Chondrogenic Potential of Human Adipose-Derived Mesenchymal Stromal Cells in Steam Sterilized Gelatin/Chitosan/Polyvinyl Alcohol Hydrogels.

Cross-linked polymer blends from natural compounds, namely gelatin (Gel), chitosan (CS), and synthetic poly (vinyl alcohol) (PVA), have received increasing scrutiny because of their versatility, biocompatibility, and ease of use for tissue engineering. Previously, Gel/CS/PVA [1:1:1] hydrogel produced via the freeze-drying process presented enhanced mechanical properties. This study aimed to investigate the biocompatibility and chondrogenic potential of a steam-sterilized Gel/CS/PVA hydrogel using differentiation of human adipose-derived mesenchymal stromal cells (AD-hMSC) and cartilage marker expression. AD-hMSC displayed fibroblast-like morphology, 90% viability, and 69% proliferative potential. Mesenchymal profiles CD73 (98.3%), CD90 (98.6%), CD105 (97.0%), CD34 (1.11%), CD45 (0.27%), HLA-DR (0.24%); as well as multilineage potential, were confirmed. Chondrogenic differentiation of AD-hMSC in monolayer revealed the formation of cartilaginous nodules composed of glycosaminoglycans after 21 days. Compared to nonstimulated cells, hMSC-derived chondrocytes shifted the expression of CD49a from 2.82% to 40.6%, CD49e from 51.4% to 92.2%, CD54 from 9.66 to 37.2%, and CD151 from 45.1% to 75.8%. When cultured onto Gel/CS/PVA hydrogel during chondrogenic stimulation, AD-hMSC changed to polygonal morphology, and chondrogenic nodules increased by day 15, six days earlier than monolayer-differentiated cells. SEM analysis showed that hMSC-derived chondrocytes adhered to the surface with extended filopodia and abundant ECM formation. Chondrogenic nodules were positive for aggrecan and type II collagen, two of the most abundant components in cartilage. This study supports the biocompatibility of AD-hMSC onto steam-sterilized GE/CS/PVA hydrogels and its improved potential for chondrocyte differentiation. Hydrogel properties were not altered after steam sterilization, which is relevant for biosafety and biomedical purposes.

Commercially Accessible High-Performance Aluminum-Air Battery Cathodes through Electrodeposition of Mn and Ni Species on Fuel Cell Cathodes.

This study presents a cost-effective method for producing high-performance cathodes for aluminum-air batteries. Commercial fuel cell cathodes are modified through electrodeposition of nickel and manganese species. The optimal conditions for electrodeposition are determined using a combination of structural (Raman, SEM, TEM) and electrochemical (LSV, EI, discharge curves) characterization techniques. The structural analysis confirms successful incorporation of nickel and manganese species onto the cathode surface. Electrochemical tests demonstrate enhanced electrochemical activity compared to unmodified cathodes. By combining the favorable properties of electrodeposited manganese species with nickel species, a high-performance cathode is obtained. The developed cathode exhibits capacities of 50 mA h cm-2 in aluminum-air batteries across a wide range of current densities. The electrodeposition method proves effective in improving electrochemical performance. A key advantage of this method is its simplicity and cost-effectiveness. The use of commercially available materials and well-established electrodeposition techniques allows for easy scalability and commercialization. This makes it a viable option for large-scale production of high-performance cathodes for the next-generation energy storage devices.

Controversies in neuroimmunology: multiple sclerosis, vaccination, SARS-CoV-2 and other dilemas / Controversias en neuroinmunología: esclerosis múltiple, vacunación, SARS-CoV-2 y otros dilemas

