Analysis of apheresis outcomes in a cohort of Chilean patients treated with autologous stem cell transplantation: A single center real-world experience.

Adequate stem cell harvesting is required for autologous hematopoietic transplantation. In deficient mobilizer patients, the collection of stem cells can be challenging because of the impossibility of achieving satisfactory CD34 cell counts with GCSF + - chemotherapy. Plerixafor is a potent and expensive drug that promotes the release of stem cells from the medullary niche to the peripheral blood and allows satisfactory harvests. We performed a retrospective analysis of 370 patients with myeloma and lymphoma harvested at our institution. 99 % of patients achieved satisfactory apheresis using Plerixafor in 45 %. Satisfactory harvests were obtained in patients mobilized with GCSF or plerixafor. In patients who used plerixafor, it was necessary to perform fewer apheresis procedures (P = 0.05). In multivariate analysis, the only factor that predicted the need for plerixafor was the presence of less than 30,000 CD34 / ul on the day of apheresis (OR 0.3. p < 0.001). Since we adopted the plerixafor protocol guided by CD34 counts, the number of patients with harvest failure has decreased. In conclusion, the rational and standardized use of plerixafor favors satisfactory harvest in patients who require autologous transplantation in South-American patients.

Emotional and Cognitive Preservice Science Teachers' Engagement While Living a Model-Based Inquiry Science Technology Engineering Mathematics Sequence About Acid-Base.

Science inquiry and modeling activities have been proved to heighten emotional situations; therefore, research about emotions should aim to identify which activities promote student engagement with Science, Technology, Engineering and Mathematics fields through multidimensional models that include emotional and cognitive engagement. This research is focused on science teachers' need to carefully review their classroom instructions to ensure that students are provided with opportunities to develop appropriate understandings of acid/base models (and their concepts). To achieve this, we have implemented a short model-based inquiry acid-base instructional sequence in the context of a TV-spot about chewing gum. A descriptive, non-experimental quantitative methodology with a heuristic (emotional: self-report questionnaire; and cognitive: self-regulation questionnaire) has been used to analyze what Pre-Service Secondary Education Teachers from several Spanish universities recognize to have learned and felt in each activity. Differences regarding knowledge declared by the participants were identified in all the tasks from before to after carrying them out. Furthermore, the results seem to indicate that there are significant relationships between the knowledge and the emotions, being different depending on the skill involved. Significant correlations between emotions have been found. However, there were no significant correlations with either rejection and knowledge or with other emotions, which points to emotional engagement. Generally, no significant differences were identified between emotions and gender or universities, with some exceptions between genders in two tasks. Thus, the results led us to reflect on the instructional sequence implementation's ability to bring awareness to the learning process and how it produces multidimensional engagements.

COVID-19 Cliff Notes: A COVID-19 Multidisciplinary Care Compendium.

As we pass the nearly 9 month mark of the coronavirus virus disease 2019 (COVID-19) pandemic in the United States, we sought to compile a brief multi-disciplinary compendium of COVID-19 information learned to date. COVID-19 is an active viral pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that confers high morbidity and mortality. COVID-19 has been associated with: pulmonary compromise and acute respiratory distress syndrome, thrombotic events, inflammation and cytokine, and post-infectious syndromes. Mitigation of these complications and expeditious therapy are a global urgency; this is brief summary of current data and management approaches synthesized from publications, experience, cross-disciplinary expertise (Figure 1).

