Pattern and timing of the coronary sinus activation to guide rapid diagnosis of atrial tachycardia after atrial fibrillation ablation

BACKGROUND Atrial tachycardias (AT) during or after ablation of atrial fibrillation frequently pose a diagnostic challenge. We hypothesized that both the patterns and the timing of coronary sinus (CS) activation could facilitate AT mapping. METHODS AND RESULTS A total of 140 consecutive postpersistent atrial fibrillation ablation patients with sustained AT were investigated by conventional mapping. CS activation pattern was defined as chevron or reverse chevron when the activations recorded on both the proximal and the distal CS dipoles were latest or earliest, respectively. The local activation of mid-CS was timed with reference to Ppeak-Ppeak (P-P) interval in lead V1. A ratio, mid-CS activation time to AT cycle length, was computed. Of 223 diagnosed ATs, 124 were macroreentrant (56%) and 99 were centrifugal (44%). When CS activation was chevron/reverse chevron (n=44; 20%), macroreentries were mostly roof dependent. With reference to P-P interval, mid-CS activation timing showed specific consistency for peritricuspid and perimitral AT. Proximal to distal CS activation pattern and mid-CS activation at 50% to 70% of the P-P interval (n=30; 13%) diagnosed peritricuspid AT with 81% sensitivity and 89% specificity. Distal to proximal CS activation and mid-CS activation at 10% to 40% of the P-P interval (n=44; 20%) diagnosed perimitral AT with 88% sensitivity and 75% specificity. CONCLUSIONS The analysis of the patterns and timing of CS activation provides a rapid stratification of most likely macroreentrant ATs and points toward the likely origin of centrifugal ATs. It can be included in a stepwise diagnostic approach to rapidly select the most critical mapping maneuvers.

Characterization of the 9L gliosarcoma implanted in the Fischer rat: an orthotopic model for a grade IV brain tumor.

Among rodent models for brain tumors, the 9L gliosarcoma is one of the most widely used. Our 9L-European Synchrotron Radiation Facility (ESRF) model was developed from cells acquired at the Brookhaven National Laboratory (NY, USA) in 1997 and implanted in the right caudate nucleus of syngeneic Fisher rats. It has been largely used by the user community of the ESRF during the last decade, for imaging, radiotherapy, and chemotherapy, including innovative treatments based on particular irradiation techniques and/or use of new drugs. This work presents a detailed study of its characteristics, assessed by magnetic resonance imaging (MRI), histology, immunohistochemistry, and cytogenetic analysis. The data used for this work were from rats sampled in six experiments carried out over a 3-year period in our lab (total number of rats = 142). The 9L-ESRF tumors were induced by a stereotactic inoculation of 10(4) 9L cells in the right caudate nucleus of the brain. The assessment of vascular parameters was performed by MRI (blood volume fraction and vascular size index) and by immunostaining of vessels (rat endothelial cell antigen-1 and type IV collagen). Immunohistochemistry and regular histology were used to describe features such as tumor cell infiltration, necrosis area, nuclear pleomorphism, cellularity, mitotic characteristics, leukocytic infiltration, proliferation, and inflammation. Moreover, for each of the six experiments, the survival of the animals was assessed and related to the tumor growth observed by MRI or histology. Additionally, the cytogenetic status of the 9L cells used at ESRF lab was investigated by comparative genomics hybridization analysis. Finally, the response of the 9L-ESRF tumor to radiotherapy was estimated by plotting the survival curves after irradiation. The median survival time of 9L-ESRF tumor-bearing rats was highly reproducible (19-20 days). The 9L-ESRF tumors presented a quasi-exponential growth, were highly vascularized with a high cellular density and a high proliferative index, accompanied by signs of inflammatory responses. We also report an infiltrative pattern which is poorly observed on conventional 9 L tumor. The 9L-ESRF cells presented some cytogenetic specificities such as altered regions including CDK4, CDKN2A, CDKN2B, and MDM2 genes. Finally, the lifespan of 9L-ESRF tumor-bearing rats was enhanced up to 28, 35, and 45 days for single doses of 10, 20, and 2 × 20 Gy, respectively. First, this report describes an animal model that is used worldwide. Second, we describe few features typical of our model if compared to other 9L models worldwide. Altogether, the 9L-ESRF tumor model presents characteristics close to the human high-grade gliomas such as high proliferative capability, high vascularization and a high infiltrative pattern. Its response to radiotherapy demonstrates its potential as a tool for innovative radiotherapy protocols.

