling sites were chosen, forming a triangle around the fuel power station of Setúbal. Transplants of Parmelia sulcata Taylor were suspended in nylon bags within a rectangle 15 km wide and 25 km long on a 2.5 x 2.5 km grid. Two sets of four transplants were hung in each of the 47 locations, one set facing the wind and the other set opposing the wind. The transplants were suspended in December 1997 for a 1-year period; every 3 months, one transplant of each set was collected. Both lichen transplants and PM10 filters were analysed by INAA and PIXE. A comparative study of results obtained for the two sampling procedures is presented in this work.

[The dawn phenomenon in diabetic pregnancy]. / Estudio del fenómeno del alba en la embarazada diabética.

The possible development of the dawn phenomenon in three gestational stages was investigated in 9 pregnant women with type I diabetes mellitus and 10 with gestational diabetes. To this end, the overnight intravenous insulin infusion was evaluated with the artificial pancreas (Biostator). In none of the two clinical conditions and in none of the three gestational stages an increased insulin infusions during the second period of the night was found under the experimental conditions of our study. This finding may we related with the timing of the last food intake.

[Evaluation of the insulin requirements with an artificial pancreas in the pregnant woman with gestational insulin-dependent diabetes (type I)]. / Valoración de los requerimientos insulínicos con páncreas artificial en la embarazada con diabetes pregestacional insulinodependiente (tipo I).

The evolution of insulin requirements in 9 pregnant women with insulin-dependent diabetes mellitus (type I) was evaluated. Requirements were increased between weeks 11 and 24 and remained stable between weeks 24 and 35. Those corresponding to breakfast in the two initial connections were significantly higher, while those corresponding to breakfast, lunch and dinner became equal in the last connection (35 gestational weeks). We found a significant lineal correlation between the intravenous and the subcutaneous requirements. We conclude that the artificial pancreas is a useful instrument, which permits a detailed analysis of the time course of intravenous insulin requirements during pregnancy in the insulin-dependent pregnant woman and facilitates the adjustment of insulin therapy.

[Evaluation of the insulin requirements with an artificial pancreas in gestational diabetes]. / Valoración de los requerimientos insulínicos con páncreas artificial en la diabetes gestacional.

The evolution of insulin requirements in 10 patients with gestational diabetes mellitus was evaluated with the use of an artificial pancreas. We found that intravenous insulin requirements showed a definite tendency to decline, the greatest reduction being found between gestational weeks 27 and 37. Postprandial requirements after lunch were significantly higher in the weeks 15 and 27, with a tendency to become equal to those corresponding to breakfast and dinner in week 37. We found a lack of lineal correlation between the intravenous and subcutaneous requirements. We conclude that the artificial pancreas is a useful instrument to examine in detail the temporal evolution of insulin requirements in gestational diabetes. The artificial pancreas facilitates the adjustment of insulin therapy and plays a major role in the understanding of the pathophysiological abnormalities in these patients.

Intracellular binding of spin-labeled amiloride: an alternative explanation for amiloride's effects at high concentration.

Amiloride, an important inhibitor of Na+ transport and Na+/H+ exchange, has been used in nontransporting tissues to investigate the relationship between ionic fluxes or intracellular pH change and proliferative or synthetic events. Reports that amiloride is permeant and had direct effects on intracellular processes have led us to investigate the possibility that amiloride binds intracellularly to nuclei, mitochondria, and to purified nucleic acids. Using a nitroxide spin-labeled derivative of amiloride (ASp) and electron paramagnetic resonance (EPR) spectroscopy, we have demonstrated that nuclei and mitochondria isolated from trout liver bind significant amounts of ASp especially at the high amiloride concentrations (approximately mM) commonly used to inhibit proliferative events. While the chemical component responsible for ASp binding in these organelles was not identified, native DNA binds significant amounts of ASp whereas single stranded DNA and RNA bind much less. When these observations are taken together with reports of amiloride's direct action on cellular processes, they support the possibility that some of the effects attributed to inhibition of a transport event are caused by amiloride directly.

Identification of apical membranes from tight epithelia using spin-labeled amiloride and electron paramagnetic resonance spectroscopy.

Apical cell membranes from Na+-transporting epithelia were identified in centrifugal fractions prepared from homogenates of rainbow trout kidney, gill and frog skin using a spin-labeled, nitroxide derivative of amiloride and electron paramagnetic resonance spectroscopy. Spin-labeled amiloride (ASp) is a potent inhibitor of Na+ transport. Frog skin short-circuit current was inhibited by 50% in the presence of 7 X 10(-8) M ASp, whereas 4 X 10(-7) M amiloride was required to obtain the same effect. ASp is a suitable probe for the amiloride binding site based on analytical criteria: Unbound ASp produces an EPR signal linear with concentration and detectable at micromolar concentrations. Estimates of ASp binding can usually be made on less than 100 micrograms of membrane protein. While ASp binds nonspecifically to many materials, amiloride- or benzamil-displaceable binding occurred only in trout gill and kidney, and in frog skin, but not in trout skeletal muscle. ASp binds to membrane fractions produced by differential centrifugation of trout gill, kidney and frog skin. In trout gill and kidney, 81% and 91%, respectively, of the amiloride-displaceable ASp binding is found in the 10,000 X g fraction. All of the ASp binding in frog skin is found in the 10,000 X g fraction. These data indicate that spin-labeled amiloride is a useful probe for the identification of the amiloride binding site, and electron paramagnetic resonance spectroscopy will allow the amiloride binding site to be used as a molecular marker for apical membranes.