Prevalencia de déficit atencional en estudiantes de medicina de la Pontificia Universidad Católica de Chile / Prevalence of attention deficit disorder in Chilean medical students

Introducción: Se ha reconocido que el déficit atencional (DA) persiste en la adultez en un 50-70 por ciento de los casos, sin embargo, existe escasa investigación respecto de prevalencia e impacto en este grupo etáreo. Nos proponemos conocer la prevalencia de DA en estudiantes de medicina chilenos. Metodología: Se utilizó encuesta sociodemográfica, cuestionario de salud mental de Goldbergy escala ASRS v.1.1. Resultados: Un 22,9 por ciento resultó positivo para síntomas mentales, y un 31 por ciento lo fue para DA según ASRS, en contraste con un 7 por ciento de autorreporte de diagnóstico previo de DA. No hubo correlación significativa entre diagnóstico de DA por escala ASRS con sexo, edad ni lugar de procedencia, pero si la hubo con Goldberg positivo, antecedente de diagnóstico psiquiátrico previo y diagnóstico previo de DA. Discusión: La medición de DA probablemente está sesgada por variables emocionales y derivadas de la alta demanda académica y la expectativa de rendimiento de los alumnos. Pensamos que la prevalencia real de DA en estudiantes de medicina debiera estar cercana al 7% reportado por los alumnos y en línea con las publicaciones internacionales. Este es el primer estudio nacional en este tema y obliga a plantear otra modalidad de investigación.

Introduction: It has been recognized that the attention deficit (AD) persists into adulthood in 50-70% of cases, however, there is little research on prevalence and impact on this age group. We propose to determine the prevalence of AD in Chilean medical students. Methods: We used demographic survey, Goldberg mental health questionnaire and ASRS v.1.1. scale. Results: 22.9% were positive for mental symptoms, and 31% was for AD measured with ASRS, compared with 7% of self-reported prior diagnosis of AD. There was no significant correlation between diagnosis of AD by ASRS scale with sex, age and place of origin, but if there was one with positive Goldberg, history of previous psychiatric diagnosis and previous diagnosis of AD. Discussion: The measurement of DA is probably biased by emotional variables derived from the high demand and the expectation of academic achievement of students. We think that the true prevalence of AD in medical students should be close to 7% reported by students and in line with international publications. This is the first Chilean study on this topic and it forces to raise other research modalities.

Direct k-space mapping of the electronic structure in an oxide-oxide interface.

The interface between LaAlO(3) and SrTiO(3) hosts a two-dimensional electron system of itinerant carriers, although both oxides are band insulators. Interface ferromagnetism coexisting with superconductivity has been found and attributed to local moments. Experimentally, it has been established that Ti 3d electrons are confined to the interface. Using soft x-ray angle-resolved resonant photoelectron spectroscopy we have directly mapped the interface states in k space. Our data demonstrate a charge dichotomy. A mobile fraction contributes to Fermi surface sheets, whereas a localized portion at higher binding energies is tentatively attributed to electrons trapped by O vacancies in the SrTiO(3). While photovoltage effects in the polar LaAlO(3) layers cannot be excluded, the apparent absence of surface-related Fermi surface sheets could also be fully reconciled in a recently proposed electronic reconstruction picture where the built-in potential in the LaAlO(3) is compensated by surface O vacancies serving also as a charge reservoir.

José Juan Bruner (1825-1899): una estrella fugaz en la historia de la psiquiatría chilena / The contribution of Jose Juan Bruner to Chilean psychiatry

The contribution of Dr. Bruner to psychology and psychiatry is largely unknown. This is a summary of the ideas proposed in his "Medical-Psychological Monograph" from 1857, that was written after a case of a possibly possessed woman from Santiago. In this work Dr. Bruner discards the spirit-brain duality, proposes a functional morphology of the brain, recognizes the importance of remote history taking when interviewing patients, proposes a theory for self-formation and the risks of self-fragmentation. He proposes that the case of the woman corresponds to a brain disease, opposing the thought of an ovarian and uterine origin. He proposes a hypothesis of the psychogenic origin of the disease, the importance of what happened during dreams and beyond the conscience of the patient. Many of his ideas preceded by decades those of Charcot and Freud, but they have not had a proper recognition.

