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BACKGROUND: Malnutrition is a common complication of end-stage liver disease. It is frequently not a priority of treatment before liver transplantation. The purpose of this study was to examine whether prospective preoperative nutritional assessment could predict resource utilization and outcome after liver transplantation. METHODS: We retrospectively reviewed 109 sequential orthotopic liver transplants performed at our center between July 1996 and May 1999. Ten patients with fulminant hepatic failure were excluded from the study, leaving 99 patients. Nutritional status was determined at the time of transplantation using subjective global assessment. Wilcoxon rank sum test and rank analysis of variance were used to analyze the data. Results are reported as median (interquartile range). A P value <0.05 was considered significant. RESULTS: Intraoperative transfusion requirements of packed red blood cells and cryoprecipitate was higher in the patients with severe malnutrition in comparison to the mild and moderate groups (severe vs. moderate, 5.5+/-5.5 vs. 3.0+/-6, P=0.026; vs. mild, 1.5+/-3, P<0.0001). The severe group required more fresh-frozen plasma intraoperatively than the mild group (mild vs. severe, 0+/-2 vs. 2+/-6, P=0.0007; vs. moderate, 1+/-4, P=0.071). Patients in the severe group had longer postoperative lengths of stay compared with patients in the moderate and mild groups (severe vs. moderate, 16+/-9 days vs. 10+/-5 days, P=0.0027; vs. mild, 9+/-8 days, P=0.0006). CONCLUSIONS: Subjective global assessment is an excellent independent predictor of outcome in patients undergoing liver transplantation. Severely malnourished patients require more blood products during surgery and have prolonged postoperative length of stay in hospital. Our data suggest that if nutritional repletion is possible in patients with end-stage liver disease before transplantation, patient outcomes could be improved.
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Trasplante de Hígado , Evaluación Nutricional , Trastornos Nutricionales/diagnóstico , Cuidados Preoperatorios , Transfusión Sanguínea , Femenino , Humanos , Cuidados Intraoperatorios , Tiempo de Internación , Masculino , Persona de Mediana Edad , Trastornos Nutricionales/fisiopatología , Pronóstico , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
Tricarbonyl(eta 5-cyclohexadienyl)iron(0) and dicarbonyl(triphenylphosphine)(eta 5-cyclo-hexadienyl)iron(0) were derivatized by attachment of an aminopropylsilyl link and covalently attached to fumed silica particles. The fumed silica was coated onto the ZnSe element of an attenuated total reflection (ATR) cell for Fourier transform infrared (FTIR) spectroscopic analysis. The immobilized organometalcarbonyl probe groups are shown to retain their capacity to function as a key element of a molecular sensor assembly and the nu(CO) bands of the two probe groups were interrogated to calibrate the responses for 0-5% levels of dodecane in cyclohexanol to within +/- 0.1%. The potential for dual sensing is described and the simultaneous monitoring of two discrete regions of a dynamically varying inhomogeneous system is reported for the determination of dodecane in cyclohexanol as solutions mix across a permeable barrier in the ATR cell.
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A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) in water. The CI-ELISA has a detection limit of 2.3 microg L(-1) and a linear working range of 10--10000 microg L(-1) with an IC(50) value of 195 microg L(-1). The dicamba polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with a dicamba metabolite, 5-hydroxydicamba, and structurally related chlorobenzoic acids. The assay was used to estimate quantitatively dicamba concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, a C(18) (reversed phase) column concentration step was devised prior to analysis, and the detection limits were increased by at least by 10-fold. After the sample preconcentration, the detection limit, IC(50), and linear working range were 0.23, 19.5, and 5-200 microg L(-1), respectively. The CI-ELISA estimations in water correlated well with those from gas chromatography-mass spectrometry (GC-MS) analysis (r(2) = 0.9991). This assay contributes to reducing laboratory costs associated with the conventional GC-MS residue analysis techniques for the quantitation of dicamba in water.
