CLINICAL AND SURGICAL DILEMMAS IN OCTOGENARIAN PATIENTS WITH SMALL BOWEL OBSTRUCTION.

BACKGROUND: Small bowel obstruction (SBO) is a major problem in emergencies. Comorbidities increase morbimortality, which is reflected in higher costs. There is a lack of Latin American evidence comparing the differences in postoperative results and costs associated with SBO management. AIMS: To compare the risk of surgical morbimortality and costs of SBO surgery treatment in patients older and younger than 80 years. METHODS: Retrospective analysis of patients diagnosed with SBO at the University of Chile Clinic Hospital from January 2014 to December 2017. Patients with any medical treatment were excluded. Parametric statistics were used (a 5% error was considered statistically significant, with a 95% confidence interval). RESULTS: A total of 218 patients were included, of which 18.8% aged 80 years and older. There were no differences in comorbidities between octogenarians and non-octogenarians. The most frequent etiologies were adhesions, hernias, and tumors. In octogenarian patients, there were significantly more complications (46.3 vs. 24.3%, p=0.007, p<0.050). There were no statistically significant differences in terms of surgical complications: 9.6% in <80 years and 14.6% in octogenarians (p=0.390, p>0.050). In medical complications, a statistically significant difference was evidenced with 22.5% in <80 years vs 39.0% in octogenarians (p=0.040, p<0.050). There were 20 reoperated patients: 30% octogenarians and 70% non-octogenarians without statistically significant differences (p=0.220, p>0.050). Regarding hospital stay, the average was significantly higher in octogenarians (17.4 vs. 11.0 days; p=0.005, p<0.050), and so were the costs, being USD 9,555 vs. USD 4,214 (p=0.013, p<0.050). CONCLUSIONS: Patients aged 80 years and older with surgical SBO treatment have a higher risk of medical complications, length of hospital stay, and associated costs compared to those younger.

Conocimientos, prácticas y actitudes del manejo programático de la tuberculosis en estudiantes de medicina de Colombia / Knowledge, practices and attitudes of the programmatic management of tuberculosis among Colombian medical students

Introducción: La tuberculosis es una enfermedad infecciosa con alta carga de la enfermedad en Colombia, por lo que se espera que la educación médica sea estándar en todas las regiones y los estudiantes de medicina tengan competencias en el manejo operativo de la tuberculosis. Este estudio evaluó los conocimientos, actitudes y prácticas en tuberculosis en estudiantes de medicina de Colombia y los factores relacionados. Métodos: Cuestionario de evaluación de conocimientos, actitudes y prácticas en tuberculosis en estudiantes de medicina en Colombia, que cursaban semestre clínico y se encontraban inscritos en la reunión anual 2020 de la Asociación de Sociedades Científicas de Estudiantes de Medicina de Colombia (ASCEMCOL) para establecer el nivel de conocimientos en tuberculosis. Resultados: Se evidenció que los estudiantes de regiones con mayor carga de la enfermedad como el Eje Cafetero presenta puntajes más altos de forma diferencial a las otras regiones. Por otra parte, se observó que la experiencia propia del estudiante en el tamizaje para tuberculosis (prueba cutánea de la tuberculina PPD - Mantoux) y la experiencia en la atención de pacientes con tuberculosis en el entorno clínico están relacionadas a los conocimientos del manejo programático de la tuberculosis. Conclusión: El estudio demuestra bajo nivel de conocimientos, actitudes y prácticas del manejo programático de la tuberculosis en los estudiantes de medicina que cursaban semestres clínicos en Colombia. (AU)

Background: The tuberculosis is an infectious disease with high disease burden in Colombia, so medical education is expected to be standard in all regions and medical students have competencies in the operative management of tuberculosis. This study evaluated the knowledge, attitudes, and practices in tuberculosis in medical students in Colombia and related factors. Methods: Questionnaire for the evaluation of knowledge, attitudes, and practices in tuberculosis in medical students in Colombia, who were in clinical semesters and were registered at the 2020 annual meeting of the Asociación de Sociedades Científicas de Estudiantes de Medicina de Colombia (ASCEMCOL) to establish the level of knowledge in tuberculosis. Result: The study found that students from regions with a higher burden of disease, such as the Eje Cafetero had higher scores that those from other regions. On the other hand, it was observed that the student´s own experience in tuberculosis screening (tuberculin skin test PPD – Mantoux) and the clinical experience in care patients with tuberculosis are related to the knowledge of the programmatic management of tuberculosis. Conclusions: The study shows a low level of knowledge, attitudes, and practices of programmatic management of tuberculosis in medical students in clinical semester in Colombia. (AU)

Self-Consistent Study of GaAs/AlGaAs Quantum Wells with Modulated Doping.

