Evaluation of Success and Complications Scores for Chronic Total Occlusion Percutaneous Coronary Interventions: Insights from the Latin American Registry.

Chronic total occlusion (CTO) percutaneous coronary intervention is a complex procedure and is associated with considerable risk of complications. Several success and complication scores have been developed; however, data regarding their external validation in other populations such as Latin America are scarce. This study aimed to evaluate the accuracy of the main predictors of success and complications in a broad cohort of procedures in the Latin American (LATAM) CTO registry. From April 2008 to December 2023, 3,706 consecutive procedures listed in the LATAM CTO registry were screened. Of these, 2,835 procedures had sufficient information to analyze the Multicenter CTO Registry in Japan (J-CTO); Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS); Ostial location, Rentrop grade, and Age (ORA); Clinical and Lesion-related Score (CL-score); and EuroCTO Score (CASTLE) success scores. The complication scores were PROGRESS (MACE, mortality, and pericardiocentesis) and Outcomes, Patient health status, and Efficiency iN Chronic Total Occlusion hybrid procedures (OPEN-CTO),OPEN-CLEAN. The J-CTO and CASTLE scores demonstrated the highest areas under the curve (AUC) of 0.718 and 0.703, respectively. The AUC value for the CL-score was 0.685, whereas the PROGRESS score had an AUC of 0.598 and the ORA AUC was 0.545. The level of agreement between scores was low; only 4% of the procedures were classified as difficult or very difficult by all scores and <1% were classified as easy by all 5 scores. Of the complication scores, PROGRESS mortality (AUC 0.651) and PROGRESS MACE (AUC 0.588) showed the best performance, identifying groups with >10% event rate. These results may improve the selection of revascularization techniques, especially for patient demographics that are historically underrepresented in CTO research.

Obesity and Obesity-Related Thyroid Dysfunction: Any Potential Role for the Very Low-Calorie Ketogenic Diet (VLCKD)?

PURPOSE OF REVIEW: This review aims to explore in-depth the different aspects of the association between very low-calorie ketogenic diet (VLCKD), obesity and obesity-related thyroid dysfunction. RECENT FINDINGS: The VLCKD, proposed as a non-pharmacological strategy for the management of certain chronic diseases, is becoming increasingly popular worldwide. Initially used to treat epilepsy, it has been shown to be effective in controlling body weight gain and addressing various pathophysiological conditions. Research has shown that a low-calorie, high-fat diet can affect thyroid hormone levels. Weight loss can also influence thyroid hormone levels. Studies have suggested that long-term use of VLCKD for refractory epilepsy may be related to the development of hypothyroidism, with an effect seen in various populations. In particular, women with obesity following VLCKD tend to have reduced T3 levels. We propose further research to unravel the underlying mechanisms linking VLCKD to obesity and obesity-related thyroid dysfunction.

Effects of Larrea nitida nanodispersions on the growth inhibition of phytopathogens.

Larrea nitida Cav. (Zygophyllaceae) is a plant endemic to Argentina and Chile, and its extract has been studied over the last years due to the presence of antimicrobial agents that can be used to control the growth of some pathogens in agriculture. However, the extract is highly hydrophobic, which strongly affects its fungicidal activity in aqueous media. In this sense, the solid dispersion technique was used to produce L. nitida extract nanodispersions with polyethylene glycol (PLE) and with polyethylene glycol and zinc acetate (PZLE). In order to further evaluate the activity of the extract in PLE and PZLE, blank nanodispersions containing only polyethylene glycol (PEG) and zinc acetate (PZ) without the addition of the extract were also produced. The fungicidal activity of the water-soluble nanoparticles was evaluated at different concentrations (0.037-0.110 g.mL-1). In general, the nanoparticles were successfully produced on a nanometric size and presented a significant inhibitory activity on the growth of the pathogens Fusarium oxysporum and Fusarium verticillioides in aqueous media. Compared to PLE, PZLE presented increased fungistatic activity, possibly due to their increased solubility in water. Even though their application in agriculture should be further investigated, the nanodispersions present great potential to be applied as a green biotechnological tool.