Neuroimmunology is a discipline that increasingly broadens its horizons in the understanding of neurological diseases. At the same time, and in front of the pathophysiological links of neurological diseases and immunology, specific diagnostic and therapeutic approaches have been proposed. Despite the important advances in this discipline, there are multiple dilemmas that concern and filter into clinical practice. This article presents 15 controversies and a discussion about them, which are built with the most up-to-date evidence available. The topics included in this review are: steroid decline in relapses of multiple sclerosis; therapeutic recommendations in MS in light of the SARS-CoV-2 pandemic; evidence of vaccination in multiple sclerosis and other demyelinating diseases; overview current situation of isolated clinical and radiological syndrome; therapeutic failure in multiple sclerosis, as well as criteria for suspension of disease-modifying therapies; evidence of the management of mild relapses in multiple sclerosis; recommendations for prophylaxis against Strongyloides stercolaris; usefulness of a second course of immunoglobulin in the Guillain-Barré syndrome; criteria to differentiate an acute-onset inflammatory demyelinating chronic polyneuropathy versus Guillain-Barré syndrome; and, the utility of angiotensin-converting enzyme in neurosarcoidosis. In each of the controversies, the general problem is presented, and specific recommendations are offered that can be adopted in daily clinical practice.

La neuroinmunología es una disciplina que cada vez amplía más sus horizontes en la comprensión de las enfermedades neurológicas. Contemporáneamente, y a la luz de los nexos fisiopatológicos de las enfermedades neurológicas y la inmunología, se han planteado enfoques diagnósticos y terapéuticos específicos. A pesar de los importantes avances de esta disciplina, existen múltiples dilemas que le conciernen y se filtran en la práctica clínica. En esta revisión, se presentan y discuten 15 controversias, las cuales se construyen con la información clínica disponible más actualizada. Los temas incluidos son: disminución de esteroides en recaídas de esclerosis múltiple; recomendaciones terapéuticas en esclerosis múltiple a la luz de la pandemia por el SARS-CoV-2; evidencia de vacunación en esclerosis múltiple y en otras enfermedades desmielinizantes; panorama actual del síndrome clínico y radiológico aislado; y fallas terapéuticas en esclerosis múltiple; además, criterios para suspender las terapias modificadoras de la enfermedad; evidencia del manejo en recaídas leves; recomendaciones para la profilaxis contra Strongyloides stercolaris; utilidad de un segundo ciclo de inmunoglobulina en el síndrome de Guillain-Barré; criterios para diferenciar una polineuropatía crónica desmielinizante inflamatoria de inicio agudo de un síndrome de Guillain-Barré y, utilidad de la enzima convertidora de angiotensina en neurosarcoidosis. En cada una de las controversias, se presenta la problemática general y se ofrecen recomendaciones específicas que pueden adoptarse en la práctica clínica diaria.

Controversias en neuroinmunología: esclerosis múltiple, vacunación, SARS-CoV-2 y otros dilemas / Controversies in neuroimmunology: multiple sclerosis, vaccination, SARS-CoV-2 and other dilemas

La neuroinmunología es una disciplina que cada vez amplía más sus horizontes en la comprensión de las enfermedades neurológicas. Contemporáneamente, y a la luz de los nexos fisiopatológicos de las enfermedades neurológicas y la inmunología, se han planteado enfoques diagnósticos y terapéuticos específicos. A pesar de los importantes avances de esta disciplina, existen múltiples dilemas que le conciernen y se filtran en la práctica clínica. En esta revisión, se presentan y discuten 15 controversias, las cuales se construyen con la información clínica disponible más actualizada. Los temas incluidos son: disminución de esteroides en recaídas de esclerosis múltiple; recomendaciones terapéuticas en esclerosis múltiple a la luz de la pandemia por el SARS-CoV-2; evidencia de vacunación en esclerosis múltiple y en otras enfermedades desmielinizantes; panorama actual del síndrome clínico y radiológico aislado; y fallas terapéuticas en esclerosis múltiple; además, criterios para suspender las terapias modificadoras de la enfermedad; evidencia del manejo en recaídas leves; recomendaciones para la profilaxis contra Strongyloides stercolaris; utilidad de un segundo ciclo de inmunoglobulina en el síndrome de Guillain-Barré; criterios para diferenciar una polineuropatía crónica desmielinizante inflamatoria de inicio agudo de un síndrome de Guillain-Barré y, utilidad de la enzima convertidora de angiotensina en neurosarcoidosis. En cada una de las controversias, se presenta la problemática general y se ofrecen recomendaciones específicas que pueden adoptarse en la práctica clínica diaria.

