Xpert MTB/RIF Ultra CT value provides a rapid measure of sputum bacillary burden and predicts smear status in patients with pulmonary tuberculosis.

Traditionally, smear microscopy has been used to estimate bacillary burden in order to assess infectiousness in tuberculosis (TB) patients. Since Xpert MTB assays might replace smear microscopy as the first-line diagnostic test for pulmonary tuberculosis, an alternative measure of bacillary load that correlates with smear positivity is needed. This study assessed the correlation between CT (with and without normalization), smear status, culture time-to-positivity (TTP), and clinical factors in patients with Xpert ultra positive sputum during a four-year period. A cut-off CT value for smear positivity was also estimated. 204 samples were included. Strong correlation between both Xpert Ultra CT values (raw and normalized) and smear status was obtained (r = 0.78 and - 0.79, respectively). The association between Raw-CT and TTP was weaker than normalized-CT (N-CT) and TTP (r = 0.50 and r = - 0.70, respectively). A Raw-CT cut-off value of 21.4 was identified with 85.7% (95% CI 65.4-95) sensitivity and 92.9% (95% CI 84.3-96.9) specificity. A N-CT cut-off value of 5.2 yielded a sensitivity of 94.3% (95% CI 86.2-97.8) and specificity of 85.7% (95% CI 65.4-95). Our study demonstrates that Xpert Ultra CT value correlates well with other measures of bacillary load such as smear status or TTP. The correlation with TTP is stronger when the CT value is normalized using the internal control. The proposed N-CT cut-off value of 5.2 shows a better sensitivity than the Raw-CT when predicting smear positive status.

Clinical Effectiveness of SARS-CoV-2 Vaccination in Renal Transplant Recipients. Antibody Levels Impact in Pneumonia and Death.

BACKGROUND: Few studies have described the clinical impact of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in renal transplant recipients (RTRs) in the context of omicron variant and the third vaccine dose. Antibody titer has been tried to relate to the prediction of outcomes related to SARS-CoV-2, but it results controversially in these populations. METHODS: All patients with positive SARS-CoV-2 polymerase chain reaction followed at a RTRs reference center from March 15, 2020, to March 15, 2022, were considered for analysis. Cases were analyzed by vaccination status. Breakthrough cases were then analyzed by nonantibodies (<20 arbitrary unit [AU]/mL), low (20-100 AU/mL), and high antibody titers (>100 AU/mL) against SARS-CoV-2 spike protein. Outcomes included pneumonia and mortality. We used logistic regression multivariable to assess for confounders. RESULTS: Among 186 RTRs with coronavirus disease 2019, 50.5% (n = 94) were vaccinated versus 49.5% (n = 92) unvaccinated. Of the vaccinated patients, 67.02% developed a high antibody titer (>100 AU/mL) but 14.89% achieved a low antibody titer and 18.08% nonantibodies. Pneumonia-free survival (day 20) was 95% in high antibody titer but 40% in unvaccinated RTRs. Survival in RTRs at day 60 was similar in the unvaccinated group compared with nonantibodies breakthrough cases (82%) but 92% in the low antibody titer group (relative risk, 0.027; 95% confidence interval, 0.002-0.479; P = 0.014). Only patients with >100 AU/mL showed a 100% survival on day 60 postinfection. CONCLUSIONS: Vaccinated RTRs who achieve at least a low antibody titer (>20 AU/mL) had better results in terms of pneumonia and mortality than unvaccinated RTRs. Antibody titer >100 AU/mL associate with even better results than patients with lower antibody titers.

Prevalence of eosinophilic esophagitis: A multicenter study on a pediatric population evaluated at thirty-six Latin American gastroenterology centers. / Prevalencia de esofagitis eosinofílica: estudio multicéntrico en población pediátrica evaluada en 36 centros de gastroenterología de América Latina.

