[Experiences of a pediatric nurse in a premature intensive care unit. Emphasis in the nursing of premature infants with respiratory distress syndrome].
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Humans↗
Biomedical subjects
R Zeh
Publications and source records attributed to R Zeh.
Desensitization of the bradykinin-induced rise in intracellular free calcium in cultured endothelial cells.
We studied the cellular mechanism involved in the desensitization of cultured endothelial cells to bradykinin. Bradykinin (10 nmol/l) evoked a rise in the intracellular free calcium concentration [( Cai2+]), measured with the fluorescent probe indo-1, from 137 +/- 30 (+/- SEM) to 623 +/- 101 nmol/l. Cells were desensitized to bradykinin by repetitive stimulation with the peptide over 10 min, after which they no longer responded to bradykinin. However, purinergic stimulation with ATP (10 mumol/l) elicited the same increase in [Cai2+] in endothelial cells desensitized to bradykinin as in cells never exposed to bradykinin. The initial peak of [Cai2+] after stimulation with bradykinin or ATP was not affected by removal of extracellular calcium ions, indicating mobilization of Ca2+ from intracellular stores. Since GTP-binding proteins (G-proteins) are probably involved in the receptor-mediated stimulation of endothelial cells, we also tested the effects of sodium fluoride (NaF), a reported direct stimulator of G-proteins, on endothelial [Cai2+]. NaF (5 mmol/l) increased [Cai2+] to 412 +/- 88 nmol/l in control cells and was equally effective in cells desensitized to bradykinin. We conclude that the homologous desensitization to bradykinin does not occur at the level of intracellular signal transduction but at the level of membrane receptors.
Adenosine Triphosphate↗
Phase-randomized laser illumination for microscopy.
A simple apparatus is described that phase randomizes the output of a continuous argon ion laser, so that it may be used as a source of high intensity, monochromatic light for microscopy. The phase-randomizing device can be used with any laser, polarized or unpolarized, and of any desired power output and wavelength, including dye lasers for spectral studies. The randomizing system can be adapted to any light microscope and any optical system including bright-field, phase-contrast, Nomarski differential-interference, dark-field, and split-beam interference systems such as the Jamin-Lebedeff System. It can be used for a variety of photometric and photographic studies. The 514-nm wavelength appears to be relatively harmless to a variety of cells.
Lasers↗
Evaluation of driving-while-intoxicated programs; some methodological considerations.
Some methodological problems encountered in evaluating the effectiveness of driving-while-intoxicated programs are discussed.
Accidents, Traffic↗
Direct test of the positive pressure gradient theory of pseudopod extension and retraction in amoebae.
When one pseudopod of an amoeba is sucked into a capillary connected to a partial vacuum and subjected to a pressure reduction of 30 to 35 centimeters of water, extension of other pseudopods, exposed to atmospheric pressure, is not prevented. This result is interpreted to mean that cytoplasmic streaming cannot be the result of a positive pressure gradient generated along the length of the stream, for if it were, streaming would have reversed its direction under the applied pressure gradient of opposite sign and supposedly greater magnitude.
Amoeba↗