Tendencia de la mortalidad no relacionada con Covid-19 en la región del Bio-Bio, periodo 2016-2020 / Mortality trand not related to Covid-19 in the Bio-Bio, period 2016-2020

INTRODUCCIÓN: La pandemia por SARS-COV-2 ha generado mortalidad por exceso, aun así, se deben revisar la mortalidad atribuida a otras enfermedades. El siguiente trabajo pretende identificar la tendencia de mortalidad no relacionada con COVID-19 en la región del Bio-bio, periodo 2016-2020. Material y Método: Estudio descriptivo, ecológico, longitudinal. Se estudió la población de la región del Biobío, periodo 2016-2020. Los datos se obtuvieron del departamento de estadística e información en Salud. Se estudió: Distribución etaria, sexo, tasa de mortalidad general y específica, y promedio anual del número de muertos en el periodo 2016-2019; excluyendo la causa de muerte por enfermedad COVID-19 o sospechosa de COVID-19. Se realizó un análisis descriptivo. Se utilizó el programa Microsoft Excel 365® para análisis. Resultados: 2016-2019 fallecieron más hombres (n=19.110; 53,00%), siendo el principal grupo etario de 75-79 años (n=2.433; 12,73%), en el caso de las mujeres fue el grupo de 90-99 años (n=2.832; 16,71%). En 2020, fallecieron más hombres que mujeres, de los mismos grupos etarios respectivamente. Tasa de mortalidad general 2020 fue 544,39 x100.000 hbts., inferior a la de otros años, excepto en 2016. Sin embargo, el periodo Enero-abril 2020, la tasa de mortalidad es mayor comparado con los años anteriores. El promedio de muertes 2016-2019 fue 9.016,0 ±186,5, siendo el total en 2020 n=9.057. Discusión: La pandemia ha afectado a pacientes con patologías que han presentado una atención poco efectiva u inoportuna, falleciendo por el SARS-COV-2 o por sus comorbilidades, camuflándose sus registros. Lo cual dificultará interpretar dichos valores.

INTRODUCTION: The SARS-COV-2 pandemic has generated excess mortality, even so, the mortality attributed to other diseases should be reviewed. The study objective was to identify the mortality trend unrelated to COVID-19 in the Bio-bio Region between 2016-2020. Material and Method: Descriptive, ecological, longitudinal study. The population of the Biobío region was studied between the years 2016-2020. Data were obtained from the Department of Statistics and Health Information, DEIS. It was studied: Age distribution, sex, general and specific mortality rate, annual average of the number of deaths between 2016-2020, excluding mortality from (or suspected) COVID-19 disease. A descriptive analysis was performed. Microsoft Excel 365® software was used for the analysis. Results: 2016-2019 mortality rate was higher for men (n=19,110; 53.00%), with the highest rates in the 75-79 years group (n=2,433; 12.73%); women 90- 99 years (n=2,832; 16.71%) presented the highest mortality rates. In 2020 more men than women continued to die in the same age groups, respectively. The general mortality rate 2020 was 544,39 x 100,000 inhabitants, which is lower than that of any other year, except for 2016. However, from January to April 2020, the mortality rate was higher when compared to the previous years. The average of deaths 2016-2019 was 9,016.0 ± 186.5, meanwhile in the same period in 2020 was 9,057. Discussion: The pandemic has affected patients with pathologies who have presented ineffective or untimely care, dying from SARS-COV-2 or its comorbidities, then their records get camouflaged, which will make it difficult to interpret these values.

[Phenotype proposal for early diagnosis of possibility of metabolic syndrome in school children aged 6 to 15 years]. / Propuesta de fenotipo para diagnóstico temprano de posibilidad de síndrome metabólico en escolares de seis a 15 años.

