A Lifetime's Adventure in Extracellular K+ Regulation: The Scottish Connection.

In a career that has spanned 45 years and shows no signs of slowing down, Dr Bruce Ransom has devoted considerable time and energy to studying regulation of interstitial K+. When Bruce commenced his studies in 1969 virtually nothing was known of the functions of glial cells, but Bruce's research contributed to the physiological assignation of function to mammalian astrocytes, namely interstitial K+ buffering. The experiments that I describe in this review concern the response of the membrane potential (Em) of in vivo cat cortical astrocytes to changes in [K+]o, an experimental manoeuvre that was achieved in two different ways. The first involved recording the Em of an astrocyte while the initial aCSF was switched to one with different K+, whereas in the second series of experiments the cortex was stimulated and the response of the astrocyte Em to the K+ released from neighbouring neurons was recorded. The astrocytes responded in a qualitatively predictable manner, but quantitatively the changes were not as predicted by the Nernst equation. Elevations in interstitial K+ are not sustained and K+ returns to baseline rapidly due to the buffering capacity of astrocytes, a phenomenon studied by Bruce, and his son Chris, published 27 years after Bruce's initial publications. Thus, a lifetime spent investigating K+ buffering has seen enormous advances in glial research, from the time cells were identified as 'presumed' glial cells or 'silent cells', to the present day, where glial cells are recognised as contributing to every important physiological brain function.

[Friar José Mariano da Conceição Veloso and the promotion of industrial techniques in colonial Brazil: discussion of some concepts from the chemical sciences]. / Frei José Mariano da Conceição Veloso e a divulgação de técnicas industriais no Brasil colonial: discussão de alguns conceitos das ciências químicas.

At the turn of the 19th century, Minas Gerais Botanist Friar Veloso worked intensely on the publication of books to promote among settlers from the Portuguese empire techniques for improving agricultural production and from the incipient chemistry industry. This article analyzes the first volume of the "Alographia dos alkalis fixos...", a work that includes articles, book chapters, letters and patents from ten authors, particularly French and English, about the scientific and technical knowledge needed for the production of potassium carbonate from the ash of native plants. Some concepts and definitions used at the time of the Chemical Revolution are discussed, considering that Veloso translated them to Portuguese and introduced them to Brazil through his work.

Frei José Mariano da Conceição Veloso e a divulgação de técnicas industriais no Brasil colonial: discussão de alguns conceitos das ciências químicas / Friar José Mariano da Conceição Veloso and the promotion of industrial techniques in colonial Brazil: discussion of some concepts from the chemical sciences

Na virada para o século XIX, o botânico mineiro frei Veloso desenvolveu intensa atividade de publicação de livros com intuito de divulgar aos colonos do império português técnicas para o melhoramento da produção agrícola e da incipiente indústria química. Este artigo aborda o primeiro tomo da Alographia dos alkalis fixos..., obra que contém artigos, capítulos de livros, cartas e patentes coligidos de uma dezena de autores, especialmente franceses e ingleses, sobre o conhecimento científico e técnico necessário para produção de carbonato de potássio a partir de cinza de plantas autóctones. Alguns conceitos e definições da época da Revolução Química são discutidos, levando em conta como Veloso os traduziu para o português e os introduziu no Brasil por meio de sua obra.

At the turn of the 19th century, Minas Gerais Botanist Friar Veloso worked intensely on the publication of books to promote among settlers from the Portuguese empire techniques for improving agricultural production and from the incipient chemistry industry. This article analyzes the first volume of the "Alographia dos alkalis fixos...", a work that includes articles, book chapters, letters and patents from ten authors, particularly French and English, about the scientific and technical knowledge needed for the production of potassium carbonate from the ash of native plants. Some concepts and definitions used at the time of the Chemical Revolution are discussed, considering that Veloso translated them to Portuguese and introduced them to Brazil through his work.

Development of a nondestructive method for underglaze painted tiles--demonstrated by the analysis of Persian objects from the nineteenth century.

The paper presents an analytical method developed for the nondestructive study of nineteenth-century Persian polychrome underglaze painted tiles. As an example, 9 tiles from French and German museum collections were investigated. Before this work was undertaken little was known about the materials used in pottery at that time, although the broad range of colors and shades, together with their brilliant glazes, made these objects stand out when compared with Iranian ceramics of the preceding periods and suggested the use of new pigments, colorants, and glaze compositions. These materials are thought to be related to provenance and as such appropriate criteria for art-historical attribution. The analytical method is based on the combination of different nondestructive spectroscopic techniques using microfocused beams such as proton-induced X-ray emission/proton-induced gamma-ray emission, X-ray fluorescence, 3D X-ray absorption near edge structure, and confocal Raman spectroscopy and also visible spectroscopy. It was established to address the specific difficulties these objects and the technique of underglaze painting raise. The exact definition of the colors observed on the tiles using the Natural Color System helped to attribute them to different colorants. It was possible to establish the presence of Cr- and U-based colorants as new materials in nineteenth-century Persian tilemaking. The difference in glaze composition (Pb, Sn, Na, and K contents) as well as the use of B and Sn were identified as a potential marker for different workshops.

