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Briozzo A.C.,Austral University | Natale M.F.,Austral University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2017

We study the supercooled one-phase Stefan problem for a semi-infinite material with temperature-dependent thermal conductivity at the fixed face x= 0. We obtain sufficient conditions for data in order to have existence of a solution of similarity type, local in time and finite-time blow-up occurs. This explicit solution is obtained through the unique solution of an integral equation with the time as a parameter. © 2017, Springer International Publishing.

Aquino J.B.,Austral University
Stem Cells and Development | Year: 2017

Some late embryonic and adult postmigratory neural crest-derived cells (NCDCs) from diverse tissues were shown to grow as multipotent neurospheres. Neural crest stem cells (NCSCs) contained in these spheres were found to give rise not only to neuroectodermal derivatives but also to some of the progeny of the other embryonic germ layers. In this review, evidences regarding the in vivo properties of NCDCs contributing to NCSCs are discussed. Even though in many cases the final proof for the phenotype identity of in vivo cells generating NCSCs is lacking, some evidences suggest that such postmigratory NCDCs would differ from neural crest cells. The streamline of this review follows a historical perspective that helps understanding the advancements in knowledge of this field of research and highlighting its importance, in an appropriate context. Finally, the potential for regenerative medicine purpose of NCDCs and more specifically of tissues that can be a source of peripheral glia progenitors in the adult is underlined. © Mary Ann Liebert, Inc..

Ferder M.,University of Buenos Aires | Inserra F.,Austral University | Manucha W.,National University of Cuyo | Ferder L.,Ponce School of Medicine & Health Sciences
American Journal of Physiology - Cell Physiology | Year: 2013

This review attempts to show that there may be a relationship between inflamma-tory processes induced by chronic overstimulation of the renin-angiotensin system (RAS) and the worldwide deficiency of vitamin D (VitD) and that both disorders are probably associated with environmental factors. Low VitD levels represent a risk factor for several apparently different diseases, such as infectious, autoimmune, neu-rodegenerative, and cardiovascular diseases, as well as diabetes, osteoporosis, and cancer. Moreover, VitD insufficiency seems to predispose to hypertension, metabolic syndrome, left ventricular hypertrophy, heart failure, and chronic vascular inflamma-tion. On the other hand, inappropriate stimulation of the RAS has also been associated with the pathogenesis of hypertension, heart attack, stroke, and hypertrophy of the left ventricle and vascular smooth muscle cells. Because VitD receptors (VDRs) and RAS receptors are almost distributed in the same tissues, a possible link between VitD and the RAS is even more plausible. Furthermore, from an evolutionary point of view, both systems were developed simultaneously, actively participating in the regulation of inflammatory and immunological mechanisms. Changes in RAS activity and activation of the VDR seem to be inversely related; thus any changes in one of these systems would have a completely opposite effect on the other, making it possible to speculate that the two systems could have a feedback relationship. In fact, the pandemic of VitD deficiency could be the other face of increased RAS activity, which probably causes lower activity or lower levels of VitD. Finally, from a therapeutic point of view, the combination of RAS blockade and VDR stimulation appears to be more effective than either RAS blockade or VDR stimulation individually. © 2013 the American Physiological Society.

De Cavanagh E.M.V.,Austral University | Inserra F.,University of Buenos Aires | Ferder L.,Ponce School of Medicine & Health Sciences
Cardiovascular Research | Year: 2011