INTRODUCTION AND OBJECTIVE: Eosinophilic esophagitis is a chronic, immune-mediated disease described in case series and publications worldwide. Over the past twenty years, the authors of different studies have attempted to evaluate its incidence and prevalence. The objetive of the present study was to estimate the prevalence of eosinophilic esophagitis in a group of children seen at 36 pediatric gastroenterology centers in ten Latin American countries. MATERIALS AND METHODS: A multicenter, observational, and cross-sectional study was conducted that estimated the period prevalence of eosinophilic esophagitis in children seen at outpatient consultation and that underwent diagnostic upper gastrointestinal endoscopy for any indication at 36 centers in 10 Latin American countries, within a 3-month time frame. RESULTS: Between April and June 2016, 108 cases of eosinophilic esophagitis were evaluated. Likewise, an average of 29,253 outpatient consultations and 4,152 diagnostic upper gastrointestinal endoscopies were carried out at the 36 participating centers. The period prevalence of eosinophilic esophagitis in the population studied (n=29,253) was 3.69 cases×1,000 (95% CI: 3.04 to 4.44), and among the children that underwent routine upper gastrointestinal endoscopy (n=4,152), it was 26x1,000 (95% CI: 22.6 to 29.4). CONCLUSIONS: The general period prevalence of eosinophilic esophagitis in a group of children evaluated at 36 Latin American pediatric gastroenterology centers was 3.69×1,000, and in the children that underwent endoscopy, it was 26×1,000. There was important prevalence variability between the participating countries and centers. The present analysis is the first study conducted on the prevalence of pediatric eosinophilic esophagitis in Latin America.

Fetal intracranial immature teratoma: presentation of a case and a systematic review of the literature.

OBJECTIVES: To describe a case diagnosed with intracranial teratoma in week 32 of gestation, as well as review of the literature in order to discern the appropriate treatment method and general prognosis of this anomaly. METHODS: A literature search was performed on the prenatal diagnosis of congenital intracranial teratomas in MEDLINE, EMBASE, Cochrane library data bases. Evaluated in this review are parameters such as time of prenatal diagnosis, associated pathology, size of tumors, method of terminating pregnancy, perinatal outcome and histological study of the tumor. RESULTS: A total of 49 cases were found, of which 12 were finished gestation, 28 cesarean section was performed and only nine had vaginal delivery. All died in the neonatal period except in three cases with intrauterine death after diagnosis. CONCLUSION: As the incidence of intracranial immature teratomas is very low and the prognosis is poor, their prenatal diagnosis and obstetric management present a great challenge for the planning of a follow-up and treatment of the disease in accordance with the preferences of the parents.

Presence of T-275A and C-2152T Polymorphisms of the Promoter Region of Uridine Diphosphate-Glucuronosyltransferase 1A9 Increases Mortality From Digestive Tumors: Results After 10 Years of Follow-up in a Renal Transplant Population.

BACKGROUND: The aim of this study was to determine the distribution of uridine diphosphate-glucuronosyltransferase 1A9 (UGT1A9) promoter region T-275A and C-2152T single-nucleotide polymorphisms (SNPs) in stable transplant patients and to investigate the impact of these SNPs on the evolution of this population after 10 years of follow-up. METHODS: White renal transplant recipients (n = 873) were studied. The median time of follow-up was 91.8 months (P25-75 46-146). Amplification with specific "primers" to delimit the study area was performed for each polymorphism. Amplification was performed with the use of real-time polymerase chain reaction. RESULTS: T-275A promoter mutation was detected in 13% of patients and C-2152T in 12% of patients. Survival analysis was performed on 873 renal transplants, carried out between 2004 and 2013. We found a higher frequency of death from cancer among polymorphism carriers (P = .001). CONCLUSIONS: It appears that carriers of T-275A and C-2152T SNPs of the UGT1A9 gene promoter region show a greater incidence of death from cancer, with a significantly higher cumulative incidence of death from gastrointestinal tumors.