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Dicamba/análisis , Ensayo de Inmunoadsorción Enzimática/métodos , Herbicidas/análisis , Agua/química , Reacciones Cruzadas , Cromatografía de Gases y Espectrometría de Masas , Residuos de Plaguicidas/análisis , Sensibilidad y EspecificidadRESUMEN
PURPOSE: To determine whether fibrin sealant injected into the tract created by liver biopsy can be used to decrease postprocedural bleeding. An innovative delivery system was used to deploy the fibrin sealant. MATERIALS AND METHODS: Fibrin sealant is a hemostatic agent consisting of a suspension of fibrinogen and thrombin. A delivery system was devised whereby fibrin sealant could be injected into the tract created by liver biopsy. Thirty swine were randomized into three groups: control (n = 10), heparin (n = 10), and warfarin (n = 10). Each swine underwent laparotomy and was randomized to undergo three to five open liver biopsies with either a 14-gauge cutting needle in conjunction with the fibrin sealant device or a standard 14-gauge cutting needle alone. Forty-seven biopsy procedures were performed with the device; 64 biopsy procedures were performed without the device. Immediate blood loss per biopsy (mL) was estimated based on the size of the blood stain on a sponge. Specimens were assessed for sample size. RESULTS: Immediate blood loss with and without the device, respectively, was: control, 0.1 mL, 5.4 mL; heparin, 0 mL, 7 mL; warfarin, 0.1 mL, 9.3 mL. These differences were significant (P < .01) for each group of swine. In 43 of 47 biopsies (91%), the device functioned without difficulty. There was no difference in sample size when the device was used. CONCLUSIONS: The fibrin sealant device is effective in reducing bleeding after open liver biopsy in anticoagulated and nonanticoagulated swine. The promising results suggest that a trial of percutaneous liver biopsy in swine should be considered.
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Biopsia con Aguja , Adhesivo de Tejido de Fibrina/uso terapéutico , Hemostáticos/uso terapéutico , Hígado/patología , Animales , Anticoagulantes/uso terapéutico , Biopsia con Aguja/efectos adversos , Biopsia con Aguja/instrumentación , Sistemas de Liberación de Medicamentos , Diseño de Equipo , Adhesivo de Tejido de Fibrina/administración & dosificación , Hemorragia/prevención & control , Hemostáticos/administración & dosificación , Heparina/uso terapéutico , Laparotomía , Agujas , Distribución Aleatoria , Estadísticas no Paramétricas , Porcinos , Jeringas , Warfarina/uso terapéuticoRESUMEN
The actVI genetic region of Streptomyces coelicolor A3(2) is part of the biosynthetic gene cluster of actinorhodin (ACT), the act cluster, consisting of six ORFs: ORFB, ORFA, ORF1, ORF2, ORF3, ORF4. A newly devised method of ACT detection with a combination of HPLC and LC/MS was applied to the analysis of the disruptants of each ORF. ACT was produced by those of ORFB, ORFA, ORF3, and ORF4. Instead of ACT, the ORF1 disruptant produced 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (DMAC) and aloesaponarin II as shunt products. The ORF2 disruptant gave 4-dihydro-9-hydroxy-1-methyl-10-oxo-3-H-naphtho-[2,3-c]-pyran-3-(S)-acet ic acid, (S)-DNPA. These results support our previous proposal for stereospecific pyran ring formation in the biosynthesis of ACT, most importantly suggesting that the actVI-ORF2 product would recognize (S)-DNPA as a substrate for stereospecific reduction at C-15. The disruptant of ORFA produced (S)-DNPA together with ACT, suggesting that actVI-ORFA might play a role such as stabilising the multicomponent, type II PKS complex.
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Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Antraquinonas/análisis , Antraquinonas/metabolismo , Cromatografía Líquida de Alta Presión/métodos , Medios de Cultivo , Regulación Bacteriana de la Expresión Génica , Espectrometría de Masas/métodos , Familia de Multigenes , Mutación , Naftalenos/análisis , Naftalenos/metabolismo , Piranos/análisis , Piranos/metabolismoRESUMEN
A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide glyphosate [N-(phosphonomethyl)glycine] in water. The ELISA has a detection limit of 7.6 microg mL(-1) and a linear working range of 10-1000 microg mL(-1) with an IC(50) value of 154 microg mL(-1). The glyphosate polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with the glyphosate metabolite aminomethylphosphonic acid and a structurally related herbicide, glyphosine [(N,N-bis(phosphonomethyl)glycine]. The assay was used to estimate, quantitatively with accuracy and precision, glyphosate concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, water samples were concentrated prior to analysis, resulting in the increase of the detection limits by 100-fold. After the sample preconcentration step, the detection limit improved to 0.076 microg mL(-1) with an IC(50) value of 1.54 microg mL(-1), and a linear working range was 0.1-10 microg mL(-1). Glyphosate concentrations determined by ELISA correlated well with those determined by high-pressure liquid chromatography (r(2) = 0.99). This assay contributes to reducing the costs associated with conventional residue analysis techniques for the quantitation of glyphosate in water.