Abuso y dependencia de internet: la epidemia y su controversia / Internet abuse and dependence: the epidemic and its controversy

Background: Since Internet made its first appearance for the general public, and its thereafter growth, different emerging health issues have been described. The discussion has taken place not only in the mass media, but also in the academy, initially with case reports of abuse and dependence, and now that it has been considered as a new diagnosis in the not yet finished DSM-V, either as another category within the substance abuse, or another one more related to the impulse control disorders. Methods: A systematic review of the published literature about the subject was done using related MESH terms: "Internet", "Behavior, Addictive", "Impulse Control Disorders" e "Impulsive Behavior" between 2006 and march 2012. Results: The prevalence of Internet abuse and dependence has been difficult to determine because of the lack of consensus in the diagnostic criteria. As other psychiatric entities, genetic and psychological risk factors could be involved, as well as it could be associated with other comorbidities such as mood disorders, anxiety disorders, ADHD, alcohol abuse and eating disorders. Neuroimaging studies have shown evidence of neurobiological similarities with the structures involved in substance dependence. Conclusion: For answering many of these queries specific terminology is required, in order to validate new instruments for diagnosis and follow up as well, in order to in the future describe the risk factors, natural history and treatment alternatives for this emerging disease.

Introducción: Junto con la aparición de internet, ha ido cobrando interés problemas de salud emergentes asociados al uso de las nuevas tecnologías. La discusión no sólo se ha dado en los medios de comunicación, sino también a nivel académico. Inicialmente asociado al reporte de casos de "adicción a internet", para luego llegar al punto de incluso considerar su incorporación al futuro DSM-V, ya sea homologando el fenómeno a la adicción a substancias, o como un fenómeno emparentado con los trastornos por control de impulsos. Método: Se realizó una revisión sistemática de la literatura publicada sobre el tema utilizando los términos MESH afines: "Internet", "Behavior, Addictive", "Impulse Control Disorders" e "Impulsive Behavior" que se hubieran indexado desde el 2006 a marzo de 2012. Resultados: La prevalencia del abuso y dependencia a internet ha sido difícil de esclarecer por falta de consenso en los criterios diagnósticos. Tal como en otras entidades psiquiátricas podrían existir predisponentes genéticos y psicológicos así como asociación con comorbilidades tales como trastornos del ánimo, trastornos ansiosos, síndrome de déficit atencional e hiperactividad, abuso de alcohol y trastornos alimentarios. Pareciera haber correlato neurobiológico, demostrado en neuroimágenes, con las conocidas adicciones químicas. En cuanto al tratamiento, al no haber instrumentos para medir la respuesta, aún no existe evidencia de eficacia terapéutica. Conclusión: Para esclarecer muchas de estas dudas aún no resueltas hace falta terminología específica e instrumentos validados para diagnosticar y seguir a estos pacientes, para de esta manera describir sus factores de riesgo, curso natural y alternativas de tratamiento.

Unoccupied electronic structure of TiOCl studied using x-ray absorption near-edge spectroscopy.

We study the unoccupied electronic structure of the spin-1/2 quantum magnet TiOCl using x-ray absorption near-edge spectroscopy (XANES) at the Ti L and O K edges. We acquire data both in total electron and fluorescence yield modes (TEY and FY, respectively). While only the latter allows us to access the unconventional low-temperature spin-Peierls (SP) phase of TiOCl, the signal is found to suffer from significant self-absorption in this case. Nevertheless, we conclude from FY data that effects of the SP distortion on the electronic structure are absent in the incommensurate intermediate phase within experimental accuracy. The similarity of room-temperature FY and TEY data, the latter not being obscured by self-absorption, allows us to use TEY spectra for comparison with simulations. These are performed by means of cluster calculations in D(4h) and D(2h) symmetries using two different codes. We extract values of the crystal-field splitting and parameterize our results using the commonly seen notation of Slater, Racah and Butler. In all cases, good agreement with published values from other studies is found.

