La roca magica: Uses of natural zeolites in agriculture and industry

For nearly 200 years since their discovery in 1756, geologists considered the zeolite minerals to occur as fairly large crystals in the vugs and cavities of basalts and other traprock formations. Here, they were prized by mineral collectors, but their small abundance and polymineralic nature defied commercial exploitation. As the synthetic zeolite (molecular sieve) business began to take hold in the late 1950s, huge beds of zeolite-rich sediments, formed by the alteration of volcanic ash (glass) in lake and marine waters, were discovered in the western United States and elsewhere in the world. These beds were found to contain as much as 95% of a single zeolite; they were generally flat-lying and easily mined by surface methods. The properties of these low-cost natural materials mimicked those of many of their synthetic counterparts, and considerable effort has made since that time to develop applications for them based on their unique adsorption, cation-exchange, dehydration–rehydration, and catalytic properties. Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units. From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future.

Formation of stable cationic lipid/DNA complexes for gene transfer.

Stable cationic lipid/DNA complexes were formed by solubilizing cationic liposomes with 1% octylglucoside and complexing a DNA plasmid with the lipid in the presence of detergent. Removal of the detergent by dialysis yielded a lipid/DNA suspension that was able to transfect tissue culture cells up to 90 days after formation with no loss in activity. Similar levels of gene transfer were obtained by mixing the cationic lipid in a liposome form with DNA just prior to cell addition. However, expression was completely lost 24 hr after mixing. The transfection efficiency of the stable complex in 15% fetal calf serum was 30% of that obtained in the absence of serum, whereas the transient complex was completely inactivated with 2% fetal calf serum. A 90-day stability study comparing various storage conditions showed that the stable complex could be stored frozen or as a suspension at 4 degrees C with no loss in transfection efficiency. Centrifugation of the stable complex produced a pellet that contained approximately 90% of the DNA and 10% of the lipid. Transfection of cells with the resuspended pellet and the supernatant showed that the majority of the transfection activity was in the pellet and all the toxicity was in the supernatant. Formation of a stable cationic lipid/DNA complex has produced a transfection vehicle that can be stored indefinitely, can be concentrated with no loss in transfection efficiency, and the toxicity levels can be greatly reduced when the active complex is isolated from the uncomplexed lipid.

Isolation and characterization of a cell surface albumin-binding protein from vascular endothelial cells.

Albumin-binding proteins identified in vascular endothelial cells have been postulated to contribute to the transport of albumin via a process involving transcytosis. In the present study, we have purified and characterized a 57- to 60-kDa (gp60) putative albumin-binding protein from bovine pulmonary microvessel endothelial cells. The endothelial cell membranes were isolated from cultured cells by differential centrifugation and solubilized with sodium cholate and urea. The solubilized extract was concentrated after dialysis by ethanol precipitation and reextracted with Triton X-100, and the resulting extract was subjected to DEAE-cellulose column chromatography. Proteins eluted from this column were further separated using preparative sodium dodecyl sulfate/polyacrylamide gel electrophoresis and used for immunizing rabbits. Fluorescence-activated cell sorter analysis using the anti-gp60 antibodies demonstrated the expression of gp60 on the endothelial cell surface. Affinity-purified anti-gp60 antibodies inhibited approximately 90% of the specific binding of 125I-labeled albumin to bovine pulmonary microvessel endothelial cell surface. The anti-gp60 antibodies reacted with gp60 from bovine pulmonary artery, bovine pulmonary microvessel, human umbilical vein, and rat lung endothelial cell membranes. Bovine anti-gp60 antibodies also reacted with bovine secreted protein, acidic and rich in cysteine (SPARC). However, bovine SPARC NH2-terminal sequence (1-56 residues) antibodies did not react with gp60, indicating that the endothelial cell-surface-associated albumin-binding protein gp60 was different from the secreted albumin-binding protein SPARC. We conclude that the endothelial cell-surface-associated gp60 mediates the specific binding of native albumin to endothelial cells and thus may regulate the uptake of albumin and its transcytosis.

Intracellular polyamines mediate inward rectification of Ca(2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors.

alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors that lack the glutamate receptor GluR2 subunit are Ca(2+)-permeable and exhibit inwardly rectifying current responses to kainate and AMPA. A proportion of cultured rat hippocampal neurons show similar Ca(2+)-permeable inwardly rectifying AMPA receptor currents. Inward rectification in these neurons was lost with intracellular dialysis and was not present in excised outside-out patches but was maintained in perforated-patch whole-cell recordings, suggesting that a diffusible cytoplasmic factor may be responsible for rectification. Inclusion of the naturally occurring polyamines spermine and spermidine in the recording pipette prevented loss of rectification in both whole-cell and excised-patch recordings; Mg2+ and putrescine were without effect. Inward rectification of Ca(2+)-permeable AMPA receptors may reflect voltage-dependent channel block by intracellular polyamines.