Embarazo en mujeres en diálisis crónica: revisión / Pregnancy in women on chronic dialysis: a review

La frecuencia de embarazos en mujeres en diálisis es extremadamente baja, aunque el porcentaje de gestaciones con éxito ha aumentado a lo largo de los años, siendo, según distintas series, superior al 70%. Estos embarazos no están exentos de complicaciones tanto para la madre como para el feto, el manejo de las cuales requiere el trabajo conjunto del nefrólogo, el ginecólogo, el enfermero y el nutricionista. A día de hoy no es posible encontrar un tratamiento sistemático nefrológico y ginecológico en este tipo de pacientes. Las principales medidas que se deberían adoptar incluirían: aumento del tiempo de diálisis, mantener bajos niveles de urea prediálisis, evitar hipotensiones e hipertensión materna, así como infecciones urinarias y fluctuaciones electrolíticas. Se requiere, además, una adecuada monitorización fetal (AU)

The frequency of pregnancy in women on dialysis is extremely low, but the percentage of successful pregnancies in this context has increased over the years, with some studies placing the survival rate above 70%. These pregnancies are not exempt from both maternal and foetal complications, and so their management requires the joint efforts of nephrologists, gynaecologists, nurses, and nutritionists. Currently, we have been unable to establish consistent systematic treatment from both nephrological and gynaecological specialists in these patients. The main changes that need to be made are: increased time on dialysis, maintaining low levels of pre-dialysis urea, avoiding: maternal hypertension and hypotension, anaemia, urinary tract infections, and fluctuations in electrolytes. Adequate foetal monitoring is also necessary (AU)

Pregnancy in women on chronic dialysis: a review.

The frequency of pregnancy in women on dialysis is extremely low, but the percentage of successful pregnancies in this context has increased over the years, with some studies placing the survival rate above 70%. These pregnancies are not exempt from both maternal and foetal complications, and so their management requires the joint efforts of nephrologists, gynaecologists, nurses, and nutritionists. Currently, we have been unable to establish consistent systematic treatment from both nephrological and gynaecological specialists in these patients. The main changes that need to be made are: increased time on dialysis, maintaining low levels of pre-dialysis urea, avoiding: maternal hypertension and hypotension, anaemia, urinary tract infections, and fluctuations in electrolytes. Adequate foetal monitoring is also necessary.

Phenology and attraction of potential Culicoides vectors of bluetongue virus in Basque Country (northern Spain).

Bluetongue virus is transmitted by Culicoides biting midges (Diptera: Ceratopogonidae). Culicoides associated with livestock were captured using CDC blacklight traps at three BTV-infected farms in Basque Country between November 2007 and December 2008. Twenty-seven and nineteen Culicoides species were collected in outdoor and indoor habitats respectively. Indoor insect community represented 86.1% of the whole captured individual biting midges. Culicoides obsoletus/Culicoides scoticus (two sibling species of the Obsoletus complex) were dominant throughout all months and sexes with maximum phenological peaks in November 2007 and June-July 2008. Culicoides lupicaris was the second most dominant species followed by Culicoides pulicaris (both species of the Pulicaris complex). Few specimens of Culicoides imicola, the principal Afro-Mediterranean vector of BTV, as well as four new species recorded for the Iberian Peninsula, were also collected. BTV was detected by RT-PCR from pools of C. obsoletus/C. scoticus, C. lupicaris and C. pulicaris parous females. DL-Lactic acid significantly attracted more C. obsoletus/C. scoticus females and males, C. lupicaris females, C. pulicaris females and Culicoides punctatus females and males; whereas acetone increased only the captures of Culicoides achrayi.

Identificación de compuestos volatiles, aminoácidos libres por cromatografía y las propiedades sensoriales de los quesos de pasta hilada conocido como momposino / Identification of volatile compounds, free amino acids through chromatography and sensory properties of the pasta filata cheeses known as momposino