Nutrition intake in critically ill patients with coronavirus disease (COVID-19): A nationwide, multicentre, observational study in Argentina.

INTRODUCTION: In 2020 the pandemic caused by SARS-COV-2 demanded an enormous number of healthcare resources in order to guarantee adequate treatment and support for those patients. This study aims to assess caloric and protein intake and evaluate its associations with relevant clinical outcomes in critically ill with coronavirus disease (COVID-19) patients. METHODS: A nationwide, multicentre prospective observational study including twelve Argentinian intensive care units (ICUs,) was conducted between March and October 2020. INCLUSION CRITERIA: Adult ICU patients>18 years admitted to the ICU with COVID-19 diagnosis and mechanical ventilation for at least 48h. Statistical analysis was carried out using IBM-SPSS© 24 programme. RESULTS: One hundred and eighty-five patients were included in the study. Those who died had lower protein intake (0.73g/kg/day (95% confidence interval (CI) 0.70-0.75 vs 0.97g/kg/day (CI 0.95-0.99), P<0.001), and lower caloric intake than those who survived (12.94kcal/kg/day (CI 12.48-13.39) vs 16.47kcal/kg/day (CI 16.09-16.8), P<0.001). A model was built, and logistic regression showed that factors associated with the probability of achieving caloric and protein intake, were the early start of nutritional support, modified NUTRIC score higher than five points, and undernutrition (Subjective Global Assessment B or C). The patients that underwent mechanical ventilation in a prone position present less caloric and protein intake, similar to those with APACHE II>18. CONCLUSIONS: Critically ill patients with COVID-19 associated respiratory failure requiring mechanical ventilation who died in ICU had less caloric and protein intake than those who survived. Early start on nutritional support and undernutrition increased the opportunity to achieve protein and caloric goals, whereas the severity of disease and mechanical ventilation in the prone position decreased the chance to reach caloric and protein targets.

Nutrition intake in critically ill patients with coronavirus disease (COVID-19): A nationwide, multicentre, observational study in Argentina.

Introduction: In 2020 the pandemic caused by SARS-COV-2 demanded an enormous number of healthcare resources in order to guarantee adequate treatment and support for those patients. This study aims to assess caloric and protein intake and evaluate its associations with relevant clinical outcomes in critically ill with coronavirus disease (COVID-19) patients. Methods: A nationwide, multicentre prospective observational study including twelve Argentinian intensive care units (ICUs,) was conducted between March and October 2020. Inclusion criteria: Adult ICU patients > 18 years admitted to the ICU with COVID-19 diagnosis and mechanical ventilation for at least 48 h. Statistical analysis was carried out using IBM-SPSS© 24 programme. Results: One hundred and eighty-five patients were included in the study. Those who died had lower protein intake (0.73 g/kg/day (95% confidence interval (CI) 0.70-0.75 vs 0.97 g/kg/day (CI 0.95-0.99), P < 0.001), and lower caloric intake than those who survived (12.94 kcal/kg/day (CI 12.48-13.39) vs 16.47 kcal/kg/day (CI 16.09-16.8), P < 0.001).A model was built, and logistic regression showed that factors associated with the probability of achieving caloric and protein intake, were the early start of nutritional support, modified NUTRIC score higher than five points, and undernutrition (Subjective Global Assessment B or C). The patients that underwent mechanical ventilation in a prone position present less caloric and protein intake, similar to those with APACHE II > 18. Conclusions: Critically ill patients with COVID-19 associated respiratory failure requiring mechanical ventilation who died in ICU had less caloric and protein intake than those who survived. Early start on nutritional support and undernutrition increased the opportunity to achieve protein and caloric goals, whereas the severity of disease and mechanical ventilation in the prone position decreased the chance to reach caloric and protein targets.