INTRODUCTION AND OBJECTIVES: Obesity and metabolic syndrome (MS) continue to be a problem at a socioeconomic level, causing high morbidity and mortality in the adult population. Prevention of risk factors should be carried out from an early age. Currently, there is no consensus on the opportune moment to start an intervention or treatment, regarding metabolic syndrome. The objective of the study is to describe the phenotype to predict early diagnosis of metabolic syndrome in schoolchildren. MATERIAL AND METHODS: Observational, prospective, cross-sectional and analytical study in schoolchildren from 6 to 15 years old, conducted in Guayaquil. Anthropometric measurements and a survey were performed, obtaining signing informed consent. The IBM Watson artificial intelligence (AI) platform with its software Modeler Flow, were used for the analysis. RESULTS: A population of 1025 students between 6 and 15 years old (mean of 12 years for men and 13 years for women) was examined, of whom 62.3% were men and 37.7% women. 23.9% of the population was overweight and 14% obese. A greater tendency to weight alteration was observed in men than in women (51.37% vs 47.79%), and a lower waist circumference in men (85 cm vs 87 cm, respectively). Males had a higher level of systolic blood pressure (SBP), being within the 90th percentile (mean SBP of 123 mmHg) 61.2%, compared to 38.8% of women, with a p < 0.001. Sedentary lifestyle is similar in both groups, with an average of 4.79 hours in front of the screen and/or video games. A statistically significant correlation was demonstrated between SBP and the waist/height ratio (WHtR) in the 90th percentile and 95th percentile (X2 9.075, p < 0.028, and X2 23,54, p < 0,000 respectively), as well as a relationship between 95th percentile and sex (X2 11.57, p < 0.001). The Modeler Flow software showed us that if WHtR, > 0.46, weight > 56.1 kg and height > 1.61 m, the probability of presenting metabolic syndrome, was of 82.4%. The statistic of this study has a predictive accuracy of 90% (error deviation of 0.009). The importance in the predictors of metabolic syndrome, range from 97.57% to 100%. CONCLUSIONS: A prevalence of 33.9% of metabolic syndrome was observed in schoolchildren from 6 to 15 years old, with pathological cut-off points of: WHtR > 0.46, weight > 56.1 kg, pure sedentary lifestyle > 3 hours in front of the screen/playing video games, and SBP within the 90th percentile (> 123 mmHg). With these four indicators, we can predict a probability of early diagnosis of metabolic syndrome of 97% to 100%.

Política, Empoderamiento y Género en Venezuela / Policies, empowerment and gender in Venezuela

Ineludiblemente se reconoce que la mujer venezolana ha logrado ocupar un espacio significativo en la esfera pública nacional, sin embargo persiste la enorme brecha de mujeres que aún se mantienen invisibles ante los problemas que les aquejan. Avanzar políticamente desde el enfoque de género, implica remontarse a la construcción colectiva de ser mujer y ser hombre no solo en la sociedad venezolana sino en Latinoamericana. El objetivo del presente ensayo es, generar elementos de discusión que permitan abordar el tema de la política, empoderamiento y género en la mujer venezolana. La metodología empleada para cumplir con el objetivo consistió en una revisión documental en función de interpretar y comprender el fenómeno de estudio. Estudiar el género desde su categoría, especifica y tipificada en cuanto al empoderamiento conduce a analizar uno de sus ejes transversales como lo es el de las políticas públicas. Se considera que aún falta mucho camino por transitar en Venezuela, no se puede negar los avances en materia de género que se han tenido, sin embargo sigue siendo necesario unir esfuerzos para reducir la pobreza y las inequidades. Transcender del poder hegemónico del patriarcado, redefinir los roles de poder del hombre y la mujer implica una ardua y larga tarea llenas de acciones, estrategias, lineamientos e instauración de nuevas formas de pensar. Crear políticas públicas en materia de género y que la mujer logre empoderarse, involucra un conjunto de elementos a las cuales ella está expuesta, atendiendo a la creación de condiciones para satisfacer sus necesidades.