Photoemission of a doped Mott insulator: spectral weight transfer and a qualitative Mott-Hubbard description.

The spectral weight evolution of the low-dimensional Mott insulator TiOCl upon alkali-metal dosing has been studied by photoelectron spectroscopy. We observe a spectral weight transfer between the lower Hubbard band and an additional peak upon electron doping, in line with quantitative expectations in the atomic limit for changing the number of singly and doubly occupied sites. This observation is an unconditional hallmark of correlated bands and has not been reported before. In contrast, the absence of a metallic quasiparticle peak can be traced back to a simple one-particle effect.

Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures with hard x-ray photoelectron spectroscopy.

The conducting interface of LaAlO3/SrTiO3 heterostructures has been studied by hard x-ray photoelectron spectroscopy. From the Ti 2p signal and its angle dependence we derive that the thickness of the electron gas is much smaller than the probing depth of 4 nm and that the carrier densities vary with increasing number of LaAlO3 overlayers. Our results point to an electronic reconstruction in the LaAlO3 overlayer as the driving mechanism for the conducting interface and corroborate the recent interpretation of the superconducting ground state as being of the Berezinskii-Kosterlitz-Thouless type.

Nitrous oxide dimer: an ab initio coupled-cluster study of isomers, interconversions, and infrared fundamental bands, and experimental observation of a new fundamental for the polar isomer.

Improved quantum chemistry (coupled-cluster) results are presented for spectroscopic parameters and the potential energy surface for the N(2)O dimer. The calculations produce three isomer structures, of which the two lowest energy forms are those observed experimentally: a nonpolar C(2h)-symmetry planar slipped-antiparallel geometry (with inward-located O atoms) and a higher-energy polar C(s)-symmetry planar slipped-parallel geometry. Harmonic vibrational frequencies and infrared intensities for these isomers are calculated. The low-frequency intermolecular vibrational mode predictions should be useful for future spectroscopic searches, and there is good agreement in the one case where an experimental value is available. The frequency shifts for the high-frequency intramolecular stretching vibrations, relative to the monomer, were calculated and used to help locate a new infrared band of the polar isomer, which corresponds to the weaker out-of-phase combination of the nu(1) antisymmetric stretch of the individual monomers. The new band was observed in the region of the monomer nu(1) fundamental for both ((14)N(2)O)(2) and ((15)N(2)O)(2) using a tunable infrared diode laser to probe a pulsed supersonic jet expansion, and results are presented.

Prognostic and predictive implications of HER2 status for breast cancer patients.

Women diagnosed with breast cancer face many emotional and psychological challenges, which are often related to how they perceive their chances of survival. A number of factors are known to be indicators of breast cancer prognosis, including tumour type, size and grade, and lymph node status. These factors can be used alone or in combination to make management decisions based on a broad assessment of tumour aggression. However, identifying an independent marker of prognosis has proved more difficult. The human epidermal growth factor receptor-2 (HER2) is amplified/overexpressed in 25-30% of breast tumours. This event has been shown to be associated with poor prognosis in breast cancer patients. Initial observations indicated that median survival duration is reduced by at least 50% in patients who overexpress HER2 compared with those who do not overexpress the receptor. This finding has been supported by many subsequent studies and data are accumulating to indicate that the relationship holds for both node-negative and node-positive patients. This could be particularly important for identifying the 30% of node-negative patients who will progress despite therapy. HER2 status may also be able to predict the outcome of therapy. It appears likely that HER2 overexpression predicts for resistance to tamoxifen and other hormonal therapies. It is also possible that HER2-overexpressing patients may respond better to dose-intense anthracycline therapy and worse to cyclophosphamide/methotrexate/5-fluorouracil than non-overexpressing patients. Explaining these associations to patients may empower them to deal with the psychological effects of a diagnosis of breast cancer while providing hope for the future.