Protein and lipid oxidationmainly by mitochondrial reactive oxygen species (mtROS)was proposed as a crucial determinant of health and lifespan. Angiotensin II (Ang II) enhances ROS production by activating NAD(P)H oxidase and uncoupling endothelial nitric oxide synthase (NOS). Ang II also stimulates mtROS production, which depresses mitochondrial energy metabolism. In rodents, reninangiotensin system blockade (RAS blockade) increases survival and prevents age-associated changes. RAS blockade reduces mtROS and enhances mitochondrial content and function. This suggests that Ang II contributes to the ageing process by prompting mitochondrial dysfunction. Since Ang II is a pleiotropic peptide, the age-protecting effects of RAS blockade are expected to involve a variety of other mechanisms. Caloric restriction (CR)an age-retarding intervention in humans and animalsand RAS blockade display a number of converging effects, i.e. they delay the manifestations of hypertension, diabetes, nephropathy, cardiovascular disease, and cancer; increase body temperature; reduce body weight, plasma glucose, insulin, and insulin-like growth factor-1; ameliorate insulin sensitivity; lower protein, lipid, and DNA oxidation, and mitochondrial H2O2 production; and increase uncoupling protein-2 and sirtuin expression. A number of these overlapping effects involve changes in mitochondrial function. In CR, peroxisome proliferator-activated receptors (PPARs) seem to contribute to age-retardation partly by regulating mitochondrial function. RAS inhibition up-regulates PPARs; therefore, it is feasible that PPAR modulation is pivotal for mitochondrial protection by RAS blockade during rodent ageing. Other potential mechanisms that may underlie RAS blockades mitochondrial benefits are TGF-β down-regulation and up-regulation of Klotho and sirtuins. In conclusion, the available data suggest that RAS blockade deserves further research efforts to establish its role as a potential tool to mitigate the growing problem of age-associated chronic disease. © 2010 The Author.

Darlow B.A.,University of Otago | Gilbert C.E.,London School of Hygiene and Tropical Medicine | Quiroga A.M.,Austral University | Quiroga A.M.,National Ministry of Health
Clinics in Perinatology | Year: 2013

Retinopathy of prematurity (ROP) programs require collaboration between neonatologists, ophthalmologists, nurses, and allied health personnel, together with parents. The concept of a ROP program will vary according to the setting. However, in every situation there should be 2 main aspects: primary prevention of ROP through better overall care, and secondary prevention through case detection (often called screening), treatment, and follow-up. ROP programs will have different content and emphasis according to whether the setting is in an economically advanced or developing country. © 2013 Elsevier Inc.

We obtain for the two-phase Lamé-Clapeyron-Stefan problem for a semiinfinite material an equivalence between the temperature and convective boundary conditions at the fixed face in the case that an inequality for the convective transfer coefficient is satisfied. Moreover, an inequality for the coefficient which characterizes the solid-liquid interface of the classical Neumann solution is also obtained. This inequality must be satisfied for data of any phase-change material, and as a consequence the result given in Tarzia, Quart. Appl. Math., 39 (1981), 491-497 is also recovered when a heat flux condition was imposed at the fixed face.

Surgical resection is the only curative option for patients with gastrointestinal carcinomas. Unfortunately, the majority of patients are diagnosed in advanced stages when surgery is not possible. Moreover, the incidence and mortality for certain type of tumors such as hepatocellular carcinoma or pancreatic cancer are steadily increasing worldwide. In spite of the advances in the development of molecular targeted therapies for cancer, the impact on patient survival has been rather limited. It is unlikely that individual agents would be ultimately successful as monotherapy. There is a growing area of research focused on the combination of classical chemotherapy (e.g. cyclophosphamide, gemcitabine, paclitaxel and doxorubicin) with radiotherapy and/or gene therapy strategies. Combined approaches seem to be required due to multiple resistance mechanisms that tumors utilize to limit the activity of chemotherapeutic agents (e.g. the occurrence of multidrug resistance or epigenetic alterations), evade immune responses (e.g. induction of regulatory T cells or myeloid-derived suppressor cells) and to generate resistance against anti-angiogenesis or to radiotherapy by, for example, the induction of hypoxia-inducible factor 1. In addition, new studies suggest that combination of low dose of conventional chemotherapy and gene therapy could allow the development of synergic mechanisms able to achieve significant therapeutic effects against diverse tumors. Although cancer gene therapy is not yet available in clinical practice, advances being recently made look promising, especially when it was applied in combination with standard chemo- or radiotherapy protocols.