Introducción: En 2020, la pandemia provocada por el SARS-COV-2 demandó una enorme cantidad de recursos sanitarios para garantizar el tratamiento y apoyo adecuado a estos pacientes. Este estudio tiene como objetivo evaluar la ingesta de calorías/proteínas y evaluar sus asociaciones con resultados clínicos relevantes en pacientes críticamente enfermos con enfermedad por coronavirus (COVID-19). Métodos: Se realizó un estudio observacional prospectivo multicéntrico a nivel nacional que incluyó 12 unidades de cuidados intensivos (UCI) argentinas entre marzo y octubre de 2020. Criterios de inclusión: pacientes adultos de la UCI > 18 años ingresados en la UCI con diagnóstico de COVID-19 y ventilación mecánica durante al menos 48 h. El análisis estadístico se realizó mediante el programa IBM-SPSS© 24. Resultados: En el presente estudio se incluyeron 185 pacientes. Entre los que fallecieron se observó un aporte proteico más bajo (0,73 g/kg/día [intervalo de confianza {IC} del 95% 0,70-0,75] vs. 0,97 g/kg/día [IC 0,95-0,99], p < 0,001), y menor aporte calórico que los que sobrevivieron (12,94 kcal/kg/día [IC 12,48-13,39] vs. 16,47 kcal/kg/día [IC 16,09-16,8], p < 0,001).Se construyó un modelo de regresión logística para analizar qué factores estaban asociados con la probabilidad de lograr los objetivos calóricos/proteicos. Se observó una mayor probabilidad de lograr dichos objetivos cuando el inicio del soporte nutricional era precoz, el puntaje NUTRIC modificado era superior a 5 puntos y el paciente tenía diagnóstico de desnutrición mediante la Evaluación Global Subjetiva(B o C). Por otra parte, en los pacientes que necesitaron ventilación mecánica en decúbito prono se observó menor aporte calórico y proteico, situación similar en aquellos con APACHE II > 18. Conclusiones: Los pacientes críticos con insuficiencia respiratoria asociada a la enfermedad por COVID-19 que requerían ventilación mecánica y que fallecieron en la UCI tuvieron una ingesta calórica y proteica menor que los que sobrevivieron. El inicio temprano del soporte nutricional y la desnutrición aumentaron la posibilidad de alcanzar los objetivos calóricos y proteicos, mientras que la gravedad de la enfermedad y la ventilación mecánica en decúbito prono disminuyeron la posibilidad de alcanzar los objetivos calóricos y proteicos.

Impacto da técnica de dissecção/ reentrada anterógrada nas intervenções coronárias percutâneas para oclusão crônica: registro LATAM Chronic Total Occlusion / Impact of antegrade dissection and re-entry technique on coronary percutaneous interventions for chronic total occlusion: the LATAM Chronic Total Occlusion registry

Introdução: As mais novas técnicas de intervenção coronária percutânea em oclusões crônicas podem melhorar o sucesso técnico. Os objetivos deste estudo foram descrever a segurança e a eficácia da técnica de dissecção/reentrada anterógrada como estratégia inicial de revascularização. Métodos: Registro multicêntrico de países latino-americanos (LATAM Chronic Total Occlusion). Analisamos as características iniciais e os desfechos dos casos em que foi empregada dissecção/ reentrada anterógrada como estratégia primária ou de resgate após escalonamento de fios por via anterógrada. Foram excluídos os casos de abordagem retrógrada. Os médicos usaram dissecção anterógrada convencional e técnica de reentrada. Resultados: Dos 1.875 pacientes analisados, em 50 foi planejada a dissecção/reentrada anterógrada, e, em 1.825, foi planejado o escalonamento de fios por via anterógrada primário. Deu-se preferência à dissecção/reentrada anterógrada em pacientes mais idosos e com história de revascularização (revascularização do miocárdio: dissecção/ reentrada anterógrada em 33,3% e escalonamento de fios por via anterógrada primário em 13,4%, com p<0,001; intervenções coronárias percutâneas em 66,6 e 48,8%, respectivamente, com p=0,012). Oclusões crônicas mais longas (30mm [22-41] e 21mm [15-30], p<0,001) e calcificações moderadas ou graves (62 e 42,6%, com p=0,008) foram associadas à seleção da dissecção/reentrada anterógrada primária, ao invés do escalonamento de fios por via anterógrada primário. Houve correlação significativa entre o aumento do escore J-CTO (X2=37, df=5; p<0,001) e o uso da dissecção/ reentrada anterógrada. O escalonamento de fios por via anterógrada primário teve taxa de sucesso de 88,4%, e a dissecção/reentrada anterógrada, de 76,7%. Para o escalonamento de fios por via anterógrada primário e dissecção/reentrada anterógrada de resgate, o uso do dispositivo CrossBoss® foi relacionado às maiores taxas de sucesso (92,3 e 82,7%, respectivamente). Os desfechos a curto prazo foram semelhantes nos grupos. Conclusão: Na América Latina, a técnica de dissecção/ reentrada anterógrada foi segura e efetiva, tanto como estratégia primária quanto de resgate, mesmo quando utilizada em lesões de maior complexidade. O uso de dispositivos específicos foi relacionado a uma maior taxa de sucesso.