[Pharmacokinetic aspects of a combination of metoclopramide and paracetamol. Results of a human kinetic study and consequences for migraine patients]. / Pharmakokinetische Aspekte zur Kombination von Metoclopramid und Paracetamol. Ergebnisse einer Studie zur Humankinetik sowie Konsequenzen für den Migräne-Patienten.

An open trial was carried out in eight healthy male and female volunteers to examine the bioavailability as well as the main kinetic parameters of Migränerton (metoclopramide and paracetamol; CAS 364-64-5 and CAS 103-90-2, resp). in comparison with reliable literature data. The results reported here clearly show that the absorption of both active ingredients from the fixed combination is complete and that therapeutically relevant plasma concentrations are achieved within 30 min. Bioavailability as well as tmax, t1/2, and time-lag are comparable with data resulting from reliable and internationally acknowledged kinetic studies. The fixed combination was shown to be kinetically compatible with regard to all parameters determined for metoclopramide and paracetamol.

The importance of pharmacokinetic data on sulpiride: results of a bioequivalence study of two sulpiride 200 mg preparations following oral administration.

In a within-subject comparative trial in 16 healthy volunteers, the bioequivalence of two sulpiride 200 mg preparations was tested using a model-free method of calculation as well as assuming 2- and 3-compartment models. As to AUC act., AUC inf. and Cmax, the test preparation was shown to be significantly superior. Some other differences were found depending on which calculation method was used. The Cmax of the test preparation showed therapeutically relevant plasma concentrations of greater than 400 ng/ml, compared with about 300 ng/ml for the reference preparation. Based upon the raw data obtained, it was the aim of this study to gain further knowledge about other kinetic parameters on which only few data is available. T1/2 beta, clearance, volume of distribution and MRT were calculated using 2- and 3-compartment models. Comparisons with literature data were made and it resulted that a better description of the sulpiride kinetics was obtained when a 3-compartment model was used. Finally, the course of the plasma level was calculated by computer extrapolation assuming a thrice daily administration of sulpiride 200 mg. As a result, steady-state is reached after 3-4 days showing plasma concentrations around 650 ng (reference preparation) and 850 ng (test preparation).

[Pharmacokinetics and bioequivalence of two ibuprofen formulations]. / Pharmakokinetik und Bioäquivalenz von zwei Ibuprofen-Formulierungen.

In an open controlled randomized cross-over study in 16 healthy male and female volunteers the bioavailability of ibuprofen (CAS 15687-27-1) sugar-coated tablets (Dolo-Dolgit) was tested versus film-coated tablets containing ibuprofen 600 mg. As it results from the AUC evaluation, the bioavailability of both preparations is very good and almost identical. The ibuprofen concentrations achieved after administration of the test preparation, however, are significantly higher (Cmax = 52.03 micrograms/ml) than those achieved after the reference preparation showing a Cmax of 40.32 micrograms/ml. The tmax of 1.0 h is also significantly shorter than after the reference preparation (tmax = 1.5 h). The t1/2 beta after both the test and the reference preparation is within the known range, i.e. 1.8 h and 1.4 h, respectively. Even in long-term treatment with high dosages, administered 3-4 times daily, there is no accumulation of the active ingredient. Concerning the therapeutic relevance, special attention is to be given to the different time-dependent drug concentrations in the central compartment and in the target compartment. Both the higher Cmax and the shorter tmax achieved following administration of the test preparation are of therapeutic relevance.