Inevitably recognizes the Venezuelan women than UN has managed to occupy significant space in the national public sphere, sin embargo remains a huge gap of women still remain invisible to the problems facing them. Politically advance from the gender perspective, implications traced back to the collective construction of being a woman or man not only in Venezuelan society Sino-Latin American. The aim of this essay is generated discussion items that will address the issue of the Policy, Gender empowerment and Venezuelan women. The methodology paragraph fulfill the objective consisted of a literature review in function to interpret and understand the phenomenon of study. Study the genre from its category, specific and typified in The empowerment Analyze lead one of its transverse axes such as the Public Policy. It is considered that still much remains to move in Venezuela, there is no denying the progress in gender that have been taken, sin embargo is still necessary to join efforts for reduce poverty and inequities. Transcend the hegemonic power of patriarchy, Power redefine the roles of men and women implications A long and arduous task Full Of Action, strategies, guidelines and establishment of new ways of thinking. Create public policies on gender and which empower women Achieve, involves UN Set of elements which she is exposed, based on the creation of conditions for suit your needs.

Activation of the PI3K/AKT pathway by microRNA-22 results in CLL B-cell proliferation.

Chronic lymphocytic leukemia (CLL) is characterized by accumulation of clonal B cells arrested in G0/G1 stages that coexist, in different proportions, with proliferative B cells. Understanding the crosstalk between the proliferative subsets and their milieu could provide clues on CLL biology. We previously identified one of these subpopulations in the peripheral blood from unmutated patients that appears to be a hallmark of a progressive disease. Aiming to characterize the molecular mechanism underlying this proliferative behavior, we performed gene expression analysis comparing the global mRNA and microRNA expression of this leukemic subpopulation, and compared it with their quiescent counterparts. Our results suggest that proliferation of this fraction depend on microRNA-22 overexpression that induces phosphatase and tensin homolog downregulation and phosphoinositide 3-kinase (PI3K)/AKT pathway activation. Transfection experiments demonstrated that miR-22 overexpression in CLL B cells switches on PI3K/AKT, leading to downregulation of p27(-Kip1) and overexpression of Survivin and Ki-67 proteins. We also demonstrated that this pathway could be triggered by microenvironment signals like CD40 ligand/interleukin-4 and, more importantly, that this regulatory loop is also present in lymph nodes from progressive unmutated patients. Altogether, these results underline the key role of PI3K/AKT pathway in the generation of the CLL proliferative pool and provide additional rationale for the usage of PI3K inhibitors.

Intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma in patients undergoing liver transplantation: a Spanish matched cohort multicenter study.

OBJECTIVE: To evaluate the outcome of patients with hepatocellular-cholangiocarcinoma (HCC-CC) or intrahepatic cholangiocarcinoma (I-CC) on pathological examination after liver transplantation for HCC. BACKGROUND: Information on the outcome of cirrhotic patients undergoing a transplant for HCC and with a diagnosis of HCC-CC or I-CC by pathological study is limited. METHODS: Multicenter, retrospective, matched cohort 1:2 study. STUDY GROUP: 42 patients undergoing a transplant for HCC and with a diagnosis of HCC-CC or I-CC by pathological study; and control group: 84 patients with a diagnosis of HCC. I-CC subgroup: 27 patients compared with 54 controls; HCC-CC subgroup: 15 patients compared with 30 controls. Patients were also divided according to the preoperative tumor size and number: uninodular tumors 2 cm or smaller and multinodular or uninodular tumors 2 cm or larger. Median follow-up: 51 (range, 3-142) months. RESULTS: The 1-, 3-, and 5-year actuarial survival rate differed between the study and control groups (83%, 70%, and 60% vs 99%, 94%, and 89%, respectively; P < 0.001). Differences were found in 1-, 3-, and 5-year actuarial survival rates between the I-CC subgroup and their controls (78%, 66%, and 51% vs 100%, 98%, and 93%; P < 0.001), but no differences were observed between the HCC-CC subgroup and their controls (93%, 78%, and 78% vs 97%, 86%, and 86%; P = 0.9). Patients with uninodular tumors 2 cm or smaller in the study and control groups had similar 1-, 3-, and 5-year survival rate (92%, 83%, 62% vs 100%, 80%, 80%; P = 0.4). In contrast, patients in the study group with multinodular or uninodular tumors larger than 2 cm had worse 1-, 3-, and 5-year survival rates than their controls (80%, 66%, and 61% vs 99%, 96%, and 90%; P < 0.001). CONCLUSIONS: Patients with HCC-CC have similar survival to patients undergoing a transplant for HCC. Preoperative diagnosis of HCC-CC should not prompt the exclusion of these patients from transplant option.