Background: The newest techniques of percutaneous coronary interventions for chronic total occlusion may improve technical success. The objectives were to describe safety and efficacy of antegrade dissection and reentry technique as initial revascularization strategy. Methods: A multicenter registry from Latin American countries (LATAM Chronic Total Occlusion). Baseline characteristics and outcomes of cases using antegrade dissection and reentry as primary strategy or bailout of antegrade wire escalation were analyzed. Retrograde approach cases were excluded. Physicians used conventional antegrade dissection and reentry technique. Results: Out of 1,875 patients analyzed, 50 were planned primary antegrade dissection and reentry and 1,825 planned primary antegrade wire escalation. Primary antegrade dissection and reentry was preferred in older patients, with a history of revascularization (coronary artery bypass graft: primary antegrade dissection and reentry in 33.3% and primary antegrade wire escalation in 13.4%; p<0.001; percutaneous coronary interventions in 66.6% and 48.8%, respectively; p=0.012). Longer chronic total occlusions (30mm [22-41] and 21mm [15-30]; p<0.001), moderate or severe calcification (62% and 42.6%; p=0.008) were associated with the selection of primary antegrade dissection and reentry, instead of primary antegrade wire escalation. There was a significant correlation between increasing J-CTO score (X2=37, df=5; p<0.001), and use of primary antegrade dissection and reentry. Primary antegrade wire escalation had a success rate of 88.4%, and primary antegrade dissection and reentry of 76.7%. For primary antegrade wire escalation and bailout antegrade dissection and reentry, the use of the CrossBoss® device was related to the highest rates of success (92.3 and 82.7%, respectively). Short-term outcomes were similar in both groups. Conclusion: In Latin America, antegrade dissection and reentry was safe and effective, both as primary or bailout strategy, even when used for higher complexity lesions. The use of dedicated devices was related to a higher success rate.

Gut microbiota and obesity: New insights.

Obesity is a pathology whose incidence is increasing throughout the world. There are many pathologies associated with obesity. In recent years, the influence of the microbiota on both health and pathological states has been known. There is growing information related to changes in the microbiome and obesity, as well as its associated pathologies. Changes associated with age, exercise, and weight changes have been described. In addition, metabolic changes associated with the microbiota, bariatric surgery, and fecal matter transplantation are described. In this review, we summarize the biology and physiology of microbiota in obese patients, its role in the pathophysiology of several disorders associated, and the emerging therapeutic applications of prebiotics, probiotics, and fecal microbiota transplantation.

Nasoenteric tube doppler guided insertion. A case report and review of literature.