El queso Momposino es una variedad de queso de pasta hilada que se encuentra comúnmente en Colombia. Para esta investigación fueron identificadas varias tecnologías de producción de queso de la siguiente manera: técnicas 1 y 2, para quesos elaborados de leche cruda (tales como quesos autóctonos), técnica 3, para quesos hechos con leche pasteurizada y con un cultivo; y técnica 4, para quesos hechos con leche cruda. Los compuestos volátiles y aminoácidos libres fueron examinados por cromatografía y la evaluación sensorial desempeñada por los miembros del laboratorio. Los quesos hechos con las técnicas 1 y 2 presentaron más compuestos volátiles (con 60 y 73 respectivamente) que los quesos hechos con la técnica 3 (para el cual 52 compuestos volátiles fueron encontrados), y los hechos con la técnica 4 (el cual presentó 40 compuestos volátiles). El contenido de grasa para la técnica 1 fue 29,8%, 30% para quesos de la técnica 2, 27% para quesos de la técnica 3, y 25% para los hechos con la técnica 4. Estos resultados llevan a concluir que en el más alto contenido de grasa será la más alta producción de compuestos volátiles. Los perfiles volátiles que fueron encontrados incluyen ácidos, alcoholes, hidrocarburos y ésteres. Por la prueba de Cromatografía en Capa Fina, se encontró que las proteínas de los quesos se dividían en los siguientes aminoácidos: arginina, valina, triptófano, histidina, treonina, lisina, tirosina, alanina y cisteína. En todos los tratamientos de los quesos, el sabor más destacado fue el sabor ácido, y la textura más destacada fue la textura elástica. No fueron encontradas diferencias significativas en la evaluación sensorial, para los aminoácidos libres (p>0,05), pero ácidos grasos libres y grasa mostró diferencias significativas (p<0,05).

Estudio longitudinal del impacto del tratamiento con infusores de insulina en variables psicológicas, la calidad de vida y el control glucémico de pacientes con diabetes mellitus tipo 1 / Longitudinal study of the impact of the treatment with insulin infusion in psychological, quality of life, and glycemic control of patient with type 1 diabetes mellitus

Introducción: Desde el estudio DCCT, han sido muchas las investigacionesque han intentado evaluar las distintas propuestas de terapia intensiva. Pocosestudios a largo plazo incluyen variables psicosociales. Objetivos: Evaluarvariables psicológicas y metabólicas en pacientes con diabetes tipo 1 tras 2años de tratamiento con infusión subcutánea continua de insulina (ISCI). Materialesy métodos: Veintidós pacientes con diabetes tipo 1 en tratamientocon múltiples dosis de insulina recibieron tratamiento con ISCI. Se realizó unaevaluación a los 6, 12 y 24 meses, utilizando diversos instrumentos como elBDI, el DQOL, la MHLC, el STAI y el cuestionario de miedo a las hipoglucemias.Se admitió un control glucémico adecuado con una HbA1c <7,5%. Elanálisis estadístico se realizó mediante pruebas no paramétricas y el coeficientede correlación de Pearson. Resultados: Los pacientes partían de una puntuaciónmedia en depresión de 9,55 ± 9,12 (media ± DT). En calidad devida, los datos iniciales fueron 92,95 ± 16,15, mientras que el nivel de HbA1cfue de 8,45 ± 1,59%. Al cabo de los 2 años de tratamiento, se aprecian mejorassignificativas en las puntuaciones obtenidas en depresión (p= 0,018),calidad de vida (p= 0,005) y control glucémico (p= 0,003). La ansiedad rasgoy el locus de control externo correlacionaron significativamente, encontrándoseuna fuerte relación entre el miedo a las hipoglucemias y las variablespsicológicas estudiadas. Los pacientes con mal control glucémico basal mejoraronal cabo de los 2 años de tratamiento. Conclusiones: Después de 2años con ISCI, los pacientes con diabetes tipo 1 mejoran significativamente sucalidad de vida, su control glucémico y su sintomatología depresiva(AU)

Introduction: Since the DCCT study, many studies have tried to assess differentintensive therapies. However, few long-term studies have included psychosocialvariables. Objectives: To evaluate psychological and metabolic variablesin patients with type 1 diabetes after 2 years of therapy with continuoussubcutaneous insulin infusion (CSII). Materials and methods: Twenty-twotype 1 diabetic patients treated with multiple daily injections were treated withCSII. An evaluation at 6, 12 and 24 months was performed, using several instrumentsas BDI, DQOL, MHLC and a questionnaire to evaluate fear of hypoglycaemia.Acceptable metabolic control was admitted with HbA1c <7.5%.Statistical analysis was realized using non parametric tests and Pearson’s correlationcoefficient. Results: Initially, patients had a mean score for depressionof 9.55 ± 9.12 (mean ± SD). In quality of life, initial values were 92.95 ±16.15, while the level of HbA1c was 8.45 ± 1.59%. After 2 years of treatmentwe found significant improvement in depression (p= 0.018) and quality of life(p= 0.005) scores and glycemic control (p= 0.003). Trait anxiety and externallocus of control showed a significant correlation, with a strong correlation betweenfear of hypoglycemia and the analyzed psychosocial variables. Patientswith bad basal glycemic control improved after 2 years of treatment. Conclusions:After two years with CSII, type 1 diabetic patients improve significantlytheir quality of life, glycemic control and depressive symptoms(AU)

Inadequate mycophenolic acid exposure and acute rejection in kidney transplantation.