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Ensayo de Inmunoadsorción Enzimática , Glicina/análogos & derivados , Herbicidas/análisis , Contaminantes del Agua/análisis , Cromatografía Líquida de Alta Presión , Ensayo de Inmunoadsorción Enzimática/métodos , Glicina/análisis , Humanos , GlifosatoRESUMEN
Conventional cardiopulmonary bypass (CPB) in neonates results in increased transfusion requirements and hemodilution. There has been little advancement in CPB for the neonatal population. There is evidence that increased priming volumes and blood product transfusion enhances inflammatory response to CPB and increases myocardial and pulmonary dysfunction. We have devised a miniaturized CPB circuit that utilizes vacuum-assisted venous drainage (VAVD) in an effort to decrease priming volume and avoid transfusion requirements. The purpose of this study was to evaluate the safety and efficacy of this miniaturized CPB system and determine the feasibility of an asanguineous prime. Ten 1-week-old piglets were randomized to five mini- and five conventional CPB pump circuits. Subjects were supported with CPB at 100 ml/kg/min, cooled to 28 degrees C, exposed to 10 min aortic crossclamp with cardioplegic arrest, rewarmed to 37 degrees C, weaned from bypass, and subjected to modified-ultrafiltration (MUF) for approximately 10 min. This method was chosen to simulate a situation with all the elements of clinical CPB. Blood transfusion trigger was a hematocrit <15 on CPB. Serum samples were obtained pre-CPB, at 15 min of CPB onset, immediately post-CPB completion, and immediately post-MUF. Indices of hemolysis (SGOT, LDH), production of inflammatory mediators (interleukin (IL)-8, tumor necrosis factor-alpha (TNFalpha)), and physiologic parameters of inflammation were measured. The overall blood requirement was significantly less in the mini-circuit compared to conventional CPB (47.0+/-5.8 ml vs 314.2+/-31.6 ml; p < 0.0001). The only significant blood requirement in the mini-circuit was to replace the volume removed for samples. During the study, mean arterial pressure (MAP) (p = 0.004), static pulmonary compliance (p = 0.04), platelets (p = 0.0003), and white blood cells (p = 0.003) significantly decreased across the groups. Lung water content (p = 0.02), TNFalpha levels (p = 0.05), and SGOT (p = 0.009) increased significantly during the study, across the groups. Among all parameters tested, except for blood requirement and hematocrit post-CPB, there were no significant differences between the two circuits. VAVD makes asanguineous prime in neonates feasible. When used in this study to miniaturize a conventional-CPB circuit, VAVD with a reconfigured neonatal CPB console and circuit resulted in no detrimental effects, and allowed for markedly decreased priming volumes and blood transfusion requirements.
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Puente Cardiopulmonar , Circulación Extracorporea/instrumentación , Succión/instrumentación , Animales , Hemodinámica , Inflamación , Sustitutos del Plasma/administración & dosificación , PorcinosRESUMEN
Pyran ring formation in the biosynthesis of actinorhodin in Streptomyces coelicolor A3(2) was studied using the act cluster deficient strain, CH999, carrying pRM5-based plasmids harbouring combinations of the actVI genes. The strain, CH999/pIJ5660 (pRM5 + actVI-ORF1), produced a chiral intermediate, (S)-DNPA, suggesting that the actVI-ORF1 product is a reductase determining the C-3 stereochemical centre.