AN ELECTROPHYSIOLOGICAL ANALYSIS OF THE AMYGDALOID AND SUBICULAR PROJECTIONS TO THE VENTROMEDIAL NUCLEUS OF THE HYPOTHALAMUS IN THE RABBIT

Electrophysiological experiments were performed on 96 male New Zealand white rabbits, anesthetized with urethane. Glass electrodes, filled with 2M NaCl, were used for microstimulation of three fiber pathways projecting from "limbic" centers to the ventromedial nucleus of the hypothalamus (VMH). Unitary and field potential recordings were made in the VMH after stimulation.^ Stimulation of the lateral portion of the fimbria, which carries fibers from the ventral subiculum of the hippocampal formation, evokes predominantly an inhibition of neurons medially in the VMH, and excitation of neurons located laterally.^ Stimulation of the dorsal portion of the stria terminalis, which carries fibers from the cortical nucleus of the amygdala, also produces predominantly an inhibition of cells medially and excitation laterally.^ Stimulation of the ventral component of the stria terminalis, which carries fibers from the medial nucleus of the amygdala, evokes excitation of cell medially, with little or no response seen laterally.^ Cells recorded medially in the VMH received convergent inputs from each of the three fiber systems: inhibition from fimbria and dorsal stria stimulation, excitation from ventral stria stimulation.^ The excitatory unitary responses recorded medially to ventral stria stimulation and laterally to fimbria and dorsal stria stimulation were subjected to a series of threshold stimulus intensities. From these tests it was determined that each of these three projections terminates monosynaptically on VMH neurons.^ The evidence for convergence upon single VMH neurons of projections from the amygdala and the hippocampal formation suggests this area of the brain to be important for integration of information from these two limbic centers. The VMH has been implied in a number of behavioral states: eating, reproduction, defense and aggression; it has further been linked to control of the anterior pituitary. These data provide a functional circuit through which the amygdaloid complex and the hippocampal formation can channel information from higher cortical centers into a hypothalamic area capable of coordinating behavioral and hormonal responses. ^

Doppler sonography of the medial arterial blood supply to the coxofemoral joints of 36 medium to large breed dogs and its relationship with radiographic signs of joint disease.

The medial arterial supply to 68 of the 72 coxofemoral joints of 36 medium to large breed dogs was examined ultrasonographically. The medial circumflex femoral artery and three branches were identified; the artery and its transverse branch were identified in all 68 joints, and the deep branch was identified in 61 joints, and the ascending branch was identified in 63. However, the acetabular and obturator branches were not identified. The pulsatility index, the mean velocity and the peak systolic velocity of the medial circumflex femoral artery were determined and associated with a radiographic score of degenerative coxofemoral joint disease and a lath distraction index (LDI). In joints with a LDI greater than 0.35, the pulsatility index was significantly lower (P=0.023) and its mean velocity was higher (P=0.005). However, no significant associations were observed in individual dogs when the measurements in both joints were taken into account.

ACL reconstruction with physiological graft tension by intraoperative adjustment of the anteroposterior translation to the uninjured contralateral knee.

PURPOSE Fixation of anterior cruciate ligament (ACL) substitutes with non-physiological anteroposterior translation (APT) worsens outcome. The aim was to present a technique for physiological APT adjustment of the transplant in ACL reconstruction and its outcome at midterm. METHODS In a consecutive series of 28 patients (age 32 ± 11 years, 24 male), chronic ACL deficiency was treated by bone-patella-tendon-bone reconstruction. Transplant APT was adjusted to that of the contralateral uninjured ACL, measured 3, 6, and 12 months postoperatively using the Rolimeter. At a median follow-up of 5.3 years (3-8 years), 82% of the patients were re-evaluated with APT measurement and using IKDC-, Tegner-, Lysholm-Scores, conventional radiographs and MRI. RESULTS No differences in APT (mean ± SD) between uninjured and reconstructed knees were observed after adjustment (6 ± 1 versus 6 ± 1 mm, n.s.). Three months postoperatively, a statistically significant increase in APT (7 ± 1 mm) and a further increase at midterm (9 ± 2 mm) were observed. Patients scored "normal" or "nearly normal", respectively, in 79% (IKDC) and 4 (3-9) points (Tegner; median, range) or 89 ± 9 points (Lysholm; mean ± SD). Radiological evaluation showed no, minimal or moderate joint degeneration in 5, 20 and 75% of patients, respectively. MRI confirmed intact ACL transplants in all patients. CONCLUSION ACL reconstruction using the presented technique was considered successful, as patients did not suffer from subjective instability, radiographic analysis did not provide evidence for graft rupture at midterm. However, APT increase and occurrence of degenerative changes in reconstructed knees at the midterm might not be prevented even by restoration of a physiological APT in ACL reconstruction. The Rolimeter can be used for quick and easy intraoperative indirect control of the applied tension to the ACL transplant by measuring the APT to obtain physiological tensioning resulting in a satisfying outcome at midterm. LEVEL OF EVIDENCE IV.