"Very early" intrahepatic cholangiocarcinoma in cirrhotic patients: should liver transplantation be reconsidered in these patients?

A retrospective cohort multicenter study was conducted to analyze the risk factors for tumor recurrence after liver transplantation (LT) in cirrhotic patients found to have an intrahepatic cholangiocarcinoma (iCCA) on pathology examination. We also aimed to ascertain whether there existed a subgroup of patients with single tumors ≤2 cm ("very early") in which results after LT can be acceptable. Twenty-nine patients comprised the study group, eight of whom had a "very early" iCCA (four of them incidentals). The risk of tumor recurrence was significantly associated with larger tumor size as well as larger tumor volume, microscopic vascular invasion and poor degree of differentiation. None of the patients in the "very early" iCCA subgroup presented tumor recurrence compared to 36.4% of those with single tumors >2 cm or multinodular tumors, p = 0.02. The 1-, 3- and 5-year actuarial survival of those in the "very early" iCCA subgroup was 100%, 73% and 73%, respectively. The present is the first multicenter attempt to ascertain the risk factors for tumor recurrence in cirrhotic patients found to have an iCCA on pathology examination. Cirrhotic patients with iCCA ≤2 cm achieved excellent 5-year survival, and validation of these findings by other groups may change the current exclusion of such patients from transplant programs.

Cirugía de intervalo: citorreducción óptima en cáncer de ovario estadio III / Interval surgery: optimums cytoreduction in ovarian cancer stage III

Demostrar que la cirugía de intervalo constituye una opción terapéutica efectiva en el aumento de la resecabilidad tumoral, mejorando la sobrevida de aquellas pacientes con tumores epiteliales de ovario clasificados como estadio III y catalogados como "no resecables". Estudio retrospectivo y descriptivo de las pacientes pertenecientes al servicio de ginecología del Hospital Oncológico "Padre Machado" con el diagnóstico de tumor epitelial de ovario clasificados como estadio III, incluidos en un protocolo de cirugía de intervalo, en el período septiembre 2002- septiembre 2007. Fueron identificadas 13 pacientes. El esquema de quimioterapia utilizado en todos los casos fue el de paclitaxel a dosis de 175mg/m² y carboblatino 5ABC, con una media de 4,46 ciclos. Se estableció una respuesta posterior a la quimioterapia primaria mayor al 50 por ciento 76,92 por ciento de los pacientes. La cirugía de intervalo aumenta el porcentaje de resecabilidad y disminuye el porcentaje de complicaciones posoperatorias, no evidenciándose beneficios estadísticamente significativos en términos de aumento de la sobrevida libre de enfermedad.

To demonstrate that interval debulking surgery constitutes an effective therapeutic option in the increase of the tumor like resected, improving the over life of those patients with epithelial tumors of ovary classified III stage, catalogued like “none resected”. Retrospective and descriptive study of the patients that assisted the service of gynecology of the Oncology Hospital “Padre Machado” with the diagnosis of epithelial tumor of ovary III stage, included in protocol interval debulking surgery, during the period September 2002-September 2007. 13 patients were identified. The scheme of chemotherapy used in all the cases was paclitaxel at dose of 175mg/m² and carboblatin 5ABC, with a media of 4.46 cycles. An answer greater than 50 % was settled down subsequent to the primary chemotherapy in a 76.92 % of the patients. The interval debulking surgery increases the percentage of respectability and diminishes the percentage of postoperative complications, not demonstrating itself significant benefits in terms of increase in the free disease period.

Mammary hamartoma.