Neuroimmunology is a discipline that increasingly broadens its horizons in the understanding of neurological diseases. At the same time, and in front of the pathophysiological links of neurological diseases and immunology, specific diagnostic and therapeutic approaches have been proposed. Despite the important advances in this discipline, there are multiple dilemmas that concern and filter into clinical practice. This article presents 15 controversies and a discussion about them, which are built with the most up-to-date evidence available. The topics included in this review are: steroid decline in relapses of multiple sclerosis; therapeutic recommendations in MS in light of the SARS-CoV-2 pandemic; evidence of vaccination in multiple sclerosis and other demyelinating diseases; overview current situation of isolated clinical and radiological syndrome; therapeutic failure in multiple sclerosis, as well as criteria for suspension of disease-modifying therapies; evidence of the management of mild relapses in multiple sclerosis; recommendations for prophylaxis against Strongyloides stercolaris; usefulness of a second course of immunoglobulin in the Guillain-Barré syndrome; criteria to differentiate an acute-onset inflammatory demyelinating chronic polyneuropathy versus Guillain-Barré syndrome; and, the utility of angiotensin-converting enzyme in neurosarcoidosis. In each of the controversies, the general problem is presented, and specific recommendations are offered that can be adopted in daily clinical practice.

Physical and geochemical characteristics of land mud volcanoes along Colombia's Caribbean coast and their societal impacts.

The Caribbean coast is characterized by the presence of mud volcanoes, a secondary phenomenon of volcanism similar to mud diapirs for its development and evolution, but different in terms of geological features and forms. These mud volcanoes are often located close to tectonic faults and oil and gas deposits. Their geological context is dominated by the presence of clay sediments and brackish water, that favors the decomposition of organic material and the formation of methane. Mud volcanoes can thus be an important reservoir of hydrocarbons. This paper aims to fill the existing gap in the knowledge of mud volcanoes (MVs) of Colombia. We analyze the physical and geochemical characteristics of nine onshore mud volcanoes located in the Departments of Atlántico (La Laguna), Bolívar (Las Palomas, La Bonga, Santa Catalina, Yerbabuena, Clemencia, and Membrillal), Cordóba (Los Olivos), and Magdalena (Cañaveral). These structures present a kaolinitic composition, except for La Laguna mud volcano in which smectite is predominant. Apart from tectonic processes, this influences the shape and size of MVs and, also, the type and frequency of eruptions. The abundance of methane in all sites confirms the thermogenic origin of these structures. MVs are often considered landscape attractions as well as a therapeutic resources, but unfortunately they also represent a serious risk for the local communities, due to the frequent unexpected, eruptions, sometimes accompanied by the release of toxic gases or by landslides, that can damage the infrastructures and hurt the population living in the area. The MVs are classified into five vulnerability classes using a novel synthetic index which could improve the understanding of risks associated with the presence of MVs in proximity to towns and infrastructures.

An Online Training Intervention on Prehospital Stroke Codes in Catalonia to Improve the Knowledge, Pre-Notification Compliance and Time Performance of Emergency Medical Services Professionals.

Strokes are a time-dependent medical emergency. The training of emergency medical service (EMS) professionals is essential to ensure the activation of stroke codes with pre-notification, as well as a rapid transfer to achieve early therapy. New assessment scales for the detection of patients with suspected large vessel occlusion ensures earlier access to endovascular therapy. The aim of this study was to evaluate the impact on an online training intervention focused on the Rapid Arterial oCclusion Evaluation (RACE) scoring of EMS professionals based on the prehospital stroke code in Catalonia from 2014 to 2018 in a pre-post intervention study. All Catalonian EMS professionals and the clinical records from primary stroke patients were included. The Kirkpatrick model guided the evaluation of the intervention. Data were collected on the knowledge on stroke recognition and management, pre-notification compliance, activated stroke codes and time performance of EMS professionals. Knowledge improved significatively in most items and across all categories, reaching a global achievement of 82%. Pre-notification compliance also improved significantly and remained high in the long-term. Increasingly higher notification of RACE scores were recorded from 60% at baseline to 96.3% in 2018, and increased on-site clinical care time and global time were also observed. Therefore, the online training intervention was effective for increasing EMS professionals' knowledge and pre-notification compliance upon stroke code activation, and the wide adoption of a new prehospital scale for the assessment of stroke severity (i.e., the RACE scale) was achieved.