INTRODUCTION: The clinical utility of predose levels of mycophenolic acid (MPA) monitoring among patients treated with mycophenolate mofetil (MMF) has been questioned. The aim of this study was to evaluate the impact of adequate MPA levels in the incidence of acute rejection episodes among a cohort of kidney transplant recipients. MATERIAL AND METHODS: In this retrospective study of 314 consecutive cases treated with tacrolimus, MMF, and steroids, evaluated 12-hour trough MPA samples during the first week as well as at 1, 3, 6, and 12 months as median values. RESULTS: During the first week, the median values of MPA were 1.6 microg/mL (p25-75 0.7-2.7 microg/mL) on mean doses of 1.84 +/- 0.38 g/d. The incidence of acute rejection was 28%. The mean MPA levels during the first week were significantly lower among patients who developed rejection than in nonrejectors (1.5 +/- 0.1 vs 2.1 +/- 0.1 microg/mL; P < .001). There were no significant differences in trough tacrolimus levels between rejectors and nonrejectors (11.2 +/- 0.4 vs 11.6 +/- 1.2 microg/mL; P < .78). Logistic regression analysis showed that one of the predictive factors of acute rejection was a 12-hour trough MPA <1.6 microg/mL (relative risk [RR] 2.6; CI [confidence interval] 95% 1.6-4.3; P < .001). CONCLUSIONS: Adequate MPA exposure is important to prevent acute rejection. Taking into account that the routine measurement of the area under the curve of MPA is impractical, at least the follow-up of trough MPA levels may help in the management of renal transplant recipients.

Graft outcome and mycophenolic acid trough level monitoring in kidney transplantation.

BACKGROUND: Large inter- and intrapatient variabilities have been observed in the pharmacokinetics of mycophenolic acid (MPA). As a consequence, the efficacy and safety of mycophenolate mofetil (MMF) may be optimized with individualized doses based on therapeutic drug monitoring. MATERIALS AND METHODS: In this retrospective study we analyzed; 7536 12-hour trough MPA samples obtained during the first year posttransplantation among 314 kidney recipients treated with tacrolimus, MMF, and corticosteroids. RESULTS: Despite taking similar MMF doses, patients with delayed graft function (DGF) showed lower 12-hour trough MPA levels than patients without DGF 1.4 +/- 0.1 vs 2.1 +/- 0.1 microg/mL; P = .001). There was a significant correlation between 12-hour trough MPA levels and creatinine clearance (r = .32; P < .001). Logistic regression analysis showed that creatinine clearance was a predictive factor of adequate 12-hour trough MPA levels (>1.6 microg/mL) at 7 days posttransplantation. Twelve-hour trough MPA levels at 7 days posttransplantation were lower among patients who developed an acute rejecton episode (1.5 +/- 0.1 vs 2.1 +/- 0.1 microg/mL; P < .001), whereas those with gastrointestinal side effects showed high levels (4.1 +/- 0.5 microg/mL). CONCLUSIONS: In patients with delayed or poor graft function, MMF doses greater than 2 g/d may be necessary to achieve adequate MPA levels. Therapeutic drug monitoring of MPA may be useful to prevent acute rejection episodes or toxicity.

Effects of raloxifene therapy on circulating osteoprotegerin and RANK ligand levels in post-menopausal osteoporosis.

