*Trabalho desenvolvido no Departamento de Nutrição da Faculdade de Saúde Pública da Universidade ... more *Trabalho desenvolvido no Departamento de Nutrição da Faculdade de Saúde Pública da Universidade de São Paulo e no Núcleo de Pesquisas Epidemiológicas em Nutrição e Saúde da Universidade de São Paulo e baseado em pesquisas de campo financiadas pela Financiadora de ...
The site dependence of the absorption-promoting actions of laureth-9, Na salicylate, Na2EDTA, and... more The site dependence of the absorption-promoting actions of laureth-9, Na salicylate, Na2EDTA, and aprotinin was studied in rats. Insulin absorption was estimated on the basis of the cumulative hypo-glycemic response from 0 to 4 hr postdose, relative to that after intramuscular insulin. Insulin was administered with or without adjuvants to isolated rectal, nasal, and buccal absorption sites. Laureth-9, a nonionic surfactant which irreversibly removes membrane proteins or lipids, promoted insulin absorption from each site. The rectal, nasal, and buccal routes were 30% as effective as the i.m. route. The enhancing effects of Na salicylate and Na2EDTA, which have reversible mechanisms of permeability enhancement, were specific for rectal absorption. With these adjuvants, rectal insulin was 30–40% as effective as i.m. insulin, but nasal and buccal doses were less than 5% as effective as i.m. doses. This specificity can be at least partly explained by considering the site-to-site differences in membrane histology, although differences in pore size and membrane biochemistry might also contribute. The protease inhibitor aprotinin was ineffective in increasing insulin efficacy via each route, either alone or in combination with laureth-9.
Page 1. 62 Rev Saúde Pública 2000;34(6 Supl):62-72 www.fsp.usp.br/rsp Tendência secular da anemia... more Page 1. 62 Rev Saúde Pública 2000;34(6 Supl):62-72 www.fsp.usp.br/rsp Tendência secular da anemia na infância na cidade de São Paulo (1984-1996)* Secular trends in child anemia in S. Paulo city, Brazil (1984-1996) Carlos ...
The purpose of this study was to identify the functional fields activated in relation to gestural... more The purpose of this study was to identify the functional fields activated in relation to gestural movements. Using functional magnetic resonance imaging (fMRI), we mapped brain activity in ten right-handed, normal volunteers during activation and control tasks. The activation condition consisted of pantomiming tool-use gestures with either the left hand or right hand, whereas the control condition comprised repetitive, oppositional movements between thumb and index finger. Activated cortical regions were highly lateralized to the left hemisphere during pantomiming of tool use regardless of hand used. Praxis with either hand commonly activated the superior parietal lobule, supplementary motor area, premotor area of the left hemisphere, and cerebellar vermis. However, minimal activation occurred in the inferior parietal lobule, which has been known to be a critical area for praxis generation. Compared with left-hand praxis, right-hand praxis exhibited additional activation in the left putamen and posterior part of the left inferior temporal region. Our findings concur with neuropsychological observations that the left hemisphere in right-handers mediates programming and executing skilled movements and that, within the left hemisphere, praxis is predominantly subserved by the parietal lobe, supplementary motor area, and premotor area. However, unlike previous lesion studies, the results of our fMRI study suggested that the superior parietal lobule more likely than the inferior parietal lobule play an important role in gesture production.
Na/K pump current (I(pump)) and intracellular Na concentration ([Na](i)) were measured simultaneo... more Na/K pump current (I(pump)) and intracellular Na concentration ([Na](i)) were measured simultaneously in voltage-clamped rabbit ventricular myocytes, under conditions where [Na](i) is controlled mainly by membrane transport. Upon abrupt pump reactivation (after 10-12 min blockade), I(pump) decays in two phases. Initially, I(pump) declines with little [Na](i) change, whereas the second phase is accompanied by [Na](i) decline. Initial I(pump) sag was still present at external [K] = 15 mM, but prevented by [Na](i) approximately 100 mM. Initial I(pump) sag might be explained by subsarcolemmal [Na](i) ([Na](SL)) depletion produced by rapid Na extrusion and I(pump). Brief episodes of pump blockade allowed [Na](SL) repletion, since peak postblockade I(pump) exceeded I(pump) at the end of previous activation (without appreciably altered global [Na](i)). The apparent K(m) for [Na](i) was higher for continuous I(pump) activation than peak I(pump) (14.1 +/- 0.2 vs. 11.2 +/- 0.2 mM), whereas that based on d[Na](i)/dt matched peak I(pump) (11.6 +/- 0.3 mM). [Na](SL) depletion (vs. [Na](i)) could be as high as 3 mM for [Na](i) approximately 18-20 mM. A simple diffusion model indicates that such [Na](SL) depletion requires a Na diffusion coefficient 10(3)- to 10(4)-fold below that expected in bulk cytoplasm (although this could be subsarcolemmal only). I(pump) integrals and [Na](i) decline were used to estimate intracellular Na buffering, which is slight (1.39 +/- 0.09).