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Genes Bacterianos , Piranos/química , Streptomyces/genética , Antraquinonas/química , Antraquinonas/metabolismo , Familia de Multigenes , Sistemas de Lectura Abierta , Mapeo RestrictivoRESUMEN
The distribution of nine pesticides between the juice and pulp of carrots and tomatoes during home culinary practices was investigated. Tomato and carrot pulp contained a higher percentage of all pesticide residues, except for mancozeb in tomatoes. Although there was a difference in the relative distribution of the pesticides between the commodities with greater amounts present in the pulp of tomatoes, the pesticides followed a similar trend in both. A relationship between the pulp/juice distribution and water solubility of the pesticide was apparent. Pesticides with the highest water solubility were present to a greater extent in the juice. An exception was noted in the case of diazinon and parathion, which were present in higher amounts in the pulp than their water solubility would suggest. The percent residue in the pulp ranged from 56.4 to 75.2% for carrots, and 49.7 to 95.4% for tomatoes. Residues in the juice prepared from washed commodities ranged from not detected to 0.83 microgram/g. Washing of the produce removed more residue from carrots than from tomatoes, but it did not affect the relative distribution of the residues. The behaviour and fate of the chemical varied with the pesticide as well as the crop.
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Daucus carota/química , Manipulación de Alimentos , Residuos de Plaguicidas/análisis , Solanum lycopersicum/química , Contaminación de Alimentos , Fungicidas Industriales/análisis , Humanos , Insecticidas/análisis , AguaRESUMEN
Derivatives of naringenin have been synthesized with organometalcarbonyl reporting groups for IR spectroscopy attached at C-2, C-3', or C-6, and the products have been tested for the induction of nod gene expression using a Rhizobium leguminosarum strain which contains the Escherichia coli lacZ (beta-galactosidase) gene fused to nodABC. Derivatives with an OMe substituent within the reporting group moiety showed residual gene induction activity.
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Flavonoides/química , Escherichia coli/genética , Flavonoides/farmacología , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Operón Lac , Lipopolisacáridos/metabolismo , Sondas Moleculares , Rhizobium leguminosarum/enzimología , Rhizobium leguminosarum/genética , Espectroscopía Infrarroja por Transformada de Fourier , Activación TranscripcionalRESUMEN
OBJECTIVE: The authors evaluated the response to extended cervicomediastinal thymectomy as a component of the integrated management of patients with myasthenia gravis in a large series of patients from a single institution. The authors evaluated the response to therapy with respect to a graded, multivariate, ordinal scale chosen to reflect the full range of the disease's manifestations. SUMMARY BACKGROUND DATA: A number of series, of varying sizes, describe the response of patients with myasthenia gravis to thymectomy primarily with respect to the bivariate endpoint of the presence or absence of "remission." These studies fail to describe the full spectrum of postoperative disease severity and have been unable to quantify definitively the influence of putative prognostic variables, nor to assess definitively the statistical significance of apparent improvements over time. METHODS: The authors evaluated 202 consecutive patients who underwent trans-sternal thymectomy for symptomatic myasthenia gravis from 1969 through 1996 at the Johns Hopkins Hospital. The response to surgery, combined with postoperative medical therapy, was evaluated by a standardized scale reflecting the full spectrum of the disease. These data were analyzed by a novel mean multivariate regression analysis, which allowed the quantification of the statistical significance of apparent responses over time and the evaluation of the independent influence of each of nine putative prognostic indicators. RESULTS: There was no perioperative mortality and a 33% perioperative morbidity. There was a marked clinical response at 6 months to 1 year after surgery that was sustained for at least 10 years thereafter. The median increment of improvement was two (of five) classes. Eighty-six percent and 83% of the patients had improved by at least one class at 5 and 10 years, respectively. These changes were statistically significant (p < 0.001). Whereas the use of extended cervicomediastinal thymectomy was associated with a greater than twofold chance of improvement, compared to conventional trans-sternal thymectomy, neither the pathologic diagnosis (presence of thymoma) nor the age at surgery proved to be negative predictors of postoperative response. CONCLUSIONS: Extended cervicomediastinal thymectomy is the procedure of choice as a component of the integrated management of myasthenia gravis, with significant improvement seen in the group as a whole, as well as in subgroups of patients with thymoma and those older than 40 years of age.