Nasoenteric tube placement is needed in patients with gastric enteral feeding intolerance or high risk of aspiration. Several techniques are described. Ultrasound is used more commonly for gastric tube placement, but also is described in enteral tube feeding placement. Doppler technique with cold water injection is not described in the literature. We describe a new and easy to realize technique. A case of a 65 years old male patient in the intensive care unit (ICU) with gastroparesis is described. Before beginning a prokinetic drug was administered. In this technique gastric tube placement was bedside assessed with ultrasound, and then the tube was progressed with cold water injection. Duodenal position was confirmed with doppler ultrasound. Ultrasound and doppler technique for nasoenteric tube placement could be a feasible technique to use in the ICU. More studies are needed to assess the effectiveness of the technique.

Nutritional risk and clinical outcomes in critically ill adult patients with COVID-19.

INTRODUCTION: Introduction: the COVID-19 pandemic put the world's population at risk. As the relationship between nutritional risk and clinical outcomes in critically ill patients with COVID-19 is still poorly understood, a multidisciplinary research team of the Argentine Society of Intensive Care (SATI) conducted a multicenter study aimed to define nutritional features, and to evaluate the relationship between nutritional risk and relevant clinical outcomes for COVID-19 patients in an intensive care unit (ICU). Methods: a multicenter, prospective, observational study including twelve Argentinian ICUs was conducted between March and October 2020. Inclusion criteria were: adult patients older than 18 years who were admitted to the ICU with a COVID-19 diagnosis were included. Clinical data included comorbidities scores, and nutritional screening tools such as the Subjective Global Assessment (SGA), the Nutritional Risk Screening (NRS) 2002, and the modified NUTRIC score (mNUTRIC SCORE) were used. In addition, clinical outcomes including overall mortality, mechanical ventilation (MV) days, and ICU and hospital length of stay (LOS) were recorded. Results: a total of 285 ICU patients met our inclusion criteria. Mean age was 61.24 (SD = 14.6) years; APACHE-II, 14.2 (SD = 6.6); Charlson Comorbidity Index (CCI), 2.3 (SD = 2.3). Most patients were admitted from the emergency room to the ICU. Hypertension, obesity, and diabetes were the most common comorbidities. Nutritional assessment showed that 36.9 % were SGA B+C, and 46 % were obese. Mean ICU LOS was 22.2 (SD = 19.5), and hospital LOS was 28.1 (SD = 21.9) days. Of all patients, 90.2 % underwent MV, and MV days were 20.6 (SD = 15.6). The univariate and multivariate analyses showed that risk factors for COVID-19 mortality were (odds ratio [95 % confidence interval]): SGA score of B or C: 2.13 [1.11-4.06], and NRS 2002 ≥ 3: 2.25 [1.01-5.01]. Conclusions: in the present study, nutritional status (SGA) and NRS 2002 were major mortality risk factors for CODIV-19 patients in the ICU.

INTRODUCCIÓN: Introducción: la pandemia de COVID-19 puso en riesgo a la población mundial. Dado que la relación entre el riesgo nutricional y los resultados clínicos en pacientes críticos con COVID-19 es aún poco conocida, un equipo de investigación multidisciplinario de la Sociedad Argentina de Cuidados Intensivos (SATI) realizó un estudio multicéntrico con el objetivo de definir las características nutricionales y evaluar la relación entre el riesgo nutricional y los resultados clínicos relevantes para los pacientes de la unidad de cuidados intensivos (UCI) de COVID-19. Métodos: entre marzo y octubre de 2020 se realizó un estudio observacional prospectivo y multicéntrico que incluyó 12 UCI argentinas. Criterios de inclusión: se incluyeron pacientes adultos mayores de 18 años que habían ingresado en la UCI con diagnóstico de COVID-19. Se utilizaron datos clínicos que incluían scores de comorbilidades, herramientas de cribado nutricional como la Evaluación Global Subjetiva (EGS) y el Cribado de Riesgo Nutricional (NRS) 2002, y la puntuación NUTRIC. Además. Se registraron los resultados clínicos, incluida la mortalidad, los días de ventilación mecánica (VM) y la duración de la estancia en la UCI y hospitalaria en general. Resultados: en total, 285 pacientes en UCI cumplieron nuestros criterios de inclusión. La edad media fue de 61,24 (DE = 14,6) años, la puntuación APACHE-II de 14,2 (DE = 6,6) y el índice de comorbilidad de Charlson (ICC) de 2,3 (DE = 2,3). La mayoría de los pacientes ingresaron desde la sala de emergencias a la UCI. La hipertensión, la obesidad y la diabetes fueron las comorbilidades más frecuentes. La evaluación nutricional mostró que el 36,9 % eran VGS B + C y el 46 % eran obesos. La estancia en la UCI fue de 22,2 (DE = 19,5) y la hospitalaria de 28,1 (DE = 21,9) días. El 90,2 % se sometieron a VM, siendo la media de días de VM de 20,6 (DE = 15,6). El análisis univariado y multivariado mostró que los factores de riesgo de mortalidad por COVID-19 eran (razón de posibilidades [intervalo de confianza del 95 %]): puntuación SGA de B o C: 2,13 [1,11-4,06], y NRS 2002 ≥ 3: 2,25 [1,01-5,01]. Conclusiones: en el presente estudio, el estado nutricional (EGS) y el NRS 2002 fueron los principales factores de riesgo de mortalidad para los pacientes con COVID-19 en la UCI.

