Considerações sôbre a técnica de determinação do "Índice Lipásico Seabra"

A detailed study of Seabra's lipasic reagent for the diagnostic of tuberculosis has been made. Substrate. The oily emulsion of cotton seed oil containing gum as dispersing agent, presented a pH variation to the ampoulles examined. In these belonging to the same cartoon as well as in those from different cartoons the values obtained electrometrically ranged from pH 5.8-6.4 (Table I). These variations lead us to presuppose: 1) instability of the oily emulsion in gum; 2) spontaneous hydrolysis of the oil; 3) different batches or technique of the oil extraction, or different sources. Buffer: The same variability observed with substrate was found for the buffer. In CHERRY & CRANDALL's method the buffer is pH 7.0. The saline solution from Seabra's oscillated from pH6.25-6.9 (table II). Titration - end point. A colorimetric comparison between the sample and the blank as suggested by Seabra becomes very difficult. The end point in the presence of serum, when phenolphtalein is used as indicator, is very difficult to compare with the blank containing water. Conclusion. The differences observed in the results when the same serum was used, must be due to the variations observed with Seabra's reagents.

Prevalence of Chlamydia trachomatis in human immunodeficiency virus-infected women in Cuba

To determine the prevalence rates and serovar distribution of Chlamydia trachomatis cervical infections in Cuban women, two different groups were selected. Group I consisted of 60 human immunodeficiency virus (HIV-1) seropositive women from different regions of Cuba and group II of 60 randomly selected women HIV seronegative and apparently healthy. C. trachomatis was detected in cervical scrapes by mean of nested polymerase chain reaction (PCR) specific for major out membrane protein. The overall prevalence rate of C. trachomatis in cervical scrapes determined by nested PCR was 10% in group I and the estimated prevalence was 6.6% for group II; 83.3% of HIV seropositive women with C. trachomatis infection reported history of pelvic inflammatory disease followed by cervicitis (50%). The control group C. trachomatis-infected women referred a history of cervicitis in 75% of cases. Other reports in the latter group included infertility and pelvic inflamatory disease in 50%. The present study is the first report of C. trachomatis prevalence in Cuba. It showed that there was not significantly difference in the prevalence rate of C. trachomatis between both groups.

Steady-state brain glucose transport kinetics re-evaluated with a four-state conformational model.

Glucose supply from blood to brain occurs through facilitative transporter proteins. A near linear relation between brain and plasma glucose has been experimentally determined and described by a reversible model of enzyme kinetics. A conformational four-state exchange model accounting for trans-acceleration and asymmetry of the carrier was included in a recently developed multi-compartmental model of glucose transport. Based on this model, we demonstrate that brain glucose (G(brain)) as function of plasma glucose (G(plasma)) can be described by a single analytical equation namely comprising three kinetic compartments: blood, endothelial cells and brain. Transport was described by four parameters: apparent half saturation constant K(t), apparent maximum rate constant T(max), glucose consumption rate CMR(glc), and the iso-inhibition constant K(ii) that suggests G(brain) as inhibitor of the isomerisation of the unloaded carrier. Previous published data, where G(brain) was quantified as a function of plasma glucose by either biochemical methods or NMR spectroscopy, were used to determine the aforementioned kinetic parameters. Glucose transport was characterized by K(t) ranging from 1.5 to 3.5 mM, T(max)/CMR(glc) from 4.6 to 5.6, and K(ii) from 51 to 149 mM. It was noteworthy that K(t) was on the order of a few mM, as previously determined from the reversible model. The conformational four-state exchange model of glucose transport into the brain includes both efflux and transport inhibition by G(brain), predicting that G(brain) eventually approaches a maximum concentration. However, since K(ii) largely exceeds G(plasma), iso-inhibition is unlikely to be of substantial importance for plasma glucose below 25 mM. As a consequence, the reversible model can account for most experimental observations under euglycaemia and moderate cases of hypo- and hyperglycaemia.

Two-step chromatographic purification of human plasma alpha(1)-acid glycoprotein: its application to the purification of rare phenotype samples of the protein and their study by chromatography on immobilized metal chelate affinity adsorbent.