Comparison of 3D kinetic and hydrodynamic models to ROSINA-COPS measurements of the neutral coma of 67P/Churyumov-Gerasimenko

67P/Churyumov-Gerasimenko (67P) is a Jupiter-family comet and the object of investigation of the European Space Agency mission Rosetta. This report presents the first full 3D simulation results of 67P’s neutral gas coma. In this study we include results from a direct simulation Monte Carlo method, a hydrodynamic code, and a purely geometric calculation which computes the total illuminated surface area on the nucleus. All models include the triangulated 3D shape model of 67P as well as realistic illumination and shadowing conditions. The basic concept is the assumption that these illumination conditions on the nucleus are the main driver for the gas activity of the comet. As a consequence, the total production rate of 67P varies as a function of solar insolation. The best agreement between the model and the data is achieved when gas fluxes on the night side are in the range of 7% to 10% of the maximum flux, accounting for contributions from the most volatile components. To validate the output of our numerical simulations we compare the results of all three models to in situ gas number density measurements from the ROSINA COPS instrument. We are able to reproduce the overall features of these local neutral number density measurements of ROSINA COPS for the time period between early August 2014 and January 1 2015 with all three models. Some details in the measurements are not reproduced and warrant further investigation and refinement of the models. However, the overall assumption that illumination conditions on the nucleus are at least an important driver of the gas activity is validated by the models. According to our simulation results we find the total production rate of 67P to be constant between August and November 2014 with a value of about 1 × 10²⁶ molecules s⁻¹.

Hemodynamics analyses in treated and untreated carotid arteries of the same patient: A preliminary study based on three patient cases

Carotid atherosclerotic disease is highly related to cerebrovascular events. Carotid endarterectomy is the common operation method to treat this disease. In this study, hemodynamics analyses are performed on the carotid arteries in three patients, whose right carotid artery had been treated by carotid endarterectomy and the left carotid artery remained untreated. Flow and loading conditions are compared between these treated and untreated carotid arteries and evaluation of the operative results is discussed. Patient-specific models are reconstructed from MDCT data. Intraoperative ultrasound flow measurements are performed on the treated carotid arteries and the obtained data are used as the boundary conditions of the models and the validations of the computational results. Finite volume method is employed to solve the transport equations and the flow and loading conditions of the models are reported. The results indicate that: (i) in two of the three patients, the internal-to-external flow rate ratio in the untreated carotid artery is larger than that in the treated one, and the average overall flow split ratio by summing up the data of both the left and right carotid arteries is about 2.15; (ii) in the carotid bulb, high wall shear stress occurs at the bifurcation near the external carotid artery in all of the cases without hard plaques; (iii) the operated arteries present low time-averaged wall shear stress at the carotid bulb, especially for the treated arteries with patch technique, indicating the possibility of the recurrence of stenosis; (iv) high temporal gradient of wall shear stress (>35 Pa/s) is shown in the narrowing regions along the vessels; and (v) in the carotid arteries without serious stenosis, the maximum velocity magnitude during mid-diastole is 32~37% of that at systolic peak, however, in the carotid artery with 50% stenosis by hard plaques, this value is nearly doubled (64%). The computational work quantifies flow and loading distributions in the treated and untreated carotid arteries of the same patient, contributing to evaluation of the operative results and indicating the recurrent sites of potential atheromatous plaques.

