Revolution and Resistance in the Desert: The Guggenheim System's Impact on Nitrate Mining and Society in Atacama, 1926-31.

In 1926, during an economic crisis that severely impacted the mining industry, Guggenheim Brothers, the Guggenheim family business, implemented a new technological system to extract saltpeter from the Atacama Desert in northern Chile. Known as the Guggenheim system, this cutting-edge technological innovation had a significant impact on regional society and facilitated the introduction of Chilean saltpeter into the global fertilizer market. For this system to succeed, however, it had to incorporate a sociopolitical strategy based on a highly hierarchical and well-controlled labor force. Through their political and cultural influence in the region, the Guggenheim family's industry transformed a remote area into a state periphery, creating new ways of inhabiting the desert within a strict framework in which workers' lives were regulated by company-imposed labor discipline. With more political power than the state, the Guggenheim family sought to suppress any social agency deemed dangerous to the production of saltpeter.

The emerging role of titrimetry in late nineteenth-century industrial problem solving: the example of trace analysis for perchlorate in Chile saltpetre.

Trace analysis is usually associated with high-sensitivity analysis instrumentation. It became fully established from the 1960s following consensus among different groups of practitioners over protocols, reference materials, sensitivity, and accuracy and precision. As a consequence, wet chemical methods have been relegated to a secondary role, contrasting with their tremendous historical significance in detecting, identifying, and estimating small amounts of material. This is particularly relevant to the state-of-the-science analytical determinations stimulated by the effect of minor components in commodities of commercial importance. Here, I select a single example: attempts made during the 1890s to determine the amount of potassium perchlorate (KCIO4) that occurs in Chile saltpetre (sodium nitrate). The application of titrimetry, particularly the adaptation of Volhard's method for chloride analysis, was crucial in the efforts to estimate perchlorate in the nitrate used for explosives and to track the impact of perchlorate concentrations on certain important agricultural crops.

Therapeutic uses of inorganic nitrite and nitrate: from the past to the future.

Potential carcinogenic effects, blue baby syndrome, and occasional intoxications caused by nitrite, as well as the suspected health risks related to fertilizer overuse, contributed to the negative image that inorganic nitrite and nitrate have had for decades. Recent experimental studies related to the molecular interaction between nitrite and heme proteins in blood and tissues, the potential role of nitrite in hypoxic vasodilatation, and an unexpected protective action of nitrite against ischemia/reperfusion injury, however, paint a different picture and have led to a renewed interest in the physiological and pharmacological properties of nitrite and nitrate. The range of effects reported suggests that these simple oxyanions of nitrogen have a much richer profile of biological actions than hitherto assumed, and several efforts are currently underway to investigate possible beneficial effects in the clinical arena. We provide here a brief historical account of the medical uses of nitrite and nitrate over the centuries that may serve as a basis for a careful reassessment of the health implications of their exposure and intake and may inform investigations into their therapeutic potential in the future.

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.

'The heart less bounding': treating angina pectoris.

Although one group of drugs (including amyl nitrite and glyceryl tinitrate) has been used in the treatment of angina for over 100 years, the mode of action became clear only after the endothelium-derived relaxing factor had been identified as nitric oxide in 1987. Originally sodium nitrite was included in this group of drugs but it rapidly fell out of favour. Recently, however, interest in its therapeutic use has been revived. The medical uses of saltpetre (potassium nitrate) may be due to the presence of nitrite as an impurity.

Historical aspects of nitrate therapy.

The exciting story of the development of nitrates as drugs in clinical medicine is briefly reviewed. Glyceryl trinitrate (nitroglycerin) was synthesised by Sombrero in 1847. Amyl nitrite was discovered a few years later and was used by Guthrie in 1859. The first report on the action of glyceryl trinitrate and amyl nitrite was published by Brunton in 1867, and further papers were published by Murell in 1879. Organic nitrates appeared in the 1930s. Krantz and co-workers synthesised and used mannide dinitrate, which was longer acting than the nitrates that had been used previously. Research on a similar drug, isosorbide dinitrate, was initiated by Porjé in Stockholm. The drug was first marketed in Sweden in 1946. Isosorbide dinitrate was independently synthesised in the United States by Harris and colleagues in the 1950s. The drug was used fairly extensively on both sides of the Atlantic. However, there was a temporary decrease in popularity around 1970 when Needleman and colleages reported oral nitrates to be of questionable value, as they underwent rapid biotransformation during first-pass metabolism in the liver. This opinion was later altered and today the drug enjoys worldwide acceptance in different formulations. Also, in recent years one of the active metabolites, isosorbide 5-mononitrate, has been marketed as an effective antianginal drug.

