Central University of the Caribbean

Bayamon, Puerto Rico

The Universidad Central del Caribe is a private non-profit university in Bayamon, Puerto Rico offering graduate studies and professional certifications in health science. It was founded in 1976 in the municipality of Cayey, but since 1990 all its facilities have been integrated into one campus at the grounds of the Dr. Ramón Ruiz Arnau University Hospital in Bayamón. Wikipedia.

Time filter
Source Type

Bykhovskaia M.,Central University of the Caribbean | Bykhovskaia M.,Wayne State University
Biophysical Journal | Year: 2015

Synaptotagmin 1 (Syt1) is a synaptic vesicle protein that serves as a calcium sensor of neuronal secretion. It is established that calcium binding to Syt1 triggers vesicle fusion and release of neuronal transmitters, however, the dynamics of this process is not fully understood. To investigate how Ca2+ binding affects Syt1 conformational dynamics, we performed prolonged molecular dynamics (MD) simulations of Ca2+-unbound and Ca2+-bound forms of Syt1. MD simulations were performed at a microsecond scale and combined with Monte Carlo sampling. We found that in the absence of Ca2+ Syt1 structure in the solution is represented by an ensemble of conformational states with tightly coupled domains. To investigate the effect of Ca2+ binding, we used two different strategies to generate a molecular model of a Ca2+-bound form of Syt1. First, we employed subsequent replacements of monovalent cations transiently captured within Syt1 Ca2+-binding pockets by Ca2+ ions. Second, we performed MD simulations of Syt1 at elevated Ca2+ levels. All the simulations produced Syt1 structures bound to four Ca2+ ions, two ions chelated at the binding pocket of each domain. MD simulations of the Ca2+-bound form of Syt1 revealed that Syt1 conformational flexibility drastically increased upon Ca2+ binding. In the presence of Ca2+, the separation between domains increased, and interdomain rotations became more frequent. These findings suggest that Ca2+ binding to Syt1 may induce major changes in the Syt1 conformational state, which in turn may initiate the fusion process. © 2015 Biophysical Society.

Skatchkov S.N.,Central University of the Caribbean | Woodbury-Farina M.A.,University of Puerto Rico at San Juan | Eaton M.,Central University of the Caribbean
Psychiatric Clinics of North America | Year: 2014

This review focuses on the roles of glia and polyamines (PAs) in brain function and dysfunction, highlighting how PAs are one of the principal differences between glia and neurons. The novel role of PAs, such as putrescine, spermidine, and spermine and their precursors and derivatives, is discussed. However, PAs have not yet been a focus of much glial research. They affect many neuronal and glial receptors, channels, and transporters. They are therefore key elements in the development of many diseases and syndromes, thus forming the rationale for PA-focused and glia-focused therapy for these conditions. © 2014 Elsevier Inc.

Marino-Nieto J.,Central University of the Caribbean
Boletín de la Asociación Médica de Puerto Rico | Year: 2011

Osteochondromas are the most common benign tumors of the skeleton. They usually arises from the metaphysial region of long bones. Only 10% of rib tumors are benign, and osteochondromas, account for half of these. These tumors typically begin to grow before puberty and continue until bone maturation is reached. We discuss a case of a 7-year-old boy found on physical examination to have a painless bony swelling arising as an outgrowth from the left fourth rib. Patient was taken to the operation room for a radical excision. CT scan and histopathological examination confirmed that the lesion was a non malignant osteochondroma. Costal osteochondroma is a rare but important condition to recognize due to its complications, such as reduced range of movement, pain, cosmetic abnormalities and bursitis. Costal osteochondromas tend to grow into the chest cavity and such lesions are rarely exophytic. There have been no previous reports of exophytic costal osteochondroma of this size in a child.

Schikorski T.,Central University of the Caribbean
Communicative and Integrative Biology | Year: 2014

The synaptic vesicle (SV) cycle was initially discovered at the neuromuscular junction using electron microscopy (EM) analysis.1 With the introduction of fluorescent probes that are able to monitor real-time cellular events in live cells, EM analysis was pushed to the side lines because it could not provide meaningful kinetic analyses of the various steps in the synaptic vesicle cycle. © 2014 Landes Bioscience.

Bykhovskaia M.,Central University of the Caribbean
Seminars in Cell and Developmental Biology | Year: 2011

Synaptic vesicles are organized in clusters, and synapsin maintains vesicle organization and abundance in nerve terminals. At the functional level, vesicles can be subdivided into three pools: the releasable pool, the recycling pool, and the reserve pool, and synapsin mediates transitions between these pools. Synapsin directs vesicles into the reserve pool, and synapsin II isoform has a primary role in this function. In addition, synapsin actively delivers vesicles to active zones. Finally, synapsin I isoform mediates coupling release events to action potentials at the latest stages of exocytosis. Thus, synapsin is involved in multiple stages of the vesicle cycle, including vesicle clustering, maintaining the reserve pool, vesicle delivery to active zones, and synchronizing release events. These processes are regulated via a dynamic synapsin phosphorylation/dephosphorylation cycle which involves multiple phosphorylation sites and several pathways. Different synapsin isoforms have unique and non-redundant roles in the multifaceted synapsin function. © 2011 Elsevier Ltd.

