Author
Channing R. Robertson
Other affiliations: University of Arizona, University of Virginia, University of Marburg ...read more
Bio: Channing R. Robertson is an academic researcher from Stanford University. The author has contributed to research in topics: Vasa recta & Adsorption. The author has an hindex of 45, co-authored 138 publications receiving 8388 citations. Previous affiliations of Channing R. Robertson include University of Arizona & University of Virginia.
Topics: Vasa recta, Adsorption, Substrate (chemistry), Monolayer, Membrane
Papers published on a yearly basis
Papers
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TL;DR: Techniques which have been used to immobilize whole cells include adsorption, aggregation, confinement and entrapment, and many more have been proposed.
432 citations
TL;DR: Electrostatic repulsion of charged macromolecules by some component of the glomerular capillary wall, perhaps the negatively charged sialoprotein which coats glomersular epithelial cells, might account for the enhanced transmural passage of albumin.
374 citations
TL;DR: A mathematical model developed to investigate the influence of a number of physiological variables on the net driving pressure for ultrafiltration (PuF) in the rat glomerulus indicates that estimates of PUF at the beginning and end of the glomerular capillary bed cannot be used to infer the correct magnitudes of the mean value ofPUF or k in the normal rat.
Abstract: DEEN, W. M., C. R. ROBERTSON, AND B. M. BRENNER. A model of glomerular ultrajltration in the rat. Am. J. Physiol. 223(5) : 1178-l 183. 1972.-A mathematical model has been developed to investigate the influence of a number of physiological variables on the net driving pressure for ultrafiltration (PuF) in the rat glomerulus. The model was used to predict osmotic pressure differences as functions of distance along a glomerular capillary for a wide range of glomerular capillary plasma flow rates, membrane hydraulic permeabilities (k), and axial pressure drops; and these pressure profiles are consistent with recently reported experimental findings. When filtration pressure equilibrium is achieved, results obtained with the model indicate that estimates of PUF at the beginning and end of the glomerular capillary bed cannot be used to infer the correct magnitudes of the mean value of PUF or k in the normal rat. The results also indicate that changes in single-nephron glomerular filtration rate will vary in proportion to changes in plasma flow rate when filtration pressure equilibrium occurs.
343 citations
TL;DR: In this paper, an interfacial stress rheometer has been constructed to study the rheology of Langmuir films subjected to time-dependent flows, where a magnetized rod is set into oscillation by applying a sinusoidal magnetic field gradient and the amplitude and phase of the resulting rod motion relative to the applied force allows the determination of the dynamic surface modulus, Gs*(ω), and measurement of the relative elastic and viscous contributions of the monolayer.
Abstract: An interfacial stress rheometer has been constructed to study the rheology of Langmuir films subjected to time-dependent flows A magnetized rod resides at the air−water interface and is set into oscillation by applying a sinusoidal magnetic field gradient Analysis of the amplitude and phase of the resulting rod motion relative to the applied force allows the determination of the dynamic surface modulus, Gs*(ω), and measurement of the relative elastic and viscous contributions of the monolayer Measurements at 22 °C were conducted on eicosanol (C20) and mixtures of a rigid-rod polymer, phthalocyaninatopolysiloxane (PcPS), dispersed in eicosanol The surface pressure dependence of the rheology for eicosanol reveals the presence of a maximum in the loss modulus, Gs‘ ‘(ω), within the L2‘ phase at Π = 6 mN/m In the LSI phase at pressures above 15 mN/m, the monolayer is Newtonian and has a surface viscosity of 003 mN·s/m The mixtures of PcPS with eicosanol are known to have two-dimensional nematic behavior
323 citations
TL;DR: This sensitivity of fractional dextran clearance to changes in plasma flow indicates that dextrans are transported across the capillary not only by bulk flow but also to an important extent by diffusion.
290 citations
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TL;DR: With the development and increasingly widespread availability of dialysis and transplantation in the past three decades, relatively little attention has been paid to the influence of diet on the progression of renal disease, despite general awareness that renal disease typically follows an inexorably progressive course.