Vitamin D and other environmental risk factors in Colombian patients with multiple sclerosis.

OBJECTIVE: The aim of this study was to explore the association between MS and vitamin D levels, as well as Epstein-Barr virus (EBV) seropositivity and smoking history in a Colombian population. METHODS: We conducted a cross-sectional study between 2017 and 2018. We measured vitamin D levels and EBV antibody titers and administered a questionnaire to assess dietary habits, smoking, second-hand smoking and duration of smoking, sunlight exposure, physical activity, and personal and family history in individuals with and without multiple sclerosis during adolescence. A multivariable logistic regression model was then performed to explore the association between vitamin D status and MS. RESULTS: A total of 87 individuals with MS (mean age 40.9 years; 65.52% females) and 87 without MS (mean age 55 years; 65.52% females) were included in the analysis. In the multivariable analysis, after controlling for supplementation vitamin D levels did not differ between both groups and no difference was found regarding tobacco smoke exposure. The proportion of individuals who tested positive for anti-EBV nuclear antigen was significantly higher in individuals with MS (95.4% vs 82.76%, p = 0.028) CONCLUSION: : We did not find a statistically significant association between MS and vitamin D levels while anti-EBV nuclear antigen titers behaved as previously described in the literature. This study provides new evidence of the association between MS and different risk factors in our country, reinforcing the hypothesis that the pathogenesis of MS is multifactorial. Further studies are needed to better define the association between environmental factors and the development of MS in low prevalence areas.

Apendicectomía por único puerto asistida por laparoscopia versus técnica abierta convencional localizada, en pacientes con apendicitis aguda en el Hospital Universitario Clínica San Rafael / Appendectomy by single port assisted by laparoscopy versus conventional open localized technique, in patients with acute appendicitis at the Hospital Universitario Clínica San Rafael

Introducción. La apendicectomía por puerto único, asistida por laparoscopia,ofrece una alternativa terapéutica en el abordaje de la apendicitis aguda. En el presente estudio, se evalúa el beneficio terapéutico de la técnica por único puerto asistida por laparoscopia y se compara esta técnica con la apendicectomía abierta.Materiales y métodos. Se trata de un estudio observacional analítico retrospectivo de cohorte, llevado a cabo en el Hospital Universitario Clínica San Rafael, de Bogotá. Se incluyeron 106 pacientes mayores de 15 años con apendicitis aguda, que fueron sometidos a apendicectomía por puerto único, asistida por laparoscopia o apendi-cectomía abierta. La relación entre el grupo con apendicectomía por laparoscopia y el de técnica abierta, fue de 1:1. Se incluyeron variables sociodemográficas, clínicas y quirúrgicas (tiempo quirúrgico, frecuencia de infección del sitio operatorio, estancia hospitalaria, dolor, reingresos y resultado estético).Resultados. La edad promedio fue de 32 años y la mayoría de los pacientes eran de sexo masculino. El tiempo operatorio fue menor en los casos de apendicectomía por puerto único, asistida por laparoscopia, con un prome-dio de 34,1 minutos. Según la escala análoga, el dolor posoperatorio fue de 2,2 con la técnica laparoscópica y de 3,2 con la apendicectomía abierta (p<0,05). Hubo ocho veces más reingresos entre los casos de apendicectomía abierta en comparación con la apendicectomía por un puerto, y el resultado estético fue satisfactorio en todos con esta última técnica. No se encontraron diferencias significativas en la estancia hospitalaria o la infección del sitio operatorio. La razón de momios (odds ratio, OR) fue inferior a 1 en variables como dolor, reingreso y menor tiempo quirúrgico, lo cual indica una menor probabilidad, en los que se usó un solo puerto. Discusión. La técnica por un solo puerto es segura, reproducible, equiparable en términos de días de estancia hospitalaria e infección de sitio operatorio, e incluso, produce mejores resultados en el tiempo quirúrgico, las escalas de dolor y el número de reingresos