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Miastenia Gravis/cirugía , Timectomía/métodos , Adolescente , Adulto , Anciano , Niño , Intervalos de Confianza , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Miastenia Gravis/clasificación , Oportunidad Relativa , Pronóstico , Análisis de Regresión , Reoperación , Factores de Riesgo , Infección de la Herida Quirúrgica/etiología , Tasa de Supervivencia , Timectomía/efectos adversos , Timectomía/mortalidad , Resultado del TratamientoRESUMEN
A generalizable, computerized method has been designed to describe in detail interactive events that occur within phases of a process involving two or more interactants. The objectives of the method are: (A) visual discernment of patterns of events within and across phases through graphically displayed data and (B) summarization of events within phases for comparison of events across phases. Stages of the implementation of these objectives are illustrated with data obtained from observations of mother-infant feeding interaction. The method provides a means for an investigator to structure the exploration of patterns of behaviors in the context of the social activity in which the behaviors occur and to develop hypotheses about the data.
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Gráficos por Computador , Conducta Alimentaria , Relaciones Madre-Hijo , Evaluación en Enfermería , Validación de Programas de Computación , Nivel de Alerta , Señales (Psicología) , Femenino , Objetivos , Humanos , Lactante , Recién Nacido , Reproducibilidad de los Resultados , Grabación de Cinta de VideoRESUMEN
Humicola lanuginosa lipase (HIL) and Rhizomucor miehei lipase (RrnL), isolated from commercial preparations of Lipolase and Lipozyme, respectively, were solubilized in AOT-stabilized water-in-oil (w/o) microemulsions in n-heptane and aspects of their hydrolysis and condensation activity examined. The temperature dependence of HIL hydrolysis activity in unbuffered R = 10 microemulsions matched very closely that for tributyrin hydrolysis by Lipolase in an aqueous emulsion assay. Apparent activation energies were measured as 13 +/- 2 and 15 +/- 2 kJ mol / respectively. Condensation activity, however, was essentially independent of temperature over the range 5 degrees to 37 degrees C. The stability of HIL over a 30-day period was very good at all pH levels (6.1, 7.2, 9.3) and R values studied (5, 7.5, 10, 20), except when high pHs and low R values were combined. The excellent stability was reflected by the linearity of the productivity profiles which facilitate system optimization. The temperature dependence of RmL hydrolysis activity toward pNPC(4) showed a maximum at 40 degrees C and an apparent E(act) = 20 +/- 2 kJ mol(-1) was calculated based on the linear region of the profile (5 degrees to 40 degrees C). RmL esterification activity showed only a slight dependence on temperature over the studied range (0 degrees to 40 degrees C) and an apparent E(act) = 5 +/- 1 kJ mol(-1) was measured for octyl decanoate synthesis. Both RmL and HIL, therefore, have potential for application in low temperature biotransformations in microemulsion-based media. The stability of RmL over a 30-day period was good in R = 7.5 and R = 10 microemulsions containing pH 6.1 buffer, and this was reflected in the linearity of their respective productivity profiles. RmL stability was markedly poorer at more alkaline pH, however, and proved to be sensitive to relatively small changes in the R value.
RESUMEN
Gelatin-containing microemulsion based organogels have been used as an immobilisation matrix for lipases from a number of different sources. Kinetic resolutions of octan-3-ol, 1-octen-3-ol and 1-octyn-3-ol by esterification with decanoic acid have been performed using Chromobacterium viscosum (CV) lipase. CV lipase is highly enantioselective in favour of the (R)-(-) isomer of octan-3-ol, but the enantioselectivity is both reversed and decreased by the introduction of unsaturation at the 1-position. Marked improvements in enantioselectivity were achieved by carrying out the reaction at -15 degrees C, the enantiomeric excess of the ester product increasing from 47% (E = 3) to 73% (E = 8) in the case of 1-octen-3-ol, and from 17% (E = 1.4) to 38% (E = 2.5) in the case of 1-octyn-3-ol. The enantiomeric excess was approximately 85% (E approximately 15) for octan-3-ol, and there was no marked improvement in enantioselectivity even at -15 degrees C. Apparent activation energies for the esterification using decanoic acid of octan-3-ol, 1-octen-3-ol and 1-octyn-3-ol by CV lipase were 32 kJ mol-1, 31 kJ mol-1 and 41 kJ mol-1, respectively. This compares to an activation energy of 21 kJ mol-1 for the esterification of octan-1-ol with decanoic acid using CV lipase under the same conditions. Lipases from Pseudomonas (Fluka), Pseudomonas (Genzyme) and lipoprotein lipase ex Microbial (Genzyme) also selectively esterified the (R)-(-) isomer of racemic octan-3-ol, the two Pseudomonas preparations yielding product with an enantiomeric excess of 90%. Candida cylindracea lipase did not exhibit activity in gelatin-containing MBGs. Large-scale syntheses were performed in a 1 dm3 batch reactor in which 200 cm3 of pelleted MBG (containing 350 mg of CV lipase) was used repeatedly for the kinetic resolution of octan-3-ol.