Alpha1-Acid glycoprotein (AAG) or orosomucoid was purified to homogeneity from human plasma by a separate two-step method using chromatography on immobilized Cibacron Blue F3G-A to cross-linked agarose and chromatography on hydroxyapatite. The conditions for the pre-purification of AAG by chromatography on immobilized Cibacron Blue F3G-A were first optimized using different buffer systems with different pH values. The overall yield of the combined techniques was 80% and ca. 12 mg of AAG were purified from an initial total amount of ca. 15 mg in a ca. 40 ml sample of human plasma. This method was applied to the purification of AAG samples corresponding to the three main phenotypes of the protein (FI*S/A, F1/A and S/A), from individual human plasma previously phenotyped for AAG. A study by isoelectric focusing with carrier ampholytes showed that the microheterogeneity of the purified F1*S/A, F1/A and S/A AAG samples was similar to that of AAG in the corresponding plasma, thus suggesting that no apparent desialylation of the glycoprotein occurred during the purification steps. This method was also applied to the purification of AAG samples corresponding to rare phenotypes of the protein (F1/A*AD, S/A*X0 and F1/A*C1) and the interactions of these variants with immobilized copper(II) ions were then studied at pH 7, by chromatography on an iminodiacetate Sepharose-Cu(II) gel. It was found that the different variants encoded by the first of the two genes coding for AAG in humans (i.e. the F1 and S variants) interacted non-specifically with the immobilized ligand, whereas those encoded by the second gene of AAG (i.e. the A, AD, X0 and C1 variants) strongly bound to immobilized Cu(II) ions. These results suggested that chromatography on an immobilized affinity Cu(II) adsorbent could be helpful to distinguish between the respective products of the two highly polymorphic genes which code for human AAG.

Intracellular thiol-mediated modulation of epithelial sodium channel activity.

The epithelial sodium channel ENaC is physiologically important in the kidney for the regulation of the extracellular fluid volume, and in the lungs for the maintenance of the appropriate airway surface liquid volume that lines the pulmonary epithelium. Besides the regulation of ENaC by hormones, intracellular factors such as Na(+) ions, pH, or Ca(2+) are responsible for fast adaptive responses of ENaC activity to changes in the intracellular milieu. In this study, we show that ENaC is rapidly and reversibly inhibited by internal sulfhydryl-reactive molecules such as methanethiosulfonate derivatives of different sizes, the metal cations Cd(2+) and Zn(2+), or copper(II) phenanthroline, a mild oxidizing agent that promotes the formation of disulfide bonds. At the single channel level, these agents applied intracellularly induce the appearance of long channel closures, suggesting an effect on ENaC gating. The intracellular reducing agent dithiothreitol fully reverses the rundown of ENaC activity in inside-out patches. Our observations suggest that changes in intracellular redox potential modulate ENaC activity and may regulate ENaC-mediated Na(+) transport in epithelia. Finally, substitution experiments reveal that multiple cysteine residues in the amino and carboxyl termini of ENaC subunits are responsible for this thiol-mediated inhibition of ENaC.

Desenvolvimento e aplicação de células eletroquímicas em camada delgada

Theoretical and practical aspects concerning construction and use of a thin layer electrochemical cell are presented. Construction was realized by a simple technic and geometry was optimized in order to minimize the problems of electrical resistance. A well known redox system was studied ((Fe(III)(CN)6(3-)/Fe(II)(CN) 6(4-)) using two experimental methods, cyclic voltammetry and pulse chronopotentiometry. A numerical integration based-program was developed to calculate the voltammetric current in case of nernstian and non-nernstian behaviours and a diffusional model was used to treat the chronopotentiometric data. Thermodynamic (potential, concentration) and kinetic parameters (diffusion coefficient) were successfully determined for the redox system studied in this work.

Síntese e caracterização de alfa-fosfato de zircônio(IV) contendo agregados de cobre metálico

The alpha-zirconium (IV) hydrogenphosphate (alpha-ZrP) has received great attention in the last years due to its properties like ion exchange, intercalation, ionic conductivity and catalytic activity. This work reports a method to produce metallic copper clusters on alpha-ZrP to be used as catalysts in petrochemical processes. It was found that the solids were non-crystalline regardless of the uptake of copper and the reduction. The specific surface area increased as a consequence of the increase of the interlayer distance to accept the copper ions between the layers. During the reduction, big clusters of copper (0,5-11µ) with different sizes and shapes were produced.