Schikorski T.,Central University of the Caribbean
Methods in Molecular Biology | Year: 2010

Cells communicate via endo- and exocytosis with their environment and neighboring cells. At synapses of the nervous system, fast exocytosis is coupled to fast endocytosis, which forms the basis for neurotransmitter release. The introduction of the unique fluorescent FM dyes allowed the monitoring of fast synaptic vesicle exo-endocytic cycling during live imaging sessions and after photoconversion of FM dyes into an electron-dense diaminobenzidine polymer synaptic vesicle cycling can be studied in the electron microscope. This protocol describes FM dye labeling of synaptic vesicles of cultured hippocampal neurons and photoconversion of the fluorescent synaptic vesicles for analysis in the electron microscope (EM). © Springer Science+Business Media, LLC 2010.

Schikorski T.,Central University of the Caribbean
Methods in Molecular Biology | Year: 2010

The detection of proteins with antibodies that are conjugated to gold particles has been a major asset to cell biology and the neurosciences, and knowledge about the subcellular location of antigens has formed the basis for many hypotheses regarding protein function. Many protocols have been developed since the introduction of colloidal gold to immunocytochemistry. The two most widely used techniques, however, are based on transmission electron microscopy and consist of either immunolabeling before the specimens are embedded in resin (pre-embedding immunogold labeling) or immunolabeling after embedding in resin (post-embedding immunogold labeling). The following protocol describes a pre-embedding procedure that gives reliable results with all antibodies that produce adequate staining as observed with a light microscope. This procedure results in almost perfect preservation of the ultrastructure. The procedure employs thick sectioning using a vibratome, permeabilization of membranes with Triton X-100, and immunolabeling with fluorescently conjugated Nanogold antibodies, followed by gold enhancement and embedding for electron microscopy. We also discuss some limitations inherent to pre-embedding immunogold labeling. © Springer Science+Business Media, LLC 2010.

Mikhail I.,Central University of the Caribbean
Boletín de la Asociación Médica de Puerto Rico | Year: 2010

1,1 '-Diethyl-2,2'-cyanine iodide (decynium22; D22) is a potent blocker of the organic cation family of transporters (EMT/OCT) known to move endogenous monoamines like dopamine and norepinephrine across cell membranes. Decynium22 is a cation with a relatively high affinity for all members of the OCT family in both human and rat cells. The mechanism through which decynium22 blocks OCT transporters are poorly understood. We tested the hypothesis that denynium22 may compete with monoamines utilizing OCT to permeate the cells. Using the ability of D22 to aggregate and produce fluorescence at 570 nm, we measured D22 uptake in cultured astrocytes. The rate of D22 uptake was strongly depressed by acid pH and by elevated external K+. The rate of uptake was similar to that displayed by 4-(4-(dimethylamino)-styryl)-N-methylpyridinium (ASP+), a well established substrate for OCT and high-affinity Na+-dependent monoamine transporters. These data were supported by measurement of electrogenic uptake using whole cell voltage clamp recording. Decynium22 depressed norepinephrine, but not glutamate uptake. These data are also consistent with the described OCT transporter characteristics. Taken together, our results suggest that decynium22 accumulation might be a useful instrument to study monoamine transport in the brain, and particularly in astrocytes, where they may play a prominent role in monoamine uptake during brain dysfunction related to monoamines (like Parkinson disease) and drug addiction.

Agency: NSF | Branch: Standard Grant | Program: | Phase: ORGANIZATION | Award Amount: 704.86K | Year: 2012

Numerous neurological disorders result from disruptions in the communication between nerve cells. Neurons communicate by releasing neuronal transmitters from nerve endings. Impaired transmitter release may produce certain forms of epilepsy. Transmitter molecules are packed into synaptic vesicles, and the preparation of vesicles for release is regulated by numerous proteins. Synapsin is the most abundant synaptic vesicle protein, and its deficiency causes epileptic seizures. Past work shows elimination of another vesicle protein, Rab3a, rescues epilepsy caused by synapsin deletion. This project will investigate how these two proteins interact within nerve endings. To do this, genetically engineered mice that lack synapsin, Rab3a, or both proteins, will be studied. High resolution microscopy to observe vesicle dynamics, and electrical recording will be performed to monitor neuronal activity. In addition, a computational model of the nerve ending will be developed to test whether hypotheses of the protein interaction correctly predict how synapsin and Rab3a affect the release of transmitters. The results of our study will elucidate the mechanisms of synapsin-dependent epilepsy and will suggest new strategies for its treatment.

The Universidad Central del Caribe (UCC) is a Hispanic serving institution which strives to provide Puerto Rican students with first-rate education and scientific training. The present project creates a foundation for an excellent training program. The experiments will be performed by graduate, undergraduate, and medical students, and thus the project will provide a support for the students careers. The project involves collaboration between the UCC and the Wayne State University, and this creates advantageous opportunities for Puerto Rico students to have a practice in a research intense institution. Thus, this project will integrate research and training, advance careers of Puerto Rico students, and help to promote workforce diversity.

Schikorski T.,Central University of the Caribbean
Methods in Molecular Biology | Year: 2010

A modern electron microscopic approach to the investigation of the structural organization of proteins and subcellular structures demands the use of molecular genetic techniques. The successful implementation of genetic techniques is closely tied to a reporter gene such as the green fluorescent protein (GFP). Although GFP has been widely used for light microscopy, it has many limitations for use in electron microscopy. In the search for a reporter gene for electron microscopy, interest in the use of horseradish peroxidase (HRP) DNA has recently increased, and several studies already have proven the feasibility of HRP expression in mammalian cells. Here, we describe a protocol that uses a HRP chimera to label the endoplasmic reticulum of HEK cells. © Springer Science+Business Media, LLC 2010.

Loading Central University of the Caribbean collaborators
Loading Central University of the Caribbean collaborators