THE APPLICATION OF PATH ANALYSIS TO ASSESSMENT OF IRON NUTRITIONAL STATUS IN MAN

Path analysis has been applied to components of the iron metabolic system with the intent of suggesting an integrated procedure for better evaluating iron nutritional status at the community level. The primary variables of interest in this study were (1) iron stores, (2) total iron-binding capacity, (3) serum ferritin, (4) serum iron, (5) transferrin saturation, and (6) hemoglobin concentration. Correlation coefficients for relationships among these variables were obtained from published literature and postulated in a series of models using measures of those variables that are feasible to include in a community nutritional survey. Models were built upon known information about the metabolism of iron and were limited by what had been reported in the literature in terms of correlation coefficients or quantitative relationships. Data were pooled from various studies and correlations of the same bivariate relationships were averaged after z- transformations. Correlation matrices were then constructed by transforming the average values back into correlation coefficients. The results of path analysis in this study indicate that hemoglobin is not a good indicator of early iron deficiency. It does not account for variance in iron stores. On the other hand, 91% of the variance in iron stores is explained by serum ferritin and total iron-binding capacity. In addition, the magnitude of the path coefficient (.78) of the serum ferritin-iron stores relationship signifies that serum ferritin is the most important predictor of iron stores in the proposed model. Finally, drawing upon known relations among variables and the amount of variance explained in path models, it is suggested that the following blood measures should be made in assessing community iron deficiency: (1) serum ferritin, (2) total iron-binding capacity, (3) serum iron, (4) transferrin saturation, and (5) hemoglobin concentration. These measures (with acceptable ranges and cut-off points) could make possible the complete evaluation of all three stages of iron deficiency in those persons surveyed at the community level. ^

In search of the ox : Gateways to understanding human individuation through guidance

Este ensayo sintetiza varias aristas teóricas prácticas dirigidas a una de las decisiones personales más importantes en todo ser humano, el camino del autoconocimiento. Siempre y cuando se reflejen esas necesidades intrínsecas del ser, el hombre contemporáneo está descubriendo que en la satisfacción de los requerimientos materiales, finalmente no se encuentra ni la felicidad, ni la paz verdadera. En medio de este imaginario, el rol del Orientador está en su capacidad de guía fundamentado en unos principios y valores que garanticen que ese camino sea hallado, puesto que su gran compromiso consigo mismo y con los demás es precisamente acompañar en el descubrimiento de los talentos y potencialidades de ese sujeto para aprovechar su genialidad e innatas formas de normal crecimiento hacia la felicidad y armonía. Entre los caminos están los estudiados por un sinnúmero de teóricos expertos en la existencia humana como Ortega y Gasset, Sabater, Jung, Heidegger, Gadamer, Luckmann, Habermas, Bauman, Binswanger. Es un apasionante recorrido por estos análisis motivantes y sobre todo retadores.

Vocational and occupational counsseling: a strategy of preventive intervention directed to Young men and women from the interior of the province of Buenos Aires

This work belongs to one of the activities that are carried out in the Vocational and Occupational Guidance Center (V.O.G.C.) of the Faculty of Humanities and Educational Sciences at the L.P.N.U. In the year 1994 the Vocational/Occupational Guidance Programme for Municipalities was created, destined for work with adolescents who are attending their last year at secondary schools in the interior of the Province of Buenos Aires . The Programme aims at fostering the development of spaces for reflection related to the educational/working projects of the adolescents who are close to entering university. The proposal is based on the methodology of work groups, in the journeys preoccupations are sheared, the worries and fears experienced by the students are shared with their hosts, possibilities are used as ground for construction, dealing both with aspects of their current situation and their future possibilities. From the analysis of the group productions collected throughout these years, we have developed a student's profile that - although it resembles the one obtained from local adolescents- adds new questions and points of view, thus increasing the complexity of the balance of forces related to the question of having to make a choice.

In search of the ox : Gateways to understanding human individuation through guidance

Este ensayo sintetiza varias aristas teóricas prácticas dirigidas a una de las decisiones personales más importantes en todo ser humano, el camino del autoconocimiento. Siempre y cuando se reflejen esas necesidades intrínsecas del ser, el hombre contemporáneo está descubriendo que en la satisfacción de los requerimientos materiales, finalmente no se encuentra ni la felicidad, ni la paz verdadera. En medio de este imaginario, el rol del Orientador está en su capacidad de guía fundamentado en unos principios y valores que garanticen que ese camino sea hallado, puesto que su gran compromiso consigo mismo y con los demás es precisamente acompañar en el descubrimiento de los talentos y potencialidades de ese sujeto para aprovechar su genialidad e innatas formas de normal crecimiento hacia la felicidad y armonía. Entre los caminos están los estudiados por un sinnúmero de teóricos expertos en la existencia humana como Ortega y Gasset, Sabater, Jung, Heidegger, Gadamer, Luckmann, Habermas, Bauman, Binswanger. Es un apasionante recorrido por estos análisis motivantes y sobre todo retadores.