[Concentrations of ibuprofen and the protein and pH value of synovial fluid and plasma following oral administration of ibuprofen in patients with arthritis]. / Konzentrationen von Ibuprofen und Eiweiss-Gehalt sowie pH-Wert in Kniegelenkserguss und Plasma nach oraler Gabe von Ibuprofen bei Arthritis-Patienten.

Concentrations of Ibuprofen and Protein Concentration and pH-Value in Synovial Fluid and Plasma Following Oral Administration of Ibuprofen in Patients Suffering from Arthritis. In 16 patients suffering from arthritis of the knee the concentration of ibuprofen in the synovial fluid was examined in correlation with the synovial fluid volume, cell count, pH value and protein concentration. The mean ibuprofen concentration in plasma 4 h after oral administration of 400 mg ibuprofen amounted to 15.45 micrograms/ml, the concentration in the synovial fluid was 9.4 micrograms/ml. Due to the inflammatory nature of the effusions the protein concentration in the synovial fluid was evidently increased to an average of 4.46 g/dl and thus was about 65% of the mean plasma protein concentration of 6.88 g/dl. The ibuprofen in the synovial fluid showed a correlation to the protein concentration. On the other hand, there were no significant differences between the pH value in the plasma and in the synovial fluid. There was no tendency to an acid pH. Furthermore, there was no correlation between ibuprofen concentration and cell count. The tests showed that the "accumulation" of the nonsteroidal antiinflammatory drug in the synovial fluid is positively correlated with the high protein concentration but not with the pH value.

Erythema chronicum migrans as the presenting manifestation of juvenile chronic myelocytic leukemia.

We describe the case of a 3-year-old boy who presented with typical clinical features of Lyme disease, including erythema chronicum migrans and arthritis. Over subsequent months, however, the clinical picture evolved into juvenile chronic myelocytic leukemia. To our knowledge, the combination of Lyme disease and juvenile chronic myelocytic leukemia has not been described. Dermatologic and other relevant clinical findings are presented, and the cause and effect relationship between these two rare entities is discussed.

Percutaneous ibuprofen therapy with Trauma-Dolgit gel: bioequivalence studies.

The plasma and tissue kinetics of ibuprofen after topical application of 5% Trauma-Dolgit gel were determined in two bioequivalence studies. In eight patients, high ibuprofen concentrations, largely within the therapeutic range, were found in subcutaneous tissue, tendon, muscles and joint capsule. In plasma, however, very low concentrations (decimal exponents below the therapeutically relevant plasma ibuprofen level even after repeated application) were found in nine volunteers. Based upon the comparison of oral and topical ibuprofen forms, the test preparation was found to be bioequivalent and, from a kinetic viewpoint, safe and effective.

[The percutaneous kinetics of ibuprofen from a cream formulation]. / Zur perkutanen Kinetik von Ibuprofen aus einer Cremezubereitung.

The percutaneous penetration of an ibuprofen cream at 5% (Dolgit Creme) was tested in guinea pigs. Already 20 min after application of the cream on the shaved skin high ibuprofen concentrations of about 10 micrograms/g were found in the subcutaneous and in the muscular tissue. The plasma concentrations reached only one tenth of the values ascertained in the tissues. 2 h after application the concentrations in the tissue increased by 50%, whereas the increase of the plasma concentrations was more significant. The results confirm in agreement with kinetic studies in man that ibuprofen penetrates from the tested formulation directly and very quickly in deeper tissues. The deviation of the active ingredient over the systemic circulation is improbable.

[Bioavailability of metoclopramide in a sustained-release preparation]. / Zur Bioverfügbarkeit von Metoclopramid aus einer retardierten Darreichungsform.

The aim of this study was to examine the pharmacokinetical behaviour of metoclopramide of Gastronetron retard capsules after a single administration to 8 healthy male volunteers. Determinations of the concentration of metoclopramide in the serum were made up to 24 h p.a. The calculation of the serum concentration curves was based on an open 2-compartment model. It has been proved that already 30 min after oral administration effective serum concentrations could be reached, which are maintained over about 24 h. An approximate value of 71% was obtained for the bioavailability of metoclopramide of Gastronerton retard capsules. The action achieved by the administration of 1 capsule Gastronerton retard per day can be considered equal to that of 3 single administrations of the conventional oral pharmaceutical form.