The history of nitrite in human nutrition: a contribution from German cookery books.

In order to settle the question of when saltpetre (nitrate) came in use as an additive to human food, a number of historic cookery books from Germany and Austria were reviewed. Obviously, the change from vegetable dyes to saltpetre for the coloring or color preservation, respectively, of meat occurred between 1600 and 1750, probably near 1700. The addition of sugar which favours the reduction of nitrate to the active agent nitrite became common practice during the 19th century. Thus some historic parallels to the appearance of colorectal cancer, multiple sclerosis and rheumatoid arthritis in the medical literature became apparent.

Baseline nitrate concentration in groundwater of the Chalk in south Dorset, UK.

Determining the degree of nitrate pollution in Chalk groundwater is difficult without a clear understanding of concentrations naturally present. In the UK, a general shortage of long-term records of nitrate concentrations in Chalk groundwater prevents a full quantification of baseline concentrations. This paper presents late nineteenth and early twentieth century data on nitrate concentrations in Chalk groundwater in south Dorset, UK and compares them with corresponding data for the last 25 years. The nitrate record is instructive in (1) providing an insight into the baseline nitrate concentration of groundwater; (2) defining the level of nitrate pollution in potable supplies from the Chalk aquifer; and (3) identifying the long-term variations in local nitrate concentrations. Over a period exceeding 100 years mean nitrate concentrations increased from 1.04 mg NO3-Nl(-1) to 6.37 mg NO3-Nl(-1). Anthropogenic modification of the local groundwater composition is not evident in the early nitrate record. Nitrate data throughout this early period reflect natural background concentrations of approximately 1 mg NO3-Nl(-1). Intensified fertilizer use and increased livestock numbers are suggested as the fundamental cause of the rise in nitrate concentrations. The implications of the nitrate record for regional hydrogeological processes are discussed.

Long-term changes of acidifying deposition in Finland (1973-2000).

The long-term changes of acidifying deposition in Finland during the period 1973-2000 were studied using bulk deposition data from 19 stations belonging to the national monitoring network. The regional-scale approach (southern, central and northern Finland) was used for trend assessment with respect to implementation of European sulphur (S) emission reduction amendments involving deposition changes prior to (1973-1985) and after (1986-2000) the agreements (S protocols in 1985 and 1994). There were no marked changes in sulphate deposition between the 1970s and 1980s and consistent trends in 1973-1985 were not observed. Deposition of nitrogen (N) compounds, particularly NO3-N, were increasing between the 1970s and 1980s. Deposition of base cations exhibited a slight decline throughout the 1970s and 1980s. Decrease of calcium and magnesium deposition without corresponding decrease in sulphate resulted in increased acidifying potential (AP) of deposition. Due to successful implementation of S (and N) emission reduction measures, sulphate deposition has decreased substantially (30% in northern and up to 60% in southern Finland) since the late 1980s. N deposition also decreased, but less than S deposition. Base cation deposition has also declined substantially, but this decline appeared to be leveling off during the 1990s, accounting for the decrease of AP in deposition. The observed deposition pattern is in agreement with the on-going biochemical recovery of acidified small Finnish lakes taking place since the early 1990s.

Use and misuse of nitrogen in agriculture: the German story.

Nitrogen (N) fertilization in agriculture has been discussed controversially in Germany for almost two centuries. The agronomist Carl Sprengel, who published his theory on the mineral nutrition of plants in 1828, advocated the use of mineral N fertilizers. Chemist Justus von Liebig, on the other hand, vehemently denied around 1850 the need for N fertilization. Although it soon became evident that Sprengel was right and Liebig was wrong, not much synthetic N fertilizer was used in German agriculture until around 1915, when the Haber-Bosch technique enabled the commercial production of NH3. The use of N fertilizers since then has grown, especially since 1950. To increase agricultural productivity, German governments have promoted, directly and indirectly, the use of N in crop and in animal production. Unfortunately, it was overlooked that N surpluses in agriculture increased rapidly; around 1980 they amounted yearly to more than 100 kg ha(-1). The extensive use of N in agriculture is causing environmental damage and is contributing substantially to the external costs of present agriculture. The main N compounds that affect the environment are N2O, NH3, and NO3. These compounds are considered to contribute one third to the external costs of agriculture. Additionally, the high rate of human intake of animal proteins and lipids has adversely affected the health of the country's population. Fundamental corrections in German farm policy appear inevitable.