Vocational and occupational counsseling: a strategy of preventive intervention directed to Young men and women from the interior of the province of Buenos Aires

This work belongs to one of the activities that are carried out in the Vocational and Occupational Guidance Center (V.O.G.C.) of the Faculty of Humanities and Educational Sciences at the L.P.N.U. In the year 1994 the Vocational/Occupational Guidance Programme for Municipalities was created, destined for work with adolescents who are attending their last year at secondary schools in the interior of the Province of Buenos Aires . The Programme aims at fostering the development of spaces for reflection related to the educational/working projects of the adolescents who are close to entering university. The proposal is based on the methodology of work groups, in the journeys preoccupations are sheared, the worries and fears experienced by the students are shared with their hosts, possibilities are used as ground for construction, dealing both with aspects of their current situation and their future possibilities. From the analysis of the group productions collected throughout these years, we have developed a student's profile that - although it resembles the one obtained from local adolescents- adds new questions and points of view, thus increasing the complexity of the balance of forces related to the question of having to make a choice.

In search of the ox : Gateways to understanding human individuation through guidance

Este ensayo sintetiza varias aristas teóricas prácticas dirigidas a una de las decisiones personales más importantes en todo ser humano, el camino del autoconocimiento. Siempre y cuando se reflejen esas necesidades intrínsecas del ser, el hombre contemporáneo está descubriendo que en la satisfacción de los requerimientos materiales, finalmente no se encuentra ni la felicidad, ni la paz verdadera. En medio de este imaginario, el rol del Orientador está en su capacidad de guía fundamentado en unos principios y valores que garanticen que ese camino sea hallado, puesto que su gran compromiso consigo mismo y con los demás es precisamente acompañar en el descubrimiento de los talentos y potencialidades de ese sujeto para aprovechar su genialidad e innatas formas de normal crecimiento hacia la felicidad y armonía. Entre los caminos están los estudiados por un sinnúmero de teóricos expertos en la existencia humana como Ortega y Gasset, Sabater, Jung, Heidegger, Gadamer, Luckmann, Habermas, Bauman, Binswanger. Es un apasionante recorrido por estos análisis motivantes y sobre todo retadores.

Vocational and occupational counsseling: a strategy of preventive intervention directed to Young men and women from the interior of the province of Buenos Aires

This work belongs to one of the activities that are carried out in the Vocational and Occupational Guidance Center (V.O.G.C.) of the Faculty of Humanities and Educational Sciences at the L.P.N.U. In the year 1994 the Vocational/Occupational Guidance Programme for Municipalities was created, destined for work with adolescents who are attending their last year at secondary schools in the interior of the Province of Buenos Aires . The Programme aims at fostering the development of spaces for reflection related to the educational/working projects of the adolescents who are close to entering university. The proposal is based on the methodology of work groups, in the journeys preoccupations are sheared, the worries and fears experienced by the students are shared with their hosts, possibilities are used as ground for construction, dealing both with aspects of their current situation and their future possibilities. From the analysis of the group productions collected throughout these years, we have developed a student's profile that - although it resembles the one obtained from local adolescents- adds new questions and points of view, thus increasing the complexity of the balance of forces related to the question of having to make a choice.

Reconstruction of sea-surface conditions at middle to high latitudes of the Northern Hemisphere

A new calibration database of census counts of organic-walled dinoflagellate cyst (dinocyst) assemblages has been developed from the analyses of surface sediment samples collected at middle to high latitudes of the Northern Hemisphere after standardisation of taxonomy and laboratory procedures. The database comprises 940 reference data points from the North Atlantic, Arctic and North Pacific oceans and their adjacent seas, including the Mediterranean Sea, as well as epicontinental environments such as the Estuary and Gulf of St. Lawrence, the Bering Sea and the Hudson Bay. The relative abundance of taxa was analysed to describe the distribution of assemblages. The best analogue technique was used for the reconstruction of Last Glacial Maximum (LGM) sea-surface temperature and salinity during summer and winter, in addition to sea-ice cover extent, at sites from the North Atlantic (n=63), Mediterranean Sea (n=1) and eastern North Pacific (n=1). Three of the North Atlantic cores, from the continental margin of eastern Canada, revealed a barren LGM interval, probably because of quasi-permanent sea ice. Six other cores from the Greenland and Norwegian seas were excluded from the compilation because of too sparse assemblages and poor analogue situation. At the remaining sites (n= 54), relatively close modern analogues were found for most LGM samples, which allowed reconstructions. The new LGM results are consistent with previous reconstructions based on dinocyst data, which show much cooler conditions than at present along the continental margins of Canada and Europe, but sharp gradients of increasing temperature offshore. The results also suggest low salinity and larger than present contrasts in seasonal temperatures with colder winters and more extensive sea-ice cover, whereas relatively warm conditions may have prevailed offshore in summer. From these data, we hypothesise low thermal inertia in a shallow and low-density surface water layer.