Renal and extrarenal regulation of potassium.

The ISN Forefronts in Nephrology Symposium took place 8-11 September 2005 in Kartause Ittingen, Switzerland. It was dedicated to the memory of Robert W. Berliner, who died at age 86 on 5 February 2002. Dr Berliner contributed in a major way to our understanding of potassium transport in the kidney. Starting in the late 1940s, without knowledge of how potassium was transported across specific nephron segments and depending only on renal clearance methods, he and his able associates provided a still-valid blueprint of the basic transport properties of potassium handling by the kidney. They firmly established that potassium was simultaneously reabsorbed and secreted along the nephron; that variations in secretion in the distal nephron segments play a major role in regulating potassium excretion; and that such secretion is modulated by sodium, acid-base factors, hormones, and diuretics. These conclusions were presented in a memorable Harvey Lecture some forty years ago, and they have remained valid ever since. The concepts have also provided the foundation and stimulation for later work on single nephrons, tubule cells, and transport proteins involved in potassium transport.

Demonstrating trend reversal of groundwater quality in relation to time of recharge determined by 3H/3He.

Recent EU legislation is directed to reverse the upward trends in the concentrations of agricultural pollutants in groundwater. However, uncertainty of the groundwater travel time towards the screens of the groundwater quality monitoring networks complicates the demonstration of trend reversal. We investigated whether trend reversal can be demonstrated by relating concentrations of pollutants in groundwater to the time of recharge, instead of the time of sampling. To do so, we used the travel time to monitoring screens in sandy agricultural areas in the Netherlands, determined by (3)H/(3)He groundwater dating. We observed that concentrations of conservative pollutants increased in groundwater recharged before 1985 and decreased after 1990. Thereby, we demonstrated trend reversal of groundwater quality. From this research we concluded that (3)H/(3)He dating can be used to facilitate (re)interpretation of existing groundwater quality data. The presented approach is widely applicable in areas with unconsolidated granular aquifers and large agricultural pressures on groundwater resources.

Glucose-insulin-potassium techniques in cardiac surgery: historical overview and future perspectives.

Since the days of the first cardiac surgical operations in the previous century, myocardial preservation has been an essential component of the successful outcome of these procedures. Although many different techniques to achieve myocardial preservation and modulation have been described in the past 50 years, this review focuses on the use of glucose, insulin, and potassium (GIK) and its effect on ischemic and postischemic myocardium.

Milestones in nephrology: Presence of luminal K+, a prerequisite for active NaCl transport in the cortical thick ascending limb of Henle's loop of rabbit kidney.

Originally published in Pflügers Arch. 392:92-94, 1981. Reprinted with author commentary by Dr. Schlatter.

Myocardial protection: the rebirth of potassium-based cardioplegia.

The introduction of open-heart surgery more than 4 decades ago signaled a new era in medicine. For the 1st time, previously untreatable cardiac anomalies became amenable to surgical therapy. The use of the heart-lung machine seemed to grant the surgeon unlimited time in which to operate inside the heart. Still frustrated by poor operating conditions and the threat of air embolism, Denis Melrose introduced elective cardiac arrest in 1955. His use of a potassium citrate solution seemed to offer a safe method to effect a quiet, bloodless field. However, a few years after its inception, numerous reports began to question the safety of this approach, and the Melrose technique was abandoned in the early 1960s. Nearly 15 years elapsed before potassium-based cardioplegia regained popularity. During this period, topical hypothermia, coronary perfusion with intermittent aortic occlusion, and normothermic ischemia were evaluated and discarded. A few European investigators like Hoelscher, Bretschneider, and Kirsch had maintained their interest in chemical cardioplegia, and it was through their efforts that future researchers like Hearse and Gay spearheaded the return to potassium-based cardioplegia, which today forms the core of the cardiac surgeon's myocardial protective armamentarium and has contributed towards lowering operative mortality rates.

Potassium-induced cardioplegia: evolution and present status.

Most cardiac surgical procedures performed in 1989 are accomplished with the aid of some type of controlled, chemically induced cardiac standstill. Although the physiological principles involved were described in the late 19th century, the first clinical application was not until 1955. Because many surgeons believed that myocardial injury resulted from the toxicity of the agents used, the technique was largely abandoned for about 15 years. With the increasing volume of coronary revascularization surgery and with the need for protection of donor hearts intended for orthotopic transplantation, chemically induced cardiac standstill became more appealing and the technique was revived and reevaluated in several centers. In the last several years, the constitution of cardioplegic solutions and the methods by which they are delivered have been greatly modified. Although the most effective solution and technique may yet remain to be described, unquestionably controlled chemically induced cardiac standstill has contributed substantially to the ease and safety with which cardiac surgical procedures can be accomplished. This vignette, although far from complete, outlines some of the important works that have contributed to the evolution of cardioplegic techniques.