Un método de bajo costo para la determinación de cobre a nivel de vestigios en matrices de interés ambiental por espectrofotometría en fase sólida (EFS)

A method for determining copper by solid phase spectrophotometry (SPS) was optimized using the Doehlert design. Copper(II) was sorbed on a styrene-divinylbenzene anion-exchange resin as a Cu(II)-1-(2-pyridylazo)-2-naphthol (PAN) complex, at pH 7.0. Resin phase absorbances at 560 and 800 nm were measured directly. The detection limit was found to be 2.5 µg L-1. The relative standard deviation on ten replicate determinations of 10 µg Cu(II) in 1000 mL samples was 1.1%. The linear range of the determination was 5.0-100 µg L-1. The method was applied successfully to the determination of Cu(II) in natural water and vegetable samples.

Atividade eletrocatalítica de sistemas biomiméticos da enzima catalase

In this work, we describe the immobilization of the dinuclear compound [Cu2(apyhist)2Cl2](ClO4)2 (1) and its derived cations complexes, obtained in water solution or by deprotonation of the imidazolate moiety in the ligand leading to a cyclic tetranuclear species, in the Nafion® membrane on glass carbon electrode surface. After that, we studied the influence of the equilibrium in the electrocatalytic activity towards the reduction of H2O2 in the development of an amperometric sensor for the analytical determination of hydrogen peroxide. This strategy proved successful, and the electrochemical behaviour of the all complexes formed within the Nafion® coatings was characterized. We also provide evidence that its related cyclic tetranuclear imidazolate-bridged complex acts as a catalysts for the intramolecular, two-electron reduction of H2O2.

Flow injection analysis of vancomycin

A flow injection method for the quantitative analysis of vancomycin hydrochloride, C66H75Cl2N9O24.HCl (HVCM), based on the reaction with copper (II) ions, is presented. HVCM forms a lilac-blue complex with copper ions at pH≅4.5 in aqueous solutions, with maximum absorption at 555 nm. The detection limit was estimated to be about 8.5×10-5 mol L-1; the quantitation limit is about 2.5×10-4 mol L-1 and about 30 determinations can be performed in an hour. The accuracy of the method was tested through recovery procedures in presence of four different excipients, in the proportion 1:1 w/w. The results were compared with those obtained with the batch spectrophotometric and with the HPLC methods. Statistical comparison was done using the Student's procedure. Complete agreement was found at a 0.95 significance level between the proposed flow injection and the batch spectrophotometric methods, which present similar precision (RSD: 2.1 % vs. 1.9%).

A relação da caderina-E com o prognóstico do adenocarcinoma colorretal

OBJETIVO: Avaliar a relação da expressão da caderina-E com o intervalo livre de doença (ILD), com a sobrevida (S) e com o estadiamento de doentes operados por adenocarcinoma colorretal. MÉTODO: Foram estudados 89 doentes (41 homens e 48 mulheres) com média de idade de 62,3 anos. A distribuição segundo o estadiamento TNM foi: estádio I - 13 (14,6%) doentes, estádio II - 29 (32,6%), estádio III - 23 (25,8%) e estádio IV - 24 (27,0%). Sessenta e sete doentes foram submetidos à operação radical e acompanhados por um período médio de 37,9 meses. Os tumores foram examinados por técnica imuno-histoquímica e classificados como positivos ou negativos em relação à expressão da caderina-E. RESULTADOS: A caderina-E foi positiva em 49,4% e negativa em 50,6% dos doentes. A recidiva ocorreu em 22,4% dos doentes e não esteve relacionada à expressão da caderina-E. Não foi observada relação da caderina- E com intervalo livre de doença e com a sobrevida. Também não foi verificada a associação da caderina-E (p = 0,958) com o estadiamento TNM. CONCLUSÃO: Os resultados verificados nesta pesquisa não permitem relacionar a expressão tissular da caderina-E com o estadiamento e o prognóstico do adenocarcinoma colorretal.

Indicadores de Prognóstico em Câncer de Mama com Axila Negativa: Receptor de Estrógeno e Expressão de P53 e de c-erbB-2

