Caracterização de cálculos renais por análise térmica

Dez amostras de cálculos renais foram estudadas por Análise Elementar de CHN (EA), Espectroscopia de Absorção no Infravermelho (IV) e Difração de raios X pelo método de Pó (XRD). O comportamento térmico das amostras foi estudado por Termogravimetria/Termogravimetria Derivada (TG/DTG) e por Calorimetria Exploratória Diferencial (DSC). Os resultados de EA, Espectroscopia de Absorção IV e XRD mostraram a presença de estruvita [NH4Mg(PO4).6H2O], apatita, oxalato de cálcio monohidratado e oxalato de cálcio dihidratado. As curvas TG e DSC permitiram classificar as amostras em dois grupos diferentes: Grupo I mostrando comportamento térmico típico de estruvita e Grupo II apresentando um perfil termoanalítico característico de mistura de oxalatos.

Cálcio dietético: estratégias para otimizar o consumo

O cálcio é um nutriente essencial necessário em diversas funções biológicas. Estudos têm demonstrado a associação entre o baixo consumo de cálcio e doenças crônicas, entre elas osteoporose, câncer de colón, hipertensão arterial e obesidade. Entretanto, grande parte da população brasileira apresenta consumo de cálcio abaixo do recomendado. Este artigo objetiva revisar os fatores endógenos (idade e estado hormonal) e exógenos (fitatos, oxalatos, sódio, compostos bioativos e vitamina D) que influenciam a absorção do cálcio, bem como as principais metodologias utilizadas para avaliar a absorção e biodisponibilidade desse nutriente. Discorre-se sobre os possíveis fatores para o baixo consumo de cálcio: 1) Hábito alimentar - substituição de leite por bebidas com baixo teor de cálcio como o refrigerante, refeições realizadas fora de casa e a não realização de refeições como o café da manhã; 2) Alto custo dos alimentos fontes de cálcio. Além disso, este artigo discute as estratégias para otimizar o consumo do cálcio, que incluem: 1) Aumentar o conhecimento sobre a importância do consumo de cálcio para a saúde e as principais fontes alimentares desse nutriente; 2) Aumentar a disponibilidade de alimentos fortificados com cálcio; 3) Uso de suplementos em grupos específicos - quando e como administrar os sais de cálcio.

Urolitíase em cães: avaliação quantitativa da composição mineral de 156 urólitos

O estudo teve como objetivo avaliar os casos de urolitíase canina em que a composição mineral dos urólitos foi analisada quantitativamente. Foi avaliada quantitativamente a composição mineral de 156 urólitos obtidos de cães (nefrólitos, ureterólitos, urocistólitos e uretrólitos). Desse total, 79,5% (n=124) eram simples, 18% (n=28) eram compostos e apenas 2,5% (n=4) eram mistos. A estruvita foi o tipo mineral mais frequente nos urólitos simples (47,6%; n=59), em todos os mistos (100%; n=4) e nas camadas núcleo e pedra de urólitos compostos (32,1 e 75%, respectivamente). O oxalato de cálcio foi o segundo mineral mais frequente dos urólitos simples (37,9%, n=47). Ao contrário do que é preconizado para os urólitos simples, as recomendações para o tratamento de urólitos compostos são mais complexas, tais como protocolos de tratamento de dissolução diferentes (se composto por minerais distintos e passíveis de dissolução como urato e estruvita). Além disso, a dissolução pode não ser viável, caso ocorra presença de material insolúvel envolvendo o urólito ou se este representar mais de 20% da camada. Vinte e dois urólitos compostos (78,7%) apresentaram uma camada externa não passível de dissolução (oxalato de cálcio ou fosfato de cálcio); dois (7,1%) apresentaram camadas externas passíveis de dissolução (estruvita ou urato), porém camadas mais internas não solúveis, o que permitiria apenas a dissolução parcial do urólito. Assim, o conhecimento da composição de todas as camadas que compõem o urólito é essencial para o entendimento da formação do cálculo e consequentemente para a indicação do tratamento adequado, assim como para prevenção de recidivas.