Cell-free activation of neutrophil NADPH oxidase by a phosphatidic acid-regulated protein kinase.

The phosphorylation-dependent mechanisms regulating activation of the human neutrophil respiratory-burst enzyme, NADPH oxidase, have not been elucidated. We have shown that phosphatidic acid (PA) and diacylglycerol (DG), products of phospholipase activation, synergize to activate NADPH oxidase in a cell-free system. We now report that activation by PA plus DG involves protein kinase activity, unlike other cell-free system activators. NADPH oxidase activation by PA plus DG is reduced approximately 70% by several protein kinase inhibitors [1-(5-isoquinolinesulfonyl)piperazine, staurosporine, GF-109203X]. Similarly, depletion of ATP by dialysis reduces PA plus DG-mediated NADPH oxidase activation by approximately 70%. Addition of ATP, but not a nonhydrolyzable ATP analog, to the dialyzed system restores activation levels to normal. In contrast, these treatments have little effect on NADPH oxidase activation by arachidonic acid or SDS plus DG. PA plus DG induces the phosphorylation of a number of endogenous proteins. Phosphorylation is largely mediated by PA, not DG. A predominant substrate is p47-phox, a phosphoprotein component of NADPH oxidase. Phosphorylation of p47-phox precedes activation of NADPH oxidase and is markedly reduced by the protein kinase inhibitors. In contrast, arachidonic acid alone or SDS plus DG is a poor activator of protein phosphorylation in the cell-free system. Thus, PA induces activation of one or more protein kinases that regulate NADPH oxidase activation in a cell-free system. This cell-free system will be useful for identifying a functionally important PA-activated protein kinase(s) and for dissecting the phosphorylation-dependent mechanisms responsible for NADPH oxidase activation.

Inactivation of ethanol-inducible cytochrome P450 and other microsomal P450 isozymes by trans-4-hydroxy-2-nonenal, a major product of membrane lipid peroxidation.

Of the microsomal P450 cytochromes, the ethanol-inducible isoform, P450 2E1, is believed to be predominant in leading to oxidative damage, including the generation of radical species that contribute to lipid peroxidation, and in the reductive beta-scission of lipid hydroperoxides to give hydrocarbons and aldehydes. In the present study, the sensitivity of a series of P450s to trans-4-hydroxy-2-nonenal (HNE), a known toxic product of membrane lipid peroxidation, was determined. After incubation of a purified cytochrome with HNE, the other components of the reconstituted system (NADPH-cytochrome P450 reductase, phosphatidylcholine, and NADPH) were added, and the rate of oxygenation of 1-phenylethanol to yield acetophenone was assayed. Inactivation occurs in a time-dependent and HNE concentration-dependent manner, with P450s 2E1 and 1A1 being the most sensitive, followed by isoforms 1A2, 3A6, and 2B4. At an HNE concentration of 0.24 microM, which was close to the micromolar concentration of the enzyme, four of the isoforms were significantly inhibited, but not P450 2B4. In other experiments, the reductase was shown to be only relatively weakly inactivated by HNE. P450s 2E1 and 2B4 in microsomal membranes from animals induced with acetone or phenobarbital, respectively, are as readily inhibited as the purified forms. Evidence was obtained that the P450 heme is apparently not altered and the sulfur ligand is not displaced, that substrate protects against HNE, and that the inactivation is reversed upon dialysis. Higher levels of reductase or substrate do not restore the activity of inhibited P450 in the catalytic assay. Our results suggest that the observed inhibition of the various P450s is of sufficient magnitude to cause significant changes in the metabolism of foreign compounds such as drugs and chemical carcinogens by the P450 oxygenase system at HNE concentrations that occur in biological membranes. In view of the known activities of P450 2E1 in generating lipid hydroperoxides and in their beta-scission, its inhibition by this product of membrane peroxidation may provide a negative regulatory function.