Objetivo: avaliar o valor prognóstico do receptor de estrógeno e da expressão das proteínas p53 e c-erbB-2 no câncer de mama com axila negativa. Métodos: foi realizado estudo imuno-histoquímico em material incluido em parafina, do arquivo do Instituto de Pesquisas Cito-Oncológicas (IPCO) da Fundação Faculdade Federal de Ciências Médicas de Porto Alegre (FFFCMPA), de 50 casos de câncer de mama sem comprometimento dos linfonodos axilares, em mulheres menopausadas, tratadas na Irmandade da Santa Casa de Porto Alegre (ISCMPA) e no Hospital Santa Rita de Porto Alegre (HSR) de janeiro 1990 a dezembro de 1994. Para análise estatística foram utilizados os testes de c² com correção de Yates, teste exato de Fisher e curvas de sobrevida pelo método de Kaplan-Meier comparados pelo teste log rank. O seguimento médio das pacientes foi de 3,6 anos (3,1-4,5). Dos 50 casos, 14 apresentaram recidiva no período observado. Resultados: a média de idade foi 61 anos (variação de 46 a 78 anos). A mastectomia radical modificada (MRM) foi realizada em 35 pacientes (70%) e 15 (30%) foram submetidas a setorectomia com esvaziamento axilar e posterior radioterapia. Metade das pacientes que apresentaram recidiva apresentaram-na nos três primeiros anos após o diagnóstico. O tamanho médio do tumor foi 2,8 cm (1,98-3,13) e o tipo histológico mais freqüente foi o carcinoma ductal infiltrante de tipo histológico não-especial (92%), conforme a graduação histológica de Bloom e Richardson, sendo 3 grau I (6,6%), 35 grau II (76%) e 8 grau III (17,4%); nos tumores que recidivaram não houve nenhum grau I, 9 (25,7%) eram grau II e 3 (37,5%) eram grau III. Em relação ao prognóstico, a taxa de intervalo livre de doença foi menor quando da associação de tumor pouco diferenciado (grau III) com receptor de estrógeno negativo (p = 0,006), p53 positivo (p = 0,006) e c-erbB-2 positivo (p = 0,001). Conclusão: mulheres menopausadas com câncer de mama sem comprometimento dos linfonodos axilares tem pior prognóstico, em relação ao intervalo livre de doença, quando apresentam associação de tumor pouco diferenciado com RE negativo, p53 positivo e c-erbB-2 positivo.

Resultado da cirurgia com alça de alta freqüência e localização colposcópica da área com atipia ectocervical

Objetivo: avaliar os resultados anatomopatológicos das peças operatórias de pacientes submetidas a cirurgia com alça de alta freqüência e sua relação com a localização colposcópica da atipia. Métodos: estudo retrospectivo de 134 pacientes que apresentavam neoplasia intra-epitelial ao exame citológico e/ou anatomopatológico e que foram submetidas a cirurgia com alça de alta freqüência. As pacientes foram separadas em três grupos, de acordo com a localização das atipias: Grupo I (n = 36): pacientes com atipia localizada na ectocérvice e junção escamo-colunar visível; Grupo II (n = 50): pacientes com atipia ecto-endocervical, e Grupo III (n = 48): pacientes com colposcopia insatisfatória. Resultados: o Grupo I apresentou média de idade de 33, o Grupo II média de 39 e o Grupo III, 48 anos. O comprometimento das margens cirúrgicas por neoplasia ocorreu respectivamente em 8,3, 36 e 29,2% dos casos quando avaliados por grupo. No acompanhamento das pacientes verificou-se que a porcentagem de doença residual foi de 4,2% no Grupo I, 31,6% no Grupo II e 35,5% no Grupo III. Conclusão: pacientes com lesões localizadas no canal endocervical apresentaram maior taxa de margens comprometidas. Pacientes com neoplasia intra-epitelial de alto grau localizadas no canal endocervical e idade superior a 40 anos têm maior chance de apresentar margens comprometidas e doença residual, necessitando de controles citológicos e colposcópicos rigorosos.

Early detection of severe sepsis in the emergency room in adults - Clinical utility of prognostic markers