Introduction: Laparoscopic assisted single port appendectomy offers an alternative approach to acute appen-dicitis. This study compares this technique versus open appendectomy and determine its therapeutic benefit. Materials and methods: retrospective cohort analytical observational study at the San Rafael Clinical University Hospital, Bogotá.Results: We included 106 patients older than 15 years with acute appendicitis who underwent appendectomy for single port assisted by laparoscopy versus appendectomy. The relationship between exposed and unexposed was 1:1. Sociodemographic, clinical and surgical variables were included (surgical time, frequency of infection of the operative site, hospital stay, pain, readmissions, and aesthetic result). Average age was 32 years, being the majority males. We observed less operative time in appendectomy for single port assisted by laparoscopy (34.1 min), postoperative pain measured according to analogous pain scale, was 2.2 in laparoscopy and 3.2 in open appendectomy (p: <0.05). Eight times more readmissions were observed in open appendectomy versus lap appendectomy, with satisfactory aesthetic results of 100% in single port. No significant differences were found in hospital stay and operative site infection. OR less than 1 was observed in variables such as pain, readmission and shorter surgical time indicating lower probability in single port. Discussion: The single port technique is a safe, reproducible technique, comparable in terms of days of hospital stay and operative site infection and even with better results in surgical time, pain scales and fewer readmissions

Impulsivity traits in patients with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a demyelinating disease with a lifetime prevalence of 4.41/100000 in Bogota, Colombia. It is known that it can be related with neuropsychiatric disorders, increasing by a factor of three the prevalence of depression in MS patients compared to general population. However, less attention has been given to the association between MS and impulsive behavior. METHODS: This cross-sectional study compared the levels of impulsivity controlling for the presence of MS. 60 patients with MS and 60 sex- and age-matched subjects without MS were included. In order to assess depression and impulsivity, participants completed the 13-item short form of the Beck Depression Inventory (BDI-SF), the self-report Barratt Impulsiveness Scale version 11 (BIS-11) and the Immediate and Delayed Memory Tasks (IMT-DMT) as an objective measure of impulsive behavior. RESULTS: Total scores, motor and cognitive subscales on the BIS-11 were significantly higher in the MS group. However, median BDI-SF score was also higher in MS patients than in subjects without MS (p < 0.001). To rule out depression as a confounding factor, stratification was performed using the BDI-SF score. In the subgroup of individuals with a BDI-SF< 8, the BIS-11 cognitive subscale scores were significantly higher in patients with MS than in subjects without MS (p = 0.041). In the IMT/DMT test, subjects with MS had a fewer number of correct detections than did subjects without MS, after controlling for BDI-SF score (p = 0.0001/p = 0.003). The ratio of commission errors to correct detections in the IMT was significantly higher in the MS group (p = 0.011). CONCLUSION: Patients with MS showed higher levels of cognitive impulsivity than subjects without MS. Objective measures for impulsiveness further support this finding. Impulsiveness scales scores might be biased by depression, which should be considered when assessing impulsivity in MS.

Determinantes biológicos de mortalidad neonatal, en una población de mujeres adolescentes y adultas de un hospital en Colombia / Biological determinants of neonatal mortality, in a population of adolescent and adult women of a hospital in Colombia

INTRODUCTION. La muerte neonatal está asociada a determinantes maternos, obstétricos, fetales, neonatales y los cuidados de la salud. OBJETIVO Establecer los determinantes asociados a mortalidad neonatal en una unidad de cuidados intensivos de Colombia. Métodos. Estudio de casos y controles anidado en una cohorte, donde se incluyeron 5567 neonatos vivos, de los cuales fallecieron 125. Con Stata 11.0® se construyeron las estadísticas descriptivas y mediante odds ratio (intervalo de confianza 95%) se establecieron las asociaciones. La regresión logística fue empleada en el análisis multivariado. Se consideró un valor de p<0,05 como significativo. RESULTADOS. La mortalidad se presentó en 2,25% de los neonatos, ocurriendo 76,80% de las muertes entre 0-7 días. Los determinantes maternos y obstétricos asociados de manera independiente a mortalidad neonatal incluyeron número de visitas en el control prenatal menor a 6, trabajo de parto prematuro espontáneo, sangrados del tercer trimestre e hipertensión arterial crónica. Entre los determinantes neonatales, la necesidad de reanimación cardiorrespiratoria, prematuridad o bajo peso al nacer, infecciones bacterianas graves, enfermedad de membrana hialina, hipertensión pulmonar, malformaciones congénitas y anomalías cromosómicas y cardiomiopatía hipertrófica, se asociaron independientemente a mortalidad neonatal. Para las complicaciones y eventos adversos hubo asociación independiente y estadísticamente significativa para infecciones asociadas a la atención en salud, hemorragia intraventricular grados III y IV de Papille y hemorragia pulmonar. CONCLUSIONES. La mortalidad neonatal obedeces a determinantes maternos, obstétricos y feto-neonatales, por lo cual el mejoramiento de los cuidados de estos, reduciría la mortalidad neonatal.