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Candida/enzimología , Chromatiaceae/enzimología , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Lipoproteína Lipasa/metabolismo , Pseudomonas/enzimología , Calorimetría , Emulsiones , Gelatina , Geles , Cinética , Rotación Óptica , Estereoisomerismo , Especificidad por SustratoRESUMEN
Lipolase and Lipozyme are produced in large quantities (as a result of genetic engineering and overexpression) for the detergents market and provide a cheap source of highly active biocatalysts. Humicola lanuginosa lipase (HIL) and Rhizomucor miehei lipase (RmL) have been isolated in partially purified form from commercial preparations of Lipolase and Lipozyme, respectively. These lipases were solubilized in Aerosol-OT (AOT)-stabilized water-in-oil (w/o) microemulsions in n-heptane. HIL and RmL activity in these microemulsions was assayed by spectrophotometric measurement of the initial rate of p-nitophenyl butyrate hydrolysis, and by chromatographic determination of the initial rate of octyl decanoate synthesis from 1-octanol and decanoic acid. The hydrolytic activity of HIL in microemulsions measured as a function of buffer pH prior to dispersal, followed a sigmoidal profile with the highest activities observed at alkaline pHs. This broadly matches the pH-activity profile for tributyrin hydrolysis by Lipolase in an aqueous emulsion assay. The hydrolytic activity of RmL in the same microemulsions, measured as a function of pH, gave a bell-shaped profile with a maximum activity at pH 7.5. Again, the observed pH-activity profile was similar to that reported for a purified RmL in a tributyrin-based aqueous emulsion assay. In contrast, the esterification activity exhibited by both HIL and RmL in AOT microemulsions over the available range pH 6.1 to 10.4, decreases as the pH increases, most likely reflecting the effect of substrate ionization. The dependence of the hydrolytic and condensation activity of HIL on R, the mole ratio of water to surfactant, were similar with both profiles exhibiting a maximum at R = 5. The hydrolytic and esterification activities of RmL followed similar R-dependent profiles, but the profiles in this case exhibited a maximum at R = 10. The water activities at these R values were directly measured as 0.78 and 0.9, respectively. Measured water activities were unperturbed by the presence of lipase at the concentrations used in these studies.
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Five microbial lipases from Chromobacterium viscosum, Candida cylindracea, Pseudomonas (source Fluka), Pseudomonas (source Genzyme) and lipoprotein lipase ex Microbial (Genzyme) have been screened for lactonisation activity towards 16-hydroxyhexadecanoic acid (HHA) in a variety of different w/o microemulsion systems. With the exception of Candida cylindracea (CC), all the lipases exhibited lactonisation activity although they were inherently more active in microemulsion systems based on the anionic surfactant sodium bis(2-ethylhexyl)sulphosuccinate (AOT) than in those based on the cationic surfactant cetyltrimethylammonium bromide (CTAB). Lactone yields are typically 50-60% and are markedly better than those reported previously using microemulsions in combination with chemical catalysts. Lipase stability is superior in the CTAB microemulsion systems, while lipase stability in the low water content AOT microemulsion systems was still good with the exception of CC lipase, which is rapidly inactivated. Buffering the water pools of AOT microemulsions using diglycine buffer at pH 8.0 improved biocatalyst stability. The lactonisation activity of lipases in CTAB w/o microemulsion systems compares favourably with that obtained using the same preparations as a solid suspension in the corresponding water-saturated organic solvent. In addition, the unusual solubility properties of microemulsions allowed the use of considerably higher concentrations of substrate in the microemulsion systems as compared to water-saturated organic solvents such as n-heptane. Lactone yields obtained at equivalent concentrations in the corresponding organic solvents containing conventional condensation catalysts were consistently measured at approx. 10%.