Fragilidade e qualidade de vida de idosos com doença renal crônica

Introdução: A expectativa de vida dos brasileiros cresce a cada ano; com isso, os idosos vivem mais, e fatores como, Hipertensão Arterial Sistêmica, Diabetes mellitus e o próprio processo de envelhecimento os tornam suscetíveis à doença renal crônica (DRC). Com a DRC, esses idosos têm maiores chances de desenvolverem a fragilidade e terem consequências desfavoráveis na Qualidade de Vida (QV). Objetivo geral: Analisar a relação entre as variáveis independentes (fragilidade, características sociodemográficas e clínicas) e a variável desfecho (QV) de idosos com DRC em tratamento conservador, hemodiálise (HD) e diálise peritoneal (DP). Material e método: Trata-se de uma pesquisa quantitativa, descritiva e transversal. Participaram idosos com 60 anos ou mais, com DRC em tratamento conservador, HD ou DP, que estavam, no mínimo, há seis meses em tratamento e em acompanhamento em um hospital público de Ribeirão Preto-SP. A coleta de dados ocorreu de outubro/14 a março/15, utilizando-se os seguintes instrumentos: de caracterização sociodemográfica, econômica e clínica adaptado; para avaliar a fragilidade, a Edmonton Frail Scale (EFS); para avaliar a QV, o WHOQOL-BREF e WHOQOL-OLD; para avaliar a cognição, o Mini-Exame do Estado Mental (MEEM). Foram realizadas análises estatísticas descritivas, teste de correlação de Spearman e análise de variância multivariada (MANOVA) para as variáveis de interesse. O nível de significância adotado foi de 5%. O projeto foi aprovado por um Comitê de Ética em Pesquisa com seres humanos com CAAE número 34923214.0.0000.5393; seguiu-se as recomendações da Resolução CNS 466/2012. Resultados: Participaram 77 idosos, sendo 35 em tratamento conservador, 14 em DP e 28 em HD. A maioria era homem (41; 53,2%) e tinha companheiro(a) (51; 66,2%). A média dos escores de fragilidade entre os tratamentos foi: tratamento conservador (7,71±3,10); DP (6,79±2,72) e HD (7,36±2,92). No WHOQOL-BREF, os domínios relações sociais e físico obtiveram maior e menor escores médios, respectivamente, (68,93±17,48) e (55,44±14,11). O WHOQOL-OLD apresentou a maior média na faceta Intimidade (68,67±16,45) e menor média na faceta Morte e morrer (37,66±22,76). Foram encontradas correlações inversas entre a idade e o escore do MEEM (p=0,001) e entre anos de estudo e fragilidade (p=0,016); por outro lado, houve correlações positivas entre os escores do MEEM e anos de estudo (p<0,001), entre número de complicações da DRC e fragilidade (p<0,001) e número de comorbidades e fragilidade (p<0,001). Em relação à QV, houve correlação positiva entre o escore global do WHOQOL-BREF e o escore da faceta global do WHOQOL-OLD, bem como correlação inversa entre os escores globais desses instrumentos com os escores de fragilidade (p<0,00; p=0,023). Na MANOVA, o tipo de tratamento e o número de complicações não influenciaram a QV, porém a fragilidade apresentou relação com o constructo, sendo que, para o aumento de um ponto na escala da fragilidade, a QV apresentou redução média de 1,38 no escore global do WHOQOL-BREF e 0,82 no escore global do WHOQOL-OLD, considerando pertencer ao mesmo tipo de tratamento. Conclusão: os pacientes com DRC apresentaram piores escores médios de QV mediante a maiores escores de fragilidade, independentemente do tipo de tratamento e considerando-se a mesma média de complicações

Obtenção e caracterização de PLA reforçado com nanocelulose.