INTRODUCTION. Neonatal death is associated with maternal, obstetric, fetal, neonatal, and health determinants. Objective. To establish the determinants associated with neonatal mortality in a Colombian intensive care unit. METHODS. Case-control study nested in a cohort, where 5567 live infants were included, of which 125 died. Stata 11.0® descriptive statistics were constructed and associations were established using odds ratio (95% confidence interval). Logistic regression was used in the multivariate analysis. A value of p <0.05 was considered significant. RESULTS. Mortality occurred in 2.25% of neonates, with 76.80% of deaths occurring between 0-7 days. Maternal and obstetric determinants independently associated with neonatal mortality included numbers of visits in prenatal control less than 6, spontaneous preterm labor, third trimester bleeding, and chronic hypertension. Among neonatal determinants, the need for cardiorespiratory resuscitation, prematurity or low birth weight, severe bacterial infections, hyaline membrane disease, pulmonary hypertension, congenital malformations and chromosomal abnormalities, and hypertrophic cardiomyopathy were independently associated with neonatal mortality. For complications and adverse events, there was an independent and statistically significant association for infections associated with health care, intravenous haemorrhage degrees III and IV of Papille, and pulmonary hemorrhage. CONCLUSIONS. Neonatal mortality is due to maternal, obstetric and fetal-neonatal determinants, so improving neonatal care will reduce neonatal mortality.

Seronegative Paraneoplastic Limbic Encephalitis Associated with Thymoma.

Paraneoplastic limbic encephalitis is an autoimmune syndrome characterized by the acute or subacute onset of encephalopathy, memory loss, confusion, temporal lobe seizures, and behavioral and mood changes. Although most patients with paraneoplastic limbic encephalitis have antineuronal antibodies, advances in the field now permit the diagnosis without autoantibody test results. In this case illustrating the new diagnostic criteria, we report a 70-year-old woman who was brought to the emergency room after the acute onset of cognitive impairment, altered mental status, and choreoathetoid movements. Brain magnetic resonance imaging showed hyperintense signals in both temporal lobes, and a chest computed tomogram revealed a thymoma. Because the patient met current diagnostic criteria for autoimmune limbic encephalitis, we were able to start treatment before her antibody tests were processed. The patient received immunotherapy and her tumor was resected. Her choreoathetoid movements disappeared and her other neurologic symptoms improved. Her cerebrospinal fluid proved to be negative for paraneoplastic limbic encephalitis antibodies. Most but not all patients with paraneoplastic limbic encephalitis associated with thymoma have evidence of paraneoplastic antibodies. Prompt management of the underlying malignancy determines whether patients survive and may minimize future cognitive and functional impairment. Practicing neurologists and psychiatrists should be aware of this diagnosis.

HLA-DRB1*14 is a protective allele for multiple sclerosis in an admixed Colombian population.