Vaikean sepsiksen varhainen tunnistaminen päivystyspoliklinikalla – merkkiaineiden käyttökelpoisuus aikuispotilaiden arvioinnissa Päivystyspotilaan vakavan yleisinfektion eli sepsiksen varhainen tunnistaminen ja taudin vaikeusasteen arviointi on päivystävälle lääkärille tärkeä haaste. Arvioimme prospektiivisessa kohorttitutkimuksessa eri merkkiaineiden hyödyllisyyttä sepsiksen varhaisessa tunnistamisessa ja vaikeusasteen arvioinnissa. Työssä I ja III oli 539 päivystyspotilasta, joilta kliinikko päätti ottaa veriviljelyn sepsistä epäillen. Tutkimuksessa II oli 525 potilasta ja tutkimuksessa IV 537 potilasta. Tutkimuksessa I plasman C-reaktiivisen proteiinin (CRP) pitoisuuksia verrattiin plasman prokalsitoniinin (PCT) ja interleukiinin (IL-6) pitoisuuksiin. Tutkimuksessa II verrattiin plasman baktersidisen/ permeabiliteettia lisäävän proteiinin (BPI), ryhmän IIA fosfolipaasi A2:n (PLA2GIIA) ja CRP:n pitoisuuksia sekä valkosolujen määriä toisiinsa. Tutkimuksessa III arvioitiin liukoisen urokinaasi-tyyppisen plasminogeenin aktivaattorireseptorin (suPAR) ja tutkimuksessa IV pentraksiini 3:n (PTX3) määrityksen käyttökelpoisuutta. Tutkimuksessa I todettiin päivystystilanteessa mitattujen korkeiden PCT - ja IL-6 - pitoisuuksien ennustavan vaikean sepsiksen kehittymistä paremmin kuin korkean CRP:n. Tutkimuksessa II plasman PLA2GIIA vaikutti hiukan paremmalta vaikean sepsiksen ennustajalta kuin CRP tai veren valkosolutaso, mutta BPI ei ollut hyödyllinen. Tutkimuksessa III korkea plasman suPAR- pitoisuus osoittautui itsenäiseksi kuolleisuuden riskitekijäksi ja se liittyi myös vaikean sepsiksen kehittymiseen. Tutkimuksessa IV korkea PTX3 - pitoisuus toimi samaan tapaan kuin suPAR. Kokonaisuutena PCT osoittautui parhaaksi merkkiaineeksi ennustamaan elinhäiriön kehittymistä ja suPAR kuolleisuutta. PTX3 ei tarjonnut merkittävää lisäetua PCT:iin ja suPAR:iin verrattuna. CRP osoitti suhteellisen hyvin bakteeri-infektion esiintymistä, mutta ennusteellista arvoa sillä ei ollut. suPAR on kiinnostava kuolleisuuden ja elinhäiriön kehittymisen merkkiaine.

Arsenic and germanium determination by hydride generation in the D.C. plasma optical emission spectrometer

Modifications to the commercial hydride generator, manufactured by Spectrametrics, resulted in improved operating procedure and enhancement of the arsenic and germanium signals. Experiments with arsenic(III) and arsenic(V) showed that identical reiults could be produced from both oxidation states. However, since arsenic(V) is reduced more slowly than arsenic(III), peak areas and not peak heights must be measured when the arsine is immediately stripped from the system (approximately 5 seconds reaction). When the reduction is allowed to proceed for 20 seconds before the arsine is stripped, peak heights may be used. For a 200 ng/mL solution, the relative standard deviation is 2.8% for As(III) and 3.8% for As(V). The detection limit for arsenic using the modified system is 0.50 ng/mL. Studies performed on As(V) standards show that the interferences from 1000 mg/L of nickel(II), cobalt(II), iron(III), copper(II), cadmium(II), and zinc(II) can be eliminated with the aid of 5 M Hel and 3% L-cystine. Conditions for the reduction of germanium to the corresponding hydride were investigated. The effect of different concentrations of HCl on the reduction of germanium to the covalent hydride in aqueous media by means of NaBH 4 solutions was assessed. Results show that the best response is accomplished at a pH of 1.7. The use of buffer solutions was similarly characterized. In both cases, results showed that the element is best reduced when the final pH of the solution after reaction is almost neutral. In addition, a more sensitive method, which includes the use of (NH4)2S208' has been developed. A 20% increase in the germanium signal is registered when compared to the signal achieved with Hel alone. Moreover, under these conditions, reduction of germanium could be accomplished, even when the solution's pH is neutral. For a 100 ng/mL germanium standard the rsd is 3%. The detection limit for germanium in 0.05 M Hel medium (pH 1.7) is 0.10 ng/mL and 0.09 ng/mL when ammonium persulphate is used in conjunction with Hel. Interferences from 1000 mg/L of iron(III), copper(II), cobalt(II), nickel(II), cadmium(II), lead(II), mercury(II), aluminum(III), tin(IV), arsenic(III), arsenic(V) and zinc(II) were studied and characterized. In this regard, the use of (NH4)ZS20S and Hel at a pH of 1.7 proved to be a successful mixture in the sbppression of the interferences caused by iron, copper, aluminum, tin, lead, and arsenic. The method was applied to the determination of germanium in cherts and iron ores. In addition, experiments with tin(IV) showed that a 15% increase in the tin signal can be accomplished in the presence of 1 mL of (NH4)2S20S 10% (m/V).