Previous in vitro studies suggest that the anti-resorptive effect of raloxifene might be mediated by changes in several cytokines involved in the bone remodeling process. In this context, the osteoprotegerin (OPG)- receptor activator of NF kappa B ligand (RANKL) system is considered a key component in the osteoclastogenesis regulation. The aim of this study was to determine the effects of raloxifene treatment on serum concentrations of OPG, receptor RANKL and its relationship with biochemical markers of bone turnover and bone mineral density (BMD) in previously untreated women with post-menopausal osteoporosis. We selected 47 post-menopausal women (mean age 63+/-7 yr) with densitometric criteria of osteoporosis. We determined at baseline, 3, 6, and 12 months anthropometric parameters, biochemical markers of bone turnover, serum levels of 25(OH) D, serum levels of OPG and RANKL. BMD (dual-energy x-ray absorptiometry) in lumbar spine (LS) femoral neck and total hip was measured at baseline and 12 months after raloxifene (60 mg/day) treatment. Serum levels of OPG decreased in the 3rd and 6th month of treatment (p<0.001) and returned to basal levels in the 12th month. There was a significant decrease of RANKL levels and OPG/RANKL ratio after 1 yr of raloxifene treatment. In addition, BMD in LS increased significantly (2.5%) in the 12th month of treatment (p=0.031). Finally, the biochemical markers of bone turnover (total alkaline phosphatase, bone alkaline phosphatase, osteocalcin, tartrate-resistant acid phosphatase, urine cross-linked carboxi-terminal telopeptide of type I collagen) decreased significantly from the 3rd month of treatment. In conclusion, our results support the hypothesis that raloxifene may inhibit osteoclast activity, at least partly modulating the OPG-RANKL system.

Faraday waves, streaming flow, and relaxation oscillations in nearly circular containers.

Faraday waves near onset in an elliptical container are described by a third-order system of ordinary differential equations with characteristic slow-fast structure. These equations describe the interaction of standing waves with a weakly damped streaming flow driven by Reynolds stresses in boundary layers at the free surface and the rigid walls, and capture the proliferation with decreasing damping of periodic and nonperiodic relaxation oscillations observed near onset in previous simulations. These structures are the result of slow drift through symmetry-related Hopf bifurcations.

¿Cómo cuantificar la variabilidad glucémica? / How to evaluate glycemic variability?

La insulinoterapia intensiva se asocia con fluctuaciones glucémicas que pueden tener un efecto negativo en las complicaciones agudas y crónicas y en la calidad de vida de los pacientes con diabetes, por lo que su controles un objetivo terapéutico de primer nivel. La atención diabetológica de calidad supone actualmente la incorporación al seguimiento diabetológico de medidas de variabilidad glucémica como los valores promedio (hemoglobina glicosilada [HbA1c], glucemias medias, número de hipo- o hiperglucemias), las variaciones glucémicas (desviación estándar [DE] y coeficientes de variación de glucemias, valor M, MAGE [mean amplitudeof the largest glycaemic], media de las diferencias diarias [MDD] e índice de labilidad [IL]), y el riesgo de valores extremos bajos, elevados o ambos. Para cuantificar las hipoglucemias, disponemos de procedimientos para su valoración, así como del HYPO score y otros scores específicos para las «no percibidas». Todos estos índices introducen criterios objetivablesque permiten establecer categorías de pacientes en la toma de decisiones ante las nuevas y complejas propuestas terapéuticas diabetológicas (infusores de insulina, trasplantes de tejido pancreático, etc.), asícomo valorar el impacto metabólico de éstas

Intensive insulin therapy is associated with glycemic fluctuations,which may have negative effects on acute and chronic complicationsand quality of life of patients with diabetes, being the possibility ofcontrolling them a first level therapeutic objective. A good diabetescare implies the incorporation of measures of the glycemic instabilitysuch as average measures (HbA1C, glycemic average, number ofhypo or hyperglycemic events), measures of glycemic variations(standard deviation, glycemic coefficient of variation, M-value, MAGE,MODD and lability index) and measures of risk for extreme valueseither low or high values, or both. To determine the number of hypoglycaemicevents, it is simply possible to quantify them, using ahypo score or specific scores for hypoglycaemia unawareness episodes.These indexes will permit the use of objective criteria andcategorization of patients before complex therapeutic decisions suchas insulin infusion systems, pancreas transplantation, etc. were made,as well as to evaluate the metabolic impact of them

Serine dehydratase and tyrosine aminotransferase activities increased by long-term starvation and recovery by refeeding in rainbow trout (Oncorhynchus mykiss).