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Lactonas/metabolismo , Lipasa/metabolismo , Ácidos Palmíticos/metabolismo , 4-Aminopiridina/análogos & derivados , Candida/enzimología , Cetrimonio , Compuestos de Cetrimonio , Cromatografía de Gases , Chromobacterium/enzimología , Diciclohexilcarbodiimida , Ácido Dioctil Sulfosuccínico , Emulsiones , Estabilidad de Enzimas , Cinética , Modelos Químicos , Pseudomonas/enzimología , Solubilidad , TensoactivosRESUMEN
Pesticide exposure in greenhouse applicators was measured using the video imaging technique to assess exposure (VITAE) along with dermal patches, air monitoring, and biological assessment techniques. The exposure of five males to pesticides during high- and low-volume application methods in commercial greenhouse operations was evaluated. Failure to use precautionary handling methods when using low-volume applications resulted in the highest level of dermal tracer deposition. Results demonstrated nonuniform deposition of tracer/pesticide mixtures on various body regions, supporting earlier work that questioned the assumption of uniform deposition when assessing exposure with the dermal patch technique. By combining the tracer with an oil-based concentrate, it remained uniformly suspended in the spray solution, and deposition ratios remained constant. Estimates of pirimicarb exposure using the VITAE method were highly correlated with excretion of urinary metabolites (r2 = 0.93). The immediate visual results provided by the VITAE system to applicators proved to be a powerful educational tool in helping them adopt precautionary application techniques. The need to employ protective operating procedures when handling pesticides was demonstrated, no matter how brief the exposure period.
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Agricultura , Monitoreo del Ambiente/métodos , Insecticidas , Exposición Profesional , Pirimidinas , Grabación en Video , Carbamatos , Humanos , Masculino , Nitrilos , Ropa de Protección , PiretrinasAsunto(s)
Chrysanthemum cinerariifolium/crecimiento & desarrollo , Insecticidas/envenenamiento , Exposición Profesional , Fenilcarbamatos , Pirimidinas , Adulto , Anciano , Animales , Carbamatos/envenenamiento , Carbamatos/toxicidad , Recolección de Datos , Endosulfano/envenenamiento , Endosulfano/toxicidad , Femenino , Humanos , Hidrocarburos Clorados/envenenamiento , Hidrocarburos Clorados/toxicidad , Insecticidas/toxicidad , Masculino , Persona de Mediana Edad , Nitrilos , Ontario , Compuestos Organotiofosforados/envenenamiento , Compuestos Organotiofosforados/toxicidad , Control de Plagas , Ropa de Protección/normas , Piretrinas/envenenamiento , Piretrinas/toxicidad , Rayos UltravioletaAsunto(s)
Cumarinas/química , Colorantes Fluorescentes/química , Insecticidas/metabolismo , Ropa de Protección/normas , Pirimidinas , Aluminio/química , Carbamatos/química , Carbamatos/metabolismo , Celulosa/química , Endosulfano/metabolismo , Gossypium/química , Insecticidas/química , Nitrilos , Exposición Profesional , Control de Plagas , Poliésteres/química , Piretrinas/química , Piretrinas/metabolismo , Goma/químicaRESUMEN
Exposure of greenhouse chrysanthemum workers to the pesticide pirimicarb was measured by the Video Imaging Technique to Assess Exposure (VITAE) along with air monitoring and biological assessment techniques. Workers at five commercial chrysanthemum operations were video imaged prior to debudding plants which had been treated with a fluorescent tracer and the pesticide, pirimicarb, 36-48 h earlier. After 1-4 h of debudding, workers were again imaged and the rates of tracer deposition determined with the VITAE system. Tracer deposition from contact with treated foliage was found to increase in a linear fashion over 4 h. Greatest deposition occurred on the hands and arms and represented 42% and 20% of total exposure, respectively. No detectable air residue samples of pirimicarb were found while workers were debudding plants. Monitoring of four workers for pirimicarb and its urinary metabolites revealed no detectable residues following 4 h of contact with foliage, which had been treated 48 h earlier.