Knowledge of human resources in the area of health care is vital to make appropriate healthcare decisions. The Argentine Integrated Healthcare Information System (SISA), recently developed by the National Ministry of Health, registers all the active medical professionals in Argentina, and provides official data about the medical workforce. However, these data seem to be incomplete for most specialties. In the case of cardiology, the comparison between the Argentine Society of Cardiology and SISA registries indicates that almost half the number of specialists is not included in the SISA database. If only the official data were considered, we would have an adequate cardiologist-inhabitant ratio (74 cardiologists per million population), but findings in the present study show that this ratio would be much higher, indicating an overpopulation of specialists (140 cardiologists per million population). If health policy decision-makers did not cautiously evaluate preliminary official information from SISA, or did not recognize its precariousness, the true workforce in the specialty would be seriously underestimated. Yet, the SISA registry is a very good initiative, and all the scientific societies should provide information from their databases to improve its validity and usefulness. © 2014, Sociedad Argentina de Cardiologia. All rights reserved.

BACKGROUND: Triatoma infestans is the main vector of Chagas'disease in Southern Cone countries. In triatomines, symptoms suggesting neurotoxicity were observed after treatment with Jaburetox (Jbtx), the entomotoxic peptide obtained from jackbean urease. Here, we study its effect in the central nervous system (CNS) of this species.METHODS: Immunohistochemistry, Western blots, immunoprecipitation, two-dimensional electrophoresis, tandem mass spectrometry and enzymatic assays were performed.RESULTS: Anti-Jbtx antibody labeled somata of the antennal lobe only in Jbtx-treated insects. Western blot assays of nervous tissue using the same antibody reacted with a 61kDa protein band only in peptide-injected insects. Combination of immunoprecipitation, two-dimensional electrophoresis and tandem mass spectrometry identified UDP-N-acetylglucosamine pyrophosphorylase (UDP-GlcNAcP) as a molecular target for Jbtx. The activity of UDP-GlcNAcP increased significantly in the CNS of Jbtx-treated insects. The effect of Jbtx on the activity of nitric oxide synthase (NOS) and NO production was investigated as NO is a recognized messenger molecule in the CNS of T. infestans. NOS activity and NO levels decreased significantly in CNS homogenates of Jbtx-treated insects.CONCLUSIONS: UDP-GlcNAcP is a molecular target of Jbtx. Jbtx impaired the activity of T. infestans nitrergic system, which may be related with early behavioral effects.GENERAL SIGNIFICANCE: We report that the CNS of Triatoma infestans is a target for the entomotoxic peptide and propose that a specific area of the brain is involved. Besides potentially providing tools for control strategies of Chagas' disease vectors our data may be relevant in various fields of research as insect physiology, neurobiology and protein function. Copyright © 2014 Elsevier B.V. All rights reserved.

Caloia M.,Austral University | Caloia H.,Austral University | Pereira E.,University of Buenos Aires
Clinical Orthopaedics and Related Research | Year: 2012

Background: Irreparable tears to the scapholunate (SL) interosseous ligament area are common causes of mechanical wrist pain and yet treatment of this condition remains challenging. The reduction association of the SL joint (RASL) technique alleviates pain while preserving wrist function by creating a fibrous pseudarthrosis stabilized by a cannulated screw placed through the SL joint. Although arthroscopic RASL (ARASL) is a minimally invasive alternative to the open procedure, its effectiveness in controlling pain and preserving wrist function has not been established. Questions/purposes: To determinate whether ARASL was obtained relieve pain and restore function to the wrist. Patients and Methods: We reviewed eight patients (nine wrists) who had ARASL for SL instability with a reducible SL ligament tear (chronic lesion) from 2005 to 2009. Seven of eight were males and mean age was 44.5 years (range, 38-56 years). We recorded pain using a scale, the Disabilities of the Arm, Shoulder and Hand (DASH) score, grip strength, and range of motion (ROM). Minimum followup was 12 months (mean, 34.6 months; range, 12-43 months). Results: The visual analog pain score was rated 5.4 (range, 0-10) preoperatively and 1.5 (1-3) after ARASL. Postoperative grip strength of the wrist was 78% of the contralateral, unaffected wrist. The average postoperative wrist ROM was to 107°, 20% less than the preoperative ROM. The SL angle decreased from 70.5° to 59.3°. In three cases, screws were removed owing to loosening or symptoms. Conclusions: Our preliminary observations suggest ARASL for treating irreparable SL ligament tear is feasible, controls pain, and improves wrist function while preserving ROM. Larger series with longer followup are required to confirm our observations. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. © 2011 The Association of Bone and Joint Surgeons®.

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