In this work, the characterization and analysis of the physics of a GaAs quantum well with AlGaAs barriers were carried out, according to an interior doped layer. An analysis of the probability density, the energy spectrum, and the electronic density was performed using the self-consistent method to solve the Schrödinger, Poisson, and charge-neutrality equations. Based on the characterizations, the system response to geometric changes in the well width and to non-geometric changes, such as the position and with of the doped layer as well as the donor density, were reviewed. All second-order differential equations were solved using the finite difference method. Finally, with the obtained wave functions and energies, the optical absorption coefficient and the electromagnetically induced transparency between the first three confined states were calculated. The results showed the possibility of tuning the optical absorption coefficient and the electromagnetically induced transparency via changes to the system geometry and the doped-layer characteristics.

Exosomes-Based Nanomedicine for Neurodegenerative Diseases: Current Insights and Future Challenges.

Neurodegenerative diseases constitute a group of pathologies whose etiology remains unknown in many cases, and there are no treatments that stop the progression of such diseases. Moreover, the existence of the blood-brain barrier is an impediment to the penetration of exogenous molecules, including those found in many drugs. Exosomes are extracellular vesicles secreted by a wide variety of cells, and their primary functions include intercellular communication, immune responses, human reproduction, and synaptic plasticity. Due to their natural origin and molecular similarities with most cell types, exosomes have emerged as promising therapeutic tools for numerous diseases. Specifically, neurodegenerative diseases have shown to be a potential target for this nanomedicine strategy due to the difficult access to the brain and the strategy's pathophysiological complexity. In this regard, this review explores the most important biological-origin drug delivery systems, innovative isolation methods of exosomes, their physicochemical characterization, drug loading, cutting-edge functionalization strategies to target them within the brain, the latest research studies in neurodegenerative diseases, and the future challenges of exosomes as nanomedicine-based therapeutic tools.

Testosterone Therapy and Prostate Cancer: Incorporating Low-Level Evidence into Practical Recommendations.

The widely accepted absolute contraindication for administration of testosterone in hypogonadal men with prostate cancer has been questioned. Although recommendations from some professional associations still adhere to the traditional concepts, there is increasing relaxation of such positions. Currently, the evidence for definitive guidelines is unavailable and the clinician has to rely on incomplete but best attainable information. Under certain circumstances (successfully treated prostate cancer or active surveillance for low risk disease), testosterone administration is warranted. For those with intermediate or high-risk cancer, extreme caution seems advisable. The benefits must heavily outweigh the hazards. Ideally, these men should participate in clinical trials and registries. Competent initial assessment of individual circumstances and follow-up are mandatory.

Does price-cap regulation work for increasing access to contraceptives? Aggregate- and pharmacy-level evidence from Colombia.

Price caps through international reference pricing are widely used worldwide but not so commonly in over-the-counter markets. We study the short-term effects of a price cap regulation for oral contraceptives in Colombia, a market dominated by the presence of several branded generics with multiple active ingredients. Most of the regulated products were fourth-generation contraceptives, and the Colombian health benefits plan only covers second-generation ones, resulting in a de facto over-the-counter market. Our aim is to establish whether the regulation triggered a competitive response within and across product categories, by price levels and regulatory status. The panel data analysis of quarterly level data for 52 drugs (and 79 drugs in an expanded sample without transactions for some quarters) reveals a massive expansion of transactions, for the directly regulated products that were formerly the most expensive, and for the indirectly regulated (i.e., a regulated ingredient) among those with an intermediate price. Although this price reduction could have led to a crowd out of the publicly provided contraceptives, we show that this is not the case. Since the information system cannot trace the final consumers' purchases, we complement our analysis with an audit study involving 213 pharmacies in Bogota. We find that the price reduction was effectively transmitted to the final consumers.

Aproximación a la distribución de los costos directos de la diabetes tipo 2 en Colombia.

No disponible.

Clinical Efficacy of SARS-CoV-2 Vaccination in Hemodialysis Patients.