Here, we study a cycle of long-term starvation followed by refeeding in relation to the kinetics of serine dehydratase (SerDH) and tyrosine aminotransferase (TyrAT) in rainbow trout (Oncorhynchus mykiss). We determine SerDH- and TyrAT- specific activity at different substrate concentrations in liver and white muscle of juvenile trout starved for 70 days and then refed for 6 hr, 32 hr, 4 days, and 9 days. SerDH showed a hyperbolic kinetic with a K(m) for L-serine of 77.07+/-8.78 mM in the liver of control trout. After 70 days of starvation, the SerDH activity at saturate substrate concentration rose 100% over control. No significant changes were found in the K(m) values of the enzyme. After refeeding, the SerDH activity declined to control values. TyrAT also showed a hyperbolic kinetic with a K(m) for L-tyrosine of 1.86+/-0.12 and 2.55+/-0.57 mM in liver and white muscle, respectively. In starved trout, TyrAT activity in liver and white muscle was about 64 and 267%, respectively, higher than control. After 9 days of refeeding, the control values recovered, although, at 6 hr of refeeding, hepatic TyrAT activity was higher than that for starvation. This work shows that SerDH and TyrAT are present in rainbow trout and that the two enzymes have regulatory functions in the catabolism of their respective amino acids in this species.

AISLAMIENTO Y CARACTERIZACIÓN DE UNA POLIFENOLOXIDASA RELACIONADA CON LA TOLERANCIA DEL CLAVEL (Dianthus caryophyllus) A Fusarium oxysporum f. sp. dianthi raza 2 / Isolation and Characterization of a Polyphenoloxidase Related with Carnation (Dianthus caryophyllus) Resistence to Fusarium oxysporum f. sp. dianthi raza 2

Se purificó y caracterizó bioquímicamente la enzima polifenoloxidasa (PFO) inducida en tallos de clavel (Dianthus caryophyllus L) de variedad tolerante por inoculación con el patógeno Fusarium oxysporum f. sp. dianthi raza 2 (FOD2), causante del marchitamiento vascular. La purificación se logró a través de procesos sucesivos de cromatografía en columna de intercambio iónico, de interacción hidrofóbica y de exclusión molecular. A través de éstos se logró un factor de purificación de 314 veces con respecto al extracto inicial. La proteína purificada mostró actividad PFO y una única banda en SDSPAGE correspondiente a 40 kDa. Usando catecol como sustrato, se determinó su temperatura óptima en 45 ºC y su pH óptimo en 7,5. La enzima presentó una cinética tipo MichaelisMenten con un valor Km de 249 mM y Vmáx 322 U/min. El punto isoeléctrico (PI= 5,0) permitió establecer que se trata de una proteína de tipo ácido. Con la enzima purificada se realizaron ensayos in vitro de actividad fungitóxica, usando sus productos de reacción enfrentados al hongo FOD2, encontrándose una actividad inhibitoria importante de cerca del 57% a las 24 horas, lo que permite postular su papel en los mecanismos de defensa del clavel contra este patógeno vascular.

Polyphenoloxidase (PPO) was isolated and purified from stems of carnation (Dianthus caryophyllus L) after the inoculation with Fusarium oxysporum f. sp. dianthi race 2 (FOD2) of a tolerant variety. Purification was performed using column chromatography of ionic exchange, hydrophobic interaction and molecular exclusion. With these successive steps, a factor of 314 fold purification was achieved. The SDSPAGE analysis showed one band of 40 kDa. The purified enzyme was partially characterized using cathecol as substrate and determined the optimal temperature as 45ºC and 7.5 as optimal pH. The enzyme showed a MichaelisMenten kinetic with Km of 249 mM and Vmax 322 U/min. The IP was 5.0 indicating the acidic character of this protein. Using the purified enzyme and its reaction products, in vitro fungitoxic assays were realized indicating an important inhibitory activity against FOD2 of 57% at 24 hours. Then, it is possible to postulate that this enzyme is activated as a part of the defense mechanisms in this interaction model.