INTRODUCTION: Mammary hamartomas are rare benign breast lumps. They are usually painless, wellcircumscribed, mobile and with no adherence to skin or muscle, composed of varying amounts of fat, glandular and fibrous tissue. Mammary hamartoma has been classically considered as an underdiagnosed pathology, but with the increasing use of diagnostic procedures in breast tumours, the number of hamartomas has increased in the last years. Because there is no distinct pathological feature, a correlation with the clinical findings and image techniques is necessary in order to achieve a correct diagnosis of the pathology. MATERIALS AND METHODS: The clinicopathological features of 8 mammary hamartomas are reported here. RESULTS: The patients are ranged in age from 34 to 67 years. The initial manifestation was in all cases a well-circumscribed, soft, palpable breast lump. Mammography was performed in all patients. Other diagnostic procedures used in the diagnosis were Ultrasound, Fine Needle Aspiration Cytology and Needle Core Biopsy. Treatment was tumorectomy. We describe a case of recurrence after excision of the lump in a more aggressive histological form and one patient who presented the coexistence of a mammary hamartoma and an invasive ductal carcinoma. CONCLUSION: Mammary hamartoma is an uncommon breast tumour. It is necessary the correlation between pathology and clinical and radiological findings. We express our management plan for these lesions.

Inflammation and perforation of a solitary diverticulum of the cecum. A report of 5 cases and literature review.

Solitary diverticulum of the cecum is a benign condition uncommon in the Western world, and with a higher incidence in Asian population. They are usually asymptomatic, and manifest clinically only with complications such as inflammation, perforation, or bleeding. They are a rare cause of acute abdominal pain, clinically similar to acute appendicitis, with tenderness in the right lower quadrant, fever, and leukocytosis. In spite of the information provided by ultrasonography or CT scans, a correct preoperative diagnosis is still difficult to reach, and is usually arrived at in the operating theater; differentiation from a neoplasm may be also sometimes complicated, and a wide surgical resection is usually required for such cases. We report on 5 cases of inflammation and perforation of a solitary cecal diverticulum, and perform a literature review.

Simultaneous determination of cefepime and grepafloxacin in human urine by high-performance liquid chromatography.

A liquid chromatographic method with UV detection for simultaneous determination of cefepime and grepafloxacin has been developed. The method uses a C18 column, equipped with a pre-column of the same material, and acetonitrile-0.1 M phosphoric acid/sodium hydroxide buffer (pH 3.0)-0.01 M n-octylamine (pH 3.0) as mobile phase in gradient mode. Mobile flow rate and sample volume injected were 1.3 mL min(-1) and 20 microL, respectively. Detection wavelengths were 259 nm for cefepime and 278 nm for grepafloxacin. The retention times were 4.03 min for cefepime and 8.85 min for grepafloxacin, with detection limits of 1.0 and 1.1 microg mL(-1), respectively. The method was applied to the determination of both antibiotics in spiked samples of human urine.

Breast metastasis of primary colon cancer.

Metastatic tumors to the breast from colon adenocarcinoma are very rare. They are usually indicative of disseminated disease, and the prognosis is poor. Generally, radical operation should be avoided unless needed for palliation. This case report described a patient with breast metastasis from colon adenocarcinoma treated by simple mastectomy.

Adsorptive stripping voltammetric determination of cefepime at the mercury electrode in human urine and cerebrospinal fluid, and differential pulse polarographic determination in serum.

The cephalosporin cefepime has been studied by adsorptive stripping voltammetric on the hanging mercury drop electrode, followed by linear sweep voltammetry (staircase). The adsorptive stripping response was evaluated with respect to preconcentration dependence and other variables. The drug is strongly adsorbed in acid media, with maximum adsorption at pH 5.8. The detection limit found was 4.8 x 10(-10) M, with 120-s preconcentration. The relative standard deviation at the 10(-7) M level was 0.93%. This method was applied to the determination of cefepime in human urine and cerebrospinal fluid. Differential pulse polarography has been applied to determination in human serum.