Introduction: The COVID-19 pandemic is a global public health problem. Patients with end-stage renal disease on hemodialysis are at a higher risk of infection and mortality than the general population. Worldwide, a vaccination campaign has been developed that has been shown to reduce severe infections and deaths in the general population. However, there are currently limited data on the clinical efficacy of vaccinations in the hemodialysis population. Methods: A national multicenter observational cohort was performed in Chile to evaluate the clinical efficacy of anti-SARS-CoV-2 vaccination in end-stage renal disease patients on chronic hemodialysis from February 2021 to August 2021. In addition, the BNT162b2 (Pfizer-BioNTech) and CoronaVac (Sinovac) vaccines were evaluated. The efficacy of vaccination in preventing SARS-CoV-2 infection, hospitalizations, and deaths associated with COVID-19 was determined. Results: A total of 12,301 patients were evaluated; 10,615 (86.3%) received a complete vaccination (2 doses), 490 (4.0%) received incomplete vaccination, and 1196 (9.7%) were not vaccinated. During follow-up, 1362 (11.0%) patients developed COVID-19, and 150 died (case fatality rate: 11.0%). The efficacy of the complete vaccination in preventing infection was 18.1% (95% confidence interval [CI]:11.8-23.8%), and prevention of death was 66.0% (95% CI:60.6-70.7%). When comparing both vaccines, BNT162b2 and CoronaVac were effective in reducing infection and deaths associated with COVID-19. Nevertheless, the BNT162b2 vaccine had higher efficacy in preventing infection (42.6% vs. 15.0%) and deaths (90.4% vs. 64.8%) compared to CoronaVac. Conclusion: The results of our study suggest that vaccination against SARS-CoV-2 in patients on chronic hemodialysis was effective in preventing infection and death associated with COVID-19.

Electronic Transport Properties in GaAs/AlGaAs and InSe/InP Finite Superlattices under the Effect of a Non-Resonant Intense Laser Field and Considering Geometric Modifications.

In this work, a finite periodic superlattice is studied, analyzing the probability of electronic transmission for two types of semiconductor heterostructures, GaAs/AlGaAs and InSe/InP. The changes in the maxima of the quasistationary states for both materials are discussed, making variations in the number of periods of the superlattice and its shape by means of geometric parameters. The effect of a non-resonant intense laser field has been included in the system to analyze the changes in the electronic transport properties by means of the Landauer formalism. It is found that the highest tunneling current is given for the GaAs-based compared to the InSe-based system and that the intense laser field improves the current-voltage characteristics generating higher current peaks, maintaining a negative differential resistance (NDR) effect, both with and without laser field for both materials and this fact allows to tune the magnitude of the current peak with the external field and therefore extend the range of operation for multiple applications. Finally, the power of the system is discussed for different bias voltages as a function of the chemical potential.

Study of Electronic and Transport Properties in Double-Barrier Resonant Tunneling Systems.

Resonant tunneling devices are still under study today due to their multiple applications in optoelectronics or logic circuits. In this work, we review an out-of-equilibrium GaAs/AlGaAs double-barrier resonant tunneling diode system, including the effect of donor density and external potentials in a self-consistent way. The calculation method uses the finite-element approach and the Landauer formalism. Quasi-stationary states, transmission probability, current density, cut-off frequency, and conductance are discussed considering variations in the donor density and the width of the central well. For all arrangements, the appearance of negative differential resistance (NDR) is evident, which is a fundamental characteristic of practical applications in devices. Finally, a comparison of the simulation with an experimental double-barrier system based on InGaAs with AlAs barriers reported in the literature has been obtained, evidencing the position and magnitude of the resonance peak in the current correctly.

Challenges in familial chylomicronemia syndrome diagnosis and management across Latin American countries: An expert panel discussion.

Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by extremely high triglyceride levels due to impaired clearance of chylomicrons from plasma. This paper is the result of a panel discussion with Latin American specialists who raised the main issues on diagnosis and management of FCS in their countries. Overall FCS is diagnosed late on the course of the disease, is characterized by heterogeneity on the occurrence of pancreatitis, and remains a long time in care of different specialists until reaching a lipidologist. Pancreatitis and secondary diabetes are frequently seen, often due to late diagnosis and inadequate care. Molecular diagnosis is unusual; however, loss of function variants on the lipoprotein lipase gene are apparently the most frequent etiology. A founder effect of the glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1 gene has been described in the northeast of Brazil. Low awareness of the disease amongst health professionals contributes to inadequate care and an inadequate patient journey.

Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field.

Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe-CdTe core-shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system's azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe-CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry.

Extracorporeal membrane oxygenation for tuberculosis pneumonia with empyema.