Ureteroscopy in Pregnant Women for Ureteral Stone

Introduction: The occurrence of urolithiasis in pregnancy represents a challenge in both diagnosis and treatment of this condition, because it presents risks not only to the mother but also to the fetus. Surgical treatment may be indicated for patients with infection, persistent pain, and obstruction of a solitary kidney. We present our experience on the management of pregnant patients with ureteral calculi and a review of the literature. Materials and Methods: The charts of 19 pregnant patients with obstructive ureteral calculi were retrospectively reviewed. Gestational age ranged from 13 to 33 weeks. In all patients, ureteral stone was diagnosed on abdominal ultrasound. In regard to localization, 15 calculi were in the distal ureter, 3 in the proximal ureter, and 1 in the interior of an ureterocele. Calculi size ranged from 6 to 10 mm (mean, 8 mm). The following criteria were used to indicate ureteroscopy: persistent pain with no improvement after clinical treatment, increase in renal dilation, or presence of uterine contractions. Nine patients (47.3%) were submitted to ureteroscopy. All calculi (100%) were removed with a stone basket extractor under continuous endoscopic vision. None of the calculi demanded the use of a lithotriptor. Results: Nine patients (47.3%) treated with clinical measurements presented no obstetric complications and spontaneous elimination of the calculi. Nine patients (47.3%) submitted to ureteroscopy had no surgical complications. There was remission of pain in all cases after ureteroscopy and ureteral catheter placement. Conclusion: The diagnosis and treatment of ureteral lithiasis in pregnant women present potential risks for the fetus and the mother. Conservative management is the first option, but ureteroscopy may be performed with safety and high success rates.

Relevance of extractives and wood transformation products on the biodegradation of Pinus taeda by Ceriporiopsis subvermispora

Ceriporiopsis subvermispora is a promising white-rot fungus for biopulping. However, the underlying biochemistry involved in lignin removal and insignificant cellulose degradation by this species is not completely understood. This paper addresses this topic focusing on the involvement of ethanol-soluble extractives and wood transformation products in the biodegradation process. Cultures containing ethanol-extracted or in natura wood chips presented similar levels of extracellular enzymes and degradation of wood components. Fe3+-reducing compounds present in undecayed Pinus taeda were rapidly diminished by fungal degradation. Lignin-degradation products released during biodegradation restored part of the Fe3+-reducing activity. However, Fe3+ reduction was ineffective in presence of 0.5 mM oxalate at pH 4.5. Fungal consumption of Fe3+-reducing compounds and secretion of oxalic acid minimized the significance of Fenton`s reaction in the initial stages of wood biotreatment. This would explain limited polysaccharide degradation by the fungus that also lacks a complete set of hydrolytic enzymes. Scientific relevance of the paper: Ceriporiopsis subvermispora is a white-rot fungus suitable for biopulping processes because it degrades lignin selectively and causes significant structural changes on the wood components during the earlier decay stages. However, the intricate mechanism to explain lignin transformation and insignificant cellulose degradation by this species remains poorly understood. Some recent evidences pointed out for lipid peroxidation reactions as all initiating process explaining lignin degradation. On the other hand, alkylitaconic acids produced by the fungus via transformations of fatty acids occurring in wood showed to prevent polysaccharide degradation in Fenton reactions. In this context, one may conclude that the involvement of native wood substances or their transformation products in the overall wood biodegradation process induced by C subvermispora is still a matter of discussion. While free and esterified fatty acids present in wood extractives may be involved in the biosynthesis of alkylitaconic acids and in lipid peroxidation reactions, some extractives and lignin degradation products can reduce Fe3+, providing Fe2+ species needed to form OH radical via Fenton`s reaction. The present study focuses on this topic by evaluating the relevance of ethanol-soluble extractives and wood transformation products on the biodegradation of P. taeda by C subvermispora. For this, solid-state cultures containing ethanol-extracted and in natura wood chips were evaluated in details for up to 4 weeks. (C) 2007 Elsevier Ltd. All rights reserved.