[Pharmacologic-toxicologic study of an ibuprofen-containing creme]. / Pharmakologisch-toxikologische Untersuchung einer Ibuprofen-haltigen Creme.

The antiphlogistic action, the percutaneous penetrability as well as the systemic and local tolerance of cremes with a different ibuprofen content after epicutaneous administration were examined in the rat, the guinea-pig and the rabbit. The antiphlogistic action was dose-dependently assessed on the carrageenin-induced edema of the rat paw and on UV-erythema in the guinea pig. The cotton-pellet test carried out on the rat evidenced only modest efficacy. The percutaneous penetration of ibuprofen after single epicutaneous application was obtained through the assessment of the active principle in the tissues and in the serum. The tests carried out for ascertaining the systemic and cutaneous tolerance did not evidence even after 3 to 4 weeks treatment with the ibuprofen creme any signs of intolerance due to the substance. In the investigation of the mucosal tolerance, the instillation of ibuprofen creme into the conjunctival sac of the rabbit led to strong yet reversible intolerance reactions in the conjunctiva and in the eyelid. Bearing on the results obtained on the whole, ibuprofen creme at 5% can be envisaged for clinical examination for the treatment of circumscribed rheumatic and traumatic diseases.

[Bioavailability of metoclopramide with special reference to relevant literature data]. / Zur Bioverfügbarkeit von Metoclopramid unter besonderer Berücksichtigung einschlägiger Literaturdaten.

An intraindividual comparative study of the pharmacokinetic properties of metoclopramide, the active principle of Gastronerton, and metoclopramide of a reference drug after one single administration was carried out on 6 male healthy volunteers. Gastronerton was available as ampoules, tablets, solution and capsules; the reference drug as ampoules, tablets and solution (all of them as commercial products). The concentrations of metoclopramide in the serum were determined until 24 h after administration. As one of the persons dropped out another volunteer was included. There were 6 cases for the intraindividual comparison of the parenteral/enteral form except for the comparison of the tablets/ampoules of the reference drug. An open 2-compartment model was taken as a basis for the calculation of the serum concentration curves and the pharmacokinetic parameters. With regard to the maximum serum concentrations, the preparations differed only insignificantly. The bioavailability results were as follows: metoclopramide of Gastronerton tablets 80.3%, metoclopramide of the tablets of the reference drug 57.6%, Gastronerton solution 76.7%, solution of the reference drug 49.7%. The bioavailability of metoclopramide of Gastronerton capsules was 54.8%. The half-life values were between 2.8 and 8.3 h with a mean value of 5 h.

[Comparative pharmacokinetics of paracetamol in humans following single oral and rectal administration (author's transl)]. / Vergleichende Humanpharmakokinetik von Paracetamol nach oraler und rektaler Einmalapplikation.

The pharmacokinetic behaviour of N-acetyl-p-aminophenol (paracetamol) after single dose applications of 500 mg and 1000 mg dosages in the form of liquids, tablets and suppositories was compared. The estimation of the pharmacokinetic constants by a simultaneous curve fitting with a direct search procedure, based on an open two-compartment model, showed for the liquid as well as for the tablet formulation a good conformable and dosage proportional behaviour of the relative bioavailability. In opposite to the oral application, the suppositories had a significantly reduced invasion kinetics with a comparable elimination kinetics characterized by a lowering of Cmax and an increase of Tmax-values with comparable AUCs. The calculation of collapse-coefficients showed, with the exception of one suppository formulation, for all administrations a pharmacokinetic behaviour deviating from an open one-compartment model. The clinical consequences resulting from the pharmacokinetic behaviour of the different galenic formulations and routes of administrations are discussed.