Acute respiratory distress syndrome (ARDS) caused by Mycobacterium Tuberculosis (TB) is a rare entity. Extracorporeal membrane oxygenation (ECMO) therapy had been used as an effective therapy for this cases, but the evidence is scarce. We present a case that took place in the middle of SARS-CoV2 pandemic. A 33-year-old female presented with ARDS due to pulmonary TB infection (pneumonia with empyema and pneumothorax), which required invasive mechanical ventilation with poor response. Long term veno-arterio-venous (VAV) ECMO, overlapped with veno-venous ECMO, was used as a salvage therapy with a good response for a total of 26 days. This is an example of the effectiveness of this therapy in this scenario, never described before. The fact that this therapy was used in the middle of SARS-CoV2 pandemic, with limited resources available, was remarkable, but it was encouraged by previous successful experiences.

A BCG success story: From prevention of tuberculosis to optimal bladder cancer treatment.

BCG remains the most important vaccine for tuberculosis 100 years after its first use, and over the past 4 decades it has become the most widely accepted, effective drug used in the treatment of aggressive localized bladder cancer. This review chronicles the narrow path that led to approval and world-wide acceptance of BCG immunotherapy for bladder cancer while immunotherapy trials in other malignancies were abandoned. Six intravesical instillations of 5x10^8 CFU of BCG weekly after bladder tumor resection, first reported in 1976, is superior to resection alone and resection plus intravesical chemotherapy. Maintenance of effective immune stimulation is surprisingly difficult, but 3 weekly treatments 3, 6, and 12, 18, 24, 30 and 36 months after induction produces further significant reduction in tumor recurrence. This 3 week BCG maintenance schedule alone has reduced disease progression and mortality in multicenter randomized clinical trials. In the new age of immuno-oncology patients with many types of cancer now benefit from immunotherapy, but currently these modern agents are prohibitively expensive for most of the world. In contrast, the low cost and therefore low profitability of BCG has resulted in recurrent shortages that threaten both bladder cancer patients and children at risk for tuberculosis and other serious infections. Humanity has greatly benefited from early 20th century science that developed BCG and the benevolence of doctors Calmette and Guerin who put people over profit and widely shared cultures of the vaccine. The 21st century is bringing new immunotherapies and greatly expanding the types of malignancies that can be treated. Recombinant technology is expected to improve both the efficacy and production of BCG, hopefully expanding the availability of BCG and relieving the recurring supply shortage for both vaccination and cancer therapy.

Self-Consistent Schrödinger-Poisson Study of Electronic Properties of GaAs Quantum Well Wires with Various Cross-Sectional Shapes.

Quantum wires continue to be a subject of novel applications in the fields of electronics and optoelectronics. In this work, we revisit the problem of determining the electron states in semiconductor quantum wires in a self-consistent way. For that purpose, we numerically solve the 2D system of coupled Schrödinger and Poisson equations within the envelope function and effective mass approximations. The calculation method uses the finite-element approach. Circle, square, triangle and pentagon geometries are considered for the wire cross-sectional shape. The features of self-consistent band profiles and confined electron state spectra are discussed, in the latter case, as functions of the transverse wire size and temperature. Particular attention is paid to elucidate the origin of Friedel-like oscillations in the density of carriers at low temperatures.

Total Sacrectomy for the Treatment of Advanced Pelvic Chondrosarcoma.

Primary tumors of sacrum are rare. The most common malignant tumors are metastasis, and only 6% of all malignant tumors arise from the sacrum. Chondrosarcoma is the third most common primary bone malignancy following myeloma and osteosarcoma. Surgery is usually the most important therapeutic modality; the wide en bloc excision remains the treatment of choice. These technically demanding procedures require a multidisciplinary expert team (neurosurgery, surgical and orthopedic oncology, colorectal surgery, and plastic surgery) involvement. We present in this article a case of a 52-year-old man who presented less infrequent symptoms, and the diagnosis was made in a very advanced stage. The wide surgical excision of the mass was performed by two different anterior and posterior approaches in one stage. The free surgical margins were difficult to achieve because it presented a voluminous tumor with invasion of the rectum, bone, and sacral plexus, but the age, low histological grade, and extensive experience in extreme pelvic surgery of our multidisciplinary team allowed approaching the patient with debulking surgery en bloc, successfully. Total hospital stay was 20 days. The patient was discharged without any complications. At the 6-months' follow-up, the patient showed no local recurrence.