Alkaline-sulfite chemithermomechanical pulping of Eucalyptus grandis biotreated by Ceriporiopsis subvermispora under varied culture conditions

The effect of different culture conditions have been evaluated concerning the extracellular enzyme activities of the white-rot fungus Ceriporiopsis subvermispora growing on Eucalyptus grandis wood. The consequence of the varied fungal pretreatment on a subsequent chemithermomechanical pulping (CTMP) was addressed. In all cultures, manganese peroxidase (MnP) and xylanase were the predominant extracellular enzymes. The biopulping efficiency was evaluated based on the amount of fiber bundles obtained after the first fiberizing step and the fibrillation levels of refined pulps. It was found that the MnP levels in the cultures correlated positively with the biopulping benefits. On the other hand, xylanase and total oxalate levels did not vary significantly. Accordingly, it was not possible to determine whether MnP accomplishes the effect alone or depends on synergic action of other extracellular agents. Pulp strength and fiber size distribution were also evaluated. The average fiber length of CTMP pulps prepared from untreated wood chips was 623 mu m. Analogous values were observed for most of the biopulps; however, significant amounts of shorter fibers were found in the biopulp prepared from wood chips biotreated in cultures supplemented with glucose plus corn-steep liquor. Despite evidence of reduced average fiber length, biopulps prepared from these wood chips presented the highest improvement in tensile indexes (+28% at 23 degrees Schopper-Riegler).

Xylitol production from DEO hydrolysate of corn stover by Pichia stipitis YS-30

Corn stover that had been treated with vapor-phase diethyl oxalate released a mixture of mono- and oligosaccharides consisting mainly of xylose and glucose. Following overliming and neutralization, a d-xylulokinase mutant of Pichia stipitis, FPL-YS30 (xyl3-a dagger 1), converted the stover hydrolysate into xylitol. This research examined the effects of phosphoric or gluconic acids used for neutralization and urea or ammonium sulfate used as nitrogen sources. Phosphoric acid improved color and removal of phenolic compounds. d-Gluconic acid enhanced cell growth. Ammonium sulfate increased cell yield and maximum specific cell growth rate independently of the acid used for neutralization. The highest xylitol yield (0.61 g(xylitol)/g(xylose)) and volumetric productivity (0.18 g(xylitol)/g(xylose) l) were obtained in hydrolysate neutralized with phosphoric acid. However, when urea was the nitrogen source the cell yield was less than half of that obtained with ammonium sulfate.

Effect of pH and oxalic acid on the reduction of Fe(3+) by a biomimetic chelator and on Fe(3+) desorption/adsorption onto wood: Implications for brown-rot decay

Fenton reaction is thought to play an important role in wood degradation by brown-rot fungi. In this context, the effect of oxalic acid and pH on iron reduction by a biomimetic fungal chelator and on the adsorption/desorption of iron to/from wood was investigated. The results presented in this work indicate that at pH 2.0 and 4.5 and in the presence of oxalic acid, the phenolate chelator 2,3-dihydroxybenzoic acid (2,3-DHBA) is capable of reducing ferric iron only when the iron is complexed with oxalate to form Fe mono-oxalate (Fe(C(2)O(4))(+)). Within the pH range tested in this work, this complex formation occurs when the oxalate:Fe(3+) molar ratio is less than 20 (pH 2.0) or less than 10 (pH 4.5). When aqueous ferric iron was passed through a column packed with milled red spruce (Picea rubens) wood equilibrated at pH 2.0 and 4.5. it was observed that ferric iron binds to wood at pH 4.5 but not at pH 2.0, and the bound iron could then be released by application of oxalic acid at pH 4.5. The release of bound iron was dependent on the amount of oxalic acid applied in the column. When the amount of oxalate was at least 20-fold greater than the amount of iron bound to the wood, all bound iron was released. When Fe-oxalate complexes were applied to the milled wood column equilibrated in the pH range of 2-4.5, iron from Fe-oxalate complexes was bound to the wood only when the pH was 3.6 or higher and the oxalate:Fe(3+) molar ratio was less than 10. When 2,3-DHBA was evaluated for its ability to release iron bound to the milled wood, it was found that 2,3-DHBA possessed a greater affinity for ferric iron than the wood as 2,3-DHBA was capable of releasing the ferric iron bound to the wood in the pH range 3.6-5.5. These results further the understanding of the mechanisms employed by brown-rot fungi in wood biodegradation processes. (C) 2009 Elsevier Ltd. All rights reserved.