[From Thomas Lauder-Brunton to endogenous nitrates]. / Von Thomas Lauder-Brunton zu den endogenen Nitraten.

While nitrates have been in clinical use for more than 100 years, their mode of action is of rather recent discovery. Nitrates act by the release of the free radical NO (nitric oxide) which stimulates the cyclic guanosine monophosphate as vasodilatator and as inhibitor of platelet function. The endogenous nitrate NO is derived from L-arginine catalyzed by nitric oxide synthase, a recently cloned enzyme. Nitrates and other nitro-vasodilatators act similarly to the endogenous nitrate, whereby a basal release of NO in the vascular wall reduces the effect of nitro-vasodilatators. Therefore, drugs are particularly effective in endothelium-free vessel segments and in veins, where the basal release of NO is low. A recently discovered effect of nitro-vasodilatators is the inhibition of thrombin and angiotensin II-induced production of endothelin. Insofar the L-arginine/NO metabolism acts as an important regulator in the vessel wall and has a protective role in the circulation by its antispastic and antithrombotic principle.

Nitrates and nitrites in the treatment of ischemic cardiac disease.

The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure since the birth of modern pharmacology. Their clinical effectiveness is due to vasodilator activity in large veins and arteries through an as yet unidentified method of delivering nitric oxide (NO), or a NO-like compound. The major drawback is the development of tolerance with NTG, and the duration and route of administration with amyl of nitrite. Although the nitrites are no longer used in the treatment of hypertension or ischemic heart disease, the nitrite anion has recently been discovered to possess novel pharmacologic actions, such as modulating hypoxic vasodilation, and providing cytoprotection in ischemia-reperfusion injury. Although the actions of these 2 similar chemical classes (nitrites and organic nitrates) have often been considered to be alike, we still do not understand their mechanism of action. Finally, the nitrite anion, either from sodium nitrite or an intermediate NTG form, may act as a storage form for NO and provide support for investigating the use of these agents in the treatment of ischemic cardiovascular states. We review what is presently known about the use of nitrates and nitrites including the historical, current, and potential uses of these agents, and their mechanisms of action.

Ação do mononitrato-5 isossorbida sublingual durante cinecoronariografia: comparação com o uso de nitroglicerina sublingual / Sublingual isosorbide-5 mononitrate during coronary arteriography: comparison with sublingual nitroglycerin

OBJETIVO - Avaliar o efeito sublingual do mononitrato-5 de isossobida (MN5IS) e nitroglicerina (NTG) sobre o diâmetro luminal de artérias coronárias epicárdicas, pressão arterial média e efeitos colaterais. MÉTODOS - Cinqüenta pacientes foram submetidos a cateterismo cardíaco e cinecoronariografia, na condição inicial e 5 min após administração sublingual de MN5IS grupo A (GA) ou NTG grupo B (GB). RESULTADOS - O diâmetro coronário de referência aumentou em ambos os grupos, sem significância estatística entre os mesmos. Nos GA e GB foram demosntrados uma diminuição (1,66mmHg) e um aumento (0,79mmHg) na pressão arterial média, respectivamente (p=0,123). Não foram observados efeitos colaterais com o uso destas drogas. CONCLUSÄO - MN5IS sublingual é uma alternativa à administração de NTG durante cinecoronariografia e representa um alternativa terapêutica para o tratamento de doença cardíaca isquêmica.

Nitratos. Um enigma cardiovascular dos anos 90 / Nitrates

Revisao sobre os aspectos historicos e farmacologicos basicos dos nitratos com enfase em suas indicacoes consagradas en estados anginosos e no infartop do miocardio, bem como definicao das principais normatizacoes modernas para a obtencao dos melhores resultados medicos no emprego destes compostos: menor dosagem maior intervalo prescricional e tentativa de reposicao sulfidrica, com selecao individualizada de casos. O futuro do emprego de nitratos em cardiologia deveria compreender o emprego de formulacoes seguras e estaveis.