Wavelet transform analysis of heart rate variability during myocardial ischaemia.

Analysis of heart rate variability (HRV) is a valuable, non-invasive method for quantifying autonomic cardiac control in humans. Frequency-domain analysis of HRV involving myocardial ischaemic episodes should take into account its non-stationary behaviour. The wavelet transform is an alternative tool for the analysis of non-stationary signals. Fourteen patients have been analysed, ranging from 40 to 64 years old and selected from the European Electrocardiographic ST-T Database (ESDB). These records contain 33 ST episodes, according to the notation of the ESDB, with durations of between 40s and 12 min. A method for analysing HRV signals using the wavelet transform was applied to obtain a time-scale representation for very low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands using the orthogonal multiresolution pyramidal algorithm. The design and implementation using fast algorithms included a specially adapted decomposition quadrature mirror filter bank for the frequency bands of interest. Comparing a normality zone against the ischaemic episode in the same record, increases in LF (0.0112 +/- 0.0101 against 0.0175 +/- 0.0208 s2 Hz(-1); p<0.1) and HF (0.0011 +/- 0.0008 against 0.00 17 +/- 0.0020 s2 Hz(-1); p<0.05) were obtained. The possibility of using these indexes to develop an ischaemic-episode classifier was also tested. Results suggest that wavelet analysis provides useful information for the assessment of dynamic changes and patterns of HRV during myocardial ischaemia.

Randomized comparison of efficacy of cooled tip catheter ablation of atrial flutter: anatomic versus electrophysiological complete isthmus block.

There is a subset of patients with failed ablation of the cavotricuspid isthmus (CTI) using standard catheters and with 10% of the patients having recurrences. The purpose of this study was to compare the cooled and standard ablation with regard to acute successful electrophysiological achievement of bidirectional isthmus block and the subacute anatomic characteristics of the lesions. This randomized, experimental study compares the effects of ablation on the isthmus using a cooled catheter with those of a standard ablation catheter in 16 pigs. In 12 animals, CTI block was achieved after ablation (8/8 cooled and 4/8 standard). In two animals, it was not possible to achieve complete isthmus block and two had persistent slow conduction (all four using the standard catheter). After 1 week, the animals were slaughtered. The size of the lesion was greater with the irrigated tip catheters. Transmural lesions were found in 14 animals. A complete line of anatomic isthmus block was not documented after thefirst line in six animals, four with the standard and two with the cooled catheter. A conduction block was never present across gaps > or = 5 mm. In conclusion cooled catheters achieved a complete line of electrophysiological and anatomical block in a significantly higher percentage than the standard catheters.

An essential role for ARF6-regulated membrane traffic in adherens junction turnover and epithelial cell migration.

We describe a novel role for the ARF6 GTPase in the regulation of adherens junction (AJ) turnover in MDCK epithelial cells. Expression of a GTPase-defective ARF6 mutant, ARF6(Q67L), led to a loss of AJs and ruffling of the lateral plasma membrane via mechanisms that were mutually exclusive. ARF6-GTP-induced AJ disassembly did not require actin remodeling, but was dependent on the internalization of E-cadherin into the cytoplasm via vesicle transport. ARF6 activation was accompanied by increased migratory potential, and treatment of cells with hepatocyte growth factor (HGF) induced the activation of endogenous ARF6. The effect of ARF6(Q67L) on AJs was specific since ARF6 activation did not perturb tight junction assembly or cell polarity. In contrast, dominant-negative ARF6, ARF6(T27N), localized to AJs and its expression blocked cell migration and HGF-induced internalization of cadherin-based junctional components into the cytoplasm. Finally, we show that ARF6 exerts its role downstream of v-Src activation during the disassembly of AJs. These findings document an essential role for ARF6- regulated membrane traffic in AJ disassembly and epithelial cell migration.