A celulose é o polímero natural renovável disponível em maior abundância atualmente. Por possuir estrutura semicristalina, é possível extrair seus domínios cristalinos através de procedimentos que ataquem sua fase amorfa, como a hidrólise ácida, obtendo-se assim partículas cristalinas chamadas nanopartículas de celulose (NCs). Estas nanopartículas têm atraído enorme interesse científico, uma vez que possuem propriedades mecânicas, como módulo de elasticidade e resistência à tração, semelhantes a várias cargas inorgânicas utilizadas na fabricação de compósitos. Além disso, possuem dimensões nanométricas, o que contribui para menor adição de carga à matriz polimérica, já que possuem maior área de superfície, quando comparadas às cargas micrométricas. Nanocompósitos formados pela adição destas cargas em matrizes poliméricas podem apresentar propriedades comerciais atraentes, como barreira a gases, melhores propriedades térmicas e baixa densidade, quando comparados aos compósitos tradicionais. Como se trata de uma carga com dimensões nanométricas, obtida de fontes renováveis, uma das principais áreas de interesse para aplicação deste reforço é em biopolímeros biodegradáveis. O poli(ácido lático) (PLA), é um exemplo de biopolímero com propriedades mecânicas, térmicas e de processamento superiores a de outros biopolímeros comerciais. No presente trabalho foram obtidas nanopartículas de celulose (NCs), por meio de hidrólise ácida, utilizando-se três métodos distintos, com o objetivo de estudar o método mais eficiente para a obtenção de NCs adequadas à aplicação em compósitos de PLA. Os Métodos I e II empregam extração das NCs por meio do H2SO4, diferenciando-se apenas pela neutralização, a qual envolve diálise ou neutralização com NaHCO3, respectivamente. No Método III a extração das NCs foi realizada com H3PO4. As NCs foram caracterizadas por diferentes técnicas, como difração de raios X (DRX), análise termogravimétrica (TG), espectroscopia vibracional de absorção no infravermelho (FTIR), microscopia eletrônica de transmissão (MET) e microscopia de força atômica (MFA). Os resultados de caracterização das NCs indicaram que, a partir de todos os métodos utilizados, há formação de nanocristais de celulose (NCCs), entretanto, apenas os NCCs obtidos pelos Métodos II e III apresentaram estabilidade térmica suficiente para serem empregados em compósitos preparados por adição da carga no polímero em estado fundido. A incorporação das NCs em matriz de PLA foi realizada em câmara de mistura, com posterior moldagem por prensagem a quente. Compósitos obtidos por adição de NCs obtidas pelo Método II foram caracterizados por calorimetria exploratória diferencial (DSC), análise termogravimétrica, microscopia óptica, análises reológicas e microscopia eletrônica de varredura (MEV). A adição de NCs, extraídas pelo Método II, em matriz de PLA afetou o processo de cristalização do polímero, o qual apresentou maior grau de cristalinidade. Além disso, a adição de 3% em massa de NCs no PLA foi suficiente para alterar seu comportamento reológico. Os resultados reológicos indicaram que a morfologia do compósito é, predominantemente, composta por uma dispersão homogênea e fina da carga na fase matriz. Micrografias obtidas por MEV corroboram os resultados reológicos, mostrando, predominantemente a presença de partículas de NC em escala nanométrica. Compósitos de PLA com NCs obtidas pelo Método III apresentaram aglomerados de partículas de NC em escala micro e milimétrica, ao longo da fase matriz, e não foram extensivamente caracterizados.

Evaluación del bienestar espiritual en pacientes en hemodiálisis

Introducción: Se define la espiritualidad como la búsqueda personal de propósito y significado en la vida, pudiendo incorporar o no la religión. En este artículo se presenta el desarrollo y la aplicación de una medida de bienestar espiritual a una muestra de pacientes en hemodiálisis. Material y métodos: El instrumento básico empleado se denomina Cuestionario del Sentido de la Vida (Meaning in Life Scale, MiLS), con 21 ítems y cuatro escalas: Propósito, Falta de significado, Paz y Beneficios de la espiritualidad. También se proporciona una puntuación global de espiritualidad. Además, se registraron variables de tipo clínico (tiempo en hemodiálisis, índice de comorbilidad de Charlson) y sociodemográfico (edad, género), así como estimaciones del estado de salud, calidad de vida (general y actual), felicidad personal, el grado de religiosidad y la creencia en la existencia de vida ultraterrena. Se ha utilizado un diseño transversal con 94 pacientes en hemodiálisis. Resultados: Los resultados muestran que la versión española de este instrumento (MiLS-Sp) es una medida de bienestar espiritual con garantías psicométricas de calidad (fiabilidad, validez), adecuada para evaluar las complejas exigencias generadas por la problemática de salud del paciente en hemodiálisis. El bienestar espiritual se relaciona significativamente con diversas variables de calidad de vida, percepción de salud, felicidad personal o religiosidad. No existe una relación significativa entre las puntuaciones de espiritualidad y la edad, el sexo, el tiempo en diálisis o el índice de comorbilidad. El grado de bienestar espiritual de estos pacientes es relativamente bajo. Conclusión: La espiritualidad parece desempeñar un papel importante en el bienestar psicológico, el estado de salud y la calidad de vida percibidos por el paciente en hemodiálisis. El grado de bienestar espiritual de estos pacientes es relativamente bajo. Estos resultados sugieren que considerar y evaluar el grado de bienestar espiritual en los pacientes en hemodiálisis puede ser de utilidad para la práctica clínica.