Study of an alternative phosphate sealer for replacement of hexavalent chromium

This study evaluates the possibility of replacing the hexavalent chromium passivation treatment used as a sealer after phosphating of carbon steel (SAE 1010) by a treatment with niobium ammonium oxalate (Ox). Samples of carbon steel (SAE 1010) after being phosphated in a zinc phosphate bath (PZn + Ni) were immersed in solution of niobium ammonium oxalate (250 mg L(-1) of Nb) either at pH 3.0 or pH 8.0. A passivation treatment with a solution with CrO(3) (200 mg L(-1) of Cr(6+)) was also used for reference. The corrosion resistance of the phosphated samples after passivation treatments was analyzed in a NaCl 0.5 mol L(-1) solution using electrochemical impedance spectroscopy (EIS) and anodic polarization curves. Salt spray tests were also performed to evaluate their corrosion resistance. The results showed that the highest corrosion resistance was obtained by passivation in a solution with (250 mg L(-1) of Nb) at pH 8.0. (C) 2010 Elsevier B.V. All rights reserved.

Morphoanatomic aspects of Psidium guajava L. (Myrtaceae) leaves

Morphoanatomic aspects of Psidium guajava L. (Myrtaceae) leaves. Psidium guajava L. is a perennial shrub, native of tropical America used in Latin American traditional medicine as antimicrobial, antidiarrheic, and in the treatment of diabetes. The morphoanatomical characteristics and histochemistry of the crude drug, whole or powdered, used in pharmaceutical formulations were presented. The main diagnostic characters for the identification of its leaves in the present paper were: venation, trichomes type, number of layers of epidermal cells, mesophyll type and location/type of crystals of calcium oxalate. The morphoanatomical analysis has been proven to be a rapid method for quality control of the crude drug used for medicinal purposes.

Validity of (-)-[H-3]-CGP 12177A as a radioligand for the 'putative beta(4)-adrenoceptor' in rat atrium