Pancreatitis Induced by Cocaine.

Pancreatitis is one of the commonest diseases of the gastrointestinal tract, characterized by epigastric pain of moderate to severe intensity, which radiates to the back, elevation of pancreatic lipase and amylase enzymes, and changes in pancreatic parenchyma in imaging methods. The most common etiologies vary, generally the most frequent being biliary lithiasis and alcohol, followed by hypertriglyceridemia. Among the less frequent causes is drug-induced pancreatitis. We report a case of acute pancreatitis caused by cocaine, rarely described in literature.

Analysis of the P1 promoter in response to UV-B radiation in allelic variants of high-altitude maize.

BACKGROUND: Plants living at high altitudes are typically exposed to elevated UV-B radiation, and harbor mechanisms to prevent the induced damage, such as the accumulation of UV-absorbing compounds. The maize R2R3-MYB transcription factor P1 controls the accumulation of several UV-B absorbing phenolics by activating a subset of flavonoid biosynthetic genes in leaves of maize landraces adapted to high altitudes. RESULTS: Here, we studied the UV-B regulation of P1 in maize leaves of high altitude landraces, and we investigated how UV-B regulates P1 binding to the CHS promoter in both low and high altitude lines. In addition, we analyzed whether the expansion in the P1 expression domain between these maize landraces and inbred lines is associated to changes in the molecular structure of the proximal promoter, distal enhancer and first intron of P1. Finally, using transient expression experiments in protoplasts from various maize genotypes, we investigated whether the different expression patterns of P1 in the high altitude landraces could be attributed to trans- or cis-acting elements. CONCLUSIONS: Together, our results demonstrate that, although differences in cis-acting elements exist between the different lines under study, the different patterns of P1 expression are largely a consequence of effects in trans.

L-Teanina, ¿un aminoácido proveniente del té verde, con múltiples efectos sobre el SNC? / L-Theanine: an amino acid of green tea with multiple effects on the CNS?

El té es la segunda bebida de mayor consumo a nivel mundial después del agua. Esta bebida posee un efecto relajante y placentero. Ambas cualidades provienen de un aminoácido que se encuentra en grandes concentraciones en las hojas del té verde, la L-Teanina. Este aminoácido tiene la capacidad de atravesar la barrera hemato-encefálica y modular las funciones cerebrales, a través de su acción sobre los neurotransmisores y por su capacidad de alterar las ondas cerebrales a un predominio alfa, que es el patrón relacionado con la relajación y concentración. Este aminoácido tiene efecto anti-estrés, aumenta la memoria y concentración, mejora la calidad del sueño y actúa como un neuroprotector. A estos efectos sobre el SNC se puede sumar sus posibles usos junto con doxorubicina y otros antineoplásicos, mejorando sus acciones y disminuyendo su toxicidad.(AU)

L-Theanine, an amino acid of green tea, has the ability to modulate brain functions by causing an anti-stress effect, by improving memory and concentration and enhancing sleep, as well as by acting as a neuroprotective agent.(AU)

L-Teanina, ¿un aminoácido proveniente del té verde, con múltiples efectos sobre el SNC? / L-Theanine: an amino acid of green tea with multiple effects on the CNS?