*Trabalho desenvolvido no Departamento de Nutrição da Faculdade de Saúde Pública da Universidade ... more *Trabalho desenvolvido no Departamento de Nutrição da Faculdade de Saúde Pública da Universidade de São Paulo e no Núcleo de Pesquisas Epidemiológicas em Nutrição e Saúde da Universidade de São Paulo e baseado em pesquisas de campo financiadas pela Financiadora de ...
The site dependence of the absorption-promoting actions of laureth-9, Na salicylate, Na2EDTA, and... more The site dependence of the absorption-promoting actions of laureth-9, Na salicylate, Na2EDTA, and aprotinin was studied in rats. Insulin absorption was estimated on the basis of the cumulative hypo-glycemic response from 0 to 4 hr postdose, relative to that after intramuscular insulin. Insulin was administered with or without adjuvants to isolated rectal, nasal, and buccal absorption sites. Laureth-9, a nonionic surfactant which irreversibly removes membrane proteins or lipids, promoted insulin absorption from each site. The rectal, nasal, and buccal routes were 30% as effective as the i.m. route. The enhancing effects of Na salicylate and Na2EDTA, which have reversible mechanisms of permeability enhancement, were specific for rectal absorption. With these adjuvants, rectal insulin was 30–40% as effective as i.m. insulin, but nasal and buccal doses were less than 5% as effective as i.m. doses. This specificity can be at least partly explained by considering the site-to-site differences in membrane histology, although differences in pore size and membrane biochemistry might also contribute. The protease inhibitor aprotinin was ineffective in increasing insulin efficacy via each route, either alone or in combination with laureth-9.
Page 1. 62 Rev Saúde Pública 2000;34(6 Supl):62-72 www.fsp.usp.br/rsp Tendência secular da anemia... more Page 1. 62 Rev Saúde Pública 2000;34(6 Supl):62-72 www.fsp.usp.br/rsp Tendência secular da anemia na infância na cidade de São Paulo (1984-1996)* Secular trends in child anemia in S. Paulo city, Brazil (1984-1996) Carlos ...
The purpose of this study was to identify the functional fields activated in relation to gestural... more The purpose of this study was to identify the functional fields activated in relation to gestural movements. Using functional magnetic resonance imaging (fMRI), we mapped brain activity in ten right-handed, normal volunteers during activation and control tasks. The activation condition consisted of pantomiming tool-use gestures with either the left hand or right hand, whereas the control condition comprised repetitive, oppositional movements between thumb and index finger. Activated cortical regions were highly lateralized to the left hemisphere during pantomiming of tool use regardless of hand used. Praxis with either hand commonly activated the superior parietal lobule, supplementary motor area, premotor area of the left hemisphere, and cerebellar vermis. However, minimal activation occurred in the inferior parietal lobule, which has been known to be a critical area for praxis generation. Compared with left-hand praxis, right-hand praxis exhibited additional activation in the left putamen and posterior part of the left inferior temporal region. Our findings concur with neuropsychological observations that the left hemisphere in right-handers mediates programming and executing skilled movements and that, within the left hemisphere, praxis is predominantly subserved by the parietal lobe, supplementary motor area, and premotor area. However, unlike previous lesion studies, the results of our fMRI study suggested that the superior parietal lobule more likely than the inferior parietal lobule play an important role in gesture production.
Na/K pump current (I(pump)) and intracellular Na concentration ([Na](i)) were measured simultaneo... more Na/K pump current (I(pump)) and intracellular Na concentration ([Na](i)) were measured simultaneously in voltage-clamped rabbit ventricular myocytes, under conditions where [Na](i) is controlled mainly by membrane transport. Upon abrupt pump reactivation (after 10-12 min blockade), I(pump) decays in two phases. Initially, I(pump) declines with little [Na](i) change, whereas the second phase is accompanied by [Na](i) decline. Initial I(pump) sag was still present at external [K] = 15 mM, but prevented by [Na](i) approximately 100 mM. Initial I(pump) sag might be explained by subsarcolemmal [Na](i) ([Na](SL)) depletion produced by rapid Na extrusion and I(pump). Brief episodes of pump blockade allowed [Na](SL) repletion, since peak postblockade I(pump) exceeded I(pump) at the end of previous activation (without appreciably altered global [Na](i)). The apparent K(m) for [Na](i) was higher for continuous I(pump) activation than peak I(pump) (14.1 +/- 0.2 vs. 11.2 +/- 0.2 mM), whereas that based on d[Na](i)/dt matched peak I(pump) (11.6 +/- 0.3 mM). [Na](SL) depletion (vs. [Na](i)) could be as high as 3 mM for [Na](i) approximately 18-20 mM. A simple diffusion model indicates that such [Na](SL) depletion requires a Na diffusion coefficient 10(3)- to 10(4)-fold below that expected in bulk cytoplasm (although this could be subsarcolemmal only). I(pump) integrals and [Na](i) decline were used to estimate intracellular Na buffering, which is slight (1.39 +/- 0.09).
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