University of Puerto Rico, Medical Sciences Campus

About: University of Puerto Rico, Medical Sciences Campus is a education organization based out in San Juan, Puerto Rico, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 1711 authors who have published 1496 publications receiving 27756 citations.

Real-time detection of telomerase activity in cancer cells using a label-free electrochemical impedimetric biosensing microchip

Abstract: The enzyme telomerase is present in about 85% of human cancers which makes it not only a good target for cancer treatment but also an excellent marker for cancer detection. Using a single stranded DNA probe specific for telomerase binding and reverse transcription tethered to an interdigital gold electrode array surface, the chromosome protection provided by the telomerase was replicated and followed by electrochemical impedance spectroscopy as an unlabeled biosensor. Using this system designed in-house, easy and affordable, impedance measurements were taken while incubating at 37 °C and promoting the probe elongation. This resulted in up to 14-fold increase in the charge transfer resistance when testing a telomerase-positive nuclear extract from Jurkat cells compared to the heat-inactivated telomerase-negative nuclear extract. The electron transfer process at the Au electrodes was studied before the elongation, at different times after the elongation, and after desorption of non-specific binding.

Psychometric properties of the Barkley Deficits in Executive Functioning Scale: A Spanish-Language Version in a community sample of puerto rican adults.

Abstract: Performance-based measures have shown some limitation in the assessment of executive functioning (EF) and rating scales have been proposed as an alternative. Our aim was to conduct a comprehensive psychometric evaluation of the Barkley Deficits in Executive Functioning Scale (BDEFS), as administered in 452 Latino community adults (65.5% female). The BDEFS was back-translated into Spanish. We performed exploratory factor analysis (EFA) to assess the structure of the translated BDEFS and to compare it with the original five-factor structure based on the English-language version. Confirmatory factor analysis (CFA) was performed to test the original language structure of the instrument, and also a modified version with items that loaded equally in both versions. The Adult Self-Report Scale was used to screen for ADHD symptoms. We assessed invariance on the latent factor's mean by age and gender, and to estimate associations with ADHD symptom dimensions. The five-factor structure of the BDEFS was partially supported by EFA/CFA, in which 78 out of 89 items loaded similar to the original English-language structure. Factor scores were significantly associated with ADHD symptom dimensions. Model-based contrasts revealed that inattention was primarily associated with disorganization, time-management and motivational aspects of EF; hyperactivity was predominantly related to self-restraint and self-regulation factors. The BDEFS seemingly assesses similar dimensions of the EF construct in English and in the present Spanish-language versions. Factor scores were differentially associated with ADHD subtypes. Replication and confirmation of the Spanish-language BDEFS in a larger sample is advised. (PsycINFO Database Record

In the Context of Polymorphism: Accurate Measurement, and Validation of Solubility Data

Abstract: Solubility measurements for polymorphic compounds are often accompanied by solvent-mediated phase transformations. In this study, solubility measurements from undersaturated solutions are employed to investigate the solubility of the two most stable polymorphs of flufenamic acid (FFA forms I and III), tolfenamic acid (TA forms I and II), and the only known form of niflumic acid (NA). The solubility was measured from 278.15 to 333.15 K in four alcohols of a homologous series (methanol, ethanol, 1-propanol, n-butanol) using the polythermal method. It was established that the solubility of these compounds increases with increasing temperature. The solubility curves of FFA forms I and III intersect at ~315.15 K (42 °C) in all four solvents, which represents the transition temperature of the enantiotropic pair. In the case of TA, the solubility of form II could not be reliably obtained in any of the solvents because of the fast solvent-mediated phase transformation. The solubility of the only known form of NA was also determined, and no other polymorphs of NA were observed. The experimental solubility data of FFA (forms I and III), TA (form I), and NA in these four solvents was correlated using the modified Apelblat and λh model equations. The correlated and experimentally determined solubility data obtained serves to (i) guide the accurate determination of the solubility for polymorphic compounds, (ii) assess the role of the solvent in mediating transformations, and (iii) provide a route to engineer advanced crystallization processes for these pharmaceutical compounds.

Glycolytic Enzyme Activity Is Essential for Domestic Cat (Felis catus) and Cheetah (Acinonyx jubatus) Sperm Motility and Viability in a Sugar-Free Medium

Abstract: We have previously reported a lack of glucose uptake in domestic cat and cheetah spermatozoa, despite observing that these cells produce lactate at rates that correlate positively with sperm function. To elucidate the role of glycolysis in felid sperm energy production, we conducted a comparative study in the domestic cat and cheetah, with the hypothesis that sperm motility and viability are maintained in both species in the absence of glycolytic metabolism and are fueled by endogenous substrates. Washed ejaculates were incubated in chemically defined medium in the presence/absence of glucose and pyruvate. A second set of ejaculates was exposed to a chemical inhibitor of either lactate dehydrogenase (sodium oxamate) or glyceraldehyde-3-phosphate dehydrogenase (alpha-chlorohydrin). Sperm function (motility and acrosomal integrity) and lactate production were assessed, and a subset of spermatozoa was assayed for intracellular glycogen. In both the cat and cheetah, sperm function was maintained without exogenous substrates and following lactate dehydrogenase inhibition. Lactate production occurred in the absence of exogenous hexoses, but only if pyruvate was present. Intracellular glycogen was not detected in spermatozoa from either species. Unexpectedly, glycolytic inhibition by alpha-chlorohydrin resulted in an immediate decline in sperm motility, particularly in the domestic cat. Collectively, our findings reveal an essential role of the glycolytic pathway in felid spermatozoa that is unrelated to hexose metabolism or lactate formation. Instead, glycolytic enzyme activity could be required for the metabolism of endogenous lipid-derived glycerol, with fatty acid oxidation providing the primary energy source in felid spermatozoa.