Tratamento conservador da doença renal crónica estadio V : uma abordagem a implementar

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Impaired renal endothelial nitric oxide synthase and reticulocyte production as modulators of hypertension induced by recombinant human erythropoietin in the rat

INTRODUCTION AND AIMS: Hypertension is a common side effect of recombinant human erythropoietin (rHuEPO) therapy; however, the exact pathways remain to be elucidated. The discovery of non-hematopoietic actions of rHuEPO increased the number of patients that could putatively benefit from this therapy; however, to achieve those effects higher doses are usually needed, which increase the risk and incidence of adverse events. Our aim was to study the effect of a broad range of rHuEPO doses on hematological and biochemical parameters, blood pressure and renal function and damage in the rat, focusing on endothelial nitric oxide synthase (eNOS) and hypoxia-inducible factors (HIFs). METHODS: Male Wistar rats were divided in 5 groups receiving different doses of rHuEPO (100, 200, 400 and 600 IU/kg body weight (BW)/week) and saline solution (control), during 3 weeks. Blood and 24h urine were collected to perform hematological and biochemical analysis. Blood pressure (BP) was measured by the tail-cuff method. The kidney tissue was collected to mRNA and protein expression assays and to characterize renal lesions. RESULTS: A dose-dependent increase in red blood cells count, hematocrit and hemoglobin levels was found with rHuEPO therapy, in rHuEPO200, rHuEPO400 and rHuEPO600 groups. Increased reticulocyte count was found in the rHuEPO400 and rHuEPO600 groups. BP raised in all groups receiving rHuEPO. The rHuEPO200 and rHuEPO600 groups presented increased kidney protein levels of HIF2α and a reduction in kidney protein levels of eNOS, along with the highest grade of vascular and tubular renal lesions. CONCLUSIONS: Our study showed that rHuEPO-induced hypertension might involve indirect (hematological) and direct (renal) effects which varies according to the dose used. Thus, rHuEPO therapy should be performed rationally and under adequate surveillance, as hypertension develops even with lower doses. Especial caution with higher doses should be taken, as rHuEPO-induced hypertension leads to early renal damage without alterations in traditional markers of renal function, thus masking the serious adverse effects and risks.

End-stage renal disease annual report to Congress.

No more published?

The feasibility of chronic hemodialysis in California.

Vol. 1 is a synopsis of vol. 2.

Measurement of free drug and clinical end-point by high-performance liquid chromatography-mass spectrometry: Applications and implications for pharmacokinetic and pharmacodynamic studies

Free drug measurement and pharmacodymanic markers provide the opportunity for a better understanding of drug efficacy and toxicity. High-performance liquid chromatography (HPLC)-mass spectrometry (MS) is a powerful analytical technique that could facilitate the measurement of free drug and these markers. Currently, there are very few published methods for the determination of free drug concentrations by HPLC-MS. The development of atmospheric pressure ionisation sources, together with on-line microdialysis or on-line equilibrium dialysis and column switching techniques have reduced sample run times and increased assay efficiency. The availability of such methods will aid in drug development and the clinical use of certain drugs, including anti-convulsants, anti-arrhythmics, immunosuppressants, local anaesthetics, anti-fungals and protease inhibitors. The history of free drug measurement and an overview of the current HPLC-MS applications for these drugs are discussed. Immunosuppressant drugs are used as an example for the application of HPLC-MS in the measurement of drug pharmacodynamics. Potential biomarkers of immunosuppression that could be measured by HPLC-MS include purine nucleoside/nucleotides, drug-protein complexes and phosphorylated peptides. At the proteomic level, two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionisation time-of-flight (TOF) MS is a powerful tool for identifying proteins involved in the response to inflammatory mediators. (C) 2003 Elsevier Science B.V. All rights reserved.

Homocysteine and cardiovascular disease in renal disease

Elevated homocysteine (hyperhomocysteinaemia) in renal patients is a major concern for physicians. Although cause and effect between homocysteine and cardiovascular disease (CVD) has not been established in either the general population or renal patients, there is much evidence that this relationship does exist. Purported mechanisms that may explain this effect include increases in endothelial injury, smooth muscle cell proliferation, low-density lipoprotein oxidation and changes in haemostatic balance. Renal patients have a much greater incidence of hyperhomocysteinaemia and this may be explained by decreases in either the renal or extrarenal metabolism of the compound. We conclude that data from long-term placebo-controlled trials are urgently required to determine whether hyperhomocysteinaemia in renal patients is a cause of CVD events and requires therapeutic targeting.