Publications by authors named "Oscar Contreras"

Article Synopsis
  • The study tested the SAPS 3 scoring system for predicting mortality in ICU patients with blood cancers and found it didn't perform well.
  • Out of 273 patients studied, 119 died, yet the SAPS 3 score's ability to distinguish between survivors and those who died was low, indicating it isn't accurate.
  • The study concludes that clinical judgment should be prioritized over this scoring system for estimating mortality risk in these patients.
View Article and Find Full Text PDF

In this study, we synthesized and characterized pH-responsive Chitosan-AgCl-doped ZnO hybrid hydrogels and evaluated their potential for loading aquaculture bioactive compounds, and assessed their antimicrobial properties against a threatening pathogen associated with disease across a broad spectrum of warm water fish and invertebrates. Hydrogel characterization consisted of assessing morphology via SEM, composition via EDS, hydrogels' network components interactions via FT-IR and pH response through swelling behavior determinations. The swelling characterization of the synthesized hydrogels demonstrated a pH-responsive behavior, showing that low pH values caused the hydrogel polymeric network to expand and capture more of the aqueous solution.

View Article and Find Full Text PDF

Introduction: The detection of anxiety symptoms among health workers who care for patients infected with COVID-19 is a current priority. Fast and valid instruments are required for this population group. The objective is to establish the construct validity and reliability of the Generalised Anxiety Disorder (GAD-7) scale in Colombian doctors during the COVID-19 lockdown.

View Article and Find Full Text PDF

The detection of anxiety symptoms among health workers who care for patients infected with COVID-19 is a current priority. Fast and valid instruments are required for this population group. The objective is to establish the construct validity and reliability of the Generalised Anxiety Disorder (GAD-7) scale in Colombian doctors during the COVID-19 lockdown.

View Article and Find Full Text PDF

Conventional radiography of hands has been the imaging technique used for the early diagnosis of rheumatoid arthritis, considering its easy access and ability to reveal structural damage. However, it does not provide information about inflammatory activity or prognosis of this disease. On the other hand, magnetic resonance imaging is becoming the technique of choice for the early diagnosis of this disease and for the assessment of treatment response.

View Article and Find Full Text PDF

Chronic nonbacterial osteomyelitis (CNO) is a primary autoinflammatory bone disease that presents more frequently in children and is characterized by inflammatory bone lesions in the absence of an infectious etiology. There is little information of this disease in Latin America. The objective of the study was to evaluate demographic, clinical, laboratory, imaging, histopathology characteristics, and treatment responses of pediatric CNO patients.

View Article and Find Full Text PDF

Herein, a series of N-doped carbon nanotube (CNx) samples were obtained by modifying the synthesis temperature. Consequently, the proportion of graphitic nitrogen (Ngraph) in the samples was systematically increased as a function of temperature. This allowed evaluation of the role of the CNx graphitic nitrogen in the oxygen reduction reaction (ORR).

View Article and Find Full Text PDF

The current photodynamic therapy (PDT) is majorly hindered by the shallow penetration depth and oxygen dependency, limiting its application to deep-seated solid hypoxic tumors. Thus, it is meaningful to develop efficient X-ray mediated PDT system capable of generating reactive oxygen species (ROS) under both the normoxic and hypoxic conditions. Herein, we report the synthesis and characterization of nanocomposite, YAG:Pr@ZnO@PpIX with an amalgamation of UV-emitting YPrAlO (YAG:Pr) nanoscintillator, and zinc oxide (ZnO) and protoporphyrin IX (PpIX) as photosensitizers.

View Article and Find Full Text PDF

This data article provide results of the studies conducted to develop a mesoporous silica coated GdCeAlO nanoparticles loaded with a photosensitizer dye rose Bengal (RB) system (GAG@mSiO@RB) capable of producing reactive oxygen species (ROS) upon exposure to blue light. The data reported here is related with Jain et al. (2018) [1].

View Article and Find Full Text PDF

Nanoparticle (NP) and photosensitizer (PS) conjugates capable of X-ray photodynamic therapy (X-PDT) are a research focus due to their potential applications in cancer treatment. Combined with X-PDT, appropriate imaging properties of the nanocomposite will make it suitable for theranostics of deep lying tumors. In this work, we describe the development of magnetic-luminescent GdCeAlO nanoparticles (GAG) coated with mesoporous silica (mSiO) and loaded with rose bengal (RB) to yield a nanocomposite GAG@mSiO@RB capable of X-PDT.

View Article and Find Full Text PDF

Use of pesticides is usually related to overproduction of crops in order to overcome worldwide demand of food and alimentary safety. Nevertheless, pesticides are environmental persistent molecules, such as the organochlorine pesticides, which are often found in undesired places. In this work, we show that a hybrid nanomaterial (laccase-MSU-F) readily oxidizes the pesticide dichlorophen, reducing its acute genotoxicity and apoptotic effects.

View Article and Find Full Text PDF

The use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry.

View Article and Find Full Text PDF

Purpose: Calcific tendinitis is a frequent disorder caused by hydroxyapatite crystal deposition; however, bone erosions from calcific tendinitis are unusual. The spinal manifestation of this disease is calcific tendinitis of the longus colli muscle; this disease has never been described in the posterior aspect of the spine. We report a case of calcium hydroxyapatite crystal deposition involving the posterior cervical spine eroding the bone cortex.

View Article and Find Full Text PDF

Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column.

View Article and Find Full Text PDF

Lysosomal cysteine protease cathepsin L (CTSL) is believed to play a role in tumor progression and is considered a marker for clinically invasive tumors. Studies from our laboratory using the classical mouse skin carcinogenesis model, with 7,12-dimethyl-benz[a]anthracene (DMBA) for initiation and 12-O-tetradecanoylphorbol-13-acetate (TPA) for promotion, showed that expression of CTSL is increased in papillomas and squamous cell carcinomas (SCC). We also carried out carcinogenesis studies using Ctsl-deficient nackt (nkt) mutant mice on three different inbred backgrounds.

View Article and Find Full Text PDF

Background: Percutaneous biopsies have a good sensitivity and specificity for the diagnosis of bone lesions.

Aim: To report the experience with 270 percutaneous bone lesions biopsies guided with fluoroscopy or computed tomography.

Material And Methods: Retrospective review of the medical records of 270 patients (mean age 53.

View Article and Find Full Text PDF

Background: Bone marrow edema syndrome (BMES) is a rare clinical condition. Its etiology is unknown and it can be seen in different locations. In the case of the hip, avascular necrosis is the main differential diagnosis.

View Article and Find Full Text PDF

Background: Paget disease of bone (PD) is a localized disorder of bone remodeling, which leads to bone fragility and deformity. In Chile PD is uncommon.

Aim: To study clinical and demographic characteristics of patients with PD seen in the Clinical Hospital of the Catholic University.

View Article and Find Full Text PDF