OBJECTIVE: The aim of this study was to determine ancestry informative markers, mitochondrial DNA haplogroups, and the association between HLA-DRB1 alleles and multiple sclerosis (MS) in a group of patients from Bogotá, Colombia. METHODS: In this case-control study, genomic DNA was isolated and purified from blood samples. HLA-DRB1 allele genotyping was done using PCR. Mitochondrial hypervariable region 1 was amplified and haplogroups were determined using HaploGrep software. Genomic ancestry was estimated by genotyping a panel of ancestry informative markers. To test the association of HLA polymorphisms and MS, we ran separate multivariate logistic regression models. Bonferroni correction was used to account for multiple regression tests. RESULTS: A total of 100 patients with MS (mean age 40.4 ± 12 years; 70% females) and 200 healthy controls (mean age 37.6 ± 11 years; 83.5% females) were included in the analysis. Ancestry proportions and haplogroup frequencies did not differ between patients and controls. HLA-DRB1*15 was present in 31% of cases and 13.5% of controls, whereas HLA-DRB1*14 was present in 5% of cases and 15.5% of controls. In the multivariate model, HLA-DRB1*15 was significantly associated with MS (odds ratio [OR] = 3.05, p < 0.001), whereas HLA-DRB1*14 was confirmed as a protective factor in our population (OR = 0.16, p = 0.001). CONCLUSIONS: This study provides evidence indicating that HLA-DRB1*15 allele confers susceptibility to MS and HLA-DRB1*14 allele exerts resistance to MS in a highly admixed population. This latter finding could partially explain the low prevalence of MS in Bogotá, Colombia.

Tissue-type plasminogen activator triggers the synaptic vesicle cycle in cerebral cortical neurons.

The active zone (AZ) is a thickening of the presynaptic membrane where exocytosis takes place. Chemical synapses contain neurotransmitter-loaded synaptic vesicles (SVs) that at rest are tethered away from the synaptic release site, but after the presynaptic inflow of Ca(+2) elicited by an action potential translocate to the AZ to release their neurotransmitter load. We report that tissue-type plasminogen activator (tPA) is stored outside the AZ of cerebral cortical neurons, either intermixed with small clear-core vesicles or in direct contact with the presynaptic membrane. We found that cerebral ischemia-induced release of neuronal tPA, or treatment with recombinant tPA, recruits the cytoskeletal protein ßII-spectrin to the AZ and promotes the binding of SVs to ßII-spectrin, enlarging the population of SVs in proximity to the synaptic release site. This effect does not require the generation of plasmin and is followed by the recruitment of voltage gated calcium channels (VGCC) to the presynaptic terminal that leads to Ca(+2)-dependent synapsin I phosphorylation, freeing SVs to translocate to the AZ to deliver their neurotransmitter load. Our studies indicate that tPA activates the SV cycle and induces the structural and functional changes in the synapse that are required for successful neurotransmission.

Osseointegration improvement by plasma electrolytic oxidation of modified titanium alloys surfaces.

Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.

Comparación entre inseminación intrauterina e inseminación intraperitoneal con hiperestimulación ovarica usando semen lavado. Profamilia 1994-1995 / Comparison between intrauterine and intraperitoneal insemination with washed semen accompanied by ovarian hypersimulation. Profamilia, 1994 – 1995

Se realizó un estudio experimental de intervención de tipo prospectivo para comparar los resultados de la inseminación intrauterina (IIU) y la inseminación intraperitoneal directa (DIPI) precedidas de hiperestimulación ovárica con citrato de clomifeno y gonadotropina menopáusica humana. Se realizaron 31 ciclos de inseminación en 19 pacientes con diagnóstico de infertilidad por factor masculino, factor cervical, endometriosis I-II e infertilidad inexplicada. Se utilizó semen del esposo, lavado por medio de “jumping”. Las parejas fueron asignadas aleatoriamente a uno de los dos tipos de inseminación. Con IIU se observó un índice de embarazos por ciclos del 7 por ciento, y de embarazos por paciente del 9 por ciento. En el grupo de DIPI no se observaron embarazos. Sin embargo, estas diferencias no alcanzaron significancia estadística debido posiblemente al pequeño tamaño muestral. No se reportaron complicaciones con el esquema de hiperestimulación ovárica ni con el procedimiento de inseminación en sí. El esquema de hiperestimulación indujo una respuesta ovárica óptima, con un promedio de de 3 folículos por ciclo. Se encontró que ambos tipos de inseminación con seguros y bien tolerados por las pacientes, los mismo que el esquema de hiperestimulación utilizando. Se requieren más trabajos comparativos para establecer cual de los dos es más efectivo...