El té es la segunda bebida de mayor consumo a nivel mundial después del agua. Esta bebida posee un efecto relajante y placentero. Ambas cualidades provienen de un aminoácido que se encuentra en grandes concentraciones en las hojas del té verde, la L-Teanina. Este aminoácido tiene la capacidad de atravesar la barrera hemato-encefálica y modular las funciones cerebrales, a través de su acción sobre los neurotransmisores y por su capacidad de alterar las ondas cerebrales a un predominio alfa, que es el patrón relacionado con la relajación y concentración. Este aminoácido tiene efecto anti-estrés, aumenta la memoria y concentración, mejora la calidad del sueño y actúa como un neuroprotector. A estos efectos sobre el SNC se puede sumar sus posibles usos junto con doxorubicina y otros antineoplásicos, mejorando sus acciones y disminuyendo su toxicidad.(AU)

L-Theanine, an amino acid of green tea, has the ability to modulate brain functions by causing an anti-stress effect, by improving memory and concentration and enhancing sleep, as well as by acting as a neuroprotective agent.(AU)

L-Teanina, ¿un aminoácido proveniente del té verde, con múltiples efectos sobre el SNC? / L-Theanine: an amino acid of green tea with multiple effects on the CNS?

El té es la segunda bebida de mayor consumo a nivel mundial después del agua. Esta bebida posee un efecto relajante y placentero. Ambas cualidades provienen de un aminoácido que se encuentra en grandes concentraciones en las hojas del té verde, la L-Teanina. Este aminoácido tiene la capacidad de atravesar la barrera hemato-encefálica y modular las funciones cerebrales, a través de su acción sobre los neurotransmisores y por su capacidad de alterar las ondas cerebrales a un predominio alfa, que es el patrón relacionado con la relajación y concentración. Este aminoácido tiene efecto anti-estrés, aumenta la memoria y concentración, mejora la calidad del sueño y actúa como un neuroprotector. A estos efectos sobre el SNC se puede sumar sus posibles usos junto con doxorubicina y otros antineoplásicos, mejorando sus acciones y disminuyendo su toxicidad.

L-Theanine, an amino acid of green tea, has the ability to modulate brain functions by causing an anti-stress effect, by improving memory and concentration and enhancing sleep, as well as by acting as a neuroprotective agent.

Two phosphoenolpyruvate carboxykinases coexist in the Crassulacean Acid Metabolism plant Ananas comosus. Isolation and characterization of the smaller 65 kDa form.

Two phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.49) isoforms of 74 and 65 kDa were found to coexist in vivo in pineapple leaves, a constitutive Crassulacean Acid Metabolism plant. The 65 kDa form was not the result of proteolytic cleavage of the larger form since extraction methods reported to prevent PEPCK proteolysis in other plant tissues failed to yield a single immunoreactive PEPCK polypeptide in leaf extracts. In this work, the smaller form of 65 kDa was purified to homogeneity and physically and kinetically characterized and showed parameters compatible with a fully active enzyme. The specific activity was nearly twice higher for decarboxylation of oxaloacetate when compared to carboxylation of phosphoenolpyruvate. Kinetic parameters fell within the range of those estimated for other plant PEPCKs. Its activity was affected by several metabolites, as shown by inhibition by 3-phosphoglycerate, citrate, malate, fructose-1,6-bisphosphate, l-asparagine and activation of the decarboxylating activity by succinate. A break in the Arrhenius plot at about 30°C indicates that PEPCK structure is responsive to changes in temperature. The results indicate that pineapple leaves contain two PEPCK forms. The biochemical characterization of the smaller isoform performed in this work suggests that it could participate in both carbon and nitrogen metabolism in vivo by acting as a decarboxylase.