Abstract: IT is now more than 30 years since Addis suggested that protein intake be restricted in patients with chronic renal insufficiency.1 His aim was not to reduce uremic symptoms but rather to prevent a...
2,020 citations
TL;DR: Advances in understanding of the role of molecular weight and architecture on the in vivo behavior of dendrimers, together with recent progress in the design of biodegradable chemistries, has enabled the application of these branched polymers as anti-viral drugs, tissue repair scaffolds, targeted carriers of chemotherapeutics and optical oxygen sensors.
Abstract: Dendrimers are branched, synthetic polymers with layered architectures that show promise in several biomedical applications. By regulating dendrimer synthesis, it is possible to precisely manipulate both their molecular weight and chemical composition, thereby allowing predictable tuning of their biocompatibility and pharmacokinetics. Advances in our understanding of the role of molecular weight and architecture on the in vivo behavior of dendrimers, together with recent progress in the design of biodegradable chemistries, has enabled the application of these branched polymers as anti-viral drugs, tissue repair scaffolds, targeted carriers of chemotherapeutics and optical oxygen sensors. Before such products can reach the market, however, the field must not only address the cost of manufacture and quality control of pharmaceutical-grade materials, but also assess the long-term human and environmental health consequences of dendrimer exposure in vivo.
1,906 citations
TL;DR: In this article, a study was performed in three groups of male Munich-Wistar rats 1 wk after surgery: group I, eight control rats that underwent laparotomy and were fed a normal diet.
Abstract: Micropuncture studies were performed in three groups of male Munich-Wistar rats 1 wk after surgery: group I, eight control rats that underwent laparotomy and were fed a normal diet; group II, nine rats that underwent right nephrectomy and segmental infarction of five-sixths of the left kidney and were fed a normal diet; and group III, seven rats that underwent the same renal ablative procedure and were fed a low protein diet. Single nephron glomerular filtration rate (SNGFR) was higher in the remnant kidney of group II rats compared with group I rats due to higher average values for mean glomerular transcapillary hydraulic pressure difference (delta P) and initial glomerular plasma flow rate (QA) in group II. Glomeruli in remnant kidneys of group II showed striking alterations in morphology, including epithelial cell protein reabsorption droplets, foot process fusion, and mesangial expansion. Group III rats demonstrated a mean SNGFR not statistically different from that of group I, but significantly less than that of group II rats. This lack of absolute hyperfiltration in remnant glomeruli of group III rats relative to group I obtained because QA and delta P did not increase above values found in group I. The glomerular structural lesions seen in group II were also largely attenuated in group III. These studies demonstrate that alterations in glomerular hemodynamics associated with renal ablation are accompanied by structural lesions and suggest that sustained single nephron hyperfiltration may have maladaptive consequences by damaging remnant glomeruli.
1,753 citations
TL;DR: This review integrates recent physiological and molecular understanding of the role of podocytes during the maintenance and failure of the glomerular filtration barrier with hereditary nephrotic syndromes identified over the last 2 years.
Abstract: Glomerular podocytes are highly specialized cells with a complex cytoarchitecture. Their most prominent features are interdigitated foot processes with filtration slits in between. These are bridged by the slit diaphragm, which plays a major role in establishing the selective permeability of the glomerular filtration barrier. Injury to podocytes leads to proteinuria, a hallmark of most glomerular diseases. New technical approaches have led to a considerable increase in our understanding of podocyte biology including protein inventory, composition and arrangement of the cytoskeleton, receptor equipment, and signaling pathways involved in the control of ultrafiltration. Moreover, disturbances of podocyte architecture resulting in the retraction of foot processes and proteinuria appear to be a common theme in the progression of acquired glomerular disease. In hereditary nephrotic syndromes identified over the last 2 years, all mutated gene products were localized in podocytes. This review integrates our recent physiological and molecular understanding of the role of podocytes during the maintenance and failure of the glomerular filtration barrier.
1,358 citations
TL;DR: In this article, the effect of various detoxification methods on the fermentability and chemical composition of lignocellulosic hydrolysates is discussed. But, the main focus of this paper is on the effects of different batch, fed-batch, and continuous fermentation strategies in relation to inhibition of fermentation.
1,320 citations