1 We have recently suggested the existence in the heart of a 'putative beta(4)-adrenoceptor' based on the cardiostimulant effects of non-conventional partial agonists, compounds that cause cardiostimulant effects at greater concentrations than those required to block beta(1)- and Bz-adrenoceptors. We sought to obtain further evidence by establishing and validating a radioligand binding assay for this receptor with (-)-[H-3]-CGP 12177A ((-)-4-(3-tertiarybutylamino-2-hydroxypropoxy) benzimidazol-2-one) in rat atrium. We investigated (-)-[H-3]-CGP 12177A for this purpose for two reasons, because it is a nonconventional partial agonist and also because it is a hydrophilic radioligand. 2 Increasing concentrations of(-)-[H-3]-CGP 12177A, in the absence or presence of 20 mu M (-)-CGP 12177A to define non-specific binding, resulted in a biphasic saturation isotherm. Low concentrations bound to beta(1)- and beta(2)-adrenoceptors (pK(D) 9.4+/-0.1, B-max 26.9+/-3.1 fmol mg(-1) protein) and higher concentrations bound to the 'putative beta(4)-adrenoceptor' (pK(D) 7.5+/-0.1, B-max 47.7+/-4.9 fmol mg(-1) protein). In other experiments designed to exclude beta(1)- and beta(2)-adrenoceptors, (-)-[H-3]-CGP 12177A (1-200 nM) binding in the presence of 500 nM (-)-propranolol was also saturable (pK(D) 7.6+/-0.1, B-max 50.8+/-7.4 fmol mg(-1) protein). 3 The non-conventional partial agonists (-)-CGP 12177A (pK(i) 7.3+/-0.2), (+/-)-cyanopindolol (pK(i) 7.6+/-0.2), (-)-pindolol (pK(i) 6.6+/-0.1) and (+)-carazolol (pk(i), 7.2+/-0.2) and the antagonist (-)-bupranolol (pK(i) 6.6+/-0.2), all competed for (-)-[H-3]-CGP 12177A binding in the presence of 500 nM (-)-propranolol at the 'putative beta(4)-adrenoceptor', with affinities closely similar to potencies and affinities determined in organ bath studies. 4 The catecholamines competed with (-)-[H-3]-CGP 12177A at the 'putative beta(4)-adrenoceptor' in a stereoselective manner, (-)-noradrenaline (pK(iH) 6.3 +/- 0.3, pK(i), 3.5 +/- 0.1), (-)-adrenaline (pK(iH) 6.5 +/- 0.2, pK(iL) 2.9 +/- 0.1), (-)-isoprenaline (pK(iH) 6.2 +/- 0.5, pK(iL) 3.3 +/- 0.1), (+)-isoprenaline (pK(i) < 1.7), (-)-R0363 ((-)-(1-(3,4-dimethoxyphenethylamino)-3-(3,4-dihydroxyphenoxy)-2-propranol)oxalate, pK(i) 5.5 +/- 0.1). 5 The inclusion of guanosine 5-triphosphate (GTP 0.1 mM) had no effect on binding of (-)-CGP 12177A or (-)-isoprenaline to the 'putative beta(4)-adrenoceptor'. In competition binding studies, (-)-CGP 12177A competed with (-)-[H-3]-CGP 12177A for one receptor state in the absence (pK(i) 7.3 +/- 0.2) or presence of GTP (pK(i) 7.3 +/- 0.2). (-)-Isoprenaline competed with (-)-[H-3]-CGP 12177A for two states in the absence (pK(iH) 6.6 +/- 0.3, pK(iL) 3.5 +/- 0.1; % H 25 +/- 7) or presence of GTP (pK(iH) 6.2 +/- 0.5, pK(iL) 3.4 +/- 0.1; % H 37 +/- 6). In contrast, at beta(1)-adrenoceptors, GTP stabilized the low affinity state of the receptor for (-)-isoprenaline. 6 The specificity of binding to the 'putative beta(4)-adrenoceptor' was tested with compounds active at other receptors. High concentrations of the beta(4)-adrenoceptor agonists, BRL 37344 ((RR + SS)[4-[2-[[2-(3-chlorophenyl)-2-hydroxy -ethyl]amino]propyl]phenoxy]acetic acid, 6 mu M), SR 58611A (ethyl((7S)-7-[(2R)-2-(3-chlorophenyl)-2-hydroxyethylamino]-5,6,7,8-tetrahydronaphtyl-2-yloxy) acetate hydrochloride, 6 mu M), ZD 2079 ((+/-)-1-phenyl-2-(2-4-carboxymethylphenoxy)-ethylamino)ethan-1-ol, 60 mu M), CL 316243 (disodium (R,R)-5-[2-[2-(3-chlorophenyl)-2-hydroxyethyl-amino]propyl]- 1,3-benzodioxole-2,2-dicarboxylate, 60 mu M) and antagonist SR 59230A (3-(2-ethylphenoxy)-1-[(1S)-1,2,3,4-tetrahydronaphth-1-ylamino]-2S-2-propanol oxalate, 6 mu M) caused less than 22% inhibition of (-)-[H-3]-CGP 12177A binding in the presence of 500 nM (-)-propranolol. Histamine (1 mM), atropine (1 mu M), phentolamine (10 mu M), 5-HT(100 mu M) and the 5-HT4 receptor antagonist SE 207710 ((1-butyl-4-piperidinyl)-methyl 8-amino-7-iodo-1 ,4-benzodioxan-5-carboxylate, 10 nM) caused less than 26% inhibition of binding. 7 Non-conventional partial agonists, the antagonist (-)-bupranolol and catecholamines all competed for (-)-[H-3]-CGP 12177A binding in the absence of (-)-propranolol at beta(1)-adrenoceptors, with affinities (pK(i)) ranging from 1.6-3.6 log orders greater than at the 'putative beta(4)-adrenoceptor'. 8 We have established and validated a radioligand binding assay in rat atrium for the 'putative beta(4)-adrenoceptor' which is distinct from beta(1)-, beta(2)- and beta(3)-adrenoceptors. The stereoselective interaction with the catecholamines provides further support for the classification of the receptor as 'putative beta(4)-adrenoceptor'.

Morphology of the thyroid in coastal and noncoastal populations of the koala (Phascolarctos cinereus) in Queensland

The gross morphology, histology, and ultrastructure of the thyroid gland of the koala, Phascolarctos cinereus, is described. Generally, the glands were found to contain large-diameter follicles in association with an epithelium of low height. Morphometric analysis demonstrated a high relative thyroid weight (0.3 +/- 0.2 g/kg) for koalas compared with the 0.07-0.24 g/kg typical of eutherian mammals and 0.03-0.1 g/kg found in other marsupials. The relative thyroid weight of glands (0.33 +/- 0.21 g/kg) from the coastal population (less than 28 km from the coastline) was found to be significantly higher (ANOVA: P = 0.007, significant at the 1% level) than that for glands (0.21 +/- 0.11 g/kg) of noncoastal koalas (greater than 28 km from the coastline). Follicle size was positively correlated (at the 0.1% level) with relative thyroid weight in the overall koala sample. The presence of C cells, occurring singly in the epithelial layer, was demonstrated in electron micrographs. Structural features such as low epithelial height, large follicle length and width, and large intercellular spaces in association with low concentrations of free TS (3.3 +/- 2.1 pM) and free T-3 (1.4 +/- 0.9 pM) as reported previously (Lawson et al., 1996) are consistent with an unusually low level of glandular activity in the koala thyroid even though iodine concentrations in the thyroid gland [4.7 +/- 1.6 mg/g (dry weight)] as well as leaf [0.8 +/- 0.3 mu g (dry weight)] and soil samples [3.8 mu g/g (dry weight)] from the koalas' habitat appear unremarkable. (C) 1998 Academic Press.

Calcium potassium tris(oxalato-O-1, O-2)-chromate(III) pentahydrate

The Cr-III atom in CaK[Cr(C2O4)(3)].5H(2)O, has a regular octahedral geometry with three oxalato groups completing the coordination, Both the calcium and potassium cations are coordinated to the O atom of the oxalate group.

Validação de metodologia analítica para determinação de oxalato na urina

A validação metodológica permite evidenciar se os resultados obtidos por um método são confiáveis, tornando-se um elemento essencial na qualidade. Neste estudo, cujo objectivo é validar a metodologia enzimática para determinação de oxalato na urina, incluíram-se 30 amostras de urina de 24horas, pré-tratadas e estudadas em dois auto-analisadores. Os valores dos limites de detecção e quantificação foram 0,98 e 0,79 mg/L, respectivamente. Para a exactidão obteve-se p=0,713. Na precisão intermédia entre corridas não existem diferenças estatisticamente significativas, em oposição às repetições. Para a linearidade obteve-se r=1 e a sensibilidade foi 0,6%. Conclui-se que o método se mostrou exacto e linear.

Study of thermochemical treatments of cork in the 150-400ºC range using colour analysis and Ftir spectroscopy

A study of chemical transformations of cork during heat treatments was made using colour variation and FTIR analysis. The cork enriched fractions from Quercus cerris bark were subjected to isothermal heating in the temperature range 150–400 ◦C and treatment time from 5 to 90 min. Mass loss ranged from 3% (90 min at 150 ◦C) to 71% (60 min at 350 ◦C). FTIR showed that hemicelluloses were thermally degraded first while suberin remained as the most heat resistant component. The change of CIE-Lab parameters was rapid for low intensity treatments where no significant mass loss occurred (at 150 ◦C L* decreased from the initial 51.5 to 37.3 after 20 min). The decrease in all colour parameters continued with temperature until they remained substantially constant with over 40% mass loss. Modelling of the thermally induced mass loss could be made using colour analysis. This is applicable to monitoring the production of heat expanded insulation agglomerates.